246 research outputs found

    Selecting Socio-scientific Issues for Teaching: A Grounded Theory Study of How Science Teachers Collaboratively Design SSI-Based Curricula

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    Currently there is little guidance given to teachers in selecting focal issues for socio-scientific issues (SSI)-based teaching and learning. As a majority of teachers regularly collaborate with other teachers, understanding what factors influence collaborative SSI-based curriculum design is critical. We invited 18 secondary science teachers to participate in a professional development on SSI-based instruction and curriculum design. Through intentional design, we studied how these teachers formed curriculum design teams and how they selected focal issues for SSI-based curriculum units. We developed substantiative grounded theory to explain these processes. Key findings include how teachers' tensions and agential moves worked in tandem in the development of a safe and shared place to share discontentment and generate opportunities to form design teams and select issues. Teacher passion and existing resources are factors as influential as considerations for issue relevance. Implications for teacher professional development and research are included

    Obesity-induced insulin resistance in human skeletal muscle is characterised by defective activation of p42/p44 MAP kinase

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    Insulin resistance (IR), an impaired cellular, tissue and whole body response to insulin, is a major pathophysiological defect of type 2 diabetes mellitus. Although IR is closely associated with obesity, the identity of the molecular defect(s) underlying obesity-induced IR in skeletal muscle remains controversial; reduced post-receptor signalling of the insulin receptor substrate 1 (IRS1) adaptor protein and downstream effectors such as protein kinase B (PKB) have previously been implicated. We examined expression and/or activation of a number of components of the insulin-signalling cascade in skeletal muscle of 22 healthy young men (with body mass index (BMI) range, 20–37 kg/m2). Whole body insulin sensitivity (M value) and body composition was determined by the hyperinsulinaemic (40 mU. min−1.m−2.), euglycaemic clamp and by dual energy X-ray absorptiometry (DEXA) respectively. Skeletal muscle (vastus lateralis) biopsies were taken before and after one hour of hyperinsulinaemia and the muscle insulin signalling proteins examined by western blot and immunoprecipitation assay. There was a strong inverse relationship between M-value and BMI. The most striking abnormality was significantly reduced insulin-induced activation of p42/44 MAP kinase, measured by specific assay, in the volunteers with poor insulin sensitivity. However, there was no relationship between individuals' BMI or M-value and protein expression/phosphorylation of IRS1, PKB, or p42/44 MAP kinase protein, under basal or hyperinsulinaemic conditions. In the few individuals with poor insulin sensitivity but preserved p42/44 MAP kinase activation, other signalling defects were evident. These findings implicate defective p42/44 MAP kinase signalling as a potential contributor to obesity-related IR in a non-diabetic population, although clearly multiple signalling defects underlie obesity associated IR

    Mental Models of Soil Management for Food Security in Peri-Urban India

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    Agricultural development during the Green Revolution brought India food sovereignty but food insecurity persists. Increased crop production was promoted without considering the more holistic impact on food security. Scientists, extension agents, and farmers have different perspectives on how soil health relates to food security. Understanding stakeholders’ perspectives is essential to improving extension communication and mitigating consequences. This study uses qualitative interviews to construct mental models of soil health for food security. The study site is a peri-urban watershed, which is currently participating in the Integrated Farmer Participatory Watershed Management Model (IFPWM). Our study details and defines stakeholders’ mental models of soil health, soil nutrient management, soil sodicity, and food security. A triad belief held by farmers shows the strongly perceived causal relationship between soil health, plant health, and human health. Healthy soil produces healthy food and humans that eat such food will be healthy. Scientists only perceive one condition to achieving food security in the community—food quantity. However, all other stakeholders perceived another risk to food security—food quality. Eating poor quality food is perceived as linked to human health problems in the community. This research suggests the importance of including a fifth dimension of food security, cultural acceptability, within agricultural technology development and dissemination

    Impact of rs361072 in the Phosphoinositide 3-Kinase p110β Gene on Whole-Body Glucose Metabolism and Subunit Protein Expression in Skeletal Muscle

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    OBJECTIVE-Phosphoinositide 3-kinase (PI3K) is a major effector in insulin signaling. rs361072, located in the promoter of the gene (PIK3CB) for the p110 beta subunit, has previously been found to be associated with homeostasis model assessment for insulin resistance (HOMA-IR) in obese subjects. The aim was to investigate the influence of rs361072 on in vivo glucose metabolism, skeletal muscle PI3K subunit protein levels, and type 2 diabetes. RESEARCH DESIGN AND METHODS-The functional role of rs361072 was studied in 196 Danish healthy adult twins. Peripheral and hepatic insulin sensitivity was assessed by a euglycemic-hyperinsulinemic clamp. Basal and insulin-stimulated biopsies were taken from the vastus lateralis muscle, and tissue p110 beta and p85 alpha proteins were measured by Western blotting. The genetic association with type 2 diabetes and quantitative metabolic traits was investigated in 9,316 Danes with glucose tolerance ranging from normal to overt type 2 diabetes. RESULTS-While hepatic insulin resistance was similar in the fasting state, carriers of the minor G allele had lower hepatic glucose output (per-allele effect: 16%, P-add = 0.004) during high physiological insulin infusion. rs361072 did not associate with insulin-stimulated peripheral glucose disposal despite a decreased muscle p85 alpha:p110 beta protein ratio (P-add = 0.03) in G allele carriers. No association with HOMA-IR or type 2 diabetes (odds ratio 1.07, P = 0.5) was identified, and obesity did not interact with rs361072 on these traits. CONCLUSIONS-Our study suggests that the minor G allele of PIK3CB rs361072 associates with decreased muscle p85 alpha:p110 beta ratio and lower hepatic glucose production at high plasma insulin levels. However, no impact on type 2 diabetes prevalence was found. Diabetes 59:1108-1112, 201

    CTGF drives autophagy, glycolysis and senescence in cancer-associated fibroblasts via HIF1 activation, metabolically promoting tumor growth

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    Previous studies have demonstrated that loss of caveolin-1 (Cav-1) in stromal cells drives the activation of the TGF-β signaling, with increased transcription of TGF-β target genes, such as connective tissue growth factor (CTGF). In addition, loss of stromal Cav-1 results in the metabolic reprogramming of cancer-associated fibroblasts, with the induction of autophagy and glycolysis. However, it remains unknown if activation of the TGF-β / CTGF pathway regulates the metabolism of cancer-associated fibroblasts. Therefore, we investigated whether CTGF modulates metabolism in the tumor microenvironment. For this purpose, CTGF was overexpressed in normal human fibroblasts or MDA-MB-231 breast cancer cells. Overexpression of CTGF induces HIF-1α-dependent metabolic alterations, with the induction of autophagy/mitophagy, senescence, and glycolysis. Here, we show that CTGF exerts compartment-specific effects on tumorigenesis, depending on the cell-type. In a xenograft model, CTGF overexpressing fibroblasts promote the growth of co-injected MDA-MB-231 cells, without any increases in angiogenesis. Conversely, CTGF overexpression in MDA-MB-231 cells dramatically inhibits tumor growth in mice. Intriguingly, increased extracellular matrix deposition was seen in tumors with either fibroblast or MDA-MB-231 overexpression of CTGF. Thus, the effects of CTGF expression on tumor formation are independent of its extracellular matrix function, but rather depend on its ability to activate catabolic metabolism. As such, CTGF-mediated induction of autophagy in fibroblasts supports tumor growth via the generation of recycled nutrients, whereas CTGF-mediated autophagy in breast cancer cells suppresses tumor growth, via tumor cell self-digestion. Our studies shed new light on the compartment-specific role of CTGF in mammary tumorigenesis, and provide novel insights into the mechanism(s) generating a lethal tumor microenvironment in patients lacking stromal Cav-1. As loss of Cav-1 is a stromal marker of poor clinical outcome in women with primary breast cancer, dissecting the downstream signaling effects of Cav-1 are important for understanding disease pathogenesis, and identifying novel therapeutic targets

    CHEK2 1100delC in patients with metachronous cancers of the breast and the colorectum

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    BACKGROUND: Development of multiple primary tumors is a hallmark of hereditary cancer. At least 1/10 of breast cancers and colorectal cancers occur because of heredity and recently the cell cycle kinase 2, CHEK2 1100delC allele has been identified at a particularly high frequency in families with hereditary breast and colorectal cancer. METHODS: We utilized the Southern Sweden population-based cancer registry to identify women with double primary breast and colorectal cancer and sequenced tumor material in order to assess the contribution of the CHEK2 1100delC to the development of such metachronous tumors. RESULTS: Among the 75 patients successfully analyzed, 2 (2.5%) carried the CHEK2 1100delC allele. which was not significantly different (p = 0.26) from the 1% (3/300) carriers identified in the control group. CONCLUSION: In summary, our data suggest that the CHEK2 1100delC is not a major cause of double primary breast and colorectal cancer in Sweden, which suggests that this patient group should not routinely be screened for the CHEK2 1100delC variant

    Frequency of CHEK2 mutations in a population based, case–control study of breast cancer in young women

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    INTRODUCTION: The cell-cycle checkpoint kinase (CHEK)2 protein truncating mutation 1100delC has been associated with increased risk for breast or prostate cancer. Multiple studies have found an elevated frequency of the 1100delC variant in specific stratifications of breast cancer patients with a family history of the disease, including BRCA1/BRCA2 negative families and families with a history of bilateral disease or male breast cancer. However, the 1100delC mutation has only been investigated in a few population-based studies and none from North America. METHODS: We report here on the frequency of three CHEK2 variants that alter protein function – 1100delC, R145W, and I175T – in 506 cases and 459 controls from a population based, case–control study of breast cancer conducted in young women from western Washington. RESULTS: There was a suggestive enrichment in the 1100delC variant in the cases (1.2%) as compared with the controls (0.4%), but this was based on small numbers of carriers and the differences were not statistically significant. The 1100delC variant was more frequent in cases with a first-degree family history of breast cancer (4.3%; P = 0.02) and slightly enriched in cases with a family history of ovarian cancer (4.4%; P = 0.09). CONCLUSION: The CHEK2 variants are rare in the western Washington population and, based on accumulated evidence across studies, are unlikely to be major breast cancer susceptibility genes. Thus, screening for the 1100delC variant may have limited usefulness in breast cancer prevention programs in the USA

    Theorizing transnational labour markets. A research heuristic based on the new economic sociology

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    Mense-Petermann U. Theorizing transnational labour markets. A research heuristic based on the new economic sociology. Global Networks. 2020;20(3):410-433.In this article, I suggest that transnational labour markets are characterized by their multi‐layered embeddedness, not only in national but also in transnational institutional settings. Hence, the national institutional factors formerly at the centre of sociological labour market theories insufficiently explain the newly emerging transnational labour markets. To account for the full complexity and institutional context of the latter, I propose an inductive theoretical approach to transnational labour markets and develop a research heuristic to instruct empirical studies about particular transnational labour markets and inductive theory building. This heuristic draws on analytical categories as developed by the new economic sociology of markets. The empirical example of the transnational labour market that matches eastern European workers to jobs in the German meat industry serves to illustrate how one can use this heuristic, which reveals some preliminary features of transnational labour markets compared with national ones, as well as some research gaps to be addressed by future studies
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