Mạng xã hội chia sẻ tài liệu
Báo cáo tổng kết luận văn
Luận án Tiến sĩ Khí tượng và khí hậu học: Biến đổi một số đặc trưng gió mùa mùa hè ở Tây Nguyên và Nam Bộ
Luận án đã xác định được ngày bắt đầu/ kết thúc gió mùa mùa hè (GMMH) và xu thế biến đổi của nó trong giai đoạn 1981-2014; chỉ ra sự khác biệt giữa mùa mưa và mùa GMMH; phân tích chỉ số mưa và đặc điểm một số trường quy mô lớn trong thời kỳ này; đánh giá sai số, hiệu chỉnh số liệu mưa và đánh giá khả năng mô phỏng gió mùa mùa hè bằng mô hình RegCM trong quá khứ... Mời các bạn cùng tham khảo nội dung chi tiết.139 trang
183 lượt xem
11 lượt tải
Báo cáo Y học: Presence and regulation of the endocannabinoid system in human dendritic cells
Cannabinoid receptors and their endogenous ligands, the endocannabinoids, have been detected in several blood immune cells, including monocytes/macrophages, basophils and lymphocytes. However, their presence in dendritic cells, which play a key role in the initiation and development of the immune response, has never been investigated. Here we have analyzed human dendritic cells for the presence of the endocannabinoids, anandamide and 2-arachidonoylglycerol (2-AG), the cannabinoid CB1 and CB2 receptors, and one of the enzymes mostly responsible for endocannabinoid hydrolysis, the fatty acid amide hydrolase (FAAH)....8 trang
112 lượt xem
4 lượt tải
Báo cáo Y học: N-myc oncogene overexpression down-regulates leukemia inhibitory factor in neuroblastoma
Amplification of N-myc oncogene is a frequent event in advanced stages of human neuroblastoma and correlates with poor prognosis and enhanced neovascularization. Angiogenesis is an indispensable prerequisite for the progression and metastasis of solid malignancies, which is modulated by tumor suppressors and oncogenes. We have addressed the possibility that N-myc oncogene might regulate angiogenesis in neuroblastoma. Here, we report that experimental N-Myc overexpression results in down-regulation of leukemia inhibitory factor (LIF), a modulator of endothelial cell proliferation....10 trang
106 lượt xem
4 lượt tải
Báo cáo Y học: Role of histidine 42 in ascorbate peroxidase Kinetic analysis of the H42A and H42E variants
To examine the role of the distal His42 residue in the catalytic mechanism of pea cytosolic ascorbate peroxidase, two site-directed variants were prepared in which His42 was replaced with alanine (H42A) or glutamic acid (H42E). Electronic spectra of the ferric derivatives of H42A and H42E (pH 7.0, l ¼ 0.10 M, 25.0 °C) revealed wavelength maxima [kmax (nm): 397, 509, % 540sh, 644 (H42A); 404, 516, % 538sh, 639 (H42E)] consistent with a predominantly fiveco-ordinate high-spin iron. The specific activity of H42E for oxidation of L-ascorbate (8.2 ± 0.3 UÆmg)1) was % 30-fold lower than that of the recombinant wild-type...11 trang
126 lượt xem
4 lượt tải
Báo cáo Y học: Transglutaminase-mediated polyamination of vasoactive intestinal peptide (VIP) Gln16 residue modulates VIP/PACAP receptor activity
Previous data showing an increase of receptor binding activity of [R16]VIP, a vasoactive intestinal peptide (VIP) structural analogue containing arginine at the position 16 of its amino acid sequence, have pointed out the importance of a positive charge at this site. Here, the functional characterization of three VIP polyaminated adducts (VIPDap, VIPSpd, and VIPSpm), obtained by a transglutaminasecatalysed reaction between the VIP Gln16 residue and 1,3-diaminopropane (Dap), spermidine (Spd), or spermine (Spm), is reported. ...9 trang
124 lượt xem
4 lượt tải
Báo cáo Y học: Production and chemiluminescent free radical reactions of glyoxal in lipid peroxidation of linoleic acid by the ligninolytic enzyme, manganese peroxidase
Glyoxal is a key compound involved in glyoxal oxidase (GLOX)-dependent production of glyoxylate, oxalate and H2O2 by lignin-degrading basidiomycetes. In this paper, we report that glyoxal was produced from a metabolite of ligninolytic fungi, linoleic acid, by manganese peroxidase (MnP)-dependent lipid peroxidation. In the absence of the parent substrate of linoleic acid, the dialdehyde was oxidized by MnP and Mn(III) chelate to start free radical reactions with emission of chemiluminescence at 700– 710 nm. ...9 trang
180 lượt xem
7 lượt tải
Báo cáo Y học: Chemical structure and immunoreactivity of the lipopolysaccharide of the deep rough mutant I-69 Rd–/b+ of Haemophilus influenzae
From the lipopolysaccharide of the deep rough mutant I-69 Rd–/b+ of Haemophilus influenzae two oligosaccharides were obtained after de-O-acylation and separation by high-performance anion exchange chromatography. Their chemical structures were determined by one- and two-dimensional 1H-, 13C- and 31P-NMR spectroscopy as aKdo-4P-(2 fi 6)-bGlcN-4P-(1 fi 6)-aGlcN-1P and aKdo-5P-(2 fi 6)-bGlcN-4P-(1 fi 6)-aGlcN-1P.6 trang
89 lượt xem
4 lượt tải
Báo cáo Y học: Elucidation of the role of fructose 2,6-bisphosphate in the regulation of glucose fluxes in mice usingin vivo 13 C NMR measurements of hepatic carbohydrate metabolism
Fructose 2,6-bisphosphate (Fru-2,6-P2 ) plays an important role in the regulation of major carbohydrate fluxes as both allosteric activator and inhibitor of target enzymes. To examine the role of Fru-2,6-P2in the regulation of hepatic carbohydrate metabolism in vivo,Fru-2,6-P2 levels were elevated in ADM mice with adenovirus-mediated overex-pression of a double mutant bifunctional enzyme, 6-phos-phofructo-2-kinase/fructose-2,6-bisphosphatase (n¼6), in comparison to normal control mice (control,n¼6). ...9 trang
130 lượt xem
5 lượt tải
Báo cáo Y học: Endogenous cardiac glycosides, a new class of steroid hormones
The search for endogenousdigitalishas led to the isolationof ouabain as well as several additional cardiotonic steroids of the cardenolide and bufadienolide type from blood, adre-nals, and hypothalamus.The concentration of endogenous ouabain is elevated in blood upon increased Na + uptake, hypoxia, and physical exercise.Changes in blood levels of ouabain upon physical exercise occur rapidly.9 trang
101 lượt xem
3 lượt tải
Báo cáo Y học: Characterization of a partially folded intermediate of stem bromelain at low pH
Equilibrium studies on the acid included denaturation of stem bromelain (EC 3.4.22.32) were performed by CD spectroscopy, ¯uorescence emission spectroscopy and binding of the hydrophobic dye, 1-anilino 8-naphthalene sulfonic acid (ANS). At pH 2.0, stembromelain lacks awell de®ned tertiary structure as seen by ¯uorescence and near-UVCDspectra.Far-UVCDspectra showretentionof some native like secondary structure at pH 2.0. Interdisciplinary Biotechnology Unit, Aligarh Muslim University, India Equilibrium studies on the acid included denaturation of stem bromelain (EC 3.4.22.32) were performed by CD spectroscopy, ¯uorescence emission spectroscopy and binding of the hydrophobic dye, 1-anilino 8-naphthalene sulfonic acid (ANS). At pH 2.0, stem bromelain lacks a well de®ned tertiary structure as seen by...6 trang
76 lượt xem
3 lượt tải
Báo cáo khoa học: The oxidative effect of bacterial lipopolysaccharide on native and cross-linked human hemoglobin as a function of the structure of the lipopolysaccharide A comparison of the effects of smooth and rough lipopolysaccharide
The binding of lipopolysaccharide (LPS, also known as bacterial endotoxin) to human hemoglobin is known to result in oxidation of hemoglobin to methemoglobin and hemichrome. We have investigated the effects of the LPSs from smooth and rough Escherichia coliandSalmonella minnesotaon the rate of oxidation of native oxyhemoglobin A0and hemoglobin cross-linked between thea-99 lysines.6 trang
103 lượt xem
3 lượt tải
Báo cáo khoa học: The fate of newly synthesized V-ATPase accessory subunit Ac45 in the secretory pathway
The vacuolar H + -ATPase (V-ATPase) is a multimeric enzyme complex that acidi®es organelles of the vacuolar system in eukaryotic cells. Proteins that interact with the V-ATPase may play an important role in controlling the intracellular localization and activity of the proton pump. The neuroendocrine-enriched V-ATPase accessory subunit Ac45 may represent such a protein as it has been shown to interactwith themembrane sector of theV-ATPase inonlya subset of organelles.10 trang
83 lượt xem
3 lượt tải
Báo cáo khoa học: Substrate recognition by three family 13 yeast a-glucosidases Evaluation of deoxygenated and conformationally biased isomaltosides
Important hydrogenbonding interactions between substrate OH-groups inyeasta-glucosidases andoligo-1,6-glucosidase from glycoside hydrolase family 13 have been identi®ed by measuring the rates of hydrolysis of methyla-isomaltoside and its seven monodeoxygenated analogs. The transition-state stabilization energy, DDGà, contributed by the indi-vidual OH-groups was calculated from the activities for the parent and the deoxy analogs, respectively, according toDDGà ±RTln[(Vmax/Km)analog /(Vmax/Km) parent]....7 trang
100 lượt xem
2 lượt tải
Báo cáo Y học: Determinants of antagonist binding at the a-amino-3-hydroxy5-methyl-4-isoxazolepropionic acid receptor subunit, GluR-D Role of the conserved arginine 507 and glutamate 727 residues
Previous structural andmutagenesis studies indicate that the invariant a-amino and a-carboxyl groups of glutamate receptor agonists are engaged in polar interactions with oppositely charged, conserved arginine and glutamate resi-dues in the ligand-binding domain ofa-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor.To examine the role of these residues (R507 and E727 in the GluR-D subunit) in the discrimination between agonists and anta-gonists, we analyzed the ligand-binding properties of homomeric GluR-D and its soluble ligand-binding domain withmutations at thesepositions....10 trang
97 lượt xem
3 lượt tải
Báo cáo Y học: Structural and compositional changes in very low density lipoprotein triacylglycerols during basal lipolysis
Triacylglycerols secreted by liver and carried by very low density lipoprotein (VLDL) are hydrolysed in circulation by lipoprotein and hepatic lipases. These enzymes have been shown to have positional and fatty acid specificityin vitro.If there were specificity in basal lipolysisin vivo, triacylglycerol compositionsofcirculatingandnewlysecretedVLDLwould be different. To study this we compared the composition of normal fasting VLDL triacylglycerol of Wistar rats to that obtained after blocking lipolysis by Triton WR1339, which increasedplasmaVLDL triacylglycerol concentrationabout 4.7-fold in 2 h. ...10 trang
78 lượt xem
3 lượt tải
Báo cáo Y học: Biophysical characterization of the interaction of high-density lipoprotein (HDL) with endotoxins
The interaction of bacterial endotoxins [lipopolysaccharide (LPS) and theendotoxic principle lipid A], with high-den-sity lipoprotein (HDL) from serum was investigated with a variety of physical techniques and biological assays. HDL exhibited an increase in the gel to liquid crystalline phase transition temperature Tc and a rigidification of the acyl chains of the endotoxins as measured by Fourier-transform infrared spectroscopy and differential scanningcalorimetry.10 trang
104 lượt xem
3 lượt tải
Báo cáo Y học: Probing the role of glutamic acid 139 of Anabaena ferredoxin-NADP+ reductase in the interaction with substrates
The role of the negative charge of the E139 side-chain of AnabaenaFerredoxin-NADP + reductase (FNR) in steering appropriate docking with its substrates ferredoxin, flavo-doxin and NADP + /H, that leads to efficient electron transfer (ET) is analysed by characterization of several E139 FNRmutants. Replacement of E139 affects the interaction with the different FNRsubstrates in very different ways.10 trang
85 lượt xem
2 lượt tải
Báo cáo khoa học: Kinetic studies on endo-b-galactosidase by a novel colorimetric assay and synthesis of N -acetyllactosamine-repeating oligosaccharide b-glycosides using its transglycosylation activity
Novel chromogenic substrates for endo-b-galactosidase were designed on the basis of the structural features of keratan sulfate. Galb1-4GlcNAcb1-3Galb1-4GlcNAcb-pNP (2),which consists of two repeating units ofN-acetyl-lactosamine,was synthesized enzymatically by consecutive additions of GlcNAc and Gal residues top-nitrophenyl b-N-acetyllactosaminide. In a similar manner,Glc-NAcb1-3Galb1-4GlcNAcb-pNP (1),GlcNAcb1-3Galb1-4Glcb-pNP (3),Galb1-4GlcNAcb1-3Galb1-4Glcb-pNP (4), Galb1-3GlcNAcb1-3Galb1-4Glcb-pNP (5),and Galb1-6GlcNAcb1-3Galb1-4Glcb-pNP (6) were synthesized as analogues of2. Endo-b-galactosidases released GlcNAcb-pNP or Glcb-pNP in an endo-manner from each substrate....11 trang
93 lượt xem
2 lượt tải
Chịu trách nhiệm nội dung: Nguyễn Công Hà
Doanh nghiệp quản lý: Công ty TNHH Tài Liệu trực tuyến Vi Na - GCN ĐKDN: 0307893603
Địa chỉ: 54A Nơ Trang Long, P. Bình Thạnh, TP.HCM - Điện thoại: 0283 5102 888 - Email: info@tailieu.vn
Giấy phép Mạng Xã Hội số: 670/GP-BTTTT cấp ngày 30/11/2015