cssi/SciSciGPT-SciSciNet huggingface dataset:
Stress and telomere shortening: Insights from cellular mechanisms.

Short telomeres confer risk of degenerative diseases. Chronic psychological stress can lead to disease through many pathways, and research from in vitro studies to human longitudinal studies has pointed to stress-induced telomere damage as an important pathway. However, there has not been a comprehensive model to describe how changes in stress physiology and neuroendocrine pathways can lead to changes in telomere biology. Critically short telomeres or the collapse of the telomere structure caused by displacement of telomere binding protein complex shelterin elicit a DNA damage response and lead to senescence or apoptosis. In this narrative review, we summarize the key roles glucocorticoids, reactive oxygen species (ROS) and mitochondria, and inflammation play in mediating the relationship between psychological stress and telomere maintenance. We emphasis that these mediators are inter-connected and reinforce each other in positive feedback loops. Telomere length has not been studied across the lifespan yet, but the initial setting point at birth appears to be the most influential point, as it sets the lifetime trajectory, and is influenced by stress. We describe two types of intergenerational stress effects on telomeres - prenatal stress effects on telomeres during fetal development, and 'telotype transmission" -the directly inherited transmission of short telomeres from parental germline. It is clear that the initial simplistic view of telomere length as a mitotic clock has evolved into a far more complex picture of both transgenerational telomere influences, and of interconnected molecular and cellular pathways and networks, as hallmarks of aging where telomere maintenance is a key player interacting with mitochondria. Further mechanistic investigations, testing this comprehensive model of stress mediators shaping telomere biology and the telomere-mitochondrial nexus will lead to better understanding from cell to human lifespan aging, and could lead to anti-aging interventions.
Thermoelastic Pressure Waves in Canonical Head Models

This chapter presents rigorous multidisciplinary, mathematical analyses of the thermoelastic pressure wave generated in spherical human and animal heads exposed to pulsed microwave radiation. The results include dependence of induced sound pressure frequency and strength on microwave pulse characteristics. It provides information on the attributes of sound wave generated in the head as perceived by humans. It summarizes the first mathematical models for analyzing the sound pressure waves inside the head due to a microwave pulse and generalizations of the methodology to arbitrary SAR patterns of spherical symmetry. It also includes comparisons of predicted and measured response characteristics in human and animal heads.
Micromagnetics of Longitudinal Recording Media

Future needs in high density magnetic storage devices require increases both in linear and track densities. The latest 1 Gigabit per square inch areal density for longitudinal media demonstrated by IBM1 has reduced the bit size to dimensions comparable to the characteristic micromagnetic length scales of todays media. Improvement or extension of the current recording limits requires detailed knowledge of micromagnetics and their manipulation or tailoring through the microstructure of the utilized magnetic thin films.
Quasi-Linear Parameter Varying Representation of General Aircraft Dynamics Over Non-Trim Region

For applying linear parameter varying (LPV) control synthesis and analysis to a nonlinear system, it is required that a nonlinear system be represented in the form of an LPV model. In this paper, a new representation method is developed to construct an LPV model from a nonlinear mathematical model without the restriction that an operating point must be in the neighborhood of equilibrium points. An LPV model constructed by the new method preserves local stabilities of the original nonlinear system at "frozen" scheduling parameters and also represents the original nonlinear dynamics of a system over a non-trim region. An LPV model of the motion of FASER (Free-flying Aircraft for Subscale Experimental Research) is constructed by the new method.
Routing with Delays when Storage is Costly

A model for computer networks is considered in which there is a cost associated with both the transmission of data across network links, and the storage of data at network nodes. Requests for data specify the time at which the data is to be used — early arrival therefore has no advantage, and has the disadvantage that the data must be stored at the node, accruing the related costs. A wide variety of data routing and broadcast problems are considered for this model. Efficient algorithms for solving some of these problems are presented; others are proven intractable.
Career mobility as a Poisson process

Abstract Poisson process models of upward mobility in job rewards are developed and estimated using event history techniques on data from one organization over a period of 80 years. The models developed permit the inclusion of independent variables which vary over a person's career and are used to analyze differences in the mobility of men and women. The main findings are (1) the career dynamics of men and women are similar in general form, both best described by a segmented, heterogeneous, and nonstationary Poisson process; (2) parametric differences exist between the models for men and women in terms of how certain independent variables affect the rate of arrival of opportunities to move up in the reward hierarchy and in terms of how others affect the rate of being given or taking advantage of such opportunities; and (3) both men and women appear to benefit by being in competition with one another for available opportunities. Theoretical interpretations of these results are discussed in relation to differences in the flow of opportunities to locations in the reward hierarchy occupied predominantly by men versus those occupied predominantly by women.
Animal phylogenomics: multiple interspecific genome comparisons.

Abstract The utility of DNA sequence information for phylogenetics and phylogeography is now well known. Rather than attempt to summarize studies addressing this well-demonstrated utility, this chapter focuses on fundamental approaches and techniques that implement the collection of DNA sequence data for comparative phylogenetic purposes in a genomic context (phylogenomics). Whole genome sequencing approaches have changed the way we think about phylogenetics and have opened the way for new perspectives on “old” phylogenetics concerns. Some of these concerns are which gene regions to use and how much sequence information is needed for robust phylogenetic inference. Whole genome sequences of a few animal model organisms have gone a long way to implement approaches to better understand these important phylogenetic concerns. This chapter also addresses how genomics has made it more important for a clear understanding of orthology of gene regions in comparative biology. Finally, genome-enabled technologies that are affecting comparative biology are also discussed.
Sampling-based lower bounds for counting queries

It is well known that the problem of computing relative approximations of weighted counting queries such as the probability of evidence in a Bayesian network, the partition function of a Markov network, and the number of solutions of a constraint satisfaction problem is NP-hard. In this paper, we settle therefore on an easier problem of computing high-confidence lower bounds. We propose to use importance sampling and Markov inequality for solving it. However, a straight-forward application of the Markov inequality often yields poor lower bounds. We therefore propose several new schemes for improving its performance in practice. Empirically, we show that our new schemes are quite powerful, often yielding substantially higher (better) lower bounds than all state-of-the-art schemes.
News Framing and Charter School Reform

This paper reviews the historical development of charter schools and the ways in which charter schools are currently viewed by the American public. Using the tools of news framing analysis, the study also examines a sample of news reports from The Washington Post, The New York Times, and The Philadelphia Inquirer in order to identify dominant news frames. This process reveals two dominant frames -- Public Accountability, and Freedom, Choice, and Innovation – which are illustrated with excerpts from the news sample. The paper concludes by considering the implications of these frames for charter school reform and suggests several new directions for scholarship in this area.
MR cardiac imaging using breath-hold gradient echo acquisition

Despite the progress in fast scan MRI techniques, it has not been possible to routinely image the heart rapidly enough so as to collect all image data during one breath-hold. Cardiac images are therefore degraded by respiratory motion during several minutes of data acquisition. Fast scan images also have limited SNR and inadequate myocardium-to-chamber contrast. The purpose of this work was to address these limitations by blood suppression, centric or centric-like view ordering, and data acquisition in diastole with 2DFT and 3DFT gradient echo acquisition. High resolution black-blood cardiac images were acquired. The endocardial surface is very well delineated. In a series of 13 volunteer studies these methods have consistently provided superior quality visualization of intraventricular structures. The authors believe the images are a significant improvement over previous results generated with gradient echo and echo-planar techniques, and rival high quality gated spin-echo results. >
Conflict-Induced Displacement, Understanding the Causes of Flight

This study investigates circumstances that affect individuals' decisions of whether or not to flee their homes during civilian conflicts. Building on the "choice-centered" approach to studying forced migration, I test the argument that people make a decision to flee or stay even under highly dangerous circumstances. Using primary data collected through a public opinion survey in Nepal, I test a number of hypotheses regarding the impact of factors such as violence, economic opportunity, physical infrastructure or geographical terrain, and social networks on forced migration, providing an individual-level test of the choice-centered approach to studying forced migration. The empirical results are consistent with the major hypotheses developed in aggregate-level studies and provide better insights into the factors that affect individual-level behavior. Beyond conflict, there are a number of significant economic, social, physical, and political factors that affect individuals' choice to flee. Language: en
Long-term outcome of cyclocryotherapy for refractory pediatric glaucoma

Abstract Objective To evaluate the success rate and long-term outcome of cyclocryotherapy for refractory pediatric glaucoma. Design Retrospective interventional case series. Participants A total of 64 eyes of 49 patients from 2 institutions with pediatric glaucomas resistant to conventional medical and surgical therapies treated with cyclocryotherapy from 1975 to 1996 were included in this review. Intervention Cyclocryotherapy was performed on eyes with pediatric glaucoma resistant to maximal medical and surgical interventions. Each cyclocryotherapy session was evaluated in terms of area treated, temperature, and number of applications placed. Main outcome measures Criteria for success included intraocular pressure (IOP) of 21 mmHg or less without devastating complications or need for further glaucoma surgery. Results The mean baseline pretreatment IOP of all eyes was 30.0 ± 8.1 mmHg. Six months after their last treatment, 42 eyes (66%) were successes. Longer term follow-up (mean, 4.8 ± 3.3 years) yielded a lower final success rate in 28 eyes (44%). For these 28 eyes, mean IOP was reduced from 30.3 ± 7.8 mmHg pretreatment to 16.8 ± 4.0 mmHg after their last cyclocryotherapy treatment session (P P Conclusion Cyclocryotherapy is an effective means of lowering IOP and is a reasonable treatment option in selected pediatric patients with refractory glaucoma. Eyes with aniridia experienced a very high rate of phthisis after cyclocryotherapy and may be poor candidates for this treatment.
Dancing the numinous: sacred and spiritual techniques of contemporary American belly dancers.

In this paper, I explore how contemporary American practitioners of belly dance (as Middle Eastern dance and its many varieties are often called in the English-speaking world) conceptualize not only the spiritual dimensions of their dance, but also how the very notion of performance affects sacred and spiritual dance practices. Drawing on interviews with this community, I describe the techniques of sacred and spiritual belly dancers, how these dancers theorize performance, and how the conflicts inherent to patriarchal mind-body dualism are resolved in these practices. My purpose here is twofold: to document an emergent dance tradition and to analyze its meanings in the relevant social context.
Adherence to combined montelukast and fluticasone treatment in economically disadvantaged african american youth with asthma.

High rates of asthma treatment nonadherence have been reported, particularly in economically disadvantaged African American youth. The relationship between adherence to combined medication treatment and asthma outcomes has potential clinical significance but is not well understood. Using electronic monitoring, we describe the pattern of adherence to daily corticosteroid (fluticasone) and leukotriene receptor antagonist (montelukast) medication over the course of 1 year in a population of African American youth with moderate to severe asthma. On average, adherence to montelukast was higher than adherence to fluticasone (p < 0.01); however, for both medications, adherence rates significantly declined over the course of the study. After 1 year, participants took only 31% of prescribed doses of montelukast and 23% of prescribed doses of fluticasone. The decline in adherence to both fluticasone (p < 0.05) and montelukast (p < 0.001) was related to increased healthcare utilization. Furthermore, asthma symptom r...
The Six Basic Concepts of Consciousness and William James's Stream of Thought:

The present article utilizes the six basic concepts of consciousness for the purpose of clarifying the nature and characteristics of William James's stream of awareness. Simultaneously, an effort is made to render these concepts more understandable as referring to different properties and kinds of properties of a single basic phenomenon. Thus, a second purpose of this article is implicitly to relate and integrate the six concepts by bringing them to bear on the stream of awareness.
Sexual Transmission of Disease and Host Mating Systems: Within-Season Reproductive Success

While there is an extensive literature on the evolution of mating systems in animals, little consideration has been given to the possible evolutionary interactions between sexually transmitted pathogens and the mating systems of their hosts. We use individual-based models that incorporate measurable per-contact probabilities of infection and fertilization to show that not only can the presence of sexually transmitted (and sterilizing) pathogen have significant effects on optimal within-season mating strategies for both males and females. We show that, contrary to expectations, monogamy is not always predicted to be the optimal strategy. The optimal strategy may also often differ between the two sexes, and the optimal strategy will not always be the one that minimizes disease transmission. Similarly, we show that the optimal level of virulence for a sexually transmitted pathogen is a function of the degree of promiscuity of its host. Overall, these results suggest that sexually transmitted diseases can imp...
Application of the generalized 2D correlation analysis to dynamic near-edge X-ray absorption spectroscopy data.

Application of the generalized 2D correlation analysis to a series of in situ XANES spectra enabled the determination of additional useful information not readily available from the conventional spectra. In addition to the changes in the intensity of the white line and in the pre-edge feature, readily observable in the regular spectra, the generalized 2D correlation analysis clearly evidenced an otherwise imperceptible shift in the main edge energy caused by the gradual reduction of Co 2+ to metallic cobalt. The 2D correlation spectra also allowed the establishment of a time sequence for the changes occurring in the spectral features during hydrogen reduction, which provides valuable information on the reduction mechanism. While the generalized 2D correlation analysis was found to be very useful in obtaining supplementary information from the series of XANES spectra analyzed, interpretation of the correlation intensities should be checked for consistency with the general trend of each spectral feature, as spectral intensities that do not change monotonically may induce changes in the signs of the correlation intensities leading to inaccurately establishing sequences of changes among the spectral features in the series.
Structure of yeast regulatory gene LEU3 and evidence that LEU3 itself is under general amino acid control

Determination of the nucleotide sequence of a DNA region from Saccharomyces cerevisiae previously shown to contain the LEU3 gene revealed one long open reading frame (ORF) whose 887 codons predict the existence of a protein with a molecular mass of 100,162 daltons. The codon bias index of 0.02 suggests that LEU3 encodes a low-abundance protein. The predicted amino acid sequence contains a stretch of 31 residues near the N-terminus that is rich in cysteines and basic amino acids and shows strong homology to similar regions in five other regulatory proteins of lower eukaryotes. Additional regions with a predominance of basic amino acids are present adjacent to the cysteine-rich region. A stretch of 20 residues, 19 of which are glu or asp, is found in the carboxy terminal quarter of the protein. The 5' flanking region of LEU3 contains a TATA box 111 bp upstream from the beginning of the long ORF and two transcription initiation elements (5'TCAA3') 58 and 48 bp upstream from the ORF. The 3' flanking region shows a tripartite potential termination-polyadenylation signal. The predicted 5' and 3' ends of the transcript are in very good agreement with the previously determined size of the LEU3 message. Analysis of a LEU3'-'lacZ translational fusion suggests that the LEU3 gene, whose product is involved in the specific regulation of the leucine and possibly the isoleucine-valine pathways, is itself under general amino acid control. Consistent with this observation is the finding that the 5' flanking region of LEU3 contains two perfect copies of the general control target sequence 5'TGACTC3'.
Results and complications of total hip arthroplasties in patients with sickle-cell hemoglobinopathies: Role of cementless components

Abstract The complications and results of 16 primary and revision total hip arthroplasties in patients with sickle-cell hemoglobinopathies were evaluated. One patient died from renal failure at 1 year, leaving 15 hips in 10 patients for review at a mean follow-up period of 6 years (range, 2–12 years). There were 7 cementless primary total hip arthroplasties and 8 revision arthroplasties, 6 of which were uncemented. Patients were evaluated clinically using a standard hip rating system and radiographically using accepted criteria. There were no early or late deep infections; however, 7 of 8 primary arthroplasties and 5 of 8 revisions had one or more early complications. No cementless component demonstrated loosening; however, there was asymptomatic polyethylene wear in 2 primary arthroplasties, treated with grafting and liner exchange, and femoral osteolysis was present in 4 of 13 cementless arthroplasties, one of which was revised to permit extensive grafting. Of the original 15 arthroplasties performed by the senior author, 5 required some type of reoperation during the study. At most recent follow-up evaluation, no component in the study was radiographically loose. In the hips that did not require reoperation, the overall results were excellent in 6 hips, good in 3, and poor in 1 hip. Of the 5 hips requiring reoperation, the results were excellent in 3 hips, good in 1, and fair in 1 hip at most recent follow-up evaluation. Cementless components should be considered for all primary and revision arthroplasties in patients with sickle-cell hemoglobinopathies, but early complications are frequent and a high incidence of polyethylene wear and osteolysis requiring reoperation may be expected.
HIV-1 treatment as prevention: the good, the bad, and the challenges

Purpose of review This work focuses on the use of antiretroviral agents to prevent the sexual transmission of HIV-1. Recent findings Two randomized clinical trials demonstrated that antiretroviral agents provided before exposure to HIV-1 offer substantial protection, ostensibly directly proportional to the concentration of antiretroviral therapy (ART) in the genital secretions. Intense focus on the use of HIV treatment as prevention has led to publication of modeling exercises, ecological studies, and observational studies, most of which support the potential benefits of ART. However, the logistical requirements for successful use of ART for prevention are considerable. Summary ART will serve as a cornerstone of combination prevention of HIV-1. Continued research will be essential to measure anticipated benefits and to detect implementation barriers and untoward consequences of such a program, especially increases in primary ART resistance.
Calcified granulomatous disease: occupational associations and lack of familial aggregation.

Purpose The acute host response to histoplasma capsulatum infection varies according to exposure and susceptibility. Late sequelae include calcifications in the lung, thoracic lymphatics, and spleen. Determinants of calcified granuloma formation are poorly studied and may differ from those affecting acute response. We examined the occupational associations and familial aggregation of radiographic calcified granulomatous disease to characterize the determinants of calcified granuloma formation.
Venezuelan equine encephalitis virus infection of mosquito cells requires acidification as well as mosquito homologs of the endocytic proteins Rab5 and Rab7

Venezuelan equine encephalitis virus (VEEV) is a New World alphavirus that can cause fatal encephalitis in humans. It remains a naturally emerging disease as well as a highly developed biological weapon. VEEV is transmitted to humans in nature by mosquito vectors. Little is known about VEEV entry, especially in mosquito cells. Here, a novel luciferase-based virus entry assay is used to show that the entry of VEEV into mosquito cells requires acidification. Furthermore, mosquito homologs of key human proteins (Rab5 and Rab7) involved in endocytosis were isolated and characterized. Rab5 is found on early endosomes and Rab7 on late endosomes and both are important for VEEV entry in mammalian cells. Each was shown to have analogous function in mosquito cells to that seen in mammalian cells. The wild-type, dominant negative and constitutively active mutants were then used to demonstrate that VEEV requires passage through early and late endosomes before infection can take place. This work indicates that the infection mechanism in mosquitoes and mammals is through a common and ancient evolutionarily conserved pathway.
Translating Hemoglobin A1c into Average Blood Glucose: Implications for Clinical Chemistry

Measurement of hemoglobin A1c (Hb A1c)1 is a fundamental component of the management of patients with diabetes mellitus. Hb A1c measurement provides an indication of chronic exposure to glucose and is extensively used for both monitoring long-term glycemic status and evaluating whether an individual patient has attained adequate metabolic control. The patient’s Hb A1c value is used by clinicians to determine whether glucose-lowering therapy is adequate. A recent report (1) establishes a mathematical relationship between Hb A1c and the average glucose (AG) concentration in blood. The findings presented are likely to have considerable impact on the way Hb A1c is reported by clinical laboratories and used by healthcare providers (and patients). The importance and potential consequences of the study are the focus of this Perspective. The efficacy of therapy to lower blood glucose in patients with diabetes mellitus is assessed by 2 complementary methods, glucose measurement, which is performed by patients, and Hb A1c measurement. Patients perform self-monitoring of blood glucose (SMBG) by using hand-held meters to measure their own blood glucose concentrations. It is recommended that patients on insulin perform SMBG 4 times a day. The dose of the insulin injection is determined by the glucose value. Many modern meters store the results of all the glucose measurements, which can be downloaded and accessed by the physician during the patient’s visit. The second method for monitoring therapy to lower blood glucose is measurement of glycohemoglobin, most commonly performed by assaying Hb A1c. Glycohemoglobin is formed by the attachment of glucose to hemoglobin by a nonenzymatic process, termed glycation. The erythrocyte membrane is permeable to glucose, which enters the cell, where it binds to hemoglobin. The unstable product, termed an aldimine, undergoes an Amadori rearrangement to form a stable …
On the control of microstructure in rapidly solidified Nd–Fe–B alloys through melt treatment

Abstract Rapidly solidified (RS) Nd 2 Fe 14 B alloys were prepared by melt-spinning under different melt treatment conditions i.e., the melt temperature was varied prior to ejection onto the quenching wheel. X-ray diffraction, transmission electron microscopy, thermal analysis and magnetic measurement were conducted on the as-quenched alloys to investigate their structural and magnetic characteristics. RS Nd 2 Fe 14 B alloys may display a variety of microstructures depending upon the thermal history of the melt before ejection: it was possible to synthesize an entirely amorphous structure, a partially amorphous structure containing nuclei and/or nanophases and a nanocrystalline structure. The relationship between the formation of crystalline nuclei or nanophases and the thermal history of the melt was studied. A lower melt ejection temperature produced a nanocrystalline microstructure, while higher melt ejection temperatures ( T >1723 K) largely eliminated the presence of nuclei and associated nanophases and produced an amorphous product. The experimental results indicated that optimization of the melt treatment conditions will produce rapidly solidified Nd–Fe–B alloys with a more uniform microstructure.
Structure-Based Kinetic Models of Modular Signaling Protein Function: Focus on Shp2

We present here a computational, rule-based model to study the function of the SH2 domain-containing protein tyrosine phosphatase, Shp2, in intracellular signal transduction. The two SH2 domains of Shp2 differentially regulate the enzymatic activity by a well-characterized mechanism, but they also affect the targeting of Shp2 to signaling receptors in cells. Our kinetic model integrates these potentially competing effects by considering the intra- and intermolecular interactions of the Shp2 SH2 domains and catalytic site as well as the effect of Shp2 phosphorylation. Even for the isolated Shp2/receptor system, which may seem simple by certain standards, we find that the network of possible binding and phosphorylation states is composed of over 1000 members. To our knowledge, this is the first kinetic model to fully consider the modular, multifunctional structure of a signaling protein, and the computational approach should be generally applicable to other complex intermolecular interactions.
Interband scattering effects on secondary ionization coefficients in GaAs

Abstract The ionization rates of holes and electrons in GaAs were measured experimentally over a wide doping range covering field values from 2.2×10 5 V/cm to 4.7×10 5 V/cm. As opposed to most experimemental measurements in GaAs, no assumption of equal ionization rates of the two carriers has been made. By using the conventional theoretical relationship between carrier ionization coefficients and multiplication data, the effective α is observed to be larger than β in lightly doped diodes while β is larger than α in heavily doped diodes. Previous theories of ionization rates utilizing just the normal conduction and valence bands do not show any possibility of such a crossover. It is suggested that electron transitions to higher conduction bands, which effectively increase the equilibration time of the electron distribution function, offer a resolution of this difficulty. The dependence of the effective electron ionization rate on doping can be explained by the requirement that electrons must make an interband transition before reaching the ionization threshold energy. This interband transition time estimated by this experiment is of the order of 10 −13 sec and is comparable to the transit time of electrons in the avalanching region. The breakdown voltages extrapolated from the measured α and β are consistent with those observed experimentally.
General-purpose blade infrastructure for configurable system architectures

Bladed servers are increasingly being adopted in high-density enterprise datacenters by virtue of the improved benefits they offer in form factor density, modularity, and more robust management for control and maintenance with respect to rack-optimized servers. In the future, such servers are likely to form the key foundational blocks for a variety of system architectures in data centers. However, designing a commodity blade system environment that can serve as a general-purpose infrastructure platform for a wide variety of future system architectures poses several challenges. This paper discusses these challenges and presents specific system architecture solutions, along with application examples to illustrate the general-purpose nature of the infrastructure for parallel and distributed applications.
Restricted multinomial maximum likelihood estimation based upon Fenchel duality

Abstract A commonly occurring problem is that of maximizing a multinomial likelihood over a restricted region. We show that if the region is convex, then a dual problem always exists which is frequently more tractable. A solution to the dual problem leads directly to a solution for the original problem and conversely. Moreover, the form of the dual problem suggests an iterative algorithm for solving a MLE problem when the constraint region can be written as a finite intersection of ‘nice’ constraint regions. We show that this iterative algorithm is guaranteed to converge to the true solution and give several meaningful examples of the algorithm.
The effect of energy resolution on the extraction of information content from gamma-ray spectra

Abstract Rapid unambiguous identification of illicit radioactive materials is a matter of international concern that has yet to be fully attained. This is particularly true for shielded fissile materials in the presence of background radiation and routinely encountered benign radionuclides. We present a systematic treatment of the effect of detector resolution on the identification of nuclides in simple and complex shielded γ-ray spectra. Case studies of some problematic spectra with 1000 counts suggest that, at moderate count rates, near-unambiguous identification (
Measurement of manganese, zinc and cadmium complexation in seawater using Chelex ion exchange equilibria

Abstract Equilibria between Chelex 100∗ and manganese, zinc and cadmium ions were used to determine the complexation of these trace metals in 36‰ Gulf Stream seawater at 25°C and pH 8.2. The method utilized radiotracers ( 54 Mn, 65 Zn, and 109 Cd) to quantify trace metal adsorption from trace metal-amended seawater and from seawater containing a series of ethylenediaminetetracetate (EDTA)—metal ion buffers. Results were consistent with Chelex adsorption of both trace metal ions and trace metal—EDTA chelates. Equilibrium models fitted to the data were used to establish conditional stability constants for Chelex adsorption of manganese, zinc and cadmium ions and for adsorption of EDTA-chelates. These models also yielded ratios of free metal ions to total dissolved trace metal concentrations in seawater: 10 −0.1 for manganese, 10 −0.2 for zinc, and 10 −1.5 for cadmium. Independent measurements with a cadmium ion-selective electrode also yielded a free: total cadmium ratio of 10 −1.5 .
Magnetic resonance imaging: A cryptic contrast agent

Rare gases provide unique opportunities to examine patients and materials with magnetic resonance imaging. A new entry, krypton, offers interesting properties that could move the field forward.
Effects of flooding, tilting of stems, and ethrel application on growth, stem anatomy, and ethylene production of acer platanoides seedlings

Flooding of soil, tilting of stems, and application of ethrel to stems variously influenced growth, stem anatomy and ethylene production of 12‐month‐old Acer platanoides L. seedlings. Flooding greatly suppressed height growth, stem diameter growth, and the rate of dry weight increase of leaves, stems, and roots, with root growth suppressed most. Flooding also increased bark thickness above the level of submergence, reduced the xylem increment, and stimulated ethylene production of stems and ACC accumulation in the roots. Tilting of stems inhibited height growth somewhat, increased diameter growth and fiber production on the upper side of the leaning stem, increased ethylene production somewhat on both the upper and lower side of the stem, and induced formation of tension wood on the upper side of the stem. Tilting did not affect dry weight increase of leaves, stems, or roots. Application of ethrel to upright stems increased xylem increment around the stem; in tilted, ethrel‐treated seedlings xylem increme...
Intrinsic bistability in the resonant tunneling diode

Abstract Quantum transport in the resonant tunneling diode is modeled here with the Wigner formalism including self-consistent potentials for the first time. The calculated I–V characteristics show an intrinsic bistability in the negative differential conductivity region of the curve. We show that intrinsic bistability results from charge storage and the subsequent shifting of the internal potential of the device. The effect of undoped spacer layers is investigated. The cathode region of the RTD shows a strong depletion and quantization of electrons in a deep triangular potential well if no spacer layer is present. The potential drop in the cathode well reduces the barrier height to ballistic electron injected from the cathode, enhancing the valley current and reducing the peak-valley ratio. A finite relaxation time for the electrons increases the negative resistance, reduces the peak to valley ratio of the current, and causes a ‘soft’ hysteresis in the bistable region. The spacer layer prevents the formation of a deep quantum well at the cathode barrier, and the distribution does not deplete as sharply as without the spacer layer.
VEGF receptors mediate hypoxic remodeling of adult ovine carotid arteries

Recent studies suggest that VEGF contributes to hypoxic remodeling of arterial smooth muscle, although hypoxia produces only transient increases in VEGF that return to normoxic levels despite sustained changes in arterial structure and function. To explore how VEGF might contribute to long-term hypoxic vascular remodeling, this study explores the hypothesis that chronic hypoxia produces sustained increases in smooth muscle VEGF receptor density that mediate long-term vascular effects of hypoxia. Carotid arteries from adult sheep maintained at sea level or altitude (3,820 m) for 110 days were harvested and denuded of endothelium. VEGF levels were similar in chronically hypoxic and normoxic arteries, as determined by immunoblotting. In contrast, VEGF receptor levels were significantly increased by 107% (VEGF-R1) and 156% (VEGF-R2) in hypoxic compared with normoxic arteries. In arteries that were organ cultured 24 h with 3 nM VEGF, VEGF replicated effects of hypoxia on abundances of smooth muscle α actin (SMαA), myosin light chain kinase (MLCK), and MLC20 and the effects of hypoxia on colocalization of MLC20 with SMαA, as measured via confocal microscopy. VEGF did not replicate the effects of chronic hypoxia on colocalization of MLCK with SMαA or MLCK with MLC20, suggesting that VEGF's role in hypoxic remodeling is highly protein specific, particularly for contractile protein organization. VEGF effects in organ culture were inhibited by VEGF receptor blockers vatalinib (240 nM) and dasatinib (6.3 nM). These findings support the hypothesis that long-term upregulation of VEGF receptors help mediate sustained effects of hypoxia on the abundance and colocalization of contractile proteins in arterial smooth muscle.
Bacterial Alginate Control of Enzyme Modification

Deux souches bacteriennes de Pseudomonas aeruginosa sont capables de synthetiser de l'alginate. Des milieux de culture mis en presence de sources de carbone differentes sont testes pour connaitre le taux d'acetylation des alginates, modification chimique a l'origine de changements de proprietes physiques de ce polymere
Analysis of unannotated equine transcripts identified by mRNA sequencing

Sequencing of equine mRNA (RNA-seq) identified 428 putative transcripts which do not map to any previously annotated or predicted horse genes. Most of these encode the equine homologs of known protein-coding genes described in other species, yet the potential exists to identify novel and perhaps equine-specific gene structures. A set of 36 transcripts were prioritized for further study by filtering for levels of expression (depth of RNA-seq read coverage), distance from annotated features in the equine genome, the number of putative exons, and patterns of gene expression between tissues. From these, four were selected for further investigation based on predicted open reading frames of greater than or equal to 50 amino acids and lack of detectable homology to known genes across species. Sanger sequencing of RT-PCR amplicons from additional equine samples confirmed expression and structural annotation of each transcript. Functional predictions were made by conserved domain searches. A single transcript, expressed in the cerebellum, contains a putative kruppel-associated box (KRAB) domain, suggesting a potential function associated with zinc finger proteins and transcriptional regulation. Overall levels of conserved synteny and sequence conservation across a 1MB region surrounding each transcript were approximately 73% compared to the human, canine, and bovine genomes; however, the four loci display some areas of low conservation and sequence inversion in regions that immediately flank these previously unannotated equine transcripts. Taken together, the evidence suggests that these four transcripts are likely to be equine-specific.
Cosmological BCS mechanism and the big bang singularity

We provide a novel mechanism that resolves the big bang singularity present in Friedman-Lemaitre-Robertson-Walker space-times without the need for ghost fields. Building on the fact that a four-fermion interaction arises in general relativity when fermions are covariantly coupled, we show that at early times the decrease in scale factor enhances the correlation between pairs of fermions. This enhancement leads to a BCS-like condensation of the fermions and opens a gap dynamically driving the Hubble parameter H to zero and results in a nonsingular bounce, at least in some special cases.
Receptive field properties of the macaque second somatosensory cortex: evidence for multiple functional representations.

The detailed functional organization of the macaque second somatosensory cortex (SII) is not well understood. Here we report the results of a study of the functional organization of the SII hand region that combines microelectrode mapping using hand-held stimuli with single-unit recordings using a motorized, computer-controlled tactile oriented bar. The data indicate that the SII hand region extends ∼10 mm in the anteroposterior (AP) dimension, primarily within the upper bank of the lateral sulcus. Furthermore, we find evidence that this region consists of multiple functional fields, with a central field containing neurons that are driven well by cutaneous stimuli, flanked by an anterior field and a posterior field that each contain neurons that are driven well by proprioceptive stimuli and less well by cutaneous stimuli. The anterior field extends ∼4-5 mm AP, the central field extends ∼3-4 mm, and the posterior field extends ∼3 mm. Data from the motorized stimulator indicate that neurons in the central field are more responsive to oriented bars, more frequently exhibit orientation tuning, and have larger receptive fields than neurons in the anterior and posterior fields. We speculate that the three putative fields play different functional roles in tactile perception; the anterior and posterior fields process information that involves both proprioceptive and cutaneous input such as sensorimotor integration or stereognosis, whereas the central field processes primarily cutaneous information.
The Influence of Local Bedrock: An Important Consideration in the Interpretation of Textural and Mineralogic Analyses of Till

ABSTRACT Bedrock produces variations in texture and composition of tills not only on a regional scale but also on a local one. Bedrock influence is evident in Wisconsinan tills in an area as small as a township in the Allegheny Plateau of northeastern Ohio. Generally till sheets of the Plateau fine upward with decreasing age. Within the Mogadore and Northampton tills, samples from borings terminating in sandstone bedrock on the upland contain significantly more sand and have higher quartz-feldspar ratios than those from the same tills overlying lacustrine silts and clays in the valley. On the upland samples from the Northampton till, overlying sandstone contains slightly more sand than that from the same till overlying shale and siltstone. However, quartz-feldspar ratios increase down ice from sandstone bedrock highs. A few kilometers of transport may have been required for ice to crush plucked sandstone fragments which added more quartz to the fine sand fraction of the Northampton till. Geologists mapping tills using soil associations should be aware of textural and lithological variations produced by local bedrock.
Low-temperature magnetic-elastic anomalies in fcc Fe-Cr-Ni alloys

Abstract Using ultrasonic methods, we measured the complete elastic constants of several polycrystalline face-centered-cubic Fe-Cr-Ni alloys at low temperatures: 4−295 K. The alloys represent nine interstitial (carbon-plus-nitrogen) compositions. We also measured dc magnetic susceptibility. Upon cooling, a paramagnetic-antiferromagnetic (Neel) phase transition occurs. The Neel transition temperature depends strongly on interstitial content. We fit both composition and temperature effects to Ducastelle's 3d-electron model, which contains two terms, band-structure and repulsive energies.
Critical care nursing education at the baccalaureate level: study of employment and job satisfaction.

Objective To examine the employment patterns of nurses who completed an undergraduate course in critical care nursing (CCN); examine the impact of the course on job satisfaction; and compare the job satisfaction of critical care nurses who completed a course at the baccalaureate level and a control group of nurses in critical care who did not have these educational experiences. Design: Descriptive. Setting: Ten hospitals in the midwest in which graduates of a CCN course at the BSN level were in practice. Subjects: There were two groups of participants: 42 nurses prepared at the undergraduate level for critical care and 59 critical care nurses from the same units. Outcome Measures: Employment patterns and job satisfaction measured by Stamps and Piedmonte's Index of Work Satisfaction instrument. Results: Most ( n =33, 78.6%) graduates entered critical care as their first position in nursing. At the time of follow-up, these graduates remained in CCN practice. The findings suggested that completion of an undergraduate course enabled students to enter critical care as new graduates. Results of a Mann-Whitney U test indicated no differences in job satisfaction between nurses who remained in critical care and those practicing in non-critical care units. There were no significant differences in total job satisfaction or in any of its component scores between graduates of the course and the control group of critical care nurses. Both groups were least satisfied with pay and most satisfied with their interactions with others on the unit. Conclusions: Although educational experiences in critical care at the undergraduate level did not influence job satisfaction, other benefits of this education were suggested by the findings. Completion of an undergraduate CCN course enabled graduates to enter critical care as their first practice position.
Autoradiographic evaluation of circadian periodicity in cell proliferation in the periodontal ligament of the young mouse

Five-week-old BNL male mice were maintained on a 12-h light/dark cycle, subcutaneously injected with [3H]-thymidine 1 h before death and killed every 3 h for 24 h. Autoradiographs were made from demineralized, paraffin-wax embedded sagittal sections of maxillae. The labelling index was calculated for fibroblast-like cells of the periodontal ligament mesial to the first molar. A bimodal distribution of labelled cells was seen. Labelling index was highest at 0900 h (light period); a second, lower, peak was seen at 2400 h (dark period). Cell proliferation was significantly increased during the light period. The increased activity during the dark period may represent a superimposed secondary, ultradian, rhythm, differences in periodontal cell subtypes or may be related to the feeding and activity cycle of the mouse. Thus there is a 24-h cyclic rhythmicity in the proliferation of periodontal-ligament cells in the mouse.
Mechanism of Crystallization of Hydrocortisone by Ultrasonic Irradiation

Reproducible, reduced crystal size distributions resulted from insonating a supersaturated solution, whose background particle count is controlled, at a fixed temperature. The crystallization temperature of the insonated and uninsonated samples was dependent on the number of heterogeneous nuclei present. The ultrasonic energy used in this study was in excess of the amount required to reduce the particle size. Ultrasound acted in the initial phase of crystallization. Ultrasound is believed to act by eroding, shattering, or in some way disrupting nuclei that form in a normal manner.
The relationship of the zone of polarizing activity to supernumerary limb formation (twinning) in the chick wing bud

Abstract The role of the polarizing zone mesoderm in development of supernumerary distal wing parts after 180° rotation of the wing tip was investigated. Postaxial mesoderm with and without polarizing tissue was repositioned preaxially in the wing bud and duplications occurred only when polarizing zone tissue was included. When the polarizing zone was removed and the distal tip of the wing reoriented, no duplication resulted. Similarly when the polarizing zone was removed, the distal tip reoriented and postaxial, nonpolarizing mesoderm introduced to restore the tissue mass of the stump, no twinning occurred. However, with the distal aspect reoriented on a stump from which postaxial, nonpolarizing mesoderm was removed, twinning occurred in 92.9% of the cases. Further, when the polarizing zone was removed, the distal aspect reoriented and a small piece of polarizing tissue returned, twinning resulted in 93.5% of the cases. These results indicate that polarizing zone tissue is required for the twinning that results after 180° rotation of the wing tip.