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Cellulose fibers have been one of the most common fibers due to their biodegradability, excellent mechanical properties, biocompatibility, high absorption ability, cheapness and renewability. In this study, novel, simple and green method is concerned with the production of multifunctional cellulose nanofibers (CNFs). Nanocomposites consisting of silver nanoparticles (AgNPs) and polyaniline (PANi) were in situ synthesized into plasma-pretreated cellulosic nanofibers fabricated by solution blowing spinning technique. The produced cellulose acetate nanofibers were then subjected to deacetylation followed by plasma-activation followed by a treatment with aniline and silver nitrate (AgNO3) in the presence of ammonium acetate. Plasma-assisted oxidation polymerization process of aniline into PANi associated with a reduction of Ag+ into AgNPs results in their permanent insolubility into the surface of the cellulose nanofibers. The morphologies and elemental contents were determined by polarizing optical microscope (POM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), energy-dispersive X-ray patterns and scanning electron microscopy (SEM). Additionally, transmission electron microscope (TEM) was applied to explore the morphologies of silver nanoparticles and PANi showing particle diameter between 12 and 25 nm. The antimicrobial Ag NPs were formed from an aqueous medium of silver nitrate by taking the reduction ability advantage of the electrically active PANi. The immobilization of polyaniline and silver nanoparticles into the surface of the cellulose nanofibers enhanced its electrical conductivity. The produced CNFs demonstrated a high UV protection as well as antibacterial activity.

Complex [Cu(phen)2Cl]Cl∙2PABA∙4H2O has been isolated, where phen ligand is 1,10-phenanthroline and PABA is p-aminobenzoic acid. The complex crystallizes in the centrosymetric (monoclinic) space group P2(1)/n. The unit cell dimensions are a = 10.479(4) A, b = 22.396(7) A, and c = 16.212(6) A. The basic unit structure of complex is distorted trigonal bipyramidal. Two hydrogen-bonded PABA molecules are enclosed through π−π interactions in filled aryl box FAB motif made by juxtaposition of four phen from two opposing cations. While π−π interaction between phen causes the formation of offset face-to-face overlap OFF primary motif. The result is formation of extended (OFF-FAB)n chains. Cyclic voltammetry showed one reversible oxidation reduction process followed by one irreversible oxidation process. Thermal analysis indicated successive loss of crystalline water and crystalline PABA molecules, chloride ions, and phen ligands. DFT study indicates that PABA interacts with phen with binding energy 68.87 kJ mol−1 reflecting strong π-stacking. The charge density in HOMO is localized on the metal halogen bond, whereas in LUMO, it is spread over two phen. The vibrational spectrum of complex was calculated at M05-2X/6-31G(d) and compared with the experimental vibrational spectrum data. The inhibitory concentrations IC50 against carcinoma cells A549 (lung adenocarcinoma) and MDA-MB-231 (breast adenocarcinoma) are 3.4 and 4.5 µM, respectively. IC50 values of new complex are comparable to those of cisplatin and smaller than the values for [Cu(phen)2Cl]Cl∙6.5H2O.

The amount of hydrogen gas generated from metal oxide materials, based on a thermochemical water-splitting method, gradually reduces as the surface of the metal oxide oxidizes during the hydrogen generation process. To regenerate hydrogen, the oxygen reduction process of a metal oxide at high temperatures (1000–2500 °C) is generally required. In this study, to overcome the problem of an energy efficiency imbalance, in which the required energy of the oxygen reduction process for hydrogen regeneration is higher than the generated hydrogen energy, we investigated the possibility of the oxygen reduction of a metal oxide with a low energy using microwave irradiation. For this purpose, a macroporous nickel-oxide structure was used as a metal oxide catalyst to generate hydrogen gas, and the oxidized surface of the macroporous nickel-oxide structure could be reduced by microwave irradiation. Through this oxidation reduction process, ∼750 μmol g−1 of hydrogen gas could be continuously regenerated. In this way, it is expected that oxygen-enriched metal oxide materials can be efficiently reduced by microwave irradiation, with a low power consumption of

A new 1:1 alternating copolymerization of a five-membered, six-membered, and seven-membered cyclic germylene having a Me3Si-N group with N-phenyl-p-quinoneimine has successfully been demonstrated. The germylenes behaved as a reductant monomer whereas N-phenyl-p-quinoneimine as an oxidant monomer to give copolymers (oxidation-reduction copolymerization). In contrast to the previous observation that the copolymerization of cyclic germylenes with p-benzoquinone led to the formation of 2:1 periodic copolymers, the present copolymerization using a p-quinoneimine derivative produces all 1:1 alternating copolymers.

Quorum sensing is a cell-cell communication mechanism mediated by chemical signals that leads to differential gene expression in response to high population density. Salmonella is unable to synthesize the autoinducer-1 (AI-1), N-acyl homoserine lactone (AHL), but is able to recognize AHLs produced by other microorganisms through SdiA protein. This study aimed to evaluate the fatty acid and protein profiles of Salmonella enterica serovar Enteritidis PT4 578 throughout time of cultivation in the presence of AHL. The presence of N-dodecanoyl-homoserine lactone (C12-HSL) altered the fatty acid and protein profiles of Salmonella cultivated during 4, 6, 7, 12 and 36 h in anaerobic condition. The profiles of Salmonella Enteritidis at logarithmic phase of growth (4 h of cultivation), in the presence of C12-HSL, were similar to those of cells at late stationary phase (36 h). In addition, there was less variation in both protein and fatty acid profiles along growth, suggesting that this quorum sensing signal anticipated a stationary phase response. The presence of C12-HSL increased the abundance of thiol related proteins such as Tpx, Q7CR42, Q8ZP25, YfgD, AhpC, NfsB, YdhD and TrxA, as well as the levels of free cellular thiol after 6 h of cultivation, suggesting that these cells have greater potential to resist oxidative stress. Additionally, the LuxS protein which synthesizes the AI-2 signaling molecule was differentially abundant in the presence of C12-HSL. The NfsB protein had its abundance increased in the presence of C12-HSL at all evaluated times, which is a suggestion that the cells may be susceptible to the action of nitrofurans or that AHLs present some toxicity. Overall, the presence of C12-HSL altered important pathways related to oxidative stress and stationary phase response in Salmonella.

In the late stage of anthocyanin biosynthesis, dihydroflavonol reductase (DFR) and anthocyanidin synthase (ANS) mediate a formal tautomerization. However, such oxidation/reduction process requires high energy and appears to be unnecessary, as the oxidation state does not change during the transformation. Thus, a non-enzymatic pathway of tautomerization has also been proposed. To resolve the long-standing issue of whether this non-enzymatic pathway is the main contributor for the biosynthesis, we carried out density functional theory (DFT) calculations to examine this non-enzymatic pathway from dihydroflavonol to anthocyanidin. We show here that the activation barriers for the proposed non-enzymatic tautomerization are too high to enable the reaction to proceed under normal aqueous conditions in plants. The calculations also explain the experimentally observed requirement for acidic conditions during the final step of conversion of 2-flaven-3,4-diol to anthocyanidin; a thermodynamically and kinetically favorable concerted pathway can operate under these conditions.

In the process of hot dip galvanizing high tensile strength sheet steels containing Si and Mn, selective surface oxidation of Si and Mn causes coating defects. One promising method for overcoming this problem is an oxidation-reduction process. When the steel surface is exposed to an oxidizing atmosphere, it will react primarily by forming an Fe oxide, which can be reduced by hydrogen in a reduction process that follows. It has been explained that good wettability can be obtained due to the formation of pure iron. However, the mechanism of suppression of selective surface oxidation has not been clearly understood in detail yet. In order to reveal this mechanism, the present study focused on both Mn and Fe oxidation behavior during the oxidation-reduction process for a cold-rolled sheet steel containing 0.25mass%Si-1.8mass%Mn. Surface and cross-sectional analyses were performed by using secondary electron microscopy and transmission electron microscopy. Selective surface oxidation behavior was investigated by glow discharge optical emission spectroscopy. The main results obtained are as follows. First, selective surface oxidation of Mn was suppressed even if soaking was continued after completion of the reduction of the Fe oxide. Second, as the reduction process proceeded, Mn was trapped as an internal oxide under the Fe oxide layer. Moreover, depletion of solute Mn was observed in the matrix. From these results, depletion of solute Mn is supposed to suppress the outer diffusion of Mn during soaking. Therefore, selective surface oxidation of Mn is suppressed even after Fe oxide reduction is completed.

An improved Cu-Cu joint strength was achieved by a pressureless sintering bonding using microscale Cu particles with an oxidation-reduction process for power device packaging. After the bonding at 300 °C in air, Cu2O nanoparticles uniformly formed on the surface of microscale Cu particles through a thermal oxidation, and the formation of neck between microscale Cu particles was obvious. Then, after the following bonding at 300 °C in a reductive formic acid atmosphere, the Cu2O nanoparticle surface of microscale Cu particles was reduced to a Cu nanostructured surface, meanwhile the joining between the microscale Cu particles was facilitated by formed nanostructured surface, resulting a higher joint strength than that of the bonding joint with entire formic acid atmosphere process. The results demonstrate that the pressureless sintering bonding using microscale Cu particles by the oxidation-reduction process has the potential to fulfill the requirement of die-attach bonding for power device packaging.

Aligned multi-walled carbon nanotubes (MWCNTs) were synthesized directly on a stainless steel surface by surface activation by intense oxidation in air followed by a moderate reduction in H 2 without any wet process. This method is extremely simple compared with conventional ways that need catalyst loading steps or acid pre-etching steps to synthesize carbon nanotubes on stainless steel surfaces. It was found that the length of MWCNT bundles could reach 80 μm when the oxidation step was properly controlled. It was demonstrated that MWCNTs synthesized on stainless steel meshes could be used as a catalyst support to enhance ozone oxidation in the decomposition of phenol in water.

Voltametrically stable 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS2−) modified electrode was obtained by sol–gel processing of methyltrimethoxysilane based sol with dissolved ABTS2− together with dispersed graphite particles. Next, extracellular laccase from Cerrena unicolor was encapsulated within a thin hydrophilic tetramethoxysilane film on the top the electrode. The obtained ABTS2− modified carbon ceramic electrode exhibits stable voltammetry corresponding to the surface confined oxidation reduction process. The biocatalytic activity of this electrode is similar to that observed when ABTS2− is present in solution. Keywords: Laccase, ABTS, Dioxygen reduction, Sol–gel, Carbon ceramic electrode, Bioelectrocatalysis

Samples were obtained at 26 stations in five cross-shelf transects in the East China Shelf-Sea for the determination of iodate and iodide. The upwelling water at the shelf-edge at 25.5°N was characterized as a dome of subsurface, cold ( 6 μM), R-iodate-rich (>0.35 μM) and R-iodide-poor ( 5. (R-iodate and R-iodide were the concentrations of iodate and iodide normalized to a salinity of 35.) The upwelling water could be traced farthest away from its source region by the iodine species. They indicate that upwelling occurred at discrete upwelling centers at the shelf edge. Aside from the upwelling center at 25.5°N, a second center was found at 27°N as suggested in recent modeling exercises. Upwelling water was present along the entire length of the outer shelf in the study area from 25°N to 29°N. Its shoreward intrusion across the shelf was more extensive in the southern part of the Shelf-Sea where it reached the middle shelf. At the sea surface, the upwelling water could be detected as a continuous band of water, with low R-iodide ( 0.3 μM) and high iodate/iodide (>2.5), which traversed along the entire length of the middle/outer shelf. Thus, the influence of the upwelling water in the Shelf-Sea was more pervasive than what would be construed from the distributions of temperature and nitrate alone. High surface concentrations of dissolved organic iodine, DOI, were associated with the plume of Changjiang Diluted Water along the Chinese coast. While the changes in the concentrations of iodate in the surface waters could not be accounted for by the reduction of iodate to iodide alone, they could be largely explained when the conversion of iodate to DOI was also allowed. In box modeling exercises, the geochemical dynamics of the iodine system in the East China Sea Shelf system were qualitatively independent of the magnitude of the transport of the Taiwan Strait Warm Water used. Within the probable range of up to 1 Sv, invariably, iodate was consumed and iodide was produced in the system. The accompanying net export of iodide to the adjoining Kuroshio and the Japan Sea was 1(±0.5)×10 9 mol/year. Thus, marginal seas may act as a preferred site for the reduction of iodate to iodide and as a net source of iodide to the ocean interior. The production of iodide accounted for only 40(±10)% of the consumption of iodate, suggesting that iodate was converted not only to iodide but also to other forms of iodine in the Shelf system.

Recent investigations have shown that an iron oxidation / reduction process can improve the quality of the coated steels by decreasing the amount of external selective oxidation. This economical process can be made during heating by modifying the air/gas ratio of the direct fire furnace or in the rapid cooling section by air injection. A sensor allows measuring continuously the iron oxide thickness of the oxidized strip.

In an EPR study employing yeast copper(I) thionein, GSH and Cu-GSH it was shown that thiyl radicals could be successfully generated from the thiolate sulfur via oxidation by photochemically formed superoxide at 77 K. The g-value was 2.036. Essentially no EPR detectable copper(II) was monitored under the experimental conditions, indicating that the oxidation reduction process is restricted to the thiolate sulfur. The Cu(I)-thiolate chromophores remained fully intact as deduced from chiroptical and luminescence measurements. Thus, copper thionein is supposed to be actively involved in the scavenging of oxygen free radicals by a reversible thiolate oxidation reduction cycle. The coordinated Cu(I) seems to serve as a prominent candidate to stabilize the transiently formed thiyl radical.

By using an electrolytic salt solution of two anionic species differing by their ionic radius or their molecular size, it is possible to accurately control the concentration of anionic doping agent without modification of the electrolyte conductivity. The conducting polymer film is electrosynthesized on the electrode in a solution containing small ions. Once de-doped, the film keeps the memory of the size of the doping anion and can be only re-doped by comparable or smaller anions. After the synthesis, the film is transferred to another electrolyte containing heteropolyanions ensuring the conductivity and a variable concentration of small ions acting as dopants. Measurement of the electroactivity of the polyaniline film is made by linear sweep voltammetry in classical electrochemical conditions.

The present paper describes the alternating copolymerization of P-ethenyl-N-n-propylphosphonamidic acid ethyl ester (1) with cyclic phosphonites (2). The copolymerization took place without added catalyst to produce 1:1 alternating copolymer 3. During the copolymerization the oxidation-reduction reaction of monomers occurred. Monomer 1 behaved as an oxidant monomer (Mox) whereas 2 acted as a reductant monomer (Mred). The structure and composition of copolymers were determined by 1H and 31P NMR spectra as well as the hydrolysis experiments. The copolymerization is reasonably explained by a mechanism of propagation via zwitterion intermediates. The apparent monomer reactivity ratios determined in benzonitrile at 130°C were r1=0.00 and r2(six-membered)=0.34.

The reactions of N-(ferrocenylmethyl)-N-methylamine, C(5)H(5)FeC(5)H(4)CH(2)(Me)NH, with hexachlorocyclotriphosphazene, N(3)P(3)Cl(6), led to the formation of the N-(ferrocenylmethyl)-N-methylaminocyclotriphosphazene derivatives, N(3)(-)P(3)Cl(6-n)[N(Me)CH(2)C(5)H(4)FeC(5)H(5)](n) (n = 1-3). Only small amounts of higher degrees of substitution could be detected. In the case of the disubstituted products, the ratio of isomers was dependent on the polarity of the solvent. In nonpolar solvents the ratio was trans > geminal > cis while in acetonitrile only equal amounts of trans and cis isomers were observed. The reaction of N-(ferrocenylmethyl)-N-methylamine with (methacryloylbutenedioxy)pentachlorocyclotriphosphazene, N(3)P(3)Cl(5)O(CH(2))(4)OC(O)C(Me)=CH(2), gives the surprising geminal isomer 2,2-N(3)P(3)Cl(4)[O(CH(2))(4)OC(O)C(Me)=CH(2)]N(Me)CH(2)C(5)H(4)FeC(5)H(5) and the tris derivative 2,2',4-N(3)P(3)Cl(3)[O(CH(2))(4)OC(O)C(Me)=CH(2)][N(Me)CH(2)C(5)H(4)FeC(5)H(5)](2). All of the phosphazene derivatives were characterized by elemental analyses, mass spectrometry, IR and NMR ((1)H, (13)C, (31)P) spectroscopy, and electrochemical techniques (cyclic, normal pulse, and differential pulse voltametry). The compounds all undergo a single, reversible oxidation reduction process.

The purpose of this paper is intended to study the effect of a magnetic field on electrochemical reactions without the MHD effect. We observed the effect of a magnetic field on the wavelengths (λ max ) of UV-VIS spectra for maximum absorption and the cyclic voltammograms of polypyrrole and poly( o -phenylenediamine) films prepared electrochemistry in a magnetic field. λ max of the polypyrrole films prepared at 6T shifted to longer wavelength, while we could not observed the effect of a magnetic field on λ max of poly( o -phenylenediamine) films. The peaks of redox potential at the curves of cyclic voltammogram for polypyrrole films shifted to lower potential.

NO2-による食肉の詳細な発色機構を明確にするため, ホルスタイン種去勢牛の大腿筋の組織内ヘムタンパク質の酸化および還元の各過程を種々の条件で分光学的に測定し, 解析した。酸化反応過程については, NO2-によるHbO2の酸化反応と比較した。また, 筋組織内メト型ヘムの還元後の分光学的特性をしらべた。1) 大腿筋の組織内ヘムタンパク質は, ポリアクリルアミドゲル・ディスク電気泳動の分析から, Mbが約75%, Hbが約20%, 残りの約5%がその他のヘムタンパク質であった。2) NO2-による筋組織内ヘムとHbO2の酸化反応過程は, おのおのみかけの一次反応とS字形で進行した。したがって, 両反応系には著明な差が認められる。HbO2の酸化反応は, H2O2添加で促進, カタラーゼ添加で遅延した。しかし, 筋組織内ヘムの酸化反応は, H2O2やカタラーゼの添加による影響が認められなかった。一方, 両反応系ともにSOD添加による影響がみられなかった。これらの反応性の差異に対する理由を考察した。3) 筋組織内メト型ヘムの還元速度は, pH 6.0とpH 7.4ともにNO2-濃度の低いほうがはやかった。同一のNO2-濃度では, その速度はpH 7.4のほうがpH 6.0に比べて約20%大きかった。[NO2-] / [heme] =1～2では, pH 7.4のほうがpH 6.0より約10時間はやく還元された。[NO2-] / [heme] =1 (pH 7.4, 5℃) のとき, 筋組織メト型ヘムがほぼ完全に還元されるまでに約16日を必要とした。[NO2-] / [heme] =10では, まったく還元されなかった。還元後の筋組織内ヘムは, 544nmと577nmに吸収極大があった。これは, 2価鉄ヘム (Fe2+) にNOが配位したNO型ヘムの誘導体と類似していた。

Well-dispersed supported V-P-O (Vanadium Phosphorus Oxyde) catalysts were prepared and tested in the selective oxidation of n-butane to maleic anhydride. Because of their high activity, it was possible to test titania-supported catalysts in a two-step oxidation reduction process at low temperatures. After n-butane adsorption and activation in the absence of molecular oxygen, desorption took place after subsequent introduction of molecular oxygen into the gas stream, leading to the selective formation of maleic anhydride. In-situ XANES spectroscopy was performed under reaction conditions in the two-step oxidation reduction process with a special titania-supported V-P-O catalyst with a high loading. The results of these experiments showed that, after equilibration, no more changes in the valence state of vanadium were observed after reduction or subsequent re-oxidation. This indicates that the generally assumed Mars-Van-Krevelen mechanism is not operative for the titania-supported V-P-O catalyst.