Mechanisms of gold recovery from aqueous solutions using a novel tannin gel adsorbent synthesized from natural condensed tannin

We report a novel recovery system for gold (Au), which is one of the precious metals contained in electronic scrap, utilizing tannin gel particles. Tannin gel particles were prepared by a process of cross-linking of condensed tannin (wattle tannin), which is a ubiquitous and inexpensive natural material having many hydroxyl groups. The adsorption mechanism of gold onto tannin gel particles was elucidated: the adsorption of gold takes place through the reduction of trivalent gold ions to metallic gold on the surface of tannin gel particles, which is accompanied by the simultaneous oxidization of the hydroxyl groups of tannin gel. Additionally, the adsorption capacity of gold was found to be extremely high, 8000 mg-Au/g-dry gel. The outstanding characteristics of tannin gel particles for gold offers the possibility of efficient recovery of other precious metals.     

Identification of a New Diterpene Biosynthetic Gene Cluster that Produces O‐Methylkolavelool in Herpetosiphon aurantiacus

Diterpenoids are usually found in plants and fungi, but are rare in bacteria. We have previously reported new diterpenes, named tuberculosinol and isotuberculosinol, which are generated from the Mycobacterium tuberculosis gene products Rv3377c and Rv3378c. No homologous gene was found at that time, but we recently found highly homologous proteins in the Herpetosiphon aurantiacus ATCC 23779 genome. Haur_2145 was a class II diterpene cyclase responsible for the conversion of geranylgeranyl diphosphate into kolavenyl diphosphate. Haur_2146, homologous to Rv3378c, synthesized (+)‐kolavelool through the nucleophilic addition of a water molecule to the incipient cation formed after the diphosphate moiety was released. Haur_2147 afforded (+)‐O‐methylkolavelool from (+)‐kolavelool, so this enzyme was an O‐methyltransferase. This new diterpene was indeed detected in H. aurantiacus cells. This is the first report of the identification of a (+)‐O‐methylkolavelool biosynthetic gene cluster.     

Simple and Efficient Profiling of Phospholipids in Phospholipase D-modified Soy Lecithin by HPLC with Charged Aerosol Detection

Dietary phosphatidylinositol (PI) can be synthesized via phospholipase D (PLD)-catalyzed transphosphatidylation of phosphatidylcholine (PC), abundant in soy lecithin, with myo-inositol. However, a generated mixture of phospholipid (PL) classes poses a challenge for analysis. Our current work on Streptomyces PLD engineering requires a robust analytical method for profiling of PI and related PLs derived from the transphosphatidylation reactions. Therefore, we optimized an HPLC-based method with charged aerosol detector (CAD) for PL quantification. PLs were separated on a normal phase silica column by a gradient elution system using two solvents containing chloroform/methanol/1 M formic acid–triethylamine buffer in different ratios. Retention times of the PL standards and LC–MS under identical conditions were used to identity PL classes. PL standards gave linear response in 100- and 10-fold (lyso-PI) concentration range. The method provided a simple, sensitive, repeatable, and precise analysis of PI, PC, phosphatidylethanolamine, phosphatidic acid, and lyso forms of PC and PI. Compared to the similar existing method, introduction of CAD provided a three- to fivefold decrease at the lower end and a two- to fivefold increase at the upper end of the dynamic range. High precision, high sensitivity, and low limits of detection and quantification further underline the benefits of CAD in PL analysis.     

A simple and rapid method for histamine analysis in fish and fishery products by TLC determination

A simple and rapid thin-layer chromatography (TLC)-densitometry method for histamine analysis in fish and fishery products was established. Histamine was extracted from seafood with 80% ethanol. The sample extracts and standard solutions of histamine were applied to cellulose TLC plate and developed by ascending chromatography with ammonia–ethanol 1:3 (v/v) as mobile phase. Histamine was visualized with pauly’s reagent, the intensity of the colored spots was digitized and calculated by image processing method software, Lane & Spot Analyzer (ATTO, Tokyo, Japan). Successful separation of histamine from other (imidazole compounds) pauly’s reagent-positive components in 80% ethanol fish extracts was achieved. The linearity of the histamine estimation using this method was good within the range from 30 ng to 1000 ng of histamine (r² = 0.9997). Histamine can be satisfactorily detected and completely separated from histidine, 4-methyl-imidazole and other pauly’s reagent-positive compounds. This method does not need expensive instrument, any tedious pretreatment to eliminate potential interference other imidazole compounds such as histidine or carnosine. It is also less reagents compared with HPLC method. Moreover, it is a simple, rapid, sensitive, reproducible. Therefore this method is suitable for monitor of histamine in multiple fish and fishery products simultaneously that contain as little as 20 ppm histamine (2.0 mg/100 g).     

Magnetic properties of PLD‐fabricated ND‐Fe‐B film magnets and their applications to millimeter‐size motors

We succeeded in depositing 200‐ to 300‐µm‐thick Nd‐Fe‐B film magnets with (BH)_max of approximately 55 kJ/m³ on Fe substrates by the PLD method. In addition, we confirmed that a millimeter‐size motor, which was prepared from the obtained film, rotates at 15,160 rpm under a no‐load test. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 159(2): 1–6, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20215     

Diosgenin attenuates inflammatory changes in the interaction between adipocytes and macrophages

Obese adipose tissues are characterized by the enhanced infiltration of macrophages. It is considered that the paracrine loop involving monocyte chemoattractant protein‐1, tumor necrosis factor‐α, and the free fatty acid between adipocytes and macrophages establishes a vicious cycle that aggravates inflammatory changes and insulin resistance in obese adipose tissues. Diosgenin, a saponin aglycon found in a variety of plants, has anti‐inflammatory properties. In the present study, we examined the effect of diosgenin on the inflammatory changes in the interaction between adipocytes and macrophages. A coculture of 3T3‐L1 adipocytes and RAW 264 macrophages markedly enhanced the production of tumor necrosis factor‐α, monocyte chemoattractant protein‐1, and nitric oxide compared with the sum of their single cultures; however, treatment with diosgenin inhibited the production of these proinflammatory mediators. Diosgenin also suppressed the inflammation in RAW 264 macrophages that was induced by the conditioned medium derived from 3T3‐L1 adipocytes. Furthermore, diosgenin inhibited the conditioned medium‐induced degradation of inhibitor κB and the phosphorylation of c‐jun N‐terminal kinase in macrophages. These results indicate that diosgenin exhibits anti‐inflammatory properties in the interaction of adipocytes and macrophages by inhibiting the inflammatory signals in macrophages. Diosgenin may be useful for ameliorating the inflammatory changes in obese adipose tissues.     

Relationship Between Tactile Sensation and Friction Signals in Cosmetic Foundation

A tribometer was developed to simulate friction phenomena occurring when human fingers are rubbed together in order to acquire the tactile sensation of applying cosmetic foundation. The tribometer utilizes silicone–rubber surfaces with compliance comparable to that of human fingerpads; these surfaces are lubricated by 10 types of samples simulating cosmetic foundation. To characterize the samples, seven types of feature quantities are introduced from friction signals acquired in three types of sliding tests. The relationship between feature quantities and tactile sensation was investigated using a multiple regression analysis; resulting equations show some level of agreement with the score of a sensory assessment vis-à-vis five types of tactile sensation. The results indicate that static and kinetic frictions are not always dominant factors in determining the comfort of tactile sensation in applying cosmetic foundation.     

Dynamics of Consolidation and Crack Growth in Nanocluster-Assembled Amorphous Silicon Nitride

Consolidation and fracture dynamics in nanophase amorphous Si3N4 are investigated using 106-atom molecular-dynamics simulations. At a pressure of 15 GPa and 2000 K, the nanophase system is almost fully consolidated within a fraction of a nanosecond. The consolidation process is well-described by the classical theory of sintering. Under an applied strain the consolidated system develops several cracks which propagate parallel to each other, causing failure at multiple sites. The critical strain at which the nanophase system fractures is much larger than that for crystalline Si3N4.     

Consideration of Particle Swarm Optimization combined with tabu search

This paper presents a new form of Particle Swarm Optimization (PSO) based on the concept of tabu search (TS). In PSO, when a particle finds a local optimal solution, all of the particles gather around that one, and cannot escape from it. On the other hand, TS can escape from the local optimal solution by moving away from the best present solution. The proposed Tabu List PSO (TL‐PSO) is a method for combining the strong points of PSO and TS. This method stores the history of pbest in a tabu list. When a particle has a reduced searching ability, it selects a pbest of the past from the historical values, which is used for the update. This makes each particle active, and the searching ability of the swarm makes progress. The proposed method was validated by numerical simulations with several functions that are well known as optimization benchmark problems for comparison to the conventional PSO method. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 172(4): 31–37, 2010; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20966     

Investigation of vibrotactile sensation of human fingerpads by observation of contact zones

An experimental apparatus has been developed to observe the contact zones between human fingerpads and a smooth flat surface of a total-reflection prism. Using this apparatus, the following experiments have been carried out: (1) measurement of the apparent and real contact areas of fingerpads under a controlled contact load, (2) measurement of the vibrotactile thresholds of fingerpads under a controlled contact load, and (3) investigation of the discrimination of tones by tactile sensation under a controlled contact load. From the third experiment, it is found that human fingerpads can discriminate between tones from the differences in their harmonic components.