Effects of 1-methylcyclopropene on skin greasiness and quality of'Yuluxiang'pear during storage at 20℃

During storage at 20℃,specific pear cultivars may exhibit a greasy texture and decline in quality due to fruit senescence.Among these varieties,‘Yuluxiang’is particularly susceptible to peel greasiness,resulting in significant economic losses.Therefore,there is an urgent need for a preservative that can effectively inhibit the development of greasiness.Previous studies have demonstrated the efficacy of 1-methylcyclopropene(1-MCP)in extending the storage period of fruits.We hypothesize that it may also influence the occurrence of postharvest peel greasiness in the‘Yuluxiang’pears.In this study,we treated‘Yuluxiang’pears with 1-MCP.We stored them at 20℃while analyzing the composition and morphology of the surface waxes,recording enzyme activities related to wax synthesis,and measuring indicators associated with fruit storage quality and physiological characteristics.The results demonstrate that prolonged storage at 20℃leads to a rapid increase in skin greasiness,consistent with the observed elevations in L^(*),greasiness score,and the content of total wax and greasy wax components.Moreover,there were indications that cuticular waxes underwent melting,resulting in the formation of an amorphous structure.In comparison to controls,the application of 1-MCP significantly inhibited increments in L^(*) values as well as grease scores while also reducing accumulation rates for oily waxes throughout most stages over its shelf period,additionally delaying transitions from flaky-wax structures towards their amorphous counterparts.During the initial 7 d of storage,several enzymes involved in the biosynthesis and metabolism of greasy wax components,including lipoxygenase(LOX),phospholipase D(PLD),andβ-ketoacyl-CoA synthase(KCS),exhibited an increase followed by a subsequent decline.The activity of LOX during early shelf life(0–7 d)and the KCS activity during middle to late shelf life(14–21 d)were significantly suppressed by 1-MCP.Additionally,1-MCP effectively maintained firmness,total soluble solid(TSS)and titratable acid(TA)contents,peroxidase(POD),and phenylalanine ammonia-lyase(PAL)activities while inhibiting vitamin C degradation and weight loss.Furthermore,it restrained polyphenol oxidase(PPO)activity,ethylene production,and respiration rate increase.These findings demonstrate that 1-MCP not only delays the onset of peel greasiness but also preserves the overall storage quality of‘Yuluxiang’pear at a temperature of 20℃.This study presents a novel approach for developing new preservatives to inhibit pear fruit peel greasiness and provides a theoretical foundation for further research on pear fruit preservation.

Effects of 1-methylcyclopropene treatment on the quality of red‘Fuji’apples fruit during short-term storage

Objectives:The aim of this study is to determine the mechanism through which 1-methylcyclopropene(1-MCP)affects the quality of red'Fuji'apples,which were stored for a short duration.Materials and Methods:Red‘Fuji’apples were treated with 1-MCP(1.0μl/L),stored at 25℃for0,12,24,48,72,and 96 h,and ethylene pro-duction was measured.An integrated metabolomic and transcriptomic analysis was performed on apples stored for 24 h.Results:The release of ethylene was significantly delayed from red‘Fuji’apples subjected to 1-MCP treatment.By performing an integrated transcriptome and metabolome analyses,we identified 117 differentially expressed genes(DEGs)and 44 differentially accumulated metabol-ites(DAMs).By performing functional enrichment analysis,we found that DEGs were involved in the following pathways;carbon metabolism(LPD2,gpmA,LTA2,ACC,PSAT1,MdCAS2),phytohormone signal transduction(EBF 7),amino acid metabolism(MdACS-1),fatty acid metab-olism(LOX1.5,KCS4,KAST),energy metabolism(Lhcb1,Lhcb6,PsbY,GPDHC1,PUMP5I,metabolic pathways(TRE1,HEXO1)and cell wall metabolism(CSLG2).Thus,these DEGs were involved in the ripening of fruits,and they controlled the quality of fruits at the post-harvest stage.The metabolites were enriched with DAMs.These were found to be individually involved in the metabolic pathway,secondary metabolite bio-synthesis,phenylpropanoid biosynthesis,flavonoids,and flavonol synthesis.Conclusions:The results indicate that 1-MCP inhibits the biosynthesis of ethylene and suppresses energy metabolism.Moreover,it also downregulates metabolic pathways and the enzymatic genes related to fruit quality.Therefore,1-MCP delays the ripening of fruits at the post-harvest stage.This study helps us understand how 1-MCP treatment affects the ripening and quality of fruits.

Bonding enhancement of cold rolling TA1 P-Ti/AA6061 composite plates via surface oxidation treatment

TA1 P-Ti/AA6061 composite plate was produced by oxidizing the surface of the titanium plate and adopting a cold roll bonding process.The results revealed that the oxide film(Ti6O)prepared on the surface of TA1 pure titanium was easy to crack during the cold roll bonding,thereby promoting the formation of an effective mechanical interlock at the interface,which can effectively reduce the minimum reduction rate of the composite plates produced by cold rolling of titanium and aluminium plates.Moreover,the composite plate subjected to oxidation treatment exhibited high shear strength,particularly at a 43%reduction rate,achieving a commendable value of 117 MPa.Based on oxidation treatment and different reduction rates,the annealed composite plates at temperatures of 400,450,and 500°C displayed favorable resistance to interface delamination,highlighting their remarkable strength-plasticity compatibility as evidenced by a maximum elongation of 31.845%.

Postharvest Application of 1-Methylcyclopropene Maintains Quality and Extends the Shelf-Life of Zizania latifolia during Storage at 25˚C

The effects of 1-methylcyclopropene (1-MCP) on postharvest quality of Zizania latifolia during storage at 25˚C were investigated. The results pointed out that a postharvest application of 1-MCP maintained the good visual appearance of fresh Z. latifolia, inhibited browning, mildew and weight loss at the bottom of Z. latifolia, and there is no significant changes on L, a*, b* and ΔE during the whole storage period. In addition, 1-MCP treatment inhibited the respiratory intensity of Z. latifolia during the first three days of storage, but it was significantly higher than that of the control on the sixth day of storage. Compared with the control, 1-MCP treatment maintained relatively high SOD, CAT, APX activities and low PAL, POD, PLD, lipase and LOX activities, delayed the decline of AsA content, reduced the accumulation of O2-, H2O2 and MDA, and ultimately maintained the integrity of cell structure and delayed the senescence of Z. latifolia. In addition, positive effects of 1-MCP on maintaining the cell structure integrity were observed in this investigation throughout the storage period at 25˚C.

Paper-containing 1-methylcyclopropene treatment suppresses fruit decay of fresh Anxi persimmons by enhancing disease resistance

Objectives:The purpose of this work was to evaluate the potential application of papers containing 1-methylcyclopropene(1-MCP)postharvest treatment for suppressing fruit decay of fresh Anxi persimmons and its possible mechanism.Materials and methods:Anxi persimmon fruit were treated with papers containing 1-MCP at the dosage of 1.35μL/L and stored at(25±1)℃and 85 per cent relative humidity for 35 days.During storage,the fruit decay rate and lignin content were evaluated,and the content of total phenolics,the activities of phenylalanine ammonia lyase(PAL),polyphenol oxidase(PPO),peroxidase(POD),chitinase(CHI),and p-1,3-glucanase(GLU)were determined by spectrophotometry.Results:The 1-MCP-treated persimmons displayed a lower fruit decay rate,but higher contents of lignin and total phenolics,higher activities of PAL,PPO,POD,CHI,and GLU.Conclusions:The treatment with 1-MCP could inhibit the fruit decay of postharvest Anxi persimmons,which might be because 1-MCP enhanced fruit disease resistance by increasing the activities of disease resistance-associated enzymes and retaining higher contents of disease resistance-related substances in postharvest fresh Anxi persimmons.These findings indicate that papers containing 1-MCP at the dosage of 1.35μL/L have potential application in suppressing fruit decay and extending storage life of postharvest fresh Anxi persimmons.

Effect of Internal Ethylene and 1-Methylcyclopropene on Ethylene Metabolism and Membrane Lipid Peroxidation in Papaya Fruit

[Objective] This study was conducted to evaluate the effect of 1-methylcy- clopropene （1-MCP） on fruit firmness, and the activity of the enzymes involved in ethylene metabolism and membrane lipid peroxidation. [Method] The nearly ripe fruits of the papaya cultivar Risheng were randomly assigned to one of four groups. Two groups were treated under hypobaric and hypoxic （HH） atmosphere condition for six hours, and immediately soaked in deionized water （HH alone）, or fumigated with 2.0 mg/L 1-MCP （HH＋I-MCP） for 24 h. The other two groups untreated under HH condition were also soaked in deionized water （negative control）, or fumigated with 2.0 mg/L 1-MCP （1-MCP alone） for 24 h. After that, the fruits of all the four treatments were stored at room temperature （23＋1） ℃. Cell membrane permeability, fruit firmness, respiration rate, ethylene release rate, SOD activity, POD activity, CAT activity, MAD content and LOX activity were measured once every three days during storage. [Result] Treatment with 1-MCP delayed the occurrence of the peaks of respiration rate and ethylene release rate, significantly reduced the accumulation of malondialdehyde （MDA）, and inhibited the decrease in papaya fruit firmness. Compared with the control, 1-MCP treatment significantly increased the SOD （su- peroxide dismutase）, POD （peroxidase） and CAT （catalase） activity, reduced the ac- tivity of lipoxygenase （LOX）, a product of lipid peroxidatlon in membranes, and in- hibited ethylene biosynthesis, thus delaying the aging process and prolonging the storage life of papaya fruits. [Conclusion] The results will provide a theoretical basis for analvzina the key factors controllinq postharvest maturity and aging of papaya fruits.

安罗替尼联合程序性死亡蛋白-1抑制剂治疗晚期非小细胞肺癌患者的临床疗效

【目的】探讨安罗替尼联合程序性死亡蛋白-1(programmed death-1,PD-1)抑制剂联合治疗晚期非小细胞肺癌(NSCLC)患者的疗效。【方法】回顾性分析90例NSCLC患者的临床资料,按照治疗方法不同分为对照组(n=30,采用安罗替尼治疗)和观察组(n=60,接受安罗替尼联合PD-1抑制剂治疗)。比较两组患者的近期疗效、生存情况和药物安全性。【结果】观察组治疗后客观缓解率(ORR)为11.67%(7/60),疾病控制率(DCR)为60.00%(36/60),分别高于对照组的6.67%(2/30)和33.33%(10/30),且差异有统计学意义(P<0.05)。观察组患者的中位无进展生存期(PFS)为10个月,中位总生存期(OS)为13个月,高于对照组患者(中位PFS为7个月,中位OS为11个月),且差异有统计学意义(P<0.05)。两组各项不良反应发生率比较,差异均无统计学意义(P>0.05)。【结论】安罗替尼联合PD-1抑制剂治疗晚期NSCLC患者,可有效提高患者的近期疗效,同时延长患者的生存期。

Mechanism and Kinetics of Thermal Dissociation of Inclusion Complex of β-Cyclodextrin and 1-Methylcyclopropene

The inclusion-complex of CD-MCP （β-cyclodextrin （β-CD） including 1-methylcyclopropene （1-MCP）） was prepared and characterized. Basing on programmed-heating procedure and weight-temperature analysis, as well as the application of Satava-Sestak＇s, Ozawa＇s and Kissinger＇s methods, the mechanism and kinetics of thermal dissociation of this inclusion complex were studied. An additional mass loss is found at 170-180℃. The mechanism of thermal dissociation of CD-MCP is dominated by a one-dimensional random nucleation and subsequent growth process （A2/3）. The activation energy Es and the pre-exponential factor AS for the process are 102.14 kJ/mol and 3.63×10^10s^-1, respectively. This ES value shows that there is no strong chemical intere, ctions between β-CD and 1-MC;P,

Preharvest application of 1-methylcyclopropene and Ethephon altered cuticular wax biosynthesis and fruit quality of apples at harvest and during cold storage

To investigate the roles of Harvista(a sprayable 1-methylcyclopropene,1-MCP,available component is 150 g·hm^(-2))and Ethephon(1 mL·L^(-1))applied at preharvest in apple(Malus domestica Borkh.'Golden Delicious')fruit cuticular wax biosynthesis,the expression of genes related to fruit cuticular wax biosynthesis and ethylene biosynthesis and signaling,ethylene production rate,respiration rate,wax constituents and structure,and fruit quality were determined at harvest and during cold storage.The results showed that 1-MCP inhibited the expression levels of ethylene biosynthesis and signaling-related genes,decreased fruit ethylene production,and inhibited the expression of Md LACS1,Md CER6,Md CER4 and Md WSD1,which resulted in decreases in alcohols,acids,and esters content in fruit cuticular wax.1-MCP also reduced fruit dropping rate from 17.17%to 12%;maintained fruit firmness,soluble solids,titratable acidity during cold storage;showed about as one fifth in the total length and one third in the widest width of wax crack as that in control at harvest.In contrast,Ethephon produced the opposite effects.In conclusion,1-MCP inhibited fruit ethylene biosynthesis and signaling,and influenced fruit cuticular wax biosynthesis.Thus,the fruit cuticular wax constituents and structure was altered,and the fruit quality were maintained at harvest and during cold storage.The results provide a new technology for improving apple fruit harvest and postharvest quality by preharvest application of sprayable 1-MCP.

Current progress in application of 1-Methylcyclopropene to improve postharvest quality of cut flowers

Floral senescence or petal abscission that determine cut flower quality and longevity are primarily caused by the regulation of endogenous ethylene and perception of endogenous and exogenous ethylene in floral organs(such as the petals and gynoecium),in ethylene-sensitive species.Several attempts have been made to prolong flower quality and longevity using silver ions and other chemicals that inhibit ethylene production and perception in floral organs.Among the available compounds,1-methylcyclopropene(1-MCP)has been increasingly used as ethylene-action/perception inhibitor because of its ability to inhibit ethylene action/perception and it is environmentally safe.Although 1-MCP has been used in several cut flower crops for about 25 years,there has been no review yet that critically emphasizes the benefits or difficulties of using this compound for the prolongation of cut flower quality and longevity.Here,we outline the role of 1-MCP in inhibiting ethylene action/perception and petal senescence in cut flowers through the blocking of receptor binding sites,and we discuss how various factors affecting efficacy of 1-MCP(such as concentration,treatment time and temperature,genotype,and flower stage)are involved in the achievement of flower longevity.Moreover,we highlight the advantages of applying nonvolatile and liquid 1-MCP formulation types,as opposed to using the conventional 1-MCP treatment(powder formulation type).We expect that this review will provide useful information for the future utilization of 1-MCP for the maintenance of cut flower longevity.

Roles of fibroblast growth factors in the treatment of diabetes

Diabetes affects about 422 million people worldwide,causing 1.5 million deaths each year.However,the incidence of diabetes is increasing,including several types of diabetes.Type 1 diabetes(5%-10%of diabetic cases)and type 2 diabetes(90%-95%of diabetic cases)are the main types of diabetes in the clinic.Accumulating evidence shows that the fibroblast growth factor(FGF)family plays important roles in many metabolic disorders,including type 1 and type 2 diabetes.FGF consists of 23 family members(FGF-1-23)in humans.Here,we review current findings of FGFs in the treatment of diabetes and management of diabetic complications.Some FGFs(e.g.,FGF-15,FGF-19,and FGF-21)have been broadly investigated in preclinical studies for the diagnosis and treatment of diabetes,and their therapeutic roles in diabetes are currently under investigation in clinical trials.Overall,the roles of FGFs in diabetes and diabetic complications are involved in numerous processes.First,FGF intervention can prevent high-fat diet-induced obesity and insulin resistance and reduce the levels of fasting blood glucose and triglycerides by regulating lipolysis in adipose tissues and hepatic glucose production.Second,modulation of FGF expression can inhibit renal and cardiac fibrosis by regulating the expression of extracellular matrix components,promote diabetic wound healing process and bone repair,and inhibit cancer cell proliferation and migration.Finally,FGFs can regulate the activation of glucoseexcited neurons and the expression of thermogenic genes.

儿童神经纤维瘤病1型颅内肿瘤性病变的治疗进展

神经纤维瘤病1型(neurofibromatosis 1,NF1)好发于儿童,是神经系统最常见的常染色体显性遗传病之一,是基因缺陷使神经嵴细胞发育异常导致的多系统损害。NF1的外显率几乎是100%,主要临床特征为皮肤牛奶咖啡斑和周围神经多发神经纤维瘤。NF1在颅内能引起肿瘤性病变,后者按照病理学依据可分为低级别肿瘤、高级别肿瘤和类似肿瘤病变。合并NF1的颅内肿瘤多为低级别肿瘤,视路胶质瘤最为多见,其次是脑干胶质瘤,其余部位和类型的肿瘤也有所发生;高级别肿瘤并不常见。而类似肿瘤病变即不明明亮物体虽不是肿瘤,但却是NF1儿童最常见的具有部分肿瘤性质的颅内异常病变。这些肿瘤性病变可通过观察、手术、化学治疗、放射治疗、靶向治疗等方式处理,不同病变的最佳处理方式不同,其预后也有所不同。目前针对儿童NF1颅内肿瘤性病变的治疗方式还有所争议。该文就此种病变的特点和治疗进展进行阐述,旨在提高大众对NF1肿瘤性病变的认知水平,提供针对性的诊疗方案,推进NF1患者完善神经外科治疗。

程序性死亡受体1单抗诱发重度免疫性血小板减少(附3例报告)

目的分析程序性死亡受体1(PD-1)单抗诱发重度免疫性血小板减少(SIT)的诊断与治疗。方法选取浙江省舟山市普陀区人民医院2020年3月至2022年10月因PD-1单抗治疗导致SIT患者3例,分析其诊疗过程和病情转归。结果3例患者术后病理均确诊恶性肿瘤给予PD-1单抗后诱发SIT,其中1例患者死亡,2例患者经治疗后好转。结论PD-1诱发SIT多发生于12周以后,可结合患者用药史、血小板抗体、骨髓检查明确临床诊断。在治疗上,激素有序减量,血小板生成素、血小板受体激动剂等联合治疗可促进患者恢复。此外,必要时可使用CD20单抗治疗以拮抗血小板抗体。

猫过敏原Fel d 1研究进展

全球有相当一部分人群因对猫过敏而受到影响,患者症状小到鼻炎,大到哮喘,甚至呼吸障碍,对过敏患者的生活造成严重影响。Fel d 1是目前公认的主要猫过敏原,是一种分泌型球蛋白,主要产生于猫的皮脂腺和唾液腺,在猫梳理毛发的过程中分布到猫毛上,并最终散播到空气中。为解决人类对猫过敏这一难题,相关研究人员尝试从多条途径减少Fel d 1的分泌或控制其传播,以达到缓解或消除猫过敏患者的过敏反应,如通过清洁猫毛、清洁室内环境、培育低过敏性猫、为猫注射疫苗等方法来实现。本文就猫过敏原的研究进展和对猫过敏的管理控制以及治疗措施进行综述。

1型糖尿病诱发肌少症的研究进展

1型糖尿病的肌少症患病率明显高于2型糖尿病及非糖尿病患者,尽早对1型糖尿病患者进行肌少症的筛查、诊断和干预治疗对于提高这些患者的生活质量具有重大意义。1型糖尿病患者肌少症的发生可能与胰岛素样生长因子-1减少、炎性因子激活、线粒体功能障碍、晚期糖基化终末产物蓄积等导致骨骼肌功能下降密切相关。目前,1型糖尿病诱发肌少症的发生发展机制并不完全明确,相关新药治疗缺乏数据支持,进一步的深入研究可能给1型糖尿病患者防治肌少症提供新的方向。

急性大血管闭塞性卒中患者中omentin-1、AQP4、VILIP-1与急诊血管内治疗后血管再通的关系

目的探讨急性大血管闭塞性卒中(ALVOS)患者中网膜素-1(omentin-1)、水通道蛋白4(AQP4)、视锥蛋白样蛋白-1(VILIP-1)与急诊血管内治疗后血管再通的关系及联合预测效能。方法选取110例行急诊血管内治疗的ALVOS患者,根据术后血管是否再通分为未再通组(23例)和再通组(87例),比较2组的临床资料和omentin-1、AQP4、VILIP-1水平。采用LASSO回归初筛术后血管再通的特征变量,寻找可使模型性能优良且影响因素最少的变量。采用logistic回归分析术后血管再通的影响因素。应用R语言绘制列线图预测术后血管再通,应用受试者操作特征(ROC)曲线和校准曲线评价、验证列线图的预测效能和校准度。结果未再通组高血压患者占比、术前美国国立卫生研究院卒中量表(NIHSS)评分、急诊血糖、AQP4和VILIP-1水平高于再通组,发病至血管内治疗时间长于再通组,术前Alberta卒中项目早期CT评分(ASPECTS)、静脉溶栓患者占比、血小板、omentin-1水平低于再通组(P<0.05)。术前ASPECTS、omentin-1水平是术后血管再通的相关独立保护因素,发病至血管内治疗时间、术前NIHSS评分、AQP4和VILIP-1水平是术后血管再通的相关独立危险因素(P<0.05)。运用R语言对logistic回归进行列线图可视化分析,该列线图预测术后血管再通的一致性指数为0.994,呈现出良好的区分度;列线图的ROC曲线显示,列线图预测术后血管再通的AUC为0.994,预测灵敏度为98.90%,特异度为95.70%,校准度为0.975,与实际观测结果曲线贴合度良好。结论omentin-1、AQP4、VILIP-1水平为ALVOS患者急诊血管内治疗后血管再通的重要影响因素,临床可通过监测其水平进行早期预测,采取针对性治疗,改善血管再通情况。

基于转录组学分析1-MCP与EBR联合处理对鲜黄花菜采后衰老的影响

利用不同剂量1-甲基环丙烯(1-methylcyclopropene,1-MCP)、2,4-表油菜素内酯(2,4-epibrassionolide,EBR)及其联合处理鲜黄花菜并进行为期15 d的贮藏实验(贮藏温度-1~1℃),通过测定理化指标并进行转录组学分析,研究1-MCP与EBR及其联合处理对鲜黄花菜采后衰老的影响。结果表明,采后使用1μL/L 1-MCP与1 mg/L EBR联合处理能够比单独处理更有效地延缓鲜黄花菜的黄化、伸长、软化、开散、质量损失、叶绿素降解等不良变化,从而极大地维持黄花菜花蕾的贮藏品质。转录组学分析表明,1-MCP与EBR联合处理调控了黄花菜衰老进程相关基因的转录水平,显著抑制了乙烯的生物合成和信号转导途径相关基因的转录,激活了油菜素内酯的生物合成和信号转导途径相关基因的转录,从而改变了黄花菜体内衰老类和生长类植物激素的代谢平衡。1-MCP与EBR联合处理抑制了叶绿素降解途径相关基因转录,有利于保持鲜黄花菜品质;联合处理也抑制了与衰老密切相关的E3泛素连接酶基因的转录,从而延缓细胞中蛋白质降解,推迟鲜黄花菜采后衰老的生理进程。研究结果可为延缓鲜黄花菜花蕾的采后衰老和保持贮藏品质提供理论依据和实践参考。

短期微流水处理对池塘养殖杂交鲌“先锋1号”肌肉品质的影响

以池塘养殖杂交鲌“先锋1号”为对象,采用短期微流水处理,研究处理时间(0、4、8和12d)对杂交鲌“先锋1号”色度、肌纤维直径、肌肉质构特性、常规营养成分、氨基酸和脂肪酸含量的影响,以评价短时间微流水处理对杂交鲌“先锋1号”品质的提升作用。结果显示,微流水条件下,8 d和12 d皮的黄度值(b^(*))显著升高,各实验组肌肉的红度值(a^(*))显著降低(P<0.05,下同)。处理8 d时,肌纤维密度、肌肉硬度、咀嚼性和弹性显著提升,分别较对照组提升了70.96%、92.04%、198.99%和35.71%。随着处理时间的延长,粗蛋白和粗脂肪含量显著降低,灰分在处理过程中无显著差异(P>0.05,下同);杂交鲌“先锋1号”在处理4d时的鲜味氨基酸总量(DAA)显著高于8d和12d;氨基酸总量(TAA)和必需氨基酸总量(EAA)变化不显著,各组必需氨基酸指数(EAAI)分别为77.33%、74.91%、76.56%和76.75%。第8天时,肌肉中顺-15-二十四碳一烯酸(C24:1)、花生三烯酸(C20:3n6)和花生四烯酸(C20:4n6)含量分别为6.85、41.05和53.84 mg/100 g显著高于其他各组,而α-亚麻酸含量,单不饱和脂肪酸总量和n-6多不饱和脂肪酸(n-6PUFAs)总量分别为48.05、1336.43和524.43 mg/100 g显著高于4 d和12 d。研究表明,短期微流水处理8 d时,在保证肌肉营养品质的同时,可有效改善其体色和肌肉颜色,增加肌肉口感,为池塘养殖淡水产品品质提升提供新的思路。

Effect of mesopore spatial distribution of HZSM-5 catalyst on zinc state and product distribution in 1-hexene aromatization

1-hexene aromatization is a promising technology to convert excess olefin in fluid catalytic cracking(FCC)gasoline to high-value benzene(B),toluene(T),and xylene.Besides,the increasing market demand of xylene has put forward higher requirements for new generation of catalyst.For increasing xylene yield in 1-hexene aromatization,the effect of mesopore structure and spatial distribution on product distribution and Zn loading was studied.Catalysts with different mesopore spatial distribution were prepared by post-treatment of parent HZSM-5 zeolite,including NaOH treatment,tetra-propylammonium hydroxide(TPAOH)treatment,and recrystallization.It was found the evenly distributed mesopore mainly prolongs the catalyst lifetime by enhancing diffusion properties but reduces the aromatics selectivity,as a result of damage of micropores close to the catalyst surface.While the selectivity of high-value xylene can be highly promoted when the mesopore is mainly distributed interior the catalyst.Besides,the state of loaded Zn was also affected by mesopores spatial distribution.On the optimized catalyst,the xylene selectivity was enhanced by 12.4%compared with conventional Zn-loaded parent HZSM-5 catalyst at conversion over 99%.It was attributed to the synergy effect of mesopores spatial distribution and optimized acid properties.This work reveals the role of mesopores in different spatial positions of 1-hexene aromatization catalysts in the reaction process and the influence on metal distribution,as well as their synergistic effect two on the improvement of xylene selectivity,which can improve our understanding of catalyst pore structure and be helpful for the rational design of high-efficient catalyst.

High Temperature and the Ethylene Antagonist 1-Methylcyclopropene Alter Ethylene Evolution Patterns,Antioxidant Responses,and Boll Growth in Gossypium hirsutum

The cotton (Gossypium hirsutum L.) crop experiences high temperatures during flowering and boll development, but information regarding the impact of ethylene inhibition and high temperature on early boll development is limited. The objective of this study was to determine the effects of high temperature and the anti-ethylene compound 1-methylcy-cloprone (1-MCP) on G. hirsutum boll development. Treatments consisted of temperature regime (38/20?C and 30/ 20?C), 1-MCP treatment, and days past anthesis (DPA). High temperature decreased ethylene synthesis by 61% at 2 DPA, and 1-MCP caused a 40% decrease in ethylene production at 1 DPA. Glutathione reductase activity increased under high temperature, whereas superoxide dismutase activity (SOD) and membrane peroxidation (malondialdehyde content) remained unchanged. 1-MCP treatment did not affect GR activity in developing bolls. High temperature and 1-MCP treatment increased the weight of cotton bolls collected 8 DPA with an increase of 0.7 and 1 g, respectively. We propose that increased GR activity in bolls exposed to high temperature may mitigate oxidative damage. Additionally, we conclude that ethylene inhibition (either high temperature or 1-MCP-induced) immediately after flowering (1 or 2 DPA) could potentially have positive impacts on early boll growth.