cssi/SciSciGPT-SciSciNet huggingface dataset:
Roles of organizer factors and BMP antagonism in mammalian forebrain establishment.

Abstract A critical question in mammalian development is how the forebrain is established. In amphibians, bone morphogenetic protein (BMP) antagonism emanating from the gastrula organizer is key. Roles of BMP antagonism and the organizer in mammals remain unclear. Anterior visceral endoderm (AVE) promotes early mouse head development, but its function is controversial. Here, we explore the timing and regulation of forebrain establishment in the mouse. Forebrain specification requires tissue interaction through the late streak stage of gastrulation. Foxa2−/− embryos lack both the organizer and its BMP antagonists, yet about 25% show weak forebrain gene expression. A similar percentage shows ectopic AVE gene expression distally. The distal VE may thus be a source of forebrain promoting signals in these embryos. In wild-type ectoderm explants, AVE promoted forebrain specification, while anterior mesendoderm provided maintenance signals. Embryological and molecular data suggest that the AVE is a source of active BMP antagonism in vivo. In prespecification ectoderm explants, exogenous BMP antagonists triggered forebrain gene expression and inhibited posterior gene expression. Conversely, BMP inhibited forebrain gene expression, an effect that could be antagonized by anterior mesendoderm, and promoted expression of some posterior genes. These results lead to a model in which BMP antagonism supplied by exogenous tissues promotes forebrain establishment and maintenance in the murine ectoderm.
High mobility p-channel HFETs using strained Sb-based materials

Antimonide-based p-channel HFETs with a 0.25 mum gate length have been fabricated with an InAlSb/AlGaSb barrier and a strained In 0.41 Ga 0.59 Sb quantum well channel. The modulation-doped material exhibits a Hall mobility of 1020 cm 2 /Vs and a sheet density of 1.6 x 10 12 cm -2 . The devices have a maximum DC transconductance of 133 mS/mm and an f T and f max of 15 and 27 GHz, respectively. These values are the highest reported to date for this material system.
Effects of internal mixing and aggregate morphology on optical properties of black carbon using a discrete dipole approximation model

Abstract. According to recent studies, internal mixing of black carbon (BC) with other aerosol materials in the atmosphere alters its aggregate shape, absorption of solar radiation, and radiative forcing. These mixing state effects are not yet fully understood. In this study, we characterize the morphology and mixing state of bare BC and BC internally mixed with sodium chloride (NaCl) using electron microscopy and examine the sensitivity of optical properties to BC mixing state and aggregate morphology using a discrete dipole approximation model (DDSCAT). DDSCAT is flexible in simulating the geometry and refractive index of particle aggregates. DDSCAT predicts a higher mass absorption coefficient (MAC), lower single scattering albedo (SSA), and higher absorption Angstrom exponent (AAE) for bare BC aggregates that are lacy rather than compact. Predicted values of SSA at 550 nm range between 0.16 and 0.27 for lacy and compact aggregates, respectively, in agreement with reported experimental values of 0.25 ± 0.05. The variation in absorption with wavelength does not adhere precisely to a power law relationship over the 200 to 1000 nm range. Consequently, AAE values depend on the wavelength region over which they are computed. The MAC of BC (averaged over the 200–1000 nm range) is amplified when internally mixed with NaCl (100–300 nm in radius) by factors ranging from 1.0 for lacy BC aggregates partially immersed in NaCl to 2.2 for compact BC aggregates fully immersed in NaCl. The SSA of BC internally mixed with NaCl is higher than for bare BC and increases with the embedding in the NaCl. Internally mixed BC SSA values decrease in the 200–400 nm wavelength range, a feature also common to the optical properties of dust and organics. Linear polarization features are also predicted in DDSCAT and are dependent on particle size and morphology. This study shows that DDSCAT predicts complex morphology and mixing state dependent aerosol optical properties that have been reported previously and are relevant to radiative transfer, climate modeling, and interpretation of remote sensing measurements.
Wild Man: The Life and Times of Daniel Ellsberg

On September 4, 1971, the office of Lewis Fielding, a psychiatrist practicing in Los Angeles, was broken into. It looked like a run of the mill drug raid. A month later, a homeless man was charged with burglary and the case was considered closed. On June 17, 1972, five men were charged with breaking and entering at the headquarters of the Democratic National Committee in the Watergate Hotel in Washington, D.C. With these two burglaries, one seemingly innocuous while the other was more serious because of the venue, the scandal known as Watergate was born. As the tale of Richard Nixon and his Plumbers began to unfold, it was discovered that one of Lewis Fielding's patients was Daniel Ellsberg, the man who released the Pentagon Papers to the New York Times . Ellsberg was high on Nixon's list of enemies and he vowed to destroy him at all costs. In Wild Man, Tom Wells explores the life of Daniel Ellsberg to discover what makes an individual enact the most severe breach of government security ever to occur in the United States. As Wells follows Ellsberg from his early days as a piano prodigy to his years of great promise at Harvard, we see the development of a volatile, narcissistic loner with a voracious sexual appetite, a highly developed intelligence and, most importantly, the overwhelming need to take centre stage in the pageant known as America. In Wild Man, Tom Wells creates an unforgettable picture of Daniel Ellsberg, an American Everyman for the seventies who embodied the promise and paranoia of that uncertain time. This is a thrilling piece of biography that will stand as one of the great American portraits.
Rapid and Global Bridge Assessment for the Military

Prior to any military operation, a critical task of military engineers involves the ability to quickly assess the load-carrying capacity of bridges. These assessments are required to facilitate the selection of movement corridors for troops, equipment, and supplies. Assessments are complicated when bridges are located in areas that are inaccesible or where information regarding design standards is unobtainable. The U.S. Army Engineer Research and Development Center has developed a systematic methodology to provide rapid, accurate bridge assessments on a large scale and in all regions. The methodology uses a machine learning approach designed to discover regional construction and condition tendencies given a sample of onsite inspections. Learning occurs based on the notion of bridge similarity. This approach allows for the completion of bridge assessments in a timely and effective manner. A brief description of the systematic methodology is provided, and the results and analysis of this approach are presen...
Fine structural observations of the erythrocytic stages of Plasmodium chabaudi Landau, 1965.

SYNOPSIS. Electron microscopic examination of Plasmodium chabaudi in mouse erythrocytes revealed many characteristics resembling those observed in other mammalian malarial parasites. A double unit membrane surrounds the trophozoite cytoplasm which contains many ribonucleoprotein particles, a limited amount of endoplasmic reticulum and membraned organelles including sausage-shaped vacuoles and multilaminated membraned bodies. More or less circular double membraned vacuoles, possibly cross sections of the sausage-shaped vacuoles, are common. Typical protozoan mitochondria are lacking. The limiting membrane of the merozoites is triple-layered. Paired organelles and small dense bodies are found in the merozoites along with dense granular masses in the nuclei. Trophozoites have cytostomal structures as well as invaginations of the plasma membrane at sites where no cytostomes are evident. Digestion appears to occur in single membrane-bound vesicles which contain one to several pigment grains. P. chabaudi frequently contains multiple food vacuoles and has polymorphism manifested in part by the presence of cytoplasmic extensions and of nuclei with a variety of shapes. Several apparently free forms are noted, often accompanied by a thin rim of host cytoplasm. “Applique” forms are common among the trophozoites as are forms in which 2 or more trophozoites are joined together. Finally, alterations in the host cytoplasm resembling the socalled Maurer's clefts are frequent. Ferritin-containing vacuoles also appear in the host cell.
Age-related decline in ubiquitin conjugation in response to oxidative stress in the lens

Accumulation of damaged proteins is a major age-related change in lenses of virtually all species and is associated with lens opacification. Proteolytic removal of the damaged proteins may play an important role in maintaining the transparency of the lens. In many tissues, selective removal of abnormal or damaged proteins occurs via a ubiquitin-dependent proteolytic pathway. Ubiquitin, an 8.5 kDa polypeptide, selectively binds to proteins to form ubiquitin-protein conjugates. This ubiquitin-protein conjugate is, in most cases, a signal for protein degradation. In this work, age-related changes in rat lens in the following aspects were detected: (a) levels of the ubiquitin-protein conjugates, (b) some of the enzymes involved in ubiquitin conjugation in rat lenses, and (c) ability to respond to oxidative damage. Endogenous ubiquitin-protein conjugates were detected in epithelium, cortex and nucleus of lenses from young and old rats. The levels of endogenous high molecular weight (HMW) ubiquitin-protein conjugates in each developmental zone of the lenses from young rats were higher than that in the counterparts of lenses from old animals. Peroxide-treatment generally resulted in elevated levels of endogenous HMW ubiquitin-protein conjugates although masses of bulk proteins remain unchanged. The increases in ubiquitin-protein conjugates in the epithelial sections of young and old lenses upon oxidative stress were comparable. In the cortex of young lenses, there was a significant oxidation-related increase in ubiquitin-protein conjugates. There was a similar trend but diminished response in the cortex of old lenses. Nuclear fibers from young lenses also showed an oxidation-induced increase in the level of ubiquitin-protein conjugates. This response was not observed in nuclear fibers of old lenses. The ability to form HMW-ubiquitin conjugates with exogenous 125I-labeled ubiquitin in the lens also increased upon oxidative stress. The extent of the increase in the de-novo ubiquitin conjugating activity upon exposure to oxidation in old lens was much smaller than in young lens. Ubiquitin-activating enzyme (E1), and ubiquitin conjugating enzymes (E2(17k), E2(20k) and E2(25k) were detected by thiol ester assays or Western blot analysis. No significant age-related changes in the levels of E1, E2(17k), E2(20k) and E2(25k) were detected. The activity of E1 and E2(17k) increased upon exposure to H2O2. These data indicate that lens has the ability to increase ubiquitin conjugation activity in response to oxidative stress and this ability is attenuated upon aging. The age-related decrease in the ability to mount a ubiquitin-dependent response upon oxidation may contribute to the accumulation of damaged proteins in the old lenses.
Formulations of the capacity planning problem considering manufacturing flexibility

This paper addresses the problem of determining the capacity requirements for a manufacturing system that consists of versatile metal removing machines, each of which may be configured to perform several different operations at varying levels of efficiency and cost. The number of each machine type required and the assignment of each machine type to different processes are determined by minimizing the sum of machine amortization costs and operating costs. Alternative formulations are presented to address non-splitting of a batch and non-splitting of the processing of a part. The formulations are illustrated using numerical examples.
Two Dimensional Finite Element Modeling to Identify Physiological Bases for Tactile Gap Discrimination

Tactile edge and gap detection are fundamental to performing manual tasks. Because slowly adapting type I (SA-I) mechanoreceptors encode details pertinent to edge localization, understanding low-level encoding is critical to understanding edge perception. Solid mechanics models may help us understand how mechanoreceptors in the skin encode applied surface indentation into neural signals representing edges. Finite element models test whether an indenter separated by a gap creates unique stress/strain distributions in models based upon orientation to fingerprint lines. Results indicate that a gap axis parallel to ridge lines elicits a more pronounced signal than a gap axis perpendicular to ridge lines. The differences may be due to underlying intermediate ridge microstructure. The percentage differences for three derived stress metrics range from 30-87% greater when the indenter's gap axis parallels the ridges. This initial effort demonstrates that underlying skin microstructure may aid tactile perception o...
Reappraisal of guidelines for management of neonates with suspected early-onset sepsis.

Since 1992, professional societies or public health agencies in the United States1–12 and elsewhere13–17 have issued several generations of recommendations for prevention or management of early-onset neonatal sepsis (EOS). Despite those efforts, recommendations remain inconsistent, clarifications are necessary18, local adaptations are common19, and compliance rates are low20. We postulate that lack of consensus, especially regarding postnatal management of the neonate, is largely a result of two sets of factors. First, obstetrical prevention strategies have substantially reduced incidence of EOS, potentially changing the utility of predictive strategies based on risk factors. Second, recent data better delineate relationships among risk factors, clinical signs, and EOS, suggesting that risk predictors may have different utilities in different groups. The purpose of this commentary is to explore these questions and to suggest new approaches to management of newborns who may be at risk for EOS.
EMPHASIZING CONFORMAL AVOIDANCE VERSUS TARGET DEFINITION FOR IMRT PLANNING IN HEAD-AND-NECK CANCER

Purpose To describe a method for streamlining the process of elective nodal volume definition for head-and-neck (H&N) intensity-modulated radiotherapy (IMRT) planning. Methods and Materials A total of 20 patients who had undergone curative-intent RT for H&N cancer underwent comprehensive treatment planning using three distinct, plan design techniques: conventional three-field design, target-defined IMRT (TD-IMRT), and conformal avoidance IMRT (CA-IMRT). For each patient, the conventional three-field design was created first, thereby providing the “outermost boundaries” for subsequent IMRT design. In brief, TD-IMRT involved physician contouring of the gross tumor volume, high- and low-risk clinical target volume, and normal tissue avoidance structures on consecutive 1.25-mm computed tomography images. CA-IMRT involved physician contouring of the gross tumor volume and normal tissue avoidance structures only. The overall physician time for each approach was monitored, and the resultant plans were rigorously compared. Results The average physician working time for the design of the respective H&N treatment contours was 0.3 hour for the conventional three-field design plan, 2.7 hours for TD-IMRT, and 0.9 hour for CA-IMRT. Dosimetric analysis confirmed that the largest volume of tissue treated to an intermediate (50 Gy) and high (70 Gy) dose occurred with the conventional three-field design followed by CA-IMRT and then TD-IMRT. However, for the two IMRT approaches, comparable results were found in terms of salivary gland and spinal cord protection. Conclusion CA-IMRT for H&N treatment offers an alternative to TD-IMRT. The overall time for physician contouring was substantially reduced (approximately threefold), yielding a more standardized elective nodal volume. Because of the complexity of H&N IMRT target design, CA-IMRT might ultimately prove a safer and more reliable method to export to general radiation oncology practitioners, particularly those with limited H&N caseload experience.
Separate, causal roles of the caudate in saccadic choice and execution in a perceptual decision task

In contrast to the well-established roles of the striatum in movement generation and value-based decisions, its contributions to perceptual decisions lack direct experimental support. Here, we show that electrical microstimulation in the monkey caudate nucleus influences both choice and saccade response time on a visual motion discrimination task. Within a drift-diffusion framework, these effects consist of two components. The perceptual component biases choices toward ipsilateral targets, away from the neurons' predominantly contralateral response fields. The choice bias is consistent with a nonzero starting value of the diffusion process, which increases and decreases decision times for contralateral and ipsilateral choices, respectively. The nonperceptual component decreases and increases nondecision times toward contralateral and ipsilateral targets, respectively, consistent with the caudate's role in saccade generation. The results imply a causal role for the caudate in perceptual decisions used to select saccades that may be distinct from its role in executing those saccades.
Drug biotransformation interactions in man. II. A pharmacokinetic study of the simultaneous conjugation of benzoic and salicylic acids with glycine.

The major route of biotransformation of benzoic acid and salicylic acid in man is conjugation with glycine, resulting in the formation of hippuric acid and salicyluric acid, respectively. Both processes are capacity-limited in the usual dose range and approach a maximum rate following administration of sufficiently high doses of precursor. The rate of hippuric acid formation after oral administration of 5 g. benzoic acid in solution is increased markedly by the concomitant administration of glycine. In contrast, the administration of glycine has no effect on the formation of salicyluric acid. Salicylic acid in doses of 1 to 3 g. given orally 2 or 3 hr. prior to 2.0 to 5.0 g. benzoic acid had no measurable effect on the formation of hippuric acid. However, benzoic acid has a pronounced inhibitory effect on the formation of salicyluric acid from salicylic acid. This effect was not prevented by the co-administration of glycine. These results indicate that in man the availability of glycine is rate-limiting in the formation of hippuric acid, but not in the formation of salicyluric acid. Apparently, the inhibitory effect of benzoic acid on the formation of salicyluric acid is not due to competition for glycine but involves another phase in the biotransformation process.
Factors affecting pre-arbitral settlement of rights disputes: Predicting the method of rights dispute resolution

Every arbitrator has had a scheduled arbitration hearing cancelled because the disputants have privately resolved the matter. This article identifies and examines those characteristics of grievance impasses that are associated with pre-arbitral dispute settlement — that is, settlement of a grievance dispute after submission to arbitration but before an award is issued — and those that are associated with arbitral dispute settlement — that is, settlement of a grievance dispute through issuance of an arbitration award. The study concludes that the primary determinant of pre-arbitral settlement is the degree of private, outside, legal representation.
Fostering biliteracy in a monolingual milieu: Reflections on two counter-hegemonic English immersion classes:

This article presents data from two yearlong ethnographic studies of the biliteracy instruction and development of young Latina/o children in two counter-hegemonic English immersion classes in the ...
Teaching about the risks of electronic voting technology

In these interesting times computer scientists are increasingly called upon to help concerned citizens understand the risks involved in the current generation of electronic voting machines. These risks and the concurrent escalation of legal challenges to the election system in the United States have shaken the confidence of many Americans that a fair and accurate election is even possible. As computer science educators we have an opportunity to add breadth and depth to our curriculum by using these issues to show how existing concepts can be applied to new problems, and how new problems extend our field. In this paper we identify some of the main problems with e-voting machines and vote-counting technology and suggest ways that discussions of the risks and the attendant societal and ethical issues might be incorporated into the computer science curriculum.
Ethnic differences in quality of life in insured older adults with diabetes mellitus in an integrated delivery system.

Objectives: To explore racial and ethnic (ethnic hereafter) differences in health-related quality of life (HRQL) in older adults with diabetes mellitus in an integrated delivery system. Design: Observational cross-sectional study. Setting: Kaiser Permanente Northern California. Participants: Ethnic-stratified, random sample of 6,096 adults with diabetes mellitus aged 60 to 75 who completed a HRQL questionnaire. Measurements: Physical and mental HRQL were measured based on the Medical Outcomes Study 8-item Short Form Survey (range 0�100, mean 50). Age- and sex-adjusted weighted linear regression models estimated associations between ethnicity and HRQL and evaluated potential mediators (socioeconomic status, acculturation, health behaviors, diabetes mellitus�related conditions). Differences in ethnic-specific, adjusted mean HRQL scores were tested (reference whites). Results: Physical HRQL was better for Filipinos (48.3, 95% confidence interval (CI) = 47.0�49.6, P < .001), Asians (48.1, 95% CI = 46.8�49.3, P < .001), Hispanics (45.1, 95% CI = 44.2�46.0, P < .001), and blacks (44.2, 95% CI = 43.3�45.1, P = .04) than whites (42.9, 95% CI = 42.6�43.2). Adjusting for potential mediators did not change these relationships. Mental HRQL was better only for Asians (52.7, 95% CI = 51.6�53.7, P = .01) than for whites (51.0, 95% CI = 50.7�51.3), but this difference was small and became nonsignificant after adjustment for socioeconomic status, acculturation, health behaviors, and diabetes mellitus�related conditions. Conclusion: In older adults with diabetes mellitus in a well-established integrated healthcare delivery system, ethnic minorities had better physical HRQL than whites. Equal access to care in an integrated delivery system may hold promise for reducing health disparities in diabetes mellitus-related patient-reported outcomes.
Dimensional weights and forage of Barclay willow and sweetgale on moose ranges in the wetlands of the Copper River Delta, Alaska

Abstract Above-ground shoots of Barclay willow ( Salix barclayi ) and sweetgale ( Myrica gale var. tomentosa ) from shrub-swamp on the wetlands of the Copper River Delta, Alaska, were harvested at the early-growth, full-growth, and early-dormancy stages of growth. Seven dimensional measurements (vertical height, basal stem diameter, upper stem diameter, basal stem length, crown depth, maximum crown diameter, second crown diameter) were made on each above-ground shoot before harvest. The cross-sectional area of the crown was calculated from crown diameters and also used as a non-destructive measurement. Each shoot was sorted into four individual (basal stem, branch, terminal twig, leaf) and two combined (crown wood, total above-ground) dimensional weight categories and the oven-dry weights of each category determined. Measurements were used as independent variables in forward, stepwise multiple regression to develop a ‘best model’ estimator of mean dimensional weight at each growth stage. The ability of the regression models to accurately predict mean dimensional weight at each growth stage was tested on an independent sample of above-ground shoots of both shrubs. The early-dormancy regression model predicted mean weights of basal stem, twig and total above-ground dimensional weights of Barclay willow within 1% of actual weights. The full-growth regression model gave the most accurate predictions of the mean dimensional weights of crown wood, branch and leaf of Barclay willow. The early-dormancy regression model provided the closest estimates of the mean weights of basal stem and crown wood of sweetgale. Total above-ground shoot and branch mean weights were best estimated by the regression model for the full-growth period. Neither regression model gave accurate estimates of the mean weights of sweetgale twigs and leaves. Digestibility, nutrient status and energy content of the material in each dimensional category were determined at each growth period.
Prompt lepton production in upsilon and t -quarkonium decays

We have calculated the lepton-energy distributions and invariant-mass-squared distributions for the decay of upsilon and t-quarkonium mesons into leptons +X via either c or b quarks as on-shell intermediate states. We also predict the branching ratios for those decays.
A New Species of Seabrookia (Foraminiferida) from the Later Tertiary of Southern California

SYNOPSIS. Published records of the foraminiferal genus Seabrookia indicate the genus to be widespread and its occurrence apparently discontinuous. The genus is here reported for the first time as a fossil from the eastern Pacific Ocean region, with the description of the new species S. cooperta from the California Miocene.
Ethnic and religious differentials in Bulgarian mortality, 1993-98.

We investigated ethnic/religious mortality differentials in Bulgaria during the 1990s. The analyses employed a unique longitudinal data-set covering the entire population of Bulgaria from the census of 1992 until 1998. The mortality of Roma is very high compared to all other ethnic/religious groups. The excess applies to nearly every cause of death examined and is not entirely explained by the adverse location of Roma on social and economic variables. For young men, Muslim mortality is substantially lower than that of non-Muslims when socio-economic differences are controlled. An analysis of causes of death suggests that lower consumption of alcohol may contribute to this ‘Muslim paradox’. For older Turkish women, a significant mortality disadvantage remains after controls are imposed. Suicide mortality is lower for Muslims than for Christian groups of the same ethnicity. Consistent with deteriorating economic conditions over the study period, mortality was rising, particularly for women.
α1 Adrenergic Agonist Induction of p21 waf1/cip1 mRNA Stability in Transfected HepG2 Cells Correlates with the Increased Binding of an AU-rich Element Binding Factor

Stimulation of transfected HepG2 cells (TFG2) with the alpha(1)-adrenergic agonist phenylephrine (PE) significantly activated p21(waf1/cip1) gene expression without affecting p53 gene expression. Northern blotting and reporter assay demonstrated that this induction was due to PE stimulation of p21(waf1/cip1) mRNA stability. To further define the underlying mechanism, we prepared a chloramphenicol acetyltransferase (CAT)-p21(waf1/cip1) 3'-untranslated region (3'-UTR) hybrid construct by inserting the 3'-UTR of p21(waf1/cip1) mRNA just downstream from the CAT coding sequence and transfected it into TFG2 cells. PE treatment enhanced the activity of this construct by 6-fold. Deletion analyses indicated that an AU-rich element (AURE) located between 553 to 625 within the p21(waf1/cip1) 3'-UTR was required for this induction. RNA gel shift assays demonstrated that this AURE bound an RNA-binding protein. This protein has been purified 5000-fold from PE-treated TFG2 cells by heparin-Sepharose and RNA affinity chromatography. SDS-polyacrylamide gel electrophoresis, UV cross-linking, and Northwestern analyses indicated the molecular mass of this protein as 24 and 52 kDa. Finally, PE treatment markedly enhanced this RNA-protein binding by a p42/44 mitogen-activated protein kinase-dependent mechanism. These data suggest that the AURE located between 553 and 625 within the p21(waf1/cip1) mRNA 3'-UTR, which binds an RNA-binding protein, is responsible for PE-induced p21(waf1/cip1) mRNA stability.
Statistical Postprocessing of NOGAPS Tropical Cyclone Track Forecasts

Abstract A statistical postprocessing technique is developed and tested to reduce the U.S. Navy global model (NOGAPS) track forecast errors for a sample of western North Pacific tropical cyclones during 1992–96. The key piece of information is the offset of the initial NOGAPS position relative to an updated (here best-track) position that will be known by 6 h after the synoptic times, which is when the NOGAPS forecast is actually available for use by the forecaster. In addition to the basic storm characteristics, the set of 24 predictors includes various segments in the 0–36-h NOGAPS forecast track as well as a 0–36-h backward extrapolation that is compared with the known recent track positions. As statistically significant regressions are only found for 12–36 h, the original 36-h to 72-h NOGAPS track segment is simply translated to the adjusted 36-h position. For the development sample, the adjusted NOGAPS track errors are reduced by about 51 n mi (95 km) at 12 h, 35 n mi (65 km) at 36 h, and 28 n mi (52...
Expression time for benzo[a]pyrene-induced 6-thioguanine-resistant mutations in V79 Chinese hamster cells.

Abstract The effect of expression time (the time between the end of the treatment period and the first exposure to selective medium) on the frequency of benzo[ a ]pyrene(BP)-induced mutations at the HGPRT (hypoxanthine-guanine phosphoribosyl transferase 2.4.2.8) locus was examined in the cell-mediated mutation assay in which V79 Chinese hamster cells are the targets and BP activation is mediated by Syrian hamster embryo cells. After the optimal expression time (4–5 days), the mutation frequency induced by exposure to 0.5 μg BP/ml decreased logarithmically with increasing lenght of expression time until at 40 days there was a complete absence of mutant cells. The growth rates of three BP-induced 6-thioguanine-resistant clones were examined; each of these clones had a 30% longer lag time before reaching the period of logarithmic growth than the parent V79 cells. This suggests that the decay in mutation frequency with increasing expression time may be due to the slower reinitiation of growth by mutant than non-mutant cells after subcultivation into non-selective medium; this results in a loss of 25–40% of the mutant cells with each subculture. These findings show that optimal expression time in cell-mediated mutation assays may be of short duration and that this must be taken into account in the design and interpretation of such assays.
Computational definition of a mixed valent Fe(II)Fe(I) model of the [FeFe]hydrogenase active site resting state.

Abstract Density-functional calculations have been used to examine the electronic structure and bonding in the recently reported complex [(PMe 3 )(CO) 2 Fe(μ-pdt)(μ-CO)Fe(CO)(IMes)] + ( 1 + , IMes = 1,3-bis(2,4,6-trimethylphenyl)-imidazol-2-ylidene). This mixed valent Fe II Fe I complex features a rotated geometry that places a carbonyl ligand in a semi-bridging position, which makes it an accurate model of the S = ½ resting state of the [FeFe]-hydrogenase active site. Calculations indicate that the unpaired electron in this complex lies almost entirely on the rotated iron center, implying that this iron remains in the Fe I oxidation state, while the unrotated iron has been oxidized to Fe II . The frontier molecular orbitals in 1 + are compared with those in the neutral Fe I Fe I precursor (PMe 3 )(CO) 2 Fe(μ-pdt)(μ-CO)Fe(CO)(IMes) at both its optimized geometry ( 1 ) and constrained to a rotated geometry ( 1 rot ). These theoretical results are used to address the role of the bridging CO ligand in 1 + and to predict reactivity patterns; they are related back to the intricate biological mechanism of [FeFe]-hydrogenase.
Stress generation during high-temperature oxidation of metallic alloys

During high-temperature oxidation, constraint stresses are generated in the growing oxide in response to a lateral growth strain mechanism. Substantial progress has been made in recent years in clarifying the mechanisms of oxide growth that sets the stage for understanding the origin of the lateral growth strain. Nevertheless, identification of the lateral growth mechanisms remains elusive.
Hyperglycemia promotes tissue plasminogen activator-induced hemorrhage by Increasing superoxide production.

Objective: Risk of intracerebral hemorrhage is the primary factor limiting use of tissue plasminogen activator (tPA) for stroke. Clinical studies have established an association between admission hyperglycemia and the risk of hemorrhage with tPA use, independent of prior diabetes. Here we used an animal model of tPA-induced reperfusion hemorrhage to determine if this clinical association reflects a true causal relationship. Methods: Rats underwent 90 minutes of focal ischemia, and tPA infusion was begun 10 minutes prior to vessel reperfusion. Glucose was administered during ischemia to generate blood levels ranging from 5.9 ± 1.8mM (normoglycemia) to 21 ± 2.3mM. In some studies, apocynin was administered to block superoxide production by nicotinamide adenine dinucleotide phosphate (NADPH). Brains were harvested 1 hour or 3 days after reperfusion to evaluate the effects of hyperglycemia and apocynin on oxidative stress, blood–brain barrier breakdown, infarct volume, and hemorrhage volume. Results: Rats that were hyperglycemic during tPA infusion had diffusely increased blood–brain barrier permeability in the postischemic territory, and a 3- to 5-fold increase in intracerebral hemorrhage volumes. The hyperglycemic rats also showed increased superoxide formation in the brain parenchyma and vasculature during reperfusion. The effects of hyperglycemia on superoxide production, blood–brain barrier disruption, infarct size, and hemorrhage were all attenuated by apocynin. Interpretation: These findings demonstrate a causal relationship between hyperglycemia and hemorrhage in an animal model of tPA stroke treatment, and suggest that this effect of hyperglycemia is mediated through an increase in superoxide production by NADPH oxidase. ANN NEUROL 2011
Torque Oscillations of Synchronous Motors Under Starting Conditions

Salient-pole synchronous motors develop an average torque and a twice-slip frequency oscillating torque during starting. If coupled to a complex mechanical system, with resonance in the oscillatory frequency range, severe stresses may result in shafts, gears, and couplings. The objective of the paper is to develop motor and mechanical system models, which can lead to the analysis of the torsional response of the motor load, and to avoid the use of specific motors that yield excessive values of stress or take steps to mitigate the oscillation magnitudes. The effect of the field discharge resistance was investigated.
Distinct contribution of protein kinase Cδ and protein kinase Cε in the lifespan and immune response of human blood monocyte subpopulations.

Monocytes, key components of the immune system, are a heterogeneous population comprised of classical monocytes (CD16(-) ) and non-classical monocytes (CD16(+) ). Monocytes are short lived and undergo spontaneous apoptosis, unless stimulated. Dysregulation of monocyte numbers contribute to the pathophysiology of inflammatory diseases, yet the contribution of each subset remains poorly characterized. Protein kinase C (PKC) family members are central to monocyte biology; however, their role in regulating lifespan and immune function of CD16(-) and CD16(+) monocytes has not been studied. Here, we evaluated the contribution of PKCδ and PKCe in the lifespan and immune response of both monocyte subsets. We showed that CD16(+) monocytes are more susceptible to spontaneous apoptosis because of the increased caspase-3, -8 and -9 activities accompanied by higher kinase activity of PKCδ. Silencing of PKCδ reduced apoptosis in both CD16(+) and CD16(-) monocytes. CD16(+) monocytes express significantly higher levels of PKCe and produce more tumour necrosis factor-α in CD16(+) compared with CD16(-) monocytes. Silencing of PKCe affected the survival and tumour necrosis factor-α production. These findings demonstrate a complex network with similar topography, yet unique regulatory characteristics controlling lifespan and immune response in each monocyte subset, helping define subset-specific coordination programmes controlling monocyte function.
Scattering and diffraction of plane P waves by circular cylindrical canyons with variable depth-to-width ratio

The scattering and diffraction of plane (P) waves by a circular canyon with variable width-to-depth ratio has been studied in this paper. Series of Bessel function expansions have been used to solve the problem. To illustrate the results, the surface displacement amplitudes and phases are presented. The following parameters are found to affect the results: 1. The angle of incidence, θα. 2. The ratio of the canyon depth to canyon width, h/a, 3. The dimensionless frequency of the incident P wave, η and 4. The Poisson's ratio, ν. The displacement amplitudes and phases on the ground surface show significant deviation from those of the uniform half-space motions, especially at high frequencies, when the wavelengths of the incident and scattered waves are small compared to the size of the canyon.
Symmetric knots and billiard knots

Symmetry of geometrical figures is reflected in regularities of their algebraic invariants. Algebraic regularities are often preserved when the geometrical figure is topologically deformed. The most natural, intuitively simple but mathematically complicated, topological objects are Knots. We present in this papers several examples, both old and new, of regularity of algebraic invariants of knots. Our main invariants are the Jones polynomial (1984) and its generalizations. In the first section, we discuss the concept of a symmetric knot, and give one important example -- a torus knot. In the second section, we give review of the Jones type invariants. In the third section, we gently and precisely develop the periodicity criteria from the Kauffman bracket (ingenious version of the Jones polynomial). In the fourth section, we extend the criteria to skein (Homflypt) and Kauffman polynomials. In the fifth section we describe r^q periodicity criteria using Vassiliev-Gusarov invariants. We also show how the skein method may be used for r^q periodicity criteria for the classical (1928) Alexander polynomial. In the sixth section, we introduce the notion of Lissajous and billiard knots and show how symmetry principles can be applied to these geometric knots. Finally, in the seventh section, we show how symmetry can be used to gain nontrivial information about knots in other 3-manifolds, and how symmetry of 3-manifolds is reflected in manifold invariants. In particular, we find the formula for a torus knot in a solid torus and we show that the third eigenvector (e_3) of the Kauffman bracket skein module of the solid torus (with respect to the meridian Dehn twist) can be realized by a link in a solid torus.
Sleep disturbance in women before myocardial infarction

Abstract Objective The study objective was to describe the prevalence and correlates of sleep disturbances among women who retrospectively reported sleep disturbance before their myocardial infarction (MI). MI is frequently unrecognized in women because they may have only vague symptoms, such as sleep disturbance. Describing correlates of sleep disturbance before MI may assist in recognizing women at risk for coronary heart disease. Methods A secondary analysis was performed of a dataset derived from 15 sites. Results Of 1270 women experiencing initial MI, 632 reported new onset of or worsening sleep disturbance before MI. Prevalence was similar across racial groups. Women reporting prodromal sleep disturbance were more likely to be older, to be heavier, and to report cognitive changes (adjusted odds ratio [OR], 1.47), new or increasing anxiety (adjusted OR, 2.21), and unusual fatigue (adjusted OR, 2.16). Conclusion Subjective reports of sleep disturbance preceding MI seem to be prevalent in women of all races and may be an important warning sign for MI in women.
Compressed and Distributed Sensing of Multivariate Neural Point Processes

This paper proposes a new approach to simultaneously estimate time-varying intensity functions of multiple point processes from their continuous-time signal representation. We use models of neural response properties in the cortex to illustrate the theory of the proposed approach. Based on sparse representation of the continuous-time signals in the context of compression, it is shown that intensity functions can be approximated reasonably well without the need to decompress and classify the source signals. The approach is best suited for the case when multiple point processes are characterized by non-binary spike waveforms observed with an array of sensors. When spike waveforms from different sources are correlated, the estimated intensities can be inaccurate due to spike classification errors. We therefore build on our previous work for separating correlated spike waveforms to enable enhanced separation of those intensity functions. We finally show that this framework leads to substantial savings in computational complexity for real time operation in resource constrained signal processing systems.
Antithrombotic therapy: current practice and future trends.

1. Heparin, LMW Heparin and Related Compounds (Bick) 2. Generic Low-Molecular-Weight Heparins (Fareed) 3. Warfarins other Vitamin K Antagonists: Past, Present and Future (Pineo) 4. Antiplatelet Agents: Current Drugs and Future Trends (Messmore) 5. Direct Thrombin Inhibitors: Current Agents and Future Trends (Frenkel) 6. Thrombolytic Agents (Baker) 7. Catheter-Related Thrombosis: Diagnosis and Management (Kuter) 8. Summary: The Future of Antithrombotic Therapy (Bick)
The Propriocpetive Aftereffects of Prism Adaptation Influence Interlimb Rhythmic Coordination

Adaptation to prisms can produce a change in felt arm position, termed proprioceptive shift. We studied the effects of prism-induced proprioceptive shift on interlimb rhythmic coordination performed under haptic (proprioceptive) guidance, in the absence of vision. Relative to interlimb rhythmic coordination performed before prism exposure, the observed steady states of relative phase for post-exposure coordination were shifted by a small but reliable amount. The shift was in the direction expected given the direction of optical displacement. The amount of variability of interlimb rhythmic coordination was unaffected by prism exposure. The implications of the results apply to virtual environment design.
Scanning Force Microscopy in the Classroom

We describe a strategy to efficiently introduce concepts of scanning force microscopy in introductory science and engineering classes. Particular emphasis is placed in qualitative understanding via intuition building with numerical trial and error. In addition, model development is introduced and used to perform quantitative predictions of force-separation curves.
Bond strength evaluation on dental structures after non-thermal plasma treatment

Summary form only given. This study aims to evaluate the potential of atmospheric pressure non-thermal plasma technology (NPT) to enhance the adhesive bond strength on normative dentin substrates. Two different microplasma jets were used in our experiments, a direct-current driven microhollow cathode discharge jet operated in air and a rf-driven jet operated in Ar. Other gas mixtures, e.g. He/O2 are also being explored.Initial experiments were carried out using fresh, non-carious third molars obtained under a protocol approved by the New York University College of Medicine Institutional Review Board. The occlusal enamel of each tooth was removed perpendicular to the long axis of the tooth to expose a flat dentin surface, which was subsequently polished. The specimens were randomly assigned to 3 groups for bonding and NPT applications. For the control group, three teeth were etched with phosphoric acid etched, the dentin bonding agent (DBA) was applied and the teeth were restored with a 4 mm thick resin composite. Another group of 3 teeth was treated with an Ar plasma and a third group was exposed to an air plasma. For the plasma-treated groups, the dentin substrates were etched for 15 s, rinsed for 10s and treated by the plasma for 20 s followed by DBA application and resin composite placement. All specimens were stored in water for 24 h prior to a microtensile bonding test. Preliminary data indicate that the bond strength values were not significantly affected by the Ar or air plasma treatment. We observed that teeth treated with the Ar plasma exhibited an enhanced premature failure rate (-50%) during the cutting or specimen mounting phases. This was not observed for the control or for the air plasma treated groups. Extensive surface characterization studies using various microscopy techniques, XPS, and micro-Raman are underway to assess the effect of the plasma on the surface. Optical emission spectroscopy is used to monitor the presence of reactive species (eg. OH, O) in the plasma for various operating conditions and feed gases or gas mixtures. The results of these studies will be presented and discussed in detail at the Conference.
Performance analysis of a token-based distributed mutual exclusion protocol

The authors develop a methodology by which an approximation to a polling system model is used to analyze the performance of a simple circulating token mutual exclusion protocol. This protocol is chosen for a first attempt to apply performance measurement to mutual exclusion algorithms primarily because of its simplicity. A simple queueing model for a distributed protocol with a circulating token is presented. The analysis is tractable for arbitrarily large networks, and the results produced seem to be reasonably accurate. >
Hypermethylation of the P15INK4b and P16INK4a in agnogenic myeloid metaplasia (AMM) and AMM in leukaemic transformation

Summary. Hypermethylation of p15 and p16 genes was determined in 32 patients with agnogenic myeloid metaplasia(AMM), also known as idiopathic myelofibrosis (MF). These included 10 patients in leukaemic transformation phase. Using polymerase chain reaction-based methylation analysis assay methods, with substantiation using Southern blot analysis, the study showed no hypermethylation of p15 or p16 genes in the chronic phase of AMM, but p15 gene hypermethylation was found in four patients (40%) and p16 gene hypermethylation in two patients (20%) when they were in leukaemic transformation stage. Furthermore, two of the patients in leukaemic transformation were found to have both p15 and p16 gene hypermethylation, demonstrating possible multiple gene hypermethylation in the same patient. Thus, hypomethylation agents for treating patients with AMM in leukaemic transformation may be appropriate for future trials.