进气压力和EGR对柴油掺混PODEn燃烧的影响

对柴油掺混聚甲氧基二甲醚(PODEn)双燃料发动机的燃料特性进行了研究.探讨了进气压力和EGR对柴油掺混聚甲氧基二甲醚燃烧和排放的影响.结果表明:随着进气压力的提高,发动机燃烧相位提前,动力性和经济性明显提高,但NOX排放物随着进气压力的提高持续增加,Soot排放物呈现出先上升后下降的趋势.随着EGR率的提高,发动机燃...     

二甲基二碳酸盐对荔枝汁的杀菌效果 及其耐受菌的分离鉴定

研究了处理温度和时间对二甲基二碳酸盐（DMDC）在新鲜荔枝汁中杀菌效果的影响,并测定了新鲜荔 枝汁经DMDC 处理后在4益贮藏期间微生物的动态变化。结果发现,提高温度能提高DMDC 的杀菌速率,缩短杀菌 时间,但不能提高总的杀菌效果。4益的荔枝汁添加DMDC 12 h后,酵母菌已经被完全杀灭,菌落总数、乳酸菌数和霉 菌数分别降低至3.73、2.6 和0.3 个对数。DMDC 处理后残留的污染菌采用16S 或18S rDNA 法进行鉴定后发现其主 要是芽孢杆菌属、毛霉属和明串珠菌属菌株,其中明串珠菌属是优势菌群。DMDC 处理后的荔枝汁在4益贮藏期间, 残留的明串珠菌能表现出生长,贮藏40 d后,其菌数将达到5个对数以上,会对荔枝汁的营养和风味产生影响。     

Cytotoxicity of Senecio in macrophages is mediated via its induction of oxidative stress

In Arunachal Pradesh and other sub-Himalayan areas of India, accidental consumption of Senecio plants by yaks is often fatal as the plant contains toxic alkaloids like Seneciophylline. The present investigation was undertaken to demonstrate the pro-oxidant effects of an ethanolic extract of Seneciochrysanthemoides (S-EtOH). S-EtOH impaired viability in macrophages, the IC₅₀ being 13.8 ± 1.11 μg/mL. The effect of S-EtOH (1 μg/mL) on generation of reactive oxygen species (ROS) in macrophages was measured by flow cytometry using 2′,7′-dichlorofluorescein diacetate (H₂DCFDA) where it caused a significant increase in the mean fluorescence channel (MFC) from 8.55 ± 0.03 to 47.32 ± 2.25 (p < 0.001). S-EtOH also effected a 3.8-fold increase in extracellular nitric oxide (NO) generation from 4.90 ± 0.72 μM to 18.79 ± 0.32 μM (p < 0.001), a 2.2-fold increase in intracellular NO production, the MFC increasing from 14.95 ± 0.48 to 33.34 ± 1.66 (p < 0.001), and concomitantly depleted non protein thiols as analyzed by flow cytometry using mercury orange, with a reduction in MFC from 632.5 ± 49.44 to 407.4 ± 12.61 (p < 0.01). Additionally, S-EtOH (14 μg/mL, 24 h) caused apoptosis as evident by increased Annexin V binding and terminal deoxynucleotidyl transferase mediated dUTP DNA nick end labeling. Taken together, the cytotoxicity of S-EtOH can be partly attributed to its capacity to inflict oxidative damage via generation of both reactive oxygen and nitrogen species culminating in apoptosis.     

高效液相色谱法测定蔬菜中邻苯二甲酸二丁酯残留

用高效液相色谱法测定了蔬菜中的邻苯二甲酸二丁酯残留含量。实验色谱条件为色谱柱:ZOR-BAX SB-C18 4.6 mm×150 mm,5μm;温度:室温(25℃);检测器:紫外检测器;检测波长:224 nm;进样量:10μl;流速:1.0 ml/min。检测方法在2～50μg/ml呈线性,最低检出限(3/n)0.025μg/ml,相关系数0.9991。蔬菜中邻苯二甲酸二丁酯含量0.45～7.70 mg/kg。实验表明邻苯二甲酸二丁酯在所检测的蔬菜中均有残留,可能与种植土壤污染有关。     

Chemical induction of apomictic seed formation in maize

Summary Silks of 18 maize (Zea may L.) F₁ hybrids were treated with different combinations of 9 growth regulators, colchicine, and dimethyl sulfoxide (DMSO) for the purpose to induce apomixis (agamospermy) in 1988 and 1989. Hybrid K301 × K303 gave the highest (0.36%) average frequency of seed induction among the hybrids. The most effective treatments were DMSO, gibberellic acid plus 6-benzyl aminopurine (6-BA), and DMSO plus methanesulfonic acid. Individually, the highest frequency of seed induction was 1.4% for hybrid K731×K306 when treated with -naphthalene acetic acid (NAA)-zeatin mixture. The frequency of seed induction seemed to depend partially on the interaction between chemicals and hybrids. Cytological observation of root-tip cells indicated that the majority of the seeds obtained were diploid, some were mixoploid, and a few were haploid. Diploid plants from induced seeds from the same parent were morphologically uniform and resembled the parent. Variations in plant and ear heights were comparable to those of the hybrid parent. Cytological and morphological investigations suggested that the chemically induced seeds originated mainly from somatic tissue but occasionally came from reduced cells in the embryo sac, leading to haploids. The results showed that chemical induction of adventitious embryony in maize hybrids is possible, but the more effective chemicals, their concentrations, and ways of application for increasing the frequency of seed induction need to be explored for practical use.     

二甲醚/柴油混合燃料在柴油机上应用

在柴油机上进行了燃用不同比例的二甲醚/柴油混合燃料的试验研究,结果表明,燃油系统不做改动的情况下,燃用二甲醚与柴油混合燃料时,随二甲醚掺烧比例的增加,NOx和碳烟排放均下降,CO和HC排放性能也有所改善,动力性和经济性与原机无明显差异,对改善柴油机的排放有着重要的作用.     

DBP与DBAA低剂量联合作用对雄性大鼠生殖功能的影响

目的探讨邻苯二甲酸二丁酯（DBP）与溴乙酸（DBAA）联合作用对雄性大鼠睾丸功能影响．方法将28只6周龄清洁级雄性Sprague—Dawley大鼠随机分为阴性对照组（玉米油）、DBP组（DBP250mg／kg，1／32LD50）、DBAA组（DBAAl25mg／kg，1／32LD50）、联合组（DBP250mg／kg＋DBAA125mr,／kg）；灌胃量为10mL／kg体质量，1次／d，连续灌胃5周；对睾丸脏器系数、附睾脏器系数及精子质量进行检测．结果DBP和DBAA联合组的睾丸、附睾脏器系数与对照组比较均下降（P〈0．05）；DBP和DBAA联合组的精子密度、精子活率与对照组比较均下降（P〈0．05）；各组精子畸形率分别与对照组比较均升高（P〈0．05）．析因分析结果显示：DBP和DBAA可致大鼠脏器系数降低及精子畸形率升高，并存在交互作用．结论DBP和DBAA均能影响大鼠睾丸功能，且DBP与DBAA联合损伤作用更强，表现为协同损伤作用．     

Dose-dependent sub-chronic toxicity of diethyl phthalate in female Swiss mice

The experiment was conducted to study the after effects of administering DEP at different doses to female Swiss mice for a period of 90 days. Group I mice were fed on normal diet and water ad libitum. Group II mice were maintained on normal diet mixed with corn oil at 8.25 mg/kg of the diet/day as oil control. Group III, IV and V mice were given diethyl phthalate dissolved in corn oil mixed with the diet at 10, 25 and 50 mg/kg of the diet/day, which is approximately equal to 1.25, 3.125 and 6.25 mg/kg body weight/day. A significant dose dependent increase was observed in serum acid phosphatase (ACP) whereas, serum and liver triglycerides levels showed a significant increase only in the high-dose treated group. Significant dose-dependent increase in serum aspartate and alanine aminotransferase (AST and ALT) and liver glycogen was observed. Serum lactate dehydrogenase (LDH) was significantly increased only in 25 and 50 ppm DEP-treated mice. Liver cholesterol was significantly increased in all the treated groups. Liver histology by light microscopy showed intracellular vacuolations in all the treated groups which was much more evident in the 25 and 50 ppm DEP-treated mice while hepatocellular degeneration and hypertrophy of the hepatocytes was evident in 50 ppm DEP-treated mice. Proliferation of mitochondria and peroxisomes was evident in the electron micrographs of the 10 ppm DEP-treated mice while 25 and 50 ppm DEP-treated mice showed increase in lipid droplets and severe mitochondrial proliferation.     

两种化感物质对茄子生长及幼苗生理特性的影响

采用化感物质2,6-二叔丁基苯酚和邻苯二甲酸二甲酯进行茄子幼苗栽培试验,研究了化感物质对茄子幼苗生长及生理生化特性的影响.结果表明:2,6-二叔丁基苯酚和邻苯二甲酸二甲酯2种化感物质在50~500μmol/L浓度范围内处理茄子幼苗,茄子株高、茎粗、地上地下部干鲜重和根系活力都受到明显的抑制,丙二醛含量及超氧自由基产生速率增大,且随处理浓度的增加和处理时间的延长,抑制作用加强.     

邻苯二甲酸二乙基己酯（DEHP）胁迫下红鳍笛鲷不同组织生化指标的变化

以红鳍笛鲷（Lutjanus erythropterus）幼鱼为实验生物,根据急性毒性实验结果（96hLC50为10.73mg·L-1）设置邻苯二甲酸二乙基己酯（DEHP）的浓度为0.12、0.60、3.00mg·L-（1以丙酮为对照）,在实验进行6、12、24、48h和96h时,分别检测肝脏和鳃组织超氧化物歧化酶（SOD）活性和丙二醛（MDA）含量,以及脑组织乙酰胆碱脂酶（AChE）活性。结果表明,肝脏组织中的SOD反应灵敏且活性明显被诱导,低剂量组（0.12、0.60mg·L-1）SOD活性受到的诱导效应较高剂量组（3.00mg·L-1）更明显;与对照组比较,肝组织中MDA含量在DEHP曝露的12h显著性升高,但48h的MDA含量显著性降低（P〈0.01）,随曝露时间呈波动变化。鳃组织中的SOD活性明显低于肝脏组织,整个过程中表现为先升高后降低的变化规律,其中高剂量组（3.00mg·L-1）受到的诱导最明显;与对照组比较,MDA含量12h后即显著升高（P〈0.01）,随后MDA含量开始下降并围绕对照组水平上下波动。各剂量组脑组织AChE活性仅在6h受到抑制,此后受到明显的诱导作用酶活性升高,24h达到最大值,并显著高于对照组（P〈0.01）,但96h后恢复到对照组水平,呈明显的时间-效应关系。以上结果显示,DEHP对红鳍笛鲷幼鱼组织酶活在实验浓度下影响显著,对水生生物存在危害,应对其生态风险加以关注。