cssi/SciSciGPT-SciSciNet huggingface dataset:
Protein Dynamics and the Time Domain

Proteins are dynamic systems which exhibit a wide spectrum of motions. During the last several years it has been realized that protein motions are essential to their function [1–5]. It has also become clear that motions and functional processes in proteins span an enormous range of time scales from the subnanosecond to more than a kilosecond [6,7]. Thus proteins are superb systems for exploring the dynamic relations between structure and function in the time domain.
Interaction between Seed Detectability and Seed Preference Affects Harvest Rates of Granivorous Rodents

Granivorous rodents commonly exhibit preferences for seeds of particular plant species. However, among buried seeds that are available, rodents may find that alternate, less desirable seeds are more easily located by olfaction than preferred seeds. Seeds of Indian ricegrass (Achnatherum hymenoides) are a highly preferred food resource for seed-caching desert heteromyid rodents. We tested relative abilities of heteromyids to locate buried caches of Indian ricegrass seeds versus seeds of another plant species (cheatgrass, Bromus tectorum) that are common in heteromyid diets at a western Nevada field site. Rodents located more cheatgrass than Indian ricegrass seed caches in the field when seeds were unaltered. When ground, however, detectability of preferred Indian ricegrass seeds increased, presumably due to release of volatile compounds inside seeds, and more ground Indian ricegrass seed caches were found and removed compared with ground cheatgrass caches. Grinding cheatgrass seeds did not affect harvest rates of cheatgrass caches. Results of a laboratory cache removal experiment using 2 heteromyid species, Merriam's kangaroo rats (Dipodomys merriami) and long-tailed pocket mice (Chaetodipus formosus), mirrored field cache removal results. Dispersal of Indian ricegrass seeds and establishment of new seedlings occurs largely through emergence of seedlings from heteromyid scatterhoard caches. Our results suggest that Indian ricegrass seeds may have been selected for reduced olfactory detectability to minimize the probability that they are recovered by rodents for later consumption once they have been cached.
Current and Emerging Evidence for Toll-Like Receptor Activation in Sjögren's Syndrome.

While the importance of Toll-like receptor (TLR) signaling is well established in many autoimmune diseases, the role of TLR activation in Sjogren's syndrome (SS) is poorly understood. Studies in mice and humans reveal that TLRs are potent mediators of inflammation in SS. TLRs are expressed and functional in salivary tissue, and TLRs in peripheral blood cells of SS patients are also upregulated and hyperresponsive to ligation. In this review, we will detail observations in mouse models regarding the importance of TLR activation in both local and systemic disease. We will then discuss studies in SS patients that provide evidence of the importance of TLR-mediated signaling in disease. While the ligands that activate TLRs in the context of SS are unknown, emerging data suggest that damage-associated molecular patterns (DAMPs) may be significant drivers of the chronic and unremitting inflammation that is characteristic of SS. We will discuss putative DAMPs that may be of clinical significance in disease. Therapies that target TLR signaling cascades will likely reduce both exocrine-specific and systemic manifestations of SS.
First high temperature safety tests of AGR-1 TRISO fuel with the Fuel Accident Condition Simulator (FACS) furnace

Abstract Three TRISO fuel compacts from the AGR-1 irradiation experiment were subjected to safety tests at 1600 and 1800 °C for approximately 300 h to evaluate the fission product retention characteristics. Silver behavior was dominated by rapid release of an appreciable fraction of the compact inventory (3–34%) at the beginning of the tests, believed to be from inventory residing in the compact matrix and outer pyrocarbon (OPyC) prior to the safety test. Measurable release of silver from intact particles appears to become apparent only after ∼60 h at 1800 °C. The release rate for europium and strontium was nearly constant for 300 h at 1600 °C (reaching maximum values of approximately 2 × 10 −3 and 8 × 10 −4 respectively), and at this temperature the release may be mostly limited to inventory in the compact matrix and OPyC prior to the safety test. The release rate for both elements increased after approximately 120 h at 1800 °C, possibly indicating additional measurable release through the intact particle coatings. Cesium fractional release from particles with intact coatings was −6 after 300 h at 1600 °C or 100 h at 1800 °C, but release from the rare particles that experienced SiC failure during the test could be significant. However, Kr release was still very low for 300 h 1600 °C ( −6 ). At 1800 °C, krypton release increased noticeably after SiC failure, reflecting transport through the intact outer pyrocarbon layer. Nonetheless, the krypton and cesium release fractions remained less than approximately 10 −3 after 277 h at 1800 °C.
Weakly saturated random graphs

A graph $G$ is weakly $H$-saturated if the complete graph is obtained by iteratively completing copies of $H$ minus an edge. We identify the threshold $p_c$ at which the Erdős-Renyi graph ${\mathcal G}_{n,p}$ is likely to be weakly $H$-saturated, for all $H$ such that $H\setminus e$ is 2-balanced for every edge $e\in H$. The threshold is sharp if this holds strictly. We also establish a general asymptotic lower bound for $p_c$, which holds for all graphs $H$, and is sharp in many cases. Our results apply for instance when $H=K_r$, solving a problem of Balogh, Bollobas and Morris.
E-120 The utility of repeat computed tomography angiogram after blunt cerebrovascular injury

Introduction Blunt cerebrovascular injury (BCVI) can lead to thromboembolic events. The necessity of short-term repeat vascular imaging after the initial diagnosis is controversial. The aim of this retrospective cohort study is to assess the utility of short-interval computed tomography angiography (CTA) after an initial diagnosis of BCVI. Methods We retrospectively reviewed consecutive patients with BCVI managed at the University of Louisville from 2016–2019 who underwent short-term (1–3 weeks) repeat CTA after initial diagnosis. The exclusion criteria were age Results The study cohort comprised 38 patients (68% male) with a mean age of 45 years. Motor vehicle accident (79%) was the most common mechanism of injury, and 89% had cervical spine fractures. Unilateral VA and grade I dissection were the most common findings on initial CTA were a unilateral VA dissection (66%) that was Biffl grade I (36%). Antiplatelet therapy or anticoagulation was administered to 82% of patients after the initial diagnosis (table 1). Shift analysis showed a significant improvement in Biffl grades on repeat CTA (p=0.0001) (figure 1). Biffl grades I injuries were more likely to improve (relative risk ratio [RRR]=3.6, CI 95% (1.02–13.1),p=0.04), whereas grade IV injuries were more likely to be stable (RRR=33, CI 95% (2.9–374), p=0.005). Ten BCVIs (26%) completely resolved on repeat imaging (table 2). The rates of early ( Conclusion Short-term repeat non-invasive vascular imaging can help to identify the evolution of BCVI. Repeat vascular imaging at short intervals can help to identify patients who may require endovascular intervention, but additional studies are necessary to clarify its role in the management of BCVI. Disclosures Z. Aljuboori: None. K. Meyer: None. R. James: None. D. Ding: None.
Robust nanofibrillated cellulose composite SERS substrate for capillary preconcentration and trace level detection of organic molecules

Preconcentration of organic analytes from an aqueous solution onto a substrate surface can significantly improve trace level analyte detection by Raman spectroscopy. Nanofibrillated cellulose (NFC)-based three dimensional (3D) substrates have great potential for this application since they can readily absorb water when exposed to an aqueous analyte solution while adsorbing organic molecules from the solution. However, the transport of organic analytes inside the substrate along with water, loss of mechanical robustness, and disintegration of the 3D structure in water limit the use of porous NFC substrates in aqueous environments. To overcome these deficiencies, a chemically crosslinked network of methacrylated carboxymethyl cellulose was incorporated into the NFC matrices, which improves the stability and robustness of the substrates in water. Application of a polydimethyl siloxane-based hydrophobic coating on four of the five analyte exposed surfaces further improves preconcentration efficiency by forcing the analyte solutions to pass through one hydrophilic surface only. Samples with a range of porosities were investigated to optimize sampling time, solution uptake volume, and substrate robustness in water. Using this substrate, parts-per-million detection sensitivity for organic probe molecules in aqueous solution was possible. Incorporation of silver nanoparticles within the substrates further enhanced substrate sensitivity to parts-per-trillion level detection of probe molecules, due to the Raman signal enhancement by surface enhanced Raman scattering (SERS) effect. A model is presented here which describes the linearity, saturation, and depletion of the SERS signal.
Digital Home Assistants and Aging: Initial Perspectives from Novice Older Adult Users

Digital home assistants like the Amazon Echo are increasing in popularity each year among the general population and provide assistance across a wide array of daily activities. Despite their genera...
A Novel Robotic System for Ultrasound-guided Peripheral Vascular Localization

In this paper, we present an autonomous RGB-D and 2D ultrasound-guided robotic system for collecting 3D localized volumes of peripheral vessels. This compact design, with available commercial components, lends itself to platform utility throughout the human body. The fully integrated system works with force limits for future safety in human use. We propose a PID force controller for smooth and safe robot scanning following a priori 3D trajectory generated from a surface point cloud. System calibration is implemented to determine transformations among sensors, end-effector and robot base. A vascular localization pipeline that consists of detection and tracking is proposed to find the 3D vessel positions in real-time. Precision tests are performed with both predesignated and autonomously selected areas in an arm phantom. The average variance of the autonomously collected ultrasound images (to construct 3D volumes) between repeated tests is shown to be around 0.3 mm, similar to the theoretical spatial resolution a clinical ultrasound system. This fully integrated system demonstrates the capability of autonomous collection of peripheral vessels with built-in safety measures for future human testing.
Racialized customer service in restaurants: A quantitative assessment of the statistical discrimination explanatory framework

Despite popular claims that racism and discrimination are no longer salient issues in contemporary society, racial minorities continue to experience disparate treatment in everyday public interactions. The context of full-service restaurants is one such public setting wherein racial minority patrons, African Americans in particular, encounter racial prejudices and discriminate treatment. To further understand the causes of such discriminate treatment within the restaurant context, this article analyzes primary survey data derived from a community sample of servers (N = 200) to assess the explanatory power of one posited explanation—statistical discrimination. Taken as a whole, findings suggest that while a statistical discrimination framework toward understanding variability in servers’ discriminatory behaviors should not be disregarded, the framework’s explanatory utility is limited. Servers’ inferences about the potential profitability of waiting on customers across racial groups explain little of the overall variation in subjects’ self-reported discriminatory behaviors, thus suggesting that other factors not explored in this research are clearly operating and should be the focus of future inquires.
Focus formation by a murine sarcoma-leukemia virus complex. II. Quantitative aspects of the interaction between radiation leukemia virus and its murine sarcoma virus pseudotype in strain c57bl mouse embryo cells.

A quantitative study has been made of the interactions between radiation leukemia virus (RadLV), its murine sarcoma virus pseudotype, and their C57BL host cells. The elimination of interference phenomena by delayed infection of cells with RadLV made possible the quantitative determination of the pseudotype in terms of defective sarcoma and endogenous RadLV particles. This in turn permitted the quantitative assessment of RadLV helper activity and of the various factors which influence the accuracy and sensitivity of the helper assay.
Polymer Derived Nicalon/Si‐C‐O Composites: Processing and Mechanical Behavior

Ceramic matrix composites fabricated using Nicalon fiber and several polysilsesquioxane-derived Si-C-O matrices were characterized by optical and SEM and in four-point bending. In the matrix material linear shrinkages of up to 19 percent were observed for the vinylmethyl copolymer pyrolyzed to 1200 C, and up to 13 percent for the phenylmethyl material pyrolyzed to the same temperature, resulting in considerable matrix cracking. Under four-point loading, most composite samples fractured in a brittle manner as the result of strong fiber-matrix bonding. Flexural strengths, moduli, and ultimate strain varied with fiber sizing and processing parameters. Testing and analysis is being applied to promote more fibrous pullout during fracture.
Facebook: Perils, Perceptions and Precautions.

Facebook is one of the fastest growing applications of the Internet. Social networking via Facebook provides a popular way for students and others to connect with a wide audience and expand their circle of friends. Facebook account holders have been denied admission to universities, not hired for jobs, lost scholarships, been disciplined by college administrators and arrested for online postings and exercising what they consider to be their right of free speech. A survey of 118 undergraduate students and 45 employers was conducted in an effort to determine their Facebook habits and perceptions about proper postings. Recent cases involving disciplinary action, restrictions on Facebook use and the First Amendment are discussed. Suggestions are made for safer Facebook protocol.
Complement Factor H-Binding Protein, a Putative Virulence Determinant of Borrelia hermsii, Is an Antigenic Target for Protective B1b Lymphocytes

Vaccination is the most effective way to control infectious diseases. A variety of microbial pathogens use antigenic variation, an immune evasion strategy that poses a challenge for vaccine development. To understand protective immune responses against such pathogens, we have been studying Borrelia hermsii, a bacterium that causes recurrent bacteremia due to antigenic variation. An IgM response is necessary and sufficient to control B. hermsii infection. We have recently found a selective expansion of B1b cells concurrent with the resolution of B. hermsii bacteremia. B1b cells from convalescent but not naive mice confer long-lasting immunity, but the Ag(s) driving the protective IgM responses is unknown. Herein we demonstrate that convalescent B1b cell-derived IgM recognizes complement factor H-binding protein (FhbA), a B. hermsii outer-surface protein and putative virulence factor that does not undergo antigenic variation and is expressed by all clinical isolates. A progressive increase in the IgM response to FhbA correlated with the kinetics of B1b cell expansion, diminished the severity of bacteremic episodes, and led to the eventual resolution of the infection. These data indicate that FhbA is a specific target for protective B1b cell responses. Ags recognized by B1b cells may be considered as an important component in vaccination strategies.
On the origin of substance P and glutamic acid decarboxylase (GAD) in the substantia nigra

Knife cuts in the frontal plane separating the anterior part of the caudate-putamen from the globus pallidus resulted in marked decreases in substances P levels in the reticular part of the substantia nigra. More caudal knife cuts were required in order to effect maximal decreases in nigral glutamic acid decarboxylase levels. Thus, there is a clear anatomical dissociation between the striatal neurons which project to the reticular part of the substantia nigra and which contain SP, and the more caudally located GAD-containing striatal and pallidal neurons, all of which travel through the globus pallidus on their way to the substantia nigra.
Subcriticality for transport of multiplying particles in a slab

A commonly used method for theoretically establishing subcriticality of a given physical system is to show that the corresponding time-independent linear integral transport equation has a nonnegative solution for any nonnegative inhomogeneous term. Olhoeft [l] used this approach to establish subcriticality for the physically obvious case of nonmultiplying transport (see Section 2 for precise definition of terms). Case and Zweifel [2] extended this result to permit the possibility of multiplying particles, provided the underlying region has a finite optical diameter. The latter restriction excludes the computationally important case of transport in a slab. Keller [3] used this method to establish a subcriticality theorem which permits the possibility of multiplying transport in a slab of finite thickness, but is restricted to monoenergetic transport with isotropic distribution of secondary particles. Our aim here is to apply this method to establish subcriticality theorems for multiplying transport of variable ennergy particles in a slab of finite thickness, with a general law of distribution of secondary particles. The basic definitions and notation are given in Section 2. Some preliminary propositions are collected in Section 3. An immediate corollary of these propositions is the above-mentioned theorem of Olhoeft in its restriction to slab geometry. The objective in Section 4 is to show that existence of a nonnegative solution of the integral transport equation for every nonnegative inhomogeneous term is equivalent to uniform convergence of the Neumann series of the integral transport operator. In Section 5 we use this equivalence
Aquaculture in bio-regenerative life support systems (BLSS): Considerations

Abstract A significant amount of research has been invested into understanding the effects of including fish culture in bio-regenerative life support systems (BLSS) for long duration space habitation. While the benefits of fish culture as a sub-process for waste treatment and food production continue to be identified, other pressing issues arise that affect the overall equivalent system mass associated with fish culture in a BLSS. This paper is meant to provide insight into several issues affecting fish culture in a BLSS that will require attention in the future if fish meant for consumption are to be cultured in a BLSS.
Decreased sensitivity of an interferon-resistant subline of murine leukemia L-1210 cells to toxic effects of ricin and abrin.

Abstract Approximately two to four times higher concentrations of the plant toxins abrin and ricin are required to inhibit protein synthesis in interferon-resistant L-1210R cells to the same degree as in interferon-sensitive L-1210S cells. However, amounts of interferon 10-fold higher than those required for protection from viral infection fail to show any effect on ricin intoxication of L-1210S cells.
Acute effect of nicotine on auditory gating in smokers and non-smokers

This paper investigates the role of cholinergic mechanisms in auditory gating by assessing the acute effects of nicotine, an acetylcholinomimetic drug, on behavioral and electrophysiological measures of consonant-vowel (CV) discrimination in quiet and in broadband noise (BBN). In a single-blind procedure, categorical boundaries and mismatch negativity (MMN) in two conditions (quiet, BBN) were obtained from 10 non-smokers and 4 smokers with normal hearing under two drug conditions (nicotine, placebo). After the nicotine sessions, plasma tests revealed a subject's nicotine concentration and subjects reported any symptoms. Larger MMN areas and steeper slopes at the boundary were interpreted as reflecting better electrophysiological and behavioral CV discrimination, respectively. Results indicate that, in non-smokers, the effects of nicotine on electrophysiological CV discrimination in quiet increase with an increase in severity of symptoms. Specifically, asymptomatic non-smokers (N = 5) demonstrate little improvement (and sometimes decrements) in performance while symptomatic non-smokers (N = 5) exhibit nicotine-enhanced discrimination, as do smokers. In noise, all subjects demonstrate nicotine-enhanced behavioral and electrophysiological discrimination. Additionally, in noise, smokers exhibit a larger number of measurable categorical boundaries as well as larger MMN areas than non-smokers in both placebo and nicotine sessions. Results are consistent with the hypothesis that nicotinic cholinergic mechanisms play a role in the gating of auditory stimuli.
Cleavage of the Carbon−Sulfur Bonds in Thiophenes by a Binuclear Ruthenium Complex

The dinuclear polyhydride [Cp*RuH2]2 (Cp* = C5Me5) reacts with thiophene at ambient temperature to give a C−S ring-opened “flyover” complex in which all atoms are bound to the metal centers. A simi...
QUALITY AND COMPOSITIONAL CHARACTERISTICS OF STABILIZED, UNSTABILIZED, AND IMITATION PEANUT BUTTER

Commercial stabilized, unstabilized (“organic”), and imitation peanut butters were analyzed for differences in moisture, protein and oil content, Gardner color values, sensory quality attributes and price. Comparisons were made by manufacturer (national, chain store, or “other”) and by form (smooth or crunchy). Stabilized and unstablized peanut butters were significantly higher in protein and oil content than imitation brands. Stabilized brands were rated significantly higher in texture and flavor quality than unstabilized or imitation types. Unstabilized butters were highest in price but rated poorest in quality. Stabilized products were intermediate in price while imitation butters were lowest. There were no significant differences in protein and fat content of national, chain store and “other” brands either in the smooth or crunchy form. In the smooth butters, the color quality, textural attributes, and prices of national brands were significantly higher than chain store or “other” brands. In the crunchy form, where only national and chain store brands could be compared, national brands were rated significantly higher in color and flavor qualities than chain store brands; prices, however, were not significantly different.
Mechanisms of increased venous smooth muscle tone in desoxycorticosterone acetate-salt hypertension

The purpose of the present study was to identify mechanisms that contribute to increased venous smooth muscle tone in desoxycorticosterone acetate (DOCA)-salt hypertension in rats. Male Sprague-Dawley rats were uninephrectomized, received subcutaneous implants of DOCA, and drank 1% sodium chloride/0.2% potassium chloride solutions. Sham-operated rats received only uninephrectomy and drank tap water. Three to 4 weeks later, arterial and venous catheters were implanted for measurements of arterial and central venous pressures, respectively, and a silicone balloon catheter was permanently fixed in the right atrium to produce brief circulatory arrest. Venous smooth muscle activity was estimated on the basis of repeated measurements of mean circulatory filling pressure in conscious rats resting in their home cages. DOCA-salt-treated rats were hypertensive and had elevated mean circulatory filling pressure compared with normotensive sham-operated rats. Blockade of the endothelin subtype A receptor with 1 mg/kg ABT-627 IV decreased arterial blood pressure and mean circulatory filling pressure significantly more in hypertensive rats than in normotensive rats. Ganglionic blockade with 30 mg/kg hexamethonium IV also decreased arterial blood pressure and mean circulatory filling pressure more in hypertensive than in normotensive rats. Pretreatment with ABT-627 did not affect subsequent hemodynamic responses to ganglionic blockade. We conclude that venous smooth muscle tone is increased in DOCA-salt hypertension through the independent actions of both endogenous endothelin-1 acting on subtype A receptors and sympathetically mediated venoconstrictor activity.
An immune hemagglutination procedure with very high sensitivity applied to the detection of hepatitis B antibody and antigen and immune complex.

. An immune agglutination procedure is described in which red cells are coated with antigen and agglutination is observed after a short incubation with antibody in reagent serum. Conversely, the cells may be coated with antibody and used to test for the presence of antigen. Treatment of the reagent serum with cobra venom factor results in inhibition, and there is a marked loss of sensitivity with cells pretreated with formalin or chromic chloride, suggesting that C3 and some type of reactive sites on the cells are required. The distinctive features of the new procedure are that incubation time is very short, sensitivity is several orders of magnitude higher than with other related tests, and, within some limitations, bovine (steer) red cells with bovine serum can be used as an alternative to human red cells with human serum. It is necessary to remove an inhibitor from the reagent serum, human or steer. While the mechanism of the procedure needs further elucidation, the findings reported here suggest that it ought to be sufficiently sensitive to detect hepatitis B antigen if present in virtually any blood sample. With appropriate modifications it should be useful for blood donor screening, diagnosis, and for studying many other antigen-antibody systems.
Broad spectrum of in vivo forward mutations, hypermutations, and mutational hotspots in a retroviral shuttle vector after a single replication cycle: deletions and deletions with insertions.

Abstract In the preceding paper we described an experiment that determined the in vivo forward mutation rate in a single replication cycle for spleen necrosis virus. In addition to substitutions, frameshifts, and hypermutations, the mutated proviruses contained two classes of deletions. One class of deletions contained short direct repeats at the deletion junctions. Another class of deletions had short stretches of sequences inserted at the deletion junctions. In this report, we describe the deletion mutations, and we present models for their generation. Detailed analysis of two deletions with insertions indicates that these mutations occurred as a result of template switching during plus-strand DNA synthesis. The analysis also indicates that fragments of viral RNA generated by the viral RNase H endonuclease are used as templates and contribute to the sequences inserted at the deletion junctions.
Production of pyrazine derivatives in the radiolysis of aqueous solutions of the cyclic dipeptides.

RADIATION-INDUCED reactions in aqueous solutions of amino-acids, peptides, and related compounds have been treated in a number of reports from this Laboratory1. In connexion with this work, we have had occasion to examine the effects of γ-irradiation on the ultra-violet absorption spectra of solutions of various simple peptides. The measurements reveal that solutions of the cyclic dipeptides under specific conditions exhibit pronounced and characteristic post-irradiation changes. If, for example, an oxygen-free solution of alanine anhydride is irradiated and examined spectrophotometrically, the differential spectrum (read against unirradiated solution) shows negligible absorption above 2600 A. so long as the solution is not exposed to the atmosphere. However, if oxygen is introduced, an absorption maximum in the longer wave-length region slowly appears. This post-irradiation change is accelerated by addition of either acid or base. In neutral and basic solution the absorption maximum is at about 320 mµ ; in acid solution the maximum shifts to 340 mµ. This shift is reversible, and the evidence is that the final yield of the absorbing species is essentially independent of the pH of the solution during the post-irradiation oxidation. Solutions of glycine anhydride exhibit quite similar properties except that the wavelength of maximum absorption (320 mµ) is independent of pH. It is also to be noted that these post-irradiation changes are not observed if oxygen is present during irradiation.
Comparison of wall-coated and packed-bed reactors for steam reforming of methanol

Abstract The kinetics of methanol steam reforming on a commercial CuO/ZnO/Al2O3 catalyst in packed-bed and wall-coated microreactors were compared experimentally. Different dimensions of both reactor configurations were tested and the transport limitations were analyzed using 2D reactor models. Packed-bed reactors of dimensions from 4.1 down to 1 mm i.d. were found to be heat transfer limited and temperature gradients of up to 40 K could exist in the bed. The reactor diameter required to eliminate temperature gradients was estimated to be 300 μ m, which clearly is not practical. On the other hand, the wall-coated reactor was found to be free from any mass or heat transfer limitations in dimensions from 4.1 mm down to 200 μ m i.d. Our modeling results showed that the reactor volumetric productivity increases with thicker catalyst wall-coatings for the same reactor diameter. We also show that the wall-coated reactor offers a better solution to achieve low pressure drop and high catalyst activity compared to a packed-bed microreactor.
Experimental evidence that changes in oocyte growth influence meiotic chromosome segregation

Background It is well known that the fidelity of meiotic chromosome segregation is greatly reduced with increasing maternal age in humans. More recently, direct studies of human oocytes have demonstrated a striking age-related increase in oocytes exhibiting gross disturbances in chromosome alignment on the meiotic spindle. This abnormality, termed congression failure, has been postulated to be causally related to human non-disjunction and to result from subtle alterations in folliculogenesis that develop with advancing reproductive age. Methods Immunofluorescence staining, conventional cytogenetic analysis and spectral karyotyping of oocytes from mouse models were used to investigate the hypothesis that changes in the regulation of folliculogenesis induce meiotic defects. Results Mutations that affect oocyte growth were found to increase the frequency of congression failure at first meiotic metaphase. Importantly, increased congression failure was correlated with meiotic non-disjunction, suggesting a cause-and-effect relationship. Conclusions Our findings support the hypothesis that congression failure results from disturbances in the complex interplay of signals regulating folliculogenesis and that these changes subtly alter the late stages of oocyte growth, increasing the risk of a non-disjunction error. These findings have important implications for human aneuploidy, since they suggest that it may be possible to develop prophylactic treatments for reducing the risk of age-related aneuploidy.
Is the Structure of Affect Similar for Younger and Older Children? Cross-Sectional Differences in Negative and Positive Affectivity

Although studies investigating the validity of positive affectivity and negative affectivity in children have been supportive, investigations of changes in the structure of affect across childhood ...
Food Safety From Farm To Table

Abstract The American food supply is among the safest in the world. However, millions of Americans become ill from food-borne bacteria, viruses and parasites each year. Some of these microorganisms include; E. Coli 0157:H7, Salmonella, Staphylococcus, Cyclospora, Listeria, Cryptosporidium, and viral Hepatitis A. Nine thousand of our most vulnerable citizens, namely very young children and the elderly, die every year as a result of microbiological contamination of the food they consume. The goal of the President's Food Safety Initiative is to reduce, to the greatest extent possible, the incidence of food borne illness. This goal will be accomplished through a series of seven initiatives: expansion of the food safety surveillance system, improved coordination between Federal, State and local health authorities, increased inspections, risk assessment, research, consumer education and strategic planning. This is an interagency undertaking which will involve coordinating the efforts of six federal agencies: two agencies under the Department of Health and Human Services–the Food and Drug Administration, the Centers for Disease Control and Prevention; and three agencies under the Department of Agriculture–the Agricultural Research Service, the Food Safety and Inspection Service and the Cooperative State Research, Education, and Extension Service; and the Environmental Protection Agency. This poster session will highlight the seven areas of the food safety initiative and how they impact public health and the work of administrative and public health dietitians.
An in vivo study of intracytoplasmic membranous structures associated with chronic stunt virus infection in granular hemocytes of Amyelois transitella.

The fine structure of cytoplasmic, membranous structures associated with chronic stunt virus infection was studied in granular hemocytes of larvae of Amyelois transitella. Although nuclei of infected hemocytes apparently were not affected, viroplasmic bodies, the assumed sites of viral assembly, often filled the cytoplasm of these cells. Early stage viroplasmic bodies were bounded by single envelopes and contained finely granular, electron-dense viroplasms in which progeny virions formed aggregations or paracrystalline arrays. In mature viroplasmic bodies, viral aggregations and arrays were enveloped and segregated by multilayered membranous structures. Irregular, vesicular bodies occupied the electron-lucent areas between aggregations. Prior to cell lysis, membranous structures within viroplasmic bodies disintegrated in close association with secondary, membrane-bound bodies that were probably autophagic elements.
Thermal ablation: a potential solution for managing the small renal tumor.

Empirical evidence indicates that the number of small renal lesions being identified is rising. Typically treated with nephrectomy or partial nephrectomy, Stephen Solomon shares his view on the emerging role of radiofrequency ablation and cryotherapy in the management of small renal tumors.
Transanal Endoscopic Microsurgery is more Effective than Traditional Transanal Excision for Resection of Rectal Masses

Transanal endoscopic microsurgery, developed by Buess in the 1980s, has become increasingly popular in recent years. No large studies have compared the effectiveness of transanal endoscopic microsurgery with traditional transanal excision. Between 1990 and 2005, 171 patients underwent traditional transanal excision (n = 89) or transanal endoscopic microsurgery (n = 82) for rectal neoplasms. Medical records were reviewed to determine type of surgery, resection margins, specimen fragmentation, complications, recurrence, lesion type, stage, and size. The groups were similar with respect to age, sex, lesion type, stage, and size. Mean follow-up was 37 months. There was no difference in the complication rate between the groups (transanal endoscopic microsurgery 15 percent vs. traditional transanal excision 17 percent, P = 0.69). Transanal endoscopic microsurgery was more likely to yield clear margins (90 vs. 71 percent, P = 0.001) and a nonfragmented specimen (94 vs. 65 percent, P < 0.001) compared with transanal excision. Recurrence was less frequent after transanal endoscopic microsurgery than after traditional transanal excision (5 vs. 27 percent, P = 0.004). Transanal endoscopic microsurgery is the technique of choice for local excision of rectal neoplasms.
Diffusion Tensor Imaging of the Brain

Diffusion tensor imaging (DTI) is a promising method for characterizing microstructural changes or differences with neuropathology and treatment. The diffusion tensor may be used to characterize the magnitude, the degree of anisotropy, and the orientation of directional diffusion. This review addresses the biological mechanisms, acquisition, and analysis of DTI measurements. The relationships between DTI measures and white matter pathologic features (e.g., ischemia, myelination, axonal damage, inflammation, and edema) are summarized. Applications of DTI to tissue characterization in neurotherapeutic applications are reviewed. The interpretations of common DTI measures (mean diffusivity, MD; fractional anisotropy, FA; radial diffusivity, Dr; and axial diffusivity, Da) are discussed. In particular, FA is highly sensitive to microstructural changes, but not very specific to the type of changes (e.g., radial or axial). To maximize the specificity and better characterize the tissue microstructure, future studies should use multiple diffusion tensor measures (e.g., MD and FA, or Da and Dr).
Reduction of simulation cost and error for particle simulations of rarefied flows

Abstract The computational cost in simulating a steady, rarefied gas flow by use of a particle method is shown to be greatly reduced if the simulation employs an average number of particles per cell that is greater than a certain (approximate) minimum. The minimum value depends on the rms level of statistical fluctuations judged acceptable in the resultant data and is found to be significantly greater than values often used in practice when two- and three-dimensional flows are simulated. The computational cost is found to remain fixed for values greater than the minimum, showing that the ensemble- and time-averaging operations become interchangeable. For the problem studied, it is shown that a regime exists for which computational cost may be reduced by a factor of 10 by merely increasing the size of the simulation by a factor of five, when holding the rms level of statistical fluctuations fixed.
Histochemical profiles of guinea-pig intrafusal fibres in normal muscles and after denervation, cordotomy and tenotomy

Histochemical profiles of intrafusal fibres were analysed in normal muscles and in denervated, cordotomized and tenotomized preparations. Based on ATPase activity at polar regions, normal intrafusal fibres were classified as (I) ATPase-light fibres showing low or low-moderate activity when pre-incubated in either an acid or alkaline medium; (2) ATPase-dark fibres demonstrating high activity when preincubated in either an acid or alkaline medium and (3) ATPase-reversing fibres displaying low to moderate activity when pre-incubated in an acid medium, but showing high activity when pre-incubated in an alkaline medium. Four weeks after nerve section contrasting responses were seen between intrafusal fibre types. The ATPase-reversing fibres showed large decreases in polar cross-sectional area and NADH-diaphorase (NADH-D) activity, whereas fibres of the ATPase-light and ATPase-dark types were less subject to atrophy and their NADH-D levels were frequently increased. This differential effect suggests that ATPase-reversing fibres are trophically more dependent on neural innervation than ATPase-light and ATPase-dark fibres. After cordotomy and tenotomy no such marked differential responses were noted between fibre types.
Determination of the scattering matrix by use of the Sturmian representation of the wave function

We derive an expansion of the scattering matrix for any reasonable atomic potential V(r) by using the Sturmian expansion of the Coulomb Green's function. We demonstrate the method for the case where V(r) is a Coulomb potential plus a Yukawa potential.
Preparation, characterization, and activity of Al2O3-supported V2O5 catalysts

Abstract A series of activated alumina-supported vanadium oxide catalysts with various V 2 O 5 loadings ranging from 5 to 25 wt% have been prepared by wet impregnation technique. A combination of various physicochemical techniques such as BET surface area, oxygen chemisorption, X-ray diffraction (XRD), temperature-programmed reduction (TPR), thermal gravimetric analysis (TGA), and Fourier transform infrared (FTIR) were used to characterize the chemical environment of vanadium on the alumina surface. Oxygen uptakes were measured at 370 °C with prereduction at the same temperature, which appears to yield better numerical values of dispersion and oxygen atom site densities. XRD and FTIR results suggest that vanadium oxide exists in a highly dispersed state below 15 wt% V 2 O 5 loading and in the microcrystalline phase above this loading level. TPR profiles of V 2 O 5 /Al 2 O 3 catalysts exhibit only a single peak at low temperature up to 15 wt% V 2 O 5 . It is suggested that the low-temperature reduction peak is due to the reduction of surface vanadia, which has been ascribed to the tetrahedral coordination geometry of the V ions. TPR of V 2 O 5 /Al 2 O 3 at higher vanadia loadings exhibited three peaks at reduction temperatures, indicating that bulk-like vanadia species are present for these catalysts only at higher vanadia loadings, with V ions in an octahedral coordination. The TPR profiles of V 2 O 5 /Al 2 O 3 catalysts indicate that at loadings lower than 15% vanadia forms isolated surface vanadia species, while two-dimensional structure and V 2 O 5 crystallites become prevalent in highly loaded (>15% V 2 O 5 ) systems. Liquid-phase oxidation of ethylbenzene to acetophenone has been employed as a chemical probe reaction to examine the catalytic activity. Ethylbenzene oxidation results reveal that 15%V 2 O 5 /Al 2 O 3 is more active than higher vanadia loading catalysts.
Modified forms of histones H3 and H4 exhibit seasonal patterns in testes of the sea star Asterias vulgaris

Abstract 1. 1. A seasonal comparison of histones from testes of Asterias vulgaris , which exhibit an annual reproductive cycle and retain histones in mature sperm, indicated a relative increase in H3 and H4 variants during the period of enhanced spermatogonial mitosis. 2. 2. PAGE bands representing these proteins were characteristic of triply modified (acetylated) forms of H3 and singly modified H4. 3. 3. Doubly modified H3 and unmodified H4 were the dominant subfractions in chromatin from ripe testes containing mature spermatozoa.
DEVELOPMENT OF PERCEIVED ADOLESCENT RELATIONSHIP SCALE

The purpose of the present study was to develop an easily administered scale to assess adolescents' perceptions of both their own social competence and social participation in relationships. Six items were used to generate two factors that accounted for about 68% of the variance.
The Impact of Cultural and Ecological Change on Amazonian Fisheries

Abstract Fish have long provided an important item in the diet of Amazonians, but ecological and cultural changes threaten the long-term productivity of aquatic ecosystems. Population growth, the opening of extra-regional markets and the introduction of new or improved technologies, have increased pressure on fisheries of Amazonia, the world's largest freshwater catchment. Habitat destruction due to agricultural expansion and development projects also threatens to undermine fishing yields. Modern conservation practices, such as the establishment of parks and reserves and the enactment of protective legislation, are only gaining a tentative foothold in the region.
The Analysis of Social Networks

Many questions about the social organization of medicine and health services involve interdependencies among social actors that may be depicted by networks of relationships. Social network studies have been pursued for some time in social science disciplines, where numerous descriptive methods for analyzing them have been proposed. More recently, interest in the analysis of social network data has grown among statisticians, who have developed more elaborate models and methods for fitting them to network data. This article reviews fundamentals of, and recent innovations in, social network analysis using a physician influence network as an example. After introducing forms of network data, basic network statistics, and common descriptive measures, it describes two distinct types of statistical models for network data: individual-outcome models in which networks enter the construction of explanatory variables, and relational models in which the network itself is a multivariate dependent variable. Complexities in estimating both types of models arise due to the complex correlation structures among outcome measures.
The virus battles: IFN induction of the antiviral state and mechanisms of viral evasion

Response to IFN involves a rapid and direct signal transduction mechanism that quickly reports that presence of extracellular cytokine to the cell nucleus, preserving the specificity inherent in cytokine-receptor interactions to transcriptionally induce expression of a set of genes encoding important antiviral proteins. Establishment of the resulting antiviral state provides a crucial initial line of defense against viral infection. Studies of IFN-deficient cells and animals derived by gene targeting have demonstrated the essential nature of IFN-mediated innate immunity. The long co-evolutionary history of viruses with their hosts has seen the development of a variety of evasive adaptations that allow viruses to circumvent or inactivate host antiviral mechanisms. Further understanding of both host and viral components of this battle may provide important new strategies for vaccine development and creation of novel antiviral compounds.
Compressible liquid drop nuclear model and mass formula

Abstract We develop a refined version of the compressible liquid drop model of the nucleus introduced by Baym, Bethe, and Pethick; and by fitting the model to the binding and Coulomb energies of heavy nuclei, we redetermine phenomenologically the bulk and surface properties of symmetric nuclear matter. The principal refinement is in the description of the surface tension, the semi-phenomenological expression used here being constructed to agree with microscopic surface energy calculations. The resulting six parameter mass formula reproduces known nuclear masses with an rms deviation of 2.6 MeV (attributable primarily to shell effects). Because the compressible liquid drop model contains the physics needed to describe the gross properties of both ordinary and neutron star nuclei, we expect this mass formula to be a reliable indicator of the masses of highly neutron-rich nuclei.
Hardness and Fracture Toughness of Pressureless-Sintered Boron Carbide (B4C)

This is a companion work to our previous study on the pressureless sintering of boron carbide (B 4 C). The Vickers hardness and indentation fracture toughness of B 4 C compacts were measured after various sintering heat treatments. Increases in hardness and decreases in indentation fracture toughness as the grain size decreased in sintered B 4 C were attributed to the effects of more rapid strain hardening associated with dislocation pileups at grain boundaries.