Fast Li Storage in MoS2‐Graphene‐Carbon Nanotube Nanocomposites: Advantageous Functional Integration of 0D, 1D,and 2D Nanostructures

A 3D porous composite consisting of nano‐0D MoS₂, nano‐1D carbon nanotubes (CNTs), and nano‐2D graphene is successful prepared using an electrostatic spray deposition (ESD) technique. Depending on the preparation procedure either nanodots of amorphous MoS₂ (0.5–5 nm) or nanocrystalline few‐layered MoS₂ (5–10 nm) bonded to graphene‐carbon nanotubes backbone are obtained. These functionalized carbon nanotubes adhere to a porous graphene‐based network. Such composites can be directly ­deposited on the current collectors without any binder or conductive additives to assemble a battery that shows superior rate performance and cycling ­stability. For nanodots, nucleation and diffusion issues usually connected with ­conversion are largely mitigated if not totally nullified. The use of mechanically and diffusionally isolated but electrochemically well connected electroactive nanodots offer an effective solution to render conversion reaction reversible. The use of nano‐1D and nano‐2D carbon structures offer additional electrical and mechanical advantages that are discussed. Furthermore, this technique, which is easily extendable to other electrode materials, seems to be of a great potential, especially for thin‐film batteries, flexible batteries, and future ­paintable batteries.     

Superior Lithium Storage Properties of β‐FeOOH

Several crystal forms of FeOOH are recently reported to be highly promising for lithium storage due to their high capacity, low cost, and environmental friendliness. In particular, β‐FeOOH has shown a capacity of ≈1000 mAh g^?1, which is comparable to other promising iron‐based anodes, such as Fe₂O₃ and Fe₃O_4. However, its storage mechanisms are unclear and the potential for further improvement remains unexplored. Here, it is shown that this material can have a very high reversible capacity of ≈1400 mAh g^?1, which is 20%–40% higher than Fe₂O₃ and Fe₃O₄. Such a high capacity is delivered from a series of reactions including intercalation and conversion reactions, formation/deformation of solid‐state electrolyte interface layers and interfacial storage. The mechanisms are studied by a combination of electrochemical and X‐ray absorption near edge spectroscopic approaches. Moreover, very long cycling performance, that is, after even more than 3000 cycles the material still has a significant capacity of more than 800 mAh g^?1, is obtained by a simple electrode design involving introducing a rigid support into porous electrodes. Such long cycling performance is for the first time achieved for high‐capacity materials based on conversion reactions.     

Where bio meets nano: the many uses for nanoporous aluminum oxide in biotechnology

Porous aluminum oxide (PAO) is a ceramic formed by an anodization process of pure aluminum that enables the controllable assembly of exceptionally dense and regular nanopores in a planar membrane. As a consequence, PAO has a high porosity, nanopores with high aspect ratio, biocompatibility and the potential for high sensitivity imaging and diverse surface modifications. These properties have made this unusual material attractive to a disparate set of applications. This review examines how the structure and properties of PAO connect with its present and potential uses within research and biotechnology. The role of PAO is covered in areas including microbiology, mammalian cell culture, sensitive detection methods, microarrays and other molecular assays, and in creating new nanostructures with further uses within biology.     

Adsorption into the MFI zeolite of aromatic molecule of biological relevance. Investigations by Monte Carlo simulations

Adsorption of paracresol and water into the silicalite-1 (MFI) zeolite has been investigated using canonical and grand-canonical Monte Carlo simulations. The most stable sites of adsorption of paracresol are found to be located at the channel intersections. Grand-canonical simulations have shown that at low loading, water molecules adsorb preferably at the vicinity of paracresol molecules, whereas they are also located in the sinusoidal channels as the loading increases. In order to explain the experimental adsorption isotherm observed for the coadsorption of water and paracresol in the MFI zeolite we propose a new concept of apparent adsorption enthalpy that varies with the concentration of the solution. The mathematical expression for the apparent enthalpy is introduced in an adsorption isotherm model. We shall refer to this theoretical isotherm as a non-langmuirian isotherm. The non-linear expression for the apparent adsorption enthalpy accounts for a variable accessibility of the sites of adsorption with respect to the concentration of the solution. Figure Co-adsorption of paracresol and water in silicalite-1 zeolite and comparison between experimental and modelled adsorption isotherms.     

基于纳米多孔硅Bragg反射镜免标记生物传感器的研究

构建一种基于多孔硅Bragg反光镜的免标记的纳米生物传感器,通过在纳米多孔硅上固定的适配子的特异性识别能力,检测溶液中四环素浓度。当适配子结合不同浓度的四环素溶液时,引起多孔硅Bragg反光镜内部有效折射率的变化,反射谱峰位进而发生变化。传感器的有效检测范围为1~200μg/L,检测限为1μg/L。     

MC3T3-E1 osteoblast attachment and proliferation on porous hydroxyapatite scaffolds fabricated with nanophase powder

Porous bone tissue engineering scaffolds were fabricated using both nano hydroxyapatite (nano HA) powder (20 nm average particle size) and micro HA powder (10 microm average particle size), resulting in sintered scaffolds of 59 vol% porosity and 8.6 +/- 1.9 microm average grain size and 72 vol% porosity and 588 +/- 55nm average grain size, respectively. Scanning electron microscopy was used to measure both the grain size and pore size. MC3T3-E1 osteoblast (OB) attachment and proliferation on both nano HA and micro HA porous scaffolds were quantified. As expected, OB cell number was greater on nano HA scaffolds compared with similarly processed micro HA scaffolds 5 days after seeding, while OB attachment did not appear greater on the nano HA scaffolds (p < 0.05).     

Partitioning of pyrene-labeled phospho- and sphingolipids between ordered and disordered bilayer domains

Here we have studied how the length of the pyrene-labeled acyl chain (n) of a phosphatidylcholine, sphingomyelin, or galactosylceramide affects the partitioning of these lipids between 1), gel and fluid domains coexisting in bovine brain sphingomyelin (BB-SM) or BB-SM/spin-labeled phosphatidylcholine (PC) bilayers or 2), between liquid-disordered and liquid-ordered domains in BB-SM/spin-labeled PC/cholesterol bilayers. The partitioning behavior was deduced either from modeling of pyrene excimer/monomer ratio versus temperature plots, or from quenching of the pyrene monomer fluorescence by spin-labeled PC. New methods were developed to model excimer formation and pyrene lipid quenching in segregated bilayers. The main result is that partition to either gel or liquid-ordered domains increased significantly with increasing length of the labeled acyl chain, probably because the pyrene moiety attached to a long chain perturbs these ordered domains less. Differences in partitioning were also observed between phosphatidylcholine, sphingomyelin, and galactosylceramide, thus indicating that the lipid backbone and headgroup-specific properties are not severely masked by the pyrene moiety. We conclude that pyrene-labeled lipids could be valuable tools when monitoring domain formation in model and biological membranes as well as when assessing the role of membrane domains in lipid trafficking and sorting.     

Predicting Biogeochemical Calcium Precipitation in Landfill Leachate Collection Systems

Clogging of leachate collection systems within municipal solid waste landfills can result in greater potential for contaminants to breach the landfill barrier system. The primary cause of clogging is calcium carbonate (CaCO_3(s)) precipitation from leachate and its accumulation within the pore space of the drainage medium. CaCO_3(s) precipitation is caused by the anaerobic fermentation of volatile fatty acids (VFAs), which adds carbonate to and raises the pH of the leachate. An important relationship in modeling clogging in leachate collections systems is a yield coefficient that relates microbial fermentation of VFAs to precipitation of calcium carbonate. This paper develops a new, mechanistically based yield coefficient, called the carbonic acid yield coefficient (Y_H), which relates the carbonic acid (H₂CO₃) produced from microbial fermentation of acetate, propionate, and butyrate to calcium precipitation. The empirical values of Y_H were computed from the changes in acetate, propionate, butyrate, and calcium concentrations in leachate as it permeated through gravel-size material. The theoretical and empirical results show that the primary driver of CaCO_3(s) precipitation is acetate fermentation. Additionally, other non-calcium cations (e.g., iron and magnesium) precipitated with carbonate (CO_2-) when present in the leachate. A common yield between total cations bound to CO₃ ^2- and H₂CO₃ produced, called the calcium carbonate yield coefficient (Y_c), can reconcile the empirical yield coefficient for synthetic and actual leachates.     

“增温溶解,保温过柱,温水解吸“提制二氢杨梅素(一)

采用“增温溶解 ,保温过柱 ,温水解吸”的方法对显齿蛇葡萄中的二氢杨梅素进行提制研究。结果表明 :该方法的适宜温度为 5 0～ 70℃ ,最好为 6 0℃ ,方法能很好地将 70 %左右的二氢杨梅素提纯到80 % ;提纯二氢杨梅素时 ,单位数量的D 16大孔吸附树脂处理料液的数量 ,主要取决于料液中二氢杨梅素的纯度。     

Glycolipid membrane anchored recombinant protein production from CHO cells cultGred on porous microcarriers

Recombinant proteins were harvested from Chinese hamster ovary (CHO) cells by a controlled release process, which increased the purity and concentration of the harvested protein. Recombinant human melano-transferrin (p97) was expressed linked to the outer surface of CHO cells by a glycosyl-phosphatidylinositol (GPI) membrane anchor. Cells were grown to confluence in T-flask culture, and the p97 harvested by replacing the growth medium for 30 min with phosphate-buffered saline (PBS) containing 10 mU/mL phosphatidylinositol-phospholipase C (PI-PLC). The GPI anchor was selectively cleaved by PI-PLC. In fresh medium, the CHO cells regained over 95% of their p97 expression within 40 h. The process was repeated for eight harvests. Harvested protein concentrations varied from 1.5 to 3.8 mug/mL due to difficulties in maintaining stable confluent T-flask cultures. Harvesting from cells growing on porous microcarriers was investigated to increase p97 product concentrations and to overcome culture stability problems. Semicontinuous cultures were maintained in spinners for up to 76 days with average bioreactor cell densities of over 10(7) cell/mL. The p97 was harvested at up to 100 mug/mL and 30% purity with protein production remaining stable for 4 harvest cycles. Production of high levels of p97 from CHO cells was maintained at 0.5% serum. (c) 1994 John Wiley & Sons, Inc.