检索结果-南通市图书馆

放电等离子超快速烧结SiC-Al_2O_3纳米复相陶瓷

在线全文

学校读者我要写书评

暂无评论

无机材料学报 1999年第1期14卷 55-60页

作者：高濂王宏志洪金生宫本大树 DiAZ de la torre SEBASTiAN 中国科学院上海硅酸盐研究所高性能陶瓷和超微结构国家重点实验室上海200050 日本大阪府立产业技术综合研究所

本文介绍用非均相沉淀法制备的纳米SiC－Al2O3复合粉体经放电等离子超快速烧结得到晶内型的纳米复相陶瓷，超快速烧结的升温速率为600℃／min，在烧结温度不保温，迅即在3min内冷却至600℃以下．与热压烧结相比，可降低烧结温度200℃以... 详细信息

本文介绍用非均相沉淀法制备的纳米SiC－Al2O3复合粉体经放电等离子超快速烧结得到晶内型的纳米复相陶瓷，超快速烧结的升温速率为600℃／min，在烧结温度不保温，迅即在3min内冷却至600℃以下．与热压烧结相比，可降低烧结温度200℃以上．力学性能研究结果表明，在1450℃超快速烧结得到的纳米复相陶瓷的抗弯强度高达1000MPa，维氏硬度为19GPa，断裂韧性也比Al2O3有所提高．TEM像显示纳米SiC颗粒大多分布在Al2O3母体晶粒内，而断裂表面的SEM像表明，穿晶断裂是其主要的断裂模式，这是所制备的纳米复相陶瓷力学性能大幅提高的主要原因．

关键词：碳化硅施电等离子烧结纳米粉体复合陶瓷

Genotoxicity evaluation of two derived products from Allium extracts: s-propylmercaptocysteine and s-propyl mercaptoglutathione

在线全文

学校读者我要写书评

暂无评论

FOOD BiOSCiENCE 2023年第3期53卷 1603-1611页

作者： Cascajosa-Lira, Antonio Medrano-Padial, Concepcion Prieto, Ana isabel Banos, Alberto de la torre, Jose M. Jos, Angeles Camean, Ana M. Univ Seville Fac Farm Area Toxicol Prof Garcia Gonzalez 2 Seville 41012 Spain DMC Res Ctr Camino Jayena 82 Alhendin 18620 Spain

Propyl-propane-thiosulfonate (PTSO) is one of the main organosulfur compounds present in Allium essential oils with a widely documented biological activity. For this reason, it could be used as a food and feed additive in the agri-food industry. A genotoxicity evaluation of substances and their metabolites present in food is necessary to guarantee the consumer's health following the recommendations of the European Food Safety Authority (EFSA). To evaluate the toxicological profile of derivatives of PTSO, the cytotoxicity, an Ames test, a micronucleus test and the comet assay were performed. Results showed that non-cytotoxic effects were observed in Caco-2 exposed to s-propyl mercaptocysteine (CSSP) and s-propyl mercaptoglutathione (GSSP) (0-450 mu M). The mutagenicity index remained in the range of 0.6-1.4 for both compounds, showing no mutagenic effects for the concentrations of 5000-312.5 mu g GSSP/plate and 250-15.63 mu g CSSP/plate. Moreover, the % binucleated cells with micronuclei were 1.3-2.2 and 1.6-2.7 for GSSP and GSSP, respectively. For comet assays there was no DNA-genotoxic or oxidative damage in a concentration range of 112.5-450 mu M. Therefore, we can conclude that these compounds are not genotoxic at the conditions tested. These results support that the presence of CSSP and GSSP in the food/ feed is not of concern, although further studies are needed to complete their safety profile.

关键词： Cytotoxicity Genotoxicity Mutagenicity Organosulfur compounds Allium Propyl-propane-thiosulfonate

Fabrication of Gypsum Panels with Low-Cost Alternative Materials

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Geological Resource and Engineering 2018年第1期6卷 19-24页

作者： Jose de la torre Luis Tapia Ernesto de la Torte Sebastian Gamez Modular Q Quito 170102 Ecuador department of Extractive Metallurgy Escuela Politdenica Nacional Ladr6n de Guevara E11-253 Quito Ecuador

During decades, gypsum has been employed as construction material for its versatility and particle size. in the present work, the possibility of developing gypsum panels with the incorporation of pumice and polypropylene as alternative materials has been investigated. Pumice as well as polypropylene allows obtaining lighter panels than those on the market and with a lower production cost. Each one of these materials was characterized separately. in the case of gypsum and pumice, their granulometry, pH and humidity were determined, whereas polypropylene was characterized by a traction-deformation essay. Then, panels composition （gypsum and pumice concentration）, particle size, water temperature and the way polypropylene was added, was assessed. Panels with a 70% of gypsum, with a particle size of 198 btm and with polypropylene added in a laminar fashion, presented a compressive strength of 350 kPa, which accords to the norm ASTM 1396 and with market requirements. Finally, it was proposed a block diagram of the process for the fabrication of 100 kg/day of formulated panels.

关键词： Panels gypsum pumice polypropylene.

Gelatin methacryloyl granular scaffolds for localized mRNA delivery

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Aggregate

Aggregate 2024年第2期5卷 386-400页

作者： Bruna Gregatti Carvalho Aya Nakayama Hiromi Miwa SangWon Han Lucimara Gaziola de la torre Dino Di Carlo Junmin Lee Han-Jun Kim Ali Khademhosseini Natan Roberto de Barros Terasaki institute for Biomedical innovation(TiBi) Los AngelesCaliforniaUSA department of Materials and Bioprocess Engineering School of Chemical EngineeringUniversity of Campinas(UNICAMP)CampinasBrazil department of Bioengineering University of California at Los Angeles(UCLA)Los AngelesCaliforniaUSA department of Biophysics Paulista School of MedicineFederal University of São Paulo(UNIFESP)CampinasBrazil department of Materials Science and Engineering Pohang University of Science and Technology(POSTECH)PohangRepublic of Korea institute for Convergence Research and Education in Advanced Technology Yonsei UniversityIncheonRepublic of Korea College of Pharmacy Korea UniversityPohangRepublic of Korea Centre for Biomaterials Cellular and Molecular Theranostics(CBCMT)Vellore Institute of Technology(VIT)VelloreIndia

Messenger RNA(mRNA)therapy is the intracellular delivery of mRNA to produce desired therapeutic *** strategies for local mRNA delivery is still required where direct intra-articular injections are inappropriate for targeting a specific *** mRNA delivery efficiency depends on protecting nucleic acids against nuclease-mediated degradation and safe site-specific intracellular ***,novel mRNA-releasing matrices based on RGD-moiety-rich gelatin methacryloyl(GelMA)microporous annealed particle(MAP)scaffolds are *** concentration in aerogel-based microgels(μgels)produced through a microfluidic process,MAP stiffnesses,and microporosity are crucial parameters for cell adhesion,spreading,and *** being loaded with mRNA complexes,MAP scaffolds composed of 10%GelMAμgels display excellent cell viability with increasing cell infiltration,adhesion,proliferation,and gene *** intracellular delivery is achieved by the sustained release of mRNA complexes from MAP scaffolds and cell adhesion on mRNA-releasing *** findings highlight that hybrid systems can achieve efficient protein expression by delivering mRNA complexes,making them promising mRNA-releasing biomaterials for tissue engineering.

关键词： GelMA lipid-based nanocarriers MAP scaffolds microfluidics mRNA

Recovery of Gold, Silver, Copper and Niobium from Printed Circuit Boards Using Leaching Column Technique

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Earth Science and Engineering 2012年第10期2卷 590-595页

作者： Ricardo Montero Alicia Guevara Ernesto de la torre Faculty of Chemical Engineering and Agro-industry Extractive Metallurgy Department National Polytechnic University Quito17012759 Ecuador

Nowadays, over 300 tons of Au are used in electronic equipment each year with other precious and strategic metals such as Ag, Pt, Pd, Cu, Nb, Ta, etc.. After the use-phase, the electronic devices become electronic waste （e-waste）; consequently it is important to consider e-waste as a secondary supply for the recovery of these metals. This paper presents the recovery ofAu, Ag, Cu and Nb from PCBs （printed circuit boards） of discarded computers using leaching column technique. The PCBs were crushed with a hammer mill until reaching a particle size between 3.33 mm to 0.43 mm, Then, it was leached with a sodium cyanide solution in a glass column using the following conditions： sodium cyanide concentration 4 g/L, flux 20 L/d kg PCBs day, pH between 10.5 to 11 and leaching time 15 days. Every day, after leaching, the pregnant solutions passed through a column with activated carbon to complete the closed loop system. The following recoveries were obtained： Au 46.6%, Ag 51.3%, Nb 47.2% and Cu 62.3%. A preliminary technical-economic study shows the feasibility to create a small-scale PCBs recycling plant. The initial investment is on the order of USS155,639, considering the recovered metals from the loaded carbon. The internal rate of return for a 10 years period iRR （internal rate of return） and NPV （net present value） estimated are 27% and US$105,926 respectively.

关键词： Printed circuit boards recovery precious metals niobium.

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

中国早期人类分布的环境制约因素探讨

第四纪研究 2021年第5期41卷 1342-1356页

作者：丁馨杜雨薇徐欣裴树文 de la torre ignacio 高星英国伦敦大学学院考古研究所英国伦敦WC1H 0PY 中国科学院脊椎动物演化与人类起源重点实验室中国科学院古脊椎动物与古人类研究所机构北京100044 中国科学院机构生物演化与环境卓越创新中心北京100044 西班牙国家研究委员会历史研究所西班牙马德里28037 中国科学院大学机构北京100049

在环境因素起制约作用的背景下,随着中国古人类演化与生存能力的进步,其数量和空间分布在不同时间段呈现出不同的特征。为了更好地了解中国早期人类的时空分布特征,本研究以中国境内已发表的2110处旧石器遗址的坐标和年代信息为基础,采... 详细信息

在环境因素起制约作用的背景下,随着中国古人类演化与生存能力的进步,其数量和空间分布在不同时间段呈现出不同的特征。为了更好地了解中国早期人类的时空分布特征,本研究以中国境内已发表的2110处旧石器遗址的坐标和年代信息为基础,采用统计学和空间分析的方法,对遗址的时间分布进行以蒙特卡洛模拟为基础的时间不定性模拟,对遗址的空间分布进行核密度估计和聚类分析;同时,利用环境空间数据集中的海拔、水源、气温和降水信息,对不同时期内各个遗址所在地的环境条件进行统计分析。研究结果表明,在旧石器时代,随着时间的发展,中国境内的遗址数量不断增多,分布范围也逐渐从中部、南部和东部地区向条件较恶劣的北部和西部扩张。其中,600 ka和57 ka为这一变化的两个关键时间点,600 ka之前遗址数量较少,分布也较为局限;在600 ka至57 ka之间,遗址数量缓慢增加,分布范围也在季风区内逐渐扩大;57 ka之后,遗址数量迅速增长,分布遍布中国境内的大部分地区。本文所梳理的中国境内旧石器遗址整体时空分布特征,为进一步解读中国早期人类的环境适应能力,特别是古人类的体质演化和技术进步的环境驱动机制提供参考。

关键词：古人类分布环境因素空间分析统计分析中国

Effect of the sintering technique on the ferroelectric and d33 piezoelectric coefficients of Bi0.5(Na0.84K0.16)0.5TiO3 ceramic

在线全文

学校读者我要写书评

暂无评论

Journal of Advanced Ceramics 2019年第2期8卷 278-288页

作者： G.HERNANdeZ-CUEVAS J.R.LEYVA MENDOZA P.E.GARCíA-CASiLlaS C.A.RODRíGUEZ GONZáLEZ J.F.HERNANdeZ-PAZ G.HERRERA-Pérez L.FUENTES-COBAS S.DíAZ de la torre O.RAYMOND-HERRERA H.CAMACHO-MONTES instituto de ingeniería y Tecnología Universidad Autónoma de Ciudad JuárezAv.Del Charro 450 Norte Cd.JuárezChihuahua32310México Centro de investigación en Materiales Avanzados Miguel de Cervantes 120Chihuahua 31109ChihuahuaMéxico Centro de investigación e innovación Tecnológica Instituto Politécnico NacionalCerrada de Cecati s/nAzcapotzalcoSanta Catarina02250Ciudad de MéxicoMéxico Centro de Nanociencias y Nanotecnología Universidad Nacional Autónoma de MéxicoKm.107 Carretera Tijuana-EnsenadaAP.14Ensenada 22860Baja CaliforniaMéxico

in the search of lead-free piezoelectric materials,ceramic processing techniques offer potential tools to increase the piezoelectric and ferroelectric properties in addition to new chemical *** of pure BNKT16(Bi0.5(Na0.84K0.16)0.5TiO3)phase were synthesized by sol–gel method with a low crystallization temperature(750℃).Ceramic samples were sintered by pressureless sintering(PLS),sinter-forging(SF),and spark plasma sintering(SPS)***,morphological,and chemical characterizations were performed by XRD,raman,EDS,and *** samples by PLS and SF exhibit rod-like grains associated to bismuth *** highest remanent polarization(11.05μC/cm2),coercive field(26.2 kV/mm),and piezoelectric coefficient(165 pC/N)were obtained for SF *** piezoresponse force microscopy(PFM)analysis shows that the crystallites at the nanoscale exhibit piezoelectric phenomenon and the highest piezoelectric response is reported for PLS *** presence of the rhombohedral phase,the increase in grain and crystallite size,and the oriented rod-like inclusions favoring the crystallographic texture are facts that enhance the piezoelectric coefficient for BNKT16 piezoceramics.

关键词： lead-free piezoelectrics sol–gel pressureless sintering (PLS) sinter-forging (SF) spark plasma sintering(SPS) piezoresponse

Evidence based medicine and surgical approaches for colon cancer: Evidences, benefits and limitations of the laparoscopic vs open resection

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2014年第13期20卷 3680-3692页

作者： laura Lorenzon Marco la torre Vincenzo Ziparo Francesco Montebelli Paolo Mercantini Genoveffa Balducci Mario Ferri department of Translational Medicine Sant’Andrea HospitalFaculty of Medicine and Psychology University of Rome "La Sapienza"00189 RomeItaly

AiM: To report a meta-analysis of the studies that compared the laparoscopic with the open approach for colon cancer resection.

关键词： laparoscopy Colon resection Colon cancer Meta-analysis Evidence-based medicine

High prevalence of viable Mycobacterium avium subspecies paratuberculosis in Crohn's disease

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2010年第36期16卷 4558-4563页

作者： Juan L Mendoza Amparo San-Pedro Esther Culebras Raquel Cíes Carlos Taxonera Raquel lana Elena Urcelay Fernando de la torre Juan J Picazo Manuel Díaz-Rubio department of Gastroenterology Hospital Clinico San Carlos28040 MadridSpain department of Clinical Microbiology Hospital Clinico San Carlos28040 MadridSpain department of internal Medicine Hospital Clinico San Carlos28040 MadridSpain department of immunology Hospital Clinico San Carlos28040 MadridSpain

AiM:To examine the detection rate of viable Mycobacterium avium subspecies paratuberculosis(MAP) in patients with inflammatory bowel disease [Crohn's disease(CD) and ulcerative colitis(UC)].METHODS:Thirty patients with CD(15 with at least one NOD2/CARD15 mutation),29 with UC,and 10 with no inflammatory bowel disease(iBD).were tested for MAP by polymerase chain reaction(specific iS900 fragment) and blood ***:MAP DNA was detected in all original blood samples and 8-wk blood cultures(CD,UC and non-iBD).Positive MAP DNA status was confirmed by dot blot *** 69 cultures were negative by acid-fast Ziehl-Neelsen *** MAP,in spheroplast form,was isolated from the 18-mo blood cultures of all 30 CD patients,one UC patient,and none of the non-iBD *** association was found between positive MAP cultures and use of immunosuppressive drugs or CDassociated single nucleotide ***:MAP is widely present in our area and MAP DNA can be recovered from the blood of CD,UC and non-iBD ***,MAP spheroplasts were only found in CD patients.

关键词： Mycobacterium avium subspecies paratuberculosis Crohn’s disease Ulcerative colitis inflammatory bowel disease Polymerase chain reaction Genetic susceptibility