Experimental study about the agglomeration behavior in slurry prepared by adding excess polyelectrolyte dispersant

In our previous paper we found that the particles in the slurry can agglomerate by adding larger amount of polyelectrolyte dispersant compared to that needed to attain well dispersion. Thus, the dependency of initial particle concentration on the agglomeration and its mechanism in slurry prepared by adding excess polyelectrolytes was experimentally discussed. It was shown that agglomeration behavior strongly depends on the additive amount of polyelectrolytes, not on the polyelectrolyte concentration in the solution. It was also found that the dominant factor of agglomeration in slurry prepared by adding extra polyelectrolytes should be the compression of the electrical double layer by the increased counter ion concentration, not by the so called depletion effect or by pH change. Interestingly, the final sediment had a relatively high packing fraction and good flowability in the case of the agglomerated slurry with extra polyelectrolytes compared to that of the agglomerated slurry with an additional NaCl solution.     

Highlights of the Salt Extraction Process

This article presents the salient features of a new process for the recovery of metal values from secondary sources and waste materials such as slag and flue dusts. It is also feasible in extracting metals such as nickel and cobalt from ores that normally are difficult to enrich and process metallurgically. The salt extraction process is based on extraction of the metals from the raw materials by a molten salt bath consisting of NaCl, LiCl, and KCl corresponding to the eutectic composition with AlCl₃ as the chlorinating agent. The process is operated in the temperature range 973 K (700°C) to 1173 K (900°C). The process was shown to be successful in extracting Cr and Fe from electric arc furnace (EAF) slag. Electrolytic copper could be produced from copper concentrate based on chalcopyrite in a single step. Conducting the process in oxygen-free atmosphere, sulfur could be captured in the elemental form. The method proved to be successful in extracting lead from spent cathode ray tubes. In order to prevent the loss of AlCl₃ in the vapor form and also chlorine gas emission at the cathode during the electrolysis, liquid aluminum was used. The process was shown to be successful in extracting Nd and Dy from magnetic scrap. The method is a highly promising process route for the recovery of strategic metals. It also has the added advantage of being environmentally friendly.     

Efficient arsenic(V) removal from water by ligand exchange fibrous adsorbent

This study is an efficient arsenic(V) removal from contaminated waters used as drinking water in adsorption process by zirconium(IV) loaded ligand exchange fibrous adsorbent. The bifunctional fibers contained both phosphonate and sulfonate groups. The bifunctional fiber was synthesised by graft polymerization of chloromethylstyrene onto polyethylene coated polypropylene fiber by means of electron irradiation graft polymerization technique and then desired phosphonate and sulfonate groups were introduced by Arbusov reaction followed by phosphorylation and sulfonation. Arsenic(V) adsorption was clarified in column methods with continuous flow operation in order to assess the arsenic(V) removal capacity in various conditions. The adsorption efficiency was evaluated in several parameters such as competing ions (chloride and sulfate), feed solution acidity, feed flow rate, feed concentration and kinetic performances at high feed flow rate of trace concentration arsenic(V). Arsenic(V) adsorption was not greatly changed when feed solutions pH at 3.0-7.0 and high breakthrough capacity was observed in strong acidic area below pH 2.2. Increasing the flow rate brings a decrease both breakthrough capacity and total adsorption. Trace level of arsenic(V) (0.015 mM) in presence of competing ions was also removed at high flow rate (750 h⁻¹) with high removal efficiency. Therefore, the adsorbent is highly selective to arsenic(V) even in the presence of high concentration competing ions. The adsorbent is reversible and reusable in many cycles without any deterioration in its original performances. Therefore, Zr(IV) loaded ligand exchange adsorbent is to be an effective means to treat arsenic(V) contaminated water efficiently and able to safeguard the human health.     

International Comparison of Fire Department Injuries

Firefighting remains a dangerous profession. The objective of this study was to compare injury rates among career and volunteer fire departments internationally. Methods: Injury and staffing data were collected for 2004–2009. All reported, lost-time, and activity-specific injury rates were calculated for fireground, medical, training and physical exercise activities. Injury rates were also adjusted for number of fireground and medical responses, and average annual training hours. Injury rates were generally higher in the U.S. than in Commonwealth nation and Japanese fire departments. Lost-time injury rates varied markedly among fire departments, from 0.6 (95% CI 0.4–0.9) to 23.5 (95% CI 22.4–22.7) injuries per 100 firefighters per year. The greatest pair-wise differences in lost-time injury rates were seen in the fireground and medical call activities, and these differences persisted when the rates were adjusted by the number of firefighters responding to fireground and medical incidents, respectively. Injury rates vary substantially across fire departments, suggesting that substantial improvements could result from adoption of more optimal health and safety approaches.     

Establishment of a model substrate oil for antioxidant activity assessment by oil stability index method

A model substrate oil using methyl linoleate was established for the determination of the antioxidant activity by Oil Stability Index (OSI) method. OSI values for methyl linoleate with different concentrations (5–100%) in silicone oil were measured at different temperatures (70–120°C). As the temperature increased, the OSI value decreased in each concentration of methyl linoleate. Optimal temperature and concentration of antioxidants, α-tocopherol, and butylated hydroxytoluene on OSI values for 10% methyl linoleate model oil was measured at 90, 100, 110, and 120°C. The logarithmic relationship between temperature and OSI using model substrate oil was similar to that of soybean oil. Furthermore, application of some spice extracts to this model oil system was carried out to give results thhat compared well with those available in the literature. Thus, the procedure using methyl linoleate-silicone oil as a model substrate oil is available for evaluating the antioxidant activity by the OSI method.     

Detailed Structure and Pathophysiological Roles of the IgA-Albumin Complex in Multiple Myeloma

Immunoglobulin A (IgA)-albumin complexes may be associated with pathophysiology of multiple myeloma, although the etiology is not clear. Detailed structural analyses of these protein–protein complexes may contribute to our understanding of the pathophysiology of this disease. We analyzed the structure of the IgA-albumin complex using various electrophoresis, mass spectrometry, and in silico techniques. The data based on the electrophoresis and mass spectrometry showed that IgA in the sera of patients was dimeric, linked via the J chain. Only dimeric IgA can bind to albumin molecules leading to IgA-albumin complexes, although both monomeric and dimeric forms of IgA were present in the sera. Molecular interaction analyses in silico implied that dimeric IgA and albumin interacted not only via disulfide bond formation, but also via noncovalent bonds. Disulfide bonds were predicted between Cys34 of albumin and Cys311 of IgA, resulting in an oxidized form of albumin. Furthermore, complex formation prolongs the half-life of IgA molecules in the IgA-albumin complex, leading to excessive glycation of IgA molecules and affects the accumulation of IgA in serum. These findings may demonstrate why complications such as hyperviscosity syndrome occur more often in patients with IgA dimer producing multiple myeloma.     

Radical formation site of cerebral complex I and Parkinson's disease

Paraquat was reduced to the paraquat radical via complex I in bovine cerebral mitochondria and accelerated lipid peroxidation. Thirty-kilodalton subunit of complex I was considered to be the radical formation site, because of its marked destruction by the paraquat radical. The lipid peroxidation by the paraquat radical was suppressed not only by superoxide dismutase (SOD) but also by mannitol. The destruction of complex I subunits via lipid peroxidation must have been caused by the hydroxyl radical which was formed from the superoxide radical. The same phenomenon was observed by using 1-methylnicotinamide (MNA), which contains the same partial structure as paraquat in itself and is metabolized from nicotinamide in a living body. We observed NADH oxidation by MNA via cerebral complex I (Km = 26.3 mM), and MNA destroyed some complex I subunits, especially 30-kilodalton protein. Paraquat might be useful for studying the pathogenesis of Parkinson's disease (PD) in vitro, and MNA is expected to be one of the causal substances of PD from the viewpoint of the oxidative stress theory.     

Simultaneous determination of N-methylcarbamates and their metabolites in citrus fruits by HPLC avoiding use of halogenic solvents

Twenty-one N-methylcarbamates (NMCs) and 12 of their metabolites or isomers in citrus fruits were simultaneously determined avoiding use of dichloromethane. NMCs in lemon, orange, and grapefruit were extracted with acetone, then the acetone was evaporated off and sodium chloride was added before extraction with ethyl acetate. The extract was evaporated and the residue was cleaned up on a combined mini-column set of Supelclean ENVI-Carb and Mega Bond Elut SAX cartridges. NMCs were determined by HPLC with post-column reaction and fluorescence detection. All of the NMCs in the orange sample were determined without interfering peaks. However 8 NMCs in lemon extract and 10 NMCs in grapefruit extract were not detected because interfering peaks appeared at similar retention times to those of the NMCs. These NMCs were determined using LC/MS (SIM) and were well recovered. Eighty-three data sets obtained by HPLC and LC/MS showed good similarity, with r2 = 0.9178. Recoveries were 60.1 to 97.8% for major NMCs at a fortification level of 0.1 ppm. The limit of detection by HPLC was 0.005 ppm NMCs in samples and a similar level applied to LC/MS.     

On-chip enzyme immunoassay of a cardiac marker using a microfluidic device combined with a portable surface plasmon resonance system

This paper reports a miniaturized immunosensor designed to determine a trace level cardiac marker, B-type natriuretic peptide (BNP), using a microfluidic device combined with a portable surface plasmon resonance (SPR) sensor system. Sample BNP solution was introduced into the microchannel after an immunoreaction with acetylcholine esterase-labeled antibody (conjugate), and only unbound conjugate was trapped on the BNP-immobilized surface in the flow channel. Then, the thiol compound generated by the enzymatic reaction with the trapped conjugate was accumulated on a gold thin film located downstream in the microchannel to monitor the real-time SPR angle shift. We achieved a detectable concentration range of 5 pg/mL-100 ng/mL by monitoring the SPR angle shift, which covers the required detection range for the BNP concentrations found in blood. This success resulted from the use of a T-shaped microfluidic device structure, which prevents the sample solution from flowing over the gold film used for SPR detection. We were able to measure trace levels of BNP peptide (15 fg) within 30 min since the procedure with our immunosensor is simpler than a multistep immunoassay through the simultaneous use of a labeled enzymatic reaction and the real-time monitoring of enzymatic product accumulation in the microfluidic device. We employed the procedure to detect serum BNP by using spiked samples in human serum and achieved satisfactory recovery for heat-treated samples to denature the esterase in the serum before the immunoreaction.