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https://www.readbyqxmd.com/read/28437955/cyclic-coding-for-brillouin-optical-time-domain-analyzers-using-probe-dithering
#1
Haritz Iribas, Alayn Loayssa, Florian Sauser, Miguel Llera, Sébastien Le Floch
We study the performance limits of mono-color cyclic coding applied to Brillouin optical time-domain analysis (BOTDA) sensors that use probe wave dithering. BOTDA analyzers with dithering of the probe use a dual-probe-sideband setup in which an optical frequency modulation of the probe waves along the fiber is introduced. This avoids non-local effects while keeping the Brillouin threshold at its highest level, thus preventing the spontaneous Brillouin scattering from generating noise in the deployed sensing fiber...
April 17, 2017: Optics Express
https://www.readbyqxmd.com/read/28437230/high-diversity-of-antimicrobial-resistance-genes-class-1-integrons-and-genotypes-of-multidrug-resistant-escherichia-coli-in-beef-carcasses
#2
Chih-Ming Chen, Se-Chin Ke, Chia-Ru Li, Ying-Chen Wu, Ter-Hsin Chen, Chih-Ho Lai, Xin-Xia Wu, Lii-Tzu Wu
Multidrug-resistant Escherichia coli can contaminate food meat during processing and cause human infection. Phenotypic and genotypic characterization of the antimicrobial resistance were conducted for 45 multidrug-resistant E. coli isolates from 208 samples of beef carcasses. The mechanisms of resistance were evaluated using polymerase chain reaction and sequencing methods, and the clonal relationship among isolates was evaluated using multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE)...
February 23, 2017: Microbial Drug Resistance: MDR: Mechanisms, Epidemiology, and Disease
https://www.readbyqxmd.com/read/28437228/first-case-of-ndm-1-producing-klebsiella-pneumoniae-in-annaba-university-hospital-algeria
#3
Amel Abderrahim, Nassima Djahmi, Charlotte Pujol, Sabina Nedjai, Mohamed Cherif Bentakouk, Djamila Kirane-Gacemi, Mazouz Dekhil, Albert Sotto, Jean-Philippe Lavigne, Alix Pantel
AIM: The aim of this study was to characterize two carbapenem-resistant Klebsiella pneumoniae isolates recovered from urine samples in a patient hospitalized at Annaba University hospital (Algeria) in 2014. RESULTS: Two K. pneumoniae isolates were studied because they proved resistant to almost all antibiotics tested with a high level resistance to ertapenem (minimum inhibitory concentration = 32 mg/L). The results of modified Hodge test and combined disk test (ROSCO Diagnostica, Taastrup, Denmark) were positive...
February 22, 2017: Microbial Drug Resistance: MDR: Mechanisms, Epidemiology, and Disease
https://www.readbyqxmd.com/read/28435103/magnetization-transfer-contrast-and-chemical-exchange-saturation-transfer-mri-features-and-analysis-of-the-field-dependent-saturation-spectrum
#4
Peter C M van Zijl, Wilfred W Lam, Jiadi Xu, Linda Knutsson, Greg J Stanisz
Magnetization Transfer Contrast (MTC) and Chemical Exchange Saturation Transfer (CEST) experiments measure the transfer of magnetization from molecular protons to the solvent water protons, an effect that becomes apparent as an MRI signal loss ("saturation"). This allows molecular information to be accessed with the enhanced sensitivity of MRI. In analogy to Magnetic Resonance Spectroscopy (MRS), these saturation data are presented as a function of the chemical shift of participating proton groups, e.g. OH, NH, NH2, which is called a Z-spectrum...
April 20, 2017: NeuroImage
https://www.readbyqxmd.com/read/28433011/ramped-amplitude-novel
#5
T V Can, R T Weber, J J Walish, T M Swager, R G Griffin
We present a pulsed dynamic nuclear polarization (DNP) study using a ramped-amplitude nuclear orientation via electron spin locking (RA-NOVEL) sequence that utilizes a fast arbitrary waveform generator (AWG) to modulate the microwave pulses together with samples doped with narrow-line radicals such as 1,3-bisdiphenylene-2-phenylallyl (BDPA), sulfonated-BDPA (SA-BDPA), and trityl-OX063. Similar to ramped-amplitude cross polarization in solid-state nuclear magnetic resonance, RA-NOVEL improves the DNP efficiency by a factor of up to 1...
April 21, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28432504/3t-mri-of-the-knee-with-optimised-isotropic-3d-sequences-accurate-delineation-of-intra-articular-pathology-without-prolonged-acquisition-times
#6
Osamah M Abdulaal, Louise Rainford, Peter MacMahon, Eoin Kavanagh, Marie Galligan, James Cashman, Allison McGee
OBJECTIVES: To investigate optimised isotropic 3D turbo spin echo (TSE) and gradient echo (GRE)-based pulse sequences for visualisation of articular cartilage lesions within the knee joint. METHODS: Optimisation of experimental imaging sequences was completed using healthy volunteers (n=16) with a 3-Tesla (3T) MRI scanner. Imaging of patients with knee cartilage abnormalities (n=57) was then performed. Acquired sequences included 3D proton density-weighted (PDW) TSE (SPACE) with and without fat-suppression (FS), and T2*W GRE (TrueFISP) sequences, with acquisition times of 6:51, 6:32 and 5:35 min, respectively...
April 21, 2017: European Radiology
https://www.readbyqxmd.com/read/28430716/simultaneous-multislice-accelerated-turbo-spin-echo-magnetic-resonance-imaging-comparison-and-combination-with-in-plane-parallel-imaging-acceleration-for-high-resolution-magnetic-resonance-imaging-of-the-knee
#7
Jan Fritz, Benjamin Fritz, Jialu Zhang, Gaurav K Thawait, Dharmdev H Joshi, Li Pan, Dingxin Wang
PURPOSE: We prospectively quantified the signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of integrated parallel acquisition technique (PAT) and simultaneous multislice (SMS) acceleration and various combinations thereof, and we further compared two 4-fold-accelerated (PAT2-SMS2) high-resolution turbo spin echo (TSE) magnetic resonance imaging (MRI) protocols of the knee against a clinical 2-fold-accelerated (PAT2-SMS1) TSE standard. MATERIALS AND METHODS: Institutional review board approval was obtained, and all subjects gave informed consent...
April 20, 2017: Investigative Radiology
https://www.readbyqxmd.com/read/28428772/molecular-characterization-of-staphylococcus-aureus-isolated-from-bovine-mastitis-and-close-human-contacts-in-south-african-dairy-herds-genetic-diversity-and-inter-species-host-transmission
#8
Tracy Schmidt, Marleen M Kock, Marthie M Ehlers
Staphylococcus aureus is one of the most common etiological agents of contagious bovine mastitis worldwide. The purpose of this study was to genetically characterize a collection of S. aureus isolates (bovine = 146, human = 12) recovered from cases of bovine mastitis and nasal swabs of close human contacts in the dairy environment. Isolates were screened for a combination of clinically significant antimicrobial and virulence gene markers whilst the molecular epidemiology of these isolates and possible inter-species host transmission was investigated using a combination of genotyping techniques...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28428213/clinically-feasible-microstructural-mri-to-quantify-cervical-spinal-cord-tissue-injury-using-dti-mt-and-t2-weighted-imaging-assessment-of-normative-data-and-reliability
#9
A R Martin, B De Leener, J Cohen-Adad, D W Cadotte, S Kalsi-Ryan, S F Lange, L Tetreault, A Nouri, A Crawley, D J Mikulis, H Ginsberg, M G Fehlings
BACKGROUND AND PURPOSE: DTI, magnetization transfer, T2*-weighted imaging, and cross-sectional area can quantify aspects of spinal cord microstructure. However, clinical adoption remains elusive due to complex acquisitions, cumbersome analysis, limited reliability, and wide ranges of normal values. We propose a simple multiparametric protocol with automated analysis and report normative data, analysis of confounding variables, and reliability. MATERIALS AND METHODS: Forty healthy subjects underwent T2WI, DTI, magnetization transfer, and T2*WI at 3T in <35 minutes using standard hardware and pulse sequences...
April 20, 2017: AJNR. American Journal of Neuroradiology
https://www.readbyqxmd.com/read/28427842/predominance-of-international-clone-2-oxa-23-producing-acinetobacter-baumannii-clinical-isolates-in-greece-2015-results-of-a-nationwide-study
#10
Spyros Pournaras, Konstantina Dafopoulou, Mariateresa Del Franco, Olympia Zarkotou, Evangelia Dimitroulia, Efi Protonotariou, Aggeliki Poulou, Raffaele Zarrilli, Athanasios Tsakris
In a previous nationwide study in Greece, OXA-58 was the sole carbapenemase present among carbapenem-resistant Acinetobacter baumannii (CRAB) isolated between 2000 and 2009. In this study, the antibiotic resistances, carbapenemase gene content and clonal relatedness of 194 single-patient CRAB clinical isolates collected randomly during 2015 from 11 tertiary hospitals located throughout Greece were investigated. Antimicrobial susceptibility was determined using commercial and dilution methods. PCR for carbapenemase genes were performed...
April 18, 2017: International Journal of Antimicrobial Agents
https://www.readbyqxmd.com/read/28420970/single-session-anodal-tdcs-with-small-size-stimulating-electrodes-over-frontoparietal-superficial-sites-does-not-affect-motor-sequence-learning
#11
Fahimeh Hashemirad, Paul B Fitzgerald, Maryam Zoghi, Shapour Jaberzadeh
Due to the potential of anodal transcranial direct current stimulation (a-tDCS) for enhancement of fine sequenced movements and increasing interest in achieving high level of fine movements in the trained and untrained hands especially at initial stage of learning, we designed this study to investigate whether the application of single-session a-tDCS with small-size stimulating electrodes over FPN sites, such as dorsolateral prefrontal cortex (DLPFC), primary motor cortex (M1) or posterior parietal cortex (PPC) could enhance sequence learning with the trained hand and these effects are transferred into the untrained hand or not...
2017: Frontiers in Human Neuroscience
https://www.readbyqxmd.com/read/28419869/allodemic-distribution-of-plasmids-co-harbouring-blactx-m-15-aac-6-ib-cr-qnrb-in-klebsiella-pneumoniae-is-the-main-source-of-extended-spectrum-%C3%AE-lactamases-in-uruguay-s-paediatric-hospital
#12
V Garcia-Fulgueiras, L Araujo, I Bado, N F Cordeiro, M I Mota, G Laguna, G Algorta, R Vignoli
OBJECTIVES: This study aimed to describe the characteristics of clinical isolates of extended-spectrum β-lactamase (ESBL)-producing enterobacteria (EPE) in Uruguay's paediatric hospital. METHODS: ESBLs, qnr alleles and aac(6')-Ib-cr were sought and characterised in EPE isolated between March 2010 and March 2012. Transfer of resistance determinants was assessed by conjugation. Incompatibility (Inc) groups, plasmid toxin-antitoxin systems (TAS) and plasmid size were determined in transconjugants...
April 15, 2017: Journal of Global Antimicrobial Resistance
https://www.readbyqxmd.com/read/28419602/physics-for-clinicians-fluid-attenuated-inversion-recovery-flair-and-double-inversion-recovery-dir-imaging
#13
REVIEW
Manojkumar Saranathan, Pauline W Worters, Dan W Rettmann, Blair Winegar, Jennifer Becker
A pedagogical review of fluid-attenuated inversion recovery (FLAIR) and double inversion recovery (DIR) imaging is conducted in this article. The basics of the two pulse sequences are first described, including the details of the inversion preparation and imaging sequences with accompanying mathematical formulae for choosing the inversion time in a variety of scenarios for use on clinical MRI scanners. Magnetization preparation (or T2prep), a strategy for improving image signal-to-noise ratio and contrast and reducing T1 weighting at high field strengths, is also described...
April 17, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28419591/application-of-spin-echoes-in-the-regime-of-weak-dephasing-to-t1-mapping-of-the-lung
#14
Jakob Assländer, Steffen J Glaser, Jürgen Hennig
PURPOSE: This work presents an approach to mapping the entire lung's proton density and T1 within a single breath-hold and analyzes the apparent T1 when exciting with a spin echo generating pulse in comparison to a standard gradient echo acquisition. METHODS: An inversion-recovery SNAPSHOT-FLASH sequence with a stack-of-stars k-space readout with a golden angle increment was modified to use a spin echo generating radiofrequency-pulse for excitation. Data of five volunteers were acquired on a 3T scanner and image reconstruction was performed by an iterative algorithm adopted from MR-Fingerprinting...
April 17, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28414572/molecular-characterization-of-fluoroquinolone-resistant-haemophilus-parainfluenzae-clinical-isolates-in-spain
#15
Inmaculada López-Hernández, Jesús Machuca, Paula Díaz de Alba, Carolina Sarvisé, Frederic Gómez, José Manuel Rodríguez-Martínez, Alvaro Pascual
OBJECTIVE: The objective was to characterize a group of clinical isolates of fluoroquinolone-resistant Haemophilus parainfluenzae collected in Northern Spain (March-December 2014). METHODS: Twelve clinical isolates of H. parainfluenzae were studied by performing antimicrobial susceptibility testing and PCR amplification and nucleotide sequencing of the QRDR (quinolone resistance-determining region) of gyrA, parC, gyrB, and parE genes. Screening for plasmid-mediated quinolone resistance (PMQR) was also studied...
April 17, 2017: Microbial Drug Resistance: MDR: Mechanisms, Epidemiology, and Disease
https://www.readbyqxmd.com/read/28412740/combination-epidermal-growth-factor-receptor-variant-iii-peptide-pulsed-dendritic-cell-vaccine-with-mir-326-results-in-enhanced-killing-on-egfrviii-positive-cells
#16
Jianlong Li, Feng Wang, Guangzhi Wang, Ying Sun, Jinquan Cai, Xing Liu, Junhe Zhang, Xiaoyan Lu, Yongli Li, Meng Chen, Lingchao Chen, Chuanlu Jiang
The mutant Type III variant of epidermal growth factor receptor (EGFRvIII) is present in approximately one-third of glioblastoma (GBM) patients. It is never found in normal tissues; therefore, it represents a candidate target for GBM immunotherapy. PEPvIII, a peptide sequence from EGFRvIII, was designed to represent a target of glioma and is presented by MHC I/II complexes. Dendritic cells (DCs) have great potential to sensitize CD4+ T and CD8+ T cells to precisely target and eradicate GBM. Here, we show that PEPvIII could be loaded by DCs and presented to T lymphocytes, especially PEPvIII-specific CTLs, to precisely kill U87-EGFRvIII cells...
February 17, 2017: Oncotarget
https://www.readbyqxmd.com/read/28412455/effects-of-rf-pulse-profile-and-intra-voxel-phase-dispersion-on-mr-fingerprinting-with-balanced-ssfp-readout
#17
Su-Chin Chiu, Te-Ming Lin, Jyh-Miin Lin, Hsiao-Wen Chung, Cheng-Wen Ko, Martin Büchert, Michael Bock
PURPOSE: To investigate possible errors in T1 and T2 quantification via MR fingerprinting with balanced steady-state free precession readout in the presence of intra-voxel phase dispersion and RF pulse profile imperfections, using computer simulations based on Bloch equations. MATERIALS AND METHODS: A pulse sequence with TR changing in a Perlin noise pattern and a nearly sinusoidal pattern of flip angle following an initial 180-degree inversion pulse was employed...
April 13, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28409988/control-of-spatial-correlations-between-rydberg-excitations-using-rotary-echo
#18
N Thaicharoen, A Schwarzkopf, G Raithel
We manipulate correlations between Rydberg excitations in cold atom samples using a rotary-echo technique in which the phase of the excitation pulse is flipped at a selected time during the pulse. The correlations are due to interactions between the Rydberg atoms. We measure the resulting change in the spatial pair correlation function of the excitations via direct position-sensitive atom imaging. For zero detuning of the lasers from the interaction-free Rydberg-excitation resonance, the pair-correlation value at the most likely nearest-neighbor Rydberg-atom distance is substantially enhanced when the phase is flipped at the middle of the excitation pulse...
March 31, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28409941/arbitrarily-accurate-pulse-sequences-for-robust-dynamical-decoupling
#19
Genko T Genov, Daniel Schraft, Nikolay V Vitanov, Thomas Halfmann
We introduce universally robust sequences for dynamical decoupling, which simultaneously compensate pulse imperfections and the detrimental effect of a dephasing environment to an arbitrary order, work with any pulse shape, and improve performance for any initial condition. Moreover, the number of pulses in a sequence grows only linearly with the order of error compensation. Our sequences outperform the state-of-the-art robust sequences for dynamical decoupling. Beyond the theoretical proposal, we also present convincing experimental data for dynamical decoupling of atomic coherences in a solid-state optical memory...
March 31, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28409253/review-of-key-concepts-in-magnetic-resonance-physics
#20
REVIEW
Michael M Moore, Taylor Chung
MR physics can be a challenging subject for practicing pediatric radiologists. Although many excellent texts provide very comprehensive reviews of the field of MR physics at various levels of understanding, the authors of this paper explain several key concepts in MR physics that are germane to clinical practice in a non-rigorous but practical fashion. With the basic understanding of these key concepts, practicing pediatric radiologists can build on their knowledge of current clinical MR techniques and future advances in MR applications...
May 2017: Pediatric Radiology
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