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Tytuł:
Histone H2AX in DNA repair
Autorzy:
Lewandowska, H.
Szumiel, I.
Powiązania:
https://bibliotekanauki.pl/articles/147030.pdf
Data publikacji:
2002
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
DNA double strand breaks
DNA repair
histone gamma-H2AX
ionising radiation
Opis:
The paper reviews the recent reports on the role of the phosphorylated histone H2AX (gamma-H2AX). The modification of this histone is an important part of the cellular response to the induction of DNA double strand breaks (DSB) by ionising radiation and other DSB-generating factors. In irradiated cell the modification is carried out mainly by ATM (ataxia- -telangiectasia mutated) kinase, the enzyme that starts the alarm signalling upon induction of DSB. gamma-H2AX molecules are formed within 1 3 min after irradiation and form foci at the sites of DSB. This seems to be necessary for the recruitment of repair factors that are later present in foci of damaged nuclei. Modification of a constant percentage of H2AX molecules per DSB takes place, corresponding to chromatin domains of megabase pairs of DNA.
Źródło:
Nukleonika; 2002, 47, 4; 127-131
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modified neutral comet assay for human lymphocytes
Autorzy:
Wojewódzka, M.
Grądzka, I.
Buraczewska, I.
Powiązania:
https://bibliotekanauki.pl/articles/147130.pdf
Data publikacji:
2002
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
DNA double strand breaks
human lymphocyte
neutral comet assay
Opis:
Comet assay under neutral conditions allows the detection of DNA double-strand breaks, considered to be the biologically relevant radiation-induced lesion. In this report we describe modifications of the neutral comet method, which simplify and facilitate its use for estimation of DNA double strand breaks in human lymphocytes irradiated with doses of 60Co gamma-rays (from 10 to 100 Gy). The analysis carried out according to this protocol takes less time than those published so far. Also, the use of lysis at 50°C is avoided; this is important in view of the presence of heat-labile sites in the DNA of irradiated cells, recently reported by Rydberg [12]. The comets have well defined, sharp limits, are suitable for computer image analysis and chromatin of the control cells remains condensed.
Źródło:
Nukleonika; 2002, 47, 1; 1-5
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Non-homologous DNA end joining.
Autorzy:
Pastwa, Elżbieta
Błasiak, Janusz
Powiązania:
https://bibliotekanauki.pl/articles/1043360.pdf
Data publikacji:
2003
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
Ku proteins
DNA-PK
homologous recombination
non-homologous end joining
DSB; DNA repair
DNA ligase IV
DNA double-strand breaks
NHEJ
Opis:
DNA double-strand breaks (DSBs) are a serious threat for the cell and when not repaired or misrepaired can result in mutations or chromosome rearrangements and eventually in cell death. Therefore, cells have evolved a number of pathways to deal with DSB including homologous recombination (HR), single-strand annealing (SSA) and non-homologous end joining (NHEJ). In mammals DSBs are primarily repaired by NHEJ and HR, while HR repair dominates in yeast, but this depends also on the phase of the cell cycle. NHEJ functions in all kinds of cells, from bacteria to man, and depends on the structure of DSB termini. In this process two DNA ends are joined directly, usually with no sequence homology, although in the case of same polarity of the single stranded overhangs in DSBs, regions of microhomology are utilized. The usage of microhomology is common in DNA end-joining of physiological DSBs, such as at the coding ends in V(D)J (variable(diversity) joining) recombination. The main components of the NHEJ system in eukaryotes are the catalytic subunit of DNA protein kinase (DNA-PKcs), which is recruited by DNA Ku protein, a heterodimer of Ku70 and Ku80, as well as XRCC4 protein and DNA ligase IV. A complex of Rad50/Mre11/Xrs2, a family of Sir proteins and probably other yet unidentified proteins can be also involved in this process. NHEJ and HR may play overlapping roles in the repair of DSBs produced in the S phase of the cell cycle or at replication forks. Aside from DNA repair, NHEJ may play a role in many different processes, including the maintenance of telomeres and integration of HIV-1 genome into a host genome, as well as the insertion of pseudogenes and repetitive sequences into the genome of mammalian cells. Inhibition of NHEJ can be exploited in cancer therapy in radio-sensitizing cancer cells. Identification of all key players and fundamental mechanisms underlying NHEJ still requires further research.
Źródło:
Acta Biochimica Polonica; 2003, 50, 4; 891-908
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Concerted control of DNA double strand break repair and cell cycle progression in X-irradiated mammalian cells
Autorzy:
Sochanowicz, B.
Szumiel, I.
Powiązania:
https://bibliotekanauki.pl/articles/148697.pdf
Data publikacji:
2005
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
ATM kinase
DNA double strand break repair
RAD50
cell cycle arrest
repair foci
BRCT domain
Opis:
Upon examination of cell cycle regulation in a damaged cell, relations were discovered of the cell cycle control mechanisms with a complicated web of signalling pathways, eventually called the genome surveillance system. After infliction of DNA double strand breaks (DSB), the signalling is initiated by sensor proteins and transducer protein kinase ATM. This kinase phosphorylates downstream effector proteins, such as checkpoint kinases CHK1 and CHK2, which initiate the pathways leading to cell cycle arrest. In contrast with the older model of linear transmission of signals in a certain sequence, it is now accepted that the damage signalling system is branched and contains feedback loops. DSB's presence is signalled by sensor proteins (MRE11-RAD50-nibrin complex, MRN) to ATM and the signal is amplified through adaptor proteins, MDC1/NFBD1 or 53BP1 (Tp53 binding protein). MRN contains a forkheadassociated (FHA) domain and BRCA1 carboxyl-terminal (BRCT) domain. The combination of the FHA/BRCT domains has a crucial role for the binding of nibrin to the H2AX histone, assembling the components of repair foci. These domains also are important for interaction of other proteins localised in the foci. For example, MDC1/NFBD1 contains a FHA domain and two BRCT domains which are involved in protein interactions. The signal generated at DSBs is amplified and transduced to recruit components of DNA repair systems. In a concerted way with the sequential recruitment of components of repair foci, activation of transcription of genes takes place, that is necessary for blocking progression through the cell cycle, for DNA repair or apoptosis.
Źródło:
Nukleonika; 2005, 50, 4; 129-138
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
DNA double-strand break rejoining in radioadapted human lymphocytes: evaluation by neutral comet assay and pulse-field gel electrophoresis
Autorzy:
Wojewódzka, M.
Buraczewska, I.
Szumiel, I.
Grądzka, I.
Powiązania:
https://bibliotekanauki.pl/articles/146153.pdf
Data publikacji:
2006
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
human lymphocytes
radioadaptation
DNA double-strand break rejoining
neutral comet assay
pulsefield gel electrophoresis
Opis:
Adaptive response (AR), an enhanced resistance to a high dose of ionising radiation acquired after pretreatment with a very low dose, was estimated in normal human lymphocytes. The question posed was whether the extent of radioadaptation, assessed by micronucleus test, would be related to the rate of DNA double-strand break (DSB) rejoining. Phytohemagglutinin-stimulated G1-lymphocytes from 5 healthy male volunteers were pre-treated (or not) with an adaptive (5 cGy) dose of X-rays, followed by a higher (5 or 10 Gy) challenge dose after 20-22 h. DSB rejoining after the challenge dose was monitored with the use of two methods: neutral comet assay, modified to reduce the contribution of single-strand breaks (SSBs) and thermolabile sites, and pulse-field gel electrophoresis (PFGE), specific for DSBs. At the level of micronuclei, an AR was observed in lymphocytes of 3 of 5 donors. Up to 60 min, comet assay showed no statistically significant differences in DNA break rejoining between adapted and non-adapted lymphocytes, independently of AR appearance. PFGE gave similar results, although in three donors it revealed secondary increases in DSBs levels at 30 min and/or 60 min post-irradiation in the adapted vs. the non-adapted samples. Failure to demonstrate changes in DSBs rejoining rate in the adapted lymphocytes could be due to diversity of AR intensity/timing at the level of DNA repair in not fully homogenous cell populations. Also, “rare” DNA cuts characteristic of early apoptosis/necrosis could overlap the process of DNA break rejoining.
Źródło:
Nukleonika; 2006, 51, 4; 185-191
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nonhomologous end-joining deficiency of L5178Y-S cells is not associated with mutation in the ABCDE autophosphorylation cluster
Autorzy:
Brzóska, Kamil
Kruszewski, Marcin
Szumiel, Irena
Powiązania:
https://bibliotekanauki.pl/articles/1041297.pdf
Data publikacji:
2006
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
mouse lymphoma L5178Y
nonhomologous end-joining
autophosphorylation
DNA-dependent protein kinase
double strand break repair
Opis:
Cells with mutated autophosphorylation sites in the ABCDE cluster of DNA-dependent protein kinase catalytic subunit (DNA-PKcs) are defective in the repair of ionising radiation-induced DSB, but show in an in vitro test the same DNA-PK activity as the cells possessing wild type enzyme. Nevertheless, the mutated DNA-PK is able to undergo ATP-dependent autophosphorylation and inactivation. This characteristics correspond well with the phenotypic features of the L5178Y-S (LY-S) cell line that is defective in DSB repair, shows a pronounced G1 phase radiosensitivity, but in which the level of DNA-PK activity present in total cell extracts is similar to that of its radioresistant counterpart L5178Y-R (LY-R) cell line. The purpose of this work was to examine the possible alterations in the sequence encoding the cluster of autophosphorylation sites in the DNA-dependent protein kinase in LY-S cells. Despite the presence of phenotypic features indicating the possibility of such alterations, no differences were found between the sequences coding for the autophosphorylation sites in L5178Y-R and L5178Y-S cells. In conclusion, the repair defect in LY-S cells is not related to the structure of the DNA-PK autophosphorylation sites (ABCDE casette).
Źródło:
Acta Biochimica Polonica; 2006, 53, 1; 233-236
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Intranuclear trafficking of plasmid DNA is mediated by nuclear polymeric proteins lamins and actin
Autorzy:
Ondřej, Vladan
Lukášová, Emilie
Krejčí, Jana
Kozubek, Stanislav
Powiązania:
https://bibliotekanauki.pl/articles/1040744.pdf
Data publikacji:
2008
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
plasmid DNA
DNA double-strand breaks
nuclear actin
lamin A/C
Opis:
Functions of nuclear polymeric proteins such as lamin A/C and actin in transport of plasmid DNA were studied. The results show that the lamina plays an important role in plasmid DNA's entry into the cell nucleus from the cytoplasm. Selective disruption of lamin A/C led to a halt in plasmid DNA transport through the nuclear envelope. Inside the nucleus, plasmid DNA was frequently localized at sites with impaired genome integrity, such as DNA double-strand breaks (DSBs), occurring spontaneously or induced by ionizing radiation. Polymeric actin obviously participates in nuclear transport of plasmid DNA, since inhibition of actin polymerization by latrunculin B disturbed plasmid transport inside the cell nucleus. In addition, precluding of actin polymerization inhibited plasmid co-localization with newly induced DSBs. These findings indicate the crucial role of polymeric actin in intranuclear plasmid transport.
Źródło:
Acta Biochimica Polonica; 2008, 55, 2; 307-315
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Relationships between EGFR-initiated signalling, DNA double-strand break rejoining and survival in X-irradiated human glioma M059 cells
Autorzy:
Grądzka, I.
Buraczewska, I.
Szumiel, I.
Powiązania:
https://bibliotekanauki.pl/articles/146764.pdf
Data publikacji:
2008
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
human glioma M059 K and J cells
DNA-dependent protein kinase (DNA-PK)
radiosensitivity
DNA double-strand break (DSB) rejoining
epidermal-growth-factor-receptor (EGFR)
signalling inhibitors: tyrphostin
Opis:
The aim of this study was to investigate the effect of signalling inhibition on survival and double-strand break (DSB) rejoining in cells differing in sensitivity to inhibitors, X-rays and bleomycin. Human glioma M059 cells, K (relatively radioresistant) and J (radiosensitive, defective in DSB rejoining for lack of DNA-dependent protein kinase catalytic subunit, DNA-PKcs) were pretreated with signalling inhibitors: tyrphostin AG 1478, specific for epidermalgrowth- factor-receptor (EGFR) kinase or PD 98059, specific for kinase MEK 1/2 (mitogen-activated, extracellular signal-activated kinases 1 and 2). Subsequently, the cells were X-irradiated or treated with bleomycin. Cell survival was determined by clonogenicity test. DSB rejoining was monitored with the use of pulsed-field gel electrophoresis (PFGE). We found that in X-irradiated M059 K cells EGFR kinase activity was necessary for efficient DSB rejoining and the kinase inhibitor, tyrphostin AG 1478, acted as radiosensitizer in the dose range that reduced cell survival to 0.7-0.8. Inhibition of EGFR kinase, however, did not decrease survival or affect DSB rejoining in DNA-PKcs-deficient M059 J cells. These results indicated that the decrease in cell survival was due to a disturbed DSB rejoining by the DNA-PK dependent system. In contrast, inhibition of MEK 1/2 kinase on EGFR downstream signalling pathway by PD 98059 did not affect DSB rejoining in either cell line and exerted a radioprotective effect.
Źródło:
Nukleonika; 2008, 53, 2; 37-44
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Inhibition of poly(ADP-ribose) polymerase activity affects its subcellular localization and DNA strand break rejoining
Autorzy:
Ryabokon, Nadezhda
Cieślar-Pobuda, Artur
Rzeszowska-Wolny, Joanna
Powiązania:
https://bibliotekanauki.pl/articles/1040571.pdf
Data publikacji:
2009
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
DNA strand break rejoining
efficiency of PARP inhibition
PARP foci
poly(ADP-ribose) polymerase (PARP)
PARP inhibitors
Opis:
Poly(ADP-ribose) polymerase (PARP) plays a crucial role in DNA repair. Modulation of its activity by stimulation or inhibition is considered as a potentially important strategy in clinical practice, especially to sensitize tumor cells to chemo- and radiotherapy through inhibition of DNA repair. Here we studied the effect of the three PARP inhibitors, 5-iodo-6-amino-benzopyrone (INH2BP), 1,5-isoquinolinediol (1,5-dihydroxyisoquinolinediol (1,5-IQD) and 8-hydroxy-2-methylquinazolin-4-[3H]one (NU1025), and for two of them the efficiency in slowing the rejoining of DNA strand breaks induced by H2O2 was compared. Inhibition of PARP changed its intranuclear localization markedly; cells exposed to the inhibitor NU1025 showed a significant tendency to accumulate PARP in large foci, whereas in untreated cells its distribution was more uniform. The speed and efficiency of rejoining of H2O2-induced DNA strand breaks were lower in cells incubated with a PARP inhibitor, and the kinetics of rejoining were modulated in a different manner by each inhibitor. At a concentration of 100 µM the efficiency of the inhibitors could be ranked in the order NU1025 > IQD > INH2BP. The two first compounds were able to decrease the overall PARP activity below the level detected in control cells, while INH2BP showed up to 40% PARP activity after exposure to H2O2.
Źródło:
Acta Biochimica Polonica; 2009, 56, 2; 243-248
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Chromatin acetylation, β-amyloid precursor protein and its binding partner FE65 in DNA double strand break repair
Autorzy:
Szumiel, Irena
Foray, Nicolas
Powiązania:
https://bibliotekanauki.pl/articles/1039940.pdf
Data publikacji:
2011
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
chromatin acetylation
FE65
MOF acetyltransferase
DNA double strand break repair
β-amyloid precursor protein
Tip60 histone acetyltransferase
heterochromatin protein 1
Opis:
Among post-translational modifications of chromatin proteins taking place in DNA double strand break (DSB) repair, acetylation plays a prominent role. This review lists several facts and hypotheses concerning this process. Lack of acetyltransferase TIP60 (HIV-Tat interacting protein of 60 kDa) activity results in cells with defective DSB repair. The enzyme is present in the nucleus in a multimeric protein complex. TIP60 dependent activation of ATM (ataxia telangiectasia mutated kinase) is an early event in the response to DNA breakage. Other important acetylations are those of histones H4 and γH2AX. Correct reconstruction of the damaged site is critical for survival and prevention of genetic and epigenetic changes in the cell that may affect the function of its daughter cells. Recently, two proteins with previously unsuspected functions in DSB repair have been identified as active in this process: Alzheimer β-amyloid precursor protein (APP) and its binding partner FE65, β-amyloid precursor binding protein. Their participation in DSB repair in both neuronal and non-neuronal cells is related to acetylation carried out by the acetyltransferase complex. The same function is ascribed to heterochromatin protein 1 (HP1). So far, the relations (if any) between TIP60 activation by HP1 and by the FE65 complex remain unidentified.
Źródło:
Acta Biochimica Polonica; 2011, 58, 1; 11-18
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Low recombination activity of R region located at both ends of the HIV-1 genome
Autorzy:
Urbanowicz, Anna
Kurzyńska-Kokorniak, Anna
Jankowska, Anna
Alejska, Magdalena
Figlerowicz, Marek
Powiązania:
https://bibliotekanauki.pl/articles/1039669.pdf
Data publikacji:
2012
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
copy-choice mechanism
template switching
homologous RNA recombination
strand transfer
R region
RNA virus
retrovirus
Opis:
Although two strand transfer events are indispensable for the synthesis of double-stranded DNA and establishing HIV-1 infection, the molecular basis of these phenomena is still unclear. The first obligatory template switching event occurs just at the beginning of the virus replication cycle and involves two copies of the 97-nucleotide long R region, located one each at the both ends of the HIV-1 genome (HIV-1 R). Thus, one can expect that the molecular mechanism of this process is similar to the mechanism of homologous recombination which operates in RNA viruses. To verify the above-mentioned hypothesis, we attempted to assess the recombination activity of HIV-1 R. To this end, we tested in vitro, how effectively it induces template switching by HIV-1 RT in comparison with another well-characterized sequence supporting frequent homologous crossovers in an unrelated virus (R region derived from Brome mosaic virus - BMV R). We also examined if the RNA sequences neighboring HIV-1 R influence its recombination activity. Finally, we tested if HIV-1 R could cause BMV polymerase complex to switch between RNA templates in vivo. Overall, our results have revealed a relatively low recombination activity of HIV-1 R as compared to BMV R. This observation suggests that different factors modulate the efficiency of the first obligatory strand transfer in HIV-1 and the homology-driven recombination in RNA viruses.
Źródło:
Acta Biochimica Polonica; 2012, 59, 4; 619-626
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Metoda znajdowania komórek i zliczania ognisk występowania histonu γ-H2AX w obrazach na potrzeby detekcji dwuniciowych pęknięć DNA
Method for cell finding and histone γ-H2AX foci counting in images for detecting DNA double-strand breaks
Autorzy:
Wojciechowski, P.
Bal, A.
Powiązania:
https://bibliotekanauki.pl/articles/154831.pdf
Data publikacji:
2012
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
γ-H2AX
dwuniciowe pęknięcia DNA
przetwarzanie obrazów
obrazy biomedyczne
segmentacja wododziałowa
double-strand breaks (DSB)
image processing
biomedical images
watershed segmentation
Opis:
Niniejsza praca opisuje algorytm automatyzujący proces zliczania ognisk histonu γ-H2AX w obrazach mikroskopowych. Ogniska te są miejscami, w których doszło do fosforylacji białka histonu H2AX w pozycji seryny 139 wskutek dwuniciowych pęknięć DNA. Propono-wana metoda działa dwuetapowo. Najpierw w obrazie mikroskopowym selekcjonowane są obiekty uznawane za komórki, a następnie na obszarze tych obiektów poszukiwane są miejsca wyznakowane barwnikiem fluorescencyjnym związanym z przeciwciałem anty-γ-H2AX - miejsca te wskazują na lokalizację ognisk γ-H2AX.
This paper describes an algorithm for automating the process of counting foci of histone γ-H2AX in microscope images. Foci are the places where there occurred H2AX protein phosphorylation on Ser139 site in response to DNA double-strand breaks (DSBs). In a γ-H2AX genotoxic test the number of foci per a single cell is counted. The proposed method works in two stages. The first stage is segmentation of a microscopic image (Fig. 1a) for selecting cell regions. For this purpose fusion of binarization methods is used - for the each pixel the result is obtained by comparison of the results from the Otsu method, the triangle method and the method in which the threshold is equal to the image average brightness. The pixel is classified as an object's pixel when at least two methods give such results. For improving segmentation results a morphological filter is used. The results (Fig. 1b) usually comprise regions representing single cells (Fig. 1c) and a set of agglomerated cells (Fig. 1d). A modified watershed segmentation and region classify method is used for separation of agglomerated cells into regions representing only one cell. The final result (Fig.1e) contains only regions representing single cells. In the second stage for each single cell region the foci (which are marked with a fluorescent indicator joined with anti- γ-H2AX antibody) are found (Fig. 3) with use of watershed segmentation on the pseudogradient image (which is obtained by aggregation of the results of cell image binarization with different thresholds; Fig. 2). The final results in form of foci number as a function of time after irradiation (Fig. 4) are similar to the test results of non-lethal DNA damages founded in the literature (e.g. [5]) - this allows stating that the presented method gives good results.
Źródło:
Pomiary Automatyka Kontrola; 2012, R. 58, nr 4, 4; 387-390
0032-4140
Pojawia się w:
Pomiary Automatyka Kontrola
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study of Self-twist Distribution Functions in Different Convergence Modes
Badanie funkcji rozkładu skrętu przędzy przy różnych konfiguracjach łączenia
Autorzy:
Cui, H.
Yu, C.
Powiązania:
https://bibliotekanauki.pl/articles/232550.pdf
Data publikacji:
2012
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
pasmo
self-twist
tryb konwergencji
funkcja rozkładu skrętu
w fazie
stopniowo
przędza samoskrętna
strand
convergence mode
twist distribution function
in-phase
phased
Opis:
Twist distribution functions of self-twist yarn are examined by calculating the twist distribution functions of two strands from the nip of self-twist rollers to the convergence point in three different convergence modes. Twist distribution curves of three different convergence modes on the half cycle length are presented by the twist distribution functions. The images show that the self-twist yarn with a phase difference has a lower self-twist peak than inphase self-twist yarn. Thus the existence of a phase difference not only causes a decrease in the self-twist but also a decrease in the length of the weak-twist zone. Furthermore, the value of the phase difference is calculated according to the twist functions of two strands. Compared with the conventional result, that by the method in this paper is closer to the actual length of the zero twist zone.
Funkcje rozkładu skrętu dla przędzy samoskrętnej badano w zależności od punktu łączenia. Funkcje rozkładu zostały przedstawione dla trzech różnych wariantów łączenia. W badaniach analizowano zarówno powstanie przesunięć fazowych jak i okresowych wzrostów wartości skrętu. Na podstawie funkcji rozkładu skrętu dwóch strumieni przędzy można określić przesuniecie fazowe. Stwierdzono, że stosowanie metody identyfikacji opisanej w artykule daje lepsze efekty niż stosowanie metod konwencjonalnych.
Źródło:
Fibres & Textiles in Eastern Europe; 2012, 5 (94); 26-29
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Control of the transmission length in the prestressed hollow-core slabs using values of the strand end slip
Kontrola wartości długości zakotwienia cięgien w sprężonych płytach kanałowych przy użyciu wartości poślizgu splotów
Autorzy:
Tur, V
Fic, S.
Powiązania:
https://bibliotekanauki.pl/articles/390877.pdf
Data publikacji:
2013
Wydawca:
Politechnika Lubelska. Wydawnictwo Politechniki Lubelskiej
Tematy:
Hollow-core slabs
transmission length
slippage
strand
płyta kanałowa
długość zakotwienia
poślizg
splot
Opis:
It is shown [1] that even though the production of precast pre-tensioned concrete elements started more than 50 years ago, no one has ever succeeded in determining the real transmission length or in obtaining adequate measures to control it, due to the quality of the production. These arrears are confirmed by the study of existing standards. In general, it is assumed that the measurement of the magnitude of the slippage of strand at the end of hollow core prestressed slab is an indirect method of estimation and control of the value of the transmission length. One should mention that EN1168 and EN13369 that regulate requirements of designing and production of hollow-core slabs are applied as the method of control. Based on a particular bond-slip relation for strands, a nonlinear equation is developed for the transmission length and for the slippage of prestressed strand, taking into account such factors as the concrete strength at transfer, the degree of the initial prestress type and diameter of tendons. These equations have been used for the control of transmission length of the strands calculated by different methods available recently, including a code provision. Then they were compared to measured data, obtained in production control of the hollow-core slabs.
Bazując na szczególnej relacji przyczepność – poślizg dla splotów, opracowano równania nieliniowe dla długości zakotwienia i dla poślizgu sprężonych splotów przy uwzględnieniu czynników: wytrzymałości betonu, efektywności początkowego sprężenia i rozmiaru splotu. Te równania zostały użyte do skontrolowania długości zakotwienia sprężonych splotów obliczonych za pomocą różnych metod dostępnych w ostatnim czasie, uwzględniając zalecenia normowe, które zostały porównane z wynikami pomiarów uzyskanych podczas kontroli procesu produkcyjnego płyt kanałowych.
Źródło:
Budownictwo i Architektura; 2013, 12, 1; 171-178
1899-0665
Pojawia się w:
Budownictwo i Architektura
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Convergence Point of Three-strand Yarn Spinning
Punkt zbieżności przy przędzeniu przędz trójtaśmowych
Autorzy:
Su, X.
Gao, W.
Liu, X.
Xie, C.
Huang, B.
Powiązania:
https://bibliotekanauki.pl/articles/232053.pdf
Data publikacji:
2013
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
three-strand yarn spinning
theoretical model
convergence point
przędzenie przędz trójtaśmowych
model teoretyczny
punkt zbieżności
Opis:
A theoretical model for the three-strand yarn spinning system is obtained by using the analysis method for the two-strand case presented by He et al. and setting a series of virtual intermediate variables. Then the convergence point of the three-strand yarn spinning is obtained by eliminating the intermediate variables.
Opracowano teoretyczny model systemu przędzenia trójtaśmowej przędzy z wykorzystaniem modelu przędzy dwutaśmowej przedstawionego przez He i innych. Wprowadzono serię teoretycznych zmiennych przejściowych, a następnie ustalono punkt zbieżności dla systemu przędzenia przędzy trójtaśmowej przez eliminacje zmiennych pośrednich.
Źródło:
Fibres & Textiles in Eastern Europe; 2013, 3 (99); 48-50
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
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