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Confined Spaces

R Jayaprakash, F G Kalaitzakis, G Christmann, K Tsagaraki, M Hocevar, B Gayral, E Monroy, N T Pelekanos
Polariton lasers are coherent light sources based on the condensation of exciton-polaritons in semiconductor microcavities, which occurs either in the kinetic or thermodynamic (Bose-Einstein) regime. Besides their fundamental interest, polariton lasers have the potential of extremely low operating thresholds. Here, we demonstrate ultra-low threshold polariton lasing at room temperature, using an all-dielectric, GaN membrane-based microcavity, with a spontaneously-formed zero-dimensional trap. The microcavity is fabricated using an innovative method, which involves photo-electrochemical etching of an InGaN sacrificial layer and allows for the incorporation of optimally-grown GaN active quantum wells inside a cavity with atomically-smooth surfaces...
July 17, 2017: Scientific Reports
András Szabó, Roeland M H Merks
Cancer is a disease of cellular regulation, often initiated by genetic mutation within cells, and leading to a heterogeneous cell population within tissues. In the competition for nutrients and growth space within the tumors the phenotype of each cell determines its success. Selection in this process is imposed by both the microenvironment (neighboring cells, extracellular matrix, and diffusing substances), and the whole of the organism through for example the blood supply. In this view, the development of tumor cells is in close interaction with their increasingly changing environment: the more cells can change, the more their environment will change...
July 17, 2017: PLoS Computational Biology
F Lingua, V Penna
A bosonic gas formed by two interacting species trapped in a double-well potential features macroscopic localization effects when the interspecies interaction becomes sufficiently strong. A repulsive interaction spatially separates the species into different wells while an attractive interaction confines both species in the same well. We perform a fully analytic study of the transitions from the weak- to the strong-interaction regime by exploiting the semiclassical method in which boson populations are represented in terms of continuous variables...
June 2017: Physical Review. E
Vasileios Kokkinos, Andreas M Koupparis, Michalis Koutroumanidis, George K Kostopoulos
OBJECTIVE: This work investigates the spatial distribution in time of generalized ictal spikes in the typical absences of childhood absence epilepsy (CAE). METHODS: We studied twelve children with CAE, who had more than two typical absences during their routine video-EEG. Seizures were identified, and ictal spikes were marked over the maximum electronegative peak, clustered, waveform-averaged and spatiotemporaly analyzed in 2D electrode space. RESULTS: Consistency of spatiotemporal patterns of ictal spikes was high between the absences of the same child, but low between children...
June 17, 2017: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
Ming-Yue Zhang, Xiang Li, Xiao-Hui Zhang, Hong-Gui Liu, Jian-Hong Li, Jun Bao
The aim of this study was to evaluate the effects of space restriction stress on the stereotypic behavioral and physiological responses of different parity sows, and it is necessary to understand such effects due to space restriction to improve the welfare of the sows in confined conditions. We selected fifty pregnant sows (Large White) at primiparity and first to fifth parity in a confined farm with the same body condition and due date (3±1.5days). Behavioral observations and physiological analysis were carried out during spatial confinement throughout pregnancy...
July 11, 2017: Physiology & Behavior
Jianing Guo, Yang Li, Yuanhui Cheng, Liming Dai, Zhonghua Xiang
The output energy capacity of green electrochemical devices, e.g., fuel cells, depends strongly on the sluggish oxygen reduction reaction (ORR), which requires catalysts. One of the desired features for highly efficient ORR electrocatalytic materials is the rich of well-defined activate sites. Herein, we developed a facile approach to prepare highly efficient non-precious metal and nitrogen-doped carbon-based ORR catalysts basing on covalent organic polymers (COPs) synthesized in-situ in the nanoconfined space of highly order metal organic frameworks (MOFs)...
July 13, 2017: ACS Nano
Sugata P Tan, Mohammad Piri
Many fluid mixtures exhibit retrograde behavior, including those that define natural gases. While the behavior is well understood for mixtures in bulk, it is not so in nanosize porous space that dominates shale formations in unconventional reservoirs. The lack of experimental data creates the need for modeling works to make estimates as good as possible due to immediate needs in gas recovery. However, such efforts have been straying without firm guidance from systematic studies over what we have known so far...
July 12, 2017: Physical Chemistry Chemical Physics: PCCP
Victor Segura-Ibarra, Francisca E Cara, Suhong Wu, David A Iruegas-Nunez, Sufen Wang, Mauro Ferrari, Arturas Ziemys, Miguel Valderrabano, Elvin Blanco
Pharmacological therapies for cardiovascular diseases are limited by short-term pharmacokinetics and extra-cardiac adverse effects. Improving delivery selectivity specifically to the heart, wherein therapeutic drug levels can be maintained over time, is highly desirable. Nanoparticle (NP)-based pericardial drug delivery could provide a strategy to concentrate therapeutics within a unique, cardiac-restricted compartment to allow sustained drug penetration into the myocardium. Our objective was to explore the kinetics of myocardial penetration and retention after pericardial NP drug delivery...
July 9, 2017: Journal of Controlled Release: Official Journal of the Controlled Release Society
Adarshi Welegedara, Yin Yang, Michael Lee, James Swarbrick, Thomas Huber, Bim Graham, Daniella Goldfarb, Gottfried Otting
Double-arm cyclen-based Gd3+ tags are shown to produce accurate nanometer scale Gd3+-Gd3+ distance measurements in double electron-electron resonance (DEER) experiments by confining the space accessible to the metal ion. The results show excellent agreement with predictions both for the maximum and width of the measured distance distributions. For distance measurements in proteins, the tags can be attached to two cysteine residues located in positions i and i+4, or i and i+8, of an α-helix. In the latter case, an additional mutation introducing an aspartic acid at position i+4 achieves particularly narrow distribution widths...
July 9, 2017: Chemistry: a European Journal
Sanaz Sadegh, Jenny L Higgins, Patrick C Mannion, Michael M Tamkun, Diego Krapf
A broad range of membrane proteins display anomalous diffusion on the cell surface. Different methods provide evidence for obstructed subdiffusion and diffusion on a fractal space, but the underlying structure inducing anomalous diffusion has never been visualized because of experimental challenges. We addressed this problem by imaging the cortical actin at high resolution while simultaneously tracking individual membrane proteins in live mammalian cells. Our data confirm that actin introduces barriers leading to compartmentalization of the plasma membrane and that membrane proteins are transiently confined within actin fences...
January 2017: Physical Review. X
Francisco Marques, Alvaro Meseguer, Fernando Mellibovsky, Patrick D Weidman
Extensional self-similar flows in a channel are explored numerically for arbitrary stretching-shrinking rates of the confining parallel walls. The present analysis embraces time integrations, and continuations of steady and periodic solutions unfolded in the parameter space. Previous studies focused on the analysis of branches of steady solutions for particular stretching-shrinking rates, although recent studies focused also on the dynamical aspects of the problems. We have adopted a dynamical systems perspective, analysing the instabilities and bifurcations the base state undergoes when increasing the Reynolds number...
June 2017: Proceedings. Mathematical, Physical, and Engineering Sciences
Mary Williard Elting, Manu Prakash, Dylan B Udy, Sophie Dumont
Active forces generated at kinetochores move chromosomes, and the dynamic spindle must robustly anchor kinetochore fibers (k-fibers) to bear this load. The mammalian spindle bears the load of chromosome movement far from poles, but we do not know where and how-physically and molecularly-this load distributes across the spindle. In part, this is because probing spindle mechanics in live cells is difficult. Yet answering this question is key to understanding how the spindle generates and responds to force and performs its diverse mechanical functions...
June 29, 2017: Current Biology: CB
Gianguglielmo Zehender, Carla Veo, Erika Ebranati, Valentina Carta, Francesca Rovida, Elena Percivalle, Ana Moreno, Davide Lelli, Mattia Calzolari, Antonio Lavazza, Chiara Chiapponi, Laura Baioni, Gioia Capelli, Silvia Ravagnan, Graziana Da Rold, Enrico Lavezzo, Giorgio Palù, Fausto Baldanti, Luisa Barzon, Massimo Galli
West Nile virus lineage 2 (WNV-2) was mainly confined to sub-Saharan Africa until the early 2000s, when it was identified for the first time in Central Europe causing outbreaks of human and animal infection. The aim of this study was to reconstruct the origin and dispersion of WNV-2 in Central Europe and Italy on a phylodynamic and phylogeographical basis. To this aim, discrete and continuous space phylogeographical models were applied to a total of 33 newly characterised full-length viral genomes obtained from mosquitoes, birds and humans in Northern Italy in the years 2013-2015 aligned with 64 complete sequences isolated mainly in Europe...
2017: PloS One
Anna V Maltsev, Victor A Maltsev, Michael D Stern
Intracellular Ca signals represent a universal mechanism of cell function. Messages carried by Ca are local, rapid, and powerful enough to be delivered over the thermal noise. A higher signal-to-noise ratio is achieved by a cooperative action of Ca release channels such as IP3 receptors or ryanodine receptors arranged in clusters (release units) containing a few to several hundred release channels. The channels synchronize their openings via Ca-induced Ca release, generating high-amplitude local Ca signals known as puffs in neurons and sparks in muscle cells...
July 3, 2017: Proceedings of the National Academy of Sciences of the United States of America
Federico Giberti, Ali A Hassanali
The magnitude of the pH of the surface of water continues to be a contentious topic in the physical chemistry of aqueous interfaces. Recent theoretical studies have shown little or no preference for the proton to be at the surface compared to the bulk. Using ab initio molecular dynamics simulations, we revisit the propensity of the excess proton for the air-water interface with a particular focus on the role of instantaneous liquid interfaces. We find a more pronounced presence for the proton to be at the air-water interface...
June 28, 2017: Journal of Chemical Physics
Rasha G AbdulHalim, Prashant M Bhatt, Youssef Belmabkhout, Aleksander Shkurenko, Karim Adil, Leonard J Barbour, Mohamed Eddaoudi
Conventional adsorbents, namely zeolites and silica gel, are often used to control humidity by adsorbing water; however, adsorbents capable of dual functionality of humidification and dehumidification, offering the desired control of the moisture level at room temperature, has yet to be explored. Here we report Y-shp-MOF-5, a hybrid microporous highly-connected Rare-Earth based metal-organic framework (MOF), with dual functionality for moisture control within the recommended range of relative humidity (45% to 65% RH) set by the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE)...
June 29, 2017: Journal of the American Chemical Society
Yuzhang Liang, Si Zhang, Xun Cao, Yanqing Lu, Ting Xu
Plasmonic spectrum filtering devices based on metallic nanostructures have attracted wide attention due to their good reliability, ease of fabrication, and wideband tunability. However, the presence of thick substrate significantly limits the structure's longitudinal size for further optoelectronic integration and reduces the devices' performance. Here we propose and demonstrate an ultra-thin plasmonic bandpass filter based on free-standing periodic metal-dielectric-metal stack geometry working in the near-infrared wavelength range...
June 28, 2017: Scientific Reports
Vijith Kumar, Tullio Pilati, Silvio Quici, Michele Remo Chierotti, Carlo Nervi, Roberto Gobetto, Giuseppe Resnati
Some experimental observations and theoretical calculations are reported on the structural features, in the solid, of crypt-111∙HI 1 and the three-component co-crystals that it forms with ,-diiodoperfluoroalkanes 2a-d. X-ray analyses indicate that, in all the five systems, the caged proton is, at low temperature, covalently bonded to a single nitrogen atom and is involved in a net of intramolecular hydrogen bonds. In contrast, 15N SSNMR at room temperature points to the magnetic equivalency of the two N atoms of crypt-111 in both 1 and its co-crystals with diiodoperfluoroalkanes...
June 28, 2017: Chemistry: a European Journal
Esther Cheng, David Ko, Michaela Nguyen, Tracy-Ann Moo, Eleni Andreopoulou, Syed A Hoda, Timothy M D'Alfonso
Residual carcinoma confined to lymphovascular spaces following neoadjuvant chemotherapy (NAC) for invasive breast carcinoma is an uncommon finding. We studied pathologic features and outcome for patients with pure intralymphatic carcinoma (PIC) following NAC, a pattern of residual disease reported to have a poor outcome in the only previously published series of this entity. Six of 284 (2.1%) patients treated with NAC were studied. All 6 patients had axillary lymph node involvement before NAC. Tumors were triple-negative (n=3) and HER2+ (n=3: 2 ER+, 1 ER-)...
June 26, 2017: American Journal of Surgical Pathology
Jing Fan, Shin-Hyun Kim, Zi Chen, Shaobing Zhou, Esther Amstad, Tina Lin, David A Weitz
Compressed monodisperse emulsions in confined space exhibit highly ordered structures. The influence of the volume fraction and the confinement geometry on the organized structures is investigated and the mechanism by which structural transition occurs is studied. Based on the understanding of ordering behavior of compressed emulsions, a simple and high-throughput method to fabricate monodisperse polyhedral microgels using the emulsions as the template is developed. By controlling the geometry of the confined spaces, a variety of shapes such as hexagonal prism, Fejes Toth honeycomb prism, truncated octahedron, pyritohedron, and truncated hexagonal trapezohedron are implemented...
June 26, 2017: Small
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