321 research outputs found
Thermal conductivity of deformed carbon nanotubes
We investigate the thermal conductivity of four types of deformed carbon
nanotubes by using the nonequilibrium molecular dynamics method. It is reported
that various deformations have different influence on the thermal properties of
carbon nanotubes. For the bending carbon nanotubes, the thermal conductivity is
independent on the bending angle. However, the thermal conductivity increases
lightly with XY-distortion and decreases rapidly with Z-distortion. The thermal
conductivity does not change with the screw ratio before the breaking of carbon
nanotubes but decreases sharply after the critical screw ratio.Comment: 6figure
Effect of corilagin on cerebral ischaemia/reperfusioninduced cerebral injury in a rat model
Purpose: To evaluate the neuroprotective effects of corilagin in cerebral ischaemia-induced cerebral injury in a rat model. Methods: Cerebral ischaemia was induced by middle cerebral artery occlusion (MCAO). The animals were separated into five groups, including a control group that underwent surgery without inserting a monofilament; MCAO group that received saline; corilagin-treated group (20 mg/kg corilagin, intraperitoneally for 7 days after reperfusion); Tat-Beclin-1-treated group (intraperitoneal injection of 1.5mg/kg of Tat-Beclin-1 on the 3rd and 6th days after MCAO); and corilagin + Tat-Beclin-1-treated group (corilagin for 7 days and Tat-Beclin-1 on the 3rd and 6th days after MCAO). At the end of the treatments, neurological deficit, brain oedema, and volume of infarct were determined in all the animals. Moreover, the level of autophagy in infarcted tissues was evaluated by immunofluorescence, real-time PCR, and western blotting. Results: There was a significant decrease in neurological deficit, brain oedema, and volume of infarcted tissue in corilagin-treated group when compared with MCAO- and Tat-Beclin-1-treated groups. Treatment with corilagin attenuated the autophagy of astrocytes and neurons in cerebral infarcted tissue, as demonstrated by immunofluorescence, quantitative PCR, and western blotting data. Conclusion: Corlagin has a protective effect against neuronal damage in cerebral ischaemic rats by decreasing neurological deficit score, infarct volume, and water content of cerebral tissue. Corlagin attenuates autophagy in cerebral tissue, thus protecting cerebral ischaemic rats from neuronal damage. Keywords: Corilagin, Cerebral ischaemia, Autophagy, Tat-Beclin-1, Neronal damage, Astrocytes, Neurological deficit score, Infarct volum
Near-infrared quantum cutting in Tm3+/Yb3+-doped phosphate glasses
Abstract A series of phosphate glasses with compositions of 30SrO-60P2O5-10Na2O-0.5Tm2O3-xYb2O3(x = 0, 1, 5, 9, 11 in mol%) were manufactured by melt-casting method, the quantum cutting between the Tm3+ and Yb3+ in the phosphate glasses is investigated, the energy transfer from Tm3+:1G4 to Yb3+:2F5/2 is proved. According to calculate, the highest quantum efficiency is up to 159.9%, the emission wavelength is at 1020 nm, matching the energy band gap of a silicon solar cell well, therefor, these phosphate glasses could potentially be used in silicon solar cells
Can Determination of Circulating Endothelial Cells and Serum Caspase-Cleaved CK18 Predict for Response and Survival in Patients with Advanced Non–Small-Cell Lung Cancer Receiving Endostatin and Paclitaxel–Carboplatin Chemotherapy? A Retrospective Study
Introduction:Early prediction of the efficacy of a combination of an antiangiogenic drug with cytotoxic chemotherapy is a significant challenge. In that regard, circulating endothelial cells (CECs) and cytokeratins (CKs) seem to reflect their roles in both tumor angiogenesis and tumor cell death.Methods:Patients with advanced, previously untreated non–small-cell lung cancer were randomly assigned to an endostatin treatment group (paclitaxel + carboplatin + endostatin) and a control group (paclitaxel + carboplatin + placebo). A total of 122 patients were evaluated, of whom 107 had measurements of blood CECs, CK8, caspase-cleaved CK18 (ccCK18), and uncleaved CK18 (CK18) before and at weeks 3 and 6 of treatment, respectively.Results:Higher baseline CECs in patients with a tumor response (partial remission + stable disease, p = 0.002 for the entire group; p = 0.000 for the treatment group) were observed. The number of CECs decreased significantly after endostatin treatment (p = 0.000), whereas CK levels increased. Increased levels of ccCK18 and CK18, but not CK8, reached significance (p = 0.001 and p = 0.048, respectively) when compared with the baseline. Tumor response showed a strong correlation with reduction of CECs (p = 0.000) and increase of ccCK18 (p = 0.040) after endostatin therapy. Cutoff values of changes of CECs and ccCK18 for prediction of survival were 0.58/μl and 19.6 ng/ml, respectively. Reduction of CECs and increase of ccCK18 significantly correlated with longer median survival (p = 0.013 and p = 0.016 for progression-free survival; p = 0.009 and p = 0.012 for overall survival, respectively).Conclusions:CECs and CKs could be biomarkers for selecting patients with non–small-cell lung cancer who will benefit from treatment with endostatin in combination with paclitaxel plus carboplatin
Zinc Overload Enhances APP Cleavage and Aβ Deposition in the Alzheimer Mouse Brain
BACKGROUND: Abnormal zinc homeostasis is involved in β-amyloid (Aβ) plaque formation and, therefore, the zinc load is a contributing factor in Alzheimer's disease (AD). However, the involvement of zinc in amyloid precursor protein (APP) processing and Aβ deposition has not been well established in AD animal models in vivo. METHODOLOGY/PRINCIPAL FINDINGS: In the present study, APP and presenilin 1 (PS1) double transgenic mice were treated with a high dose of zinc (20 mg/ml ZnSO4 in drinking water). This zinc treatment increased APP expression, enhanced amyloidogenic APP cleavage and Aβ deposition, and impaired spatial learning and memory in the transgenic mice. We further examined the effects of zinc overload on APP processing in SHSY-5Y cells overexpressing human APPsw. The zinc enhancement of APP expression and cleavage was further confirmed in vitro. CONCLUSIONS/SIGNIFICANCE: The present data indicate that excess zinc exposure could be a risk factor for AD pathological processes, and alteration of zinc homeostasis is a potential strategy for the prevention and treatment of AD
Identification of the initial molecular changes in response to circulating angiogenic cells-mediated therapy in critical limb ischemia
BackgroundCritical limb ischemia (CLI) constitutes the most aggressive form of peripheral arterial occlusive disease, characterized by the blockade of arteries supplying blood to the lower extremities, significantly diminishing oxygen and nutrient supply. CLI patients usually undergo amputation of fingers, feet, or extremities, with a high risk of mortality due to associated comorbidities.Circulating angiogenic cells (CACs), also known as early endothelial progenitor cells, constitute promising candidates for cell therapy in CLI due to their assigned vascular regenerative properties. Preclinical and clinical assays with CACs have shown promising results. A better understanding of how these cells participate in vascular regeneration would significantly help to potentiate their role in revascularization.Herein, we analyzed the initial molecular mechanisms triggered by human CACs after being administered to a murine model of CLI, in order to understand how these cells promote angiogenesis within the ischemic tissues.MethodsBalb-c nude mice (n:24) were distributed in four different groups: healthy controls (C, n:4), shams (SH, n:4), and ischemic mice (after femoral ligation) that received either 50 mu l physiological serum (SC, n:8) or 5x10(5) human CACs (SE, n:8). Ischemic mice were sacrificed on days 2 and 4 (n:4/group/day), and immunohistochemistry assays and qPCR amplification of Alu-human-specific sequences were carried out for cell detection and vascular density measurements. Additionally, a label-free MS-based quantitative approach was performed to identify protein changes related.ResultsAdministration of CACs induced in the ischemic tissues an increase in the number of blood vessels as well as the diameter size compared to ischemic, non-treated mice, although the number of CACs decreased within time. The initial protein changes taking place in response to ischemia and more importantly, right after administration of CACs to CLI mice, are shown.ConclusionsOur results indicate that CACs migrate to the injured area; moreover, they trigger protein changes correlated with cell migration, cell death, angiogenesis, and arteriogenesis in the host. These changes indicate that CACs promote from the beginning an increase in the number of vessels as well as the development of an appropriate vascular network.Institute of Health Carlos III, ISCIII; Junta de Andaluci
A mass vaccination campaign targeting adults and children to prevent typhoid fever in Hechi; Expanding the use of Vi polysaccharide vaccine in Southeast China: A cluster-randomized trial
BACKGROUND: One of the goals of this study was to learn the coverage, safety and logistics of a mass vaccination campaign against typhoid fever in children and adults using locally produced typhoid Vi polysaccharide (PS) and group A meningococcal PS vaccines in southern China. METHODS: The vaccination campaign targeted 118,588 persons in Hechi, Guangxi Province, aged between 5 to 60 years, in 2003. The study area was divided into 107 geographic clusters, which were randomly allocated to receive one of the single-dose parenteral vaccines. All aspects regarding vaccination logistics, feasibility and safety were documented and systematically recorded. Results of the logistics, feasibility and safety are reported. RESULTS: The campaign lasted 5 weeks and the overall vaccination coverage was 78%. On average, the 30 vaccine teams gave immunizations on 23 days. Vaccine rates were higher in those aged ≤ 15 years (90%) than in adolescents and young adults (70%). Planned mop-up activities increased the coverage by 17%. The overall vaccine wastage was 11%. The cold chain was maintained and documented. 66 individuals reported of adverse events out of all vaccinees, where fever (21%), malaise (19%) and local redness (19%) were the major symptoms; no life-threatening event occurred. Three needle-sharp events were reported. CONCLUSION: The mass immunization proved feasible and safe, and vaccine coverage was high. Emphasis should be placed on: injection safety measures, community involvement and incorporation of mop-up strategies into any vaccination campaign. School-based and all-age Vi mass immunizations programs are potentially important public health strategies for prevention of typhoid fever in high-risk populations in southern China
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