173 research outputs found

    Strain Softening Induced by High Pressure Torsion in Copper Alloys

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    Three kinds of Cu-Al alloys and a pure Cu sample with different stacking fault energies (SFEs) are deformed using room temperature rolling (RR) and high pressure torsion (HPT), respectively. The microstructure is analysed by means of transaction electron microscopy and X-ray diffraction. It is found that HIPT is more feasible to obtain nanocrystals and profuse twins. Tailoring the SFE can promote sample strength without sacrificing the ductility of the Cu alloys. The tensile properties of samples processed by HPT and RR are compared. It is discovered that the HPT process leads to the strain softening phenomenon in samples with relatively high SFE. The excellent mechanical properties can be obtained in samples deformed by HPT with a SFE of 6 mJ/m(2), in which strain softening was restrained and strain hardening played a dominant role in the deformation process. The relationship between tensile properties and microstructures of the deformed metals is also investigated.110Ysciescopu

    Efficacy and tolerability of bevacizumab plus capecitabine as first-line therapy in patients with advanced hepatocellular carcinoma

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    Molecularly targeted agents with anti-angiogenic activity, including bevacizumab, have demonstrated clinical activity in patients with advanced /metastatic hepatocellular carcinoma (HCC). This multicentre phase II study involving patients from several Asian countries sought to evaluate the safety and efficacy of bevacizumab plus capecitabine in this population. METHODS: Histologically proven/clinically diagnosed advanced HCC patients received bevacizumab 7.5 mg kg(-1) on day 1 and capecitabine 800 mg m(-2) twice daily on days 1-14 every 3 weeks as first-line therapy. RESULTS: A total of 45 patients were enrolled; 44 (96%) had extrahepatic metastasis and/or major vessel invasion and 30( 67%) had hepatitis B. No grade 3/4 haematological toxicity occurred. Treatment-related grade 3/4 non-haematological toxicities included diarrhoea (n = 2, 4%), nausea/ vomiting ( n = 1, 2%), gastrointestinal bleeding (n = 4, 9%) and hand- foot syndrome (n = 4, 9%). The overall response rate ( RECIST) was 9% and the disease control rate was 52%. Overall , median progression-free survival (PFS) and overall survival(OS) were 2.7 and 5.9 months, respectively. Median PFS and OS were 3.6 and 8.2 months, respectively, for Cancer of the Liver Italian Programme (CLIP) score <= 3 patients, and 1.4 and 3.3 months, respectively, for CLIP score 4 patients. CONCLUSION: The bevacizumab-capecitabine combination shows good tolerability and modest anti-tumour activity in patients with advanced HCC

    Midkine is a NF-ÎșB-inducible gene that supports prostate cancer cell survival

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    BackgroundMidkine is a heparin-binding growth factor that is over-expressed in various human cancers and plays important roles in cell transformation, growth, survival, migration, and angiogenesis. However, little is known about the upstream factors and signaling mechanisms that regulate midkine gene expression.MethodsTwo prostate cancer cell lines LNCaP and PC3 were studied for their expression of midkine. Induction of midkine expression in LNCaP cells by serum, growth factors and cytokines was determined by Western blot analysis and/or real-time quantitative reverse-transcription - polymerase chain reaction (RT-PCR). The cell viability was determined by the trypan blue exclusion assay when the LNCaP cells were treated with tumor necrosis factor alpha (TNFalpha) and/or recombinant midkine. When the LNCaP cells were treated with recombinant midkine, activation of intracellular signalling pathways was determined by Western blot analysis. Prostate tissue microarray slides containing 129 cases (18 normal prostate tissues, 40 early stage cancers, and 71 late stage cancers) were assessed for midkine expression by immunohistochemical staining.ResultsWe identified that fetal bovine serum, some growth factors (epidermal growth factor, androgen, insulin-like growth factor-I, and hepatocyte growth factor) and cytokines (TNFalpha and interleukin-1beta) induced midkine expression in a human prostate cancer cell line LNCaP cells. TNFalpha also induced midkine expression in PC3 cells. TNFalpha was the strongest inducer of midkine expression via nuclear factor-kappa B pathway. Midkine partially inhibited TNFalpha-induced apoptosis in LNCaP cells. Knockdown of endogenous midkine expression by small interfering RNA enhanced TNFalpha-induced apoptosis in LNCaP cells. Midkine activated extracellular signal-regulated kinase 1/2 and p38 mitogen-activated protein kinase pathways in LNCaP cells. Furthermore, midkine expression was significantly increased in late stage prostate cancer, which coincides with previously reported high serum levels of TNFalpha in advanced prostate cancer.ConclusionThese findings provide the first demonstration that midkine expression is induced by certain growth factors and cytokines, particularly TNFalpha, which offers new insight into understanding how midkine expression is increased in the late stage prostate cancer

    Review of risk factors for human echinococcosis prevalence on the Qinghai-Tibet Plateau, China: a prospective for control options

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    Objective: Echinococcosis is a major parasitic zoonosis of public health importance in western China. In 2004, the Chinese Ministry of Health estimated that 380,000 people had the disease in the region. The Qinghai-Tibet Plateau is highly co-endemic with both alveolar echinococcosis (AE) and cystic echinococcosis (CE). In the past years, the Chinese government has been increasing the financial support to control the diseases in this region. Therefore, it is very important to identify the significant risk factors of the diseases by reviewing studies done in the region in the past decade to help policymakers design appropriate control strategies. Review: Selection criteria for which literature to review were firstly defined. Medline, CNKI (China National Knowledge Infrastructure), and Google Scholar were systematically searched for literature published between January 2000 and July 2011. Significant risk factors found by single factor and/or multiple factors analysis were listed, counted, and summarized. Literature was examined to check the comparability of the data; age and sex specific prevalence with same data structures were merged and used for further analysis. A variety of assumed social, economical, behavioral, and ecological risk factors were studied on the Plateau. Those most at risk were Tibetan herdsmen, the old and female in particular. By analyzing merged comparable data, it was found that females had a significant higher prevalence, and a positive linearity relationship existed between echinococcosis prevalence and increasing age. In terms of behavioral risk factors, playing with dogs was mostly correlated with CE and/or AE prevalence. In terms of hygiene, employing ground water as the drinking water source was significantly correlated with CE and AE prevalence. For definitive hosts, dog related factors were most frequently identified with prevalence of CE or/and AE; fox was a potential risk factor for AE prevalence only. Overgrazing and deforestation were significant for AE prevalence only. Conclusion: Tibetan herdsmen communities were at the highest risk of echinococcosis prevalence and should be the focus of echinococcosis control. Deworming both owned and stray dogs should be a major measure for controlling echinococcosis; treatment of wild definitive hosts should also be considered for AE endemic areas. Health education activities should be in concert with the local people's education backgrounds and languages in order to be able to improve behaviors. Further researches are needed to clarify the importance of wild hosts for AE/CE prevalence, the extent and range of the impacts of ecologic changes (overgrazing and deforestation) on the AE prevalence, and risk factors in Tibet

    Molecular Cloning and Characterization of Two Genes Encoding Dihydroflavonol-4-Reductase from Populus trichocarpa

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    Dihydroflavonol 4-reductase (DFR, EC 1.1.1.219) is a rate-limited enzyme in the biosynthesis of anthocyanins and condensed tannins (proanthocyanidins) that catalyzes the reduction of dihydroflavonols to leucoanthocyanins. In this study, two full-length transcripts encoding for PtrDFR1 and PtrDFR2 were isolated from Populus trichocarpa. Sequence alignment of the two PtrDFRs with other known DFRs reveals the homology of these genes. The expression profile of PtrDFRs was investigated in various tissues of P. trichocarpa. To determine their functions, two PtrDFRs were overexpressed in tobacco (Nicotiana tabacum) via Agrobacterium-mediated transformation. The associated color change in the flowers was observed in all 35S:PtrDFR1 lines, but not in 35S:PtrDFR2 lines. Compared to the wild-type control, a significantly higher accumulation of anthocyanins was detected in transgenic plants harboring the PtrDFR1. Furthermore, overexpressing PtrDFR1 in Chinese white poplar (P. tomentosa Carr.) resulted in a higher accumulation of both anthocyanins and condensed tannins, whereas constitutively expressing PtrDFR2 only improved condensed tannin accumulation, indicating the potential regulation of condensed tannins by PtrDFR2 in the biosynthetic pathway in poplars
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