Inhibition of corrosion of mild steel in simulated oil well water by an aqueous extract of Andrographis paniculata

An aqueous extract of Andrographis paniculata has been used as corrosion inhibitor, in controlling corrosion of mild steel in simulated oil well water (SOWW). Weight loss method reveals that 10 mL of the extract offers 94% inhibition efficiency to mild steel immersed in simulated oil well water (SOWW). The mechanistic aspects of corrosion inhibition have been investigated by electrochemical studies such as polarization study and AC impedance spectra. Polarisation study reveals that the inhibitor system controls the cathodic reaction predominantly as revealed by the shift of the corrosion potential to the cathodic side in presence of the inhibitor system. The corrosion protective nature of the inhibitor is confirmed by the increase in the linear polarization resistance value and decrease in the corrosion current value. The formation of a protective film on the metal surface is confirmed by the AC impedance spectra. This is confirmed by the fact that there is increase in charge transfer resistance value and decrease in double layer capacitance value. The adsorption of the inhibitor molecule obeys Langmuir adsorption isotherm. The protective film has been analyzed FTIR spectra. It confirms that the inhibitor has coordinated with ferrous ion the metal surface through the polar atoms of the inhibitor molecule. The surface morphology of the protective film has been investigated by SEM and AFM. It is observed that in presence of inhibitor the surface of the corroded metal becomes smoother. The Vickers hardness of the metal surface before experimentation and after experimentation has been measured. It is observed that the surface becomes harder in presence of inhibitor than in the absence of inhibitor under the influence of corrosive medium, namely simulated oil well water. The findings have potential application in petroleum industry. The inhibitor extract can be added along with the simulated oil well water in the pipelines made of mild steel

Dynamics of Cell Area and Force during Spreading

AbstractExperiments on human pulmonary artery endothelial cells are presented to show that cell area and the force exerted on a substrate increase simultaneously, but with different rates during spreading; rapid-force increase systematically occurred several minutes past initial spreading. We examine this theoretically and present three complementary mechanisms that may accompany the development of lamellar stress during spreading and underlie the observed behavior. These include: 1), the dynamics of cytoskeleton assembly at the cell basis; 2), the strengthening of acto-myosin forces in response to the generated lamellar stresses; and 3), the passive strain-stiffening of the cytoskeleton

Inhibition of corrosion of mild steel in simulated oil well water by an aqueous extract of Andrographis paniculata

452-460An aqueous extract of Andrographis paniculata has been used as corrosion inhibitor, in controlling corrosion of mild steel in simulated oil well water (SOWW). Weight loss method reveals that 10 mL of the extract offers 94% inhibition efficiency to mild steel immersed in simulated oil well water (SOWW). The mechanistic aspects of corrosion inhibition have been investigated by electrochemical studies such as polarization study and AC impedance spectra. Polarisation study reveals that the inhibitor system controls the cathodic reaction predominantly as revealed by the shift of the corrosion potential to the cathodic side in presence of the inhibitor system. The corrosion protective nature of the inhibitor is confirmed by the increase in the linear polarization resistance value and decrease in the corrosion current value. The formation of a protective film on the metal surface is confirmed by the AC impedance spectra. This is confirmed by the fact that there is increase in charge transfer resistance value and decrease in double layer capacitance value. The adsorption of the inhibitor molecule obeys Langmuir adsorption isotherm. The protective film has been analyzed FTIR spectra. It confirms that the inhibitor has coordinated with ferrous ion the metal surface through the polar atoms of the inhibitor molecule. The surface morphology of the protective film has been investigated by SEM and AFM. It is observed that in presence of inhibitor the surface of the corroded metal becomes smoother. The Vickers hardness of the metal surface before experimentation and after experimentation has been measured. It is observed that the surface becomes harder in presence of inhibitor than in the absence of inhibitor under the influence of corrosive medium, namely simulated oil well water. The findings have potential application in petroleum industry. The inhibitor extract can be added along with the simulated oil well water in the pipelines made of mild steel

JunB Mediates Basal- and TGFβ1-Induced Smooth Muscle Cell Contractility

Smooth muscle contraction is a dynamic process driven by acto-myosin interactions that are controlled by multiple regulatory proteins. Our studies have shown that members of the AP-1 transcription factor family control discrete behaviors of smooth muscle cells (SMC) such as growth, migration and fibrosis. However, the role of AP-1 in regulation of smooth muscle contractility is incompletely understood. In this study we show that the AP-1 family member JunB regulates contractility in visceral SMC by altering actin polymerization and myosin light chain phosphorylation. JunB levels are robustly upregulated downstream of transforming growth factor beta-1 (TGFβ1), a known inducer of SMC contractility. RNAi-mediated silencing of JunB in primary human bladder SMC (pBSMC) inhibited cell contractility under both basal and TGFβ1-stimulated conditions, as determined using gel contraction and traction force microscopy assays. JunB knockdown did not alter expression of the contractile proteins α-SMA, calponin or SM22α. However, JunB silencing decreased levels of Rho kinase (ROCK) and myosin light chain (MLC20). Moreover, JunB silencing attenuated phosphorylation of the MLC20 regulatory phosphatase subunit MYPT1 and the actin severing protein cofilin. Consistent with these changes, cells in which JunB was knocked down showed a reduction in the F:G actin ratio in response to TGFβ1. Together these findings demonstrate a novel function for JunB in regulating visceral smooth muscle cell contractility through effects on both myosin and the actin cytoskeleton

Role of Melatonin in Directing Plant Physiology

Melatonin (MT), a naturally occurring compound, is found in various species worldwide. In 1958, it was first identified in the pineal gland of dairy cows. MT is an "old friend" but a "new compound" for plant biology. It brings experts and research minds from the broad field of plant sciences due to its considerable influence on plant systems. The MT production process in plants and animals is distinct, where it has been expressed explicitly in chloroplasts and mitochondria in plants. Tryptophan acts as the precursor for the formation of phyto-melatonin, along with intermediates including tryptamine, serotonin, N-acetyl serotonin, and 5-methoxy tryptamine. It plays a vital role in growth phases such as the seed germination and seedling growth of crop plants. MT significantly impacts the gas exchange, thereby improving physio-chemical functions in plant systems. During stress, the excessive generation and accumulation of reactive oxygen species (ROS) causes protein oxidation, lipid peroxidation, nucleic acid damage, and enzyme inhibition. Because it directly acts as an antioxidant compound, it awakens the plant antioxidant defense system during stress and reduces the production of ROS, which results in decreasing cellular oxidative damage. MT can enhance plant growth and development in response to various abiotic stresses such as drought, salinity, high temperature, flooding, and heavy metals by regulating the antioxidant mechanism of plants. However, these reactions differ significantly from crop to crop and are based on the level and kind of stress. The role of MT in the physiological functions of plants towards plant growth and development, tolerance towards various abiotic stresses, and approaches for enhancing the endogenous MT in plant systems are broadly reviewed and it is suggested that MT is a steering compound in directing major physiological functions of plants under the changing climate in future

An economic evaluation of implementing a decentralized dengue screening intervention under the National Vector Borne Disease Control Programme in Tamil Nadu, South India.

BACKGROUND Lack of effective early screening is a major obstacle for reducing the fatality rate and disease burden of dengue. In light of this, the government of Tamil Nadu has adopted a decentralized dengue screening strategy at the primary healthcare (PHC) facilities using blood platelet count. Our objective was to determine the cost-effectiveness of a decentralized screening strategy for dengue at PHC facilities compared with the current strategy at the tertiary health facility (THC) level. METHODS Decision tree analysis followed a hypothetical cohort of 1000 suspected dengue cases entering the model. The cost-effectiveness analysis was performed at a 3% discount rate for the proposed and current strategy. The outcomes are expressed in incremental cost-effectiveness ratios (ICERs) per quality-adjusted life years gained. One-way sensitivity analysis and probabilistic sensitivity analysis were done to check the uncertainty in the outcome. RESULTS The proposed strategy was found to be cost-saving and ICER was estimated to be -41 197. PSA showed that the proposed strategy had a 0.84 probability of being an economically dominant strategy. CONCLUSIONS The proposed strategy is cost-saving, however, it is recommended to consider optimal population coverage, costs to economic human resources and collateral benefits of equipment

Economic evaluation of implementing a rapid point-of-care screening test for the identification of hepatitis C virus under National Viral Hepatitis Control Programme in Tamil Nadu, South India

Introduction: Viral hepatitis is a crucial public health problem in India. Hepatitis C virus (HCV) elimination is a national priority and a key strategy has been adopted to strengthen the HCV diagnostics services to ensure early and accurate diagnosis. Methods: To conduct an economic evaluation of implementing a rapid point-of-care screening test for the identification of HCV among the selected key population under the National Viral Hepatitis Control Programme in Tamil Nadu, South India. Economic evaluation of a point-of-care screening test for HCV diagnosis among the key population attending the primary health care centers. A combination of decision tree and Markov model was developed to estimate cost-effectiveness of point-of-care screening test for HCV diagnosis at the primary health care centers. Total costs, quality-adjusted life years (QALYs) of the intervention and comparator, and incremental cost-effectiveness ratio (ICER) were calculated. The model parameter uncertainties which would influence the cost-effectiveness outcome has been evaluated by one-way sensitivity analysis and probabilistic sensitivity analysis. Results: When compared to the tertiary level diagnostic strategy for HCV, the point-of-care screening for selected key population at primary health care level results in a gain of 57 undiscounted QALYs and 38 discounted QALYs, four undiscounted life years and two discounted life years. The negative ICER of the new strategy indicates that it is less expensive and more effective compared with the current HCV diagnosis strategy. Conclusions: The proposed strategy for HCV diagnosis in the selected key population in Tamil Nadu is dominant and cost-saving compared to the current strategy

Fluidization and Resolidification of the Human Bladder Smooth Muscle Cell in Response to Transient Stretch

Background: Cells resident in certain hollow organs are subjected routinely to large transient stretches, including every adherent cell resident in lungs, heart, great vessels, gut, and bladder. We have shown recently that in response to a transient stretch the adherent eukaryotic cell promptly fluidizes and then gradually resolidifies, but mechanism is not yet understood. Principal Findings: In the isolated human bladder smooth muscle cell, here we applied a 10% transient stretch while measuring cell traction forces, elastic modulus, F-actin imaging and the F-actin/G-actin ratio. Immediately after a transient stretch, F-actin levels and cell stiffness were lower by about 50%, and traction forces were lower by about 70%, both indicative of prompt fluidization. Within 5min, F-actin levels recovered completely, cell stiffness recovered by about 90%, and traction forces recovered by about 60%, all indicative of resolidification. The extent of the fluidization response was uninfluenced by a variety of signaling inhibitors, and, surprisingly, was localized to the unstretch phase of the stretch-unstretch maneuver in a manner suggestive of cytoskeletal catch bonds. When we applied an “unstretch-restretch” (transient compression), rather than a “stretch-unstretch” (transient stretch), the cell did not fluidize and the actin network did not depolymerize. Conclusions: Taken together, these results implicate extremely rapid actin disassembly in the fluidization response, and slow actin reassembly in the resolidification response. In the bladder smooth muscle cell, the fluidization response to transient stretch occurs not through signaling pathways, but rather through release of increased tensile forces that drive acute disassociation of actin

Evaluating the anti-amoebic activity of putative chemotherapeutic targets and their metal nanoparticle conjugates against Naegleria Fowleri

Naegleria fowleri infects the central nervous system and causes primary amoebic meningoencephalitis (PAM). These brain-eating amoebae invade the nervous system via the nose when contaminated water is deeply inhaled. Subsequently, they invade into the brain tissue; causing severe haemorrhage and inflammation, resulting in widespread brain tissue destruction. Delayed diagnosis with inappropriate treatment available and the devastating nature of the disease results in a mortality rate of 98%. In this study, three groups of compounds were used: antifungals (amphotericin B, nystatin and fluconazole), CNS drugs (phenytoin, phenobarbitone and diazepam) and natural products (cinnamic acid, oleic acid, hesperidin and naringin). The compounds were conjugated with metal nanoparticles and their efficacy against N. fowleri was evaluated. The conjugated compounds were characterized for their physical properties using various techniques. Following that, their anti-amoebic potential against N. fowleri was assessed. The metal nanoparticles-conjugated compounds showed enhanced anti-amoebic activity and reduced host cell cytotoxicity. hesperidin appeared to exhibit the most potent activity as compared to all other compounds. Transcriptomic analysis identified genes that were differentially regulated in cells treated with silver nanoparticles-conjugated hesperidin. These results provide new insights towards the development of therapeutic targets against N. fowleri-associated PAM by repurposing existing drugs and identifying new natural products-based targets