Influence of carbon nanotube modification on polyurethane properties

U ovom radu prvo su karakterizirane višestijene ugljikove nanocjevčice (MWCNT) te MWCNT modificiranih –COOH skupinama. Karakterizacija MWCNT, MWCNT-COOH provedena je Ramanovom spektroskopijom, termogravimetrijskom analizom, zatim pomoću pretražne elektronske mikroskopije, mjerenjem kontaktnog kuta, te određivanjem disperzivnosti u različitim otapalima. Zatim je istraživan učinak dodatka MWCNT te MWCNT–COOH u rasponu udjela od 0-4% mas. na svojstva poliuretana. Uzorci nanokompozita pripravljani su postupkom iz otopine poliuretana u acetonu te polaganim sušenjem otopina na sobnoj temperaturi. Učinak dodatka nanopunila na sferolitnu strukturu poliuretana te raspodjeljenost nanopunila u PU matrici anlizirana je optičkom polarizacijskom mikroskopijom. Toplinska svojstva u neizotermnim i izotermnim uvjetima istraživana su diferencijalnom pretražnom kalorimetrijom (DSC), a toplinska stabilnost termogravimetrijskom analizom (TGA). Električna provodnost uzoraka određivana je metodom četiri kontakta. Utjecaj dodatka punila na mehanička svojstva PU kompozita ispitana je testom jednoosnog istezanja. Ramanova spektroskopija pokazala je da MWCNT imaju veći udio nečistoća nego MWCNT-COOH. TGA analiza pokazala je da su MWCNT-COOH toplinski stabilnije od MWCNT. Rezultati SEM analize pokazali su da funkcionalizacija ne utječe na stupanj agregacije. Rezultati kontaktni kuteva ukazuju da se funkcionalizacijom s -COOH skupinom uvelike mijenja polarnost nanocijevčica. Rezultati određivanja disperzivnosti pokazali su da su obe vrste nanocjevčica jako dobro dispergirane u acetonu. Optička polarizacijska mikroskopija pokazala je da dodatak oba punila razrušava krupnu sferolitnu morfologiju poliuretana. Uočeno je da su na makrorazini modificirane MWCNT-COOH bolje dispergirane u masi uzorka nego čiste MWCNT. DSC rezultati pokazali su da u neizotermnim uvjetima do određenog udjela dodatak obje vrste MWCNT ubrzavaju kristalizaciju mekog segmenta poliuretana. U uvjetima izotermne kristalizacije MWCNT također znatnije ubrzavaju kristalizaciju nego MWCNT-COOH. Rezultati termogravimetrijske analize upućuju da se dodatkom obje vrste MWCNT znatno poboljšava toplinska stabilnost u čitavom rasponu udjela nanopunila. Rezultati vodljivosti pokazali su da se i dodatakom malih udjela MWCNT vodljivost znatno povećava. Rezultati ispitivanja mehanički svojstava nanokompozita ukazuju da dodatak obje vrste MWCNT punila snižava prekidnu čvrstoću i prekidno istezanje kompozita.In this study carbon nanotubes (MWCNTs) and MWCNTs modified with COOH groups were characterized. Characterization of MWCNTs, MWCNTs-COOH was performed by Raman spectroscopy, thermal analysis, then using scanning electron microscopy, by measuring the contact angle, and determining dispersibility in various solvents. After that the effect of the addition of MWCNTs and MWCNTs-COOH in range of 0-4% wt. on the properties of polyurethane were investigated. Samples of nanocomposite were prepared from solution of polyurethane in acetone and slowly drying the solution at room temperature. The effect of the addition of nanofiller on spherulite structure of polyurethane and distribution nanofiller in PU matrix were analyzed by optical polarization microscopy. Thermal properties in the non-isothermal and isothermal conditions were investigated by differential scanning calorimetry (DSC) and thermal stability by thermogravimetric analysis (TGA). The electrical conductivity of the samples was determined using four probe method. Effect of the addition of fillers on the mechanical properties of PU nanocomposites was examined by uniaxial deformation test. Raman spectroscopy showed that MWCNTs have a higher proportion of impurities than MWCNTs-COOH. TGA analysis showed that MWCNTs-COOH are more thermally stable than MWCNTs. The results of SEM analysis showed that the functionalization does not affect the degree of aggregation. The results of the contact angles indicate that the functionalization by COOH groups significantly changes the polarity of the nanotubes. The results of determining dispersibility showed that both types of nanotubes are very well dispersed in the acetone. Optical polarization microscopy showed that the addition of both nanofillers disrupts the spherulite morphology of polyurethane. It was noted that at the macro level modified MWCNTs-COOH are better distributed in the the sample than pure MWCNTs. DSC results showed that in the non-isothermal conditions up to the addition of a certain amount of both types of MWCNTs accelerate the crystallization of the soft segments of polyurethane. In terms of isothermal crystallization MWCNTs also significantly accelerate crystallization than MWCNTs-COOH. The results of thermogravimetric analysis indicate that the addition of both types of MWCNTs significantly improves the thermal stability. Conductivity results showed that the the addition of small amount of MWCNTs significantly increases the conductivity. The results of the mechanical properties of the nanocomposite show that addition of both types of fillers MWCNTs reduced tensile strength and elongation of the composite

Brain metastases from lung cancer show increased expression of DVL1, DVL3 and beta-catenin and down-regulation of E-cadherin

The susceptibility of brain to secondary formation from lung cancer primaries is a well-known phenomenon. In contrast, the molecular basis for invasion and metastasis to the brain is largely unknown. In the present study, 31 brain metastases that originated from primary lung carcinomas were analyzed regarding over expression of Dishevelled-1 (DVL1), Dishevelled-3 (DVL3), E-cadherin (CDH1) and beta-catenin (CTNNB1). Protein expressions and localizations were analyzed by immunohistochemistry. Genetic alterations of E-cadherin were tested by polymerase chain reaction (PCR)/loss of heterozygosity (LOH). Heteroduplex was used to investigate mutations in beta-catenin. DVL1 and DVL3 showed over expression in brain metastasis in 87.1% and 90.3% of samples respectively. Nuclear staining was observed in 54.8% of cases for DVL1 and 53.3% for DVL3. The main effector of the Wnt signaling, beta-catenin, was up-regulated in 56%, and transferred to the nucleus in 36% of metastases. When DVL1 and DVL3 were up-regulated the number of cases with nuclear beta-catenin significantly increased (p=0.0001). Down-regulation of E-cadherin was observed in 80% of samples. Genetic analysis showed 36% of samples with LOH of the CDH1. In comparison to other lung cancer pathologies, the diagnoses adenocarcinoma and small cell lung cancer (SCLC) were significantly associated to CDH1 LOH (p=0.001). Microsatellite instability was detected in one metastasis from adenocarcinoma. Exon 3 of beta-catenin was not targeted. Altered expression of Dishevelled-1, Dishevelled-3, E-cadherin and beta-catenin were present in brain metastases which indicates that Wnt signaling is important and may contribute to better understanding of genetic profile conditioning lung cancer metastasis to the brain

Influence of Multiwalled Carbon Nanotube Modification on Polyurethane Properties: I. Morphology and Thermal Properties

U ovom radu istraživan je učinak dodatka višestjenih ugljikovih nanocjevčica (MWCNT) te MWCNT-a modificiranog skupinama COOH (MWCNT- COOH) u rasponu masenih udjela od 0 do 4 % na svojstva termoplastičnog poliuretana (PU). Uzorci nanokompozita pripravljani su postupkom polaganog sušenja iz smjese poliuretana i nanopunila u acetonu pri sobnoj temperaturi. Učinak dodatka nanopunila na sferolitnu morfologiju poliuretana te raspodijeljenost nanopunila u matrici PU analizirana je optičkom polarizacijskom mikroskopijom. Toplinska svojstva u neizotermnim i izotermnim uvjetima istraživana su diferencijalnom pretražnom kalorimetrijom (DSC). Optička polarizacijska mikroskopija pokazala je da dodatak oba punila razrušava krupnu sferolitnu morfologiju poliuretana. Utvrđeno je da je modificirani MWCNT-COOH bolje dispergiran u masi uzorka nego čisti MWCNT. Rezultati DSC-a pokazali su da u neizotermnim uvjetima do određenog udjela dodatak obje vrste MWCNT-a ubrzava kristalizaciju mekog segmenta poliuretana, pri čemu je ubrzanje kristalizacije izraženije u sustavima s punilom MWCNT. Vrijednosti entalpija kristalizacije pokazuju da punilo MWCNT, unatoč lošijoj raspodijeljenosti u masi uzorka, znatnije ometa kristalizaciju mekog segmenta PU-a nego MWCNT-COOH. U uvjetima izotermne kristalizacije punilo MWCNT također znatnije ubrzava kristalizaciju poliuretana nego MWCNT-COOH

Whole-genome sequence of the first sequence type 27 Brucella ceti strain isolated from European waters

ABSTRACT Brucella spp. that cause marine brucellosis are becoming more important, as the disease appears to be more widespread than originally thought. Here, we report a whole and annotated genome sequence of Brucella ceti CRO350, a sequence type 27 strain isolated from a bottlenose dolphin carcass found in the Croatian part of the northern Adriatic Sea. </jats:p

Influence of Multiwalled Carbon Nanotube Modification on Polyurethane Properties: II. Mechanical Properties, Electrical Conductivity and Thermal Stability

U ovom radu istraživan je učinak dodatka višestjenih ugljikovih nanocjevčica (MWCNT) te MWCNT-a modificiranog skupinama COOH (MWCNT-COOH) u rasponu masenih udjela od 0 do 4 % na svojstva poliuretana. Uzorci nanokompozita pripravljani su dispergiranjem nanopunila u otopini poliuretana u acetonu te polaganim isparavanjem otapala pri sobnoj temperaturi. Utjecaj punila na mehanička svojstva kompozita ispitan je testom jednoosnog istezanja, a električna provodnost uzoraka određivana je metodom četiri kontakta. Toplinska postojanost istražena je termogravimetrijskom analizom (TGA). Obje vrste punila MWCNT povećavaju modul, ali snižavaju prekidnu čvrstoću i prekidno istezanje kompozita. Rezultati ispitivanja električne provodnosti pokazali su da se, u odnosu na čisti PU koji ima provodnost reda veličine 10–13 S cm–1, provodnost nanokompozita s masenim udjelom punila MWCNT 0,2 % znatno povećava na vrijednost reda veličine 10–6 S cm–1. Daljnjim povećanjem do masenog udjela obje vrste MWCNT-a 4 %, provodnost se dalje povećava do vrijednosti većih od 10–2 S cm–1. Taj učinak povećanja provodnosti neznatno je jače izražen u sustavima s MWCNT-COOH-om. Rezultati termogravimetrijske analize upućuju na to da se dodatkom obje vrste MWCNT-a znatno poboljšava toplinsku postojanost u istraživanom rasponu udjela nanopunila, pri čemu je ovaj učinak nešto izraženiji za sustave s punilom MWCNT. Ovo djelo je dano na korištenje pod licencom Creative Commons Imenovanje 4.0 međunarodna.In this paper, the influence of multiwalled carbon nanotubes (MWCNT) and carbon nanotubes modified with COOH groups (MWCNT-COOH) on the mechanical and electrical properties as well as on thermal stability of polyurethane (PU) were investigated. The samples of nanocomposite were prepared by dispersion of the nanofiller in a solution of polyurethane in acetone, followed by slow evaporation of the solvent at room temperature. The effect of the fillers on the mechanical properties of PU nanocomposites was examined by the uniaxial deformation test, and electrical properties of the samples were determined by the four probe method. Thermal stability was investigated by thermogravimetric analysis (TGA). The addition of both types of MWCNTs fillers increases modulus (Fig. 1), due to higher modulus of the nanofillers. Due to the better distribution in PU matrix and stronger interactions between COOH groups and carbonyl group in PU matrix, nanocomposites with MWCNT-COOH have higher modulus than nanocomposites with MWCNT filler. Most of the composites have lower strength and elongation at break than PU (Figs. 2 and 3). Smaller MWCNT-COOH aggregates and stronger interactions between this filler and the PU matrix cause less pronounced decreasing of strength at break. Compared to the pure PU, with conductivity of the order of 10–13 S cm–1, the conductivity of the nanocomposite with mass fraction of MWCNT nanofiller 0.2 % substantially increases up to the value of the order 10–6 S cm–1 (Fig. 4). A further increase up to 4 % for both types of MWCNTs, resulted in a further increase in conductivity up to values exceeding 10–2 S cm–1. Due to the better distribution in PU matrix and stronger interactions between COOH groups and carbonyl groups in PU matrix, the conductivity increase effect in systems with MWCNTs-COOH is slightly more pronounced. All investigated nanocomposites have potential applications as electric discharge materials and for electrostatic painting. The results of the thermogravimetric analysis indicate that the addition of both types of MWCNTs significantly improves the thermal stability (Figs. 6 and 7). The maximal degradation rate temperature of polyurethane increased by about 45 °C, thereby this effect is slightly more pronounced for systems with MWCNTs (Fig. 7). This work is licensed under a Creative Commons Attribution 4.0 International License

Frequency of loss of heterozygosity of the NF2 gene in schwannomas from Croatian patients

Aim To identify gross deletions in the NF2 gene in a panel of schwannomas from Croatian patients in order to establish their frequencies in Croatian population. Methods Changes of the NF2 gene were tested by polymerase chain reaction/loss of heterozygosity (LOH) using two microsatellite markers, D22S444 and D22S929. Results The analysis with both markers demonstrated that 43.75% of schwannomas exhibited LOH of the NF2 gene. The D22S444 region exhibited 45.5% of LOHs and the D22S929 region exhibited 14.3% of LOHs. Four LOHs were found in Antoni B, 2 in Antoni A, and 1 in Antoni A and B type tumors. Conclusion The frequency of changes observed in Croatian patients is broadly similar to that reported in other populations and thus confirms the existing hypothesis regarding the tumorigenesis of schwannomas and contributes to schwannoma genetic profile helping us to better understand its etiology and treatment

Alergeni kikirikija u uzorcima čokolada, krem-proizvoda i kolača

Tijekom ovog istraživanja prisutnost alergena kikirikija je analizirana ELISA (Enzyme-linked immunosorbent assay) metodom u uzorcima čokolade s lješnjakom i krem-proizvoda iz trgovačkih lanaca te uzorcima kolača koji sadrže kakaove dijelove iz trgovačkog lanca, slastičarnice i objekta javne prehrane, a dobiveni rezultati uspoređeni su sa informacijama o hrani vezanim uz prisutnost alergena kikirikija. U petnaest od šesnaest analiziranih uzoraka zapakirane hrane (čokolada s lješnjakom i krem-proizvodi) detektirani su alergeni kikirikija pri čemu je navod o sadržaju alergena kikirikija, u okviru informacija o hrani, sadržavalo šest takovih proizvoda. Alergeni kikirikija detektirani su i u četrnaest od šesnaest analiziranih uzoraka nepretpakirane hrane, odnosno kolača koji sadrže kakaove dijelove iz trgovačkog lanca, slastičarnice i objekta javne prehrane pri čemu su informacije o hrani ukazivale na sadržaj kikirikija u tri takova proizvoda. Rezultati istraživanja ukazuju na značaj detekcije alergena kikirikija kao skrivenog sastojka u hrani, obzirom da je podatke o tvarima ili proizvodima koji uzrokuju alergije ili netolerancije koji između ostalog uključuju kikiriki i proizvode od kikirikija, potrebno navoditi u okviru obveznih informacija o hrani

Proceedings of the 12th International Conference on Kinanthropology

Proceedings of the 12th Conference of Sport and Quality of Life 2019 gatheres submissions of participants of the conference. Every submission is the result of positive evaluation by reviewers from the corresponding field. Conference is divided into sections – Analysis of human movement; Sport training, nutrition and regeneration; Sport and social sciences; Active ageing and sarcopenia; Strength and conditioning training; section for PhD students