Electroreduction of carbon dioxide (CO2) into high‐value and readily collectable liquid products is vital but remains a substantial challenge due to the lack of highly efficient and robust ...electrocatalysts. Herein, Bi‐based metal‐organic framework (CAU‐17) derived leafy bismuth nanosheets with a hybrid Bi/BiO interface (Bi NSs) is developed, which enables CO2 reduction to formic acid (HCOOH) with high activity, selectivity, and stability. Specially, the flow cell configuration is employed to eliminate the diffusion effect of CO2 molecules and simultaneously achieve considerable current density (200 mA cm−2) for industrial application. The faradaic efficiency for transforming CO2 to HCOOH can achieve over 85 or 90% in 1 m KHCO3 or KOH for at least 10 h despite a current density that exceeds 200 mA cm−2, outperforming most of the reported CO2 electroreduction catalysts. The hybrid Bi/BiO surface of leafy bismuth nanosheets boosts the adsorption of CO2 and protects the surface structure of the as‐prepared leafy bismuth nanosheets, which benefits its activity and stability for CO2 electroreduction. This work shows that modifying electrocatalysts by surface oxygen groups is a promising pathway to regulate the activity and stability for selective CO2 reduction to HCOOH.
Herein, leafy bismuth nanosheets are shown to achieve CO2 electroreduction to HCOOH with high activity (>200 mA cm−2), selectivity (>90%) and stability (>10 h) by employing in gas diffusion cell configuration. According to the in‐depth characterizations, the large electrochemically accessible surface area and the superficial BiO species for Bi nanosheets are the key factors that enable the high catalytic activity.
Observation of chiral phonons Zhu, Hanyu; Yi, Jun; Li, Ming-Yang ...
Science (American Association for the Advancement of Science),
02/2018, Volume:
359, Issue:
6375
Journal Article
Peer reviewed
Open access
Chirality reveals symmetry breaking of the fundamental interaction of elementary particles. In condensed matter, for example, the chirality of electrons governs many unconventional transport ...phenomena such as the quantum Hall effect. Here we show that phonons can exhibit intrinsic chirality in monolayer tungsten diselenide. The broken inversion symmetry of the lattice lifts the degeneracy of clockwise and counterclockwise phonon modes at the corners of the Brillouin zone. We identified the phonons by the intervalley transfer of holes through hole-phonon interactions during the indirect infrared absorption, and we confirmed their chirality by the infrared circular dichroism arising from pseudoangular momentum conservation. The chiral phonons are important for electron-phonon coupling in solids, phonon-driven topological states, and energy-efficient information processing.
Rearrangement reactions have attracted considerable interest over the past decades due to their high bond-forming efficiency and atom economy in the construction of complex organic architectures. In ...contrast to the well-established 3,3-rearrangement, 1,3 O-to-C rearrangement has been far less vigorously investigated, and stereospecific 1,3-rearrangement is extremely rare. Here, we report a metal-free intramolecular hydroalkoxylation/1,3-rearrangement, leading to the practical and atom-economical assembly of various valuable medium-sized lactams with wide substrate scope and excellent diastereoselectivity. Moreover, such an asymmetric cascade cyclization has also been realized by chiral Brønsted acid-catalyzed kinetic resolution. In addition, biological tests reveal that some of these medium-sized lactams displayed their bioactivity as antitumor agents against melanoma cells, esophageal cancer cells and breast cancer cells. A mechanistic rationale for the reaction is further supported by control experiments and theoretical calculations.
As hot topics in the chemical conversion of CO2, the photo‐/electrocatalytic reduction of CO2 and use of CO2 as a supporter for energy storage have shown great potential for the utilization of CO2. ...However, many obstacles still exist on the road to realizing highly efficient chemical CO2 conversion, such as inefficient uptake/activation of CO2 and mass transport in catalysts. Covalent organic frameworks (COFs), as a kind of porous material, have been widely explored as catalysts for the chemical conversion of CO2 owing to their unique features. In particular, COF‐based functional materials containing diverse active sites (such as single metal sites, metal nanoparticles, and metal oxides) offer great potential for realizing CO2 conversion and energy storage. This Minireview discusses recent breakthroughs in the basic knowledge, mechanisms, and pathways of chemical CO2 conversion strategies that use COF‐based functional catalysts. In addition, the challenges and prospects of COF‐based functional catalysts for the efficient utilization of CO2 are also introduced.
This Minireview discusses recent developments in the basic knowledge, mechanisms, and CO2 utilization strategies regarding the use of functional materials based on covalent‐organic frameworks (COFs) with diverse active sites as catalysts. Insight is provided into the challenges and prospects of COF‐based catalysts for the design of the next‐generation photo‐/electrocatalysts for the utilization of CO2.
Studies of gene rearrangements and the consequent oncogenic fusion proteins have laid the foundation for targeted cancer therapy. To identify oncogenic fusions associated with glioma progression, we ...catalogued fusion transcripts by RNA-seq of 272 gliomas. Fusion transcripts were more frequently found in high-grade gliomas, in the classical subtype of gliomas, and in gliomas treated with radiation/temozolomide. Sixty-seven in-frame fusion transcripts were identified, including three recurrent fusion transcripts: FGFR3-TACC3, RNF213-SLC26A11, and PTPRZ1-MET (ZM). Interestingly, the ZM fusion was found only in grade III astrocytomas (1/13; 7.7%) or secondary GBMs (sGBMs, 3/20; 15.0%). In an independent cohort of sGBMs, the ZM fusion was found in three of 20 (15%) specimens. Genomic analysis revealed that the fusion arose from translocation events involving introns 3 or 8 of PTPRZ and intron 1 of MET. ZM fusion transcripts were found in GBMs irrespective of isocitrate dehydrogenase 1 (IDH1) mutation status. sGBMs harboring ZM fusion showed higher expression of genes required for PIK3CA signaling and lowered expression of genes that suppressed RB1 or TP53 function. Expression of the ZM fusion was mutually exclusive with EGFR overexpression in sGBMs. Exogenous expression of the ZM fusion in the U87MG glioblastoma line enhanced cell migration and invasion. Clinically, patients afflicted with ZM fusion harboring glioblastomas survived poorly relative to those afflicted with non-ZM-harboring sGBMs (P < 0.001). Our study profiles the shifting RNA landscape of gliomas during progression and reveled ZM as a novel, recurrent fusion transcript in sGBMs.
Catalysts and ligands possessing the great ability to tolerate over a wide range of mechanistically unrelated reactions are remarked as "privileged", which are rather scarce but extremely meaningful ...in asymmetric catalysis. Feng and co‐workers have developed a library of conformationally flexible, C2‐symmetric N,N'‐dioxide amide compounds with original design and featured structure (named as Feng ligand now). They were initially reported as chiral organocatalysts in 2005 and have been further developed as a new class of privileged chiral ligands since 2006. Tremendous success, including versatile coordination chemistry with plenty of metal sources (main‐group metals, transition metals, and rare‐earth metals), a truly broad scope of asymmetric reactions (more than 50 types), diverse areas of catalysis (organocatalysis, Lewis‐acid catalysis, bimetallic relay catalysis, and photocatalysis), numerous synthetic applications of bioactive compounds, has been achieved using Feng N,N'‐dioxide. Besides, they demonstrate that chiral ligands with conformationally flexible property can offer excellent chiral environment as well, which challenges the conventional idea preferring rigid structures in the design of chiral ligands. Herein, we briefly introduced the discovery of Feng ligand and the millstones during the development. We also covered the successful applications of Feng ligand by other scientists as well as novel chiral ligands inspired by them.
A Survey of Multi-View Representation Learning Li, Yingming; Yang, Ming; Zhang, Zhongfei
IEEE transactions on knowledge and data engineering,
10/2019, Volume:
31, Issue:
10
Journal Article
Peer reviewed
Open access
Recently, multi-view representation learning has become a rapidly growing direction in machine learning and data mining areas. This paper introduces two categories for multi-view representation ...learning: multi-view representation alignment and multi-view representation fusion. Consequently, we first review the representative methods and theories of multi-view representation learning based on the perspective of alignment, such as correlation-based alignment. Representative examples are canonical correlation analysis (CCA) and its several extensions. Then, from the perspective of representation fusion, we investigate the advancement of multi-view representation learning that ranges from generative methods including multi-modal topic learning, multi-view sparse coding, and multi-view latent space Markov networks, to neural network-based methods including multi-modal autoencoders, multi-view convolutional neural networks, and multi-modal recurrent neural networks. Further, we also investigate several important applications of multi-view representation learning. Overall, this survey aims to provide an insightful overview of theoretical foundation and state-of-the-art developments in the field of multi-view representation learning and to help researchers find the most appropriate tools for particular applications.
Since early December 2019, the 2019 novel coronavirus disease (COVID-19) has caused pneumonia epidemic in Wuhan, Hubei province of China. This study aimed to investigate the factors affecting the ...progression of pneumonia in COVID-19 patients. Associated results will be used to evaluate the prognosis and to find the optimal treatment regimens for COVID-19 pneumonia.
Patients tested positive for the COVID-19 based on nucleic acid detection were included in this study. Patients were admitted to 3 tertiary hospitals in Wuhan between December 30, 2019, and January 15, 2020. Individual data, laboratory indices, imaging characteristics, and clinical data were collected, and statistical analysis was performed. Based on clinical typing results, the patients were divided into a progression group or an improvement/stabilization group. Continuous variables were analyzed using independent samples t-test or Mann-Whitney U test. Categorical variables were analyzed using Chi-squared test or Fisher's exact test. Logistic regression analysis was performed to explore the risk factors for disease progression.
Seventy-eight patients with COVID-19-induced pneumonia met the inclusion criteria and were included in this study. Efficacy evaluation at 2 weeks after hospitalization indicated that 11 patients (14.1%) had deteriorated, and 67 patients (85.9%) had improved/stabilized. The patients in the progression group were significantly older than those in the disease improvement/stabilization group (66 51, 70 vs. 37 32, 41 years, U = 4.932, P = 0.001). The progression group had a significantly higher proportion of patients with a history of smoking than the improvement/stabilization group (27.3% vs. 3.0%, χ = 9.291, P = 0.018). For all the 78 patients, fever was the most common initial symptom, and the maximum body temperature at admission was significantly higher in the progression group than in the improvement/stabilization group (38.2 37.8, 38.6 vs. 37.5 37.0, 38.4°C, U = 2.057, P = 0.027). Moreover, the proportion of patients with respiratory failure (54.5% vs. 20.9%, χ = 5.611, P = 0.028) and respiratory rate (34 18, 48 vs. 24 16, 60 breaths/min, U = 4.030, P = 0.004) were significantly higher in the progression group than in the improvement/stabilization group. C-reactive protein was significantly elevated in the progression group compared to the improvement/stabilization group (38.9 14.3, 64.8 vs. 10.6 1.9, 33.1 mg/L, U = 1.315, P = 0.024). Albumin was significantly lower in the progression group than in the improvement/stabilization group (36.62 ± 6.60 vs. 41.27 ± 4.55 g/L, U = 2.843, P = 0.006). Patients in the progression group were more likely to receive high-level respiratory support than in the improvement/stabilization group (χ = 16.01, P = 0.001). Multivariate logistic analysis indicated that age (odds ratio OR, 8.546; 95% confidence interval CI: 1.628-44.864; P = 0.011), history of smoking (OR, 14.285; 95% CI: 1.577-25.000; P = 0.018), maximum body temperature at admission (OR, 8.999; 95% CI: 1.036-78.147, P = 0.046), respiratory failure (OR, 8.772, 95% CI: 1.942-40.000; P = 0.016), albumin (OR, 7.353, 95% CI: 1.098-50.000; P = 0.003), and C-reactive protein (OR, 10.530; 95% CI: 1.224-34.701, P = 0.028) were risk factors for disease progression.
Several factors that led to the progression of COVID-19 pneumonia were identified, including age, history of smoking, maximum body temperature at admission, respiratory failure, albumin, and C-reactive protein. These results can be used to further enhance the ability of management of COVID-19 pneumonia.
The recent development of 2D monolayer lateral semiconductor has created new paradigm to develop p‐n heterojunctions. Albeit, the growth methods of these heterostructures typically result in alloy ...structures at the interface, limiting the development for high‐efficiency photovoltaic (PV) devices. Here, the PV properties of sequentially grown alloy‐free 2D monolayer WSe2‐MoS2 lateral p‐n heterojunction are explores. The PV devices show an extraordinary power conversion efficiency of 2.56% under AM 1.5G illumination. The large surface active area enables the full exposure of the depletion region, leading to excellent omnidirectional light harvesting characteristic with only 5% reduction of efficiency at incident angles up to 75°. Modeling studies demonstrate the PV devices comply with typical principles, increasing the feasibility for further development. Furthermore, the appropriate electrode‐spacing design can lead to environment‐independent PV properties. These robust PV properties deriving from the atomically sharp lateral p‐n interface can help develop the next‐generation photovoltaics.
By sequential growth of alloy‐free 2D monolayer WSe2‐MoS2 lateral p‐n heterojunction, photovoltaic devices show extraordinary power conversion efficiencies of 2.56%. The large surface active area of the devices enables the full exposure of the depletion region, leading to excellent omnidirectional light harvesting characteristic. Modeling studies demonstrate the devices comply with typical principles. The appropriate electrode‐spacing design leads to environment‐independent properties.
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