Some low-leakage properties of silicon junction field-effect transistors

Factors governing the direct gate current in silicon field-effect transistors are reviewed, and a mode of operation which results in zero d.c. gate leakage is described. This leads to the postulation of a new d.c. equivalent circuit for the field-effect-transistor gate.     

Differential minority-carrier-storage circuit for fast-pulse generation

A balanced system of minority-carrier-storage diodes, energised from avalanche-pulse generators, is described, which delivers fast-rise/fast-fall pulses of adjustable length. Nanosecond risetime is obtained with step-recovery diodes; readily available charge-storage coupling diodes may be used to achieve 5 ns rise and fall times and amplitudes of some tens of volts into 50 ?.     

Using aqueous chlorine dioxide to prevent contamination of tomatoes with Salmonella enterica and erwinia carotovora during fruit washing

Chlorine dioxide (ClO2) is an antimicrobial agent recognized for its disinfectant properties. In this study, the sanitizing effects of ClO2 solutions against Salmonella enterica and Erwinia carotovora in water, on tomato surfaces, and between loads of tomatoes were evaluated. In water, ClO2 at 5, 10, and 20 ppm caused a > or = 5-log reduction of S. enterica within 6, 4, and 2 s, respectively. Higher lethality was observed with E. carotovora; a 5-log reduction was achieved after only 2 s with 10 ppm ClO2. On fruit surfaces, however, the sanitizing effects were compromised. A full minute of contact with ClO2 at 20 and 10 ppm was required to achieve a 5-log reduction in S. enterica and E. carotovora counts, respectively, on freshly spot-inoculated tomatoes. On inoculated fruit surfaces, populations decreased > 3 log CFU/cm2 during desiccation at 24 +/- 1 degrees C for 24 h. Populations of air-dried Salmonella and Erwinia were not significantly reduced (P > 0.05) by ClO2 at < or = 20 ppm after 1 min. Either wet or dry inoculum of these two pathogens could contaminate immersion water, which in turn can cross-contaminate a subsequent load of clean fruit and water. ClO2 at 5 ppm used for immersion effectively prevented cross-contamination. Pathogen contamination during fruit handling is best prevented with an effective disinfectant. Once a load of fruit is contaminated with pathogens, even a proven disinfectant such as ClO2 cannot completely eliminate such contaminants, particularly when they are in a dehydrated state on fruit.     

Disrupted splenic architecture, but normal lymph node development in mice expressing a soluble lymphotoxin-beta receptor-IgG1 fusion protein

Early in ontogeny, the secondary lymphoid organs become populated with numerous cells of mesodermal origin which forms both the lymphoid and stromal elements. The critical receptor/ligand interactions necessary for lymphoid organogenesis to occur are for the most part unknown. Although lymphotoxin-alpha (LT alpha) has been shown to be required for normal lymph node, Peyer's patch, and splenic development, it is unclear if soluble LT alpha 3, and/or cell-bound lymphotoxin-alpha beta (LT alpha beta) mediate these developmental events. Here we report that blocking LT alpha beta/lymphotoxin-beta receptor (LT beta R) interaction in vivo by generating mice which express a soluble LT beta R-Fc fusion protein driven by the human cytomegalovirus promoter results in an array of anatomic abnormalities affecting both the spleen and Peyer's patches, but not the lymph nodes. These results demonstrate that surface LT alpha beta ligand plays a critical role in normal lymphoid organ development.     

Phase I and pharmacologic study of paclitaxel and cisplatin with granulocyte colony-stimulating factor: neuromuscular toxicity is dose-limiting

PURPOSE: To determine the maximum-tolerated doses (MTD), the principal toxicities, and the pharmacologic behavior of high doses of Taxol (paclitaxel; Bristol-Myers Squibb, New York, NY) combined with cisplatin and granulocyte colony-stimulating factor (G-CSF). PATIENTS AND METHODS: Untreated and minimally pretreated solid-tumor patients received 24-hour infusions of Taxol on day 1 followed by cisplatin on day 2 and G-CSF, 5 micrograms/kg/d subcutaneously (SC), beginning on day 3. Treatment was repeated every 3 weeks. Starting doses of Taxol and cisplatin were 135 and 75 mg/m2, respectively. RESULTS: The development of a severe peripheral neuropathy and/or severe myalgias precluded the chronic administration of Taxol and cisplatin with G-CSF at doses greater than 250 mg/m2 and 75 mg/m2, respectively. At this dose, the mean Taxol steady-state plasma concentration (Css) exceeds concentrations capable of inducing pertinent antimicrotubule effects in vitro. The severity of the neuropathy was related to the cumulative dose of Taxol, the magnitude of the dose administered during each treatment, and the presence of a pre-existing medical disorder associated with peripheral neuropathy. A proximal myopathy of modest severity also was documented. Although severe neutropenia occurred frequently, especially at the MTD, it was rarely associated with fever (8% of courses), and absolute neutrophil counts (ANCs) less than 500/microL never persisted for more than 5 days. Responses were noted in non-small-cell lung cancer (NSCLC) and head and neck, breast, and esophageal cancers. CONCLUSION: Taxol and cisplatin doses of 250 mg/m2 and 75 mg/m2, respectively, can be administered repetitively with G-CSF to untreated and minimally pretreated patients. However, these doses are not recommended for patients with pre-existing neuropathies until additional experience in high-risk patients is obtained. Although this Taxol dose is nearly 85% higher than the dose that can be combined with cisplatin in the absence of G-CSF, this high-dose regimen should not be used outside the investigational setting until a dose-response relationship has been demonstrated for Taxol in randomized clinical trials.     

In vivo quantitation of epithelial lining fluid in dog lung

We used an original saturation bronchoalveolar lavage (SBAL) technique (Eur. Respir. J. 1995;8[Suppl. 19]398S) to quantitate lung epithelial lining fluid volume (VELF) in dogs in two separate experiments: control and after oleic-acid-induced injury. We confirmed the hypothesis that 99mTc-DTPA, infused at constant plasma activity, reaches equilibrium with epithelial lining fluid after 90 min. We performed eight sequential lavages 215 min after beginning the infusion of 99mTc-DTPA. 99mTc-DTPA activity (Qn) in the lavage fluid increased linearly with time, suggesting transport from the plasma into the alveoli during lavage. We extrapolated Qn to time zero (Q0), when 99mTc-DTPA was not affected by lavage. VELF was calculated from: VELF = Q0/Cp, (Cp: 99mTc-DTPA mean plasma activity). 125I-albumin was used as a nondiffusible alveolar indicator to measure the fluid volume present in the lavaged segment (Vt,n). Vt,n plateaud for n >= 4. VELF/Vt,n(n = 5,8) was 1.7 +/- 0.4 and 25.0 +/- 4.4% (p < 0.05) in control and injury experiments, respectively. SBAL allowed reliable measurements of VELF and detection of alveolar edema fluid in the injured lung.     

Women and menopause: beliefs, attitudes, and behaviors. The North American Menopause Society 1997 Menopause Survey

It has been demonstrated that exposure to mercury or cadmium compounds causes alterations in the glutathione system in a model glial cell line, C6. Here we report that two organic tin compounds, triethyltin (TET) and trimethyltin (TMT), are also toxic to these cells with EC50 values for cell death of c. 0.02 microM and 0.8 microM respectively. Exposure for 24 h to either of these compounds at sub-toxic concentrations caused increases in the amount of reduced glutathione (GSH) per cell. Increases in glutathione-S-transferase enzyme activity were also demonstrated after TET or TMT exposure. This suggests that glutathione increases occur in glial cells after toxic insults below that required to cause cell death, possibly acting as a protective mechanism. To test whether GSH plays a role in organotin-induced cell death we manipulated GSH in the culture media or via intracellular GSH and looked at the effects on sensitivity to TET or TMT toxicity. Adding GSH to the culture media did not protect the cells. Depletion of intracellular GSH with buthionine-[S,R] sulphoximine did not alter cytotoxicity of TET or TMT. However, pre-treatment with (-)-2-oxo-4-thiazolidine carboxylic acid (OTC), which increases intracellular GSH levels, protected the cells against both compounds. The EC50 for TMT was increased from 0.77 to 1.8 microM, a 2.3-fold shift, whereas the EC50 for TET was increased > 20-fold, from 0.022 to 0.47 microM. One interpretation of these results is that GSH protects cells against the toxicity of organic tin compounds without reacting directly with them to any significant extent. Under conditions where GSH is depleted, additional protective mechanisms may be active.     

Effect of subdiaphragmatic vagotomy on the pH profile of the wall of the gastrointestinal'' tract of rats with chronic experimental duodenal ulcers

During 1979, three brothers had antibody titers for toxoplasmosis of 1:1,024, 1:64, and 1:16, respectively, by IgG indirect immunofluorescent antibody (IgG-IFA) test. The first child also had a fever and lymphadenopathy. In August 1980 the three children had lymphadenopathy and IgG-IFA test titers between 1:4,096 and 1:16,000. Two other brothers, first examined at that time, had IgG-IFA test titers between 1:1,024 and 1:4,096, one with ascending titers and the other with IgM antibodies to Toxoplasma gondii. The latter had lymphadenopathy, fever, and hepatosplenomegaly. Clinical and serologic examinations during March, April, and September 1981 revealed good health and decreasing IgG-IFA test titers in most of the brothers. The simultaneous increase of antibody titers during August 1980 in the three initial patients lead to the consideration of a probable reinfection. A simultaneous reactivation of the disease was considered less probable because acute toxoplasmosis occurred in two other brothers at the same time.     

Noncontact test signal acquisition

An arrangement of electrostatic pickups for logic signals is described; this allows data over a wide range of repetition rates to be acquired from insulated wires or from insulation-covered printed circuits. Minimum coupling capacities are of the order of 1 pF and it is shown that 5 V pulses from 0.5 Hz to 5 MHz can be detected and reproduced. Preliminary results are also reported for an electrostatic pickup system for audio frequency analogue signals. Applications are suggested in high voltage DC isolation of analogue or digital circuits, noncontact computer bus couplers and diagnostic probes.     

Operant regulation of feeding: A static analysis.

Conducted 3 experiments using cyclic-ratio schedules, a rapid method for studying the operant regulation of feeding rate. The cyclic method produces results comparable to traditional but time-consuming parametric methods. Ss in Exp I were 8 female albino rats, 4 of which were also used in Exps II and III. Performance on cyclic-ratio schedules is well described by a linear regulatory model that embodies 3 quantitative feedback assumptions: (a) that rate of feeding is regulated by the rate of operant behavior, (b) that taste factors have an additive effect on the rate of the operant response, and (c) that regulatory "gain" is inversely related to body weight. This model accurately describes poorer regulatory performance at high body weights and following amphetamine administration, and the effects of altered diet palatability on preferred feeding rates. (28 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)