Adsorption of four perfluorinated acids on non ion exchange polymer sorbents

Perfluorinated compounds (PFCs) have attracted global concern due to their ubiquitous distribution and properties of persistence, bio accumulation and toxicity. The process of adsorption has been identified as an effective technique to remove PFCs in water. Different non ion-exchange polymeric adsorbents were tested with regard to their sorption kinetics and isotherms at low PFCs concentrations. Selected PFCs were perfluorobutanoic acid (PFBA), perfluoroheptanoic acid (PFHpA), perfluorooctanoic acid (PFOA) and perfluorodecanoic acid (PFDA) and the tested polymers were three types of Dowex optopores (V-493, V503, and L493), Amberlite XAD-4, and Filtrasorb 400 (Granular Activated Carbon-GAC). We observed the selective adsorption of PFCs on synthetic polymers. For PFDA, Amberlite XAD-4 gave the Freundlich adsorption constant of 2,965 (microg PFCs/g sorbent)(microg PFCs/L)(-n), which was higher than that of GAC (121.89 (microg PFCs/g sorbent) (microg PFCS/L)(-n)). In the case of PFBA, GAC showed better performance (13.36) (microg PFCs/g sorbent) microg PFCS/L)(-n) than synthetic polymers (0.62-5.23) (microg PFCs/g sorbent) (microg PFCS/L)(-n). Adsorption kinetics of all adsorbents were well described (R2 = 0.85-1) by pseudo-second order kinetic model. Sorption capacity was influenced by initial PFCs concentration for all adsorbents. GAC reached the equilibrium concentration within 4 hours, Amberlite XAD 4 reached it within 10 hours and other polymers took more than 70 hours.     

Effect of annealing on d.c. conductivity of V2O5-SnO-TeO2 glasses

The d.c. conductivity (σ) of V₂O₅-SnO-TeO₂ glasses prepared by the press-quenching method was studied at temperatures from room temperature (RT) to 473 K, and the effect of annealing on σ was investigated. The conductivity of 50V₂O₅·20SnO·30TeO₂ glass was determined to be 3.98×10⁻⁴ Scm⁻¹ at 473 K and was unchanged for annealing (6–48 h) at 493 K, lower than T_g = 501 K, while its density increased with annealing time. These glasses were found to be n-type semiconductors, and the conduction was confirmed to be due to adiabatic small polaron hopping for V₂O₅ ≧ 50 mol%, and non-adiabatic for V₂O₅ < 50 mol%. The activation energy for conduction, W, decreased with annealing time. Variations in oxygen molar volume of the glasses with annealing time inferred a change in glass structure, from loosely to closely packed, resulting in a decrease in vanadium ion spacing with annealing. This caused an increase in the polaron band width, producing a decrease in polaron hopping energy and W. The effect of annealing time on the density of 50V₂O₅·20SnO·30TeO₂ glass was explained adequately by Winter's formula.     

Multiple evaluations of the removal of pollutants in road runoff by soil infiltration

Groundwater replenishment by infiltration of road runoff is expected to be a promising option for ensuring a sustainable urban water cycle. In this study, we performed a soil infiltration column test using artificial road runoff equivalent to approximately 11-12 years of rainfall to evaluate the removal of pollutants by using various chemical analyses and bioassay tests. These results indicated that soil infiltration treatment works effectively to remove most of the pollutants such as organic matter (chemical oxygen demand (CODMn) and dissolved organic carbon (DOC)), P species, polycyclic aromatic hydrocarbons (PAHs), numerous heavy metals and oestrogenic activities. Bioassay tests, including algal growth inhibition test, Microtox and mutagen formation potential (MFP) test, also revealed effective removal of toxicities by the soils. However, limited amounts of NO3, Mn, Ni, alkaline earth metals, perfluorooctane sulphonate (PFOS) and perfluorooctane sulphonamide (FOSA) were removed by the soils and they possibly reach the groundwater and cause contamination.     

Microbial degradation of cyanobacterial cyclic peptides

Bacterial strain B-9 possesses hydrolytic enzymes capable of degrading microcystins (MCs) and nodularin that are toxic cyclic peptides produced by cyanobacteria. In the present study, the degradation activities of the cell extract of B-9 against non-toxic cyanobacterial cyclic peptides other than the MCs and nodularin were investigated, and the degradation products were analyzed by liquid chromatography/ion trap tandem mass spectrometry (LC/ITMS). It was confirmed that B-9 could also degrade these cyanobacterial cyclic peptides by hydrolysis of their peptide bonds. These results indicated that this bacterium possesses a very unique hydrolytic activity that can degrade structurally different cyclic peptides and that this may be effective for the detoxification of hazardous cyclic peptides.     

Detection of surface antigens on living cells through incorporation of immunorecognition into the distinct positioning of cells with positive and negative dielectrophoresis

Rapid determination of surface antigens on cells is possible by immobilization of cells accumulated by positive dielectrophoresis (p-DEP) via effective surface immunoreactions and removal of unbound cells by negative DEP (n-DEP). The DEP device for cell manipulation comprises a microfluidic channel with an upper indium tin oxide (ITO) electrode and a lower ITO microband array electrode (band electrode) modified with an antibody. Cells with the surface antigen introduced into the channel immediately accumulated on the surface of the band electrode during p-DEP generated by the application of ac voltage between the ITO electrode and the band electrode to immobilize by the specific antibody. The removal of accumulated cells to the gap region during n-DEP was used for rapid estimation of the residual cells with a specific surface antigen. We demonstrate here that human promyelocytic leukemia cells with the surface antigen CD33 can be captured on a band electrode modified with anti-CD33 antibody. The time required for the determination of the surface antigen using this compelled accumulation of cells by p-DEP and the separation of unbound cells by n-DEP is decreased to 60 s compared to that required by a cell binding assay using microtiter plates (30 min). Furthermore, the present method for a novel cell binding assay does not require pretreatment such as target labeling or washing of unbound cells and thereby enhancing throughput in the clinic and in cytobiology studies.     

Initial stages of high-temperature CaF2/Si(001) epitaxial growth studied by surface X-ray diffraction

Surface X-ray diffraction was applied to study structure of the fluorite-silicon interface forming upon epitaxial growth of CaF2 on Si(001) surface kept at 750 degrees C. Samples with CaF2 coverage of 1.5-4 (110)-monolayers were grown and in-situ characterized using synchrotron radiation. The 3 x 1-like surface reconstruction was observed in agreement with the previous studies by electron diffraction. Interestingly, a well pronounced splitting of the fractional x 1/3 reflections was revealed. This splitting was ascribed to the effect of antiphase domain boundaries in the row-like structure of the interface layer. The in-plane integrated intensities were used to reconstruct two-dimensional atomic structure of the high-temperature CaF2/Si(001) interface.     

Surgical strategy for abdominal aortic aneurysm with concurrent symptomatic malignancy

In an attempt to improve the guidelines for concurrent management of concomitant abdominal aortic aneurysm (AAA) and symptomatic malignancy, a retrospective study was undertaken. A total of 186 AAA repairs were performed electively, and 25 patients (13.4%) had concurrent symptomatic malignancy from April 1986 to March 1997. Fourteen patients underwent a one-stage operation, including five abdominoperineal rectal resections, four subtotal gastrectomies, three total gastrectomies, and two right hemicolectomies. Eleven others underwent a two-stage operation, including four with total gastrectomy and left hemicolectomy followed by AAA repair, as well as two with right hemicolectomy and one with left hemicolectomy prior to AAA repair. There were no operative deaths or severe postoperative complications. Of the 25 patients, 22 (88.0%) are still alive during follow-up ranging from 8 months to 11 years. Our surgical approach to both lesions is as follows: (1) Using the transperitoneal approach alone, subtotal gastrectomy and abdominoperineal rectal resection can be safely done simultaneously. (2) Although total gastrectomy can also be performed concurrently, the approach used for each lesion is separate. (3) Colorectal resection is generally done separately. However, a one-stage operation can be performed using the thromboexclusion procedure for AAA repair in patients with right-sided colonic cancer or a temporary transverse colostomy for left-sided colorectal cancer.     

High-speed demonstration of an output interface driver forsingle-flux quantum systems

The high-speed operation of a one-channel output interface for a single-flux quantum (SFQ) system has been demonstrated. The interface consisted of a Josephson latching driver, a room-temperature semiconductor amplifier, and a decision circuit module. The Josephson latching driver was fabricated by using a 2.5-kA/cm² standard Nb junction process and used to amplify an SFQ pulse into a 5.5-mV level signal at 10 Gb/s. The interface converted the SFQ pulse signal into a nonreturn-to-zero signal having an amplitude of 1 V at 10 Gb/s