cssi/SciSciGPT-SciSciNet huggingface dataset:
Intercalated Organic−Inorganic Perovskites Stabilized by Fluoroaryl−Aryl Interactions

Crystals of several new hybrid tin(II) iodide-based perovskites, involving 2,3,4,5,6- pentafluorophenethylammonium or phenethylammonium cation bilayers and intercalated aryl or perfluoroaryl molecules, were grown by slow evaporation of a methanol solution containing the hybrid perovskite and the intercalating species. The (C6F5C2H4NH3)2SnI4·(C6H6) structure was solved at −75 °C in a monoclinic C2/c subcell [a = 41.089(12) A, b = 6.134(2) A, c = 12.245(3) A, β = 94.021(5)°, Z = 4] and consists of sheets of corner-sharing distorted SnI6 octahedra separated by bilayers of pentafluorophenethylammonium cations. The intercalated benzene molecules form a single well-ordered layer interposed between adjacent fluoroaryl cation layers. The corresponding hybrid with an unfluorinated organic cation and fluorinated intercalating molecule, (C6H5C2H4NH3)2SnI4·(C6F6), is isostructural [a = 40.685(4) A, b = 6.0804(6) A, c = 12.163(1) A, β = 93.136(2)°, Z = 4]. For each intercalated system, close C···C contacts (3.44−3.50 ...
A precise uranium assay using solvent extraction and spectrophotometry

The uranium spectrophotometric measurement using the uranylnitrate-quaternaryamine solvent extraction method is investigated to identify factors that affect precision and accuracy of the uranium determination. The inherent spectrophotometric precision was measured with neutral density filters in the sample light path and was found to be <0.1% relative standard deviation (RSD). Under selected experimental conditions, temperature instability has a −0.02% effect on the extraction, and a −0.4% effect on the absorbance of the uranium extract in 2-nitropropane (2-NP) or methyl isobutyl ketone (MIBK) solvents. Under optimum conditions at the 10 mg uranium level, RSDs of ∼0.1% resulted.
The effect of private tubewells on income and income inequality in rural Pakistan

Summary Since the introduction of private tubewells in rural Pakistan, farmers have increasingly used groundwater to supplement canal water for irrigation and improve the reliability of the water supply. Farmers obtain groundwater either from their own tubewells or from other well owners. This paper examines the effect of private tubewells on rural income, both in terms of income level and income distribution since it may differ across farmers with different irrigation status (only canal water, canal water and groundwater from own tubewell, and canal water and purchased groundwater). The results show that private tubewells work to enhance rural income and reduce income inequality in rural Pakistan.
Reversal of androgen inhibition of estrogen-activated sexual behavior by cholinergic agents.

Abstract Androgens have been found to inhibit lordosis activated by estrogen treatment of ovariectomized female rats. In the present experiments, dihydrotestosterone propionate (200 μg for 3 days) inhibited the incidence of lordosis in ovariectomized females treated with estradiol benzoate (1 μg for 3 days). This inhibition of lordosis was reversed 15 min after bilateral intraventricular infusion of physostigmine (10 μg/cannula), an acetylcholinesterase inhibitor, or carbachol (0.5 μg/cannula), a cholinergic receptor agonist. This reversal of inhibition appears to be mediated by cholinergic muscarinic receptors since pretreatment with scopolamine (4 mg/kg, ip), a muscarinic receptor blocker, prevented the reversal of androgen inhibition by physostigmine. These results indicate that androgens may inhibit estrogen-activated lordosis through interference with central cholinergic muscarinic mechanisms.
Development of “substrate-trapping” mutants to identify physiological substrates of protein tyrosine phosphatases

The identification of substrates of protein tyrosine phosphatases (PTPs) is an essential step toward a complete understanding of the physiological function of members of this enzyme family. PTPs are defined by a conserved catalytic domain harboring 27 invariant residues. From a mutagenesis study of these invariant residues that was guided by our knowledge of the crystal structure of PTP1B, we have discovered a mutation of the invariant catalytic acid (Asp-181 in PTP1B) that converts an extremely active enzyme into a “substrate trap.” Expression of this D181A mutant of PTP1B in COS and 293 cells results in an enzyme that competes with endogenous PTP1B for substrates and promotes the accumulation of phosphotyrosine primarily on the epidermal growth factor (EGF) receptor as well as on proteins of 120, 80, and 70 kDa. The association between the D181A mutant of PTP1B and these substrates was sufficiently stable to allow isolation of the complex by immunoprecipitation. As predicted for an interaction between the substrate-binding site of PTP1B and its substrates, the complex is disrupted by vanadate and, for the EGF receptor, the interaction absolutely requires receptor autophosphorylation. Furthermore, from immunofluorescence studies, the D181A mutant of PTP1B appeared to retain the endogenous EGF receptor in an intracellular complex. These results suggest that the EGF receptor is a bona fide substrate for PTP1B in vivo and that one important function of PTP1B is to prevent the inappropriate, ligand-independent, activation of newly synthesized EGF receptor in the endoplasmic reticulum. This essential catalytic aspartate residue is present in all PTPs and has structurally equivalent counterparts in the dual-specificity phosphatases and the low molecular weight PTPs. Therefore we anticipate that this method may be widely applicable to facilitate the identification of substrates of other members of this enzyme family.
Rapid isolation of desired sequences from lone linker PCR amplified cDNA mixtures: application to identification and recovery of expressed sequences in cloned genomic DNA.

A simple and efficient method for the rapid isolation of specific sequences from PCR-amplified cDNA mixtures has been developed. cDNA mixtures obtained using lone linker PCR (Ko et al. 1990) appeared to be highly representative even though the starting material, 100 ng-2 μg of total RNA, is much less than is required for making an ordinary cDNA library. With this method, cDNA mixtures were obtained from limited materials, including early mouse embryos and primordial germ cells. For selective enrichment of desired cDNAs, biotinylated probe was hybridized with the lone linker-linked cDNA in solution and the resulting probe-cDNA hybrid was captured by Streptavidin-coated magnetic beads. After appropriate washing, cDNA was released from the beads and subjected to amplification followed by cloning into a vector. Using genomic fragments isolated during chromosomal walking in the T/t complex of mouse Chromosome (Chr) 17, cDNAs encoding novel germ cell specific genes have been readily isolated by the above procedures. The method, termed random access retrieval of genetic information through PCR (RARGIP), will streamline the entire process from RNA to cDNA greatly. Its application potentials in various areas of molecular genetics will be discussed.
Soft tissue sarcomas of childhood.

The soft tissue sarcomas are a heterogeneous group of neoplasms that arise from primitive mesenchymal cells throughout the body. Population-based data from the Surveillance, Epidemiology and End Results (SEER) program of the National Cancer Institute suggest that these tumors account for approximately 7% of all cancer cases in patients under the age of 20 years, with nearly 900 cases reported annually. Traditionally, pediatric oncologists have arbitrarily divided these tumors into two groups: rhabdomyosarcoma (RMS), the most common soft tissue sarcoma of childhood, and non-RMS soft tissue sarcomas (NRSTS), a biologically and clinically heterogeneous assortment of tumors. The most common NRSTS in childhood are synovial sarcoma, malignant fibrous histiocytoma, malignant peripheral nerve sheath tumor, and fibrosarcoma.1–4 RMS is more common in children less than 10 years of age, whereas the NRSTS predominate in the older age groups (Fig. 1).
CULTURAL DIFFERENCES IN MEASURING EDUCATIONAL ACHIEVEMENT: A CHALLENGE TO PSYCHOLOGY

Abstract Les differences culturelles dans la mesure de la reussite scolaire: un probleme pour les psychologies. - La “culture educative”, c'est-a-dire le systeme standard de formation et d'evaluation, peut varier considerablement d'un pays a l'autre. La recherche interculturelle devrait utiliser les decouvertes faites par la psychologie experimentale en matiere de processus d'apprentissage pour resoudre les problemes de l'evaluation des niveaux d'instruction. Les compa- raisons interculturelles portant sur l'intelligence et la reussite scolaire doivent prendre en consideration les differences qui se manifestent dans l'acquisition des capacites particulieres impliquees dans les tests. C'est ainsi, par exemple, qu'une comparaison experimentale d'etudiants americains et israeliens portant sur la retention d'un materiel symbolique et d'un materiel significatif, et utilisant un test subjectif de reconstruction (ecrire un essai) et un test objectif de reconnaissance a choix multiple, a fait appara[icaron]tre un...
A larger and more turbulent Universe

THE modern version of the Hubble diagram in which the log of the redshift is plotted against apparent magnitude corrected for redshift and absorption effects of clusters of galaxies, is in principle capable of yielding several cosmologically useful pieces of information. In this letter I report evidence for a significant and substantial departure from the expected redshift for the Virgo cluster of galaxies. A peculiar velocity of 658 ± 96 km s−1 is derived but because of Virgo's membership in the Local Supercluster, such a value is not unexpected. Thus the turbulence recently observed by Smoot et al.1 for the Galaxy's motion within the Hubble expansion is present elsewhere in the Universe as well. Because the Virgo cluster does not exactly follow the Hubble law, a new value for the Hubble constant equal to 43.4 ± 2.6 km s−1 Mpc−1 is found leading to an observable Universe 1/4 to 1/3 again as large as was previously recognised.
Physics in the GeV Region with Polarized Targets in Electron Storage Rings

During the past five years interest in the internal target method for electron storage rings has intensified. At present there is an active internal target program at the VEPP-3 ring in Novosibirsk and a second ring (NEP) dedicated for nuclear physics is under construction. An internal Ar jet target is in use at the ADONE ring in Frascati in order to produce tagged photons. In addition, plans are being made for an internal target program at the 300-MeV electron ring at Saskatoon. Construction of electron rings at MIT-Bates and NIKHEF is beginning and both laboratories plan internal target facilities. Finally, there are discussions with regard to the PEP and HERA rings for internal target experiments in the Multi-GeV region.
Wood dust exposure and the association with lung cancer risk.

Background Wood dust was designated as a human carcinogen based on increased sinus and nasal cancer rates among exposed workers. However, data on an association with lung cancer have been inconclusive. Methods Self-reported wood dust exposure was compared between 1,368 lung cancer patients and 1,192 cancer-free adults, in a lung cancer case-control study. Epidemiological information was collected through a detailed personal interview. Results Using several definitions of wood dust exposure we consistently observed statistically significant elevated adjusted risk estimates; for example, the adjusted odds ratio (OR) for combined wood dust related occupations and industries was 3.15 (95% confidence intervals (CI) 1.45–6.86) and for an overall summary exposure measure it was 1.60 (95% CI 1.19–2.14). The association was maintained when stratified by histopathological type. Among those exposed to cigarette smoke and wood dust, 21% of the cases were attributable to biologic interaction. Conclusions Wood dust exposure is a potential risk factor for lung cancer. Am. J. Ind. Med. 47:349–357, 2005. © 2005 Wiley-Liss, Inc.
Experimental evidence of period doubling of tori during an electrochemical reaction

Abstract Chaos and period doubling of tori during copper electrodissolution in acidic chloride solutions are studied. The thickness of a surface film acts as a slowly varying parameter. We present experimental evidence for the sequence one-band chaos, two-band chaos, double torus, torus, limit cycle, and steady state.
Spontaneous Current Sheets in an Ideal Hydromagnetic Fluid

Parker's theory of spontaneous current sheets, or magnetic tangential discontinuities, in electrically perfectly conducting fluids is demonstrated for globally untwisted magnetic fields in the Chandrasekhar-Kendall representation. All the three-dimensional, globally untwisted fields sharing the same flux distribution, fixed at the rigid boundary of the domain, span an infinity of different field topologies, each preserved in a field under the frozen-in condition. The general result is obtained and illustrated that only one of these topologies allows a field to relax into an everywhere continuous force-free state, namely, the potential field uniquely determined by the boundary flux distribution. All other topologies require the field to find a force-free state containing inevitable tangential magnetic discontinuities. This result extends a class of two-dimensional demonstrations of the Parker theory to three dimensions. A field of a fixed topology and boundary flux distribution can be in a continuous state in one equilibrium but may have to contain inevitable tangential discontinuities on transition to another equilibrium. This property, demonstrated here with untwisted fields, is probably the hydromagnetic origin of flares occurring in the course of slow evolution in the solar corona.
Visual free recall.

Lists of complex pictures, not easily encoded verbally, were presented to subjects who recalled them by writing brief descriptions. The lists were 10, 20, and 40 pictures in length. Recall failed to show the primacy and recency effects seen with verbal materials, but was lower for pictures in longer lists. This argues for serial-position effects based in short-term memory and independent list-length effects arising during retrieval from long-term memory.
Air Levels of Volatile Organic Compounds following Indoor Application of an Emulsifiable Concentrate Insecticide

Insecticidal formulations contain volatile inert ingredients that may be responsible for many of the general health complaints associated with indoor applications. Recent indoor air modeling results suggested that the levels of these volatile organic compounds (VOCs) could be high enough to cause health complaints among certain individuals. To confirm these findings, we performed broadcast and perimeter insecticide applications in four identical, unoccupied student apartments at Rutgers University. Passive dosimeters were used to obtain time-weighted average VOC measurements during the 24 h following each application. Levels were consistently higher in the apartments treated with broadcast applications, reflecting the greater amount of material applied by this method. Peak broadcast levels (21 mg/m3) were similar to peak levels generated by the model and were in the range expected to result in health complaints. Peak perimeter levels were approximately two-thirds as high as peak broadcast levels. Both bro...
Anti-heart tissue antibodies during experimental infections with pathogenic and non-pathogenic Trypanosoma cruzi isolates in dogs

Abstract Dogs infected with a pathogenic Trypanosoma cruzi isolate (Tc-O), or a non-pathogenic isolate (Tc-D) developed low antinuclear antibody titers throughout 240 days of infection. Dogs infected with Tc-O, but not Tc-D, produced anti-heart tissue antibodies (as measured by an ELISA) throughout infection. Antibody levels were highest immediately after the acute stage of infection (30 days post-inoculation—DPI) when myocardiocyte destruction was at its greatest. Antibody levels progressively declined by 100 DPI, and were almost undetectable by 240 DPI when Tc-O infected dogs developed dilated cardiomyopathy. On Western blots, the anti-heart tissue antibodies recognized an antigen with the same molecular weights (65 and 61 kDa M r ) recognized by a monoclonal antibody against human β-adrenoceptors. The results suggest that dogs produce antibodies against heart tissue antigens, possibly the β-adrenoceptor, during infection with a pathogenic, but not a non-pathogenic, isolate of T. cruzi .
Nondestructive evaluation needs in fossil fuel power plants

Fossil power plant operating and maintenance cost reduction efforts coupled with changing plant operating modes have rendered traditional approaches to plant component condition assessment inadequate. New NDE techniques are required to meet utility needs in this changing environment. Key attributes of such new techniques will be improved measurement speed and accuracy, reduced preparation requirements, automated data acquisition, and computer-based analysis support. In addition, tools will be required to assist power plant personnel in making the best decisions on what, when, and how to inspect plant components to achieve overall economic objectives.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Low-light carbon balance and shade tolerance in the seedlings of woody plants: Do winter deciduous and broad-leaved evergreen species differ?

An appendix is available for this article which was not included in the print edition of the Journal. The appendix may be found at the rear of the full text, PDF version of the article. A popular conceptual model asserts that shade tolerance is characterized by morphological and physiological traits that enhance the net rate of carbon capture in low light. We tested this model by quantitatively reviewing growth, leaf lifespan, CO2 exchange and morphological data from 76 studies on woody seedlings grown under conditions of low light. Data were placed into three tolerance categories (intolerant, intermediate, tolerant), two light categories (less than 4% and 4–12%) and two leaf phenology categories (broad-leaved evergreen and winter deciduous). For both evergreen and deciduous groups, intolerant species had traits conferring greater growth potential than tolerant species in both light categories. These traits included greater leaf mass ratio, leaf area ratio, specific leaf area and mass-based photosynthetic rates above light compensation. However, in 0–4% light, growth rates were similar for intolerant and tolerant species, because low light together with higher respiration rates for intolerant species limited the expression of their growth potential differences. Deciduous and evergreen intolerant species were similar in many respects. However, both intermediate and tolerant deciduous species had markedly lower leaf mass ratios and higher root mass ratios than intermediate and tolerant evergreen species. In addition, deciduous species and intolerant evergreens must cope with as much as sixfold higher leaf turnover rates than tolerant evergreen species. Thus, rather than maximizing growth rates in low light, tolerant evergreen species minimize biomass loss through long leaf lifespans and low respiration rates. Tolerant deciduous species also minimize biomass losses by minimizing whole-plant respiration rates but they accomplish low biomass turnover though low leaf mass ratio and not low leaf turnover rates. Furthermore, unlike most tropical evergreens, tolerant deciduous species can gain large fractions of their total growing season carbon during short periods when the overstory is leafless and then allocate this carbon to storage (as reflected by high root mass ratios) rather than new leaves. In conclusion, we found no support for the low-light-enhanced carbon capture model of shade tolerance as viewed strictly from the perspective of physiological growth capacity. This can be explained by the disadvantages to net growth and survival of maintaining a high growth potential at low light, because high growth potential results in greater rates of whole-plant respiration, tissue turnover, herbivory and mechanical damage and in decreased storage. Thus, shade tolerance can be characterized by traits that maximize survival and net growth, where net growth includes losses to all agents.
Ordering Work: Blue-Collar Literacy and the Political Nature of Genre

Within complex organizations, people are members of various and sometimes conflicting subgroupings. Texts function between and across these various subgroupings to simultaneously bridge the gap between them (and thus allow joint work to be done) and yet maintain existing structures of power and territory. This study reports observations of blue-collar laboratory technicians using work orders written by engineers. It identifies work orders as a genre that both triggered and concealed the work of the technicians, allowing it to disappear into the work of the engineers. This study has implications for our understanding of the role texts play in coordinating joint work and for our understanding of what it means for texts to be perceived as generic. In particular, it emphasizes the political aspects of genre as form of social action, an aspect previous research and theory have tended to neglect.
Fatty acid effect on hydroxypropyl methylcellulose-beeswax edible film properties and postharvest quality of coated 'Ortanique' mandarins.

The objective of this work was to investigate the effect of fatty acid (FA) type and content on mechanical properties, water vapor permeability and oxygen permeability of hydroxypropyl methycellulose (HPMC)−beeswax (BW) stand-alone edible films. The effect of these films formed as coatings on the postharvest quality of ‘Ortanique’ mandarins was also studied. Selected FAs were stearic acid (SA), palmitic acid (PA), and oleic acid (OA), using BW/FA ratios of 1:0.5 and 1:0.2 (w/w). HPMC-BW coatings reduced weight and firmness loss of ‘Ortanique’ mandarins, without compromising flavor quality compared to uncoated mandarins. Coatings containing OA provided the best weight loss control at both concentrations tested; however, when the BW/OA ratio was 1:0.5, the coatings increased fruit internal CO2, ethanol, and acetaldehyde contents of ‘Ortanique’ mandarins, therefore reducing flavor compared to the rest of the coatings studied. Although barrier and mechanical properties might be used to understand coating perf...
Microwave spectrum, structure, and barrier to internal rotation of acetone ☆

Abstract The microwave spectrum of (CH3)2CO has been reinvestigated and the spectra of two additional isotopic species, (13CH3)2CO and (CH3)3C18O, have been observed and assigned. These data together with data previously reported for (CD3)2CO are used to calculate a structure based on the assumption of a symmetrical methyl group. The rs structural parameters obtained are: CC = 1.507 A CCC = 117° 12′ CO = 1.222 A HCH = 108° 46′ CH = 1.085 A 2θ = 119° 54′ where 2θ is the angle between the symmetry axes of the methyl groups as determined by analyses of multiplet splittings arising from coupling of internal and over-all rotation. These same analyses yield barriers to internal rotation of 778, 777, and 726 cal/mole for the species (CH3)2CO, (13CH3)2CO, and (CD3)2CO, respectively. Evidence for the general occurrence of “tilted” or “cocked” methyl groups in molecules with methyl groups attached to doubly bonded carbon atoms is presented and discussed.
Gastrointestinal effects of NSAIDs and coxibs.

Nonsteroidal anti-inflammatory drugs (NSAIDs) are among the most commonly used drugs in the world, but their use is limited because of their propensity to cause gastrointestinal (GI) injury. All patients are at risk of GI injury but certain risk factors increase the likelihood of adverse GI effects. The most important include a history of ulcer or GI complications, increasing age, concomitant anticoagulation, concomitant corticosteroid use, and high-dose NSAIDs or multiple NSAIDs (including an NSAID plus low-dose aspirin). Concurrent illness (e.g., severe rheumatoid arthritis, heart disease) has also been reported to increase the risk of GI events. NSAID-associated GI side effects markedly increase health care costs, with up to 31% of cost of managing arthritis patients accounted for through the management of GI side effects. The COX-2 specific inhibitors (coxibs) were developed with the aim of maintaining anti-inflammatory efficacy but improving gastrointestinal safety in comparison to non-selective NSAIDs. The use of COX-2 specific inhibitors significantly decreases the rate of endoscopic ulcers as compared to traditional NSAIDs. Prospective GI outcomes studies also indicate that these agents decrease clinical GI events as compared to non-selective NSAIDs. The number of patients needed to treat to avert one clinical event in one year is approximately 40-100. The cost-effectiveness of coxibs increases (the cost per GI event averted decreases) in patients with high-risk clinical features because they have higher rates of GI hospitalizations and greater use of expensive prophylactic co-therapy.
Effect of pressure on the electrical resistance of EuO

The electrical resistivity of EuO has been measured from room temperature to 70 K and at pressures up to 250 kbar. A semiconductor-to-semiconductor transition is observed around 140 kbar at room temperature, and the conduction remains activated with a narrow gap up to 250 kbar. The magnetic transition temperature is observed to rise rapidly with pressure below 100 kbar but to saturate near 200 K in the 100--250-kbar range.
Potential aerodynamic entrainment of soil from excavation operations in a contaminated area

Abstract Experiments were performed to provide an indication of the amount of material that could be made airborne during soil-working operations in a contaminated area. Contaminated soil was collected, dried, and mixed, and particle size distribution and contamination levels characterized. In a 0.6 × 0.6 m wind tunnel, soil was pumped into an airstream moving at 1.4, 4.6, 6.8, and 8.9 m/s. Airborne mass and particle size samples were collected. The fraction of source soil made airborne increased as a linear function of wind speed. Airborne contamination increased with wind speed at a rate about 4 times the soil mass. Source terms (i.e., fraction of material initially made airborne) can be estimated using the information developed. These can, in turn, be used in diffusion models to estimate downwind contamination levels as required for safety assessments of radioactive or chemical waste sites.
Cultivation of microorganisms in heavy water.

Data are presented on the culture of a variety of algae and other microorganisms in highly deuterated systems. Growth rates for the unicellular green algae Scenedesmus obliquss and Chlorella ralgaris in 99.6% D/sub 2/O were improved so that they approach one-half the rates in H/sub 2/O nutrient media. S. obliquus was also successfully mass cultured in 5-liter units. The blue-green alga Plectonema calothricoides was grown on a continuous laboratory scale in 99.6% D/sub 2/O. A number of other green, blue-green, and red algae and diatoms have been cultured at D/sub 2/O levels from 75 to 99.6%. The bacterium Escherichia coli, the yeast Tonalopsis utilis, and the mold fungus Asperallus niger were grown in fully deuterated media. Protozoa have been cultured at somewhat lower D/sub 2/O concentrationsi Paramecium caudatum routinely in 60% D/ sub 2/O lettuce infusion and Paramecium bursaria in 50% lettuce infusion. In general, algae are best adapted to D/sub 2/O by serial subculyure, 0 to75 to 99 to 99.6% D/sub 2/O, but Chlorella, E. coli, T. utilis, and A. niger can be grown by direct transfer from H/sub 2/O to 99.6% D/sub 2/O nutrient media. (auth)
Receptor-based model accounts for phlebotomy-induced changes in erythropoietin pharmacokinetics.

Abstract Objective Previous clinical studies have demonstrated two distinctive pharmacokinetic behaviors of erythropoietin (EPO): changes in pharmacokinetics (PK) after a period of rhEPO treatment and nonlinear pharmacokinetics. The objective of this work was to study the temporal changes in EPO's PK following phlebotomy in order to propose possible mechanisms for this behavior. Methods Five healthy adult sheep were phlebotomized on two separate occasions 4–6 weeks apart to hemoglobin levels of 3–4 g/dL. PK parameters were estimated from the concentration-time profiles obtained following repeated intravenous bolus PK studies using tracer doses of biologically active 125 I-rhEPO. Based on the changes in clearances, a PK model was derived to provide a mechanistic receptor-based description of the observed phenomena. Results Phlebotomy resulted in a rapid increase in the EPO plasma concentration, which peaked at 760 ± 430 mU/mL (mean ± SD) at 1.8 ± 0.65 days, and which coincided with a transient reduction in EPO clearance from prephlebotomy values, i.e., from 45.6 ± 11.2 mL/hr/kg to 24.3 ± 9.7 mL/hr/kg. As plasma EPO levels returned toward baseline levels in the next few days, a subsequent increase in EPO clearance was noted. EPO clearance peaked at 90.2 ± 26.2 mL/hr/kg at 8.5 ± 3.3 days and returned to baseline by 4–5 weeks postphlebotomy. The proposed model derived from these data includes positive feedback control of the EPO receptor (EPOR) pool. Conclusion The model predicts that: 1) the initial reduction in EPO plasma clearance is due to a transient saturation of EPORs resulting from the phlebotomy-induced high EPO concentration; and 2) the EPOR pool is expandable not only to compensate for EPOR loss but also to adjust to a greater need for EPORs/progenitor cells to restore hemoglobin (Hb) concentration to normal levels.
Exploring the Digital Divide on the U.S.-Mexico Border Through Literacy Narratives

Abstract Building upon the work of Scenters-Zapico's (2010) Generaciones , this article examines the digital literacy development and practices of two students passing through three different educational institutions on the U.S.-Mexico border. The author makes the argument that literacy narratives such as the ones shared here are vital for complementing the work done by broader quantitative studies on the digital divide, as they document differences that may be otherwise overlooked. In exploring the very different narratives of two students transitioning through high school and into a two-year college or four-year university, this article complicates understandings of the digital divide by exploring technological divides between educational institutions and the role that gateways, external sponsors, and self-sponsorship play in students’ technological literacy development, especially when confronted with limitations on access. The discussion and findings have implications for writing program administrators as well as composition teachers and researchers, including those teaching in online environments.
Clusters of DNA damage induced by ionizing radiation: formation of short DNA fragments. II. Experimental detection

The basic 30-nm chromatin fiber in the mammalian cell consists of an unknown (possibly helical) arrangement of nucleosomes, with about 1.2 kb of DNA per 10-nm length of fiber. Track-structure considerations suggest that interactions of single delta rays or high-LET particles with the chromatin fiber might result in the formation of multiple lesions spread over a few kilobases of DNA (see the accompanying paper: W.R. Holley and A. Chatterjee, Radiat. Res. 145, 188-199, 1996). In particular, multiple DNA double-strand breaks and single-strand breaks may form. To test this experimentally, primary human fibroblasts were labeled with [3H]thymidine and exposed at 0 degrees C to X rays or accelerated nitrogen or iron ions in the LET range of 97-440 keV/microns. DNA was isolated inside agarose plugs and subjected to agarose gel electrophoresis under conditions that allowed good separation of 0.1-2 kb size DNA. The bulk of DNA remained in the well or migrated only a small distance into the gel. It was found that DNA fragments in the expected size range were formed linearly with dose with an efficiency that increased with LET. A comparison of the yield of such fragments with the yield of total DNA double-strand breaks suggests that for the high-LET ions a substantial proportion (20-90%) of DNA double-strand breaks are accompanied within 0.1-2 kb by at least one additional DNA double-strand break. It is shown that these results are in good agreement with theoretical calculations based on treating the 30-nm chromatin fiber as the target for ionizing particles. Theoretical considerations also predict that the clusters will contain numerous single-strand breaks and base damages. It is proposed that such clusters be designated "regionally multiply damaged sites." Postirradiation incubation at 37 degrees C resulted in a decline in the number of short DNA fragments, suggesting a repair activity. The biological significance of regionally multiply damaged sites is presently unknown.
Applying the ideal standards model to unmet expectations and satisfaction in friendship

Abstract The present study applies the ideal standards model (ISM) to explore the role of ideal friendship standards on friendship satisfaction in a specific same-sex friendship and responses to unmet expectations in friendships in general. Participants ( N = 284) completed an online survey wherein they reported their expectations on six dimensions of friendship, their friendship satisfaction for a close same-sex friendship, and their response to unmet standards in friendship. The influence of participants’ self-evaluations and ideal standards on friendship satisfaction was mediated by the discrepancy between participants’ close friend and participants’ ideal standards. The flexibility of standards failed to explain variance in satisfaction and higher ideal standards were negatively associated with satisfaction. However, the flexibility of standards was negatively associated with direct communication, avoidance, and revenge in response to unmet expectations in friendships, and positively related to loyalty and acceptance. The present investigation clarifies how friendship ideals influence the evaluation of friendship and responses to unmet expectations.
Comment on "Hidden slow dynamics in water".

A Comment on the Letter by Hel\'en Jansson, Rikard Bergman, and Jan Swenson, Phys. Rev. Lett. 104, 017802 (2010). The authors of the Letter offer a Reply.
Significant Race Differences in Factors Related to the Detention Recidivism of Youthful Offenders

A significant number of youthful offenders in the United States are held in juvenile court detention centers. Of broad concern is the disproportionate impact these placements have on minority youth, with African American and Hispanic youth much more frequently detained in these facilities compared to Caucasian youth. This U.S. study of a 2-county youthful offender population in the Midwest (1 urban, 1 rural) investigated racial differences in both extralegal (demographic, educational, mental health, and history of abuse or neglect) and court-related legal variables that predict detention placement upon recidivism—in other words, a second detention placement. Findings from logistic regression analysis indicated that only a few legal factors (violation of a court order, number of court offenses) predicted for both minority and Caucasian youth, but numerous racially disparate extralegal factors also predicted detention placement upon recidivism. Specifically, unique predictors for minority youth included a h...
"Occasionality" as a Constituent Feature of the Known-in-Common Character of Topics

In an investigation (Adato, 1971) into the ways in which topics get started in ordinary conversation between coworkers in the company cafeteria of a large business firm, I observed that conversants, quite regularly, make use of the occasion of conversation in generating topics. The majority of topics, in the seven lengthy conversations that I examined, arose out of occasioned events such as the tie that one was wearing, the soup that one was eating, the newspaper that was lying on the table or being read, or the remarks that had just been made and which were of no relevance to the topics that they nevertheless were turned into. The following two cases are typical examples:
Dividend capture in NASDAQ stocks

Abstract We examine the importance of dividend-capture trading in NASDAQ stocks by testing for cross-sectional relations between ex-day abnormal returns and bid-ask spreads. Throughout, we find that ex-day returns and spreads are positively related. The relation increases across dividend-yield quintiles and is strongest in high-yield stocks. The relation does not appear in a sample of non-ex-dividend days. These findings indicate that dividend-capture trading affects the ex-day returns of at least some, particularly high-yield, NASDAQ stocks, and that dividend-capture trading is important for understanding ex-dividend-day returns.
Information Literacy Opportunities within the Discovery Tool Environment

Discovery tools such as Primo, EBSCO Discovery Service, Summon, and WorldCat Local aim to make scholarly research more intuitive for students in part because of their single interface for searching across multiple platforms, including the library, fee-based databases, and unique digital collections. Discovery tools are in sync with the way many undergraduates look for information because they offer a more “Google-like” experience in contrast with previous methods of research that required first knowing which database to use, then searching each one differently according to its specifications. However, broad searches across multiple formats with different systems of controlled vocabulary force instructors to rethink the way they teach students to find information. This article will establish best practices to assist librarians in developing instructional classes for students to conduct research using a discovery tool.
In vitro penetration of tritium-labelled water (THO) and [3H]PbTx-3 (a red tide toxin) through monkey buccal mucosa and skin.

Abstract The permeability coefficients ( K p ) for tritium-labelled water (THO) were determined in human and monkey skin, and monkey buccal mucosa. K p of human skin (0.47 × 10 −3 cm/h) correlated favorably with previous reports. K p of hydrated monkey skin for THO (0.77 × 10 −3 cm/h) was not significantly different (P > 0.05) from K p of hydrated human skin (0.88 × 10 −3 cm/h). K p of monkey buccal mucosa for THO (6.15 × 10 −3 cm/h) was significantly greater than that for monkey skin. Penetration and disposition of [ 3 H]PbTx-3 into layers of monkey buccal mucosa and skin was determined. [ 3 H]PbTx-3 (5–7 μCi) dissolved in 2 ml of water was applied to epithelial/epidermal surface (2.8 cm 2 ) at zero time. The relative percent dose recovered from the upper layers of buccal mucosa (epithelium) and skin (epidermis) varied, but at each time interval was less than 2.5% of the dose. At most of the time intervals (2–24h), a larger percent of the dose was recovered from the inner layer of the buccal mucosa (lamina propria) than from the inner layer of skin (dermis). After 24 h, as much as 34 or 13% of the dose was recovered from lamina propria or dermis, respectively. At each time interval studied, less than 2% of dose of [ 3 H]PbTx-3 penetrated into the receptor fluid which bathed the inner surfaces of the lamina propria or dermis. The results of this study demonstrate that monkey buccal mucosa is more permeable than skin to THO and PbTx-3
Chemically Selective Coated Quartz Crystal Microbalance (QCM) Array for Detection of Volatile Organic Chemicals

Liquid flow cells have been fabricated to prepare an array of QCMS operating simultaneously for detection and identification of VOCS in water. TWO signals, a tlequency response and a damping voltage response, were obtained per resonator. A blank QCM was used as a reference to account for changes in liquid density and viscosity. Nine different polymer coatings applied using a spin coat technique have been examined for VOC response under liquid flow conditions. A matrix of three classes of VOCS were examined for each coating with four chemicals in each class. The three classes of VOCS are polar, nonpolar and chlorinated. A pattern recognition technique, called visually empirical region of influence (VERI), was used to cluster the responses in n-dimensional space. Chemicals within a class varying by only one methyl group (e.g., toluene and xylene) are easily discriminated using only two different coatings with three different QCM responses. All chemicak were easily separated and detected with a total of 5 films and 6 responses with >99% accuracy.
The Role of Visualization in Computer Science Education

Computer science core instruction attempts to provide a detailed understanding of dynamic processes such as the working of an algorithmortheflowofinformationbetweencomputingentities.Such dynamic processes are not well explained by static media such as text and images, and are difficult to convey in lecture. The authors survey the history of visualization in computer science education, focusing on artifacts that have a documented positive educational assessment. Changes in how computing technology has affected the developmentand uptakeof such visualization artifactsin computer science education, and how recent technology changes are leading to progress in developing online hypertextbooks are then discussed.
Framing and reframing the environmental risks and economic benefits of ethanol production in Iowa.

Recent research exposing environmental and social externalities of biofuels has undermined the earlier national consensus that they would provide climate mitigation and rural development benefits, but support for ethanol remains strong in Iowa. The objective of this paper is to understand how stakeholder groups in Iowa have framed the benefits and risks associated with ethanol’s impact on the local economy and environment. Our case study draws on in-depth, semi-structured interviews conducted with key informants from agricultural organizations, environmental organizations, and government departments in the state. We find that in Iowa, widespread support for ethanol production exists among government, energy, and farm groups, and that they frame ethanol production as economically beneficial to rural communities and agriculture, while minimizing the possibility of associated environmental risks. Although participants from environmental organizations in Iowa express apprehension about the environmental impacts of expanded corn ethanol production, their unease is muted in relation to economic benefits and in relation to other environmental issues, and few have publicly voiced their concerns. To understand these findings, we draw from the environmental sociology literature that examines the role of powerful natural resource interests in framing the importance of resource extraction and commodity production to community identity and economy and in delegitimizing and naturalizing associated environmental issues and problems. We argue that powerful natural resource interests in Iowa both naturalize environmental problems related to ethanol production and engage in diversionary reframing to emphasize the economic benefits while minimizing or rejecting the potential environmental risks.
Medical student career survey--vascular surgery awareness initiative.

Background The objectives of this survey were to identify medical students’ general knowledge of vascular surgery as a career choice on entrance to medical school, and how student perspectives change during their exposure to clinical disciplines. Furthermore, we sought to determine which factors may influence the choice of a particular career path, and to apply this knowledge to improve the recruitment process of medical students into the specialty of vascular surgery. Methods A one-time anonymous questionnaire consisting of 21 open and multiple-choice questions was distributed to first- (MS1), second- (MS2), and third-year (MS3) medical students at a large single-campus medical school. Responses were collected and subjected to analysis. Results Three hundred thirty-eight medical students responded to the survey (110 MS1, 126 MS2, and 102 MS3). Two hundred thirty-six MS1 and MS2 students had no clinical exposure to vascular surgery. Of 102 MS3 students having completed a general surgery rotation, 38 had exposure to vascular surgery. Of MS1 and MS2 students, 49% would consider vascular surgery. An additional 19% were willing to consider vascular surgery if the length of training was reduced. Twenty-six percent of the clinical students rotated on a vascular surgery service during their clinical general surgery rotation, of which 78% reported a positive experience. Only 26% (10 of 38) still considered vascular surgery as a career at the MS3 level. Thirty-four percent of students would consider vascular surgery if the training was reduced from 7 to 5 years. However, only 5% of MS1 and MS2 (11 of 236) and 9% of MS3 (9 of 102) students were aware of the 0 + 5 training program. As students advanced in medical school, lifestyle (31% MS1 vs. 63% MS3, P P Conclusions Medical students have minimal knowledge of vascular surgery on entry to medical school; however, many are willing to consider vascular surgery as a career. Lack of exposure in the first 2 years of medical school and lifestyle considerations may be deterrents for students to choosing vascular surgery as a career. To improve the recruitment process, focused education and interaction with preclinical medical students are needed.
Prednisone inhibits formation of cortical bone in sham-operated and ovariectomized female rats.

Prednisone inhibits bone formation and causes bone loss. To investigate possible mechanisms and sites, the effects of sham operation, ovariectomy, and prednisone were determined on bone and mineral metabolism in 7-week-old growing female rats. Forty animals were divided into groups of 10 each. Sham operation and ovariectomy were performed. One week later, pellets containing 5 mg prednisone or drug free were implanted S.C. at the back of the neck. Four weeks later, animals were sacrificed and tibiae were removed for histomorphometric analysis of the middiaphysis and proximal metaphysis. In both sham-operated and ovariectomized rats, prednisone (1) reduced weight gain (P<0.02) and did not alter uterine weight; (2) lowered serum magnesium (Mg) (P<0.001) and did not change serum calcium (Ca), phosphate (P), 25-hydroxyvitamin D (25OHD), or 1,25-dihydroxyvitamin D [1,25(OH)2D]; (3) produced striking increases in calcified cartilage, reduced cross-sectional area (P<0.05) and cortical area (P<0.01) and did not change medullary area of the tibial diaphysis; (4) lowered periosteal and endocortical bone formation and apposition rates; and (5) increased mean cancellous bone area (P<0.05) and cancellous bone perimeter (P<0.01) of the tibial metaphysis. In both control and prednisone-treated rats, ovariectomy (1) reduced uterine weight (P<0.001); (2) did not change serum Ca, P, Mg, 25OHD, or 1,25(OH)2D; (3) did not change mean cross-sectional, medullary, or cortical areas; (4) increased periosteal bone formation and apposition rates (P<0.01) and did not alter endosteal bone formation and apposition rates, and (5) decreased cancellous bone area (P<0.01) and cancellous bone perimeter (P<0.01). Thus, in short-term studies, prednisone increased calcified cartilage and inhibited the formation of cortical bone at periosteal and endosteal surfaces and reduced cortical bone of the tibia in both sham-operated and ovariectomized, rapidly growing animals.