756 research outputs found

    Mitotic instability in benomyl-resistant transformants of a fluffy strain of Neurospora crassa

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    The isolation of the beta-tubulin gene from a benomyl-resistant Neurospora crassa strain (Orbach et al. 1986 Mol. Cell. Biol. 6:2452-2461) has provided a dominant selectable marker usable in transformation experiments with N. crassa

    New mutants of Neurospora crassa highly resistant to the microtubule inhibitor benomyl

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    Mutants of N. crassa highly resistant to benomyl with respect to hyphal growth were obtained by mutagenizing wild type strain St. Lawrence 74A or mutant Bml 511(r) which is moderately resistant to the fungicide. One of these, strain E1-91 that has a mutation mapping at the Bml (beta-tubulin) locus, showed temporary sensitivity to the benzimidazole

    The Concept of Ecologically Oriented Progress and Natural Resource Preservation

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    The most important issue of scientific and technological progress is considering the environment challenges of industrial development. It means that the progress must be ecologically oriented and environmentally friendly. The most adequate concept for the approach to the issue of "man - society – nature" relations is the ontology of the noosphere - the idea of a common space for human beings and nature. It presents an ideal example of an optimistic attitude towards the coordination between accelerating the scientific and technological development and natural resource saving. However, to maintain the balance between human needs and environmental processes determined by this concept, it is essential to include the lean production training into technological development of society

    Crossover between Equilibrium and Shear-controlled Dynamics in Sheared Liquids

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    We present a numerical simulation study of a simple monatomic Lennard-Jones liquid under shear flow, as a function of both temperature and shear rate. By investigating different observables we find that i) It exists a line in the (temperature-shear) plane that sharply marks the boarder between an ``equilibrium'' and a ``shear-controlled'' region for both the dynamic and the thermodynamic quantities; and ii) Along this line the structural relaxation time, is proportional to the inverse shear rate, i.e. to the typical time-scale introduced by the shear flow. Above the line the liquid dynamics is unaffected by the shear flow, while below it both temperature and shear rate control the particle motion.Comment: 14 pages, 5 figure

    INCIDENCE OF SYMPTOMATIC AND ASYMPTOMATIC \u3ci\u3ePLASMODIUM FALCIPARUM\u3c/i\u3e INFECTION FOLLOWING CURATIVE THERAPY IN ADULT RESIDENTS OF NORTHERN GHANA

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    Adult residents of holoendemic malaria regions in Africa have a naturally acquired immunity (NAI) to malaria that renders them more resistant to new infections, limits parasitemia, and reduces the frequency and severity of illness. Given such attributes, it is not clear how one might evaluate drug or vaccine efficacy in adults without serious confounding. To determine symptomatic and asymptomatic malaria attack rates in adults of northern Ghana, 197 men and women underwent curative therapy for any pre-existing malaria infections at the start of the high transmission (wet) season. They were monitored for first parasitemia and first clinical episode of infection by Plasmodium falciparum over a 20-week period (May–October 1996). The cumulative incidence of primary infection by P. falciparum was 0.98 and incidence density of infection was calculated to be 7.0 cases/person-year. Symptoms were reported by 19.5% of the individuals at the time of first recurrent parasitemia. Incidence of infection, parasite density, and the frequency of symptoms were comparable in males and females. The results suggest that NAI did not provide these adults with significant defense against rapid re-infection and suggest that this population-infection design could serve to demonstrate the efficacy of a drug or vaccine in preventing parasitemia

    Sheared Solid Materials

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    We present a time-dependent Ginzburg-Landau model of nonlinear elasticity in solid materials. We assume that the elastic energy density is a periodic function of the shear and tetragonal strains owing to the underlying lattice structure. With this new ingredient, solving the equations yields formation of dislocation dipoles or slips. In plastic flow high-density dislocations emerge at large strains to accumulate and grow into shear bands where the strains are localized. In addition to the elastic displacement, we also introduce the local free volume {\it m}. For very small mm the defect structures are metastable and long-lived where the dislocations are pinned by the Peierls potential barrier. However, if the shear modulus decreases with increasing {\it m}, accumulation of {\it m} around dislocation cores eventually breaks the Peierls potential leading to slow relaxations in the stress and the free energy (aging). As another application of our scheme, we also study dislocation formation in two-phase alloys (coherency loss) under shear strains, where dislocations glide preferentially in the softer regions and are trapped at the interfaces.Comment: 16pages, 11figure

    Identifying the electronic character and role of the Mn states in the valence band of (Ga,Mn)As

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    We report high-resolution hard x-ray photoemission spectroscopy results on (Ga,Mn)As films as a function of Mn doping. Supported by theoretical calculations we identify, over the entire 1% to 13% Mn doping range, the electronic character of the states near the top of the valence band. Magnetization and temperature dependent core-level photoemission spectra reveal how the delocalized character of the Mn states enables the bulk ferromagnetic properties of (Ga,Mn)As.Comment: prl submitte

    QTL mapping of improving forage maize starch degradability in European elite maize germplasm

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    Improving maize starch content is of great importance for both forage and grain yield. In this study, 13 starch degradability traits were analyzed including percentage of the seedling area, floury endosperm, hard endosperm of total grain area, percentage of the floury endosperm surface, and vitreousness ratio surface hard: floury endosperm surface, etc. We mapped quantitative trait loci (QTL) in a biparental population of 309 doubled haploid lines (DHL) based on field phenotyping at two locations. A genetic linkage map was constructed using 168 SSR (simple sequence repeat) markers, which covered 1508 cM of the maize genome, with an average distance of 9.0 cM. Close phenotypic and genotypic correlations were found for all traits, and were all statistically significant (P = 0.01) at two locations. Major QTL for more than two traits were detected, especially in two regions in bins 4.05-4.06 and 7.04-7.05, associated with 13 and 9 traits, respectively. This study contributes to marker assisted breeding and also to fine mapping candidate genes associated with maize starch degradability

    Feasibility of Azacitidine Added to Standard Chemotherapy in Older Patients with Acute Myeloid Leukemia — A Randomised SAL Pilot Study

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    Introduction: Older patients with acute myeloid leukemia (AML) experience short survival despite intensive chemotherapy. Azacitidine has promising activity in patients with low proliferating AML. The aim of this dose-finding part of this trial was to evaluate feasibility and safety of azacitidine combined with a cytarabine- and daunorubicin-based chemotherapy in older patients with AML. Trial Design: Prospective, randomised, open, phase II trial with parallel group design and fixed sample size. Patients and Methods: Patients aged 61 years or older, with untreated acute myeloid leukemia with a leukocyte count of ,20,000/ml at the time of study entry and adequate organ function were eligible. Patients were randomised to receive azacitidine either 37.5 (dose level 1) or 75 mg/sqm (dose level 2) for five days before each cycle of induction (7+3 cytarabine plus daunorubicine) and consolidation (intermediate-dose cytarabine) therapy. Dose-limiting toxicity was the primary endpoint. Results: Six patients each were randomised into each dose level and evaluable for analysis. No dose-limiting toxicity occurred in either dose level. Nine serious adverse events occurred in five patients (three in the 37.5 mg, two in the 75 mg arm) with two fatal outcomes. Two patients at the 37.5 mg/sqm dose level and four patients at the 75 mg/sqm level achieved a complete remission after induction therapy. Median overall survival was 266 days and median event-free survival 215 days after a median follow up of 616 days. Conclusions: The combination of azacitidine 75 mg/sqm with standard induction therapy is feasible in older patients with AML and was selected as an investigational arm in the randomised controlled part of this phase-II study, which is currently halted due to an increased cardiac toxicity observed in the experimental arm. Trial Registration: This trial is registered at clinical trials.gov (identifier: NCT00915252)

    Evidences of vortex curvature and anisotropic pinning in superconducting films by quantitative magneto-optics

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    We present the experimental observation of magnetic field line curvature at the surface of a superconducting film by local quantitative magneto-optics. In addition to the knowledge of the full induction field at the superconductor surface yielding the quantitative observation of the flux line curvature, our analysis method allows also local value measurements of the electrical current density inside the sample. Thus, we study the interplay between the electrodynamic constraints dictated by the film geometry and the pinning properties of the superconductor. In particular, we investigate the anisotropic vortex-pinning, due to columnar defects introduced by heavy ion irradiation, as revealed in the local current density dependence on the vortex curvature during magnetic flux diffusion inside the superconducting film.Comment: 12 pages, 11 figures, to be submitted to Phys. Rev.
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