cssi/SciSciGPT-SciSciNet huggingface dataset:
A radiometric microassay for choline acetyltransferase. Some observations on the spinal cord of the chicken embryo

This paper describes cation-exchange methods for separating acetyl[3H] coenzyme A from [acetyl-3H]choline. Blanks for the routine method were approximately 0.05% of the substrate radioactivity; product recoveries were approximately 97%. The cation-exchange method was moreefficient than the standard methods using either anion-exchange chromatography or periodide precipitation. The cation-exchange method was also morespecific than either of the other two standard methods for estimating choline acetyltransferase (ChAT) activity. ChAT activity was detected in the chicken lumbar spinal cord on embryonic day (E) 2 1/4 with the cation-exchange method. This developmental stage is about 6 hours before the final mitosis of any neuroblast in the ventral horn. Total ChAT activity per lumbar spinal cord increased more than 10,000-fold between E 3 and E 18. Changes in ChAT activity in the lumbar spinal cord following limb-bud extirpation appeared to mirror (with a phase lag) the changes in the number of motoneurons in the lateral motor column.
Incorporation of Tritium-labelled Thymidine and Tritium-labelled Deoxycytidylic Acid into Deoxyribonucleic Acid after Irradiation of the Deoxyribonucleic Acid Primer with γ-Rays

RECENTLY, Kornberg et al. 1 have demonstrated that deoxyribonucleic acid formed in vitro by enzymatic synthesis has chemical and physical properties similar to the acid used as primer. Since exposure to radiation is known to cause chemical changes in deoxyribonucleic acid2–4, it was thought that such changes might be reflected in the newly synthesized acid. In an attempt to study this, we have determined the ability of irradiated and non-irradiated deoxyribonucleic acid to incorporate tritium-labelled thymidine or tritium-labelled deoxycytidylic acid in the presence of the deoxyribonucleic acid-synthesizing enzyme system from regenerating rat liver.
Synthesis of a new class of polydentate ligands: [bis(2-imidazolyl)methyl] amino-thioether-thiols

Abstract A new class of polydentate bis(imidazole)-thioether-thiol polydentate ligands has been synthesized by the reactions of functionalized primary amines with bis(2-imidazolyl)nitromethane. The molecules contain a bis(2-imidazolyl)methylamino group attached to chains of varying length with thiol (3, 23) and thioether/thiol (7,11,15,19) binding sites.
Sprouty2-modulated Kras signaling rescues Shp2 deficiency during lens and lacrimal gland development

Shp2/Ptpn11 tyrosine phosphatase is a general regulator of the RTK pathways. By genetic ablation, we demonstrate that Shp2 is required for lacrimal gland budding, lens cell proliferation, survival and differentiation. Shp2 deletion disrupted ERK signaling and cell cycle regulation, which could be partially compensated by activated Kras signaling, confirming that Ras signaling was the main downstream target of Shp2 in lens and lacrimal gland development. We also showed that Sprouty2, a general suppressor of Ras signaling, was regulated by Shp2 positively at the transcriptional level and negatively at the post-translational level. Only in the absence of Sprouty2 could activated Kras signaling robustly rescue the lens proliferation and lacrimal-gland-budding defects in the Shp2 mutants. We propose that the dynamic regulation of Sprouty by Shp2 might be important not only for modulating Ras signaling in lens and lacrimal gland development, but also for RTK signaling in general.
Tentoxin effects on variable fluorescence and P515 electrochromic absorbance changes in tentoxin-sensitive and -resistant plant species

Abstract The effects of the cyclic tetrapeptide phytotoxin, tentoxin, on variable chlorophyll fluorescence quenching and the P515 electrochromic absorbance change were examined in tentoxin-sensitive and -resistant species and an interspecies hybrid. Immediately after infiltration of leaf discs, up to 100 μM tentoxin had no effect on the O, I, D, or P portions of the fluoresence transients of either tentoxin-sensitive or -resistant plants. However, the quenching of fluorescence following maximal fluorescence was reduced by approximately fourfold in tentoxin-treated tissues of tentoxin-sensitive plants, but was unaffected in resistant plants. Tentoxin significantly increased the magnitude of the P515 electrochromic absorbance change in all tentoxin sensitive plants by an average of approximately twofold. However, it was unaffected by tentoxin in resistant species. These data suggest that there is a close correlation between interaction of tentoxin with CF1 ATPase in vivo and the ability to cause chlorosis in developing chloroplasts.
Characterizing Self-Heating in Multiwalled Carbon Nanotube Coated Piezoceramic Sheet Actuators

In this paper we investigate the technical feasibility of minimizing self-heating in piezoceramic sheet actuators using carbon nanotube thin film coatings. Our hypothesis is that the enhanced active surface area provided by the carbon nanotube coating will significantly enhance heat dissipation to the atmosphere. To demonstrate this concept multiwalled carbon nanotube films were deposited on the surfaces of PZT-5H piezoceramic sheets. The multiwalled nanotube coating results in significant reduction in power consumption compared to the baseline uncoated actuator (for the same induced-strain level). By comparing the surface temperature of the baseline (or uncoated) and nanotube coated piezo sheet we confirmed that the observed reduction in current and power consumption is related to improved convection of heat energy from the piezo surface.
A variational formulation and a double-grid method for meso-scale modeling of stressed grain growth in polycrystalline materials

A deterministic approach for meso-scale modeling of grain growth in stressed polycrystalline materials based on the principle of virtual power is presented. The variational equation is formulated based on the power balance of the system associated with grain boundary surface tension and curvature, rate of strain energy stored in each grain, strain energy density jump across the grain boundaries, and external work rate. The numerical solution of stressed grain growth variational equation requires discretization of grain interiors and grain boundaries. This cannot be effectively modeled by Lagrangian, Eulerian, or Arbitrary Lagrangian Eulerian finite element method if grain boundary migration (moving interfaces) and topological changes of grain boundary geometry are considered. This paper presents a double-grid method to resolve the above mentioned difficulty. In this approach, the material grid points carry material kinematic variables, whereas the grain boundary grid points carry grain boundary kinematic variables. The material domain is discretized by a moving least squares reproducing kernel approximation with strain discontinuity enrichment across the grain boundaries. The grain boundaries, on the other hand, are discretized by the standard finite elements. An interface enrichment function to accurately capture strain jump conditions across the grain boundaries is introduced. A reproducing kernel approximation that includes the periodicity of the unit cell in the construction of reproducing kernel shape function for material velocity is also presented. This proposed double-grid method allows modeling of arbitrary evolution of grain boundaries without remeshing.
Shared Decision Making — The Pinnacle of Patient-Centered Care

The most important attribute of patient-centered care is the active engagement of patients when fateful health care decisions must be made — when they arrive at a crossroads of medical options, where diverging paths have different and important consequences.
Debate-induced Opinion Change What Matters?

In this article, we focus on the extent and sources of attitude change produced by the second 1996 presidential debate. First, we test the magnitude of attitude change brought about by the 1996 deb...
The Fourier transform

To calculate a transform, just listen. The ear automatically performs the calculation, which the intellect can execute only after years of mathematical education. The ear formulates a transform by converting sound-the waves of pressure traveling through time and the atmosphere-into a spectrum, a description of the sound as a series of volumes at distinct pitches. The brain turns this information into perceived sound. Similar operations can be done by mathematical methods on sound waves or virtually any other fluctuating phenomenon, from light waves to ocean tides to solar cycles. These mathematical tools can decompose functions representing such fluctuations into a set of sinusoidal components-undulating curves that vary from a maximum to a minimum and back, much like the heights of ocean waves. The Fourier transform is a function that describes the amplitude and phase of each sinusoid, which corresponds to a specific frequency. The Fourier transform has become a powerful tool in diverse fields of science. In some cases, the Fourier transform can provide a means of solving unwieldy equations that describe dynamic response to electricity, hear or light. In other cases, it can identify the regular contributions to a fluctuating signal, thereby helping to make sense of observations inmore » astronomy, medicine and chemistry.« less
The Oracle Sparc T5 16-Core Processor Scales to Eight Sockets

The Oracle Sparc T5 processor more than doubles the throughput of the Sparc T4 processor, while increasing per-thread performance, scalability, power efficiency, and I/O bandwidth. The authors detail the improvements and new features leading to this latest Oracle Sparc processor.
Brief self-report measure of work-related cognitive limitations in breast cancer survivors

The purpose of this research was to develop a brief, reliable self-report measure of work-related cognitive limitations in occupationally active breast cancer survivors. A pooled dataset of working breast cancer survivors (n = 228) completed a self-report measure of work-related cognitive limitations, the Cognitive Symptom Checklist-Work-59 (CSC-W59). A cross-validation technique was employed such that the pooled participants were randomized into two separate groups in order to conduct exploratory factor analysis (EFA) of the CSC-W59 with one group (n = 114) and confirm the results with the second group (n = 114). EFA of the CSC-W59 identified 21 items with a consistent factor loading of .4 or higher on three separate subscales (Working Memory, Executive Function, and Task Completion). These findings resulted in a 21-item, self-report measure referred to as the Cognitive Symptom Checklist-Work-21 (CSC-W21). The CSC-W21 demonstrated internal reliability (α = .88). Construct validity of the CSC-W21 is supported by significant positive correlations with cancer stage, job stress, and affective state. Brief, valid, internally reliable self-report measures such as the CSC-W21 may be used to quickly assess work-related cognitive problems for breast cancer survivors at work. A brief measure is available to help identify tasks that present problems for breast cancer survivors who are at work. This measure can be used to facilitate research to improve the understanding and mitigation of cognitive challenges in breast cancer survivors in the work setting.
Pavlovian reward prediction and receipt in schizophrenia: relationship to anhedonia.

Reward processing abnormalities have been implicated in the pathophysiology of negative symptoms such as anhedonia and avolition in schizophrenia. However, studies examining neural responses to reward anticipation and receipt have largely relied on instrumental tasks, which may confound reward processing abnormalities with deficits in response selection and execution. 25 chronic, medicated outpatients with schizophrenia and 20 healthy controls underwent functional magnetic resonance imaging using a Pavlovian reward prediction paradigm with no response requirements. Subjects passively viewed cues that predicted subsequent receipt of monetary reward or non-reward, and blood-oxygen-level-dependent signal was measured at the time of cue presentation and receipt. At the group level, neural responses to both reward anticipation and receipt were largely similar between groups. At the time of cue presentation, striatal anticipatory responses did not differ between patients and controls. Right anterior insula demonstrated greater activation for nonreward than reward cues in controls, and for reward than nonreward cues in patients. At the time of receipt, robust responses to receipt of reward vs. nonreward were seen in striatum, midbrain, and frontal cortex in both groups. Furthermore, both groups demonstrated responses to unexpected versus expected outcomes in cortical areas including bilateral dorsolateral prefrontal cortex. Individual difference analyses in patients revealed an association between physical anhedonia and activity in ventral striatum and ventromedial prefrontal cortex during anticipation of reward, in which greater anhedonia severity was associated with reduced activation to money versus no-money cues. In ventromedial prefrontal cortex, this relationship held among both controls and patients, suggesting a relationship between anticipatory activity and anhedonia irrespective of diagnosis. These findings suggest that in the absence of response requirements, brain responses to reward receipt are largely intact in medicated individuals with chronic schizophrenia, while reward anticipation responses in left ventral striatum are reduced in those patients with greater anhedonia severity.
Effects of Children's Understanding of Time Concepts on Historical Understanding

Abstract There are many articles on how children learn clock, calendar, and historical time skills and concepts. Few attempts have been made, however, to explain the relationships between learning time and learning history. Research on children's understanding of time, and three views of how this understanding affects their understanding of history, are presented. It is suggested that each of the three views implies a different conception of effective instruction in history. Finally, an alternative view of how temporal and historical understandings affect the teaching of history called the developmental-historical time view is proposed.
The energetics of allosteric regulation of ADP release from myosin heads

Myosin molecules are involved in a wide range of transport and contractile activities in cells. A single myosin head functions through its ATPase reaction as a force generator and as a mechanosensor, and when two or more myosin heads work together in moving along an actin filament, the interplay between these mechanisms contributes to collective myosin behaviors. For example, the interplay between force-generating and force-sensing mechanisms coordinates the two heads of a myosin V molecule in its hand-over-hand processive stepping along an actin filament. In muscle, it contributes to the Fenn effect and smooth muscle latch. In both examples, a key force-sensing mechanism is the regulation of ADP release via interhead forces that are generated upon actin–myosin binding. Here we present a model describing the mechanism of allosteric regulation of ADP release from myosin heads as a change, ΔΔG−D, in the standard free energy for ADP release that results from the work, Δμmech, performed by that myosin head upon ADP release, or ΔΔG−D = Δμmech. We show that this model is consistent with previous measurements for strain-dependent kinetics of ADP release in both myosin V and muscle myosin II. The model makes explicit the energetic cost of accelerating ADP release, showing that acceleration of ADP release during myosin V processivity requires ∼4 kT of energy whereas the energetic cost for accelerating ADP release in a myosin II-based actin motility assay is only ∼0.4 kT. The model also predicts that the acceleration of ADP release involves a dissipation of interhead forces. To test this prediction, we use an in vitro motility assay to show that the acceleration of ADP release from both smooth and skeletal muscle myosin II correlates with a decrease in interhead force. Our analyses provide clear energetic constraints for models of the allosteric regulation of ADP release and provide novel, testable insights into muscle and myosin V function.
Properties of Poly(tetramethylene Oxide)-Poly(tetramethylene Terephthalate) block polymers

Abstract Properties of block copolymers were studied by SALS, dynamic mechanical testing, DSC, and stress-strain and dichroism experiments. Crystallization of hard segments provides a superstructure for the elastomer phase consisting of uncrystallized hard and soft segments.
On minimisation of word length of multidimensional filter realisations

In this paper, we present a statistical word length minimisation procedure based on the dynamical model of stable-unstable transitions in N-dimensional digital filters. This dynamical model [1] was originally used to determine a priori, for a worst case design, the minimum word length of the multipliers needed to retain stability. In this contribution, the dynamical model of stable-unstable transitions in N-dimensional filters is used to estimate each multiplier's minimum word length sufficient, in some statistical sense, to retain stability. The new procedure has been compared with the worst case procedure. It has been found that the present procedure results in a significant saving of the word length in comparison with the worst case analysis. The method is therefore an attractive alternative to the worst case procedure. Numerical examples are solved at the end to illustrate the procedure presented.
Methods for Quantifying Ultrasound Backscatter and Two-Dimensional Video Intensity: Implications for Contrast-Enhanced Sonography

Abstract Quantification of acoustic backscatter energy is believed to be useful for assessing "tissue character" and for quantifying the regional concentration of echo contrast. Measurement of ultrasonic video intensity has been the traditional means of quantifying backscatter energy, with "integrated backscatter" considered the gold standard. The purpose of this work is to review the commonly used methods for quantifying ultrasonic backscatter and to describe the difference between detected backscatter energy and the intrinsic tissue backscatter coefficient. Many of the quantification pitfalls that can lead to erroneous conclusions will also be discussed. A set of eight rubber phantoms with backscatter coefficient from -6 dB to +15 dB relative to liver were imaged at 2.5, 3.5, and 5.0 MHz. Methods for calculating the acoustic backscatter intensity from calibrated video intensity measurements and for calculating the tissue backscatter coefficient are described and tested using equipment from two different manufacturers. A commercially available automatic "acoustic densitometry" system with on-board quantitative integrated backscatter is also evaluated. Ultrasound attenuation and ultrasound system factors were found to strongly influence the detected backscatter intensity using either calibrated video intensity or on-board integrated backscatter. Special system transfer functions and attenuation correction were found to be useful in converting video intensity and integrated backscatter to a measure of the intrinsic tissue backscatter coefficient. With these correction factors, the correlation between the measured tissue backscatter coefficient and the phantom backscatter coefficient was excellent ( r = 0.99, intercept 0.0, regression slope essentially 1.0) at all three imaging frequencies with traditional video intensity or on-board integrated backscatter. Uncalibrated video intensity and on-board integrated backscatter have limitations when used in isolation for tissue characterization. Rigorous attention to the imaging parameters and the use of calibration functions are necessary before video intensity measurement or integrated backscatter can be used reliably to measure the tissue backscatter coefficient. (J Am Soc Echocardiogr 1998;11:155–68)
Autoerotic Asphyxia: The Development of a Paraphilia

The authors studied five adolescent male practitioners of autoerotic asphyxia to determine contributors to its etiology. Extensive histories including detailed sexual histories were obtained from each boy. Their life histories suggested an early history of choking, in combination with physical or sexual abuse, was related to the development of autoerotic asphyxia. Each boy appeared to have paired choking with sexual arousal, and autoerotic asphyxia was a persisting behavior pattern for four of five boys. This sample is the largest study of living practitioners of this behavior and suggests the heretofore unmentioned history of either choking or abuse.
Racial differences of parameters associated with blood pressure levels in children--the Bogalusa heart study.

Abstract Racial differences in prevalence of essential hypertension are well known. In order to explore these differences at an early age in terms of etiology, we investigated schoolchildren in an entire, biracial community. A sample of 278 children, stratified by diastolic (fourth-phase) blood pressure and specific for age, race, and sex, was reexamined 1–2 yr after initial observation for the following: (1) a physical examination and urinalysis to exclude secondary hypertension; (2) 24-hr urine sodium, potassium, plasma renin activity, and serum dopamine β-hydroxylase; (3) 1-hr oral glucose tolerance test; and (4) heart rate and blood pressure at rest and under standarized physical stress. We found that 24-hr urine sodium was positively associated with blood pressure level as measured on the same day for the high blood pressure strata of black children. Urine potassium excretion was lower in blacks than in whites, although their intakes seemed equal. In the high blood pressure strata especially, black boys had lower renin activity than whites, and the resting-supine and stressed systolic blood pressures were higher in black boys than in any other group. In these black boys, resting and stressed systolic pressures were negatively related to plasma renin activity. On the other hand, dopamine β-hydroxylase levels in white children were higher than in blacks for all blood pressure strate, and in the high blood pressure strata white children had higher 1-hr glucose levels and faster resting heart rates than black children. Different mechanisms may play a role in and contribute to the early stage of essential hypertension.
Effects of red clover decomposition on phytotoxicity to wild mustard seedling growth.

Previous studies have suggested that phenolics from legume green manures may contribute to weed control through allelopathy. The objective of this study was to determine how decomposition of red clover (Trifolium pratense L.) residue affects phytotoxicity to a weed species, wild mustard (Sinapis arvensis L.). Red clover (1.25 g), 30 g acid washed sand, and 5 ml of microbial inoculant were incubated in the dark at 14°C. The incubations were conducted in sand to allow the determination of decomposition phytotoxicity effects without being confounded by soil sorption effects. Aqueous extracts were collected at 0, 1, 2 and 5 weeks. The extracts were analyzed for dissolved organic carbon (DOC) and phenolic carbon (PhC). Phytotoxicity of the extracts was estimated by comparing root elongation under sterile laboratory conditions. The red clover extract significantly reduced radicle growth in the bioassay, but there was no significant change in the degree of phytotoxicity over the 5-week decomposition period. Although the concentration of DOC decreased with increasing decomposition, the PhC concentration was not significantly affected. This suggests that in the absence of soil sorbants, the phytotoxic compounds are stable throughout the 5-week incubation period and are phenolic in nature. This study demonstrates that the potential exists for using legume green manures to be a component of a sustainable weed management system, but indicates that soil characteristics need to be factored in evaluating the potential for this weed control tool.
Correlation of the time course of development and decay of tolerance to morphine with alterations in sodium pump protein isoform abundance

Abstract Since the heterologous tolerance that develops after chronic morphine administration has been proposed to be an adaptive process, it follows that the time course of the change in the cellular components should coincide with the time course of the altered responsiveness. This study correlated the time course over which heterologous tolerance develops with changes in the abundance of selected proteins in the guinea-pig longitudinal muscle/myenteric plexus (LM/MP) preparation. Tissues were obtained at various times following a single surgical implantation procedure and heterologous tolerance confirmed by a significant reduction in the sensitivity of the LM/MP to inhibition of neurogenic twitches by morphine, DAMGO, and 2-CADO. Tolerance developed with a delayed onset (significant 2–5-fold reduction in sensitivity by day 4 after pellet implantation) that reached a maximum by 7 days (4–8-fold reduction in responsiveness) that was maintained through 14 days with normal sensitivity spontaneously returning by 21 days post-implantation. Dot blot analysis was used to examine the abundance of the alpha1 and alpha3 subunit isoforms of the Na+/K+ ATPase and beta-actin over the same time course. The results showed significant decreases in abundance of the alpha3 subunit at 4, 7, and 10 days following pellet implantation but no change in beta-actin or the alpha1 subunit at any time period. These data support the idea that heterologous tolerance following chronic morphine exposure results from a cellular adaptive change that may involve a change in the abundance of the alpha3 subunit isoform of the Na+/K+ ATPase.
Electronic excitation of the b 3Σu state of H2 by electron impact in the linear algebraic approach

The authors have performed two-state close-coupling calculations on the X 1 Sigma g to b 3 Sigma u transition for e-H2 scattering within the linear algebraic, effective optical potential approach. The strong orthogonality constraint between bound and continuum orbitals is relaxed by including correlation-type configurations. These correlation terms prove to be very important in the 2 Sigma g and 2 Sigma u symmetries and lead to an increase in the total cross section of a factor of two over earlier approaches, which neglected these terms. The authors obtain good agreement with recent R-matrix and Schwinger variational calculations.
Decentralized Policies for Geometric Pattern Formation and Path Coverage

This paper presents a decentralized control policy for symmetric formations in multiagent systems. It is shown that n agents, each one pursuing its leading neighbor along the line of sight rotated by a common offset angle a, eventually converge to a single point, a circle or a logarithmic spiral pattern, depending on the value of a. In the final part of the paper, we present a strategy to make the agents totally anonymous, and we discuss a potential application to coverage path planning.
Eolian deflation by ancient katabatic winds: A late Quaternary example from the north Alaska Range

Strong katabatic winds are frequently generated in glaciated mountain valleys of the Alaska Range by downglacier gravitational flow of chilled air. Stronger katabatic winds probably occurred during late Quaternary time, when glaciers were more extensive, and such winds may have greatly influenced eolian sedimentation. In Nenana River valley and in most of adjacent Teklanika River valley, the entire 1- to 2-m-thick eolian cap is postglacial in age, and the beginning of loess deposition coincides almost exactly with rapid recession of late Wisconsin ice. Previously deposited loess and bluff-edge dunes were apparently deflated during the last glaciation between 25,000 and 12,000 yr B.P. Loess deposition in these mountain valleys thus is exclusively an interglacial phenomenon; glacial phases are characterized by deflation. Meteorological modeling of katabatic winds generated during the last glaciation predicts that paleowind velocities greatly exceeded the entrainment thresholds required for eolian deflation. When both Nenana River and Teklanika River valleys are compared, theoretical differences in the potential for generating katabatic winds and differences in valley physiography explain why pre-Holocene loess is preserved in downstream reaches of Teklanika River valley and not Nenana River valley. The presence of strong katabatic winds in mountain valleys beyond former glacier limits has significant implications for late Pleistocene paleoecology and archeology.
Selective extraction of N2 from air by diarylimine iron complexes.

Treatment of cis-(Me3P)4FeMe2 with ortho-substituted diarylimines afforded 2 equiv of MeH, PMe3, and {mer-κC,N,C′-(Ar-2-yl)CH2N═CH(Ar′-2-yl)}Fe(PMe3)3 (Ar = 3,4,6-(F)3-C6H, Ar′ = 3,5-(CF3)2-C6H2, 1a; Ar = 3,4,6-(F)3-C6H, Ar′ = 3,4,5-(F)3-C6H, 1b; Ar = 4,5,6-(F)3-C6H, Ar′ = 3,5-(CF3)2-C6H2, 1c; Ar = C6H4, Ar′ = 3-(OMe)-C6H3, 1d; Ar = 4,5,6-(F)3-C6H, Ar′ = 3,6-Me2-C6H3, 1e; Ar = C6H4, Ar′ = 3,6-Me2-C6H2, 1f). Exposure of 1a–f to O2 caused rapid degradation, but substitution of the unique PMe3 with N2 occurred when 1a–f were exposed to air or N2 (1 atm), yielding {mer-κC,N,C′-(Ar-2-yl)CH2N═CH(Ar′-2-yl)}Fe(PMe3)2L (L = N2, 2a–f); CO, CNMe, and N2CPh2 derivatives (L = CO, 3a–d,f; L = CNMe, 8b; L = N2CPh2, 9b) were prepared. Dihydrogen or NH3 binding to {mer-κC,N,C′-(3,4,6-(F)3-C6H-2-yl)CH2N═CH-(3,4,5-(F)3-C6H-2-yl)}Fe(PMe3)2 (1b′, S = 1 (calc)) to provide 5b (L = H2) or 6b (L = NH3) was found comparable to that of N2, while PMe3 (1b) and pyridine (L = py, 7b) adducts were unfavorable. Protolytic conditions wer...
Pulsed e± Annihilation γ-Ray Line from a Crab-like Pulsar

Electron-positron pair production and annihilation within the magnetosphere of a γ-ray pulsar such as the Crab are considered. Outer-magnetosphere accelerator models seem capable of giving both the 1040 s-1 e± pair annihilation rate and the narrow, gravitationally redshifted e± annihilation line shape in the Crab pulsar spectrum reported by the FIGARO collaboration. An essential feature is the expected formation of an electron-positron layer well above the pulsar surface, in which gravitational pull toward the star is balanced by cyclotron resonance scattering of polar cap X-rays. Applications to other γ-ray pulsars with smaller spin-down powers than that of the Crab pulsar are also considered.
Statistical mechanics of nucleation: incorporating translational and rotational free energy into thermodynamics of a microdroplet.

Motivated by the original Lothe-Pound prescription, we derive a formula for the replacement partition function that is suitable for vapor to liquid phase nucleation in terms of the classical phase integral. The resulting expression was evaluated for truncated and shifted Lennard-Jones fluids by means of computer simulation. The corresponding Lothe-Pound correction factor, which is to multiply the classical expression for the nucleation rate, decreases significantly with increasing temperature and decreasing cluster size, and is in the range of 10 9 ‐10 13 for the temperatures and the cluster sizes we studied. This is somewhat smaller than the original estimate of 10 17 by Lothe and Pound.
Involuntary tobacco smoke exposure and urinary levels of polycyclic aromatic hydrocarbons in the United States, 1999 to 2002.

Evidence supports active smoking as a major source of exposure to polycyclic aromatic hydrocarbons (PAH), compounds that are mutagenic and carcinogenic in humans. The influence of involuntary exposure to tobacco smoke on PAH exposure levels among nonsmokers, however, is unknown. This study evaluated the association between both active and involuntary tobacco smoke and biomarkers of PAH exposure in the general U.S. population. A cross-sectional analysis of 5,060 participants ≥6 years of age was done using data from the 1999-2002 National Health and Nutrition Examination Survey (NHANES). PAH exposure was measured by urinary concentrations of 23 monohydroxylated metabolites of nine PAH compounds. Tobacco smoke exposure was defined as no exposure, involuntary exposure, and active exposure by combining serum cotinine levels, smoking status, and presence of household smokers. PAH metabolite levels ranged from 33.9 ng/L for 9-hydroxyphenanthrene to 2,465.4 ng/L for 2-hydroxynaphthalene. After adjustment for age, sex, race/ethnicity, education, household income, and broiled/grilled food consumption, participants involuntarily and actively exposed to tobacco smoke had urinary metabolite concentrations that were increased by a factor of 1.1 to 1.4 and 1.5 to 6.9, respectively, compared with unexposed participants. Associations for involuntary smoking were stronger and statistically significant for 1-hydroxypyrene, 2-hydroxyfluorene, 3-hydroxyfluorene, 9-hydroxyfluorene, 1-hydroxyphenanthrene, 2-hydroxyphenanthrene, and 3-hydroxyphenanthrene compared with other metabolites. Involuntary exposure to tobacco smoke was associated with elevated urinary concentrations of most PAH metabolites in a representative sample of the U.S. population. Policy and educational efforts must continue to minimize PAH exposure through active and involuntary tobacco smoke exposure. (Cancer Epidemiol Biomarkers Prev 2009;18(3):884–93)
Effect of loading and geometry on the subsonic/intersonic transition of a bimaterial interface crack

Abstract An experimental investigation was conducted to study the nature of intersonic crack propagation along a bimaterial interface. A single edge notch/crack oriented along a polymer/metal interface was loaded predominantly in shear by impacting the specimen with a high velocity projectile fired from a gas gun. The stress field information around the propagating crack tip was recorded in real time by two different optical techniques––photoelasticity and coherent gradient sensing, in conjunction with high speed photography. Intersonic cracks on polymer/metal interfaces were found to propagate at speeds between the shear wave speed (cs) and 2 c s of the polymer. The nature of the crack tip fields during subsonic/intersonic transition and the conditions governing this transition were examined. Experimental observations showed the formation of a crack face contact zone as the interfacial crack speed exceeds the Rayleigh wave speed of the polymer. Subsequently, the contact zone was observed to expand in size, shrink and eventually collapse onto the intersonic crack tip. The recorded isochromatic fringe patterns showed multiple Mach wave formation associated with such a scenario. It is found that the nature of contact zone formation as well as its size and evolution differ substantially depending on the sign of the opening component of loading.
Bulk processing of high-performance nanocrystalline intermetallics

We present an inexpensive, bulk-processing technique for the mass fabrication of a high-performance, nanocrystalline intermetallic with no internal flaws: the recrystallization of plastically deformed ingots through controlled heat treatments. We demonstrate that FeCo alloys with average grain sizes of 100 nm can be produced using this method. The nanocrystalline materials have tensile yield strengths as high as 2.2 GPa and have plastic tensile ductilities over 1.3%. Such superior properties at room temperature are currently unattainable when nanocrystalline materials are prepared by other methods.
Quantitative determination of fluvastatin in human plasma by gas chromatography/negative ion chemical ionization mass spectrometry using [18O2]‐fluvastatin as an internal standard

A sensitive and specific method for the quantitative determination of fluvastatin in human plasma is presented. The drug was isolated from plasma by extractive alkylation with pentafluorobenzyl bromide and further derivatized to the bis-trimethylsilyl derivative. [18O2]-Fluvastatin was prepared from unlabelled fluvastatin and used as an internal standard. Gas chromatography/mass spectrometry under negative ion chemical ionization conditions was used for quantitative measurement of the drug, using m/z 554.26 and 558.26 for target and internal standard, respectively. Calibration graphs were linear within a range of 2 and 512 ng mL(-1) plasma. Intra-day precision was 0.94% (2 ng mL(-1)), 2.53% (8.2 ng mL(-1)), 2.16% (81.9 ng mL(-1)) and 3.26% (409.6 ng mL(-1)); inter-day variability was found to be 1.64% (2 ng mL(-1)), 0.97% (8.2 ng mL(-1)), 1.97% (81.9 ng mL(-1)) and 2.01% (409.6 ng mL(-1)). Intra-day accuracy showed deviations of 0.6% (2 ng mL(-1)), 0.37% (8.2 ng mL(-1)), -1.52% (81.9 ng mL(-1)) and -1.67% (409.6 ng mL(-1)); inter-day accuracy was of -1.64% (2 ng mL(-1)), -1.13% (8.2 ng mL(-1)), -2.28% (81.9 ng mL(-1)) and -0.46% (409.6 ng mL(-1)). The stable isotope labelled standard was found to be stable under the analytical conditions.
Genetic testing for long QT syndrome and the category of cardiac ion channelopathies.

Cardiac ion channel mutational analysis is a category of genetic testing used in clinical practice for determining the status of long QT syndrome, short QT syndrome, catecholaminergic polymorphic ventricular tachycardia, and Brugada syndrome genes in blood, saliva, or tissue from patients and family members at risk for cardiac events such as syncope and sudden death. Such testing is most informative following careful phenotypic characterization. Individuals with ion channelopathies may benefit from prevention (avoidance of triggers and predisposing drugs) and treatment (e.g., beta blocker therapy, implantable cardioverter-defibrillator (ICD) placement) modalities. Abstract Cardiac ion channel mutational analysis is a category of genetic testing used in clinical practice for determining the status of long QT syndrome, short QT syndrome, catecholaminergic polymorphic ventricular tachycardia, and Brugada syndrome genes in blood, saliva, or tissue from patients and family members at risk for cardiac events such as syncope and sudden death. Such testing is most informative following careful phenotypic characterization. Individuals with ion channelopathies may benefit from prevention (avoidance of triggers and predisposing drugs) and treatment (e.g., beta blocker therapy, implantable cardioverter-defibrillator (ICD) placement) modalities. Abstract Cardiac ion channel mutational analysis is a category of genetic testing used in clinical practice for determining the status of long QT syndrome, short QT syndrome, catecholaminergic polymorphic ventricular tachycardia, and Brugada syndrome genes in blood, saliva, or tissue from patients and family members at risk for cardiac events such as syncope and sudden death. Such testing is most informative following careful phenotypic characterization. Individuals with ion channelopathies may benefit from prevention (avoidance of triggers and predisposing drugs) and treatment (e.g., beta blocker therapy, implantable cardioverter-defibrillator (ICD) placement) modalities.
Quantum discord for two-qubit X states: Analytical formula with very small worst-case error

Quantum discord is a measure of quantum correlation beyond entanglement. Computing quantum discord for simple quantum states is a basic problem. An analytical formula of quantum discord for two-qubit $X$ states is first claimed in [Ali, Rau, and Alber, Phys. Rev. A 81, 042105 (2010)], but later found to be not always correct. I observe numerically that the formula is valid with worst-case absolute error 0.0021. For symmetric two-qubit $X$ states, I give a counterexample to the analytical formula derived in [F. F. Fanchini et al., Phys. Rev. A 81, 052107 (2010)], but observe that the formula is valid with worst-case absolute error 0.0006. The formula has been used in many research papers. The results in all these works are approximately correct, even if they may not be exactly correct.
Circuit-level techniques to control gate leakage for sub-100 nm CMOS

Although still negligible for state-of-the-art CMOS, gate leakage will become significant in the future for sub-100 nm technologies, due to the scaling of oxide thickness. We propose several circuit techniques to control gate leakage based on the fact that PMOS transistors with SiO/sub 2/ gate oxide have an order of magnitude smaller gate leakage than NMOS transistors in the same technology. First, we compare n-type domino with p-type domino circuits in terms of performance, leakage and switching power, and explore the different trade-offs between performance and power. Second, we compare n-type with p-type gating for MTCMOS to control the leakage during sleep. The proposed circuits are simulated for a predictive 70 nm CMOS technology with 10 /spl Aring/ gate oxide thickness and 1.2 V supply voltage.
Report on XEWA-00: the XML enabled wide-area searches for bioinformatics workshop

The XEWA-00 workshop, held in December 2000 and sponsored by the IEEE Computer Society, was organized to bring together members of the bioinformatics community to determine if XML could simplify accessing large, heterogeneous, distributed collections of web-based data sources. The starting point for a series of breakout and group discussions was a proposed strawman of a grammar that described how to query a data source through its web interface. As a result of these discussions, the approach was validated, the strawman was refined, and several reference implementations are being generated as part of an ongoing effort. This article contains an overview of the workshop, including the proposed approach and a description of the strawman.
Oceanographic telecommuting: Going to sea virtually

Oceanography in the 21st century is on the verge of changing the way it does business. Telecommuting from office to sea is about to make the same impact as telecommuting between home and the office did 20 years ago. A recent geophysical survey highlighted the role that telecommuting will soon play in ocean research. In June 2005, R/V Knorr was in the middle of the Atlantic Ocean conducting a geophysical survey of a region centered at 13°N along the Mid-Atlantic Ridge in the general area of the diffuse triple junction between the North America (NA), Africa (AF),and South America (SA) plates. This region is particularly notable because of a unique zone of seismicity that occurs ∼70 km west of the ridge axis between 14°20′N and 12°50′N. The survey conducted on this cruise (KN182–3) was a first step toward understanding how slow spreading lithosphere is deforming in the NA-SA-AF triple junction region.
Does context matter in evaluations of stigmatized individuals? An fMRI study

The manner in which disparate affective responses shape attitudes toward other individuals has received a great deal of attention in neuroscience research. However, the malleability of these affective responses remains largely unexplored. The perceived controllability of a stigma (whether or not the bearer of the stigma is perceived as being responsible for his or her condition) has been found to polarize behavioral affective responses to that stigma. The current study uses functional magnetic resonance imaging to identify the neural correlates underlying the evaluation of stigmatized individuals (people who are homeless) when perceptions of the controllability of their condition are altered. Results demonstrated that perceivers engaged neural networks implicated in inferring intentionality (e.g. the medial prefrontal cortex) when they evaluated a homeless individual who was described as being responsible for becoming homeless. Conversely, neural networks associated with resolving strong affective responses (e.g. insula) were engaged when evaluating a homeless individual who was described as not being responsible for becoming homeless.
THE ANTIQUITY OF AFRICAN TORTOISES

(2003). The antiquity of African tortoises. Journal of Vertebrate Paleontology: Vol. 23, No. 3, pp. 688-690.
CIDS: An agent-based intrusion detection system

The paper describes security agent architecture, called CIDS, which is useful as an administrative tool for intrusion detection. Specifically, it is an agent-based monitoring and detection system, which is developed to detect malfunctions, faults, abnormalities, misuse, deviations, intrusions, and provide recommendations (in the form of common intrusion detection language). The CIDS can simultaneously monitor networked-computer activities at multiple levels (user to packet level) in order to find correlation among the deviated values (from the normal or defined policy) to determine specific security violations. The current version of CIDS (CIDS 1.4) is tested with different simulated attacks in an isolated network, and some of those results are reported here.
Gamones and mating types in the genus Blepharisma and their possible taxonomic application

Mating types I and II of Blepharisma japonicum v. intermedium excrete gamones 1 (blepharmone J) and 2 (blepharismone) respectively. The gamone of one type transforms cells of the other type so that they can conjugate with each other. We found that three other species, B. americanum, B. musculus and B. stoltei , have two types of cells homologous to those in B. japonicum ; one (type II) excretes a factor which has the same activity as gamone 2 of B. japonicum , the other (type I) responds to this gamone by cell union. Type I cells of these species also excrete a gamone which induces pairs in type II cells of particular strains. Complementarity for mating is observed in some combinations of the two types. These results indicate that each of the four species has at least one pair of complementary mating types, I and II, with the gamones of the type II's being the same molecule, blepharismone, while gamones of type I's are species- or syngen-specific blepharmone. These generic and specific gamones can be utilized to clarify existing taxonomic and evolutionary questions in the genus Blepharisma .
Criteria predicting response to CRT: is more better?

The quest for the perfect parameter to predict response to cardiac resynchronization therapy (CRT) suffered a major setback when two prospective trials (PROSPECT and ReTHINQ) demonstrated limitations in the potential clinical value of the much-touted tissue Doppler velocity-based criteria.1,2 Until then there was a steady stream of ‘highly accurate’ predictors of response to CRT.3–5 Notwithstanding the bevy of potential technical issues plaguing these studies, they did successfully raise serious doubts about how the clinical community and vendors were going about identifying patients likely to respond to CRT. We have always been of the opinion that attempting to solve a complex issue such as predicting response to CRT by means of a single binary parameter, such as tissue Doppler velocity-derived delays, is overly simplistic. For what it is worth, several studies over thousands of patients do indicate some value to testing dyssynchrony using tissue velocities.6 In a similar vein, our take on PROSPECT and ReTHINQ is that they do not convincingly repudiate the notion that a dyssynchronous heart is more likely to respond to CRT. In that regard it is heartening to see a study examine the value of using multiple parameters to predict response to CRT. Lafitte and colleagues examined parameters of dyssynchrony at multiple functional levels including atrioventricular, interventricular and intraventricular.7 The strengths of this study include: size ( n = 181), multicentre design, all patients fulfilled standard clinical criteria for CRT (New York Heart Association class II–IV, ejection fraction 120 ms) and a large proportion of ‘responders’ to CRT (57%). The authors used a relatively well-validated index of response, namely a ≥15% decrease in left ventricular end-systolic volume. Feasibility of measurement was high (∼80%) at acceptable variability of … *Corresponding author. Tel: +1 410 502 7974, Fax: +1 410 955 1509, Email: tabraha3{at}jhmi.edu
Acute obstructive renal failure secondary to granulocytic sarcoma (Chloroma)

We report an unusual case of bilateral ureteral obstruction secondary to granulocytic sarcoma of the uterine cervix. Proximal urinary diversion followed by radiation therapy to the tumor relieved the obstruction. The need for prompt diagnosis and treatment of this rare neoplasm is stressed.