Microfabrication and Test of a Three-Dimensional Polymer Hydro-focusing Unit for Flow Cytometry Applications

This paper details a novel three-dimensional (3D) hydro-focusing micro cell sorter for micro flow cytometry applications. The unit was microfabricated by means of SU-8 3D lithography. The 3D microstructure for coaxial sheathing was designed, microfabricated, and tested. Three-dimensional hydro-focusing capability was demonstrated with an experiment to sort labeled tanned sheep erythrocytes (red blood cells). This polymer hydro-focusing microstructure is easily microfabricated and integrated with other polymer microfluidic structures

Environmental Compensation Effect and Synergistic Mechanism of Optimized Nitrogen Management Increasing Nitrogen Use Efficiency in Indica Hybrid Rice

Modern rice cultivation relies heavily upon inorganic nitrogen fertilization. Effective fertilizer management is key to sustainable agricultural development. Field and pot trials were conducted in 2014–2016, including a 15N-labeled urea pot experiment (2014) to investigate mechanism by which optimized nitrogen fertilizer application (OFA) increases nitrogen utilization efficiency (NUE). Results showed that the applied nitrogen recovery efficiencies with OFA were 71.71%, 110.17%, and 51.38% higher than those obtained with traditional nitrogen fertilizer application (TFA) in 2014, 2015, and 2016, respectively. These improvements are attributed mainly to the high recovery efficiency rates derived from spikelet-developing and spikelet-promoting fertilizer applications at the jointing stage and 15–20 d after jointing. Under OFA, the amount of nitrogen fertilizer applied at the early stages was half that used in TFA, which not only promoted the absorption of soil nitrogen, but also reduced nitrogen loss to the environment, as the NUE of basal and tillering fertilizer was only about 22%. Nitrogen applied during the panicle differentiation stage increased the expression of ATM1;1, a NH4+ transporter in roots. This effect significantly improved the uptake of nitrogen derived from fertilizer from jointing to heading stage. Up-regulation of the expression and activity of GS and GOGAT at the panicle differentiation and grain-filling stages promoted nitrogen translocation from vegetative organs to reproductive organs. The uptake of nitrogen derived from fertilizer increased from 22.51% in TFA to 35.58% in OFA. Nevertheless, rice absorbs most of the nitrogen it requires from the soil. The OFA treatment could effectively utilize the environmental compensation effect, promote the absorption and transport of nitrogen, and ultimately lead to improvement in NUE. Future research should aim to understand the soil nitrogen supply capacity in order to apply nitrogenous fertilizer in such a way that it sustains the nitrogen balance

Fast degrading polymer networks based on carboxymethyl chitosan

[EN] In this work macroporous membrane for mesenchymal stem cells, MSCs, transplant has been developed. The membranes support cell seeding and proliferation and completely degrade in less than one week in "in vitro" culture. The biodegradable material is a polymer network based on carboxymethyl chitosan( a water soluble modification of chitosan) crosslinked by poly(epsilon-caprolactone) PCL, fragments which are susceptible to hydrolytic degradation. Synthesis was performed in solution in a common solvent for the two components of the network. The gel fraction was assessed by extraction in selective solvents. Physical characterization of networks of varying composition included water sorption capacity and the crystallinity of poly(epsilon-caprolactone) in the network. In this way polymer networks are synthesized that lose between 66 +/- 5% and 89 +/- 1% of their mass when immersed in water for 28 days. The same weight loss is attained in enzymatic medium in only 4 days. Porcine bone marrow MSCs were seeded in macroporous membranes to show cell viability, and proliferation up to 7 days culture when the biomaterial is completely dissolved in the medium.Gamiz Gonzalez, MA.; Guldrís-Prada, P.; Antolinos Turpín, CM.; Ródenas Rochina, J.; Vidaurre, A.; Gómez Ribelles, JL. (2017). Fast degrading polymer networks based on carboxymethyl chitosan. Materials Today Communications. 10:54-66. doi:10.1016/j.mtcomm.2017.01.005S54661

Microfabrication of pre-aligned fiber bundle couplers using ultraviolet lithography of SU-8

AbstractThis paper describes the design, microfabrication and testing of a pre-aligned array of fiber couplers using direct UV-lithography of SU-8. The fiber coupler array includes an out-of-plane refractive microlens array and two fiberport collimator arrays. With the optical axis of the pixels parallel to the substrate, each pixel of the microlens array can be pre-aligned with the corresponding pixels of the fiberport collimator array as defined by the lithography mask design. This out-of-plane polymer 3D microlens array is pre-aligned with the fiber collimator arrays with no additional adjustment and assembly required, therefore, it helps to dramatically reduce the running cost and improve the alignment quality and coupling efficiency. In addition, the experimental results for the fiber couplers are also presented and analyzed

A Bus Passenger Flow Prediction Model Fused with Point-of-Interest Data Based on Extreme Gradient Boosting

Bus operation scheduling is closely related to passenger flow. Accurate bus passenger flow prediction can help improve urban bus planning and service quality and reduce the cost of bus operation. Using machine learning algorithms to find the rules of urban bus passenger flow has become one of the research hotspots in the field of public transportation, especially with the rise of big data technology. Bus IC card data are an important data resource and are more valuable to passenger flow prediction in comparison with manual survey data. Aiming at the balance between efficiency and accuracy of passenger flow prediction for multiple lines, we propose a novel passenger flow prediction model based on the point-of-interest (POI) data and extreme gradient boosting (XGBoost), called PFP-XPOI. Firstly, we collected POI data around bus stops based on the Amap Web service application interface. Secondly, three dimensions were considered for building the model. Finally, the XGBoost algorithm was chosen to train the model for each bus line. Results show that the model has higher prediction accuracy through comparison with other models, and thus this method can be used for short-term passenger flow forecasting using bus IC cards. It plays a very important role in providing decision basis for more refined bus operation management

The research of device for measuring film thickness of intelligent coating machine

Ion beam sputtering machine uses computer to real time monitor the change of film thickness in the preparation process of soft X ray multilayer element fabrication. It solves the problems of uneven film thickness and too thick film thickness and so on, which exist in the original preparation process. The high-precision quartz crystal converts film thickness measurement into frequency measurement. The equal precision frequency meter based on FPGA measures the frequency. It can reduce the signal delay and interference signal of discrete components, accordingly improving the accuracy of measurement. Then it sents the count value to the host computer through the single chip microcomputer serial port. It calculates and displays the value by the GUI of LabVIEW. The experimental results show that, the relative measurement error can be decreased to 1/10, i.e., the measurement accuracy can be improved by more than ten times

A Distributed Real-Time Transcoding CDN System Design and Performance Simulation Study

Content Delivery Network (CDN) technology is one of the core technologies for performance optimization of mobile WEB applications, but it often encounters bottlenecks in video storage. In this paper, based on studying the basic technical model of distributed real-time transcoding CDN, we propose an overall technical architecture of a distributed real-time transcoding CDN system, present the business process of distributed real-time transcoding CDN resource negotiation in the model, design a resource storage policy model and algorithm, including the hot storage ratio resource storage value evaluation method and storage resource allocation algorithm. Through simulation experiments, we verify the technical efficiency of the distributed real-time transcoding CDN system by simulation experiments

The research of device for measuring film thickness of intelligent coating machine

Ion beam sputtering machine uses computer to real time monitor the change of film thickness in the preparation process of soft X ray multilayer element fabrication. It solves the problems of uneven film thickness and too thick film thickness and so on, which exist in the original preparation process. The high-precision quartz crystal converts film thickness measurement into frequency measurement. The equal precision frequency meter based on FPGA measures the frequency. It can reduce the signal delay and interference signal of discrete components, accordingly improving the accuracy of measurement. Then it sents the count value to the host computer through the single chip microcomputer serial port. It calculates and displays the value by the GUI of LabVIEW. The experimental results show that, the relative measurement error can be decreased to 1/10, i.e., the measurement accuracy can be improved by more than ten times