cssi/SciSciGPT-SciSciNet huggingface dataset:
The Role of Individual Cysteine Residues in the Activity of Escherichia coli RNase T

Escherichia coli RNase T, which is responsible for the 3' processing and end-turnover of tRNA and the maturation of 5 S RNA, is extremely sensitive to sulfhydryl reagents and to oxidation, suggesting a role for cysteine residues in its activity. Titration of homogeneous RNase T with 5,5'-dithiobis-(2-nitrobenzoic acid) revealed that the 4 cysteine residues present in each of the two protein subunits are in a reduced form and that 1 or 2 of them are important for activity. To identify these residue(s), each of the cysteines in RNase T was changed individually to either serine or alanine. The serine mutant at position 168 is greatly reduced in RNase T activity both in vivo and in vitro; likewise, the serine mutant at position 112 and the alanine mutants at positions 112 and 168 also display decreased RNase T activity. Mutations at the other cysteine positions show little or no change. Kinetic analyses of the mutant enzymes showed that the Km values of C168S and C168A are increased considerably, whereas their Vmax values are reduced only slightly compared to the wild type enzyme. The other mutant enzymes are little changed. Additional amino acid replacements at position 168 showed that the in vivo and in vitro activities of RNase T are in the order Cys approximately Val > Ala >> Ser >> Asn approximately Asp, which closely follows the relative hydrophobicity of these amino acid residues. However, the affinity for tRNA, determined by fluorescence quenching, is not altered in C168S, suggesting that Cys-168 is not directly involved in substrate binding. Interestingly, proteins altered at position 168 showed increased temperature sensitivity as the residue at that position became less hydrophobic. These data indicate that Cys-168 contributes a hydrophobic group that influences the structure and ultimately the catalytic activity of RNase T.
Gait mode recognition and control for a portable-powered ankle-foot orthosis

Ankle foot orthoses (AFOs) are widely used as assistive/rehabilitation devices to correct the gait of people with lower leg neuromuscular dysfunction and muscle weakness. We have developed a portable powered ankle-foot orthosis (PPAFO), which uses a pneumatic bi-directional rotary actuator powered by compressed CO2 to provide untethered dorsiflexor and plantarflexor assistance at the ankle joint. Since portability is a key to the success of the PPAFO as an assist device, it is critical to recognize and control for gait modes (i.e. level walking, stair ascent/descent). While manual mode switching is implemented in most powered orthotic/prosthetic device control algorithms, we propose an automatic gait mode recognition scheme by tracking the 3D position of the PPAFO from an inertial measurement unit (IMU). The control scheme was designed to match the torque profile of physiological gait data during different gait modes. Experimental results indicate that, with an optimized threshold, the controller was able to identify the position, orientation and gait mode in real time, and properly control the actuation. It was also illustrated that during stair descent, a mode-specific actuation control scheme could better restore gait kinematic and kinetic patterns, compared to using the level ground controller.
High order well-balanced finite volume WENO schemes and discontinuous Galerkin methods for a class of hyperbolic systems with source terms

Hyperbolic balance laws have steady state solutions in which the flux gradients are nonzero but are exactly balanced by the source term. In our earlier work [J. Comput. Phys. 208 (2005) 206-227; J. Sci. Comput., accepted], we designed a well-balanced finite difference weighted essentially non-oscillatory (WENO) scheme, which at the same time maintains genuine high order accuracy for general solutions, to a class of hyperbolic systems with separable source terms including the shallow water equations, the elastic wave equation, the hyperbolic model for a chemosensitive movement, the nozzle flow and a two phase flow model. In this paper, we generalize high order finite volume WENO schemes and Runge-Kutta discontinuous Galerkin (RKDG) finite element methods to the same class of hyperbolic systems to maintain a well-balanced property. Finite volume and discontinuous Galerkin finite element schemes are more flexible than finite difference schemes to treat complicated geometry and adaptivity. However, because of a different computational framework, the maintenance of the well-balanced property requires different technical approaches. After the description of our well-balanced high order finite volume WENO and RKDG schemes, we perform extensive one and two dimensional simulations to verify the properties of these schemes such as the exact preservation of the balance laws for certain steady state solutions, the non-oscillatory property for general solutions with discontinuities, and the genuine high order accuracy in smooth regions.
CONDITIONS FOR THE FORMATION OF "ACID-STIMULATING ACTIVITY" BY HYPERSENSITIVE CELLS IN CONTACT WITH ANTIGEN IN VITRO.

Abstract Peritoneal cells from sensitized guinea pigs upon incubation with the specific antigen yield an agent that stimulates KB epithelial cells in tissue culture to overproduce acid—a phenomenon referred to as "acid-stimulation activity" (ASA). The formation of ASA varied directly with the concentration of peritoneal cells, the concentration of antigen, and the temperature of incubation. Its rate of production was dependent upon the concentration of antigen, but with every concentration of antigen the rate was greatest during the first hour of incubation. With less than maximal concentrations of antigen, ASA formation continued beyond 1 hour, whereas with maximal concentrations of antigen, it significantly decreased after 1 hour. Cell death, lack of extracellular nutrients, and subthreshold levels of antigen were eliminated as reasons for failure of further production after 1 hour. In order to explain the results it has been postulated that an intracellular antibody-like substance has been exhausted.
The development of chloride ion selective polypyrrole thin film on a layer-by-layer carbon nanotube working electrode

A chloride ion selective thin film sensor is proposed for measuring chloride ion concentration, which is an environmental parameter correlated to corrosion. In this work, electrochemical polymerization of Polypyrrole (PPy) doped with chloride ions was achieved on the top of a carbon nanotube (CNT) thin film as a working electrode in an electrochemical cell. The underlying CNT layer conjugated with doped PPy thin film can form a multifunctional "selfsensing" material platform for chloride ion detection in a concrete environment. The paper presents the first type of work using CNT and PPy as hybrid materials for chloride ion sensing. Electrochemical polymerization of PPy results in oxidation that yields an average of one positive charge distributed over four pyrrole units. This positive charge is compensated by negatively-charged chloride ions in the supporting electrolyte. In effect, the chloride ion-doped PPy has become molecularly imprinted with chloride ions thereby providing it with some degree of perm-selectivity for chloride ions. The detection limit of the fabricated chloride ion-doped PPy thin film can reach 10-8 M and selectivity coefficients are comparable to those in the literature. The reported work aims to lay a strong foundation for detecting chloride ion concentrations in the concrete environment.
The Greeks as an alien minority at the outset of Ethiopia's economic development, 1880–1910

Abstract Between 1880 and 1910, Greeks constituted one of the largest foreign ethnic communities, in Ethiopia and as such they played an important role in the modernization efforts of Emperor Menilik II (1889–1913). During his reign, Ethiopia's modern economic development had its rudimentary beginnings when, with the participation of resident foreigners, he embarked on an ambitious, although haphazard program to raise his country's material standards. The Italian defeat at Adua in 1896 not only secured Ethiopian independence, but the absence of a single colonial ruler enabled Menilik to seek among various foreign groups the skills and resources necessary for economic development which were then lacking among the indigenous population. Greek participation in construction, internal and external commerce, and in petty retailing contributed to the foundation of Ethiopia's economic growth in the twentieth century.
Quantum physics: An atomic SQUID

Superconducting quantum circuits are the core technology behind the most sensitive magnetometers. An analogous device has now been implemented using a gas of ultracold atoms, with possible applications for rotation sensing.
Detached Eddy Simulation of Flow and Heat Transfer in a Stationary Internal Cooling Duct With Skewed Ribs

Numerical predictions of a hydrodynamic and thermally developed turbulent flow for a unit period of a stationary duct using Detached Eddy Simulation (DES) and Unsteady Reynolds Averaged Navier-Stokes (URANS) are presented. The domain under consideration is a square duct with 45° ribs on the top and bottom walls arranged in a staggered fashion. Computations are carried out for a bulk Re of 47,000. The rib height to channel hydraulic diameter (e/Dh ) is 0.1 and the rib pitch to rib height (P/e) is 10. DES is applied on two grids 80 × 80 × 80 and 128 × 80 × 80 and the initial results are compared with the experimental results and LES computations. Based on this the 128 × 80 × 80 grid is chosen for the comprehensive study. DES and URANS computations are carried out on the grid. The rib geometry introduces a strong secondary flow along the rib. The presence of the secondary flow introduces a spanwise variation in the heat transfer. DES predicts flow features and heat transfer distribution which is consistent with the experimental observations and LES computations. The average friction and the augmentation ratios predicted by DES also concur with the earlier observations.Copyright © 2005 by ASME
The socioeconomic consequences of young women's childbearing: Reconciling disparate evidence

Recent studies have begun to examine rigorously the links between early childbearing and subsequent socioeconomic status. Prominent in this literature has been a set of analyses that have used sibling fixed effects models to control for omitted variables bias. These studies report that the siblings difference procedure leads to smaller estimates of the effects of teen fertility than does standard regression analysis. While it is well known that the siblings fixed effects procedure makes strong assumptions regarding the type of omitted variables and is not necessarily robust to alternative assumptions, the assumptions of the procedure have not been explicitly examined. This paper uses 1979-1992 data from the National Longitudinal Survey of Youth to compare estimates of the income and education consequences of teenage and young adult fertility from standard regression and siblings fixed effects models with estimates from more general, alternative siblings models. JEL classification: J13
Maternal toxicity and teratogenicity of tellurium dioxide in the Wistar rat: relationship to pair-feeding.

Tellurium dioxide (TeO2) induces hydrocephalus, edema, exophthalmia, ocular hemorrhage, umbilical hernia, undescended testes and small kidneys in day 20 Wistar rat fetuses when administered s.c. to pregnant dams from gestational day 15 to 19. At doses of 500 mumole/kg or greater, a 100% incidence of these findings and a reduction in maternal weight gain were observed. A pair-fed study at the dose of 500 mumole/kg of TeO2 was conducted to establish if the effects of tellurium were a result of a reduction in food intake or other maternal toxic responses. Two additional control groups of rats receiving tellurium or vehicle were fed ad libitum. After a comparable maternal weight gain from day 0 to 15, weight gain was significantly reduced in the treated groups and the pair-fed control. There was a reduction of fetal weight in the treated groups (p less than 0.01) and in the pair-fed control (p less than 0.02). There was a 100% incidence of the above anomalies in the litters of the two treated groups, but none in the pair-fed and control groups. No histological alterations other than a mild centrolobular fatty change in the liver were detected in the other organs from the tellurium exposed dams. Thus, tellurium induces both maternal toxicity and teratogenic effects in the rat where the teratogenicity is not mediated by alterations in the diet.
A preliminary investigation of emotions experienced toward god by catholic nuns and priests

Bilan d'une etude preliminaire des emotions ressenties envers Dieu par 22 ecclesiastiques des deux sexes d'apres leurs evaluations d'une liste de 50 emotions
A large deviation theory proof of the abstract alphabet source coding theorem

A modified proof of T. Berger's (1971) abstract alphabet source coding with a fidelity criterion theorem is provided, utilizing a variant of a result from large deviation theory. This proof does not use an asymptotic equipartition property of any kind, thus providing what appears to be a more direct approach to this key result. >
Speech enhancement by Fourier-Bessel coefficients of speech and noise

The speech enhancement problem is approached by the Fourier–Bessel (FB) expansion of the speech and noise. The application of this expansion to the enhancement of the speech signals degraded with additive noise is described. The method is based on the subtraction of the FB coefficients of the estimated noise from the coefficients of the noisy speech. The difference in two sets of coefficients is then used to synthesise the enhanced speech. The inherent lowpass filtering property of the FB reconstruction with a finite number of coefficients is revealed.
The specific binding of androgens and the subsequent distribution of androgen-receptor complexes within MCF-7 human breast cancer cells.

Abstract Using a whole cell suspension assay technique, we have examined both the specific binding of testosterone (T) and dihydrotestosterone (17β-hydroxy-5α-androstan-3-one) (DHT) and the subsequent distribution of androgen binding activity within MCF-7 human breast cancer cells. We have observed that both androgens are bound with high affinity to the same single class of receptor which is present at a concentration of approximately 8,000 sites per cell. The incubation of cells with either T or DHT was followed by the nuclear accumulation of specifically bound ligand which increased to maximal values within 1 h and then decreased thereafter. However, only about 30% of the total cellular specific binding activity observed with either androgen was localized within the nuclear compartment at any time during a 4 h incubation. Further examination of the extranuclear binding component suggested that a substantial portion of this activity was localized to the particulate fraction of the cytoplasm. The results of these studies suggest that both T and DHT are capable of exerting biological activity within MCF-7 cells, and raise the interesting possibility that androgen-receptor complexes may participate in the direct regulation of mitochondrial and/or microsormal function in this system.
Electrolysis-based diaphragm actuators

This work presents a new electrolysis-based microelectromechanical systems (MEMS) diaphragm actuator. Electrolysis is a technique for converting electrical energy to pneumatic energy. Theoretically electrolysis can achieve a strain of 136 000% and is capable of generating a pressure above 200 MPa. Electrolysis actuators require modest electrical power and produce minimal heat. Due to the large volume expansion obtained via electrolysis, small actuators can create a large force. Up to 100 µm of movement was achieved by a 3 mm diaphragm. The actuator operates at room temperature and has a latching and reversing capability.
Refractive surgery for special needs children.

These are the hard cases and the children with greatest need. Their spherical-equivalent myopia or hyperopia exceeds approximately 4 to 5 diopters (D). The uncorrected myopia translates to a distant acuity of 20/200 or worse (legal blindness). The uncorrected acuity for the child with hyperopia can be better during epochs when the child accommodates partially, but accommodation is often impaired in children with neurobehavioral disorders. The prevalence of isoametropic amblyopia in children with uncorrected high hyperopia approaches 50%. Add to this the substantial risk (about 80%) of refractive esophoria or esotropia. A variety of neurobehavioral disorders impede spectacle wear. The most common are moderate to severe cerebral palsy (ie, Gross Motor Function Classification Scale levels 3-5), autism, Angelman syndrome, more severe Down syndrome, and suboptimally controlled seizure disorders. Other causes are idiopathic developmental delay/ mental retardation and progressive childhood encephalopathies. The uncorrected ametropia exacerbates the neurobehavioral disorder. The child lives in a cocoon of blur, promoting fearfulness, reduced interest in the outside world, and blunted social interactions (a constellation labeled “visual autism”). The extreme refractive error is seldom the only visual deficit. Common comorbidities include strabismus, amblyopia, optic neuropathies, foveopathies, and nystagmus. Comorbidities do not mean that the refractive error is unimportant or that correcting the error would not improve visual function. Too many ophthalmologists, after examining a child with an intimidating array of neurobehavioral and visuomotor deficits, succumb to the bigotry of low expectations. The uncorrected vision is dismissed as “good enough for a child with multiple disabilities.” Why is prescribing glasses ineffective in a substantial fraction of these children? Many are aversive to wearing any head or facial appliance. They dislodge glasses repeatedly, despite heroic efforts to enforce compliance on the part of parents, teachers, therapists, and caregivers. If the battle is won to keep the glasses in place, the benefit may be negated by poor motor control of the head, neck, and trunk or gaze palsies and apraxias. The motorcontrol disorders cause chronic viewing over, around, or at the edges of spectacle lenses. Contact lenses are seldom a suitable option. Insertion and removal may require bodily restraint by multiple family members and vigorous eyelid manipulation to overcome intense blepharospasm. Repeated rounds of this exhaust— physically and emotionally—even the most committed parents.
Characterization of unstable poly(A)-RNA in Caulobacter crescentus

Abstract A significant amount of poly(A)-RNA in Caulobacter crescentus is located on polysomes and the size distribution of this polysomal poly(A)-RNA is small compared to the total pulse-labeled RNA in these cells. These observations suggest that the poly(A)-RNA represents a subset of small messenger RNA molecules. Poly(A)-RNA, and presumably the poly(A) portion of these molecules, is extremely unstable: as assayed by binding to oligo(dT)-cellulose the poly(A)-RNA turns over with a chemical half-life of 15–20 s compared to a half-life of approx. 2 min for total cellular messenger RNA. The presence of adenosine in hydrolysates of poly(A) tracts showed that these sequences are located at the 3′-OH end of the RNA. The ratios of AMP/adenosine in the samples confirmed that the length of the A-tracts is approx. 13–17 nucleotides (Ohta, N., Sanders, M. and Newton, A. (1975) Proc. Natl. Acad. Sci. U.S.A. 72, 2343–2346).
Micro-computed tomography prediction of biomechanical strength in murine structural bone grafts

Correlating massive bone graft strength to parameters derived from non-invasive imaging is important for pre-clinical and clinical evaluation of therapeutic adjuvants designed to improve graft repair. Towards that end, univariate and multivariate regression between measures of graft and callus geometry from micro-CT imaging and torsional strength and rigidity were investigated in a mouse femoral graft model. Four millimeter mid-diaphyseal defects were grafted with live autografts or processed allografts and allowed to heal for 6, 9, 12, or 18 weeks. We observed that allograft remodeling and incorporation into the host remained severely impaired compared to autografts mainly due to the extent of callus formation around the graft, the rate and extent of the graft resorption, and the degree of union between the graft and host bone as judged by post-mechanical testing analysis of the mode of failure. The autografts displayed greater ultimate torque and torsional rigidity compared to the allografts over time. However the biomechanical properties of allografts were equivalent to autografts by 9 weeks but significantly decreased at 12 and 18 weeks. Multivariate regression analysis demonstrated significant statistical correlations between combinations of the micro-CT parameters (graft and callus volume and cross-sectional polar moment of inertia) with the measured ultimate torque and torsional rigidity (adjusted R(2)=44% and 50%, respectively). The statistical correlations approach used in this mouse study could be useful in guiding future development of non-invasive predictors of the biomechanical properties of allografts using clinical CT.
Developing the Brand: The Case of Alcohol, 1800-1880

Historians generally agree that modern brands arose from the vertically integrated corporations of the late nineteenth and early twentieth centuries and were used as competitive weapons between like firms. Looking at the alcoholic beverage trade and drawing on trade press, court reports, newspaper advertising, business records, and accounts of consumer behavior, I suggest that, on the contrary, supply chains made up of small firms played both an earlier and a significant part in the genesis of modern brands. In these chains, firms used branding not only to fight direct competitors but also to discipline and subordinate other links in the chain over whom they had no direct control and with whom they had to cooperate.
Sedimentation in Multicomponent Systems

The formalism of irreversible thermodynamics is employed to derive expressions for the sedimentation coefficients of the species in a multicomponent system in terms of experimentally accessible quantities. Equations are presented for certain limiting cases which may be encountered experimentally. The determination of the hydration of macromolecules by sedimentation methods is examined.
Emerging ocean observations for interdisciplinary data assimilation systems

Identification, understanding, and prediction of many interdisciplinary oceanographic processes remain as elusive goals of ocean science. However, new ocean technologies are being effectively used to increase the variety and numbers of sampled variables and thus to fill in the gaps of the time-space continuum of interdisciplinary ocean observations. The formulation, accuracy, and efficacy of data assimilative models are highly dependent upon the quality and quantity of interdisciplinary observational data. In turn, the design of optimal sampling networks will benefit from data assimilative-based observation system simulation experiments (OSSEs). The present contribution, which is directed toward both modelers and observationalists, reviews emerging interdisciplinary observational capabilities and their optimal utilization in data assimilative models.
An Examination of How Leadership Style Influences Team Performance through Conflict

Whereas transformational leadership is positively related to team performance, the impact of transactional leadership on team performance is mixed. We hypothesized that leadership style influences ...
Medical Humanitarianism and Physicians' Organized Efforts to Provide Aid to Unauthorized Migrants in Germany

Universal notions of a "right to health" for unauthorized migrants operate together with incongruous state and international policies. These ambivalent policies demand ethnographic attention, since they have resulted in a two-tiered system in host countries and foster short-term, improvisational remedies. Medical care for unauthorized migrants is typically left in the hands of non-governmental organizations (NGOs) and permitted under the guise of sympathy and generosity rather than anchored in policy. This paper draws upon ethnographic fieldwork in Germany to present the viewpoints of physicians engaged in medical humanitarianism and discuss the complications associated with filling access gaps through NGOs. It explores the range of motivations—political, religious, and humanitarian—that drive physicians to provide care to marginalized populations. In recent years, I argue that NGO demands upon the state have moved from requests to decriminalize medical aid to demands for compensation for the significant ...
Wall heat storage in displacement compressors

The role of cyclic heat transfer between the walls of a piston/cylinder and the gas being compressed is investigated from the point of view of thermodynamic performance. It is shown that the adiabatic efficiency depends directly on the amount of heat transferred which in turn depends on the operating parameters as well as material from which the compressor is constructed. It is shown that for good high pressure ratio performance, the cylinder head, the piston head and the upper section of the cylinder must be built with materials of low thermal conductivity. Candidate materials are found in the ceramic family of silicon compounds, among others.
The BEAM method for neurophysiological diagnosis.

Cartographie de l'activite electrique cerebrale (Brain Electric Activity Mapping) dans l'etude de: dyslexie, epilepsie, schizophrenie, senescence cerebrale, demence presenile et senile, fonction cerebrale des prematures
Spectral development of a solar X-ray burst observed on OSO-7

The UCSD solar X-ray instrument on the OSO-7 satellite observes X-ray bursts in the 2–300 keV range with 10.24 s time resolution. Spectra obtained from the proportional counter and scintillation counter are analyzed for the event of November 16, 1971, at 0519 UT in terms of thermal (exponential spectrum) and non-thermal (power law) components. The energy content of the approximately 20 × 106K thermal plasma increased with the 60 s duration hard X-ray burst which entirely preceded the 5 keV soft X-ray maximum. If the hard X-rays arise by thick target bremsstrahlung, the nonthermal electrons above 10 keV have sufficient energy to heat the thermally emitting plasma. In the thin target case the collisional energy transfer from non-thermal electrons suffices if the power law electron spectrum is extrapolated below 10 keV, or if the ambient plasma density exceeds 4 × 1010 cm−3.
Voices in Conversation: Philosophy and Politics in the Work of Michael Oakeshott

It is commonplace to suggest that Michael Oakeshott maintained a strict separation of philosophy from politics throughout his work. I challenge this prevailing view by suggesting that Oakeshott abandoned his early idealism on which the strict separation was based. I argue instead that from the 1940s onward, Oakeshott cautiously conceived of a more contingent and open relationship for theory and practice. This relationship is best typified by his adoption of the image of voices in conversation. Finally, I suggest that this understanding of Oakeshott's skeptical and ironical character lends support to Richard Rorty's appropriations of Oakeshott as a fellow "liberal ironist."
Permutations with one or two 132-subsequences

Abstract We prove a strikingly simple formula for the number of permutations containing exactly one subsequence of type 132. We show that this number equals the number of partitions of a convex ( n + 1)-gon into n − 2 parts by noncrossing diagonals. We also prove a recursive formula for the number d n of those containing exactly two such subsequences, yielding that { d n } is P -recursive.
A Quantitative Relation between the Experimentally Determined Number of Conceptuses and Corpus Luteum Activity in the Pregnant Rat

The relation between the number of live conceptuses in the uterus in pregnant rats bearing a full complement of corpora lutea (CL) and the growth of the CL and their rate of progesterone secretion after day 12 was determined by aspirating all but the desired number of conceptuses on day 7 of pregnancy (day 1 = insemination). In one series of rats, bearing 0, 1, 2, 3, 4, 5–7, or 10 or more conceptuses, the weights of the CL and the serum progesterone levels were measured on days 12 and 15; in another, consisting of rats with 0, 1, or 10 or more conceptuses, the serum progesterone level was measured on days 12, 15, 17, 19, and 21. There was a direct relation between the number of conceptuses, the size of the CL, and the serum progesterone level on day 15. The maximum normal values for both parameters of CL activity were found in rats with 4 or 5 or more conceptuses. In the rats bearing 10 live conceptuses, the serum progesterone levels rose and fell between days 12–21, very much as has been described for no...
Federal Civil Rights Policy and Mental Health Treatment Access for Persons with Limited English Proficiency.

As noted in the supplement to the U.S. Surgeon General's report on mental health (U.S. Department of Health and Human Services, 2001), overcoming language access barriers associated with limited English proficiency (LEP) should help to eliminate racial and ethnic disparities in mental health care access and quality. Federal policy requires remedial action to overcome language barriers: Under Title VI of the Civil Rights Act of 1964, Medicaid and other federally funded programs must provide assistance to LEP persons. Some state-level public and mental health authorities have responded by instituting "threshold language" policies. The history and terms of federal civil rights policy, and of threshold-language-policy-inspired initiatives, should be understood by everyone concerned with overcoming ethnic disparities in mental health services use. Concerned parties should promote implementation of required measures for language assistance and help to evaluate their implementation and effectiveness.
The accuracy of first‐order density matrices obtained by electronic structure methods involving the valence electrons only

First‐order density matrices are obtained from all‐electron unrestricted‐Hartree–Fock (UHF) calculations and from effective‐core‐potential valence‐electron UHF calculations for the silicon and argon atoms, and for the Si2 molecule. The density matrices are compared by means of their derived X‐ray scattering factors, directional Compton profiles, and the charge density, at selected points in k and r space.
Known Unknowns in Exocytosis

Despite the immense progress in identifying the essential molecules in the exocytotic pathway and the award of the 2013 Nobel Prize in Physiology and Medicine to colleagues in the field, gaps continue to exist in our understanding of the most fundamental aspects of the process. The intent of the talk is to highlight some of the known unknowns and present recent (surprising) results concerning the regulation of the fusion pore by the very proteins that are being discharged upon fusion.
Mesocellular Silica Foam as an Epoxy Polymer Reinforcing Agent

A new type of mechanically improved rubbery epoxy composite is demonstrated based on the use of a mesocellular silica foam, denoted MSU-F, as the reinforcement agent. The silica exhibits a surface area of 540 m2 g–1, a cell size of 26.5 nm (14.9 nm window size) and a pore volume of 2.2 cm3 g–1. Most notably, the silica foam particles readily disperse in the epoxy matrix without the need for an organic surface modifier or dispersing agent. Relative to the pristine polymer, the tensile modulus, strength, strain-at-break, and toughness for the mesocomposites are systematically enhanced at relatively low silica loading over the range 1–9 wt %. Moreover, all of these benefits are realized without a sacrifice in thermal stability or optical transparency of the polymer. The results demonstrate that silica in mesocellular foam form can provide polymer reinforcement far beyond the level realized for non-porous silica or silica with small mesopores at the same weight loading.
Delayed, reversible hearing loss caused by difluoromethylornithine (DFMO).

Objectives/Hypothesis Difluoromethylornithine (DFMO) is an anticancer experimental drug that is ototoxic. The objectives of these three experiments were to: 1) determine a dose and dosing schedule of DFMO that produces significant hearing loss (HL) in newborn gerbils; 2) compare the HL level for control and newborn gerbils receiving daily subcutaneous injections of DFMO; and 3) to determine if DFMO-related HL is significantly reversible following discontinuation of DFMO treatment. Study Design Prospective, non-randomized experimental design with placebo controls. Methods Click-evoked auditory brainstem response (ABR) testing was performed for 21-day-old Mongolian gerbils following daily subcutaneous injections of DFMO or saline. Three experiments were carried out using different injection schedules and doses of DFMO. In experiment 3, animals were retested at 42 days of age following a 3-week recovery from DFMO. Results Animals administered an 18-day regimen of DFMO at 1 g/kg per day (from day 3 to day 20) had click thresholds of 25 to 65 dB nHL, whereas animals receiving daily injections of saline had thresholds of 5 to 20 dB nHL. Animals retested after 3 weeks of recovery from DFMO treatment had thresholds ranging from 5 to 20 dB nHL. Differences were statistically significant. Conclusions DFMO causes mild to moderate HL in neonatal gerbils that recovers after discontinuation of the drug.
Association of environment and policy characteristics on children's moderate-to-vigorous physical activity and time spent sedentary in afterschool programs.

Abstract Background Afterschool programs are an important setting in which to promote children's physical activity. This study examines the association of environmental and policy characteristics on the moderate-to-vigorous physical activity and sedentary behavior of children attending afterschool programs. Methods A total of 1302 children attending 20 afterschool programs across South Carolina wore accelerometers (ActiGraph GT3X +) for up to 4 non-consecutive days. Policy-level characteristics were evaluated using the Healthy Afterschool Program Index-Physical Activity scale. Physical activity space was measured using a measuring wheel (indoor, ft2) and Geographical Information Systems software (outdoor, acres). The structure (free-play or organized) of activity opportunities was evaluated via direct observation. Time spent in moderate-to-vigorous physical activity and sedentary, both indoors and outdoors, was estimated using accelerometry. Results For every 5000 ft2 of utilized indoor activity space an additional 2.4 and 3.3 min/day of sedentary behavior was observed among boys and girls, respectively. A higher ratio of free-play to organized play was associated with higher indoor sedentary behavior among boys and girls (3.9 min/day and 10.0 min/day, respectively). For every 1 acre of outdoor activity space used, an additional 2.7 min/day of moderate-to-vigorous physical activity was observed for boys. A higher free-play to organized play ratio was associated with higher outdoor moderate-to-vigorous physical activity for boys and girls (4.4 and 3.4 min/day increase, respectively). Policy characteristics were unrelated to moderate-to-vigorous physical activity levels and time spent sedentary. Conclusion Findings indicate that policies and size of activity space had limited influence on moderate-to-vigorous physical activity and sedentary behavior, suggesting that a programmatic structure may be a more effective option to improve moderate-to-vigorous physical activity levels of children attending afterschool programs.
High Density Lipoprotein Prevents Oxidized Low Density Lipoprotein-induced Inhibition of Endothelial Nitric-oxide Synthase Localization and Activation in Caveolae

Oxidized LDL (oxLDL) depletes caveolae of cholesterol, resulting in the displacement of endothelial nitric-oxide synthase (eNOS) from caveolae and impaired eNOS activation. In the present study, we determined if the class B scavenger receptors, CD36 and SR-BI, are involved in regulating nitric-oxide synthase localization and function. We demonstrate that CD36 and SR-BI are expressed in endothelial cells, co-fractionate with caveolae, and co-immunoprecipitate with caveolin-1. Co-incubation of cells with 10 microgram/ml high density lipoprotein (HDL) prevented oxLDL-induced translocation of eNOS from caveolae and restored acetylcholine-induced nitric-oxide synthase stimulation. Acetylcholine caused eNOS activation in cells incubated with 10 microgram/ml oxLDL (10-15 thiobarbituric acid-reactive substances) and blocking antibodies to CD36, whereas cells treated with only oxLDL were unresponsive. Furthermore, CD36-blocking antibodies prevented oxLDL-induced redistribution of eNOS. SR-BI-blocking antibodies were used to demonstrate that the effects of HDL are mediate by SR-BI. HDL binding to SR-BI maintained the concentration of caveola-associated cholesterol by promoting the uptake of cholesterol esters, thereby preventing oxLDL-induced depletion of caveola cholesterol. We conclude that CD36 mediates the effects of oxLDL on caveola composition and eNOS activation. Furthermore, HDL prevents oxLDL from decreasing the capacity for eNOS activation by preserving the cholesterol concentration in caveolae and, thereby maintaining the subcellular location of eNOS.
Putting the brakes on insulin signaling.

The discovery of a molecule that interferes with a component of the insulin-signaling pathway provides a target for drug development.
Kainic acid-induced sprouting of dynorphin- and enkephalin- containing mossy fibers in the dentate gyrus of the rat hippocampus

Abstract This study utilized Timm histochemistry and immunocytochemistry to determine the prolonged effects of kainic acid on the distribution of dynorphin- and enkephalin-containing mossy fibers in the rat dentate gyrus at progressive time points following kainic acid injection. Beginning 1–2 weeks after kainic acid administration, a progressive increase in the distribution and intensity of staining for supragranular zinc, dynorphin and enkephalin was observed in the dentate gyrus. The kainic acid-induced sprouting of mossy fibers containing dynorphin and enkephalin strongly resembles the pattern observed in the dentate gyrus of humans with temporal lobe epilepsy.
Comparative Variation in Spawning Output and Juvenile Recruitment of Some Caribbean Reef Fishes

It is generally accepted that the intensity of recruitment of pelagic young of temperate marine fishes is determined primarily by events that affect young as larvae, and that pelagic processes substantially increase variation in recruitment over the level expected from variation in spawning output alone. Spawning and recruitment of 6 species of Caribbean damselfishes were monitored monthly at a site in Panama for 1 to 3 yr (1983 to 1987) and 7 to 10 yr (1980 to 1989), respectively. Intermensual variation in recruitment strength exceeded corresponding variation in spawning output by average factors of at least 1.5 to 3.0 (and perhaps as much as 4 to 20) among those species. Serial changes in seasonally-adjusted monthly spawning output and 'resultant' recruitment strength were not correlated in any species. Thus, regardless of whether or not local populations are self-recruiting, pelagic processes evidently do largely control, and substantially enhance, short-term variabihty in recruitment strength in these fishes. Interannual variation in recruitment was low in all but one species. in which it also exceeded variation in spawning. Thus control of variation in recruitment strength by short-term pelagic processes had little or no net effect on interannual variation in recruitment in most cases. Interspecific differences in recruitment seasonal~ty and in levels of variation in mensual and annual recruitment strength (but not mensual and annual spawning output) ~ndicate that pelagic processes affect recruitment of some of these closely related species to different degrees and in different temporal patterns.
Discordance between N-acetyltransferase 2 phenotype and genotype in a population of Hmong subjects.

Polymorphisms of N-acetyltransferase 2 (NAT2) acetylation may influence drug toxicities and efficacy and are associated with a differential susceptibility to select cancers. Acetylation phenotype may have clinical implications. The purposes of this study were to determine the genetic basis of an apparent predominance of slow acetylation phenotype and to assess concordance with genotype in a population of Hmong residing in Minnesota. Urine and DNA obtained from unrelated Hmong 18 to 65 years of age were used to determine phenotype from caffeine metabolites, whereas direct nucleotide sequencing of the NAT2 coding region, followed by cloning, identified all known allelic variants. From 61 subjects (27 men, 30 ± 11 years), analysis of 50 urine-DNA pairs identified 46 (92%) slow acetylators and 4 (8%) rapid acetylators by phenotype. Genotypic analysis inferred 5 (10%) slow acetylators and 45 (90%) rapid acetylators. There is 86% discordance between phenotype and genotype. A predominance of NAT2 slow acetylation phenotype in the Hmong is confirmed, and a significant discordance between NAT2 phenotype and genotype is identified. In this population, slow acetylation phenotype determined by a metabolic probe would not have been predicted by genotype alone. Environmental, genetic, or phenotypic anomalies that may contribute to this discordance should be considered and evaluated in future studies within this unique population.
A Handy User’s Guide to Computers and Composition

Abstract This article is a visual essay that uses images of hands and computers to articulate the physical experience and ephemeral quality mediating between the physical act of keyboarding and the process of communication as we live with our computers.
Approximation algorithms for partially covering with edges

The edge dominating set (EDS) and edge-cover (EC) problems are classical graph covering problems in which one seeks a minimum cost collection of edges which covers the edges or vertices, respectively, of a graph. We consider the generalized partial cover version of these problems, in which failing to cover an edge, in the EDS case, or vertex, in the EC case, induces a penalty. Given a bound on the total amount of penalties that we are permitted to pay, the objective is to find a minimum cost cover with respect to this bound. We give an 8/3-approximation for generalized partial EDS. This result matches the best-known guarantee for the {0,1}-EDS problem, a specialization in which only a specified set of edges need to be covered. Moreover, 8/3 corresponds to the integrality gap of the natural formulation of the {0,1}-EDS problem. Our techniques can also be used to derive an approximation scheme for the generalized partial edge-cover problem, which is NP-complete even though the uniform penalty version of the partial edge-cover problem is in P.
Leasing and credit risk

Abstract Despite empirical evidence pointing to a strong similarity between lease contracts and junk bonds, the theoretical modeling of equilibrium lease determination has been confined primarily to default-free leases. This paper provides a unified framework for determining the equilibrium credit spread on leases subject to default risk. The model is flexible enough to be applied to a wide variety of real-world leasing structures, including security deposits, required up-front prepayments, embedded lease options, leases indexed to use, and lease credit insurance contracts.
GPU acceleration of Algebraic Multigrid for low-frequency finite element methods

This paper introduces a GPU acceleration of a Wavelet-based Algebraic Multigrid used as preconditioner for solving the Laplace's equation discretized by Finite Element Method. We conduct some tests using a CPU-based direct solver, a CPU-based Preconditined Conjugate Gradient (PCG), and a GPU-based PCG. Finally, we report the solution time and the speed-up achieved in solving the discretized problem.
Accelerator Mass Spectrometry for Measurement of Long-Lived Radioisotopes

Particle accelerators, such as those built for research in nuclear physics, can also be used together with magnetic and electrostatic mass analyzers to measure rare isotopes at very low abundance ratios. All molecular ions can be eliminated when accelerated to energies of millions of electron volts. Some atomic isobars can be eliminated with the use of negative ions; others can be separated at high energies by measuring their rate of energy loss in a detector. The long-lived radioisotopes (10)Be, (14)C,(26)A1, 36Cl, and (129)1 can now be measured in small natural samples having isotopic abundances in the range 10(-12) to 10(- 5) and as few as 10(5) atoms. In the past few years, research applications of accelerator mass spectrometry have been concentrated in the earth sciences (climatology, cosmochemistry, environmental chemistry, geochronology, glaciology, hydrology, igneous petrogenesis, minerals exploration, sedimentology, and volcanology), in anthropology and archeology (radiocarbon dating), and in physics (searches for exotic particles and measurement of halflives). In addition, accelerator mass spectrometry may become an important tool for the materials and biological sciences.
Clonal growth and culture life span of bovine adrenocortical cells in a serum-free medium.

The life span and growth from clonal density of bovine adrenocortical cell cultures were studied in serum-supplemented medium and a serum-free defined medium, which supported sustained cell proliferation and steroid production. The total culture life span was 79 population doublings in serum-supplemented medium with fibroblast growth factor (FGF) and 36 population doublings in the defined medium without serum. Older passage cell cultures grown in the defined medium progressively lost the ability to produce 11β- and 21-hydroxylated steroids, which was observed previously for cultures in serum-supplemented medium, and also had a decline of 17α-hydroxylated steroid production. The cloning efficiency in the defined medium was 12.2% as compared to 24% in serum-supplemented medium with FGF. Five isolated clonal cell lines grown in the defined medium were characterized for steroid function in response to steroidogenic agents. All five clonal cell lines had stimulated steroid production with 8-bromo-cAMP, but only four of the clonal lines were stimulated also by adrenocorticotropin. None of the clonal cell lines produced 11β-, 21- or 17α-hydroxylated steroids in response to treatment with either steroidogenic agent, results that were similar to data obtained from older mass cultures. The apparent deficiency of the defined medium as compared to serum-supplemented medium for maximum support of the culture life span and cloning efficiency may be useful in studies of cellular aging and its relation to differentiated function for this cell culture system.
Lateral approach to the popliteal artery

Techniques for exposure of the popliteal artery via lateral approaches above and below the knee are described. These techniques were used successfully in 21 patients who required secondary arterial reconstructions in the presence of extensive scarring, infection, or both in the standard medial access routes.