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Confined Spaces

Carmelo Andújar, Sergio Pérez-González, Paula Arribas, Juan P Zaballos, Alfried P Vogler, Ignacio Ribera
Dispersal is a critical factor determining the spatial scale of speciation, which is constrained by the ecological characteristics and distribution of a species' habitat and the intrinsic traits of species. Endogean taxa are strongly affected by the unique qualities of the below-ground environment and its effect on dispersal, and contrasting reports indicate either high dispersal capabilities favoured by small body size and mediated by passive mechanisms, or low dispersal due to restricted movement and confinement inside the soil...
September 19, 2017: Molecular Ecology
Michael Å Petersen, Brian Rasmussen, Nicolaj N Andersen, Stephan P A Sauer, Mogens Brøndsted Nielsen, Sophie R Beeren, Michael Pittelkow
Confinement of reactive chemical species uniquely affects chemical reactivity by restricting the physical space available and by restricting access to interactions with the solvent. In Nature, for example, confined protein binding pockets govern processes following photoisomerization reactions and the isomerizations themselves. Here we describe the first example of a dihydroazulene/vinylheptafulvene (DHA/VHF) photo-switch functioning in water, and we show how its switching behavior is strongly influenced by supramolecular interactions with a series of cucurbit[n]uril (CB) host molecules...
September 18, 2017: Chemistry: a European Journal
Masahiro Kinoshita, Tomohiko Hayashi
The association of nonpolar solutes is generally believed to be entropy driven, which has been shown to be true for the contact of small molecules, ellipsoids, and plates. However, it has been reported with surprise that a model cavity-ligand binding is entropy opposed. How can these apparently conflicting behaviors be elucidated? Here, we calculate the potential of mean force between hard-sphere solutes with various diameters in water and its entropic and enthalpic components using a statistical-mechanical theory for molecular liquids...
September 18, 2017: Physical Chemistry Chemical Physics: PCCP
Natalia Martín Sabanés, Katrin F Domke
Electrochemistry is re-gaining attention among scientists because the complex interplay between electronic and chemical interfacial processes lies at the bottom of a broad range of important research disciplines like alternative energy conversion or green catalysis and synthesis. While rapid progress has been made in recent years regarding novel technological applications, the community increasingly recognizes that the understanding of the molecular processes that govern macroscopic device properties is still rather limited - which hinders a systematic and more complete exploration of novel material and functionality space...
August 2017: ChemElectroChem
A Bohórquez-Hernández, Enrico Gratton, Jonathan Pacheco, Alexander Asanov, Luis Vaca
Store Operated Calcium Entry (SOCE) is one of the most important mechanisms for calcium mobilization in to the cell. Two main proteins sustain SOCE: STIM1 that acts as the calcium sensor in the endoplasmic reticulum (ER) and Orai1 responsible for calcium influx upon depletion of ER. There are many studies indicating that SOCE is modulated by the cholesterol content of the plasma membrane (PM). However, a myriad of questions remain unanswered concerning the precise molecular mechanism by which cholesterol modulates SOCE...
September 12, 2017: Biochimica et Biophysica Acta
Zhili Li, Zhen Wang, Fan Yang, Wei Jin, Wei Ren
We demonstrate mid-infrared photothermal interferometry (PTI) in a hollow-core fiber (HCF) for trace gas detection. Compared with free-space PTI, the optical intensity could be increased by orders of magnitude by confining the pump and probe lights in the hollow core. We coupled the pump light at 4.46 μm from a quantum cascade laser and the 1555.14 nm probe light into the HCF with a bore size of 200 μm. The HCF was filled with nitrous oxide (N2O) which has strong absorption at the pump wavelength. The probe light detects the N2O absorption-induced phase change in the HCF via a fiber-optic Mach-Zehnder interferometer...
September 15, 2017: Optics Letters
Julian Di Guilmi, Maria Cecilia Darin, Maria Toscano, Gustavo Maya
OBJECTIVE: To demonstrate the initial experience in Argentina using the iSpies ICG platform in performing sentinel lymph node mapping in early-stage cervical cancer. Design Step-by-step video and pictures BACKGROUND: Laparoscopic and robotic sentinel lymph node mapping using ICG has been shown to be safe and feasible. However, the use of fluorescent imaging through a minimally invasive approach in developing countries is very limited given the cost restrictions of acquiring the near infrared technology and the fluorescent dyes...
September 11, 2017: Journal of Minimally Invasive Gynecology
Hui Wang, Can Wei, Kaiyi Zhu, Yu Zhang, Chunhong Gong, Jianhui Guo, JiWei Zhang, Laigui Yu, Jingwei Zhang
A novel electrochemical exfoliation mode was established to prepare graphene sheets efficiently with potential applications in transparent conductive films. The graphite electrode was coated with paraffin to keep the electrochemical exfoliation in confined space in the presence of concentrated sodium hydroxide as the electrolyte, yielding ~100% low-defect (the D band to G band intensity ratio ID/IG = 0.26) graphene sheets. Furthermore, ozone was first detected with ozone test strips, and the effect of ozone on the exfoliation of graphite foil and the microstructure of the as-prepared graphene sheets was investigated...
September 13, 2017: ACS Applied Materials & Interfaces
Lothar A Blatter
Many cellular functions of the vascular endothelium are regulated by fine-tuned global and local, microdomain-confined changes of cytosolic free Ca(2+) ([Ca(2+)]i). Vasoactive agonist-induced stimulation of vascular endothelial cells (VECs) typically induces Ca(2+) release through IP3 receptor Ca(2+) release channels embedded in the membrane of the endoplasmic reticulum (ER) Ca(2+) store, followed by Ca(2+) entry from the extracellular space elicited by Ca(2+) store depletion and referred to as capacitative or store-operated Ca(2+) entry (SOCE)...
2017: Advances in Experimental Medicine and Biology
András Spät, Gergö Szanda
Mitochondria extensively modify virtually all cellular Ca(2+) transport processes, and store-operated Ca(2+) entry (SOCE) is no exception to this rule. The interaction between SOCE and mitochondria is complex and reciprocal, substantially altering and, ultimately, fine-tuning both capacitative Ca(2+) influx and mitochondrial function. Mitochondria, owing to their considerable Ca(2+) accumulation ability, extensively buffer the cytosolic Ca(2+) in their vicinity. In turn, the accumulated ion is released back into the neighboring cytosol during net Ca(2+) efflux...
2017: Advances in Experimental Medicine and Biology
Jan Heckmann, Riccardo Scott, Anatol V Prudnikau, Artsiom Antanovich, Nina Owschimikow, Mikhail Artemyev, Juan I Climente, Ulrike Woggon, Nicolai B Grosse, Alexander W Achtstein
We show that two-photon absorption (TPA) is highly anisotropic in CdSe nanoplatelets, thus promoting them as a new class of directional two-photon absorbers with large cross sections. Comparing two-dimensional k-space spectroscopic measurements of the one-photon and two-photon excitation of an oriented monolayer of platelets, it is revealed that TPA into the continuum is a directional phenomenon. This is in contrast to one-photon absorption. The observed directional TPA is shown to be related to fundamental band anisotropies of zincblende CdSe and the ultrastrong anisotropic confinement...
September 18, 2017: Nano Letters
Ziyang Lu, Martin H Klein Schaarsberg, Xiaojue Zhu, Leslie Y Yeo, Detlef Lohse, Xuehua Zhang
We report the self-organization of universal branching patterns of oil nanodroplets under the Ouzo effect [Vitale S, Katz J (2003) Langmuir 19:4105-4110]-a phenomenon in which spontaneous droplet formation occurs upon dilution of an organic solution of oil with water. The mixing of the organic and aqueous phases is confined under a quasi-2D geometry. In a manner analogous to the ramification of ground stream networks [Devauchelle O, Petroff AP, Seybold HF, Rothman DH (2012) Proc Natl Acad Sci USA 109: 20832-20836 and Cohen Y, et al...
September 11, 2017: Proceedings of the National Academy of Sciences of the United States of America
S Assali, J Lähnemann, T T T Vu, K D Jöns, L Gagliano, M A Verheijen, N Akopian, E P A M Bakkers, J E M Haverkort
One of the major challenges in the growth of quantum well and quantum dot heterostructures is the realization of atomically sharp interfaces. Nanowires provide a new opportunity to engineer the band structure as they facilitate the controlled switching of the crystal structure between the zinc-blende (ZB) and wurtzite (WZ) phases. Such a crystal phase switching results in the formation of crystal phase quantum wells (CPQWs) and quantum dots (CPQDs). For GaP CPQWs, the inherent electric fields due to the discontinuity of the spontaneous polarization at the WZ/ZB junctions lead to the confinement of both types of charge carriers at the opposite interfaces of the WZ/ZB/WZ structure...
September 18, 2017: Nano Letters
T Kuhnel, H Jagle, W Hosemann, R Weber, V Vielsmeier
To avoid the dangers associated with lower eyelid approaches to the orbital floor and to improve visualization, we propose an endoscopic procedure for orbital floor fracture reduction and osteosynthesis using endonasal access via the medial maxillary sinus wall. The technique of endoscopic, endonasal transantral surgery is described, together with a retrospective analysis of 17 patients who had undergone this surgical procedure in the Department of Otorhinolaryngology, University of Regensburg, between July 2013 and June 2016...
September 9, 2017: Rhinology
Shuo Wang, Yude Liu, Wentian Shi, Bin Qi, Jin Yang, Feifei Zhang, Dong Han, Yingyi Ma
Selective laser melting (SLM) is a potential additive manufacturing (AM) technology. However, the application of SLM was confined due to low efficiency. To improve efficiency, SLM fabrication with a high layer thickness and fine powder was systematically researched, and the void areas and hollow powders can be reduced by using fine powder. Single-track experiments were used to narrow down process parameter windows. Multi-layer fabrication relative density can be reached 99.99% at the exposure time-point distance-hatch space of 120 μs-40 μm-240 μm...
September 8, 2017: Materials
Sarah D Hann, Kathleen J Stebe, Daeyeon Lee
In nature, the environment surrounding biomolecules and living cells can dictate their structure, function, and properties. Confinement is a key means to define and regulate such environments. For example, confinement of appropriate constituents in compartments facilitates the assembly, dynamics and function of biochemical machineries as well as subcellular organelles. Membrane-less organelles, in particular, are thought to form via thermodynamic cues defined within the interior space of cells. On larger length scales, confinement of living cells dictates cellular function for both mammalian and bacterial cells...
September 7, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Sijing Yi, Jiao Wang, Zhenyu Feng, Xiao Chen
Soft materials of europium β-diketonate complexes constructed in lyotropic liquid crystals (LLCs) mediated by ionic liquids (ILs) are impressive for their excellent luminescence performance and stability. For the aim to further improve their mechanical processability and luminescent tunablility, the polyoxyethylene phytosterols (BPS-n) were introduced here as structure directing agents to prepare relatively "rigid" lamellar luminescent LLCs in 1-butyl-3-methyl-imidazolium hexafluorophosphate by doping europium β-diketonate complexes with different imidazolium counter ions...
September 6, 2017: Journal of Physical Chemistry. B
Yuki Taniguchi, Muhammad Adli Bin Sazali, Yusei Kobayashi, Noriyoshi Arai, Tsuyoshi Kawai, Takuya Nakashima
Site-selective surface modification on the shape-controlled nanocrystals is a key approach in the programmed self-assembly of inorganic colloidal materials. This study demonstrates a simple methodology to gain self-assemblies of semiconductor nanocrystals with branched shapes through tip-to-tip attachment. Short-chained water-soluble cationic thiols are employed as a surface ligand for CdSe tetrapods and CdSe/CdS core/shell octapods. Because of the less affinity of arm-tip to the surface ligands compared to the arm-side wall, the tip-surface becomes uncapped to give a hydrophobic nature, affording an amphiphilic surface pattern...
September 8, 2017: ACS Nano
Soroush Shabahang, H Esat Kondakci, Massimo L Villinger, Joshua D Perlstein, Ahmed El Halawany, Ayman F Abouraddy
Optical cavities transmit light only at discrete resonant frequencies, which are well-separated in micro-structures. Despite attempts at the construction of planar 'white-light cavities', the benefits accrued upon optically interacting with a cavity - such as resonant field buildup - have remained confined to narrow linewidths. Here, we demonstrate achromatic optical transmission through a planar Fabry-Pérot micro-cavity via angularly multiplexed phase-matching that exploits a bio-inspired grating configuration...
September 4, 2017: Scientific Reports
Yajie Yu, Chao Liang, Meiling Bao, Pengfei Shao, Zengjun Wang
BACKGROUND: Currently, the standard treatment for renal pelvis carcinoma is radical nephroureterectomy with bladder cuff excision. To describe the feasibility of retroperitoneal laparoscopic partial nephrectomy with segmental renal artery clamping for cancer of renal pelvis, we report this special case for the first time. CASE PRESENTATION: A 67-year-old woman received this operation. Preoperative ureteroscopy revealed a papillary neoplasm with a pedicle in the upper calyx of the left kidney...
August 31, 2017: BMC Urology
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