27 research outputs found

    On `orbital' and `spin' angular momentum of light in classical and quantum theories -- a general framework

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    We develop a general framework to analyze the two important and much discussed questions concerning (a) `orbital' and `spin' angular momentum carried by light and (b) the paraxial approximation of the free Maxwell system both in the classical as well as quantum domains. After formulating the classical free Maxwell system in the transverse gauge in terms of complex analytical signals we derive expressions for the constants of motion associated with its Poincar\'{e} symmetry. In particular, we show that the constant of motion corresponding to the total angular momentum J{\bf J} naturally splits into an `orbital' part L{\bf L} and a `spin' part S{\bf S} each of which is a constant of motion in its own right. We then proceed to discuss quantization of the free Maxwell system and construct the operators generating the Poincar\'{e} group in the quantum context and analyze their algebraic properties and find that while the quantum counterparts L^\hat{{\bf L}} and S^\hat{{\bf S}} of L{\bf L} and S{\bf S} go over into bona fide observables, they fail to satisfy the angular momentum algebra precluding the possibility of their interpretation as `orbital' and `spin' operators at the classical level. On the other hand J^=L^+S^\hat{{\bf J}}=\hat{{\bf L}}+ \hat{{\bf S}} does satisfy the angular momentum algebra and together with S^\hat{{\bf S}} generates the group E(3)E(3). We then present an analysis of single photon states, paraxial quantization both in the scalar as well as vector cases, single photon states in the paraxial regime. All along a close connection is maintained with the Hilbert space M\mathcal{M} that arises in the classical context thereby providing a bridge between classical and quantum descriptions of radiation fields.Comment: Revtex 4-1 16 page

    The development of quantum, mechanics: a story of people, places and philosophies

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    A historical account of the development of quantum mechanics,and the roles played by many outstanding physicists, theirviews and philosophical attitudes is presented. Ingenious andpath-breaking experiments that helped this development alongare highlighted. Ideas and notions that initially arose in thecourse of discussions on foundations of quantum mechanicsand later paved the way for the emergence of the fieldof Quantum Information Science and Technology are brieflytouched upon

    Symmetries and conservation laws in classical and quantum mechanics. 1. Classical mechanics

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    We describe the connection between continuous symmetries and conservation laws in classical mechanics. This is done at successively more sophisticated levels, bringing out important features at each level: the Newtonian, the Euler-Lagrange, and the Hamiltonian phase-space forms of mechanics. The role of the Action Principle is emphasised, and many examples are given

    2-Amino-5-sulfanil-1,3,4-tidiazoli: Nova serija selektivnih inhibitora ciklooksigenaze-2

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    A new series of cyclooxygenase-2 inhibitors with 2-amino-5-sulfanyl-1,3,4-thiadiazole as the central scaffold unit has been synthesized. The newly synthesized compounds were characterized by analytical and spectral methods. Compounds were screened for cyclooxygenase inhibitory activity by colorimetric COX (ovine) inhibitor screening assay, anti-inflammatory activity by the carrageenean induced rat paw oedema test and analgesic activity by the tail flick method. Some compounds exhibited significant biological activity.Sintetizirana je nova serija inhibitora ciklooksigenaze-2 s 2-amino-5-sulfanil-1,3,4-tiadiazolom. Novi spojevi karakterizirani su uobičajenim analitičkim i spektroskopskim metodama. Sintetiziranim spojevima ispitana je sposobnost inhibicije ciklooksigenaze kolorimetrijskim COX testom (goveđi COX), protuupalno djelovanje na edem šape induciran karageninom i analgetsko djelovanje metodom pomicanja repa. Neki spojevi su pokazali značajno biološko djelovanje

    The ISWI Chromatin Remodeler Organizes the hsrω ncRNA–Containing Omega Speckle Nuclear Compartments

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    The complexity in composition and function of the eukaryotic nucleus is achieved through its organization in specialized nuclear compartments. The Drosophila chromatin remodeling ATPase ISWI plays evolutionarily conserved roles in chromatin organization. Interestingly, ISWI genetically interacts with the hsrω gene, encoding multiple non-coding RNAs (ncRNA) essential, among other functions, for the assembly and organization of the omega speckles. The nucleoplasmic omega speckles play important functions in RNA metabolism, in normal and stressed cells, by regulating availability of hnRNPs and some other RNA processing proteins. Chromatin remodelers, as well as nuclear speckles and their associated ncRNAs, are emerging as important components of gene regulatory networks, although their functional connections have remained poorly defined. Here we provide multiple lines of evidence showing that the hsrω ncRNA interacts in vivo and in vitro with ISWI, regulating its ATPase activity. Remarkably, we found that the organization of nucleoplasmic omega speckles depends on ISWI function. Our findings highlight a novel role for chromatin remodelers in organization of nucleoplasmic compartments, providing the first example of interaction between an ATP-dependent chromatin remodeler and a large ncRNA

    Effectiveness and cost-effectiveness of a Yoga-based Cardiac Rehabilitation (Yoga-CaRe) program following acute myocardial infarction: study rationale and design of a multi-centre randomized controlled trial

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    © 2019 Background: Cardiac rehabilitation (CR) is a standard treatment for secondary prevention of acute myocardial infarction (AMI) in high income countries (HICs), but it is inaccessible to most patients in India due to high costs and skills required for multidisciplinary CR teams. We developed a low-cost and scalable CR program based on culturally-acceptable practice of yoga (Yoga-CaRe). In this paper, we report the rationale and design for evaluation of its effectiveness and cost-effectiveness. Methods: This is a multi-center, single-blind, two-arm parallel-group randomized controlled trial across 22 cardiac care hospitals in India. Four thousand patients aged 18–80 years with AMI will be recruited and randomized 1:1 to receive Yoga-CaRe program (13 sessions supervised by an instructor and encouragement to self-practice daily) or enhanced standard care (3 sessions of health education) delivered over a period of three months. Participants will be followed 3-monthly till the end of the trial. The co-primary outcomes are a) time to occurrence of first cardiovascular event (composite of all-cause mortality, non-fatal myocardial infarction, non-fatal stroke and emergency cardiovascular hospitalization), and b) quality of life (Euro-QoL-5L) at 12 weeks. Secondary outcomes include need for revascularization procedures, return to pre-infarct activities, tobacco cessation, medication adherence, and cost-effectiveness of the intervention. Conclusion: This trial will alone contribute >20% participants to existing meta-analyses of randomized trials of CR worldwide. If Yoga-CaRe is found to be effective, it has the potential to save millions of lives and transform care of AMI patients in India and other low and middle income country settings

    Ketorolak-dekstran konjugati: sinteza, in vitro i in vivo vrednovanje

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    Ketorolac is a non-steroidal anti-inflammatory drug. Dextran conjugates of ketorolac (KD) were synthesized and characterized to improve ketorolac aqueous solubility and reduce gastrointestinal side effects. An N-acylimidazole derivative of ketorolac (KAI) was condensed with a model carrier polymer, dextran of different molecular masses (40000, 60000, 110000 and 200000). IR spectral data confirmed formation of ester bonding. Ketorolac contents were evaluated by UV-spectrophotometric analysis. The molecular mass was determined by measuring viscosity using the Mark-Howink-Sakurada equation. In vitro hydrolysis studies were performed in aqueous buffers (pH 1.2, 7.4, 9) and in 80% (V/V) human plasma (pH 7.4). At pH 9, a higher rate of ketorolac release from KD was observed as compared to aqueous buffer of pH 7.4 and 80% human plasma (pH 7.4), following first-order kinetics. In vivo biological screening in mice and rats indicated that conjugates retained analgesic and anti-inflammatory activities with significantly reduced ulcerogenicity compared to the parent drug.U radu je opisana sinteza konjugata dektrana i protuupalnog lijeka ketorolaka (KD). Konjugati su pripravljeni da bi se povećala topljivost ketorolaka u vodi i smanjila njegova nusdjelovanja u gastrointestinanom traktu. Ketorak je prvo preveden u N-acilimidazolni derivat (KAI) koji je kondenziran s polimernim nosačem, dekstranom različitih molekulskih masa (40000, 60000, 110000 i 200000). IR-spektri potvrdili su nastajanje esterske veze. Udio ketorolaka u konjugatu određen je UV-spektrofotometrijskom analizom. Molekulske mase određene su mjerenjem viskoznosti koristeći Mark-Howink-Sakurada jednadžbu. Hidroliza in vitro praćena je u puferskim otopinama (pH 1,2, 7,4 i 9) i u 80% V/V humanoj plazmi (pH 7,4). Pri pH 9 primjećeno je značajno brže oslobađanje ketorolaka iz KD nego u puferskoj otopini pH 7,4 i krvnoj plazmi. Oslobađanje je prati kinetiku prvog reda. In vivo biološka ispitivanja na miševima i štakorima ukazuju da konjugati imaju analgetsko i protuupalno djelovanje, a značajno smanjeno ulcerogeno djelovanje

    Genome-wide identification and characterization of Puccinia striiformis-responsive lncRNAs in Triticum aestivum

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    Wheat stripe rust (yellow rust) caused by Puccinia striiformis f. sp. tritici (Pst) is a serious biotic stress factor limiting wheat production worldwide. Emerging evidence demonstrates that long non-coding RNAs (lncRNAs) participate in various developmental processes in plants via post-transcription regulation. In this study, RNA sequencing (RNA-seq) was performed on a pair of near-isogenic lines—rust resistance line FLW29 and rust susceptible line PBW343—which differed only in the rust susceptibility trait. A total of 6,807 lncRNA transcripts were identified using bioinformatics analyses, among which 10 lncRNAs were found to be differentially expressed between resistance and susceptible lines. In order to find the target genes of the identified lncRNAs, their interactions with wheat microRNA (miRNAs) were predicted. A total of 199 lncRNAs showed interactions with 65 miRNAs, which further target 757 distinct mRNA transcripts. Moreover, detailed functional annotations of the target genes were used to identify the candidate genes, pathways, domains, families, and transcription factors that may be related to stripe rust resistance response in wheat plants. The NAC domain protein, disease resistance proteins RPP13 and RPM1, At1g58400, monodehydroascorbate reductase, NBS-LRR-like protein, rust resistance kinase Lr10-like, LRR receptor, serine/threonine-protein kinase, and cysteine proteinase are among the identified targets that are crucial for wheat stripe rust resistance. Semiquantitative PCR analysis of some of the differentially expressed lncRNAs revealed variations in expression profiles of two lncRNAs between the Pst-resistant and Pst-susceptible genotypes at least under one condition. Additionally, simple sequence repeats (SSRs) were also identified from wheat lncRNA sequences, which may be very useful for conducting targeted gene mapping studies of stripe rust resistance in wheat. These findings improved our understanding of the molecular mechanism responsible for the stripe rust disease that can be further utilized to develop wheat varieties with durable resistance to this disease

    Detection of autoantibodies against reactive oxygen species modified glutamic acid decarboxylase-65 in type 1 diabetes associated complications

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    <p>Abstract</p> <p>Background</p> <p>Autoantibodies against glutamate decarboxylase-65 (GAD<sub>65</sub>Abs) are thought to be a major immunological tool involved in pathogenic autoimmunity development in various diseases. GAD<sub>65</sub>Abs are a sensitive and specific marker for type 1 diabetes (T1D). These autoantibodies can also be found in 6-10% of patients classified with type 2 diabetes (T2D), as well as in 1-2% of the healthy population. The latter individuals are at low risk of developing T1D because the prevalence rate of GAD<sub>65</sub>Abs is only about 0.3%. It has, therefore, been suggested that the antibody binding to GAD<sub>65 </sub>in these three different GAD<sub>65</sub>Ab-positive phenotypes differ with respect to epitope specificity. The specificity of reactive oxygen species modified GAD<sub>65 </sub>(ROS-GAD<sub>65</sub>) is already well established in the T1D. However, its association in secondary complications of T1D has not yet been ascertained. Hence this study focuses on identification of autoantibodies against ROS-GAD<sub>65 </sub>(ROS-GAD<sub>65</sub>Abs) and quantitative assays in T1D associated complications.</p> <p>Results</p> <p>From the cohort of samples, serum autoantibodies from T1D retinopathic and nephropathic patients showed high recognition of ROS-GAD<sub>65 </sub>as compared to native GAD<sub>65 </sub>(N-GAD<sub>65</sub>). Uncomplicated T1D subjects also exhibited reactivity towards ROS-GAD<sub>65</sub>. However, this was found to be less as compared to the binding recorded from complicated subjects. These results were further proven by competitive ELISA estimations. The apparent association constants (AAC) indicate greater affinity of IgG from retinopathic T1D patients (1.90 × 10<sup>-6 </sup>M) followed by nephropathic (1.81 × 10<sup>-6 </sup>M) and uncomplicated (3.11 × 10<sup>-7 </sup>M) T1D patients for ROS-GAD<sub>65 </sub>compared to N-GAD<sub>65</sub>.</p> <p>Conclusion</p> <p>Increased oxidative stress and blood glucose levels with extended duration of disease in complicated T1D could be responsible for the gradual formation and/or exposing cryptic epitopes on GAD<sub>65 </sub>that induce increased production of ROS-GAD<sub>65</sub>Abs. Hence regulation of ROS-GAD<sub>65</sub>Abs could offer novel tools for analysing and possibly treating T1D complications.</p

    Development of a Yoga-Based Cardiac Rehabilitation (Yoga-CaRe) Programme for Secondary Prevention of Myocardial Infarction

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    Cardiac rehabilitation (CR) after myocardial infarction is highly effective. It is unavailable in public hospitals in India due to limited resources. Our objective was to develop a scalable model of CR for India based on yoga, which could also appeal to some groups with low uptake of CR (e.g., ethnic minorities, women, and older people) globally. The intervention was developed using a structured process. A literature review and consultations with yoga experts, CR experts, and postmyocardial infarction patients were conducted to systematically identify and shortlist appropriate yoga exercises and postures, breathing exercises, meditation and relaxation practices, and lifestyle changes, which were incorporated into a conventional CR framework. The draft intervention was further refined based on the feedback from an internal stakeholder group and an external panel of international experts, before being piloted with yoga instructors and patients with myocardial infarction. A four-phase yoga-based CR (Yoga-CaRe) programme was developed for delivery by a single yoga instructor with basic training. The programme consists of a total of 13 instructor-led sessions (2 individual and 11 group) over a 3-month period. Group sessions include guided practice of yoga exercises and postures, breathing exercises, and meditation and relaxation practices, and support for the lifestyle change and coping through a moderated discussion. Patients are encouraged to self-practice daily at home and continue long-term with the help of a booklet and digital video disc (DVD). Family members/carers are encouraged to join throughout. In conclusion, a novel yoga-based CR programme has been developed, which promises to provide a scalable CR solution for India and an alternative choice for CR globally. It is currently being evaluated in a large multicentre randomised controlled trial across India
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