145 research outputs found

    Pd(II)-doping studies on tris(thiourea)zinc(II) sulphate crystals: Catalytic effect of Pd(II)-doping on SHG efficiency

    Get PDF
    Single crystals of Pd(II)-doped tris(thiourea)zinc(II) sulphate (ZTS) have been grown from an aqueous solution by conventional slow evaporation solution growth technique. The characteristic functional groups have been identified by FTIR analysis. Crystal stress has been indicated by powder XRD patterns and FTIR analysis. Incorporation of dopant into the crystalline matrix during crystallization process has been evidenced by energy dispersive X-ray spectroscopy and quantified by inductively coupled plasma technique. The surface morphological changes have been observed in the doped specimen. Mechanical stability of the as-grown specimen has been analyzed by Vickers microhardness analysis. Thermal studies reveal no decomposition up to the melting point. Lattice parameters determined by single crystal XRD analysis reveal only minor variations as a result of low doping. Pd(II) doping has a catalytic effect on the second harmonic generation efficiency improvement of zinc thiourea complex

    Sea turtle research and conservation

    Get PDF
    Five species of sea turtles are known from the Indian Seas and all are today protected and are placed in Schedule I of the Indian Wildlife (Protection) Act, 1972. The Convention of International Trade in Endangered Species of Wild Fauna and Flora (CITES) which prohibits trade in turtle products places these species in Appendix I of the Convention. AUfive species have very wide distribution and there has been a traditional subsistence fishery for the green turtle Chelonia mydas along the Tuticorin Coast which has now been phased out. A new event in the recent past was the explosive development of an outlet for the olive ridley in the Calcutta-Howrah markets chiefly from the Orissa Coast, despite the Indian Wildlife (Protection) Act. This happens mainly during the mating and mass nesting of this species along the Gahirmatha Coast of Orissa and the capture is mainly in the gillnet fishing operations. This has been reported in detail in Marine Fisheries Information Service, Technical and Extension Series, No. 50 of this Institute. Incidental catch of turtles in fishing operations has been a matter of great concern and only an intensive extension programme can help to minimise the mortality from this source

    Distribution of resonances for open quantum maps

    Get PDF
    We analyze simple models of classical chaotic open systems and of their quantizations (open quantum maps on the torus). Our models are similar to models recently studied in atomic and mesoscopic physics. They provide a numerical confirmation of the fractal Weyl law for the density of quantum resonances of such systems. The exponent in that law is related to the dimension of the classical repeller (or trapped set) of the system. In a simplified model, a rigorous argument gives the full resonance spectrum, which satisfies the fractal Weyl law. For this model, we can also compute a quantity characterizing the fluctuations of conductance through the system, namely the shot noise power: the value we obtain is close to the prediction of random matrix theory.Comment: 60 pages, no figures (numerical results are shown in other references

    Probing composition distributions in nanoalloy catalysts with correlative electron microscopy

    Get PDF
    Alloyed nanoparticles are important functional materials and have wide applications especially in heterogeneous catalysis and electrocatalysis. Controlled synthesis of nanoalloys is desirable in order to understand their structure–property relationships and further optimize their performance. While many synthesis methods have been developed, information on the resultant composition distributions among particles is often not available, and uniformity of composition from particle-to-particle is often incorrectly assumed. Such an analysis would require extensive work on a high-resolution analytical electron microscope, which has some drawbacks and the high-resolution equipment is not always readily accessible. We hereby introduce an alternative way for composition analysis of nanoalloys via a correlative electron microscopy approach, separating the size measurement (imaging) and composition analysis between TEM and SEM instruments. Using a case study of two AuPd nanoalloys which have very similar size distributions but significantly different composition distributions and catalytic activities, we demonstrate both the necessity of performing composition distribution analysis on ultrasmall nanoalloys and the feasibility of this method. We show that a more efficient X-ray analysis on nanoalloys can be done in an SEM due to intrinsically higher ionization cross-sections from the relatively lower energy (e.g. 20 keV) electron beam and the possibility of using large probe currents and X-ray detectors with large collection angles

    Development of 11 polymorphic microsatellite markers for Xylocarpus granatum (Meliaceae) using next-generation sequencing technology

    Get PDF
    Human impacts have seriously damaged mangroves, and conservation of mangroves will require information on local and regional population genetic structures. Here, we report the development and polymorphism of eleven novel microsatellite markers, developed using next- generation sequencing on 56 samples of widespread man- grove species Xylocarpus granatum (Meliaceae) from nine populations across the Indo-West Pacific region. All loci were found to be polymorphic, with the number of alleles per locus ranging from four to 19. In a population from Sabah (Malaysia), the mean observed and expected heterozygosity per locus was 0.59 and 0.58, respectively. No null allele, significant linkage disequilibrium or deviation from Hardy–Weinberg equilibrium was detected among all loci. The eleven markers developed can be valuable tools to conservation genetics of this species across its distributional range

    Risk factors for myocardial infarction among low socioeconomic status South Indian population

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>As longevity increases, cases of myocardial infarction (MI) are likely to be more. Cardiovascular disease (CVD) is a major global health problem reaching epidemic proportions in the Indian subcontinent, also among low socio-economic status (SES) and thin individuals.</p> <p>Objectives</p> <p>The present study was undertaken to elicit risk factors for MI among low SES Southern Indians and to find out its association with body mass index (BMI).</p> <p>Materials and methods</p> <p>A case-control study of patients with MI matched against healthy control subjects was carried out in a tertiary care teaching hospital. Standard methods were followed to elicit risk factors and BMI. Chi-square and Fishers exact test for categorical versus categorical, to show relationship with risk factors were analyzed.</p> <p>Results</p> <p>A total of 949 patients (male (M) = 692 and post menopausal female (F) = 257) and 611 age and sex matched healthy controls were included. In our study, BMI was below 23 in 48.2% of patients and below 21 in 22.5%. The risk of developing MI was significantly more in males (odds ratio (OR) = 3.3, 95% confidence interval (C.I.) = 2.69-4.13), among females with post-menopausal duration (PMD) of more than or equal to 3 years (OR = 9.27, 95% C.I. = 6.36-13.50) and in those with BMI less than 23 with one or other risk factors (P = 0.002, OR = 1.38, 95% C.I. = 1.13-1.70).</p> <p>Conclusion</p> <p>BMI cannot be considered as a lone independent risk factor, as the study population had low BMI but had one or more modifiable risk factors. It would be advisable to keep BMI at least 21 kg/m<sup>2 </sup>for screening program. Health education on life style modification and programs to diagnose and control diabetes and hypertension have to be initiated at community level in order to reduce the occurrence.</p

    Multiple effects of toxins isolated from Crotalus durissus terrificus on the hepatitis C virus life cycle

    Get PDF
    Hepatitis C virus (HCV) is one of the main causes of liver disease and transplantation worldwide. Current therapy is expensive, presents additional side effects and viral resistance has been described. Therefore, studies for developing more efficient antivirals against HCV are needed. Compounds isolated from animal venoms have shown antiviral activity against some viruses such as Dengue virus, Yellow fever virus and Measles virus. In this study, we evaluated the effect of the complex crotoxin (CX) and its subunits crotapotin (CP) and phospholipase A2 (PLA2-CB) isolated from the venom of Crotalus durissus terrificus on HCV life cycle. Huh 7.5 cells were infected with HCVcc JFH-1 strain in the presence or absence of these toxins and virus was titrated by focus formation units assay or by qPCR. Toxins were added to the cells at different time points depending on the stage of virus life cycle to be evaluated. The results showed that treatment with PLA2-CB inhibited HCV entry and replication but no effect on HCV release was observed. CX reduced virus entry and release but not replication. By treating cells with CP, an antiviral effect was observed on HCV release, the only stage inhibited by this compound. Our data demonstrated the multiple antiviral effects of toxins from animal venoms on HCV life cycle

    Bruguiera hainesii, a critically endangered mangrove species, is a hybrid between B. Cylindrica and B. Gymnorhiza (Rhizophoraceae)

    Get PDF
    Bruguiera hainesii (Rhizophoraceae) is one of the two Critically Endangered mangrove species listed in the IUCN Red List of Threatened Species. Although the species is vulnerable to extinction, its genetic diversity and the evolutionary relationships with other Bruguiera species are not well understood. Also, intermediate morphological characters imply that the species might be of hybrid origin. To clarify the genetic relationship between B. hainesii and other Bruguiera species, we conducted molecular analyses including all six Bruguiera species using DNA sequences of two nuclear genes (CesA and UNK) and three chloroplast regions (intergenic spacer regions of trnL-trnF, trnS-trnG and atpB-rbcL). For nuclear DNA markers, all nine B. hainesii samples from five populations were heterozygous at both loci, with one allele was shared with B. cylindrica, and the other with B. gymnorhiza. For chloroplast DNA markers, the two haplotypes found in B. hainesii were shared only by B. cylindrica. These results suggested that B. hainesii is a hybrid between B. cylindrica as the maternal parent and B. gymnorhiza as the paternal one. Furthermore, chloroplast DNA haplotypes found in B. hainesii suggest that hybridization has occurred independently in regions where the distribution ranges of the parental species meet. As the IUCN Red List of Threatened Species currently excludes hybrids (except for apomictic plant hybrids), the conservation status of B. hainesii should be reconsidered

    Review on catalytic cleavage of C-C inter-unit linkages in lignin model compounds: Towards lignin depolymerisation

    Get PDF
    Lignin depolymerisation has received considerable attention recently due to the pressing need to find sustainable alternatives to fossil fuel feedstock to produce chemicals and fuels. Two types of interunit linkages (C–C and C–O linkages) link several aromatic units in the structure of lignin. Between these two inter-unit linkages, the bond energies of C–C linkages are higher than that of C–O linkages, making them harder to break. However, for an efficient lignin depolymerisation, both types of inter-unit linkages have to be broken. This is more relevant because of the fact that many delignification processes tend to result in the formation of additional C–C inter-unit bonds. Here we review the strategies reported for the cleavage of C–C inter-unit linkages in lignin model compounds and lignin. Although a number of articles are available on the cleavage of C–O inter-unit linkages, reports on the selective cleavage of C–C inter-unit linkages are relatively less. Oxidative cleavage, hydrogenolysis, two-step redox-neutral process, microwave assisted cleavage, biocatalytic and photocatalytic methods have been reported for the breaking of C–C inter-unit linkages in lignin. Here we review all these methods in detail, focused only on the breaking of C–C linkages. The objective of this review is to motivate researchers to design new strategies to break this strong C–C inter-unit bonds to valorise lignins, technical lignins in particular

    Antiplatelet therapy with aspirin, clopidogrel, and dipyridamole versus clopidogrel alone or aspirin and dipyridamole in patients with acute cerebral ischaemia (TARDIS): a randomised, open-label, phase 3 superiority trial

    Get PDF
    Background: Intensive antiplatelet therapy with three agents might be more effective than guideline treatment for preventing recurrent events in patients with acute cerebral ischaemia. We aimed to compare the safety and efficacy of intensive antiplatelet therapy (combined aspirin, clopidogrel, and dipyridamole) with that of guideline-based antiplatelet therapy. Methods: We did an international, prospective, randomised, open-label, blinded-endpoint trial in adult participants with ischaemic stroke or transient ischaemic attack (TIA) within 48 h of onset. Participants were assigned in a 1:1 ratio using computer randomisation to receive loading doses and then 30 days of intensive antiplatelet therapy (combined aspirin 75 mg, clopidogrel 75 mg, and dipyridamole 200 mg twice daily) or guideline-based therapy (comprising either clopidogrel alone or combined aspirin and dipyridamole). Randomisation was stratified by country and index event, and minimised with prognostic baseline factors, medication use, time to randomisation, stroke-related factors, and thrombolysis. The ordinal primary outcome was the combined incidence and severity of any recurrent stroke (ischaemic or haemorrhagic; assessed using the modified Rankin Scale) or TIA within 90 days, as assessed by central telephone follow-up with masking to treatment assignment, and analysed by intention to treat. This trial is registered with the ISRCTN registry, number ISRCTN47823388. Findings: 3096 participants (1556 in the intensive antiplatelet therapy group, 1540 in the guideline antiplatelet therapy group) were recruited from 106 hospitals in four countries between April 7, 2009, and March 18, 2016. The trial was stopped early on the recommendation of the data monitoring committee. The incidence and severity of recurrent stroke or TIA did not differ between intensive and guideline therapy (93 [6%] participants vs 105 [7%]; adjusted common odds ratio [cOR] 0·90, 95% CI 0·67–1·20, p=0·47). By contrast, intensive antiplatelet therapy was associated with more, and more severe, bleeding (adjusted cOR 2·54, 95% CI 2·05–3·16, p<0·0001). Interpretation: Among patients with recent cerebral ischaemia, intensive antiplatelet therapy did not reduce the incidence and severity of recurrent stroke or TIA, but did significantly increase the risk of major bleeding. Triple antiplatelet therapy should not be used in routine clinical practice
    corecore