Immobilization of mushroom polyphenol oxidase on poly(allyl glycidyl ether-co-ethylene glycol dimethacrylate) macroporous beaded copolymers

Functional, macroporous, beaded copolymers containing epoxy groups were synthesized for immobilization of polyphenol oxidase (PPO) from edible mushroom (Agaricus bisporus). The effect of incorporation of two different sets of monomers such as glycidyl methacrylate (GMA) and allyl glycidyl ether (AGE) and the effect of cross-linking agent ethylene glycol dimethacrylate (EGDM) with varying cross-link densities on binding and expression of mushroom PPO activity were studied. The effect of porogen viz. cyclohexanol and hexanol on PPO immobilization was studied. AGE copolymers with hexanol as a porogen were found to give higher binding and expression of PPO activity than GE polymers. Cross-linking of amino groups of enzyme with 5% glutaraldehyde for 6 h gave a stable binding of PPO on AGE-75(Hex) polymer with storage half-life of approximately 25 days. Under optimum conditions, AGE-75(Hex) polymer gave 70.3% of activity yield while percent retention of PPO activity was found to be 83.5%. Immobilized PPO showed a broader pH, higher temperature and excellent storage stability.     

Quaternary nitrogen activated carbons for removal of perchlorate with electrochemical regeneration

Positively charged nitrogen functional groups were introduced onto the surface of granular activated carbon (GAC), and these increased perchlorate anion removal from drinking water sources. Nitrogen functionalization involved three treatment steps: (1) introducing oxygen groups onto the GAC, (2) incorporating nitrogen groups by thermal treatment in ammonia flow to replace O with N, and (3) quaternerizing pyridine-like groups to create positively charged pyridinium-like groups. Functionalized bituminous GAC provided 6 times more perchlorate removal than its predecessor, pristine bituminous GAC. The conversion of pyridine-like groups (after step 2) to pyridinium-like groups by quaternization (step 3) was confirmed by analysis of the XPS N 1s signals and surface charge analysis. Redox peaks, observed during cyclic voltammetry analysis of the functionalized GAC, evidenced that these nitrogen functional groups were electrochemically active, so that they sorbed perchlorate when they were oxidized, and then desorbed perchlorate when reduced. Moreover, after sorbing perchlorate onto pyridinium-GAC in RSSCTs, the GAC media could be regenerated by electrochemical reduction, and its capacity for perchlorate adsorption was mostly restored. This tailored functionality and redox regeneration of a relatively inexpensive media such as activated carbon could offer novel opportunity to the adsorption industry.     

抗FGF-2纳米抗体抑制碱烧伤诱导大鼠角膜血管新生

目的：研究抗成纤维细胞生长因子（FGF-2）纳米抗体对碱烧伤诱导的大鼠角膜血管生成的治疗作用。方法：将SD大鼠分为：假手术组（Sham），模型组（Model，直径为3 mm的浸有1 mol/L NaOH溶液圆形滤纸贴于大鼠眼角膜中央处30 s，制备大鼠碱烧伤血管生成模型）和治疗组（Treatment，术后7天至21天用3 mg/mL的抗FGF-2纳米抗体溶液滴眼，每日3次，每次10 μL，共14天）。通过体视显微镜和CD31免疫组织化学染色计算大鼠角膜血管生成情况。实时荧光定量PCR、酶联免疫吸附测定和免疫组织化学染色3种方法检测抗血管内皮生长因子（VEGF）和FGF-2的mRNA和蛋白表达水平。结果：（1）血管：治疗组较模型组的面积显著减少，血管管腔较窄（P<0.05），在药物干预14天后，差异最为显著；（2）FGF-2的mRNA和蛋白表达水平：模型组与治疗组的结果相近（P>0.05）；（3）VEGF的mRNA和蛋白表达水平：治疗组显著高于模型组（P<0.05）。此外，假手术组的持续给药也使得VEGF表达显著增加（P<0.05）。 结论：抗FGF-2纳米抗体可抑制由碱烧伤诱导的角膜血管新生，但也使得正常大鼠角膜或病理大鼠角膜的VEGF表达水平代偿性升高。     

Low temperature cleanup combined with magnetic nanoparticle extraction to determine pyrethroids residue in vegetables oils

To quantify trace pesticide residue in vegetable oil rapidly, low temperature cleanup combined with magnetic nanoparticle based solid phase extraction was developed to determine eight pyrethroids in vegetable oils, including tetramethrin, fenpropathrin, cypermethrin, decamethrin, fenvalerate, acrinathrin, permethrin and bifenthrin. Polystyrene coated magnetic nanoparticles were synthesised by a modified chemical coprecipitation combined with emulsion polymerisation method. The nanoparticles were afterwards characterised by Fourier transform-infrared spectroscopy, X-ray diffraction, transmission electron microscopy as well as vibrating sample magnetometer, and successfully employed as adsorbents for the magnetic solid phase extraction of pyrethroids which were cleaned up using low temperature approach in advance. Critical impact factors on the efficiency of the extraction method such as the mass of adsorbents used, volume and type of eluent solvent, extraction time as well as elution time were optimised subsequently. Regression analysis of the calibration curves of the eight pyrethroids yielded satisfactory correlation coefficients within the range of 0.980–0.998. Limit of detection and limit of quantification were calculated to be between 0.0290-0.0658 and 0.0890–0.1994 ng g⁻¹, respectively. Intra-day and inter-day reproducibility at different concentration levels also produced satisfactory recovery rates of 83.18–112.79% with relative standard deviations not exceeding 10.84% and 12.01%, respectively, suggesting desirable stability of the proposed method.     

Relevance and challenges in monitoring marine biotoxins in non-bivalve vectors

Seafood poisoning outbreaks can be caused by marine biotoxins which are naturally produced by harmful algal blooms. To minimize the risk of acute intoxications due to consumption of contaminated seafood a proper monitoring program must be in place. In recent decades several directives have been laid down by the European Commission to regulate known toxins, reassess their regulatory limits and update their reference detection methods. However, a revision of the seafood organisms that can act as toxin vectors has not been carried out. The control system has been designed based on physiological specificities of live bivalve mollusks. Although the prescribed controls in EC regulation 854/2004 apply to echinoderms, tunicates and marine gastropods, several difficulties are posed to a cost-effective monitoring program for these quite diverse and non-analogous groups of seafood organisms. Echinoderms, tunicates and marine gastropods are frequently secondary target species for toxins surveillance. In this study, the potential of non-bivalve organisms as toxin vectors and their threat for public health is evaluated based on their feeding behavior (i.e. filter-feeders, herbivores, predators), growth and metabolic rates, motile capacity and dynamics of toxin accumulation/elimination. A summary of previous reports on toxin accumulation and human incidents is presented to highlight the seafood species of higher risk to consumers, including crustaceans that are not listed in the EU directives for toxins monitoring and should be strongly considered as potent vectors of biotoxins to humans. Finally, the challenges in terms of sampling efforts and analytical determination for the regular surveillance of biotoxins in non-bivalve vectors are discussed.     

A comparative study of the effect of Pd-doping on the structural,optical, and photocatalytic properties of sol–gel derived anatase TiO2 nanoparticles

Pd-doped anatase TiO₂ nanoparticles were synthesized by a modified sol–gel deposition technique. The synthetic strategy is applicable to other transition and post-transition metals to obtain phase-pure anatase titania nanoparticles. This is important in the sense that anatase titania forms the most hydroxyl radicals (compared to other polymorphs like rutile, brookite, etc.) for better photocatalytic performance. XRD and Raman data confirm the phase-pure anatase formation. Doping of Pd²⁺ into Ti⁴⁺ sites (for substitutional doping) or interstitial sites (for interstitial doping) creates strain within the nanoparticles and is reflected in the XRD peak broadening and Raman peak shifts. This is because of the ionic radii difference between Ti⁴⁺(∼68 pm) and Pd²⁺(∼86 pm). XPS data confirm the formation of high surface titanol groups at the nanoparticle surface and a large number of loosely bound Ti³⁺–O bonds, both of which considerably enhance the photocatalytic activity of the doped nanoparticles. A comparative study with other metal doping (Ga) shows that TiO₂: Pd nanoparticles have more Ti³⁺–O bonds, which enhance the charge transfer rate and hence improve the photocatalytic activity compared to other transition and post-transition metal-doped titania nanostructures.     

酸洗废液制备聚合氯化铁形态及稳定性研究

以钢铁盐酸酸洗废液为原料,催化氧化制备聚合氯化铁(PFC)。考察了聚合氯化铁稳定性的影响因素,并采用Ferron逐时络合比色法考察了制备温度、HCl/Fe的质量比、P/Fe的摩尔比、熟化时间对聚合氯化铁中铁形态分布及转化规律的影响。研究结果表明:在制备温度为60℃、HCl/Fe≥0.45,P/Fe≥0.12时,催化氧化制备的聚合氯化铁能稳定存在6个月以上,不发生水解。催化氧化制备的PFC中铁主要以Fe(a)和Fe(c)的形式存在,Fe(b)含量很少,随着熟化时间的延长,Fe(b)在14天左右完全消失。随HCl/Fe的质量比及P/Fe的摩尔比的增大,Fe(a)、Fe(b)含量先增加后降低,Fe(c)含量先减少后增加。     

A nomograph for estimating annual cooling and heating energy requirements in buildings dominated by internal loads

This paper describes a nomograph that can be used as a design tool for estimating annual cooling and heating coil loads in interior zones of office buildings. Based on simplified relationships between the heat load on an air-conditioning system, internal heat generation and outdoor air intake rate, the equations for normalized anuual cooling and heating coil loads in interior zones of office buildings are derived as a function of outdoor air enthalpy, two variables related to the intensity of internal cooling load, and the minimum and maximum outdoor air intake rates. Normalization of heat load on an ari-conditioning system made it possible to construct a design nomograph which can be used to calculate the energy-saving effects of an economizer cycle (passive cooling with ventilation air) and an exhaust air heat recovery unit on annual cooling and heating coil loads at the schematic design stage.Example calculations using the nomographs for three locations in Japan show that the energy-sacing effects of economizer cycle and exhaust air heat recovery units are heavily dependent on the profiles of regional weather conditions. A validation study showed that annual cooling and heating coil loads estimated from the nomographs were in good agreement with those from a detailed computer-based calculation.     

On the preparation of a monoclinic (nearly) single crystal of zeolite HZSM-5

HZSM-5 appears to be ferroelastic. Application of a uniaxial mechanical stress during the orthorhombic/monoclinic transition of zeoltie HZSM-5 changes the population of the monoclinic twin domains. The volume fraction of one of the twin mates is changed from 0.5 (before application of mechanical stress) to 0.06 in the crystal studied.