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Dandan Ju, Feng Song, Yingdong Han, Wenjing Cui, Aihua Zhou, Shujing Liu, Xueqin Wang, Ming Feng, Chengguo Ming
We synthesized the uniform core-shell microstructured compounds with hexagonal phase NaYF₄:Er/Yb microrods as the core and hexagonal phase NaLnF₄ (NaYbF₄, NaLuF₄:Yb/Tm, NaYF₄:Yb/Er, NaYF₄:Eu) as the shell based on the hydrothermal reaction. These microscale core-shell structures provided a platform for the spatially confining optical process while possessing high luminescence efficiency. The thickness of the shell could be controlled by adjusting the amounts of shell precursor, which significantly affected the intensity of the shell dopant ions emission and the emission color of core-shell upconversion luminescence (UCL)...
December 14, 2017: Nanomaterials
Kellie Adamson, Elaine Spain, Una Prendergast, Niamh Moran, Robert J Forster, Tia E Keyes
Human blood platelets and SK-N-AS neuroblastoma cancer cell capture at spontaneously adsorbed monolayers of fibrinogen binding motifs GRGDS (generic integrin adhesion), HHLGGAKQAGDV (exclusive to platelet integrin αIIbβ3) or octanethiol (adhesion inhibitor) at planar gold and ordered 1.6 micron diameter spherical cap gold cavity arrays was compared. In all cases, RGD promoted capture while alkanethiol monolayers inhibited adhesion. Conversely only platelets adhered to AGD modified surfaces, indicating the AGD motif is recognized preferentially by the platelet specific integrin, αIIbβ3...
December 14, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
En-Li Lin, Wei-Lun Hsu, Yeo-Wan Chiang
In theory, gyroid photonic crystals in butterfly wings exhibit advanced optical properties as a result of their highly interconnected microstructures. Because of the difficulties in synthesizing artificial gyroid materials having periodicity corresponding to visible wavelengths, human-made visible gyroid photonic crystals are still unachievable by self-assembly. In this study, we develop a physical approach-trapping of structural coloration (TOSC)-through which the visible structural coloration of an expanded gyroid lattice in a solvated state can be preserved in the solid state, thereby allowing the fabrication of visible-wavelength gyroid photonic crystals...
December 14, 2017: ACS Nano
Lei Shao, John R Lawall, Jason J Gorman
Ultrafast pulsed laser interferometry (PLI) can measure picometer displacements at sub-nanosecond time scales, such as acoustic waves and vibrations in microstructures. In this Letter, the effects of pulse characteristics on the accuracy of PLI are investigated through measurements and modeling. The results show that the effective wavelength of PLI, λeff, varies significantly as a function of overlap between the interfering pulses due to pulse asymmetry and nonlinear chirp. This variation presents a serious limitation on the accuracy of PLI if unaddressed...
December 15, 2017: Optics Letters
Curtis L Johnson, Eva H Telzer
Magnetic resonance elastography (MRE) is a quantitative imaging technique for noninvasively characterizing tissue mechanical properties, and has recently emerged as a valuable tool for neuroimaging. The measured mechanical properties reflect the microstructural composition and organization of neural tissue, and have shown significant effects in many neurological conditions and normal, healthy aging, and evidence has emerged supporting novel relationships between mechanical structure and cognitive function. The sensitivity of MRE to brain structure, function, and health make it an ideal technique for studying the developing brain; however, brain MRE studies on children and adolescents have only just begun...
September 1, 2017: Developmental Cognitive Neuroscience
Geerada Kaewjumpol, Maria J Oruna-Concha, Keshavan Niranjan, Supawan Thawornchinsombut
BACKGROUND: This research employed mild-subcritical alkaline water extraction (SAW) technique to overcome the difficulty of active compounds extractability from an industrially defatted rice bran (IDRB). Mild-SAW (pH 9.5, 130 °C, 120 min) treatment, followed by enzymatic hydrolysis (Protease G6) were applied to produce rice bran hydrolysate (RBH). Response surface methodology was used to identify proteolysis conditions for maximizing protein content and ABTS radical scavenging activity (ABTS-RSA)...
December 14, 2017: Journal of the Science of Food and Agriculture
Sohae Chung, Els Fieremans, Xiuyuan Wang, Nuri E Kucukboyaci, Charles J Morton, James S Babb, Prin Amorapanth, Farng-Yang Foo, Dmitry S Novikov, Steven R Flanagan, Joseph F Rath, Yvonne W Lui
We seek to elucidate the underlying pathophysiology of injury sustained after mild traumatic brain injury (MTBI) using multi-shell diffusion MRI, deriving compartment-specific WM tract integrity (WMTI) metrics. WMTI allows a more biophysical interpretation of WM changes by describing microstructural characteristics in both intra- and extra-axonal environments. Thirty-two patients with MTBI within 30 days of injury and twenty-one age- and sex-matched controls were imaged on a 3T MR scanner. Multi-shell diffusion acquisition was performed with 5 b-values (250 - 2500 s/mm<sup>2</sup>) along 6 - 60 diffusion encoding directions...
December 14, 2017: Journal of Neurotrauma
Haneun Kim, Seung-Wook Lee, Hyungmok Joh, Mingi Seong, Woo Seok Lee, Min Su Kang, Jun Beom Pyo, Soong Ju Oh
With the increase of interest in wearable tactile pressure sensors for e-skin, researches to make nanostructures to achieve high sensitivity have been actively conducted. However, limitations such as complex fabrication processes using expensive equipment still exist. Herein, simple lithography-free techniques to develop pyramid-like metal/insulator hybrid nanostructures utilizing nanocrystals (NCs) are demonstrated. Ligand-exchanged and unexchanged silver NC thin films are used as metallic and insulating components, respectively...
December 14, 2017: ACS Applied Materials & Interfaces
Elisabeth Rieger, Jan Blankenburg, Eduard Grune, Manfred Wagner, Katharin Landfester, Frederik Roman Wurm
An ideal random anionic copolymerization is forced to gradient structures by physical separation of two monomers in emulsion compartments. One monomer (M) is preferably soluble in the droplets, while the other one (D) prefers the continuous phase of a DMSO-in-cyclohexane emulsion. The living anionic copolymerization of two activated aziridines is thus confined to the DMSO compartments as polymerization occurs selectively in the droplets. Dilution of the continuous phase adjusts the local concentration of monomer D in the droplets and thus the gradient of the resulting copolymer...
December 13, 2017: Angewandte Chemie
Shaymaa E Elsaka
PURPOSE: To evaluate the optical and mechanical properties of newly introduced monolithic multilayer zirconia with two types of monolithic zirconia. MATERIALS AND METHODS: Three brands of monolithic zirconia were used in this study: Ceramill Zolid FX Multilayer (CZF), Prettau Anterior (PA), and Zenostar T (ZT). Translucency parameter (TP), contrast ratio (CR), flexural strength, fracture toughness, hardness, brittleness index, and microstructures were assessed. Data were analyzed using one-way ANOVA and Tukey's test...
December 14, 2017: Journal of Prosthodontics: Official Journal of the American College of Prosthodontists
Jae-Kang Kim, Michael Varenberg
To date, a handful of different gecko-like adhesives inspired by spatula-shaped attachment hairs have been suggested based on wedge and flap geometry of contact elements. However, while these surface designs have been shown to have directionality in adhesion, high friction, long lifetime and the ability to work in vacuum, an experimental verification of the very basic concept of the pulling angle effect has not yet been reported. To close this gap, here we use wall-shaped adhesive microstructures of three different flap heights to systematically study the effect of pulling angle on the normal and tangential components of the pull-off force tested at different preliminary tangential displacements...
December 2017: Journal of the Royal Society, Interface
Zulmira A S Guimarães, Renato A Damatta, Renan S Guimarães, Marcello Filgueira
With the aim of introducing permanent prostheses with main properties equivalent to cortical human bone, Ti-diamond composites were processed through powder metallurgy. Grade 1 titanium and mixtures of Ti powder with 2%, 5% and 10 wt% diamond were compacted at 100MPa, and then sintered at 1250°C/2hr/10-6mbar. Sintered samples were studied in the point of view of their microstructures, structures, yield strength and elastic modulus. The results showed that the best addition of diamonds was 2 wt%, which led to a uniform porosity, yield strength of 370MPa and elastic modulus of 13...
December 11, 2017: Anais da Academia Brasileira de Ciências
Yingfei Li, Na Tian, Xiaodong Fan, Caiyin You, Wenli Pei, Zhenxiang Cheng
Low coercivity is the main disadvantage of RE-Fe-B permanent magnets containing highly abundant rare earths (RE: La, Ce) from the application point of view, even though they exhibit many cost and resource advantages. In this work, an industrial mixed rare earth alloy (RE100 = La30.6Ce50.2Pr6.4Nd12.8) with a high amount of the more abundant elements was adopted to fabricate RE-Fe-B permanent magnets by means of mechanical alloying accompanied by post-annealing. A synergetic effect towards enhancing the coercivity was observed after co-doping with Dy2O3 and Ca, with the coercivity increasing from 2...
December 13, 2017: Nanoscale Research Letters
Jinxuan Bai, Qingshun Bai, Zhen Tong
This article presents an experimental investigation on ductile-mode micro-milling of monocrystalline silicon using polycrystalline diamond (PCD) end mills. Experimental results indicate that the irregular fluctuation of cutting force always induces machined surface failure, even in ductile mode. The internal mechanism has not been investigated so far. The multiscale discrete dislocation plasticity framework was used to predict the dislocation structure and strain evolution under the discontinuous cutting process...
December 13, 2017: Materials
Xiaoxiao Huang, Shuchen Sun, Ganfeng Tu, Shuaidan Lu, Kuanhe Li, Xiaoping Zhu
Nanocrystalline titanium diboride (TiB₂) ceramics films were prepared on a high purity graphite substrate via chemical vapor deposition (CVD). The substrate was synthesized by a gas mixture of TiCl₄, BCl₃, and H₂ under 1000 °C and 10 Pa. Properties and microstructures of TiB₂ films were also examined. The as-deposited TiB₂ films had a nano-sized grain structure and the grain size was around 60 nm, which was determined by X-ray diffraction, field emission scanning electron microscopy, and transmission electron microscopy...
December 13, 2017: Materials
Caixia Li, Zhucong Xi, Dexiang Guo, Xiangju Chen, Longwei Yin
Despite great progress in lithium-sulfur batteries (LSBs), great obstacles still exist to achieve high loading content of sulfur and avoid the loss of active materials due to the dissolution of the intermediate polysulfide products in the electrolyte. Relationships between the intrinsic properties of nanostructured hosts and electrochemical performance of LSBs, especially, the chemical interaction effects on immobilizing polysulfides for LSB cathodes, are discussed in this Review. Moreover, the principle of rational microstructure design for LSB cathode materials with strong chemical interaction adsorbent effects on polysulfides, such as metallic compounds, metal particles, organic polymers, and heteroatom-doped carbon, is mainly described...
December 13, 2017: Small
Shan-Shan Chu, Liang-Ping Zha, Hai-Yan Duan, Tao Xu, Hua-Sheng Peng
The growth years of medicinal materials are closely related to their quality, and "Herb-chronology" has been used to determine the growth years of perennial dicotyledonous plants in recent years. On the basis of conventional paraffin section and freehand section, the anatomical study on roots of seven Sect. Paeonia species and main roots of cultivated Paeonia lactiflora was conducted in this paper. The results showed that, there existed some differences in microstructure of the seven species such as P. lactiflora, P...
October 2017: Zhongguo Zhong Yao za Zhi, Zhongguo Zhongyao Zazhi, China Journal of Chinese Materia Medica
John J Bowen, Mark A Rose, Abhiteja Konda, Stephen A Morin
This work describes the fabrication of numerous hydrogel microstructures, μ-gels, via a process called "surface molding"-chemically patterned elastomeric assembly substrates were used to organize and manipulate the geometry of liquid prepolymer microdroplets, which, following photo-initiated crosslinking, maintained the desired morphology. By adjusting the state of strain during the crosslinking process, a continua of structures could be created using one pattern. These arrays of μ-gels have stimuli-responsive properties that are directly applicable to actuation where the basis shape and array geometry of the μ-gels can be used to rationally generate microactuators with programmed motions...
December 12, 2017: Angewandte Chemie
Akinjide R Akintunde, Kristin S Miller
Tendon injuries are common to all ages. Injured tendons typically do not recover full functionality. The amount and organization of tendon constituents dictate their mechanical properties. The impact of changes in these constituents during (patho)physiologic processes (e.g., aging and healing) are not fully understood. Toward this end, microstructurally motivated strain energy functions (SEFs) offer insight into underlying mechanisms of age-dependent healing. Several SEFs have been adapted for tendon; however, most are phenomenological...
December 12, 2017: Biomechanics and Modeling in Mechanobiology
Christiana E Udoh, João T Cabral, Valeria Garbin
The precise spatiotemporal delivery of nanoparticles from polymeric capsules is required for applications ranging from medicine to materials science. These capsules derive key performance aspects from their overall shape and dimensions, porosity, and internal microstructure. To this effect, microfluidics provide an exceptional platform for emulsification and subsequent capsule formation. However, facile and robust approaches for nanocomposite capsule fabrication, exhibiting triggered nanoparticle release, remain elusive because of the complex coupling of polymer-nanoparticle phase behavior, diffusion, phase inversion, and directional solidification...
December 2017: Science Advances
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