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Effect of homogenization process on the hardness of Zn-Al-Cu alloys

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International Journal of minerals,metallurgy and.materials 2015年第10期22卷 1076-1081页

作者： Jose d.Villegas-Cardenas maribel L.Saucedo-munoz Victor m.Lopez-Hirata Antonio de Ita-de la Torre Erika O.Avila-davila Jorge luis Gonzalez-Velazquez department of metallurgy and.materials Instituto Politecnico Nacional(IPN-ESIQIE)Mexico City 07300Mexico department of Industrial Engineering Universidad Politecnica del Valle de MexicoMexico CityMexico department of materials Universidad Autonoma Metropolitana(UAM)Unidad AzcapotzalcoMexico

The effect of a homogenizing treatment on the hardness of as-cast Zn–Al–Cu alloys was investigated. Eight alloy compositions were prepared and homogenized at 350 °C for 180 h, and their Rockwell 'B' hardness was subsequently measured. All the specimens were analyzed by X-ray diffraction and.metallographically prepared for observation by optical microscopy and scanning electron microscopy. The results of the present work indicated that the hardness of both alloys(as-cast and homogenized) increased with increasing Al and Cu contents; this increased hardness is likely related to the presence of the θ and τ′ phases. A regression equation was obtained to determine the hardness of the homogenized alloys as a function of their chemical composition and processing parameters, such as homogenization time and temperature, used in their preparation.

关键词： zinc–aluminum–copper alloys casting hardness homogenization phases microstructure

Use of two-surfactants mixtures to attain specific HLB values for assisted TPH-diesel biodegradation

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Journal of Environmental Sciences 2004年第6期16卷 950-956页

作者： luis G. Torres Neftalí Rojas Rosario Iturbe Instituto de Ingeniería Universidad Nacional Autó noma de México Coordinación de Ingeniería Ambiental Grupo Saneamiento de Suelos y Acuíferos Apartado Postal 70-472 Coyoacán 04510 México D.F. Mexico

In a surfactant assisted biodegradation process, the choice of surfactant(s) is of crucial importance. The question is: does the type of surfactant(i.e. chemical family) affect the biodegradation process at fixed hidrophillic-lypofillic balance(HLB) values? microcosm assessments were developed using contaminated soil, with around of 5000 mg/kg of hydrocarbons as TPH-diesel. mixtures of three nonionic surfactants were employed to get a wide range of specific HLB values. Tween20 and Span20 were mixed in the appropriate proportions to get HLB values between 8.6 and 16.7. Tween/Span60 mixtures reached HLB values between 4.7 and 14.9. Finally, Tween/Span80 combinations yielded HLB values between 4.3 and 15. TPH-diesel biodegradation was measured at the beginning, and after 8 weeks, as well as the FCU/gr soil, as a measure of microorganisms′ development during the biodegradation period. A second aim of this work was to assess the use of guar gum as a biodegradation enhancer instead of synthetic products. The conclusions of this work are that surfactant chemical family, and not only the HLB value clearly affects the assisted biodegradation rate. Surfactant's synergism was clearly observed. Regarding the use of guar gum, no biodegradation enhancement was observed for the three assessed concentrations, i.e., 2, 20, and 200 mg/kg, respectively. On the contrary, TPH-diesel removal was lower as the gum concentration increased. It is quite possible that guar gum was used as a microbial substrate.

关键词： aged soils enhanced bioremediation HLB mixtures Tween Span surfactants

Network analysis to inform invasive species spread among lakes

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Journal of Oceanology and Limnology 2019年第3期37卷 1037-1041页

作者： ESCOBAR luis E. ROmERO-ALVAREZ daniel LARKIN daniel J. PHELPS Nicholas B. d. department of Fish and Wildlife Conservation Virginia TechBlacksburgVirginiaUSA department of Ecology and Evolutionary Biology-Biodiversity Institute University of KansasLawrenceUSA department of Fisheries Wildlifeand Conservation BiologyUniversity of MinnesotaSt.PaulMinnesotaUSA minnesota Aquatic Invasive Species Research Center University of MinnesotaSt.PaulMinnesotaUSA

Often facilitated by human-mediated pathways,aquatic invasive species are a threat to the health and biodiversity of global *** present a novel approach incorporating survey data of watercraft movement in a social network analysis to reconstruct potential pathways of aquatic invasive species spread between *** an example,we use the green alga Nitellopsis obtusa,also known as starry stonewort,an aquatic invasive species affecting the Great Lakes region in the United States and *** movement of algal fragments via human-mediated pathways(i.e.,watercraft)has been hypothesized as the primary driver of starry stonewort *** used survey data collected at boat ramps during the 2013 and 2014 openwater seasons to describe the flow of watercraft from Lake Koronis,where *** was first detected in minnesota,to other lakes in the *** results suggest that the risk of *** expansion is not highly constrained by geographic proximity and.management efforts should consider highly connected *** human movement via network analysis may help to explain past and future routes of aquatic invasive species infestation between lakes and can improve evidence-based prevention and control efforts.

关键词： Nitellopsis obtusa starry stonewort lake network invasion

Preclinical evaluation of azathioprine plus buthionine sulfoximine in the treatment of human hepatocarcinoma and colon carcinoma

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World Journal of Gastroenterology 2011年第34期17卷 3899-3911页

作者： Borja Hernández-Breijo Jorge monserrat Sara Ramírez-Rubio Eva P Cuevas diana Vara Inés díaz-Laviada m dolores Fernández-moreno Irene d Román Javier P Gisbert luis G Guijarro molecular Hepatic Toxicology Unit Biochemistry and Molecular Biology Department University of Alcalá Networked Biomedical Research Center of Hepatic and Digestive Diseases (CIBEREHD) medicine department University of Alcalá Neuroendocrinology of Cannabinoid/Vanilloid System Unit Biochemistry and Molecular Biology Department University of Alcalá Gastroenterology Unit Hospital de la Princesa Institute of Health Research Princesa Networked Biomedical Research Center of Hepatic and Digestive Diseases (CIBEREHD)

AIm: To evaluate the efficacy and the safety of azathioprine (AZA) and buthionine sulfoximine (BSO) bylocalized application into HepG2 tumor in ***: different hepatoma and colon carcinoma cell lines (HepG2, HuH7, Chang liver, LoVo, RKO, SW-48, SW-480) were grown in minimal essencial medium supplemented with 10% fetal bovine serum and 1% antibiotic/antimycotic solution and.maintained in a humidified 37 ℃ incubator with 5% CO2. These cells were pretreated with BSO for 24 h and then with AZA for different times. We examined the effects of this combination on some proteins and on cellular death. We also studied the eff icacy and the safety of AZA (6 mg/kg per day) and BSO (90 mg/kg per day) in HepG2 tumor growth in vivo using athymic mice. We measured safety by serological markers such as aminotransferases and creatine ***: The in vitro studies revealed a new mechanism of action for the AZA plus BSO combination in the cancer cells compared with other thiopurines (6-mercaptopurine, 6-methylmercaptopurine, 6-thioguanine and 6-methylthioguanine) in combination with BSO. The cytotoxic effect of AZA plus BSO in HepG2 cells resulted from necroptosis induction in a mitochondrial-dependent manner. From kinetic studies we suggest that glutathione (GSH) depletion stimulates c-Jun amino-terminal kinase and Bax translocation in HepG2 cells with subsequent deregulation of mitochondria (cytochrome c release, loss of membrane potential), and proteolysis activation leading to loss of membrane integrity, release of lactate dehydrogenase and dNA degradation. Some of this biochemical and cellular changes could be reversed by N-acetylcysteine (a GSH replenisher). In vivo studies showed that HepG2 tumor growth was inhibited when AZA was combined with ***: Our studies suggest that a combination of AZA plus BSO could be useful for localizedtreatment of hepatocellular carcinoma as in the currently used transarterial chemoembolization method.

关键词： Azathioprine Buthionine sulfoximine Transarterial chemoembolization Glutathione Apoptosis Necrosis

Application of data science in the prediction of solar energy for the Amazon basin:a study case

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Clean Energy 2023年第6期7卷 1344-1355页

作者： Andréluis Ferreira marques márcio JoséTeixeira Felipe Valencia de Almeida Pedro Luiz Pizzigatti Corrêa Polytechnic School of the University of Sao Paulo Av.Prof.Luciano Gualberto380-ButantaSao Paulo-SP05508-010Brazil Institute of Physics of the University of Sao Paulo Brazil

The need for renewable energy sources has challenged.most countries to comply with environmental protection actions and to handle climate *** energy figures as a natural option,despite its *** has a green energy matrix with significant expansion of solar form in recent *** preserve the Amazon basin,the use of solar energy can help communities and cities improve their living standards without new hydroelectric units or even to burn biomass,avoiding harsh environmental *** novelty of this work is using data science with machine-learning tools to predict the solar incidence(W.h/m^(2))in four cities in Amazonas state(north-west Brazil),using data from NASA satellites within the period of ***-tree-based.models and vector autoregressive(time-series)models were used with three time aggregations:day,week and *** predictor model can aid in the economic assessment of solar energy in the Amazon basin and the use of satellite data was encouraged by the lack of data from ground *** mean absolute error was selected as the output indicator,with the lowest values obtained close to 0.20,from the adaptive boosting and light gradient boosting algorithms,in the same order of magnitude of similar references.

关键词： solar energy renewable energy Amazon basin machine learning time series data science decision-trees ensemble vector autoregression

Probiotics as Control Agents in Aquaculture

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Journal of Ocean University of China 2007年第1期6卷 76-79页

作者： Gómez R. Geovanny d Balcázar José luis mariculture Research Laboratory Ocean University of China Qingdao 266003 P. R.China Laboratory of Fish Pathology Faculty of Veterinary Medicine University of Zaragoza C /. Miguel Servet 177 Zaragoza 50013 Spain

Infectious diseases constitute a limiting factor in the development of the aquaculture production, and control has solely concentrated on the use of antibiotics. However, the massive use of antibiotics for the control of diseases has been questioned by acquisition of antibiotic resistance and the need of alternative is of prime importance. Probiotics, live microorganisms administered in adequate amounts that confer a healthy effect on the host, are emerging as significant microbial food supplements in the field of prophylaxis.

关键词： aquaculture diseases prevention probiotics

Benchmarking of two three-d.mensional numerical models in time/space d.main to predict railway-induced ground vibrations

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Earthquake Engineering and Engineering Vibration 2021年第1期20卷 245-256页

作者： Jesus Fernandez-Ruiz luis E.medina Rodriguez Pedro Alves Costa margarita martinez-diaz University of La Coruna Department of Civil EngineeringCampus de ElvinaLa Coruna 15071Spain University of Porto Faculty of EngineeringRua Dr.Roberto Friass/n Porto4200-465Portugal University of La Coruna Department of Naval and Industrial EngineeringCampus de ElvinaLa Coruna 15071Spain

In the last 30 years,the scientific community has developed and proposed different models and numerical approaches for the study of vibrations induced by railway *** of them are formulated in the frequency/wave number d.main and with a 2.5d ***-d.mensional numerical models formulated in the time/space d.main are less frequently used.mainly due to their high computational ***,these models present very attractive characteristics,such as the possibility of considering nonlinear behaviors or the modelling of excess pore pressure and non-homogeneous and non-periodic geometries in the longitudinal direction of the *** this study,two 3d numerical approaches formulated in the time/space d.main are compared and experimentally *** first one consists of a finite element approach and the second one of a finite difference *** experimental validation in an actual case situated in Carregado(Portugal)shows an acceptable fitting between the numerical results and the actual measurements for both ***,there are some differences among *** study therefore includes some recommendations for their use in practical soil dynamics and geotechnical engineering.

关键词： railway vibrations time/space d.main 3d numerical model finite difference method implicit finite element method

Calcium isotope fractionation and its controlling factors over authigenic carbonates in the cold seeps of the northern South China Sea

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Chinese Science Bulletin 2012年第11期57卷 1325-1332页

作者： WANG ShuHong YAN Wen mAGALHAES H Vitor CHEN Zhong PINHEIRO m luis GUSSONE Nikolaus CAS Key Laboratory of marginal Sea Geology South China Sea Institute of OceanologyChinese Academy of SciencesGuangzhou 510301China Centre for Environmental and.marine Studies(CESAm)and Geosciences department University of AveiroAveiro 3810-193Portugal Institut fiir mineralogie Universitgit MiinsterMiinster 48149Germany

In this study, we analyzed stable calcium isotope results of authigenic carbonates from two cold seep areas of the dongsha area and the Baiyun Sag in the northern South China Sea. The stable isotopes of carbon and oxygen as well as the mineral composition of authigenic carbonates were used to investigate control calcium isotope fractionation. The δ44/40Ca ratios of the southwestern dongsha area samples ranged from 1.21‰ to 1.52‰ and the ratio of the Baiyun Sag sample was 1.55‰ of the SRm915a isotope standard. X-ray diffraction analysis showed that the carbonate samples consisted of dolomite, calcite and aragonite, with small amounts of high-mg calcite and siderite. The δ13C values of the carbonates of the southwestern dongsha area varied between δ49.21‰ and δ16.86‰ of the Vienna Peedee Belemnite (VPdB) standard and the δ18O values ranged from 2.25‰ to 3.72‰ VPdB. The δ13C value of the Baiyun Sag sample was 2.36‰ VPdB and the δ18O value was 0.44‰ VPdB. The δ13C values of the carbonates of the southwestern dongsha area revealed there is methane seeping into this area, with a variable contribution of methane-derived carbon. The sampled carbonates covered a range of δ13C values suggesting a d.minant methane carbon source for the light samples and.mixtures of δ13C values for the heavier samples, with possibly an organic or seawater carbon source. The δ18O values indicated that there is enrichment in 18O, which is related to the larger oxygen isotope fractionation in dolomite compared to calcite. The results of the Baiyun Sag sample exhibited normal seawater carbon and oxygen isotopic values, indicating that this sample is not related to methane seepage but instead to precipitation from seawater. The relatively high δ44/40Ca values indicated either precipitation at comparatively high rates in pore-water regimes with high alkalinity, or precipitation from an evolved heavy fluid with high degrees of Ca consumption (Raleigh type fractionation). The dolomite samples from the

关键词：氧同位素分馏碳酸盐岩控制因素南海北部冷泉中国碳稳定同位素 X射线衍射分析

Outlining key inflammation-associated parameters during early phase of an experimental gram-negative sepsis model in rhesus macaques(macaca mulatta)

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Animal models and Experimental medicine 2019年第4期2卷 326-333页

作者： Jose J.Rosado-Franco marcos J.Ramos-Benitez Laura m.Parodi derick Rosario Nicole Compo luis d.Giavedoni Ana m.Espino department of microbiology and.medical Zoology Medical Sciences CampusUniversity of Puerto RicoSan JuanPuerto Rico Southwest National Primate Research Center Texas Biomedical Research InstituteSan AntonioTXUSA Chemistry department Rio Piedras CampusUniversity of Puerto RicoSan JuanPuerto Rico medical Sciences Campus Caribbean Primate Research Center University of Puerto RicoToa BajaPuerto Rico

The aim of this study was to identify inflammation-associated.markers during the early phase of sepsis in rhesus macaque. Four rhesus macaques were given an intravenous dose of 1010 CFU/kg of E. coli. Blood samples were collected before, or 30 minutes, 2, 4, 6 and 8 hours after E. coli infusion. Physiological parameters, bacteremia, endotoxemia, C-reactive protein(CRP), procalcitonin(PCT), and plasma cytokines/chemokines were determined for each animal. Bacteremia was present in all animals from 30 minutes to 3 hours after E. coli infusion whereas endotoxin was detected during the full-time course. CRP and PCT levels remained at detectable levels during the whole experimental window suggesting an ongoing inflammatory process. Signature cytokines and chemokines such as TNF-α, mIP-1α, and.mIP-1β peaked about 2 hours after E. coli infusion and decreased thereafter. Plasma IL-6, IL-12 p40, IFN-γ, and IL-1 Ra, as well as I-TAC, mIG, IP-10 and.mCP-1, remained at detectable levels after 4 hours of E. coli infusion. This nonhuman primate model could be useful for the assessment of new therapeutics aiming to suppress key inflammatory markers throughout sepsis early phases.

关键词： chemokines cytokines macaca mulatta sepsis