pH值响应性透明质酸纳米粒的制备及作为阿霉素载体的研究

通过化学交联法合成组氨酸修饰透明质酸耦合物(His-HA),制备载阿霉素纳米粒,分析其pH值响应性和抗肿瘤特征.研究显示,随着pH值的降低(7.4～5.5),纳米粒的粒径增大(230～780nm),zeta电位升高,载药纳米粒的体外释放量增加.细胞毒性实验显示粒径＜300nm的载药纳米粒具更高的毒性.细胞摄入实验表明,阿霉素通过受体介导的胞吞和载药纳米粒的胞外释放两种途径被细胞摄入.以上研究显示组氨酸修饰透明质酸纳米粒具有显著的pH值响应性,具备作为阿霉素药物载体的应用前景.     

Characterization of germanium-doped silica layers deposited by flame-hydrolysis

The optical properties of germanium-doped silica layers deposited by flame-hydrolysis have been investigated by analyzing the effective refractive indices of the modes using an inverse-WKB (Wentzel–Kramers–Brillouin) approach followed by an optimization algorithm. The shape obtained for the refractive index profile is consistent with the compositional and density characterization, performed by X-ray photoelectron spectroscopy (XPS) and X-ray reflectivity, respectively. We believe that the origin of the non-uniformity was the high-temperatures to which the as-deposited soot is subjected in order to obtain fully consolidated, high-optical quality films.     

A validated strip-based lateral flow assay for the confirmation of sheep-specific PCR products for the authentication of meat

Molecular methods, such as PCR and real-time PCR, have been developed to detect species in meat and meat products. Despite good specificity and sensitivity, they are not widely implemented in food control programs due to complex operation or financial reasons. In the present study, a simple, rapid and affordable method, Sheep-PCR-Strip [Sheep specific polymerase chain reaction-Strip], was developed for the authentic identification of raw and heat-treated mutton. The assay is based on PCR amplification of sheep DNA, followed by detection of the PCR product by a strip format; the result can be read within 5 min by the naked eye. There is a real advantage of the strip approach rather in the reduced time (5 min versus electrophoresis) and avoidance of chemicals (e.g. ethidiumbromide). The sensitivity of the Sheep-PCR-Strip test was established to be 0.01% for the detection of adulterated meat; the limit of detection (LOD) was up to 0.01 pg of sheep DNA. The assay was also specific for sheep, and no cross-reactions were observed in other non-target species. It is a promising new tool for sheep identification and can be rapidly modified for other meat detection and widely used for solving problems related to food quality assurance, species authentication and traceability.     

Aggregation-induced emission type thermally activated delayed fluorescent materials for high efficiency in non-doped organic light-emitting diodes

Aggregation-induced emission (AIE) type thermally activated delayed fluorescent (TADF) emitters were developed by asymmetric substitution of donor moieties to a diphenylsulfone acceptor. The AIE properties of the TADF emitters increased the quantum efficiency of the non-doped TADF devices and asymmetric substitution was more effective than symmetric substitution to enhance the quantum efficiency of the non-doped devices.     

The fluorescence property of PNA encapsulated in the pores of oriented silicalite-1 film prepared on MSS

Large-scale high-quality silicalite-1 films were prepared on monocrystal silica slice (MSS) by hydrothermal method. The films are b-oriented crystals perpendicular to the MSS substrate. Using such film as host material, PNA is encapsulated into the channels of the zeolite by physical vapor deposition. When pumped by 488 nm laser, PNA/silicalite-1 film showed strong fluorescence property.     

Model-based analysis of a twin-screw wet granulation system for continuous solid dosage manufacturing

Implementation of twin-screw granulation in a continuous from-powder-to-tablet manufacturing line requires process knowledge development. This is often pursued by application of mechanistic models incorporating the underlying mechanisms. In this study, granulation mechanisms considered to be dominant in the kneading element regions of the granulator i.e., aggregation and breakage, were included in a one-dimensional population balance model. The model was calibrated using the experimentally determined inflow granule size distribution, and the mean residence time was used as additional input to predict the outflow granule size distribution. After wetting, the first kneading block caused an increase in the aggregation rate which was reduced afterwards. The opposite was observed in case of the breakage rate. The successive kneading blocks lead to a granulation regime separation inside the granulator under certain process conditions. Such a physical separation between the granulation regimes is promising for future design and advanced control of the continuous granulation process.     

Tough,transparent, biocompatible and stretchable thermoplastic copolymer with high stability and processability for soft electronics

Materials with a variety of required properties, including stretchability, toughness, optical transparency, biocompatibility, processability, and recyclability are in great demand for soft electronics. Creation of such materials, however, has been hampered due to the challenges of balancing these properties. Herein, we report intrinsically stretchable thermoplastic copolymers with a random sequence of hard and soft domains in the polyimide backbone in which their superior traits are harnessed to enable the properties of the copolymer tunable and balanced. We obtained a tough and stretchable copolymer with high optical transparency, biocompatibility, thermal and chemical stability, and low water vapor transmission rate. In addition, the polymer is recyclable and shows excellent processability, allowing for the fabrication of fibers, thin films, and molded parts for soft electronics. Furthermore, the utility of the copolymer was successfully demonstrated for a wearable temperature sensor on the stretchable copolymer and a copolymer-based fully stretchable sweat collection patch, suggesting that they have great potential in soft electronics.     

Source detection: Influence of the Doerbecker’s noise reduction algorithm; Simulation in the case of binaural cochlear implant coding

Cochlear implant (CI) provides good auditory performances in quiet, but recognition in noisy environments is still a challenge for CI users. Bilateral hearing can improve speech perception; it has been shown with normal hearing aids, but how source localization is affected is still an open question.In this study source localization is studied in the case of a binaural cochlear implant coding. Signal was received on the two ears and then processed using the classical noise reduction algorithm, suggested by Doerbecker and based on the spectral properties of the signal. Two correction strategies, Ephreim & Malah and Scalart, have been inserted in the processing chain.Tests were conducted, “in simulation” with 20 normal hearing listeners who received a cochlear implant coded signal. An analytic interpretation of the results offers a frame to quantify the different contributions.Results show that the Doerbecker’s algorithm affects the source localization. This effect was lowered when a percentage of the input signal was re-injected into the system. Both correction strategies were equivalent.     

Cement formation by microbial poly(γ-glutamic acid) and fluoroalumino-silicate glass

The feasibility of using microbial poly(γ-glutamic acid) (γ-PGA) in cement formation was analyzed. FT–IR and elemental analyses by energy-dispersive spectroscopy (EDS), indicate that calcium and aluminum carboxylates are formed after the reaction of γ-PGA with fluoroalumino-silicate glass powder. The effect of the formulation variables, i.e., (polymer + glass) / liquid ratio (P / L), glass / polymer ratio (G / P), the average glass particle size and the molecular mass of γ-PGA, on the compressive strength is discussed. A maximum compressive strength value of 130 MPa was obtained when cement samples were aged for 7 days. The compressive strength was achieved with a P / L ratio of 2.5 g/ml, a G / P ratio of 2.5 : 1, an average glass particle size of 1 μm and a γ-PGA molecular mass (M ¯w) of 115 000.     

硒的生理功能及其对畜禽动物性能和肉质的影响研究进展

微量元素硒不仅是人体必需营养元素之一,也是动物生长发育必不可少的元素,与动物许多重要的生理学功能密切相关。肉类作为人体摄入硒的主要途径,其硒含量普遍较低。通过向动物饲料中添加硒补充剂,可以有效增加可食组织中硒的沉积,这是改善人类饮食中硒摄入的一种有效方法,同时硒对动物体的影响也引起国内外学者的广泛关注。本文综述硒的生理功能和作用,分析国内外开展硒对畜禽动物性能及肉品质影响的研究现状,包括途径、可能的机理以及存在的问题,以期为硒在动物营养、肉质改善及富硒肉制品的生产开发中的应用提供参考。