67 research outputs found
Pulmonary Hypertension Registry of Kerala (PROKERALA) â Rationale, design and methods
AbstractBackgroundPulmonary hypertension (PH) is a disease associated with a high morbidity and mortality. There is paucity of data regarding PH from the developing countries including India.Idiopathic pulmonary arterial hypertension is the most important etiological factor in the western world, but PH secondary to rheumatic heart disease, chronic obstructive pulmonary disease and untreated congenital heart disease could well be the predominant causes in developing countries like India.The main objective of the PROKERALA study â Pulmonary hypertension Registry Of Kerala is to collect data regarding the etiology, practice patterns and one-year outcomes of patients diagnosed to have PH.MethodsThe study is a hospital-based registry in the state of Kerala supported and funded by the Cardiological Society of India, Kerala Chapter. A total of 77 hospitals have agreed to participate in the registry. PH was defined as systolic pulmonary artery pressure derived by echocardiography of more than 50mmHg (by tricuspid regurgitation jet) or mean PA pressure more than 25mmHg obtained at cardiac catheterization.A detailed questionnaire is administered which includes the demographic characteristics, risk factors, family history, ECG data, 6 minute walk test distance, chest X ray findings and echocardiographic data. Details of PH specific therapy and one-year follow-up data are collected.From a preliminary survey in the region, we estimated that we will be able to collect 2000 cases over a period of one year
On the properties of Cu2ZnSn(S,Se)4 thin ïŹlms prepared by selenization of binary precursors using rapid thermal processing
Cu2ZnSn(S,Se)4 thin ïŹlms were grown on molybdenum coated glass substrates by selenization of stacked precursor layers of zinc, tin disulïŹde and copper sulïŹde. Selenization was performed using a rapid thermal processor at maximum temperatures in the range of 400°C to 550°C and at heating rates of 1°C/s and 2°C/s. The compositional, morphological and structural characterization of the ïŹlms was carried out using energy dispersive x-ray spectroscopy, scanning electron microscopy, x-ray diffraction and Raman spectroscopy. X-ray diffraction and Raman scattering analysis suggests the formation of Cu2ZnSn(S,Se)4 only at lower temperatures, whereas Cu2ZnSnSe4 was formed at higher temperatures regardless of the heating rate used. Compositional analysis revealed that the ïŹlms were Zn-poor and Sn-rich. However, the samples approach a near stoichiometric composition due to the loss of tin at a selenization temperature and heating rate of 550°C and 2°C/s, respectively. Large grains with an average lateral dimension of 4.5ÎŒm were observed for ïŹlms prepared at these conditions which are very desirable for an absorber for solar cells.info:eu-repo/semantics/publishedVersio
Effect of selenization conditions on the growth and properties of Cu2ZnSn(S,Se)4 thin films
Cu2ZnSn(S,Se)4 (CZTSSe) is a potentially cost effective candidate for future thin film solar cells (TFSCs). We report the growth of CZTSSe using a hybrid process involving the sequential evaporation of Zn and sputtering of the sulfide precursors of Cu and Sn, followed by a selenization step. Two approaches for selenization were followed, one using a tubular furnace (TF) and the other using a Rapid Thermal Processor (RTP). SEM and EDS were employed to investigate the morphology and composition of the films. Structural analyses were done using XRD and Raman spectroscopy. Structural analyses revealed the formation of CZTSSe. The effects of annealing conditions on the morphological and structural properties of the films were investigated.N/
Asymptotic Behavior of Inflated Lattice Polygons
We study the inflated phase of two dimensional lattice polygons with fixed
perimeter and variable area, associating a weight to a
polygon with area and bends. For convex and column-convex polygons, we
show that , where , and . The
constant is found to be the same for both types of polygons. We argue
that self-avoiding polygons should exhibit the same asymptotic behavior. For
self-avoiding polygons, our predictions are in good agreement with exact
enumeration data for J=0 and Monte Carlo simulations for . We also
study polygons where self-intersections are allowed, verifying numerically that
the asymptotic behavior described above continues to hold.Comment: 7 page
Asymptotic behaviour of convex and column-convex lattice polygons with fixed area and varying perimeter
We study the inflated phase of two dimensional lattice polygons, both convex
and column-convex, with fixed area A and variable perimeter, when a weight
\mu^t \exp[- Jb] is associated to a polygon with perimeter t and b bends. The
mean perimeter is calculated as a function of the fugacity \mu and the bending
rigidity J. In the limit \mu -> 0, the mean perimeter has the asymptotic
behaviour \avg{t}/4 \sqrt{A} \simeq 1 - K(J)/(\ln \mu)^2 + O (\mu/ \ln \mu) .
The constant K(J) is found to be the same for both types of polygons,
suggesting that self-avoiding polygons should also exhibit the same asymptotic
behaviour.Comment: 10 pages, 3 figure
Independent Origins of Cultivated Coconut (Cocos nucifera L.) in the Old World Tropics
As a portable source of food, water, fuel, and construction materials, the coconut (Cocos nucifera L.) played a fundamental role in human migrations and the development of civilization across the humid tropics. Here we investigated the coconut's domestication history and its population genetic structure as it relates to human dispersal patterns. A sample of 1,322 coconut accessions, representing the geographical and phenotypic diversity of the species, was examined using ten microsatellite loci. Bayesian analyses reveal two highly genetically differentiated subpopulations that correspond to the Pacific and Indo-Atlantic oceanic basins. This pattern suggests independent origins of coconut cultivation in these two world regions, with persistent population structure on a global scale despite long-term human cultivation and dispersal. Pacific coconuts show additional genetic substructure corresponding to phenotypic and geographical subgroups; moreover, the traits that are most clearly associated with selection under human cultivation (dwarf habit, self-pollination, and âniu vaiâ fruit morphology) arose only in the Pacific. Coconuts that show evidence of genetic admixture between the Pacific and Indo-Atlantic groups occur primarily in the southwestern Indian Ocean. This pattern is consistent with human introductions of Pacific coconuts along the ancient Austronesian trade route connecting Madagascar to Southeast Asia. Admixture in coastal east Africa may also reflect later historic Arab trading along the Indian Ocean coastline. We propose two geographical origins of coconut cultivation: island Southeast Asia and southern margins of the Indian subcontinent
Molluscicidal effect of Euphorbia umbellata (Pax) Bruyns latex on Biomphalaria glabrata, Schistosoma mansoni host snail
ABSTRACT Euphorbia umbellata (Pax) Bruyns is an easily cultivated shrub, with occurrence in the tropical regions of the American and African continents. Chemical studies have revealed that the latex of this plant is rich in terpene compounds, which are highly toxic to snails Biomphalaria glabrata (Basommatophora: Planorbidae). The aim of this study was to evaluate the chemical composition and molluscicidal activity of the latex produced by E. umbellata, as well as the safety of its application in aquatic environments. The concentration of latex that killed 90% of the exposed snails after 24 h exposure (LC90) was 3.69 mg/L. Toxicity bioassays using Danio rerio (zebrafish) revealed that these animals were less susceptible to latex than planorbids. However, it is important to perform other toxicity tests to ensure the feasibility of using latex to control populations of mollusks that contribute to schistosomiasis transmission. A phytochemical screening performed with the E. umbellata latex identified the triterpenoid and coumarin class. Further studies are warranted to isolate, identify, and test the active compounds of E. umbellata latex in B. glabrata
Global Retinoblastoma Presentation and Analysis by National Income Level.
Importance: Early diagnosis of retinoblastoma, the most common intraocular cancer, can save both a child's life and vision. However, anecdotal evidence suggests that many children across the world are diagnosed late. To our knowledge, the clinical presentation of retinoblastoma has never been assessed on a global scale. Objectives: To report the retinoblastoma stage at diagnosis in patients across the world during a single year, to investigate associations between clinical variables and national income level, and to investigate risk factors for advanced disease at diagnosis. Design, Setting, and Participants: A total of 278 retinoblastoma treatment centers were recruited from June 2017 through December 2018 to participate in a cross-sectional analysis of treatment-naive patients with retinoblastoma who were diagnosed in 2017. Main Outcomes and Measures: Age at presentation, proportion of familial history of retinoblastoma, and tumor stage and metastasis. Results: The cohort included 4351 new patients from 153 countries; the median age at diagnosis was 30.5 (interquartile range, 18.3-45.9) months, and 1976 patients (45.4%) were female. Most patients (nâ=â3685 [84.7%]) were from low- and middle-income countries (LMICs). Globally, the most common indication for referral was leukocoria (nâ=â2638 [62.8%]), followed by strabismus (nâ=â429 [10.2%]) and proptosis (nâ=â309 [7.4%]). Patients from high-income countries (HICs) were diagnosed at a median age of 14.1 months, with 656 of 666 (98.5%) patients having intraocular retinoblastoma and 2 (0.3%) having metastasis. Patients from low-income countries were diagnosed at a median age of 30.5 months, with 256 of 521 (49.1%) having extraocular retinoblastoma and 94 of 498 (18.9%) having metastasis. Lower national income level was associated with older presentation age, higher proportion of locally advanced disease and distant metastasis, and smaller proportion of familial history of retinoblastoma. Advanced disease at diagnosis was more common in LMICs even after adjusting for age (odds ratio for low-income countries vs upper-middle-income countries and HICs, 17.92 [95% CI, 12.94-24.80], and for lower-middle-income countries vs upper-middle-income countries and HICs, 5.74 [95% CI, 4.30-7.68]). Conclusions and Relevance: This study is estimated to have included more than half of all new retinoblastoma cases worldwide in 2017. Children from LMICs, where the main global retinoblastoma burden lies, presented at an older age with more advanced disease and demonstrated a smaller proportion of familial history of retinoblastoma, likely because many do not reach a childbearing age. Given that retinoblastoma is curable, these data are concerning and mandate intervention at national and international levels. Further studies are needed to investigate factors, other than age at presentation, that may be associated with advanced disease in LMICs
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