The impact of a chemical reaction on the heat and mass transfer mechanisms in a dissipative and radiative nanofluid flow over a nonlinear stretching sheet.

This paper presents a numerical investigation of the flow of a non-Newtonian tangent hyperbolic nanofluid over a nonlinearly stretched surface, taking into account factors such as thermal radiation, prescribed surface temperature, and a chemical reaction mechanism. Furthermore, the analysis includes the consideration of both viscous dissipation and the influence of a magnetic field within a Darcy porous medium. A mathematical framework for addressing the issue, rooted in the principles of conserving momentum, energy, and mass. The MATHEMATICA tools were employed to apply the shooting technique in order to solve the modeled equations describing the temperature, velocity, and concentration fields of the proposed physical system. Graphs are used to illustrate how certain key parameters affect the profiles of concentration, velocity, and temperature. Data tables are utilized to display information pertaining to the local Nusselt number, local Sherwood number, and local skin friction coefficient. The present results have been confirmed through a comparison with previously published findings. This research holds significant importance as it focuses on the extensive utilization of tangent hyperbolic nanofluids in cooling electronic components that produce substantial heat during their operation. The observed pattern indicates that as the local Weisbsenberg number, magnetic number, local porous parameter, and power law index increase, there is a reduction in the boundary layer thickness. Conversely, in the instances of concentration and temperature distributions, an escalation in these parameters leads to an expansion of the boundary layer thickness.

A comparative study on the rheological properties of upper convected Maxwell fluid along a permeable stretched sheet.

The objective of this paper is to examine the flow of a non-Newtonian Maxwell fluid induced by a permeable stretching sheet in motion within a porous medium. The research incorporates the Cattaneo-Christov heat flux model to study the heat transfer process. The utilization of the Cattaneo-Christov heat flux approach becomes relevant in scenarios involving materials with high thermal conductivity or during short time intervals. Consequently, the current investigation holds significant importance. It is assumed that the viscosity of the Maxwell fluid changes exponentially as the temperature changes. The modeling of the physical phenomena being investigated takes into account the effects of a magnetic field, thermal radiation, velocity, and thermal slip conditions. In this study, the viscous dissipation phenomenon is taken into account because it can have notable impacts on the temperature and viscosity of the fluid, and is known to play a crucial role in fluid flow phenomena. The equations developed to model fluid flow are transformed into nonlinear ordinary differential equations through the use of appropriate similarity transformations. The focus of the research revolves around investigating the numerical solution of ordinary differential equations accompanied by boundary conditions using the shooting technique. The findings are then showcased via tables and graphs and scrutinized in order to arrive at conclusions. Furthermore, the precision of the present findings was evaluated by contrasting the heat transfer rate with outcomes that were previously published. Based on the obtained outcomes, it can be concluded that both the Eckert number and thermal radiation have a comparable enhancing influence, whereas the thermal relaxation parameter and thermal slip parameter exhibit opposing effects.

MHD dissipative Powell-Eyring fluid flow due to a stretching sheet with convective boundary conditions and slip velocity.

The novelty and motivation of this research can be emphasized by examining how the heat transfer mechanism of a non-Newtonian Powell-Eyring fluid, which flows because of a stretched sheet, is affected by factors like viscous dissipation, the slip velocity phenomenon, and Joule heating. In addition, the investigation delves into the heat transfer behavior of the fluid flow when it comes into contact with a convectively heated stretched surface that is influenced by varying fluid properties. This analysis also takes into account the influence of changing fluid characteristics and the presence of magnetic field. The numerical solutions of modelled equations that governing the problem are detected using the shooting technique. Also, in order to confirm the validity of the present investigation, a proper comparison with certain published works as a particular case of the present model is presented, and a perfect agreement is noted. With the use of diagrams and tables, the flow problem's effective parameters are thoroughly discussed. Likewise, through a tabular representation, the values of the local Nusselt number and the skin-friction coefficient are computed and analyzed. Many significant conclusions can be drawn from numerical results. Most importantly, the local Nusselt number rises monotonically with both the surface convection parameter and the slip velocity parameter, but the local skin-friction coefficient has the opposite trend. The results indicate that the nanofluid temperature is enhanced by factors such as the surface convection parameter, magnetic field, and viscous dissipation. On the other hand, the slip velocity phenomenon leads to the opposite effect.

Cardioprotective Effects of Octreotide against Sepsis-Induced Cardiotoxicity in Mice.

Sepsis is a systemic inflammatory consequence resulting from microbial infection, assessed as a worldwide healthcare issue. Sepsis can result in multiorgan dysfunction, including cardiac, renal, hepatic, and cerebral dysfunction. Cardiotoxicity can occur in humans and rodents during sepsis, leading to increased mortality. The current study aims to explore the possible cardioprotective effects of octreotide during sepsis-induced cardiotoxicity. This study was done with a total of forty male albino Swiss mice, aged 8-12 weeks and weighing 25-30 gm. These animals had free access to food and water. After two weeks of adaptation, mice were divided into four groups (n=10): 1) Normal group: healthy mice; 2) CLP group: mice underwent CLP operation; 3) Vehicle group: mice received DMSO. 4) Octreotide group: mice received octreotide (10 mg/kg) subcutaneously in 2 divided doses for 5 consecutive days. All groups underwent CLP operation on the 4th day, then sacrificed on the 5th day then blood, and tissue sampling was done. The Octreotide group demonstrated a significant (P<0.05) decrease in the myocardial levels of cardiac troponin-I as compared to the CLP group. Furthermore, the octreotide group demonstrated a significant (P<0.05) decrease in the serum level of inflammatory cytokines (TNF-α, IL-6, & IL-1ß) as compared to the CLP group. Additionally, the octreotide group showed a significant (P<0.05) elevation in the myocardial activity of SOD and a reduction in MDA level compared to the CLP group. Histologically, all mice in the CLP group showed a significant (P<0.05) cardiac tissue injury, while the octreotide groups showed a significant (P<0.05) reduced level of cardiac tissue injury. The results of the present study revealed that octreotide attenuates sepsis-induced cardiotoxicity through different protective effects; they include the anti-inflammatory effect through their ability to decrease serum levels of inflammatory cytokines (TNF-α, IL-1ß, and IL-6). Also, the anti-oxidant effect through their ability to decrease myocardial levels of MDA and increase the myocardial activity of SOD. Additionally, the direct cardiac protective effect through the lower level of cardiac troponin- I and the reduction of histopathological changes during sepsis-induced cardiotoxicity.

Automated gesture tracking in head-fixed mice.

BACKGROUND: The preparation consisting of a head-fixed mouse on a spherical or cylindrical treadmill offers unique advantages in a variety of experimental contexts. Head fixation provides the mechanical stability necessary for optical and electrophysiological recordings and stimulation. Additionally, it can be combined with virtual environments such as T-mazes, enabling these types of recording during diverse behaviors. NEW METHOD: In this paper we present a low-cost, easy-to-build acquisition system, along with scalable computational methods to quantitatively measure behavior (locomotion and paws, whiskers, and tail motion patterns) in head-fixed mice locomoting on cylindrical or spherical treadmills. EXISTING METHODS: Several custom supervised and unsupervised methods have been developed for measuring behavior in mice. However, to date there is no low-cost, turn-key, general-purpose, and scalable system for acquiring and quantifying behavior in mice. RESULTS: We benchmark our algorithms against ground truth data generated either by manual labeling or by simpler methods of feature extraction. We demonstrate that our algorithms achieve good performance, both in supervised and unsupervised settings. CONCLUSIONS: We present a low-cost suite of tools for behavioral quantification, which serve as valuable complements to recording and stimulation technologies being developed for the head-fixed mouse preparation.

Numerical technique of blood flow through catheterized arteries with overlapping stenosis.

This study is concerned with the surgical technique for the injection of a catheter through arteries with overlapping stenosis in the presence of externally applied magnetic field and Hall currents influences. The nature of blood is analyzed mathematically by considering it as a micropolar fluid. The analysis is carried out for an artery with a mild stenosis. The governing equations with the corresponding boundary conditions solved numerically using Crank-Nicolson implicit finite difference scheme. The numerical technique give excellent agreement for axial velocity of the fluid, the circumferential microrotation, the wall shear stress distribution and the contour plots of stream lines. The obtained results show that the value of axial velocity is higher for a Newtonian fluid than that for a micropolar fluid model, the effect of suitable moving magnetic field (Hall currents influences) accelerates the speed of blood, the size of trapped bolus for the stream lines decrease if the spinning movement of the fluid molecules have considerable value regardless of small or large size of the fluid molecules and the flow of fluid is better with increasing the Hall current effect and the size of trapping bolus increase clearly by increasing the maximum height of stenosis where the fluid moves as a bulk.

Blockade of BFA-mediated apoptosis in macrophages by the HIV-1 Nef protein.

HIV-1 Nef protein has key roles at almost all stages of the viral life cycle. We assessed the role of Nef and of the translation elongation factor eEF1A in primary human macrophages. Nuclear retention experiments and inhibition of the exportin-t (Exp-t) pathway suggested that cytoplasmic relocalization of eEF1A, mediated by Exp-t occurs in Nef-treated monocyte-derived macrophages (MDMs). We observed the presence of tRNA in the Nef/eEF1A complexes. Nucleocytoplasmic relocalization of the Nef/eEF1A complexes prevented stress-induced apoptosis of MDMs treated with brefeldin A. Blockade of stress-induced apoptosis of MDMs treated with HIV-1 Nef resulted from enhanced nucleocytoplasmic transport of eEF1A with decreased release of mitochondrial cytochrome c, and from increased tRNA binding to cytochrome c, ultimately leading to an inhibition of caspase activation. Our results indicate that HIV-1 Nef, through the nucleocytoplasmic relocalization of eEF1A and tRNAs, enhances resistance to stress-induced apoptosis in primary human macrophages.

Molecular Understanding of HIV-1 Latency.

The introduction of highly active antiretroviral therapy (HAART) has been an important breakthrough in the treatment of HIV-1 infection and has also a powerful tool to upset the equilibrium of viral production and HIV-1 pathogenesis. Despite the advent of potent combinations of this therapy, the long-lived HIV-1 reservoirs like cells from monocyte-macrophage lineage and resting memory CD4+ T cells which are established early during primary infection constitute a major obstacle to virus eradication. Further HAART interruption leads to immediate rebound viremia from latent reservoirs. This paper focuses on the essentials of the molecular mechanisms for the establishment of HIV-1 latency with special concern to present and future possible treatment strategies to completely purge and target viral persistence in the reservoirs.

Inhibition of ER stress-mediated apoptosis in macrophages by nuclear-cytoplasmic relocalization of eEF1A by the HIV-1 Nef protein.

HIV-1 Nef protein has key roles at almost all stages of the viral life cycle. We assessed the role of the Nef/eEF1A (eukaryotic translation elongation factor 1-alpha) complex in nucleocytoplasmic shuttling in primary human macrophages. Nuclear retention experiments and inhibition of the exportin-t (Exp-t) pathway suggested that cytoplasmic relocalization of eEF1A, mediated by Exp-t, occurs in Nef-treated monocyte-derived macrophages (MDMs). We observed the presence of tRNA in the Nef/eEF1A complexes. Nucleocytoplasmic relocalization of the Nef/eEF1A complexes prevented stress-induced apoptosis of MDMs treated with brefeldin-A. Blockade of stress-induced apoptosis of MDMs treated with HIV-1 Nef resulted from enhanced nucleocytoplasmic transport of eEF1A with decreased release of mitochondrial cytochrome c, and from increased tRNA binding to cytochrome c, ultimately leading to an inhibition of caspase activation. Our results indicate that HIV-1 Nef, through the nucleocytoplasmic relocalization of eEF1A and tRNAs, enhances resistance to stress-induced apoptosis in primary human macrophages.

Effect of GABA and baclofen on gastric mucosal protective factors.

GABA and baclofen (BAC), a GABA-mimetic agent, were investigated for antiulcerogenic activity. Orally administered GABA (100 mg/kg) and BAC (10 mg/kg) showed significant ulcer protection when given either alone for one day or for 4 days, or when given together with aspirin (ASP; 200 mg/kg x 3 days) in their 4 days treatment time in pylorus-ligated rats. Both the drugs showed a tendency to increase acid and decrease peptic output, and increased gastric mucus secretion in terms of total carbohydrate to protein ratio (TC:P) in both the above treatment groups. ASP tended to decrease acid and increase peptic output and significantly decreased TC:P ratio. Both GABA and BAC tended to reverse aspirin-induced effects, though they had little per se effect on TC:P ratio of gastric mucosal glycoproteins except an increase in sialic acid content both after one day or four days treatment. No, per se, effect on cell shedding (DNA and protein content of gastric juice) or cell proliferation (DNA/mg protein) was noted with GABA or BAC but the enhanced cell shedding induced by ASP was attenuated by them. ASP was found to enhance cell proliferation. However, neither of drug showed any effect on cell proliferation when given either alone or in combination with ASP. The antiulcerogenic effect of GABA and BAC may be due to their predominant effects on mucosal defensive factors like enhanced mucin secretion and decreased cell shedding or mucosal damage.

Effect of continuous infusion of GABA and baclofen on gastric secretion in anaesthetised rats.

Continuous infusion of gamma- aminobutyric acid (GABA) and baclofen (BAC) on gastric acid and pepsin secretion in perfused rat stomach showed that GABA (25-100 mg/kg/hr, i.v.) and BAC (1 mg/kg/hr, i.v.) increased the acid output which was blocked by bicuculline (Bicc, 1 mg/kg, i.v.) when given 30 min before their infusion. However, lower dose of GABA (5 mg/kg/hr) and hig her doses of BAC (5 or 10 mg/kg/hr) did not show any significant effect on acid secretion. GABA (5 and 25 mg/kg/hr) inhibited peptic output and again Bicc in the above dose inhibited the inhibitory effect of 25 mg/kg/hr of GABA on peptic output. The result indicate dichotomy on the effects of GABA on acid and pepsin secretion. As both the effects were blocked by Bicc, involvement of GABAA receptor may be a possibility. The antiulcer effect of GABA and BAC could not be due to their effect on gastric acid secretion, but may be due to inhibition of pepsin secretion by GABA or effects of GABA or BAC on mucosal defensive factors.

Anti-ulcerogenic activity of GABA and GABA mimetic agents in rats.

To elucidate the involvement of peripheral gamma- aminobutyric acid (GABA) and some GABA-mimetic agents in different models of gastric and duodenal ulcerations in rats and guinea pigs, effects of GABA, baclofen (GABAB agonist), diazepam, gamma-butyrolactone (GABA receptor agonist), sodium valproate, isoniazid (GABA-T inhibitor) and glycine (an inhibitory neurotransmitter), given po or ip were studied. All the drugs significantly reduced the ulcer index, incidence and number of ulcer in various models of gastric ulcers except glycine which failed to protect in reserpine-induced ulcers in rats. None of the drugs, except diazepam, had any protective effect on histamine-induced gastric ulcers in guinea pigs. Similarly, no protection was observed by any drug against cysteamine-induced duodenal ulcers in rats, while sodium valproate, isoniazid and glycine significantly decreased number of ulcers against histamine-induced duodenal ulcer in guinea pigs. The results suggest that GABA and GABA-mimetic agents, and glycine, an inhibitory neurotransmitter, afforded protection against some experimental models of peptic ulcer in rats. The effects appear to be due to their inhibitory effect on mucosal defensive factors.

Effect of piracetam, a nootropic agent, on experimental gastric ulcers in rat.

Piracetam, used clinically for cognitive disorders, was found to have significant anti-ulcerogenic activity against immobilization stress- and aspirin-induced gastric ulcers in rats. The anti-ulcer effect of piracetam was exerted by augmentation of mucosal resistance. This was indicated by the significant attenuation of the decrease in total carbohydrate: protein ratio induced by aspirin. It also reversed the marked increase in gastric juice protein and DNA induced by aspirin, indicating that piracetam attenuated the augmented mucosal cell exfoliation induced by the ulcerogen. The drug also increased gastric mucosal serotonin concentrations. Piracetam, thus appears to have a profile of activity associated with cytoprotective agents.