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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 82 (1997), S. 2359-2364 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: (Ba,Sr)TiO3 (BST) thin films grown by chemical vapor deposition and with platinum (Pt) top and bottom electrodes have been characterized with respect to the leakage current as a function of temperature and applied voltage. The data can be interpreted via a thermionic emission model. The Schottky approximation accounts for superohmic behavior at higher fields, but the barrier lowering is stronger than expected from this theory. While the leakage mechanism is comparable to SrTiO3 thin films prepared by chemical solution deposition, the absolute values of the leakage current are significantly lower for the metalorganic chemical vapor deposition (MOCVD) prepared BST film. This is presumably due to a more homogeneous microstructure of the latter and may also be due to different electrode processing. The influence of the film thickness on the leakage in combination with additional findings is used to discuss the field distribution in the films under a dc voltage stress. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Steroids which are synthesized within the nervous system, such as progesterone, have been termed ‘neurosteroids’. Levels of progesterone are much larger in peripheral nerves of rats and mice than in plasma, and persist after removal of the steroidogenic endocrine glands. Schwann cells are a source of progesterone: when isolated from embryonic dorsal root ganglia, they can synthesize progesterone from pregnenolone, the obligate precursor of all steroids. Locally produced progesterone has been shown to play an important role in myelination of peripheral nerve. We show here that sensory neurons from embryonic dorsal root ganglia also express 3β-hydroxysteroid dehydrogenase and can convert [3H]pregnenolone to [3H]progesterone. Moreover, when cultured under different conditions and incubated for 24 h in the presence of 100 nM [3H]pregnenolone, they produce 5–10 times more [3H]progesterone than Schwann cells. The conversion of pregnenolone to progesterone by neurons is further increased by a diffusible factor produced by Schwann cells. Sensory neurons can also metabolize progesterone to 5α-dihydroprogesterone, but unlike Schwann cells, they do not produce 3α,5α-tetrahydroprogesterone, a potent positive allosteric modulator of γ-aminobutyric acid type A receptors. We also show that cells isolated from the adult nervous system still have the capacity to convert [3H]pregnenolone to progesterone and its 5α-reduced metabolites: neurons and Schwann cells purified from dorsal root ganglia of 6 week old male rats show a similar pattern of pregnenolone metabolism to cells isolated from 18 day old embryos. These findings further support the important role of progesterone in the development and regeneration of the peripheral nervous system.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 1 (1998), S. 193-200 
    ISSN: 1434-601X
    Keywords: PACS:13.60.Fz Elastic and Compton scattering – 25.20.-x Photonuclear reactions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract: The present experimental state of the neutron polarizabilities is discussed. Two possibilities to extract the neutron polarizabilities from experiments are considered: i) quasi-free Compton scattering from the bound neutron and ii) scattering of slow neutrons in the Coulomb field of heavy nuclei. The latter experiments have led to an intense discussion from which we conclude that all attempts to measure the neutron polarizabilities using this method have failed. It is shown that quasi-free Compton scattering from the neutron bound in the deuteron at photon energies from 200 MeV to 300 MeV is the most promising method of measuring the neutron polarizabilities. To arrive at an experimental accuracy of ± 2· 10−4fm3 when extracting the electric polarizability ¯α n , one has to measure the differential cross section in the energy range from 200 MeV to 300 MeV at backward photon scattering angles with a precision of 5%. It is shown that theoretical uncertainties of the method are mainly due to the dependence of the cross section on the selection of multipole analysis of single pion photoproduction. At present they prevent the extraction of ¯α n with an accuracy better than ± 2· 10−4fm3.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 191 (1966), S. 343-353 
    ISSN: 1434-601X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Theγ-spectrum of Pt191 has been measured with a Ge(Li)-counter. In addition to earlier measurements about 20 newγ-rays have been found, 10 of them were known as conversion-lines in earlier investigations. The intensities of these conversion-lines and the estimatedγ-ray-intensities allowed the determination of conversion-coefficients. A new level-scheme with 5 new levels at 569, 602, 660, 865 and 940 keV is proposed.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 192 (1966), S. 305-312 
    ISSN: 1434-601X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Theγ-ray-spectrum of Fe56 associated with the E.C.- andβ +-decay of Co56 has been measured with Ge(Li)-crystals. 6 newγ-ray-transitions have been found in this spectrum deexciting 3 new levels in Fe56. The intensities of these transitions have been estimated and a new level-scheme is proposed. The new levels could be identified with some of previously reported levels found in Fe56(p, p′)-measurements.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 196 (1966), S. 298-310 
    ISSN: 1434-601X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Theγ-ray-spectrum of Ni60 associated with the E.C.- and β+-decay of Cu60 has been measured with Ge(Li)-crystals. The observedγ-ray-transitions led to a new levelscheme for this decay with Ni60-levels at: 1332, 2159, 2286, 2627, 3125, 3196, 3272, 3391, 4025, 4080, 4332, 4500, 4554 and 4584 keV, most of them could be identified with previously reported levels found in scattering experiments. As far as possible spin and parity assignments have been made, and the levels are compared with phonon and quasi-particle theory.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1433-0407
    Keywords: Schlüsselwörter Aciclovir ; Zentralnervöse Nebenwirkungen ; Psychosyndrom ; Key words Acyclovir ; Adverse effects ; Psychosyndrome
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary In differential diagnosis of a delir also adverse effects of medicaments have to be taken into account beside other causes. We report a case of an agitated delir with nocturnal disturbance of consciousness, confusion, restlessness and sleeplessness. This delir existed exclusively during the therapy of a cutaneous herpes zoster with zovirax®-pills which can only be explained by a causal connection – after exclusion of other causes. As a so far undescribed predisposition for neurotoxicity of oral therapy with acyclovir signs of vascular encephalopathy were found in the patient’s cranial magnetic resonance imaging. The central nervous side effects of acyclovir were summarized shortly.
    Notes: Zusammenfassung Bei der Differentialdiagnose eines Delirs müssen u. a. auch Medikamentennebenwirkungen bedacht werden. Vorgestellt wird ein Patient mit einem agitierten Delir in Form von nächtlicher Bewußtseinstrübung, Verwirrtheit, psychomotorischer Unruhe und Schlaflosigkeit. Dieses Delir bestand ausschließlich während der Therapie eines kutanen Herpes zoster mit Zovirax®-Tabletten, was – nach Ausschluß anderer Ursachen – nur durch einen kausalen Zusammenhang erklärt werden kann. Als eine bislang unbeschriebene Prädisposition für Neurotoxizität bei einer oralen Aciclovir-Therapie fanden sich im Kernspintomogramm des Patienten Zeichen einer vaskulären Enzephalopathie. Die zentralnervösen Nebenwirkungen von Aciclovir werden kurz zusammengefaßt.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    HNO 47 (1999), S. 816-820 
    ISSN: 1433-0458
    Keywords: Schlüsselwörter Glomus jugulare ; Bilateral ; Embolisation ; Key words Bilateral glomus jugulare tumors ; Paragangliomas ; Tumor embolization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Bilateral glomus jugulare tumors are rare. However, their treatment should preserve not only the function of the facial nerve but also the caudal cranial nerves and the middle ears in order to avoid bilateral hearing losses. Further, venous cerebral drainage has to be ensured in order to avoid cerebral hypertension and hemorrhagic infarction after bilateral jugular ligations. In the case presented bilateral glomus jugulare tumors required super-selective angiography and embolization. Complete tumor removal on both sides was then possible by a transmastoid-transcervical approach without any further functional deteriorations. Middle ear function was preserved on both sides by temporary ventral translocation of the posterior wall of the auditory meatus. As the sigmoid sinus and internal jugular vein had been ligated during initial previous surgery, venous drainage was tested one year later by angiography and compression of the remaining internal jugular vein. A sufficient collateral circulation was found and permitted surgery on the second side.
    Notes: Zusammenfassung Beidseitige Glomus-jugulare-Tumoren stellen eine Rarität dar. Neben der Funktion des N. facialis muß bei ihrer Entfernung auch die Funktion der kaudalen Hirnnerven berücksichtigt werden. Die Funktionserhaltung des Mittelohrs ist ebenfalls anzustreben, um einen beidseitigen Schalleitungsblock zu vermeiden. Die venöse zerebrale Drainage muß gesichert werden, da eine beidseitige Ligatur des Sinus sigmoideus zur zerebralen venösen Hypertension führen würde. Am Beispiel eines großen bilateralen Glomus-jugulare-Tumors der Klasse C2 ermöglichte die superselektive Angiographie und Embolisation die beidseitige vollständige Tumorentfernung ohne Funktionseinschränkungen über einen transmastoidalen-transzervikalen Zugang. Durch temporäre Ventralverlagerung der hinteren Gehörgangswand gelang auch die Erhaltung der Mittelohrfunktion. Wegen der Ligatur der V. jugularis interna und des Sinus sigmoideus auf der 1. Seite konnte die 2. Seite erst 1 Jahr später operiert werden, nachdem die Angiographie und Kompression der verbliebenen V. jugularis interna ausreichende venöse Kollateralen bestätigt hatte.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1432-055X
    Keywords: Schlüsselwörter Nosokomiale Infektionen ; Intensivstationen ; NIDEP ; Bundesweite Prävalenzstudie ; Key words Nosocomial infections ; Intensive care unit ; NIDEP ; Nationwide prevalence survey
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Abstract In a large, multicenter survey in 1994, the prevalence of nosocomial infections in German hospitals was examined, predominant pathogens were identified, and possible risk factors evaluated. In this paper the results from the intensive care units (ICUs) are presented. Methods. Seventy-two representative hospitals in Germany were selected by randomisation and divided into four different groups according to their size (〈200 beds; 200–400 beds; 400–600 beds; 〉600 beds). During 10 months four especially trained doctors documented the patients clinical and laboratory data and possible endogenous and exogenous risk factors for nosocomial infections. For better evaluation, they discussed the cases with the responsible senior officers and health care workers and visited the patients. Diagnosis of nosocomial infection was based on CDC criteria. Results. In 515 patients in 89 ICUs, 78 hospital-acquired infections were documented (15.3%). The most common were pneumonia (5.9%), bronchitis (2.7%), urinary tract infections (2.4%), and septicaemia (2.2%). Possible exogenous risk factors included: peripheral venous catheters (65.6%); catheterisation of the urinary tract (64.5%); central venous catheters (60.4%); gastric tubes (38.0%); wound drainage (28.6%) and artificial ventilation (27.6%). The most frequent concomitant diseases were cardiovascular (61.9%), diabetes (20.2%), malignancies (18.8%), pre-existing infections (15.3%), and chronic respiratory disease (14.0%). The prevalence of nosocomial infections was higher in hospitals with more than 600 beds than in smaller ones (28.3% versus 12.9%, P〈0.001). Predominant pathogens were Pseudomonas aeruginosa, enterococci, Staphylococcus aureus, Candida spp., Escherichia coli, and Klebsiella spp.. Fifty per cent of the ICUs changed ventilation tubes and 66.3% changed infusion sets daily; 34.8% of patients received drugs for the prevention of stress ulcers that neutralise or decrease production of gastric acid; only 7.6% received sucralfate. Routine microbiological surveillance of tracheal aspirates and urine was done by 25.9% and 24.6% of the ICUs, respectively. Discussion. Nosocomial infections are seen far more often in ICUs than on normal wards due to the immunosuppressed state of many ICU patients and the continuous use of invasive diagnostic and therapeutic procedures. Most of these infections are of endogenous origin. Other prevalence surveys have shown results comparable to ours. Daily changing of ventilation tubes is no longer necessary, but is still routine in many hospitals. Infusion sets were also changed more often than required. The use of selective decontamination of the digestive tract for the prevention of pneumonia is still controversial; in our study it was practised in only 1.5% of the cases. The most commonly used drugs for the prevention of stress ulcers were H2-receptor blocking agents, although it has been shown that sucralfate is the better choice, as it can help prevent nosocomial pneumonia. Routine microbiological surveillance of tracheal aspirates and urine was done in 25.9% and 24.6% of the ICUs. No study so far has shown that routine cultures of tracheal secretions and urine have a preventive effect regarding infection.
    Notes: Zusammenfassung Im Auftrag des Bundesgesundheitsministeriums wurde von Januar bis Oktober 1994 eine für Deutschland repräsentative Prävalenzstudie mit insgesamt 14966 Patienten an 72 nach Größenklassen ausgewählten Kliniken mit dem Ziel durchgeführt, nosokomiale Infektionen, potentielle Risikofaktoren und Hygienemaßnahmen zu erfassen (NIDEP: Nosokomiale Infektionen in Deutschland – Erfassung und Prävention). Auf 89 Intensivstationen hatten von 515 Patienten 78 (15,3%) mindestens eine nosokomiale Infektion. Die häufigsten Infektionen waren Pneumonie (5,9%), Tracheobronchitis (2,7%), Harnwegsinfektion (2,4%) und primäre Sepsis (2,2%). Die häufigsten potentiellen endogenen Risikofaktoren für Krankenhausinfektionen waren Herz-Kreislauferkrankungen (61,9%), Diabetes mellitus (20,2%), Malignome (18,8%), vorbestehende Infektionen (15,3%) und chronische Atemwegserkrankungen (14,0%). Für die potentiell exogenen Risikofaktoren ergaben sich folgende Prävalenzen: Periphere Venenkatheter (65,6%), Harndrainagen (64,5%), zentrale Venenkatheter (60,4%), Magensonden (38,0%), Wunddrainagen (28,6%), und kontrollierte Beatmung (27,6%). 50,0% der Intensivstationen wechselten die Beatmungsschläuche und 66,3% die Infusionssysteme immer noch täglich. Bei 34,8% der Patienten wurde eine säurehemmende Streßulkusprophylaxe durchgeführt, lediglich 17,6% der Patienten erhielten Sucralfat. Die Mehrzahl der Intensivstationen führte kein routinemäßiges mikrobiologisches Monitoring durch. Einige Intensivstationen untersuchten jedoch Urin und Trachealsekret täglich. Die häufigsten Erreger nosokomialer Infektionen auf Intensivstationen waren in absteigender Reihenfolge Pseudomonas aeruginosa, Enterokokken, Staphylococcus aureus, Candida spp., Escherichia coli, Klebsiella spp.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Intensive care medicine 22 (1996), S. 1155-1161 
    ISSN: 1432-1238
    Keywords: Nosocomial pneumonia ; scoring system ; Risk factors ; Intensive care units
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Objective To develop a scoring system for stratifying patients in intensive care units (ICUs) by risk of developing nosocomial pneumonia (NP), based on variables generally available in an ICU, and to determine the probability of a patient developing NP in the ICU. Design and setting A 2-year prospective cohort study conducted in a medical and surgical ICU. Patients 756 patients admitted to the ICU for 48 h or more were followed up until the development of NP or death or discharge from the ICU. Measurements and results 129 (17.1%) patients developed NP, 106 (14%) in the first 2 weeks. The following independent risk factors were identified by multivariate analysis: no infection on admission [relative risk (RR)=3.1, 95% confidence intervals (CI)=2.0 to 4.8]; thorax drainage (RR=2.1, 95% CI=1.2 to 3.5); administration of antacids (RR=2.1, 95% CI=1.4 to 3.1); partial pressure of oxygen (PO2)〉110 mmHg (RR=1.6, 95% CI=1.0 to 2.6); administration of coagulation factors (RR=1.8, 95% CI=1.0 to 3.2); male gender (RR=2.7, 95% CI=1.2 to 6.3); urgent surgery (RR=2.4, 95% CI=0.9 to 6.4); and neurological diseases (RR=4.2, 95% CI=1.9 to 9.4). To obtain a predictive risk index for NP, a scoring system was developed using a multivariate model. The probability of developing NP varied between 11.0% in the lowest risk group and 42.3% in the highest risk group. The patients' risk of acquiring NP was seven times higher in the highest score category (IV) than in the lowest one (I). Conclusions ICU patients can be stratified into high- and low-risk groups for NP. No infection on admission, thorax drainage, administration of antacids, and PO2〉110 mmHg were associated with a higher risk of NP during the entire 2-week period.
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