cssi/SciSciGPT-SciSciNet huggingface dataset:
A novel role for zebrafish zic2a during forebrain development

Patterns of transcription factor expression establish a blueprint for the vertebrate forebrain early in embryogenesis. In the future diencephalon, several genes with patterned expression have been identified, yet their specific functions and interactions between them are not well understood. We have uncovered a crucial role for one such gene, zic2a, during formation of the anterior diencephalon in zebrafish. We show that zic2a is required for transcription of the prethalamic markers arx and dlx2a. This function is required during early steps of prethalamic development, soon after its specification. zic genes are evolutionarily related to glis, transcription factors that mediate hedgehog signaling. Intriguingly, the hedgehog signaling pathway also acts to promote development of the prethalamus. We asked if zic2a interacts with hedgehog signaling in the context of forebrain development in zebrafish. Our data show that hedgehog signaling and zic2a function at different times, and therefore act in parallel pathways during forebrain development. Taken together, our results identify Zic2a as a novel regulator of prethalamic development, and show that it functions independently of hedgehog signaling.
K - -p and K - -n Cross Sections in the Momentum Range 1-4 Bev/c

The energy dependence of the ${K}^{\ensuremath{-}}$-nucleon total cross sections has been measured over the ${K}^{\ensuremath{-}}$ momentum range 0.98-3.98 Bev/c. ${K}^{\ensuremath{-}}\ensuremath{-}n$ cross sections were obtained by deuterium-hydrogen subtraction, with a correction for screening effects. There is evidence for structure in the $T=0$ ${K}^{\ensuremath{-}}$-nucleon state in the momentum range 0.98-2.0 Bev/c. This structure is absent in the $T=1$ state. In addition, a measurement was made at 1.95 Bev/c of the angular distribution of the ${K}^{\ensuremath{-}}\ensuremath{-}p$ elastic scattering at small angles. The forward-scattering amplitude obtained from the data gives a ratio of real part to imaginary part 0.5\ifmmode\pm\else\textpm\fi{}0.2 at ${0}^{0}$. The corresponding ratio for ${\ensuremath{\pi}}^{\ensuremath{-}}$ mesons at this momentum was found to be ${0.4}_{\ensuremath{-}0.4}^{+0.2}$.
Measurement of collateral blood flow in a porcine model of aortic coarctation by velocity-encoded cine MRI

The purpose of this study was to investigate the time course of development of collateral blood flow in an animal model of aortic coarctation. A juxtaductal aortic stenosis (model coarctation) was surgically created in five juvenile pigs. MRI was performed preoperatively, 1 to 2 days postoperatively, and 2 to 10 weeks postoperatively. Aortic blood flow was measured by velocity-encoded cine MR (VENC-MR). The percent change in aortic blood flow (delta BF) from proximal to distal descending thoracic aorta was calculated, and a multiple-comparison paired t test used to assess changes in delta BF over time. Invasive flow measurements were obtained in one animal before sacrifice using an ultrasonic probe. delta BF preoperatively was -2 +/- 8% (mean +/- SE). delta BF increased to 32 +/- 7% (mean +/- SE, P = .022) 2 days postoperatively and 55 +/- 19% (P = .032) 2 to 8 weeks postoperatively. Invasive measurements were in qualitative agreement with the VENC-MR data. VENC-MR is an accurate noninvasive method of measuring collateral blood flow in aortic coarctation. Recruitment and development of collateral flow pathways occur rapidly in an animal model.
The effect of the trimethylsilyl group on the regiochemistry of the ene reaction

Abstract The trimethylsilyl group has been found to have a profound effect on the regiochemistry of the ene reaction of E-1-methyl-2-trimethylsilyl olefins during the formation of [3.3.0] bicyclo-octanes.
Trispirocyclic Bis(dimethylaluminum)bis(amido)cyclodiphosph(V)azanes

The synthesis of the 2,4-bis(amino)cyclodiphosph(V)azane cis-[tBu(H)N(OPNtBu)2N(H)tBu] (3) and the syntheses and solid-state structures of cis-[Ph(H)N(EPNtBu)2N(H)Ph] (E = S (6), Se (7)) are reported. When 6 was treated with nBuLi, the dilithio salt {[(2THF·LiPhN)(SPNtBu)2(NPhLi·2THF)]·THF} (10) was isolated. The reactions of cis-[tBu(H)N(E=PNtBu)2N(H)tBu (E = O (3), S (4), Se (5)) and cis-[R(H)N(ArPNtBu)2N(H)R] (R = tBu, Ar = Ph (8), Ar = p-Tol (9)) with 2 equiv of trimethylaluminum afforded the bis(dimethylaluminum) complexes {(Me2Al)[RN(EPNtBu)2NR](AlMe2)} (R = tBu, E = O (11), E = S (12), E = Se (13); R = Ph, E = S (14), Se (15), and R = tBu, E = N-p-Tol (16), E = N−Ph (17)). Compounds 11, 12, and 16 were characterized by single-crystal X-ray studies and shown to be trispirocyclic complexes in which the ligands coordinate both dimethylaluminum moieties in an η2-fashion, as dimeric aminophosphoranates.
Structure and function of bacterial photosynthetic reaction centres

The primary reaction of photosynthesis is light-driven charge separation, carried out in reaction centres, which are complexes of integral membrane proteins and cofactors. The recent determination of the crystal structures of the reaction centres of two photosynthetic bacteria provides a basis for a quantitative understanding of the primary electron transfer processes of photosynthesis.
The effect of low-dose β-blockade on performance anxiety in singers

Summary Thirteen singing students received placebo or 20 mg of nadolol prior to their end-of-semester jury performance. The performance was repeated 48 h later with the cross-over drug regimen. Subjects' musical performances were evaluated by a panel of judges (comprised of the subjects' voice faculty). No statistically significant difference could be detected in the overall quality of the performance whether students were taking drug or placebo. Although the small number of subjects in this study precludes a definitive conclusion, these data, together with previous information, lead us to suggest that β-blockers are not useful in coping with nervousness in singing students.
Ultraviolet and Optical Studies of Binaries with Luminous Cool Primaries and Hot Companions. V. The Entire IUE Sample

We have obtained or retrieved IUE spectra for over 100 middle- and late-type giant and supergiant stars whose spectra indicate the presence of a hot component earlier than type F2. The hot companions are classified accurately by temperature class from their far-UV spectra. The interstellar extinction of each system and the relative luminosities of the components are derived from analysis of the UV and optical fluxes, using a grid of UV intrinsic colors for hot dwarfs. We find that there is fair agreement in general between current UV spectral classification and ground-based hot component types, in spite of the difficulties of assigning the latter. There are a few cases in which the cool component optical classifications disagree considerably with the temperature classes inferred from our analysis of UV and optical photometry. The extinction parameter agrees moderately well with other determinations of B-V color excess. Many systems are worthy of further study especially to establish their spectroscopic orbits. Further work is planned to estimate luminosities of the cool components from the data herein; in many cases, these luminosities' accuracies should be comparable to or exceed those of the Hipparcos parallaxes.
Water quality monitoring — Technological advantages and potential developments in the use of fibre optic technology

In this paper, a review of the primary drivers of the use of optical and fibre optic technology upon water quality monitoring is considered. The technological advances and challenges are discussed and the potential impact of new components, devices and methods illustrated for environmental monitoring into the future, using optical techniques.
Curriculum development resources for teachers and school librarians: a selection of resources

Purpose ‐ Curriculum development is a vital component in the educational process. Its scope is exceptionally broad, and it involves nearly everyone who is involved with teaching and learning, including teachers and librarians. Curriculum development resources offer guidance for lesson plan preparation that meets the educational standards set by each state. Resources for curriculum development for both teachers and librarians are abundant, with resources being offered both electronically and in print, freely available and for purchase. The purpose of this paper is to provide a selection of resources offered for teachers and those offered for librarians, electronically, in print, freely available, and for purchase. Design/methodology/approach ‐ Curriculum development resources were chosen based on the selection criteria included in the article, including: authority, accuracy, scope, appropriateness, and treatment. There were many resources for both teachers and librarians available, but only a few were selected. Those selected met the selection criteria and were outstanding and beneficial resources for curriculum development. Findings ‐ Resources for curriculum development for both teachers and librarians are abundant, with resources being offered both electronically and in print, freely available and for purchase. There are many resources for both teachers and librarians; however, teacher resources outnumber those for librarians. Perhaps in the upcoming years, as information literacy instruction becomes part of more institutions, further resources will be made available. Originality/value ‐ The function of curriculum development is to research, plan, and prepare the content and methods that will be taught during instruction to achieve the desired outcomes. State curriculum standards currently play a major role in schools and how the curriculum is developed. Curriculum development resources provide the necessary resources for teachers and librarians to plan and prepare curricula that can meet the standards set by each state.
PHOTOELECTRON IMAGING OF VIRUSES AND DNA : EVALUATION OF SUBSTRATES BY UNIDIRECTIONAL LOW ANGLE SHADOWING AND PHOTOEMISSION CURRENT MEASUREMENTS

Photoelectron imaging (photoelectron emission microscopy, PEM or PEEM) is a promising high resolution surface-sensitive technique for biophysical studies. At present, image quality is often limited by the underlying substrate. For photoelectron imaging, the substrate must be electrically conductive, low in electron emission, and relatively flat. A number of conductive substrate materials with relatively low electron emission were examined for surface roughness. Low angle, unidirectional shadowing of the specimens followed by photoelectron microscopy was found to be an effective way to test the quality of substrate surfaces. Optimal results were obtained by depositing approximately 0.1 nm of platinum-palladium (80:20) at an angle of 3 degrees. Among potential substrates for photoelectron imaging, silicon and evaporated chromium surfaces were found to be much smoother than evaporated magnesium fluoride, which initially appeared promising because of its very low electron emission. The best images were obtained with a chromium substrate coated with a thin layer of dextran derivatized with spermidine, which facilitated the spreading and adhesion of biomolecules to the surfaces. Making use of this substrate, improved photoelectron images are reported for tobacco mosaic virus particles and DNA-recA complexes.
Effects of Triiodothyronine (T3) Supplementation Upon Ozone-Induced Lung Injury

Ozone exposure results in an acute decrease in the serum levels of thyroid hormones; the physiologic sequelae of this are unclear. Whereas thyroid hormone supplementation appears to benefit pulmonary function in septic, oxyradical models of injury, thyroid hormone increases ozone toxicity. We demonstrated an increase in metabolic rate and pulmonary injury in lungs from ozone exposed, T3 treated animals. This was evidenced by an increase in pulmonary weight gain, vascular perfusion pressure, and decrease in compliance in the supplemented animals. However, an increase in alkane generation, as an index of lipid peroxidation, was not seen in the ozone exposed, hormonally treated animals. This suggests that although thyroid hormone supplementation increases metabolic rate and ozone toxicity, an increased rate of lipid peroxidation plays a minimal role.
Cancer metabolism meets systems biology: Pyruvate kinase isoform PKM2 is a metabolic master regulator

Pyruvate kinase activity is controlled by a tightly woven regulatory network. The oncofetal isoform of pyruvate kinase (PKM2) is a master regulator of cancer metabolism. PKM2 engages in parallel, feed-forward, positive and negative feedback control contributing to cancer progression. Besides its metabolic role, non-metabolic functions of PKM2 as protein kinase and transcriptional coactivator for c-MYC and hypoxia-inducible factor 1-alpha are essential for epidermal growth factor receptor activation-induced tumorigenesis. These biochemical activities are controlled by a shift in the oligomeric state of PKM2 that includes acetylation, oxidation, phosphorylation, prolyl hydroxylation and sumoylation. Metabolically active PKM2 tetramer is allosterically regulated and responds to nutritional and stress signals. Metabolically inactive PKM2 dimer is imported into the nucleus and can function as protein kinase stimulating transcription. A systems biology approach to PKM2 at the genome, transcriptome, proteome, metabolome and fluxome level reveals how differences in biomolecular structure translate into a global rewiring of cancer metabolism. Cancer systems biology takes us beyond the Warburg effect, opening unprecedented therapeutic opportunities.
Cross-validation of the economic significance of factors in security returns

Abstract Recently, researchers have indicated that factor analysis of security returns produces only a single statistically significant factor, but they did not investigate the economic significance of the derived factors. Using datasets constructed so as to minimize serial correlation, the cross-validation technique of Conway and Reinganum (1988) is extended to examine both the statistical and economic significance of extracted factors. This procedure also allows consideration of the reliability of the tests. Economic significance occurs more often than expected by chance for both the single statistically significant factor and for higher order factors, but the tests are highly inconsistent between original and holdout samples. The results imply that tests of the economic significance of individual estimated factors are unreliable and should be interpreted cautiously.
SiH and CH bond breaking during MeV-ion bombardment of a native oxide of silicon

Abstract We have studied the native oxide of silicon (110) and the changes produced by MeV-ion bombardment. The number of Si atoms incorporated in the oxide was measured using transmission channeling of 5.9 MeV 9 Be ions through a thin Si sample. Concentrations of adsorbed H, C and O were measured using ion scattering and elastic recoil detection analysis (ERDA) techniques. The native oxide was found to be composed of 1 2 monolayer each of Si and O, with several monolayers each of H and C. Continued 9 Be ion bombardment was found to increase the amount of Si in the oxide, up to a saturation value of one monolayer. The O concentration increased with dose, so that the ratio of Si to O in the oxide remained approximately one. An exponential decrease in the H concentration was observed, with the concentration approaching roughly one monolayer at large doses. A Si native oxide at the interface of a (thick) Si wafer and a 220 A Ag layer was studied using 58 MeV Cu ion bombardment at a glancing angle through the Ag layer. The concentrations of H, C and O were measured using ERDA. In this case, the H concentration also decreased exponentially with ion dose. These results will be discussed in terms of possible irradiation-induced chemistry in the native oxide.
Activation of somatostatin-synthesizing neurons in the hippocampal formation through kindling-induced seizures.

The present study was designed to determine if and to what extent somatostatin (SST) synthesizing neurons of the hippocampal formation are activated during seizures, elicited through kindling of the perforant pathway. Tissue was used and analyzed from animals which had experienced a single afterdischarge, or a stage 3 or stage 5 seizure. The protein expression of the oncogene c-fos in activated, depolarizing neurons was utilized to identify seizure-activated SST-synthesizing neurons. Combined immunocytochemical and in situ hybridization methods were used to identify these double-labeled, Fos protein, and SST mRNA-containing neurons. The results were quantified and compared across seizure stages. The resulting data demonstrate that at every stage of seizure development, a majority of SST-synthesizing neurons is activated, but that these activated SST mRNA-containing neurons represent only a minority of all seizure-activated, Fos-expressing neurons in the hippocampal formation. The data further reveal a numerical hierarchy in which the majority of double-labeled neurons is present in the hilus of the dentate, followed by the stratum oriens of CA1. It is concluded that SST-synthesizing neurons represent an integral component of the kindling activated neuronal network and, since the SST synthesizing neurons represent the minority of all seizure-activated neurons in the hippocampal formation, that this neuronal network is likely to be of considerable neurochemical complexity. & 1995 Wiley-Liss, Inc.
Progeny: sperm ratios and segregation-distorter in Drosophila melanogaster.

Progeny: sperm ratios (P/S) were determined from crosses ofSD/cn bw males ofDrosophila melanogaster with females of eight different genotypes. Thek value was about 1.0. P/S ratios of 0.88, 0.81, and 0.76, respectively, were observed from crosses with females of three genotypes, and ratios in the 0.3–0.4 range from five. These results support the suggestion ofZimmering & Fowler (1968) that P/S ratios may vary widely and depend at least in part on the genotype of the female. Morcover, since P/S ratios of 0.9 may be observed whenk is about 1.0, it follows that the vast majority of sperm stored in these females areSD.
Oviposition responses of gravid female Culex quinquefasciatus to egg rafts and low doses of oviposition pheromone under semifield conditions.

Semifield experiments were conducted to study the oviposition of gravid Culex quinquefasciatus females in response to one or 10 egg rafts, or 3.0 μg of synthetic oviposition pheromone, (-)-(5R,6S)-6-acetoxy-5-hexadecanolide, a dose equivalent to 10 egg rafts. These treatments were added to the small bowls filled with either hay infusion or water in a small (0.3-m spacing) or a large-square design (3.4-m spacing). Oviposition choice was more pronounced in the “small square” assays. Mean number of egg rafts laid in response to a single egg raft in an oviposition jar filled with hay infusion was significantly greater than with all other treatments. When the oviposition pheromone dose was increased from one to 10 rafts or when 3.0 μg synthetic oviposition pheromone were dispensed on a floating receptacle, synergistic effects were observed between the oviposition pheromone and the hay infusion at both distances. This study is the first demonstration that the amount in a single raft induces oviposition of gravid Cx. quinquefasciatus females under semi-natural conditions.
A bibliography of cost-effectiveness practices in physical medicine and rehabilitation: AAPM&R white paper.

Cost-effectiveness studies attempt to determine the ratio of costs to outcomes of a particular intervention or treatment and to compare a standard intervention with an alternative intervention to determine if the alternative is more cost effective. The goal is to establish priorities for the resources allocation and to decide among alternative interventions for the same medical condition. The global process of rehabilitation does not usually lend itself to cost-effective analysis (due to the complex set of treatments provided) but rather to specific interventions and specific aspects of outcome. The American Academy of Physical Medicine and Rehabilitation has published a cost effectiveness annotated bibliography on the Internet (http://www.aapmr.org/memphys/cebfinala.htm) that identifies 132 studies in the literature that meet specified criteria and are related to the field of rehabilitation. This White Paper attempts to interpret and synthesize the studies in that bibliography that relate to stroke, spinal cord injury (SCI), orthopedic conditions, pain syndromes, amputations, and traumatic brain injury (TBI). Most studies support the cost effectiveness of care for stroke and SCI in dedicated units or centers rather than in a general medical unit. Studies also support back programs and revascularization procedures in limb ischemia. Studies in TBI underscore the significant financial resources for the care of these patients as well as the potential benefit from rehabilitation services even in the most severely injured. Further high quality research in this area is needed.
Finite element stress analysis of thin die detachment process

One of the major developments in high-density electronic packaging assembly processes is the capability of handling very thin semiconductor devices. In order to achieve high production yield in the assembly processes and high reliability for the final packages, careful study on the handling method of very thin dice is therefore needed. In this article, we focus on the die detachment process of very thin dice in the die bonding process. Both 2D and 3D finite element models are built to simulate the die detachment process of a thin die, which is adhered to a plastic adhesive film. We report the stress distribution of the die when it is subjected to a displacement load by multiple push-up pins.
Leiomyoblastoma: behavior and prognosis.

Four cases of leiomyoblastoma are presented which illustrate the clinical presentations and gross anatomical appearance associated with this type of tumor when it is clinically significant. Case 1 is unique in having a markedly elevated mitotic rate with no evidence of metastasis at autopsy; it is the third case presenting as a pancreatic pseudocyst. Twenty-two cases of leiomyoblastoma reported in the literature since 1962 are reviewed. Experience with varying clinical presentations, gross anatomical and histologic appearances, and results of surgical therapy are summarized. Seven examples of metastasis of this tumor have been reported. In each case the rate of mitosis had significantly increased. Case 1 of our series had a mitotic rate from 2 to 3 times higher than those that metastasized, but no evidence of metastasis was present at autopsy. There may be variants of leiomyoblastomas with elevated mitotic rates that do not metastasize or do so only after a protracted course. Nevertheless, the mitotic rate remains die best criterion for prognosis.
Coronary Endothelial Dysfunction and Cerebrovascular Events

To the Editor: Targonski et al1 reported that coronary endothelial dysfunction (ED) in individuals without obstructive coronary artery disease (CAD) quadrupled the risk of cerebrovascular events, and these findings might offer insight into mechanisms of stroke and ischemic heart disease (IHD). ED fosters atherosclerosis,1 and Targonski et al1 focused on this effect of ED to explain ischemic stroke—a position consistent with the standard view that ischemic stroke and IHD are due directly to occlusions of conduit arteries by atherosclerotic complications as stenoses …
Axonal protein synthesis and the regulation of local mitochondrial function.

Axons and presynaptic nerve terminals of both invertebrate and mam- malian SCG neurons contain a heterogeneous population of nuclear-encoded mito- chondrial mRNAs and a local cytosolic protein synthetic system. Nearly one quarter of the total protein synthesized in these structural/functional domains of the neuron is destined for mitochondria. Acute inhibition of axonal protein synthesis markedly reduces the functional activity of mitochondria. The blockade of axonal protein into mitochondria had similar effects on the organelle's functional activity. In addition to mitochondrial mRNAs, SCG axons contain approximately 200 different micro- RNAs (miRs), short, noncoding RNA molecules involved in the posttranscriptional regulation of gene expression. One of these miRs (miR-338) targets cytochrome c oxidase IV (COXIV) mRNA. This nuclear-encoded mRNA codes for a protein that plays a key role in the assembly of the mitochondrial enzyme complex IV and oxidative phosphorylation. Over-expression of miR-338 in the axon markedly decreases COXIV expression, mitochondrial functional activity, and the uptake of neurotransmitter into the axon. Conversely, the inhibition of endogeneous miR-338 levels in the axon significantly increased mitochondrial activity and norepinephrine uptake into the axon. The silencing of COXIV expression in the axon using short, inhibitory RNAs (siRNAs) yielded similar results, a finding that indicated that the effects of miR-338 on mitochondrial activity and axon function were mediated, at least in part, through local COXIV mRNA translation. Taken together, recent findings establish that proteins requisite for mitochondrial activity are synthesized locally in the axon and nerve terminal, and call attention to the intimacy of the relationship that has evolved between the distant cellular domains of the neuron and its energy generating systems.
Biocatalytic Synthesis of β‐lactam Antibiotics

The penicillins, cephalosporins, carbapenems, and monobactams, make up the β-lactam family of antibiotics. There are currently more than 25 antibiotics in this family that are approved by the United States Food and Drug Administration and over 50 companies that manufacture them. Their four-membered β-lactam ring, which is the part of the antibiotic that is responsible for their bactericidal capabilities, is sensitive to acids, bases, and heat. Therefore, the original chemical synthesis processes utilized to make these compounds required subzero temperatures, hazardous chemicals for protecting groups, and large volumes of organic solvents, rendering them both environmentally harmful and economically taxing. The original syntheses are increasingly being replaced with biocatalytic syntheses which are carried out at ambient temperatures, in aqueous medium, and without the use of auxiliary chemicals, rendering them environmentally benign and economically advantageous processes. The most important enzymes utilized for these processes are penicillin G acylases, penicillin V acylases, cephalosporin acylases, and expandases. Keywords: β-lactam; enzymatic; industrial synthesis; penicillin G acylase
A Distributed and Parallel Component Architecture for Stream-Oriented Applications

This paper introduces ThreadMill – a distributed and parallel component architecture for applications that process large volumes of streamed (time-sequenced) data, such as is the case e.g. in speech and gesture recognition applications.
Use of tumor necrosis factor inhibitors in uveitis.

PURPOSE OF REVIEW: Use of tumor necrosis factor-alpha blocking agents to treat chronic pediatric uveitis is becoming recognized as an important therapeutic modality. This review summarizes the rationale for this use, highlighting new studies of these agents in pediatric uveitis. RECENT FINDINGS: The majority of patients with pediatric uveitis either have idiopathic uveitis or uveitis associated with juvenile idiopathic arthritis. Ophthalmologic morbidity among these children is common. Most studies evaluating tumor necrosis factor-alpha blockade in pediatric uveitis are retrospective case series, with attendant limitations that are inherent to any retrospective study. Study of uveitis has been hampered by lack of standardization of disease and outcome measures, which has been addressed by uveitis experts with publication of consensus measures. Data to date suggest that tumor necrosis factor-alpha blockade is efficacious in refractory uveitis. Agents with direct tumor necrosis factor-alpha membrane receptor binding activity may be the most efficacious. There remain many unanswered questions in the treatment of pediatric uveitis, including optimal dosing regimen and long-term efficacy. SUMMARY: Tumor necrosis factor-alpha blocking agents play an important role in the treatment of chronic pediatric uveitis. Prospective comparative studies are needed so that we may better understand this role.
Prediction of Absolute Rate Constants for the Reactions of NH2 with Alkanes from ab Initio G2M/TST Calculations

Systematic ab initio calculations of potential energy surfaces for the reactions of NH{sub 2} with various alkanes (CH{sub 4}, C{sub 2}H{sub 6}, C{sub 3}H{sub 8}, and i-C{sub 4}H{sub 10}) which involve abstraction of a hydrogen atom from primary, secondary, and tertiary C-H bonds have been performed using the G2M method. The calculated activation barrier for the NH{sub 2} + CH{sub 4} reaction, 15.2 kcal/mol, is higher than those for the H-abstraction from a primary C-H bond in C{sub 2}H{sub 6}, C{sub 3}H{sub 8}, and i-C{sub 4}H{sub 10}, 11--12 kcal/mol. The barrier height decreases to 8.4 and 8.3 kcal/mol for the abstraction from a secondary C-H bond in C{sub 3}H{sub 8} and a tertiary C-H bond in i-C{sub 4}H{sub 10}, respectively, in line with the weakening strength of the C-H bond and the increase of the reaction exothermicity. The G2M energies and the molecular and transition-state parameters are used to compute thermal reaction rate constants within the transition-state theory formalism with tunneling corrections. A good agreement of the theoretical rate constants with the experimental is found if the computed barriers are adjusted by 0.5--2 kcal/mol, which is within the accuracy of the G2M method. The H-abstraction from the tertiary C-H bondmore » is shown to be faster than the other considered reactions at T {le} 2000 K, while the secondary H-abstraction is the second fastest reaction at T {le} 1600 K. The rate of the primary H-abstraction decreases with the increase of the alkane size, from ethane to propane and to isobutane. The calculated rate constants for the H-abstraction by NH{sub 2} from primary, secondary, and tertiary C-H bonds can serve as models for the reactions of the amino radical with various saturated hydrocarbons.« less
Independent Component Analysis of Divergence Eye Movements

Vergence eye movements are the inward (convergence) or outward (divergence) turning of the eyes which allows humans to view objects in depth. Previous studies on the dynamics of convergence and divergence eye movements have produced varied, sometimes contradictory, results. Four subjects were studied and tracked four degree disparity step changes for convergence and divergence at different initial target positions. Here we report that the dynamics of divergence movements not only differ from convergence movement, but depend on the initial vergence position. Velocities of divergence eye movements in response to targets that were initially near to the subject were approximately twice that of responses to initially distant targets. Hence, while convergence responses are fairly similar irrespective of the initial position, divergence dynamic properties are dependent on the initial stimulus position. It is speculated that the differences observed in divergence may be the result of a difference in the underlying neural controller potentially a difference in the magnitude of the fusion initiating component. Preliminary data using independent component analysis (ICA) shows the divergence system contains a step and pulse where the amplitude of the pulse is dependent on the initial stimulus position
Enrichment of a Precore-Minus Mutant of Duck Hepatitis B Virus in Experimental Mixed Infections

A precore-deficient mutant of duck hepatitis B virus (DHBV) produced by site-directed mutagenesis was tested for its ability to compete with wild-type virus in a mixed infection of 3-day-old ducklings. The mutation was shown to produce a cis-acting defect, resulting in a replication rate that was about one-half that of wild-type virus. Accordingly, wild-type virus was rapidly selected during the spread of infection. During the chronic phase of the infection, however, two selection patterns were seen. In 4 of 10 ducks, the wild-type virus slowly replaced the precore mutant. In another four ducks, the precore mutant virus slowly replaced the wild-type virus. In the remaining two ducklings, ratios of wild-type and precore mutant virus fluctuated, with wild-type virus slowly predominating. The replacement of wild-type virus was not due to the emergence of a rapidly replicating variant of the precore mutant, since genomes cloned from the infected ducks retained their original replication defect. Replacement of wild-type virus, however, correlated with elevated anti-core antibody titers, which continued to increase with time. The selection of a precore-negative strain of DHBV may be analogous to the selection for precore mutants of HBV during chronic hepatitis in humans.
A performance validation tool for J2EE applications

J2EE is the de-facto industry standard for implementing and scaling Java on the enterprise scale distributed systems. It is the result of strong industry collaboration. All involved is trying to make the technology J2EE commercially viable. This industry support has allowed J2EE to be based on the experience and expertise from leading designers of industry systems that are scalable, well integrated and provided a cross platform environment for application development, deployment and management. One of the major problems in building large-scale enterprise systems is managing the performance of the eventual solution. It is also true for J2EE based systems. This paper proposes an approach for accurate analysis of J2EE applications. It discusses the design of JPManager - a J2EE performance management system and related techniques, such as Java instrumentation, which is used in the JPManager's implementation.
Comparison of Methods of DNA Extraction from Stream Sediments

In Upper Three Runs Creek (Aiken, S.C.) and many other environments, less than 1% of bacteria visible microscopically can be cultured. Exploitation of molecular biology techniques has led to development of new methods, such as extraction of nucleic acids from soils or sediments, to study the dominant, nonculturable bacteria. The purpose of this study was to compare three published methods of DNA extraction that fall into two general categories: those in which cells are lysed in sediments (the Ogram and Tsai and methods [A. Ogram, G. S. Sayler, and T. Barkay, J. Microbiol. Methods 7:57-66, 1987; Y. L. Tsai and B. H. Olson, Appl. Environ. Microbiol. 57:1070-1074, 1991]) and those in which cells are removed from sediments prior to lysis (the Jacobsen method [C. S. Jacobsen and O. S. Rasmussen; Appl. Environ. Microbiol. 58:2458-2462, 1992]). DNA yield varied with extraction method; the Ogram method had a significantly higher yield than the other methods. However, DNA extracted via the Ogram method was badly sheared and contained a smaller proportion of eubacterial DNA. The Tsai method was less time consuming than the other methods, but DNA samples were of lower purity. If DNA purity is of paramount concern (as would be the case if PCR was to be performed) and quantity is not important, the Jacobsen method is recommended because of the low concentration of contaminants. If DNA is to be used directly in DNA-DNA hybridizations, the Ogram method is recommended since it gives maximal yields.(ABSTRACT TRUNCATED AT 250 WORDS)
Interactions of phenytoin with rat brain synaptosomes examined by fluorescent fatty acid probes.

Abstract Phenytoin (PHT) modified the fluorescent characteristics of anthroyloxy-fatty acids in synaptosomal membranes. Association of PHT with synaptosomal membranes caused the greatest change when the fluorescent probe was located at the 6-carbon position of N -(anthroyloxy)stearic acid and was incorporated into the membranes. Phenytoin and 6-(anthroyloxy)stearic acid compete for high affinity binding regions which are probably lipid domains within the membrane. Phenytoin has a weaker association with the sites than the fluorescent fatty acids. Divalent cations, e.g. Mg 2+ or Ca 2+ , are required to observe maximal change in polarization of fluorescence of fatty acid probes in the presence of PHT. It is proposed that the membrane lipid bilayer reorganizes to accommodate exogenous compounds, such as phenytoin or the fatty acid probe in order to permit the most efficient packing of lipids. This reorganization of the lipid bilayer may influence membrane enzyme activities and ion channels.
Atherosclerosis Regression, Plaque Disruption, and Cardiovascular Events: A Rationale for Lipid Lowering in Coronary Artery Disease

In the Familial Atherosclerosis Treatment Study (FATS), the reduction in clinical events (75%) far outweighed the modest frequency and magnitude oflesion regression observed among those receiving intensive lipid-lower­ ing therapy. To understand this result, the disruptive changes in plaque that trigger clinical events (cardiac death, myocardial infarction, unstable angina) are described. Data are presented in support of the idea that the clinical benefits of lipid-lowering therapy are best explained by stabil­ ization, by depletion of lipid, of the "dangerous" subpopulation of lipid­ rich plaques that are often associated with only mild or moderate coronar y narrowing.
Comparisons and analysis of massively parallel SIMD architectures for parallel logic simulation

This paper compares and analyzes massively parallel SIMD architectures as processing environments for parallel logic simulation. The CM-2 and the MP-1 are considered as target machines for the comparison. Detailed contrasts between the two parallel schemes are made based on actual simulation results and system performance. Distributed event-driven simulation protocols are used to obtain experimental results for the two massively SIMD machines. According to the results, the MP-1 is 2 to 2.5 times faster than the CM-2 for up to 16 K gate benchmark circuits, while the CM-2 can accommodate circuits with a larger number of gates of processors. The presented comparisons and analysis of the two machines can be used to choose a SIMD machine for efficient parallel logic simulation.
Effects of a product display and environmental fragrancing on approach responses and pleasurable experiences

The effects of atmospherics (i.e., a product display, pleasant and [in] appropriate ambient fragrances) on approach responses toward a product (global attitude, purchase intention, estimated price, and price the customer is willing to pay) and pleasurable experiences (sensory, affective, and cognitive pleasure) were investigated. In addition, the mediating effects of sensory, affective, and cognitive pleasure on approach responses toward a product were examined. Statistical analysis of responses of 109 female subjects each randomly assigned to one of four treatments showed that the appropriately fragranced display generated the most positive effect on approach responses and pleasurable experiences. A component of cognitive pleasure (seeing oneself in a fantasy) and multisensory pleasure mediated two approach responses: attitude toward the product and purchase intention. Findings suggest the importance of combining a display with environmental fragrancing as a marketing tool, but careful selection and application of environmental fragrances are required. © 2000 John Wiley & Sons, Inc.
Availability estimation of routes, trees and subnetworks for end-to-end QoS

We present a method that offers a simple way of estimating the availability of routes, trees or other subnetworks with dependent links. Such dependencies typically exist in ad hoc networks, where the evaluation of global availability is important for ensuring end-to-end quality of service. The method is presented in a general form, so that it can also be applied to many other scenarios.
Evaluation of Breast Silicone Implants

While clinical evaluation of breast implants and their complications can identify capsule contracture and rupture of saline implants, the identification of silicone implant failure is best accomplished by silicone specific protocols for MRI with orthogonal acquisition. Such imaging can also help resolve other clinical problems. Following a brief overview of the history and development of commercial use of silicone implants and alternatives, this article outlines the approach toward optimal imaging and expected results.
A comparison of normal estimation schemes

The task of reconstructing the derivative of a discrete function is essential for its shading and rendering as well as being widely used in image processing and analysis. We survey the possible methods for normal estimation in volume rendering and divide them into two classes based on the delivered numerical accuracy. The three members of the first class determine the normal in two steps by employing both interpolation and derivative filters. Among these is a new method which has never been realized. The members of the first class are all equally accurate. The second class has only one member and employs a continuous derivative filter obtained through the analytic derivation of an interpolation filter. We use the new method to analytically compare the accuracy of the first class with that of the second. As a result of our analysis we show that even inexpensive schemes can in fact be more accurate than high order methods. We describe the theoretical computational cost of applying the schemes in a volume rendering application and provide guidelines for helping one choose a scheme for estimating derivatives. In particular we find that the new method can be very inexpensive and can compete with the normal estimations which pre-shade and pre-classify the volume (M. Levoy, 1988).
Diet and Breast Cancer: Studies in Laboratory Animals

Increasing dietary fat content increases mammary gland tumorigenesis in laboratory rodents. The effect can be attributed only in part to increasing energy intake, which itself increases tumorigenesis. Restriction of dietary or energy intake, sufficient to reduce body weight, reduces mammary gland tumorigenesis. Consideration of these effects has led to discussion of the possible need for changes in the feeding of laboratory rodents in carcinogenesis bioassays and other chronic studies. Studies of endocrine or other growth factors for the mammary gland have not identified specific effects of dietary fat or energy. In addition, tumorigenesis in other organs responds similarly to increased fat or decreased energy intake, indicating that the mechanisms are not, or not entirely, specific for the mammary gland. Extrapolations of results between species must always be made with caution, but the marked effects of dietary fat and energy in rodent tumorigenesis models must be considered in designing diet advice for humans.
Individualism, Communitarianism and Consensus

There is a contemporary conflict between individualistic andcommunitarian conceptions of rationality. Robert Goodin describes it asa conflict between an enlightenment individualistic conception of a``sovereign artificer'' and ``a socially unencumbered self'' ascontrasted with the communitarian conception of a ``socially embeddedself'' whose identity is formed by his or her community. Should wejustify and explain rationality individualistically or socially? This isa false dilemma when consensus is reached by a model articulated byKeith Lehrer and Carl Wagner. According to this model, the consensusresults from the positive weights individuals give to others and use tocontinually average and, thus, aggregate their allocations. Aggregationconverges toward a consensus in which the social preference and theindividual preferences become identical. The truth of communitarianismis to be found in the aggregate and the truth of individualism in theaggregation. The original conflict dissolves in rational consensus.
Effects of salinity on physiological parameters of grafted and ungrafted citrus trees

Abstract Subtropical and tropical climates are becoming more vulnerable to drought and salinity problems. Of the crops produced in these climates, citrus is especially sensitive to increasing salinity. In times of water scarcity and periodic drought alternative water sources that may be lower in quality may be required for irrigation, leading to reduced yield unless a mechanism of increasing salinity tolerance is found. The salinity tolerance of citrus rootstocks differs depending on species and cultivar in their ability to exclude or sequester toxic ions. Identifying rootstocks that are more salt tolerant is important to citrus production in susceptible areas. ‘Olinda’ Valencia trees budded to three rootstocks (sour orange [SO], C22, and C146) and the ungrafted rootstocks were subjected to 6 months of saline irrigation. Simulated brackish water at 1, 3, 5, and 10 dS m −1 along with a 0 dS m −1 control were used to irrigate trees over the course of the study. Throughout this time period chlorophyll fluorescence, stomatal conductance, electrolyte leakage, and SPAD were measured to identify how trees responded to different levels of salinity stress. Chlorophyll fluorescence, stomatal control, and SPAD decreased with increased salinity, while electrolyte leakage increased. These responses were more pronounced in grafted trees than ungrafted trees. C22 and C146 rootstocks showed more tolerance to increases in salinity than the SO rootstocks. The ‘Olinda’ Valencia scion reduces rootstock tolerance to salinity, however, trees grafted to the C22 and C146 rootstocks showed more salinity tolerance than those grafted to SO rootstocks. This study emphasizes that both rootstock and scion should be considered when selecting trees for saline conditions.
EVIDENCE OF DIFFERENTIAL MIGRATION BY SEX IN WHITE-THROATED SPARROWS (ZONOTRICHIA ALBICOLLIS)

Abstract Differential migrants are species in which one population class migrates farther than another. White-throated sparrows (Zonotrichia albicollis), which migrate into the southern United States each autumn in large numbers, have been proposed as a candidate differential migrant (Cristol et al. 1999). Using Bird Banding Lab data, we tested for latitudinal variation in the sex ratio of White-throated Sparrows in the Atlantic and central flyways. We found that the proportion of females increases with decreasing latitude in at least the Atlantic flyway, strongly suggesting that females migrate farther than males. Sex ratios calculated from those banding data were compared to those of museum specimens collected at the same latitudes, as well as single-season population samples at three latitudes in the heart of the winter range. Broad agreement was found using the three independent methods of sampling the sex ratio, so we conclude that White-throated Sparrows are differential migrants.
Alterations in Muscle and Retinal Cell Structure after Exposure to Light

Exposure of albino rats to both incandescent and fluorescent low-level radiant energy causes damage and degeneration to the photoreceptor cells and pigment epithelial cells of the retina and to the muscle fibers of the extraocular muscles (1–4). The type of cellular damage is the same for both incandescent and for fluorescent light exposed animals (5). Our previous studies indicate that elevated environmental and orbital temperatures are not responsible for the damage seen in the retina or in the myofibers of the extraocular muscles. In order to better understand the relation between light exposure and damage in such diverse cell types, the sequences of ultrastructural changes has been examined.