832 resultados para Cicerón, Marco-Tulio, 106-43 a.C.
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A doença falciforme é uma síndrome hematológica genética que faz parte das hemoglobinopatias de grande abrangência na população mundial. Estima-se que 4,5% da população apresente algum tipo de hemoglobinopatia, cujos aspectos clínicos oscilam de leve à grave. O principal fator que pode influenciar o fenótipo das doenças falciformes é o genótipo da doença; homozigose para HbS ou genótipos compostos do tipo HbSC, HbS/beta-talassemia, HbSD. Este pode desenvolver distúrbios como dislipidemia, colelitíase e transtornos cardiovasculares que podem causar o óbito. O presente estudo visa correlacionar o perfil lipídico de pacientes portadores de doença falciforme. Foram avaliados 52 pacientes do Serviço de Hematologia Clínica do Hospital Universitário Pedro Ernesto HUPE-UERJ, portadores da doença falciforme confirmada pela técnica de HPLC realizada no Laboratório de Análises Clínicas da Faculdade de Farmácia (LACFAR)-UFRJ. As análises hematológicas compostas pelo hemograma completo e dosagens bioquímicas do perfil lipídico formado pela dosagem de triglicerídeos, colesterol total, colesterol HDL, colesterol LDL e colesterol VLDL. A população estudada é composta por 52 pacientes, sendo 22 pacientes do sexo masculino, representando 42% do total de pacientes e 30 do sexo feminino, definindo 58% do total. E com objetivo comparativo, foi constituído um grupo controle de 52 pessoas com média de idade 26 anos, variando entre 5 e 63 anos. A população de Doença Falciforme apresenta grupos etários que oscilam entre 6 e 60 anos de idade, tendo média de 28 anos. Baseada nas características fenotípicas definidas por HPLC, a classificação de hemoglobina demonstra um grupo de 83% de portadores de Hemoglobina SS (n=43), 13% portadores de Hemoglobina SC (n=7) e 4% com Hemoglobina SB0 (n=2). Em relação às dosagens bioquímicas, a análise do perfil lipídico demonstra hipocolesterolemia, cuja média da população é definida por 122mg/dL quando comparada com o grupo controle (GC) com média de 201mg/dL (p<0,001). A taxa do colesterol-HDL situa-se na média de 29mg/dL e do GC 54 mg/dL (p<0,001) e do colesterol-LDL 69mg/dL enquanto o GC 120mg/dL (p<0,001). A sistematização dos resultados hematológicos define uma média de hematimetria de 2,7. 106/mm3. Na dosagem de hemoglobina obteve-se média de 8,4g/dL. Tais resultados caracterizam que é predominante neste grupo a hipocromia sem expressão de microcitose. Dentre os processos patológicos mais comuns, a litíase biliar se destacou nos pacientes com doença falciforme, onde 25% dos pacientes estudados (n=13) apresentaram este comprometimento hepatobiliar, na qual grande parte desses pacientes foram submetidos à colecistectomia. A doença Falciforme cursa com hiperplasia medular principalmente às custas da hiperproliferação dos precursores eritróides na medula óssea. O estado hiperproliferativo nessa doença possivelmente causa redução do colesterol plasmático para atender à maior demanda deste elemento para síntese de novas membranas. Esta redução na produção endógena de colesterol pode ser entendida pela disfunção hepática que habitualmente está presente em pessoas com doença falciforme. Logo se concluiu que existe uma correlação de hipocolesterolemia total e de HDL-c baixo em pacientes com doença falciforme.
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Aspartate aminotransferase (E.C. 2.6.1.1.) from the skeletal muscle of fresh water fish Cirrhina mrigala has been purified 40 fold by ammonium sulphate fractionation, adsorption on alumina Csub(8) gel and chromatography using DEAE-cellulose column and the properties of the purified enzyme studied. The pH optimum of the enzyme is 7.8. The Km value of aspartic acid and 2-oxoglutaric acid are found to be 2.8 x 10sub(-3) M and 1.0 x 10sub(-4) M respectively. The activity of enzyme is inhibited by p-chloromercurybenzoate, hydroxylamine hydrochloride and sodium cyanide. The inhibition by pchloromercurybenzoate is reversed by reduced glutathione, B-mercaptoethanol and cysteine. Dicarboxylic acids such as maleic acid, malic acid and succinic acid inhibit the enzyme activity. The enzyme is not activated by any of the metal ions tested and heavy metal ions such as mercury and silver strongly inhibit the enzyme activity.
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The southeastern region of Yunnan province is a key site for drug trafficking and HIV-1 infection spread from the west of Yunnan and Laos to southeastern China. To investigate the prevalence of HIV-1 infection and hepatitis C virus (HCV) coinfection among injection drug users (IDUs) in southeastern Yunnan, three cohorts of 285 addicts, including 242 IDUs and 43 oral drug users, living in the cities of Gejiu and Kaiyuan and the county of Yanshan were studied. HIV-1 and HCV infections were detected by enzyme-linked immunosorbent assay and/or polymerase chain reaction. Data on the age, sex, risk behavior, drug use history, employment, ethnic background, and marriage status were obtained by interview. The overall prevalence of HIV-1 infection was 71.9%. The rate of HCV coinfection among 138 HIV-1-infected IDUs was 99.3%. Most HIV-infected IDUs were 20 to 35 years old (86.7%) and were ethnic Han (75.9%), suggesting that the epidemic in Yunnan is no longer confined to non-Han ethnic minorities, HIV prevalence in female IDUs (81.2%) was significantly higher than in male IDUs (68.2%) (p <.05). The prevalence of HIV infection reached 68.4% after 1 year of injection drug use. Needle/syringe sharing is the major high risk factor for the spread of HIV-1 and HCV infections. Large-scale educational campaigns are urgently needed to reduce the spread of HIV and HCV infection in these regions.
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Thin films (100-500 nm) of the Si:O alloy have been systematically characterized in the optical absorption and electrical transport behavior, by varying the Si content from 43 up to 100 at. %. Magnetron sputtering or plasma enhanced chemical vapor deposition have been used for the Si:O alloy deposition, followed by annealing up to 1250 °C. Boron implantation (30 keV, 3-30× 1014 B/cm2) on selected samples was performed to vary the electrical sheet resistance measured by the four-point collinear probe method. Transmittance and reflectance spectra have been extracted and combined to estimate the absorption spectra and the optical band gap, by means of the Tauc analysis. Raman spectroscopy was also employed to follow the amorphous-crystalline (a-c) transition of the Si domains contained in the Si:O films. The optical absorption and the electrical transport of Si:O films can be continuously and independently modulated by acting on different parameters. The light absorption increases (by one decade) with the Si content in the 43-100 at. % range, determining an optical band gap which can be continuously modulated into the 2.6-1.6 eV range, respectively. The a-c phase transition in Si:O films, causing a significant reduction in the absorption coefficient, occurs at increasing temperatures (from 600 to 1100 °C) as the Si content decreases. The electrical resistivity of Si:O films can be varied among five decades, being essentially dominated by the number of Si grains and by the doping. Si:O alloys with Si content in the 60-90 at. % range (named oxygen rich silicon films), are proved to join an appealing optical gap with a viable conductivity, being a good candidate for increasing the conversion efficiency of thin-film photovoltaic cell. © 2010 American Institute of Physics.
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Fe films with the different thicknesses were grown on c(4x4) reconstructed GaAs (001) surfaces at low temperature by molecular-beam epitaxy. Well-ordered bcc structural Fe epitaxial films are confirmed by x-ray diffraction patterns and high-resolution cross-sectional transmission electron microscopy images. A large lattice expansion perpendicular to the surface in Fe film is observed. In-plane uniaxial magnetic anisotropy is determined by the difference between magnetizing energy along [110] and [110] directions, and the constant of interfacial uniaxial magnetic anisotropy is calculated to be 1.02x10(-4) J m(-2). We also find that magnetic anisotropy is not obviously influenced after in situ annealing, but in-plane strain is completely changed.
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Hydrogenated nanocrystalline silicon (nc-Si:H) n-layers have been used to prepare heterojunction solar cells on flat p-type crystalline silicon (c-Si) wafers. The nc-Si:H n-layers were deposited by radio-frequency (RF) plasma enhanced chemical vapor deposition (PECVD), and characterized using Raman spectroscopy, optical transmittance and activation energy of dark-conductivity. The nc-Si:H n-layers obtained comprise fine grained nanocrystallites embedded in amorphous matrix, which have a wider bandgap and a smaller activation energy. Heterojunction solar cells incorporated with the nc-Si n-layer were fabricated using configuration of Ag (100 nm)/1T0 (80 nm)/n-nc-Si:H (15 nm)/buffer a-Si:H/p-c-Si (300 mu m)/Al (200 nm), where a very thin intrinsic a-Si:H buffer layer was used to passivate the p-c-Si surface, followed by a hydrogen plasma treatment prior to the deposition of the thin nanocrystalline layer. The results show that heterojunction solar cells subjected to these surface treatments exhibit a remarkable increase in the efficiency, up to 14.1% on an area of 2.43 cm(2). (c) 2006 Elsevier B.V. All rights reserved.
Resumo:
Hydrogenated nanocrystalline silicon (nc-Si:H) n-layers have been used to prepare heterojunction solar cells on flat p-type crystalline silicon (c-Si) wafers. The nc-Si:H n-layers were deposited by radio-frequency (RF) plasma enhanced chemical vapor deposition (PECVD), and characterized using Raman spectroscopy, optical transmittance and activation energy of dark-conductivity. The nc-Si:H n-layers obtained comprise fine grained nanocrystallites embedded in amorphous matrix, which have a wider bandgap and a smaller activation energy. Heterojunction solar cells incorporated with the nc-Si n-layer were fabricated using configuration of Ag (100 nm)/1T0 (80 nm)/n-nc-Si:H (15 nm)/buffer a-Si:H/p-c-Si (300 mu m)/Al (200 nm), where a very thin intrinsic a-Si:H buffer layer was used to passivate the p-c-Si surface, followed by a hydrogen plasma treatment prior to the deposition of the thin nanocrystalline layer. The results show that heterojunction solar cells subjected to these surface treatments exhibit a remarkable increase in the efficiency, up to 14.1% on an area of 2.43 cm(2). (c) 2006 Elsevier B.V. All rights reserved.
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采用Cr/Al催化体系,成功地合成了全同1,2-聚丁二烯(PBD),并用DSC方法、X-射线衍射、红外光谱及~(13)C-NMR的方法进行结构与物性测定,得如下结果:全同1,2-PBD的熔点为124.3℃;三角晶系中,分子链成了螺旋,晶胞参数为a=17.3A,c= 6.5A;在红外光谱中,其特征谱带出现在694.4 cm~(-1)处;在~(13)C-NMR谱中仅出现四条谱峰,其化学位移分别为142.51、111.56、39.26、37.43 ppm。全同1,2-PBD的~(13)C-NMR谱提供的实验数据表明,在~(13)C-NMR谱中1,2-PBD-CH二碳十个五元组谱峰的归属是有别于Elgert、Kumar已有的归属。它属于一种新的归属,与半经验方法所推演的结果相符。它恰巧同聚丙烯侧甲基五元组谱峰的归属一致。采用半经验方法研究了1,2-PBD的~(13)C-NMR增中CH二碳五元组、CH_2-碳四元组及六元组共振谱峰,同时讨论了模型链的链长、温度以及立构序列的排列对各立构序列键概率的影响,求得了相应的r值。同时采用经验方法对1,2-PBD的~(13)C-NMR谱中CH_2=碳、CH-碳五元组及CH_2-碳四元组谱峰做了归属。两种方法对CH_2-碳谱峰的归属得到了一致的结果。
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目的构建HIV-1C亚型gp120负载人树突状细胞(dentriti ccell,DC)疫苗,并对其体外功能进行初步检测。方法利用Amaxa细胞核转染技术将pcDNA3.1-gp120质粒转染至人成熟DC,以Western blot检测gp120的表达。通过流式细胞仪检测DC表面共刺激分子的变化、混合淋巴细胞反应、CD8+T细胞表面活化分子CD25的表达及其分泌IFN-γ的变化。结果通过Western blot检测,gp120在DC中得到了正确表达。经流式细胞仪检测,DC表面分子CD80表达率由刺激前的33.34%上升至43.20%,CD86表达率由刺激前的60.08%上升至90.34%;负载gp120DC刺激淋巴细胞增殖率为86.72%;CD8+T细胞表面分子CD25表达率由刺激前的5.27%上升至74.21%,IFN-γ的表达率达37%。结论负载了HIV-1gp120的人树突状细胞能够显著刺激淋巴细胞的增殖、增强CD8+T细胞表面活化分子CD25表达以及促进CD8+T细胞分泌IFN-γ,为下一步DC治疗性疫苗的体内研究奠定基础。
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在长期的吸血进化过程中,吸血节肢动物在唾液腺中形成了一系列有助于适应吸 血生存的活性物质,这些物质包括血管舒张分子、血小板聚集抑制分子、抗凝血分子 和其它相互作用的分子。此外,为了得到洁净的血液和防止在吸血过程中被病原微生 物感染,吸血节肢动物在其唾液腺中形成了许多防御物质以保护自身和宿主,这些物 质包括抗菌肽和蛋白酶抑制剂等。因此,研究吸血节肢动物的唾液腺重要活性物质和 转录体组学有助于弄清其吸血机制。 姚虻(Tabancus yao Macquart)是我国特有的牛虻,其雌性在产卵前需要吸食大 型哺乳动物的血液以促使卵的发育。我们希望通过对姚虻唾液腺重要活性物质和转录 体组学的研究揭示姚虻成功从宿主获得血餐的分子机制,找到具有药用前景的活性物 质和为控制该虫及其传播的疾病的提供理论基础。 首先,我们对其唾液腺匀浆物活性进行了系统分析,发现姚虻唾液腺匀浆物具有 如下活性:有抗金黄色葡萄球菌活性,并且对大肠杆菌、白色念球菌和枯草杆菌都有 效;能够抑制ADP 诱导的洗涤和富血浆血小板的聚集;能够凝集兔红细胞、能够抑制 丝氨酸蛋白酶对小肽底物的水解、具有对纤维蛋白原的水解活性(金属蛋白酶)、具 有过敏原活性、能够促进肥大细胞脱粒和组氨释放;反复检测而没有发现的活性如下: 磷脂酶A2(PLA2)活性、溶血活性、血浆凝固活性、体外抗补体、血管生长促进与抑制 活性、对小鼠脾细胞因子分泌的促进和抑制活性、抗肿瘤细胞HepG2 的生长活性。 以来源姚虻唾液腺的mRNA为材料,我们成功构建了丰度为1x106的姚虻唾液腺 cDNA文库。通过对400个随机克隆的测序,我们得到了编码23种保守蛋白,44种分泌 蛋白和5种功能未知的蛋白。44种分泌蛋白中比较重要的分别是:20种抗原5相关蛋白、 2种α淀粉酶、2种麦芽糖酶、2种attactins抗菌蛋白以及血管舒张肽、过氧化物酶、 抗菌肽、透明质酸酶、mucin样蛋白和脯氨酸丰富蛋白。另外,一些不知道功能的分 泌肽也被发现,这其中包括四个与Hybomitra bimaculata的分泌肽相似性达47-82%的 多肽,这些信息有助于我们发现牛虻唾液腺活性物质和加快从知道部分氨基酸序列的 蛋白的鉴定速度,加快对姚虻从宿主获得血餐的分子机制的诠释速度。 通过分子筛、高压液相色谱等程序,我们从姚虻唾液腺中得到了一个由55 个氨 基酸组成,分子量为6 kDa,含有3 对二硫键的Kunitz 型丝氨基酸蛋白酶抑制剂TYTI。 该抑制剂与Anemonia sulcata 的蛋白酶抑制剂AsKC3 和SA5II 的成熟肽部分的同源 性达66%;并且该抑制剂,对热相对稳定;对凝乳酶、弹性蛋白酶、凝血酶、胰酶等 都有抑制作用,对胰酶的抑制常数为2.586x10-4M 。 通过分子筛、高压液相色谱等程序,我们从姚虻唾液腺中得到了一分子量为7 kDa,由65 个氨基酸组成且含有3 对二硫键的防御素Taymin,它与长角血蜱的防御素的相 似性达43%,但它的第二个半胱氨酸比长角血蜱的半胱氨酸靠前一个氨基酸。该抗菌 肽对大肠杆菌、金黄色葡萄球菌、枯草芽孢杆菌和白色念球菌的最小抑菌浓度分别是: 160、80、140 和120μg/mL。 通过与分离丝氨酸蛋白酶抑制剂相同的生化分离手段,从姚虻唾液腺中得到一种 红细胞凝集素样活性物质TYML1,其能凝集原始和经胰酶、链霉蛋白酶和弹性蛋白酶 处理的A、B、O 和AB 血型的人、兔、绵羊、大鼠、小鼠、鹌鹑的红细胞, 对链霉蛋 白酶处理的鹌鹑红细胞的凝集效价比正常下降了8 倍;对热、酸、碱处理和蛋白酶降 解稳定;具有Ca2+依赖性,活性能为半乳糖胺和胎球蛋白所完全抑制。 通过分子筛、阴离子交换、高压液相色谱等程序,我们从姚虻唾液腺中分离得到 了一分子量为26 kDa,由234 个氨基酸组成,含有10 个半胱氨酸的血小板聚集抑制剂 Macquaritin-2,它与报道的所有血小板聚集抑制剂均不具有同源性,但是与双翅目昆 虫唾液腺过敏原却有一定的同源性(25%-33%),对其血小板聚集抑制活性研究发现:其 能抑制胰酶、花生四烯酸、Stejnulxin、TMVA、ADP、U46619 等激动剂诱导的血小板 聚集;血小板膜结合试验表明:其能与血小板细胞膜结合,故该血小板聚集抑制剂可能 通过作用血小板上的受体来阻止激动剂诱导血小板聚集。 通过分子筛、阳离子交换、高压液相色谱等程序,我们从姚虻唾液腺中分离得到 分子量为24-30 kDa 的两个血小板聚集抑制剂Macquaritin-3 和Macquaritin-1,它 们的N 端16 个氨基酸分别是V N Y C R L P C R G C D Y H V 和 V A V D Y L G L P G R G Y H V。通过PCR, Macquaritin-3 的核苷酸序列被得到,其推导蛋白的成熟区 和信号肽分别含有232 和23 个氨基酸。利用根据Macquaritin-1 的N 端氨基酸设计 的简并引物扩到含有V A V D Y L G L P 序列的两组核苷酸序列。它们与报道的所有 血小板聚集抑制剂均不具有同源性,但是其与双翅目昆虫的唾液腺抗原5 相关蛋白却 有一定的同源性。将所有血小板抑制剂及其相关序列和通过cDNA 文库筛选得到的抗 原5 相关序列进行分析,发现它们有很高的相似性,这种相似性介于33.3%-93.0%间, 且大部分高于50%。另外,两个血小板聚集抑制剂和一个可能的血小板抑制剂分别处 于这些抗原5 相关蛋白进化树的三个簇中。因此,我们推测这些过抗原5 相关蛋白可 能都具有血小板抑制剂活性。
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The damage removal and strain relaxation in the As+-implanted Si0.57Ge0.43 epilayers were studied by double-crystal x-ray diffractometry and transmission electron microscopy. The results presented in this paper indicate that rapid thermal annealing at temperatures higher than 950 degrees C results in complete removal of irradiation damage accompained by the formation of GeAs precipitates which enhance the removal process of dislocations.