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Ironing out Their Differences: Dissecting the Structural Determinants of a Phenylalanine Aminomutase and Ammonia Lyase

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ACS CHEMICAL BIOLOGY 2015年第4期10卷 989-997页

作者： Heberling, Matthew M. Masman, Marcelo F. Bartsch, Sebastian Wybenga, Gjalt G. Dijkstra, Bauke W. Marrink, Siewert J. Janssen, Dick B. Univ Groningen Groningen Biomol Sci & Biotechnol Inst Dept Biochem NL-9747 AG Groningen Netherlands Univ Groningen Groningen Biomol Sci & Biotechnol Inst Biophys Chem Lab NL-9747 AG Groningen Netherlands Univ Groningen Groningen Biomol Sci & Biotechnol Inst Dept Mol Dynam NL-9747 AG Groningen Netherlands

Deciphering the structural features that functionally separate ammonia lyases from aminomutases is of interest because it may allow for the engineering of more efficient aminomutases for the synthesis of unnatural amino acids (e.g., beta-amino acids). However, this has proved to be a major challenge that involves understanding the factors that influence their activity and regioselectivity differences. Herein, we report evidence of a structural determinant that dictates the activity differences between a phenylalanine ammonia lyase (PAL) and aminomutase (PAM). An inner loop region that closes the active sites of both PAM and PAL was mutated within PAM (PAM residues 77-97) in a stepwise approach to study the effects when the equivalent residue(s) found in the PAL loop were introduced into the PAM loop. Almost all of the single loop mutations triggered a lyase phenotype in PAM. Experimental and computational evidence suggest that the induced lyase features result from inner loop mobility enhancements, which are possibly caused by a 3(10)-helix cluster, flanking a-helices, and hydrophobic interactions. These findings pinpoint the inner loop as a structural determinant of the lyase and mutase activities of PAM.

关键词： pralidoxime iodide SHCBP1 gene programmable logic arrays Determinants internal recycling Lyases LRIT1 gene Ironing Ammonia-Lyases

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Nitric oxide is involved in integration of UV-B absorbing compounds among parts of clonal plants under a heterogeneous UV-B environment

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PHYSIOLOGIA PLANTARUM 2015年第2期155卷 180-191页

作者： Liu, Xiao Li, Qian Yue, Ming Zhang, Xiaofei Zhang, Ruichang Zhang, Bing Wang, Ming Northwest Univ Minist Educ Key Lab Resource Biol & Biotechnol Western China Xian 710069 Peoples R China Xian Bot Garden Shaanxi Prov Inst Bot Shaanxi Prov Xian 710061 Peoples R China China Coal Technol & Engn Grp Corp Xian Res Inst Environm Protect Res Inst Xian 710054 Peoples R China

In nature, ultraviolet-B (UV-B) radiation is highly heterogeneous, both spatially and temporally. Plants exposed to UV-B radiation produce UV-B absorbing compounds that function as a protective filter. For clonal plants under heterogeneous UV-B radiation conditions, integration among ramets can allow irradiated ramets to benefit un-irradiated ramets by causing them to increase their UV-B absorbing compounds content. In this study, we evaluated integration between pairs of clonal ramets of Glechoma longituba under heterogeneous or homogeneous UV-B conditions. We determined the levels of UV-B absorbing compounds, nitric oxide (NO) and hydrogen peroxide (H2O2) and measured the activity of phenylalanine ammonia-lyase (PAL) in connected ramet pairs under homogeneous or heterogeneous UV-B conditions. Under heterogeneous UV-B conditions, the UV-B absorbing compounds content increased in leaves of irradiated and un-irradiated ramets, but not in the connecting stolons. The NO content increased in irradiated and un-irradiated leaves and stolons, but the H2O2 content did not. Application of NO synthesis inhibitors and an NO blocker to irradiated ramets blocked the increase in UV-B absorbing compounds and PAL activity in un-irradiated ramets. These results suggested that NO is involved in the integration process for UV-B absorbing compounds among ramets. Our findings suggested that a UV-B-induced increase in NO transmits a signal to un-irradiated ramets via the stolon, leading to an increase in PAL activity and UV-B absorbing compounds content. The internal translocation of signal enables members of clonal networks to function as a whole unit and to mount an efficient defensive response to localized UV-B radiation.

关键词： SHCBP1 gene programmable logic arrays Nitric Oxide Stolon Absorption (physics) Irradiation compounds LRIT1 gene ramet NOBELIUM Beta Rays

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Accelerating Reactive Compatibilization of PE/PLA Blends by an Interfacially Localized Catalyst

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ACS MACRO LETTERS 2015年第1期4卷 30-33页

作者： Thurber, Christopher M. Xu, Yuewen Myers, Jason C. Lodge, Timothy P. Macosko, Christopher W. Univ Minnesota Dept Chem Engn & Mat Sci Minneapolis MN 55414 USA Univ Minnesota Dept Chem Minneapolis MN 55414 USA Oak Ridge Natl Lab Oak Ridge TN 37831 USA Univ Minnesota Characterizat Facil Minneapolis MN 55455 USA

We show catalyst localized at the interface can compatibilize polyethylene (PE) and polylactide (PLA) blends. Telechelic hydroxyl functional PE was synthesized by ring opening metathesis polymerization, which reacted with PLA in melt mixing (shown by adhesion and droplet size reduction). Lewis acid tin catalysts were examined as interfacial reaction promoters, with the goal of interfacial localization. Stannous octoate was shown to localize at the interface by transmission electron microscopy with energy dispersive X-ray spectroscopy and improved dispersion of PLA in PE as compared to uncatalyzed materials and a nonlocalized tin chloride dihydrate.

关键词： programmable logic arrays MELT MIXING 2-ethylhexanoic acid tin(II) salt REACTIVE COMPATIBILISATION COMPATIBILISATION Catalysts acceleration ring opening metathesis polymerization Energy Dispersive X-Ray Spectroscopy Blends Polyethylenes

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A Neural Network Model of Decisions on the Asian Disease Problem

A Neural Network Model of Decisions on the Asian Disease Pro...

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International Joint Conference on Neural Networks (IJCNN)

作者： AlQaudi, Bakur Levine, Daniel S. Lewis, Frank L. Yanbu Ind Coll Yanbu Saudi Arabia Univ Texas Arlington Res Inst Arlington TX 76045 USA Univ Texas Arlington Dept Psychol Arlington TX 76019 USA

ISBN: (纸本)9781479919598

Tversky and Kahneman [1] found that human decisions can be inconsistent across descriptions of the options. An example is the Asian Disease Problem, whereby preferences between two public health programs are different when options are framed in terms of deaths versus lives saved. Several variants of the Asian Disease paradigm and an analogous problem were run [2, 3]: the results showed that the strength of the framing effect depended on whether one of options explicitly contained the possibility of no lives lost or saved. This result was explained by fuzzy trace theory whereby decisions are based not on details of the options but on their gist (underlying meaning). We simulate these results using a neural network model that blends fuzzy trace theory with adaptive resonance theory and contains analogs of orbitofrontal cortex, amygdala, anterior cingulate, and striatum.

关键词： Adaptation models Artificial neural networks Brain modeling programmable logic arrays Utility theory

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Bi-Decomposition using Boolean Relations 18

Bi-Decomposition using Boolean Relations

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18th Euromicro Conference on Digital System Design (DSD)

作者： Bernasconi, Anna Brayton, Robert K. Ciriani, Valentina Trucco, Gabriella Villa, Tiziano Univ Pisa Dipartimento Informat I-56100 Pisa Italy Univ Calif Berkeley Dept EECS Berkeley CA 94720 USA Univ Milan Dipartimento Informat I-20122 Milan Italy Univ Verona Dipartimento Informat I-37100 Verona Italy

ISBN: (纸本)9781467380355

We study three-level implementations where the first two levels represent a standard PLA form with an AND-plane and an OR-plane. This implements a 2m-output SOP. The final stage consists of m two-input programmable LUTs. The PLA outputs are paired so that the LUT outputs implement a set of m given incompletely specified functions (ISFs). Three-level structures have been studied previously, e.g. resulting in AND-OR-AND or AND-OR-XOR implementations. By using the LUT effectively, the composition of the AND-plane can be controlled to implement a PLA which has the optimum phase assignment for maximum cube sharing. For each output, we characterize the problem of all legal implementations of such a model, by defining Boolean relations that capture all the flexibility induced by the final LUT logic. The extra LUT level provides a dimension beyond simple phase assignment. We performed experiments using a Boolean relation minimizer to compare such realizations vs. SOP forms and published three-level forms, comparing areas and delays. To approximate the possible sharing in the PLA, we mapped the 2m PLA logic using SIS. We focused on experiments with two-input Boolean functions not captured by AND-OR-AND or AND-OR-XOR approaches and found good gains in many cases with affordable increases in synthesis runtimes.

关键词： programmable logic arrays Phase assignment three-level Schengen Information System SPECIAL ISOTOPE SEPARATOR small outline package level structure dimensions Flexibility

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Investigating gene expression array with outliers and missing data in bladder cancer

Investigating gene expression array with outliers and missin...

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IEEE International Conference on Bioinformatics and Biomedicine

作者： Chretien, Stephane Guyeux, Christophe Boyer-Guittaut, Michael Delage-Mouroux, Regis Descotes, Francoise Univ Franche Comte Lab Math Besancon 16 Route Gray F-25000 Besancon France Univ Franche Comte CNRS DISC Comp Sci Dept FEMTO ST InstUMR 6174 F-25000 Besancon France Univ Franche Comte EA 3922 IFR133 F-25000 Besancon France Ctr Hosp Lyon Sud Serv Biochim & Biol Mol Sud F-69495 Pierre Benite France

ISBN: (纸本)9781467367981

In this article, we present a methodology to perform selection among genes based on their expression in various groups of patients, in order to find new genetic markers for specific pathologies. Our approach is based on clustering the denoised data and computing a LASSO (Least Absolute Shrinkage and Selection Operator) estimator, in order to select the relevant genes. This latter belongs to the class of penalized regression estimators where the penalty is a multiple of the l(1)-norm of the regression vector. Gene markers of the most severe tumor state are finally provided using the proposed approach.

关键词： programmable logic arrays

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A 3D-Printed PLA Plastic Conical Antenna with Conductive-Paint Coating for RFI Measurements on MeerKAT Site 5

A 3D-Printed PLA Plastic Conical Antenna with Conductive-Pai...

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17th International Conference on Electromagnetics in Advanced Applications (ICEAA) / 5th IEEE-APS Topical Conference on Antennas and Propagation in Wireless Communications (IEEE-APWC)

作者： Andriambeloson, J. A. Wiid, P. G. Univ Stellenbosch Dept Elect & Elect Engn Cnr Baughoek & Bosman Ed ZA-7600 Stellenbosch Western Cape South Africa

ISBN: (纸本)9781479978090

A 3D-printing technique, combined with conductive paints, is investigated for a lowcost methodology in antenna design. The technique is applied on a conical antenna of 41 degrees above a ground-plane using carbon and nickel-based conductive paints. An impedance bandwidth of 20:1 is achieved. Measured normalised-directivity patterns correlate with simulations and the antenna is more than 90% efficient up to 5 GHz.

关键词： conical antennas paint coating ANTENNA antennae Radiofrequency interference Paint painting Ground plane Directivity pattern programmable logic arrays Printing, Three-Dimensional conductivity

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Developing Flexible 3D Printed Antenna Using Conductive ABS Materials

Developing Flexible 3D Printed Antenna Using Conductive ABS ...

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IEEE International Symposium on Antennas and Propagation / USNC/URSI National North American Radio Science Meeting

作者： Mirzaee, Milad Noghanian, Sima Wiest, Lindsey Chang, Isaac Univ N Dakota Dept Elect Engn Grand Forks ND 58201 USA Univ N Dakota Dept Technol Grand Forks ND 58201 USA

ISBN: (纸本)9781479978151

This paper presents the feasibility of conductive acrylonitrile butadiene styrene (ABS) materials in the fabrication of flexible three-dimensional (3D) antennas using additive manufacturing method. To demonstrate this application a bowtie antenna with coplanar waveguide (CPW) feed structure has been designed and measured. The prototype of the antenna has been fabricated using Makerbot r dual 3D printer and flexible polylactic acid (PLA) and ABS filaments for dielectric and conductive parts of the antenna, respectively. To our knowledge, this is the first reported antenna fabricated with conductive ABS material. The dielectric properties of the PLA and ABS filaments have been measured using Agilent performance probe. The fabricated antenna possesses compact size, light-weight and mechanically flexible structure. In addition it achieves wide bandwidth of 24.18 % at the center frequency of 7.81 GHz.

关键词： ABS resins ANTENNA antennae DDX41 gene Antilock Braking Systems conductivity center frequency bow-tie antennas 3D Printer programmable logic arrays Microstrip antennas FLEXIBLE fabrication coplanar waveguides

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Low-Power Race-Free programmable logic arrays

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IEEE JOURNAL OF SOLID-STATE CIRCUITS 2009年第3期44卷 935-946页

作者： Samson, Giby Clark, Lawrence T. Arizona State Univ Dept Elect Engn Tempe AZ 85287 USA

Conventional programmable logic arrays (PLAs) implement both the AND and OR logic planes with dynamic NOR gates. They are fast, regular in structure and easy to program. However, they have high power dissipation and suffer from an inherent timing race that increases design effort, reduces circuit robustness in the presence of variations, and adversely impacts performance. In this paper, a PLA which implements the AND plane as a hierarchical combination of dynamic NAND gates and retains the dynamic NOR gate based OR plane is presented. The NAND-NOR PLA architecture completely eliminates the critical timing race between the logic planes and has significantly lower power dissipation than the conventional PLA. Simulated energy-delay product of an optimized design on a foundry 130 nm low standby power process shows that the proposed circuit architecture has 43% lower energy-delay product than the conventional MA design. The fabricated circuits have been tested fully functional on silicon demonstrating a maximum operating frequency or 1.61 GHz;at V-DD = 1.6 V.

关键词： Dynamic logic logic timing programmable logic arrays transistor leakage transistor variation

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Inversion schemes for sublithographic programmable logic arrays

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IET COMPUTERS AND DIGITAL TECHNIQUES 2009年第6期3卷 625-642页

作者： Gojman, B. Manem, H. Rose, G. S. DeHon, A. Univ Penn Philadelphia PA 19104 USA NYU Polytech Inst MetroTech Ctr 5 Brooklyn NY 11201 USA

A programmable logic array (PLA) needs its inputs available in both the positive and negative polarities. In lithographic-scale VLSI PLAs, programmable array logics (PALs) and programmable logic devices (PLDs) a buffer and inverter at the PLA input typically produces both polarities from a single polarity input. However, the extreme regularity required for sublithographic designs has driven nanoscale architectures to consider alternate solutions. Consequently, the authors compare three schemes: one based on producing both polarities in a restoration stage (selective inversion), one based on a local inversion stage and one based on a full dual-rail logic implementation. The authors develop a mapping flow for the dual-rail logic and quantify its cost in both logical product terms and physical implementation area and also develop area and timing models for all three schemes. Mapping benchmarks from the Toronto 20 set, the authors are able to show that the local inversion scheme is faster (less than one-fifth the latency), lower energy (one-half the energy) and comparable size to the selective inversion scheme and faster (less than half the latency), smaller (one-third of the area) and lower energy (one-ninth the energy) than the dual-rail scheme.

关键词： logic circuits programmable logic devices VLSI inverter lithography Lithography (semiconductor technology) buffer local inversion Semiconductor integrated circuits sublithographic programmable logic arrays inversion schemes logic gates buffer circuits programmable logic arrays

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