COMPAPRATIVE STUDY OF CURVATURE INDUCED IMPROVEMENT IN MASS TRANSFER AND FOULING

Master'sMASTER OF ENGINEERIN

Dissimilar metal joint quality measurement using infrared thermography: Experimental and Numerical approach for the application to CMT welding

Abstract Joining of dissimilar material has become highly popular research subject in the automobile industry due to the reduced weight and thereby increasing the fuel efficiency. Infrared thermography can be used as a natural tool to measure the temperature near the welding region and correlate the distribution of temperature to the weld quality. In the present work the quality of the dissimilar welded sample is identified using the temperature distribution in the vicinity of the weld pool region. A numerical model for CMT continues welding process has been modeled and simulated for the first time and compared with the experimental measurement

Statistical Approach on Perception of Employees Attainments in the Milieu of Non-Public Organisations

Purpose: The aim of this study is to comprehend the various syndromes that influence the performance of individual employees and other factors that have an impact on employee’s performance.   Theoretical framework: Employees are encouraged by management to help facilitate the transition to the new market scenario. Only a balance between work life and family will enable an individual to have a peaceful and healthy life. Indeed, the two factors mentioned above are important considerations for living standards.   Design/methodology/approach: This paper aims to investigate the factors that influence employee performance in non-public organization’s context. The study involves 145 employees from non-public organizations, 56.55% male and 43.44% female, of ages 27 to 45 years. The participants were selected at random from well-known non-public organizations. This study employed a descriptive-quantitative research design.   Findings: The findings show that job-related training, working conditions, family background, workload, and digital knowledge all have a significant impact on employees’ performance.   Research, Practical & Social implications: This study considers job-oriented training, working conditions, work load, employee’s family back ground and their digital knowledge to measure employee’s performance. However clear communication,defining roles,trust leadership and and other variables could also be considered by future researchers on this study.   Originality/value: Using statistical Modelling in understanding Perceptions on employee’s performance was hardly adopted in these types of studies and other variables could also be considered by future researchers on this study

Salvinorin A Regulates Dopamine Transporter Function Via A Kappa Opioid Receptor and ERK1/2-Dependent Mechanism

Salvinorin A (SalA), a selective κ-opioid receptor (KOR) agonist, produces dysphoria and pro-depressant like effects. These actions have been attributed to inhibition of striatal dopamine release. The dopamine transporter (DAT) regulates dopamine transmission via uptake of released neurotransmitter. KORs are apposed to DAT in dopamine nerve terminals suggesting an additional target by which SalA modulates dopamine transmission. SalA produced a concentration-dependent, nor-binaltorphimine (BNI)- and pertussis toxin-sensitive increase of ASP+ accumulation in EM4 cells coexpressing myc-KOR and YFP-DAT, using live cell imaging and the fluorescent monoamine transporter substrate, trans 4-(4-(dimethylamino)-styryl)-N-methylpyridinium) (ASP+). Other KOR agonists also increased DAT activity that was abolished by BNI pretreatment. While SalA increased DAT activity, SalA treatment decreased serotonin transporter (SERT) activity and had no effect on norepinephrine transporter (NET) activity. In striatum, SalA increased the Vmax for DAT mediated DA transport and DAT surface expression. SalA up-regulation of DAT function is mediated by KOR activation and the KOR-linked extracellular signal regulated kinase-½ (ERK1/2) pathway. Co-immunoprecipitation and BRET studies revealed that DAT and KOR exist in a complex. In live cells, DAT and KOR exhibited robust FRET signals under basal conditions. SalA exposure caused a rapid and significant increase of the FRET signal. This suggests that the formation of KOR and DAT complexes is promoted in response to KOR activation. Together, these data suggest that enhanced DA transport and decreased DA release resulting in decreased dopamine signaling may contribute to the dysphoric and pro-depressant like effects of SalA and other KOR agonists

Le rôle des forces actives aux interfaces cellule-cellule et cellule-substrat dans l'organisation du tissu épithélial

Les tissus épithéliaux maintiennent leur intégrité par l'ajustement des tensions mécaniques et leur homéostasie par un équilibre entre les divisions cellulaires et extrusions. L'ensemble de ces mécanismes est lié aux tensions mécaniques générées au sein de ces tissus qui sont formés par des contacts forts entre cellules voisines par l'intermédiaire de jonctions adhérentes. Les travaux précédents de l'équipe montré que les mécanismes d'extrusion cellulaire au sein des tissus épithéliaux étaient liés à des défauts d'alignement des cellules et au stress mécanique engendré. De plus, cette analogie avec les cristaux liquides a mis en évidence un comportement mécanique différent entre les cellules individuelles et les monocouches épithéliales. En utilisant une approche multidisciplinaire combinant biologie cellulaire et biomécanique, ce travail de thèse a montré que la E-cadhérine joue un rôle clé dans la régulation de ces comportements mécaniques et dans la balance des forces entre adhésion à la matrice extra-cellulaire et aux cellules voisines : l'absence de E-cadhérine induit un renforcement des adhésions cellule-substrat et ainsi, des changements aux échelles multicellulaires. En comparant les cellules épithéliales avec ou sans cadhérine, nos résultats montrent des changements de contractilité à des échelles multicellulaires accompagnés de changements moléculaires au niveau des plaques d'adhésions focales et de l'activité du facteur de transcription YAP (Yes-associated protein). Les cellules compensent la perte d'adhérence cellule-cellule en renforçant leurs interactions au substrat. Les différences de comportements mécaniques entre les cellules WT et E-cadhérine KO induisent et expliquent les processus de ségrégation de ces groupes cellulaires en co-culture. De plus, nous observons l'extrusion de cellules vivantes (caspase négative) dans les tissus E-cadhérine alors que les cellules expulsées sont apoptotiques dans le cas normal. En développant des cultures 3D, nous montrons que l'extrusion se faisait au niveau basal dans les cellules E-cadhérine KO contrairement aux cellules normales. Les changements de contractilité de ces tissus épithéliaux et ces différents modes d'extrusion devraient permettre de mieux comprendre certains processus morphogénétiques ainsi que ceux liés la progression tumorale. Enfin, ce travail de thèse nous a permis d'étudier l'influence de la rigidité du substrat sur le maintien de l'intégrité épithéliale. Nous avons mis en évidence que les cellules épithéliales étaient sous tension/compression sur des substrats mous/rigides, le mode sous tension engendrant l'émergence de trous au sein des monocouches. Nous avons pu expliquer ce mécanisme par de fortes tensions locales générées par l'apparition de défauts topologiques -1/2.Epithelial tissues maintain homeostasis through a tight balance of cell division and cell apoptosis. Recent studies have shown cell division and apoptosis to be mechanotransductive processes. Mechanotransduction in epithelial tissues are driven by their ability to form strong contacts with their neighbours mediated through adherens junctions composed of cadherins and catenins. Using a combination of cell biology experiments, biophysical analysis tools and numerical simulations we show that E-cadherin plays a role in mediating force transduction between neighbouring cells while changing the force balance between cell-cell and cell-substrate interactions and hence, the contractility of cells within the tissue. In this work, we show that the switch between the single cell contractile behaviour and collective extensile behavior can be explained by the cellular ability to transmit tension through E-cadherin-based junctions. Changes in contractility in E-cadherin KO cells are accompanied by molecular changes such as increased levels of vinculin at focal adhesion (FA) sites and overall increase of FA areas as well as higher activity of YAP. This shows that these cells compensate for loss of cell-cell adhesion in the form of an increase in cell-substrate interaction. Differences in contractility of WT and E-cadherin cells were able to sort them into two different clusters in a co-culture. This sorting is accompanied by an increase in the rate of live cell extrusion (caspase negative) in the E-cadherin KO tissues in comparison to WT tissue where live extrusion was a rare event. In addition, we observed the direction of extrusion to be modified in E-cadherin KO in a 3D environment. This change in the direction of extrusion has been implicated in oncogenic extrusion. The contractility changes of E-cadherin KO tissues in combination with an altered mechanism of extrusion sheds light into the role of E-cadherin in maintaining epithelial tissue homeostasis, during cancer progression and epithelial-mesenchymal transition where E-cadherin is known to be downregulated using a framework of active mechanical tissue properties. Finally, we analyze the response of epithelial cells to substrate stiffness. We observe that epithelial integrity is challenged by the spontaneous formation of holes within monolayers when grown on soft substrates. Mechanical measurements including stress microscopy and laser ablation reveal that epithelial monolayers are tensile on soft and compressive on stiff substrates, favoring opening of holes on soft surfaces. Modeling the epithelium as an active nematic system shows that hole formation is triggered at trefoil-like topological rearrangements of cells resulting in high tensile stresses. This unanticipated response of cellular monolayers may provide a framework to understand bacterial infection, tumour progression and other morphogenetic processes

Preparation and optimization of various parameters of enteric coated pellets using the Taguchi L9 orthogonal array design and their characterization

Duloxetine hydrochloride enteric coated pellets were formulated using fluidized bed. Three separate layers, the drug layer, the barrier layer, and the enteric layer, were coated onto the inert core pellets. The pellets were optimized with the acid resistance and drug release in simulated intestinal fluid as the process parameters, using the Taguchi L9 orthogonal array. Various other properties, such as surface morphology, bulk and tapped density, Hausner's ratio, hardness, friability, yield of pellets, moisture content, and particle size distribution, were also studied in the optimized pellets. The concentration of the enteric polymer played a vital role in acid resistance, while the type of enteric polymer affected the drug release in simulated intestinal fluid. In both cases, it was determined that binder polymer concentration was not affected much. The comparisons between the optimized pellets and a market formulation yielded f1 and f2 values within a range of 4–5 and 60–65, respectively. Three month stability studies, conducted at accelerated conditions, showed the optimized pellets to be stable. Taguchi plays an important role in optimizing parameters, and optimization of duloxetine hydrochloride can be achieved with minimal trials

Active nematics across scales from cytoskeleton organization to tissue morphogenesis

International audienceBiological tissues are composed of various cell types working cooperatively to perform their respective function within organs and the whole body. During development, embryogenesis followed by histogenesis relies on orchestrated division, death, differentiation and collective movements of cellular constituents. These cells are anchored to each other and/or the underlying substrate through adhesion complexes and they regulate force generation by active cytoskeleton remodelling. The resulting contractility related changes at the level of each single cell impact tissue architecture by triggering changes in cell shape, cell movement and remodelling of the surrounding environment. These out of equilibrium processes occur through the consumption of energy, allowing biological systems to be described by active matter physics. ‘Active nematics’ a subclass of active matter encompasses cytoskeleton filaments, bacterial and eukaryotic cells allowing them to be modelled as rod-like elements to which nematic liquid crystal theories can be applied. In this review, we will discuss the concept of active nematics to understand biological processes across subcellular and multicellular scales, from single cell organization to cell extrusion, collective cell movements, differentiation and morphogenesis

Design of a novel bilayered gastric mucoadhesive system for localized and unidirectional release of lamotrigine

AbstractLamotrigine is a BCS class II drug with pH dependent solubility. The bilayered gastric mucoadhesive tablets of lamotrigine were designed such that the drug and controlled release polymers were incorporated in the upper layer and the lower layer had the mucoadhesive polymers. The major ingredients selected for the upper layer were the drug and control release polymer (either HPMC K15M or polyox) while the lower MA layer predominantly comprised of Carbopol 974P. A 23 full factorial design was constructed for this study and the tablets were optimized for parameters like tablet size, shape, ex vivo mucoadhesive properties and unidirectional drug release. Oval tablets with an average size of 14mm diameter were set optimum. Maximum mucoadhesive bond strength of 79.3±0.91*103dyn/cm2 was achieved with carbopol when used in combination with a synergistic resin polymer. All the tested formulations presented a mucoadhesion time of greater than 12h. The incorporation of methacrylic polymers in the lower layer ensured unidirectional drug release from the bilayered tablets. The unidirectional drug release was confirmed after comparing the dissolution results of paddle method with those of a modified basket method. Model independent similarity and dissimilarity factor methods were used for the comparison of dissolution results. Controlled drug release profiles with zero order kinetics were obtained with polyox and HPMC K15M which reported t90% at 6th and 12th hours, respectively. The “n” value with polyox was 0.992 and that with HPMC K15M was 0.946 indicating an approximate case II transport. These two formulations showed the potential for oral administration of lamotrigine as bilayered gastric mucoadhesive tablets by yielding highest similarity factor values, 96.06 and 92.47, respectively, between the paddle and modified basket method dissolution release profiles apart from reporting the best tablet physical properties and maximum mucoadhesive strength