cssi/SciSciGPT-SciSciNet huggingface dataset:
Properties of a novel nitric oxide-stimulated ADP-ribosyltransferase

A novel ADP-ribosyltransferase is present in the cytosolic fraction of various cells. The kinetic behavior and physical properties of this enzyme's activity are clearly distinguished from other known cytosolic ADP-ribosyltransferases. Agents that release nitric oxide, such as sodium nitroprusside, greatly stimulated this activity, although this effect was dependent on the presence of intact thiol groups. Dithiothreitol, reduced glutathione, or cysteine was needed for activation of the enzyme, while N-ethylmaleimide inhibited enzyme activity. High concentrations of phosphate had a slight stimulatory effect, while high concentrations of sodium chloride and thiocyanate were inhibitory. ATP also inhibited this activity. This cytosolic ADP-ribosyltransferase is clearly distinguished from other known and characterized cytosolic transferases. Its activation by biologically active nitric oxide suggests an important role for this enzymatic activity.
Incidence of use of acid suppression medications in infants with oral clefting.

Abstract Objective: Less than 1% of the general pediatric population needs pharmacologic therapy for reflux symptoms; yet, the co-existence of gastroesophageal reflux disease (GERD) with oral clefting remains unclear. The purpose of this retrospective study was to appreciate the difference in the incidence of anti-GERD pharmacotherapy in a sample population of infants with oral clefting compared to the general pediatric population. Materials and Methods: One hundred ninety-six consecutive patients diagnosed with cleft lip only, cleft lip and palate, and isolated cleft palate were analyzed through clinical record review. Demographic and clinical information including but not limited to the type of oral cleft present at birth, reported signs and symptoms of GERD, and anti-GERD medications used were compiled for all subjects. Collected data were analyzed using descriptive statistics. Results: Sixty-four (33%) of 196 infants with oral clefts had documented signs and symptoms of GERD. Nine percent (18 of 196) ...
Efficient excitation of a mesospheric sodium laser guide star by intermediate-duration pulses

Calculations of backscatter emission of mesospheric sodium atoms in a laser guide star that is excited by pulses ranging from 30-ns to 0.9-μs duration are described. The efficient use of such pulses at saturating irradiance values is shown to require ~3 GHz of spectral broadening to provide access to the full absorption spectrum of the D2 line. The broadening is provided by frequency modulation. A set of density matrices was used to account for all 24 hyperfine states and inhomogeneous Doppler broadening. At the broadband (3-GHz) saturation irradiance of 4 W/cm2, both linearly and circularly polarized laser beams are shown to produce emission rates exceeding 60% of the maximum possible rate-equation rate for the 0.9-μs pulses. As expected, circular polarization produced more backscatter than did linear polarization, but the enhancement never exceeded 1/3 in the calculations that are reported. A brief estimate of state precession in the Earth’s magnetic field suggests that achieving even this enhancement will require that the time scale for optical pumping be held to less than 1 μs, which will require the use of irradiances greater than 0.7 W/cm2 and spectral coverage of the full 3-GHz hyperfine-plus-Doppler absorption profile, at least until most of the population is pumped out of the F = 1 ground states.
Calibration of solar cells by the reference cell method—The spectral mismatch problem

The calibration of solar cells by means of solar simulators and calibrated reference cells has always been faced with the problem of errors due to source spectral irradiance mismatch and cell spectral response mismatch. A general expression is derived in this paper to enable calculation of mismatch error. The information required to make this calculation is the relative spectra responses of the test and reference cells, and the relative spectral irradiance of the simulator (over the spectral range defined by cell response). The spectral irradiance of the solar standard is assumed given. Experimental results are presented.
Unnatural Inequalities: Social and Environmental Histories

This essay offers the perspective of a sympathetic outsider: a social historian who reads and admires environmental history. To the naive interloper, straying in from the methodological and topical cacophony of social history, environmental history initially seems refreshingly homogeneous and harmonious. But it does not take long to discover otherwise. As William Cronon has noted, "environmental history" is a broad umbrella covering at least three largely distinct sets of studies: first, of the place of specific human societies within particular but changing ecosystems; second, of varying cultural notions about humankind's relationship to nature; and third, of environmental politics and policy. Readers also should beware that my attempt to summarize the central tendencies of social history is a fool's errand; that field has become notorious for its extraordinary diversity, ranging from apolitical economic and demographic quantifiers to feminist theorists and Marxist labor historians. In both environmental and social history there are important exceptions to every general statement I will advance.' Like a tourist passing through a new land, my reactions probably reveal more about the complicated place from which I come rather than about the equally complex place that I have reached. Those reactions may be of some interest to environmental historians who fear that, in Cronon's words, there is "on the part of some social historians...a significant intellectual backlash going on against environmental history in general." At a panel during the 1994 convention of the Organization of American Historians, he and Richard White were troubled by a few negative responses to Cronon's Nature's Metropolis: Chicago and the Great West. Those attacks, however, derive almost exclusively from scholars better characterized as cultural geographers or economic historians. Rather than advance any sweeping dismissal of environmental history, most of those critics have focused on perceived flaws peculiar to that one book: the narration's occasional excursions into overt subjectivity and Cronon's preoccupation with relations of commerce, to the neglect of industrial production. Benign indifference, rather than hostility, best characterizes the response of social history to environmental history. It is revealing that, alone among the major Ameri
The national sheet metal worker asbestos disease screening program: Radiologic findings

This report presents data gathered from a series of asbestos disease screening examinations of 9,605 United States sheet metal workers who were first employed in the trade at least 20 years before the examination. The overall prevalence of asbestos-related radiographic changes was 31.1%: 18.8% had pleural abnormalities alone, 6.6% had parenchymal abnormalities (International Labour Office (ILO) score of 1/0 or higher) alone, and 5.7% had both. Among those with 40 years or more since entering the trade, 41.5% had radiographic signs of asbestos-related disease, 24.2% pleural alone, 7.7% parenchymal alone, and 9.6% both pleural and parenchymal abnormalities. After controlling for several surrogates for asbestos exposure level, cigarette smoking was found to increase risk of parenchymal, and more modestly, pleural abnormalities. Each pack-year was associated with a 1% increased prevalence odds ratios for parenchymal abnormalities (ILO category 1 compared to category 0), and 0.4% increased prevalence odds ratios for pleural abnormalities. A history of shipyard employment also produced significantly increased prevalence odds ratios for each radiographic category. More that 90% of chest radiographs were classified by A or B readers; after adjustment for other risk factors, A readers were more likely to report parenchymal abnormalities of category 1, but not more likely to report category 2 or pleural abnormalities, than B readers.
Strontium induces murine keratinocyte differentiation in vitro in the presence of serum and calcium

Primary mouse keratinocytes in culture are induced to terminally differentiate by increasing extracellular Ca2+ concentrations (CaO) from 0.05 mM to ≥ 0.1 mM. The addition of Sr2+ (≥ 2.5 mM) to medium containing 0.05 mM Ca2+ induces focal stratification and terminal differentiation, which are similar to that found after increasing the CaO to 0.12 mM. Sr2+ in 0.05 mM Ca2+ medium induces the expression of the differentiation-specific keratins, keratin 1 (K1), keratin 10 (K10), and the granular cell marker, filaggrin, as determined by both immunoblotting and immunofluorescence. Sr2+ induces the expression of those differentiation markers in a dose dependent manner, with an optimal concentration of 5 mM. In the absence of Ca2+ in the medium, the Sr2+ effects are reduced, and Sr2+ is ineffective when both Ca2+ and serum are deleted from the medium. Sr2+ treatment increases the ratio of fluorescence intensity of the intracellular Ca2+ sensitive probe, fura-2, indicating an associated rise in the level of intracellular free Ca2+ and/or Sr2+. At doses sufficient to induce differentiation, Sr2+ also increases the level of inositol phosphates in primary keratinocytes within 30 min. The uptake curves of 85Sr2+ by primary keratinocytes are similar to those of 45Ca2+. At low concentrations, the initial uptake of both 45Ca2+ and 85Sr2+ reaches a plateau within 1 hr; at higher concentrations, the uptake of both 45Ca2+ and 85Sr2+ increases continuously for 12 hr. In keratinocytes pre-equilibrated with 45Ca2+ in 0.05 mM Ca2+ medium, Sr2+ causes an increase of 45Ca2+ uptake, which is dependent on the presence of serum. These results suggest that Sr2+ utilizes the same signalling pathway as Ca2+ to induce keratinocyte terminal differentiation and that Ca2+ may be required to exert these effects. © 1993 Wiley-Liss, Inc.
Work through the web: a typology of web 2.0 services

To better understand how publicly available online services (PAOSs) are used by knowledge workers on the web, we devised and tested a classification scheme for Web 2.0 services. This classification scheme focuses on genres of services and types of interactions associated with PAOSs. Our experiment, which involved a double-coded assessment of 238 unique sites, demonstrates that our definition of Web 2.0 and our defined genres and associated user interaction types are recognizable. In addition, this study suggests that genres of services can be a valuable instrument in the analysis, discussion, and design of sites used by knowledge workers.
Comparison of the electric properties of single-crystal and polycrystalline diamond by hall effect and capacitance-voltage measurements

Abstract The transport properties of type IIb (naturally B-doped), single-crystal diamond were investigated by differential capacitance-voltage ( C - V ) measurements, Hall effect measurements and resistivity measurements. The results for the Hall effect and resistivity measurements on single-crystal samples were compared with similar measurements on polycrystalline samples grown by microwave-assisted chemical vapor deposition. The C - V and Hall effect measurements on single crystal, type IIb diamond samples showed consistent results. Temperature-dependent resistivity measurements verified an activation energy of 0.36 eV, while room temperature Hall effect measurements on a (100)-oriented, type IIb single crystal indicated that the active carrier concentration was 2.1 × 10 13 cm −3 . This result was consistent with total B concentrations measured by both C - V and secondary ion mass spectroscopy (SIMS). The transport properties for polycrystalline samples were not as good as those for single-crystal samples. At room temperature, the mobilities were 3 and 10 cm 2 V −1 s −1 for two in situ doped polycrystalline thin films, as compared with 325 cm 2 V −1 s −1 for the single-crystal sample. For one in situ doped sample, the activation energy was measured to be 0.05 eV and the room temperature carrier concentration was 1.8 × 10 16 cm −3 , while SIMS indicated that the total atomic B concentration was 5 × 10 18 cm −3 . The relatively low carrier concentrations measured in the polycrystalline samples may be indicative of a high level of compensation (about 65%) or trapping of charge at the grain boundaries, leading to a depletion of carriers in the crystallites.
The structure and Lewis acidity of some triorganotin carboxylates

A series of tributyltin carboxylates and one triphenyltin carboxylate were prepared by reaction of the tin oxide with the appropriate carboxylic acid. The tin-119 chemical shift of each compound in chloroform and, for the solid carboxylates, in the solid state was determined. A comparison of the solution (109–157 ppm) and solid state shifts (−53 to +45 ppm) indicates that the compounds exist primarily as monomeric 4-coordinate species in solution and as 5-coordinate, presumably polymeric species in the solid state. The Lewis acidity of the compounds toward triethylphosphine oxide (TEPO) was determined by recording the 31P chemical shift in a mixture of the carboxylate and TEPO in toluene as a function of concentration. Predominant 1 : 1 adduct formation was observed with equilibrium constants ranging from 5 to 320. The magnitude of the constant can be explained by the electronic effects of the substituents surrounding the tin.
Bioactivity of [6R]-5-formyltetrahydrofolate, an unusual isomer, in humans and Enterococcus hirae, and cytochrome c oxidation of 10-formytetrahydrofolate to 10-formyldihydrofolate.

The bio-inactive C-6 isomer, [6R]-5-formyl-tetrahydrofolate (5-HCO-H(4)F), is not found in Nature. An oral dose of 13.5 micromol of [6R]-5-HCO-H(4)F in humans results in the appearance of the naturally occurring [6S]-5-methyl-tetrahydrofolate and relatively large amounts of other bioactive folates in plasma. The removal of the asymmetry at C-6 could account for these results. Two oxidized cytochrome c [cyt c (Fe3+)] molecules oxidize one 10-formyl-tetrahydrofolate (10-HCO-H(4)F) with second-order kinetics and a rate constant of 1.3 x 10(4) M(-1) x s(-1). The folate product of this oxidation reaction is 10-formyl-dihydrofolate (10-HCO-H(2)F), which has no C-6 asymmetric centre and is therefore bioactive. The folate-requiring bacterium, Enterococcus hirae, does not normally biosynthesize cytochromes but does so when given an exogenous source of haem (e.g. haemin). E. hirae grown in haemin-supplemented media for 3 days utilizes both [6R]- and [6S]-5-HCO-H(4)F in contrast to that grown in control medium, which utilizes only the [6S] isomer. Since known chemical reactions form 10-HCO-H(4)F from 5-HCO-H(4)F, the unusually large rate constant for the oxidation of 10-HCO-H(4)F by cyt c (Fe3+) may account for the unexpected bioactivity of [6R]-5-HCO-H(4)F in humans and in E. hirae grown in haemin-containing media. We used an unnatural C-6 folate isomer as a tool to reveal the possible in vivo oxidation of 10-HCO-H(4)F to 10-HCO-H(2)F; however, nothing precludes this oxidation from occurring in vivo with the natural C-6 isomer.
A Computer-Controlled Whole-Body Inhalation Exposure System for the Oil Dispersant COREXIT EC9500A

An automated whole-body inhalation exposure system capable of exposing 12 individually housed rats was designed to examine the potential adverse health effects of the oil dispersant COREXIT EC9500A, used extensively during the Deepwater Horizon oil spill. A computer-controlled syringe pump injected the COREXIT EC9500A into an atomizer where droplets and vapor were formed and mixed with diluent air. The aerosolized COREXIT EC9500A was passed into a customized exposure chamber where a calibrated light-scattering instrument estimated the real-time particle mass concentration of the aerosol in the chamber. Software feedback loops controlled the chamber aerosol concentration and pressure throughout each exposure. The particle size distribution of the dispersant aerosol was measured and shown to have a count median aerodynamic diameter of 285 nm with a geometric standard deviation of 1.7. The total chamber concentration (particulate + vapor) was determined using a modification of the acidified methylene blue sp...
The brain renin angiotensin system: a re-evaluation.

Publisher Summary The substance of renal origin, renin is a proteolytic enzyme of molecular weight about 40,000 localized in the juxtaglomerular cells of the kidney. This substance is secreted in increased amounts following systemic hypotension, increased activity of the renal sympathetic nerves, and a reduction in the sodium load to the distal tubule of the kidney. It is important to evaluate the information supporting the existence of a brain renin/angiotensin system. The presence of such a system in the brain acting independently of the peripheral renin/angiotensin system would have important implications in many control systems. The actions that are elicited by the central administration of angiotensin can also be elicited by systemic injection or by procedures that raise the endogenous systemic production of angiotensin. This fact, together with the equivocal evidence for brain-renin activity, and the presence of angiotensin II in brain put the existence of the brain renin–angiotensin system in doubt. Angiotensin II is a potent stimulator of aldosterone secretion and is intimately involved in the control of sodium excretion. Angiotensin increases sympathetic activity in the periphery by a combination of facilitation of adrenergic transmitter release and increasing the sensitivity of smooth muscle to transmitter. This chapter discusses the actions that angiotensin II has on the central nervous system.
Determinants of Moloney Murine Leukemia Virus Gag-Pol and Genomic RNA Proportions

ABSTRACT The Moloney murine leukemia virus (MoMLV) ribonucleoprotein complex is composed of an approximately 20:1 mixture of Gag and Gag-Pol polyproteins plus a single genomic RNA (gRNA) dimer. The mechanisms that regulate these proportions are unknown. Here, we examined whether virion proportions of Gag, Gag-Pol, and gRNA were determined by sampling (that is, if they reflected expression ratios or intracellular concentrations) or more specific recruitment. To this end, MoMLV Gag, Gag-Pol, and gRNA were expressed separately or together in various ratios. Varying the expression ratios of Gag and Gag-Pol revealed that Gag-Pol incorporation was stochastic and that the conserved 20:1 Gag/Gag-Pol ratio coincided with maximal particle production. When skewed expression ratios resulted in excess Gag-Pol, the released virions maintained the intracellular Gag/Gag-Pol ratios and the infectivity per virion was largely maintained, but virion production decreased sharply with high levels of Gag-Pol. The determinants of gRNA proportions were addressed by manipulating the amounts and contexts of functional nucleocapsid (NC) and the ratios of Gag to gRNA. The results showed that the NC domain of either Gag or Gag-Pol could provide gRNA packaging functions equally well. Unlike Gag-Pol, gRNA incorporation was saturable. An upper limit of gRNA incorporation was observed, and particle production was not disrupted by excess gRNA expression. These results indicate that the determinants of Gag/Gag-Pol proportions differ from those for Gag/gRNA. On the basis of the assumption that MoMLV evolved to produce virion components in optimal proportions, these data provide a means of estimating the proportion of unspliced MoMLV RNA that serves as genomic RNA. IMPORTANCE Viruses assemble their progeny from within the cells that they parasitize, where they must sort through a rich milieu of host proteins and nucleic acids to gather together their own building blocks, which are also proteins and nucleic acids. The research described here addresses whether or not the proportions of viral proteins and nucleic acids that are brought together to form a retroviral particle are determined by random sampling from the cell—and thus dictated by the components9 availabilities within the cell—or if the amounts of each molecule are specified by the virus replication process. The results indicated that protein components of the murine retrovirus studied here are recruited by chance but that a specific counting mechanism defines the amount of nucleic acid incorporated into each progeny virion.
Evidence that tactile stimulation inhibits nociceptive sensations produced by innocuous contact cooling.

Abstract It was recently shown that stinging, pricking or burning is reliably perceived by some individuals when the skin is cooled to temperatures as mild as 25–30 °C. These seemingly paradoxical sensations, which have been termed innocuous-cold nociception (ICN), were significant only when cooling was produced by a thermode resting statically on the skin (static contact); touching an already cooled thermode to the skin (dynamic contact) produced reports of only coolness and cold. The present study investigated the hypothesis that ICN is inhibited by tactile stimulation produced when a thermode contacts the skin. Experiment 1 pitted the tactile hypothesis against an alternative explanation that inhibition results from higher rates of skin cooling during dynamic contact. ICN was measured at three different cooling rates (−1.0, −2.5, −5.0 °C/s) when the thermode was resting on the skin or was touched to the skin at the moment cooling began. The results supported the tactile hypothesis: faster cooling rates during static contact led to stronger rather than weaker nociceptive sensations, and ICN was suppressed even when dynamic contact was coincident with the onset of cooling, and thus could not affect cooling rate. Experiment 2 confirmed the latter result and showed that suppression was greatest at 28 °C, less at 24 °C, and not significant at 18 °C. We conclude that dynamic tactile stimulation produced by contact with a surface inhibits the nociceptive component of innocuous but not noxious cooling. The implications of this conclusion for the role of cold perception in behavioral thermoregulation versus haptic perception, and for theories of cold perception in general, are discussed.
Compact Raman Spectrometers: Data Handling Methods

Measurements have been made on a compact dispersive Raman spectrometer of the type often proposed for on-line measurements. Quantitative use of the details of spectra that are produced by this system require different data treatments than those which have been described for longer-focal-length instruments. The data sets are sparsely sampled, and they cover a wide spectral window. Owing to sparse sampling, spectra as recorded have the appearance of piecewise linear approximations. It is necessary to interpolate additional data points in order to observe details of peaks, such as exact positions of maxima. With wider spectral windows, procedures for calibration of the wavenumber axis which have been previously described do not meet our performance criterion: an accuracy of 0.1 cm-1 or better. A model that involves a fifth-order polynomial is needed. On the basis of the performance of this model, atomic lines which give satisfactory results when used as wavenumber references have been identified. Details of a self-modeling procedure for removal of broad-band spectral interferences are described, and its performance is demonstrated.
Monitoring changes of 3D building elements from unordered photo collections

This paper proposes an automated method for monitoring changes of 3D building elements using unordered photo collections as well as Building Information Models (BIM) that pertain information about geometry and relationships of elements. This task is particularly challenging as existing construction photographs are taken under different lighting and viewpoint conditions, are uncalibrated and extremely cluttered by equipment and people. Given a set of these images, our system first uses structure-from-motion, multi-view stereo, and voxel coloring algorithms to calibrate cameras, reconstruct the construction scene, quantize the scene into voxels and traverse and label the voxels for observed occupancy. The BIM is subsequently fused into the observed scene by a registration-step and voxels are traversed and labeled for expected visibility. Next, a machine learning scheme built upon a Bayesian model is proposed that automatically detects and tracks building elements in presence of occlusions. Finally, the system enables the expected and reconstructed elements to be explored with an interactive, image-based 3D viewer where construction progress deviations are automatically color-coded over the BIM. We present promising results on several challenging construction photo collections under different lighting conditions and sever occlusions.
Reactions of hydrogen and tritium atoms with carbon at 77°K☆

Abstract Hydrogen containing tritium was atomized at a hot tungsten filament, and the atoms were reacted with carbon (graphite, lamp black and diamond) at 77°K. At pressures low enough to allow a collision-free path for the hydrogen atoms between the filament and the surface of the carbon, CH4, C2H6, C3H8, iso-C4H10, n-C4H10 were produced and an unidentified higher molecular weight compound was extracted by benzene from graphite. Only CH4 and C2H6 were formed with hydrogen atoms moderated to 77°K by an inert helium atmosphere. Graphite was more reactive than diamond or lamp black. The distribution of products was found to vary with filament temperature, hydrogen pressure and length of reaction time. A sequence of consecutive reactions is proposed as the mechanism for the formation of the hydrocarbons.
Renin Inhibition in Hypertension

Fifty years ago, investigators identified renin inhibition as the preferred pharmacologic approach to blockade of the renin–angiotensin system. Renin is a monospecific enzyme that catalyzes the rate-limiting step in the synthesis of angiotensin II. Amplified enzymatic activity and additional physiological effects occur when renin and pro-renin bind to the (pro)renin receptor. Until very recently, development of clinically effective renin inhibitors remained elusive. Molecular modeling was used to develop aliskiren, a potent, low-molecular-weight, nonpeptide, direct renin inhibitor with sufficient bioavailability to produce sustained suppression of plasma renin activity after oral administration. In patients with hypertension, aliskiren produces dose-dependent blood pressure (BP) reduction and 24-h BP control up to a dose of approximately 300 mg once daily; at these doses, aliskiren shows placebo-like tolerability. Its antihypertensive potency is approximately equivalent to that of angiotensin receptor blockers, angiotensin-converting enzyme inhibitors, and diuretics. After abrupt withdrawal, persistent BP reduction and prolonged suppression of plasma renin activity is observed. When combined with diuretics, fully additive BP reduction is seen. When given with an angiotensin receptor blocker, aliskiren produces significant additional BP reduction indicative of complimentary pharmacology and more complete renin–angiotensin system blockade. Clinical trials are currently underway assessing the effects of aliskiren combined with an angiotensin receptor blocker on intermediate markers of end organ damage, and long-term end point trials are planned. The results of these studies will ultimately determine the place of renin inhibition and aliskiren in the treatment of hypertension and related cardiovascular disorders. The effect of aliskiren on receptor-bound renin and pro-renin is the subject of active investigation.
THE MEDIATOR OF CELLULAR IMMUNITY : VII. LOCALIZATION OF SENSITIZED LYMPHOCYTES IN INFLAMMATORY EXUDATES

Peritoneal exudates induced in rats infected with Listeria monocytogenes contain sensitized lymphocytes which can protect normal recipients against a Listeria challenge. The protective cells arise in lymphoid tissue remote from the peritoneal cavity. Those formed in the caudal lymph nodes of subcutaneously infected rats are delivered to the thoracic duct and hence to the blood from where they are drawn into exudates. Immunoblasts are the most immature members of this protective cell population and they alone among the cells in central lymph localize in exudates induced by killed bacteria. They do so in substantial numbers, but only during the early postinduction period. The "homing" of immunoblasts to inflammatory foci seems to be determined by a general property of the cells rather than their immunological commitment; however, the intense inflammation induced by organisms to which an animal has been specifically sensitized is accompanied by an exuberant influx of immunoblasts into lesions. Sensitized lymphocytes that extravasate in the inflamed peritoneal may generate more of their own kind, but some give rise to small lymphocytes. The latter also have protective properties and, with time, comprise an increasing portion of the protective cell population. The results imply that the tissue disposition of sensitized lymphocytes in the body is determined by a complementary relationship between blood-borne immunoblasts and vascular endothelium in inflamed tissue. The results also provide a plausible explanation for the concentration of sensitized lymphocytes at sites of microbial implantation where they alone would be expected to collaborate with monocyte-derived macrophages in the control of infection.
Interaction of ligands with pig heart citrate synthase: conformational changes and catalysis.

The fluorescence polarization of 8-hydroxypyrene (1,3,6)trisulfonate (HPT) increases upon interaction with pig heart citrate synthase. Titration of HPT with increasing concentrations of citrate synthase exhibits a hyperbolic saturation behavior, from which the dissociation constant of the enzyme-HPT complex (3.64 +/- 0.3 microM) was determined. The enzyme-HPT interaction is competitively inhibited by oxaloacetate (but not affected by acetyl CoA) with a Ki of 4.3 +/- 1.8 microM. This value is similar to the dissociation constant (Kd = 4.5 +/- 1.6 microM) for the enzyme-oxalocetate complex (determined in the absence of any effector ligand), as well as to the Km for oxaloacetate (3.9 +/- 0.7 microM) in a steady-state citrate synthase catalyzed reaction at a saturating concentration of acetyl CoA. However, the dissociation constant for the citrate synthase-oxaloacetate complex determined by the urea denaturation method is at least 25-fold lower than those determined by the other methods. This suggests an effector role of urea in strengthening the enzyme-oxaloacetate interaction. At low nondenaturing concentrations, urea inhibits the citrate synthase catalyzed reaction in an uncompetitive manner with respect to oxaloacetate, i.e., the Km for oxaloacetate decreases with an increase in urea concentration. This further suggests that urea stabilizes the interaction between citrate synthase and oxaloacetate. The effect of urea is specific for the substrate oxaloacetate, and not for the substrate analogue, HPT, although both these ligands bind citrate synthase with equal affinities, and protect the enzyme against thermal denaturation with equal magnitudes. The results presented herein are discussed in the light of known conformational states of the enzyme.
Monitoring anchoring energy in LC-based sensors

Liquid crystal (LC) based sensors have been investigated over the past decades in an effort to develop low cost, portable, field-deployable, highly selective chemical and biological sensors. Due to the collective behavior and the highly anisotropic properties of liquid crystal molecules, detection of very low levels (ppbs) of chemical and biological agents is possible. However, present LC sensors rely on a threshold concentration of a targeted analyte to cause a surface driven molecular reorientation of the LC molecules. In this paper, we present techniques using capacitive transduction to monitor anchoring energy that improve sensitivity of LC based sensors.
Muslim Persecution of Heretics during the Marwānid Period (64–132/684–750)

This article traces the emergence of a systematic approach to combating heresy during the Umayyad period. It argues that the Umayyads sought to silence religious dissent by labelling it as heresy and that the doctrinal boundaries of “orthodoxy” narrowed as the Umayyad period progressed. The article also asserts that Umayyad efforts to impose their vision of orthodoxy were an important precedent for the miḣna under the ʿAbbāsids.
Equity trading volume and volatility: Latent information arrivals and common long-run dependencies

This article examines the behavior of equity trading volume and volatility for the individual firms composing the Standard & Poor's 100 composite index. Using multivariate spectral methods, we find that fractionally integrated processes best describe the long-run temporal dependencies in both series. Consistent with a stylized mixture-of-distributions hypothesis model in which the aggregate “news”-arrival process possesses long-memory characteristics, the long-run hyperbolic decay rates appear to be common across each volume-volatility pair.
Enhancement of norepinephrine release from rat brain synaptosomes by alpha cyano pyrethroids

Abstract Using a continuous perfusion system, synaptosomes prepared from rat brain readily took up l -[7,8-3H]norepinephrine and released it in a calcium-dependent, potassium-stimulated manner. Of the insecticides tested, only pyrethroids which contained an alpha cyano grouping as part of their phenoxybenzyl alcohol moiety (i.e., deltamethrin, cypermethrin, and fenvalerate) enhanced calcium-dependent, potassium-stimulated release of [3H]norepinephrine. Non-cyano-pyrethroids (i.e., allethrin, des-cyano deltamethrin, des-cyano cypermethrin, and des-cyano fenvalerate) were greatly reduced in their ability to enhance [3H]norepinephrine release. None of the pyrethroids tested had any effect on [3H]norepinephrine uptake at concentrations at or below 10−5 M. None of the pyrethroids tested at concentrations up to 10−5 M had any effect on [3H]norepinephrine release from nondepolarized synaptosomes. The ED50 dose of deltamethrin which resulted in half-maximal-enhanced [3H]norepinephrine release (i.e., 2.9 × 10−9 M) correlated well with the ED50 dose of deltamethrin which resulted in half-maximal-enhanced 45Ca uptake (i.e., 2.4 × 10−9 M). Parathion and the noninsecticidal DDT analog, DDE, had no effect on [3H]norepinephrine uptake or release. DDT was found to be the most potent inhibitor of [3H]norepinephrine uptake.
Recovery of bone strength in young pigs from an induced short-term dietary calcium deficit followed by a calcium replete diet

This study investigated whether the deficits in bone strength of pre-pubertal pigs, induced by short-term deficits in dietary calcium can be recovered if followed by a calcium-fortified diet. Young pigs were divided into two groups based on diet: a marginal Ca diet (70% of established Ca requirements) or an excess Ca diet (150% of established Ca requirements) for 4 weeks. Each group was then randomly sub-divided into two groups and fed diets with either marginal or excess dietary Ca for 6 weeks in a cross-over design, resulting in four treatment groups: H150-H150, H150-L70, L70-H150, and L70-L70. Animals were DXA scanned at 2-week intervals during the 10-week period to obtain whole body bone mineral content (BMC) and density (BMD). After animals were euthanized, right femurs were collected for this study. Traits such as bone mineral density, mass, volume, area moment of inertia (MI) and the section modulus (SM) were computed from computed tomography (CT) data and failure load was measured from four-point bending tests. DXA results showed significant reduction in BMC (61.6%) and BMD (37.5%) in the (L70-L70) group compared to the (H150-H150) group. DXA results additionally showed that deficiencies induced by the 4-week marginal Ca diet in the (L70-H150) group were not recovered with a subsequent excess Ca diet. While mechanical test results also showed significant reduction (75%) in strength in the L70-L70 group, compared to the H150-H150 group, they revealed no differences between the failure loads of the (L70-H150) group and the (H150-H150) group. Similar results were also found for bone mineral mass and volume, indicating that recovery from a short-term dietary Ca deficiency is possible at the pre-pubertal stage. Furthermore, bone mineral content and bone volume calculated from CT data correlated highly with failure load (R(2)=0.78 and 0.84, respectively), while density, MI and SM only showed weak-to-moderate correlations (R(2)=0.40-0.56), implying that bone mineral mass and volume calculated from CT data are good non-invasive surrogates for strength of growing bones.
Virus-like particles in Basidiobolus species

Transmission electron microscopy of ultrathin sections of hyphal cells of Basidiobolus haptosporus and B. ranarum revealed the presence of particulate inclusions consistent in morphology with that described in certain other fungi as virus-like particles. Two types of particles were observed which differed in substructure and distribution within the host cytoplasm. Relative numbers of these particles were never great, and their presence in the host was not associated with any demonstrable cytopathological changes detectable at the ultrastructural level. We believe this report to be the first description of an association of virus-like particles with fungi of the Entomophthoraceae.
New antiviral agents for the treatment of hepatitis C: ABT-450

Introduction: Hepatitis C virus (HCV) therapy continues to evolve rapidly. ABT-450 is a novel potent inhibitor of the non-structural 3/4A protease that has been studied in combination with several agents, allowing shorter duration of therapy and interferon-free/ribavirin-free all-oral regimens. Preliminary data from studies evaluating these new regimens are impressive with sustained virological response (SVR) rates of 88 – 100% after 12 weeks of therapy in patients with previously untreated HCV genotype 1 infection. SVR rates in treatment-experienced patients are also encouraging. Areas covered: Efficacy and tolerability of antiviral regimens containing ABT-450 boosted with ritonavir (ABT-450/r). Results from published studies and abstracts from recent meetings are presented. Expert opinion: Newer direct-acting antiviral agents such as ABT-450 promise effective and durable suppression of HCV with interferon/ribavirin-free all-oral regimens. This agent also allows for shorter duration of treatment and has ...
Paleomagnetic data from the margin of a hypabyssal andesite in the western aleutians, Alaska

Abstract Paleomagnetic data used to establish the thermal nature of an andesite-sediment contact on Shemya Island are reported. The variations in the magnetic properties of the andesite appear to result from systematic increases in oxidation effects toward the contact.
Latency of Marek's Disease Virus (MDV) in a Reticuloendotheliosis Virus–Transformed T-Cell Line. II: Expression of the Latent MDV Genome

Abstract Marek's disease virus (MDV) is an alphaherpesvirus of chickens that causes the paralysis and rapid lymphoma formation known as Marek's disease. MDV establishes latent infection in activated CD4+ T-cells, and these cells are also the target for transformation. MDV latency has been studied using MDV lymphoma-derived cell lines and T-cells isolated from infected chickens. Each of these models has limitations because MDV-transformed cell lines require the use of oncogenic viruses; conversely, pools of latently infected cells are in relatively low abundance and invariably contain cells undergoing reactivation to lytic infection. In this study we have examined the spontaneous and induced expression of the MDV genome, the effect of genome uptake on cellular proliferation and apoptosis resistance, and differences in cellular surface antigen expression associated with MDV genome uptake in a reticuloendotheliosis virus (REV)–transformed T-cell model. We report that the MDV genome is highly transcribed duri...
Extracting 1/f noise coefficients for BJT's

We present a method for extracting the BJT SPICE noise model parameters AF and KF based on a general analysis of the small-signal equivalent circuit and the role of the internal BJT noise sources. The analysis is valid even for transistors with poor current gain and large base-collector conductance, for which the output noise characteristics may not be dominated by base flicker and shot noise. The method consists of interpreting the measured 1/f corner frequency versus DC current data in terms of the BJT's internal noisy small signal equivalent circuit. Measured data is presented for an implanted-emitter and two polysilicon-emitter bipolar technologies. >
Differentiation of Benign and Malignant Pathology in the Head and Neck Using 3T Apparent Diffusion Coefficient Values: Early Experience

BACKGROUND AND PURPOSE: The purpose of this work was to study differences in apparent diffusion coefficient (ADC) values between benign and malignant head and neck lesions at 3T field strength imaging. MATERIALS AND METHODS: Our study population in this retrospective study was derived from the patient population who had undergone routine neck 3T MR imaging (for clinical indications) from December 2005 to December 2006. There were 33 patients identified: 17 with benign and 16 with malignant pathologies. In all of the subjects, conventional MR imaging sequences were performed apart from diffusion-weighted sequences. The mean ADC values in the benign and malignant groups were compared using an unpaired t test with unequal variance with a P RESULTS: There was a statistically significant difference (P = .004) between the mean ADC values (in 10−3 mm2/s) in the benign and malignant lesions (1.505 ± 0.487; 95% confidence interval, 1.305–1.706, and 1.071 ± 0.293; 95% confidence interval, 0.864–1.277, respectively). There were 2 malignant lesions with ADC values higher than 1.3 × 10−3 mm2/s and 5 benign lesions with ADC values less than 1.3 × 10−3 mm2/s. The lack of overlap of ADC values within 95% confidence limits suggests that a 3T ADC value of 1.3 × 10−3 mm2/s may be the threshold value for differentiation between benign and malignant head and neck lesions. CONCLUSION: ADC values of benign and malignant neck pathologies are significantly different at 3T imaging, though larger studies are required to establish threshold ADC values that can applied in daily clinical practice.
Melting and the vector Coulomb gas in two dimensions

The dislocation theory of two-dimensional melting due to Kosterlitz and Thouless is investigated for the triangular lattice, paying special attention to angular forces between dislocation pairs, which are equal in magnitude to the radial forces. Generalizing the dislocation Hamiltonian to an arbitrary vector Coulomb gas with different radial and angular interactions we find ${K}_{R}^{i}(T)\ensuremath{-}{K}_{R}^{i}({T}_{c}^{\ensuremath{-}})\ensuremath{\sim}{t}^{\overline{\ensuremath{\nu}}}$, where ${K}_{R}^{i}$ is a renormalized coupling which includes the screening effect of bound dislocation pairs, the superscript $i$ signifies either a radial, $r$, or angular, $\ensuremath{\theta}$ part and $t$ is the reduced temperature, $t=\frac{({T}_{c}\ensuremath{-}T)}{{T}_{c}}$. The exponent $\overline{\ensuremath{\nu}}$ varies as the ratio $\frac{{K}_{R}^{\ensuremath{\theta}}({T}_{c}^{\ensuremath{-}})}{{K}_{R}^{r}({T}_{c}^{\ensuremath{-}})}$ is changed and is equal to 0.3696... for the physical value of ${K}^{\ensuremath{\theta}}={K}^{r}$. In this case the shear and bulk elastic constants have the same temperature dependence as the ${K}_{R}^{i}$. We find that ${K}_{R}^{r}$ has finite universal value at ${T}_{c}$ and ${K}_{R}^{i}=0$ for $Tg{T}_{c}$, corresponding to metallic behavior of the vector Coulomb gas.
Link-Layer Traceback in Ethernet Networks

The design of the most commonly-used Internet and local area network protocols provide no way of verifying the sender of a packet is who it claims to be. A malicious host can easily launch an attack while pretending to be another host to avoid being discovered. To determine the identity of an attacker, an administrator can use traceback, a technique that determines the path of attack packets from the victim to the coordinator. Most traceback research has focused on IP and stepping-stone techniques and little has been conducted on the problem of data-link layer trace-back (DLT), the process of tracing frames from the network edge to the attack source. We propose a scheme called tagged-frame traceback (TRACK) that provides a secure, reliable DLT technique for Ethernet networks. TRACK defines processes for Ethernet switches and a centralized storage and lookup host. Simulation results indicate that TRACK provides accurate DLT operation while causing minimal impact on network and application performance.
National Toxicology Program Center for the Evaluation of Risks to Human Reproduction: Guidelines for CERHR Expert Panel members†

The National Toxicology Program Center for the Evaluation of Risks to Human Reproduction (NTPCERHR) was established at the National Institute of Environmental Health Sciences in 1998. The NTPCERHR’s primary activity is the evaluation of naturally occurring and synthetic chemicals for their potential to adversely affect reproduction and/or development in humans. These evaluations are accomplished through the efforts of independent panels of scientists representing a range of relevant scientific disciplines. Working with NTP-CERHR staff over a period of several weeks, an expert panel prepares a draft report on the subject chemical covering 1) chemistry, usage and exposure, 2) general toxicity, 3) developmental toxicity, and 4) reproductive toxicity. Then, at a public meeting, the expert panel completes the report by reviewing and editing the first four sections and preparing section 5) summaries, conclusions, and critical data needs. To aid the panels in their evaluations and to help ensure uniformity among reports, the NTP-CERHR developed guidelines for literature evaluation and expert panel report preparation. In developing these guidelines, the NTP-CERHR drew on documents published by three organizations: the Institute for Environmental Health Research (Moore et al., 1995), the International Agency for Research on Cancer (IARC, 1995), and the National Research Council (National Research Council, 2001). The NTP solicited public comments on the draft guidelines (HHS, 2001) and revised the guidelines based on the comments received. The current guidelines reflect additional revisions that have resulted from their use by 6 expert panels and in the preparation of 14 expert panel reports. The guidelines are published here, along with the NTP-CERHR Expert Panel Report on the Reproductive and Developmental Toxicity of Acrylamide, to make them available to a broader scientific audience.