cssi/SciSciGPT-SciSciNet huggingface dataset:
Using Biochemical and Structural Approaches to Study ErbB2-Containing Heterodimers

Dimerization of epidermal growth factor receptor (EGFR/ErbB) homologs is necessary for their activation. Dysregulation of each of these receptors is linked to a variety of cancers. Most members of this protein family adopt a tethered conformation in the absence of ligand that prevents the formation of active dimers, while ErbB2 adopts a constitutively extended conformation mimicking the ligand-bound conformation. Surprisingly, ErbB2 does not homodimerize yet is the preferred dimerization partner of the other EGFR homologs. The reasons for this are unclear, and previous attempts to address these questions using structural techniques were unsuccessful. Here we drove dimerization of the extracellular domains of EGFR family members with ErbB2 by fusion of one extracellular domain to the light and the other to the heavy chain of an antibody. We pursued crystallization of these heterodimers, and currently use small angle x-ray scattering and electron microscopy to determine the structure of these heterodimers in the presence and absence of ligand to reveal what structural facets underlie their activation.
Effect of succinylation of cottonseed flour during protein extraction on the yield and some of the properties of protein isolates

A new method has been developed to improve extraction and recovery of protein isolates, which are highly water-soluble, low in sensitivity to calcium precipitation and light-colored, from defatted cottonseed flour. Optimal conditions include extraction of flour with acidified n-butanol (pH 4.5) to remove chromophores, succinylation of proteins at pH 8.5 using succinic anhydride at a concentration of 30% on protein basis, and precipitation of protein at pH 4.5. The resulting succinylated isolates contain more hydrophobic and neutral amino acids than untreated isolates. Gel filtration chromatography and polyacrylamide gel electrophoresis of protein isolates (water-, salt [4% NaCl]- and alkali [0.2% NaOH]-soluble), sequentially fractionated from succinylated and untreated flours, suggest that succinylation converts much of the salt- and alkali-soluble proteins to water-soluble forms. Succinylation increases emulsion stability of isolates. The 3 succinylated isolates showed similar Chromatographie patterns on Sephadex G-100 columns and clectrophoretic mobilities in polyacrylamide gels, whereas the corresponding 3 isolates from untreated flour had different gel patterns and mobilities. Mobilities of major protein components of the 3 isolates were increased by succinylation.
Inhibition of animal tissue ATPase activities by chlorinated hydrocarbon pesticides.

Abstract 4 chlorinated hydrocarbon pesticides—chlordane, lindane, DDT and dicofol (Kelthane)—tested on tissue homogenates inhibited both the Na+-K+ ATPase and Mg2+ ATPase enzyme systems. Discrete fractions were obtained by differential and density-gradient centrifugation of tissue homogenates from rabbits, chickens, lake trout, and cockroaches; they included red blood cells, brain, olfactory, kidney, heart, liver and muscle. At low concentrations DDT was the most effective inhibitor of the Mg2+ ATPase. At higher concentrations, Kelthane produced the greatest inhibition of both ATPase activities. Chlordane and lindane also inhibited both ATPases with the former being the more effective. Red blood cell “ghosts” (plasma membranes) differed from other tissues in that its Na+-K+ ATPase activity was insensitive to the insecticides, except for a slight effect from Kelthane. The Mg2+ ATPase activity of a muscle fraction B from different sources was significantly more affected by the pesticides than that of a liver fraction B.
Health effects of exposure to low doses of nerve agent--a review of present knowledge.

Extensive data are available on nerve agents as they relate to low dose toxicity. Highly sensitive in vitro and in vivo mutagenicity and clastogenicity screens as well as subchronic toxicity studies in various animal models have been carried out. the majority of such closely controlled toxicological studies in the United States have been conducted at the National Center for Toxicological Research or at the University of California. Data available on humans exposed to nerve agents are obtained primarily from human volunteer studies and accidental exposures. the former consists of experiments conducted by the U.S. Army between 1958 and 1975. Cases of accidental exposures were occupational hazards of chemical munition production workers. Controlled studies of human exposures, reports of accidental exposures, and animal studies collectively indicate that exposures to OP nerve agents at levels causing no acute signs or symptoms do not produce chronic illness
Extreme value statistics related to performance of a standard air quality simulation model using data at seven power plant sites

Abstract Concentrations of sulfur dioxide from model estimates and monitoring stations are available from previously conducted point source studies at seven power plant monitoring networks. Data for two to seven monitoring stations for either one or two years are available for examination of extreme values (specifically second highest, once-a-year) for 3 and 24 h averaging times. These data total 43 monitoring station-years. Stations whose elevations relative to the plant stack height result in the CRSTER model's marginal applicability, show overestimated concentrations by the same model. After removing those data which exceed a specific elevation criteria (6 of the 43 data sets), the comparison of second highest 3 and 24 h model estimates with measurements, although containing considerable scatter, reveals no significant bias toward over or undercalculation. For 24 h periods 68 % are within a factor of two; for 3 h periods 84 % are within a factor of two. Since this analysis is based upon a small number of monitoring stations per plant site (no more than 7), the transferability of these results to the interpretation of model estimates used to satisfy regulatory requirements, where the largest concentrations of many receptor points is used, is unknown.
Complex formation in sonicated mixtures of β-lactoglobulin and phosphatidylcholine

β-Lactoglobulin, the major whey protein of bovine milk, is secreted via the endomembrane system of the mammary gland. The primary structure of β-lactoglobulin shares certain characteristics with membrane proteins, although the soluble protein assumes a globular conformation. We have prepared complexes of β-lactoglobulin and phosphatidylcholines by dissolving both in a helix-forming solvent (chloroform methanol). The complex is stable when transferred to aqueous solutions and sonicated to form vesicles. Both ionic and hydrophobic interactions appear to be involved in complex formation. We have used spectroscopy (circular dichroism, fluorescence, and nuclear magnetic resonance) and electron microscopy to study these complexes. At pH 3.7, the small, single bilayer vesicles produced by sonication are protected against aggregation by the presence of the protein. As determined by circular dichroism, the proportion of α-helix in β-lactoglobulin is increased by complexation with phosphatidylcholine. Circular dichroism and fluorescence spectra show the involvement of at least 1 tryptophan residue in the conformational change. At pH 7.2, β-lactoglobulin-phosphatidylcholine vesicles form aggregates as observed by electron microscopy and31P nuclear magnetic resonance spectroscopy. These aggregated vesicles could be resuspended by raising the pH. The ability of the partially unfolded β-lactoglobulin to interact with lipids is believed to be important to its transport through the endomembrane system.
Defining difference, forging unity: The co‐construction of race, ethnicity and nation in Belize

Abstract This article examines competing nationalist projects which compete to constitute a Belizean nation: pluralist nationalism constructs the nation as ethnically diverse; synthetic nationalism attempts to submerge ethnic or racial difference into a shared national identity; hegemonic nationalism works to attach preferentially a single racial identity to the nation and exclude other identities. Within these projects, the homogenizing processes which construct national sameness are integrally related to the individualizing processes which constitute subnational difference: both national sameness and subnational differences are constituted in terms of race, ethnicity, or a conflation of the two. The article explores how the essentialization of racial, ethnic and national identities facilitates their assimilation of one another.
Estimating vaccine efficacy from outbreak size household data in the presence of heterogeneous transmission probabilities.

We develop a Bayesian approach for estimating vaccine efficacy for susceptibility ( VE S ) and infectiousness ( VE I ) using outbreak size household data. Our method allows for heterogeneity in transmission probabilities due to factors that are related to individual' characteristics, such as age, in addition to vaccination status. It also allows for between-household heterogeneity in transmission probabilities due to random effects associated with households, such as genetic or environmental effects. Using age as a potential covariate causing heterogeneity in individual' transmission probabilities in households consisting of adults and children, we present the results of a simulation study designed to evaluate the performance of the proposed estimators of VE S and VE I . We found that estimates of VE I have larger bias and variance compared to those of VE S . We also use the approach to compare two vaccination designs: one vaccinating both adults and children, the other only children. Simulations reveal t...
Gender and Participation in High School and College Instrumental Jazz Ensembles.

This study is an examination of the relationship between gender and participation in high school and college instrumental jazz ensembles. Student demographic and attitudinal information was collected using the researcher-designed Instrumental Jazz Participation Survey (IJPS). Undergraduate college band students (N=628) representing 15 programs offering degrees in music education were surveyed. Gender and jazz ensemble participation were found to be related at both levels; 52% of women and 80% of men surveyed reported playing jazz in high school, and 14% of women and 50% of men played in college. The results indicated that attitudes toward participation are influenced by both gender and jazz experience. Women and men were found to differ in their stated reasons for quitting jazz. Women's decisions to discontinue were affected by primary instrument selection, institutional obstacles that narrow participation options, feeling more comfortable in traditional ensembles, and an inability to connect jazz partici...
ASME 1995 Nadai Lecture—Plasticity of Porous and Particulate Materials

The paper discusses the formulation of constitutive equation for those materials for which the irreversible changes of the volume is also to be taken into account. These are mainly geomaterials, cement, powders of various kinds, ceramics, etc. Experimental evidence is first presented showing that the time effects on irreversible volumetric changes and failure are very important. The concept of compressibility/dilatancy boundary is further introduced. The general constitutive equation able to describe instantaneous response, transient and stationary creep, dilatancy and/or compressibility during creep, failure, creep damage and creep failure, is presented. Examples formulated for various materials are given. Comparison between model prediction and experimental data shows a very good agreement. A few examples of applications of the model to mining engineering problems are mentioned.
Mapping stem cell activities in the feather follicle

It is important to know how different organs 'manage' their stem cells. Both hair and feather follicles show robust regenerative powers that episodically renew the epithelial organ. However, the evolution of feathers (from reptiles to birds) and hairs (from reptiles to mammals) are independent events and their follicular structures result from convergent evolution. Because feathers do not have the anatomical equivalent of a hair follicle bulge, we are interested in determining where their stem cells are localized. By applying long-term label retention, transplantation and DiI tracing to map stem cell activities, here we show that feather follicles contain slow-cycling long-term label-retaining cells (LRCs), transient amplifying cells and differentiating keratinocytes. Each population, located in anatomically distinct regions, undergoes dynamic homeostasis during the feather cycle. In the growing follicle, LRCs are enriched in a 'collar bulge' niche. In the moulting follicle, LRCs shift to populate a papillar ectoderm niche near the dermal papilla. On transplantation, LRCs show multipotentiality. In a three-dimensional view, LRCs are configured as a ring that is horizontally placed in radially symmetric feathers but tilted in bilaterally symmetric feathers. The changing topology of stem cell activities may contribute to the construction of complex feather forms.
Temporal Changes of the Primary Circulation in Tropical Cyclones.

Abstract More than 900 radial profiles of in situ aircraft observations collected in 19 Atlantic hurricanes and tropical storms over 13 years confirm that the usual mechanism of tropical cyclone intensification involves contracting maxima of the axisymmetric swirling wind. Radar shows that annuli of convective echoes accompany the wind maxima. These features, called convective rings exist and move inward because latent heat released in the rings leads to descent, adiabatic warming, and rapid isobaric height falls in the area they enclose. The radial change in rate of isobaric height fall is concentrated at the inner edge of the wind maximum, causing the gradient wind to increase there and the maximum to contract. Vigorous convection organized in rings invariably causes well defined, inward moving wind maxima, but when convection is weak, the rings are also weak or even absent. In this case, the swirling wind may be nearly constant with radius and change slowly in time. Hurricanes that have a single, vigor...
Effect of 2,2-bis(2-chlorophenyl-4-chlorophenyl)-1,1-dichloroethane (o,p′-DDD) on cellular respiration in adrenal carcinoma☆

Abstract The effect of o,p′ -DDD on cellular respiration in human adrenal tissue and animal liver, kidney, and adrenal tissue was examined. In these tissues, cellular respiration is completely inhibited at a drug concentration of 0.625 m m and approaches control respiratory rates at a concentration of 0.039 m m . Oxidative phosphorylation does not appear to be uncoupled in the presence of the drug. This study suggests that o,p′-DDD affects cellular respiration of mitochondria in general. It is speculated that adrenocortical tissue appears to be more sensitive since it does not have the capacity to detoxify or metabolize the drug to the extent occurring in liver and kidney.
The influence of organic ligands on the retention of lead in soil.

Abstract Organic acids are commonly produced and exuded by plant roots and soil microorganisms. Some of these organic compounds are effective chelating agents and have the potential to enhance metal mobility. The effect of citrate and salicylate on the leaching of lead in soil was investigated in a laboratory experiment. In short-term batch experiments, adsorption of lead to soil was slightly enhanced with increasing salicylate concentration (500–5000 μM) but decreased significantly in the presence of citrate. These observations suggested that citrate may enhance Pb leaching, but this was not observed in the column study. Soluble Pb in the presence and absence citrate or salicylate (up to 5000 μM) was added to soil columns at a moderate flow rate, but no Pb was observed to emerge from the soil in any of the soil columns. Rapid biodegradation of citrate in soil eliminated potential complexing ability. Breakthrough of Pb from soil was noted only when using small columns at high flow rates (>20 pore volumes per day). Under these conditions of physical and chemical non-equilibrium, citrate was not degraded and significantly enhanced Pb mobility. As in the batch adsorption experiments, the presence of salicylate reduced Pb leaching. Considering the extreme conditions required to induce Pb leaching, it is likely that Pb will remain relatively immobile in soil even in the presence of a strong complexing agent such as citrate.
Natural food requirements of the large milkweed bug, Oncopeltus fasciatus (Hemiptera: Lygaeidae), and their relation to gregariousness and host plant morphology

The life ofOncopeltus fasciatus centers on the seeds of milkweeds (Asclepiadaceae,Asclepias syriaca in this study). Adults reproduce prolifically on these seeds, but they engage in only half as much copulation and lay only a few eggs when fed milkweed buds and flowers instead. They can not maintain body weight on a diet of just vegetative plants. Vegetative shoots support only slow growth and produce adults only in certain circumstances. Seeds are often inaccessible to nymphs in the three youngest instars, since their mouthparts are too short to penetrate the thick walls ofA. syriaca pods. Nymphs feeding from the outside of closed pods develop more slowly than those feeding on exposed seeds. Since mortality occurs at a constant rate, slow growth results in fewer surviving. Even adults, which can feed through almost any pod wall, prefer to feed where it is thinnest. Thus the pod wall effectively protects many seeds from this herbivore. Nymphs in larger groups (20 individuals) suffer much lower mortality than those in small groups (5 individuals), when they are feeding from the outside of closed pods. However, group size does not affect survival when nymphs are fed seed. Gregariousness apparently partly compensates for the less nutritious diet attainable from the outside of pods and thus is related to this bug's extreme specialization of diet. Other characteristics coordinated with the seed requirement include the timing of migration and egg laying, the female's choice of oviposition site, and the nymphs' balanced tendencies to be sedentary and to disperse. Among the milkweeds, such traits as thick pod walls, wide spacing, and rapid seed dispersal could have been selected for by a seed predator such asO. fasciatus. As a specialist and a probable agent of such selection,O. fasciatus is committed to keeping up with changes in its host plant. This requires maintaining some flexibility in its behavior or gene pool. K. Evans (personal communication) finds thatO. fasciatus in California onA. fascicularis lays eggs so early that the first nymphs hatch as the first flowers are opening. In that more equitable climate and on that host, adult reproduction is apparently not as dependent on pods being present in the colonized patch, and the nymphs must rely on non-seed food more often than they do in the association withA. syriaca in the East and Midwest. This very specialized species apparently retains enough adaptability to exploit milkweeds of various forms and phenologies living in a wide range of climates. This adaptability could promise its continued success in the coevolutionary race with its host plants.
ELECTROSTATIC CHARACTERIZATION OF ENZYME COMPLEXES : EVALUATION OF THE MECHANISM OF CATALYSIS OF DIHYDROFOLATE REDUCTASE

The catalytic mechanism of dihydrofolate reductase is evaluated with Poisson−Boltzmann electrostatic and quantum chemical vibrational frequency calculations. The results indicate that an elevated pKa of 6.5 associated with the chemical step is due to the formation of the enol tautomer of the substrate's pterin ring. The tautomer is induced to form as a result of substrate binding, in which the substrate desolvates the active site and binds to the carboxylate of Asp 27. Although the binding reaction is favorable, burial of the negative charge on Asp 27 is not. Protonation of Asp 27 occurs, concerted with tautomerization of the substrate, resulting in active site electrical neutrality and activation of the substrate for catalysis. These results require a reinterpretation of previous data from Raman spectroscopy studies in which it was proposed that the reactive atom, the pterin N5, is directly protonated. Quantum chemical vibrational frequency calculations demonstrate that the enol tautomer undergoes a Rama...
Changes in intracellular free amino acids in tissues of the caged mussel, Elliptio complanata , exposed to contaminated environments

Intracellular tissue concentrations of free amino acids (FAA) were monitored in caged mussels (Elliptio complanata) exposedin situ for 27–29 days and 77–79 days in the Yamaska River watershed (Quebec, Canada). Total concentrations of FAA (nmol/mg wet weight) increased in both mantle and adductor muscle tissue at several sites impacted by agricultural runoff and urban effluent from municipal sewage and light industries when compared to levels in mussels located at a site with little anthropogenic impact. Consistent changes in the per cent composition of individual FAA to the total FAA pool included decreases in serine, threonine, glycine and valine as well as increases in glutamic acid and glutamine at 27–29 days but results were not consistent with longer exposure and varied amongst sites. Few changes in total or individual FAA were observed in gill tissue. The results suggest that increases and/or decreases in total FAA in some tissues of freshwater bivalves may be indicative of generalized stress induced by a variety of environmental factors and may be useful as anin situ biochemical index of toxicity.
Leaving flatland: Diagnostics for Lagrangian coherent structures in three-dimensional flows

Abstract Finite-time Lyapunov exponents (FTLE) are often used to identify Lagrangian Coherent Structures (LCS). Most applications are confined to flows on two-dimensional (2D) surfaces where the LCS are characterized as curves. The extension to three-dimensional (3D) flows, whose LCS are 2D structures embedded in a 3D volume, is theoretically straightforward. However, in geophysical flows at regional scales, full prognostic computation of the evolving 3D velocity field is not computationally feasible. The vertical or diabatic velocity, then, is either ignored or estimated as a diagnostic quantity with questionable accuracy. Even in cases with reliable 3D velocities, it may prove advantageous to minimize the computational burden by calculating trajectories from velocities on carefully chosen surfaces only. When reliable 3D velocity information is unavailable or one velocity component is explicitly ignored, a reduced FTLE form to approximate 2D LCS surfaces in a 3D volume is necessary. The accuracy of two reduced FTLE formulations is assessed here using the ABC flow and a 3D quadrupole flow as test models. One is the standard approach of knitting together FTLE patterns obtained on adjacent surfaces. The other is a new approximation accounting for the dispersion due to vertical ( u , v ) shear. The results are compared with those obtained from the full 3D velocity field. We introduce two diagnostic quantities to identify situations when a fully 3D computation is required for an accurate determination of the 2D LCS. For the ABC flow, we found the full 3D calculation to be necessary unless the vertical ( u , v ) shear is sufficiently small. However, both methods compare favorably with the 3D calculation for the quadrupole model scaled to typical open ocean conditions.
Methodology for Environmental Sustainability Evaluation Of Airport Development Alternatives

This study develops a new approach for the evaluation of greener airport systems. The proposed concepts demonstrate how to implement greener practices from the early stages of an airport infrastructure project in an economically rational and stakeholder-focused manner. Objectives of the proposed methodology are two-fold: 1 to promote greener design practices among airport planners, designers, and managers, and 2 to institute active communication among all airport stakeholders. The study contributes to the state of the knowledge in airport environmental management by proposing the combination of five distinct considerations: 1 the evaluation of environmental sustainability with a focus on the planning and design stages of airport facilities, 2 a procedure for screening and ranking alternatives, 3 examples of applicable performance criteria, objectives and indicators with sample scoring procedures, 4 a Multi-Criteria Decision Making MCDM approach combined with cost and utility functions, and 5 a flexible implementation strategy to enable end-users to adjust the complexity of the evaluation. This study is intended to open a discussion for the development of a methodological tool that fulfills aims of promoting greener airport design, while at the same time satisfactorily addressing stakeholder concerns.
Generalized proportional-plus-derivative compensators for a class ofuncertain plants

Controller design for a class of systems consisting of a positive-real transfer function P(s) followed by an integrator is considered. A generalized proportional-plus-derivative compensator is proposed for robustly stabilizing a class of uncertain plants represented by a positive-real transfer function followed by an integrator. The novel feature of the proposed compensator is that the proportional and rate gains used are transfer functions rather than constants, which allows more design freedom and offers the potential for better performance with guaranteed robust stability. The results obtained are for single-input/single-output systems. If the results are extended to the multivariable case, they will then be applicable to realistic flexible spacecraft.
Explicit algebraic scalar-flux models for turbulent reacting flows

Explicit algebraic scalar-flux models that are valid for three-dimensional turbulent flows are derived from a hierarchy of second-order moment closures. The mathematical procedure is based on the Cayley–Hamilton theorem and is an extension of the scheme developed by Taulbee. Several closures for the pressure–scalar gradient correlations are considered and explicit algebraic relations are provided for the velocity–scalar correlations in both nonreacting and reacting flows. In the latter, the role of the Damkohler number is exhibited in isothermal turbulent flows with nonpremixed reactants. The relationship between these closures and traditional models based on the linear gradientdiffusion approximation is theoretically established. The results of model predictions are assessed by comparison with available laboratory data in turbulent jet flows.
Differential cytopathogenicity accompanying Mycoplasma pneumoniae infection of human lung fibroblasts maintained in newborn bovine serum or fetal bovine serum.

MRC-5 human lung fibroblasts maintained in Eagle's basal medium (BME) with either 10% fetal bovine serum (FBS) or 10% newborn bovine serum (NBS) did not respond identically to infection byMycoplasma pneumoniae. Fibroblasts grown in NBS did not develop any cytopathic effect (CPE) when infected withM. pneumoniae, whereas those maintained in FBS developed a pronounced CPE. There was also a difference in sensitivity to infection for fibroblasts maintained in the two sera before the infection. Fibroblasts maintained in NBS, then transferred to FBS 48 h before infection, were still less sensitive toM. pneumoniae infection than cells maintained constantly in FBS.Mycoplasma pneumoniae attached comparably to the fibroblasts grown in the two sera, so the differences in CPE development could not be attributed to differences in mycoplasma attachment. Measurements of DNA, RNA, and protein syntheses of the fibroblasts grown in NBS and FBS indicate that the cells in NBS were growing more rapidly than those in FBS. A determination of the doubling times shows that the doubling time of cells in NBS was 44 h, whereas that of cells in FBS was 51 h. Polyacrylamide gel electrophoresis of samples of NBS and FBS showed significant differences in serum protein composition. The NBS had several protein bands that were lacking in the FBS. This study demonstrates the importance of serum effects in the study ofM. pneumoniae infection.
Occurrence of progressive DNA damage coincident with the appearance of foci of altered hepatocytes

The technique of alkaline elution was used to evaluate alterations in nuclear DNA obtained from livers of rats that had received a single 6.6 mg/kg dose of diethylnitrosamine (DEN) during liver regeneration and subsequent exposure (7 days after partial hepatectomy) to phenobarbital (BP). DNA from normal and regenerating liver demonstrated a significant increase in the rate of elution following DEN administration. In those DEN-treated groups that did not receive PB, the rate of DNA elution decreased slowly but failed to return to normal by 44 weeks. Exposure to PB hastened recovery of a normal DNA elution profile in normal liver following DEN treatment, by 44 weeks, DNA from these rats eluted at a normal rate. However, in rats treated with DEN during liver regeneration, the rate of DNA elution began to increase at 28 weeks of PB exposure and became progressively more rapid through the 36th and 44th weeks. This latter group also demonstrated foci of gamma-glutamyl-transferase (GGT)-positive hepatocytes at 28 weeks of PB exposure that increased in number and size concomitantly with the increasing rate of DNA elution. AT 44 weeks, one or more primary hepatocellular carcinomas were present in 73% of the rats in this group; none was seen in any other group. Foci of GGT positive hepatocytes, an increasing rate of DNA elution and eventual primary hepatocellular carcinoma were seen in a group of rats that was begun on PB as late as 85 days after partial hepatectomy and DEN treatment.
Brief communication: Cardiovascular screening practices of major North American professional sports teams.

This survey of practices of 122 professional sports teams in North America found that team physicians always perform history taking and physical examinations, usually perform electrocardiography (9...
Effect of uridine coadministration on 5'-deoxy-5-fluorouridine disposition in rats.

Uridine (UR) inhibits the metabolic activation of 5′-deoxy-5-fluorouridine (dFUR) to 5-fluorouracil (FU) by the intestinal pyrimidine nucleoside phosphorylases and could potentially reduce its intestinal toxicity. This study examined the effect of UR coadministration on the absorption and disposition of an oral dose of dFUR. Rats were given dFUR alone (500 mg kg-1) and dFUR (300 mg kg-1) plus UR (4.5 g kg-1) in a random crossover experiment. Simultaneous injection of a tracer dose of [6-3H]dFUR was used to asses the total body clearance (Cl) of dFUR. The absorption of UR was rapid and variable. The UR dose produced a maximal blood concentration of 80 μg/ml for UR and 100 μg/ml for its metabolite uracil (U). The absorption of dFUR was slower than UR, as indicated by its later time of maximal concentration. UR did not alter the Cl of dFUR, but reduced the absorption rate of dFUR from the gastrointestinal tract and significantly reduced the absolute oral bioavailability of dFUR from 55.2% to 33.4%. The effects of UR coadministration on the dFUR metabolite FU were opposite to those on dFUR; the FU availability was increased sixfold, and the elimination of FU was reduced. Based on the known competition between pyrimidine bases for their saturable metabolic enzymes, the increase in FU availability by UR coadministration was likely due to a competitive inhibition of FU metabolism by U. This study established the complex pharmacokinetic interactions between dFUR and UR and between their metabolites, which may be important in the modulation of dFUR activity by UR.
Acute NO2 exposure alters inflammatory cell activation and particle clearance in silica-injected mice.

Previous work indicates that exposure to nitrogen dioxide (NO2) at different stages of silica‐induced acute inflammation alters the outcome of lung injury. C57BI/6 mice were injected intratracheally (IT) with 2.0 mg silica particles (SI) and subsequently exposed to 20 ppm NO2 (or filtered air) within 2 or 24 h after SI. The present study demonstrates that exposure of mice to NO2 within 2 h after silica injection during acellular lung injury (increased alveolar protein, albumin, lactate dehydrogenase) resulted in increases in intraalveolar and inter‐stitial polymorphonuclear leukocytes (PMNs) as well as more advanced granulomas on d 14, 30, and 60. In contrast, exposure of mice to NO2 24 h after silica during marked lung injury and inflammatory cell influx resulted in a less severe inflammatory reaction with fewer interstitial and alveolar PMNs and decreased size and number of pulmonary granulomas. NO2 exposure 2 or 24 h after SI appeared to increase in the lavage fluid levels of lysosomal enzymes and at t...
Vibrotactile threshold is elevated in temporomandibular disorders

Experimental pain can elevate vibrotactile threshold, a phenomenon attributed in the literature to the operation of a 'touch gate.' It is not known, however, whether clinical pain produces similar effects. To explore this possibility, we measured vibrotactile threshold in patients with temporomandibular disorders (TMD) whose pain had a prominent myalgic component. Two-interval forced-choice tracking was used to determine threshold for a 25-Hz vibratory stimulus presented on the cheek. Threshold was found to be significantly elevated in the TMD group, compared to an age- and gender-matched control group of pain-free individuals. Within the TMD group, those with a supra-median level of muscle tenderness (corrected for background levels of spontaneous pain) had significantly higher threshold than those with lower levels of palpation pain. These findings are consistent with the idea of a touch gate, and suggest the usefulness of further research in this area with clinical pain populations. The effects of an adapting stimulus (25 Hz, 20 dB SL) were also studied, and found to produce parallel elevations in vibrotactile threshold in the TMD and pain-free groups. This result indicates that at least some adaptation occurs at a higher (subsequent) level of somatosensory information processing than does the touch gating implied by the unadapted thresholds.
Flexible supply policy with options and capacity constraints

This paper considers a class of multi-period flexible supply policies with options and capacity constraints. The main results are to characterize the optimal ordering and purchasing options policy and the minimum expected cost in a period and thereafter under the assumptions about the options and ordering quantities.
Potential-Dependent Surface-Enhanced Raman Scattering from Adsorbed Thiocyanate for Characterizing Silver Surfaces with Improved Reproducibility:

Surface-enhanced Raman scattering (SERS) spectroelectrochemistry is used to characterize electrochemically roughened and highly polished polycrystalline silver SERS-active substrates. Changes in the nitrile stretching vibrational mode of adsorbed thiocyanate are used as an in situ spectroscopic probe: the potential dependence of band position (Stark tuning), shape, and scattering intensity of this mode are measured in order to investigate differences between SERS-active sites found on smooth and roughened electrode surfaces. Results obtained from thiocyanate adsorbed onto two different types of highly polished Ag surfaces (alumina and diamond polishing) show discrete populations of SERS-active adsorption sites that remain stable over a wide potential range. This behavior stands in contrast to that observed on electrochemically roughened surfaces, where very strong Stark tuning, large vibrational bandwidths, and irreversible loss of SERS enhancement upon negative potential excursions can be attributed to a diverse population of labile SERSactive sites that exhibit strong charge-transfer interactions with the adsorbate and large chemical SERS enhancement.
On Identifying Transfer Functions and State Equations for Linear Systems

Two methods are established for identifying constantcoefficient C2n-type noise-free linear systems if the time response data of the input-output or of all states are known. 2n response data are required to identify an nth-order transfer function or state equation for an unknown linear system. The order of the unknown system can be identified by checking a sequence of determinants. The Z transform and its inversion are mainly used.
Transformation of isotactic polypropylene droplets from the mesophase into the α-phase

The structural transformation of homogeneously nucleated metastable mesophase of polypropylene (PP) particles was investigated in this study. We demonstrated the formation of heterogeneity-free mesophase by slow cooling of the droplets unlike mesophase formation by quenching of the PP melt, which contained large number of bulk nuclei. Submicron size PP droplets were produced by thermal break up of PP and polystyrene layered film assembly. When cooled from melt, the PP droplets crystallized into mesophase at 44 °C revealing granular morphology. Subsequent heating thermogram of the PP particles showed a broad exotherm, which was attributed to the transformation of mesophase into α-phase. This transformation was investigated during heating by annealing the PP particles at different temperatures. Annealed PP particles were analyzed by means of thermal, morphological and structural properties measurements. Results revealed a two step process for the transformation process. In the first step, the internal rearrangement of PP chains, as against melting and recrystallization of the mesophase, was observed. Since granular morphology was not affected significantly up to 120 °C, it was suggested that translational and rotational motions of PP helices produced ordered α-phase. In the second step, increment in grain size distribution was observed, when the droplets were annealed at 140 °C. The results were attributed to enhanced chain mobility and merging of the grain boundaries. Annealing at 160 °C revealed the formation of short lamellar structures. Crystal thickening, melting and recrystallization of α-phase were suggested at high temperature annealing. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011
Physiology and cardiovascular effect of severe tension pneumothorax in a porcine model.

Abstract Background Pneumothoraces are relatively common among trauma patients and can rapidly progress to tension physiology and death if not identified and treated. We sought to develop a reliable and reproducible large animal model of tension pneumothorax and to examine the cardiovascular effects during progression from simple pneumothorax to tension pneumothorax. Materials and methods Ten swine were intubated, sedated, and placed on mechanical ventilation. After a midline celiotomy, a 10-mm balloon-tipped laparoscopic trocar was placed through the diaphragm, and a 28F chest tube was placed in the standard position and clamped. Thoracic insufflation was performed in 5-mm increments, and continuous cardiovascular measurements were obtained. Results Mean insufflation pressures of 10 mm Hg were associated with a 67% decrease in cardiac output (6.6 L/min versus 2.2 l/min; P = 0.04). An additional increase in the insufflation pressure (mean 15 mm Hg) was associated with an 82% decrease in cardiac output from baseline (6.8 versus 1.2 L/min; P P P = 0.06), with the central venous pressure and pulmonary artery diastolic pressure approaching equalization immediately before the development of major hemodynamic decline. Pulseless electrical activity arrest was induced at an average of 20 mm Hg. Tension physiology was immediately reversible with adequate decompression, allowing for multiple repeated trials. Conclusions A reliable and highly reproducible model was created for severe tension pneumothorax in a large animal. Major cardiovascular instability proceeding to pulseless electrical activity arrest with stepwise insufflation was noted. This model could be highly useful for studying new diagnostic and treatment modalities for tension pneumothorax.
Combinatorial individual differences scaling within the city-block metric

A new method is proposed for conducting individual differences scaling within the city-block metric that does not rely on gradient- or subgradient-based optimization. Instead, a combinatorial optimization scheme is utilized for identifying object coordinates minimizing the least-squares loss function. The illustrative application of combinatorial individual differences scaling within the city-block metric to schematic face stimuli suggests that the new method offers a promising alternative to gradient-based attempts for fitting city-block scaling models, which suffer from the well-documented difficulty of local minima.
Formation Damage and Treatment of Offshore Water Disposal Wells in Saudi Arabia: Case Studies

In one Saudi Aramco offshore oil field, the formation fluids are being produced from different platforms and transported to one onshore gas-oil separation plant (GOSP) where the produced water is removed from the hydrocarbon stream. The produced water is injected back to highly permeable formations through disposal wells with no interruption. In this way, the water disposal system is an integral part of the hydrocarbon recovery system. A failure of one of the disposal wells could adversely affect oil production. Saudi Aramco petroleum engineers are placing more and more attention on water disposal wells as a higher volume of produced water from the increasing hydrocarbon production rates has to be disposed of continuously every day. The primary objective of surveillance on the disposal wells is to keep an extra disposal capacity for continuous oil production from the field and to precisely monitor the decline rate of the capacity of each disposal well. A real sweep efficiency and pressure maintenance are not the surveillance scope for water disposal wells in our case. Few technical papers have been published that discuss the problems a water disposal system may have in a matured field and address issues such as surveillance of well performance and water quality, formation damage mechanisms, treatment and so forth. In this paper, the existing water disposal system in a matured offshore oil field is briefly described and discussed with the surveillance of well performance and the quality disposal water, potential problems, and the evolution of the surveillance philosophy. The reasons why most disposal wells experienced severe injection decline are analyzed and discussed in detail. Historic treatments were summarized with actual outputs demonstrating “ineffective” treatments for the issues discussed. After several trial tests, one customized chemical treatment recipe was developed to effectively tackle the issues and actual well data is included showing the effectiveness of those treatments. A new surveillance strategy for better monitoring of well performance and the quality of “waste” fluid is also discussed in this paper. It can be concluded from our work that formation damage exists extensively in wastewater injection wells and that it greatly influences the performance of disposal wells. Any treatment for restoring the injection capacity of water disposal wells impaired by low quality water is expensive. Any successful treatment is rooted into the detailed analysis of the problems. Implementation of a proper surveillance program and appropriate processing of the injection fluid is also vitally important for wastewater management.
Der Einfluß von Silikaten auf die Wirksamkeit verdünnter, wässeriger Waschmittel zur Bildung thermodynamisch stabiler Kolloidlösungen sonst unlöslicher Farbstoffe

Es wurde gezeigt, das nicht nur einige kolloide Losungen thermodynamisch ebenso stabil sind wie echte Losungen, sondern das sie die Eigenschaft besitzen, in Wasser unloslichen Farbstoff in einem bestimmten Ausmase aufzulosen oder ihn aus einer Losung eines nichtwasserigen Losungsmittels zu extrahieren. Dieser Vorgang fuhrt zu einem echten, reversiblen Gleichgewicht, welches von beiden Seiten erreicht werden kann und von der Vorbehandlung oder Vorgeschichte des Systems unabhangig ist.
Astrocytes Directly Influence Tumor Cell Invasion and Metastasis In Vivo

Brain metastasis is a defining component of tumor pathophysiology, and the underlying mechanisms responsible for this phenomenon are not well understood. Current dogma is that tumor cells stimulate and activate astrocytes, and this mutual relationship is critical for tumor cell sustenance in the brain. Here, we provide evidence that primary rat neonatal and adult astrocytes secrete factors that proactively induced human lung and breast tumor cell invasion and metastasis capabilities. Among which, tumor invasion factors namely matrix metalloprotease-2 (MMP-2) and MMP-9 were partly responsible for the astrocyte media-induced tumor cell invasion. Inhibiting MMPs reduced the ability of tumor cell to migrate and invade in vitro. Further, injection of astrocyte media-conditioned breast cancer cells in mice showed increased invasive activity to the brain and other distant sites. More importantly, blocking the preconditioned tumor cells with broad spectrum MMP inhibitor decreased the invasion and metastasis of the tumor cells, in particular to the brain in vivo. Collectively, our data implicate astrocyte-derived MMP-2 and MMP-9 as critical players that facilitate tumor cell migration and invasion leading to brain metastasis.
Familial nephrosis, nerve deafness, andhypoparathyroidism

Two male siblings with nephrotic syndrome, nerve deafness, and hypoparathyroidism are described. Eachchild, one at five years of age and the other at eight years, died in renal failure. At autopsy the parathyroid glands were absent in one child and hypoplastic in the other one. Two twin male siblings presented with similar findings and died at the age of three years. At autopsy their parathyroid glands were fibrotic, and glomerular basement membranes were thickened. This may be the first recorded association of familial nephrosis, nerve deafness, and hypoparathyroidism. The mode of transmission is compatible with autosomal recessive inheritance.
Phase synchronization of foot dynamics in quiet standing.

Abstract This study was set-up to investigate the effect of mechanical constraints arising from different postural stances on the AP and ML pattern of the time evolutionary properties of phase synchronization of the foot dynamics, together with their relation to the dynamics of COP NET . The results showed that postural stance differentially influenced the phase synchronization (number and duration of the epochs) between the individual feet COPs and of each foot to the COP NET . The side-by-side stance had longer phase synchronization duration in the anterior–posterior (AP) direction and shorter duration in the medial–lateral (ML) direction than the staggered and tandem postures. In the staggered and tandem postures, the relative phase between the rear foot COP and the COP NET had longer phase synchronization than the relative phase between the COPs of the two feet and that between the front foot COP and the COP NET . The time evolutionary properties of the feet coupling dynamics revealed patterns of “stable” but “flexible” control of the postural system as a function of the asymmetrical foot loading in the stance.
How Women in Late Midlife Become Caregivers for Their Aging Parents

Approximately 52 million Americans provide informal (unpaid) care to a family member or friend who is disabled or ill. The most common informal caregiving relationship is that of an adult child providing assistance to an aging parent. This article describes a qualitative study examining how adult daughters between the ages of 50 and 65 become caregivers to their parent or parent-in-law. Data were collected through in-depth, face-to-face interviews with 15 female caregivers. Analysis revealed that assistance provided to parents was initiated by one or more triggering event, after which participants became caregivers in either an emergent or deliberate manner.