2,555 research outputs found

    Topologies of wireless mesh networks with inband backhauling

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    Proceedings of: PIMRC 2010: 21st Annual IEEE International Symposium on Personal, Indoor and Mobile Radio Communications took place from 26-30 Sep. 2010 in Istanbul, TurkeyWireless mesh networks (WMNs) with in band backhauling use the same antennas for the backhaul as well as for the access. Therefore antennas of next hop neighbours need to be directed to each other. However, such a configuration is not possible in a three-sectorized hexagonal cell deployment. In this paper we derive several alternative topologies that are suitable for WMNs with in band backhauling. We show that a topology with four directional antennas per node and backhaul connectivity between indirect neighbours outperforms competing topologies in terms of handover rate, optimal maximum power, and system capacity.European Community's Seventh Framework ProgramPublicad

    Clinical risk factors for age-related macular degeneration: a systematic review and meta-analysis

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    BACKGROUND: Age-related macular degeneration (AMD) is the leading cause of blindness in Western countries. Numerous risk factors have been reported but the evidence and strength of association is variable. We aimed to identify those risk factors with strong levels of evidence which could be easily assessed by physicians or ophthalmologists to implement preventive interventions or address current behaviours. METHODS: A systematic review identified 18 prospective and cross-sectional studies and 6 case control studies involving 113,780 persons with 17,236 cases of late AMD that included an estimate of the association between late AMD and at least one of 16 pre-selected risk factors. Fixed-effects meta-analyses were conducted for each factor to combine odds ratio (OR) and/or relative risk (RR) outcomes across studies by study design. Overall raw point estimates of each risk factor and associated 95% confidence intervals (CI) were calculated. RESULTS: Increasing age, current cigarette smoking, previous cataract surgery, and a family history of AMD showed strong and consistent associations with late AMD. Risk factors with moderate and consistent associations were higher body mass index, history of cardiovascular disease, hypertension, and higher plasma fibrinogen. Risk factors with weaker and inconsistent associations were gender, ethnicity, diabetes, iris colour, history of cerebrovascular disease, and serum total and HDL cholesterol and triglyceride levels. CONCLUSIONS: Smoking, previous cataract surgery and a family history of AMD are consistent risk factors for AMD. Cardiovascular risk factors are also associated with AMD. Knowledge of these risk factors that may be easily assessed by physicians and general ophthalmologists may assist in identification and appropriate referral of persons at risk of AMD

    Quantitative Mass Spectrometry Evaluation of Human Retinol Binding Protein 4 and Related Variants

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    Background: Retinol Binding Protein 4 (RBP4) is an exciting new biomarker for the determination of insulin resistance and type 2 diabetes. It is known that circulating RBP4 resides in multiple variants which may provide enhanced clinical utility, but conventional immunoassay methods are blind to such differences. A Mass Spectrometric immunoassay (MSIA) technology that can quantitate total RBP4 as well as individual isoforms may provide an enhanced analysis for this biomarker. Methods: RBP4 was isolated and detected from 0.5 uL of human plasma using MSIA technology, for the simultaneous quantification and differentiation of endogenous human RBP4 and its variants. Results: The linear range of the assay was 7.81–500 ug/mL, and the limit of detection and limit of quantification were 3.36 ug/mL and 6.52 ug/mL, respectively. The intra-assay CVs were determined to be 5.1 % and the inter-assay CVs were 9.6%. The percent recovery of the RBP4-MSIA ranged from 95 – 105%. Method comparison of the RBP4 MSIA vs the Immun Diagnostik ELISA yielded a Passing & Bablok fit of MSIA = 1.056 ELISA – 3.09, while the Cusum linearity p-value was.0.1 and the mean bias determined by the Altman Bland test was 1.2%. Conclusion: The novel RBP4 MSIA provided a fast, accurate and precise quantitative protein measurement as compared to the standard commercially available ELISA. Moreover, this method also allowed for the detection of RBP4 variants that are present in each sample, which may in the future provide a new dimension in the clinical utility of this biomarker

    A case of McKusick-Kaufman syndrome

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    McKusick-Kaufman syndrome (MKS) is an autosomal recessive multiple malformation syndrome characterized by hydrometrocolpos (HMC) and postaxial polydactyly (PAP). We report a case of a female child with MKS who was transferred to the neonatal intensive care unit of Seoul National University Children's Hospital on her 15th day of life for further evaluation and management of an abdominal cystic mass. She underwent abdominal sonography, magnetic resonance imaging, genitography and cystoscopy which confirmed HMC with a transverse vaginal septum. X-rays of the hand and foot showed bony fusion of the left third and fourth metacarpal bones, right fourth dysplastic metacarpal bone and phalanx, right PAP and hypoplastic left foot with left fourth and fifth dysplastic metatarsal bones. In addition, she had soft palate cleft, mild hydronephroses of both kidneys, hypoplastic right kidney with ectopic location and mild rotation, uterine didelphys with transverse vaginal septum and low-type imperforated anus. She was temporarily treated with ultrasound-guided transurethral aspiration of the HMC. Our patient with HMC and PAP was diagnosed with MKS because she has two typical abnormality of MKS and she has no definite complications of retinal disease, learning disability, obesity and renal failure that develop in Bardet-Biedl syndrome, but not in MKS until 33 months of age. Here, we describe a case of a Korean patient with MKS

    SPECULOOS exoplanet search and its prototype on TRAPPIST

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    One of the most significant goals of modern science is establishing whether life exists around other suns. The most direct path towards its achievement is the detection and atmospheric characterization of terrestrial exoplanets with potentially habitable surface conditions. The nearest ultracool dwarfs (UCDs), i.e. very-low-mass stars and brown dwarfs with effective temperatures lower than 2700 K, represent a unique opportunity to reach this goal within the next decade. The potential of the transit method for detecting potentially habitable Earth-sized planets around these objects is drastically increased compared to Earth-Sun analogs. Furthermore, only a terrestrial planet transiting a nearby UCD would be amenable for a thorough atmospheric characterization, including the search for possible biosignatures, with near-future facilities such as the James Webb Space Telescope. In this chapter, we first describe the physical properties of UCDs as well as the unique potential they offer for the detection of potentially habitable Earth-sized planets suitable for atmospheric characterization. Then, we present the SPECULOOS ground-based transit survey, that will search for Earth-sized planets transiting the nearest UCDs, as well as its prototype survey on the TRAPPIST telescopes. We conclude by discussing the prospects offered by the recent detection by this prototype survey of a system of seven temperate Earth-sized planets transiting a nearby UCD, TRAPPIST-1.Comment: Submitted as a chapter in the "Handbook of Exoplanets" (editors: H. Deeg & J.A. Belmonte; Section Editor: N. Narita). 16 pages, 4 figure

    Moving toward a system genetics view of disease

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    Testing hundreds of thousands of DNA markers in human, mouse, and other species for association to complex traits like disease is now a reality. However, information on how variations in DNA impact complex physiologic processes flows through transcriptional and other molecular networks. In other words, DNA variations impact complex diseases through the perturbations they cause to transcriptional and other biological networks, and these molecular phenotypes are intermediate to clinically defined disease. Because it is also now possible to monitor transcript levels in a comprehensive fashion, integrating DNA variation, transcription, and phenotypic data has the potential to enhance identification of the associations between DNA variation and diseases like obesity and diabetes, as well as characterize those parts of the molecular networks that drive these diseases. Toward that end, we review methods for integrating expression quantitative trait loci (eQTLs), gene expression, and clinical data to infer causal relationships among gene expression traits and between expression and clinical traits. We further describe methods to integrate these data in a more comprehensive manner by constructing coexpression gene networks that leverage pairwise gene interaction data to represent more general relationships. To infer gene networks that capture causal information, we describe a Bayesian algorithm that further integrates eQTLs, expression, and clinical phenotype data to reconstruct whole-gene networks capable of representing causal relationships among genes and traits in the network. These emerging network approaches, aimed at processing high-dimensional biological data by integrating data from multiple sources, represent some of the first steps in statistical genetics to identify multiple genetic perturbations that alter the states of molecular networks and that in turn push systems into disease states. Evolving statistical procedures that operate on networks will be critical to extracting information related to complex phenotypes like disease, as research goes beyond a single-gene focus. The early successes achieved with the methods described herein suggest that these more integrative genomics approaches to dissecting disease traits will significantly enhance the identification of key drivers of disease beyond what could be achieved by genetic association studies alone

    Scintigraphic evaluation of oesophageal transit during radiotherapy to the mediastinum

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    Background: To quantitatively evaluate radiation-induced impaired oesophageal transit with oesophageal transit scintigraphy and to assess the relationships between acute oesophagitis symptoms and dysmotility.\ud \ud Methods: Between January 1996 and November 1998, 11 patients affected by non-small-cell carcinoma of the lung not directly involving the oesophagus, requiring adjuvant external beam radiotherapy (RT) to the mediastinum were enrolled. Oesophageal transit scans with liquid and semisolid bolus were performed at three pre-defined times: before (T0) and during radiation at 10 Gy (T1) and 30 Gy (T2). Two parameters were obtained for evaluation: 1) mean transit time (MTT); and 2) ratio between peak activity and residual activity at 40 seconds (ER-40s). Acute radiation toxicity was scored according to the joint EORTC-RTOG criteria. Mean values with standard deviation were calculated for all parameters. Analysis of variance (ANOVA) tests and paired t-Tests for all values were performed.\ud \ud Results: An increase in the ER-40s from T0 to T1 or T2 was seen in 9 of 11 patients (82%). The mean ER-40s value for all patients increased from 0.8306 (T0) to 0.8612 (T1) and 0.8658 (T2). These differences were statistically significant (p < 0.05) in two paired t-Tests at T0 versus T2 time: overall mean ER-40s and upright ER-40s (p = 0.041 and p = 0.032, respectively). Seven patients (63%) showed a slight increase in the mean MTT value during irradiation but no statistically significant differences in MTT parameters were found between T0, T1 and T2 (p > 0.05).\ud \ud Conclusion: Using oesophageal scintigraphy we were able to detect early alterations of oesophageal transit during the third week of thoracic RT

    Expression and trans-specific polymorphism of self-incompatibility RNases in Coffea (Rubiaceae)

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    Self-incompatibility (SI) is widespread in the angiosperms, but identifying the biochemical components of SI mechanisms has proven to be difficult in most lineages. Coffea (coffee; Rubiaceae) is a genus of old-world tropical understory trees in which the vast majority of diploid species utilize a mechanism of gametophytic self-incompatibility (GSI). The S-RNase GSI system was one of the first SI mechanisms to be biochemically characterized, and likely represents the ancestral Eudicot condition as evidenced by its functional characterization in both asterid (Solanaceae, Plantaginaceae) and rosid (Rosaceae) lineages. The S-RNase GSI mechanism employs the activity of class III RNase T2 proteins to terminate the growth of "self" pollen tubes. Here, we investigate the mechanism of Coffea GSI and specifically examine the potential for homology to S-RNase GSI by sequencing class III RNase T2 genes in populations of 14 African and Madagascan Coffea species and the closely related self-compatible species Psilanthus ebracteolatus. Phylogenetic analyses of these sequences aligned to a diverse sample of plant RNase T2 genes show that the Coffea genome contains at least three class III RNase T2 genes. Patterns of tissue-specific gene expression identify one of these RNase T2 genes as the putative Coffea S-RNase gene. We show that populations of SI Coffea are remarkably polymorphic for putative S-RNase alleles, and exhibit a persistent pattern of trans-specific polymorphism characteristic of all S-RNase genes previously isolated from GSI Eudicot lineages. We thus conclude that Coffea GSI is most likely homologous to the classic Eudicot S-RNase system, which was retained since the divergence of the Rubiaceae lineage from an ancient SI Eudicot ancestor, nearly 90 million years ago.United States National Science Foundation [0849186]; Society of Systematic Biologists; American Society of Plant Taxonomists; Duke University Graduate Schoolinfo:eu-repo/semantics/publishedVersio

    Accreditation Standard Guideline Initiative for Tai Chi and Qigong Instructors and Training Institutions.

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    Evidence of the health and wellbeing benefits of Tai Chi and Qigong (TQ) have emerged in the past two decades, but TQ is underutilized in modern health care in Western countries due to lack of promotion and the availability of professionally qualified TQ instructors. To date, there are no government regulations for TQ instructors or for training institutions in China and Western countries, even though TQ is considered to be a part of Traditional Chinese medicine that has the potential to manage many chronic diseases. Based on an integrative health care approach, the accreditation standard guideline initiative for TQ instructors and training institutions was developed in collaboration with health professionals, integrative medicine academics, Tai Chi and Qigong master instructors and consumers including public safety officers from several countries, such as Australia, Canada, China, Germany, Italy, Korea, Sweden and USA. In this paper, the rationale for organizing the Medical Tai Chi and Qigong Association (MTQA) is discussed and the accreditation standard guideline for TQ instructors and training institutions developed by the committee members of MTQA is presented. The MTQA acknowledges that the proposed guidelines are broad, so that the diversity of TQ instructors and training institutions can be integrated with recognition that these guidelines can be developed with further refinement. Additionally, these guidelines face challenges in understanding the complexity of TQ associated with different principles, philosophies and schools of thought. Nonetheless, these guidelines represent a necessary first step as primary resource to serve and guide health care professionals and consumers, as well as the TQ community

    Modelling the cascade of biomarker changes in GRN-related frontotemporal dementia

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    OBJECTIVE: Progranulin-related frontotemporal dementia (FTD-GRN) is a fast progressive disease. Modelling the cascade of multimodal biomarker changes aids in understanding the aetiology of this disease and enables monitoring of individual mutation carriers. In this cross-sectional study, we estimated the temporal cascade of biomarker changes for FTD-GRN, in a data-driven way. METHODS: We included 56 presymptomatic and 35 symptomatic GRN mutation carriers, and 35 healthy non-carriers. Selected biomarkers were neurofilament light chain (NfL), grey matter volume, white matter microstructure and cognitive domains. We used discriminative event-based modelling to infer the cascade of biomarker changes in FTD-GRN and estimated individual disease severity through cross-validation. We derived the biomarker cascades in non-fluent variant primary progressive aphasia (nfvPPA) and behavioural variant FTD (bvFTD) to understand the differences between these phenotypes. RESULTS: Language functioning and NfL were the earliest abnormal biomarkers in FTD-GRN. White matter tracts were affected before grey matter volume, and the left hemisphere degenerated before the right. Based on individual disease severities, presymptomatic carriers could be delineated from symptomatic carriers with a sensitivity of 100% and specificity of 96.1%. The estimated disease severity strongly correlated with functional severity in nfvPPA, but not in bvFTD. In addition, the biomarker cascade in bvFTD showed more uncertainty than nfvPPA. CONCLUSION: Degeneration of axons and language deficits are indicated to be the earliest biomarkers in FTD-GRN, with bvFTD being more heterogeneous in disease progression than nfvPPA. Our data-driven model could help identify presymptomatic GRN mutation carriers at risk of conversion to the clinical stage
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