Rational design of MoS_(2)-based catalysts toward lignin hydrodeoxygenation:Interplay of structure,catalysis,and stability

The MoS_(2)-based materials are a vital class of heterogeneous catalysts for the hydrodeoxygenation of lignin and its model compounds to produce value-added chemicals especially because of their unique selectivity to aromatics.The rational design of MoS_(2)-based catalyst greatly depends on the comprehensive understanding of its structure-activity relationship.However,an intensive summary and critical analysis are still scarce to date.In this review,we attempt to provide an in-depth understanding of the interplay of structure,catalysis,and stability of MoS_(2)-based catalysts for lignin hydrodeoxygenation.The recognition of intrinsic active sites on MoS_(2) structure was firstly discussed,followed by the illustration of MoS_(2)-catalyzed hydrodeoxygenation structural models.Afterward,based on the studies on the MoS_(2)-catalyzed lignin model compounds hydrodeoxygenation,the current active site modification strategies including structural modification of monometallic MoS_(2) catalysts and collaborative modification were summarized and emphatically discussed,which aims to elucidate the structure-activity relationship at the atomic-level.The deactivation mechanism and stabilization strategies were also illustrated to provide instructive suggestion for the rational design of efficient and stable MoS_(2)-based catalysts.Finally,the real lignin depolymerization over MoS_(2)-based catalysts was summarized to point out the advantages and difficulties.This review attempts to highlight the remaining challenges and provide some perspectives for the future development of MoS_(2)-based catalysts for lignin hydrodeoxygenation.

“雨课堂+翻转课堂”在医学类化学实验微课教学中的应用及效果探讨

医学类化学实验的课程是医学类专业课程学习、实践的基础,其目的主要是培养大学生实验技能,在整个医学类教育体系中有着不可或缺的地位。结合具体的教学实践,探讨“雨课堂+翻转课堂”在化学实验微课教学中的应用情况,并通过问卷调查和对照教学等方法深入分析翻转课堂的有效性,为教育研究者提供参考。

MgFe hydrotalcites-derived layered structure iron molybdenum sulfide catalysts for eugenol hydrodeoxygenation to produce phenolic chemicals

Hydrodeoxygenation（HDO） is an effective alternative to produce value-added chemicals and liquid fuels by removing oxygen from lignin-derived compounds. Sulfide catalysts have been proved to have good activity for the HDO and particularly high selectivity to phenolic products. Herein, we presented a novel way to prepare the layered structure sulfide catalysts（MgFeMo-S） derived from MgFe hydrotalcites via the intercalation of Mo in consideration of the memory effect of the calcined hydrotalcite. By varying the Mg/Fe mole ratio, a series of MgFeMo-S catalysts were successfully prepared and characterized by nitrogen adsorption/desorption isotherms, X-ray diffraction（XRD）, transmission electron microscopy（TEM）,and inductively coupled plasma optical emission spectrometer（ICP-OES）. The characterization results indicated that the MgFeMo-S catalyst has retained the unique layered structure, which can facilitate uniform dispersion of the MoS2 species on both the surface and interlayer of the catalysts. For the HDO of eugenol, the Mg1Fe2Mo-S catalysts exhibited the best HDO activity among all the catalysts due to its higher active metal contents and larger pore size. The HDO conversion was 99.6% and the yield of phenolics was 63.7%, under 5 MPa initial H2 pressure（measured at RT） at 300 ℃ for 3 h. More importantly,MoS2 species deposited on the interlayer galleries in the MgFeMo-S catalysts resulted in dramatically superior HDO activity to MoS2/Mg1Fe2-S catalyst. Based on the mechanism investigation for eugenol, the HDO reaction route of eugenol under sulfide catalytic system has been proposed for the first time. Further applicability of the catalyst on HDO of more lignin-derived compounds was operated, which showed good HDO activity and selectivity to produce aromatic products.

8种水生蔬菜清除水溶性ABTS^+自由基活性研究

为评价水生蔬菜的抗氧化活性,采用超声破碎提取制备8种水生蔬菜的水提取物,研究提取物与ABTS^+自由基反应的紫外可见吸收光谱特征。结果表明,8种水生蔬菜提取物对ABTS^+自由基734 nm处吸收峰值随水生蔬菜用量增加呈剂量效应关系,相对于DPPH自由基清除试验基于517 nm处的吸收峰测量,ABTS^+自由基734 nm处吸收峰测量避免了水生蔬菜色素的光谱干扰,且ABTS^+自由基水溶性特点更适于日常饮食的抗氧剂摄入评价。8种水生蔬菜提取物的半数抑制浓度依次为:茭瓜(4.111 mg/mL)>慈姑(2.932 mg/mL)>荸荠(2.517 mg/mL)>海菜(2.413 mg/mL)>水芹菜(1.795 mg/mL)>水芋(1.594 mg/mL)>莲藕(0.974 mg/mL)>水蕨菜(0.140 mg/mL),水蕨菜具有最强的自由基清除活性。

三种云南产鲜花醇提液对ABTS自由基的清除作用

以3种常见食用花卉(玫瑰花、菊花、茉莉花)为原材料,经乙醇浸提得鲜花醇提液,考察了鲜花醇提液对ABTS自由基的清除作用。结果表明,浓度为2.5mg·mL^(-1)时,玫瑰花、菊花和茉莉花醇提液对ABTS自由基的清除率分别为80.61%、93.90%和83.71%,对ABTS自由基的半数抑制浓度(IC50值)分别为1.15mg·mL^(-1)、1.02mg·mL^(-1)和1.21mg·mL^(-1),其中菊花醇提液清除ABTS自由基的能力最强。食用玫瑰花、菊花、茉莉花醇提液均对ABTS自由基具有较强的清除作用,可作为天然抗氧化剂加以开发。为开发和利用云南鲜花资源作为天然高效食品抗氧化剂提供了理论依据。

7种云南可食用昆虫醇提液对ABTS+自由基清除作用

本文研究7种云南常见可食用昆虫对ABTS+自由基的清除作用。采用超声破壁技术提取制备7种可食用昆虫的乙醇提取物,研究加热对可食用昆虫ABTS+自由基清除能力的影响。通过线性拟合计算获得ABTS+自由基清除的半数抑制浓度IC50值。结果表明:所测7种可食用昆虫中ABTS+自由基清除能力最强的为金蝉,最弱的为虾巴虫。7种可食用昆虫经过烹饪加热后其醇提液ABTS+自由基清除能力均有不同程度改变,其中金蝉以及虾巴虫ABTS+自由基清除率分别升高36.2%和31.4%,竹虫和蝗虫分别降低19.3%和12.8%,柴虫、蜂蛹和蚕蛹变化不大。7种可食用昆虫醇提液均对ABTS+自由基具有良好的清除作用,且富含蛋白质氨基酸,营养价值高,具有很好的开发利用价值。本文实验方法简单、可靠,为居民日常生活中合理食用昆虫提供参考。

思维导图在医用化学教学中的应用初探

医用化学这门学科知识点比较抽象、概念多而分散,导致学生对知识点的掌握难度较大。实践证明将思维导图这一新型的教学辅助工具应用到教学中,能优化课堂教学,提高教学质量,为学生提供有趣、高效的学习方法,培养学生自主学习的良好习惯。本文通过列举一些知识点的思维导图的构建,分别从"教"与"学"两个角度阐述思维导图在医用化学教学实践中的有效应用,能为教学改革提供有意义的参考价值。

学龄前儿童维生素A、锌营养状况与体格生长的相关性

目的分析儿童维生素A、锌营养状况对学龄前儿童生长发育影响,并提出相应的干预措施。方法选取2016年2月-2018年2月在我院进行健康体检的2000名儿童为研究对象,根据性别分为男性组和女性组,取儿童血样进行维生素A水平检测,然后再根据儿童的血样检测结果再次分为两组,维生素A缺乏组及维生素A正常组;给予儿童检测维生素A水平的同时测量所有儿童的身高及血清锌水平.一年之后联系儿童家长,再次测量每个儿童的身高值及血清锌水平,分析得维生素A水平与儿童生长发育的相关性。结果维生素A正常组儿童的平均身高均显著高于维生素A缺乏组(P<0.05);维生素A正常组儿童的平均血清锌水平显著高于维生素A缺乏组(P<0.05)。结论在儿童的生长发育过程中,维生素A、锌与儿童的体格生长具有非常密切的关系;儿童维生素水平缺乏情况,应当引起全社会的重视,并采取积极的干预措施,以防止儿童维生素缺乏症及并发症的发生。

一种猪伪狂犬病病毒gE基因TaqMan荧光定量PCR检测方法的建立

研究旨在建立一种猪伪狂犬病病毒(PRV)的探针法荧光定量检测方法。选用PRV gE基因为靶基因,比对不同野毒在该基因的保守区域设计特异性引物和探针,构建PRV gE基因片段的重组质粒作为标准品,对该方法的反应体系和条件进行优化,并进一步评估该方法的敏感性、特异性和稳定性,最后与商品化试剂盒同时检测临床样本,比较符合率。结果表明,该研究建立的T a q M a n荧光定量P C R检测方法的最佳反应条件为上下游引物和探针量分别为0.2μm o l/L和0.05μm o l/L,最佳退火温度为58℃。该方法具有良好的特异性,对PRV Bartha-k61疫苗株、猪流行性腹泻病毒(PEDV)、猪细小病毒(PPV)、猪A群轮状病毒(PoRV)、猪德尔塔冠状病毒(PDCoV)、猪传染性胃肠炎病毒(TGEV)、猪链球菌(S.suis)、猪源大肠杆菌(E.coli)、猪源巴氏杆菌(P.multocida)、猪霍乱沙门氏菌(S.choleraesuis)和葡萄球菌(S.aureus)等11个菌毒种均无非特异性扩增。该方法的最低检测限为3.92 copies/μL。重复性试验结果显示,组内和组间变异系数均≤2%。与商品化的荧光定量PCR检测试剂盒比较,符合率均为100%(n=50)。综上所述,该研究建立了一种灵敏高效的检测PRV野毒株的TaqMan荧光定量PCR方法,该方法可以成为猪伪狂犬病早期快速诊断和流行病学调查的一种可靠的技术手段。

体外模拟胃肠消化对云南苦荞米饭抗氧化成分及其活性的影响

本文以空白实验为对照,分别对云南苦荞米饭进行了体外胃、肠模拟消化实验,采用NaNO;Al(NO;);比色法及ABTS+自由基清除率测定苦荞米饭体外模拟胃肠消化时黄酮释放量及抗氧化活性的变化,探讨其对苦荞米饭抗氧化成分及其活性大小的影响。结果表明,苦荞米饭在模拟胃消化中黄酮释放量和ABTS+自由基清除率均明显上升,模拟胃消化组1.5 h内上升趋势明显,最大增加值分别为空白对照组的1.91倍和1.67倍,之后趋于稳定。胃酸对照组最大增加值分别为空白对照组的1.26倍和1.36倍,之后变化平稳。模拟肠消化组1.5 h内最大增加值分别为空白组的1.45倍和1.11倍,之后变化趋于稳定,表明胃蛋白酶、胃酸和胰酶促进了云南苦荞米饭中抗氧化成分的释放及其活性的增加。

独立医科院校青年教师化学教学中存在的问题及对策

化学是高等医科院校医药学类专业一年级学生的一门公共基础课,学好化学知识可为医学生后续学习医学课程、开展临床实践奠定良好的基础。为提高独立医科院校化学课程的教学质量,针对我校青年教师目前在化学教学中存在的优势与不足进行了分析,提出应提高对本职工作的热爱程度,采取多听课多试讲、苦练教学基本功、充分利用多媒体与网络教学手段、坚持“以教学为中心,以科研促教学”等措施,以期为青年教师早日成长为骨干教师提供借鉴。

独立医科院校新生有机化学实验室安全教育研究

有机化学实验室是我校培养医学生实验技能和科技创新能力的重要场所。本文结合独立医科院校新生实验动手能力偏弱的实际情况和有机化学实验自身的特点,阐述了对我校一年级新生进行化学实验安全教育的重要性,提出了对新生实验安全教育的措施。

Hydrogen production from steam reforming of biomass-derived levulinic acid over highly stable spinel-supported Ni catalysts

As one of the main oxygen-containing organic products generated from the hydrothermal conversion of biomass,levulinic acid(LA)has the potential to be further upgraded.This work investigated the steam reforming(SR)process of biomass-derived LA to produce H_(2).A series of Ni catalysts supported by various spinels were synthesized via co-precipitation and impregnation.The Ni active metal dispersed well on the NiAl_(2)O_(4)catalyst with high specific surface area,thereby exhibiting high catalytic activity.Among all the catalysts tested,15Ni/NiAl_(2)O_(4)showed the best performance for SR of LA,resulting in high carbon conversion of 96.3%,H_(2)yield of 92.8%,and H_(2)concentration of 67.9%at a reaction temperature of 800℃.Additionally,the influences of reaction temperature,steam-to-carbon ratio(S/C),and liquid hourly space velocity(LHSV)were also examined.Moreover,during the 40-h continuous SR process of LA,the 15Ni/NiAl_(2)O_(4)catalyst maintained its outstanding catalytic activity.This study provides an encouraging route for upgrading biomass-derived LA into eco-friendly and high-value fuels,thereby advancing the sustainability of the biomass refining process.

Potential applications of porous organic polymers as adsorbent for the adsorption of volatile organic compounds

Volatile organic compounds(VOCs)with high toxicity and carcinogenicity are emitted from kinds of industries,which endanger human health and the environment.Adsorption is a promising method for the treatment of VOCs due to its low cost and high efficiency.In recent years,activated carbons,zeolites,and mesoporous materials are widely used to remove VOCs because of their high specific surface area and abundant porosity.However,the hydrophilic nature and low desorption rate of those materials limit their commercial application.Furthermore,the adsorption capacities of VOCs still need to be improved.Porous organic polymers(POPs)with extremely high porosity,structural diversity,and hydrophobic have been considered as one of the most promising candidates for VOCs adsorption.This review generalized the superiority of POPs for VOCs adsorption compared to other porous materials and summarized the studies of VOCs adsorption on different types of POPs.Moreover,the mechanism of competitive adsorption between water and VOCs on the POPs was discussed.Finally,a concise outlook for utilizing POPs for VOCs adsorption was discussed,noting areas in which further work is needed to develop the next-generation POPs for practical applications.