Preparation, Characterization of Solid Solution La_4BaCu_(5- x)Mn_xO_(13+λ)(x= 0—5) and ItsCatalytic Activity in the Reduction of NO by CO

A series of layered mixed oxides La 4BaCu 5-x Mn x O 13+λ ( x =0—5) was prepared, characterized and used as catalysts for NO+CO reaction. It was found that all the samples were single phase having a structure with five layered perovskite. La 4BaCu 2Mn 3O 13+λ showed the highest activity in the title reaction, this could be attributed to the synergetic effect between Cu and Mn. The results of TPR, TPD and excess oxygen investigations confirmed that the Cu ion would be the active center. The displacement of the Cu ion by Mn caused the Cu ion to be more easily reducible and more content of excess oxygen, and it was beneficial to the activity of the catalyst. The reaction mechanism was also proposed.

Protection of Salvianolic Acid B for Human Endothelial Cells Against Hydrogen Peroxide-Induced Oxidative Damage

Salvianolic acid B(Sal B) is an active component of traditional Chinese medicine Salvia miltiorrhiza and is used to treat vascular diseases. To better understand its mechanism, the antioxidant capacities of Sal B was evaluated with human endothelial cells under oxidative stress. Human endothelial cells were pretreated with Sal B for 12 h followed by hydrogen peroxide for another 12 h. Production of reactive oxygen species (ROS), activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX), and concentration of glu-tathione were measured. Protective effect of Sal B on the endothelial cells from hydrogen peroxide-induced damage was observed, and ROS production in the cells was found significantly inhibited. Sal B remarkably enhanced the activities of antioxidant enzymes SOD, CAT and GPX. Furthermore, Sal B up-regulated the intracellular glu-tathione concentration. The results indicate that Sal B protected endothelial cells from oxidative stress by improving the redox status of the cells through enhancing the antioxidant enzyme activities and increasing the reductive glu-tathione concentration after the oxidative challenge.

Efficient electroreduction of nitrate via enriched active phases on copper-cobalt oxides

Electrochemical conversion of nitrate(NO_(3)~-) to ammonia(NH_(3)) can target two birds with one stone well, in NO_(3)^(-)-containing sewage remediation and sustainable NH_(3) production. However, single metalbased catalysts are difficult to drive high-efficient NO_(3)~- removal due to the multi-electron transfer steps.Herein, we present a tandem catalyst with simple structure, Cu-Co binary metal oxides(Cu-Co-O), by engineering intermediate phases as catalytic active species for NO_(3)~- conversion. Electrochemical evaluation,X-ray photoelectron spectroscopy, and in situ Raman spectra together suggest that the newly-generated Cu-based phases was prone to NO_(3)~- to NO_(2)~- conversion, then NO_(2)~- was reduced to NH_(3) on Co-based species. At an applied potential of -1.1 V vs. saturated calomel electrode, the Cu-Co-O catalyst achieved NO_(3)~- -N removal of 90% and NH_(3) faradaic efficiency of 81% for 120 min in 100 m L of 50 mg/L NO_(3)~- -N,consuming only 0.69 k Wh/mol in a two-electrode system. This study provides a facile and efficient engineering strategy for developing high-performance catalysts for electrocatalytic nitrate conversion.

多酶偶联催化制备手性化合物(S)-环氧苯乙烷

在水/有机两相中将羰基还原酶SyS1、葡萄糖1-脱氢酶SyGDH和卤代醇脱卤酶CSyHheC偶联催化α-溴代苯乙酮以高效制备(S)-环氧苯乙烷(SO)。第1步反应催化α-溴代苯乙酮不对称还原为(S)-2-溴-1-苯基乙醇((S)-BPE)及NADPH的原位再生,其优化的反应条件:100 mmol/L磷酸钾缓冲液(p H 8.0)/正己烷(V∶V=4∶6)、40 mmol/Lα-溴代苯乙酮、80 mmol/LD-葡萄糖、0.2 mmol/L NADP+和70 mg/m L E.coli/Sygdh-Sys1湿菌体(共表达SyGDH和SyS1),终体积1.0 m L,35℃反应8 h。第2步反应催化(S)-BPE脱卤闭环为(S)-SO,其反应条件:在上述反应体系中加入磷酸钾缓冲液(p H 8.0)和0.3 U SyHheC,终体积2.0 m L,35℃反应30 min。通过连续2步酶催化反应,终产物(S)-SO的摩尔产率为99%、对映体过量值>99%。

Synthesis of 3-O-Benzoyl-1 ,2-O-isopropylidene-a-D-allofuranose and Its Dimesylated Derivative

Diisopropylidenated α-D-glucofuranose （1） was oxidated with CrO3-pyridine complex. Oxidated product and its hydrate were separated and were reduced together to synthesize diisopropylidenated α-D-allofuranose （ 3）. The yield of 3 increased by 8% than that with only oxidated product as reduction substrate. Benzoylated derivative of 3 was selectively nydrolyzed and dimesylated to synthesize 3-O-benzoyl-1 .2- O- isopropylidene-α-D-allofuranose （ 5 ） and its dimesylated derivative respectively. The overall yield of 5 from 1 was 36%. Each step and final products were analyzed by ^1H-NMR spectra and other methods. The experiments showed that the influence of acetic acid concentration on selective hydrolysis was obvious. The hydrolysis yield was 81.8%. Oxidation. reduction and other procedures were practical and had application potential.

Layered La-Ba-Cu mixed oxides with perovskite structure as catalyst for NO reduction by CO

The mixed oxides, including LaBa\-2Cu\-3O\-7, LaBaCu\-2O\-5, La\-4BaCu\-5O 12 with perovskite structure, were prepared. The catalysts were characterized by means of chemical analysis, XRD, H\-2_TPR. It was found that their structures were layered ABO\-3 perovskite structure and they were the active catalysts for the NO reduction by CO. The existance of Cu 3+ is an important factor to give the catalysts a high activity for the NO reduction by CO.

In^(3+)-doped Sr_(2)Fe_(1.5)Mo_(0.5)O_(6−δ)cathode with improved performance for an intermediate-temperature solid oxide fuel cell

Promoting the oxygen reduction reaction(ORR)is critical for commercialization of intermediate-temperature solid oxide fuel cells(IT-SOFCs),where Sr_(2)Fe_(1.5)Mo_(0.5)O_(6)−δ(SFM)is a promising cathode by working as a mixed ionic and electronic conductor.In this work,doping of In^(3+)greatly increases the oxygen vacancy concentration and the content of adsorbed oxygen species in Sr_(2)Fe_(1.5)Mo_(0.5−x)InxO_(6−δ)(SFMInx),and thus effectively promotes the ORR performance.As a typical example,SFMIn_(0.1)reduces the polarization resistance(R_(p))from 0.089 to 0.046Ω∙cm^(2)at 800°C,which is superior to those doped with other metal elements.In addition,SFMIn0.1 increases the peak power density from 0.92 to 1.47 W∙cm^(−2)at 800°C with humidified H_(2)as the fuel,indicating that In3+doping at the Mo site can effectively improve the performance of SOFC cathode material.

氧化还原类酶活性在农业废弃物静态高温堆腐过程中变化的研究

以鸡粪和麦秸为原料，在静态通气条件下，研究了堆腐过程堆体温度及氧化还原酶活性变化。结果表明，添加微生物菌剂后，堆体不同部位温度均高于CK（不加微生物菌剂）处理，且升温阶段持续时间较短。微生物菌剂处理堆料50℃以上的持续时间为14～20d，CK处理50℃以上的持续时间7．5～10d；添加微生物菌剂处理的过氧化氢酶活性在第1～26d均大于CK处理；堆料中添加菌剂处理在堆腐中期的脱氢酶活性大于CK处理；添加菌剂处理在堆肥的第5～28d，多酚氧化酶活性大于CK处理的活性；说明微生物菌剂可促进有机物的降解及其降解产物的转化。添加菌剂处理在堆腐30d后E4／E6（为胡敏酸在465nm与665nm波长下吸光值的比值）比值为1．57～1．68，CK处理为2．16～2．41，表明添加菌剂能促进腐殖质的缩合和芳构化。

氧化还原类酶活性在小麦秸秆静态高温堆肥过程中的变化

选取小麦秸秆为试验材料,采取发酵罐处理方法,在静态通气条件下研究了堆腐过程中堆体温度变化、氧化还原类酶活性变化、温度与酶活性变化的关系、不同酶活性之间的关系。结果表明:(1)添加微生物菌剂处理较不添加微生物菌剂处理(CK)升温快、温度高、高温持续时间长;添加微生物菌剂处理堆体温度第2d上升到50℃以上,第3d达最高温度67.1℃,50℃以上持续6d;CK堆肥第3d达到50℃,第4d达最高温度59.5℃,50℃以上持续5d。(2)过氧化氢酶活性初期较低,中期迅速升高,并维持在较高水平,堆肥第10d到堆肥结束,添加微生物菌剂处理的过氧化氢酶活性明显高于CK;添加菌剂处理多酚氧化酶活性在堆肥前期和后期高于CK,说明添加菌剂可加速木质素的降解及其产物的转化;添加菌剂处理的脱氢酶活性在堆肥中期显著高于CK;添加菌剂处理的过氧化物酶从堆肥第12d到堆肥结束活性均高于CK的过氧化物酶活性,表明添加微生物菌剂可促进物质的氧化。(3)脱氢酶活性和过氧化物酶活性在堆肥中期达到最高值,两者变化趋势相同;过氧化氢酶活性、脱氢酶活性、过氧化物酶活性在堆腐后期比较稳定,多酚氧化酶活性堆腐后期呈增长趋势。

低氧化还原电位对铜绿微囊藻(Microcystis aeruginosa)生长的抑制及恢复的影响

在实验室光照黑暗交替培养下,用半胱氨酸下调黑暗起始时的氧化还原电位(ORP),研究低电位对铜绿微囊藻(Microcystis aeruginosa FACHB 469)生长的影响,并探索低电位胁迫消除后铜绿微囊藻生长的恢复潜力.结果表明,在-50～-100 mV范围内水体ORP越低,其对铜绿微囊藻生长的抑制作用越强.低ORP可抑制铜绿微囊藻对磷的吸收,且这种抑制程度与电位变化无关.-50～-75 mV的电位对铜绿微囊藻SOD酶活性有促进作用,而-90～-100 mV电位明显抑制SOD酶活.当低ORP胁迫消除后,铜绿微囊藻能够恢复至最初的生长状态,同时伴随含磷量的提高和SOD酶活的恢复,-50～-75 mV电位胁迫对藻消除胁迫后的生长更有促进作用.因此,低ORP对铜绿微囊藻的生长会产生不利影响,但是该影响是可逆的.

芹菜素对大鼠睾丸标志酶及氧化还原平衡的影响

本文主要探究芹菜素对雄性大鼠睾丸标志酶活力及氧化还原平衡的影响,并探讨其作用机制。通过将48只雄性SD大鼠随机分为4组,分别灌胃给予生理盐水(NS)10 mL/kg、芹菜素(AP)234、468、936 mg/kg 35 d,末次灌胃24 h后,测定大鼠睾丸标志酶及氧化还原平衡相关指标。结果发现,大鼠睾丸ACP、AKP、LDH活力及GSH含量显著降低(P<0.05),Ca2+Mg2+-ATP升高(P<0.05)。低剂量组SOD/(GSH-Px+CAT)降低,T-AOC升高,MDA降低(P<0.05),中剂量组SOD/(GSH-Px+CAT)升高,T-AOC升高(P<0.05),高剂量组SOD/(GSH-Px+CAT)升高,T-AOC降低(P<0.05)。结果表明芹菜素具有抗氧化和促氧化的双重作用。本实验中AP 234、468 mg/kg主要表现为抗氧化作用,936 mg/kg表现出促氧化作用。此外,AP 234、468、936 mg/kg能降低睾丸标志酶活力。

三氧化二砷对小鼠小脑氧化还原相关酶基因表达谱的影响

目的应用基因芯片技术观察三氧化二砷(As2O3)对小鼠小脑组织氧化还原相关酶基因表达谱的影响。方法昆明种小鼠30只随机分为3组,即生理盐水对照组、低剂量组(1 mg/L As2O3染毒组)和高剂量组(4 mg/L As2O3染毒组),连续染毒60 d,断头法处死小鼠,利用基因芯片技术检测基因表达谱的变化。结果基因芯片筛选结果显示,与对照组比较,染砷组中差异表达2倍及以上的基因有18条,其中表达上调的基因有12条,表达下调的基因有6条。高剂量组与低剂量组及对照组比较,表达上调的基因有Ndufa4、Ndufa6、Gpx3、Adi1、Rrm2b,表达下调的基因有Spr、Hsd17b11、Ogfod1、Ndufab1。与对照组比较,染砷组中Cyp51、Phgdh、Dhrs4、Prdx4、Aldh1a、1810063B05Rik、Glrx表达上调,Prdx2、1110020P15 Rik表达下调。结论As2O3对小鼠小脑的氧化还原相关酶基因表达谱具有明显的影响,提示这些小脑氧化还原相关酶基因很可能是砷的神经毒作用的靶点。

水双相法分离泡桐幼苗根细胞质膜的研究

通过对草本植物水双相法分离细胞质膜技术的改进 ,建立起木本植物泡桐根细胞质膜的分离纯化方法。其改进主要有 :在匀浆介质中添加了抗坏血酸 ,加大了聚乙烯聚吡咯烷酮的用量 ,由草本植物一般用量 0 0 5%～ 0 1 %增至 0 6% ;对第 1次双相分离后下相液中剩余的质膜进行了再回收。通过对质膜和细胞器各项标记酶指标的测定 ,确定了 6 3%的葡聚糖 (Dextran)T 50 0和 6 3%的聚乙二醇 (PEG) 4 0 0 0为主组成的两相系统分离的根细胞质膜具有较高的收率和纯度。该方法的建立为在细胞和分子水平上研究林木根系对离子吸收机理与生长发育的关系打下了基础。

广藿香油治疗皮肤光老化大鼠的效果研究及对p38MAPK/ERK通路蛋白的调控作用分析

目的对广藿香油治疗皮肤光老化大鼠的效果及对p38MAPK通路蛋白的调控作用进行分析,为临床治疗提供参考。方法 48只清洁级SD大鼠随机分为6组:对照组、模型组、PD98059组和广藿香油低、中、高剂量治疗组,每组8只。对照组大鼠给予正常光照射,其余各组采用长波段紫外线+中波紫外线(UVA+VUB)光源照射制备大鼠皮肤光老化模型。PD98059组和广藿香油组大鼠分别给予对应药物治疗,对照组给予生理盐水灌胃。分析各组大鼠血清中氧化还原酶、细胞凋亡蛋白及p38MAPK/ERK通路蛋白的表达。结果对照组皮肤无明显异常。模型组大鼠皮毛光泽度下降,皮肤颜色变深,且表皮干燥、粗糙、增厚、纹理增宽加深,弹性丧失;模型组大鼠血清中MDA、p38MAPK、Ras、Raf、MEK、ERK1/2、Bax、Caspase9及C-Fos和C-Jun水平明显升高而Bcl2、SOD、GSHPX和CAT蛋白水平明显降低(P<0.01),而广藿香油治疗后上述蛋白异常得到明显的恢复,且与治疗前比较差异有统计学意义(P<0.01);同时,广藿香油治疗具有剂量依从性,低剂量组、中剂量组和高剂量组之前差异有统计学意义(P<0.01)。结论藿香油治疗皮肤光老化大鼠的效果与其调控p38MAPK/ERK通路相关蛋白及Bax、Bcl2、C-Fos和C-Jun表达有关。

人参叶生长发育过程中几种氧化还原酶活力比较

目的:对五年生人参叶生长发育过程中苹果酸脱氢酶(Malate Dehydrogenase MDH),乳酸脱氢酶(Lactate de-hydrogenase LDH),乙醇脱氢酶(Alcohol dehydrogenase ADH),葡萄糖-6-磷酸脱氢酶(Glucose-6-phosphate Dehydro-genase G6PDH),α-磷酸甘油脱氢酶(α-Glycerophosphate dehydrogenaseα-GPD)5种氧化还原酶的活力进行比较,了解人参叶生长情况。方法:分别于展叶期、开花期、绿果期、红果期、枯萎期采取人参叶样品。采用中性缓冲液提取粗酶液,应用分光光度法测定MDH、LDH、ADH、G6PDH、α-GPD的活力。结果:在人参叶生长发育过程中,MDH、ADH和LDH活力在展叶期明显高于其他时期;LDH、G6PDH在展叶期和结果期末期活力最高;α-GPD在结果期出现活力峰值。结论:通过测量MDH、LDH、ADH、G6PDH、α-GPD的活力变化可判断人参生长情况。

生物还原剂的作用机理研究概况

乏氧现象存在于多数实体肿瘤中。生物还原剂是一种具有肿瘤乏氧靶向性的前药,它会在还原性环境中被还原产生具有细胞毒性的代谢物。目前,生物还原剂主要有硝基杂环类、杂环氮氧类、醌类等几类。生物还原剂不仅可以作为放射增敏剂、化学增敏剂,还可以用于基因向导的酶前药治疗(GDEPT)。总之生物还原剂的研究对未来恶性肿瘤治疗有很大的意义。

柿果实采后氧化还原电位与乙烯合成和相关酶活性的关系

该研究以广西特色柿品种‘恭城月柿’为材料,在采后贮藏过程中对其氧化还原电位(ORP)、乙烯生物合成量、硬度、色差、抗氧化酶及细胞壁降解酶活性的变化进行了测定,初步探讨柿果实氧化还原电位与乙烯生物合成和相关酶活性的关系。结果表明:贮藏期果实的硬度整体呈下降趋势,乙烯利处理果实的硬度从采后3 d即急速下降,至贮藏末期始终显著低于对照。贮藏前14 d果实转色较缓慢,采后15 d乙烯利处理果实的总色差ΔE值快速上升至29.6,转色完全,显著高于对照的11.9。在贮藏前期处理和对照果实的ORP均稳定在7.5 mv·g^(-1),采后15 d乙烯利处理果实的ORP快速上升至11.9 mv·g^(-1),是对照组的1.4倍。乙烯利处理果实的乙烯生物合成量在贮藏前期呈较低水平,采后15 d乙烯生成量急剧增加至0.372μL·kg^(-1)·h^(-1)的高峰,对照乙烯生成量则始终维持在0.033μL·kg^(-1)·h^(-1)的较低水平。可见,乙烯生成量的增加与ORP的上升关系密切。此外,抗氧化酶中的过氧化物酶(POD)和细胞壁降解酶中的β-D-半乳糖苷酶(β-D-Gal)活性与ORP呈极显著正相关,表明二者受果实ORP变化的影响。因此,经乙烯利处理柿果实的ORP贮藏末期显著上升,促进乙烯生物合成量的急剧增加,诱导抗氧化酶POD和细胞壁降解酶β-D-Gal活性增强,导致果实急速后熟软化。柿果实ORP可能作为开关调控1-氨基环丙烷-1-羧酸(ACC)生成乙烯这一生物化学反应,即打破ORP的稳定状态引发乙烯合成的启动。

真丝纤维/棉混纺织物染整工艺

真丝纤维/棉混纺织物采用还原漂白、酶处理、氧化漂白等前处理工艺处理,采取酸性染料与活性染料两浴法的生产工艺,各项物理指标达到货单要求,质量比较稳定。

面制品减盐技术及其应用

食盐是食品工业和居民日常生活中广泛使用的调味品,具有提供咸味,改善食品风味、质构和延长食品货架期等作用。但摄入过量的食盐会增加患高血压、冠心病等心血管疾病的风险。因此,在不影响食品口味和品质的条件下,减盐不减咸是目前研究的热点。面制品作为我国居民的日常主食之一,尽快推进减盐策略的实施对居民的健康有着重要的促进作用。本文探讨食盐在面团形成中的作用以及减盐给面制品带来的挑战,同时重点综述了无机盐替代技术、亲水胶体减盐技术、酶处理减盐技术、氧化还原减盐技术等面制品减盐策略,以期为减少居民膳食盐摄入量、提高居民的健康水平及开发减盐健康食品提供一定的技术参考。

高温胁迫对苦草、伊乐藻生长及水环境的影响

开展高温胁迫对苦草、伊乐藻生长及水质的影响试验。设置3个试验组,分别为A组、B组和C组,对应水温为25,35和39℃,每个试验组3个重复,为期30 d。结果表明,A组、B组和C组苦草比起始质量分别增长(120.2±27.5)%,(73.8±33.4)%和(-100.0±0.0)%;伊乐藻比起始质量分别增长(28.9±11.3)%,(-58.8±10.6)%和(-100.0±0.0)%。C组的伊乐藻从正式试验的第2天开始出现死亡,苦草在第7天出现部分根须及叶片腐解。B组苦草和伊乐藻在第2天CAT活力升高(P>0.05),MDA含量升高(P<0.05),苦草和伊乐藻SOD活性呈上升趋势。C组伊乐藻水体TP先大幅升高,后回落至初始水平。A组、B组和C组苦草水体TN分别降低了(65.3±16.5)%(P<0.01)(66.7±5.5)%(P<0.01)(39.8±6.4)%(P<0.05),伊乐藻水体TN浓度分别降低了(74.1±1.3)%(P<0.01)(41.9±9.5)%(P>0.05)(52.6%±5.6)%(P<0.05)。A组、B组和C组苦草沉积物氧化还原电位分别提高了(209.2±11.0)%,(171.7±8.9)%和(-68.3±8.3)%,伊乐藻沉积物氧化还原电位分别提高了(153.6±7.8)%,(-1.1±20.0)%和(-78.6±12.4)%。