Crystalline and porous covalent organic frameworks (COFs) and metal‐organic frameworks (MOFs) materials have attracted enormous attention in the field of photocatalytic H2 evolution due to their ...long‐range order structures, large surface areas, outstanding visible light absorbance, and tunable band gaps. In this work, we successfully integrated two‐dimensional (2D) COF with stable MOF. By covalently anchoring NH2‐UiO‐66 onto the surface of TpPa‐1‐COF, a new type of MOF/COF hybrid materials with high surface area, porous framework, and high crystallinity was synthesized. The resulting hierarchical porous hybrid materials show efficient photocatalytic H2 evolution under visible light irradiation. Especially, NH2‐UiO‐66/TpPa‐1‐COF (4:6) exhibits the maximum photocatalytic H2 evolution rate of 23.41 mmol g−1 h−1 (with the TOF of 402.36 h−1), which is approximately 20 times higher than that of the parent TpPa‐1‐COF and the best performance photocatalyst for H2 evolution among various MOF‐ and COF‐based photocatalysts.
Effective separation: A novel MOF/COF hybrid material assembled by covalent connecting two components, exhibits effective visible‐light‐driven photocatalytic H2 evolution due to the ideal band matching and effectively promoting the separation of the photogenerated charges and holes.
Fabrication of soft piezoelectric nanomaterials is essential for the development of wearable and implantable biomedical devices. However, a big challenge in this soft functional material development ...is to achieve a high piezoelectric property with long‐term stability in a biological environment. Here, a one‐step strategy for fabricating core/shell poly(vinylidene difluoride) (PVDF)/dopamine (DA) nanofibers (NFs) with a very high β‐phase content and self‐aligned polarization is reported. The self‐assembled core/shell structure is believed essential for the formation and alignment of β‐phase PVDF, where strong intermolecular interaction between the NH2 groups on DA and the CF2 groups on PVDF is responsible for aligning the PVDF chains and promoting β‐phase nucleation. The as‐received PVDF/DA NFs exhibit significantly enhanced piezoelectric performance and excellent stability and biocompatibility. An all‐fiber‐based soft sensor is fabricated and tested on human skin and in vivo in mice. The devices show a high sensitivity and accuracy for detecting weak physiological mechanical stimulation from diaphragm motions and blood pulsation. This sensing capability offers great diagnostic potential for the early assessment and prevention of cardiovascular diseases and respiratory disorders.
High‐performance poly(vinylidene difluoride)/dopamine core/shell piezoelectric nanofibers with excellent stability are successfully fabricated by one‐step electrospinning in large scale and quantity, offering an extraordinary building block for developing self‐powered sensor devices to detect weak absolute pressure change from soft tissues in vivo. This sensing capability offers great diagnostic potential for the early assessment and prevention of cardiovascular diseases and respiratory disorders.
To determine distribution of severe acute respiratory syndrome coronavirus 2 in hospital wards in Wuhan, China, we tested air and surface samples. Contamination was greater in intensive care units ...than general wards. Virus was widely distributed on floors, computer mice, trash cans, and sickbed handrails and was detected in air ≈4 m from patients.
Radical borylation using N‐heterocyclic carbene (NHC)‐BH3 complexes as boryl radical precursors has emerged as an important synthetic tool for organoboron assembly. However, the majority of reported ...methods are limited to reaction modes involving carbo‐ and/or hydroboration of specific alkenes and alkynes. Moreover, the generation of NHC‐boryl radicals relies principally on hydrogen atom ion with the aid of radical initiators. A distinct radical generation method is reported, as well as the reaction pathways of NHC‐boryl radicals enabled by photoredox catalysis. NHC‐boryl radicals are generated via a single‐electron oxidation and subsequently undergo cross‐coupling with the in‐situ‐generated radical anions to yield gem‐difluoroallylboronates. A photoredox‐catalyzed radical arylboration reaction of alkenes was achieved using cyanoarenes as arylating components from which elaborated organoborons were accessed. Mechanistic studies verified the oxidative formation of NHC‐boryl radicals through a single‐electron‐transfer pathway.
NHC‐boryl radicals are generated by single‐electron oxidation of NHC‐BH3 complexes using a photoredox catalytic system. New reaction modes of NHC‐boryl radicals were determined for the facile synthesis of highly elaborated organoboron molecules. Key: N‐heterocyclic carbene (NHC), leaving group (LG).
•Chinese college students reported extremely high prevalence of psychological distress.•Females reported significantly higher prevalence of psychological distress than did males.•Gender moderated the ...effects of resilience and perceived social support on psychological distress.•Male college students relied on both resilience and perceived social support, especially the former, to fight against psychological distress, and females relied mainly on perceived social support to reduce psychological distress.
This study aimed to examine the gender differences in the prevalence of psychological distress, and in the effects of resilience and perceived social support on psychological distress among Chinese college students. A cross-sectional survey was conducted in current study. The psychological distress, resilience, and perceived social support of 1400 university students of China were measured using the Kessler Psychological Distress Scale, the 10-item Connor–Davidson Resilience Scale, and the 12-item Multidimensional Scale of Perceived Social Support, respectively. Multiple group analyses were conducted using structural equation modeling to examine the moderating role of gender in the effects of resilience and perceived social support on psychological distress. The prevalence of psychological distress was 90.86%. Female college students reported a higher prevalence of psychological distress (94.07%) than males (89.11%). Among male college students, the resilience was more strongly associated with psychological distress than perceived social support (−0.18 vs.−0.16). In contrast, among female college students, resilience was not significantly related, but perceived social support was closely related with psychological distress (0.01 vs. −0.31). In conclusion, Chinese female college students are more vulnerable to psychological distress than males. Gender moderates the relationships among resilience, perceived social support, and psychological distress.
α‐Allenol is a versatile synthon in organic synthesis. The catalytic asymmetric synthesis of α‐allenols from readily available starting materials remains a prominent challenge, especially when ...simultaneous control over axial and central chirality is required. Herein, we describe the Cr‐catalyzed enantioconvergent allenylation of aldehydes with racemic propargyl halides to rapidly access a wide range of chiral α‐allenols with adjacent axial and central chiralities. This method features excellent regio‐, diastereo‐ and enantioselectivity control with broad substrate scope, and provides facile access to all four stereoisomers when allied with a Mitsunobu reaction. Preliminary mechanistic studies support radical‐based reaction pathways. The synthetic utility is demonstrated by the application in late‐stage functionalization and the formal total synthesis of (+)‐varitriol.
A Cr‐catalyzed enantioconvergent allenylation reaction of aldehydes with racemic propargyl halides has been developed. This robust method employs simple and readily accessible materials, exhibits exceptional functional group tolerance and broad substrate scope, and provides facile access to a wide range of valuable optically enriched α‐allenols with two or three continuous chiral centers, including both central and axial chirality.
The development of clustered regularly interspaced short-palindromic repeat (CRISPR)-based biotechnologies has revolutionized the life sciences and introduced new therapeutic modalities with the ...potential to treat a wide range of diseases. Here, we describe CRISPR-based strategies to improve human health, with an emphasis on the delivery of CRISPR therapeutics directly into the human body using adeno-associated virus (AAV) vectors. We also discuss challenges facing broad deployment of CRISPR-based therapeutics and highlight areas where continued discovery and technological development can further advance these revolutionary new treatments.
Wang, Zhang, and Gao discuss the progress, concerns, and challenges currently facing CRISPR-based therapeutics, a field that has inspired renewed but cautious interest in human genome editing.
In this brief, we incorporate the impact of preferential imitation rule into a vaccination game based epidemic spreading model on social networks, where each individual chooses one of its neighbors ...as an imitation reference with a probability proportional to the neighbor's degree. Our results indicate that the vaccination coverage can be remarkably increased if hub nodes are preferentially imitated, leading to the dramatic reduction of the epidemic size. We explain this by suggesting that the vaccination willingness of hub nodes is very high when voluntary vaccination mechanism is assumed, who can attract more individuals to take vaccination if they are preferentially imitated. Moreover, a mean-field theoretical approach is developed to further verify our findings. This brief suggests that the human behavioral response is an important factor for spreading dynamics.
•PAN/GO nanofibers with 5–200 nm pores were fabricated for efficient Cr(VI) removal.•BET specific surface area of the porous nanofibers was 164.2 ± 10.8 m2g−1.•Maximum experimental adsorption ...capacity of Cr(VI) was up to 382.5 ± 6.2 mg/g.•Reusability of the porous nanofibers was at least 20 times cycles.•Simple, low cost, green of one-step electrospinning had great industrial potential.
Development of efficient adsorbent with low cost, simple and green production process, and zero secondary pollution for Cr(VI) removal in industrial applications is a great challenge for modern chemical and materials engineering. Here, we developed a new strategy for preparation of porous polyacrylonitrile (PAN)/graphene oxide (GO) nanofibers by simple one-step electrospinning of PAN/GO solution in N,N-dimethylformamide (DMF)/H2O mixed solvent. The resultant porous PAN/GO nanofibers possessed abundant nanopores (5–200 nm) and thus huge Brunauer-Emmett-Teller (BET) specific surface area (164.2 ± 10.8 m2g−1) and excellent interfacial compatibility. The porous structure maximized the adsorption function of the doped GO nanosheets for Cr(VI) ions, an unprecedented experimental Cr(VI) ions adsorption capacity of 382.5 ± 6.2 mg/g was achieved. And the porous PAN/GO nanofibers also exhibited excellent regeneration, after 20 times adsorption–desorption test, the desorption efficiency of the Cr(VI) ions stably maintained more than 75%. More importantly, compared to the current complex chemical synthesis and material structure design methods of Cr(VI) ions adsorbent, the simple one-step electrospinning fully showed great technical advantages for industrial applications including efficient (100% raw material utilization), green (no any harmful chemical by-products), low cost (only PAN and 1.98 wt% GO). Therefore, we suggested that the porous PAN/GO nanofibers will be a promising candidate in industrial applications as a solid adsorbent for Cr(VI) ions adsorption.
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