6,442 research outputs found

    Phase and frequency entrainment in locally coupled phase oscillators with repulsive interactions

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    Recent experiments in one and two-dimensional microfluidic arrays of droplets containing Belousov -Zhabotinsky reactants show a rich variety of spatial patterns [J. Phys. Chem. Lett. 1, 1241-1246 (2010)]. The dominant coupling between these droplets is inhibitory. Motivated by this experimental system, we study repulsively coupled Kuramoto oscillators with nearest neighbor interactions, on a linear chain as well as a ring in one dimension, and on a triangular lattice in two dimensions. In one dimension, we show using linear stability analysis as well as numerical study, that the stable phase patterns depend on the geometry of the lattice. We show that a transition to the ordered state does not exist in the thermodynamic limit. In two dimensions, we show that the geometry of the lattice constrains the phase difference between two neighbouring oscillators to 120 degrees. We report the existence of domains with either clockwise or anti-clockwise helicity, leading to defects in the lattice. We study the time dependence of these domains and show that at large coupling strengths, the domains freeze due to frequency synchronization. Signatures of the above phenomena can be seen in the spatial correlation functions.Comment: 9 pages, 12 figure

    Highly Enhanced Concentration and Stability of Reactive Ce^3+ on Doped CeO_2 Surface Revealed In Operando

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    Trivalent cerium ions in CeO_2 are the key active species in a wide range of catalytic and electro-catalytic reactions. We employed ambient pressure X-ray photoelectron spectroscopy and electrochemical impedance spectroscopy to quantify simultaneously the concentration of the reactive Ce^3+ species on the surface and in the bulk of Sm-doped CeO_2(100) in hundreds of millitorr of H2–H2O gas mixtures. Under relatively oxidizing conditions, when the bulk cerium is almost entirely in the 4+ oxidation state, the surface concentration of the reduced Ce^3+ species can be over 180 times the bulk concentration. Furthermore, in stark contrast to the bulk, the surface’s 3+ oxidation state is also highly stable, with concentration almost independent of temperature and oxygen partial pressure. Our thermodynamic measurements reveal that the difference between the bulk and surface partial molar entropies plays a key role in this stabilization. The high concentration and stability of reactive surface Ce^3+ over wide ranges of temperature and oxygen partial pressure may be responsible for the high activity of doped ceria in many pollution-control and energy-conversion reactions, under conditions at which Ce^3+ is not abundant in the bulk

    Altered STAT4 isoform expression in patients with inflammatory bowel disease.

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    BACKGROUND & AIMS: Crohn’s disease (CD) and ulcerative colitis (UC) are major forms of inflammatory bowel disease (IBD) and pathogenesis involves a complex interplay between genetic, environmental and immunological factors. We evaluated isoform expression of the IL-12-activated transcription factor STAT4 in children with CD and UC. METHODS: We performed a study where we collected biopsy samples from both newly diagnosed CD and UC patients. We further collected blood samples from newly diagnosed CD and UC patients as well as patients who had a flare-up after being in clinical remission, and examined the ratios of STAT4β/STAT4α mRNA. In addition to STAT4 isoforms we measured the expression of the cytokines TNFα, IFNγ, GM-CSF and IL-17 using PCR of biopsy samples and multiplex analysis of patient serum samples. RESULTS: Ratios of STAT4β/STAT4α were increased in specific GI tract segments in both CD and UC patients that correlate with location and severity of inflammation. In contrast, we did not observe changes in STAT4β/STAT4α ratios in biopsy specimens from eosinophilic esophagitis patients. We also observed increased STAT4β/STAT4α ratios in the peripheral blood mononuclear cells of UC and CD patients, compared to healthy controls. Ratios were normalized after patient treatment with steroids. CONCLUSIONS: Collectively, these data indicate that STAT4 isoforms could be an important non-invasive biomarker in the diagnosis and treatment of IBD, and that expression of these isoforms might provide further insight into the pathogenesis of IBD

    Modelling learning for a better safety culture within an organization using a virtual safety coach:Reducing the risk of postpartum depression via improved communication with parents

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    This paper describes an extension of a safety culture within hospital organizations providing more transparency and acknowledgement of all actors, and in particular the parents. It contributes a model architecture to support a hospital to develop such an extended safety culture. It is illustrated for prevention of postpartum depression. Postpartum depression is a commonly known consequence of childbirth for both mothers and fathers. In this research, we computationally analyze the risk factors and lack of support received by fathers. Therefore, we use shared mental models to model the effects of poor and additional communication by healthcare practitioners to mitigate the development of postpartum depression in both the mother and the father. Both individual mental models and shared mental models are considered in the design of the computational model. The paper illustrates the benefits of simple support in terms of communication during childbirth, which has lasting effects, even outside the hospital. For the impact of additional communication, a Virtual Safety Coach is designed that intervenes when necessary to provide support, i.e., when a health care practitioner doesn't. Moreover, organizational learning is also modelled to improve the mental models of both the Safety Coach and the Health Care Practitioner.Safety and Security Scienc

    PU.1 expression in T follicular helper cells limits CD40L-dependent germinal center B cell development.

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    PU.1 is an ETS family transcription factor important for the development of multiple hematopoietic cell lineages. Previous work demonstrated a critical role for PU.1 in promoting Th9 development, and in limiting Th2 cytokine production. Whether PU.1 has functions in other T helper lineages is not clear. In this report we examined the effects of ectopic expression of PU.1 in CD4+T cells and observed decreased expression of genes involved with the function of T follicular helper (Tfh) cells, including Il21 and Tnfsf5 (encoding CD40L). T cells from conditional mutant mice that lack expression of PU.1 in T cells (Sfpi1lck−/−) demonstrated increased production of CD40L and IL-21 in vitro. Following adjuvant-dependent or adjuvant-independent immunization, we observed that Sfpi1lck−/− mice had increased numbers of Tfh cells, increased germinal center B cells, and increased antibody production in vivo. This correlated with increased expression of IL-21 and CD40L in Tfh cells from Sfpi1lck−/− mice, compared to control mice. Finally, although blockade of IL-21 did not affect germinal center B cells in Sfpi1lck−/− mice, anti-CD40L treatment of immunized Sfpi1lck−/− mice decreased germinal center B cell numbers and antigen-specific immunoglobulin concentrations. Together, these data indicate an inhibitory role of PU.1 in the function of T follicular helper cells, germinal centers, and Tfh-dependent humoral immunity

    The ETS family transcription factors Etv5 and PU.1 function in parallel to promote Th9 cell development

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    The IL-9-secreting Th9 subset of CD4 T helper cells develop in response to an environment containing IL-4 and TGFβ, promoting allergic disease, autoimmunity, and resistance to pathogens. We previously identified a requirement for the ETS family transcription factor PU.1 in Th9 development. In this report we demonstrate that the ETS transcription factor ETV5 promotes IL-9 production in Th9 cells by binding and recruiting histone acetyltransferases to the Il9 locus at sites distinct from PU.1. In cells that are deficient in both PU.1 and ETV5 there is lower IL-9 production than in cells lacking either factor alone. In vivo loss of PU.1 and ETV5 in T cells results in distinct affects on allergic inflammation in the lung, suggesting that these factors function in parallel. Together, these data define a role for ETV5 in Th9 development and extend the paradigm of related transcription factors having complementary functions during differentiation

    Ambient assisted living framework for elderly care using Internet of medical things, smart sensors, and GRU deep learning techniques

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    Due to the increase in the global aging population and its associated age-related challenges, various cognitive, physical, and social problems can arise in older adults, such as reduced walking speed, mobility, falls, fatigue, difficulties in performing daily activities, memory-related and social isolation issues. In turn, there is a need for continuous supervision, intervention, assistance, and care for elderly people for active and healthy aging. This research proposes an ambient assisted living system with the Internet of Medical Things that leverages deep learning techniques to monitor and evaluate the elderly activities and vital signs for clinical decision support. The novelty of the proposed approach is that bidirectional Gated Recurrent Unit, and Gated Recurrent Unit deep learning techniques with mutual information-based feature selection technique is applied to select robust features to identify the target activities and abnormalities. Experiments were conducted on two datasets (the recorded Ambient Assisted Living data and MHealth benchmark data) with bidirectional Gated Recurrent Unit, and Gated Recurrent Unit deep learning techniques and compared with other state of art techniques. Different evaluation metrics were used to assess the performance, findings reveal that bidirectional Gated Recurrent Unit deep learning techniques outperform other state of art approaches with an accuracy of 98.14% for Ambient Assisted Living data, and 99.26% for MHealth data using the proposed approach

    STAT4 deficiency reduces the development of atherosclerosis in mice

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    Atherosclerosis is a chronic inflammatory process that leads to plaque formation in large and medium sized vessels. T helper 1 (Th1) cells constitute the majority of plaque infiltrating pro-atherogenic T cells and are induced via IFNγ-dependent activation of T-box (Tbet) and/or IL-12-dependent activation of signal transducer and activator of transcription 4 (STAT4). We thus aimed to define a role for STAT4 in atherosclerosis. STAT4-deficiency resulted in a ∼71% reduction (p < 0.001) in plaque burden in Stat4(-/-)Apoe(-/-) vs Apoe(-/-) mice fed chow diet and significantly attenuated atherosclerosis (∼31%, p < 0.01) in western diet fed Stat4(-/-)Apoe(-/-) mice. Surprisingly, reduced atherogenesis in Stat4(-/-)Apoe(-/-) mice was not due to attenuated IFNγ production in vivo by Th1 cells, suggesting an at least partially IFNγ-independent pro-atherogenic role of STAT4. STAT4 is expressed in T cells, but also detected in macrophages (MΦs). Stat4(-/-)Apoe(-/-)in vitro differentiated M1 or M2 MΦs had reduced cytokine production compare to Apoe(-/-) M1 and M2 MΦs that was accompanied by reduced induction of CD69, I-A(b), and CD86 in response to LPS stimulation. Stat4(-/-)Apoe(-/-) MΦs expressed attenuated levels of CCR2 and demonstrated reduced migration toward CCL2 in a transwell assay. Importantly, the percentage of aortic CD11b(+)F4/80(+)Ly6C(hi) MΦs was reduced in Stat4(-/-)Apoe(-/-) vs Apoe(-/-) mice. Thus, this study identifies for the first time a pro-atherogenic role of STAT4 that is at least partially independent of Th1 cell-derived IFNγ, and primarily involving the modulation of MΦ responses

    Child mortality in Bangladesh - why, when, where and how?:A national survey-based analysis

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    BACKGROUND: Updated information on the cause of childhood mortality is essential for developing policies and designing programmes targeting the major burden of disease. There is a paucity of evidence regarding the current estimates of the cause of death in Bangladesh, which is essential for reinvigorating the current policies and reshaping existing strategies to avert preventable deaths. This paper aims to address this critical evidence gap and report the cause, timing and place of death among children under-five years of age using a nationally representative sample. METHODS: The present study was undertaken to provide updated estimates of causes of death among children under-five years of age using data from the 2017-18 round of the Bangladesh Demographic and Health Survey (BDHS). The verbal autopsy (VA) questionnaire of the 2017-18 BDHS was adapted from the standardised WHO 2016 instruments. Specially trained physicians reviewed the responses of the VA questionnaire and assigned the cause of death based on the online-2016-version of the International Classification of Diseases (ICD-10). We included 456 deaths among children under-five years of age in our analysis. Descriptive statistics were used to present the causes, timing and places of death with uncertainty ranges (UR). RESULTS: Pneumonia is the major killer (19%), accounting for approximately 24 268 (UR = 21 626-26 695) under-five deaths per-year. It is followed by birth asphyxia (16%), prematurity and low-birth-weight (11%), serious infections including sepsis (8%) causing 20 882 (UR = 18 608-22 970), 14 956 (UR = 13 327-16,452), and 10 723 (UR = 9555-11,795) deaths per-year, respectively. Drowning (8%) caused 10 441 (UR = 9304-11 485) deaths and congenital anomaly (7%) resulted in d 8748 (UR = 7795-9623) deaths per-year. Around 29% of all deaths occurred on the first day, 52% within the first week, and 66% within the first month of life. Around 70% of birth asphyxia, prematurity, and low birth weight-related deaths happen on the day of birth. Approximately 43% of pneumonia-related deaths occur in age 1-11 months, and around 51% of drowning-related deaths happen in age 12-23 months. CONCLUSIONS: Pneumonia with other serious infections, birth asphyxia, prematurity and low-birth-weight are responsible for more than half of all deaths among children under-five years of age. Strengthening the existing maternal, neonatal and child health programmes may be helpful in averting the majority of these preventable deaths. A multisectoral approach is required for the prevention of childhood deaths, especially drowning-related fatalities. Special measures need to be taken to prevent and control emerging public health challenges like birth defects and congenital anomalies

    Developing drought-smart, ready-to-grow future crops

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    Breeding crop plants with increased yield potential and improved tolerance to stressful environments is critical for global food security. Drought stress (DS) adversely affects agricultural productivity worldwide and is expected to rise in the coming years. Therefore, it is vital to understand the physiological, biochemical, molecular, and ecological mechanisms associated with DS. This review examines recent advances in plant responses to DS to expand our understanding of DS-associated mechanisms. Suboptimal water sources adversely affect crop growth and yields through physical impairments, physiological disturbances, biochemical modifications, and molecular adjustments. To control the devastating effect of DS in crop plants, it is important to understand its consequences, mechanisms, and the agronomic and genetic basis of DS for sustainable production. In addition to plant responses, we highlight several mitigation options such as omics approaches, transgenics breeding, genome editing, and biochemical to mechanical methods (foliar treatments, seed priming, and conventional agronomic practices). Further, we have also presented the scope of conventional and speed breeding platforms in helping to develop the drought-smart future crops. In short, we recommend incorporating several approaches, such as multi-omics, genome editing, speed breeding, and traditional mechanical strategies, to develop drought-smart cultivars to achieve the ‘zero hunger’ goal
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