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https://www.readbyqxmd.com/read/29135463/new-method-for-mbe-growth-of-gaas-nanowires-on-silicon-using-colloidal-au-nanoparticles
#1
Alexei Bouravleuv, Igor Ilkiv, Rodion Reznik, Konstantin Kotlyar, Ilya Soshnikov, George Cirlin, Pavel Brunkov, Demid Kirilenko, Leonid V Bondarenko, Aleksandr Nepomnyaschiy, Dimitry V Gruznev, Andrey V Zotov, Alexander Saranin, Veer Dhaka, Harri Lipsanen
We present a new method for the deposition of colloidal Au nanoparticles on the surface of silicon substrates based on short-time Ar plasma treatment without the use of any polymeric layers. The elaborated method is compatible with molecular beam epitaxy, which allowed us to carry out the detailed study of GaAs nanowire synthesis on Si(111) substrates using colloidal Au nanoparticles as seeds for their growth. The results obtained elucidated the causes of the difference between the initial nanoparticle sizes and the diameters of the grown nanowires...
November 14, 2017: Nanotechnology
https://www.readbyqxmd.com/read/29130887/axial-p-n-junction-and-space-charge-limited-current-in-single-gan-nanowire
#2
Zhihua Fang, Fabrice Donatini, Bruno Daudin, Julien Pernot
The electrical characterizations of individual basic GaN nanostructures, such as axial nanowire (NW) p-n junctions, are becoming indispensable and crucial for the fully controlled realization of GaN NW based devices. In this study, electron beam induced current (EBIC) measurements were performed on two single axial GaN p-n junction NWs grown by plasma-assisted molecular beam epitaxy. I-V characteristics revealed that both ohmic and space charge limited current (SCLC) regimes occur in GaN p-n junction NW. Thanks to an improved contact process, both the electric field induced by the p-n junction and the SCLC in the p-part of GaN NW were disclosed and delineated by EBIC signals under different biases...
November 13, 2017: Nanotechnology
https://www.readbyqxmd.com/read/29129780/prior-radiation-therapy-decreases-time-to-idiopathic-erosion-of-artificial-urinary-sphincter-a-multi-institutional-analysis
#3
Melissa R Kaufman, Douglas F Milam, Niels V Johnsen, Mario A Cleves, Joshua A Broghammer, William O Brant, LeRoy A Jones, Jeffrey D Brady, Martin S Gross, Gerard D Henry
PURPOSE: Substantial controversy and conflicting data exist regarding device survival of the artificial urinary sphincter (AUS) in patients with prior radiation therapy. Herein we present data from a multi-institutional analysis examining the effect of prior radiation for prostate cancer on device survival. MATERIALS AND METHODS: A database was compiled of AUS cuff erosion patients including demographic and comorbid patient characteristics, functional analyses, and interventions...
November 9, 2017: Journal of Urology
https://www.readbyqxmd.com/read/29125035/cone-beam-computed-tomography-cbct-for-adaptive-image-guided-head-and-neck-radiation-therapy
#4
Christian A Hvid, Ulrik V Elstrøm, Kenneth Jensen, Cai Grau
BACKGROUND: Adaptive (ART) and image guided radiation therapy (IGRT) can improve target coverage and reduce unnecessary irradiation of organs at risk (OAR). The purpose of this study is to report the results of using mid-course imaging and a novel workflow with cone-beam computed tomography (CBCT) surveillance of dose to OAR to trigger adaptive replanning in head and neck radiotherapy. MATERIAL AND METHODS: Impact of radiation therapist (RTT) managed match protocol and mid-course imaging was assessed in two cohorts of consecutive patients receiving RT to the head and neck region, using computed tomography (CT) and CBCT-based dose verification respectively...
November 10, 2017: Acta Oncologica
https://www.readbyqxmd.com/read/29120866/surface-effects-on-exciton-diffusion-in-non-polar-zno-znmgo-heterostructures
#5
G Sakr, C Sartel, V Sallet, A Lusson, G Patriarche, P Galtier, J Barjon
The diffusion of excitons injected in ZnO/Zn0.92Mg0.08O quantum well heterostructures grown by metal-organic-vapor-phase-epitaxy on non-polar ZnO substrates is investigated at room temperature. Cathodoluminescence linescans in a field-emission-gun scanning-electron-microscope are performed across cleaved cross-sections. A 55 nm diffusion length is assessed for excitons in bulk ZnMgO. When prepared as small angle bevels using focused ion beam (FIB), the effective diffusion length of excitons is shown to decrease down to 8 nm in the thinner part of the slab...
November 9, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/29116966/effect-of-beam-steering-on-echogenic-and-nonechogenic-needle-visibility-at-40%C3%A2-50%C3%A2-and-60%C3%A2-needle-insertion-angles
#6
Christopher Prabhakar, Vishal Uppal, Rakesh V Sondekoppam
Currently, there is little understanding of the role of echogenic needles and beam steering at moderate angles of needle insertion. The ultrasound images of the echogenic and nonechogenic needles inserted into pork at 40°, 50°, and 60° were scored by anesthesiologists on a scale of 0-10. The effect of different levels of beam steer was also explored. At 40°, steep beam steering improves visualization of both nonechogenic and echogenic needles to an equal, satisfactory level. At 50° and 60°, visualization of nonechogenic needles is poor, whereas visibility of an echogenic needle was adequate and may be improved with steep beam steering...
November 7, 2017: Anesthesia and Analgesia
https://www.readbyqxmd.com/read/29114613/acr-appropriateness-criteria-for-external-beam-radiation-therapy-treatment-planning-for-clinically-localized-prostate-cancer-part-ii-of-ii
#7
REVIEW
Nicholas G Zaorsky, Timothy N Showalter, Gary A Ezzell, Paul L Nguyen, Dean G Assimos, Anthony V D'Amico, Alexander R Gottschalk, Gary S Gustafson, Sameer R Keole, Stanley L Liauw, Shane Lloyd, Patrick W McLaughlin, Benjamin Movsas, Bradley R Prestidge, Al V Taira, Neha Vapiwala, Brian J Davis
Purpose: To present the most updated American College of Radiology (ACR) Appropriateness Criteria formed by an expert panel on the appropriate delivery of external beam radiation to manage stage T1 and T2 prostate cancer (in the definitive setting and post-prostatectomy) and to provide clinical variants with expert recommendations based on accompanying Appropriateness Criteria for target volumes and treatment planning. Methods and materials: The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a panel of multidisciplinary experts...
July 2017: Advances in Radiation Oncology
https://www.readbyqxmd.com/read/29109746/comparative-evaluation-of-root-canal-morphology-of-mandibular-premolars-using-clearing-and-cone-beam-computed-tomography
#8
Abbasali Khademi, Mojdeh Mehdizadeh, Maryam Sanei, Hamidreza Sadeqnejad, Saber Khazaei
Background: Different techniques are used to evaluate the anatomy of root canal system. The present study was aimed to evaluate the root canal morphology of mandibular premolars using clearing and cone beam computed tomography (CBCT) techniques. Materials and Methods: A total of 182 mandibular first and second premolars were evaluated in vitro using 100 μm CBCT cross sections. The root canal morphology of the teeth was determined based on Vertucci classification in relation to the prevalence of C-shaped canals, lateral canals, and furcation location...
September 2017: Dental Research Journal
https://www.readbyqxmd.com/read/29109055/characterization-of-oromotor-and-limb-motor-dysfunction-in-the-dj1-model-of-parkinson-disease
#9
Katie M Yang, Katherine V Blue, Haleigh M Mulholland, Meghna P Kurup, Cynthia A Kelm-Nelson, Michelle R Ciucci
Parkinson disease (PD) is devastating to sensorimotor function that includes cranial/oromotor and limb motor deficits. However, the onset, progression, and neural correlates of PD-related dysfunctions are poorly understood. To address this gap, we used a genetic rat model of PD, DJ1 -/-, and hypothesized that motor deficits would manifest early in the disease process, be progressive in nature, and be related to pathologies in brainstem structures associated with sensorimotor function. The present study compares homozygous DJ1 -/- male rats to age-matched wild type controls...
November 3, 2017: Behavioural Brain Research
https://www.readbyqxmd.com/read/29107062/the-anti-aging-protein-klotho-alleviates-injury-of-nigrostriatal-dopaminergic-pathway-in-6-hydroxydopamine-rat-model-of-parkinson-s-disease-involvement-of-pka-camkii-creb-signaling
#10
Tourandokht Baluchnejadmojarad, Seyed-Mohammad Eftekhari, Nida Jamali-Raeufy, Sobhan Haghani, Hossein Zeinali, Mehrdad Roghani
Parkinson's disease (PD) is a prevalent movement disorder in the elderly. PD is hallmarked with progressive deterioration of mesencephalic dopaminergic neurons and development of debilitating motor and non-motor clinical symptoms. Klotho protein is the product of an aging-suppressor gene that its overexpression could protect neurons against oxidative injury. This study was undertaken to explore whether exogenous klotho could alleviate injury of nigrostriatal dopaminergic pathway in 6-hydroxydopamine (6-OHDA) rat model of PD...
October 31, 2017: Experimental Gerontology
https://www.readbyqxmd.com/read/29106564/modelling-recurrence-and-second-cancer-risks-induced-by-proton-therapy
#11
V S K Manem, A Dhawan
In the past few years, proton therapy has taken the centre stage in treating various tumour types. The primary contribution of this study is to investigate the tumour control probability (TCP), relapse time and the corresponding secondary cancer risks induced by proton beam radiation therapy. We incorporate tumour relapse kinetics into the TCP framework and calculate the associated second cancer risks. To calculate proton therapy-induced secondary cancer induction, we used the well-known biologically motivated mathematical model, initiation-inactivation-proliferation formalism...
July 4, 2017: Mathematical Medicine and Biology: a Journal of the IMA
https://www.readbyqxmd.com/read/29104299/ultra-thin-metasurface-microwave-flat-lens-for-broadband-applications
#12
Abul K Azad, Anatoly V Efimov, Shuprio Ghosh, John Singleton, Antoinette J Taylor, Hou-Tong Chen
We demonstrate a metasurface-based ultrathin flat lens operating at microwave frequencies. A series of subwavelength metallic split-ring resonators, which are sandwiched between two cross-polarized metallic gratings, are defined to obtain a radially symmetric parabolic phase distribution, covering relative phase differences ranging from 0 to 2.5π radians to create a lens. The tri-layer lens exhibits focusing/collimating of broadband microwaves from 7.0 to 10.0 GHz, with a gain enhancement of 17 dBi at a central wavelength 9...
May 29, 2017: Applied Physics Letters
https://www.readbyqxmd.com/read/29103834/changes-in-condylar-volume-and-joint-spaces-after-orthognathic-surgery
#13
R J da Silva, C V Valadares Souza, G A Souza, G M B Ambrosano, D Q Freitas, E Sant'Ana, C de Oliveira-Santos
The aim of this study was to evaluate the changes in condylar volume and joint spaces occurring in patients undergoing bimaxillary orthognathic surgery for the treatment of class II deformities, by means of cone beam computed tomography (CBCT). Initial and follow-up (at least 6 months) CBCT examinations of 114 condyles (57 patients) were studied retrospectively. Linear measurements of the joint space and volumetric analysis of changes in condylar volume were performed using Dolphin 3D Imaging in association with ITK-SNAP 3...
November 2, 2017: International Journal of Oral and Maxillofacial Surgery
https://www.readbyqxmd.com/read/29097720/pink-beam-serial-crystallography
#14
A Meents, M O Wiedorn, V Srajer, R Henning, I Sarrou, J Bergtholdt, M Barthelmess, P Y A Reinke, D Dierksmeyer, A Tolstikova, S Schaible, M Messerschmidt, C M Ogata, D J Kissick, M H Taft, D J Manstein, J Lieske, D Oberthuer, R F Fischetti, H N Chapman
Serial X-ray crystallography allows macromolecular structure determination at both X-ray free electron lasers (XFELs) and, more recently, synchrotron sources. The time resolution for serial synchrotron crystallography experiments has been limited to millisecond timescales with monochromatic beams. The polychromatic, "pink", beam provides a more than two orders of magnitude increased photon flux and hence allows accessing much shorter timescales in diffraction experiments at synchrotron sources. Here we report the structure determination of two different protein samples by merging pink-beam diffraction patterns from many crystals, each collected with a single 100 ps X-ray pulse exposure per crystal using a setup optimized for very low scattering background...
November 3, 2017: Nature Communications
https://www.readbyqxmd.com/read/29094524/multiscale-sensorless-adaptive-optics-oct-angiography-system-for-in-vivo-human-retinal-imaging
#15
Myeong Jin Ju, Morgan Heisler, Daniel Wahl, Yifan Jian, Marinko V Sarunic
We present a multiscale sensorless adaptive optics (SAO) OCT system capable of imaging retinal structure and vasculature with various fields-of-view (FOV) and resolutions. Using a single deformable mirror and exploiting the polarization properties of light, the SAO-OCT-A was implemented in a compact and easy to operate system. With the ability to adjust the beam diameter at the pupil, retinal imaging was demonstrated at two different numerical apertures with the same system. The general morphological structure and retinal vasculature could be observed with a few tens of micrometer-scale lateral resolution with conventional OCT and OCT-A scanning protocols with a 1...
November 2017: Journal of Biomedical Optics
https://www.readbyqxmd.com/read/29092237/on-chip-free-beam-optics-on-a-polymer-based-photonic-integration-platform
#16
M Happach, D de Felipe, H Conradi, V N Friedhoff, E Schwartz, M Kleinert, W Brinker, C Zawadzki, N Keil, W Hofmann, M Schell
This paper presents on-chip free beam optics on polymer-based photonic components. Due to the circumstance that waveguide-based optics allows no direct beam access we use Gradient index (GRIN) lenses assembled into the chip to collimate the beam from the waveguides. This enables low loss power transmission over a length of 1432 µm. Even though the beam propagates through air it is possible to create a resonator with a wavelength shift of 0.002 nm/°C, hence the allowed deviations from the ITU-T grid (100 GHz) are met for ± 20 °C...
October 30, 2017: Optics Express
https://www.readbyqxmd.com/read/29091649/fractional-airy-beams
#17
S N Khonina, A V Ustinov
Airy beams possess a number of properties that ensure their multifunction and high relevance in many applications. This fact stimulates scientists to search for new modifications and generalizations of classical Airy beams. Several generalizations of the Airy functions are known, on the basis of both the modification of the differential equation and the variations in the integral representation. In this paper we propose and investigate a new type of Airy beams-fractional Airy beams (FrAiB). They are based on the generalization of the integral representation and are close to the Olver functions, but we are considering a wider range of the power-law dependence of the argument, including non-integer (fractional) values of the power...
November 1, 2017: Journal of the Optical Society of America. A, Optics, Image Science, and Vision
https://www.readbyqxmd.com/read/29091634/ray-tracing-in-ellipsoidal-reflectors-for-optical-biometry-of-media
#18
M A Bezuglyi, N V Bezuglaya, I V Helich
In this paper, an analytical basis of ray tracing for optical biometry of media by ellipsoidal reflectors was developed. A ray-tracing algorithm was created, which involves determining the point of interaction of the incident beam with the ellipsoidal reflector, calculating the direction of the reflected beam, and determining the intersection point of the reflected ray with the second ellipsoid focal plane, taking into account the statistical weight of photons. For imaging in the optical biometry of media by ellipsoidal reflectors, the results of a real experiment and a Monte Carlo simulation for chicken muscle tissue samples of different thicknesses for the wavelength of 632...
October 20, 2017: Applied Optics
https://www.readbyqxmd.com/read/29091056/refraction-and-ultra-small-angle-scattering-of-x-rays-in-a-single-crystal-diamond-compound-refractive-lens
#19
S Gasilov, A Mittone, T Dos Santos Rolo, S Polyakov, S Zholudev, S Terentyev, V Blank, A Bravin, T Baumbach
In this work a double-crystal setup is employed to study compound refractive lenses made of single-crystal diamond. The point spread function of the lens is calculated taking into account the lens transmission, the wavefront aberrations, and the ultra-small-angle broadening of the X-ray beam. It is shown that, similarly to the wavefront aberrations, the ultra-small-angle scattering effects can significantly reduce the intensity gain and increase the focal spot size. The suggested approach can be particularly useful for the characterization of refractive X-ray lenses composed of many tens of unit lenses...
November 1, 2017: Journal of Synchrotron Radiation
https://www.readbyqxmd.com/read/29090928/rapid-and-controlled-in-situ-growth-of-noble-metal-nanostructures-within-halloysite-clay-nanotubes
#20
Taha Rostamzadeh, Md Shahidul Islam Khan, Kyle Riche', Yuri M Lvov, Anna V Stavitskaya, John B Wiley
A rapid (≤2 min) and high-yield low-temperature synthesis has been developed for the in situ growth of gold nanoparticles (NPs) with controlled sizes in the interior of halloysite nanotubes (HNTs). A combination of HAuCl4 in ethanol/toluene, oleic acid, and oleylamine surfactants and ascorbic acid reducing agent with mild heating (55 °C) readily lead to the growth of targeted nanostructures. The sizes of Au NPs are tuned mainly by adjusting nucleation and growth rates. Further modification of the process, through an increase in ascorbic acid, allows for the formation of nanorods (NRs)/nanowires within the HNTs...
November 1, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
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