Peroxisome proliferator-activated receptor activators modulate the osteoblastic maturation of MC3T3-E1 preosteoblasts

AbstractThe reduced bone mineral density (BMD) observed in osteoporosis results, in part, from reduced activity of bone-forming osteoblasts. We examined the effect of peroxisome proliferator-activated receptor (PPAR) activators on MC3T3-E1 preosteoblast maturation. Activators of PPARα, δ and γ induced alkaline phosphatase activity, matrix calcification and the expression of osteoblast genes as determined by reverse transcriptase-polymerase chain reaction. However, at relatively high concentrations of the specific PPARγ ligands, ciglitazone and troglitazone, maturation was inhibited. PPARα, δ and γ1 were expressed in MC3T3-E1 cells. PPARγ1 mRNA and protein levels were induced early during osteoblastic maturation. We speculate that endogenous and pharmacological PPAR activators may affect BMD by modulating osteoblastic maturation

Strong atmospheric chemistry feedback to climate warming from Arctic methane emissions

Author Posting. © American Geophysical Union, 2011. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Global Biogeochemical Cycles 25 (2011): GB2002, doi:10.1029/2010GB003845.The magnitude and feedbacks of future methane release from the Arctic region are unknown. Despite limited documentation of potential future releases associated with thawing permafrost and degassing methane hydrates, the large potential for future methane releases calls for improved understanding of the interaction of a changing climate with processes in the Arctic and chemical feedbacks in the atmosphere. Here we apply a “state of the art” atmospheric chemistry transport model to show that large emissions of CH 4 would likely have an unexpectedly large impact on the chemical composition of the atmosphere and on radiative forcing (RF). The indirect contribution to RF of additional methane emission is particularly important. It is shown that if global methane emissions were to increase by factors of 2.5 and 5.2 above current emissions, the indirect contributions to RF would be about 250% and 400%, respectively, of the RF that can be attributed to directly emitted methane alone. Assuming several hypothetical scenarios of CH 4 release associated with permafrost thaw, shallow marine hydrate degassing, and submarine landslides, we find a strong positive feedback on RF through atmospheric chemistry. In particular, the impact of CH 4 is enhanced through increase of its lifetime, and of atmospheric abundances of ozone, stratospheric water vapor, and CO 2 as a result of atmospheric chemical processes. Despite uncertainties in emission scenarios, our results provide a better understanding of the feedbacks in the atmospheric chemistry that would amplify climate warming

ENGAGE Summary for Policymakers

As the world faces the risks of dangerous climate change, policymakers, industry and civil society leaders are counting on Integrated Assessment Models (IAMs) to inform and guide strategies to deliver on the objectives of the Paris Agreement (PA) and subsequent agreements. The Exploring National and Global Actions to Reduce Greenhouse Gas Emissions (ENGAGE) project has responded to this challenge by engaging these stakeholders in co-producing a new generation of global and national decarbonization pathways

Oxidative footprinting in the study of structure and function of membrane proteins: Current state and perspectives

Membrane proteins, such as receptors, transporters and ion channels, control the vast majority of cellular signalling and metabolite exchange processes and thus are becoming key pharmacological targets. Obtaining structural information by usage of traditional structural biology techniques is limited by the requirements for the protein samples to be highly pure and stable when handled in high concentrations and in nonnative buffer systems, which is often difficult to achieve for membrane targets. Hence, there is a growing requirement for the use of hybrid, integrative approaches to study the dyna mic and functional aspects of membrane proteins in physiologically relevant conditions. In recent years, significant progress has been made in the field of oxidative labelling techniques and in particular the X-ray radiolytic footprinting in combination with mass spectrometry (MS) (XF-MS), which provide residue-specific information on the solvent accessibility of proteins. In combination with both low- and high-resolution data from other structural biology approaches, it is capable of providing valuable insights into dynamics of membrane proteins, which have been difficult to obtain by other structural techniques, proving a highly complementary technique to address structure and function of membrane targets. XF-MS has demonstrated a unique capability for identification of structural waters and conformational changes in proteins at both a high degree of spatial and a high degree of temporal resolution. Here, we provide a perspective on the place of XF-MS among other structural biology methods and showcase some of the latest developments in its usage for studying water-mediated transmembrane (TM) signalling, ion transport and ligand-induced allosteric conformational changes in membrane proteins

Spintronics: Fundamentals and applications

Spintronics, or spin electronics, involves the study of active control and manipulation of spin degrees of freedom in solid-state systems. This article reviews the current status of this subject, including both recent advances and well-established results. The primary focus is on the basic physical principles underlying the generation of carrier spin polarization, spin dynamics, and spin-polarized transport in semiconductors and metals. Spin transport differs from charge transport in that spin is a nonconserved quantity in solids due to spin-orbit and hyperfine coupling. The authors discuss in detail spin decoherence mechanisms in metals and semiconductors. Various theories of spin injection and spin-polarized transport are applied to hybrid structures relevant to spin-based devices and fundamental studies of materials properties. Experimental work is reviewed with the emphasis on projected applications, in which external electric and magnetic fields and illumination by light will be used to control spin and charge dynamics to create new functionalities not feasible or ineffective with conventional electronics.Comment: invited review, 36 figures, 900+ references; minor stylistic changes from the published versio

The application of Graphene as a sample support in Transmission Electron Microscopy

Transmission electron microscopy has witnessed rampant development and surging point resolution over the past few years. The improved imaging performance of modern electron microscopes shifts the bottleneck for image contrast and resolution to sample preparation. Hence, it is increasingly being realized that the full potential of electron microscopy will only be realized with the optimization of current sample preparation techniques. Perhaps the most recognized issues are background signal and noise contributed by sample supports, sample charging and instability. Graphene provides supports of single atom thickness, extreme physical stability, periodic structure, and ballistic electrical conductivity. As an increasing number of applications adapting graphene to their benefit emerge, we discuss the unique capabilities afforded by the use of graphene as a sample support for electron microscopy.Comment: Review, to appear in solid state communication

Overview of the Role of Environmental Factors in Neurodevelopmental Disorders

Evidence implicates environmental factors in the pathogenesis of diverse complex neurodevelopmental disorders. However, the identity of specific environmental chemicals that confer risk for these disorders, and the mechanisms by which environmental chemicals interact with genetic susceptibilities to influence adverse neurodevelopmental outcomes remain significant gaps in our understanding of the etiology of most neurodevelopmental disorders. It is likely that many environmental chemicals contribute to the etiology of neurodevelopmental disorders but their influence depends on the genetic substrate of the individual. Research into the pathophysiology and genetics of neurodevelopmental disorders may inform the identification of environmental susceptibility factors that promote adverse outcomes in brain development. Conversely, understanding how low-level chemical exposures influence molecular, cellular, and behavioral outcomes relevant to neurodevelopmental disorders will provide insight regarding gene-environment interactions and possibly yield novel intervention strategies

Promoting novelty, rigor, and style in energy social science: towards codes of practice for appropriate methods and research design

A series of weaknesses in creativity, research design, and quality of writing continue to handicap energy social science. Many studies ask uninteresting research questions, make only marginal contributions, and lack innovative methods or application to theory. Many studies also have no explicit research design, lack rigor, or suffer from mangled structure and poor quality of writing. To help remedy these shortcomings, this Review offers suggestions for how to construct research questions; thoughtfully engage with concepts; state objectives; and appropriately select research methods. Then, the Review offers suggestions for enhancing theoretical, methodological, and empirical novelty. In terms of rigor, codes of practice are presented across seven method categories: experiments, literature reviews, data collection, data analysis, quantitative energy modeling, qualitative analysis, and case studies. We also recommend that researchers beware of hierarchies of evidence utilized in some disciplines, and that researchers place more emphasis on balance and appropriateness in research design. In terms of style, we offer tips regarding macro and microstructure and analysis, as well as coherent writing. Our hope is that this Review will inspire more interesting, robust, multi-method, comparative, interdisciplinary and impactful research that will accelerate the contribution that energy social science can make to both theory and practice

Perspectives and Integration in SOLAS Science

Why a chapter on Perspectives and Integration in SOLAS Science in this book? SOLAS science by its nature deals with interactions that occur: across a wide spectrum of time and space scales, involve gases and particles, between the ocean and the atmosphere, across many disciplines including chemistry, biology, optics, physics, mathematics, computing, socio-economics and consequently interactions between many different scientists and across scientific generations. This chapter provides a guide through the remarkable diversity of cross-cutting approaches and tools in the gigantic puzzle of the SOLAS realm. Here we overview the existing prime components of atmospheric and oceanic observing systems, with the acquisition of ocean–atmosphere observables either from in situ or from satellites, the rich hierarchy of models to test our knowledge of Earth System functioning, and the tremendous efforts accomplished over the last decade within the COST Action 735 and SOLAS Integration project frameworks to understand, as best we can, the current physical and biogeochemical state of the atmosphere and ocean commons. A few SOLAS integrative studies illustrate the full meaning of interactions, paving the way for even tighter connections between thematic fields. Ultimately, SOLAS research will also develop with an enhanced consideration of societal demand while preserving fundamental research coherency. The exchange of energy, gases and particles across the air-sea interface is controlled by a variety of biological, chemical and physical processes that operate across broad spatial and temporal scales. These processes influence the composition, biogeochemical and chemical properties of both the oceanic and atmospheric boundary layers and ultimately shape the Earth system response to climate and environmental change, as detailed in the previous four chapters. In this cross-cutting chapter we present some of the SOLAS achievements over the last decade in terms of integration, upscaling observational information from process-oriented studies and expeditionary research with key tools such as remote sensing and modelling. Here we do not pretend to encompass the entire legacy of SOLAS efforts but rather offer a selective view of some of the major integrative SOLAS studies that combined available pieces of the immense jigsaw puzzle. These include, for instance, COST efforts to build up global climatologies of SOLAS relevant parameters such as dimethyl sulphide, interconnection between volcanic ash and ecosystem response in the eastern subarctic North Pacific, optimal strategy to derive basin-scale CO2 uptake with good precision, or significant reduction of the uncertainties in sea-salt aerosol source functions. Predicting the future trajectory of Earth’s climate and habitability is the main task ahead. Some possible routes for the SOLAS scientific community to reach this overarching goal conclude the chapter