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https://www.readbyqxmd.com/read/29471275/frequency-agile-gyrotron-for-electron-decoupling-and-pulsed-dynamic-nuclear-polarization
#1
Faith J Scott, Edward P Saliba, Brice J Albert, Nicholas Alaniva, Erika L Sesti, Chukun Gao, Natalie C Golota, Eric J Choi, Anil P Jagtap, Johannes J Wittmann, Michael Eckardt, Wolfgang Harneit, Björn Corzilius, Snorri Th Sigurdsson, Alexander B Barnes
We describe a frequency-agile gyrotron which can generate frequency-chirped microwave pulses. An arbitrary waveform generator (AWG) within the NMR spectrometer controls the microwave frequency, enabling synchronized pulsed control of both electron and nuclear spins. We demonstrate that the acceleration of emitted electrons, and thus the microwave frequency, can be quickly changed by varying the anode voltage. This strategy results in much faster frequency response than can be achieved by changing the potential of the electron emitter, and does not require a custom triode electron gun...
February 12, 2018: Journal of Magnetic Resonance
https://www.readbyqxmd.com/read/29470259/pure-tone-audiometry-with-forward-pressure-level-calibration-leads-to-clinically-relevant-improvements-in-test-retest-reliability
#2
Judi A Lapsley Miller, Charlotte M Reed, Sarah R Robinson, Zachary D Perez
OBJECTIVES: Clinical pure-tone audiometry is conducted using stimuli delivered through supra-aural headphones or insert earphones. The stimuli are calibrated in an acoustic (average ear) coupler. Deviations in individual-ear acoustics from the coupler acoustics affect test validity, and variations in probe insertion and headphone placement affect both test validity and test-retest reliability. Using an insert earphone designed for otoacoustic emission testing, which contains a microphone and loudspeaker, an individualized in-the-ear calibration can be calculated from the ear-canal sound pressure measured at the microphone...
February 21, 2018: Ear and Hearing
https://www.readbyqxmd.com/read/29469869/nondestructive-evaluation-of-demineralized-enamel-in-a-human-incisor-and-molar-using-laser-ultrasonics
#3
Kaihua Sun, Ling Yuan, Zhonghua Shen, Qingping Zhu
This study aims to evaluate early caries in human teeth with different geometry structures by using the dispersion curves of a surface acoustic wave (SAW) generated by a pulsed laser. Through the finite element method, SAWs propagating on teeth models with different enamel thickness and curvature radius were simulated, and the influence of the geometry difference on the dispersion curves of SAWs was discussed. Laser ultrasonic experiments were performed on an extracted human incisor and molar with different demineralization conditions...
February 10, 2018: Applied Optics
https://www.readbyqxmd.com/read/29469164/heart-rate-variability-affected-by-radiofrequency-electromagnetic-field-in-adolescent-students
#4
Jakub Misek, Igor Belyaev, Viera Jakusova, Ingrid Tonhajzerova, Jan Barabas, Jan Jakus
This study examines the possible effect of radiofrequency (RF) electromagnetic fields (EMF) on the autonomic nervous system (ANS). The effect of RF EMF on ANS activity was studied by measuring heart rate variability (HRV) during ortho-clinostatic test (i.e., transition from lying to standing and back) in 46 healthy grammar school students. A 1788 MHz pulsed wave with intensity of 54 ± 1.6 V/m was applied intermittently for 18 min in each trial. Maximum specific absorption rate (SAR10 ) value was determined to 0...
February 22, 2018: Bioelectromagnetics
https://www.readbyqxmd.com/read/29466197/-assessment-of-vascular-stiffness-in-normotensive-patients-with-familial-hypercholesterolemia
#5
V A Korneva, T Y Kuznetsova, G P Tikhova
AIM: to analyze parameters of vascular stiffness and augmentation index in patients with familial hypercholesterolemia (FH). MATERIALS AND METHODS: We compared parameters of vascular stiffness of 88 normotensive FH patients (mean age 41.95±1.43 years, 43 men [48.9 %]) and 68 subjects with normal blood lipid spectrum (mean age 37.58±1.02 years, 21 men [30.9 %]). FH was diagnosed according to the criteria of the Dutch Lipid Clinic Network. Examination included lipid profile, 24‑hour blood pressure (BP) monitoring with assessment of arterial stiffness...
February 2018: Kardiologiia
https://www.readbyqxmd.com/read/29465201/-pulse-wave-transit-time-one-more-attempt-of-non-invasive-cardiac-output-measurement
#6
B A Akselrod, L A Tolstova, T A Pshenichniy, S V Fedulova
BACKGROUND: Estimated continuous cardiac output (esCCOTM) based on pulse wave transit time is one of alternative non-invasive CO measurement techniques. METHODS: Randomized study included 23 scheduled patients operated upon due to cardiovascular diseases. Cardiac index (CI) was measured Comparative analyses of esCCO and others CO measurement methods used intraoperative was carried out. In the first group (n = 9) esCCO was compared with transpulmonary thermodilution (PiCCO-plus); in the second group (n = 8) - with pulmonary artery thermodilution; in the third group (n = 6) - with transoesophageal echocardiography (velocity-time integral)...
September 2017: Anesteziologiia i Reanimatologiia
https://www.readbyqxmd.com/read/29464927/microbial-lipid-extraction-from-lipomyces-starkeyi-using-irreversible-electroporation
#7
Ahasanul Karim, Abu Yousuf, M Amirul Islam, Yasir H Naif, Che Ku Mohammad Faizal, Md Zahangir Alam, Domenico Pirozzi
The aim of the study was to investigate the feasibility of using irreversible electroporation (EP) as a microbial cell disruption technique to extract intracellular lipid within short time and in an eco-friendly manner. An EP circuit was designed and fabricated to obtain 4 kV with frequency of 100 Hz of square waves. The yeast cells of Lipomyces starkeyi (L. starkeyi) were treated by EP for 2-10 min where the distance between electrodes was maintained at 2, 4 and 6 cm. Colony forming units (CFU) were counted to observe the cell viability under the high voltage electric field...
February 21, 2018: Biotechnology Progress
https://www.readbyqxmd.com/read/29463832/frequency-of-early-vascular-aging-and-associated-risk-factors-among-an-adult-population-in-latin-america-the-optimo-study
#8
Fernando Botto, Sebastian Obregon, Fernando Rubinstein, Angelo Scuteri, Peter M Nilsson, Carol Kotliar
The main objective was to estimate the frequency of early vascular aging (EVA) in a sample of subjects from Latin America, with emphasis in young adults. We included 1416 subjects from 12 countries in Latin America who provided information about lifestyle, cardiovascular risk factors (CVRF), and anthropometrics. We measured pulse wave velocity (PWV) as a marker of arterial stiffness, and blood pressure (BP) using an oscillometric device (Mobil-O-Graph). To determine the frequency of EVA, we used multiple linear regression to estimate each subject's PWV expected for his/her age and systolic BP, and compared with observed values to obtain standardized residuals (z-scores)...
February 20, 2018: Journal of Human Hypertension
https://www.readbyqxmd.com/read/29461604/a-novel-ultrasound-based-vascular-calcification-score-calcs-to-detect-subclinical-atherosclerosis
#9
R Flore, M A Zocco, M E Ainora, C Fonnesu, A Nesci, A Gasbarrini, F R Ponziani
OBJECTIVE: To quantify non-coronary vascular calcifications (VC) in asymptomatic patients at low-intermediate cardiovascular risk by a new color Doppler ultrasound (DUS)-based score (the carotid, aortic, lower limbs calcium score, CALCs), and to correlate this score with classical parameters associated with cardiovascular risk [carotid intima media thickness (IMT), and arterial stiffness (AS)]. PATIENTS AND METHODS: All consecutive asymptomatic patients who underwent a screening DUS of non-coronary circulation were evaluated and patients at low-intermediate cardiovascular risk were selected according to Framingham risk score (FRS)...
February 2018: European Review for Medical and Pharmacological Sciences
https://www.readbyqxmd.com/read/29460973/towards-an-analytic-solution-for-pulsed-cest
#10
Daniel F Gochberg, Mark D Does, Zhongliang Zu, Christopher L Lankford
Chemical exchange saturation transfer (CEST) is an imaging method based on magnetization exchange between solutes and water. This exchange generates changes in the measured signal after off-resonance radiofrequency irradiation. Although the analytic solution for CEST with continuous wave (CW) irradiation has been determined, most studies are performed using pulsed irradiation. In this work, we derive an analytic solution for the CEST signal after pulsed irradiation that includes both short-time rotation effects and long-time saturation effects in a two-pool system corresponding to water and a low-concentration exchanging solute pool...
February 20, 2018: NMR in Biomedicine
https://www.readbyqxmd.com/read/29460495/association-between-sleep-disordered-breathing-and-arterial-stiffness-in-heart-failure-patients-with-reduced-or-preserved-ejection-fraction
#11
Satoshi Suzuki, Akiomi Yoshihisa, Yu Sato, Shunsuke Watanabe, Tetsuro Yokokawa, Takamasa Sato, Masayoshi Oikawa, Atsushi Kobayashi, Takayoshi Yamaki, Hiroyuki Kunii, Kazuhiko Nakazato, Hitoshi Suzuki, Shu-Ichi Saitoh, Takafumi Ishida, Yasuchika Takeishi
AIMS: Sleep-disordered breathing (SDB) is associated with arterial stiffness, which may be one of the factors that lead to heart failure (HF). We examined the relationship between pulse wave velocity (PWV) and SDB in patients who have HF with reduced ejection fraction (HFrEF) and HF with preserved ejection fraction (HFpEF). METHODS AND RESULTS: We measured the apnoea-hypopnoea index (AHI) by polysomnography, echocardiographic parameters, and PWV in 221 HF patients...
February 20, 2018: ESC Heart Failure
https://www.readbyqxmd.com/read/29458701/impact-of-arterial-stiffness-on-watchpat-variables-in-patients-with-obstructive-sleep-apnea
#12
Taku Kinoshita, Misuzu Yahaba, Jiro Terada, Takuma Matsumura, Yoriko Sakurai, Kengo Nagashima, Seiichiro Sakao, Koichiro Tatsumi
STUDY OBJECTIVES: The WatchPAT is a wrist-worn portable device that creates integration data regarding peripheral arterial tone (PAT), oxyhemoglobin saturation, heart rate, and actigraphy to diagnose or screen for obstructive sleep apnea (OSA). Previous studies have demonstrated the efficacy and validity of respiratory variables measured by the WatchPAT compared to those using polysomnography (PSG). However, the effects of arterial stiffness or atherosclerosis on WatchPAT parameters remain to be elucidated...
February 13, 2018: Journal of Clinical Sleep Medicine: JCSM: Official Publication of the American Academy of Sleep Medicine
https://www.readbyqxmd.com/read/29457265/the-role-of-type-2-diabetes-mellitus-on-hypertensive-related-aortic-stiffness
#13
Edoardo Sciatti, Enrico Vizzardi, Assunta Castiello, Francesca Valentini, Ivano Bonadei, Sandro Gelsomino, Roberto Lorusso, Marco Metra
BACKGROUND: Hypertension is strongly related to arterial stiffness in a cause-effect fashion. Diabetes mellitus is also thought to determine vascular damage, mostly by means of advanced glycosylation end-products (AGEs). Aim of our study was to study the role of type 2 diabetes mellitus (T2DM) as regard ascending aortic elastic properties in hypertensive patients. METHODS: We prospectively enrolled outpatients with hypertension (n = 99) and type 2 diabetes mellitus plus hypertension (n = 42) without cardiovascular events...
February 19, 2018: Echocardiography
https://www.readbyqxmd.com/read/29456213/association-of-serum-fibroblast-growth-factor-23-with-doppler-pulse-wave-velocity-in-hemodialysis-patients
#14
Walaa H Ibrahim, Ahmad B Ahmad, Noha G Sayed
We aimed to study the association of fibroblast growth factor-23 (FGF-23) as a novel cardiovascular risk factor with Doppler pulse wave velocity (PWV) as an arterial stiffness measuring tool in hemodialysis (HD) patients. We conducted a cross-sectional study in which blood samples from 86 HD patients were obtained to estimate FGF 23 and other parameters. Flow waveforms were obtained at two locations within right common carotid artery, and right femoral artery by Doppler ultrasound with ECG recorded in addition...
January 2018: Saudi Journal of Kidney Diseases and Transplantation
https://www.readbyqxmd.com/read/29455431/menstrual-phase-and-the-vascular-response-to-acute-resistance-exercise
#15
Jacqueline A Augustine, Kayla N Nunemacher, Kevin S Heffernan
INTRODUCTION: Aerobic exercise has a favorable effect on systemic vascular function, reducing both central (large elastic artery) and peripheral (smaller muscular artery) stiffness. The effects of resistance exercise (RE) on arterial stiffness are more complex. Acute RE increases central artery stiffness while decreasing peripheral stiffness. To date, the majority of studies have been performed in predominantly male participants. PURPOSE: To examine the effect of acute RE on central and peripheral arterial stiffnesses in women, a secondary purpose was to explore the influence of cyclic changes in estrogen status across the menstrual cycle on the arterial response to acute RE...
February 17, 2018: European Journal of Applied Physiology
https://www.readbyqxmd.com/read/29455200/cardiovascular-and-patient-phenotype-of-extended-haemodialysis-a-critical-analysis-of-studying-a-unique-patient-population
#16
Nicos Mitsides, Tom Cornelis, Natascha J H Broers, Nanda M P Diederen, Paul Brenchley, Frank M van der Sande, Casper Schalkwijk, Jeroen P Kooman, Sandip Mitra
BACKGROUND: Extended haemodialysis (EHD) has been associated with better outcomes compared to conventional (CHD) regimes. The cardiovascular (CV) profile of these patients has not been assessed in detail. METHODS: We report baseline demographic and CV phenotype of 36 CHD and 36 EHD participants to a longitudinal multicentre study. We measured pulse wave velocity (PWV), 24-h ambulatory blood pressure, sublingual dark-field capillaroscopy and vascular biomarkers. RESULTS: EHD patients were younger (p < 0...
February 16, 2018: Blood Purification
https://www.readbyqxmd.com/read/29453675/evaluation-of-carotid-artery-elasticity-in-patients-with-uremia-by-echo-tracking
#17
Hong Liang, Dawei Wang, Guoying Che, Yanxin Su
PURPOSE: The purpose of this study was to compare the carotid artery wall elasticity between patients with uremia and controls using echo tracking (ET). METHODS: Ninety-three patients with uremia and 35 control subjects (Group A) were enrolled in this study. In the ET mode, the carotid artery elasticity parameters including stiffness index (β), pressure-strain elasticity modulus (EP), arterial compliance (AC), and one-point pulse wave velocity (PWVβ) were measured, and carotid intima-media thickness (IMT) was measured with B-mode ultrasonography...
February 16, 2018: Journal of Medical Ultrasonics
https://www.readbyqxmd.com/read/29452601/reactive-hyperemia-index-rhi-and-cognitive-performance-indexes-are-associated-with-histologic-markers-of-liver-disease-in-subjects-with-non-alcoholic-fatty-liver-disease-nafld-a-case-control-study
#18
Antonino Tuttolomondo, Salvatore Petta, Alessandra Casuccio, Carlo Maida, Vittoriano Della Corte, Mario Daidone, Domenico Di Raimondo, Rosaria Pecoraro, Roberto Fonte, Anna Cirrincione, Rita Zafonte, Daniela Cabibi, Calogero Cammà, Vito Di Marco, Anna Licata, Franco Magliozzo, Giulio Marchesini, Giovanni Merlino, Antonio Craxì, Antonio Pinto
BACKGROUND: No study evaluated vascular health markers in subjects with non-alcoholic fatty liver disease (NAFLD) through a combined analysis of reactive hyperemia peripheral arterial tonometry (RH-PAT) and arterial stiffness indexes. AIM OF THE STUDY: We aimed to assess whether NAFLD and its histological severity are associated with impairment of arterial stiffness and RH-PAT indexes in a mixed cohort of patients with biopsy-proven NAFLD. MATERIALS AND METHODS: The Kleiner classification was used to grade NAFLD grade...
February 16, 2018: Cardiovascular Diabetology
https://www.readbyqxmd.com/read/29452335/change-in-cardiometabolic-risk-among-blacks-whites-and-hispanics-findings-from-the-health-and-retirement-study
#19
Uchechi A Mitchell, Jennifer A Ailshire, Eileen M Crimmins
Background: Blacks experience greater multi-system physiological dysregulation, or cumulative biological risk, which is associated with poor cardiometabolic health and mortality. In this study, we assess race differences in change in risk over four years among older whites, blacks and Hispanics. Method: We examined race differences in 4-year change in individual biomarkers and a cumulative measure of risk-cardiometabolic risk (CMR)-using data for each respondent from two waves of the Health and Retirement Study's biomarker assessment (n=5,512)...
February 14, 2018: Journals of Gerontology. Series A, Biological Sciences and Medical Sciences
https://www.readbyqxmd.com/read/29451817/the-impact-of-pulse-pressure-on-cerebrovascular-events-leading-to-age-related-cognitive-decline
#20
Nathalie Thorin-Trescases, Olivia de Montgolfier, Anthony Pinçon, Adeline Raignault, Laurie Caland, Pauline Labbé, Eric Thorin
Aging is a modern concept: human life expectancy has more than doubled in less than 150 years in Western countries. Longer lifespan, however, reveals age-related diseases, including cerebrovascular diseases. The vascular system is a prime target of aging: the "wear and tear" of large elastic arteries exposed to a life-long pulsatile pressure causes arterial stiffening by fragmentation of elastin fibers and replacement by stiffer collagen. This arterial stiffening increases in return the amplitude of the pulse pressure (PP), its wave penetrating deeper into the microcirculation of low resistance, high flow organs such as the brain...
February 16, 2018: American Journal of Physiology. Heart and Circulatory Physiology
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