159 research outputs found

    The Transformation Of Trust In China’s Alternative Food Networks: Disruption, Reconstruction, And Development

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    Food safety issues in China have received much scholarly attention, yet few studies systematically examined this matter through the lens of trust. More importantly, little is known about the transformation of different types of trust in the dynamic process of food production, provision, and consumption. We consider trust as an evolving interdependent relationship between different actors. We used the Beijing County Fair, a prominent ecological farmers’ market in China, as an example to examine the transformation of trust in China’s alternative food networks. We argue that although there has been a disruption of institutional trust among the general public since 2008 when the melamine-tainted milk scandal broke out, reconstruction of individual trust and development of organizational trust have been observed, along with the emergence and increasing popularity of alternative food networks. Based on more than six months of fieldwork on the emerging ecological agriculture sector in 13 provinces across China as well as monitoring of online discussions and posts, we analyze how various social factors—including but not limited to direct and indirect reciprocity, information, endogenous institutions, and altruism—have simultaneously contributed to the transformation of trust in China’s alternative food networks. The findings not only complement current social theories of trust, but also highlight an important yet understudied phenomenon whereby informal social mechanisms have been partially substituting for formal institutions and gradually have been building trust against the backdrop of the food safety crisis in China.published_or_final_versio

    Variability of wavefront aberration measurements in small pupil sizes using a clinical Shack-Hartmann aberrometer

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    BACKGROUND: Recently, instruments for the measurement of wavefront aberration in the living human eye have been widely available for clinical applications. Despite the extensive background experience on wavefront sensing for research purposes, the information derived from such instrumentation in a clinical setting should not be considered a priori precise. We report on the variability of such an instrument at two different pupil sizes. METHODS: A clinical aberrometer (COAS Wavefront Scienses, Ltd) based on the Shack-Hartmann principle was employed in this study. Fifty consecutive measurements were perfomed on each right eye of four subjects. We compared the variance of individual Zernike expansion coefficients as determined by the aberrometer with the variance of coefficients calculated using a mathematical method for scaling the expansion coefficients to reconstruct wavefront aberration for a reduced-size pupil. RESULTS: Wavefront aberration exhibits a marked variance of the order of 0.45 microns near the edge of the pupil whereas the central part appears to be measured more consistently. Dispersion of Zernike expansion coefficients was lower when calculated by the scaling method for a pupil diameter of 3 mm as compared to the one introduced when only the central 3 mm of the Shack – Hartmann image was evaluated. Signal-to-noise ratio was lower for higher order aberrations than for low order coefficients corresponding to the sphero-cylindrical error. For each subject a number of Zernike expansion coefficients was below noise level and should not be considered trustworthy. CONCLUSION: Wavefront aberration data used in clinical care should not be extracted from a single measurement, which represents only a static snapshot of a dynamically changing aberration pattern. This observation must be taken into account in order to prevent ambiguous conclusions in clinical practice and especially in refractive surgery

    Improvement of renal oxidative stress markers after ozone administration in diabetic nephropathy in rats

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    <p>Abstract</p> <p>Background</p> <p>Several complications of diabetes mellitus (DM) e.g. nephropathy (DN) have been linked to oxidative stress. Ozone, by means of oxidative preconditioning, may exert its protective effects on DN.</p> <p>Aim</p> <p>The aim of the present work is to study the possible role of ozone therapy in ameliorating oxidative stress and inducing renal antioxidant defence in streptozotocin (STZ)-induced diabetic rats.</p> <p>Methods</p> <p>Six groups (n = 10) of male Sprague Dawley rats were used as follows: Group C: Control group. Group O: Ozone group, in which animals received ozone intraperitoneally (i.p.) (1.1 mg/kg). Group D: Diabetic group, in which DM was induced by single i.p. injections of streptozotocin (STZ). Group DI: Similar to group D but animals also received subcutaneous (SC) insulin (0.75 IU/100 gm BW.). Group DO: In which diabetic rats received the same dose of ozone, 48 h after induction of diabetes. Group DIO, in which diabetic rats received the same doses of insulin and ozone, respectively. All animals received daily treatment for six weeks. At the end of the study period (6 weeks), blood pressure, blood glycosylated hemoglobin (HbA<sub>1c</sub>), serum creatinine, blood urea nitrogen (BUN), kidney tissue levels of superoxide dismutase (SOD), catalase (CAT), glutathione peroxide (GPx), aldose reductase (AR) activities and malondialdehyde (MDA) concentration were measured.</p> <p>Results</p> <p>Induction of DM in rats significantly elevated blood pressure, HbA<sub>1c</sub>, BUN, creatinine and renal tissue levels of MDA and AR while significantly reducing SOD, CAT and GPx activities. Either Insulin or ozone therapy significantly reversed the effects of DM on all parameters; in combination (DIO group), they caused significant improvements in all parameters in comparison to each alone.</p> <p>Conclusions</p> <p>Ozone administration in conjunction with insulin in DM rats reduces oxidative stress markers and improves renal antioxidant enzyme activity which highlights its potential uses in the regimen for treatment of diabetic patients.</p

    A Defined, Feeder-Free, Serum-Free System to Generate In Vitro Hematopoietic Progenitors and Differentiated Blood Cells from hESCs and hiPSCs

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    Human ESC and iPSC are an attractive source of cells of high quantity and purity to be used to elucidate early human development processes, for drug discovery, and in clinical cell therapy applications. To efficiently differentiate pluripotent cells into a pure population of hematopoietic progenitors we have developed a new 2-dimentional, defined and highly efficient protocol that avoids the use of feeder cells, serum or embryoid body formation. Here we showed that a single matrix protein in combination with growth factors and a hypoxic environment is sufficient to generate from pluripotent cells hematopoietic progenitors capable of differentiating further in mature cell types of different lineages of the blood system. We tested the differentiation method using hESCs and 9 iPSC lines generated from different tissues. These data indicate the robustness of the protocol providing a valuable tool for the generation of clinical-grade hematopoietic cells from pluripotent cells

    Expression of Mir-21 and Mir-143 in Cervical Specimens Ranging from Histologically Normal through to Invasive Cervical Cancer

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    MicroRNA expression is severely disrupted in carcinogenesis, however limited evidence is available validating results from cell-line models in human clinical cancer specimens. MicroRNA-21 (mir-21) and microRNA-143 (mir-143) have previously been identified as significantly deregulated in a range of cancers including cervical cancer. Our goal was to investigate the expression patterns of several well-studied microRNA species in cervical samples and compare the results to cell line samples.We measured the expression of mir-21 and mir-143 in 142 formalin-fixed, paraffin embedded (FFPE) cervical biopsy tissue blocks, collected from Dantec Oncology Clinic, Dakar, Senegal. MicroRNA expression analysis was performed using Taqman-based real-time PCR assays. Protein immunohistochemical staining was also performed to investigate target protein expression on 72 samples. We found that mir-21 expression increased with worsening clinical diagnosis but that mir-143 was not correlated with histology. These observations were in stark contrast to previous reports involving cervical cancer cell lines in which mir-143 was consistently down-regulated but mir-21 largely unaffected. We also identified, for the first time, that cytoplasmic expression of Programmed Cell Death Protein 4 PDCD4; a known target of mir-21) was significantly lower in women with invasive cervical carcinoma (ICC) in comparison to those with cervical intraepithelial neoplasia (2-3) or carcinoma in situ (CIN2-3/CIS), although there was no significant correlation between mir-21 and PDCD4 expression, despite previous studies identifying PDCD4 transcript as a known mir-21 target.Whilst microRNA biomarkers have a number of promising features, more studies on expression levels in histologically defined clinical specimens are required to investigate clinical relevance of discovery-based studies. Mir-21 may be of some utility in predictive screening, given that we observed a significant correlation between mir-21 expression level and worsening histological diagnosis of cervical cancer

    Protein quality control: the who’s who, the where’s and therapeutic escapes

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    In cells the quality of newly synthesized proteins is monitored in regard to proper folding and correct assembly in the early secretory pathway, the cytosol and the nucleoplasm. Proteins recognized as non-native in the ER will be removed and degraded by a process termed ERAD. ERAD of aberrant proteins is accompanied by various changes of cellular organelles and results in protein folding diseases. This review focuses on how the immunocytochemical labeling and electron microscopic analyses have helped to disclose the in situ subcellular distribution pattern of some of the key machinery proteins of the cellular protein quality control, the organelle changes due to the presence of misfolded proteins, and the efficiency of synthetic chaperones to rescue disease-causing trafficking defects of aberrant proteins

    Multifunctional Gold Nanocarriers for Cancer Theranostics - From Bench to Bedside and Back Again?

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    Scaling up genetic circuit design for cellular computing:advances and prospects

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