Effect of nitrogen doping on the reduction of nitric oxide with activated carbon in the presence of oxygen

Nitrogen doping of activated carbon （AC） was performed by annealing both in ammonia and nitric oxide, and the activities of the modified carbons for NO reduction were studied in the presence of oxygen. Results show that nitrogen atoms were incorporated into the carbons, mostly in the form of pyridinic nitrogen or pyridonic nitrogen. The effect of nitrogen doping on the activities of the carbons can be ignored when oxygen is absent, but the doped carbons show desirable activities in the low temperature regime （≤500 ℃） when oxygen is present. The role of the surface nitrogen species is suggested to promote the formation of NO2 in the presence of oxygen, and NO2 can facilitate decomposition of the surface oxygen species in the low temperature regime     

Science Letters：Nitrogen doping of activated carbon loading Fe2O3 and activity in carbon-nitric oxide reaction

Nitrogen doping of activated carbon loading Fe2O3 was performed by annealing in ammonia, and the activity of the modified carbon for NO reduction was studied in the presence of oxygen. Results show that Fe2O3 enhances the amount of surface oxygen complexes and facilitates nitrogen incorporation in the carbon, especially in the form of pyridinic nitrogen. The modified carbon shows excellent activity for NO reduction in the low temperature regime (<500 °C) because of the cooperative effect of Fe2O3 and the surface nitrogen species.     

球磨工艺对活性炭孔结构及电化学性能的影响

The effects of particle size of activated carbon （AC） on its wettability, electrode coating technology and electric chemical performance were studied to assemble nonaqueous electric double layer capacitors （EDLCs） for high power requirements. The results show that the specific surface area and total pore volume of AC decrease from 2 137 m^2/g to 1 683 m^2/g, and 0.95 cm^3/g to 0.78 cm^3/g, respectively, if it is ball-milled for 8 h. The pore size distributions are similar in the range of 0.7 nm to 3.5 nm for different ball-milling time. There exists oxidation on the surface of AC during the ball-milling process and the ratios of O-C=O oxygen compositions increase whereas those of C-O, C=O decrease. The peeling strength of AC coated on current collector is almost inverse proportion with the particle size of AC as well as the resistance of EDLCs, and its capacitance decreases about 6%.     

一氧化氮对去卵巢大鼠骨组织形态计量学的影响

目的:观察一氧化氮(NO)供体硝酸异山梨酯(Isosorbride Dinitrate,ID)及一氧化氮合酶(NOS)抑制剂氨基胍(Aminoguanidine,AG)对双侧卵巢切除(OVX)大鼠骨组织形态计量学的影响。方法:49只雌性大鼠随机分成7组,每组7只。①假手术(Sham)组、②卵巢切除(OVX)组、③卵巢切除 雌激素(OVX EB)组、④卵巢切除 NO供体(OVX ID)组、⑤卵巢切除 NO供体和雌激素(OVX ID EB)组、⑥卵巢切除 NOS抑制剂(OVX AG)组、⑦卵巢切除 NOS抑制剂和雌激素(OVX AG EB)组。实验10周后处死大鼠,对第4、5腰椎进行骨组织形态计量学分析。结果:与Sham组相比:OVX组、OVX AG组和OVX AG EB组组织形态计量学参数BV/TV和Tb.Th减少,Tb.Sp和MAR增加(P<0.05);而OVX EB组、OVX ID组和OVX ID EB组骨组织形态计量学参数BV/TV、Tb.Th、Tb.Sp和MAR均无明显差异(P>0.05)。与OVX组相比:OVX EB组、OVX ID组和OVX ID EB组骨组织形态计量学参数BV/TV和Tb.Th明显增加,Tb.Sp和MAR明显减少(P<0.05);而OVX AG组和OVX AG EB组骨组织形态计量学参数BV/TV、Tb.Th、Tb.Sp和MAR均无明显差异(P>0.05)。结论:NO供体预防OVX鼠骨丢失,NOS抑制剂则阻止雌激素预防OVX鼠骨丢失的作用。     

Science Letters:Dechlorination mechanism of 2,4-dichlorophenol by Ni/Fe nanoparticles in the presence of humic acid

To understand the feasibility of its application to the in situ remediation of contaminated groundwater, the dechlori-nation of 2,4-dichlorophenol (2,4-DCP) by Ni/Fe nanoparticles in the presence of humic acid (HA) was investigated. We found that, as high performance liquid chromatography (HPLC) was used, the 2,4-DCP was first quickly reduced to o-chlorophenol (o-CP) andp-chlorophenol (p-CP), and then reduced to phenol as the final product. Our experimental results indicated that HA had an adverse effect on the dechlorination of 2,4-DCP by Ni/Fe nanoparticles, as the HA concentration increased, the removal rate decreased evidently. It also demonstrated that 2,4-DCP was reduced more easily to o-CP than to p-CP, and that the sequence of the tendency in dechlorination of intermediates was p-CP>o-CP. Transmission electron microscope (TEM) showed that HA could act as an adsorbate to compete reactive sites on the surface of Ni/Fe nanoparticles to decrease the dechlorination rate. Also we con-cluded that the dechlorination reaction of 2,4-DCP over Ni/Fe nanoparticles progressed through catalytic reductive dechlorination.     

Effect of a biological activated carbon filter on particle counts

Due to the importance of biological safety in drinking water quality and the disadvantages which exist in traditional methods of detecting typical microorganisms such as Cryptosporidium and Giardia, it is necessary to develop an alternative. Particle counts is a qualitative measurement of the amount of dissolved solids in water. The removal rate of particle counts was previously used as an indicator of the effectiveness of a biological activated carbon （BAC） filter in removing Cryptosporidium and Giardia. The particle counts in a BAC filter effluent over one operational period and the effects of BAC filter construction and operational parameters were investigated with a 10 m^3/h pilot plant. The results indicated that the maximum particle count in backwash remnant water was as high as 1296 count/ml and it needed about 1.5 h to reduce from the maximum to less than 50 count/ml. During the standard filtration period, particle counts stay constant at less than 50 count/ml for 5 d except when influenced by sand filter backwash remnant water. The removal rates of particle counts in the BAC filter are related to characteristics of the carbon. For example, a columned carbon and a sand bed removed 33.3% and 8.5% of particles, respectively, while the particle counts in effluent from a cracked BAC filter was higher than that of the influent. There is no significant difference among particle removal rates with different filtration rates. High post-ozone dosage （〉2 mg/L） plays an important role in particle count removal; when the dosage was 3 mg/L, the removal rates by carbon layers and sand beds decreased by 17.5% and increased by 9.5%, respectively, compared with a 2 mg/L dosage.     

Science Letters:Proteomic analysis of differentially expressed proteins in mice with concanavalin A-induced hepatitis

Objective:To find new protein biomarkers for the detection and evaluation of liver injury and to analyze the relationship between such proteins and disease progression in concanavalin A (Con A)-induced hepatitis.Methods:Twenty-five mice were randomly divided into five groups:an untreated group,a control group injected with phosphate buffered saline (PBS),and groups with Con A-induced hepatitis evaluated at 1,3 and 6 h.Two-dimensional gel electrophoresis (2-DE) and mass spectrometry (MS) were used to identif...     

Adsorption of ruthenium ions on activated charcoal： influence of temperature on the kinetics of the adsorption process

INTRODUCTION Time dependence study of metal ions adsorptionon solids provides valuable information on the ad-sorption process and its mechanism. Rate of metalions adsorption process is dependent on a number offactors such as agitation of the solution, the state ofmetal ions in solution, concentration of metal ions andtemperature (Benes and Majer, 1980). Temperature isthe parameter generally ignored in most adsorptionstudies (Bangash and Hanif, 1992; Afzal et al., 1993;Atun and Kil…     

Science Letters:A new quantitative model of ecological compensation based on ecosystem capital in Zhejiang Province, China

Ecological compensation is becoming one of key and multidiscipline issues in the field of resources and environ-mental management. Considering the change relation between gross domestic product (GDP) and ecological capital (EC) based on remote sensing estimation, we construct a new quantitative estimate model for ecological compensation, using county as study unit,and determine standard value so as to evaluate ecological compensation from 2001 to 2004 in Zhejiang Province, China. Spatial differences of the ecological compensation were significant among all the counties or districts. This model fills up the gap in the field of quantitative evaluation of regional ecological compensation and provides a feasible way to reconcile the conflicts among benefits in the economic, social, and ecological sectors.     

Science Letters:Detection of Catabacter hongkongensis in polluted European water samples

The Catabacteriaceae is a new bacterial family with a unique member: Catabacter hongkongensis is a strictly anaerobic, non-sporulating, Gram-positive coccobacillus that is phylogenetically related to some clostridial clusters. Little is known of its epidemiology and environmental distribution, but the inclusion of its 16S rRNA gene sequence in GenBank has allowed it to be detected qualitatively. As a first approach for prospective surveys, a real-time polymerase chain reaction (PCR) procedure to identify C. hongkongensis has been developed. The presence of Catabacteriaceae in 29 water bodies subjected to possible human or animal impact has been investigated. Four of them were positive. The results confirm that highly polluted water can contain C. hongkongensis.     

氨水浓度对果壳活性炭结构及性能的影响

采用氨水浸渍法对果壳活性炭进行改性处理,讨论不同氨水浓度（5%、10%、15%、20%）对果壳活性炭结构及性能的影响。采用场发射扫描电镜、比表面及孔径分析仪及紫外分光光度计对改性后的果壳活性炭结构及吸附性能进行研究。结果表明:氨水浓度对果壳活性炭的结构及吸附性能有显著影响,当氨水浓度为10%时,活性炭表面形态清晰,凹槽分布均匀,比表面积提高至775.1382m2/g,较改性前提高了6.5%;改性前后活性炭微孔孔径集中分布在3.5 nm;果壳活性炭的吸附率随氨水浓度的变化而变化,当氨水浓度为10%和15%时,吸附率分别达到86.51%和86.54%,吸附率相比改性前有所提高。而当氨水浓度进一步增加时,活性炭对苯酚的吸附率略微下降。     

急性肾功能衰竭家兔心肌损伤的体液机制

目的：观察急性肾功能衰竭（ARF）家兔心肌匀浆自由基、一氧化氮的变化，探讨心肌损伤的体液机制。方法：60只家兔均分为四组（n=15）。ARF模型1组：皮下注射1％HgCl2（1．3ml／kg．bw）；ARF模型2组：肌肉注射50％甘油（10ml／kg．bw）；以等量生理盐水代替HgCl2和甘油作为对照1、2组。24h后，所有动物颈总动脉放血备检，并选择固定位置。制备10％心肌匀浆。经Aeroset型全自动生化分析仪测定血清反映肾功能的生化指标。检测心肌匀浆丙二醛（MDA）、超氧化物歧化酶（SOD）、一氧化氮（NO）及其合酶（NOS）的变化。结果：与相应对照组比较，ARF模型1、2组心匀浆SOD活性下降、MDA含量升高（P〈0．05），ARF模型1、2组心匀浆NO含量增强、NOS及iNOS活性增强（P〈0．05～0．01）。结论：ARF家兔心肌损伤的机制与自由基损伤及NO升高有关。     

Review: Perspectives on the metallic interconnects for solid oxide fuel cells

The various stages and progress in the development of interconnect materials for solid oxide fuel cells (SOFCs) over the last two decades are reviewed. The criteria for the application of materials as interconnects are highlighted. Interconnects based on lanthanum chromite ceramics demonstrate many inherent drawbacks and therefore are only useful for SOFCs operating around 1000℃. The advance in the research of anode-supported flat SOFCs facilitates the replacement of ceramic interconnects with metallic ones due to their significantly lowered working temperature. Besides, interconnects made of metals or alloys offer many advantages as compared to their ceramic counterpart. The oxidation response and thermal expansion behaviors of various prospective metallic interconnects are examined and evaluated. The minimization of contact resistance to achieve desired and reliable stack performance during their projected lifetime still remains a highly challenging issue with metallic interconnects. Inexpensive coati     

脑梗塞患者血中一氧化氮对血小板功能的影响

[目的]研究脑梗塞患者血中一氧化氮(NO)的含量与血小板功能之间的关系.[方法]将20例脑梗塞患者分别于发病急性期和稳定期采用硝酸还原酶法测血中NO含量;用光电比浊法和免疫荧光分析法分别测定血小板聚集率(PAgT)和血小板α-颗粒膜蛋白(GMP-140)水平;同时检测正常对照15例[结果]血清中NO含量在发病急性期较正常对照明显增高(P<0.01).同时,PAgT与正常对照有显著性差异(PADP<0.05,PADR<0.01);而血小板GMP-140在急性期和稳定期较正常对照均有显著性差异(P<0.01).[结论]脑梗塞发病急性期随着血中NO含量的增高,导致PAgT受抑,血小板GMP-140水平减低.     

Science Letters:Filament geometrical model and nozzle trajectory analysis in the fused deposition modeling process

The geometrical model of the filament during the fused deposition modeling (FDM) process was firstly proposed based on three different models, tractrix, parabola, and catenary. Comparing with the actual measured filament curves on the Stratasys 1600 FDM machine, it is indicated that the tractrix model had the best agreement with the actual measured curves. With the analytical simulation, the nozzle trajectories in the straight-line deposition road, circle road, and arbitrary continuous curve road were deduced, according to the traxtric based geometrical model of the filament.     

碳排放权配额统一增价拍卖均衡下企业减排研究

由于碳排放权资源的稀缺性,过高的碳排放权拍卖价格将极大地增加企业的生产运营成本,从而迫使企业考虑投资以降低碳排放成本。针对低碳产品敏感的消费者建立产销模型,由竞拍企业的碳排放权需求函数在统一增价拍卖中形成拍卖均衡,以企业自身收益最大化为决策标准,给出最优减排决策。结论表明:碳排放总量的大小直接决定了拍卖均衡价格的高低,碳排放权拍卖总量的控制是经济结构调整的一个有效措施。     

Science Letters: Quantification of Helicobacter pylori levels in soil samples from public playgrounds in Spain

Helicobacter pylori are ubiquitous Gram-negative bacteria with a high estimated level of infection in the world populations, but a majority of the infected persons are asymptomatic. This pathogen has been classified by the World Health Organization as a class I carcinogen and recognized as the causal agent of most peptic ulcers and chronic gastritis that might lead to stomach cancer. Although not all the transmission pathways of these bacteria into humans have been properly identified, enough data have sugg...     

Inhibitory effect of Jeju endemic seaweeds on the production of pro-inflammatory mediators in mouse macrophage cell line RAW 264.7

Seaweed has been used in traditional cosmetics and as a herbal medicine in treatments for cough,boils,goiters,stomach ailments,and urinary diseases,and for reducing the incidence of tumors,ulcers,and headaches.Despite the fact that seaweeds are frequently used in the practice of human health,little is known about the role of seaweed in the context of inflammation.This study aimed to investigate the influence of Jeju endemic seaweed on a mouse macrophage cell line(RAW 264.7) under the stimulation of lipopolysaccharide(LPS).Ethyl acetate extracts obtained from 14 different kinds of Jeju seaweeds were screened for inhibitory effects on pro-inflammatory mediators.Our results revealed that extracts from five seaweeds,Laurencia okamurae,Grateloupia elliptica,Sargassum thun-bergii,Gloiopeltis furcata,and Hizikia fusiformis,were potent inhibitors of the production of pro-inflammatory mediators such as nitric oxide(NO),prostaglandin E2(PGE2),interleukin-6(IL-6),and tumor necrosis factor-α(TNF-α).Based on these results,the anti-inflammatory effects and low cell toxicity of these seaweed extracts suggest potential thera-peutic applications in the regulation of the inflammatory response.     

Study on the neurotoxic effects of low-level lead exposure in rats

Objective: To investigate effects of developmental lead exposure on nitric oxide synthase (NOS) activity in different brain regions and on N-methyl-D-aspartate (NMDA) receptor mRNA expression in the hippocampus of rats. On the basis of these observations, we explored possible mechanisms by which lead exposure leads to impaired learning and memorizing abilities in children. Methods: A series of rat animal models exposed to low levels of lead during the developing period was established (drinking water containing 0.025%, 0.05% and 0.075% lead acetate). NOS activities in the hippocampus, the cerebral cortex, the cerebellum and the brain stem were determined with fluorescence measurement and levels of mRNA expression of the NMDA receptor 2A (NR2A) subunit and NMDA receptor 2B (NR2B) subunit in the rat hippocampus were measured with Retro-translation (RT-PCR). Results: There were no differences in the body weight of rat pups between any of the groups at any given time (P>0.05). The blood lead level of Pb-exposed rat pups showed a systematic pattern of change: at 14 d of age, it was lower than that at 7 d of age, then rising to the peak level at 21 d and finally falling to lower levels at 28 d. The hippocampal NOS activities of lead-exposed groups were all lower than that of the control group on the 21st and 28th day (P<0.01). NOS activities in the cerebellum of lead-exposed groups were all lower than that of the control group on the 21st and 28th day (P<0.001) and the NOS activity of the 0.025% group was significantly lower than that of the 0.05% and 0.075% groups on the 28th day (P<0.05). NOS activity in the cerebral cortex of the 0.075% group was significantly lower than that of the control, 0.025% and 0.05% groups on the four day spans (P<0.001). There was no significant difference of NOS activity in the brain stem between any lead-exposed group and the control group on the four day spans. In the 0.05% and the 0.075% groups, the level of NR2A mRNA expression was higher than that in the control group at 7 d and 14 d of age (P<0.05). In the 0.025% group, the level of NR2A was found to be higher than that in the control group at 7 d of age only (P<0.05). No significant differences were found for the levels of NR2B mRNA expression between any of the groups at any given time. Conclusions: NOS activity in the hippocampus, the cerebral cortex and the cerebellum are inhibited by lead exposure. The degree of the inhibitory effect depends on the time span of exposure and the lead concentration. Developmental low-level lead exposure was found to raise the level of NR2A mRNA expression in the hippocampus of rats. Developmental low-level lead exposure does not affect the level of NR2B mRNA expression in the hippocampus.