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https://www.readbyqxmd.com/read/27926842/intact-telopeptides-enhance-interactions-between-collagens
#1
Marjan Shayegan, Tuba Altindal, Evan Kiefl, Nancy R Forde
Collagen is the fundamental structural component of a wide range of connective tissues and of the extracellular matrix. It undergoes self-assembly from individual triple-helical proteins into well-ordered fibrils, a process that is key to tissue development and homeostasis, and to processes such as wound healing. Nucleation of this assembly is known to be slowed considerably by pepsin removal of short nonhelical regions that flank collagen's triple helix, known as telopeptides. Using optical tweezers to perform microrheology measurements, we explored the changes in viscoelasticity of solutions of collagen with and without intact telopeptides...
December 6, 2016: Biophysical Journal
https://www.readbyqxmd.com/read/27926839/circular-dichroism-spectroscopy-of-collagen-fibrillogenesis-a-new-use-for-an-old-technique
#2
Kathryn E Drzewiecki, Daniel R Grisham, Avanish S Parmar, Vikas Nanda, David I Shreiber
Type-I collagen assembles in a stepwise, hierarchic fashion from the folding of the triple helix to the assembly of fibrils into fibers. The mature assembled fibers are crucial for tissue structure and mechanics, cell interactions, and other functions in vivo. Although triple helix folding can be followed with the use of optical methods such as circular dichroism (CD) spectroscopy, fibrillogenesis is typically measured by alternative methods such as turbidity, rheology, and microscopy. Together, these approaches allow for investigation of the mechanical properties and architectures of collagen-based scaffolds and excised tissues...
December 6, 2016: Biophysical Journal
https://www.readbyqxmd.com/read/27926754/cone-photoreceptor-irregularity-on-adaptive-optics-scanning-laser-ophthalmoscopy-correlates-with-severity-of-diabetic-retinopathy-and-macular-edema
#3
Jan Lammer, Sonja G Prager, Michael C Cheney, Amel Ahmed, Salma H Radwan, Stephen A Burns, Paolo S Silva, Jennifer K Sun
Purpose: To determine whether cone density, spacing, or regularity in eyes with and without diabetes (DM) as assessed by high-resolution adaptive optics scanning laser ophthalmoscopy (AOSLO) correlates with presence of diabetes, diabetic retinopathy (DR) severity, or presence of diabetic macular edema (DME). Methods: Participants with type 1 or 2 DM and healthy controls underwent AOSLO imaging of four macular regions. Cone assessment was performed by independent graders for cone density, packing factor (PF), nearest neighbor distance (NND), and Voronoi tile area (VTA)...
December 1, 2016: Investigative Ophthalmology & Visual Science
https://www.readbyqxmd.com/read/27926753/in-vivo-observation-of-lens-regeneration-in-rat-using-ultra-long-scan-depth-optical-coherence-tomography
#4
Kai-Jing Zhou, Yi-Ni Li, Fu-Rong Huang, Qin-Mei Wang, A-Yong Yu
Purpose: To evaluate morphologic changes of lens regeneration in rats in vivo after extracapsular lens extraction (ECLE) by ultra-long scan depth optical coherence tomography (UL-OCT). Methods: A total of 42 Sprague-Dawley rats were used in this study. We performed ECLE on the right eyes of animals in the surgery group (n = 34). Biomicroscopy and UL-OCT scans were carried out for the surgery group immediately (within 1 hour postoperatively) and at days 1 and 3, weeks 1 and 2, and months 1, 2, and 3 postoperatively...
December 1, 2016: Investigative Ophthalmology & Visual Science
https://www.readbyqxmd.com/read/27926751/ocular-perfusion-pressure-and-choroidal-thickness-in-early-age-related-macular-degeneration-patients-with-reticular-pseudodrusen
#5
Cheolmin Yun, Jaemoon Ahn, Minjung Kim, Soon-Young Hwang, Seong-Woo Kim, Jaeryung Oh
Purpose: The purpose of this study was to investigate the relationship between the ocular perfusion pressure (OPP) and subfoveal choroidal thickness (CT) in eyes with early age-related macular degeneration (AMD) with or without reticular pseudodrusen (RPD). Methods: We evaluated the clinical history, blood pressure parameters, fundus photography, and optical coherence tomography images of consecutive patients with early AMD. We calculated the mean OPP from blood pressure and intraocular pressure...
December 1, 2016: Investigative Ophthalmology & Visual Science
https://www.readbyqxmd.com/read/27926746/analysis-and-compensation-for-the-effect-of-the-catheter-position-on-image-intensities-in-intravascular-optical-coherence-tomography
#6
Shengnan Liu, Jeroen Eggermont, Ron Wolterbeek, Alexander Broersen, Carol A G R Busk, Helle Precht, Boudewijn P F Lelieveldt, Jouke Dijkstra
No abstract text is available yet for this article.
December 1, 2016: Journal of Biomedical Optics
https://www.readbyqxmd.com/read/27926579/the-influence-of-coronary-plaque-morphology-assessed-by-optical-coherence-tomography-on-final-microvascular-function-after-stenting-in-patients-with-st-elevation-myocardial-infarction
#7
Giovanni L De Maria, Niket Patel, Mathias Wolfrum, Gregor Fahrni, George Kassimis, Italo Porto, Sam Dawkins, Robin P Choudhury, John C Forfar, Bernard D Prendergast, Keith M Channon, Rajesh K Kharbanda, Hector M Garcia-Garcia, Adrian P Banning
OBJECTIVES: The index of microcirculatory resistance (IMR) provides a reproducible assessment of the status of coronary microvasculature in patients with ST-elevation myocardial infarction (STEMI). Frequency-domain optical coherence tomography (FD-OCT) enables detailed assessment of the morphology of coronary plaque.We sought to determine the influence of the initial culprit coronary plaque anatomy within the infarct-related artery on IMR after stenting in STEMI. PATIENTS AND METHODS: In 25 STEMI patients IMR was measured immediately before and after stent implantation...
December 6, 2016: Coronary Artery Disease
https://www.readbyqxmd.com/read/27925750/high-fidelity-bidirectional-nuclear-qubit-initialization-in-sic
#8
Viktor Ivády, Paul V Klimov, Kevin C Miao, Abram L Falk, David J Christle, Krisztián Szász, Igor A Abrikosov, David D Awschalom, Adam Gali
Dynamic nuclear polarization (DNP) is an attractive method for initializing nuclear spins that are strongly coupled to optically active electron spins because it functions at room temperature and does not require strong magnetic fields. In this Letter, we theoretically demonstrate that DNP, with near-unity polarization efficiency, can be generally realized in weakly coupled electron spin-nuclear spin systems. Furthermore, we theoretically and experimentally show that the nuclear spin polarization can be reversed by magnetic field variations as small as 0...
November 25, 2016: Physical Review Letters
https://www.readbyqxmd.com/read/27925746/single-photon-absorber-based-on-strongly-interacting-rydberg-atoms
#9
C Tresp, C Zimmer, I Mirgorodskiy, H Gorniaczyk, A Paris-Mandoki, S Hofferberth
We report on the realization of a free-space single-photon absorber, which deterministically absorbs exactly one photon from an input pulse. Our scheme is based on the saturation of an optically thick medium by a single photon due to Rydberg blockade. By converting one absorbed input photon into a stationary Rydberg excitation, decoupled from the light field through fast engineered dephasing, we blockade the full atomic cloud and change our optical medium from opaque to transparent. We show that this results in the subtraction of one photon from the input pulse over a wide range of input photon numbers...
November 25, 2016: Physical Review Letters
https://www.readbyqxmd.com/read/27925741/ultratransparent-media-and-transformation-optics-with-shifted-spatial-dispersions
#10
Jie Luo, Yuting Yang, Zhongqi Yao, Weixin Lu, Bo Hou, Zhi Hong Hang, C T Chan, Yun Lai
By using pure dielectric photonic crystals, we demonstrate the realization of ultratransparent media, which allow near 100% transmission of light for all incident angles and create aberration-free virtual images. The ultratransparency effect is well explained by spatially dispersive effective medium theory for photonic crystals, and verified by both simulations and proof-of-principle microwave experiments. Designed with shifted elliptical equal frequency contours, such ultratransparent media not only provide a low-loss and feasible platform for transformation optics devices at optical frequencies, but also enable new freedom for phase manipulation beyond the local medium framework...
November 25, 2016: Physical Review Letters
https://www.readbyqxmd.com/read/27925719/synthetic-dimensions-and-spin-orbit-coupling-with-an-optical-clock-transition
#11
L F Livi, G Cappellini, M Diem, L Franchi, C Clivati, M Frittelli, F Levi, D Calonico, J Catani, M Inguscio, L Fallani
We demonstrate a novel way of synthesizing spin-orbit interactions in ultracold quantum gases, based on a single-photon optical clock transition coupling two long-lived electronic states of two-electron ^{173}Yb atoms. By mapping the electronic states onto effective sites along a synthetic "electronic" dimension, we have engineered fermionic ladders with synthetic magnetic flux in an experimental configuration that has allowed us to achieve uniform fluxes on a lattice with minimal requirements and unprecedented tunability...
November 25, 2016: Physical Review Letters
https://www.readbyqxmd.com/read/27925717/theory-of-enhanced-interlayer-tunneling-in-optically-driven-high-t_-c-superconductors
#12
Jun-Ichi Okamoto, Andrea Cavalleri, Ludwig Mathey
Motivated by recent pump-probe experiments indicating enhanced coherent c-axis transport in underdoped YBCO, we study Josephson junctions periodically driven by optical pulses. We propose a mechanism for this observation by demonstrating that a parametrically driven Josephson junction shows an enhanced imaginary part of the low-frequency conductivity when the driving frequency is above the plasma frequency, implying an effectively enhanced Josephson coupling. We generalize this analysis to a bilayer system of Josephson junctions modeling YBCO...
November 25, 2016: Physical Review Letters
https://www.readbyqxmd.com/read/27924982/upconversion-nanoparticle-as-elemental-tag-for-the-determination-of-alpha-fetoprotein-in-human-serum-by-inductively-coupled-plasma-mass-spectrometry
#13
Zhengru Liu, Bin Yang, Beibei Chen, Man He, Bin Hu
Upconversion nanoparticles (UCNPs) have received increasing attention due to their unique optical properties. Recognizing that UCNPs are lanthanide-doped nanoparticles, we incorporated UCNPs into an immunoassay with inductively coupled plasma mass spectrometry (ICP-MS) detection for the determination of specific proteins, e.g., alpha-fetoprotein (AFP). The sensitivity of the assay was enhanced because of the ICP-MS detection of UCNPs that contained large numbers of lanthanide elemental tags. Conjugates of UCNPs and antibodies were prepared and the morphology of the conjugates was characterized by transmission electron microscopy...
December 7, 2016: Analyst
https://www.readbyqxmd.com/read/27924950/molecular-gated-nanoporous-anodic-alumina-for-the-detection-of-cocaine
#14
Àngela Ribes, Elisabet Xifré-Pérez, Elena Aznar, Félix Sancenón, Teresa Pardo, Lluís F Marsal, Ramόn Martínez-Máñez
We present herein the use of nanoporous anodic alumina (NAA) as a suitable support to implement "molecular gates" for sensing applications. In our design, a NAA support is loaded with a fluorescent reporter (rhodamine B) and functionalized with a short single-stranded DNA. Then pores are blocked by the subsequent hybridisation of a specific cocaine aptamer. The response of the gated material was studied in aqueous solution. In a typical experiment, the support was immersed in hybridisation buffer solution in the absence or presence of cocaine...
December 7, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27924937/deep-sub-wavelength-nanofocusing-of-uv-visible-light-by-hyperbolic-metamaterials
#15
Minkyung Kim, Sunae So, Kan Yao, Yongmin Liu, Junsuk Rho
Confining light into a sub-wavelength area has been challenging due to the natural phenomenon of diffraction. In this paper, we report deep sub-wavelength focusing via dispersion engineering based on hyperbolic metamaterials. Hyperbolic metamaterials, which can be realized by alternating layers of metal and dielectric, are materials showing opposite signs of effective permittivity along the radial and the tangential direction. They can be designed to exhibit a nearly-flat open isofrequency curve originated from the large-negative permittivity in the radial direction and small-positive one in the tangential direction...
December 7, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27924933/all-silicon-ultra-broadband-infrared-light-absorbers
#16
Kazim Gorgulu, Abdullah Gok, Mehmet Yilmaz, Kagan Topalli, Necmi Bıyıklı, Ali K Okyay
Absorbing infrared radiation efficiently is important for critical applications such as thermal imaging and infrared spectroscopy. Common infrared absorbing materials are not standard in Si VLSI technology. We demonstrate ultra-broadband mid-infrared absorbers based purely on silicon. Broadband absorption is achieved by the combined effects of free carrier absorption, and vibrational and plasmonic absorption resonances. The absorbers, consisting of periodically arranged silicon gratings, can be fabricated using standard optical lithography and deep reactive ion etching techniques, allowing for cost-effective and wafer-scale fabrication of micro-structures...
December 7, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27924866/pressure-induced-nano-crystallization-of-silicate-garnets-from-glass
#17
T Irifune, K Kawakami, T Arimoto, H Ohfuji, T Kunimoto, T Shinmei
Transparent ceramics are important for scientific and industrial applications because of the superior optical and mechanical properties. It has been suggested that optical transparency and mechanical strength are substantially enhanced if transparent ceramics with nano-crystals are available. However, synthesis of the highly transparent nano-crystalline ceramics has been difficult using conventional sintering techniques at relatively low pressures. Here we show direct conversion from bulk glass starting material in mutianvil high-pressure apparatus leads to pore-free nano-polycrystalline silicate garnet at pressures above ∼10 GPa in a limited temperature range around 1,400 °C...
December 7, 2016: Nature Communications
https://www.readbyqxmd.com/read/27924859/nano-cones-for-broadband-light-coupling-to-high-index-substrates
#18
J Buencuerpo, L Torné, R Álvaro, J M Llorens, M L Dotor, J M Ripalda
The moth-eye structure has been proposed several times as an antireflective coating to replace the standard optical thin films. Here, we experimentally demonstrate the feasibility of a dielectric moth-eye structure as an antireflective coating for high-index substrates, like GaAs. The fabricated photonic crystal has Si3N4 cones in a square lattice, sitting on top of a TiO2 index matching layer. This structure attains 1.4% of reflectance power losses in the operation spectral range of GaAs solar cells (440-870 nm), a 12...
December 7, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27924844/designing-a-broadband-pump-for-high-quality-micro-lasers-via-modified-net-radiation-method
#19
Sergey Nechayev, Philip D Reusswig, Marc A Baldo, Carmel Rotschild
High-quality micro-lasers are key ingredients in non-linear optics, communication, sensing and low-threshold solar-pumped lasers. However, such micro-lasers exhibit negligible absorption of free-space broadband pump light. Recently, this limitation was lifted by cascade energy transfer, in which the absorption and quality factor are modulated with wavelength, enabling non-resonant pumping of high-quality micro-lasers and solar-pumped laser to operate at record low solar concentration. Here, we present a generic theoretical framework for modeling the absorption, emission and energy transfer of incoherent radiation between cascade sensitizer and laser gain media...
December 7, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27924624/dielectric-like-behavior-of-graphene-in-au-plasmon-resonator
#20
Junku Liu, Qunqing Li, Mo Chen, Mengxin Ren, Lihui Zhang, Lin Xiao, Kaili Jiang, Shoushan Fan
Graphene has proven to be a promising conductive layer in fabricating optical plasmon resonators on insulator substrate using electron beam lithography and has the potential to construct electrically controlled active plasmon resonators. In this study, we investigate the effect of graphene on plasmon resonance using graphene and Au plasmon resonator system as a model at visible and near-infrared wavelength. Our experiment data show that the presence of graphene does not weaken and annihilate the plasmon resonance peaks, instead it predominantly makes the peaks redshift, which is similar to the behavior of depositing SiO2 film on Au plasmon resonators...
December 2016: Nanoscale Research Letters
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