290 research outputs found
Radiation effects on beta 10.6 of pure and europium doped KCl
Changes in the optical absorption coefficient as a result of X-ray and electron bombardment of pure KCl (monocrystalline and polycrystalline), and divalent europium doped polycrystalline KCl were determined. The optical absorption coefficients were measured by a constant heat flow calorimetric method. Both 300 KV X-irradiation and 2 MeV electron irradiation produced significant increases in beta 10.6, measured at room temperature. The X-irradiation of pure moncrystalline KCl increased beta 10.6 by 0.005/cm for a 113 MR dose. For an equivalent dose, 2 MeV electrons were found less efficient in changing beta 10.6. However, electron irradiation of pure and Eu-doped polycrystalline KCl produced marked increases in adsorption. Beta increased to over 0.25/cm in Eu-doped material for a 30 x 10 to the 14th power electrons/sq cm dose, a factor of 20 increase over unirradiated material. Moreover, bleaching the electron irradiated doped KCl with 649 m light produced and additional factor of 1.5 increase. These findings will be discussed in light of known defect-center properties in KCl
Generalized stacking fault energy surfaces and dislocation properties of aluminum
We have employed the semidiscrete variational generalized Peierls-Nabarro
model to study the dislocation core properties of aluminum. The generalized
stacking fault energy surfaces entering the model are calculated by using
first-principles Density Functional Theory (DFT) with pseudopotentials and the
embedded atom method (EAM). Various core properties, including the core width,
splitting behavior, energetics and Peierls stress for different dislocations
have been investigated. The correlation between the core energetics and
dislocation character has been explored. Our results reveal a simple
relationship between the Peierls stress and the ratio between the core width
and atomic spacing. The dependence of the core properties on the two methods
for calculating the total energy (DFT vs. EAM) has been examined. The EAM can
give gross trends for various dislocation properties but fails to predict the
finer core structures, which in turn can affect the Peierls stress
significantly (about one order of magnitude).Comment: 25 pages, 12 figure
Phase I Study of the Safety and Pharmacokinetics of Plerixafor in Children Undergoing a Second Allogeneic Hematopoietic Stem Cell Transplantation for Relapsed or Refractory Leukemia
AbstractThe safety, pharmacokinetics, and biological effect of plerixafor in children as part of a conditioning regimen for chemo-sensitization in allogeneic hematopoietic stem cell transplantation (HSCT) have not been studied. This is a phase I study of plerixafor designed to evaluate its tolerability at dose of .24 mg/kg given intravenously on day −4 (level 1); day −4 and day −3 (level 2); or day −4, day −3, and day −2 (level 3) in combination with fludarabine, thiotepa, melphalan, and rabbit antithymocytic globulin for a second allogeneic HSCT in children with refractory or relapsed leukemia. Immunophenotype analysis was performed on blood and bone marrow before and after plerixafor administration. Twelve patients were enrolled. Plerixafor at all 3 levels was well tolerated without dose-limiting toxicity. Transient gastrointestinal side effects of National Cancer Institute–grade 1 or 2 in severity were the most common adverse events. The area under the concentration-time curve increased proportionally to the dose level. Plerixafor clearance was higher in males and increased linearly with body weight and glomerular filtration rate. The clearance decreased and the elimination half-life increased significantly from dose level 1 to 3 (P < .001). Biologically, the proportion of CXCR4+ blasts and lymphocytes both in the bone marrow and peripheral blood increased after plerixafor administration
Short-Range Ising Spin Glass: Multifractal Properties
The multifractal properties of the Edwards-Anderson order parameter of the
short-range Ising spin glass model on d=3 diamond hierarchical lattices is
studied via an exact recursion procedure. The profiles of the local order
parameter are calculated and analysed within a range of temperatures close to
the critical point with four symmetric distributions of the coupling constants
(Gaussian, Bimodal, Uniform and Exponential). Unlike the pure case, the
multifractal analysis of these profiles reveals that a large spectrum of the
-H\"older exponent is required to describe the singularities of the
measure defined by the normalized local order parameter, at and below the
critical point. Minor changes in these spectra are observed for distinct
initial distributions of coupling constants, suggesting an universal spectra
behavior. For temperatures slightly above T_{c}, a dramatic change in the
function is found, signalizing the transition.Comment: 8 pages, LaTex, PostScript-figures included but also available upon
request. To be published in Physical Review E (01/March 97
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Characterization of composite high temperature superconductors for magnetic bearing applications
A study of high temperature superconductor composites for use in magnetic bearings applications is presented. Fabrication and characterization techniques are described. Magnetometry and mechanical force measurements are correlated with a particular emphasis on the role of superconductor particle size. Results are discussed in terms of fundamental limits of Meissner effect levitation. 21 refs., 11 figs., 1 tab
Time From Symptom Onset to Treatment and Outcomes after Thrombolytic Therapy
OBJECTIVES: This study sought to examine the relations among patient characteristics, time to thrombolysis and outcomes in the international GUSTO-I trial. BACKGROUND: Studies have shown better left ventricular function and decreased infarct size as well as increased survival with earlier thrombolysis, but the relative benefits of various thrombolytic agents with earlier administration are uncertain. METHODS: We evaluated the relations of baseline characteristics to three prospectively defined time variables: symptom onset to treatment, symptom onset to hospital arrival (presentation delay) and hospital arrival to treatment (treatment delay). We also examined the relations of delays to clinical outcomes and to the relative 30-day mortality benefit with accelerated tissue-type plasminogen activator (t-PA) versus streptokinase. RESULTS: Female, elderly, diabetic and hypertensive patients had longer delays at all stages. Previous infarction or bypass surgery was an additional risk factor for treatment delay. Early thrombolysis was associated with lower overall mortality rate ( 4 h, 9.0%), but no additional relative benefit resulted from earlier treatment with accelerated t-PA versus streptokinase (p = 0.38). Longer presentation and treatment delays were both associated with increased mortality rate (presentation delay 4 h, 8.6%; treatment delay 90 min, 8.1%). As time to treatment increased, the incidence of recurrent ischemia or reinfarction decreased, but the rates of shock, heart failure and stroke increased. CONCLUSIONS: Earlier treatment resulted in better outcomes, regardless of thrombolytic strategy. Elderly, female and diabetic patients were treated later, adding to their already substantial risk
Comprehensive Survey of SNPs in the Affymetrix Exon Array Using the 1000 Genomes Dataset
Microarray gene expression data has been used in genome-wide association studies to allow researchers to study gene regulation as well as other complex phenotypes including disease risks and drug response. To reach scientifically sound conclusions from these studies, however, it is necessary to get reliable summarization of gene expression intensities. Among various factors that could affect expression profiling using a microarray platform, single nucleotide polymorphisms (SNPs) in target mRNA may lead to reduced signal intensity measurements and result in spurious results. The recently released 1000 Genomes Project dataset provides an opportunity to evaluate the distribution of both known and novel SNPs in the International HapMap Project lymphoblastoid cell lines (LCLs). We mapped the 1000 Genomes Project genotypic data to the Affymetrix GeneChip Human Exon 1.0ST array (exon array), which had been used in our previous studies and for which gene expression data had been made publicly available. We also evaluated the potential impact of these SNPs on the differentially spliced probesets we had identified previously. Though the 1000 Genomes Project data allowed a comprehensive survey of the SNPs in this particular array, the same approach can certainly be applied to other microarray platforms. Furthermore, we present a detailed catalogue of SNP-containing probesets (exon-level) and transcript clusters (gene-level), which can be considered in evaluating findings using the exon array as well as benefit the design of follow-up experiments and data re-analysis
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1960
Recent Developments Affecting Golf Course Design (page 1) From the Editor (3) Five Year Results (3) Turf Management Club News (4) Quotes from 1960 Seniors (5) Poa annua - - Friend or Foe (6) The Horticulture Show (7) Cartoons (8) Message from the Winter School President of 1960 (10) The Most Outstanding Turf Senior for 1959 (10) The Value of the Proper Use of Lime (11) Summer Placement (12) A Greenhouse on the Golf Course (13) More Opportunities in the Future for the Aggressive Superintendent at Country Clubs (14) Soil, Sawdust and Turfgrass (15) Picture - Senior Stockbridge Turf majors (16) Picture - Freshman Stockbridge Turf majors (17) Susceptibility of Merion Bluegrass to Stripe Smut (18) Bents in the South (19) Picture - Honorary Members of Turf Management Club (20) Picture - Graduates of Winter School for Turf mangers- 1960 (21) Weather - We are Going to Have Weather, Whether or Not - What Should we Expect by O. Tennebaum & R. E. Lautzenheiser (A-1) The Nature of Winter Injury to Plants by Dr. Johnson Parker (A-1) Turf Problems: You Name it and We\u27ve Had It in \u2759 by Alexander Radko ad T.T. Taylor (A-3) Topdressing Experiences with Greens at Century by James Fulwider (A-5) Poa annua - Fairway Rennovation at winged Foot by Sherwood A. Moore (A-6) Winter Problems at Ekwanaok by Paul O\u27Leary (A-8) Progress Through Drainage by Kayem Ovian (A-10) Winter Injury on Home Lawns by Orlando Capizzi (A-12) The Status of Pre-emergence Chemicals for the Control of Crabgrass by Dr. E. Engel (A-12) Turf Nurseries - Establishment, Maintenance & Utilization by Robert Grant (A-14) Soil Compaction by Dr. R. B. Alderfer (A-16) Water Management Practices on Turf Areas by Dr. J.R. Watson (A-18) Getting to Know Your Members by Owen Griffith (A-23) New Trends in Clubhouse Landscaping by Alfred Boicourt (A-26) General Lawn Management (Alternate Session) Conserving Soil for a good Lawn by Dr. William G. Colby (A-27) Fertilizting and Liming by Dr. Joseph Steckel (A-28) Grasses and Grass Mixtures for New England Lawns by Dr. Robert Schery (A-29) The Care and Maintenance of Establishment Lawns by Dr. John R. Davi
High prevalence of lack of knowledge of symptoms of acute myocardial infarction inPakistan and its contribution to delayed presentationto the hospital
<p>Abstract</p> <p>Background</p> <p>We conducted an observational study to determine the delay in presentation to hospital, and its associates among patients experiencing first Acute Myocardial Infarction (AMI) in Karachi, Pakistan.</p> <p>Methods</p> <p>A hospital based cross-sectional study was conducted at National Institute of Cardiovascular Disease (NICVD) in Karachi. A structured questionnaire was used to collect data. The primary outcome was delay in presentation, defined as a time interval of six or more hours from the onset of symptoms to presentation to hospital. Logistic regression analysis was performed to determine the factors associated with prehospital delay.</p> <p>Results</p> <p>A total of 720 subjects were interviewed; 22% were females. The mean age (SD) of the subjects was 54 (± 12) years. The mean (SE) and median (IQR) time to presentation was 12.3 (1.7) hours and 3.04 (6.0) hours respectively. About 34% of the subjects presented late. Lack of knowledge of any of the symptoms of heart attack (odds ratio (95% CI)) (1.82 (1.10, 2.99)), and mild chest pain (10.05 (6.50, 15.54)) were independently associated with prehospital delay.</p> <p>Conclusion</p> <p>Over one-third of patients with AMI in Pakistan present late to the hospital. Lack of knowledge of symptoms of heart attack, and low severity of chest pain were the main predictors of prehospital delay. Strategies to reduce delayed presentation in this population must focus on education about symptoms of heart attack.</p
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