电化学氧化脱氢交叉偶联构建C―N键——电化学技术在有机化学实验教学中的设计与探索

将绿色电化学合成策略引入教学,通过电化学氧化偶联构建C―N键,实现了芳胺对位高选择性胺化,并通过循环伏安法对反应机理进行探索。此方案为科研转化的、开放性综合有机化学实验。反应以直流恒流电为电源,在室温空气条件下进行,首先以吩噻嗪和N,N-二甲基苯胺为模板底物,对电流、电量和电解质三个影响因素进行考察;确定最优条件后接着考察芳胺的适用性;最后通过循环伏安法对反应规律进行探索。实验深入融合贯穿了前沿科研成果的科学思路与创新理念,通过实验的开展,可以提升学生专业综合素质、激发学生创新意识。

Prevention of urinary tract infection using a silver alloy hydrogel-coated catheter in critically ill patients: A single-center prospective randomized controlled study

Background:A new type of silver alloy hydrogel-coated(SAH)catheter has been shown to prevent bacterial adhesion and colonization by generating a microcurrent,and to block the retrograde infection pathway.However,these have only been confirmed in ordinary patients.This study aims to evaluate the effectiveness of a SAH catheter for preventing urinary tract infections in critically ill patients.Methods:This was a prospective single-center,single-blind,randomized,controlled study.A total of 132 patients requiring indwelling catheterization in the intensive care unit(ICU)of the First Affiliated Hospital of the University of Science and Technology of China between October 2022 and February 2023 and who met the study inclusion/exclusion criteria were randomly divided into two groups.Patients in the SAH catheter group received a SAH catheter,while patients in the conventional catheter group received a conventional siliconized latex Foley catheter.The main outcome measure was the incidence of catheter-associated urinary tract infections(CAUTIs).Secondary outcome indicators included urine positivity for white blood cells and positive urine cultures on 3 days,7 days,10 days,and 14 days after catheterization,number of viable bacteria in the catheter biofilm on day 14,pathogenic characteristics of positive urine cultures,length of ICU stay,overall hospital stay,ICU mortality,and 28-day mortality.All the data were compared between the two groups.Results:A total of 68 patients in the conventional catheter group and 64 patients in the SAH catheter group were included in the study.On day 7 after catheter placement,the positivity rate for urinary white blood cells was significantly higher in the conventional catheter group than in the SAH catheter group(33.8%vs.15.6%,P=0.016).On day 10,the rates of positive urine cultures(27.9%vs.10.9%,P=0.014)and CAUTIs(22.1%vs.7.8%,P=0.023)were significantly higher in the conventional catheter group than in the SAH catheter group.On day 14,the numbers of viable bacteria isolated from the catheter tip([3.21±1.91]×10^(6) colony-forming units[cfu]/mL vs.[7.44±2.22]×10^(4) cfu/mL,P<0.001),balloon segment([7.30±1.99]×10^(7) cfu/mL vs.[3.48±2.38]×10^(5) cfu/mL,P<0.001),and tail section([6.41±2.07]×10^(5) cfu/mL vs.[8.50±1.46]×10^(3) cfu/mL,P<0.001)were significantly higher in the conventional catheter group than in the SAH catheter group.The most common bacteria in the urine of patients in both groups were Escherichia coli(n=13)and Pseudomonas aeruginosa(n=6),with only one case of Candida in each group.There were no significant differences between the two groups in terms of ICU hospitalization time,total hospitalization time,ICU mortality,and 28-day mortality.Conclusion:SAH catheters can effectively inhibit the formation of catheter-related bacterial biofilms in critically ill patients and reduce the incidence of CAUTIs,compared with conventional siliconized latex Foley catheters;however,regular replacement of the catheter is still necessary.

De Novo Design of Polymeric Carrier to Photothermally Release Singlet Oxygen for Hypoxic Tumor Treatment

Intratumoral hypoxia extremely limits the clinic applications of photodynamic therapy(PDT).Endoperoxides allow thermally releasing singlet oxygen(1O_(2))in a defned quantity and ofer promising opportunities for oxygen-independent PDT treatment of hypoxic tumors.However,previous composite systems by combining endoperoxides with photothermal reagents may result in unpredicted side efects and potential harmful impacts during therapy in vivo.Herein,we de novo design an all-in-one polymer carrier,which can photothermally release 1O_(2).Te strategy has been demonstrated to efectively enhance the production of 1O_(2) and realize the photodamage in vitro,especially in hypoxic environment.Additionally,the polymer carrier accumulates into tumor afer intravenous injection via the enhanced permeation and retention efects and accelerates the oxygen-independent generation of 1O_(2) in tumors.Te oxidative damage results in good inhibitory efect on tumor growth.Realization of the strategy in vivo paves a new way to construct photothermal-triggered oxygen-independent therapeutic platform for clinical applications.

A ratiometric fluorescent sensor for tracking Cu(Ⅰ) fluctuation in endoplasmic reticulum

A two-photon ratiometric fluorescent sensor for Cu^+ in endoplasmic reticulum(ER), CNSB, was developed via coumarin/ASBD integration based on FRET mechanism. In solution, CNSB shows reversible, highly-specific ratiometric response to Cu^+ .Moreover, CNSB exhibits suitable K_d value, suggesting the possibility of detecting Cu^+ in the living cells. The probe can enter the MCF-7 cells easily and specifically locates in the ER. The highly specific ratiometric response of CNSB toward Cu^+ in MCF-7 cells provides the sensor the capacity to visualize both exogenous and endogenous Cu^+ in the ER via fluorescence imaging.Next, CNSB was utilized to detect the fluctuation and distribution of Cu^+ under ER stress in MCF-7 cells, which confirmed directly the relationship between Cu^+ enhancement and ER stress. Meanwhile, the two-photon ability of coumarin facilitated the sensor to visualize Cu^+ fluctuation via two-photon fluorescence imaging. In addition, the spatial distribution of Cu^+ in the heart slice of the 14-day-old rat was demonstrated using CNSB. This study demonstrates the promising potential of CNSB in clarifying the Cu^+ -dependent signaling in the ER stress-related diseases.