817 research outputs found

    The peroxisome: still a mysterious organelle.

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    More than half a century of research on peroxisomes has revealed unique features of this ubiquitous subcellular organelle, which have often been in disagreement with existing dogmas in cell biology. About 50 peroxisomal enzymes have so far been identified, which contribute to several crucial metabolic processes such as beta-oxidation of fatty acids, biosynthesis of ether phospholipids and metabolism of reactive oxygen species, and render peroxisomes indispensable for human health and development. It became obvious that peroxisomes are highly dynamic organelles that rapidly assemble, multiply and degrade in response to metabolic needs. However, many aspects of peroxisome biology are still mysterious. This review addresses recent exciting discoveries on the biogenesis, formation and degradation of peroxisomes, on peroxisomal dynamics and division, as well as on the interaction and cross talk of peroxisomes with other subcellular compartments. Furthermore, recent advances on the role of peroxisomes in medicine and in the identification of novel peroxisomal proteins are discussed.Supported by the German Research Foundation (DFG) (SCHR 518/6-1) and the Portuguese Foundation for Science and Technology (FCT) (PTDC/BIA-BCM/71932/2006)

    Declining incidence of esophageal cancer in the Turkmen Plain, eastern part of the Caspian Littoral of Iran: A retrospective cancer surveillance

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    Background: Previous studies have shown that upper gastrointestinal cancers are the most common cancers in Caspian Littoral, and rate of esophageal cancer (EC) in Iranian Turkmens residing in the Eastern part of littoral are among the highest in the world. Our aim was to reassess the rate 30 years later and following socioeconomic changes in the region. Methods: A comprehensive retrospective search was undertaken to find all new cancer cases during the 1996-2000 period. Diagnosis of cancer was based on histopathological reports in 68.2, clinical and/or radiological evidence in 29.7 and death certificate only (DCO) in 2.1 of the cases. Results: A total of 5143 new cancer cases were registered of whom 3063 (59.6) were males. The median (IQR) age was 60 (44-69) years. Age-standardized rates (ASR) for all cancers in males and females were 134.7 and 104.5 per 100,000, respectively. Based on ASR, the top five common cancers in males (excluding skin cancer) were cancers of esophagus (43.4), stomach (27.8), colorectal (10.7), bladder (7.8) and oral cavity (6.3), while in females cancer of esophagus (36.3) was followed by cancers of breast (15.7), stomach (8.3) colorectal (6.6) and cervix (3.6). Conclusion: We conclude that EC incidence rate has decreased to less than half the rate reported 30 years ago, while the incidence rates of colorectal and breast cancers have increased significantly. © 2006 International Society for Preventive Oncology. Published by Elsevier Ltd. All rights reserved

    Diffusing-wave spectroscopy in a standard dynamic light scattering setup

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    Diffusing-wave spectroscopy (DWS) extends dynamic light scattering measurements to samples with strong multiple scattering. DWS treats the transport of photons through turbid samples as a diffusion process, thereby making it possible to extract the dynamics of scatterers from measured correlation functions. The analysis of DWS data requires knowledge of the path length distribution of photons traveling through the sample. While for flat sample cells this path length distribution can be readily calculated and expressed in analytical form; no such expression is available for cylindrical sample cells. DWS measurements have therefore typically relied on dedicated setups that use flat sample cells. Here we show how DWS measurements, in particular DWS-based microrheology measurements, can be performed in standard dynamic light scattering setups that use cylindrical sample cells. To do so we perform simple random-walk simulations that yield numerical predictions of the path length distribution as a function of both the transport mean free path and the detection angle. This information is used in experiments to extract the mean-square displacement of tracer particles in the material, as well as the corresponding frequency-dependent viscoelastic response. An important advantage of our approach is that by performing measurements at different detection angles, the average path length through the sample can be varied. For measurements performed on a single sample cell, this gives access to a wider range of length and time scales than obtained in a conventional DWS setup. Such angle-dependent measurements also offer an important consistency check, as for all detection angles the DWS analysis should yield the same tracer dynamics, even though the respective path length distributions are very different. We validate our approach by performing measurements both on aqueous suspensions of tracer particles and on solidlike gelatin samples, for which we find our DWS-based microrheology data to be in good agreement with rheological measurements performed on the same samples

    Decoding steady-state visual evoked potentials from electrocorticography

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    We report on a unique electrocorticography (ECoG) experiment in which Steady-State Visual Evoked Potentials (SSVEPs) to frequency-and phase-tagged stimuli were recorded from a large subdural grid covering the entire right occipital cortex of a human subject. The paradigm is popular in EEG-based Brain Computer Interfacing where selectable targets are encoded by different frequency-and/or phase-tagged stimuli. We compare the performance of two state-of-the-art SSVEP decoders on both ECoG-and scalp-recorded EEG signals, and show that ECoG-based decoding is more accurate for very short stimulation lengths (i.e., less than 1 s). Furthermore, whereas the accuracy of scalp-EEG decoding bene fi ts from a multi-electrode approach, to address interfering EEG responses and noise, ECoG decoding enjoys only a marginal improvement as even a single electrode, placed over the posterior part of the primary visual cortex, seems to suf fi ce. This study shows, for the fi rst time, that EEG-based SSVEP decoders can in principle be applied to ECoG, and can be expected to yield faster decoding speeds using less electrodes

    Reproductive factors and risk of esophageal squamous cell carcinoma in northern Iran: A case-control study in a high-risk area and literature review

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    Several epidemiologic studies have suggested an inverse association between female reproductive factors and the risk of esophageal squamous cell carcinoma (ESCC), but the evidence is not conclusive. We examined the association of the number of pregnancies, live births, and miscarriages/stillbirths in women and the association of the number of children in both sexes with the risk of ESCC in Golestan Province, a high-risk area in Iran. Data from 297 histopathologically confirmed ESCC cases (149 women) and 568 controls (290 women) individually matched to cases for age, sex, and neighborhood of residence were included in this analysis. Conditional logistic regression was used to calculate odds ratios (ORs) and the corresponding 95% confidence intervals (CIs). The average numbers of live births and miscarriages/stillbirths among the controls were 8.2 and 0.8, respectively. Women with six or more live births were at ∼1/3 the risk of ESCC as those with 0-3 live births; the OR (95% CI) for having 6-7 live births was 0.33 (0.12-0.92). In contrast, the number of miscarriages/stillbirths was associated with an increase in the risk of ESCC. The OR (95% CI) for at least three versus no miscarriages/stillbirths was 4.43 (2.11-9.33). The number of children in women was suggestive of an inverse association with ESCC, but this association was not statistically significant; in men, no association was observed. The findings of this study support a protective influence of female hormonal factors on the risk of ESCC. However, further epidemiological and mechanistic studies are required to prove a protective association. © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins

    Global sodium consumption and death from cardiovascular causes.

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    To access publisher's full text version of this article click on the hyperlink at the bottom of the pageHigh sodium intake increases blood pressure, a risk factor for cardiovascular disease, but the effects of sodium intake on global cardiovascular mortality are uncertain.We collected data from surveys on sodium intake as determined by urinary excretion and diet in persons from 66 countries (accounting for 74.1% of adults throughout the world), and we used these data to quantify the global consumption of sodium according to age, sex, and country. The effects of sodium on blood pressure, according to age, race, and the presence or absence of hypertension, were calculated from data in a new meta-analysis of 107 randomized interventions, and the effects of blood pressure on cardiovascular mortality, according to age, were calculated from a meta-analysis of cohorts. Cause-specific mortality was derived from the Global Burden of Disease Study 2010. Using comparative risk assessment, we estimated the cardiovascular effects of current sodium intake, as compared with a reference intake of 2.0 g of sodium per day, according to age, sex, and country.In 2010, the estimated mean level of global sodium consumption was 3.95 g per day, and regional mean levels ranged from 2.18 to 5.51 g per day. Globally, 1.65 million annual deaths from cardiovascular causes (95% uncertainty interval [confidence interval], 1.10 million to 2.22 million) were attributed to sodium intake above the reference level; 61.9% of these deaths occurred in men and 38.1% occurred in women. These deaths accounted for nearly 1 of every 10 deaths from cardiovascular causes (9.5%). Four of every 5 deaths (84.3%) occurred in low- and middle-income countries, and 2 of every 5 deaths (40.4%) were premature (before 70 years of age). The rate of death from cardiovascular causes associated with sodium intake above the reference level was highest in the country of Georgia and lowest in Kenya.In this modeling study, 1.65 million deaths from cardiovascular causes that occurred in 2010 were attributed to sodium consumption above a reference level of 2.0 g per day. (Funded by the Bill and Melinda Gates Foundation.).Bill and Melinda Gates Foundatio

    The peroxisome: an update on mysteries 2.0

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    This is the final version of the article. Available from Springer Verlag via the DOI in this record.Peroxisomes are key metabolic organelles, which contribute to cellular lipid metabolism, e.g. the β-oxidation of fatty acids and the synthesis of myelin sheath lipids, as well as cellular redox balance. Peroxisomal dysfunction has been linked to severe metabolic disorders in man, but peroxisomes are now also recognised as protective organelles with a wider significance in human health and potential impact on a large number of globally important human diseases such as neurodegeneration, obesity, cancer, and age-related disorders. Therefore, the interest in peroxisomes and their physiological functions has significantly increased in recent years. In this review, we intend to highlight recent discoveries, advancements and trends in peroxisome research, and present an update as well as a continuation of two former review articles addressing the unsolved mysteries of this astonishing organelle. We summarise novel findings on the biological functions of peroxisomes, their biogenesis, formation, membrane dynamics and division, as well as on peroxisome-organelle contacts and cooperation. Furthermore, novel peroxisomal proteins and machineries at the peroxisomal membrane are discussed. Finally, we address recent findings on the role of peroxisomes in the brain, in neurological disorders, and in the development of cancer.This work was supported by the Biotechnology and Biological Sciences Research Council (BB/K006231/1, BB/N01541X/1) and MRC CiC 08135, University of Exeter (to M.S.). M.I. is supported by the German Research Foundation (DFG grant 397476530) and MEAMEDMA Anschubförderung, Medical Faculty Mannheim, University of Heidelberg

    Validity and reliability of a new food frequency questionnaire compared to 24h recalls and biochemical measurements: Pilot phase of Golestan cohort study of esophageal cancer

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    Background: A pilot study was carried out to evaluate validity and reproducibility of a food frequency questionnaire (FFQ), which was designed to be used in a prospective cohort study in a population at high risk for esophageal cancer in northern Iran. Methods: The FFQ was administered four times to 131 subjects, aged 35-65 years, of both sexes. Twelve 24-h dietary recalls for two consecutive days were administered monthly during 1 year and used as a reference method. The excretion of nitrogen was measured on four 24-h urine samples, and plasma levels of β-carotene, retinol, vitamin C and α-tocopherol was measured from two time points. Relative validity of FFQ and 24-h diet recall was assessed by comparing nutrient intake derived from both methods with the urinary nitrogen and plasma levels of β-carotene, retinol, vitamin C and α-tocopherol. Results: Correlation coefficients comparing energy and nutrients intake based on the mean of the four FFQ and the mean of twelve 24-h diet recalls were 0.75 for total energy, 0.75 for carbohydrates, 0.76 for proteins and 0.65 for fat. Correlation coefficients between the FFQ-based intake and serum levels of β-carotene, retinol, vitamin C and vitamin E/α-tocopherol were 0.37, 0.32, 0.35 and 0.06, respectively. Correlation coefficients between urinary nitrogen and FFQ-based protein intake ranged from 0.23 to 0.35. Intraclass correlation coefficients used to measure reproducibility of FFQ ranged from 0.66 to 0.89. Conclusion: We found that the FFQ provides valid and reliable measurements of habitual intake for energy and most of the nutrients studied. © 2006 Nature Publishing Group. All rights reserved

    Prediction of Rotor Position at Standstill and Flying Shaft Conditions in Switched Reluctance Machines

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    Development of a reliable, smooth, and precise position sensor less startup routine is an integral part of the Switched Reluctance Machine (SRM) control. the proposed sensor less startup method presented in this paper represents high grade performance and does not require additional hardware or memory. Further, the proposed sensor less technique is extended to flying shaft conditions. These capabilities are highly demanded by automotive applications such as starter/alternator and electric power steering systems. an assessment of the impact of motor parameters and diagnostic signal measurement on the quality of the sensor less startup method is also included. This will help practicing engineers to make judicious selections for implementation of the proposed technique. Experimental and theoretical results are included to validate our claims

    Elucidation of big data analytics in banking : a four-stage Delphi study

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    Purpose In today's networked business environment, a huge amount of data is being generated and processed in different industries, which banking is amongst the most important ones. The aim of this study is to understand and prioritize strategic applications, main drivers, and key challenges of implementing big data analytics in banks. Design/methodology/approach To take advantage of experts' viewpoints, the authors designed and implemented a four-round Delphi study. Totally, 25 eligible experts have contributed to this survey in collecting and analyzing the data. Findings The results revealed that the most important applications of big data in banks are “fraud detection” and “credit risk analysis.” The main drivers to start big data endeavors are “decision-making enhancement” and “new product/service development,” and finally the focal challenge threatening the efforts and expected outputs is “information silos and unintegrated data.” Originality/value In addition to stepping forward in the literature, the findings advance our understanding of the main managerial issues of big data in a dynamic business environment, by proposing effective further actions for both scholars and decision-makers
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