Primerjava kolorimetričnega testa MTT in testa klonogenosti na mišjih fibrosarkomskih SA-1 celicah po obsevanju in zdravljenju s cisplatinom

Background. The aim of our study was to determine the relationship between cell survival of SA-1 tumor cells measured by clonogenic assay and MTT assay after irradiation and cisplatin treatment. Materials and methods. Survival of SA-1 cells was measured after irradiation (2-8 Gy) and cisplatin treatment (0.05-0.5 u g/ml) by clonogenic assay performed 7 days after treatment, and byMTT assay performed on day 3, 4, 5, and 7 after the treatment. Results. The results showed good correlation between MTT assay and clonogenic assay for irradiation doses below 4 Gy. For higher doses good correlation between MTT and clonogenic assay was determined only when MTT assay was performed on day 5and 7 after the treatment. In the case of cisplatin treatment, similar pattern was observed, good correlation between IC50 values for MTT and clonogenic assay was found when MTT assay was performed on day 5 and 7 after the treatment. Conclusion. Results of our study confirmed the results of previous studies addressing this topic and further support the use of MTT testas an alternative test for clonogenic test as a predictive assay of tumourresponse to the radio or chemotherapy.Izhodišče. Namen naše raziskave je bil določiti povezavo med testom MTT in testom klonogenosti z merjenjem preživetja SA-1 tumorskih celic po obsevanju in po terapiji s cisplatinom. Materiali in metode. Preživetje SA-1 celic smo določali po obsevanju celic (2-8 Gy) ali po terapiji s cisplatinom (0.05 - 0.5ug/ml) s testom klonogenosti, ki smo ga izvedli 7 dan po terapiji, ter testom MTT, ki smo ga izvedli 3., 4., 5., in 7. po terapiji. Rezultati. Ugotovili smo, da testa dobro korelirata, ko smo celice obsevali z dozami pod 4 Gy. Pri višjih dozah obsevanja sta test MTT in test klonogenosti dobro korelirala samo v primeru, ko smo merili preživetje celic z testom MTT 5. in 7. dan po obsevanju. Po terapiji s cisplatinom smo dobili podobne rezultatekorelacija med testom MTT in testom klonogenosti je bila dobra v primeru, ko smo izvedli test MTT 5. in 7. dan po terapiji. Zaključki. Rezultati naše raziskave so potrdili ugotovitve predhodnih študij, ter podpirajo uporabo testa MTT kot alternativo testu klonogenosti pri napovedovanju izida zdravljenja tumorjev z radio- in kemoterapijo

The influence of micro and macro porosity of paper on wet repellence mottling in offset printing

Fountain solution induced mottling in offset printing manifests as nonhomogenous printing area with optical variation has several influencing factors. One mechanism is that the fountain solution from the previous printing unit has no time to absorb into the coating before ink transfer or the ink cannot emulsify the water and stays on top of the ink surface as an additional hydrophilic layer. In paper coating development, the paper chemistry influences the surface chemistry features of the inkpaper coating interaction and can cause water repellency. Porosity and the absorbing capacity of paper and its coating is of great importance to avoid press related problems. In this paper, we have examined paper substrates which were reported to cause wet repellence mottling and tested their porosity ratio of micro and macro pores and their water/ ink absorption properties. The micro macro porosity was determined by using easy and low-cost proprietary technique for the porosity ratio determination. We have measured ink stabilization values, penetration dynamics, wet repellence mottling and micro and macro porosity on paper samples printed with laboratory sheet-fed offset printing. We have found that the lower number of macropores and non-optimal micro and macropore distribution influenced the occurrence of water induced wet repellence and lowered the optical homogeneity of the samples

Influence of Ink Curing in UV LED Inkjet Printing on Colour Differences, Ink Bleeding and Abrasion Resistance of Prints on Textile

Digital printing techniques are increasingly present in the field of textile printing. Particularly prominent is the inkjet printing technique using water-based inks, UV LED inkjet printing also increasingly being in use. UV LED inkjet is primarily not intended for direct clothing printing; however, it can be used especially as a hybrid solution in the soft signage market. It is a great option for the printers that are not engaged only in textile printing, and want a more versatile print portfolio, extending it to non-clothing textile products, e.g. soft signage and non-wearable products. As these types of products often require colour reproduction of logos, accurate colour reproduction, good ink adhesion and sharpness are important just like in other printing technologies. In order to evaluate the impact of UV LED radiation amount on colour differences, ink bleeding and abrasion resistance, six different fabric samples (five woven and one nonwoven) were printed using a UV LED inkjet printer. Based on the results of colour difference, it was established that a reduction of UV radiation (by half the manufacturer’s recommended amount) had no effect on this parameter. However, perceptible colour differences were observed with the use of different M measurement conditions defined by the international standard ISO 13655-2017. Reducing the amount of UV radiation had no effect on the adhesion and durability of the printed ink. Small differences detected in these two parameters were mainly a consequence of the properties of textile materials and not of decreased UV radiation

Development of Electrospun Films from Wastewater Treatment Plant Sludge

Electrospinning is a versatile method for producing continuous polymer nanofibers, including from wastewater treatment plant sludge (WTPS). In this context, purified WTPS was successfully used to produce electrospun fibers. The main objective of our research was to produce new, local, circular, renewable and environmentally friendly packaging material. The aim of the research was to purify and treat WTPS to make it suitable for the electrospinning process, thus producing a new material and chemically characterizing it in the first step. One of the major advantages of our process was that the electrospinning process could be carried out with water and ethylenediaminetetraacetic acid. The optimal viscosity was determined to be 20,000 mPas in order to produce sufficient nanofibers. Analyses such as Fourier-Transform Infrared Spectroscopy (FTIR) and 1H-NMR (proton nuclear magnetic resonance) were used to determine the substances of unpurified and purified WTPS. The tensile properties, contact angle, surface properties and differential scanning calorimetry of the final material were determined and used. The 1H-NMR analysis confirmed the presence of a small quantity of polyhydroxyalkanoates in the samples. Based on the properties, the final material was brittle and less stretchable compared to electrospun packaging films available in the market

Functional Nanocellulose, Alginate and Chitosan Nanocomposites Designed as Active Film Packaging Materials

The aim of the study was to characterize and compare films made of cellulose nanocrystals (CNC), nano-fibrils (CNF), and bacterial nanocellulose (BNC) in combination with chitosan and alginate in terms of applicability for potential food packaging applications. In total, 25 different formulations were made and evaluated, and seven biopolymer films with the best mechanical performance (tensile strength, strain)—alginate, alginate with 5% CNC, chitosan, chitosan with 3% CNC, BNC with and without glycerol, and CNF with glycerol—were selected and investigated regarding morphology (SEM), density, contact angle, surface energy, water absorption, and oxygen and water barrier properties. Studies revealed that polysaccharide-based films with added CNC are the most suitable for packaging purposes, and better dispersing of nanocellulose in chitosan than in alginate was observed. Results showed an increase in hydrophobicity (increase of contact angle and reduced moisture absorption) of chitosan and alginate films with the addition of CNC, and chitosan with 3% CNC had the highest contact angle, 108 ± 2, and 15% lower moisture absorption compared to pure chitosan. Overall, the ability of nanocellulose additives to preserve the structure and function of chitosan and alginate materials in a humid environment was convincingly demonstrated. Barrier properties were improved by combining the biopolymers, and water vapor transmission rate (WVTR) was reduced by 15–45% and oxygen permeability (OTR) up to 45% by adding nanocellulose compared to single biopolymer formulations. It was concluded that with a good oxygen barrier, a water barrier that is comparable to PLA, and good mechanical properties, biopolymer films would be a good alternative to conventional plastic packaging used for ready-to-eat foods with short storage time

Development of polymer packaging materials from renewable resources

Doktorsko delo temelji na treh znanstvenih člankih s področja razvoja trajnostnih polimernih embalažnih materialov. V sklopu raziskav za pripravo omenjenih člankov so bili z uporabo večinoma lokalno dostopnih surovinskih virov razviti novi, različni, trajnostni, polimerni embalažni materiali, ki bodo v prihodnje lahko služili kot alternativa običajnim, osnovanim iz naftnih derivatov. Prav tako so bili pripravljeni premazi iz obnovljivih virov, ki služijo predvsem za izboljšanje bariernih lastnosti papirjev ter bodo v prihodnje lahko predstavljali nadomestek nekaterim sintetičnim premazom. V prvi fazi raziskav je bil s postopkom elektropredenja iz mulja, ki nastaja pri čiščenju odpadnih komunalnih vod, pridobljen nov, gibek, tanek material, potencialno uporaben za embalažne namene. Mulj je bil pred postopkom elektropredenja očiščen z uporabo etilendiamintetraocetne kisline. Sestavo in čistost mulja smo določali z uporabo infrardeče spektroskopije s Fourierjevo transformacijo, bližnje infrardeče spektroskopije in termogravimetričnih analiz. Za najnatančnejše analize, smo se posluževali jedrske magnetne resonance. Z nateznim testom smo analizirali mehanske lastnosti novo razvitega materiala, z uporabo elektronskega vrstičnega mikroskopa pa njegovo homogenost in morfološke značilnosti. V drugi fazi raziskave so bili s postopkom vlivanja izdelani tanki, gibki filmi, katerih glavne komponente so bile: bakterijska nanoceluloza (pridobljena iz alternativnega surovinskega vira – kisove matice), nanokristalinična in nanofibrilirana celuloza, alginat ter hitozan. Vse komponente filmov so bile pred vlivanjem okarakterizirane z uporabo različnih analitičnih tehnik. Novo razvite filme smo okarakterizirali predvsem z vidika fizikalno–mehanskih lastnosti (natezne lastnosti) in bariernih lastnosti (prepustnost za vodno paro in kisik), pri čemer smo določili vpliv sestave na omenjene lastnosti. V zadnjem delu raziskav smo preučevali vpliv različnih premazov na barierne lastnosti komercialno dobavljivega, industrijsko izdelanega papirja. Sprva smo pripravili premazne mešanice, osnovane na škrobu, z dodanimi različnimi deleži ligninov iz različnih surovinskih virov. Premazne mešanice smo nato nanesli na površino izbranega papirja. Z meritvami prepustnosti vodne pare, odpornosti na maščobe, olja itd. premazanih papirjev smo določili vpliv bio-osnovanih premazov na barierne lastnosti, prav tako smo določili tudi mehanske in fizikalne lastnosti papirja.The PhD thesis is based on three scientific papers from the field of development of sustainable polymer packaging materials. The research for these papers has resulted in new, different, sustainable, polymeric packaging materials, using mostly locally available raw material sources, which could serve as an alternative to conventional petroleum-based materials in the future. Coatings from renewable sources have also been developed, which serve mainly to improve the barrier properties of papers and may in the future provide a substitute for some synthetic coatings. In the first phase of the research, a new, flexible, thin material, potentially useful for packaging purposes, was obtained by electrospinning from sludge produced during the treatment of municipal wastewater. The sludge was cleaned using ethylenediaminetetraacetic acid prior to the electrospinning process. The composition and purity of the sludge were determined using Fourier transform infrared spectroscopy, near-infrared spectroscopy, and thermogravimetric analyses. For the most accurate analyses, nuclear magnetic resonance was used. The mechanical properties of the newly developed material were analysed by tensile tests and its homogeneity and morphological characteristics were analysed by electron line microscopy. In the second phase of the research, thin, flexible films were produced by a casting process, the main components of which were: bacterial nanocellulose (obtained from an alternative raw material source - vinegar nut), nanocrystalline and nanofibrillated cellulose, alginate, and chitosan. All film components were characterised prior to casting using different analytical techniques. The newly developed films were characterised mainly in terms of mechanical-physical properties (tensile properties) and barrier properties (water vapour and oxygen permeability), and the influence of composition on these properties will be determined. In the last part of the research, the influence of different coatings on the barrier properties of commercially available, industrially produced paper was investigated. Initially, starch-based coating blends were prepared with different proportions of lignins from different raw material sources added. The coating blends were then applied to the selected paper. By measuring the water vapour permeability, fat, and oil resistance, etc. of the coated papers, the influence of the bio-based coatings on the barrier properties was determined, as well as the mechanical and physical properties of the paper

The influence of nanofibrillated cellulose on mechanical and printing properties of packaging paper

Papirji in kartoni, namenjeni embaliranju, morajo dosegati čim boljše mehanske lastnosti ob čim nižji masi oz. gramaturi, hkrati pa morajo imeti tudi primerne površinske lastnosti za tiskanje v različnih tiskarskih tehnikah. Za doseganje teh lastnosti se jim vse pogosteje dodaja nanoceluloza. Nanoceluloza je sodoben, naravni nanomaterial z izjemnimi mehanskimi lastnostmi, ki se ga lahko pridobiva s kemijskimi, z mehanskimi ali z biološkimi postopki oz. s kombinacijo le-teh. Glede na način pridobivanja, dimenzije in druge lastnosti, se nanoceluloza loči na: nanofibrilirano celulozo (NFC), nanokristalinično celulozo (NCC) in bakterijsko nanocelulozo (BNC). V raziskavi je bil preučen vpliv dodatkov NFC in BNC, pridobljenih iz alternativnih surovinskih virov, na osnovne, mehanske, površinske, optične in tiskarske lastnosti embalažnega papirja, ki bi se lahko uporabljal kot t. i. nepremazan, beljen kraft liner. V raziskavi je bila nanofibrilirana celuloza pridobljena iz japonskega dresnika, ki je ena izmed najbolj invazivnih tujerodnih rastlin pri nas. Poleg nanofibrilirane celuloze je bila iz stranskega produkta, ki nastaja pri klasičnem postopku pridobivanja kisa, pridobljena tudi bakterijska nanoceluloza. Z namenom določitve vpliva dodatka različnih nanoceluloz na lastnosti papirja so bili iz beljenih, sulfatnih, evkaliptusovih celuloznih vlaken z dodanim kationskim škrobom in 10 oz. 20 % NFC ali BNC oblikovani laboratorijski listi. Analiza osnovnih, mehanskih, površinskih in tiskarskih lastnosti je pokazala, da dodatek obeh vrst nanoceluloze pozitivno vpliva na večino izmerjenih lastnosti papirja. Posledično sledi zaključek, da je tovrstna nanoceluloza primerna za uporabo v papirništvu, kljub temu, da je bila proizvedena iz alternativnih surovinskih virov.Paper and board for packaging must have as good mechanical properties as possible at the minimum possible weight or grammage. At the same time, they must achieve suitable surface properties for printing with different printing techniques. To achieve these properties, nanocellulose often added to them. Nanocellulose is a modern, naturally based nanomaterial, with exceptional mechanical properties. It can be obtained with chemical or mechanical procedures, with the use of appropriate microorganisms or with a combination of these approaches. Depending on the method of production, dimensions and other properties, nanocellulose can be classified as nanofibrilated cellulose (NFC), nanocrystalline cellulose (NCC), and bacterial nanocellulose (BNC). The purpose of our research was to determine the impact of two different types of nanocellulose, obtained from alternative raw materials, on basic, mechanical, surface, optical and printing properties of packaging paper, potentially used as uncoated, bleached kraft liner. In the research, nanofibrilated cellulose was obtained from Japanese knotweed, which is one of the most invasive plants in Europe. Beside nanofibrillated cellulose, BNC was obtained from a by-product formed during the classical vinegar production. To determine the effect of nanocellulose addition on paper properties, laboratory sheets were formed of kraft, bleached, eucalyptus cellulose fibers, with cationic starch and 10% or 20% of NFC or BNC added. Analyses of basic, mechanical, surface and printing properties have shown that the addition of both types of nanocellulose had a positive effect on most of the measured paper properties. Based on the results of the research it can be concluded, that both obtained nanocelluloses are suitable for use in papermaking, despite the fact that they have been produced from alternative raw materials

Organosolv Lignin Barrier Paper Coatings from Waste Biomass Resources

The aim of the study was to isolate lignin from organosolv, beech tree (Fagus sylvatica), and Japanese knotweed (Reynoutria japonica), to use it for paper surface and to replace part of the non-renewable product resources with bio-based ones. A total of nine coated samples with different lignin formulations and starch were compounded, prepared, and evaluated. The basic (grammage, thickness, specific density), mechanical (elongation at break, tensile, burst and tear indices), and barrier properties (contact angle, water penetration, water vapour permeability, kit test) of the coated papers were investigated. The analysis showed no significant difference in tensile properties between uncoated and coated samples. Furthermore, the decrease in water vapour transmission rate and the lower contact angle for coated samples were nevertheless confirmed. The novel coating materials show promising products with very good barrier properties. Finally, the correlation between structural, morphological, and (other) natural lignin-based factors was revealed, highlighting the importance of parameters such as the equivalence ratio of aliphatic and phenolic hydroxyl groups or the average molecular weight. Tuning functionality by design could optimise performance in the future

DEVELOPMENT OF MOULDED PULP PROTECTIVE PACKAGING FROM ALTERNATIVE FIBERS

<p>Expanded polystyrene foam is a standard protection element for many packaging solutions which needs cushioning properties against mechanical stresses. While its protective functions are very good (lightweight good cushioning properties, easy to 3D-form with tooling) the environmental aspect of this material is questionable due to bulkiness (high space volume) and low rates of real and viable recycling infrastructure. Due to that producers have switched to fiber solutions (corrugated board inserts, fiber foams and biopolymer fiber composites) as an alternative solution. Even though this fiber-based alternative solutions are environmentally friendlier the overuse of cellulose fibers from wood sources can also be a burden on the environment. On the other hand, invasive alien plants due to their negative impact on biodiversity and other economic damage (riverbank degradation) are one of the possible solutions for producing fiber elements.</p><p>In this paper the development of moulded fiber cushioning elements, made from locally sourced invasive fiber alien plants (Japanese knotweed and Canadian goldenrod) and processed in Slovenia is presented as a part of the protective packaging system for household appliances. The fiber morphology and processing as well the prototyping of the moulding tools have influenced the mechanical properties needed for protection simulation due to different fiber bonding and entanglement. The obtained results serve as a basis for further development and structural analysis (finite elements modelling) of stress points for building simulation software for the use of alternative fiber solutions.</p&gt