Decontamination of mobile phones and electronic devices for health care professionals using a chlorhexidine/carbomer 940■gel

Though they reduce microorganism growth, current hospital disinfectants also damage many of today’s modern electronic devices such as tablets and smartphones. Herein, the efficacy of a new chlorhexidine digluconate gel (CDG) was tested as a disinfectant for mobile and electronic devices in a clinical environment. Specifically, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and methicillin resistant Staphylococcus aureus were used to infect the screen of eight smartphones. The CDG was prepared at concentrations of 2%, 4% and 6%, and tested on paper disks infected with these bacteria before being tested on the smartphones. The devices were disinfected with the CDG gel (4%) at two times: immediately and after 5 min of the bacterial contamination. In all cases, the CDG gel eliminated 100% of gram-positive and gram-negative microorganisms compared to the control (without any agent). In addition, the gel did not damage the smartphones. Therefore, our study suggests that the CDG gel may be applied to disinfect a wide range of electronic devices for health care professionals in the hospital environment.     

Antioxidant activity of flavonol aglycones and their glycosides in methyl linoleate

The antioxidant activities of the flavonol aglycones, quercetin and myricetin, and their selected glycosides were compared in bulk methyl linoleate oxidized at 40°C. Methyl linoleate hydroperoxide formation, hydroperoxide isomer distribution, and ketodiene formation were followed by using high-performance liquid chromatography (HPLC) analysis. The aglycones, quercetin and myricetin, were consistently more active in bulk methyl linoleate than their glycosides and more active than α-tocopherol at 500 and 1000 μM. At 50 μM, the order of activity was myricetin > α-tocopherol > quercetin, and the order of activity of quercetin and its derivatives was quercetin > quercitrin > isoquercitrin > rutin. Myricitrin was slightly less active than myricetin. The sugar moiety was shown to have a marked effect on the antioxidant activity of flavonols. The rhamnoside derivatives, quercitrin and myricitrin, both possessed activity close to that of their corresponding aglycones. The different activities of glycosides could be partly explained by different solubilities and by differences in oxidizability of glycosides containing a monosaccharide or disaccharide at the C₃ position. The effect on hydroperoxide isomer distribution indicates that α-tocopherol was a more effective hydrogen donor than flavonoids, although flavonoids were more effective in inhibiting oxidation of methyl linoleate.     

预分散溶剂萃取分离苯酚溶液的研究

Predispersed solvent extraction (PDSE) is a new method for separating solutes from aqueous solution by solvent extraction and one which has shown promise for extraction from extremely dilute solution very efficient and very quick. The use of colloidal liquid aphrons in predispersed solvent extraction may ameliorate the problems such as emulsion formation, reduction of interracial mass transfer and low interfacial mass transfer areas in solvent extraction process. In present paper, colloidal liquid aphrons are successfully generated using kerosene as a solvent,tributyl phosphate(TBP) as an extractant, sodium dodecyl benzene sulphate(SDBS) as surfactant in aqueous phase and Tween-80 in oil phase. Extraction of phenol from dilute solution was studied by using colloidal liquid aphrons and colloidal gas aphrons in a semi-batch extraction column. It has been found that the PDSE process is more suitable for extraction of dilute solutions. It has also been discovered that the PDSE process has a great advantage over traditional single-stage extraction process.     

高硅含量有机无机杂化乳液的制备和溶胶-凝胶驱使成膜

A novel polymer/SiO2 hybrid emulsion (PAES) was prepared by directly mixing colloidal silica with polyacrylate emulsion (PAE) modified by a saline coupling agent. The sol-gel-derived thin films were obtained by addition of co-solvents into the PAES. The effects of γ-methacryloxypropyltrimethoxysilane (KH-570) content and co-solvent on the properties of PAES films were investigated. Dynamic laser scattering (DLS) data indicate that the average diameter of PAES (96 nm) is slightly larger than that of PAE (89 nm). Transmission electron microscopy (TEM) photo discloses that colloidal silica particles are dispersed uniformly around polyacrylate particles and some of the colloidal silica particles are adsorbed on the surface of PAE particles. The crosslinking degree data and Fourier transform infrared (FT-IR) spectra confirm that the chemical structure of the PAES is changed to form Si-O-Si-polymer crosslinking networks during the film formation. Atomic force microscope (AFM) photos show the solvent induced sol-gel process of colloidal silica and the Si-based polymer distribution on the film surface of the dried PAES. Thermogravimetric analysis (TGA) curves demonstrate that the PAES films display much better thermal stability than PAE.     

低温水相一步合成钛酸钡：颗粒合成研究

The formation of BaTiO3 nanoparticles via the reaction of BaCl2, TiCl4 and NaOH in aqueous solution has been systematically studied. The formation of BaTiO3 from the ionic precursors has been elucidated to be a very rapid process, occurring at temperature higher than 60℃. Furthermore, the particle size could be controlled by the proper selection of the synthesis conditions （e.g. reactant concentration of 0.5-1.0mol.L^-1, temperature of 80- 95℃ and pH ≥ 13）. A two-step precipitation mechanism was proposed. The first stage of the synthesis involved the formation of amorphous Ti-rich gel phase. The second stage of the synthesis was the reaction between the amorphous phase and the solution-based Ba^2＋ ions, which led to the crystallization of BaTiO3. Based on the particle formation mechanism, a novel method, high gravity reactive precipitation, was proposed and used to mass production of BaTiO3 of average particle size of about 60 nm and with narrow particle size distribution. Because it could break up the amorphous Ti-rich gel into small pieces, intensify mass transfer, promote the reaction rate of amorphous Ti-rich gel with Ba^2＋ ions.     

MOLECULAR DYNAMICS SIMULATIONS OF FILLED AND EMPTY CAGE-LIKE WATER CLUSTERS IN LIQUID WATER AND THEIR SIGNIFICANCE TO GAS HYDRATE FORMATION MECHANISMS

Molecular dynamics simulations are performed to observe the evolutions of 5~(12) and 5~(12)6~2 cage-like water clusters filled with or without a methane molecule immersed in bulk liquid water at 250 K and 230 K. The lifetimes of these clusters are calculated according to their Lindemann index δ (t) using the criteria of δ≥0.07. For both the filled and empty clusters, we find the dynamics of bulk water determines the lifetimes of cage-like water clusters, and that the lifetime of 5~(12) 6~2 cage-like cluster is the same as that of 5~(12) cage-like cluster. Although the methane molecule indeed makes the filled cage-like cluster more stable than the empty one, the empty cage-like cluster still has chance to be long-lived compared with the filled clusters. These observations support the labile cluster hypothesis on the formation mechanisms of gas hydrates.     

Investigation on characteristics of liquid self-diffusion in slit nanopores using simple quasicrystal model of liquid☆

Dynamical properties of liquid in nano-channels attractmuch interest because of their applications in engineering and biological systems. The transfer behavior of liquid confined within nanopores differs significantly from that in the bulk. Based on the simple quasicrystal model of liquid, analytical expressions of self-diffusion coefficient both in bulk and in slit nanopore are derived from the Stokes–Einstein equation and the modified Eyring's equation for viscosity. The local self-diffusion coefficient in different layers of liquid and the global self-diffusion coefficient in the slit nanopore are deduced fromthese expressions. The influences of confinement by porewalls, pore widths, liquid density, and temperature on the self-diffusion coefficient are investigated. The results indicate that the self-diffusion coefficient in nanopore increaseswith the porewidth and approaches the bulk value as the pore width is sufficiently large. Similar to that in bulk state, the self-diffusion coefficient in nanopore decreases with the increase of density and the decrease of temperature, but these dependences are weaker than that in bulk state and become evenweaker as the porewidth decreases. Thiswork provides a simplemethod to capture the physical behavior and to investigate the dynamic properties of liquid in nanopores.     

A Population Balance Model for Disperse Systems： Particle Size Distribution in Suspension Polymerization

On the basis of population balance a mathematical model is developed to describe the formation of polymer partlcle in styrene suspension polymerization. The characteristics of coalescence and breakage of droplets and the gel effect are analyzed in particular. Parameters of the models are esthnztted by experimental. on reaction conversion and particle size distributlon. The results show that the model is suitable for predicting polymerization processes.     

Performance of EDAB-HCl acid blended system as fracturing fluids in oil fields简

Due to the high price and formation damage of the guargum fracturing fluid, many oilfields are more and more interested in surfactant based fracturing fluids. The rheological properties of erucicamide dimethyl amidopropyl betaine （EDAB）-HC1 acid blended system and its suitability as fracturing fluid were investigated in this work. The effects of pH, concentration of EDAB, and temperature on the rheological properties of the blended system were studied. The results show that addition of EDAB improved the viscosity of the system from less than 10 mPa. s to about 400 mPa. s, which could retard the acid-rock reaction to about one half at 60℃ and one quarter at 90℃ comparing to straight HC1 acid, suggesting that there is sufficient time for the blended fluid to react with formation rock when it is used as fracturing fluid in an oil field. Core flow tests demonstrated that the EDAB-acid blended fluid could divert itself from high permeability formation core to low permeability one, thus ensuring proper acid placement in the target reservoirs.     

Effect of La_2O_3 Addition on Sintering Properties of Magnesia

Light burned magnesia powders with different particle sizes were obtained by calcining crystalline magnesite. Sintered magnesia was prepared from the light burned magnesia powders by adding different amounts of La_2O_3. The effect of the La_2O_3 addition on the densification of magnesia was studied. The results show that the densification of sintered magnesia can be promoted both by reducing the particle size of the light burned powder and by adding small amounts of La_2O_3. The effect of the La_2O_3 addition is more significant: the maximum bulk density of the sintered magnesia can reach 3.49 g · cm~(-3) and the apparent porosity can be reduced to 0.33%. During sintering, Ca~(2+) from the impurities enters La_2O_3 lattices, causing lattice distortion of La_2O_3 thus promoting the formation of La4.67(SiO_4)_3 O phase and CaLa_4(SiO_4)_3 O phase, which fill the pores between the MgO grains and promote the densification of sintered magnesia.     

Molecular weights of poly(butyl 2-cyanoacrylate) produced during nanoparticle formation

The molecular weights and distributions of poly(buty1 2-cyanoacrylate) produced during the formation of nanoparticles under a range of polymerisation conditions have been determined by gel permeation chromatography. The data indicate that the type of steric stabiliser and concentration of the monomer added to the polymerisation medium influences the resulting molecular weight of the polymer. In all systems the bulk of the polymer had a low molecular weight (<10000) but nanoparticles stabilised with dextrans or poloxamer 188 also yielded a high molecular weight component (>20000). The results are interpreted with regard to the possible effects on the degradation of nanoparticles and their drug release characteristics. Tentative proposals are made concerning the mechanisms of nanoparticle formation.     

铝离子-聚合物凝胶调驱体系配方室内优选研究

铝离子-聚合物凝胶调驱技术是一种较为成熟的CDG调驱技术。从开展的调驱试验看,均取得了较好的增油效果,在相同的条件下,注剂成本低于单纯的聚合物驱油。由于A区水源矿化度高、钙镁二价离子含量高,导致注入液粘度低,注入浓度1350mg.L-1左右时,注入液粘度才达到45mPa.s,而萨南外试验区注入水配制的1200mg.L-1的聚合物溶液粘度则可达到66.0mPa.s以上。为此开展了室内研究工作,研究不同浓度铝离子-聚合物凝胶与不同水质的配伍性,研究表明配制水的矿化度越高,越难形成铝离子-聚合物凝胶;聚合物的分子量增大、溶液浓度增加、聚铝比降低,体系的粘度和转变压力增大,铝离子-聚合物凝胶越易于形成。随着体系中聚合物浓度的增加,采收率提高幅度增大,考虑到经济效益等问题,研究认为中分聚合物清水体系450mg.L-1、聚铝比30∶1为铝离子-聚合物凝胶体系可选配方,该数据为开展现场试验提供了理论依据。     

Osteocompatibility characterization of polyacrylonitrile carbon nanofibers containing bioactive glass nanoparticles

A kind of composite carbon nanofibers (CNF) containing bioactive glass (BG) nanoparticles was produced for bone regeneration by a combination of electrospinning and sol–gel techniques. To produce the BG, compounds such as calcium nitrate, triethyl phosphate and tetraethyl orthosilicate were used as precursors and hydrolyzed to form a sol–gel solution, which was then added to a polyacrylonitrile (PAN) solution in N,N-dimethylformamide. The resulting mixture was electrospun to form PAN nanofibers containing the BG precursors. Upon oxidation and carbonization, the PAN nanofibers and BG precursors transformed into continuous CNF embedded with BG nanoparticles (CNF/BG). Through this fabrication technique, several CNF/BG composites were obtained by controlling the feeding ratios of the different precursors giving rise to BG nanoparticles with various compositions (i.e. containing 70–90 mol% of SiO₂ component). In vitro biomineralization in a simulated body fluid and co-culture with MC3T3-E1 osteoblasts studies were performed to evaluate the osteocompatibility of the CNF/BG nanoparticle composites. When compared to pure CNF, the CNF/BG composites showed an improved ability to promote the in vitro formation of apatite and MC3T3-E1 proliferation, which was found to be dependent upon the composition of BG nanoparticles.     

Bioactivity behaviour of biodegradable material comprising bioactive glass

Biocomposite of bioactive glass (BG) with chitosan polymer (CH) is prepared by freeze-drying technique. Obtained material is investigated by using several physico-chemical methods. The XRD and FTIR show the interface bonding interactions between glass and polymer. The specific surface and porosity of biocomposite were determined. In vitro assays were employed to evaluate the effect of chitosan addition on the glass by studying the chemical reactivity and bioactivity of the BG and BG/CH biocomposite after soaking in a simulated body fluid (SBF). The obtained results show the formation of a bioactive hydroxycarbonate apatite (HCA) layer and highlight the bioactivity and the kinetics of chemical reactivity of bioactive glass, particularly after association with chitosan. The BG/CH biocomposite has excellent ability to form an apatite layer. Inductively coupled plasma-optical emission spectrometry (ICP-OES) highlights the negative effect of chitosan on the silicon release toward the SBF of bioactive glass when in vitro assays.     

Facile production of porous bioactive glass scaffolds by the foam replica technique combined with sol–gel/electrophoretic deposition

3D porous bioactive glass (BG) scaffolds were fabricated by the foam replication technique combining sol–gel and electrophoretic deposition (EPD) processes. A special EPD set-up was built to optimize the scaffolds fabrication, which results in the rapid production of BG-based scaffolds in comparison to the traditional time-consuming foam replication technique normally used for the same kind of BG scaffolds. The influences of parameters related to the BG sol (aging time) as well as to the electrically driven process (deposition voltage) were studied and discussed in terms of the final scaffolds microstructure. Bioactivity of the samples, in terms of hydroxycarbonate apatite (HCA) formation in simulated body fluid (SBF), was determined after 1 day of immersion in SBF, confirming the suitability of the new scaffolds for bone regeneration applications.     

Enhancing In Vitro Bioactivity of Melt‐Derived 45S5 Bioglass® by Comminution in a Stirred Media Mill

45S5 Bioglass^® (45S5 BG) is a frequently applied Type A bioactive material, capable of forming an inherent bond to bone and soft tissue. Currently, applied melt‐derived bioactive glass powders (BG) exhibit particle sizes between a few to several hundred micrometers. Recent studies on nanometer‐sized bioactive glasses (nBGs), produced by bottom‐up methods like sol–gel processing or flame spray pyrolysis, have indicated their great potential for several biomedical applications. In this study, the feasibility of top‐down processing starting from bulk 45S5 BG by wet comminution in a stirred media mill was investigated. The products were assessed by in vitro hydroxycarbonate apatite (HCAp) formation in simulated body fluid, which is a marker for bioactive behavior. The study reveals the paramount influence of the used solvent for a successful top‐down processing: In comparison with the as‐received material bioactivity is lost for powders processed in water, preserved for comminution in ethanol and increased for powders processed using the alcohols n‐butanol, n‐pentanol, and n‐hexanol. It was also found that only for the latter solvents, the chemical composition of the glass is maintained during comminution. Flake‐like, slightly porous particles with specific surface areas of ~25–30 m²/g are obtained. Thus, the presented comminution approach offers a convenient technique to process 45S5 BG with enhanced bioactivity.     

聚合物凝胶堵漏剂的研究与应用进展

聚合物凝胶堵漏剂是近年来逐步完善和发展起来的一种堵漏材料。简要介绍了聚合物凝胶堵漏剂特点及作用机理,并对国内外聚合物凝胶堵漏剂的研究及应用进行了评述。聚合物凝胶堵漏剂包括地下交联聚合物凝胶和可吸水膨胀交联聚合物凝胶,交联聚合物凝胶强度较低,必须与其他刚性材料配合才能很好地发挥作用。在堵漏施工中,交联聚合物凝胶不受漏失通道的限制,能够通过挤压变形进入裂缝和孔洞空间,最终达到封堵漏层的目的。现场应用表明,聚合物凝胶堵漏剂与其他材料配合使用,能很好地解决钻井过程中的恶性漏失,堵漏成功率高,对碳酸盐岩、裂缝发育地层及孔洞漏失特别有效。     

改性聚丙烯酰胺凝胶堵水剂的研制

针对树脂类凝胶堵剂易受温度和盐度限制的缺点,本文研制出一种耐盐耐高温的改性聚丙烯酰胺凝胶堵剂(YN-1),是由改性聚丙烯酰胺与矿化度为10g/L的水配置而成的凝胶体.该堵剂具有较好的耐盐性能和耐温性能,不受地层渗透率的影响,同时还具有较强的耐冲刷性和封堵性,可满足某些高温高盐油田的堵水需要.