cssi/SciSciGPT-SciSciNet huggingface dataset:
Modification of the Expression of Adenosine 3',5'-Cyclic Monophosphate-Induced Differentiated Functions in Neuroblastoma Cells by Beta-Carotene and D-Alpha-Tocopheryl Succinate

The role of beta-carotene and vitamin E in modifying the effect of cell differentiating agent has not been studied. This study has investigated the effects of beta-carotene and d-alpha-tocopheryl succinate (alpha-TS) on adenosine 3′,5′-cyclic monophosphate (cAMP) induced differentiated functions in murine neuroblastoma cells (NBP2) in culture.Prostaglandin E1 (PGE1), a stimulator of adenylate cyclase, and 4-(3-butoxy-4-methoxy-benzyl)-2-imidazolidinone (R020-1724), an inhibitor of cyclic nucleotide phosphodiesterase, were used to induce differentiation in NB cells.Both beta-carotene and alpha-TS markedly enhanced the level of morphologic differentiation (neurite formation) induced by both PGE1 and R020-1724. However, beta-carotene and alpha-TS by themselves were ineffective. These vitamins increased tyrosine hydroxylase (TH) activity. However, beta-carotene did not significantly affect PGE1- and R020-1724-stimulated rise in TH activity. alpha-TS at a higher concentration inhibited PGE1- and R020-1724-stim...
Multiple manifestations of X‐ray–induced genomic instability in Chinese hamster ovary (CHO) cells

Carcinogenesis is postulated to follow a multistep cascade in which the first genetic event may destabilize cells and thereby facilitate the induction of subsequent mutations within the same cell. It has recently been shown that exposure to ionizing radiation can in itself induce a persistent, heritable genetic instability in cells. To further investigate this phenomenon, we utilized a mutationally unstable population derived from a single Chinese hamster ovary (CHO) cell that survived X irradiation. We exposed these cells to a second dose of radiation, selected hypoxanthine phosphoribosyl transferase (HPRT) mutant subclones, and identified the type of mutations involved. We found complete deletions, continuous tract partial deletions, single-exon deletions, discontinuous-exon deletions (“skip mutations”), and point mutations (changes of less than 100 bp) among the isolated HPRT mutants. We hypothesized that the skip mutation clones might be more likely to demonstrate genomic instability. To test this hypothesis, mutant subclones were screened for three markers of genetic instability: alteration of minisatellite sequences, change in telomere length, and induction of chromosomal aberrations. Clones with skip mutations and single-exon deletions possessed elevated frequencies of minisatellite alterations and chromosomal aberrations, particularly rings and dicentrics. All mutant clones showed longer telomere terminal restriction fragment lengths than did wild-type cells. These results are consistent with the hypothesis that irradiation may induce a global instability phenotype, since the multiple alterations observed are mechanistically distinct, heritable cellular modifications that arose in the clonogenic progeny of the irradiated cells. Skip mutations may be one manifestation of this instability, but their presence was not specifically associated with the other genetic alterations. © 2001 Wiley-Liss, Inc.
Reprint of “Do Housing Choice Voucher Holders Live Near Good Schools?” ☆

Abstract The Housing Choice Voucher program was created, in part, to help low income households reach a broader range of neighborhoods and schools. Rather than concentrating low income households in designated developments, vouchers allow families to choose their housing units and neighborhoods. In this project we explore whether low income households use the flexibility provided by vouchers to reach neighborhoods with high performing schools. Unlike previous experimental work, which has focused on a small sample of voucher holders constrained to live in low-poverty neighborhoods, we look at the voucher population as a whole and explore the broad range of neighborhoods in which they live. Relying on internal data from HUD on the location of assisted households, we link each voucher holder in the country to the closest elementary school within their school district. We compare the characteristics of the schools that voucher holders are likely to attend to the characteristics of those accessible to other households receiving place based housing subsidies, other similar unsubsidized households and fair market rent units within the same state and metropolitan area. These comparisons provide us with a portrait of the schools that children might have attended absent HUD assistance. In comparison to other poor households in the same metropolitan areas, we find that the schools near voucher holders have lower performing students than the schools near other poor households without a housing subsidy. We probe this surprising finding by exploring whether differences between the demographic characteristics of voucher holders and other poor households explain the differences in the characteristics of nearby schools, and whether school characteristics vary with length of time in the voucher program. We also examine variation across metropolitan areas in the relative quality of schools near to voucher holders and whether this variation is explained by economic, socio-demographic or policy differences across cities.
Markup Bid Pricing for Net Worth Maximisation and Target Profits

Essentially there are three types of competitive bids or price quotes: fixed price bids, cost‐plus markup bids, and incentive (risk‐sharing) bids. An “Expected Present Value” (EPV) model of competitive bidding is presented which establishes the requirements for the maximisation of the firm's expected present value of net worth. Reconciliation of the EPVC and the markup procedure allows an examination of the issues that must be considered in order that the firm's bid prices and quotes best serve the objective of net worth maximisation when information search costs are expected to be prohibitive. Observations suggest that firms do not attempt to maximise their net worth, preferring instead to pursue target rates of capacity utilisation and profitability. Therefore the EPVC model does not explain or predict the behaviour of all bidding firms. A behavioural model is suggested, based on the positive starting point of business practice. This enables firms to do what they do better. Based on what they already do, it holds few surprises or complexities and requires little information on complex issues and so obviates the need for substantial expenditure on search costs.
Thin-shell magnetohydrodynamic equations for the solar tachocline

We present a new system of equations designed to study global-scale dynamics in the stably-stratified portion of the solar tachocline. This system is derived from the 3D equations of magnetohydrodynamics in a rotating spherical shell under the assumption that the shell is thin and stably-stratified (subadiabatic). The resulting thin-shell model can be regarded as a magnetic generalization of the hydrostatic primitive equations often used in meteorology. It is simpler in form than the more general anelastic or Boussinesq equations, making it more amenable to analysis and interpretation and more computationally efficient. However, the thin-shell system is still three-dimensional and as such represents an important extension to previous 2D and shallow-water approaches. In this paper we derive the governing equations for our thin-shell model and discuss its underlying assumptions, its context relative to other models, and its application to the solar tachocline. We also demonstrate that the dissipationless thin-shell system conserves energy, angular momentum and magnetic helicity.
Polarization isolation limit for dual-polarized phased array systems

Polarization isolation in dual polarized phased arrays is studied as an expansion of the unit cell behavior. It concludes that a fundamental polarization isolation limit exists in the diagonal far-field planes, while the principal planes exhibit no polarization limit. The diagonal plane polarization isolation limit is scan dependent, reaching a 0 dB maximum at 90°, or end-fire scan. While aperture design features may approach this limit, and manufacturing tolerances modulate it, it apparently is not exceeded in phased array test results. Polarization compensation circuits may improve on the aperture polarization isolation, but are also fundamentally limited by it.
p -competition numbers

Abstract If D = ( V , A >) is a digraph, its p -competition graph has vertex set V and an edge between x and y if and only if there are distinct vertices a 1 ,…, a p in D with ( x, a i ) and ( y,a i ) arcs of D for each i ⩽ p . The p -competition number of a graph is the smallest number of isolated vertices which need to be added in order to make it a p -competition graph. These notions generalize the widely studied p = 1 case, where they correspond to ordinary competition graphs and competition numbers. We obtain bounds on the p -competition number in terms of the ordinary competition number, and show that, surprisingly, the p -competition number can be arbitrarily smaller than the ordinary competition number.
Novel technique to separate systematic and random defects during 65nm and 45nm process development

Defect inspections performed in R&D may often result in 100k to 1M defect counts on a single wafer. Such defect data combine systematic and random defects that may be yield limiting or just nuisance defects. It is difficult to identify systematic defects from defect wafer map by traditional defect classification where random sample of 50 to 100 defects are reviewed on review SEM. Missing important systematic defect types by traditional sampling technique can be very costly in device introduction. Being able to efficiently sample defects for SEM review is not only challenging, but can result in a Pareto that lacks in usefulness for R& D and for yield improvement. To mitigate the issue and to reduce yield improvement cycle in advanced technology, a novel method has been proposed. Instead of using random sampling method, we have applied a pattern search engine to correlate defect of interest (DOI) to its pattern background. Based on the approach we have identified an important defect type, STI cave defect, to be the major defect type on defect Pareto. For the defect type, stack die map was generated that indicated a distinctive signature. The result was compared against design layout to confirm that the defects were occurring at certain locations of design layout. Afterwards the defect types were reviewed using SEM and in-line FIB for further confirmation. We have found the cause of this void defect type to be poor gap-fill in deposition step. Based on the novel technique, we were able to filter out a systematic defect type quickly and efficiently from wafer map that consist of random and systematic defects.
STRA6, a Cell-Surface Receptor for Retinol-Binding Protein: The Plot Thickens

How retinol (vitamin A) is taken up by cells has been an area of active research since the first report of a cell-surface receptor for retinol-binding protein (RBP) in the mid-1970s. Two recent reports, by Kawaguchi et al. (2007) and Pasutto et al. (2007), provide compelling data regarding the molecular identity and properties of a RBP receptor and open new research avenues for a better understanding of retinoid biology.
Water Quality in Walnut Creek Watershed: Herbicides and Nitrate in Surface Waters

There is a lack of quantitative information describing the impact of farming on water quality at the watershed scale. This study documents the surface water quality of Walnut Creek-a 5130-ha watershed with about 86% of the land used for crop production. Starting in 1990, flow and concentrations of NO 3 -N and four herbicides-atrazine [6-chloro-N-ethyl-N'-(1-methylethyl)-1,3,5-triazine-2,4-diamine], alachlor [2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl)acetamide], metribuzin [4-amino-6-(1, 1-dimethylethyl)-3-(methylthio)-1,2,4-triazin-5(4H)-on ], and metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-methoxy-1-methylethyl)acetamide] were measured at eight locations. Nitrate-N concentrations often exceeded 10 mg L -1 during May, June, and July. Total losses from the watershed ranged from 4 to 66 kg ha -1 yr -1 and represented 6 to 115% of the N applied as fertilizer in any year. Atrazine and metolachlor were detected at concentrations >0.2 μg L -1 in about half of all water samples, while alachlor and metribuzin were seldom detected. Median concentrations for atrazine and metolachlor were below 1 μg L -1 for all locations within the watershed. During runoff events, herbicide concentrations in the stream increased while NO 3 -N concentrations decreased. Yearly losses from the watershed ranged from 0.2 to 7.5 g ha -1 for atrazine and from 0.3 to 6.7 g ha -1 for metolachlor. These losses represent 0.18 to 5.6% of the atrazine and 0.047 to 1.6% of the metolachlor applied in any year.
Pathophysiologic and pharmacotherapy considerations in the management of the black hypertensive patient.

Abstract The mortality and morbidity of hypertension-related diseases among blacks are much higher than in age- and sex-matched white counterparts. New data show that the incidence of renal damage may be 18 to 20 times greater in blacks than in whites. Some preliminary data also indicate that coronary heart disease is much more prevalent in blacks than previously suspected and that coronary heart disease mortality among blacks may indeed not be declining, as it is for white populations. Major contributors to these findings in blacks are an incroased prevalence and severity of hypertension, a possibly increased susceptibility to end-organ damage, socioeconomic factors and beliefs that affect hypertension control, and very possibly some obsolete treatments that focus on blood pressure numbers and do not emphasize the black person and the associated risk factors. Diuretic therapy has long been the mainstay treatment for black hypertensives, but the effects of diuretics on lipid levels and left ventricular hypertrophy, among other factors, should be carefully assessed. A recont study of β-blockers in blacks showed that metoprolol was effective and well tolerated. Consideration of epidemiologic, pathophysiologic, and pharmacotherapeutic features of hypertension in blacks may require traditional views of this disease and its treatment in this special population to be reevaluated.
Perifusion model system to culture bovine hypothalamic slices in series with dispersed anterior pituitary cells.

Dispersed bovine anterior pituitary cells were incubated either in static or perifusion cultures to assess basal growth hormone release as well as stimulatory and inhibitory effects of growth hormone-releasing hormone and somatostatin, respectively, on growth hormone release. Total concentrations of growth hormones over a 12-hour incubation period were fivefold greater in perifused than in static cultures (2034 ± 160 vs. 387 ± 33 ng/12 h). A dose-dependent increase in growth hormone secretion in response to challenge with growth hormone-releasing hormone (10−12 to 10−8M) for 1 h was observed in both static and perifusion cultures; however, perifused cells were more responsive to the same concentration of neuropeptide than those in static culture. Concentrations of somatostatin (10−12 to 10−8M) for 1 h did not inhibit basal growth hormone secretion in either static or perifusion cultures. To establish model, slices of the hypothalamus, immediately adjacent to the sagittal midline, were perifused in series with anterior pituitary cells, and media effluent was assayed for growth hormone concentrations. Release of growth hormone was pulsatile and seemed to mimic the episodic pattern of bovine secretion. Hypothalamic slices were placed in one chamber of the perifusion system, and basal secretion of growth hormone-releasing hormone and somatostatin was pulsatile in media effluent. Tissue viability of hypothalamic slices and anterior pituitary cells was evaluated by KCl depolarization. Tissues were viable for at least 120 h. Thus, this hypothalamo-pituitary dual chamber perifusion system is a valid in vitro model to study regulation of growth hormone secretion.
Single Parenthood, Achievement, and Problem Behavior in White, Black, and Hispanic Children.

The author investigated whether adverse effects of single parenthood not observed in 6-7-year-old NLSY (National Longitudinal Study of Youth) children might emerge when they reached 12-13 years of age. Outcomes included mathematics, reading, vocabulary scores, and behavior problem ratings. Little or no evidence of systematic negative effects emerged at the later age except for some isolated findings in the Black sample that suggested that vocabulary scores were somewhat negatively influenced by years of single parent experience and positively affected by extended 2-parent experience. The general absence of adverse effects, as well as the minimally significant relationships found in the Black sample, may be explained in terms of the role played by maternal education and ability. The findings suggest that the presence of positive maternal attitudes and parenting resources may significantly mitigate the likelihood of adverse child outcomes of single parenthood.
Effect of Various Dietary Supplements on Growth and Lactation in the Albino Mouse.

SummaryOn the basal diets studied, ascorbic acid has been shown to have no influence on the growth rate of mice. Purified diets containing 8% yeast are not adequate for lactation in mice. Both dehydrated grass and wheat bran effectively increase lactation, but these two substances when added to a basal purified diet alone or combined do not provide for as good lactation as does a stock commercial diet. It has been concluded that the lactation-promoting effect of the dehydrated grass and wheat bran is not due to an increase of thiamin, riboflavin, pantothenic acid, factor W, or inositol in the diet.
Comment on ''friction between incommensurate crystals''

We present results from an independent analysis of friction that more generally addresses all crystalline materials by an extension of coincident site lattice theory and dislocation drag. Calculations for graphitic friction are carried out and agree in magnitude with experimental friction forces. More interestingly, static, dynamic and anisotropic friction forces, incommensurability effects and superlubricity are explained by a more rigorous analysis of the dislocation structure at a sliding interface.
A New ‘Idea of Nature’ for Chemical Education

“The idea of nature” (general model of how things work) that is accepted in a society strongly influences that group’s social and technological progress. Currently, science education concentrates on analysis of stable pre-existing items to minimum constituents. This emphasis is consistent with an outlook that has been widely accepted since the late Renaissance—that characteristics of individuals depend exclusively on the properties of their microscopic components. Much of 19th and 20th century science seems compatible with that now-traditional outlook. But major parts of contemporary science (and fundamental technological problems) deal with open-system dynamic coherences that display novel and important characteristics. These important entities are not adequately treated by the presently-dominant idea of nature. In contrast, the notion of how the world works that contemporary science and current technological practice generate emphasizes synthesis and self-organization of far-from-equilibrium “dissipative structures.” Arguably, eventual success in meeting the severe technological and social challenges occasioned by increasing world population will require general diffusion and appreciation of that newer overall outlook. Chemistry educators have been important in developing and disseminating the earlier worldview—they can and should provide leadership for widespread adoption of the alternative idea of nature.
Identification and primary structural analysis of peptide II, an end-product of precursor processing in cells R3-R14 of Aplysia

Peptide II, which is encoded on a gene for a precursor protein in abdominal ganglion neurons R3-R14, was purified from extracts of abdominal ganglia of Aplysia californica. Native peptide II comigrates with synthetic standards on HPLC under isocratic conditions. Amino acid sequence and composition analyses indicate that the sequence of peptide II is Glu-Ala-Glu-Glu-Pro-Ser-Phe-Met-Thr-Arg-Leu, as predicted from the precursor. The molluscan cardioexcitatory peptide Phe-Met-Arg-Phe-amide was also identified in abdominal ganglion extracts by similar means. The large amount of peptide II recovered (100 ng/ganglion), and its location on the precursor between two pairs of basic residues, strongly suggest that the precursor is processed into peptide II and at least two other peptides. Although cells R3-R11 have been postulated to play a role in cardiovascular control, peptide II was without effect at less than or equal to 10(-4) M concentrations on identified abdominal ganglion neurons, the gastroesophageal artery or the heart. The physiological role of peptide II therefore remains to be elucidated.
The Effects of Implicit Theories on Exercise Motivation

Abstract This study investigated whether type of implicit theory about athletic coordination would influence motivation to persist at a novel exercise task in the face of difficulty. Fifty college students were told that we were testing a new type of exercise and were given one of two theories about the nature of athletic coordination. Some participants were told that athletic coordination was mostly learned (incremental condition), while others were told that athletic coordination was genetically determined (entity condition). Participants initially experienced success and then difficulty while following videos containing the new exercise. Consistent with predictions, results showed that participants given an incremental theory of athletic coordination reported greater motivation and self-efficacy and less negative affect in the face of difficulty than those given an entity theory. Implications of these findings are discussed.
Acidic deposition impacts mediated by sulfur cycling in a coastal plain forest ecosystem

Deposition in the New Jersey Pinelands was very acidic (pH=4.17) and contained high levels of SO2−2 based on bulk deposition measurementsfrom July 1984–July 1986. Streamwater over the same interval in undisturbed watersheds was less acidic (pH =4.52) and had proportionately less SO4−2. A preliminary alkalinity budget for undisturbed watersheds suggested that SO4−2 retention within Pinelands watersheds accounted for a large portion of the total alkalinity generated and thereby lessened the impact of acidic deposition on surface waters. The only process capable of explaining the retention of SO4−2 was microbial sulfate reduction in the extensive wetlands surrounding Pinelands streams which occurred at high rates.
Visuoperceptual and visuomotor abilities and locus of lesion

Abstract Possible differential effects of laterality and caudality of cerebral lesions on simple visuoperceptual and visuomotor skills were examined. As expected, the right hemisphere lesion group was significantly more impaired than the left hemisphere lesion group. The effects of the caudality of lesion, however, yielded interesting results. While the right posterior lesion group was worse than the right anterior lesion group, as expected, the left posterior lesion group was better than the left anterior lesion group. Our finding points to a possibility that the left hemisphere, especially the anterior region, might not be as silent in processing simple visual stimuli as has been accepted.
Artfulness in Young Children's Spoken Narratives.

Research Findings: Artfulness is rarely considered as an indicator of quality in young children's spoken narratives. Although some studies have examined artfulness in the narratives of children 5 and older, no studies to date have focused on the artfulness of preschoolers' oral narratives. This study examined the artfulness of fictional spoken narratives produced by 43 children aged 3 and 4. Each preschooler's narrative was coded using a 15-code system adapted from previous studies of artfulness in school-age children's narratives. These elements of children's narratives were compared to 3 traditional measures of narrative quality: complexity (mean length of T-units), productivity (total number of T-units), and lexical diversity (number of different words). In addition, the relations between children's narrative artfulness and their performance on a standardized measure of general language ability were examined. Results showed a wide range of code use across the sample. Narrative artfulness positively cor...
Radiative flux and flux divergence of a Lorentz line

Abstract Exact and approximate results are obtained for the radiative flux and the radiative flux divergence in a plane-parallel layer of a gas of uniform properties due to a Lorentz broadened line.
Fine structure of the rectal pads in the desert locust Schistocerca gregaria with reference to the mechanism of water uptake.

Abstract The rectal pads of Schistocerca gregaria are composed of three different cell types: epithelial, secondary and junctional cells. The rectal pads are interconnected by simple rectal cells and both are lined internally by a articular intima. The epithelial cells exhibit extensive infoldings of the apical plasma membranes that are closely associated with mitochondria. Their lateral plasma membranes are highly folded around large mitochondria and enclose intercellular channels and spaces. They are united by belt and spot desmosomes, septate junctions, gap junctions and scalariform junctions, but terminate in a basal syncytium without contacting the basal plasma membranes. The apical and basal cytoplasm contain coated vesicles, dense tubular elements, multivesicular bodies and lysosomes, suggesting receptor-mediated endocytosis of small peptide molecules into the epithelial cells. The apical membrane infoldings of the secondary cells are also associated with large mitochondria. Their basal plasma membranes are covered by connective cell processes and connected with them by spot desmosomes which may be involved in solute recycling. The presence of neurosecretory-like axons near the secondary cells suggests that they exert local control on the function of these cells. The ultrastructural details are examined in relation to their role in solute and water transport.
Aerosol size distributions and aerosol volume formation for a coal-fired power plant plume

Abstract During the summer of 1976, the plume from the Labadie power plant near St. Louis, Missouri was mapped on two days using an instrumented aircraft. The mapping consisted of measuring horizontal and vertical concentration profiles of both aerosol and gas contaminates for cross-sections of the plume. Measurements were made for plume travel times of up to 2 h and distances downwind of up to 50 km. Aerosol size distribution determinations were made in both the plume and surrounding background air mass. Characterization of these distributions was done in terms of two additive log-normal functions: one describing nuclei less than 0.03 μm in size and the second describing accumulation mode aerosol between 0.03 and 1.0 μm. On the average, results show that distribution of the nuclei volume for aerosol size less than 0.03 μm in both plume and background can be parameterized with a geometric mean size of 0.021 ± 0.005 μm and a geometric standard deviation of 1.5 ± 0.1. Total nuclei volume is found to be about 1% of total submicron aerosol volume. For aerosol larger than 0.03 μm, the geometric mean size of aerosol volume distributions in a daytime plume under uniform meteorological conditions was found to be 0.18 ± 0.02 μm . This is significantly different from the 0.23 ± 0.01 μm measured for background air. The dispersion of the distribution in this size range, measured by a geometric standard deviation of 1.92 ± 0.04, does not change significantly from in-plume to background. For a plume, measured in a morning transition period where average aerosol volume concentrations reached 87 μm 3 cm −3 , average volume mean geometric size for in-plume aerosol was 0.15 ± 0.01 μm vs 0.18 ± 0.01 μm in the background. Here, dispersion of the size distribution was narrower in the plume, with σ g = 1.63 ± 0.04 vs 1.86 ± 0.03 for background aerosol. Together with the integral Aitken nuclei concentration and b scat values, the aerosol size distribution measurements have been used to reconstruct the aerosol time history, up to two hours, for the various plumes investigated. Total aerosol volume flow through each cross-section of the plume has been calculated. When corrected for background levels, this flow is generally found to increase with time from levels as low as 60 cm 3 s −1 to about 400 cm 3 s −1 . Assuming the excess volume formed is sulfuric acid in equilibrium with water vapor at the ambient r.h., we obtain an average SO 2 conversion rate of 0.7 ± 0.4% h −1 for the first 2 h of plume development.
A New Mixture Model for Misclassification With Applications for Survey Data

Social scientists often rely on survey data to examine group differences. A problem with survey data is the potential misclassification of group membership due to poorly trained interviewers, inconsistent responses, or errors in marking questions. In data containing unequal subsample sizes, the consequences of misclassification can be considerable, especially for groups with small sample sizes. In this study, the authors develop a new mixture model that allows researchers to address the problem using the data they have. By supplying additional information from the data, this two-stage model is estimated using a Bayesian method. The method is illustrated with the Early Childhood Longitudinal Study data. As anticipated, the more information supplied to adjust for group membership, the better the model performs. Even when small amounts of information are supplied, the model produces reasonably robust estimates and improves the fit compared to the no-adjustment model. Sensitivity analyses are conducted on cho...
The comparative developmental neurotoxicity of lead in humans and animals

Abstract The effects of lead on neurobehavioral development have been extensively investigated in humans as well as animals. This valuable lode of research findings offers a basis for comparing the developmental neurobehavioral toxicity of lead across species and for assessing the validity of animal models of developmental neurotoxicity. Comparisons of human and animal findings suggest that the greatest qualitative similarities involve relatively complex behavioral processes such as cognition and learning. Quantitative comparisons based on dose-response relationships for these endpoints are difficult to make because the relationships are sometimes nonmonotonic (U-shaped) and because blood lead levels may not be directly comparable between species. However, the lowest levels of exposure at which developmental neurobehavioral effects have been observed are similar: 10–15 μg/dl in children,
Estimating interfacial areas for multi-fluid soil systems

Abstract Knowledge of the fluid-fluid and fluid-solid interfacial areas is important to better understand and quantify many flow and transport processes in porous media. This paper presents estimates for interfacial areas of porous media containing two or three fluids from measured capillary pressure (Pc)-saturation (S) relations. The thermodynamic treatment of two-fluid Pc−S relations presented by Morrow (1970) served as the basis for the predictions. In media containing two fluids (air-oil, air-water, oil-water), the solid-nonwetting interfacial area ( A sN ∗ ) equaled zero when the solid was completely wetted by the wetting fluid. The area under the Pc−S curve was directly proportional to the nonwetting-wetting interfacial area ( A NW ∗ ). If the solid surface was not completely wetted by one fluid, A NW ∗ and A sN ∗ were estimated by weighed partitioning of the area under the Pc−S curve. For porous media with fractional wettability, the procedure was applied separately to water- and oil-wet regions. The values of A NW ∗ and A sN ∗ were highest and lowest, respectively, in systems that were strongly wetted. In three-fluid media the wetting and spreading behavior of the liquids greatly affected the estimated interfacial areas. For a water-wet medium with a continuous intermediate oil phase, the interfacial areas were predicted from Pc−S data in a similar manner as for two-fluid media. The oil-water and oil-solid interfacial areas were estimated from the oil-water Pc−S curve, while the air-oil interfacial area was obtained from the air-oil Pc−S curve. For a fractional wettability or oil-wet medium there may be as many as six interfaces. These interfacial areas were estimated from three-fluid Pc−S relations based on previously developed methods for predicting three-fluid Pc−S relations from two-fluid data.
The Life-Spans of Empires

Abstract The collapse of empires is exceedingly difficult to understand. The author examined the distribution of imperial lifetimes using a data set that spans more than three millennia and found that it conforms to a memoryless exponential distribution in which the rate of collapse of an empire is independent of its age. Comparing this distribution to similar lifetime distributions of other complex systems—specifically, biological species and corporate firms—the author explores the reasons behind their lifetime distributions and how this approach can yield insights into empires.
Changes in Stroke Epidemiology, Prevention, and Treatment

Stroke is arguably the most feared cardiovascular event among healthy subjects and those with cardiovascular disease. Recent studies document changes in the epidemiology of stroke, both within and beyond the United States, which will impact medical service needs. Advances in our treatments for primary and secondary prevention herald an exciting period of change, which promises to lower stroke rates. In the United States, as with other industrialized countries, stroke rates, adjusted for age, declined over the last 30 years.1–3 However, the aging population implies that absolute numbers of stroke may stabilize or increase over the next 2 decades.4 These changes in population demographics and overall risk of disease will place demands on health services for both acute stroke care and long-term care associated with more severe loss of function. New risk scores can risk-stratify patients presenting with stroke and provide insights into the likelihood of long-term disability.5 The temporal changes will also impact future trials of stroke prevention, because lower rates of stroke in usual care groups will drive larger sample sizes for trials evaluating new therapies.6 The global perspective is quite different. Continuing industrialization of Asia and Africa is increasing unhealthy lifestyles, which promote stroke and other cardiovascular disease. As a result, the highest rates of stroke mortality and disability-adjusted life years lost occur in Asia, Russia, and Eastern Europe.7 Stroke is increasing rapidly in Eastern Europe and Central Asia compared with Western Europe3 and the United States.1,2 In China, rates of stroke and other cardiovascular disease are projected to increase dramatically due to combination of an aging population and the high prevalence of smoking and hypertension.8 The types of stroke are also changing in rapidly developing Asian countries such as China, with an increase in ischemic …
Black and White and the Inverted Spectrum

To the familiar idea of an undetectable spectrum inversion some have added the idea of inverted earth. This new combination of ideas is even harder to make coherent, particularly as it applies to a supposed inversion of black and white counteracted by an environmental switch of these. Black and white exhibit asymmetries in their connections with illumination, shadow and visibility, which rule out their being reversed. And since the most saturated yellow is light and the most saturated blue dark, yellow and blue could not be reversed unless light and dark could be. The difficulties suggest some more general morals for how to think of the role of “qualia” in colour perception.
Combining creel intercept and mail survey methods to understand the human dimensions of local freshwater fisheries

Creel surveys were conducted by Texas Parks and Wildlife Department at two lakes were used as a means of sampling anglers for follow-up mail surveys. After the collection of fisheries dependent data from fishing parties on randomly selected days, anglers were randomly selected and told of an forthcoming mail survey they would receive within 90 days. They were asked to provide their names and addresses on a confidential basis. The mail survey provided detailed coverage of the anglers intercepted (e.g. their social and demographic characteristics, level of fishing experience and involvement, experience preferences, consumptive orientation, management preferences, attitudes and satisfaction levels), characteristics of the trip when they were intercepted (i.e. trip length, party size and expenditures by location), and lake-specific issues of concern to management. This add-on methodology is described with particular attention to sample size considerations, creel intercept and mail survey procedures, recall bias, response rates and administrative concerns.
Humoral hypercalcemia due to an occult renal adenoma

Humoral hypercalcemia refers to the elevated blood calcium levels caused by neoplasms which release a bone resorptive substance into the circulation. Previously reported infants with malignant and benign solid tumors causing humoral hypercalcemia have presented with large abdominal masses. The case we describe, a hypercalcemic infant due to an occult parathyroid hormone-related protein-containing metanephric adenoma of the kidney, shows that radionuclide bone scanning can be a useful test to identify humoral hypercalcemia. Humoral hypercalcemia stemming from a soft tissue neoplasm should be ruled out, even in the absence of clinical signs of a tumor, if bone scans show generalized uptake in the absence of hypervitaminosis D or radiological signs of bone lesions, and serum parathyroid hormone is low.
A Novel Analog Decision-Feedback Equalizer for 10-Gb/sec Multi-Mode Fiber Dispersion Compensation

A novel analog decision-feedback equalizer (ADFE) is presented to compensate for modal dispersion in multi-mode fibers. The unclocked continuous-time technique and circuit architecture aims to overcome the first feedback-loop latency challenge in conventional digital or mixed-signal DFEs. An ADFE employing a 4-tap forward filter and a 1-tap feedback filter is fabricated in a 0.18-mum CMOS process. The chip with pads occupies 1.04 mm2 and draws 240 mA DC current from a 1.8 V supply at a typical process corner. The circuit consumes significantly less area and power than a digital or mixed-signal approach and is used to equalize 300 meters of MMF at 10-Gb/sec.
Nuclear Export Pathways of tRNA and 40 S Ribosomes Include both Common and Specific Intermediates

Different classes of RNAs are exported from Xenopus laevis oocyte nuclei by facilitated pathways. We have performed kinetic competition analyses to investigate the relationship between the export pathways of microinjected tRNA and ribosomal subunits. Saturating concentrations of ribosomal subunits do not compete tRNA export. Thus, the saturable factor in the ribosomal subunit export pathway is not limiting for tRNA export. The co-microinjection of ribosomal subunits did, however, stimulate the rate of tRNA export. Co-injected mRNA also stimulated tRNA export. tRNA export itself displays positive cooperative export kinetics that are abrogated by saturating concentrations of rRNA. These results are consistent with the existence of common high affinity RNA-binding sites that can be titrated with tRNA, rRNA or ribosomal subunits, and mRNA. Furthermore, high concentrations of tRNA are also shown to have moderate inhibitory effects on 40 S subunit export, indicating a lower affinity common intermediate also shared by mRNA.
Relationship of Cell Sap pH to Organic Acid Change During Ion Uptake

Excised roots of barley (Hordeum vulgare, var. Campana) were incubated in KCl, K(2)SO(4), CaCl(2), and NaCl solutions at concentrations of 10(-5) to 10(-2)n. Changes in substrate solution pH, cell sap pH, and organic acid content of the roots were related to differences in cation and anion absorption. The pH of expressed sap of roots increased when cations were absorbed in excess of anions and decreased when anions were absorbed in excess of cations. The pH of the cell sap shifted in response to imbalances in cation and anion uptake in salt solutions as dilute as 10(-5)n. Changes in cell sap pH were detectable within 15 minutes after the roots were placed in 10(-3)n K(2)SO(4). Organic acid changes in the roots were proportional to expressed sap pH changes induced by unbalanced ion uptake. Changes in organic acid content in response to differential cation and anion uptake appear to be associated with the low-salt component of ion uptake.
CamkII Phosphorylation of RyRs: a Mechanistic Mathematical Model

During heart failure (HF), the ability of the sarcoplasmic reticulum (SR) to store Ca2+ is severely impaired resulting in abnormal Ca2+ cycling and excitation-contraction (EC) coupling. While it has been demonstrated that SR Ca2+ ATPase function is reduced and Na+/Ca2+ exchanger function is up-regulated in HF, recently it has been proposed that “leaky” ryanodine receptors (RyRs) also contribute to diminished Ca2+ levels in the SR. Various groups have experimentally investigated the effects of RyR phosphorylation mediated by Ca2+/calmodulin dependent kinase II (CaMKII) and other kinases on RyR behavior. Some of these results are inconsistent, and are difficult to interpret since RyR gating is modulated by many external proteins and ions, including Ca2+. Here, we present a mathematical model representing CaMKII-RyR interaction in the canine ventricular myocyte. This is an extension of our previous model which characterized CaMKII phosphorylation of L-type Ca2+ channels (LCCs) in the cardiac dyad. In this model, it is assumed that upon phosphorylation, RyR Ca2+-sensitivity is increased. Individual RyR phosphorylation is modeled as a function of dyadic CaMKII activity, which is modulated by local Ca2+ levels. The model is constrained by experimental measurements of Ca2+ spark frequency and steady state RyR phosphorylation. It replicates steady state RyR (leak) fluxes in the range measured in experiments without the addition of a separate leak flux pathway. Interestingly, simulation results suggest that CaMKII phosphorylation of LCCs, but not RyRs, significantly increases RyR flux; i.e., increasing trigger Ca2+ has a stronger impact on RyR flux than phosphorylation-induced increases in RyR open probability under physiological conditions. We also show that phosphorylation of LCCs decreases EC coupling gain significantly. These results suggest that LCC phosphorylation sites may be a more effective target than RyR sites in modulating RyR flux and regulating abnormal Ca2+ cycling.
Whither Brain Death

The publicity surrounding the recent McMath and Munoz cases has rekindled public interest in brain death: the familiar term for human death determination by showing the irreversible cessation of clinical brain functions. The concept of brain death was developed decades ago to permit withdrawal of therapy in hopeless cases and to permit organ donation. It has become widely established medical practice, and laws permit it in all U.S. jurisdictions. Brain death has a biophilosophical justification as a standard for determining human death but remains poorly understood by the public and by health professionals. The current controversies over brain death are largely restricted to the academy, but some practitioners express ambivalence over whether brain death is equivalent to human death. Brain death remains an accepted and sound concept, but more work is necessary to establish its biophilosophical justification and to educate health professionals and the public.
Joint Optimization of Transportation and Spare Parts Inventory Policies in a Reverse Logistics Network Using OptQuest

The aim of this study is the joint optimization of the transportation and spare parts inventory policies in a reverse logistics (RL) network designed for End of Life (EOL) television (TV) recyling. Besides recycling, Printed Circuit Boards (PCBs) recovered from EOL TVs are used to meet the spare PCB demand. In order to model this RL network with its disassembly, transportation and spare parts inventory related aspects, a discrete event simulation (DES) model has been developed in detail using Arena simulation software. Next, Arena OptQuest has been used to propose optimum number and size of trucks together with the optimum reorder (s) and order quantity (Q) levels for the spare PCBs based on the minimization of total cost which includes inventory holding, PCB recovery, new PCB acquisition, truck amortization and operating costs.© 2008 ASME
The additive impact of anxiety and a placebo on pain.

Objective. We investigated the effects of pain anxiety and a placebo/nocebo/neutral intervention on ice water-induced pain. Design. We divided 72 volunteers into high- and low-anxiety groups before randomly assigning them to experimental and control subgroups. Method. Participants completed preimmersion tests of pain anxiety, pain worry, and mood. We scored first immersion pain behavior, experience, and intensity. Each subgroup then received an instruction designed to elicit a positive (placebo), negative (nocebo), or neutral response. After repeating the pain worry test, we gathered second immersion pain scores, and participants repeated the mood test, completed the treatment credibility measure, and were debriefed. Outcome Measures. We used the Pain Anxiety Symptom Scale; self-rating Likert-type scales for pain worry, pain intensity, and pain-coping; the Multiple Affect Adjective Checklist (mood); timed measurements for pain threshold and pain tolerance; and a treatment credibility scale. Results. Pain anxiety and the placebo interventions significantly altered participants' pain scores, with best-to-worse scores reported by the low pain-anxiety/placebo, high anxiety/placebo, low anxiety/neutral, low anxiety/nocebo, high anxiety neutral, and high anxiety/nocebo groups. The high pain-anxiety group demonstrated the greatest response to the placebo/nocebo intervention in the expected directions in pain, worry, and anxious mood scores and in decreased self-confidence in managing pain (this was also negatively affected by the nocebo in each pain-anxiety group). Conclusion. This study demonstrates that the interaction of the personality variable of pain anxiety with the placebo/nocebo response has an impact on pain, worry, and mood.
Nerve growth factor: Basic findings and clinical trials

The nerve growth factor is the first-discovered and best-characterized member of the family of neurotrophins. In the introduction of this article we present a brief biographic view of past and present studies of Rita Levi-Montalcini on nerve growth factor: Further, the article focuses on pleiotropic activities of nerve growth factor, exerting on various cell types, including cells of nervous, immune and endocrine system. Implications of these actions of nerve growth factor in the pathogenesis of neurological diseases, autoimmune-inflammatory diseases, allergic diseases, lymphoproliferative diseases, atherosclerotic cardiovascular disease, and neurotrophic corneal ulcers are outlined. Biomedical Reviews 1999; 10: 3-14.