533 research outputs found
The effects of Wnt5a and Wnt3a and PCP signaling on Schwann cell biology and myelination
No full textPlanar cell polarity (PCP) is known as the polarization of cells within the plane of the tissue layer. This form of polarization controls several epithelial and non-epithelial morphological processes, such as the orientation of primary cilia in the inner ear, convergent extension (CE) and directed migration. A three tiered model of PCP regulation has been proposed which consists of the global, core, and effector modules. However there is one addition level of modulation through non-canonical Wnt signaling pathway. Of the many Wnt proteins a few have been identified to signal primarily through this pathway. One such protein is Wnt5a, which has been shown to modulate PCP during directed cell migration. In this study we gather preliminary data for the presence of PCP signaling components in Schwann cells and investigate the effect of Wnt5a and its antagonist Wnt3a on Schwann cell proliferation, migration and myelination.M.S.Includes bibliographical referencesby Neha Jan
The effects of immediate versus delayed feedback after multiple-choice questions on subsequent exam performance
No full textThis thesis investigates the effects of immediate versus delayed feedback following multiple-choice questions on subsequent performance on multiple-choice and recall questions. In three experiments, students in a college psychology lecture course received immediate or delayed feedback following multiple-choice questions on an initial unit exam which was followed up with exam(s) including both multiple-choice and short-answer questions. In the first experiment, the kind of feedback did not affect performance on the same multiple-choice questions when they were repeated on the final. In the second experiment, two subsequent follow-up exams included first a short-answer version of the multiple-choice question and then the same multiple-choice question. Performance on the short-answer questions was better following delayed feedback than following immediate feedback. However, the kind of feedback had no effect on the performance of the repeated multiple-choice questions. Also, the interval between the initial exam and the follow-up exam had no effect on performance. The third experiment examined whether delayed feedback increased confidence more than immediate feedback and whether the increase in confidence mediated the improved performance on subsequent short-answer questions. The delayed feedback had no effect on confidence for the subsequent short-answer and multiple-choice responses. Together, these results demonstrate that delayed feedback improves performance on the short-answer questions by increasing the subsequent generation of the correct response but does not influence recognition of it.M.S.Includes bibliographical referencesIncludes vitaby Neha Sinh
Moral Panic, Social Exclusion and The Human Rights of Same-Sex Partners in Ghana-RETRACTED
No full textThis article is retracted :
The retraction is based on the request of the author, Dr. Neha Jain, as it contains some exclusive and private data of a community out of India, that should not be released online. https://doi.org/10.55938/ijgasr.v1i3.20
Sincerely,Editorial Team, IJGASR
Announcement: https://journals.icapsr.com/index.php/ijgasr/announcement/view/17
Effect of Molecular Composition of Heparin and Cellulose Sulfate on Multilayer Formation and Cell Response
No full textHere, the layer-by-layer method was applied to assemble films from chitosan paired with either heparin or a semisynthetic cellulose sulfate (CS) that possessed a higher sulfation degree than heparin. Ion pairing was exploited during multilayer formation at pH 4, while hydrogen bonding is likely to occur at pH 9. Effects of polyanions and pH value during layer formation on multilayers properties were studied by surface plasmon resonance ("dry layer mass"), quartz crystal microbalance with dissipation monitoring ("wet layer mass"), water contact angle, and zeta potential measurements. Bioactivity of multilayers was studied regarding fibronectin adsorption and adhesion/proliferation of C2C12 myoblast cells. Layer growth and dry mass were higher for both polyanions at pH 4 when ion pairing occurred, while it decreased significantly with heparin at pH 9. By contrast, CS as polyanion resulted also in high layer growth and mass at pH 9, indicating a much stronger effect of hydrogen bonding between chitosan and CS. Water contact angle and zeta potential measurements indicated a more separated structure of multilayers from chitosan and heparin at pH 4, while CS led to a more fuzzy intermingled structure at both pH values. Cell behavior was highly dependent on pH during multilayer formation with heparin as polyanion and was closely related to fibronectin adsorption. By contrast, CS and chitosan did not show such dependency on pH value, where adhesion and growth of cells was high. Results of this study show that CS is an attractive candidate for multilayer formation that does not depend so strongly on pH during multilayer formation. In addition, such multilayer system also represents a good substrate for cell interactions despite the rather soft structure. As previous studies have shown specific interaction of CS with growth factors, multilayers from chitosan and CS may be of great interest for different biomedical applications
Study on multilayer structures prepared from heparin and semi-synthetic cellulose sulfates as polyanions and their influence on cellular response
No full textMultilayer coatings of polycationic chitosan paired with polyanionic semi-synthetic cellulose sulfates or heparin were prepared by the layer-by-layer method. Two different cellulose sulfates (CS) with high (CS2.6) and intermediate (CS1.6) sulfation degree were prepared by sulfation of cellulose. Multilayers were fabricated at pH 4 and the resulting films were characterized by several methods. The multilayer 'optical' mass, measured by surface plasmon resonance, showed little differences in the total mass adsorbed irrespective of which polyanion was used. In contrast, 'acoustic' mass, calculated from quartz crystal micro balance with dissipation monitoring, showed the lowest mass and dissipation values for CS2.6 (highest sulfation degree) multilayers indicating formation of stiffer layers compared to heparin and CS1.6 layers which led to higher mass and dissipation values. Water contact angle and zeta potential measurements indicated formation of more distinct layers with using heparin as polyanion, while use of CS1.6 and CS2.6 resulted into more fuzzy intermingled multilayers. CS1.6 multilayers significantly supported adhesion and growth of C2C12 cells where as only few cells attached and started to spread initially on CS2.6 layers but favoured long term cell growth. Contrastingly cells adhered and grew poorly on to the layers of heparin. This present study shows that cellulose sulfates are attractive candidates for multilayer formation as potential substratum for controlled cell adhesion. Since a peculiar interaction of cellulose sulfates with growth factors was found during previous studies, immobilization of cellulose sulfate in multilayer systems might be of great interest for tissue engineering applications
Modulating cell behaviour through biomimetic multilayers of natural and semi-synthetic glycosaminoglycans
No full textDie Dissertation soll den Einfluss der Zusammensetzung von Polyanionen und pH Wert Änderungen während der Bildung von Polyelektrolytmultischichten (PEM) auf das Zellverhalten untersuchen. PEM aus Heparin und halbsynthetischen Zellulosesulfaten (CS) mit unterschiedlichen Sulfatierungsgraden als Polyanionen und Chitosan als Polykation wurden mittels Layer-by-Layer-Methode bei verschiedenen pH Werten hergestellt. CS wurden verwendet, da diese bioaktive, mitogene und osteogene Eigenschaften besitzen. Zur Änderung der PEM Eigenschaften wurde der pH Wert der einzelnen Schichten variiert. PEM wurden durch unterschiedliche Methoden charakterisiert, welche zeigten, dass Schichtaufbau und Eigenschaften vom pH Wert und der Art der Polyanion abhängig sind. Zellstudien belegten die Fähigkeit der PEM, die Adhäsion und das Wachstum von C2C12 Zellen steuern zu können. Es konnte bestätigt werden, dass analog zu Heparin auch CS attraktive Alternativen für die Ausbildung von bioaktiven PEM darstellen, welche von großem Interesse für verschiedene biomedizinische Anwendungen sind.This thesis is aimed to investigate the effect of molecular composition of polyanions and pH variation during polyelectrolyte multilayers (PEM) formation to control cellular behaviour on multilayer coated substrates. PEM of heparin and semi-synthetic cellulose sulfates (CS) with varying sulfation degree as polyanions and chitosan as polycation were prepared using layer-by-layer method at different pH values. CS were applied as they are highly bioactive with mitogenic and osteogenic activity. pH variation was used to control the properties of layers. PEM were characterized by several physico-chemical methods which showed that multilayer growth and surface features were dependent on pH value and type of polyanion. Cell studies proved the ability of these layers to modulate adhesion and growth of C2C12 cells. It was shown that along with heparin, CS are also attractive candidates for PEM formation with high bioactivity that could be of great interest for different biomedical applications.von Neha Aggarwa
Correction to: A cell-cycle signature classifier for pan-cancer analysis
No full textIn the original published version, the list of authors was incomplete. Theodora A. Constantin was missing, and Neha Tabassum and Theodora A. Constantin share first authorship. The correct author list is given above. The original article has been corrected. DOI to original article: https://doi.org/10.1038/s41388-020-01426-
Less-institutionalized social structures: a theoretical, methodological, and empirical analysis of how networks and culture matter for emergence
No full textUsing a networks and culture lens, I investigate the micro-level processes underlying the production of order in social contexts or locations that are relationally-defined and meaningful, but lack cultural cues to action and interpretation or are in the early stages of acquiring such meaning. Drawing on neoinstitutionalist theory, I refer to such social structures as less-institutionalized. To explain order in the absence of situational cultural cues literature in social network analysis has traditionally attributed regularities to situational structural tendencies that preclude shared understandings and/or subjective engagement. Recent literature in the sociology of culture that revives overarching moral intuitions as a basis for action similarly rejects the explanatory value of situational cultural cues. Arguing that culture is neither irrelevant nor implicated in an overarching way in culturally less-institutionalized situations, I posit that order can be linked to individuals’ tacit and discursive use of cultural repertoires acquired over the life-course through involvements in multiple networks of interaction and domains of shared meanings or ‘netdoms.’ I analytically distinguish between three categories of less-institutionalized situations of the basis of the degree of uncertainty in interpretation and action they impose upon their occupants: high, intermediate, and absence/low. I demonstrate my argument using three examples of less-institutionalized situations/positions from distinct sociological fields: (1) rapid labor-force feminization in South Asia (high-uncertainty); (2) an emergent area of knowledge production (intermediate-uncertainty); and (3) falling average sibship-size implicated in worldwide fertility decline (low/absent uncertainty). Elaborating upon three cross-netdom mechanisms - analogizing, contrasting, and spillovers – and using a mixture of interpretive techniques, multilevel statistical models, and exponential random graph models, I show that occupants use cultural repertoires discursively in high-uncertainty less-institutionalized positions, tacitly in low-uncertainty situations, and in a combination of tacit and deliberative ways under conditions of intermediate uncertainty. I also develop a mathematical model to show how less-institutionalized practices/interpretations can come to be institutionalized over time through management of uncertainty within homophilous networks. Lastly, positing a duality between the cultural repertoires of individuals and those of social locations, I conclude with a discussion on how less-institutionalized positions offer a unique window into investigating processes of emergence and social change.Ph. D.Includes bibliographical referencesIncludes vitaby Neha Gonda
Competing bimetallic ratios: Amsterdam, London and bullion arbitrage in the 18th century
No full textThis article analyses the stability of bimetallism in the mid-18th century for the case of two large centres that had different legal ratios and only one international market ratio. A new theoretical framework is articulated for the situation of international independence to set legal bimetallic ratios by monetary authorities in different countries. Then, using new data handcollected from archival sources and relevant to the two main bullion markets in the 18th century, Amsterdam and London, this theoretical framework is utilised to identify the regimes that actually prevailed during that period, in which Amsterdam was effectively on the bimetallic standard while London was on the gold standard de facto.Bimetallism, Bimetallic stability, Bullion markets, Arbitrage, Specie-point mechanism, Melting-minting points
Regional empty marine container management
No full textEmpty container repositioning is one of the longstanding and ongoing issues in the containerized maritime trade. Even though it is a non-revenue generating, expensive and undesirable exercise, it is an integral part of an overall efficient global transportation system, which balances demand and supply of empty containers between regions. Empty containers are repositioned at three levels - global, inter-regional and regional-level. The focus of this dissertation is at the regional level of empty container repositioning.
Regional repositioning of empty containers involves empty container movement between regional importers, marine terminals, empty container depots, and export customers. This chain movement generates excessive unproductive empty vehicle miles in a region. The problem of empty vehicle miles travelled becomes more prominent when empty container depots are located close to the port and import and export customers are inland. Stakeholders incur large system costs in repositioning empty containers between the regional import-export business locations and the port/depots. Regions with high import activity are concerned with the increase in containerized trade volumes and the persistent trade imbalance because of the capacity shortfall at their existing depots.
This thesis addresses the above two regional concerns of excessive empty vehicle miles and empty container storage capacity shortfall by proposing an 'Inland-Depots-for-Empty-Containers (IDEC)' system. It recommends opening new empty container depots inland in the region, closer to high volume import-export customer clusters, in addition to the depots currently being located near the ports. The dissertation discusses the feasibility, viability, and effectiveness of the proposed system.
It develops mathematical models for the IDEC system to determine the optimal number and location of inland depots in a given region under deterministic and stochastic demand patterns. Exploiting the structure of the NP-hard problem, it develops a heuristic based on the randomized rounding algorithm to solve large scale, realistic depot-location problems. To implement a successful and sustainable IDEC system, it explicitly considers the varied perspectives of different maritime stakeholders involved in the container movement. Based on the models and quantitative analyses, it demonstrates that an IDEC system has great potential in improving regional empty moves, increasing both business profitability and social welfare simultaneously.Ph.D.Includes bibliographical references (p. 133-144)
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