cssi/SciSciGPT-SciSciNet huggingface dataset:
Czochralski-grown proustite and related compounds

Abstract The Czochralski technique as applied to synthesis of single-crystal proustite Ag 3 AsS 3 , pyrargyrite Ag 3 SbS 3 , and related compounds is described. Nucleation of the crystal was accomplished by a cold-finger technique using an iridium rod. The melt was covered with a disk to decrease evaporation losses and to segregate the chemically-formed dross from the liquid-solid interface. In addition, a non-stoichiometric variation of composition, involving excesses of the more volatile components, was used to lengthen the life of the melt. Crystals were pulled as fast as 75 mm/hour but best quality material, i.e. material without cellular structure, was obtained using growth rates of approximately 2 mm/hr. Ingots as large as 2.4 cm in diameter were grown without core effects at slow pulling rates. Initial experiments indicated a strong tendency for the heaxagonal crystal to grow in the c -direction, with a lesser preference for 60° orientation. Large single crystals of good quality were obtained and optical properties were investigated in the spectral range 0.5 to 25 μm on X -cut and Z -cut plates. Proustite crystals with resistivities of approximately 10 8 Ω-cm were obtained.
High-Resolution Inductively Coupled Plasma Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

Initial results obtained by incorporation of an inductively coupled plasma (ICP) ion source with a Fourier transform ion cyclotron resonance (FTICR) mass spectrometer are reported, along with spectra which demonstrate sub-milligram-per-liter detection limits and high mass resolution (mass resolving power, m/Δm10%V = 7000−10 000). Also shown is an ICP-FTICR spectrum with ultrahigh resolving power (m/Δm10%V = 88 000). Both instrumental configurations used to conduct this work, one at the University of Florida, and the other at the National High Magnetic Field Laboratory, are described. Also included are concise results from a computer aided interference study designed to enumerate mass spectral interferences requiring mass resolving power in excess of 10 000.
Gender Differences in Children's and Adolescents' Career Aspirations: A Follow-up Study

Career choices and their relation to personal and family background variables were studied in a sample of 148 children (68 females and 80 males) at two points in time: when the participants were between 8 and 13 years of age (Phase 1) and approximately S years later, when they were between 13 and 18 years of age (Phase 2). Male andfemale respondents during both phases chose largely nonoverlapping careers. Boys' choices were heavily gender-stereotyped during both developmental periods. In contrast over one quarter of the females during Phase 1 and close to one half during Phase 2 chose male-dominated occupations. Boys' ideal and realistic career choices did not differ in the degree to which they were gender-typed. Girls'realistic career nominations, however, included a significantly higher percentage of female incumbents in the labor force than did their ideal choices. Gender differences in career choices were not accompanied by differences in several family background and personal variables except for the...
The Effects of Adrenocorticotropic Hormone and Heat Stress on the Distribution of Lymphocyte Populations in Immature Male Chickens

This study investigated the effects of heat stress and adrenocorticotropic hormone (ACTH) on the distribution of lymphocyte populations. Two experiments were conducted; each used 12-wk-old Cornell K-strain male chickens. In Experiment 1, birds were exposed to a temperature of 35 C, 6 h/d for 5 d and control birds were maintained at 24 C. In Experiment 2, birds received daily i.m. injections of 50 IU/kg body weight of ACTH for 5 d and control birds received .9% saline. On Day 6, blood and spleens were collected and lymphocytes were isolated. Indirect immunofluorescent labeling of lymphocytes were performed to detect B lymphocytes, CD4+ cells, and CD8+ cells. Neither ACTH injection nor heat stress affected percentages of B lymphocytes in the blood or the spleen. The CD4+ cells decreased significantly in the blood of ACTH-injected and heat-stressed birds and significantly increased in the spleens of heat-stressed birds. The CD4+ cells in the spleens of ACTH-injected birds did not differ from controls. The CD8+ cells significantly declined in the blood following both ACTH injection and heat stress and significantly increased in the spleen of the ACTH-injected birds but did not differ from controls in the heat-stressed birds. These results indicate that stress factors lead to redistribution of different lymphocyte populations.
Heavy-ion-induced modification of structural and mechanical properties of carbon-nanotube aerogels

Abstract We study the effect of 2 MeV Xe ion bombardment at room temperature on the microstructure and mechanical properties of cross-linked carbon-nanotube-based nanoporous carbons. Irradiation causes a gradual densification and a decrease in the surface roughness of monoliths, an increase in Young’s modulus and failure stress, a decrease in the failure strain, and smoothening of nanoligament surfaces. Our results demonstrate a potential of heavy-ion bombardment for a controlled modification of nanoporous carbons.
A Familial Amyotrophic Lateral Sclerosis-associated A4V Cu,Zn-Superoxide Dismutase Mutant Has a Lower Km for Hydrogen Peroxide CORRELATION BETWEEN CLINICAL SEVERITY AND THE Km VALUE

Point mutations of Cu,Zn-superoxide dismutase (Cu,Zn-SOD) have been linked to familial amyotrophic lateral sclerosis (FALS). We reported that Cu,Zn-SOD can catalyze free radical generation and a FALS mutant, G93A, exhibits an enhanced free radical-generating activity, while its dismutation activity is identical to that of the wild-type enzyme (Yim, M. B., Kang, J.-H., Yim, H.-S., Kwak, H.-S., Chock, P. B., and Stadtman, E. R. (1996) Proc. Natl. Acad. Sci. U. S. A. 93, 5709-5714). The A4V mutation is both the most commonly detected of FALS-associated SOD1 mutations and among the most clinically severe (Rosen, D. R., Bowling, A. C., Patterson, D., Usdin, T. B., Sapp, P., Mezey, E., McKenna-Yasek, D., O'Regan, J. P., Rahmani, Z., Ferrante, R. J., Brownstein, M. J., Kowall, N. W., Beal, M. F., Horvitz, H. R., and Brown, R. H., Jr. (1994) Hum. Mol. Genet. 3, 981-987). We cloned the cDNA for the FALS A4V mutant, overexpressed the protein in Sf9 insect cells, purified the protein, and studied its enzymic activities. Our results show that the mutant and wild-type enzymes contain one copper ion per subunit and have identical dismutation activities. However, the free radical-generating activity of the mutant, as measured by the spin trapping method at low H2O2 concentration, is enhanced relative to that of the wild-type and G93A enzyme (wild-type G93A > A4V, while the kcat is identical for these enzymes. Thus, the FALS symptoms are not associated with the reduction in the dismutation activity of the mutant enzyme. The fact that the A4V mutant has the lowest Km for H2O2 is correlated to the clinical severity observed with the A4V patients, if FALS is associated with a differential gain of the free radical-generating function of the Cu,Zn-SOD mutant.
Rheological study of self‐crosslinking and co‐crosslinking of ammonium zirconium carbonate and starch in aqueous solutions

Different from common hydrogel systems formed by a polymer and a crosslinker, a hydrogel consisting of both self-crosslinkable ammonium zirconium carbonate (AZC) and co-crosslinkable starch was investigated in this study using rheological measurements. The evolution of viscoelastic properties of AZC solutions and AZC-starch mixtures was characterized, and the crosslinking kinetics was determined. It was found that for both AZC self-crosslinking and AZC-starch co-crosslinking, the initial bond formation rate and the gel strength exhibited a power law scaling with polymer concentrations. The competition reaction between self-crosslinking and co-crosslinking indicates that the gelation kinetics strongly depends on the AZC concentration but less depends on starch concentration. The temperature dependence of crosslinking was described by the Arrhenius plots which demonstrate a good linearity. It was determined that the activation energy of AZC self-crosslinking was approximately 145–151 kJ/mol, and the activation energy of AZC-starch co-crosslinking was 139 kJ/mol. The effect of solution pH on the crosslinking process was also studied. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
A space for inflections: following up on JMM’s special issue on mathematical theories of voice leading

Journal of Mathematics and Music's recent special issue 7(2) reveals substantial common ground between mathematical theories of harmony advanced by Tymoczko, Hook, Plotkin, and Douthett. This paper develops a theory of scalar inflection as a kind of voice-leading distance using quantization in voice-leading geometries, which combines the best features of different approaches represented in the special issue: it is grounded in the concrete sense of voice-leading distance promoted by Tymoczko, invokes scalar contexts in a similar way as filtered point-symmetry, and abstracts the circle of fifths like Hook's signature transformations. The paper expands upon Tymoczko's ‘generalized signature transform’ showing the deep significance of generalized circles of fifths to voice-leading properties of all collections. Analysis of Schubert's Notturno for Piano Trio and ‘Nacht und Traume’ demonstrate the musical significance of inflection as a kind of voice leading, and the value of a robust geometrical understanding ...
Impaired retinal vasodilator responses in prediabetes and type 2 diabetes.

Purpose: In diabetes, endothelial dysfunction and subsequent structural damage to blood vessels can lead to heart attacks, retinopathy and strokes. However, it is unclear whether prediabetic subjects exhibit microvascular dysfunction indicating early stages of arteriosclerosis and vascular risk. The purpose of this study was to examine whether retinal reactivity may be impaired early in the hyperglycaemic continuum and may be associated with markers of inflammation. Methods: Individuals with prediabetes (n = 22), type 2 diabetes (n = 25) and healthy age and body composition matched controls (n = 19) were studied. We used the Dynamic Vessel Analyzer to assess retinal vasoreactivity (percentage change in vessel diameter) during a flickering light stimulation. Fasting highly sensitive c-reactive protein (hs-CRP), a marker of inflammation, was measured in blood plasma. Results: Prediabetic and diabetic individuals had attenuated peak vasodilator and relative amplitude changes in retinal vein diameters to the flickering light stimulus compared with healthy controls (peak dilation: prediabetic subjects 3.3 ± 1.8%, diabetic subjects 3.3 ± 2.1% and controls 5.6 ± 2.6%, p = 0.001; relative amplitude: prediabetic subjects 4.3 ± 2.2%, diabetic subjects 5.0 ± 2.6% and control subjects 7.2 ± 3.2%, p = 0.003). Similar findings were observed in retinal arteries. Levels of hs-CRP were not associated with either retinal vessel response parameters. Conclusion: Retinal reactivity was impaired in prediabetic and type 2 diabetic individuals in parallel with reduced insulin sensitivity but not associated with levels of hs-CRP. Retinal vasoreactivity measurements may be a sensitive tool to assess early vascular risk.
Experimental Investigation of Leak-Rate Performance of a Subscale Composite Elastomer-Retainer Docking Seal

A novel docking seal was investigated for application to the main interface seal of NASA’s low-impact docking system. This interface seal was designed to maintain acceptable leak rates while being exposed to the harsh environmental conditions of outer space. In this experimental evaluation, the leak rate of a candidate docking-seal assembly was characterized and evaluated. The composite seal was manufactured from silicone elastomer S0383-70, vacuum molded into a metal retaining ring. Four seal designs were considered with unique characteristic heights. The leak-rate performance was characterized through a mass point leak-rate method by monitoring gas properties within an internal control volume. The leak rates of the seals were measured at representative docking temperatures of −58, +73, and +122°F for all four seal designs and characterized at 100, 74, and 48% of full closure. For all conditions, considered the candidate seal assemblies met the leak-rate criteria derived from the approximate mission requ...
Estimation of the soil heat flux/net radiation ratio from spectral data

Reliable spatial averages of surface energy balance components are difficult to obtain without an extensive hydrological measurement system. Our objective was to develop a method using remote sensing for estimating soil heat flux, one component of the surface energy balance, for a range of canopy conditions that will be applicable to regional surface energy balance studies. Net radiation (Rn) and soil heat flux (G) were measured during several days in fields of bare soil, alfalfa, and cotton at the Maricopa Agricultural Center, near Phoenix, AZ. Ground-based measurements of reflectance factors were also obtained with a multiband radiometer. Midday values of the ratio of soil heat flux and net radiation (G/Rn) were linearly related to the simple ratio and normalized difference vegetation indices. Relative to measurement errors, the estimates of G/Rn for cotton were found to be practically insensitive to changes in the value of the vegetative indices caused by spectral data collected at significantly different solar zenith and azimuth angles. Thus, multispectral data may provide a means of computing a more accurate area-averaged soil heat flux for regional energy balance studies.
Organ blood flow during arteriovenous carbon dioxide removal.

Animal models of arteriovenous carbon dioxide removal (AVCO2R) have achieved lung rest during treatment of severe respiratory failure, with total CO2 removal at arteriovenous shunt flow rates of 10% to 25% of cardiac output (CO). Previously, no statistically significant changes were reported in heart rate, cardiac output, mean arterial pressure, or pulmonary arterial pressure during prolonged (7 days) AVCO2R with shunt flows to 25% of CO. In this study, to determine the effect of various shunt levels on organ blood flow, colored microspheres were used in a conscious ovine model of AVCO2R. A low resistance 2.5 m2 oxygenator was placed in a simple carotid-to-jugular arteriovenous circuit. The AVCO2R flow (Qb) was incrementally increased to 5%, 10%, 15%, 20%, and 25% of baseline CO. After equilibration, colored microspheres were injected into a left atrial catheter while reference blood was withdrawn from an arterial line at a constant rate. Organ blood flow obtained by measuring microspheres in the tissues, showed approximately a 10–20% decrease at a 5% shunt, but remained relatively unchanged thereafter at up to a 25% shunt, and was well tolerated without hemodynamic sequelae or evidence of end organ ischemia. It was concluded that AVCO2R can achieve lung rest during respiratory failure at flow rates of 10–25% CO, with a resultant mild decrease in critical organ blood flow that appears well tolerated. ASAIO Journal 1997; 43:M821-M824.
Effect of social feedback on learning rate and cognitive distortions among women with bulimia

A group of college women diagnosed with bulimia nervosa and past depression ( n = 15) were compared to women with no bulimia and past depression ( n = 46) and women with no bulimia and no past depression ( n = 88) on their rate of learning and cognitive distortions on a computerized mental maze task. Half of the participants in each group were randomly assigned to receive positive social feedback for correct responses during the learning task and half to receive negative social feed-back for errors. Participants with bulimia (and past depression) receiving negative feedback learned the task at a significantly faster rate ( p
The influence of parent population distribution on d2 values

The two measures of dispersion which are used in statistical quality control are ρ, the expected value of the range of samples of a uniform size n, and σ, the standard deviation of the population from which the samples are taken. Conversion of one into the other is facilitated by use of the quantity called d2 which is taken to be the ratio of ρ to σ. Tables of d2 versus n are reproduced in all texts on statistical quality control. These tables are predicated upon the parent population being normally distributed, an assumption which may be unjustified in many instances. To understand the consequences of this assumption of normality, a short table of d2 values based upon five distributions is presented. The five distributions are: normal, uniform, triangular, Erlang υ=1 (negative exponential), and Erlang υ=2. The sample size varies from two through 12, plus 15, 20, and 50. It was observed that for many values of n the normal distribution produced the largest value of d2, while the negative exponential distribution produced the smallest value. Depending upon the intended use, and whether Type I or Type II error is of more concern, one may wish to use d2 values based upon other than the normal distribution. Some recommendations are made. A derivation of the formula for computing ρ as a function of n which is dependent upon the parent population distribution is given in an appendix.
Utility of cleavable isotope coded affinity tagged reagents for quantification of low-copy proteins induced by methylprednisolone using liquid chromatography/tandem mass spectrometry

Gene expression changes underlie important biological and pharmacological responses. Although mRNA expression profiling is routine, quantification of low-abundance proteins, which typically represent key effectors of responses, remains challenging. A novel strategy was developed for sensitive and accurate quantification of low-abundance proteins in highly complex biological matrixes. First, the cysteine specificity of cleavable isotope-coded affinity tags (cICAT) was employed to reduce the complexity of the digested proteome of tissue homogenates and to improve the quantification of low-abundance proteins. Second, cICAT-treated tissue samples were analyzed on a capillary LC coupled to an ion trap MS to screen for the subset of cICAT-peptides, derived from target proteins of interest, that was successfully labeled and retrieved. Third, putatively identified peptides derived from target proteins were synthesized, cICAT-labeled, and used both to optimize multiple reactions monitoring (MRM) analysis and to co...
Spectral Sensitivity Determinations by Cutoff Filters

A series of 26 selenium glass filters with cutoffs uniformly paced over the visible spectrum is used as the basic set of filters to determine the relative spectral sensitivity function of a given photoelectric receiver. Certain characteristics of these filters, such as non-uniformity of transmittance across the filter surface and temperature dependence, impair the precision of the transmittance measurements as well as photocell-response measurements. Nevertheless it is possible to derive fairly well-conditioned matrices of difference functions obtained from the basic set of cutoff filters, which will allow a satisfactory determination of a spectral sensitivity function. Experimental as well as numerical implications are discussed in detail on the basis of a practical example.
One Person's View of EuCAP'201 0 from the West Side of the Pond

EUCAP 2010 was the first EuCAP that I have attended (Figure 11). Before I get distracted with details, I want to say up front that I was impressed with the conference. It was a huge success, and it will be an ambitious task to duplicate, much less to surpass. My pleasant experience started at the 2009 AP-S Awards Banquet, when Prof. Luis Jofre, General co-Chair of EuCAP'2010, attended the 2009 AP-S Symposium and received the 2009 H. A. Wheeler Prize Paper Award. At the banquet, Luis extended to me an invitation to present an invited paper at EuCAP'2010. This was followed later with an official invitation from both Luis and Juan Mosig, the general EuCAP series Chair. From my limited exposure while attending EuCAP'2010, here are some of my observations.
Inhibition of sickling in vitro by three purine-based antiviral agents: an approach to the treatment of sickle cell disease.

Abstract As a result of an in vitro screening effort the antiviral agent acyclovir was found to inhibit aggregation of hemoglobin S and the sickling of erythrocytes from individuals with sickle cell disease. Sickling of the erythrocytes was significantly inhibited at 200 μg/ml under essentially anaerobic conditions, considerably more hypoxic than the conditions in which sickling occurs in sickle cell patients. The structurally related guanine-based antiviral agents ganciclovir, valacyclovir, and penciclovir were also tested. Valacyclovir and ganciclovir showed comparable anti-sickling activity at concentrations similar to that of acyclovir. An examination of the shared structural characteristics of the four guanine derivatives linked anti-sickling activity to the presence of an oxygen atom alpha to the N 9 of the guanine moiety. These findings suggest a new approach in the search for new agents for the treatment of patients with sickle cell disease.
Early social isolation of the domestic cat: Responses during mechanical toy testing

Abstract Four male and four female kittens were reared in each of the following rearing conditions: (1) mother and a littermate; (2) alone with their mother; (3) brooder and littermate; (4) alone with a brooder. Each of the 32 kittens were separated briefly from their rearing condition once a week from 2–5 weeks of age. They were placed alone in an open field with a mechanical toy and a brooder replicate. The brooder-reared kittens spent more time with the toy than the mother-reared kittens. In fact, they spent more time with the mechanical toy than they did with the brooder. The brooder-reared kittens entered more squares than the mother-reared infants, but vocalized less than the mother-reared kittens. It was concluded that while all kittens appear to form social attachments, brooder-reared kittens do not seem to form substitute social attachments to a brooder.
Indentation versus uniaxial power-law creep: a numerical assessment

This study concerns the employment of instrumented indentation to characterize the power-law creep response of metallic materials. Systematic numerical finite element analyses of conical indentation, under controlled constant indentation strain rates, were conducted. The model system is pure tin (Sn) and Sn-based alloy with known uniaxial power-law creep parameters, with their stress exponents ranging from 7 to 10. It was found that the constant indentation strain rate results in a steady-state hardness which is independent of indentation depth. The indentation-derived stress exponents are almost identical to those of uniaxial creep, leading to parallel lines of strain rate versus creep stress on the logarithmic scale. A remarkably consistent ratio of uniaxial strain rate and indentation strain rate, 0.33, was obtained for all the model materials considered.
Recipes for reading : community cookbooks, stories, histories

The community cookbook is a familiar item in many kitchens. Usually compiled by women and sold to raise funds for a charitable cause, these collections of recipes may seem to be utilitarian objects that exhibit little if any narrative interest. But this is hardly the case. In Recipes for Reading, scholars from a variety of disciplines examine community cookbooks as complex texts deserving serious study. The contributors contend that such cookbooks have stories to tell about the lives and values of the women who wrote them, stories that are autobiographical in most cases, historical in some, and fictive in others.
Prosocial coping and substance use during pregnancy

In structured interviews of pregnant inner-city residents, 38 substance users reported more current liking of drugs and polysubstance use, disengagement coping, depressive symptoms, negative affect, and antisocial behavior than did 45 nonusers. During videotaped interviews, trained observers coded less warmth and less prosocial information exchange (e.g., self-disclosure, question asking) among users. Factor analysis of measures of coping and its concomitants yielded a three-factor (prosocial, antisocial, asocial) solution, with asocial and antisocial coping predominating among substance users. These results suggest that coping has emotional, social, and cognitive elements. This study is the first to demonstrate an association between a substance-using lifestyle and limited prosocial information exchange.
Multisensor Image Registration: Experimental Verification

A general multisensor image processor and image model are described and experimental verification of their use are provided. The pixel correlation coefficient is shown to be an adequate measure of the statistical independence of the gray levels in a multisensor image pair and to be of use as a guide to selecting various preprocessing operators. Experimental results obtained on the various multisensor image data bases verify our theory Quite well and have contributed considerable practical insight into the processing of imagery with random contrast reversal intensity differences.
Constructing minimal spanning/Steiner trees with bounded path length

This paper presents an exact algorithm and two heuristics for solving the Bounded path length Minimal Spanning Tree (BMST) problem. The exact algorithm which is based on iterative negative-sum-exchange(s) has polynomial space complexity and is hence more practical than the method presented by Gabow. The first heuristic method (BKRUS) is based on the classical Kruskal MST construction. For any given value of parameter /spl epsiv/, the algorithm constructs a routing tree with the longest interconnection path length at most (1+/spl epsiv/).R, and empirically with cost at most 1.19 times cost (BMST*) where R is the length of the direct path from the source to the farthest sink and BMST* is the optimal bounded path length MST. The second heuristic combines BKRUS and negative-sum-exchange(s) of depth 2 to improve results. Extensions of these techniques to the bounded path length Minimal Steiner Trees, using the Elmore delay model are presented as well. Empirical results demonstrate the effectiveness of these algorithms on a large benchmark set.
TOLERANCE TO BACTERIAL PYROGENS II. RÔLE OF THE RETICULO-ENDOTHELIAL SYSTEM

In experiments designed to elucidate the mechanism by which tolerance to bacterial pyrogens is developed, the following observations were made: 1. Animals whose febrile reactions to bacterial pyrogens were markedly diminished, as a result of repeated injections, showed increases in response following R-E blockade. 2. Pyrogenic substances disappeared from the circulating blood more rapidly in rabbits rendered pyrogen-tolerant than in normal animals. Lack of specificity was shown by the fact that rabbits previously injected with Eberthella typhosa bacterial vaccine were able to remove the pyrogens of Serratia marcescens and Pseudomonas aeruginosa from their blood more rapidly than normal animals. 3. R-E blockade-retarded the speed of disappearance of pyrogens from the circulating blood of animals which had been rendered relatively tolerant by previous injections of these substances. A possible mechanism for the development of unresponsiveness to bacterial pyrogens is suggested.
Inclusive ϱ° production in π−p interactions at 205 GeV/c

Abstract The inclusive ϱ ° production cross section has been measured in the reaction π − p → π + π − X at 205 GeV/ c . We find σ ( ϱ ° ) = 13.5 ± 3.4 mb, with most of the production occuring in the central region. Assuming σ ( ϱ + ) ≈ σ ( ϱ − ) ≈ σ ( ϱ ° ), it is concluded that approximately one-third of the pions at this energy come from ϱ -decay.
Thermal energy reactions of H+3 and H3O+ with a series of small organic molecules

Abstract A flowing afterglow has been used to determine the rate coefficients and ion product distributions for the reactions of H + 3 and H 3 O + with the small organic molecules CH 3 OH,CH 3 CHO, C 2 H 5 OH, (CH 3 ) 2 O, (CH 3 ) 2 CO and (C 2 H 5 ) 2 O at 300 K. The rate coefficients for all the reactions are close to the average dipole orientation collisional values, indicating that the reactions have unit efficiency. However, the products for the H + 3 and H 3 O + reactions are very different. The H 3 O + reactions proceed almost totally by non-dissociative proton transfer, as dictated by reaction energetics. The H + 3 reactions are much more exothermic and non-dissociative proton transfer is not the only process, the reactions being dominated by many dissociative processes leading to the production of ions such as CH + 3 , HCO + , H 3 CO + , C 2 H + 5 and C 2 H 5 O + . The data are compared with previous measurements where possible, and the mechanisms of the reactions are discussed.
Covalent labeling of nuclear vitamin D receptor with affinity labeling reagents containing a cross-linking probe at three different positions of the parent ligand: structural and biochemical implications.

Abstract Structure–functional characterization of vitamin D receptor (VDR) requires identification of structurally distinct areas of VDR-ligand-binding domain (VDR-LBD) important for biological properties of 1α,25-dihydroxyvitamin D 3 (1,25(OH) 2 D 3 ). We hypothesized that covalent attachment of the ligand into VDR-LBD might alter ‘surface structure’ of that area influencing biological activity of the ligand. We compared anti-proliferative activity of three affinity alkylating derivatives of 1,25(OH) 2 D 3 containing an alkylating probe at 1,3 and 11 positions. These compounds possessed high-affinity binding for VDR; and affinity labeled VDR-LBD. But, only the analog with probe at 3-position significantly altered growth in keratinocytes, compared with 1,25(OH) 2 D 3 . Molecular models of these analogs, docked inside VDR-LBD tentatively identified Ser237 (helix-3: 1,25(OH) 2 D 3 -1-BE), Cys288 (β-hairpin region: 1,25(OH) 2 D 3 -3-BE,) and Tyr295 (helix-6: 1,25(OH) 2 D 3 -11-BE,) as amino acids that are potentially modified by these reagents. Therefore, we conclude that the β-hairpin region (modified by 1,25(OH) 2 D 3 -3-BE) is most important for growth inhibition by 1,25(OH) 2 D 3 , while helices 3 and 6 are less important for such activity.
Laparoscopic Roux-en-Y gastric bypass: transoral or transgastric anvil placement?

Background: Laparoscopic techniques have been used to perform the Roux-en-Y gastric bypass (RYGBP). The gastrojejunostomy may be constructed using an end-to-end anastomosis (EEA) stapler. Most reports describe passing the EEA anvil transorally using an esophagogastroscope and a pullwire technique. Method: We describe problems experienced using this technique and present an alternative method. Results: Esophageal injury may occur during laparoscopic RYGBP (LRYGBP) using the transoral anvil placement technique. When the anvil is retrieved into the gastric pouch, the anvil may become lodged at the cricopharngeus muscle. Dislodgment can be problematic and time-consuming. We present a case of mild esophageal injury which occurred during transoral anvil placement. The patient had transient postoperative dysphagia and recovered without sequelae. We present an alternative method in which the anvil is passed through a gastrotomy. Conclusion: Transgastric anvil placement alleviates the need for endoscopy, thereby saving time and resources.This technique eliminates the potential for esophageal injury. The transgastric anvil placement technique has proven reliable. The transgastric method may make the LRYGBP operation safer and easier to perform.
Mobile Navigation Using Haptic, Audio, and Visual Direction Cues with a Handheld Test Platform

This paper reports on a series of user experiments evaluating the design of a multimodal test platform capable of rendering visual, audio, vibrotactile, and directional skin-stretch stimuli. The test platform is a handheld, wirelessly controlled device that will facilitate experiments with mobile users in realistic environments. Stimuli rendered by the device are fully characterized, and have little variance in stimulus onset timing. A series of user experiments utilizing navigational cues validates the function of the device and investigates the user response to all stimulus modes. Results show users are capable of interpreting all stimuli with high accuracy and can use the direction cues for mobile navigation. Tests included both stationary (seated) and mobile (walking a simple obstacle course) tasks. Accuracy and response time patterns are similar in both seated and mobile conditions. This device provides a means of designing and evaluating multimodal communication methods for handheld devices and will facilitate experiments investigating the effects of stimulus mode on device usability and situation awareness.
Frequency and significance of conduction defects early after orthotopic heart transplantation

To define the clinical significance of conduction defects after orthotopic heart transplantation sequential electrocardiograms (ECG) of 124 patients were analyzed during their postoperative hospital stay. The first ECG was abnormal in 90 patients (73%), with a predominance of right bundle branch block, and normal in 34 (27%). Sex, age, mean donor ischemic time, duration of aortic cross clamping and use of previous antiarrhythmic therapy were not significantly different in the 2 groups. During hospital follow-up, patients were grouped according to evolution of the initial electrocardiographic abnormalities. In group 1, 25 patients continued to have an initially normal ECG. In groups 2 and 3, 30 and 48 patients, respectively, had evidence of transient and permanent conduction defects. The 21 patients in group 4 showed progressive deterioration of conduction with either a new (9 patients) or worsening preexisting conduction defect (12 patients). The evolution of the initial ECG was strongly dependent on the duration of the donor heart ischemic time and the severity of the in-hospital cardiac rejection. Patients with persistent conduction abnormalities had a statistically longer ischemic time than either patients with normal or transient conduction defects (182 +/- 84 vs 144 +/- 68 and 130 +/- 66 minutes, p = 0.04). Although the overall percentage of patients with histologic evidence of moderate to severe rejection was similar across the groups, 66.6 and 46.1% of patients in groups 3 and 4, respectively, had multiple episodes of rejection compared with 16.6 and 0% in the remaining 2 groups (p = 0.044).(ABSTRACT TRUNCATED AT 250 WORDS)
Comparison of 3 bone substitutes in canine extraction sites.

Purpose: The purpose of this study was to evaluate the healing response with 3 different bone substitute materials in extraction sites in the dog. Materials and methods: Four dogs had their mandibular and maxillary premolars extracted atraumatically. The sites were immediately grafted with anorganic bovine bone (Bio-Oss, Osteohealth, Shirley, NY), Bone Source (Leibinger, Inc, Kalamazoo, MI), or Embarc (Lorenz Surgical, Jacksonville, FL), or left untreated as a control. After 8 weeks, the sites were removed for histologic evaluation of bone fill and the healing response. Results: All sites healed well without signs of infection. No significant differences were noted in the shape of the ridges between groups. The control sites had radiographic bone fill by 8 weeks. The Bio-Oss sites showed bone fill with a similar appearance to the control sites. The Bone Source and Embarc sites showed implant material taking up most of the extraction site. In all sites the control and Bio-Oss sites had significantly more bone formation than the Embarc and Bone Source sites (P <.05). The control sites contained woven bone. The Bio-Oss sites were similar to the control sites, but with remnants of Bio-Oss in the bone. The Bone Source and Embarc sites were filled predominantly with the graft material without evidence of resorption and replacement of the materials, and with minimal bone formation. Conclusions: Based on this study, the control and Bio-Oss sites were similar, with bone filling most of the extraction site. The other 2 materials did not show replacement with bone. © 2002 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 60:53-58, 2002
Signal recognition particle binds to ribosome-bound signal sequences with fluorescence-detected subnanomolar affinity that does not diminish as the nascent chain lengthens

The binding of signal recognition particle (SRP) to ribosome-bound signal sequences has been characterized directly and quantitatively using fluorescence spectroscopy. A fluorescent probe was incorporated cotranslationally into the signal sequence of a ribosome.nascent chain complex (RNC), and upon titration with SRP, a large and saturable increase in fluorescence intensity was observed. Spectral analyses of SRP and RNC association as a function of concentration allowed us to measure, at equilibrium, K(d) values of 0.05-0.38 nm for SRP.RNC complexes with different signal sequences. Competitive binding experiments with nonfluorescent RNC species revealed that the nascent chain probe did not alter SRP affinity and that SRP has significant affinity for both nontranslating ribosomes (K(d) = 71 nm) and RNCs that lack an exposed signal sequence (K(d) = 8 nm). SRP can therefore distinguish between translating and nontranslating ribosomes. The very high signal sequence-dependent SRP.RNC affinity did not decrease as the nascent chain lengthened. Thus, the inhibition of SRP-dependent targeting of RNCs to the endoplasmic reticulum membrane observed with long nascent chains does not result from reduced SRP binding to the signal sequence, as widely thought, but rather from a subsequent step, presumably nascent chain interference of SRP.RNC association with the SRP receptor and/or translocon.
The Nature of Bis(cyclopentadienyl)uranium Dichloride and Cyclopentadienyluranium Trichloride in Solution and in the Solid State

The composition of the compound (C/sub 5/H/sub 5/)/sub 2/UCl/sub 2/, prepared from uranium tetrachloride and thallium cyclopentadienide in DME (1,2-dimethyoxyethane), has been investigated in the solid state by infrared spectroscopy and x-ray powder diffraction, and in solution by electronic and /sup 1/H NMR spectroscopy. All results indicate that (C/sub 5/H/sub 5/)/sub 2/UCl/sub 2/ is a mixture of the known compounds (C/sub 5/H/sub 5/)/sub 3/UCl and (C/sub 5/H/sub 5/)UCl/sub 3/(DME). The structure of this latter species is proposed to be mer pseudooctahedral on the basis of solution NMR studies (which also show it to be sterochemically dynamic) and by analogy to the related complex, (CH/sub 3/C/sub 5/H/sub 4/)UCL/sub 3/(THF)/sub 2/, the solid-state molecular structure of which has been determined using single-crystal x-ray diffraction techniques. This compound crystallizes in the monoclinic space group P2/sub 1//n with four molecules in a cell of dimensions a = 10.481 (2) A, b = 12.981 (2) A, c = 13.834 (2) A, and ..beta.. = 105.86 (1)/sup 0/. Least-squares refinement of the 181 variables led to a value for the conventional R index (on F) of 0.058 for 3698 independent reflections having 2 theta/sub MoK..cap alpha..-bar/ 3 sigma(I). The coordinationmore » geometry about the uranium ion is approximately mer octahedral with the eta/sup 5/-CH/sub 3/C/sub 5/H/sub 4/ and one coordinated THF occupying trans axial positions, and the other THF and three chlorine atoms occupying equatorial positions. The U--C (cyclopentadienyl), U--Cl, and U--O distances average 2.720 (14), 2.623 (3), and 2.450 (8) A, respectively. The principal distortion of the coordination geometry from octahedral is a 0.47-A displacement of the uranium atom out of the equatorial plane toward the cyclopentadienyl ring. It is found that the THF ligands of (C/sub 5/H/sub 5/)UCl/sub 3/(THF)/sub 2/ are readily displaced by nitrogenous bases such as 2,2'-bipyridyl and 1,10-phenanthroline. 6 figures, 6 tables.« less
Syntheses and biological activity of amamistatin B and analogs.

Amamistatins A and B, natural products isolated from a strain of Nocardia, showed growth inhibition against three human tumor cell lines (IC50 0.24−0.56 μM). Structurally related mycobactins affect the growth of both mycobacterial and human cells through interference with iron chelation. To further probe the biological activity of this class of compounds, the total syntheses of amamistatin B and two analogs were completed, and the synthetic samples were screened for tumor cell growth inhibition, HDAC inhibition, and Mycobacterium tuberculosis growth inhibition. Amamistatin B (15) and diastereomer 18 were both active against MCF-7 cells (IC50 0.12−0.20 μM), and less so against PC-3 cells (IC50 8−13 μM). Amamistatin B only moderately inhibited the growth of M. tuberculosis (MIC 47 μM) but showed growth promotion of Mycobacterium smegmatis and other bacteria.
Physical CAD changes to incorporate design for lithography and manufacturability

The next few process generations (65 nm and below) will have serious lithography and manufacturing constraints since the feature size is shrinking much more rapidly than the wavelengths used in manufacturing the chips. This paper starts with a quick tutorial on the Design for Manufacturability problems of these process generations, concentrating primarily on the limitations of optical lithography. The remainder of the talk covers the changes to physical design tools, such as placement and routing, that are needed to cope with these problems.
Model Reference Adaptive Control of Large Structural Systems

Attention is given to model reference adaptive control procedures that do not require explicit parameter identification for large structural systems. Even though such applications have been shown to be feasible for multivariable systems, provided there exists a feedback gain matrix that makes the resulting input/output transfer function strictly positive real, it is shown here that this constraint is overly restrictive and that only positive realness is required. Subsequent consideration of a simply supported beam reveals that if actuators and sensors are collocated, then the positive realness constraint will be satisfied and the model reference adaptive control will then indeed be suitable for velocity following when only velocity sensors are available and for both position and velocity following when velocity plus scaled position outputs are measured. For both cases, all states are guaranteed to be stable, regardless of system dimension.
Electrophysiological evidence of emotion perception without central attention

The present study examined whether emotion perception requires central attentional resources. Specifically, we used a dual-task paradigm to examine whether people can direct their attention to a face expressing a target emotion even while they are still busy selecting a response to another task. Task 1 required an auditory discrimination (pure tone vs. noise). For Task 2, one happy face and one angry face were presented adjacent to each other. Participants were asked to find the face with a prespecified emotion and indicate its gender (Experiment 1) or location (Experiment 2). The stimulus–onset asynchrony (SOA) between the two tasks was varied. To determine where people were attending, we used an electrophysiological measure of attention known as the N2pc component of the event-related brain potential. The face expressing the target emotion elicited an N2pc effect, indicating attention capture, even when participants were already preoccupied with processing Task 1 (i.e., short SOAs). Thus, it appears tha...
RED gateway congestion control using median queue size estimates

This paper focuses on the queue size estimation problem in random early detection (RED) gateways. Queue size estimation plays a fundamental role in the congestion control dynamics of RED, as it determines gateways' awareness of network congestion, which in turn determines the packet dropping/marking decision. Conventional RED gateways use exponentially weighted moving averages (EWMA) to estimate the queue size. These infinite impulse response (IIR) filters require very small EWMA weights in order to effectively avoid nonlinear instabilities in RED and to filter out bursty increases in the queue size. While small EWMA weights enable gateways to accommodate transient congestion, they also lead to gateways' failure to closely track rapid queue size depletion and thus causes link under utilization. We investigate the use of simple nonlinear queue size estimators. In particular, we study the congestion control dynamics of a network where adaptive weighted median filters are used for queue size estimation by the gateways. Analytical results for the expected queue size in the steady state are derived. Under this new queue size estimation framework, design guidelines for the remaining RED parameters are provided. Simulation results show that the proposed algorithm provides greater network power, better prevention of global synchronization, and a fairer treatment to bursty traffic than the RED algorithm does.
Sympathoinhibition from ventrolateral periaqueductal gray mediated by the caudal midline medulla

Activation of neurons in the ventrolateral region of the periaqueductal gray (vlPAG) can elicit a decrease in renal sympathetic nerve activity and blood pressure. The present study investigated whe...
Mutation of SIMPLE in Charcot-Marie-Tooth 1C alters production of exosomes

Charcot–Marie–Tooth (CMT) disease is an inherited neurological disorder. Mutations in the small integral membrane protein of the lysosome/late endosome (SIMPLE) account for the rare autosomal-dominant demyelination in CMT1C patients. Understanding the molecular basis of CMT1C pathogenesis is impeded, in part, by perplexity about the role of SIMPLE, which is expressed in multiple cell types. Here we show that SIMPLE resides within the intraluminal vesicles of multivesicular bodies (MVBs) and inside exosomes, which are nanovesicles secreted extracellularly. Targeting of SIMPLE to exosomes is modulated by positive and negative regulatory motifs. We also find that expression of SIMPLE increases the number of exosomes and secretion of exosome proteins. We engineer a point mutation on the SIMPLE allele and generate a physiological mouse model that expresses CMT1C-mutated SIMPLE at the endogenous level. We find that CMT1C mouse primary embryonic fibroblasts show decreased number of exosomes and reduced secretion of exosome proteins, in part due to improper formation of MVBs. CMT1C patient B cells and CMT1C mouse primary Schwann cells show similar defects. Together the data indicate that SIMPLE regulates the production of exosomes by modulating the formation of MVBs. Dysregulated endosomal trafficking and changes in the landscape of exosome-mediated intercellular communications may place an overwhelming burden on the nervous system and account for CMT1C molecular pathogenesis.