1,008 research outputs found

    Quintessence and effective RN de Sitter brane geometries

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    We revisit an effective space-time torsion curvature in a second order formalism, underlying the non-linear U(1)U(1) gauge dynamics, of a two form on a D4D_4-brane in type IIA superstring theory. The formalism incorporates the significance of a global NS two form into the theory via its perturbative coupling to a dynamical two form. In particular, we explore the non-linear gauge dynamics on a D4D_4-brane in presence of a non-trivial background metric. The fact that the global modes of a NS two form in an open string theory sources the background metric on a D4D_4-brane may hint at the existence of an anti D4D_4-brane in the formalism. An effective de Sitter universe is shown to emerge on a vacuum created pair of (DDˉ)3(D{\bar D})_3-brane by a local two form at the past horizon with a Big Bang. We obtain a number of 4D de Sitter quantum black holes, including a Reissner-Nordstrom vacuum, with and without a propagating torsion. The quantum black holes are shown to be free from curvature singularity at r→0r\rightarrow 0. In a low energy limit, the nonperturbative correction sourced by a torison may seen to be insignificant. The quantum black hole undergoes an expansion in the limit and presumably identifies with the Einstein vacuum. Interestingly our analysis reveals a plausible quintessence (axion) on an anti D3D_3-brane which may source the dark energy in a D3D_3-brane universe. Arguably a brane universe moves away from its anti-brane due to the conjectured repulsive gravity underlying the quintessence. It leads to a growth in extra fifth dimension between a brane and an anti-brane which may provide a clue behind an accelerating universe observed in cosmology.Comment: 29 page

    Past, present and future of rice blast management

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    Blast disease caused by fungal pathogen Magnaporthe oryzae is the most severe disease of rice (Oryza sativa L). On an estimate it annually destroys rice, which can feed around 60 million people. Keeping in view of the importance of the disease, various management strategies like controlled use of nitrogen fertilizers, application of silica and flooding of paddy fields are the practices in use to reduce the rice blast since long time. Improved chemical methods include utilization of copper fungicides, organomercuric and organophosphorus compounds. Some antibiotics e.g., Blasticidin S and Kasugamycin and many systemic and site specific fungicides including melanin biosynthesis inhibitors and plant activators were also utilized effectively for blast management. In the recent years leaf extracts of tulsi and bael have been found effective. Due to the highly variable nature of M. oryzae, exploitation of durable host resistance has remained a challenging job for plant pathologists and breeders. Lots of efforts have been made worldwide to study the variability in the pathogen and to find out the resistance sources. To date approximately 100 R genes for blast resistance have been mapped and 20 of these genes have been cloned in rice. Now, scientists are looking forward to develop durable resistant varieties through pyramiding of quantitative trait loci and major genes. Among the biocontrol agents, different strains of Bacillus spp. and Streptomyces sindeneusis are in use. The availability of rice and M. oryzae genome sequence data are facilitating blast resistance management program to new paradigms which includes isolation and characterization of R and Avr genes, development of noble fungicides, transformed bioagents, transgenic rice and durable resistance

    Effectiveness of Hemcon Dental Dressing versus Conventional Method of Haemostasis in 40 Patients on Oral Antiplatelet Drugs

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    Objectives: The purpose of the study was to evaluate the effectiveness of the HemCon Dental Dressing (HDD) in controlling post extraction bleeding and to ascertain its role in healing of extraction wounds, as compared to control. Methods: The 40 participants in the study were all receiving oral antiplatelet therapy (OAT). A total of 80 extractions were conducted without altering the patients’ drug therapy. The extraction sites were divided into 2 groups: one group received a HDD, and the control group where the conventional method of pressure pack with sterile gauze under biting pressure (followed by suturing if required) was used to achieve haemostasis. Results: All HemCon treated sites achieved haemostasis sooner (mean = 53 seconds) than the control sites (mean = 918 seconds) which was statistically significant (P <0.001). Postoperative pain in the HDD group (1.74) was also significantly lower than in the control group (5.26) (P <0.001). Approximately 72.5% of HDD-treated sites showed significantly better postoperative healing when compared to the control site (P <0.001). Conclusion: HDD proved to be an excellent haemostatic agent that significantly shortened the bleeding time following dental extraction in patients on OAT. Additionally, HDD offered significantly improved post-operative healing of the extraction socket and less postoperative pain

    Comparative metagenomic analysis of bacterial diversity in three distantly related soils in India

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    Soil microbial diversity is a vital factor for the progression of vegetation and biogeochemical cycles in an ecosystem. It is affected by the chemical composition, soil microenvironment and anthropogenic activities. The present study investigated the effect of environmental conditions and anthropogenic activities on the bacterial diversity of three distantly related soils in India. The multiple soil samples were collected from Hospital waste sites (BTC2) with extensive anthropogenic activity, Himalayan forest soil (RM1) with low anthropogenic activity and Tso Kar Lake sediment soil samples with negligible anthropogenic activity with environmental factors such as soil pH, temperature and altitude on the bacterial diversity. The soil samples were analyzed for physico-chemical properties that suggest significant variations in pH, electrical conductivity (EC), total dissolved solids (TDS), temperature and altitude. The SEM-EDS (Scanning electron microscopy with energy-dispersive X-ray spectroscopy) analysis revealed the elemental composition of the soil samples. The bacterial diversity of three different soil samples was studied using 16S rRNA sequencing-based metagenomic analysis. The results suggested that the bacterial diversity in Hospital waste site soil samples was higher than in the other two soil samples based on chao1 (richness and evenness) analysis. The Phyla Firmicutes were more abundant in Hospital waste site soil, and Himalayan forest soil showed a higher abundance of phylum Proteobacteria (28.86%) and Actinobacteria (26.70%). Tso Kar Lake sediment soil samples showed the most abundant phylum as Proteobacteria (46.28%). The study suggests that increased anthropogenic activity increases soil bacterial diversity. It may eventually help to develop new approaches for sustainable land-use management practices.

    Study of association between C-reactive protein and albuminuria in type 2 diabetes mellitus

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    Background: Inflammatory markers are excessively produced by adipocytes in T2DM due to obesity-induced dysregulation of adipocytes. Inflammation is recognised by elevated level of inflammatory markers like C-reactive protein. It has been reported that patients with nephropathy and those with albuminuria have higher levels of inflammatory markers. Methods: Study design observational descriptive cross-sectional study. 150 subjects having age more than 30 years and less than 55 years diagnosed with type 2 diabetes mellitus were included. HbA1c, FPG, creatinine, urea, CRP, and albuminuria were analysed. Results: A strong and statistically significant correlation was seen between serum CRP levels and albuminuria levels with a p value of 0.831 and a p value of 0.00. The study group was divided into two groups with normal CRP (n=40) and elevated CRP (n=110). Average values of all parameters showed a statistically significant increase in the group with abnormal CRP levels. In the ROC analysis, an area of .957 under the curve shows a very high predictive value of 15.5 mg/l of CRP for predicting albuminuria in patients of T2DM. Conclusions: From our results, we have been able to establish a strong association as well as a predictive relationship between the level of CRP and albuminuria in T2DM. We have shown that serum CRP levels at a cut-off of 15.5 mg/l are a predictor of clinically significant albuminuria. This makes serum CRP level an effective screening tool for albuminuria

    Neural oscillators for generalization of physics-informed machine learning

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    A primary challenge of physics-informed machine learning (PIML) is its generalization beyond the training domain, especially when dealing with complex physical problems represented by partial differential equations (PDEs). This paper aims to enhance the generalization capabilities of PIML, facilitating practical, real-world applications where accurate predictions in unexplored regions are crucial. We leverage the inherent causality and temporal sequential characteristics of PDE solutions to fuse PIML models with recurrent neural architectures based on systems of ordinary differential equations, referred to as neural oscillators. Through effectively capturing long-time dependencies and mitigating the exploding and vanishing gradient problem, neural oscillators foster improved generalization in PIML tasks. Extensive experimentation involving time-dependent nonlinear PDEs and biharmonic beam equations demonstrates the efficacy of the proposed approach. Incorporating neural oscillators outperforms existing state-of-the-art methods on benchmark problems across various metrics. Consequently, the proposed method improves the generalization capabilities of PIML, providing accurate solutions for extrapolation and prediction beyond the training data

    Emerging trends in clinical implications of bio-conjugated silver nanoparticles in drug delivery

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    © 2020 Elsevier B.V. From nanopharmaceutics to renewable energy, silver nanoparticles (AgNPs) present innumerable applications in the contemporary era. However, the associated toxicity to the biosystems limits their application. Effective utilization of AgNPs, therefore, requires their surface conjugation with biologically benevolent moieties that enhance the bio-acceptability of silver-based nanosystems, and supplementary functionalities for further extension of their unique applications. The clinical importance of AgNPs was established long ago, but their clinical utilization has been explored only recently with the phenomenon of bio-conjugation. The biomolecule-conjugated AgNPs present operable solutions for tedious clinical complications of the present era, such as multidrug resistance, designing of pharmaceuticals with improved bioavailability, superior drug delivery vehicles and in situ bio imaging of important metabolites that utilize the biomolecule-anchored surface engineered AgNPs. This review epigrammatically discusses some interesting clinical applications of surface conjugated AgNPs with biomolecules such as peptides, nucleic acids, amino acids and antibodies in the current nanopharmaceutical paradigm

    Artery of Percheron Infarction as an Unusual Cause of Korsakoff’s Syndrome

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    The Korsakoff syndrome is defined as “an abnormal mental state in which memory and learning are affected out of all proportion to other cognitive functions in an otherwise alert and responsive patient.” Confabulation refers to false or erroneous memories arising, not deliberately, in the context of a neurological amnesia and is often thought of as pathognomonic of the Korsakoff syndrome. Although the exact pathophysiology is unknown, various studies have identified brain lesions in the thalami, mammillary bodies, and frontal cortex. We report a case of a 68-year-old male presenting with acute altered mental status on July 16, 2015. The neuropsychological dysfunctions included prominent Korsakoff’s syndrome, which became apparent when the altered mental status resolved. Amnesia was accompanied by prominent confabulation, disorientation, and lack of insight into his own disability. Neuroradiological data indicated that the intralaminar and dorsomedial nuclei in bilateral thalami were infarcted by occlusion of the artery of Percheron. We believe that ours is one of few reported cases of Korsakoff syndrome in a patient with infarction involving the territory of the artery of Percheron. We conclude that bilateral thalamic lesions could cause Korsakoff’s syndrome and the intralaminar and dorsomedial nuclei might be important structures in the pathogenesis of confabulation
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