614 research outputs found

    Inviscid Large deviation principle and the 2D Navier Stokes equations with a free boundary condition

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    Using a weak convergence approach, we prove a LPD for the solution of 2D stochastic Navier Stokes equations when the viscosity converges to 0 and the noise intensity is multiplied by the square root of the viscosity. Unlike previous results on LDP for hydrodynamical models, the weak convergence is proven by tightness properties of the distribution of the solution in appropriate functional spaces

    Elastografia fali poprzecznej guzów nadnerczy jest możliwa do wykonania i może pomóc w różnicowaniu zmian litych z torbielowatymi — doniesienie wstępne

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    Introduction: The aim of this study was to evaluate the feasibility and usefulness of supersonic shear wave elastography (SSWE) in the diagnosis of nonmalignant adrenal masses.Material and methods: 13 patients with a total number of 16 adrenal masses were enrolled in the study. In each case, both conventional ultrasound imaging and SSWE for stiffness assessment were performed. The final diagnosis was based on CT, MRI, biochemical studies, surgery or more than one year of follow up.Results: The final diagnosis: nodular hyperplasia in six masses, six adenomas, three cysts, and one myelolipoma. All solid adrenal masses presented the elastography signal in contrast to cystic lesions that were devoid of it, as shear waves do not propagate through fluids.Conclusions: SSWE is a feasible technique that can be applied during ultrasound of the abdomen and retroperitoneum. SSWE presents potential for the differentiation of solid and cystic adrenal lesions. Further large scale studies evaluating the possibility of differentiation of adrenal and other retroperitoneal masses with SSWE are warranted. (Endokrynol Pol 2014; 65 (2): 119–124)Wstęp: Celem badania była ocena wykonalności i przydatności naddźwiękowej elastografii fali poprzecznej (SSWE) w diagnostyce łagodnych zmian ogniskowych nadnerczy.Materiał i metody: U 13 pacjentów wykonano badania ultrasonograficzne, oceniając 16 zmian ogniskowych nadnerczy z oceną ich spoistości z wykorzystaniem naddźwiękowej elastografii fali poprzecznej. Ostateczne rozpoznanie ustalono na podstawie wyników badań CT i MR, badań biochemicznych, operacji lub monitorowania ponad rok.Wyniki: Ostateczne rozpoznania: 6 zmian o typie guzkowego rozrostu kory nadnercza, 6 gruczolaków, 3 torbiele, 1 myelolipoma. Sygnał elastograficzny zarejestrowano we wszystkich litych guzach nadnerczy w przeciwieństwie do zmian torbielowatych, które nie wykazywały sygnału elastograficznego, zgodnie z zasadą, że fale poprzeczne nie rozchodzą się w płynach.Wnioski: Badanie z użyciem SSWE jest możliwe do wykonania i może być zastosowane w trakcie badań ultrasonograficznych jamy brzusznej i przestrzeni zaotrzewnowej. Metoda ta wykazała potencjał dla różnicowania litych i torbielowatych zmian ogniskowych nadnerczy. Uzasadnione są dalsze szerokie badania oceniające możliwość różnicowania guzów nadnerczy i innych zmian ogniskowych przestrzeni zaotrzewnowej. (Endokrynol Pol 2014; 65 (2): 119–124

    Ocena czterech wariantów klasyfikacji TIRADS w grupie pacjentów z wolem guzkowym — badanie wstępne

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    Purpose The goal this study was to evaluate the utility of four variants of the Thyroid Imaging Reporting and Data System (TIRADS) in the differentiation of focal lesions in individuals with multinodular goiter.   Materials and Methods The study was approved by the Local Bioethical Committee. Each patient gave informed consent before enrolment. A total of 163 nodules in 124 patients with multinodular goiter were evaluated by ultrasound. B-mode and PD imaging and strain elastography were performed. Archived images were evaluated via retrospective analysis using four different proposed TIRADS classifications   Results Sensitivity and specificity of the Horvath, Park, Kwak, and Russ classifications were 0.625 and 0.769, 0.813 and 0.864, 0.938 and 0.667, and 0.875 and 0.293, respectively. Positive and negative predictive values were 0.227 and 0.95, 0.394 and 0.977, 0.234 and 0.99, and 0.119 and 0.956, respectively. Receive operating characteristic analysis suggests that the best differentiation potential was demonstrated by the Kwak classification with an area under the curve (AUC) of 0.896, followed by the Park (AUC = 0.872), Horvath (AUC = 0.774), and Russ (AUC = 0.729) classifications.   Conclusion The TIRADS classification proposed by Kwak can be a useful tool in daily practice for the evaluation of thyroid cancer in individuals with multinodular goiter, particularly for selecting cases that require biopsy, which may improve and simplify clinical decision making. To adopt a definitive, comprehensive variant of the TIRADS classification with potential for universal, practical application, further prospective studies that include improvement of the lexicon and evaluation of the full spectrum of thyroid malignancy are warranted.Wstęp: Celem tej pracy była ocena przydatności 4 wariantów systemu raportowania badań ultrasonograficznych tarczycy (TIRADS) do różnicowania zmian ogniskowych u pacjentów z wolem guzkowym. Materiał i metody: Badanie było zatwierdzone przez właściwą komisję bioetyczną. Każdy pacjent wyraził świadomą zgodę przed przy­stąpieniem do badania. W badaniu ultrasononograficznym analizowano 163 zmiany ogniskowe u 124 pacjentów z wolem guzowatym. Wykonano obrazowanie w skali szarości, z dopplerem mocy oraz elastografię odkształceń względnych. Zarchiwizowane obrazy zostały poddane analizie retrospektywnej z zastosowaniem 4 wariantów klasyfikacji TIRADS. Wyniki: Czułość i swoistość klasyfikacji Horvath, Park, Kwak i Russ wyniosły odpowiednio 0,625 i 0,769, 0,813 i 0,864, 0,938 i 0,667 oraz 0,875 i 0,293. Dodatnie i ujemne wartości predykcyjne wynosiły odpowiednio 0,227 i 0,95, 0,394 i 0,977, 0,234 i 0,99 oraz 0,119 i 0,956. Analiza ROC sugeruje, że najlepszy potencjał w różnicowaniu prezentuje wariant Kwak z polem pod krzywą (AUC) of 0,896, następnie Park (AUC = 0,872), Horvath (AUC = 0,774) i Russ (AUC = 0,729). Wnioski: Klasyfikacja TIRADS proponowana przez Kwaka może być przydatnym narzędziem w codziennej praktyce oceny pod kątem raka tarczycy u pacjentów z wolem guzkowym, szczególnie do wyselekcjonowania przypadków wymagających biopsji, co może polepszyć i uprościć podjęcie decyzji klinicznej. Wskazane są dalsze badania prospektywne, obejmujące ulepszenie leksykonu i ocenę pełnego spektrum guzów złośliwych tarczycy, aby ostatecznie przyjąć optymalny wariant klasyfikacji TIRADS, co zapewne umożliwi jej uniwersalne praktyczne zastosowanie

    Effects of technetium on marine micro-organisms

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    Eleven bacterial species have been isolated from the upper layer of intertidal sediments collected along the Belgian coast (Coxyde). Three of them (no. 1, 4 and 11) have been chosen for their halophilous character. One species has been identified as Flavobacterium halmephilum, the other two are being investigated. Effects of technetium (99Tc) have been studied on a mixed bacterial population isolated from sediments, as well as on the three halophilic species.At the concentrations utilized in this work (up to 100 microg ml-1), 99Tc has no evident effects on bacterial growth. Uptake of technetium (99Tc and/or 95mTc) has been investigated in the mixed bacterial population, in the three halophilic bacteria (including Flavobacterium halmephilum) and in the benthic ciliate Uronema marinum. It has been found that technetium is taken up by all these micro-organisms. However, the transfer factor (TF) in bacteria may vary considerably (from 0.5 to 200), but the cause of this variability is not known and deserves further study.The ciliate Uronema marinum, which feeds on living marine bacteria, was found to take up 95mTc added to the culture medium. However, the TF in this ciliate is rather low (from 1.4 to 5.5). Because it feeds on bacteria, Uronema marinum is supposed to take up technetium from water (direct contamination) as well as from contaminated bacteria (indirect contamination). Experiments with 95mTc-labeled bacterial cells might be useful, as they could indicate which form of contamination (direct or indirect) is prevailing

    Shear Wave Elastography May Add a New Dimension to Ultrasound Evaluation of Thyroid Nodules: Case Series with Comparative Evaluation

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    Although elastography can enhance the differential diagnosis of thyroid nodules, its diagnostic performance is not ideal at present. Further improvements in the technique and creation of robust diagnostic criteria are necessary. The purpose of this study was to compare the usefulness of strain elastography and a new generation of elasticity imaging called supersonic shear wave elastography (SSWE) in differential evaluation of thyroid nodules. Six thyroid nodules in 4 patients were studied. SSWE yielded 1 true-positive and 5 true-negative results. Strain elastography yielded 5 false-positive results and 1 false-negative result. A novel finding appreciated with SSWE, were punctate foci of increased stiffness corresponding to microcalcifications in 4 nodules, some not visible on B-mode ultrasound, as opposed to soft, colloid-inspissated areas visible on B-mode ultrasound in 2 nodules. This preliminary paper indicates that SSWE may outperform strain elastography in differentiation of thyroid nodules with regard to their stiffness. SSWE showed the possibility of differentiation of high echogenic foci into microcalcifications and inspissated colloid, adding a new dimension to thyroid elastography. Further multicenter large-scale studies of thyroid nodules evaluating different elastographic methods are warranted

    Cation exchange HPLC analysis of desmosines in elastin hydrolysates

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    Desmosine crosslinks are responsible for the elastic properties of connective tissues in lungs and cardiovascular system and are often compromised in disease states. We developed a new, fast, and simple cation exchange HPLC assay for the analysis of desmosine and isodesmosine in animal elastin. The method was validated by determining linearity, accuracy, precision, and desmosines stability and was applied to measure levels of desmosines in porcine and murine organs. The detection and quantification limits were 2 and 4 pmol, respectively. The run-time was 8 min. Our cation exchange column does not separate desmosine and isodesmosine, but their level can be quantified from absorbance at different wavelengths. Using this assay, we found that desmosines levels were significantly lower in elastin isolated from various organs of immunodeficient severe combined immunodeficiency mice compared with wild-type animals. We also found that desmosines levels were lower in lung elastin isolated from hyperhomocysteinemic Pcft−/− mice deficient in intestinal folate transport compared with wild-type Pcft+/+ animals

    Study of ultrathin Pt/Co/Pt trilayers modified by nanosecond XUV pulses from laser-driven plasma source

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    We have studied the structural mechanisms responsible for the magnetic reorientation between in-plane and out-of-plane magnetization in the (25 nm Pt)/(3 and 10 nm Co)/(3 nm Pt) trilayer systems irradiated with nanosecond XUV pulses generated with laser-driven gas-puff target plasma source of a narrow continuous spectrum peaked at wavelength of 11 nm. The thickness of individual layers, their density, chemical composition and irradiation-induced lateral strain were deduced from symmetric and asymmetric X-ray diffraction (XRD) patterns, grazing-incidence X-ray reflectometry (GIXR), grazing incidence X-ray fluorescence (GIXRF), extended X-ray absorption fine structure (EXAFS) and transmission electron microscopy (TEM) measurements. In the as grown samples we found, that the Pt buffer layers are relaxed and that the layer interfaces are sharp. As a result of a quasi-uniform irradiation of the samples, the XRD, EXAFS, GIXR and GIXRF data reveal the formation of two distinct layers composed of Pt1-xCox alloys with different Co concentrations, dependent on the thickness of the as grown magnetic Co film but with similar ∼1% lateral tensile residual strain. For smaller exposure dose (lower number of accumulated pulses) only partial interdiffusion at the interfaces takes place with the formation of a tri-layer composed of Co-Pt alloy sandwiched between thinned Pt layers, as revealed by TEM. The structural modifications are accompanied by magnetization changes, evidenced by means of magneto-optical microscopy. The difference in magnetic properties of the irradiated samples can be related to their modification in Pt1-xCox alloy composition, as the other parameters (lateral strain and alloy thickness) remain almost unchanged. The out-of-plane magnetization observed for the sample with initially 3 nm Co layer can be due to a significant reduction of demagnetization factor resulting from a lower Co concentration
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