Wyniki wyszukiwania - Biblioteka Nauki

1

Kinematyka węzła ciernego na przykładzie łożyskowania igiełkowego

100%

Nachimowicz J. , Korbut R.

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tom z. 83

163--171

PL

Niniejszy artykuł dotyczy zjawisk zachodzących w łożyskowaniu igiełkowym. Tarcie generujące moment oporu pracy węzła ciernego jest głównym czynnikiem mającym wpływ na jego zużycie. W łożysku igiełkowym mamy do czynienia z dwoma wiodącymi rodzajami tarcia: tarciem tocznym i tarciem poślizgu, i te właśnie procesy są głównym przedmiotem badań. W pracy przedstawiono wyniki z rejestracji i analizy ruchu wszystkich elementów tocznych w łożyskowaniu. Doświadczenia przeprowadzono na stanowisku badawczym możliwie dokładnie oddającym warunki realnej pracy łożyska. Odpowiednio przygotowana metodyka badań pozwala na pomiar i analizę oporu ruchu łożyska, określenie strefy czynnego przenoszenia obciążenia i wyznaczenie współczynników tarcia.

EN

The present study concerns certain phenomena that take place in the needle roller bearing. The friction that generates the anti-torque of a friction pair is the major factor that influences the needle bearing’s wear. In the needle bearing there occur two predominant types of friction: the rolling friction and the sliding friction, and both are subject to examination. The study presents recordings and analysis of the movements of all needle bearing’s rolling elements. The examination was carried out on a special examination stand that precisely emulates the real conditions of the needle bearing’s work. Carefully prepared examination methods enable recording and analyzing frictions in the bearing, estimating a sphere within which the load is shifted, and calculating the coefficient of friction.

2

Stanowisko do modelowania procesu tarcia w łożyskowaniu igiełkowym

100%

Nachimowicz J. , Korbut R.

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tom T. 16, nr 2

67-71

PL

W pracy przedstawiono stanowisko przeznaczone do badania procesu tarcia i zużycia w łożyskowaniu igiełkowym. Prezentowane stanowisko pozwala zarejestrować prędkości obrotowe wałka i igiełek, moment tarcia oraz wydzielające się ciepło. Zmiana obciążenia, środowiska pracy oraz prędkości obrotowej w połączeniu ze zmienną geometrią elementów współpracujących w węźle tarciowym, pozwala na zbadanie wpływu tych parametrów na moment tarcia i zużycie. Obecnie nie istnieje powszechnie funkcjonująca metoda umożliwiająca określenie tarcia poślizgu w łożyskowaniu igiełkowym - zatem budowa stanowiska jest zasadna.

EN

The article introduces a stand designed for examining the process of friction and wear in the needle bearing. The device enables us to record the rotational speed of the shaft neck and needle rollers, the moment of friction and the heat emitted. Alterations in the load, the working environment and the rotational speed combined with changing geometry of cooperating elements in the friction pair make it possible to estimate the influence of these parameters on the moment of friction and the degree of wear. At present there is no commonly accepted method of measuring the needle spin in the needle bearing, which means that constructing the stand is justifiable.

3

Anti-aggregatory prostanoids. Part II

100%

Korbut R. , Gryglewski R. J.

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nr 5-6

4

The Analysis of Friction Surfaces of the Needle Bearing Elements

100%

Nachimowicz J. , Korbut R.

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tom Vol. 34, No. 1

92-100

EN

The article describes the changes in the surface area of contact two rolls with parallel axes: needles bearing and pin shaft. The study of factors affecting the surface area of contact elements cooperating: changing needles and shaft diameters, changing the values of Young modulus, Poisson ratio of materials, and changing load. Properties which are typical of deformed sections of friction surface have essential influence on the durability of the elements of friction couple. It is crucial to make the right choice of materials for friction elements and analysis of these elements. The conditions of transition were definite from the normal wear to pathological wear. It was done through determinate critical parameters such as: the value of clearance in connection, the intensity of wear in function of load.

5

Examination of the Abrasiveness of Vehicle Lacquer Coats

80%

Nachimowicz J. , Korbut R. , Rydzewski M.

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2017

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tom Vol. 41, No. 3

83--94

EN

The present paper shows the results of the examination of particular vehicle lacquer coats in terms of their abrasiveness. The tests were carried out on the tribological examination stand T-20, which, as a friction pair, used a rolling ball made of the 17HNM steel and an immobile shield covered with a complete lacquer coat. Moreover, the paper presents the method of selecting optimum parameters of friction, as well as the results of the abrasiveness examination of water-based lacquers and classic lacquers with classic solvents.

6

Perivascular adipose tissue as a messenger of the brain-vessel axis: role in vascular inflammation and dysfunction

80%

Guzik T. J. , Marvar P. J. , Czesnikiewicz-Guzik M. , Korbut R.

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tom 58

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nr 4

7

Effects of nitric oxide and prostacyclin on deformability and aggregability of red blood cells of rats ex vivo and in vitro

80%

Starzyk D. , Korbut R. , Gryglewski R. J.

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tom 50

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nr 4

8

Mouse models of experimental atherosclerosis

80%

Jawien J. , Nastalek P. , Korbut R.

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tom 55

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nr 3

EN

Since 1992 the mouse has become an excellent model for experimental atherosclerosis research. Until 1992, the diet - induced atherosclerosis mouse model has been used effectively, but the lesions tended to be small and were limited to early fatty-streak stage. This model was also criticized because of the toxicity and inflammatory responses due to the diet. In 1992 the first line of gene targeted animal models, namely apolipoprotein E - knockout mice was developed. Of the genetically engineered models, the apoE - deficient model is the only one that develops extensive atherosclerotic lesions on a chow diet. It is also the model in which the lesions have been characterized most thoroughly. The lesions develop into fibrous plaques; however, there is no evidence that plaque rupture occurs in this model. The LDL receptor - deficient model has elevated LDL levels, but no lesions, or only very small lesions, form on the chow diet, however, robust lesions do form on the western-type diet. The creation of apoE - knockout mice has changed the face of atherosclerosis research.

9

Endothelial secretogogues and deformability of erythrocytes

80%

Korbut R. A. , Adamek-Guzik T. , Madej J. , Korbut R.

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tom 53

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nr 4,1

EN

Many diseases of the heart and circulatory system have been linked with both dysfunction of vascular endothelium and insufficient deformability of erythrocytes. Using shear stress laser diffractometry we investigated whether deformability of erythrocytes would be regulated endogenously by generation of two endothelial secretogogues: prostacyclin and nitric oxide. Experiments were performed in rats ex vivo and with whole blood or isolated erythrocytes in vitro. Iloprost - a stable analogue of prostacyclin (10 µg/kg i.v.) and SIN-1 (NO-donor) at a dose of 2 mg/kg/min i.v induced a significant improvement of deformability of erythrocytes ex vivo. Improvements of deformability by these two compounds were also evident in vitro when they were applied at a range of concentrations of 1 µM and 3 µM, respectively. Cyclooxygenase (indomethacin 20 mg.kg i.v.) and nitric oxide synthase (L-NAME 10 mg/kg i.v.) inhibitors while worsening deformability ex vivo, they did not affect (3 mM and 10 µM, respectively) rheological functions of erythocytes in vitro. Aggravating effects of these inhibitors on erythrocyte deformability ex vivo were reversed by prostacyclin and nitric oxide supplemented exogenously. Aspirin at a low (1 mg/kg i.v.) and high dose (50 mg/kg i.v.), contrary to indomethacin and L- NAME, aggravated erythrocyte deformability either ex vivo or in vitro. It is concluded that autocrine function of vascular endothelium plays an important role in regulation of rheology of red blood cells in flowing blood. The mechanism of this phenomenon is unclear but some possible explanations are discussed. In addition, in our experiments aspirin revealed unique erythrocyte damaging properties, possibly independent of inhibition of cyclooxygenase, but related to a direct protein acetylation.

10

Nitric oxide and superoxide in inflammation and immune regulation

80%

Guzik T. J. , Korbut R. , Adamek-Guzik T.

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nr 4

EN

Nitric oxide (NO) and reactive oxygen species exert multiple modulating effects on inflammation and play a key role in the regulation of immune responses. They affect virtually every step of the development of inflammation. Low concentrations of nitric oxide produced by constitutive and neuronal nitric oxide synthases inhibit adhesion molecule expression, cytokine and chemokine synthesis and leukocyte adhesion and transmigration. Large amounts of NO, generated primarily by iNOS can be toxic and pro-inflammatory. Actions of nitric oxide are however not dependent primarily on the enzymatic source, but rather on the cellular context, NO concentration (dependent on the distance from NO source) and initial priming of immune cells. These observations may explain difficulties in determining the exact role of NO in Th1 and Th2 lymphocyte balance in normal immune responses and in allergic disease. Similarly superoxide anion produced by NAD(P)H oxidases present in all cell types participating in inflammation (leukocytes, endothelial and other vascular cells etc) may lead to toxic effects, when produced at high levels during oxidative burst, but may also modulate inflammation in a far more discrete way, when continuously produced at low levels by NOXs (non-phagocytic oxidases). The effects of both nitric oxide and superoxide in immune regulation are exerted through multiple mechanisms, which include interaction with cell signalling systems like cGMP, cAMP, G-protein, JAK/STAT or MAPK dependent signal transduction pathways. They may also lead to modification of transcription factors activity and in this way modulate the expression of multiple other mediators of inflammation. Moreover genetic polymorphisms exist within genes encoding enzymes producing both NO and superoxide. The potential role of these polymorphisms in inflammation and susceptibility to infection is discussed. Along with studies showing increasing role of NO and free radicals in mediating inflammatory responses drugs which interfere with these systems are being introduced in the treatment of inflammation. These include statins, angiotensin receptor blockers, NAD(P)H oxidase inhibitors, NO-aspirin and others. In conclusion in this mini-review we discuss the mechanisms of nitric oxide and superoxide dependent modulation of inflammatory reactions in experimental animals and humans. We also discuss potential roles of nitric oxide as a mediator of allergic inflammation.

11

Adipocytokines - novel link between inflammation and vascular funktion?

80%

Guzik T. J. , Mangalat D. , Korbut R.

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nr 4

EN

Obesity and obesity related diseases are a major public health problem. Recent studies have shown that fat tissue is not a simple energy storage organ, but exerts important endocrine and immune functions. These are achieved predominantly through release of adipocytokines, which include several novel and highly active molecules released abundantly by adipocytes like leptin, resistin, adiponectin or visfatin, as well as some more classical cytokines released possibly by inflammatory cells infiltrating fat, like TNF-alpha, IL-6, MCP-1 (CCL-2), IL-1. All of those molecules may act on immune cells leading to local and generalized inflammation and may also affect vascular (endothelial) function by modulating vascular nitric oxide and superoxide release and mediating obesity related vascular disorders (including hypertension, diabetes, atherosclerosis, and insulin resistance) but also cancer or non-alcoholic fatty liver diseases. Present review, in a concise form, focuses on the effects of major adipocytokines, characteristic for adipose tissue like leptin, adiponectin, resistin and visfatin on the immune system, particularly innate and adaptive immunity as well as on blood vessels. Macrophages and T cells are populating adipose tissue which develops into almost an organized immune organ. Activated T cells further migrate to blood vessels, kidney, brain and other organs surrounded by infiltrated fat leading to their damage, thus providing a link between metabolic syndrome, inflammation and cardiovascular and other associated disorders. Ceretain treatments may lead to significant changes in adipocytokine levels. For example include beta-2 adrenoreceptor agonists, thiazolidinediones as well as androgens lead to decrease of plasma leptin levels. Moreover future treatments of metabolic system associated disorders should focus on the regulation of adipocytokines and their modes of action.

12

The current view on biological potency of cationically modified chitosan

61%

Stefan J. , Lorkowska-Zawicka B. , Kaminski K. , Szczubialka K. , Nowakowska M. , Korbut R.

Journal of Physiology and Pharmacology

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2014

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tom 65

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nr 3

13

The effect of montelukast on atherogenesis in APOE-LDLR-double knockout mice

61%

Jawien J. , Gajda M. , Wolkow P. , Zuranska J. , Olszanecki R. , Korbut R.

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nr 3

633-639

EN

We have shown that inhibitors of five lipoxygenase activating protein (FLAP) - MK-886 and BAYx1005 inhibit atherosclerosis in apolipoprotein E / LDL receptor - double knockout mice. We, therefore, investigated whether cysteinyl leukotrienes receptor inhibitor - montelukast, given at a dose of 0.125 µg per 100 mg of body weight per day during 16 weeks, could also attenuate atherogenesis. In apoE/LDLR - DKO mouse model montelukast significantly decreased atherogenesis, measured both by "en face" method (25.5±2.% vs. 17.23 ± 1.8%) and "cross-section" method (455 494 ± 26 477 µm2 vs. 299 201 ± 20 373 µm2). The results were, however, less pronounced, comparing to FLAP inhibitors. This is the first report showing the effect of montelukast on atherogenesis in gene-targeted mice.

14

AVE 0991 - angiotensin-(1-7) receptor agonist, inhibits atherogenesis in apoE - knockout mice

51%

Toton-Zuranska J. , Gajda M. , Pyka-Fosciak G. , Kus K. , Pawlowska M. , Niepsuj A. , Wolkow P. , Olszanecki R. , Jawien J. , Korbut R.

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nr 2

EN

Recent evidence shows that the renin-angiotensin system is a crucial player in atherosclerotic processes. It was also proved that Ang II promotes atherogenesis. Angiotensin-(1-7) [Ang-(1-7)] opposites Ang II action. Therefore, we would like to find out whether Ang-(1-7) receptor agonist: AVE 0991, could ameliorate atherosclerosis progression in an experimental model of atherosclerosis: apolipoprotein E (apoE) - knockout mice. AVE 0991 inhibited atherogenesis, measured both by “en face” method (7.63±1.6% vs. 14.6±2.1%) and “cross-section” method (47 235±7 546 µm2 vs. 91 416±8 357 µm2). This is the first report showing the effect of AVE 0991 on atherogenesis in gene-targeted mice.

15

New cationically modified pullulan attenuates atherogenesis and influences lipid metabolism in apoE-knockout mice

51%

Stefan J. , Kus K. , Wisniewska A. , Kaminski K. , Szczubialka K. , Jawien J. , Nowakowska M. , Korbut R.

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nr 5

16

Inhibition of nuclear factor-kappaB attenuates atherosclerosis in apoE-LDLR - double knockout mice

51%

Jawien J. , Gajda M. , Mateuszuk L. , Olszanecki R. , Jakubowski A. , Szlachcic A. , Karabiowska M. , Korbut R.

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nr 3

EN

Nuclear factor - B (NF-B) is a good therapeutic target for cardiovascular disease and numerous efforts are being made to develop safe NF-B inhibitors. Nowadays many authors address NF-B as a major therapeutic target in atherosclerosis, especially for preventive measures, in the light of two main hypothesis of atherosclerosis: oxidation and inflammation. We hypothesized that ammonium pyrrolidinedithioocarbamate (PDTC) - a well-known inhibitor of NF-B could inhibit the development of atherosclerosis in this experimental model. We used apoE/LDLR - DKO mouse model, which is considered as a one of the best models to study the anti-atherosclerotic effect of drugs. In this model PDTC inhibited atherogenesis, measured both by "en face" method (25,15±2,9% vs. 15,63±0,6%) and "cross-section" method (565867±39764 µm2 vs. 291695±30384 µm2). Moreover, PDTC did not change the profile of cholesterol and triglycerides in blood. To our knowledge, this is the first report that shows the effect of PDTC on atherogenesis in gene-targeted apoE/LDLR - double knockout mice.

17

NADPH oxidase and uncoupled nitric oxide synthase are major sources of reactive oxygen species in oral squamous cell carcinoma. Potential implications for immune regulation under high oxidative stress conditions.

51%

Czesnikiewicz-Guzik M. , Lorkowska B. , Zapala J. , Czajka M. , Szuta M. , Loster B. , Guzik T. J. , Korbut R.

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nr 1

EN

The development of cancer is associated with high oxidative stress and at the same time with immune system activation. Tumors develop efficient mechanisms of protection against the immune response, which allow them to escape the immune surveillance. Simultaneously, key events in the process of carcinogenesis are related to oxidative stress. The relationship between the two remains unknown. Novel understanding of oxidative stress shows that discrete changes of activities of certain enzyme systems such as NADPH oxidases or nitric oxide synthases may be more important than the overall balance of production and removal of reactive oxygen species. Such imbalance of nitric oxide and superoxide production could modify inflammation and immune regulation. We studied superoxide anion production (by lucigenin enhanced chemiluminescence - 5 µM), NADPH oxidase activity and nitric oxide synthase (NOS) dysfunction. In parallel mRNA expression of immunomodulatory markers such as FoxP3 (T regulatory cell marker), CCR6 (mucosal homing effector T cell marker) and CD85j (NK cell/CD8 T cell Ig-like MHC class I inhibitory receptor) was determined. Basal superoxide production and NADPH oxidase activity are increased in oral squamous cell carcinoma. Tumor superoxide production was inhibited by NADPH oxidase inhibitor apocynin and by NOS inhibitor L-NAME. This indicates, for the first time, that oral squamous cell carcinoma is characterized by dysregulated nitric oxide synthase, which apart from increased NADPH oxidase activity contributes to oxidative stress and may be related to the immuno-pathology of these tumors. Studied tumors were infiltrated by CCR6+, but showed lower expression of both CD85j and FoxP3 mRNA. Finally, the CD85j mRNA expression was inversely correlated to oxidative stress parameters. These preliminary studies indicate that tumor oxidative stress, related to NADPH oxidase activity and NOS activity could be related to immune responses to cancer, thus therapeutic modification of oxidative stress, which could include the correction of NOS dysfunction, could facilitate immune surveillance.

18

The effect of nebivolol on atherogenesis in apoE - knockout mice

41%

Kus K. , Gajda M. , Pyka-Fosciak G. , Toton-Zuranska J. , Pawlowska M. , Suski M. , Niepsuj A. , Nowak B. , Wolkow P. , Olszanecki R. , Jawien J. , Korbut R.

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nr 4

163-165

EN

Nebivolol is a novel beta1-blocker with a nitric oxide (NO) - potentiating, vasodilatory effect that is unique among beta-blockers. It was already shown that nebivolol ameliorates atherosclerosis in cholesterol-fed rabbits. We, therefore, wanted to investigate whether this is the case in the fine experimental model of atherosclerosis: apolipoprotein E (apoE)- knockout mice. Nebivolol attenuated atherogenesis, measured both by "en face" method (9.23±1.8% vs. 14.6±2.1%) and "cross-section" method (63125±8455 µm2 vs. 91416±8357 m2). This is the first report showing the effect of nebivolol on atherogenesis in gene-targeted mice.