Isolation and Spectroscopic Characterization of Eu@C72

A new Eu-endohedral fullerene cage, namely, Eu@C₇₂, was synthesized, separated, and a single isomer, Eu@C₇₂-I, has been isolated by multi-step HPLC for the first time and characterized by LDI-TOF mass spectrometry, UV-Vis and EPR spectroscopy. Additionally, a second isomer, Eu@C₇₂-II, has been separated by HPLC and identified by LDI-TOF mass spectrometry.     

Complementarity determining region residues aspartic acid at H55, serine at H95 and tyrosines at H97 and L96 play important roles in the B72.3 antibody-TAG72 antigen interaction

Structural analysis derived from the crystallographic studyof the chimeric B72.3 antibody illustrated some major atomicinteractions between complementarity determining region (CDR)residues. For example, hydrogen bonds are formed between H35/H95,L50/H97, H53/H55 and H96/L96 respectively. These CDR residuesmay play important roles in the B72.3–TAG72 (antibody-antigen)interaction either by direct interaction with the TAG72 antigenor by maintaining a CDR loop conformation through atomic interactionsbetween CDR residues. In order to confirm these assumptions,we altered these CDR residues by site-directed mutagenesis anddetermined binding affinities of these mutant chimeric antibodiesfor the TAG72 antigen in a solid-phase radioimmunoassay. Wefound that H55, H95, H97 and L96 are important CDR residuesfor the B72.3–TAG72 interaction. Single amino acid substitutionsof aspartic acid and serine by alanine at H55 of CDR2 and atH95 of CDR3 respectively and of tyrosine by phenylalanine atH97 and L96 of CDR3, significantly reduced the binding affinityfor the TAG72 antigen by 20-, 8-, 16- and 45-fold respectively.Therefore, this study reveals some of the requirements for maintainingthe integrity of the B72.3 antibody combining sites.     

Parameterized complexity of control problems in Maximin election

Elections are a central model in a variety of areas. This paper studies parameterized computational complexity of five control problems in the Maximin election. We obtain the following results: constructive control by adding candidates is W[2]-hard with respect to the parameter “number of added candidates”; both constructive and destructive control by adding/deleting voters are W[1]-hard with respect to the parameter “number of added/deleted voters”.     

Detecting change-points in Markov chains

Markov chains provide a flexible model for dependent random variables with applications in such disciplines as physics, environmental science and economics. In the applied study of Markov chains, it may be of interest to assess whether the transition probability matrix changes during an observed realization of the process. If such changes occur, it would be of interest to estimate the transitions where the changes take place and the probability transition matrix before and after each change. For the case when the number of changes is known, standard likelihood theory is developed to address this problem. The bootstrap is used to aid in the computation of p-values. When the number of changes is unknown, the AIC and BIC measures are used for model selection. The proposed methods are studied empirically and are applied to example sets of data.     

Improved electrocatalytic kinetics of nickel hydroxide nanoparticles on Vulcan XC-72R carbon black towards alkaline urea oxidation reaction

Nickel hydroxide nanoparticles were fabricated on Vulcan XC-72R carbon black using various reducing agents through assisted microwave polyol process. The formed electrocatalysts using sodium borohydride [Ni(OH)₂/C–NB], ethylene glycol [Ni(OH)₂/C–EG] and a mixture of them [Ni(OH)₂/C–EGNB] displayed an electrocatalytic activity towards urea oxidation in NaOH solution. The oxidation peak potential and current density values were greatly influenced by the employed reducing agent. Lower onset and peak potential values were measured at Ni(OH)₂/C–EGNB, while Ni(OH)₂/C–EG exhibited the highest oxidation current density during urea oxidation reaction. Electroactive surface area measurements revealed that the number of available active sites for the oxidation reaction was arranged in an ascending order as Ni(OH)₂/C–NB < Ni(OH)₂/C–EGNB < Ni(OH)₂/C–EG. The diffusion coefficient of urea molecules at Ni(OH)₂/C–EG and Ni(OH)₂/C–EGNB was 14.69 and 5.90 times higher than that at Ni(OH)₂/C–NB. Stable performance was measured at all studied electrocatalysts over prolonged operation suggesting their valuable application as efficient anode materials in direct urea oxidation fuel cells.     

Sage of Lacock

Abstract

‘The good is oft interred with their bones.’ Much of what has been written of William Henry Fox Talbot has done him meagre justice: criticism for patenting his inventions, accusations that he patented the ideas of others, denigration of the importance of his discoveries. Though acknowledged as a scientist, his place as an artistic worker in the medium he invented has not been appreciated.     

辣根过氧化物酶在三种孔材料上的在线固定化研究

利用已建立的顺序注射紫外可见分析系统,以硅基介孔材料MCM-41、SBA-15和炭材料XC-72作为载体,研究和比较了辣根过氧化物酶(HRP)在3种无机孔材料上的在线吸附行为。结果表明,HRP在XC-72上的负载量和结合稳定性高于MCM-41和SBA-15,且以XC-72为载体制备的固定化HRP具有较高的活性和良好的操作稳定性。     

D-72磺酸树脂催化柠檬醛环化合成对伞花烃

以D-72磺酸树脂为催化剂,催化柠檬醛环化反应合成对伞花烃,考察了反应介质、柠檬醛的体积分数、催化剂用量、反应温度和反应时间对柠檬醛转化率和对伞花烃产率的影响。实验结果表明,以乙酸乙酯为介质,在柠檬醛体积分数为7.5%,催化剂用量为0.4 g,70℃下反应80 min,柠檬醛的转化率为100%,对伞花烃的产率为73.65%。     

废弃高密度钻井液固液分离的实验研究

对废弃高密度钻井液进行了稀释沉降和化学絮凝脱水的固液分离实验研究。结果表明，该方法不仅回收了９０％的加重材料（重晶石粉），而且破坏了废钻井液的胶体体系，使其絮凝脱水，实现固液分离，脱水残渣可安全地埋入地下，有效地解决了废钻井液对环境的污染问题。     

高速大深度新型FIFO存储器IDT72V3680的应用

在介绍了FIFO芯片基本结构和功能的基础上 ,介绍了一个有极大深度的高速先入先出(FIFO)存储器芯片IDT72V3680的功能特点和应用要点 ,给出了其在基于PCI总线的高速数据传输系统的运用实例以及与PCI总线的接口电路