143 research outputs found

    Accessible and inaccessible quantum coherence in relativistic quantum systems

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    The quantum coherence of a multipartite system is investigated when some of the parties are moving with constant acceleration. Due to relativistic motion the quantum coherence is divided into two parts as accessible and inaccessible coherence. First we investigate tripartite systems, considering both GHZ and W-states. We find that the quantum coherence of these states does not vanish in the limit of infinite acceleration, rather asymptoting to a non-zero value. These results hold for both single- and two-qubit relativistic motion. In the GHZ and W states the coherence is distributed as correlations between the qubits and is known as global coherence. But quantum coherence can also exist due to the superposition within a qubit, the local coherence. To study the properties of local coherence we investigate separable state. The GHZ state, W-state and separable states contain only one type of coherence. Next we consider the WWˉW \bar{W} and star states in which both local and global coherences coexist. We find that under relativistic motion both local and global coherence show similar qualitative behaviour. Finally we derive analytic expressions for the quantum coherence of NN-partite GHZ and W states where n<Nn<N qubits are subject to relativistic motion. We find that the quantum coherence of a multipartite GHZ state falls exponentially with the number of accelerated qubits, whereas for multipartite W-states the quantum coherence decreases only polynomially. We conclude that W-states are more robust to Unruh decoherence and discuss some potential applications in satellite-based quantum communication and black hole physics.Comment: 18 page

    Faunal richness and the checklist of Indian mosquitoes (Diptera: Culicidae)

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    A review of published studies revealed that the Indian mosquito fauna comprises 393 species in 49 genera and 41 subgenera. The subfamily Anophelinae contains 61 species in one genus followed by Culicinae with 332 species in 11 tribes and 48 genera. The tribe Aedini (subfamily Culicinae) contains the highest number of species (176 species in 33 genera and two groups of incertae sedis; i.e., “Aedes” sensu auctorum and “Ochlerotatus” sensu auctorum). With the recent taxonomic changes in tribe Aedini, the Indian mosquito genera have gone up from 22 to 49. Changes to the Indian Aedini fauna subsequent to the reclassification of tribe Aedini are discussed. A total of 31 species are currently recognized in India for transmitting various mosquito-borne agents of human diseases. A checklist for the Indian mosquito species is presented and the need for a comprehensive study is emphasized

    DNA barcodes can distinguish species of Indian mosquitoes (Diptera: Culicidae

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    ABSTRACT Species identiĂžcation of mosquitoes (Diptera: Culicidae) based on morphological characteristics remains often difĂžcult in Ăželd-collected mosquito specimens in vector-borne disease surveillance programs. The use of DNA barcodes has been proposed recently as a tool for identiĂžcation of the species in many diverse groups of animals. However, the efĂžcacy of this tool for mosquitoes remains unexplored. Hence, a study was undertaken to construct DNA barcodes for several species of mosquitoes prevalent in India, which included major vector species. In total, 111 specimens of mosquitoes belonging to 15 genera, morphologically identiĂžed to be 63 species, were used. This number also included multiple specimens for 22 species. DNA barcode approach based on DNA sequences of mitochondrial cytochrome oxidase gene sequences could identify 62 species among these, in conĂžrmation with the conventional taxonomy. However, two closely related species, Ochlerotatus portonovoensis (Tiwari &amp; Hiriyan) and Ochlerotatus wardi (Reinert) could not be identiĂžed as separate species based on DNA barcode approach, their lineages indicating negligible genetic divergence (Kimura two-parameter genetic distance Ď­ 0.0043)

    Metabolic profile reflects stages of fibrosis in patients with non-alcoholic fatty liver disease

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    Nonalcoholic fatty liver disease (NAFLD) is a leading cause of chronic liver disease worldwide, with fibrosis stage being the main predictor for clinical outcomes. Here, we present the metabolic profile of NAFLD patients with regards to fibrosis progression. We included all consecutive new referrals for NAFLD services between 2011 and 2019. Demographic, anthropometric and clinical features and noninvasive markers of fibrosis were recorded at baseline and at follow-up. Significant and advanced fibrosis were defined using liver stiffness measurement (LSM) as LSM ≥ 8.1 kPa and LSM ≥ 12.1 kPa, respectively. Cirrhosis was diagnosed either histologically or clinically. Fast progressors of fibrosis were defined as those with delta stiffness ≥ 1.03 kPa/year (25% upper quartile of delta stiffness distribution). Targeted and untargeted metabolic profiles were analysed on fasting serum samples using Proton nuclear magnetic resonance (1H NMR). A total of 189 patients were included in the study; 111 (58.7%) underwent liver biopsy. Overall, 11.1% patients were diagnosed with cirrhosis, while 23.8% were classified as fast progressors. A combination of metabolites and lipoproteins could identify the fast fibrosis progressors (AUROC 0.788, 95% CI: 0.703–0.874, p < 0.001) and performed better than noninvasive markers. Specific metabolic profiles predict fibrosis progression in patients with nonalcoholic fatty liver disease. Algorithms combining metabolites and lipids could be integrated in the risk-stratification of these patients

    Genetic analysis of patients with Fuchs endothelial corneal dystrophy in India

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    <p>Abstract</p> <p>Background</p> <p>Mutations in <it>COL8A2 </it>gene which encodes the collagen alpha-2 (VIII) chain have been identified in both familial and sporadic cases of Fuchs endothelial corneal dystrophy (FECD). Heterozygous mutations in the <it>SLC4A11 </it>gene are also known to cause late-onset FECD. Therefore we screened for <it>COL8A2</it>, <it>SLC4A11 </it>gene variants in Indian FECD patients.</p> <p>Methods</p> <p>Eighty patients with clinically diagnosed FECD and 100 age matched normal individuals were recruited. Genomic DNA was isolated from peripheral blood leukocytes. Mutations in <it>COL8A2</it>, <it>SLC4A11 </it>coding regions were screened using bi-directional sequencing. Fischer's exact test or Pearson's chi squared test were used to predict the statistical association of genotypes with the phenotype.</p> <p>Results</p> <p>Screening of <it>COL8A2 </it>gene revealed 2 novel c.1610G>A, c.1643A>G and 3 reported variations c.112G>A, c.464G>A and c.1485G>A. In <it>SLC4A11 </it>gene, novel c.1659C>T, c.1974C>T and reported c.405G>A, c.481A>C and c.639G>A variants were identified. However all the variations in both the genes were also present in unaffected controls.</p> <p>Conclusions</p> <p>This is the first study analysing <it>COL8A2 </it>gene in Indian patients with FECD. No pathogenic mutations were identified in <it>COL8A2</it>. Merely silent changes, which showed statistically insignificant association with FECD, were identified in the screening of <it>SLC4A11 </it>gene. These results suggest that <it>COL8A2</it>, <it>SLC4A11 </it>genes may not be responsible for FECD in patients examined in this study.</p

    Utilisation of an operative difficulty grading scale for laparoscopic cholecystectomy

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    Background A reliable system for grading operative difficulty of laparoscopic cholecystectomy would standardise description of findings and reporting of outcomes. The aim of this study was to validate a difficulty grading system (Nassar scale), testing its applicability and consistency in two large prospective datasets. Methods Patient and disease-related variables and 30-day outcomes were identified in two prospective cholecystectomy databases: the multi-centre prospective cohort of 8820 patients from the recent CholeS Study and the single-surgeon series containing 4089 patients. Operative data and patient outcomes were correlated with Nassar operative difficultly scale, using Kendall’s tau for dichotomous variables, or Jonckheere–Terpstra tests for continuous variables. A ROC curve analysis was performed, to quantify the predictive accuracy of the scale for each outcome, with continuous outcomes dichotomised, prior to analysis. Results A higher operative difficulty grade was consistently associated with worse outcomes for the patients in both the reference and CholeS cohorts. The median length of stay increased from 0 to 4 days, and the 30-day complication rate from 7.6 to 24.4% as the difficulty grade increased from 1 to 4/5 (both p < 0.001). In the CholeS cohort, a higher difficulty grade was found to be most strongly associated with conversion to open and 30-day mortality (AUROC = 0.903, 0.822, respectively). On multivariable analysis, the Nassar operative difficultly scale was found to be a significant independent predictor of operative duration, conversion to open surgery, 30-day complications and 30-day reintervention (all p < 0.001). Conclusion We have shown that an operative difficulty scale can standardise the description of operative findings by multiple grades of surgeons to facilitate audit, training assessment and research. It provides a tool for reporting operative findings, disease severity and technical difficulty and can be utilised in future research to reliably compare outcomes according to case mix and intra-operative difficulty
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