cssi/SciSciGPT-SciSciNet huggingface dataset:
Dynamic sequestration of the recycling compartment by classical protein kinase C.

It has been previously shown that upon sustained stimulation (30-60 min) with phorbol esters, protein kinase C (PKC)α andβII become sequestered in a juxtanuclear region, the pericentrion. The activation of PKC also results in sequestration of transferrin, suggesting a role for PKC in regulating endocytosis and sequestration of recycling components. In this work we characterize the pericentrion as a PKC-dependent subset of the recycling compartment. We demonstrate that upon sustained stimulation of PKC, both protein (CD59, caveolin) and possibly also lipid (Bodipy-GM1) cargo become sequestered in a PKC-dependent manner. This sequestration displayed a strict temperature requirement and was inhibited below 32 °C. Treatment of cells with phorbol myristate acetate for 60 min led to the formation of a distinct membrane structure. PKC sequestration and pericentrion formation were blocked by hypertonic sucrose as well as by potassium depletion (inhibitors of clathrin-dependent endocytosis) but not by nystatin or filipin, which inhibit clathrin-independent pathways. Interestingly, it was also observed that some molecules that internalize through clathrin-independent pathways (CD59, Bodipy-GM1, caveolin) also sequestered to the pericentrion upon sustained PKC activation, suggesting that PKC acted distal to the site of internalization of endocytic cargo. Together these results suggest that PKC regulates sequestration of recycling molecules into this compartment, the pericentrion.
Pt-catalyzed combustion of CH4C3H8 mixtures

Abstract Experiments on a Pt foil, combined with simulations using a stagnation point flow model, were used to study the influence of propane on the combustion of methane in air over Pt catalysts. The steady-state multiplicity of the system was studied in terms of the surface temperature of the catalyst as a function of the input power. The system exhibited up to three stable steady states for some fuel ratios. Propane ignites at a much lower temperature and power input, and we observed that the whole mixture ignited at these conditions for sufficiently high propane contents. The model, which uses one-step global reaction rates for the kinetics, reproduced these results, predicting the ignition, extinction and autothermal temperatures fairly accurately. The nature of each stable state could be determined from the model. The low temperature stte is the extinguished state (with negligible reaction of either fuel), the intermediate state corresponds to only propane oxidation, and the third shows oxidation of both methane and propane. The model also predicts that the system exhibits two distinct autotherms for lean methane—propane mixtures.
A history of Islam among the African American Muslims of Richmond

L'emergence de l'Islam parmi les afro-americains de la ville de Richmond en Virginie n'est pas tres differente de celle des autres villes des Etats-Unis. On peut faire remonter cette histoire a 1955. Il n'y a pas de trace de mosquee ou de congregation musulmane a Richmond avant l'etablissement de la Nation de l'Islam dans les annees 1950. Environ deux cents familles musulmanes habitent Richmond et sa banlieue. Ceux qui ont un bon niveau d'instruction; ils travaillent dans des branches d'activite variees. L'education religieuse islamique est assez peu developpee
SIRT1 Mediates Central Circadian Control in the SCN by a Mechanism that Decays with Aging

SIRT1 is a NAD(+)-dependent protein deacetylase that governs many physiological pathways, including circadian rhythm in peripheral tissues. Here, we show that SIRT1 in the brain governs central circadian control by activating the transcription of the two major circadian regulators, BMAL1 and CLOCK. This activation comprises an amplifying circadian loop involving SIRT1, PGC-1α, and Nampt. In aged wild-type mice, SIRT1 levels in the suprachiasmatic nucleus are decreased, as are those of BMAL1 and PER2, giving rise to a longer intrinsic period, a more disrupted activity pattern, and an inability to adapt to changes in the light entrainment schedule. Young mice lacking brain SIRT1 phenocopy these aging-dependent circadian changes, whereas mice that overexpress SIRT1 in the brain are protected from the effects of aging. Our findings indicate that SIRT1 activates the central pacemaker to maintain robust circadian control in young animals, and a decay in this activity may play an important role in aging.
Enhanced Laser Shock by an Active Liquid Confinement

This letter investigates a unique process to generate the enhanced laser shock with a higher pressure by applying an active liquid confinement — hydrogen peroxide (H2O2). The mechanism of fast chemical etching-assisted laser ablation is proposed. As a result, comparing with utilizing water as confinement, the efficiency of underwater laser shock peening of aluminum alloy 6061 is improved by 150%, and the ablation rate of pulse laser ablation of zinc is enhanced by 300%. This method breaks the major limitation of underwater pulsed laser processing caused by the breakdown plasma.Copyright © 2012 by ASME
Why Drosophila to Study Phototransduction

This review recounts the early history of Drosophila phototransduction genetics, covering the period between approximately 1966 to 1979. Early in this period, the author felt that there was an urgent need for a new approach in phototransduction research. Through inputs from a number of colleagues, he was led to consider isolating Drosophila mutants that are defective in the electroretinogram. Thanks to the efforts of dedicated associates and technical staff, by the end of this period, he was able to accumulate a large number of such mutants. Particularly important in this effort was the use of the mutant assay protocol based on the "prolonged depolarizing afterpotential." This collection of mutants formed the basis of the subsequent intensive investigations of the Drosophila phototransduction cascade by many investigators.
Economics of food intake in mice: Energy yield of the reinforcer

One of the Zeitgeists of the field for the study of ingestive behavior is that organisms are endowed with internal self-regulatory mechanisms that ensure optimal nutrition. However, the alarming increase in the prevalence of obesity challenges us to reconsider the extent to which internal regulatory mechanisms affect food intake, especially in a free market economy. Cued by the pioneering work of George Collier and his students, we have been examining food intake (demand) in mice when the effort or price of food is manipulated. We present two new experiments in mice that investigate the effect of energy yield per unit of food earned on working for food. The first experiment shows that when the nominal energy yield of each food pellet is halved by cellulose dilution, mice show relatively inelastic calorie-related demand despite the fact the cellulose diluted diet is unpalatable. The second experiment shows that the size of the pellet reinforcer does not have a major effect on food demand except in the extreme condition of small reward and high unit price. New analyses of distributions of responding are presented which suggest that mice work for "target" numbers of food rewards with only a small influence of price or energy gain.
Determination of the pharmacodynamic interaction of propofol and dexmedetomidine during esophagogastroduodenoscopy in children.

Objectives Propofol is a sedative-hypnotic drug commonly used to anesthetize children undergoing esophagogastroduodenoscopy (EGD). Dexmedetomidine is a highly selective alpha-2 adrenergic receptor agonist that has been utilized in combination with propofol to provide anesthesia. There is currently no information regarding the effect of intravenous dexmedetomidine on the propofol plasma concentration-response relationship during EGD in children. This study aimed to investigate the pharmacodynamic interaction of propofol and dexmedetomidine when used in combination for children undergoing EGD. Methods A total of 24 children undergoing EGD, ages 3-10 years, were enrolled in this study. Twelve children received dexmedetomidine 1 microg x kg(-1) given over 10 min as well as a continuous infusion of propofol delivered by a computer-assisted target-controlled infusion (TCI) system with target plasma concentrations ranging from 2.8 to 4.0 microg x ml(-1) (DEX group). Another group of 12 children undergoing EGD also received propofol administered by TCI targeting comparable plasma concentrations without dexmedetomidine (control group). We used logistic regression to predict plasma propofol concentrations at which 50% of the patients exhibited minimal response to stimuli (EC50 for anesthesia). Results The EC50 +/- SE values in the control and DEX groups were 3.7 +/- 0.4 microg x ml(-1) and 3.5 +/- 0.2 microg x ml(-1), respectively. There was no significant shift in the propofol concentration-response curve in the presence of dexmedetomidine. Conclusion The EC50 of propofol required to produce adequate anesthesia for EGD in children was unaffected by a concomitant infusion of dexmedetomidine 1 microg x kg(-1) given over 10 min.
Research on faculty orientation programs: Guidelines and directions for nurse educators

The objective of this study was to review the literature for the quality of evidence available regarding faculty orientation programs and to identify practice and research implications. Computerized searches in Medline, Cumulative Index to Nursing and Allied Health Literature, and Educational Resources Information Center, and references cited in articles, were the data sources reviewed. Keywords used in the search were faculty orientation, faculty development, faculty development programs, faculty mentoring, new faculty needs, nursing, teaching, and mentoring. All relevant articles published after 1980 were evaluated. Nineteen reports of research from indexed journals in English relevant to the keywords were reviewed: 14 were quantitative reports, and 5 were qualitative. Characteristics consistently present in the literature were that an orientation program takes place over a prolonged period of time, is incorporated into faculty development plans, creates or fosters an inviting environment, includes information about the tripartite role of the academician, and identifies a specific institutional resource person such as a mentor. Most research to date has been descriptive, consistent with the third level of quality of evidence (III; Marek, 1995). Faculty for whom orientation programs are offered might immerse themselves more effectively in their new environments. Mentoring relationships can ease faculty transitions.
Matrix metalloproteinase-1 gene promoter polymorphism and risk of ovarian cancer

Objective:It has been suggested that the 2G allele of a guanine insertion-deletion promoter polymorphism in the promoter of the matrix metalloproteinase-1 (MMP1) gene may increase susceptibility to ovarian cancer. The 2G allele also has been associated with increased MMP1 expression. We investigated the relationship between the MMP1 polymorphism and ovarian cancer risk in a large population-based, case-control study.Methods:The MMP1 promoter polymorphism was examined in white blood cell DNA from 311 cases and 387 age-and race-matched controls using a radiolabeled polymerase chain reaction assay. In addition, genotyping of the MMP1 polymorphism performed in 42 advanced-stage invasive serous ovarian cancers was compared to their mean relative MMP1 expression from Affymetrix microarrays.Results:The 2G allele frequency did not differ significantly between cases (0.49) and controls (0.48), and the distribution of genotypes was in Hardy-Weinberg equilibrium. Using 1G homozygotes as the reference group, neither ...
Estrogen receptor α and vasopressin in the paraventricular nucleus of the hypothalamus in Peromyscus

Abstract The purpose of this study was to determine the presence of estrogen receptor alpha (ERα) and the relationship between neurons that express ERα and produce vasopressin (AVP) in the paraventricular nucleus of the hypothalamus (PVN) in new world mice of the genus Peromyscus. Brains were collected from male and female Peromyscus californicus, Peromyscus leucopus, Peromyscus maniculatus, and Peromyscus polionotus, and double labeled for the expression of ERα and AVP immunoreactivity (IR). The number of cells expressing ERα-IR and AVP-IR was determined in the medial and posterior region of the PVN. The results indicate that Peromyscus is the first taxonomic group reported to have ERα widely distributed in the PVN, occurring in both medial and posterior regions of the PVN. While estrogen can regulate the production of AVP, AVP and ERα were rarely colocalized. There was, however, a significant inverse relationship between the number of cells that expressed ERα-IR and the number expressing AVP-IR. There were no sex differences in the expression of ERα-IR or AVP-IR.
Application of Gas Adsorption Kinetics — II. A Theoretical Model for Respirator Cartridge Service Life and Its Practical Applications

A previously introduced theoretical model addressing respirator cartridge contaminant breakthrough was further developed in this study. This development involved the introduction of a new theoretical parameter, a, to complement the parameters k′ and τ employed in the initial theoretical approach. The extension of the theory permits the theoretical investigation of the following: (1) the effect of contaminant concentration on breakthrough time; (2) the effect of flow rate on breakthrough time; (3) the influence of contaminant concentration on percentage of breakthrough; and (4) the effect of contaminant concentration on the weight of adsorbed contaminant at a given time. We also compared new theoretical expressions with previously published empirical equations. Utilizing the parameter a, we derived a set of equations of significant practical value. These equations relate the ratio of two contaminant concentrations (one experimental reference concentration and any other concentration of interest) to either ...
Bharatanatyam and Identity Making in the South Asian Diaspora: Culture through the Lens of Occupation

Culture, when defined as those activities that bring meaning to people's lives, has many parallels to occupation, also an exploration of meaning making. This article examines the relationship between culture and occupation through bharatanatyam, a South Indian classical dance. Based on fieldwork carried out in Los Angeles, CA with the Shakti Dance School and Company, this paper explores bharatanatyam's role in racial, ethnic, and religious formation (real and imagined). What does it mean that Lila, a blonde-haired, blue-eyed Caucasian is more Indian than her South Asian American classmates? What is the significance of Sana and Henna, two Pakistani-American Muslim students, choreographing an Islamic song to bharatanatyam when Islam prohibits any form of dancing, let alone its interpretation through a Hindu art form? I demonstrate how bharatanatyam is a cultural occupation. Additionally, in contesting traditional notions of culture as homogenous, cohesive and pure, I reconfigure culture as a creative proces...
CULTIVATION OF HUMAN OSTEOSARCOMA CELL LINES IN SERUM-FREE HORMONE SUPPLEMENTED MEDIUM

Two human osteosarcoma cell lines (TE-85, LM-1) were adapted to grow in serum-free hydrocortisone supplemented medium. Human osteosarcoma associated antigens were detected both on the cell membrane as well as in the concentrated culture medium. TE-85 cells produced bone specific alkaline phosphatase and LM-1 cells produced both bone specific and placental-like alkaline phosphatases when cultured in this medium. Successful proliferation of human osteosarcoma cell lines in serum-free medium is valuable in human osteosarcoma research.
Pharmacologic modulation of protein kinase C isozymes: the role of RACKs and subcellular localisation.

Protein kinase C (PKC) isozymes are highly homologous kinases and several different isozymes can be present in a cell. Each isozyme is likely to mediate unique functions, but pharmacological tools to explore their isozyme-specific roles have not been available until recently. In this review, we describe the development and application of isozyme-selective inhibitors of PKC. The identification of these inhibitors stems from the observation that PKC isozymes are each localised to unique subcellular locations following activation. Inhibitors of this isozyme-unique localisation have been shown to act as selective inhibitors of the functions of individual isozymes. The identification of isozyme-specific inhibitors should allow the exploration of individual PKC isozyme function in a wide range of cell systems.
Effects of collisions on the nonlinear particle dynamics in the magnetotail

The effects of collisional processes on the nonlinear particle dynamics in the magnetotail are considered.A simple collision operator is developed to model the effects of pitch-angle and energy scattering. It is found that the phase space partition persists for up to moderate scattering amplitudes in pitch-angle and energy, and that certain distribution function features are robust even in the presence of large amplitude collisions. It is shown that if the collisions are due to short scale length electrostatic fields, excessively large field amplitudes are required to signifiantly alter the phase space structures and the resulting distribution function features.
Consequences of extended-range interactions in the correlation-induced model of superconductivity in the fullerenes

A proposed model for superconductivity in the alkali-metal-doped fullerenes suggests that electrons pair together because of intramolecular correlation effects [S. Chakravarty and S. Kivelson, Europhys. Lett. 16, 751 (1991)]. With the use of perturbation theory, an effective attractive electron-electron interaction was found for a range of repulsive on-site Hubbard interaction U. We relax the on-site-only restriction by introducing a phenomenological model of statically screened Coulomb interactions and reexamine the original results. We present the consequences of extended interactions on the charged-fullerene ground states, the binding energies, the critical U necessary for pair binding, a nonphononic isotope effect, and the renormalization of the Coulomb pseudopotential parameter ${\mathrm{\ensuremath{\mu}}}^{\mathrm{*}}$. We find that Hund's rule for a fullerene is violated depending on the strength and range of interaction. We determine the phase diagram for pair binding as a function of U (in units of the intrafullerene hopping t) and screening length for the electron filling appropriate for superconducting fullerenes. As the range of interaction increases towards physically reasonable estimates, the required U/t increases, delimiting the model as originally proposed. Our analysis of a nonphononic isotope effect also finds that U/t must be large and the interaction range short in order to describe observed shifts. In contrast, we find the proposed pair-binding model needs extended-range interactions to explain critical superconducting transition temperatures.
A 0.487 throughput limited sensing algorithm

We consider Poisson packet traffic accessing a single-slotted channel. We assume the existence of a ternary feedback per channel slot. We also adopt the limited feedback sensing model where each user senses the feedback only while he has a packet to transmit. For this model we develop a collision resolution algorithm with last come-first served characteristics. The algorithm attains the same throughput as Gallager's algorithm without the latter's full feedback sensing requirement. In addition, it is easy to implement, requires reasonable memory storage, induces uniformly good transmission delays, and is insensitive to feedback errors. In the presence of binary (collision versus noncollision) feedback the algorithm may attain a throughput of 0.4493 .
Inverter characterization for intermittent and peak duty motor drives

This paper investigates inverter time ratings and short-time electrical and thermal limitations in peak duty intermittent-load motor drives. An inverter electro-thermal model is developed and validated to complement prior motor thermal models. The inverter model is used to assess short-time capabilities of IGBT inverters. The results show that the inverter is the thermal bottleneck for short-term ratings in a drive system. A large thermal mass heat sink is shown to increase time ratings. The limit is the semiconductor heat capacity, which is invariant for any duration above a fraction of a second. Analyses are extended to inverter characterization for repetitive duty. For aperiodic duty, an energy-based time rating estimation process is discussed and case studies based on automotive duty and fault duty are presented.
Multimedia object modeling and storage allocation strategies

The improvements in disk speeds have not kept up with improvements in processor and memory speeds. Many techniques have been proposed and utilized to maximize the bandwidths of storage devices. These techniques have proven useful for conventional data, but when applied to multimedia data, they tend to be insufficient or inefficient due to the diversified data types, bandwidth requirements, file sizes and structures of complex objects of multimedia data. In this paper, we discuss the design of an efficient multimedia object allocation strategy that strives to achieve the expected retrieval rates and I/O computational requirements of objects; and also effectively balances the loads on the storage devices. We define a multimedia object model, describe the multimedia object and storage device characteristics, the classification of the multimedia objects according to their I/O requirements, and the fragmentation strategies. We use a bipartite graph model for mapping of fragments to storage devices. A cost function based on a disk utilization per allocated space, the amount of free space, and the bandwidth of a storage device is used to determine the optimal allocation for an object's data.
Glycine and GABA receptors: Molecular mechanisms controlling chloride ion flux

We have been able to show that the three clearly identified atoms common to the inhibitory neurotransmitters glycine and GABA, that we previously hypothesized to serve as attachment points at the glycinergic and gabanergic receptor, can indeed interact through both electrostatic and hydrogen bonding to several amino acids, which have been identified in molecular biological investigations as both present and critical in the physiological functioning of key polypeptides common to these inhibitory receptors. In addition, amino acids also involved in stabilizing the interaction between the antagonists strychnine and R5135 at the glycinergic and gabanergic receptors, respectively, have been shown to fit our complex model. We identify in detail molecular mechanisms to explain how glycine and GABA initiate chloride ion movement from extraneuronal fluid in the synaptic cleft to intraneuronal volume. In addition, we also identify the molecular mechanisms involved in the blocking of chloride ion movement by strychnine at the glycinergic receptor and by R5135 at the gabanergic receptor. We also present two computer-generated color prints, one for the glycine receptor and one for the GABA receptor, which show the quantum mechanically geometry optimized complex formed between receptor side chains, i.e., the part of the amino acids in the polypeptide that interacts with the zwitterionic inhibitory neurotransmitters. These computer-generated color figures also show a) the important electrostatic and hydrogen bonding in these interactions, b) a van der Waals model of this complex to illustrate that no steric repulsions exist, and c) the molecular electrostatic potential energy map showing the electrostatic potentials of neurotransmitter bound to the receptor model. Finally, we show with computer calculations that the pseudo-rings, formed between the positive quanidinium group in arginine and one of the oxygen atoms in the carboxyl group in both glycine or GABA, result in a positive planar region which appears to be involved in a charge-transfer complex with aromatic benzene groups in amino acids such as phenylalanine and tryosine.
Results of the radio-detection experiment HASRA (Hawaii Askaryan in Salt Radio Array) and prospect for UHE neutrino detection in salt

Measurements of radio emission, associated with Ultra High Energy Cosmic Ray particles interaction in a dense dielectric material, provide an effective method of their detection and exploration. The Hawaii Askaryan in Salt Radio Array (HASRA) was built to explore possibility of detection of coherent radio Cherenkov emission in rock salt from interaction of cosmic ray protons and air shower particles. Performance of the detector, the implemented detection techniques, and results of 1 year of measurements of Askaryan effect from CR particles with energy above 100 GeV will be reported. Also potential of the future detectors utilizing radio techniques in rock salt will be discussed.
ADJOINT PROBLEMS IN THE CALCULUS OF VARIATIONS OF MULTIPLE INTEGRALS

Abstract A general theory of adjoint variational problems is formulated for essentially arbitrary Lagrangians involving m independent and n dependent variables, together with the first derivatives of the latter, This approach contains as a special case the theory of Haar [4], in which the Lagrangian may depend solely on the derivatives of a single dependent function of two arguments. Because of the eventual occurrence of possibly incompatible sets of integrability conditions, the basic theory is developed against the background of non-integrable m-dimensional subspaces, which is in sharp contrast to the traditional approach to the calculus of variations. Relatively self-adjoint Lagrangians are defined and completely characterized in terms of an arbitrary Riemannian metric. In the course of the general theory certain geometric object fields are encountered in a very natural manner, some of which had arisen previously in the canonical formalism proposed by Caratheodory [2]. Accordingly the analysis of the p...
Variation in the baseline sister chromatid exchange frequency in human lymphocytes

The utility of the sister chromatid exchange (SCE) assay for human population studies is potentially limited by the variability associated with individual baseline SCE Frequencies. This investigation identifies and quantifies the major sources of preparative and biological variation associated with the determination of baseline SCE frequencies in cultured human lymphocytes. Much of the variation in lymphocyte SCE frequencies is attributable to the amount of bromodeoxyuridine (BrdUrd) available per lymphocyte; the pooled coefficient of variation (CV) over the dose range of 10 to 160 micrometer is about 18%. Other variations in the baseline frequency result from culture-to-culture and slide-to-slide differences. The pooled coefficient of variation among donors is about 10%. The effect of cell-to-cell differences in baseline SCE frequency among donors can be minimized by increasing the number of cells scored per donor. When 20 cells are analyzed per individual the pooled cell-to-cell variation is 9% but when 40 or 80 cells are analyzed it is reduced to 6 and 4% respectively. For a single individual the cell-to-cell coefficient of variation at 100 micrometer BrdUrd is 40.8%. Under our experimental conditions, a 30% increase in SCE frequency between two cohort populations can be detected with a 95% probability at a 5% level of significance when 11 individuals per cohort are studied. For a longitudinal or in vitro dose response study of a single individual, a 50% increase in SCE frequency can be detected with a 95% probability at a 5% level of significance when 25 cells per sample are analyzed. These results indicate the feasibility of applying the SCE bioassay to humans as a measure of environmental stress.
Autoimmunity heats up.

A new study strengthens the view that heat-shock proteins serve as alarm bells for the immune system. Hsp70 appears to influence the immune response to endogenous stimuli, and may serve as a trigger for autoimmunity ( pages 1469–1476 ).
Influence of wettability on the recovery of NAPLs from alluvium

The physicochemical characteristics of five nonaqueous phase liquids (NAPLs) recovered from contaminated alluvial aquifers are presented. The five include two chlorinated degreasing solvents, one chlorinated dry-cleaning solvent and two weathered fuel hydrocarbons. In addition to density, viscosity, and interfacial tensions, the equivalent alkane carbon number (EACN), spreading coefficients and Amott-Harvey and USBM wettability indices with respect to alluvial aquifer materials are used as a means to characterize three of these NAPLs. Experimentally measured spreading coefficients of four of these NAPLs illustrate that field NAPLs can have positive initial spreading coefficients. Furthermore, capillary desaturation curves for two NAPLs with alluvial aquifer material collected from the NAPL zone are presented as an additional and important means to infer the practical implications of the wetting characteristics on the efficacy of NAPL recovery. The results from the wettability and capillary desaturation ex...
Low-Z1/low-Z2 multilayer x-ray optical thin films

We have deposited, via magnetron sputter deposition, multilayer structures comprised of alternating layers of low atomic number materials such as (1) carbon and boron carbide, (2) silicon and boron carbide, (3) silicon and carbon, and (4) aluminum and boron carbide. Layer periods for these materials combinations range from 63.5 to 75 angstrom. These low atomic number multilayers exhibit significant first-order Bragg diffraction of Cu k-alpha radiation. Calculations of the reflectivity performance for multilayers of this composition have been made using a computer code based on the modified Darwin-Prinz theory. Experimental measurements and code predictions are in close agreement. Multilayers of this type may find application in devices requiring ultralow dispersion focusing x-ray optics, such as long focal length focussed beam lines, x-ray microscopes, and x-ray telescopes. Diagnostics for plasma characterization in fusion experiments that are free from L-edge absorption, high transmittance/high resolution beam splitting x-ray optics, and output couplers soft x-ray laser cavities are other possible applications for low-Z1/ low-Z2 multilayers.© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
From Chaos to Clarity: Using the Research Portfolio to Teach and Assess Information Literacy Skills.

This case study reports on the use of Web-based research portfolios in an information literacy course. It offers a model for teaching research skills in a structured and incremental way that can promote student centered learning and facilitate authentic assessment.
Axially deformed skyrmions in a constrained variational approach

Abstract We study the rotational spectrum of axially deformed skyrmions by constraining the radius and the quadrupole moment of the baryon density. The results are compared to a generalized scaling approximation used previously. For purely radial shape changes of the skyrmion the two methods give the same results, while for deformed field configurations small differences are found. These do not upset, however, the general conclusions drawn from the scaling approximation.
4576 Diagnosis of anal sphincter defects using flexible upper gi echoendoscopes.

Introduction: Anal ultrasound, using a rigid, non-endoscopic trans-rectal ultrasound probe, is reported to accurately diagnose anal sphincter defects due to post-obstetrical trauma in the evaluation of fecal incontinence. However most gastroenterologists in the United States who perform EUS use a radial scanning echoendoscope system designed with fiberoptic or video optics to assist in upper GI endosonography, and not a dedicated rigid rectal ultrasound probe system. The purpose of this study was to evaluate the utility of a flexible UGI echoendoscope for diagnosing anal sphincter defects. Methods: Female patients referred for anal sphincter EUS to evaluate fecal incontinence from 11/95-10/99 were included in this retrospective analysis. Anal EUS was performed with either the Olympus GF-UM20 or UM130 radial scanning flexible echoendoscopes. The probe tip was inserted blindly into the anal canal and imaging was performed at 7.5 and 12 MHz without filling the balloon with water. The anterior aspects of the internal (IAS) and external (EAS) anal sphincters were examined for hypoechoic defects, which were reported as percent of circumference. IAS thickness was measured from the posterior aspect. Results: 49 women underwent EUS examinations. The median age was 53 (range 27-61). 38 (78%) had some form of defect detected, with 16 (33%) having both IAS and EAS defects, 20 (41%) isolated EAS defect, 2 (4%) isolated IAS defect, and 11 (22%) no defects. Patients with anterior IAS defects had a median defect of 37% (15-50%). Patients with anterior EAS defects had a median defect of 35% (10-60%). The IAS thickness was a median of 3 mm (1-4 mm). Among the 12 patients who also underwent anal manometry, 9/12 patients had both normal IAS and normal resting anal sphincter pressures. All 12 patients had low anal sphincter squeeze pressures, and 7/12 also had EAS defects. During median follow-up of 12.5 months (2-48), 10/36 (28%) patients with EAS defects underwent surgical sphincteroplasty. Conclusions: 1. EUS using a flexible upper GI echoendoscope can diagnose post-obstetrical anal sphincter defects. 2. Anal EUS information complements anorectal manometry. 3. Most patients with EUS anal sphincter defects do not undergo surgical sphincteroplasty. 4. Anal sphincter EUS performed with a flexible UGI radial scanning echoendoscope can be used in the evaluation of fecal incontinence if rigid anal ultrasound probe equipment is not available. This work was supported in part by a grant from the ASGE/ADHF.
Epistemology in an age of cognitive science

Abstract Like the logical empiricists many contemporary philosophers wish to bring the determinateness of scientific judgment to epistemology. Recent efforts to naturalise epistemology (such as those of the Churchlands) seem to jeopardise the position of epistemology as a normative discipline. Putnam argues that attempts to naturalise epistemology are self‐refuting. My goal is not to defeat the project for the naturalisation of epistemology, but rather to help clarify what it does and does not amount to. I maintain that attempts to completely eliminate the normative will be either forever incomplete or inimical to the progress of science. However, because it is the first horn of this dilemma which will prevail, these considerations do not undermine the importance of future epistemology carefully attending to the results of the relevant sciences.
Experimental Studies of Turbulent Flow in a Porous Circular Tube With Uniform Fluid Injection Through the Tube Wall

G. B. WAlllS.2 I was VelY glad to see this paper because it com­ plements a similar series of experiments with gas extraction from the walls of porous tubes, which is reported in reference [1).3 Many of the results which were obtained in both series of experi­ ments can be compared with each other and can be shown to be approximately consistent with a more general formulation in which the gas velocity normal to the tube walls can be either positive or negative. Pressure Drop The plll'pose of the work which was described in [1] was to ob­ tai n an understanding of the ways in which gas extraction at the walls influences the presslll'e drop in a pipe. An analog was sug­ gested with the Bow of a condensing vapor. The results were in­ terpreted in terms of a Reynolds analogy model in which the wall shear stress was viewed as being caused by a mass 'III which
A 53,000-Da esterase in Strongylocentrotus purpuratus semen is derived from phagocytic cells, not sperm

Semen from the sea urchin Strongylocentrotus purpuratus contains sperm and a small volume (1%) of phagocytes, which often contain degraded sperm. A 53,000-Da esterase in the semen is inhibited by diisopropyl fluorophosphate, but not by soybean trypsin inhibitor (STI). Differential centrifugation experiments now reveal that 70% of the esterase activity (formerly described as a sperm protease precursor; Levine and Walsh, 1980) is associated with the phagocytes, which sediment more rapidly than the sperm. The 53K esterase is also present in spawned ovaries and testes. However, as previously reported, the sperm do contain an STI-inhibitable protease as shown by the digestion of [14C]lysozyme. Intact sperm exhibit STI-inhibitable hydrolytic activity toward N-α-[3H]benzoyl-l-arginine ethyl ester [3H]BAEE), but crude homogenates do not until they are extracted at pH 2.5 and fractionated by ion exchange chromatography. Although not obtained in pure form, the protease activity appears to migrate with a molecuar weight of 20,000 (gel filtration). The protease and the esterase differ markedly in acid stability. After preincubation at pH 2.5 the protease still hydrolyzes [3H]BAEE, while the esterase is irreversibly inactivated. This last observation may explain an earlier interpretation (A. E. Levine and K. A. Walsh, 1980, J. Biol. Chem. 255, 4814–4820) that the 53K enzyme dissociated at pH 2.5 into two unequal subunits, one of which was the active protease. Since it has been shown that the contaminating phagocytes contribute most of the esterase activity of the semen, the occurrence of even a small number of nonsperm cells cannot be ignored in future investigations of sperm enzymes.
Lipid-polyethylene glycol interactions: II. Formation of defects in bilayers

The kinetic properties of L-leucine transport across the human red blood cell membrane was analyzed according to the simple pore and carrier theory of Lieb and Stein (Biochim. Biophys. Acta, 1974, 373: 165-177 and 178-196) at 25 degrees C, pH 7.4. Several methods were used in order to obtain a thorough kinetic description of L-leucine transport. A rejection of the simple pore model was suggested from the result of zero-trans influx and zero-trans and equilibrium-exchange efflux experiments. Several predictions from the simple carrier model, based on the requirement of consistency among different kinetic parameters, were tested in infinite experiments, i.e. experiments performed at a high concentration of substrate at one of the faces of the membrane. The simple pore model was rejected, but no crucial evidence against a simple carrier model, which displays symmetric properties at 25 degrees C, was found in the concentration range considered (0.002-68 mM). The relative magnitudes of the rate constants of the translocation process are discussed, and it is concluded (a) that both the dissociation and translocation of carrier-complex is faster than the translocation of the empty carrier, (b) that no translocation step is rate determining, and (c) that the carrier-complex is equally distributed across the membrane at equilibrium. The present work provides a unique example of a carrier-mediated transport mechanism which displays symmetric properties. L-leucine transport in red blood cells may be a convenient system for studying molecular mechanisms of facilitated transport.
Anthropometric comparison of mentally retarded males with and without the fragile X syndrome.

An anthropometric survey of 41 variables (weight, height, 10 linear, 4 breadth, 22 craniofacial, 2 skinfold, and testicular volume), including multivariate discriminant analysis, was undertaken on 110 mentally retarded males (39 with and 71 without the fra(X) syndrome). The mean Z scores of the fra(X) syndrome males fell between - 2.00 and 8.38 for bizygomatic diameter and testicular volume, respectively, and the range of the mean Z scores of the non-fra(X) males was from - 2.64 to 2.26 for hand breadth and testicular volume, respectively. There was a statistically significant difference (P < .05) between fra(X) and non-fra(X) males for 18 measurements (weight, height, 7 linear, 2 breadth, 5 craniofacial, 1 skinfold, and testicular volume), with the greater measurements (excluding bizygomatic diameter) found in fra(X) males. Sitting height, knee-buttock length, middle finger length, and hand length were negatively correlated (P < .05) with age, whereas bizygomatic diameter, ear length, and ear width were positively correlated (P < .05) with age and head circumference, head length, and outer canthal distance were positively correlated (P < .05) with fra(X) chromosome expression in the fra(X) males. Triceps and subscapular skinfold thicknesses were negatively correlated (P < .05) with age, whereas ankle breadth, ear length, ear width, and nose length were positively correlated (P < .05) in the non-fra(X) males. Discriminant analysis of 34 fra(X) and 71 non-fra(X) males resulted in a discriminant function based on 6 of 17 anthropometric variables and age. In the discriminant analysis, patients with the fra(X) syndrome were distinguished from mentally retarded males without the fra(X) syndrome at an overall correct classification rate of 97.1% in our sample. The 6 anthropometric variables in the discriminant function were the Z scores representing testicular volume, ear width, head breadth, bizygomatic diameter, hand breadth, and hand length. Additional research is needed to test the usefulness of these variables in screening mentally retarded males for the fra(X) syndrome.
Intense laser ionization of transiently aligned CO

We have measured the ionization rate for CO molecules exposed to intense $30\phantom{\rule{0.3em}{0ex}}\mathrm{fsec}$ $780\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$ laser pulses as a function of the angle between the molecular and laser polarization axes. Nonionizing, $70\phantom{\rule{0.3em}{0ex}}\mathrm{fsec}$ laser pulses are used to coherently prepare the molecules, preferentially aligning them for the strong-field ionization experiments. We find a 2:1 ionization-rate ratio for molecules aligned parallel or perpendicular to the ionizing field.
Formation of doubly excited two-electron ions during F8++He, F8++Ne, and F8++Ar collisions.

High-resolution x-ray spectroscopy has been used to measure the cross sections for forming doubly excited F/sup 7 +/ ions in the 2s2p and 2p/sup 2/ configurations following F/sup 8 +/+He, F/sup 8 +/+Ne, and F/sup 8 +/+Ar collisions over a projectile-energy range of 13--31 MeV. The intermediate states are found to be formed predominantly by projectile-electron excitation coupled with target-to-projectile electron transfer to an excited state during a single ion-atom collision. This process is termed nonresonant transfer and excitation (NTE) (P. L. Pepmiller et al., IEEE Trans. Nucl. Sci. NS-30, 1002 (1983)). A competing process for formation of the doubly excited states is resonant transfer and excitation (RTE) (D. Brandt, Phys. Rev. A 27, 1314 (1983)), a process analogous to dielectronic recombination. Although the projectile energies spanned the region where resonant transfer and excitation are expected to maximize, no resonant contribution to the measured cross sections could be positively identified for the collision systems studied here. This result is consistent with the relative magnitudes of the theoretical cross sections for resonant and nonresonant transfer and excitation presented in the present work.
Microtomography at GeoSoilEnviroCARS

A facility for x-ray computed microtomography (CMT) is operating as a national user facility for earth and environmental sciences research on the bending magnet beamline at the GeoSoilEnviroCARS sector at the Advanced Photon Source (APS). The APS bending magnet has a critical energy of 20 keV, and thus provides high flux at photon energies up to 100 keV, making it well suited to imaging a wide range of earth materials up to several cm in size. The beamline is equipped with a Si (111) double-crystal monochromator covering the energy range from 5 to 70 keV with beam sizes up to 50mm wide and 6mm high. The transmitted x-rays are imaged with a single crystal YAG scintillator, a microscope objective and a 1300x1030 pixel 12-bit 5MHz CCD detector. The maximum spatial resolution is under 2 microns in both the transmission radiographs and the reconstructed slices. Data collection times for full 3-D datasets range from 5-60 minutes. This facility has been used for a wide range of studies, including multiphase fluids in porous media, high-pressure studies, meteorites, and hyper-accumulating plants.
A CONVENIENT ONE-POT PREPARATION OF N-SUBSTITUTED HYDROXYLAMINES

(1985). A CONVENIENT ONE-POT PREPARATION OF N-SUBSTITUTED HYDROXYLAMINES. Organic Preparations and Procedures International: Vol. 17, No. 4-5, pp. 254-256.
Studies of Methods of Determining Capillary Fragility1

INTRODUCTION In a previous study of capillary fragility in 190 white male subjects, the authors reported that age of subject and time of test exert some influence on the result of the Rumpel-Leede test (1). One hundred of these same individuals were also tested with a Petechiometer® f which has been advocated as a simple, accurate and readily available suction (or negative pressure) type of instrument (2, 3). The results obtained with the Petechiometer are discussed in the present report.
Optical design of the SNS liquids reflectometer

Barring a monumental failure of design execution or of performance estimation, the liquids reflectometer at the SNS will provide unprecedented capabilities for the study of liquid and solid surfaces. Design of the instrument is well underway and procurement of the guide components has begun. Nuetrons from a coupled 20-K supercritical hydrogen moderator will be delivered via a multi-channel supermirror bender and tapered guide onto either a horizontal or tilted surface. Collimating slits select the beam incident angle from a 0-5° vertical intensity distribution provided by optics. With the SNS running at 2 MW, the instrument will be able to accumulate a complete specular reflectivity scan from D2O (R 0.5 a-1) in less than 10 minutes. We will describe the optical design of the SNS liquids reflectometer, compare it with a conventional instrument, and estimate its time resolution for a model kinetic system.
Allosteric Models for Cooperative Polymerization of Linear Polymers

In the cytoskeleton, unfavorable nucleation steps allow cells to regulate where, when, and how many polymers assemble. Nucleated polymerization is traditionally explained by a model in which multistranded polymers assemble cooperatively, whereas linear, single-stranded polymers do not. Recent data on the assembly of FtsZ, the bacterial homolog of tubulin, do not fit either category. FtsZ can polymerize into single-stranded protofilaments that are stable in the absence of lateral interactions, but that assemble cooperatively. We developed a model for cooperative polymerization that does not require polymers to be multistranded. Instead, a conformational change allows subunits in oligomers to associate with high affinity, whereas a lower-affinity conformation is favored in monomers. We derive equations for calculating polymer concentrations, subunit conformations, and the apparent affinity of subunits for polymer ends. Certain combinations of equilibrium constants produce the sharp critical concentrations characteristic of cooperative polymerization. In these cases, the low-affinity conformation predominates in monomers, whereas virtually all polymers are composed of high-affinity subunits. Our model predicts that the three routes to forming HH dimers all involve unstable intermediates, limiting nucleation. The mathematical framework developed here can represent allosteric assembly systems with a variety of biochemical interpretations, some of which can show cooperativity, and others of which cannot.