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Wyszukujesz frazę "low doses" wg kryterium: Wszystkie pola


Tytuł:
Damage Assessment in Low Doses $\text{}^{30}Si^{+}$-Implanted GaAs
Autorzy:
Desnica Franković, D.
Desnica, V.
Furić, K.
Powiązania:
https://bibliotekanauki.pl/articles/1807802.pdf
Data publikacji:
2009-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.30.Ly
61.72.Vv
63.50.+x
Opis:
Ion implantation is a widely used technique in device technology, and becoming even more important as the size of devices decreases. The studies of damage and introduced defects have been extensive and, although the overall development and annealing of the implantation damage is relatively well understood, many details remain unclear. Especially, not enough attention has been paid to the effects of very low doses, which are particularly important in controlling the threshold voltage of transistors in the fabrication of GaAs integrated circuits. The reason might be that the induced changes were very often below the detectivity limits of standard methods. In this work, we present the disorder analysis, conducted on GaAs implanted with low ion doses. Czochralski grown, undoped, (100) oriented GaAs samples were implanted with 100 keV $\text{}^{30}Si^{+}$ ions, doses ranging from 3×$10^{11}//cm^{2}$-3×$10^{13}//cm^{2}$, at 21°C. The damage assessment was done by applying Raman scattering and Rutherford backscattering ion channeling (RBS), linked by the inter-cascade distance model and the results were then compared with the results of photoacoustic displacement technique. We have shown that Raman scattering is very sensitive method even if applied on samples implanted with very low doses. Furthermore, the equivalency between the Raman scattering and Rutherford backscattering damage assessment, previously established for high doses via the inter-cascade distance model, proved equally valid also for very low implantation doses, where implanted ions create disordered cascades that are far apart, and most of the layer is still undamaged.
Źródło:
Acta Physica Polonica A; 2009, 116, 1; 42-46
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of ionizing radiation low doses on early stages of odontogenesis
Autorzy:
Cheshko, N. N.
Berlov, H. A.
Pohodenko-Chudakova, I. O.
Powiązania:
https://bibliotekanauki.pl/articles/285617.pdf
Data publikacji:
2008
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Polskie Towarzystwo Biominerałów
Tematy:
odontogenesis
ionizing radiation low doses
tooth germ
Źródło:
Engineering of Biomaterials; 2008, 11, no. 77-80; 7-8
1429-7248
Pojawia się w:
Engineering of Biomaterials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental assessment of ionizing radiation low doses impact on teeth development
Autorzy:
Cheshko, N. N.
Berlov, H. A.
Pohodenko-Chudakova, I. O.
Powiązania:
https://bibliotekanauki.pl/articles/285397.pdf
Data publikacji:
2009
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Polskie Towarzystwo Biominerałów
Tematy:
ionizing radiation
teeth development
laboratory experiment
Źródło:
Engineering of Biomaterials; 2009, 12, no. 89-91; 8-9
1429-7248
Pojawia się w:
Engineering of Biomaterials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The cancer risk among workers of the nuclear centre at Świerk, Poland
Autorzy:
Fornalski, K.W.
Dobrzyński, L.
Powiązania:
https://bibliotekanauki.pl/articles/148146.pdf
Data publikacji:
2013
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
nuclear workers
low doses
radiation influence
Świerk
Polska
Opis:
Dosimetric information concerning 4606 workers at the nuclear centre at Świerk (Poland) from 1956 to 2001 and medical records of 575 workers are reviewed. The average cumulative doses per person were 34 mSv (effective dose) and 18 mSv (equivalent dose to hands). The calculated odds ratio of cancers, OR = 0.90 (0.62–1.18; 68% CI), shows a statistically insignificant decrease of the cancer risk among the irradiated workers. No cancer cases were detected neither among 52 people exposed to the highest cumulative doses (from 35 to 653 mSv) nor among 43 workers who had been chronically irradiated for a long time (from 13 to 26 years).
Źródło:
Nukleonika; 2013, 58, 4; 537-542
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of low doses of gamma rays on the stability of normal and diabetic erythrocytes
Autorzy:
Kaczmarska, Magdalena
Kopyściańska, Zofia
Fornal, Maria
Grodzicki, Tomasz
Matlak, Krzysztof
Korecki, Józef
Burda, Květoslava
Powiązania:
https://bibliotekanauki.pl/articles/1039830.pdf
Data publikacji:
2011
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
γ rays
diabetes
absorption spectroscopy
Mössbauer spectroscopy
hemoglobin
erythrocytes
hemolysis
Opis:
We studied the influence of low doses of γ radiation (from 0.04 to 1.8 mGy) on the stability of human red blood cells (RBC) from healthy donors and diabetic patients using absorption spectroscopy. Because of the alteration of many enzymatic pathways in diabetic RBCs resulting in strong modification of the lipid and protein membrane components one could expect that the ionizing γ-radiation should influence the stability of the healthy and diabetic cells in a different way. Indeed, distinct discontinuities and monotonic changes of hemolysis detected in the healthy and diabetic RBCs suggest that various enzymatic and chemical processes are activated in these membranes by γ radiation. Mössbauer measurements showed that only the highest applied dose of γ radiation caused modification of hemoglobin in both types of RBCs.
Źródło:
Acta Biochimica Polonica; 2011, 58, 4; 489-496
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nuclear magnetic resonance spectroscopy reveals metabolic changes in living cardiomyocytes after low doses of ionizing radiation
Autorzy:
Gramatyka, Michalina
Skorupa, Agnieszka
Sokół, Maria
Powiązania:
https://bibliotekanauki.pl/articles/1038408.pdf
Data publikacji:
2018
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
ionizing radiation
metabolomics
HR MAS NMR
cardiotoxicity
Opis:
Several lines of evidence indicate that exposure of heart to ionizing radiation increases the risk of cardiotoxicity manifested by heart dysfunction and cardiovascular diseases. It was initially believed that the heart is an organ relatively resistant to radiation. Currently, however, it is suspected that even low doses of radiation (< 2 Gy) may have a negative impact on the cardiovascular system. Cardiotoxicity of ionizing radiation is associated with metabolic changes observed in cardiac cells injured by radiation. In this study, we used human cardiomyocytes as a model system, and studied their metabolic response to radiation using high-resolution magic angle spinning nuclear magnetic resonance techniques (HR-MAS NMR). Human cardiomyocytes cultured in vitro were exposed to ionizing radiation and their survival was assessed by clonogenic assay. Changes in apoptosis intensity and cell cycle distribution after the irradiation were measured as well. NMR spectra of cardiomyocytes were acquired using Bruker Avance 400 MHz spectrometer at a spinning rate of 3200 Hz. Survival of cardiomyocytes after NMR experiments was assessed by the Trypan blue exclusion assay. Exposure of cardiomyocytes to small doses of ionizing radiation had no effect on cell proliferation potential and intensity of cell death. However, analysis of metabolic profiles revealed changes in lipids, threonine, glycine, glycerophosphocholine, choline, valine, isoleucine, glutamate, reduced glutathione and taurine metabolism. The results of this study showed that ionizing radiation affects metabolic profiles of cardiomyocytes even at low doses, which potentially have no effect on cell viability.
Źródło:
Acta Biochimica Polonica; 2018, 65, 2; 309-318
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stimulatory effects of single low-level irradiations with X-rays on functions of murine peritoneal macrophages
Autorzy:
Cheda, A.
Wrembel-Wargocka, J.
Nowosielska, E.
Janiak, M.
Powiązania:
https://bibliotekanauki.pl/articles/147798.pdf
Data publikacji:
2005
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
low doses
X-rays
macrophages
nitric oxide
cytotoxicity
TNF-alfa
Opis:
A number of epidemiological and experimental data indicate that exposures to low doses of low-LET ionising radiation may trigger the activity of natural anti-tumour immune mechanisms and inhibit tumour growth. In the present study, we assessed the cytotoxic activity and production of nitric oxide, superoxide anions, and tumour necrosis factor-alfa in peritoneal macrophages collected from BALB/c mice exposed to single whole-body irradiations with 0.1, 0.2, or 1.0 Gy X-rays. The results indicate that all the tested parameters were significantly up-regulated in macrophages obtained from mice exposed to 0.1 or 0.2 Gy X-rays but not in those collected from the sham-irradiated and 1.0 Gy-exposed animals.
Źródło:
Nukleonika; 2005, 50,suppl.2; 13-16
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Low doses of fenofibrate and bezafibrate stimulate renal 2-oxoglutarate dehydrogenase (2-OGDH) in protein-restricted rats
Autorzy:
Knapik-Czajka, Malgorzata E.
Drag, Jagoda M.
Gawedzka, Anna
Powiązania:
https://bibliotekanauki.pl/articles/895613.pdf
Data publikacji:
2020-04-29
Wydawca:
Polskie Towarzystwo Farmaceutyczne
Tematy:
2-oxoglutarate dehydrogenase
Fenofibrate
Bezafibrate
kidney
Opis:
2-oxoglutarate dehydrogenase (2-OGDH) is the key regulatory enzyme of cell metabolism. It has been previously demonstrated that in rats subjected to protein restriction low, clinically relevant doses of fibrates up-regulate liver 2-OGDH and promote 2-oxoglutarate catabolism. The aim of the present study was to evaluate the effect of low doses of fenofibrate and bezafibrate on renal 2-OGDH complex in rats fed low-protein chow. Fibrates were administrated for 14 days to Wistar male rats at one daily doses of 5, 10 and 20 mg/kg b.wt./day. The 2-OGDH activity was assayed spectrophotometrically. The mRNA levels for 2-OGDH catalytic subunits (E1 and E2) and PPARα were quantified by means of semi-quantitative reverse-transcription-PCR. 2-OGDH activity increased in response to administration of fenofibrate and bezafibrate (by 11, 24, 32% and 9, 12, 21%, respectively). The difference was statistically significant for the doses of 10 and 20 mg/kg b.wt of fenofibrate (p<0.001) and the highest dose of bezafibrate (p<0.05). Stimulation of 2-OGDH was not accompanied by changes in mRNA levels for E1 and E2. In addition, mRNA level for PPARα did not change. It is conceivable that fibrate-induced stimulation of 2-OGDH activity can affect renal metabolism and contribute to changes in kidney functions.
Źródło:
Acta Poloniae Pharmaceutica - Drug Research; 2020, 77, 2; 281-288
0001-6837
2353-5288
Pojawia się w:
Acta Poloniae Pharmaceutica - Drug Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Measurements of doses from photon beam irradiation and scattered neutrons in an anthropomorphic phantom model of prostate cancer: a comparison between 3DCRT, IMRT and tomotherapy
Autorzy:
Kowalik, A.
Jackowiak, W.
Malicki, J.
Skórska, M.
Adamczyk, M.
Konstanty, E.
Piotrowski, T.
Polaczek-Grelik, K.
Powiązania:
https://bibliotekanauki.pl/articles/146348.pdf
Data publikacji:
2017
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
3DCRT
IMRT
low doses
neutron doses
thermoluminescent detectors (TLD)
tomotherapy
Opis:
The rapid development of new radiotherapy technologies, such as intensity modulated radiotherapy (IMRT) or tomotherapy, has resulted in the capacity to deliver a more homogenous dose in the target. However, the higher doses associated with these techniques are a reason for concern because they may increase the dose outside the target. In the present study, we compared 3DCRT, IMRT and tomotherapy to assess the doses to organs at risk (OARs) resulting from photon beam irradiation and scattered neutrons. Material and methods. The doses to OARs outside the target were measured in an anthropomorphic Alderson phantom using thermoluminescence detectors (TLD 100) 6Li (7.5%) and 7Li (92.5%). The neutron fluence rate [cm–2·s–1] at chosen points inside the phantom was measured with gold foils (0.5 cm diameter, mean surface density of 0.108 g/cm3). Results. The doses [Gy] delivered to the OARs for 3DCRT, IMRT and tomotherapy respectively, were as follows: thyroid gland (0.62 ± 0.001 vs. 2.88 ± 0.004 vs. 0.58 ± 0.003); lung (0.99 ± 0.003 vs. 4.78 ± 0.006 vs. 0.67 ± 0.003); bladder (80.61 ± 0.054 vs. 53.75 ± 0.070 vs. 34.71 ± 0.059); and testes (4.38 ± 0.017 vs. 6.48 ± 0.013 vs. 4.39 ± 0.020). The neutron dose from 20 MV X-ray beam accounted for 0.5% of the therapeutic dose prescribed in the PTV. The further from the field edge the higher the contribution of this secondary radiation dose (from 8% to ~45%). Conclusion. For tomotherapy, all OARs outside the therapeutic field are well-spared. In contrast, IMRT achieved better sparing than 3DCRT only in the bladder. The photoneutron dose from the use of high-energy X-ray beam constituted a notable portion (0.5%) of the therapeutic dose prescribed to the PTV.
Źródło:
Nukleonika; 2017, 62, 1; 29-35
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effects of experimental administration of low doses of zearalenone on the histology of ovaries in pre-pubertal bitches
Autorzy:
Gajęcka, M.
Powiązania:
https://bibliotekanauki.pl/articles/2087998.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Opis:
The experiment involved 30 clinically healthy Beagle bitches aged approximately 70 days with an initial body weight of approximately 8 kg. The animals were randomly divided into two experimental groups (EI and EII) and a control group of 10 animals each. Group EI was administered 50 μg of body weight zearalenone/kg per os for 42 days, group EII received 75 μg of body weight zearalenone/kg per os for 42 days, and the control group was administered placebo per os for 42 days. The bitches were ovariectomized at the end of the treatment period for anatomopathological examination. At the same time, peripheral blood samples were collected for endocrinological analyses (17β-estradiol and progesterone). Administartion of zearalenone particularly higher doses, resulted in the hyperestrogenism degeneration and atrophy of ovarian cells and tissues with accompanying edema and blood extravasation, leading to increased 17β-estradiol concentrations and an insignificant decrease in progesterone levels.
Źródło:
Polish Journal of Veterinary Sciences; 2013, 16, 2
1505-1773
Pojawia się w:
Polish Journal of Veterinary Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł

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