Liyuan Chen  Steven D. Brown 《Journal of Chemometrics》2014,28(6):523-538

Analysis and modeling of spatial data are of considerable interest in many applications. However, the prediction of geographical features from a set of chemical measurements on a set of geographically distinct samples has never been explored. We report a new, tree‐structured hierarchical model for the estimation of geographical location of spatially distributed samples from their chemical measurements. The tree‐structured hierarchical modeling used in this study involves a set of geographic regions stored in a hierarchical tree structure, with each nonterminal node representing a classifier and each terminal node representing a regression model. Once the tree‐structured model is constructed, given a sample with only chemical measurements available, the predicted regional location of the sample is gradually restricted as it is passed through a series of classification steps. The geographic location of the sample can be predicted using a regression model within the terminal subregion. We show that the tree‐structured modeling approach provides reasonable estimates of geographical region and geographic location for surface water samples taken across the entire USA. Further, the location uncertainty, an estimate of a probability that a test sample could be located within a pre‐estimated, joint prediction interval that is much smaller than the terminal subregion, can also be assessed. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

    

Jason L. Nyrop  Arash Soheili  Rong Xiang  Fanyu Meng  Jacob H. Waldman  Xiujuan Jia  Rubina Giarre Parmar  Benjamin W. Thuronyi  J. Michael Williams  Lisa DiMichele  Michel Journet  Bonnie J. Howell  Bing Mao  Ian W. Davies  Steven L. Colletti  Laura Sepp‐Lorenzino  Erin N. Guidry 《Journal of polymer science. Part A, Polymer chemistry》2014,52(8):1119-1129

Synthetic polymers represent a modifiable class of materials that can serve as adjuvants to address challenges in numerous biomedical and medicinal chemistry applications including the delivery of siRNA. Polymer‐based therapeutics offer unique challenges in both synthesis and characterization as compared to small molecule therapeutics. The ability to control the structure of the polymer is critical in creating a therapeutic. Reported herein, are batch and flow polymerization processes to produce amphiphilic terpolymers through a Lewis acid BF₃OEt₂‐catalyzed polymerization. These processes focus on controlling reaction variables, which affect polymer structure in this rapid, exothermic, nonliving cationic polymerization. In addition to analytical characterization of the polymers, the in vivo activity of the polymer‐siRNA conjugates is also highlighted—demonstrating that the method of synthesis does affect the in vivo activity of the resulting polymer conjugate. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1119–1129  相似文献   

    

Hsu‐Feng Lee  Po‐Hsun Wang  Yi‐Chiang Huang  Wen‐Hung Su  Ram Gopal  Chun Che Lee  Steven Holdcroft  Wen‐Yao Huang 《Journal of polymer science. Part A, Polymer chemistry》2014,52(18):2579-2587

A series of sterically‐encumbered, sulfonated, poly(arylene ether) copolymers were synthesized and their proton conductivity examined. The series was prepared by copolymerizing a novel monomer, 2″,3″,5″,6″‐tetraphenyl‐[1,1′:4',1″:4″,1″':4″',1″″‐quinquephenyl]‐4,4″″‐diol, with 4,4'‐difluorobenzophenone and bisphenol A. Subsequent sulfonation and solution casting provided membranes possessing ion exchange capacities of 1.9 to 2.7 mmol/g and excellent mechanical properties (Young's modulus, 0.2–1.2 GPa; tensile strength, 35–70 MPa; elongation at break, 62–231%). Water uptake ranged from 34 to 98 wt% at 80 °C/100% RH. Proton conductivities ranged between 0.24 to 16 mS/cm at 80 °C/60% RH, and 3 to 167 mS/cm at 80 °C/95% RH. TEM analysis of the polymers, in the dehydrated state, revealed isolated spherical aggregates of ions, which presumably coalesce when hydrated to provide highly conductive pathways. The strategy of using highly‐encumbered polymer frameworks for the design of mechanically‐robust and dimensionally‐stable proton conducting membranes is demonstrated. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 2579‐2587  相似文献   

    

Steven E. F. Kleijn  Stanley C. S. Lai  Marc T. M. Koper  Patrick R. Unwin 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(14):3630-3660

  相似文献   

    

Clemens Kremer  Christian Witte  Steven L. Neale  Julien Reboud  Michael P. Barrett  Jonathan M. Cooper 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(3):907-907

  相似文献   

    

Martin Hintersteiner  Jrg Kallen  Mario Schmied  Christine Graf  Thomas Jung  Gemma Mudd  Steven Shave  Hubert Gstach  Manfred Auer 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(17):4410-4414

  相似文献   

    

Steven V. Ley  Daniel E. Fitzpatrick  Rebecca M. Myers  Claudio Battilocchio  Richard. J. Ingham 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2015,127(35):10260-10275

  相似文献   

    

Melissa H. Lash  Jahnelle C. Jordan  Laura C. Blevins  Morgan V. Fedorchak  Steven R. Little  Joseph J. McCarthy 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2015,127(20)

  相似文献   

    

Louis Vanduyfhuys  Steven Vandenbrande  Toon Verstraelen  Rochus Schmid  Michel Waroquier  Veronique Van Speybroeck 《Journal of computational chemistry》2015,36(13):1015-1027

QuickFF is a software package to derive accurate force fields for isolated and complex molecular systems in a quick and easy manner. Apart from its general applicability, the program has been designed to generate force fields for metal‐organic frameworks in an automated fashion. The force field parameters for the covalent interaction are derived from ab initio data. The mathematical expression of the covalent energy is kept simple to ensure robustness and to avoid fitting deficiencies as much as possible. The user needs to produce an equilibrium structure and a Hessian matrix for one or more building units. Afterward, a force field is generated for the system using a three‐step method implemented in QuickFF. The first two steps of the methodology are designed to minimize correlations among the force field parameters. In the last step, the parameters are refined by imposing the force field parameters to reproduce the ab initio Hessian matrix in Cartesian coordinate space as accurate as possible. The method is applied on a set of 1000 organic molecules to show the easiness of the software protocol. To illustrate its application to metal‐organic frameworks (MOFs), QuickFF is used to determine force fields for MIL‐53(Al) and MOF‐5. For both materials, accurate force fields were already generated in literature but they requested a lot of manual interventions. QuickFF is a tool that can easily be used by anyone with a basic knowledge of performing ab initio calculations. As a result, accurate force fields are generated with minimal effort. © 2015 Wiley Periodicals, Inc.  相似文献   

    

Huawei Zhang  Steven T. Loveridge  Karen Tenney  Phillip Crews 《Natural product research》2016,30(11):1262-1265

A new alkaloid, 3-dodecyl pyridine containing a terminal cyano group (1), was isolated from the methanol extract of an Indonesia marine sponge Haliclona sp. Its chemical structure was determined by a combination of spectroscopic methods, including 1D and 2D NMR. Bioassay results indicated that compound 1 had moderate cytotoxity against tumour cell lines A549, MCF-7 and Hela with IC₅₀ values of 41.8, 48.4 and 33.2 μM, respectively.  相似文献