This study covers optimization of I-sectional flange beams. Scope of this study is limited to med... more This study covers optimization of I-sectional flange beams. Scope of this study is limited to medium weight flange beams of Table 1 of IS 808:1983 but it can be further extended for the other sections of this code. Best possible geometric shape of the cross-section is found for maximum performance of the beam with minimum material consumption. All possible loading conditions are considered in the study for which a beam in flexure undergoes in its life. ANSYS software program is used for the analysis and optimizing the sections. It is found that sections MB 125, MB 300 and MB 400 of Table 1 of IS 808 are not the optimum sections but other alternative of these crosssections is available which within the same material consumption performs better than these sections of IS code.
Human population is constantly exposed to health risks by exposure to chemicals belonging to vari... more Human population is constantly exposed to health risks by exposure to chemicals belonging to various classes such as pesticides, pollutants and chemicals used in agriculture, food industries etc. It is important to keep use of such chemicals under continuous observation and their effects must be re-evaluated in the light of changing conditions of use and new scientific information (Council directive 89/107/EEC). Major part of my thesis is focused on investigating toxic effects and mechanisms of action of one such environmental pollutant, glyphosate, a non-selective herbicide. In this thesis, mechanistic toxicology of sodium benzoate (SB), a common food preservative, has also been investigated. I have used zebrafish vertebrate animal model for toxicity studies included in my thesis and therefore I have also established a zebrafish research lab at IITH. Glyphosate is a non-selective herbicide. Results included in my thesis indicate significant acute toxicity in zebrafish embryos expos...
Biochemical and Biophysical Research Communications, 2019
Glyphosate, an herbicide used worldwide, has emerged as a pollutant. However, its toxic effects a... more Glyphosate, an herbicide used worldwide, has emerged as a pollutant. However, its toxic effects are debated by regulatory authorities. Therefore, it is essential to keep the use of such chemicals under continuous observation, and their effects must be re-evaluated. We used zebrafish embryos to evaluate the toxic effects of glyphosate and its mechanisms. We found that glyphosate induced significant toxicity in a time and concentration-dependent manner. We observed an LD 50 of 66.04 ± 4.6 mg/mL after 48 h of exposure. Glyphosate significantly reduced the heartbeat in a time and concentration-dependent manner indicating cardiotoxicity. Selective downregulation of Cacana1C (L-type calcium channel) and ryr2a (Ryanodine receptor) genes along with selective upregulation of hspb11 (heat shock protein) gene was observed upon exposure to glyphosate indicating alterations in the calcium signaling. A reduction in the nitric oxide (NO) generation was also observed in the zebrafish embryos upon exposure to glyphosate. Our results indicate that glyphosate induces significant toxicity including cardiotoxicity in zebrafish embryos in a time and concentration-dependent manner. Further, cardiotoxicity may be due to changes in calcium and NO signaling.
Voltage-gated calcium channels (VGCCs) are the predominant source of calcium influx in the heart ... more Voltage-gated calcium channels (VGCCs) are the predominant source of calcium influx in the heart leading to calcium-induced calcium release and ultimately excitation-contraction coupling. In the heart, VGCCs are modulated by the β-adrenergic signaling. Signaling through β-adrenergic receptors (βARs) and modulation of VGCCs by β-adrenergic signaling in the heart are critical signaling and changes to these have been significantly implicated in heart failure. However, data related to calcium channel dysfunction in heart failure is divergent and contradictory ranging from reduced function to no change in the calcium current. Many recent studies have highlighted the importance of functional and spatial microdomains in the heart and that may be the key to answer several puzzling questions. In this review, we have briefly discussed the types of VGCCs found in heart tissues, their structure, and significance in the normal and pathological condition of the heart. More importantly, we have re...
For the assessment of cardiac function, heartbeat represents one key parameter. Current methods o... more For the assessment of cardiac function, heartbeat represents one key parameter. Current methods of heartbeat measurements in the zebrafish larvae usually require larval immobilization, fluorescent transgenic strains and a confocal microscope, costly commercial software for analysis, or strong programming skills if the software is open-source. Here, we present a simple yet powerful method of heartbeat analysis using untethered, unlabeled zebrafish larva using ImageJ (open-source software), which does not require programming skills. We named it as ZebraPace for Zebrafish Precise Algorithm for Cardiac-rhythm Estimation. ZebraPace works directly with AVI videos and requires no image processing steps. ZebraPace uses pixel intensity change in a grayscale video to count the number of beats. We have validated the ZebraPace method by pharmacological alterations of the heartbeat in zebrafish larvae of 48 and 72 hpf stages. We have also determined beat-to-beat interval, which relates to rhythm...
Biochemical and biophysical research communications, Jul 20, 2018
Sodium benzoate (SB) is a common food preservative. Its FDA described safety limit is 1000 ppm. L... more Sodium benzoate (SB) is a common food preservative. Its FDA described safety limit is 1000 ppm. Lately, increased use of SB has prompted investigations regarding its effects on biological systems. Data regarding toxicity of SB is divergent and controversial with studies reporting both harmful and beneficial effects. Therefore, we did a systematic dose dependent toxicity study of SB using zebrafish vertebrate animal model. We also investigated oxidative stress and anxiety-like behaviour in zebrafish larva treated with SB. Our results indicate that SB induced developmental (delayed hatching), morphological (pericardial edema, yolk sac edema and tail bending), biochemical (oxidative stress) and behavioural (anxiety-like behaviour) abnormalities in developing zebrafish larva. LC of SB induced toxicity was approximately 400 ppm after 48 h of SB exposure. Our study strongly supports its harmful effects on vertebrates at increasing doses. Thus, we suggest caution in the excessive use of th...
The article demonstrates a novel approach for material nonlinear analysis. This analysis procedur... more The article demonstrates a novel approach for material nonlinear analysis. This analysis procedure eliminates tedious and lengthy step by step incremental and then iterative procedure adopted classically and gives direct results in the linear as well as in nonlinear range of the material behavior. It is found that the methodology is very suitable to apply for the brittle material such as concrete and composite materials. One dimensional problem of a simple bar is solved to formulate fundamental procedure and basics of the method. Another two dimensional problem of beam bending is solved for further strengthening the method. It is found that it is an excellent computational procedure adopted so far for material nonlinear analysis which gives very accurate results, easy to adopt and simple in calculations. The method not only eliminates linearity assumptions in its derivations and calculations but also eliminates all types of possibility of errors in the analysis procedure.
This article demonstrates a new approach for nonlinear finite element analysis. The methodology i... more This article demonstrates a new approach for nonlinear finite element analysis. The methodology is very suitable and gives very accurate results in linear as well as in nonlinear range of the material behavior. Proposed methodology can be regarded as stress based finite element analysis as it is required to define the stress distribution within the structural body with structural idealization and modelling assumptions. The methodology eliminates the lengthy and tedious procedure of step by step and then iterative procedure adopted classically for nonlinear analysis problems. One dimensional problem of a simple bar loaded axially is solved to formulate the basic principles. Two dimensional problem of a cantilever beam bending and a torsional problem are solved for further demonstrating and strengthening the method. Results of torsional problem are verified with experimental results. The method is applicable for material nonlinear analysis only.
This paper demonstrates a novel formulation of structural analysis. A novel stress-based formulat... more This paper demonstrates a novel formulation of structural analysis. A novel stress-based formulation of structural analysis for material nonlinear problems was proposed in earlier work. In this paper, this methodology is further extended for 3D finite element analysis. The approach avoids use of elastic moduli as the material input in the analysis procedure. It utilizes the whole stress-strain curve of the material. It can be shown that this analysis procedure solved the nonlinear or plasticity problem with relative ease. This paper solves a uniaxial bar, in which the results are compared with the solutions of Green-Lagrange strain and Piola-Kirchhoff stresses. The uniaxial bar is also solved by a regression model in the ‘scikit-learn’ module in Python. The second problem solved is of a beam in pure bending for which the energy release rate is measured. For the beam in pure bending, the bending moment carrying capacity of the beam section is evaluated by this methodology as the crack propagates through the depth of the beam. It can be shown that the methodology is very simple, accurate, and clear in its physical steps.
This article proposes analysis procedure of structural mechanic’s problem as integral formulation... more This article proposes analysis procedure of structural mechanic’s problem as integral formulation. The methodology is novel which can be suitable applied for finding the solution of engineering problems with required accuracy either it is linear or nonlinear range (plastic range) of the material behaviour. This methodology, which was proposed as stress-based analysis procedure, exploits the unfolded part of the structural analysis problems which were not so easy to solve such as geometric and material nonlinearity together with simple integration technique [11]. In fracture mechanics, it has already unfolded the misery of physically exploiting plastic behaviour of structures before the start of crack for elastic materials [13]. The formulation is integral formulation rather than differential formulation in which whole stress –strain behaviour is utilised in the analysis procedure by using neural network as regression tool. In this article, one dimensional problem of uniaxial bar, be...
In this article, shape functions for higher-order shear deformation beam theory are derived. For ... more In this article, shape functions for higher-order shear deformation beam theory are derived. For the two nodded beam element, transverse deflection is assumed as cubic polynomial. By using equations of equilibrium of high-order theory that are already derived by J. N. Reddy in 1997, equation for slope of high- order theory is found. Finally with the boundary conditions of beam element and assumed kinematics of high-order theory, shape functions are derived.
This study covers optimization of I-sectional flange beams. Scope of this study is limited to med... more This study covers optimization of I-sectional flange beams. Scope of this study is limited to medium weight flange beams of Table 1 of IS 808:1983 but it can be further extended for the other sections of this code. Best possible geometric shape of the cross-section is found for maximum performance of the beam with minimum material consumption. All possible loading conditions are considered in the study for which a beam in flexure undergoes in its life. ANSYS software program is used for the analysis and optimizing the sections. It is found that sections MB 125, MB 300 and MB 400 of Table 1 of IS 808 are not the optimum sections but other alternative of these crosssections is available which within the same material consumption performs better than these sections of IS code.
Human population is constantly exposed to health risks by exposure to chemicals belonging to vari... more Human population is constantly exposed to health risks by exposure to chemicals belonging to various classes such as pesticides, pollutants and chemicals used in agriculture, food industries etc. It is important to keep use of such chemicals under continuous observation and their effects must be re-evaluated in the light of changing conditions of use and new scientific information (Council directive 89/107/EEC). Major part of my thesis is focused on investigating toxic effects and mechanisms of action of one such environmental pollutant, glyphosate, a non-selective herbicide. In this thesis, mechanistic toxicology of sodium benzoate (SB), a common food preservative, has also been investigated. I have used zebrafish vertebrate animal model for toxicity studies included in my thesis and therefore I have also established a zebrafish research lab at IITH. Glyphosate is a non-selective herbicide. Results included in my thesis indicate significant acute toxicity in zebrafish embryos expos...
Biochemical and Biophysical Research Communications, 2019
Glyphosate, an herbicide used worldwide, has emerged as a pollutant. However, its toxic effects a... more Glyphosate, an herbicide used worldwide, has emerged as a pollutant. However, its toxic effects are debated by regulatory authorities. Therefore, it is essential to keep the use of such chemicals under continuous observation, and their effects must be re-evaluated. We used zebrafish embryos to evaluate the toxic effects of glyphosate and its mechanisms. We found that glyphosate induced significant toxicity in a time and concentration-dependent manner. We observed an LD 50 of 66.04 ± 4.6 mg/mL after 48 h of exposure. Glyphosate significantly reduced the heartbeat in a time and concentration-dependent manner indicating cardiotoxicity. Selective downregulation of Cacana1C (L-type calcium channel) and ryr2a (Ryanodine receptor) genes along with selective upregulation of hspb11 (heat shock protein) gene was observed upon exposure to glyphosate indicating alterations in the calcium signaling. A reduction in the nitric oxide (NO) generation was also observed in the zebrafish embryos upon exposure to glyphosate. Our results indicate that glyphosate induces significant toxicity including cardiotoxicity in zebrafish embryos in a time and concentration-dependent manner. Further, cardiotoxicity may be due to changes in calcium and NO signaling.
Voltage-gated calcium channels (VGCCs) are the predominant source of calcium influx in the heart ... more Voltage-gated calcium channels (VGCCs) are the predominant source of calcium influx in the heart leading to calcium-induced calcium release and ultimately excitation-contraction coupling. In the heart, VGCCs are modulated by the β-adrenergic signaling. Signaling through β-adrenergic receptors (βARs) and modulation of VGCCs by β-adrenergic signaling in the heart are critical signaling and changes to these have been significantly implicated in heart failure. However, data related to calcium channel dysfunction in heart failure is divergent and contradictory ranging from reduced function to no change in the calcium current. Many recent studies have highlighted the importance of functional and spatial microdomains in the heart and that may be the key to answer several puzzling questions. In this review, we have briefly discussed the types of VGCCs found in heart tissues, their structure, and significance in the normal and pathological condition of the heart. More importantly, we have re...
For the assessment of cardiac function, heartbeat represents one key parameter. Current methods o... more For the assessment of cardiac function, heartbeat represents one key parameter. Current methods of heartbeat measurements in the zebrafish larvae usually require larval immobilization, fluorescent transgenic strains and a confocal microscope, costly commercial software for analysis, or strong programming skills if the software is open-source. Here, we present a simple yet powerful method of heartbeat analysis using untethered, unlabeled zebrafish larva using ImageJ (open-source software), which does not require programming skills. We named it as ZebraPace for Zebrafish Precise Algorithm for Cardiac-rhythm Estimation. ZebraPace works directly with AVI videos and requires no image processing steps. ZebraPace uses pixel intensity change in a grayscale video to count the number of beats. We have validated the ZebraPace method by pharmacological alterations of the heartbeat in zebrafish larvae of 48 and 72 hpf stages. We have also determined beat-to-beat interval, which relates to rhythm...
Biochemical and biophysical research communications, Jul 20, 2018
Sodium benzoate (SB) is a common food preservative. Its FDA described safety limit is 1000 ppm. L... more Sodium benzoate (SB) is a common food preservative. Its FDA described safety limit is 1000 ppm. Lately, increased use of SB has prompted investigations regarding its effects on biological systems. Data regarding toxicity of SB is divergent and controversial with studies reporting both harmful and beneficial effects. Therefore, we did a systematic dose dependent toxicity study of SB using zebrafish vertebrate animal model. We also investigated oxidative stress and anxiety-like behaviour in zebrafish larva treated with SB. Our results indicate that SB induced developmental (delayed hatching), morphological (pericardial edema, yolk sac edema and tail bending), biochemical (oxidative stress) and behavioural (anxiety-like behaviour) abnormalities in developing zebrafish larva. LC of SB induced toxicity was approximately 400 ppm after 48 h of SB exposure. Our study strongly supports its harmful effects on vertebrates at increasing doses. Thus, we suggest caution in the excessive use of th...
The article demonstrates a novel approach for material nonlinear analysis. This analysis procedur... more The article demonstrates a novel approach for material nonlinear analysis. This analysis procedure eliminates tedious and lengthy step by step incremental and then iterative procedure adopted classically and gives direct results in the linear as well as in nonlinear range of the material behavior. It is found that the methodology is very suitable to apply for the brittle material such as concrete and composite materials. One dimensional problem of a simple bar is solved to formulate fundamental procedure and basics of the method. Another two dimensional problem of beam bending is solved for further strengthening the method. It is found that it is an excellent computational procedure adopted so far for material nonlinear analysis which gives very accurate results, easy to adopt and simple in calculations. The method not only eliminates linearity assumptions in its derivations and calculations but also eliminates all types of possibility of errors in the analysis procedure.
This article demonstrates a new approach for nonlinear finite element analysis. The methodology i... more This article demonstrates a new approach for nonlinear finite element analysis. The methodology is very suitable and gives very accurate results in linear as well as in nonlinear range of the material behavior. Proposed methodology can be regarded as stress based finite element analysis as it is required to define the stress distribution within the structural body with structural idealization and modelling assumptions. The methodology eliminates the lengthy and tedious procedure of step by step and then iterative procedure adopted classically for nonlinear analysis problems. One dimensional problem of a simple bar loaded axially is solved to formulate the basic principles. Two dimensional problem of a cantilever beam bending and a torsional problem are solved for further demonstrating and strengthening the method. Results of torsional problem are verified with experimental results. The method is applicable for material nonlinear analysis only.
This paper demonstrates a novel formulation of structural analysis. A novel stress-based formulat... more This paper demonstrates a novel formulation of structural analysis. A novel stress-based formulation of structural analysis for material nonlinear problems was proposed in earlier work. In this paper, this methodology is further extended for 3D finite element analysis. The approach avoids use of elastic moduli as the material input in the analysis procedure. It utilizes the whole stress-strain curve of the material. It can be shown that this analysis procedure solved the nonlinear or plasticity problem with relative ease. This paper solves a uniaxial bar, in which the results are compared with the solutions of Green-Lagrange strain and Piola-Kirchhoff stresses. The uniaxial bar is also solved by a regression model in the ‘scikit-learn’ module in Python. The second problem solved is of a beam in pure bending for which the energy release rate is measured. For the beam in pure bending, the bending moment carrying capacity of the beam section is evaluated by this methodology as the crack propagates through the depth of the beam. It can be shown that the methodology is very simple, accurate, and clear in its physical steps.
This article proposes analysis procedure of structural mechanic’s problem as integral formulation... more This article proposes analysis procedure of structural mechanic’s problem as integral formulation. The methodology is novel which can be suitable applied for finding the solution of engineering problems with required accuracy either it is linear or nonlinear range (plastic range) of the material behaviour. This methodology, which was proposed as stress-based analysis procedure, exploits the unfolded part of the structural analysis problems which were not so easy to solve such as geometric and material nonlinearity together with simple integration technique [11]. In fracture mechanics, it has already unfolded the misery of physically exploiting plastic behaviour of structures before the start of crack for elastic materials [13]. The formulation is integral formulation rather than differential formulation in which whole stress –strain behaviour is utilised in the analysis procedure by using neural network as regression tool. In this article, one dimensional problem of uniaxial bar, be...
In this article, shape functions for higher-order shear deformation beam theory are derived. For ... more In this article, shape functions for higher-order shear deformation beam theory are derived. For the two nodded beam element, transverse deflection is assumed as cubic polynomial. By using equations of equilibrium of high-order theory that are already derived by J. N. Reddy in 1997, equation for slope of high- order theory is found. Finally with the boundary conditions of beam element and assumed kinematics of high-order theory, shape functions are derived.
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Papers by Himanshu Gaur