Read by QxMD icon Read

Freeze on gate

Narges Salehi, Arman Rahmim, Emad Fatemizadeh, Afshin Akbarzadeh, Mohammad Hossein Farahani, Saeed Farzanefar, Mohammad Reza Ay
INTRODUCTION: Cardiac contraction significantly degrades quality and quantitative accuracy of gated myocardial perfusion SPECT (MPS) images. In this study, we aimed to explore different techniques in motion-compensated temporal processing of MPS images and their impact on image quality and quantitative accuracy. MATERIAL AND METHOD: 50 patients without known heart condition underwent gated MPS. 3D motion compensation methods using Motion Freezing by Cedars Sinai (MF), Log-domain Diffeomorphic Demons (LDD) and Free-Form Deformation (FFD) were applied to warp all image phases to fit the end-diastolic (ED) phase...
May 2018: Physica Medica: PM
M Gregor Madej, Christine M Ziegler
Cryo-electron microscopy (cryo-EM) permits the determination of atomic protein structures by averaging large numbers of individual projection images recorded at cryogenic temperatures-a method termed single-particle analysis. The cryo-preservation traps proteins within a thin glass-like ice layer, making literally a freeze image of proteins in solution. Projections of randomly adopted orientations are merged to reconstruct a 3D density map. While atomic resolution for highly symmetric viruses was achieved already in 2009, the development of new sensitive and fast electron detectors has enabled cryo-EM for smaller and asymmetrical proteins including fragile membrane proteins...
January 17, 2018: Pflügers Archiv: European Journal of Physiology
Rafael Luján, Carolina Aguado, Francisco Ciruela, Javier Cózar, David Kleindienst, Luis de la Ossa, Bernhard Bettler, Kevin Wickman, Masahiko Watanabe, Ryuichi Shigemoto, Yugo Fukazawa
Metabotropic GABAB receptors mediate slow inhibitory effects presynaptically and postsynaptically through the modulation of different effector signalling pathways. Here, we analysed the distribution of GABAB receptors using highly sensitive SDS-digested freeze-fracture replica labelling in mouse cerebellar Purkinje cells. Immunoreactivity for GABAB1 was observed on presynaptic and, more abundantly, on postsynaptic compartments, showing both scattered and clustered distribution patterns. Quantitative analysis of immunoparticles revealed a somato-dendritic gradient, with the density of immunoparticles increasing 26-fold from somata to dendritic spines...
April 2018: Brain Structure & Function
Alexis Matwyschuk
Having laid down previously the foundations of the multiple-wavelength range-gated active imaging (WRAI) principle in flash mode and accumulation mode, its use in superimposed style for the direct tracking of moving objects was studied. The movement is supposed to be in a transverse plane of the scene. Each emitted laser pulse with a different wavelength visualizes the object at a specific time. Therefore, the wavelength set allows us to freeze the different positions of the object in the recorded image according to the laser emission period...
September 20, 2017: Applied Optics
Aslı Filiz, Nermin Tepe, Sajedeh Eftekhari, H Evren Boran, Ergin Dilekoz, Lars Edvinsson, Hayrunnisa Bolay
Background and objective The present study aimed to investigate the effects of selective calcitonin gene related peptide (CGRP) receptor antagonist (MK-8825) on cortical spreading depression (CSD) induced pain behavior and anxiety in freely-moving rats, and neuronal activation in the correlated anatomical regions. Methods CSD was induced while keeping all meningeal layers and BBB intact and MK-8825 was administered in two different doses. Regional cerebral blood flow (rCBF), arterial pressure and DC shift were recorded...
January 1, 2017: Cephalalgia: An International Journal of Headache
J-Y Puigbò, G Maffei, I Herreros, M Ceresa, M A González Ballester, P F M J Verschure
The embodied mammalian brain evolved to adapt to an only partially known and knowable world. The adaptive labeling of the world is critically dependent on the neocortex which in turn is modulated by a range of subcortical systems such as the thalamus, ventral striatum, and the amygdala. A particular case in point is the learning paradigm of classical conditioning where acquired representations of states of the world such as sounds and visual features are associated with predefined discrete behavioral responses such as eye blinks and freezing...
January 2018: Molecular Neurobiology
Noel M Gately, James E Kennedy
Hot melt extrusion (HME) is considered an efficient technique in developing solid molecular dispersions, and has been demonstrated to provide sustained, modified and targeted drug delivery resulting in improved bioavailability. However, most commercial enteric or pH-responsive polymers are relatively difficult to process or have high Glass Transition Temperature (Tg) values, making their use with temperature-sensitive drugs, probiotics or biologics not viable. Shellac is a natural thermoplastic, and after a review of current literature on the pharmaceutical HME process, a possible gap in the knowledge of the use of shellac to produce dosage forms by means of HME was identified...
September 22, 2017: Pharmaceutics
Yvette Véronique Ntsogo Enguéné, Gilles Phan, Cyril Garnier, Arnaud Ducruix, Thierry Prangé, Isabelle Broutin
Tripartite efflux pumps are among the main actors responsible for antibiotics resistance in Gram-negative bacteria. In the last two decades, structural studies gave crucial information about the assembly interfaces and the mechanistic motions. Thus rigidifying the assembly seems to be an interesting way to hamper the drug efflux. In this context, xenon is a suitable probe for checking whether small ligands could act as conformational lockers by targeting hydrophobic cavities. Here we focus on OprN, the outer membrane channel of the MexEF efflux pump from Pseudomonas aeruginosa...
2017: PloS One
Xinhui Wang, Arman Rahmim, Jing Tang
PURPOSE: Myocardial perfusion (MP) PET imaging is a powerful tool in risk assessment and stratification of patients with coronary artery disease. Involuntary organ motion degrades cardiac PET image resolution, while respiratory and/or cardiac gating to freeze the motion leads to noisier reconstructed images due to reduced counts in the gated frames. In this work, we propose an MRI-assisted dual motion correction method to compensate for respiratory and cardiac motion in MP PET data and study the impact of dual motion correction on MP defect detection using systematically designed experiments...
June 24, 2017: Medical Physics
Camilo Aponte-Santamaría, Gerhard Fischer, Petra Båth, Richard Neutze, Bert L de Groot
Regulation of aquaporins is a key process of living organisms to counteract sudden osmotic changes. Aqy1, which is a water transporting aquaporin of the yeast Pichia pastoris, is suggested to be gated by chemo-mechanical stimuli as a protective regulatory-response against rapid freezing. Here, we tested the influence of temperature by determining the X-ray structure of Aqy1 at room temperature (RT) at 1.3 Å resolution, and by exploring the structural dynamics of Aqy1 during freezing through molecular dynamics simulations...
June 21, 2017: Scientific Reports
Asher J Albertson, Andrew S Bohannon, John J Hablitz
Cortical malformations are often associated with pharmaco-resistant epilepsy. Alterations in hyperpolarization-activated, cyclic nucleotide-gated, non-specific cation (HCN) channels have been shown to contribute to malformation associated hyperexcitability. We have recently demonstrated that expression of HCN channels and I h current amplitudes are reduced in layer (L) 5 pyramidal neurons of rats with freeze lesion induced malformations. These changes were associated with an increased EPSP temporal summation...
2017: Frontiers in Cellular Neuroscience
A R Ullah, J G Gluschke, P Krogstrup, C B Sørensen, J Nygård, A P Micolich
GaAs was central to the development of quantum devices but is rarely used for nanowire-based quantum devices with InAs, InSb and SiGe instead taking the leading role. p-type GaAs nanowires offer a path to studying strongly confined 0D and 1D hole systems with strong spin-orbit effects, motivating our development of nanowire transistors featuring Be-doped p-type GaAs nanowires, AuBe alloy contacts and patterned local gate electrodes towards making nanowire-based quantum hole devices. We report on nanowire transistors with traditional substrate back-gates and EBL-defined metal/oxide top-gates produced using GaAs nanowires with three different Be-doping densities and various AuBe contact processing recipes...
March 3, 2017: Nanotechnology
Kilian Bärwinkel, Markus M Herling, Martin Rieß, Hiroshi Sato, Liangchun Li, Yamini S Avadhut, Tobias W Kemnitzer, Hussein Kalo, Jürgen Senker, Ryotaro Matsuda, Susumu Kitagawa, Josef Breu
Microporous organically pillared layered silicates (MOPS) are a class of microporous hybrid materials that, by varying pillar density, allows for optimization of guest recognition without the need to explore different framework topologies. MOPS are found to be capable of discriminating two very similar gases, carbon dioxide and acetylene, by selective gate-opening solely through quenching pillar dynamics. Contrary to conventional gate-opening in metal organic frameworks, the additional adsorption capacity is realized without macroscopic volume changes, thus avoiding mechanical stress on the framework...
January 18, 2017: Journal of the American Chemical Society
Kei Wagatsuma, Tatsufumi Osawa, Naoki Yokokawa, Kenta Miwa, Keiichi Oda, Yoshiro Kudo, Yasushi Unno, Kimiteru Ito, Kenji Ishii
OBJECTIVE: The present study aimed to determine the qualitative and quantitative accuracy of the Q.Freeze algorithm in PET/CT images of liver tumors. METHODS: A body phantom and hot spheres representing liver tumors contained 5.3 and 21.2 kBq/mL of a solution containing (18)F radioactivity, respectively. The phantoms were moved in the superior-inferior direction at a motion displacement of 20 mm. Conventional respiratory-gated (RG) and Q.Freeze images were sorted into 6, 10, and 13 phase-groups...
2016: Nihon Hoshasen Gijutsu Gakkai Zasshi
C E Koch, M S Bartlang, J T Kiehn, L Lucke, N Naujokat, C Helfrich-Förster, S O Reber, H Oster
In modern societies, the risk of developing a whole array of affective and somatic disorders is associated with the prevalence of frequent psychosocial stress. Therefore, a better understanding of adaptive stress responses and their underlying molecular mechanisms is of high clinical interest. In response to an acute stressor, each organism can either show passive freezing or active fight-or-flight behaviour, with activation of sympathetic nervous system and the hypothalamus-pituitary-adrenal (HPA) axis providing the necessary energy for the latter by releasing catecholamines and glucocorticoids (GC)...
December 2016: Journal of Endocrinology
Jennifer Lemieux, Christine Jobin, Carl Simard, Sonia Néron
The cryopreservation of human lymphocytes is an essential step for the achievement of several cellular therapies. Besides, T cells are considered as promising actors in cancer therapy for their cytotoxic and regulatory properties. Consequently, the development of tools to monitor the impact of freezing and thawing processes on their fine distribution may be an asset to achieve quality control in cellular therapy. In this study, the phenotypes of freshly isolated human mononuclear cells were compared to those observed following one cycle of cryopreservation and rest periods 0h, 1h and 24h after thawing but before staining...
July 2016: Journal of Immunological Methods
Kexiong Zhang, Masatomo Sumiya, Meiyong Liao, Yasuo Koide, Liwen Sang
The concept of p-channel InGaN/GaN heterostructure field effect transistor (FET) using a two-dimensional hole gas (2DHG) induced by polarization effect is demonstrated. The existence of 2DHG near the lower interface of InGaN/GaN heterostructure is verified by theoretical simulation and capacitance-voltage profiling. The metal-oxide-semiconductor FET (MOSFET) with Al2O3 gate dielectric shows a drain-source current density of 0.51 mA/mm at the gate voltage of -2 V and drain bias of -15 V, an ON/OFF ratio of two orders of magnitude and effective hole mobility of 10 cm(2)/Vs at room temperature...
March 29, 2016: Scientific Reports
Georg Griesinger, Pierre J M Verweij, Davis Gates, Paul Devroey, Keith Gordon, Barbara J Stegmann, Basil C Tarlatzis
STUDY QUESTION: What is the threshold for the prediction of moderate to severe or severe ovarian hyperstimulation syndrome (OHSS) based on the number of growing follicles ≥ 11 mm and/or estradiol (E2) levels? SUMMARY ANSWER: The optimal threshold of follicles ≥11 mm on the day of hCG to identify those at risk was 19 for both moderate to severe OHSS and for severe OHSS. Estradiol (E2) levels were less prognostic of OHSS than the number of follicles ≥ 11 mm...
2016: PloS One
Marcus Lira Brandão, Amanda Ribeiro de Oliveira, Sangu Muthuraju, Ana Caroline Colombo, Viviane Mitsuko Saito, Teddy Talbot
A reduction of dopamine release or D2 receptor blockade in the terminal fields of the mesolimbic system, particularly the amygdala, clearly reduces conditioned fear. Similar D2 receptor antagonism in the neural substrates of fear in the midbrain tectum attenuates the processing of unconditioned aversive information. However, the implications of the interplay between opposing actions of dopamine in the rostral and caudal segments of the dopaminergic system are still unclear. Previous studies from this laboratory have reported the effects of dopaminergic drugs on behavior in rats in the elevated plus maze, auditory-evoked potentials (AEPs) recorded from the midbrain tectum, fear-potentiated startle, and conditioned freezing...
November 14, 2015: FEBS Letters
Lijuan Fan, Jiwang Zhang, Dongsheng Xu, Zhi Dong, Xu Li, Liren Zhang
BACKGROUND: Although coronary computed tomography angiography (CCTA) can detect coronary artery disease, limited temporal resolution of computed tomographic scanners may allow for motion artifacts, which may result in nonevaluable coronary segments. OBJECTIVE: This study aimed to assess Snapshot Freeze (SSF) Motion Correction algorithm for its effect on image quality of CCTA. METHODS AND RESULTS: Thirty patients underwent prospective electrocardiographic (ECG)-gating CCTA and 30 patients underwent retrospective ECG gating...
March 2015: Journal of Computer Assisted Tomography
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"