The effects of stainless steel finish on Salmonella Typhimurium attachment,biofilm formation and sensitivity to chlorine

Bacterial colonization and biofilm formation on stainless steel (SS) surfaces can be sources for cross contamination in food processing facilities, possessing a great threat to public health and food quality. Here the aim was to demonstrate the influence of surface finish of AISI 316 SS on colonization, biofilm formation and susceptibility of Salmonella Typhimurium to disinfection.     

Self-assembled magnetic bead biosensor for measuring bacterial growth and antimicrobial susceptibility testing

Bacterial antibiotic resistance is one of the major concerns of modern healthcare worldwide, and the development of rapid, growth-based, antimicrobial susceptibility tests is key for addressing it. The cover image shows a self-assembled asynchronous magnetic bead rotation (AMBR) biosensor developed for rapid detection of bacterial growth. Using the biosensors, the minimum inhibitory concentration of a clinical E. coli isolate can be measured within two hours, where currently tests take 6-24 hours. A 16-well prototype is also constructed for simple and robust observation of the self-assembled AMBR biosensors.     

Synthesis of biomaterial thin films by pulsed laser technologies: Electrochemical evaluation of bioactive glass-based nanocomposite coatings for biomedical applications

The surface of biomedical titanium implants has been covered with thin films of bioactive glass and bioactive glass + poly(methyl methacrylate nanocomposite) in order to increase the resistance to corrosion and improve the bioactivity of their area in contact with bone tissue. To this purpose Pulsed Laser Deposition and Matrix Assisted Pulsed Laser Evaporation with an excimer laser source have been applied.The layer assessments under conditions that simulate their biological interaction with the human body fluids and resistance to degradation have been studied by electrochemical polarization and electrochemical impedance spectroscopy. The poly(methyl methacrylate) addition to bioglass has reduced the bone ability to bond but resulted in a significant increase of the shielding efficiency against corrosion of the applied coatings.The obtained results support the application of bioactive glass and composite bioactive glass + poly(methyl methacrylate) coatings for the development of advanced highly stable implants and prostheses that cannot be affected by corrosion.     

Solvent-adoptable polymer Ni/NiCo alloy nanochains: highly active and versatile catalysts for various organic reactions in both aqueous and nonaqueous media

The synthesis of solvent-adoptable monometallic Ni and NiCo alloy nanochains by a one-pot solution phase reduction method in the presence of poly(4-vinylphenol) (PVPh) is demonstrated. The elemental compositions of the as-prepared alloys are determined by inductively coupled plasma optical emission spectroscopy (ICP-OES) and energy-dispersive X-ray spectroscopy (EDS), which are matching well with the target compositions. The morphology analysis by TEM and FESEM confirms that the nanochains are made up of organized spherical monometallic Ni or bimetallic NiCo alloy nanoparticles (NPs). However, there is no nanochain formation when the alloy is prepared without the polymer PVPh. A possible mechanism for the formation of such NiCo alloy nanochains is discussed. The X-ray diffraction and selected area electron diffraction patterns reveal that the Ni/NiCo alloys are polycrystalline with fcc structure. The obtained Ni or NiCo alloy nanostructures are ferromagnetic with very high coercivity. The polymer Ni/NiCo alloy nanochains are dispersible in both water and organic media that makes them versatile enough to use as catalysts in the reactions carried out in both types of media. The catalytic activities of these Ni/NiCo alloy nanochains are extremely high in the borohydride reduction of p-nitrophenol in water. In organic solvents, these nanochains can act as efficient catalysts, under ligand-free condition, for the C-S cross-coupling reactions of various aryl iodides and aryl thiols for obtaining the corresponding cross-coupled products in good to excellent yield up to 96%. The NiCo nanochain also successfully catalyzes the C-O cross-coupling reaction in organic medium. A possible mechanism for NiCo alloy nanochain-catalyzed cross-coupling reaction is proposed.     

Investigation of electron-hole generation in MOS capacitors on 4H SiC

This paper investigates electron-hole generation in n-type MOS capacitors on 4H-SiC with the gate oxide directly grown in either 100% NO or 10% N/sub 2/O. High-temperature capacitance-transient measurements were used to determine and compare the contributions of carrier generation in the bulk and at the SiO/sub 2/-SiC interface. The effective generation rate in the bulk is similar in the MOS capacitors with either type of gate oxide, whereas the effective surface-generation rate is much lower in the case of oxides grown in 100% NO. Moreover, the effective surface-generation rate in these oxides is reduced to the level that is comparable to the effective bulk-generation rate. This result demonstrates the high quality of MOS capacitors with the gate oxide directly grown in 100% NO.     

销售计划的线性规划模型

本文建立了一个适应于化肥生产连续而销售呈现季节性的产品销售计划的线性规划模型,提出了求解该模型的方法,并指出成功地应用该模型制订销售计划的关键是价格预测和储存费用的测算。同时提出了停车检修时间安排的原则。     

Effects of ultrasound on the synthesis of zeolites: a review

In this review, effects of ultrasound on the synthesis of different zeolites are studied. Ultrasound has been applied in crystallization because of its significant influences on the induction periods and nucleation. The effects of ultrasound assisted aging process for different zeolites compared with the effects of static aging, in some cases with microwave assisted aging, stirring aging and synthesis without any aging. Application of ultrasound can influence the size and morphology of the crystals, crystallization time and the crystallinity of the zeolites. The observations indicate that application of ultrasound can shorten the crystallization time. Application of ultrasound also improves crystallinity of the synthesized zeolites. Moreover, use of ultrasound assisted aging leads to altered morphologies and size of the particles.     

MXene/PDMS composite foam with regulatable cell structures for improved EMI shielding performance

The construction of conductive network and the design of material structure are the key points of polymer-based shielding materials. Herein, we reported a MXene/PDMS composite foam material with adjustable cell structure and high efficiency electromagnetic interference (EMI) shielding. Few-layered MXene is used as a conductive filler to construct three-dimensional conductive networks by in situ chemical etching. Meanwhile, a series of polystyrene microspheres with different sizes were prepared by applying suspension polymerization method as templates to introduce different cell sizes and densities for PDMS-based materials. The density and EMI shielding performance of composites can be improved by adjusting the cell structure. Compared with the unfoamed MXene/PDMS composites, the composite foam in this work not only reduces the material density greatly but also improves the microwave absorption performance with smaller cell size. This method provides a simple and effective guide for changing material density and absorbing mechanism by introducing cell structure into polymer-based materials in the future.