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In order to improve the flame retardancy of knitted cotton fabrics and investigate the flame-retardant mechanism of the system formed by ammonium polyphosphate (APP) and chitosan (CS), flame-retardant knitted cotton fabrics coated with APP and CS were successfully prepared by layer by layer assembly. APP and CS formed the intumescent flame-retardant system, in which CS acted as the carbon source agent and APP acted as both the acid source and foaming agent. The surface micromorphologies before and after flaming of coated knitted cotton fabrics were exploited by scanning electron microscopy. The flammability, combustion behaviors, thermal degradation properties and flame-retardant mechanism of this system were investigated by vertical burning test, cone calorimetry test and thermogravimetric analysis coupled with Fourier transform infrared analysis in N2 atmosphere, respectively. Compared with the control sample, the deposition of APP and CS endowed the knitted cotton fabrics with improved flame retardancy, higher residual chars, lower heat release rate and total heat release, while increased the smoke production. Improved flame-retardant behaviors are attributed to the thermally stable residual chars, more release of inflammable gases and potential free radical scavengers (PO·) in the gaseous products, named the combination of the condensed-phase and gaseous-phase flame-retardant mechanism. [ABSTRACT FROM AUTHOR]

Micro-droplet deposition manufacture is a novel direct metal rapid prototyping for building the miniaturized parts. In this paper, the relationship between the droplet diameter and the operating parameters is investigated to obtain the optimal condition for the accurate droplet generation. The droplet generator is designed to adjust the parameters such as the infinitesimal disturbance and the jet velocity. Experiments with the different materials have been conducted to study the feasibility of the accurate droplet generation for the manufacturing. Spherical and uniform water micro-droplets within 2.4% variation are generated using an orifice diameter of 150 μm, and tin–lead alloy droplets are produced with an orifice diameter of 100 μm in the argon environment. The results show that the generator can produce accurate micro-droplets which meet the requirements of fabricating the miniaturized parts. [ABSTRACT FROM AUTHOR]

Abstract  To investigate the antifouling secondary metabolites from marine-derived fungi, we used bioassay-guided column chromatography techniques, such as HPLC, to separate and purify compounds from Cladosporium sp. F14. Extensive spectral analyses including 1D NMR spectra and MS were employed for structure elucidation of the compounds. Antilarval activity of the compounds was evaluated in settlement inhibition assays with laboratory-reared Balanus amphitrite and Bugula neritina larvae, while antibacterial activity was assessed with disc diffusion bioassay on growth inhibition of six marine bacterial species. In total, nine compounds were obtained. Among them, 3-phenyl-2-propenoic acid, cyclo-(Phe-Pro) and cyclo-(Val-Pro) had various antibacterial activities against three fouling bacteria, furthermore, 3-phenyl-2-propenoic acid and bis(2-ethylhexyl)phthalate effectively inhibited larval settlement of B. neritina and B. amphitrite larvae, respectively, indicating that the two compounds are potential natural antifouling agents. [ABSTRACT FROM AUTHOR]

DNA sequencing analysis was used to investigate genetic alterations in therpoB, katG, andinhAregulatory region andembBin 66Mycobacterium tuberculosisisolates recovered from Central China. Of the 36 multidrug-resistant isolates, 33 (92%) had mutations in the amplified region ofrpoB. The most frequent mutation (58%, 19/36) was S531L (TCG→TTG). At least one mutation was found in thekatGandinhAregulatory region in 83% (30/36) of the multidrug-resistant isolates, and mutations atkatGcodon 315 were identified in 78% (28/36). Alterations atembB306 may not confer resistance to EMB, andembB306 mutants were more frequently accompanied byrpoBmutations (100%, 16/16) than bykatG315 mutations (75%, 12/16). Our results show that geographic variation in the molecular genetic mechanism is responsible for drug resistance in multidrug-resistantM. tuberculosis. This observation will facilitate the development of a rapid molecular drug resistance screening approach for drug-resistantM. tuberculosis. [ABSTRACT FROM AUTHOR]

As a new metal forming technology, the liquid infiltration and semi-solid extrusion process can produce various composite parts, such as tubes, bars, and shaped products, in a single process. In this paper, the liquid infiltration and semi-solid extrusion process for forming a composite tube is simulated by means of thermal rigid-plastic quasi-coupling FEM method. The key technologies such as the handling of liquid phase zone, the transition between liquid and solid phase zones, the grid re-meshing method and the establishment of the boundary condition have also been studied. Based on the FEM simulation software developed by the authors and the grid re-meshing technology, the distribution of stress field, strain field and deformation force in the liquid infiltration and semi-solid extrusion process for forming composite tubes are obtained. The deformation force simulation results accord with the experimental data, indicating the reliability of the system. Therefore, the present research is theoretically valuable in the product quality control and the process parameter choice. [ABSTRACT FROM AUTHOR]