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排序方式: 共有626条查询结果,搜索用时 15 毫秒
31.
High-performance thin-layer chromatography-bioautography for multiple antibiotic residues in cow's milk 总被引:2,自引:0,他引:2
Ramirez A Gutiérrez R Diaz G González C Pérez N Vega S Noa M 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2003,784(2):315-322
An analytical method to identify and quantify multiple antibiotic residues (chloramphenicol, ampicillin, benzylpenicillin, dicloxacillin and erythromycin) in cow's milk by high-performance thin-layer chromatography (HPTLC) combined with bioautography was developed. The test microorganism used for bioautography was Bacillus subtilis ATCC 6633. Antibiotic residues were extracted with acetonitrile, fat eliminated with petroleum ether and residues isolated with dichloromethane The sensitivity of the method guarantees the detection of the above-mentioned antibiotics at levels below maximum residue limits (MRL) allowed for milk. Percentage recoveries ranged between 90 and 100%, with coefficients of variation between 7.2 and 21.3%. Some advantages of this methodology over thin-layer chromatography (TLC)/bioautography are also discussed. 相似文献
32.
Molecular techniques offer new approaches for malaria field trials, particularly PCR techniques, which facilitate accurate diagnosis of Plasmodium infections and increase the power of estimates of vaccine effects on malaria prevalence or incidence. Molecular methods also help to assess selective effects of vaccines. Longitudinal genotyping data can be used to initiate novel analyses of parasite dynamics, including estimates of incidence of infection with individual parasite clones and duration of infections. In addition, high-throughput methods can be used to apply these techniques routinely in randomized controlled trials, as well as programme-based evaluations of malaria control. 相似文献
33.
Benjamin Kupfer Koushik Majhi David A. Keller Yaniv Bouhadana Sven Rühle Hannah Noa Barad Assaf Y. Anderson Arie Zaban 《Liver Transplantation》2015,5(1)
Co3O4 is investigated as a light absorber for all‐oxide thin‐film photovoltaic cells because of its nearly ideal optical bandgap of around 1.5 eV. Thin film TiO2/Co3O4 heterojunctions are produced by spray pyrolysis of TiO2 as a window layer, followed by pulsed laser deposition of Co3O4 as a light absorbing layer. The photovoltaic performance is investigated as a function of the Co3O4 deposition temperature and a direct correlation is found. The deposition temperature seems to affect both the crystallinity and the morphology of the absorber, which affects device performance. A maximum power of 22.7 μW cm?2 is obtained at the highest deposition temperature (600 °C) with an open circuit photovoltage of 430 mV and a short circuit photocurrent density of 0.2 mA cm?2. Performing deposition at 600 °C instead of room temperature improves power by an order of magnitude and reduces the tail states (Urbach edge energy). These phenomena can be explained by larger grains that grows at high temperature, as opposed to many nucleation events that occur at lower temperature. 相似文献
34.
Noa Safra Louisa J. Hayward Miriam Aguilar Benjamin N. Sacks Jodi L. Westropp F. Charles Mohr Cathryn S. Mellersh Danika L. Bannasch 《PloS one》2015,10(8)
The aim of this study was to investigate the frequency of regional DNA variants upstream to the translation initiation site of the canine Cyclooxygenase-2 (Cox-2) gene in healthy dogs. Cox-2 plays a role in various disease conditions such as acute and chronic inflammation, osteoarthritis and malignancy. A role for Cox-2 DNA variants in genetic predisposition to canine renal dysplasia has been proposed and dog breeders have been encouraged to select against these DNA variants. We sequenced 272–422 bases in 152 dogs unaffected by renal dysplasia and found 19 different haplotypes including 11 genetic variants which had not been described previously. We genotyped 7 gray wolves to ascertain the wildtype variant and found that the wolves we analyzed had predominantly the second most common DNA variant found in dogs. Our results demonstrate an elevated level of regional polymorphism that appears to be a feature of healthy domesticated dogs. 相似文献
35.
Amandine Scandolera Fanja Rabenoelina Carine Chaintreuil Anthony Rusciani Pascal Maurice Sébastien Blaise Béatrice Romier-Crouzet Hassan El Btaouri Laurent Martiny Laurent Debelle Laurent Duca 《PloS one》2015,10(6)
Degradation of elastin leads to the production of elastin-derived peptides (EDP), which exhibit several biological effects, such as cell proliferation or protease secretion. Binding of EDP on the elastin receptor complex (ERC) triggers lactosylceramide (LacCer) production and ERK1/2 activation following ERC Neu-1 subunit activation. The ability for ERC to transduce signals is lost during aging, but the mechanism involved is still unknown. In this study, we characterized an in vitro model of aging by subculturing human dermal fibroblasts. This model was used to understand the loss of EDP biological activities during aging. Our results show that ERC uncoupling does not rely on Neu-1 or PPCA mRNA or protein level changes. Furthermore, we observe that the membrane targeting of these subunits is not affected with aging. However, we evidence that Neu-1 activity and LacCer production are altered. Basal Neu-1 catalytic activity is strongly increased in aged cells. Consequently, EDP fail to promote Neu-1 catalytic activity and LacCer production in these cells. In conclusion, we propose, for the first time, an explanation for ERC uncoupling based on the age-related alterations of Neu-1 activity and LacCer production that may explain the loss of EDP-mediated effects occurring during aging. 相似文献
36.
Nirit Lev Yael Barhum Tali Ben-Zur Israel Aharony Lena Trifonov Noa Regev Eldad Melamed Arie Gruzman Daniel Offen 《PloS one》2015,10(5)
Drugs currently used for treating Parkinson''s disease patients provide symptomatic relief without altering the neurodegenerative process. Our aim was to examine the possibility of using DJ-1 (PARK7), as a novel therapeutic target for Parkinson''s disease. We designed a short peptide, named ND-13. This peptide consists of a 13 amino acids segment of the DJ-1-protein attached to 7 amino acids derived from TAT, a cell penetrating protein. We examined the effects of ND-13 using in vitro and in vivo experimental models of Parkinson''s disease. We demonstrated that ND-13 protects cultured cells against oxidative and neurotoxic insults, reduced reactive oxygen species accumulation, activated the protective erythroid-2 related factor 2 system and increased cell survival. ND-13 robustly attenuated dopaminergic system dysfunction and in improved the behavioral outcome in the 6-hydroxydopamine mouse model of Parkinson''s disease, both in wild type and in DJ-1 knockout mice. Moreover, ND-13 restored dopamine content in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine mouse model. These findings validate DJ-1 as a promising therapeutic target in Parkinson''s disease and identify a novel peptide with clinical potential, which may be significant for a broader range of neurological diseases, possibly with an important impact for the neurosciences. 相似文献
37.
Arthur R. Grossman Steven J. Karpowicz Mark Heinnickel David Dewez Blaise Hamel Rachel Dent Krishna K. Niyogi Xenie Johnson Jean Alric Francis-André Wollman Huiying Li Sabeeha S. Merchant 《Photosynthesis research》2010,106(1-2):3-17
Chlamydomonas reinhardtii, a unicellular green alga, has been exploited as a reference organism for identifying proteins and activities associated with the photosynthetic apparatus and the functioning of chloroplasts. Recently, the full genome sequence of Chlamydomonas was generated and a set of gene models, representing all genes on the genome, was developed. Using these gene models, and gene models developed for the genomes of other organisms, a phylogenomic, comparative analysis was performed to identify proteins encoded on the Chlamydomonas genome which were likely involved in chloroplast functions (or specifically associated with the green algal lineage); this set of proteins has been designated the GreenCut. Further analyses of those GreenCut proteins with uncharacterized functions and the generation of mutant strains aberrant for these proteins are beginning to unmask new layers of functionality/regulation that are integrated into the workings of the photosynthetic apparatus. 相似文献
38.
39.
Dynamic binding of Ku80, Ku70 and NF90 to the IL-2 promoter in vivo in activated T-cells 总被引:2,自引:0,他引:2 下载免费PDF全文
Shi L Qiu D Zhao G Corthesy B Lees-Miller S Reeves WH Kao PN 《Nucleic acids research》2007,35(7):2302-2310
40.
Lippa B Kauffman GS Arcari J Kwan T Chen J Hungerford W Bhattacharya S Zhao X Williams C Xiao J Pustilnik L Su C Moyer JD Ma L Campbell M Steyn S 《Bioorganic & medicinal chemistry letters》2007,17(11):3081-3086
The synthesis and biological evaluation of potent and selective inhibitors of the erbB2 kinase is presented. Based on the 4-anilinoquinazoline chemotype, the syntheses of several new series of erbB2 inhibitors are described with quinazoline and pyrido[4,3-d]pyrimidine cores. The vast majority of these compounds are found to be >100x selective over the closely related EGFR kinase. Two lead compounds are further shown to have low clearance and moderate bioavailability in rat. 相似文献