Classical fields approximation for cold weakly interacting bosons without free parameters

Classical fields approximation to cold weakly interacting bosons allows for a unified treatment of condensed and uncondensed parts of the system. Until now, however, the quantitative predictions were limited by a dependence of the results on a grid chosen for numerical implementation of the method. In this paper we propose replacing this unphysical ambiguity by an additional postulate: the temperature of the gas at thermal equilibrium should be the same as that of an ideal Bose gas with the same fraction of condensed atoms. As it turns-out, with this additional assumption, nearly all atoms are within the classical fields, thus the method applies to the whole system

Application of a self-expanding stent in the treatment of subclavian artery occlusion — a case study

Istotne zwężenie lub całkowita niedrożność tętnicy podobojczykowej jest stosunkowo rzadkim schorzeniem, występuje w około 0,4% populacji. W 90% przypadków przyczyną niedrożności lub zwężenia tętnicy podobojczykowej jest miażdżyca. Niedrożność lub hemodynamicznie istotne zwężenie (> 70%) może prowadzić do rozwoju objawów w postaci niedokrwienia mózgu lub niedokrwienia kończyny górnej. Zwężenie tętnicy podobojczykowej może być leczone zarówno metodami klasycznej chirurgii, jak i z zastosowaniem technik wewnątrznaczyniowych. W związku z porównywalnymi wynikami pierwotnej drożności a mniejszym ryzykiem samego zabiegu, techniki wewnątrznaczyniowe są obecnie leczeniem z wyboru zwężenia lub niedrożności tętnicy podobojczykowej. W prezentowanej pracy przedstawiono przypadek zastosowania samorozprężalnego stentu Misago (Terumo), należącego do nowej generacji obwodowych stentów samorozprężalnych opartych na systemie monorailowym (RX), w leczeniu długiej, 7-centymetrowej zmiany w proksymalnym odcinku lewej tętnicy podobojczykowej. Zdaniem autorów długoodcinkowe zmiany wymagają zastosowania stentu elastycznego, odpornego na zgięcie czy załamanie. Stent Misago (Terumo) może być z powodzeniem wykorzystany w wewnątrznaczyniowym leczeniu pozaostialnych zmian tętnicy podobojczykowej. Chirurgia Polska 2011, 13, 1, 75–82Significant stenosis or complete SA subclavian artery occlusion is a relatively rare illness; it occurs in about 0.4% of the population. In 90% of cases atherosclerosis is the cause of subclavian artery (SA) occlusion or stenosis. Occlusion or hemodynamically significant stenosis (> 70%) may lead to the development of symptoms in the form of cerebral ischaemia or upper limb ischaemia. SA stenosis can be treated by both classical techniques and with the use of endovascular techniques. In connection with comparable results of the primary patency and a lower risk of the procedure itself, endovascular techniques are at present the primary treatment of SA stenosis or occlusion. In the presented paper the case of application of the MISAGO (Terumo) self-expanding stent, belonging to the new generation of peripheral self-expanding stents based on a monorail system, in the treatment of a 7 cm long lesion in the proximal left subclavian artery is presented. In the authors’ opinion, long-section lesions require the use of a flexible stent resistant to bending or deflection. The Misago (Terumo) stent can be successfully used in endovascular treatment of extra-ostial lesions of the subclavian artery. Polish Surgery 2011, 13, 1, 75–8

Superfluidity of the BEC at finite temperature

We use the classical fields approximation to study a translational flow of the condensate with respect to the thermal cloud in a weakly interacting Bose gas. We study both, subcritical and supercritical relative velocity cases and analyze in detail a state of stationary flow which is reached in the dynamics. This state corresponds to the thermal equilibrium, which is characterized by the relative velocity of the condensate and the thermal cloud. The superfluidity manifests itself in the existence of many thermal equilibria varying in (the value of this velocity) the relative velocity between the condensate and the thermal cloud. We pay a particular attention to excitation spectra in a phonon as well as in a particle regime. Finally, we introduce a measure of the amount of the superfluid fraction in a weakly interacting Bose gas, allowing for the precise distinction between the superfluid and the condensed fractions in a single and consistent framework.Comment: 8 pages, 5 figure

Difficulties in diagnosis of aortobifemoral graft infection

Wraz ze wzrostem liczby operacji naczyniowych wzrasta także liczba powikłań. Infekcje protezy naczyniowej (VGI) należą do najcięższych powikłań w chirurgii naczyniowej. Celem pracy jest przedstawienie trudności w ustaleniu rozpoznaniu zakażenia protezy naczyniowej, pomimo stosowania różnych technik obrazowania, z uwzględnieniem rezonansu magnetycznego (MRI), tomografii komputerowej (TK) i scyntygrafii leukocytami znakowanymi technetem-99 (99mTC-HMPAO). W diagnostyce VGI nadal brakuje powszechnie dostępnych, skutecznych metod, pozwalających potwierdzić rozpoznanie w trudnych przypadkach. Możliwe, że upowszechnienie nowoczesnych metod diagnostyki, takich jak PET/SPECT/TK, przyczyni się do zwiększenia skuteczności rozpoznawania infekcji protez naczy­niowych, zwłaszcza w dobie coraz większego upowszechnienia zabiegów wewnątrznaczyniowych, które także nie są wolne od ryzyka infekcji.The number of complications increases together with the growing number of vascular procedures. Vascular graft infection (VGI) still remains the most serious complication in vascular surgery. The purpose of this report is to present the difficulties in vascular prosthesis infection diagnostics despite the use of various diagnostic methods, including magnetic resonance imaging (MRI), computed tomo­graphy (CT) and Technetium-99m —labeled leukocyte scan (99mTC-HMPAO). It is possible that the spread of modern diagnostic methods, such as PET/SPECT/CT will help to increase the diagnostic efficiency of vascular graft infections, especially in the era of ever- increasing number of endovascular procedures, which also carry the risk of infection

Classical fields method for a relativistic interacting Bose gas

We formulate a classical fields method for description of relativistic interacting bosonic particles at nonzero temperatures. The method relays on the assumption that at low temperatures the Bose field can be described by a c-number function. We discuss a very important role of the cut-off momentum which divides the field into dominant classical part and a small quantum correction. We illustrate the method by studying a thermodynamics of relativistic Bose field which dynamics is governed by the Klein-Gordon equation with $\lambda \psi^4$ term responsible for interactions.Comment: 12 pages, 10 figure

Probing the classical field approximation - thermodynamics and decaying vortices

We review our version of the classical field approximation to the dynamics of a finite temperature Bose gas. In the case of a periodic box potential, we investigate the role of the high momentum cut-off, essential in the method. In particular, we show that the cut-off going to infinity limit decribes the particle number going to infinity with the scattering length going to zero. In this weak interaction limit, the relative population of the condensate tends to unity. We also show that the cross-over energy, at which the probability distribution of the condensate occupation changes its character, grows with a growing scattering length. In the more physical case of the condensate in the harmonic trap we investigate the dissipative dynamics of a vortex. We compare the decay time and the velocities of the vortex with the available analytic estimates.Comment: 7 pages, 8 eps figures, submitted to J. Optics B for the proceedings of the "Atom Optics and Interferometry" Lunteren 2002 worksho

Thermodynamics of an interacting trapped Bose-Einstein gas in the classical field approximation

We present a convenient technique describing the condensate in dynamical equilibrium with the thermal cloud, at temperatures close to the critical one. We show that the whole isolated system may be viewed as a single classical field undergoing nonlinear dynamics leading to a steady state. In our procedure it is the observation process and the finite detection time that allow for splitting the system into the condensate and the thermal cloud.Comment: 4 pages, 4 eps figures, final versio

Novel inflammatory biomarkers may reflect subclinical inflammation in young healthy adults with obesity

Introduction: Obesity is often accompanied by low-grade inflammation. In recent years a few blood-based inflammatory markers — neutrophil-to-lymphocyte ratio (NLR), derived neutrophil-to-lymphocyte ratio (dNLR), platelet-to-lymphocyte ratio (PLR), lymphocyteto-monocyte ratio (LMR), and monocyte-to-high-density lipoprotein ratio (MHR) — have been identified. They have been proven to correlate well with established inflammatory markers such as hsCRP and have a prognostic value among others in patients with coronary artery disease, heart failure, and malignancies. The aim of the study was to find markers associated with obesity in young heathy adults. Material and methods: The study group included 321 young healthy adults aged 18-35 years (210 males and 111 females). Partial least squares regression analysis was used to find variables associated with body mass index (BMI). Analysed variables included complete blood count, lipid profile, sex hormone levels, acute-phase protein levels, and blood-based inflammatory markers. Results: Variables with the strongest association with BMI in the group of men were HDL% and apolipoprotein B, and in the group of women, HDL, HDL%, triglycerides, and MHR. Novel inflammatory markers were not associated with BMI, except MHR. We found significant (p < 0.001) correlations between novel biomarkers (NLR, dNLR) and hsCRP and fibrinogen levels in the group of subjects with obesity. Conclusions: Blood-based inflammatory markers significantly correlate with hsCRP and fibrinogen in young healthy adults with obesity, which may reflect the subclinical inflammation in this group of individuals

From a nonlinear string to a weakly interacting Bose gas

We investigate a real scalar field whose dynamics is governed by a nonlinear wave equation. We show that classical description can be applied to a quantum system of many interacting bosons provided that some quantum ingredients are included. An universal action has to be introduced in order to define particle number. The value of this action should be equal to the Planck constant. This constrain can be imposed by removing high frequency modes from the dynamics by introducing a cut-off. We show that the position of the cut-off has to be carefully adjusted. Finally, we show the proper choice of the cut-off ensures that all low frequency eigenenmodes which are taken into account are macroscopically occupied.Comment: 7 pages, 4 figure

FUNCTIONAL NEUROMARKERS OF POST-TRAUMATIC STRESS DISORDER (PTSD) IN A MAJOR ISCHEMIC STROKE SURVIVOR AFTER CAROTID ENDARTERECTOMY (CEA) REVASCULARIZATION

The aim of this study was to test the hypothesis of developing Post-Traumatic Stress Disorder (PTSD) in a major right-hemisphere ischemic brain stroke survivor half a year after CEA revascularization, with the use of Event Related Potentials (ERPs). He was in a serious condition and had limited consciousness. Therefore, the doctor informed the patient's wife about the possibility of sudden death. The patient heard this information and remembered it, which was one of the main causes of the development of PTSD. On the basis of previous research amplitudes of P3 ERP, components elicited in the cued GO/NOGO tasks have been chosen as the candidate for PTSD neuromarkers . A 44-year-old patient had a major ischemic brain stroke while sizeable atherosclerotic plaque causing critical stenosis of the internal carotid artery in Angio-CT was dioscovered. The patient was urgently operated on using CEA. After the operation he had the opportunity to see the removed plaque which had been the cause of his stroke. Despite the positive postoperative recovery, half a year later, the patient began to complain of flashbacks, anxiety, trouble in falling and staying asleep, difficulty in concentration, a loss of interest. For the diagnosis of PTSD we used Checklist Specific for a stressor (PCL-S). Additionally we used Checklist according to the Diagnostic Statistical Manual-5 (DSM-5) classification, and the patient met the PTSD criteria. The cognitive profile of the patient was measured with the use of the Wechsler Memory Test – III (WMS-III). Subsequently, the patient participated in the cued GO/NOGO task (Kropotov, 2009) with a recording 19-channel EEG. The P3 GO and NOGO waves in this task were found to be significantly smaller at p<0.01 in comparison to a group of healthy control subjects of the same age (N=23) taken from the Human Brain Institute (HBI) normative database (https://www.hbimed.com/). The pattern of this neuromarker in our patient corresponds to the ERPs pattern found in PTSD patients. The ERPs in a GO/NOGO task can be used in the assessment of the functional brain changes induced by chronic PTSD