Development of a novel glue consisting of naturally-derived biomolecules: citric acid and human serum albumin

A novel glue consisting of human serum albumin (HSA) and citric acid derivative (CAD) was developed where the glue is named as CAD-A glue. In this adhesive, CAD works as a crosslinking reagent of HSA. For preparing crosslinking reagent CAD, using citric acid as a starting material, three carboxyl groups of a citric acid were modified with N-hydroxysuccinimide in the presence of 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide hydrochloride. From 1H-NMR spectrum, CAD with three active ester groups in a molecule was successfully synthesized with a high yield (more than 80%). The boding time of CAD-A glue to collagen-based casing was saturated within 15 minutes. The bonding strength of this glue to collagen-based casings increased with increasing of HSA concentration. The maximum bonding strength of CAD-A glue was a slightly low level compared to the bonding strength of cyanoacrylate adhesive and was 9 times higher than that of fibrin glue. The CAD-A glue showed excellent biocompatibility and high ability of wound closure similar to that of cyanoacrylate-based adhesive when glues were applied to the mouse skin. These results suggested that this developed adhesive had both tissue compatibility and bonding strength for use in clinical field.     

Adsorption characteristics of clay adsorbents – sepiolite,kaolin and synthetic talc – for removal of Reactive Yellow 138:1

Adsorption characteristics of three clay adsorbents – sepiolite, kaolin and synthetic talc – were investigated to determine their applicability to remove an anionic reactive dye – Reactive Yellow 138:1 – from a water stream. Results showed that synthetic talc had the highest maximum monolayer adsorption capacity of 10.07 mg/g, followed by kaolin (3.73 mg/g) and sepiolite (3.23 mg/g), for the removal of Reactive Yellow 138:1. Synthetic talc and sepiolite removed dyes from aqueous solutions mainly through physical adsorption depending on the surface area. By contrast, the adsorption mechanism of kaolin was strongly influenced by the anion exchange mechanism. Zeta potential analysis revealed that the adsorption capacity of clay adsorbents increased under acidic rather than alkaline conditions, owing to protonation of the clay surface. Moreover, synthetic talc was successfully regenerated by heating at more than 400°C, effectively restoring its original adsorption capacity.     

Improvement in Thermoelectric Properties of Se-Free Cu3SbS4 Compound

Recently, Cu-based chalcogenides such as Cu₃SbSe₄, Cu₂Se, and Cu₂SnSe₃ have attracted much attention because of their high thermoelectric performance and their common feature of very low thermal conductivity. However, for practical use, materials without toxic elements such as selenium are preferable. In this paper, we report Se-free Cu₃SbS₄ thermoelectric material and improvement of its figure of merit (ZT) by chemical substitutions. Substitutions of 3 at.% Ag for Cu and 2 at.% Ge for Sb lead to significant reductions in the thermal conductivity by 37% and 22%, respectively. These substitutions do not sacrifice the power factor, thus resulting in enhancement of the ZT value. The sensitivity of the thermal conductivity to chemical substitutions in these compounds is discussed in terms of the calculated phonon dispersion and previously proposed models for Cu-based chalcogenides. To improve the power factor, we optimize the hole carrier concentration by substitution of Ge for Sb, achieving a power factor of 16 μW/cm K² at 573 K, which is better than the best reported for Se-based Cu₃SbSe₄ compounds.     

Defining the Interaction of Human Soluble Lectin ZG16p and Mycobacterial Phosphatidylinositol Mannosides

ZG16p is a soluble mammalian lectin that interacts with mannose and heparan sulfate. Here we describe detailed analysis of the interaction of human ZG16p with mycobacterial phosphatidylinositol mannosides (PIMs) by glycan microarray and NMR. Pathogen‐related glycan microarray analysis identified phosphatidylinositol mono‐ and di‐mannosides (PIM1 and PIM2) as novel ligand candidates of ZG16p. Saturation transfer difference (STD) NMR and transferred NOE experiments with chemically synthesized PIM glycans indicate that PIMs preferentially interact with ZG16p by using the mannose residues. The binding site of PIM was identified by chemical‐shift perturbation experiments with uniformly ¹⁵N‐labeled ZG16p. NMR results with docking simulations suggest a binding mode of ZG16p and PIM glycan; this will help to elucidate the physiological role of ZG16p.     

Residues of total mercury and methyl mercury in eel products

Fifty-two samples of broiled eels and broiled eel liver were analyzed for total mercury (total Hg) and methyl mercury. The mean concentrations of total Hg in broiled eels and broiled eel liver were 0.21 ppm and 0.10 ppm, respectively. Meanwhile, the mean concentrations of methyl mercury in broiled eels and broiled eel liver were 0.085 ppm and 0.039 ppm, respectively. The rate of methyl mercury to total Hg mainly ranged from 60 to 80% in broiled eels and from 35 to 65% in broiled eel liver. The total Hg concentrations of 2 samples of broiled eels and one sample of broiled eel liver exceeded the provisional regulation limit (0.4 ppm) of total Hg in fish in Japan. In these samples, the rates of methyl mercury to total Hg were lower than 20%. The muscles and the skin of broiled eels were measured separately. The ratios of skin to muscle concentration of total Hg and methyl mercury were mainly in the range from 1/10 to 1/4. The mean intakes of total Hg from broiled eels and broiled eel liver per individual were 24.6 microg and 3.1 microg, respectively. The mean intakes of methyl mercury from broiled eels and broiled eel liver per individual were 10.4 microg and 1.2 microg, respectively.     

Wetting and reaction between Si droplet and SiO<Subscript>2</Subscript> substrate

The wetting and reaction between Si melt and SiO₂ substrate were investigated as a function of the atmosphere, temperature, and degree of vacuum. The results revealed that below 2 Torr with an Ar flow, the wetting angle is finally 90°. The Si droplet was stationary at a wetting angle of 90°. Videos indicated that the droplets moved and vibrated; Above 20 Torr, the Si droplet vibrated up and down with a frequency of approximately 2 Hz, thereby changing the wetting angle. Further, the droplet remained stationary on a substrate on which grooves with a width of 100 μm and depth of 100 μm were etched with a pitch of 1 mm. The presence of grooves or dimples on the substrates facilitated the leakage of SiO gas; as a result, the Si droplet did not vibrate. A vibration model was proposed in which the SiO gas produced at the interface between the Si droplet and the substrate according to the reaction Si + SiO = 2SiO expands and leaks continuously.     

Experimental Study and Finite Element Polycrystal Model Simulation of the Cold Rolling Textures in a Powder Metallurgy Processed Pure Aluminum Plate

Ingot metallurgy (IM) aluminum has long been the subject and attracted the attention of many metallurgists and textural researchers of materials. Due to the introduction of large amounts of ex situ interfaces, however, the textures in powder metallurgy (PM) processed aluminum has been rarely reported. In this article, a pure aluminum plate was prepared via PM route. The starting billet was first produced with uni-axially cold compaction and flat hot-extrusion and then followed by cold rolling processes. The hot-extruded and cold rolling deformation textures of the pure PM aluminum at 50%, 80% and 90% cold rolling reductions were studied by orientation distribution functions (ODFs) analysis. The finite element polycrystal model (FEPM) was finally utilized to simulate the cold rolling textural     

Host-Guest Complexation Strategy for Passivating Pb-Dimer Related Defects in Perovskite Photovoltaics

Although there is extensive attention to the eminent perovskite solar cells, the deep-level defects such as Pb-Pb dimers in the solution-processed polycrystalline perovskites inevitably result in photovoltaic output losses and subsequent degradation. Recently, it is reported that an electron-donating group can passivate Pb dimer defects efficiently. However, the mechanism for the causation of metallic lead (Pb⁰) from the iodide vacancy (V_I) is unclear. Herein, a chain reaction mechanism is proposed for the possible transformation process from V_I to Pb⁰ with the Pb dimer intermediates. In this regard, a host-guest strategy is adopted by using 4-tert-Butyl-1-(ethoxycarbonyl- methoxy) thiacalix[4]arene (tBuTCA) to complex with the cations and out-of-cage (Lead(II) iodide) PbI₂. Moreover, a host-guest complexation can be formed due to the Pb²⁺-π interactions. Continuously, the negative charge compensation for iodine vacancy can hinder the formation of Pb-Pb dimer, thus significantly suppressing non-radiative recombination. Consequently, the resulting solar cells show more than 24% power conversion efficiencies and maintain over 96% of their initial performance without encapsulation for 486 h under an ambient environment. This work highlights the significance of supramolecular engineering in constructing a high-quality perovskite for efficient and stable perovskite solar cells.