Additions of Organomagnesium Halides to α‑Alkoxy Ketones: Revision of the Chelation-Control Model

The chelation-control model explains the high diastereoselectivity obtained in additions of organometallic nucleophiles to α-alkoxy ketones but fails for reactions of allylmagnesium halides. Low diastereoselectivity in ethereal solvents results from no chelation-induced rate acceleration. Additions of allylmagnesium bromide to carbonyl compounds are diastereoselective using CH₂Cl₂ as the solvent even though rate acceleration is still absent. Stereoselectivity likely arises from the predominance of the chelated form in solution. Therefore, a revised chelation-control model is proposed

Additions of Organomagnesium Halides to α‑Alkoxy Ketones: Revision of the Chelation-Control Model

The chelation-control model explains the high diastereoselectivity obtained in additions of organometallic nucleophiles to α-alkoxy ketones but fails for reactions of allylmagnesium halides. Low diastereoselectivity in ethereal solvents results from no chelation-induced rate acceleration. Additions of allylmagnesium bromide to carbonyl compounds are diastereoselective using CH₂Cl₂ as the solvent even though rate acceleration is still absent. Stereoselectivity likely arises from the predominance of the chelated form in solution. Therefore, a revised chelation-control model is proposed

Additions of Organomagnesium Halides to α‑Alkoxy Ketones: Revision of the Chelation-Control Model

The chelation-control model explains the high diastereoselectivity obtained in additions of organometallic nucleophiles to α-alkoxy ketones but fails for reactions of allylmagnesium halides. Low diastereoselectivity in ethereal solvents results from no chelation-induced rate acceleration. Additions of allylmagnesium bromide to carbonyl compounds are diastereoselective using CH₂Cl₂ as the solvent even though rate acceleration is still absent. Stereoselectivity likely arises from the predominance of the chelated form in solution. Therefore, a revised chelation-control model is proposed

Additional file 1 of Panax notoginseng saponins prevent dementia and oxidative stress in brains of SAMP8 mice by enhancing mitophagy

Supplementary Material 1: Supplement figures of western blottin

Visible-Light-Promoted Carbene Insertion and Decarbonylation for the Synthesis of α‑Substituted γ‑Ketoesters

Herein, we report a blue visible-light-promoted approach for preparing a variety of α-substituted γ-ketoester derivatives through carbene insertion and the decarbonylation of enaminones and diazoesters. These reactions use readily available starting materials and transition-metal-free, eco-friendly procedures that are amenable to gram-scale synthesis and wide functional group tolerance. This methodology may be useful for constructing polysubstituted heterocycles with potential biological activity

Nanoplastics Affect the Bioaccumulation and Gut Toxicity of Emerging Perfluoroalkyl Acid Alternatives to Aquatic Insects (<i>Chironomus kiinensis</i>): Importance of Plastic Surface Charge

Persistent organic pollutants (POPs) have been widely suggested as contributors to the aquatic insect biomass decline, and their bioavailability is affected by engineered particles. However, the toxicity effects of emerging ionizable POPs mediated by differentially charged engineered nanoparticles on aquatic insects are unknown. In this study, 6:2 chlorinated polyfluoroalkyl ether sulfonate (F-53B, an emerging perfluoroalkyl acid alternative) was selected as a model emerging ionizable POP; the effect of differentially charged nanoplastics (NPs, 50 nm, 0.5 g/kg) on F-53B bioaccumulation and gut toxicity to Chironomus kiinensis were investigated through histopathology, biochemical index, and gut microbiota analysis. The results showed that when the dissolved concentration of F-53B remained constant, the presence of NPs enhanced the adverse effects on larval growth, emergence, gut oxidative stress and inflammation induced by F-53B, and the enhancement caused by positively charged NP-associated F-53B was stronger than that caused by the negatively charged one. This was mainly because positively charged NPs, due to their greater adsorption capacity and higher bioavailable fraction of associated F-53B, increased the bioaccumulation of F-53B in larvae more significantly than negatively charged NPs. In addition, positively charged NPs interact more easily with gut biomembranes and microbes with a negative charge, further increasing the probability of F-53B interacting with gut biomembranes and microbiota and thereby aggravating gut damage and key microbial dysbacteriosis related to gut health. These findings demonstrate that the surface charge of NPs can regulate the bioaccumulation and toxicity of ionizable POPs to aquatic insects

Additional file 1 of Accelerometer-measured physical activity, sedentary behavior, and risk of incident pelvic organ prolapse: a prospective cohort study in the UK Biobank

Additional file 1: Checklist. Strengthening the Reporting of Observational Studies in Epidemiology (STROBE). Figure S1. Directed acyclic graph to guide covariate selection. Figure S2. Stratified analyses of the association between LPA (per 1 h/day increment) and the risk of POP. Figure S3. Stratified analyses of the association between MPA (per 30 min/day increment) and the risk of POP. Figure S4. Stratified analyses of the association between VPA (per 15 min/day increment) and the risk of POP. Figure S5. Stratified analyses of the association between sedentary behavior (per 1h/day increment) and the risk of POP. Figure S6. Dose-response association of PA and sedentary behavior with the risk of POP after excluding participants who were diagnosed with POP in the first two years of follow-up (N=47,190). Figure S7. Dose-response association between PA and the risk of POP with mutual adjustment (N=47,674). Figure S8. Dose-response association of PA and sedentary behavior with the risk of POP in complete cases (N=46,283). Table S1. Participant characteristics by inclusion status. Table S2. Joint association of LPA and MPA with the risk of POP. Table S3. Joint association of LPA and VPA with the risk of POP. Table S4. Joint association of MPA and VPA with the risk of POP. Table S5. Association of PA and sedentary behavior with the risk of POP after excluding participants who were diagnosed with POP in the first two years of follow-up (N=47,190). Table S6. Association of PA and sedentary behavior with the risk of POP in competing risk models (N=47,674). Table S7. Association between PA and the risk of POP with mutual adjustment (N=47,674). Table S8. Association of PA and sedentary behavior with the risk of POP in complete cases (N=46,283)

Proteomic Analysis of Leaves and Roots of Common Wheat (<i>Triticum aestivum</i> L.) under Copper-Stress Conditions

Proteomic studies were performed to identify the protein species involved in copper (Cu) stress responses in common wheat. Two-week-old wheat seedlings were exposed to 100 μM CuSO₄ treatment for 3 days. Growth of shoots and roots was markedly inhibited and lipid peroxidation was greatly increased. Cu was readily absorbed by wheat seedlings, with greater Cu contents in roots than in leaves. Using 2-DE method, 98 protein spots showed significantly enhanced or reduced abundance, of which 93 were successfully identified. Of these identified protein species, 49 and 44 were found in roots and leaves, respectively. Abundance of most of identified protein species, which function in signal transduction, stress defense, and energy production, was significantly enhanced, while that of many protein species involved in carbohydrate metabolism, protein metabolism, and photosynthesis was severely reduced. The Cu-responsive protein interaction network revealed 36 key proteins, most of which may be regulated by abscisic acid (ABA), ethylene, jasmonic acid (JA), and so on. Exogenous JA application showed a protective effect against Cu stress and significantly increased transcripts of the glutathione S-transferase (<i>GST</i>) gene. This study provides insight into the molecular mechanisms of Cu responses in higher plants

Proteomic Analysis of Leaves and Roots of Common Wheat (<i>Triticum aestivum</i> L.) under Copper-Stress Conditions

Proteomic studies were performed to identify the protein species involved in copper (Cu) stress responses in common wheat. Two-week-old wheat seedlings were exposed to 100 μM CuSO₄ treatment for 3 days. Growth of shoots and roots was markedly inhibited and lipid peroxidation was greatly increased. Cu was readily absorbed by wheat seedlings, with greater Cu contents in roots than in leaves. Using 2-DE method, 98 protein spots showed significantly enhanced or reduced abundance, of which 93 were successfully identified. Of these identified protein species, 49 and 44 were found in roots and leaves, respectively. Abundance of most of identified protein species, which function in signal transduction, stress defense, and energy production, was significantly enhanced, while that of many protein species involved in carbohydrate metabolism, protein metabolism, and photosynthesis was severely reduced. The Cu-responsive protein interaction network revealed 36 key proteins, most of which may be regulated by abscisic acid (ABA), ethylene, jasmonic acid (JA), and so on. Exogenous JA application showed a protective effect against Cu stress and significantly increased transcripts of the glutathione S-transferase (<i>GST</i>) gene. This study provides insight into the molecular mechanisms of Cu responses in higher plants

Agronomic characteristics, industrial traits and the stalks borer damage percentage in transgenic sugarcane lines and the non-transgenic control.

<p>Agronomic characteristics, industrial traits and the stalks borer damage percentage in transgenic sugarcane lines and the non-transgenic control.</p