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Pulse sequence

J D Thiessen, E Shams, G Stortz, G Schellenberg, D Bishop, M S Khan, P Kozlowski, F Retière, V Sossi, C J Thompson, A L Goertzen
A full-ring PET insert consisting of 16 PET detector modules was designed and constructed to fit within the 114 mm diameter gradient bore of a Bruker 7 T MRI. The individual detector modules contain two silicon photomultiplier (SiPM) arrays, dual-layer offset LYSO crystal arrays, and high-definition multimedia interface (HDMI) cables for both signal and power transmission. Several different RF shielding configurations were assessed prior to construction of a fully assembled PET insert using a combination of carbon fibre and copper foil for RF shielding...
November 21, 2016: Physics in Medicine and Biology
Rosiane Yamasaki, Arlindo Montagnoli, Emi Z Murano, Eloisa Gebrim, Adriana Hachiya, Jorge Vicente Lopes da Silva, Mara Behlau, Domingos Tsuji
OBJECTIVE: To determine the impact of jitter and shimmer on the degree of naturalness perception of synthesized vowels produced by acoustical simulation with glottal pulses (GP) and with solid model of the vocal tract (SMVT). STUDY DESIGN: Prospective study. METHODS: Synthesized vowels were produced in three steps: 1. Eighty GP were developed (20 with jitter, 20 with shimmer, 20 with jitter+shimmer, 20 without perturbation); 2. A SMVT was produced based on magnetic resonance imaging (MRI) from a woman during phonation-/ε/ and using rapid prototyping technology; 3...
October 21, 2016: Journal of Voice: Official Journal of the Voice Foundation
Effat Soleimani, Manijhe Mokhtari-Dizaji, Nasser Fatouraee, Hazhir Saberi
Purpose: The aim of this study was to introduce and implement a noninvasive method to derive the carotid artery pressure waveform directly by processing diagnostic sonograms of the carotid artery. Methods: Ultrasound image sequences of 20 healthy male subjects (age, 36±9 years) were recorded during three cardiac cycles. The internal diameter and blood velocity waveforms were extracted from consecutive sonograms over the cardiac cycles by using custom analysis programs written in MATLAB...
September 20, 2016: Ultrasonography
Kang Liao, Yili Chen, Menghe Wang, Penghao Guo, Qiwen Yang, Yuxing Ni, Yunsong Yu, Bijie Hu, Ziyong Sun, Wenxiang Huang, Yong Wang, Anhua Wu, Xianju Feng, Yanping Luo, Zhidong Hu, Yunzhuo Chu, Shulan Chen, Bin Cao, Jianrong Su, Bingdong Gui, Qiong Duan, Shufang Zhang, Haifeng Shao, Haishen Kong, Yingchun Xu
BACKGROUND: Recently, the emergence of multidrug-resistant organisms such as extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae has raised considerable concern regarding the appropriate treatment of intra-abdominal infections (IAIs). In this study, we investigated the molecular characteristics of ESBL among clinical isolates of Escherichia coli and Klebsiella pneumoniae causing IAIs and their pattern of antimicrobial resistance, which can provide useful information about the epidemiology and risk factors associated with these infections...
October 7, 2016: Diagnostic Microbiology and Infectious Disease
Hong Shang, Subramaniam Sukumar, Cornelius von Morze, Robert A Bok, Irene Marco-Rius, Adam Kerr, Galen D Reed, Eugene Milshteyn, Michael A Ohliger, John Kurhanewicz, Peder E Z Larson, John M Pauly, Daniel B Vigneron
PURPOSE: Balanced steady-state free precession (bSSFP) sequences can provide superior signal-to-noise ratio efficiency for hyperpolarized (HP) carbon-13 ((13) C) magnetic resonance imaging by efficiently utilizing the nonrecoverable magnetization, but managing their spectral response is challenging in the context of metabolic imaging. A new spectrally selective bSSFP sequence was developed for fast imaging of multiple HP (13) C metabolites with high spatiotemporal resolution. THEORY AND METHODS: This novel approach for bSSFP spectral selectivity incorporates optimized short-duration spectrally selective radiofrequency pulses within a bSSFP pulse train and a carefully chosen repetition time to avoid banding artifacts...
October 21, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
R Rapini, A Cincinelli, G Marrazza
In this work, we propose an electrochemical DNA aptasensor for sensitive multidetection of acetamiprid based on a competitive format and disposable screen-printed arrays. To improve the sensitivity of the aptasensor, polyaniline film and gold nanoparticles were progressively electrodeposited on the graphite screen-printed electrode surface by cyclic voltammetry. Gold nanoparticles were then employed as platform for thiol-tethered DNA aptamer immobilization. Different acetamiprid solutions containing a fixed amount of biotinylated complementary oligonucleotide sequence by DNA aptasensor arrays were analyzed...
December 1, 2016: Talanta
Sungheon Gene Kim, Melanie Freed, Ana Paula Klautau Leite, Jin Zhang, Claudia Seuss, Linda Moy
PURPOSE: To assess the diagnostic utility of contrast kinetic analysis for breast lesions and background parenchyma of women undergoing MRI-guided biopsies, for whom standard clinical analysis had failed to separate benign and malignant lesions. MATERIALS AND METHODS: This study included 115 women who had indeterminate lesions based on routine diagnostic breast MRI exams and underwent an MRI (3 Tesla) -guided biopsy of one or more lesions suspicious for breast cancer...
October 20, 2016: Journal of Magnetic Resonance Imaging: JMRI
Jamil Abdolmohammadi, Mohsen Shafiee, Fariborz Faeghi, Douman Arefan, Alireza Zali, Rouzbeh Motiei-Langroudi, Zahra Farshidfar, Ali Kiani Nazarlou, Ali Tavakkoli, Mohammad Yarham
INTRODUCTION: Timely diagnosis of brain tumors could considerably affect the process of patient treatment. To do so, para-clinical methods, particularly MRI, cannot be ignored. MRI has so far answered significant questions regarding tumor characteristics, as well as helping neurosurgeons. In order to detect the tumor cellularity, neuro-surgeons currently have to sample specimens by biopsy and then send them to the pathology unit. The aim of this study is to determine the tumor cellularity in the brain...
August 2016: Electronic Physician
Robert R Edelman, Marcos Botelho, Amit Pursnani, Shivraman Giri, Ioannis Koktzoglou
BACKGROUND: Dark blood imaging of the heart is conventionally performed using a breath-hold, dual-inversion Cartesian fast spin-echo pulse sequence. Our aim was to develop a faster, more flexible approach that would be less motion-sensitive and provide better image quality. For this purpose, we implemented a prototype radial balanced steady-state free precession (bSSFP) pulse sequence. METHODS: The study was approved by the institutional review board. Six healthy volunteers and 27 subjects undergoing clinically-indicated cardiovascular magnetic resonance (CMR) were imaged using dark blood Cartesian fast spin-echo and radial bSSFP...
October 19, 2016: Journal of Cardiovascular Magnetic Resonance
Sven Haller, Greg Zaharchuk, David L Thomas, Karl-Olof Lovblad, Frederik Barkhof, Xavier Golay
Arterial spin labeling (ASL) is a magnetic resonance (MR) imaging technique used to assess cerebral blood flow noninvasively by magnetically labeling inflowing blood. In this article, the main labeling techniques, notably pulsed and pseudocontinuous ASL, as well as emerging clinical applications will be reviewed. In dementia, the pattern of hypoperfusion on ASL images closely matches the established patterns of hypometabolism on fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography (PET) images due to the close coupling of perfusion and metabolism in the brain...
November 2016: Radiology
H H Caline Koh-Tan, Mohammed Dashti, Ting Wang, Wendy Beattie, John Mcclure, Barbara Young, Anna F Dominiczak, Martin W Mcbride, Delyth Graham
BACKGROUND: We have previously confirmed the importance of rat chromosome 3 (RNO3) genetic loci on blood pressure elevation, pulse pressure (PP) variability and renal pathology during salt challenge in the stroke-prone spontaneously hypertensive (SHRSP) rat. The aims of this study were to generate a panel of RNO3 congenic sub-strains to genetically dissect the implicated loci and identify positional candidate genes by microarray expression profiling and analysis of next-generation sequencing data...
October 17, 2016: Journal of Hypertension
Farah Ben Tanfous, Carla Andrea Alonso, Wafa Achour, Laura Ruiz-Ripa, Carmen Torres, Assia Ben Hassen
The aim of this study was to investigate the molecular features among Klebsiella pneumoniae and Escherichia coli strains showing a resistant/intermediate-resistant phenotype to ertapenem (R/IR-ERT), implicated in colonization/infection in patients of the Hematology and Graft Units of the National Bone Marrow Transplant Center of Tunisia (3-year period, 2011-2014). The major carbapenemase, extended-spectrum beta-lactamase, and plasmidic AmpC beta-lactamase genes were analyzed and characterized by PCR and sequencing...
October 18, 2016: Microbial Drug Resistance: MDR: Mechanisms, Epidemiology, and Disease
Yancheng Yang, Zhen Hu, Weilong Shang, Qiwen Hu, Junmin Zhu, Jie Yang, Huagang Peng, Xiaopeng Zhang, Hui Liu, Yanguang Cong, Shu Li, Xiaomei Hu, Renjie Zhou, Xiancai Rao
Methicillin-susceptible Staphylococcus aureus (MSSA) accounts for ∼40% of staphylococcal infections in China. However, the molecular characterization of MSSA is not well described. In this study, 124 MSSA strains collected in 2013 from a comprehensive teaching hospital in Chongqing, Southwestern China, were subjected to antibiotics susceptibility testing and molecular typing, including multilocus sequence typing, staphylococcal protein A (spa) gene typing, accessory gene regulator (agr) typing, pulsed-field gel electrophoresis (PFGE) typing, Panton-Valentine leukocidin (pvl) gene detection, and antibiotic-resistant gene detection...
October 18, 2016: Microbial Drug Resistance: MDR: Mechanisms, Epidemiology, and Disease
C A Borges, L G Beraldo, R P Maluta, M V Cardozo, K B Barboza, E A L Guastalli, S Kariyawasam, C DebRoy, F A Ávila
Wild birds are carriers of Escherichia coli. However, little is known about their role as reservoirs for extra-intestinal pathogenic E. coli (ExPEC). In this work we investigated E. coli strains carrying virulence genes related to human and animal ExPEC isolated from free-living wild birds treated in a veterinary hospital. Multidrug resistance was found in 47.4% of the strains, but none of them were extended-spectrum beta-lactamase producers. Not only the virulence genes, but also the serogroups (e.g. O1 and O2) detected in the isolates of E...
October 18, 2016: Avian Pathology: Journal of the W.V.P.A
Yumiao Wei, Yonggui Dong, Xianxiang Huang, Zhili Zhang
In order to measure the nonlinear features of micromechanical resonators, a free damped oscillation method based on stair-stepped frequency sinusoidal pulse excitation is investigated. In the vicinity of the resonant frequency, a frequency stepping sinusoidal pulse sequence is employed as the excitation signal. A set of free vibration response signals, containing different degrees of nonlinear dynamical characteristics, are obtained. The amplitude-frequency curves of the resonator are acquired from the forced vibration signals...
October 13, 2016: Sensors
Michel E Safar
Mid-life elevated BP is classically associated with a raised systemic vascular resistance. A classical interpretation of the association between aortic stiffness and blood pressure (BP) invokes hypertension as a simple form of premature aging that increases stress on the arterial wall and accelerates age-related stiffening of the aorta. Recent clinical and experimental data have called into question the directionality of this sequence of events associating stiffness and hypertension.Therefore an initial abnormality in stiffness may antedate and contribute initially to the pathogenesis of hypertension, namely isolated systolic hypertension...
September 2016: Journal of Hypertension
Tomasz Wołkowicz, Jan Andrzej Patzer, Wanda Kamińska, Rafał Gierczyński, Danuta Dzierżanowska
This study aimed to analyse the distribution of carbapenem resistance mechanisms among Pseudomonas aeruginosa clinical isolates. Fifty-five P. aeruginosa isolates, resistant both to imipenem and meropenem, from children hospitalised in 2009-2010 were studied. All strains were genotyped by pulsed-field gel electrophoresis (PFGE). Mutations in the oprD gene and the occurrence of insertion sequences (ISs) were determined by DNA sequencing. Mex efflux systems were determined by analysis using the efflux pump inhibitor Phe-Arg β-naphthylamide...
October 8, 2016: Journal of Global Antimicrobial Resistance
Qiang Zhang, Nebojsa Stojanovic, Cristian Prodaniuc, Changsong Xie, Michael Koenigsmann, Piotr Laskowski
We experimentally demonstrate the generation and transmission of a single-lane 180  Gbit/s (90 GBaud) four-level pulse-amplitude modulation (PAM-4) signal in an intensity-modulation direct-detection system with a 7.5 GHz 3 dB bandwidth. The generated signal is transmitted over a 2 km standard single-mode fiber with, to the best of our knowledge, the highest reported net data rate in the C-band: 150  Gbit/s. A net data rate of 168  Gbit/s is also reachable with 1 km reach. The PAM-4 and duobinary (DB) PAM-4 modulation schemes are compared; the obtained results show that DB-PAM-4 significantly outperforms PAM-4 in the considered strong bandwidth-constrained system...
October 1, 2016: Optics Letters
Yong Yang, Hua Gu, Xiaofeng Yu, Li Zhan, Jiancai Chen, Yun Luo, Yunyi Zhang, Yanjun Zhang, Yiyu Lu, Jianmin Jiang, Lingling Mei
Emetic toxin producing Bacillus cereus (emetic B. cereus) is the third member of B. cereus group whose toxins are encoded by megaplasmids, beside anthrax and insecticidal toxins of B. anthracis and B. thuringiensis respectively. 18 emetic isolates collected from food poisoning events, clinical and non-random food samples in Zhejiang province of China, were analyzed by plasmid screening, pulse field gel electrophoresis (PFGE), multi-locus sequence typing (MLST), as well as toxic gene identification to investigate their genotypic diversity...
October 14, 2016: FEMS Microbiology Letters
V S Manu, Gianluigi Veglia
Identity operation in the form of π pulses is widely used in NMR spectroscopy. For an isolated single spin system, a sequence of even number of π pulses performs an identity operation, leaving the spin state essentially unaltered. For multi-spin systems, trains of π pulses with appropriate phases and time delays modulate the spin Hamiltonian to perform operations such as decoupling and recoupling. However, experimental imperfections often jeopardize the outcome, leading to severe losses in sensitivity. Here, we demonstrate that a newly designed Genetic Algorithm (GA) is able to optimize a train of π pulses, resulting in a robust identity operation...
September 27, 2016: Journal of Magnetic Resonance
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