749 research outputs found
Evaluation of thermal conductivity of the constituent layers in TRISO particles using Raman spectroscopy
Profile of Antibacterial Activities of Essential Oil and Oleoresin from Clove Buds against Several Food-Related Bacteria
The oil from clove buds had a wide range of pharmacological action and bioactivities and is widely used in the medicine, food and flavouring industries. In this work, the antibacterial activity of the essential oil (EO) and oleoresin (OL) from clove buds against several food-related bacteria were evaluated based on Oxford cup method, the minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) assays, and the results showed that there is no obvious difference in antibacterial activity between essential oil and oleoresin, and they exhibited better antibacterial activity against test bacteria, and the antibacterial effects depended on its concentrations and action time. Kill-time assay also showed the essential oil and oleoresin from clove buds had a significant inhibitory effect on the growth rate of surviving Staphylococcus aureus and Escherichia coli
Association between genetic polymorphisms of CYP2A13, CYP2A6 and risk of nasopharyngeal carcinoma in southern Chinese population
Abstract: Background: Cytochrome P450 2A13 (CYP2A13) and 2A6 (CYP2A6) are enzymes expressed in the human respiratory tract, exhibit high efficiency in the metabolic activation of tobacco carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). A C→T transition in the CYP2A13 gene causes Arg257Cys amino acid substitution and a deletion of the CYP2A6 gene named as CYP2A6 *4, both of them result in a significantly reduced activity toward NNK and other substrates. In this case-control study, we investigated the association between the CYP2A13 and CYP2A6 variants, smoking status and the risk of developing nasopharyngeal carcinoma (NPC) in the Cantonese population living in southern China. Materials and Methods: Genotypes of CYP2A13 and CYP2A6 genes were analyzed by using polymerase chain reaction-based restriction fragment length polymorphism (PCR-RFLP) assays and two-step PCR method. Results: Neither the CYP2A13 -3375T variants nor CYP2A6 *4 variants were associated with risk of NPC (OR = 0.84, 95% CI = 0.59-1.20, and OR = 0.83, 95% CI = 0.58-1.18, respectively) compared with their wild genotypes. Combination analysis showed that individuals with both CYP2A13 CT or TT variants and CYP2A6 *4 variants had no association with risk for NPC (OR = 0.71, 95% CI = 0.33-1.52) compared with those with both CYP2A13 CC and CYP2A6 *1/*1 genotypes. No association with the risk of NPC was observed in smokers with CYP2A13 C/T polymorphisms or smokers with CYP2A6 *4 variant polymorphisms (OR = 0.75, 95% CI = 0.43-1.32, and OR = 0.90, 95% CI = 0.27-1.70; respectively), including after stratification of smoking status. Furthermore, we did not observe association between the combination of two gene polymorphisms and smokers and risk of developing NPC, including the stratification of smoking. Discussions: Based on the results of this study, the effect of these two CYP2A13 and CYP2A6 enzymes may be not so important in developing of NPC as in other cancers, such as lung cancer. ). http://www.cancer-biology.org
3D-CT implanted interstitial brachytherapy for T2b nasopharyngeal carcinoma
<p>Abstract</p> <p>Background</p> <p>To compare the results of external beam radiotherapy in combination with 3D- computed tomography (CT)-implanted interstitial high dose rate brachytherapy (ERT/3D-HDR-BT) versus conventional external beam radiotherapy (ERT) for the treatment of stage T2b nasopharyngeal carcinoma (NPC).</p> <p>Methods</p> <p>Forty NPC patients diagnosed with stage T2b NPC were treated with ERT/3D-HDR-BT under local anesthesia. These patients received a mean dose of 60 Gy, followed by 12-20 Gy administered by 3D-HDR-BT. Another 101 patients diagnosed with non-metastatic T2b NPC received a mean dose of 68 Gy by ERT alone during the same period.</p> <p>Results</p> <p>Patients treated with ERT/3D-HDR-BT versus ERT alone exhibited an improvement in their 5-y local failure-free survival rate (97.5% vs. 80.2%, <it>P </it>= 0.012) and disease-free survival rate (92.5% vs. 73.3%, <it>P </it>= 0.014). Using multivariate analysis, administration of 3D-HDR-BT was found to be favorable for local control (<it>P </it>= 0.046) and was statistically significant for disease-free survival (<it>P </it>= 0.021). The incidence rate of acute and chronic complications between the two groups was also compared.</p> <p>Conclusions</p> <p>It is possible that the treatment modality enhances local control due to improved conformal dose distributions and the escalated radiation dose applied.</p
Data Processing Pipeline for Pointing Observations of Lunar-based Ultraviolet Telescope
We describe the data processing pipeline developed to reduce the pointing
observation data of Lunar-based Ultraviolet Telescope (LUT), which belongs to
the Chang'e-3 mission of the Chinese Lunar Exploration Program. The pointing
observation program of LUT is dedicated to monitor variable objects in a
near-ultraviolet (245-345 nm) band. LUT works in lunar daytime for sufficient
power supply, so some special data processing strategies have been developed
for the pipeline. The procedures of the pipeline include stray light removing,
astrometry, flat fielding employing superflat technique, source extraction and
cosmic rays rejection, aperture and PSF photometry, aperture correction, and
catalogues archiving, etc. It has been intensively tested and works smoothly
with observation data. The photometric accuracy is typically ~0.02 mag for LUT
10 mag stars (30 s exposure), with errors come from background noises,
residuals of stray light removing, and flat fielding related errors. The
accuracy degrades to be ~0.2 mag for stars of 13.5 mag which is the 5{\sigma}
detection limit of LUT.Comment: 10 pages, 7 figures, 4 tables. Minor changes and some expounding
words added. Version accepted for publication in Astrophysics and Space
Science (Ap&SS
Effect of p21Waf1 and p27Kip1 on centrosome replication and proliferation of breast cancer cell
Aberrant centrosome numbers are detected in virtually all cancers,increasing the risk for cell division errors and chromosomal instability. Deregulation of the centrosome duplication cycle is considered as the major contributing factor for abnormal amplification of centrosomes. p21Waf1 and p27Kip1, general CDK inhibitors by inhibiting cyclin-dependent kinase 2 (CDK2)/cyclin E and cyclin A complexes, controlled the initiation and progress of centrosome duplication . We transfected p21 Waf1, p27 Kip1 or p21 Waf1- p27 Kip1 genes into MCF-7 cells by lipofection to explore the effect of the genes on centrosome duplication and proliferation of breast cancer cell. The result shows that the cell growth was obviously inhibited after being transfected, resulting in an accumulation of cells in G1 and the proportion of cells which contained abnormal centrosomes was obviously decreased. Comparing with p21 Waf1or p27 Kip1, the effects of p21Waf1- p27 Kip1 genes are more significative. These results suggest that p21Waf1 and p27Kip1 genes could inhibit the growth of human breast cancer cells and reverse abnormal duplication of centrosomes. p21Waf1 and p27Kip1 cooperate to regulate centrosome duplication and cell cycle progress, indicating p21 Waf1- p27 Kip1 combined gene might be potential therapeutic agents of breast cancer which reveals suppressed p21Waf1 and p27Kip1 expression
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