Cross-linked polyvinyl amidoxime fiber: a highly selective and recyclable adsorbent of gallium from Bayer liquor

Gallium, a scarce metal produced mainly from Bayer liquor, is widely used in semiconductors. Ion-exchange method is currently considered as the most effective method to recover gallium from Bayer liquor. In this article, fibrous amidoxime adsorbents are introduced to recover gallium from Bayer liquor. In addition, hydrazine cross-linked polyvinyl amidoxime (HPAO) fibers have been prepared. The structure of the as-prepared fibers was ascertained by FTIR, elemental analysis and weight gain rate. The adsorption kinetics, adsorption isotherm and recycling performance were investigated by batch method. Cross-linking duration was studied and it turned out to be an important factor to optimize the adsorption capacity and recycling performance. After 1.5 h cross-linking time, the fiber showed the highest gallium adsorption capacity of 14.83 mg/g in Bayer liquor. After 3 h cross-linking time, the fiber showed the best recycling performance, which retained 82.9% of the initial adsorption ability after four cycles. Adsorption capacity of vanadium was lower than 1 mg/g for all samples. HPAO displayed very fast adsorption kinetics with an equilibrium at 60 min. The EDS results confirmed the low extraction of aluminum and vanadium provided by HPAO fibers. The gallium-loaded fiber could be effectively eluted by acidified thiourea. With proper control of the cross-linking duration by hydrazine, HPAO fiber with high selectivity towards gallium, high adsorption capacity and good recycle performance could be obtained, which is promising for recovering gallium needed for industrial applications.     

自动化立体仓库消防给水设施设计探讨

立体仓库采用智能化出入库管理,集自动入库、智能化储存和自动化出库于一体,物品高度集中,火灾负荷集中的建筑。立体仓库的消防给水设施是其中重要的消防设施之一,本文主要分析立体仓库消防水系统的设计及参数的选择。     

Modification of pool boiling regimes by sand deposition

Sand spots, attached to a copper ball surface by means of polyvinyl acetate adhesive and distributed over the surface with areal density that ranges between one spot per 1.18 cm² (for low‐density spots) and one spot per 0.51 cm² (for high‐density spots), serve as a temporary heat transfer enhancer during the quenching in liquid nitrogen. Highest heat flux densities, achieved during quenching, lie in the range 10.8 to 20.2 W/cm², depending on the sand layer structure. Application of the temporary enhancer increases an amount of heat, evacuated by highly effective nucleate and transition boiling, by factor of 4.5 as compared with the bare sample. The process of sand layer preparation, data acquisition peculiarities, relationship between heat exchange efficiency and the spots areal density, along with sand grit size are discussed in this paper.     

Understanding the metabolic burden of recombinant antibody production in Saccharomyces cerevisiae using a quantitative metabolomics approach

The cellular changes induced by heterologous protein expression in the yeast Saccharomyces cerevisiae have been analysed on many levels and found to be significant. However, even though high‐level protein production poses a metabolic burden, evaluation of the expression host at the level of the metabolome has often been neglected. We present a comparison of metabolite profiles of a wild‐type strain with those of three strains producing recombinant antibody variants of increasing size and complexity: an scFv fragment, an scFv–Fc fusion protein and a full‐length IgG molecule. Under producing conditions, all three recombinant strains showed a clear decrease in growth rate compared with the wild‐type strain and the severity of the growth phenotype increased with size of the protein. The levels of 76 intracellular metabolites were determined using a targeted (semi) quantitative mass spectrometry based approach. Based on unsupervised and supervised multivariate analysis of metabolite profiles, together with pathway activity profiling, the recombinant strains were found to be significantly different from each other and from the wild‐type strain. We observed the most prominent changes in metabolite levels for metabolites involved in amino acid and redox metabolism. Induction of the unfolded protein response was detected in all producing strains and is considered to be a contributing factor to the overall metabolic burden on the cells.     

Optical Control of Cellular ATP Levels with a Photocaged Adenylate Kinase

We have developed a new tool for the optical control of cellular ATP concentrations with a photocaged adenylate kinase (Adk). The photocaged Adk is generated by substituting a catalytically essential lysine with a hydroxycoumarin-protected lysine through site-specific unnatural amino acid mutagenesis in both E. coli and mammalian cells. Caging of the critical lysine residue offers complete suppression of Adk's phosphotransferase activity and rapid restoration of its function both in vitro and in vivo upon optical stimulation. Light-activated Adk renders faster rescue of cell growth than chemically inducible expression of wild-type Adk in E. coli as well as rapid ATP depletion in mammalian cells. Thus, caging Adk provides a new tool for direct conditional perturbation of cellular ATP concentrations thereby enabling the investigation of ATP-coupled physiological events in temporally dynamic contexts.     

Rapid Discovery of Aspartyl Protease Inhibitors Using an Anchoring Approach

Pharmacophore searches that include anchors, fragments contributing above average to receptor binding, combined with one-step syntheses are a powerful approach for the fast discovery of novel bioactive molecules. Here, we are presenting a pipeline for the rapid and efficient discovery of aspartyl protease inhibitors. First, we hypothesized that hydrazine could be a multi-valent warhead to interact with the active site Asp carboxylic acids. We incorporated the hydrazine anchor in a multicomponent reaction and created a large virtual library of hydrazine derivatives synthetically accessible in one-step. Next, we performed anchor-based pharmacophore screening of the libraries and resynthesized top-ranked compounds. The inhibitory potency of the molecules was finally assessed by an enzyme activity assay and the binding mode confirmed by several soaked crystal structures supporting the validity of the hypothesis and approach. The herein reported pipeline of tools will be of general value for the rapid generation of receptor binders beyond Asp proteases.     

炭黑N660/裂解炭黑并用在轮胎气密层胶中的应用研究

研究炭黑N660/裂解炭黑并用对溴化丁基橡胶(BIIR)气密层胶性能的影响。结果表明:裂解炭黑粒径大于炭黑N660;随着裂解炭黑用量的增大,胶料的门尼粘度提高,t10和t90总体延长,加工安全性能较好,硫化速度较慢;与纯炭黑N660胶料相比,添加裂解炭黑的胶料物理性能总体降低,炭黑N660/裂解炭黑并用比为40/20的胶料综合物理性能较好,成本降低;炭黑N660/裂解炭黑并用胶料的耐热氧老化性能和气密性较好。