Time-resolved nanosecond optical pyrometry of the vapor to plasma transitions in exploding bridgewires.

Electrically exploded wires find uses throughout high-energy physics. For example, they are commonly used as high-temperature sources, X-ray generators, and in precision timing detonators. However, the detailed and complete physics that occurs is complex and still poorly understood. A full mechanistic description of these complex phenomena is beyond the scope of a single paper. Instead, we focus on the formation of metal vapor and its transition to plasma. This single transition is commonly assumed to comprise "bridge-burst". We use a suite of diagnostics including a novel, fiber-based, high-speed, optical pyrometer to better characterize this transition. The primary finding from this project is that peak light output from an exploding wire does not temporally match the peak temperature. Additionally, it is found that peak light does not align with peak bridge-burst voltage and that the peak temperature is not voltage-dependent. These findings are non-intuitive and will allow for the correction of false assumptions previously made about this topic.

Cluster analysis of risk factor genetic polymorphisms in Alzheimer's disease.

Multiple genetic variants may contribute to the risk of developing Alzheimer's disease. We have analyzed polymorphisms in 9 genes to determine whether particular combinations would contribute to this risk. The genes were APOE, LDLr, CST3, CTSD, TNF, BACE1, MAPT, STH, eNOS, and TFCP2. Three risk groups for the disease were identified. Risk group I was younger, was heterozygous for the CST3 (GA), CTSD2936 (AG), TNF -308 (AG) genetic variants. Risk group II was older, was homozygous for the -427 APOE promoter polymorphism (TT), and heterozygous for the MAPT deletion and for the STH variant (QR). Group III had both the youngest and oldest subjects, were heterozygous for the -863 (AC) and -1031 (CT) TNF promoter polymorphisms. All three groups carried the APOE 4 allele and were heterozygous for both BACE1 polymorphisms. The control groups were carriers of the APOE 3 allele and were homozygous for the BACE1 genetic variants.

Genetic structure inside a declining red oak community in old-growth forest.

Problems with oak regeneration have been documented in the last 50 years at numerous sites in the Midwestern United States. We applied nuclear microsatellites to examine the demographic and fine-scale spatial genetic structure of red oaks in two old-growth stands in Indiana. Oaks in one stand have declined in numbers over the past several decades whereas oaks in the other, smaller stand have increased. Large amounts of genetic variation were maintained within stands, and there was slight but significant differentiation among stands. There was significant but weak isolation by distance genetic structure within the large stand, likely reflecting family structure. No significant differences exist in allele frequencies or in levels of genetic diversity between cohorts that remain well represented within each stand, even between medium-sized adults and those antedating European settlement of the area. However, a virtual absence of smaller size classes in the forest interior of the large stand represents the early stages of a genetic bottleneck in what had been the core habitat of this stand. Whether future generations of this old-growth stand will retain the present genetic character depends on the oaks regenerating at the forest margins, absent any major changes in disturbance regimes. Similar demographic and genetic dynamics are likely occurring in a large number of remnant oak forests across the Midwest.

Soybean meal from roundup ready or conventional soybeans in diets for growing-finishing swine.

Dehulled soybean meal prepared from genetically modified, herbicide (glyphosate)-tolerant Roundup Ready soybeans containing the CP4 EPSPS protein and near-isogenic conventional soybeans were assessed in an experiment with growing-finishing pigs. The soybeans were grown in the yr 2000 under similar agronomic conditions except that the Roundup Ready soybeans were sprayed with Roundup herbicide. Both were processed at the same plant. The composition of the two types of soybeans and the processed soybean meal were similar. Corn-soybean meal diets containing conventional or Roundup Ready soybean meal and fortified with minerals and vitamins were fed to 100 cross-bred pigs from 24 to 111 kg BW. Diets contained approximately 0.95% lysine initially and were reduced to 0.80 and 0.65% lysine when pigs reached 55 and 87 kg BW, respectively. There were 10 pens (five pens of barrows and five pens of gilts) per treatment with five pigs per pen. All pigs were scanned at 107 kg mean BW and all barrows were killed at the end of the test for carcass measurements and tissue collection. Rate and efficiency of weight gain, scanned backfat and longissimus area, and calculated carcass lean percentage were not different (P > 0.05) for pigs fed diets containing conventional or Roundup Ready soybean meal. Gilts gained slower, but they were more efficient and leaner (P < 0.05) than barrows. Responses to the type of soybean meal were similar for the two sexes with no evidence of a diet x sex interaction for any of the traits. In most instances, carcass traits of barrows were similar for the two types of soybean meal. Longissimus muscle samples from barrows fed conventional soybean meal tended (P = 0.06) to have less fat than those fed Roundup Ready soybean meal, but water, protein, and ash were similar. Sensory scores of cooked longissimus muscles were not influenced (P > 0.05) by diet. The results indicate that Roundup Ready soybean meal is essentially equivalent in composition and nutritional value to conventional soybean meal for growing-finishing pigs.

China's forest policy for the 21st century.

A half-century policy of forest exploitation and monoculture in China has led to disastrous consequences, including degradation of forests and landscapes, loss of biodiversity, unacceptable levels of soil erosion, and catastrophic flooding. A new forest policy had been adopted in China called the Natural Forest conservation Program (NFCP), which emphasizes expansion of natural forests and increasing the productivity of forest plantations. Through locally focused management strategies, biodiversity and forest resources will be sustained, and downstream regions will be better protected from flooding. This new policy is being implemented with a new combination of policy tools, including technical training and education, land management planning, mandatory conversion of marginal farmlands to forest, resettlement and retaining of forest dwellers, share in private ownership, and expanded research. These policy tools may have wider relevance for other countries, particularly developing countries.

Dynamics of induction and expression of long-term synaptic facilitation in Aplysia.

Serotonin (5HT)-induced short-term facilitation and long-term facilitation (STF and LTF) of the monosynaptic connection between tail sensory neurons (SNs) and motor neurons (MNs) in Aplysia have been useful in delineating possible cellular mechanisms contribution to short-term and long-term memory. Previous work from our laboratory showed that LTF can be produced in the absence of STF, suggesting that these processes may be functionally independent. In the present study, we explored this hypothesis by examining the temporal relationship between STF and LTF. We recorded intracellularly from pairs of monosynaptically connected SNs and MNs in isolated pleural-pedal ganglia. In the first experimental series, we followed the time course of LTF across a 24 hr period after its induction by five applications of 10 microM 5HT. STF completely decayed to baseline several hours before the expression of LTF. This biphasic expression profile of STF and LTF further supports the hypothesis that LTF is not a simple elaboration of STF. In the second experimental series, we monitored the immediate expression of facilitation during and after different numbers of 5HT applications. We identified a rapidly decaying STF (lasting 15-30 min) after one to four pulses of 50 microM 5HT and a unique, prolonged intermediate-term facilitation (ITF; lasting up to 90 min) after five pulses of 50 microM 5HT. These results raise the possibility that STF, ITF, and LTF may reflect components of different memory phases in the intact animal.

Efficacy of a recombinant-derived phytase in improving the bioavailability of phosphorus in corn-soybean meal diets for pigs.

Three experiments involving 162 pigs were conducted to assess the efficacy of phytase (Natuphos; BASF, Mount Olive, NJ) in low-P, corn-soybean meal-based diets. The phytase was produced by a recombinant Aspergillus niger. The phytase supplement contained 5,000 phytase units (PTU)/g. In Exp. 1 (66 pigs) and 2 (60 pigs), growing-finishing pigs were fed fortified corn-soybean meal diets formulated to be adequate (.50%), marginal (.425%), or inadequate (.35%) in P during the growing phase (23 to 60 kg BW) followed by adequate (.40%), marginal (.35%), or inadequate (.30%) P, respectively, during the finishing phase (to 104 kg BW). Dicalcium phosphate was the source of supplemental P. In addition, the low-P sequence (.35/.30% P) was supplemented with phytase at 250, 500, or 1,000 PTU/kg. Rate and efficiency of gain decreased linearly (P < .01) and bone breaking strength decreased quadratically (P < .01) as the concentration of P was decreased in the diets. Responses in growth and bone traits to increasing levels of phytase activity in the low-P diet were linear (P < .01). The highest level of phytase in the low-P diet restored growth rate and bone breaking strength to levels that approached or met those of pigs fed the adequate P diet.(ABSTRACT TRUNCATED AT 250 WORDS)

Interviews with children who experienced major life stress: family and child attributes that predict resilient outcomes.

Demographically comparable groups of children exposed to major life-stress, with stress resilient (SR) and stress affected (SA) outcomes at ages 10 to 12, were interviewed to assess perceptions of their caregiving environments, peer relationships, and themselves. SR children compared with SA children reported more: (1) positive relationships with primary caregivers, (2) stable family environments, (3) inductive and consistent family discipline practices, and (4) positive expectations for their futures. SR girls viewed their mothers as more nurturing than did SA girls. Perceptions of fathers, quality of peer relationships, and global self-concept did not differentiate the groups. A discriminant function analysis identified four variables that correctly classified 74% of the subjects as SR or SA. Findings support the view that caregiver-child relationships play a key role in moderating children's developmental outcomes under conditions of high stress.

Developmental and family milieu correlates of resilience in urban children who have experienced major life stress.

Reports findings from interviews with parents of demographically-comparable groups of highly-stressed urban children with stress-resilient (SR) and stress-affected (SA) outcomes at ages 10-12. SR and SA children were compared on family milieu and child development variables assessed within a developmental framework. Compared to SAs, parents of SRs scored higher on variables reflecting parent perceptions of a nurturant caregiver-child relationship and self-views as effective caregivers, in the context of positive discipline practices, a child's positive early temperament, and support for primary caregivers. A discriminant function analysis identified seven variables that optimally differentiated the groups and correctly classified 86% of the Ss as SR or SA.

Stress resilient children in an urban setting.

Overviews the Rochester Child Resilience Project, describes its design and measures, and presents preliminary findings. Within a sample of 313 urban 4th-6th graders, convergent sources of evidence identified subsamples of 37 stress affected (SA) and 40 stress resilient (SR) children, all of whom, based on parent report, had experienced ≥4 stressful life events and circumstances (SLE-Cs). The combined SR/SA groups averaged 8.9 SLE-Cs, significantly more than the rest of the sample. Detailed adjustment ratings by current classroom teachers confirmed that SRs were significantly better adjusted than both SAs and a demographically matched low-stress sample. Factor analysis of the stressful events checklist identified 5 factors. Pooled SRs and SAs had higher scores on these factors than the rest of the sample. In direct comparison of the two groups, SAs had higher scores than SRs only on the Family Separation factor.

Test correlates of stress resilience among urban school children.

Compares subsamples of 37 highly stressed children with stress affected (SA) outcomes and 40 demographically similar children with stress resilient (SR) outcomes, identified within a larger sample of 4th-6th grade urban youngsters. Comparisons were made on a battery of 11 measures believed on conceptual and empirical grounds to have potential for differentiating the groups, in an effort to expand the nomological definitional net for childhood resilience. SR children judged themselves as significantly better adjusted and more competent than SAs. They had higher self esteem, more empathy, and both a more internal and more realistic sense of control. They reported more effective problem solving skills and more positive coping strategies. A combination of five predictor variables used in a discriminant function analysis correctly classified 84.1% of the sample as SRs or SAs.

Isolation from lugworm (Arenicola cristata) of four proteases that activate cyclic AMP phosphodiesterase.

1. Four cyclic AMP phosphodiesterase-activating activities, designated as A, B, C and D, were isolated from lugworm, Arenicola cristata, by preparative flat-bed isoelectric focusing. Activators C and D were further purified by TSK 3000SW HPLC to homogeneity. 2. Activators A, B, C, and D corresponded to pIs of 4.4, 5.0, 5.2 and 5.4; their mol wts were estimated to be 36,200, 30,500, 30,200 and 28,300 respectively. 3. The protease nature of these activities were confirmed by the inhibition by several trypsin inhibitors of their activation of phosphodiesterase and by their hydrolysis of TAME, a synthetic trypsin substrate. Only protease A also hydrolyzed BTEE, a chymotrypsin substrate.

Correlation of log P with molecular connectivity in hydroxyureas: influence of conformational system on log P.

The correlation of log P (in octanol--water) with the nonempirical, topologically dependent, calculated molecular connectivity index (1chiv) delineates substituted hydroxyureas into two families of linearly related groups of compounds. The first group, composed of the 3-substituted ethyl, n-propyl, and n-butyl analogs, is more hydrophilic than the 1-substituted methyl and ethyl and the 3-substituted isopropyl and tert-butyl analogs. The unsubstituted model compound hydroxyurea appears between the two groups in equal volumes of octanol. In octanol--water ratios of 5:1, log P approaches the range of the more hydrophilic group in high concentrations and becomes more lipophilic (similar to the other group) in lower concentrations. The differences in the relative hydrophilicities--lipophilicities of the two groups are rationalized in terms of the equilibri of internally hydrogen-bonded, conformers to those that allow optimal interactions with solvent, water, or other hydroxyurea molecules. The concentration dependency observed with hydroxyurea appears to be due to the ease of interconversion of intermolecularly bonded conformers to those interacting with water, whereas the involvement of internally bonded conformers, which are apparently present to a greater degree in lower concentrations, increases the relative lipophilicity.

Effect of the solvent-dependent conformational system of hydroxyureas on predicted vs. observed log P.

Calculated and observed log P values are reported and compared with in vivo and in vitro biological action (L1210 leukemia ILS % and ribonucleotide reductase ID50) for hydroxyurea, the 1-N methyl and ethyl, and the 3-N ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, phenyl, and p-chlorophenyl analogues. The log P values were calculated via the method of Hansch and Leo from literature f values and the observed log P values were obtained by direct determination after equilibration between octanol and water. Calculations of log P for hydroxyurea were found to be appreciably more hydrophilic than the values obtained experimentally. Differences in calculated and observed log P (delta log P) for the substituted analogues were lowest with the 1-N and the bulky 3-N substituents and greatest with the 3-N-substituted straight-chain analogues (delta log P = 0.70). Different structural species were observed by infrared spectroscopy in dry octanol vs. octanol after water equilibration and drying, and this is proposed as due to changes in conformational equilibrium in the hydroxyurea systems. Differences between calculated and observed log P are explained via the stabilization of internally hydrogen-bonded conformers in the case of 1-N or bulky 3-N analogues or destabilization of various conformers allowing maximal interactions with solvent or water which is the case with straight chain 3-N analogues.

Solvent-dependent conformational system of hydroxyureas in octanol-water and in inhibition of ribonucleotide reductase.

The carbonyl nitrogen IR absorption region of selected hydroxyureas was examined in octanol. The spectra indicated appreciably different absorptions prior to and after equilibration with water. Stability studies on the hydroxyureas indicated that the absorption differences were not due to chemical decomposition in the equilibration process but were due to solvent conformation and/or tautomeric dependency of the system. Preliminary in vitro inhibition of the enzyme ribonucleoside diphosphate reductase by selected hydroxyureas also indicated an apparent solvent dependency, which may involve the conformational and/or tautomeric properties of these agents. The implications of the solvent-dependent conformation-tautomeric system observed are discussed in relation to this property in the biological action of these agents.

Solvent-dependent conformational system in hydroxyureas detected by NMR spectroscopy.

The proton magnetic resonance spectra of the antileukemia agent hydroxyurea and substituted hydroxyureas in several solvents were recorded and correlated with structural features. Solvent-dependent differences in conformational preferences due to effects on internal hydrogen bonding, a temperature-dependent conformational feature, anthe exchangeability of protons with deuterium oxide and acetone-d6 were observed. The conformational features consistent with the spectral data are discussed.