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Effect of lipase treatment on the biocompatibility of microbial polyhydroxyalkanoates

JOURNAL OF MATERIALS SCIENCE-MATERIALS IN MEDICINE 2002年第9期13卷 849-854页

作者： Zhao, K Yang, X Chen, GQ Chen, JC Tsinghua Univ Dept Biol Sci & Biotechnol Microbiol Lab Beijing 100084 Peoples R China

Films made from microbial polyesters polyhydroxybutyrate (PHB) and poly(hydroxybutyrate-co-hydroxyhexanoate) (PHBHHx) were treated by lipases and NaOH solution. The change of the polyester biocompatibility was evaluated by inoculating mouse fibroblast cell line L929 on films of PHB, PHBHHx and their blends. Polylactic acid (PLA) was used as a control. It was found that untreated PHB and PLA films gave a poor support to the growth of L929 cells, viable cell density ranged from 0.1x10(4) to 0.7x10(4) per ml only. While films of pure PHBHHx and PHB blended with PHBHHx showed improved biocompatibility, viable cell density observed increased from 9.6x10(2) to 6x10(4) on blended films of PHB/PHBHHx in ratios of 0.9/0.1 to 0/1, respectively. This result showed PHBHHx has a better biocompatibility compared with PHB. Films of PHB, PLA and the blends treated with lipases and 1 N NaOH, respectively, showed an improved ability to support cell growth. Biocompatibility of PHB was approximately the same as PLA after the treatment, while PHBHHx and its dominant blends showed improved biocompatibility compared with PLA. The sensitivity of the treatments was reduced when PHBHHx content increased in the PHB/PHBHHx blends. All three lipase treatments demonstrated more biocompatibility increase on all the films compared with the results of NaOH treatment. Scanning electron microscopy showed that PHB films changed its surface from multi-porous to rough non-porous after the lipase or NaOH treatment. While PHBHHx films showed little change after these treatments. The results showed that the polyester surface morphology played an important role in affecting cell attachment and growth on these materials. (C) 2002 Kluwer Academic Publishers.

关键词： biomaterial compatibility NCTC clone 929 cell line prohibitin Films programmable logic arrays Cell Density Lipase Blends Sodium Hydroxide

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Physical-Layer Authentication Using Multiple Channel-Based Features

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IEEE TRANSACTIONS ON INFORMATION FORENSICS AND SECURITY 2021年 16卷 2356-2366页

作者： Xie, Ning Chen, Junjie Huang, Lei Shenzhen Univ Coll Elect & Informat Engn Guangdong Key Lab Intelligent Informat Proc Shenzhen 518060 Peoples R China Shenzhen Univ Coll Elect & Informat Engn Shenzhen Key Lab Media Secur Shenzhen 518060 Peoples R China Shenzhen Univ Coll Elect & Informat Engn Guangdong Engn Res Ctr Posit Sensing & Detect Shenzhen 518060 Peoples R China

This paper concerns the problem of authenticating the transmitter without a secret key. In comparison with traditional cryptographic-based authentication mechanisms, the Physical-Layer Authentication (PLA) has the following advantages: high security, low complexity, and high compatibility, since it exploits intrinsic and unique features of the physical layer to authenticate the transmitter rather than using a secret key. The prior channel-based PLA schemes use a quantization algorithm to deal with multiple channel-based features for simplicity. However, there are two main limitations in the prior schemes: performance loss due to quantization error and the difficulty of obtaining the optimal thresholds in closed-form. In this paper, we propose two multiple Channel Impulse Response (CIR) based PLA schemes to effectively overcome the aforementioned limitations of the prior schemes. The first scheme uses multiple CIRs to realize the PLA, which is named as the Multiple CIRs PLA (MCP) scheme. The MCP scheme has better authentication performance than the prior schemes, since it avoids to use a quantization algorithm. The second scheme further improves the authentication performance by exploiting the channel correlation coefficient, which is named as the Enhanced Multiple CIRs PLA (EMCP) scheme. We provide rigorous performance analysis of two proposed schemes. We implemented the proposed schemes and conducted extensive performance comparisons through simulations. Our experimental results show that the closed-form expressions of the theoretical results of the proposed schemes perfectly match the corresponding simulation results. The EMCP scheme has the best authentication performance and the MCP scheme is the second one, whereas the prior scheme is the worst one. As the SNR or the channel correlation coefficient declines, the performance gap among various schemes gradually increases.

关键词： Authentication programmable logic arrays Quantization (signal) Receivers Cryptography MIMO communication Correlation Physical layer authentication channel-based features quantization algorithm performance analysis fading channels

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Load Sharing Strategy for Autonomous AC Microgrids Based on FPGA Implementation of ADALINE&FLL

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IEEE TRANSACTIONS ON ENERGY CONVERSION 2014年第3期29卷 663-672页

作者： Guzman, Cristina Cardenas, Alben Agbossou, Kodjo Univ Quebec Trois Rivieres Hydrogen Res Inst Trois Rivieres PQ G9A 5H7 Canada Univ Quebec Trois Rivieres Dept Genie Elect & Genie Informat Trois Rivieres PQ G9A 5H7 Canada

Paralleled operation of voltage-source inverters (VSIs) is currently achieved by using voltage/frequency droop control techniques which requires the knowledge of the system parameters. Otherwise, centralized control techniques with robust communication among VSIs controllers are also used. This paper presents a new control strategy which allows the load sharing between the power sources of an ac microgrid without centralized controller or any communication among the VSIs;only local measurements of voltage and output current are used. The dispatchable sources (e.g., fuel cells) of the microgrid are operated using voltage control with a direct droop scheme, and the nondispatchables or intermittent ones (e.g., wind turbine generators) are operated using power control with a complementary inverse droop scheme (D-Droop + I-Droop). The number of operating sources can be changed online without any modification needed on the VSI controllers. The proposed VSI controllers are based on the variable frequency adaptive linear neuron with frequency-locked loop for the VSIs system synchronization, voltage/power and signal estimation. Experimental results using field-programmable gate array devices for the implementation of each VSI control in themicrogrid test bench demonstrated the validity of the proposition.

关键词： Distributed power generation frequency-locked loops neural networks power generation control programmable logic arrays smart grids very large scale integration voltage control

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Plasticizing Effect of Glyceryl Tribenzoate, Dipropylene Glycol Dibenzoate, and Glyceryl Triacetate on Poly(lactic acid)

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POLYMER ENGINEERING AND SCIENCE 2016年第12期56卷 1399-1406页

作者： Wan, Tong Lin, Yanyan Tu, Yapeng Tianjin Univ Sci & Technol TEDA Coll Mat Sci & Chem Engn Tianjin 300457 Peoples R China

The aim of this article is to compare the plasticizing effect of different plasticizers on poly(lactic acid) (PLA) including glyceryl tribenzoate (GTB), dipropylene glycol dibenzoate (DPGDB), and glyceryl triacetate (GTA). The chemical structures of plasticizers are characterized by 1 H-nuclear magnetic resonance. PLA is blended with GTA, DPGDB, and GTB at various contents by using a twin screw extruder. Plasticizing effect of three plasticizers are evaluated by comparison of thermal property, storage stability, melt plasticizing coefficient, thermal degradation, and water vapor permeability. This study reveals that PLA/DPGDB exhibits better physical properties than the others do. DPGDB containing ether and ester groups may therefore render good compatibility with PLA. (C) 2016 Society of Plastics Engineers

关键词： programmable logic arrays B4GALT1 gene Glycols Triacetin physical properties Plasticizing Plasticizers poly(lactic acid)

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TESTING AND APPLICATIONS OF INVERTER-FREE PLAS

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IEEE DESIGN & TEST OF COMPUTERS 1987年第6期4卷 30-40页

作者： RAJSKI, J AGARWAL, VK McGill University

The testing properties of inverter-free PLAs make them ideal for application to totally self-checking and easily testablecircuits. After a class of test patterns and masking relations for these new patterns are determined, a complete test setfor single and multiple crosspoint faults can be easily generated. Moreover, the procedure does not require any fault *** code space inputs detect all single and multiple faults in PLAs for totally self-checking circuits, even if the faultsare not unidirectional. The test results can be used to analyze easily testable PLAs. With minor hardware changes in one-inputdecoder PLAs, the personality matrix will serve as a complete test set.

关键词： programmable logic arrays Circuit testing Circuit faults Automatic testing Test pattern generators Circuit simulation Electrical fault detection Fault detection Hardware Decoding

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INTERVAL GRAPH ALGORITHMS FOR 2-DIMENSIONAL MULTIPLE FOLDING OF ARRAY-BASED VLSI LAYOUTS

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IEEE TRANSACTIONS ON COMPUTER-AIDED DESIGN OF INTEGRATED CIRCUITS AND SYSTEMS 1994年第10期13卷 1201-1222页

作者： HO, KC VRUDHULA, SBK UNIV ARIZONA DEPT ELECT & COMP ENGNTUCSONAZ 85721

Folding or topological compaction of array-based VLSI layouts is an important optimization step that is carried out after logic synthesis. In this paper, a new approach to two-dimensional multiple folding of array-based VLSI layouts is presented. From the specification of the problem a pair of intersection graphs is created. We show that any pair of interval graphs that contain the intersection graphs as spanning subgraphs corresponds to a set of feasible foldings. Next, a complete and exact characterization of the folding problem is presented. In particular, it is shown that the set of all feasible foldings associated with a given pair of interval graphs corresponds to the set of independent colorings of a pair of compatibility graphs. The compatibility graphs are derived from a pair of interval graphs that contain the intersection graphs as spanning subgraphs. Thus, minimizing the area of a layout is tantamount to finding a pair of compatibility graphs such that the product of their chromatic numbers is minimum. As important as minimizing the area of a layout is, the ability to rapidly generate compact layouts over a wide range of aspect ratios is often equally, if not more, important. The interval graph-based formulation of the folding problem permits a controlled and systematic generation of compact layouts with varying aspect ratios. Efficient and provably correct algorithms to generate compact layouts that have a given number of rows or a given number of columns within their minimum and maximum possible values are given. The basic theory and methods are extended to include I/O and other types of constraints. Finally, the results of experiments that were carried out on a large number of benchmark problems are given. These results are compared with those obtained by previously reported methods.

关键词： Very large scale integration programmable logic arrays logic arrays Compaction Control systems Constraint theory

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Multi-camera systems - Calibration and applications

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IEEE SIGNAL PROCESSING MAGAZINE 1999年第3期16卷 55-65页

作者： Pedersini, F Sarti, A Tubaro, S

In this article, we present some simple and effective techniques for accurately calibrating a multi-camera acquisition system. The proposed methods were proven to be capable of accurate results even when using very simple calibration target sets and low-cost imaging devices, such as standard TV-resolution cameras connected to commercial frame-grabbers. In fact, the performance of our calibration approach yielded results that were about the same as that of other traditional calibration methods based on large 3D target sets. The proposed calibration strategy is based on a multi-view multi-camera approach. This was based on the analysis of a number of views of a simple calibration target-set placed in different (unknown) positions. Furthermore, the method is based on a self-calibration approach, which can refine the a priori knowledge of the world coordinates of the targets (even when such information is very poor) while estimating the parameters of the camera model. Finally we proposed a method, to make the calibration technique adaptive through the analysis of natural scene features, allowing the camera parameters to hold accurate throughout the acquisition session in the presence of parameter drift.

关键词： Cameras Nonlinear distortion Calibration Layout Optical distortion Lenses Nonlinear optics Pixel Polynomials programmable logic arrays

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Implementation of Statistical Learning Methods to Develop Guidelines for the Design of PLA-Based Composites with High Tensile Strength Values

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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH 2019年第8期58卷 3478-3489页

作者： Alakent, Burak Soyer-Uzun, Sezen Bogazici Univ Dept Chem Engn TR-34342 Istanbul Turkey

Statistical analysis employing regression trees is utilized, for the first time, for a PLA-based biocomposite system aiming to extract knowledge in order to guide researchers toward intelligent selection of experimental conditions for desired tensile strength values. For the construction of the database, experimental data on PLA-based composites from past publications was collected using online sources such as ScienceDirect, Elsevier, ACS, and Google. The final data set that was built using 26 papers (out of similar to 50 initially screened) published between 1999 and 2018 contained 135 experimental data points. The response variable was selected as tensile strength, and 23 features regarding composite synthesis were included involving manufacturing method and temperature for compounding and testing, molecular weight of the PLA used, chemical composition of the composite, and type of filler employed in synthesis. Unbiased cross validation error of the regression tree was found to be 12-17 MPa, with coefficient of determination for prediction (R-p(2)) value equal to 0.5-0.7 showing moderate to -high prediction accuracy. Results indicated the following: (i) The feature in top node of the tree is the method used for manufacturing/testing rather than the type of filler employed and the composition of the composite (i.e., PLA content). PLA-based composites manufactured by solvent casting and direct mixing displayed significantly lower tensile strength values whereas biocomposites manufactured through other techniques involving compression, injection, melt blending, hot pressing, and aqueous suspension result in relatively higher tensile strength values. (ii) The molecular weight of the PLA had a significant influence in predicting the final tensile strength of the composite. The composites manufacatured employing PLA with molecular weight in the range of 275-400 kDa displayed high tensile strength values. (iii) The temperature employed during test specimen preparation fo

关键词： Composites top nodes programmable logic arrays Fillers Molecular weights high-tensile strength Tensile Strength test temperature manufacturing method response variable

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A 6K-GATE GAAS GATE ARRAY WITH A NEW LARGE-NOISE-MARGIN SLCF CIRCUIT

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IEEE JOURNAL OF SOLID-STATE CIRCUITS 1987年第5期22卷 755-761页

作者： TERADA, T IKAWA, Y KAMEYAMA, A KAWAKYU, K SASAKI, T KITAURA, Y ISHIDA, K NISHIHORI, K TOYODA, N VLSI Research Center Toshiba Corporation Kawasaki Japan

A 6 K-gate GaAs gate array has been successfully designed and fabricated using a novel large-noise-margin Schottky-diode level-shifter capacitor-coupled FET logic (SLCF) circuitry and a WN/SUB x/ gate selfaligned lightly doped drain (LDD) structure GaAs MESFET process. Chip size was 8.0/spl times/8.0 mm/SUP 2/. A basic cell can be programmed as an SLCF inverter, a two-input NOR, or a two-input NAND gate. The unloaded propagation delay time was 76 ps/gate a 1.2-mW/gate power dissipation. The increases in delay time due to various loading capacitances were 10 ps/fan-in, 45 ps/fan-out, and 0.64 ps/IF. A 16-b serial-to-parallel-to-serial (S/P/S) data-conversion circuit was constructed on the gate array as an application example. A maximum operation frequency of 852 MHz was achieved at a 952-mW power dissipation, including I/O buffers.

关键词： Gallium arsenide logic arrays Power dissipation Optical arrays programmable logic arrays FETs logic design logic circuits MESFET circuits Inverters

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Adduction of ammonium to polylactides to modify their dissociation behavior in collision-induced dissociation

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RAPID COMMUNICATIONS IN MASS SPECTROMETRY 2018年第5期32卷 423-430页

作者： Chendo, Christophe Phan, Trang N. T. Rollet, Marion Gigmes, Didier Charles, Laurence Aix Marseille Univ CNRS Federat Sci Chim Marseille FR 1739 Marseille France Aix Marseille Univ CNRS ICR UMR 7273 Marseille France

RationaleThe goal of this work was to modify the dissociation pathways of polylactide (PLA) holding benzyl and hydroxyl terminations, in order to circumvent coincidence of product ions generated during collisional activation of sodiated chains, which prevented their reliable characterization. MethodsBenzyl-, hydroxyl-terminated PLAs were ionized as ammonium adducts in positive ion mode electrospray and subjected to collision-induced dissociation (CID). Tandem mass spectrometry (MS/MS) experiments were conducted in a quadrupole time-of-flight (QTOF) instrument for safe assignment of product ions based on their elemental composition derived from accurate mass measurements. ResultsAdduction of ammonium to PLAs was found to induce chain fragmentation via charge-assisted processes, in great contrast to the charge-remote mechanisms experienced by sodiated molecules. The main reaction produced ions containing the termination only, hence allowing straightforward end-group determination. Other minor pathways were studied in detail to establish dissociation rules for ammoniated PLAs. Some reactions were found to be end-group specific, highlighting the higher reactivity of ammonium than alkali ion adducts. ConclusionsChanging the usually employed sodium-cationizing agent to ammonium was shown to induce dramatic changes in the CID behavior of PLAs. This was a simple and efficient approach to address issues encountered for end-group analysis of the particular PLA studied here.

关键词： elemental composition Adduction programmable logic arrays charge injection devices collisional activation Polylactides ammonium Ions

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