Surfaces and heterojunction interfaces, where defects and energy levels dictate charge‐carrier dynamics in optoelectronic devices, are critical for unlocking the full potential of perovskite ...semiconductors. In this progress report, chemical structures of perovskite surfaces are discussed and basic physical rules for the band alignment are summarized at various perovskite interfaces. Common perovskite surfaces are typically decorated by various compositional and structural defects such as residual surface reactants, discrete nanoclusters, reactions by products, vacancies, interstitials, antisites, etc. Some of these surface species induce deep‐level defect states in the forbidden band forming very harmful charge‐carrier traps and affect negatively the interface band alignments for achieving optimal device performance. Herein, an overview of research progresses on surface and interface engineering is provided to minimize deep‐level defect states. The reviewed subjects include selection of interface and substrate buffer layers for growing better crystals, materials and processing methods for surface passivation, the surface catalyst for microstructure transformations, organic semiconductors for charge extraction or injection, heterojunctions with wide bandgap perovskites or nanocrystals for mitigating defects, and electrode interlayer for preventing interdiffusion and reactions. These surface and interface engineering strategies are shown to be critical in boosting device performance for both solar cells and light‐emitting diodes.
Recent progress on perovskite surface and interface science of perovskite optoelectronic devices is summarized. The impact of various surface and interface defects on heterojunction energy barriers and carrier dynamics in devices is reviewed and discussed. Practical engineering methods to mitigate these defects at various interfaces in devices are also considered.
Platinum (Pt)‐based catalysts with high Pt utilization efficiency for efficient H2 evolution are attracting extensive attention to meet the issues of energy exhaustion and environmental pollution. ...Herein, a one‐step electrochemical method is demonstrated to construct ultrafine heterostructure Pt2W/WO3 on reduced graphene oxide (RGO) by injecting multielectrons into the Preyssler anion NaP5W30O11014− to codeposit with anodic deliquescent Pt cations. The resulting Pt2W/WO3/RGO shows much higher performance than that of commercial Pt catalysts for large‐current‐density H2 evolution, which can deliver a large current density of 500 mA cm−2 with an overpotential of only 394 mV, much lower than that of 20% Pt/C (578 mV). Comparisons with control experiments and density functional theory (DFT) calculations both suggest that the much enhanced activity can be mainly attributed to the synergistic cooperation of different components to drive fast and continuous hydrogen desorption on Pt2W/WO3/RGO, while it could not run normally for 20% Pt/C under similar conditions due to the formation of huge bubbles on the electrode surface. The effective integration of high catalytic activity and hydrogen desorption ability into a single material can yield advanced materials for large‐current‐density H2 evolution with remarkable stability.
A polyoxometalate‐derived ultrafine heterostructure Pt2W/WO3
is constructed via a one‐step electrochemical codeposition process. This heterostructure can act as an efficient hydrogen evolution reaction (HER) electrocatalyst with performance that can significantly outperform platinum for large‐current‐density H2 evolution. The effective integration of high catalytic activity and hydrogen desorption ability into a single material represents a promising way to yield advanced materials for large‐current‐density H2 evolution.
METTL3 is known to be involved in all stages in the life cycle of RNA. It affects the tumor formation by the regulation the m6A modification in the mRNAs of critical oncogenes or tumor suppressors. ...In bladder cancer, METTL3 could promote the bladder cancer progression via AFF4/NF-κB/MYC signaling network by an m6A dependent manner. Recently, METTL3 was also found to affect the m6A modification in non-coding RNAs including miRNAs, lincRNAs and circRNAs. However, whether this mechanism is related to the proliferation of tumors induced by METTL3 is not reported yet.
Quantitative real-time PCR, western blot and immunohistochemistry were used to detect the expression of METTL3 in bladder cancer. The survival analysis was adopted to explore the association between METTL3 expression and the prognosis of bladder cancer. Bladder cancer cells were stably transfected with lentivirus and cell proliferation and cell cycle, as well as tumorigenesis in nude mice were performed to assess the effect of METTL3 in bladder cancer. RNA immunoprecipitation (RIP), co-immunoprecipitations and RNA m6A dot blot assays were conducted to confirm that METTL3 interacted with the microprocessor protein DGCR8 and modulated the pri-miR221/222 process in an m6A-dependent manner. Luciferase reporter assay was employed to identify the direct binding sites of miR221/222 with PTEN. Colony formation assay and CCK8 assays were conducted to confirm the function of miR-221/222 in METTL3-induced cell growth in bladder cancer.
We confirmed the oncogenic role of METTL3 in bladder cancer by accelerating the maturation of pri-miR221/222, resulting in the reduction of PTEN, which ultimately leads to the proliferation of bladder cancer. Moreover, we found that METTL3 was significantly increased in bladder cancer and correlated with poor prognosis of bladder cancer patients.
Our findings suggested that METTL3 may have an oncogenic role in bladder cancer through interacting with the microprocessor protein DGCR8 and positively modulating the pri-miR221/222 process in an m6A-dependent manner. To our knowledge, this is the first comprehensive study that METTL3 affected the tumor formation by the regulation the m6A modification in non-coding RNAs, which might provide fresh insights into bladder cancer therapy.
Perovskite light-emitting diodes (PeLEDs) have shown excellent performance in the green and near-infrared spectral regions, with high color purity, efficiency, and brightness. In order to shift the ...emission wavelength to the blue, compositional engineering (anion mixing) and quantum-confinement engineering (reduced-dimensionality) have been employed. Unfortunately, LED emission profiles shift with increasing driving voltages due to either phase separation or the coexistence of multiple crystal domains. Here we report color-stable sky-blue PeLEDs achieved by enhancing the phase monodispersity of quasi-2D perovskite thin films. We selected cation combinations that modulate the crystallization and layer thickness distribution of the domains. The perovskite films show a record photoluminescence quantum yield of 88% at 477 nm. The corresponding PeLEDs exhibit stable sky-blue emission under high operation voltages. A maximum luminance of 2480 cd m
at 490 nm is achieved, fully one order of magnitude higher than the previous record for quasi-2D blue PeLEDs.
The liver is essential for survival due to its critical role in the regulation of metabolic homeostasis.Metabolism of xenobiotics,such as environmental chemicals and drugs by the liver protects us ...from toxic effects of these xenobiotics,whereas metabolism of cholesterol,bile acids(BAs),lipids,and glucose provide key building blocks and nutrients to promote the growth or maintain the survival of the organism.As a wellestablished master regulator of liver development and function,hepatocyte nuclear factor 4 alpha(HNF4α)plays a critical role in regulating a large number of key genes essential for the metabolism of xenobiotics,metabolic wastes,and nutrients.The expression and activity of HNF4α is regulated by diverse hormonal and signaling pathways such as growth hormone,glucocorticoids,thyroid hormone,insulin,transforming growth factor-β,estrogen,and cytokines.HNF4α appears to play a central role in orchestrating the transduction of extracellular hormonal signaling and intracellular stress/nutritional signaling onto transcriptional changes in the liver.There have been a few reviews on the regulation of drug metabolism,lipid metabolism,cell proliferation,and inflammation by HNF4α.However,the knowledge on how the expression and transcriptional activity of HNF4α is modulated remains scattered.Herein I provide comprehensive review on the regulation of expression and transcriptional activity of HNF4α,and how HNF4α crosstalks with diverse extracellular and intracellular signaling pathways to regulate genes essential in liver pathophysiology.
A patient's infectivity is determined by the presence of the virus in different body fluids, secretions, and excreta. The persistence and clearance of viral RNA from different specimens of patients ...with 2019 novel coronavirus disease (COVID-19) remain unclear. This study analyzed the clearance time and factors influencing 2019 novel coronavirus (2019-nCoV) RNA in different samples from patients with COVID-19, providing further evidence to improve the management of patients during convalescence.
The clinical data and laboratory test results of convalescent patients with COVID-19 who were admitted to from January 20, 2020 to February 10, 2020 were collected retrospectively. The reverse transcription polymerase chain reaction (RT-PCR) results for patients' oropharyngeal swab, stool, urine, and serum samples were collected and analyzed. Convalescent patients refer to recovered non-febrile patients without respiratory symptoms who had two successive (minimum 24 h sampling interval) negative RT-PCR results for viral RNA from oropharyngeal swabs. The effects of cluster of differentiation 4 (CD4)+ T lymphocytes, inflammatory indicators, and glucocorticoid treatment on viral nucleic acid clearance were analyzed.
In the 292 confirmed cases, 66 patients recovered after treatment and were included in our study. In total, 28 (42.4%) women and 38 men (57.6%) with a median age of 44.0 (34.0-62.0) years were analyzed. After in-hospital treatment, patients' inflammatory indicators decreased with improved clinical condition. The median time from the onset of symptoms to first negative RT-PCR results for oropharyngeal swabs in convalescent patients was 9.5 (6.0-11.0) days. By February 10, 2020, 11 convalescent patients (16.7%) still tested positive for viral RNA from stool specimens and the other 55 patients' stool specimens were negative for 2019-nCoV following a median duration of 11.0 (9.0-16.0) days after symptom onset. Among these 55 patients, 43 had a longer duration until stool specimens were negative for viral RNA than for throat swabs, with a median delay of 2.0 (1.0-4.0) days. Results for only four (6.9%) urine samples were positive for viral nucleic acid out of 58 cases; viral RNA was still present in three patients' urine specimens after throat swabs were negative. Using a multiple linear regression model (F = 2.669, P = 0.044, and adjusted R = 0.122), the analysis showed that the CD4+ T lymphocyte count may help predict the duration of viral RNA detection in patients' stools (t = -2.699, P = 0.010). The duration of viral RNA detection from oropharyngeal swabs and fecal samples in the glucocorticoid treatment group was longer than that in the non-glucocorticoid treatment group (15 days vs. 8.0 days, respectively; t = 2.550, P = 0.013) and the duration of viral RNA detection in fecal samples in the glucocorticoid treatment group was longer than that in the non-glucocorticoid treatment group (20 days vs. 11 days, respectively; t = 4.631, P < 0.001). There was no statistically significant difference in inflammatory indicators between patients with positive fecal viral RNA test results and those with negative results (P > 0.05).
In brief, as the clearance of viral RNA in patients' stools was delayed compared to that in oropharyngeal swabs, it is important to identify viral RNA in feces during convalescence. Because of the delayed clearance of viral RNA in the glucocorticoid treatment group, glucocorticoids are not recommended in the treatment of COVID-19, especially for mild disease. The duration of RNA detection may relate to host cell immunity.
Future wearable technologies and personal electronics may benefit from e‐textiles that simultaneously possess high elasticity and multiple capabilities such as energy harvesting and sensing. Here, ...the first elastic multifunctional fiber that can scavenge mechanical energy from body motion and electromagnetic energy from surrounding electrical appliances is presented. In addition to converting multiple sources of waste energy into electricity, the fibers can also serve as self‐powered tactile and biomechanical sensors. The fibers consist of hollow elastomeric fibers filled with liquid metal. The fibers harvest energy by the combination of triboelectricity (160 V m−1, 5 µA m−1, and ≈360 µW m−1) and induced electrification of the liquid metal (±8 V m−1 (60 Hz), ±1.4 µA m−1, and ≈8 µW m−1). The fibers are characterized and their utility for powering electronics and sensing biomechanical information is demonstrated. These fibers are further demonstrated as completely soft and stretchable components for human–machine interfaces, including keypads and wireless music controllers.
Inherently stretchable (>650%) and elastic multifunctional liquid‐metal fibers that can scavenge biomechanical and electromagnetic energy are developed as wearable power providers and self‐powered sensors. These findings optimally unify mechanical freedom and the capability of collecting multiple forms of ambient energy and self‐powered sensing in a single fiber, opening new doors for wearable/stretchable energy and sensing technologies.
Globally there are mounting concerns about nurses’ job satisfaction because of its pivotal role in nurse turnover and the quality of care of patients.
To identify a more comprehensive and extensive ...knowledge of the job satisfaction of qualified general nurses working in acute care hospitals and its associated factors drawing upon empirical literature published in the last five years.
Literature review.
A comprehensive electronic database search was conducted in PubMed (2012–2017), Web of Science (2012–2017), CINAHL (2012–2017), Embase (2012–2017), PsycINFO (2012–2017) and the Applied Social Sciences Index (2012–2017), CNKI (2012–2017), WanFang (2012–2017), SinoMed (2012–2017) and VIP (2012–2017) to retrieve relevant articles published in both English and Chinese between January 2012 and October 2017.
Key terms and phrases associated with job satisfaction, occupational stress, professional commitment, role conflict and role ambiguity were utilized in the subject search in combination with nurses following guidelines for searching the OVID interface. The abstracts or full texts of research papers were reviewed prior to their inclusion in the review according to inclusion criteria and quality assessment using the Strobe guidelines.
A total of 59 papers were included in this review. The impact of job satisfaction upon sickness absence, turnover intention, as well as the influencing factors of job satisfaction such as working shift and leadership, job performance, organizational commitment, effort and reward style has been identified in a number of research studies yielding equivocal findings. Job satisfaction of hospital nurses is closely related to work environment, structural empowerment, organizational commitment, professional commitment, job stress, patient satisfaction, patient-nurse ratios, social capital, evidence-based practice and ethnic background. Various mediating or moderating pathways have been identified with nurses’ job satisfaction being mediated by various factors.
It is vital to increase nurses’ job satisfaction because this has the potential both to improve patients' perceptions of care quality and ensure an adequate nursing workforce. The indirect relationships and predictors of job satisfaction contribute to a more comprehensive understanding of the complex phenomenon of job satisfaction, which in turn may aid the development of effective strategies to address the nursing shortage and increase the quality of patient care.
An electroactive room‐temperature phosphorescence (RTP) polymer has been demonstrated based on a characteristic donor‐oxygen‐acceptor geometry. Compared with the donor–acceptor reference, the ...inserted oxygen atom between donor and acceptor can not only decrease hole‐electron orbital overlap to suppress the charge transfer fluorescence, but also strengthen spin‐orbital coupling effect to facilitate the intersystem crossing and subsequent phosphorescence channels. As a result, a significant RTP is observed in solid states under photo excitation. Most noticeably, the corresponding polymer light‐emitting diodes (PLEDs) reveal a dominant electrophosphorescence with a record‐high external quantum efficiency of 9.7 %. The performance goes well beyond the 5 % theoretical limit for typical fluors, opening a new door to the development of pure organic RTP polymers towards efficient PLEDs.
A donor‐oxygen‐acceptor geometry has been demonstrated for the design of electroactive pure organic room‐temperature phosphorescence polymers, whose PLEDs achieve a promising EQE of 9.7 %.
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