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Daniella Klebaner, Stephen Hamilton-Dutoit, Thomas Ahern, Anatasha Crawford, Thomas Jakobsen, Deirdre P Cronin-Fenton, Per Damkier, Emiel Janssen, Anders Kjaersgaard, Anne Gulbech Ording, Håvard Søiland, Henrik Toft Sørensen, Timothy L Lash, Ylva Hellberg
BACKGROUND: Apolipoprotein D (ApoD) has been proposed as a predictor of breast cancer recurrence among estrogen receptor-positive (ER+), tamoxifen-treated patients. METHODS: We conducted a population-based case-control study nested in a population of 11,251 women aged 35-69 years at diagnosis with Stage I-III breast cancer between 1985 and 2001 on Denmark's Jutland Peninsula and registered with the Danish Breast Cancer Cooperative Group. We identified 541 recurrent or contralateral breast cancers cases among women with ER+ disease treated with tamoxifen for at least 1 year and 300 cases in women with ER- disease never treated with tamoxifen...
2017: PloS One
Kali Prasanna Nayak, Jameesh Keloth, Kohzo Hakuta
We present a protocol for fabricating 1-D Photonic Crystal (PhC) cavities on subwavelength-diameter tapered optical fibers, optical nanofibers, using femtosecond laser-induced ablation. We show that thousands of periodic nano-craters are fabricated on an optical nanofiber by irradiating with just a single femtosecond laser pulse. For a typical sample, periodic nano-craters with a period of 350 nm and with diameter gradually varying from 50 - 250 nm over a length of 1 mm are fabricated on a nanofiber with diameter around 450 - 550 nm...
February 25, 2017: Journal of Visualized Experiments: JoVE
Raquel Pascua-Maestro, Sergio Diez-Hermano, Concepción Lillo, Maria D Ganfornina, Diego Sanchez
Environmental insults such as oxidative stress can damage cell membranes. Lysosomes are particularly sensitive to membrane permeabilization since their function depends on intraluminal acidic pH and requires stable membrane-dependent proton gradients. Among the catalog of oxidative stress-responsive genes is the Lipocalin Apolipoprotein D (ApoD), an extracellular lipid binding protein endowed with antioxidant capacity. Within the nervous system, cell types in the defense frontline, such as astrocytes, secrete ApoD to help neurons cope with the challenge...
February 2017: PLoS Genetics
Junseob Shin, Yu Chen, Harshawn Malhi, Jesse Yen
Despite numerous recent advances in medical ultrasound imaging, reverberation clutter from near-field anatomical structures, such as the abdominal wall, ribs, and tissue layers, is one of the major sources of ultrasound image quality degradation. Reverberation clutter signals are undesirable echoes, which arise as a result of multiple reflections of acoustic waves between the boundaries of these structures, and cause fill-in to lower image contrast. In order to mitigate the undesirable reverberation clutter effects, we present in this paper a new beamforming technique called multi-phase apodization with cross-correlation (MPAX), which is an improved version of our previous technique, DAX...
August 2, 2016: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
Giulia Matrone, Alessandro Ramalli, Alessandro Savoia, Piero Tortoli, Giovanni Magenes
Multi-Line Transmission (MLT) was recently demonstrated as a valuable tool to increase the frame rate of ultrasound images. In this approach, the multiple beams that are simultaneously transmitted may determine cross-talk artifacts that are typically reduced, although not eliminated, by the use of Tukey apodization on both transmission and reception apertures, which unfortunately worsens the image lateral resolution. In this paper we investigate the combination, and related performance, of Filtered-Delay Multiply And Sum (F-DMAS) beamforming with MLT for high frame-rate ultrasound imaging...
October 4, 2016: IEEE Transactions on Medical Imaging
Pascal Ramaekers, Mario Ries, Chrit T W Moonen, Martijn de Greef
PURPOSE: A major complication for abdominal High Intensity Focused Ultrasound (HIFU) applications is the obstruction of the acoustic beam path by the thoracic cage, which absorbs and reflects the ultrasonic energy leading to undesired overheating of healthy tissues in the pre-focal area. Prior work has investigated the determination of optimized transducer apodization laws, which allow for a reduced rib exposure whilst (partially) restoring focal point intensity through power compensation...
January 6, 2017: Medical Physics
A Shankar, M Russ, S Vijayan, D Bednarek, S Rudin
PURPOSE: Signal and noise aliasing are major issues with high resolution direct and indirect detectors for which the Apodized Aperture Pixel (AAP) design provides an alternative solution. METHODS: High resolution detectors for neurovascular interventions have MTFs that remain significant even at the Nyquist frequency. Under-sampling in such detectors, leads to aliasing of object frequencies and noise. Frequencies above the Nyquist wrap into the lower frequency range leading to aliasing...
June 2016: Medical Physics
Amir Gholampour, Sayed Mahmoud Sakhaei, Seyed Mehdi Hosseini Andargoli
Apodization is a common way to control the sidelobe level of the beampattern. To design the apodization, it is usually assumed that the medium is homogenous with a fixed value of sound speed, despite the fact that the speed may vary by a great value in practical situations. On the other hand, the beamforming performance is highly affected by the speed value. In this paper, the beampattern sensitivity to the speed variations is firstly investigated through both mathematical representations and simulation results showing that the speed errors lead to a sever degradation of the beampattern in terms of both mainlobe width and sidelobe level...
December 16, 2016: Ultrasonics
Adela Brahimaj, Symen Ligthart, M Arfan Ikram, Albert Hofman, Oscar H Franco, Eric J G Sijbrands, Maryam Kavousi, Abbas Dehghan
OBJECTIVE: We aimed to investigate the role of serum levels of various apolipoproteins on the risk for type 2 diabetes (T2D). RESEARCH DESIGN AND METHODS: We used data from 971 individuals from the prospective population-based Rotterdam Study. We studied the association of HDL cholesterol (HDL-C), apoA1, apoCIII, apoD, and apoE as well as the ratios of apolipoproteins with apoA1 with the risk of T2D. All apolipoproteins, ratios, and HDL-C levels were naturally log-transformed to reach normal distribution...
March 2017: Diabetes Care
Jing Liu, Qiong He, Jianwen Luo
A novel beamforming technique, named compressed sensing based synthetic transmit aperture (CS-STA) is proposed to speed up the acquisition of ultrasound imaging. This technique consists of three steps. First, the ultrasound transducer transmits randomly apodized plane waves for a number of times and receives the backscattered echoes. Second, the recorded backscattered echoes are used to recover the full channel dataset of synthetic transmit aperture (STA) with a compressed sensing (CS) reconstruction algorithm...
December 23, 2016: IEEE Transactions on Medical Imaging
Krishna P Khakurel, Takashi Kimura, Hiroki Nakamori, Takumi Goto, Satoshi Matsuyama, Tomoya Sasaki, Masashi Takei, Yoshiki Kohmura, Tetsuya Ishikawa, Kazuto Yamauchi, Yoshinori Nishino
X-ray science has greatly benefited from the progress in X-ray optics. Advances in the design and the manufacturing techniques of X-ray optics are key to the success of various microscopic and spectroscopic techniques practiced today. Here the generation of apodized X-ray illumination using a two-stage deformable Kirkpatrick-Baez mirror system is presented. Such apodized illumination is marked by the suppression of the side-lobe intensities of the focused beam. Thus generated apodized illumination was employed to improve the image quality in scanning X-ray fluorescence microscopy...
January 1, 2017: Journal of Synchrotron Radiation
A S Shcherbakov, A O Arellanes, V Chavushyan
We develop an advanced approach to the optical spectrometer with acousto-optical dynamic grating for the Guillermo Haro astrophysical observatory (Mexico). The progress consists of two principle novelties. First is the use of the acousto-optical nonlinearity of two-phonon light scattering in crystals with linear acoustic losses. This advanced regime of light scattering exhibits a recently revealed additional degree of freedom, which allows tuning of the frequency of elastic waves and admits the nonlinear apodization improving the dynamic range...
December 1, 2016: Applied Optics
Megan Ulmer Carnes, R Rand Allingham, Allison Ashley-Koch, Michael A Hauser
PURPOSE: To characterize the transcriptional landscape of human adult and fetal trabecular meshwork (TM), cornea, and ciliary body (CB) tissues, and to evaluate the expression level of candidate genes selected from genetic association studies of primary-open angle glaucoma, central corneal thickness, intraocular pressure, vertical cup to disc ratio, and optic nerve parameters. METHODS: Deep RNA sequencing was performed on the selected human tissues. Transcriptome analyses were performed to 1) characterize the total number of expressed genes, 2) identify the most highly expressed genes, 3) estimate the number of novel transcripts, and 4) evaluate the expression of candidate genes in each tissue...
November 30, 2016: Experimental Eye Research
Minjie Wu, Liang Fang, Charles E Ray, Anand Kumar, Shaolin Yang
PURPOSE: A method for adaptively optimized combination (AOC) of MR spectroscopic data from a coil array was recently introduced. The superior performance of the AOC method is evident when compared with the methods that assume uncorrelated noise between coil elements. However, it is unclear whether the AOC method represents the most optimal combination in the presence of correlated noise, when compared with the noise-decorrelated or whitened methods that specifically tackle the correlated noise between coil elements...
November 21, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
Victor Perez, Bo-Jui Chang, Ernst Hans Karl Stelzer
Structured illumination microscopy relies on reconstruction algorithms to yield super-resolution images. Artifacts can arise in the reconstruction and affect the image quality. Current reconstruction methods involve a parametrized apodization function and a Wiener filter. Empirically tuning the parameters in these functions can minimize artifacts, but such an approach is subjective and produces volatile results. We present a robust and objective method that yields optimal results by two straightforward filtering steps with Richardson-Lucy-based deconvolutions...
November 16, 2016: Scientific Reports
Parinaz Aleahmad, Hector Moya Cessa, Ido Kaminer, Mordechai Segev, Demetrios N Christodoulides
We investigate the propagation dynamics of accelerating beams that are shape-preserving solutions of the Maxwell equations, and explore the contribution of their evanescent field components in detail. Both apodized and nonapodized Bessel beam configurations are considered. We show that, in spite of the fact that their evanescent tails do not propagate, these nonparaxial beams can still accelerate along circular trajectories and can exhibit large deflections. Subsequently, our formulation is extended in other two-dimensional vectorial arrangements...
October 1, 2016: Journal of the Optical Society of America. A, Optics, Image Science, and Vision
Junseob Shin, Yu Chen, Harshawn Malhi, Jesse T Yen
Despite numerous recent advances in medical ultrasound imaging, reverberation clutter from near-field anatomical structures, such as the abdominal wall, ribs, and tissue layers, is one of the major sources of ultrasound image quality degradation. Reverberation clutter signals are undesirable echoes, which arise as a result of multiple reflections of acoustic waves between the boundaries of these structures, and cause fill-in to lower image contrast. In order to mitigate the undesirable reverberation clutter effects, we present, in this paper, a new beamforming technique called multiphase apodization with cross correlation (MPAX), which is an improved version of our previous technique, dual apodization with cross correlation (DAX)...
November 2016: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
Simon Holbek, Thomas Lehrmann Christiansen, Matthias Bo Stuart, Christopher Beers, Erik Vilain Thomsen, Jorgen Arendt Jensen
Simulation and experimental results from 3-D vector flow estimations for a 62 + 62 2-D row-column (RC) array with integrated apodization are presented. A method for implementing a 3-D transverse oscillation (TO) velocity estimator on a 3-MHz RC array is developed and validated. First, a parametric simulation study is conducted, where flow direction, ensemble length, number of pulse cycles, steering angles, transmit/receive apodization, and TO apodization profiles and spacing are varied, to find the optimal parameter configuration...
November 2016: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
Yang Chen, Robert Halir, Íñigo Molina-Fernández, Pavel Cheben, Jian-Jun He
Chip-fiber grating couplers have been widely used in silicon-on-insulator platforms. In silicon nitride waveguides, the lower index contrast yields gratings with a weaker radiation strength and poor directionality, thereby limiting the coupling efficiency. Here we propose and design an apodized self-imaging grating coupler in silicon nitride that images an in-plane waveguide input to an output optical fiber placed at a specific distance above the chip. Both amplitude and phase apodizations are employed to engineer the transfer function of the self-imaging grating to produce an image field matching the fiber mode profile...
November 1, 2016: Optics Letters
Hamed Pishvai Bazargani, Maurizio Burla, Lukas Chrostowski, José Azaña
We experimentally demonstrate high-performance integer and fractional-order photonic Hilbert transformers based on laterally apodized Bragg gratings in a silicon-on-insulator technology platform. The sub-millimeter-long gratings have been fabricated using single-etch electron beam lithography, and the resulting HT devices offer operation bandwidths approaching the THz range, with time-bandwidth products between 10 and 20.
November 1, 2016: Optics Letters
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