cssi/SciSciGPT-SciSciNet huggingface dataset:
High-resolution structural studies of the retinal--Glu113 interaction in rhodopsin.

Abstract The key to understanding the reaction mechanism of rhodopsin lies in determining the structure of the retinal binding site and in defining the charge interactions between Glu113 and the retinal protonated Schiff base chromophore. We have been using 13 C-NMR chemical shift data to determine the location of the Glu113 carboxyl side chain in relation to the retinal. The NMR data constrain one of the carboxylate oxygens of Glu113 to be ca. 3 A from the C 12 position of the retinal with the second oxygen oriented away from the conjugated chain. A water molecule forming a hydrogen bond with the Schiff base is incorporated into the model to account for the high CN stretching frequency [Han et al., Biophys. J., 65 (1993) 899]. In this study, we have refined the counterion position and have shown that it can reproduce the observed chemical shift data as well as the red-shifted absorption maximum of rhodopsin. Furthermore, the retinal binding site geometry derived from the NMR constraints can be readily incorporated into a recent structural model of the apoprotein.
Information processing, social skill, and gender in schizophrenia.

The relationships among information processing, social skill, and gender in individuals with chronic schizophrenia were investigated. Although there were no gender differences in information processing, social skill, or negative symptoms, performance on information-processing tasks was related to various indices of social skill (e.g., paralinguistic skill) for female, but not male, inpatients. This pattern of results remained after statistical controls were applied for age, illness chronicity, and positive symptoms.
α5-GABAA receptors negatively regulate MYC -amplified medulloblastoma growth

Neural tumors often express neurotransmitter receptors as markers of their developmental lineage. Although these receptors have been well characterized in electrophysiological, developmental and pharmacological settings, their importance in the maintenance and progression of brain tumors and, importantly, the effect of their targeting in brain cancers remains obscure. Here, we demonstrate high levels of GABRA5, which encodes the α5-subunit of the GABAA receptor complex, in aggressive MYC-driven, "Group 3" medulloblastomas. We hypothesized that modulation of α5-GABAA receptors alters medulloblastoma cell survival and monitored biological and electrophysiological responses of GABRA5-expressing medulloblastoma cells upon pharmacological targeting of the GABAA receptor. While antagonists, inverse agonists and non-specific positive allosteric modulators had limited effects on medulloblastoma cells, a highly specific and potent α5-GABAA receptor agonist, QHii066, resulted in marked membrane depolarization and a significant decrease in cell survival. This effect was GABRA5 dependent and mediated through the induction of apoptosis as well as accumulation of cells in S and G2 phases of the cell cycle. Chemical genomic profiling of QHii066-treated medulloblastoma cells confirmed inhibition of MYC-related transcriptional activity and revealed an enrichment of HOXA5 target gene expression. siRNA-mediated knockdown of HOXA5 markedly blunted the response of medulloblastoma cells to QHii066. Furthermore, QHii066 sensitized GABRA5 positive medulloblastoma cells to radiation and chemotherapy consistent with the role of HOXA5 in directly regulating p53 expression and inducing apoptosis. Thus, our results provide novel insights into the synthetic lethal nature of α5-GABAA receptor activation in MYC-driven/Group 3 medulloblastomas and propose its targeting as a novel strategy for the management of this highly aggressive tumor.
Chronic electrical stimulation by a cochlear implant promotes survival of spiral ganglion neurons after neonatal deafness.

This investigation examined the consequences of neonatal deafness and chronic intracochlear electrical stimulation delivered by a cochlear implant during maturation. Kittens were bilaterally deafened by an ototoxic drug administered daily for 2 weeks immediately after birth. Unilateral electrical stimulation was initiated at 7–10 weeks of age and continued over periods of 22–47 weeks (4 hours/day; 5 days/week). Bipolar intracochlear electrodes delivered one of several different electrical signals designed to be temporally challenging to the central auditory system. Morphometric evaluation of spiral ganglion (SG) cell somata within Rosenthal's canal demonstrated a mean of ≈50% of normal cell density maintained in the chronically stimulated ears, compared with ≈30% on the control deafened side. This 20% difference in density was highly significant and was greater than differences reported in earlier studies using 30 pps stimulation delivered by either intracochlear bipolar or round window monopolar electrodes. However, the duration of stimulation was also longer in the present study, so it is unclear to what extent the nature of the temporally challenging stimulation vs. its duration contributed to the marked increase in survival. Measurements of the SG cell somata revealed a pronounced decrease in cell diameter in neonatally deafened cats studied about 1 year after deafening, and an additional decrease after long-term deafness (2.5–6.5 years). Furthermore, in the cochlear regions with the greatest stimulation-induced differences in SG cell density, direct measurements of cross-sectional soma area of the largest cells revealed that cells were significantly larger in the stimulated ears. Thus, in addition to the marked increase in the number of surviving SG cells, larger soma area contributed modestly to the pronounced increase in neural density following chronic electrical stimulation. J. Comp. Neurol. 412:543–562, 1999. © 1999 Wiley-Liss, Inc.
Differential effects of hospital case mix on hospital costs and revenues, with a focus on Medicaid patients

Hospitals in California have argued that because of hospital competition and managed care, their costs have increased faster than their revenues. By developing a payer-specific Case Mix Index (CMI) for Medi-Cal, California's Medicaid programme, this study attempts to test the hospitals' argument. Using California hospitals' financial and utilisation data for selected years from 1986 through 1998, this study finds that the coefficients for Medi-Cal CMIs in the hospital inpatient revenue model were greater than those in the hospital inpatient cost model until 1995. Since 1995, however, the coefficients of CMIs in the cost model have been greater than those in the revenue model. Thus, by focusing on the payer-specific CMI for Medi-Cal, this study reveals that in the later years the rate of increase for hospital inpatient costs of Medi-Cal patients has been greater than that for hospital inpatient revenues. The claim the hospitals are making may be warranted for the years since 1995 for Medi-Cal patients.
Pearl Millet as a Rotation Crop for Peanut

Abstract In the southeastern United States, there are limited options for crops that can be grown in rotation with peanut (Arachis hypogaea). Pearl millet (Pennisetum glaucum) has potential as a gr...
An Observational Study of Easterly Waves over the Eastern Pacific in the Northern Summer Using FGGE Data

Abstract FGGE revel III-b data provided by the European Centre for Medium-Range Weather Forecasts and the outgoing longwave radiation data measured by satellites are used to investigate observationally relationships between deep cloud activity and large-scale meteorological fields during the Northern Hemisphere summer (May–September) of 1979 over the eastern Pacific. Aside from the summer monsoon area over southern and eastern Asia, the eastern Pacific is the area where strong, deep convection frequently develops in the northern summer. This is also one of the tropical ocean areas that have been least explored meteorologically. A power spectral analysis using the Maximum Entropy Method is made for the meridional wind component at 850 mb at various grid points in the analysis domain for each mouth from May through September. The waves with a period of 4–6 days are not only stronger in July and August than those of other months, but active in the regions of 100°–130°W in the eastern Pacific and 130°–160°E i...
Influences on Sino-Western joint venture negotiations

This paper attempts to increase the reader's knowledge of the influences present when negotiating in China. The current environment of Sino-Western joint venture (JV) negotiations is examined, and negotiating suggestions resulting from this examination are presented. The paper, the result of the author's research in China in 1987–1989, posits that the major influences on Sino-Western JV negotiations are the ideological and theoretical foundations for such JVs, their history, the problems they experience, and the political, economic, governmental, and cultural contexts of negotiations. The paper's importance lies in two areas: it contributes to the literature on the international transfer of capital and technology, and it provides valuable information to Western firms and individuals who consider entering into JV negotiations in China.
Au10−: isomerism and structure-dependent O2 reactivity

Structure isomers of the Au10− cluster and their chemical reactivity with O2 are studied using photoelectron spectroscopy under different experimental conditions. In addition to the global minimum triangular D3h structure, at least three low-lying isomers (X′, X″, and X‴) are observed distinctly using argon tagging and O2 titration. The D3h structure has a very high electron affinity of 3.88 eV, whereas the low-lying isomers have lower electron affinities (2.86, 3.09, and 3.45 eV for X′, X″, and X‴, respectively). It is found that the D3h global minimum does not react with O2 and can only form a physisorbed Au10(O2)− van der Waals complex under cold experimental conditions. The three low-lying isomers are reactive with O2 and can be systematically titrated out of the cluster beam using an O2-seeded carrier gas, leaving a clean D3h Au10− beam.
A multiperiod planning model for communications satellites

Abstract The wide range of choices in technology and service offerings, increased competition, and uncertainty in the operating environment has led to significantly increased interest in the economics of communication satellites. In this paper, we develop a multiperiod planning model to help analyze the viability of decisions on key physical and operational parameters, for a satellite intended to provide Customer Premise Services. The reversed geometric programming CPS model captures interactions and tradeoffs among technical variables as well as effects of market prices for transmission capacity, physical and regulatory constraints. It can be used to analyze effects of variability in future demand and prices on the satellite configuration and its economic viability, thus providing useful information during the planning phase.
Detection of Phenol and Benzoate as Intermediates of Anaerobic Benzene Biodegradation under Different Terminal Electron-Accepting Conditions

A sulfate-reducing bacterial enrichment that anaerobically metabolized benzene was obtained from a petroleum-contaminated aquifer. During biodegradation, we observed the transient accumulation of p...
Electron waveguide devices

The discovery of electron waveguiding in one-dimensional (1D) semiconductor nanostructures has uncovered a new regime of electron transport with fascinating physics. The device potential of electron waveguides, however, remains largely unexplored. Over the last few years, our interuniversity team has been conducting research on the physics, technology and opportunities for device applications of split-gate AlGaAs/GaAs electron waveguides. We have examined electronic devices based on electron transport, tunneling and interference. Many problems have been identified in transport-type devices, but much more research is required before the engineering potential of tunneling and interference devices is understood. We have also investigated the potential of electron waveguides in photonic applications, with emphasis on far-infrared (or THz) photodetectors. Our research to date has revealed strong photon-induced currents in antenna-coupled electron waveguides that arise from quantum thermopower. Far-infrared photodetectors based on photon-induced quantum transport remain an interesting opportunity for the application of electron waveguides.
Single subject experimentation for psychiatric nursing

Mental health nurses encounter countless opportunities to assess medication and intervention efficacy but often find themselves relying solely on descriptive case study accounts and familiar group comparison methodology. Although case studies are useful, they lack scientific rigor and group comparison designs may not be suited to certain client populations or research questions that address individual client characteristics. The purpose of this article is to describe single subject experimentation, contrast this approach with case study and group comparison designs, and discuss how this type of scientific inquiry can be incorporated in psychiatric nursing practice.
MiniBooNE oscillation searches

The range of oscillation analyses being pursued by the MiniBooNE collaboration is described. Focus is given to the various searches for electron neutrino appearance, but the disappearance of muon neutrinos and the appearance search for electron anti-neutrinos are covered as well.
A sparse algorithm for predicated global value numbering

This paper presents a new algorithm for performing global value numbering on a routine in static single assignment form. Our algorithm has all the strengths of the most powerful existing practical methods of global value numbering; it unifies optimistic value numbering with constant folding, algebraic simplification and unreachable code elimination. It goes beyond existing methods by unifying optimistic value numbering with further analyses: it canonicalizes the structure of expressions in order to expose more congruences by performing global reassociation, it exploits the congruences induced by the predicates of conditional jumps (predicate inference and value inference), and it associates the arguments of acyclic o functions with the predicates controlling their arrival (o predication), thus enabling congruence finding on conditional control structures. Finally, it implements an efficient sparse formulation and offers a range of tradeoffs between compilation time and optimization strength. We describe an implementation of the algorithm and present measurements of its strength and efficiency collected when optimizing the SPEC CINT2000 C benchmarks.
Examining the Chirality, Conformation and Selective Kinase Inhibition of 3-((3R,4R)-4-methyl-3-(methyl(7H-pyrrolo[2,3-d]pyrimidin-4-yl)amino)piperidin-1-yl)-3-oxopropanenitrile (CP-690,550)

Here, we examine the significance that stereochemistry plays within the clinically relevant Janus kinase 3 (Jak3) inhibitor 1 (CP-690,550). A synthesis of all four enantiopure stereoisomers of the drug was carried out and an examination of each compound revealed that only the enantiopure 3R,4R isomer was capable of blocking Stat5 phosphorylation (Jak3 dependent). Each compound was profiled across a panel of over 350 kinases, which revealed a high level of selectivity for the Jak family kinases for these related compounds. Each stereoisomer retained a degree of binding to Jak3 and Jak2 and the 3R,4S and 3S,4R stereoisomers were further revealed to have binding affinity for selected members of the STE7 and STE20 subfamily of kinases. Finally, an appraisal of the minimum energy conformation of each stereoisomer and molecular docking at Jak3 was performed in an effort to better understand each compounds selectivity and potency profiles.
Synthesis and characterization of interpenetrating polymer networks for nonlinear optics

Two-component simultaneous interpenetrating networks (IPN) of thepoly(4′-[[2-(methylacryloxy)ethyl]ethylamino]-4-nitroazobenzene-co-methyl meth-acrylate) (PDR1MA-co-MMA)/poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) system, the PDR1MA/PPO system and 4′-[[2-(acetoxy)ethyl]ethylamino]-4-nitroazo benzene (ACDR1) doped MMA/PPO system were synthesized and characterized. As studied by differential scanning calorimetry (DSC) the full IPNs of the PDR1MA-co-MMA/PPO system and the PDR1MA/PPO system showed a single Tg varying with the PPO composition. A single-phase morphology of the full IPNs was also indicated by scanning electron microscopy (SEM). Transparent films were cast onto clean microscopic glass slides and poled at 190°C for 1 h. The UV-VIS absorption spectra of the three IPN systems before and after curing and corona poling showed a shift in the maximum absorption due to the induced alignment of the nonlinear optical chromophores in the IPN systems. The absorption intensity of the full IPNs remained same after heating at 120°C for 72 h, indicating that the electric field-induced alignment is stable in the full IPN materials. Preliminary second harmonic generation (SHG) data on these IPNs are presented. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 553–561, 1998
Reactions within p-Difluorobenzene/Methanol Heterocluster Ions: A Detailed Experimental and Theoretical Investigation

The reactivity of p-difluorobenzene/methanol cluster ions has been investigated by using triple quadrupole mass spectrometry and DFT calculations. The present study was performed in light of a recent investigation of p-difluorobenzene/methanol (P = F-C(6)H(4)-F and M = CH(3)OH) heterocluster ions where the solvent-catalyzed formation of p-fluoroanisole (A = CH(3)O-C(6)H(4)-F) was observed in P(M)(2)(+) clusters and not in PM(+) clusters. The results of our mass selected cluster ion study and theoretical calculations confirm that a single extra molecule of methanol can lower the reaction activation energy barrier in agreement with previous work for smaller clusters (PM(+) and P(M)(2)(+)). However, we also observe that P(M)(3)(+) and P(M)(4)(+) clusters undergo evaporative loss of neutral methanol to establish the P(M)(2)(+) cluster before reacting. P(M)(n>4)(+) clusters are capable of reacting through multiple pathways, in some cases generating a 1,4-dimethoxybenzene (B = CH(3)O-C(6)H(4)-OCH(3)) product via two separate substitution reactions within the same cluster ion. DFT calculations were employed to model the structures of the parent cluster ions, and transition state calculations were used to evaluate the activation energy for the p-fluoroanisole-forming substitution reaction. The calculations suggest that the reaction proceeds through a transition state containing a six-member hydrogen-bonded ring involving a reacting methanol and a second methanol that significantly lowers the activation energy.
Compact, narrow-linewidth, tunable ultraviolet laser source for detecting Hg emissions

Recent EPA regulations targeting mercury (Hg) emissions from utility coal boilers have prompted increased activity in the development of reliable chemical sensors for monitoring Hg emissions with high sensitivity, high specificity, and fast time response. We are developing a portable, laser-based instrument for real-time, stand-off detection of Hg emissions that involves exciting the Hg (6 3P1 ←6 1S0) transition at 253.7 nm and detecting the resulting resonant emission from Hg (6 3P1). The laser for this approach must be tunable over the Hg absorption line at 253.7 nm, while system performance modeling has indicated a desired output pulse energy ≥0.1 μJ and linewidth ≤5 GHz (full width at half-maximum, FWHM). In addition, the laser must have the requisite physical characteristics for use in coal-fired power plants. To meet these criteria, we are pursing a multistage frequency-conversion scheme involving an optical parametric amplifier (OPA). The OPA is pumped by the frequency-doubled output of a passively Q-switched, monolithic Nd:YAG micro-laser operating at 10-Hz repetition rate and is seeded by a 761-nm, cw distributed-feedback diode laser. The resultant pulse-amplified seed beam is frequency tripled in two nonlinear frequency-conversion steps to generate 253.7-nm light. The laser system is mounted on a 45.7 cm × 30.5 cm breadboard and can be further condensed using custom optical mounts. Based on simulations of the nonlinear frequency-conversion processes and current results, we expect this laser architecture to exceed the desired pulse energy. Moreover, this approach provides a compact, all-solid- state source of tunable, narrow-linewidth visible and ultraviolet radiation, which is required for many chemical sensing applications.© (2008) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
A data-oriented introduction to program design

Stepwise refinement is an invaluable analytic tool for solving complex problems, but it is somewhat artificial for the simple problems encountered in the first half of an introductory programming course. This paper describes an alternate process which still provides for a gradual transition from a problem to an algorithm which solves the problem. Each algorithm, which is unambiguous and English-like, is synthesized from sample data and can be routinely translated into a (structured) program.
Colorectal Cancer in Hereditary Breast Cancer Kindreds

PURPOSE: This study compared characteristics of colorectal cancer between families with dominant breast cancer inheritance and the general population. The cumulative incidence of colorectal cancer was also studied in genetically determined breast cancer syndrome subjects with BRCA1 and BRCA2 mutations and compared with the general population. METHODS: Subjects included 42 patients with colorectal cancer from 32 clinically determined hereditary breast cancer kindreds based on the autosomal dominant inheritance of breast cancers and early age of onset. The general population colorectal cancer cohort was composed of 755 patients from a tumor registry. Lifetime risk of colorectal cancer was determined in 164 BRCA1 and 88 BRCA2 gene mutation carriers and compared with the general population. Mean age of colorectal cancer onset, anatomic site distribution, histologic stage at presentation, and five year stage-stratified survival rates were compared between clinically determined hereditary breast cancer family members and the general population. RESULTS: The lifetime risk of colorectal cancer in male BRCA1 and BRCA2 mutation carriers was 5.6 percent, which was not different from 6 percent in males from the general population. Likewise, the lifetime colorectal cancer risk in female BRCA1 and BRCA2 mutation carriers was 3.2 percent, which was not different from 5.9 percent in females from the general population. Mean age of onset ± standard error for patients with colorectal cancer was 60±2 years for hereditary breast cancer kindreds compared with 67±0.4 years for the general population (P=0.0004). Colorectal cancer site distribution did not vary between hereditary breast cancer and the general population. Overall colorectal cancer stage distribution was significantly different, with more Stage I and fewer Stage IV cancers in subjects with hereditary breast cancer compared with the general population (P=0.01). Overall five year stage-stratified colorectal cancer survival rate ± standard error was 66±8 percent for hereditary breast cancer kindreds and 46±2 percent for the general population (P=0.023). CONCLUSION: Lifetime cumulative colorectal cancer incidence in subjects with BRCA1 and BRCA2 gene mutations was not different from the general population. However, significant differences in colorectal cancer were noted between hereditary breast cancer family members and the general population. Hereditary breast cancer-associated colorectal cancer had an earlier age of onset, lower tumor stage, and better survival rate than the general population. Except for age of onset, colorectal cancer in hereditary breast cancer kindreds exhibited more favorable characteristics than colorectal cancer in the general population.
Continuum modeling of plastic flow localization in irradiated fcc metals

Abstract Under mechanical loading, neutron or ion irradiated metals may develop a mechanical instability characterized by the localization of plastic flow in narrow channels that are cleared of irradiation-induced defects. The resulting highly heterogeneous deformation can play a significant role in crack nucleation, fracture propagation, and premature failure of structural components used in nuclear applications. In this work, we develop a two-dimensional continuum model of plastic flow localization based on the continuum theory of dislocations. This framework allows a mechanism-based description of deformation in which plastic distortion is directly calculated from the evolution of dislocation density tensor fields on each slip system. The dislocation densities mutually interact through the self-consistent stress field derived from the deformation gradient and through back and flow stress corrections. The interaction between dislocation fields and irradiation-induced defects (mainly stacking fault tetrahedra (SFTs) in fcc metals) is twofold. First, the flow stress depends locally on the SFT density. Second, and based on existing molecular dynamics (MD) simulation results, dislocation fluxes are included as sink terms in the evolution equation of the SFT density. The model is implemented numerically using the finite element method (FEM) and simulation results for simple shear loading are presented. It is demonstrated here that small spatial fluctuations in the density of SFTs, coupled with their destruction by dislocation interaction, leads to plastic flow localization.
Racial Diversity, Representative Bureaucracy, and Equity in Multiracial School Districts*

Objective. This study examines the conditions under which minorities will face policy inequity within the educational system. It turns to the theory of representative bureaucracy as one possible explanation, and extends the literature by considering whether African-American students benefit from the presence of Latinos on teaching faculties and vice versa. This study also tests competing theories of how racial context influences minority educational policy outcomes. Methods. This study combines original survey data with data gathered by the U.S. Census to predict levels of academic grouping in U.S. school districts as reported by the Office of Civil Rights. Results. Minority teachers lower levels of discrimination among all minority students, not just co-ethnics. Moreover, minority teachers do so consistently and with a substantive impact that occasionally rivals that of co-ethnic teachers. The findings also suggest that greater levels of racial/ethnic diversity within a district are associated with lower levels of discrimination. Conclusion. Theories of race relations must move beyond black-Anglo or Latino-Anglo relations to consider how multiple racial/ethnic groups interact, and how such interactions affect the lives of minority groups differently.
Abnormal reinnervation as a basis for schizophrenia: a hypothesis.

• Neuropathologic and neuroimaging studies reveal atrophy or dystrophy of the hippocampal region and enlarged ventricles indicative of tissue loss in many patients with schizophrenia. It is now widely recognized that brain damage can provoke regenerative collateral sprouting of axons, synaptic proliferation, and reorganization, even in the adult mammalian brain. The functional consequences of these plastic regenerative changes are largely unknown; they could be adaptive or cause further impairment. There is evidence of lesion-provoked aberrant synaptic regeneration in epilepsy and Alzheimer's disease. Data suggest that anomalous reinnervation could also have a significant role in the pathophysiology of schizophrenia. Histologic methods to test this hypothesis are in progress.
Catalytic Activity of Platinum Monolayer on Iridium and Rhenium Alloy Nanoparticles for the Oxygen Reduction Reaction

A new type of electrocatalyst with a core–shell structure that consists of a platinum monolayer shell placed on an iridium–rhenium nanoparticle core or platinum and palladium bilayer shell deposited on that core has been prepared and tested for electrocatalytic activity for the oxygen reduction reaction. Carbon-supported iridium–rhenium alloy nanoparticles with several different molar ratios of Ir to Re were prepared by reducing metal chlorides dispersed on Vulcan carbon with hydrogen gas at 400 °C for 1 h. These catalysts showed specific electrocatalytic activity for oxygen reduction reaction comparable to that of platinum. The activities of PtML/PdML/Ir2Re1, PtML/Pd2layers/Ir2Re1, and PtML/Pd2layers/Ir7Re3 catalysts were, in fact, better than that of conventional platinum electrocatalysts, and their mass activities exceeded the 2015 DOE target. Our density functional theory calculations revealed that the molar ratio of Ir to Re affects the binding strength of adsorbed OH and, thereby, the O2 reduction a...
FIGHTING AN EPIDEMIC: THE ROLE OF SCHOOLS IN REDUCING CHILDHOOD OBESITY

Obesity among children and adolescents is a major public health concern affecting the physical and emotional health of youth while increasing their risk of reduced quality and duration of life. Schools and communities have begun to galvanize to address this epidemic and need quality empirical information to guide their policy, programming, and intervention efforts. This article reviews the definition of childhood obesity and the physical, psychosocial, and academic consequences of obesity among youth. The roles of schools and school psychologists in intervening against this overwhelming trend are discussed as well as current empirically based programs. Schools are recommended to take a comprehensive, multifaceted approach to school policies and programs to increase nutrition and physical activity. © 2006 Wiley Periodicals, Inc. Psychol Schs 43: 361–376, 2006.
Developmental expression of cocaine hepatotoxicity in the mouse

Abstract Cocaine may be metabolized either by ester hydrolysis to inactive products or by oxidation via a cytochrome P-450 and FAD-monooxygenase pathway to a hepatotoxic metabolite, presumably norcocaine nitroxide. Mice are the species most susceptible to cocaine-induced hepatotoxicity (CIH), and marked strain differences in response have been found. Female mice are very resistant to CIH, whereas males are susceptible, indicating that hormonal factors may be involved. We treated mice of 5 inbred strains with cocaine at three ages: 20 days (weanling), 30 days (adolescent) and 60 days (adult). The CIH response was assessed by measurement of plasma alanine aminotransferase (ALT) activity 18 hours later. For each of the strains females of all three are groups were resistant to CIH, and males did not begin to develop CIH until approximately 30 days of age. The degree of CIH in 30-day-old males was intermediate between the levels found in 20-day-old males and adult males. These data suggest that the enzyme, or enzymes, responsible for the production of the toxic metabolite are absent, or at very low levels, in female and immature male mice, and that they are either inducible by androgens or are repressed by estrogens or progestins. It is possible that these enzymes may be involved in the production of toxic metabolites of compounds other than cocaine.
Fecundity, autogeny, and the larval environment of the pitcher-plant mosquito, Wyeomyia smithii.

Pupae and fourth instar larvae of a southern (30°N, Alabama, USA) population of Wyeomyia smithii Coq. (Diptera: Culicidae) were collected from pitcher plants. Adults which emerged were maintained without food then dissected to determine their egg clutch size. Among females which matured eggs, fecundities were negatively correlated with larval densities in individual pitchers. The mean autogenous fecundity of the overwintering generation did not differ from a summer sample. Adults unable to mature eggs comprised 6–39% of samples, depending on whether collected as pupae or fourth instar larvae. Fecundity was negatively correlated with time to adult eclosion among larvae maintained on unrenewed pitcher contents in the laboratory. Cohorts from this population were reared in artificial containers from egg hatch to adulthood at a single density and a superior or inferior diet. On the superior larval diet, all females survived to reproductive age, and all but one (>99%) produced eggs autogenously. On the inferior diet, survivorship to adult eclosion was significantly less, a high proportion of females died before reaching reproductive age, and only 19% of survivors matured eggs without blood. Protracted larval development induced by the inferior diet did not influence the probability of autogeny among females that survived to reproductive maturity. The relationship between larval environment and reproductive strategies is contrasted across the geographic range of W. smithii. Bloodfeeding occurs among southern populations where density dependent constraints on preimaginal growth are constantly severe. The loss of hematophagy among northern populations may have been facilitated by periods of density independent larval growth.
Molecular consequences of specific intron mutations on yeast mRNA splicing in vivo and in vitro

We have altered the TACTAAC sequence in the yeast CYH2m gene intron to TACTACC. This mutation changes the nucleotide at the normal position of the branch in intron RNA lariats produced during pre-mRNA splicing, and it prevents splicing in vivo. In a yeast pre-mRNA splicing system, CYH2m pre-mRNA carrying the TACTACC mutation is not specifically cut or rearranged in any way. Substitution of an A for the first G of the CYH2m intron, converting the highly conserved GTATGT 5' splice site sequence to ATATGT, also blocks intron excision in vivo and in vitro: pre-mRNA carrying this mutation was still cut normally at the mutant 5' splice site in vitro, to give authentic exon 1 and an intron-exon 2 lariat RNA with an A-A 2'-5' phosphodiester linkage at the branch point. This lariat RNA is a dead-end product. The subsequent cleavage at the 3' splice site is therefore sensitive to the sequence of the 5' end of the intron attached at the branch point.
The High Temperature Superconductivity Space Experiment: HTSSE I-Components and HTSSE II-Subsystems and advanced devices

The goals and objectives of the High Temperature Superconductivity Space Experimental (HTSSE) program are described, and a description of the first launch package and plans for future experiments (HTSSE-II) are presented. The objective of the program is to prove that HTS technology is sufficiently robust to survive the space environment and that it has the potential to significantly improve space communications systems. The devices for the initial launch (HTSSE-I) have been delivered to US Naval Research Laboratory, their electrical characteristics have been verified, and their packages have been space-qualified. These devices will be integrated with a cryogenic refrigeration system and a data acquisition system, all space-qualified. Once placed in earth orbit, the experimental package will be cooled to cryogenic temperatures and the characteristics of the HTS devices monitored periodically. The HTSSE-I mission, scheduled to start in 1993, will last for at least six months. >
The U.S. health data privacy debate. Will there be comprehension before closure

After 25 years of debate about privacy of automated personal health data, the U.S. Congress has set a deadline of August 1999 for enacting health information privacy legislation. The urgency to establish national policy in the United States re-emerges with implementation of a 1996 law mandating a unique identifier for each participant in the U.S. medical care system and the use of a uniform electronic data set for all health information transmitted in financial and administrative transactions. The impact of electronic data storage and transmittal on privacy, health outcomes, and medical care is unclear. A three-step analytic scheme can clarify the issues in the policy debate and for future assessment. The first step is intended to elicit, for the first time, a precise, accurate, and reproducible description of personal health data transactions and chains of transactions, independent of the policy preferences of any interested party. The second step allows the reader to analyze these transactions according to who benefits first and foremost from each. This scrutiny clarifies the reasons why parties to the debate tend to disagree. The third step characterizes how Congress is likely to perceive the policy process and consider its options before enacting any particular set of compromises. Understanding the policy deliberations and potential effects of evolving information technologies and new national privacy rules should aid assessment of results.
The role of parental language acculturation in the formation of social capital: differential effects on high-risk children.

This person-centered study examines the extent to which parents’ language dominance influences the effects of an after school, multi-family group intervention, FAST, on low-income children’s emotional and behavioral outcomes via parents’ relations with other parents and with school staff. Social capital resides in relationships of trust and shared expectations, which are highly dependent on whether parents share the language of other parents and teachers. This study is based on a community epidemiologically-defined sample of Latino families (N = 3,091) in San Antonio, Texas and Phoenix, Arizona. Latent profile analyses revealed three language profiles of parents across the two cities: English-dominant, Spanish-dominant, and bilingual. Path models revealed that FAST did not have a direct or indirect effect on children’s emotional and behavior functioning, although FAST increased parent–parent and parent-school social capital among Spanish-dominant parents in Arizona and these parent–parent relations were associated with better child outcomes. Implications for interventions are discussed.
Structure of a fluorinated azoxy compound: fluoro(trifluoromethyl)-diazene-2-oxide, CF3N(O)NF.

A gas-phase electron diffraction study of the azoxy compound which was synthesized by the reaction of CF3NO with N2F4 in a Pyrex glass vessel results in a trans CF3N(O)NF structure (F trans to CF3), although quantum chemical calculations (MP2 and B3LYP) predict a greater stability of the cis CF3NN(O)F isomer by about 12 kcal/mol. The CF3 group eclipses the NN double bond. The following skeletal geometric parameters (ra values with 3σ uncertainties) were obtained: NN 1.287(15) A; NO 1.231(6) A; NF 1.380(6) A; NC 1.498(6) A; NNO 131.2(13)°; NNF 103.5(13)°; NNC 114.0(12)°. The bond lengths in CF3N(O)NF are compared to those in azo, nitryl, and nitrosyl compounds with fluorine and/or CF3 substituents.
Selective integration of avian leukosis virus in different hematopoietic tissues

Hematopoietic tissues obtained from avian leukosis virus (ALV)-infected Hyline SC chickens were analyzed for the presence of integrated viral DNA sequences. Cells were prepared from bone marrow, bursa, spleen, thymus, and peripheral blood. Following the removal of erythrocytes, cellular DNAs from each of these tissues were examined by Southern analysis. During the first few weeks of infection, DNA from the bone marrow contained as many as 0.5 copies of viral DNA per haploid genome. Cells from the bursa and peripheral blood contained between 0.05 and 0.15 copies per haploid genome. In contrast, neither splenic nor thymic DNA contained significant levels of viral DNA sequences even though infected birds developed titers of circulating virus between 10(5) and 10(6) IU/ml of plasma. DNA prepared from erythrocytes isolated from the peripheral blood of these birds contained approximately 0.4 copies of integrated viral sequences per haploid genome at 2 weeks after infection. Despite greater levels of integrated sequences in other tissues, by 9 weeks after infection viral sequences were detected only in DNA from bursal lymphocytes. Cells prepared from the spleen and thymus of infected birds were also examined for their size distribution, their internal complexity and their surface expression of immunoglobulin. None of the populations examined differed from normal, uninfected control preparations. These results suggest that ALV infection occurs primarily in the bone marrow and that the different tissues of the hematopoietic system are selectively infected. Further, these results indicate that ALV infection persists longer in bursal lymphocytes than in other hematopoietic tissues. Previous studies have demonstrated that the lymphoid tumors that develop in white leghorn chickens following ALV infection are bursal-dependent B-cell lymphomas that express immunoglobulin M. The observations presented in this communication offer, in part, an explanation for the restricted phenotype of the lymphoid tumor that develops in the SC chicken. Further, the data suggest an explanation for the bursal-dependent nature of the ALV-induced lymphoma.
Can Common Sense Effectively Guide the Behavior of Beginning Teachers

Common sense cannot and must not serve as the basis for professional prac tice, argues Haberman. Indeed, some common sense is nonsense; and some teachers who are well-educated and well-intentioned,...
The Darkest Bright Star: Chandra X-Ray Observations of Vega

We present X-ray observations of Vega obtained with the Chandra High Resolution Camera and Advanced CCD Imaging Spectrometer. After a total of 29 ks of observation with Chandra, X-rays from Vega remain undetected. We derive upper limits to the X-ray luminosity of Vega as a function of temperature over the range of 105-107 K and find a 99.7% upper limit as low as ~2 × 1025 ergs s-1 at T = 106.2 K. We also compare these new deeper observations with the limit derived from a reanalysis of ROSAT PSPC data. Our X-ray luminosity limit for Vega is still greater than predictions of post-Herbig Ae phase X-rays from the shear dynamo model proposed by Tout & Pringle for a Vega age of 350 Myr. If the age of Vega is closer to 100 Myr, as suggested by some indicators, our X-ray limit is then similar to Tout-Pringle model predictions. Current X-ray observations of Vega are therefore unable to discriminate between different scenarios explaining the X-ray activity of the convectively stable Herbig Ae/Be stars. Further progress is more likely to be achieved through X-ray observations of younger main-sequence early-type A stars, whose conjectured residual post-Herbig Ae phase X-ray activity would be significantly higher.
The active nightlife of diurnal birds: extraterritorial forays and nocturnal activity patterns

Most birds are socially monogamous, diurnally active and have small home ranges. These birds occasionally undertake extraterritorial forays, presumably to seek extrapair copulations. We used automated radiotelemetry to examine nocturnal forays and activity of a diurnal, socially monogamous passerine, the yellow-breasted chat, Icterina virens. Males and females forayed during both day and night, but night forays were more common. In addition to varying between day and night, there were sex- and breeding-stage-specific differences in foraying behaviour. Males forayed more than females and more frequently when their female was not fertile. Conversely, females primarily forayed when fertile. We suggest that females foray at night to avoid detection, because their mate's knowledge of potential extrapair copulations may result in harassment or decreased parental care. Both sexes were nocturnally active; however, the activity of males peaked when their mates were fertile, probably to prevent their mates from foraying and guarding them from foraying males. The nocturnal behaviour of chats suggest that extraterritorial forays may be more common than previously thought and that nocturnal behaviours may be crucial for understanding the strategies males and females use to acquire extrapair copulations.
Can family attributes explain the racial disparity in living kidney donation

Abstract Background Living donation is a safe, effective treatment for patients with end-stage renal disease (ESRD), yet rates of live kidney donation remain low. Potential transplant recipients may be more inclined to ask a family member for a living donation if they feel familial closeness. Methods The FACES II and the Living Organ Donor Survey were administered to patients attending pretransplant education to assess individual perceptions of family structure and willingness to request a living kidney donation from a family member. Results A total of 328 potential transplant recipients were included in the study: 200 (61%) African American and 128 (39%) Caucasian. Approximately half were willing to ask for a living donation. Individual’s perception of family cohesion, adaptability, and type as measured by FACES II showed most families were mid-range with optimal cohesion and adaptability. Family cohesion and adaptability showed no association with being willing to request a live donation, but those single/never married were only half as likely to ask for donation (odds Ratio [OR] 0.51; 95% confidence interval [CI] 0.31–0.86, P = .01). Lower education (β = −0.49) and unmarried status (β = −0.31) predicted a lower cohesion score. Conclusion Family type, cohesion, and adaptability showed no differences across race and was not related to the potential recipient’s willingness to ask for a live donation. Although responses by race did not differ, an important finding showed that only half of ESRD patients are willing to ask for a live organ donation, and those patients that were single/never married were less likely to ask for a living donation. Research surrounding this reluctance is warranted.
High-frequency nasal ventilation for 21 d maintains gas exchange with lower respiratory pressures and promotes alveolarization in preterm lambs.

High-frequency nasal ventilation for 21 d maintains gas exchange with lower respiratory pressures and promotes alveolarization in preterm lambs
Transplantation of pig stem cells into rat brain: proliferation during the first 8 weeks

Previous work indicated that pig umbilical cord matrix (pUCM) cells are a type of primitive stem cell and that these cells could be recovered after central or peripheral injection into rats that did not receive immune suppression therapy. To determine the safety and proliferation potential of pUCM cells after brain transplantation, approximately 150 pUCM cells were transplanted into the brains of rats that previously received a striatal injection of the neurotoxin 6-hydroxydopamine (6-OHDA). The pUCM cells were previously engineered to express enhanced green fluorescent protein (eGFP); in this way, the graft cells were identified. The rats did not receive immune suppression therapy. There were no postsurgical complications and the animals thrived following transplantation. At 2, 4, 6, and 8 weeks after transplantation, two rats were sacrificed and the morphology, size and number of graft cells, and the percentage of tyrosine hydroxylase (TH)-positive graft cells were determined. The size distribution of the grafted pUCM cells was unimodal and normal, and the average size increased significantly over the 2- to 8-week survival period. The number of pUCM cells increased from approximately 5400 cells at the 2-week survival period post-transplantation to approximately 20,000 cells at the 8-week survival period. There was an increase in the percentage of TH-positive pUCM cells from approximately 1% at the 2-week survival period to approximately 6% at the 8-week survival period. There was no evidence of a significant host immune response at any time; for example, no accumulation of CD-4, CD-8, CD-11b, CD-161 cells in the transplantation site. These results suggest that pUCM cells engraft and proliferate without requiring immune suppression. These findings also suggest that a subset of pUCM cells can differentiate into TH-positive cells within 8 weeks after transplantation into the 6-OHDA lesioned rat brain.
A statistical analysis of 423 consecutive patients admitted to the Spinal Cord Injury Center, Rancho Los Amigos Hospital, 1 January 1964, through 31 December 1967.

A statistical analysis of 423 consecutive patients admitted to the Spinal Cord Injury Center, Rancho Los Amigos Hospital, 1 January 1964, through 31 December 1967