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Confined Spaces

Bing An, Jingzheng Zhang, Kang Cheng, Pengfei Ji, Cheng Wang, Wenbin Lin
The interfaces of Cu/ZnO and Cu/ZrO2 play vital roles in the hydrogenation of CO2 to methanol by these composite catalysts. Surface structural reorganization and particle growth during catalysis deleteriously reduce these active interfaces, diminishing both catalytic activities and MeOH selectivities. Here we report the use of pre-assembled bpy and Zr6(μ3-O)4(μ3-OH)4 sites in UiO-bpy metal-organic frameworks (MOFs) to anchor ultrasmall Cu/ZnOx nanoparticles, thus preventing the agglomeration of Cu NPs and phase separation between Cu and ZnOx in MOF cavity-confined Cu/ZnOx nanoparticles...
February 17, 2017: Journal of the American Chemical Society
Stefania Monterisi, Manuela Zaccolo
3'-5'-Cyclic adenosine monophosphate/protein kinase A (cAMP/PKA) signalling is activated by different extracellular stimuli and mediates many diverse processes within the same cell. It is now well established that in order to translate into the appropriate cellular function multiple extracellular inputs, which may act simultaneously on the same cell, the cAMP/PKA signalling pathway is compartmentalised. Multimolecular complexes are organised at specific subcellular sites to generate spatially confined signalosomes, which include effectors, modulators and targets of the pathway...
February 8, 2017: Biochemical Society Transactions
X Cui, Y Hartanto, H Zhang
Three-dimensional multicellular spheroids (MCSs) have a complex architectural structure, dynamic cell-cell/cell-matrix interactions and bio-mimicking in vivo microenvironment. As a fundamental building block for tissue reconstruction, MCSs have emerged as a powerful tool to narrow down the gap between the in vitro and in vivo model. In this review paper, we discussed the structure and biology of MCSs and detailed fabricating methods. Among these methods, the approach in microfluidics with hydrogel support for MCS formation is promising because it allows essential cell-cell/cell-matrix interactions in a confined space...
February 2017: Journal of the Royal Society, Interface
Jonathan K George, Volker J Sorger
Spatial division multiplexing utilizes the directionality of the light's propagating k-vector to separate it into distinct spatial directions. Here, we show that the anisotropy of orthogonal spatial solitons propagating in a single graphene monolayer results in phase-based multiplexing. We use the self-confinement properties of spatial solitons to increase the usable density of states (DOS) of this switching system. Furthermore, we show that crossing two orthogonal solitons exhibits a low (0.035 dB) mutual disturbance from another enabling independent k-vector switching...
February 15, 2017: Optics Letters
Shoya Yasuda, Masayuki Hayakawa, Hiroaki Onoe, Masahiro Takinoue
This paper reports a twisting microfluidic method utilising a centrifuge-based fluid extruding system in a planetary centrifuge which simultaneously generates an orbital rotation and an axial spin. In this method, fluid extrusion from a micro-scale capillary to an 'open-space' solution or air enables release of the fluid from the capillary-based microchannel, which physically means that there is a release of fluids from a confined low-Reynolds-number environment to an open non-low-Reynolds-number environment...
February 13, 2017: Soft Matter
Andreas Schulze, Roger Loo, Paul Ryan, Matthew Wormington, Paola Favia, Liesbeth Witters, Nadine Collaert, Hugo Bender, Wilfried Vandervorst, Matty Caymax
The performance of heterogeneous 3D transistor structures critically depends on the composition and strain state of the buffer, channel and source/drain regions. In this paper we used an in-line high resolution X-ray diffraction (HRXRD) tool to study in detail the composition and strain in selectively grown SiGe/Ge fin structures with widths down to 20nm. For this purpose we arranged fins of identical dimensions into larger arrays which were then analyzed using an X-ray beam several tens of micrometer in size...
February 10, 2017: Nanotechnology
Yongfang Yang, Li Hua, Yue Zhang, Hefang Wang, Lidong Xu, Hanying Zhao
The hybrid nanocrystals---PVBA-b-PS/ZIF-8 were prepared by the growth of ZIF-8 on the surface of the self-assembled structures from poly(p-vinylbenzoic acid)-block-polystyrene. Two different morphologies---micelles and vesicles were obtained in selective solvents owing to the different ratios of PVBA to PS blocks. The structure and morphology of the PVBA-b-PS/ZIF-8 composites were characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray diffraction, transmission electron microscopy and scanning electron microscopy...
February 8, 2017: Chemistry, An Asian Journal
Di Yuan, Fang Lin, Limei Wang, Danyang Liu, Junzhong Yang, Yi Xiao
We investigate the generalized Kuramoto model of globally coupled oscillators with inertia, in which oscillators with positive coupling strength are conformists and oscillators with negative coupling strength are contrarians. We consider the correlation between the coupling strengths of oscillators and the distributions of natural frequencies. Two different types of correlations are studied. It is shown that the model supports multistable synchronized states such as different types of travelling wave states, π state and another type of nonstationary state: an oscillating π state...
February 8, 2017: Scientific Reports
C Strewe, R Zeller, M Feuerecker, M Hoerl, I Kumprej, A Crispin, B Johannes, T Debevec, I Mekjavic, G Schelling, A Choukèr
Immobilization and hypoxemia are conditions often seen in patients suffering from severe heart insufficiency or primary pulmonary diseases (e.g. fibrosis, emphysema). In future planned long-duration and exploration class space missions (including habitats on the moon and Mars), healthy individuals will encounter such a combination of reduced physical activity and oxygen tension by way of technical reasons and the reduced gravitational forces. These overall unconventional extraterrestrial conditions can result in yet unknown consequences for the regulation of stress-permissive, psycho-neuroendocrine responses, which warrant appropriate measures in order to mitigate foreseeable risks...
February 6, 2017: Stress: the International Journal on the Biology of Stress
Julian A Lloyd, Soon Hock Ng, Amelia C Y Liu, Ye Zhu, Wei Chao, Toon Coenen, Joanne Etheridge, Daniel E Gómez, Udo Bach
Asymmetric nanoparticle trimers composed of particles with increasing diameter act as "plasmonic lenses" and have been predicted to exhibit ultrahigh confinement of electromagnetic energy in the space between the two smallest particles. Here we present an electrostatic self-assembly approach for creating gold nanoparticle trimers with an assembly yield of over 60%. We demonstrate that the trimer assembly leads to characteristic red-shifts and show the localization of the relevant plasmon modes by means of cathodoluminescence and electron energy loss spectroscopy...
February 13, 2017: ACS Nano
Victor Malgras, Joel Henzie, Toshiaki Takei, Yusuke Yamauchi
We successfully synthesized hybrid methylammonium lead halide nanocrystals confined in a gyroidal mesoporous silica template. The nanocrystals adopted the same crystal structure as their bulk perovskite counterparts, highlighting the ability to control the bandgap by tuning the pore-size of the template. Besides providing more accessible spaces for the materials to diffuse within the channels, the 3D mesh of the gyroidal template should also allow easier escape of the solvent and pinning of the particles at different points, thus promoting the formation of isolated nanoparticles over larger structures (e...
February 6, 2017: Chemical Communications: Chem Comm
Mark A W Hornsby, Susan D Healy, T Andrew Hurly
Animals use cues from their environment to orient in space and to navigate their surroundings. Geometry is a cue whose informational content may originate from the metric properties of a given environment, and its use has been demonstrated in the laboratory in nearly every species of animal tested. However, it is not clear whether geometric information, used by animals typically tested in small, rectangular boxes, is directly relevant to animals in their natural environment. Here we present the first data that confirm the use of geometric cues by a free-living animal in the wild...
February 1, 2017: Behavioural Processes
Pauline Roux, Alicia Guillien, Thibaud Soumagne, Ophélie Ritter, Jean-Jacques Laplante, Cécile Travers, Jean-Charles Dalphin, Gérard Peiffer, Lucie Laurent, Bruno Degano
BACKGROUND: Farmers are exposed to multiple air contaminants that may interact with tobacco smoking in the development of respiratory diseases. Farmers are currently considered to smoke less than non-farmers, but precise data in different categories of age and farming activities are lacking. METHODS: Smoking habits were studied in a cross-sectional study involving 4105 farmers and 996 non-farming controls aged 40-74 years in 9 French departments between October 2012 and May 2013...
February 4, 2017: BMC Public Health
Eric Aguado, Guillaume Mabilleau, Eric Goyenvalle, Daniel Chappard
Disuse induces a rapid bone loss in humans and animals; hypodynamia/sedentarity is now recognized as a risk factor for osteoporosis. Hypodynamia also decreases bone mass but its effects are largely unknown and only few animal models have been described. Hypodynamic chicken is recognized as a suitable model of bone loss but the effects on the quality have not been fully explored. We have used ten chickens bred in a large enclosure (FREE group); ten others were confined in small cages with little space to move around (HYPO group)...
February 3, 2017: Calcified Tissue International
LiYa Wang, HengAn Wu, FengChao Wang
Nanopumps conducting fluids through nanochannels have attracted considerable interest for their potential applications in nanofiltration, water desalination and drug delivery. Here, we demonstrate by molecular dynamics (MD) simulations that a nano screw pump is designed with helical nanowires embedded in a nanochannel, which can be used to drive unidirectional water flow. Such helical nanowires have been successfully synthesized in many experiments. By investigating the water transport mechanism through nano screw pumps with different configuration parameters, three transport modes were observed: cluster-by-cluster, pseudo-continuous, and linear-continuous, in which the water flux increases linearly with the rotating speed...
February 3, 2017: Scientific Reports
Xiaogang Wu, Ningning Wang, Zhaowei Wang, Weilun Yu, Yanqin Wang, Yuan Guo, Weiyi Chen
BACKGROUND: Mechanical load-induced intraosseous pressure gradients may result in some fluid stimuli effects, such as fluid flow and fluid shear stress (FSS), which may enable bone cells to detect external mechanical signals. Interstitial bone fluid flow is known to occur in lacunar-canalicular porosity (PLC). METHODS: In order to characterize lacunar-canalicular fluid flow behavior, a hierarchical osteon system is developed. The osteon is modeled as a poroelastic annular cylinder with two types of impermeable boundary cases considered on its outer wall: one is elastic restrained (Case I), whereas the other is displacement confined (Case II)...
December 28, 2016: Biomedical Engineering Online
Keng-Ku Liu, Qisheng Jiang, Sirimuvva Tadepalli, Ramesh Raliya, Pratim Biswas, Rajesh R Naik, Srikanth Singamaneni
Solar steam generation is a highly promising technology for harvesting solar energy, desalination and water purification. We introduce a novel bilayered structure comprised of wood and graphene oxide (GO) for highly efficient solar steam generation. The GO layer deposited on the microporous wood provides broad optical absorption and high photothermal conversion resulting in rapid increase in the temperature at the liquid surface. On the other hand, wood serves as a thermal insulator to confine the photothermal heat to the evaporative surface and to facilitate the efficient transport of water from the bulk to the photothermally-active space...
February 2, 2017: ACS Applied Materials & Interfaces
Martin Kolev, Claudia Kemper
The complement system is an evolutionary old and crucial component of innate immunity, which is key to the detection and removal of invading pathogens. It was initially discovered as a liver-derived sentinel system circulating in serum, the lymph, and interstitial fluids that mediate the opsonization and lytic killing of bacteria, fungi, and viruses and the initiation of the general inflammatory responses. Although work performed specifically in the last five decades identified complement also as a critical instructor of adaptive immunity-indicating that complement's function is likely broader than initially anticipated-the dominant opinion among researchers and clinicians was that the key complement functions were in principle defined...
2017: Frontiers in Immunology
P F Knapp, C Ball, K Austin, S B Hansen, M D Kernaghan, P W Lake, D J Ampleford, L A McPherson, D Sandoval, P Gard, M Wu, C Bourdon, G A Rochau, R D McBride, D B Sinars
We describe the design and function of a new time and space resolved x-ray spectrometer for use in Z-pinch inertial confinement fusion and radiation source development experiments. The spectrometer is designed to measure x-rays in the range of 0.5-1.5 Å (8-25 keV) with a spectral resolution λ/Δλ ∼ 400. The purpose of this spectrometer is to measure the time- and one-dimensional space-dependent electron temperature and density during stagnation. These relatively high photon energies are required to escape the dense plasma created at stagnation and to obtain sensitivity to electron temperatures ≳3 keV...
January 2017: Review of Scientific Instruments
S Y Mashayak, N R Aluru
Water is a highly polar solvent. As a result, electrostatic interactions of interfacial water molecules play a dominant role in determining the distribution of ions in electric double layers (EDLs). Near a surface, an inhomogeneous and anisotropic arrangement of water molecules gives rise to pronounced variations in the electrostatic and hydration energies of ions. Therefore, a detailed description of the structural and dielectric properties of water is important to study EDLs. However, most theoretical models ignore the molecular effects of water and treat water as a background continuum with a uniform dielectric permittivity...
January 28, 2017: Journal of Chemical Physics
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