Cellulose Fibre-Reinforced Biofoam for Structural Applications

Traditionally, polymers and macromolecular components used in the foam industry are mostly derived from petroleum. The current transition to a bio-economy creates demand for the use of more renewable feedstocks. Soybean oil is a vegetable oil, composed mainly of triglycerides, that is suitable material for foam production. In this study, acrylated epoxidized soybean oil and variable amounts of cellulose fibres were used in the production of bio-based foam. The developed macroporous bio-based architectures were characterised by several techniques, including porosity measurements, nanoindentation testing, scanning electron microscopy, and thermogravimetric analysis. It was found that the introduction of cellulose fibres during the foaming process was necessary to create the three-dimensional polymer foams. Using cellulose fibres has potential as a foam stabiliser because it obstructs the drainage of liquid from the film region in these gas-oil interfaces while simultaneously acting as a reinforcing agent in the polymer foam. The resulting foams possessed a porosity of approximately 56%, and the incorporation of cellulose fibres did not affect thermal behaviour. Scanning electron micrographs showed randomly oriented pores with irregular shapes and non-uniform pore size throughout the samples.Peer reviewe

Neonatal screening of hearing function by otoacustic emissions - a single center experience

Background/Aim. Nowadays development of techniques enables detection of hearing impairment in a very short time, immediately after birth by using otoacoustic emissions. They are low-pitched sounds produced in physiologically clear cochlea and can be recorded in cochlear outer meatus. By this method, complete data are found on a whole presynaptic auditory nervous system functioning that has mostly been affected by pathological changes making it a perfect screening test. Reliability and sensibility of this method is up to 98%. The aim of this study was to present the first results of systematic neonatal screening of hearing function by otoacoustic emissions in the Clinical Center Kragujevac (Kragujevac, Serbia). Methods. This prospective study of neonatal hearing screening function, initiated systematically by the 2008 at the Clinical Center Kragujevac, included full-term newborns and premature born ones, within the first 24 h after birth, using a DPOAEs interacoustics otoread-screener. Retesting was done after a month. Results. From January 1st, 2009 to December 1st, 2010, a total number of examined infants by this method was 1,994 out of which 1,778 were full-term and 216 were premature born. The test passing was higher in the group of full-term babies (92.5%) than in the preterm ones (55.1%). No bilateral answers were recorded in premature born children compared to the full-term ones, of whom a larger number was with missing lateral responses. The results of re-examination test in the group of full-term born and premature newborns were 83.7%, and 61%, respectively. Conclusion. Deliberately provoked transient otoacoustic emission is an efficient method in testing hearing function in newborns, since it is non-invasive, rapid and objective. Its correlation with audibly evoked potentials is very high, which confirms its reliability

Distribution of EGFR SNPs -191C/A and 181946G/A in patients with lung cancer depending on smoking status in the Republic of Srpska, Bosnia and Herzegovina

To analyze the frequencies of two single nucleotide polymorphisms (SNPs) of EGFR gene, -191C/A and 181946G/A, among lung cancer patients from the Republic of Srpska, Bosnia and Hercegovina, as well as to assess the association of SNP genotypes with the cancer type and other demographic characteristics of patients, particularly with the smoking status.Publishe

Nitric oxide, thyroglobulin, and calcitonin: unraveling the nature of thyroid nodules

BackgroundThyroid nodules (TN) are localized morphological changes in the thyroid gland and can be benign or malignant.ObjectiveThe present study investigates the relationships between biochemical markers in serum (s) and their homologs in washout (w) after fine-needle aspiration biopsy (FNAB) of the TN of interest and their correlation with cytology specimen findings.MethodsWe investigated the relationships between serum biochemical markers nitric oxide (NO), thyroglobulin (TG), and calcitonin (CT), their homologs in washout after FNAB of the TN of interest, and cytology findings of biopsy samples classified according to the Bethesda system for thyroid cytopathology in this study, which included 86 subjects.ResultsWashout TG (TGw) level positively correlates with the cytology finding of the biopsy. A higher level of TGw correlates with higher categories of the Bethesda classification and indicates a higher malignant potential. The levels of serum NO (NOs), serum TG (TGs), serum CT (CTs), and washout CT (CTw) do not correlate with the cytology finding of the biopsy, and the higher levels of washout NO (NOw) correspond to the more suspicious ultrasound findings.ConclusionThe findings of our study suggest that TGw and NOw could be used as potential predictors of malignancy in TN

Engineering of novel cellulose-based biocomposites and biofoams

Biomass is a renewable feedstock for producing fine chemicals, polymers, energy, and a variety of commodities. Transformation of biomass into diverse valuable products is the key concept of a bioeconomy. Chemical and mechanical conversion of biomass, which reduces the use of toxic chemicals is one of the important approaches to improve the profitability of bioeconomy. Utilization of green materials under environmentally-friendly conditions, was the main goal of this research. Wood fibres were converted into cellulose-based 3D objects through swelling of cellulose fibres in an N,N-dimethylacetamide and lithium chloride solvent system followed by a moulding step. Swollen cellulose pulp in the form of gel was solidified with two different anti-solvents. The choice of solidification solvent had a great influence on the structure and mechanical properties of the final cellulose material which was studied with x-ray diffraction and nanoindentation technique. The mechanical properties and optical properties of solid swollen cellulose fibres can be significantly increased with forging technique. Bio-based composite materials composed of a mixture of shellac resin and cellulose fibres were developed. The influence of the reinforcement content and the concentration of additives on the mechanical performance and processing were investigated. A high amount of cellulose and low concentrations of ethanol and polyethylene glycol produced bio-based composites with high stress resistance, while a low amount of cellulose and high concentration of additives provided specimens with an increased elasticity. Acrylated epoxidized soybean oil and variable amounts of wood fibres were used in a production of bio-based foam. The developed macroporous polymers were characterized by several techniques, including porosity measurements, nanoindentation testing, scanning electron microscopy and thermogravimetric analysis. It was found that the introduction of pulp fibres during the foaming process was necessary to create the polymer foams. Cellulose fibres behaved as foam stabilizer while simultaneously acting as reinforcing agent in the polymer foam.Biomassa är ett förnybart råmaterial för att tillverka finkemikalier, polymerer, energi och en mängd handelsvaror. Omvandling av biomassa till diverse värdefulla produkter är nyckelkonceptet för ett bioraffinaderi. Kemisk och mekanisk konvertering av biomassa, vilket minskar användningen av giftiga kemikalier, är ett av de viktigaste tillvägagångssätten för att förbättra bioekonomins lönsamhet. Användningen av gröna material under miljövänliga förhållanden var huvudmålet för denna forskning. Vedfibrer konverterades till cellulosabaserade 3D-objekt genom svällning av cellulosafibrer i ett lösningssystem av N,N-dimetylacetamid och litiumklorid, med ett därpå följande formningssteg. Uppsvälld cellulosamassa i gelform solidifierades med två olika antilösningsmedel. Valet av solidifieringslösningsmedel hade en stor inverkan på strukturen och de mekaniska egenskaperna av det slutliga cellulosamaterialet, vilket undersöktes med XRD- och nanoindeteringsmetoder. De mekaniska och optiska egenskaperna av fasta svullna cellulosafibrer kan väsentligt ökas genom formningtekniker. Biobaserade kompositmaterial bestående av en blandning av schellackharts och cellulosafibrer utvecklades. Inverkan av armeringsmaterialhalten och koncentrationen av tillsatsmedel på den mekaniska prestandan och processeringen undersöktes. En hög halt av cellulosa och låga koncentrationer av etanol och polyetylenglykol producerade bio-baserade kompositer med hög spänningstålighet, medan en låg halt av cellulosa och en hög koncentration av tillsatsmedel ledde till prov med en ökad elasticitet. Akrylerad epoxiderad sojabönsolja och en varierande mängd av vedfibrer användes för att tillverka bio-baserat skum. De utvecklade makroporösa materialen karakteriserades med flera tekniker, bland annat porositetsmätningar, nanoindentering, SEM och termogravimetrisk analys. Det upptäcktes att införandet av massafibrer under skumtillverkningsprocessen var nödvändig för att skapa polymerskummen. Cellulosafibrerna fungerade som skumstabilisatorer samtidigt som de verkade som armeringsmedel i polymerskummet

Preparation and Characterisation of Cellulose-Shellac Biocomposites

Composite materials comprising a mixture of shellac resin as the matrix and cellulose as the reinforcement were developed. The influence of the reinforcement content and the concentration of additives on the mechanical performance and processing were investigated. A high content of cellulose and low concentrations of ethanol and polyethylene glycol produced biocomposites with high stress resistance and a high Young’s modulus, whereas a low content of cellulose and a high concentration of additives gave samples a low Young’s modulus and high elasticity. Two types of cellulose-based reinforcements with different polarity, namely, mechanically refined wood pulp and cellulose acetate butyrate particles, were compared. The efficiency of the composite over the two model reinforcements, i.e., hydrophilic and hydrophobic components, respectively, was also studied. Although particle reinforcement was easier to process and evenly dispersed into the matrix, its mechanical performance was lower compared with refined fibres. Scanning electron microscopy showed that the matrix better coated the fibres than the particles, resulting in better adhesion and mechanical performance. The morphology of reinforcement played a key role; long fibres oriented in the pulling direction ensured a better mechanical resistance than particle fillers

Epidermal Growth Factor Receptor Gene in Non-Small-Cell Lung Cancer: The Importance of Promoter Polymorphism Investigation

Recently, epidermal growth factor receptor (EGFR) was a key molecule in investigation of lung cancer, and it was a target for a new therapeutic strategy, based on molecular analyses. In this review, we have summarized some issues considering the role of EGFR in lung cancer, its coding gene, and its promoter gene polymorphisms (SNPs) -216G/T and -191C/A in non-small-cell lung cancer (NSCLC). The position of the SNPs indicates their significant role in EGFR regulation. The accumulation of knowledge regarding SNPs lately suggests their significant and important role in the onset of carcinogenesis, the prediction of the onset of metastases, the response to therapy with TKI inhibitors, and the onset of toxic effects of the applied therapy. Based on this, we suggest further studies of the relationship of clinical significance to SNPs in patients with lung tumors

High-pressure Treatment of DMAc/LiCl Swollen Softwood Pulp

Swollen softwood cellulose pulp in a DMAc/LiCl solvent system was compressed under elevated pressure (up to 900 MPa) in a Bridgman anvil press. The influence of high pressure on two cellulose systems was studied by measuring X-ray diffraction, mechanical and optical properties and observing scanning electron micrographs of the morphology. Compressed swollen cellulose, washed with distilled water, had lower elastic modulus and hardness compared to swollen cellulose washed with a combination of 2-propanol and deionized water. This work showed that material with lower mechanical properties will be affected more by compression and will result in higher mechanical properties after pressure treatment. Transmitted light in the visible range for both systems was increased after elevated pressure was applied. The XRD measurements revealed the decrease of the cellulose crystallinity after high pressure treatment for all swollen cellulose samples. The morphology of the compacted samples showed noticeable differences between the compact smooth surface and the layered core.</p

Preparation of three-dimensional cellulose objects previously swollen in a DMAc/LiCl solvent system

International audienceThree-dimensionally shaped cellulosic objects were produced via a two-step procedure: swelling of softwood pulp (93 % cellulose; 4.5 % hemicellulose; 54 % crystallinity) in DMAc/LiCl followed by moulding. Swollen cellulose pulp in the form of gel was solidified with two different anti-solvents: distilled water and a combination of 2-propanol and deionized water. The solid cellulose material was further moulded in a custom-built prototype mould. The role of the anti-solvent was to solidify the swollen cellulose fibres and prepare mouldable solid specimens. The anti-solvent was chosen based on the following criteria, viz., recoverability, stable chemical reactivity, availability, cost and previous research in the anti-solvent area. The choice of solidification solvent had a great influence on the structure and mechanical properties of the final cellulose material. Results of different characterisation techniques showed that when the cellulose gel was washed with distilled water, it had a significantly higher number of lithium cations (ICP-MS and Raman), amorphous structure (X-ray) and lower mechanical properties (nanoindentation) compared to samples washed with a combination of 2-propanol and deionized water. An increase in viscosity as previously reported and changes in the NMR and IR spectra of DMAc upon LiCl suggested the formation of an ion-dipol complex, where lithium cations reside adjacent to the oxygen of the carbonyl group of DMAc. The formed macrocation [DMAcn + Li]+ was preserved between cellulose chains in cellulose specimens washed with distilled water and had an essential role in the disruption of initial bonds, thus enhancing mouldability. Electron microscopy (FE-SEM) studies showed that the surface of cellulose after mechanochemical treatment was rough with no presence of fibre

High-pressure Treatment of DMAc/LiCl Swollen Softwood Pulp

Swollen softwood cellulose pulp in a DMAc/LiCl solvent system was compressed under elevated pressure (up to 900 MPa) in a Bridgman anvil press. The influence of high pressure on two cellulose systems was studied by measuring X-ray diffraction, mechanical and optical properties and observing scanning electron micrographs of the morphology. Compressed swollen cellulose, washed with distilled water, had lower elastic modulus and hardness compared to swollen cellulose washed with a combination of 2-propanol and deionized water. This work showed that material with lower mechanical properties will be affected more by compression and will result in higher mechanical properties after pressure treatment. Transmitted light in the visible range for both systems was increased after elevated pressure was applied. The XRD measurements revealed the decrease of the cellulose crystallinity after high pressure treatment for all swollen cellulose samples. The morphology of the compacted samples showed noticeable differences between the compact smooth surface and the layered core