Adsorption of urea,creatinine, and uric acid from three solution types using spherical activated carbon and its recyclability

In this paper, we propose that the urinary toxins from the wastewater be adsorbed on an adsorbent such as spherical activated carbon and the latter be regenerated by subjecting it to high temperatures to recycle activated carbon and also to recycle the water used in dialysis. We studied the adsorption of artificial waste dialysate, which is a mixed solution of urea, creatinine, and uric acid, and the separate solutions for each of these and found that their extents of adsorption onto the spherical activated carbon material were nearly identical. The amount of adsorption was approximately 1.4 mg·g^-1 for urea, 18 mg·g^-1 for creatinine, and 20 mg·g^-1 for uric acid. The urea, creatinine, and uric acid adsorbed onto the spherical activated carbon decomposed on heat treatment at 500℃, and the adsorption capacity of the spherical activated carbon was regenerated. Our study successfully demonstrated that the spherical activated carbon can be recycled in the waste dialysate treatment process.     

Influence of ammonium salt on electrowinning of copper from ammoniacal alkaline solutions

In order to develop an energy-saving copper recycling process from wastes, electrochemical measurements were conducted in ammoniacal alkaline solutions containing Cu(I) ions and an ammonium salt of sulfate, chloride or nitrate. The results of each system were then compared. The polarization measurements suggested that the voltage required for the electrode process is lower in the chloride and nitrate systems than that in the sulfate system. The cathode current efficiency during the copper electrodeposition varied from 39 to 97% and increased with current density in the chloride and sulfate systems. In the nitrate system, the lowest cathode current efficiency of 30% was observed because of nitrate ion reduction. Based on these results, the power consumption required for the electrowinning stage of the copper recycling process was calculated. Among these three systems, the chloride system showed the lowest power consumption of 500 kWh t⁻¹ at the current density of 200 A m⁻², which is about 25% of the conventional copper electrowinning process from a copper sulfate-sulfuric acid solution.     

Conformational studies of poly(N-methyl-l-alanine) by n.m.r. spectroscopy

Nuclear magnetic resonance (n.m.r.) and circular dichroism of $\text{poly}\text{(N-}\text{methyl-}\text{l}\text{-alanine}\text{)}$ in methylene $\text{chloride}\text{-d}{}_2\text{dichloroacetic acid}$ were investigated. In methylene chloride-d₂$\text{poly}\text{(N-}\text{methyl-}\text{l}\text{-alanine}\text{)}$ was found to consist of nearly all-trans amide bonds and assume a stable secondary structure. Trace amounts of cis amide bonds were also present. The addition of dichloroacetic acid destroyed the secondary structure and induced a drastic change of the n.m.r. spectrum, which was similar to that observed with the monomeric amide, $\text{N-}\text{acetyl}\text{-N-}\text{methyl-}\text{l}\text{-alanine}$ dimethylamide. In comparison of the polymer with the monomeric amide, it was concluded that the transition of $\text{poly}\text{(N-}\text{methyl-}\text{l}\text{-alanine}\text{)}$ was caused by the isomerization of amide bonds. The complex n.m.r. spectrum was interpreted in terms of the distribution along the polymer chain of various non-planar amide links as well as planar cis and trans amide links. The difference of the mechanism of conformational transition between poly(amino acid) and poly(imino acid) is also discussed.     

Discussions of worker ants’ rule-based CHC dealing with changing environments

Contrary to popular belief, biologists discovered that worker ants are really not all hardworking. It has been found that in three separate 30-strong colonies of black Japanese ants (Myrmecina nipponica), about 20% of worker ants are diligent, 60% are ordinary, and 20% are lazy. That is called 20:60:20 rule. Though they are lazy, biologists suggested that lazy worker ants could be contributing something to the colony that is yet to be determined. In our last research, we used CHC (cross generational elitist selection, heterogeneous recombination, and cataclysmic mutation) with the worker ants’ rule (WACHC) aiming at solving optimization problems in changing environments. CHC is a nontraditional genetic algorithm (GA) which combines a conservative selection strategy that always preserves the best individuals found so far with a radical (highly disruptive) recombination operator. In our last research, we verified that WACHC performs better than CHC in only one case of fully changing environment. In this paper, we further discuss our proposed WACHC dealing with changing environment problems with varying degree of difficulty, compare our proposal with hypermutation GA which is also proposed for dealing with changing environment problems, and discuss the difference between our proposal and ant colony optimization algorithms.     

Morphological characteristics of flood refugia of cobble-bed vegetation

Periodic flooding alters riverine vegetation community composition; moderate flood disturbance maintains communities at an early seral stage, whereas severe floods may remove entire communities. After disturbance, plants may recolonize riverbeds from refugia.Here, we investigated the morphological characteristics of refugia where riverine plants survived large floods. At three sites, plant communities growing on cobble-bars were surveyed, and the hydraulic characteristics of each site were analyzed. The populations of an indicator plant, Anaphalis margaritacea sub-species yedoensis (Franch. et Savat.) were assessed after major floods in 2004 and 2009. At each survey, the particle size and bed composition were measured, and the critical shear-stress required to move particles at each site was calculated. A one-dimensional flow and the average and local shear-stress at ten different discharges, including that of the largest flood were calculated. The results demonstrate that the A. margaritacea community is maintained at locations where the local shear-stress at peak discharge in large-floods does not exceed a critical value. These conditions were achieved in locations with particular morphological characteristics, where the river is not constrained by levees and is restricted by a downstream narrow-pass; in this reach river width increases with discharge thus limiting the increase in water depth with increasing discharge and allowing the establishment of refugia where plant species may survive large floods.Flooding and reestablishment from refugia maintain a characteristic riverbed community in equilibrium.     

粉末冶金结构零件材料的泊松比

研究了粉末冶金机械零件使用的烧结材料的杨氏模量、切变模量及泊松比与孔隙度的关系.制备了三种钢粉,在不同条件下进行了压制、烧结与热处理.孔隙度对杨氏模量、切变模量及泊松比的影响最大.特别是泊松比还受孔隙形状的影响,而孔隙形状随粉末类型、烧结温度与烧结气氛及热处理条件而变化.对于大部分实际应用的粉末组成来说,烧结气氛对经烧结和热处理后材料的泊松比影响不大.对于部分预合金化粉末(Fe4%Ni1.5%Cu0.5%Mo)+0.8%石墨,只有在孔隙度低于20%时,烧结温度对泊松比与孔隙度的关系才有影响.在这种情况下.提出了烧结与热处理试样泊松比与孔隙度关系的较简单近似方程:在烧结温度1 423K下,v=0.300-0.266P+0.579P2;在烧结温度1 523K下,v=0.304-0.264P+0.548P2.     

Swarm robotic network using Lévy flight in target detection problem

One approach in swarm robotics is homogeneous system which is embedded with sensing, computing, mobile and communication components. In this study, a target detection problem, which is one of navigation problems, was employed. Once a robot detects a target, robots immediately communicate with a base station via intermediate relay robots due to the multi-hop transmission of wireless communication. Therefore, this control task is completed with connectivity of the network. In a target detection problem, we must improve the performance of exploration as well as connectivity of the network. This study investigates the performances of the two types of random walk algorithm in navigation while loosely ensuring connectivity of the robotic network based on our previous study.     

Effect of skimmed milk and its fractions on the inactivation of Escherichia coli K12 by high hydrostatic pressure treatment

We investigated the effects of skimmed milk and its protein fractions (casein, whey, globulin, and albumin) on the injury and inactivation of Escherichia coli K-12 by high hydrostatic pressure (HHP) treatment. The protective effect of skimmed milk on HHP-mediated inactivation and injury of E. coli increased with increases in the skimmed milk concentration. However, protein fractions derived from skimmed milk did not exhibit this protective effect. Microscopy analysis by DAPI/PI staining indicated that some cells were localized in the solid portion of skimmed milk, and some of these cells were alive. The coagulated fraction derived from the autoclaved whey fraction also showed a significant protective effect. We speculate that the solid portion in skimmed milk could provide the protective effect to bacterial cells.     

Keratanase II-catalyzed synthesis of keratan sulfate oligomers by using sugar oxazolines as transition-state analogue substrate monomers: a novel insight into the enzymatic catalysis mechanism

Keratan sulfate (KS) oligomers with well-defined structures were synthesized by keratanase II (KSase II)-catalyzed transglycosylation. N-Acetyllactosamine [Galbeta(1-->4)GlcNAc; LacNAc] oxazoline derivatives with sulfate groups at the C-6 (1 a) and both the C-6 and the C-6' (1 b) were prepared as transition-state analogue substrate monomers for KSase II. Monomer 1 a was effectively oligomerized by the enzyme under weak alkaline conditions, to give alternating 6-sulfated KS oligomers (2 a) in good yields, and with total control of regioselectivity and stereochemistry. KSase II also recognized 1 b, which provided fully 6-sulfated KS oligomers (2 b) in good yields under similar conditions. Nonsulfated LacNAc oxazoline was difficult to oligomerize enzymatically. These results imply that the catalysis mechanism of KSase II involves a sugar oxazolinium ion that requires the 6-sulfate group in the GlcNAc residue not only in hydrolysis of KS chains, but also in oligomerization of oxazoline monomers. This is the first report of KSase II-catalyzed transglycosylation to form beta(1-->3)-glycosidic bond through a substrate-assisted mechanism.     

Multifunctional Composites of Chiral Valine Derivative Schiff Base Cu(II) Complexes and TiO2

We have prepared four new Cu(II) complexes containing valine moieties with imidazole ligands at the fourth coordination sites and examined their photo-induced reactions with TiO₂ in order of understanding the reaction mechanisms. Under a nitrogen atmosphere, the intermolecular electron transfer reactions (essentially supramolecular interactions) of these systems, which resulted in the reduction of Cu(II) species to Cu(I) ones, occurred after UV light irradiation. In this study, we have investigated the conditions of the redox reactions in view of substituent effects of aldehyde moieties. The results of cyclic voltammetry (CV) on an rotating ring-disk electrode (RRDE) suggested that the substitution effects and redox potentials were correlated. Density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations were also performed to simulate the UV–Vis and circular dichroism (CD) spectra; the results revealed a reasonably good correlation between the substituent effects and the highest occupied molecular orbitals and the lowest unoccupied molecular orbitals (HOMO-LUMO) gaps associated with the most intense transition bands. In addition, we summarized the substitution effects of Cu(II) complexes for their corresponding UV light-induced reactions.