162 research outputs found

    Unsupervised labelling of sequential data for location identification in indoor environments

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    In this paper we present indoor positioning within unknown environments as an unsupervised labelling task on sequential data. We explore a probabilistic framework relying on wireless network radio signals and contextual information, which is increasingly available in large environments. Thus, we form an informative spatial classifier without resorting to a pre-determined map, and show the potential of the approach using both simulated and real data sets. Results demonstrate the ability of the procedure to segregate structures of radio signal observations and form clustered regions in association to areas of interest to the user; thus, we show it is possible to differentiate location between closely spaced zones of variable size and shape

    Calcium Dependent CAMTA1 in Adult Stem Cell Commitment to a Myocardial Lineage

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    The phenotype of somatic cells has recently been found to be reversible. Direct reprogramming of one cell type into another has been achieved with transduction and over expression of exogenous defined transcription factors emphasizing their role in specifying cell fate. To discover early and novel endogenous transcription factors that may have a role in adult-derived stem cell acquisition of a cardiomyocyte phenotype, mesenchymal stem cells from human and mouse bone marrow and rat liver were co-cultured with neonatal cardiomyocytes as an in vitro cardiogenic microenvironment. Cell-cell communications develop between the two cell types as early as 24 hrs in co-culture and are required for elaboration of a myocardial phenotype in the stem cells 8-16 days later. These intercellular communications are associated with novel Ca(2+) oscillations in the stem cells that are synchronous with the Ca(2+) transients in adjacent cardiomyocytes and are detected in the stem cells as early as 24-48 hrs in co-culture. Early and significant up-regulation of Ca(2+)-dependent effectors, CAMTA1 and RCAN1 ensues before a myocardial program is activated. CAMTA1 loss-of-function minimizes the activation of the cardiac gene program in the stem cells. While the expression of RCAN1 suggests involvement of the well-characterized calcineurin-NFAT pathway as a response to a Ca(2+) signal, the CAMTA1 up-regulated expression as a response to such a signal in the stem cells was unknown. Cell-cell communications between the stem cells and adjacent cardiomyocytes induce Ca(2+) signals that activate a myocardial gene program in the stem cells via a novel and early Ca(2+)-dependent intermediate, up-regulation of CAMTA1

    Management and Outcome of Cardiac and Endovascular Cystic Echinococcosis

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    Cardiac and vascular involvement are infrequent in classical cystic echinococcosis (CE), but when they occur they tend to present earlier and are associated with complications that may be life threatening. Cardiovascular CE usually requires complex surgery, so in low-income countries the outcome is frequently fatal. This case series describes the characteristics of cardiovascular CE in patients diagnosed and treated at a Tropical Medicine & Clinical Parasitology Center in Spain. A retrospective case series of 11 patients with cardiac and/or endovascular CE, followed-up over a period of 15 years (1995–2009) is reported. The main clinical manifestations included thoracic pain or dyspnea, although 2 patients were asymptomatic. The clinical picture and complications vary according to cyst location. Isolated cardiac CE may be cured after surgery, while endovascular extracardiac involvement is associated with severe chronic complications. CE should be included in the differential diagnosis of cardiovascular disease in patients from endemic areas. CE is a neglected disease and further studies are necessary in order to make more definite management recommendations for this rare and severe form of the disease. The authors propose a general approach based on cyst location: exclusively cardiac, endovascular or both

    Subnormal vitamin B12 concentrations and anaemia in older people: a systematic review

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    <p>Abstract</p> <p>Background</p> <p>Pernicious anaemia is undeniably associated with vitamin B12 deficiency, but the association between subnormal vitamin B12 concentrations and anaemia in older people is unclear. The aim of this systematic review was to evaluate the association between subnormal vitamin B12 concentrations and anaemia in older people.</p> <p>Methods</p> <p>Clinical queries for aetiology and treatment in bibliographic databases (PubMed [01/1949-10/2009]; EMBASE [01/1980-10/2009]) were used. Reference lists were checked for additional relevant studies. Observational studies (≄50 participants) and randomized placebo-controlled intervention trials (RCTs) were considered.</p> <p>Results</p> <p>25 studies met the inclusion criteria. Twenty-one observational cross-sectional studies (total number of participants n = 16185) showed inconsistent results. In one longitudinal observational study, low vitamin B12 concentrations were not associated with an increased risk of anaemia (total n = 423). The 3 RCTs (total n = 210) were well-designed and showed no effect of vitamin B12 supplementation on haemoglobin concentrations during follow-up in subjects with subnormal vitamin B12 concentrations at the start of the study. Due to large clinical and methodological heterogeneity, statistical pooling of data was not performed.</p> <p>Conclusions</p> <p>Evidence of a positive association between a subnormal serum vitamin B12 concentration and anaemia in older people is limited and inconclusive. Further well-designed studies are needed to determine whether subnormal vitamin B12 is a risk factor for anaemia in older people.</p

    A Bird\u27s-Eye View of the Multiple Biochemical Mechanisms that Propel Pathology of Alzheimer\u27s Disease: Recent Advances and Mechanistic Perspectives on How to Halt the Disease Progression Targeting Multiple Pathways.

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    Neurons consume the highest amount of oxygen, depend on oxidative metabolism for energy, and survive for the lifetime of an individual. Therefore, neurons are vulnerable to death caused by oxidative-stress, accumulation of damaged and dysfunctional proteins and organelles. There is an exponential increase in the number of patients diagnosed with neurodegenerative diseases such as Alzheimer’s (AD) as the number of elderly increases exponentially. Development of AD pathology is a complex phenomenon characterized by neuronal death, accumulation of extracellular amyloid-ÎČ plaques and neurofibrillary tangles, and most importantly loss of memory and cognition. These pathologies are most likely caused by mechanisms including oxidative stress, mitochondrial dysfunction/stress, accumulation of misfolded proteins, and defective organelles due to impaired proteasome and autophagy mechanisms. Currently, there are no effective treatments to halt the progression of this disease. In order to treat this complex disease with multiple biochemical pathways involved, a complex treatment regimen targeting different mechanisms should be investigated. Furthermore, as AD is a progressive disease-causing morbidity over many years, any chemo-modulator for treatment must be used over long period of time. Therefore, treatments must be safe and non-interfering with other processes. Ideally, a treatment like medicinal food or a supplement that can be taken regularly without any side effect capable of reducing oxidative stress, stabilizing mitochondria, activating autophagy or proteasome, and increasing energy levels of neurons would be the best solution. This review summarizes progress in research on different mechanisms of AD development and some of the potential therapeutic development strategies targeting the aforementioned pathologies

    ICAR: endoscopic skull‐base surgery

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