111 research outputs found


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    The title compound, C19H10BrCl2F3N4O, is an imine with an overall Y shape. The dihedral angles between the pyrazole ring and the methoxy- and trifluoromethyl-substituted benzene ring planes are 88.4 (2) and 65.8 (2)°, respectively

    Randomized algorithms for fully online multiprocessor scheduling with testing

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    We contribute the first randomized algorithm that is an integration of arbitrarily many deterministic algorithms for the fully online multiprocessor scheduling with testing problem. When there are two machines, we show that with two component algorithms its expected competitive ratio is already strictly smaller than the best proven deterministic competitive ratio lower bound. Such algorithmic results are rarely seen in the literature. Multiprocessor scheduling is one of the first combinatorial optimization problems that have received numerous studies. Recently, several research groups examined its testing variant, in which each job JjJ_j arrives with an upper bound uju_j on the processing time and a testing operation of length tjt_j; one can choose to execute JjJ_j for uju_j time, or to test JjJ_j for tjt_j time to obtain the exact processing time pjp_j followed by immediately executing the job for pjp_j time. Our target problem is the fully online version, in which the jobs arrive in sequence so that the testing decision needs to be made at the job arrival as well as the designated machine. We propose an expected (φ+3+1)(3.1490)(\sqrt{\varphi + 3} + 1) (\approx 3.1490)-competitive randomized algorithm as a non-uniform probability distribution over arbitrarily many deterministic algorithms, where φ=5+12\varphi = \frac {\sqrt{5} + 1}2 is the Golden ratio. When there are two machines, we show that our randomized algorithm based on two deterministic algorithms is already expected 3φ+3137φ4(2.1839)\frac {3 \varphi + 3 \sqrt{13 - 7\varphi}}4 (\approx 2.1839)-competitive. Besides, we use Yao's principle to prove lower bounds of 1.66821.6682 and 1.65221.6522 on the expected competitive ratio for any randomized algorithm at the presence of at least three machines and only two machines, respectively, and prove a lower bound of 2.21172.2117 on the competitive ratio for any deterministic algorithm when there are only two machines.Comment: 21 pages with 1 plot; an extended abstract to be submitte

    Neutron Energy Spectrum Measurements with a Compact Liquid Scintillation Detector on EAST

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    A neutron detector based on EJ301 liquid scintillator has been employed at EAST to measure the neutron energy spectrum for D-D fusion plasma. The detector was carefully characterized in different quasi-monoenergetic neutron fields generated by a 4.5 MV Van de Graaff accelerator. In recent experimental campaigns, due to the low neutron yield at EAST, a new shielding device was designed and located as close as possible to the tokamak to enhance the count rate of the spectrometer. The fluence of neutrons and gamma-rays was measured with the liquid neutron spectrometer and was consistent with 3He proportional counter and NaI (Tl) gamma-ray spectrometer measurements. Plasma ion temperature values were deduced from the neutron spectrum in discharges with lower hybrid wave injection and ion cyclotron resonance heating. Scattered neutron spectra were simulated by the Monte Carlo transport Code, and they were well verified by the pulse height measurements at low energies.Comment: 19 pages,10 figures, 1 tabl

    Determination, source analysis and preliminary risk assessment of benzoic acid in rice wine

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    Objective To analyze the concentration and source of benzoic acid in rice wine and evaluate the health risk of dietary benzoic acid intake from rice wine among adult consumers in China. Methods 231 samples of rice wine and 15 samples of raw materials were collected from five main rice wine production areas in China, including Shandong, Zhejiang, Jiangsu, Fujian and Shanghai; the content of benzoic acid and its precursors were determined by high performance liquid chromatography; the sources of benzoic acid in rice wine were analyzed by the benzaldehyde and phenylalanine simulation test and the real sample acceleration test; the benzoic acid intake among adult consumers was evaluated by simple distribution assessment method. Results In all rice wine samples, the detection rate of benzoic acid was 99.13% (229/231), the concentration range of benzoic acid was ND (not detectable) -37.00 mg/L, and the average was 2.28 mg/L. In 98 end products, the detection rate of benzoic acid was 100.00% (98/98), the concentration range of benzoic acid was ND-1.60 mg/L, and the average was 0.52 mg/L; in 133 base wine samples, the detection rate of benzoic acid was 98.50% (131/133), the content range of benzoic acid was ND-37.00 mg/L, and the average was 3.58 mg/L. The result of source analysis showed that the benzoic acid in rice wine mainly came from raw materials, degradation of phenylalanine and oxidation of benzaldehyde. Exposure assessment result showed that the average exposure of benzoic acid for rice wine consumers in China was 0.001 mg/kg BW, accounting for 0.02% of the acceptable daily intake (ADI); and the 95th percentile was 0.005 mg/kg BW, accounting for 0.1% of the ADI. Conclusion The detection rate of benzoic acid in rice wine was high but the concentration was low. Source analysis result indicated that benzoic acid in rice wine mainly came from raw materials, degradation of phenylalanine and oxidation of benzaldehyde; the health risk of benzoic acid exposure to adult rice wine consumers in China was low

    Divergence of a genomic island leads to the evolution of melanization in a halophyte root fungus

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    AbstractUnderstanding how organisms adapt to extreme living conditions is central to evolutionary biology. Dark septate endophytes (DSEs) constitute an important component of the root mycobiome and they are often able to alleviate host abiotic stresses. Here, we investigated the molecular mechanisms underlying the beneficial association between the DSE Laburnicola rhizohalophila and its host, the native halophyte Suaeda salsa, using population genomics. Based on genome-wide Fst (pairwise fixation index) and Vst analyses, which compared the variance in allele frequencies of single-nucleotide polymorphisms (SNPs) and copy number variants (CNVs), respectively, we found a high level of genetic differentiation between two populations. CNV patterns revealed population-specific expansions and contractions. Interestingly, we identified a ~20 kbp genomic island of high divergence with a strong sign of positive selection. This region contains a melanin-biosynthetic polyketide synthase gene cluster linked to six additional genes likely involved in biosynthesis, membrane trafficking, regulation, and localization of melanin. Differences in growth yield and melanin biosynthesis between the two populations grown under 2% NaCl stress suggested that this genomic island contributes to the observed differences in melanin accumulation. Our findings provide a better understanding of the genetic and evolutionary mechanisms underlying the adaptation to saline conditions of the L. rhizohalophila–S. salsa symbiosis.</jats:p

    DNA self-assembly nanoflower reverse P-glycoprotein mediated drug resistance in chronic myelogenous leukemia therapy

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    Introduction: Chronic myelogenous leukemia (CML) is a clonal myeloproliferative disorder caused by the BCR-ABL chimeric tyrosine kinase. Vincristine (VCR) is widely used in leukemia therapy but is hindered by multidrug resistance (MDR).Methods: We prepared DNA nanoflower via self-assembly for the delivery of VCR and P-glycoprotein small interfering RNA (P-gp siRNA).Results and Discussion: The as-prepared nanoflower had a floriform shape with high loading efficiency of VCR (80%). Furthermore, the nanoflower could deliver VCR and P-gp siRNA into MDR CML cells and induce potent cytotoxicity both in vitro and in vivo, thus overcoming MDR of CML. Overall, this nanoflower is a promising tool for resistant CML therapy