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  • 1
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 64 (1994), S. 2022-2024 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have developed a quasicontinuous crucible free zone melting method for texturing YBCO bulk material. Dense sintered rods with a length of 10 cm were partially molten in the hot zone of a 5 zone furnace and recrystallized in the large temperature gradient (140 °C/cm) limiting this zone. Suitable additions of Y2BaCuO5 (20 mol %) and PtO2 (1 wt %) to the starting material and a growth rate of not more than 1 mm/h were necessary to obtain stable growth conditions. After natural grain selection we obtained 8-cm-long rods with a uniform orientation of the crystallographic axes within 2°. The angle between c direction and rod axis typically was 55°. The critical current density at 77 K measured with continuous current over a length of 4.5 cm was 1.3×104 A/cm2 in zero field and 8×103 A/cm2 in 0.5 T. These values confirm the absence of grain boundaries.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Monatsschrift Kinderheilkunde 147 (1999), S. 754-755 
    ISSN: 1433-0474
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-041X
    Keywords: Key words Pigment pattern ; Fin ; Fish skeleton ; Tyrosinase ; Zebrafish
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Mutations causing a visible phenotype in the adult serve as valuable visible genetic markers in multicellular genetic model organisms such as Drosophila melanogaster, Caenorhabditis elegans and Arabidopsis thaliana. In a large scale screen for mutations affecting early development of the zebrafish, we identified a number of mutations that are homozygous viable or semiviable. Here we describe viable mutations which produce visible phenotypes in the adult fish. These predominantly affect the fins and pigmentation, but also the eyes and body length of the adult. A number of dominant mutations caused visible phenotypes in the adult fish. Mutations in three genes, long fin, another long fin and wanda affected fin formation in the adult. Four mutations were found to cause a dominant reduction of the overall body length in the adult. The adult pigment pattern was found to be changed by dominant mutations in wanda, asterix, obelix, leopard, salz and pfeffer. Among the recessive mutations producing visible phenotypes in the homozygous adult, a group of mutations that failed to produce melanin was assayed for tyrosinase activity. Mutations in sandy produced embryos that failed to express tyrosinase activity. These are potentially useful for using tyrosinase as a marker for the generation of transgenic lines of zebrafish.
    Type of Medium: Electronic Resource
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  • 5
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    London : Periodicals Archive Online (PAO)
    Journal of historical geography. 17:1 (1991:Jan.) 1 
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  • 6
    ISSN: 1432-1076
    Keywords: Surfactant ; Idiopathic respiratory distress syndrome ; Clinical trial ; Randomization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We performed a multicenter prospective randomized controlled trial to determine the efficacy and safety of the surfactant preparation, Survanta (Abbott Laboratories, Chicago, USA), for 750–1750 g infants with idiopathic respiratory distress syndrome, (IRDS) receiving assisted ventilation with 40% or more oxygen. One hundred and six eligible infants from the eight participating centers were randomly assigned between March 1986 and June 1987 to receive either surfactant (100 mg phospholipid/kg, 4 ml/kg) or air (4 ml/kg) administered into the trachea within 8 h of brith (median time of treatment 6.2 h, range 3.2–9.1 h). The study was stopped before enrollment was completed at the request of the United States Food and Drug Administration when significant differences were observed in incidence of periventricular-intraventricular hemorrhage (PIH), between the surfactant treated and control infants. Surfactant treated infants had larger average increases in the arterial-alveolar oxygen ratio, (a/A ratio) (P〈0.0001), and larger average decreases in FiO2 (P〈0.0001) and mean airway pressure, (MAP) (P〈0.017) than controls over the 48 h following treatment. The magnitude of the differences between the surfactant and control groups were 0.19 (SE=0.03) for a/A ratio, −0.28 (SE=0.04) for FiO2 and −1.7 cm H2O (SE=0.70) for MAP. The clinical status on days 7 and 28 after treatment was classified using four predefined ordered categories: (1) no respiratory support; (2) supplemental O2 with or without continuous positive airway pressure (CPAP); (3) intermittent mandatory ventilation; and (4) death. There were no statistically significant differences in the status categories on days 7 or 28 between surfactant and control infants. There were no significant differences between the groups with respect to the incidence of patent ductus arteriosus, bronchopulmonary dysplasia, necrotizing entero-colitis, air leaks or death. There was a statistically significant difference between treated and control infants in the frequency and severity of periventricular-intraventricular hemorrhage (PIH) (Cochran-Mantel-Haenszelχ 2adj=6.36,P=0.01). Hemorrhages occurred in 59.6% of surfactant treated infants and 26.9% of controls. Severe hemorrhages (grades 3 or 4) occurred in 38.5% of surfactant treated infants and 15.4% of controls (χ 2adj=4.01,P=0.045). We conclude that the intratracheal administration of Survanta prior to 8 h of age to infants with IRDS receiving assisted ventilation with 40% or more oxygen results in a reduction in the severity of respiratory distress during the 48 h after therapy. Because of the difference in incidence of PIH between surfactant and control infants in this study, we recommend that future clinical trials of surfactant include more frequent prospective serial ultrasound evaluations for diagnosis of hemorrhage.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-8798
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Lytic transition of Epstein-Barr virus (EBV) is initiated by distinct immediate early regulators of the viral cycle, in synchronization to temporary, permissive conditions during host cell differentiation. We developed eukaryotic vectors suitable to imitate the processes involved in lytic transition in cell culture systems. Two stable B cell lines were established: R59Z activator cells were used to induce lytic EBV expression in a constitutive manner by the production of the BZLF 1trans-activator (Zta). R7-57 reporter cells, on the other hand, signaled induced activity of the lytic origin of EBV replication (oriLyt). Different modes, like chemical induction, lytic superinfection with EBV and single genetrans-activation converted the recombinant oriLyt element in R7-57 reporter cells. BZLF 1, transiently expressed in R7-57 reporter cells, was the only EBVtrans-activator found, sufficient in inducing the viral lytic cycle. Basing on these experiments,trans-cellular activation of EBV was tested by cocultivation of BZLF 1-expressing R59Z activator cells with the R7-57 reporter line. No lytic effect on the reporter cells could be measured, neither by cocultivation of activator cells nor by coincubation of BZLF 1-containing cell lysates. Latency breaking activity, however, was transferred from activator to reporter cells when active, exogenous virus was added. The cell system described in these experiments provides a tool for the detection of EBV reactivation and demonstrates the potential of the lytic regulatory gene BZLF 1.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1573-0743
    Keywords: aortic valvuloplasty ; aortic stenosis ; balloon catheters ; computed axial tomography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In order to evaluate the relation between balloon design (monofoil, trefoil) and valvular configuration, experimental aortic valvuloplasty was performed in four post-mortem hearts with calcific aortic stenosis of various morphology. The degree of obstruction of the aortic orifice was assessed by computed axial tomography during inflation of monofoil 15 and 19 mm and trefoil 3×12 mm balloon catheters. We also evaluated the hemodynamic repercussion of balloon inflation (fall in systolic aortic pressure) in four elderly patients with acquired aortic stenosis who underwent a percutaneous transluminal aortic balloon valvuloplasty, with stepwise increasing balloon sizes of 15 mm, 19 mm and 3×12 mm, as during ourin vitro experiments, and who underwent aortic valve replacement later on. In these patients, we correlated the anatomy of the excised aortic valves with the retrospective analysis of aortic pressure curves recorded during previous valvuloplasty procedures. Our experimental and clinicopathological observations showed that the degree of obstruction of the aortic orifice in post-mortem specimens and the tolerance to balloon inflation in live patients are dependent of the valvular configuration. Although trefoil balloons have the theoretical advantage to avoid complete obstruction of the aortic orifice during inflation, we observed that in presence of a tricuspid configuration, they could be potentially more occlusive than monofoil balloons since each of the 3 individual components of the trefoil balloon occupied the intercommissural spaces while inflated. However, they offered more residual free space when inflated in aortic valves with a bicuspid configuration (i.e. congenitally bicuspid valves or tricuspid valves with one fused commissure). In our opinion, these observations are relevant, since degenerative disease of the aortic valve (i.e. tricuspid valve without commissural fusion) is now recognized as the most common etiology of aortic stenosis in the elderly.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Journal of inherited metabolic disease 22 (1999), S. 221-223 
    ISSN: 1573-2665
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Journal of inherited metabolic disease 18 (1995), S. 33-39 
    ISSN: 1573-2665
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Tetrahydrobiopterin (BH4) is the cofactor for the aromatic amino acid monoxygenase group of enzymes and for all known isoforms of nitric oxide synthase (NOS). Inborn errors of BH4 metabolism lead to hyperphenylalaninaemia and impaired catecholamine and serotonin turnover. The effects of BH4 deficiency on brain nitric oxide (NO) metabolism are not known. In this study we have used thehph-1 mouse, which displays GTP cyclohydrolase deficiency, to study the effects of BH4 deficiency on brain NOS. In the presence of exogenous BH4, NOS specific activity was virtually identical in the control andhph-1 preparations. However, omission of BH4 from the reaction buffer led to a significant 20% loss of activity in thehph-1 preparations only. TheK m for arginine was virtually identical for the control andhph-1 NOS when BH4 was present in the reaction buffer. In the absence of cofactor, theK m for arginine was 3-fold greater for control and 5-fold greater forhph-1 preparations. It is concluded that (a) BH4 does not regulate the intracellular concentration of brain NOS; (b) less binding of BH4 to NOS occurs in BH4 deficiency states; (c) BH4 has a potent effect on the affinity of NOS for arginine; and (d) the availability of arginine for NOS activity may become severely limiting in BH4 deficiency states. Since, in the presence of suboptimal concentrations of BH4 or arginine, NOS may additionally form oxygen free-radicals, it is postulated that in severe BH4 deficiency states NO formation is impaired and the central nervous system is subjected to increased oxidative stress.
    Type of Medium: Electronic Resource
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