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With the deepening development of the Guangdong-Hong Kong-Macao Greater Bay Area, the water security situation is becoming increasingly tense and causing frequent illegal and criminal incidents on the water, which has brought great harm to the economy and people's lives in the Bay Area. On the surface of the public security analysis, the public security organs to the importance of the water police is the direct reason of the deterioration of the water security situation. The deep factors include the existing problems in the form of police organization form in the Pearl River Delta, the lack of police talents in foreign-related waters, the formation of mass prevention and mass governance network by unrelated people, the urgent need of water-related laws, and the fuzzy police organization form in water waters. The prevention and control of public security in waters should start from strengthening the legal standardization and unity construction of water area public security law enforcement, developing the academic education of water area police officers, cultivating professional water area police talents and strengthening the joint prevention and cooperation mechanism of public security in the Pearl River Delta region.

The monofunctionalized carbodefluorination of readily accessible CF3 groups is acknowledged as an attractive approach to the preparation of partially fluorinated molecules. However, their defluorinative difunctionalization remains a challenging and unmet goal. Herein, we report an unprecedented defluorinative carboimination of trifluoromethyl ketones via a strategy of silver carbene-initiated rearrangement, in which both C–F bond and carbonyl group of the trifluoromethyl ketones were functionalized simultaneously, thus providing a straightforward synthetic method for medicinally relevant α,α-difluoroimines. The current approach involves a silver carbene-initiated intramolecular cascade process by integrating successive cleavage of C–F bond and formation of C–C and C=N bonds on a single molecule entity, which differs relevantly from the stepwise mechanism of reported carbodefluorination of CF3 groups. Mechanistic studies disclose that silver catalysis plays a critical role, particularly in the stages of C–F bond cleavage and aza-Claisen rearrangement.

The polymer produced by photoinitiated bulk polymerization promotes intersystem crossing of luminescent dopants and switches on room-temperature organic afterglow.

The first example of dearomative [4 + 3] cycloaddition between furans and vinyl-N-sulfonylhydrazones as vinylcarbene precursors is reported. The merger of silver catalysis and easily decomposable vinyl-N-triftosylhydrazones enabled the efficient synthesis of a variety of skeletally and functionally diverse oxa-bridged seven-membered bicyclic compounds with complete and predictable stereoselectivity. The combination of experimental studies and DFT calculations disclosed that the silver-catalyzed reaction proceeds via a concerted [4 + 3] cycloaddition mechanism, rather than the generally accepted cyclopropanation / Cope rearrangement pathway by rhodium catalysis.

An efficient and practical method for the synthesis of benzyl azides from carbonyl compounds and commercially available TMSN3 was developed. The synthetic advantages are illustrated by gram-scale reaction and the synthesis of drug-like molecules.

A metal-free cycloaddition reaction of fluoroalkyl N-sulfonylhydrazones with arene-diazonium salts has been reported. This transformation represents the first general procedure to access mono-, di- and perfluoroalkyl tetrazole products.

A formal [4 + 3] cycloaddition of 1,3-dienes with alkenyl-N-triftosylhydrazones was developed using silver catalysis, producing a broad spectrum of complex 1,4-cycloheptadienes with high yields and predictable stereochemistry.

Building molecular complexity from simple feedstocks through peripheral and skeletal editing is central to modern organic synthesis. Nevertheless, a controllable strategy that can modify both the core skeleton and periphery of an aromatic heterocycle with a common substrate remains undeveloped, despite its potential to maximize structural diversity and applications. Here we report a fluoroalkyl carbene-initiated chemodivergent molecular editing of indoles, allowing both skeletal and peripheral editing by trapping electrophilic fluoroalkyl carbene generated in situ from fluoroalkyl N-triftosylhydrazones. A variety of fluorine-containing N-heterocyclic scaffolds could be efficiently achieved through the tunable chemoselective editing reactions at skeleton or periphery of the indole, including one-carbon insertion, C3−H gem-difluoroolefination, tandem cyclopropanation/N1−H gem-difluoroolefination, and cyclopropanation. Mechanistic experiments and computations have probed the reaction mechanism and the origins of chemo- and regioselectivity.

The construction of allylic quaternary sp

Medical research is important to scientific progress and medical education. Institutions worldwide have sought to increase student involvement in research such as clinician-scientists training programs, while little is known about how medical undergraduates perceive research. A cross-sectional study was conducted in Chongqing Medical University, Chongqing, China, with first-fourth year undergraduates. An online, anonymous, and self-rating 5-point Likert questionnaire was conducted to investigate medical undergraduates' demographic characteristics and assess motivation, self-efficacy, perception, curiosity, and barriers regarding medical research. Content validity was checked with experts and face validity was checked for clarity and understanding of the questionnaire. The Cronbach's alpha coefficient of the questions ranged from 0.813 to 0.879. A total of 3273 medical undergraduates were surveyed, and 86.62% (2835) participants (male 962, female 1873) were identified as effective. Males scored higher than females on self-efficacy (p 0.001), perception (p = 0.017), and curiosity (p 0.001), and lower on barriers (p 0.001). The second year students are at the peak of their perception (p = 0.006) and lowest barrier scores (p = 0.003). Students with scientific research experience scored higher in motivation (p = 0.002), self-efficacy (p 0.001), perception (p 0.001), and curiosity (p 0.001). Lack of proper mentoring opportunity (86.2%) and knowledge (84.5%) were the main barriers in conducting research. Even though they have a positive perspective, only a few undergraduates enrolled in research. Medical universities should encourage faculties to supervise and guide undergraduates' projects, and provide feasible solutions for students to learn scientific knowledge and skills. It is vital to build a research-oriented environment and academic atmosphere.

We herein report the first example of an iminyl-radical-mediated formal 1,3-HAT/radical coupling cascade of vinyl azides leading to the synthesis of tetrasubstituted

The conversion of inexpensive aqueous ammonia (NH

An efficient method to prepare 3-functionalized oxetanes and azetidines has been realized by fluorocyclization of readily available 2-azidoallyl/2-alkoxyallyl alcohols and amines. Notably, this is the first example applying the fluorocyclization strategy to construct four-membered heterocycles. The pendant electron-donating group (-N

Diazo compounds and isocyanides are reactive functionalities and valuable building blocks commonly utilized in organic synthesis. Their cross-coupling for the synthesis of useful isolable ketenimin...

The objective of this study is to characterize the function of microRNA (miR)-124 in the process of coronary artery disease (CAD). Eighty patients, including 40 CAD patients and 40 non-CAD control patients were enrolled in this study. Atherosclerosis model was established in vivo in ApoE-/- mice and in vitro in RAW264.7 cells. Expression of miR-124 and p38 in patients, animal models and cell models were measured by qRT-PCR, western blot and immunohistochemistry assay. Overexpression or suppression of miR-124 was introduced in vitro and in vivo and the expression levels of p38, miR-124, pro- and anti-inflammatory cytokines, and pro- and anti-apoptotic factors were examined. Results showed that miR-124 was decreased, while p38 was increased in CAD patients and atherosclerosis models compared with control group. MiR-124 could target p38 by binding its 3’ untranslated region and negatively regulated the protein expression of p38. Overexpression of miR-124 increased the expression of anti-inflammatory cytokines, reduced the expression of pro- inflammatory cytokines, and inhibited macrophage apoptosis. MiR-124 overexpression may be a promising treatment for atherosclerosis and CAD via inhibiting p38.

Catheter ablation is less successful for non-paroxysmal atrial fibrillation (NPAF) according to numerous follow-up studies. The choice of ablation strategy for patients with NPAF remains controversial. The objective of the study was to explore the clinical efficacy of the “ICE-FIRE” ablation. Ninety NPAF patients were enrolled. Patients were randomly divided into RF (treated with circumferential pulmonary vein isolation (CPVI) and additional substrate modification by radiofrequency ablation) group and I-F (treated with CPVI by cryoablation and additional substrate modification by radiofrequency ablation) group. After CPVI and cardioversion to sinus rhythm, high-density mapping was performed. Eight-one of 90 participants restored to sinus rhythm. Seventy-four of 81 NPAF patients showed low-voltage zone. Substrates with low-voltage zone were targeted for further modification. Participants were followed at baseline, 3, 6, 9, and 12 months after the initial ablation. The I-F group shared more X-ray exposure (I-F, 264.4 ± 97.4 mGy; RF, 224.9 ± 62.0 mGy; P = 0.039) and less duration of the procedure (I-F, 150.3 ± 27.5 min; RF, 174.2 ± 38.5 min; P = 0.003) compared to RF group. The freedom from atrial arrhythmia recurrence at 12 months post-ablation was similar between the RF and I-F groups (RF, 57.1%; I-F, 71.8%; P = 0.197). However, I-F group experienced lower rehospitalization rate of AF recurrence (RF, 42.9%; I-F, 20.5%; P = 0.038). In NPAF patients requiring substrate mapping and modification, the “ICE-FIRE” ablation demonstrated non-inferior clinical efficacy and lower rehospitalization rate of AF recurrence when compared with pure radiofrequency ablation strategy.

A highly efficient and operationally simple method for the synthesis of 1,2-disulfonylethenes involving a hypervalent iodineI(iii) reagent to promote disulfonation of terminal alkynes has been developed. This protocol provides a facile and practical pathway to selectively access (E)-1,2-disulfonylethenes that features good functional group compatibility, easily available starting materials, excellent stereoselectivity, and good yields.

The first formal [4+3] cycloaddition of 1,3-dienes with vinyl-N-sulfonylhydrazones has been achieved by virtue of easily decomposable vinyl-N-triftosylhydrazones in the presence of silver catalysis. A series of acyclic and cyclic 1,3-dienes reacted effectively with silver(I) non-acceptor vinyl carbenes, including alkyl- and alkenyl-substituted carbenes, which are notoriously challenging, producing a broad spectrum of 1,4-cycloheptadienes with high yield and predictable stereochemistry. The products resulting from the herein described transformation include bridged and fused polycyclic systems, as well as the natural product dictyopterene C' and its isomer ectocarpene. The reaction mechanism and the origin of stereoselectivity were investigated via experimental work and density functional theory calculations.

A state-of-the-art tool in synthetic organic chemistry is a rhodium diazocarbene species, which despite its flexibility, is derived from expensive and highly reactive species. Here the authors present a methodology for C-H benzylation of ethers via an analogous silver carbene species, obtained from a more common metal and a more stable starting material. The insertion of carbenes into the alpha-C-H bonds of ethers represents one of the most powerful approaches to access polysubstituted alpha-branched ethers. However, intermolecular carbene insertions remain challenging, since current approaches are generally limited to the use of toxic and potentially explosive alpha-diazocarbonyl compounds. We now report a silver-catalyzed alpha-C-H benzylation of ethers using bench-stable N-triftosylhydrazones as safe and convenient carbene precursors. This approach is well suited for both inter- and intramolecular insertions to deliver medicinally relevant homobenzylic ethers and 5-8-membered oxacycles in good yields. The synthetic utility of this strategy is demonstrated by its easy scalability, broad scope with valuable functional groups, high regioselectivity, and late-stage functionalization of complex oxygen-containing molecules. The relative reactivities of different types of silver carbenes and C-H bonds were also investigated by experments and DFT calculations.

A high temporal waveform fidelity stimulated Brillouin scattering phase conjugate mirror (SBS-PCM) with high energy efficiency, based on a novel medium, Novec-7500, is proposed and practically achieved in this study. A theoretical analysis reveals that the temporal-domain waveform distortion is caused by the inherent pulse duration compression effect of the SBS, and this undesirable phenomenon can be significantly suppressed by decreasing the compression coefficient (CC afterwards), which is defined as the gain coefficient divided by the phonon lifetime, which coefficient and is identified as the key parameter for high waveform-fidelity in SBS-PCM. The feasibility of this approach was demonstrated experimentally, in which a reflected pulse with waveform symmetry equals to the pump and an average pulse duration of 0.974 τp (τp is the duration of pump) with an energy efficiency of over 90% was achieved using Novec-7500.

Background: Noninvasive diagnostic technologies that can dynamically monitor changes in liver inflammation are highly important for the management of chronic hepatitis B (CHB) patients and thus warrant further exploration. This study assessed the diagnostic efficacy of FibroScan for liver inflammation in CHB patients.Methods: A total of 1185 patients were selected, and ultrasound-guided liver biopsy was performed within one month after the FibroScan test. The liver stiffness measurement (LSM), the reliability criteria (IQR/M) of LSM, the quality of liver biopsy (complete portal area, PA), and the liver inflammation grades were the main observation items of this study. With liver biopsy as the control, the diagnostic efficacy of FibroScan for liver inflammation in CHB patients was evaluated by receiver operating characteristic (ROC) curve analysis.Results: Significant differences in the LSM of FibroScan were observed among different grades of liver inflammation (P10) served as the control, and the cutoff point and the area under ROC curves (AUCs) of the LSMs for different inflammation grades were as follows: G2, 8.6 kPa, 0.775; G3 9.8 kPa, 0.818; and G4, 11.0 kPa; 0.832. With LSM cutoff values of 8.6 kPa, 9.8 kPa and 11.0 kPa, FibroScan showed certain diagnostic value for CHB patients with G2, G3 and G4 liver inflammation, especially those with G4 inflammation. Conclusions: The results of this study preliminarily showed that, in addition to liver fibrosis, FibroScan could evaluate liver inflammation in CHB patients in a noninvasive manner.

We report herein the first example of the N3 radical-mediated azidosulfonylation of alkynes, affording the β-azidovinyl sulfone products with a broad substrate scope, excellent functional group compatibility, and high yield. DFT calculations suggest that the mechanism of the reaction proceeds through an unprecedented sequential N3 radical addition and sulfonyl radical coupling pathway.

The insertion of carbenes into the α-C-H bonds of ethers represents one of the most powerful approaches to access polysubstituted α-branched ethers. However, intermolecular carbene insertions remain challenging, since current approaches are generally limited to the use of toxic and potentially explosive α-diazocarbonyl compounds. We now report a silver-catalyzed α-C-H benzylation of ethers using bench-stable N-triftosylhydrazones as safe and convenient carbene precursors. This approach is well suited for both inter- and intramolecular insertions to deliver medicinally relevant homobenzylic ethers and 5-8-membered oxacycles in good yields. The synthetic utility of this strategy is demonstrated by its easy scalability, broad scope with valuable functional groups, high regioselectivity, and late-stage functionalization of complex oxygen-containing molecules. The relative reactivities of different types of silver carbenes and C-H bonds were also investigated by experments and DFT calculations.

A detailed study of the dissociation performance of structurally varied N-sulfonylhydrazones was described, and N-tfsylhydrazone was proved to be the best substrate to give the corresponding diazo compound at room temperature. N-Tfsylhydrazone is capable of releasing nonstabilized aryldiazomethane in a wide range of solvents in the presence of various commonly used bases under mild reaction conditions (−25 °C to 40 °C). The utility of the strategy is established by late-stage derivatization of bioactive molecules and several typically sensitive reactions, in which highly purified diazo compounds are required.

Summary Alkanes are an abundant and valuable resource for transformation into value-added fine chemicals. However, selective functionalization of specific C(sp3)–H bonds in alkanes for alkyl-alkyl bond formation is a significant challenge because of their intrinsic inertness and the small differences in reactivity among various C(sp3)–H bonds. Here, we report a silver-catalyzed site-selective C(sp3)–H benzylation of simple alkanes using N-triftosylhydrazones as a convenient carbene precursor, which enables the synthesis of high value-added alkylated aromatics. A one-pot two-step protocol starting from aldehydes was also realized, thereby constituting a formal reductive alkylation of aryl aldehydes by alkanes. Experimental investigations and DFT calculations reveal that the role of the [TpBr3Ag]2 catalyst is 3-fold: it modulates the carbene reactivity, inhibits carbene dimerization, and avoids over insertion of the product. All three aspects are crucial for the success of this first site-selective intermolecular insertion of donor carbenes into C(sp3)–H bonds of simple alkanes.