Transition-Metal-Free α Csp3−H Cyanation of Sulfonamides

This report describes the site-selective α-functionalization of sulfonylamide derivatives through the in-situ generation of imine intermediates. The N−F sulfonylamides, which could facilitate the elimination to generate imines, are coupled with TBACN to efficiently and mildly afford α-amino cyanides. Comparing with Strecker reaction, this transformation offers a complementary strategy to efficiently construct α-amino cyanides from direct α C−H functionalization of sulfonylamindes. The reaction is also characterized by broad substrate scope and flash chromatography column free workup. More importantly, the new two-electron pathway to generate imines through manipulation of the leaving group allows us to achieve excellent α site-selectivity.     

Insights on Ferroptosis and Colorectal Cancer: Progress and Updates

Patients with advanced-stage or treatment-resistant colorectal cancer (CRC) benefit less from traditional therapies; hence, new therapeutic strategies may help improve the treatment response and prognosis of these patients. Ferroptosis is an iron-dependent type of regulated cell death characterized by the accumulation of lipid reactive oxygen species (ROS), distinct from other types of regulated cell death. CRC cells, especially those with drug-resistant properties, are characterized by high iron levels and ROS. This indicates that the induction of ferroptosis in these cells may become a new therapeutic approach for CRC, particularly for eradicating CRC resistant to traditional therapies. Recent studies have demonstrated the mechanisms and pathways that trigger or inhibit ferroptosis in CRC, and many regulatory molecules and pathways have been identified. Here, we review the current research progress on the mechanism of ferroptosis, new molecules that mediate ferroptosis, including coding and non-coding RNA; novel inducers and inhibitors of ferroptosis, which are mainly small-molecule compounds; and newly designed nanoparticles that increase the sensitivity of cells to ferroptosis. Finally, the gene signatures and clusters that have predictive value on CRC are summarized.     

Enhanced Carrier Diffusion Enables Efficient Back-Contact Perovskite Photovoltaics

Back-contact architectures offer a promising route to improve the record efficiencies of perovskite solar cells (PSCs) by eliminating parasitic light absorption. However, the performance of back-contact PSCs is limited by inadequate carrier diffusion in perovskite. Here, we report that perovskite films with a preferred out-of-plane orientation show improved carrier dynamic properties. With the addition of guanidine thiocyanate, the films exhibit carrier lifetimes and mobilities increased by 3–5 times, leading to diffusion lengths exceeding 7 μm. The enhanced carrier diffusion results from substantial suppression of nonradiative recombination and improves charge collection. Devices using such films achieve reproducible efficiencies reaching 11.2 %, among the best performances for back-contact PSCs. Our findings demonstrate the impact of carrier dynamics on back-contact PSCs and provide the basis for a new route to high-performance back-contact perovskite optoelectronic devices at low cost.     

Molecular Dynamics Simulations of Sulfobetaine-Type Zwitterionic Surfactant at the Decane/Water Interface

Automated Topology Builder (ATB) and GAMESS (US) were used to build the model of a new sulfobetaine-type zwitterionic surfactant. And a serious of molecular dynamics simulations of the new sulfobetaine-type zwitterionic surfactant were performed at the decane/water interface by GROMACS, the influence of surfactant structure to the interfacial properties was investigated. The results show that the surfactant molecules can adsorb at the decane/water interface closely and reduce the interfacial tension significantly between decane and water. In another word, the model of the sulfobetaine-type zwitterionic surfactant is correct. The minimum interfacial tension could reach up to 1.6 mN · m^?1 when the number of surfactants was up to 134, which corresponds to the critical micelle concentration and consistent with the experimental values of the system.     

Production of Biodiesel Through Esterification Reaction Using Choline Exchanging Polytungstoboronic Acids as Temperature-Responsive Catalysts

High proton content polytungstoboronic acid H₇BW₁₁TiO₄₀ (abbreviated as H₇BW₁₁Ti) had been prepared through titanium mono-substituted of H₅BW₁₂O₄₀, which was evaluated in esterification of palmitic acid with methanol. H₇BW₁₁Ti could promote esterification reaction with almost 100% conversion of 417 mol/mol h TOF within very short time of 1 h at methanol/acid ratio of 25:1 under reaction temperature of 65?°C, which was attributed to the higher Brønsted acidity and cooperation of Lewis acidic site generating from Ti substituent. Limitation by its homogeneous performance, solidification of H₇BW₁₁Ti was designed via partial exchanging protons with choline cation (abbreviated as Ch⁺) to prepare a series of [(CH₃)₃NCH₂CH₂OH]_nH_7?nBW₁₁TiO₄₀ (abbreviated as Ch_nH_7?nBW₁₁Ti, n?=?0?~?7). Among all solid catalysts, the highest efficiency had been achieved by with 99.0% conversion and 429 mol/mol h TOF within 50 min at 65?°C at methanol/acid ratio of 15:1. The comparable activity was attributed to the cooperation of Ch⁺—self-assembling to form nanoreactor with amphiphilic surrounding to concentrate substrates and to resist to water-poison, temperature-responsive property to control form changing between heterogeneous to homogenous. This temperature-responsive HPA catalyst was available for production of biodiesel through esterification reaction. In addition, Separation of such heteropolyacid catalysts was easy by the lowering the reaction temperature to room temperature without appreciable loss of its high performance, which were reused for more than six times.     

Spectrum of the -Neumann Laplacian on polydiscs

The spectrum of the -Neumann Laplacian on a polydisc in is explicitly computed. The calculation exhibits that the spectrum consists of eigenvalues, some of which, in particular the smallest ones, are of infinite multiplicity.

     

Synthesis of magnetic dual‐template molecularly imprinted nanoparticles for the specific removal of two high‐abundance proteins simultaneously in blood plasma

Novel core–shell dual‐template molecularly imprinted superparamagnetic nanoparticles were synthesized using bovine hemoglobin and bovine serum albumin as the templates for the efficient depletion of these two high‐abundance proteins from blood plasma for the first time. The preparation process combined surface imprinting technique and a two‐step immobilized template strategy. The obtained polymers were fully characterized by transmission electron microscopy, X‐ray diffraction, Fourier transform infrared spectroscopy, and vibrating sample magnetometry. The results showed that the as‐synthesized nanomaterials possessed homogeneous and thin imprinted shells with a thickness of about 5 nm, stable crystalline phase, and superparamagnetism. The binding performance of the imprinted polymers was investigated through a series of adsorption experiments, which indicated that the products had satisfactory recognition ability for bovine hemoglobin and bovine serum albumin. The resultant nanoparticles were also successfully applied to simultaneously selective removal of two proteins from a real bovine blood sample.     

Emergence of a Radical-Stabilizing Metal–Organic Framework as a Radio-photoluminescence Dosimeter

Radio-photoluminescence (RPL) materials display a distinct radiation-induced permanent luminescence center, and therefore find application in the detection of ionizing radiation. The current inventory of RPL materials, which were discovered by serendipity, has been limited to a small number of metal-ion-doped inorganic materials. Here we document the RPL of a metal–organic framework (MOF) for the first time: X-ray induced free radicals are accumulated on the organic linker and are subsequently stabilized in the conjugated fragment in the structure, while the metal center acts as the X-ray attenuator. These radicals afford new emission features in both UV-excited and X-ray excited luminescence spectra, making it possible to establish linear relationships between the radiation dose and the normalized intensity of the new emission feature. The MOF-based RPL materials exhibit advantages in terms of the dose detection range, reusability, emission stability, and energy threshold. Based on a comprehensive electronic structure and energy diagram study, the rational design and a substantial expansion of candidate RPL materials can be anticipated.     

The study of green laser performances by using composite crystals of different initial transmissions

This paper reported a passively Q-switched green laser of LD pumped linear cavity structure by using Nd:YAG/Cr⁴⁺:YAG composite crystal and the type II phase matching KTP crystal. The dependence of average output power, pulse width and pulse repetition rate on pump power at different initial transmissions of Cr⁴⁺:YAG were measured and analyzed. With Cr⁴⁺:YAG of 80% initial transmission, under pump power of 13.97 W, the output average power is up to 681 mW, with pulse width of 200 ns and pulse repetition rate of 9.1 kHz. The laser operates in a fundamental mode.