In the last two decades, dye-sensitized solar cells (DSSCs) have attracted more attention as an efficient alternative to economical photovoltaic devices, and the highest efficiency record has ...increased from ∼7% to ∼14%. To be more competitive in the solar cell markets, various organic materials are investigated and used in DSSCs to improve the cell efficiency, enhance the cell durability, and reduce the cost of production. In this review article, we provide a short review on the organic materials used for the preparation of photoanodes (including metal element-free organic dye sensitizers), quasi/all-solid-state electrolytes, and metal element-free electrocatalytic films in DSSCs with the cell efficiencies of >5%. Finally, the future perspectives for DSSCs are also briefly discussed.
•Assess the causal relation among oil price, geopolitical risk, and green bond index.•Use Granger-causality in quantile from December 2013 to January 2019 in the U.S.•Find unidirectional causality ...from geopolitical risk to oil price at the extreme tails.•Support bi-directional lower-tail causality from oil price to green bond index.•Present causality from geopolitical risk to green bond index in the lower quantiles.
This research explores the causal relation among oil price, geopolitical risks, and green bond index in the United States from December 2013 to January 2019. Unlike the conventional linear model specification used in earlier works, we evaluate causal relations based on Granger-causality in quantile analysis. Our empirical results reveal unidirectional Granger-causality from geopolitical risk to oil price at the extreme quantiles. We also observe a significant bi-directional causality from oil price to green bond index for the lower quantiles. Findings also reveal causality from geopolitical risk to green bond index in the lower quantiles of the distribution. Therefore, knowledge of these causal relationships can help policy makers to evaluate and implement effective policies to prevent sudden and substantial oil price shocks and geopolitical risk.
Coronavirus disease (COVID‐19) has already devastated the world, and the economy becomes the most critical challenge for any country worldwide. The increasing uncertainty of the COVID‐19 outbreak has ...made stock markets in China more turbulent and less predictable. Under the current exceptional circumstances, the hospitality industry suffered the most due to the travel restrictions. This research thus assesses the dynamic relationship among the COVID‐19 outbreak, macroeconomic fluctuations and hospitality stock returns based on a structural VAR framework from 13 January to 11 May 2020, in China. Evidence reveals that macroeconomic fluctuations and hospitality stock returns are significantly affected by shocks from the COVID‐19 outbreak. An unanticipated positive change of the COVID‐19 explosion triggers an addition in exchange rates and causes a reduction in the stock market and hospitality industry returns. For the impacts of the exchange rate, findings reveal that a surprise increase in exchange rates (currency depreciation) exerts a significant negative influence on stock market returns. Additionally, a positive change of stock market returns is linked to a decline in exchange rates and a rise in hospitality industry returns. Therefore, knowledge of these relationships can enable policymakers to evaluate and implement effective policies to stabilize the stock markets and help investors to make appropriate investment strategies.
While the literature has explored various determinants of energy poverty (EP), there is scant knowledge about the linkage between renewable energy technology (RET) innovation and EP. Based on an ...evaluation index system of energy poverty, this research applies the method of moment quantile regression model to examine whether and how RET innovation affects EP. Using panel data from China's 30 provinces for the 2003–2019 period, the results first reveal that RET innovation does relieve EP. Second, both linear and nonlinear models confirm that climate risk exhibits both a moderating effect and threshold effect on the relationship between them. When the climate risk index is low, RET innovation is conducive to the alleviation of EP; otherwise, the opposite is true. Finally, this moderating effect shows obvious spatial heterogeneity that only exists in western China and is not significant in the central and eastern region. Our findings thus enrich the extant literature and provide insights into targeted energy poverty reduction and achieving sustainable energy development.
•We study whether and how RET innovation affects energy poverty (EP).•The moderating effect and threshold effect of climate risk is further considered.•Results show that RET has an important influence on relieving EP.•Climate risk exhibits a regulatory effect on the relationship between RET and EP.•The greater the climate risk is, the more it can hinder RET to reduce EP
Nanoparticles have been studied as promising agents to reduce interfacial tension (IFT) and contact angle, which are two main mechanisms for enhanced oil recovery (EOR). Despite their advantages, the ...nanoparticles tend to agglomerate due to the drastic conditions of the reservoir, i.e., high temperature and/or high concentration of electrolytes, which lead to their separation from the oil/water interface and subsequent retention in a porous medium. Dielectric nanoparticles, as a suitable replacement for environmentally sensitive chemical EOR, had been proposed due to their thermal properties including high melting point. But more notably, these nanoparticles, coupled with low frequency electromagnetic (EM) waves, can be polarized to create disturbances at the oil/nanofluid interface, such that oil can be released from the reservoir rock surfaces and easily moved to the production well. However, the knowledge of nanoparticles’ characteristics (including morphology and dielectric properties) corresponding to different calcination temperatures that influence the recovery mechanism is still insufficient. For this purpose, dielectric nanofluids were prepared in brine with SDBS as a dispersant, using as-synthesized zinc- (ZnO) and aluminum-oxide (Al2O3) with an average crystallite size of 43.4–47.3 nm and 25–94.3 nm, respectively. Upon the measurement of the IFT of the crude oil/nanofluids system, it was shown that the rotational polarization, which depends on the dielectric loss of nanoparticles, was the major contributor to the enhanced interfacial disturbance through oil droplet deformation. These results have revealed a potential way to improve the oil displacement mechanism by employing the dielectric nanofluids under an EM field.
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Dye-sensitized solar cell (DSSC) is one of the third generation solar cells converting solar light into electricity that attracted a remarkable research interest globally due to their ...simple device fabrication processes in ambient conditions and reasonable cell efficiency for commercialization; moreover, the advantages on colorfulness, possible plasticity, and high conversion efficiencies under indoor illumination also render DSSC to play a crucial role in energy-harvesting systems for green buildings. To eliminate the electrolyte leakage issues in traditional DSSCs (i.e., cells with organic solvent-based electrolytes), new class of ionic liquids, namely poly(ionic liquid)s, are recently investigated and used as the quasi/all–solid state electrolyte to improve the cell durability. Herein, we give a short review on the poly(ionic liquid)s to be used as the quasi/all–solid state electrolytes in DSSCs. Finally, the future perspectives for the development of poly(ionic liquid)s for DSSCs are also briefly discussed.
Emerging evidence suggests that integrated care models are associated with improved mental health care access and outcomes for youths (children ≤12 years and adolescents 12-21 years) served in ...pediatric primary care settings. However, the key components of these complex models remain unexamined.
To identify and describe the key components of effective pediatric integrated mental health care models.
The PubMed, Embase, PsycINFO, and Cochrane Controlled Register of Trials electronic databases were searched for relevant peer-reviewed articles published between January 1, 1985, and April 30, 2019. Articles were restricted to those published in the English language. Eligible articles reported original data on youths 17 years or younger, implemented an integrated mental health care model in a pediatric primary care setting, and assessed the model's association with primary outcomes (eg, mental health symptom severity) and secondary outcomes (eg, functional impairment and patient satisfaction). Articles that specified some degree of systematic coordination or collaboration between primary care and mental health professionals were included in the final review. Two independent reviewers extracted data on study design, model type, model components, level of integration, and outcomes. Study quality was assessed using the Jadad scale. Data were analyzed between January 1, 2018, and May 31, 2019.
Eleven randomized clinical trials involving 2190 participants were included. Three studies focused on youths with depression, 3 on youths with attention-deficit/hyperactivity disorder, and 5 on youths with behavioral disorders. Most studies (9 of 11) implemented either the collaborative care model (n = 3), a slightly modified version of the collaborative care model (n = 2), or colocated care (n = 4). The most commonly reported components of effective pediatric integrated mental health care models were population-based care, measurement-based care, and delivery of evidence-based mental health services; all 3 components were present in studies reporting clinical improvement of mental health symptoms. Other model components, such as treatment-to-target or team-based care, were common in studies reporting specific outcomes, such as functional impairment.
This review is the first to date to systematically search and qualitatively synthesize information on the key components of effective pediatric integrated mental health care models. This knowledge may be especially useful for pediatric primary care administrators in the selection of an integrated care model for their setting.
Epithelial-mesenchymal transition (EMT)/mesenchymal-epithelial transition (MET) processes are proposed to be a driving force of cancer metastasis. By studying metastasis in bone marrow-derived ...mesenchymal stem cell (BM-MSC)-driven lung cancer models, microarray time-series data analysis by systems biology approaches revealed BM-MSC-induced signaling triggers early dissemination of CD133
/CD83
cancer stem cells (CSCs) from primary sites shortly after STAT3 activation but promotes proliferation towards secondary sites. The switch from migration to proliferation was regulated by BM-MSC-secreted LIF and activated LIFR/p-ERK/pS727-STAT3 signaling to promote early disseminated cancer cells MET and premetastatic niche formation. Then, tumor-tropic BM-MSCs circulated to primary sites and triggered CD151
/CD38
cells acquiring EMT-associated CSC properties through IL6R/pY705-STAT3 signaling to promote tumor initiation and were also attracted by and migrated towards the premetastatic niche. In summary, STAT3 phosphorylation at tyrosine 705 and serine 727 differentially regulates the EMT-MET switch within the distinct molecular subtypes of CSCs to complete the metastatic process.
Background
Our aim is to investigate the physiological relevance of the intestinal microbiota in alcohol‐induced liver injury. Chronic alcohol abuse is associated with intestinal bacterial ...overgrowth, increased intestinal permeability, and translocation of microbial products from the intestine to the portal circulation and liver. Translocated microbial products contribute to experimental alcoholic liver disease.
Methods
We subjected germ‐free and conventional C57BL/6 mice to a model of acute alcohol exposure that mimics binge drinking.
Results
Germ‐free mice showed significantly greater liver injury and inflammation after oral gavage of ethanol (EtOH) compared with conventional mice. In parallel, germ‐free mice exhibited increased hepatic steatosis and up‐regulated expression of genes involved in fatty acid and triglyceride synthesis compared with conventional mice after acute EtOH administration. The absence of microbiota was also associated with increased hepatic expression of EtOH‐metabolizing enzymes, which led to faster EtOH elimination from the blood and lower plasma EtOH concentrations. Intestinal levels of EtOH‐metabolizing genes showed regional expression differences and were overall higher in germ‐free mice relative to conventional mice.
Conclusions
Our findings indicate that absence of the intestinal microbiota increases hepatic EtOH metabolism and the susceptibility to binge‐like alcohol drinking.
This study demonstrates that germ‐free mice are more susceptible to acute alcohol‐induced liver injury. The commensal microbiota is important for promoting normal liver function in the face of acute injury. The observed phenotype in germ‐free mice is likely caused by a combination of three factors, involving increases in the production of alcohol‐derived toxic metabolites, steatosis, and inflammation.
Dye-sensitized solar cells (DSSCs) are fabricated using low-cost materials and a simple fabrication process; these advantages make them attractive candidates for research on next generation solar ...cells. In this type of solar cell, dye-sensitized metal oxide electrodes play an important role for achieving high performance since the porous metal oxide films provide large specific surface area for dye loading and the dye molecule possesses broad absorption covering the visible region or even part of the near-infrared (NIR). Recently, metal-free sensitizers have made great progress and become the most potential alternatives. This review mainly focuses on recent progress in metal-free sensitizers for applications in DSSCs. Besides, we also briefly report DSSCs with near-infrared (NIR) organic sensitizers, which provide the possibility to extend the absorption threshold of the sensitizers in the NIR region. Finally, special consideration has been paid to panchromatic engineering, co-sensitization, a key technique to achieve whole light absorption for improving the performance of DSSCs.
This review focuses on recent progress of metal-free sensitizers and on panchromatic engineering of co-sensitization in dye-sensitized solar cells (DSSCs).
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