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Dzwonkowski M.,Gdask University of Technology | Dzwonkowski M.,Medical University of Gdask | Rykaczewski R.,Gdask University of Technology
Journal of Telecommunications and Information Technology

In this paper Quaternion Feistel Cipher (QFC) with an infinite key space based on quaternion Julia sets is proposed. The basic structure of the algorithm is based on the scheme proposed in 2012 by Sastry and Kumar. The pro-posed algorithm uses special properties of quaternions to per-form rotations of data sequences in 3D space for each of the cipher rounds. It also uses Julia sets to form an infi-nite key space. The plaintext is divided into two square ma-trices of equal size and written using Lipschitz quaternions. A modular arithmetic was implemented for operations with quaternions. A computer-based analysis has been carried out and obtained results are shown at the end of this paper. Source

Le Page A.,Universite de Sherbrooke | Bourgade K.,Universite de Sherbrooke | Lamoureux J.,Universite de Sherbrooke | Frost E.,Universite de Sherbrooke | And 5 more authors.
Journal of Alzheimer's Disease

Alzheimeŕs disease (AD) is a progressive irreversible neurological brain disorder characterized by accumulation of amyloid-β, amyloid plaques, and neurofibrillary tangles. Inflammation and immune alterations have been linked to AD, suggesting that the peripheral immune system plays a role during the asymptomatic period of AD. NK cells participate in innate immune surveillance against intracellular pathogens and malignancy but their role in AD remains controversial.We have investigated changes in peripheral NK cell phenotypes and functions in amnestic mild cognitive impairment (aMCI, n = 10), patients with mild AD (mAD, n = 11), and healthy elderly controls (n = 10). Patients selected according to NINCDS-ADRDA criteria were classified using neuropsychological assessment tests. Phenotype analysis revealed differences in expression of CD16 (increased in mAD), NKG2A (decreased in aMCI), and TLR2 and TLR9 (both decreased in mAD). Functional assays revealed that NK cell killing activity and degranulation (CD107 expression) were unchanged in the three groups. In contrast, expression of the CD95 receptor was increased in aMCI and mAD. Granzyme B expression and cytokine production (TNFa, IFN.) were increased in aMCI but not in mAD. CCL19- but not CCL21-dependent chemotaxis was decreased in aMCI and mAD, despite the fact that CCR7 expression was increased in aMCI. Our data suggest that the number of alterations observed in peripheral NK cells in aMCI represent an activation state compared to mAD patients and that may reflect an active immune response against a still to be defined aggression. © 2015 - IOS Press and the authors. All rights reserved. Source

Sawicki W.,Medical University of Gdask | Mazgalski J.,Medical University of Gdask | Mazgalski J.,Pharmaceutical Works Polpharma SA | Jakubowska I.,Medical University of Gdask
Drug Development and Industrial Pharmacy

Background: Coating, as a processing technique, applied to active pharmaceutical ingredient (API) crystals or particles (carriers) with an appropriate polymer allows to obtain a modified-release pharmaceutical dosage form. Such carriers can be the basic ingredient of a multi-unit dosage form. Additionally, coated API crystals (microcapsules) can provide an alternative to spherical granulate (pellets) as the main and most commonly used component of multi-unit dosage forms. Coating individual API crystals is a complicated process because of the crystals having insufficient size (below 100 μm), irregular shape, low mechanical durability and the fact that API crystals dissolve upon contact with the coating mixture, and other factors. Method: Compaction process was used to eliminate these inconveniences allowing us to obtain tramadol hydrochloride (TH) microcapsule cores in the size range of 212500 μm. The coating of the cores was successfully conducted using a fluidized-bed coating technique with four different polymers that allowed us to attain slow release of TH. Then, the microcapsules were subjected to a hot tabletting process conducted by applying a low compression force of about 1 kN at 56°C. Semi-liquid granules containing melted PEG 3000 combined with TH microcapsules were compressed. A tablet matrix of good physical parameters was created when its temperature decreased to room temperature. In the proposed hot tabletting method, PEG 3000 included in the granulate provided the tableted microcapsules sufficient protection against rupture. Results: The compaction process allowed us to eliminate unwanted physical API properties, which could otherwise have an adverse effect on the fluidized-bed coating process. The microcapsule cores after compaction and coating using a fluidized-bed coating technique showed a THrelease profile similar to that of the compressed microcapsules after applying hot tabletting process. Conclusions: Multi-unit dosage forms can be obtained in a relatively simple way by combining three processes: (i) obtaining TH microcapsule cores by compaction, (ii) coating, and (iii) hot tabletting. © Informa UK, Ltd. Source

Kowalski R.,Medical University of Gdask | Kreft E.,Medical University of Gdask | Kasztan M.,Medical University of Gdask | Jankowski M.,Medical University of Gdask | And 2 more authors.
Nephrology Dialysis Transplantation

Background. Kidney noradrenergic innervation regulates tubular function. Adenosine triphosphate (ATP)-a co-transmitter of norepinephrine-acts on purinoceptors, including ion channel receptor, P2X. P2X receptor agonists, α,β-methylene ATP (α,β-meATP) and β,γ-methylene ATP (β,γ-meATP), induce natriuresis. Regarding the functional co-localization of adrenoceptors and P2X receptors, we evaluated rat renal tubular system sensitivity to natriuretic action of P2X receptor agonists in chronically denervated kidney. Methods. Clearance studies with α,β-meATP and β,γ-meATP (intravenous infusion rate, 2 μmol/kg 20 nmol/kg/min) were performed after bilateral surgical kidney denervation (DNx) and sham-operation (Sham). Na/K-ATPase activity was measured in isolated rat renal proximal tubules. Results. In DNx compared with Sham, saline infusion significantly increased renal sodium and urine excretion and P2X receptor agonist infusion was significantly more natriuretic and diuretic. In DNx and Sham, respectively, α,β-meATP increased fractional excretion of sodium (FENa) by 2 ± 0.3 and 0.6 ± 0.1 and urine (FEV) by 1.6 ± 0.3 and 0.9 ± 0.2; β,γ-meATP had similar effects. In both groups of rats, natriuretic and diuretic actions were abolished by P2 receptor blocker (pyridoxal-phosphate-6-azophenyl-2′, 4′-disulphonate, PPADS), mean arterial blood pressure and glomerular filtration rate remained unchanged during infusion of P2X receptor agonists and antagonist and basal Na/K-ATPase activities in isolated proximal tubules were similar. Both α,β-meATP and β,γ-me-ATP decreased the Na/K-ATPase activity, with 20 inhibition (P < 0.05) in denervated and innervated rats; these inhibitory effects were abolished in the presence of PPADS. Conclusions. Decreased renal sympathetic activity enhances the natriuretic effect of P2X receptor stimulation. This effect is probably not related to altered Na/K-ATPase activity in renal proximal tubules. © 2012 The Author. Source

Szczesio M.,Wroclaw University of Technology | Olczak A.,Wroclaw University of Technology | Goka J.,Wroclaw University of Technology | Gobis K.,Medical University of Gdask | And 2 more authors.
Acta Crystallographica Section C: Crystal Structure Communications

Methyl 2-(pyrazin-2-ylcarbon-yl)hydrazinecarbodithio-ate, C 7H8N4OS2, (E1), N′-[bis- (methyl-sulfan-yl)methyl-idene]pyrazine-2-carbohydrazide, C8H 10N4OS2, (F1), N′-[bis(methyl-sulfan-yl) methyl-idene]-6-meth-oxy-pyrazine-2-carbohydrazide, C9H 12N4O2S2, (F2), and methyl 1-methyl-2-(pyrazin-2-ylcarbon-yl)hydrazinecarbodithio-ate, C 8H10N4OS2, (G1), can be con-sid-ered as derivatives of classical (thio)-amide-type tuber-culo-statics, and all are moderately active against Mycobacterium tuberculosis. This study was undertaken in a search for relationships between activity and specific intra-molecular inter-actions, especially conjugations and hydrogen-bond contacts, and the mol-ecular structures were compared with respective amine analogues, also active against the pathogen. Despite the differences between the amine and carbonyl groups with opposite functions in the hydrogen bond, the two types of structure show a surprisingly similar planar geometry, mostly due to the conjugations aided by the bifurcated intra-molecular hydrogen-bond contact between the N-H group of the central hydrazide group as donor and a pyrazine N atom and an S atom of the dithio function as acceptors. Planarity was suggested to be crucial for the tuberculostatic activity of these compounds. The N-methyl-ated derivative (G1) showed a significant twist at the N-N bond [torsion angle =-121.9 (3)°] due to the methyl substitution, which precludes an intra-molecular N-H⋯S contact and the planarity of the whole mol-ecule. Nonetheless, the compound shows moderate tuberculostatic activity. © 2011 International Union of Crystallography. Source

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