126 research outputs found
Multi-Scale Modelling of Aggregation of TiO2 Nanoparticle Suspensions in Water
Titanium dioxide nanoparticles have risen concerns about their possible toxicity and the European Food Safety Authority recently banned the use of TiO2 nano-additive in food products. Following the intent of relating nanomaterials atomic structure with their toxicity without having to conduct large-scale experiments on living organisms, we investigate the aggregation of titanium dioxide nanoparticles using a multi-scale technique: starting from ab initio Density Functional Theory to get an accurate determination of the energetics and electronic structure, we switch to classical Molecular Dynamics simulations to calculate the Potential of Mean Force for the connection of two identical nanoparticles in water; the fitting of the latter by a set of mathematical equations is the key for the upscale. Lastly, we perform Brownian Dynamics simulations where each nanoparticle is a spherical bead. This coarsening strategy allows studying the aggregation of a few thousand nanoparticles. Applying this novel procedure, we find three new molecular descriptors, namely, the aggregation free energy and two numerical parameters used to correct the observed deviation from the aggregation kinetics described by the Smoluchowski theory. Ultimately, molecular descriptors can be fed into QSAR models to predict the toxicity of a material knowing its physicochemical properties, enabling safe design strategies
Recommended from our members
Corporate governance and national institutions: A review and emerging research agenda
We present a critique of corporate governance research grounded in agency theory and propose that cross-national comparison of corporate governance should consider how the nature and extent of agency relationships differ across different institutional contexts. Building on prior governance studies grounded in sociology and organizational theory we argue that performance outcomes of boards of directors, ownership concentration, and executive incentives may differ depending on the legal system and institutional characteristics in a specific country. Institutions may also affect the extent of complimentarity/substitution among different firm-level governance practices producing patterned variations in firm-level governance mechanisms. Our discussion suggests that researchers need to develop more holistic, institutionally embedded governance framework to analyze organizational outcomes of various governance practices
Inflammation and tissue repair markers distinguish the nodular sclerosis and mixed cellularity subtypes of classical Hodgkin's lymphoma
Background:
Classical Hodgkin's lymphoma (cHL), although a malignant disease, has many features in common with an inflammatory condition. The aim of this study was to establish the molecular characteristics of the two most common cHL subtypes, nodular sclerosis (NS) and mixed cellularity (MC), based on molecular profiling and immunohistochemistry, with special reference to the inflammatory microenvironment.
Methods:
We analysed 44 gene expression profiles of cHL whole tumour tissues, 25 cases of NS and 19 cases of MC, using Affymetrix chip technology and immunohistochemistry.
Results:
In the NS subtype, 152 genes showed a significantly higher expression, including genes involved in extracellular matrix (ECM) remodelling and ECM deposition similar to wound healing. Among these were SPARC, CTSK and COLI. Immunohistochemistry revealed that the NS-related genes were mainly expressed by macrophages and fibroblasts. Fifty-three genes had a higher expression in the MC subtype, including several inflammation-related genes, such as C1Qα, C1QÎČ and CXCL9. In MC tissues, the C1Q subunits were mainly expressed by infiltrating macrophages.
Conclusions and interpretations:
We suggest that the identified subtype-specific genes could reflect different phases of wound healing. Our study underlines the potential function of infiltrating macrophages in shaping the cHL tumour microenvironment
Recommended from our members
CORPORATE GOVERNANCE AND INVESTORS' PERCEPTIONS OF FOREIGN IPO VALUE: AN INSTITUTIONAL PERSPECTIVE
We build on sociology-grounded research on financial market behavior and suggest a ânestedâ legitimacy framework to explore U.S. investor perceptions of foreign IPO value. We draw on a fuzzy-set theoretic approach to demonstrate how different combinations of monitoring and incentive-based corporate governance mechanisms lead to the same level of investor valuations of firms. We also argue that institutional factors related to the minority shareholder protection strength in the foreign IPOâs home country represent a boundary condition that affects the number of governance mechanisms required to achieve U.S. investorsâ high value perceptions. Our findings, drawn from a unique, hand-collected dataset of foreign IPOs in the U.S, contribute to the sociological perspective on comparative corporate governance and the inter-dependencies between organizations and institutions
CSR, co-optation and resistance: the emergence of new agnostic relations between business and civil society
This article examines the theoretical implications of the changing relationships between NGOs and businesses that have emerged as a response to the evolving agenda around CSR and sustainable development. In particular, it focuses upon examining whether greater engagement from non-governmental organisations (NGOs) in this area reflects a process of appropriation and co-optation of protest by the business community. To examine this process, the article considers two forms of appropriationâappropriation of language and appropriation via participationâas a basis for discussion. While co-optation pressures are identified within both areas, the article argues that co-optation is identified almost as an inevitable outcome of engagement without significant consideration of the ability of movements to identify and respond to these processes. In identifying an alternative approach, the article utilises Mouffeâs framework of agonistic pluralism. Mouffeâs framework, it is argued, provides an understanding of the way in which agonistic relationships are emerging between NGOs and businesses while highlighting the continuance of conflict between parties struggling to influence the contested interpretations of responsible business
Foreign ownership, bank information environments, and the international mobility of corporate governance
This paper investigates how foreign ownership shapes bank information environments. Using a sample of listed banks from 60 countries over 1997â2012, we show that foreign ownership is significantly associated with greater (lower) informativeness (synchronicity) in bank stock prices. We also find that stock returns of foreign-owned banks reflect more information about future earnings. In addition, the positive association between price informativeness and foreign ownership is stronger for foreign-owned banks in countries with stronger governance, stronger banking supervision, and lower monitoring costs. Overall, our evidence suggests that foreign ownership reduces bank opacity by exporting governance, yielding important implications for regulators and governments
EXECUTIVE PAY AND PERFORMANCE IN PORTUGUESE LISTED COMPANIES
This essay analyses the relationship between corporate governance practices and Chief Executive Officer (CEO) wages from a sample of Portuguese listed companies over the period from 2002-2011. The relationship between CEO total compensation and shareholders return, firm characteristics, CEO characteristics, board of directors and shareholders characteristics is analysed. It is found that firm specific factors accounts for the majority of the variance in total CEO pay, while firm performance accounts for less than 5%. It is also found that the CEO characteristics, board of directorsâ structures, and shareholders features are related with the CEO pay. The policy implications of these results are then derived
- âŠ