230 research outputs found

    Positron Trapping Effects in Water-filled Nanopores of Spinel Ceramics

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    The water-sensitive positron trapping modes in nanoporous MgAl2O4 ceramics with a spinel structure are studied. It is shown that water-sorption processes in these ceramics leads to increase in positron trapping rates of extended defects located near intergranual boundaries. The fixation of direct positron lifetime components allows refining the most significant changes in positron trapping rate. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3503

    Nature and spirit: Arne Korsmo and Frank Lloyd Wright's organicism

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    O arquitecto norueguês Arne Korsmo (1900-1968) é frequentemente associado aos princípios orgânicos defendidos pelo arquitecto americano Frank Lloyd Wright (1867-1959) em consonância com a sua obra no período pós-Segunda Guerra Mundial. O exemplo mais emblemático é Villa Planetveien 12 (1955) projetada por Korsmo e seus colaboradores, em Oslo. Antes da Segunda Guerra Mundial, Korsmo era conhecido como "Le Corbusier da Noruega". No entanto, ao compararmos o percurso de Wright, iniciado na infância, durante a construção de seus princípios orgânicos; com o percurso intelectual e arquitectónico percorrido por Korsmo, podemos identificar paralelos entre esses dois arquitetos. Korsmo teria se tornado orgânico em termos "Wrightianos" mesmo sem a influência direta de Wright? Korsmo já era orgânico antes da Segunda Guerra Mundial? Nossa tese é que o "Korsmo orgânico" existia antes da Villa Planetveien 12. Argumentamos que o caminho de Frank Lloyd Wright rumo ao seus princípios orgânicos abre uma porta para entendermos tanto o próprio organicismo de Korsmo quanto sua atração pelo Funcionalismo. Esta tese apresenta três pressupostos que interligam eventos cruciais na vida de Korsmo e Wright; fundamentada nas ideias transcendentais de uma das maiores referências de Frank Lloyd Wright, o filósofo, ensaísta e poeta norte-americano Ralph Waldo Emerson (1803-1882).The Norwegian architect Arne Korsmo (1900-1968) is often associated with the organic principles defended by the American architect Frank Lloyd Wright (1867-1959) in keeping with his work in the post-World War II (WWII) period. The most emblematic example comes with Villa Planetveien 12 (1955) designed by Korsmo and his collaborators, in Oslo. Prior to WWII, Korsmo had been known as "Norway's Le Corbusier." Nevertheless, by comparing Wright's journey towards the construction of his organic principles from an early age with Korsmo's own path, we are able to identify further parallels between these two architects. Would Korsmo have become organic in "Wrightian" terms even without the direct influence of Wright? Was Korsmo already organic prior to WWII? Our thesis is that the organic Korsmo existed prior to Villa Planetveien 12. We also argue that Frank Lloyd Wright's path towards his organic principles opens a door to understanding both Korsmo's own organicism and his attraction to Functionalism. This thesis presents three assumptions that interconnect crucial events in Korsmo and Wright's life; grounded by the transcendental ideas of one of Frank Lloyd Wright's major reference, the American philosopher, essayist and poet Ralph Waldo Emerson (1803-1882)

    Reduction of defibrillation threshold and safety of usage of a new model of subcutaneous defibrillation lead

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    This study was designed to evaluate the performance of a new single coil model of a subcutaneous defibrillation lead (Medtronic, 6996S) by assessing its capability to lower the defibrillation threshold. The 6996S lead is a permanent unipolar subcutaneous lead with a short (15 cm) defibrillation coil. Additionally, the safety of the lead and its chronic stability were evaluated. The investigation was performed in patients who underwent implantation of an ICD system consisting of a single coil RV lead with a left sub-clavicular Active Can ICD. In these patients, the DFT was determined twice during the implantation procedure with a binary search protocol, once with an ICD system which included the 6996S lead (RV → Can + SQ), and once without the 6996S lead (RV → Can). The order in which the implanted system configurations were tested was randomised. Between June 2004 and February 2006, 32 patients were enrolled into the study. Post-implantation follow-up was of at least three-month duration. The DFT test results of 31 patients have been analysed. The average DFT of (Can → RV) and (Can + 6996S → RV) were respectively 14.3 ± 9.9 J and 10.5 ± 6.2 J (p = 0.007). The addition of the 6996S lead with 15 cm coil reduced the average DFT by 27%, which is about 80% of the DFT reduction obtained with the 6996 lead with 25 cm coil. Adverse events, predominantly related to progression of heart failure, were observed in eight (26%) patients during the study and were related neither to the particular 6996S lead model, nor to the implant procedure. The short-coil (6996S) SQ lead significantly reduced mean DFT. The implant procedure is safe, but the 6996S lead requires / warrants long-term surveillance / observation due to retraction of the tip of the lead, ranging from 1 to 4 cm, found in eight of 14 patients (57%) implanted with this lead model

    Profiling the Proteome of Cyst Nematode-Induced Syncytia on Tomato Roots

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    Cyst nematodes are important herbivorous pests in agriculture that obtain nutrients through specialized root structures termed syncytia. Syncytium initiation, development, and functioning are a research focus because syncytia are the primary interface for molecular interactions between the host plant and parasite. The small size and complex development (over approximately two weeks) of syncytia hinder precise analyses, therefore most studies have analyzed the transcriptome of infested whole-root systems or syncytia-containing root segments. Here, we describe an effective procedure to microdissect syncytia induced by Globodera rostochiensis from tomato roots and to analyze the syncytial proteome using mass spectrometry. As little as 15 mm2 of 10-µm-thick sections dissected from 30 syncytia enabled the identification of 100–200 proteins in each sample, indicating that mass-spectrometric methods currently in use achieved acceptable sensitivity for proteome profiling of microscopic samples of plant tissues (approximately 100 µg). Among the identified proteins, 48 were specifically detected in syncytia and 7 in uninfected roots. The occurrence of approximately 50% of these proteins in syncytia was not correlated with transcript abundance estimated by quantitative reverse-transcription PCR analysis. The functional categories of these proteins confirmed that protein turnover, stress responses, and intracellular trafficking are important components of the proteome dynamics of developing syncytia

    Ranolazyna — nowy lek w nawracających opornych na leczenie arytmiach komorowych?

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    Introduction. The pharmacological treatment of ventricular arrhythmias (VA) has significant limitations. Ranolazine is a relatively new drug with documented antianginal and anti-ischaemic mechanisms and where preclinical data provides evidence of additional antiarrhythmic properties.  The aim of this article was to evaluate the safety and efficacy of ranolazine in patients with recurrent antiarrhythmic therapy-refractory VA.  Material and methods. This prospective evaluation included 30 patients (pts) (male/female: 26/4; mean age: 65 ± 10 years; coronary artery disease/dilated cardiomyopathy: 20/10; New York Heart Association class I/II/III/IV: 2/14/12/2, left ventricular ejection fraction: 27 ± 10%; implantable cardioverter-defibrillator (ICD): 15 pts, implantable cardioverter- -defibrillator with cardiac resynchronisation therapy (CRT-D): 14 pts with recurrent significant VA [ventricular fibrillation, sustained ventricular tachycardia (VT) and/or non-sustained VT, multiple ventricular premature complexes > 1,000/ /day, biventricular stimulation (BiV) < 95%] and where standard treatment options, i.e. pharmacotherapy, coronary revascularisation, and percutaneous ablation, had proved ineffective. The severity of the arrhythmia was assessed by 24-hour electrocardiographic (ECG) Holter monitoring and in ICD/CRT-D memory recording. The patients received, in addition to the standard pharmacotherapy (amiodarone: 18 pts, beta-blocker: 26 pts) ranolazine 375 mg twice daily for three months. Baseline data was compared to the data obtained after the three months of ranolazine treatment.  Results. We observed a significant reduction of total ventricular extrasystoles determined by ECG Holter monitoring (median: 1,737 vs 1,260, p = 0.04). Similarly, significant VA in ICD/CRT-D memory recording was diminished (67.7 vs 35.5%, p = 0.03). The number of ICD interventions in terms of both antitachycardia pacing (9 pts vs 2 pts, p = 0.01), and shock delivery (8 pts vs 2 pts, p = 0.01), was lower after the three-month observation. The therapy was ineffective for nine (29%) patients — two were hospitalised during the three-month follow-up because of recurrent arrhythmia and in seven pts there was no noticeable reduction in the amount of VA. Adverse effects, in the form of gastrointestinal symptoms (diarrhoea: two, constipation: one), occurred in three (10%) patients.  Conclusions. Authors observed no significant QT prolongation in any patient. There were no differences between the baseline and the post-ranolazine patient clinical characteristics. Ranolazine seems to be a safe and effective second- line therapy in the reduction of VA and ICD interventions in patients with recurrent antiarrhythmic therapy-refractory events.   Wstęp. Farmakologiczne leczenie komorowych zaburzeń rytmu (VA) jest ograniczone. Ranolazyna to stosunkowo nowy lek o udokumentowanym działaniu przeciwdławicowym i przeciwniedokrwiennym oraz z danymi przedklinicznymi wska- zującymi na dodatkowe właściwości antyarytmiczne.  Celem pracy była ocena bezpieczeństwa i skuteczności ranolazyny u pacjentów z nawracającymi opornymi na leczenie VA.  Materiał i metody. Prospektywną oceną objęto 30 pacjentów (pts) (mężczyźni/kobiety: 26/4, średnia wieku: 65 ± 10 lat; choroba wieńcowa/kardiomiopatia rozstrzeniowa: 20/10, klasa I/II/III/IV według New York Heart Association: 2/14/12/2, frakcja wyrzutowa lewej komory: 27 ± 10%; kardiowerter-defibrylator [ICD]: 15 pts, terapia resynchronizują- ca serce z funkcją defibrylacji [CRT-D]: 14 pts) z nawracającymi istotnymi VA (migotanie komór, utrwalony częstoskurcz komorowy [VT] i/lub nieutrwalony VT, liczne pojedyncze ekstrasystolie komorowe &gt; 1000/d., stymulacja biwentrikularna (BiV) &lt; 95%) i z wyczerpaną standardową opcją leczenia, tj. farmakoterapią, rewaskularyzacją wieńcową i przezskórną ablacją. Nasilenie arytmii oceniano w 24-godzinnym monitorowaniu elektrokardiograficznym (EKG) metodą Holtera oraz w pamięci holterowskiej ICD/CRT-D. U pacjentów do standardowej farmakoterapii (amiodaron: 18 pts, beta-adrenolityk: 26 pts) dołączono ranolazynę w dawce 375 mg 2 razy/dobę przez 3 miesiące. Wyjściowe dane porównano z danymi uzyskanymi po 3-miesięcznym leczeniu.  Wyniki. Autorzy zaobserwowali istotną redukcję liczby ekstrasystolii komorowych w monitorowaniu EKG metodą Holtera (mediana: 1737 v. 1260; p = 0,04). Podobnie odnotowano istotne zmniejszenie częstości istotnej VA w zapisie pamięci ICD/CRT-D (67,7 v. 35,5%; p = 0,03). Liczba interwencji ICD zarówno pod względem stymulacji antyarytmicznej (9 pts v. 2 pts; p = 0,01), jak i wyładowań (8 pts v. 2 pts; p = 0,01) była niższa po 3-miesięcznej obserwacji. Terapia była nieskuteczna u 9 (29%) pacjentów — 2 hospitalizowano w trakcie 3-miesięcznej obserwacji z powodu nawrotu VA, a u 7 nie stwierdzono zauważalnego zmniejszenia występowania VA. Działania niepożądane pod postacią dolegliwości żołądkowo-jelitowych (biegunka: 2, zaparcie: 1) wystąpiło u 3 (10%) chorych. U żadnego z pacjentów nie obserwowano istotnego wydłużenia odstępu QT. Nie obserwowano istotnych różnic w charakterystyce klinicznej pacjentów wyjściowo i po podaniu ranolazyny.  Wnioski. Ranolazyna wydaje się bezpiecznym i skutecznym lekiem drugiego rzutu, który może być stosowany w redukcji VA i liczby interwencji ICD u pacjentów z nawracającymi opornymi na leczenie VA.

    Free-volume correlations in positron-sensitive annihilation modes in chalcogenide vitreous semiconductors: on the path from illusions towards realistic physical description

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    A newly modified correlation equation between defect-related positron lifetime t₂ (ns) defined within two-state model and corresponding radius R (Å) of freevolume positron traps in the full non-linear form or simplified linear-approximated is proved to account for compositional trends in void volume evolution of chalcogenide semiconductor compounds like binary As-S(Se) glasses. Specific chemical environment of free-volume voids associated with neighbouring network-forming polyhedrons is shown to play a decisive role in this correlation, leading to systematically enhanced estimated void sizes in comparison with typical molecular substrates, such as polymers

    NT-proBNP level in the diagnosis of isolated left ventricular diastolic dysfunction in patients with documented coronary artery disease

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    Background: The diagnostic value of NT-proBNP for left ventricular (LV) systolic dysfunction is well established. However, its role for diastolic dysfunction (DD) diagnosis in patients with preserved systolic function has not been clearly defined. Methods: A total of 83 patients with documented coronary arterial disease following anterior myocardial infarction and with a left ventricular ejection fraction (LVEF) > 45% were enrolled. According to echocardiographic mitral inflow and right upper pulmonary vein flow, DD was excluded in 32 patients (group A). The patients with DD were divided into three subgroups: B1 - 38 patients with impaired relaxation, B2 - 8 patients with pseudonormalisation and B3 - 7 patients with restrictive inflow. In all patients E-wave propagation (Vp) and NT-proBNP were determined. Results: Mean LVEF was 56.2 &plusmn; 9% and did not differ between the subgroups. NT-proBNP levels were 107 &plusmn; 101 pg/ml in group A, 299 &plusmn; 281 pg/ml in B1, 734 &plusmn; 586 pg/ml in B2 (p < 0.05 vs. A) and 2322 &plusmn; 886 pg/ml in B3 (p < 0.01 vs. A and p < 0.01 vs. B2). Propagation Vp was 69 &plusmn; 21 cm/s, 56 &plusmn; 20 cm/s, 53 &plusmn; 17 cm/s (p < 0.05 vs. A) and 44 &plusmn; 11 cm/s (p < 0.01 vs. A) respectively. A positive correlation was found for DD degree with NT-proBNP level (r = 0.66; p < 0.001) and negative with Vp (r = &#8211;0.41; p < 0.001). ROC curves were constructed to determine the NT-proBNP level cut-off point for DD (> 131 pg/ml, area under the curve: 0.63) and advanced restrictive DD (> 1670 pg/ml, area under the curve: 0.83) diagnosis. Sensitivity, specificity, accuracy and positive and negative predictive values were 71%, 50%, 63%, 69%, 52% and 57%, 99%, 95%, 80%, 96% respectively. Conclusions: In patients with coronary artery disease and preserved LV systolic function a single NT-proBNP measurement helps to identify those with isolated DD, especially those with advanced restriction

    The prognostic value of contrast echocardiography, electrocardiographic and angiographic perfusion indices for prediction of left ventricular function recovery in patients with acute myocardial infarction treated by percutaneous coronary intervention

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    Background: Fast and effective culprit artery patency restoration is important in acute myocardial infarction (MI) but does not ensure that tissue perfusion related to a better prognosis in the long-term follow-up is achieved. In this study we compared the prognostic value of myocardial perfusion contrast echocardiography with other well-known electrocardiographic and angiographic indices of preserved tissue perfusion. Material and methods: We studied 114 consecutive patients, of whom 85 were male, aged 57.9 &#177; 11 years, within 12 hours of the onset of symptoms of their first anterior myocardial infarction. These were treated with primary PCI, after which PCI myocardial blush grading was assessed (MBG 0-1 no perfusion, 2-3 normal perfusion). One hour after PCI a reduction of > 50% in the sum of ST-segment elevation (&#931;ST 50%) was assessed as an indicator of perfusion restoration. During the first 24 hours continuous ECG monitoring recorded reperfusion arrhythmias (RA) and the time required for ST-segment reduction to exceed 50% in the single lead with the highest ST elevation (&#916;t ST 50%). On the next day of MI, after LVEF evaluation, real-time myocardial contrast echocardiography (RT-MCE) was performed to assess perfusion in dysfunctional segments. The reperfusion index as an average of the dysfunctional segment perfusion score was determined. Regional and global LV function was assessed again one month after MI. An LVEF increase of over 5% divided the patients into two groups: group A with LVEF improvement (72 pts) and group B without LVEF improvement (42 pts). Results: In group A baseline LVEF was 41.9 &#177; 7.1% and in group B it was 38.9 &#177; 7.4% (p = NS). The reperfusion indices were 1.59 and 0.78 (p < 0.001) respectively. MBG 2-3 occurred more often in group A (64%) than in group B (34%) p < 0.001. &#931; ST50% and &#916;t ST 50%, after determination of the cut point on the ROC curve (61 min), occurred in 47 and 48 patients in group A and 17 and 16 patients in group B respectively. The accuracy of the tests under discussion for LVEF prognosis was 76.3%, 64%, 63.2% and 64.9% for RT-MCE, MBG, SST50% and &#916;t ST 50% respectively. Conclusions: Myocardial perfusion echocardiography had a high prognostic value for the prediction of LV global function improvement. It turned out to be the best predictor among the other angiographic, echocardiographic and electrocardiographic markers

    Analiza odstępu QT u pacjentów z jadłowstrętem psychicznym

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    Objective: Patients with anorexia nervosa (AN) are at increased risk of ventricular arrhythmias, which are considered to be associated with QT interval prolongation. The aims of this study was to analyse the QT interval in patients with AN considering the potential impact of pharmacotherapy and to verify various QT correction formulas. Method: Fifty-six patients hospitalized with AN (average age: 22.8±5.6 years; F/M: 54/2, mean BMI=13.6±2.6 kg/m2) were enrolled to analysis: Group non-D (n=44; 78,6%) included patients, who did not use drugs that prolong the QT interval, group D (n=12; 21,4%) included patients, who were treated with such drugs. QT intervals were measured in a 12-lead ECG and corrected using the four formulas: Bazett, Fridericia, Framingham and Hodges. Results: Mean heart rate (HR) was similar in both groups (61±16.3 bpm in group D vs 63.1±18.7 bpm in non-D, p &gt; 0.05). Pathological bradycardia (HR &lt; 50 bpm) was present in 5 patients (41.7%) in group D and in 13 patients (29.5%) in group non-D. QTc interval corrected with Framingham formula was longer in Group-D (459±81ms) vs non D-group (413±33ms) p=0.04. QT interval corrected with Bazett and Hodges formulas was significantly dependent on HR (R= -0.29, p=0.03 and R= -0.42, p=0.001, respectively). Influence of HR on results of Fridericia and Framingham formulas was not significant (R = -0.22, p=0.1 and R = -0.11, p=0.4). Conclussions: Information about pharmacotherapy in AN patients is key for QTc assessment. Choice of correction formula has impact on the QTc. QTc obtained using Framingham and Fridericia formulas were the least dependent on heart rate.Cel: pacjenci z jadłowstrętem psychicznym (AN) są narażeni na zwiększone ryzyko komorowych zaburzeń rytmu, które są związane z wydłużeniem odstępu QT. Celem pracy była analiza odstępu QT u pacjentów z AN z uwzględnieniem potencjalnego wpływu farmakoterapii oraz weryfikacja różnych formuł korekcji QT. Metoda: Do analizy włączono 56 pacjentów hospitalizowanych z powodu AN (średni wiek: 22,8 ± 5,6 lat; K / M: 54/2, średni BMI = 13,6 ± 2,6 kg / m2): grupę non-D (n = 44; 78,6%) stanowili chorzy niestosujący leków wydłużających odstęp QT, grupa D (n = 12; 21,4%) to chorzy, którzy byli leczeni takimi lekami. Odstępy QT mierzono w 12-odprowadzeniowym EKG i korygowano przy użyciu czterech wzorów: Bazett, Fridericia, Framingham i Hodges. Wyniki: Średnia częstość akcji serca (HR) była podobna w obu grupach (61 ± 16,3 bpm w grupie D vs 63,1 ± 18,7 bpm w non-D, p> 0,05). Bradykardia (H
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