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Dongye Xing, Yanjun Hou, Haijun Niu
A series of difluoroboron β-diketonate complexes, containing the indon-β-diketonate ligand carrying methyl or methoxyl substituents was synthesized. The crystal structures of the complexes were confirmed by single crystal X-ray diffraction studies. The fluorescence properties of compounds were studied in solution state, solid state and on PMMA polymer matrix. The photophysical data of compounds 2a-2d exhibited strong fluorescence and photostability under the ultraviolet light (Hg lamp). The complex 2b showed higher fluorescence intensity in solution state as compared to other complexes of the series...
December 6, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Zhonghua Kuang, Ziru Sang, Xiaohui Wang, Xin Fu, Ning Ren, Xianming Zhang, Yunfei Zheng, Qian Yang, Zhanli Hu, Junwei Du, Dong Liang, Xin Liu, Hairong Zheng, Yongfeng Yang
PURPOSE: The performance of current small animal PET scanners is mainly limited by the detector performance and depth encoding detectors are required to develop PET scanner to simultaneously achieve high spatial resolution and high sensitivity. Among all depth encoding PET detector approaches, dual-ended readout detector has the advantage to achieve the highest depth of interaction (DOI) resolution and spatial resolution. Silicon photomultiplier (SiPM) is believed to be the photodetector of the future for PET detector due to its excellent properties as compared to the traditional photodetectors such as photomultiplier tube (PMT) and avalanche photodiode (APD)...
December 9, 2017: Medical Physics
Marco Antonio Seiki Kadowaki, Paula Higasi, Mariana Ortiz de Godoy, Rolf A Prade, Igor Polikarpov
Cellobiohydrolases hydrolyze cellulose, a linear polymer with glucose monomers linked exclusively by β-1,4 glycosidic linkages. The widespread hydrogen bonding network tethers individual cellulose polymers forming crystalline cellulose, which prevent the access of hydrolytic enzymes and water molecules. The most abundant enzyme secreted by Myceliophthora thermophila M77 in response to the presence of biomass is the cellobiohydrolase MtCel7A, which is composed by a GH7-catalytic domain (CD), a linker and a CBM1-type carbohydrate binding module...
December 8, 2017: FEBS Journal
Wenpei Gao, Jianbo Wu, Aram Yoon, Ping Lu, Liang Qi, Jianguo Wen, Dean J Miller, James C Mabon, William L Wilson, Hong Yang, Jian-Min Zuo
Atomic motion at grain boundaries is essential to microstructure development, growth and stability of catalysts and other nanostructured materials. However, boundary atomic motion is often too fast to observe in a conventional transmission electron microscope (TEM) and too slow for ultrafast electron microscopy. Here, we report on the entire transformation process of strained Pt icosahedral nanoparticles (ICNPs) into larger FCC crystals, captured at 2.5 ms time resolution using a fast electron camera. Results show slow diffusive dislocation motion at nm/s inside ICNPs and fast surface transformation at μm/s...
December 8, 2017: Scientific Reports
Hehua Liu, Xiang Yu, Yiqing Chen, Jing Zhang, Baixing Wu, Lina Zheng, Phensinee Haruehanroengra, Rui Wang, Suhua Li, Jinzhong Lin, Jixi Li, Jia Sheng, Zhen Huang, Jinbiao Ma, Jianhua Gan
In addition to storage of genetic information, DNA can also catalyze various reactions. RNA-cleaving DNAzymes are the catalytic DNAs discovered the earliest, and they can cleave RNAs in a sequence-specific manner. Owing to their great potential in medical therapeutics, virus control, and gene silencing for disease treatments, RNA-cleaving DNAzymes have been extensively studied; however, the mechanistic understandings of their substrate recognition and catalysis remain elusive. Here, we report three catalytic form 8-17 DNAzyme crystal structures...
December 8, 2017: Nature Communications
Eva Navrátilová, Eva Tihlaříková, Vilém Neděla, Pavla Rovnaníková, Jaroslav Pavlík
In the study of lime as the basic component of historical mortars and plasters, four lime putties prepared from various kinds of lime of various granulometry and by various ways of preparation were evaluated. The rheological properties and micro-morphologic changes, growing of calcite crystals, and rate of carbonation were monitored. The lime putty prepared from lump lime achieves the best rheological properties, yield stress 214.7 Pa and plastic viscosity 2.6 Pa·s. The suitability of this lime putty was checked by testing the development of calcium hydroxide and calcite crystals using scanning electron microscopy and environmental scanning electron microscopy...
December 8, 2017: Scientific Reports
Jian Su, Shuai Yuan, Hai-Ying Wang, Lan Huang, Jing-Yuan Ge, Elizabeth Joseph, Junsheng Qin, Tahir Cagin, Jing-Lin Zuo, Hong-Cai Zhou
Metal-organic frameworks (MOFs) that respond to external stimuli such as guest molecules, temperature, or redox conditions are highly desirable. Herein, we coupled redox-switchable properties with breathing behavior induced by guest molecules in a single framework. Guided by topology, two flexible isomeric MOFs, compounds 1 and 2, with a formula of In(Me2NH2)(TTFTB), were constructed via a combination of [In(COO)4]- metal nodes and tetratopic tetrathiafulvalene-based linkers (TTFTB). The two compounds show different breathing behaviors upon the introduction of N2...
December 8, 2017: Nature Communications
Yin Fang, Yuanwen Jiang, Mathew J Cherukara, Fengyuan Shi, Kelliann Koehler, George Freyermuth, Dieter Isheim, Badri Narayanan, Alan W Nicholls, David N Seidman, Subramanian K R S Sankaranarayanan, Bozhi Tian
Large-scale assembly of individual atoms over smooth surfaces is difficult to achieve. A configuration of an atom reservoir, in which individual atoms can be readily extracted, may successfully address this challenge. In this work, we demonstrate that a liquid gold-silicon alloy established in classical vapor-liquid-solid growth can deposit ordered and three-dimensional rings of isolated gold atoms over silicon nanowire sidewalls. We perform ab initio molecular dynamics simulation and unveil a surprising single atomic gold-catalyzed chemical etching of silicon...
December 8, 2017: Nature Communications
Concetta De Santi, Osman Absm Gani, Ronny Helland, Adele Williamson
The family 15 carbohydrate esterase (CE15) MZ0003, which derives from a marine Arctic metagenome, has a broader substrate scope than other members of this family. Here we report the crystal structure of MZ0003, which reveals that residues comprising the catalytic triad differ from previously-characterized fungal homologs, and resolves three large loop regions that are unique to this bacterial sub-clade. The catalytic triad of the bacterial CE15, which includes Asp 332 as its third member, closely resembles that of family 1 carbohydrate esterases (CE1), despite the overall lower structural similarity with members of this family...
December 8, 2017: Scientific Reports
Ermanila Dhana, Isis Ludwig-Portugall, Christian Kurts
Chronic kidney diseases can lead to kidney fibrosis, which can be considered a futile attempt of tissue healing to replaces functional kidney tissue with connective tissue, basically forming a scar. Chronic inflammation is a frequent cause of kidney fibrosis. Classical as well as recently discovered immune cell subsets and their molecular mediators have been intensively investigated for their contribution to kidney fibrosis and their potential as therapeutic targets. Here we review the current knowledge about the role of immune cells in crystal-induced renal fibrosis...
December 5, 2017: Matrix Biology: Journal of the International Society for Matrix Biology
Debra K Litzelman, Adrian Gardner, Robert M Einterz, Philip Owiti, Charity Wambui, Jordan C Huskins, Kathleen M Schmitt-Wendholt, Geren S Stone, Paul O Ayuo, Thomas S Inui, Rachel A Umoren
BACKGROUND: Globalization has increased the demand for international experiences in medical education. International experiences improve medical knowledge, clinical skills, and self-development; influence career objectives; and provide insights on ethical and societal issues. However, global health rotations can end up being no more than tourism if not structured to foster personal transformation and global citizenship. OBJECTIVE: We conducted a qualitative assessment of trainee-reported critical incidents to more deeply understand the impact of our global health experience on trainees...
May 2017: Annals of Global Health
Lingyuan Gao, Jaime Souto-Casares, James R Chelikowsky, Alexander A Demkov
Work function values measured at different surfaces of a metal are usually different. This raises an interesting question: What is the work function of a nano-size crystal, where differently oriented facets can be adjacent? Work functions of metallic nanocrystals are also of significant practical interest, especially in catalytic applications. Using real space pseudopotentials constructed within density functional theory, we compute the local work function of large aluminum and gold nanocrystals. We investigate how the local work function follows the change of the surface plane orientation around multifaceted nanocrystals, and we establish the importance of the orbital character near the Fermi level in determining work function differences between facets...
December 7, 2017: Journal of Chemical Physics
J Condoluci, S Janardan, A T Calvin, R Rugango, G Shu, C D Sherrill, K R Brown
We observe vibronic transitions in CaD+ between the 11Σ and 21Σ electronic states by resonance enhanced multiphoton photodissociation spectroscopy in a Coulomb crystal. The vibronic transitions are compared with previous measurements on CaH+. The result is a revised assignment of the CaH+ vibronic levels and a disagreement with multi-state-complete-active-space second-order perturbation theory theoretical calculations by approximately 700 cm-1. Updated high-level coupled-cluster calculations that include core-valence correlations reduce the disagreement between theory and experiment to 300 cm-1...
December 7, 2017: Journal of Chemical Physics
Ali Mirzaeinia, Farzaneh Feyzi, Seyed Majid Hashemianzadeh
Simple and accurate expressions are presented for the equation of state (EOS) and absolute Helmholtz free energy of a system composed of simple atomic particles interacting through the repulsive Lennard-Jones potential model in the fluid and solid phases. The introduced EOS has 17 and 22 coefficients for fluid and solid phases, respectively, which are regressed to the Monte Carlo (MC) simulation data over the reduced temperature range of 0.6≤T*≤6.0 and the packing fraction range of 0.1 ≤ η ≤ 0.72. The average absolute relative percent deviation in fitting the EOS parameters to the MC data is 0...
December 7, 2017: Journal of Chemical Physics
Lipeng Chen, Yang Zhao
Combining the multiple Davydov D2 Ansatz with the method of thermo-field dynamics, we study finite temperature dynamics of a Holstein polaron on a lattice. It has been demonstrated, using the hierarchy equations of motion method as a benchmark, that our approach provides an efficient, robust description of finite temperature dynamics of the Holstein polaron in the simultaneous presence of diagonal and off-diagonal exciton-phonon coupling. The method of thermo-field dynamics handles temperature effects in the Hilbert space with key numerical advantages over other treatments of finite-temperature dynamics based on quantum master equations in the Liouville space or wave function propagation with Monte Carlo importance sampling...
December 7, 2017: Journal of Chemical Physics
Zu-Wen Xie, Jhen-Hong Yang, Vishal Vashistha, Wei Lee, Kuo-Ping Chen
Designing color pixels using plasmonic nanostructures and metasurfaces has become a luring area of research in recent years. Here, we experimentally demonstrated the voltage tunability of a dynamic plasmonic color filter by using an aluminum grating integrated with the nematic liquid crystal (LC). Along with a typical substrate coated with rubbed polyimide film, the aluminum grating itself serves as a molecular alignment layer to form a twisted LC cell. This hybrid structure allows electrically controlled transmission color by applying the voltage...
November 27, 2017: Optics Express
Yiping Liu, Yunyun Dai, Qianchi Feng, Yuwei Shan, Lei Du, Yuyu Xia, Guang Lu, Fen Liu, Guiqiang Du, Chuanshan Tian, Shiwei Wu, Lei Shi, Jian Zi
Enhanced interactions of light with graphene on the surface of a lossless dielectric magnetic mirror (DMM) are studied theoretically and experimentally in the visible range, where the DMM is composed of truncated dielectric photonic crystals (PCs). The absorption of graphene on the DMM was enhanced by about 4-fold for the spectral range within the forbidden gap of PCs over a wide range of incidence angles for both transverse electric and transverse magnetic polarizations compared with that of free-standing graphene...
November 27, 2017: Optics Express
Ali Akbar, Muhammad Waleed Khalid, Muhammad Sabieh Anwar
Magnetic linear birefringence and dichroism are investigated for the paramagnetic terbium gallium garnet (TGG) single crystal in the temperature range 8-100 K. The reciprocal nature is confirmed for the linear birefringence. Furthermore a theoretical model is validated that describes the intermixing of linear and circular birefringence. The ellipticity and rotation of the polarization ellipse are investigated in the light of these measurements. These otherwise minuscule magnetically induced effects are amplified at cryogenic temperatures and are determined by a phase-sensitive technique based on the Fourier decomposition of detected signal intensities...
November 27, 2017: Optics Express
Austin Wilson, Hong Hua
State-of-the-art optical see-through head-mounted displays for augmented reality (AR) applications lack mutual occlusion capability, which refers to the ability to render correct light blocking relationship when merging digital and physical objects, such that the virtual views appear to be ghost-like and lack realistic appearance. In this paper, using off-the-shelf optical components, we present the design and prototype of an AR display which is capable of rendering per-pixel mutual occlusion. Our prototype utilizes a miniature organic light emitting display coupled with a liquid crystal on silicon type spatial light modulator to achieve an occlusion capable AR display offering a 30° diagonal field of view and an angular resolution of 1...
November 27, 2017: Optics Express
Xianhe Liu, Binh H Le, Steffi Y Woo, Songrui Zhao, Alexandre Pofelski, Gianluigi A Botton, Zetian Mi
Semiconductor light sources operating in the ultraviolet (UV)-C band (100-280 nm) are in demand for a broad range of applications but suffer from extremely low efficiency. AlGaN nanowire photonic crystals promise to break the efficiency bottleneck of deep UV photonics. We report, for the first time, site-controlled epitaxy of AlGaN nanowire arrays with Al incorporation controllably varied across nearly the entire compositional range. It is also observed that an Al-rich AlGaN shell structure is spontaneously formed, significantly suppressing nonradiative surface recombination...
November 27, 2017: Optics Express
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