Abstract
Harnessing visible light to trigger (aza and thia) Paternò‐Büchi reaction injects new vitality into 2+2 photocyclization reaction and enable impressive reactivity modes. The popular (aza and ...thia) Paternò‐Büchi reaction is one of the most efficient ways to synthesize strained four‐membered heterocycles. Recently, visible‐light‐triggered (aza and thia) Paternò‐Büchi reactions have received considerable attentions as this strategy has overcome some long‐standing challenges, and remarkable achievements have been made within this field. Strained four‐membered heterocyclics with favorable properties provide a perfect combination of stable skeletons for pharmaceutical chemistry and reaction intermediates for further transformation. In this review, we highlight the most recent advances in visible‐light‐triggered (aza and thia) Paternò‐Büchi reaction with an emphasis on reaction mechanism and applications. Organization of the review follows a subdivision according to reaction type and substrate classes.
In comparison to severe acute respiratory syndrome coronavirus (SARS-CoV), SARS-CoV-2 appears to be more contagious 1, and coronavirus disease 2019 (COVID-19) patients demonstrate varied clinical ...manifestations distinct from those seen in patients with SARS-CoV and Middle East respiratory syndrome coronavirus infections 2. Collective results from the clinical and epidemiological observations suggest a distinct viral–host interaction in COVID-19 patients. Profiling of the antibody response during SARS-CoV-2 infection may help improve our understanding of the viral–host interaction and the immunopathological mechanisms of the disease.
Humoral immune response to SARS-CoV-2 showed an early response of IgA, instead of IgM, in COVID-19 patients. As highlighted by this study, enhanced IgA responses observed in severe COVID-19 might confer damaging effects in severe COVID-19.
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In the early stage of osteoarthritis (OA), cartilage degradation in the surface region leads to superficial cartilage defect. However, enhancing the regeneration of cartilage defect remains a great ...challenge for existing hydrogel technology because of the weak adhesion to wet tissue. In the present study, an injectable mussel-inspired highly adhesive hydrogel with exosomes was investigated for endogenous cell recruitment and cartilage defect regeneration. The hydrogel with high bonding strength to the wet surface was prepared using a crosslinked network of alginate-dopamine, chondroitin sulfate, and regenerated silk fibroin (AD/CS/RSF). Compared with commercial enbucrilate tissue adhesive, the AD/CS/RSF hydrogel provided a comparative lap shear strength of 120 kPa, with a similar gelation time and a higher capacity for maintaining adhesive strength. The AD/CS/RSF/EXO hydrogel with encapsulated exosomes recruited BMSCs migration and inflation, promoted BMSCs proliferation and differentiation. Most importantly, the AD/CS/RSF/EXO hydrogel accelerated cartilage defect regeneration in situ, and extracellular matrix remodeling after injection in rat patellar grooves. The exosomes released by the hydrogels could recruit BMSCs into the hydrogel and neo-cartilage via the chemokine signaling pathway. Our findings reveal an injectable and adhesive hydrogel for superficial cartilage regeneration, which is a promising approach for minimally treating cartilage defect with arthroscopic assistance.
Abstract
Background
Long-term care facilities (LTCFs) were high-risk settings for COVID-19 outbreaks.
Objective
To assess the impacts of the COVID-19 pandemic on LTCFs, including rates of infection, ...hospitalisation, case fatality, and mortality, and to determine the association between control measures and SARS-CoV-2 infection rates in residents and staff.
Method
We conducted a systematic search of six databases for articles published between December 2019 and 5 November 2021, and performed meta-analyses and subgroup analyses to identify the impact of COVID-19 on LTCFs and the association between control measures and infection rate.
Results
We included 108 studies from 19 countries. These studies included 1,902,044 residents and 255,498 staff from 81,572 LTCFs, among whom 296,024 residents and 36,807 staff were confirmed SARS-CoV-2 positive. The pooled infection rate was 32.63% (95%CI: 30.29 ~ 34.96%) for residents, whereas it was 10.33% (95%CI: 9.46 ~ 11.21%) for staff. In LTCFs that cancelled visits, new patient admissions, communal dining and group activities, and vaccinations, infection rates in residents and staff were lower than the global rate. We reported the residents’ hospitalisation rate to be 29.09% (95%CI: 25.73 ~ 32.46%), with a case-fatality rate of 22.71% (95%CI: 21.31 ~ 24.11%) and mortality rate of 15.81% (95%CI: 14.32 ~ 17.30%). Significant publication biases were observed in the residents’ case-fatality rate and the staff infection rate, but not in the infection, hospitalisation, or mortality rate of residents.
Conclusion
SARS-CoV-2 infection rates would be very high among LTCF residents and staff without appropriate control measures. Cancelling visits, communal dining and group activities, restricting new admissions, and increasing vaccination would significantly reduce the infection rates.
The first visible-light driven aerobic oxidation for the direct selenation of (hetero)arenes has been developed at room temperature, providing an eco-friendly, atom-economical protocol to prepare ...unsymmetrical selenides from easily accessible diselenides. The reaction is scalable and tolerates a wide spectrum of functional groups to deliver products in very high yields.
By integrating three beneficial considerations (alloying effect, surface compositional modulation and supporting aspect), a series of 3-dimensional (3D) rGO-CNT supported activated electrocatalysts ...have been prepared by electrochemical Cu depletion from as-prepared PdAuCu/rGO-CNTs catalysts. The as-prepared and activated catalysts were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS). The results show that, on one hand, the Cu content in PdAuCu/rGO-CNTs greatly affects the electrochemical feature and surface topography of the following activated counterpart; on the other hand, the activated PdAuCu(50%)/rGO-CNTs with typical flower-like topography exhibits excellent electrocatalytic activity as high as 1046.72 and 2347.97mAmg−1 Pd for methanol and ethanol oxidation in alkaline solution, revealing the highest activity improvement compared with the other ones. The catalytic activity enhancement causation based upon the electrochemical activation induced unique structural and functional properties of different component in the nanocatalyst and the synergistic effect between them was also discussed in this article.
Colorectal cancer (CRC) is one of the most common types of malignant tumor. Many genetic factors have been proved to show high association with the occurrence and development of CRC and many ...mutations are detected in CRC. PTPN4/PTP‐MEG1 is a widely expressed non–receptor protein tyrosine phosphatase. Over the past three decades, PTPN4 has been demonstrated in the literature to participate in many biological processes. In this study, we identified a nonsense mutation of PTPN4 with a mutation ratio of 90.90% from 1 case of rectal cancer, leading to loss of function in PTPN4 gene. Several somatic mutations occurred in 5/137 rectal cancer samples from The Cancer Genome Atlas Rectum Adenocarcinoma (TCGA READ) database. Interestingly, we found that PTPN4 negative cytoplasm staining was more prone to lymphatic metastasis (N = 50, P = 0.0153) and low expression of PTPN4 in rectal cancer was highly associated with poor prognosis. Overexpression of PTPN4 suppressed the cell growth, and moreover, the loss of PTPN4 accelerated cell growth and boosted clonogenicity of CRC cells. Furthermore, we revealed that the deletion of PTPN4 promoted the tumor formation of NCM460 cells in vivo. In terms of the molecular mechanism, we demonstrated that PTPN4 dephosphorylates pSTAT3 at the Tyr705 residue with a direct interaction and suppresses the transcriptional activity of STAT3. In summary, our study revealed a novel mechanism that the tumorigenesis of colorectal cancer might be caused by the loss of PTPN4 through activating STAT3, which will broaden the therapy strategy for anti–rectal cancer in the future.
In our study, we identified a nonsense mutation of PTPN4 with mutation ratio of 90.90% from 1 case of rectal cancer. Overexpression of PTPN4 suppressed the growth of colorectal cancer cells. PTPN4 dephosphorylates pSTAT3 at the Tyr705 residue with a direct interaction and depresses the transcriptional activity of STAT3.
We previously observed enhanced immunoglobulin A (IgA) responses in severe COVID‐19, which might confer damaging effects. Given the important role of IgA in immune and inflammatory responses, the aim ...of this study was to investigate the dynamic response of the IgA isotype switch factor TGF‐β1 in COVID‐19 patients. We observed, in a total of 153 COVID‐19 patients, that the serum levels of TGF‐β1 were increased significantly at the early and middle stages of COVID‐19, and correlated with the levels of SARS‐CoV‐2‐specific IgA, as well as with the APACHE II score in patients with severe disease. In view of the genetic association of the TGF‐β1 activator THBS3 with severe COVID‐19 identified by the COVID‐19 Host Genetics Initiative, this study suggests TGF‐β1 may play a key role in COVID‐19.
We developed a new means of activating aldoximes by an
in situ
generated thiocyanate radical from ammonium thiocyanate and molecular oxygen at room temperature. With a catalytic amount of organic dye ...aizenuranine as the photocatalyst, the dehydration of aldoximes proceeds smoothly under visible light irradiation, providing a simple to handle, excellent functional group tolerance, and metal-free protocol for a wide range of nitriles.
This work describes the first example of dehydration of aldoximes by an
in situ
generated radical-based hydrogen abstraction reaction.
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