122 research outputs found

    Electrical conductivity in new imidazolium salts of dicarboxylic acids

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    Electrical conductivities of powder samples of five new imidazolium salts of aliphatic dicarboxylic acids (imidazolium malonate (1), imidazolium glutarate (2), imidazolium adipate monohydrate (3), diimidazolium suberate (4), imidazolium sebacate (5) were measured by impedance spectroscopy as a function of temperature. It was found that conductivities increase with temperature. At high temperatures, the lowest conductivity was determined for imidazolium glutarate (10 -5 S/m) and the highest -for imidazolium sebacate (10 -1 S/m). The correlation between crystal structures of the investigated salts and their ionic conductivities is discussed

    Thrombin inhibitory activity of some polyphenolic compounds

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    Thrombin, also known as an active plasma coagulation factor II, belongs to the family of serine proteases and plays a crucial role in blood coagulation process. The process of thrombin generation is the central event of the hemostatic process and regulates blood coagulant activity. For this reason, thrombin inhibition is key to successful novel antithrombotic pharmacotherapy. The aim of our present study was to examine the effects of the well-known polyphenolic compounds on the activity of thrombin, by characterization of its interaction with selected polyphenols using different biochemical methods and biosensor BIAcore analyses. Only six compounds, cyanidin, quercetin, silybin, cyanin, (+)-catechin and (−)-epicatechin, of all examined in this study polyphenols caused the inhibition of thrombin amidolytic activity. But only three of the six compounds (cyanidin, quercetin and silybin) changed thrombin proteolytic activity. BIAcore analyses demonstrated that cyanidin and quercetin caused a strong response in the interaction with immobilized thrombin, while cyanin and (−)-epicatechin induced a low response. Lineweaver–Burk curves show that used polyphenol aglycones act as competitive thrombin inhibitors. Our results suggest that polyphenolic compounds might be potential structural bases and source to find and project nature-based, safe, orally bioavailable direct thrombin inhibitors.This work was supported by Grant 545/485 and Grant 506/810 from the University of Lodz

    Constitutive modelling of skin ageing

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    The objective of this chapter is to review the main biomechanical and structural aspects associated with both intrinsic and extrinsic skin ageing, and to present potential research avenues to account for these effects in mathematical and computational models of the skin. This will be illustrated through recent work of the authors which provides a basis to those interested in developing mechanistic constitutive models capturing the mechanobiology of skin across the life course

    Rare variants in BNC2 are implicated in autosomal-dominant congenital lower urinary-tract obstruction

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    Congenital lower urinary-tract obstruction (LUTO) is caused by anatomical blockage of the bladder outflow tract or by functional impairment of urinary voiding. About three out of 10,000 pregnancies are affected. Although several monogenic causes of functional obstruction have been defined, it is unknown whether congenital LUTO caused by anatomical blockage has a monogenic cause. Exome sequencing in a family with four affected individuals with anatomical blockage of the urethra identified a rare nonsense variant (c.2557C>T [p.Arg853(∗)]) in BNC2, encoding basonuclin 2, tracking with LUTO over three generations. Re-sequencing BNC2 in 697 individuals with LUTO revealed three further independent missense variants in three unrelated families. In human and mouse embryogenesis, basonuclin 2 was detected in lower urinary-tract rudiments. In zebrafish embryos, bnc2 was expressed in the pronephric duct and cloaca, analogs of the mammalian lower urinary tract. Experimental knockdown of Bnc2 in zebrafish caused pronephric-outlet obstruction and cloacal dilatation, phenocopying human congenital LUTO. Collectively, these results support the conclusion that variants in BNC2 are strongly implicated in LUTO etiology as a result of anatomical blockage

    Profiling and imaging of forensic evidence – a pan-European forensic round robin study part 1: document forgery

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    The forensic scenario, on which the round robin study was based, simulated a suspected intentional manipulation of a real estate rental agreement consisting of a total of three pages. The aims of this study were to (i) establish the amount and reliability of information extractable from a single type of evidence and to (ii) provide suggestions on the most suitable combination of compatible techniques for a multi-modal imaging approach to forgery detection. To address these aims, seventeen laboratories from sixteen countries were invited to answer the following tasks questions: (i) which printing technique was used? (ii) were the three pages printed with the same printer? (iii) were the three pages made from the same paper? (iv) were the three pages originally stapled? (v) were the headings and signatures written with the same ink? and (vi) were headings and signatures of the same age on all pages? The methods used were classified into the following categories: Optical spectroscopy, including multispectral imaging, smartphone mapping, UV-luminescence and LIBS; Infrared spectroscopy, including Raman and FTIR (micro-)spectroscopy; X-ray spectroscopy, including SEM-EDX, PIXE and XPS; Mass spectrometry, including ICPMS, SIMS, MALDI and LDIMS; Electrostatic imaging, as well as non-imaging methods, such as non-multimodal visual inspection, (micro-)spectroscopy, physical testing and thin layer chromatography. The performance of the techniques was evaluated as the proportion of discriminated sample pairs to all possible sample pairs. For the undiscriminated sample pairs, a distinction was made between undecidability and false positive claims. It was found that none of the methods used were able to solve all tasks completely and/or correctly and that certain methods were a priori judged unsuitable by the laboratories for some tasks. Correct results were generally achieved for the discrimination of printer toners, whereas incorrect results in the discrimination of inks. For the discrimination of paper, solid state analytical methods proved to be superior to mass spectrometric methods. None of the participating laboratories deemed addressing ink age feasible. It was concluded that correct forensic statements can only be achieved by the complementary application of different methods and that the classical approach of round robin studies to send standardised subsamples to the participants is not feasible for a true multimodal approach if the techniques are not available at one location

    Ramipril and Risk of Hyperkalemia in Chronic Hemodialysis Patients

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    Angiotensin converting enzyme (ACE) inhibitors provide well known cardiorenal-protective benefits added to antihypertensive effects in chronic renal disease. These agents are underused in management of patients receiving hemodialysis (HD) because of common concern of hyperkalemia. However, few studies have investigated effect of renin angiotensin aldosterone system (RAAS) blockade on serum potassium in hemodialysis patients. We assessed the safety of ramipril in patients on maintenance HD. We enrolled 28 adult end stage renal disease (ESRD) patients treated by maintenance HD and prescribed them ramipril in doses of 1.25 to 5 mg per day. They underwent serum potassium concentration measurements before ramipril introduction and in 1 to 3 months afterwards. No significant increase in kalemia was found. Results of our study encourage the use of ACE inhibitors in chronically hemodialyzed patients, but close potassium monitoring is mandatory

    Summary of homogeneous combustion kinetic studies of lean methane-air mixtures in monolith bed

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    Przedstawiono wyniki badań kinetycznych niekatalitycznego spalania niskostężonych mieszanin metan-powietrze na monolitycznym wypełnieniu strukturalnym w szerokim zakresie temperatur, prowadzonych w ramach pracy doktorskiej [1]. W pracy wykazano, że mechanizm i kinetyka reakcji zależą nie tylko od wielkości i rodzaju powierzchni wypełnienia, z którą kontaktuje się faza gazowa w strefie spalania, ale również od temperatury w tej strefie. Sformułowano hipotezę dotyczącą zależności udziału heterogenicznego spalania powierzchniowego (na ściankach wypełnienia) i homogenicznego (w wolnej przestrzeni) w zależności od temperatury w strefie spalania. Opracowano stosowne równania kinetyczne.The paper presents results of kinetic studies of noncatalytic combustion of lean methane-air mixtures in monolith bed in a wide range of temperatures being carried out within PhD Thesis [1]. The study reveals an influence of size, type of monolith’s surface and temperature in combustion zone on the reaction mechanism and its kinetics. A hypothesis that the share of combustion type: heterogeneous with surface effect (on the monolith’s wall) and homogeneous (in the free space) depends on the temperature in the combustion zone was formulated. The appropriate kinetic equations were estimated
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