Oxy-Alkylation of Allylamines with Unactivated Alkyl Bromides and CO₂ via Visible-Light-Driven Palladium Catalysis

A selective oxy-alkylation of allylamines with unactivated alkyl bromides and CO₂ via visible-light-driven palladium catalysis is reported. The commercially available Pd­(PPh₃)₄ is used as the sole catalyst in this three-component reaction. A variety of tertiary, secondary, and primary alkyl bromides undergo reactions to generate important 2-oxazolidinones in high yields and selectivity. The mild reaction conditions, easy scalability, and facile derivatization of products provide great potential for application in organic synthesis and pharmaceutical chemistry

The Role of Stream Water Carbon Dynamics and Export in the Carbon Balance of a Tropical Seasonal Rainforest, Southwest China

<div><p>A two-year study (2009 ∼ 2010) was carried out to investigate the dynamics of different carbon (C) forms, and the role of stream export in the C balance of a 23.4-ha headwater catchment in a tropical seasonal rainforest at Xishuangbanna (XSBN), southwest China. The seasonal volumetric weighted mean (VWM) concentrations of total inorganic C (TIC) and dissolved inorganic C (DIC) were higher, and particulate inorganic C (PIC) and organic C (POC) were lower, in the dry season than the rainy season, while the VWM concentrations of total organic C (TOC) and dissolved organic C (DOC) were similar between seasons. With increased monthly stream discharge and stream water temperature (SWT), only TIC and DIC concentrations decreased significantly. The most important C form in stream export was DIC, accounting for 51.8% of the total C (TC) export; DOC, POC, and PIC accounted for 21.8%, 14.9%, and 11.5% of the TC export, respectively. Dynamics of C flux were closely related to stream discharge, with the greatest export during the rainy season. C export in the headwater stream was 47.1 kg C ha⁻¹ yr⁻¹, about 2.85% of the annual net ecosystem exchange. This finding indicates that stream export represented a minor contribution to the C balance in this tropical seasonal rainforest.</p> </div

Annual dynamics of ratio of stream carbon export to net ecosystem CO₂ exchange (NEE).

<p>(a) Annual dynamics of NEE <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0056646#pone.0056646-Zhang1" target="_blank">[19]</a> and the sum of NEE and TC exported by headwater stream. (b) Annual dynamics of ratios of annual flux of DIC (DIC: NEE), DOC (DOC: NEE), PIC (PIC: NEE), and POC (POC: NEE) to NEE.</p

Annual dynamics of flux of carbon components in a headwater stream in tropical seasonal rainforest.

<p>(a) Annual dynamics in flux of TIC, DIC, and PIC. (b) Annual dynamics in flux of TOC, DOC, and POC.</p

Study site description in Xishuangbanna tropical seasonal rainforest, Southwest China.

<p>(a) Location of the study area (indicated by the black star). (b)The catchment site description was from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Global Digital Elevation Model (GDEM) that is a product of METI and NASA.</p

Concentration and export of various carbon components in a headwater stream in the tropical seasonal rainforest of Xishuangbanna, Southwest China.

<p>Carbon concentration is the seasonal volumetric weighted mean (VWM) concentration of 2009 and 2010.</p

Annual dynamics of rainfall, runoff depth, and stream water temperature in the seasonal tropical rainforest.

<p>Values are averages for 2009 and 2010.</p

DataSheet_1_Genetic testing of sperm donors at a human sperm bank in China.doc

BackgroundIn China, numerous human sperm banks only perform three-generation family history evaluation to exclude genetic diseases with clinical symptoms; therefore, many inherited risks cannot be detected before donor qualification even when a thorough genetic family history evaluation has been performed. Hence, the risk of recessive disease inheritance persists with the current eligibility guidelines in China regarding the donor selection process.MethodsRetrospective study that reviewed the genetic test analyses and clinical outcomes of young adult men who were qualified sperm donors at the Hunan Province Human Sperm Bank of China from January 1, 2018, to May 1, 2021. We included a total of 3231 qualified sperm donors: all donors underwent primary screening for thalassemia and glucose-6-phosphate dehydrogenase (G6PD) deficiency. Whereafter, 278 of donors underwent genetic testing for specific genes, and 43 donors underwent whole exome sequencing.Results2.4% of 3231 qualified sperm donors might have thalassemia and 1.4% might have G6PD deficiency. Sperm donors with thalassemia and G6PD deficiency would be eliminated. Specific gene testing identified 7 of the 278 donors (2.5%) as carriers of at least one pathogenic or likely pathogenic variant in a gene, including 1.9% of 154 donors (3/154) as carrier variants in α-Like or β-Like globin genes, 17.6% of 17 donors (3/17) as carrier variants in GJB2, 12.5% of 8 donors (1/8) as carrier variants in SMN1. In addition, among the 43 sperm donors carrying the 111 pathogenic/likely pathogenic variants, eight (18.6%) were carriers of pathogenic variants of the GJB2 gene. The frequency, therefore, was approximately 1 in 5.ConclusionsThe data suggest that used blood routine and RDT can make a preliminary screening of sperm donors, and special gene testing should be performed for sperm donors according to the regional incidence of specific genetic diseases. Meanwhile, whole exome sequencing can be used as a supplementary application in sperm donor genetic testing, and aid a successful and healthy pregnancy. However, industry guidelines must be modified to incorporate its use.</p

Phosphorylation of Alkenyl and Aryl C–O Bonds via Photoredox/Nickel Dual Catalysis

A phosphorylation of alkenyl and aryl C–O bonds at room temperature via photoredox/nickel dual catalysis is reported. By starting from easily available and inexpensive sulfonates, a variety of important alkenyl phosphonates and aryl phosphine oxides are generated in moderate to excellent yields. This method features mild reaction conditions, high selectivity, good functional group tolerance, wide substrate scope, and easy scalability

Radical Trifluoromethylative Dearomatization of Indoles and Furans with CO₂

Disclosed herein is a versatile and practical strategy for catalytic radical dearomatization. By means of this strategy, we realized the trifluoromethylative dearomatization of indoles and furans with CO₂ via Cu catalysis. We also demonstrated the dearomatization of indoles with C-3 C–O bond formation to generate spirocyclic indolines. A variety of important CF₃-containing spirocyclic indolines and spiroacetals can be synthesized with atmospheric CO₂ under mild reaction conditions. Moreover, these multicomponent reactions feature high selectivity, good functional group tolerance, broad substrate scope, and easy scalability. Further theoretical investigation indicates that this transformation starts with deprotonation of the amine and CO₂ insertion, after which CF₃· radical addition to the indole followed by intramolecular C–O coupling affords the oxazolidone product