Cu1-Fe Dual Sites for Superior Neutral Ammonia Electrosynthesis from Nitrate.

The electrochemical nitrate reduction reaction (NO3RR) is able to convert nitrate (NO3 -) into reusable ammonia (NH3), offering a green treatment and resource utilization strategy of nitrate wastewater and ammonia synthesis. The conversion of NO3 - to NH3 undergoes water dissociation to generate active hydrogen atoms and nitrogen-containing intermediates hydrogenation tandemly. The two relay processes compete for the same active sites, especially under pH-neutral condition, resulting in the suboptimal efficiency and selectivity in the electrosynthesis of NH3 from NO3 -. Herein, we constructed a Cu1-Fe dual-site catalyst by anchoring Cu single atoms on amorphous iron oxide shell of nanoscale zero-valent iron (nZVI) for the electrochemical NO3RR, achieving an impressive NO3 - removal efficiency of 94.8 % and NH3 selectivity of 99.2 % under neutral pH and nitrate concentration of 50 mg L-1 NO3 --N conditions, greatly surpassing the performance of nZVI counterpart. This superior performance can be attributed to the synergistic effect of enhanced NO3 - adsorption on Fe sites and strengthened water activation on single-atom Cu sites, decreasing the energy barrier for the rate-determining step of *NO-to-*NOH. This work develops a novel strategy of fabricating dual-site catalysts to enhance the electrosynthesis of NH3 from NO3 -, and presents an environmentally sustainable approach for neutral nitrate wastewater treatment.

Oxalate-Promoted SO2 Uptake and Oxidation on Iron Minerals: Implications for Secondary Sulfate Aerosol Formation.

Mineral dust serves as a significant source of sulfate aerosols by mediating heterogeneous sulfur dioxide (SO2) oxidation in the atmosphere. Given that a considerable proportion of small organic acids are deposited onto mineral dust via long-range transportation, understanding their impact on atmospheric SO2 transformation and sulfate formation is of great importance. This study investigates the effect of oxalate on heterogeneous SO2 uptake and oxidation phenomenon by in situ FTIR, theoretical calculation, and continuous stream experiments, exploiting hematite (Fe2O3) as an environmental indicator. The results highlight the critical role of naturally deposited oxalate in mononuclear monodentate coordinating surface Fe atoms of Fe2O3 that enhances the activation of O2 for oxidizing SO2 into sulfate. Meanwhile, oxalate increases the hygroscopicity of Fe2O3, facilitating H2O dissociation into reactive hydroxyl groups and further augmenting the SO2 uptake capacity of Fe2O3. More importantly, other conventional iron minerals, such as goethite and magnetite, as well as authentic iron-containing mineral dust, exhibit similar oxalate-promoted sulfate accumulation behaviors. Our findings suggest that oxalate-assisted SO2 oxidation on iron minerals is one of the important contributors to secondary sulfate aerosols, especially during the nighttime with high relative humidity.

Visible Light-Driven Conversion of Carbon-Sequestrated Seawater into Stoichiometric CO and HClO with Nitrogen-Doped BiOCl Atomic Layers.

Seawater is one of the most important CO2 sequestration media for delivering value-added chemicals/fuels and active chlorine; however, this scenario is plagued by sluggish reaction rates and poor product selectivity. Herein, we first report the synthesis of nitrogen-doped BiOCl atomic layers to directly split carbon-sequestrated natural seawater (Yellow Sea, China) into stoichiometric CO (92.8 µmol h-1 ) and HClO (83.2 µmol h-1 ) under visible light with selectivities greater than 90 %. Photoelectrons enriched on the exposed BiOCl{001} facet kinetically facilitate CO2 -to-CO reduction via surface-doped nitrogen bearing Lewis basicity. Photoholes, mainly located on the lateral facets of van der Waals gaps, promote the selective oxidation of Cl- into HClO. Sequestrated CO2 also maintains the pH of seawater at around 4.2 to prevent the alkaline earth cations from precipitating. The produced HClO can effectively kill typical bacteria in the ballast water of ocean-going cargo ships, offering a green and safe way for onsite sterilization.

Surface Boronizing Can Weaken the Excitonic Effects of BiOBr Nanosheets for Efficient O2 Activation and Selective NO Oxidation under Visible Light Irradiation.

The photocatalytic O2 activation for pollutant removal highly depends on the controlled generation of desired reactive oxygen species (ROS). Herein, we demonstrate that the robust excitonic effect of BiOBr nanosheets, which is prototypical for singlet oxygen (1O2) production to partially oxidize NO into a more toxic intermediate NO2, can be weakened by surface boronizing via inducing a staggered band alignment from the surface to the bulk and simultaneously generating more surface oxygen vacancy (VO). The staggered band alignment destabilizes excitons and facilitates their dissociation into charge carriers, while surface VO traps electrons and efficiently activates O2 into a superoxide radical (•O2-) via a one-electron-transfer pathway. Different from 1O2, •O2- enables the complete oxidation of NO into nitrate with high selectivity that is more desirable for safe indoor NO remediation under visible light irradiation. This study provides a facile excitonic effect manipulating method for layered two-dimensional photocatalysts and sheds light on the importance of managing ROS production for efficient pollutant removal.

Reactions of an Isolable Dialkylsilylene with Aroyl Chlorides. A New Route to Aroylsilanes.

The reactions of isolable dialkylsilylene 1 with aromatic acyl chlorides afforded aroylsilanes 3a-3c exclusively. Aroylsilanes 3a-3c were characterized by ¹H-, 13C-, and 29Si-NMR spectroscopy, high-resolution mass spectrometry (HRMS), and single-crystal molecular structure analysis. The reaction mechanisms are discussed in comparison with related reaction of 1 with chloroalkanes and chlorosilanes.

Locally Asymmetric BiOBr for Efficient Exciton Dissociation and Selective O2 Activation toward Oxidative Coupling of Amines.

Two-dimensional (2D) layered photocatalysts with highly ordered out-of-plane symmetry usually display robust excitonic effects, thus being ineffective in driving catalytic reactions that necessitate unchained charge carriers. Herein, taking 2D BiOBr as a prototype model, we implement a superficial asymmetric [Br-Bi-O-Bi] stacking in the out-of-plane direction by selectively stripping off the top-layer Br of BiOBr. This local asymmetry disrupts the diagnostic confinement configuration of BiOBr to urge energetic exciton dissociation into charge carriers and further contributes to the emergence of a surface dipole field that powers the subsequent separation of transient electron-hole pairs. Distinct from the symmetric BiOBr, which activates O2 into 1O2 via an exciton-mediated energy transfer, surface asymmetric BiOBr favors selective O2 activation into ·O2- for a broad range of amine-to-imine conversions. Our work here not only presents a paradigm for asymmetric photocatalyst design but also expands the toolkit available for regulating exciton behaviors in semiconductor photocatalytic systems.

Adult progenitor rejuvenation with embryonic factors.

During ageing, adult stem cells' regenerative properties decline, as they undergo replicative senescence and lose both their proliferative and differentiation capacities. In contrast, embryonic and foetal progenitors typically possess heightened proliferative capacities and manifest a more robust regenerative response upon injury and transplantation, despite undergoing many rounds of mitosis. How embryonic and foetal progenitors delay senescence and maintain their proliferative and differentiation capacities after numerous rounds of mitosis, remains unknown. It is also unclear if defined embryonic factors can rejuvenate adult progenitors to confer extended proliferative and differentiation capacities, without reprogramming their lineage-specific fates or inducing oncogenic transformation. Here, we report that a minimal combination of LIN28A, TERT, and sh-p53 (LTS), all of which are tightly regulated and play important roles during embryonic development, can delay senescence in adult muscle progenitors. LTS muscle progenitors showed an extended proliferative capacity, maintained a normal karyotype, underwent myogenesis normally, and did not manifest tumorigenesis nor aberrations in lineage differentiation, even in late passages. LTS treatment promoted self-renewal and rescued the pro-senescence phenotype of aged cachexia patients' muscle progenitors, and promoted their engraftment for skeletal muscle regeneration in vivo. When we examined the mechanistic basis for LIN28A's role in the LTS minimum combo, let-7 microRNA suppression could not fully explain how LIN28A promoted muscle progenitor self-renewal. Instead, LIN28A was promoting the translation of oxidative phosphorylation mRNAs in adult muscle progenitors to optimize mitochondrial reactive oxygen species (mtROS) and mitohormetic signalling. Optimized mtROS induced a variety of mitohormetic stress responses, including the hypoxic response for metabolic damage, the unfolded protein response for protein damage, and the p53 response for DNA damage. Perturbation of mtROS levels specifically abrogated the LIN28A-driven hypoxic response in Hypoxia Inducible Factor-1α (HIF1α) and glycolysis, and thus LTS progenitor self-renewal, without affecting normal or TS progenitors. Our findings connect embryonically regulated factors to mitohormesis and progenitor rejuvenation, with implications for ageing-related muscle degeneration.

Lin28a maintains a subset of adult muscle stem cells in an embryonic-like state.

During homeostasis and after injury, adult muscle stem cells (MuSCs) activate to mediate muscle regeneration. However, much remains unclear regarding the heterogeneous capacity of MuSCs for self-renewal and regeneration. Here, we show that Lin28a is expressed in embryonic limb bud muscle progenitors, and that a rare reserve subset of Lin28a+Pax7- skeletal MuSCs can respond to injury at adult stage by replenishing the Pax7+ MuSC pool to drive muscle regeneration. Compared with adult Pax7+ MuSCs, Lin28a+ MuSCs displayed enhanced myogenic potency in vitro and in vivo upon transplantation. The epigenome of adult Lin28a+ MuSCs showed resemblance to embryonic muscle progenitors. In addition, RNA-sequencing revealed that Lin28a+ MuSCs co-expressed higher levels of certain embryonic limb bud transcription factors, telomerase components and the p53 inhibitor Mdm4, and lower levels of myogenic differentiation markers compared to adult Pax7+ MuSCs, resulting in enhanced self-renewal and stress-response signatures. Functionally, conditional ablation and induction of Lin28a+ MuSCs in adult mice revealed that these cells are necessary and sufficient for efficient muscle regeneration. Together, our findings connect the embryonic factor Lin28a to adult stem cell self-renewal and juvenile regeneration.

Rice OsUBR7 modulates plant height by regulating histone H2B monoubiquitination and cell proliferation.

Plant height is an important agronomic trait for lodging resistance and yield. Here, we report a new plant-height-related gene, OsUBR7 in rice (Oryza sativa L.); knockout of OsUBR7 caused fewer cells in internodes, resulting in a semi-dwarf phenotype. OsUBR7 encodes a putative E3 ligase containing a plant homeodomain finger and a ubiquitin protein ligase E3 component N-recognin 7 (UBR7) domain. OsUBR7 interacts with histones and monoubiquitinates H2B (H2Bub1) at lysine148 in coordination with the E2 conjugase OsUBC18. OsUBR7 mediates H2Bub1 at a number of chromatin loci for the normal expression of target genes, including cell-cycle-related and pleiotropic genes, consistent with the observation that cell-cycle progression was suppressed in the osubr7 mutant owing to reductions in H2Bub1 and expression levels at these loci. The genetic divergence of OsUBR7 alleles among japonica and indica cultivars affects their transcriptional activity, and these alleles may have undergone selection during rice domestication. Overall, our results reveal a novel mechanism that mediates H2Bub1 in plants, and UBR7 orthologs could be utilized as an untapped epigenetic resource for crop improvement.

LINC01541 overexpression attenuates the 17ß-Estradiol-induced migration and invasion capabilities of endometrial stromal cells.

Endometriosis affects 6-10% of healthy women of reproductive age. Therefore, it is important to study the molecular mechanism by which endometriosis develops. This study examined whether aberrant expression of LINC01541 contributes to the pathogenesis of endometriosis. Human endometrial stromal cells (ESCs) were stimulated with 10 nmol/L of 17ß-Estradiol (17ß-E2) to simulate ectopic cells found in endometriosis. Next, the levels of proteins related to the epithelial-mesenchymal transition (EMT), cell invasion, and metastasis were investigated. The effects of LINCO1541 silencing and overexpression were also examined in ESCs. Cell proliferation and apoptosis were detected by cell counting kit-8 and flow cytometry assays, respectively. ESCs stimulated with 17ß-E2 displayed increased levels of N-Cadherin and vimentin expression, but decreased levels of E-Cadherin expression. 17ß-E2 promoted the migration and invasion of ESCs, and those affects were partially reversed by overexpression of LINC01541. Furthermore, silencing of LINC01541 attenuated apoptosis and promoted the EMT of ESCs, while overexpression of LINC01541 stimulated cell apoptosis, increased the levels of caspase 3 protein, and decreased the levels of B cell leukemia/lymphoma 2 protein. Overexpression of LINC01541 also decreased the expression of vascular endothelial growth factor A (VEGFA) by repressing the Wnt/ß-catenin pathway. Our, results suggest that LINC01541 can inhibit the EMT process, metastasis of ESCs, and VEGFA expression by regulating the Wnt/ß-catenin pathway, which may play an important role in the pathogenesis of endometriosis. Abbreviations: ESCs: endometrial stromal cells; 17ß-E2: 17ß-Estradiol; EMT: epithelial-mesenchymal transition; CASP3: caspase 3; BCL2: B cell leukemia/lymphoma 2; VEGFA: vascular endothelial growth factor A; lncRNA: long non-coding RNA; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; RT-qPCR: reverse transcription-quantitative polymerase chain reaction.

Dihydrogen Splitting Using Dialkylsilylene-Based Frustrated Lewis Pairs.

Isolable dialkylsilylene 5 reacts with dihydrogen in the presence of a small amount of a conventional Lewis acid (BPh3 , BEt3 ) or a base (PPh3 , PEt3 , NPh3 , NEt3 ) at low temperatures in a hydrocarbon solvent, giving the corresponding dihydrosilane 10 in high yields. Both 5/Lewis acid and Lewis base/5 pairs work as a frustrated Lewis pair (FLP) to split dihydrogen, being in accord with the amphoteric nature of silylene 5.

Genomic structural variation-mediated allelic suppression causes hybrid male sterility in rice.

Hybrids between divergent populations commonly show hybrid sterility; this reproductive barrier hinders hybrid breeding of the japonica and indica rice (Oryza sativa L.) subspecies. Here we show that structural changes and copy number variation at the Sc locus confer japonica-indica hybrid male sterility. The japonica allele, Sc-j, contains a pollen-essential gene encoding a DUF1618-domain protein; the indica allele, Sc-i, contains two or three tandem-duplicated ~ 28-kb segments, each carrying an Sc-j-homolog with a distinct promoter. In Sc-j/Sc-i hybrids, the high-expression of Sc-i in sporophytic cells causes suppression of Sc-j expression in pollen and selective abortion of Sc-j-pollen, leading to transmission ratio distortion. Knocking out one or two of the three Sc-i copies by CRISPR/Cas9 rescues Sc-j expression and male fertility. Our results reveal the gene dosage-dependent allelic suppression as a mechanism of hybrid incompatibility, and provide an effective approach to overcome the reproductive barrier for hybrid breeding.

Clinicopathological and Prognostic Significance of CD133 in Glioma Patients: A Meta-Analysis.

In recent years, CD133 has been identified as a cancer stem cell (CSC) marker in gliomas. Nevertheless, the clinical and prognostic value of CD133 in glioma patients remains controversial. Therefore, we conducted a systematic meta-analysis to evaluate the correlation of CD133 with World Health Organization (WHO) grade, age, gender, overall survival (OS), and progression-free survival (PFS) in glioma patients. Eligible studies on this subject were included, and then pooled odd ratios (ORs) and hazard ratios (HRs) with 95 % confidence intervals (95 % CIs) were estimated. Publication bias was assessed by the funnel plots, and heterogeneity and sensitivity were analyzed as well. In the present study, 21 articles with the total number of 1535 patients were included. High expression of CD133 in glioma patients was associated with high WHO grade (III + IV) (n = 11, OR 5.10, 95 % CI 2.99-8.69; p = 0.000), rather than age (n = 4, OR 2.54, 95 % CI 0.68-9.52; p = 0.167) and gender (n = 4, OR 0.71, 95 % CI 0.21-2.45; p = 0.587). In addition, survival analysis demonstrated a significant association between CD133 high expression and poor 2-year OS (n = 11, HR 2.18, 95 % CI 1.29-3.7; p = 0.004), 5-year OS (n = 4, HR 10.39, 95 % CI 2.59-41.63; p = 0.001), as well as PFS (n = 10, HR 2.34, 95 % CI 1.62-3.37; p = 0.000). Taken together, this study suggests that CD133 expression correlates to higher grade of gliomas and worse prognosis in glioma patients. Thus, CD133 could be recommended as a useful pathological and prognostic biomarker in clinical practice.

Reactions of an isolable dialkylsilylene with aromatic nitriles providing a new type of heterosilole.

The 1 : 2 reactions of isolable dialkylsilylene with nitriles having electron-donating aromatic substituents gave 1,4-diaza-2-siloles with a hitherto-unknown type of ring system, in contrast to the previous studies showing exclusive formation of the corresponding 1,3-diaza-2-siloles; the reactions of with aromatic nitriles bearing electron-withdrawing substituents afforded the latter ring system. The remarkable diversity of the reactions is explained by invoking the corresponding nitrile silaylides as key intermediates whose polarity switches depending on the substituents of nitriles.