cssi/SciSciGPT-SciSciNet huggingface dataset:
Hedge fund attributes and volatility around equity offerings

The purpose of this paper is to explore the potential influence of hedge fund attributes on idiosyncratic volatility (IVOL) in excess stock returns for 705 firms undergoing seasoned equity offerings (SEOs). This investigation is important due to the pervasive concerns about the impact of hedge funds on volatility. We choose a time frame from 1999 to 2005 covering two periods that could impact IVOL differently: the internet-technology bubble period and the post-bubble period. Our time frame includes the breakpoint year of 2000 that marks a downward trend in IVOL from 2000 to 2008. We explore this IVOL drop for a sample of SEOs and find that the decline in IVOL for this sample can be primarily related to the rapid increase in the hedge fund industry size and to the increasing use of leverage by hedge funds. This trend is also related to the increasing use of a relative value (arbitrage) strategy and the decreasing use of an event-driven strategy. IVOL for our sample also appears to decrease with greater hedge fund performance except when hedge funds are riding the pre-SEO stock price run-up. The downward shift in IVOL for our SEO sample around their offering dates is better explained by hedge fund attributes than by non-hedge fund attributes. In conclusion, our findings suggest that the rapid increase in the hedge fund industry offer an explanation for the mysterious decline in IVOL that has been witnessed since 2000.
TU‐D‐224C‐01: Effects of Choice of the MLC Material On Neutron Dose Equivalent Outside of the Treatment Field in Proton Therapy

Purpose: To determine the effects of choice of MLC material on neutron dose equivalent outside of the treatment field in proton therapy.Method and Materials: A four‐dimensional GEANT4 Monte Carlo simulation of a commercially available proton therapy nozzle has been used to calculate the ratio of neutron dose equivalent to therapeuticproton absorbed dose (HN/DP). HN/DP varies significantly with proton beam energy, materials used in the nozzle, treatment technique, and range modulation. Technical specifications of the nozzle have been provided by the vendor. Lateral beam spreading is achieved primarily by binary pre‐scatterer foils and a double contoured scatterer. Modulation is generated by a stepped propeller positioned at nozzle entrance, and pre‐collimation is done by nickel inserts. A preliminary design of a multi‐leaf collimator has been added to the simulation, providing final collimation. Four different data sets have been generated, each one corresponding to a different MLC composition: tungsten, brass, iron and stainless steel. Results: A 200 MeV proton beam is used in order to produce a large circular treatment field with a 10 cm radius, a depth of penetration of approximately 22 cm, and an SOBP width of 10 cm. Neutron dose equivalents are calculated outside the treatment field at three distances from isocenter: 15 cm, 25 cm, and 47 cm (along beam direction). The highest HN/DP ratios are calculated for tungsten, and vary from 10 mSv/Gy at a distance of 15 cm off axis, to 0.7 mSv/Gy at 47.5cm off axis. Corresponding HN/DP ratios for stainless steel are 6.93 mSv/Gy and 0.46 mSv/Gy, representing the lowest calculated values. Conclusion: A steel MLC produces, on average, 45% less secondary neutron dose deposit compared to a tungstenMLC. The result indicates potential for dose reduction in proton therapy when a steel collimator is used instead of a tungstencollimator.
WE-B-BRA-01: TG-142: Quality Assurance for Medical Accelerators

The task group (TG) for quality assurance of medical accelerators was constituted by the American Association of Physicists in Medicine's Science Council, under the direction of the Radiation Therapy Committee and the Quality Assurance and Outcome Improvement Subcommittee. The report was published in the Journal of Medical Physics in September of 2009. [http://aapm.org/pubs/reports/RPT_142.pdf] The task group (TG #142) had two main charges. First to update, as needed, recommendations of Table II of the AAPM TG ▭ 40 Report on Quality Assurance, and second, to add recommendations for Asymmetric Jaws, Multileaf Collimation(MLC), and Dynamic/Virtual Wedges. The TG accomplished the update to TG▭40, specifying new test and tolerances, and has added recommendations for not only the new ancillary delivery technologies, but also for imaging devices that are part of the linear accelerator. The imaging devices include x▭ray imaging, photon portal imaging, and cone▭beam CT. The TG report was designed to account for the types of treatments delivered with the particular machine. For example, machines that are used for radiosurgery treatments, or intensity modulated radiotherapy(IMRT) require different tests and/or tolerances. There are specific recommendations for MLCquality assurance for machines performing IMRT. There are specific tables according to daily, monthly, and annual reviews, along with unique tables for wedge systems, MLC, and imaging checks. The report is geared to be flexible for the physicist to customize the QA program depending on clinical utility. This is consistent with the philosophy of TG▭100, “Method for Evaluating QA Needs in Radiation Therapy.” The report also gives recommendations as to action levels for the physicists to implement particular actions, whether they are inspection, scheduled action, or immediate and corrective action. The report also gives specific implementation recommendations regarding setup of a QA program by the physicist, such as; building a QA team, establishing procedures, training of personnel, documentation, and end▭to▭end system checks. The tabulated items of this report have been considerably expanded as compared with the original TG 40 report and the recommended tolerances accommodate differences of the intended functionality (i.e., non▭IMRT, IMRT, or Stereotactic Delivery). Learning Objectives: 1. To understand the updates to TG▭40 in the new TG▭142 report. 2. To understand the recommend QA tests for wedge, MLC, and imaging systems as they pertain to accelerator type and procedures performed (i.e. IMRT). 3. To understand the implementation plan and action level and response recommendations
Analysis of Coulter counting data from nanopores using clustering

Nanopores with diameters of 105nm have been used to detect 60nm diameter beads by Coulter counting. The Coulter counting is performed by applying a constant potential across the nanopore while recording the drop in ionic current upon passage of a nanobead. In this paper, we analyze the use of the amplitude of the current drop and its duration to infer useful information about the nanobead(s) passing through the pore. Analysis of the shape and duration of these current drops enables us to estimate the size distribution of the nanobeads. Current drops corresponding to complete passage of a nanobead through the pore is called an event. The proposed approach uses spectral clustering to cluster the drops in the feature domain as the shape of the clusters is unknown. Spectral clustering accurately finds the natural clusters and the outlying cluster. The outlying cluster is further clustered to find the categories of the events within it. (5 pages)
Serum androgens in hyperinsulinemic Pima Indian and obese Caucasian women and their response to short-term insulin infusion

Insulin resistance and its attendant hyperinsulinemia has been linked with hyperandrogenism. Insulin resistance is characteristic of the Pima Indians of the Gila River Indian community in central Arizona. Serum androgens, testosterone and dehydroepiandrosterone sulfate (DHEA-S) were quantitated at baseline and in response to low- and high-dose insulin infusion in 11 obese, hyperinsulinemic Pima Indian and 10 obese, hyperinsulinemic Caucasian women and were compared with baseline androgens in 16 nonobese Caucasian women. While there was no significant testosterone or DHEA-S response to short-term insulin infusion in either Pirnas or obese Caucasians, both these groups had higher baseline testosterone concentrations (67±6.5 ng/dl in the Pimas, 55±5.9 ng/dl in the obese Caucasians) as compared with the nonobese Caucasians (28±2 ng/dl; p<0.001). Baseline DHEA-S concentrations were not significantly different in the three groups. Given the hyperinsulinemic status of both the Pirnas and the obese Caucasians, the finding of higher testosterone concentrations in these subjects as compared with nonobese Caucasians supports a role for insulin in ovarian androgen production and demonstrates that hormonal interactions that may be operating in obese hyperinsulinemic Caucasian subjects also operate in obese, hyperinsulinemic Pima Indians.
Transition region of the Earth's upper mantle

The Earth's mantle is conventionally divided into three major subdivisions: the shallow mantle, the transition region and the lower mantle. High seismic velocity gradients extend from 400 km, the top of the transition region, to ~800 km. The relatively homogeneous part of the lower mantle starts near 800 km and extends to within several hundred kilometres of the core-mantle boundary. Major changes in mantle mineralogy occur near 400 and 650 km (refs 2-6). The question of whether these represent equilibrium phase boundaries in a homogeneous mantle or changes in chemistry is fundamental to many problems in earth sciences. There is abundant evidence that the Earth as a whole is a differentiated body and is inhomogeneous on many scales. For example, the extreme concentration of trace elements in the continental crust requires efficient extraction of these elements from all or most of the mantle. Nonetheless, the chemistry of the mantle remains a controversial issue which can be reduced to three basic questions: (1) is the mantle homogeneous in composition or is it chemically stratified? (2) Is the major-element chemistry of the mantle more similar to upper mantle peridotites or to chondrites? (3) What is the composition of the source region of basalts erupted at mid-ocean ridges? We address each of these questions using data from cosmochemistry, geochemistry, petrology, seismology and mineral physics.
Developmental changes in [3H]kainate binding in human brainstem sites vulnerable to perinatal hypoxia-ischemia

Abstract The human brainstem is especially susceptible to hypoxia-ischemia in early life. To test the hypothesis that the period of vulnerability of the developing human brainstem to hypoxia-ischemia correlates with a transient elevation in kainate receptor binding, we compared the quantitative distribution of [ 3 H]kainate binding in brainstem nuclei between four fetuses (19–26 gestational weeks), four infants (one to nine months), and three “mature” individuals (one child and two adults) without neurological disease. Quantitative tissues autoradiography was used. [ 3 H]Kainate binding decreased in all brainstem regions from early life to maturity with the most significant decreases occurring in nuclei thought to be especially vulnerable to perinatal hypoxia-ischemia (e.g. principal inferior olive, griseum pontis, inferior colliculus and reticular core). The highest binding in the fetal and infant period was found primarily in the major cerebellar-relay nuclei. In the inferior olive and arcuate nucleus, binding increased from the fetal to the infant period, and then fell 50–61% to low mature levels. In the griseum pontis, binding decreased 60% between the fetal and mature periods. In the reticular formation, binding fell 67–78% from the fetal to mature period. These data support a correlation between the period of brainstem vulnerability to hypoxia-ischemia in early life to a transient elevation in kainate binding, and are particularly relevant to the topographic brainstem patterns in perinatal hypoxia-ischemia of infantile olivary gliosis, pontosubicular necrosis and reticular core damage. Striking localization of [ 3 H]kainate binding to rhombic lip derivatives further suggests that kainate receptors may be involved in the development and function of human brainstem-cerebellar circuitry.
Working Together for the Common Good: Cell-Cell Communication in Bacteria

The 4th ASM Conference on Cell-Cell Communication in Bacteria was held in Miami, FL, from 6 to 9 November 2011. This review highlights three key themes that emerged from the many exciting talks and poster presentations in the area of quorum sensing: sociomicrobiology, signal transduction mechanisms, and interspecies communication.
Acceptance of Lesbian, Gay, Bisexual, and Transgender Patients, Attitudes About Their Treatment, and Related Medical Knowledge Among Osteopathic Medical Students

CONTEXT Limited research exists on the health issues faced by lesbian, gay, bisexual, and transgender (LGBT) patients, as viewed in the context of osteopathic medical education. A full understanding of current medical students' acceptance of, attitudes toward, and knowledge of these issues could lead to the development and incorporation of curricula focusing on the care of LGBT patients into colleges of osteopathic medicine (COMs). OBJECTIVE To determine among osteopathic medical students the levels of acceptance of LGBT patients, attitudes toward treating this population, and medically relevant knowledge about their distinct health-related issues. METHODS In August 2012, students at 6 COMs were sent an e-mail invitation that contained basic information about the study and a link providing access to an anonymous Web-based survey. Standard scales used in previous studies were compiled and individualized into 130 items for the purposes of the present study. RESULTS Of the 4112 osteopathic medical students contacted, 1698 (41.3%) entered the survey and 1335 (32.5%) completed it. Two hundred respondents (15%) self-identified as having a sexual orientation on the lesbian, gay, or bisexual (LGB) spectrum. Although respondents generally had favorable levels of acceptance of LGBT patients and positive attitudes toward treatment of this population, self-identified LGB students had even greater acceptance of LGBT patients (P<.001) and more positive attitudes toward their treatment (P<.001). When medically relevant knowledge of issues related to the health of LGBT patients was assessed, 125 respondents (12.9%) obtained a passing score of 7 or higher, with LGB students scoring significantly higher than students whose self-identified sexual orientation was heterosexual only (P=.01). Differences in the levels of acceptance of (P=.008), treatment attitudes toward (P=.001), and relevant medical knowledge (P=.05) pertaining to LGBT patients were noted between respondents from the 6 COMs. CONCLUSION The results suggest that even though osteopathic medical students had mostly positive personal attitudes and treatment attitudes toward LGBT patients, some disparities were still present. Also, students lacked adequate knowledge of the unique medical issues faced by the LGBT population. In the future, students should be given more training to effectively treat LGBT patients and their health-related issues.
Multi-view Wireless Video Streaming Based on Compressed Sensing: Architecture and Network Optimization

Multi-view wireless video streaming has the potential to enable a new generation of efficient and low-power pervasive surveillance systems that can capture scenes of interest from multiple perspectives, at higher resolution, and with lower energy consumption. However, state-of-the-art multi-view coding architectures require relatively complex predictive encoders, thus resulting in high processing complexity and power requirements. To address these challenges, we consider a wireless video surveillance scenario and propose a new encoding and decoding architecture for multi-view video systems based on Compressed Sensing (CS) principles, composed of cooperative sparsity-aware block-level rate-adaptive encoders, feedback channels and independent decoders. The proposed architecture leverages the properties of CS to overcome many limitations of traditional encoding techniques, specifically massive storage requirements and high computational complexity. It also uses estimates of image sparsity to perform efficient rate adaptation and effectively exploit inter-view correlation at the encoder side.Based on the proposed encoding/decoding architecture, we further develop a CS-based end-to-end rate distortion model by considering the effect of packet losses on the perceived video quality. We then introduce a modeling framework to design network optimization problems in a multi-hop wireless sensor network. Extensive performance evaluation results show that the proposed coding framework and power-minimizing delivery scheme are able to transmit multi-view streams with guaranteed video quality at low power consumption.
On the effectiveness of secret key extraction from wireless signal strength in real environments

We evaluate the effectiveness of secret key extraction, for private communication between two wireless devices, from the received signal strength (RSS) variations on the wireless channel between the two devices. We use real world measurements of RSS in a variety of environments and settings. Our experimental results show that (i) in certain environments, due to lack of variations in the wireless channel, the extracted bits have very low entropy making these bits unsuitable for a secret key, (ii) an adversary can cause predictable key generation in these static environments, and (iii) in dynamic scenarios where the two devices are mobile, and/or where there is a significant movement in the environment, high entropy bits are obtained fairly quickly. Building on the strengths of existing secret key extraction approaches, we develop an environment adaptive secret key generation scheme that uses an adaptive lossy quantizer in conjunction with Cascade-based information reconciliation [7] and privacy amplification [14]. Our measurements show that our scheme, in comparison to the existing ones that we evaluate, performs the best in terms of generating high entropy bits at a high bit rate. The secret key bit streams generated by our scheme also pass the randomness tests of the NIST test suite [21] that we conduct.
Factors Associated with Glaucoma after Penetrating Keratoplasty

We conducted a retrospective analysis of 80 eyes that underwent penetrating keratoplasties to determine the factors associated with early (less than three months) and late (more than three months) postoperative increases in intraocular pressure. The patients ranged in age from 14 to 91 years (mean age, 58.5 years). The 56 patients with aphakic eyes had a mean age of 64 years and the 24 patients whose eyes had lenses had a mean age of 48 years. In the 17 eyes with preoperative glaucoma, the intraocular pressure was controlled with medication (mean intraocular pressure, 17.6 mm Hg; range, 10 to 21 mm Hg). The follow-up periods ranged from 12 to 26 months (mean, 22 months). Of the 80 eyes, 25 had early increases in intraocular pressure and 23 had late increases. Twenty eyes showed increases during both periods. Of the 17 eyes with preoperative glaucoma, 14 had early increases and 15 had late increases (P
Determination of enantiomeric composition of ibuprofen in bulk drug by proton nuclear magnetic resonance spectroscopy with a chiral lanthanide chelate

Abstract The enantiomeric composition of ibuprofen was determined in a simple and reliable manner by proton nuclear magnetic resonance spectroscopy with a chiral lanthanide chelate. Optimum complexation with the europium (III) chelate took place in CCl4 after conversion of the enantiomeric sample into a mixture of methyl esters. The optimization of the experimental conditions in terms of substrate concentration and lanthanide chelate to substrate molar ratio led to two sets of signals of utility for quantitative purposes. Analysis of synthetic enantiomeric mixtures by the proposed method demonstrated excellent agreement between the assay results and the known masses of each enantiomer present in the mixture samples. The average ± S.D. recovery values were 99.39 ± 0.92 and 99.42 ± 0.68% (n = 10) of (S)-(+)-ibuprofen depending on whether the quantitation was based on the α-methyl protons or ester methyl protons, respectively.
Calculation of crystal truncation rod structure factors for arbitrary rational surface terminations

The technique of crystal truncation rod (CTR) diffraction is widely used for studying the structure of crystalline surfaces and interfaces. The theory and experimental details of the technique are well established; however, published methods for structure-factor calculations are typically based on a simple surface cell geometry. A method is presented for determining a surface coordinate system which results in a reciprocal lattice that is simply defined in terms of the surface termination. Based on this surface coordinate system, a general formalism for the calculation of CTR structure factors is re-derived, which may be easily applied to any surface that can be represented as a rational plane of a bulk crystal system.
Considerations in the determination by microdialysis of resting extracellular amino acid concentrations and release upon spinal cord injury

The following issues are further addressed: (1) Is there considerable leakage of amino acids from the circulation into the space around microdialysis probes, or are amino acid concentrations naturally much higher in the interstitial space than is generally thought? (2) Do observed high interstitial concentrations or depletion of substances in the intracellular space by microdialysis affect release measurements upon spinal cord injury? Amino acid concentrations around microdialysis fibres in the spinal cord of rats were found to approach those in the circulation and to be much higher than interstitial concentrations previously estimated in the CNS. However, much lower concentrations of amino acids were derived in the hippocampus by analogous experiments. Considerable Evans Blue/albumin leaked from the circulation into the interstitial space in the spinal cord immediately after fibre insertion. However, this movement diminished considerably by 4 h later, demonstrating substantial resealing of the blood-brain barrier, at least to large molecules. There is either substantial damage-induced movement of amino acids from the circulation into the dialysis zone after insertion of a microdialysis probe, or there is much less impediment to movement of amino acids across the blood-brain barrier in the spinal cord than in the brain. At low flow rates through the fibre, adding concentrations of amino acids to the inside of the fibre equal to the concentrations around the fibre to prevent their depletion by removal through the microdialysis fibre did not affect increases in concentrations of amino acids in microdialysates following injury. Thus the high concentrations of amino acids present around microdialysis fibres following their insertion do not seem to disturb measurements of amino acid release upon spinal cord injury.
A Jewish “Nature Preserve”: League of Nations Minority Protections in Nazi Upper Silesia, 1933–1937

In October 1936, Herbert Levy, a thirty-year-old German Jew living in Breslau, the capital of Silesia, moved to the eastern stretches of the region in order to become a doctor. Against all odds and repressive trends in Nazi Germany at the time, Levy applied for a spot to study medicine in Hindenburg, a mining town near the Polish-German border. While his application was predictably rejected based on his Jewish identity, Levy's response was less predictable, at least to an outsider. He appealed his case, arguing that he had the law on his side. Levy was right. Although more than three years of Nazi decrees and persecution had driven many Jewish doctors out of the practice and made the study of medicine all but impossible, Levy enjoyed the protections of international law.
Adherence to PIOPED II investigators' recommendations for computed tomography pulmonary angiography.

Abstract Background Computed tomography (CT) pulmonary angiography use has increased dramatically, raising concerns for patient safety. Adherence to recommendations and guidelines may protect patients. We measured adherence to the recommendations of Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED II) investigators for evaluation of suspected pulmonary embolism and the rate of potential false-positive pulmonary embolism diagnoses when recommendations of PIOPED II investigators were not followed. Methods We used a structured record review to identify 3500 consecutive CT pulmonary angiograms performed to investigate suspected pulmonary embolism in 2 urban emergency departments, calculating the revised Geneva score (RGS) to classify patients as "pulmonary embolism unlikely" (RGS≤10) or "pulmonary embolism likely" (RGS>10). CT pulmonary angiograms were concordant with PIOPED II investigator recommendations if pulmonary embolism was likely or pulmonary embolism was unlikely and a highly sensitive D-dimer test result was positive. We independently reviewed 482 CT pulmonary angiograms to measure the rate of potential false-positive pulmonary embolism diagnoses. Results A total of 1592 of 3500 CT pulmonary angiograms (45.5%) followed the recommendations of PIOPED II investigators. The remaining 1908 CT pulmonary angiograms were performed on patients with an RGS≤10 without a D-dimer test (n=1588) or after a negative D-dimer test result (n=320). The overall rate of pulmonary embolism was 9.7%. Potential false-positive diagnoses of pulmonary embolism occurred in 2 of 3 patients with an RGS≤10 and a negative D-dimer test result. Conclusions Nonadherence to recommendations for CT pulmonary angiography is common and exposes patients to increased risks, including potential false-positive diagnoses of pulmonary embolism.
Disparities in immunizations among elderly Medicare beneficiaries, 2000 to 2002.

Abstract Background Research reveals that influenza and pneumococcal immunization rates among blacks, Asians, and Hispanics significantly trail those of whites. This 2003 study examines recent trends and disparities for influenza and pneumococcal immunizations among elderly, non-institutionalized Medicare beneficiaries. Methods National samples of approximately 179,000 Medicare fee-for-service beneficiaries were surveyed by mail and telephone each year from 2000 to 2002. Outcomes include self-reported influenza immunization in the previous year and receipt of a pneumococcal immunization ever. Results Influenza immunization dipped in 2001 (69%) and almost rebounded to its 2000 level (73%) in 2002 (72%). Very substantial racial and ethnic disparities in the receipt of this preventive service exist between non-Hispanic blacks and Hispanics relative to non-Hispanic whites. Pneumococcal immunization increased by 2% annually (61%, 63%, and 65%) for the same years. However, very substantial racial and ethnic disparities in the receipt of this preventive service also exist between non-Hispanic blacks, Asians/Pacific Islanders, and Hispanics relative to non-Hispanic whites. Conclusions Younger, healthier, elderly persons must be encouraged to receive these immunizations to achieve the 2010 goal of 90% immunization. To reach that goal with no disparities, special efforts will be needed to target racial/ethnic minorities.
Age changes of the vascular pattern of the human dental pulp

Abstract A study is presented for the purpose of showing the change in vascular architecture of the human dental pulp with age. It is shown that as age increases, the number of vascular structures decreases, primarily at the expense of vessel reduction in the sub-odontoblastic layer of the pulp. It is demonstrated that the human pulp has a natural arterio-venous shunt system.
On the collective contribution to the surface energy of simple metals

Abstract A recent analysis by Feibelman of the contribution of collective modes to the surface energy is re-examined. When sum rule considerations are studied, his negative energy results are found to be spurious.
Anaerobic digestion of swine manure at various influent solids concentrations

Abstract The objective of the work described in this paper was to operate an anaerobic digester on swine manure at the highest possible influent Volatile Solids concentration. As influent Volatile Solids concentration increased, less methane was produced per gram of Volatile Solids added to the digester. However, volumetric efficiency (litres of CH 4 produced per litre of digester) increased up to an influent solids concentration of 70 g litre −1 and then decreased. Swine manure was converted to methane via anaerobic fermentation at influent Volatile Solids concentrations up to 97 g of Volatile Solids per litre. A relationship was evaluated which relates methane production per gram of Volatile Solids added, and methane production per volume of digester, to hydraulic retention time and influent Volatile Solids concentration.
Enzymatic analysis of total- and HDL-cholesterol: comparison with the standardized Liebermann-Burchard method used by the Lipid Research Clinics program.

Abstract We compared two enzymatic cholesterol methods with the standardized chemical method used in the Lipid Research Clinic's (LRC) program. The methods were used to measure total cholesterol and high density lipoprotein (HDL) cholesterol in heparin-MnCl2 supernatants of 1812 sera collected over a 16-mth period from subjects who were sampled as part of the Hispanic Health and Nutrition Examination Survey. Thirty percent of the subjects had fasted for 12 h or more before venepuncture. The enzymatic total cholesterol values were 1.4–1.8% lower than the LRC method and both enzymatic methods correlated highly with the LRC method ( r > 0.97). The enzymatic HDL cholesterol values were 2.4 and 6.4% higher than the LRC method, and the correlation between the enzymatic and LRC methods was > 0.93. The differences between the enzymatic and LRC methods were the same in samples from fasting and non-fasting subjects.
Chemical synthesis of [1β-3H]1α,25-dihydroxyvitamin D3 and [1α-3H]1β,25-dihydroxyvitamin D3: Biological activity of 1β,25-dihydroxyvitamin D3

The simple three-step preparation of [1β-3H]1α,25-dihydroxyvitamin D3 and [1α-3H]1β,25-dihydroxyvitamin D3 from 1α,25-dihydroxyvitamin D3 is described. In the rat, 1β,25-dihydroxyvitamin D3, when compared with its α-epimer, did not stimulate intestinal calcium transport or bone calcium mobilization at doses 1000-fold higher than the doses of the natural hormone, 1α,25-dihydroxyvitamin D3.
Allogeneic bone marrow transplant in pediatric patients with high-risk hematopoietic malignancies early in the course of their disease.

Purpose The purpose of this study was to investigate the role of bone marrow transplant (BMT) early in the course of disease for pediatric patients with high-risk leukemia using a preparatory regimen of fractionated total body irradiation (FTBI) and etoposide (VP-16). Patients and Methods Those studied were 33 patients aged ≤18 years with either acute leukemia in first complete remission (CR) (n = 29) or chronic myelogenous leukemia (CML) in first chronic phase (n = 4) who received 1,320 cGy FTBI followed by highdose VP-16 (60 mg/kg) as a preparatory regimen for BMT from matched sibling donors. Patients with acute leukemia included 18 with acute nonlymphocytic leukemia (ANLL), one with biphenotypic acute leukemia (BAL), and 10 with selected “high-risk” acute lymphocytic leukemia (ALL). Patients with ALL were selected for a high risk for recurrence: those who failed standard remission induction chemotherapy, had a t(9;22) or t(4;11) chromosomal translocation, or had certain clinical high-risk features. Results At the time of analysis, 28 patients are alive, all of them in continued complete remission for 1.1-7.8 years (median, 5.3 years; mean, 4.9 years). The Kaplan-Meier projected event-free survival (EFS) is 84.5% at 7 years, and the actuarial recurrence hazard is 6.5%. All surviving patients have a performance status of >80%. Conclusion This result of early BMT in a two-institution study of pediatric patients with hematopoietic malignancies suggests that (a) matched sibling allogeneic BMT after conditioning with FTBI and high-dose VP-16 is an excellent treatment for pediatric patients with high-risk leukemia, and (b) children may have a better prognosis than adults treated with allogeneic BMT. Larger multiinstitutional cooperative trials for pediatric patients are needed to confirm this result.
UV detective quantum efficiency measurements

We have been testing the vacuum ultraviolet (UV) response of several types of detectors, supporting investigators developing photodiodes made of GaN, near UV photocathodes, and Electron-Bombarded CCDs (EBCCDs). We are currently supporting 4 independent research groups developing GaN most of which have produced devices with significant sensitivity down to 1200 Angstroms. Over the past year, we have also tested bare CCDs with coatings to enhance ultraviolet response. Detectors based on microchannel plate (MCP) have been used extensively for a wide variety of NASA mission and continue to be the standard to beat. Two particularly promising detector technologies are (1) EBCCDs which offer an immediate factor of 3 - 4 improvement in sensitivity and (2) devices made of GaN or GaAlN which may eventually offer factors of 6 - 8 increased sensitivity, both compared to MCPs for wavelengths between 1200 to 3000 Angstroms. We present latest results and plans to expand our vacuum UV testing.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
K − -Meson Scattering in Nuclear Emulsion

Elastic single scatterings of ${K}^{\ensuremath{-}}$ mesons by nuclei of a dilute $G5$ photographic emulsion have been experimentally measured for energies between 30 and 80 Mev. Accurate numerical calculations of the differential scattering cross sections have been carried out by solving a Klein-Gordon wave equation for an optical-model potential of the Woods-Saxon form. Experimental and theoretical results are in good agreement both on an absolute and on a relative-variation basis if the real part of the ${K}^{\ensuremath{-}}$-nuclear potential is attractive. The connection with low-energy ${K}^{\ensuremath{-}}$-nucleon scattering is discussed.
Effective use of stranded renewable energy

The purpose of this paper is to suggest where immediate research and development should be focused to put us in the best position to deal with an unexpected energy crisis that might suddenly make our current infrastructure less effective.
Software defined radio for passive sensor interrogation

The software defined radio (SDR) provides a unique platform to interrogate passive, wireless sensors. The SDR platform defines many radio functions in software, rather than hardware. This allows for a very versatile interrogation platform that can be quickly reconfigured for diverse scenarios. This paper investigates the Universal Software Radio Peripheral (USRP), a commercial SDR developed by Ettus ResearchTM, to determine its viability to interrogate passive, wireless sensors. In particular, the N200 USRP and the WBX daughterboard are considered because they allow for the greatest possible bandwidth for this platform (40MHz) and frequency tuning that is ideal for surface acoustic wave (SAW) sensor interrogation (50MHz-2.2GHz). In the default operation mode, the USRP continuously streams data to and from the host computer. The host computer generates samples for transmission and processes any received samples. Synchronization of the transmit and receive chains becomes difficult due to latency in the communication medium (USB or Ethernet) between the host and USRP. While this mode is sufficient for most narrowband applications, wideband applications are more difficult to achieve because of the high sampling rates required (even in a baseband system such as the USRP). A prototype transceiver (passive tag reader) is developed by modifying the N200 FPGA to introduce new functionality to the USRP. These modifications include a custom interrogation signal generator (linear chirp) and triggering of the receiver based on the transmission state and desired listening time. These modifications are discussed and the modified transmit and receive characteristics are analyzed. Finally, a passive, wireless SAW OFC sensor is interrogated to demonstrate performance as a passive sensor transceiver.
Correlated-electron description of the photophysics of thin films of π -conjugated polymers

We extend the Mulliken theory of ground-state charge transfer in a donor-acceptor complex to excited-state charge transfer between pairs of identical $\ensuremath{\pi}$-conjugated oligomers, one of which is in the optically excited state and the other is in the ground state, leading to the formation of a charge-transfer exciton. Within our theory, optical absorptions from the charge-transfer exciton should include a low-energy intermolecular charge-transfer excitation, as well as distinct intramolecular excitations from both the neutral delocalized exciton component and the Coulombically bound polaron-pair component of the charge-transfer exciton. We report high-order configuration-interaction calculations for pairs of oligomers of polyparaphenylenevinylene (PPV) that go beyond our previous single configuration-interaction calculation and find all five excited-state absorptions predicted using heuristic arguments based on the Mulliken concept. Our calculated excited-state absorption spectrum exhibits strong qualitative agreement with the complete wavelength-dependent ultrafast photoinduced absorption in films of PPV derivatives, suggesting that a significant fraction of the photoinduced absorption here is from the charge-transfer exciton. We make detailed comparisons to experiments and a testable experimental prediction.
Validity of the Rokeach Value Survey.

The study evaluated the construct validity of the Rokeach Value Survey (RVS). Rokeach has presented factor analytic evidence that his instrument has the theorized dimensions. However, his results w...
SPAN-Xb expression in myeloma cells is dependent on promoter hypomethylation and can be upregulated pharmacologically

SPAN-Xb is a novel cancer-testis antigen in multiple myeloma (MM). In this study, we determined the mechanisms regulating SPAN-Xb expression in MM. SPAN-Xb promoter sequence was first cloned into the CAT-reporter vector to determine the role of promoter methylation in the regulation of gene expression. Tumor cells were treated with 5-azacytidine and a panel of cytokines were used to determine their ability to induce SPAN-Xb expression. Bisulfite conversion with sequence analysis was applied to a panel of tumor cells and normal tissues to correlate the CpG dinucleotide hypomethylation and SPAN-Xb expression. We found that SPAN-Xb promoter function could be silenced by methylation. 5-Azacytidine induced promoter hypomethylation and resulted in SPAN-Xb expression, at both the transcript and protein levels. Hypomethylation of the CpG dinucleotides at positions -310, -307, -299 and -221 within the SPAN-Xb promoter strongly predict for SPAN-Xb expression. Both IL-7 and GM-CSF were also able to upregulate the expression of SPAN-Xb in myeloma cells, but only after the promoter sequence has been hypomethylated. Our results provide the first evidence showing the role of promoter methylation in the primary regulation of SPAN-Xb and the ability of IL-7 and GM-CSF to further enhance SPAN-Xb gene and protein expression in myeloma cells.
Heroin discriminative stimulus effects of methadone, LAAM and other isomers of acetylmethadol in rats

Abstract Rationale. LAAM (α-l-acetylmethadol) is a derivative of the synthetic mu-opiate agonist methadone and is one of the four isomers of acetylmethadol. Methadone and LAAM have similar pharmacological properties and both are approved medications for the treatment of heroin dependency disorders. Few studies have reported on the pharmacology of acetylmethadol's other isomers and most of these have focused on their potential analgesic activity. Objectives. The purpose of the present investigation was to examine the discriminative stimulus effects of LAAM, the other isomers of acetylmethadol, and methadone in rats trained to discriminate heroin from water, and to compare the duration of the discriminative stimulus effects of heroin, methadone, and LAAM. Methods. Long-Evans rats were trained to discriminate 0.3 mg/kg heroin from water under a fixed ratio 10 (FR10) schedule of food reinforcement. Dose-response functions for heroin, methadone, LAAM, three other isomers of acetylmethadol: α-d-acetylmethadol, β-d-acetylmethadol, β-l-acetylmethadol, and its precursor, β-l-methadol were examined. Additionally, the time course effects for heroin, methadone, and LAAM were examined. Results. LAAM and methadone dose-dependently occasioned heroin-like discriminative stimulus effects. Two of acetylmethadol's isomers, α-d-acetylmethadol and β-d-acetylmethadol, were more potent than LAAM in producing heroin-like effects. The β-l-methadol precursor and β-l-acetylmethadol did not fully substitute for heroin's discriminative stimulus. LAAM elicited heroin-like discriminative stimulus effects for at least 6 h and generated partial generalization up to 36 h following administration. Conclusions. Methadone, LAAM, β-d-acetylmethadol and α-d-acetylmethadol, but not β-l-acetylmethadol and β-l-methadol evoke heroin-like discriminative stimulus effects.
Random number generators: Pretty good ones are easy to find

A popular conception is that random number generators are very difficult to build. I informally discuss some easily programmed, easily remembered, random number generators. Simple graphical techniques are introduced for assessing the quality of the generators with little training. To encourage reader involvement, computational recipes are included.
Lyapunov exponents for nonlinear systems with Poisson white noise

Abstract The stability analysis of the solution of stochastic differential equations based on Lyapunov exponents is a topic of active research in applied mathematics, physics, chemistry, and many other engineering fields. The analysis identifies subsets in the space of the parameters of a stochastic differential equation for which the solution of this equation remains bounded in some sense as time increases indefinitely. However, Lyapunov exponents have been calculated only for the solutions of stochastic differential equations driven by Gaussian white noise. This is a significant limitation because many stochastic disturbances are not Gaussian. This paper calculates Lyapunov exponents for stochastic differential equations with Poisson white noise, defined as the formal derivative of the compound Poisson process. The analysis is based on a generalized version of the classical Ito differentiation formula.
Efficient in vitro synthesis of biologically active RNA and RNA hybridization probes from plasmids containing a bacteriophage SP6 promoter

A simple and efficient method for synthesizing pure single stranded RNAs of virtually any structure is described. This in vitro transcription system is based on the unusually specific RNA synthesis by bacteriophage SP6 RNA polymerase which initiates transcription exclusively at an SP6 promoter. We have constructed convenient cloning vectors that contain an SP6 promoter immediately upstream from a polylinker sequence. Using these SP6 vectors, optimal conditions have been established for in vitro RNA synthesis. The advantages and uses of SP6 derived RNAs as probes for nucleic acid blot and solution hybridizations are demonstrated. We show that single stranded RNA probes of a high specific activity are easy to prepare and can significantly increase the sensitivity of nucleic acid hybridization methods. Furthermore, the SP6 transcription system can be used to prepare RNA substrates for studies on RNA processing (1,5,9) and translation (see accompanying paper).
Liver regeneration: cultrual characteristics of remnant liver cells following a second partial hepatectomy.

When a 38% hepatic resection (rat) is followed in 24–72 h by a 30% hepatic resection (in the same animal), in vitro cell survival is observed in liver remnant tissue removed at any interval following the second resection.
Quantitative determination of free glycerol and myo-inositol from plasma and tissue by high-performance liquid chromatography

A high-performance liquid chromatographic method that accurately measures glycerol and myo-inositol from plasma and tissue is described. The method incorporates a pre-column derivatization reaction using aqueous extracts with benzoyl chloride as a modifying agent. The benzoylated derivatives are isolated by HPLC using reversed-phase gradient chromatography and quantified via absorbance detection at 231 nm. The benzoylated derivatives of glycerol and myo-inositol are well resolved from other known carbohydrates, internal standard and other contaminants encountered within samples and during incubation. The benzoylation of these analytes reach a maximum between 3.5 and 6 h of incubation and are stable for at least 24 days at 4 degrees C. The limit of quantization (LOQ) of glycerol was equal to 2.5 nmol/ml plasma and 6.4 nmol/g tissue and the LOQ of myo-inositol was 1.8 nmol/ml plasma and 3.6 nmol/g tissue. Incubation of known standards and samples with benzoyl chloride at 40 degrees C for 4 h showed fully benzoylated products as determined by mass spectral analysis. Calibration curves were linear between 2.7 and 174 nmol for glycerol and 1.4-89 nmol for myo-inositol. Comparison of tissue and plasma concentrations of glycerol and myo-inositol found using this method are in good agreement with other reported values using other techniques.
Novel use of anaerobically induced promoter, dmsA, for controlled expression of fragment C of tetanus toxin in live attenuated Salmonella enterica serovar Typhi strain CVD 908-htrA.

Abstract The anaerobically induced promoter dmsA (P dmsA ) was adapted to optimize in vivo expression of foreign antigens in attenuated Salmonella enterica serovar Typhi live vector vaccines CVD 908- htrA . P dmsA from Escherichia coli and two derivatives, P dmsA 2 and P dmsA 3 were cloned into a plasmid driving the expression of a gene encoding tetanus toxin fragment C. Expression of fragment C varied from a low level induced by pTET dmsA , to moderate and high levels induced, respectively, by pTET dmsA 2 and pTET dmsA 3. Mice were immunized intranasally with CVD 908- htrA harboring pTET dmsA2 or pTET dmsA3 , and the serum antitoxin response was compared to that elicited by CVD 908- htrA (pTET nir 15) (P nir 15 is a benchmark anaerobically activated promoter). S. Typhi carrying pTET dmsA2 elicited modest tetanus antitoxin titers while S. Typhi harboring pTET dmsA3 generated elevated titers (GMT=55 384) that were higher than elicited by pTET nir 15 (GMT=4354) ( P =0.007). Mice immunized with CVD 908- htrA carrying pTET dmsA3 and pTET nir 15 survived tetanus toxin challenge. P dmsA derivatives are attractive promoters for in vivo expression of foreign genes in attenuated live vector vaccines.
Central supersensitivity to norepinephrine and amphetamine following brain chemical sympathectomy by 6-hydroxydopamine.

Abstract The results of this study further document the establishment of central supersensitivity to norepinephrine (NE) and the sympathomimetic d-amphetamine (d-Amp) following prolonged interruption of catecholaminergic neuronal transmission after treatment with 6-hydroxydopamine (6-OHDA). A strain of mice known to be insensitive to injections of NE and d-Amp were made very sensitive by utilizing 6-OHDA. The enhancement of the d-Amp response is discussed in terms of both indirect and direct development of supersensitivity to d-Amp.
Purification of reticulocyte ribosomes using polyuridylic acid: sepharose chromatography.

Abstract Deoxycholate-KCl washed reticulocyte ribosomes are purified by affinity chromatography using Sepharose columns to which polyuridylic acid has been covalently bound. Upon passage through the column under nonenzymic conditions (high Mg 2+ :K + ratio) approximately 10% of the ribosomes are retained. These ribosomes are then eluted with a buffer containing a high K + :Mg 2+ ratio and are assayed for activity in various steps of the elongation process of protein synthesis. Approximately a 3- to 4-fold increase in the various activities compared with control ribosomes is obtained.