Studium mechanickych vlastnosti uhlikovych kompozitu.

Available from STL, Prague, CZ / NTK - National Technical LibrarySIGLECZCzech Republi

Studium mechanickych vlastnosti uhlikovych kompozitu.

Carbon-carbon composites made in the USMH in Prague and testing their mechanical properties are the subjects of the dissertation work. The original purpose was to use these composites for medical objects as replacements of fixing bones directly in human tissues. In the theoretical section there are described the production and properties of carbon fibres, textile reinforcements from carbon fibres, production and properties of C - C and C -P composites and their practice use. In the experimental section there are described the concrete samples of C - C and C - P composites, their production and the results of their testing. These composites are compared from the view of their mechanical properties resulting from the measurings and from the view of propriety of the used textile reinforcements. The measuring values of mechanical properties of a C - C composite are very low in comparison with the measuring values of tested C - P composites and of foreign C - C composites. In the discussion the measuring values are compared with the values calculated from the theory of composites and a hypothesis about degradation of carbon fibres caused by high manufacturing temperatures during the production of C - C composites is pronounced.Available from STL Prague, CZ / NTK - National Technical LibrarySIGLECZCzech Republi

Lab exercises for a discrete structures course: exploring logic and relational algebra with Alloy

Students in computing disciplines need a strong basis in the fundamentals of discrete mathematics, but traditional offline approaches to teaching this material provide limited opportunities for the kind of interactive learning that computing students experience in their programming assignments. We have been using the Alloy language and analyzer to teach concepts in discrete structures (relational algebra, logic, and graphs) in an exploratory, programming-oriented way. Alloy, however, constitutes a new programming paradigm for introductory students, and careful mediation is needed to keep students on track. We use the familiar programming lab format, where students work on small-scope problems co-located with instructors, to provide guidance as students wrestle with the languages of relational algebra and predicate logic through Alloy. We describe selected lab exercises, and report on initial findings based on our experiences with students

Specifická magnetická izolace E6 HPV16 upravených magnetizovatelných částic spolu s PCR a elektrochemickou detekcí

The majority of carcinomas that were developed due to the infection with human papillomavirus (HPV) are caused by high-risk HPV types, HPV16 and HPV18. These HPV types contain the E6 and E7 oncogenes, so the fast detection of these oncogenes is an important point to avoid the development of cancer. Many different HPV tests are available to detect the presence of HPV in biological samples. The aim of this study was to design a fast and low cost method for HPV identification employing magnetic isolation, polymerase chain reaction (PCR) and electrochemical detection. These assays were developed to detect the interactions between E6-HPV16 oncogene and magnetizable particles (MPs) using commercial Dynabeads M-280 Streptavidin particles and laboratory-synthesized “homemade” particles called MANs (MAN-37, MAN-127 and MAN-164). The yields of PCR amplification of E6-HPV16 oncogene bound on the particles and after the elution from the particles were compared. A highest yield of E6-HPV16 DNA isolation was obtained with both MPs particles commercial M-280 Streptavidin and MAN-37 due to reducing of the interferents compared with the standard PCR method. A biosensor employing the isolation of E6-HPV16 oncogene with MPs particles followed by its electrochemical detection can be a very effective technique for HPV identification, providing simple, sensitive and cost-effective analysis.Většina karcinomů, které byly vyvolané v důsledku infekce lidským papilomavirem (HPV), jsou způsobeny vysoce rizikovými typy HPV, HPV16 a HPV18. Tyto typy HPV obsahují E6 a E7 onkogeny, takže rychlá detekce těchto onkogenů je důležitý bod k zabránění rozvoje rakoviny. Mnoho různých HPV testů je k dispozici pro detekci přítomnosti HPV v biologických vzorcích. Cílem této studie bylo navrhnout rychlou a levnou metodu pro identifikaci HPV využívající magnetickou izolaci, polymerázovou řetězovou reakci (PCR) a elektrochemickou detekci. Tyto testy byly vyvinuty s cílem odhalit interakce mezi E6-HPV16 onkogenem a magnetizovatelnými částicemi (MPS) s použitím komerčních částic Dynabeads M-280 Streptavidin a laboratorně syntetizovaných "homemade" částic zvaných MAN (MAN-37, MAN-127 a MAN-164). Byly porovnány výnosy z PCR amplifikace onkogenu E6-HPV16 vázaného na částicích a po eluci z částic. Nejvyšším výnos z izolace E6-HPV16 DNA byl získán s oběma komerčními MPs částicemi M-280 Streptavidin a MAN-37 v důsledku snížení interferencí ve srovnání se standardní metodou PCR. Biosenzor používající izolaci E6-HPV16 onkogenu s MPs částicemi následovaný jeho elektrochemickou detekci může být velmi účinná technika pro identifikaci HPV, která umožňuje jednoduchou, citlivou a nákladově efektivní analýzu

Infectious Complications and Immune/Inflammatory Response in Cardiogenic Shock Patients: A Prospective Observational Study.

IntroductionPatients with cardiogenic shock (CS) are at a high risk of developing infectious complications; however, their early detection is difficult, mainly due to a frequently occurring noninfectious inflammatory response, which accompanies an extensive myocardial infarction (MI) or a postcardiac arrest syndrome. The goal of our prospective study was to describe infectious complications in CS and the immune/inflammatory response based on a serial measurement of several blood-based inflammatory biomarkers.MethodsEighty patients with CS were evaluated and their infections were monitored. Inflammatory markers (C-reactive protein, procalcitonin, pentraxin 3, presepsin) were measured seven times per week. The control groups consisted of 11 patients with ST segment elevation myocardial infarction without CS and without infection, and 22 patients in septic shock.ResultsInfection was diagnosed in 46.3% of patients with CS; 16 patients developed an infection within 48 h. Respiratory infection was most common, occurring in 33 out of 37 patients. Infection was a significant or even the main reason of death only in 3.8% of all patients with CS, and we did not find statistically significant difference in 3-month mortality between group of patients with CS with and without infection. There was no statistically significant prolongation of the duration of mechanical ventilation associated with infection. Strong inflammatory response is often in patients with CS due to MI, but we found no significant difference in the course of the inflammatory response expressed by evaluated biomarkers in patients with CS with and without infection. We found a strong relationship between the elevated inflammatory markers (sampled at 12 h) and the 3-month mortality: the area under the curve of receiver operating characteristic ranged between 0.683 and 0.875.ConclusionThe prevalence of infection in patients with CS was 46.3%, and respiratory tract infections were the most common type. Infections did not prolong statistically significantly the duration of mechanical ventilation and did not increase the prevalence of hospital mortality in this high-risk CS population. CS due to acute myocardial infarction was accompanied by a strong and highly variable inflammatory response, but it did not reach the intensity of the inflammatory response observed in patients with septic shock. An extensive immune/inflammatory response in patients with CS is linked to a poor prognosis

Delayed-Type Hypersensitivity to Metals of Environmental Burden in Patients with Takotsubo Syndrome – Is There a Clinical Relevance?

<div><p>Objective</p><p>Takotsubo syndrome (TS) is a heart condition characterised by a sudden transient left ventricular dysfunction; its pathophysiology is probably associated with elevated levels of catecholamines but the exact mechanism is not known as yet. Literature and clinical experience suggest that TS affects persons with various comorbidities. This pilot work aims to evaluate the frequency of comorbidities with potential pathological immune reactivity, and to evaluate the potential association between TS and hypersensitivity to metals assessed by LTT-MELISA®.</p><p>Methodology, Results</p><p>A total of 24 patients (23 women, 1 man) with a history of TS attack and 27 healthy controls were evaluated. Hypersensitivity was evaluated by a lymphocyte transformation test (LTT-MELISA®); a questionnaire of environmental burden was used to select evaluated metals. A total of 19 patients (79%) had at least one condition that might potentially be associated with pathological immune reactivity (autoimmune thyroid disease, drug allergy, bronchial asthma, cancer, contact dermatitis, rheumatoid arthritis). Hypersensitivity to metals was identified significantly more frequently in TS patients than in healthy controls (positive reaction to at least one metal was identified in 95.8% of TS patients and in 59.3% of controls; p = 0.003); the difference was statistically significant for mercury (45.8% and 14.8%, respectively; p = 0.029).</p><p>Conclusion</p><p>Our work shows that conditions with pathological immune reactivity occur frequently in TS patients, and our data suggest a possible association between TS and hypersensitivity to metals (mercury in particular) evaluated by LTT-MELISA®. We also suggest that apart from the triggering stress factor, potential existence of other serious conditions should be considered when taking medical history of TS patients.</p></div

Comparison of a number of patients with positive stimulation index (SI ≥ 3) for individual metals between TS group and healthy controls.

<p>Comparison of a number of patients with positive stimulation index (SI ≥ 3) for individual metals between TS group and healthy controls.</p

Basic characteristics of the TS group and the control group of healthy individuals.

<p>Basic characteristics of the TS group and the control group of healthy individuals.</p

Overview of environmental burden with metals in the TS group and in the control group.

<p>Overview of environmental burden with metals in the TS group and in the control group.</p

Suggested hypothesis of pathological immune mechanisms in the Takotsubo syndrome.

<p>TS is associated with increased levels of catecholamines in the acute phase of this condition. Hypersensitivity reactions to environmental burden with metals, which are mediated by antigen/hapten-specific T-lymphocytes, were proved in 96% of our patients with Takotsubo syndrome. Chronic or acute hypersensitivity reactions are accompanied by an inflammatory reaction with the production of many cytokines and free radicals (i.e., an increased oxidative stress). The methionin-homocysteine cycle is one of the main endogenous antioxidant systems. At the same time, the methionine-homocysteine cycle provides methyl groups for the degradation of catecholamines, a process catalysed by catechol-O-methyltransferase (COMT). An “exhaustion” of the methionine-homocysteine cycle as a result of chronic oxidative stress can lead to a decreased degradation of catecholamines; in a subsequent stressful situation, which is generally characterised by an increased production of catecholamines, excessively high levels of catecholamines can occur, such as those typically found in TS patients. TS develops most frequently in postmenopausal women, who have decreased levels of sex hormones, particularly oestrogens. In general, oestrogens have a cardioprotective effect (by reducing the chronotropic and ionotropic effects of catecholamines); additionally, when taking into account the potential hypersensitivity, oestrogens also have anti-inflammatory effects. On top of that, progesterone–of which levels also decrease with age–has immunosuppressive effects.</p