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  • 1990-1994  (10)
  • 1994  (7)
  • 1992  (3)
  • 1
    Electronic Resource
    Electronic Resource
    Scattering mechanisms and defects in InP epitaxially grown on (001) Si substrates (1994)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 76 (1994), S. 4705-4712 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Carrier concentration and mobility of unintentionally doped InP layers, grown directly on Si using metal-organic vapor-phase epitaxy, have been studied. The formation of antiphase domains (APDs) was found to depend on annealing of the Si substrate in an AsH3 flow prior to epitaxial growth. Dislocation densities determined by the wet chemical delineation technique were (8±1)×107 cm−3, seemingly uncorrelated to APDs in the layers. In addition to a shallow donor and a compensating acceptor, a deep donor was observed affecting the temperature dependence of the free-electron concentration between 77 and 300 K. The electron mobility in this temperature range could be described in terms of the scattering mechanisms which are dominant in homoepitaxial InP, namely, scattering due to polar optical phonons, to ionized impurities, and to space charges. Electron scattering due to either of these mechanisms was strongly influenced by the occurrence of antiphase boundaries (APBs). The space-charge density as well as the degree of compensation of the epitaxial layers increases with the density of APBs. Degraded 300 K mobilities were obtained indicating the effect of local stress at the APB.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.358445
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  • 2
    Electronic Resource
    Electronic Resource
    Computer controlled probe diagnostic system and applications in a magnetized laboratory plasma (1994)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 65 (1994), S. 2615-2622 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A computer controlled acquisition and evaluation system for electrostatic probes is presented. Fully automatic evaluation of the probe characteristics yields electron temperature, plasma potential, and density during the recording. Two-dimensional probe positioning is accomplished with stepping motors. The system is characterized by 12-bit probe current resolution and extremely wide probe voltage range (±130 V). It is tested in a collisionless argon magnetoplasma and compared to standard wave diagnostic techniques for magnetized plasmas, i.e., the resonance cone technique. The influence of the probe radius on the electron current in a magnetized plasma is studied experimentally. The two techniques yield identical density and temperature values within 20% accuracy and therefore show the reliable applicability of the automatic evaluation system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1144660
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Distribution of serum IgE in children and adolescents aged 7 to 16 years in Copenhagen, in relation to factors of importance (1992)
    Oxford, UK : Blackwell Publishing Ltd
    Allergy 47 (1992), S. 0 
    Details
    ISSN: 1398-9995
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The distribution of total serum-IgE and factors of importance for the level of IgE was studied in a random sample of 508 children and adolescents, aged 7–16 years, from Copenhagen. A detailed history about asthma, rhinitis, dermatitis and urticaria was obtained, and a physical examination, skin prick test with 9 common allergens, lung function test, bronchial challenge with inhaled histamine and exercise, and measurement of IgE (kU/1) were performed. The distribution of IgE among children and adolescents was found to exhibit a log normal distribution and a positive skin prick test, allergic symptoms, a family history of allergic diseases, age and smoking were found to be significantly related to an increased level of IgE. No relationship was found between increased bronchial responsiveness and IgE. The geometric mean of “normal” values of IgE (* 1 SD and *2 SD) of the Danish children and adolescents was 18 kU/1 (*4.7, * 18.2), suggesting that normal IgE values were within 330 kU/1. Measurement of IgE as the only screening for allergic disease is unreliable, as the predictive value of an elevated IgE in population samples was found to be 50%, whereas misclassification (1-specificity) of asymptomatic subjects as allergic because of an increased IgE was low (4%). In conclusion, total IgE is highly influenced by allergen skin reactivity. Further, this study suggests that normal IgE values were within 330 kU/1, although the range was wide.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1398-9995.1992.tb00669.x
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  • 4
    Electronic Resource
    Electronic Resource
    Electronic degrees of freedom and unimolecular rate constants in metal clusters (1994)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 101 (1994), S. 10481-10484 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: We calculate the modifications of the unimolecular rate constants for free metallic clusters due to thermally exited electronic degrees of freedom. The effect is essentially taken into account by substituting Helmholtz's free energy of the electronic system for the ground state energy. The activation energy pertaining to the electronic ground states of the mother and daughter cluster is then replaced by the first difference in Helmholtz's free energy. © 1994 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.467866
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  • 5
    Electronic Resource
    Electronic Resource
    Timber structures in seismic regions RILEM state-of-the-art report (1994)
    Springer
    Materials and structures 27 (1994), S. 157-184 
    Details
    ISSN: 1359-5997
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02473030
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  • 6
    Electronic Resource
    Electronic Resource
    Circadian variation of blood pressure in patients with diabetic nephropathy (1992)
    Springer
    Diabetologia 35 (1992), S. 1074-1079 
    Details
    ISSN: 1432-0428
    Keywords: Type 1 (insulin-dependent) diabetes mellitus ; diabetic nephropathy ; ambulatory blood pressure ; circadian ; variation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The association between diurnal blood pressure variation and diabetic nephropathy was assessed in four groups of Type 1 (insulin-dependent) diabetic patients who underwent 24-h ambulatory blood pressure monitoring using an oscillometrie technique. Patients with nephropathy, who had never been treated for hypertension (group D3,n = 13), were individually matched for age, sex and diabetes duration to a group of microalbuminuric patients (D2,n = 26), to normoalbuminuric patients (D1,n = 26) and to healthy control subjects (C,n = 26). Group D3 was also compared to patients with advanced nephropathy receiving treatment for hypertension, mainly a combination of angiotensin converting enzyme inhibitors, metoprolol and diuretics (D4,n = 11). In group D3 24-h diastolic blood pressure (85 ± 8 mm Hg) was comparable to the results obtained in D4 (85 ± 8 mm Hg) but significantly higher than in D2 (78 ± 7 mm Hg), D1 (73 ± 7 mm Hg) and C (73 ± 7 mm Hg,p 〈 0.05, Tukey's test). The night/day ratio of diastolic blood pressure was higher in D3 (86 ± 5 %) and D2 (85 ± 7%) than in C (80 ± 7 %,p 〈 0.02). This ratio was also elevated in group D4 (94 ± 8%) compared to D3 (p 〈 0.05) corresponding to a marked smoothing of the diurnal blood pressure curve. The 24-h heart rate (beats per min) was significantly elevated in D3 (84 ± 8) and D2 (80 ± 10) compared with C (73 ± 11,p 〈 0.05 Tukey's test), suggesting the presence of parasympathetic neuropathy In conclusion the normal circadian variation of blood pressure was moderately disturbed in a group of microalbuminuric patients and patients with less advanced overt nephropathy. Patients with advanced diabetic nephropathy receiving antihypertensive therapy showed a marked reduction of nocturnal blood pressure fall, which can only be identified by the application of ambulatory blood pressure measurements to verify the 24-h effectiveness of blood pressure control.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02221684
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  • 7
    Electronic Resource
    Electronic Resource
    Management of Peutz-Jeghers syndrome (1994)
    Springer
    International journal of colorectal disease 9 (1994), S. 177-179 
    Details
    ISSN: 1432-1262
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé Les patients danois porteurs d'un syndrome de Peutz-Jeghers sont enregistrés dans le registre danois des polyposes. Nous avons débuté un nouveau programme de follow-up en nous basant sur les données récentes de la littérature et sur nos propres cas. Le suivi a été ajusté sur la vitesse de croissance des polypes alors que chez les patients asymptomatiques et qui présentaient un taux de croissance lent, les contrôles ont pu être espacés. Le programme comporte des endoscopies hautes et basses du tractus gastro-intestinal, un transit baryté suivi et, dans certains cas, chez des porteurs de polypes étendus ou asymptomatiques, une laparotomie a été réalisée avec une entéroscopie pertopératoire totale complétée par des polypectomies. Un examen de la cavité pelvienne, un frottis cervical, une palpation du sein et des testicules ont été réalisés chez toux les patients âgés de plus de 30 ans.
    Notes: Abstract Danish patients with Peutz-Jeghers syndrome are registered in the Danish Polyposis Register. We have initiated a new follow-up programme based on recent literature including our own cases. This has been adjusted to the regrowth rate of the polyps whereby patients with no symptoms and low regrowth rate are followed with few examinations. The programme includes upper and lower gastrointestinal endoscopy, small bowel enema and in cases with large or symptomatic polyps, laparotomy with intraoperative total enteroscopy with polypectomy as required. Pelvic examination, cervical smear, breast and testicular examination are carried out after the age of 30 years.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00292244
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  • 8
    Electronic Resource
    Electronic Resource
    Reduced glomerular filtration rate and cardiovascular damage in diabetes: a key role for abnormal albuminuria (1992)
    Springer
    Acta diabetologica 29 (1992), S. 201-213 
    Details
    ISSN: 1432-5233
    Keywords: Abnormal albuminuria ; ACE-inhibition ; Hypertension ; Microalbuminuria ; Diabetic nephropathy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract There is general agreement that a fall rate in glomerular filtration rate (GFR) is the principal endpoint in diabetics with renal disease, and that abnormal albuminuria (including microalbuminuria) is an important intermediate end-point. The relative roles of blood pressure (BP) elevation and abnormal albuminuria in the prediction and genesis of renal disease are a matter of debate, and are further analysed in this paper. New studies show that neither genetic predisposition to hypertension (parental BP) nor parental abnormal albuminuria can be used to predict renal disease in patients with type 1 (insulin-dependent) diabetes. However, parental predisposition to proteinuria seems to be important to certain types of patients with type 2 (non-insulin-dependent) diabetes. Cross-sectional as well as follow-up studies document that GFR is generally well preserved in microalbuminuria (in both type 1 and type 2 patients), while the transition to clinical proteinuria is associated with a decline in GFR. Thus, prevention of overt proteinuria is important in clinical trials in microalbuminuric patients. In type 1 diabetes clear ultrastructural changes have been documented with microalbuminuria and a good correlation between abnormal albuminuria and structural damage is seen. Structural damage in normo- and microalbuminuric patients correlates poorly with BP. New studies in type 1 diabetes document that microalbuminuria (but not elevated BP) predicts not only clinical diabetic nephropathy but also end-stage renal failure and mortality. In type 2 diabetes microalbuminuria is the strongest predictor of mortality, whereas BP elevation is not a predictor. Several studies now document that antihypertensive treatment, especially with inhibitors of angiotensin converting enzyme, is able to reverse or reduce abnormal albuminuria, even in non-hypertensive type 1 patients, and possibly preserve GFR. Therefore, microalbuminuria may be the main indicator for starting antihypertensive treatment in these patients. With respect to organ damage in the retina, abnormal albuminuria is an important indicator of the risk of severe diabetic retinopathy. BP elevation seems not to be an initiating factor, but rather aggravates established retinopathy. Left ventricular hypertrophy has a stronger correlation with BP elevation than normoalbuminuria, suggesting that left ventricular hypertrophy is at least partially a phenomenon secondary to elevated BP in diabetic patients with abnormal albuminuria. Generally, abnormal albuminuria is a strong indicator of cardiovascular renal damage in diabetic patients and in most organs is a stronger factor than elevated BP.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00573489
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  • 9
    Electronic Resource
    Electronic Resource
    Shubnikov-de Haas effect and effective mass inn-InP in dependence on carrier concentration (1994)
    Springer
    The European physical journal 95 (1994), S. 281-285 
    Details
    ISSN: 1434-6036
    Keywords: 71.25.T ; 71.25.J
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Shubnikov-de Haas investigations onn-InP are presented and the effective mass as a function of carrier concentration is determined. The experiments are carried out with bulk and liquid phase epitactically grown material and carrier concentrations betweenn=1017 and 1019cm−3. Temperatures employed ranged fromT=2 to 77 K and magnetic fields were applied up toB=22 T. Supplementing Kane's theory by introducing both temperature and electron concentration dependence, the nonparabolicity of the effective mass for temperatures betweenT=0 K and 300 K is calculated. The result fits quite well to the experimental results.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01343953
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  • 10
    Electronic Resource
    Electronic Resource
    Kaon interferometry in heavy-ion collisions at the CERN SPS (1994)
    Springer
    The European physical journal 64 (1994), S. 209-217 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract K+K+ and K−K− correlations from S+Pb collisions at 200 GeV/c per nucleon and K+K+ correlations from p+Pb collisions at 450 GeV/c per nucleon, are presented as measured by the focusing spectrometer of the NA44 experiment at CERN. Multidimensional fits are performed in order to characterize the kaon-emission volume, which is found to be smaller than the pion-emission volume.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01557392
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