Browsing by Author "S. Prasad"

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A comparative study of dispersion relation of em waves in ternary one-dimensional plasma photonic crystals having two different structures
(2011) S. Prasad; Vivek Singh; A.K. Singh
In this paper, a rigorous theoretical analysis has been made to study the dispersion relation of EM waves in periodic ternary one-dimensional photonic crystal having two different structures. In one case we have chosen glass-plasma and ZnS in one unit cell and in other case we have considered glass-plasma and MgF2 in one unit cell. Using Kronig-Penney model the dispersion relation for proposed structures has been obtained and numerical results are presented in the form of dispersion curves. The dependence of photonic band gap (PBG) characteristics on plasma frequency, plasma width and the width of dielectric media are discussed in the light of frequency gap and cutoffs of binary one-dimensional plasma photonic crystal. An attempt has been made to show how the PBG characteristic of a particular structure changes when the dielectric materials of its unit cell is changed by the other dielectric material. It is found that the structure having glass-plasma-ZnS in unit cell is more useful for broad band filtering and other plasma functioning devices compared to the structure having glass-plasma-MgF2 in one unit cell. © 2010 Elsevier GmbH. All rights reserved.
A comparative study of the reflectivity of binary and ternary one-dimensional plasma photonic crystals for obliquely incident electromagnetic wave
(2013) S. Prasad; V. Singh; A.K. Singh
In present paper the reflectivity of binary and ternary one-dimensional plasma photonic crystals for obliquely incident electromagnetic waves are studied. The reflectivity is derived using transfer matrix method and solving Maxwell's equations by employing the continuity conditions on the electric fields and its derivatives. Our analysis shows that the perfect reflection bands get enhanced in the ternary 1D-PPCs com- pared to the binary 1D-PPCs. Also the ternary 1D-PPCs provide an additional degree of freedom to control the perfect reflection bands. © Pleiades Publishing, Ltd., 2013.
A Special Extract of Bacopa monnieri (CDRI-08) Restores Learning and Memory by Upregulating Expression of the NMDA Receptor Subunit GluN2B in the Brain of Scopolamine-Induced Amnesic Mice
(Hindawi Limited, 2015) Rakesh Rai; Hemant K. Singh; S. Prasad
In the present communication, we have investigated effects of the CDRI-08, a well characterized extract of Bacopa monnieri, on expression of the GluN2B subunit of NMDAR in various brain regions of the scopolamine-induced amnesic mice. Our behavioral data reveal that scopolamine-treated amnesic mice exhibit significant decline in the spatial memory compared to the normal control mice. Our RT-PCR and immunoblotting data revealed that the scopolamine treatment resulted in a significant downregulation of the NMDAR GluN2B subunit expression in prefrontal cortex and hippocampus. Our enzyme assay data revealed that scopolamine caused a significant increase in the acetylcholinesterase activity in both the brain regions. Further, oral administration of the CDRI-08 to scopolamine-treated amnesic mice restored the spatial memory which was found to be associated with significant upregulation of the GluN2B subunit expression and decline in the acetylcholinesterase activity in prefrontal cortex as well as hippocampus towards their levels in the normal control mice. Our study provides the evidence for the mechanism underlying role of the Bacopa monnieri extract (CDRI-08) in restoring spatial memory in amnesic mice, which may have therapeutic implications. © 2015 Rakesh Rai et al.
A Special Extract of Bacopa monnieri (CDRI-08)-Restored Memory in CoCl2-Hypoxia Mimetic Mice Is Associated with Upregulation of Fmr-1 Gene Expression in Hippocampus
(Hindawi Limited, 2015) Anupama Rani; S. Prasad
Fragile X mental retardation protein (FMRP) is a neuronal translational repressor and has been implicated in learning, memory, and cognition. However, the role of Bacopa monnieri extract (CDRI-08) in enhancing cognitive abilities in hypoxia-induced memory impairment via Fmr-1 gene expression is not known. Here, we have studied effects of CDRI-08 on the expression of Fmr-1 gene in the hippocampus of well validated cobalt chloride (CoCl2)-induced hypoxia mimetic mice and analyzed the data with alterations in spatial memory. Results obtained from Morris water maze test suggest that CoCl2 treatment causes severe loss of spatial memory and CDRI-08 is capable of reversing it towards that in the normal control mice. Our semiquantitative RT-PCR, Western blot, and immunofluorescence microscopic data reveal that CoCl2-induced hypoxia significantly upregulates the expression of Hif-1α and downregulates the Fmr-1 expression in the hippocampus, respectively. Further, CDRI-08 administration reverses the memory loss and this is correlated with significant downregulation of Hif-1α and upregulation of Fmr-1 expression. Our data are novel and may provide mechanisms of hypoxia-induced impairments in the spatial memory and action of CDRI-08 in the recovery of hypoxia led memory impairment involving Fmr-1 gene encoded protein called FMRP. © 2015 Anupama Rani and S. Prasad.
ADP-ribosylation of HMG proteins and its modulation by different effectors in the liver of aging rats
(1990) M.K. Thakur; S. Prasad
The in vitro ADP-ribosylation of high mobility group (HMG) non-histone proteins and its modulation by spermine, butyrate, dexamethasone and 3-aminobenzamide were studied in the liver of young (14 weeks) and old (113 weeks) male rats. ADP-ribosylation of HMG 1 was similar in both ages, whereas that of HMG 2 and 14 decreased but HMG 17 increased in the old. HMG 1 was ADP-ribosylated to a greater extent in young but to a lower level in the old by different effectors except spermine which showed no influence in old age. ADP-ribosylation of HMG 2 was stimulated by spermine, butyrate and dexamethasone in old but only by spermine in young rats. Other effectors decreased the ADP-ribosylation of HMG 2 in young. The ADP-ribosylation of HMG 14 was stimulated by spermine in the old but that of HMG 17 was reduced by butyrate in young and by spermine in the old. Dexamethasone decreased the ADP-ribosylation of both HMG 14 and 17 in young, whereas this showed no change in old age. Aminobenzamide inhibited ADP-ribosylation of only HMG 2 in young but all HMGs except HMG 2 in the old. Such alteration in the ADP-ribosylation of HMG proteins may affect various cellular and nuclear functions of rat liver during aging. © 1990.
Age- and sex-dependent differential interaction of nuclear trans-acting factors with Fmr-1 promoter in mice brain
(2008) S. Prasad; Kanchan Singh
We have investigated relation between interaction of the trans-acting factors with Fmr-1 promoter and expression of FMRP isoforms in intact mouse brain as a function of age and sex. Our EMSA data reveal that among the three complexes formed with 136 bp Fmr-1 promoter fragment, the level of complex C1 significantly increases in adult brain but decreases in old brain in comparison to that in young. The level of total FMRP significantly decreases from young to old in the brain of both the sexes, however, among the three isoforms, expression of the 80-kDa isoform significantly decreases in the brain of both the sexes where as the level of 70 kDa isoform decreases in females during aging. The present finding on relation between age- and sex-dependent interaction of trans-acting factors and expression of FMRP isoforms is novel and may be relevant for regulation of Fmr-1 gene in brain function during aging. © 2007 Springer Science+Business Media, LLC.
Age- and sex-related analysis of methylation of 5′-upstream sequences of Fmr-1 gene in mouse brain and modulation by sex steroid hormones
(2008) Kanchan Singh; S. Prasad
Fmr-1 gene is implicated in synaptic plasticity and thereby learning, memory and cognition, and methylation of Fmr-1 gene is necessary for memory development that is an age-dependent phenomenon. Aging in general has been reported to affect methylation of gene, however, nothing is known on the age dependent variation in methylation of Fmr-1 gene. Using the brain tissues from male and female mice of various age groups and sex steroid hormones (testosterone or 17β-estradiol) as modulators, restriction enzymes Hpa II and Msp I and Southern blotting technique, we studied methylation of 5′-upstream sequences of Fmr-1 gene. Our data reveal that the methylation of the 5′-upstream sequences that include CpG islands in promoter and 5′-untraslated region (5′-UTR) gradually increases due to advancing age in both the sexes. 17β-estradiol lowers the methylation significantly in the brain of mouse of both male and female mouse in age-dependent manner where as testosterone does not affect it appreciably. The alteration in the methylation may be attributed to altered DNA methyl transferase (DNMT) activity as the age increases from young to old, and the 17β-estradiol may down regulate the DNMT activity in both the age and sex groups whereas the testosterone may not have similar effect on DNMT. Down regulation of methylation of Fmr-1 CpG island and/or 5′-UTR by 17β-estradiol might lead to derepression of Fmr-1 gene especially in old age. This finding on Fmr-1 methylation is novel and it might have implications in understanding fragile X related disorders and age-dependent alteration in LTP and LTD. © Springer Science+Business Media B.V. 2008.
Age-Dependent Alterations in the Interactions of NF-κB and N-myc with GLT-1/EAAT2 Promoter in the Pericontusional Cortex of Mice Subjected to Traumatic Brain Injury
(Humana Press Inc., 2016) Rajaneesh K. Gupta; S. Prasad
Traumatic brain injury (TBI) is one of the major risk factors of dementia, aging, and cognitive impairments, etc. We have previously reported that expression of the astrocytic glutamate transporter GLT-1/EAAT2 is downregulated in the pericontusional cortex of adult and old mice in post-TBI time-dependent manner, and the process of decline starts before in old than in adult TBI mice. However, relationship between age- and TBI-dependent alterations in GLT-1/EAAT2 expression and interactions of transcription factors NF-κB and N-myc with their cognate GLT-1/EAAT2 promoter sequences, an important step of its transcriptional control, is not known. To understand this, we developed TBI mouse model by modified chronic head injury (CHI) method, analyzed expression of GFAP, TNF-α, and AQP4 by RT-PCR for its validation, and analyzed interactions of NF-κB and N-myc with GLT-1/EAAT2 promoter sequences by electrophoretic mobility shift assay (EMSA). Our EMSA data revealed that interactions of NF-κB and N-myc with GLT-1/EAAT2 promoter sequences was significantly elevated in the ipsi-lateral cortex of both adult and old TBI mice in post-TBI time-dependent manner; however, these interactions started immediately in the old compared to that in adult TBI mice, which could be attributed to our previously reported age- and post-TBI time-dependent differential expression of GLT-1/EAAT2 in the pericontusional cortex. © 2015, Springer Science+Business Media New York.
Age-dependent effects of sodium butyrate and hydrocortisone on acetylation of high mobility group proteins of rat liver.
(1988) S. Prasad; M.K. Thakur
The in vitro acetylation of high mobility group (HMG) proteins and its modulation by sodium butyrate and hydrocortisone have been studied using liver slices of young (13-) and old (114-week-old) rats. Acetylation of total HMG proteins was significantly higher in young than old rats. HMG 1, in particular, showed greater acetylation than others. Whereas acetylation of HMG 1 and 2 decreased drastically, that of HMG 14 and 17 increased in old age. In young rats, sodium butyrate and hydrocortisone stimulated acetylation of HMG 14 and 17, and decreased that of HMG 2. Butyrate had no effect on HMG 1, but hydrocortisone decreased it. In old rats, butyrate and hydrocortisone decreased acetylation of all HMGs, except HMG 17, which was stimulated to a slight extent by butyrate.
Age-specific methylation of high-mobility-group proteins of the rat liver and its modulation by spermine and sodium butyrate
(1989) M.K. Thakur; S. Prasad
Liver slices from young (20 weeks) and old (117 weeks) rat were incubated with [methyl-14C]methionine in the absence or presence of spermine or sodium butyrate. The high-mobility-group (HMG) non-histone proteins were extracted from the liver with perchloric acid and separated by acid-urea polyacrylamide slab gel electrophoressi. Methylation of HMG proteins decreased drastically in old rats. Whereas spermine inhibited the methylation of total HMG proteins in young rats, it had no effect in old age. On the contrary, sodium butyrate did not change the incorporation of methyl groups into total HMG proteins of young rats, but inhibited that of old rats. Particularly, the incorporation of [14C]methyl groups into HMG 2 was enhanced but into other HMGs it was reduced by both effectors in young and old age. Such discrepancies in the methylation of HMG proteins and their differential modulation by spermine and butyrate might affect the higher-order organization of chromatin and consequential destabilize the expression of genes during aging. © 1989.
Aging: The current perspectives
(Nova Science Publishers, Inc., 2011) S. Prasad; Ravi S. Pandey
Aging is a universal phenomenon that leads to decline in the efficiency of various body functions after an organism attains adulthood. This process is highly conserved over all the species from protozoan to mammals. After the attainment of reproductive maturity, especially in mammals, a consistent decline in the function of vital organs of the body is well documented. Some diseases such as diabetes mellitus, cardiovascular diseases, Alzheimer's diseases, Parkinsonism, lewy body dementia, osteoporosis etc mark the onset of aging. Enormous amount of literatures have accumulated giving emphasis on the age-related alterations in the function of individual organs. Researchers have long been looking for the answer to basic cause of aging. Though several theories have been proposed to explain this process, none of them has yet got unanimous acceptance. Development of advanced molecular genetic techniques has contributed significantly in the understanding of the basic cellular processes that are altered during aging. However, the answer to the basic question, what causes aging, still remains an enigma. The core aim of the present article is to summarize and discuss the developments in the last two decades on biological aspect of aging concentrating mainly on brain aging and outlining the modern interventional relevance for the treatment of age related neurodegenerative diseases. © 2011 by Nova Science Publishers, Inc. All rights reserved.
Alterations in hippocampal oxidative stress, expression of AMPA receptor GluR2 subunit and associated spatial memory loss by Bacopa monnieri extract (CDRI-08) in streptozotocin-induced diabetes mellitus type 2 mice
(Public Library of Science, 2015) Surya P. Pandey; Hemant K. Singh; S. Prasad
Bacopa monnieri extract has been implicated in the recovery of memory impairments due to various neurological disorders in animal models and humans. However, the precise molecular mechanism of the role of CDRI-08, a well characterized fraction of Bacopa monnieri extract, in recovery of the diabetes mellitus-induced memory impairments is not known. Here, we demonstrate that DM2 mice treated orally with lower dose of CDRI-08 (50- or 100 mg/kg BW) is able to significantly enhance spatial memory in STZ-DM2 mice and this is correlated with a significant decline in oxidative stress and up regulation of the AMPA receptor GluR2 subunit gene expression in the hippocampus. Treatment of DM2 mice with its higher dose (150 mg/kg BW or above) shows anti-diabetic effect in addition to its ability to recover the spatial memory impairment by reversing the DM2-induced elevated oxidative stress and decreased GluR2 subunit expression near to their values in normal and CDRI-08 treated control mice. Our results provide evidences towards molecular basis of the memory enhancing and anti diabetic role of the Bacopa monnieri extract in STZ-induced DM2 mice, which may have therapeutic implications. Copyright: © 2015 Pandey et al.
Alterations in the Sp1 binding and Fmr-1 gene expression in the cortex of the brain during maturation and aging of mouse
(Kluwer Academic Publishers, 2014) Pankaj Gaur; S. Prasad
Fragile X mental retardation protein (FMRP) has been implicated in learning, memory and cognition, therefore, information on alterations in FMRP expression during maturation and aging may provide a clue towards understanding mechanisms of age-dependent cognitive changes in the brain. In the present paper, we have studied Fmr-1 gene expression and its correlation with interaction of a tans-acting factor Sp1with Fmr-1 promoter in the cerebral cortex of female mice at post natal period during maturation and aging. Our data reveal that level of Fmr-1 transcript in the cerebral cortex is significantly up regulated at day 7 after birth compared to day 0 (the day of birth) and is gradually down regulated from day 15 onward to old age. The pattern of Fmr-1 transcript levels corresponds with the level of FMRP, however, its level is significantly up regulated in old age compared to adult mice. Our EMSA data revealed the formation of a single complex as a result of binding of Sp1with Fmr-1 promoter sequence. Its intensity gradually decreased from the day 0 (day of birth) till day 15, remained unaltered in young, significantly decreased in adult and significantly increased in old age. Our data suggests that age-dependent alteration in the Fmr-1 gene expression is associated with Sp1 interaction with Fmr-1 promoter which in turn might be related with cognitive development during brain maturation and aging. © 2014, Springer Science+Business Media Dordrecht.
Amino‐derivatives of Vanadium Tetrachloride with Secondary and Tertiary Amines
(1965) S. Prasad; R.C. Srivastava
Amino‐derivatives of vanadium(IV) are prepared by the action of vanadium(IV) chloride with some secondary and tertiary amines, their properties studied and probable structures discussed. Analytical results reveal that two molecules of the amine are attached to one mole of vanadium(IV) chloride. The study of the amino‐derivatives of vanadium(IV) chloride has been continued using the same methods of investigation as reported in Part I1). These compounds are very similar to the compounds formed with primary amines given in the previous work. The present work deals with the study of the preparation and properties of the compounds of vanadium tetrachloride with secondary and tertiary amines in non‐aqueous media. Copyright © 1965 Verlag GmbH & Co. KGaA, Weinheim
Analysis of age-associated alteration in the synthesis of HMG nonhistone proteins of the rat liver
(Kluwer Academic Publishers, 1991) M.K. Thakur; S. Prasad
HMG proteins were extracted with 5% PCA or 0.35 M NaCl from whole tissue, nuclei or chromatin of the liver of young (19 weeks) and old (118 weeks) male rats. They were resolved on acetic acid-urea polyacrylamide gel. The electrophoretic patterns of the major HMG proteins 1, 2, 14 and 17 of both ages are similar. The in vitro synthesis of HMG 1 and 2 decreases, but that of HMG 14 and 17 increases considerably in the liver of old rats. The synthesis of different HMG proteins is modulated differentially by spermine, butyrate, dexamethasone and 3-aminobenzamide in the liver of young and old rats. These findings suggest that HMG proteins contribute to alterations in the organization of chromatin and expression of genes during aging. © 1991 Kluwer Academic Publishers.
ATHENA detector proposal - a totally hermetic electron nucleus apparatus proposed for IP6 at the Electron-Ion Collider
(Institute of Physics, 2022) J. Adam; L. Adamczyk; N. Agrawal; C. Aidala; W. Akers; M. Alekseev; M.M. Allen; F. Ameli; A. Angerami; P. Antonioli; N.J. Apadula; A. Aprahamian; W. Armstrong; M. Arratia; J.R. Arrington; A. Asaturyan; E.C. Aschenauer; K. Augsten; S. Aune; K. Bailey; C. Baldanza; M. Bansal; F. Barbosa; L. Barion; K. Barish; M. Battaglieri; A. Bazilevsky; N.K. Behera; V. Berdnikov; J. Bernauer; C. Berriaud; A. Bhasin; D.S. Bhattacharya; J. Bielcik; J. Bielcikova; C. Bissolotti; W. Boeglin; M. Bondì; M. Borri; F. Bossù; F. Bouyjou; J.D. Brandenburg; A. Bressan; M. Brooks; S.L. Bültmann; D. Byer; H. Caines; M. Calderon De La Barca Sanchez; V. Calvelli; A. Camsonne; L. Cappelli; M. Capua; M. Castro; D. Cavazza; D. Cebra; A. Celentano; I. Chakaberia; B. Chan; W. Chang; M. Chartier; C. Chatterjee; D. Chen; J. Chen; K. Chen; Z. Chen; H. Chetri; T. Chiarusi; M. Chiosso; X. Chu; J.J. Chwastowski; G. Cicala; E. Cisbani; E. Cline; I. Cloët; D. Colella; M. Contalbrigo; G. Contin; R. Corliss; Y. Corrales-Morales; J. Crafts; C. Crawford; R. Cruz-Torres; D. D'Ago; A. D'Angelo; N. D'Hose; J. Dainton; S. Dalla Torre; S.S. Dasgupta; S. Dash; N. Dashyan; J. Datta; M. Daugherity; R. De Vita; W. Deconinck; M. Defurne; K. Dehmelt; A. Del Dotto; F. Delcarro; G. Dellacasa; Z.S. Demiroglu; G.W. Deptuch; V. Desai; A. Deshpande; K. Devereaux; R. Dhillon; R. Di Salvo; C. Dilks; D. Dixit; S. Dobbs; X. Dong; J. Drachenberg; A. Drees; R. Dupré; M. Durham; R. Dzhygadlo; L. El Fassi; D. Elia; E. Epple; R. Esha; O. Evdokimov; O. Eyser; D. Falchieri; W. Fan; A. Fantini; R. Fatemi; S. Fazio; S. Fegan; A. Filippi; H. Fox; A. Francisco; A. Freeze; S. Furletov; Y. Furletova; C. Gal; S. Gardner; P. Garg; D. Gaskell; K. Gates; M.T.W. Gericke; F. Geurts; C. Ghosh; M. Giacalone; F. Giacomini; S. Gilchrist; D. Glazier; K. Gnanvo; L. Gonella; L.C. Greiner; N. Guerrini; L. Guo; A. Gupta; R. Gupta; W. Guryn; X. He; T. Hemmick; S. Heppelmann; D. Higinbotham; M. Hoballah; A. Hoghmrtsyan; M. Hohlmann; T. Horn; D. Hornidge; H.Z. Huang; C.E. Hyde; P. Iapozzuto; M. Idzik; B.V. Jacak; M. Jadhav; S. Jain; C. Jena; A. Jentsch; Y. Ji; Z. Ji; J. Jia; P.G. Jones; R.W.I. Jones; S. Joosten; S. Joshi; L. Kabir; G. Kalicy; G. Karyan; V.K.S. Kashyap; D. Kawall; H. Ke; M. Kelsey; J. Kim; J. Kiryluk; A. Kiselev; S.R. Klein; H. Klest; V. Kochar; W. Korsch; L. Kosarzewski; A. Kotzinian; F. Krizek; A. Kumar; K.S. Kumar; L. Kumar; R. Kumar; S. Kumar; A. Kunnath; N. Kushawaha; R. Lacey; Y.S. Lai; K. Lalwani; J. Landgraf; L. Lanza; D. Lattuada; M. Lavinsky; J.H. Lee; S.H. Lee; R. Lemmon; A. Lestone; N. Lewis; H. Li; S. Li; W. Li; W. Li; X. Li; X. Li; X. Liang; T. Ligonzo; T. Lin; J. Liu; K. Liu; M. Liu; K. Livingston; N. Liyanage; T. Ljubicic; O. Long; N. Lukow; Y. Ma; J. Mammei; F. Mammoliti; K. Mamo; I. Mandjavidze; S. Maple; D. Marchand; A. Margotti; C. Markert; P. Markowitz; T. Marshall; A. Martin; H. Marukyan; A. Mastroserio; S. Mathew; S. Mayilyan; C. Mayri; M. McEneaney; Y. Mei; L. Meng; F. Méot; J. Metcalfe; Z.-E. Meziani; P. Mihir; R. Milton; A. Mirabella; M. Mirazita; A. Mkrtchyan; H. Mkrtchyan; B. Mohanty; M. Mondal; A. Morreale; A. Movsisyan; D. Muenstermann; A. Mukherjee; C. Munoz Camacho; M.J. Murray; H. Mustafa; M. Myška; B.P. Nachman; K. Nagai; R. Naik; J.P. Naim; J. Nam; B. Nandi; E. Nappi; Md. Nasim; D. Neff; D. Neiret; P.R. Newman; M. Nguyen; S. Niccolai; M. Nie; F. Noferini; J. Norman; F. Noto; A.S. Nunes; T. O'Connor; G. Odyniec; V.A. Okorokov; M. Osipenko; B. Page; C. Palatchi; D. Palmer; P. Palni; S. Pandey; D. Panzieri; S. Park; K. Paschke; C. Pastore; R.N. Patra; A. Paul; S. Paul; C. Pecar; A. Peck; I. Pegg; C. Pellegrino; C. Peng; L. Pentchev; R. Perrino; K. Piotrzkowski; T. Polakovic; M. Płoskoń; M. Posik; S. Prasad; R. Preghenella; S. Priens; E. Prifti; M. Przybycien; P. Pujahari; A. Quintero; M. Radici; S.K. Radhakrishnan; S. Rahman; S. Rathi; B. Raue; R. Reed; P. Reimer; J. Reinhold; E. Renner; L. Rignanese; M. Ripani; A. Rizzo; D. Romanov; A. Roy; N. Rubini; M. Ruspa; L. Ruan; F. Sabatié; S. Sadhukhan; N. Sahoo; P. Sahu; D. Samuel; A. Sarkar; M. Sarsour; W. Schmidke; B. Schmookler; C. Schwarz; J. Schwiening; M. Scott; I. Sedgwick; M. Segreti; S. Sekula; R. Seto; N. Shah; A. Shahinyan; D. Sharma; N. Sharma; E.P. Sichtermann; A. Signori; A. Singh; B.K. Singh; S.N. Singh; N. Smirnov; D. Sokhan; R. Soltz; W. Sondheim; S. Spinali; F. Stacchi; R. Staszewski; P. Stepanov; S. Strazzi; I.R. Stroe; X. Sun; B. Surrow; Z. Sweger; T.J. Symons; V. Tadevosyan; A. Tang; E. Tassi; L. Teodorescu; F. Tessarotto; D. Thomas; J.H. Thomas; T. Toll; L. Tomášek; F. Torales-Acosta; P. Tribedy; Triloki; V. Tripathi; R. Trotta; M. Trzebiński; B.A. Trzeciak; O. Tsai; Z. Tu; R. Turrisi; C. Tuvè; T. Ullrich; G.M. Urciuoli; A. Valentini; S. Vallarino; M. Vandenbroucke; J. Vanek; G. Vino; G. Volpe; H. Voskanyan; A. Vossen; E. Voutier; G. Wang; Y. Wang; D. Watts; N. Wickramaarachchi; F. Wilson; C.-P. Wong; X. Wu; Y. Wu; J. Xie; Q.-H. Xu; Z. Xu; Z.W. Xu; C. Yang; Q. Yang; Y. Yang; Z. Ye; Z. Ye; L. Yi; Z. Yin; M. Yurov; N. Zachariou; J. Zhang; Y. Zhang; Z. Zhang; Z. Zhang; Y. Zhao; Y.X. Zhao; Z. Zhao; L. Zheng; M. Żurek
ATHENA has been designed as a general purpose detector capable of delivering the full scientific scope of the Electron-Ion Collider. Careful technology choices provide fine tracking and momentum resolution, high performance electromagnetic and hadronic calorimetry, hadron identification over a wide kinematic range, and near-complete hermeticity. This article describes the detector design and its expected performance in the most relevant physics channels. It includes an evaluation of detector technology choices, the technical challenges to realizing the detector and the R&D required to meet those challenges. © 2022 The Author(s).
CoCl2-Induced Biochemical Hypoxia Down Regulates Activities and Expression of Super Oxide Dismutase and Catalase in Cerebral Cortex of Mice
(Springer Science and Business Media, LLC, 2014) Anupama Rani; S. Prasad
Hypoxia-induced oxidative stress is one of the major hallmark reasons underlying brain dysfunction. In the present manuscript, we have used CoCl2-induced hypoxic mice to investigate alterations in the activities of chief antioxidative stress enzymes- superoxide dismutase (SOD) and catalase (CAT) and expression of their genes Sod1 and Cat in the cerebral cortex as this model has not been routinely used for carrying out such study. Hypoxia mimetic mice model was accordingly developed by oral CoCl2 administration to mice and validated by analyzing alterations in the expression of the hypoxia inducible factor gene Hif-1α and its immediate responsive genes. Our Western blot data demonstrated that a dose of 40 mg/kg BW of CoCl2 was able to generate hypoxia like condition in mice in which Hif-1α and its immediate responsive genes-glutamate transporter-1 (Slc2a1) and erythropoietin (Epo) expression were up regulated. Our in-gel assay data indicated that SOD and CAT activities significantly declined and it was associated with significant down regulation of Sod1 and Epo expression as evident from our semi quantitative RT-PCR and Western blot data, which might be correlated with up regulation of Hif-1α expression in the cerebral cortex of the CoCl2-treated hypoxic mice. Our findings suggest that CoCl2-induced hypoxic mouse model is useful for studying alterations in the anti oxidative enzymes and biochemical/molecular/neurobiological analysis of hypoxia-induced alterations in brain function. © 2014, Springer Science+Business Media New York.
Coexistence of Folded and Extended Conformations of a Tripeptide Containing α,α-Di-n-propylglycine in Crystals
(1994) S. Prasad; S. Mitra; E. Subramanian; D. Velmurugan; R.B. Rao; P. Balaram
The crystal structure of the tripeptide Boc-Leu-Dpg-Val-OMe (Dpg, α, α-di-n-propylglycine) reveals the coexistence of two distinct backbone conformations. In molecule A the Dpg residue adopts a fully extended conformation (φ = 76.0°, ψ =180.0°) while in molecule B a left handed helical conformation (φ = 62.8°, ψ = 39.6°) is observed. Molecule B adopts a folded structure corresponding to a highly distorted Type II β-turn conformation, which lacks an intramolecular 4 → 1 hydrogen bond. In contrast, molecule A has an open, extended conformation. The results demonstrate that both fully extended and helical conformations are energetically accessible to the Dpg residue. © 1994 Academic Press. All rights reserved.
Controlling emissivity in one dimensional photonic crystals using surface truncation
(Springer New York LLC, 2018) Y. Sharma; A. Aman; S. Prasad; V. Singh
The properties of emissivity in one dimensional photonic crystals are studied using transfer matrix method and Kirchhoff’s second law. It is found that emissivity and its angular distribution can be controlled by truncating the first layer. It is observed that with increase in incident angle, emissivity is shifted towards lower wavelength. From the studies of angular distribution of emissivity with truncation parameter, it is demonstrated that the magnitude of emissivity can be increased with truncation parameter while maintaining the same angular lobe. © 2017, Springer Science+Business Media, LLC, part of Springer Nature.
Controlling the electromagnetic density of modes in one-dimensional photonic crystal with defect using acoustic wave
(Canadian Science Publishing, 2018) Ayush Aman; S. Prasad
We have theoretically analyzed the effect of acoustic parameters on the electromagnetic density of modes (DOM) in a one-dimensional photonic crystal featuring a defect mode. The whole structure is modulated by a longitudinal acoustic wave. The transfer matrix method and Wigner time approach are used to calculate the transmittance and electromagnetic DOM, respectively. The results show that the electromagnetic DOM is dynamically controlled by the acoustic amplitude. A sharp peak in DOM is found at the defect site whose magnitude decreases with the increase in acoustic amplitude and shows periodic swing with fractional change in time period of acoustic wave. Furthermore, the result of polarization of electromagnetic wave is also discussed and it is found that the location of the defect mode can be modulated in a large frequency rage without changing the structure of the photonic crystal. © 2018 Published by NRC Research Press.