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International audience; Piezoelectric materials that generate electrical signals in response to mechanical strain can be used in tissue engineering to stimulate cell proliferation. Poly (vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)), a piezoelectric polymer, is widely used in biomaterial applications. We hypothesized that incorporation of zinc oxide (ZnO )nanoparticles into the P(VDF-TrFE) matrix could promote adhesion, migration, and proliferation of cells, as well as blood vessel formation (angiogenesis). In this study, we fabricated and comprehensively characterized a novel electrospun P(VDF-TrFE)/ZnO nanocomposite tissue engineering scaffold. We analyzed the morphological features of the polymeric matrix by scanning electron microscopy, and utilized Fourier transform infrared spectroscopy, X-ray diffraction, and differential scanning calorimetry to examine changes in the crystalline phases of the copolymer due to addition of the nanoparticles. We detected no or minimal adverse effects of the biomaterials with regard to blood compatibility in vitro, biocompatibility, and cytotoxicity, indicating that P(VDF-TrFE)/ZnO nanocomposite scaffolds are suitable for tissue engineering applications. Interestingly, human mesenchymal stem cells (hMSCs) and human umbilical vein endothelial cells cultured on the nanocomposite scaffolds exhibited higher cell viability, adhesion, and proliferation compared to cells cultured on tissue culture plates or neat P(VDF-TrFE) scaffolds. Nanocomposite scaffolds implanted into rats with or without hMSCs did not elicit immunological responses, as assessed by macroscopic analysis and histology. Importantly, nanocomposite scaffolds promoted angiogenesis, which was increased in scaffolds pre-seeded with hMSCs. Overall, our results highlight the potential of these novel P(VDF-TrFE)/ZnO nanocomposites for use in tissue engineering, due to their biocompatibility and ability to promote cell adhesion and angiogenesis.

Due to low cost and portability of Wi-Fi technologies, wireless network deployment has been widely accepted in the residential environment. The evaluation results of customers’ home wireless network performance level provides a reference for operators to improve their network capacity in order to face the emerging requirement of Wi-Fi service. However, the dynamic nature of Wi-Fi network makes Wi-Fi performance analysis difficult to perform. In this thesis, a Wi-Fi parameter visualization tool is implemented to show users’ Wi-Fi performance in a graphic way. This tool could help operators investigate customers’ Wi-Fi environment to see if performance degradation exists or not. Besides, a machine learning method is used for Wi-Fi performance analysis to predict Wi-Fi throughput. A SVM-based classification model is proposed to work as a prediction function. This function takes Wi-Fi parameters both for target AP and nearby interference APs as input, and output is categorized Wi-Fi throughput, good, medium, poor or very poor. Different SVM kernel functions conducted to evaluate the proposed model and results show that classification accuracy can be up to 0.88. It demonstrates that Wi-Fi throughput could be classified using a simple measurement way and limited Wi-Fi physical parameters. På grund av låg kostnad och hög bärbarhet, för Wi-Fi-teknik, har trådlösa nätverk blivit mycket vanliga i bostadsmiljön. Den stora anvndningen av Wi-Fi-tjänster betyder att operatrerna vill förbättra nätverkstjänsterna, genom att känna till kundernas prestanda fr deras trådlsa nätverk i hemmen. De dynamiska egenskaperna hos Wi-Fi-ntverk gr det dock svårt att utföra analysen av Wi-Fi data. I denna avhandling implementeras ett Wi-Fi-parameter visualiseringsverktyg, för att visa användarnas Wi-Fi-prestanda på ett graskt stt. Det här verktyget kan hjälpa operatörer att underska kundernas Wi-Fi-miljö, för att se om prestanda försämras eller ej. Dessutom föreslås en SVM-baserad klassiceringsmodell för att förutsäga Wi-Fi-genomstrmning. Denna klassiceringsmodell fungerar som en prediktionsfunktion som tar Wi-Fi-parametrar både för den egna accesspunkten och närliggande accesspunkters interferens som input, och för utsignalen kategoriseras datatakten som: bra, medium, fattig eller mycket dålig. Olika SVM-körfunktioner utförda för att utvärdera den föreslagna modellen och resultaten visar att klassiceringsnoggrannheten kan vara upp till 0,88. Det visar att Wi-Fi-datatakten kan klassiceras med ett enkelt mätverktyg och genom att känna till begränsat antal Wi-Fiparametrar.

International audience; Surface material functionalization including layer-by-layer (LbL) polyelectrolyte films with incorporated nanoparticles is a growing field with a wide range of biomedical applications: drug reservoirs, medical devices, or tissue engineering. In parallel, gold nanoparticles (AuNPs) can be grafted by drugs and sensitive molecules using simple protocols. This study shows that AuNP behavior is modified when they are entrapped into three partner LbL films in comparison to the colloidal solution. A polycationic (polyallylamine hydrochloride (PAH)) and a polyanionic (polyacrylic acid (PAA)) polymer is used to build films based on three cycles ((PAH/AuNP/PAA)3). To investigate the interaction with biomolecules and cells, three different films are developed changing the outer layer (either PAH or AuNP or PAA) with the same number of AuNP deposit. The best biocompatibility is observed with a polyacrylic acid outer layer. Due to the high capacity of drug grafting on gold nanoparticles, the results seem promising for the development of nanostructured biomedical devices.

Agricultural eco-efficiency which combines both economic and environmental performance is an effective tool for agricultural sustainability analysis.Taking China′s 30 provinces as case regions,We applied a SBM model of DEA to measure the agricultural eco-efficiency from 1998 to 2009.The SBM model of DEA is non-radical,non-oriented and considers the agricultural non-point source pollution as an undesirable output in the calculating process which is different from the other existing models.Fertilizer,animal,labor,machine,sown area and water consumption were considered as input indicators,provincial agricultural output value and agricultural non-point source pollution were considered as desirable output indicaor and undesirable output indicaor respectively.The main results are summarized as follows:(1)Agricultural eco-efficiency in China during 1998—2009 is 0.499 which is very low,this implies China′s agricultural economic rapid growth is at the expense of natural resources destruction and agriculture environmental pollution,the coordination task of agricultural economic growth and environmental protection and resource saving is very difficult in China;(2)Agricultural eco-efficiency of Beijing,Shanghai,Chongqing,Hainan is equal to one,this demonstrates that these four provinces have efficiency of resources utilization and environment protection for their agricultural economy,but the agricultural eco-efficiency of the other 26 provinces are below one showing that most provinces in China have inefficiency of resources utilization and environment protection for their agricultural economy;(3)Moreover,in order to promote agricultural eco-efficiency in these 26 provinces,the inputs optimization and outputs optimization were designed based on optimization principles.The optimization results show that agricultural output value(agricultural desirable output) has no congestion in all provinces,so the agricultural eco-inefficiency is mostly attributed to inputs and undesirable output.China has enormous potential on the reduction of agricultural non-point source pollution and on the decrease of resource inputs to improve the agricultural eco-efficiency.The eco-efficiency optimization provides deeper insights into the causes of eco-inefficiency and gives further implications on resource and environment protection strategies in China.Our results also showed that the SBM model could be used as a useful tool to reflect the eco-efficiency in a defined region and help governments at various levels to find the most optimized solutions in improving their eco-efficiencies.

Aims and objectives Methods and materials Results Conclusion Personal information References, Aims and objectives: Computed tomography (CT) is widely used in hepatic imaging due to its high resolution and fast data acquisition, in which hepatic contrast-enhanced CT (CECT) is considered as an imaging modality of choice in evaluating liver abnormalities ranging...