cssi/SciSciGPT-SciSciNet huggingface dataset:
Sectors and Large-Scale Magnetic Field Strength Fluctuations in the Heliosheath Near 110 AU: Voyager 1,2009

This paper describes observations of daily averages of the magnetic field strength B and the magnetic polarity measured by Voyager 1 (V1) in the heliosheath during 2009 between 108.5 and 112.1 AU and at heliographic latitude 34. . 4. A negative magnetic polarity sector was observed during 2009 DOY 43.255. A positive polarity sector was observed during 2009 DOY 256.365. We offer the hypothesis that the existence of the two sectors is the result of the displacement of the wavy heliospheric current sheet to the position of V1 as a result of northward flow in the heliosheath. The large size of the sectors is caused by the slow radial motion of the flow observed by V1 in the heliosheath. The distribution of B during 2009 was lognormal, in contrast to the Gaussian distributions observed by V1 in the heliosheath prior to 2009. The large-scale fluctuations of B, described by the distribution of increments of daily averages of B, have a Tsallis distribution with q = 1.6. The large-scale fluctuations of B observed by V1 during 2009 have a multifractal spectrum with the same parameters that V1 observed during 2005 close to the termination shock at 94 AU. These results suggest that the large-scale magnetic fluctuations of B are in a metastable equilibrium state in the heliosheath between 94 AU and 112.1 AU.
Modeling of supercritical oxidation of aqueous wastes in a deep-well reactor

A mathematical model is developed for deep-well oxidation of wastes in supercritical water. The model accounts for the variation of thermodynamic and transport properties with temperature and pressure. It is used to examine the steady-state behavior of the supercritical-water deep-well oxidation reactors. The effects of inlet flow rate, heat losses from the reactor, inlet concentration of organics, oxygen injection depth, reactor length, inlet pressure, and inlet temperature on the exit conversion and the bottom temperature are examined. The simulations show that under practical conditions the capacity of the reactor is dictated by hydrodynamic considerations rather than the oxidation kinetics, and that obtaining temperatures of 10 to 50 K above critical temperature at the bottom of the reactor requires longer tubes and/or high inlet pressures. Heat losses to the earth can be modeled accurately by treating the earth as an infinite reservoir by properly choosing the effective heat-transfer coefficient.
Case Report Neuronal Migration Disorder Associated With Chromosome 15q13.3 Duplication in a Boy With Autism and Seizures

Neuronal migration disorders are a group of disorders that cause structural brain abnormalities and varying degrees of neurocognitive impairment, resulting from abnormal neuronal migration during brain development. There are several mutations that have been associated with these disorders. Here the case of a 4-year-old autistic boy is presented, who was found to have evidence of a neuronal migration disorder on magnetic resonance imaging (MRI) during a workup for seizures. Genetic testing did not reveal any of the gene mutations known to be associated with neuronal migration disorders but did reveal a microduplication at chromosome 15q13.3, a locus that has been previously associated with autism, cognitive impairment, and seizures. Although the concurrent presence of the genetic and structural abnormalities does not necessarily imply causality, the simultaneous independent occurrence of both conditions is certainly unusual. It is possible that there may be an association between this duplication syndrome and aberrant neuronal migration.
Effects of prolonged perfusion time on the isolated perfused rat heart

Abstract Hearts from normal male rats were perfused with Krebs-Ringer bicarbonate buffer by the Langendorff method for periods ranging from 0–4 hr following an initial 15-min equilibration period. Spontaneous heart rate began to decrease by 30 min, whereas changes in coronary flow were not evident until after approximately 2 hr of perfusion. A reduction in isometric systolic tension was evident by 1 hr; after 4 hr of perfusion, tension was 35% of control. Cardiac glycogen concentrations became significantly different from control after 3 hr of perfusion, and at the end of 4 hr had decreased to 33% of control. Adenosine-5′-triphosphate content of hearts was not significantly different from control until perfused for 4 hr. In contrast, creatine phosphate concentrations decreased approximately 50% during the first hour of perfusion but remained constant thereafter. Prolonged perfusion (4 hr) caused no alteration in cardiac phosphorylase activity nor was there evidence of gross or microscopic lesions in the heart.
The effects of plant growth regulators on cellulase production by Trichoderma reesei

The plant growth regulators, indole-3-acetic acid (IAA) and gibberellic acid (GA3), were tested for their effects on spore germination and cellulase (B-1,4-endogluconase) production by Trichoderma reesei. The addition of 105 M IAA or GA3 enhanced cellulase production, whereas higher concentrations were inhibitory, both to spore germination and cellulase production.
Effect of hydroxypropyl-β-cyclodextrin on the central stimulant activity of (-)-ephedrine and an oxazolidine prodrug in rats

1. Hydroxypropyl-beta-cyclodextrin (HP-beta-CD) increases the stability of the oxazolidine prodrug toward hydrolysis. 2. The binding constant (Kb) and rate constant (Kc) for the hydrolysis of the prodrug-HP-beta-CD complex were calculated from the kinetic data. 3. Ion-spray mass spectra confirmed prodrug-HP-beta-CD complexation. 4. Mass spectral and kinetic data indicated 1:1 stoichiometry for the complex. 5. A significant elevation of locomotor activity in rats was observed when either (-)-ephedrine or the prodrug was administered by either the intraperitoneal or the oral route. 6. Addition of HP-beta-CD potentiated the central nervous system effect of both (-)-ephedrine and the prodrug when administered intraperitoneally. However, when the drugs were administered orally, HP-beta-CD caused a decrease in activity.
Nanoparticle targeting using multivalent ligands: computer modeling

Using Monte Carlo simulations, we analyze the efficiency in targeting mobile receptors on cell surfaces by nanoparticles carrying multivalent (divalent, tetravalent) ligands. We show that in most cases the nanoparticles with multivalent ligands exhibit very minor or no advantage in cell surface targeting compared to nanoparticles functionalized with monovalent ligands with the same density of functional groups, as in both cases nanoparticles can interact with a receptor surface in a multivalent manner. We identify a few cases when using multivalent ligands in nanoparticle targeting can be beneficial, especially for a high binding energy of ligand–receptor interactions and large receptor densities. We demonstrate that for nanoparticles with longer tether length or larger core size, where the entropic loss for stretching tethers carrying ligands is significant, the possibility to deliver the same number of functional groups to a cell surface by using a smaller number of ligated tethers, as in the case of using multivalent ligands, becomes favorable. We also show that multivalent ligands can enhance the selectivity of nanoparticle targeting by increasing the nanoparticle affinity to cells with a high density of mobile receptors. The obtained results provide guidance for the experimental development of targeted nanoparticles with multivalent ligands for imaging and therapeutic applications.
Microarray comparative genomic hybridization and FISH studies of an unbalanced cryptic telomeric 2p deletion/16q duplication in a patient with mental retardation and behavioral problems.

We describe a 7-year-old patient with pervasive developmental disorder and behavioral problems who has a de novo cryptic unbalanced der(2)t(2;16)(p25.3;q24.3) chromosome resulting in deletion of distal 2p and duplication of distal 16q. These segmental aneusomies were detected by microarray comparative genomic hybridization analysis, as was a distal 17p13.3 duplication that was inherited from her father. FISH analysis using bacterial artificial chromosomes confirmed a deletion of approximately 1,700 kbp of DNA from 2pter (containing at least six complete genes or transcription units) and a duplication of ∼500 kbp from 16qter (including up to ten genes or transcription units). Several genes in these regions are plausible candidates for contributing to the patient's phenotype. © 2007 Wiley-Liss, Inc.
Effects of osmotic stress and growth stage on cellular pH and polyphosphate metabolism in Neurospora crassa as studied by 31P nuclear magnetic resonance spectroscopy

High-resolution 31P-NMR was employed to investigate the effects of growth stage and environmental osmolarity on changes of polyphosphate metabolism and intracellular pH in intact Neurospora crassa cells. Our study showed that changes of these parameters were growth-dependent. The ratio of polyphosphate to orthophosphate in vacuoles increased from 2.4 to 13.5 in N. crassa as cells grew from early log phase to stationary phase. Cytoplasmic pH and vacuolar pH changed, respectively, from 6.91 and 6.49 in early log phase cells to 7.25 and 6.84 in stationary phase cells. Hypoosmotic shock of N. crassa produced growth-dependent changes including: (i) a rapid hydrolysis of polyphosphate with a concomitant increase in the concentration of the cytoplasmic phosphate, (ii) an increase in cytoplasmic pH, and (iii) an increase in vacuolar pH. Early log phase cells produced the most dramatic response whereas the stationary phase cells appeared to be recalcitrant to the osmotic stress. Thus, 95% and 60% of polyphosphate in the early log phase and mid-log phase cells, respectively, disappeared in response to hypoosmotic shock, but little or no hydrolysis of polyphosphate occurred in stationary cells. The cytoplasmic pH and the vacuolar pH increased in response to hypoosmotic shock by 0.4 and 0.53 unit, respectively, in early log phase cells; and by 0.22 and 0.27 unit, respectively, in the mid-log phase cells. In contrast, hypoosmotic shock of the stationary phase cells did not cause any change in intracellular pH. The osmotic stress-induced polyphosphate hydrolysis and pH changes in early log and mid-log phase cells were reversible, suggesting that these changes were related environment osmolarity. Addition of polyamines or basic amino acids which are known to be sequestered in vacuoles did not effect polyphosphate metabolism.
Convective-diffusion-based fluorescence correlation spectroscopy for detection of a trace amount of E. coli in water

Fluorescence correlation spectroscopy (FCS) is adapted for a new procedure to detect trace amounts of Escherichia coli in water. The present concept is based on convective diffusion rather than Brownian diffusion and employs confocal microscopy as in traditional FCS. With this system it is possible to detect concentrations as small as 1.5 x 10(5) E. coli per milliliter (2.5 x 10(-16) M). This concentration corresponds to an approximately 1.0-nM level of Rhodamine 6G dyes. A detailed analysis of the optical system is presented, and further improvements for the procedure are discussed.
Nested abnormality theories

We propose a new approach to the use of circumscription for representing knowledge. Nested abnormality theories are similar to simple abnormality theories introduced by McCarthy, except that their axioms may have a nested structure, with each level corresponding to another application of the circumscription operator. The new style of applying circumscription sometimes leads to more economical and elegant formalizations. Mathematical properties of nested abnormality theories may be easier to investigate. These advantages are demonstrated by recasting several familiar applications of circumscription in the new format, including some examples of inheritance hierarchies, the domain closure assumption and causal minimization. Nested abnormality theories provide also a convenient representation for the explanation closure approach to the frame problem developed by Schubert.
Routine HIV testing hits the primary care clinic.

In September 2006, the Centers for Disease Control and Prevention (CDC) recommended screening all persons 13–64 years of age for human immunodeficiency virus (HIV) infection.1 Prior to this, screening recommendations were targeted to specific high-risk individuals and settings, and to all pregnant women. The rationale for expanded screening is that early diagnosis can reduce morbidity and mortality,2 and that persons who know their HIV status will modify their risk behaviors and reduce transmission.3 Furthermore, an estimated 25% of persons with HIV infection remained undetected with the existing screening strategy. Recently, the American College of Physicians and the HIV Medicine Association have come out in support of the CDC’s screening recommendation.4 Other organizations, such as the US Preventive Services Task Force, have not come out for or against the CDC recommendations, in part due to limited direct evidence on the benefits of screening.5 As new evidence emerges, key issues to consider for any screening program are the validity of the screening test, the feasibility of implementing the screening program, and the overall effectiveness in improving health outcomes. In this issue of JGIM, Myers and colleagues describe their experience of systematically implementing the CDC recommendations within six community care centers in the Southeastern US6. With programmatic support and some funding, the practices developed a systematic procedure to implement screening within the practice that did not directly involve the health care provider. In this study, over 16,000 persons were offered HIV testing, and of the 10,769 persons who accepted testing, 19 received a false-positive result, whereas 17 were confirmed positive, of whom 12 were successfully referred to care. Three patients did not have confirmatory testing. The findings from this study demonstrate key issues involving screening test validity and feasibility.
Self‐Assembly of Shape‐Persistent Hexagonal Macrocycles with Trimeric Bis(terpyridine)–FeII Connectivity

A novel family of bis(terpyridinyl) ligands was designed and constructed by facile Pd-catalyzed coupling reactions. Subsequent terpyridine–transition-metal complexation facilitated self-assembly resulting in a hexagonal, trimeric series of metallomacrocycles. An enhanced solubility of a macrocycle and its bis(terpyridine) precursor possessing elongated, alkyl-branched phenylacetylene spacers was achieved by the incorporation of dodecyloxy moieties. The characterization of the metallomacrocycles included 1H, 13C NMR, and UV spectroscopy and mass spectrometry, as well as electrochemistry.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Use of an ecologically based program for teaching motor skills in a naturalistic setting to individuals with disabilities.

The purpose of this action study was to apply an ecological program for teaching motor skills to individuals with disabilities in naturalistic settings. The program was developed based on an ecological survey. Participants were 22 individu als with disabilities, ages 7 to 26 years in the Fall of 1998 and 18 individuals with disabilities, ages 7 to 24 in the Winter of 1999. In each semester, a participant re ceived one or two 50-min, training session(s) per week for 10 weeks. The number of steps in a motor-activity task performed correctly by a participant was measured in the first and last sessions in each semester. The magnitude of increase in the motor performance by participants and answers to questions in a short survey by partic pants' parents were used to describe the group performance. Analysis showed group performance of targeted motor skills could be improved using this ecological program in this local learning lab for special physical education.
Accurate algorithms for nonuniform fast forward and inverse Fourier transforms and their applications

Regular fast Fourier transform (FFT) algorithms require uniformly sampled data. In many practical situations, however, the input data is nonuniform, and hence the regular FFT does not apply. To overcome this difficulty the authors have proposed an accurate algorithm for the nonuniform forward FFT (NUFFT) based on a new class of matrices, the regular Fourier matrices. For the nonuniform inverse FFT (NU-IFFT) algorithm, the conjugate-gradient method and the regular FFT algorithm are combined to speed up a matrix inversion. Numerical results show that these algorithms are more than one order of magnitude more accurate than existing algorithms.
Shiga Toxins Induce, Superinduce, and Stabilize a Variety of C-X-C Chemokine mRNAs in Intestinal Epithelial Cells, Resulting in Increased Chemokine Expression

Exposure of humans to Shiga toxins (Stxs) is a risk factor for hemolytic-uremic syndrome (HUS). Because Stx-producing Escherichia coli (STEC) is a noninvasive enteric pathogen, the extent to which Stxs can cross the host intestinal epithelium may affect the risk of developing HUS. We have previously shown that Stxs can induce and superinduce IL-8 mRNA and protein in intestinal epithelial cells (IECs) in vitro via a ribotoxic stress response. We used cytokine expression arrays to determine the effect of Stx1 on various C-X-C chemokine genes in IECs. We observed that Stx1 induces multiple C-X-C chemokines at the mRNA level, including interleukin-8 (IL-8), GRO-alpha, GRO-beta, GRO-gamma, and ENA-78. Like that of IL-8, GRO-alpha and ENA-78 mRNAs are both induced and superinduced by Stx1. Furthermore, Stx1 induces both IL-8 and GRO-alpha protein in a dose-response fashion, despite an overall inhibition in host cell protein synthesis. Stx1 treatment stabilizes both IL-8 and GRO-alpha mRNA. We conclude that Stxs are able to increase mRNA and protein levels of multiple C-X-C chemokines in IECs, with increased mRNA stability at least one mechanism involved. We hypothesize that ribotoxic stress is a pathway by which Stxs can alter host signal transduction in IECs, resulting in the production of multiple chemokine mRNAs, leading to increased expression of specific proteins. Taken together, these data suggest that exposing IECs to Stxs may stimulate a proinflammatory response, resulting in influx of acute inflammatory cells and thus contributing to the intestinal tissue damage seen in STEC infection.
Movie Images of Disability and War: Framing History and Political Ideology

For many decades, warfare and disability have been common in motion pictures. In this article, six Academy Award-winning movies on this subject are analyzed by synthesizing historical information, characteristics of specific disability conditions, and disability-related social issues. Each film's content is examined, with emphasis on how each may potentially influence viewer understanding of disability. Implications for special education practices are discussed.
Attachment and the investment model: Predictors of relationship commitment, maintenance, and persistence

This research examines adult attachment and the investment model. Study 1 tests anxiety and avoidance predicting romantic relationship commitment, mediated by satisfaction, alternatives, and investments. Additional studies added outcomes of relationship maintenance (Study 2) and persistence (Study 3). In all 3 studies, satisfaction, alternatives, and investments mediated the associations between anxiety and avoidance and relationship commitment. A direct effect of avoidance on commitment remained. The investment model variables mediated the effect of anxiety and avoidance on accommodation and willingness to sacrifice (Study 2) and relationship persistence (Study 3). Direct effects remained for avoidance on accommodation and anxiety on persistence. The mediated model was supported for men and women, proximal and long-distance relationships, and college student and community samples.
New Media and the `Pluralization of Life-Worlds' A Role for Information in Social Differentiation

This article asks whether, and in what ways, new media technologies contribute to variations in information resources and communication relations from place to place that may encourage social integration or differentiation. Current perspectives on differentiation theory are briefly discussed, and a model is presented which suggests how the generation, circulation and use of information in society create different social milieux or information environments. Recent studies of new media use are used to illustrate how ICTs might contribute to social differentiation.
Haptic interface for hands-on instruction in system dynamics and embedded control

A haptic interface serves as an ideal context and platform for teaching both system dynamics and embedded control. At The University of Michigan, a traditional undergraduate mechanical engineering course in systems dynamics and a new undergraduate electrical engineering course in embedded control systems have been equipped with instructional modules based on two new single-axis haptic interface devices. The iTouch motor is a low-budget, single axis, voice-coil based haptic device intended for teaching system dynamics fundamentals. Students gain hands-on experience by assembling these motors from scratch, performing experiments, and comparing actual to theoretically predicted dynamic response. A second device called "The Box" features higher torque output and robustness for the embedded control systems course. Both device designs are presented and contrasted and results following from their introduction into the curriculum are discussed. The uses of these devices to rapidly prototype various research projects and integrate undergraduate students into a research program are also briefly discussed.
Phenolic Amides Are Potent Inhibitors of De Novo Nucleotide Biosynthesis

An outstanding challenge toward efficient production of biofuels and value-added chemicals from plant biomass is the impact that lignocellulose-derived inhibitors have on microbial fermentations. Elucidating the mechanisms that underlie their toxicity is critical for developing strategies to overcome them. Here, using Escherichia coli as a model system, we investigated the metabolic effects and toxicity mechanisms of feruloyl amide and coumaroyl amide, the predominant phenolic compounds in ammonia-pretreated biomass hydrolysates. Using metabolomics, isotope tracers, and biochemical assays, we showed that these two phenolic amides act as potent and fast-acting inhibitors of purine and pyrimidine biosynthetic pathways. Feruloyl or coumaroyl amide exposure leads to (i) a rapid buildup of 5-phosphoribosyl-1-pyrophosphate (PRPP), a key precursor in nucleotide biosynthesis, (ii) a rapid decrease in the levels of pyrimidine biosynthetic intermediates, and (iii) a long-term generalized decrease in nucleotide and deoxynucleotide levels. Tracer experiments using 13C-labeled sugars and [15N]ammonia demonstrated that carbon and nitrogen fluxes into nucleotides and deoxynucleotides are inhibited by these phenolic amides. We found that these effects are mediated via direct inhibition of glutamine amidotransferases that participate in nucleotide biosynthetic pathways. In particular, feruloyl amide is a competitive inhibitor of glutamine PRPP amidotransferase (PurF), which catalyzes the first committed step in de novo purine biosynthesis. Finally, external nucleoside supplementation prevents phenolic amide-mediated growth inhibition by allowing nucleotide biosynthesis via salvage pathways. The results presented here will help in the development of strategies to overcome toxicity of phenolic compounds and facilitate engineering of more efficient microbial producers of biofuels and chemicals.
Metabolism of Monoepoxides of Methyl Linoleate: Bioactivation and Detoxification

Leukotoxin (ltx) and isoleukotoxin (iltx) methyl esters, are metabolites of methyl linoleic acid, an essential fatty acid. They have been associated with acute respiratory distress syndrome. The observed toxicity of ltx and iltx is, in fact, due to the metabolism of the epoxides to their corresponding diols by soluble epoxide hydrolase (sEH). Herein, we demonstrate that ltx/iltx are toxic in a time-dependent manner to human sEH expressing cells with a LT(50) of 10.6 +/- 0.8 h and that ltx and iltx have K(M) of 6.15 +/- 1.0 and 5. 17 +/- 0.56 microM, respectively, and V(max) of 2.67 +/- 0.04 and 1. 86 +/- 0.06 micromol/min/mg, respectively, which can be inhibited by sEH inhibitors. We show that four major metabolites of ltx/iltx are formed in our system, including ltx/iltx free acid, ltxd/iltxd, free acid, and phosphotidylcholine and phosphotidylethanolamine containing the carboxylic acid forms of both ltx/iltx and ltxd/iltxd, but that the only metabolite associated with toxicity is the carboxylic acid form of ltxd/iltxd, suggesting the involvement of cellular esterases. We demonstrate that a serine esterase inhibitor provides some protection from the toxicity of epoxy fatty esters to sEH expressing cells as do intercellular free sulfhydryls, but that this protection is not due to glutathione conjugation. With these data, we have proposed an extension of the metabolic pathway for ltx/iltx in eukaryotic cells.
Vasoocclusion in Sickle Cell Anemia Are Platelets Really Involved

After reviewing a peripheral blood smear from a patient with sickle cell anemia, one might predict that the clinical consequences of sickle hemoglobin would result simply from vascular obstruction by misshapen red cells. In fact, the pathophysiology of sickle cell disease is far more complex. Besides red cell adhesion to vascular endothelium, it includes the participation of leukocytes, blood coagulation proteins, and platelets. See page 1626 More than 25 years ago, Hebbel et al observed that sickle red cells adhere to cultured endothelial cells regardless of their state of oxygenation.1 It was found subsequently that sickle red cells, and in particular sickle reticulocytes, express a number of adhesion receptors including the integrin α4β1, the immunoglobulin receptor family member ICAM-4, basal cell adhesion molecule/Lutheran (BCAM/Lu), and CD36 that are normally present on red cell progenitors in the bone marrow, but disappear as the progenitors mature into circulating red cells.2,3 Their presence on sickle red cells may be a consequence of the accelerated rate of red cell production in sickle cell anemia and the absence of a functioning spleen. But why these proteins are more prevalent on sickle red cells than on red …
Grazing by mesozooplankton and microzooplankton on toxic and non-toxic strains of Microcystis in the Transquaking River, a tributary of Chesapeake Bay

The objective of this study was to assess the ability of laboratory-reared and natural communities of zooplankton to graze on toxic and non-toxic strains of Microcystis during bloom events in the Transquaking River, a tributary of Chesapeake Bay. The dynamics of toxic and non-toxic strains were documented via quantification of the microcystin synthetase gene (mcyD) and ribosomal RNA gene, 16S. During the 2-year field study, Microcystis blooms were comprised of >106 cell equivalents L-1 and the percentage of toxic strains ranged from 1 to 100%. The natural microzooplankton community was able to graze on both strains of Microcystis in two-thirds of experiments, with a slight preference for the non-toxic strains in most experiments. Cultured mesozooplankters (Daphnia pulex and Hyalella azteca) grazed at least one strain (toxic or non-toxic) of Microcystis in only one-third of experiments conducted. In contrast, the wild mesozooplankton community grazed at least one strain of Microcystis in every experiment with electivity indices showing a preference towards toxic strains in most experiments. This finding demonstrates that natural mesozooplankton were better grazers of both toxic and non-toxic strains of Microcystis than their cultured counterparts. Overall, both microzooplankton and mesozooplankton were capable of grazing toxic and non-toxic strains of Microcystis with similar success and at similar rates. As such, the ability to synthesize microcystin does not seem to offer toxic Microcystis populations a significant defense against grazing by co-occurring zooplankton communities.
Boundary value selection problem for image restoration using the reduced order model based Kalman filter

The reduced order-model Kalman filter (ROMKF) is a low order state-space model based Kalman filter. The motivation for introducing the ROM was the reduction in the amount of computation involved in a 2-D Kalman filter with full state-space model representation. Because of the way in which the state vector and the covariance are defined in the ROM, it is necessary to give careful consideration to the selection of the 2-D boundary conditions. A discussion is presented of such considerations, and it is shown, using both error indices and visual results, that proper boundary selection will significantly improve image restoration. >
Determining 802.11 link quality with passive measurements

Unlike a wired link, a wireless link changes according to the physical environment and the network traffic in the surrounding area. The link quality, capacity and reliability are dependent on the MAC layer parameters and the channel conditions. In this work, we present a new passive link quality measurement tool and study the effects of modulation rate changes, interflow and intraflow interferences on the wireless link. We observe the channel conditions (RSSI in both directions), retries, and various basic metrics to determine their usefulness in certain conditions. We found that RSSI is not a good metric for link quality since it does not correlate with the measured throughput. Other factors, such as modulation rate settings and the topology setups are also detailed in this paper.
Role of the Bombyx mori R2 element N-terminal domain in the target-primed reverse transcription (TPRT) reaction.

R2 is a site-specific non-long terminal repeat (non-LTR) retrotransposon encoding a single polypeptide with reverse transcriptase, DNA endonuclease and nucleic acid-binding domains. The current model of R2 retrotransposition involves an ordered series of cleavage and polymerization steps carried out by at least two R2 protein subunits, one bound upstream and one bound downstream of the integration site. The role in the retrotransposition reaction of two conserved DNA-binding motifs, a C2H2 zinc finger (ZF) and a Myb motif, located within the N-terminal domain of the protein are explored in this report. These motifs do not appear to play a role in RT or the ability of the protein to bind the R2 RNA transcript. Methylation and missing nucleoside interference-based DNA footprints using polypeptides to the N-terminal domain suggest the ZF and Myb motifs bind to regions −3 to −1 and +10 to +15 with reference to the insertion site. Mutations in these DNA sites or of the N-terminal protein domain blocked binding and the activity of the downstream subunit. Mutations of the protein domain also affected binding of the upstream subunit but not its function, suggesting the primary path to DNA target recognition by R2 involves both upstream and downstream subunits.
Zirconium tungstate reinforced cyanate ester composites with enhanced dimensional stability

Zirconium tungstate (ZrW2O8) is a unique ceramic material characterized by isotropic negative thermal expansion behavior over a wide temperature range. Incorporation of ZrW2O8 is expected to improve the dimensional stability of polymers by reducing the overall coefficient of thermal expansion (CTE). In this work, the thermal and dynamic mechanical properties of a bisphenol E cyanate ester reinforced with various loadings of ZrW2O8 are examined. Thermomechanical analysis indicates that the incorporation of ZrW2O8 results in a decrease in CTE at temperatures above and below the glass transition temperature (Tg) of the neat resin. The dynamic storage moduli of the composites reinforced with ZrW2O8 are found to increase with increasing filler loading. Furthermore, the various phase behaviors exhibited by ZrW2O8 are also examined by differential scanning calorimetry measurements.
The Turn Motif Is a Phosphorylation Switch That Regulates the Binding of Hsp70 to Protein Kinase C

Heat shock proteins play central roles in ensuring the correct folding and maturation of cellular proteins. Here we show that the heat shock protein Hsp70 has a novel role in prolonging the lifetime of activated protein kinase C. We identified Hsp70 in a screen for binding partners for the carboxyl terminus of protein kinase C. Co-immunoprecipitation experiments revealed that Hsp70 specifically binds the unphosphorylated turn motif (Thr(641) in protein kinase C beta II), one of three priming sites phosphorylated during the maturation of protein kinase C family members. The interaction of Hsp70 with protein kinase C can be abolished in vivo by co-expression of fusion proteins encoding the carboxyl terminus of protein kinase C or the carboxyl terminus of Hsp70. Pulse-chase experiments reveal that Hsp70 does not regulate the maturation of protein kinase C: the rate of processing by phosphorylation is the same in the presence or absence of disrupting constructs. Rather, Hsp70 prolongs the lifetime of mature protein kinase C; disruption of the interaction promotes the accumulation of matured and then dephosphorylated protein kinase C in the detergent-insoluble fraction of cells. Furthermore, studies with K562 cells reveal that disruption of the interaction with Hsp70 slows the protein kinase C beta II-mediated recovery of cells from PMA-induced growth arrest. Last, we show that other members of the AGC superfamily (Akt/protein kinase B and protein kinase A) also bind Hsp70 via their unphosphorylated turn motifs. Our data are consistent with a model in which Hsp70 binds the dephosphorylated carboxyl terminus of mature protein kinase C, thus stabilizing the protein and allowing re-phosphorylation of the enzyme. Disruption of this interaction prevents re-phosphorylation and targets the enzyme for down-regulation.
The Neural Coding of Stereoscopic Depth

Stereopsis is a process by which the visual system gauges the relative depth of objects in three-dimensional space by measuring minute positional differences between left and right images. According to the standard notion, this information is thought to be encoded in the primary visual cortex by differences in receptive field (RF) positions for the two eyes. We have developed in alternative model by which stereoscopic information is coded and transformed through a hierarchical chain of processing in the primary visual cortex. Initially, first-order neurons of the visual cortex, simple cells, encode depth information by a scheme based on differences in internal receptive field structure between left and right eyes. Further abstraction of information is achieved by a subset of second-order neurons, complex cells, that are well suited for the detection of depth information in a manner unaffected by positional variations of objects. We review physiological evidence from studies of the cat and monkey that are relevant to the proposed scheme.
Neuroblastoma: A Disease Requiring a Multitude of Imaging Studies*

Neuroblastoma stands out among pediatric solid tumors because of its relative frequency, intriguing natural history, prognostic biologic features, and therapeutic challenges. It is the most common extracranial pediatric solid tumor and the most common neoplasm in infancy; >90% of the approximately 600 cases diagnosed annually in the United States are in children 90% of cases. This embryonal neoplasm often encases vascular structures and, unlike most solid cancers, usually presents with substantial metastatic disease (bone, bone marrow, lymph nodes, liver; spread to lung or brain is rare). Hence, defining disease status requires CT (or MRI), bone scan, metaiodobenzylguanidine (MIBG) scan, bone marrow tests, and urine catecholamine measurements. The natural history is strikingly variable but is largely predictable from clinical and biologic features. The latter are critical for distinguishing low-risk (90% survival) from high-risk ( approximately 25%-30% survival) subsets, allowing identification of patients who, despite a favorable clinical profile (e.g., localized tumor), are likely to develop lethal metastatic disease, versus patients who have an ominous clinical profile (e.g., widespread disease) but are likely to survive, sometimes with little or no cytotoxic therapy.
Estimating DNA Repair by Sequential Evaluation of Head and Neck Tumor Radiation Sensitivity Using the Comet Assay

Background The alkaline comet assay is a microelectrophoretic technique for detecting single-strand DNA breaks, and may be used as an indirect measure of hypoxia by determining the radiation sensitivity of individual cells. Objective To assess the ability of the comet assay to estimate the rate of DNA repair after irradiation in patients with head and neck cancer. Methods The comet assay was used to evaluate DNA damage in fine-needle aspirates of lymph nodes containing metastatic squamous cell carcinoma in patients with head and neck cancer 1, 2, and 3 minutes after treatment with 500 rad (5 Gy) of irradiation. The amount of DNA damage (measured as the "tail moment" of the comet) is proportional to the number of DNA single-strand breaks after irradiation, which in turn depends on the oxygen concentration in each cell. Results The mean ± SD of the median tail moment of the 1-minute postirradiation comets was 29.4 ± 14.2 (n = 27). After 2 minutes, the mean median tail moment decreased to 25.4 ± 13.6 (n = 25), representing a mean decrease of 11.9% in those patients with both 1- and 2-minute comet assays. Assuming a linear rate of repair, this decrease in DNA damage corresponds to a repair half-life of 4.2 minutes. A 3-minute assay was also performed on samples from a smaller number of patients (n = 9), with a mean value not significantly different from that of the 2-minute assay of the samples from this group. Conclusions The comet assay is a promising tool for evaluating radiation sensitivity in individual cells. The rate of DNA repair early after irradiation is consistent with data in the literature.
Enhancing Mechanical Properties of Polymer Composites by Modification of Surface Acidity or Basicity of Fillers

The surface of a powdered glass has been treated to optimize its performance as a filler in polymer composites cast from solution. The aim has been to enhance acid-base interactions between the functional sites of polymers and the surface sites of the glass particles so as to insure complete coverage of the glass particles by adsorbed polymer molecules, and to thereby enhance both the adhesion and dispersion of the filler. The glass chosen for this study is a magnesium aluminum silicate of very low alkali metal content, and its surface sites have negligible basicity and only moderate acidity, as evidenced by weak adsorption of polymethylmethacrylate and negligible adsorption of chlorinated polyvinylchloride from solution in methylene chloride. Because of the negligible surface basicity of the filler, acidic polymers such as polyvinylbutyral and polyvinyl chloride are not adsorbed sufficiently to promote adhesion or dispersibility, and brittle or weak composites result. Surface treatments to enhance surface acidity or basicity of the glass particles were evaluated by electrophoresis in organic solvents, in which acidic particles had negative zeta-potentials and basic particles had positive zeta-potentials; untreated glass particles had zero zetapotentials. The most effective treatments were done with silane coupling agents; amino-silanes provided strong negative zeta-potentials and methacryloxy-silanes provided strong positive zeta-potentials. Angleresolved ESCA spectra showed that the adsorbed amino-silanes averaged about a monolayer in thickness and that half of the nitrogens bonded to the surface as ammonium groups and half were in the outer surface as basic amine groups; the carbonyl oxygens of the methacryloxy-silanes appeared to be bonded to the surface. Heavily-loaded polymer composites were made with the silane-treated and with untreated glass powders, using two acidic binders and a basic binder. The acidic binders were a polyvinylbutyral (PVB) binder cast from solution in a methanol-MIBK mixture, and a post-chlorinated polyvinylchloride (CPVC) binder cast from solution in a mixture of cyclohexane and tetrahydrofuran (THF): the glass transition temperature (Tg) for CPVC is about 140 C, but for PVB it is only about 35 C. The basic polymer (PEHM, polyethyl-hexylmethacrylate) has a Tg well below room temperature. Thus the extension to break in tensile tests was about 1% for CPVC, 10% for PVB, and 20 % for PEHM. About ten stress-strain Instron tests were made on each composite, and the composites with appreciable acid-base interactions between the matrix polymer and the surface sites of the treated glass fillers were in all cases much tougher than those without such acid-base interactions. The brittleness of the polyvinylbutyral composites filled with untreated glass powders was not observed at all on silane-treated glass powders.
An efficient partitioning algorithm of combinational CMOS circuits

This paper presents an efficient algorithm to partition combinational CMOS circuits for pseudoexhaustive testing. We present the effect of the partitioning algorithm on critical paths. Our objective is to reduce the delay penalty of test cell insertion for pseudoexhaustive testing. Pseudoexhaustive testing of a combinational circuit involves applying all possible input patterns to test all of its individual cones. Our testing ensures detection of all nonredundant combinational faults. We have developed an optimization process that can be used to find the optimal size of primary input cone (N) and fanout (F) values, to be used for partitioning a given circuit. In our work, the designer can choose between the fewest number of partitioning points and the least delay in critical path. ISCAS'85 benchmark circuits have been successfully partitioned, and when our results are compared to other partitioning methods, our algorithm makes fewer partitions.
Flow effects in the polymer cyclization reaction

We investigate the effect of shear and uniaxial extensional flows on the rate of the cyclization reaction in polymers. We find that for such an intramolecular diffusion-controlled reaction the flow always reduces the reaction rate, in contrast to the previously studied case of intermolecular reactions, where linear flows enhance the reaction rate.
Stationarity, homogeneity and isotropy of the electromagnetic field in the presence of random sources

Some of the consequences of stationarity, homogeneity and isotropy and some of the simplifications on the forms and relations among the second-order tensor potentials and correlation tensors in the presence of random sources are studied. General forms of the second-order correlation tensors are derived for a fluctuating electromagnetic field which is stationary, homogeneous and isotropic. For such a field it is shown that the seventy-six components of the correlation tensors of the fields, charges and currents depend only on two linearly independent scalar functions. If the field is not isotropic then the correlation tensors depend on ten linearly independent functions.
Scapular Malunion in a Vietnam War Veteran: Superior Medial Angle of the Scapula Impinging on the Clavicle

Case: Scapular malunion can be overlooked as a source of substantial upper-extremity pain and dysfunction and can generate unnecessary studies or treatments. We present the case of a Vietnam War veteran who sustained a projectile injury in the left shoulder and had persistent symptoms limiting his activity and quality of life for a number of years until surgical resection was performed. Conclusion: Scapular malunion should be considered in the differential diagnosis of a patient presenting with persistent upper-extremity pain and weakness following scapular fracture. Making the correct diagnosis based on the history, examination, and imaging will prevent unnecessary studies and invasive procedures.
Theory and Applications of Diffuse Reflectance Spectroscopy

At present there are at least 100 papers in the literature in which the diffuse reflectance method is used without question to obtain approximate absorption spectra of solids in the visible and near UV, or in which attempts are made to overcome the recognized limitations of the method, namely, that diffuse reflectance spectra are not always identical to transmission spectra. Some of the theories proposed to account for the difference will be discussed, those which purportedly permit one to compute absorption coefficients from diffuse reflectance data: the Kubelka-Munk dilution model, Johnson’s plate model, and the Melamed model.
Transitional Welfare Effects of Capital Income Tax Reform in a Small Open Economy

I study the transitional welfare effects of a budget neutral reform in a small open economy with overlapping generations and age-dependent mortality. The reform eliminates the capital income tax and replaces it with a consumption tax. I simulate the model for Chile and calculate lifetime welfare effects. I find that the reform generates welfare gains for all generations and on all dates. Furthermore, welfare gains are increasingly positive over time. At the time of the reform, generations born before the reform experience smaller welfare gains than the generation born on that date. At the same age, future generations experience significantly larger welfare gains than existing generations.
Specificity of basolateral organic cation transport in snake renal proximal tubules

We examined the specificity of basolateral organic cation transport in isolated snake (Thamnophis spp.) renal proximal tubules by determining the inhibitory effect of a series of n-tetraalkylammonium (n-TAA) compounds (n = 1-5) on the basolateral uptake of [3H]tetraethylammonium (TEA). The inhibitory potency increased with increasing alkyl chain length, with the apparent Michaelis constants for inhibition of TEA uptake ranging from 3.3 mM for tetramethylammonium (TMA) to 1.0 microM for tetrapentylammonium (TPeA). Thus the apparent affinity of the carrier for n-TAA compounds increases with their increasing hydrophobicity. Because previous data suggested that TEA transport across the basolateral membrane may be asymmetrical and that the exit step may be regulated differently from the entry step, we examined the kinetics of [3H]TEA efflux across the basolateral membrane, Efflux, like entry, occurred by a saturable process that could be described adequately by Michaelis-Menten kinetics. However, the concentration of TEA at one-half Jmax (Kt) for efflux (approximately 110 microM) was about six times the Kt for uptake (approximately 18 muM), indicating that the affinity of the carrier for TEA is greater in the uptake direction than in the efflux direction or that there are separate carriers with different affinities for uptake and efflux. In either case, this difference would favor movement of TEA taken up at the basolateral side across the cells and into the lumen over movement back into the peritubular fluid.
Exploring Measures of Team Knowledge

Team cognition is more than the aggregate cognition of team members. It is an emerging feature, worthy of study in its own right. In this paper we investigate potential metrics of team knowledge in the context of a broader exploratory study on measures of team knowledge, performance, and situation awareness. Team members assumed different roles in a three-person synthetic task in which they were presented with unique role-relevant information. Successful accomplishment of team objectives required team members to share information. The focus of this paper is on one of several measures collected which required judgments of pairwise relatedness ratings for mission-relevant terms. These data were submitted to Pathfinder network scaling and used to derive three metrics of team knowledge: knowledge accuracy, interpositional knowledge, and knowledge similarity. The metrics revealed different perspectives on team knowledge and were generally predictive of team performance and team situation awareness.