Ammonia is synthesized directly from water and N2 at room temperature and atmospheric pressure in a flow electrochemical cell operating in gas phase (half‐cell for the NH3 synthesis). Iron supported ...on carbon nanotubes (CNTs) was used as the electrocatalyst in this half‐cell. A rate of ammonia formation of 2.2×10−3 gNH3
m−2 h−1 was obtained at room temperature and atmospheric pressure in a flow of N2, with stable behavior for at least 60 h of reaction, under an applied potential of −2.0 V. This value is higher than the rate of ammonia formation obtained using noble metals (Ru/C) under comparable reaction conditions. Furthermore, hydrogen gas with a total Faraday efficiency as high as 95.1 % was obtained. Data also indicate that the active sites in NH3 electrocatalytic synthesis may be associated to specific carbon sites formed at the interface between iron particles and CNT and able to activate N2, making it more reactive towards hydrogenation.
Sustainable industrial chemistry: Ammonia is synthesized directly from water and N2 at room temperature and atmospheric pressure in an electrochemical flow cell operating in the gas phase (half‐cell for NH3 synthesis). Iron supported on carbon nanotubes was used as the electrocatalyst in this half‐cell.
RuO2 is considered as the state‐of‐the‐art electrocatalyst for the oxygen evolution reaction (OER) in acidic media. However, its practical application is largely hindered by both the high reaction ...overpotential and severe electrochemical corrosion of the active centers. To overcome these limitations, innovative design strategies are necessary, which remains a great challenge. Herein, robust interface Ru centers between RuO2 and graphene, via a controllable oxidation of graphene encapsulating Ru nanoparticles, are presented to efficiently enhance both the activity and stability of the acidic OER. Through precisely controlling the reaction interface, a much lower OER overpotential of only 227 mV at 10 mA cm−2 in acidic electrolyte, compared with that of 290 mV for commercial RuO2, but a significantly higher durability than the commercial RuO2, are achieved. Density functional theory (DFT) calculations reveal that the interface Ru centers between the RuO2 and the graphene can break the classic scaling relationships between the free energies of HOO* and HO* to reduce the limiting potential, rendering an enhancement in the intrinsic OER activity and the resistance to over‐oxidation and corrosion for RuO2.
The robust interface Ru centers between RuO2 and graphene are found to boost both activity and stability for the acidic oxygen evolution reaction (OER), exhibiting a much lower OER overpotential of only 227 mV at 10 mA cm−2 compared with that of 290 mV for commercial RuO2 but a significantly higher durability than the commercial RuO2.
In this paper, a new 4D smooth chaotic system with coexisting attractors is proposed. The coexisting attractors which means two or more attractors generate simultaneously from different initial ...values is an important nonlinear dynamics. It is found that the new system is rich in coexisting attractors by numerical simulation. Detailed investigation of the coexisting chaotic attractors, coexisting chaotic and periodic attractors, coexisting chaotic and point attractors, coexisting periodic and point attractors in the system are presented. It is shown that the system may coexist four independent attractors by selecting appropriate parameters and initial values.
The vertebrate retina is made up of six specialized neuronal cell types and one glia that are generated from a common retinal progenitor. The development of these distinct cell types is programmed by ...transcription factors that regulate the expression of specific genes essential for cell fate specification and differentiation. Because of the complex nature of transcriptional regulation, understanding transcription factor functions in development and disease is challenging. Research on the
transcription factor CRX provides an excellent model to address these challenges. In this review, we reflect on 25 years of mammalian CRX research and discuss recent progress in elucidating the distinct pathogenic mechanisms of four
coding variant classes. We highlight how
biochemical studies of CRX protein functions facilitate understanding CRX regulatory principles in animal models. We conclude with a brief discussion of the emerging systems biology approaches that could accelerate precision medicine for
-linked diseases and beyond.
Sb2Se3 thin films prepared by vapor transport deposition (VTD) method have been treated by post annealing process at 200 °C in vacuum condition for 1 h, and the comparative studies between the post ...annealing treatment (PAT) and without the treatment were carried out. The device efficiency was improved from 4.89% to 5.72% by PAT via the augment of open-circuit voltage and fill factor. Electrical properties from dark J-V and C-V measurements, structural properties from X-ray diffraction, Raman and scanning electron microscope measurements, defect properties from admittance measurements have been compared for the two cell samples. The Sb2Se3 cell sample with PAT was found to own less parallel current pathways, larger built-in voltage, better crystalline and lower defects densities, which may account for the efficiency enhancement.
•Efficiency of Sb2Se3 solar cells was improved from 4.89% to 5.72% by post annealing treatment (PAT) in vacuum condition.•Improved Sb2Se3 cell owns less parallel current pathways, larger built-in voltage, better crystalline and less defects.•The augment of open circuit voltage could be mainly attributed to the increase of built-in voltage.
Photoreceptor development of the vertebrate visual system is controlled by a complex transcription regulatory network. OTX2 is expressed in the mitotic retinal progenitor cells (RPCs) and controls ...photoreceptor genesis. CRX that is activated by OTX2 is expressed in photoreceptor precursors after cell cycle exit. NEUROD1 is also present in photoreceptor precursors that are ready to specify into rod and cone photoreceptor subtypes. NRL is required for the rod fate and regulates downstream rod-specific genes including the orphan nuclear receptor NR2E3 which further activates rod-specific genes and simultaneously represses cone-specific genes. Cone subtype specification is also regulated by the interplay of several transcription factors such as THRB and RXRG. Mutations in these key transcription factors are responsible for ocular defects at birth such as microphthalmia and inherited photoreceptor diseases such as Leber congenital amaurosis (LCA), retinitis pigmentosa (RP) and allied dystrophies. In particular, many mutations are inherited in an autosomal dominant fashion, including the majority of missense mutations in
and
. In this review, we describe the spectrum of photoreceptor defects that are associated with mutations in the above-mentioned transcription factors, and summarize the current knowledge of molecular mechanisms underlying the pathogenic mutations. At last, we deliberate the outstanding gaps in our understanding of the genotype-phenotype correlations and outline avenues for future research of the treatment strategies.
Abstract
Considering the real-world scenarios that there are interactions between edges in different networks and each network has different topological structure and size, we introduce a model of ...interdependent networks with arbitrary edge-coupling strength, in which
q
A
and
q
B
are used to represent the edge-coupling strength of network
A
and network
B
respectively. A mathematical framework using generating functions is developed based on self-consistent probabilities approach, which is verified by computer simulations. In particular, we carry out this mathematical framework on the Erdös–Rényi edge-coupled interdependent networks to calculate the values of phase transition thresholds and the critical coupling strengths which distinguish different types of transitions. Moreover, as contrast to the corresponding node-coupled interdependent networks, we find that for edge-coupled interdependent networks the critical coupling strengths are smaller, and the critical thresholds as well, which means the robustness of partially edge-coupled interdependent networks is better than that of partially node-coupled interdependent networks. Furthermore, we find that network
A
will have hybrid percolation behaviors as long as the coupling strength
q
A
belongs to a certain range, and the range does not affected by average degree of network
A
. Our findings may fill the gap of understanding the robustness of edge-coupled interdependent networks with arbitrary coupling strength, and have significant meaning for network security design and optimization.
Enhancers function with a basal promoter to control the transcription of target genes. Enhancer regulatory activity is often studied using reporter-based transgene assays. However, unmatched results ...have been reported when selected enhancers are silenced in situ. In this study, using genomic deletion analysis in mice, we investigated the roles of two previously identified enhancers and the promoter of the Rho gene that codes for the visual pigment rhodopsin. The Rho gene is robustly expressed by rod photoreceptors of the retina, and essential for the subcellular structure and visual function of rod photoreceptors. Mutations in RHO cause severe vision loss in humans. We found that each Rho regulatory region can independently mediate local epigenomic changes, but only the promoter is absolutely required for establishing active Rho chromatin configuration and transcription and maintaining the cell integrity and function of rod photoreceptors. To our surprise, two Rho enhancers that enable strong promoter activation in reporter assays are largely dispensable for Rho expression in vivo. Only small and age-dependent impact is detectable when both enhancers are deleted. Our results demonstrate context-dependent roles of enhancers and highlight the importance of studying functions of cis-regulatory regions in the native genomic context.
Hybrid organic–inorganic metal halide perovskites are currently arousing enthusiasm and stimulating huge activity across several fields of optoelectronics due to their outstanding properties. In this ...study, we present the incoherent random lasing (RL) emissions from CH3NH3PbBr3 perovskite thin films on both planar fluorine-doped tin oxide (FTO) substrates and patterned sapphire substrates (PSSs). A detailed examination of the spectral evolution indicates that inelastic exciton–exciton scattering called P-emission is the most plausible mechanism accounting for the lasing emissions. The RL threshold of the perovskite films on PSSs is found to be effectively reduced by more than one order of magnitude from 2.55 to 0.15 μJ per pulse compared to that on FTO substrates. The giant threshold reduction is ascribed to the enhanced random scattering of light and the photon recycling induced by the multireflection processes at the perovskite/PSS interface, which increases the likelihood that the inoperative random rays will re-enter the possible optical loops formed among the perovskite particles, resulting in considerable optical resonance enhancement. The simulation results reveal that the light extraction efficiency on the top facet of the perovskites is significantly increased by approximately 155% by utilizing the PSS instead of the FTO substrate. Moreover, the first direct experimental observation of the multireflection phenomenon of light, as well as the dynamic processes of photon propagation in the composite PSS structure, is presented by Kerr-gate-based time-resolved photoluminescence. Our results provide an effective strategy to achieve high-performance perovskite random lasers and novel light-emitting devices for speckle-free full-field imaging and solid-state lighting applications, by introducing ingeniously designed periodic nano-/microscale optical structures.
Abstract
Emerging discoveries of dynamic and reversible N6-methyladenosine (m
6
A) modification on RNA in mammals have revealed the key roles of the modification in human tumorigenesis. As known m
6
...A readers, insulin-like growth factor 2 mRNA-binding proteins (IGF2BPs) are upregulated in most cancers and mediates the enhancement of m
6
A-modified mRNAs stability. However, the mechanisms of IGF2BPs in renal cell cancer (RCC) still remain unclear. Bioinformatic analysis and RT-qPCR were performed to evaluate the expression of IGF2BPs and m
6
A writer Wilms tumor 1-associating protein (WTAP) in RCC samples and its correlation with patient prognosis. In vitro, in vivo biological assays were performed to investigate the functions of IGF2BPs and WTAP in RCC. Chromatin immunoprecipitation-qPCR (ChIP-qPCR) combined with bioinformatics analysis and following western blot assay, dual-luciferase reporter assays were performed to validate the regulatory relationships between transcription factor (TF) early growth response 2 (EGR2) and potential target genes IGF2BPs. RNA sequencing (RNA-seq), methylated RNA immunoprecipitation-qPCR (MERIP-qPCR), RIP-qPCR, m
6
A dot blot, and dual-luciferase reporter assays combined with bioinformatics analysis were employed to screen and validate the direct targets of IGF2BPs and WTAP. Here, we showed that early growth response 2 (EGR2) transcription factor could increase IGF2BPs expression in RCC. IGF2BPs in turn regulated sphingosine-1-phosphate receptor 3 (S1PR3) expression in an m
6
A-dependent manner by enhancing the stability of S1PR3 mRNA. They also promoted kidney tumorigenesis via PI3K/AKT pathway. Furthermore, IGF2BPs and WTAP upregulation predicted poor overall survival in RCC. Our studies showed that the EGR2/IGF2BPs regulatory axis and m
6
A-dependent regulation of S1PR3-driven RCC tumorigenesis, which enrich the m
6
A-modulated regulatory network in renal cell cancer. Together, our findings provide new evidence for the role of N6-methyladenosine modification in RCC.
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