Theoretical Investigation of Regioselectivity and Stereoselectivity in AIBN/HSnBu₃‑Mediated Radical Cyclization of <i>N</i>‑(2-Iodo-4,6-dimethylphenyl)‑<i>N</i>,2-dimethyl-(2<i>E</i>)‑butenamide

In this study, we employed the density functional method to simulate AIBN/HSnBu₃-mediated radical cyclizations with different axially chiral conformers of <i>N</i>-(2-iodo-4,6-dimethylphenyl)-<i>N</i>,2-dimethyl-(2<i>E</i>)-butenamide as substrates. We constructed a reaction potential energy profile using the Gibbs free energies of the located stationary points. The thermodynamic and kinetic data of the profile were further used to evaluate the regioselectivity, stereoselectivity, and product distribution of the cyclizations. Additionally, we compared the present HSnBu₃-mediated radical cyclization with the experimentally available Heck reaction and found that such a radical cyclization can convert (<i>M</i>,<i>Z</i>) and (<i>P</i>,<i>Z</i>) <i>o</i>-iodoanilide substrates to centrally chiral products with high chirality transfer. The goal of this study was to estimate the practicality of theoretically predicting the memory of chirality in such radical cyclizations. The present results can provide a strategy from a theoretical viewpoint for experimentally synthesizing highly stereoselective carbocyclic and heterocyclic compounds using radical cyclization methods

Transport of carbon nanoparticles in porous media and its effect on the transport of concurrent contaminants

The extensive use of carbon nanoparticles (CNPs) inevitably results in their introduction into soil and groundwater, which poses a significant risk to the safety of these natural resources. Therefore, it is crucial to understand the transport behavior of CNPs in the subsurface environment and how it affects the transport of co-contaminants such as heavy metals, organic compounds, nano-plastics, engineered metal and metal oxide nanoparticles. This review focuses on recent advancements in research on the transport behaviors of CNPs in porous media and its effect on the transport of co-contaminants, with respect to the mechanisms associated with CNPs transport and the mechanisms of action of CNPs on co-contaminant transport, as well as the factors that influence these processes. Results of the existing research indicate that aggregation, attachment, detachment, straining, blocking and ripening are the primary processes governing CNPs transport due to their unique physiochemistry. CNPs can either act as carriers, facilitating the transport of co-contaminants, or as competitors, hindering the deposition of co-contaminants. Additionally, they can serve as collectors for co-contaminant deposition or co-deposit with co-contaminants, inhibiting their transport. The interactions between CNPs, co-contaminants, and the medium determine the exact role played by CNPs in co-contaminant transport. The processes of CNPs transport and its effect on co-contaminant transport are affected by the physicochemical properties of CNPs and porous media, as well as the chemistry and hydrodynamics of groundwater. This review article is of great significance for risk assessment of CNPs in soil and groundwater.</p

Associations between Tumor Necrosis Factor-α Polymorphisms and Risk of Psoriasis: A Meta-Analysis

<div><p>Background</p><p>Tumor necrosis factor-α (TNF-α) may play an important role in the recalcitrant inflammatory and hyperproliferative dermatosis of psoriasis, and there may be a relationship between TNF-α polymorphisms and psoriasis risk. </p> <p>Methods</p><p>We performed a meta-analysis to evaluate the associations between TNF-α polymorphisms and psoriasis. Electronic searches of Pubmed, Embase, and Web of Science were performed for all publications on the associations between TNF-α polymorphisms and psoriasis through September 26, 2012. The pooled odds ratios (ORs) with their 95% confidence interval (95%CIs) were calculated to assess the associations.</p> <p>Results</p><p>Sixteen case-control studies with a total of 2,253 psoriasis cases and 1,947 controls on TNF-α 308 G/A polymorphism and fourteen studies on TNF-α 238 G/A polymorphism with 2,104 cases and 1,838 controls were finally included into the meta-analysis. Overall, TNF-α 308 G/A polymorphism was significantly associated with decreased risk of psoriasis under three genetic comparison models (for A versus G: fixed-effects OR 0.71, 95%CI 0.62-0.82, P < 0.001; for AG versus GG: fixed-effects OR 0.67, 95%CI 0.57-0.78, P < 0.001; for AA/AG versus GG: fixed-effects OR 0.67, 95%CI 0.58-0.78, P < 0.001). In addition, TNF-α 238 G/A polymorphism was associated with increased risk of psoriasis under three genetic models (for A versus G: fixed-effects OR 2.46, 95%CI 2.04-2.96, P < 0.001; for AG versus GG: fixed-effects OR 2.69, 95%CI 2.20-3.28, P < 0.001; for AA/AG versus GG: fixed-effects OR 2.68, 95%CI 2.20-3.26, P < 0.001). Subgroup analysis by ethnicity identified a significant association between TNF-α 308 G/A polymorphism and decreased risk of psoriasis in both Caucasians and Asians and a significant association between TNF-α 238 G/A polymorphism and increased risk of psoriasis in Caucasians.</p> <p>Conclusions</p><p>The meta-analysis suggests that TNF-α 308 G/A polymorphism is associated with decreased risk of psoriasis, while TNF-α 238 G/A is associated with increased risk of psoriasis.</p> </div

Dispersed CuO Nanoparticles on a Silicon Nanowire for Improved Performance of Nonenzymatic H₂O₂ Detection

A finely dispersed CuO nanoparticle electrocatalyst on a silicon nanowire (SiNW) was achieved via a designed, precursor-mediated strategy by combining metal-assisted chemical etching, electroless deposition, and thermal oxidation. The CuO assembled on silicon nanowires (CuO-SiNWs) showed a competent sensitivity of 22.27 μA/mM, a wider linear range from 0.01 to 13.18 mM, and a comparable detection limit of 1.6 μM (3S/N) for nonenzymatic H₂O₂ detection. The archetype sensor also demonstrated eligible selectivity against common interfering species. By the introduction of the SiNW carrier, which led to mitigated conglomeration of the electrocatalyst and a favorable microstructure of the electrocatalyst–carrier system, improved signal-concentration linearity and higher electrocatalyst utilization efficiency were obtained with CuO-SiNWs. These results demonstrated the feasibility of the synthetic strategy and the potential of the nanocomposite as a promising candidate for H₂O₂ sensing

Forest plot in the meta-analysis of TNF-α 238 G/A polymorphism and psoriasis risk under the dominant genetic model (<b>AA</b>/<b>AG</b> versus GG).

<p>Forest plot in the meta-analysis of TNF-α 238 G/A polymorphism and psoriasis risk under the dominant genetic model (<b>AA</b>/<b>AG</b> versus GG).</p

Forest plot in the meta-analysis of TNF-α 308 G/A polymorphism and psoriasis risk under the dominant genetic model (<b>AA</b>/<b>AG</b> versus GG).

<p>Forest plot in the meta-analysis of TNF-α 308 G/A polymorphism and psoriasis risk under the dominant genetic model (<b>AA</b>/<b>AG</b> versus GG).</p

Forest plot in the meta-analysis of TNF-α 238 G/A polymorphism and psoriasis risk under the allele comparison model (A versus G).

<p>Forest plot in the meta-analysis of TNF-α 238 G/A polymorphism and psoriasis risk under the allele comparison model (A versus G).</p

Begg’s funnel plot in the meta-analysis of the association between TNF-α 308 G/A polymorphism and psoriasis risk under the allele comparison model (A versus G).

<p>Begg’s funnel plot in the meta-analysis of the association between TNF-α 308 G/A polymorphism and psoriasis risk under the allele comparison model (A versus G).</p

Begg’s funnel plot in the meta-analysis of the association between TNF-α 238 G/A polymorphism and psoriasis risk under the allele comparison model (A versus G).

<p>Begg’s funnel plot in the meta-analysis of the association between TNF-α 238 G/A polymorphism and psoriasis risk under the allele comparison model (A versus G).</p

Forest plot in the meta-analysis of TNF-α 308 G/A polymorphism and psoriasis risk under the allele comparison model (A versus G).

<p>Forest plot in the meta-analysis of TNF-α 308 G/A polymorphism and psoriasis risk under the allele comparison model (A versus G).</p