Adsorption of branched alkylbenzene sulfonate onto styrene and acrylic ester resins

In this study, a series of acrylic ester resins were prepared and characterized. The adsorption behaviors of sodium 6-dodecyl benzenesulfonate (6-NaDBS) on styrene resin XAD-4 and acrylic ester resins have been studied. As compared to commercial acrylic ester resins Amberlite XAD-7 and Diaion HP2MG, YWB-38, one of the as-prepared resins, exhibits better adsorption properties toward 6-NaDBS. The experimental equilibrium data were fitted to the Langmuir and double-Langmuir models. The two models provide very good fit for all acrylic ester resins over the temperature range studied, whereas fitted results for styrene resin XAD-4 are less accurate. The investigation indicates that the adsorbate molecules are directly adsorbed on acrylic ester resins as a bi-layer, while the molecules are adsorbed on XAD-4 as monolayer formation followed by the establishment of bi-layer. Adsorption kinetics and elution processes were also investigated for further exploring the adsorption behavior and mechanism on styrene resin XAD-4 and YWB-38.     

电袋复合除尘器中产生氧化性物质的研究

针对电袋复合除尘器前级电场电晕放电有可能会产生臭氧,而臭氧又迅速与烟气中NO反应生成NO2这一猜想,通过对实际工况下电袋复合除尘器中臭氧含量和NOX浓度进行的测试,得出电袋复合除尘器中并无臭氧产生,且NO2浓度也未增加。但烟气中NO2浓度已经接近除尘器PPS滤料在使用温度下(150℃)所能承受的最高限值,PPS滤料会因发生氧化而失效,缩短滤料使用寿命。     

某市区重点行业职业病危害因素现状调查研究

对某市区重点行业15家企业职业病危害因素进行检测与评价,对普查结果进行综合分析。结果表明:15家企业工作场所化学有害因素职业卫生现状情况良好,但噪声危害程度较大;在6个重点行业中,电子制造行业有害因素合格率最低,为84%,其次是纺织行业,有害因素合格率为85%,其他化学原料及化学制品、化工、木制家具、石材加工四个行业合格率均较高;市直以上企业职业卫生现状情况优于区属企业,300-2000人之间较大规模的企业职业卫生现状情况优于300人以下的企业。同时,对企业提出了职业危害现状的改进措施与建议。     

中美民航安全管理比较

从发展历程、管理组织、行政执法、安全信息收集与利用等方面,对中美民航安全管理进行了比较,发现:同美国相比,我国民航安全管理起步较晚;作为我国民航安全管理主体的中国民用航空局,在机构体系和管理模式上成功的借鉴了美国联邦航空局的经验,但各部门职能存在交叉或真空现象;执法环境相对落后;安全信息资源利用率较低。在此基础上,提出了进一步完善我国民航安全管理的建议:加大民航相关部门合作力度;加强民航安全文化塑造;加快民航安全信息资源共享体系建设等。     

微囊藻毒素-LR对鸡肝脏的氧化损伤影响

蓝藻虽然能产生有毒的生物毒素,但是也含有较高的蛋白质。为探索蓝藻饲料化利用的可能性,本文通过腹腔注射的方式研究了微囊藻毒素-LR(MC-LR)对崇仁麻鸡的半数致死剂量(LD_(50))及其对肝脏的氧化损伤。实验设计了4个剂量组(对照组、5、10和20μg·kg~(-1)MC-LR),并在1、3、12、24和48 h检测了谷胱甘肽(GSH)含量以及谷胱甘肽S-转移酶(GST)、谷胱甘肽过氧化物酶(GPX)、超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性变化。结果表明,MC-LR对崇仁麻鸡的LD_(50)值为34.67μg·kg~(-1)体重(bw),95%的置信限为33.51～35.83μg·kg~(-1)bw。在MC-LR的作用下,鸡肝出现了氧化应激现象。3个染毒组鸡肝中GSH含量呈现先下降而后上升恢复至正常水平的趋势,GST酶活力表现为先上升而后下降至正常值的趋势,这说明GSH和GST共同参与了鸡肝中MC-LR的解毒;鸡肝中GPX酶活性在前3小时先保持不变(除了1 h的高剂量组),随即显著上升,这说明GPX和GSH共同参与了鸡肝中过量活性氧自由基(ROS)的清除,GPX可以作为监测MC-LR引起鸡毒性作用的生物标志物。CAT酶活力表现为先显著下降(P<0.05)而后快速上升至正常值的趋势,SOD酶在整个实验期间几乎保持稳定,这可能与SOD酶活性较高所致。     

Implications of genetics and current protected areas for conservation of 5 endangered primates in China

Most of China's 24–28 primate species are threatened with extinction. Habitat reduction and fragmentation are perhaps the greatest threats. We used published data from a conservation genetics study of 5 endangered primates in China (Rhinopithecus roxellana, R. bieti, R. brelichi, Trachypithecus francoisi, and T. leucocephalus); distribution data on these species; and the distribution, area, and location of protected areas to inform conservation strategies for these primates. All 5 species were separated into subpopulations with unique genetic components. Gene flow appeared to be strongly impeded by agricultural land, meadows used for grazing, highways, and humans dwellings. Most species declined severely or diverged concurrently as human population and crop land cover increased. Nature reserves were not evenly distributed across subpopulations with unique genetic backgrounds. Certain small subpopulations were severely fragmented and had higher extinction risk than others. Primate mobility is limited and their genetic structure is strong and susceptible to substantial loss of diversity due to local extinction. Thus, to maximize preservation of genetic diversity in all these primate species, our results suggest protection is required for all sub‐populations. Key priorities for their conservation include maintaining R. roxellana in Shennongjia national reserve, subpopulations S4 and S5 of R. bieti and of R. brelichi in Fanjingshan national reserve, subpopulation CGX of T. francoisi in central Guangxi Province, and all 3 T. leucocephalus sub‐populations in central Guangxi Province.     

瓦斯压力对卸荷原煤力学特性及能量特征的影响

运用自主研制的含瓦斯煤热流固耦合三轴伺服渗流试验装置,以原煤煤样作为研究对象,进行了含瓦斯煤固定轴向压力、卸围压的渗流试验,研究了卸围压过程中瓦斯压力对煤样力学特性和能量特征的影响。结果表明:在轴压加载阶段,煤样的变形模量基本不变,泊松比逐渐减小;在定轴压卸围压阶段,煤样的变形模量先小幅度增加,然后逐渐减小,泊松比则逐渐增大。瓦斯压力越高,煤样的承载能力越低,煤样发生破坏时相应的轴向应变和围压卸荷量百分比越小,而煤样破坏时的径向变形和扩容量越大。各应变围压柔量Δεi与瓦斯压力呈线性关系且线性相关性良好。随瓦斯压力升高,轴向应变的围压敏感性降低,径向应变和体积应变的围压敏感性显著升高。随瓦斯压力升高,煤样发生破坏时存储的弹性应变能Ue减小,而总能量U、耗散能Ud和耗散能比例Ud/U都增大。     

Kinetic analysis of anaerobic phosphorus release during biological phosphorus removal process

Enhanced biological phosphorus removal (EBPR) is a commonly used and sustainable method for phosphorus removal from wastewater. Poly-β-hydroxybutyrate (PHB), polyphosphate, and glycogen are three kinds of intracellular storage polymers in phosphorus accumulation organisms. The variation of these polymers under different conditions has an apparent influence on anaerobic phosphorus release, which is very important for controlling the performance of EBPR. To obtain the mechanism and kinetic character of anaerobic phosphorus release, a series of batch experiments were performed using the excessively aerated sludge from the aerobic unit of the biological phosphorus removal system in this study. The results showed that the volatile suspended solid (VSS) had an increasing trend, while the mixed liquid suspended sludge (MLSS) and ashes were reduced during the anaerobic phosphorus release process. The interruption of anaerobic HAc-uptake and phosphorus-release occurs when the glycogen in the phosphorus-accumulating-organisms is exhausted. Under the condition of lower initial HAc-COD, HAc became the limiting factor after some time for anaerobic HAc uptake. Under the condition of higher initial HAc-COD, HAc uptake was stopped because of the depletion of glycogen in the microorganisms. The mean ratio of Δρ _P/Δρ _PHB, Δρ _GLY/Δρ _PHB, Δρ _P/ΔCOD, was 0.48, 0.50, 0.44, and 0.92, respectively, which was nearly the same as the theoretical value. The calibrated kinetic parameters of the HAc-uptake and phosphorus-release model were evaluated as follows: Q _HAc,max was 164 mg/(g · h), Q _P,max was 69.9 mg/(g · h), K _gly was 0.005, and KCOD was 3 mg/L. An apparently linear correlation was observed between the ratio of Δρ _P/ΔCOD and pH of the solution, and the equation between them was obtained in this study.     

Distribution of quinolone and macrolide resistance genes and their co-occurrence with heavy metal resistance genes in vegetable soils with long-term application of manure

The spread of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) has become an increasingly serious global public health issue. This study investigated the distribution characteristics and influencing factors of ARB and ARGs in greenhouse vegetable soils with long-term application of manure. Five typical ARGs, four heavy metal resistance genes (MRGs), and two mobile genetic elements (MGEs) were quantified by real-time quantitative polymerase chain reaction (qPCR). The amount of ARB in manure-improved soil greatly exceeded that in control soil, and the bacterial resistance rate decreased significantly with increases in antibiotic concentrations. In addition, the resistance rate of ARB to enrofloxacin (ENR) was lower than that of tylosin (TYL). Real-time qPCR results showed that long-term application of manure enhanced the relative abundance of ARGs in vegetable soils, and the content and proportion of quinolone resistance genes were higher than those of macrolide resistance genes. Redundancy analysis (RDA) showed that qepA and qnrS significantly correlated with total and available amounts of Cu and Zn, highlighting that certain heavy metals can influence persistence of ARGs. Integrase gene intI1 correlated significantly with the relative abundance of qepA, qnrS, and ermF, suggesting that intI1 played an important role in the horizontal transfer of ARGs. Furthermore, there was a weakly but not significantly positive correlation between specific detected MRGs and ARGs and MGEs. The results of this study enhance understanding the potential for increasing ARGs in manure-applied soil, assessing ecological risk and reducing the spread of ARGs.

Graphic abstract

     

Scenarios of major terrestrial ecosystems in China

The spatial pattern and mean-center shift of major terrestrial ecosystems, termed Holdridge Life Zones (HLZ), during the periods from 1961 to 1990 (T1), from 2010 to 2039 (T2), from 2040 to 2069 (T3) and from 2070 to 2099 (T4) were analyzed by combining the zonal patterns of climatic change in China and the climatic change scenarios of HadCM2 and HadCM3. The results showed that nival area would decrease rapidly with temperature increase in the future. HadCM2 and HadCM3 predicted that the nival areas might disappear in 552 years and 204 years, respectively. Using both HadCM2 and HadCM3, the five HLZ types with the largest areal extent are nival zone, cool temperate moist forest, warm temperate moist forest, subtropical moist forest and boreal wet forest, which collectively account for more than 50% of China's land mass. Among these five HLZ types, nival zone, warm temperate moist forest and boreal wet forest would decrease continuously, whereas subtropical moist forest and cool temperate forest would increase continuously during the four periods. HLZ diversity and patch connectivity would increase continuously in the 21st century. The shift distances of mean centers of HLZ types simulated using HadCM3 were markedly greater than those simulated using HadCM2, in general. The results from both HadCM2 and HadCM3 showed that boreal wet forest, subtropical moist forest, tropical dry forest, warm temperate moist forest and subtropical wet forest had bigger shift ranges, indicating that these HLZ types are more sensitive to the climatic change scenarios of HadCM2 and HadCM3.