cssi/SciSciGPT-SciSciNet huggingface dataset:
Mechanical modulation of nascent stem cell lineage commitment in tissue engineering scaffolds

Abstract Taking inspiration from tissue morphogenesis in utero, this study tests the concept of using tissue engineering scaffolds as delivery devices to modulate emergent structure–function relationships at early stages of tissue genesis. We report on the use of a combined computational fluid dynamics (CFD) modeling, advanced manufacturing methods, and experimental fluid mechanics (micro-piv and strain mapping) for the prospective design of tissue engineering scaffold geometries that deliver spatially resolved mechanical cues to stem cells seeded within. When subjected to a constant magnitude global flow regime, the local scaffold geometry dictates the magnitudes of mechanical stresses and strains experienced by a given cell, and in a spatially resolved fashion, similar to patterning during morphogenesis. In addition, early markers of mesenchymal stem cell lineage commitment relate significantly to the local mechanical environment of the cell. Finally, by plotting the range of stress–strain states for all data corresponding to nascent cell lineage commitment (95% CI), we begin to “map the mechanome”, defining stress–strain states most conducive to targeted cell fates. In sum, we provide a library of reference mechanical cues that can be delivered to cells seeded on tissue engineering scaffolds to guide target tissue phenotypes in a temporally and spatially resolved manner. Knowledge of these effects allows for prospective scaffold design optimization using virtual models prior to prototyping and clinical implementation. Finally, this approach enables the development of next generation scaffolds cum delivery devices for genesis of complex tissues with heterogenous properties, e.g. , organs, joints or interface tissues such as growth plates.
Better statistics for better decisions: Rejecting null hypotheses statistical tests in favor of replication statistics

Statistics can address three different types of questions (Royall, 1997): What should I believe? How should I evaluate this evidence? What should I do? The first two are of great importance to scientists: Finding the answers to these questions defines their praxis. The last question, on which we focus here, is of greater relevance to practitioners who must deal with decisions that have practical consequences. In its simplest form, a decision is a choice between two alternative courses of action. All other things being equal, optimal decisions favor courses of action that are expected to yield higher returns (e.g., better indices of class attendance) and are less costly to implement over those that are expected to yield lower returns and cost more. Choices with dominant alternatives are trivial; it is when costs and expected returns covary in the same direction that practical choices may become dilemmas, invoking the aid of decision committees and statisticians. Costly actions must be justified by their returns exceeding some minimum standard of expected improvement. Once that minimum improvement is defined, researchers produce data from which statisticians, in turn, are expected to determine whether the minimum improvement is real or not. Null hypothesis significance tests (NHST) are the conventional tool for making these evaluations. The privileged status of NHST is most clearly reflected in its prevalence as a diagnostic tool in the psychological and educational literature and in its entrenchment in the statistical training of education and psychology professionals. We will illustrate its use by applying the NHST routine to the solution of a practical binary-choice situation and demonstrate its inadequacy in informing a decision in that scenario. We argue that the probability of obtaining a minimum cost-effective return is more informative than arbitrary decisions about statistical significance and provide the rationale and algorithm for its estimation.
Failures to Compute

Slayton draws on historical documents and interviews to compare how physicists and computer scientists evaluated missile defense systems.
Humoral and cellular immunities elicited by DNA vaccines: Application to the human immunodeficiency virus and influenza

Abstract Vaccines comprised of plasmid DNA constructs providing expression of cDNA-encoded antigens elicit potent humoral and cellular immunities in animals including major histocompatibility complex (MHC) I-restricted cytotoxic T lymphocyte (CTL) responses. This approach has been exemplified by experiments demonstrating protection of mice and ferrets from influenza infection: DNA vaccines encoding the influenza nucleoprotein (NP) gene protected against cross-strain challenge by cellular immunities while vaccines encoding hemagglutinin (HA) provided antibody-mediated protection to homologous virus. DNA vaccines, expressing either HIV-1 gp120 or rev, were also used to vaccinate mice and nonhuman primates. Both CTL and type 1-like T lymphocyte (Th1) immunities as well as gp120-specific antibodies were elicited by DNA vaccination. The ability of DNA vaccines to readily elicit both CTLs and antibodies distinguish them from conventional vaccines comprised of killed virus or purified antigen and make them an attractive vaccine approach to test with many microbial pathogens.
Link colors guide a search

While much basic research exists on the effects of various visual properties on visual search, the application of such research to real-world tasks is lacking. The purpose of this research is to address the lack of empirical validation for design guidelines that affect visual search. One common design element used in Web interface design is link color. The general research question asked is how text color affects visual search. This research demonstrates, with reaction time and eye movement analysis, the dramatic but imperfect control a designer has on guiding the attention of users with text color. Experimental support for the differentiation of visited link colors is presented, along with analyses of the advantages provided by differentiating link colors.
Thin metal films as applied to Schottky solar cells: optical studies.

Thin metal films (≈100 A) have been studied for application to Schottky barrier solar cells (SBSC). Metal films having >55% transmission over the solar spectrum and resistance of 20 Ω/□ have been applied to Si to form a rectifying contact. A 9.5% sunlight efficient SBSC was produced using 50-A Cr adjacent to the Si for good adhesion and high open circuit voltage and a 50-A Cu overlayer to produce low sheet resistance. Film quality has been related to evaporation rate, metal layer selection, and substrate conditions. Solar cell performance is determined by the transmission and resistance of the thin metal films. Spectral response data show the SBSC to exhibit improved short wavelength sensitivity compared to the p-n Si solar cell.
Pellicle complex ofEuglena gracilis: Characterization by disruptive treatments

Euglena gracilis was treated with 4% colchicine, 0.5% β-mercaptoethanol, 0.5% Triton X-100, and 8% tannic acid in attempting to characterize its pellicle complex. Colchicine had no visible effects on the microtubules of the pellicle, canal or reservoir. Colchicine in dimethyl sulfoxide disorganized the reservoir region. Colchicine was shown to enter the cell by its ability to inhibit flagellar regeneration. Mercaptoethanol destroyed most of the organelles in the cell. Only the tripartite plasmalemma of the pellicle complex remained normal. The microtubules of the cell and the protein layer underlying the plasmalemma were disrupted by mercaptoethanol treatment. Triton X-100 caused membranes of internal organelles to round, up become distended and swollen, but had no morphological effect on the plasmalemma. The ridge-groove shape of the pellicle remained intact after every treatment. Mercaptoethanol caused an indentation of the ridges over the position of a disrupted microtubule, suggesting a supporting function of the microtubules. Distension of endoplasmic reticulum by Triton X-100 revealed more clearly its association with the pellicle complex. The ability of the pellicle ofEuglena gracilis to maintain its integrity under a number of disruptive treatments was demonstrated.
Pigment systems and electron transport in chloroplasts. II. Emerson enhancement in broken spinach chloroplasts.

Abstract The Emerson enhancement effect using red illumination supplemented by far-red light is a characteristic phenomenon of photosynthetic oxygen evolution by plants and algae. It has been cited as an important evidence in support of the mechanism of photosynthetic electron transport involving two light reactions operating in series. The present study confirms the occurrence of enhancement in isolated, broken spinach chloroplasts for the photoreduction of NADP + by water: [H 2 O → NADP + ] reaction. Far-red light at 700 nm is supplemented optimally with wavelengths of 650 or 670 nm. Divalent cations such as magnesium or manganese are shown to be required for enhancement to occur. The optimum concentrations of added MgCl 2 or MnCl 2 are about 7.5 mM; at concentrations below 3 mM enhancement is not obtained. The critical dependence on divalent ion concentration is felt to be the reason why the enhancement phenomenon has not been observed in some previous studies using broken chloroplasts. A role for Mg 2+ is proposed in which it alters the structure of the active chloroplast membranes in a manner which controls the transfer of electronic excitation between the two photosynthetic pigment systems. These findings favor the series two-light reaction mechanism over the alternative parallel scheme.
Scanning electron microscopy of chicken lymphocytes: a comparative study of thymic, bursal, and splenic lymphocytes.

Abstract Using scanning electron microscopy (SEM), human and murine lymphocytes have been divided into 2 morphological cell populations based on their surface morphology (i.e. T cells are smooth and B cells were rough). This classification system is, however, controversial, and not all investigators feel this is a valid criteria for delineating T and B cells. The chicken provides an ideal system to study this problem with its compartmentalization of T and B cells in the thymus and bursa of Fabricius, respectively. The splenic, bursal, and thymic lymphocytes of 2–9 week old chickens were examined by SEM and scored as either rough (villous), intermediate, or smooth based on the number of surface projections present. We observed the smooth type to be most prominent regardless of the source of the cell ( > 90%), even in the spleen which showed the greatest diversity. SEM, therefore, cannot be used as a tool to distinguish between T and B cell populations in the chicken.
Comparison of two methods of using liquid swine manure as an organic fertilizer in the production of filter-feeding fish

Abstract Yield trial experiments were conducted in 10.5 m 2 plastic-lined pools to test liquid swine manure as an organic fertilizer for fish production. Silver carp ( Hypophthalmichthys molitrix ), bighead carp ( Aristichthys nobilis ), and tilapia ( Tilapia nilotica ) were cultured together for 52 days during August and September 1977 to determine growth and yield responses to various manure fertilization treatments. Net fish yields were 1.8 times greater in pools receiving direct manure fertilization than in pools receiving phytoplankton slurries produced with comparable amounts of manure. Early morning dissolved oxygen concentrations became critical ( −1 day −1 .
Entrapment of proteins in glycogen-capped and hydrazide-activated supports

A method is described for the entrapment of proteins in hydrazide-activated supports using oxidized glycogen as a capping agent. This approach is demonstrated using human serum albumin (HSA) as a model binding agent. After optimization of this method, a protein content of 43 (±1) mg of HSA/g support was obtained for porous silica. The entrapped HSA supports could retain a low-mass drug (S-warfarin) and had activities and equilibrium constants comparable to those for soluble HSA. It was also found that this approach could be used with other proteins and binding agents that had masses between 5.8 and 150 kDa.
Analysis of the expression and immunostimulatory capacity of class I major histocompatibility antigens on rat trophoblast cell lines.

In rat strains expressing the a and other major histocompatibility complex (MHC) haplotypes, subpopulations of placental trophoblast cells synthesize the nonclassical class I Pa antigen in preference to the classical RT1.Aa antigen. In this study, a rat trophoblast cell line, R8RP.3, which was derived from midgestation placentas of PVG.R8 (RT1.Aa) rats, was shown to express class I antigens similarly to those of trophoblast cells in situ. Both unstimulated and IFN-gamma-exposed metabolically labeled R8RP.3 cells synthesized more Pa than RT1.Aa antigen. The reverse was true for labeled spleen cells from PVG.R8 rats. The R8RP.3 cells failed to stimulate allogeneic lymphocyte proliferation even when high levels of both classical and nonclassical class I MHC antigens were expressed on their membranes after incubation with IFN-gamma. These experiments thus supply the first evidence that the inductive phase of the immune response is not promoted by trophoblast cell class I MHC antigens, which could explain the failure of mothers to mount immune responses to class I MHC positive trophoblast cells.
Lack of expression of serotonin receptor subtype -1a, 1c, and -2 mRNAs in gonadotropin-releasing hormone producing neurons of the rat

Serotonin is one of the neurotransmitters which participates in the regulation of gonadotropin-releasing hormone (GnRH) release from the hypothalamus. In order to test the hypothesis that serotonin acts directly on the GnRH neurons, dual in situ hybridization with 35S-labeled cRNA probes encoding for the serotonin receptor subtypes-1a, -1c, or -2 together with digoxigenin-labeled GnRH cRNA probes was applied to histological sections of the septum-diagonal band and preoptic area. The results of these studies show that many neurons in these brain regions contain the various serotonin receptor mRNAs, however, no cells were detected that contain both GnRH mRNA and serotonin receptor mRNAs. It is therefore suggested that the effects of serotonin on GnRH release are not mediated by direct actions of the neurotransmitter through serotonin-1a, -1c or -2 receptors on GnRH neurons but instead through other, yet unidentified serotonin receptor subtypes or through non-serotoninergic intermediary neurons.
Maintenance of supersaturation II: indomethacin crystal growth kinetics versus degree of supersaturation.

ABSTRACT: This study compares the kinetics of crystal growth of indomethacin from supersaturated suspensions at varying degrees of supersaturation (2 ≤ S ≥ 9) in the presence of seed crystals of the γ-form of indomethacin, the lowest energy polymorph. At high S (6 ≤ S ≥ 9), the crystal growth was first order with rate coefficients ( k G ) that were nearly constant and consistent with the value predicted for bulk-diffusion control. At lower S ( k G values were significantly smaller, decreasing approximately linearly with a decrease in S . The decline in k G at low S was attributed to a prolonged period during the initial stages of crystal growth in which surface integration was rate limiting. The apparent solubility of indomethacin after crystal growth for 3 days increased by ∼1.6-fold at both low ( S = 2) and high ( S = 6) degrees of supersaturation suggesting that a higher energy surface layer was deposited on the γ-form seed crystals during crystal growth. When growth experiments were repeated at low S in the presence of indomethacin seed crystals isolated from a previous crystal growth experiment (i.e., seed crystals having higher energy surface), k G matched the higher values observed for bulk diffusion-controlled crystal growth. Crystal growth experiments were also conducted at S k G under conditions where deposition of a higher energy surface could not occur. At these conditions, the smaller value of k G indicative of surface integration control was again observed and the apparent solubility of indomethacin after crystal growth matched that of the γ-form. A quantitative mechanistic understanding of the crystal growth kinetics of indomethacin derived from experiments at high and low S may be useful in future studies aimed at understanding the inhibitory effects of pharmaceutical excipients on the crystal growth of poorly soluble compounds and their utility in maintaining drug supersaturation during oral absorption.
An Exploratory Model of Interpersonal Cohesiveness in New Product Development Teams

There has been a heavy emphasis in new product development (NPD) research on intrateam issues such as communication, trust, and conflict management. Interpersonal cohesiveness, however, has received scant attention. In addition, there are conflicting findings regarding the effects of close-knit teams, which seem to have a beneficial effect up to a point, after which the tight bond becomes a detriment. This paper addresses these issues by introducing an exploratory model of interpersonal cohesiveness→NPD performance that includes antecedents, consequences, and moderating factors. Antecedents of interpersonal cohesiveness include clan culture, formalization, integration, and political dominance of one department, while consequences are groupthink, superordinate identity, and, ultimately, external/internal new product (NP) performance. The relationships among interpersonal cohesiveness, groupthink, and superordinate identity appear to be influenced by two moderating factors: team norms and goal support. Additionally, product type is identified as a moderator on the effects of both groupthink and superordinate identity on external NP performance. The model is built from two sources: a synthesis of the literature in small group dynamics and NPD, and qualitative research conducted across 12 NPD teams. Individual team leaders were interviewed first, followed by interviews with two additional members on each team, for a total of 36 interviews. In keeping with the goals of qualitative research, the interviews and analysis were used to identify and define aspects of interpersonal cohesiveness rather than to test a preconceived model. Representation of different industries and product types was sought intentionally, and variance in NP innovativeness as well as in NP market success/profitability became key criteria in sample selection. The exploratory model and propositions developed in this study provide a framework for understanding the role of interpersonal cohesiveness in NPD teams and its direct and indirect effects on NP performance. Although a significant amount of research on cohesiveness has been conducted in previous studies of small groups, the narrow laboratory settings of that research have limited the generalizability of the findings. This study therefore serves as a useful starting point for future theory development involving interpersonal cohesiveness in NPD. It also provides a guide for managers in dealing with team cohesiveness.
STRUCTURAL CHARACTERIZATION OF AROMATIC-AROMATIC COMPLEXES BY ROTATIONAL COHERENCE SPECTROSCOPY

Rotational coherence spectroscopy (RCS) has been applied in structural studies of (a) aromatic−aromatic van der Waals complexes of the form M−X, where M = perylene or fluorene and X = benzene or toluene, and (b) aromatic−aliphatic hydrocarbon dimers of the form M−Y, where M is as above and Y = cyclohexane or methylcyclohexane. For all of the perylene complexes the experimentally determined rotational constants are found to be consistent with centrally bound, parallel-stacked structures in which the monomer planes are separated by a distance of 3.5−4.3 A. Analogous geometries also characterize the fluorene−aliphatic species. However, the two fluorene−aromatic complexes have structures that depart from the parallel-stacked form. Both species have slipped geometries in which the monomer planes are not directly over one another. And, in the case of fluorene−benzene, the two aromatic planes are tilted with respect to one another. These differences are attributed to the significant contribution of electrostatic...
Oblique Wing Aerodynamics

Abstract : The aerodynamic performance of a wing at an oblique deployment orientation has been found through wind tunnel testing to affect both the lateral and longitudinal stability of a cruise missile. While conventional analysis tools are insufficient for calculating the aerodynamics of an oblique wing, a suitable method has been determined for use with the USAF Missile DATCOM code. Comparisons made between wind tunnel results and Missile DATCOM calculations show that Missile DATCOM can produce a reasonable approximation of the aerodynamics of a wing at oblique deployment angles.
Identification and location of the histone H2A and H3 genes by sequence analysis of sea urchin (S. purpuratus) DNA cloned in E. coli

A 2000 base pair (bp) DNA fragment can be excised from sea urchin (S. purpuratus) histone gene repeat units with restriction endonuclease Eco R1. This DNA, which has been cloned in a bacterial plasmid, is known to encompass two of the five histone genes. The fragment has a single endonuclease Hind III cleavage site in one of the genes and a Hae III cleavage site in the other gene. We now report the nucleotide sequences of 62 bp adjacent to the Hind III site and 42 bp adjacent to the Hae III cleavage site. The results identify the cloned DNA as histone genes, show that it codes for histone proteins H2A and H3, and locate and orient H2A and H3 genes with respect to restriction endonuclease sites in the repeat unit.
RESPONSES OF ENGELMANN SPRUCE FORESTS TO NITROGEN FERTILIZATION IN THE COLORADO ROCKY MOUNTAINS

Two old-growth coniferous forests in Colorado with differing initial soil conditions responded differently to four years of low-level fertilization with ammonium nitrate. The site (Fraser) with an average initial organic horizon soil C:N ratio of 36 and nitrogen (N) pool of 605 kg/ha showed no significant increase in net N mineralization rates. At the Fraser site, foliar and organic horizon soil percentage N increased significantly. In contrast, N mineralization rates and inorganic soil N increased significantly at the site (Loch Vale) with greater soil N (C:N of 24, N pool of 991 kg/ha), while foliar N and soil percentage N in the organic layer did not change. We predict continued fertilization at Fraser will narrow the soil C:N ratio to a point where increases in biogeochemical N cycling and fluxes will be detected. Additional N inputs to the site with already low soil C:N ratios will enhance N mineralization rates and leaching losses. The coniferous forests at Fraser and Loch Vale are similar in species composition, stand age, substrate, aspect, and climate. The differences in soil conditions strong enough to cause contrasting responses to fertilization could be due to differences in atmospheric N deposition. Regardless of the reason, the size of the organic soil N pool and C:N ratio of mature coniferous forests in Colorado controls the responsiveness of N pools and fluxes to fertilization, and even low levels of fertilization are sufficient to initiate measurable biogeochemical changes. Corresponding Editor: W. L. Silver
Bayesian Estimates for Vector Autoregressive Models

This article examines frequentist risks of Bayesian estimates of vector autoregressive (VAR) regression coefficient and error covariance matrices under competing loss functions, under various noninformative priors, and in the normal and Student-t models. Simulation results show that for the regression coefficient matrix, an asymmetric LINEX estimator does better overall than the posterior mean. No dominating estimator emerges for the error covariance matrix. We find that the choice of prior has a more significant effect on the estimates than the form of estimator. For the VAR regression coefficients, a shrinkage prior dominates a constant prior. For the error covariance matrix, Yang and Berger's reference prior dominates the Jeffreys prior. Estimation of a VAR using U.S. macroeconomic data yields significantly different estimates under competing priors.
Statistical model of inclusive distributions: Formulation of the model and mean-field approximation

We formulate a statistical model of inclusive distributions. The source function of the observed particle is regarded as a random variable on phase space; its distribution is determined by a Lorentz-invariant probability density. We suggest that the Lorentz invariance of the correlation functions is broken spontaneously; this may account for the observed anisotropy of the inclusive distributions.
Effect of surface adsorption and agglomeration on the packing of particles

Abstract In previous parts of this series, the dependence of the maximum volume fraction of spherical particles, o max , of a slurry was related to absorption and immobilization of the liquid by the suspended particles. In this report, the dependence of o max on simultaneous surface absorption and particle agglomeration is discussed.
Standardizing methylation method during phospholipid fatty acid analysis to profile soil microbial communities

Phospholipid fatty acid (PLFA) as biomarkers, is widely used to profile microbial communities in environmental samples. However, PLFA extraction and derivatization protocols are not standardized and have widely varied among published studies. Specifically investigators have used either HCl/MeOH or KOH/MeOH or both for the methylation step of PLFA analysis, without justification or research to support either one. It seems likely that each method could have very different outcomes and conclusions for PLFA based studies. Therefore, the objective of this study was to determine the effect of catalyst type for methylation on detecting PLFAs and implications for interpreting microbial profiling in soil. Fatty acid samples extracted from soils obtained from a wetland, an intermittently flooded site, and an adjacent upland site were subjected to HCl/MeOH or KOH/MeOH catalyzed methylation procedures during PLFA analyses. The methylation method using HCl/MeOH resulted in significantly higher concentrations of most PLFAs than the KOH/MeOH method. Another important outcome was that fatty acids with a methyl group (18:1ω,7c 11Me, TBSA 10Me 18:0, 10Me 18:0, 17:0 10Me and 16:0 10Me being an actinomycetes biomarker) could not be detected by HCl/MeOH catalyzed methylation but were found in appreciable concentrations with KOH/MeOH method. From our results, because the HCl/MeOH method did not detect the fatty acids containing methyl groups that could strongly influence the microbial community profile, we recommend that the KOH/MeOH catalyzed transesterification method should become the standard procedure for PLFA profiling of soil microbial communities.
Potency and selectivity of P2/P3-modified inhibitors of cysteine proteases from trypanosomes

A systematic study of P2 and P3 substitution in a series of vinyl sulfone cysteine protease inhibitors is described. The introduction of a methyl substituent in the P2 phenylalanine aryl ring had a favorable effect on protease inhibition and conferred modest selectivity for rhodesain over cruzain. Rhodesain selectivity could be enhanced further by combining these P2 modifications with certain P3 amide substituents.
Prospective associations among family form, family processes, and adolescents' alcohol and drug use

The present study was designed to disentangle and define the unique contributions of family form and family processes to substance use and association with deviant peers among adolescents. Eighty adolescents and their mothers participated in the study; half were from divorced single-parent families and half were from families in which the parents were still married. Maternal assessments of interparental conflict and the quality of the mother-adolescent relationship were used to prospectively forecast adolescent reports of substance use and affiliation with deviant peers one year later. The results revealed that mother-adolescent conflict predicted adolescent alcohol use, and maternal acceptance-rejection predicted both drug use and affiliation with deviant peers. These findings support the hypothesis that family processes rather than family form forecast adolescents' substance use and deviant peer affiliation. Clinical implications of the findings are discussed.
Historical view of the workweek

The recent movement toward workweek schedules and changes in the workweek, such as the four-day, 40-hour week and flexitime, is part of a long historical pattern affecting the length and pattern of the workweek. As will be pointed out, this recent movement is a continuation of earlier trends, but it also represents a shift in emphasis. The purpose of this paper is to present a brief overview of this historical movement, and to place recent workweek developments into a historical perspective and examine their dimensions.
Activation of duration-sensitive auditory cortical fields in humans

The influence of stimulus duration on auditory evoked potentials (AEPs) was examined for tones varying randomly in duration, location, and frequency in an auditory selective attention task. Stimulus duration effects were isolated as duration difference waves by subtracting AEPs to short duration tones from AEPs to longer duration tones of identical location, frequency and rise time. This analysis revealed that AEP components generally increased in amplitude and decreased in latency with increments in signal duration, with evidence of longer temporal integration times for lower frequency tones. Different temporal integration functions were seen for different N1 subcomponents. The results suggest that different auditory cortical areas have different temporal integration times, and that these functions vary as a function of tone frequency.
Analysis of childhood pedestrian deaths in New Mexico, 1986-1990

Study objective: To determine if the mechanism of fatal childhood pedestrian injuries correlated with location, injury pattern, and age of the pedestrian and to determine ethnic differences in fatality rates. Design: Retrospective review of state medical investigator reports and autopsies from 1986 to 1990. Logistic regression and χ 2 were used to test for statistically significant differences between the groups in our data set. Type of participants: New Mexican children, 0 to 14 years old fatally injured by moving vehicles. Results: Sixty-four children died for an overall fatality rate of 3.8 (per 100,000). Native American children and children younger than 5 years experienced the highest fatality rates. Children younger than 5 years were more likely to be crushed under the wheels of a slow-moving vehicle in both a nontraffic and a traffic location, whereas older children were found more often to have died from injuries from a high-speed impact event in a traffic location ( P P = .001) and spinal fractures ( P = .02) occurred more frequently in impact than crush injuries. Conclusion: Young children are at risk for a crush injury in both the traffic and nontraffic environment.
Asymmetric Contribution of the Conserved Disulfide Loop to Subunit Oligomerization and Assembly of the Nicotinic Acetylcholine Receptor

The acetylcholine receptor (AChR) at the motor synapse is a pentamer of homologous subunits with the composition α2βγδ. Owing to the circular arrangement of subunits that forms a central ion channel, each subunit interface contains contributions from opposite faces of each subunit, designated + and −. Common to all subunits of the AChR and members of its superfamily is a disulfide loop formed between cysteines 128 and 142 of the major extracellular domain. To gain insight into the structural contribution of the disulfide loop and its possible location, we mutated the invariant proline at position 136 to glycine (P136G) and examined subunit assembly. When introduced into any AChR subunit, P136G disrupted assembly by affecting the − face of the subunit, suggesting equivalent positioning of the loop in each subunit and localization to the − face. Also, the contribution of the loop in the overall assembly process differed for each subunit. In the β and γ subunits, P136G prevented assembly of higher order heteroligomers, whereas in the α and δ subunits, P136G prevented transport of assembled pentamers to the cell surface. The results demonstrate asymmetry in the contribution of the disulfide loop to formation of subunit interfaces, and that the loop in each subunit contributes at different stages of assembly.
Stop-flow study of renal function in conscious water snakes (natrix sipedon)

Abstract 1. 1. Stop-flow evaluation of renal function was carried out in conscious water snakes, Natrix sipedon. 2. 2. Distal inulin urine-to-plasma (U/P) ratio increased while relative sodium U/P ratio (U/PNa/U/PIn) decreased, suggesting distal reabsorption of sodium and water. 3. 3. Increases in relative sodium and potassium U/P ratios occurred in the proximal regions. 4. 4. Decrease in inulin U/P ratio occurred in proximal region, suggesting a net addition of water to the tubular lumen. 5. 5. Relative urate U/P ratio tended to increase in same region as sodium and potassium peaks. Although this increase was not statistically significant, it suggested a possible interaction of sodium, potassium and water movements with urate movement in this region. This possibility in discussed.
Isoflurane and pentobarbital reduce AMPA toxicity in vivo in the rat cerebral cortex.

Background Isoflurane and pentobarbital can reduce alpha-amino-d-hydroxy-5-methyl-4-isoxazole-propionate (AMPA) receptor-mediated toxicity in vitro. However, their effect on AMPA toxicity in vivo is not known. The present study was undertaken to evaluate the effects of isoflurane and pentobarbital on the in vivo neurotoxicity produced by AMPA. Methods Wistar-Kyoto rats were allocated to one of seven groups (n = 8 per group): isoflurane 1 minimum alveolar concentration, isoflurane electroencephalogram burst suppression (EEG-BS), low-dose pentobarbital, pentobarbital EEG-BS, NBQX, conscious, and sham groups. AMPA 30 nm was injected into the cortex. An equivalent volume of cerebrospinal fluid was injected into the cortex in the sham group. In the NBQX group, 200 nm NBQX was injected into the cortex with the AMPA. In the isoflurane and pentobarbital groups, anesthesia was maintained for a period of 5 h. Animals in the conscious, NBQX, and sham groups were allowed to awaken immediately after the AMPA injection. Injury to the cortex was evaluated 48 h later. Results Isoflurane reduced AMPA-induced cortical injury (4.5 +/- 1.9 mm3 and 1.7 +/- 0.8 mm3 in the 1 minimum alveolar concentration and EEG-BS groups, respectively) in comparison to the conscious group (7.2 +/- 0.8 mm3). Pentobarbital reduced cortical injury when administered in EEG-BS doses (2.2 +/- 0.7 mm3) but not when administered in sedative doses (8.6 +/- 0.9 mm3). NBQX reduced AMPA-induced cortical injury (1.2 +/- 0.5 mm3). Conclusions Isoflurane and pentobarbital reduced cortical AMPA excitotoxicity. The magnitude of injury reduction was similar to that produced by NBQX when the anesthetics were administered in EEG-BS doses. These results are consistent with the previously demonstrated ability of isoflurane and pentobarbital to inhibit AMPA receptor responses.
The effect of temperature on soot formation in premixed flames

Abstract Soot production in atmospheric pressure, laminar premixed flames of toluene and decalin was studied by varying the composition of the fuel/O2/N2 mixture. As the O 2 (N 2 + O 2 ) ratio was increased, the onset of sooting occurred at higher fuel O 2 ratios and at higher calculated adiabatic flame temperatures. Temperatures measured using two-wavelength emission pyrometry, however, showed that the flame temperatures at the soot thresholds were constant for each fuel (1750K for toluene and 1720K for decalin). Soot volume fractions were also measured, using a multiwavelength laser extinction technique, as functions of equivalence ratio, O 2 (N 2 + O 2 ) ratio, and experimental flame temperature. The plateau soot volume fractions for each fuel were found, at any given value of the measured flame temperature, to be independent of the fuel O 2 and the O 2 (N 2 + O 2 ) ratios, over the range of variation of these parameters studies; they were dependent only on the flame temperature.
Ideas, Interests, and Institutions: Challenging the Property Rights Paradigm in Botswana

Recent work in international studies and comparative politics scrutinizes the relative importance of ideas, interests, and institutions as sources of policy change. A growing body of scholarship identifies ideas as the main causal factors, influencing perceived interests as well as perceived policy options. Others contend that policies can best be understood as products of institutions. Neither explanation can account for both policy choice by politicians and the implementation strategies of administrators. In Botswana, the use of professional criteria for hiring and advancement encourages adherence to international professional norms within the bureaucracy, but electoral competition gives politicians more reason to be attentive to local political concerns. The institutions that define relations of authority among actors with different motivations shape the outcomes of policy choice and implementation. Institutions influence the attentiveness of policy-makers to ideas when making decisions, the degree of attention particular policy-makers give to ideas from particular sources, and the degree of acceptance that ideas must achieve to affect policy. Better evaluations of political development can be achieved through attentiveness to the mix of actors involved in policy decisions, the diversity of institutions and ideas that affect their policy preferences, and the relations of authority that shape their relative influence over policy choice and implementation.
Interpretation of the moduli of trifunctional model elastomers of polydimethylsiloxane

A survey is made of published experimental values of the elongation moduli of trifunctional model networks of polydimethylsiloxane [Si(CH3)2O]. The results thus obtained are interpreted in light of recent molecular theories of rubberlike elasticity, particularly with regard to predicted values of the modulus, the degree of nonaffineness of the deformation, the relevance of the network sol fraction, and the efficiency and possible importance of the trapping of interchain entanglements. The most important result of this study is the conclusion that it is not necessary to invoke equilibrium contributions from interchain entanglements in order to interpret the experimental results presently available in the literature.
Reforming Urban Education: A Review of Recent Reports and Legislation

Following the National Commission on Excellence Report, “A Nation at Risk’, a number of additional reports were issued calling for major changes in American public education. Because advocates for poor and minority groups saw a class bias in the recommendations of these reports, there quickly followed a subset of reports arguing that the “disadvantaged” should not be overlooked in the education reform movement. Not surprisingly, these reports have received less attention than the “mainstream” ones. This article reviews recent urban education reform reports and legislation, paralleling them to determine whether the reformers have been able to influence policy and whether the reforms they advocate would be likely to benefit the disadvantaged.
Using incomplete moments to measure inequality

Abstract Incomplete moments of the income distribution form natural building blocks for measuring inequality: for example, income quintiles, the Lorenz curve, Pietra and Gini measures of inequality all depend upon the incomplete moments of the income distribution. This paper discusses these relationships and shows that they are easily calculated for a very broad family of distributions because they possess a ‘closure’ property. Empirical illustrations are given for the white family income distribution for the 1948 to 1980 period.
Mechanistic and synthetic aspects of macrolide ring closure

Abstract Kinetic studies have substantiated the idea of a “double-activation” mechanism for macrolide ring closure from relatively electron-rich 2-pyridyl thiolesters while a change of mechanism is observed for electron-poor 2-pyridyl thiolesters. Mechanistic and synthetic aspects of the ion-assisted cyclization are also discussed.
Lead in hair of urban and rural small mammals.

A study of the effect of proximity to roads or the body burden of lead was made with populations of small mammals. Hair samples of sorex sp., Peromyscus Maniculatus, Eutamias towendii, and Microtus sp. taken from roadsides, urban parklands, and wilderness areas revealed a significantly higher lead concentration in those animals taken from roadsides. No differences was found in hair from wilderness mammals and hair from specimens taken sixty years ago. (JWP)
Formulation of a nonlinear compatible finite element for the analysis of laminated composites

Abstract Increased use of laminated composites has pointed out the need for better analytic tools. These tools must be able to correctly account for normal shear in the laminates and should be able to solve nonlinear problems. The finite element method is applied in this paper to analyze laminated composites using an approach which includes both nonlinear and normal shear effects. A finite element is formulated from basic elasticity equations. The most unique characteristic of the element is the manner in which normal shear is handled. The normal to a reference surface is allowed to not only rotate but also to change shape. Not only is displacement continuity imposed at lamina interfaces, but also slope continuity is guaranteed. After a complete general formulation of the finite element is presented, the method is specialized to plates so that the convergence characteristics, the accuracy and the applicability of the element can be studied. The finite element does an excellent job of analyzing laminated composites, and gives the analyst the ability to do nonlinear analysis of laminated composites under a variety of loading and boundary conditions.
The relationship between selected scales of the Adjective Check List and musical creativity: A validation study

The purpose of this study was to determine whether personality characteristics associated with creativity in other samples of creative adults would distinguish a group of professional jazz musicians, selected for excellence of improvisational ability, from a group of professional symphonic musicians. A second purpose was to determine whether such differences found between these professional groups would also characterize groups of adolescent jazz and symphonic music students. In this regard, 60 male professional musicians (30 jazz and 30 symphonic) and 60 male student musicians (30 jazz and 30 symphonic) were asked to respond to items of the Adjective Check List (ACL). The ACL failed to distinguish between the jazz and symphonic players at every level of analysis—from two specific creativity scales, through profile analysis, and on down to the item level. These findings raise questions about the generalizability of the ACL creativity scales.
Effects of the Therapist's Nonverbal Behavior on Participation and Affect of Individuals with Alzheimer's Disease During Group Music Therapy Sessions

In healthcare settings, medical professionals' nonverbal behavior impacts patients' satisfaction and long-term physical, cognitive, and emotional well-being. The purpose of this research was to determine the effects of a music therapist's nonverbal behavior, affect and proximity, on participation and affect of 38 individuals with Alzheimer's disease and other related dementia (ADRD) during movement-to-music, singing, and instrument playing. Data indicated 62% of the individuals evinced positive affect when the therapist utilized affect and proximity combined, followed by the affect only condition (53%), proximity only condition (30%), and no affect or proximity condition (28%). A Friedman analysis indicated a significant difference in individuals' affect according to treatment conditions, chi(r)2 (3, 4) = 34.05, p = .001. Nonverbal behavior also impacted individuals' accuracy of participation, with participation at 79% for both affect and proximity combined, 75% for affect only, 71% for no affect or proximity, and 70% for proximity only. A significant difference occurred for participation by treatment conditions, F (3, 111) = 4.05, p = .009, eta2 = .10. Clinical implications are discussed.
3325 Unsedated colonoscopy performed primarily by trainees: results of a prospective randomized trial.

Background:Colonoscopy is usually performed with sedation. Little is known about patient(pt) tolerance of the procedure without medication.We performed a prospective, randomized trial of sedated vs. unsedated colonoscopy. To our knowledge, this is the first study of this issue in an academic setting with trainees performing exams. Methods:Consecutive outpatients were offered the study. Patients were randomized to receive sedation or to begin the procedure without sedation; medication was given upon request. A brief survey of symptoms(sx) was completed by all patients. After the exam, patients graded their satisfaction from 0-10. Recovery times were recorded. Exams were performed by senior fellows (experience range 108-696 exams) or an attending (24%). Results:142/384(37%)of patients agreed to enroll. 45% randomized to sedation (S); 55% to no sedation (NS). There was no difference between groups in terms of prior colonoscopy, age, or gender. There was no difference in procedure times (S=27 minutes, NS=26.5 minutes). Median satisfaction ratings were 10 (S) vs. 9 (NS), p=0.004. Recovery times were significantly shorter in the NS group, 16.5 minutes vs.55 minutes, p=0.0001. Of those randomized to NS, 23% required sedation to complete the exam. 71% of patients in the NS group who had had a prior colonoscopy stated they would undergo the procedure again without sedation. Sedation, but not sx or endoscopist experience, correlated with satisfaction. Endoscopist experience did not correlate with failure of NS exam. Pts with sx consistent with IBS were significantly less likely to complete the exam without sedation(p=0.04);10/10 of such pts randomized to NS required sedation to complete the exam. Conclusions:Unsedated colonoscopy is accepted by a significant proportion of patients. Even when colonoscopy is performed by trainees, the majority of pts (excluding those w/IBS) complete the exam w/acceptable satisfaction ratings and significantly shorter recovery times.
Low-Density Aerodynamics of the Stardust Sample Return Capsule

The aerodynamics of the Stardust Sample Return Capsule are analyzed in the low-density, transitional flow regime using free-molecular, Direct Simulation Monte Carlo, Navier-Stokes, and Newtonian methods to provide inputs for constructing a transitional flow bridging relation. The accuracy of this bridging relation in reconstructing the aerodynamic coefficients given by the more exact methods is presented for a range of flight conditions and vehicle attitudes. There is good agreement between the various prediction methods, and a simple sine-squared bridging relation is shown to provide a reasonably good description of the axial force, normal force, and pitching moment over a range of Knudsen numbers from 0.001 to 10. The predictions show a static instability of the Stardust capsule in the free-molecular regime that persists well into the transitional flow. The addition of a thin disk to the base of the capsule is shown to remove this static instability. However, the extremely high entry velocity of 12.6 km/s for the proposed trajectory introduces difficult design issues for incorporating this disk caused by the high aerothermal loads that occur even under relatively rarefied conditions.