cssi/SciSciGPT-SciSciNet huggingface dataset:
Progressive bovine sperm separation using parallelized microchamber-based microfluidics

Motility is one of the most important factors in sperm migration toward an egg. Therefore, sperm separation based on motility might enhance sperm selection for infertility treatments. Conventional centrifugation-based methods increase the risk of damage to sperm cells. Microfluidic systems, on the other hand, can sort sperm in a less intrusive way, but their efficiency and throughput still needs improvement, especially in low-concentration samples (oligozoospermia). Here, a microchamber-based microfluidic platform is demonstrated that can separate progressively motile sperm from non-viable sperm and debris, and trap nonprogressive sperm in microchambers. This platform can be operated in a short period of time (<10 min) with an excellent degree of controllability with no sample preparation. Sperm were screened in a 384-microchamber platform. The mean average-path velocity of the motile sperm in the collected sample increased significantly, from 57 ± 10 μm s-1 in the raw semen sample to 81 ± 13 μm s-1. The DNA Integrity of the separated sperm showed 20% improvement over the raw sample which indicated that separated sperm were of higher quality. We began with a 22.5 μL raw bovine sperm sample which had a concentration of 8.5 million sperm per milliliter (M mL-1) with 38% motility. After separation, the concentration of the collected sperm was 2.1 M mL-1 with a motility rate of 90%. This corresponds to a 75% retrieval efficiency and the selection of approximately 5.2 × 104 progressively motile spermatozoa. Our results show that the microchamber depth does not affect the residence time of motile sperm; therefore, it is possible to inspect higher sample volumes within the same time frame. This microfluidic platform may provide an easy-to-implement solution for high-throughput, robust, and efficient, collection of progressive sperm with the DNA integrity needed for assisted reproductive technologies (ARTs). However, further studies are necessary to show the implications of this method in human cases.
The Ghana Reader: History, Culture, Politics edited by Kwasi Konadu and Clifford C. Campbell

Konadu, Kwasi and Clifford C. Campbell, eds. The Ghana Reader: History, Culture, Politics . Durham, NC: Duke University Press, 2016. Review by Kwaku Nti.
Extending the reach of Lagrangian analysis in turbulence

The hypothesis in the classical Kolmogorov picture of turbulence with perhaps the most far-reaching consequences is that of universality, the notion that small-scale turbulence dynamics are independent of the way the turbulence was generated. The assumption of universality can be evaluated by comparing measurements taken in many kinds of flows. However, up to now the range of flows that can be used to study universality from a Lagrangian viewpoint has been highly constrained, because large-scale Eulerian inhomogeneity manifests as Lagrangian non-stationarity. The recent work of Viggiano et al. (J. Fluid Mech., vol. 918, 2021, A25) significantly extends this range by showing how the dynamics along Lagrangian trajectories can be continuously renormalised using local Eulerian scales, at least in flows whose development is self-similar. They demonstrate their results on a turbulent jet, a classical flow that is well studied from the Eulerian perspective, though not in a Lagrangian sense. Their work provides an exciting roadmap for expanding the scope of Lagrangian analysis of turbulent flows.
Celecoxib Colorectal Bioavailability and Chemopreventive Response in Patients with Familial Adenomatous Polyposis.

Why celecoxib exerts chemopreventive activity in only some familial adenomatous polyposis (FAP) patients remains poorly understood. We conducted a phase II clinical study to identify potential predictive biomarkers for celecoxib chemopreventive activity in FAP. Twenty-seven patients with FAP completed a 6-month oral course of 400 mg of celecoxib twice a day; they underwent colonoscopies before and after celecoxib treatment to assess colorectal polyp tumor burden and to obtain normal and polyp colorectal biopsies to measure celecoxib, 13-S-hydroxyoctadecadienoic acid (13-HODE), 15-HETE, 12-HETE, and LTB4 levels by LC/MS-MS. Celecoxib levels in sera from those patients were also measured before treatment and after 2, 4, and 6 months of treatment. Nineteen of the 27 patients experienced a response to celecoxib, with a ≥ 28% reduction of colonic polyp burden on the basis of a reproducible quantitative assessment of colonoscopy results. Celecoxib levels were significantly lower in polyp tissues than in normal colorectal tissues. Celecoxib levels in sera and normal colorectal tissues were correlated in patients who experienced a response to celecoxib but not in those who did not. Among the measured lipoxygenase products, only 13-HODE levels were significantly lower in polyp tissues than in normal tissues. Our findings demonstrate the differential bioavailability of celecoxib between normal and polyp tissues and its potential effects on clinical response in patients with FAP. PREVENTION RELEVANCE: This study evaluated potential predictive biomarkers for celecoxib chemopreventive activity in patients with FAP. Our findings demonstrated the differential bioavailability of celecoxib between normal and polyp tissues and its potential effects on clinical chemopreventive response in patients with FAP.
Revisiting the natural resource curse: A cross-country growth study

This paper revisits the original natural resource curse study conducted by Sachs and Warner to investigate the relationship between natural resource dependence and per capita growth in recent data ...
Time dependent accessibility

Abstract Many place based accessibility studies ignore the time component. Relying on theoretical frameworks that treat distance between two fixed points as constant, these methods ignore the diurnal and seasonal changes in accessibility. Network distances between two nodes are dependent on the network structure and weight distribution on the edges. These weights can change quite frequently and the network structure itself is subject to modification because of availability and unavailability of links and nodes. All these reasons point to considering the implications of volatility of accessibility of a place. Furthermore, opportunities have their own diurnal rhythms that may or may not coincide with the rhythms of the transportation networks, impacting accessibility. Using the case of transit, where all these features are readily apparent simultaneously, I demonstrate the volatility in accessibility for two counties in North Carolina. Significant diurnal changes are observed in quarter of the locations and in the rest the changes are minimal mostly because of low levels of transit accessibility. I argue not for minimizing the volatility, but for acknowledging its impacts on mode choices, location choices and therefore on spatial structure of cities.
Low-frequency noise spectrum measurements of mid-wave infrared nBn detectors with superlattice absorbers

Type-II Strained Layer Superlattice (T2SLS) infrared photodetectors have been in ongoing development over the last decade with the goal of achieving lower dark currents and higher operating temperatures when com- pared to mercury cadmium telluride (MCT) detectors. The theoretically longer Auger recombination lifetime of T2SLS has potential to lower dark current but the presence of Shockley-Read-Hall (SRH) defects limits the recombination lifetime far below the Auger-limit. In order to reduce SRH-recombination, unipolar barriers have been incorporated into the energy bands of T2SLS materials in different forms, such as nBn, to improve performance. Here, noise spectra are presented for varyingly sized, near 90% quantum efficiency, nBn mid-wave infrared (MWIR) detectors with superlattice absorbing layers grown by MBE. Noise spectrum measurements are used to evaluate device performance and reveal mechanisms contributing to low frequency noise that often exceeds predictions based on ideal shot noise. Voltage and temperature dependent noise spectra were taken using an external trans-impedance amplifier with an internal, cooled impedance converter and feedback resistor.
Fresh shallow valleys in the Martian midlatitudes as features formed by meltwater flow beneath ice

Significant numbers of valleys have been identified in the Martian midlatitudes (30–60°N/S), spatially associated with extant or recent ice accumulations. Many of these valleys date to the Amazonian, but their formation during these cold, dry epochs is problematic. In this study, we look in detail at the form, distribution, and quantitative geomorphology of two suites of these valleys and their associated landforms in order to better constrain the processes of their formation. Since the valleys themselves are so young and thus well preserved, uniquely, we can constrain valley widths and courses and link these to the topography from the Mars Orbiter Laser Altimeter and High-Resolution Stereo Camera data. We show that the valleys are both qualitatively and quantitatively very similar, despite their being >5000 km apart in different hemispheres and around 7 km apart in elevation. Buffered crater counting indicates that the ages of these networks are statistically identical, probably forming during the Late Amazonian, ~100 Ma. In both localities, at least tens of valleys cross local drainage divides, apparently flowing uphill. We interpret these uphill reaches to be characteristic of flow occurring beneath a now absent, relatively thin (order 101–102 m), regionally extensive ice cover. Ridges and mounds occasionally found at the foot of these valley systems are analogous to eskers and aufeis-like refreezing features. On the basis of their interaction with these aufeis-like mounds, we suggest that this suite of landforms may have formed in a single, short episode (perhaps order of days), probably forced by global climate change.
The influence of amino acids on iron absorption.

A series of experiments were devised to determine the effect of various amino acids upon the absorption of iron from the gastrointestinal tract. This was done by introducing single amino acids and Fe59 into isolated loops of small intestine and measuring the serum for radioactivity and the uptake of Fe59 by the liver. It was found that under the conditions of the experiments all of the amino acids studied effected an increase in the serum iron and iron deposition in the liver.
A methodology for long range prediction of air transportation

A framework and methodology for long term projection of demand for aviation fuels is presented. The approach taken includes two basic components. The first was a new technique for establishing the socio-economic environment within which the future aviation industry is embedded. The concept utilized was a definition of an overall societal objective for the very long run future. Within a framework so defined, a set of scenarios by which the future will unfold are then written. These scenarios provide the determinants of the air transport industry operations and accordingly provide an assessment of future fuel requirements. The second part was the modeling of the industry in terms of an abstracted set of variables to represent the overall industry performance on a macro scale. The model was validated by testing the desired output variables from the model with historical data over the past decades.
Order-sorted parameterization and induction

Parameterization is one of the most powerful features to make specifications and declarative programs modular and reusable, and our best hope for scaling up formal verification efforts. This paper studies order-sorted parameterization at three different levels: (i) its mathematical semantics; (ii) its operational semantics by term rewriting; and (iii) the inductive reasoning principles that can soundly be used to prove properties about such specifications. It shows that achieving the desired properties at each of these three levels is a considerably subtler matter than for many-sorted specifications, but that such properties can be attained under reasonable conditions.
Transport of Gas and Solutes in Permeable Estuarine Sediments

Abstract : The long-term goals of this project are to 1) quantify gas bubbles and their composition in shallow nearshore marine sand and 2) to assess the role of gas bubbles in shallow sandy coastal sediment for the transport of solutes through the sand and sediment-water exchange of matter. Due to their compressibility, gas bubbles embedded in shallow water sediments cause interstitial water oscillations under passing surface gravity waves, and these oscillations provide a mechanism for enhanced solute dispersion and flux. 1) To detect gas bubbles and in coastal and estuarine sand deposits and to assess temporal and spatial distribution of sedimentary bubbles in sublittoral beds including sands inhabited by microphytobenthos and seagrass. 2) To quantify the size range and composition of the gas bubbles in the sediment and the overlying water. 3) To determine the volume change and migration velocities of interstitial bubbles and the links to pressure oscillations 4) To assess dispersion and transport of solutes caused by bubble volume change and migration under different pressure conditions. Measurement of gas release volumes from the sediments using benthic chambers and gas analysis. Determination of gas composition. Measurement of gas bubble dimensions and distribution. Mapping of the spatial and temporal distribution of high sedimentary photosynthetic production and oxygen supersaturation and depletion as potential sites for free gas development. Determination of the rate of gas bubble release from the sediment through quantification of noble gas depletion in the pore water. Determination of gas content, distribution and migration in the surface sediment. Measurement of solute transport caused by bubble compression and migration.
Dynamic path following: a new control algorithm for mobile robots

A new algorithm for the control of wheeled mobile robots called dynamic path following is presented. This algorithm regulates the motion of the mobile robots to desired geometric paths as opposed to desired trajectories which are given as time histories in conventional trajectory tracking algorithms. The desired trajectory for the dynamic path following algorithm is parameterized by a convenient geometrical parameter (e.g., arc length of the path). The algorithm is designed by using a nonlinear feedback for input-output linearization and decoupling. The performance of this new algorithm is compared with that of the trajectory tracking algorithm and is evaluated under different initial conditions as well as in the presence of various uncertainties using computer simulations. >
Two Problems for Proportionality about Omissions

Theories of causation grounded in counterfactual dependence face the problem of profligate omissions: numerous irrelevant omissions count as causes of an outcome. A recent purported solution to this problem is proportionality, which selects one omission among many candidates as the cause of an outcome. This paper argues that proportionality cannot solve the problem of profligate omissions for two reasons. First: the determinate/determinable relationship that holds between properties like aqua and blue does not hold between negative properties like not aqua and not blue. Negative properties are those at stake in omissive causation. Second: proportionality misconstrues the nature of the problem to be solved.
Heidegger's Topical Hermeneutics: the Sophist Lectures

L'A. defend la these selon laquelle l'hermeneutique de Heidegger, mise en oeuvre dans ses lectures du «Sophiste» de Platon, offre un moyen de depasser le conflit entre objectivisme et relativisme portant sur le caractere universel du critere de verite. Ayant pour objet une verite situee, l'hermeneutique heidegerienne definit la topicalite comme fidelite aux choses en soi et comme historicite authentique
Physical and Linkage Mapping of Human Chromosome 17 Loci to Dog Chromosomes 9 and 5

Genome mapping in the dog is in its early stages. Here we illustrate an approach to combined physical and linkage mapping of type 1 anchor (gene) loci in the dog using information on syntenic homology from human and mouse, an interbreed cross/backcross, and a strategy for isolation of dog genomic clones containing both gene-specific sequences and simple sequence repeat polymorphisms. Eleven gene loci from human chromosome 17q (HSA17q) were mapped to the centromeric two-thirds of dog chromosome 9 (CFA9), an acrocentric chromosome of medium size: P4HB, GALK1, TK1, GH1, MYL4, BRCA1, RARA, THRA1, MPO, NF1, and CRYBA1. Eight of these were also positioned on a linkage map spanning 38.6 cM. Based on combined fluorescence in situ hybridization and linkage mapping, the gene order on CFA9 is similar to that of the homologous genes on HSA17q and mouse chromosome 11 (MMU11), but in the dog the gene order is inverted with respect to the centromere. Canine loci, GALK1, TK1, GH1, MYL4, THRA1, and RARA constitute a closely linked group near the centromeric end of CFA9, spanning a genetic distance of only 4.7 cM. Canine NF1 and CRYBA1 lie distally, near the lower border of the Giemsa band adjacent to the distal one-third of CFA9. NF1 and CRYBA1 are loosely linked to the more centromeric group (31.2 cM). No HSA17 genes were found on the telomeric one-third of CFA9. Painting of dog chromosomes with a human whole chromosome 17 probe showed hybridization with only the proximal two-thirds of CFA9, consistent with the conclusion that the distal one-third corresponds to a segment or segments of other human chromosomes. Two loci, GLUT4 and PMP22, located on HSA17p, were mapped by FISH to dog chromosome 5 in a region also identified by the whole human chromosome 17 paint, indicating disruption of HSA17 syntenic homology at the centromere.
Effects of testosterone on the behavioral response to arginine vasopressin microinjected into the central gray and septum

Arginine vasopressin (AVP) plays an important role in the control of a gonadal hormone-dependent communicative behavior in the Syrian hamster (Mesocricetus auratus) called flank marking. Previous studies have shown that gonadal hormones alter the amount of flank marking stimulated by the microinjection of AVP into the medial preoptic area-anterior hypothalamus (MPOA-AH). The purpose of the present study was to determine if testicular hormones alter the amount of flank marking stimulated by the microinjection of AVP into two other sites involved in the control of flank marking, the lateral septum-bed nucleus of the stria terminalis (LS-BNST) and the central gray. The data of the present study indicate that testicular hormones may influence the amount of AVP-stimulated marking in the central gray and LS-BNST; however, these effects are subtle and appear to occur primarily at high concentrations of AVP. When taken together with previous studies, these data indicate that gonadal hormones have greater effects on AVP-stimulated marking in the MPOA-AH than in the LS-BNST or central gray.
Transitional and Turbulent Flow Modeling in a Tesla Valve

A Tesla valve is a fluidic dioide that may be used in a variety of mini/micro channel applications for passive flow rectification and/or control. The valve’s effectiveness is quantified by the diodicity, which is primarily governed by the incoming flow speed, its design and direction-dependent minor losses throughout its structure during forward and reverse flows. It has been previously shown that the Reynolds number at the valve inlet is not representative of the entire flow regime throughout the Tesla structure. Therefore, pure-laminar solving methods are not necessarily accurate. Local flow instabilities exist and exhibit both transitional and turbulent characteristics. Therefore, the current investigation seeks to identify a suitable RANS-based flow modeling approach to predict Tesla valve diodicity via three-dimensional (3D) computational fluid dynamics (CFD) for inlet Reynolds numbers up to Re = 2,000. Using ANSYS FLUENT (v. 14), a variety of models were employed, including: the Realizable k-e, k-kL-ω and SST k-ω models. All numerical simulations were validated against available experimental data obtained from an identically-shaped Tesla valve structure. It was found that the k-e model drastically under-predicts experimental data for the entire range of Reynolds numbers investigated and cannot accurately model the Tesla valve flow. The k-kL-ω and SST k-ω models approach the experimentally-measured diodicity better than regular 2D CFD. The k-kL-ω demonstrates exceptional agreement with experimental data for Reynolds numbers up to approximately 1,500. However, both the k-kL-ω and k-ω SST models over-predict experimental data for Re = 2,000.Copyright © 2013 by ASME
Phenotypic Expression of Transformation: Induction in Cell Culture by a Phorbol Ester

A biologically potent, tumor-promoting phorbol ester from Croton tiglium L. induces the appearance of transformed clones in a population of contact-inhibited fibroblasts of the mouse cell line 3T3. Mixed populations of cells with 10,000 3T3 cells and 100 virus-transformed cells were exposed to the phorbol ester and, in comparison with untreated cells, showed a marked increase in the numbers of transformed clones that grew. Exposure of 3T3 cultures to the carcinogen 7,12-dimethylbenz(a)anthracene alone or prior to exposure to the phorbol ester did not cause any increase in the number of transformed clones.
Direct measurement of the electrogyratory effect in bismuth silicon oxide

A direct measurement of the electrogyratory effect in bismuth silicon oxide is performed at wavelengths of 633, 543, and 442 nm. We experimentally measured the electrogyratory effect separately from the electro-optic effect. For externally applied electric fields ranging from 0 to 60 kV/cm, the contribution due to the electrogyratory effect is found to be negligible with respect to the contribution due to the electro-optic effect. Since devices employing bismuth silicon oxide typically require applied electric fields in this range, the electric field dependence of the rotary power is shown not to perturb the desired operation.
ENDOGENOUS MECHANISMS OF SENSORY MODULATION

We provide evidence supporting the idea that the relationship between tissue damage, or the threat of tissue damage, and the response to such stimuli is variant and dependent on neuronal networks by which attentional, emotional and cognitive components of pain experience activate endogenous descending modulatory systems. Most previous studies have focused on responses to transient noxious stimuli with little information on the influence of descending modulation on behavioral responses to persistent pain and hyperalgesia after tissue or nerve injury. Utilizing correlative behavioral and neuronal studies we have demonstrated that (1) behavioral context modulates neuronal activity in nociceptive and non-nociceptive somatosensory pathways, supporting the hypothesis that responses in these pathways are not immutable; (2) descending modulation influences behavior and neuronal activity at spinal cord levels after inflammation and persistent pain; and (3) there are descending facilitatory as well as inhibitory influences on behavior and spinal cord neuronal activity that may impact on persistent pain particularly of deep muscle and visceral origin. Cortical as well as subcortical pathways are available by which dorsal horn activity can be modulated by attentional, motivational and cognitive factors. It appears that the same neuronal mechanisms in the forebrain and brain stem are available for behavioral modulation in a learned task involving the threat of tissue damage (transient noxious stimuli) as are available in the development and amplification of persistent pain produced by inflammation. These parallel brain mechanisms emphasize the saliency of pain experience as an important learned behavior for the survival of the organism, similar to sequential goal-directed behaviors in an operant task.
"Stop and go" kinetics of receptor movements induced by anti-Ig or antigen on individual lymphocytes.

Abstract Serial observations were conducted on the time course of surface immunoglobulin (Ig) redistribution (capping) on individual mouse spleen lymphocytes. Capping of surface Ig by anti-Ig fluorescein and also antigen-induced capping of receptors on specific sheep erythrocyte antigen-binding cells were observed and the times required for individual cells to clear 90 and 180 ° of their circumference were recorded. There were striking differences between individual cells in both the onset and duration of receptor movements. Although the number of cells achieving complete clearing of first and second quadrants in successive time intervals declined, there was no correlation between the time required by a cell to clear the first quadrant and the time required by the same cell to clear the second quadrant. Thus, instead of observing gradual progressive migration of marker toward one pole of each individual cell at a rate resembling that of the whole population, we observed grossly discontinuous receptor movements, characterized by brief major shifts in receptors followed by a period of relative stability. Capping is thus viewed as a series of discrete contractile events related to the activity of membrane-associated cytoskeletal elements rather than a manifestation of “membrane flow”.
THE EFFECT OF NUMBER OF CHOICE ALTERNATIVES IN THE TAFFEL TECHNIQUE UPON RATE OF CONDITIONING AND AWARENESS IN CHILDREN.

Summary Once again it has been demonstrated that children's verbal behavior changes as a function of social approval. There is no indication, however, that the number of choice-alternatives (within the limits of two to six alternatives) in the experimental task has any effect upon the rate of change or upon the frequency of Ss verbalizing awareness. It appears that more children can or will verbalize awareness of the response-reinforcement contingency when an expanded and more suggestive inquiry is used. A greater rate of change in verbal behavior was found in Ss who do verbalize awareness as compared to those who do not.
Inhibition of glucose-induced insulin secretion by indomethacin and sodium salicylate in the fetal lamb.

Abstract The modulation of fetal insulin secretion by prostaglandins was studied with the aid of the prostaglandin synthesis inhibitors indomethacin and sodium salicylate in 10 chronically catheterized fetal lambs. Glucose-induced fetal insulin secretion was inhibited within 60 minutes by preinjection of either indomethacin or sodium salicylate in the fetal lambs. In the sodium salicylate experiments a significant (p
Contact Analysis of Multilayered Elastic/Plastic Solids With Rough Surfaces for Decreasing Friction and Wear

A numerical three-dimensional contact model is presented to investigate the contact behavior of multilayered elastic-perfectly plastic solids with rough surfaces. The surface displacement and contact pressure distributions are obtained based on the variational principle with fast Fourier transform (FFT)-based scheme. Von Mises yield criterion is used to determine the onset of yield. The effective hardness is modeled and plays role when the local displacement meet the maximum displacement criterion. Simulations are performed to obtain the contact pressures, fractional total contact area, fractional plastic contact area, and surface/subsurface stresses. These contact statistics are analyzed to study the effects of the layer-to-substrate ratios of stiffness and hardness, surface roughness, and layers thickness of rough, two-layered elastic/plastic solids. The results yield insight into the effects of stiffness and hardness of layers and substrates, surface roughness, and applied load on the contact performance. The layer parameters leading to low friction, stiction, and wear are investigated and identified.Copyright © 2005 by ASME
The Relevance of Relationship Satisfaction and Continuation to the Gender Symmetry Debate

In prior research, Ackerman and Field (2011) found that intimate partner violence (IPV) affects the relationship satisfaction of females more than the relationship satisfaction of males. The current research replicated those findings on a different sample of men and women. In addition to confirming past findings, it also found that gendered patterns in IPV differed substantially for current versus former relationships. Subsequent analyses indicated that gendered differences in whether relationships are continued or terminated after IPV apparently explained these patterns. The current analyses illustrate how relationship continuation differences across gender can produce sample selection biases that substantially affect conclusions about whether partner violence is perpetrated equally by men and women. More specifically, the results of this research are consistent with the conclusion that female IPV victims are more likely than are male victims to become dissatisfied with aggressive opposite-sex partnerships and subsequently terminate their aggressive relationships. For this reason, research that relies only upon the analysis of current relationships will underestimate the amount of partner violence committed by men.
Developing a Broadband Amplifier for Analysis of DNA Structural and Molecular Characteristics

The recent emergence of DNA-based diagnostics increases the need for rapid DNA sequencing technologies. One method to achieve this is to pass DNA through a nanopore, recording the trans-membrane current with a low-noise current amplifier. The challenge presented in this method is that the bandwidth of commercially available current amplifiers is limited to 100kHz, which is not fast enough to resolve the signals present in DNA sequencing. To overcome this problem, researchers have developed a custom amplifier that has reached a bandwidth of approximately 1MHz, being able to reveal additional information during the DNA translocation events through a nanopore.We will demonstrate a design of a custom amplifier that offers a wider bandwidth than the current designs, enabling the study of DNA translocation without the need to limit the speed of translocation. In addition, an amplifier with a bandwidth larger than 1MHz allows discoveries to be made about information that might be present in a higher range of frequencies, enabling measurements at a higher time resolution than what was previously possible. The amplifier will be designed to allow direct integration of a micro- or nanopore sensing area on the same physical substrate, eliminating the need for external electrode wiring. The outcomes from this research open up the possibility of an integrated high-speed DNA sequencer chip enabling rapid disease diagnostics.
Charge transfer and ionization in low-energy Ar q + + Ne collisions

A secondary-ion recoil source was used to study charge transfer and ionization in collisions of ${\mathrm{Ar}}^{q+} (2\ensuremath{\le}q\ensuremath{\le}9)$ on Ne at projectile energies between 100 and 1100 eV per projectile charge. Two experimental methods are presented. With the first one we measure cross sections for electron capture by detecting both the initial and final charge states of the Ar ions. With the second method we measure, in addition to those parameters, the charge state of the Ne ions after the reaction. This three-parameter method allows us to distinguish among various competing reaction mechanisms and to measure cross sections for single- and multiple-electron capture, ionization, and transfer ionization. We find that the cross sections for ionization without simultaneous capture are negligibly small, whereas those for transfer ionization are quite important in several cases.
Breakdown of chromium oxide scales in sulfur-containing environments at elevated temperatures

Structural Fe-Cr-Ni alloys may be rapidly degraded in oxygen-sulfur mixed-gas environments at elevated temperatures unless protective oxide scales can be formed and maintained. The breakaway corrosion process was examined in model alloys of Fe-25wt.% Cr-20wt.% Ni with and without Nb and Zr additions. Oxide scales were preformed in S-free environments and subsequently exposed to oxygen-sulfur mixed-gas atmospheres. Preformed scales were found to delay the onset of breakaway corrosion. The beneficial effects of refractory metal additions were achieved via formation of a barrier layer at the Cr2O3 alloy interface.
Why Students Withdraw from Classes

Abstract Professors (N = 30) and students (N = 151) rated the importance of possible reasons for withdrawing from classes. Analysis of their responses to a 15-item questionnaire revealed a significant difference between students and faculty (p < .05) on 9 of 14 items (64%). A factor analysis identified two reasons why students withdrew from classes: personal considerations and course considerations. Professors indicated that students' personal reasons for course withdrawal were more important than students indicated them to be. The difference in these results suggests that more feedback should be provided to professors about why students withdraw from courses.
Insight into catalytically relevant correlated motions in human purine nucleoside phosphorylase.

The catalytic site of the homotrimeric enzyme human purine nucleoside phosphorylase enzyme (hPNP) features residue F200 and the 241-265 loop directly skirting the purine base and a residue belonging to the adjacent monomer, F159, immediately conterminous to the ribosyl moiety. Crystallographic B-factors of apo human purine nucleoside phosphorylase, and hPNP complexed with substrate/transition state (TS) analogues, show that residue E250 is the centroid of a highly mobile loop region. Furthermore, superimposition of apo hPNP and hPNP complexed with TS analogue Immucillin-H shows a tightening of the active site, caused by the ligand-dependent 241-265 loop rearrangement taking place upon substrate/inhibitor binding, suggesting a putative dynamic role of the loop in binding/catalysis. However, crystallographic structures reveal only average atomic positions, and more detailed information is needed to discern the dynamic behavior of hPNP. The Essential Dynamics (ED) method is used here to investigate the existence of correlated motions in hPNP and consequently proposes mutagenesis assays to estimate the relative importance of these motions in the phosphorolytic efficiency of the reaction catalyzed by hPNP. We compare the concerted motions obtained from multiple molecular dynamics simulations of apo and Michaelis complex of hPNP both in vacuo and in solution. The results of the principal component analysis for the apo hPNP indicate the existence of strong correlations predominantly in the vicinity of residue F159. However, for the Michaelis complex, concerted motions are seen mostly around both active site residue F200 and loop residue E250. Additionally, for a simulation depicting the relaxation of tight complexed hPNP with a TS analogue, toward its relaxed apo form (after removal of the TS analog), a combination of the apo hPNP and Michaelis complex motions is found, with prominent concerted modes centered around neighboring residues F159, F200, and E250. Finally, we probed the extent to which these concerted motions bear an intrinsic catalytic role by performing experimental site-directed mutagenesis on some residues, followed by kinetic analysis. The F159G and F200G mutants displayed a strong increase in K M and modest decrease in k cat , suggesting that these concerted motions may provide dynamical roles in substrate binding and/or catalysis. However, further structural data for the hPNP mutants are needed to confirm our hypothesis.
Seminal Plasma Accelerates Semen-derived Enhancer of Viral Infection (SEVI) Fibril Formation by the Prostatic Acid Phosphatase (PAP248–286) Peptide *

Amyloid fibrils contained in semen, known as SEVI, or semen-derived enhancer of viral infection, have been shown to increase the infectivity of HIV dramatically. However, previous work with these fibrils has suggested that extensive time and nonphysiologic levels of agitation are necessary to induce amyloid formation from the precursor peptide (a proteolytic cleavage product of prostatic acid phosphatase, PAP248–286). Here, we show that fibril formation by PAP248–286 is accelerated dramatically in the presence of seminal plasma (SP) and that agitation is not required for fibrillization in this setting. Analysis of the effects of specific SP components on fibril formation by PAP248–286 revealed that this effect is primarily due to the anionic buffer components of SP (notably inorganic phosphate and sodium bicarbonate). Divalent cations present in SP had little effect on the kinetics of fibril formation, but physiologic levels of Zn2+ strongly protected SEVI fibrils from degradation by seminal proteases. Taken together, these data suggest that in the in vivo environment, PAP248–286 is likely to form fibrils efficiently, thus providing an explanation for the presence of SEVI in human semen.
Bone reaction in experimental periodontitis induced by delayed hypersensitivity.

Recent observations suggest that cellular immunity may play a role in periodontal disease.1-3 This conclusion is the result of the following: 1. Delayed hypersensitivity reactions to Actinomyces have been elicited in periodontal patients.4 2. Lymphocytes from individuals with periodontal disease show blastogenic response upon stimulation with plaque antigens,5-10 indicating previous antigen sensitization.11 In addition the supernatants from the stimulated cultures contain lymphokines, including macrophage inhibition factor, lymphotoxin, and monocyte chemotactic factor,12-14 which mediate the changes seen in delayed hypersensitivity.10-16 3. The early gingival response to plaque 17,18 includes many histologie features similar to (but not pathognomonic of) delayed hypersensitivity.19'20 4. Classical delayed hypersensitivity induced in the gingiva has many similar features with chronic gingivitis.21-22 While cell-mediated immunity may be protective during many bacterial infections, it also may participate in the progressive destruction of surrounding normal tissue.23, 24 The current studies were undertaken to examine whether delayed hypersensitivity induced in proximity to the alveolar bone may result in bone destruction.
Pinch-off modes and satellite formation in liquid/liquid jet systems

Abstract Forced jets of glycerin/water solution flowing into silicone oil were investigated. Forcing amplitudes were sufficient to induce stable or semi-stable pinch-off modes in the jet. The indices of refraction in the two liquids were matched, and planar slices of flow were visualized using laser induced fluorescence. Two-dimensional velocity fields were obtained by particle image velocimetry (PIV). For a viscosity ratio, η i / η o =1.6, satellites form at lower Reynolds numbers as well as lower Strouhal numbers. Satellite occurrence depends on the interface shape approaching pinch-off as well as the detailed velocity gradients surrounding the pinch-off region. Satellite formation required a zone of concave curvature downstream of but close to the jet neck as pinch-off approached. This zone was associated with intense vorticity that first deformed the interface into an upstream-facing cone attached to the main drop and then deformed the cone into a satellite shape. Increasing the ambient viscosity suppressed satellite formation for the Reynolds and Strouhal numbers examined.
T effectors outfox T regulators in autoimmunity.

Findings from a mouse model of multiple sclerosis suggest that regulatory T cells alone cannot outduel pathogenic T cells in the central nervous system. The observations may have implications for experimental approaches designed to dampen autoimmune diseases by infusion of regulatory T cells (pages 423–431).
Variables Associated with Export Profitability

This study is an analysis of variables associated with the profitability of exporting. Such information is useful both for export management and for government agencies that wish to promote business commitment to exporting. The methodology utilizes a multiple regression analysis of data in questionnaire responses from 168 Wisconsin manufacturing firms in 1979. It provides a means for evaluating difficult-to-measure export marketing considerations (such as, export marketing channels, export methods, and foreign dealer support) from the supply-side of the demand-supply equation which can be conceptualized as export marketing analysis from the supply-side.
Pure-tone sensitivity of 2- to 5-week-old infants

Abstract The behavioral response of 2- to 5-week-old infants to pure tones was examined. In the first experiment, tones at 500, 1000, and 4000 Hz at levels ranging from 25 tO 70 dB SPL were delivered to infants through a probe tube inserted in the ear canal. A trial consisted of five repetitions of a 500-ms tone burst at a fixed level, followed by 5 s of silence, and either five more repetitions of the same tone burst (signal trial), or 5 more s of silence (no-signal trial). An observer, blind to trial type, judged whether a signal or no-signal trial had occurred on the basis of the infant's behavior. The observer also provided a confidence rating for the judgment on each trial. The results showed that at 500 and 4000 Hz, the observer's performance improved as the level of the tone increased. Psychometric functions were fit to the data at these frequencies, combined over infants. The group thresholds calculated from these functions suggested similar sensitivity at 500 and 4000 Hz. There were some infants who contributed enough trials to establish an individual psychometric function. The average individual 4000-Hz threshold for these infants was lower than the estimate obtained from the group function, but sensitivity was still about the same at all three frequencies, relative to adults. Analysis of receiver operating characteristic curves generated from the confidence ratings, however, suggested that young infants are less sensitive to 4000-Hz than to 500-Hz tones when response bias is controlled. Finally, the results of a second experiment, in which the same procedure was used to examine the response of infants to 1000-Hz tone bursts at levels between 5 and 35 dB SPL, suggested that the infant threshold at this frequency is around 25 dB SPL. In the context at the first experiment, this further suggests that the range of sound intensities presented can dramatically influence the responses of infants to sound.
Vasopressin Release Due to Manual Restraint in the Rat: Role of Body Compression and Comparison with Other Stressful Stimuli*

ABSTRACT. The observation of plasma vasopressin elevations in rats which had been held manually for 1–2 min before decapitation prompted a study of this and other stressful stimuli. Plasma vasopressin concentrations determined by RIA [picograms per ml (±SEM)] were: 1) immediate decapitation after removal from cage, 1.69 ± 0.28; 2) manual restraint for 3 min, 42.4 ± 12.3; 3) light ether anesthesia, 1.97 ± 0.32; 4) forced exercise in the activity wheel (3 min), 2.09 ± 0.28; 5) swimming (3 min), 2.2 ± 0.44; 6) noise by continuous hammering on cages (3 min), 1.64 ± 0.37; 7) electric shock in plastic restrainers, 93 ± 35; 8) restraint in plastic restrainers without electric shock (control for group 7), 1.87 ± 0.43; and 9) body compression by firm squeeze around the trunk (1 min), 283 ± 111 (range, 30–1200 pg/ml). Aside from electric shock, which could well have caused direct excitation of neurohypophysis, no stressful stimulus produced vasopressin elevations except the light squeeze of manual restraint and the...
A modified stationary principle for nonlinear waves

Abstract Two theorems related to propagation of modulated, nonlinear waves which are governed by stationarity of the integral of a Lagrangian density are derived. They are then used in the analysis of asymptotic approximations which represent nearly uniform wave trains. A relatively detailed treatment of a simple case is followed by a summary of some results which apply to the propagation of capillary-gravity waves in a liquid.
Introduction to the Special Issue on transformative consumer research: Developing theory to mobilize efforts that improve consumer and societal well-being

Abstract The third biennial Transformative Consumer Research Conference at Baylor University in June 2011 encouraged consumer researchers from around the world to address some of the world's most pressing social and economic problems. Researchers discussed with conceptual rigor nine substantive areas: addiction; food for thought; innovative research methods; materialism; youth, risk and consumption; multicultural marketplaces; poverty and subsistence marketplaces; sustainable products; and transformative services research. This introductory paper summarizes the contributions of the post-conference articles on these nine areas that appear in this special issue, and it highlights the importance of conducting consumer research to obtain theoretically-grounded findings that offer practical solutions to serious human problems.
Identification of a Novel Isoform of Microsomal Triglyceride Transfer Protein

Microsomal triglyceride transfer protein (MTP) has been studied extensively, primarily because of its role in the assembly of very low density lipoproteins by the liver and chylomicrons by the intestine. Recent studies have suggested that MTP may also play key roles in other cellular processes. In this paper we report the identification of a novel splice variant of MTP in mice. This isoform, MTP-B, has a unique first exon located ∼2.7 kilobases upstream of canonical MTP (MTP-A) exon 1. The alternative exon encodes 35 amino acids compared with 20 amino acids encoded by exon 1 of MTP-A. MTP-B represents ∼90% of total MTP mRNA in mouse adipocytes and 3T3-L1 cells and
A comparison of PIV measurements of canopy turbulence performed in the field and in a wind tunnel model

Particle image velocimetry (PIV) has been used to compare between turbulence characteristics just within and above a mature corn canopy and those of a model canopy setup in a wind tunnel (WT). The laboratory normalized mean velocity profile is adjusted using variable mesh screens to match the normalized mean shear of the corn field (CF) data. The smallest resolved scale in the field is about 15 times the Kolmogorov length scale (ηCF ≈ 0.4 mm), whereas in the WT it is 5 times ηWT (ηWT ≈ 0.15 mm). In both cases, the mean velocity and turbulence statistics are consistent with those measured using single point sensors. However, the profiles of normalized Reynolds shear stress in the field and the laboratory differ. Turbulent spectral densities calculated from PIV spatial and time series in the field display an inertial range spanning three decades. In the laboratory due to lower Reynolds numbers, the inertial range shrinks to two decades. Quadrant-Hole analysis is applied to Reynolds shear stress, vorticity magnitude and dissipation rates. In quadrants 1–3, the WT and field conditionally sampled stresses show similar trends. However, a conflicting trend is found in the sweep quadrant. The analysis confirms that sweep and ejections dominate the momentum flux and dissipation rate.