cssi/SciSciGPT-SciSciNet huggingface dataset:
Carrier trapping and recombination in avalanche diodes

The differential equations describing an avalanching p+nn+junction in the presence of multiple-level carrier traps have been solved numerically for trap densities as high as two orders of magnitude greater than the n-region background doping. The results compare quantitatively with a number of past, as well as new, experimentally observed changes in avalanche microwave diode performance with neutron damage. In particular, trapped charge in the space-charge region tends to localize the avalanche region near the p+n junction, which raises the frequencies of operation. Carrier trapping at the edges of the space-charge region explains the increase in operating voltage and decrease in small-signal capacitance. The localization of the avalanche region, through carrier trapping in the space-charge region, and recombination effects at high avalanche current densities combine to cause eventual RF failure of IMPATT and TRAPATT diodes with neutron damage.
Upregulation of caveolin-1 and caveolae organelles in Taxol-resistant A549 cells

Caveolin is a principal component of caveolae membranes. It has been demonstrated that the interaction of the caveolin scaffolding domain with signaling molecules can functionally inhibit the activity of these molecules. Taxol is an antitumor agent that suppresses microtubule dynamics and binds to microtubules thereby stabilizing them against depolymerization. The drug also has been implicated in the induction of apoptosis through activation of components in signal transduction cascades. Here we have investigated the role of caveolin in the development of drug resistance by examining the expression of caveolins in low- and high-level drug-resistant cell lines. Caveolin-1, but not caveolin-2, was upregulated in highly multidrug resistant SKVLB1 cells that express high levels of P-glycoprotein, and in low-level Taxol-resistant A549 cell lines that express low amounts of P-glycoprotein. Two drug-resistant A549 cell lines (one 9-fold resistant to Taxol and the other 1.5-fold resistant to epothilone B), both of which express no P-glycoprotein, demonstrate a significant increase in the expression of caveolin-1. These results indicate that in low-level epothilone B- or Taxol-resistant A549 cells, increased caveolin-1 expression occurs independently of P-glycoprotein expression. Electron microscopic studies clearly demonstrate the upregulation of caveolae organelles in Taxol-resistant A549 cells. Upregulation of caveolin-1 expression in drug-sensitive A549 cells was observed acutely beginning 48 h after incubation with 10 nM Taxol. Thus, caveolin-1 may play a role in the development of Taxol resistance in A549 cells.
Effects of serum versus plasma on agglutination of antibody-coated indicator cells by human rheumatoid factors.

Abstract Plasma and serum contain an inhibitor (1) of the agglutination of rabbit IgG-coated sheep erythrocytes by human rheumatoid factor (RF). Plasma but not serum contains an inhibitor of the inhibitor ( I I ) which allows RF to interact with its target. In normal blood, there is more I than I I , and I can be removed by solid-phase chromatography through concanavalin A (Con A). Plasma I I is heat labile being eliminated by heating at 56°C for 30 min. Addition of exogenous calcium clots EDTA plasma, causing an irreversible loss of I I , and suggesting its involvement in the clotting cascade. The absence of I I from Factor V-deficient plasma and destruction of I I by Russell's viper venom indicate I I either is associated with or is a part of Factor V. These findings suggest a balanced interplay between I and I I , and indicate results of immunological tests done in vitro may not accurately reflect immune function in vivo. This seems to represent an unexplored link between hemostasis and immunity.
Acyclic identification of aptamers for human alpha-thrombin using over-represented libraries and deep sequencing

Background Aptamers are oligonucleotides that bind proteins and other targets with high affinity and selectivity. Twenty years ago elements of natural selection were adapted to in vitro selection in order to distinguish aptamers among randomized sequence libraries. The primary bottleneck in traditional aptamer discovery is multiple cycles of in vitro evolution. Methodology/Principal Findings We show that over-representation of sequences in aptamer libraries and deep sequencing enables acyclic identification of aptamers. We demonstrated this by isolating a known family of aptamers for human α-thrombin. Aptamers were found within a library containing an average of 56,000 copies of each possible randomized 15mer segment. The high affinity sequences were counted many times above the background in 2–6 million reads. Clustering analysis of sequences with more than 10 counts distinguished two sequence motifs with candidates at high abundance. Motif I contained the previously observed consensus 15mer, Thb1 (46,000 counts), and related variants with mostly G/T substitutions; secondary analysis showed that affinity for thrombin correlated with abundance (Kd = 12 nM for Thb1). The signal-to-noise ratio for this experiment was roughly 10,000∶1 for Thb1. Motif II was unrelated to Thb1 with the leading candidate (29,000 counts) being a novel aptamer against hexose sugars in the storage and elution buffers for Concanavilin A (Kd = 0.5 µM for α-methyl-mannoside); ConA was used to immobilize α-thrombin. Conclusions/Significance Over-representation together with deep sequencing can dramatically shorten the discovery process, distinguish aptamers having a wide range of affinity for the target, allow an exhaustive search of the sequence space within a simplified library, reduce the quantity of the target required, eliminate cycling artifacts, and should allow multiplexing of sequencing experiments and targets.
From hexamer to amyloid: Marginal stability of apolipoprotein SAA2.2 leads to in vitro fibril formation at physiological temperature

Serum amyloid A (SAA) is a major acute phase reactant and a small apolipoprotein of high density lipoproteins (HDL) in the serum. In cases of prolonged inflammation, SAA may form amyloid fibrils, leading to the disease of amyloid A (AA) amyloidosis. Recently, we have shown that murine SAA2.2, a non-amyloidogenic isoform in vivo, forms a hexamer in vitro containing a putative central channel. It is reported herein that upon thermal denaturation, hexameric SAA2.2 irreversibly dissociates to a misfolded monomer at physiological temperature, formation of which coincides with a significant loss of alpha-helical and gain of beta-sheet structure. When SAA2.2 is incubated for several days at 37 degrees C, sedimentation analytical ultracentrifugation reveals the presence of soluble high molecular weight aggregates, which upon further incubation undergo subsequent self-assembly into amyloid fibrils. Limited proteolysis experiments suggest that the in vitro amyloidogenecity of SAA2.2 is related to structural alteration in its N-terminus. Our observation that SAA2.2 can form amyloid fibrils in vitro at physiological temperatures suggests that SAA2.2's inability to cause amyloidosis may be related to other factors, such as the stabilization of hexameric SAA2.2 (possibly through ligand binding), and/or the slow kinetics of aberrant misfolding and self-assembly.
Capitalization, population movement, and the local public sector: a probabilistic analysis.

Abstract A probabilistic model is used to relate population movement to the capitalization of the local public sector into the price of housing. This explanation is used to analyze the predicted effects of differing public policies on the composition of San Francisco's population. The model is also used to test the relative merits of the two explanations of the flight of higher-income households from the central city: the Accessibility and Flight from Blight models. The findings suggest that neither model can completely explain this flight exclusive of the other.
Aircraft System Safety: Military and Civil Aeronautical Applications

Aircraft System Safety: Military and Civil Aeronautical Applications, by Duane Kritzinger, CRC Press, Boca Raton, Florida, USA, 2006, pp. 350, £117.00, hardback (ISBN 0 8493 9012 5). Also published...
Adsorption of xenon and krypton on shales

A method that uses a mass spectrometer as a manometer is employed in the measurement of Xe and Kr adsorption parameters on shales and related samples, where gas partial pressures were lower than 10 to the -11th atm, corresponding adsorption coverages are only small fractions of a monolayer, and Henry's Law behavior is expected and observed. Results show heats of adsorption in the 2-7 kcal/mol range, and Henry constants at 0-25 C of 1 cu cm STP/g per atmosphere are extrapolated. Although the adsorption properties obtained are variable by sample, the range obtained suggests that shales may be capable of an equilibrium adsorption with modern air high enough to account for a significant fraction of the atmospheric inventory of Xe, and perhaps even of Kr. This effect will nevertheless not account for the factor-of-25 defficiency of atmospheric Xe, in comparison with the planetary gas patterns observed in meteorites.
Symbolic representation of hyperspectral data

We have developed a symbolic representation of hyperspectral data using the scale space techniques of Witkin. We created a scale space image of hyperspectral data from convolution with Gaussian masks and then a fingerprint that extracts individual features from the original data. The fingerprint provides a context that pairs inflection points and assigns them to a feature, generates a measure of importance for each feature, and relates features to each other. The representation is an ordered sequence of triplets containing a measure of importance related to the area of each feature and the left and right inflection points of the feature. The description is compact, quantitative, and hierarchical, describing the hyperspectral curve by its most important structural features first, followed by features of lesser importance.
Specific binding of 125I-LHRH agonist to hippocampal membranes: fluctuations during the estrous cycle.

Abstract Specific binding of 125I-[D-Ala6-CH3-Leu7-Pro9,NHET]LHRH, a LHRH agonist, to hippocampal membranes prepared from ovariectomized female rates was examined. One high affinity binding site was observed with a K d of 0.12 ± 0.01 n M and an apparent B max of 13.0 ± 3.8 fmol/mg . Luteinizing hormone-releasing hormone and the behaviorally active Ac-LHRH(5–10) were able to compete for the agonist binding site. Native LHRH had an apparent K i of 1.73 n M , while AC-LHRH(5–10) was 30 times less potent. Competition studies examined over the rat estrous cycle revealed an eighteenfold decrease in apparent affinity during diestrus I and estrus compared with ovariectomized animals. Tissue from animals in proestrus had a K i of 5.0 n M . Specific binding studies indicate that receptor concentration is highest in proestrus ( 6.11 ± 0.90 fmol/mg ) and significantly lower during estrus ( 2.4 ± 0.29 fmol/mg ). These data suggest that at least one fragment of native LHRH can interact with neuronal LHRH receptors and that these receptors, like those in the pituitary, can be modulated by circulating steroid hormones.
High-temperature superconductivity in the presence of O 2p--Cu 3d holes: A spectroscopic study

We report core-level spectroscopic measurements of several cuprate perovskites comparing those which exhibit superconductivity above 90 K to others which do not. Both x-ray photoemission and x-ray absorption results show that in the former Cu is more oxidized, as in CuO (nominally ${\mathrm{Cu}}^{2+}$), than in the latter. Trivalent Cu is clearly excluded. The O $1s$ core level is at higher binding energy in the superconductors, implying the presence of O $2p$ holes. The rare-earth valence in Ce- and Pr-based perovskites is more than 3+, apparently related to their failure to superconduct.
Security and Crime in Health Sciences Libraries in the Southern United States

Crime is a part of life that has become more evident in libraries through reports in journals, newspapers, television, and other media. As the result of a sharing session, a survey was conducted of the libraries composing the South Central Chapter of the Medical Library Association. This survey looked at the incidence of major and minor crimes in the libraries and their institutions; security measures, regulations, or policies that were in effect prior to these or having been initiated since; and the effect the crimes and/or security measures have had on the institution and its employees.
Resonant low energy electrons and their impact on sampling depth during backscatter-electron ms̈sbauer spectroscopy

Collection of low energy electrons (< 15 eV) during Conversion Electron Mossbauer Spectroscopy (CEMS) provides enhanced surface sensitivity. To identify and quantify the potential surface sensitivity provided by these species, spectra were collected from a 92.8% enriched 57Fe foil using retarding field energy analyzers in conjunction with spiraltron electron multipliers. Both resonant and nonresonant count rates decrease by as much as 50% at 10 eV bias potential establishing that a large fraction of low energy electrons is produced during CEMS. Surface enhancement due to low energy electrons was identified by observing inherent signal-to-background ratios from samples with the topmost 1.0 nm chemically labeled. The area ratio of the 1.0 nm overlayer to the substrate was 1.43 at 0 eV bias potential while at 15 eV bias potential the area ratio decreased to 0.72. By vacuum evaporating a 5.0 nm copper coating on the sample, near complete attenuation of the excess low energy electrons from the 1.0 nm overlayer was achieved. These results suggest that some low energy electrons below 15 eV are formed as primary products of electronic relaxation following nuclear decay and that they are not the result of straggling or other scattering phenomena. Low energy resonant electron signals appear useful for surface science applications by permitting information from the topmost monolayers to be readily distinguished from those signals arising from deeper within the solid.
Endothelial cells regulate cardiac contractility.

Abstract Endothelial cells lining the lumen of blood vessels contain the receptors for many substances that alter the contractile tone of smooth muscle in the walls of the blood vessels. In response to their interaction with the signal substances, the endothelial cells release vasoactive factors that modify the contractile state of the vascular smooth muscle. This study was conducted to determine if endothelial cells can also modulate the contraction of cardiac muscle cells and contribute to the physiological regulation of the heart. The venous effluent from the coronary circulation of an isolated perfused working heart was reoxygenated and used to superfuse a trabecula isolated from the right ventricle of another heart. The peak tension and the duration of the contraction of the trabecula were reversibly altered by the effluent fluid. The change in the contraction of the trabecula during its exposure to coronary effluent was inhibited by selectively damaging the endothelial cells in the trabecula before the application of the coronary effluent. The magnitude and direction of the effect of the coronary venous effluent were sensitive to the metabolic and mechanical conditions under which the isolated perfused heart was contracting at the time the effluent was collected. These observations indicate that cardiac tissue can release a substance or substances into the coronary circulation that induce the production of cardioactive factors by endothelial cells.
CONSERVATIVES, LIBERALS, RADICALS, AND SENSATION-SEEKERS

In today's increasingly polluted and politicized atmosphere, one is often pressured, either forcibly or subtly, to identify his personal location, either publicly or privately, on a conservative-liberal political continuum (with radical extensions on either end). Some persons, particularly those toward the ends of this continuum, exhibit a strong need to proclaim their identificacjon with great fervor and display, while those in the middle are understandably less ardent about the whole business. This pilot work was done to check the "sensation-seeking" correlates, or the need for stimulus variation or novelty, of these political identifications. A total of 119 university students (40 men, 79 women; mostly juniors and seniors) were asked to locate themselves on a five-point conservative-liberal political continuum (with extensions for radicalism on both ends). In addition, each person filled our three questionnaires which purport to measure the need for sensation-seeking or stimulus change (sample item: "An element of risk adds to my enjoyment of an activity or event.") : The Change Seeker Index (CSI; 1), the Stimulus-variation Seeking Scale (SVSS; 2), and the sensation-seeking Scale (SSS; 3). The political ideology self-racings were scored on a five-point scale, with 1 assigned to radicals at the conservative end and 5 assigned to radicals at the opposite end. The Pearsonian correlations among these self-ratings and the various measures of sensation-seeking were: SVSS. .17; SSS, .38; CSI, .41. There was a negative but nonsignificant r of -.14, with birth order, and males tended to be slightly more "leftish than females (mean self-rating for males, 3.55; females, 3.10). The over-all mean political ideology rating for this group of university students was 3.24 (SD = 1.05). These data suggest that persons who identify toward the liberal-left of the political continuum may be desirous of an environment filled with novelty and change (as measured by the SSS or the CSI). REFERENCES
Encapsulation of ionic polymer-metal composite (IPMC) sensors with thick parylene: Fabrication process and characterization results

Abstract Ionic polymer-metal composites (IPMCs) tend to have inconsistent sensing properties when operating in air under different humidity levels, or after exposure to different ambient media. Motivated by the need to ensure consistent sensing performance of IPMCs under different ambient environments, in this paper we propose thick (up to 25 micrometers) parylene C coating for IPMC sensors, develop effective coating processes, and evaluate the performance of the encapsulated sensors, along with the comparison with the typical naked IPMC sensors. The proposed fabrication process features the water drive-in step which enables the control and adjustment of the hydration level of an encapsulated IPMC. Experiments are conducted to evaluate the sensing consistency of IPMC sensors in a humidity chamber, first under different humidity levels, and then following exposure to solutions with different cations and different organic solvents. Experimental results show that the proposed thick parylene coating can effectively keep the water content inside the IPMC, isolate the IPMC sensor from various ambient environments, and maintain the sensing consistency, which allows IPMC sensors to be used in practical applications.
Geometric phase effects in chemical reaction dynamics and molecular spectra

The theoretical methodology for including the effects of the geometric phase in quantum reactive scattering and bound-state calculations is reviewed. Two approaches are discussed: one approach is based on solving the standard Born−Oppenheimer equation but with double-valued boundary conditions, and the second approach is based on solving a generalized Born−Oppenheimer equation with single-valued boundary conditions. The generalized Born−Oppenheimer equation contains a vector potential which is mathematically equivalent to that of a magnetic solenoid. The recently developed numerical methodology for solving the generalized Born−Oppenheimer equation is reviewed, and several applications of this methodology in chemical reaction dynamics and molecular spectra are discussed. New results from accurate six dimensional quantum reactive scattering calculations for the D + H2(v, j) → HD(v‘, j‘) + H and H + H2(v, j) → H2(v‘, j‘) + H reactions are presented. These calculations are performed both with and without the...
Electrical conductivity of random silver-potassium chloride composites

The complex alternating current (a.c.) impedance of random silver-potassium chloride (Ag-KCl) composite specimens near the percolation threshold has been measured in the frequency range 5 Hz to 13 MHz. The impedance of these composites as a function of metal volume fraction and direct current (d.c.) potential field are presented. This a.c. response, which is correlated with structural and compositional characterization of these composites, is used to examine the applicability of several different theoretical models as well as to determine the important factors in the electrical conductivity of such materials.
Far‐Red Fluorogenic Probes for Esterase and Lipase Detection

Fluorogenic enzyme probes go from a dark to a bright state following hydrolysis and can provide a sensitive, real-time readout of enzyme activity. They are useful for examining enzymatic activity in bacteria, including the human pathogen Mycobacterium tuberculosis. Herein, we describe two fluorogenic esterase probes derived from the far-red fluorophore 7-hydroxy-9H-(1,3-dichloro-9,9-dimethylacridin-2-one) (DDAO). These probes offer enhanced optical properties compared to existing esterase probes because the hydrolysis product, DDAO, excites above 600 nm while retaining a good quantum yield (ϕ=0.40). We validated both probes with a panel of commercially available enzymes alongside known resorufin- and fluorescein-derived esterase substrates. Furthermore, we used these probes to reveal esterase activity in protein gel-resolved mycobacterial lysates. These probes represent new tools for esterase detection and characterization and should find use in a variety of applications.
Ia-bearing cells promote the concanavalin a mitogenic response of ia-negative t cells.

Nylon wool column-purified T cell populations depleted of Ia-bearing cells do not respond to the T cell mitogen concanavalin A (Con A). The response of this population can be restored by admixture of untreated nylon wool-nonadherent T cells. These promotor cells express Thy-1, are not sensitive to mitomycin C treatment and cannot be replaced with adherent spleen cells. Experiments using the T6 chromosome marker demonstrate that Ia-depleted populations respond to ConA only in the presence of the Ia-positive population.
Greater Sage-Grouse Nesting Habitat: The Importance of Managing at Multiple Scales

Abstract Considering habitat selection at multiple scales is essential to fully understand habitat requirements and management needs for wildlife species of concern. We used a hierarchical information-theoretic approach and variance decomposition techniques to analyze habitat selection using local-scale habitat variables measured in the field and landscape-scale variables derived with a Geographic Information System (GIS) for nesting greater sage-grouse (Centrocercus urophasianus) in the Powder River Basin (PRB), Montana and Wyoming, USA, 2003–2007. We investigated relationships between habitat features that can and cannot be mapped in a GIS to provide insights into interpretation of landscape-scale–only GIS models. We produced models of habitat selection at both local and landscape scales and across scales, yet multiscale models had overwhelming statistical and biological support. Variance decomposition showed that local-scale measures explained the most pure variation (50%) in sage-grouse nesting-habita...
The neuroendocrine regulation of Drosophila aging

The rate of aging is regulated by hormones in insects and, most likely, in mammals. Mutations of the insulin-signaling pathway extend lifespan in the fruit fly and influence the level of other hormones, specifically juvenile hormone and the sterol ecdysone, each of which may directly influence senescence. With new genetic and genomic tools in Drosophila biology we are now exploring how the neuroendocrine system responds to environmental conditions to modify insulin action, how these signals control secondary hormones, and how these messages together modulate animal aging.
Analysis and reporting of platelet kinetic studies

BACKGROUND: For platelet (PLT) kinetic studies in the healthy subject, autologous transfusion models are standardly used for the evaluation of new or modified PLT collection or treatment methods. The investigator is usually seeking to demonstrate that the new product is not inferior to a control condition. Consistent, statistically sound analysis and reporting methods will enable clear interpretation and communication of the results. STUDY DESIGN AND METHODS: Noninferiority hypotheses are constructed in light of a recent FDA workshop. One- and two-stage analysis methods are described to evaluate the paired differences in control and test arms with calculation of upper confidence intervals. Sample size estimates are presented for various experimental design options. The sensitivity of sample size to the difference in test and control recoveries is performed. RESULTS: The noninferiority hypothesis test was applied to a recently published study. Seven-day, plasma-stored apheresis PLTs were shown to be noninferior to freshly prepared PLTs with 95 percent confidence that the difference in recovery was not more than 11.4 percent and survival not more than 2.6 days, with maximum acceptable differences of 19.8 percent and 4.4 days. As the test recovery and survival approach the minimum acceptable value, the sample size required to demonstrate noninferiority increases nonlinearly. Preliminary sample size calculations presented here suggest that for most studies such as this, a minimum sample size of 7 should be anticipated. Because most of these studies are used to support regulatory submissions, this is usually executed in at least two centers for a total minimum of 14. CONCLUSION: The randomized, paired design is the most efficient approach to these studies. Consistent reporting of summary statistics for each test arm and the paired differences, the upper confidence limit for the differences in recovery and survival, and the maximum acceptable difference for each is recommended.
Initiation and characterization of a diploid cell line from larval tissues of Aedes dorsalis (Meigen).

Mosquito cell cultures were initiated from the minced tissues of newly hatchedAedes dorsalis (Meigen) larvae. Continuous cell division occurred only after an adaptive period of approximately 6 months. Optimal growth of the cells required a relatively low pH of 6.5. Karyological studies showed that the cells have remained diploid (2n=6) for 60 serial passages and that the cultures are free of contaminating cells. The cultures also were shown to be free of bacteria (includingMycoplasma), fungi and virions. Subpopulations (strains) of the original parental cultures have been selected and characterized on the basis of morphology, karyology, growth rate and monolayer formation.
Confessions of a Bedside Rationer: Commentary on Hurst and Danis

Samia Hurst and Marion Danis provide a thoughtful framework for how to judge the morality of bedside rationing decisions. In this commentary, I applaud Hurst and Danis for advancing the level of debate about bedside rationing. But when I attempt to apply the framework to my own clinical practice, I conclude that the framework comes up short.
Striped phases in two-dimensional dipole systems

We prove that a system of discrete two-dimensional (2D) in-plane dipoles with four possible orientations, interacting via a three-dimensional (3D) dipole-dipole interaction plus a nearest neighbor ferromagnetic term, has periodic striped ground states. As the strength of the ferromagnetic term is increased, the size of the stripes in the ground state increases, becoming infinite, i.e., giving a ferromagnetic ground state, when the ferromagnetic interaction exceeds a certain critical value. We also give a rigorous proof of the reorientation transition in the ground state of a 2D system of discrete dipoles with six possible orientations, interacting via a 3D dipole-dipole interaction plus a nearest neighbor antiferromagnetic term. As the strength of the antiferromagnetic term is increased, the ground state flips from being striped and in plane to being staggered and out of plane. An example of a rotator model with a sinusoidal ground state is also discussed.
High Frequency Retrotransposition in Cultured Mammalian Cells

We previously isolated two human L1 elements (L1.2 and LRE2) as the progenitors of disease-producing insertions. Here, we show these elements can actively retrotranspose in cultured mammalian cells. When stably expressed from an episome in HeLa cells, both elements retrotransposed into a variety of chromosomal locations at a high frequency. The retrotransposed products resembled endogenous L1 insertions, since they were variably 5' truncated, ended in poly(A) tracts, and were flanked by target-site duplications or short deletions. Point mutations in conserved domains of the L1.2-encoded proteins reduced retrotransposition by 100- to 1000-fold. Remarkably, L1.2 also retrotransposed in a mouse cell line, suggesting a potential role for L1-based vectors in random insertional mutagenesis.
Acting as Fire Alarms With Law Enforcement?: Interest Groups and Bureaucratic Activity on Hate Crime

In this article, I present an exchange theory of interest group activity that specifies the incentives and constraints on interest group activity to explain the degree to which some interest groups try to influence bureaucratic activity on hate crime, the types of tactics groups use, and to assess their influence on police procedures. I test several related propositions from this theory using original survey and demographic data from a sample of anti-violence groups in the 250 largest American cities. The results of my analysis suggest that interest group attempts to influence bureaucratic action on hate crime are constrained by the group characteristics, their sources and use of financial resources, and the characteristics of the communities in which they operate.
Is there a winner's curse in the labor market?

Abstract When a firm can make counteroffers to workers who have received outside wage offers, a winner's curse effect may exist. Raided firms do not make counteroffers to those whose value is less than the raider's wage offer, so the raider always earns negative profit when a raid is successful. In this paper, I demonstrate that, when a raided firm makes reassignment decisions in anticipation of outside wage offers, and there is at least an infinitesimal probability of exogenous turnover, a winner's curse will not occur when there are counteroffers, except possibly for workers at the lowest task assignment.
Crystal structure of potassium neodymium metaphosphate, KNdP4O12, a new acentric laser material☆

Abstract A new high-Nd-concentration laser material, KNdP 4 O 12 , has been synthesized by a flux method. A single-crystal x-ray-diffraction analysis has characterized this structure as monoclinic with space group P2 1 , z = 2, and cell parameters a = 7.266(1) A , b = 8.436(1) A , c = 8.007(1) A , β = 91.97(1) o . A full-matrix least-squares refinement gave R = 0.060, Rw = 0.067 for all 724 independent reflections. Helical ribbons, (PO 3 ) n , running along the a-axis are formed by corner-sharing of PO 4 tetrahedra. These ribbons are connected by isolated NdO 8 dodecahedra, and K atoms occupy irregular interstitial polyhedra. The shortest Nd-Nd distance is 6.661 A, and the concentration of Nd atoms is 4.08 × 10 21 cm −3 . Concentration quenching is reduced by the isolation of the Nd polyhedra. The fluorescence lifetime of KNdP 4 O 12 is 100 μsec, that of KNd 0.01 Gd 0.99 P 4 O 12 is 275 μsec. The space group of KNdP 4 O 12 is acentric, which may allow nonlinear optical processes (e.g., second-harmonic generation) as well as linear electro-optic modulation to be carried out directly in the laser crystals.
Some kinetic aspects of sperm specific lactate dehydrogenase in mice.

Purified LDH-X, LDH-1, and LDH-5 isozymes from mouse tissues were compared according to several biochemical parameters. The sperm specific LDH-X is more thermostable than the other isozymes, retaining 100% activity after 30 minutes at 65°C. Activity of LDH-1 is reduced by 50% under these conditions while LDH-5 is completely inactivated at this temperature within 18 minutes. The three isozymes had different Km values for both pyruvate and lactate with LDH-X showing the highest substrate “affinities.” In addition, LDH-X reacted significantly with both α-hydroxy-valerate and ketovalerate substrates. There was little or no catalytic activity of LDH-X with other substrates, including several steroids, β-hydroxybutyrate, α-hydroxyisobutyrate, α-ketoglutarate, α-hydroxycaproate, and sorbitol.
Projective method applied to three‐dimensional elasticity equations

It is shown how the elasticity equations can be formulated in terms of a general procedure of abstract analysis, called the projective method, for constructing an approximate solution. This allows the many studies of convergence and uniqueness of solutions which have been made in modern mathematics to be applied to the elasticity problem. The abstract formulation also suggests an organizational scheme for generating a computer code. A computer code for hollow or solid cylinders of arbitrary cross section was developed and several numerical examples are presented. The procedure is computationally advantageous for the class of problems under consideration because of the relatively small number of equations that must be solved as compared to the finite element method. The results presented demonstrate the accuracy of the method.
Citrate production from hydrocarbons by use of a nonsterile, semicontinuous cell recycle system

In order to minimize product toxicity, decrease fermentation cost, prolong the effective production phase, and shorten the lag phase before production in the citrate-hydrocarbon fermentation by Candida lipolytica ATCC 8661, the use of a nonsterile semicontinuous cell recycle system was investigated. Model experiments demonstrated that portions of the fermentor broth could periodically be removed and centrifuged under nonaseptic conditions with the cells being added to fresh medium and returned to the fermentor. Citrate production continued, however with repeated semicontinuous cell recycle, acid production gradually decreased. It was postulated that this decrease could be attributed largely to physiological trauma and that a truly continuous cell recycle system would minimize these effects and permit maintenance of higher citrate production rates.
Stability and Change in Self-Perception and Achievement Among Black Adolescents: A Longitudinal Study

This study of self-perception and achievement among Black adolescents surveyed 248 thirteen- and fourteen-year-old eighth graders in 1980 who were previously surveyed as ten- and eleven-year-old fifth graders in 1977. The major devel opmental dimensions investigated were stability—whether or not these youngsters exhibited self-perception and/or achievement patterns of an erratic turmoil ridden or con tinuous nature, and chunge—the nature of the differences found in self-perception and achievement between the pre- adolescent and adolescent periods. Data are presented also on the White youngsters included in the survey. The objec tive of providing these data is to assess whether adolescent development occurs differently in Black and White Ameri can culture. Along this line the problematic tradition of generalizing to Black children, the patterns of cognition and performance found in White children, and some ideological problems of critical importance to an emerging "Black" psychology are discussed. The find...
Fourier transform Raman spectra of diamond‐like carbon films

Fourier transform (FT) Raman spectra (3500-50 cm −1 ) were recorded for hard diamond-like carbon (DLC) films deposited on silicon wafer substrates at various temperatures. The observed frequency of the graphitic optic zone center phonon (G) at 1595 cm −1 was found to remain constant with variations in the deposition temperature of the substrate, the excitation wavelength and the laser power. However, the disorder activated optical zone edge phonon (D), observed in the 1380-1250 cm −1 region, exhibits changes in the band maximum frequency with the abovementioned variable FT Raman spectroscopy, applied to these films, is shown to be a useful probe for the identification of various different types of diamond-like structures which are present
Septal lesions lower responding under fixed-ratio schedules of reinforcement.

Albino Sprague—Dawley rats with complete septal lesions and rats with control operations were studied under fixed-ratio (FR) schedules of reinforcement. Both groups were trained for 10 sessions each under FR 10, 20, 40, 60, 80, and 100. In contrast to findings from progressive FR studies and some simple FR studies, septal lesions resulted in lower overall and local response rates along with longer postreinforcement pauses. These effects were especially evident during the FR 100 schedule of reinforcement. A comparison of reinforcement rate as a function of FR size within the context of behavioral economics (i.e., a demand function) indicated that septal lesions did not alter the reward value of food. These findings suggest that responding on FR schedules of reinforcement can be altered by the various procedures used to train rats to reach the terminal value of a reinforcement schedule.
The effect of methylation upon the antioxidant and chelation capacity of quercetin and dihydroquercetin in a lard substrate

SUMMARY The relative importance of the hydroxyl group positions of quercetin and the metal-complexing sites of the molecule to antioxidant capacity in lard was investigated. The antioxidant action of quercetin seems to be a combination of reaction with free radicals and metal-ion complexing; with the former being the more important. Selective methylation of the hydroxyl groups of the quercetin molecule generally decreased the antioxidant activity. Ultraviolet absorption spectra of quercetin and copper-quercetin complexes suggest that quercetin will complex two moles of copper ion by intramolecular complexing and a third by intermolecular complexing. Copper-quercetin complexes retain some antioxidant ability although it is much less than that of uncomplexed quercetin.
Embedding Plasmonic Nanostructure Diodes Enhances Hot Electron Emission

When plasmonic nanostructures serve as the metallic counterpart of a metal–semiconductor Schottky interface, hot electrons due to plasmon decay are emitted across the Schottky barrier, generating measurable photocurrents in the semiconductor. When the plasmonic nanostructure is atop the semiconductor, only a small percentage of hot electrons are excited with a wavevector permitting transport across the Schottky barrier. Here we show that embedding plasmonic structures into the semiconductor substantially increases hot electron emission. Responsivities increase by 25× over planar diodes for embedding depths as small as 5 nm. The vertical Schottky barriers created by this geometry make the plasmon-induced hot electron process the dominant contributor to photocurrent in plasmonic nanostructure-diode-based devices.
Regulation of androgen receptor activity by tyrosine phosphorylation

The androgen receptor (AR) is essential for the growth of prostate cancer cells. Here, we report that tyrosine phosphorylation of AR is induced by growth factors and elevated in hormone-refractory prostate tumors. Mutation of the major tyrosine phosphorylation site in AR significantly inhibits the growth of prostate cancer cells under androgen-depleted conditions. The Src tyrosine kinase appears to be responsible for phosphorylating AR, and there is a positive correlation of AR tyrosine phosphorylation with Src tyrosine kinase activity in human prostate tumors. Our data collectively suggest that growth factors and their downstream tyrosine kinases, which are elevated during hormone-ablation therapy, can induce tyrosine phosphorylation of AR and such modification may be important for prostate tumor growth under androgen-depleted conditions.
Optical classification of bioaerosols using UV fluorescence and IR absorption spectroscopy

A partnership that includes the Naval Research Laboratory (NRL), MIT Lincoln Laboratories and the Edgewood Chemical and Biological Command is engaged in an effort to develop optical techniques for the rapid detection and classification of biological aerosols. This paper will describe two efforts at NRL: development of an improved UV fluorescence front-end trigger and the use of infrared absorption spectroscopy to classify biological aerosol particles. UV Laser-induced fluorescence (UVLIF) has been demonstrated to provide very high sensitivity for differentiating between biological and inorganic aerosol particles. Unfortunately, current UVLIF systems have unacceptably high false alarm rates due to interferences from man made and naturally occurring organic and biological particulates. We have developed a two-wavelength, UVLIF technique that offers a higher level of discrimination than is possible using single wavelength UVLIF. Infrared absorption spectroscopy coupled with multivariate analysis demonstrates a high potential for differentiation among members of biological and chemical sample classes. Two-wavelength UVLIF in combination with the IR interrogation of collected bioaerosols could provide a rapid, reagentless approach to specific classification of biological particles according to an operational level of discrimination - the degree of particle characterization required in order to signal the presence of pathogenic material.
The effects of exposure to conspecific urine on urine-marking in male and female degus (Octodon degus).

The urine-marking, defecation rates, and urine-sniffing behavior of male and female degus (Octodon degus) were recorded in an open field whose substrate was clean (Control Tests) or covered in conspecific urine (Experimental Tests). Animals were exposed to these conditions intermittently over a 3-mo period. Males urine-marked more than females. Both sexes exhibited increased levels of urine-marking and defecation during Control Tests as time passed. Males showed decreased urine-marking and defecation rates when exposed to the urine of conspecific males, but no changes in these behaviors with female urine. Females increased urinemarking rates when exposed to female urine, but exhibited no changes with male urine. The results are discussed with reference to degu social organization and the factors influencing scent-marking behavior.
Heterogeneity of response and survival in diffuse histiocytic lymphoma after BACOP therapy (bleomycin, doxorubicin, cyclophosphamide, vincristine, prednisone).

Diffuse ‘histiocytic’ lymphoma (DHL) is heterogeneous pathologically, consisting of four subtypes within Lukes–Collins; large-cleaved (LC), large non-cleaved (LNC), immunoblastic sarcoma of B cells (B-IBS), and immunoblastic sarcoma of T-cells (T-IBS). This heterogeneity is also recognized in the Cooperative Working Formulation on non-Hodgkin's lymphoma. Prior studies have suggested clinical heterogeneity of DHL as well, although conclusions were hampered by small numbers, and lack of therapeutic uniformity. We treated 57 patients with advanced DHL, using BACOP: 22 LNC, 16 T-IBS, 13 B-IBS, six LC. Complete remission rate for LNC was 64 per cent (14/22); B-IBS was 54 per cent (7/13); LC was 33 per cent (2/6); T-IBS was 25 per cent (4/16). (p=0.10). Median survival for LNC was 27.8 months, B-IBS was 25.9, LC was 14, T-IBS was 12.0. The survival was significantly shorter for T-IBS patients when compared to the others (p=0.01). By multi-variate analysis, histologic subtype (p=0.02), age (p=0.03), and stage (p=0.06) were significant and independent prognostic variables in predicting survival. We conclude that LNC may respond the most favourably to BACOP, whereas alternative regimens appear necessary for patients with T-IBS.
Isothermal Nucleation Rates in Supersonic Nozzles and the Properties of Small Water Clusters

We make direct measurements of stationary, homogeneous nucleation rates, J = N/Δt, in supersonic Laval nozzles. We determine the number densities, N, of droplets formed from small-angle neutron scattering (SANS) experiments and the time intervals during which nucleation occurs, Δt ≈10 μs, from static pressure measurements along the axis of the nozzle. Applying these techniques to nozzles with different expansion rates, we obtain the first isothermal nucleation rate measurements as a function of supersaturation for these devices with a relatively small error margin in J of ±50%. At temperatures T of 210, 220, and 230 K, the maximum nucleation rates for D2O lie in the range 4 × 1016< J/cm-3s-1 < 3 × 1017 for supersaturations S ranging from 46 to 143. At the highest temperature, the predictions of classical nucleation theory lie slightly below the experimental points but are still within experimental error. At the lower temperatures, the classical predictions lie well below the measured values. The discrepan...
Estrogen Regulation of Human Osteoblastic Cell Proliferation and Differentiation

Estrogen (E2) has been shown to prevent bone loss among postmenopausal women. The molecular mechanism(s) by which this is accomplished is not clear. The discovery of E2 receptor (ER) in osteoblasts and osteoclasts has implicated these cells as direct targets for E2. Previous studies on the effects of E2 on osteoblastic cells in vitro or in organ culture present conflicting results, possibly due to heterogeneity in cell types, stage of differentiation, ER levels, and/or species differences. The effects of E2 on gene expression during various stages of human osteoblast cell differentiation has not been investigated extensively. In this study we employed a newly developed human fetal osteoblastic cell line (hFOB/ER9) that contains high levels of ER to examine the effects of E2 on osteoblast proliferation and differentiation. The basal levels and E2 effects on the expression of various extracellular matrix proteins were also characterized throughout different stages of differentiation. These stages include a proliferative/relatively undifferentiated stage (day 6), a matrix maturation stage (days 10-14), and a mineralization/calcified nodule stage (day 18). During the stage of rapid cell proliferation, E2 treatment of hFOB/ER9 cells resulted in a dose-dependent decrease in [3H]thymidine incorporation to a maximum of 72% compared to the vehicle control value. Treatment of hFOB/ER9 cells with 10(-9) M E2 for 48 h resulted in an increase in alkaline phosphatase (AP) activity throughout cell differentiation. The magnitude of AP induction varied from approximately 200-500%. In contrast, E2 decreased osteocalcin protein levels to a minimum of 54% compared to the vehicle control value. The steady state messenger RNA levels for AP increased and osteocalcin decreased after E2 treatment, similar to the responses observed at the protein level. At all stages, there was little or no effect of E2 on type I collagen protein levels or osteonectin steady state messenger RNA levels. The E2 responses on hFOB/ER9 cell matrix protein expression and cell proliferation were mediated through the ER, as cultures cotreated with a 100-fold molar excess of a type II anti-E2 (ICI 182,780) abrogated these effects. These results support the hypothesis that E2 does have an effect on osteoblastic differentiation by decreasing hFOB/ER9 cell proliferation and differentially regulating extracellular matrix expression.
Inflammation in Alzheimer Disease—A Brief Review of the Basic Science and Clinical Literature

Biochemical and neuropathological studies of brains from individuals with Alzheimer disease (AD) provide clear evidence for an activation of inflammatory pathways, and long-term use of anti-inflammatory drugs is linked with reduced risk to develop the disease. As cause and effect relationships between inflammation and AD are being worked out, there is a realization that some components of this complex molecular and cellular machinery are most likely promoting pathological processes leading to AD, whereas other components serve to do the opposite. The challenge will be to find ways of fine tuning inflammation to delay, prevent, or treat AD.