cssi/SciSciGPT-SciSciNet huggingface dataset:
Interlaminar Stresses around Circular Cutouts in Composite Plates under Tension

1~5 From these results, the static failure strengths are obtained with good quantitative prediction compared to experiments. Delamination at free edges is another failure mode of laminated composites, especially under fatigue loadings. Extensive delamination at free edges is reported on static strength as well as fatigue strength, with and without notches.6"10 Hence, the determination of interlaminar shear stresses and the normal or "peel" stress is a current research topic. However, all the previous studies are restricted to straight boundaries11"27 except for finite element solutions in Refs. 14 and 28-30. There is no analytical closed-form solution available to predict interlaminar stresses for curvilinear boundaries. Therefore, the present paper attempts to study the interlaminar stresses at a circular cutout in an "infinite" composite laminate under uniform tensile load. The boundary-layer theory for composite laminates in Ref. 20 is extended here to the formulation of polar coordinates, and the title problem is investigated for the case of orthotropic composite plates. The laminate considered here is under inplane loading symmetric about the midplane. The construction of the laminate is also midplane symmetric so that there is no stretching/bending coupling of the plate due to external load. The force resultants around the hole of an orthotropic or anisotropic plate are given by Refs. 31 and 32. The radial and shear force resultants at the edge of the hole are zero. From the plane stress solution, the strains at the edge of the hole can be calculated by the force resultant-strain relation. Due to the compatibility of deformation, the strains of individual layers are the same as the laminate. Therefore, the stresses of each layer may then be computed from the layer stress-strain law. However, the computed radial and shear stresses of each layer along the contour of the hole are in general not zero. Because there exists a three-dimensio nal state of stresses at the free edge of each layer where the plane stress solution cannot predict. The region of the plate adjacent to and including the edge, where the plane stress solution may not be adequate, is called the boundary layer. To obtain the governing equations in this
Recurrent coagulopathy after rattlesnake bite requiring continuous intravenous dosing of antivenom

Context. Snakebite envenomation is common and may result in systemic coagulopathy. Antivenom can correct resulting laboratory abnormalities; however, despite antivenom use, coagulopathy may recur, persist, or result in death after a latency period. Case Details. A 50-year-old previously healthy man presented to the emergency department after a rattlesnake bite to his right upper extremity. His presentation was complicated by significant glossal and oropharyngeal edema requiring emergent cricothyrotomy. His clinical course rapidly improved with the administration of snake antivenom (FabAV); the oropharyngeal and upper extremity edema resolved within several days. However, over the subsequent two weeks, he continued to have refractory coagulopathy requiring multiple units of antivenom. The coagulopathy finally resolved after starting a continuous antivenom infusion. Discussion. Envenomation may result in latent venom release from soft tissue depots that can last for two weeks. This case report illustrates the importance of close hemodynamic and laboratory monitoring after snakebites and describes the administration of continuous antivenom infusion, instead of multidose bolus, to neutralize latent venom release and correct residual coagulopathy.
The mortality risk of expectant management compared with delivery stratified by gestational age and race and ethnicity

Objective The objective of the study was to compare the mortality risk of expectant management with the risk of delivery at each week of term pregnancy in 4 racial/ethnic groups. Study Design This was a retrospective cohort study of all nonanomalous, term deliveries in California from 1997 to 2006 among white, black, Hispanic, and Asian women. In each racial/ethnic group, we compared the risk of infant death at each week with a composite risk representing the mortality risk of 1 week of expectant management. Results The risk of stillbirth and infant death is highest in black women (stillbirth risk: 18.0 per 10,000, infant death: 24.4 per 10,000, compared with 9.4 per 10,000 and 10.8 per 10,000 in white women, respectively; P Conclusion The mortality risk of expectant management exceeds the risk of delivery at 39 weeks in all racial/ethnic groups, despite variation in absolute risks.
A matrix convexity approach to some celebrated quantum inequalities

Abstract Some of the important inequalities associated with quantum entropy are immediate algebraic consequences of the Hansen–Pedersen–Jensen inequalities. A general argument is given using matrix perspectives of operator convex functions. A matrix analogue of Marechal's extended perspectives provides additional inequalities, including a p + q ≤ 1 result of Lieb.
Estimating the cost of extracting cereal protein with ethanol

Abstract Most cereals contain prolamine-rich proteins, which are water insoluble, but soluble in alcohol solutions. These proteins could be used as constituents of temporary, environmentally stable coatings and films. It may be economically feasible to separate these proteins as part of a starch to ethanol process, if the alcohol solvent separation and recovery cost are low enough. Estimates of separated protein product cost can be made using a separation process simulation developed for maize. A general cost model was formulated as the sum of two major energy-consuming units, distillation and product drying, and three other overall cost fractions based on two mass flow ratios, namely, the solvent to cereal feed and the product to feed. Model coefficients were calculated from fits of the simulation cost predictions for zein extraction.
DPP4 Inhibitors : a New Approach in Diabètes Treatment

The role of dipeptidyl peptidase-IV (DPP4) as both a regulatory enzyme and a signalling factor has been evaluated and described in many studies. DPP4 inhibition results in increased blood concentration of the incretin hormones glucagon-like peptide-1 (GLP-1) and gastric inhibitory polypeptide (GIP). This causes an increase in glucose-dependent stimulation of insulin secretion, resulting in a lowering of blood glucose levels. Recent studies have shown that DPP4 inhibitors can induce a significant reduction in glycosylated haemoglobin (HbA1c) levels, either as monotherapy or as a combination with other antidiabetic agents. Research has also demonstrated that DPP4 inhibitors portray a very low risk of hypoglycaemia development. This review article focuses on the two leading agents of this category (sitagliptin and vildagliptin), providing an overview of their function along with the latest data regarding their clinical efficacy as antidiabetic agents.
Knowledge, interests and educational needs of adults diagnosed with cystic fibrosis after age 18.

Abstract Background: Little is known about the knowledge, interests, or educational needs of those diagnosed with cystic fibrosis (CF) as adults or the extent to which they find available information helpful. The purpose of this inquiry was to address these gaps. Methods: A mailed survey, completed by an international sample ( N =130) recruited through internet sites and CF Centers, collected quantitative and qualitative data to address five research questions. A response rate of 74.3% was achieved. Results: Most participants (67.4%) said they knew little or nothing about CF at diagnosis. Of the 71.5% who indicated they received patient education, 26.9% felt they were given ‘too little'. At diagnosis, most wanted disease-related information about CF. Over time they expressed interest in topics related to quality-of-life, such as CF research efforts, alternative medicine and employment issues. Three-fourths (75.4%) were active information seekers, but 60.2% were less than satisfied with what they found. Qualitative responses indicated participants did not ‘see themselves' in available materials, which many described as ‘depressing'. Conclusions: Medical caregivers must be aware of and respond to the unique educational interests and needs of their adult-diagnosed patients. Additional research is recommended to better understand how patient education benefits these adults.
Quasilinear theory of ion-cyclotron-resonance heating of plasmas and associated longitudinal cooling

It is shown from a quasilinear theory that an initially isotropic magnetized plasma will be forced into an anisotropic state in ion-cyclotron-resonance heating. Strong heating of the perpendicular ion temperature and strong cooling of the longitudinal temperature should occur simultaneously. The maximum temperature ratio predicted by the quasilinear theory is in exact agreement with that predicted from the basic thermodynamic arguments by Busnardo-Neto, Dawson, Kamimura, and Lin. Heating by fast hydromagnetic waves is also examined. (AIP)
Effects of thermal treatment and dc bias on dielectric aging in the plzt 9.5:65:35 relaxor ferroelectric ceramic

Abstract The dielectric aging effects after thermal treatments and under DC bias were studied and delineated for Lead Lanthanum Zirconate Titanate (PLZT 9.5:65:35) relaxor ceramic. Under room temperature aging, dielectric constant and loss tangent as a function of aging time obey a power law (K = Kot “) and the power index (n) follows the logarithmic law with measured frequency. The aging rate was enhanced by the quenching prior to the aging process. The DC bias reduced the aging rate especially under high measured frequencies. During aging, the Cole-Cole plot shrinks with aging time in such a way that the average relaxation time constant decreases and the distribution of relaxation time constant become narrow with aging time. All the effects are correlated and modeled with the characteristics of relaxor ferroelectrics. The aging process looks like that the polar microregions have a preferred orientation corresponding to the deepest minimum in energy and its contribution to the total permittivity will dec...
A kinetic model of CD4+ lymphocytes with the human immunodeficiency virus (HIV).

This report describes a kinetic model of in vitro cytopathology involving interactions of human immunodeficiency virus (HIV) with CD4+ helper T lymphocytes. The model uses nonlinearly coupled, ordinary differential equations to simulate the dynamics of infected and uninfected cells and free virions. It is assumed that resting cells are more readily infected than activated cells, but once infected, only activated cells produce more virus. Resting cells can be activated by some appropriate stimulus (e.g. phytohemagglutinin, soluble antigen). The model predicts that the initial inoculum of virus is taken up by resting cells and without stimulation the system comes to a steady state of two populations, namely infected and uninfected cells. Stimulation of this system produces two additional populations, namely infected and uninfected activated cells which, along with the previous populations, exhibit cyclic behavior of growth, viral expression/release, and death. Additional stimuli enhance or diminish the cyclic behavior depending upon their occurrence in time. These simulations suggest a similar dynamics in human HIV infection and may explain a major factor responsible for the widely varying depletion rate of (CD4+) helper T cells in AIDS patients.
Importance of microplasticity in the fracture of silicon

Notched, wedge-shaped silicon crystals were subjected to tensile deformation and canti-lever bending in the temperature range 500 to 800°C. The microplastic zones and elastic strain distribution ahead of the propagating crack were disclosed by combining various sensitive X-ray diffraction and electron microscopy methods. The importance of the mi-croplastic zones for the notch-brittle sensitivity was shown. The changes in fracture stress with deformation temperature were attributed to the ability of the strain-hardened plastic zones to constrain the residual elastic strains. Upon annealing, the elastic strains were eliminated by the sweeping of dislocation loops emanating from the boundaries of the con-straining microplastic zones.
Learning personal + social latent factor model for social recommendation

Social recommendation, which aims to systematically leverage the social relationships between users as well as their past behaviors for automatic recommendation, attract much attention recently. The belief is that users linked with each other in social networks tend to share certain common interests or have similar tastes (homophily principle); such similarity is expected to help improve the recommendation accuracy and quality. There have been a few studies on social recommendations; however, they almost completely ignored the heterogeneity and diversity of the social relationship.In this paper, we develop a joint personal and social latent factor (PSLF) model for social recommendation. Specifically, it combines the state-of-the-art collaborative filtering and the social network modeling approaches for social recommendation. Especially, the PSLF extracts the social factor vectors for each user based on the state-of-the-art mixture membership stochastic blockmodel, which can explicitly express the varieties of the social relationship. To optimize the PSLF model, we develop a scalable expectation-maximization (EM) algorithm, which utilizes a novel approximate mean-field technique for fast expectation computation. We compare our approach with the latest social recommendation approaches on two real datasets, Flixter and Douban (both with large social networks). With similar training cost, our approach has shown a significant improvement in terms of prediction accuracy criteria over the existing approaches.
High strain plane-strain deformation of 70-30 brass in a channel die

Abstract Parallel-piped samples of 90 and 4 μm grain size 70-30 brass have been deformed in plane-strain in a channel die up to a true strain of 2.3. Optical and electron metallography and X-ray diffraction have been used to determine the development of microstructure and texture with strain. The stress-strain data have been obtained by measuring the specimen dimensions and the load after each increment of 0.1 true strain. At low strains 70-30 brass deforms mainly by slip and at slightly higher strains by a combination of slip and twinning. At medium strains shear bands form. The average angle which they make with the compression plane and also their density increases with strain. The strain at which they form and their angle is different for the two grain sizes examined. The stress-strain curves show three distinct hardening stages. At low and high strains the rate of work hardening is high, while at medium strains the rate is low. Shear bands form when the rate of work hardening is low but positive and continue to form at high strains under a high rate of work hardening.
Inhibition of (Na+,K+)-ATPase by fluoride: Evidence for a membrane adaptation to ethanol

Fluoride ions inhibit several membrane enzymes in a manner that is dependent on membrane fluidity. Inhibition of (Na+, K+)-ATPase by fluoride ions may be a model for membrane effects on (Na+, K+)-ATPase. Therefore, we have examined properties of fluoride inhibition relative to interactions with ethanol and to ligands that alter sensitivity of (Na+, K+)-ATPase to ethanol. Fluoride ion reduced the K0.5 and Hill coefficient for K+ activation of p-nitrophenylphosphatase. Ethanol decreased the Hill coefficient and apparent affinity for inhibition of phosphatase activity by fluoride ion while dimethylsulfoxide had the opposite effects. Chronic ethanol treatment in vivo, which produced behavioral tolerance, had effects on fluoride inhibition opposite to those of ethanol in vitro. Inhibition by fluoride therefore may provide a useful marker for physiologic or pharmacologic conditions that alter regulation of (Na+, K+)-ATPase by membrane properties.
Structural changes and labor productivity slowdown in the Euro Area

El bajo crecimiento de la productividad ha estado presente en la zona del euro desde mediados de la decada de los noventa. Esto es particularmente llamativo al contractual con las importantes ganancias en productividad observadas en los Estados Unidos durante el mismo periodo. En el presente trabajo se muestra que la desaceleracion de la productividad laboral en la zona del euro fue causada por cambios estructurales en la formacion de salarios, que afectaron el precio relativo del trabajo, incrementaron la intensidad del trabajo en el crecimiento y redujeron la profundizacion del capital. Los choques tecnologicos jugaron un papel menor explorando esta desaceleracion. Este puede ser un efecto economico general que puede estar presente en otros paises que han tratado de reduccion sus tasas de desempleo. Los cambios tecnologicos desempenaron un papel menor en la explicacion de dicha desaceleracion.
Fabrication and wear resistance of Al–Cu–Fe quasicrystal-epoxy composite materials

Abstract Wear resistant polymer composites are prepared using a novel filler material, Al–Cu–Fe quasicrystals (QC). Novolac epoxy filled with Al–Cu–Fe quasicrystalline powder are evaluated by pin-on-disk testing using a 52100 steel counterface. Epoxy samples filled with aluminum, copper, iron, aluminum oxide, and silicon carbide are tested for comparison. The use of Al–Cu–Fe QC powder, as a filler in epoxy, maximizes the composite wear resistance while minimizing abrasion of the 52100 steel counterface. Wear mechanisms of the Al–Cu–Fe composites were characterized by scanning electron microscopy and X-ray photoelectron spectroscopy. The fabrication and wear properties of these unique materials will be described.
Genetic coding and protein synthesis: Concerted evolution

Abstract This paper summarizes our views and data relative to the coevolution of the genetic code and the process of protein synthesis. The component aminoacyl transfer reactions were found to be spontaneous for the most part. However, formation of peptides from phenylalanyl-AMP-ester did not occur, and this observation raises some question as to the mechanism of peptide bond formation in the contemporary. Exploration of properties of amino acids and nucleotides show correlations between both the hydrophobicity and the hydrophilicity of amino acids and their anticodon nucleotides. Furthermore, work with thermal proteinoids shows a possible affinity of amino acids for anticodon nucleotides. We suggest, as a result of these observations, that a primitive protein synthesis system may have existed in which classes of amino acids were activated by mononucleotide triphosphates (i.e., ATP would activate all hydrophobic amino acids, UTP would activate charged hydrophilic amino acids, CTP uncharged hydrophilic amino acids and GTP those of intermediate hydrophobicity). In this model the nucleotidyl triphosphates simultaneously activate and adapt the amino acids. Subsequently, the nucleotide, carrying the amino acid, base pairs with a “messenger” RNA, organizing the amino acids for polymerization. An essential feature of the model is that the recognition step takes place before the “messenger” is present. The mononucleotides are thus envisioned as the simplest evolutionary precursors of tRNAs. Natural selection processes would have led to the evolution from 1/1 coding with mononucleotide adaptors to 3/1 coding via evolution of the tRNAs.
ACTUAL AND OPTIMAL AMOUNTS OF GENERAL EDUCATION IN OCCUPATIONAL PROGRAMS

This study determined and compared the views of community college graduates and leavers of occupational programs on the actual and optimal amounts of general education. Data were collected via mail survey from a random sample of 400 graduates and leavers. Results suggested that actual amounts of general education taken differed from the optimal amount desired. All AAS and certificate students had taken proportionately more general education than desired, in particular certificate leavers. The study identified sufficient concensus among the groups surveyed to suggest that community college administrators should reevaluate required proportions of general education in occupational programs
Tuberculous gluteal abscess without bone involvement

A cold abscess secondary to tuberculous spondylitis or osteomyelitis is a well-recognized entity. However, a soft tissue tuberculous abscess without bone involvement is rare. We present such a case.
The End of European Immigrant Servitude in the United States: An Economic Analysis of Market Collapse, 1772-1835

Europeans stopped using servitude to finance passage to America sometime in the early nineteenth century, but exactly when and why immigrant servitude disappeared is a mystery. Hypotheses abound, but no consensus has emerged nor have scholars tested hypotheses. In this study, quantitative evidence for the final sixty years of immigrant servitude establishes when and why it disappeared. Servitude did not end because of insufficient demand, legal restrictions, or declines in passage fares. It ended because superior methods of financing migration developed. Chance historical events, however, determined the exact timing of the end. In North America, organized markets for European immigrant servants flourished for two centuries. The resilience of these markets is quite remarkable. They survived the turbulent events of the seventeenth and eighteenth centuries, including frequent and severe interruptions to transatlantic trade caused by wars and depressions, competition in America from slave and native-born free labor, and the change in legal sovereignty caused by the American Revolution. During the eighteenth century, roughly one-half of the Europeans landing in British North America paid for their passage by selling contracts on their future
Relative Size of Males and Competition for Females Induces Homosexual Behavior in the Western Mosquitofish (Gambusia affinis) Under Laboratory Conditions

In an ongoing experiment, we investigated how mating behaviors of male western mosquitofish Gambusia affinis change across a range of temperatures. During behavioral trials, we observed high levels of homosexual behavior between males when in a competitive situation. We observed that when two males are in competition for matings with females, the smaller male performed significantly more homosexual acts than the larger. These results suggest that a dominance relationship develops with males in competition, where large males may dominate small males by not allowing them to copulate with the female, thereby causing an increase in same-sex mating by smaller males. Although preliminary data also indicate a possible relationship between density of males and number of homosexual copulations, we were not able to statistically analyze the relationship because these observations occurred during an ongoing experiment. In a future study, we will seek to understand underlying causes of homosexual behavior in the western mosquitofish. RESUMEN—En un experimento en curso, investigamos como el macho del guayacon mosquito (Gambusia affinis) cambia su comportamiento de apareamiento a traves de un rango de temperaturas. Durante pruebas de comportamiento en situaciones competitivas se observaron altos niveles de homosexualidad entre los machos. Observamos que cuando dos machos estuvieron en competencia para copular con hembras, el macho pequeno realizom as actos homosexuales que el macho grande. Estos resultados sugieren que una relacion de dominancia se crea cuando hay machos en competencia para apareamiento. Los machos de mayor tamano pueden dominar a los machos pequenos e impedirles aparearse con las hembras, causando aso ´ un incremento en el apareamiento del mismo sexo por machos pequenos. Aunque los datos preliminares tambien indican una posible relacion entre el numero de actos homosexuales y la densidad de machos, no pudimos analizar esta relacion estado ´sticamente porque se hicieron las observaciones durante un experimento en curso. En un futuro estudio, procuraremos entender las causas de comportamiento homosexual del guayacon mosquito.
The cost-effectiveness of a "quick-screen" program for abdominal aortic aneurysms.

Background. The incidence of abdominal aortic aneurysm (AAA) is increasing, and the prognosis of ruptured AAA remains dismal. Early diagnosis and intervention are crucial. We designed this study to determine whether selected population screening with a brief “quick-screen” ultrasound could be cost-effective. Methods. A series of 25 patients with risk factors for AAA were evaluated in a blinded fashion by a quick-screen ultrasound and a full conventional study. Times and accuracy for the 2 approaches were compared. An analysis of the cost-effectiveness of screening for AAA was then performed using a Markov model. We determined the long-term survival in quality-adjusted life years and lifetime costs for a hypothetical cohort of 70-year-old males undergoing either AAA screening or not. Our measure of outcome was the cost-effectiveness ratio (CER). Results. The average time for a quick screen was one-sixth that of a conventional study (4 vs 24 minutes). The accuracy of the quick screen was 100%. In our base-case analysis, screening for AAA was cost-effective with a CER of $11,215. Society usually is willing to pay for interventions with CER of less than $60,000 (eg, CER for coronary artery bypass grafting, $9500; breast cancer screening, $16,000). In sensitivity analysis, reducing the cost of screening from $259 (approximate Medicare reimbursement) to $40 (the quick screen) improved the CER to $6850. Moreover, screening populations with increased prevalence of AAA (eg, male with family history [18%]) further improved the CER. Conclusions. Our analysis demonstrates that ultrasound screening for AAA should be offered to all males above the age of 60. Widespread screening for AAA should be adopted and reimbursed by Medicare and other insurers. (Surgery 2002;132:399-407.)
Successive Transformations of an Established Cell Line by Polyoma Virus and SV40

Two different oncogenic viruses, polyoma and SV40, are capable of transforming mouse cell line 3T3. The properties of the transformed cells produced by the two viruses are in some ways similar, but in other ways they are specific for the infecting virus. This fact permits testing whether a cell line transformed by the one oncogenic virus is still susceptible to the transforming action of the second virus. Two different clonally isolated polyoma-transformed lines when infected with SV40 give rise to cells with properties characteristic of SV40-transformed cells. The frequency of transformation, however, is considerably reduced compared to that of the parent cell line, 3T3.
Chemical biology: Caught in the activation.

A crystal structure reveals how a protein kinase is activated by the binding of a small molecule at a pocket far from the catalytic site. This opens the door to the design of modulators of protein phosphorylation.
Efficiency and limitations of the hn-cDNA library approach for the isolation of human transcribed genes from hybrid cells.

The use of splice donor site consensus sequences as primers in cDNA synthesis (to make a cDNA library from heterogeneous RNA or unprocessed transcript—an hn-cDNA library) and the screening of such an hn-cDNA library with human repeat DNA probe in order to isolate human genes from somatic cell hybrids have been demonstrated. Here, we optimize and evaluate the efficiency and limitations of the approach. Computer analysis of genomic sequences of 22 randomly selected human genes indicated that hexamers CTTACC, CTCACC, and CCTACC were most efficient at beginning first-strand cDNA synthesis at donor splice sites of hnRNA and suggested that the procedure is efficient for priming cDNA synthesis of at least one exon from most every gene. Primer extension experiments established conditions in which the primers would initiate synthesis of cDNA starting from a perfectly matched position on the RNA template at more than 60-fold higher yield than any other product. By isolation of a clone containing exon III of the human DNA repair gene ERCC1, we indicate that the approach is capable of cloning exons from weakly expressed genes. Sequencing of clones revealed a structure of hn-cDNA clones consistent with the expectations of the cloning strategy and indicated the potential of the clones in detecting polymorphisms. Finally, we demonstrate that the expression of these hn-cDNA sequences in cells can be detected efficiently at the hnRNA level by reverse transcriptase-polymerase chain reaction (RT/PCR).
Cerebrovascular Adaptation After Unilateral Carotid Artery Ligation in the Rat: Preservation of Blood Flow and ATP During Forebrain Ischemia

To investigate long-term adaptations after unilateral carotid artery ligation, the effect of forebrain ischemia on cerebral blood flow and ATP levels was determined at various times after ligation. Unilateral carotid artery ligation was performed in male Wistar rats 0, 3, or 7 days before forebrain ischemia. Laser-Doppler blood flow was monitored bilaterally over the parietal cortex and ATP was measured in the subadjacent cortex of both hemispheres at the end of a 10-minute episode of ischemia. In the 0-day group, forebrain ischemia reduced cortical blood flow to 12% +/- 8% (mean +/- SD) of preischemic values and lowered cortical ATP to 26% +/- 35% of control levels in the ipsilateral hemisphere. Delaying the onset of forebrain ischemia for 3 days after carotid artery ligation significantly improved cortical blood flow (29% +/- 12%, P < 0.05) and ATP levels (92% +/- 11%, P < 0.05) in the ipsilateral hemisphere. Delaying forebrain ischemia for 7 days also significantly improved ipsilateral blood flow (36% +/- 11%, P < 0.05) and ATP levels (81% +/- 29%, P < 0.05) compared with the 0-day group. In the contralateral hemisphere, the reduction in blood flow and ATP levels was not significantly altered by delaying the onset of forebrain ischemia for 3 or 7 days. These results show that unilateral carotid artery ligation induces long-term vascular adaptations that improve the collateral circulation and preserve ATP levels during a subsequent episode of ischemia.
Identification of a region of Escherichia coli DnaB required for functional interaction with DnaG at the replication fork.

The fundamental activities of the replicative primosomes of Escherichia coli are provided by DnaB, the replication fork DNA helicase, and DnaG, the Okazaki fragment primase. As we have demonstrated previously, DnaG is recruited to the replication fork via a transient protein-protein interaction with DnaB. Here, using site-directed amino acid mutagenesis, we have defined the region on DnaB required for this protein-protein interaction. Mutations in this region of DnaB affect the DnaB-DnaG interaction during both general priming-directed and φX174 complementary strand DNA synthesis, as well as at replication forks reconstituted in rolling circle DNA replication reactions. The behavior of the purified mutant DnaB proteins in the various replication systems suggests that access to the DnaG binding pocket on DnaB may be restricted at the replication fork.
Teachers' implementation of a game-based biotechnology curriculum

Research in education suggests that computer games can serve as powerful learning environments, however, teachers perceive many obstacles to using games as teaching tools. In this study, we examine three science teachers' implementation and perceptions of a curriculum unit incorporating the game, Mission Biotech (MBt) and a set of supporting curriculum materials. The curriculum unit was designed to provide multiple avenues for teachers to adjust and modify materials and implementation plans based on their unique classroom goals and environments. To understand how individual teachers use, conceptualize, and reflect upon the MBt unit and its implementation, we conducted three case studies, including classroom observations and teacher interviews. Findings include many similarities among teachers including adaptation of activities to classroom norms and practices, high value placed on quality curricular resources and support, advantage of the game to provide experiences that are normally out of reach for students, and concerns about effective use of time. Unique features of different teachers revealed implications for design and professional development for game-based curricula. For example, the study revealed that teachers need support to integrate and make explicit connections between the game and supporting curriculum materials.
Geographic variability of Pinus flexilis xylem monoterpenes

Wood from 237 trees of Limber pine (Pinus flexilis) was collected in 24 localities throughout the species range and analysed by gas chromatography for monoterpenes and volatile alkanes: α-pinene, β-pinene, 3-carene and limonene were the main constituents. Fourteen other monoterpenes plus n-undecane were also found. The southwestern populations from California and adjoining areas of Nevada separated from the rest of the basis of increased amounts of α-pinene and smaller amounts of myrcene, 3-carene, limonene and β-phellandrene. This differentiation was rationalized by the separation of the two population groups by deserts during the Quaternary.
Vibrational spectrum of 1,3,5-triamino-2,4,6-trinitrobenzene

Abstract The mid-infrared (4000-400 cm −1 ) spectra in KBr matrix of the title compound (TATB) and four of its isotopic derivatives have been analysed for the purpose of vibrational assignments. The relative simplicity of the spectra, in conjunction with the various isotopic shifts, indicates that thirteen of the seventeen principal spectral features can be attributed to vibrational modes originating in the amino- and nitro-moieties; the remaining four bands to skeletal vibrations. In comparison with spectra of aniline and nitrobenzene, the assignments are consistent with predicted spectral changes due both to hydrogen-bonding and to the presence of canonically electron-withdrawing and electron-donating substituents.
The doctor-patient relationship in the home.

Exploring the dynamics of the relationship between a patient and a physician is a daunting task. The study of the nuances of interpersonal relationships in an attempt to qualitatively explain their content is an intellectually challenging and enlightening experience. In this article the author goes one step further and takes the players out of the doctor’s office to begin to understand what happens when the doctor visits the patient in his or her home. In past years, making house calls was a way of life, as much the norm as a conventional office visit.’ In many instances, the patient was a friend or family acquaintance. The implied benevolence of that visit was in part what made the doctor a revered member of society. As medical science advanced, so, too, did telecommunication and transportation systems. Speaking with the doctor on the phone or getting to his or her office for care has become easier. The most advanced medical diagnostic technology was based in doctors’ offices or hospital-based practices, and patients were willing to travel to their physicians to receive state-of-the-art care.8 In the last decade there have been major changes in the arena of health care policy and economics that have changed how medicine is practiced. In many instances, the pressure put on physicians to maximize their productivity has led to dissatisfied consumers and unhappy health care pr0~iders.l~ The time allotted for office visits has been reduced, and the opportunity for physicians to spend the extra time for a house call is a thing of the past.8 Along with the issues of time constraints and
Mining Technical Resources for Business Information

Business librarians can benefit from a deeper understanding of science and engineering resources, especially when researching technological topics, products, or industries. The authors introduce a variety of technical publications and databases useful for business research. Categories of resources described include technical encyclopedias and handbooks, periodical indexes and full-text databases, patents, technical reports, product literature, preprint and open-access repositories, conference proceedings, and dissertations. A case study based on MP3 audio technology demonstrates the types of business information that can be uncovered through a careful search of technical sources.
Efficient isolation and mapping of rad genes of the fungus Coprinus cinereus using chromosome-specific libraries

We have constructed cosmid libraries from electrophoretically separated chromosomes of the basidiomycete Coprinus cinereus. These libraries greatly facilitate the isolation of genes by complementation of mutant phenotypes and are particularly useful for map-based cloning strategies. From a library constructed from two co-migrating C.cinereus chromosomes, we isolated a clone that complements the C.cinereus rad9-1 mutation. Examination of this clone showed that it complements both the repair and meiotic defects of this mutant. Restriction fragment length polymorphism mapping using a portion of this clone showed that it maps to the rad9 locus. In addition, a single copy of transforming DNA is sufficient to complement the rad9-1 defects. Thus, we believe we have cloned the rad9 gene itself. We also used a chromosome-specific library and backcrossed isolates to rapidly identify a cosmid clone which is tightly linked to the rad11 locus and is therefore a suitable starting point for a chromosome walk. These rapid methods of gene mapping and isolation should be applicable to any organism with separable chromosomes.
Torben Iversen and Frances Rosenbluth. Women, Work, and Politics: The Political Economy of Gender Inequality

Torben Iversen and Frances Rosenbluth. Women, Work, and Politics: The Political Economy of Gender Inequality. New Haven: Yale University Press, 2010. ISBN 978-0300171341. In Women, Work, and Politi...
Application of physiologically based pharmacokinetic modelling to combination toxicology

Non-additive toxicity has been demonstrated in laboratory animals for a large number of temporally separated or concurrent multiple chemical exposures. These exposures are typically at concentrations higher than those found in the environment, leading to the question of the applicability of the results to the human situation. Physiologically based pharmacokinetic (PBPK) modelling has been applied successfully to single chemicals; its utility for extrapolation across species and dose has been demonstrated. Use of PBPK modelling in the study of chemical mixtures is increasing although still limited. The use of PBPK modelling by various investigators in the field of combination toxicology is reviewed. PBPK modelling has been used to examine: the role of increased metabolism in non-additive toxicity resulting from temporally separated exposures; the influence of the time interval separating two chemical exposures; and the role of inhibition of metabolism in concurrent exposure to two chemicals. In summary, development of a PBPK or PBPK/pharmacodynamic model for a combined exposure provides a basis for extrapolation across species, route and dose, and a useful tool for risk assessment.
The use of microchemical techniques for the identification of new transmitter molecules in neurons

The author reviews available microtechniques and results on cellular analysis of single neurons emphasizing the identification of putative neurotransmitter molecules. Highly sensitive microquantitative methods for identification and assay of known and putative neurotransmitters have been developed within the last 15 years. Several of the methods reported in the article fulfill the requirements of both specificity and sensitivity for exploring and measuring the level of transmitter molecules in single neurons. Some of the available techniques, mostly those which associate GC or TLC with MS, have been able to unambiguously demonstrate the presence of putative neurotransmitter molecules, or at least of substances which are strongly suspected of fulfilling a functional role in the nervous system.
Some observations of Np(VI) in chloride solutions

Results are given which show that the reduction of Np(Vl) in chloride media is very slow at room temperature, not differing greatly from that expected from auto-reduction, and that a satisfactory absorption spectrum can be obtained. The accelerated reduction observed in the presence of platinum is shown not to be due to a catalytic effect but to reduction by the platinum itself. The reduction of Np(VI) was iound to be a iittle faster in both DClO/sub 4/ and DCi in HClO/sub 4/ but still very slow. A major peak occurs at a longer wavelength in 2 M DCl than in 2 M DClO4 and its molar extinction coefficient is increased from 46 to 2 M DClO/sub 4/ to 54in2 M DCl. (P.C.H.)
Regulation of the Vibrio anguillarum Metalloprotease EmpA by Posttranslational Modification

The zinc metalloprotease EmpA is a virulence factor in the fish pathogen Vibrio anguillarum. Previous studies have shown that two strains of V. anguillarum regulate empA differently. Strain M93Sm exhibits protease activity only in the presence of fish gastrointestinal mucus, while protease activity is detected in NB10 culture supernatant under all stationary-phase conditions. In this study, we use real-time reverse transcription-PCR to show that even in conditions where no protease activity is detected, empA transcription occurs. Western blot analysis revealed that EmpA is secreted as a approximately 48-kDa proenzyme and that activation occurs extracellularly by the removal of a approximately 10-kDa peptide. The presence of stable extracellular pro-EmpA in M93Sm culture supernatants suggests that activation of EmpA is not autolytic.
Cigarette Smoke as a Cause of Small Irregular Opacities on Chest Radiographs

Asbestos, as well as other dusts and a variety of medical conditions, can cause irregular opacities to develop in the lung parenchyma. Although not widely accepted, some have suggested that cigarette smoke can produce these changes as well. This study looked at X-rays of individuals for whom smoking status was known, as well as an occupational history which precluded known dust exposure. There was no finding that smoking status contributed to the development of irregular opacities. As previously described, smoking does appear to increase the level of profusion caused by asbestos.
Superfluidity in sub-monolayer 3He–4He mixture films

Abstract We have studied the effect of 3 He dilution on very thin superfluid 4 He films using a torsional oscillator technique. Assuming that the inert layer is free of 3 He, we obtain data on films with 3 He concentration in the superfluid layer up to 80%. We compare our results with data available from earlier studies.
Comparison of stagnant versus anemic hypoxia during group B streptococcal sepsis in piglets

Abstract The relationships between cardiac index (CI), oxygen delivery (DO 2 ), oxygen consumption, and pH are not well characterized in human newborn sepsis or its models. In this experiment we attempted to discern whether reductions in CI, as distinct from reductions in DO 2 were related to the development of metabolic acidosis during group B streptococcal (GBS) sepsis. Eighteen piglets, 2 to 4 weeks old, were anesthetized, paralyzed, and mechanically ventilated. One group, SALINE (n = 6), did not receive GBS. The other two groups received identical, graded, continuous infusions of live GBS organisms for 4 hours. Piglets in the STAGNANT group (n = 6) suffered reduction of DO 2 due to GBS-induced reduction of CI (stagnant hypoxia). Piglets in the ANEMIC group (n = 6) received intravenous dextran and phlebotomy during GBS infusion to preserve CI at baseline while DO 2 was reduced (anemic hypoxia) to levels comparable to the STAGNANT group. By 240 minutes of GBS infusion, CI was significantly reduced in the STAGNANT piglets (104 to 43 mL/kg/min), but did not change significantly in the ANEMIC (120 to 105 mL/kg/min) or SALINE piglets (109 to 124 mL/kg/min). Oxygen delivery fell significantly in both the STAGNANT (14.2 to 5.7 mL O 2 /kg/ min) and ANEMIC piglets (16.8 to 7.3 mL O 2 /kg/min), but not in the SALINE group (15.0 to 15.6 mL O 2 /kg/min). Despite the differences in CI, pH fell equally and significantly over 4 hours of GBS infusion for STAGNANT (7.47 to 7.20) and ANEMIC piglets (7.45 to 7.22), but did not change for SALINE piglets (7.46 to 7.45). Likewise, base deficit rose equally and significantly for STAGNANT (-1.5 to 1 4.0 mEq/L) and ANEMIC (0.1 to 9.7 mEq/L) piglets, but did not change for SALINE piglets (1.2 to 2.4 mEq/L). Oxygen consumption did not change significantly for any group, and the oxygen extraction ratio rose significantly and equally for both STAGNANT (32% to 73%) and ANEMIC piglets (33% to 69%), but not for SALINE piglets (48% to 55%). These data suggest that changes in CI, independent of changes in DO 2 have little effect in the development of acidosis during GBS sepsis in piglets.
Jungle Geopolitics in Guyana: How a Communist Utopia That Ended in Massacre Came to be Sited

. When nearly 1,000 American men, women and children lost their lives in a mass murder and suicide rite in 1978 staged by a madman, Jim Jones, a former Christian minister turned Communist leader, many Americans asked, “Why?” The press, overcoming earlier lethargy, amassed facts permitting a sophisticated psychological and sociological explanation. Neglected, however, was the question why was the Jonestown Communist utopia sited in the Guyana jungle? Given the human and geographical circumstances, its siting in the Guyana rainforest was highly probable, affording evidence that, to some extent, at least, people and their geography determine human events.
Russian Tariffs and Foreign Industries before 1914: The German Entrepreneur's Perspective

The present study dealing with Russia and Germany undertakes to investigate the practical effect of tariffs on business and entrepreneur rather than the oft-discussed role of tariffs in international politics. Evidence from German industrial archives demonstrates that businesses were less concerned with tariff issues than one might expect from firms depending on exports. It shows that impediments other than customs duties (expenditures for credit, service, freight, investment, marketing; and competition, restrictions imposed on government orders, subventions, production costs abroad, technological changes) by far overshadowed inhibiting effects of tariffs. Circumspect responses of the entrepreneur helped to minimize the economic role tariffs played.
Factors associated with variations in parental social support in primary care pediatric settings.

Objective.—To examine social support (SS) among parents across sociodemographically distinct pediatric outpatient settings. Methods.—We conducted a cross-sectional, self-administered, anonymous parent survey in 3 primary care sites in a Midwestern metropolitan area: inner-city health center, urban group practice, and suburban group practice. Participants were parents of children aged 6 weeks to 36 months. The main outcome measure was overall SS as measured by a previously validated 10-item instrument. Multivariate linear regression modeling was used to examine sociodemographic and health factors associated with overall SS scores. Results.—The study sample included 463 parents. The strongest sources of SS were a significant other or spouse and parent's parent or grandparent. The range for overall SS was 0 to 20, with a mean score of 12.1 (SD, ±4.2). Parents with overall SS in the lowest quartile (n = 123) comprised 43% of parents at the inner-city health center compared with 23% of parents at the urban practice and 16% of parents at the suburban practice. In a multivariate model, factors associated with lower overall SS were race other than white or black, single or cohabitating marital status, poorer parental health, and parental depressive symptoms. Conclusions.—Although parental SS was lowest in the most socioeconomically disadvantaged community in this sample, parents in all 3 communities had widely varying levels of support. Providers may gain insights about parents at increased risk for low SS by asking about parents' own physical and mental health.