Beckmann重排反应的综合性实验设计与教学应用

Beckmann反应是含有羰基的醛、酮与羟胺反应生成有机肟,在催化剂作用下发生重排,在有机合成中具有重要意义。针对实验教学中有机肟Beckmann重排反应的实验原理直观性不足、反应机理佐证性欠缺等问题,通过二苯甲酮与盐酸羟胺反应生成二苯甲酮肟,多聚磷酸催化分子重排反应生成苯甲酰基苯胺为案例,交叉运用无机化学、分析化学、仪器分析的知识和实验技能,测定阶段产物和终产物的熔点、红外光谱、核磁共振谱并表征其结构,将宏观理化性质与微观结构相结合,解析和验证反应机理,达到Beckmann重排反应实验原理直观、反应机理佐证完善的结果,实验的综合设计与交叉创新提升了Beckmann重排实验的教学效果,并激发学生的创新意识。本文既可为肟类Beckmann重排反应的综合性、设计性实验提供借鉴,也可为教材及实验的改进提供有价值的参考。

Associations between remnant cholesterol levels and mortality in patients with diabetes

BACKGROUND Dyslipidemia is frequently present in patients with diabetes.The associations of remnant cholesterol and mortality remains unclear in patients with diabetes.AIM To explore the associations of remnant cholesterol with all-cause and cardiovas-cular mortality in patients with diabetes.METHODS This prospective cohort study included 4740 patients with diabetes who par-ticipated in the National Health and Nutrition Examination Survey from 1999 through 2018.Remnant cholesterol was used as the exposure variable,and all-cause and cardiovascular mortality were considered outcome events.Outcome data were obtained from the National Death Index,and all participants were followed from the interview date until death or December 31,2019.Multivariate proportional Cox regression models were used to explore the associations between exposure and outcomes,in which remnant cholesterol was modeled as both a categorical and a continuous variable.Restricted cubic splines(RCSs)were calculated to assess the nonlinearity of associations.Subgroup(stratified by sex,age,body mass index,and duration of diabetes)and a series of sensitivity analyses were performed to evaluate the robustness of the associations.RESULTS During a median follow-up duration of 83 months,1370 all-cause deaths and 389 cardiovascular deaths were documented.Patients with remnant cholesterol levels in the third quartile had a reduced risk of all-cause mortality[hazard ratio(HR)95%confidence interval(CI):0.66(0.52-0.85)];however,when remnant cholesterol was modeled as a continuous variable,it was associated with increased risks of all-cause[HR(95%CI):1.12(1.02-1.21)per SD]and cardiovascular[HR(95%CI):1.16(1.01-1.32),per SD]mortality.The RCS demonstrated nonlinear associations of remnant cholesterol with all-cause and cardiovascular mortality.Subgroup and sensitivity analyses did not reveal significant differences from the above results.CONCLUSION In patients with diabetes,higher remnant cholesterol was associated with increased risks of all-cause and cardiovascular mortality,and diabetes patients with slightly higher remnant cholesterol(0.68-1.04 mmol/L)had a lower risk of all-cause mortality.

Intelligent extraction of road cracks based on vehicle laser point cloud and panoramic sequence images

In light of the limited efficacy of conventional methods for identifying pavement cracks and the absence of comprehensive depth and location data in two-dimensional photographs,this study presents an intelligent strategy for extracting road cracks.This methodology involves the integration of laser point cloud data obtained from a vehicle-mounted system and a panoramic sequence of images.The study employs a vehicle-mounted LiDAR measurement system to acquire laser point cloud and panoramic sequence image data simultaneously.A convolutional neural network is utilized to extract cracks from the panoramic sequence image.The extracted sequence image is then aligned with the laser point cloud,enabling the assignment of RGB information to the vehicle-mounted three dimensional(3D)point cloud and location information to the two dimensional(2D)panoramic image.Additionally,a threshold value is set based on the crack elevation change to extract the aligned roadway point cloud.The three-dimensional data pertaining to the cracks can be acquired.The experimental findings demonstrate that the use of convolutional neural networks has yielded noteworthy outcomes in the extraction of road cracks.The utilization of point cloud and image alignment techniques enables the extraction of precise location data pertaining to road cracks.This approach exhibits superior accuracy when compared to conventional methods.Moreover,it facilitates rapid and accurate identification and localization of road cracks,thereby playing a crucial role in ensuring road maintenance and traffic safety.Consequently,this technique finds extensive application in the domains of intelligent transportation and urbanization development.The technology exhibits significant promise for use in the domains of intelligent transportation and city development.

Targeting epicardial adipose tissue:A potential therapeutic strategy for heart failure with preserved ejection fraction with type 2 diabetes mellitus

Heart failure with preserved ejection fraction(HFpEF)is a heterogeneous syndrome with various comorbidities,multiple cardiac and extracardiac pathophysiologic abnormalities,and diverse phenotypic presentations.Since HFpEF is a heterogeneous disease with different phenotypes,individualized treatment is required.HFpEF with type 2 diabetes mellitus(T2DM)represents a specific phenotype of HFpEF,with about 45%-50% of HFpEF patients suffering from T2DM.Systemic inflammation associated with dysregulated glucose metabolism is a critical pathological mechanism of HFpEF with T2DM,which is intimately related to the expansion and dysfunction(inflammation and hypermetabolic activity)of epicardial adipose tissue(EAT).EAT is well established as a very active endocrine organ that can regulate the pathophysiological processes of HFpEF with T2DM through the paracrine and endocrine mechanisms.Therefore,suppressing abnormal EAT expansion may be a promising therapeutic strategy for HFpEF with T2DM.Although there is no treatment specifically for EAT,lifestyle management,bariatric surgery,and some pharmaceutical interventions(anti-cytokine drugs,statins,proprotein convertase subtilisin/kexin type 9 inhibitors,metformin,glucagon-like peptide-1 receptor agonists,and especially sodium-glucose cotransporter-2 inhibitors)have been shown to attenuate the inflammatory response or expansion of EAT.Importantly,these treatments may be beneficial in improving the clinical symptoms or prognosis of patients with HFpEF.Accordingly,well-designed randomized controlled trials are needed to validate the efficacy of current therapies.In addition,more novel and effective therapies targeting EAT are needed in the future.

康柏西普联合多波长多点扫描激光治疗早期PDR的疗效

目的:观察玻璃体腔内注射康柏西普联合多波长多点扫描激光全视网膜光凝(PRP)治疗早期PDR的临床效果。方法:回顾性病例对照研究。选取我院眼科确诊为早期PDR的患者80例102眼,排除视网膜纤维增殖膜和玻璃体积血。A组(单纯PRP组)48例60眼,B组(康柏西普联合PRP组)32例42眼,激光治疗前3～5d玻璃体腔内注射康柏西普0.5mg。两组患者均分两次采用多波长多点扫描激光完成PRP治疗,间隔时间3～7d。3mo后根据FFA结果必要时补充激光。术后至少随访3mo,观察患者治疗效果和相关并发症、PRP术后3mo时BCVA,以及两组患者PRP术后1wk,1、3mo时黄斑中心视网膜厚度(CMT)变化。结果:A组患者玻璃体积血、黄斑水肿或原黄斑水肿加重的发生率均高于B组(P<0.05)。术后3mo时,A组治疗总有效率为73.3%,B组总有效率为90.5%(P<0.05)。两组患者治疗后不同时间点CMT均有差异(P<0.05)。结论:康柏西普联合多波长多点扫描激光PRP治疗早期PDR可减少激光术中玻璃体积血的发生率,减轻黄斑水肿,改善患者视力,其作用优于单纯PRP。

3D-Slicer软件在神经内镜经鼻蝶入路垂体腺瘤手术中的应用

目的探讨3D-Slicer软件辅助神经内镜经鼻蝶入路垂体腺瘤手术的疗效与价值。方法28例垂体腺瘤患者行头颅CT和头颅MRI检查,将影像数据输入3D-Slicer软件,对蝶窦、鞍区骨性结构、垂体腺瘤及颈内动脉、视神经结构进行三维重建,并行术前规划,判断神经血管和肿瘤的空间关系,模拟磨除鞍底的过程,将重建图像与术中图像进行比较,评价两者吻合程度,记录术后并发症和疗效。结果所有患者的三维重建图像中,蝶窦、鞍区骨性结构、垂体腺瘤及神经血管均可清晰显示,与术中内镜下实际图像高度匹配,能准确识别重要结构,并规划出鞍底骨窗的合适范围。所有患者手术过程顺利,术后均未发生严重并发症。结论3D-Slicer软件运用于神经内镜下经鼻蝶入路垂体腺瘤手术,有助于术前明确显示蝶窦、蝶鞍、肿瘤与神经血管的空间关系,可帮助提高手术安全性与手术效率。

酞菁蓝B合成综合实验设计与教学实践

以邻苯二甲酸酐、尿素、氯化亚铜为原料经氨解、取代、络合、缩合反应生成酞菁蓝B,通过镜像显微镜观察产品的形态,红外/紫外光谱法表征官能团结构和解析谱学特征峰,并考查产品的光稳定性。通过该实验将不同化学单元操作汇集为知识链,不同类型反应融汇贯通,达到了创新意识启发、综合知识提升及实践技能提高的目的。

生物质裂解产物的制备及HPLC检测其成分的虚拟仿真实验开发

为提高信息化背景下高校实验教学质量和实践育人水平,解决实习实训环节开展困难的问题,开发了生物质快速热解及HPLC检测其成分的虚拟仿真实验平台。实验依据生物质快速热解制取裂解产物的工厂实际操作流程,结合高效液相检测化学成分的仪器分析实验过程,将虚拟实验划分为生物质样品预处理系统、生物质快速热解系统、生物油提质系统和复杂成分的大型仪器HPLC测定四个子系统,通过仿真使生物质裂解车间"真实"再现。该虚拟仿真实验充分将农林院校优势特色农林专业广泛涉及的生物质利用与基础化学课程(如有机化学、仪器分析、化工原理等)融合贯通,有利于全面提升人才培养质量,具有参考价值。

Nicotinamide overload may play a role in the development of type 2 diabetes

AIM： To investigate whether nicotinamide overload plays a role in type 2 diabetes. METHODS： Nicotinamide metabolic patterns of 14 diabetic and 14 non-diabetic subjects were compared using HPLC. Cumulative effects of nicotinamide and N^1-methylnicotinamide on glucose metabolism, plasma HzO2 levels and tissue nicotinamide adenine dinucleotide （NAD） contents of adult Sprague-Dawley rats were observed. The role of human sweat glands and rat skin in nicotinamide metabolism was investigated using sauna and burn injury, respectively. RESULTS： Diabetic subjects had significantly higher plasma N^1-methylnicotinamide levels 5 h after a 100-mg nicotinamide load than the non-diabetic subjects （0.89 ± 0.13 μmol/L vs 0.6 ± 0.13 μmol/L, P 〈 0.001）. Cumulative doses of nicotinamide （2 g/kg） significantly increased rat plasma Nl-methylnicotinamide concentrations associated with severe insulin resistance, which was mimicked by Nl-methy-Inicotinamide. Moreover, cumulative exposure to N^1- methylnicotinamide （2 g/kg） markedly reduced rat muscle and liver NAD contents and erythrocyte NAD/ NADH ratio, and increased plasma H2O2 levels. Decrease in NAD/NADH ratio and increase in H2O2 generation were also observed in human erythrocytes after exposure to N^1-methylnicotinamide in vitro. Sweating eliminated excessive nicotinamide （5.3-fold increase in sweat nicotinamide concentration 1 h after a 100-mg nicotinamide load）. Skin damage or aldehyde oxidase inhibition with tamoxifen or olanzapine, both being notorious for impairing glucose tolerance, delayed N^1- methylnicotinamide clearance. CONCLUSION： These findings suggest that nicotinamide overload, which induced an increase in plasma N^1- methylnicotinamide, associated with oxidative stress and insulin resistance, plays a role in type 2 diabetes.

Sertoli cell and spermatogonial development in pigs

Background:Spermatogenesis is an intricate developmental process during which undifferentiated spermatogonia,containing spermatogonial stem cells(SSCs),undergo self-renewal and differentiation to generate eventually mature spermatozoa.Spermatogenesis occurs in seminiferous tubules within the testis,and the seminiferous tubules harbor Sertoli and germ cells.Sertoli cells are an essential somatic cell type within the microenvironment that support and steer male germ cell development,whereas spermatogonia are the primitive male germ cells at the onset of spermatogenesis.While the developmental progression of Sertoli cells and spermatogonia has been well established in mice,much less is known in other mammalian species including pigs.Results:To acquire knowledge of Sertoli cell and spermatogonial development in pigs,here we collected as many as nine ages of Duroc porcine testes from the neonate to sexual maturity,i.e.,testes from 7-,30-,50-,70-,90-,110-,130-,150-and 210-day-old boars,and performed histological and immunohistochemical analyses on testis sections.We first examined the development of spermatogenic cells and seminiferous tubules in porcine testes.Then,by immunofluorescence staining for marker proteins(AMH,SOX9,DBA,UCHL1,VASA,KIT,Ki67 and/or PCNA),we delved into the proliferative activity and development of Sertoli cells and of spermatogonial subtypes(pro-,undifferentiated and differentiating spermatogonia).Besides,by immunostaining forβ-catenin and ZO-1,we studied the establishment of the blood-testis barrier in porcine testes.Conclusions:In this longitudinal study,we have systematically investigated the elaborate Sertoli cell and spermatogonial developmental patterns in pigs from the neonate to sexual maturity that have so far remained largely unknown.The findings not only extend the knowledge about spermatogenesis and testicular development in pigs,but also lay the theoretical groundwork for porcine breeding and rearing.

State of the art and practice of pavement anti-icing and de-icing techniques

Pavement snow and icing are worldwide problems, but effective countermeasures are just beginning to be developed in China. The two most common snow and ice removal methods are mechanical clearance and chemical melting, and the advantages and disadvantages of each approach are discussed here, including environmental and structural damage caused by corrosive snow melting agents. New developments in chemical melting agents and mechanical equipment are discussed, and an overview of alternative thermal melting systems is presented, including the use of geothermy and non-geothermal heating systems utilizing solar energy, electricity, conductive pavement materials, and infrared/microwave applications. Strategic recommendations are made for continued enhancement of public safety in snow and ice conditions.

Single-cell RNA-sequencing reveals the dynamic process and novel markers in porcine spermatogenesis

Background:Spermatogenesis is the process by which male gametes are formed from spermatogonial stem cells and it is essential for the reliable transmission of genetic information between generations.To date,the dynamic transcriptional changes of defined populations of male germ cells in pigs have not been reported.Results:To characterize the atlas of porcine spermatogenesis,we profiled the transcriptomes of~16,966 testicular cells from a 150-day-old pig testis through single-cell RNA-sequencing(scRNA-seq).The scRNA-seq analysis identified spermatogonia,spermatocytes,spermatids and three somatic cell types in porcine testes.The functional enrichment analysis demonstrated that these cell types played diverse roles in porcine spermatogenesis.The accuracy of the defined porcine germ cell types was further validated by comparing the data from scRNA-seq with those from bulk RNA-seq.Since we delineated four distinct spermatogonial subsets,we further identified CD99 and PODXL2 as novel cell surface markers for undifferentiated and differentiating spermatogonia,respectively.Conclusions:The present study has for the first time analyzed the transcriptome of male germ cells and somatic cells in porcine testes through scRNA-seq.Four subsets of spermatogonia were identified and two novel cell surface markers were discovered,which would be helpful for studies on spermatogonial differentiation in pigs.The datasets offer valuable information on porcine spermatogenesis,and pave the way for identification of key molecular markers involved in development of male germ cells.

Cobalt-catalyzed Photochemical Methoxycarbonylation of Olefins with Carbon Dioxide under Ambient Conditions

The methoxycarbonylations of cyclohexene and 1-decene with CO2 can take place under ambient conditions by catalysis of [Co]([Co]=Co(acac)(2), Co(OAc)(2), CoCl2) in the presence of ultraviolet irradiation.

Targeting Hypoxic Tumors with Hybrid Nanobullets for Oxygen-Independent Synergistic Photothermal and Thermodynamic Therapy

Hypoxia is a feature of solid tumors and it hinders the therapeutic efficacy of oxygen-dependent cancer treatment.Herein,we have developed all-organic oxygen-independent hybrid nanobullets ZPA@HA-ACVA-AZ for the“precise strike”of hypoxic tumors through the dual-targeting effects from surface-modified hyaluronic acid(HA)and hypoxia-dependent factor carbonic anhydrase IX(CA IX)-inhibitor acetazolamide(AZ).The core of nanobullets is the special zinc(II)phthalocyanine aggregates(ZPA)which could heat the tumor tissues upon 808-nm laser irradiation for photothermal therapy(PTT),along with the alkyl chain-functionalized thermally decomposable radical initiator ACVA-HDA on the side chain of HA for providing oxygen-independent alkyl radicals for ablating hypoxic cancer cells by thermodynamic therapy(TDT).The results provide important evidence that the combination of reverse hypoxia hallmarks CA IX as targets for inhibition by AZ and synergistic PTT/TDT possess incomparable therapeutic advantages over traditional(reactive oxygen species(ROS)-mediated)cancer treatment for suppressing the growth of both hypoxic tumors and their metastasis.

Synthesis of α,β-Unsaturated Ketones using Potassium fluoridealumina Catalyst by Microwave Irradiation

Microwave irradiation can accelerate the rate of the synthetic reaction of α,β-unsaturated ketones by using KF-Al2O3 as catalyst. The rate enhancement of the reaction is 360-860 fold.

La-doped NiFe-LDH coupled with hierarchical vertically aligned MXene frameworks for efficient overall water splitting

The development of stable electrocatalysts with high hydrogen and oxygen evolution reactions (HER and OER) activity in alkaline electrolytes is critical to renewable energy conversion technologies,such as electrochemical water splitting.In this work,a novel strategy for engineering water splitting electrocatalysts in alkaline electrolyte was developed by synergistically coupling La-doped Ni Fe-layered double hydroxides (Ni Fe-LDH) nanosheets onto three-dimensional (3D) vertically aligned MXene nanosheets on macroporous nickel foam (NF) substrates (Ni Fe La-LDH/v-MXene/NF).The electrocatalytic performance of the prepared Ni Fe La-LDH/v-MXene/NF is enhanced by the synergy of strong electronic interaction among multiple metal centers and unique vertically aligned porous MXene with increased active surface area,accelerated reaction kinetics and improved water adsorption and dissociation ability.To reach the commercially required current density (500 m A cm^(-2)),the Ni Fe La-LDH/v-MXene/NF exhibits greatly reduced overpotentials of 233 and 255 m V for HER and OER,respectively,along with excellent durability.Moreover,an alkaline electrolyzer driven by Ni Fe La-LDH/v-MXene/NF delivers a lower cell voltage(1.71 V) compared with that of Pt/C-RuO_(2) couple to achieve the current density of 500 m A cm^(-2).

Dynamic transcriptional atlas of male germ cells during porcine puberty

DEAR EDITOR,Spermatogenesis is the process by which male gametes are formed from spermatogonial stem cells(SSCs)and it is essential for the reliable transmission of genetic information between generations.After birth,prospermatogonia(ProSG)give rise to SSCs.While mouse spermatogenesis is relatively well studied,we are only just beginning to unravel this process in larger animals.Here,we analyzed key developmental transitions and differentiation trajectories by profiling neonatal,juvenile,and adult testes through single-cell sequencing(scRNA-seq).We found that SSCs were established at 30 days old,and that CDH1 was a novel cell surface marker for porcine ProSG and undifferentiated spermatogonia.

A comparative study of the therapeutic effect in two protocols: video-assisted thoracic surgery combined with laparoscopy versus right open transthoracic esophagectomy for esophageal cancer management

Objective: The aim was to evaluate the best intra-thoracoscopic surgery technique between video-assisted thoracic surgery (VATS) combined with laparoscopy and right open transthoracic esophagectomy, in patients with esophageal cancer. Methods: From November 2006 to May 2008, 221 patients with esophageal cancer were enrolled in this study, prospective randomized in two groups. 111 patients were performed the VATS technique (Experimental group), whereas in the other 110 patients esophagectomy was adopted by thoracotomy (Control group). Results: The time consuming of Experimental group was 272.3 min in average with a standard deviation(std) of 57.9, and it was 218.7 min in average with std of 91.0 in the control group (P=0.000). The operative blood loss was 219.7±194.4 mL in the Experimental group, compared with 590.0±324.4 mL in the control group, with significant difference (P=0.000). Postoperative hospital stay of Experimental group was 9.6±1.7d, and it was 11.4±2.3d in the control group (P=0.000). There was no-delayed union of incision in the Experimental group, but 6.36% in the control group (P=0.007). The disorder of gastric emptying occurred 0.9% in the Experimental group, whereas 6.4% in the Control group. There was no significant difference in survival curves and rates (P=0.555). Conclusion: There were several advantages of VATS technique, such as reduced hemorrhage, better recovery, few complications, and great number of lymph node dissection, although there was no significant difference in long-term survival rate. Thus the VATS combined with laparoscopy technique was worthy of generalization in esophageal surgery with good prospects.

Lung carcinoma signaling pathways activated by smoking

Lung cancer is the leading cause of cancer death in men and women worldwide,with over a million deaths annually.Tobacco smoke is the major etiologic risk factor for lung cancer in current or previous smokers and has been strongly related to certain types of lung cancer,such as small cell lung carcinoma and squamous cell lung carcinoma.In recent years,there has been an increased incidence of lung adenocarcinoma.This change is strongly associated with changes in smoking behavior and cigarette design.Carcinogens present in tobacco products and their intermediate metabolites can activate multiple signaling pathways that contribute to lung cancer carcinogenesis.In this review,we summarize the smoking-activated signaling pathways involved in lung cancer.

Elemental sulfur upregulated testicular testosterone biosynthesis by associating with altered gut microbiota in mice

Elemental sulfur has been used as a traditional Chinese medicine to treat the late-onset hypogonadism and impotence without a clarified mechanism for many hundreds of years.In the present study,mice were received sulfur or distilled water for 35 days by daily intragastric gavage at a dose of 250 mg/kg body weight.Then,the serum testosterone level and genes associated with testicular testosterone biosynthesis(TTB)were detected.The gut microbiota was also analyzed by 16S rRNA gene sequencing.Serum testosterone level was significantly increased by 291.1%in sulfur-treated mice.The H2S levels in serum and feces were significantly increased.The expression of genes associated with TTB including StAR,p450c17,3β-HSD,and P450scc in testes were significantly upregulated by Sulfur and NaHS,suggesting that sulfur promotes TTB depending on H2S.In addition,sulfur increased the diversity of gut microbiota and the abundance of several bacteria associated with sulfur metabolism,including genus Prevotella,which might be positively associated with serum level of testosterone in boys.Five pathways including bile secretion,carotenoid biosynthesis,lipid biosynthesis proteins,propanoate metabolism,and biosynthesis of type II polyketide products,were identified to associate with sulfur.Together,our results suggested that sulfur upregulated testicular testosterone biosynthesis via H2S,which was associated with alteration of gut microbiota in mice.Our study highlights a mechanism for the treatment of late-onset hypogonadism and impotence by sulfur.