Mitigating ethyl carbamate production in Chinese rice wine:Role of raspberry extract

This study investigated the use of raspberry extract(RBE) for mitigating ethyl carbamate(EC) accumulation in Chinese rice wine(Huangjiu), a traditional fermented beverage. It focused on the addition of RBE to the fermentation mash and its effects on EC levels. The results showed a significant reduction in EC production that could be attributed to RBE's role in altering urea and citrulline catabolism and inhibiting arginine metabolism, thus preventing EC precursors from reacting with ethanol. Additionally, RBE enhanced the rice wine's flavor profile, as shown by volatile component and amino acid analysis. This study also explored RBE's impact on the metabolism of arginine by Saccharomyces cerevisiae in a simulated fermentation environment, and found increased arginine, reduced urea and citrulline levels, altered enzyme activities, and gene expression changes in the arginine metabolism and transport pathways. In conclusion, the results clearly demonstrated RBE's efficacy in reducing the EC content in Chinese rice wine, offering valuable insights for EC reduction strategies.

Ethyl acetate fraction of Sargassum pallidum extract attenuates particulate matter-induced oxidative stress and inflammation in keratinocytes and zebrafish

Objective:To evaluate the effect of the ethyl acetate fraction derived from Sargassum pallidum extract against particulate matter(PM)-induced oxidative stress and inflammation in HaCaT cells and zebrafish.Methods:HaCaT cells and zebrafish were used to evaluate the protective effects of the ethyl acetate fraction of Sargassum pallidum extract against PM-induced oxidative stress and inflammation.The production of nitric oxide(NO),intracellular ROS,prostaglandin E_(2)(PGE_(2)),and pro-inflammatory cytokines,and the expression levels of COX-2,iNOS,and NF-κB were evaluated in PM-induced HaCaT cells.Furthermore,the levels of ROS,NO,and lipid peroxidation were assessed in the PM-exposed zebrafish model.Results:The ethyl acetate fraction of Sargassum pallidum extract significantly decreased the production of NO,intracellular ROS,and PGE_(2) in PM-induced HaCaT cells.In addition,the fraction markedly suppressed the levels of pro-inflammatory cytokines and inhibited the expression levels of COX-2,iNOS,and NF-κB.Furthermore,it displayed remarkable protective effects against PM-induced inflammatory response and oxidative stress,represented by the reduction of NO,ROS,and lipid peroxidation in zebrafish.Conclusions:The ethyl acetate fraction of Sargassum pallidum extract exhibits a protective effect against PM-induced oxidative stress and inflammation both in vitro and in vivo and has the potential as a candidate for the development of pharmaceutical and cosmeceutical products.

Tailoring Ni based catalysts by indium for the dehydrogenative coupling of ethanol into ethyl acetate

Exploring stable and robust catalysts to replace the current toxic CuCr based catalysts for dehydrogenative coupling of ethanol to ethyl acetate is a challenging but promising task.Herein,novel NiIn based catalysts were developed by tailoring Ni catalysts with Indium(In)for this reaction.Over the optimal Ni0.1Zn0.7Al0.3InOx catalyst,the ethyl acetate selectivity reached 90.1%at 46.2%ethanol conversion under the conditions of 548 K and a weight hourly space velocity of 1.9 h^(-1)in the 370 h time on stream.Moreover,the ethyl acetate productivity surpassed 1.1 g_(ethyl acetate)g_(catalyst)^(-1)h^(-1),,one of the best performance in current works.According to catalyst characterizations and conditional experiments,the active sites for dehydrogenative coupling of ethanol to ethyl acetate were proved to be Ni4In alloys.The presence of In tailored the chemical properties of Ni,and subsequently inhibited the C-C cracking and/or condensation reactions during ethanol conversions.Over Ni4In alloy sites,ethanol was dehydrogenated into acetaldehyde,and then transformed into acetyl species with the removal of H atoms.Finally,the coupling between acetyl species and surface-abundant ethoxyde species into ethyl acetate was achieved,affording a high ethyl acetate selectivity and catalyst stability.

Syntheses,structures,and properties of three coordination polymers based on 5⁃ethylpyridine⁃2,3⁃dicarboxylic acid and N⁃containing ligands

Three coordination polymers[Mn(epda)(2,2'⁃bipy)(H_(2)O)](1),[Mn(epda)(phen)](2),and[Co_(2)(epda)2(bpe)2(H_(2)O)_(4)]·5H_(2)O(3)(H2epda=5⁃ethyl⁃pyridine⁃2,3⁃dicarboxylic acid,2,2'⁃bipy=2,2'⁃bipyridine,phen=phenanthroline,bpe=1,2⁃bis(4⁃pyridyl)ethylene)were synthesized by solvothermal reactions and characterized by single⁃crystal X⁃ray diffraction,thermogravimetric analyses,IR spectroscopy and elemental analysis.1 displays a 1D chain struc⁃ture,and these chains are joined by O-H…O hydrogen bonding andπ⁃πstacking interactions to generate a 2D layer structure.2 displays a 2D layer structure,and adjacent layers are generated 3D architecture throughπ⁃πstacking interactions.3 displays a 1D chain structure,and adjacent chains are generated double layer structure through O-H…O hydrogen bonding.The fluorescent properties of 1 and 3 indicate that they can potentially be used as a luminescent sensor.1 was highly selective and sensitive towards o⁃nitrophenol through different detection mechanisms,however,3 was highly selective and sensitive towards 2,4,6⁃trinitrophenol.In addition,the magnetic behavior of 2 has also been investigated.CCDC:2172533,1,2355773,2,2355774,3.

高电压正极材料LiFe_(0.06)Ni_(0.94)PO_(4)/C的制备及其性能研究

磷酸镍锂(LiNiPO_(4))是一种具有5.1 V高电压平台的橄榄石类锂离子电池正极材料,由于较低的电导率和实际放电比容量限制了其实际应用。为了制备纯相LiNiPO_(4),考察了不同摩尔比表面活性剂油胺对LiNiPO_(4)的影响,油胺添加摩尔比[n(油胺)∶n(金属)]为10∶1制备的材料结晶度最佳,经过煅烧工艺参数优化成功获得纯相LiNiPO_(4)。为了改善LiNiPO_(4)的电化学性能,首次采用乙基纤维素为碳源制备的掺有Fe摩尔分数为6%的LiFe_(0.06)Ni_(0.94)PO_(4)/C并将其电化学性能与纯相LiNiPO_(4)进行比较,结果表明,采用乙基纤维素制备的LiFe_(0.06)Ni_(0.94)PO_(4)/C具有更大的初始放电比容量、更小的电荷转移电阻,其中10%乙基纤维素添加量的样品电化学性能最佳。

乙酰丙酸乙酯复配燃料理化特性研究

对不同比例乙酰丙酸乙酯与0#石化柴油复配混合燃料的互溶性、密度、运动黏度、闭口闪点、馏程、冷凝点、冷滤点等理化性质进行测试研究。结果表明:低温下乙酰丙酸乙酯与0#柴油互溶性较差,5℃时最大互溶比仅为7%,随着温度升高,溶解度有所上升,在35℃条件下最大互溶比为15%。随着复配燃料中乙酰丙酸乙酯所占比例增加,复配燃料的十六烷值逐渐降低;对馏程影响不明显,密度增幅不大;闪点较石化柴油有所提高,这有利于燃料的安全储存;热值出现小幅下降;运动黏度、凝点和冷滤点低温流动性改善明显。总体来看:掺混比小于或等于7%的乙酰丙酸乙酯复配燃料基本符合国六柴油GB 19147—2016标准;如需提高乙酰丙酸乙酯复配比例,有必要对热值、十六烷值等指标进行改进,以满足国六柴油标准要求。

基于己酸菌微胶囊的无窖泥发酵浓香型白酒工艺研究

该研究将己酸菌复合菌液微胶囊化,以期替代窖泥发酵生产浓香型白酒。通过将己酸菌微胶囊与酒醅混合发酵,对加曲量、发酵时间、己酸菌微胶囊添加量和添加方式进行单因素试验,测定发酵结束后酒醅及酒体理化指标、风味物质含量,并结合多元统计分析方法,对影响发酵的主要因素进行探究。结果表明,不同发酵条件下酒醅中水分含量无明显差异,己酸乙酯含量受发酵条件变化影响比较明显。所得浓香型白酒中共检测到96种物质,其中酯类、醇类物质种类及含量占比最高,受发酵条件变化影响最大,发酵时间和加曲量是对酒体风味物质变化影响最显著的2个因素。己酸乙酯与己酸菌微胶囊添加量、发酵时间、加曲量呈正相关,与己酸菌微胶囊添加量相关性最强。该研究可为无窖泥发酵生产浓香型白酒提供参考。

乙酸乙酯、乳酸乙酯和己酸乙酯的两种定量方法在老白干白酒中的应用研究

老白干香型白酒中乙酸乙酯与乳酸乙酯为主体香气,己酸乙酯含量极低,在GB/T10345-2022《白酒分析方法》的应用中,作者降低了己酸乙酯标准溶液的浓度,使标准曲线浓度范围更多覆盖样品浓度。进行了老白干原酒样品试验,对乙酸乙酯,乳酸乙酯和己酸乙酯的含量运用标准曲线法和校正因子法进行分析。在实验过程中,校正因子定量法操作简单快捷,缺点是在远离单点校正点时或含量较小时,相对误差较大,方法要根据混标来确定校正因子,既要根据仪器状态及时调整校正因子,又要保证混标各成分含量的准确性。而标准曲线法是在试验所有浓度范围都有较好的准确度,缺点是乙酸乙酯、己酸乙酯、乳酸乙酯都极易挥发,称取容易有误差,标准原液配制时环境温度和操作有严格要求。在老白干酒的检测中,试验获得标准曲线定量法准确度更高。

棕榈酸乙酯含量对特香型白酒感官的影响

本研究旨在探讨低温环境下(-8℃以下)棕榈酸乙酯含量对特香型白酒感官的影响,通过实验探究,确定棕榈酸乙酯含量与低温絮凝物量的关系。研究结果显示,低度酒(≤45%vol)的棕榈酸乙酯含量≤0.03 g/L、高度酒(>45%vol)的棕榈酸乙酯含量≤0.04 g/L时,在-8℃的低温环境下酒体仍能保持清亮透明未见明显絮凝物,随着棕榈酸乙酯含量的增加,絮凝物逐渐增多,二者含量在酒体中呈正比关系。

两种乙酸乙酯制备方法的比较

乙酸乙酯的制备是大学有机化学的一个基础制备实验,但存在两种不同的制备方法:回流法和分馏法。通过探讨这两种制备方法的不同,以期培养学生独立思考能力、分析问题及解决问题能力、探索精神等品质。采用分组实验的方式,引导学生分析、比较、解释这两种制备方法之间的差异。结果表明,当乙醇和乙酸的体积比为3:2时,回流法的产率达到87.84%,而分馏法的产率却只有77.60%。回流法制备时,浓硫酸的用量可大大降低至0.5 mL。回流法是更佳的制备方法。分组实验法对培养学生的好奇心和探索精神有一定的帮助。

白酒大曲中氨基甲酸乙酯降解菌株的筛选及共发酵培养条件的优化

为降低白酒发酵过程中有害副产物氨基甲酸乙酯(ethyl carbamate,EC)的含量,本研究从大曲中筛选得到具有降解EC能力且发酵性能优良的细菌和酵母菌,采用响应面法优化了2株菌共发酵培养条件并应用于白酒发酵。结果表明:从白酒大曲中获得EC降解酶活力较高的5株酵母菌和4株细菌,进一步分析其产酯能力和蛋白酶活性,得到具有优良发酵性能的解淀粉芽孢杆菌JX2-10(Bacillus amyloliquefaciens)和异常威克汉姆酵母QX-2(Wickerhamomyces anomalus);在24 h内JX2-10和QX-2的EC降解率分别达到85%和35%;通过单因素试验和响应面试验优化出JX2-10和QX-2共发酵的最佳产蛋白酶和总酯条件为初始pH 5.6、培养温度30.1℃、乙醇体积分数3.9%,该条件下蛋白酶活力为41.59 U/mL、总酯质量浓度为5.85 g/L;应用于白酒发酵,发酵结束后实验组的酒醅及白酒中EC质量浓度与对照组相比分别减少了12.7%和10.8%,且能增加白酒挥发性风味物质含量。本研究可为白酒发酵过程中EC的降解提供数据基础。

Preparation of Ni(HCO_3)_2 and its catalytic performance in synthesis of benzoin ethyl ether

Ni（HCO3）2 with unique phase and high crystallinity was synthesized with urea hydrolysis. The as-prepared samples were well characterized in detail. N2 adsorption and desorption result manifests a high surface area of 99.03 m2/g with a pore size of 7.8 nm. Scanning electron microscopy （SEM） and particle size distribution reveal that the diameters of the formed pellets are uniform. Thermogravimetry （TG） analysis result shows that 500 ℃ could be the appropriate temperature for converting Ni（HCO3）2 precursors into NiO via a thermal decomposition process. CO2 and NH3 temperature-programmed desorption results show that Ni（HCO3）2 has explicit acid-base sites. Transmission electron microscopy （TEM） results vividly indicate that the pellets are aggregated by hexagonal platelets and possess porous structures. Ni（HCO3）2 can efficiently catalyze the one-step synthesis of benzoin ethyl ether from benzaldehyde and ethanol, with the conversion ofbenzaldehyde up to 57.5% and nearly 100% selectivity of benzoin ethyl ether.

氮肥和Trinexapac-ethyl配合施用对草地早熟禾草坪生长的影响

【目的】探明氮肥和Trinexapac-ethyl(TE)配合施用对草地早熟禾草坪生长的影响。【方法】在草地早熟禾返青后,采用完全随机区组设计,氮肥设0(N1)、20(N2)、25(N3)和30(N4)kg·ha-14个水平,每月施1次;TE设0(T1)、312.5(T2)和625(T3)ml·ha-13个水平,每10d喷施1次,测定氮肥和TE配合施用对草坪株高、产草量及叶绿素含量的影响。【结果】施氮能显著促进草坪生长,而喷施TE能够显著抑制草坪的生长。在不同的氮肥水平上,T2处理能够降低草坪新增株高、剪草量达30%左右,T3处理能够降低草坪新增株高、剪草量达45%左右。在保证正常需要的同时,N2T3、N3T3、N4T3处理的草坪生长较慢。氮与TE的交互作用对草坪颜色有极显著影响;相同氮水平处理中,T3处理草坪草叶绿素含量显著高于T1处理;N4T3处理草坪颜色最深。【结论】以草坪生长与叶绿素含量为评判的依据,最好的组合为N2T3、N4T3,它们均能使草坪生长减慢而且颜色加深。

MCPB-ethyl对富士苹果疏花效果的研究

探讨了MCPB-ethyl的喷布时期、喷布浓度对富士苹果的疏花效果、果实发育和果实品质的影响。试验证明,MCPB-ethyl是一个良好的苹果疏花剂,有效喷布期是中心花盛开后1-5 d,最适喷布期是中心花盛开后1-3 d;最适喷布浓度为15 mol/L,对果实发育、果形、果实着色和果实品质无不利影响。

降解氨基甲酸乙酯的酯酶挖掘及酶学性质表征

本研究在NCBI数据库中挖掘出4个在pH 4.5及7.0条件下均具有氨基甲酸乙酯(ethyl carbamate,EC)降解能力的酯酶(ES1、ES5、ES8和ES9),实现它们在大肠杆菌中的可溶性表达,并对其进行纯化及酶学性质表征。结果表明,ES1、ES5、ES8和ES9最适温度分别为70、70、55℃及55℃,ES1、ES5、ES9最适pH值呈碱性,ES8呈中性;4种酶在温度高于45℃或pH值低于5.0条件下稳定性显著降低;4种酶的活性受到Fe^(3+)、Co^(2+)、Cu^(2+)的强烈抑制;4种酶在体积分数10%乙醇存在条件下,可分别保持50.48%、48.44%、42.60%及33.59%的酶活力。4种酶在质量分数为5%NaCl条件下,可分别保持24.09%、20.41%、16.11%及10.73%的酶活力。4种酶在pH 4.5条件下对EC的米氏常数(Km)值分别为210.7、213.8、256.2 mmol/L及127.2 mmol/L,催化常数(kcat)/米氏常数(Km)值分别为214.31、203.20、161.46 L/(mol·s)及257.43 L/(mol·s)。结构分析推测,ES9底物通道入口较窄,可能影响EC的进入,从而影响ES9对EC的最大反应速率;而ES9具有相对较高的EC亲和力,可能归因于ES9与EC之间较强的氢键作用力。本研究获得了具有良好乙醇耐受性及EC水解性能的酯酶,丰富了EC水解酶酶库,为未来控制低酒精度的传统发酵食品中EC含量提供了新方法。

Trinexapac-ethyl、Prohexad ione-Ca在草坪化学控制中的应用研究

为探明Trinexapac-ethyl和Prohexadione-Ca用于草坪化学控制的可行性,研究了其对高羊茅(Festuca arundinacea)生长发育的影响.结果显示:使用剂量高于0.095 kg/hm2时, Trinexapac-ethyl对高羊茅具有明显的矮化作用,在0.36 kg/hm2剂量下Prohexadione-Ca的抑制率可达95.2%;Trinexapac-ethyl和Prohexadione-Ca都能使植株新增鲜重显著降低,但对新增干重影响很小,Trinexapac-ethyl对植株新增干重无影响;在施用Trinexapac-ethyl的情况下,随着留茬高度的增加新增株高减少,合理留茬高度为4～6 cm;Trinexapac-ethyl和Prohexadione-Ca可以有效降低株高,从而减少草坪修剪次数.

雷帕霉素产生菌突变株FC904-107发酵产生7-O-ethyl-rapamycin

在雷帕霉素产生菌吸水链霉菌FC904突变株FC904-107的发酵液中发现一个雷帕霉素同系物FIM-4025,用反相硅胶柱层析等提取纯化并获得晶体。经理化性质、UV、IR、LC-MS、NMR等波谱分析,单晶X-Ray衍射确定构型,结果表明雷帕霉素同系物FIM-4025与雷帕霉素化学半合成的衍生物7-O-乙基雷帕霉素同质。

酱香型白酒酿造过程中氨基甲酸乙酯前体来源解析

氨基甲酸乙酯(ethyl carbamate,EC)广泛存在于白酒中,由于其具有致癌性,对我国白酒品质和国民健康产生了负面影响,因此明确其形成机制十分必要。但酱香型白酒生产工艺复杂,EC的形成机制尚不清楚。该研究旨在明确酱香型白酒酿造过程中EC前体的来源,分析不同工艺阶段中的EC前体含量变化规律,为进一步明确EC的形成机制奠定基础。通过检测分析不同原辅料中EC前体含量,明确了EC前体的主要来源是大曲。通过检测分析不同工艺节点的EC及其前体的含量,明确了酱香型白酒中EC的主要形成阶段是蒸馏阶段,氰化物是蒸馏阶段的主要前体。模拟反应实验表明,高粱中的蜀黍糖苷是氰化物的主要来源,这一结论也与氰化物在发酵过程中的含量变化规律相符。最后,从白酒酒醅中筛选得到了一株与生氰糖苷形成氰化物密切相关的热带假丝酵母(Candida tropicalis)。该结果为后续调控酱香型白酒中的EC含量提供了思路。

High mobility group box 1 in the central nervous system:regeneration hidden beneath inflammation

High-mobility group box 1 was first discovered in the calf thymus as a DNA-binding nuclear protein and has been widely studied in diverse fields,including neurology and neuroscience.High-mobility group box 1 in the extracellular space functions as a pro-inflammatory damage-associated molecular pattern,which has been proven to play an important role in a wide variety of central nervous system disorders such as ischemic stroke,Alzheimer’s disease,frontotemporal dementia,Parkinson’s disease,multiple sclerosis,epilepsy,and traumatic brain injury.Several drugs that inhibit high-mobility group box 1 as a damage-associated molecular pattern,such as glycyrrhizin,ethyl pyruvate,and neutralizing anti-high-mobility group box 1 antibodies,are commonly used to target high-mobility group box 1 activity in central nervous system disorders.Although it is commonly known for its detrimental inflammatory effect,high-mobility group box 1 has also been shown to have beneficial pro-regenerative roles in central nervous system disorders.In this narrative review,we provide a brief summary of the history of high-mobility group box 1 research and its characterization as a damage-associated molecular pattern,its downstream receptors,and intracellular signaling pathways,how high-mobility group box 1 exerts the repair-favoring roles in general and in the central nervous system,and clues on how to differentiate the pro-regenerative from the pro-inflammatory role.Research targeting high-mobility group box 1 in the central nervous system may benefit from differentiating between the two functions rather than overall suppression of high-mobility group box 1.

氮肥和Trinexapac-ethyl对草地早熟禾草坪生长的影响

[目的]探明氮肥和Trinexapac-ethyl(TE)对草地早熟禾草坪生长的影响。[方法]采用随机区组设计对草地早熟禾草坪的剪草量及颜色进行评定。其中,氮肥设4个水平:0(N1)、20(N2)、25(N3)、30(N4)kg/(hm2·month),TE设3个水平0(TE1)、312.5(TE2)、625.0(TE3)ml/(hm2·10d)。[结果]不同氮素水平和不同TE水平处理间,剪草量在各个时期差异都达极显著水平(P<0.01);N与TE的互作对草坪草剪草量影响差异不显著;在试验的各个时期,不同氮素水平下,TE2、TE3处理都比TE1处理的剪草量显著降低。不同氮素水平处理间,叶绿素含量在各个时期差异均达极显著水平(P<0.01),不同TE水平处理间以及N与TE的互作效应对草坪叶绿素含量影响在6月份后达到极显著水平(P<0.01)。在试验中,在不同时期4个氮素水平的叶绿素含量均是TE3处理含量高于TE1处理。[结论]在各个氮素水平下,使用TE均能够抑制草坪生长,改善草坪颜色。