1,981 research outputs found

    Modeling of droplet breakup in a microfluidic T--shaped junction with a phase--field model

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    A phase--field method is applied to the modeling of flow and breakup of droplets in a T--shaped junction in the hydrodynamic regime where capillary and viscous stresses dominate over inertial forces, which is characteristic of microfluidic devices. The transport equations are solved numerically in the three--dimensional geometry, and the dependence of the droplet breakup on the flow rates, surface tension and viscosities of the two components is investigated in detail. The model reproduces quite accurately the phase diagram observed in experiments performed with immiscible fluids. The critical capillary number for droplet breakup depends on the viscosity contrast, with a trend which is analogous to that observed for free isolated droplets in hyperbolic flow

    Maternal residential pesticide use and risk of childhood leukemia in Costa Rica.

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    Evidence suggests that early-life exposure to pesticides inside the home may be associated with childhood leukemia, however data from Latin American countries are limited. We examined whether self-reported maternal residential pesticide use and nearby pesticide applications-before and after child's birth-were associated with acute lymphoblastic leukemia (ALL) in the Costa Rican Childhood Leukemia Study (CRCLS), a population-based case-control study (2001-2003). Cases (n = 251 ALL) were diagnosed between 1995 and 2000 (age <15 years at diagnosis) and were identified through the Costa Rican Cancer Registry and National Children's Hospital. Population controls (n = 577) were drawn from the National Birth Registry. We fitted unconditional logistic regression models adjusted for child sex, birth year, and socioeconomic status to estimate the exposure-outcome associations and also stratified by child sex. We observed that self-reported maternal insecticide use inside the home in the year before pregnancy, during pregnancy, and while breastfeeding was associated with increased odds of ALL among boys [adjusted Odds Ratio (aOR) = 1.63 (95% confidence interval [95% CI]: 1.05-2.53), 1.75 (1.13-2.73), and 1.75 (1.12-2.73), respectively. We also found evidence of exposure-response relationships between more frequent maternal insecticide use inside the home and increased odds of ALL among boys and girls combined. Maternal report of pesticide applications on farms or companies near the home during pregnancy and at any time period were also associated with ALL. Our study in Costa Rica highlights the need for education to minimize pesticide exposures inside and around the home, particularly during pregnancy and breastfeeding

    Primary osteoblast-like cells from patients with end-stage kidney disease reflect gene expression, proliferation, and mineralization characteristics ex vivo.

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    Osteocytes regulate bone turnover and mineralization in chronic kidney disease. As osteocytes are derived from osteoblasts, alterations in osteoblast function may regulate osteoblast maturation, osteocytic transition, bone turnover, and skeletal mineralization. Thus, primary osteoblast-like cells were cultured from bone chips obtained from 24 pediatric ESKD patients. RNA expression in cultured cells was compared with RNA expression in cells from healthy individuals, to RNA expression in the bone core itself, and to parameters of bone histomorphometry. Proliferation and mineralization rates of patient cells were compared with rates in healthy control cells. Associations were observed between bone osteoid accumulation, as assessed by bone histomorphometry, and bone core RNA expression of osterix, matrix gla protein, parathyroid hormone receptor 1, and RANKL. Gene expression of osteoblast markers was increased in cells from ESKD patients and signaling genes including Cyp24A1, Cyp27B1, VDR, and NHERF1 correlated between cells and bone cores. Cells from patients with high turnover renal osteodystrophy proliferated more rapidly and mineralized more slowly than did cells from healthy controls. Thus, primary osteoblasts obtained from patients with ESKD retain changes in gene expression ex vivo that are also observed in bone core specimens. Evaluation of these cells in vitro may provide further insights into the abnormal bone biology that persists, despite current therapies, in patients with ESKD

    Фільтраційні справи радянських громадян, примусово вивезених до Німеччина в роки Великої Вітчизняної війни, як історичне джерело

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    We ask how incumbent car manufacturers and their political coalitions changed their political strategy with respect to the Californian zero emission vehicle mandate over the period 2000-2013. Building on the Corporate Political Activities literature we conceptualize firms' political strategies and their underlying tactics and actions. Our longitudinal case study builds on a dataset comprising governmental reports, documents, and public hearing transcripts, letters from industry, and complementary interviews with stakeholders. We find that car manufacturers became less defensive over time and more proactive and compliant in their political strategies towards the zero emission vehicle mandate. Car manufacturers' coalitions on the other hand, remain relatively defensive in their political actions as they continue to do the manufacturers' "dirty work". We provide insights in the Corporate Political Activities used to influence policymakers. To deal with industry opposition to policy interventions, our research suggests that policy makers might focus their interaction with industry on individual firms instead of industry associations, craft policies that stimulate competition between firms to break apart their closed industry front, and complement technology-forcing policies with demand-pull initiatives

    Inferring the time-dependent complex Ginzburg-Landau equation from modulus data

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    We present a formalism for inferring the equation of evolution of a complex wave field that is known to obey an otherwise unspecified (2+1)-dimensional time-dependent complex Ginzburg-Landau equation, given field moduli over three closely-spaced planes. The phase of the complex wave field is retrieved via a non-interferometric method, and all terms in the equation of evolution are determined using only the magnitude of the complex wave field. The formalism is tested using simulated data for a generalized nonlinear system with a single-component complex wave field. The method can be generalized to multi-component complex fields.Comment: 9 pages, 9 figure

    Automatic muscle elongation measurement during shoulder arthroplasty planning

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    Adequate deltoid and rotator cuff lengthening in total shoulder arthroplasty (TSA) is crucial to maximize the postoperative functional outcome and to avoid complications (La¨dermann et al., 2014). Hence surgeons and patients could benefit from including muscle length information in preoperative planning software. Although different methods have been introduced to automatically indicate patient-specific muscle attachment and wrapping points (Kaptein & van der Helm, 2004; Marra et al., 2015), the definition of a fast and accurate workflow is still a challenge, due to the large variability in bone shapes. Statistical shape modelling (SSM) has recently been used to automatically indicate landmark on target bones (Plessers et al., 2018). This method is less dependent on shape variability and could overcome the aforementioned limitation in accuracy. Therefore, the goal of this study is to develop and evaluate the accuracy of a novel automatic method for measuring deltoid and rotator cuff elongation during preoperative planning of shoulder arthroplasty, based on a statistical shape modelling approach

    Molecular diagnostics of gliomas: state of the art

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    Modern neuropathology serves a key function in the multidisciplinary management of brain tumor patients. Owing to the recent advancements in molecular neurooncology, the neuropathological assessment of brain tumors is no longer restricted to provide information on a tumor’s histological type and malignancy grade, but may be complemented by a growing number of molecular tests for clinically relevant tissue-based biomarkers. This article provides an overview and critical appraisal of the types of genetic and epigenetic aberrations that have gained significance in the molecular diagnostics of gliomas, namely deletions of chromosome arms 1p and 19q, promoter hypermethylation of the O6-methylguanine-methyl-transferase (MGMT) gene, and the mutation status of the IDH1 and IDH2 genes. In addition, the frequent oncogenic aberration of BRAF in pilocytic astrocytomas may serve as a novel diagnostic marker and therapeutic target. Finally, this review will summarize recent mechanistic insights into the molecular alterations underlying treatment resistance in malignant gliomas and outline the potential of genome-wide profiling approaches for increasing our repertoire of clinically useful glioma markers
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