cssi/SciSciGPT-SciSciNet huggingface dataset:
Interaction between chemical reaction and turbulence in supersonic nonpremixed H2-air combustion

A numerical model for supersonic turbulent nonpremixed hydrogen-air jet flames is developed for exploring the interaction between chemical reaction and turbulence. The numerical code employs an implicit finite-volume, lower-upper successive overrelaxation (LU-SSOR) scheme for solving density-averaged Navier-Stokes equations with chemical reactions in axisymmetric flows. The effects of turbulence on chemical reaction are included by approximations appropriate in the limit of weak turbulence. Comparison of numerical results with and without the influence of turbulence on the chemical kinetics reveals that even under the condition of weak turbulence, the effect of turbulence on chemistry can be significant.
Preparation of ginkgolide and F-seco-ginkgolide lactols: the unique reactivity of α-hydroxy lactones toward NaBH4

Abstract It has been found that NaBH 4 smoothly reduces the α-hydroxy-lactone moieties in ginkgolide and F-seco-ginkgolides to lactols. The reaction is rapid and stops at the lactol stage; the coordination of NaBH 4 to the conformationally rigid cage structure is involved in both the initiation and termination stages. This facile reduction of ginkgolide lactones yields a variety of new ginkgolide lactols.
Salt Effects on an Ion–Molecule Reaction—Hydroxide-Catalyzed Hydrolysis of Benzocaine

This work investigates the effect of various salts on the rate of a reaction involving a neutral species (benzocaine alkaline hydrolysis). Benzocaine hydrolysis kinetics in NaOH solutions in the presence of different salts were studied at 25°C. Benzocaine solubility in salt solutions was also determined. Solubility data were used to estimate salt effects on benzocaine activity coefficients, and pH was used to estimate salt effects on hydroxide activity coefficients. Salts either increased or decreased benzocaine solubility. For example, solubility increased with 1.0 M tetraethylammonium chloride (TEAC) ∼3-fold, whereas solubility decreased ∼35% with 0.33 M Na2SO4. Salt effects on hydrolysis rates were more complex and depended on the relative magnitudes of the salt effects on the activity coefficients of benzocaine, hydroxide ion, and the transition state. As a result, some salts increased the hydrolysis rate constant, whereas others decreased it. For example, the pseudo-first-order rate constant decreased ∼45% (to 0.0584 h−1) with 1 M TEAC, whereas it increased ∼8% (to 0.116 h−1) with 0.33 M Na2SO4. Different salt effects on degradation kinetics can be demonstrated for a neutral compound reacting with an ion. These salt effects depend on varying effects on activity coefficients of reacting and intermediate species.
SiO 2 as barrier layer for Na out-diffusion from soda-lime glass

To reduce the manufacturing cost, soda-lime glass (SLG) is often used as the substrate for thin-film solar cells. It is known that SLG contains about 16 wt% Na in the form of Na 2 O. During the growth of thin films, Na ions may diffuse out from SLG and diffuse into the grown thin films and affect the optoelectronic properties of the thin films. The widely used commercial F-doped Sn 2 O (FTO) glass (Teck 15) has the structure SLG/FTO/SiO 2 /FTO. The first FTO layer and the SiO 2 layer are very thin. The SiO 2 layer is often expected to be a barrier layer for Na out-diffusion from SLG. However, our transmission electron microscopy (TEM) study indicates that there is a significant amount of Na existing in the second FTO layer, further indicating that SiO 2 may not be a good barrier layer for Na out-diffusion. Therefore, we have investigated the possibility of a SiO 2 layer as a barrier layer for Na out-diffusion from SLG. We have deposited two types of samples, SLG/SiO 2 /FTO and SLG/FTO, at 550°C. For comparison, these samples were also annealed at temperatures between 550° and 650°C. The as-deposited and annealed samples were examined by TEM, X-ray energy dispersive spectroscopy (EDS) and secondary-ion mass spectrometry (SIMS). We found that SiO 2 is indeed an effective barrier layer for Na out-diffusion. Thermal annealing can enhance Na diffusion. It should be pointed out that our deposited SiO 2 layer may behave differently from the SiO 2 layer seen in the commercial FTO-coated glass.
The Temporal Nature of Racialized Sport Consumption

An interdisciplinary body of sport research contends that mediated portrayals of athletic conduct are contingent upon the race/ethnic identity of a respective athlete. While prior research has considered how such racialized dynamics become organized, this study extends the research by considering the degree to which temporal dynamics contribute to the consumption of racialized sport. Content analysis of 2,367 lines of commentary talk, enacted among sport commentators in the 2000 Men’s and Women’s NCAA Final Four Tournament games, revealed how temporal patterns differentially gave rise to the consumption of racialized sport. The findings extend our understanding of (a) the commodification of athletic identities in mediated talk and (b) the prospect of aversive racism in the domain of mediated sport.
Picosecond investigations of optical limiting mechanisms in King's complex

We have investigated the nonlinear optical mechanisms responsible for optical limiting of both picosecond and nanosecond 532-nm optical pulses in the organometallic compound cyclopentadienyliron carbonyl tetramer (King's complex). For fluences below ~200 mJ/cm 2 , picosecond pump-probe measurements in solutions of the King's complex reveal a prompt reverse saturable absorption (RSA) that recovers with a time constant of 120 ps. We attribute this RSA to excited-state absorption within the singlet system of the King's complex, and we demonstrate that the RSA is completely characterized by a simple three-level model. We find, however, that the material parameters extracted from these picosecond measurements cannot account for the strong optical limiting previously observed in identical solutions of this compound using nanosecond excitation at higher fluences. Picosecond measurements at fluences greater than 200 mJ/cm 2 reveal the onset of an additional loss mechanism that appears ~1 ns after excitation. The magnitude of this loss depends on both the laser repetition rate and the solvent, indicating that the loss is not directly related to the intrinsic properties of the King's complex but is most likely thermal in origin. Using nanosecond excitation pulses, we have performed angularly resolved transmission and reflection measurements, which reveal strong forward- and backward-induced scattering at these fluences. Furthermore, when the King's complex is incorporated in a solid host, we observe negligible induced scatter and the response is completely described by the singlet parameters extracted from the picosecond measurements. These observations indicate that the nanosecond optical limiter response of solutions of King's complex is dominated by thermally induced scattering.
Characterization of HgCdTe Epilayers and HgTe-CdTe Superlattice Structures Grown by Molecular Beam Epitaxy

The results of an in-depth study of HgCdTe epilayers and HgTe-CdTe superlattice structures are summarized. In particular, both spectral and transient photoconductance measurements have been made on samples which were also characterized by x-ray diffraction, Hall, IR transmission, IR photoluminescence, and transmission electron microscopy measurements. Selected HgCdTe samples grown at General Electric during this investigation exhibit some of the best structural and electrical properties reported to date for MBE-grown HgCdTe. Sharp photoconductance spectra have been obtained for HgTe-CdTe superlattice structures grown at North Carolina State University. This study is part of an on-going collaborative effort between General Electric’s Electronics Laboratory and North Carolina State University.
New cosmological models in the five-dimensional space-time-mass gravity theory

A new class of vacuum solutions in the new five-dimensional space-timemass gravity theory is found. These new cosmological models describe expanding universes without a big bang singularity, and the fifth dimension of these models shrinks as they expand.
Quantitative modeling of a gene's expression from its intergenic sequence.

Modeling a gene's expression from its intergenic locus and trans-regulatory context is a fundamental goal in computational biology. Owing to the distributed nature of cis-regulatory information and the poorly understood mechanisms that integrate such information, gene locus modeling is a more challenging task than modeling individual enhancers. Here we report the first quantitative model of a gene's expression pattern as a function of its locus. We model the expression readout of a locus in two tiers: 1) combinatorial regulation by transcription factors bound to each enhancer is predicted by a thermodynamics-based model and 2) independent contributions from multiple enhancers are linearly combined to fit the gene expression pattern. The model does not require any prior knowledge about enhancers contributing toward a gene's expression. We demonstrate that the model captures the complex multi-domain expression patterns of anterior-posterior patterning genes in the early Drosophila embryo. Altogether, we model the expression patterns of 27 genes; these include several gap genes, pair-rule genes, and anterior, posterior, trunk, and terminal genes. We find that the model-selected enhancers for each gene overlap strongly with its experimentally characterized enhancers. Our findings also suggest the presence of sequence-segments in the locus that would contribute ectopic expression patterns and hence were “shut down” by the model. We applied our model to identify the transcription factors responsible for forming the stripe boundaries of the studied genes. The resulting network of regulatory interactions exhibits a high level of agreement with known regulatory influences on the target genes. Finally, we analyzed whether and why our assumption of enhancer independence was necessary for the genes we studied. We found a deterioration of expression when binding sites in one enhancer were allowed to influence the readout of another enhancer. Thus, interference between enhancer activities was a possible factor necessitating enhancer independence in our model.
No free lunch: displaced marsh consumers regulate a prey subsidy to an estuarine consumer

Pulse subsidies account for a substantial proportion of resource availability in many systems, having persistent and cascading effects on consumer population dynamics, and energy flow within and across ecosystem boundaries. Although the importance of pulsed resource subsidies is well-established, the mechanisms that regulate resource fluxes across ecosystem boundaries are not well understood. The aim of our study was to determine the extent that marsh consumers regulated a marsh prey subsidy to estuarine consumers in the oligohaline reaches of an Everglades estuary. We characterized a marsh pulsed subsidy of cyprinodontoid, invertebrate and sunfish prey that move into the upper estuary from adjacent drying marshes. In response to the prey pulse, we examined the numerical, fitness and dietary responses of three focal consumers in the upper estuary; two marsh species (largemouth bass and bowfin) that accompanied the subsidy as a result of marsh drying, and one estuarine consumer (snook). At the onset of marsh drying and the prey subsidy, estuarine consumers switched diets to consume the larger marsh prey (sunfishes), while bass and bowfin maintained similar diets (cyprinodontoids and invertebrates respectively) than pre and post subsidy. From the consumption of this subsidy, bass (marsh species) and snook (estuarine species) exhibited fitness gains while bowfin did not. Although both marsh and estuarine consumers benefitted from the subsidy, we found evidence that freshwater consumers shunted some of the subsidy away from snook. Of the prey sampled in consumer stomachs, 41% of marsh prey biomass was eaten by marsh consumers, while 59% was consumed by the estuarine consumer. We conclude that the amount of the marsh prey available to estuarine consumers may be greater in the absence of marsh consumers, thus the magnitude of the prey subsidy could depend on the dynamics of the marsh consumers from donor communities.
Testing the efficiency of plant artificial microRNAs by transient expression in Nicotiana benthamiana reveals additional action at the translational level

Artificial microRNAs (amiRNAs) have become an important tool to assess gene functions due to their high efficiency and specificity to decrease target gene expression. Based on the observed degree of complementarity between microRNAs (miRNAs) and their targets, it was widely accepted that plant miRNAs act at the mRNA stability level, while the animal miRNAs act at the translational level. Contrary to these canonical dogmas, recent evidence suggests that both plant and animal miRNAs act at both levels. Nevertheless, it is still impossible to predict the effect of an artificial miRNA on the stability or translation of the target mRNA in plants. Consequently, identifying and discarding inefficient amiRNAs prior to stable plant transformation would help getting suppressed mutants faster and at reduced cost. We designed and tested a method using transient expression of amiRNAs and the corresponding target genes in Nicotiana benthamiana leaves to test the efficacy of amiRNAs for suppression of the target protein accumulation. The ability of the amiRNAs to suppress the target gene expression in N. benthamiana was then compared to that in stably transformed Arabidopsis. It was found that the efficacy of sixteen amiRNAs, targeting a total of four genes, varied greatly. The effects of amiRNAs on target mRNAs accumulation did not always correlate with target protein accumulation or the corresponding phenotypes, while a similar trend of the silencing efficacy of amiRNAs determined between N. benthamiana and stably transformed Arabidopsis could be observed. Our results showed that, similar to endogenous plant miRNAs, plant amiRNAs could act at the translational level, a property needed to be taken into account when testing the efficacy of individual amiRNAs. Preliminary tests in N. benthamiana can help determine which amiRNA would be the most likely to suppress target gene expression in stably transformed plants.
A unique sensor histidine kinase.

Sporulation initiation in Bacillus species is controlled by an extended version of two-component signal transduction systems, termed phosphorelay ([4][1]). The cascade of His→Asp→His→Asp phosphotransfer is typically initiated by the ATP-dependent autophosphorylation of the histidine kinase
Viridans streptococcal bacteremia after esophageal stricture dilation

Background: The incidence of bacteremia with organisms that may cause infective endocarditis after esophageal stricture dilation is unknown. There is disagreement among physicians regarding the need for antibiotic prophylaxis for patients with valvular heart disease undergoing dilation. Our aim was to determine the frequency and duration of bacteremia associated with esophageal stricture dilation. Methods: Blood cultures were obtained before and after stricture dilation in patients without valvular heart disease and in a control group of patients undergoing upper endoscopy without dilation. Results: A total of 103 patients undergoing dilation and 50 control patients were studied; 22 of 103 patients (21%) undergoing dilation had at least one post-procedure blood culture positive for viridans streptococcus, compared with 1 of 50 (2%) of control patients (p = 0.001). Blood cultures obtained 1 minute after stricture dilation were positive for viridans streptococcus in 19 of 81 (23%), in 16 of 96 (17%) 5 minutes post-dilation, and in 3 of 63 (5%) 20 to 30 minutes post-dilation. Of the 19 patients with viridans streptococcus bacteremia 1 minute after dilation, cultures were still positive in 14 of 19 (74%) at 5 minutes and in 2 of 19 (10%) 20 to 30 minutes post-dilation. Conclusions: These data support the use of antibiotic prophylaxis before esophageal stricture dilation for patients with valvular heart disease at risk for the development of infective endocarditis. (Gastrointest Endosc 1998;48:568-73.)
Picosecond Dynamics of Intermolecular Proton and Deuteron Transfer between Benzophenone and N,N-Dimethylaniline

Picosecond absorption spectroscopy is used to study the dynamics of proton and deuteron transfer in the benzophenone/N,N-dimethylaniline contact radical ion pair in the solvents benzene and tetrahydrofuran. From temperature-dependent studies of this kinetic process, the energy of activation and A factors for proton and deuteron transfer are derived. These parameters are then analyzed within the classical and semiclassical models for proton transfer, the Borgis−Hynes model for proton transfer, and the two-step model developed by Kreevoy and Kotchevar for hydride transfer. We conclude that prior to proton transfer there is a rate-limiting reorganization of the contact radical ion pair complex that allows for the transfer of the proton.
Sustainability Assessment of Industrial Systems

Sustainability is a vital issue for long-term development of industries and effective environmental protection. The principal aim of sustainable development is the progress on all fronts, i.e., economy, environment, and society. In this paper, a set of new sustainability indices is introduced to assess the environmental and economic performances as well as the sustainability of industrial systems in a uniform structure. In these indices, the values of nonmoneyed and moneyed resources, services, and commodities are quantified using a common unit: emergy. As compared to the existing emergy-based sustainability indices that originated from the study on agricultural or natural ecological systems, the newly defined indices improve the applicability and the effectiveness of the existing indices by addressing the unique features of industrial systems systematically. These new indices reveal strong interdependence among multiple objectives and provide clear guidance to the industries on how to improve their performance on multiple fronts. The utilities of the new indices are demonstrated by case studies.
Temporal patterns of reported single-vehicle car and truck accidents in Texas, U.S.A. during 1980-1983.

Reported single car and truck accidents due specifically to driver 'fatigue' for the 4-year span of 1980-1983 were analyzed for 24-hr, 7-d and 1-yr patterns. Three types of data were examined: (1) accidents in rural Texas, (2) accidents only in San Antonio, the fourth largest city in Texas and (3) accident ratio (number of accidents per time interval divided by traffic volume for the interval) in this city.A statistically significant seasonal variation of relatively low amplitude with peaks in May and July was detected only for accidents in rural areas. High-amplitude periodicities of 7 d were evident in all the data sets, with a peak on the weekend. A very prominent 24-hr pattern was detected as well, with the acrophase determined by single cosinor around 0300. A slight secondary peak in accidents, around 1500, was evident in the data from the rural areas. This secondary peak represented a 12-hr rhythm in addition to the 24-hr. Overall, features of the temporal patterns in accidents over 24 hr and over t...
Progress of liquid chromatography-mass spectrometry in measurement of vitamin D metabolites and analogues.

Abstract Objective Clinical testing for vitamin D nutritional status has experienced tremendous growth in the past several years, driven by research results linking various diseases with low serum 25-hydroxyvitamin D [25(OH)D] levels. Meanwhile, interest in the pathophysiological mechanism elucidation and pharmaceutical applications requires measurement of vitamin D metabolites and analogues. Liquid chromatography-mass spectrometry (LC-MS) has been increasingly utilized in these applications. In this work, our objective was to critically review the progress of LC-MS application in measuring vitamin D metabolites and analogues in biological fluids. Methods The LC-MS methods included were selected from those searchable in PubMed up to January 2010. Results and Conclusion LC-MS has unique advantages in measuring various vitamin D metabolites and analogues due to its flexibility, sensitivity, and specificity. Despite some controversies over serum 25(OH)D tests, LC-MS will be used for standardizing serum 25(OH)D assays using reference materials available from the National Institute of Standards and Technology.
Radiographic analysis of zebrafish skeletal defects

Systematic identification of skeletal dysplasias in model vertebrates provides insight into the pathogenesis of human skeletal disorders and can aid in the identification of orthologous human genes. We are undertaking a mutagenesis screen for skeletal dysplasias in adult zebrafish, using radiography to detect abnormalities in skeletal anatomy and bone morphology. We have isolated chihuahua, a dominant mutation causing a general defect in bone growth. Heterozygous chihuahua fish have phenotypic similarities to human osteogenesis imperfecta, a skeletal dysplasia caused by mutations in the type I collagen genes. Mapping and molecular characterization of the chihuahua mutation indicates that the defect resides in the gene encoding the collagen I(α1) chain. Thus, chihuahua accurately models osteogenesis imperfecta at the biologic and molecular levels, and will prove an important resource for studies on the disease pathophysiology. Radiography is a practical screening tool to detect subtle skeletal abnormalities in the adult zebrafish. The identification of chihuahua demonstrates that mutant phenotypes analogous to human skeletal dysplasias will be discovered.
The photophysics of the 2,6 dialkoxy anthracenes: Evidence for excited state side-chain conformational relaxation

Abstract Three 2,6 dialkoxyanthracenes with varying ether sidechain lengths (methyl, n -propyl and n -hexyl) are synthesized and characterized. When compared to unsubstituted anthracene, the spectroscopic properties of the alkoxy-anthracenes are significantly different. The oscillator strength appears to be evenly distributed between the L a and L b states, rather than concentrated in the low-energy L a state, and the transition dipole moments are rotated by ∼30° in the molecular frame. More importantly, all three derivatives undergo an intramolecular conformational change in the excited state that gives rise to a reshaping of the fluorescence spectrum on the nanosecond timescale. This process has an activation energy of 8±1 kJ/mol. By ∼150 K the fluorescence spectrum reflects only the high energy conformer, whose emission lineshape is similar to that of the unsubstituted anthracene. The temperature-dependent changes in the monomeric fluorescence spectra of these compounds will have to be taken into account in future studies of their solid-state spectroscopy.
Irregular recycling of demand pacemakers from borderline electrographic signals

Abstract In most clinical situations the sensing mechanism of demand (ventricular-inhibited) pacemakers responds to incoming signals in an all-or-none fashion with respect to its recycling property. However, electrographic signals of threshold amplitude for sensing may cause partial suppression (irregular recycling) of certain normally functioning demand pacemakers and produce a complex arrhythmia, designated as partial sensing and characterized by irregularly shortened escape intervals. Partial sensing disappears by conversion to fixed-rate pacing, thereby eliminating all arrhythmias specifically related to the sensing circuit. This report describes partial sensing by normally functioning demand pacemakers from borderline signals due to low bipolar ventricular electrograms in two patients and originating from the T wave in the third patients. The recognition that this particular arrhythmia stems from the delivery of an inadequate signal to a pacemaker rather than true pacemaker failure may avoid unnecessary replacement of normally functioning pulse generators.
Black Box Multigrid with coarsening by a factor of three

Black Box Multigrid (BoxMG) is a robust variational multigrid solver for diffusion equations on logically structured grids. BoxMG standardly uses coarsening by a factor of two. It handles cell-centered discretizations on logically rectangular grids by treating the cell-centers as the unknowns to be coarsened. Such a strategy does not preserve the cell structure. That is, coarse-grid cells are not the union of fine-grid cells. In some applications, such as local grid refinement, it is desirable that the cell structure be preserved. In this paper, we develop a method that employs coarsening by a factor of three. It is a natural generalization of standard BoxMG, using operator-induced interpolation (which approximately preserves the continuity of the normal flux), restriction as the transpose of interpolation, and Galerkin coarsening. In addition, we introduce a new colored block Gauss–Seidel scheme that is motivated by the form of the interpolation operator, dubbed ‘pattern’ relaxation. We present numerical results that demonstrate robustness of this method with respect to discontinuous diffusion coefficients, boundary conditions, and grid dimension. Published in 2010 by John Wiley & Sons, Ltd.
Distribution of alpha 1 subunit isoform of (Na,K)-ATPase in the rat spinal cord.

Three isoforms of the alpha subunit of (Na,K)-ATPase have been identified in the rat central nervous system. Using a probe specific for the alpha 1 isoform, mRNA levels were measured from five sections of the rat spinal cord using slot blot techniques. Assigning a value of 1 to the slope obtained from the cervical section, the upper thoracic section was 2.6 times higher; the midthoracic section was 4.5 times higher; the lower thoracic section was 2.6 times higher; and the lumbar section was 1.7 times higher. The results suggest that alpha 1 isoform mRNA levels are not uniform throughout the spinal cord. In situ hybridization techniques showed that alpha 1 isoform mRNA was diffusely abundant in glial and central canal ependymal cells, while labeled neurons were localized exclusively in lateraily located anterior horn neurons in cervical, thoracic, and lumbar segments and in ventromedial neurons in mid-thoracic spinal cord. Also, dorsal root ganglia neurons were extensively labeled at all segments.
Self‐management theory for developing teacher effectiveness: A new pedagogic approach to teacher effectiveness

(1992). Self‐management theory for developing teacher effectiveness: A new pedagogic approach to teacher effectiveness. The Teacher Educator: Vol. 28, No. 2, pp. 27-33.
Global variables and identified hadrons in the PHENIX experiment

PHENIX measurements related to global variables and identified hadrons are discussed. These include two-pion correlations, elliptic flow, and dN/dη. Measurements of event-by-event fluctuations in mean transverse momentum, mean transverse energy, and net charge are presented for particles within the PHENIX acceptance. The centrality dependence of these measurements is also discussed.
Progesterone-Independent Activation of Rat Brain Progestin Receptors by Reproductive Stimuli

Activation of steroid hormone receptors by steroid hormones alters both the physiology and behavior of animals. Steroid hormone receptors (e.g., progestin receptors) can also be activated in the absence of steroid hormones by pharmacological treatment with neurotransmitters or neuropeptides. However, it is not known if progesterone-independent activation of brain progestin receptors occurs under natural, physiological, conditions. We report that increases in reproductive behavior and brain immediate early gene expression in female rats induced by mating stimuli can be blocked by prior treatment with progesterone antagonists in the absence of circulating progesterone. This suggests that progestin receptors are activated in a progesterone-independent manner by a physiologically relevant stimulus in female rats, thus implicating a novel pathway by which mating stimuli and other environmental influences could activate steroid receptors to influence neuronal response and behavior.
Magnetotunnelling measurements of localized optical phonons in GaAs/AlAs double-barrier structures

We have measured current-voltage characteristics at liquid-helium temperature and for magnetic fields up to 7T(parallel to the current flow) for three similar asymmetric GaAs/AlAs double-barrier structures, all of which possess large phonon-assisted tunnelling currents. Confined longitudinal optical (LO) phonons in the GaAs well layer and LO-like symmetric interface phonons treated within a dielectric continuum picture suffice to account for the measured currents. Phonon-assisted tunnelling current levels as well as magnetotunnelling data are found to depend sensitively on well and barrier widths.
Molecular characterization of neurotransmitter transporters.

Rapid chemical signaling between neurons and target cells is dependent upon the precise control of the concentration and duration of neurotransmitters in synaptic spaces. After transmitter release from activated nerve terminals, the principal mechanism involved in the rapid clearance from the synapse of the biogenic amine and amino acid neurotransmitters is active transport of the transmitter back into presynaptic nerve terminals or glial surrounding cells by one of a large number of specific, pharmacologically distinguishable membrane transport proteins (1). High affinity, Na+-dependent uptake activities, analogous to the noradrenergic carrier first described at peripheral synapses by Axelrod and colleagues (2) have been identified in mammalian central nervous system (CNS) nerve terminals for the biogenie amine neurotransmitters including norepinephrine (NE), dopamine (DA), and serotonin (5HT) for the excitatory amino acid neurotransmitters L-glutamate and L-aspartate, and for the inhibitory amino acid neurotransmitters r-amino butyric acid (GABA) and glycine (3). The primary function of plasma membrane neurotransmitter transporters is to clear the synapse of the neurotransmitter between nerve impulses and to replenish neurotransmitter levels in presynaptic nerve terminals. In certain cases, Na+-dependent transport processes may also mediate the presynaptic accumulation of neurotransmitter precursors as well. For example, the rate-limiting step in the biosynthesis of acetylcholine appears to be Na+dependent choline uptake into cholinergic nerve terminals by a hemicholiniumsensitive high affinity choline transporter (5). Neurotransmitter transporters represent critical targets for therapeutic and pathological alterations of synaptic function. This is particularly apparent with the tricyclic antidepressants, amphetamines, and cocaine, agents that block biogenic amine transport and produce dramatic behavioral changes (6). Abnormalities of neurotransmitter transport can contribute to neuropathol-
The Spontaneous Magnetization of a Two-Dimensional Ising Model

The spontaneous magnetization of a two-dimensional Ising model is calculated exactly. The result also gives the long-range order in the lattice.
Cosmological perturbations on local systems

We study the effect of cosmological expansion on orbits - galactic, planetary, or atomic - subject to an inverse-square force law. We obtain the laws of motion for gravitational or electrical interactions from general relativity - in particular, we find the gravitational field of a mass distribution in an expanding universe by applying perturbation theory to the Robertson-Walker metric. Cosmological expansion induces an (a'/a)r-vector force where a(t) is the cosmological scale factor. In a locally Newtonian framework, we show that the (a'/a)r-vector term represents the effect of a continuous distribution of cosmological material in Hubble flow, and that the total force on an object, due to the cosmological material plus the matter perturbation, can be represented as the negative gradient of a gravitational potential whose source is the material actually present. We also consider the effect on local dynamics of the cosmological constant. We calculate the perihelion precession of elliptical orbits due to the cosmological constant induced force, and work out generalizations to the rotation curve and virial relation applicable to clusters of galaxies.
A Procedure for the Fractionation of Aqueous Aluminum in Dilute Acidic Waters

Abstract A procedure was developed for the fractionation of aqueous aluminum. This procedure results in the determination of acid-soluble aluminum, non-labile monomeric aluminum and labile monomeric aluminum. Acid-soluble aluminum is thought to include colloidal aluminum and extremely non-labile organic complexes. Non-labile monomeric aluminum is thought to include monomeric alumino-organic complexes. Labile monomeric is comprised of aquo aluminum as well as inorganic complexes of aluminum. The inorganic speciation of aluminum may be calculated by using labile monomeric aluminum, pH, fluoride and sulfate data with a chemical equilibrium model. This procedure was evaluated using synthetic and natural water solutions. In natural waters, levels of labile monomeric aluminum increased exponentially with decreases in solution pH, while non-labile monomeric aluminum was strongly correlated with organic carbon concentration. Non-labile monomeric aluminum was observed to be relatively insensitive to changes in sol...
A Model for Pharmacokinetics and Physiological Feedback among Hormones of the Testicular-Pituitary Axis in Adult Male Rats: A Framework for Evaluating Effects of Endocrine Active Compounds

The testicular-hypothalamic-pituitary axis controls reproductive functions in males. A description of the basic physiological interactions in adult rats among testosterone, luteinizing hormone (LH), and follicle stimulating hormone (FSH) was developed, permitting simulation of hormone levels in testes and blood. This model was used to simulate hormone levels in intact, castrate, ethane dimethanesulfonate-treated, and antiandrogen-treated rats. A large gradient of testosterone concentrations from testicular interstitial fluid to low levels in peripheral blood is created by the testicular blood flow. The dominant feedback loop is positive regulation of testosterone synthesis by LH and negative feedback of testosterone on LH and FSH. The utility of the model for placing in vitro data in the context of in vivo physiology was illustrated for the case of continued synthesis of testosterone by the isolated testes. In the absence of blood flow, very low residual testosterone synthesis can substantially increase testosterone concentration in isolated testes. Effects of an exogenous endocrine active compound were illustrated by modeling altered LH and FSH regulation by testosterone in the presence of an antiandrogen acting as a competitive ligand for the androgen receptor. Increasing concentrations have no effect on steady-state hormone levels until sufficient levels of antiandrogen are achieved to reduce negative feedback of testosterone on LH and FSH. In summary, a model has been developed that provides a basis for initiating evaluations of key issues of concern for the risk assessment of endocrine active compounds including in vitro to in vivo extrapolation and their dose-response behaviors.
At what price? The current state of subject payment in adolescent research

Abstract Purpose To examine how subject payment was associated with study features, such as investigator characteristics and project specifics, among randomly selected studies using adolescent subjects. Methods Using Psychinfo we gathered a list of original research studies published in 1999 that used adolescent subjects. We randomly selected corresponding authors and mailed confidential questionnaires on subject payment. We gathered complete data from 127 authors of adolescent research. While our main outcome was subject payment, we also examined the monetary value and form of the payment. Predictor variables included the principal investigator's demographics and professional information and the project's design and sample. Data were analyzed using Student's t -tests, Pearson correlations, and logistic regression. Results Of the studies using adolescent subjects, 55% (n = 61) involved payment. Total payment varied (range $1 to $600, mean=$82.35) and the mean value per session was $26.61. Investigator characteristics associated with payment were a principal investigator's current discipline area and the decade, level and area of highest educational degree obtained. Funding and protocol complexity were related to payment, as was the sample's size, gender composition, ethnic makeup, SES distribution, and at-risk status. Logistic regression analyses found that researchers using payment were 7.2 times more likely to have funding, 2.8 times more likely to work with at-risk youth, and for every unit increase in positive attitude toward compensation, there was a 1.1-fold increase in the likelihood of using payment. Conclusions Of those who responded to our questionnaire, slightly more than one-half the 1999 published studies done with adolescents used payment; however, the amount paid varied tremendously.
Molluscan Models in Evolutionary Biology: Apple Snails (Gastropoda: Ampullariidae) as a System for Addressing Fundamental Questions*

Abstract: Molluscs constitute the second largest phylum in terms of the number of described species and possess a wide array of characteristics and adaptations for living in marine, terrestrial, and freshwater habitats. They are morphologically diverse and appear in the fossil record as far back as the early Cambrian (∼560 mybp). Despite their high diversity and long evolutionary history, molluscs are often underused as models for the study of general aspects of evolutionary biology. Freshwater snails in the family Ampullariidae have a global tropical and subtropical distribution and high diversity with more than 150 species in nine currently recognized genera, making them an ideal group to address questions of historical biogeography and some of the underlying mechanisms of speciation. They exhibit a wide range of morphological, behavioral, and physiological adaptations that have probably played a role in the processes of diversification. Here we review some of the salient aspects of ampullariid evolutio...
Pseudomonas aeruginosa Host Immune Evasion

The opportunistic pathogen Pseudomonas aeruginosa is a common cause of pneumonia in immunocompromised and mechanically ventilated patients. By virtue of its large genome and genetic flexibility, P. aeruginosa is able to adapt to its environment regulating the expression of a large repertoire of virulence factors. It is capable of forming biofilms that favor persistence and evasion of phagocytic clearance. Within a biofilm the bacteria communicate via soluble quorum sensors regulating production of elastases and proteases. P. aeruginosa is able to modify expression of pathogen associated molecular patterns such that recognition by host immune receptors is minimized. The bacteria are also able to subvert the innate immune system through direct interaction with host cells and host immune cytokines. These strategies of immune evasion and the genetic pathways that regulate them have contributed to the unusual success of P. aeruginosa as on opportunistic pathogen.
Fanin ordering in multi-shot timing analysis

A method for fan-in ordering of commutative functions in combinational logic is described. The objective is to maximise the worst slack in a multislot timing analysis environment. The main contribution is the notion that the problem can be formulated as a bipartite matching problem, in which the minimum weight of any element is maximised. The advantage of the method is that it gives optimal results over a large range of delay models. The optimization problem can be solved exactly in O(n/sup 2/ square root n In n) time, where n is the number of commutative pins, and only n timing calculations are necessary. >
Sintering of sputtered copper nanoparticles on (001) copper substrates

The sintering of sputtered copper nanoparticles with a thin film copper substrate has been studied in real time using a novel in-situ UHV TEM. Particles were generated by dc sputtering in argon and transferred directly into the microscope along a connecting tube. The particles were deposited onto a clean (001) copper substrate of thickness 40nm. As-deposited particles assume a random orientation on the copper substrate as evidenced by electron diffraction patterns. Upon annealing, however, the particles were observed to reorient and assume the orientation of the substrate. Reorientation of individual, isolated particles occurred at ∼200°C, primarily by grain-boundary motion and not by surface diffusion.
β2-Adrenergic receptor density and cardiovascular response to mental stress

Abstract In this study we evaluated effects of an acute experimental stressor on β 2 -adrenoceptor density and examined the relationships of baseline receptor density to cardiovascular reactions induced by stress. In addition, we investigated whether any observed alterations in receptor density were associated with concomitant redistribution of circulating lymphocyte populations. Receptor density and lymphocyte subsets were determined before and immediately following performance of a frustrating laboratory task in 22 male volunteers. Blood pressure, heart rate (HR), and plasma catecholamine concentrations were also assessed at baseline and during task performance. Parallel measurements were obtained among 11 unstressed control subjects. Receptor density increased significantly between baseline and posttask measurements, but equally so in experimental and control subjects. Numbers of T suppressor/cytotoxic and natural killer cells increased selectively among subjects assigned to the experimental (stress) condition. However, there was no association between lymphocyte subset distribution and receptor density. Interindividual variability in pretask receptor density correlated significantly with heart rate and systolic blood pressure (SBP) reactivity during the initial 3 min of mental stress, but not over the entire task period. In addition, baseline receptor density correlated with SBP (but not HR) reactivity after covariance adjustment for the concomitant change in plasma catecholamine concentrations.
The Celebrity-Icon:

This article develops a non-reductive approach to celebrity, treating it as an iconic form of collective representation central to the meaningful construction of contemporary society. Like other compelling material symbols, the celebrity-icon is structured by the interplay of surface and depth. The surface is an aesthetic structure whose sensuous qualities command attention and compel attachment; the depth projects the sacred and profane binaries that structure meaning even in postmodern societies. While celebrity worship displays elements of totemism, it also reflects the eschatological hopes for salvation that mark post-Axial Age religion. The attacks on celebrity culture that inform critical public and intellectual thinking resemble iconoclastic criticisms of idol worship more than they do empirical social scientific study.
Laterally mobile, functionalized self-assembled monolayers at the fluorous-aqueous interface in a plug-based microfluidic system: characterization and testing with membrane protein crystallization.

This paper describes a method to generate functionalizable, mobile self-assembled monolayers (SAMs) in plug-based microfluidics. Control of interfaces is advancing studies of biological interfaces, heterogeneous reactions, and nanotechnology. SAMs have been useful for such studies, but they are not laterally mobile. Lipid-based methods, though mobile, are not easily amenable to setting up the hundreds of experiments necessary for crystallization screening. Here we demonstrate a method, complementary to current SAM and lipid methods, for rapidly generating mobile, functionalized SAMs. This method relies on plugs, droplets surrounded by a fluorous carrier fluid, to rapidly explore chemical space. Specifically, we implemented his-tag binding chemistry to design a new fluorinated amphiphile, RfNTA, using an improved one-step synthesis of RfOEG under Mitsunobu conditions. RfNTA introduces specific binding of protein at the fluorous−aqueous interface, which concentrates and orients proteins at the interface, even in the presence of other surfactants. We then applied this approach to the crystallization of a his-tagged membrane protein, Reaction Center from Rhodobacter sphaeroides, performed 2400 crystallization trials, and showed that this approach can increase the range of crystal-producing conditions, the success rate at a given condition, the rate of nucleation, and the quality of the crystal formed.
An X-band spacecraft transponder for deep space applications-design concepts and breadboard performance

The design concepts and measured performance characteristics of an X-band breadboard deep-space transponder (DST) for future spacecraft applications are summarized. The DST consists of a double-conversion, superheterodyne, automatic phase tracking receiver, and an X-band exciter to drive redundant downlink power amplifiers. The receiver acquires and coherently phase tracks the modulated or unmodulated X-band uplink carrier signal. The exciter phase modulates the X-band downlink signal with composite telemetry and ranging signals. The measured tracking threshold, automatic gain control (AGC), static phase error, and phase jitter characteristics of the breadboard DST are in good agreement with the expected performance. The measured results show a receiver tracking threshold of -158 dBm and a dynamic signal range of 88 dB. >
Monitoring of Nonsteroidal Immunosuppressive Drugs in Patients With Lung Disease and Lung Transplant Recipients: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

Objectives Immunosuppressive pharmacologic agents prescribed to patients with diffuse interstitial and inflammatory lung disease and lung transplant recipients are associated with potential risks for adverse reactions. Strategies for minimizing such risks include administering these drugs according to established, safe protocols; monitoring to detect manifestations of toxicity; and patient education. Hence, an evidence-based guideline for physicians can improve safety and optimize the likelihood of a successful outcome. To maximize the likelihood that these agents will be used safely, the American College of Chest Physicians established a committee to examine the clinical evidence for the administration and monitoring of immunosuppressive drugs (with the exception of corticosteroids) to identify associated toxicities associated with each drug and appropriate protocols for monitoring these agents. Methods Committee members developed and refined a series of questions about toxicities of immunosuppressives and current approaches to administration and monitoring. A systematic review was carried out by the American College of Chest Physicians. Committee members were supplied with this information and created this evidence-based guideline. Conclusions It is hoped that these guidelines will improve patient safety when immunosuppressive drugs are given to lung transplant recipients and to patients with diffuse interstitial lung disease.