Library

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • 1985-1989  (1,764)
  • 1987  (1,764)
  • Cell & Developmental Biology  (1,362)
  • Atomic, Molecular and Optical Physics  (275)
  • pharmacokinetics  (127)
Material
Years
  • 1985-1989  (1,764)
Year
  • 101
    ISSN: 1573-0646
    Keywords: ICRF-187 ; phase I ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract ICRF-187 was given to 62 evaluable patients with advanced solid tumors in a Phase I clinical trial. Weekly infusions were given in dosages ranging from 0,85 g/m2 to 7.42 g/m2 for a total of four weeks with a two week rest period between courses. Dose-limiting hematological toxicity was seen in heavily pretreated patients at a dose of 3.8 g/m2/week. All patients also developed reversible SGOT elevations. In patients with less prior therapy hematologic toxicity was not dose-limiting but hepatotoxicity, manifest by transient SGOT levels greater than 5 times baseline was seen at 7.42 g/m2/week even though only 3/6 patients could receive 4 consecutive weekly doses. At virtually all dose levels tested some patients developed anemia. Other toxicities, including alopecia, nausea, vomiting and reversible serum amylase elevations, were mild. Cumulative monthly doses achieved on this weekly schedule are significantly higher than a 48-hour infusion or daily times 3 or 5 schedule in adults and a daily times 3 schedule in children. Pharmacokinetic studies in eight patients indicate that the drug disappears from the plasma biphasically with a terminal t1/2 of 3.2 +0.9 hr. The total clearance was 288.7 + 85.0 ml/hr/kg and the volume of distribution (Vda) was 1.3 ± 0.4 1/kg. Pharmacokinetics were not dose-dependent from 3.8–7.4 g/m2 and no difference in pharmacokinetics was found in patients studied during the first and second treatments of a course. If Phase II trials of ICRF-187 are to be pursued on this schedule, appropriate doses would be 3.8 g/m2/week × 4 for heavily pretreated and 7.42 g/m2/week for “good risk” patients. Because of erratic hematologic toxicity in heavily pretreated patients, some might only tolerate three weekly doses. In good risk patients transaminitis was significant but reversible, thus, Phase II protocols should include dose escalation schemata.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 102
    Electronic Resource
    Electronic Resource
    Springer
    Investigational new drugs 5 (1987), S. 365-371 
    ISSN: 1573-0646
    Keywords: caracemide ; phase I ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary A Phase I study of caracemide evaluating a short intravenous infusion repeated every 21 days is presented. Patients were entered at 85 mg/m2 with subsequent escalation levels of 170, 425, 595, and 795 mg/m2. Mild to moderate nausea and vomiting occurred at all dose levels. An apparent allergic reaction was observed at the 425 mg/m2 level. A “burning pain” originating in the mucosal areas of the head and neck, progressing to the chest and abdomen, was noted at the 425 mg/m2 level. Because of this observation, the infusion time was extended to 4 h. At the 795 mg/m2, this toxicity precluded completion of the 4 h infusion. Pharmacokinetic evaluation disclosed blood levels of 0.74–2.31 μg/ml at the 425 mg/m2 during the 0.5 h infusion. At the same dose for a 4 h infusion time, blood levels were 0.15–0.18 μg/ml. At 595 mg/m2 administered as a 4 h infusion, blood levels increased to 0.33 ± 0.14 μg/ml. The drug was cleared rapidly from the blood compartment with a half-life of 2.5 min and a total body clearance of 11.5 1/min/m2. No partial or complete response was observed. However, an advanced colon carcinoma patient experienced subjective pain relief with a decrease in carcinoembryonic antigen. The dose-limiting toxicity of caracemide using the 4 h infusion was an intolerable “burning pain” with a maximum tolerated dose of 795 mg/m2. Further characterization of this dose-limiting toxicity is required prior to further clinical evaluation of caracemide.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 103
    ISSN: 1573-8221
    Keywords: prazosin ; prazosin metabolite ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 104
    Electronic Resource
    Electronic Resource
    Springer
    Bulletin of experimental biology and medicine 103 (1987), S. 658-660 
    ISSN: 1573-8221
    Keywords: ethanol ; rats ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 105
    Electronic Resource
    Electronic Resource
    Springer
    Bulletin of experimental biology and medicine 104 (1987), S. 941-944 
    ISSN: 1573-8221
    Keywords: ethanol ; predisposition ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 106
    Electronic Resource
    Electronic Resource
    Springer
    Journal of pharmacokinetics and pharmacodynamics 15 (1987), S. 145-177 
    ISSN: 1573-8744
    Keywords: Chemotherapy ; mutation ; resistance ; compartmental analysis ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The pharmacokinetics of antineoplastic drugs based on compartmental models are combined with deterministic exponential growth models of tumors containing drug-resistant and sensitive cells. Model predictions for single-drug therapy are compared with in vivodata obtained by other investigators for L1210 t-cell leukemia in mice treated with BCNU and AraC and for in vitrotreatment of L1210 with Ara-C. The model and data compare favorably in terms of rate of tumor growth and duration of drug action for both constant infusion and bolus delivery of the drugs.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 107
    ISSN: 1573-8744
    Keywords: Structure-activity relationships ; pharmacokinetics ; protein binding ; glycopeptide antibiotics ; charge ; lipophilicity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract In previous studies of the pharmacokinetics and urinary excretion of nine glycopeptides with diverse isoelectric points (pI),as pIdecreases, the total systemic and renal clearance, urinary recovery, and volume of distribution decrease, whereas the half-life increases. With glycopeptides of similar pI,clearance decreases and half-life increases with increasing lipophilicity. The present study examines the serum protein binding of these glycopeptide antibiotics in mouse, rat, and human serum and calculates the previously reported pharmacokinetic parameters for these drugs based on unbound concentration. Increased negative charge and lipophilicity increase serum protein binding (90-fold, fu 83% to 0.96%), which decreases the renal clearance and total systemic clearance (90-fold, 16.4 to 0.18 ml/min/kg) of these drugs. Increased serum protein binding also decreases the volume of distribution of these compounds, but this change is relatively small (sixfold, 755 to 131 ml/kg) compared with the change in total systemic clearance causing an increase in elimination half-life (25-fold, 20 to 492 min). The results demonstrate that the large differences in the total systemic clearance and half-life of these glycopeptide antibiotics are primarily due to dramatic differences in serum protein binding and notto differences in the intrinsic elimination processes (enzymes or transport proteins). It appears that the same physical-chemical properties that govern the protein binding and pharmacokinetics of small organic molecules govern the disposition of these high-molecular weight glycopeptide antibiotics.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 108
    Electronic Resource
    Electronic Resource
    Springer
    Journal of pharmacokinetics and pharmacodynamics 15 (1987), S. 255-269 
    ISSN: 1573-8744
    Keywords: pharmacokinetics ; singie-point dose prediction ; dosage ; minimax estimation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The single-point dose prediction method is based on the observation that for drugs obeying single compartment elimination kinetics there is a nearly constant reciprocal relation between the plasma level at a fixed time following a single loading dose and the dose that is required to maintain the desired steady state plasma level of the drug. This paper describes an improved method for choosing a plasma sampling time and a proportionality constant. It applies to either drugs administered intravenously or to drugs whose rates of absorption from the site of administration are very rapid compared to their rates of elimination from the body. The sampling time and proportionality constant chosen are those that minimize the maximum relative deviation of the maintenance dose estimated by the single-point method from the dose that would be estimated if the individual's true elimination rate constant were known. The paper also supplies a method to determine the maximum error that may be introduced into the estimation of the maintenance dose by using the single-point method.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 109
    ISSN: 1573-8744
    Keywords: cotinine ; nicotine ; rat ; tissue distribution ; pharmacokinetics ; constant-rate infusion ; physiological model ; iv bolus ; osmotic minipump
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The tissue partition of cotinine was measured by a GC-MS method following a 6-day constant-rate input of nicotine and cotinine to male rats by means of an osmotic minipump. The tissue-to-blood partition coefficients of cotinine were calculated for adipose (0.08), brain (0.48), heart muscle (0.55), intestinal (0.53), hepatic (0.64), pulmonary (0.50), renal (0.99), and skeletal muscle tissue (0.51), following the cotinine infusion. When nicotine was infused the tissue partitioning of cotinine increased by a factor of 2.3–4.9, depending on the tissue sampled. Another group of animals were killed at timed intervals from 10 min to 30 hr, after having received a single intravenous bolus dose of 0.5 mg cotinine, and the washout of cotinine was traced in blood and tissues. A physiological model was used to simulate the disposition of cotinine. Generally, the model-predicted concentrations were consistent with those found experimentally. The fractional uptake of cotinine into various tissues was simulated. Blood, intestinal, and skeletal muscle tissues embodied more than 70% of the total body load of the drug. Clearance (Cl),volume of distribution (Vd),and the biological half-life (t1/2)were calculated both from the infusion study and by fitting a monoexponential model to the iv blood data of the rat. Significant differences were found in the apparent clearance calculated from the single iv bolus dose compared to the constant rate infusion. The volume of distribution was, however, consistent from both studies. The impact of a change in clearance was also simulated.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 110
    ISSN: 1573-8744
    Keywords: veralipride ; pharmacokinetics ; enterohepatic recycling ; double site of drug absorption
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Equal doses of veralipride have been given to 12 healthy volunteers by three different administrations-intravenous infusion, oral solution, and oral capsule-in a randomized cross-over design. After the intake of the solution, but not after infusion or capsules, two maximum plasma concentrations have been observed and interpreted, according to a double-site model for drug absorption.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 111
    Electronic Resource
    Electronic Resource
    Springer
    Journal of pharmacokinetics and pharmacodynamics 15 (1987), S. 39-55 
    ISSN: 1573-8744
    Keywords: Ajmaline ; antiarrhythmic drug ; pharmacokinetics ; pharmacodynamics ; plasma protein binding ; combined pharmacokinetic-pharmacodynamic model ; ECG
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Pharmacokinetics and pharmacodynamics of ajmaline were studied in four healthy dogs after intravenous administration of the drug at the infusion rate of 1.0 mg/min for 45 min. Ajmaline exhibited a saturable binding to plasma protein. One kind of binding site was found in the range of observed drug concentrations and its binding capacity showed nearly threefold interindividual difference. The time course of ajmaline concentration in whole blood Cbcould be described by the two-compartment open model and the unbound concentration of ajmaline in plasma Pf wasestimated from Cbby using the hematocrit value and the parameters of plasma protein binding and erythrocyte partitioning. The pharmacologic responses to ajmaline were assessed by recording ECG, and the changes in PQ and QRS interval were studied in relation to ajmaline disposition. When ECG changes were related to the ajmaline concentration, a significant degree of hysteresis was observed. The relationship between the unbound drug concentration and the pharmacologic effect was analyzed by a combined pharmacokinetic-pharmacodynamic model, where the hypothetical effect compartment is connected to the Pfin the central compartment by a first-order process. This model allows estimation of the changes in PQ and QRS intervals after intravenous administration of ajmaline. By comparing the drug effect on PQ and QRS intervals, it was suggested that ajmaline distributes to the atrial and the ventricular tissue in a similar degree and causes a reduction in the conduction rate in both sites with similar activity.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 112
    Electronic Resource
    Electronic Resource
    Springer
    Journal of pharmacokinetics and pharmacodynamics 15 (1987), S. 101-115 
    ISSN: 1573-8744
    Keywords: Lignocaine ; MEGX ; pharmacokinetics ; pharmacodynamics ; active metabolite
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Lignocaine clearance declines during continuous intravenous infustion in man and in vitrostudies suggest that this may partly be due to inhibition by MEGX, a metabolite of lignocaine, MEGX is pharmacologically active in animals, but this is not yet proven in man. This study examined the pharmacokinetics and pharmacodynamics of lignocaine and MEGX in eight healthy male volunteers given lignocaine HCl 120mg, MEGX HCl 120 mg, lignocaine HCl 120 mg+MEGX HCl 120 mg, and placebo, administered according to a randomized double-blind protocol. One-, two-, or three-compartment models were fitted to drug and metabolite blood concentration-time profiles and clearance, volume (V ss ), andhalf-life values were calculated and compared by paired t-test. Systolic time intervals and QTinterval were recorded and compared by repeated measures ANOVA. When administered in combination with MEGX, lignocaine clearance was significantly reduced from 58±18 to 48±13 L hr(su−1) (p 〈0.02). The V(inss) was unchanged and there was a trend toward an increase in terminal half-life. Lignocaine, MEGX, and the combination significantly reduced QTinterval up to 30 min after injection and this was maintained to 2 hr with the lignocaine and the combination. Transient side effects were experienced with all active treatments, but were most pronounced with the combination. Thus, lignocaine clearance was inhibited by MEGX, which was pharmacologically active in man.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 113
    Electronic Resource
    Electronic Resource
    Springer
    Journal of pharmacokinetics and pharmacodynamics 15 (1987), S. 557-568 
    ISSN: 1573-8744
    Keywords: etintidine ; propranolol ; 4-hydroxypropranolol ; interaction ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Etintidine HCl is a potent H2 -blocker. The effect of clinical doses of etintidine on the disposition of a single oral dose of propranolol was investigated in 12 normal subjects. This was a double-blind, two-way crossover study. Each subject received etintidine (400 mg) or placebo twice a day with meals for 4 days on two occasions (separated by 4 days). On each occasion, the subjects were fasted overnight on Day 3 and were given an oral dose of Inderal® (40 mg propranolol hydrochloride) 30 min following the administration of the morning dose of etintidine or placebo on Day 4. Blood samples were collected prior to and up to 24 hr following the administration of propranolol. The plasma samples were analyzed for propranolol and 4-hydroxypropranolol by HPLC. Comparison of the pharmacokinetic parameters of propranolol between etintidine and the placebo groups indicates that etintidine significantly increased the AUC0−∞,values (573.5 vs. 146.4 ng·hr/ml, p=0.0001)and prolonged the elimination half-life (4.61 vs. 2.33 hr) of propranolol. Statistical evaluation of the pharmacokinetic parameters of 4-hydroxypropanolol indicates that etintidine also increased the AUC0−24 values (43.8 vs. 16.4 ng·hr/ml, p=0.0028) and prolonged the elimination half-life (4.87 vs. 1.97 hr) of 4-hydroxypropranolol. The data suggest that etintidine, like cimetidine, impaired the elimination of propranolol. Etintidine also protracted the elimination of 4-hydroxypropranolol, an active metabolite of propranolol.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 114
    ISSN: 1573-904X
    Keywords: etretinate ; pharmacokinetics ; dose proportionality
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Twelve healthy male subjects received single oral doses of etretinate, ranging from 25 to 100 mg (1 to 4 × 25-mg capsules) in an open-label, four-way randomized crossover design. Plasma concentrations of etretinate and two active metabolites were determined by a specific high-performance liquid chromatographic (HPLC) method. Analysis of variance and orthogonal contrasts were used to assess dose proportionality. Mean (± %CV) maximum concentrations after 25- to 100-mg doses were 133 (50), 195 (33), 261 (53), and 446 (65) ng/ml, whereas AUC0−12 values were 581 (46), 1090 (39), 1500 (52), and 2440 (63) ng · hr/ml, respectively. The test for proportionality indicated that C max and AUC0−12 increased proportionally with an increase in dose (P 〉 0.05).
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 115
    ISSN: 1573-904X
    Keywords: oral cephalosporin ; cefixime ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Cefixime (CL 284,635; FK 027) is a new third-generation oral cephalosporin. To study dose-dependent pharmacokinetics of cefixime in dogs, two balanced four-way crossover studies were conducted. In the first study, oral doses of 50, 100, and 200 mg/kg and an intravenous dose of 50 mg/kg cefixime were administered. In the second study, oral doses of 6.25, 12.5, and 25 mg/kg and an intravenous dose of 12.5 mg/kg cefixime were administered to the same dogs. A period of 1 month separated the two studies. When the two intravenous doses were compared (i.e., 12.5 and 50 mg/kg), a twofold increase in clearance and volume of distribution was observed after the higher dose. The oral systemic bioavailability in the dose range 6.25–50 mg/kg was 55%. It decreased to 44% at 100 mg/kg and 27% at 200 mg/kg. The average peak serum concentrations ranged from 15.8 µg/ml at 6.25 mg/kg to 119 µg/ml at 200 mg/kg. Within this concentration range, the fraction of free drug in serum (unbound to proteins) increased from 7 to 25%. This concentration-dependent protein binding was primarily responsible for changes in total clearance, volume of distribution, and bioavailability of the drug in dogs.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 116
    ISSN: 1573-904X
    Keywords: enterohepatic recirculation ; pharmacokinetics ; bioavailability ; area under the curve ; bile ; hepatic extraction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A relationship between systemic availability and its determinants has been derived for a physiologically realistic model of drug disposition that includes enterohepatic cycling (EHC), gallbladder emptying (with an arbitrary time course), first-pass metabolism to noncycling metabolites, and fecal excretion. Systemic availability (F) has been shown to be determined by the fraction of the dose initially absorbed (f a*), the fraction of the drug excreted into the GI tract that is reabsorbed with each cycle (f a), the hepatic extraction ratio (E), and the fraction of extracted drug that is transported to the gallbladder for EHC (f g) according to the relationship F = f a*(1 −E/(1 − f a f g E) The implications of the above relationship are that (1) systemic availability is dependent on EHC, (2) values of F calculated to be greater than unity cannot be explained simply by the presence of EHC, (3) calculations of E based on the usual expression F = f a* (1 − E) are erroneous for drugs subject to EHC, and (4) a compound that has a high systemic availability and is subject to EHC is not necessarily inefficiently metabolized. The quantitative interrelationship of systemic availability and its determinants is illustrated using a contour plot. Slices through the surface are used to demonstrate that the presence of EHC changes the sensitivity of F to changes in E.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 117
    Electronic Resource
    Electronic Resource
    Springer
    Pharmaceutical research 4 (1987), S. 59-61 
    ISSN: 1573-904X
    Keywords: mean residence time ; pharmacokinetics ; Michaelis–Menten elimination ; one-compartment model
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract An equation for the mean residence time (MRT) of drug in the body is derived for the system where drug is injected intravenously into a one-compartment model and eliminated by a single, capacity-limited process. This MRT is a complex function of dose, volume, V m, and K m but degenerates into the classical volume/clearance expression under limiting low-dose conditions (K m ≫ C 0). The equation was validated by comparison of the MRT obtained by direct calculation versus numerical area estimation for simulated data. The equation may be useful analytically in the estimation of the fundamental Michaelis–Menten parameters, V m and K m, from experimental data.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 118
    Electronic Resource
    Electronic Resource
    Springer
    Pharmaceutical research 4 (1987), S. 251-254 
    ISSN: 1573-904X
    Keywords: amiodarone ; antipyrine ; desethylamiodarone ; drug metabolism ; drug interactions ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The effect of amiodarone on hepatic drug metabolism in vivo was examined in the rat using antipyrine as a model substrate. Pretreatment with oral amiodarone hydrochloride, 100 mg/kg/day, for 5 days resulted in a 19% reduction in antipyrine clearance and a 22% increase in half-life. The administration of single oral doses of amiodarone hydrochloride, 100 mg/kg, 1 or 5 hr prior to antipyrine administration had no significant effect on antipyrine pharmacokinetics. The administration of a single intravenous dose of amiodarone hydrochloride, 50 mg/kg, reduced antipyrine clearance by 32% and increased the half-life by 46%. The desethyl metabolite of amiodarone was also found to reduce antipyrine clearance (21%) after a single oral dose of 100 mg/kg.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 119
    ISSN: 1573-904X
    Keywords: computer-designed formulation ; prolonged-action dosage forms ; drug delivery systems ; long-acting formulations ; theophylline delivery systems ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The method provides an a priori assessment of the maximum allowable flexibility in the rate of release from a prolonged-release formulation. The clinical pharmacokinetic parameters describing the drug candidate are employed to calculate the ranges of rate constants and doses required for the formulation to provide a selected therapeutic duration. For a given patient, there may be an infinite number of combinations of release rate constants and dose sizes which will maintain steady-state plasma drug concentrations within a desired range when the formulation is administered at the selected dosing interval. Computer simulations of steady-state plasma concentrations are employed to establish the ranges for all of the acceptable rate constants and doses for each member of a group. The entire group is then examined to define the range of release rate constants and doses which would provide a useful formulation for every member in the group. Literature values for theophylline clinical pharmacokinetics in children and adults have been employed to illustrate the application of this method. The method is unique in that it provides an entire range of release rates on which to gauge the feasibility for success.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 120
    Electronic Resource
    Electronic Resource
    Springer
    Pharmaceutical research 4 (1987), S. 332-336 
    ISSN: 1573-904X
    Keywords: pharmacokinetics ; gold ; rabbits ; intramuscular ; intravenous ; bioavailability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Male, New Zealand white rabbits (3.5–4.3 kg) received a single 2-mg/kg dose of gold sodium thiomalate (Myochrysine) via intramuscular (N = 4) and intravenous (N = 3) routes. Blood samples were drawn from the marginal ear vein for a period of 5–10 days. The concentration of gold in whole blood was determined using graphite furnace atomic absorption spectrophotometry. The blood concentration–time profiles obtained following both routes of administration were best described by a two-compartment open model with first-order absorption for the intramuscular route. Gold was absorbed rapidly with a mean (harmonic) absorption half-life of 9.0 min, with a peak concentration of 6.0 ± 1.0 µg/ml (N = 4). Blood concentrations declined in a biphasic manner; the mean α half-lives were 0.738 and 1.78 hr for the iv and im routes, respectively. The corresponding terminal (β) half-lives were 54.1 and 63.0 hr. The estimated volume of the central compartment (70 to 93 ml/kg) agreed closely with the rabbit blood volume. The mean ( ±SD) extent of the dose absorbed following intramuscular injection was 68.9 ± 12.4%.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 121
    ISSN: 1573-904X
    Keywords: zero-order delivery ; drug delivery system ; sustained release ; computer simulation ; dosage form design ; theophylline ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Classical methods employing pharmacokinetic data to calculate zero-order release rates for sustained release products require that a constant-rate drug delivery system must have a duration which is exactly equal to the desired dosage interval. This traditional approach fails to establish the minimum acceptable duration and also fails to provide any flexibility in the formulation goal. While it does calculate one pair of duration and dose values, there are infinite pairs of values capable of maintaining the desired plasma concentrations using the selected dosing interval. In the current method, computer simulations are used to establish the boundary conditions within which any pair of duration and dose values will maintain the desired levels when administered on the chosen dosing interval. By comparing the boundary conditions for every subject in a group, a single set of conditions which would work for the entire group can be selected. These final limits represent the broadest specifications for zero-order drug delivery system design for that particular drug combined with the plasma concentration goals and the desired dosing interval. The method is illustrated using theophylline pharmacokinetics.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 122
    ISSN: 1573-7241
    Keywords: drug interactions ; digoxin ; pharmacokinetics ; antiarrhythmic drugs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary While preliminary screening for interactions between new cardiovascular pharmacotherapeutic agents and digoxin can be efficiently and safely conducted in normal healthy volunteers, it is particularly important to detect and quantify drug interactions in patients with varying degrees of cardiac, hepatic and/or renal dysfunction. Much of the previously published literature provides only minimal data to guide clinical practice because of limitations of study design including sample size and measurement techniques. Important factors that determine the ability of a particular study design to detect a drug interaction with digoxin include the accuracy and precision of the assay method for serum digoxin concentrations, intrasubject and intersubject variability in serum digoxin concentration, and sample size. The format of the trial (chronic versus single digoxin dosing in cardiac patients; chronic verus single digoxin dosing in normal subjects) and the method of assessment of alterations in digoxin handling (formal determination of digoxin clearance, comparison of multiple or single digoxin measurements during various phases of trial) also impact greatly on the clinical relevance of such investigations. Guidelines for future studies of drug interactions with digoxin in cardiac patients are proposed with particular emphasis on laboratory methods; measurement techniques during baseline, placebo, and active drug phases; calculation of the statistical power of the study; time course of the trial; and assessment of the clinical significance of the findings.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 123
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 31 (1987), S. 1-1 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 124
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 31 (1987), S. 33-44 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The theory of MCSCF and CI energy derivatives with respect to geometrical variations is briefly reviewed with special attention given to the MCSCF and MRCI energy gradients. A computational procedure is proposed for MRCI energy gradients that does not require the solution to any “coupled-perturbed MCSCF” equations, it does not require any expensive direct-CI matrix-vector products involving derivative integrals, and it does not require any derivative integrals to be transformed from the AO basis to the MO basis. An additional feature is that it does not require any changes to existing MCSCF gradient evaluation programs in order to compute MRCI gradients. The only difference in the two cases is the exact nature of the data passed to the gradient evaluation program from the previous steps in the computational procedure. The additional effort required to compute the entire MRCI energy gradient vector is approximately that required for one additional iteration of the MRCI diagonalization procedure and for one additional MCSCF iteration. For large scale MRCI wave functions, the MRCI energy gradient evaluation should only require about 10% of the effort of computing the wave function itself. This computational procedure removes a major computational botleneck of potential energy surface evaluation.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 125
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 31 (1987), S. 65-71 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Preliminary results are presented for transition probabilities in the H + H2 system derived from an adiabatic representation in terms of surface functions on hyperspheres. Special attention is given to the resonance structure for transition probabilities in the first vibrational level.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 126
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 31 (1987), S. 99-112 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Low-lying excitation energies from the ground state of Be were calculated using a basis set of 61 Cartesian Gaussian functions. Three approximations were employed: the time-dependent Hartree-Fock (TDHF), second-order equations-of-motion (EOM), and multiconfigurational time-dependent Hartree-Fock (MCTDHF). The TDHF excitation energies are 0.5-1.1 eV lower than experiment, and the EOM values are 0.3-1.2 eV lower than experiment, whereas the MCTDHF excitation energies deviate on the absolute average from experiment by only 0.03 eV. We found that in an MCTDHF calculation, any proper MCSCF stationary point is a good reference (i.e., initial) state, not just the ground state. Experimental values for oscillator strength are accurately known only for the 2s2X1S → 2s2p1P0 transition. The TDHF value and the MCTDHF value agree with experiment, but the EOM value does not. The agreement of the TDHF value with experiment seems to be coincidental, because for higher lying transitions the TDHF values differ by approximately a factor of two or more from the more accurate MCTDHF. Frequency independent polarizabilities, α(0), were also calculated with the TDHF, HRPA, and MCTDHF and frequency dependent polarizabilities, β(ω), were calculated with the MCTDHF. No experimental data for Be polarizabilities exist, but we expect the MCTDHF values to be among the most accurate calculations available.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 127
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 31 (1987), S. 941-950 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A version of the CNDO/1 method has been outlined that includes dominant relativistic effects. The method utilizes a nonempirical parametrization based on atomic Dirac-Fock calculations. The goal of this QR-CNDO/1 method lies in its applicability to molecules consisting of arbitrary atoms (z = 1-118). Applications to molecular geometries and ionization potentials for 50 molecules are presented.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 128
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 32 (1987) 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 129
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 32 (1987), S. 13-18 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: According to the formulas obtained in the preceding paper, it may be used for all types of the hybridization with any set of azimuthal quantum numbers l, l = 0 through l = 5, and a complete theoretical data of bond angles and bond strengths are shown in this paper.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 130
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 32 (1987), S. 71-86 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In the unitary-group formulation of quantum chemistry, the spin-projected, configuration-state spaces of quantum chemistry are realized by the irreducible representation spaces (IRS) of the freeon unitary group U(n), where n is the number of freeon orbitals. The Pauli-allowed IRS are labeled by the partitions [λ] = [2(N/2)-s, 12S], where N and S are the particle number and the spin, respectively. The generator-state approach (GSA) to the unitary-group formulation consists of (1) the construction of the overcomplete, nonorthonormal generator basis for each IRS; (2) the Lie-algebraic computation of matrix elements over generator states; (3) the Moshinsky-Nagel construction of the complete, orthonormal Gel'fand basis in terms of the generator basis; and (4) the computation of matrix elements over Gel'fand states in terms of matrix elements over generator states.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 131
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 32 (1987) 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 132
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 32 (1987), S. 181-191 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: It has been shown that an easier procedure to the study of molecular electrostatic potentials than the prevalent monopole isopotential approach is to use a dipole as the mapping device: allow the dipole to move on a geometrical surface enclosing the molecule such that the distance between the surface and the nearest atoms of the molecule (closest distance of approach) is fixed, say at 2 Å, calculate the electrostatic interaction energy between the molecule and the dipole at different points of the surface, and let the dipole orient itself along the minimum energy direction and treat these minimum energies as the desired electrostatic potentials. Thus the favorable binding sites of a given molecule for other species along with their relative orientations can be obtained. This procedure has been applied to the nucleic acid bases using the necessary input data from two independent sources. Thus success of the procedure in predicting important features of molecular electrostatic potentials has been demonstrated.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 133
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A systematic examination of the components of the interaction energy, obtained with the Kitaura and Morokuma method, for nine H-bonded dimers without and with counterpoise corrections (CP) is presented. The nine dimers Hn A … HBHm correspond to all the possible combinations of HF, H2O, and NH3 as electron donors and electron acceptors. The interaction energy and the corresponding components have been computed over a sizable interval of intermolecular distances with five basis sets (STO-3G, MINI-1, 3-21G, 4-31G, 6-31G**) selected among those most extensively used to study interactions in larger systems. The CP corrections to the ΔE components have been obtained with a method, implemented in our group, which permits assignment to the pertinent components of ΔE of a physically reasonable portion of the CP correction even though different CP corrections are adopted. We examine here three versions of the CP correction, namely, the full CP correction (i.e., the original version of Boys and Bernardi) and CP corrections limited to the virtual space of the partner or to the electron donor only. The resulting data are employed to assess the basis set dependence of several models of hydrogen bonding (the electrostatic model, the semiclassical model, etc.) both with and without CP corrections.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 134
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A detailed analysis of the ΔE(R) curves for nine hydrogen bonded dimers involving HF, H2O, and NH3 as partners, computed with five basis sets (STO-3G, MINI-1, 3-21G, 4-31G, and 6-31G**) and subjected to counterpoise (CP) corrections with three different methods is reported. Using several criteria and tests, the positive effect of full CP corrections for the description obtained with all the basis sets (with the exception of the STO-3G one) is pointed out. The CP correction at the 6-31G** levels is still sizable and improves the results with respect to the estimated Hartree-Fock limits of ΔE(Req) and Req. The results obtained with the application of the full CP correction to the MINI-I energies are of relatively good quality. The STO-3G energies at the SCF level are, on the contrary, overcorrected by the full CP correction and slightly improved by “limited” CP corrections: this basis set, however, is not recommended for calculations of geometries and stabilization energies of H-bonded dimers of this size.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 135
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 32 (1987), S. 295-312 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An accurate analytical electron density for the beryllium atom is obtained by using a fast and systematic method recently developed and tested for the neon atom. Asymptotic conditions both at the nucleus and at large distances are obeyed. A point-by-point comparison between our density and the one obtained from an almost “exact” configuration interaction wave function shows that differences are less than 0.5% for r between 0 and 5 bohrs and less than 1 % up to 9 bohrs. The accuracy of the density is also assessed by comparing results of density moments and x-ray scattering factors.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 136
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 32 (1987), S. 361-375 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We discuss a procedure for calculating numerical Hartree-Fock orbitals that can be applied to polyatomic systems. This approach is formulated in momentum space to avoid Coulomb singularities and uses fast Fourier transforms to solve integral convolutions. Results for a number of simple systems are presented.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 137
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 31 (1987), S. 405-415 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Binding of Zn2+ to imidazole (Im) and methyl imidazole (MeIm) is studied by ab initio methods as a model for the effect of cation binding on tautomeric energies. Gradient energy optimized conformations were obtained for all neutral and ionic structures, including the deprotonated molecules and the ylides. The N3—H tautomer of MeIm is calculated to be more stable than N1—H by about 1 kcal/mole. However, binding of a Zn2+ cation to the available nitrogen site is found to reverse the order of binding, leaving N1—H more stable by 1 kcal/mole. Binding of Zn2+ produces a significant perturbation in the electronic structure, a smaller shift in the equilibrium conformation of the imidazole ring, and only a small absolute shift in the relative tautomer energies. Methyl substitution at C5 has a small effect on both conformation and energetics.A high-energy ylide tautomer is produced by moving the proton bound to C2 to the N1 atom. The binding of Zn2+ to the C2 site is substantially stronger than to the N1 site, yielding nearly isoenergetic ZnIm2+ conformations for binding to either N or C atoms. For the deprotonated salts the lowest energy conformation has the C2—N3 bond bridged by Zn2+.
    Additional Material: 7 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 138
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 31 (1987), S. 425-427 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: It is made clear that two different statements in the literature concerning energy derivatives are completely compatible by deriving them as two different interpretations of the same equation. Some other aspects of these results are also discussed.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 139
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 31 (1987), S. 435-443 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Accurate methods for computing energies and electronic properties of atoms and molecules have been derived from direct treatment of localized pairs of electrons. The conceptual development and implementation of such methods is reviewed.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 140
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 32 (1987), S. 473-489 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The rigorous derivation of the energy density functional is proposed within the framework of the spinfree, or spin-restricted formulation of the energy density functional theory. It is shown particularly that the kinetic energy density functional is given by a sum of the Weizsacker term and the so-called “modified” Thomas-Fermi one. The variational principle is formulated for the energy density functional theory in terms of the Euler-Lagrange equation, and the virial theorem is proposed.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 141
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 32 (1987), S. 591-594 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The time-dependent Schrouml;dinger equation for the oscillator H = α(t)p2 + β(t)x2 + γ(t)x is exactly solved. The time evolution operator is easily obtained by means of an operator algebra and the quantum-mechanical equations of motion. The problem is reduced to solving the classical equations of motion. The method is shown to apply to multidimensional oscillators.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 142
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 31 (1987), S. 445-453 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A modified Bohr orbit procedure is used to calculate the energies for the 1S ground state and the 2P, 3D, and 4F excited states of the helium atom. The energies are calculated from \documentclass{article}\pagestyle{empty}\begin{document}$ {{\int\limits_0^\pi {E\left(\Phi \right)P\left(\Phi \right)d\Phi } } \mathord{\left/ {\vphantom {{\int\limits_0^\pi {E\left(\Phi \right)P\left(\Phi \right)d\Phi }} {\int\limits_0^\pi {P\left(\Phi \right)d\Phi } }}} \right. \kern-\nulldelimiterspace} {\int\limits_0^\pi {P\left(\Phi \right)d\Phi } }} $\end{document}, in which E(φ) is the Bohr orbit energy for angle φ between the position vectors \documentclass{article}\pagestyle{empty}\begin{document}$ \vec r_1 $\end{document} r1 and \documentclass{article}\pagestyle{empty}\begin{document}$ \vec r_2 $\end{document} r2, and P(φ) is a probability function for this angle. Numerical procedures are used to evaluate the integrals. Energies that range between -2.9082 and -2.9054 au are calculated for the 1S state (cf. -2.9037 au, exact). The Bohr energies for the excited states are -2.1318, -2.1240, -2.0562, -2.0555, -2.0314, and -2.0312 au, which are generally close to the exact energies of -2.1332, -2.1239, -2.0557, -2.0557, -2.0313, and -2.0313 au for the 23P, 21P, 33D, 31D, 43F and 41F states. Some relationships that exist between the Bohr theory and the Schrödinger local energies are discussed. Approximate Bohr orbit estimates for the energies of the 2P states of He, Li+,…,Ne8+ are reported.The invariance of the two-electron Bohr hamiltonian with respect to the interchange of the electron coordinates leads to two classical probability functions when the orbit quantum numbers for the two electrons differ.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 143
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 31 (1987), S. 463-470 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Valence-bond calculations are reported for the isoelectronic series of molecules and ions: N2, CO, BF, NO+ and CN-. The most important structures are N≡N, C=O, Bπ—F, N+=O and C=N. Hybridization of the 2s and 2p orbitals is important. Only two or three structures are required to obtain an energy lower than that obtained with the molecular orbital approximation. Structures in which the electronegative element loses a σ-orbital or gains a π-orbital are favored. π-bonds tend to be favored over σ-bonds. The bond in NO+ resembles that in CO, whereas that in CN- resembles the bonding in N2.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 144
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 31 (1987), S. 471-487 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ab initio SCF, CI, CEPA, and MCSCF techniques are compared and contrasted in a theoretical study of the 1s core ionized Li2 molecule from the point of view of core hole localization. In agreement with earlier studies of symmetric core ionized molecules, SCF theory is found to give a physically reasonable description of core ionization only when symmetry breaking is allowed. This results in a dramatic lowering of the energy of the core ionized state and hence of the ionization potential. By extension, CI wave functions that are developed in terms of a broken symmetry SCF reference plus its single and double excitations are found to perform significantly better than those constructed from symmetry adapted SCF orbitals. Alternatively, if the full point group symmetry is to be retained, a multiconfigurational treatment is called for and, in agreement with the conclusions of an analogous study on O2 [H. Ågren, P.S. Bagus, and B.O. Roos, Chem. Phys. Letters 82, 505(1981)], it is found that a modestly sized MCSCF wave function is capable of accounting for the energetic effects of symmetry breaking. Potential energy curves for Li2 and several states of core ionized Li2 have been calculated, allowing predictions of the adiabatic ionization potential and vibrational, satellite, and Auger structures in the photoelectron spectrum of Li2 to be made.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 145
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 31 (1987), S. 489-505 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A practical algorithm is described for generating a set of symmetry- and spin-adapted antisymmetrized products of molecular orbitals (SAAPs) which form an orthogonal basis for a full active configuration space. The spin-adaptation is completely general. The space-symmetry adaptation is accomplished for the groups C∞v and D∞v.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 146
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 32 (1987), S. 685-697 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A complete description of the rotational isomerism of monothioformic acid is presented. Ab initio results concerning the barrier heights and the energy difference between the stable isomers are in good agreement with the experimental data. A reduced potential function deduced from our calculations has been used to characterize the kinetics and thermodynamics of the rotational isomerization. The reported ab initio values of equilibrium constants are in good agreement with the experimental ones. From the analysis of the available experimental data, we have found that the free energy and enthalpy behavior are quite similar and that no noticeable entropy contributions are involved in the internal rotation, in agreement with previous studies on unimolecular isomerization processes.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 147
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 32 (1987), S. 723-723 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 148
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 32 (1987), S. 1-1 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 149
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 32 (1987), S. 85-103 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The equilibrium geometry, stabilization energy, and electric polarizability of formic acid, formamide, and the three possible cyclic hydrogen-bonded pairs are obtained by ab initio calculations using the STO-3G, 4-31G, and 6-31G** bases. These three properties are found to be very much dependent on the basis set extension. The polarizability of the dimers is found to be basically additive in contribution from the monomeric moieties.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 150
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 32 (1987), S. 133-147 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In the course of conformational motions of molecules the changes in shapes of electronic charge distributions follow that of the nuclear framework. However, this coupling between the changes in the nuclear geometry and electron density may depend on the actual nuclear displacement; the coupling may be weak or strong for a given conformational motion. It is of some interest to analyze how faithfully the charge density variations follow the nuclear displacements in a family of conformational rearrangements. In certain cases small conformational changes may induce large changes in the shape of charge density distributions, while in other cases large and qualitatively important conformational changes may involve qualitatively inessential distortions in the shape of electron distributions. In this article we describe a new classification of conformations based on those domains of nuclear configuration space within which the „shape groups“ (symmetry independent homology groups) of the electric charge density remain invariant. Such an analysis might be valuable when seeking correlations between molecular structure and certain biological or biochemical activities.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 151
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 32 (1987), S. 211-219 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Practical aspects of the calculation of the proton transfer process in a model of the active site of the thiol protease papain are explored with basis sets of different sizes. Results from ab initio calculations with the STO-3G, 4-31G, 6-31G, 6-31G* basis set, and a 6-31G basis set augmented with polarization functions on the sulfur atom are compared for their performance in describing the proton transfer energy. The nature of the convergence of the calculated properties of the potential curve for proton transfer with the increase in basis set indicates the need for a split-valence basis set and for polarization functions on the sulfur in order to achieve an appropriate description of this system. Correlation corrections to the calculated energies are shown to contribute significantly to the characteristics of the proton transfer energy curve.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 152
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 32 (1987), S. 281-288 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The scope of multistep modeling (MSM) is expanded by adding a least-squares minimization step in the procedure to fit backbone reconstruction consistent with a set of C-alpha coordinates. The analytical solution of Phi and Psi angles, that fits a C-alpha x-ray coordinate [1] is used for tyr-tRNA synthetase. Phi and Psi angles for the region where the above mentioned method fails, are obtained by minimizing the difference in C-alpha distances between the computed model and the crystal structure in a least-squares sense. We present a stepwise application of this part of MSM to the determination of the complete backbone geometry of the 321 N terminal residues of tyrosine tRNA synthetase to a root mean square deviation of 0.47 Å from the crystallographic C-alpha coordinates.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 153
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 32 (1987), S. 325-330 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We have examined an application of the weighted identification number in the QSAR study of the toxicity of aliphatic ethers on mice. The results obtained are superior to those achieved by the connectivity index.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 154
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 32 (1987) 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 155
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 32 (1987), S. 13-14 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 156
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 32 (1987), S. 89-97 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ab initio self-consistent-field electronic state calculations have been carried out for an interstitial-iron-substitutional-boron impurity pair complex in silicon. The calculations do not provide support for the currently accepted microscopic ionic model for the pair. Rather, we have shown that the covalent effects play a basic role in determining the physical properties of the complex.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 157
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 32 (1987), S. 115-129 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: By analyzing the convergence properties of the lattice sums in the exchange part of the restricted Hartree-Fock orbital energy, we isolate the source of the nonanalytic behavior of a partially occupied band at the Fermi energy. This analysis shows how an extended system behaves qualitatively differently from a finite system but also provides a possibility of following the development of nonanalyticity as the size of the system grows.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 158
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 32 (1987), S. 163-170 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The aromatic (A) and quinoid (Q) forms of polythiophene (PT) have entirely different energy gaps: ∼0.5 eV for the quinoid form and ∼2 eV for the aromatic form, respectively. The energy gaps and stability of derivatives of PT are studied by total MNDO geometry optimization using energy band theory for the total energy calculations followed by a Hückel energy band calculations to approximate the energy band structure. Addition of fused rings to PT reverses the order of stability of the aromatic and quinoid isomers and the ordering in the size of the energy gaps. Small energy gap polymers are suggested on the basis of the calculations.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 159
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 32 (1987), S. 191-198 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Chemical reactions and conformational changes of N-atom systems can be described as displacements in a (3N-6)-dimensional metric configuration space M provided with a global metric. Although space M has a metric, it is not in general a vector space; it is a topological space. In contrast to the commonly used internal configuration spaces based on bond length/bond angle internal coordinates, and having no global metrics, within space M each internal configuration of the nuclei of the molecule corresponds to one and only one point of the space. This property of M is advantageous when analyzing chemical reactions. The global metric of M ensures that differences between any two internal configurations can be interpreted as a distance in this space that allows one to provide M with coordinate systems by turning M into a manifold with boundary. Certain formal reaction paths show some counterintuitive behavior within this space: they may undergo a formal reflection at some points of M. A condition, the tangent criterion, is used for the diagnosis of such reaction paths and for the determination of special nuclear configurations where such reflections occur.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 160
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 31 (1987), S. 649-662 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Energies and geometries for a number of small hydrogen bonded dimers have been calculated by semiempirical method based on a perturbation approach. Results have been compared with experimental and the best theoretical data. A quite good description of equilibrium configurations has been obtained in every case when local multipoles from sufficiently accurate wave functions have been used. Hydrogen bond lengths have not been predicted with sufficient precision. Results indicate, however, that it should be possible to achieve improvement in the framework of the applied calculation scheme by modification of the parameter values.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 161
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 32 (1987), S. 283-295 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We examine the photoaddition of hydroxylazoaromatic compounds and related thione analogs with olefins. By examining the properties of the lowest lying singlet and triplet states, we conclude that the product distribution is best described by the unpaired spin density of the triplet state. This suggests that absorption of light by the aromatic is followed by conversion into the triplet, and this triplet is the active precursor. Since unrestricted molecular orbital calculations are easily performed on the lowest triplet of these aromatics, prediction of possible products is straightforward.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 162
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 32 (1987), S. 267-282 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Hydrogen addition to acetylene has been studied by molecular orbital methods with the unrestricted Hartree-Fock (HF)approach and with Møller-Plesset (MP) perturbation theory up to fourth order using the 6-31G*, 6-31G**, and 6-311G** basis sets. For each basis set a number of points along an approximate reaction path were calculated by fixing the attacking H—C distance and optimizing all of the remaining parameters. At these geometries, single point MP4 calculations with and without spin projection were carried out, yielding the position, height, and shape of the addition barrier at the various levels of calculation with each of the three basis sets. The results of this approach were confirmed by a grid search of the region near the transition state using the 6-31G* basis set. The unprojected MP2, MP3, and MP4 barriers are too narrow and are 10-20 kcal/mol too high. With spin projection, the barriers are much lower and broader. At the PMP4SDTQ/6-311G** level, with zero point energy calculated at UHF/6-31G*, the vibrationally adiabatic barrier at 0 K is 4.0 kcal/mol, and the attacking H—C distance is 2.0 Å.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 163
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 32 (1987), S. 313-319 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We explore the implications of static disorder on electron transfer (ET) in a microscopically inhomogeneous polar medium, where the environment of each solute is characterized by a single dielectric relaxation time, τ, with the distribution function of τ being related to the complex dielectric susceptibility. For the interesting situation of solvent-controlled ET, the decay of the population probability is nonexponential, which can be expressed in terms of a cumulant expansion. The microscopic decay function can be related to the macroscopic step-response function of the dielectric medium.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 164
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 32 (1987), S. 355-362 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A self-consistent model capable of describing the interaction of a metal electrode/liquid electrolyte interface is presented. As in a real system, a capacity maximum shifted towards positive charges is obtained from the model. The metal is represented by the planar uniform background model (jellium). The solvent is described by a polar liquid whose response to charge is accounted for in terms of the local approximation. The interaction between the metal and ions is modelled by a charged plane placed near the metal surface. Charge neutrality of the whole system is preserved. The present model is a good approximation for highly concentrated solutions.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 165
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 31 (1987), S. 733-737 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In this paper we outline briefly how microlocal analysis can be applied to give a general approach to the mathematical theory of resonances in the semiclassical limit. We also describe recent results about the asymptotic behavior of resonances generated by closed trajectories and stationary points in the classical flow.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 166
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 31 (1987), S. 739-746 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In this paper we make explicit constructions of a family Aθ of intertwining operators between the Schrödinger operator Hv = -Δ + v(x) and H0 = -Δ. The wave operators and the scattering matrix are expressed in terms of the Aθ, and some methods of inverse scattering are described.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 167
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 31 (1987), S. 707-731 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Examples from music and nuclear, as well as atomic and molecular, physics are given to introduce and illustrate the resonance concept. Some fundamental concepts of scattering theory such as the differential and the total cross section are presented. The concept of the collision complex is illustrated with a light particle scattering reaction in nuclear physics. The concept of channels is introduced, and this formalism (which is so far empirical in nature) is dressed in the language of quantum mechanics. Finally I show that our descriptions of phenomena in nuclear physics can also be used in atomic and molecular physics.
    Additional Material: 18 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 168
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The analytic energy gradient method that we have recently implemented for CCSD wave functions is applied to fully optimize the pyramidal C3v and planar D3h structures of ammonia. Using a double-zeta plus polarization basis set, results for harmonic vibrational frequencies, infrared intensities, and dipole moments have been obtained. Comparison with different levels of truncated configuration interaction suggests that CCSD values are of better than CISD quality and generally closer to CISDTQ results.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 169
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 32 (1987), S. 539-545 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Effective core potentials are utilized in conjunction with polarization propagator calculations of excited state properties. The propagator method employed is based on an antisymmetrized geminal power wave function as the reference state. Calculations are presented on the low-lying excited states of HF and NaH. All-electron and valence-electron results are compared for HF. The choice of basis set is found to be very important for obtaining good results.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 170
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 32 (1987), S. 569-572 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The nonadiabatic energy correction term of the hydrogen molecule at large separation is discussed to determine whether or not the nuclear motion induces the inter-atomic interaction potential. Nonadiabatic vibrational motion of nuclei induces the internal charge polarization of atoms to give the novel correction term to the London R-6 force. The correction term is (4/M) (1/R3), which is important at large R despite the overwhelming magnitude of nuclear mass.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 171
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 31 (1987), S. 755-794 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: As an extension of the recent atomic work of Krylstedt et al. [1, 2], we propose the synthesis of the static exchange plus polarization model within the multiple scattering Xα formalism and the exterior complex rotation method for the study of shape resonances occurring in molecular collisional systems. The bound state multiple scattering Xα method is reviewed with special attention to the form of the various wave functions for the different molecular regions. In connection with the inclusion of continuum electron exchange into the scattering model, we analyze a possible solution to the problem of asymptotical behavior caused by the local density-based free electron gas approximation used in this case. We also propose a method to fix the cutoff parameter, inherent in the polarization potential, for symmetry-related molecular participants in the scattering process, thereby obtaining a possible predictive power for the one-parameter scattering model.Titchmarsh-Weyl's theory is used to formally connect the above formulation to scattering theory. The theoretical difficulties in obtaining a unique meromorphic continuation of the S matrix are investigated in connection with the requirements on the actual potential to be exterior dilation analytic. Furthermore, the occurrence of asymptotic quantum numbers is noted and discussed in conjunction with muffin tin-like approximations and related exterior complex rotated schemes.It is found that the electron exchange part of the nonstatic one-body potential exhibits a functional form that is not exterior dilation analytic, albeit the general electron and nuclear many-body problem involving Coulomb forces are dilation analytic. Although the immediate consequences indicate a rotation angle (θ) dependence on the S matrix continuation, a uniquely defined assignment of the cutoff parameter r0 = r0(θ) makes the present nonstatic model “exterior dilation analytic” in the sense that it mimics the dilation analytic structure of the full many-body problem at the same time obeying “asymptotic” spherical symmetry via the associated constant of evolution. However, in the static exchange approximation the above difficulties are shown to be circumvented via a certain reformulation, leading to a regular analytic asymptotic form for the interaction potential.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 172
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 31 (1987) 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 173
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 31 (1987), S. 841-845 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In the present article we show how the bound states of the Coulomb potential may be associated with resonances that occur when this potential is perturbed by a barrier potential. The main idea is to trace the bound states on successive switching on of the barrier perturbation. It is found that those bound states that are localized inside the barrier are highly sensitive to variation with respect to the barrier height, whereas those that are localized outside are less sensitive. However, there are certain intervals for the barrier height when the role of being “a state localized inside the barrier” is shifted from one bound state to another. The result can be pictured as a “relay race,” where the “deliveries of the baton” are carried out over corresponding avoided crossings. The baton is ultimately handed over to a shape-type resonance state.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 174
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 31 (1987), S. 847-853 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Methyl substitutents located peri to bay-region benzo rings of polycyclic aromatic hydrocarbons generally reduce or eliminate carcinogenic activity, most likely because such substituents force the hydroxyl groups of dihydrodiol intermediates to adopt preferentially pseudodiaxial, rather than pseudodiequatorial, conformations. Empirical force field calculations have been employed to examine the influences of peri and other positional substituents on hydroxyl conformation, taking naphthalene, anthracene, and phenanthrene as model compounds. For the unsubstituted naphthalene and anthracene dihydrodiols, the pseudodiequatorial conformation is preferred. This preference is reduced by adjacent methyl substitution and reversed by peri methyl substitution. Because of steric crowding the phenanthrene bay-region dihydrodiol preferentially adopts a pseudodiaxial conformation. The results are discussed in relation to recent experimental evidence.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 175
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 31 (1987), S. 855-869 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The electronic absorption spectra of some phenylethylamine drugs, namely, d-pseudoepherine, l-pseudoephedrine, l-ephedrine, dl-ephedrine dl-norephedrine, phenylethylamine, methoxyphenamine, and l-noradrenaline were investigated in polar and nonpolar solvents. The observed transitions were interpreted, and the role of σ-π interaction was explored. Molecular orbital calculations were performed on representatives of the above group of compounds, namely, d-pseudoephedrine, l-ephedrine, and l-noradrenaline using the INDO procedures and adopting the best conformer of the molecule. The transition energy, band intensity, and dipole moments were calculated and corresponded satisfactorily with the experimental values.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 176
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 31 (1987), S. 893-901 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The analytic expressions of the integral prototypes involving both Slater and s-type Gaussian functions, explicity derived in Ref. 1, are generalized to the case of higher order modified Gaussian functions [2].
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 177
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: By expanding the wave function of a system of N particles in terms of products of functions of one and (N-1) particles, the one-particle, nonlocal operator F̂EKT (extended Koopmans' theorem) is determined. It is shown that although this operator is nonhermitian, its eigenvalues and eigenfunctions represent the ionization energies and occupied orbitals, respectively. The eigenfunctions of F̂EKT are the one-particle functions that enter into the expansion of the wave function of the system as partners of the (N-1)-particle wave functions. The eingenvalues are also one-particle energies that, multipled by the orbital occupancy probalities, enter the expression for the total N-particle energy of the system.
    Additional Material: 7 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 178
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 31 (1987), S. 927-939 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We apply completely transferable, strictly localized molecular orbitals for the calculation of molecular electrostatic fields. This approach, derived from our previous bond fragment method for the calculation of molecular electrostatic potentials, reduces computational efforts drastically. The fields around small molecules containing first- and second-row atoms are systematically overestimated as compared with ab initio calculations with a minimal STO-3G basis set. However, deviations can be corrected by a simple multiplicative factor, which means that the overall shape of the potential and field around the molecule is correctly reproduced. Our approximate field can be used to determine possible hydration sites around molecules as proposed earlier by Peinel and coworkers. Application of the method is illustrated on the formamide molecule.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 179
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 32 (1987), S. 399-399 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 180
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 32 (1987), S. 403-403 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 181
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 32 (1987), S. 427-434 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The quality measure δ of Sordo and Pueyo is computed for 94 orbital basis sets for the atomic helium Hartree-Fock problem and compared with various information theoretic quality measures reported previously by us for this data base. δ is in error often enough that it is unlikely to be a useful general purpose measure.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 182
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 32 (1987), S. 457-466 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The Sturmian transformation is reviewed and some of its properties are discussed, in particular, its use in perturbative approaches, its connection with variational schemes, and its use for the study of resonances. One potential problem (Doolen) having no bound states is described exactly.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 183
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 32 (1987), S. 27-35 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Basis set and correlation effects on computed hydrogen bond energies of the negative ion complexes AHn · AHn-1-1, for AHn = NH3, OH2, and FH, have been evaluated. The addition of diffuse functions on nonhydrogen atoms to valence double- and triple-split plus polarization basis sets [6-31G(d, p) and 6-311G(d, p)] significantly decreases binding energies by 9-19 kcal/mol, depending on the particular complex and the level of theory. Adding diffuse functions to hydrogens has a negligible effect, while replacing the single set of polarization functions on each atom by two sets alters energies by 1 kcal/mol or less. Electron correlation increases the hydrogen bond energies of these complexes and has a greater effect for basis sets without diffuse functions. Since the Hartee-Fock energies computed with these basis sets are already too large, correlation energy calculations should not be performed in these cases. For basis sets including diffuse functions, the correlation energy contribution to the binding energies of these complexes is significant, with the Møller-Plesset second-order term being the largest term and having a stabilizing effect of from 3-6 kcal/mol. The third and fourth order terms are smaller, and may be of opposite sign. As a result, the MP2 and MP4 energies differ by no more than 1 kcal/mol, with the MP2 stabilization energy being greater except for N2H5-1. The computed standard solvation enthalpy of OH-1 by H2O based on either MP4/6-311 + G(2d, 2p) or MP2/6-31 + G(d, p) electronic energies is -26.8 kcal/mol, in excellent agreement with a recent gas-phase experimental measurement.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 184
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 32 (1987), S. 105-110 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new definition of molecular similarity in terms of electron density is proposed and a method for calculating similarity based on molecular electrostatic potential and molecular electric field introduced. It is applied to some simple isosteres.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 185
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 32 (1987), S. 127-132 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Most of the important conformations of biomolecules possess only trivial symmetry. Consequently, symmetry groups have no roles in the characterization of the shapes of such conformations. However, an alternative group theoretical model, based on homology groups of algebraic topology, provides a detailed description of shapes for all conformations. These shape groups are useful for precise comparison of molecular shapes and are proposed as a computational tool for QSAR. A new computational method for the determination of various shape groups is described which is suitable for the simultaneous analysis of a pair or a family of molecular properties. In this note a general method is described and applied to the shape of electronic charge distribution along van der Waals surfaces.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 186
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 32 (1987), S. 189-209 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Studies on the proton transfers in water clusters (H2O)n (n = 2, 3, 4, 5, 6), and in DNA base pairs, adenine-thymine base pair, and guanine-cytosine base pair, have been done by using the potential functions of polarization model for water and ab initio SCF method with STO-3G basis set for base pairs, respectively.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 187
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 32 (1987), S. 261-280 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Briefly noting earlier studies on the polypentapeptide of elastin, (Val1-Pro2-Gly3-Val4-Gly5)n, and on elastin, it is emphasized that entropic elastomeric force can be exhibited by nonrandom, anisotropic polypeptide systems and therefore that entropic elastomeric force does not necessarily result from isotropic random chain networks as required by the classical theory of rubber elasticity, nor does it result from solvent entropy effects as deduced from the slow loss of elastomeric force on thermal denaturation. Instead entropic protein elasticity can be the result of internal chain dynamics, specifically of librational processes that become damped on chain extension. This new mechanism of entropic protein elasticity allows for an understanding not only of elastin but also of the passive tension of striated muscle, of the voltage-dependent interconversion between open and closed conductance states in the sodium channel of squid nerve, and of protein elastic forces producing strain in a substrate bond during enzyme catalysis. Because entropic elastomeric force develops as a result of an inverse temperature transition, it becomes possible to shift the temperature of the transition to higher or lower temperatures by decreasing or increasing, respectively, the hydrophobicity of the elastomeric polypeptide chain. In warm-blooded animals this allows for biochemical modulation of the relaxation or development of entropic elastomeric force by an enzymatically modulated decrease or increase of the hydrophobicity, as for example, by phosphorylation or dephosphorylation of the elastomeric polypeptide chain. This understanding provides a mechanism for modulating protein function, whether for example enzymatic or channel, a mechanism for the remarkable reversible structural processes that attend parturition, and a mechanism for the connective tissue anomalies of wound repair and enviromentally induced lung disease.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 188
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 32 (1987), S. 297-315 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We have recently discovered a new entirely unexpected, and highly selective protein - ligand interaction. This new kind of molecular interaction was recognized by chromatography of proteins on divinylsulfonated agarose gels which had been deactivated using mercaptoethanol. The essential structure of the interacting immobilized ligand is quite simple and nonionic. It can be generally represented by: \documentclass{article}\pagestyle{empty}\begin{document}$$\hbox{agarose-O-CH}_2 \hbox{CH}_2\hbox{-SO}_2\hbox{-CH}_2\hbox{-X-}$$\end{document} where X was first a thioether but can also be N, O(S 〉 N ≫ O) or possibly any atom with at least one lone electron pair. We have provisionally termed peptides and proteins interacting with this ligand „thiophilic,“ in recognition of their affinity for the definitive thioether sulfone constituents. The thiophilic adsorption process is promoted by water-structuring or „antichaotropic“ salts such as sulfates or phosphates and would appear to be entropically driven. The thermodynamics of such a process are discussed relative to protein recognition of the immobilized thioether-sulfone ligand. We do not yet know the precise mechanism for the interaction but we believe that salt allows the protein into close contact with the immobilized thioether-sulfone group where short-range forces are likely to be important. Evidence suggests that aromatic side chains on the protein-binding site may be involved and we therefore expect that some kind of electron-donor-acceptor or proton-acceptor mechanism is likely involved. Two important applications of thiophilic adsorption are the selective immobilization of functional antibodies as well as purification of immunoglobulins from serem, ascites fluid, and hybridoma cell culture media. Monoclonal antibodies can be purified in one step under extremely mild (structure-stabilizing) conditions. We therefore consider the further characterization of thiophilic adsorption of major significance in the fields of immunology and biotechnology and hope that this presentation will inspire attempts to explain the interaction in terms of quantum chemistry.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 189
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 32 (1987), S. 347-349 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 190
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 32 (1987), S. 15-29 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An attempt is made to analyze the present state of first-principles methods used in solid state theory to elucidate where these methods derive their strength and why they may be expected to gain even more predictive power in the near future. The latter will depend on the success of recently contemplated improvements. As regards the ground state properties of solids, there are two - in principle -  rigorous ways of treating the associated N-electron problem. One is based on the Hohenberg-KohnSham (HKS) theory, which maps the electronic pair correlation onto a strictly local, energy-independent potential that occurs in the associated one-particle equations. The alternative approach, which will not be discussed in this paper, is connected with determining quasi-particle amplitudes from the Dyson equation, where the information on the electronic pair correlation is absorbed into a nonlocal energy-dependent self-energy operator.Distinctly different from HKS theory, which only applies to ground states, the quasi-particle scheme lends itself to describe excitations (e.g., interband transitions) just as well. We shall furthermore discuss a generalization of the HKS theory that explains why naive extensions of this approach to excited states have been relatively successful in a variety of cases.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 191
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 31 (1987), S. 73-80 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A band intensity alternation has been observed in the absorption spectra to the à 1A2″ state of NH3 and ND3 cooled in supersonic expansions. The nuclear statistical explanation for this interesting effect is given here.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 192
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 31 (1987), S. 113-117 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In a recent paper [5], Ford, Lewis, and O'Connell proposed a remarkable formula for the change in the free energy in terms of the susceptibility alone. This formula came out of their treatment of a quantum oscillator interacting (via dipole coupling) with a blackbody radiation field at finite temperature T. As a result, they found a modification to the Planck formula due to finite line width and a positive energy shift which is of quantum electrodynamical origin.I shall show in this paper that the above result is a general one, not specific to the problem considered, and whose essence can already be traced to the early works of van Kampen and Liftshitz on the theory of van der Waals forces, Maradudin et al. on point defects in lattices, and Mahanty and others on dispersion forces. The above formula can be deduced directly using the argument theorem in theory of contour integration.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 193
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Cellular spin resonance (CSR) or electrorotation is the spinning of cells or other particulate matter in rotating electric fields. The spin rate of the (bio)particle varies markedly with the applied frequency and often is seen to have rather sharp maxima as the frequency is varied. In certain frequency ranges, living cells often are observed to undergo a striking inversion of their spin rate and then spin counter-clockwise (CCW) while the direction of rotation of the applied electric field is clockwise (CW).The CSR spectra are presumably due to dipolar interactions with the applied field, as are the spectra obtained by straightforward dielectrophoresis (DEP) techniques. The two spectra, however, differ radically in the low frequency ranges (below about 1 MHz). It is our objective to explain this apparently anomalous behavior.We believe that the anomaly appears primarily because one is comparing rotational with translational force responses. In the DEP techniques, the simpler translational force arising from the comparative polarizability of cell versus medium (water) gives a straightforward measure of the differential polarizability owing to volume and surface effects pro forma. In the CSR techniques the spin rate reflects the torque on the cells and hence emphasizes polarization at the outer periphery of the cells rather than that of the average overall polarizability.The problem is considered in terms of a living or dead cell rotating with an angular velocity Ω in a fluid medium of viscosity η when it is subject to an electric field rotating at angular frequency ω. It is observed in many experiments that Ω ≪ ω, and also that the sign of Ω for the same cell can change from CW to CCW and back to CW as the applied frequency ω of the CW electric field is increased. Moreover, the sign and magnitude of the CSR spectra differ for living and dead cells. All of these experimental results can be explained quantitatively by using Maxwell's equations and the dielectric properties of a lossy dielectric sphere in an ionically conductive dielectric fluid.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 194
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 32 (1987), S. 105-122 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The fermion unitary group formulation (UGF) of many-body theory is based on the unitary group U(2n) where n is the number of freeon orbitals. This formulation, which conserves particle-number but not spin, is isomorphic to the particle-number-conserving, second-quantized formulation (SQF). In UGF we derive the familiar diagrammatic algorithm for matrix elements, M(Y) = (-1)H+L where H and L denote the numbers of hole lines and loops in the diagram D(Y) of M(Y). The unitary group derivation is considerably simpler than is the conventional, second-quantized derivation that employs time-dependence, Wick's theorem, normal-order, and contractions. In neither fermion UGF nor SQF is spin conserved. We carry out in UGF the spin-projection (symmetry adaptation to SU(2)) of the fermion vectors and obtain with a spin-free Hamiltonian the same matrix elements as with the freeon UGF (part 24 of this series). The fermion unitary group formulation for a spin-free Hamiltonian should be regarded as an alternate path to spin-free quantum chemistry.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 195
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 32 (1987), S. 149-164 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The Hartree-Fock (HF) equations for the (He)2 system are solved using a suitable exchange perturbation technique. The HF interaction energy is then obtained directly from a rapidly convergent iteration procedure. The method remains convergent for short interatomic distances, where the interaction energy surpasses the energy of intraatomic excitations. The fast convergence of the method is a result of the proper treatment of the exchange-deformation effects. In the region of the van der Waals minimum, these effects account for 50% of the HF deformation energy.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 196
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 32 (1987), S. 249-264 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The algorithm to derive symmetry orbitals for one-electron band-structure calculations of one-dimensional crystals presented by Božović and Delhalle [1] has been applied to extend the explicit formulation of symmetry-adapted linear combinations of Bloch sums to any line group isogonal to Cn or Cnv. We also point out how the transformation matrices that block-diagonalize the one-electron eigenvalue equation H(k)C(k) = S(k)C(k)E(k) can be determined. Finally, the extended-Hückel block-matrix dimensions of some typical quasi-one-dimensional transition metal compounds have been tabulated in order to give a measure for computational savings achievable by this technique.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 197
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 32 (1987), S. 511-516 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The SCF method for the calculation of energy levels of triatomic molecules is applied using the hypervirial perturbative procedure for solving the coupled equations. This treatment allows to obtain in a recursive way the energy corrections and the expectation values required in the SCF treatment, avoiding the explicit calculation of the wave functions. A numerical application is made to the SO2 and O3 molecules, comparing our results with those obtained by other methods.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 198
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 32 (1987), S. 517-545 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Similarity measures between pairs of molecular wave functions are described. They are based on the geometrical structure of the LCAO-MO framework and upon multivariate analysis ideas. The theoretical framework is presented, and formulae for some integrals needed are given. Two main measures, distance and correlation coefficients, are used. Distance and correlation matrices induce relationships in the whole MO set, which can be depicted through minimal spanning tree techniques. Furthermore, principal component analysis allows a two-dimensional visualization of the Mo manifold geometrical relationships. Various examples are given in order to obtain information on how basis set, environment, excitation, bending, stretching, and electronegativity affect the induced order. For this purpose “ab initio” SCF-LCAO-MO calculations with double- and single-zeta quality basis sets have been used for various simple molecular structures: H2O, NH3, CH4, N2, O2, C2, NO, CN, and CO. The results obtained can open the way to LCAO-MO taxonomy. Using this information, other areas of interest are connected with similarity measures (SCF and CI, localization procedures, etc.), proving in this manner their potential utility.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 199
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 32 (1987), S. 547-547 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 200
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 32 (1987), S. 663-667 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The upper and lower bounds of a harmonic oscillator with an octic perturbation are studied with the use of renormalized inner projection. It is shown that this relatively simple technique works even in the infinite coupling constant limit. Symbolic computation is very convenient and useful in these types of problems, where only a finite number of operations are required.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...