Liquefaction Potential Assessment of Brahmaputra Sand Based on Regular and Irregular Excitations Using Stress-Controlled Cyclic Triaxial Test

Shiv Shankar Kumar,Arindam Dey,A. Murali Krishna 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.4

The response of saturated soil during earthquakes is governed by many factors such as frequency content, strain, stress, excess pore-water pressure and strength variations within the soil mass. This paper highlights the effect of strains on the stiffness modulus and its degradation at the liquefied condition of cohesionless soil. Cyclic triaxial (CT) tests, in stress-controlled manner, were carried out on saturated sandy soil specimens made at different relative density (Dr = 30% − 90%) and effective stress (σ'c = 50 − 200 kPa). The reconstituted specimens were subjected to regular and irregular stress histories. Representative strong motions with varying PGA were chosen, and the corresponding irregular stress histories were used. Additionally, regular stress histories constituted from different cyclic stress amplitudes were also used. The responses of the saturated specimen were obtained in terms of the excess pore-water pressure generation and strain accumulation with elapsed time. In comparison to the standard frequencyand duration parameters (namely the predominant period and significant durations), it is observed that the responses are more influenced by Arias intensity and specific energy density of the strong motion. Based on the increase in pore-water pressure, reduction in shear modulus and increase in shear strain within the specimens, the complete manifestation of liquefaction is divided in four zones, namely the no liquefaction zone, quasi-liquefaction zone, zone marking the onset of liquefaction and the completely liquefied zone. The criteria for the onset of liquefaction of Brahmaputra sand involving shear strain, peak ground acceleration and cyclic stress ratio are provided.

Nicotine Addiction: Neurobiology and Mechanism

Raj Kumar Tiwari,Vikas Sharma,Ravindra Kumar Pandey,Shiv Shankar Shukla 대한약침학회 2020 Journal of pharmacopuncture Vol.23 No.1

Nicotine, primary component of tobaco produces craving and withdrawal effect both in humans and animals. Nicotine shows a close resemblance to other addictive drugs in molecular, neuroanatomical and pharmacological, particularly the drugs which enhances the cognitive functions. Nicotine mainly shows its action through specific nicotinic acetylcholine receptors located in brain. It stimulates presynaptic acetylcholine receptors thereby enhancing Ach release and metabolism. Dopaminergic system is also stimulated by it, thus increasing the concentration of dopamine in nuclear accumbens. This property of nicotine according to various researchers is responsible for reinforcing behavioral change and dependence of nicotine. Various researchers have also depicted that some non dopaminergic systems are also involved for rewarding effect of nicotinic withdrawal. Neurological systems such as GABAergic, serotonergic, noradrenergic, and brain stem cholinergic may also be involved to mediate the actions of nicotine. Further, the neurobiological pathway to nicotine dependence might perhaps be appropriate to the attachment of nicotine to nicotinic acetylcholine receptors, peruse by stimulation of dopaminergic system and activation of general pharmacological changes that might be responsible for nicotine addiction. It is also suggested that MAO A and B both are restrained by nicotine. This enzyme helps in degradation dopamine, which is mainly responsible for nicotinic actions and dependence. Various questions remain uninsurable to nicotine mechanism and require more research. Also, various genetic methods united with modern instrumental analysis might result for more authentic information for nicotine addiction.

Investigation of Corner Cracks in Continuous Casting Billet Using Thermomechanical Model and Plant Measurements

Aditya Narayan Shiv Shankar Swain,Suvankar Ganguly,Arunava Sengupta,Elanjickal Zachariah Chacko,Swapnil Dhakate,Pankaj Kumar Pandey 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.10

A coupled thermofluidic-mechanical model has been developed to analyse the thermomechanical state of the solidifying shellin a continuously cast steel billet. The computational fluid dynamics (CFD) based solver simulates the three-dimensionalflow field and solidification of molten steel as it flows inside the mould. Finite element method based thermomechanicalmodel is coupled with the CFD model to determine the resultant temperature distribution and stress–strain evolution in thesolidifying strand. The heat transfer at the mould-billet interface is taken into account by the calculation of heat flux using anovel inverse heat transfer algorithm. Temperature measurements made in the industrial billet mould have been used for thepurpose. Plant experiments and observations are correlated with the numerical results to provide quantitative understandingof the complex thermomechanical process during billet casting. Various parametric studies are also undertaken to examinethe effects of casting speed, superheat and heat flux changes on resultant strain and temperature distribution. It is observedthat the accumulated plastic strains exceed the critical strain at the off-corner region thereby indicating the possibility ofcrack formation in this region. Reduction of heat flux can lead to lowering of the strain rate at the corners and offer a viablesolution for reducing corner cracks.

Nicotine Addiction: Neurobiology and Mechanism

Tiwari, Raj Kumar,Sharma, Vikas,Pandey, Ravindra Kumar,Shukla, Shiv Shankar KOREAN PHARMACOPUNCTURE INSTITUTE 2020 Journal of pharmacopuncture Vol.23 No.1

Nicotine, primary component of tobaco produces craving and withdrawal effect both in humans and animals. Nicotine shows a close resemblance to other addictive drugs in molecular, neuroanatomical and pharmacological, particularly the drugs which enhances the cognitive functions. Nicotine mainly shows its action through specific nicotinic acetylcholine receptors located in brain. It stimulates presynaptic acetylcholine receptors thereby enhancing Ach release and metabolism. Dopaminergic system is also stimulated by it, thus increasing the concentration of dopamine in nuclear accumbens. This property of nicotine according to various researchers is responsible for reinforcing behavioral change and dependence of nicotine. Various researchers have also depicted that some non dopaminergic systems are also involved for rewarding effect of nicotinic withdrawal. Neurological systems such as GABAergic, serotonergic, noradrenergic, and brain stem cholinergic may also be involved to mediate the actions of nicotine. Further, the neurobiological pathway to nicotine dependence might perhaps be appropriate to the attachment of nicotine to nicotinic acetylcholine receptors, peruse by stimulation of dopaminergic system and activation of general pharmacological changes that might be responsible for nicotine addiction. It is also suggested that MAO A and B both are restrained by nicotine. This enzyme helps in degradation dopamine, which is mainly responsible for nicotinic actions and dependence. Various questions remain uninsurable to nicotine mechanism and require more research. Also, various genetic methods united with modern instrumental analysis might result for more authentic information for nicotine addiction.

Goosecoid Controls Neuroectoderm Specification via Dual Circuits of Direct Repression and Indirect Stimulation in Xenopus Embryos

Umair, Zobia,Kumar, Vijay,Goutam, Ravi Shankar,Kumar, Shiv,Lee, Unjoo,Kim, Jaebong Korean Society for Molecular and Cellular Biology 2021 Molecules and cells Vol.44 No.10

Spemann organizer is a center of dorsal mesoderm and itself retains the mesoderm character, but it has a stimulatory role for neighboring ectoderm cells in becoming neuroectoderm in gastrula embryos. Goosecoid (Gsc) overexpression in ventral region promotes secondary axis formation including neural tissues, but the role of gsc in neural specification could be indirect. We examined the neural inhibitory and stimulatory roles of gsc in the same cell and neighboring cells contexts. In the animal cap explant system, Gsc overexpression inhibited expression of neural specific genes including foxd4l1.1, zic3, ncam, and neurod. Genome-wide chromatin immunoprecipitation sequencing (ChIP-seq) and promoter analysis of early neural genes of foxd4l1.1 and zic3 were performed to show that the neural inhibitory mode of gsc was direct. Site-directed mutagenesis and serially deleted construct studies of foxd4l1.1 promoter revealed that Gsc directly binds within the foxd4l1.1 promoter to repress its expression. Conjugation assay of animal cap explants was also performed to demonstrate an indirect neural stimulatory role for gsc. The genes for secretory molecules, Chordin and Noggin, were up-regulated in gsc injected cells with the neural fate only achieved in gsc uninjected neighboring cells. These experiments suggested that gsc regulates neuroectoderm formation negatively when expressed in the same cell and positively in neighboring cells via soluble factors. One is a direct suppressive circuit of neural genes in gsc expressing mesoderm cells and the other is an indirect stimulatory circuit for neurogenesis in neighboring ectoderm cells via secreted BMP antagonizers.

Current and Future Molecular Mechanism in Inflammation and Arthritis

Sharma, Vikash,Tiwari, Raj Kumar,Shukla, Shiv Shankar,Pandey, Ravindra Kumar KOREAN PHARMACOPUNCTURE INSTITUTE 2020 Journal of pharmacopuncture Vol.23 No.2

Inflammation is an immune response of the human body but excessive inflammation is taken as a major factor in the development of many diseases including autoimmune disorders, cancer and nerve disorders etc. In this regards the need is to suppress the inflammatory response. Suppression of extra or imperfect inflammatory response is not a big deal provided there is an exact knowledge of particular target in the body. Recent advancements in Pharmacological aspect made the therapy with improved outcomes in number of patients. Anticytokine therapy might be one of the important and novel approaches for inflammation and Arthritis. This can be achieved only when we go through the pathophysiology of expression and identification of mediators. Let's take an example of cytokine like interleukins (IL), chemokines, interferons (INF), tumor necrosis factors (TNF-α), growth factors, and colony stimulating factors) release pathway which is a major signalling protein in inflammatory response. In the present study we have reviewed the recent pharmacological therapeutic advancement, inflammatory mediators, receptors, and major signalling pathways. Such information will not only provide the idea about the mechanism of action of Pharmaceuticals and molecular targets but also it provides a new aspect for drug designing and new corrective approaches in existing clinical medicines. This study will be a source of good information for the researchers working in the area of drug designing and molecular Pharmacology especially in anti-inflammatory and anti arthritic medicines for target based therapy.

Antiarthritic Activity and Inflammatory Mediators Modulation Effect of Traditional Ajmodadi Churna on Arthritis Experimental Model

Sharma Vikash,Shukla Shiv Shankar,Gidwani Bina,Pandey Ravindra Kumar 대한약침학회 2023 Journal of pharmacopuncture Vol.26 No.3

Objectives: The study was designed to evaluate anti-arthritic activity of Ajmodadi Churna (AC) and its effect on Complete freund’s adjuvant (CFA)-induced arthritis in Wistar rats. Methods: Arthritis was induced by injecting 0.2 mL CFA into sub plantar surface of left hind paw. Test sample AC-1 and AC-2, 200 and 400 mg/kg, respectively was given to the animals for 21 consecutive days. The increase in swelling was observed after induction of arthritis. The paw edema was measured on 0, 3, 7, 14 and 21 day using Vernier calliper after the induction of arthritis. The collected blood samples further used for the estimation of red blood cells (RBC), white blood cells (WBC), erythrocytes sedimentation rate (ESR), and hemoglobin (Hb), using hematology analyzer. Serum concentration of IL-6 and TNF-α were also measured using rat ELISA kits. Results: Results showed that a significant reduction in paw edema was observed in AC-2 treated rats. The paw edema was restored on day 21 was 4.48 mm for AC-2, which is near to the control group. The arthritis score in treated rats was found to be considerably lower than in the control group i.e. 0.83 for AC-2 and 1.50 for AC-1. A decrease in levels of RBC and hemoglobin were observed in arthritic rats. Inflammation was significantly reduced and serum levels of IL-6 and TNF-α were lowered after treatment with the test drug. Conclusion: It can be concluded from the study that AC possess significant anti-arthritic activity. Furthermore, this condition was linked to a reduction in abnormal humoral immune responses.

Current and Future Molecular Mechanism in Inflammation and Arthritis

Vikash Sharma,Raj Kumar Tiwari,Shiv Shankar Shukla,Ravindra Kumar Pandey 대한약침학회 2020 Journal of pharmacopuncture Vol.23 No.2

Inflammation is an immune response of the human body but excessive inflammation is taken as a major factor in the development of many diseases including autoimmune disorders, cancer and nerve disorders etc. In this regards the need is to suppress the inflammatory response. Suppression of extra or imperfect inflammatory response is not a big deal provided there is an exact knowledge of particular target in the body. Recent advancements in Pharmacological aspect made the therapy with improved outcomes in number of patients. Anticytokine therapy might be one of the important and novel approaches for inflammation and Arthritis. This can be achieved only when we go through the pathophysiology of expression and identification of mediators. Let’s take an example of cytokine like interleukins (IL), chemokines, interferons (INF), tumor necrosis factors (TNF-α), growth factors, and colony stimulating factors) release pathway which is a major signalling protein in inflammatory response. In the present study we have reviewed the recent pharmacological therapeutic advancement, inflammatory mediators, receptors, and major signalling pathways. Such information will not only provide the idea about the mechanism of action of Pharmaceuticals and molecular targets but also it provides a new aspect for drug designing and new corrective approaches in existing clinical medicines. This study will be a source of good information for the researchers working in the area of drug designing and molecular Pharmacology especially in anti-inflammatory and anti arthritic medicines for target based therapy.