Enzymatic synthesis of optically active ferrocenes by immobilized lipase from Candida Antarctica

Immobilized lipase (Candida Antarctica lipase, CAL) efficiently catalyzes the transesterification and amidation of the racemic ferrocenes, 1‐hydroxyethylferrocene, (±)‐ 1 , 1‐hydroxy[3](1,1′) ferrocenophane, (±)‐ 4 , 1‐amonoethylferrocene, (±)‐ 2 , and 1‐amono[3](1,1′) ferrocenophane, (±)‐ 5 , with acyl esters, resulting in the formation of R products possessing high enantiomeric purity. When 1‐hydroxyethylferrocene, (±)‐ 1 , and 1‐hydroxy[3](1,1′) ferrocenophane, (±)‐ 4 , was used as substrate diisopropyl ether was a suitable solvent. In the reaction conditions investigated, the use of vinyl acetate in diisopropyl ether gave the best yield of (R)‐ 1a (49%, 99% ee) after 2 h of incubation at 30 °C. But, with the amino ferrocenes, 1‐amonoethylferrocene, (±)‐ 2 , and 1‐amono[3](1,1′) ferrocenophane, (±)‐ 5 , as substrate, diisopropyl ether was unsuitable as a solvent owing to the low solubility of the substrate in this solvent. Using tetrahydrofuran as a solvent, enzymatic amidation of 1‐amonoethylferrocene, (±)‐ 2 , gave the best yield of (R)‐ 2a (21%, 99% ee) after 120 h of incubation at 30 °C. CAL working in organic solvent is able to efficiently carry out the resolution of ferrocenyl alcohol and amine derivatives which have similar structures, such as (±)‐ 1 and (±)‐ 2 , (±)‐ 4 and (±)‐ 5 which possess central chirality. This enzyme accepted only non‐bulky primary alcohols and amines as ferrocenyl substrates. © 1999 Society of Chemical Industry     

Detection of a new crosslinking and properties of liquid polysulfide polymer

Polysulfide polymer was found in the 19th century. At present, this polymer consists of the repetition of disulfide linkage and diethyl formal and has SH terminals. This liquid polymer (LP) is cured by lead dioxide. We studied polysulfide polymerization and elastomeric mechanical properties of cured LP. The condition of polymerization greatly influenced its elastomeric mechanical properties. These phenomena could not be explained from the point of residual unreacted chlorine or produced OH terminals. We found that additional crosslinking sites are produced during polymerization besides crosslinking agents trichloropropane (TCP) by using the Insensitive Nuclei Enhanced by Polarization Transfer (INEPT) method. We proposed their chemical structures and reaction scheme of their formation. TCP and also these additional crosslinking sites influence the modulus of cured LP. The sum of the intensity of their crosslinking sites by ¹³C‐NMR had good correlation with 300% modulus of cured LP. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 59–66, 1999     

Synthesis of branched poly(lactide) using polyglycidol and thermal, mechanical properties of its solution-cast film

Branched poly(lactide)(PLA)s with various lengths of graft chain were synthesized by ring-opening polymerization of l- or d-lactide (l- or d-LA) in bulk using polyglycidol as a macroinitiator. The properties of polymer films of branched PLLA or PDLA obtained and their stereocomplex were investigated through thermal analysis and tensile testing. The branched PLLA or PDLA film exhibited a lower glass transition temperature (T_g), melting temperature (T_m), crystallinity, Young's modulus and a higher strain at break than the corresponding linear PLLA or PDLA film. The branched PLLA/branched PDLA stereocomplex film showed a high maximum stress and a high Young's modulus keeping its high strain at break. Moreover, the usefulness of branched PLLA or PDLA as a plasticizer of linear PLLA was investigated with 1:9 blend or stereocomplex film prepared from the branched PLLA or branched PDLA and linear PLLA. The blend or linear PLLA/branched PDLA stereocomplex film showed a higher strain at break compared with linear PLLA film. The mechanical properties of the blend or linear PLLA/branched PDLA stereocomplex film could easily be controlled by changing the molecular weight of branched PLA.     

Distribution Behavior of Neptunium by Extraction with N,N-dialkylamides (DEHDMPA and DEHBA) in Mixer-Settler Extractors

The extraction properties of N,N-di(2-ethylhexyl)-2,2-dimethylpropanamide (DEHDMPA) and N,N-di(2-ethylhexyl)butanamide (DEHBA) for Np(V) and Np(VI) were studied by a batch method using various nitrate ion concentrations. The distribution ratios of Np(VI) obtained with DEHDMPA and DEHBA exceeded unity when the nitrate ion concentration was > 3 mol/dm³, while DEHDMPA and DEHBA barely extracted Np(V). A continuous counter-current experiment using mixer-settler extractors was performed to evaluate the behavior of Np in a process comprising two cycles using DEHDMPA and DEHBA as extractants. The feed was nitric acid containing U, Pu, Np, and several fission products. The results indicated that part of Np(V) changed its valence state to Np(IV) or Np(VI) after the 1st experimental cycle. The recoveries of Np in the streams of U fraction and U-Pu fraction were 63.7% and 29.1%, respectively.     

Selective Catalytic Reduction of NO by C3H6 over Co/Al2O3 Catalyst with Extremely Low Cobalt Loading

In order to reveal the optimum Co loading, the selective catalytic reduction of NO with C₃H₆ over Co/Al₂O₃ catalyst was studied in a systematic fashion by varying the amount of cobalt oxide. It was found that upon loading a small amount of cobalt oxide (namely 0.5 wt% on a Co metal basis), the combination between Co(II) acetate salt and a high-purity alumina provided an active catalyst in the presence of excess oxygen and water. TPR measurement showed the presence of Co species other than CoAl₂O₄ spinel in the most excellent performance catalyst, from which the active sites should be produced.     

Critical update on 2‐methacryloyloxyethyl phosphorylcholine (MPC) polymer science

2‐Methacryloyloxyethyl phosphorylcholine (MPC) is a custom methacrylate with a zwitterionic phosphorylcholine moiety on the side chain. In the past 25 years, MPC has been used as a building block for a wide range of polymeric biomaterials because of its excellent resistance to nonspecific protein adsorption, cell adhesion, and blood coagulation. Recently, MPC polymers with specific features have been used in bioengineering and nanomedicine. This review focuses on three topics that highlight the latest findings on MPC polymers, that is, specific recognition of C‐reactive protein (CRP), cell‐membrane‐penetration abilities, and lubrication properties. These developments will extend the applications of this biomimetic material from bioinert polymers to biosensing, CRP inhibitors, prodrug carriers, subcellular bioimaging, cell manipulation, and joint replacement. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41766.     

炉料弹性模量对高炉内炉料运动行为与应力分布的影响

采用三维离散元法对不同弹性模量条件下,5000m3高炉内的炉料的运动行为进行了研究.发现,当弹性模量取0.06GPa时,炉料颗粒的变形量超过了自身半径的1/2,炉身处发生严重的混料现象,炉缸内焦炭颗粒发生堆积,无焦空间减小,而且计算在100步以后自动终止.而当弹性模量在10～0.6GPa范围内变化时,炉身段料层倾角随弹...     

Automatic detection method of cracks from concrete surface imagery using two‐step light gradient boosting machine

Automated crack detection based on image processing is widely used when inspecting concrete structures. The existing methods for crack detection are not yet accurate enough due to the difficulty and complexity of the problem; thus, more accurate and practical methods should be developed. This paper proposes an automated crack detection method based on image processing using the light gradient boosting machine (LightGBM), one of the supervised machine learning methods. In supervised machine learning, appropriate features should be identified to obtain accurate results. In crack detection, the pixel values of the target pixels and geometric features of the cracks that occur when they are connected linearly should be considered. This paper proposes a methodology for generating features based on pixel values and geometric shapes in two stages. The accuracy of the proposed methodology is investigated using photos of concrete structures with adverse conditions, such as shadows and dirt. The proposed methodology achieves an accuracy of 99.7%, sensitivity of 75.71%, specificity of 99.9%, precision of 68.2%, and an F‐measure of 0.6952. The experimental results demonstrate that the proposed method can detect cracks with higher performance than the pix2pix‐based approach. Furthermore, the training time is 7.7 times shorter than that of the XGBoost and 2.3 times shorter than that of the pix2pix. The experimental results demonstrate that the proposed method can detect cracks with high accuracy.