393 research outputs found

    Erbium doped LaF3 nanoparticles incorporated in silicondioxide thin films for active integrated optical applications

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    We report on the low-cost processing of erbium doped lanthanum trifluoride (LaF3:Er) nanoparticles dispersed in silicondioxide (SiO2) films prepared through the sol-gel method. The influence of particle concentration and annealing temperature on the optical properties and its implications on scattering in the visible wavelength range will be discussed. Uniform, crackfree and low loss films have been obtained by spincoating multiple layers followed by several annealing steps. The lanthanum trifluoride host shields the erbium from the OH-groups present in the silicondioxide, resulting in a higher excited state lifetime of the erbium due to the reduced OH-quenching

    Correlation of Levels of hs-CRP and Plasma Fibrinogen with increasing Severity of COPD

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    INTRODUCTION: Systemic inflammation is increasingly being recognized as a risk factor for a number of different complications including atherosclerosis1 cachexia, anorexia, and osteoporosis. Notably, all of these complications are commonly observed in patients with chronic obstructive pulmonary disease (COPD). Chronic obstructive pulmonary disease (COPD) is characterized by airway inflammation which is considered to play a pathogenic role in this disorder. An increase in both bronchial and systemic inflammation has also been demonstrated. Whether systemic inflammation is present in stable COPD and whether it is wholly or partially responsible for these associations is controversial. Although several studies have been undertaken to evaluate this potential relationship, most of the studies have been conducted during exacerbations of copd and among western population. We wanted to study the correlation of levels of hs-crp and plasma fibrinogen with increasing severity of COPD among Indian patients presenting to OPD in GGH, MMC, CHENNAI. We choose these markers of systemic inflammation because they have been well studied and have been intimately linked with the development of ischaemic heart disease and stroke which, interestingly, are also the leading causes of mortality among patients with COPD. There is evidence to suggest an imbalance in systemic levels of pro- and anti-inflammatory mediators in patients with stable COPD. The presence of these proinflammatory markers in increased levels in patients with COPD in both stable state and during exacerrebration might predispose them to adverse cardiovascular, cerebrovascular events acutely and the presence of a chronic inflammatory state may predispose to systemic effects such as cachexia, decreased bone mineral density with attendant risk of fracture, renal dysfunction, accelerated atherosclerosis, malignancy and anaemia. The treatment of this chronic inflammatory state and the early treatment of acute exacerrebration with conventional and possible newer therapeutic targets could possibly lead to lower incidence of these systemic effects and organ damage in this population. Also the role of prophylactic against these systemic and specific organ damage may be valuable intervention. This observative study was done to see if there was significant rise in the levels of these pro inflammatory marker, i.e., hs-CRP and plasma fibrinogen (Possibly stimulated by IL-6) as well as other markers such as ESR, polymorph percentage of total WBC count, pack years with increasing levels of severity as it could possibly lead to consensus on treatment protocols based on these levels during acute or chronic COPD. AIMS AND OBJECTIVES: The principal aims of this study were to: 1. To determine the correlation of hs-CRP and plasma fibrinogen levels with increasing severity of COPD in 80 patients presenting our hospital in GGH, Chennai. 2. To study the prevalence of the levels of various systemic markers of inflammation i.e., ESR, hs-CRP, plasma fibrinogen, polymorph percent of total WBC count in these patients with COPD at different stages as per GOLD criteria and FEV1 percentage of predicted value. 3. To study and observe the relationship between the distribution of these variables in this group and correlation with age, BMI, pack years of smoking. METHODS AND MATERIALS: A total of 80 patients of COPD coming to GGH, MMC were be screened for COPD by history clinical examination and PFT. Patients with features consistent with copd and FEV1/ FVC ratio less than 0.7 were be chosen for the study. The FEV1/FVCratio, reflecting the rate of emptying of the lung, is used to define the presence of an obstructive ventilatory defect. They were be categorized according to GOLD criteria using the percentage of predicted FEV1 for severity of COPD. Their blood levels of hs-CRP and plasma fibrinogen were be measured. The electronic super Spiro machine was used for doing pulmonary function tests after giving appropriate instructions and ensuring the patient is not having any respiratory infection and repeated twice to measure the best possible effort by the patient. The hs-CRP was measured by nephalometric method using the turbox analyzer. Plasma fibrinogen was measured using immuno turbidimetric method Olympus AU400 analyzer. Other parameters such as BMI, ESR, polymorph percentage, pack years of smoking were recorded of individuals. A careful history with regard to the patients symptoms of COPD, smoking habits, cardiovascular illness, renal or liver disorders, any connective tissue, autoimmune, vascullitic disorders, diabetes, hypertension, peripheral vascular disease was obtained. A thorough head to foot clinical examination of all the systems were done. A routine battery of investigations to test for renal, liver function, diabetes, presence of ischaemic heart disease, or tuberculosis was done to carefully select patients as per exclusion criteria. Research Design: This is a cross-sectional study assessing the levels of plasma fibrinogen, hs-CRP among other parameters such as ESR, polymorph percent, BMI, pack years of smoking, FEV1 percent of predicted in patients with COPD involving 80 participants presenting to MMC, Government General Hospital, Chennai. Study setting: This study was done in the institute of internal medicine in Government General Hospital, Madras Medical College, Chennai with inputs and active cooperation from the department of thoracic medicine. Government General Hospital, MMC, Chennai. Methodology: This is a cross-sectional study conducted as described above on patients in the age group 20-60 years. Patients, after informed consent were recruited into study, if they were eligible as per the criteria below. Inclusion criteria: Patients attending OPD and admitted to Medical Department in the Government General Hospital with clinical features of COPD, i.e.; cough with expectoration, dyspnea, wheeze and FEV1/FVC ratio of less than 0.7 showing obstructive features on electronic Spirometry and without any comorbid illness are selected for the study. Exclusion criteria: 1. Patients who are terminally ill, critically or acutely, 2. Age 60 yrs, 3. Diabetics, hypertensive, past history of M.I, Stroke, TIA, 4. Any arterial or venous thrombosis, peripheral vascular disease, 5. H/o of immunological disorders like rheumatoid arthritis, SLE, ankylosing spondillitis. 6. H/o cancer, renal disease, liver disorder, 7. Ongoing infections. OBSERVATION AND RESULTS: THE study was done on 80 patients presenting to the medical department and were selected randomly as per the inclusion criteria and exclusion criteria. All individual patients were informed of the study and their consent was obtained. Pulmonary function tests were done in these patient after excluding the conditions listed in the exclusion criteria with careful clinical history and simple tests such as RFT, LFT, complete blood counts, ECG,CXR, ECHO, etc. PFT was done in the department of thoracic medicine using the electronic super Spiro machine and the patients individual FEV1, FVC, FEVI percentage of predicted value, FEV1/FVC was calculated and they were staged according to GOLD stage of COPD. STAGE 4 diseases was excluded. STASTISTICAL ANALYSIS: Data analysis was done with use of SPSS, version 10. Descriptive statistics were used to calculate the frequency, mean, and standard deviation. To examine the linear trend of the proportions, trend chi-square was used and to find the test of association chi-square was computed. The correlation of variables i.e., age ,BMI, ESR, polymorph percent of total count, hs- CRP, plasma fibrinogen with severity of COPD as per GOLD stage was analyzed with chi-square test using the Pearson method. The correlation between pack years with GOLD stage was analyzed using the anova test followed by the tukey- hsd test. The correlation between the variables i.e., age ,BMI, ESR, polymorph percent of total count, hs- CRP, plasma fibrinogen with FEV1 percentage of predicted values was analyzed using correlation coefficients. The correlation between the variables i.e., age ,BMI, ESR, polymorph percent of total count, hs- CRP, plasma fibrinogen and FEV1 percentage of predicted values with pack years of smoking was analyzed using correlation coefficients. CONCLUSIONS: 1. hs-CRP has been found to be significantly elevated with increasing severity of COPD which could lead to increased predisposition to cardio vascular morbidity and mortality. 2. Plasma Fibrinogen levels were not found to be significant marker of COPD coagulopathy in our study or stable COPD. More studies are needed. 3. Polymorph percentages, ESR are not significant markers of inflammation in COPD. 4. ESR, hs-CRP, Plasma Fibrinogen are markers of increasing exposure to smoking. 5. Physicians need to approach COPD as a multi system disease and identify patients with the associated co-morbidities of COPD vis-à-vis the extra pulmonary manifestations of COPD

    Operational framework based on modeling languages to support product repository implementation.

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    Part 3: Tools and MethodologiesInternational audienceEmbracing Product Lifecycle Management approach involves integrating a product repository in the company information system. From customer's needs to disposal stage, several product representations exist. The product repository purpose is to secure consistency of one product representation with the others. This paper presents an operational modeling framework that supports product repository implementation. In order to ensure consistency, this framework identifies correspondences between entities of languages (“trade” languages and standard languages). The presented concepts are illustrated with correspondences between language entities of product designed and productplanned to be built Bills of Materials

    Методы измерения фазового сдвига с промежуточным преобразованием напряжение-частота

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    В статті розглянуті методи вимірювання фазового зсуву з проміжним перетворенням напруга-частота. Проаналізовано переваги й недоліки методів. Проведено оцінку похибки, обумовленої неточністю формування часових інтервалів.In article methods of measurement of phase shift with preliminary transformation a voltage-frequency are considered. Their merits and demerits are analyzed. The estimation of the error caused by discrepancy of formation of time intervals is made

    Detection of a Westward Hotspot Offset in the Atmosphere of a Hot Gas Giant CoRoT-2b

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    Short-period planets exhibit day-night temperature contrasts of hundreds to thousands of degrees K. They also exhibit eastward hotspot offsets whereby the hottest region on the planet is east of the substellar point; this has been widely interpreted as advection of heat due to eastward winds. We present thermal phase observations of the hot Jupiter CoRoT-2b obtained with the IRAC instrument on the Spitzer Space Telescope. These measurements show the most robust detection to date of a westward hotspot offset of 23 ±\pm 4 degrees, in contrast with the nine other planets with equivalent measurements. The peculiar infrared flux map of CoRoT-2b may result from westward winds due to non-synchronous rotation magnetic effects, or partial cloud coverage, that obscures the emergent flux from the planet's eastern hemisphere. Non-synchronous rotation and magnetic effects may also explain the planet's anomalously large radius. On the other hand, partial cloud coverage could explain the featureless dayside emission spectrum of the planet. If CoRoT-2b is not tidally locked, then it means that our understanding of star-planet tidal interaction is incomplete. If the westward offset is due to magnetic effects, our result represents an opportunity to study an exoplanet's magnetic field. If it has Eastern clouds, then it means that our understanding of large-scale circulation on tidally locked planets is incomplete.Comment: 30 pages, 4 figures, 15 supplementary figure

    Ligand recognition determinants of guanine riboswitches

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    Guanine riboswitches negatively modulate transcription upon guanine binding. The aptamer domain is organized around a three-way junction which forms the ligand binding site. Using currently available 89 guanine aptamer sequences, a consensus secondary structure is deduced and reveals differences from the previously identified aptamer consensus. Three positions are found to display different nucleotide requirements. Using a 2-aminopurine binding assay, we show that variations are allowed depending on the aptamer context. However, changes at position 48 markedly decrease ligand binding in a context-independent fashion. This is consistent with previous observations with the adenine riboswitch in which position 48 was proposed to interact with position 74, which normally base pairs with the ligand. The in vivo transcriptional control of endogenous Bacillus subtilis guanine riboswitches was studied using RT-qPCR assays. The ratio of elongated/terminated transcripts is decreased in presence of a high concentration of guanine but is dependent on the riboswitch analyzed. In general, the aptamer-2AP complex affinity correlates well with the in vivo regulation efficiency of the corresponding riboswitch. These studies suggest that core variations of guanine aptamers are used to produce a spectrum of ligand binding affinities which is used in vivo by host riboswitches to perform gene regulation

    Understanding the errors of SHAPE-directed RNA structure modeling

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    Single-nucleotide-resolution chemical mapping for structured RNA is being rapidly advanced by new chemistries, faster readouts, and coupling to computational algorithms. Recent tests have shown that selective 2'-hydroxyl acylation by primer extension (SHAPE) can give near-zero error rates (0-2%) in modeling the helices of RNA secondary structure. Here, we benchmark the method using six molecules for which crystallographic data are available: tRNA(phe) and 5S rRNA from Escherichia coli, the P4-P6 domain of the Tetrahymena group I ribozyme, and ligand-bound domains from riboswitches for adenine, cyclic di-GMP, and glycine. SHAPE-directed modeling of these highly structured RNAs gave an overall false negative rate (FNR) of 17% and a false discovery rate (FDR) of 21%, with at least one helix prediction error in five of the six cases. Extensive variations of data processing, normalization, and modeling parameters did not significantly mitigate modeling errors. Only one varation, filtering out data collected with deoxyinosine triphosphate during primer extension, gave a modest improvement (FNR = 12%, and FDR = 14%). The residual structure modeling errors are explained by the insufficient information content of these RNAs' SHAPE data, as evaluated by a nonparametric bootstrapping analysis. Beyond these benchmark cases, bootstrapping suggests a low level of confidence (<50%) in the majority of helices in a previously proposed SHAPE-directed model for the HIV-1 RNA genome. Thus, SHAPE-directed RNA modeling is not always unambiguous, and helix-by-helix confidence estimates, as described herein, may be critical for interpreting results from this powerful methodology.Comment: Biochemistry, Article ASAP (Aug. 15, 2011

    Functional architecture and specifications for Tolerancing Data and Knowledge Management

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    Part 1: Knowledge ManagementInternational audienceThe paper deals with the Computer-Aided Tolerancing and Product Data Management. It is especially focus on data and knowledge management system to support and improve the tolerancing tasks in product development process. The first part of the paper introduces an overview about the recent developments related to tolerancing supports and data management systems. Based on a literature survey and industrial issues, the second part proposes a functional architecture and specifications of the data and knowledge manage-ment system addressing the numerous needs clarified by tolerancing experts

    Are diamonds a MEMS\u27 best friend?

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    Next-generation military and civilian communication systems will require technologies capable of handling data/ audio, and video simultaneously while supporting multiple RF systems operating in several different frequency bands from the MHz to the GHz range [1]. RF microelectromechanical/nanoelectromechanical (MEMS/NEMS) devices, such as resonators and switches, are attractive to industry as they offer a means by which performance can be greatly improved for wireless applications while at the same time potentially reducing overall size and weight as well as manufacturing costs
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