ВЛИЯНИЕ ВОДЫ НА ФАНЕРУ, ОБЛИЦОВАННУЮ С ДВУХ СТОРОН ДРЕВЕСНЫМИ СРЕЗАМИ

Maximum use of raw materials that are classified as waste products in order to guarantee rational use of nature resources is one of the key problems in Ukraine nowadays. Low-grade wood branches are applied in the production of boards' alternatives to chipboards. As wood is porous, it is influenced by different types of moisture. Consequently the aim of study is to determine the degree of moisture effects on plywood coated with wooden slices of different species. The authors choose PVAC adhesive class D3. Birch veneer was used to form the three-layer plywood or five-layer plywood as the bases for wood composite, which was coated on both sides with wood slices of birch (Betula pendula), walnut (Juglans regia) and lime (Tilia europaea). We tested materials on water absorption and swelling in thickness. They are as follows: three-layer plywood faced by walnut wood slices impregnated with glue (Wal Im 3), non-impregnated (Wal Non-Im 3), impregnated birch wood slices (Bir Im 3); five-layer plywood faced by birch wood slices impregnated with glue (Bir Im 5), lime wood slices impregnated with glue (Lin Im 5). The highest degree of water absorption and swelling in thickness was observed in plywood, which was coated with non-impregnated walnut slices. This is due to the presence of voids between the wood cells. Impregnated birch and walnut chips have shown the best results. To conclude, we have determined the degree of water absorption and swelling in thickness of plywood, coated with wood slice of birch, walnut and lime. We have also identified that pre-impregnated of wood chips with glue reduces the effect of liquid water on this wood composite.Наведено результати з визначення водопоглинання та набрякання (або розбухання) три- та п'ятишарової фанери, виготовленої зі шпону берези (Betula), личкованої з обох боків деревними зрізами (чіпсами) берези (Betula pendula), горіха (Juglans regia) та липи (Tilia europaea). Для склеювання фанери та просочування зрізів використано полівінілацетатну дисперсію (далі ПВА) зі ступенем водостійкості Д3. Подано графіки з порівнянням водопоглинання та набрякання фанери, облицьованої зрізами різних порід. Визначено, що фанера з деревними зрізами берези поглинає менше води порівняно зі зрізами інших досліджуваних порід.Приведены результаты по определению водопоглощения и набухания трех- и пятислойной фанеры, изготовленной из шпона березы (Betula), облицованной с обеих сторон деревянными срезами (чипсами) березы (Betula pendula), ореха (Juglans regia) и липы (Tilia europaea). Для склеивания фанеры и пропитки срезов использована поливинилацетатная дисперсия (далее ПВА) со степенью водостойкости Д3. Представлены графики со сравнением водопоглощения и набухания фанеры, облицованной срезами различных пород. Установлено, что фанера с древесными срезами березы поглощает меньше воды по сравнению со срезами других исследованных пород

Induction and repair of DNA double-strand breaks in hippocampal neurons of miсe of different age after exposure to

One of the central problems of modern radiobiology is the study of DNA damage induction and repair mechanisms in central nervous system cells, in particular, in hippocampal cells. The study of the regularities of molecular damage formation and repair in the hippocampus cells is of special interest, because these cells, unlike most cells of the central nervous system (CNS), keep proliferative activity, i.e. ability to neurogenesis. Age-related changes in hippocampus play an important role, which could lead to radiosensitivity changes in neurons to the ionizing radiation exposure. Regularities in DNA double-strand breaks (DSB) induction and repair in different aged mice hippocampal cells in vivo and in vitro under the action of γ-rays 60Со were studied with DNA comet-assay. The obtained dose dependences of DNA DSB induction are linear both in vivo and in vitro. It is established that in young animals' cells, the degree of DNA damage is higher than in older animals. It is shown that repair kinetics is basically different for exposure in vivo and in vitro

Induction and repair of DNA double-strand breaks in hippocampal neurons of miсe of different age after exposure to 60Со γ-rays in vivo and in vitro

One of the central problems of modern radiobiology is the study of DNA damage induction and repair mechanisms in central nervous system cells, in particular, in hippocampal cells. The study of the regularities of molecular damage formation and repair in the hippocampus cells is of special interest, because these cells, unlike most cells of the central nervous system (CNS), keep proliferative activity, i.e. ability to neurogenesis. Age-related changes in hippocampus play an important role, which could lead to radiosensitivity changes in neurons to the ionizing radiation exposure. Regularities in DNA double-strand breaks (DSB) induction and repair in different aged mice hippocampal cells in vivo and in vitro under the action of γ-rays 60Со were studied with DNA comet-assay. The obtained dose dependences of DNA DSB induction are linear both in vivo and in vitro. It is established that in young animals' cells, the degree of DNA damage is higher than in older animals. It is shown that repair kinetics is basically different for exposure in vivo and in vitro

Radiobiological Effects of the Combined Action of 1-β-D-Arabinofuranosylcytosine and Proton Radiation on B16 Melanoma in vivo

Abstract Taking into account the previously obtained data on the ability of 1-β-D-arabinofuranosylcytosine (AraC) to significantly increase the number of DNA double-strand breaks after cell culture exposure to ionizing radiation in vitro, the aim of this study was to evaluate the combined action of this compound and proton radiation at a focal dose of 10 Gy on of B16 melanoma growth and a number of processes associated with the radiation response of the tumor—in comparison with those after single irradiation with a proton beam in vivo. Significant tumor growth inhibition was established in both groups of irradiated animals in comparison with the control; the most pronounced effect was observed with combined exposure. Molecular cell parameters of cell death and proliferative activity changed approximately to the same extent after the studied exposures compared with the control. However, the proportion of cancer stem cells was reduced by 3.1 times after combined exposure compared with single irradiation (p = 0.003), which, at least in part, explains the greatest inhibition of tumor growth after irradiation in the presence of AraC