Effect of a temperature gradient on bubble growth in tungsten

Bubble distributions in doped tungsten wires have been examined following high temperature anneals (2500° to 3000°C) both in the presence and absence of a thermal gradient. Electron and optical microscopy show that much more bubble growth occurs during gradient anneals, and the results suggest that the gradient is a driving force for bubble growth. This process takes place predominantly on the grain boundaries. Semiquantitative estimates of the bubble flux were made by measuring the change in aggregate bubble surface areas found at various positions in the gradient. Stress induced bubble growth was shown not to be a factor.     

Effect of growth temperature and culture age on the lipid composition of Vibrio cholerae 569B (Inaba)

The relative amounts of the major phospholipids (phosphatidylethanolamine, phosphatidylglycerol and lyso-phosphatidylethanolamine) and fatty acids in Vibrio cholerae 569B (Inaba) varied with growth temperature and between exponential and stationary phases of growth.     

Effect of growth temperature on the cryopreservation of prototheca

The temperature at which Prototheca spp. were grown determined their response to freezing to -196 degrees C and subsequent thawing. Cells cultured at 35 degrees C were the most sensitive to freezing injury; at lower growth temperatures, resistance to freezing damage was seen. At all culture temperatures examined, the freezing tolerance varied with the age of the culture.     

Effect of tocotrienols on the growth of a human breast cancer cell line in culture

The tocotrienol-rich fraction (TRF) of palm oil consists of tocotrienols and some alpha-tocopherol (alpha-T). Tocotrienols are a form of vitamin E having an unsaturated side-chain, rather than the saturated side-chain of the more common tocopherols. Because palm oil has been shown not to promote chemically-induced mammary carcinogenesis, we tested effects of TRF and alpha-T on the proliferation, growth, and plating efficiency (PE) of the MDA-MB-435 estrogen-receptor-negative human breast cancer cells. TRF inhibited the proliferation of these cells with a concentration required to inhibit cell proliferation by 50% of 180 microgram/mL whereas alpha-T had no effect at concentrations up to 1000 microgram/mL as measured by incorporation of [3H]thymidine. The effects of TRF and alpha-T also were tested in longer-term growth experiments, using concentrations of 180 and 500 microgram/mL. We found that TRF inhibited the growth of these cells by 50%, whereas alpha-T did not. Their effect on the ability of these cells to form colonies also was studied, and it was found that TRF inhibited PE, whereas alpha T had no effect. These results suggest that the inhibition is due to the presence of tocotrienols in TRF rather than alpha T.     

Effect of various hormonal preparations on trophoblast growth in tissue culture

The application of different methods of tissue culture, in particular, investigations on trophoblast cells outside the mother's body, opens new possibilities for understanding pathogenesis of premature interruption of pregnancy caused by the hormonal and metabolic disorders. To study the effects of various hormones (Choriogonien, estrone and estradiol) on the growth and development of trophoblast cells the method of tissue culture was applied. 683 histological preparations, obtained after incubating trophoblast tissues with and without hormones were examined. It was established that choriogonine in doses of 5-100 IU/L stimulated growth in trophoblast cells but 200-400 IU/L of hormone did not increase this stimulating effect. Estrone and estradiol added to incubated tissues in doses of 60-120 IU/L brought about no changes or else had a weak effect on development of cultivated tissues. When choriogonine (or estrone) was added to the trophoblast tissues together with blood serum taken from women in danger of premature interruption of pregnancy the negative effect of the serum on the development of the trophoblast cells was prevented.     

Effect of lincomycin on a cell culture

Cumulative and toxic properties of lincomycin evident from increased numbers of pathological mitosis were found on three-fold treatment of various cell lines with the antibiotic in concentrations of 100 or 200 Units/ml for 1.5 years. The toxicity level was not high since the other indices of the mitotic regimen remained unchanged.     

Effect of matrix metalloproteinases activity on outflow in perfused human organ culture

PURPOSE: To test the hypothesis that extracellular matrix turnover, mediated by the matrix metalloproteinases, modulates aqueous humor outflow facility in a human outflow model. METHODS: Matrix metalloproteinase activity was manipulated and outflow facility evaluated using perfused human anterior segment organ culture. Purified matrix metalloproteinases, tissue inhibitors of metalloproteinases (TIMPs), and several families of synthetic inhibitors of matrix metalloproteinases were added to the perfusion medium. Matrix metalloproteinase expression was increased by adding recombinant interleukin (IL)-1alpha. Kinetic inhibition analysis was conducted for stromelysin, gelatinase A, and gelatinase B with the various inhibitors. Live-dead staining was used to evaluate culture viability. RESULTS: Increasing metalloproteinase activity, by adding purified metalloproteinases or by inducing their expression by IL-1alpha treatment, increased outflow facility. Inhibition of endogenous trabecular metalloproteinase activity using TIMP or several families of synthetic metalloproteinase inhibitors reduced outflow rates. The elevation and the reduction of outflow rates were reversible, with changes requiring 1 to 3 days. Kinetic enzyme inhibition analysis produced 50% inhibitory concentration values for these inhibitors that were compatible with the concentration ranges for outflow inhibition. CONCLUSIONS. The ability of several specific matrix metalloproteinase inhibitors to reduce outflow facility implies that endogenous extracellular matrix turnover by these enzymes was required for the maintenance of trabecular outflow resistance, at least in this human culture model. These observations provide support for the hypothesis that controlled extracellular matrix turnover is important in the regulation of aqueous humor outflow facility.     

Effect of timing of growth hormone administration on plasma growth-hormone-binding activity, insulin-like growth factor-I and growth in children with a subnormal spontaneous secretion of growth hormone

Since normal pulsatile growth-hormone (GH) secretion displays a major and consistent surge during sleep, we studied the effect of timing of GH supplementation on plasma GH-binding protein activity (GH-BP), insulin-like growth factor-I (IGF-I) and growth. 34 prepubertal subjects (28 boys, 6 girls) aged 8-11 years, of short stature (< 2 SD for age), with a GH response to provocative test > 10 micrograms/l and a subnormal 24-hour GH secretion (< 3 micrograms/l), were randomly allocated to receive Bio-Tropin (recombinant GH, Bio-Technology, Israel) 0.81 IU/kg/week in 3 equally divided doses. GH was administered either at 8.00-10.00 h (M group), 14.00-16.00 h (AN group) or 19.00-21.00 h (NT group). Height velocity, IGF-I and GH-BP were determined prior to and after 6 and 12 months on GH therapy in the three groups. There was no significant difference between the three groups in the growth response, IGF-I and GH-BP increase, all of which increased significantly during GH therapy. Although GH levels after the injection decline to preinjection levels after 10 h, the changes induced by GH therapy, as reflected in IGF-I and GH-BP, last in the circulation long enough to prevent fluctuations in its action. The similarity of IGF-I and of GH-BP levels in the three treatment groups might explain the similar growth effects of the 3 protocols.     

Development and evaluation of a predictive model for the effect of temperature and water activity on the growth rate of Vibrio parahaemolyticus

The growth rates of four strains of Vibrio parahaemolyticus were measured and compared in a model broth system. The results for the fastest growing strain, based on 77 combinations of temperature and water activity (aw) using NaCl as the humectant, were summarised in the form of a predictive mathematical model. The model, of the square-root type includes a novel term to describe the effects of super-optimal water activity, and can be used to predict generation times for the temperature range (8-45 degrees C) and water activity range (0.936-0.995) which permit growth of Vibrio parahaemolyticus. Predicted generation times from the model were compared to literature data, using bias and accuracy factors, for both laboratory media and foods. The model was shown to give realistic growth estimates, with a bias value of 1.01, and an accuracy factor of 1.38.     

Toxicity of N-substituted aromatics to acetoclastic methanogenic activity in granular sludge

N-substituted aromatics are important priority pollutants entering the environment primarily through anthropogenic activities associated with the industrial production of dyes, explosives, pesticides, and pharmaceuticals. Anaerobic treatment of wastewaters discharged by these industries could potentially be problematical as a result of the high toxicity of N-substituted aromatics. The objective of this study was to examine the structure-toxicity relationships of N-substituted aromatic compounds to acetoclastic methanogenic bacteria. The toxicity was assayed in serum flasks by measuring methane production in granular sludge. Unacclimated cultures were used to minimize the biotransformation of the toxic organic chemicals during the test. The nature and the degree of the aromatic substitution were observed to have a profound effect on the toxicity of the test compound. Nitroaromatic compounds were, on the average, over 500-fold more toxic than their corresponding aromatic amines. Considering the facile reduction of nitro groups by anaerobic microorganisms, a dramatic detoxification of nitroaromatics towards methanogens can be expected to occur during anaerobic wastewater treatment. While the toxicity exerted by the N-substituted aromatic compounds was closely correlated with compound apolarity (log P), it was observed that at any given log P, N-substituted phenols had a toxicity that was 2 orders of magnitude higher than that of chlorophenols and alkylphenols. This indicates that toxicity due to the chemical reactivity of nitroaromatics is much more important than partitioning effects in bacterial membranes.     

Cellular levels of factor 390 and methanogenic enzymes during growth of Methanobacterium thermoautotrophicum deltaH

Methanobacterium thermoautotrophicum deltaH was grown in a fed-batch fermentor and in a chemostat under a variety of 80% hydrogen-20% CO2 gassing regimes. During growth or after the establishment of steady-state conditions, the cells were analyzed for the content of adenylylated coenzyme F420 (factor F390-A) and other methanogenic cofactors. In addition, cells collected from the chemostat were measured for methyl coenzyme M reductase isoenzyme (MCR I and MCR II) content as well as for specific activities of coenzyme F420-dependent and H2-dependent methylenetetrahydromethanopterin dehydrogenase (F420-MDH and H2-MDH, respectively), total (viologen-reducing) and coenzyme F420-reducing hydrogenase (FRH), factor F390 synthetase, and factor F390 hydrolase. The experiments were performed to investigate how the intracellular F390 concentrations changed with the growth conditions used and how the variations were related to changes in levels of enzymes that are known to be differentially expressed. The levels of factor F390 varied in a way that is consistently understood from the biochemical mechanisms underlying its synthesis and degradation. Moreover, a remarkable correlation was observed between expression levels of MCR I and II, F420-MDH, and H2-MDH and the cellular contents of the factor. These results suggest that factor F390 is a reporter compound for hydrogen limitation and may act as a response regulator of methanogenic metabolism.     

Cu^2＋对氧化亚铁硫杆菌（T.f）生长活性的影响

了氧化亚铁硫杆菌（Ｔ．ｆ）在温度３０℃、ｐＨ２．０的常用浸出条件下,Ｃｕ＾２＿对抗一长活性的影响,试验结果表明,Ｃｕ＾２＋对氧化亚铁硫杆菌的生长活性有较大影响,表现在细菌生长的停带期和对数期均较长,Ｆｅ＾２＋的氧化速度较慢;经驯化后的细菌（Ｔ．ｆ）,在ｐ（Ｃｕ＾２＋）＝２０～３０ｇ／Ｌ的培养基中生长活性有提高,表现在对Ｆｅ＾２＋的氧化速率加快。     

Effect of dietary protein and environmental temperature on growth performance and water consumption of male broiler chickens

The purpose of this study was to investigate whether smokers outside buildings with work-place smoking bans smoke "harder" than those smoking in social settings. An unobtrusive random observational study of smokers followed by structured interview was used, with 143 smokers taking smoking breaks outside their office buildings and 113 smokers in social settings. The main outcome measurements were number of puffs per cigarette and cigarette smoking duration. The mean number of puffs per cigarette for the office building group was 18.7% greater than that for the social settings group (10.7 +/- 3.2 vs. 8.7 +/- 2.7, t = 5.58, df = 253, p < 0.001); 74.8% of smokers outside offices took more than the mean number of puffs for the group compared to 42.5% of smokers in social settings (chi 2 df 1 = 26.31, p < 0.0001). Mean cigarette smoking duration was 30.4% shorter for the work-place group than the social settings group (3.9 +/- 1.2 minutes vs. 5.6 +/- 2.6 minutes). Of smokers outside offices, 55.2% had a cigarette smoking duration between 3 and 4.59 minutes, while 53.1% of smokers in social settings took > or = 5 minutes to smoke the observed cigarette (chi 2 df 2 = 31.55, p < 0.0001). Smokers who scored at the 75th percentile on the Fagerstrom Tolerance Scale took a mean 9.5 +/- 2.6 puffs per cigarette compared to 9.3 +/- 2.7 puffs by those who scored in the 25th percentile on the scale (t = 0.34, df = 145, p = 0.73). Regardless of degree of nicotine dependency, smokers leaving work-stations to smoke outside buildings smoked their cigarettes nearly 19% "harder" than cigarettes smoked in social settings. The individual and public health benefits of reduced smoking frequency engendered by work-place smoking bans may be lessened by policies which allow smokers to take smoking breaks.     

Effect of culture medium on the in vitro secretion activity of prothoracic glands from Pseudaletia separata

BACKGROUND: Killer lymphocytes secrete perforin, a 67 kDa protein that initiates T-cell cytolysis following aggregation and pore formation in target membranes. The resulting pores cause a breakdown of the transmembrane osmotic gradient and allow other cytolytic mediators to enter the target cell and initiate apoptosis. The cytolytic domain resides within the first 34 residues of the amino terminus of perforin, with residues 1-19 being sufficient for cytolytic activity. RESULTS: The solution structure of a 22-residue synthetic peptide (P22), corresponding to the amino terminus of human perforin, has been determined using high resolution nuclear magnetic resonance spectroscopy in the presence and absence of perdeuterated detergent (SDS) micelles. In aqueous solution, P22 exists mainly in a random conformation. However, it adopts a hook-like structure at the carboxyl terminus in the presence of SDS micelles when the positively charged residues cluster to form a turn that provides a binding surface to the negatively charged sulfate headgroups. CONCLUSIONS: The strong electrostatic interaction between the cationic region of the P22 peptide and the lipid headgroups probably weakens the membrane, facilitating insertion of the relatively neutral/hydrophobic stretch of P22, and is representative of the initial step of the lytic pathway. The structural model described here is probably relevant to understanding the mechanisms of other cationic antimicrobial peptides.     

Effect of weld heat input and creep strain on the elevated temperature and crack growth properties of austenitic steels

A potential material class for use at 600°C and more, e.g. for steam turbines with improved thermal efficiency, are austenitic steels. Using these steels with welded joints, it is to be considered that, by superposition of weld residual stresses and service stresses, extensive creep strains – and in the worst case crack formation – can occur locally. To assess the influence of these effects on service behaviour, different material states of CrNi-steels and Incoloy 800 were investigated with respect to strength, ductility and, especially, to crack and creep crack growth in the temperature range around 600°C. It is shown that creep embrittlement, not microstructural changes as effected by weld heat input, causes heat affected zone (HAZ)-reheat cracking. Creep embrittlement can be avoided by special design and fabrication rules.     

Effect of polyphosphate and sodium chloride on the growth of Listeria monocytogenes and Staphylococcus aureus in ultra-high temperature milk

With UHT-sterilized milk as a model system, combinations of polyphosphate (.5 and 1.0%) and NaCl (.5 and 4.5%) were studied to determine their effects on the growth kinetics of Listeria monocytogenes Scott A and Staphylococcus aureus 196E. The milk was inoculated with 10(3) to 10(4) cfu/ml of either L. monocytogenes or S. aureus and incubated under aerobic conditions at 12, 19, 28, or 37 degrees C. The addition of polyphosphate did not significantly inhibit the growth of either microbe at the temperatures studied, but the addition of NaCl or a combination of salts significantly inhibited growth. The addition of .5 or 1.0% polyphosphate alone to dairy products is not likely to affect substantially the growth of S. aureus or L. monocytogenes.