Serotonin and Dopamine Protect from Hypothermia/Rewarming Damage through the CBS/ H2S Pathway

Biogenic amines have been demonstrated to protect cells from apoptotic cell death. Herein we show for the first time that serotonin and dopamine increase H2S production by the endogenous enzyme cystathionine-β-synthase (CBS) and protect cells against hypothermia/rewarming induced reactive oxygen species (ROS) formation and apoptosis. Treatment with both compounds doubled CBS expression through mammalian target of rapamycin (mTOR) and increased H2S production in cultured rat smooth muscle cells. In addition, serotonin and dopamine treatment significantly reduced ROS formation. The beneficial effect of both compounds was minimized by inhibition of their re-uptake and by pharmacological inhibition of CBS or its down-regulation by siRNA. Exogenous administration of H2S and activation of CBS by Prydoxal 5′-phosphate also protected cells from hypothermic damage. Finally, serotonin and dopamine pretreatment of rat lung, kidney, liver and heart prior to 24 h of hypothermia at 3°C followed by 30 min of rewarming at 37°C upregulated the expression of CBS, strongly reduced caspase activity and maintained the physiological pH compared to untreated tissues. Thus, dopamine and serotonin protect cells against hypothermia/rewarming induced damage by increasing H2S production mediated through CBS. Our data identify a novel molecular link between biogenic amines and the H2S pathway, which may profoundly affect our understanding of the biological effects of monoamine neurotransmitters

Interdependency of subsurface carbon distribution and graphene-catalyst interaction.

The dynamics of the graphene-catalyst interaction during chemical vapor deposition are investigated using in situ, time- and depth-resolved X-ray photoelectron spectroscopy, and complementary grand canonical Monte Carlo simulations coupled to a tight-binding model. We thereby reveal the interdependency of the distribution of carbon close to the catalyst surface and the strength of the graphene-catalyst interaction. The strong interaction of epitaxial graphene with Ni(111) causes a depletion of dissolved carbon close to the catalyst surface, which prevents additional layer formation leading to a self-limiting graphene growth behavior for low exposure pressures (10(-6)-10(-3) mbar). A further hydrocarbon pressure increase (to ∼10(-1) mbar) leads to weakening of the graphene-Ni(111) interaction accompanied by additional graphene layer formation, mediated by an increased concentration of near-surface dissolved carbon. We show that growth of more weakly adhered, rotated graphene on Ni(111) is linked to an initially higher level of near-surface carbon compared to the case of epitaxial graphene growth. The key implications of these results for graphene growth control and their relevance to carbon nanotube growth are highlighted in the context of existing literature.R.S.W. acknowledges a Research Fellowship from St. John’s College, Cambridge. S.H. acknowledges funding from ERC grant InsituNANO (No. 279342) and EPSRC under grant GRAPHTED (Ref. EP/K016636/1). We acknowledge the Helmholtz-Zentrum-Berlin Electron storage ring BESSY II for provision of synchrotron radiation at the ISISS beamline and we thank the BESSY staff for continuous support of our experiments. This research was partially supported by the EU FP7 Work Programme under grant Graphene Flagship (No. 604391). PRK acknowledges funding the Cambridge Commonwealth Trust. H.A. and C.B. acknowledge J.-Y. Raty and B. Legrand for fruitful discussions.This is the final published version. It's also available from ACS at http://pubs.acs.org/doi/abs/10.1021/ja505454v

In Situ Observations during Chemical Vapor Deposition of Hexagonal Boron Nitride on Polycrystalline Copper.

Using a combination of complementary in situ X-ray photoelectron spectroscopy and X-ray diffraction, we study the fundamental mechanisms underlying the chemical vapor deposition (CVD) of hexagonal boron nitride (h-BN) on polycrystalline Cu. The nucleation and growth of h-BN layers is found to occur isothermally, i.e., at constant elevated temperature, on the Cu surface during exposure to borazine. A Cu lattice expansion during borazine exposure and B precipitation from Cu upon cooling highlight that B is incorporated into the Cu bulk, i.e., that growth is not just surface-mediated. On this basis we suggest that B is taken up in the Cu catalyst while N is not (by relative amounts), indicating element-specific feeding mechanisms including the bulk of the catalyst. We further show that oxygen intercalation readily occurs under as-grown h-BN during ambient air exposure, as is common in further processing, and that this negatively affects the stability of h-BN on the catalyst. For extended air exposure Cu oxidation is observed, and upon re-heating in vacuum an oxygen-mediated disintegration of the h-BN film via volatile boron oxides occurs. Importantly, this disintegration is catalyst mediated, i.e., occurs at the catalyst/h-BN interface and depends on the level of oxygen fed to this interface. In turn, however, deliberate feeding of oxygen during h-BN deposition can positively affect control over film morphology. We discuss the implications of these observations in the context of corrosion protection and relate them to challenges in process integration and heterostructure CVD.P.R.K. acknowledges funding from the Cambridge Commonwealth Trust and the Lindemann Trust Fellowship. R.S.W. acknowledges a research fellowship from St. John’s College, Cambridge. S.H. acknowledges funding from ERC grant InsituNANO (no. 279342), EPSRC under grant GRAPHTED (project reference EP/K016636/1), Grant EP/H047565/1 and EU FP7 Work Programme under grant GRAFOL (project reference 285275). The European Synchrotron Radiation Facility (ESRF) is acknowledged for provision of synchrotron radiation and assistance in using beamline BM20/ROBL. We acknowledge Helmholtz-Zentrum-Berlin Electron storage ring BESSY II for synchrotron radiation at the ISISS beamline and continuous support of our experiments.This is the final version. It was first published by ACS at http://pubs.acs.org/doi/abs/10.1021/cm502603

Strategiczne wyzwania w sieciach interesariuszy

Shareholders of a company must increasingly share power with other social actors that control access to critical resources. These social actors are stakeholders because they have stakes in firms’ operations, either through being affected by them or through being able to affect them. Stakeholders are embedded in networks of relationships in which resources are shared, combined, exploited or restricted, and informal governance modes emerge. Strategic maneuvering in stakeholder networks is critical for assuring a firm’s access to valuable resources and resulting performance. Managers deciding on the strategic course of a firm embedded in a stakeholder network face multi-dimensional problems with multiple causes. It is argued that a three-way integration of the resource dependence theory, social network analysis, and stakeholder theory yields important insights for managers on options of strategic maneuvering in stakeholder networks. We highlight previous attempts to integrate pairs of these theories. Building on Boutilier’s typology of stakeholder network structures, we describe emerging governance patterns, and propose a set of possible moves aiming to address strategic challenges in gaining access to resources controlled by stakeholders.Akcjonariusze firm w coraz większym stopniu muszą dzielić się władzą z innymi aktorami społecznymi, którzy kontrolują dostęp do cennych zasobów. Ci aktorzy społeczni określani są jako interesariusze, ponieważ działania firm są powiązane z ich interesami dwojakiego rodzaju relacjami: interesariusze wpływają na działania firm i/lub działania firm wpływają na sytuację interesariuszy. Interesariusze są osadzeni w sieciach relacji, w których występują procesy dzielenia się, kombinacji, eksploatacji i ograniczania dostępu do zasobów w oparciu o nieformalny, wyłaniający się ład. Strategiczne manewry w sieciach interesariuszy mają krytyczne znaczenie dla zapewnienia dostępu do wartościowych zasobów i w efekcie do wyników osiąganych przez uczestników sieci. Menedżerowie podejmujący decyzje o kierunkach strategii działania firmy osadzonej w sieci interesariuszy mają do czynienia z wielowymiarowym problemem decyzyjnym. W artykule autorzy przedstawiają propozycję integracji trzech nurtów teoretycznych: teorii zależności zasobowej, analizy sieci społecznych i teorii interesariuszy, dzięki czemu możliwe wydaje się wsparcie procesu decyzyjnego, który pozwala skutecznie manewrować w sieciach interesariuszy. Podkreślają wcześniejsze próby integracji par omawianych teorii i nieliczne prace, w których podjęto integrację trzech strumieni literatury. Na podstawie typologii struktur sieciowych Boutiliera przedstawiają wyłanianie się ładu i wzorców działania w strukturze sieci, dzięki którym możliwe jest sprostanie strategicznym wyzwaniom uzyskania dostępu do zasobów w sieci

A Natural Language Processing Approach to Social License Management

Dealing with the social and political impacts of large complex projects requires monitoring and responding to concerns from an ever-evolving network of stakeholders. This paper describes the use of text analysis algorithms to identify stakeholders’ concerns across the project life cycle. The social license (SL) concept has been used to monitor the level of social acceptance of a project. That acceptance can be assessed from the texts produced by stakeholders on sources ranging from social media to personal interviews. The same texts also contain information on the substance of stakeholders’ concerns. Until recently, extracting that information necessitated manual coding by humans, which is a method that takes too long to be useful in time-sensitive projects. Using natural language processing algorithms, we designed a program that assesses the SL level and identifies stakeholders’ concerns in a few hours. To validate the program, we compared it to human coding of interview texts from a Bolivian mining project from 2009 to 2018. The program’s estimation of the annual average SL was significantly correlated with rating scale measures. The topics of concern identified by the program matched the most mentioned categories defined by human coders and identified the same temporal trends

Local Propagation in Conditional Gaussian Bayesian Networks

This paper describes a scheme for local computation in conditional Gaussian Bayesian networks that combines the approach of Lauritzen and Jensen (2001) with some elements of Shachter and Kenley (1989). Message passing takes place on an elimination tree structure rather than the more compact (and usual) junction tree of cliques. This yields a local computation scheme in which all calculations involving the continuous variables are performed by manipulating univariate regressions, and hence matrix operations are avoided