幽门螺杆菌研究进展

幽门螺杆菌（Ｈｅｌｉｃｏｂａｃｔｅｒｐｙｌｏｒｉ）是１９８２年Ｗａｒｒｅｎ和Ｍａｒｓｈａｌｌ等人［１］在培养人体胃粘膜活检组织样品时发现的,当时名为幽门弯曲杆菌（Ｃａｍｐｙｌｏｂａｃｔｅｒｐｙｌｏｒｉ）;以后随着各方面研究的深入,Ｇｏｏｄｗｉｎ等［２］１９８９年建立了螺杆菌属（Ｈｅｌｉｃｏｂａｃｔｅｒ）,才将Ｃ．Ｐｙｌｏｒｉ正式命名为Ｈ．ｐｙｌｏｒｉ．Ｈ．ｐｙｌｏｒｉ是人类慢性活动性胃炎（Ｂ型胃炎）及胃,十二指肠溃疡的重要病原菌,并且是肠型胃癌的诱发因素之一．因而,引起世界范围内对Ｈ．ｐｙｌｏｒ…     

SOLUBLE SUGAR COMPOSITION OF POND‐CYPRESS: A POTENTIAL HYDROECOLOGICAL INDICATOR OF GROUND WATER PERTURBATIONS1

ABSTRACT: Pond‐cypress, a deciduous conifer, is a dominant canopy species in depressional wetlands of the southeastern Coastal Plain (SCP). Extensive premature decline and death of pond‐cypress trees in central Florida have been attributed to hydroperiod alterations due to excessive withdrawals of ground water from the Floridan aquifer. One factor identified in the decline process is basal decay, which may be related to the presence of Botryosphaeria rhodina and Fusarium species (nonaggressive, facultative fungal pathogens). These fungi have been cultured from sapwood tissue of declining pond‐cypress associated with ground water mining, but not from pond‐cypress away from ground water mimng areas. In this experiment, differences in soluble (nonstructural) carbohydrate composition of branch tips were evaluated for one‐and two‐year old, nursery‐grown (unsheltered) pond‐cypress, following a year of growth under treatment conditions (control, fungal inoculation, water stress, and fungal inoculation plus water stress) in a growth chamber. Results from two methods of wet chemical analysis were compared (trimethylsilyl methylglycoside‐Method A, and alditol acetate ‐ Method B). Three pentoses (arabinose, rhamnose, and xylose) and three hexoses (galactose, glucose, and mannose) were identified in branch tips from both age classes. A fourth hexose (fucose) also was identified in samples from the younger trees. The acidic sugar, galacturonic acid, was identified in both age classes using Method A. Results suggest that prolonged water stress is correlated with greater relative concentrations of the neutral soluble sugars rhamnose (P = 0.02), xylose (P = 0.02), and galactose (P = 0.02), in addition to the acidic sugar galacturonic acid (P = 0.01), for Method A, and arabinose (P = 0.02) for Method B. These results also suggest that in the absence of water stress, the fungal pathogen B. rhodina does not penetrate to the sapwood of the trees, and that inoculation with this fungal pathogen is not correlated with differences in relative concentrations of nonstructural, soluble carbohydrates, based on Method A analysis. Empirical evidence suggests that pond‐cypress trees in depressional wetlands respond similarly to anthropogenic perturbations of ground water, but not to natural periods of drought in the absence of such perturbations. Therefore, pond‐cypress appear to be integrators of groundwater perturbations. Greater concentrations of the soluble sugars identified in this study in pond‐cypress branch tips may be hydroecological indicators of such anthropogenic perturbations as unsustainable yield from the regional aquifer and adverse impacts from aquifer storage and recovery (ASR) activities in the SCP.     

碳中和植物降污固碳及其机制研究进展

在经济发展和生态承载的双重制约下,我国实现碳中和碳达峰需要探索更多的技术手段.植物是构建陆地和海洋碳汇体系的重要载体,同时植物修复技术也是治理环境污染的一种科学手段.然而,目前的研究大多集中在植物降污（包括降低环境介质中的污染物浓度和降解污染物两个方面）或植物固碳单一方面,而没有考虑植物降污固碳的双重效益.为挖掘植物的碳中和效应,从碳中和植物入手,深入阐述碳中和植物的降污固碳效应及其进展,评估碳中和植物与其他生物（比如动物、土壤微生物）以及环境功能材料的降污固碳潜力,并对碳中和植物与动物、微生物以及环境功能材料与生态系统协同耦合降污固碳效应的机制进行探究.最后,对碳中和植物降污固碳效应的未来研究方向提出了建设性的展望.     

一体化A_mO_n工艺BP神经网络数学模型研究

讨论基于BP神经网络一体化AmOn污水处理工艺数学模型的构建。在分析神经网络和一体化AmOn污水处理工艺各自特点的基础上,建立了具有11个输入层节点、5个输出层节点以及包含两层隐含层的BP神经网络,并确定了各隐含层的节点数、网络的权值和阈值。对模型的验证结果表明:BP神经网络模型基本反映了AmOn一体化工艺的主要特点,网络预测出水结果与实测结果相差不大,神经网络模型具有较好的泛化能力。     

表面活性剂对中性氧化铝吸附甲基对硫磷的影响

分别应用离子型表面活性剂十二烷基硫酸钠(SDS)、十二烷基苯磺酸钠(SDBS)和十六烷基三甲基溴化铵(CTMAB)改性中性氧化铝对甲基对硫磷这种疏水性环境污染物进行吸附性能研究.结果表明,中性氧化铝对甲基对硫磷的吸附行为与表面活性剂的种类和浓度及环境中pH值有关.原中性氧化铝对甲基对硫磷的吸附能力较小,加入阴离子表面活性剂及调节pH值后其吸附能力增强.氧化铝对3种离子型表面活性剂的吸附性能有所不同,在中性条件下,对SDS的吸附量最大,对CTMAB的吸附量最小;当介质pH为4时,氧化铝对SDS或SDBS的吸附量都有所增大,对CTMAB的吸附量则下降.甲基对硫磷和阴离子表面活性剂同时存在于溶液中时,产生协同效应,使氧化铝对甲基对硫磷的吸附能力有所提高.而阳离子表面活性剂存在下,氧化铝对甲基对硫磷的吸附能力则逐渐下降.     

Damage-inducibility of primary and secondary metabolites in the wild parsnip (Pastinaca sativa)

Summary. Induction of secondary metabolites to herbivore damage is a widespread phenomenon among plants and serves to enhance resistance by reducing suitability or increasing toxicity of foliage. Post-damage responses of primary metabolites are less well known; reductions in primary metabolites may increase resistance by decreasing palatability or nutritional suitability for herbivores or by potentiating toxicity of secondary metabolites. In this study, we examined response to simulated herbivory in Pastinaca sativa, the wild parsnip, in both primary and secondary metabolites. We found that induction of secondary metabolites in response to damage is largely restricted to a single class of compounds, the furanocoumarins. These prooxidant compounds are known to be toxic to a wide variety of insect herbivores. The only primary metabolite that responded to damage was total soluble protein, which increased significantly 24 h after damage. After 24 h, the correlation between total furanocoumarins and total sugars was significant and negative (r = − 0.697). This correlation likely reflects an independent response of sugar to damage, rather than a diversion of resources into furanocoumarin production, inasmuch as this correlation at 3 h, after furanocoumarin induction had taken place, was not significant. In other secondary metabolite pathways, damage produced a significant decline in farnesene and a C-16 unsaturated fatty acid, 7,10,13-hexadecatrienoic acid, each of which may potentiate the furanocoumarin defense response. Farnesene may enhance photooxidative activation of the furanocoumarins and 7,10,13-hexadecatrienoic acid may serve as a precursor to jasmonic acid, a key hormone in regulating induction responses. With few key exceptions, quantities of both primary and secondary metabolites in wild parsnip foliage are unaffected by damage. Those that are affected may well play a role in resistance of parsnips to herbivores. Received 1 July 1998; accepted 28 September 1998.     

中酸性土壤无机磷形态及生物有效性

在黄棕壤和棕红壤上施用磷肥,经三年室内湿润条件下培养,用石灰性土壤无机磷分级方法测定各形态磷含量.各形态用增量的分配比例表明,Fe-P居首位,其次为Al-P和O-P.三级Ca-P之和在20％以下.经培养的土壤种植黑麦草,其生物量和吸磷量与各形态磷量的相关系数除Ca10-P外,均达到极显著水准.土壤有效磷与各形态磷的相关性表明,Ca2-P是土壤有效磷的直接给源（r=0.992）,Fe-P、Al-P是有效磷的重要潜在性给源（r分别为0.982和0.914）,O-P、Ca10-P为无效态磷（r=-0.168）.     

两室中性膜电解过程中铁离子的沉积特性研究

以亚硫酸钠和亚硫酸氢钠溶液模拟钠碱烟气脱硫吸收富液,应用二室中性膜电解装置,对铁离子在阴极板的沉积现象与沉积规律进行研究,确定了沉积物组成成分与铁离子沉积机理,明确了铁离子沉积与膜电解操作参数间的相互关系,结果表明阴极板沉积物中的铁离子主要为硫化亚铁,铁离子沉积量随膜电解电压和硫碱比r增大而明显增大;此外,膜电解过程中随着铁离子沉积于膜表面和阴极板表面的沉积量增加,阴极室压降由于阴极板结垢而降低,膜阻由于模孔堵塞而增大。     

论低压系统检修安全四极开关的设置

在停电检修电器设备时,只断开三根相线（火线）而不断开中性线（零线）,常常因中性线上带有危险故障电压引起事故。因此,四极开关是满足电气检修安全需要的隔离设备,是防止电器部分检修时发生电气事故的有效措施,它应符合电气隔离规定的爬电距离、空气间隙、绝缘水平等要求。     

基于改进型灰色神经网络组合模型的空气质量预测

基于空气质量数据不足及波动较大的情况,将灰色GM（1,1）模型与人工神经网络模型组合并改进,建立改进型灰色神经网络组合模型。利用天津市2001—2008年PM10、SO2和NO2年均值作为原始数据预测2009—2010年PM10、SO2和NO2的浓度以进行模型精度检验,最后利用该模型预测2011—2015年天津市空气质量状况。结果表明,与灰色GM（1,1）模型、传统灰色神经网络组合模型相比,所建立的改进型灰色神经网络组合模型相对模拟误差小,预测结果更为可靠,可以用于空气质量预测。