Organic materials have recently become of great interest for photovoltaic applications, due to their potential to utilise high throughput, solution phase processing, which will lead to low cost ...electricity production. Hybrid solar cells combine organic and inorganic materials with the aim of utilising the low cost cell production of organic photovoltaics (OPV) as well as obtaining other advantages, such as tuneable absorption spectra, from the inorganic component. Whilst hybrid solar cells have the potential to achieve high power conversion efficiencies (PCE), currently obtained efficiencies are quite low. The design of the inorganic material used as the electron acceptor in hybrid solar cells, particularly the electronic structure, is crucial to the performance of the device. There exists an optimal electronic structure design for an inorganic acceptor. To date, four major material types have been investigated, being cadmium compounds, silicon, metal oxide nanoparticles and low band gap nanoparticles. Currently, Cadmium Sulfide (CdS) quantum dots represent the state of the art, yielding a PCE of greater than 4%. This review compares the electronic structure of these materials with the optimal design components of an inorganic material and also explores possible limitations to the PCE of these devices, such as nanomorphology control and nanoparticle surface chemistry. This report provides the reader with a concise synthesis of the current state of the art for bulk heterojunction organic—inorganic hybrid solar cells. Additionally, it highlights key research areas which require attention to allow for the commercialisation of this technology.
► Hybrid solar cells combine both organic and inorganic materials. ► Different possible inorganic acceptor materials compared. ► Electronic structure of heterojunction heavily influences device performance. ► Major limitation of inorganic nanoparticles related to surface chemistry. ► New characterisation techniques help understand fundamental processes.
The effect of policy regimes on immigrant incorporation has been the subject of extensive debate. Despite much theoretical literature on the subject, the relationships between specific national ...policies in various domains and outcomes broadly related to social solidarity have not been well explored empirically. The present work develops measures tapping the priority of “ascriptive” traits defining membership in the national community. It tests the expectations of the theoretical literature on multiculturalism, citizenship policy, and social welfare redistribution against these measures across 18 immigrant-receiving democracies. Cross-sectional analyses on, 2003 data indicate that both jus soli citizenship regimes and high levels of social spending are related to more immigrant-inclusive definitions of the national community, but the effect of multiculturalism is inconsistent. Examined longitudinally, the effect of a jus soli citizenship regime and social spending remains consistent, but citizens in multicultural countries appear to have become substantially more “ascriptive” on these outcomes over time.
Liver fibrosis Wallace, Karen; Burt, Alastair D; Wright, Matthew C
Biochemical journal,
04/2008, Letnik:
411, Številka:
1
Journal Article
Recenzirano
Liver damage leads to an inflammatory response and to the activation and proliferation of mesenchymal cell populations within the liver which remodel the extracellular matrix as part of an ...orchestrated wound-healing response. Chronic damage results in a progressive accumulation of scarring proteins (fibrosis) that, with increasing severity, alters tissue structure and function, leading to cirrhosis and liver failure. Efforts to modulate the fibrogenesis process have focused on understanding the biology of the heterogeneous liver fibroblast populations. The fibroblasts are derived from sources within and out with the liver. Fibroblasts expressing alpha-smooth muscle actin (myofibroblasts) may be derived from the transdifferentiation of quiescent hepatic stellate cells. Other fibroblasts emerge from the portal tracts within the liver. At least a proportion of these cells in diseased liver originate from the bone marrow. In addition, fibrogenic fibroblasts may also be generated through liver epithelial (hepatocyte and biliary epithelial cell)-mesenchymal transition. Whatever their origin, it is clear that fibrogenic fibroblast activity is sensitive to (and may be active in) the cytokine and chemokine profiles of liver-resident leucocytes such as macrophages. They may also be a component driving the regeneration of tissue. Understanding the complex intercellular interactions regulating liver fibrogenesis is of increasing importance in view of predicted increases in chronic liver disease and the current paucity of effective therapies.
Retrieving high-content gene-expression information while retaining three-dimensional (3D) positional anatomy at cellular resolution has been difficult, limiting integrative understanding of ...structure and function in complex biological tissues. We developed and applied a technology for 3D intact-tissue RNA sequencing, termed STARmap (spatially-resolved transcript amplicon readout mapping), which integrates hydrogel-tissue chemistry, targeted signal amplification, and in situ sequencing. The capabilities of STARmap were tested by mapping 160 to 1020 genes simultaneously in sections of mouse brain at single-cell resolution with high efficiency, accuracy, and reproducibility. Moving to thick tissue blocks, we observed a molecularly defined gradient distribution of excitatory-neuron subtypes across cubic millimeter-scale volumes (>30,000 cells) and a short-range 3D self-clustering in many inhibitory-neuron subtypes that could be identified and described with 3D STARmap.
We have determined the three-dimensional (3D) architecture of the
Caulobacter crescentus genome by combining genome-wide chromatin interaction detection, live-cell imaging, and computational ...modeling. Using chromosome conformation capture carbon copy (5C), we derive ∼13 kb resolution 3D models of the
Caulobacter genome. The resulting models illustrate that the genome is ellipsoidal with periodically arranged arms. The
parS sites, a pair of short contiguous sequence elements known to be involved in chromosome segregation, are positioned at one pole, where they anchor the chromosome to the cell and contribute to the formation of a compact chromatin conformation. Repositioning these elements resulted in rotations of the chromosome that changed the subcellular positions of most genes. Such rotations did not lead to large-scale changes in gene expression, indicating that genome folding does not strongly affect gene regulation. Collectively, our data suggest that genome folding is globally dictated by the
parS sites and chromosome segregation.
► Chromatin interaction mapping and modeling elucidate
Caulobacter genome structure ► The genome is ellipsoidal with periodically arranged arms ► The
parS region shapes whole genome structure and affects chromatin compaction ► The
parS region is the only genomic region stably attached to the cell envelope
Later life marital patterns have undergone shifts over the past few decades, including a rapid growth of cohabiting unions. Despite the increase in older adult cohabitation, research on this ...population has been slow to keep up. Intimate relationships are linked to well-being and relationship quality is especially important because high-quality relationships offer a number of benefits for well-being, whereas poor-quality relationships often are detrimental. This study compares cohabiting and remarried individuals on two measures of relationship quality.
Using data from the 2010 and 2012 Health and Retirement Study, I investigate the positive and negative relationship quality of cohabitors relative to their remarried counterparts and whether the association of union type and relationship quality varies by race.
Across both positive and negative relationship quality, I found few differences between cohabiting and remarried individuals. Black cohabitors report higher positive relationship quality than remarrieds, whereas White cohabitors and remarrieds do not differ.
These findings suggest that cohabiting unions and remarriages are comparable among White older adults, but that Black cohabitors may gain more in terms of positive relationship quality than their remarried counterparts.
The clinical impact of the fibrate and thiazolidinedione drugs on dyslipidemia and diabetes is driven mainly through activation of two transcription factors, peroxisome proliferator-activated ...receptors (PPAR)-α and PPAR-γ. However, substantial differences exist in the therapeutic and side-effect profiles of specific drugs. This has been attributed primarily to the complexity of drug-target complexes that involve many coregulatory proteins in the context of specific target gene promoters. Recent data have revealed that some PPAR ligands interact with other non-PPAR targets. Here we review concepts used to develop new agents that preferentially modulate transcriptional complex assembly, target more than one PPAR receptor simultaneously, or act as partial agonists. We highlight newly described on-target mechanisms of PPAR regulation including phosphorylation and nongenomic regulation. We briefly describe the recently discovered non-PPAR protein targets of thiazolidinediones, mitoNEET, and mTOT. Finally, we summarize the contributions of on- and off-target actions to select therapeutic and side effects of PPAR ligands including insulin sensitivity, cardiovascular actions, inflammation, and carcinogenicity.
In recently developed approaches for high-resolution imaging within intact tissue, molecular characterization over large volumes has been largely restricted to labeling of proteins. But volumetric ...nucleic acid labeling may represent a far greater scientific and clinical opportunity, enabling detection of not only diverse coding RNA variants but also non-coding RNAs. Moreover, scaling immunohistochemical detection to large tissue volumes has limitations due to high cost, limited renewability/availability, and restricted multiplexing capability of antibody labels. With the goal of versatile, high-content, and scalable molecular phenotyping of intact tissues, we developed a method using carbodiimide-based chemistry to stably retain RNAs in clarified tissue, coupled with amplification tools for multiplexed detection. The resulting technology enables robust measurement of activity-dependent transcriptional signatures, cell-identity markers, and diverse non-coding RNAs in rodent and human tissue volumes. The growing set of validated probes is deposited in an online resource for nucleating related developments from across the scientific community.
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•Carbodiimide-based chemistry in CLARITY hydrogels for RNA preservation and detection•Rapid diffusion of DNA oligonucleotides for volumetric in situ hybridization•Detection of microRNAs and mRNAs in clarified mouse and human tissues•DNA-based amplification for multiplexed in situ hybridization in CLARITY
CLARITY with enhanced RNA coupling chemistry is developed for multiplexed, volumetric visualization of both long and short RNAs in a variety of intact tissues.
We consider an original variational approach for building new models of quintessence interacting with dark or baryonic matter. The coupling is introduced at the Lagrangian level using a variational ...formulation for relativistic fluids, where the interacting term generally depends on both the dynamical degrees of freedom of the theory and their spacetime derivatives. After deriving the field equations from the action, we consider applications in the context of cosmology. Two simple models are studied using dynamical system techniques showing the interesting phenomenology arising in this framework. We find that these models contain dark energy dominated late-time attractors with early-time matter dominated epochs and also obtain a possible dynamical crossing of the phantom barrier. The formulation and results presented here complete and expand the analysis exposed in the first part of this work, where only algebraic couplings, without spacetime derivatives, were considered.
The hippocampus is traditionally thought to transmit contextual information to limbic structures where it acquires valence. Using freely moving calcium imaging and optogenetics, we show that while ...the dorsal CA1 subregion of the hippocampus is enriched in place cells, ventral CA1 (vCA1) is enriched in anxiety cells that are activated by anxiogenic environments and required for avoidance behavior. Imaging cells defined by their projection target revealed that anxiety cells were enriched in the vCA1 population projecting to the lateral hypothalamic area (LHA) but not to the basal amygdala (BA). Consistent with this selectivity, optogenetic activation of vCA1 terminals in LHA but not BA increased anxiety and avoidance, while activation of terminals in BA but not LHA impaired contextual fear memory. Thus, the hippocampus encodes not only neutral but also valence-related contextual information, and the vCA1-LHA pathway is a direct route by which the hippocampus can rapidly influence innate anxiety behavior.
•Anxiogenic stimuli are differentially represented along the DV axis of the HPC•Inhibition of the vHPC in anxiogenic environments reduces avoidance behavior•vCA1 outputs to LHA but not BA control anxiety-related behavior•The majority of vCA1-LHA projection neurons represent anxiogenic stimuli
Jimenez et al. show that vCA1 neurons exhibit stable representations of anxiogenic environments that are required for avoidance behavior. The direct projection from vCA1 to the lateral hypothalamus is enriched in anxiety cells and can rapidly control anxiety-related behavior.
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