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Search Results: 1 - 10 of 461939 matches for " Barman A "
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Landau damping effects on dust-acoustic solitary waves in a dusty negative-ion plasma
A. Barman,A. P. Misra
Physics , 2014, DOI: 10.1063/1.4890571
Abstract: The nonlinear theory of dust-acoustic waves (DAWs) with Landau damping is studied in an unmagnetized dusty negative-ion plasma in the extreme conditions when the free electrons are absent. The cold massive charged dusts are described by fluid equations, whereas the two-species of ions (positive and negative) are described by the kinetic Vlasov equations. A Korteweg de-Vries (KdV) equation with Landau damping, governing the dynamics of weakly nonlinear and weakly dispersive DAWs, is derived following Ott and Sudan [Phys. Fluids {\bf 12}, 2388 (1969)]. It is shown that for some typical laboratory and space plasmas, the Landau damping (and the nonlinear) effects are more pronounced than the finite Debye length (dispersive) effects for which the KdV soliton theory is not applicable to DAWs in dusty pair-ion plasmas. The properties of the linear phase velocity, solitary wave amplitudes (in presence and absence of the Landau damping) as well as the Landau damping rate are studied with the effects of the positive ion to dust density ratio $(\mu_{pd})$ as well as the ratios of positive to negative ion temperatures $(\sigma)$ and masses $(m)$.
Oblique propagation of dust ion-acoustic solitary waves in a magnetized dusty pair-ion plasma
A. P. Misra,Arnab Barman
Physics , 2013, DOI: 10.1063/1.4886125
Abstract: We investigate the propagation characteristics of electrostatic waves in a magnetized pair-ion plasma with immobile charged dusts. It is shown that obliquely propagating (OP) low-frequency (in comparison with the negative-ion cyclotron frequency) long-wavelength "slow" and "fast" modes can propagate, respectively, as dust ion-acoustic (DIA) and dust ion-cyclotron (DIC)-like waves. The properties of these modes are studied with the effects of obliqueness of propagation $(\theta)$, the static magnetic field, the ratios of the negative to positive ion masses $(m)$ and temperatures $(T)$ as well as the dust to negative-ion number density ratio $(\delta)$. Using the standard reductive perturbation technique, we derive a Korteweg-de Vries (KdV) equation which governs the evolution of small-amplitude OP DIA waves. It is found that the KdV equation admits only rarefactive solitons in plasmas with $m$ well below its critical value $m_c~(\gg1)$ which typically depends on $T$ and $\delta$. It is shown that the nonlinear coefficient of the KdV equation vanishes at $m=m_c$, i.e., for plasmas with much heavier negative ions, and the evolution of the DIA waves is then described by a modified KdV (mKdV) equation. The latter is shown to have only compressive soliton solution. The properties of both the KdV and mKdV solitons are studied with the system parameters as above, and possible applications of our results to laboratory and space plasmas are briefly discussed.
Landau damping of Gardner solitons in a dusty bi-ion plasma
A. P. Misra,Arnab Barman
Physics , 2015, DOI: 10.1063/1.4927463
Abstract: The effects of linear Landau damping on the nonlinear propagation of dust-acoustic solitary waves (DASWs) are studied in a collisionless unmagnetized dusty plasma with two species of positive ions. The extremely massive, micron-seized, cold and negatively charged dust particles are described by fluid equations, whereas the two species of positive ions, namely the cold (heavy) and hot (light) ions are described by the kinetic Vlasov equations. Following Ott and Sudan [Phys. Fluids {\bf 12}, 2388 (1969)], and by considering lower and higher-order perturbations, the evolution of DASWs with Landau damping is shown to be governed by Korteweg-de Vries (KdV), modified KdV (mKdV) or Gardner (KdV-mKdV)-like equations. The properties of the phase velocity and the Landau damping rate of DASWs are studied for different values of the ratios of the temperatures $(\sigma)$ and the number densities $(\mu)$ of hot and cold ions as well the cold to hot ion mass ratio $m$. The distinctive features of the decay rates of the amplitudes of the KdV, mKdV and Gardner solitons with a small effect of Landau damping are also studied in different parameter regimes. It is found that the Gardner soliton points to lower wave amplitudes than the KdV and mKdV solitons. The results may be useful for understanding the localization of solitary pulses and associated wave damping (collisionless) in laboratory and space plasmas (e.g., the F-ring of Saturn) in which the number density of free electrons is much smaller than that of ions and the heavy, micron seized dust grains are highly charged.
Pulmonary Alveolar Proteinosis in Association with Congenital Dyserythropoietic Anemia: A Case Report
Marcus A. Carden,Ashish Barman,Gita Massey
Case Reports in Pediatrics , 2012, DOI: 10.1155/2012/624740
Abstract: A two-year-old girl with congenital dyserythropoietic anemia (CDA) acutely developed fever, tachypnea, and increased oxygen requirement. Chest X-ray revealed bilateral interstitial infiltrates and mild cardiomegaly. Blood cultures grew no infectious agents, while pulmonary specimens grew cytomegalovirus (CMV). Treatment with intravenous ganciclovir was initiated but without response. Final cytologic preparations of bronchoalveolar lavage (BAL) fluid revealed eosinophilic amorphous material consistent with pulmonary alveolar proteinosis (PAP). CDA and PAP are extremely rare disorders in pediatrics. PAP should be considered in patients with hematological disorders who present with acute interstitial pneumonia, after infectious causes are ruled out.
Botulinum toxin treatment of hemifacial spasm and blepharospasm : objective response evaluation.
Thussu A,Barman C,Prabhakar S
Neurology India , 1999,
Abstract: Twenty seven patients with hemifacial spasm (HFS) and sixteen patients with blepharospasm (BS) having mean Jankovic disability rating scale score of 2.56+0.58 SD and 2.81+0.54 SD, respectively, were treated with botulinum toxin A (BTX-A) injections. The total number of injection sessions were ninety one with relief response in 98.91%. The mean improvement in function scale score was 3.78+0.64 SD and 3.29+1.07 SD respectively, in HFS and BS groups. The clinical benefit induced by botulinum toxin lasted for a mean of 4.46+3.11 SD (range 2 to 13) months in HFS group and 2.66+1.37 SD (range 1 to 6) months, in BS groups. Transient ptosis was seen in 4.39% of total ninety one injection sessions. These findings show that local botulinum toxin treatment provides effective, safe and long lasting relief of spasms.
Antimicrobial Efficacy of Nut Oil of Semecarpus anacardium: A Marking Nut Tree
A. Sharma,N. Barman,M. Malwal
Biotechnology , 2010,
Abstract: The present investigation was undertaken to evaluate in vitro antimicrobial activity of Semecarpus anacardium L. (Anacardiaceae) nuts oils. Essential oil from nut of S. anacardium was extracted by hydro-distillation method in a Clevenger type apparatus. The antimicrobial screening of the isolated essential oil was performed against Gram positive-Bacillus subtilis (ATCC 6633), Staphylococcus aureus (ATCC 25923) Gram negative-Proteus vulgaris (ATCC 2027), Escherichia coli (ATCC 25922) and fungal strains Aspergillus niger (ATCC 16404), Aspergillus fumigates (ATCC 26933), Candida albicans (ATCC5027) and Candida glabrata (ATCC 66032) using disc diffusion method. The essential oil was found to be more or less active against almost all tested pathogenic strains with varied spectrum of inhibition zone (7.0±0.06-13.0±0.01 mm). The significant inhibitory effect was observed against Staphylococcus aureus (12.0±0.05 mm) and A. niger (13.0±0.01 mm). The significant potential of Semecarpus anacardium nut oil concludes that it could serve as a source of antimicrobial agents.
Pulmonary Alveolar Proteinosis in Association with Congenital Dyserythropoietic Anemia: A Case Report
Marcus A. Carden,Ashish Barman,Gita Massey
Case Reports in Pediatrics , 2012, DOI: 10.1155/2012/624740
Abstract: A two-year-old girl with congenital dyserythropoietic anemia (CDA) acutely developed fever, tachypnea, and increased oxygen requirement. Chest X-ray revealed bilateral interstitial infiltrates and mild cardiomegaly. Blood cultures grew no infectious agents, while pulmonary specimens grew cytomegalovirus (CMV). Treatment with intravenous ganciclovir was initiated but without response. Final cytologic preparations of bronchoalveolar lavage (BAL) fluid revealed eosinophilic amorphous material consistent with pulmonary alveolar proteinosis (PAP). CDA and PAP are extremely rare disorders in pediatrics. PAP should be considered in patients with hematological disorders who present with acute interstitial pneumonia, after infectious causes are ruled out. 1. Introduction Congenital dyserythropoietic anemia type II (CDA II), also known as HEMPAS (hereditary erythroblastic multinuclearity with positive acid serum test), is a rare hematological autosomal recessive disorder whereby individuals have bone marrow biopsy findings indicating inappropriate red blood cell lineage progression [1]. Pulmonary alveolar proteinosis (PAP) is also a rare disorder in which lipoproteinaceous material congregates within alveolar spaces, leading to a host with impaired pulmonary immunity and susceptibility to opportunistic infection [2]. Although historically reported in patients with various hematological disorders [3–8], to our knowledge, this is the first case report of PAP associated with CDA. 2. Case Report A 23-month-old girl presented to our facility with one week of worsening fevers, productive cough, and increased work of breathing. Over the previous 3 months, she was treated for presumed upper respiratory tract infections with inhaled beta-agonists, inhaled steroids, oral steroids, and several different oral antibiotics. Relevant medical history was significant for prematurity and severe anemia necessitating intrauterine blood transfusions, CDA diagnosed at 20 months by bone marrow biopsy and aspiration that was morphologically consistent with type II, and surgical placement of a Port-a-Cath for chronic blood transfusions. Initial vital signs were temperature 37.9 degrees Celsius, heart rate 156?bpm, respiratory rate 50/min with oxygen saturation 83% on room air and 98% on 1 LPM oxygen by nasal cannula, and blood pressure 115/61?mm?Hg. She appeared in mild distress with increased work of breathing. She had moderate frontal bossing with open anterior fontanelle. Heart examination was significant for a II/IV systolic ejection murmur. Lung exam revealed diffuse rales
Scaling of flat band potential and dielectric constant as a function of Ta concentration in Ta-TiO2 epitaxial films
Y. L. Zhao,A. Roy Barman,S. Dhar,A. Annadi
AIP Advances , 2011, DOI: 10.1063/1.3609927
Abstract: Electrochemical impedance spectroscopy measurements of pulsed laser deposited single crystal anatase TiO2 thin films with various concentrations of Ta substituting for Ti were carried out. The qualities of the films were characterized by X-ray diffraction and Rutherford back scattering-channeling measurements. UV-visible measurements show a systematic increase of the bandgap with Ta incorporation. Corresponding Mott-Schottky plot was applied to obtain a continuous shift of the flat band potential with increasing free charge carrier (provided by Ta) concentration. This was verified theoretically by ab initio calculation which shows that extra Ta d-electrons occupy Ti t2g orbital with increasing Ta concentration, thereby pushing up the Fermi level. The Mott-Schottky results were consistent when compared with Hall effect and temperature dependent resistivity measurements. From the measured deviation of carrier densities from Hall and Mott-Schottky measurements we have estimated the static dielectric constant of the TiO2 as a function of Ta incorporation, not possible from capacitive measurements.
Fatigue, Physical Function and Quality of Life in Relation to Disease Activity in Established Rheumatoid Arthritis
Barman A,Chatterjee A,Das KM,Mandal PK
Indian Journal of Physical Medicine and Rehabilitation , 2010,
Abstract: Objectives: This study was intended to find out therelationship of fatigue, functional disability and Health-Related Quality Of Life (HRQOL) with disease activityin adult patients with active rheumatoid arthritis (RA)and to observe the effect of rehabilitation programme onthese parameters.Material and Methods: 106 patients participated and 96completed the study. Disease Activity Score-28 (DAS-28), visual analogue scale for pain and fatigue,Multidimensional Assessment of Fatigue Scale (MAF),Health Assessment Questionnaire (HAQ), AmericanCollege of Rheumatology revised criteria for functionalstatus classification, World Health Organization QualityOf Life instrument (WHOQOL-BREF) wereadministered. A comprehensive rehabilitation programmecomprising pharmacologic and non-pharmacologic therapywas continued for 6 months.Results: Mean VAS fatigue, DAS28 & HAQ scores were45.68, 5.14 and 1.16 respectively. Significant correlation(Pearson’s r =0.82, p<0.05; r=0.75, p<0.05; r=0.85,p=<0.05) between the disease activity and the value ofthe VAS Fatigue, Global Fatigue (MAF) and HAQ scorerespectively and inverse co-relation between quality oflife (QOL) domain scores and disease activity wereobserved. Similar results were also found in the final visit.Comprehensive rehabilitation reduced the disease activity,fatigue, functional disability and improved QOL.Conclusion: High fatigue level, disability, pain anddecreased QOL characterized RA disease activity.Reduction of DAS, Fatigue, HAQ scores with treatmentimproved QOL.
Various Pathologies Causing Shoulder Pain: Their Relations with Demographic Parameters and Co- morbidities
Chatterjee A,Middya AK,Barman A,Das KM
Indian Journal of Physical Medicine and Rehabilitation , 2008,
Abstract: Background: Shoulder pain is a very common musculoskeletal disorder requiring physiatric intervention.However, most of the referred cases of pain shoulder come to PMR department as “frozen shoulder”, butcareful evaluation and investigations reveal a myriad of pathological conditions.Objectives: To find the distribution and incidence of various pathological conditions presenting as shoulderpain and its relation to demographic parameters and pre-existing pathologies & co-morbidities.Materials and Methods: Total number of 300 patients of either sex with pain shoulder and functionalimpairment were included in this cross-sectional observational study. Appropriate clinical examinations,radiological and other necessary investigations were done. Descriptive statistical tools were used for dataanalysis.Results: Majority were aging adults with higher incidence in females. Periarticular pathologies includingthose involving rotator cuff were seen to be the major cause of pain shoulder. There was an overall leftshoulder predominance but males tended to have right side involvement. Those with systemic diseaseshad more prevalence of bilateral involvement.Conclusion: Predominance of periarticular tissue pathologies as the cause of shoulder pain may be relatedwith its typical biomechanics. Relation was seen between heavy physical work and dominant side involvement.Systemic pathologies predispose to bilateral involvement.
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