检索结果-内蒙古大学图书馆

Optical Molecular Probes, Imaging and Drug Delivery, OMP 2013

作者： Chen, Leng-Chun Lloyd, William R. Kuo, Shiuhyang Kimd, Hyungjin Myra Marcelo, Cynthia L. Feinberg, Stephen E. Mycek, Mary-Ann Dept. of Biomedical Engineering Ann Arbor MI 48109-2099 United States Applied Physics Program Ann Arbor MI 48109-2099 United States Oral and Maxillofacial Surgery Ann Arbor MI 48109-2099 United States Dept. of Biostatistics Ann Arbor MI 48109-2099 United States Plastic Surgery University of Michigan Ann Arbor MI 48109-2099 United States

Label-free nonlinear optical microscopy was employed to monitor primary human cells in tissue-engineered constructs. Novel quantitative analysis techniques were developed that successfully distinguished viable from no... 详细信息

ISBN: (纸本)9781557529664

关键词： Tissue

来源：评论

学校读者我要写书评

暂无评论

Suspended Si/air high contrast subwavelength gratings for long-wavelength infrared reflectors

引用

Proceedings of SPIE - The International Society for Optical Engineering 2013年 8633卷

作者： Foley, Justin M. Phillips, Jamie D. Applied Physics Program University of Michigan 450 Church St. Ann Arbor MI 48109-1040 United States Electrical Engineering and Computer Science Department University of Michigan 1301 Beal Ave. Ann Arbor MI 48109-2122 United States

ISBN: (纸本)9780819494023

We report broadband reflectance in the long-wavelength infrared (LWIR, 8-12 μm) utilizing suspended-Si, high-index-contrast subwavelength gratings (HCGs). Iterative design optimization using finite element analysis software has been performed accounting for silicon's wavelength-dependent index of refraction and extinction coefficient. Grating arrays were fabricated using commercial silicon-on-insulator (SOI) substrates, photolithography and reactive ion etching; subsequent selective wet etching of SiO2was used to provide suspended Si/air gratings. Fourier transform infrared (FTIR) spectroscopy demonstrates broadband, polarization-dependent reflectance between 8.5 and 12 μm, which agrees with the simulated response. © 2013 SPIE.

关键词： Infrared radiation Diffraction gratings Finite element method Fourier transform infrared spectroscopy Hyperspectral imaging Infrared devices Reactive ion etching Reflection Refractive index Silica Silicon on insulator technology Silicon oxides Broadband reflector Filter HCG reflector High contrast gratings Long wavelength infrared LWIR

来源：评论

学校读者我要写书评

暂无评论

Unwinding and rewinding the nucleosome inner turn: Force dependence of the kinetic rate constants

引用

Physical Review E 2013年第1期87卷 012710-012710页

作者： S. G. J. Mochrie A. H. Mack D. J. Schlingman R. Collins M. Kamenetska L. Regan Integrated Graduate Program in Physical and Engineering Biology Yale University New Haven Connecticut 06520 USA Department of Applied Physics Yale University New Haven Connecticut 06520 USA Department of Physics Yale University New Haven Connecticut 06520 USA Department of Molecular Biophysics and Biochemistry Yale University New Haven Connecticut 06520 USA Department of Chemistry Yale University New Haven Connecticut 06520 USA

A simple model for the force-dependent unwinding and rewinding rates of the nucleosome inner turn is constructed and quantitatively compared to the results of recent measurements [A. H. Mack et al., J. Mol. Biol. 423, 687 (2012)]. First, a coarse-grained model for the histone-DNA free-energy landscape that incorporates both an elastic free-energy barrier and specific histone-DNA bonds is developed. Next, a theoretical expression for the rate of transitions across a piecewise linear free-energy landscape with multiple minima and maxima is presented. Then, the model free-energy landscape, approximated as a piecewise linear function, and the theoretical expression for the transition rates are combined to construct a model for the force-dependent unwinding and rewinding rates of the nucleosome inner turn. Least-mean-squares fitting of the model rates to the rates observed in recent experiments rates demonstrates that this model is able to well describe the force-dependent unwinding and rewinding rates of the nucleosome inner turn, observed in the recent experiments, except at the highest forces studied, where an additional ad hoc term is required to describe the data, which may be interpreted as an indication of an alternate high-force nucleosome disassembly pathway, that bypasses simple unwinding. The good agreement between the measurements and the model at lower forces demonstrates that both specific histone-DNA contacts and an elastic free-energy barrier play essential roles for nucleosome winding and unwinding, and quantifies their relative contributions.

关键词： CHROMATIN HISTONES LEAST squares CHEMICAL bonds ANALYSIS of DNA

来源：评论

学校读者我要写书评

暂无评论

Efficient linear programming algorithm to generate the densest lattice sphere packings

引用

Physical Review E 2013年第6期87卷 063303-063303页

作者： Étienne Marcotte Salvatore Torquato Department of Physics Princeton University Princeton New Jersey 08544 USA Department of Chemistry Princeton University Princeton New Jersey 08544 USA Program in Applied and Computational Mathematics Princeton University Princeton New Jersey 08544 USA Princeton Institute of the Science and Technology of Materials Princeton University Princeton New Jersey 08544 USA

Finding the densest sphere packing in d-dimensional Euclidean space Rd is an outstanding fundamental problem with relevance in many fields, including the ground states of molecular systems, colloidal crystal structures, coding theory, discrete geometry, number theory, and biological systems. Numerically generating the densest sphere packings becomes very challenging in high dimensions due to an exponentially increasing number of possible sphere contacts and sphere configurations, even for the restricted problem of finding the densest lattice sphere packings. In this paper we apply the Torquato-Jiao packing algorithm, which is a method based on solving a sequence of linear programs, to robustly reproduce the densest known lattice sphere packings for dimensions 2 through 19. We show that the TJ algorithm is appreciably more efficient at solving these problems than previously published methods. Indeed, in some dimensions, the former procedure can be as much as three orders of magnitude faster at finding the optimal solutions than earlier ones. We also study the suboptimal local density-maxima solutions (inherent structures or “extreme” lattices) to gain insight about the nature of the topography of the “density” landscape.

关键词： LINEAR programming BIOLOGICAL systems COLLOIDAL crystals CODING theory DISCRETE geometry NUMBER theory

来源：评论

学校读者我要写书评

暂无评论

Nearly hyperuniform network models of amorphous silicon

引用

Physical Review B 2013年第24期87卷 245204-245204页

作者： Miroslav Hejna Paul J. Steinhardt Salvatore Torquato Department of Physics Princeton University Princeton New Jersey 08544 USA Princeton Center for Theoretical Science Princeton University Princeton New Jersey 08544 USA Department of Chemistry Princeton Institute for the Science and Technology of Materials and Program in Applied and Computational Mathematics Princeton University Princeton New Jersey 08544 USA

We introduce the concept of nearly hyperuniform network (NHN) structures as alternatives to the conventional continuous random network (CRN) models for amorphous tetrahedrally coordinated solids, such as amorphous silicon (a-Si). A hyperuniform solid has a structure factor S(k) that approaches zero as the wavenumber k→0. We define a NHN as an amorphous network whose structure factor S(k→0) is smaller than the liquid value at the melting temperature. Using a novel implementation of the Stillinger-Weber potential for the interatomic interactions, we show that the energy landscape for a spectrum of NHNs includes a sequence of local minima with an increasing degree of hyperuniformity [smaller S(k→0)] that is significantly below the frozen-liquid value and that correlates with other measurable features in S(k) at intermediate and large k and with the width of the electronic band gap.

关键词： SPECTRUM analysis AMORPHOUS silicon WAVENUMBER INTERATOMIC angles ELECTRONIC band structure

来源：评论

学校读者我要写书评

暂无评论

RF-Penetrable PET insert for simultaneous PET/MR imaging

引用

EJNMMI physics 2014年第SUPPL 1期1卷 A5页

作者： Brian J Lee Alexander M Grant Chen-Ming Chang Craig S Levin Department of Radiology Stanford University Stanford CA 94305 USA. Molecular Imaging Program at Stanford (MIPS) Stanford CA 94305 USA. Department of Mechanical Engineering Stanford University Stanford CA 94305 USA. Department of Bioengineering Stanford University Stanford CA 94305 USA. Department of Applied Physics Stanford University Stanford CA 94305 USA. Department of Physics Stanford University Stanford CA 94305 USA. Department of Electrical Engineering Stanford University Stanford CA 94305 USA.

来源：评论

学校读者我要写书评

暂无评论

Designer spin systems via inverse statistical mechanics

引用

Physical Review B 2013年第13期88卷 134104-134104页

作者： Robert A. DiStasio, Jr. Étienne Marcotte Roberto Car Frank H. Stillinger Salvatore Torquato Department of Chemistry Princeton University Princeton New Jersey 08544 USA Department of Physics Princeton University Princeton New Jersey 08544 USA Princeton Institute for the Science and Technology of Materials Princeton University Princeton New Jersey 08544 USA Program in Applied and Computational Mathematics Princeton University Princeton New Jersey 08544 USA

In this work, we extend recent inverse statistical-mechanical methods developed for many-particle systems to the case of spin systems. For simplicity, we focus in this initial study on the two-state Ising model with radial spin-spin interactions of finite range (i.e., extending beyond nearest-neighbor sites) on the square lattice under periodic boundary conditions. Our interest herein is to find the optimal set of shortest-range pair interactions within this family of Hamiltonians, whose corresponding ground state is a targeted spin configuration such that the difference in energies between the energetically closest competitor and the target is maximized. For an exhaustive list of competitors, this optimization problem is solved exactly using linear programming. The possible outcomes for a given target configuration can be organized into the following three solution classes: unique (nondegenerate) ground state (class I), degenerate ground states (class II), and solutions not contained in the previous two classes (class III). We have chosen to study a general family of striped-phase spin configurations comprised of alternating parallel bands of up and down spins of varying thicknesses and a general family of rectangular block checkerboard spin configurations with variable block size, which is a generalization of the classic antiferromagnetic Ising model. Our findings demonstrate that the structurally anisotropic striped phases, in which the thicknesses of up- and down-spin bands are equal, are unique ground states for isotropic short-ranged interactions. By contrast, virtually all of the block checkerboard targets are either degenerate or fall within class III solutions. The degenerate class II spin configurations are identified up to a certain block size. We also consider other target spin configurations with different degrees of global symmetries and order. Our investigation reveals that the solution class to which a target belongs depends sensitively on the nature

关键词： INVERSE functions LATTICE dynamics STRUCTURAL optimization ANTIFERROMAGNETIC materials GROUND state (Quantum mechanics) ANISOTROPIC crystals

来源：评论

学校读者我要写书评

暂无评论

Designer spin systems via inverse statistical mechanics. II. Ground-state enumeration and classification

引用

Physical Review B 2013年第18期88卷 184432-184432页

作者： Étienne Marcotte Robert A. DiStasio, Jr. Frank H. Stillinger Salvatore Torquato Department of Physics Princeton University Princeton New Jersey 08544 USA Department of Chemistry Princeton University Princeton New Jersey 08544 USA Princeton Institute for the Science and Technology of Materials Princeton University Princeton New Jersey 08544 USA Program in Applied and Computational Mathematics Princeton University Princeton New Jersey 08544 USA

In the first paper of this series [DiStasio, Jr., Marcotte, Car, Stillinger, and Torquato, Phys. Rev. B 88, 134104 (2013)], we applied inverse statistical-mechanical techniques to study the extent to which targeted spin configurations on the square lattice can be ground states of finite-ranged radial spin-spin interactions. In this sequel, we enumerate all of the spin configurations within a unit cell on the one-dimensional integer lattice and the two-dimensional square lattice up to some modest size under periodic boundary conditions. We then classify these spin configurations into those that can or cannot be unique classical ground states of the aforementioned radial pair spin interactions and found the relative occurrences of these ground-state solution classes for different system sizes. As a result, we also determined the minimal radial extent of the spin-spin interaction potentials required to stabilize those configurations whose ground states are either unique or degenerate (i.e., those sharing the same radial spin-spin correlation function). This enumeration study has established that unique ground states are not limited to simple target configurations. However, we also found that many simple target spin configurations cannot be unique ground states.

关键词： SPIN-lattice relaxation ONE-dimensional conductors SPIN-spin interactions GROUND state (Quantum mechanics) PRODUCT attributes

来源：评论

学校读者我要写书评

暂无评论

Using the Population‐Shift Mechanism to Rationally Introduce “Hill‐type” Cooperativity into a Normally Non‐Cooperative Receptor†

引用

Angewandte Chemie 2014年第36期126卷

作者： Anna J. Simon Alexis Vallée‐Bélisle Francesco Ricci Herschel M. Watkins Kevin W. Plaxco Biomolecular Science and Engineering Program UC Santa Barbara Santa Barbara CA 93106 (USA) Département de Chimie Université de Montréal QC (Canada) Dipartimento di Scienze e Tecnologie Chimiche University of Rome Tor Vergata Via della Ricerca Scientifica (Italy) Current address: Department of Applied Physics Stanford University (USA) Department of Chemistry and Biochemistry UC Santa Barbara (USA)

Allosteric cooperativity, which nature uses to improve the sensitivity with which biomolecular receptors respond to small changes in ligand concentration, could likewise be of use in improving the responsiveness of artificial biosystems. Thus motivated, we demonstrate here the rational design of cooperative molecular beacons, a widely employed DNA sensor, using a generalizable population‐shift approach in which we engineer receptors that equilibrate between a low‐affinity state and a high‐affinity state exposing two binding sites. Doing so we achieve cooperativity within error of ideal behavior, greatly steepening the beacon’s binding curve relative to that of the parent receptor. The ability to rationally engineer cooperativity should prove useful in applications such as biosensors, synthetic biology and “smart” biomaterials, in which improved responsiveness is of value.

关键词： Allosterie DNA Kooperative Effekte Sensoren Synthesebiologie

来源：评论

学校读者我要写书评

暂无评论

Corrosion Behavior of Copper Patina in Presence of Marine Biofouling

引用

ECS Meeting Abstracts 2013年第20期MA2013-02卷

作者： Lucien Petrova Veleva Daniel Lopez Sauri Juan Luis Lopez CINVESTAV-IPN (Center for Investigation and Advanced Study) CINVESTAV-IPN Merida Doctor program in Physical Chemistry Applied Physics Department CINVESTAV-IPN Merida Applied Physics Department

Abstract not Available.

关键词：

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：