Defect engineering of high-loading single-atom catalysts for electrochemical carbon dioxide reduction

Electrochemical carbon dioxide reduction reaction (CO2RR) provides an attractive approach to carbon capture and utilization for the production high-value-added products. However, CO2RR still suffers from poor selectivity and low current density due to its sluggish kinetics and multitudinous reaction pathways. Single-atom catalysts (SACs) demonstrate outstanding activity, excellent selectivity, and remarkable atom utilization efficiency, which give impetus to the search for electrocatalytic processes aiming at high selectivity. There appears significant activity in the development of efficient SACs for CO2RR, while the density of the atomic sites remains a considerable barrier to be overcome. To construct high-metal-loading SACs, aggregation must be prevented, and thus novel strategies are required. The key to creating high-density atomically dispersed sites is designing enough anchoring sites, normally defects, to stabilize the highly mobile separated metal atoms. In this review, we summarized the advances in developing high-loading SACs through defect engineering, with a focus on the synthesis strategies to achieve high atomic site loading. Finally, the future opportunities and challenges for CO2RR in the area of high-loading single-atom electrocatalysts are also discussed

Preliminary determination of calcium, phosphorus, and the calcium/phosphorus ratio in cortical bone of Chinstrap penguin using synchrotron X-ray fluorescence analysis

Synchrotron radiation X-ray fluorescence (SR-XRF) approach was applied to analyzing of Chinstrap penguin (Pygoscelis Antarctica) cortical bone. The method enabled the in situ determination of Ca and P concentrations and the Ca/P ratio in cortical bone. The preliminary results show that (1) there is the bone site-related difference for Ca and P concentrations. The mean values for the investigated parameters (on a dry-weight basis) are 30.7% (Ca) and 14.9% (P) for the femoral cortical bone, 21.4% (Ca) and 11.5% (P) for wing cortical bone. (2) The variation for the Ca/P ratio in cortical bone is lower than those for Ca/P ratio in cortical bone is lower than those for Ca and P separately. This is in agreement with the previous report that the specificity of the Ca/P ratio is better than that of Ca and P concentrations and is more reliable for the diagnosis of bone disorders. The authors suggest that further studies be conducted to establish normal values of Ca, P and Ca/P ratio for polar animals and provide a basis for the diagnosis of bone disorders

The Spouses of Stroke Patients Have a Similar Oral Microbiome to Their Partners with an Elevated Risk of Stroke

Spousal members who share no genetic relatedness show similar oral microbiomes. Whether a shared microbiome increases the risk of cerebrovascular disease is challenging to investigate. The aim of this study was to compare the oral microbiota composition of poststroke patients, their partners, and controls and to compare the risk of stroke between partners of poststroke patients and controls. Forty-seven pairs of spouses and 34 control subjects were recruited for the study. Alcohol use, smoking, metabolic disease history, clinical test results, and oral health were documented. Oral microbiome samples were measured by 16S rRNA gene sequencing. The risk of stroke was measured by risk factor assessment (RFA) and the Framingham Stroke Profile (FSP). Poststroke patients and their partners exhibited higher alpha diversity than controls. Principal-coordinate analysis (PCoA) showed that poststroke patients share a more similar microbiota composition with their partners than controls. The differentially abundant microbial taxa among the 3 groups were identified by linear discriminant analysis effect size (LEfSe) analysis. The risk factor assessment indicated that partners of poststroke patients had a higher risk of stroke than controls. Spearman correlation analysis showed that Prevotellaceae was negatively associated with RFA. Lactobacillales was negatively associated with FSP, while Campilobacterota and [Eubacterium]_nodatum_group were positively associated with FSP. These results suggest that stroke risk may be transmissible between spouses through the oral microbiome, in which several bacteria might be involved in the pathogenesis of stroke

Association between oral microbial dysbiosis and poor functional outcomes in stroke-associated pneumonia patients

Abstract Background Despite advances in our understanding of the critical role of the microbiota in stroke patients, the oral microbiome has rarely been reported to be associated with stroke-associated pneumonia (SAP). We sought to profile the oral microbial composition of SAP patients and to determine whether microbiome temporal instability and special taxa are associated with pneumonia progression and functional outcomes. Methods This is a prospective, observational, single-center cohort study that examined patients with acute ischemic stroke (AIS) who were admitted within 24 h of experiencing a stroke event. The patients were divided into three groups based on the occurrence of pneumonia and the use of mechanical ventilation: nonpneumonia group, SAP group, and ventilator-associated pneumonia (VAP) group. We collected oral swabs at different time points post-admission and analyzed the microbiota using 16 S rRNA high-throughput sequencing. The microbiota was then compared among the three groups. Results In total, 104 nonpneumonia, 50 SAP and 10 VAP patients were included in the analysis. We found that SAP and VAP patients exhibited significant dynamic differences in the diversity and composition of the oral microbiota and that the magnitude of this dysbiosis and instability increased during hospitalization. Then, by controlling the potential effect of all latent confounding variables, we assessed the changes associated with pneumonia after stroke and explored patients with a lower abundance of Streptococcus were more likely to suffer from SAP. The logistic regression analysis revealed that an increase in specific taxa in the phylum Actinobacteriota was linked to a higher risk of poor outcomes. A model for SAP patients based on oral microbiota could accurately predict 30-day clinical outcomes after stroke onset. Conclusions We concluded that specific oral microbiota signatures could be used to predict illness development and clinical outcomes in SAP patients. We proposed the potential of the oral microbiota as a non-invasive diagnostic biomarker in the clinical management of SAP patients. Clinical Trial registration NCT04688138. Registered 29/12/2020, https://clinicaltrials.gov/ct2/show/NCT04688138

A Two-Coordinate Neutral Germylene Supported by a β‑Diketiminate Ligand in the Radical State

Using the new β-diketimine <b>1a</b> (PhCH­(PhCN-Dip)₂, Dip = 2,6-^<i>i</i>Pr₂C₆H₃), which possesses three phenyl groups at the ligand backbone, we synthesized the β-diketiminato germylene chloride <b>2</b> (LGeCl, L = [PhC­(PhCN-Dip)₂]⁻). The β-diketiminato germanium radical complex <b>3</b> (^•LGe:, ^•L = ^•[PhC­(PhCN-Dip)₂]^2–) has been isolated by reduction of LGeCl with sodium/naphthalene in 64% yield. X-ray diffraction, HR-MS, and electron paramagnetic resonance analyses together with DFT calculations reveal that <b>3</b> exhibits a remarkably different structure in comparison with the reported Ge­(I) radical <b>C</b> (L′^•Ge:, L′ = [HC­(^<i>t</i>BuCN-Dip)₂]⁻). The inductive effect of three phenyl groups leads to the backbone of ligand <b>1</b> being more electron deficient, and therefore the singly occupied molecular orbital (SOMO) of radical <b>3</b> is mainly composed of a π-antibonding orbital between the N and C atoms. This results in ca. 0.14 Å shorter N–Ge bonds and ca. 0.1 Å longer C–N bonds in <b>3</b> in comparison to those observed in <b>C</b>. Thus, the radical <b>3</b> is a two-coordinate germylene stabilized by an N-heterocyclic radical ligand