Influence of selected environmental factors on moisture dynamics of beech wood

Beech is one of the most important tree species in Slovenia. Unfortunately, there is much more beech wood incremented annually than consumed. Thus, it is of great importance to develop new applications for use of beech wood. One of the possible solutions is use of beech in outdoor applications. However, if beech is used outdoor it has to be somehow protected. In the recent period, non-biocidal methods of wood protection such as thermal modification and use of wax emulsions are gaining more and more importance, hence we applied these two methods to beech wood in present research as well. During the research, water exclusion efficacy of wood was determined. Wood was subjected to various abiotic and biotic degradation protocols. The results exhibited that the best water performance was achieved in wax treated thermally modified beech. Water performance of wax treated wood was not affected by abiotic and biotic degradation factors. By contrast, the aging protocols applied considerably reduced water exclusion efficacy of beech and thermally modified beech wood

Influence of selected environmental factors on moisture dynamics of beech wood

Bukovina sodi med najpomembnejše lesne vrste v Sloveniji. Žal uporaba bukovine zelo zaostaja za prirastkom, zato je treba nujno razviti dodatne aplikacije za rabo bukovega lesa. Ena izmed neizkoriščenih priložnosti je tudi raba za manj zahtevne konstrukcije na prostem. V primeru, da uporabljamo bukovino na prostem, moramo les na takšen ali drugačen način zaščititi. V zadnjem obdobju vedno bolj pridobiva na pomenu termična modifikacija in uporaba voskov, zato smo ti dve rešitvi uporabili tudi v tej raziskavi. Tako smo odpornost bukovine na navlaževanje spremljali v laboratorijskih razmerah in terenskih testih. Pred laboratorijskimi poizkusi smo vzorce izpostavili različnim abiotskim in biotskim dejavnikom razkroja ter določili njihov vpliv na navzemanje vode v les. Izkazalo se je, da se je najbolje obnesel termično modificiran les, impregniran s suspenzijo naravnih voskov. Po drugi strani so abiotski in biotski dejavniki razkroja močno poslabšali odpornost proti navlaževanju bukovine in termično modificirane bukovine.Beech is one of the most important tree species in Slovenia. Unfortunately, there is much more beech wood incremented annually than consumed. Thus, it is of great importance to develop new applications for use of beech wood. One of the possible solutions is use of beech in outdoor applications. However, if beech is used outdoor it has to be somehow protected. In the recent period, non-biocidal methods of wood protection such as thermal modification and use of wax emulsions are gaining more and more importance, hence we applied these two methods to beech wood in present research as well. During the research, water exclusion efficacy of wood was determined. Wood was subjected to various abiotic and biotic degradation protocols. The results exhibited that the best water performance was achieved in wax treated thermally modified beech. Water performance of wax treated wood was not affected by abiotic and biotic degradation factors. By contrast, the aging protocols applied considerably reduced water exclusion efficacy of beech and thermally modified beech wood

Upijanje vode toplinski modificirane norveške smreke

Thermal modification of wood has been commercially available for almost twenty years but the complete mechanism of improved durability is still not completely understood. It is known that the temperature and duration of the modification influences the properties of the final products. There are several potential reasons for the increased durability of the modified wood. In recent research in particular, water exclusion efficiency has been identified as one of the key mechanisms. In order to elucidate this presumption, specimens made of Norway spruce heartwood were thermally modified at 6 different temperatures (160 °C, 180 °C, 190 °C, 200 °C, 210 °C and 230 °C) for three hours according to the Silvapro® procedure. Control specimens were left unmodified. Three sets of tests were performed: (a) samples were soaked in water for 4 days and then positioned on load cells and allowed to dry until a constant mass was achieved; (b) short term water uptake was determined with a tensiometer and (c) wood-water interactions were verified using constant gravimetric moisture measurement during outdoor exposure. As expected, the degree of modification was reflected in the moisture content of the wood during testing. Short and medium term water uptakes correlated quite well with the performance of wood in outdoor applications. On the other hand, long term tensiometer measurements were not in line with either short term water uptake or outdoor measurements.Toplinski modificirano drvo dostupno je na tržištu već gotovo dvadeset godina međutim, potpuni mehanizam poboljšane trajnosti drva još uvijek nije sasvim razjašnjen. Poznato je da temperatura i trajanje modifikacije utječu na svojstva konačnog proizvoda. Nekoliko je razloga za povećanje trajnosti toplinski modificiranog drva. U recentnim istraživanjima učinkovito je odstranjenje vode identificirano kao jedan od ključnih mehanizama za poboljšanje trajnosti drva. Kako bi se razjasnila ta pretpostavka, uzorci drva srži norveške smreke toplinski su modificirani pri šest različitih temperatura (160, 180, 190, 200, 210 i 230 °C) tijekom tri sata prema postupku Silvapro®. Kontrolni su uzorci ostali nemodificirani. Provedena su tri ciklusa ispitivanja: a) uzorci su namakani u vodi tijekom četiri dana, zatim su postavljeni na senzor težine da se osuše do konstantne mase; b) kratkoročno upijanje vode određeno je tenziometrom i c) interakcije drva i vode provjeravane su stalnim gravimetrijskim mjerenjem sadržaja vode pri izlaganju uvjetima na otvorenome. Kao što se očekivalo, stupanj modifikacije ogleda se u sadržaju vode u drvu tijekom ispitivanja. Kratkoročno i srednjoročno upijanje vode dobro korelira s ponašanjem drva u vanjskim uvjetima. Nasuprot tome, dugoročna mjerenja tenziometrom nisu bila u skladu s kratkoročnim vezanjem vode ili s mjerenjem pri izlaganju uvjetima na otvorenome

Selected properties of one hundred year old beech wood

Changes of wood due to ageing are elucidated in this respective article. Beach wood degraded by white rot fungi and furniture beetle was examined. The results of the mechanical tests showed considerable decrease that did not influence on the short term water uptake. Natural durability of old beech wood even decreased what lead us to conclusion that special consideration should be given to the use condition

Recommendations for the Use of Erythrocyte Colony Stimulating Factors in Systemic Treatment of Cancer

Rastni dejavniki za eritrocite (eritropoetini) so naravne beljakovine, ki jih večinoma tvorijo ledvice in ki sodelujejo pri uravnavanju tvorbe rdečih krvničk. Pri onkoloških bolnikih je vzrokov za razvoj anemije več. Pri kroničnih boleznih je najpogostejša normocitna in normokromna anemija, ki nastane zaradi slabšega odziva na eritropoetine in zaradi motene vgradnje železa v hemoglobin. Korekcija anemije izboljša kakovost življenja in zmanjša hipoksijo tumorja, s čimer naj bi se, glede na nekatere študije, povečala učinkovitost sistemskega in obsevalnega zdravljenja. Po začetnem navdušenju nad sintetičnimi eritropoetini (EPA), ki so se pokazali učinkoviti pri izboljšanju kakovosti življenja rakavih bolnikov z anemijo, pa je bilo v zadnjih letih objavljenih kar nekaj velikih raziskav, ki so pokazale več neželenih učinkov, predvsem trombemboličnih zapletov, in trend k slabšemu preživetju pri bolnikih na EPA. To je privedlo do močno okrnjenih priporočil za njihovo uporabo. Danes se uporaba EPA za korekcijo anemije priporoča samo pri bolnikih na specifičnem zdravljenju raka, katerega cilj ni ozdravitev. Zdravilo se uvede le ob simptomatski anemiji, odmerek se skrbno titrira do tarčnega Hb 120 g/L, pri večjih vrednostih Hb pa se EPA ne uporabljajo. Uporabo EPA je treba skrbno pretehtati pri bolnikih s tveganjem za razvoj trombemboličnih dogodkov. Za zdaj ne vemo, ali je nakazano slabše preživetje posledica stimulacije rasti tumorskih celic ali več neželenih učinkov, zlasti trombemboličnih zapletov, ob uporabi EPA. Dokončen odgovor na to in tudi podatke o optimalni rabi EPA pri rakavih bolnikih, nam bodo, upajmo, dali izsledki prospektivnih kliničnih raziskav, ki že potekajo.Erythrocyte colony stimulating factors (erythropoietins) are natural proteins, mainly produced by kidneys. They take part in the regulation of red blood cells production. There are many causes for the development of anemia in cancer patientsthe most frequent is anemia of chronic disease, which is normocytic and normochromic and results from a poor response to erythropoietins and invalid hemoglobin iron uptake. According to some studies, anemia correction increases quality of life (QOL) and decreases tumor hypoxia, thereby leading to a more efficient systemic and irradiation therapy. After the initial enthusiasm on synthetic erythropoietins (EPA), which showed to be effective in improving QOL in anemic cancer patients, some big trials published in the last years showed more side effects, especially thrombembolic complications and a trend towards a worse survival in patients on EPA. This led to strongly curtailed recommendations for their use. Today the use of EPA for anemia correction is recommended only for cancer patients on specific cancer treatment without curative intent. The drug is initiated only with symptomatic anemia, with careful titration of dose to a target Hb of 120 g/L, EPA should not be used with higher Hb values. A thoughtful consideration should be given to the use of EPA in the patients with a risk of thrombembolic events. We still do not know if slightly worse survivals are the consequence of tumor cell growth stimulation or of more side effects, especially thrombembolic complications with EPA usage. The final answer and also data on the optimal use of EPA in cancer patients will be provided, hopefully, by the results of ongoing prospective clinical trials

Service Life of Beech Wood in Outdoor Applications

Beech wood is amongst the most important wood species in Slovenia. The EU standard EN 350-2 classifies beech wood into the group of the least durable wood species. This is one of the most important reasons which limit the use of beech wood in outdoor applications. The majority of the data about beech wood durability is a result of laboratory tests as there were limited numbers of field tests performed. As the service life of wood significantly depends on the local climate conditions, this data cannot be simply copied from other countries. Therefore, field tests have been running at the field test site of the Department of Wood Science and Technology for several years now to determine comprehensive performance of most important Slovenian wood species including beech wood. Majority of the tests are performed in use class 3 applications (above ground, not covered). The first signs of decay on beech wood are visible after few months of exposure. Afterwards the decay proceeds and the samples are degraded between 4 and 6 years of exposure. The most important reasons for insufficient outdoor performance of beech wood are lack of biologically active extractives and low water exclusion efficacy. In order to elucidate this phenomenon moisture content was continuously monitored for 15 months. We believe that the field tests performed will lead us to the data which will enable better understanding of the phenomena of durability and improve durability of beech wood with state of the art modification solutions

Service life of beech wood in outdoor applications

Bukovina sodi med najpomembnejše lesne vrste v Sloveniji. Standard SIST EN 350-2 uvršča bukovino med lesne vrste z najslabšo odpornostjo proti lesnim glivam. To je eden izmed najpomembnejših razlogov, ki preprečuje uporabo bukovine na prostem. Večina podatkov o odpornosti bukovine temelji na laboratorijskih testiranjih, realnih terenskih testov pa je relativno malo. Življenjska doba bukovine je v veliki meri odvisna od lokalnih podnebnih razmer, zato je nujno določiti življenjsko dobo posameznih lesnih vrst na prostem v osrednji Sloveniji. Na Oddelku za lesarstvo zato že več let potekajo testi, s katerimi določamo odpornost bukovine v tretjem razredu uporabe (na prostem, ni v stiku z zemljo). Prvi znaki glivnega razkroja se pojavijo že po nekaj mesecih izpostavitve, kasneje se razkroj nadaljuje, vzorci pa povsem propadejo po 4 do 6 letih izpostavitve. Glavni razlog za dovzetnost bukovine za glivni razkroj je povezan z odsotnostjo biološko aktivnih snovi (ekstraktivov) in dejstvom, da se bukovina relativno hitro navlaži. Z namenom proučiti dinamiko vlaženja bukovine smo petnajst mesecev stalno spremljali vlažnost lesa v različnih razmerah uporabe. Pričakujemo, da bomo skozi daljše obdobje spremljanja relevantnih lastnosti bukovine, preostalih lesnih vrst in modificiranega lesa pridobili podatke, ki bodo omogočili širšo rabo bukovega lesa na prostem.Beech wood is amongst the most important wood species in Slovenia. The EU standard EN 350-2 classifies beech wood into the group of the least durable wood species. This is one of the most important reasons which limit the use of beech wood in outdoor applications. The majority of the data about beech wood durability is a result of laboratory tests as there were limited numbers of field tests performed. As the service life of wood significantly depends on the local climate conditions, this data cannot be simply copied from other countries. Therefore, field tests have been running at the field test site of the Department of Wood Science and Technology for several years now to determine comprehensive performance of most important Slovenian wood species including beech wood. Majority of the tests are performed in use class 3 applications (above ground, not covered). The first signs of decay on beech wood are visible after few months of exposure. Afterwards the decay proceeds and the samples are degraded between 4 and 6 years of exposure. The most important reasons for insufficient outdoor performance of beech wood are lack of biologically active extractives and low water exclusion efficacy. In order to elucidate this phenomenon moisture content was continuously monitored for 15 months. We believe that the field tests performed will lead us to the data which will enable better understanding of the phenomena of durability and improve durability of beech wood with state of the art modification solutions

Model za določanje življenjske dobe lesa listavcev

The majority of Slovenian wood species do not have durable wood. Due to increased environmental awareness, users are avoiding treated wood and wood from tropical forests. In order to increase the consumption of domestic wood species, we have to understand the overall performance of wood better. Therefore, a study of the most important Slovenian hardwood species was performed, as prescribed by Meyer-Veltrup et al. Durability against wood decay fungi and wetting was determined using standard laboratory tests. These data were then used for calculation of the respective factors needed for calculation of predicted service life