16,729 research outputs found

    High quality epitaxial ZnSe and the relationship between electron mobility and photoluminescence characteristics

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    High quality epitaxial layers of nominally undoped ZnSe have been grown by metalorganic chemical vapor deposition at low temperature (325 °C) and pressure (30 Torr), using dimethylzinc and hydrogen selenide. All layers were unintentionally doped n type with net carrier concentrations of 6.4×10^(14)–1.5×10^(16) cm^(−3) and exhibited very high mobility at room temperature (up to 500 cm2/V s) as well as at 77 K, where the measured value of 9250 cm^2/V s is the highest so far reported for vapor phase growth. Additional evidence for the high quality of the material is provided by photoluminescence. Experimental results indicate a correlation between the photoluminescence characteristics and the electrical properties that may be useful in assessing the quality of ZnSe films

    Double Secret Protection: Bridging Federal and State Law To Protect Privacy Rights for Telemental and Mobile Health Users

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    Mental health care in the United States is plagued by stigma, cost, and access issues that prevent many people from seeking and continuing treatment for mental health conditions. Emergent technology, however, may offer a solution. Through telemental health, patients can connect with providers remotely—avoiding stigmatizing situations that can arise from traditional healthcare delivery, receiving more affordable care, and reaching providers across geographic boundaries. And with mobile health technology, people can use smart phone applications both to self-monitor their mental health and to communicate with their doctors. But people do not want to take advantage of telemental and mobile health unless their privacy is protected. After evaluating the applicability of current health information privacy law to these new forms of treatment, this Note proposes changes to the federal regime to protect privacy rights for telemental and mobile health users

    Indexing Metric Spaces for Exact Similarity Search

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    With the continued digitalization of societal processes, we are seeing an explosion in available data. This is referred to as big data. In a research setting, three aspects of the data are often viewed as the main sources of challenges when attempting to enable value creation from big data: volume, velocity and variety. Many studies address volume or velocity, while much fewer studies concern the variety. Metric space is ideal for addressing variety because it can accommodate any type of data as long as its associated distance notion satisfies the triangle inequality. To accelerate search in metric space, a collection of indexing techniques for metric data have been proposed. However, existing surveys each offers only a narrow coverage, and no comprehensive empirical study of those techniques exists. We offer a survey of all the existing metric indexes that can support exact similarity search, by i) summarizing all the existing partitioning, pruning and validation techniques used for metric indexes, ii) providing the time and storage complexity analysis on the index construction, and iii) report on a comprehensive empirical comparison of their similarity query processing performance. Here, empirical comparisons are used to evaluate the index performance during search as it is hard to see the complexity analysis differences on the similarity query processing and the query performance depends on the pruning and validation abilities related to the data distribution. This article aims at revealing different strengths and weaknesses of different indexing techniques in order to offer guidance on selecting an appropriate indexing technique for a given setting, and directing the future research for metric indexes

    Organization of the Smallest Eukaryotic Spindle

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    In metazoans, plants, and fungi, the spindle checkpoint delays mitosis until each chromosome is attached to one or more of its own kinetochore microtubules (kMTs). Some unicellular eukaryotes, however, have been reported to have fewer kMTs than chromosomes. If this is the case, it is unclear how the spindle checkpoint could be satisfied. In the vast majority of the previous studies, mitotic cells were chemically fixed at room temperature, but this does not always preserve dynamic and/or small structures like spindle MTs and kinetochores. Indeed, later higher-resolution studies have reversed some earlier claims. Here we show that in Ostreococcus tauri (the smallest eukaryote known), mitosis does involve fewer spindle microtubules than chromosomes. O. tauri cultures were enriched for mitotic cells, high-pressure frozen, and then imaged in 3D both in plastic and in a near-native ("frozen-hydrated") state through electron tomography. Mitotic cells have a distinctive intranuclear heterochromatin-free "spindle tunnel" with approximately four short and occasionally one long, incomplete (unclosed) microtubule at each end of the spindle tunnel. Because other aspects of O. tauri’s spindle checkpoint seem typical, these data suggest that O. tauri’s 20 chromosomes are physically linked and segregated as just one or a small number of groups

    Pharmacological Inhibition of CDK8 in Triple-Negative Breast Cancer Cell line MDA-MB-468 Increases E2F1 Protein, Induces Phosphorylation of STAT3 and Apoptosis

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    Cyclin-dependent kinase 8 (CDK8) has been identified as a colon cancer oncogene. Since this initial observation, CDK8 has been implicated as a potential driver of other cancers including acute myelogenous leukemia (AML) and some breast cancers. Here, we observed different biological responses to CDK8 inhibition among colon cancer cell lines and the triple-negative breast cancer (TNBC) cell line MDA-MB-468. When treated with CDK8 inhibitor 4, all treated cell lines responded with decreased cell viability and increased apoptosis. In the MDA-MB-468 cell line, the decrease in cell viability was dependent on increased phosphorylation of signal transducer and activator of transcription 3 (STAT3), which is not observed in the colon cancer cell lines. Furthermore, increased STAT3 phosphorylation in 4 treated MDA-MB-468 cells was dependent on increased transcription factor E2F1 protein. These results are consistent with previous reports of exogenous expression of E2F1-induced apoptosis in MDA-MB-468 cells

    Metabolic predispositions and increased risk of colorectal adenocarcinoma by anatomical locations: a large population-based cohort study in Norway

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    Whether different definitions of metabolic syndrome (MetS) are differently associated with colorectal adenocarcinoma (CA) by anatomical location is unclear. A population-based cohort study, the Cohort of Norway (CONOR) Study, was conducted in Norway from 1995 to 2010. Anthropometric measurements, blood samples, and lifestyle data were collected at recruitment. CAs were identified through linkage to the Norwegian Cancer Register. A composite index of MetS as defined by the International Diabetes Federation (IDF) or/and the National Cholesterol Education Program's Adult Treatment Panel III (ATP III) and single components of MetS, including anthropometric factors, blood pressure, lipids, triglycerides, and glucose, were analyzed. Cox proportional hazards regression was performed to estimate hazard ratios and 95% confidence intervals. Significant associations between single MetS components and CA, except for reduced high-density lipoprotein cholesterol and nonfasting glucose levels, were observed. MetS defined by 2 criteria separately showed a similar association with CA in general, and MetS defined by both the IDF and ATP III showed consistent results. Stronger associations were observed in the proximal colon among men (IDF: hazard ratio (HR) = 1.51, 95% confidence interval (CI): 1.24, 1.84; ATP III: HR = 1.40, 95% CI: 1.15, 1.70) and in the rectum among women (IDF: HR = 1.42, 95% CI: 1.07, 1.89; ATP III: HR = 1.43, 95% CI: 1.08, 1.90).Swedish Society of MedicineKarolinska InstitutetSwedish Research CouncilAccepte

    Correlated flares in models of a magnetized "canopy"

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    A model of the Lu-Hamilton kind is applied to the study of critical behavior of the magnetized solar atmosphere. The main novelty is that its driving is done via sources undergoing a diffusion. This mimics the effect of a virtual turbulent substrate forcing the system. The system exhibits power-law statistics not only in the size of the flares, but also in the distribution of the waiting times.Comment: 5 pages + 9 figures, Accepted to Physica
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