cssi/SciSciGPT-SciSciNet huggingface dataset:
Permeation, sorption, and diffusion of water in ethyl cellulose

The permeability of ethyl cellulose to water vapor and liquid water was measured as a function of temperature. A change of slope was found in the Arrhenius plots at about 50°C., close to the glass transition. The sorption isotherms showed essentially zero heat of mixing in agreement with other workers. The diffusion constants were measured in four ways, viz., sorption, desorption, time lag, and by dividing the permeability constants by the equilibrium solubility coefficients. The time lag method gave diffusion constants which were independent of concentration, whereas the other three methods led to diffusion constants which steadily decreased with concentration. All the methods, however, extrapolated to about the same value at zero concentration. The decreasing diffusivities are believed to be due to the clustering of water molecules in the polymer. However, no clustering appeared to take place under the conditions of the time lag measurements.
Side-information-adaptive distributed source coding

Consider distributed source coding in which each block of the source at the encoder is associated with multiple candidates for side information at the decoder, just one of which is statistically dependent on the source block. Our encoder codes the source as syndrome bits and also sends a portion of it uncoded as doping bits. The decoder adaptively discovers the best side information candidates for each block of the source. The main contribution is a method based on density evolution to analyze and design the coding performance. Experimental results show that the density evolution technique is accurate in modeling the codec and optimizing its doping rate.
The Case Against Mass E-mails: Perverse Incentives and Low Quality Public Participation in U.S. Federal Rulemaking

Large-scale e-mail campaigns are a staple in the modern environmental movement. Interest groups increasingly use online mobilizations as a way to raise awareness, money, and membership. There are legitimate political, economic, and organizational reasons for doing so, but these gains may come at the expense of a more substantial and efficacious role for citizens who wish to use e-mail to engage in public participation. This paper situates a close examination of the 1000 longest modified MoveOn. Org-generated e-mails sent to the Environmental Protection Agency (EPA) about its 2004 mercury rulemaking, in the broader context of online grassroots lobbying. The findings indicate that only a tiny portion of these public comments constitute potentially relevant new information for the EPA to consider. The vast majority of Move On comments are either exact duplicates of a two-sentence form letter, or they are variants of a small number of broad claims about the inadequacy of the proposed rule. This paper argues that norms, rules, and tools will emerge to deal with the burden imposed by these communications. More broadly, it raises doubts about the notion that online public participation is a harbinger of a more deliberative and democratic era.
Correlating solvation free energies and surface tensions of hydrocarbon solutes

A simple equation relating ratios of transfer free energies and solvation free energies to surface tension is derived. When applied to hydrocarbons in water, experimental values for macroscopic surface tension yield remarkably accurate predictions of a ratio involving microscopic quantities, if one uses transfer free energies which have been adjusted for the effects of solute/solvent volume differences. The results support the validity of applying macroscopic concepts such as interfacial free energy at the molecular level. They further suggest that molecular volume as well as surface area contributes to the solubility of hydrocarbons in water.
A starch block electrophoresis study of aqueous house dust extracts

Abstract 1.1. The approximate chemical compositions of four dust extracts, including the Hollister-Stier and Endo commercial preparations and two extracts prepared in our laboratory, were determined. These materials were found to consist of a heterogeneous mixture of acidic polysaccharides with varying amounts of polypeptide. 2.2. The materials were investigated by starch block electrophoresis in acetate buffer (pH 4.7, μ = 0.1). In general, a fast (negatively charged) and a slow peak were found. The allergen activity was predominately associated with the materials of slow or intermediate mobility. In some cases the fractions seemed to be more active than the unfractionated extract. 3.3. No simple relation was evident between the monosaccharide composition or the nitrogen content of the fractions and the allergen activity. 4.4. The color moved slightly faster than the fast peak and was definitely separated from the more active fractions. 5.5. Experiments were presented that indicated that the polypeptide moiety of the dust extract was linked to the polysaccharides by covalent bonds.
Integrating Satellite Imagery with Simulation Modeling to Improve Burn Severity Mapping

Both satellite imagery and spatial fire effects models are valuable tools for generating burn severity maps that are useful to fire scientists and resource managers. The purpose of this study was to test a new mapping approach that integrates imagery and modeling to create more accurate burn severity maps. We developed and assessed a statistical model that combines the Relative differenced Normalized Burn Ratio, a satellite image-based change detection procedure commonly used to map burn severity, with output from the Fire Hazard and Risk Model, a simulation model that estimates fire effects at a landscape scale. Using 285 Composite Burn Index (CBI) plots in Washington and Montana as ground reference, we found that an integrated model explained more variability in CBI (R2 = 0.47) and had lower mean squared error (MSE = 0.28) than image (R2 = 0.42 and MSE = 0.30) or simulation-based models (R2 = 0.07 and MSE = 0.49) alone. Overall map accuracy was also highest for maps created with the Integrated Model (63 %). We suspect that Simulation Model performance would greatly improve with higher quality and more accurate spatial input data. Results of this study indicate the potential benefit of combining satellite image-based methods with a fire effects simulation model to create improved burn severity maps.
Low density lipoprotein receptor up-regulation

Cholesterol homeostasis in animal cells is attained by balancing extracellular cholesterol uptake through low density lipoprotein receptors (LDLr) with de novo intracellular cholesterol biosynthesis. Maintaining appropriate cholesterol levels is critical for health as high levels can lead to atherosclerosis. Individuals with high cholesterol levels are currently treated with HMG-CoA reductase inhibitors that prevent cholesterol biosynthesis and increase production of LDLr, allowing increased uptake of cholesterol from plasma. However, direct up-regulation of LDLr synthesis would lead to the lowering of LDL cholesterol and could provide an alternative treatment for hypercholesterolaemia and provide additional benefit for those not adequately treated by statins. This article reviews compounds that increase LDLr activity by mechanisms that are postulated to have a direct effect at stimulating LDLr gene expression and not secondary effects as a consequence of inhibiting cholesterol biosynthesis. The mechanism...
Inhibition of acyl-coenzyme A:cholesterol acyltransferase 2 (ACAT2) prevents dietary cholesterol-associated steatosis by enhancing hepatic triglyceride mobilization.

Acyl-CoA:cholesterol O-acyl transferase 2 (ACAT2) promotes cholesterol absorption by the intestine and the secretion of cholesteryl ester-enriched very low density lipoproteins by the liver. Paradoxically, mice lacking ACAT2 also exhibit mild hypertriglyceridemia. The present study addresses the unexpected role of ACAT2 in regulation of hepatic triglyceride (TG) metabolism. Mouse models of either complete genetic deficiency or pharmacological inhibition of ACAT2 were fed low fat diets containing various amounts of cholesterol to induce hepatic steatosis. Mice genetically lacking ACAT2 in both the intestine and the liver were dramatically protected against hepatic neutral lipid (TG and cholesteryl ester) accumulation, with the greatest differences occurring in situations where dietary cholesterol was elevated. Further studies demonstrated that liver-specific depletion of ACAT2 with antisense oligonucleotides prevents dietary cholesterol-associated hepatic steatosis both in an inbred mouse model of non-alcoholic fatty liver disease (SJL/J) and in a humanized hyperlipidemic mouse model (LDLr−/−, apoB100/100). All mouse models of diminished ACAT2 function showed lowered hepatic triglyceride concentrations and higher plasma triglycerides secondary to increased hepatic secretion of TG into nascent very low density lipoproteins. This work demonstrates that inhibition of hepatic ACAT2 can prevent dietary cholesterol-driven hepatic steatosis in mice. These data provide the first evidence to suggest that ACAT2-specific inhibitors may hold unexpected therapeutic potential to treat both atherosclerosis and non-alcoholic fatty liver disease.
Aligned Sub-10-nm Block Copolymer Patterns Templated by Post Arrays

Self-assembly of block copolymer films can generate useful periodic nanopatterns, but the self-assembly needs to be templated to impose long-range order and to control pattern registration with other substrate features. We demonstrate here the fabrication of aligned sub-10-nm line width patterns with a controlled orientation by using lithographically formed post arrays as templates for a 16 kg/mol poly(styrene-block-dimethylsiloxane) (PS-b-PDMS) diblock copolymer. The in-plane orientation of the block copolymer cylinders was controlled by varying the spacing and geometry of the posts, and the results were modeled using 3D self-consistent field theory. This work illustrates how arrays of narrow lines with specific in-plane orientation can be produced, and how the post height and diameter affect the self-assembly.
The Influence of Perceived Social Norms on College Students' Intention to Vote

This research investigated the impact of perceived social norms about voting on college students' intention to vote. College students were asked about their perceptions of the frequency of others' voting (descriptive norms) and the importance of voting to others (injunctive norms), as well as their own intention to vote in an upcoming election. Several weeks later, students were randomly assigned to conditions where the information about the percentage of college students who voted in the last election was manipulated. Above and beyond the influence of typical predictors of voting behavior, perceived social norms about voting were found to be a significant predictor of intention to vote. Perceived importance and frequency of voting to close friends and family were consistent predictors of intention to vote. Similarity to other students moderated the relationship between descriptive and injunctive norms of student voting and intention to vote. Giving students information about the prevalence of college stu...
New Horizons for engineers

Now, as never before, the opportunity for professional success awaits every engineer who has the imagination and initiative to take advantage of it. In today's complex industrial society there is a dual demand for his talents, either as a creative, individual engineer, or as a manager of engineering work and the business enterprise as a whole.
Surface diffusion of hydrogen atoms on Cu(111) studied by optical diffraction from hydrogen density patterns formed on removable templates of xenon monolayers

We formed grating-like patterns of hydrogen adatom density on Cu(111) by using complementary patterns of xenon adatom density as the template. The template was pre-formed by laser-induced thermal desorption of a Xe monolayer on Cu(111) using the interference pattern of two coherent laser pulses. By following the evolution of hydrogen density gratings on Cu(111) from 153 to 183 K with linear optical diffraction, we found that the diffusion of hydrogen atoms on Cu(111) in this temperature range is the classical over-barrier hopping characterized by an activation energy barrier Ediff = 6.4 Kcal/mol (or 279 meV) and a pre-exponential factor D0 = 2.0 × 10−3 cm2/s. Based on the potential model proposed by Basdescu and coworkers for hydrogen on Ni(111), the WKB tunneling coefficient between the first vibrational excited states of a hydrogen adatom on Cu(111) is expected to be at least one order of magnitude smaller than that on Ni(111), indicating that the classical over-barrier hopping of hydrogen atoms could directly cross over to under-barrier tunneling between ground states on Cu(111).
Prediction of constant amplitude fatigue lives of precracked specimens from accelerated fatigue data

Abstract The feasibility of using an accelerated fatigue test programme to predict constant amplitude fatigue lives of precracked specimens was examined. An analytical basis for the fracture mechanics approach was developed by modifying earlier work that had been applied to unnotched specimens. A load programme involving a linearly increasing load with cycle number was used for the accelerated tests. The predicted curves from the accelerated test data were found to provide a good fit for the constant amplitude results in 2024-T3 and 7075-T6 aluminium alloys. These results indicate that the accelerated test data can be effectively employed to predict constant amplitude fatigue lives, while also providing a considerable reduction in testing time.
Studies on the mechanism of the dopamine-mediated inhibition of prolactin secretion.

A study of the in vitro effect of dopamine on the release of newly synthesized prolactin is reported. Pituitary glands of female rats were incubated with 4,5-3H-leucine and the radioactive prolactin present in the pituitary gland and that released into the incubation medium were measured. Incubation with 5 × l 10–7M dopamine caused an 85% decrease in prolactin release. Prior injection of the rats with perphenazine or haloperidol rendered the pituitary gland refractory to the in vitro inhibitory effect of dopamine. Although in vitro perphenazine and haloperidol had little or no effect on release of prolactin, 5 × 10–9M of these drugs directly blocked the in vitro action of dopamine on prolactin release. Phentolamine, an α-blocking agent, was partially able to block the inhibitory effect, of dopamine. Propranolol, however, was not effective. Apomorphine, an agent known to mimic the effects of dopamine, caused a significant decrease in the amount of radioactive and radioimmunoassayable prolactin released int...
How Can We Help Our K-12 Teachers?: Using a Recommender to Make Personalized Book Suggestions

K-12 teachers, especially the ones who teach reading and literacy, are expected to guide their students to read in order to learn. Teachers can promote good reading habits among K-12 readers by offering books that match their interests. Unfortunately, finding the right book for each individual or group of students is not an easy task due to the huge volume of books available these days that cover a diversity of topics at varied reading levels. To address this problem, we have developed BReT, a book recommender for K-12 teachers. BReT adopts a multi-dimensional strategy to suggest books that simultaneously match the interests, preferences, and reading abilities of K-12 students based on the content, topics, literary elements, and grade levels specified by a teacher. BReT is novel, since it recommends books to K-12 teachers tailored to their individual students or groups of students, either for pleasure reading or fulfilling their current instructional activities. Unlike existing book-searching tools currently being used by teachers, which adopt a "one-size-fits-all" strategy, BReT offers personalized suggestions. Conducted empirical studies using Mechanical Turk have verified the effectiveness of BReT in making book recommendations.
Numerical analysis of the effects of local hydrodynamics on mass transfer in heterogeneous porous media

Many engineering problems require the estimation of mass transfer coefficients in porous materials. In heterogeneous materials or in cases where mass transfer sites are not spatially uniform, empirical equations for mass transfer coefficients vary widely, and the origin of these differences is not well understood. In this article, we use a stochastic algorithm to model mass transfer from single particles in a two-dimensional heterogeneous packed bed. The computed mass transfer coefficients are used to generate a distribution of local Peclet numbers in the bed. Detailed hydrodynamics are then used to interpret variations in the local Peclet number. The results show clear relationships between pore structure, streamline patterns, and mass transfer rates.
Controversies in the management of stage III non-small-cell lung cancer

Lung cancer remains the leading cause of death in the USA and is the most common cancer both in incidence and in mortality globally (1.35 million deaths annually). Non-small-cell lung cancer accounts for >80% of all lung cancers [1] . About 35-45% of non-small-cell lung cancer patients present with locally advanced non-metastatic stage III disease. However, confirmed stage III disease represents a very heterogeneous group ranging from borderline surgical candidate with minimal mediastinal involvement to bulky mediastinal nodes or contralateral nodal involvement with significant controversy regarding optimal management in these various situations. This article specifically addresses the role of surgery, radiotherapy and chemotherapy in multimodal approach to treat stage III patients with N2/N3 involvement and controversies surrounding these recommendations.
Factors Affecting the Processing of Intensity in School-Aged Children

Purpose Thresholds of school-aged children are elevated relative to those of adults for intensity discrimination and amplitude modulation (AM) detection. It is unclear how these findings are relate...
The recrystallization of heavily-drawn

The recrystallization of 0.18 mm doped tungsten wire, swaged and drawn to a true strain of 7.7 at temperatures of <0.47Tm, was investigated by light microscopy and by transmission electron microscopy. The as-drawn structure of the wire consisted of greatly elongated, ribbon-shaped grains which had a pronounced «110” fiber texture. These contained well-developed, elongated cells with few transverse boundaries. The onset of sub-boundary and grain boundary migration, together with the formation of potassium-containing bubbles in rows oriented parallel to the drawing direction, was observed after annealing at 800°C for 1 h. At higher temperatures, the spacing and the misorientation of the longitudinal subboundaries increased, and new transverse subboundaries were formed. Both subboundary and grain boundary migration were strongly inhibited by the bubble rows, as well as by the uniformity of the deformation and the well-developed texture. At 2100°C these mechanisms produced a fine-grained, partially recrystallized structure (1.2 μm average longitudinal boundary spacing) without change in the deformation texture. At 2150°C and above, large grains of high aspect ratio, which also retained the «110» drawing texture, were formed by exaggerated grain growth. This process was initiated by a very small population of grains which had acquired the necessary size advantage during the growth of the fine-grained structure.
Scratching the Threshold: Textual Sound and Political Form in Toni Cade Bambara's The Salt Eaters

In the course of independent filmmaker Louis Massiah's 1995 inter view with African American writer, cultural worker, and political activist Toni Cade Bambara, Massiah asks Bambara how and where she learned her first political lessons. She responds by sharing her memories of coming of age amid the cultural vibrancy of Harlem, before focusing her thoughts more precisely on the lasting impact of Speakers' Corner:
Climate Change and Marine Fisheries

Abstract Increased concentrations of greenhouse gases may significantly change global climate over the next century. Atmos- pheric temperatures are expected to increase at a rate of 4°C per hundred years, a rate that exceeds the postglacial warming by more than an order of magnitude. This paper discusses the three areas where we must immediately make significant efforts to improve our knowledge if we are to stand any chance of unraveling the complex linkages between global climate change and marine fisheries production. The three areas are the prediction of oceanographic effects of climate change, the improvement of our understanding of the structure and function of the marine food chain, and the improvement of our understanding of the important social aspects of marine fisheries. We, as fisheries scientists, must develop new methodological concepts and change our way of thinking when developing public policy in anticipation of global change.
X-ray study and electrical properties of the systems SrMoxZrt(1−x)O3 and SrMoxTi(1−x)O3

Abstract An unlimited number of solid solutions are formed when either the insulator SrZrO 3 or SrTiO 3 is reacted with the conducter SrMoO 3 . The solid solutions investigated cover an electrical resistivity range from 10 −4 ohm cm to 10 3 ohm cm. Seebeck coefficient and resistivity data on several compositions of these systems are reported. BaMoO 3 and BaZrO 3 apparently do not form solid solutions.
Synthesis and Optical Properties of Red and Deep-Red Emissive Polymeric and Copolymeric BODIPY Dyes

Deep-red emissive polymeric BODIPY dyes (polymers A and B), poly(2,6-BODIPY-ethynylene)s, were prepared by palladium-catalyzed Sonogashira polymerization of 2,6-diiodo-functionalized BODIPY monomers with 2,6-diethynyl-functionalized BODIPY monomers. Poly(2,6-BODIPY-ethynylene)s emit in the deep-red region with emission spectral maxima at around 680 nm and exhibit significant red shifts (up to 163 and 172 nm) of both absorption and emission maxima compared with their initial BODIPY dyes due to significant extension of π-conjugation. Red emissive copolymeric BODIPY dyes (polymers C, D, and E) were also prepared by palladium-catalyzed Sonogashira polymerization of a diethynyl-functionalized BODIPY monomer with 9,9-bis(6′-(hexylthio)hexyl)-2,7-diiodo-9H-fluorene, 1,4-diiodo-2,5-didecyloxybenzene, and 2,5-diiodo-3-decylthiophene, respectively. Incorporation of different band gap monomer units into poly(2,6-BODIPY-ethynylene)s resulted in copolymers with a range of emission wavelengths from 641 to 664 nm. The f...
Analysis of a Crack Bridged by a Single Fiber

A two dimensional problem has been solved accurately by using continuous distributions of edge dislocations, which leads to a set of simultaneous singular integral equations.
Interactions of phytoplankton, zooplankton and microorganisms

Abstract We present evidence that there are significant interactions between heterotrophic microorganisms, doliolids and Fritillaria within intrusions of nutrient-rich Gulf Stream water stranding on the continental shelf. During the summer of 1981 cold, nutrient-rich water from below the surface of the Gulf Stream was repeatedly intruded and stranded on the continental shelf off northeastern Florida. On August 6 old, stranded Gulf Stream water depleted of nitrate occupied the lower layer on the outer shelf. The upper water was continental shelf water, older but of undefined age. On August 6 free-living bacteria were >106ml−1 everywhere at all depths, an order of magnitude greater than normal bacterial numbers on the northeastern Florida continental shelf. Over 10 days the numbers of free bacteria doubled while bacteria attached to particles increased by a factor of four. The adenylate/chlorophyll ratio showed that phytoplankton dominated the lower layers of intruded water, while the surface water became increasingly dominated by heterotrophic microorganisms (bacteria and protozoa) over 10 days. There were significant, negative correlations between bacteria and doliolids and between bacteria and Fritillaria. Regions of maximum bacterial numbers did not coincide with locations of salp swarms. The increased numbers of bacteria at all depths in a highly stratified system in which most phytoplankton are in the lower layer suggests a diverse source of bacterial growth substrates, some of which involve zooplankton as intermediaries. Production of autotrophs is more than twice that of microheterotrophs on average, but because of their differential distribution, microheterotrophs are the dominant biomass in much of the surface water and may be significant in energy flux to metazoan consumers as well as competitors for mutually useable sources of nutrition.
T7 RNA polymerase elongation complex structure and movement.

Abstract We have characterized T7RNAP elongation complexes (ECs) halted at different positions on a single template using a combination of digestion with exonuclease III, λ exonuclease, RNAse T1, and treatment with KMnO4. Our results indicate that the transcription bubble is approximately nine bases long and that the RNA:DNA hybrid is 7-8 bp in size. An additional four to six bases of RNA immediately 5′ to the hybrid interact with the RNAP, probably with a site on the N-terminal domain. When ECs with transcripts of different length were probed in the presence or absence of the incoming NTP we found that the position of the EC on the template and the RNA shifted downstream upon NTP binding. NTP binding also restricted the lateral mobility of the complex on the template. Our results indicate that, in the absence of bound NTP, the RNAP is relatively free to slide on the template around a position that usually lies one to two bases upstream of the position from which NTP binding and bond formation occur. NTP binding stabilizes the RNAP in the post-translocated position and keeps it from sliding upstream, either due directly to RNAP:NTP:template interactions, or to an isomerization which causes the fingers subdomain of the RNAP to clamp down on the downstream end of the template strand.
Development, validation, and application of an ultra-performance liquid chromatography-sector field inductively coupled plasma mass spectrometry method for simultaneous determination of six organotin compounds in human serum.

Abstract Organotin compounds (OTCs) are heavily employed by industry for a wide variety of applications, including the production of plastics and as biocides. Reports of environmental prevalence, differential toxicity between OTCs, and poorly characterized human exposure have fueled the demand for sensitive, selective speciation methods. The objective of this investigation was to develop and validate a rapid, sensitive, and selective analytical method for the simultaneous determination of a suite of organotin compounds, including butyl (mono-, di-, and tri-substituted) and phenyl (mono-, di-, and tri-substituted) species in human serum. The analytical method utilized ultra-performance liquid chromatography (UPLC) coupled with sector field inductively coupled plasma mass spectrometry (SF-ICP-MS). The small (sub-2 µm) particle size of the UPLC column stationary phase and the sensitivity of the SF-ICP-MS enabled separation and sensitive determination of the analyte suite with a runtime of approximately 3 min. Validation activities included demonstration of method linearity over the concentration range of approximately 0.250–13.661 ng mL−1, depending on the species; intraday precision of less than 21%, interday precision of less than 18%, intraday accuracy of −5.3% to 19%, and interday accuracy of −14% to 15% for all species; specificity, and matrix impact. In addition, sensitivity, and analyte stability under different storage scenarios were evaluated. Analyte stability was found to be limited for most species in freezer, refrigerator, and freeze–thaw conditions. The validated method was then applied for the determination of the OTCs in human serum samples from women participating in the Snart-Foraeldre/MiljO (Soon-Parents/Environment) Study. The concentration of each OTC ranged from below the experimental limit of quantitation to 10.929 ng tin (Sn) mL−1 serum. Speciation values were confirmed by a total Sn analysis.
A nomogram to predict the probability of passing the American Board of Internal Medicine examination

Background: Although the American Board of Internal Medicine (ABIM) certification is valued as a reflection of physicians’ experience, education, and expertise, limited methods exist to predict performance in the examination. Purpose: The objective of this study was to develop and validate a predictive tool based on variables common to all residency programs, regarding the probability of an internal medicine graduate passing the ABIM certification examination. Methods: The development cohort was obtained from the files of the Cleveland Clinic internal medicine residents who began training between 2004 and 2008. A multivariable logistic regression model was built to predict the ABIM passing rate. The model was represented as a nomogram, which was internally validated with bootstrap resamples. The external validation was done retrospectively on a cohort of residents who graduated from two other independent internal medicine residency programs between 2007 and 2011. Results: Of the 194 Cleveland Clinic graduates used for the nomogram development, 175 (90.2%) successfully passed the ABIM certification examination. The final nomogram included four predictors: In-Training Examination (ITE) scores in postgraduate year (PGY) 1, 2, and 3, and the number of months of overnight calls in the last 6 months of residency. The nomogram achieved a concordance index (CI) of 0.98 after correcting for over-fitting bias and allowed for the determination of an estimated probability of passing the ABIM exam. Of the 126 graduates from two other residency programs used for external validation, 116 (92.1%) passed the ABIM examination. The nomogram CI in the external validation cohort was 0.94, suggesting outstanding discrimination. Conclusions: A simple user-friendly predictive tool, based on readily available data, was developed to predict the probability of passing the ABIM exam for internal medicine residents. This may guide program directors’ decision-making related to program curriculum and advice given to individual residents regarding board preparation. Keywords: board examination; in-training examination; internal medicine; residents; program directors (Published: 16 October 2012) Citation: Med Educ Online 2012, 17 : 18810 - http://dx.doi.org/10.3402/meo.v17i0.18810
A critical period for functional vestibular development in zebrafish

We have determined a critical period for vestibular development in zebrafish by using a bioreactor designed by NASA to simulate microgravity for cells in culture. A critical period is defined as the briefest period of time during development when stimulus deprivation results in long lasting or permanent sensory deficits. Zebrafish eggs were collected within 3 hours of being laid and fertilized. In experiment 1, eggs were placed in the bioreactor at 3, 24, 30, 36, 48, or 72 hours postfertilization (hPF) and maintained in the bioreactor until 96 hPF. In experiment 2, eggs were placed in the bioreactor immediately after they were collected and maintained in the bioreactor until 24, 36, 48, 60, 66, 72, or 96 hPF. Beginning at 96 hPF, all larvae had their vestibulo-ocular reflexes (VOR) evaluated once each day for 5 days. Only larvae that hatched from eggs that were placed in the bioreactor before 30 hPF in experiment 1 or removed from the bioreactor later than 66 hPF in experiment 2 had VOR deficits that persisted for at least 5 days. These data suggest a critical period for vestibular development in the zebrafish that begins before 30 hPF and ends after 66 hPF. To confirm this, zebrafish eggs were placed in the bioreactor at 24 hPF and removed at 72 hPF. VORs were evaluated in these larvae once each day for 5 days beginning at 96 hPF. These larvae had VOR deficits that persisted for at least 5 days. In addition, larvae that had been maintained in the bioreactor from 24 to 66 hPF or from 30 to 72 hPF, had only temporary VOR deficits. In a final experiment, zebrafish eggs were placed in the bioreactor at 3 hPF and removed at 96 hPF but the bioreactor was turned off from 24 hPF to 72 hPF. These larvae had normal VORs when they were removed from the bioreactor at 96 hPF. Taken as a whole, these data support the idea that there is a critical period for functional maturation of the zebrafish vestibular system. The developmental period identified includes the timeframe during which the vestibular primary afferent neurons are born, innervate their central and peripheral targets, and remodel their central projections.
The Detection by Immunoassay of Antibody to Mycobacterial Antigens and Mycobacterial Antigens in Bronchoalveolar Lavage Fluid from Patients with Tuberculosis and Control Subjects

Bronchoalveolar lavage (BAL) samples from patients with pulmonary tuberculosis and from control subjects were studied using direct and inhibition enzyme-linked immunosorbent assay (ELISA) for the detection of IgC and IgA antibody to Mycobacterium tuberculosis culture filtrate and purified antigen 5 and for the detection of mycobacterial antigens. The IgC and IgA antibodies were found in the majority of samples from tuberculous patients. The IgG titers were higher than were IgA titers. Substantial nonspecificity was observed for antibodies to crude M tuberculosis culture filtrate. Antibodies to purified M tuberculosis antigen 5 were more specific. The detection of antibody in BAL did not offer advantages over previously described serodiagnostic assays. Antigen was found in some BAL samples from tuberculous patients. Greater specificity was observed with an assay based on purified antigen 5 than on crude mycobacterial culture filtrate.
Lead, zinc, and antimony contamination of the Rio Chilco-Rio Tupiza drainage system, Southern Bolivia

An intense, but localized rainfall event in February 2003, led to the severe erosion and failure of a tailings disposal impoundment at the Abarόa Antimony Mine in southern Bolivia. The failure released approximately 5,500 m3 of contaminated tailings into the Rio Chilco-Rio Tupiza drainage system. The impacts of the event on sediment quality are examined and compared to contamination resulting from historic mining operations in the headwaters of the basin. Of primary concern are contaminated floodplain soils located along downstream reaches of the Rio Tupiza which were found to contain lead (Pb), zinc (Zn), and antimony (Sb) concentrations that locally exceed Canadian, German, and Dutch guidelines for agricultural use. Spatial patterns in sediment-borne trace metal concentrations, combined with Pb isotopic data, indicate that Pb, Zn, and Sb are derived from three tributary basins draining the Abarόa, Chilcobija, and Tatasi-Portugalete mining districts. Downstream of each tributary, geographical patterns in trace metal concentrations reflect local geomorphic changes throughout the drainage system. Trace metal concentrations within the Rio Chilco decrease rapidly downstream as a result of dilution by uncontaminated sediments and storage of metal enriched particles (e.g., sulfide minerals) in the channel bed as a result of ongoing aggradation. Storage in the floodplains is limited. These processes significantly reduced the dispersal and, thus, the relative environmental affects of tailings eroded from the Abarόa Mine during the 2003 flood. In contrast, storage of Pb, Zn, and Sb in floodplains along the Rio Tupiza is significant, the majority of which is derived from historic mining operations, particularly mining within the Tatasi-Portugalete district.
RNA-dependent protein kinase PKR and the Z-DNA binding orthologue PKZ differ in their capacity to mediate initiation factor eIF2α-dependent inhibition of protein synthesis and virus-induced stress granule formation

Protein kinase R (PKR), a regulator of translation in mammalian cells, possesses two ds-RNA binding domains responsible for kinase activation. Protein kinase Z (PKZ), a PKR-like kinase present in fish, possesses two Z-DNA binding domains. A complementation strategy with cells stably deficient in PKR was used to compare the functions of PKR and PKZ. We found reporter expression was inhibited by wildtype (WT) PKR but not by either catalytic (K296R) or RNA-binding (K64E) mutants. PKZ, like PKR, more potently inhibited 5' cap-dependent compared to IRES-dependent reporter expression. However, in contrast to PKR-expressing cells, phosphorylation of initiation factor eIF2α was not detectably increased in PKZ-expressing cells. Furthermore, virus-induced stress granule formation was observed in PKR-deficient cells complemented with WT PKR but not K296R mutant PKR or WT PKZ. These results suggest that PKR and PKZ function by distinguishable mechanisms to modulate host responses including protein synthesis inhibition and stress granule formation.
Low-Loss Flex Circuit Interconnect: Development of Reduced Insertion-Loss Flexible Packaging

Developing trends within the Industrial, Consumer Electronics and Aerospace & Defense arenas have increased the demand for high-speed, high-density flexible printed circuit solutions. The goal of this paper is to describe the loss contributors within conventional flexible printed circuit constructs and how their content can be reduced to improve insertion loss and reduce attenuation. Reduction (or eventual removal) of conventional bonding film adhesive and potential future changes to existing dielectric and/or adhesive materials are considered to reach desired performance targets. Based on simulation results and laboratory measurements, this paper will describe significant loss improvements to conventional flex cross sections and outline plans for future improvements. Moreover, we will describe why this research may be of value to the signal integrity (SI) engineer working within a cost-sensitive and performance oriented application. Finally, we will discuss what new applications are enabled through the reduction of lossy conventional flexible circuit cross-sections cannot provide loss characteristics required by high-speed applications with interconnect distances of more than a few inches. Therefore, more costly bundled solutions, such as "ribbonized" coax or fiber optics are commonly employed to meet electrical requirements of high-speed applications requiring mechanical flexibility. The goal of this paper is to describe the loss contributors within conventional flexible printed circuit constructs and how their content can be reduced to improve insertion loss and reduce attenuation. Reduction (or eventual removal) of conventional bonding film adhesive and potential future changes to existing dielectric and/or adhesive materials are considered to reach desired performance targets. Based on simulation results and laboratory measurements, this paper will describe significant loss improvements to conventional flex cross sections and outline plans for future improvements. Moreover, we will describe why this research may be of value to the Signal Integrity (SI) engineer working within a cost-sensitive and performance oriented application. Finally, we will discuss what new applications are enabled through the reduction of lossy conventional flexible circuit cross-section dielectric materials.
Modulation of gene expression in the preimplantation mouse embryo by TGF‐α and TGF‐β

The effect of growth factors on regulating gene expression in the preimplantation mouse embryo was examined, since results of previous experiments revealed a stimulatory effect of exogenously-added growth factors on preimplantation development in vitro. Treatment of early cavitating blastocysts with either 250 pM TGF-alpha or TGF-beta results in changes in the pattern of total protein synthesis as assessed by high-resolution two-dimensional gel electrophoresis. In some cases, the synthesis of a particular polypeptide is either up- or downregulated by each growth factor, whereas in other instances the synthesis of a polypeptide is modulated by one but not the other growth factor. Use of the mRNA differential display method permitted the identification of genes whose expression is either up- or downregulated by these growth factors. Treatment of mouse blastocysts with either TGF-alpha or TGF-beta results in the increased expression of the b subunit of the F0ATPase. TGF-beta also stimulates the expression of the DNA polymerase alpha. TGF-alpha treatment results in the increase in expression of a gene homologous to the human HEPG2 cDNA, as well as in a decrease in expression of fibronectin.
Epitaxial Growth of InGaAs on MgAl2O4 Spinel for One-Sun Photovoltaics

A1. Planar defects A1. Substrates A3. Molecular beam epitaxy B2. Semiconducting III-V materials B3. Solar cells abstract We demonstrate coincident-site lattice-matched growth of InGaAs layers on (001) MgAl2O4 spinel substrates, using a 451 rotation between the lattices, by molecular beam epitaxy. This is the first step towards easily removable multijunction solar cells with inert, reusable substrates. High-resolution cross-sectional transmission electron microscopy (TEM) measurements indicate that microtwins originate at the InGaAs/spinel interface, but tend to annihilate leaving the upper parts of layers relatively twin-free . Plan-view TEM indicates a high density of threading dislocations. InGaAs layers grown at elevated temperatures show improved transport properties, with majority-carrier mobilities approaching typical values for homoepitaxial GaAs on GaAs substrates. Simple p-i-n junctions show photovoltaic efficiencies above 1%.
SIMILARITY SOLUTIONS FOR STEADY LAMINAR CONVECTION ALONG HEATED PLATES WITH VARIABLE OBLIQUE SUCTION: NEWTONIAN AND DARCIAN FLUID FLOW

The similarity solution ansatz that Burde applied to adiabatic boundary-layer flow over flat plates and slender bodies of revolution is employed here to investigate mixed convection flow adjacent to heated inclined flat plates. Both Newtonian and Darcian fluids are considered under the assumption that they obey the Boussinesq approximation. New results fall into two distinct categories for heated plates with oblique wall suction. Class I problems correspond to radial source/sink flows interior to a wedge and class II problems pertain to uniform rectilinear flow over flat plates. Except in special cases, solutions of the class I equations must be obtained numerically while all class II equations possess explicit analytical solutions encompassing natural, mixed, or forced convection depending on the magnitude of the free-stream velocity. Numerical integration of prototype class I problems reveals single or dual solutions for radial inflow and an infinity of oscillatory solutions for radial outflow. The similarity solutions reported here describe flows with continuous distributions of temperature and suction angle along the plate, and in some cases the variation of the temperature, suction strength, or suction angle may be chosen freely.
Who Matches? Propensity Scores and Bias in the Causal Eﬀects of Education on Participation

Matching is increasingly being used in political science to reduce selection bias in casual estimation. In a recent study, Cindy Kam and Carl Palmer employ propensity score matching to assess the decades-long consensus that college attendance increases political participation. The authors find no effect, upending a major pillar in social science. While we agree that selection is a serious concern, we argue it is so substantial in the choice to attend college that good matches may be very difficult to obtain. In this situation, propensity score matching may actually increase bias. We match on nearly 800,000 propensity scores and use genetic matching to recover better matches with lower covariate "imbalances". We find even modest improvements reverses the null finding, however, no matching approach yields unbiased estimates. Ultimately, we show that 'balance' in the covariates and robustness to sensitivity diagnostics should guide the matching enterprise.
ACE-inhibitory activity of tilapia protein hydrolysates

Abstract Fish processing wastes can be used for preparing bioactive peptides with various functionalities. Our objective was to evaluate the in vitro angiotensin converting enzyme (ACE) inhibitory activity of tilapia protein hydrolysates and its corresponding fractionates. Tilapia protein was alkali-solubilised at pH 11.0 and recovered at pH 5.5 to obtain a stable substrate. This substrate was hydrolysed using two enzymes, Cryotin-F or Flavourzyme, to 7.5% and 25% degree of hydrolysis (DH). The hydrolysates were ultra-filtered into three fractions: >30 kDa fraction, 10–30 kDa fraction, and
Remark on Algorithm 702—the updated truncated Newton minimization package

A truncated Newton minimization package, TNPACK, was described in ACM Transactions on Mathematical Software 14, 1 (Mar. 1992), pp.46–111. Modifications to enhance performance, especially for large-scale minimization of molecular potential functions, are described here. They involve three program segments of TNPACK: negative curvature test, modified Cholesky factorization, and line-search stopping rule.
The dual function of the A-V junction

Abstract The various electrocardiographic syndromes that develop as a consequence of abnormal dissociation of the two functions of the A-V junction can be summarized as follows (Table II): Acceleration of impulse formation in one or two pacemakers without any block in the A-V junction leads either to junctional rhythm with retrograde activation of the atria, or to isorhythmic A-V dissociation; when associated with retrograde block, the dissociation is incomplete with ventricular captures; when first- or second-degree antegrade block develops in addition, the captures tend to disappear and the A-V dissociation to become complete. An exit block of the junctional impulses may slow the manifest ventricular rate during the dissociation, and finally, an additional protective entrance block around the junctional pacemaker results in junctional parasystole. On the other hand, depression of junctional impulse formation without A-V block is one of the mechanisms responsible for the tachycardia-bradycardia syndrome. The basis of such a functional separation of the two properties of A-V junctional tissues appears to be a difference in structure and electrophysiologic behavior of cell elements that constitute the A-V junction.
Insulin‐like Growth Factor‐I and IGF‐I Receptors in Diabetic Patients with Neuropathy

Since a number of animal studies have shown that insulin-like growth I (IGF-I) stimulates nerve regeneration, the aim of our study was to evaluate the possible relationship between IGF-I and IGF-I receptors in diabetic patients with peripheral neuropathy. One hundred and four patients with Type 2 diabetes (57 with peripheral neuropathy and 47 non-neuropathic) were studied. Controls were 17 non-diabetic persons. After an overnight fast, blood was taken for IGF-I, IGF-I receptors, glucose, HbA1, C-peptide, and insulin. The neuropathy study group had significantly lower levels of IGF-I:144.5 ng ml-1 (57.5-363.0, 95% confidence limits) compared to controls: 186.2 ng ml-1 (93.3-371.5), p < 0.01, and to diabetic patients without neuropathy: 173.7 ng ml-1 (83.1-363.0), p < 0.01. The study group also had a lower number of IGF-I receptors per red cell: 22.9 x 10(3) (13.08-38.01) vs control subjects: 28.1 x 10(3) (18.62-42.65), p < 0.01, and non-neuropathic diabetic patients: 26.3 x 10(3) (16.59-41.68), p < 0.01. In diabetic subjects there was a positive correlation (r = 0.20, p < 0.05) between IGF-I and HbA1, while in the neuropathy group there was a negative correlation between the score for nerve dysfunction with the IGF-I (r = -0.39, p < 0.01) and with IGF-I receptors (r = -0.34, p < 0.01). We conclude that in diabetic patients with peripheral neuropathy there are abnormalities of IGF-I and IGF-I receptors which may contribute to impaired neuronal regeneration.