605 research outputs found
Effects of sand-shale anisotropy on amplitude variation with angle (AVA) modelling: The Sawan Gas Field (Pakistan) as a key case-study for South Asia's sedimentary basins
Amplitude variation with angle (AVA) is a technique widely used in the characterisation of hydrocarbon reservoirs and assumes the Earth’s crust to be an isotropic medium. Yet, anisotropy is ubiquitous in stratigraphic sequences and has first-order effects on seismic AVA responses when investigating subsurface prospects. This work analyses the effects of anisotropic strata on AVA responses using the Lower Goru Formation, middle Indus basin (Pakistan) as a case study. In the study area, shale intervals are interbedded with reservoir sands of the Sawan gas field. Shales in this field form laminae or are dispersed within reservoir sands, making the Lower Goru Formation an example of a vertically transversely isotropic (VTI) medium. In this work, we calculate the effective (saturated) mechanical properties of the Lower Goru Formation based on rock physics templates; the Backus (1962) average typically designed for layered media, combined with the empirical relations of Brown and Korringa (1975) and Wood (1955). The input data used in our rock physics modelling is based on detailed petrophysical analyses of well data. Using the saturated effective mechanical properties of the Lower Goru Formation, we generate angle-dependent reflection coefficient curves (and seismic AVA responses) based on exact and approximate solutions, for both isotropic and anisotropic reservoir scenarios. Our results suggest that the effects of lithological anisotropy are more pronounced in places with thick shale beds within reservoir sands. Conversely, angle-dependent reflection curves, and seismic AVA responses based on isotropic or anisotropic cases, give similar solutions in the presence of thin shale beds. As a corollary of this work, we present a Bayesian inversion method for the estimation of porosity in VTI media
In silico Proteome-wide Amino aCid and Elemental Composition (PACE) Analysis of Expression Proteomics Data Provides A Fingerprint of Dominant Metabolic Processes
AbstractProteome-wide Amino aCid and Elemental composition (PACE) analysis is a novel and informative way of interrogating the proteome. The PACE approach consists of in silico decomposition of proteins detected and quantified in a proteomics experiment into 20 amino acids and five elements (C, H, N, O and S), with protein abundances converted to relative abundances of amino acids and elements. The method is robust and very sensitive; it provides statistically reliable differentiation between very similar proteomes. In addition, PACE provides novel insights into proteome-wide metabolic processes, occurring, e.g., during cell starvation. For instance, both Escherichia coli and Synechocystis down-regulate sulfur-rich proteins upon sulfur deprivation, but E. coli preferentially down-regulates cysteine-rich proteins while Synechocystis mainly down-regulates methionine-rich proteins. Due to its relative simplicity, flexibility, generality and wide applicability, PACE analysis has the potential of becoming a standard analytical tool in proteomics
Effect of gender on strength gains after isometric exercise coupled with electromyographic biofeedback in knee osteoarthritis: A preliminary study
AbstractObjectiveThe objective of this trial was to evaluate the effect of gender on strength gains after five week training programme that consisted of isometric exercise coupled with electromyographic biofeedback to the quadriceps muscle.Materials and methodsForty-three (20 men and 23 women) patients with knee osteoarthritis (OA), were placed into two groups based on their gender. Both groups performed isometric exercise coupled with electromyographic biofeedback for five days a week for five weeks.ResultsBoth groups reported gains in muscle strength after five week training. However, the difference was found to be statistically insignificant between the two groups (P=0.224).ConclusionThe results suggest that gender did not affect gains in muscle strength by isometric exercise coupled with electromyographic biofeedback in patients with knee OA
Molecular and biochemical characterization of soil isolates of Aspergillus niger aggregate and an assessment of their antagonism against Rhizoctonia solani
Sixteen Aspergillus niger aggregate isolates collected from different crop fi elds were subjected to RAPDPCR using 20 Operon primers and 8 synthetic primers. Twenty-two primers led to the amplifi cation of 727 fragments ranging from 3500 bp (OPA 11) to 200 bp (primer 06). Two bands were monomorphic, while the rest were polymorphic. Three amplicons produced by OPA 16 were recorded as isolate-specifi c as 2300 bp by AnC2 and AnR3, and as 2800 bp by AnC2 only. The highest genetic similarity (0.79) was measured between AnC2 and AnR3, and the lowest (0.17) between AnC2 and AnR2. Multivariate analysis of genetic similarity revealed three major clusters, named group I, group II and group III. All isolates were ochratoxin A negative
Natural variation reveals that intracellular distribution of ELF3 protein is associated with function in the circadian clock
Natural selection of variants within the Arabidopsis thaliana circadian clock can be attributed to adaptation to varying environments. To define a basis for such variation, we examined clock speed in a reporter-modified Bay-0 x Shakdara recombinant inbred line and localized heritable variation. Extensive variation led us to identify EARLY FLOWERING3 (ELF3) as a major quantitative trait locus (QTL). The causal nucleotide polymorphism caused a short-period phenotype under light and severely dampened rhythm generation in darkness, and entrainment alterations resulted. We found that ELF3-Sha protein failed to properly localize to the nucleus, and its ability to accumulate in darkness was compromised. Evidence was provided that the ELF3-Sha allele originated in Central Asia. Collectively we showed that ELF3 protein plays a vital role in defining its light-repressor action in the circadian clock and that its functional abilities are largely dependent on its cellular localization
Right vs. left ventricular longitudinal strain for mortality prediction after transcatheter aortic valve implantation
INTRODUCTION
This study aims at exploring biventricular remodelling and its implications for outcome in a representative patient cohort with severe aortic stenosis (AS) undergoing transcatheter aortic valve implantation (TAVI).
METHODS AND RESULTS
Pre-interventional echocardiographic examinations of 100 patients with severe AS undergoing TAVI were assessed by speckle tracking echocardiography of both ventricles. Association with mortality was determined for right ventricular global longitudinal strain (RVGLS), RV free wall strain (RVFWS) and left ventricular global longitudinal strain (LVGLS). During a median follow-up of 1,367 [959-2,123] days, 33 patients (33%) died. RVGLS was lower in non-survivors [-13.9% (-16.4 to -12.9)] than survivors [-17.1% (-20.2 to -15.2); P = 0.001]. In contrast, LVGLS as well as the conventional parameters LV ejection fraction (LVEF) and RV fractional area change (RVFAC) did not differ (P = ns). Kaplan-Meier analyses indicated a reduced survival probability when RVGLS was below the -14.6% cutpoint (P < 0.001). Lower RVGLS was associated with higher mortality [HR 1.13 (95% CI 1.04-1.23); P = 0.003] independent of LVGLS, LVEF, RVFAC, and EuroSCORE II. Addition of RVGLS clearly improved the fitness of bivariable and multivariable models including LVGLS, LVEF, RVFAC, and EuroSCORE II with potential incremental value for mortality prediction. In contrast, LVGLS, LVEF, and RVFAC were not associated with mortality.
DISCUSSION
In patients with severe AS undergoing TAVI, RVGLS but not LVGLS was reduced in non-survivors compared to survivors, differentiated non-survivors from survivors, was independently associated with mortality, and exhibited potential incremental value for outcome prediction. RVGLS appears to be more suitable than LVGLS for risk stratification in AS and timely valve replacement
Hybrid Machine Learning Technique for Forecasting Dhaka Stock Market Timing Decisions
Forecasting stock market has been a difficult job for applied researchers owing to nature of facts which is very noisy and time varying. However, this hypothesis has been featured by several empirical experiential studies and a number of researchers have efficiently applied machine learning techniques to forecast stock market. This paper studied stock prediction for the use of investors. It is always true that investors typically obtain loss because of uncertain investment purposes and unsighted assets. This paper proposes a rough set model, a neural network model, and a hybrid neural network and rough set model to find optimal buy and sell of a share on Dhaka stock exchange. Investigational findings demonstrate that our proposed hybrid model has higher precision than the single rough set model and the neural network model. We believe this paper findings will help stock investors to decide about optimal buy and/or sell time on Dhaka stock exchange
Left atrial pump strain predicts long-term survival after transcatheter aortic valve implantation
BACKGROUND
This study aims at investigating left atrial (LA) deformation by left atrial reservoir (LARS) and pump strain (LAPS) and its implications for long-term survival in patients with severe aortic stenosis (AS) undergoing transcatheter aortic valve implantation (TAVI).
METHODS
Speckle tracking echocardiography was performed in 198 patients with severe AS undergoing TAVI. Association of strain parameters with cardiovascular mortality was determined.
RESULTS
Over a follow-up time of 5Â years, 49 patients (24.7%) died. LAPS was more impaired in non-survivors than survivors (PÂ =Â 0.010), whereas no difference was found for LARS (PÂ =Â 0.114), LA ejection fraction (PÂ =Â 0.241), and LA volume index (PÂ =Â 0.292). Kaplan-Meier analyses yielded a reduced survival probability according to the optimal threshold for LAPS (PÂ =Â 0.002). A more impaired LAPS was associated with increased mortality risk (HR 1.12 [95% CI 1.02-1.22]; PÂ =Â 0.014) independent of LVEF, LAVI, age, and sex. Addition of LAPS improved multivariable echocardiographic (LVEF, LAVI) and clinical (age, sex) models with potential incremental value for mortality prediction (PÂ =Â 0.013 and PÂ =Â 0.031, respectively). In contrast, LARS and LAVI were not associated with mortality.
CONCLUSIONS
In patients undergoing aortic valve replacement for severe AS, LAPS was impaired in patients dying during long-term follow-up after TAVI, differentiated survivors from non-survivors, was independently associated with long-term mortality, and yielded potential incremental value for survival prediction after TAVI. LAPS seems useful for risk stratification in severe AS and timely valve replacement
FORMULATION AND CHARACTERIZATION OF FLUCONAZOLE LOADED OLIVE OIL NANOEMULSIONS
Present study was carried out to develop and evaluate olive oil based nano-emulsion for transdermal delivery of fluconazole, a bistriazole based antifungal agent with poor water solubility and lipophilicity. Olive oil, a natural non-irritating, non-toxic proposed permeation enhancer, is known to have some antifungal activity as well. Screening of common emulsifiers like Tweens (Tween 20, tween 60, tween 80), Spans (span 60, span 80), brij 35, puronic 127, and poloxamer 188 were done based on solubility of fluconazole in these surfactants followed by their efficiency to emulsify olive oil in water. Co-emulsifiers such as glycols (polyethylene glycol 200, polyethylene glycol 400, propylene glycol), and short chain alcohols (ethanol, propanol, butanol and octanol) were also screened similarly. Tween 80 and butanol were selected as emulsifier and co-emulsifier respectively to formulate nano-emulsion by aqueous titration method. However, separation was observed after 24 hours. Therefore, span 80 was added as an auxiliary emulsifier to improve emulsification efficiency. Finally, a blend of tween 80, span 80 and butanol was optimized as emulsifier (56 % wt/wt) to emulsify 9 % wt/wt of olive oil in 33 % wt/wt water. Pseudo-ternary phase diagram was employed to identify and optimize the components. Optimized formulation based on phase separation and thermokinetic stability was characterized for globule size, size distribution, zeta potential, viscosity, refractive index and pH. Globule size analysis by zetasizer nano ZS was further confirmed by transmission electron microscopy. Permeation flux of fluconazole from optimized formulation through artificial skin was approximately three fold higher than the control. In conclusion, developed olive oil based nano-emulsion of fluconazole demonstrated promising solubility, permeability and stability.
Keywords: Fluconazole, olive oil, nano-emulsion, transdermal permeatio
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