2,381 research outputs found

    Ultrasonically assisted machining of Titanium alloys

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    In this chapter we discuss the nuances of a non-conventional machining technique known as ultrasonically assisted machining, which has been used to demonstrate tractable benefits in the machining of titanium alloys. We also demonstrate how further improvements may be achieved by combining this machining technique with the well known advantages of hot machining in metals and alloys

    Visual Reasoning with Multi-hop Feature Modulation

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    Recent breakthroughs in computer vision and natural language processing have spurred interest in challenging multi-modal tasks such as visual question-answering and visual dialogue. For such tasks, one successful approach is to condition image-based convolutional network computation on language via Feature-wise Linear Modulation (FiLM) layers, i.e., per-channel scaling and shifting. We propose to generate the parameters of FiLM layers going up the hierarchy of a convolutional network in a multi-hop fashion rather than all at once, as in prior work. By alternating between attending to the language input and generating FiLM layer parameters, this approach is better able to scale to settings with longer input sequences such as dialogue. We demonstrate that multi-hop FiLM generation achieves state-of-the-art for the short input sequence task ReferIt --- on-par with single-hop FiLM generation --- while also significantly outperforming prior state-of-the-art and single-hop FiLM generation on the GuessWhat?! visual dialogue task.Comment: In Proc of ECCV 201

    Open defecation and childhood stunting in India: an ecological analysis of new data from 112 districts.

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    Poor sanitation remains a major public health concern linked to several important health outcomes; emerging evidence indicates a link to childhood stunting. In India over half of the population defecates in the open; the prevalence of stunting remains very high. Recently published data on levels of stunting in 112 districts of India provide an opportunity to explore the relationship between levels of open defecation and stunting within this population. We conducted an ecological regression analysis to assess the association between the prevalence of open defecation and stunting after adjustment for potential confounding factors. Data from the 2011 HUNGaMA survey was used for the outcome of interest, stunting; data from the 2011 Indian Census for the same districts was used for the exposure of interest, open defecation. After adjustment for various potential confounding factors--including socio-economic status, maternal education and calorie availability--a 10 percent increase in open defecation was associated with a 0.7 percentage point increase in both stunting and severe stunting. Differences in open defecation can statistically account for 35 to 55 percent of the average difference in stunting between districts identified as low-performing and high-performing in the HUNGaMA data. In addition, using a Monte Carlo simulation, we explored the effect on statistical power of the common practice of dichotomizing continuous height data into binary stunting indicators. Our simulation showed that dichotomization of height sacrifices statistical power, suggesting that our estimate of the association between open defecation and stunting may be a lower bound. Whilst our analysis is ecological and therefore vulnerable to residual confounding, these findings use the most recently collected large-scale data from India to add to a growing body of suggestive evidence for an effect of poor sanitation on human growth. New intervention studies, currently underway, may shed more light on this important issue

    Human α2β1HI CD133+VE epithelial prostate stem cells express low levels of active androgen receptor

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    Stem cells are thought to be the cell of origin in malignant transformation in many tissues, but their role in human prostate carcinogenesis continues to be debated. One of the conflicts with this model is that cancer stem cells have been described to lack androgen receptor (AR) expression, which is of established importance in prostate cancer initiation and progression. We re-examined the expression patterns of AR within adult prostate epithelial differentiation using an optimised sensitive and specific approach examining transcript, protein and AR regulated gene expression. Highly enriched populations were isolated consisting of stem (α(2)β(1)(HI) CD133(+VE)), transiently amplifying (α(2)β(1)(HI) CD133(-VE)) and terminally differentiated (α(2)β(1)(LOW) CD133(-VE)) cells. AR transcript and protein expression was confirmed in α(2)β(1)(HI) CD133(+VE) and CD133(-VE) progenitor cells. Flow cytometry confirmed that median (±SD) fraction of cells expressing AR were 77% (±6%) in α(2)β(1)(HI) CD133(+VE) stem cells and 68% (±12%) in α(2)β(1)(HI) CD133(-VE) transiently amplifying cells. However, 3-fold lower levels of total AR protein expression (peak and median immunofluorescence) were present in α(2)β(1)(HI) CD133(+VE) stem cells compared with differentiated cells. This finding was confirmed with dual immunostaining of prostate sections for AR and CD133, which again demonstrated low levels of AR within basal CD133(+VE) cells. Activity of the AR was confirmed in prostate progenitor cells by the expression of low levels of the AR regulated genes PSA, KLK2 and TMPRSS2. The confirmation of AR expression in prostate progenitor cells allows integration of the cancer stem cell theory with the established models of prostate cancer initiation based on a functional AR. Further study of specific AR functions in prostate stem and differentiated cells may highlight novel mechanisms of prostate homeostasis and insights into tumourigenesis

    Underwater Leidenfrost nanochemistry for creation of size-tailored zinc peroxide cancer nanotherapeutics

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    The dynamic underwater chemistry seen in nature is inspiring for the next generation of eco-friendly nanochemistry. In this context, green synthesis of size-tailored nanoparticles in a facile and scalable manner via a dynamic process is an interesting challenge. Simulating the volcano-induced dynamic chemistry of the deep ocean, here we demonstrate the Leidenfrost dynamic chemistry occurring in an underwater overheated confined zone as a new tool for customized creation of nanoclusters of zinc peroxide. The hydrodynamic nature of the phenomenon ensures eruption of the nanoclusters towards a much colder region, giving rise to growth of monodisperse, size-tailored nanoclusters. Such nanoparticles are investigated in terms of their cytotoxicity on suspension and adherent cells to prove their applicability as cancer nanotherapeutics. Our research can pave the way for employment of the dynamic green nanochemistry in facile, scalable fabrication of size-tailored nanoparticles for biomedical applications.Peer reviewe

    VEZF1 elements mediate protection from DNA methylation

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    There is growing consensus that genome organization and long-range gene regulation involves partitioning of the genome into domains of distinct epigenetic chromatin states. Chromatin insulator or barrier elements are key components of these processes as they can establish boundaries between chromatin states. The ability of elements such as the paradigm β-globin HS4 insulator to block the range of enhancers or the spread of repressive histone modifications is well established. Here we have addressed the hypothesis that a barrier element in vertebrates should be capable of defending a gene from silencing by DNA methylation. Using an established stable reporter gene system, we find that HS4 acts specifically to protect a gene promoter from de novo DNA methylation. Notably, protection from methylation can occur in the absence of histone acetylation or transcription. There is a division of labor at HS4; the sequences that mediate protection from methylation are separable from those that mediate CTCF-dependent enhancer blocking and USF-dependent histone modification recruitment. The zinc finger protein VEZF1 was purified as the factor that specifically interacts with the methylation protection elements. VEZF1 is a candidate CpG island protection factor as the G-rich sequences bound by VEZF1 are frequently found at CpG island promoters. Indeed, we show that VEZF1 elements are sufficient to mediate demethylation and protection of the APRT CpG island promoter from DNA methylation. We propose that many barrier elements in vertebrates will prevent DNA methylation in addition to blocking the propagation of repressive histone modifications, as either process is sufficient to direct the establishment of an epigenetically stable silent chromatin stat

    Indoor solid fuel use and tuberculosis in China: a matched case-control study

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    <p>Abstract</p> <p>Background</p> <p>China ranks second among the 22 high burden countries for tuberculosis. A modeling exercise showed that reduction of indoor air pollution could help advance tuberculosis control in China. However, the association between indoor air pollution and tuberculosis is not yet well established. A case control study was conducted in Anhui, China to investigate whether use of solid fuel is associated with tuberculosis.</p> <p>Methods</p> <p>Cases were new sputum smear positive tuberculosis patients. Two controls were selected from the neighborhood of each case matched by age and sex using a pre-determined procedure. A questionnaire containing demographic information, smoking habits and use of solid fuel for cooking or heating was used for interview. Solid fuel (coal and biomass) included coal/lignite, charcoal, wood, straw/shrubs/grass, animal dung, and agricultural crop residue. A household that used solid fuel either for cooking and (/or) heating was classified as exposure to combustion of solid fuel (indoor air pollution). Odds ratios and their corresponding 95% confidence limits for categorical variables were determined by Mantel-Haenszel estimate and multivariate conditional logistic regression.</p> <p>Results</p> <p>There were 202 new smear positive tuberculosis cases and 404 neighborhood controls enrolled in this study. The proportion of participants who used solid fuels for cooking was high (73.8% among cases and 72.5% among controls). The majority reported using a griddle stove (85.2% among cases and 86.7% among controls), had smoke removed by a hood or chimney (92.0% among cases and 92.8% among controls), and cooked in a separate room (24.8% among cases and 28.0% among controls) or a separate building (67.8% among cases and 67.6% among controls). Neither using solid fuel for cooking (odds ratio (OR) 1.08, 95% CI 0.62-1.87) nor using solid fuel for heating (OR 1.04, 95% CI 0.54-2.02) was significantly associated with tuberculosis. Determinants significantly associated with tuberculosis were household tuberculosis contact (adjusted OR, 27.23, 95% CI 8.19-90.58) and ever smoking tobacco (adjusted OR 1.64, 96% CI 1.01-2.66).</p> <p>Conclusion</p> <p>In a population where the majority had proper ventilation in cooking places, the association between use of solid fuel for cooking or for heating and tuberculosis was not statistically significant.</p

    Epigenetic regulation of PPARGC1A in human type 2 diabetic islets and effect on insulin secretion

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    Aims/hypothesis Insulin secretion in pancreatic islets is dependent upon mitochondrial function and production of ATP. The transcriptional coactivator peroxisome proliferator activated receptor gamma coactivator-1 alpha (protein PGC-1 alpha; gene PPARGC1A) is a master regulator of mitochondrial genes and its expression is decreased and related to impaired oxidative phosphorylation in muscle from patients with type 2 diabetes. Whether it plays a similar role in human pancreatic islets is not known. We therefore investigated if PPARGC1A expression is altered in islets from patients with type 2 diabetes and whether this expression is influenced by genetic (PPARGC1A Gly482Ser polymorphism) and epigenetic (DNA methylation) factors. We also tested if experimental downregulation of PPARGC1A expression in human islets influenced insulin secretion. Methods The PPARGC1A Gly482Ser polymorphism was genotyped in human pancreatic islets from 48 non-diabetic and 12 type 2 diabetic multi-organ donors and related to PPARGC1A mRNA expression. DNA methylation of the PPARGC1A promoter was analysed in pancreatic islets from ten type 2 diabetic and nine control donors. Isolated human islets were transfected with PPARGC1A silencing RNA (siRNA). Results PPARGC1A mRNA expression was reduced by 90% (p < 0.005) and correlated with the reduction in insulin secretion in islets from patients with type 2 diabetes. After downregulation of PPARGC1A expression in human islets by siRNA, insulin secretion was reduced by 41% (p <= 0. 01). We were able to ascribe reduced PPARGC1A expression in islets to both genetic and epigenetic factors, i.e. a common PPARGC1A Gly482Ser polymorphism was associated with reduced PPARGC1A mRNA expression (p < 0.00005) and reduced insulin secretion (p < 0.05). In support of an epigenetic influence, the PPARGC1A gene promoter showed a twofold increase in DNA methylation in diabetic islets compared with non-diabetic islets (p < 0.04). Conclusions/Interpretation We have shown for the first time that PPARGC1A might be important in human islet insulin secretion and that expression of PPARGC1A in human islets can be regulated by both genetic and epigenetic factors

    Mini-open anterior spine surgery for anterior lumbar diseases

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    Minimally invasive surgeries including endoscopic surgery and mini-open surgery are current trend of spine surgery, and its main advantages are shorter recovery time and cosmetic benefits, etc. However, mini-open surgery is easier and less technique demanding than endoscopic surgery. Besides, anterior spinal fusion is better than posterior spinal fusion while considering the physiological loading, back muscle function, etc. Therefore, we aimed to introduce the modified “mini-open anterior spine surgery” (MOASS) and to evaluate the feasibility, effectiveness and safety in the treatment of various anterior lumbar diseases with this technique. A total of 61 consecutive patients (46 female, 15 male; mean age 58.2 years) from 1997 to 2004 were included in this study, with an average follow-up of 24–52 (mean 43) months. The disease entities included vertebral fracture (20), failed back surgery (13), segmental instability or spondylolisthesis (10), infection (8), herniated disc (5), undetermined lesion for biopsy (4), and hemivertebra (1). Lesions involved 13 cases at T12–L1, 18 at L1–L2, 18 at L2–L3, 22 at L3–L4 and 11 at L4–L5 levels. All patients received a single stage anterior-only procedure for their anterior lumbar disease. We used the subjective clinical results, Oswestry disability index, fusion rate, and complications to evaluate our clinical outcome. Most patients (91.8%) were subjectively satisfied with the surgery and had good-to-excellent outcomes. Mean operation time was 85 (62–124) minutes, and mean blood loss was 136 (minimal-250) ml in the past 6 years. Hospital stay ranged from 4–26 (mean 10.6) days. Nearly all cases had improved back pain (87%), physical function (90%) and life quality (85%). Most cases (95%) achieved solid or probable solid bony fusion. There were no major complications. Therefore, MOASS is feasible, effective and safe for patients with various anterior lumbar diseases
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