1,450 research outputs found
Parametry morfologiczne tętnic obwodowych w ocenie ryzyka sercowo-naczyniowego
Introduction. The aim of the study was to test the hypothesis that ultrasound measurements of common carotid artery (CCAd) and brachial artery (BAd) diameters represent markers of higher coronary artery disease risk (CAD, defined as ≥ 50% reduction in diameter of at least one large coronary artery segment).
Materials and methods. Seventy-one patients (pts) evaluated for suspected stable CAD (23.9% women, age 61.5 ± 7.5) underwent ultrasound measurements of averaged diameters of both common carotid arteries and the brachial artery diameter of dominant arm. Clinical protocol included also: standard medical examination, assessment of biochemical parameters, resting electrocardiography, treadmill exercise test and transthoracic echocardiography. Diagnosis was established using quantitative coronary angiography measurements and calculation of Gensini Score (GS).
Results. Angiographic CAD was present in 43 (60.5%) patients. Average CCAd was larger in CAD group (7.97 ± 0.96 mm vs. 7.37 ± 0.67 mm, p = 0.0052), similar to BAd (5.06 ± 0.65 vs. 4.68 ± 0.75, p = 0.03), respectively. The peripheral arterial diameters correlated with values of GS index, more pronounced for CCAd (ρ = 0.35, p = 0.0023) than for BAd (ρ = 0.24, p = 0.0368). CCAd significantly more positively correlated with the distal coronary artery segments values of the GS index (ρ = 0.35, p = 0.0024), whereas the diameter of BA with the proximal segments values of GS index (ρ = 0.239, p = 0.045). CCA and BD diameters indexed to body surface area (BSA) showed a strong trend toward larger average diameters in CAD patients: CCAd/BSA index: 4.06 ± 0.46 mm/m2 vs. 3.85 ± 0.56 mm/m2, p = 0.087, BAd/BSA
index: 2.57 ± 0.29 mm/m2 vs. 2.42 ± 0.35 mm/m2, p = 0.057. Gensini score significantly correlated with CCAd/BSA index (ρ = 0.24, p = 0.043) with a strong trend of positive correlation between GS index and BAd/BSA index (ρ = 0.21, p = 0.076).
Conclusions. The diameters of common carotid arteries and the brachial artery of dominant arm are greater in CAD pts. Peripheral arteries ultrasound may complement classic diagnostic pathway of stable coronary artery disease.Wstęp. Celem badania była weryfikacja hipotezy, czy ultrasonograficzny pomiar średnic tętnic szyjnych wspólnych (CCAd) i tętnicy ramiennej (BAd) może stanowić marker zwiększonego ryzyka wystąpienia choroby wieńcowej (CAD), definiowanej jako zwężenie większe lub równe 50% średnicy co najmniej jednego segmentu dużej tętnicy wieńcowej.
Materiały i metody. Diagnozowanych w kierunku choroby wieńcowej 71 pacjentów (23,9% kobiet, średni wiek 61,5 ± 7,5) poddano ultrasonograficznej ocenie średnic obu tętnic szyjnych wspólnych i tętnicy ramiennej dominującej kończyny górnej. Protokół badania obejmował również ocenę kliniczną, ocenę wskaźników biochemicznych, spoczynkowy zapis elektrokardiograficzny, elektrokardiograficzny test wysiłkowy, przezklatkowe badanie echokardiograficzne, z weryfikacją wyników w koronarografii i oceną zmian w naczyniach wieńcowych metodą cyfrowej angiografii ilościowej i wyliczeniem wskaźnika Gensiniego (GS).
Wyniki. Obecność istotnych zwężeń w koronarografii stwierdzono u 43 (60,5%) pacjentów. Średnia wartość CCAd była większa u pacjentów z CAD (7,97 ± 0,96 mm vs. 7,37 ± 0,67 mm; p = 0,0052), podobnie jak wartość BAd (5,06 ± 0,65 vs. 4,68 ± 0,75; p = 0,03). Wartości średnic tętnic obwodowych korelowały ze wskaźnikiem GS bardziej wyraźnie w przypadku CCAd (ρ = 0,35; p = 0,0023) niż dla BAd (ρ = 0,24; p = 0,0368). Wartości CCAd znacząco wyraźniej dodatnio korelowały z dystalnymi segmentami (ρ = 0,35; p = 0,0024), natomiast średnica BA — z proksymalnymi segmentami tętnic wieńcowych ocenianych według GS (ρ = 0,239; p = 0,045). Po zastosowaniu metody indeksacji do pola powierzchni ciała (BSA) stwierdzono obecność silnego trendu w kierunku wyższych wartości średnic badanych tętnic obwodowych wśród pacjentów z chorobą wieńcową — wskaźnik CCAd/BSA: 4,06 ± 0,46 mm/m2 vs. 3,85 ± 0,56 mm/m2, p = 0,087, wskaźnik BAd/BSA: 2,57 ± 0,29 mm/m2 vs. 2,42 ± 0,35 mm/m2, p = 0,057. Wskaźnik Gensiniego znacząco korelował z indeksem CCAd/BSA (ρ = 0,24; p = 0,043) oraz wykazano dodatni trend w korelacji między wskaźnikiem GS i indeksem BAd/BSA (ρ = 0,21; p = 0,076).
Wnioski. Średnice tętnic szyjnych wspólnych i średnicy ramiennej dominującej kończyny górnej są większe u pacjentów z CAD. Ultrasonografia tętnic obwodowych może stanowić uzupełniającą metodę w diagnostyce CAD
A room temperature 19-channel magnetic field mapping device for cardiac signals
We present a multichannel cardiac magnetic field imaging system built in
Fribourg from optical double-resonance Cs vapor magnetometers. It consists of
25 individual sensors designed to record magnetic field maps of the beating
human heart by simultaneous measurements on a grid of 19 points over the chest.
The system is operated as an array of second order gradiometers using
sophisticated digitally controlled feedback loops.Comment: 3 pages, 3 figures, submitted to Applied Physics Letter
Harvesting, coupling and control of single exciton coherences in photonic waveguide antennas
We perform coherent non-linear spectroscopy of individual excitons strongly
confined in single InAs quantum dots (QDs). The retrieval of their
intrinsically weak four-wave mixing (FWM) response is enabled by a
one-dimensional dielectric waveguide antenna. Compared to a similar QD embedded
in bulk media, the FWM detection sensitivity is enhanced by up to four orders
of magnitude, over a broad operation bandwidth. Three-beam FWM is employed to
investigate coherence and population dynamics within individual QD transitions.
We retrieve their homogenous dephasing in a presence of spectral wandering.
Two-dimensional FWM reveals off-resonant F\"orster coupling between a pair of
distinct QDs embedded in the antenna. We also detect a higher order QD
non-linearity (six-wave mixing) and use it to coherently control the FWM
transient. Waveguide antennas enable to conceive multi-color coherent
manipulation schemes of individual emitters.Comment: 7 pages, 8 Figure
Structural polymorphism of the HIV-1 leader region explored by computational methods
Experimental studies revealed that the elements of the human immunodeficiency virus type 1 (HIV-1) 5′-untranslated leader region (5′-UTR) can fold in vitro into two alternative conformations, branched (BMH) and ‘linearized’ (LDI) and switch between them to achieve different functionality. In this study we computationally explored in detail, with our massively parallel genetic algorithm (MPGAfold), the propensity of 13 HIV-1 5′-UTRs to fold into the BMH and the LDI conformation types. Besides the BMH conformations these results predict the existence of two functionally equivalent types of LDI conformations. One is similar to what has been shown in vitro to exist in HIV-1 LAI, the other is a novel conformation exemplified by HIV-1 MAL long-distance interactions. These novel MPGAfold results are further corroborated by a consensus probability matrix algorithm applied to a set of 155 HIV-1 sequences. We also have determined in detail the impact of various strain mutations, domain sizes and folds of elongating sequences simulating folding during transcription on HIV-1 RNA secondary structure folding dynamics
Coherence dynamics and quantum-to-classical crossover in an exciton-cavity system in the quantum strong coupling regime
Interaction between light and matter generates optical nonlinearities, which are particularly pronounced in the quantum strong coupling regime. When a single bosonic mode couples to a single fermionic mode, a Jaynes-Cummings (JC) ladder is formed, which we realize here using cavity photons and quantum dot excitons. We measure and model the coherent anharmonic response of this strongly coupled exciton-cavity system at resonance. Injecting two photons into the cavity, we demonstrate a root 2 larger polariton splitting with respect to the vacuum Rabi splitting. This is achieved using coherent nonlinear spectroscopy, specifically four-wave mixing, where the coherence between the ground state and the first (second) rung of the JC ladder can be interrogated for positive (negative) delays. With increasing excitation intensity and thus rising average number of injected photons, we observe spectral signatures of the quantum-to-classical crossover of the strong coupling regime.Peer reviewe
Cellular expression of interleukin 2 (IL-2) and its receptor (IL-2R, CD25) in lung tumours
In view of the unclear prognostic and diagnostic role of interleukin 2 (IL-2) and its receptor in human tumours, we examined the cellular expression of IL-2 and of the subunit α of its receptor (IL-2Rα, CD25) in relation to the proliferative activity of various subtypes of lung tumours. The immunocytochemical ABC technique
was applied to archival tissue material of neuroendocrine lung tumours: lung carcinoids, including typical carcinoids (TC), atypical carcinoids (AC) and small-cell lung cancers (SCLC) and squamous cell lung cancers (non-small cell lung cancers, NSCLC). Expression of IL-2 was detected in all types of lung tumours. The highest frequency of IL-2 expression (93%) was noted and the most pronounced semi-quantitatively evaluated expression of IL-2 was detected in AC tumour cells. The expression was more pronounced as compared to neoplastic SCLC (p = 0.01) and NSCLC cells (p = 0.005). The results suggest a negative correlation between IL-2 expression and the proliferative activity of tumour cells (evaluated by expression of Ki-67) in AC. The frequency of detection of IL-2 receptor (IL-Rα, CD25) was the highest in NSCLC (94%). Semi-quantitative
expression of IL-2R, like that of IL-2, also dominated in the group of
atypical lung carcinoids but manifested a significant difference only as compared to typical carcinoids (p = 0.014). Within the groups of tumours studied no correlation could be detected between cellular expressions of IL-2 and IL-2R. Our results demonstrate variable expression of IL-2 and its receptor in various types of lung tumours, but no simple relationship could be detected between tissue expression of the markers and proliferative activity. Appraisal of the diagnostic and/or prognostic significance of the results requires further study
Micropillar resonator in a magnetic field: Zero and Finite temperature cases
In this work, we present a theoretical study of a quantum dot-microcavity
system which includes a constant magnetic field in the growth direction of the
micropillar. First, we study the zero temperature case by means of a
selfconsistent procedure with a trial function composed by a coherent photon
field and a BCS function for the electron-hole pairs. The dependence of the
ground-state energy on the magnetic field and the number of polaritons is
found. We show that the magnetic field can be used as a control parameter of
the photon number, and we make explicit the scaling of the total energy with
the number of polaritons. Next, we study this problem at finite temperatures
and obtain the scaling of the critical temperature with the number of
polaritons.Comment: "Paper presented in PLMCN7. To appear in Superlattices and
Microstructures
Antireflective photonic structure for coherent nonlinear spectroscopy of single magnetic quantum dots
This work presents epitaxial growth and optical spectroscopy of CdTe quantum
dots (QDs) in (Cd,Zn,Mg)Te barriers placed on the top of (Cd,Zn,Mg)Te
distributed Bragg reflector. The formed photonic mode in our half-cavity
structure permits to enhance the local excitation intensity and extraction
efficiency of the QD photoluminescence, while suppressing the reflectance
within the spectral range covering the QD transitions. This allows to perform
coherent, nonlinear, resonant spectroscopy of individual QDs. The coherence
dynamics of a charged exciton is measured via four-wave mixing, with the
estimated dephasing time ps. The same structure contains
QDs doped with single Mn ions, as detected in photoluminescence spectra.
Our work therefore paves the way toward investigating and controlling an
exciton coherence coupled, via ,- exchange interaction, with an
individual spin of a magnetic dopant.Comment: 6 pages, 5 figure
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