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Search Results: 1 - 10 of 32738 matches for " Daniel Lisak "
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The identification of carbide phases by XRD analysis as the method of assess the extent of the steel damage after long time in service
I. Pietryka,J. Lisak
Archives of Foundry Engineering , 2010,
Abstract: After long time in service in contact in a superheated steam mechanical properties of materials decrease. Experiments revealed that the XRD analysis of electrocemically separated carbide phase is a rapid and informative method of evaluation the service condition of steel. Mechanical properties of ferritic and bainitic low-alloy steels are caused by many factors like: chemical composition, quantity and the kind of microstructural constituent, the precipitation hardening, substructure of matrix and index of matrix lattice defects. In this paper the results of investigations 13CrMo4-5 steel was shown. The material for research was taken from thermal power plant elements. Material A was after 150.000 hours of work as the pressure chamber in which was the temperature 530-580oC and the pressure was 12 MPa. Material B was after 250000 hours of work as the pipeline of superheated steam. The temperature in this case was 530oC but the pressure was 12 MPa as well. The mechanical properties after long time service and changes in fine structure were tested. Parameters of carbide phase electrochemical separation in electrolytes solutions are presented in this work.The most relevant electrolyte and the far better conditions of extraction process were chosen taking into consideration the time needed to get considerable amount of carbide phase constituents. The identification of carbide phases was the special goal of this work. Identification of electrochemically separated carbide phases by means of the XRD analysis was used.
B-Cell-Activating Factor and Autoimmune Myasthenia Gravis
Samia Ragheb,Robert P. Lisak
Autoimmune Diseases , 2011, DOI: 10.4061/2011/939520
Abstract: BAFF is a potent B-cell survival factor, and it plays an essential role in B-cell homeostasis and B-cell function in the periphery. Both normal and autoreactive B cells are BAFF dependent; however, excess BAFF promotes the survival, growth, and maturation of autoreactive B cells. When overexpressed, BAFF protects B cells from apoptosis, thereby contributing to autoimmunity. Three independent studies have shown higher BAFF levels in the circulation of MG patients. BAFF may play an important role in the pathogenesis of MG. BAFF antagonists may well provide new treatment options for MG patients, particularly those patients with thymic lymphoid follicular hyperplasia. 1. Autoimmune Myasthenia Gravis Myasthenia gravis (MG) is a relatively uncommon disease, with an estimated incidence of 100–200 per million in the United States. It is a B-cell-mediated disease in which the target autoantigen is the acetylcholine receptor (AChR) at the postsynaptic membrane of the neuromuscular junction [1–3]. Approximately 85% of patients with generalized MG have circulating anti-AChR antibodies [4–6]. These antibodies are responsible for the pathology of MG, leading to impaired neuromuscular transmission and subsequent muscle weakness that are due to fewer functional AChRs. Some MG patients who are seronegative for anti-AChR have circulating antibodies to muscle-specific kinase (MuSK) [7, 8]. Although these antibodies do not appear to fix complement, MuSK-specific antibodies are pathogenic nevertheless [9–12]. AChR-specific antibodies are heterogeneous in their specificities and can bind to the various subunits of the AChR [13]; however, most are specific for the α-subunit [14, 15]. Interestingly, the loss of functional AChRs leads to increased expression of the α-subunit. It has been suggested that this enhanced expression helps to drive the autoimmune response [16–18]. Thymic abnormalities are found in patients with autoimmune MG. Approximately 70% of MG patients have thymic follicular hyperplasia, 15% have thymomas, and the remainder have a histologically normal thymus for their age. The myasthenic thymus is implicated in initiating or perpetuating the disease process [19–23]. Hyperplasia is associated with early onset of disease. Lymphoid follicular hyperplasia primarily affects the thymic medulla. Germinal centers in the thymic perivascular space are similar to those found in lymph nodes. The presence of these germinal centers indicates that B-cell activation and proliferation are occurring within the myasthenic thymus. The fine specificities of anti-AChR antibodies
Absolute measurement of the ${}^{1}S_{0}$ - ${}^{3}P_{0}$ clock transition in neutral ${}^{88}$Sr over the 330 km-long stabilized fibre optic link
Piotr Morzynski,Marcin Bober,Dobroslawa Bartoszek-Bober,Jerzy Nawrocki,Przemyslaw Krehlik,Lukasz Sliwczynski,Marcin Lipinski,Piotr Maslowski,Agata Cygan,Piotr Dunst,Michal Garus,Daniel Lisak,Jerzy Zachorowski,Wojciech Gawlik,Czeslaw Radzewicz,Roman Ciurylo,Michal Zawada
Physics , 2015, DOI: 10.1038/srep17495
Abstract: We report a stability below $7\times 10{}^{-17}$ of two independent optical lattice clocks operating with bosonic ${}^{88}$Sr isotope. The value (429228066418008.3(1.9)${}_{syst}$(0.9)${}_{stat}$~Hz) of the absolute frequency of the ${}^{1}S_{0}$ - ${}^{3}P_{0}$ transition was measured with an optical frequency comb referenced to the local representation of the UTC by the 330 km-long stabilized fibre optical link. The result was verified by series of measurements on two independent optical lattice clocks and agrees with recommendation of Bureau International des Poids et Mesures.
Role of Neuropoietic Cytokines in Development and Progression of Diabetic Polyneuropathy: From Glucose Metabolism to Neurodegeneration
Dusanka S. Skundric,Robert P. Lisak
Experimental Diabetes Research , 2003, DOI: 10.1155/edr.2003.303
Abstract: Diabetic neuropathy develops as a result of hyperglycemia- induced local metabolic and microvascular changes in both type I and type II diabetes mellitus. Diabetic neuropathy shows slower impulse conduction, axonal degeneration, and impaired regeneration. Diabetic neuropathy affects peripheral, central, and visceral sensorimotor and motor nerves, causing improper locomotor and visceral organ dysfunctions. The pathogenesis of diabetic neuropathy is complex and involves multiple pathways. Lack of success in preventing neuropathy, even with successful treatment of hyperglycemia, suggests the presence of early mediators between hyperglycemia-induced metabolic and enzymatic changes and functional and structural properties of Schwann cells (SCs) and axons. It is feasible that once activated, such mediators can act independently of the initial metabolic stimulus to modulate SC-axonal communication. Neuropoietic cytokines, including interleukin-1 (IL-1), interleukin-6 (IL-6), leukemia inhibitory factor (LIF), ciliary neurotrophic factor (CNTF), tumor necrosis factor alpha (TNF-α), and transforming growth factor beta (TGF- β), exhibit pleiotrophic effects on homeostasis of glia and neurons in central, peripheral, and autonomic nervous system. These cytokines are produced locally by resident and infiltrating macrophages, lymphocytes, mast cells, SCs, fibroblasts, and sensory neurons. Metabolic changes induced by hyperglycemia lead to dysregulation of cytokine control. Moreover, their regulatory roles in nerve degeneration and regeneration may potentially be utilized for the prevention and/or therapy of diabetic neuropathy.
Coherent instabilities of intense high-energy "white" charged-particle beams in the presence of nonlocal effects within the context of the Madelung fluid description
R. Fedele,D. Anderson,M. Lisak
Physics , 2005, DOI: 10.1140/epjb/e2006-00067-3
Abstract: A hydrodynamical description of coherent instabilities that take place in the longitudinal dynamics of a charged-particle coasting beam in a high-energy accelerating machine is presented. This is done in the framework of the Madelung fluid picture provided by the Thermal Wave Model. The well known coherent instability charts in the complex plane of the longitudinal coupling impedance for monochromatic beams are recovered. The results are also interpreted in terms of the deterministic approach to modulational instability analysis usually given for monochromatic large amplitude wave train propagation governed by the nonlinear Schr\"odinger equation. The instability analysis is then extended to a non-monochromatic coasting beam with a given thermal equilibrium distribution, thought as a statistical ensemble of monochromatic incoherent coasting beams ("white" beam). In this hydrodynamical framework, the phenomenon of Landau damping is predicted without using any kinetic equation governing the phase space evolution of the system.
Effect of high hydrostatic pressure, ultrasound and pulsed electric fields on milk composition and characteristics
Irena Jeli?i?,Katarina Lisak,Rajka Bo?ani?
Mljekarstvo , 2012,
Abstract: High hydrostatic pressure, ultrasonication and pulsed eletrcic fields (PEF) belong to novel food processing methods which are mostly implemented in combination with moderate temperatures and/ or in combination with each other in order to provide adequate microbiological quality with minimal losses of nutritional value. All of three mentioned methods have been intensively investigated for the purpose of inactivation and reduction of foodborne microorganisms present in milk and dairy products. However, a large number of scientific researches have been dedicated to investigation of impact of these methods on changes in constituents like milk fat, milk proteins and lactose as well as changes in mechanisms like renneting properties and coagulation of milk. The aim of this research was to give an overview of changes in milk constituents induced by high hydrostatic pressure, ultrasonification and pulsed electric field treatments as well as to suggest how these changes could improve conventional processes in the dairy industry.
Impact of enzymatic hydrolyzed lactose on fermentation and growth of probiotic bacteria in whey
Bojan Matijevi?,Katarina Lisak,Rajka Bo?ani?,Ljubica Tratnik
Mljekarstvo , 2011,
Abstract: Taking in consideration the long time for whey fermentation using probiotic bacteria, the aim of this research was to determine if prior enzymatic hydrolysis of lactose influences microbial activities of Lactobacillus acidophilus La-5 or Bifidobacterium animalis subsp. lactis BB-12 in reconstituted sweet whey. During fermentation (at 37 °C), pH-value and viable cell counts were monitored. The fermented samples were sensory profiled. Lactose hydrolysis shortened the fermentation time of Lactobacillus acidophilus La-5 by 2 h, and viable cell count at the end of fermentation time was greater in hydrolyzed whey sample (~9.45 log10 CFU/mL) when compared with the control sample (~8.91 log10 CFU/mL). In contrast, lactose hydrolysis in whey did not enhance the activity of Bifidobacterium animalis subsp. lactis BB-12. Lactose hydrolysis had slightly influence on sensory score of fermented samples, probably due to sweetness that masked the acidic taste of the product.
The influence of the different initial probiotic bacteria concentration on sweet whey fermentation
Bojan Matijevi?,Katarina Lisak,Rajka Bo?ani?,Ljubica Tratnik
Mljekarstvo , 2008,
Abstract: Whey is nutritiously very high-quality secondary product from cheese making which is not used enough in human diet. When the fermentation is performed with probiotic bacteria it additionally increases its nutritional and health values. This research examines the influence of different amount of inoculum addition (2.5, 5 and 7.5 %) of monoculture Lactobacillus acidophilus La-5 or Bifidobacterium animalis subsp. lactis BB-12, on the course of fermentation of reconstitued sweet whey at 37 °C. During fermentation and 28 days of cool storage fermented whey pH value, titratable acidity and the viable cells count was monitored. Fermentation with 7.5 % inoculum of monoculture Lactobacillus acidophilus La-5 lasted the shortest (about 13.3 hours), while the fermentation with 2.5 % inoculum lasted the longest (about 15.5 hours). The viable cells count of Lactobacillus acidophilus La-5 cells in all whey samples has increased during fermentation for about 1.3 log CFU/mL and at the end of fermentation was about 8.5 log CFU/mL. Whey fermentation with 7.5 % added inoculum of monoculture Bifidobacterium animalis subsp. lactis BB-12 showed no difference in duration time in comparison to whey fermentation with 2.5 % inoculum addition. The viable cells count of Bifidobacterium animalis subsp. lactis BB-12 has increased during fermentation for about 0.9 log CFU/mL and at the end of fermentation was about 8.7 log CFU/mL. The amount of inoculum had no influence on survival of probiotic bacteria in fermented whey regardless of monoculture used.
Influence of sweetener stevia on the quality of strawberry flavoured fresh yoghurt
Katarina Lisak,Irena Jeli?i?,Ljubica Tratnik,Rajka Bo?ani?
Mljekarstvo , 2011,
Abstract: Stevia is a natural, non energetic sweetener, 200-300 times sweeter than sucrose, and is obtained by leaves extraction of the Stevia rebaudiana. According to the low energy value of stevia to sweeten food products, it is a great possibility of its use in the dairy industry. This study examined the differences in the sweetness of the strawberry flavoured yoghurt with the addition of sucrose, stevia and equal portions of sucrose and stevia; each combination was used at three different concentrations (3, 4.5 and 6 % / 100 g yoghurt). Stevia was diluted in a concentration which, according to the literature, matches the sweetness profile of sucrose. Viscosity of the yoghurts was determined by the rheometer, and sensory profiling of the products was evaluated by a panel using the ranking test and weighted factors methods. The level of sweetness of all yoghurt samples (using sucrose, stevia and mixture of sucrose and stevia) was judged by a test panel, and products were rated in the terms of degree of sweetness as sucrose > sucrose + stevia > stevia. The recommended level by panelists of any type or combination of sweeteners for strawberry yoghurt was 4.5 g sweetner/100 g. The apparent viscosity was lower in sucrose yoghurts compared to products made with stevia or stevia + sucrose which was also reflected in the sensory scores.
Co--propagating Bose--Einstein Condensates and electromagnetic radiation: Emission of mutually localized structures
Arkady Kim,Federica Cattani,Dan Anderson,Mietek Lisak
Physics , 2010, DOI: 10.1103/PhysRevA.83.013608
Abstract: Using a semi-classical model to describe the interaction between coherent electromagnetic radiation and a Bose-Einstein condensate in the limit of zero temperature, including the back action of the atoms on the radiation, we have analyzed the phenomenon of emission of solitary-like wave packets which can accompany the formation of mutually localized atom-laser structures.
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