Alkaline fuel cells can permit the adoption of platinum group metal‐free (PGM‐free) catalysts and cheap bipolar plates, thus further lowering the cost. With the exploration of PGM‐free hydrogen ...oxidation reaction (HOR) catalysts, nickel‐based compounds have been considered as the most promising HOR catalysts in alkali. Here we report an interfacial engineering through the formation of nickel‐vanadium oxide (Ni/V2O3) heterostructures to activate Ni for efficient HOR catalysis in alkali. The strong electron transfer from Ni to V2O3 could modulate the electronic structure of Ni sites. The optimal Ni/V2O3 catalyst exhibits a high intrinsic activity of 0.038 mA cm−2 and outstanding stability. Experimental and theoretical studies reveal that Ni/V2O3 interface as the active sites can enable to optimize the hydrogen and hydroxyl bindings, as well as protect metallic Ni from extensive oxidation, thus achieving the notable activity and durability.
An interfacial engineering approach was developed to fabricate a low‐cost Ni/V2O3 heterostructure catalyst, which can efficiently and stably catalyze the hydrogen oxidation reaction (HOR) in alkaline media. Experimental and theoretical studies reveal that the Ni/V2O3 interface sites can optimize the hydrogen and hydroxyl bindings, as well as protect metallic Ni from extensive oxidation, thus achieving the notable HOR performance.
Photodynamic therapy (PDT) typically involves oxygen (O2) consumption and therefore suffers from greatly limited anticancer therapeutic efficacy in tumor hypoxia. Here, it is reported for the first ...time that amine‐terminated, PAMAM dendrimer‐encapsulated gold nanoclusters (AuNCs‐NH2) can produce O2 for PDT via their intrinsic catalase‐like activity. The AuNCs‐NH2 not only show optimum H2O2 consumption via the catalase‐like activity over the physiological pH range (i.e., pH 4.8–7.4), but also extend such activity to acidic conditions. The possible mechanism is deduced from that the enriched tertiary amines of dendrimers are easily protonated in acidic solutions to facilitate the preadsorption of OH on the metal surface, thereby favorably triggering the catalase‐like reaction. By taking advantage of the exciting feature on AuNCs‐NH2, the possibility to supply O2 via the catalase‐like activity of AuNCs‐NH2 for PDT against hypoxia of cancer cells was further studied. This proof‐of‐concept study provides a simple way to combine current O2‐dependent cancer therapy of PDT to overcome cancer cell hypoxia, thus achieving more effective anticancer treatments.
PAMAM dendrimer‐encapsulated gold nanoclusters (AuNCs‐NH2) exhibit their catalase‐like activity over a pH range relevant to biological microenvironments (i.e., pH 4.8–7.4), such that AuNCs‐NH2 can catalyze physiological hydrogen peroxide (H2O2) to produce O2 that self‐supplies for photodynamic therapy against hypoxic cancer cells.
To determine the dynamic changes of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA in respiratory and fecal specimens in children with coronavirus disease 2019 (COVID-19).
From ...January 17, 2020 to February 23, 2020, three paediatric cases of COVID-19 were reported in Qingdao, Shandong Province, China. Epidemiological, clinical, laboratory, and radiological characteristics and treatment data were collected. Patients were followed up to March 10, 2020, and dynamic profiles of nucleic acid testing results in throat swabs and fecal specimens were closely monitored.
Clearance of SARS-CoV-2 in respiratory tract occurred within two weeks after abatement of fever, whereas viral RNA remained detectable in stools of pediatric patients for longer than 4 weeks. Two children had fecal SARS-CoV-2 undetectable 20 days after throat swabs showing negative, while that of another child lagged behind for 8 days.
SARS-CoV-2 may exist in children's gastrointestinal tract for a longer time than respiratory system. Persistent shedding of SARS-CoV-2 in stools of infected children raises the possibility that the virus might be transmitted through contaminated fomites. Massive efforts should be made at all levels to prevent spreading of the infection among children after reopening of kindergartens and schools.
A pair of enantiomeric photoswitchable PdII catalysts, alkyne‐PdII/LR−azo and alkyne‐PdII/LS−azo, were prepared via the coordination of alkyne‐PdII and azobenzene‐modified phosphine ligands LR−azo ...and LS−azo. Owing to the cis‐trans photoisomerization of the azobenzene moiety, alkyne‐PdII/LR−azo and alkyne‐PdII/LS−azo exhibited different polymerization activities, helix‐sense selectivities, and enantioselectivities during the polymerization of isocyanide monomers under irradiation of different wavelength lights. Furthermore, the achiral isocyanide monomer A‐1 could be polymerized efficiently using alkyne‐PdII/LR−azo under dark condition in a living/controlled manner. Further, it generated single right‐handed helical poly‐A‐1m(LR−azo), confirmed by the circular dichroism spectra and atomic force microscopy images. However, the polymerization of A‐1 almost could not be initiated under 420 nm light in identical conditions of dark condition. Moreover, the photoswitchable catalyst alkyne‐PdII/LR−azo exhibited high enantioselectivity for the polymerization of the racemates of L‐1 and D‐1, respectively. D‐1 was polymerized preferentially under dark condition with a D‐1/L‐1 rate ratio of 70, yielding single right‐handed polyisocyanides. Additionally, reversible enantioselectivity was observed under 420 nm light using alkyne‐PdII/LR−azo, and the calculated polymerization rate ratio of L‐1/D‐1 was 57 because of the isomerization of the azobenzene moiety of the catalyst. Furthermore, alkyne‐PdII/LS−azo showed opposite enantioselectivity and helix‐sense selectivity during the polymerization of the racemates of L‐1 and D‐1.
Two enantiomeric PdII/LR−azo and PdII/LS−azo could be used as reversible photo‐switchable catalysts for living/controlled polymerization of isocyanide monomers. High enantioselectivity and helix‐sense polymerization could be observed during the polymerization process.
Metal halide perovskites are ideal candidates for indoor photovoltaics (IPVs) because of their easy‐to‐adjust bandgaps, which can be designed to cover the spectrum of any artificial light source. ...However, the serious non‐radiative carrier recombination under low light illumination restrains the application of perovskite‐based IPVs (PIPVs). Herein, polar molecules of amino naphthalene sulfonates are employed to functionalize the TiO2 substrate, anchoring the CsPbI3 perovskite crystal grains with a strong ion–dipole interaction between the molecule‐level polar interlayer and the ionic perovskite film. The resulting high‐quality CsPbI3 films with the merit of defect‐immunity and large shunt resistance under low light conditions enable the corresponding PIPVs with an indoor power conversion efficiency of up to 41.2% (Pin: 334.11 µW cm−2, Pout: 137.66 µW cm−2) under illumination from a commonly used indoor light‐emitting diode light source (2956 K, 1062 lux). Furthermore, the device also achieves efficiencies of 29.45% (Pout: 9.80 µW cm−2) and 32.54% (Pout: 54.34 µW cm−2) at 106 (Pin: 33.84 µW cm−2) and 522 lux (Pin: 168.21 µW cm−2), respectively.
The amino naphthalene sulfonates (ANS) molecules are incorporated as a dipolar interlayer at the buried interface to fabricate CsPbI3 perovskite indoor photovoltaics (PIPVs). The strong ion–dipole interaction between polar ANS molecules and ionic perovskites enables the target PIPVs to deliver a record indoor PCE of up to 41.2% (Pout:137.66 µW cm−2) under a standard LED light source (2956 K, 1062 lux).
Fibrillar centers (FCs) and dense fibrillar components (DFCs) are essential morphologically distinct sub-regions of mammalian cell nucleoli for rDNA transcription and pre-rRNA processing. Here, we ...report that a human nucleolus consists of several dozen FC/DFC units, each containing 2–3 transcriptionally active rDNAs at the FC/DFC border. Pre-rRNA processing factors, such as fibrillarin (FBL), form 18–24 clusters that further assemble into the DFC surrounding the FC. Mechanistically, the 5′ end of nascent 47S pre-rRNA binds co-transcriptionally to the RNA-binding domain of FBL. FBL diffuses to the DFC, where local self-association via its glycine- and arginine-rich (GAR) domain forms phase-separated clusters to immobilize FBL-interacting pre-rRNA, thus promoting directional traffic of nascent pre-rRNA while facilitating pre-rRNA processing and DFC formation. These results unveil FC/DFC ultrastructures in nucleoli and suggest a conceptual framework for considering nascent RNA sorting using multivalent interactions of their binding proteins.
Display omitted
•Visualizing the ultrastructure of FC/DFC and rDNA arrangements in human nucleoli•Processing factors, such as FBL, form protein clusters and then assemble into a DFC•Self-association of GAR in FBL ensures sorting and processing of nascent 47S pre-rRNA•Nascent pre-rRNA sorting via a phase-separation mechanism promotes DFC assembly
Yao et al. unveil the FC/DFC ultrastructure and rDNA arrangements in human nucleoli and show that a phase-separation mechanism promotes nascent pre-rRNA sorting and processing and the assembly of the DFC sub-nucleolar region.
An emerging hallmark of cancer is reprogrammed cellular metabolism, and several cancers involve increased glucose intake and glutamine addiction. Hepatocellular carcinoma (HCC) is one of the most ...fatal cancers, and its molecular basis needs to be delineated to identify biomarkers for its potential treatment without resection. Therefore, this study aimed to determine the metabolism status of HCC by evaluating the expression of the glucose transporter GLUT1 and glutamine transporter ASCT2. We enrolled 192 patients with surgically resected HCC in this study. Their tissue samples were subjected to immunohistochemistry to detect GLUT1 and ASCT2 expression. The prognostic value of GLUT1 and ASCT2 expression and their combined metabolic index was determined by Kaplan-Meier analysis and the Cox proportional hazards model. We found that GLUT1 and ASCT2 expression was significantly upregulated in tumor tissues as compared to adjacent non-tumor tissues and was positively associated with tumor size. Survival analysis revealed that patients with high GLUT1 or ASCT2 expression had poor overall survival (OS) and recurrence-free survival (RFS). In HCC patients, ASCT2 expression was an independent negative prognostic factor for OS (hazard ratio HR, 1.760; 95% confidence interval CI = 1.124-2.755; p = 0.013) and the metabolic index was an independent negative prognostic factor for OS (HR = 1.672, 95% CI = 1.275-2.193, p < 0.001) and RFS (HR = 1.362, 95% CI = 1.066-1.740, p = 0.013). In conclusion, the tumor metabolism status determined by expression of GLUT1 and ASCT2 and their metabolic index is a promising prognostic predictor for HCC patients.
Renal cell carcinoma (RCC) is a common kidney cancer worldwide. Even though current treatments show promising therapeutic effectiveness, metastatic RCC still has limited therapeutic options so that ...novel treatments were urgently needed. Here, we identified that MUC12 was overexpressed in RCC patients and served as poor prognostic factor for RCC progression. Overexpression of MUC12 increased RCC cell growth and cell invasion while deficiency of MUC12 exerted opposite effects on RCC cells. Mechanistic dissection demonstrated that MUC12‐mediated RCC cell growth and cell invasion were dependent of TGF‐β1 signalling because they could be blocked in the presence of TGF‐β1 inhibitor. Moreover, the regulation of TGF‐β1 by MUC12 relied on the transactivation of c‐Jun. MUC12 promoted the recruitment of c‐Jun on the promoter of TGF‐β1, leading to its transcription. Importantly, knockdown of c‐Jun also attenuated MUC12‐mediated TGF‐β1 induction and RCC cell invasion. In summary, our study defines the role of MUC12 in RCC progression and provides rational to develop novel targeted therapy to battle against RCC.
PDF
