cssi/SciSciGPT-SciSciNet huggingface dataset:
A Mobile Precursor Determines Amyloid-β Peptide Fibril Formation at the Liquid-Solid Interface

The aggregation of peptides into amyloid fibrils plays a crucial role in various neurodegenerative diseases, such as Alzheimer's disease and Parkinson's disease. While extensive work has been devoted to the study of solution fibril formation in vitro, the situation differs fundamentally from that in a living cell where the effect of macromolecular crowding provides a very large surface area surrounding peptide and protein molecules. Here we study the dynamics of fibril formation of Alzheimer's amyloid-β peptide, Aβ42, on nanoscopic patterned block copolymer films and self-assembly monolayer modified surfaces with different hydrophobicities. We report the discovery of that weakly adsorbed peptides with two-dimensional diffusivity is a critifcal precursor to fibril growth. A balance between mobility and transient concentration of the peptide precursor state determines the kinetics of fibril formation.
Explicit equations for the second Brewster angle of an interface between a transparent and an absorbing medium

The second Brewster angle ϕB2, at which the ratio ℛp/ℛs of intensity reflectances ℛp and ℛs for the parallel (p) and the perpendicular (s) polarizations of a dielectric–conductor interface reaches a minimum, is determined by Im[(u-∊)(u-∊¯)2/(u-2∊¯)2]=0, where ∊ is the complex ratio of dielectric constants of the media of refraction and incidence, ∊¯ = ∊/(∊ + 1), and u = sin2ϕB2. An equivalent quartic equation in u is also derived that can be solved exactly and explicitly to determine ϕB2 in terms of ∊.
Effects of a Supplemented Very Low Protein Diet in Predialysis Patients on the Serum Albumin Level, Proteinuria, and Subsequent Survival on Dialysis

A very low protein diet (0.3 g/kg ideal body weight) supplemented with essential amino acids (or ketoanalogues) is seldom employed at present in chronic renal failure for fear of inducing protein defi
Fate of Pentabrominated Diphenyl Ethers in Soil: Abiotic Sorption, Plant Uptake, and the Impact of Interspecific Plant Interactions

Polybrominated diphenyl ethers (PBDEs) are potentially harmful and persistent environmental pollutants. Despite evidence that soils are a major sink for PBDEs, little is known regarding their behavior in this medium. An environmentally relevant level of a commercial penta-BDE mixture (75 μg kg-1) was added to topsoil, and the extractability of three congeners (BDE-47, -99, and -100) was monitored over 10 weeks in planted and unplanted treatments. The extractability of each congener decreased rapidly in the experimental soil due largely to abiotic sorption to soil particles, which was demonstrated by low PBDE recovery from sterilized and dry soils. Monoculture plantings of zucchini and radish did not affect the recovery of PBDEs from soil. However, PBDE recovery from mixed species plantings was nearly 8 times higher than that of unplanted and monoculture treatments, indicating that interspecific plant interactions may enhance PBDE bioavailablity in soil. Evidence for competitive interactions between the tw...
Punishment modifies the effects of chlordiazepoxide and benzodiazepine receptors

Abstract Littermate groups of male albino rats responded under a procedure which generated comparable rates of punished and nonpunished responding. Chlordiazepoxide (3.0–30.0 mg/kg, IP) increased punished responding but had no effect on nonpunished responding. Homogenate receptor binding studies with [3H]Ro 15-1788 indicated increased benzodiazepine receptor binding in the striatum of rats who received shock. Moreover, a third group of rats exposed to noncontingent shock showed greater increases than those whose responses had been punished, suggesting that predictability and control of shock may have attenuated the effects of the noxious stimulus. Increased binding seen in the cerebellum, however, was related to the punishing effects of the electric shock since it occured only in those animals receiving response-contingent shock. There were no changes in binding affinity in any of the brain regions tested. Site-specific alterations in benzodiazepine receptors following electric footshock are related to the contigencies under which the noxious stimuli are administered. Furthermore, changes in benzodiazepine receptor binding may underlie the differential effects of benzodiazepine agonists on punished and nonpunished responding.
No More Corrections to the Topological Mass Term in QED in Three-Dimensions

We consider the theory of a photon interacting with scalar, spinor, and/or vector fields with arbitrary gauge-invariant interactions, in three spacetime dimensions. We show that to all orders in perturbation theory, all corrections to the topological mass term (beyond the known one-loop correction) vanish identically.
EMERGING STATE ROLES IN URBAN STORMWATER MANAGEMENT1

: The technology of urban stormwater management has far outpaced its actual application in new urban development. This article documents that implementation gap, but shows that state and local governmental measures, particularly storm drainage regulations, can lead to improved performance in the private sector. Although state stormwater management programs are in their infancy, they are already having a measurable effect in stimulating the adoption of local governmental programs to manage urban storm water. Pioneering state programs in Maryland, New Jersey, and Pennsylvania, described in this article, provide models for states contemplating the formulation of stormwater management programs.
Oximes as reversible links in polymer chemistry: dynamic macromolecular stars

We demonstrate the formation of oxime-functional macromolecular stars that are able to dissociate and reconstruct themselves upon application of a stimulus. The reversible nature of the oxime bond in the presence of externally added alkoxyamines or carbonyl compounds enables reconfiguration via competitive exchange. Reversible addition–fragmentation chain transfer (RAFT) polymerization was utilized to prepare well-defined amphiphilic block copolymers in which a hydrophobic keto-functional block allowed self-assembly into micelles in water. Adding a difunctional alkoxyamine small molecule to these solutions resulted in crosslinking of the micelles to yield macromolecular stars. The reversible nature of the O-alkyl oxime linkages was demonstrated via competitive exchange with excess of carbonyl compounds or monofunctional alkoxyamine under acidic conditions and at elevated temperatures to result in dissociation of the stars to unimolecular oxime-functional polymer chains.
Residential segregation and mortality in New York City

Abstract The objective of this research was to determine the effect of residential racial segregation on all-cause and cardiovascular disease mortality in New York City. A cross-sectional study of residents in New York City was conducted linking mortality records from 1988 through 1994, to the 1990 United States Census data stratified by zipcode. All-cause and cardiovascular disease mortality rates for non-Hispanic blacks and whites were estimated by zipcode. Zipcodes were aggregated according to the degree of residential segregation (predominantly (≥75%) white and black areas) and mortality rates were compared. Multiple regression analysis was used to associate population characteristics with mortality. In New York City, although overall mortality rates of blacks exceed whites, these rates varied substantially by locality according to the pattern of racial segregation. Whites living in the higher (mainly white) socioeconomic areas had lower mortality rates than whites living in predominantly black areas (1473.7 vs 1934.1 for males, and 909.9 vs 1414.7 for females for all-cause mortality). This was true for all age groups. By contrast, elderly blacks living in black areas, despite their less favorable socioeconomic status, had lower mortality rates for all-cause, total cardiovascular disease, and coronary heart disease, than did those living in white areas, even after adjusting for available socioeconomic variables. Racial segregation in residence is independently associated with mortality. Within racially segregated areas, members of the dominant group, for all age, among whites and elderly blacks, enjoy outcomes superior both to members of the minority racial group of their community, and to members of the same race residing in other areas, where they are in the minority, independent of socio-economic status.
0018 Validation of a wearable real-time monitor of exposure to naphthalene

Objectives Direct reading instruments are valuable tools for assessing exposure in the workplace. Adaption of such instruments to serve as valid and efficient tools to provide personal exposure data for environmental surveillance and occupational epidemiology studies fulfils a critical research need. Method A project is underway to validate new sensor technology that utilises native fluorescence of molecules excited by ultraviolet light with the goal of delivering laboratory-quality data for qualitative and quantitative analyses. The initial chemical of focus with this technology is naphthalene. The project is proceeding in two stages: independent laboratory validation and an exposure assessment field study, which is being conducted in two Phases: Phase I examines the degree to which the instrument serves as a sensor of naphthalene by assessing the concordance between measured personal air levels and those measured with conventional technologies e.g. active samplers; Phase II evaluates the validity of the instrument to serve as a dosimeter, correlating instrument-measured naphthalene levels in air with biological markers of exposure from skin, urine and exhaled breath. Results Independent laboratory evaluations indicate the instrument is accurate within accepted laboratory guidelines, when compared to standard gas chromatography methods. Results from the Phase I field study with US military personnel working with jet propulsion fuels (e.g., JP8 and jet A) as part of their regular work responsibilities support laboratory validation findings. Phase II data efforts are in progress. Conclusions This technology permits real-time evaluation of task-specific variations in personal naphthalene exposure levels, data that are currently not available with conventional active sampling processes.
Light-limited growth of two strains of the marine diatom Phaeodactylum tricornutum Bohlin: Chemical composition, carbon partitioning and the diel periodicity of physiological processes

Two isolates of the marine pennate diatom Phaeodactylum tricornutum Bohlin were grown in semi-continuous, nutrient-sufficient culture at varying irradiances on a 12-h light, 12-h dark illumination cycle. The reponse of the isolates to varying degrees of light limitation differed with respect to all of the compositional parameters measured, including growth rates, elemental composition, chlorophyll content, and the partitioning of cellular carbon into four biochemical classes: proteins, lipids, polysaccharides, and low-molecular weight intermediates. The isolates also differed with respect to the relative contributions of light-period and dark-period uptake to the total uptake of ammonium and phosphate ions, although in all cases uptake took place at a reduced rate in the dark. They did not differ with respect to the diel periodicity of cell division, chlorophyll synthesis, and biochemical synthesis. Slightly more cell division took place during the dark period than during the light period. The specific rate of chlorophyll synthesis in the light period, when expressed as a function of irradiance, saturated rapidly; the rate was nearly constant for all irradiances > 100 βE · m−2 · s−1. Chlorophyll synthesis in the dark was positively correlated with irradiance over the entire range of irradiances, except where photoinhibition was involved. Protein was synthesized in both the light and dark periods, but at a reduced rate in the dark. Polysaccharides were synthesized during the light period and consumed during the dark period. Lipids and low molecular weight intermediates were synthesized during the light period, but showed little net change during the dark period.
Bilayer Hydrogel With Autologous Stem Cells Derived From Debrided Human Burn Skin for Improved Skin Regeneration

The objective of this study was to demonstrate that stem cells isolated from discarded skin obtained after debridement can be used with collagen and fibrin-based scaffolds to develop a tissue-engineered vascularized dermal equivalent. Discarded tissue samples were collected from severely burned patients undergoing wound debridement. Stem cells were isolated from the adipose tissue layer and their growth and immunophenotype characterized. To develop a skin equivalent, debrided skin adipose stem cells (dsASCs) were added to a collagen-polyethylene glycol (PEG) fibrin-based bilayer hydrogel and analyzed in vitro. The effect of the bilayered hydrogels on wound healing was demonstrated using an excision wound model in athymic rats. The dsASCs isolated from all samples were CD90, CD105, and stromal cell surface protein-1 positive, similar to adipose stem cells isolated from normal human lipoaspirates. Within the bilayer hydrogels, dsASCs proliferated and differentiated, maintained a spindle-shaped morphology in collagen, and developed a tubular microvascular network in the PEGylated fibrin. Rat excision wounds treated with bilayer hydrogels showed less wound contraction and exhibited better dermal matrix deposition and epithelial margin progression than controls. Stem cells can be isolated from the adipose layer of burned skin obtained during debridement. When dsASCs are incorporated within collagen-PEGylated fibrin bilayer hydrogels, they develop stromal and vascular phenotypes through matrix-directed differentiation without use of growth factors. Preliminary in vivo studies indicate that dsASC-bilayer hydrogels contribute significantly to wound healing and provide support for their use as a vascularized dermal substitute for skin regeneration to treat large surface area burns.
Prevention of acute renal failure

Abstract Acute renal failure is a common occurrence in the contemporary practice of medicine, and current mortality rates range from 10% to 80%. Practical measures to prevent acute renal failure in hospitalized patients include aggressive resuscitation of traumatized patients, careful vigilance to maintain adequate circulating blood volume and renal perfusion, avoidance of nephrotoxins, and selective use of volume expansion and forced diuresis.
Asymmetric synthesis of threo β-hydroxy-α-N-methyl amino acids and MeBMT analogs via epoxides1. (Part 1)

Abstract Threo 2-oxazolidinones 5, readily available by regiospecific intramolecular opening of cis-epoxyurethanes 4, were utilized for the synthesis of β-hydroxy-α-N-methyl amino acids. New analogs of the cyclosporine amino acid, MeBmt, are made possible by this route.
Preference for immediate reinforcement in depression

Abstract In order to test predictions derived from Lewinsohn's behavioral analysis of depression, 92 undergraduates were given paper and pencil measures of depression, preference for immediate vs delayed reinforcement and value of social vs non-social reinforcements. Results indicated that more depressed S s scored more in the direction of preferring immediate reinforcement and that this did not seem to be due to response bias. Depression was not related to social vs non-social reinforcer preference. Results were discussed in relation to the function of depressive behavior.
Extended lattice filters enabled by four-directional couplers

Novel lattice-filter structures consisting of four-directional couplers are introduced, analyzed, and discussed. Four-directional couplers are discussed, and energy-conservation relations in a field-wave application are derived. A thick linear lattice filter is presented and studied as a simple extension to the traditional lattice. A two-dimensional lattice structure is also introduced and studied. Transfer functions are derived and discussed for several examples.
The Effect of Reverse Protein and Low Protein Feeding Regimens in the Rearing Period on Pullet Growth, Subsequent Performance, and Liver and Abdominal Fat at End of Lay

Abstract Four brown egg strains were used to study the effect of rearing diets on growth and performance. The treatments were arranged in a 4 × 3 factorial with two replicates of 45 birds. The control diet was formulated and fed to National Research Council recommendations. Birds on reverse protein (RP) were fed diets with 13, 16, and 19% protein and those on low protein (LP) regimen received a 13.5% protein diet with amino acids adjusted on a megacalorie basis to approximate the control diet. At 20 week s of age pullets were caged and fed a standard layer diet. Logistic curves were fitted to the growth data by a nonlinear least squares method and the parameters of each curve analyzed. No significant strain × diet interactions were observed. There were significant differences among strains in weight gain and feed intake. Dietary regimens had no significant effect on total gain and feed intake. However, diets significantly altered age at one-half maximum growth or inflection point (α) and mean growth rate (ρ). Inflection point of the growth curve was significantly delayed in birds fed RP and LP diets. Although apparent conversion was not affected by diets, the partition coefficients at any time (t) for maintenance (βmt) and gain (βgt) were altered. Neither strain nor dietary regimens affected abdominal fat or organ weights at the end of the rearing period. No significant effect of rearing dietary regimens was detected in age at 50% production or peak production, feed conversion, feed intake, livability, liver fat, abdominal fat, or shell strength. The reverse-protein regimen significantly depressed egg weight. The results of the study indicate that 1) the rearing dietary regimens were adequate for strains of different body weight and egg output characteristics; 2) dietary alteration of growth curve (parameters failed to influence production, feed intake, mortality, shell strength, livability, liver fat, or abdominal fat during the production period.
Cow's milk allergy, incidence and pathogenetic role of early exposure to cow's milk formula.

A study was performed in infants under the age of 12 months born during 1974 and admitted to St. Goran's Children's Hospital with symptoms suggestive of cow's milk allergy (CMA). The aims of the study were to determine the role of early exposure to cow's milk formulas as a predisposing factor to CMA and to estimate the incidence of CMA in infancy. Twenty-five infants fulfilled the criteria for CMA. Available records were reviewed and a careful history was obtained from the mothers on two occasions. The patient group was compared with a control group. Sixteen of the 25 infants were exposed to cow's milk protein during their first week in the nursery for newborns, 6 were exposed before the end of the fourth week of life, and 3 infants were apparently not exposed. All infants were breast fed 3 to 26 weeks before re-exposure and occurrence of symptoms. Infants with CMA were given cow's milk formulas during their first 4 weeks of life significantly more often than infants in the control group (p less than 0.01). The incidence of CMA was approximately 1 : 200. The first 4 weeks after birth seem to be a particularly vulnerable period. Hence, in order to prevent CMA, infant formula should not be given--even occasionally--during this period.
Analysis of Supercritical Startup Behavior for Cryogenic Heat Pipes

A theoretical analysis was conducted to describe the startup process from the supercritical state for axially grooved cryogenic heat pipes. Using an approximation method, a heat-balance integral solution was developed to predict the rewetting velocity, liquid front position, and transient axial temperature distributions for axially grooved cryogenic heat pipes. The developed model assumes an initially uniform axial temperature distribution and divides the startup process into two characteristic regions, based on whether a liquid column is established in the condenser region. The predicted transient temperature profiles of two cryogenic oxygen heat pipes were in good agreement with previous experimental microgravity flight data. Nomenclature A = coefficient defined in Eq. (12) Af = cross-sectional area of the working fluid AI = cross-sectional area of the liquid channel As = cross-sectional area of the heat-pipe wall B = coefficient defined in Eq. (12) Ce = effective heat capacity c - specific heat D = coefficient defined in Eq. (12) Dh = hydraulic diameter E = thermal energy F = force h = groove thickness hfg = latent heat of liquid-vapor phase change k = thermal conductivity La = length of adiabatic section Lc = length of condenser Le = length of evaporator P = internal pressure Pc = critical pressure Pr = reduced pressure R = gas constant Re = Reynolds number r = capillary radius T = temperature Tc = critical temperature Tcond = condenser temperature Tr = reduced temperature 7*0 = initial temperature t - time U = liquid mean velocity Ur = liquid rewetting velocity v = specific volume of vapor w = groove width z = compressibility factor ae = effective heat diffusivity j8 = coefficient defined in Eq. (3) 8 = penetration depth e = liquid layer length
“At once mild and animating”: Prometheus Unbound and Shelley’s Spell of Style

In this essay I argue that key aspects of Prometheus Unbound’s style can be understood as a form of poetic spell‐casting. Passages throughout the drama display the characteristic features of the spell: language is treated as a physical action, and sonic and rhythmic devices based on repetition are prominent. Furthermore, these features yield the kind of “compelling” effect that has been associated with the spell. In Shelley’s work, this effect is to overwhelm the reader with a physical experience of the text, but also, crucially, to instill the drama’s primary revolutionary values in the reader through the dynamics of sensory language. This transfer occurs, I argue, through two main forms of spell‐like language in the drama, which can be termed the hypnotic and sublime styles. Appearing in key passages throughout Acts 2 and 4, each of these styles has specific characteristics. In both styles, however, sonic, rhythmic, and visual dynamics ultimately serve as a concrete illustration of hope, endurance, and ...
Meson + Hyperon Final States in K - p Interactions at 4.1 and 5.5 GeV/c

Differential cross sections for reactions of the type ${K}^{\ensuremath{-}}+p\ensuremath{\rightarrow}\mathrm{n}\mathrm{e}\mathrm{u}\mathrm{t}\mathrm{r}\mathrm{a}\mathrm{l}\phantom{\rule{0ex}{0ex}}\mathrm{h}\mathrm{y}\mathrm{p}\mathrm{e}\mathrm{r}\mathrm{o}\mathrm{n}+\mathrm{n}\mathrm{e}\mathrm{u}\mathrm{t}\mathrm{r}\mathrm{a}\mathrm{l}\phantom{\rule{0ex}{0ex}}\mathrm{m}\mathrm{e}\mathrm{s}\mathrm{o}\mathrm{n}$ have been measured. The cross sections for peripheral production of vector mesons satisfy certain relations yielded by the independent quark model and other symmetry schemes. The cross section for meson production in the backward hemisphere provides some information on the presence of various baryon-exchange processes.
Trajectory calculations for axial injection of ions into a magnetic field: overcoming the magnetic mirror effect with an r.f. quadrupole lens

Abstract The magnetic mirror effect is one of the problems that must be overcome in order to perform Fourier transform mass spectrometry (FT-MS) experiments with an external ion source. Since the ion source is located outside of the magnetic field, about 1 m from the FT-MS analyzer cell, some type of focusing is needed to guide the ions through the fringing fields of the magnet. Several years ago, McIver and co-workers showed that a quadrupole lens operated in the r.f.-only mode was an effective means for accomplishing this. In this paper, the theory of ion injection by a r.f. quadrupole lens is developed and trajectory calculations are performed to determine how the mass range of the quadrupole lens depends on the frequency and low voltage of the signal that is applied to the rods. The calculations show that the quadrupole lens functions like a broadband filter with certain low mass and high mass cut-offs. By selecting the proper operating conditions, the mass range of the injection ions can extend over several thousand mass units and high mass ions (m/z greater than 20 000) can be injected.
Effects of food restriction and insulin treatment on (Ca2+ + Mg2+)-ATPase response to insulin in kidney basolateral membranes of noninsulin-dependent diabetic rats.

Insulin increases (Ca2+ + Mg2+)-ATPase activity in cell membranes of normal rats but fails to do so in membranes of non-insulin-dependent diabetic (NIDD) rats. The loss of regulatory effect of the hormone on the enzyme might contribute to the insulin resistance observed in the NIDD animals. To further test this hypothesis, the effects of insulin treatment and acute food restriction on the ability of insulin to regulate the ATPase activity in kidney basolateral membranes (BLM) of NIDD rats were studied. Although insulin levels in NIDD and control rats were similar, plasma glucose was higher in the NIDD rats (18.3 ± 1.5 v 19.3 ± 1.7 μU/mL and 236 ± 32 v 145 ± 3 mg/dL, respectively). Insulin treatment (2 U100 g), which increased plasma insulin in the NIDD rats (47.8 ± 11.5 μU/mL; P < .05), did not decrease their glucose (221 ± 25 mg/dL). Higher insulin dose (4 U100 g) decreased glucose level in the NIDD rats (73 ± 3 mg/dL; P < .001) but increased their plasma insulin 10-fold (202.5 ± 52.5 μU/mL). Acute food restriction decreased glucose levels in the NIDD rats to levels seen in controls (135 ± 3 mg/dL), while their insulin decreased by half (8.5 ± 1.0 μU/mL; P < .05). Basal (Ca2+ + Mg2+)-ATPase activity in BLM of all diabetic rats was higher than in controls (P < .05). None of the treatments reversed this defect. Insulin (12.5 to 200 μU/mL) increased the ATPase activity (10% to 40%) in BLM from controls but not from NIDD rats. In BLM from food-restricted diabetic rats, insulin increased the enzyme activity by 16% to 42%, but the dose-response curve was shifted to the right. In BLM from insulin-treated rats, insulin caused a slight (10% to 20%) increase in enzyme activity only at its highest concentration (200 μU/mL). These findings confirm the existence of insulin resistance in the NIDD rats and reveal that acute food restriction ameliorates it. The amelioration of insulin resistance was accompanied by a regained ability of insulin to regulate the membrane (Ca2+ + Mg2+)-ATPase. It is suggested that part of the beneficial effect of food restriction on insulin resistance in the NIDD rat is due to a restoration of insulin's ability to regulate cell Ca2+ homeostasis.
Net Margins from Different Fractions of Holstein Genes in Venezuelan Herds Based on Performance Estimates by Producers and Advisors

Abstract The objective was to estimate the profitability of different fractions of Holstein genes from subjective predictions of milk yield, calving interval, calf mortality, and length of productive herd life by Venezuelan producers and others for an upgrading program from a Zebu breed to Holstein. Data were from surveys of 157 farms in 1987 to 1988 to obtain input use; variable costs for feed, labor, health and reproduction; product prices; and market values by animal category. Predictions of performance in multiple traits were from a complementary survey of the same producers and others (16 consultants and 10 Venezuelan professors; 9 US germplasm exporters, and 17 US professors). Profit was approximated by lifetime net margin (gross income from milk plus male and female offspring plus salvage value minus variable costs) per cow for each breed group and discounted to the date of first calving. Survey respondents predicted that the 75% Holstein breed group was most profitable and that milk yield and calving interval were the most important traits economically. For net margin equal to 75% Holstein, 100% Holstein cows would have to increase milk yield by 23% or reduce calving intervals by 17%, and 50% Holstein cows would have to increase milk yield by 18% or reduce calving intervals by 12% to obtain profits equal to 75% Holstein. Most literature reports show differences in milk yield of less than 10% between 50 and 75% Holstein groups. Thus, 50 to 75% Holstein crosses are likely the most profitable ones when multiple traits were considered for Venezuelan conditions.
Gene expression profiling of a mouse model of pancreatic islet dysmorphogenesis

Background In the past decade, several transcription factors critical for pancreas organogenesis have been identified. Despite this success, many of the factors necessary for proper islet morphogenesis and function remain uncharacterized. Previous studies have shown that transgenic over-expression of the transcription factor Hnf6 specifically in the pancreatic endocrine cell lineage resulted in disruptions in islet morphogenesis, including dysfunctional endocrine cell sorting, increased individual islet size, increased number of peripheral endocrine cell types, and failure of islets to migrate away from the ductal epithelium. The mechanisms whereby maintained Hnf6 causes defects in islet morphogenesis have yet to be elucidated. Methodology/Principal Findings We exploited the dysmorphic islets in Hnf6 transgenic animals as a tool to identify factors important for islet morphogenesis. Genome-wide microarray analysis was used to identify differences in the gene expression profiles of late gestation and early postnatal total pancreas tissue from wild type and Hnf6 transgenic animals. Here we report the identification of genes with an altered expression in Hnf6 transgenic animals and highlight factors with potential importance in islet morphogenesis. Importantly, gene products involved in cell adhesion, cell migration, ECM remodeling and proliferation were found to be altered in Hnf6 transgenic pancreata, revealing specific candidates that can now be analyzed directly for their role in these processes during islet development. Conclusions/Significance This study provides a unique dataset that can act as a starting point for other investigators to explore the role of the identified genes in pancreatogenesis, islet morphogenesis and mature β cell function.
Gauge-invariant spin glasses.

Spin-glass models with orthogonal and unitary bond interactions are investigated using replica mean-field theory. The orthogonal model leads to a low-temperature phase described by a Parisi replica symmetry broken order parameter. The analogous solution for the unitary model is unstable to fluctuations which render the order parameter complex. In this case a simple parametrization of the Hermitian order parameter suggests a first-order transition.
Electrochemical excitation method in kinetic study of Ag2S

Abstract A steady-state electrochemical method of sinusoidal excitation has been developed in which the chemical diffusion coefficient of an atomic species in a solid is obtained via the determination of the spatial distribution of the phase and amplitude of its chemical potential oscillation. It has been applied to Ag 2+δ S to measure the chemical diffusion coefficient D of Ag in α-Ag 2+δ S at 168°C and in β-Ag 2+δ S at 220°C, with a typical precision of 0.2%. The measurements were performed at frequencies from 0.02 to 0.16 Hz, with δ covering the whole nonstoichiometry range. The values of D measured fell between 0.01 and 0.15 cm 2 /s at 168°C and between 0.08 and 0.32 cm 2 /s at 220°C, changing significantly with f but slightly with f. The component diffusion coefficient of Ag + was determined for β-Ag 2+δ S to be in the range of 3.0 to 3.6×10 −5 cm 2 /s, decreasing with a frequency dependence with increasing δ.
Beams of Gravitationally Bound Ultracold Neutrons in Rough Waveguides

We investigate the propagation of ultracold neutrons through a rough waveguide in conjunction with recent experiments in which the ultracold neutrons were beamed between a perfect mirror and a rough scatterer and absorber. The main goal is to find a way to resolve the lowest gravitationally quantized discrete states in the peV range. We compare the neutron count for various types of mirrors with Gaussian, power-law, and exponential correlation functions of surface inhomogeneities. The main conclusion is that all the information about inhomogeneities, including their amplitude, correlation radius, and the rate of decay of the correlation function, enter the exit neutron count via just a single constant $\ensuremath{\Phi}$, which effectively renormalizes the amplitude of roughness. To observe well-defined quantum steps, one should have an experimental setup with $\ensuremath{\Phi}g40$. For a wide variety of correlation functions, the constant $\ensuremath{\Phi}$ is proportional to the square of the amplitude of the surface roughness and is inversely proportional to the square root of the correlation radius. The strong dependence of $\ensuremath{\Phi}$ on roughness parameters and the shape of the correlation function opens a novel way for improving the resolution of gravitationally bound states by optimizing the roughness pattern without reverting to an undesirable strong roughness. We discuss how to optimize the scatterer and absorber by first generating numerically the desired roughness profile and then transferring it to the mirror. We also study the effect of beam preparation on the initial occupancies of gravitational states before the beam enters the waveguide. It turns out that there are simple ways to manipulate the beam in front of the waveguide that can help to resolve the gravitationally bound quantum states. Our results are in good agreement with available experimental data.
Using circular dichroism spectra to estimate protein secondary structure

Circular dichroism (CD) is an excellent tool for rapid determination of the secondary structure and folding properties of proteins that have been obtained using recombinant techniques or purified from tissues. The most widely used applications of protein CD are to determine whether an expressed, purified protein is folded, or if a mutation affects its conformation or stability. In addition, it can be used to study protein interactions. This protocol details the basic steps of obtaining and interpreting CD data, and methods for analyzing spectra to estimate the secondary structural composition of proteins. CD has the advantage that measurements may be made on multiple samples containing < or =20 microg of proteins in physiological buffers in a few hours. However, it does not give the residue-specific information that can be obtained by x-ray crystallography or NMR.
Structure of Py·Pu·PyDNA triple helices. Fourier transforms of fiber‐type x‐ray diffraction of single crystals

Well-formed hexagonal crystals of oligomeric DNA triple helices exhibit fiber-type x-ray diffraction patterns [cf., Liu et al. (1994) Nature Struct. Biol. 1, 11], which can be interpreted in terms of Fourier transforms of these helices. Precession photographs of a triplex formed of dA and dT chains show that it has 13 residues per turn. In contrast, a sequence containing the four natural bases A, G, C, and T has 12 residues per turn. In this sense the triple helices exhibit a sequence-dependent polymorphism, though both have C2'-endo sugar pucker and B rather than A conformation. New models are constructed, using constraints from x-ray diffraction, and Fourier transforms of the models are calculated. Good agreement in the amplitudes and positions of the calculated and observed diffraction intensities confirms the structures for both triple helices. These are the first stereochemically satisfactory DNA triple helices for which coordinates based on adequate experimental data were provided. Sequences for crystallization are designed to achieve unique base alignments and are screened for the presence of sharp bands on gel electrophoresis to assure the absence of multiple species caused by strand slippage. Despite intensive efforts to observe normal crystal diffraction by varying sequences and conditions, all crystals exhibited only fiber-type diffraction. We suggest that this behavior may be an intrinsic property of triple helices and discuss possible reasons for the results. Spectroscopic and chemical experiments establish that the oligonucleotides exist in solution as triple helices under the conditions of crystallization.
Walleye Prey Selection in Lake McConaughy, Nebraska: A Comparison between Stomach Content Analysis and Feeding Experiments

Abstract We investigated walleye (Stizostedion vitreum) prey selection by comparing results from feeding experiments and stomach content analysis. Walleye captured from Lake McConaughy, Nebraska in June through September, 1995, were presented treatments of three prey species-yellow perch (Perca flavescens), white sucker (Catostomus commersoni) and either alewife (Alosa pseudoharengus) or gizzard shad (Dorsoma cepedianum). In the feeding experiments, walleye selected white sucker and yellow perch over alewife and gizzard shad. However, alewife were the most abundant prey species in walleye stomachs and not significantly different from their proportion in the natural prey fish assemblage. Differences in prey selection between experiments and field studies suggest that walleye altered their foraging behavior to take advantage of vulnerable or more accessible prey.
Leucine enkephalin: localization in and axoplasmic transport by sacral parasympathetic preganglionic neurons

Nerve processes and cell bodies containing leucine enkephalin were demonstrated in the sacral autonomic nucleus of the cat by immunocytochemical methods. Enkephalinergic preganglionic perikarya were seen only when axonal transport was blocked either by colchicine or by ventral root ligation. Ligation of the sacral ventral roots also produced damming of enkephalin immunoreactivity proximal to the S2 ligature. These data indicate that parasympathetic preganglionic neurons synthesize and transport enkephalin or enkephalin-like immunoreactive compounds to the periphery.
Ratiometric measurement and identification of single diffusing molecules

Abstract The concept of ratiometric identification and separation of sub-populations of single biomolecules which are labeled with individual fluorophores and are freely diffusing (or flowing) through the laser excitation volume is introduced. The efficacy of the scheme versus the signal and noise level is considered and a general theoretical framework and data analysis schemes are introduced. Experimental results that demonstrate distributions of single molecule fluorescence polarization anisotropy (smFPA) and single pair fluorescence resonance energy transfer (spFRET) in solution are presented. Ultimate resolution for identifying molecular observables such as conformational states, degree of freedom of motion and spectral distribution are discussed.
Effects of changes in data reporting practices on trend assessments

This paper illustrates inhomogeneities in pollutant time-series data caused by changes in data reporting practices. These inhomogeneities may have a substantial effect on trend assessments. Therefore, in estimating trends or mean levels in pollutant time series or attributing changes in pollutant levels to an emission control policy, it is important to homogenize time-series data.
Theory of isomerization equilibrium in electrophoresis. II.

The system of differential equations describing the electroophoretic transport of two-component isomerizing systems, AB, has been solved by numerical solution of the corresponding difference equations. The calculated schlieren patterns agree with those obtained by Scholten (2) using a different method of computation. A novel feature of the results is that the schlieren patterns may show three peaks under certain conditions of rates of reaction and time of electrophoresis.
Health disparities in pediatric cochlear implantation: an audiologic perspective.

Objectives: A national survey of pediatric cochlear implantation (PCI) audiologists was conducted with three aims: (1) to determine if PCI audiologists perceive within their clinical practice a negative effect of low socioeconomic status (SES) on postimplant speech and language outcomes; (2) to understand their perceptions of the underlying factors leading to outcome disparities; and (3) to elicit suggestions for improving outcomes in disadvantaged populations. We hypothesized that audiologists would perceive reduced speech and language outcomes within their lower SES patient population, and that this noted disparity would be related to parental adherence (compliance) and access to habilitation. Design: A survey containing 22 quantitative and open-ended questions was electronically mailed to a data base of 234 PCI audiologists. Forty-four percent (N = 103 of 234) responded to the survey, with the majority (98 of 103) answering all questions. Quantitative responses were analyzed using the Stata 9 statistical package with significance at p < 0.05. Qualitative responses were analyzed using standardized codebook and content analysis. Transcripts were read and coded for the main ideas expressed in each response. The codes were then analyzed for patterns and organized into subthemes that were then grouped into themes. Results: Seventy-eight percent (N = 76 of 98) of respondents perceived an effect of SES on postimplant speech and language outcomes. Qualitative responses uniformly demonstrated audiologists' perception that lower SES patient populations were more likely to experience reduced speech and language outcomes. Two major themes emerged in audiologists' explanations of SES-related disparities: internal factors of parental influence (i.e., parental self-efficacy, adherence, and habilitation carryover), and external factors (i.e., inadequate therapy and lack of available resources). Three primary suggestions were offered for reducing the disparity: improvement in cochlear implant services (92%), increased emphasis on parental education and intervention (87%), and the development of stricter candidacy requirements (15%). Conclusions: This study offers evidence to show that PCI audiologists note an SES-related disparity in the field of PCI. Respondents suggest the need for a broad and culturally sensitive effort to both increase access to qualified healthcare professionals and develop approaches that will aid parents in the at-home habilitation process.
Measurement of Tension in a String Using an Array of Capacitive Force Sensors

The measurement of tension in strings and soft tissues is of critical importance in many applications, including orthopedic surgeries. Various sensors have previously been designed for the measurement of tension, but they all require either attachment of the sensor to the string or the use of an external-inertial reference. This paper presents two new sensors to estimate tension in strings without the need for attaching any devices on the string or a need for an inertial reference. Both sensors employ an array of three capacitive force measurement devices and estimate the tension based on these three readings. Experimental data show that the sensors can measure tension values up to 100 N on a bench-top test rig.
Hot-hardness comparisons among isostructural Be12X intermetallic compounds

Hot hardness has been measured in seven isostructural Be[sub 12]X compounds: Be[sub 12]Cr, Be[sub 12]Mn, Be[sub 12]V, Be[sub 12]Mo, Be[sub 12]Ti, Be[sub 12]Ta and Be[sub 12]Nb. All vacuum-hot-pressed (VHP) materials exhibited similar hardness levels (800 to 1000 kg/mm[sup 2]) at low temperatures ([lt]600 [degree]C), but sharply diverged at higher temperatures. Most compounds showed a sharp decrease in hardness above about one-half their melting temperatures except for Be[sub 12]Nb and Be[sub 12]Ti which maintained strength until higher temperatures. Ductile-brittle transition temperatures (DBTT's) of 600, 625, 690, 700, 700 and 850 [degree]C were determined for Be[sub 12]Cr, Be[sub 12]Mn, Be[sub 12]V, Be[sub 12]Mo, Be[sub 12]Ti and Be[sub 12]Nb, respectively. Hot-isostatically pressed (HIP) and VHP Be[sub 12]Nb heats both showed comparable behavior, indicating that the temperature required for macroscopic plasticity is not dependent on processing conditions. Differences in slip characteristics were observed between beryllides with similar melting temperatures, but differing DBTT's. Dislocations were activated on multiple slip systems in Be[sub 12]V during compressive deformation at 800 [degree]C. Similar behavior was not observed in Be[sub 12]Nb until test temperatures above 1000 [degree]C. It is proposed that dislocation mobility may be related to the stability between Be[sub 12]X and Be[sub 17]X[sub 2] phases. Larger refractorymore » metal atoms such as Nb may form faulted layers related to Be[sub 17]X[sub 2] structures and thereby impede deformation at intermediate temperatures. Smaller atoms such as Cr, Mn, V and Mo do not form a stable Be[sub 17]X[sub 2] phase and thereby allow enhanced dislocation mobility at these temperatures.« less
Pentobarbital prevents the development of C-fiber-induced hyperalgesia in the rat

Abstract Noxious stimuli applied to the skin can produce long-lasting, C-fiber-dependent, secondary hyperalgesia that is mediated by central mechanisms. NMDA receptor antagonists and low doses of morphine can preferentially block the development of hyperalgesia without significantly altering unpotentiated responses to nociceptive stimuli. The aim of our study was to determine if low doses of pentobarbital can also preferentially alter either hyperalgesic or unpotentiated responses to nociceptive heat stimuli in spinalized and intact rats. Our results demonstrate the following. 1. (1) Mustard oil applied above the ankle joint or electrical stimulation of the sciatic nerve at C-fiber intensity in spinalized, unanesthetized rats decreased the latency to withdrawal of the foot from water maintained at 47–49°C. This secondary hyperalgesia to thermal stimulation persisted for at least 1 h and was most likely mediated by central mechanisms. 2. (2) Pentobarbital in both spinalized and spinal cord-intact rats prevented the development of the late component (42–120 min) but only partially decreased the early (2–6 min) component of hyperalgesia. In contrast, pentobarbital had relatively minimal effects on unpotentiated withdrawal responses. Thus, pentobarbital is similar to morphine in its ability to prevent hyperalgesia, but may differ from the anesthetic isoflurane, which does not interfere with the development of hyperalgesia.
Phase transfer catalyzed depolymerization of poly(2,6-dimethyl-1,4-phenylene oxide) in the presence of either 2,4,6-trimethylphenol or 4-tert-butyl-2,6-dimethylphenol

This paper describes the phase transfer catalyzed depolymerization of poly(2,6-dimethyl-1,4-phenylene (xide) performed in the presence of either 2,4,6-trimethylphenol or 4-tert-butyl-2,6-dimethylphenol. The structure of the resulting polymers is compared to that of the corresponding polymers obtained by the phase transfer catalyzed polymerization of 4-bromo-2,6-dimethylphenol in the presence of either 2,4,6-trimethylphenol or 4-tert-butyl-2,6-dimethylphenol. Polymers obtained by depolymerization display a bimodal molecular weight distribution while those obtained by polymerization a monomodal molecular weight distribution. The polymers obtained by direct polymerization present structural units derived from some side reactions. These side reactions do not occur during the depolymerization process.