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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 86 (1999), S. 6462-6467 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The electrical characteristics of metal–oxide–semiconductor capacitors with SiON/Ta2O5 gate dielectric stacks with thin Ta2O5 layers (6–10 nm) are investigated. From the field and temperature dependence of the current of the gate stacks, it is shown that the main conduction mechanism at low bias is tunneling through the stack and that Poole–Frenkel conduction in the Ta2O5 layer becomes important at larger bias and temperature. From the analysis of the data in the high voltage and temperature range, taking into account the field distribution in both layers, the refractive index n of Ta2O5 and the energy level φB of traps involved in Poole–Frenkel conduction are found to be 2.3 and 0.85 eV, respectively. It is also shown that the gate current density of the stack is reduced by one to three orders of magnitude as compared to SiO2 layers with equivalent electrical thickness (2.5–3 nm). The temperature acceleration effect on the time-dependent dielectric breakdown is shown to be much reduced in the SiON/Ta2O5 stack as compared to SiO2 layers with equivalent electrical thickness. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 84 (1998), S. 4351-4355 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The current–voltage characteristics of metal-oxide-semiconductor capacitors with a 4.2 nm SiO2 gate oxide are investigated. After the occurrence of soft breakdown, which is observed during constant current stress of the devices, the gate current is shown to behave like a power law of the applied gate voltage. We propose that this power law behavior is due to the formation of a percolation path between the electrons traps generated in the SiO2 layer during current stress of the capacitor. We describe a simple model which accounts for the current–voltage characteristics between two neighbor trapping sites, as well as a distribution of percolation thresholds in these (finite size) ultrathin SiO2 layers. The prediction of the model is in fair agreement with the experimental results in a large voltage range, and leads to a better description of the data than previously reported models. Furthermore, it is shown that this percolation model can also explain the temperature dependence of the gate current after the occurrence of soft breakdown. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 77 (1995), S. 1323-1325 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The surface reactivity of hydrogen-passivated, HF-last-cleaned Si(100) toward aqueous HX and HF/HX (X=Cl, Br, I) is examined. The HCl and HBr solutions are found to leave the HF-cleaned bare Si surface unaltered, while the HI solution reoxidizes the hydrogen-passivated surface. Treatments in aqueous HF/HCl or HF/HBr solutions lead to the same surface passivation and surface microroughness as for HF-cleaned surfaces. In the HF/HI solution, a simultaneous oxidation and etching process takes place, resulting in an increased (111) microfaceting of the Si(100) surface. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 73 (1998), S. 514-516 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The dielectric breakdown under constant current stressing of 4.2 nm SiO2 gate oxides is investigated. After soft breakdown, which corresponds to an anomalous increase of the stress-induced leakage current of metal–oxide–semiconductor capacitors, the current behaves like a power law of the applied gate voltage VG. After soft breakdown, charge is further injected into the SiO2 layer in order to extract the effective resistivity ρeff of the system as a function of the density of oxide traps D generated in the layer. It is found that ρeff behaves like a power law of (D−Dc) where Dc is the critical density of traps generated at soft breakdown. These results are in fair agreement with the predictions of the percolation theory of nonlinear conductor networks. Besides, the value of the critical exponent related to the resistivity is close to the one expected in two dimensions. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Surgical and radiologic anatomy 20 (1998), S. 197-201 
    ISSN: 1279-8517
    Keywords: Portal system ; Mesenteric veins ; Portal vein ; Splenic vein ; Abdominal injuries
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The gastrocolic v. or Henle’s gastrocolic trunk was described in 1868 [9]. We suggest defining this vein as the confluence of the right gastroepiploic and right upper colic vv. We report two original cases of avulsion of the gastrocolic v. occurring during a blunt abdominal trauma. The aim of this paper is a description, based on the literature, of the anatomy of the gastrocolic v. in order to precise the lesional mechanism. The gastrocolic v. is present in 70% of individuals. It is short (less than 25 mm) but of major calibre (3 to 10 mm). The gastrocolic v. is situated close beneath the root of the transverse mesocolon, and travels along the anterior surface of the head of the pancreas. Anatomic variations are detailed and a meta-analysis of interpretable studies was made. Both the supra- and infra-mesocolic surgical approaches are described. The radiologic and surgical importance of the gastrocolic v. is discussed. The lesional mechanism in both our cases of injury of the gastrocolic v. is explained.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Surgical and radiologic anatomy 20 (1998), S. 197-201 
    ISSN: 1279-8517
    Keywords: Portal system ; Mesenteric veins ; Portal vein ; Splenic vein ; Abdominal injuries
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé La description de la v. gastrocolique (vena gastrocolica) ou tronc gastro-colique de Henle remonte à 1868. Nous proposons de définir la v. gastrocolique comme résultant de la confluence de la v. gastro-épiploïque droite et de la v. colique supérieure droite. Nous rapportons deux observations originales d'arrachement de la v. gastro-colique au cours d'un traumatisme fermé de l'abdomen. Le but de ce travail est de décrire, à partir d'une revue de la littérature, l'anatomie de la v. gastrocolique afin de préciser le mécanisme lésionnel. La v. gastrocolique existe chez 70% des individus, c'est une veine courte (moins de 25 mm) et de calibre important (3 à 10 mm). La v. gastro-colique est située immédiatement en dessous de la racine du mésocolon transverse, et longe la face antérieure de la tête du pancréas. Les variations anatomiques sont détaillées et une méta-analyse des études interprétables a été réalisée. Les deux voies d'abord chirurgicales sus- et sous-mésocoliques sont décrites. L'intérêt radiologiqut et chirurgical de la v. gastro-colique est discuté. Le mécanisme lésionnel dans les deux observations de lésions traumatiques de la v. gastrocolique est expliqué.
    Notes: Summary The gastrocolic v. or Henle's gastrocolic trunk was described in 1868 [9]. We suggest defining this vein as the confluence of the right gastroepiploic and right upper colic vv. We report two original cases of avulsion of the gastrocolic v. occurring during a blunt abdominal trauma. The aim of this paper is a description, based on the literature, of the anatomy of the gastrocolic v. in order to precise the lesional mechanism. The gastrocolic v. is present in 70% of individuals. It is short (less than 25 mm) but of major calibre (3 to 10 mm). The gastrocolic v. is situated close beneath the root of the transverse mesocolon, and travels along the anterior surface of the head of the pancreas. Anatomic variations are detailed and a meta-analysis of interpretable studies was made. Both the supra- and infra-mesocolic surgical approaches are described. The radiologic and surgical importance of the gastrocolic v. is discussed. The lesional mechanism in both our cases of injury of the gastrocolic v. is explained.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-1076
    Keywords: Childhood respiratory symptoms ; Respiratory impedance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A cross-sectional study was conducted to evaluate possible interregional differences in respiratory health in primary school children living in two different towns of the Netherlands, Melick/Herkenbosch Asenray (MHA) (n=511) and Leek (LK) (n=612). The prevalence of respiratory symptoms was determined by means of a questionnaire and respiratory impedance was measured using the forced oscillation technique (FOT). Respiratory symptoms were reported consistently more often in MHA than in LK; chronic cough (17% MHA vs 5% LK), shortness of breath (15% vs 8%), wheeze (16% vs 13%) and attacks of shortness of breath with wheeze (10% vs 7%). However, doctor-diagnosed asthma was reported as 7% in MHA and 6% in LK. The prevalence rates expressed as odds ratios of MHA versus LK were all 〉1 even when adjusted for known indoor environmental factors. Living in MHA appeared to be a statistically significant determinant of the reported symptom prevalence. Furthermore, the child's age, maternal smoking (〉 10 cigarettes/day), and having had domestic animals were positively associated with one or more respiratory symptoms. Calculating adjusted differences in respiratory impedance between the regions resulted in a small but statistically significant difference in resonant frequency, LK being slightly at a disadvantage. Measured outdoor air pollution levels of SO2, NO2, O3 and PM10 were in general higher in MHA. In both regions however, the average levels remained below the present WHO guidelines, except for NO2 in MHA where the guideline was slightly exceeded. Conclusion In this study prevalence rates of key symptoms of asthma were found to be significantly higher in children living in one region of the Netherlands (MHA) compared to another (LK). Known (indoor) risk factors for respiratory disease could not explain the observed differences in symptom prevalence between the regions. However, statistically but not clinically significant interregional differences in respiratory impedance values were found between children living in MHA and children living in LK. Further research will have to incorporate techniques to evaluate the potential influence of information bias.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1432-8798
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary.  Genetic relationships between the genome segments of six cypovirus (CPV) isolates were analysed by RNA cross-hybridisation. These included three type 1 viruses and single isolates of types 2, 5 and 12, which collectively are identical to those previously compared by serology and electrophoresis [Mertens et al. (1989), J Gen Virol 70: 173–185]. Since only genome segment 10 of three cypovirus types and segments 8 and 9 of a single virus strain (of type 1) have currently been sequenced, this initial study provides some additional information on sequence variation / similarity in each of the ten genome segments. The RNA of the type 1 viruses showed high levels of cross-hybridisation. Significant but much lower levels of cross-hybridisation were detected between type 1 and the related type 12 CPV. However, only very low levels of cross-hybridisation were detected between the other pairs of viruses. Apart from evidence of a slightly higher level of sequence similarity between the largest segments, the RNA sequence appeared to vary uniformly across the whole genome. There was no evidence for any type specific RNA sequences restricted to individual genome segment(s). The sequence variation, reflected in the levels of RNA sequence similarity and cross hybridisation, correlates well with serological data, showing large differences between CPV types and supports the continued use of electropherotype as one of the ‘species parameters’ for the classification of cypoviruses.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1432-8798
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary.  Transmission of bluetongue virus (BTV) by a vector species of Culicoides was studied using immunohistochemistry, virus titration and in vitro transmission tests. Adult female C. variipennis were used from two colonies that are either “transmission competent” or “transmission refractory” after oral infection with BTV. Intrathoracic (IT) injection of BTV into the haemocoel always resulted in a fully disseminated infection and transmission of virus in saliva. However, after ingestion of an infectious blood meal, only 30% (approximately) of midges from either colony became persistently infected. Although none of the orally infected insects from the “refractory” colony were able to transmit virus, 12% of those from the “competent” colony (containing ≥ 103.0TCID50 of virus/midge) did transmit BTV in their saliva. The most important barriers to BTV transmission in Culicoides vector species appeared to be a mesenteron infection barrier (MIB), which controls initial establishment of persistent infection, a mesenteron escape barrier (MEB) which can restrict virus to gut cells and a dissemination barrier (DB) which can prevent virus which enters the haemocoel from infecting secondary target organs. Culicoides variipennis do not appear to present either a salivary gland infection barrier (SGIB), or a salivary gland escape barrier (SGEB) to BTV.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical microbiology & infectious diseases 18 (1999), S. 242-247 
    ISSN: 1435-4373
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. An epidemic of pertussis is described among elderly people in a religious institution in the Netherlands in 1992. Subjects were evaluated for their vaccination status and for history and presence of respiratory symptoms. Specimens were collected for culture, polymerase chain reaction, and serological evaluation. None of the 75 residents and 19 of 24 nonresident personnel had been vaccinated against pertussis. The overall attack rate of clinical pertussis, defined as persistent cough lasting at least 2 weeks, was 49%. In five subjects with clinical pertussis, either culture or polymerase chain reaction or both were positive for Bordetella pertussis. A significant (at least 4-fold) change in specific antibody titre was observed in 85% (41/48) and 20% (10/49) of subjects with and without clinical pertussis, respectively (P〈0.0001, chi-square 41.1). The attack rate of laboratory-confirmed pertussis was 42% (41/98). This rate was 5% (1/19), 20% (1/5), and 53% (39/74) in vaccinated personnel, nonvaccinated personnel, and nonvaccinated residents, respectively (not significant). Among residents aged between 55–74 years and 75–94 years, the attack rates were 47% (17/36) and 58% (22/38), respectively (relative risk=0.8; 95% confidence interval 0.5–1.3). Four of 75 residents (5%) died from intracranial bleeding, while they were symptomatic for pertussis. It is concluded that the attack rate of pertussis was high among nonvaccinated elderly and that pertussis tended to increase with age. There may be a considerable risk of mortality from pertussis in this population. Physicians should be alert to the diagnosis of pertussis in the elderly with nocturnal and prolonged periods of coughing.
    Type of Medium: Electronic Resource
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