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P927Electrophysiological features in children with premature ventricular contractions. Europace 2020. [DOI: 10.1093/europace/euaa162.334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Background
Premature ventricular contractions (PVCs) is the one of the most frequent arrhythmias in children. There is no clear understanding regarding the causes of PVCs in children without structural heart diseases. There is also little information about the state of the conduction system (CS) of the heart in children with PVCs. Purpose:The aims of the study were to estimate the electrophysiological properties of the sinus node (SN) and atrioventricular node (AVN) in children with PVCs, and to evaluate the effect of atropine test on the frequency and nature of the PVCs. Methods: 167 children(54(32,3%) girls and 113(67,7%) boys with PVCs without structural heart disease were examined. Mean age at the time of the first examination was 14,5 ± 5,3years (6-18 years). Examination included: ECG, 24-hour Holter monitor (HM), echocardiogram, treadmill test, transesophageal pacing study (TEPS), atropine test.Results:The duration of the PVCs was 3,3 ± 1,5years (6-14 years). The burden of the PVCs was 7-29% according to HM data. 5(3%) children had syncope. Frequent PVCs were recorded in 43(25,7%) patients, single PVC in 59 (35,3%), and the rest of children did not have PVCs during TEPS. SN recovery time (SNRT) was 1118,1 ± 292,4ms (541-2300ms) which exceeded the age-dependent limit in 23(13,7%) children. Corrected SNRT was 350,1 ± 171,1ms (41-1317ms), which exceeded the age-dependent limit in 15(8,9%) children. Max.rate of 1:1 conduction through AVN was 166,7 ± 39,1 imp/min (90-220 imp/min); in 16(9,6%) children it was less than 120 imp/min, while 8 (4,8%) children had enhanced AV nodal conduction (more than 200imp/min). The effective refractory period (ERP) of AVN was 325,1 ± 91,7ms (190-650ms), exceeding the age norm in 18(10,7%) children. 16(9,6%) children had a discontinuous AV nodal conduction. The frequency of stimulation which suppressed PVCs was 100-160imp/min. Atropine test was performed in 100(59,9%) children (0,1% sol. Atropini sulfatis 0,02 mg/kg IV). After administration of atropine the increase in heart rate constituted 7-131%, with an average of 57%. The SNRT was 665,5 ± 154,4 ms (406-1512ms), maximal rate of 1:1 conduction through AVN was 213,2 ± 31,9 imp/min (150-270 imp/min). Among patients who initially had PVCs during TEPS, after atropine test PVCs disappeared in 61(59,8%) children, in 16(15,7%) children there was a significant decrease, and 4(3,9%) patients had an increase in the number of PVCs and episodes of stable ventricular bigeminy, and in 1(0.9%) child there were short runs of ventricular tachycardia (up to 8 QRS complexes).Conclusions: In children with PVCs normal electrophysiological parameters of cardiac CS were noted in most cases. In 35% of children there was a hypervagotonic influence on SN or AVN, and in 75,5% cases there was a disappearance or decrease in PVCs after atropine test. This suggests that the preferential nature of PVCs in children without structural heart diseases is autonomic system dependent
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Abstract
The superconducting synchrotron Nuclotron [1] is the one of the main parts of the NICA/MPD project [2] in the Laboratory of High Energy Physics of JINR in Dubna. During the work on updating the Nuclotron control and monitoring systems the new injection beam profiles measurement system was developed, produced and successfully put into operation. The development process and operation results are described.
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Near-Edge Soft X-ray Absorption Mass Spectrometry of Protonated Melittin. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2018; 29:2138-2151. [PMID: 30047073 DOI: 10.1007/s13361-018-2035-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Revised: 07/10/2018] [Accepted: 07/10/2018] [Indexed: 06/08/2023]
Abstract
We have investigated the photoionization and photofragmentation yields of gas-phase multiply protonated melittin cations for photon energies at the K-shell absorption edges of carbon, nitrogen, and oxygen. Two similar experimental approaches were employed. In both experiments, mass selected [melittin+qH]q+ (q=2-4) ions were accumulated in radiofrequency ion traps. The trap content was exposed to intense beams of monochromatic soft X-ray photons from synchrotron beamlines and photoproducts were analyzed by means of time-of-flight mass spectrometry. Mass spectra were recorded for fixed photon energies, and partial ion yield spectra were recorded as a function of photon energy. The combination of mass spectrometry and soft X-ray spectroscopy allows for a direct correlation of protein electronic structure with various photoionization channels. Non-dissociative single and double ionization are used as a reference. The contribution of both channels to various backbone scission channels is quantified and related to activation energies and protonation sites. Soft X-ray absorption mass spectrometry combines fast energy deposition with single and double ionization and could complement established activation techniques. Graphical Abstract ᅟ.
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Soft X-ray Spectroscopy as a Probe for Gas-Phase Protein Structure: Electron Impact Ionization from Within. Chemistry 2018; 24:7631-7636. [PMID: 29637635 PMCID: PMC6001477 DOI: 10.1002/chem.201801440] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Revised: 04/03/2018] [Indexed: 11/10/2022]
Abstract
Preservation of protein conformation upon transfer into the gas phase is key for structure determination of free single molecules, for example using X-ray free-electron lasers. In the gas phase, the helicity of melittin decreases strongly as the protein's protonation state increases. We demonstrate the sensitivity of soft X-ray spectroscopy to the gas-phase structure of melittin cations ([melittin+qH]q+ , q=2-4) in a cryogenic linear radiofrequency ion trap. With increasing helicity, we observe a decrease of the dominating carbon 1 s-π* transition in the amide C=O bonds for non-dissociative single ionization and an increase for non-dissociative double ionization. As the underlying mechanism we identify inelastic electron scattering. Using an independent atom model, we show that the more compact nature of the helical protein conformation substantially increases the probability for off-site intramolecular ionization by inelastic Auger electron scattering.
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P768Latent type of Wolff-Parkinson-White syndrome in children. Europace 2018. [DOI: 10.1093/europace/euy015.372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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P1795Presyncope and syncope events in pediatric patients with paroxysmal supraventricular tachycardia. Europace 2017. [DOI: 10.1093/ehjci/eux161.104] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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P1797Characteristics and clinical significance of bradycardia in children. Europace 2017. [DOI: 10.1093/ehjci/eux161.106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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P1041The results of the pharmacological treatment in children with chronic sinus tachycardia and focal atrial tachycardia. Europace 2017. [DOI: 10.1093/ehjci/eux151.221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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P1796Classification and diagnostic features of supraventricular tachycardia in children. Europace 2017. [DOI: 10.1093/ehjci/eux161.105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Single-photon absorption of isolated collagen mimetic peptides and triple-helix models in the VUV-X energy range. Phys Chem Chem Phys 2017; 19:18321-18329. [DOI: 10.1039/c7cp02527k] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
By monitoring ionization and fragmentation after single-photon absorption, we show that an isolated collagen triple helix model is stabilized by proline hydroxylation.
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Radical-driven processes within a peptidic sequence of type I collagen upon single-photon ionisation in the gas phase. Phys Chem Chem Phys 2017; 19:22895-22904. [DOI: 10.1039/c7cp03376a] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Radical creation after single-photon ionisation of collagen peptides induces the loss of molecules from amino-acid residue side-chains.
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A comparative VUV absorption mass-spectroscopy study on protonated peptides of different size. Phys Chem Chem Phys 2017; 19:20608-20618. [DOI: 10.1039/c7cp03203j] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The response of gas-phase peptides upon vacuum ultraviolet absorption depends strongly on the peptide size.
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Multiple Ionization of Free Ubiquitin Molecular Ions in Extreme Ultraviolet Free-Electron Laser Pulses. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201605335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Multiple Ionization of Free Ubiquitin Molecular Ions in Extreme Ultraviolet Free-Electron Laser Pulses. Angew Chem Int Ed Engl 2016; 55:10741-5. [DOI: 10.1002/anie.201605335] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Indexed: 11/09/2022]
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Near edge X-ray absorption mass spectrometry of gas phase proteins: the influence of protein size. Phys Chem Chem Phys 2016; 18:26213-26223. [DOI: 10.1039/c6cp05254a] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The response of gas-phase proteins upon soft X-ray absorption depends strongly on the proteins size.
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Abstract
The Zeeman effect in the excited A 2Pi(3/2) state of CaF is measured and analyzed over a wide range of magnetic fields. It is found that the splitting of the Zeeman levels is largely determined by the coupling between different rotational states and there are no low-field seeking states in the J=3/2 manifold of Zeeman levels at high magnetic fields. A model of the Zeeman spectrum based on the ligand-field theory of CaF is shown to be accurate in the interval of magnetic fields 0-5 Tesla. This demonstrates that the magnetic moment of the CaF(A 2Pi(3/2)) molecule is effectively determined by the spin angular momentum of a single electron and the orbital motion of the valence electron around the Ca2+ core. An analysis of the Zeeman spectrum as a function of the molecular rotational constant indicates that 2Pi(3/2) molecules should have significant rotational constants (at least as large as twice the rotational constant of CaF) to be amenable to magnetic trapping in high fields.
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Normal electrophysiological parameters of slaus node function at children depending on age. Europace 2001. [DOI: 10.1016/eupace/2.supplement_1.a22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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