keyword
MENU ▼
Read by QxMD icon Read
search

Pulse sequence

keyword
https://www.readbyqxmd.com/read/28107690/time-domain-nmr-as-a-new-process-monitoring-method-for-characterization-of-pharmaceutical-hydrates
#1
Stefanie Ulrike Schumacher, Benno Rothenhäusler, Alf Willmann, Jürgen Thun, Regina Moog, Martin Kuentz
Hydrates are of great pharmaceutical relevance and even though they have been characterized thoroughly by various analytical techniques, there is barely literature available on molecular mobility of the hydrate water studied by NMR relaxation in the time domain. The aim of this work was to examine the possibility of differentiating hydration states of drugs by (1)H time domain NMR (TD-NMR) regarding spin-spin and spin-lattice relaxation times (T2 and T1) using benchtop equipment. Caffeine and theophylline were selected as model compounds and binary mixtures of hydrate to anhydrate were analyzed for each drug using a spin echo and inversion recovery pulse sequence...
January 9, 2017: Journal of Pharmaceutical and Biomedical Analysis
https://www.readbyqxmd.com/read/28104504/diversity-of-new-delhi-metallo-beta-lactamase-producing-bacteria-in-china
#2
Xiaofeng Hu, Xuebing Xu, Xu Wang, Wencheng Xue, Haijian Zhou, Ling Zhang, Qiuxia Ma, Rongtao Zhao, Guozheng Li, Peng Li, Chuanfu Zhang, Yun Shi, Jian Wang, Leili Jia, Rongzhang Hao, Ligui Wang, Dayang Zou, Xuelin Liu, Shaofu Qiu, Hongbin Song, Yansong Sun
OBJECTIVES: The prevalence and dissemination of diverse NDM-producing bacteria in China was investigated. METHODS: We collected 1,162 isolates from 8 cities during December 2013∼May 2015 in China. The NDM-positive strains as well as the NDM genotypes in these sample were detected via Vitek 2 compact system (bioMérieux, France), 16S rRNA gene sequencing, PCR and an S1- pulsed-field gel electrophoresis assay and Southern blot hybridization. The horizontal-transfer capability of the blaNDM gene was assessed by filter mating by using a standard E...
January 16, 2017: International Journal of Infectious Diseases: IJID
https://www.readbyqxmd.com/read/28102949/simultaneous-pet-mr-imaging-with-a-radio-frequency-penetrable-pet-insert
#3
Alexander M Grant, Brian J Lee, Chen-Ming Chang, Craig S Levin
PURPOSE: A brain sized radio frequency (RF)-penetrable PET insert has been designed for simultaneous operation with MRI systems. This system takes advantage of electro-optical coupling and battery power to electrically float the PET insert relative to the MRI ground, permitting RF signals to be transmitted through small gaps between the modules that form the PET ring. This design facilitates the use of the built-in body coil for RF transmission and thus could be inserted into any existing MR site wishing to achieve simultaneous PET/MR imaging...
January 2017: Medical Physics
https://www.readbyqxmd.com/read/28099500/genetic-analysis-of-vibrio-parahaemolyticus-o3-k6-strains-that-have-been-isolated-in-mexico-since-1998
#4
Abraham Guerrero, Marcial Leonardo Lizárraga-Partida, Bruno Gómez Gil Rodríguez, Alexei Fedorovish Licea-Navarro, Valeria Jeanette Revilla-Castellanos, Irma Wong-Chang, Ricardo González-Sánchez
Vibrio parahaemolyticus is an important human pathogen that has been isolated worldwide from clinical cases, most of which have been associated with seafood consumption. Environmental and clinical toxigenic strains of V. parahaemolyticus that were isolated in Mexico from 1998 to 2012, including those from the only outbreak that has been reported in this country, were characterized genetically to assess the presence of the O3:K6 pandemic clone, and their genetic relationship to strains that are related to the pandemic clonal complex (CC3)...
2017: PloS One
https://www.readbyqxmd.com/read/28097749/positive-contrast-from-cells-labeled-with-iron-oxide-nanoparticles-quantitation-of-imaging-data
#5
Sergey Magnitsky, Jinjin Zhang, Djaudat Idiyatullin, Geetha Mohan, Michael Garwood, Nancy E Lane, Sharmila Majumdar
PURPOSE: Conventional T2 -weighted MRI produces a hypointense signal from iron-labeled cells, which renders quantification unfeasible. We tested a SWeep Imaging with Fourier Transformation (SWIFT) MRI pulse sequence to generate a quantifiable hyperintense signal from iron-labeled cells. METHODS: Mesenchymal stem cells (MSCs) were labeled with different concentrations of iron oxide particles and examined for cell viability, proliferation, and differentiation. The SWIFT sequence was optimized to detect and quantify the amount of iron in the muscle tissue after injection of iron oxide solution and iron-labeled MSCs...
January 17, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28094255/specific-and-sensitive-isothermal-electrochemical-biosensor-for-plant-pathogen-dna-detection-with-colloidal-gold-nanoparticles-as-probes
#6
Han Yih Lau, Haoqi Wu, Eugene J H Wee, Matt Trau, Yuling Wang, Jose R Botella
Developing quick and sensitive molecular diagnostics for plant pathogen detection is challenging. Herein, a nanoparticle based electrochemical biosensor was developed for rapid and sensitive detection of plant pathogen DNA on disposable screen-printed carbon electrodes. This 60 min assay relied on the rapid isothermal amplification of target pathogen DNA sequences by recombinase polymerase amplification (RPA) followed by gold nanoparticle-based electrochemical assessment with differential pulse voltammetry (DPV)...
January 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28093096/structural-biology-of-supramolecular-assemblies-by-magic-angle-spinning-nmr-spectroscopy
#7
Caitlin M Quinn, Tatyana Polenova
In recent years, exciting developments in instrument technology and experimental methodology have advanced the field of magic-angle spinning (MAS) nuclear magnetic resonance (NMR) to new heights. Contemporary MAS NMR yields atomic-level insights into structure and dynamics of an astounding range of biological systems, many of which cannot be studied by other methods. With the advent of fast MAS, proton detection, and novel pulse sequences, large supramolecular assemblies, such as cytoskeletal proteins and intact viruses, are now accessible for detailed analysis...
January 2017: Quarterly Reviews of Biophysics
https://www.readbyqxmd.com/read/28092475/temperature-development-on-the-external-root-surface-during-laser-assisted-endodontic-treatment-applying-a-microchopped-mode-of-a-980%C3%A2-nm-diode-laser
#8
Franziska Beer, Eleftherios Terry R Farmakis, Josip Kopic, Christoph Kurzmann, Andreas Moritz
OBJECTIVE: The aim of this article was to investigate the temperature increase of the external root surface during laser-assisted endodontic treatment using a diode laser (980 nm) in a microchopped mode. METHODS: Ten freshly extracted, human maxillary incisors with mature apices were collected, prepared to size F4 at working length (ProTaper; Dentsply Maillefer, Ballaigues, Switzerland), mounted to a holder, and irradiated (using spiral movements in coronal direction) with a diode laser (GENTLEray 980 Classic Plus; KaVo, Biberach, Germany) with a 200 μm fiber in four different treatment groups: Group 1 (control group) was irradiated in six cycles of 5-sec irradiation/20-sec pause with 2...
January 12, 2017: Photomedicine and Laser Surgery
https://www.readbyqxmd.com/read/28090713/nucleotide-independent-copper-ii-based-distance-measurements-in-dna-by-pulsed-esr-spectroscopy
#9
Matthew J Lawless, Jessica L Sarver, Sunil Saxena
A site-specific Cu(2+) binding motif within a DNA duplex for distance measurements by ESR spectroscopy is reported. This motif utilizes a commercially available 2,2'-dipicolylamine (DPA) phosphormadite easily incorporated into any DNA oligonucleotide during initial DNA synthesis. The method only requires the simple post-synthetic addition of Cu(2+) without the need for further chemical modification. Notably, the label is positioned within the DNA duplex, as opposed to outside the helical perimeter, for an accurate measurement of duplex distance...
January 16, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28090666/quantitative-ultrashort-echo-time-imaging-for-assessment-of-massive-iron-overload-at-1-5-and-3-tesla
#10
Axel J Krafft, Ralf B Loeffler, Ruitian Song, Aaryani Tipirneni-Sajja, M Beth McCarville, Matthew D Robson, Jane S Hankins, Claudia M Hillenbrand
PURPOSE: Hepatic iron content (HIC) quantification via transverse relaxation rate (R2*)-MRI using multi-gradient echo (mGRE) imaging is compromised toward high HIC or at higher fields due to the rapid signal decay. Our study aims at presenting an optimized 2D ultrashort echo time (UTE) sequence for R2* quantification to overcome these limitations. METHODS: Two-dimensional UTE imaging was realized via half-pulse excitation and radial center-out sampling. The sequence includes chemically selective saturation pulses to reduce streaking artifacts from subcutaneous fat, and spatial saturation (sSAT) bands to suppress out-of-slice signals...
January 16, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28090656/real-time-monitoring-of-tissue-displacement-and-temperature-changes-during-mr-guided-high-intensity-focused-ultrasound
#11
Pierre Bour, Fabrice Marquet, Valéry Ozenne, Solenn Toupin, Erik Dumont, Jean-François Aubry, Matthieu Lepetit-Coiffe, Bruno Quesson
PURPOSE: The therapy endpoint most commonly used in MR-guided high intensity focused ultrasound is the thermal dose. Although namely correlated with nonviable tissue, it does not account for changes in mechanical properties of tissue during ablation. This study presents a new acquisition sequence for multislice, subsecond and simultaneous imaging of tissue temperature and displacement during ablation. METHODS: A single-shot echo planar imaging sequence was implemented using a pair of motion-encoding gradients, with alternated polarities...
January 16, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28090655/30-second-bound-and-pore-water-concentration-mapping-of-cortical-bone-using-2d-ute-with-optimized-half-pulses
#12
Mary Kate Manhard, Kevin D Harkins, Daniel F Gochberg, Jeffry S Nyman, Mark D Does
PURPOSE: MRI of cortical bone has the potential to offer new information about fracture risk. Current methods are typically performed with 3D acquisitions, which suffer from long scan times and are generally limited to extremities. This work proposes using 2D UTE with half pulses for quantitatively mapping bound and pore water in cortical bone. METHODS: Half-pulse 2D UTE methods were implemented on a 3T Philips Achieva scanner using an optimized slice-select gradient waveform, with preparation pulses to selectively image bound or pore water...
January 16, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28090447/quantitative-sodium-magnetic-resonance-imaging-of-cartilage-muscle-and-tendon
#13
REVIEW
Neal K Bangerter, Grayson J Tarbox, Meredith D Taylor, Joshua D Kaggie
Sodium magnetic resonance imaging (MRI), or imaging of the 23Na nucleus, has been under exploration for several decades, and holds promise for potentially revealing additional biochemical information about the health of tissues that cannot currently be obtained from conventional hydrogen (or proton) MRI. This additional information could serve as an important complement to conventional MRI for many applications. However, despite these exciting possibilities, sodium MRI is not yet used routinely in clinical practice, and will likely remain strictly in the domain of exploratory research for the coming decade...
December 2016: Quantitative Imaging in Medicine and Surgery
https://www.readbyqxmd.com/read/28079703/metal-artifact-reduction-magnetic-resonance-imaging-around-arthroplasty-implants-the-negative-effect-of-long-echo-trains-on-the-implant-related-artifact
#14
Neil M Kumar, Cesar de Cesar Netto, Lew C Schon, Jan Fritz
OBJECTIVES: Long echo train length (ETL) is an often recommended but unproven technique to decrease metal artifacts on magnetic resonance imaging (MRI) scans. Therefore, we quantitatively and qualitatively assessed the effects of ETL on metal artifact on MRI scans using a cobalt-chromium-containing arthroplasty implant system. MATERIALS AND METHODS: Using a total ankle arthroplasty system implanted into a human cadaver ankle and a clinical 1.5 T MRI system, turbo spin echo (TSE) pulse sequences were acquired with ETL ranging from 3 to 23 and receiver bandwidth (BW) from 100 to 750 Hz/pixel, whereas effective echo time and spatial resolution were controlled...
January 9, 2017: Investigative Radiology
https://www.readbyqxmd.com/read/28077267/rapid-whole-brain-myelin-water-content-mapping-without-an-external-water-standard-at-1-5t
#15
Thanh D Nguyen, Pascal Spincemaille, Susan A Gauthier, Yi Wang
The objective of this study is to develop rapid whole brain mapping of myelin water content (MWC) at 1.5T. The Fast Acquisition with Spiral Trajectory and T2prep (FAST-T2) pulse sequence originally developed for myelin water fraction (MWF) mapping was modified to obtain fast mapping of T1 and receiver coil sensitivity needed for MWC computation. The accuracy of the proposed T1 mapping was evaluated by comparing with the standard IR-FSE method. Numerical simulations were performed to assess the accuracy and reliability of the proposed MWC mapping...
January 7, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28076722/is-there-long-term-signal-intensity-increase-in-the-central-nervous-system-on-t1-weighted-images-after-mr-imaging-with-the-hepatospecific-contrast-agent-gadoxetic-acid-a-cross-sectional-study-in-91-patients
#16
Johannes Kahn, Helena Posch, Ingo G Steffen, Dominik Geisel, Christian Bauknecht, Thomas Liebig, Timm Denecke
Purpose To evaluate whether there is T1-weighted signal intensity (SI) increase in the dentate nucleus (DN) and globus pallidus (GP) in relation to the middle cerebellar peduncle (MCP), pons, and thalamus after repeated administration of the liver-specific contrast agent gadoxetic acid. Materials and Methods This was an institutional review board-approved, prospectively conducted (written informed consent acquired), cross-sectional study performed in a consecutively selected patient group (n = 91; patients received one to 37 doses of gadoxetic acid) and a control group (n = 52; subjects had never received injections of gadolinium-based contrast agent) examined with a standard T1-weighted two-dimensional spin-echo pulse sequence of the brain at 1...
January 11, 2017: Radiology
https://www.readbyqxmd.com/read/28075235/staphylococcus-pseudintermedius-human-infection-cases-in-spain-dog-to-human-transmission
#17
Carmen Lozano, Antonio Rezusta, Isabel Ferrer, Vanesa Pérez-Laguna, Myriam Zarazaga, Laura Ruiz-Ripa, María José Revillo, Carmen Torres
Staphylococcus pseudintermedius is an opportunistic pathogen that has been identified as infectious agent or colonizer mainly in dogs. S. pseudintermedius has been also detected in humans and more specifically in people in contact with dogs. In this study, the possible S. pseudintermedius pet-to-human transmission was analyzed in four clinical human cases. Two patients were dog owners and S. pseudintermedius was also detected as colonizer in these healthy animals. S. pseudintermedius isolates from patients and dogs of the same household showed identical pulsed-field gel electrophoresis patterns, sequence types (STs), and antimicrobial resistance phenotypes and genotypes, and were methicillin susceptible...
January 11, 2017: Vector Borne and Zoonotic Diseases
https://www.readbyqxmd.com/read/28074528/respiratory-motion-prediction-and-prospective-correction-for-free-breathing-arterial-spin-labeled-perfusion-mri-of-the-kidneys
#18
Hao Song, Dan Ruan, Wenyang Liu, V Andrew Stenger, Rolf Pohmann, Maria A Fernandez Seara, Tejas Nair, Sungkyu Jung, Jingqin Luo, Yuichi Motai, Jingfei Ma, John D Hazle, H Michael Gach
PURPOSE: Respiratory motion prediction using an artificial neural network (ANN) was integrated with pseudocontinuous arterial spin labeling (pCASL) MRI to allow free-breathing perfusion measurements in the kidney. In this study, we evaluated the performance of the ANN to accurately predict the location of the kidneys during image acquisition. METHODS: A pencil-beam navigator was integrated with a pCASL sequence to measure lung/diaphragm motion during ANN training and the pCASL transit delay...
January 11, 2017: Medical Physics
https://www.readbyqxmd.com/read/28074126/the-emergence-of-carbapenem-resistant-klebsiella-pneumoniae-in-malaysia-correlation-between-microbiological-trends-with-host-characteristics-and-clinical-factors
#19
Ye-Mun Low, Polly Soo-Xi Yap, Kartini Abdul Jabar, Sasheela Ponnampalavanar, Rina Karunakaran, Rukumani Velayuthan, Chun-Wie Chong, Sazaly Abu Bakar, Mohd Yasim Md Yusof, Cindy Shuan-Ju Teh
BACKGROUND: Carbapenem resistant Enterobacteriaceae is a growing concern worldwide including Malaysia. The emergence of this pathogen is worrying because carbapenem is one of the 'last-line' antibiotics. The main objective of this study was to determine the prevalence of genetic mechanisms and clinical risk factors of carbapenem resistant Klebsiella pneumoniae (K. pneumoniae) in Malaysia. METHODS: In this study, seventeen carbapenem resistant K. pneumoniae strains isolated from a tertiary teaching hospital in 2013 were studied...
2017: Antimicrobial Resistance and Infection Control
https://www.readbyqxmd.com/read/28068519/qualification-of-hsqc-methods-for-quantitative-composition-of-heparin-and-low-molecular-weight-heparins
#20
Lucio Mauri, Giovanni Boccardi, Giangiacomo Torri, Michael Karfunkle, Eleonora Macchi, Laura Muzi, David Keire, Marco Guerrini
An NMR HSQC method has recently been proposed for the quantitative determination of the mono- and disaccharide subunits of heparin and low molecular weight heparins (LMWH). The focus of the current study was the validation of this procedure to make the 2D-NMR method suitable for pharmaceutical quality control applications. Pre-validation work investigated the effects of several experimental parameters to assess robustness and to optimize critical factors. Important experimental parameters were pulse sequence selection, equilibration interval between pulse trains and temperature...
December 26, 2016: Journal of Pharmaceutical and Biomedical Analysis
keyword
keyword
63292
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"