6,305 research outputs found

    Evolution of pore structure, submaceral composition and produced gases of two Chinese coals during thermal treatment

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    This research was funded by the Research Program for Excellent Doctoral Dissertation Supervisor of Beijing (grant no. YB20101141501), the Fundamental Research Funds for Central Universities (grant no. 35832015136) and Key Project of Coal-based Science and Technology in Shanxi Province-CBM accumulation model and reservoir evaluation in Shanxi province (grant no. MQ2014-01).Peer reviewedPostprin

    1-Metilciklopropen ublažava oštećenja mahuna tijekom skladištenja pri niskim temperaturama povećanjem učinka antioksidacijskog sustava stanične zaštite

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    Research background. Chilling injury is a major disorder affecting the quality of tropical and subtropical vegetables during low temperature storage. Snap bean (Phaseolus vulgaris L.) is sensitive to chilling injury. The main purpose of the present study is to investigate the alleviating effects of 1-methylcyclopropene (1-MCP) on chilling injury of snap bean. In addition, the related mechanisms were also detected from the perspective of the changes of antioxidant defense system. Experimental approach. Snap beans were exposed to different volume fractions of 1-MCP. After 24 h of treatment, snap beans were stored at 4 °C for up to 14 days. Chilling injury index, electrolyte leakage, titratable acidity and total soluble solids were determined. Contents of chlorophyll, ascorbic acid and malondialdehyde were assessed. The total antioxidant capacity, Fe(II) ion chelating capacity, scavenging capacities on free radicals and activities of antioxidant enzymes were detected. Total phenol content and activities of related metabolic enzymes were also determined. Results and conclusions. 1-MCP treatment reduced chilling injury index, electrolyte leakage rate and malondialdehyde content of snap beans. The amounts of total soluble solids, titratable acid, ascorbic acid and total chlorophyll in 1-MCP-treated snap beans were significantly higher than those of control. The snap beans treated with 1-MCP showed stronger total antioxidant capacity and metal chelating activity. The 1-MCP treatment enhanced scavenging effects of snap beans on superoxide, hydroxyl and 1,1-diphenyl-2-trinitrophenylhydrazine radicals. The activities of peroxidase, ascorbate peroxidase, superoxide dismutase and catalase in 1-MCP-treated group were higher than of control. The treatment also enhanced the accumulation of phenolic compounds in snap beans by regulating the activities of phenol-metabolizing enzymes such as shikimate dehydrogenase, phenylalanine ammonia lyase enzyme, cinnamic acid 4-hydroxylase and polyphenol oxidase. In conclusion, with the mechanism that involves the activation of enzymatic and non-enzymatic antioxidant systems, 1-MCP has the ability to avoid chilling injury of snap bean. Novelty and scientific contribution. This study gives insights into whether 1-MCP can regulate postharvest cold resistance in vegetables by enhancing the enzymatic antioxidant system and inducing the accumulation of non-enzymatic antioxidants. Considering the results, 1-MCP treatment could be an effective method to alleviate postharvest chilling injury of snap beans during low temperature storage.Pozadina istraživanja. Oštećenje ploda tijekom skladištenja pri niskim temperaturama jedan je od primarnih uzroka smanjenja kakvoće tropskog i suptropskog povrća. Grah (Phaseolus vulgaris L.) je osjetljiv na oštećenja pri niskim temperaturama. Stoga je glavna svrha ovoga rada bila ispitati ublažavajući učinak 1-metilciklopropena na oštećenja mahuna pri niskim temperaturama. Osim toga, utvrđeni su mehanizmi promjene obrambenog antioksidacijskog sustava. Eksperimentalni pristup. Mahune su izložene različitim volumnim udjelima 1-metilciklopropena tijekom 24 sata. Nakon toga su uzorci mahuna skladišteni pri 4 °C do 14 dana. Mjereni su sljedeći parametri: indeks oštećenja pri niskim temperaturama, gubitak elektrolita, titracijska kiselost i udjel ukupnih topljivih tvari. Osim toga, utvrđeni su udjeli klorofila, askorbinske kiseline i malondialdehida. Određeni su ukupni antioksidacijski učinak, sposobnost keliranja Fe(II) iona, sposobnost uklanjanja reaktivnih kisikovih spojeva i aktivnost antioksidacijskih enzima. Također su određeni ukupni udjel fenola i s njima povezana metabolička aktivnost enzima. Rezultati i zaključci. Nakon obrade 1-metilciklopropenom smanjili su se indeks oštećenja pri niskim temperaturama, gubitak elektrolita i udjel malondialdehida u mahunama. Količine ukupnih topljivih suhih tvari, titracijske kiselosti, askorbinske kiseline i ukupnog klorofila u mahunama izloženim 1-metilciklopropenu bile su znatno veće nego u kontrolnom uzorku. Tretirane mahune imale su veću ukupnu antioksidacijsku aktivnost i sposobnost keliranja metala. Obradom 1-metilciklopropenom povećala se sposobnost uklanjanja radikala superoksida, hidroksila i 1,1-difenil-2-trinitrofenilhidrazina u mahunama. Aktivnosti peroksidaze, askorbat peroksidaze, superoksid dismutaze i katalaze bile su veće u tretiranim nego u kontrolnim uzorcima. Osim toga, obradom se povećalo nakupljanje fenolnih spojeva zbog regulacije enzima koji sudjeluju u metabolizmu fenola, kao što su šikimat-dehidrogenaza, fenilalanin amonijak-liaza, p-kumarinska kiselina i polifenol-oksidaza. Možemo zaključiti da 1-metilciklopropen može spriječiti oštećenje mahuna pri niskim temperaturama aktivacijom enzimskih i neenzimskih antioksidacijskih sustava. Novina i znanstveni doprinos. Ovaj rad daje uvid u mogućnost regulacije otpornosti povrća na niske temperature tijekom skladištenja poboljšanjem enzimskog antioksidacijskog sustava pomoću 1-metilciklopropena te nakupljanjem neenzimskih antioksidanasa. Dobiveni rezultati pokazuju da bi obrada 1-metilciklopropenom mogla biti učinkovita metoda ublažavanja oštećenja pri niskim temperaturama tijekom skladištenja graha

    Multiobjective evolutionary algorithm based on vector angle neighborhood

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    Selection is a major driving force behind evolution and is a key feature of multiobjective evolutionary algorithms. Selection aims at promoting the survival and reproduction of individuals that are most fitted to a given environment. In the presence of multiple objectives, major challenges faced by this operator come from the need to address both the population convergence and diversity, which are conflicting to a certain extent. This paper proposes a new selection scheme for evolutionary multiobjective optimization. Its distinctive feature is a similarity measure for estimating the population diversity, which is based on the angle between the objective vectors. The smaller the angle, the more similar individuals. The concept of similarity is exploited during the mating by defining the neighborhood and the replacement by determining the most crowded region where the worst individual is identified. The latter is performed on the basis of a convergence measure that plays a major role in guiding the population towards the Pareto optimal front. The proposed algorithm is intended to exploit strengths of decomposition-based approaches in promoting diversity among the population while reducing the user's burden of specifying weight vectors before the search. The proposed approach is validated by computational experiments with state-of-the-art algorithms on problems with different characteristics. The obtained results indicate a highly competitive performance of the proposed approach. Significant advantages are revealed when dealing with problems posing substantial difficulties in keeping diversity, including many-objective problems. The relevance of the suggested similarity and convergence measures are shown. The validity of the approach is also demonstrated on engineering problems.This work was supported by the Portuguese Fundacao para a Ciencia e Tecnologia under grant PEst-C/CTM/LA0025/2013 (Projecto Estrategico - LA 25 - 2013-2014 - Strategic Project - LA 25 - 2013-2014).info:eu-repo/semantics/publishedVersio

    Serum soluble ST2 is associated with ER-positive breast cancer

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    BACKGROUND: ST2, a member of the interleukin (IL)-1receptor family, regulates Th1/Th2 immune responses in autoimmune and inflammatory conditions. However, the role of ST2 signaling in tumor growth and metastasis of breast cancers has not been investigated. This study investigated the possible role of soluble ST2 (sST2) in breast cancer. METHODS: The serum levels of IL-33, sST2, and vascular endothelial growth factor (VEGF) in 150 breast cancer patients and 90 healthy women were measured by enzyme-linked immunosorbent assay. Estrogen receptor(ER), progesterone receptor, human epithelial receptor (HER)-2, and cell cycle regulated protein Ki-67 were measured. Clinical stage, tumor size, lymph node metastasis, and histological type were also recorded. RESULTS: The serum levels of sST2, IL-33, and VEGF were significantly higher in breast cancer patients than in the control group (P < 0.05, each). Serum sST2 levels in ER-positive breast cancer patients were significantly associated with age, histological type, clinical stage, tumor size, and Ki-67 status (P < 0.05, each). Moreover, the serum levels of IL-33 and sST2 in breast cancers significantly correlated with VEGF levels (IL-33: r = 0.375, P < 0.0001; sST2: r = 0.164, P = 0.045). Serum levels of sST2, IL-33, and VEGF decreased after modified radical mastectomy in ER-positive breast cancers. Serum levels of IL-33, sST2, and VEGF and clinicopathological factors were not significantly correlated with disease-free survival and overall survival of ER-positive breast cancer women during follow-up. CONCLUSION: Serum sST2 levels in ER-positive breast cancer patients are significantly associated with factors that indicate poor prognosis

    5-p-Tolyl-1,2,3,3a-tetra­hydro­benzo[e]pyrrolo­[2,1-b][1,3]oxazepin-10(5H)-one

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    The structure of the title compound, C19H19NO2, contains a seven-membered ring, which is fused to one five- and one six-membered ring, and carries a tolyl substituent. The two benzene rings are oriented relative to each other at a dihedral angle of 86.90 (7)°. In the crystal, mol­ecules are linked by weak inter­molecular C—H⋯O hydrogen bonds

    Identification and drug metabolic characterization of four new CYP2C9 variants CYP2C9*72-*75 in the Chinese Han population

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    Cytochrome 2C9 (CYP2C9), one of the most important drug metabolic enzymes in the human hepatic P450 superfamily, is required for the metabolism of 15% of clinical drugs. Similar to other CYP2C family members, CYP2C9 gene has a high genetic polymorphism which can cause significant racial and inter-individual differences in drug metabolic activity. To better understand the genetic distribution pattern of CYP2C9 in the Chinese Han population, 931 individuals were recruited and used for the genotyping in this study. As a result, seven synonymous and 14 non-synonymous variations were identified, of which 4 missense variants were designated as new alleles CYP2C9*72, *73, *74 and *75, resulting in the amino acid substitutions of A149V, R150C, Q214H and N418T, respectively. When expressed in insect cell microsomes, all four variants exhibited comparable protein expression levels to that of the wild-type CYP2C9 enzyme. However, drug metabolic activity analysis revealed that these variants exhibited significantly decreased catalytic activities toward three CYP2C9 specific probe drugs, as compared with that of the wild-type enzyme. These data indicate that the amino acid substitution in newly designated variants can cause reduced function of the enzyme and its clinical significance still needs further investigation in the future

    Experimental Quantum Hamiltonian Learning

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    Efficiently characterising quantum systems, verifying operations of quantum devices and validating underpinning physical models, are central challenges for the development of quantum technologies and for our continued understanding of foundational physics. Machine-learning enhanced by quantum simulators has been proposed as a route to improve the computational cost of performing these studies. Here we interface two different quantum systems through a classical channel - a silicon-photonics quantum simulator and an electron spin in a diamond nitrogen-vacancy centre - and use the former to learn the latter's Hamiltonian via Bayesian inference. We learn the salient Hamiltonian parameter with an uncertainty of approximately 10510^{-5}. Furthermore, an observed saturation in the learning algorithm suggests deficiencies in the underlying Hamiltonian model, which we exploit to further improve the model itself. We go on to implement an interactive version of the protocol and experimentally show its ability to characterise the operation of the quantum photonic device. This work demonstrates powerful new quantum-enhanced techniques for investigating foundational physical models and characterising quantum technologies

    Disparities and risks of sexually transmissible infections among men who have sex with men in China: a meta-analysis and data synthesis.

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    BACKGROUND: Sexually transmitted infections (STIs), including Hepatitis B and C virus, are emerging public health risks in China, especially among men who have sex with men (MSM). This study aims to assess the magnitude and risks of STIs among Chinese MSM. METHODS: Chinese and English peer-reviewed articles were searched in five electronic databases from January 2000 to February 2013. Pooled prevalence estimates for each STI infection were calculated using meta-analysis. Infection risks of STIs in MSM, HIV-positive MSM and male sex workers (MSW) were obtained. This review followed the PRISMA guidelines and was registered in PROSPERO. RESULTS: Eighty-eight articles (11 in English and 77 in Chinese) investigating 35,203 MSM in 28 provinces were included in this review. The prevalence levels of STIs among MSM were 6.3% (95% CI: 3.5-11.0%) for chlamydia, 1.5% (0.7-2.9%) for genital wart, 1.9% (1.3-2.7%) for gonorrhoea, 8.9% (7.8-10.2%) for hepatitis B (HBV), 1.2% (1.0-1.6%) for hepatitis C (HCV), 66.3% (57.4-74.1%) for human papillomavirus (HPV), 10.6% (6.2-17.6%) for herpes simplex virus (HSV-2) and 4.3% (3.2-5.8%) for Ureaplasma urealyticum. HIV-positive MSM have consistently higher odds of all these infections than the broader MSM population. As a subgroup of MSM, MSW were 2.5 (1.4-4.7), 5.7 (2.7-12.3), and 2.2 (1.4-3.7) times more likely to be infected with chlamydia, gonorrhoea and HCV than the broader MSM population, respectively. CONCLUSION: Prevalence levels of STIs among MSW were significantly higher than the broader MSM population. Co-infection of HIV and STIs were prevalent among Chinese MSM. Integration of HIV and STIs healthcare and surveillance systems is essential in providing effective HIV/STIs preventive measures and treatments. TRIAL REGISTRATION: PROSPERO NO: CRD42013003721
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