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  • 1
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 70 (1997), S. 3455-3457 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report the observation of tunneling induced transparency in asymmetric double quantum well structures. Resonant tunneling through a thin barrier is used to coherently couple the two upper states in a three level system of electronic subbands in a GaAs/AlGaAs structure. This creates Fano-type interferences for the collective intersubband excitations in the absorption from the ground state, analogous to electromagnetically induced transparency (EIT) in atomic systems. We observe a 50% reduction in absorption between the subband resonances which can be explained by taking into account the coherent coupling of the upper states. We analyze the bias dependent absorption spectra and determine the relevant lifetime broadening and dephasing rates for the transitions. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 149 (1997), S. 0 
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: A cosmid library of enterohemorrhagic Escherichia coli (EHEC) O157:H7 strain EDL 933 was constructed and clones carrying the stx2 gene were identified by colony blot hybridization with a stx2B specific probe. Nucleotide sequencing upstream of the stx2A gene revealed high sequence identities of 89.5% to the ileX tRNA gene found in E. coli. The ileX gene was located 260 bp from the translational start codon of stx2A. PCR analysis with primers specific for this analyzed region showed that in 11 Stx2-producing EHEC strains from patients with hemolytic uremic syndrome, all PCR-positive strains carried the ileX tRNA gene. However, PCR analysis of the respective region in 11 Stx1-producing EHEC strains detected no ileX genes. Although the role of ileX in Stx2-producing EHEC strains is not clear, its function in regard to the use of rare codons and as an integration site is discussed.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Der Chirurg 68 (1997), S. 279-282 
    ISSN: 1433-0385
    Keywords: Key words: Intermuscular lipoma ; Intramuscular lipoma ; Infiltrating lipoma ; Treatment ; Diagnosis. ; Schlüsselwörter: Intermusculäres Lipom ; intramusculäres Lipom ; infiltrierendes Lipom ; Diagnose ; Therapie.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung. Intramusculäre Lipome sind seltene benigne Tumore, die wegen ihres nicht abgrenzbaren Wachstums auch als infiltrierende Lipome bezeichnet werden und tief lokalisiert die Skelettmuskulatur befallen. Klinisch imponiert als einziges Symptom eine palpable Raumforderung. Mikroskopisch findet sich zwischen den Muskelfasern monovacuoläres Fettgewebe, welches die Myocyten verdrängt. Im Extremfall kann die präexistente Muskulatur völlig durch Fettgewebe ersetzt werden. Eine sorgfältige pathohistologische Untersuchung aus einer repräsentativen Biopsie ist notwendig, um die Verwechslung mit einem gut differenzierten Liposarkom zu vermeiden. Die verspätete Diagnosestellung, die Ausdehnung und die Lokalisation des Tumors lassen R0-Resektionen oft nicht zu und beeinflussen die Rezidivraten, die zwischen 3 und 62 % angegeben werden [4]. R0-Resektionen sind in Fällen, bei denen postoperativ bedenkliche Funktionsverluste zu erwarten sind, nicht anzustreben. Funktionsstörungen werden langsam eintreten und können weitgehend kompensiert werden, im Gegensatz zu einem sofortigen Funktionsverlust nach radikaler Chirurgie.
    Notes: Summary. Intramuscular lipomas are rare, benign unencapsulated tumors. They are also called infiltrating lipomas because of their infiltrative growth pattern which, deeply localized, seizes the skeleton muscle. The only obvious symptom is a palpable mass. Microscopically, monovacular fat tissue shows up between the muscle fiber. In extreme cases the preexisting muscle can be totally replaced by fat tissue. A precise pathohistological examination is needed to avoid the mistaken diagnosis of a well-differentiated liposarcoma. Late diagnosis, the extent and the localization of the tumor often do not allow for an R0 resection and influence the postoperative recurrence rates, which lie between 3 and 62 %. R0 resections are not desirable when postoperative severe loss of function can be expected. Malfunctions will slowly take place and can greatly be compensated, in contrast to a radical procedure with immediate loss of function.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1433-0407
    Keywords: Schlüsselwörter Basilaristhrombose ; Ethik ; Locked-in-Syndrom ; Sterbehilfe ; Intensivmedizin ; Lebensverlängernde Therapie ; Key words Basilar Artery Thrombosis ; Ethics ; Locked-In Syndrome ; Euthanasia ; Intensive Care ; Life-Support Care
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Decisions regarding the extent of treatment of severely ill patients can be an ethical dilemma when life-prolonging intensive care contradicts the goal of avoiding unnecessary suffering on the part of the patient. Here we present the results of a written survey of physicians on neurological intensive care units in Germany regarding the treatment of patients with basilar artery thrombosis and locked-in syndrome. 52% of the 93 physicians who replied advocated not treating severe infections with antibiotics. 38% were in favor of stopping intensive care. In contrast, 55% recommended intubating the patient in the presence of swallowing disturbances and imminent aspiration. 58% were in favor of discussing these problems in detail with the patient, and 87% advocated discussing them with relatives. Nearly all physicians (97%) recommended using adquate amounts of opiates and benzodiazepines. In very rare cases, 99% would agree to the use of passive ethanasia and 19% to active euthanasia. These findings illustrate the current disagreement on some of the important treatment decisions among physicians on neurological intensive care units. An open exchange of views on these questions could facilitate the appropriate consideration of ethical matters in the treatment of these patients.
    Notes: Zusammenfassung Entscheidungen über das Ausmaß der Therapie schwerkranker Patienten können ein ethisches Dilemma sein, wenn die Forderung nach lebensverlängernden intensivmedizinischen Maßnahmen der Absicht entgegensteht, unnötige Belastungen der Patienten zu vermeiden. Wir berichten Ergebnisse einer schriftlichen Umfrage unter den Ärzten neurologischer Intensivstationen in Deutschland zur Behandlung von Patienten mit einer Basilaristhrombose und einem Locked-in-Syndrom. Von den 93 Ärzten, die geantwortet hatten, sprachen sich 52% für den Verzicht auf eine antibiotische Behandlung im Falle einer schwerden Infektion aus. 38% befürworteten die Einstellung aller intensivmedizinischen Behandlungsmaßnahmen. Demgegenüber würden 55% den Patienten erneut intubieren, sofern die Gefahr einer Aspiration besteht. Diese Entscheidungen sollten nach Meinung von 58% detailliert mit dem Patienten, nach Meinung von 87% detailliert mit den Angehörigen besprochen werden. Fast alle Ärzte (97%) sprachen sich jedoch für eine ausreichende Medikation mit Opiaten und Benzodiazepinen aus. In besonders ausgewählten Einzelfällen würden 99% eine passive und 19% eine aktive Sterbehilfe befürworten. Diese Ergebnisse zeigen, daß es derzeit in bezug auf einige der relevanten Therapieentscheidungen keinen Konsens unter den Ärzten neurologischer Intensivstationen gibt. Ein offenerer Meinungsaustausch hierüber könnte helfen, die vielfältigen ethischen Aspekte bei der Behandlung dieser Patienten angemessen zu berücksichtigen.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Monatshefte für Chemie 128 (1997), S. 475-491 
    ISSN: 1434-4475
    Keywords: 2,4-Dioxohexahydro-1,3,5-triazin ; Mannich reaction ; N-Alkylation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary 2,4-Dioxohexahydro-1,3,5-triazin (DHT) reacts with formaldehyde and secondary amines (Mannich reaction) to the corresponding 1,3,5- or 1,5-aminomethyl-DHTs (1a–8a or1b–11b).DHT and formaldehyde give the methylol compounds12a,12b, and12c. Alkylation ofDHT with alkyl halides in presence of base and dimethyl-sulfoxide as the solvent affords the tri-N-alkyl derivatives14–22. 1,5-Dimorpholinomethyl-DHT (1b) can be alkylated in position 3 with alkyl halides. The morpholinomethyl groups in positions 1 and 5 behave as protecting groups and are easily removable. Thus, it is possible to introduce different alkyl substituents into the molecule. The reaction of1b with dihaloalkanes results in a coupling of twoDHT moleculesvia the nitrogen in position 3 (compounds26–29).
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1600-5767
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences , Physics
    Notes: Small-angle X-ray scattering (SAXS) is generally not applicable to thin ( ̃1 μm) films and coatings because of their weak scattering signal in conventional transmission experiments. This restriction can be overcome by working in grazing incidence, with an angle of incidence α slightly above the critical angle of total reflection φc, in order to augment the effective X-ray path in the sample. The possibilities of this technique are demonstrated by preliminary results obtained on glass-like sol-gel coatings containing nano-scaled gold colloids. The scattering of the gold colloids was identified by variations of the X-ray energy near the absorption edge of gold (anomalous SAXS). It showed the theoretically predicted variation of intensity with energy. The recorded scattering spectra were corrected for absorption and refraction effects, whose influences on the spectra are discussed. Calculated size distributions of the colloids from SAXS in grazing incidence were compared with results from high-resolution transmission electron microscopy (HTEM) investigations and optical UV-visible spectroscopy.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-055X
    Keywords: Schlüsselwörter Inhalationsanästhesie ; Sevofluran ; Kosten-Effektivitätsanalyse ; Kostenkontrolle ; Key words Anaesthetics ; Inhalation ; Sevoflurane ; Cost-effectiveness ; Cost control
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Abstract The economic impact of the new German health care laws requires an awareness of cost-effectiveness when using newer drugs. The main goal in patient care, i.e., effective treatment, must be achieved by the rational use of restricted resources at a maximum degree of effectiveness. Economic aspects of the new inhalational anaesthetics such as sevoflurane are discussed in this article. The cost of inhalational anaesthetic agents accounts for up to 5% of all the running expenses of an anaesthesia department. The consumption and cost of an inhalational agent depend on fresh gas flow, vapour setting, and duration of anaesthesia. Comparing the cost for 1 MAC-h of anaesthesia, desflurane is more expensive at current market prices than sevoflurane and isoflurane. However, at low or minimal fresh-gas flows, the price for one MAC-h is almost the same for these volatile anaesthetics. Total intravenous anaesthesia using propofol is even more expensive, partly due to wastage, i.e., opened ampoules with a remainder of propofol that has to be discarded after each case. When choosing an anaesthetic agent, the price of 1 ml liquid anaesthetic is an important factor. However, the overall cost-effectiveness analysis must balance the cost of the agent with its pharmacodynamic advantages such as more rapid recovery from anaesthesia. Furthermore, the indirect costs of side effects have to be taken into account. For example, nausea and vomiting lead to a prolonged stay in the recovery room after anaesthesia for outpatient surgery, which in turn incurs additional costs for antiemetic drugs and the extra time for nursing care. Therefore, a lower incidence of nausea and vomiting and a more rapid recovery from anaesthesia leading to earlier discharge from the recovery room may compensate for the higher price. Volatile agents account for up to 1% of the total intraoperative costs. In analysing the costs of 1 h of anaesthesia, other products such as plasma substitutes and blood products account for a much higher proportion than anaesthetic agents, and reductions or increases in costs pertaining to these products have a bigger impact on overall costs than do volatile anaesthetics. We conclude that volatile anaesthetics account for only a minor portion of the anaesthesia department budget and the cost of anaesthesia delivery. The higher market price of the new agents may be compensated for by the economic impact of fewer side effects and a shorter post-anaesthesia stay in the hospital. In analysing data for sevoflurane, this agent may be cost-effective, for example, for outpatient anaesthesia.
    Notes: Zusammenfassung Die veränderten ökonomischen Bedingungen aufgrund des Gesundheitsstrukturgesetztes machen Kosten-Effektivitätsanalysen bei der Einführung neuer Medikamente erforderlich. Das Hauptziel der Patientenversorgung, nämlich die effektivste Behandlung, muß unter maximaler Effizienzsteigerung angesichts der beschränkten Ressourcen erreicht werden. Am Beispiel der modernen Inhalationsanästhetika, insbesondere des Sevofluran, werden die für den Anästhesisten ökonomisch relevanten Aspekte dargestellt. Inhalationsanästhetika verursachen nur ca. 5% der Sachkosten einer Anästhesieabteilung. Die Kosten für eine einzelne Inhalationsanästhesie hängen neben den Einkaufskosten für diese Substanzen im wesentlichen von dem Frischgasfluß, der Vaporeinstellung und der Anästhesiedauer ab. Beim Vergleich einer MAC-Stunde ist bei den aktuellen Preisen die Inhalationsanästhesie mit Desfluran teurer als die mit Sevofluran oder Isofluran, wobei sich jedoch unter low- und minimal-flow Bedingungen die Kosten annähern. Die Kosten für das Inhalationsanästhetikum betragen bis zu 1% der intraoperativen Kosten einer Fallpauschale. Andere Faktoren wie z.B. die Personalkosten oder die Sachkosten für Plasmasubstitute oder Blutprodukte sind für höhere Kostenanteile verantwortlich, so daß sich Einsparungen oder Mehrkosten in diesen Bereichen wesentlich stärker auswirken als bei dem Kostenfaktor Inhalationsanästhetikum. Eine Kosten-Effektivitätsanalyse am Beispiel der Inhalationsanästhetika muß nicht nur den Einkaufspreis der jeweiligen Substanz, sondern die Gesamtkosten mit einschließen, die durch unterschiedliche Nebenwirkungen oder differente postnarkostisch notwendige Überwachungszeiten bedingt sind. Am Beispiel des Sevofluran kann nach den bisherigen Daten für einige Einsatzgebiete wie z.B. die ambulante Tageschirurgie errechnet werden, daß dieses Inhalationsanästhetikum aufgrund der kürzeren notwendigen Betreuung im Aufwachraum trotz des höheren Einkaufspreises kosteneffektiv ist.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Zeitschrift für Lebensmittel-Untersuchung und -Forschung 205 (1997), S. 158-164 
    ISSN: 1431-4630
    Keywords: Key words Adulteration ; Carbon-13 ; Citric acid ; Ethanol ; Malic acid ; Tartaric acid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract  The δ13C-values of organic acids and their correlations to those of the sugar and ethanol, respectively, from 57 EU data bank wines of the Rheinpfalz area (years 1991 – 1993) and from some of their corresponding musts have been determined. In addition to the well established difference between fermented sugar and ethanol (Δδ13C = –1.7±0.2‰), a new constant correlation was found in wine for ethanol and citric acid (Δδ13C = +2.4±0.4‰). From this result a fixed δ-value difference for citric acid in wine to the fermented sugar of +0.7±0.6‰ can be deduced. The δ13C-values of L-malic acid and L-tartaric acid in must were not altered by the alcoholic fermentation; they should therefore directly provide access to the δ13C-value of the natural sugar in must. However, in non-adulterated wines the expected δ13C-value differences between these acids and ethanol showed unsatisfactory correlation coefficients. For L-malate this is attributed to the secondary (partial) degradation of this acid by the malolactic fermentation; a corresponding correction is envisaged in order to make L-malate available as an internal standard. As a reason for the unsatisfactory correlation between L-tartaric acid and ethanol, it is supposed that the time of its maximum biosynthesis period does not coincide with that of glucose in the grape ripening period.
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  • 9
    ISSN: 1432-2242
    Keywords: Key words Brassica napus ; Collinearity ; Desaturation ; Fatty acid ; Genetic mapping
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  This paper reports the estimated gene copy number and restriction fragment length polymorphism (RFLP) map locations of five different desaturase cDNA clones from Brassica napus (oilseed rape). The desaturase enzymes encoded by four of these genes catalyze successive reactions that insert double bonds into lipid-linked fatty acid residues. Delta-12 (e2) and delta-15 (e3) desaturases are active in the endoplasmic reticulum, while omega-6 (p2) and omega-3 (p3) desaturases catalyze analogous desaturation reactions via a parallel pathway located in plastids. The fifth cDNA clone (b5) contains a desaturase-like domain bound to a cytochrome b5 segment. Estimates of gene copy number based on Southern blot analysis of 16 oilseed rape varieties and three different resynthesized Brassica napus lines indicated that e2 had 4–6 gene copies and e3, p2, p3 and b5 each had 6–8 gene copies per haploid genome. Estimates of the gene copy number for the two progenitor species, Brassica oleracea and Brassica rapa, supported the premise that all these genes were at least duplicated or triplicated in the two progenitor species before they combined to form B. napus. RFLP mapping results showed that the e2 probe detected 4 distinct loci, the e3 probe 6 loci and p2, p3 and b5 each detected 8 loci, with pairs of loci often mapping to homoeologous regions on 2 different linkage groups. The 28 mappable loci were distributed across 12 linkage groups of the B. napus map (Parkin et al. 1995) and were usually represented by single RFLP fragments. A collinear segment containing the e2 and p3 loci was positioned on B. napus linkage groups N1, N11, N3, N13, N5 and N15. This segment was collinear with a 30-cM region of Arabidopsis thaliana chromosome 3 that contains the homologous fad2 (e2) and fad7(p3) genes. This suggests that the desaturase multigene families arose as the result of duplication of large chromosome segments rather than duplication of individual genes.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Der Radiologe 37 (1997), S. 426-431 
    ISSN: 1432-2102
    Keywords: Key words Necrotizing enterocolitis ; Pneumatosis intestinalis ; Portal venous air ; Pneumoperitoneum ; Abdominal radiograph ; Sonography ; Computed tomography ; Schlüsselwörter Nekrotisierende Enterokolitis ; Pneumatosis intestini ; Pneumoportogramm ; Pneumoperitoneum ; Abdomenübersichtsaufnahme ; Sonographie ; Duplexsonographie ; Computertomographie
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die nekrotisierende Enterokolitis ist eine schwere abdominelle Erkrankung des Säuglings in den ersten beiden Lebensmonaten. Die Frühzeichen auf der Röntgenaufnahme des Abdomens sind Distension der Darmschlingen primär im Dünndarm, sekundär auch im Kolon, und die Pneumatosis intestini. Die Pneumatosis intestini ist nicht pathognomonisch für die nekrotisierende Enterocolitis, sie kann in allen Lebensabschnitten bei unterschiedlichen abdominellen Erkrankungen auftreten. Sie kann sowohl Hinweis auf eine abdominelle Ileussituation sein als auch bei klinisch nicht akut kranken Patienten auftreten. Zur radiologischen Diagnostik im Kindesalter wird eine Abdomenübersichtsaufnahme in Rückenlage, bei Verdacht auf eine Perforation zusätzlich in linker Seitenlage durchgeführt. Die Sonographie und die Duplexsonographie erlauben eine zusätzliche Aussage zur Schwere der Erkrankung, zum Krankheitsverlauf und zur Differentialdiagnose.
    Notes: Summary Necrotizing enterocolitis is a serious abdominal disease in infants during the first 2 months of life. The earliest radiographic finding on frontal abdominal films is initially distension of the small bowel, secondly of the colon, and pneumatosis intestinalis. Pneumatosis intestinalis is not pathognomonic for necrotizing enterocolitis; it can occur throughout life in different abdominal diseases. It can be a serious prognostic sign for abdominal ileus, but it may also occur in non-critically ill patients. Radiographic diagnosis in childhood is achieved with a frontal film of the abdomen in the prone position, and to detect a possible perforation, a left lateral abdominal decubitus exposure is necessary. Sonography and duplex sonography are helpful in evaluating progressive changes, the clinical course and the differential diagnosis.
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