Wyniki wyszukiwania - Biblioteka Nauki

1

Application of modified Ritchie-Knott-Rice criterion to cellular automata

100%

Janus-Gałkiewicz U. , Neimitz A.

Journal of Theoretical and Applied Mechanics

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2019

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tom Vol. 57 nr 3

577--590

EN

In this paper, the cellular automata model is applied to analyse cleavage and ductile fracture in front of a crack in three-point-bend specimens made of Hardox-400 steel. The research programme was composed of experiments followed by fractographic and numerical analyses. On the basis of microscopic observations, the sizes of cells used in the automata were determined. The algorithm enabled mapping of the two-dimensional crack surface as well as a simulation of temperature-dependent failure mechanisms by defining transition rules based on the modified Ritchie-Knott-Rice cleavage fracture criterion. The critical stress values were estimated and verified by the cellular automata model.

2

Structural domains of plant nuclear DNA as a constitutive component of the topoisomerase II-DNA complex

88%

Solovyan V. T. , Andreyev I. O.

Acta Biochimica Polonica

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1995

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tom 42

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nr 2

EN

The treatment of agarose embedded plant nuclei by strong protein dénaturants was demonstrated to result in discrete self-fragmentation of intact nuclear DNA. The set of resultant DNA cleavage products involves two main types of DNA fragments sized about 50-100 kb and 300-500 kb, being of the same type in various eukaryotic representatives. The pattern of ordered DNA fragmentation has been shown to be similar both in intact nuclei and in histone-depleted ones thus suggesting that the observed DNA fragments represent preexisting DNA structural domains, corresponding to the higher levels of chromatin folding. The topoisomerase II-speeific poison teniposide (VM-26) has been shown to increase the ordered DNA cleavage while the conditions stimulating the topoisomerase II-mediated reverse reaction lead to the reassociation of the cleaved DNA domains. The data presented suggest that the nuclear DNA structural domains are involved in functioning of the topoisomerase II/DNA complex, the main property of which is its ability to mediate the cleavage/ /reassociation reactions.

3

Acid-Catalyzed Cleavage of Some Chromone, Coumarin and Pyrone Derivaties of Aminomethylphosphonic Acid. Products and Kinetics of the ReactionB

75%

Boduszek B. , Latajka R. , Walkowiak U.

Polish Journal of Chemistry

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2001

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tom Vol. 75, nr 1

63-69

EN

Treatment of chromone-2, coumarin-4 and pyrone-2 derivatives of N-benzylaminomethylphosphonic acid with strong mineral acids leads to formation of the corresponding heterocyclic amines and phosphoric acid. Kinetic studies of this cleavage reaction demonstrate that protonation has a remarkable influence on a cleavage of C-P bonds. In aq. H2SO4, cleavage of the acids 1-3 exhibits a kinetic dependence on [H+]. The measured solvent isotope effect (kH/kD) was about 1.5 for the 1 and 2 and only 1.1 for the 3. The existence of the isotope effect shows that protons are involved on the rate-determining step. The data obtained suggest that the protonated phosphonate molecule is split by a dissociative mechanism with A-SE2 character and this is combined with an elimination of the phosphonate group as a positive-charged phosphorus moiety.

4

Oocyte maturation in the presence of randomly pooled follicular fluid increases bovine blastocyst yield in vitro

75%

Mohammed A. A. , Karasiewicz J. , Papis K. , Modlinski J. A.

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tom 14

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nr 3

501-512

5

Specificity and mechanism of the cleavages induced in yeast tRNAPhe by magnesium ions

75%

Marciniec T. , Ciesiolka J. , Wrzesinski J. , Wiewiorowski M. , Krzyzosiak W. J.

Acta Biochimica Polonica

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1989

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tom 36

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nr 3-4

6

Predetermination of cytokinesis and transition from holoblastic to partial superficial cleavage in early embryonic development of Tetrodontophora bielanensis [Collembola]

75%

Klag J. , Krzysztofowicz A. , Jura C. , Kisiel E.

Folia Biologica

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2000

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tom 48

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nr 3-4

7

Stereological analysis of mitochondria in embryos of Rana temporaria and Bufo bufo during cleavage

75%

Romek M. , Krzysztofowicz E.

Folia Histochemica et Cytobiologica

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2005

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tom 43

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nr 1

8

Karyomere formation in cleaving eggs of Tetrodontophora bielanensis [Collembola]

75%

Klag J. , Jura C. , Krzysztofowicz A. , Kisiel E.

Folia Biologica

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1995

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tom 43

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nr 1-2

9

Cleavage of prothrombin bound in immune complexes results in high thrombin enzymatic activity

75%

Pajdak W. , Radwan J. , Guzik T. J.

Journal of Physiology and Pharmacology

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2004

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tom 55

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nr 2

EN

Thrombin plays a pivotal role in blood clotting as well as in the regulation of vascular remodeling and oxidative stress. Recent evidence suggests that auto-antibodies directed against prothrombin, may play an important role in the pathogenesis of atherosclerosis. It is however not clear, if prothrombin bound in an immune complex retains its clotting and regulatory properties or acts solely by increasing vascular inflammation. In order to answer this question, we used a newly developed stain for the detection of thrombin activity of such complexes. Plasma and serum samples were subjected to rocket immunoelectrophoresis in an anti-prothrombin antiserum containing agarose gel. Gel plates, covered with a nitrocellulose membrane were soaked with chromogenic thrombin substrate. The product of thrombin activity was diazotized to red azo dye bound to nitrocellulose. Activity stain revealed barely discernible rockets in plasma, but heavily stained ones in serum. Pre-incubation with trypsin enhanced activity of immunoprecipitates deriving from plasma, but not from serum. Densitometric analysis showed, that the trypsin-enhanced activity in plasma derived immune complexes was twice as high as in serum derived immunoprecipitates. Thrombin active centre is not blocked by anti-prothrombin antiserum allowing to retain thrombin activity. Moreover, prothrombin in immunoprecipitate is readily cleaved by proteolytic enzymes. This cleavage could potentially be enhanced by antibody binding, although these results need to be confirmed using different antibodies.

10

Holoblastic early cleavage of Tetrodontophora bielanensis [Collembola] eggs, with special reference to its irregularity

75%

Klag J. , Jura C. , Krzysztofowicz A. , Kisiel E.

Folia Histochemica et Cytobiologica

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1999

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tom 37

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nr 3

11

Wpływ łupności na stan naprężenia i deformacji w górotworze

63%

Patyńska R.

WUG : bezpieczeństwo pracy i ochrona środowiska w górnictwie

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2006

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tom nr 6

48-49

PL

Uznając za istotną rolę czynnika naturalnego - struktury górotworu i wzajemnego usytuowania płaszczyzn osłabionej spoistości górotworu, w generowaniu wstrząsów o wysokiej energii - dotychczas nie opracowano wiarygodnego modelu deformacji i naprężenia w górotworze, który pozwoliłby w pełni korelować wyniki badań nad sejsmicznością obszaru i tektoniką regionalną. Określenie charakteru takich związków w oparciu o przedstawiony model geomechaniczny stanu naprężeniowo-deformacyjnego górotworu , może pozwolić na szacowanie zasięgu zjawisk sejsmicznych, a tym samym zastosowanie odpowiednich metod profilaktycznych.

EN

Although the role of natural factors - rock mass structure and interacting location of planes of weakened rock mass cohesion - played in generating high energy tremors has generally been accepted, a reliable model of rock mass state of stress and deformation which could allow the results of the studies on seismicity and regional tectonics of the area to be fully correlated has not been developed, as jest. Therefore, defining the nature of such relationships from the presented geomechanical model of stress-strain relations of rock masses will allow assessment of the extent of effects of seismic events and use of the appropriate preventive measures.

12

The level of non-hydrophobic lipids in pig embryos during cleavage

63%

Romek M. , Gajda B. , Weber P. , Krzysztofowicz E. , Smorag Z.

Acta Biologica Cracoviensia. Series Botanica. Supplement

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2008

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tom 50

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nr 1

13

Scanning electron microscopy of the egg surface of the common toad, Bufo bufo, following fertilization and during first cleavage

63%

Semik D. , Kilarski W.

Folia Histochemica et Cytobiologica

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1998

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tom 36

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nr 1

14

Utilization of yolk platelets during early embryonic development of Rana temporaria and Bufo bufo

63%

Romek M. , Krzysztofowicz E.

Folia Histochemica et Cytobiologica

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2001

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tom 39

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nr 3

15

Od afery Rywina do katastrofy smoleńskiej - nowe (utrwalone) podziały społęczno-polityczne w Polsce

51%

Bejma A.

Studia Politologiczne

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2013

|

tom 29

112-132

PL

Celem artykułu jest próba uchwycenia nowych stymulatorów podziału społeczeństwa polskiego, bowiem utrzymujący się od początku przemian transformacyjnych, dość stabilny historyczny podział na obóz poskomunistyczny i postsolidarnościowy, po 14-stu latach przestał odgrywać pierwszoplanową rolę.

EN

This article's aim is to outline the stimulators of the division of Polish society.

16

Crack habits in metal/hydrogen interactive systems

51%

Katz Y.

Journal of Achievements in Materials and Manufacturing Engineering

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2015

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tom Vol. 73, nr 2

144--150

EN

Purpose: In terms of structural integrity aspects, interactive insights into metal/hydrogen systems become self-explanatory. In fact, ample of local critical events are involved namely, from sub-critical slow crack growth up to a total delayed failure. Design/methodology/approach: Mainly, crack-tip vicinity characterization became essential from both, chemical and mechanical factors, as related to the complicated aspects of crack stability. Note that the interactive situation has been currently investigated, imposing as such new local conditions. In fact, the current study adopted a highly comprehensive methodology in view of fracture physics. Thus, the material selection included iron-based (Fe-3%Si) and zinc single crystals. For the sake of background only, polycrystalline austenitic stainless steels were also investigated regarding hydrogen interaction affecting mechanical properties. Hydrogen charging has been performed either by electrolytic cathodic charging or, by high temperature/pressure gaseous methods. Fracture mechanics methodology was mainly implemented by utilizing external or internal hydrogen interaction procedures. Experimentally, research activities have been conducted by novel techniques, such as ultra-high visualization techniques and by using basic plasticity information like crack-tip dislocation emission and structures. Findings: Enhanced crack extension was established and the slow subcritical crack extension was traced in physically well-defined crack systems. Fracture mode transitions occurred due to the deformation/environment interaction. For example, in iron-based single crystals the unique cleavage mode emphasized the embrittlement impact. The broadness of the current study enabled a more local fundamental approach aimed to understand the crack-path habits. Here, the role of the crack-tip shielding beside the crack arrest potentials have been considered. Research limitations/implications: The dominating micro-mechanisms of hydrogen-related fracture have been thoroughly reviewed in the literature. Despite the remarkable research efforts involving coupled theory and physical findings, critical experiments still remain the key issue in order to establish more of any basic general concepts. Clearly, the hydrogen/deformation interactions have many facets involving broad service implications. Practical implications: The issue of hydrogen embrittlement or the possible decrease of fracture resistance causing severe mechanical degradation requires special attention. Originality/value: The current investigation includes nano-mechanical probes on top of surface probe microscopy. This technique offered additional critical experiments aimed to resolve the scaling relationship. Moreover, the study assisted to reveal local/global insights related to the interaction conditions involved. One of the values to be mentioned resulted even from the subcritical crack path input. The crack path habits with hydrogen interaction served as critical information. In this context, crack path findings supported the assessment of the possible viable micro-mechanical interactive embrittlement models. Basically, the crack path and the crack-tip front varied with the different crack systems. The important role of plasticity in the cleavage mode formation has been substantiated. Alluded to the above implies that critical experiments might eventually provide the building blocks for modeling efforts that can truly simulate and anticipate embrittlement events. It is demonstrated that huge gaps in knowledge exist preventing appropriate bridging of scales. This has often led to controversy when addressing multiple affected microstructures. This multiplicity occurs due to numerous second phases and interfaces that can interact in various modes with aggressive environment affecting both localized flow and fracture. Only by breaking the microstructure down to its individual building blocks can the scale bridging be appropriately dealt with.

17

Dynamic changes in the tubulin cytoskeleton during oogenesis and early development in the anuran amphibian Xenopus laevis [Daudin]

51%

Palecek J. , Ubbels G. A.

Folia Histochemica et Cytobiologica

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1997

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tom 35

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nr 1

18

Cleavage in Ixodes ricinus [L.] [Acari: Ixodidae]

51%

Jasik K.

Wiadomości Parazytologiczne

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2006

|

tom 52

|

nr 4

EN

The author analyzed the first 5 days of embryonic development of Ixodes ricinus. The cleavage takes 4 days, being terminated on the 5th day of embryogenesis, when the cells start to invaginate and differentiate. The karyomeres play a role in the initial mitotic divisions. Cellularization occurs on the 2nd and 3rd day of embryogenesis. The blastoderm cells maintain their potential for division, and as from the 5th day cellular differentiation starts.

19

Use of IHF - mediated Achilles' heel cleavage [IHF-AC] method for mapping ihf sites

51%

Kur J.

Acta Microbiologica Polonica

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1993

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tom 42

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nr 2

20

Rana esculenta developmental syndrome: fates of abnormal embryos from the first cleavage until spontaneous death

51%

Ogielska M.

Zoologica Poloniae

|

1994

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tom 39

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nr 3-4