Using Electrodeposition of Carboxylated Chitosan for Green Preparation of Copper Nanoclusters and Nanocomposite Films

On the basis of coordinated electrodeposition of carboxylated chitosan(CCS),we presented a green method to prepare Cu NCs and Cu NCs/CCS nanocomposite films.The method shows a range of benefits,such as the convenient and eco-friendly process,mild conditions,and simple post-treatment.The experimental results reveal that a homogeneous deposited film(Cu NCs/CCS nanocomposite film)is generated on the Cu plate(the anode)after electrodeposition,which exhibits an obvious red florescence.The results from TEM observation suggest there are nanoparticles(with the average particle size of 2.3 nm)in the deposited film.Spectral analysis results both demonstrate the existence of Cu NCs in the deposited film.Moreover,the Cu NCs/CCS film modified electrode is directly created through electrodeposition of CCS,which enables promising application in the electrochemical sensing.By means of fluorescence properties of Cu NCs,the Cu NCs/CCS film also owns the potential in fluorescence detection.Therefore,this work builds a novel method for the green synthesis of Cu NCs,meanwhile it offers a convenient and new electrodeposition strategy to prepare polysaccharide-based Cu NCs nanocomposites for uses in functional nanocomposites and bioelectronic devices.

Enabling heterogeneous catalysis to achieve carbon neutrality: Directional catalytic conversion of CO_(2) into carboxylic acids

The increase in anthropogenic carbon dioxide(CO_(2))emissions has exacerbated the deterioration of the global environment,which should be controlled to achieve carbon neutrality.Central to the core goal of achieving carbon neutrality is the utilization of CO_(2) under economic and sustainable conditions.Recently,the strong need for carbon neutrality has led to a proliferation of studies on the direct conversion of CO_(2) into carboxylic acids,which can effectively alleviate CO_(2) emissions and create high-value chemicals.The purpose of this review is to present the application prospects of carboxylic acids and the basic principles of CO_(2) conversion into carboxylic acids through photo-,electric-,and thermal catalysis.Special attention is focused on the regulation strategy of the activity of abundant catalysts at the molecular level,inspiring the preparation of high-performance catalysts.In addition,theoretical calculations,advanced technologies,and numerous typical examples are introduced to elaborate on the corresponding process and influencing factors of catalytic activity.Finally,challenges and prospects are provided for the future development of this field.It is hoped that this review will contribute to a deeper understanding of the conversion of CO_(2) into carboxylic acids and inspire more innovative breakthroughs.

Carboxyl Ester Lipase Protects Against Metabolic Dysfunction-Associated Steatohepatitis by Binding to Fatty Acid Synthase

Carboxyl ester lipase(CEL),a pivotal enzyme involved in lipid metabolism,is recurrently mutated in obese mice.Here,we aimed to elucidate the functional significance,molecular mechanism,and therapeutic potential of CEL in metabolic dysfunction-associated steatohepatitis(MASH).Hepatocyte-specific carboxyl ester lipase gene(Cel)knockout(Cel^(DHEP))and wildtype(WT)littermates were fed with cholinedeficient high-fat diet(CD-HFD)for 16 weeks,or methionine-and choline-deficient diet(MCD)for three weeks to induce MASH.Liquid chromatography–mass spectrometry and co-immunoprecipitation were employed to identify the downstream targets of CEL.CD-HFD/MCD-fed WT mice received intravenous injections of CEL-adeno-associated viral,serotype 8(AAV8)to induce specific overexpression of CEL in the liver.We observed a decrease in CEL protein levels in MASH induced by CD-HFD or MCD in mice.Cel^(DHEP) mice fed with CD-HFD or MCD exhibited pronounced hepatic steatosis,inflammation,lipid peroxidation,and liver injury compared to WT littermates,accompanied by increased hepatic nuclear factor kappa-light-chain-enhancer of activated B cell(NF-jB)activation.Consistently,Cel knockdown in mouse primary hepatocytes and AML12 cells aggravated lipid accumulation and inflammation,whereas CEL overexpression exerted the opposite effect.Mechanistically,CEL directly bound to fatty acid synthase(FASN),resulting in reduced FASN SUMOylation,which in turn promoted FASN degradation through the proteasome pathway.Furthermore,inhibition of FASN ameliorated hepatocyte lipid accumulation and inflammation induced by Cel knockdown in vivo and in vitro.Hepatocyte-specific CEL overexpression using AAV8-Cel significantly mitigated steatohepatitis in mice fed with CD-HFD or MCD.CEL protects against steatohepatitis development by directly interacting with FASN and suppressing its expression for de novo lipogenesis.CEL overexpression confers a therapeutic benefit in steatohepatitis.

Carboxylic bacterial cellulose fiber-based hydrogel electrolyte with imidazole-type ionic liquid for dendrite-free zinc metal batteries

Aqueous zinc metal batteries are regarded as the most promising energy storage system due to their advantages of high safety,low cost,and high theoretical capacity.However,the growth of dendrites and the occurrence of side reactions hinder the development of zinc metal batteries.Despite previous attempts to design advanced hydrogel electrolytes,achieving high mechanical performance and ionic conductivity of hydrogel electrolytes has remained challenging.In this work,a hydrogel electrolyte with an ionic crosslinked network is prepared by carboxylic bacterial cellulose fiber and imidazole-type ionic liquid,following by a covalent network of polyacrylamide.The hydrogel electrolyte possesses a superior ionic conductivity of 43.76 mS cm^(−1),leading to a Zn^(2+)migration number of 0.45,and high mechanical performance with an elastic modulus of 3.48 GPa and an elongation at breaking of 38.36%.More importantly,under the anion-coordination effect of the carboxyl group in bacterial cellulose and[BF4]−in imidazole-type ionic liquid,the solvation sheath of hydrated Zn^(2+)ions and the nucleation overpotential of Zn plating are regulated.The results of cycled testing show that the growth of zinc dendrites is effectively inhibited and the generation of irreversible by-products is reduced.With the carboxylic bacterial cellulose-based hydrogel electrolyte,the Zn||Zn symmetric batteries offer good cyclability as well as Zn||Ti batteries.

AAV mediated carboxyl terminus of Hsp70 interacting protein overexpression mitigates the cognitive and pathological phenotypes of APP/PS1 mice

The E3 ubiquitin ligase,carboxyl terminus of heat shock protein 70(Hsp70)interacting protein(CHIP),also functions as a co-chaperone and plays a crucial role in the protein quality control system.In this study,we aimed to investigate the neuroprotective effect of overexpressed CHIP on Alzheimer’s disease.We used an adeno-associated virus vector that can cross the blood-brain barrier to mediate CHIP overexpression in APP/PS1 mouse brain.CHIP overexpression significantly ameliorated the performance of APP/PS1 mice in the Morris water maze and nest building tests,reduced amyloid-βplaques,and decreased the expression of both amyloid-βand phosphorylated tau.CHIP also alleviated the concentration of microglia and astrocytes around plaques.In APP/PS1 mice of a younger age,CHIP overexpression promoted an increase in ADAM10 expression and inhibitedβ-site APP cleaving enzyme 1,insulin degrading enzyme,and neprilysin expression.Levels of HSP70 and HSP40,which have functional relevance to CHIP,were also increased.Single nuclei transcriptome sequencing in the hippocampus of CHIP overexpressed mice showed that the lysosomal pathway and oligodendrocyte-related biological processes were up-regulated,which may also reflect a potential mechanism for the neuroprotective effect of CHIP.Our research shows that CHIP effectively reduces the behavior and pathological manifestations of APP/PS1 mice.Indeed,overexpression of CHIP could be a beneficial approach for the treatment of Alzheimer’s disease.

Amine-functionalized metal organic framework@graphene oxide as filler in PAEK-containing carboxyl group membrane for ultrafiltration with ultra-high permeability and strong fouling resistance

Achieving high fouling resistance and permeability using membrane separation technology in water treatment processes remains a challenge.In this work,a novel mixed-matrix membrane(MMM)(poly(arylene ether ketone)[PAEK]-containing carboxyl groups[PAEK-COOH]/UiO-66-NH_(2)@graphene oxide[GO])with superb fouling resistance and high permeability was prepared by the nonsolvent-induced phase separation method,by in-situ growth of UiO-66-NH_(2) on the GO layer,and by preparing hydrophilic PAEK-COOH.On the basis of the structure and performance analysis of the MMM,the maximum water flux reached 591.25 L·m^(-2)·h^(-1) for PAEK-COOH/UiO-66-NH_(2)@GO,whereas the retention rate for bovine serum albumin increased from 85.40%to 94.87%.As the loading gradually increased,the hydrophilicity of the MMMs increased,significantly enhancing their fouling resistance.The strongest anti-fouling ability observed was 94.74%,which was 2.02 times greater than that of the pure membrane.At the same time,the MMMs contained internal amide and hydrogen bonds during the preparation process,forming a cross-linked structure,which further enhanced the mechanical strength and chemical stability.In summary,the MMMs with high retention rate,strong permeability,and anti-fouling ability were successfully prepared.

Simultaneous Extraction of Carboxylated Celulose Nanocrystals and Nanofibrils via Citric Acid Hydrolysis--A Sustainable Route

In this study, cellulose nanocrystals(CNC) with surface carboxylic groups were prepared from bleached softwood pulp by hydrolysis with concentrated citric acid at concentrations of 60 wt%~80 wt%. The solid residues from acid hydrolysis were collected for producing cellulose nanofibrils(CNF) via post high-pressure homogenization. Citric acid could be easily recovered after hydrolysis reactions through crystallization due to its low water solubility or through precipitation as a calcium salt followed by acidification. Several important properties of CNC and CNF, such as dimension, crystallinity, surface chemistry, thermal stability, were evaluated. Results showed that the obtained CNC and CNF surfaces contained carboxylic acid groups that facilitated functionalization and dispersion in aqueous processing. The recyclability of citric acid and the carboxylated CNC/CNF give the renewable cellulose nanomaterial huge potential for a wide range of industrial applications. Furthermore, the resultant CNC and CNF were used as reinforcing agents to make sodium carboxymethyl cellulose(CMC) films. Both CNC and CNF showed reinforcing effects in CMC composite films. The tensile strength of CMC films increased by 54.3% and 85.7% with 10 wt% inclusion of CNC and CNF, respectively. This study provides detailed information on carboxylated nanocellulose prepared by critic acid hydrolysis; a sustainable approach for the preparation of CNC/CNF is of significant importance for their various uses.

Purifying chylous plasma by precluding triglyceride via carboxylated polyethersulfone microfiltration membrane

Precluding the excessive lipoproteins from plasma rapidly and effectively is highly needed for biomedical detection and reducing plasma product scrap in blood donation stations.The current centrifugation procedure is high-cost and time-consuming.Herein,we fabricated an anionic microfiltration polyethersulfone(PES)membrane modified by interface swelling and implanting of acrylic acid(AA)for screening out large particle lipoprotein chylomicron(CM)and adsorbing cationic very low-density lipoproteins(VLDL).To improve the separation efficiency,a two-stage filtration through carboxylated polyethersulfone microfiltration membranes with the mean pore size of 0.45 and 0.22μm respectively were conducted.Attenuated total reflection Fourier transform infrared technique(ATR-FTIR),water contact angle(WCA),Zeta potential and scanning electron microscope(SEM)were employed to characterize the modified membrane.To test the effectiveness of this membrane,plasma flux and concentration variation of plasma components were examined to study the purification effectiveness.Furthermore,the hemocompatibility of modified membranes was tested to confirm its practicability on bloodcontacting materials.The carboxylated polyethersulfone microfiltration membrane shows its promising potential application to purify chylous plasma.

Dispersive Ability of Carboxylated Cellulose Nanofibrils for Aqueous Monolayer Montmorillonite Dispersion:Influence of Na^(+) and Ca^(2+) Concentrations

Carboxylated cellulose nanofibrils(CNFs)have emerged as effective green dispersants for monolayer montmorillonite(MMT)dispersions.However,their dispersion capability is sensitive to the metal ion concentration in aqueous solutions.Hence,this study investigated the effects of Na^(+) and Ca^(2+) concentrations on the dispersive ability of carboxylated CNFs for monolayer MMTs in water.Quartz crystal microbalance with dissipation monitoring(QCM-D)and atomic force microscopy(AFM)were utilized to explore the interfacial interactions between the carboxylated CNFs and monolayer MMTs under different Na^(+) and Ca^(2+) concentrations.When the concentration of Na^(+) reached 0.1 mmol/L,the adhesion mass of carboxylated CNFs on MMT-coated wafer peaked at 24.47 mg/m^(2),higher than control sample(carboxylated CNF-dispersed monolayer MMT dispersion without metal ions,16.03 mg/m^(2)).Moreover,the electrostatic shielding effect promoted a better dispersion of monolayer MMTs by carboxylated CNF dispersant.With a further increase in the Na^(+) concentration,the surface charge of CNFs and MMTs would be reversed resulting from the improved electrostatic shielding effect,which weaken the dispersive ability of carboxylated CNFs.The addition of Ca^(2+) reduced the dispersive ability of carboxylated CNFs for monolayer MMTs,because Ca^(2+) required a lower concentration for the onset of charge reversal compared to Na^(+).This study provides interfacial scale insights into the influence of metal ion concentration on carboxylated CNF-dispersed monolayer MMT dispersions.It also provides a strategy to enhance the dispersive ability of carboxylated CNFs for monolayer MMTs.

Electrocarboxylation of CO_(2) with Organic Substrates:Toward Cathodic Reaction

Electrocarboxylation of carbon dioxide(CO_(2))using organic substrates has emerged as a promising method for the sustainable synthesis of value-added carboxylic acids due to its renewable energy source and mild reaction conditions.The reactivity and product selectivity of electrocarboxylation are highly dependent on the cathodic behavior,involving a sequence of electron transfers and chemical reactions.Hence,it is necessary to understand the cathodic reaction mechanisms for optimizing reaction performance and product distribution.In this work,a review of recent advancements in the electrocarboxylation of CO_(2)with organic substrates based on different cathodic reaction pathways is presented to provide a reference for the development of novel methodologies of CO_(2)electrocarboxylation.Herein,cathodic reactions are particularly classified into two categories based on the initial electron carriers(i.e.,CO_(2)radical anion and substrate radical anion).Furthermore,three cathodic pathways(ENE(N),ENED,and EDEN)of substrate radical anion-induced electrocarboxylation are discussed,which differ in their electron transfer sequence,substrate dissociation,and nucleophilic reaction,to highlight their implications on reactivity and product selectivity.

羧基化多壁碳纳米管修饰电极测定左氧氟沙星

探究了左氧氟沙星在羧基化多壁碳纳米管(c-MWCNTs)修饰电极上的电化学行为,并采用循环伏安法对左氧氟沙星含量进行了测定.结果表明,c-MWCNTs修饰电极对左氧氟沙星有明显的电催化作用;在pH值为5.0的NaH_(2)PO_(4)Na_(2)HPO_(4)缓冲溶液中,左氧氟沙星溶液的氧化峰电流与浓度在1×10^(-5)~4×10^(-4)mol/L范围内呈良好线性关系,相关系数为0.998,检出限为2.87×10^(-6)mol/L;在最优测试条件下,左氧氟沙星片剂的加标回收率为98.7%~103.0%,相对标准偏差为1.31%~3.99%(n=5);羧基化多壁碳纳米管修饰玻碳电极(c-MWCNTs/GCE)对左氧氟沙星有较好的电化学响应,灵敏度高,可用于药品中左氧氟沙星测定.

羧基化柚子皮吸附Cd^(2+)的性能与机制

为探索利用食品加工废弃物柚子皮制备一种重金属离子吸附材料的可行性,通过NaOH将柚子皮中甲酯化的羧基水解成羧酸,再利用TEMPO/次氯酸钠/溴化钠体系将柚子皮中C-6位伯羟基氧化成羧酸,制备出一种羧基化柚子皮吸附材料,同时采用FTIR、SEM-EDS和XPS对柚子皮和吸附Cd^(2+)前后的羧基化柚子皮进行表征,研究其吸附机制。结果表明羧基化柚子皮中羧基含量为2.34 mmol/g,是改性前的10.64倍,且可以有效地去除水溶液中Cd^(2+)。羧基化柚子皮吸附Cd^(2+)更符合Langmuir和伪二阶动力学模型,属于单层化学吸附,对Cd^(2+)的最大吸附量为76.16 mg/g,是改性前的5.81倍。羧基化柚子皮中羧基(-COO^(-))是吸附Cd^(2+)的功能性基团,吸附后形成羧酸镉,其中镉以Cd^(2+)的形式存在,与-COO^(-)的配位方式主要是双齿桥式,该吸附过程是一个阳离子(Na^(+)和Cd^(2+))交换的过程。

超声波辅助合成色酮-3-甲酸

以苯酚为原料,经傅克酰基化、甲酰化、水解三步反应制备了色酮-3-甲酸,总收率57.4%,产物纯度98.6%。甲酰化反应以3-(2-羟基苯基)-3-氧代丙酸甲酯0.05 mol为模型,考察了不同溶剂、甲酸钠用量、超声频率、超声功率、反应温度、反应时间的影响。研究结果表明最优化的反应条件为四氢呋喃作溶剂、甲酸钠与3-(2-羟基苯基)-3-氧代丙酸甲酯的用量摩尔比为1.5:1、超声频率50 kHz、超声功率550 W、温度60℃、反应11 h,该步反应收率为80.0%。

聚酰胺纳滤膜表面羧基密度调控及其抗污染性能

采用均苯三甲酰氯(TMC)、对苯二甲酰氯(IPC)与哌嗪进行界面聚合反应,制备了不同羧基密度的聚酰胺纳滤膜.研究了羧基密度对膜污染的影响,并对纳滤膜的镁-锂分离选择效果进行评估.结果表明,TMC纳滤膜的羧基密度是IPC纳滤膜的3倍,水通量分别为81.9 L/(m^(2)·h·MPa)和56.5 L/(m^(2)·h·MPa).TMC纳滤膜对硫酸镁、氯化钠的截留效果优于IPC纳滤膜,对卤水镁的截留率达82.66%,对锂的截留率为-27.82%,具有较好的镁-锂分离选择效果.膜污染结果显示,TMC纳滤膜的不可逆通量衰减指数是IPC纳滤膜的3倍,抗污染能力与膜面羧基密度成反比.结果证实了膜面羧基官能团在膜污染中的关键作用,为制备具备抗污染性和高镁-锂分离比的纳滤膜提供了新思路.

骨化三醇对老年骨质疏松性脊柱骨折病人PKP术后骨折愈合的影响

目的研究骨化三醇用于老年骨质疏松性椎体压缩性骨折(OVCF)病人经皮椎体后凸成形术(PKP)后治疗对骨折愈合和血清骨碱性磷酸酶(BALP)、Ⅰ型前胶原N-端前肽(PINP)、胶原羧基端肽β特殊序列(β-CTX)表达水平的影响。方法纳入2019—2020年我院接受PKP手术的106例OVCF病人为研究对象,并采用随机数表法均分为观察组和对照组,每组53例。对照组PKP术后给予钙剂+阿仑膦酸钠片进行治疗,观察组在此基础上加用骨化三醇进行治疗,2组疗程均为6个月,比较2组临床疗效、Cobb角、Oswestry功能障碍指数(ODI)、骨密度和骨代谢指标的差异。结果2组治疗6个月有效率分别为90.57%和83.02%,差异无统计学意义(P>0.05),优良率分别为73.58%和52.83%,差异有统计学意义(P<0.05)。2组治疗1、3、6个月时Cobb角和ODI均明显低于治疗前(P<0.05),且观察组治疗6个月时ODI低于对照组,差异有统计学意义(P<0.05)。2组治疗3、6个月时骨密度均明显高于治疗前(P<0.05),且观察组治疗6个月时骨密度高于对照组,差异有统计学意义(P<0.05)。与治疗前相比,2组治疗1、3、6个月时BALP和PINP水平明显升高(P<0.05),β-CTX水平均明显降低(P<0.05),且观察组治疗1、3、6个月时BALP和PINP水平均高于对照组,差异有统计学意义(P<0.05)。结论OVCF病人PKP术后应用骨化三醇进行治疗具有良好效果,有利于改善骨代谢并增加骨密度,对促进骨折愈合、改善脊柱功能和提升日常生活能力具有积极作用。

氯球嫁接L-脯氨酸绿色催化合成香豆素-3-羧酸酯

将L-脯氨酸嫁接在树脂氯球上,催化水杨醛及其衍生物和丙二酸酯直接合成香豆素-3-羧酸酯类物质,反应具有选择性强、产率高、成本低、三废少、后处理简单、催化剂可以多次重复使用等优点,符合绿色催化的特性。实验表明:反应在100℃下,醛和酯的摩尔比为1:1.2,催化剂的用量1 g,10 mL DMF中反应5h,反应的选择性≥98%,产率高达92%;催化剂循环使用6次反应的产率仍在85%以上。在此优化的反应条件下,高效合成了一系列其他香豆素-3-羧酸酯类物质,产品的结构和纯度通过了NMR、IR和熔点等手段进行了鉴定。

有机化学教学实验的改进与拓展设计

“香豆素-3-羧酸的制备”是一个经典的有机化学教学实验。一般采用哌啶催化Knoevenagel反应合成香豆素-3-羧酸乙酯,但哌啶为第二类易制毒试剂,属于管制药品,气味大、腐蚀性强。该实验缺少产物性质应用的相关实验,仅涉及有机物的制备和纯化。因此,对该实验进行了改进与拓展设计:采用功能化离子液体催化Knoevenagel反应,实现了香豆素-3-羧酸乙酯的绿色合成;通过香豆素-3-羧酸与Eu3+配位后荧光的“开-关”实验丰富了实验教学内容。实验现象明显,让学生更好地理解了金属离子与配体之间的络合反应,实现了“有机合成”与“性质应用”相统一。该设计实验加强了学科的交叉融合,激发了学生的学习兴趣,培养了学生的绿色化学理念和创新性思维,受到了学生的一致好评。

烷基水杨酸盐清净剂合成工艺研究进展

近年来,随着节约能源和保护环境的要求逐渐提高,发动机设计日益向小型化,大功率和高速度方向发展,因此对内燃机油的高温清净性能提出了越来越苛刻的要求,低硫低磷及低灰分型内燃机油将是未来发展的方向。烷基水杨酸盐具有优异的清净作用及酸中和性能,且具备一定的抗氧化和抗腐蚀能力,是内燃机油的主要添加剂之一,可满足内燃机油低硫低磷及低灰分的要求。对烷基水杨酸盐的传统及改进的合成工艺进行了综述。传统合成工艺严重制约了烷基水杨酸盐的应用和发展,探索新的合成工艺是烷基水杨酸盐发展的主要方向。

小麦叶片和冠层尺度气体交换模型关键参数的季节变化特征

本文从叶片和冠层尺度入手,采用手持式光合仪和涡动相关法,分析确定C3作物春小麦和冬小麦气体交换模型关键参数随季节变化的特征。结果表明:春小麦叶片尺度最大羧化速率和最大电子传递速率在生育末期快速减小,其他阶段差异不显著,但二者之比随发育期变化相对稳定,均值为2.2;春小麦生长季叶片气孔导度模型斜率在9~11间变动,均值为9.7。冬小麦冠层尺度最大羧化速率和最大电子传递速率随发育期呈抛物线变化,但二者之比相对稳定,均值为1.43;冬小麦冠层导度模型斜率在不同年份不同季节变化无明显规律,整个生育期围绕均值12波动。本研究论证了表征作物光合能力的参数随生育期变化以及气孔导度模型斜率相对稳定的特征。可为陆气相互作用过程分析以及生态系统碳—水循环模拟提供参数化依据。

一例U-Ag杂金属半刚性羧酸配体配合物的制备及性质研究

为了深入研究锕系元素的配位行为,基于半刚性羧酸配体3-(羧基甲氧基)苯甲酸(H_(2)L),合成了一个三维结构的U-Ag杂金属配合物[(L)(HL)Ag(UO_(2))](简称UAgL)。通过X-射线单晶衍射、红外光谱、紫外光谱及X-射线粉末衍射对其晶体结构进行了表征,结果显示,配合物UAgL中铀原子处于稍变形的五角双锥配位环境中,银原子则处于五配位的四方锥配位环境中。铀酰离子中的氧原子参与配位且处于轴向位置,完全脱质子的配体L和部分脱质子的配体HL则采取两种配位模式将铀中心与银中心连接成二维层状结构,层状结构之间又通过铀酰氧原子连接成三维的网络结构。进一步探讨了配合物UAgL的热稳定性和在室温下的固态荧光性质,认为其可作为潜在的光致发光材料。