部分苯衍生物对黄瓜种子发芽率的抑制毒性及QSAR研究

采用半静态培养法测定了29种苯衍生物对黄瓜种子发芽率的48h抑制毒性,并进行了定量结构-活性相关研究．结果表明：苯衍生物对黄瓜种子发芽率的抑制毒性不仅与化合物的疏水性(lgKOW)有关,而且与其分子最低未占轨道能量(ELUMO)有关．     

SO2衍生物对C57BL/6小鼠肝脏T细胞亚群CD4+/CD8+的影响

为探讨二氧化硫(SO2)的肝脏免疫毒理效应,利用流式细胞仪(FACS)检测技术,分析了SO2体内代谢衍生物——亚硫酸钠(Na2SO3)与亚硫酸氢钠(NaHSO3)混合液(两者摩尔比为3:1)腹腔注射染毒对C57BL/6小鼠肝脏淋巴细胞T细胞亚群CD4+和CD8+的百分数以及CD4+/CD8+细胞比值的影响.实验组剂量分别为25、100、400mg·kg-1(body weight),染毒一周后,制备肝脏淋巴细胞悬液,经特异性荧光标记的CD4(FITC)、CD8(PE)单克隆抗体染色后,采用FACS流式细胞仪检测T淋巴细胞亚群百分数.研究发现:1)染毒后所有处理组肝脏CD4+T细胞所占的百分数显著升高(p<0.05);2)CD8+T细胞所占的百分数在100mg·kg-1、400mg·kg-1染毒组显著降低(p<0.05);3)CD4+/CD8+的比值在100mg·kg-1、400mg·kg-1染毒组显著升高(p<0.01).研究结果显示:SO2体内衍生物亚硫酸钠和亚硫酸氢钠可使肝脏CD4+/CD8+T细胞的比值显著升高,即SO2衍生物可使肝脏CD4和CD8淋巴细胞比例严重失调而使机体产生免疫紊乱.     

Biogas from the organic fraction of municipal solid waste: Dealing with contaminants for a solid oxide fuel cell energy generator

The present work investigates electricity production using a high efficiency electrochemical generator that employs as fuel a biogas from the dry anaerobic digestion of the organic fraction of municipal solid waste (OFMSW).The as-produced biogas contains several contaminants (sulfur, halogen, organic silicon and aromatic compounds) that can be harmful for the fuel cell: these were monitored via an innovative mass spectrometry technique that enables for in-line and real-time quantification.A cleaning trap with activated carbons for the removal of sulfur and other VOCs contained in the biogas was also tested and monitored by observing the different breakthrough times of studied contaminants.The electrochemical generator was a commercial Ni anode-supported planar Solid Oxide Fuel Cell (SOFC), tested for more than 300 h with a simulated biogas mixture (CH₄ 60 vol.%, CO₂ 40 vol.%), directly fed to the anode electrode. Air was added to promote the direct internal conversion of CH₄ to H₂ and CO via partial oxidation (POx).The initial breakthrough of H₂S from the cleaning section was also simulated and tested by adding ～1 ppm(v) of sulfur in the anode feed; a full recovery of the fuel cell performance after 24 h of sulfur exposure (～1 ppm(v)) was observed upon its removal, indicating the reliable time of anode exposure to sulfur in case of exhausted guard bed.     

Effect of an eco-friendly o/w emulsion stabilized with amphiphilic sodium alginate derivatives on lambda-cyhalothrin adsorption–desorption on natural soil minerals

The effects of amphiphilic O/W emulsions,stabilized by the alkyl polyglycoside(APG)or cholesterol-grafted sodium alginate(CSAD)/APG systems,on lambda-cyhalothrin adsorption/desorption mechanisms on natural soil minerals(i.e.,illite and kaolinite)were investigated.Sorption and desorption of lambda-cyhalothrin onto soil minerals was studied via batch equilibration to give insight into the adsorption equilibrium,kinetics,and thermodynamics of lambda-cyhalothrin adsorption onto minerals.The results indicate the following:(i)The adsorption processes for the APG system and CSAD/APG system include:rapid adsorption,slow adsorption,and adsorption equilibrium.The adsorption kinetics of pesticide on illite and kaolinite are in accordance with the Ho and McKay model,and the adsorption isotherm conforms to the Freundlich model.In addition,the adsorption processes of pesticide for the two systems on minerals were spontaneous and feasible(ΔG~00),endothermic(ΔH~00),and mainly involved chemical bonding(ΔH~060).(ii)The equilibrium adsorption percentages of the pesticide on illite for the APG system and CSAD/APG system were 42.4%and 64.8%,and the corresponding equilibrium adsorption percentages on kaolinite were 40.8%and 61.8%,respectively.Moreover,the pesticide adsorption rate K_(2-CSAD/APG)was faster than K_(2-APG),and its adsorption capacity K_(f-CSAD/APG )was greater than K_(f-APG).Meanwhile,the pesticide desorption K_(fd)in the CSAD/APG system was smaller than that in the APG system.As a result,this eco-friendly O/W emulsion based on amphiphilic sodium alginate derivatives might provide a green pesticide formulation,since it could reduce the amount of lambda-cyhalothrin entering aquatic systems to threaten non-target fish and invertebrate species.     

杯[4]芳烃及其酯类衍生物对贵金属离子银的回收研究

应用对叔丁基杯[4]芳烃及其酯类衍生物对液相中的银离子进行回收,讨论了在不同pH值条件下回收液相中的银离子。在去除有机溶剂正辛烷对回收的影响后,发现对叔丁基杯[4]芳烃及其酯类衍生物在强酸性条件下对银离子均有一定的萃取能力,且对叔丁基杯[4]芳烃乙酸乙酯对银离子的萃取能力明显要高于对叔丁基杯[4]芳烃。反萃取剂选用硫代硫酸钠,但其反萃取效率随着原液酸性的增强而减少,且对酯类体系几乎无反萃取效果。     

Photodegradation of new amino acid derivatives suitable for chelating agents in pulp bleaching applications

The purpose of this study was to evaluate photodegradabilities of the following new low-nitrogen chelating agents: N-bis[(carboxymethoxy)ethyl]glycine (compound 1), N-bis[(1,2-dicarboxyethoxy)ethyl]glycine (compound 2) and N-bis[(1,2-dicarboxyethoxy)ethyl]aspartic acid (compound 3). At first photodegradation of these chelating agents as uncomplexed Na-compound 1–3 and Cu(II) complexes were tested, both in lake and distilled water, by exposing them to near-UV region radiation at the range of 315–400 nm. Uncomplexed Na-compounds 2 and 3 were selected to sunlight exposure experiments carried out in lake and distilled water. Compound 3 was also tested in sunlight as Cu and Ca complexes in both solutions. Photodegradation of Na₆-compound 3 in distilled water was studied by exposing it to radiation at the wavelength of 253.7 nm. Photodegradation products were analysed by means of GC-MS (gas chromatography with mass selective detector).

The results demonstrated that compound 1 was quite photostable even as Cu complex while compounds 2 and 3 were found to be photodegradable. Over 90% reduction of compound 3 was achieved during one week and 80% reduction of compound 2 in two weeks' time when they were added as Na salt to lake water and exposed to sunlight. Compound 3 as Cu complex degraded totally in the sunlight in less than one week. In the case of compound 3, the degradation rate decreased depending on the counter cation in the order Cu > Na  Ca. The study demonstrated that photodegradation of Na₆-compound 3 does not result in total mineralization of the compound. A photodegradation pathway for Na₆-compound 3 is proposed.     

Hydrogeomorphic considerations in development planning and stormwater management,central Texas Hill Country,USA

Watershed ordinances in Austin, Texas, USA, are intended to protect streams from stormwater degradation. Their adequacy is being questioned, however, where development is advancing into the Hill Country northwest and southwest of the city. Detailed investigation into hillslope runoff reveals that several important facts were overlooked in the ordinances, including locally high infiltration rates and drainage basins, which function as partial area systems. As a result, development planning is not taking advantage of the natural mitigation potential of the land. Roads cut across infiltration and moisture retention areas on side slopes, enlarging the partial area system feeding streams with stormflows. In addition, most residential planning is not responsive to the stepped microtopography of Hill Country drainage basins and the critical scale at which local runoff processes operate. Recommendations include adjusting the scale and configuration of development to conform with local runoff processes and features and taking advantage of the water-absorbing capacities of basin side slopes. The lesson for ordinance writers is that standard models of community stormwater ordinances are not appropriate for all terrains, especially complex ones like the Texas Hill Country.     

Synthesis of some novel (2-oxo-3-(arylimino) indolin-1-yl)-N-aryl acetamides and evaluation as antimicrobial agents

A series of sixteen 2-oxo-3-(arylimino) indolin-1-yl)-N-aryl acetamide derivatives were synthesized, characterized by physical and spectral data (IR, ¹H nuclear magnetic resonance (NMR), and mass spectrometry), and evaluated for their antibacterial and antifungal activities against various pathogenic microorganisms. Some of the synthesized compounds showed promising antibacterial and antifungal activities, the best being 2-(3-(4-chlorophenylimino)-2-oxoindolin-1-yl)-N-(3-methoxyphenyl) acetamide.     

Resolving structural uncertainty in natural resources management using POMDP approaches

In recent years there has been a growing focus on the uncertainties of natural resources management, and the importance of accounting for uncertainty in assessing management effectiveness. This paper focuses on uncertainty in resource management in terms of discrete-state Markov decision processes (MDP) under structural uncertainty and partial observability. It describes the treatment of structural uncertainty with approaches developed for partially observable resource systems. In particular, I show how value iteration for partially observable MDPs (POMDP) can be extended to structurally uncertain MDPs. A key difference between these process classes is that structurally uncertain MDPs require the tracking of system state as well as a probability structure for the structure uncertainty, whereas with POMDPs require only a probability structure for the observation uncertainty. The added complexity of the optimization problem under structural uncertainty is compensated by reduced dimensionality in the search for optimal strategy. A solution algorithm for structurally uncertain processes is outlined for a simple example in conservation biology. By building on the conceptual framework developed for POMDPs, natural resource analysts and decision makers who confront structural uncertainties in natural resources can take advantage of the rapid growth in POMDP methods and approaches, and thereby produce better conservation strategies over a larger class of resource problems.     

Correlations of Eisenia fetida metabolic responses to extractable phenanthrene concentrations through time

Eisenia fetida earthworms were exposed to phenanthrene for thirty days to compare hydroxypropyl-β-cyclodextrin (HPCD) extraction of soil and ¹H NMR earthworm metabolomics as indicators of bioavailability. The phenanthrene 28-d LC₅₀ value was 750 mg/kg (632-891, 95% confidence intervals) for the peat soil tested. The initial phenanthrene concentration was 319 mg/kg, which biodegraded to 16 mg/kg within 15 days, at which time HPCD extraction suggested that phenanthrene was no longer bioavailable. Multivariate statistical analysis of ¹H NMR spectra for E. fetida tissue extracts indicated that phenanthrene exposed and control earthworms differed throughout the 30 day experiment despite the low phenanthrene concentrations present after 15 days. This metabolic response was better correlated to total phenanthrene concentrations (Q² = 0.59) than HPCD-extractable phenanthrene concentrations (Q² = 0.46) suggesting that ¹H NMR metabolomics offers considerable promise as a novel, molecular-level method to directly monitor the bioavailability of contaminants to earthworms in the environment.