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Sharun K, Sircar S, Malik YS, Singh RK, Dhama K. How close is SARS-CoV-2 to canine and feline coronaviruses? J Small Anim Pract 2020; 61:523-526. [PMID: 32785948 PMCID: PMC7436317 DOI: 10.1111/jsap.13207] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 06/22/2020] [Accepted: 07/02/2020] [Indexed: 11/30/2022]
Affiliation(s)
- K Sharun
- Division of Surgery, ICAR-Indian Veterinary Research Institute, Izatnagar, Bareilly, Uttar Pradesh, 243 122, India
| | - S Sircar
- Division of Biological Standardization, ICAR-Indian Veterinary Research Institute, Izatnagar, Bareilly, Uttar Pradesh, 243 122, India
| | - Y S Malik
- Division of Biological Standardization, ICAR-Indian Veterinary Research Institute, Izatnagar, Bareilly, Uttar Pradesh, 243 122, India
| | - R K Singh
- ICAR-Indian Veterinary Research Institute, Izatnagar, Bareilly, Uttar Pradesh, 243 122, India
| | - K Dhama
- Division of Pathology, ICAR-Indian Veterinary Research Institute, Izatnagar, Bareilly, Uttar Pradesh, 243 122, India
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Bevitori R, Sircar S, de Mello R, Togawa R, Côrtes M, Oliveira T, Grossi-de-Sá M, Parekh N. Research Article Identification of co-expression gene networks controlling rice blast disease during an incompatible reaction. Genet Mol Res 2020. [DOI: 10.4238/gmr18579] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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VinodhKumar OR, Sircar S, Pruthvishree BS, Nirupama KR, Singh BR, Sinha DK, Rupner R, Karthikeyan A, Karthikeyan R, Dubal ZB, Malik YS. Cross-sectional study on rotavirus A (RVA) infection and assessment of risk factors in pre- and post-weaning piglets in India. Trop Anim Health Prod 2019; 52:445-452. [PMID: 31313018 DOI: 10.1007/s11250-019-01999-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Accepted: 07/04/2019] [Indexed: 02/05/2023]
Abstract
Rotavirus A (RVA) infections are known to retard the piglets' growth and minimize the profit to the pig farming community. Between August 2014 and July 2017, in a cross-sectional study, we surveyed 13 organized pig farms located in the eight states of India representing northern, north-eastern and southern regions, to identify the risk factors associated with RVA infection in pre- and post-weaning piglets. Faecal samples (n = 411) comprising of non-diarrhoeic (n = 320) and diarrhoeic (n = 91) were collected and screened for RVA infection using VP6 gene-based RT-PCR. RVA positivity of 52.5% (168/320) in non-diarrhoeic and 59.3% (54/91) in diarrhoeic piglets was noticed. Further, 53.3% (120/225) and 54.8% (102/186) of the samples from pre- and post-weaned samples were positive for RVA, respectively. To note, no statistically significant association was noticed between RVA infection, health and weaning status. Additionally, a questionnaire-based survey was conducted to identify the risk factors for RVA infections in piglets. The analysis revealed that good ventilation (OR 0.2, 95% CI 0.15-0.39), use of deep well water (OR 0.2, 95% CI 0.13-0.43) and feeding of commercial feed (OR 0.3, 95% CI 0.18-0.41) were associated with reduced risk of RVA infection compared with poor ventilation, use of shallow well water and feeding of own milled feed, respectively. Contrarily, mixed farms (OR 2.1, 95% CI 1.26-3.37), use of heater or cooler (OR 5.9, 95% CI 3.74-9.30), sheds in different elevation (OR 2.5, 95% CI 1.20-5.01) and weekly and occasional use of disinfectant for surface cleaning (OR 1.8, 95% CI 1.12-2.96) were associated with higher RVA infection. Mitigating the risk factors might help in better health management of piglets and increase the economic return to pig farming community in the country.
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Affiliation(s)
- O R VinodhKumar
- Division of Epidemiology, ICAR-Indian Veterinary Research Institute, Bareilly, 243122, India.
| | - S Sircar
- Division of Biological Standardization, ICAR-Indian Veterinary Research Institute, Izatnagar, Bareilly, Uttar Pradesh, 243122, India
| | - B S Pruthvishree
- Veterinary Clinical Complex, Veterinary College, Gadag, Karnataka, 582101, India
| | - K R Nirupama
- Division of Epidemiology, ICAR-Indian Veterinary Research Institute, Bareilly, 243122, India
| | - B R Singh
- Division of Epidemiology, ICAR-Indian Veterinary Research Institute, Bareilly, 243122, India
| | - D K Sinha
- Division of Epidemiology, ICAR-Indian Veterinary Research Institute, Bareilly, 243122, India
| | - Ramkumar Rupner
- Division of Epidemiology, ICAR-Indian Veterinary Research Institute, Bareilly, 243122, India
| | - A Karthikeyan
- Division of Epidemiology, ICAR-Indian Veterinary Research Institute, Bareilly, 243122, India
| | - R Karthikeyan
- Division of Epidemiology, ICAR-Indian Veterinary Research Institute, Bareilly, 243122, India
| | - Z B Dubal
- Division of Veterinary Public Health, ICAR-Indian Veterinary Research Institute, Bareilly, 243122, India
| | - Y S Malik
- Division of Biological Standardization, ICAR-Indian Veterinary Research Institute, Izatnagar, Bareilly, Uttar Pradesh, 243122, India.
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Affiliation(s)
- S. Sircar
- Department of Chemical and Biomolecular Engineering, Lehigh University, Bethlehem, Pennsylvania 18015, United States
| | - T. C. Golden
- Air Products and Chemicals, Inc., Allentown, Pennsylvania 18195, United States
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Abstract
The separation and purification of gas mixtures by adsorption has found numerous industrial applications during the past 30 years. The very active research and development in this field is driven by (a) the highly flexible nature of cyclic adsorptive process designs, (b) the availability of many adsorbents for the separation and (c) the multiple choice of adsorbent–process design combinations for achieving the desired separation goals. The trend is to improve the product quality and separation efficiency, as well as to increase the scale of application of this technology. The design of processes using faster cycles and the use of innovative adsorber configurations are two new directions. Hybrid gas separation and production concepts such as adsorbent membranes and simultaneous sorption–reaction schemes are emerging areas that may open new frontiers of application for this technology.
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Affiliation(s)
- S. Sircar
- Air Products and Chemicals, Inc., 7201 Hamilton Boulevard, Allentown, PA 18195-1501, U.S.A
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Affiliation(s)
- D.V. Cao
- Air Products and Chemicals, Inc., 7201 Hamilton Boulevard, Allentown, PA 18195-1501, U.S.A
| | - S. Sircar
- Air Products and Chemicals, Inc., 7201 Hamilton Boulevard, Allentown, PA 18195-1501, U.S.A
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Sircar S, Nguyen G, Kotousov A, Roberts AJ. Ligand-mediated adhesive mechanics of two static, deformed spheres. Eur Phys J E Soft Matter 2016; 39:95. [PMID: 27771859 DOI: 10.1140/epje/i2016-16095-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Accepted: 09/21/2016] [Indexed: 06/06/2023]
Abstract
A self-consistent model is developed to investigate attachment/detachment kinetics of two static, deformable microspheres with irregular surface and coated with flexible binding ligands. The model highlights how the microscale binding kinetics of these ligands as well as the attractive/repulsive potential of the charged surface affects the macroscale static deformed configuration of the spheres. It is shown that in the limit of smooth, neutrally charged surface (i.e., the dimensionless inverse Debye length, [Formula: see text]), interacting via elastic binders (i.e., the dimensionless stiffness coefficient, [Formula: see text]) the adhesion mechanics approaches the regime of application of the JKR theory, and in this particular limit, the contact radius, Rc, scales with the particle radius, R, according to the scaling law, [Formula: see text]. We show that static, deformed, highly charged, ligand-coated surface of micro-spheres exhibit strong adhesion. Normal stress distribution within the contact area adjusts with the binder stiffness coefficient, from a maximum at the center to a maximum at the periphery of the region. Although reported in some in vitro experiments involving particle adhesion, until now a physical interpretation for this variation of the stress distribution for deformable, charged, ligand-coated microspheres is missing. Surface roughness results in a diminished adhesion with a distinct reduction in the pull-off force, larger separation gap, weaker normal stress and limited area of adhesion. These results are in agreement with the published experimental findings.
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Affiliation(s)
- Sarthok Sircar
- School of Mathematical Sciences, University of Adelaide, SA 5005, Adelaide, Australia.
| | - Giang Nguyen
- School of Civil, Environmental and Mining Engineering, University of Adelaide, SA 5005, Adelaide, Australia
| | - Andrei Kotousov
- School of Mechanical Engineering, University of Adelaide, SA 5005, Adelaide, Australia
| | - Anthony J Roberts
- School of Mathematical Sciences, University of Adelaide, SA 5005, Adelaide, Australia
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Abstract
Separation and purification of gaseous mixtures by adsorption has become a valuable tool in the chemical industry. Gas adsorption operations require information on both equilibrium and kinetics. Analytical equations are available to describe the adsorption of pure gases; mixture equilibria can be predicted by thermodynamic methods. Kinetic data suitable for column design can be expressed in terms of overall mass transfer coefficients. Design of columns for thermal swing adsorption (TSA) or pressure swing adsorption (PSA) processes requires the simultaneous solution of the partial differential equations for the material, energy and momentum balances describing the dynamics of adsorption in columns. Numerical solutions are usually required, but some useful analytical solutions are available for special cases.
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Affiliation(s)
- S. Sircar
- Air Products and Chemicals, Inc., PO Box 538, Allentown, PA 18105 and Department of Chemical Engineering, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - A. L. Myers
- Air Products and Chemicals, Inc., PO Box 538, Allentown, PA 18105 and Department of Chemical Engineering, University of Pennsylvania, Philadelphia, PA 19104, USA
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Affiliation(s)
- S. Sircar
- Air Products and Chemicals, Inc., Allentown, Pennsylvania, 18105, USA
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Abstract
Separation of ethanol–water liquid mixtures can be carried out by selective adsorption of water on activated alumina. The moderate selectivity and heat of adsorption of water on the alumina permits easier and less energy intensive desorption of the adsorbed water. Experimental binary surface excess isotherms, liquid-phase adsorption kinetics and column dynamics for the adsorption of bulk water–ethanol mixtures on Alcoa H152 alumina are reported. Model analyses of the data are carried out to quantify the selectivity of adsorption, adsorptive mass-transfer coefficients and the properties of the mass-transfer zones in adsorption columns.
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Affiliation(s)
- M.B. Rao
- Air Products and Chemicals Inc., 7201 Hamilton Boulevard, Allentown, PA 18195, USA
| | - S. Sircar
- Air Products and Chemicals Inc., 7201 Hamilton Boulevard, Allentown, PA 18195, USA
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Rama Rao V, Wu CW, Kothare MV, Sircar S. Comparative Perfomances of Two Commercial Samples of LiLSX Zeolite for Production of 90% Oxygen from Air by a Novel Rapid Pressure Swing Adsorption System. SEP SCI TECHNOL 2015. [DOI: 10.1080/01496395.2014.976876] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Abstract
We present a multi-scale model to study the attachment of spherical particles with a rigid core, coated with binding ligands and suspended in the surrounding, quiescent fluid medium. This class of fluid-immersed adhesion is widespread in many natural and engineering settings, particularly in microbial surface adhesion. Our theory highlights how the micro-scale binding kinetics of these ligands, as well as the attractive/repulsive surface potential in an ionic medium affects the eventual macro-scale size distribution of the particle aggregates (flocs). The bridge between the micro-macro model is made via an aggregation kernel. Results suggest that the presence of elastic ligands on the particle surface lead to the formation of larger floc aggregates via efficient inter-floc collisions (i.e. non-zero sticking probability, g). Strong electrolytic composition of the surrounding fluid favours large floc formation as well. The kernel for the Brownian diffusion for hard spheres is recovered in the limit of perfect binding effectiveness (g→1) and in a neutral solution with no dissolved salts.
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Affiliation(s)
- Sarthok Sircar
- a School of Mathematical Sciences , University of Adelaide , Adelaide , SA 5000 , Australia
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Abstract
To understand the adhesion-fragmentation dynamics of bacterial aggregates (i.e., flocs), we model the aggregates as two ligand-covered rigid spheres. We develop and investigate a model for the attachment/detachment dynamics in a fluid subject to a homogeneous planar shear-flow. The binding ligands on the surface of the flocs experience attractive and repulsive surface forces in an ionic medium and exhibit finite resistance to rotation (via bond tilting). For certain range of material and fluid parameters, our results predict a nonlinear or hysteretic relationship between the binding/unbinding of the floc surface and the net floc velocity (translational plus rotational velocity). We show that the surface adhesion is promoted by increased fluid flow until a critical value, beyond which the bonds starts to yield. Moreover, adhesion is not promoted in a medium with low ionic strength, or flocs with bigger size or higher binder stiffness. The numerical simulations of floc-aggregate number density studies support these findings.
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Affiliation(s)
- Sarthok Sircar
- Department of Applied Mathematics, University of Colorado, Boulder, CO 80309, United States
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Sircar S, Keener JP, Fogelson AL. The effect of divalent vs. monovalent ions on the swelling of mucin-like polyelectrolyte gels: governing equations and equilibrium analysis. J Chem Phys 2013; 138:014901. [PMID: 23298059 DOI: 10.1063/1.4772405] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We introduce a comprehensive model of a mucin-like polyelectrolyte gel swelling-deswelling which includes the ion-mediated crosslinking of polymer strands and the exchange of divalent and monovalent ions in the gel. The gel is modeled as a multi-phase mixture which accounts for the polymer and solvent volume fractions and velocities as well as ionic species concentrations. Motion is determined by force balances involving viscous, drag, and chemical forces. The chemical forces are derived from a free energy which includes entropic contributions as well as the chemical and electrostatic interactions among the crosslinked polymer, uncrosslinked polymer, and the ionic solvent. The unified derivation produces all the classical effects (van't Hoff osmotic pressure, Donnan equilibrium potential, Nernst-Planck motion of ions) as well as expressions for Flory interaction parameter and the standard free energy parameters that explicitly depend on the gel chemistry and crosslink structure. For this model, we show how the interplay between ionic bath concentrations, ionic binding, and transient divalent crosslinking leads to a variety of swelled and deswelled phases/phase transitions. In particular, we show how the absorption of divalent ions can lead to a massive deswelling of the gel. We conclude that the unique properties of mucin-like gels can be explained by their ionic binding affinities and transient divalent crosslinking.
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Affiliation(s)
- S Sircar
- Department of Mathematics, University of Utah, Salt Lake City, Utah 84112, USA
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Nandi UN, Sircar S, Karmakar A, Giri S. Nonlinearity exponent of ac conductivity in disordered systems. J Phys Condens Matter 2012; 24:265601. [PMID: 22653102 DOI: 10.1088/0953-8984/24/26/265601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We measured the real part of ac conductance Σ(x,f) or Σ(T,f) of iron-doped mixed-valent polycrystalline manganite oxides LaMn(1-x)Fe(x)O(3) as a function of frequency f by varying initial conductance Σ(0) by quenched disorder x at a fixed temperature T (room) and by temperature T at a fixed quenched disorder x. At a fixed temperature T, Σ(x,f) of a sample with fixed x remains almost constant at its zero-frequency dc value Σ(0) at lower frequency. With increase in f, Σ(x,f) increases slowly from Σ(0) and finally increases rapidly following a power law with an exponent s at high frequency. Scaled appropriately, the data for Σ(T,f) and Σ(x,f) fall on the same universal curve, indicating the existence of a general scaling formalism for the ac conductivity in disordered systems. The characteristic frequency f(c) at which Σ(x,f) or Σ(T,f) increases for the first time from Σ(0) scales with initial conductance Σ(0) as f(c) ~ Σ(0)(x(f)), where x(f) is the onset exponent. The value of x(f) is nearly equal to one and is found to be independent of x and T. Further, an inverse relationship between x(f) and s provides a self-consistency check of the systematic description of Σ(x,f) or Σ(T,f). This apparent universal value of x(f) is discussed within the framework of existing theoretical models and scaling theories. The relevance to other similar disordered systems is also highlighted.
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Affiliation(s)
- U N Nandi
- Department of Physics, Scottish Church College, Kolkata, India.
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Keener JP, Sircar S, Fogelson AL. Influence of the standard free energy on swelling kinetics of gels. Phys Rev E Stat Nonlin Soft Matter Phys 2011; 83:041802. [PMID: 21599193 PMCID: PMC6097847 DOI: 10.1103/physreve.83.041802] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2010] [Indexed: 05/30/2023]
Abstract
Classical theories of gel swelling employ the mixing free energy, thereby ignoring any effects of the free energy of the pure phases,i.e., the polymer standard free energy. In this paper we present a model for the swelling kinetics of gels that incorporates the free energy, including the polymer standard free energy. We provide a complete analysis of how the swelling kinetics and stable states and sizes of the swelled gel depends on the free energy parameters and show that theories that use only the mixing free energy cannot correctly describe equilibrium states or the swelling kinetics.
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Affiliation(s)
- James P Keener
- Department of Mathematics, University of Utah, Salt Lake City, Utah 84112, USA
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Sircar S, Wang Q. Shear-induced mesostructures in biaxial liquid crystals. Phys Rev E Stat Nonlin Soft Matter Phys 2008; 78:061702. [PMID: 19256853 DOI: 10.1103/physreve.78.061702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2008] [Indexed: 05/27/2023]
Abstract
We study nematodynamics of a mesoscopic system consisting of sheared biaxial liquid crystalline polymers using a hydrodynamical kinetic theory. We solve the governing Smoluchowski equation using the Galerkin method in selected regions of the material parameter space and a range of accessible shear rates to investigate stable mesoscopic states and robust structures. The imposed shear flow breaks the rotational symmetry in the quiescent state to induce truly biaxial flow-aligning steady states, logrolling states, out-of-plane steady states, exotic time-periodic motions, and chaotic motions in different regimes of material parameters and shear rates.
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Affiliation(s)
- Sarthok Sircar
- Department of Mathematics, University of South Carolina, Columbia, South Carolina 29208, USA.
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Lee KB, Verdooren A, Caram HS, Sircar S. Chemisorption of carbon dioxide on potassium-carbonate-promoted hydrotalcite. J Colloid Interface Sci 2007; 308:30-9. [PMID: 17250846 DOI: 10.1016/j.jcis.2006.11.011] [Citation(s) in RCA: 135] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2006] [Revised: 11/01/2006] [Accepted: 11/01/2006] [Indexed: 11/16/2022]
Abstract
New equilibrium and column dynamic data for chemisorption of carbon dioxide from inert nitrogen at 400 and 520 degrees C were measured on a sample of potassium-carbonate-promoted hydrotalcite, which was a reversible chemisorbent for CO(2). The equilibrium chemisorption isotherms were Langmuirian in the low-pressure region (p(CO(2)) < 0.2 atm) with a large gas-solid interaction parameter. The isotherms deviated from Langmuirian behavior in the higher pressure region. A new analytical model that simultaneously accounted for Langmuirian chemisorption of CO(2) on the adsorbent surface and additional reaction between the gaseous and sorbed CO(2) molecules was proposed to describe the measured equilibrium data. The model was also capable of describing the unique loading dependence of the isosteric heat of chemisorption of CO(2) reported in the literature. The column breakthrough curves for CO(2) sorption from inert N(2) on the chemisorbent could be described by the linear driving force (LDF) model in conjunction with the new sorption isotherm. The CO(2) mass-transfer coefficients were (i) independent of feed gas CO(2) concentration in the range of the data at a given temperature and (ii) a weak function of temperature. The ratio of the mass-transfer zone length to the column length was very low due to highly favorable CO(2) sorption equilibrium.
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Affiliation(s)
- K B Lee
- Department of Chemical Engineering, Lehigh University, 111 Research Drive, Bethlehem, PA 18015-4791, USA
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Affiliation(s)
- S. Sircar
- a AIR PRODUCTS AND CHEMICALS, INC. ALLENTOWN , PENNSYLVANIA , 18105
| | - A. L. Myers
- b DEPARTMENT OF CHEMICAL ENGINEERING , UNIVERSITY OF PENNSYLVANIA PHILADELPHIA , PENNSYLVANIA , 19104
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Affiliation(s)
- D. V. Cao
- Air Products and Chemicals, Inc., 7201 Hamilton Boulevard, Allentown, Pennsylvania 18195-1501
| | - S. Sircar
- Air Products and Chemicals, Inc., 7201 Hamilton Boulevard, Allentown, Pennsylvania 18195-1501
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Sircar S. Misconceptions in physiology. Adv Physiol Educ 2000; 24:62-63. [PMID: 11209567 DOI: 10.1152/advances.2000.24.1.62] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Affiliation(s)
- D. V. Cao
- Air Products and Chemicals, Inc., Allentown, Pennsylvania 18195-1501
| | - R. J. Mohr
- Air Products and Chemicals, Inc., Allentown, Pennsylvania 18195-1501
| | - M. B. Rao
- Air Products and Chemicals, Inc., Allentown, Pennsylvania 18195-1501
| | - S. Sircar
- Air Products and Chemicals, Inc., Allentown, Pennsylvania 18195-1501
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Misra V, Gupta SC, Tandon SP, Gupta AK, Sircar S. Cytohistological study of urinary bladder neoplasms. INDIAN J PATHOL MICR 2000; 43:303-9. [PMID: 11218677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023] Open
Abstract
Eighty patients presenting with painless hematuria and 24 patients of transitional cell carcinoma bladder coming for follow up were included in this study to assess the role of exfoliative (voided urine) and lavage (saline lavage) cytology in initial diagnosis and follow up of the patient with carcinoma bladder. Freshly voided urine samples and saline lavage bladder washing samples were collected. A thorough cystoscopic examination was done and biopsy was taken from any apparent growth. Cytological smears were stained with hematoxylene and eosin and PAP's stain, histology sections were stained with hematoxylene and eosin. A statistically significant correlation (p < 0.001) was observed between the increasing grade of malignancy and cytopositivity. A good association was observed between histology and two methods of cytology (p < 0.01). The sensitivity, specificity and overall diagnostic accuracy of lavage cytology was more as compared to exfoliative cytology (71.05%, 56.0%, 78.85% Vs 47.37%, 41.18% and 61.54%). Cystopositivity was more with single large sessile tumour as compared to multiple small pedunculated tumours. Cytohistological discrepancy was observed in patients of transitional cell carcinoma with recurrence. It is concluded that cytology may act as a good adjuvant to histology in picking up early flat lesions and/or follow up of patients with transitional cell carcinoma.
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Affiliation(s)
- V Misra
- Department of Pathology, MLN Medical College, Allahabad
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Abstract
Adenoviruses encode a cysteine protease, adenain, required for uncoating and virion maturation. Adenain activity is regulated by an 11-amino-acid peptide cofactor thiol-bonded distal to the active site. Structural and experimental data suggest that the peptide might stabilize adenain in an optimal conformation for enzyme activity by bridging two noncontiguous regions of the molecule. The sequence requirements for this mechanism were examined both in vitro and ex vivo by means of mutant peptides and databank analysis. The results of in vitro experiments suggested that activation is not an all or nothing mechanism. With the exception of the smallest peptide, the mutant peptides bound to adenain, activated it, and competed with the wild-type peptide, but all of this occurred with reduced efficiency. When added to the medium of infected cells, most of the peptides inhibited infectious virus production to varying degrees in a dose-dependent manner and in accordance with their in vitro activity on adenain. We interpret this inhibition to be due to unscheduled adenain activation. Examination of the activation peptide sequences from 19 adenovirus serotypes revealed a limited number of conserved sequence features. These features were in agreement with the experimental data. We conclude that binding and activation of adenain by pVIc may be reversible and this reversibility may be an integral aspect of the in vivo regulation of enzyme activity in the course of virus assembly. The peptide cofactor binding domain is therefore a potential target for the development of anti-adenoviral agents.
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Affiliation(s)
- A Ruzindana-Umunyana
- Departement de Microbiologie et d'Infectiologie, Universite de Sherbrooke, Sherbrooke, Quebec, J1H 5N4, Canada
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Ruzindana-Umunyana A, Sircar S, Schick C, Silverman GA, Weber JM. Adenovirus endopeptidase hydrolyses human squamous cell carcinoma antigens in vitro but not ex vivo. Virology 2000; 268:141-6. [PMID: 10683336 DOI: 10.1006/viro.1999.0139] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The serpins SCCA1 and SCCA2 are highly expressed in the epithelium of the conducting airways, a common site of infection by group C adenoviruses, such as human adenovirus type 2 (Ad2). Based on the common location we examined a possible interaction between them. In vitro experiments with recombinant proteins showed that SCCA1 inhibited the viral protease in a dose-dependent manner. Both serpins were cleaved in a manner consistent with hydrolysis within their reactive site loop, without the formation of an SDS-resistant complex, as in the case of papain. Infection of SCCA1-expressing cells did not result in the cleavage of SCCA1, nor was the yield of infectious virus affected as compared to SCCA1-negative parental cells. This may be due to differential localization, the serpin being cytoplasmic and viral protease being nuclear. Surprisingly, however, virus infection, which tends to inhibit host protein synthesis, caused a significant increase in SCCA1 expression well into the late phase of infection.
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Affiliation(s)
- A Ruzindana-Umunyana
- Department of Microbiology, University of Sherbrooke, Sherbrooke, Quebec, J1H 5N4, Canada
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Affiliation(s)
- S. Sircar
- Air Products and Chemicals, Inc., 7201 Hamilton Boulevard, Allentown, Pennsylvania 18195-1501
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Affiliation(s)
- S. Sircar
- Air Products
and Chemicals, Inc., 7201
Hamilton Boulevard, Allentown, Pennsylvania 18195-1501
| | - R. Mohr
- Air Products
and Chemicals, Inc., 7201
Hamilton Boulevard, Allentown, Pennsylvania 18195-1501
| | - C. Ristic
- Air Products
and Chemicals, Inc., 7201
Hamilton Boulevard, Allentown, Pennsylvania 18195-1501
| | - M. B. Rao
- Air Products
and Chemicals, Inc., 7201
Hamilton Boulevard, Allentown, Pennsylvania 18195-1501
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Abstract
Adenoviruses encode a cysteine protease (AVP) which carries out highly specific cleavages on at least seven viral proteins and two cellular proteins. Virus infectivity is dependent on this function. The three-dimensional positions of the amino acids involved in catalysis display a striking similarity to those of papain, suggesting a similar catalytic mechanism. This similarity has prompted us to compare the effect of papain inhibitors on the two enzymes. AVP and papain activity was tested on a fluorescent peptide substrate as well as on metabolically labeled adenovirus (Ad2) precursor proteins. Hep2 cells infected with Ad2 were exposed to inhibitors and assayed for, (a) infectious virus, (b) in situ Ad2 protease activity, (c) physical particle production and their polypeptide composition. We found that in both substrate systems AVP was sensitive to the papain inhibitors benzamidoacetonitrile, acetamidoacetonitrile and N-methoxyphenylalanine glycylnitrile, and that the degree of sensitivity was influenced by the substrate. Unlike papain, AVP was relatively insensitive to E64. In ex vivo tests, Hep2 cells infected with Ad2 were exposed to inhibitors and assayed for, (a) infectious virus, (b) in situ Ad2 protease activity, (c) physical particle production and their polypeptide composition. A 4-fold reduction in virus titer was obtained when the inhibitors were added between 17 and 25 h after infection. Processing of precursor proteins was also inhibited yet the production of physical particles was only reduced 2-fold. These experiments show that papain inhibitors are also capable of inhibiting the adenovirus protease both in vitro and ex vivo, thus forging a possible link between structural similarity and functionality.
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Affiliation(s)
- S Sircar
- Department of Microbiology, Faculty of Medicine, University of Sherbrooke, Que., Canada
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Sircar S, Kansra U. Choice of cooking oils--myths and realities. J Indian Med Assoc 1998; 96:304-7. [PMID: 10063298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
In contrast to earlier epidemiologic studies showing a low prevalence of atherosclerotic heart disease (AHD) and type-2 dependent diabetes mellitus (Type-2 DM) in the Indian subcontinent, over the recent years, there has been an alarming increase in the prevalence of these diseases in Indians--both abroad and at home, attributable to increased dietary fat intake. Replacing the traditional cooking fats condemned to be atherogenic, with refined vegetable oils promoted as "heart-friendly" because of their polyunsaturated fatty acid (PUFA) content, unfortunately, has not been able to curtail this trend. Current data on dietary fats indicate that it is not just the presence of PUFA but the type of PUFA that is important--a high PUFA n-6 content and high n-6/n-3 ratio in dietary fats being atherogenic and diabetogenic. The newer "heart-friendly" oils like sunflower or safflower oils possess this undesirable PUFA content and there are numerous research data now available to indicate that the sole use or excess intake of these newer vegetable oils are actually detrimental to health and switching to a combination of different types of fats including the traditional cooking fats like ghee, coconut oil and mustard oil would actually reduce the risk of dyslipidaemias, AHD and Type-2 DM.
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Affiliation(s)
- S Sircar
- Department of Medicine, Safdarjang Hospital, New Delhi
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