44 research outputs found

    Compact relativistic geometries in f(R,G)f(R,G) gravity

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    One of the possible potential candidates for describing the universe's rapid expansion is modified gravity. In the framework of the modified theory of gravity f(R,G)f(R,G), the present work features the materialization of anisotropic matter, such as compact stars. Specifically, to learn more about the physical behavior of compact stars, the radial, and tangential pressures as well as the energy density of six stars namely HerX1Her X-1, SAXJ1808.43658SAXJ1808.4-3658, 4U1820304U1820-30, PSRJ16142230PSR J 1614 2230, VELAX1VELA X-1, and CenX3Cen X-3 are calculated. Herein, the modified theory of gravity f(R,G)f(R,G) is disintegrated into two parts i.e. the tanh\tanh hyperbolic f(R)f(R) model and the three different f(G)f(G) model. The study focuses on graphical analysis of compact stars wherein the stability aspects, energy conditions, and anisotropic measurements are mainly addressed. Our calculation revealed that, for the positive value of parameter n of the model f(G)f(G), all the six stars behave normally.Comment: Some changes have been made. " To appear in International Journal of Geometric Methods in Modern Physics

    Evaluation of allelopathic potential of some selected medicinal species

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    Laboratory trials were made to evaluate the allelopathic potential of selected medicinal species. The aqueous extracts bioassay on two test plants (wheat and pea) was carried out through filter paper method. Toxicity and non toxicity was assessed by recording their effects on germination and percentage growth of radicle and plumule of test plants. The trials were replicated three times in Randomized Complete Split Block Design. The data was analyzed by using software SPSS v II. The results suggested that Sonchus asper and Melilotus officinalis stimulate the growth of wheat (Triticum aestivum) up to 150% of plumule and 40% of radicle. These species had significantly enhanced effect on the percentage growth of test plant. The inhibitory effect was more on the wheat, by aqueous extractions of Sisymbrium irio, Cannabis sativus and Oxalis corniculata. The growth of wheat was more enhanced in the aqueous extractions of Gallium aperine and Ageratum conizoides, almost 150% of radicle. But the most inhibitory and retarded effect was observed in case of S. irio, O. corniculata, Rumex dentatus and Parthenium hysterophorus.Key words: Allelopathy, medicinal species, filter paper

    Calpastatin (CAST) gene polymorphism in Kajli, Lohi and Thalli sheep breeds

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    Calpastatin-encoding gene (<i>CAST</i>) is located on the fifth chromosome of sheep and it plays an  important role in the development of muscles and in meat tenderness. The present study was conducted to  investigate a calpastatin (CAST) gene polymorphism in Pakistani Thalli, Lohi and Kajli sheep breed. Random blood samples were collected from 300 animals (100 samples from each Thalli, Lohi and Kajli breeds).  Genomic DNA was extracted using phenol-chloroform extraction method. A 622 bp CAST gene segment (exon 1C/1D region) was amplified by polymerase chain reaction (PCR) using ovine specific primers. Restriction  fragment length polymorphisms (RFLPs) in the amplified fragments were studied using Msp1 restriction  enzyme. Frequencies of MM, MN and NN genotypes were found to be 77, 20 and 3% in Lohi breed and 68, 26 and 6% in Kajli breed respectively. In Thalli sheep, only the MM (80%) and MN (20%) genotypes were  detected. Chi-Square test (p < 0.05) showed that all the three populations used in this study were in Hardy-Weinberg equilibrium. By comparing the results of this study with those of previous studies, it seems that the MM genotype is the dominant genotype and the M allele is the dominant allele in small ruminant breeds belonging to different geographical locations.Key words: Thalli, Lohi, CAST gene, Kajli, polymorphism, Msp1, PCR-RFLP

    Reduced Lung-Cancer Mortality with Volume CT Screening in a Randomized Trial

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    BACKGROUND There are limited data from randomized trials regarding whether volume-based, low-dose computed tomographic (CT) screening can reduce lung-cancer mortality among male former and current smokers. METHODS A total of 13,195 men (primary analysis) and 2594 women (subgroup analyses) between the ages of 50 and 74 were randomly assigned to undergo CT screening at T0 (baseline), year 1, year 3, and year 5.5 or no screening. We obtained data on cancer diagnosis and the date and cause of death through linkages with national registries in the Netherlands and Belgium, and a review committee confirmed lung cancer as the cause of death when possible. A minimum follow-up of 10 years until December 31, 2015, was completed for all participants. RESULTS Among men, the average adherence to CT screening was 90.0%. On average, 9.2% of the screened participants underwent at least one additional CT scan (initially indeterminate). The overall referral rate for suspicious nodules was 2.1%. At 10 years of follow-up, the incidence of lung cancer was 5.58 cases per 1000 personyears in the screening group and 4.91 cases per 1000 person-years in the control group; lung-cancer mortality was 2.50 deaths per 1000 person-years and 3.30 deaths per 1000 person-years, respectively. The cumulative rate ratio for death from lung cancer at 10 years was 0.76 (95% confidence interval [CI], 0.61 to 0.94; P = 0.01) in the screening group as compared with the control group, similar to the values at years 8 and 9. Among women, the rate ratio was 0.67 (95% CI, 0.38 to 1.14) at 10 years of follow-up, with values of 0.41 to 0.52 in years 7 through 9. CONCLUSIONS In this trial involving high-risk persons, lung-cancer mortality was significantly lower among those who underwent volume CT screening than among those who underwent no screening. There were low rates of follow-up procedures for results suggestive of lung cancer. (Funded by the Netherlands Organization of Health Research and Development and others; NELSON Netherlands Trial Register number, NL580.)

    Prognostic model to predict postoperative acute kidney injury in patients undergoing major gastrointestinal surgery based on a national prospective observational cohort study.

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    Background: Acute illness, existing co-morbidities and surgical stress response can all contribute to postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery. The aim of this study was prospectively to develop a pragmatic prognostic model to stratify patients according to risk of developing AKI after major gastrointestinal surgery. Methods: This prospective multicentre cohort study included consecutive adults undergoing elective or emergency gastrointestinal resection, liver resection or stoma reversal in 2-week blocks over a continuous 3-month period. The primary outcome was the rate of AKI within 7 days of surgery. Bootstrap stability was used to select clinically plausible risk factors into the model. Internal model validation was carried out by bootstrap validation. Results: A total of 4544 patients were included across 173 centres in the UK and Ireland. The overall rate of AKI was 14·2 per cent (646 of 4544) and the 30-day mortality rate was 1·8 per cent (84 of 4544). Stage 1 AKI was significantly associated with 30-day mortality (unadjusted odds ratio 7·61, 95 per cent c.i. 4·49 to 12·90; P < 0·001), with increasing odds of death with each AKI stage. Six variables were selected for inclusion in the prognostic model: age, sex, ASA grade, preoperative estimated glomerular filtration rate, planned open surgery and preoperative use of either an angiotensin-converting enzyme inhibitor or an angiotensin receptor blocker. Internal validation demonstrated good model discrimination (c-statistic 0·65). Discussion: Following major gastrointestinal surgery, AKI occurred in one in seven patients. This preoperative prognostic model identified patients at high risk of postoperative AKI. Validation in an independent data set is required to ensure generalizability

    Intraperitoneal drain placement and outcomes after elective colorectal surgery: international matched, prospective, cohort study

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    Despite current guidelines, intraperitoneal drain placement after elective colorectal surgery remains widespread. Drains were not associated with earlier detection of intraperitoneal collections, but were associated with prolonged hospital stay and increased risk of surgical-site infections.Background Many surgeons routinely place intraperitoneal drains after elective colorectal surgery. However, enhanced recovery after surgery guidelines recommend against their routine use owing to a lack of clear clinical benefit. This study aimed to describe international variation in intraperitoneal drain placement and the safety of this practice. Methods COMPASS (COMPlicAted intra-abdominal collectionS after colorectal Surgery) was a prospective, international, cohort study which enrolled consecutive adults undergoing elective colorectal surgery (February to March 2020). The primary outcome was the rate of intraperitoneal drain placement. Secondary outcomes included: rate and time to diagnosis of postoperative intraperitoneal collections; rate of surgical site infections (SSIs); time to discharge; and 30-day major postoperative complications (Clavien-Dindo grade at least III). After propensity score matching, multivariable logistic regression and Cox proportional hazards regression were used to estimate the independent association of the secondary outcomes with drain placement. Results Overall, 1805 patients from 22 countries were included (798 women, 44.2 per cent; median age 67.0 years). The drain insertion rate was 51.9 per cent (937 patients). After matching, drains were not associated with reduced rates (odds ratio (OR) 1.33, 95 per cent c.i. 0.79 to 2.23; P = 0.287) or earlier detection (hazard ratio (HR) 0.87, 0.33 to 2.31; P = 0.780) of collections. Although not associated with worse major postoperative complications (OR 1.09, 0.68 to 1.75; P = 0.709), drains were associated with delayed hospital discharge (HR 0.58, 0.52 to 0.66; P &lt; 0.001) and an increased risk of SSIs (OR 2.47, 1.50 to 4.05; P &lt; 0.001). Conclusion Intraperitoneal drain placement after elective colorectal surgery is not associated with earlier detection of postoperative collections, but prolongs hospital stay and increases SSI risk

    Development of high performance amine functionalized zeolitic imidazolate framework (zif-8)/cellulose triacetate (CTA) mixed matrix membranes for CO2/CH4 separation

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    High cost and complex fabrication process of inorganic membranes and lower position of pristine polymeric membranes in the Robeson upper bound curve urged the researchers to develop mixed matrix membranes (MMMs). Cellulose acetate being most commercially used polymer, dominates the market of CO2 separation mainly because of low cost and environmental friendly resource. In the present study, MMMs consists of amine functionalized zeolitic imidazolate framework (NH2-ZIF-8) and cellulose triacetate were fabricated for the first time. NH2-ZIF-8 was used as a filler because the pore size of ZIF-8 is between the kinetic diameter of separating gases (CO2 and CH4). Moreover, NH2 group attached on the surface of ZIF-8 has affinity with condensable gases like CO2. Morphology, crystallinity, tensile strength and functional groups of fabricated membranes were investigated using different analytical techniques. Results revealed that the increase of feed pressure has increased CO2 permeability and decreased permselectivity. However, improvements in gas separation performance were observed with the addition of nanofiller. Best position in Robeson's upper bound curve at 4 bar was obtained with 10 wt% loading with CO2 permeability and CO2/CH4 permselectivity of 218 barrer and 13.84, respectively. The improvement in the gas separation performance with loading is attributed to the increased diffusion coefficients as well as solubility coefficients, which was increased to 33% and 3.8%, respectively

    Chemically processed CdTe thin films for potential applications in solar cells – Effect of Cu doping

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    Thin films of cadmium telluride (CdTe) have attained the attention of researchers due to the potential application in solar cells. However, cost-effective fabrication of solar cells based on thin films along with remarkable efficiency and control over optical properties is still a challenging task. This study presents an analysis of the structural, optical and electrical properties of undoped and Cu-doped CdTe thin films fabricated on ITO coated glass substrates using an electrodeposition process with a focus on practical applications. Electrolytes of cadmium (Cd), tellurium (Te) and copper (Cu) are prepared with a low molarity of 0.1 M. Thin films are deposited by keeping current density in the range of 0.12–0.3 mA/cm2. Copper doping is varied (2-10 wt%) for the optimized sample. X-ray diffraction crystallography indicates that both undoped CdTe and Cu-doped CdTe films crystallize into a dominant hexagonal lattice. Direct energy band gap is observed for both undoped and doped conditions. The study revealed a drop in the optical band gap energy to ∼1.46 eV with the increase in doping (Cu) concentration from 2 to 10 wt%. Increase in mobility and conductivity is observed with the increase in current density of the deposited undoped CdTe thin films. Whereas, Cu doping of 6 wt% produced thin films with acceptable mobility and conductivity for the doped samples. Furthermore, photoluminescence (PL) spectroscopy unveiled a multitude of emission peaks encompassing the visible spectrum, arising from the combination of electrons and holes through both direct and indirect recombination processes. Findings of this study suggest that chemically produced CdTe thin films would be suitable for use as low-cost applications pertaining to solar cells
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