cssi/SciSciGPT-SciSciNet huggingface dataset:
A remark on the flash temperature theory

The classical solution of the temperature development in a sliding solid pair treats the thermal conductivity as a non-variant quantity that is not affected by temperature elevation. This may introduce an erroneous estimate of the temperature distribution in the contacting pair. This error may be intensified in the presence of considerable temperature gradients. In this note, we apply the well known Kirchoff transformation to correct the temperature estimates in a practical case of sliding friction. Thus, accounting for the point wise variation of the thermal conductivity in the contacting pair. We compare temperature estimates, obtained by the classical solution, to those obtained by the variable conductivity solution. The results indicate that the behavior of the thermal conductivity with temperature is influential to the magnitude of the peak flash temperatures developed at the tip of the contact asperities.
The role of platelets in antimicrobial host defense.

Abstract Platelets exhibit archetypal structures and functions enabling their roles as multifunctional host defense cells. Beyond roles in hemostasis and wound repair, platelets sense and respond to pathogens through mechanisms including pattern recognition, early trafficking to sites of infection, direct antimicrobial functions, and potentiation of innate and adaptive immune mechanisms. Insufficient platelet quantity and dysfunctions in platelet quality increase the risk of infections or worsen severity. Moreover, certain pathogens may subvert the host defense functions of platelets, exploiting them in pathogenesis. Here, the immunobiology of platelets in antimicrobial host defense is reviewed from each of these perspectives.
Morphological observations on Brevipalpus phoenicis (Acari: Tenuipalpidae) including comparisons with B. californicus and B. obovatus.

The genus Brevipalpus has over 300 species worldwide. The three most important agricultural pest species in the genus, Brevipalpus californicus (Banks), B. obovatus Donnadieu, and B. phoenicis (Geijskes), have been consistently confused and misidentified for more than 50 years. The present study provides a discussion of the characters and character states used to separate these mites. Low-temperature scanning electron microscopy and traditional light microscopy techniques were used to illustrate the subtle morphological differences between these three species. Morphology of the dorsal propodosoma, opisthosoma, and leg chaetotaxy of all three species was examined and compared. The number of dorsal setae, the number of solenidia (omega) on tarsus II, and dorsal cuticular patterns were the most important characters in the identification of Brevipalpus species. B. phoenicis is similar to B. californicus in having two omega on tarsus leg II and different from B. obovatus which has only one omega on tarsus leg II and similar to B. obovatus in having only one pair of F setae (f3), but differing from B. californicus which has two pairs of F setae (f2–3). The dorsal opisthosomal and propodisomal cuticular patterns frequently used to distinguish between these three species are useful but one must be aware that age, feeding, and mounting techniques can affect the appearance of these characters.
Theoretical development of a Gaussian potential function in the description of the radial portion of isotropic bending vibrations

Analysis of a Gaussian potential function suitable for modeling degenerate bending vibrations in weakly bound molecular complexes is presented. Approximate eigenvalues and eigenvectors are obtained by application of perturbation theory. Comparison to the “exact” eigenvalues obtained via a numerical solution shows that the first- and higher-order perturbation corrections are consistent with variational principles.
Size and Dynamics of the Vibrio cholerae Porins OmpU and OmpT Probed by Polymer Exclusion

The trimeric OmpU and OmpT porins form large, triple-barrel hydrophilic channels in the outer membrane of the pathogen Vibrio cholerae. They have distinct pore properties, such as conductance, block by deoxycholic acid, and sensitivity to acidic pH. Their three-dimensional structures are unknown, but they share significant sequence homologies. To gain insight into the molecular basis for the distinct functional properties of these two similar porins, we carried out polymer exclusion experiments using planar lipid bilayer and patch-clamp electrophysiology. By studying the partitioning of polyethylene glycols (PEGs) of different molecular weights into each porin, we determined an effective radius of 0.55 nm and 0.43 nm for OmpU and OmpT respectively, and found an increased OmpU effective radius at acidic pH. PEGs or high buffer ionic strength promotes the appearance of single step closures in OmpU similar to the acidic-pH induced closures we documented previously. In addition, these closing events can be triggered by nonpenetrating PEGs applied asymmetrically. We believe our results support a model whereby acidic pH, high ionic strength, or exposure to PEGs stabilizes a less conductive state that corresponds to the appearance of an additional resistive element on one side of the OmpU protein and common to the three monomers.
Alteration of glucose consumption kinetics with progression of baculovirus infection in Spodoptera frugiperda cells.

We have used the initial-rate approach to characterize changes in the glucose consumption kinetics of baculovirus-infected Spodoptera frugiperda clone 9 (Sf9) cells with the progression of the infection process. The specific glucose consumption rate (q G) of cultured baculovirus-infected Sf9 cells was measured at 4, 8, 12, 16, and 24 h postinfection (h.p.i.) in media containing 4–35 mM glucose. Higher medium glucose concentrations resulted in higher final extracellular virus and recombinant β-galactosidase yields. q G was related to the extracellular glucose concentration by means of a Michaelis-Menten relationship. The apparent Michaelis-Menten constant (K m) for glucose consumption was found not to change significantly during the progression of the infection process, and remained between 6.2 and 7.2 mM. However, the maximal specific glucose consumption rate (q Gmax) was found to rapidly increase after infection, peaking at 16 h.p.i. at a value four times that for uninfected Sf9 cells. The kinetic analysis of glucose consumption rates in baculovirus-infected Sf9 cells presented here will aid in the optimal design and operation of bioreactor systems for the large-scale production of recombinant products from the baculovirus/insect cell system.
Endothelially derived nitric oxide affects the severity of early acetaminophen-induced hepatic injury in mice.

Objectives: The precise mechanism of hepatocellular toxicity following acetaminophen (APAP) poisoning remains unclear. Nitric oxide is implicated in APAP toxicity as an inflammatory signaling molecule and as a precursor to the free radical peroxynitrate. The effects of inducible nitric oxide synthase (iNOS)-derived NO in APAP toxicity are known; however, the role of endothelial nitric oxide synthase (eNOS)-derived NO is unknown. The authors sought to evaluate the effect of eNOS-derived NO during APAP toxicity. Methods: C57BL6/J mice deficient in eNOS (eNOS KO) or iNOS (iNOS KO) and wild-type mice (WT) were treated with 300 mg/kg APAP. Alanine aminotransferase levels and plasma nitrate and nitrite levels were measured. Hypoxia inducible factor (HIF)-1α and Glucose Transporter 1 (Glut-1) levels were determined by Western blot. Results: Alanine aminotransferase levels were significantly elevated in all treated animals. Alanine aminotransferase levels were significantly lower in eNOS KO and iNOS KO than in treated WT animals. Plasma nitrate/nitrite levels were significantly higher in WT animals than in iNOS KO and eNOS KO animals. HIF-1α expression was increased in WT mice and decreased in iNOS KO mice. Glut-1 is a downstream, indirect marker of HIF function. Glut-1 expression was increased in WT and eNOS KO mice. Conclusions: Deficiency of either iNOS or eNOS results in decreased NO production and is associated with reduced hepatocellular injury following APAP poisoning. HIF-1α and Glut-1 levels are increased following APAP poisoning, implying that HIF-1α is functional during the pathogenic response to APAP poisoning.
Rasch analysis of a Spanish language-screening parent survey.

Abstract The purpose of this study was to evaluate and refine items from a parent survey designed to screen the language skills of Spanish-speaking preschoolers. This investigation applied Rasch modeling to systematically evaluate and identify items that demonstrated favorable qualities. A set of 124 parent survey items was administered to 107 Spanish-speaking parents of preschool age children. Parents completed survey items intended to provide a global measure of preschool language abilities. Rasch analyses of the survey items were conducted using WINSTEPS. Results indicated that 59 items, all vocabulary items, fit the Rasch model. Sufficient unidimensionality was obtained, with the model accounting for 58% of the variance. Item difficulty estimates ranged from −7.43 to 4.12, with a shortage of items at both the lower ability level and at the higher ability level. Analyses of pruned and remaining items identified the type of items that may be most useful for a refined item bank. These results will inform the development of new items for a Spanish language-screening parent survey for preschool age children.
Genome-wide analysis of antiviral signature genes in porcine macrophages at different activation statuses.

Macrophages (MФs) can be polarized to various activation statuses, including classical (M1), alternative (M2), and antiviral states. To study the antiviral activation status of porcine MФs during porcine reproductive and respiratory syndrome virus (PRRSV) infection, we used RNA Sequencing (RNA-Seq) for transcriptomic analysis of differentially expressed genes (DEGs). Sequencing assessment and quality evaluation showed that our RNA-Seq data met the criteria for genome-wide transcriptomic analysis. Comparisons of any two activation statuses revealed more than 20,000 DEGs that were normalized to filter out 153–5,303 significant DEGs [false discovery rate (FDR) ≤0.001, fold change ≥2] in each comparison. The highest 5,303 significant DEGs were found between lipopolysaccharide- (LPS) and interferon (IFN)γ-stimulated M1 cells, whereas only 153 significant DEGs were detected between interleukin (IL)-10-polarized M2 cells and control mock-activated cells. To identify signature genes for antiviral regulation pertaining to each activation status, we identified a set of DEGs that showed significant up-regulation in only one activation state. In addition, pathway analyses defined the top 20–50 significantly regulated pathways at each activation status, and we further analyzed DEGs pertinent to pathways mediated by AMP kinase (AMPK) and epigenetic mechanisms. For the first time in porcine macrophages, our transcriptomic analyses not only compared family-wide differential expression of most known immune genes at different activation statuses, but also revealed transcription evidence of multiple gene families. These findings show that using RNA-Seq transcriptomic analyses in virus-infected and status-synchronized macrophages effectively profiled signature genes and gene response pathways for antiviral regulation, which may provide a framework for optimizing antiviral immunity and immune homeostasis.
Effect of penicillamine upon healing wounds.

Abstract Two groups of paired male Cobbs rats weighing about 175 gm. were submitted to a dorsal skin incision according to a standard procedure, and polyvinyl alcohol sponges were implanted subcutaneously. The animals ate a normal chow ad libitum preoperatively and for a period of 6 weeks postoperatively. After this, d l penicillamine and pyridoxine were added to the diet of one group; the other group continued on the basal diet. After 4 weeks (10 weeks after operation) the animals were killed and the wounds and sponge granulomas analyzed. We found that feeding penicillamine caused a 52% reduction in the strength of the skin incisions and a 34% decrease in unwounded skin strength when both were tested in the fresh state. After fixation in 10% formalin, the strength of the wounds of both groups was identical. The histological appearance of the wounds and granulomas was similar in both groups. The collagen content of the granulomas was the same for each group, but a higher percentage of this was present in the neutral salt-soluble fraction of the collagen from penicillamine-fed animals, as compared to the control group. It was concluded that the ingestion of penicillamine prevents the cross-linking of collagen as it is being synthesized and also reverses certain cross-links of collagen already present. The former effect is the more pronounced.
Inhibition of human glutamine synthetase by L-methionine-S,R-sulfoximine-relevance to the treatment of neurological diseases.

At high concentrations, the glutamine synthetase inhibitor L-methionine-S,R-sulfoximine (MSO) is a convulsant, especially in dogs. Nevertheless, sub-convulsive doses of MSO are neuroprotective in rodent models of hyperammonemia, acute liver disease, and amyotrophic lateral sclerosis and suggest MSO may be clinically useful. Previous work has also shown that much lower doses of MSO are required to produce convulsions in dogs than in primates. Evidence from the mid-20th century suggests that humans are also less sensitive. In the present work, the inhibition of recombinant human glutamine synthetase by MSO is shown to be biphasic—an initial reversible competitive inhibition (K i 1.19 mM) is followed by rapid irreversible inactivation. This K i value for the human enzyme accounts, in part, for relative insensitivity of primates to MSO and suggests that this inhibitor could be used to safely inhibit glutamine synthetase activity in humans.
Ontogeny of ovine fetal renal atrial natriuretic factor receptors.

Abstract Ovine fetal renal responses to ANF decrease during the last third of gestation, although circulating fetal plasma atrial natriuretic factor (ANF) levels are higher than in the maternal circulation, and do not change with gestation. This study examined whether previously reported maturational changes in fetal renal responses to ANF are due to changes in renal ANF receptor numbers and/or affinity during gestation. ANF receptor numbers (Bmax) and dissociation constants (Kd) were measured in isolated renal glomeruli from early (95 and 110 day; mean 103±2) and late gestation (131 and 145 day; mean 138±2) fetal and maternal sheep. Fetal renal ANF receptor Bmax values significantly increased between 103 and 138 days gestation (13±3 to 29±4 fmol/mg protein) but were significantly lower than maternal values (60±13 fmol/mg protein). Fetal ANF receptor Kd values also increased significantly (245±34 to 370±36 pM), with early gestation values significantly lower than maternal values (470±69 pM). Thus, the blunted fetal renal response to ANF in late as compared to early gestation is not due to reduced ANF receptor numbers. Rather, an increased proportion of ANF clearance receptors, reduced post-receptor function and/or altered intrarenal hemodynamics may contribute.
Study of the genetically complex epilepsies

Identifying the genes that influence risk for genetically complex epilepsies is a major challenge for the next decade. This chapter reviews possible biologic mechanisms, methodologic approaches, and findings from recent studies aimed at gene identification in complex epilepsies, and approaches for clarifying phenotype definition for genetic research on the epilepsies. For an expanded treatment of this topic see Jasper's Basic Mechanisms of the Epilepsies, Fourth Edition (Noebels JL, Avoli M, Rogawski MA, Olsen RW, Delgado-Escueta AV, eds) published by Oxford University Press (available on the National Library of Medicine Bookshelf [NCBI] at www.ncbi.nlm.nih.gov/books).
In Search of a Further Frontier: Cormac McCarthy's Border Trilogy

Abstract In 1998, McCarthy published the third volume of his Border Trilogy, Cities of the Plain, in which the protagonists of the previous two volumes, John Grady Cole and Billy Parham, are brought together; their previously disparate narratives intersect, effecting the trilogy's thematic unification. In the first two works, Cole and Parham, feeling the encroachment of increasing urbanization, leave the American Southwest to seek a simpler, more pastoral existence in Mexico. However, in the third novel the pastoral dream of an idyllic life on the edge of the Mexican frontier is superseded by the grim reality of the corrupt border city of Juarez and its American counterpart, El Paso. Accordingly, by the end of Cities of the Plain it becomes clear that McCarthy's trilogy chronicles the death of the traditional American pastoral dream.
Grid active power filters using cascaded multilevel inverters with direct asymmetric switching angle control for grid support functions

This paper presents a new control technique for cascaded multilevel inverters, which can achieve harmonic and reactive power compensation and balance unbalanced load simultaneously. Unlike existing control strategies which work in the time domain and focus on reducing the overall harmonics and reactive power without differentiating individual harmonics, this new method works in the frequency domain and can efficiently compensate individual harmonics and reactive power apart from balancing unbalanced load. The principle of the proposed technique is to compensate harmonics and reactive power and balance unbalanced load with direct asymmetric firing angle and conduction angle control for each H-bridge of multilevel inverter. To verify the effectiveness of this new technique, genetic algorithm (GA) is used to solve transcendental equations and find switching angles of each H-bridge of multilevel inverter. From the simulation results, it can be seen that the proposed technique can not only achieve the same harmonic and reactive power compensation performance with a much lower switching frequency than traditional control methods of cascaded multilevel inverter based active power filter (APF), but also can balance unbalanced loads successfully at the same time.
Parton-hadron duality: Resonances and higher twists.

We explore the physics of parton-hadron duality in the nucleon structure functions measured in lepton-nucleon scattering. We stress that duality allows one to extract the higher-twist matrix elements from data in the resonance region, or conversely to learn about the properties of resonances if the matrix elements are known. As an example, we construct the moments of ${\mathit{F}}_{2}$(x,${\mathit{Q}}^{2}$) for the low and medium ${\mathit{Q}}^{2}$ region, and from which we study the interplay between higher twists and the resonance contributions.
Proton exchange and protonation of substituted oxadiazoles in trifluoroacetic acid

The rates of NHCOOH proton exchange between 5-amino-(1a) and 5-N-methylamino-(1b)3-[2-(5′-nitro-2′-furyl)vinyl]-1,2,4-oxadiazoles and trifluoroacetic acid (TFA) have been measured by NMR spectroscopy. The values of the first-order rate constant and thermodynamic parameters for 1a and 1b, respectively, are: kapp (sec−1) = 820 and 40 (50°C), ΔF (kcal/mole) = 14·7 and 16·5, ΔH# (kcal/mole) = 17·3 and 24·3 and ΔS# (e.u.) = 17 and 34. The comparison of rate constants indicates that after correction for proton equivalency proton exchange in 1a is faster than in 1b by a factor of ten. The presence of an NH2 proton resonance (1a) and an N-methyl doublet (J = 5·0 Hz) between 0 and 30° (1b) suggests that 1a and 1b are present as amines and not as imines in TFA.
Evidence for the existence of two classes of corncob (coaggregation) receptor in Fusobacterium nucleatum.

Oral isolates of Fusobacterium nucleatum have the ability to form distinct coaggregation units, termed corncobs, when mixed with Streptococcus sanguis. Saturation binding kinetics determined for 12 strains of F. nucleatum revealed that these strains could be divided into two groups. One group, represented by F. nucleatum ATCC 10953 reproducibly bound twice as many streptococci as the other group, exemplified by F. nucleatum FDC 364. Other Fusobacterium species tested, including F. mortiferum, Fusobacterium periodonticum, Fusobacterium simiae and Fusobacterium necrophporum, failed to form corncobs with S. sanguis. In inhibition experiments lipoteichoic acid (LTA)-enriched cell extracts from S. sanguis blocked corncob formation between this bacterium and strain FDC 364 with material containing as little as 50 ng phosphate exhibiting greater than 50% inhibition. Alternatively, 40 times as much material failed to inhibit corncob formation between S. sanguis and F. nucleatum ATCC 10953 or Bacterionema matruchotti. Deacylation of the LTA destroyed its ability to inhibit the fusobacterial coaggregation but produced an active inhibitor in the case of B. matruchotii corncobs. Concerning the fusobacterial coaggregation partner, membrane fractions obtained from strain ATCC 10953 blocked corncob formation while the inhibitory activity of strain FDC 364 was confined to the soluble protein fraction. Corncob-deficient mutants of F. nucleatum FDC 364 were produced by treating the cells with acridine orange. However, this agent had no effect on the corncob-forming ability of strain ATCC 10953. The results of these experiments provide convincing evidence that at least 2 independent strain-specific receptors on F. nucleatum are involved in corncob formation between this bacterium and S. sanguis.
Sperm competition and sex allocation in simultaneous hermaphrodites

Sex allocation theory is developed for hermaphrodites having frequent copulations and long-term sperm storage. Provided the sperm displacement mechanisms are similar to those known in insects, the ESS allocation to sperm versus eggs satisfies a rather simple rule. There are no data to test this rule, as yet.
Straightening of Crimped and Hooked Fibers in Converging Transport Ducts: Computational Modeling:

A two-dimensional dynamics model for the motion of fibers in an accelerating laminar air flow is presented. Nonlinear model equations for each fiber include effects of inertia, air drag, and flexural rigidity. This rigidity, or stiffness, acts in such a way that a curled or hooked fiber resists being straightened. Randomly distributed fiber crimps at the inlet can be preferentially straightened as the fibers are transported in two converging ducts. Statistical measures of straightening are provided.
Life-Cycle Costs of Housing for the Mentally Ill

Abstract This paper estimates the life-cycle costs of housing for persons with mental illness using 5-year and 30-year holding periods and discount rates of 3.5, 5.75, and 8.0%. Life-cycle costs are between 5 and 7% higher in buildings occupied only by mentally ill tenants compared to buildings with no mentally ill tenants. However, the economies of scale in maintenance and repair that exist in buildings occupied by the non-mentally ill are not observed in buildings with mentally ill tenants. Additionally, buildings located in lower-quality neighborhoods have lower life-cycle costs when the tenants are mentally ill, just the reverse of the case for the general population.
Venous thromboembolism prophylaxis in the pediatric trauma population.

Abstract Background/Purpose The aim of this study was to review evidence-based literature addressing pertinent questions about venous thromboembolism (VTE) after traumatic injury in children. Methods Data were obtained from English-language articles identified through Pubmed published from 1995 until November 2012, and from bibliographies of relevant articles. Studies were included if they contributed evidence to one of the following questions. In the pediatric traumatic injury population: (1) What is the overall incidence of VTE? (2) Is age (adolescence versus pre-adolescence) associated with higher VTE incidence? (3) Which risk factors are associated with higher VTE incidence? (4) Does mechanical and/or pharmacological prophylaxis impact outcomes? Results Eighteen articles were included in this systematic review. The evidence regarding each question was evaluated, graded by author consensus, and summarized. Conclusions The overall incidence of VTE is low. Older (>13years) and more severely injured patients are at higher VTE risk. Additional factors including injury type or presence of a central venous catheter also place a patient at higher VTE risk. Implementation of a risk-based clinical practice guideline for VTE prophylaxis has been associated with reduced symptomatic VTE at one institution. Randomized, prospective trials analyzing outcomes of VTE prophylaxis in pediatric trauma victims are needed.
A quasilinear theory of ion “thermalization” and wave excitation downstream of Earth's bow shock

[1] A quasilinear theory is presented for the relaxation of the proton and helium distribution functions and the associated excitation of ion cyclotron waves, downstream of the quasi-perpendicular Earth's bow shock. The theory predicts the wave polarization, power and peak frequency, and the proton bulk velocity and temperature anisotropy, sufficiently far downstream of the shock that the ions and waves have relaxed to a quasi-equilibrium. The results are compared with the AMPTE/IRM crossings of the marginally supercritical bow shock documented by Sckopke et al. (1990), for which the number of “reflected” protons is small and the quasilinear approximation is expected to be valid. The theory starts with the trajectories of the specularly reflected protons and transmitted helium in the laminar electromagnetic fields of the shock transition. In a simplified treatment of the downstream relaxation process, neglecting wave dispersion and assuming that the downstream reflected proton speed v0 is large compared with the Alfven speed VA, the wave and proton quasi-equilibrium predictions are qualitatively in agreement with the observations. In a more precise treatment limited to a perpendicular configuration, in which dispersion is included and v0 may be comparable with VA, the agreement with the observations is generally very good if the contribution of the transmitted core protons is included. One interesting feature is that the minor ion helium may contribute to the wave power, and in return change the proton and helium distribution functions. The helium contribution is estimated but requires further investigation.
Can We Lead and Follow

Abstract:This article contributes to organizational efficacy by exploring the role of followers as part of the leadership development process. The idea of leaders in organizations has been discussed and cussed ad infinitum by practitioners, researchers, and observers. With a growing recognition of organizational followers as a backdrop, this article reports on basic research comparing attributes of leaders and followers and seeks to provide recommendations for enhancing the leadership development process in engineering organizations. Using theories proffered by Sashkin (Visionary Leadership) and Chaleff (Courageous Followers) as an experimental framework, data was collected from technology workers (N = 111) and analyzed to ascertain the nature of leader-follower correlations in an effort to further explore intrapersonal leader-follower relations and exchange. The analysis indicates the concepts are correlated. Based on the correlation, recommendations are provided for the leadership development process.
Ordering in thermally oxidized silicon.

We present new evidence and a model for residual ordering of silicon atoms within the oxide of thermally oxidized silicon wafers. X-ray scattering is used to observe the residual order in thermally grown ${\mathrm{S}\mathrm{i}\mathrm{O}}_{2}$ on Si(001), (011), and (111) surfaces with thicknesses of 60 to 1000 \AA{}, for both on-axis and miscut surfaces. In every case, the scattering position can be predicted using a model which expands the silicon lattice during oxidation without completely disordering it. The amount of expansion and disorder is dependent on the type of oxidation process employed.
Distributed transducer shading: application to structural control, hydrodynamics, and sonar sensing

A general mathematical model of distributed transducer shading, or spatial gain-weighting, is developed for 1-D distributed actuators and sensors, valid for both strain and hydrostatic mode devices. Means for constructing shaded distributed actuators and sensors using shaped electrodes are reviewed. Singularity functions and other complete sets of functions are used to parameterize shadings. Modal and wavenumber interpretations of shading kernels are deduced. Hardware applications are presented from structural control, hydrodynamics, and high- resolution sonar sensing. A conformal, real-time hydrodynamic center of pressure sensor is described. A novel sonar sensor is presented that utilizes two coincident, distributed, shaded piezopolymer sensors to provide high-resolution target bearing estimates. In each of these applications, sensor shading is accomplished by suitably shaping the charge collection electrodes deposited on the sensing layer to provide two coincident distributed devices having a prescribed mathematical relationship spatially, yielding devices that cannot be realized using either discrete or unshaded distributed transducers.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Multiple perspectives on online learning

This paper advocates an approach to the design, use and impact of new learning technologies that incorporates the view from multiple perspectives. This includes considering the questions and goals of students, faculty, administrators and co-workers, as well as social dimensions of learning, professional socialization, family dynamics, career, community formation, and institutional change.
Science and Technology Studies Saves Planet Earth via Latour

This book is about the exhaustion of fossil fuels and the disposal of toxic waste. It is about global warming and rainforest depletion too even though Bruno Latour never says a word specifically about these environ mental controversies. His agenda is to provide a new philosophical founda tion for 'political ecology'. The project is surely ontological, as Latour dispenses with such useless distinctions as things versus humans. It is also epistemological, as Latour knocks scientists off their pedestals as privileged purveyors of truth. The narrow academic world of Science and Technology Studies (STS) which Latour has done so much to cultivate is presented here as the foundation on which the survival of the planet precariously rests. He asks nothing less than this: can we ever figure out how to live together in one common world? Politics of Nature is fresh and programmatic, extending in new direc tions themes explored sometimes cryptically in We Have Never Been Modern (Latour, 1993). The book will disappoint those looking for an empirically grounded analysis. Unlike Aramis (Latour, 1996) or The Pasteurization of France (Latour, 1988), 'data' in Politics of Nature come in the form of aper?us, asides, and casual readings of the global media. Predictably, the book is full of schematics designed to show how science and politics must be ripped out of their comfortable interpretations and reorganized into new boxes and ovals for greater potency. Latour hopes to rescue democracy by escaping from the modernist illusions that have made it impossible. He returns readers to Plato's allegory of the cave. Inside the cave is darkness here is society, with its
Ex vivo γ-retroviral gene therapy of dogs with X-linked severe combined immunodeficiency and the development of a thymic T cell lymphoma.

We have previously shown that in vivo γ-retroviral gene therapy of dogs with X-linked severe combined immunodeficiency (XSCID) results in sustained T cell reconstitution and sustained marking in myeloid and B cells for up to 4 years with no evidence of any serious adverse effects. The purpose of this study was to determine whether ex vivo γ-retroviral gene therapy of XSCID dogs results in a similar outcome. Eight of 12 XSCID dogs treated with an average of dose of 5.8 × 106 transduced CD34+ cells/kg successfully engrafted producing normal numbers of gene-corrected CD45RA+ (naive) T cells. However, this was followed by a steady decrease in CD45RA+ T cells, T cell diversity, and thymic output as measured by T cell receptor excision circles (TRECs) resulting in a T cell lymphopenia. None of the dogs survived past 11 months post treatment. At necropsy, few gene-corrected thymocytes were observed correlating with the TREC levels and one of the dogs was diagnosed with a thymic T cell lymphoma that was attributed to the gene therapy. This study highlights the outcome differences between the ex vivo and in vivo approach to γ-retroviral gene therapy and is the first to document a serious adverse event following gene therapy in a canine model of a human genetic disease.
Surface phospholipids in gastric injury and protection when a selective cyclooxygenase‐2 inhibitor (Coxib) is used in combination with aspirin

Background and purpose: Clinical studies demonstrate that aspirin consumption reverses the gastrointestinal (GI) benefits of coxibs, by an undefined mechanism. Experimental approach: Rodent models were employed to investigate the effects of combinations of celecoxib and aspirin on gastric ulcerogenesis, bleeding, surface hydrophobicity (by contact angle analysis) and ulcer healing. We also evaluated the effects of phosphatidylcholine (PC)-associated aspirin in these rodent models and confirmed its cyclooxygenase (COX)-inhibitory activity by measuring mucosal prostaglandin E2 (PGE2) concentration. Key results: We present evidence that aspirin's ability to induce gastric injury and bleeding in rats, was exacerbated in the presence of a coxib and was dependent on its ability to reduce gastric surface hydrophobicity. In contrast, co-administration of phosphatidylcholine (PC)-associated aspirin and celecoxib induced little or no gastric injury/bleeding and maintained the stomach's hydrophobic properties. Interestingly, aspirin and aspirin/PC equally inhibited gastric mucosal PGE2 concentration. Aspirin in combination with a coxib retarded the healing of experimentally induced gastric ulcers, whereas healing rates of rats treated with celecoxib in combination with aspirin/PC were comparable to controls. Conclusions and implications: Aspirin's gastric toxicity in combination with a coxib can be dissociated from its ability to inhibit COX-1 and appears to be dependent, in part, on its ability to attenuate the stomach's surface hydrophobic barrier. This adverse drug interaction between aspirin and coxibs, which impacts the treatment of osteoarthritic and cardiac patients requiring cardiovascular prophylaxis, can be circumvented by the administration of phosphatidylcholine (PC)-associated aspirin, to maintain the stomach's hydrophobic properties. British Journal of Pharmacology (2007) 150, 913–919. doi:10.1038/sj.bjp.0707176
Taxon‐specific associations between protozoal and methanogen populations in the rumen and a model rumen system

Methanogen populations in the rumen and in model rumen systems (operated over a 240-h period) were studied using the small subunit (SSU) rRNA phylogenetic framework for group-specific enumerations. Representatives of the family Methanobacteriaceae were the most abundant methanogen population in the rumen, accounting for 89.3% (± 1.02%) of total archaea in the rumen fluid and 99.2% (± 1.8%) in a protozoal fraction of rumen fluid. Their percentage of archaea in the model rumen systems declined from 84% (± 8.5%) to 54% (± 7.8%) after 48 h of operation, correlated with loss of protozoa from these systems. The Methanomicrobiales, encompassed by the families Methanomicrobiaceae, Methanocorpusculaceae, and Methanospirillaceae were the second most abundant population and accounted for 12.1% (± 2.15%) of total SSU rRNA in rumen fluid. Additionally this group was shown to be essentially free living, since only a negligible hybridization signal was detected with the ruminal protozoal fraction. This group constituted a more significant proportion of total archaea in whole rumen fluid, 12.1% (± 2.1%) and model rumen fluid containing no protozoa (26.3 ± 7.7%). In contrast, the Methanosarcinales, generally considered the second most abundant population of rumen methanogens, accounted for only 2.8% (± 0.3%) of total archaeal SSU rRNA in rumen fluid.
Molecular Dynamics Simulations of Helix-Forming, Amine-Functionalized m-Poly(phenyleneethynylene)s

We present here the results of all-atom and united-atom molecular dynamics (MD) simulations that were used to examine the folding behavior of an amine-functionalized m-poly(phenyleneethynylene) (m-PPE) oligomer in aqueous environment. The parallelized GROMACS MD simulation code and OPLS force field were used for multiple MD simulations of m-PPE oligomers containing 24 phenyl rings in extended, coiled and helix conformations separately in water to determine the minimum energy conformation of the oligomer in aqueous solvent and what interactions are most important in determining this structure. Simulation results showed that the helix is the preferred minimum energy conformation of a single oligomer in water and that Lennard-Jones interactions are the dominant forces for the stabilization of the helix. In addition, these solvophobic interactions are strong enough to maintain the helix conformation at temperatures up to 523 K.
Transition noise analysis of thin film magnetic recording media

A simple but accurate expression for general non-stationary noise correlation in the presence of a recorded transition is analyzed in terms of both noise voltage and spectral measurements. The parameters of this analysis are solely the cross track correlation width s, the transition shape and parameter a, the head-medium spacing d, and the replay gap length g. It is shown that although the noise varies continuously through the transition, a reasonable decomposition that accounts for a large percentage of the total noise is into conventional position and amplitude jitter of a fixed transition shape. The relative weights depend on the head-medium parameters; for current head-medium configurations and for longitudinal recording, position jitter dominates. A simple closed form expression for the noise power spectrum is given. Published experimental measurements of signal and noise spectra made with pseudo-random write data compare extremely well with this theoretical analysis, and lead to very good estimates for a and s. The analysis is general and applies for low-density recording with both inductive and magnetoresistive heads as well as all magnetization orientations. >
Bird community ecology on power-line corridors in East Tennessee☆

Abstract Breeding bird density and vegetation structure were determined during three breeding seasons in 14 plots on power-line corridors through forests in East Tennessee. The purpose was to describe the corridor bird community and to relate bird density and diversity to a number of environmental variables. The relative abundance of forbs, blackberry Rubus ssp., saplings, and areas of planted grasses varied significantly among plots. Thirteen bird species appeared to be attracted to the corridors. Seven of these species were classified as brush species, three as edge species, and three as generalist species, depending on their relative abundance in corridor, edge, and forest, respectively. Control of bird community density on the corridors was complex because individual species densities correlated significantly with several different variables. These variables were Rubus density and patchiness, sapling density and patchiness, corridor width, length of coniferous or deciduous forest edge, coverage of planted grasses, and number of years following vegetation maintenance by cutting. Bird community density varied among plots from 210 to 750 pairs km−2, and increased asymptotically with Rubus density. Rubus density explained most of the variation and Rubus patchiness explained a significant additional portion. Species number varied little. Within plots, birds were registered significantly less often in grass-dominated areas than in forb-Rubus-dominated areas.
Topographically discounted Internet infrastructure resources: a panel study and econometric analysis

The Internet infrastructure is increasingly utilized for the provision and delivery of a variety of services. The rapid growth and substantial demand fluctuations of the supported services are placing strain on the service providers to effectively manage their infrastructure resources. Capacity Provision Network (CPN) is a market-driven mechanism that enables the service providers to efficiently allocate, share and trade service capabilities. Central to the operation of CPN is the notion of discounted capacities which capture the underlying topology of the Internet. It serves as a practical instrument for service providers to evaluate the utility of capacity services available at remote sites vis-a-vis the capacities available locally and from the content providers. We conducted an Internet based longitudinal field experiment to empirically assess and validate the critical properties of discount factors. Our analysis reveals that discount factors exhibit markedly lower volatility than network delays, and are more stable over seasonal and temporal trend patterns. The results related to size effects suggest that sharing and trade agreements with larger content can be particularly effective. Our finding on the existence of the concavity property points to the ability of intermediation services to enhance the overall gains from resource sharing arrangements.
Preliminary characterization of the estrogen binding protein from bovine and porcine hypothalamus.

Abstract Low salt buffer extracts of fresh bovine or porcine hypothalamus contain a high affinity, low capacity estrogen binding protein (EBP) which is similar to EBP from other estrogen target tissues. It has a 7.8S sedimentation coefficient, an affinity of 6.2 × 10 9 M −1 for 3 H estradiol and a capacity of 5 × 10 −15 moles/mg protein. Like rat hypothalamic and calf uterine EBP, bovine and porcine EBP is a high molecular weight protein which chromatographs in the void volume on Sephadex G-200. Utilizing recent advances in EBP purification bovine or porcine hypothalamus could serve as a source for the purification of EBP from neural tissue.
Kinetics of the reaction of oxygen with carbon monoxide adsorbed on palladium*1

A study of the kinetics of the reaction of adsorbed carbon monoxide with oxygen on polycrystalline palladium is reported in which a pressure jump method was used to induce transients in the carbon dioxide production. Through an analysis of these transients under a variety of conditions of temperature and oxygen pressure, some details of the kinetics have been delineated. At relatively low temperatures and under a significant O2 pressure, CO(a) is desorbed more readily as CO2, via the reaction CO(a) + O(a) → CO2, than as CO. The reaction is first order in oxygen and the rate is limited by the rate of adsorption of oxygen onto sites which are in close proximity to CO(a). Oxygen adsorption at sites which are further than a critical distance from CO(a) are unreactive. The critical distance increases with temperature reflecting increased mobility. Under conditions where both CO(a) and O(a) are significant and both CO(g) and O2(g) are small the rate is limited by the mobility of CO(a) and/or O(a). The amount of CO(a) during the course of the steady-state oxidation reaction can be determined by analyzing the transient CO2 production which occurs following a pressure jump in carbon monoxide.
Employing multiple representations for Chinese information retrieval

For information retrieval in the Chinese language, three representation methods for texts are popular, namely: 1-gram or character, bigram, and short-word. Each has its advantages as well as drawbacks. Employing more than one method may combine advantages from them and enhance retrieval effectiveness. We investigated two ways of using them simultaneously: mixing representations in documents and queries, and combining retrieval lists obtained via different representations. The experiments were done with the 170 MB evaluated Chinese corpora and 54 long and short queries available from the (TREC) program and using our Probabilistic Indexing and Retrieval Components System (PIRCS retrieval system). Experiments show that good retrieval need not depend on accurate word segmentation; approximate segmentation into short-words will do. Results also show and confirm that bigram representation alone works well; mixing characters with bigram representation boosts effectiveness further, but it is preferable to mix characters with short-word indexing which is more efficient, needs less resource, and gives better retrieval more often. Combining retrieval lists from short-word with character representation and from bigram indexing provides the best retrieval results but also at a substantial cost.
End-user control environments and the accounting managers' perceived quality of the applications

Abstract The availability of powerful application developments tools has raised important questions about the extent to which control can and should be administered over end-user developers. This study examines the relationships among four factors hypothesized to be relevant to the control of end-user computing and the quality of such applications. The variables examined were end-user application quality, the extent of management concern about end-user computing issues, the extent of the organizational control environment, and the impact of resulting applications. Management concern about end-user control was shown to have a positive linear relationship with application impact, control environment, and application quality. There was no support for the hypothesis that a more extensive control environment is related to higher application quality.
Expression of two cytochromes P450 involved in carcinogen activation in a human colon cell line.

Cytochrome P450 is known to cause carcinogen activation and correspondingly increased cancer risk in animal models. In order to determine whether P450 in the colon may be involved in cancer development in the human, the human colon cell line LS174T was examined for the presence of various cytochromes P450. Two isozymes of P450 were identified in the human cell line. Expression of P450IAl or IA2 was increased by treatment of the cell line with benzanthracene; the induction was demonstrated by an increase in RNA hybridizing to a probe for P4501Al and by ethoxyresorufin deethylation activity. Western analysis of microsomes isolated from human colon tissue also demonstrated the presence of P4501A1, as well as a form which cross-reacted to an antibody to human P450IIC9. Another isozyme, P450IIE1, was identified by polymerase chain reaction amplification of RNA from LS174T cells. These results underscore the presence of cytochromes P450 in colonic tissue and provide a basis for the involvement of isozyme-specific P450 mediated reactions in carcinogenesis of the colon.