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frequency compression

Ashish Kumar Singh, Bo-Yang Chen, Vincent B C Tan, Tong-Earn Tay, Heow-Pueh Lee
Linear ultrasonics methods based on the principle of reflection, transmission, dissipation of sound waves have been traditionally used to detect delaminations in composite structures. However, when the delamination is in very early stages such that it is almost closed, or closed due to a compressive load, the linear methods may fail to detect such cases of delaminations. Nonlinear acoustics/ultrasonics have shown potential to identify damages in composite structures which are difficult to detect using conventional linear ultrasonic methods...
October 8, 2016: Ultrasonics
Rolf E Isele-Holder, Julia Jäger, Guglielmo Saggiorato, Jens Elgeti, Gerhard Gompper
Worm-like filaments, which are propelled by a tangential homogeneous force along their contour, are studied as they push loads of different shapes and sizes. The resulting dynamics is investigated using Langevin dynamics simulations. The effects of size and shape of the load, propulsion strength, and thermal noise are systematically explored. The propulsive force and hydrodynamic friction of the load cause a compression in the filament that results in a buckling instability and versatile motion. Distinct regimes of elongated filaments, curved filaments, beating filaments, and filaments with alternating beating and circular motion are identified, and a phase diagram depending on the propulsion strength and the size of the load is constructed...
October 19, 2016: Soft Matter
Jonathan T Kaplan, Corey P Neu, Hicham Drissi, Nancy C Emery, David M Pierce
Osteoarthritis and articular cartilage injuries are common conditions in human joints and a frequent cause of pain and disability. Unfortunately, cartilage is avascular and has limited capabilities for self-repair. Despite the societal impact, there is little information on the dynamic process of cartilage degeneration. We performed a series of cyclic unconfined compression tests motivated by in vivo loading conditions and designed to generate mechanical fatigue. We examined the functional (both stress-stretch and creep) responses of the tissue after recovery from a specified number of loading cycles, as well as histology and second harmonic generation microscopy images...
October 1, 2016: Journal of the Mechanical Behavior of Biomedical Materials
Muhsin Nuh Aybay, Ibrahim Guler, Ozgur Oner, Suleyman Baktik, Ali Fuat Tekin
Hydatid cyst is an endemically seen parasitic disease and caused by the larval form of Echinococcus parasites. The disease is mostly seen in liver and lung, and the other involvement is rarely seen. Head and neck involvement is extremely rarely seen and its frequency in the literature is reported as less than 1%. It is usually asymptomatic and the symptoms are related to the compression to the adjacent structures. In this paper, the authors report a patient of hydatid cyst localized in the posterior cervical region...
October 14, 2016: Journal of Craniofacial Surgery
Ji Zhou, Yaojun Qiao, Zhanyu Yang, Erkun Sun
In this Letter, we propose, to the best of our knowledge, the first faster-than-Nyquist non-orthogonal frequency-division multiplexing based on fractional Hartley transform (FrHT). Different from the existing NOFDM signal, the real-valued FrHT-based NOFDM signal can be directly applied to an intensity-modulated/direct-detection optical system without upconversion, and it can achieve a transmission rate faster than the Nyquist rate, which is the up limit of orthogonal frequency-division multiplexing. For example, when bandwidth compression factor α is set to 0...
October 1, 2016: Optics Letters
Nathaniel Bell, Bo Cai
BACKGROUND: Our objective was to evaluate the reliability and predictability of ten socioeconomic indicators obtained from the 2006-2013 annual and multi-year ACS data cycles for unintentional drowning and submersion injury surveillance. METHODS: Each indicator was evaluated using its margin of error and coefficient of variation. For the multi-year data cycles we calculated the frequency that estimates for the same geographic areas from consecutive surveys were statistically significantly different...
December 2015: Injury Epidemiology
Constantin von Kirschbaum, Robert Gürkov
Introduction. Vestibular schwannomas (VS) are benign tumours of the vestibular nerve and can lead to hearing loss, tinnitus, vertigo, facial palsy, and brainstem compression. Audiovestibular diagnostic tests are essential for detection and treatment planning. Methods. Medline was used to perform a systematic literature review with regard to how audiovestibular test parameters correlate with symptoms, tumour size, and tumour location. Results. The auditory brainstem response can be used to diagnose retrocochlear lesions caused by VS...
2016: BioMed Research International
Abdul Haseeb Ahmed, Ijaz M Qureshi, Jawad Ali Shah, Muhammad Zaheer
Respiratory motion during Magnetic Resonance (MR) acquisition causes strong blurring artifacts in the reconstructed images. These artifacts become more pronounced when use with the fast imaging reconstruction techniques like compressed sensing (CS). Recently, an MR reconstruction technique has been done with the help of compressed sensing (CS), to provide good quality sparse images from the highly under-sampled k-space data. In order to maximize the benefits of CS, it is obvious to use CS with the motion corrected samples...
October 13, 2016: Magnetic Resonance Imaging
Stephanie Preuss, Claudius Kuechle, Stefan Wagenpfeil, Christoph Schmaderer, Lutz Renders, Uwe Heemann, Konrad Stock
The aim of this retrospective single-center study was to examine ultrasound-detected complications after diagnostic parenchymal renal biopsies. After 471 ultrasound-guided kidney biopsies (225 native kidneys and 246 renal allografts), ultrasound revealed hematomas (21.9%), arterio-venous fistulas (8.9%), active bleeding (1.1%) and hematuria (0.4%). Only 0.8% of all patients required invasive intervention such as coiling (n = 3) and surgical procedures (n = 1). Three episodes of bleeding (0.6%) were solved with manual compression...
October 13, 2016: Ultrasound in Medicine & Biology
Pei T Mah, Dunja Novakovic, Jukka Saarinen, Stijn Van Landeghem, Leena Peltonen, Timo Laaksonen, Antti Isomäki, Clare J Strachan
PURPOSE: To investigate the effect of compression on the crystallization behavior in amorphous tablets using sum frequency generation (SFG) microscopy imaging and more established analytical methods. METHOD: Tablets containing neat amorphous griseofulvin with/without excipients (silica, hydroxypropyl methylcellulose acetate succinate (HPMCAS), microcrystalline cellulose (MCC) and polyethylene glycol (PEG)) were prepared. They were analyzed upon preparation and storage using attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, scanning electron microscopy (SEM) and SFG microscopy...
October 13, 2016: Pharmaceutical Research
Guilherme Teixeira Theodoro, Lívia Fiorin, Izabela Cristina Maurício Moris, Renata Cristina Silveira Rodrigues, Ricardo Faria Ribeiro, Adriana Cláudia Lapria Faria
Dental ceramics have been widely used because of aesthetic, but wear is still questioned. There are relates that ceramic surface is prone to degradation by acidulated fluoride, that can increase wear rates. The aim of this study was to evaluate the effect of neutral and acidulated fluoride gel, used as preventive agents for professional use, at wear and compression strength of dental ceramics IPS e.max ZirPress (ZIR), IPS Empress Esthetic (EMP) e IPS Inline POM (POM). For this, 30 crowns and 30 disks were obtained by heat-pressing...
September 28, 2016: Journal of the Mechanical Behavior of Biomedical Materials
M Cepeda, J A Mainez, B de la Cruz, J H Amón
The use of double J catheters is usual in urologist's daily practice. The indication can be divided in prophylactic or therapeutic. Prophylactically, they prevent complications derived from endourological procedures, such as ureteral lesion or obstructive uropathy secondary to residual lithiasis or edema. Therapeutically, they treat obstructive uropathy of many different pathologies, either in an emergency setting or scheduled, such as lithiasis, stenosis, extrinsic compression of any nature or urinary tract tumors among others...
October 2016: Archivos Españoles de Urología
Marina Salorio-Corbetto, Thomas Baer, Brian C J Moore
OBJECTIVE: The objective was to assess the degradation of speech sound quality produced by frequency compression for listeners with extensive high-frequency dead regions (DRs). DESIGN: Quality ratings were obtained using values of the starting frequency (Sf) of the frequency compression both below and above the estimated edge frequency, fe, of each DR. Thus, the value of Sf often fell below the lowest value currently used in clinical practice. Several compression ratios were used for each value of Sf...
October 11, 2016: International Journal of Audiology
Aditya B Singaraju, Kyle Nguyen, Abhay Jain, Rahul V Haware, Lewis L Stevens
The tableting performance for p-aminobenzoic acid (PABA) and a series of its benzoate esters with increasing alkyl chain length (methyl-, ethyl- and n-butyl) was determined over a broad range of compaction pressures. The crystalline structure of methyl benzoate (Me-PABA) exhibits no slip systems and does not form viable compacts under any compaction pressure. The ethyl (Et-PABA) and n-butyl (Bu-PABA) esters each have a similar, corrugated-layer structure that displays a prominent slip plane and improves material plasticity at low compaction pressure...
October 10, 2016: Molecular Pharmaceutics
Gabriel Aldaz, Sunil Puria, Larry J Leifer
BACKGROUND: Previous research has shown that hearing aid wearers can successfully self-train their instruments' gain-frequency response and compression parameters in everyday situations. Combining hearing aids with a smartphone introduces additional computing power, memory, and a graphical user interface that may enable greater setting personalization. To explore the benefits of self-training with a smartphone-based hearing system, a parameter space was chosen with four possible combinations of microphone mode (omnidirectional and directional) and noise reduction state (active and off)...
October 2016: Journal of the American Academy of Audiology
Tao Feng, David A Hoagland, Thomas P Russell
At appropriate conditions, water-dispersed acid-functionalized single-walled carbon nanotubes (SWCNTs) co-assemble at the oil/water interface with toluene-dissolved amine-terminated polystyrene (PS-NH2) to form composite thin films displaying pronounced interfacial viscoelasticity. To probe this viscoelasticity, the films were examined under dilatational deformations of pendant drop tensiometry/rheometry, with storage and loss moduli recorded against frequency ω (0.003 < ω < 3 Hz) and time-dependent relaxation modulus recorded against time t (0...
October 6, 2016: Soft Matter
S V Makarov, A N Tsypkin, T A Voytova, V A Milichko, I S Mukhin, A V Yulin, S E Putilin, M A Baranov, A E Krasnok, I A Morozov, P A Belov
The advantage of metasurfaces and nanostructures with a high nonlinear response is that they do not require phase matching, and the generated pulses are short in the time domain without additional pulse compression. However, the fabrication of large-scale planar structures by lithography-based methods is expensive, time consuming, and requires complicated preliminary simulations to obtain the most optimized geometry. Here, we propose a novel strategy for the self-assembled fabrication of large-scale resonant metasurfaces, where incident femtosecond laser pulses adjust the initial silicon films via specific surface deformation to be as resonant as possible for a given wavelength...
October 6, 2016: Nanoscale
Yuki Ichinoseki, Yoshio Machida
Our purpose in this study was to elucidate the relation between the one-dimensional (1D) and two-dimensional (2D) noise power spectra (NPSs) in magnetic resonance imaging (MRI). We measured the 1D NPSs using the slit method and the radial frequency method. In the slit method, numerical slits 1 pixel wide and L pixels long were placed on a noise image (128 × 128 pixels) and scanned in the MR image domain. We obtained the 1D NPS using the slit method (1D NPS_Slit) and the 2D NPS of the noise region scanned by the slit (2D NPS_Slit)...
October 3, 2016: Radiological Physics and Technology
Andrew D Brown, Francisco A Rodriguez, Cory D F Portnuff, Matthew J Goupell, Daniel J Tollin
In patients with bilateral hearing loss, the use of two hearing aids (HAs) offers the potential to restore the benefits of binaural hearing, including sound source localization and segregation. However, existing evidence suggests that bilateral HA users' access to binaural information, namely interaural time and level differences (ITDs and ILDs), can be compromised by device processing. Our objective was to characterize the nature and magnitude of binaural distortions caused by modern digital behind-the-ear HAs using a variety of stimuli and HA program settings...
October 3, 2016: Trends in Hearing
Kunio Yokoyama, Masahiro Kawanishi, Makoto Yamada, Hidekazu Tanaka, Yutaka Ito, Toshihiko Kuroiwa
As a treatment for painful vertebral compression fractures (VCFs), vertebral perforation does not require bone cement infusion. Here, we retrospectively assessed the long-term therapeutic effects of vertebroplasty in a comparison with those of vertebral perforation. The subjects were 64 patients who underwent percutaneous vertebroplasty (PVP group) and 67 patients who underwent vertebral perforation (Perforation group) between 2006 and 2011 at Takeda general hospital. We compared the analgesic effects of the treatments and the incidences of new VCFs between the groups at 15 months postsurgery...
October 4, 2016: British Journal of Neurosurgery
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