Publications by authors named "Pranab Das"

110 Publications

A New Spin-Correlated Plasmon in Novel Highly Oriented Single-Crystalline Gold Quantum Dots.

Nano Lett 2021 Sep 9. Epub 2021 Sep 9.

Advanced Research Initiative for Correlated-Electron Systems (ARiCES), Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117551, Singapore.

A concept of spin plasmon, a collective mode of spin-density, in strongly correlated electron systems has been proposed since the 1930s. It is expected to bridge between spintronics and plasmonics by strongly confining the photon energy in the subwavelength scale within single magnetic-domain to enable further miniaturizing devices. However, spin plasmon in strongly correlated electron systems is yet to be realized. Herein, we present a new spin correlated-plasmon at room temperature in novel Mott-like insulating highly oriented single-crystalline gold quantum-dots (HOSG-QDs). Interestingly, the spin correlated-plasmon is tunable from the infrared to visible, accompanied by spectral weight transfer yielding a large quantum absorption midgap state, disappearance of low-energy Drude response, and transparency. Supported with theoretical calculations, it occurs due to an interplay of surprisingly strong electron-electron correlations, s-p hybridization and quantum confinement in the s band. The first demonstration of the high sensitivity of spin correlated-plasmon in surface-enhanced Raman spectroscopy is also presented.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.nanolett.0c05004DOI Listing
September 2021

Moving Dirac nodes by chemical substitution.

Proc Natl Acad Sci U S A 2021 Aug;118(33)

Laboratoire de Physique des Solides, Université Paris-Saclay, CNRS, 91405 Orsay, France;

Dirac fermions play a central role in the study of topological phases, for they can generate a variety of exotic states, such as Weyl semimetals and topological insulators. The control and manipulation of Dirac fermions constitute a fundamental step toward the realization of novel concepts of electronic devices and quantum computation. By means of Angle-Resolved Photo-Emission Spectroscopy (ARPES) experiments and ab initio simulations, here, we show that Dirac states can be effectively tuned by doping a transition metal sulfide, [Formula: see text], through Co/Ni substitution. The symmetry and chemical characteristics of this material, combined with the modification of the charge-transfer gap of [Formula: see text] across its phase diagram, lead to the formation of Dirac lines, whose position in k-space can be displaced along the [Formula: see text] symmetry direction and their form reshaped. Not only does the doping x tailor the location and shape of the Dirac bands, but it also controls the metal-insulator transition in the same compound, making [Formula: see text] a model system to functionalize Dirac materials by varying the strength of electron correlations.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1073/pnas.2108617118DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8379913PMC
August 2021

Molecular characterization of porcine group A rotavirus to contain piglet diarrhea for productivity enhancement in North East India.

Virusdisease 2021 Apr 10:1-6. Epub 2021 Apr 10.

Gauhati University, Guwahati, Assam 781014 India.

Gastrointestinal tract infections with acute diarrhea are indeed a serious cause of concern that held back the swine industry of North East India and among the various etiological agents causing the disease, group A rotavirus is the most common. In this regard, molecular characterization of the viral strains circulating in the region is of utmost importance for a strategic approach to control the disease. Thus, in the present study, diarrheic fecal samples from piglets of Tripura and Assam were evaluated for genotypic characterization of VP7 and VP4 gene of the virus. The samples positive for group A rotavirus were subjected to G and P type determination by nested- multiplex RT PCR as well as nucleotide sequencing of VP7 and VP4 gene. Nested- multiplex RT PCR revealed the presence of porcine group A rotavirus in the genotypic combination of G1P[6], G3P[6], G8P[6] and G4P[6] in the two states of North East India. Nucleotide sequencing of VP7 and VP4 genes however, revealed emergence of an unusual genotypic combination G26P[13]. VP7 and VP4 nucleotide and its deduced amino acid sequences when compared with global isolates, showed that the present strains shared closest similarity to the porcine rotavirus strain TJ4-1from Japan and hp140 from Eastern India. Identification of a novel genotype G26P[13] in the RVA infected pig population of Tripura and Assam, suggested presence of a greater diversity in rotavirus strains in the region. Thus, it evokes the need for continuous monitoring to assess and consider the strain variability in the design of a suitable vaccine candidate against the virus.

Supplementary Information: The online version of this article (10.1007/s13337-021-00659-6) contains supplementary material, which is available to authorized users.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s13337-021-00659-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8035605PMC
April 2021

Retinopathy of prematurity in a level II neonatal care unit of a district of West Bengal: A retrospective analysis of 5 years.

Indian J Public Health 2020 Oct-Dec;64(4):398-401

Medical Officer in-Charge, Special Newborn Care Unit, MR Bangur Hospital, Kolkata, West Bengal, India.

Retinopathy of prematurity (ROP), particularly severe ROP is a health concern. The study is aimed to ascertain the magnitude, profile, and outcome of ROP over 5 years at a level II neonatal unit in a district of West Bengal. From 2012 to 2016, a total of 691 newborns with birth weight (BW) <2000 g and/or gestational age < 35 weeks of a district level II neonatal care unit were screened for ROP. Retrospective analysis of these screened babies was performed using the principles of descriptive and inferential statistics. Overall, 38.5% of newborns had any stage ROP and13.2% severe ROP. Two-thirds of babies with severe ROP were <1250 g of BW. About 16.2% of the ROP cases suffered from aggressive posterior ROP (APROP). Oxygen and prematurity were found as significant risk factors. Substantially high occurrence of severe ROP and APROP warrants appropriate measures. Timely screening and intervention with referral to the neonatal ROP unit can improve the scenario.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.4103/ijph.IJPH_336_19DOI Listing
December 2020

Identification of Arctic Food Fish Species for Anthropogenic Contaminant Testing Using Geography and Genetics.

Foods 2020 Dec 8;9(12). Epub 2020 Dec 8.

Department of Biology, Queen's University, Kingston, ON K7L 3N6, Canada.

The identification of food fish bearing anthropogenic contaminants is one of many priorities for Indigenous peoples living in the Arctic. Mercury (Hg), arsenic (As), and persistent organic pollutants including polychlorinated biphenyls (PCBs) are of concern, and these are reported, in some cases for the first time, for fish sampled in and around King William Island, located in Nunavut, Canada. More than 500 salmonids, comprising Arctic char, lake trout, lake whitefish, and ciscoes, were assayed for contaminants. The studied species are anadromous, migrating to the ocean to feed in the summers and returning to freshwater before sea ice formation in the autumn. Assessments of muscle Hg levels in salmonids from fishing sites on King William Island showed generally higher levels than from mainland sites, with mean concentrations generally below guidelines, except for lake trout. In contrast, mainland fish showed higher means for As, including non-toxic arsenobetaine, than island fish. Lake trout were highest in As and PCB levels, with salmonid PCB congener analysis showing signatures consistent with the legacy of cold-war distant early warning stations. After DNA-profiling, only 4-32 Arctic char single nucleotide polymorphisms were needed for successful population assignment. These results support our objective to demonstrate that genomic tools could facilitate efficient and cost-effective cluster assignment for contaminant analysis during ocean residency. We further suggest that routine pollutant testing during the current period of dramatic climate change would be helpful to safeguard the wellbeing of Inuit who depend on these fish as a staple input to their diet. Moreover, this strategy should be applicable elsewhere.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/foods9121824DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7764770PMC
December 2020

Stimuli-responsive aggregation-induced fluorescence in a series of biphenyl-based Knoevenagel products: effects of substituent active methylene groups on π-π interactions.

Acta Crystallogr B Struct Sci Cryst Eng Mater 2019 Oct 31;75(Pt 5):775-783. Epub 2019 Aug 31.

Department of Chemistry, Gauhati University, Guwahati, Assam 781014, India.

A series of three biphenyl-based Knoevenagel products (denoted 1a, 1b, 1c) with active methylene groups has been synthesized. Compounds 1a and 1b show strong solid-state fluorescence, whereas 1c displays low emission. Effects of substituent groups in condensed phase packing of the molecules have been investigated and correlated with their photophysical properties. Interestingly, compound 1a exhibits mechanofluorochromism with emission color changes from yellow to green (wavelength shift of 40 nm) after mechanical grinding. Furthermore, fluorescence of 1a and 1b is turned off under alkaline conditions, making them potential candidates for aggregation-enhanced emission-based pH sensors.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1107/S2052520619009156DOI Listing
October 2019

Giant piezoelectricity in oxide thin films with nanopillar structure.

Science 2020 07;369(6501):292-297

Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), 138634 Singapore.

High-performance piezoelectric materials are critical components for electromechanical sensors and actuators. For more than 60 years, the main strategy for obtaining large piezoelectric response has been to construct multiphase boundaries, where nanoscale domains with local structural and polar heterogeneity are formed, by tuning complex chemical compositions. We used a different strategy to emulate such local heterogeneity by forming nanopillar regions in perovskite oxide thin films. We obtained a giant effective piezoelectric coefficient [Formula: see text] of ~1098 picometers per volt with a high Curie temperature of ~450°C. Our lead-free composition of sodium-deficient sodium niobate contains only three elements (Na, Nb, and O). The formation of local heterogeneity with nanopillars in the perovskite structure could be the basis for a general approach to designing and optimizing various functional materials.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1126/science.abb3209DOI Listing
July 2020

Cost-effectiveness and Outcomes with Early or Same-Day Discharge After Elective Percutaneous Coronary Intervention.

Curr Cardiol Rep 2020 05 19;22(6):42. Epub 2020 May 19.

Division of Cardiology, Department of Internal Medicine, University of Tennessee Health Sciences Center, Memphis, TN, USA.

Purpose Of Review: Shorter hospital stay after percutaneous coronary intervention (PCI) can provide economic advantage. Same-day discharge (SDD) after transradial PCI is thought to reduce the cost of care while maintaining the quality and safety. This review summarizes the current knowledge of the benefits and safety of this concept.

Recent Findings: Increase in rate of transradial PCI over the last two decades has resulted in recent growth in rate of acceptance of SDD after a successful procedure. SDD is shown to result in savings of $3500 to $5200 per procedure with comparable adverse event rate of traditional discharge processes. SDD after PCI is shown to be safe and results in cost advantage maintaining the safety profile. The acceptance rate of SDD is still not optimum, and further market penetration of SDD practice would be achieved only if the institutional and operator preference barriers are addressed.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s11886-020-01286-1DOI Listing
May 2020

Optical constants and absorption properties of Te and TeO thin films in the 13-14 nm spectral range.

Opt Express 2020 Apr;28(9):12922-12935

Undesired mask-induced effects caused by thick absorber layers in EUV photomasks reduce the quality of the projected patterns at the wafer stage in EUV photolithography scanners. New materials with better absorption properties than the state-of-the-art absorbers, TaN and TaBN, are required to mitigate these effects. In this work, we investigated the optical properties (δ and k) of Te and TeO films in the 13-14 nm range, and the absorption properties of these two materials at 13.5 nm. δ and k are obtained through fitting experimental values of reflectivity versus angle of incidence in the EUV range. We follow a methodology which combines different characterization techniques (X-ray reflectivity, EUV reflectivity, and X-ray photoemission spectroscopy) to reduce the number of free parameters in models and hence, increase the reliability of the optical constants obtained. At 13.5 nm, we obtain δ=0.03120, k = 0.07338 for Te, and δ=0.04099, k = 0.06555 for TeO. To experimentally verify the absorption properties of these materials, different thicknesses of Te and TeO films are cast on top of a state-of-the-art mask-quality EUV multilayer with 66.7% reflectivity at 13.5 nm. We found that a reflectivity of ∼0.7% can be attained with either 32.4 nm of Te, or 34.7 nm of TeO, greatly surpassing the absorption properties of TaN and TaBN. The morphology and surface roughness of the Te and TeO films deposited on the multilayer are also investigated.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1364/OE.381883DOI Listing
April 2020

Uterine intravenous leiomyomatosis with femoral vein, intracaval, intracardiac and pulmonary artery extension.

Future Cardiol 2020 01 26;16(1):27-32. Epub 2019 Nov 26.

Division of Cardiovascular Diseases, University of Tennessee Health Science Center, Memphis, TN 38163, USA.

We report a 54-year-old female with recently diagnosed multiple cardiac thrombi and pulmonary embolism that was treated with thrombolytics and anticoagulants. She presented again with worsening dyspnea and was found to have persistent large cardiac thrombi on echocardiogram. Surgical findings revealed a single right atrial mass originating from inferior vena cava and extending into the pulmonary artery. The mass was successfully removed. Final pathology revealed a benign smooth muscle and vascular mass with estrogen and progesterone receptor positivity favoring uterine intravenous leiomyoma. She was discharged on warfarin and leuprolide therapy. This diagnosis requires a high index of suspicion, especially in a middle-aged woman with right atrial mass and history of an existing leiomyoma, hysterectomy or myomectomy.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.2217/fca-2019-0002DOI Listing
January 2020

Identification and expression profiling of MSY genes of yak for bull fertility.

J Genet 2019 06;98(2)

Indian Council of Agricultural Research-National Research Centre on Yak, West Kameng, India.

Yak () is a unique bovine species and considered as lifeline of highlanders. The male subfertility in yak is a matter of concern that causes huge economic loses. The spermatogenesis and male reproduction machinery are critically governed by Y-linked genes which tend to acquire necessary information in the course of evolution. The Y-linked fertility genes are present in multiple copies with testis-limited expression. To understand this novel complexity, 12 male-specific region of Y chromosome (MSY) genes have been studied in the yak. Targeted genes are amplified in male and female genomic DNA and confirmed the male derived specificity. Moreover, testis and sperm-specific expressions of MSY genes are distinct among different tissues. The quantitative polymerase chain reaction results validate the expression pattern of these genes in various tissues with predominant expression intestis and sperm. The sequencing of resultant yak MSY genes gives significant result and shows similarity with cattle (), but few nucleotide mismatches define the proposition of infertile male in the F hybrid of cattle and yak. The identified MSY genes can be used to establish male-specific characteristics and to differentiate male and female yak genotypically. Further, these genes may act as valuable resources to understand the capacity of spermatogenesis, embryogenesis, cellular growth, azoospermia and malesubfertility in the yak.
View Article and Find Full Text PDF

Download full-text PDF

Source
June 2019

Multiple Granulomas of Ocular Toxocariasis in an Immunocompetent Male.

Ocul Immunol Inflamm 2020 3;28(1):111-115. Epub 2019 Jun 3.

Advanced Eye Center, Department of Ophthalmology, Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh, India.

A 25-year-old male presented with unilateral panuveitis with multiple voluminous elevated retinal lesions along with subretinal fluid and exudation. An extensive laboratory work-up was done, and a clinical suspicion of viral retinitis was considered. The patient was initiated on antiviral therapy and, subsequently, oral corticosteroids. As the corticosteroids were tapered, the patient developed worsening lesions and vitreous inflammation. Pars plana vitrectomy (diagnostic and therapeutic) was performed and cytology sample revealed a highly eosinophilic infiltrate suggestive of parasitic infection. The real-time polymerase chain reaction was positive for . The diagnosis of ocular toxocariasis was made. This case highlights a highly unusual presentation where multiple retinal granulomas of ocular toxocariasis were observed in an immunocompetent male.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1080/09273948.2019.1597895DOI Listing
December 2020

An Autosomal Translocation 73,XY,t(12;20)(q11;q11) in an Infertile Male Llama () With Teratozoospermia.

Front Genet 2019 16;10:344. Epub 2019 Apr 16.

Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, United States.

Structural chromosome abnormalities, such as translocations and inversions occasionally occur in all livestock species and are typically associated with reproductive and developmental disorders. Curiously, only a few structural chromosome aberrations have been reported in camelids, and most involved sex chromosomes. This can be attributed to a high diploid number (2n = 74) and complex chromosome morphology, which makes unambiguous identification of camelid chromosomes difficult. Additionally, molecular tools for camelid cytogenetics are sparse and have become available only recently. Here we present a case report about an infertile male llama with teratozoospermia and abnormal chromosome number 2n = 73,XY. This llama carries an autosomal translocation of chromosomes 12 and 20, which is the likely cause of defective spermatogenesis and infertility in this individual. Our analysis underlines the power of molecular cytogenetics methods over conventional banding-based chromosome analysis for explicit identification of normal and aberrant chromosomes in camelid karyotypes. This is the first case of a translocation and the first autosomal aberration reported in any camelid species. It is proof of principle that, like in other mammalian species, structural chromosome abnormalities contribute to reproductive disorders in camelids.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fgene.2019.00344DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6476961PMC
April 2019

Author Correction: Layer-dependent quantum cooperation of electron and hole states in the anomalous semimetal WTe.

Nat Commun 2019 02 6;10(1):648. Epub 2019 Feb 6.

Department of Chemistry, Princeton University, Princeton, New Jersey, 08544, USA.

This Article contains an error in the spelling of the author A. Yazdani, which is incorrectly given as A. Yadzani. The error has not been fixed in the original PDF and HTML versions of the Article.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41467-019-08649-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6365586PMC
February 2019

Urban tinkering.

Sustain Sci 2018 6;13(6):1549-1564. Epub 2018 Aug 6.

19University of the Witwatersrand, Johannesburg, South Africa.

Cities are currently experiencing serious, multifaceted impacts from global environmental change, especially climate change, and the degree to which they will need to cope with and adapt to such challenges will continue to increase. A complex systems approach inspired by evolutionary theory can inform strategies for policies and interventions to deal with growing urban vulnerabilities. Such an approach would guide the design of new (and redesign of existing) urban structures, while promoting innovative integration of grey, green and blue infrastructure in service of environmental and health objectives. Moreover, it would contribute to more flexible, effective policies for urban management and the use of urban space. Four decades ago, in a seminal paper in , the French evolutionary biologist and philosopher Francois Jacob noted that evolution differs significantly in its characteristic modes of action from processes that are designed and engineered de novo (Jacob in Science 196(4295):1161-1166, 1977). He labeled the evolutionary process "tinkering", recognizing its foundation in the modification and molding of existing traits and forms, with occasional dramatic shifts in function in the context of changing conditions. This contrasts greatly with conventional engineering and design approaches that apply tailor-made materials and tools to achieve well-defined functions that are specified a priori. We here propose that urban tinkering is the application of evolutionary thinking to urban design, engineering, ecological restoration, management and governance. We define urban tinkering as:A mode of operation, encompassing policy, planning and management processes, that seeks to transform the use of existing and design of new urban systems in ways that diversify their functions, anticipate new uses and enhance adaptability, to better meet the social, economic and ecological needs of cities under conditions of deep uncertainty about the future.This approach has the potential to substantially complement and augment conventional urban development, replacing predictability, linearity and monofunctional design with anticipation of uncertainty and non-linearity and design for multiple, potentially shifting functions. Urban tinkering can function by promoting a diversity of small-scale urban experiments that, in aggregate, lead to large-scale often playful innovative solutions to the problems of sustainable development. Moreover, the tinkering approach is naturally suited to exploring multi-functional uses and approaches (e.g., bricolage) for new and existing urban structures and policies through collaborative engagement and analysis. It is thus well worth exploring as a means of delivering co-benefits for environment and human health and wellbeing. Indeed, urban tinkering has close ties to systems approaches, which often are recognized as critical to sustainable development. We believe this concept can help forge much-closer, much-needed ties among engineers, architects, evolutionary ecologists, health specialists, and numerous other urban stakeholders in developing innovative, widely beneficial solutions for society and contribute to successful implementation of SDG11 and the New Urban Agenda.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s11625-018-0611-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6267159PMC
August 2018

Horse Y chromosome assembly displays unique evolutionary features and putative stallion fertility genes.

Nat Commun 2018 07 27;9(1):2945. Epub 2018 Jul 27.

Texas A&M University, College Station, TX, 77843, USA.

Dynamic evolutionary processes and complex structure make the Y chromosome among the most diverse and least understood regions in mammalian genomes. Here, we present an annotated assembly of the male specific region of the horse Y chromosome (eMSY), representing the first comprehensive Y assembly in odd-toed ungulates. The eMSY comprises single-copy, equine specific multi-copy, PAR transposed, and novel ampliconic sequence classes. The eMSY gene density approaches that of autosomes with the highest number of retained X-Y gametologs recorded in eutherians, in addition to novel Y-born and transposed genes. Horse, donkey and mule testis RNAseq reveals several candidate genes for stallion fertility. A novel testis-expressed XY ampliconic sequence class, ETSTY7, is shared with the parasite Parascaris genome, providing evidence for eukaryotic horizontal transfer and inter-chromosomal mobility. Our study highlights the dynamic nature of the Y and provides a reference sequence for improved understanding of equine male development and fertility.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41467-018-05290-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6063916PMC
July 2018

Improvising livestock service in hilly regions through indigenous wisdom towards control of tick infestation: Institutional relationships.

Vet World 2018 May 24;11(5):687-692. Epub 2018 May 24.

National Innovation Foundation-India, Amarapur, Gandhinagar, Gujarat, India.

Aim: This study was conducted to demonstrate the acaricide efficacy of novel indigenous veterinary medication shared by an outstanding knowledge holder against naturally infested cattle and efforts in mainstreaming such wisdom.

Materials And Methods: An indigenous herbal medication in control of tick infestation was documented, and experimentation was held against naturally affected cattle. Eighteen clinically infested cattle population comprising 16 crossbred and 2 non-descript cattle were purposively selected. Majority of them were adult females, reported with a higher incidence of tick at Veterinary institution. The average pre-treatment tick count at 24 sites of observations among these animals was 18.91±2.04 (Mean [x̄]±standard error [SE]). The medication was topically applied once daily for 2 days and post-treatment observations were recorded for an experimental period of 14 days' duration.

Results: During 24-h post-treatment observation, the medication had shown 92.95% acaricidal property with clinically irrelevant rate of tick infestation of 1.33±0.39 (x̄ ±SE) was noticed before application of subsequent (second) dosage. This practice was found significantly effective at 5% level of significance (t=9.08) illustrating faster relief to livestock. Animals were treated with herbal medication as per dosage on the second day and no reinfestation was noticed up to 14 days of experimental observation.

Conclusion: The study strengthens the belief that indigenous herbal acaricide can facilitate quality livestock service at geographically distant locations. These medications can provide quicker relief, minimize tick resistance and are favorable to the environment.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.14202/vetworld.2018.687-692DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5993760PMC
May 2018

Novel drug delivery systems for ocular therapy: With special reference to liposomal ocular delivery.

Eur J Ophthalmol 2019 Jan 14;29(1):113-126. Epub 2018 May 14.

1 Department of Pharmaceutical Sciences, Dibrugarh University, Dibrugarh, India.

Delivery of drugs to eyes is a great challenge to researchers because of a number of barriers in the eye preventing the actual dose from reaching the site. A number of ophthalmic delivery systems have been developed in the past couple of years that are not only new but also safe and reliable and help to overcome all those barriers in the eye which are responsible for the very less bioavailability of drugs. In this review, we tried to focus on current research in ocular delivery of drug substances giving special emphasis to liposomal delivery system. A brief analysis of other novel ocular delivery systems, ocular physiology, and microbial sources of disease are also highlighted herein. We analyzed the various research findings for churning a general idea for novel ocular delivery system and its future use. The novel formulations may overcome the addressed problems of ophthalmic medication and comply with the quality assurance issues. The liposomal delivery is advantageous as they have the ability to entrap both hydrophobic and hydrophilic drugs and are suitable for delivery to both the anterior and posterior segment of the eye. Therefore, the use of this alternative approach is quite a necessity.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1177/1120672118769776DOI Listing
January 2019

Switching from Reactant to Substrate Engineering in the Selective Synthesis of Graphene Nanoribbons.

J Phys Chem Lett 2018 May 27;9(10):2510-2517. Epub 2018 Apr 27.

Donostia International Physics Center (DIPC) , 20018 San Sebastián , Spain.

The challenge of synthesizing graphene nanoribbons (GNRs) with atomic precision is currently being pursued along a one-way road, based on the synthesis of adequate molecular precursors that react in predefined ways through self-assembly processes. The synthetic options for GNR generation would multiply by adding a new direction to this readily successful approach, especially if both of them can be combined. We show here how GNR synthesis can be guided by an adequately nanotemplated substrate instead of by the traditionally designed reactants. The structural atomic precision, unachievable to date through top-down methods, is preserved by the self-assembly process. This new strategy's proof-of-concept compares experiments using 4,4''-dibromo-para-terphenyl as a molecular precursor on flat Au(111) and stepped Au(322) substrates. As opposed to the former, the periodic steps of the latter drive the selective synthesis of 6 atom-wide armchair GNRs, whose electronic properties have been further characterized in detail by scanning tunneling spectroscopy, angle resolved photoemission, and density functional theory calculations.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.jpclett.8b00796DOI Listing
May 2018

Update on the use of direct oral anticoagulants for the prevention and treatment of thromboembolism.

Future Cardiol 2018 01 11;14(1):89-99. Epub 2017 Dec 11.

Department of Pharmacy, Methodist University Hospital, 1265 Union Avenue, Memphis, TN 38104, USA.

Following publication of our review article 4 years ago, there has been an uptake in the use of nonvitamin K oral antagonists, also known as direct oral anticoagulants. The most recent Xa inhibitors to receive approval are edoxaban, which has been approved for use in both atrial fibrillation and venous thromboembolism prevention and betrixaban, which has been approved in the USA for extended thromboprophylaxis in the medically ill population. Additional analyses of certain types of atrial fibrillation patients have now become available. Ongoing prescriber vigilance is recommended as additional information continues to emerge with this class of medications. The purpose of this paper is to provide an update on the use of the direct oral anticoagulant agents for the prevention and treatment of thromboembolism.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.2217/fca-2017-0045DOI Listing
January 2018

Three-Dimensional Electronic Structure of the Type-II Weyl Semimetal WTe_{2}.

Phys Rev Lett 2017 Jul 14;119(2):026403. Epub 2017 Jul 14.

Istituto Officina dei Materiali (IOM)-CNR, Laboratorio TASC, in Area Science Park, S.S.14, Km 163.5, I-34149 Trieste, Italy.

By combining bulk sensitive soft-x-ray angular-resolved photoemission spectroscopy and first-principles calculations we explored the bulk electron states of WTe_{2}, a candidate type-II Weyl semimetal featuring a large nonsaturating magnetoresistance. Despite the layered geometry suggesting a two-dimensional electronic structure, we directly observe a three-dimensional electronic dispersion. We report a band dispersion in the reciprocal direction perpendicular to the layers, implying that electrons can also travel coherently when crossing from one layer to the other. The measured Fermi surface is characterized by two well-separated electron and hole pockets at either side of the Γ point, differently from previous more surface sensitive angle-resolved photoemission spectroscopy experiments that additionally found a pronounced quasiparticle weight at the zone center. Moreover, we observe a significant sensitivity of the bulk electronic structure of WTe_{2} around the Fermi level to electronic correlations and renormalizations due to self-energy effects, previously neglected in first-principles descriptions.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1103/PhysRevLett.119.026403DOI Listing
July 2017

Very efficient spin polarization analysis (VESPA): new exchange scattering-based setup for spin-resolved ARPES at APE-NFFA beamline at Elettra.

J Synchrotron Radiat 2017 07 13;24(Pt 4):750-756. Epub 2017 Jun 13.

CNR-IOM Laboratorio TASC, I-34149 Trieste, Italy.

Complete photoemission experiments, enabling measurement of the full quantum set of the photoelectron final state, are in high demand for studying materials and nanostructures whose properties are determined by strong electron and spin correlations. Here the implementation of the new spin polarimeter VESPA (Very Efficient Spin Polarization Analysis) at the APE-NFFA beamline at Elettra is reported, which is based on the exchange coupling between the photoelectron spin and a ferromagnetic surface in a reflectometry setup. The system was designed to be integrated with a dedicated Scienta-Omicron DA30 electron energy analyzer allowing for two simultaneous reflectometry measurements, along perpendicular axes, that, after magnetization switching of the two targets, allow the three-dimensional vectorial reconstruction of the spin polarization to be performed while operating the DA30 in high-resolution mode. VESPA represents the very first installation for spin-resolved ARPES (SPARPES) at the Elettra synchrotron in Trieste, and is being heavily exploited by SPARPES users since autumn 2015.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1107/S1600577517006907DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5493025PMC
July 2017

Giant Rashba effect at the topological surface of PrGe revealing antiferromagnetic spintronics.

Sci Rep 2017 06 23;7(1):4120. Epub 2017 Jun 23.

Synchrotrons Utilization Section, Raja Ramanna Centre for Advanced Technology, Indore, 452013, India.

Rashba spin-orbit splitting in the magnetic materials opens up a new perspective in the field of spintronics. Here, we report a giant Rashba spin-orbit splitting on the PrGe [010] surface in the paramagnetic phase with Rashba coefficient α  = 5 eVÅ. We find that α can be tuned in this system as a function of temperature at different magnetic phases. Rashba type spin polarized surface states originates due to the strong hybridization between Pr 4f states with the conduction electrons. Significant changes observed in the spin polarized surface states across the magnetic transitions are due to the competition between Dzyaloshinsky-Moriya interaction and exchange interaction present in this system. Presence of Dzyaloshinsky-Moriya interaction on the topological surface give rise to Saddle point singularity which leads to electron-like and hole-like Rashba spin split bands in the [Formula: see text] and [Formula: see text] directions, respectively. Supporting evidences of Dzyaloshinsky-Moriya interaction have been obtained as anisotropic magnetoresistance with respect to field direction and first-order type hysteresis in the X-ray diffraction measurements. A giant negative magnetoresistance of 43% in the antiferromagnetic phase and tunable Rashba parameter with temperature makes this material a suitable candidate for application in the antiferromagnetic spintronic devices.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-017-02401-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5482886PMC
June 2017

Image Diagnosis: Multivessel Percutaneous Coronary Intervention in Dextrocardia: Success with Usual Techniques in a Case of Mirror-Image Heart.

Perm J 2017 ;21:16-141

Cardiologist and the Program Director of the Interventional Cardiology Fellowship at the University of Tennessee Health Science Center in Memphis.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.7812/TPP/16-141DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5478588PMC
June 2018

Role of Oxygen Deposition Pressure in the Formation of Ti Defect States in TiO(001) Anatase Thin Films.

ACS Appl Mater Interfaces 2017 Jul 26;9(27):23099-23106. Epub 2017 Jun 26.

CNR-IOM, Laboratorio TASC , I-34149 Trieste, Italy.

We report the study of anatase TiO(001)-oriented thin films grown by pulsed laser deposition on LaAlO(001). A combination of in situ and ex situ methods has been used to address both the origin of the Ti-localized states and their relationship with the structural and electronic properties on the surface and the subsurface. Localized in-gap states are analyzed using resonant X-ray photoelectron spectroscopy and are related to the Ti electronic configuration, homogeneously distributed over the entire film thickness. We find that an increase in the oxygen pressure corresponds to an increase in Ti only in a well-defined range of deposition pressure; outside this range, Ti and the strength of the in-gap states are reduced.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acsami.7b03181DOI Listing
July 2017

In Situ complement activation and T-cell immunity in leprosy spectrum: An immunohistological study on leprosy lesional skin.

PLoS One 2017 15;12(5):e0177815. Epub 2017 May 15.

Department of Clinical Immunology, Colleges of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom.

Mycobacterium leprae (M. leprae) infection causes nerve damage and the condition worsens often during and long after treatment. Clearance of bacterial antigens including lipoarabinomannan (LAM) during and after treatment in leprosy patients is slow. We previously demonstrated that M. leprae LAM damages peripheral nerves by in situ generation of the membrane attack complex (MAC). Investigating the role of complement activation in skin lesions of leprosy patients might provide insight into the dynamics of in situ immune reactivity and the destructive pathology of M. leprae. In this study, we analyzed in skin lesions of leprosy patients, whether M. leprae antigen LAM deposition correlates with the deposition of complement activation products MAC and C3d on nerves and cells in the surrounding tissue. Skin biopsies of paucibacillary (n = 7), multibacillary leprosy patients (n = 7), and patients with erythema nodosum leprosum (ENL) (n = 6) or reversal reaction (RR) (n = 4) and controls (n = 5) were analyzed. The percentage of C3d, MAC and LAM deposition was significantly higher in the skin biopsies of multibacillary compared to paucibacillary patients (p = <0.05, p = <0.001 and p = <0.001 respectively), with a significant association between LAM and C3d or MAC in the skin biopsies of leprosy patients (r = 0.9578, p< 0.0001 and r = 0.8585, p<0.0001 respectively). In skin lesions of multibacillary patients, MAC deposition was found on axons and co-localizing with LAM. In skin lesions of paucibacillary patients, we found C3d positive T-cells in and surrounding granulomas, but hardly any MAC deposition. In addition, MAC immunoreactivity was increased in both ENL and RR skin lesions compared to non-reactional leprosy patients (p = <0.01 and p = <0.01 respectively). The present findings demonstrate that complement is deposited in skin lesions of leprosy patients, suggesting that inflammation driven by complement activation might contribute to nerve damage in the lesions of these patients. This should be regarded as an important factor in M. leprae nerve damage pathology.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0177815PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5432188PMC
September 2017

Genetic assessment of leech species from yak (Bos grunniens) in the tract of Northeast India.

Mitochondrial DNA A DNA Mapp Seq Anal 2018 01 14;29(1):73-81. Epub 2017 Mar 14.

a Department of Biotechnology , Assam University , Silchar , India.

Yak is an iconic symbol of Tibet and high altitudes of Northeast India. It is highly cherished for milk, meat, and skin. However, yaks suffer drastic change in milk production, weight loss, etc, when infested by parasites. Among them, infestation by leeches is a serious problem in the Himalayan belt of Northeast India. The parasite feeds on blood externally or from body orifices, like nasopharynx, oral, rectum, etc. But there has been limited data about the leech species infesting the yak in that region because of the difficulties in morphological identification due to plasticity of the body, changes in shape, and surface structure and thus, warrants for the molecular characterization of leech. In anticipation, this study would be influential in proper identification of leech species infesting yak track and also helpful in inventorying of leech species in Northeast India. Here, we investigated, through combined approach of molecular markers and morphological parameters for the identification of leech species infesting yak. The DNA sequences of COI barcode fragment, 18S and 28S rDNA, were analyzed for species identification. The generated sequences were subjected to similarity match in global database and analyzed further through Neighbour-Joining, K2P distance based as well as ML approach. Among the three markers, only COI was successful in delineating species whereas the 18S and 28S failed to delineate the species. Our study confirmed the presence of the species from genus Hirudinaria, Haemadipsa, Whitmania, and one species Myxobdella annandalae, which has not been previously reported from this region.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1080/24701394.2016.1238914DOI Listing
January 2018

Manipulating the Topological Interface by Molecular Adsorbates: Adsorption of Co-Phthalocyanine on Bi2Se3.

Nano Lett 2016 06 12;16(6):3409-14. Epub 2016 May 12.

Laboratoire de Physique des Solides, CNRS, Universitè Paris-Sud, Université Paris-Saclay , 91405 Orsay Cedex, France.

Topological insulators are a promising class of materials for applications in the field of spintronics. New perspectives in this field can arise from interfacing metal-organic molecules with the topological insulator spin-momentum locked surface states, which can be perturbed enhancing or suppressing spintronics-relevant properties such as spin coherence. Here we show results from an angle-resolved photemission spectroscopy (ARPES) and scanning tunnelling microscopy (STM) study of the prototypical cobalt phthalocyanine (CoPc)/Bi2Se3 interface. We demonstrate that that the hybrid interface can act on the topological protection of the surface and bury the Dirac cone below the first quintuple layer.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.nanolett.5b02635DOI Listing
June 2016

Factors Contributing to the Delay in Diagnosis and Continued Transmission of Leprosy in Brazil--An Explorative, Quantitative, Questionnaire Based Study.

PLoS Negl Trop Dis 2016 Mar 15;10(3):e0004542. Epub 2016 Mar 15.

Department of Clinical Immunology, School of Infection and Immunity, University of Birmingham, Birmingham, United Kingdom.

Background: Leprosy is a leading cause of preventable disability worldwide. Delay in diagnosis of patients augments the transmission of infection, and allows progression of disease and more severe disability. Delays in diagnosis greater than ten years have been reported in Brazil. To reduce this delay, it is important to identify factors that hinder patients from presenting to doctors, and those that delay doctors from diagnosing patients once they have presented. This study aimed to explore factors associated with the delayed diagnosis of leprosy in Brazil.

Methodology/ Principal Findings: This is an exploratory study using a self-constructed questionnaire delivered to patients attending three leprosy referral clinics across three states in Brazil. Data were analysed to determine associations between variables and the time taken for participants to present to the health-service, and between variables and the time taken for doctors to diagnose participants once they had presented. Participants who suspected they had leprosy but feared community isolation were 10 times more likely to wait longer before consulting a doctor for their symptoms (OR 10.37, 95% CI 2.18-49.45, p = 0.003). Participants who thought their symptoms were not serious had a threefold greater chance of waiting longer before consulting than those who did (OR 3.114, 95% CI 1.235-7.856, p = 0.016). Forty-two point six per cent of participants reported initially receiving a diagnosis besides leprosy. These had a three times greater chance of receiving a later diagnosis of leprosy compared to those not misdiagnosed or not given a diagnosis (OR 2.867, 95% CI 1.288-6.384, p = 0.010).

Conclusions/ Significance: This study implies a need for patient education regarding leprosy symptoms and the reduction of stigma to encourage patients to present. The high rate of misdiagnosis reported suggests a need to increase clinician suspicion of leprosy. Further education regarding disease symptoms in medical school curriculums may be advisable.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1371/journal.pntd.0004542DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4792453PMC
March 2016
-->