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排序方式: 共有1473条查询结果,搜索用时 11 毫秒
1.
Marzieh Taghipour Shamsollah Ayoubi Hossein Khademi 《Soil & Sediment Contamination》2011,20(8):921-937
Heavy metals’ origin, accumulation, and distribution in soil have been the focus of much attention by many researchers. The objective of this study was to recognize the sources of heavy metals in surface soils in Hamadan Province in western Iran using multivariate geostatistical techniques. A total of 263 surface (0–10 cm) soil samples and 18 rock samples from major parent materials were collected. Cobalt (Co), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), and zinc (Zn) contents of the samples were determined. Selected soil physical and chemical characteristics were also measured. A multivariate geostatistical analysis was performed to identify the common source of heavy metals. The quantities of Co, Cr, and Ni were found to be associated with parent rocks, corresponding to the first factor termed the “lithologic component.” The second factor was mainly attributed to Cu, which also comprised the first and third factors, indicating a mixed source both from lithologic and anthropogenic inputs. Zn and Pb contents were related to the anthropogenic activities and comprised the third factor. A significant correlation was found between metals from the lithogenic sources and selected soil properties such as soil organic matter, clay, CEC, and carbonate, indicating an interaction among them. Generally, Zn and Pb showed a less significant correlation with soil properties. 相似文献
2.
The electro-oxidation of epinephrine (EP), uric acid (UA), folic acid (FA), and their mixture has been studied by modified carbon nanotube paste electrode of 2,2'-[1,2-ethanediylbis(nitriloethylidyne)]-bis-hydroquinone using cyclic voltammetry, chronoamperometry and differential pulse voltammetry. This modified electrode exhibited potent and persistent electron mediating behavior followed by well-separated oxidation peaks towards EP, UA and FA with activation overpotential. For the ternary mixture containing EP, UA and FA the three compounds can be well separated from each other at the scan rate of 20mVs(-1). The obtained catalytic peak current, was linearly dependent on the EP, UA and FA concentrations in the range of 0.7-1200muM, 25-750muM and 15-800muM and the detection limits for EP, UA and FA were 0.216+/-0.004, 8.8+/-0.2 and 11.0+/-0.3muM, respectively. The diffusion coefficient (D), and the kinetic parameters such as electron transfer coefficient, (alpha) and heterogeneous rate constant, (k') for EP were also determined using electrochemical approaches. The modified electrode showed good sensitivity, selectivity and stability, and was employed for the determination of EP, UA and FA in the real samples. 相似文献
3.
Hakimelahi GH Shia KS Pasdar M Hakimelahi S Khalafi-Nezhad A Soltani MN Mei NW Mei HC Saboury AA Rezaei-Tavirani M Moosavi-Movahedi AA 《Bioorganic & medicinal chemistry》2002,10(9):2927-2932
A novel cephalosporin derivative of monohydroguaiaretic acid (cephem-M(3)N, 7) was synthesized and found to possess anticancer activity against human leukemia (K562), breast carcinoma (MCF7), human lung cancer (A549), human colon cancer (Colo205) and pancreatic cancer cells (Capan2 and MiaPaCa2). A tumor targeting fusion protein (dsFv3-beta-lactamase) was also used in conjunction with cephem-based M(3)N 7 and its potency toward K562, MCF7, A549, Colo205, Capan2, and MiaPaCa2 was found to approach that of the free M(3)N (4). In the presence of dsFv3-beta-lactamase, tumor cells were found to be much more susceptible to conjugate 7 than normal human embryonic lung (HEL) cells and normal fibroblasts (Hef522). These notions provide a new approach to the use of nordihydroguaiaretic acid (NDGA) and its derivatives for antitumor therapy. 相似文献
4.
Ken-ichi Uchida Takamasa Hirai Fuyuki Ando Hossein Sepehri-Amin 《Liver Transplantation》2024,14(3):2302375
In artificially tilted multilayers comprising two different conductors that are alternately and obliquely stacked, transverse thermoelectric conversion occurs, in which charge and heat currents are interconverted in the orthogonal direction. Although transverse thermoelectric conversion also occurs in homogeneous materials as an intrinsic transport phenomenon owing to the effects of magnetic fields, magnetization, and spins on conduction carriers, such magneto-thermoelectric effects are investigated independently of thermoelectrics for artificially tilted multilayers. Here, this study shows that the synergy of these different principles improves the performance of transverse thermoelectric conversion. Using lock-in thermography techniques, transverse thermoelectric conversion processes are visualized in artificially tilted multilayers and the experiments clarify how nonuniform charge currents are converted into orthogonal heat currents. Through the measurements of temperature change under magnetic fields, the contributions of the magneto-thermoelectric effects are quantified in the artificially tilted multilayers and magnetically enhanced hybrid transverse thermoelectric cooling is demonstrated. By replacing one of the conductors in the multilayer with permanent magnets, the same functionality is obtained even in the absence of magnetic fields, paving the way for the creation of “thermoelectric permanent magnets” that exhibit efficient transverse thermoelectric conversion together with spontaneous magnetization. This study provides a new material design guideline for transverse thermoelectrics. 相似文献
5.
Abdel-Mottaleb Y Clynen E Jalali A Bosmans F Vatanpour H Schoofs L Tytgat J 《FEBS letters》2006,580(26):6254-6258
The very first member of K(+) channels toxins from the venom of the Iranian scorpion Odonthobuthus doriae (OdK1) was purified, sequenced and characterized physiologically. OdK1 has 29 amino acids, six conserved cysteines and a pI value of 4.95. Based on multiple sequence alignments, OdK1 was classified as alpha-KTx 8.5. The pharmacological effects of OdK1 were studied on six different cloned K(+) channels (vertebrate Kv1.1-Kv1.5 and Shaker IR) expressed in Xenopus laevis oocytes. Interestingly, OdK1 selectively inhibited the currents through Kv1.2 channels with an IC50 value of 183+/-3 nM but did not affect any of the other channels. 相似文献
6.
Davoud Nouri Inanlou Bagher Yakhchali Hossein Khanahmad Mossa Gardaneh Hesam Movassagh Reza Ahangari Cohan Mehdi Shafiee Ardestani Reza Mahdian Sirous Zeinali 《Biotechnology letters》2010,32(11):1615-1621
We have developed an integrase-defective lentiviral (LV) vector in combination with a gene-targeting approach for gene therapy
of β-thalassemia. The β-globin gene-targeting construct has two homologous stems including sequence upstream and downstream
of the β-globin gene, a β-globin gene positioned between hygromycin and neomycin resistant genes and a herpes simplex virus
type 1 thymidine kinase (HSVtk) suicide gene. Utilization of integrase-defective LV as a vector for the β-globin gene increased the number of selected clones
relative to non-viral methods. This method represents an important step toward the ultimate goal of a clinical gene therapy
for β-thalassemia. 相似文献
7.
Soni Pullamsetti Stefanie Krick Hüseyin Yilmaz Hossein Ardeschir Ghofrani Christian Schudt Norbert Weissmann Beate Fuchs Werner Seeger Friedrich Grimminger Ralph Theo Schermuly 《Respiratory research》2005,6(1):128
Background
The aim of the study was to assess the chronic effects of combined phosphodiesterase 3/4 inhibitor tolafentrine, administered by inhalation, during monocrotaline-induced pulmonary arterial hypertension (PAH) in rats.Methods
CD rats were given a single subcutaneous injection of monocrotaline to induce PAH. Four weeks after, rats were subjected to inhalation of tolafentrine or sham nebulization in an unrestrained, whole body aerosol exposure system. In these animals (i) the acute pulmonary vasodilatory efficacy of inhaled tolafentrine (ii) the anti-remodeling effect of long-term inhalation of tolafentrine (iii) the effects of tolafentrine on the expression profile of 96 genes encoding cell adhesion and extracellular matrix regulation were examined. In addition, the inhibitory effect of tolafentrine on ex vivo isolated pulmonary artery SMC cell migration was also investigated.Results
Monocrotaline injection provoked severe PAH (right ventricular systolic pressure increased from 25.9 ± 4.0 to 68.9 ± 3.2 after 4 weeks and 74.9 ± 5.1 mmHg after 6 weeks), cardiac output depression and right heart hypertrophy. The media thickness of the pulmonary arteries and the proportion of muscularization of small precapillary resistance vessels increased dramatically, and the migratory response of ex-vivo isolated pulmonary artery smooth muscle cells (PASMC) was increased. Micro-arrays and subsequent confirmation with real time PCR demonstrated upregulation of several extracellular matrix regulation and adhesion genes, such as matrixmetalloproteases (MMP) 2, 8, 9, 10, 11, 12, 20, Icam, Itgax, Plat and serpinb2. When chronically nebulized from day 28 to 42 (12 daily aerosol maneuvers), after full establishment of severe pulmonary hypertension, tolafentrine reversed about 60% of all hemodynamic abnormalities, right heart hypertrophy and monocrotaline-induced structural lung vascular changes, including the proportion of pulmonary artery muscularization. The upregulation of extracellular matrix regulation and adhesion genes was reduced by nearly 80% by inhalation of the tolafentrine. When assessed in vitro, tolafentrine blocked the enhanced PASMC migratory response.Conclusion
In conclusion, we demonstrate for the first time that inhalation of combined PDE3/4 inhibitor reverses pulmonary hypertension fully developed in response to monocrotaline in rats. This "reverse-remodeling" effect includes structural changes in the lung vascular wall and key molecular pathways of matrix regulation, concomitant with 60% normalization of hemodynamics. 相似文献8.
9.
Foroughi Kobra Jahanbani Sarvin Nazarnezhad Simin Khastar Hossein Jafarisani Moslem Tashakori Mersedeh Kazemi Seyedeh Sareh 《International journal of peptide research and therapeutics》2020,26(2):1115-1126
International Journal of Peptide Research and Therapeutics - Survivin is a unique member of the inhibitor of apoptosis protein family. Research has approved Survivin’s ability to interact... 相似文献
10.
Hossein Vaheed Seyed Abbas Shojaosadati Hasan Galip 《Journal of industrial microbiology & biotechnology》2011,38(1):101-111
In this research, ethanol production from carob pod extract (extract) using Zymomonas mobilis with medium optimized by Plackett–Burman (P–B) and response surface methodologies (RSM) was studied. Z. mobilis was recognized as useful for ethanol production from carob pod extract. The effects of initial concentrations of sugar, peptone,
and yeast extract as well as agitation rate (rpm), pH, and culture time in nonhydrolyzed carob pod extract were investigated.
Significantly affecting variables (P = 0.05) in the model obtained from RSM studies were: weights of bacterial inoculum, initial sugar, peptone, and yeast extract.
Acid hydrolysis was useful to complete conversion of sugars to glucose and fructose. Nonhydrolyzed extract showed higher ethanol
yield and residual sugar compared with hydrolyzed extract. Ethanol produced (g g−1 initial sugar, as the response) was not significantly different (P = 0.05) when Z. mobilis performance was compared in hydrolyzed and nonhydrolyzed extract. The maximum ethanol of 0.34 ± 0.02 g g−1 initial sugar was obtained at 30°C, initial pH 5.2, and 80 rpm, using concentrations (g per 50 mL culture media) of: inoculum
bacterial dry weight, 0.017; initial sugar, 5.78; peptone, 0.43; yeast extract, 0.43; and culture time of 36 h. 相似文献