Phys Rev Lett
October 2019
We report on the theoretical model and experimental results of the experiment made in a limit of absolute zero temperature (∼600 μK) studying the spin wave analog of black- and white-hole horizons using spin (magnonic) superfluidity in superfluid ^{3}He-B. As an experimental tool simulating the properties of the black- and white-hole horizons, we used the spin-precession waves propagating on the background of the spin supercurrents between two Bose-Einstein condensates of magnons in the form of homogeneously precessing domains. We provide experimental evidence of the white hole formation for spin precession waves in this system, together with the observation of an amplification effect.
View Article and Find Full Text PDFIncreases in resting energy expenditure (REE) likely contribute to weight loss in various chronic diseases. In chronic obstructive pulmonary disease (COPD), relationships between the ventilatory impairment and increased REE, and between disturbances in adipokines and weight loss were previously described. Therefore, we investigated serum levels and adipose tissue expression of leptin and adiponectin, and their relationships to REE in patients with COPD.
View Article and Find Full Text PDFRecently we observed increased adipose tissue (AT) expression of CD40-related signaling proteins but no activation of tumor necrosis factor-α or CD68 in patients with chronic sustained hypoxia resulting from chronic obstructive pulmonary disease (COPD). Transcription factor nuclear factor-κB (NFκB) is involved in cellular responses to hypoxia and activates the proinflammatory gene expression with concomitant upregulation of its own repressors--inhibitors of κB (IκB) in an auto feedback loop. Inhibitor of kappaB kinase (IKK)-γ and inhibitor of kappaB kinase complex-associated protein (IKAP) are further regulatory proteins involved in NFκB signaling.
View Article and Find Full Text PDFA principle of operation and electrical characteristics of a high frequency current-to-voltage (I/V) converter are presented. The I/V converter measures the electric current with selectable gains of 10(5), 10(4), and 10(3) V/A in the frequency range from DC to 500 kHz, 1.2 MHz, and 2.
View Article and Find Full Text PDFObjective: Chronic obstructive pulmonary disease (COPD) is associated with increased cardiovascular morbidity and mortality. Several large population-based cohort studies identified an association between reduced lung function and increased intima-media thickness (IMT). Nevertheless, a vast majority of subjects in these studies did not suffer from COPD and thus it remains unclear whether IMT differs among various stages of COPD severity.
View Article and Find Full Text PDFIntroduction: The role of fat-bone interactions in the pathogenesis of osteoporosis in chronic obstructive pulmonary disease (COPD) is poorly understood. Our aim was to investigate expressions of leptin and osteoprotegerin (OPG) in the adipose tissue, and their relationships to osteoporosis in patients with COPD.
Methods: In 39 patients with stable COPD, bone mineral density (BMD) and body composition was assessed by Dual Energy X-Ray Absorptiometry.
Potential links between metabolic derangements and adipose tissue (AT) inflammation in patients with chronic obstructive pulmonary disease (COPD) are unexplored. We investigated AT expressions of interleukin (IL)-6, tumor necrosis factor (TNF)-α, CD68 (macrophage cell surface receptor), caspase-3, and Bax, and their relationships to the metabolic phenotype in nine cachectic, 12 normal-weight, 12 overweight, and 11 obese patients with COPD (age 62.3 ± 7.
View Article and Find Full Text PDFWhen immersed in liquid 3He, the nanometer strands of aerogel are coated with a thin layer of solid 3He, forming a network of irregular nanotubes. Owing to its high purity and weak interactions, this system is ideal for studying fundamental processes. We report the first experiments on solid 3He in aerogel at ultralow temperatures, cooled by direct adiabatic demagnetization.
View Article and Find Full Text PDFBackground: CD40, a transmembrane receptor of the tumor necrosis factor gene superfamily, is activated in response to cellular stress, including hypoxia, and orchestrates the process of inflammation via secondary messengers such as mitogen-activated protein kinase kinase 4 (MKK4) and c-Jun NH(2)-terminal kinases (JNK).
Objectives: We hypothesized that CD40, MKK4 and JNK expression is increased in the adipose tissue of patients with very severe chronic obstructive pulmonary disease (COPD).
Methods: In 20 patients with stable COPD, lung function was assessed using body plethysmography, and samples of subcutaneous adipose tissue were analyzed using real-time PCR.
Background: Knowledge of the effects of undernourishment on the severity of respiratory impairment, systemic inflammation and oxidative stress during acute exacerbations of COPD (AECOPD) is limited. In patients with AECOPD, we assessed the relationships between BMI, lung function, and markers of systemic inflammation and oxidative stress.
Material/methods: We measured pulmonary function, serum C-reactive protein (CRP), tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, IL-8, malondialdehyde (MDA), erythrocytic glutathione-peroxidase (GPx), superoxiddismutase (SOD), and catalase (CAT) in 113 patients admitted to the hospital due to an AECOPD (80 males, age 66.
Bose-Einstein condensation of magnons in superfluid 3He-B is experimentally manifested by various states where coherent spin precession is established spontaneously, even in nonhomogeneous magnetic fields. Once such a condensate with coherent spin precession is created, it occupies the state with minimal energy, the ground state. The application of an additional magnetic field to that condensate may cause its deflection from the energy minimum and the condensate responds by creating collective gapless oscillations known as Goldstone modes.
View Article and Find Full Text PDFAim: To determine the risk of chronic obstructive pulmonary disease (COPD) associated with polymorphisms in the glutathione S-transferase (GST) M1, GST T1, and microsomal epoxide hydrolase (EPHX1) genes in a cohort of Slovak population.
Methods: Two hundred and seventeen patients with the diagnosis of COPD and 160 control subjects were enrolled in the study. Blood samples were collected from all subjects and the DNA from peripheral blood lymphocytes was used for subsequent genotyping assays, using polymerase chain reaction and restriction fragment-length polymorphism methods.
In some applications, like a magnetization and demagnetization of ordinary and superconducting magnets driven by the voltage controlled current sources, it is desirable to change the voltage smoothly and linearly toward an adjusted value and then hold this value in time. A circuit is presented that allows: (i) the slow, smooth, and linear change of the integrator output voltage without steps and (ii) the ability to hold the output voltage at a value given by a reference source. In a hold regime, the output voltage is stabilized by a negative feedback.
View Article and Find Full Text PDFSympathetic activation and parasympathetic withdrawal are commonly observed during acute exacerbations of chronic obstructive pulmonary disease (COPD). We have demonstrated previously that noninvasive positive-pressure ventilation (NPPV) improves parasympathetic neural control of heart rate in patients with obstructive sleep apnea. We hypothesized that NPPV may exert such beneficial effects in COPD as well.
View Article and Find Full Text PDFWe have measured the surface energy of the interface between the A and B phases of superfluid 3He in the low temperature limit at zero pressure. Using a shaped magnetic field, we control the passage of the phase boundary through a small aperture. We obtain the interphase surface energy from the over- or undermagnetization required to force the interface through the aperture in both directions, yielding values of the surface tension and the interfacial contact angle.
View Article and Find Full Text PDFSpin precession waves of homogeneously precessing domains (HPD) in superfluid 3He-B have been studied at 11 bars and temperatures down to 0.45T(c). The waves were excited by an alternating longitudinal magnetic field with an axial symmetry, applied as a small perturbation ranging from 1 nT up to a few micro T.
View Article and Find Full Text PDFWe have studied nucleation in superfluid 3He across the A-B phase transition driven by a magnetic field, in a controllable environment at very low temperatures. Both B-->A and A-->B secondary nucleation appear to be governed by the survival of pockets of the new phase trapped at surfaces. We find that, at fields near B(AB), primary A-->B nucleation cannot be triggered by ionizing or neutron irradiation even at very high intensities.
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