Optička svojstva recikliranih otisaka termokromnih boja

U završnom radu je provedeno recikliranje ofsetnih termokromnih boja procesom deinking flotacije. Termokromne tiskarske boje imaju drugačiji sastav od konvencionalnih ofsetnih tiskarskih boja, stoga je cilj ovog istraživanja utvrditi koliko se dobro one mogu reciklirati. U eksperimentalnom dijelu rada izvršeno je laboratorijsko otiskivanje dviju termokromnih tiskarskih boja, za obje vrste boja korištena je ista tiskovna podloga – bijeli nepremazani papir. Nakon ubrzanog starenja, otisci su pomiješani u jednakim omjerima te su potom reciklirani metodom deinking flotacije u laboratorijskim uvjetima. Prilikom postupka recikliranja izrađeni su laboratorijski listovi i uzorci filter kolača od razvlaknjene papirne mase (pulpe) u fazama prije i nakon provedene deinking flotacije. Također su izrađeni laboratorijski listovi i uzorci filter kolača od pulpe dobivene razvlaknjivanjem neotisnutog bijelog papira radi izrade „slijepe probe“, odnosno referentnog uzorka. Učinkovitost deinking flotacije evaluirana je mjerenjem optičkih karakteristika: ISO svjetline, CIE bjeline na svim izrađenim laboratorijskim listovima i uzorcima filter kolača, kao i pomoću slikovne analize

Pre-B-cell acute lymphoblastic leukemia with bulk extramedullary disease and chromosome 22 (EWSR1) rearrangement masquerading as Ewing sarcoma

We report a 2-year-old female with a subcutaneous tumor who was initially misdiagnosed as suffering from Ewing sarcoma with a positive EWSR1 rearrangement and EWS/FLI1 transcript. After finding lymphoblasts in peripheral blood, the diagnosis of acute lymphoblastic leukemia was established. This necessitated further analysis of the subcutaneous tumor. The tissue was positive for immature B-cell markers and an immunoglobulin heavy chain gene rearrangement, which confirmed the final diagnosis of common type acute lymphoblastic leukemia with bulk extramedullary disease. The patient was treated with chemotherapy and was in remission 30 months after the diagnosis

Bezglutenski proizvodi namijenjeni osobama s celijakijom nisu dobar izvor folata i vitamina B12

The gluten-free diet, the only treatment in coeliac disease, can be nutritionally unbalanced and deficient in several nutrients. Gluten-free products contain much lower levels of B vitamins, especially lower folate concentrations than their gluten-containing counterparts. Folate intake is considered as a major dietary determinant of plasma homocysteine concentration in healthy population. Elevated homocysteine is an independent risk factor for cardiovascular disease and has been associated with osteoporotic fractures, which are an increased risk factor in coeliac disease. The aim of this study is to determine dietary folate intake and plasma homocysteine concentration as metabolic markers of suboptimal intake of folate and B12 in Croatian coeliac patients living on a gluten-free diet. Subjects were 52 coeliac patients (83 % female, age 35±13) adhering to a gluten-free diet. Blood samples were analyzed for plasma homocysteine, serum and red blood cell folate and serum B12. Quantitative food frequency questionnaire was used to measure dietary folate intake. Mean dietary folate intake was 206 mg of dietary folate equivalents (DFE), which was far below the national recommendation of 400 µg of DFE (or 200 μg of folic acid). Mean homocysteine was (9±2) μmol/L (range from 5.42 to 13.90 μmol/L), while elevated homocysteine concentrations (>10 μmol/L) were found in 34 % of subjects. In conclusion, coeliac patients adhering to gluten-free diet included in this study showed low folate intake and suboptimal folate and vitamin B12 status, possibly due to low folate content in gluten-free products. Therefore, folate fortification or enrichment of gluten-free products could be beneficial for coeliac patients and it would be of great interest for the food industry.Bezglutenska prehrana, jedini lijek za oboljele od celijakije, može biti neuravnotežena zbog nedostataka nekih hranjivih tvari. Bezglutenski proizvodi sadrže manju količinu vitamina B, osobito folata, nego slični proizvodi koji sadrže gluten. U zdravih osoba koncentracija homocisteina u plazmi uglavnom ovisi o prehrambenom unosu folata. Povećana vrijednost homocisteina u posljednje se vrijeme povezuje s osteoporozom koja je učestala u osoba s celijakijom. Svrha je ovoga rada utvrditi unos folata i status homocisteina kao metaboličkoga biljega suboptimalnog unosa folata i vitamina B12 u osoba s celijakijom na području Republike Hrvatske. U istraživanju su sudjelovale 52 osobe s celijakijom koje su na bezglutenskoj prehrani (83 % žena, dobi 35±13 godina). Analizom krvi utvrđena je koncentracija homocisteina, folata u serumu i eritrocitima te vitamina B12 u serumu. Kvantitativni je upitnik za procjenu unosa hrane i pića upotrijebljen radi utvrđivanja prehrambenog unosa folata. Prosječni je unos folata bio 206 µg ekvivalenata folata (eng. dietary folate equivalents-DFE), što je kudikamo manje od nacionalne preporuke koja navodi 400 µg DFE odnosno 200 µg folne kiseline. Prosječna vrijednost homocisteina iznosila je 9±2 µmol/L (raspon 5,42-13,90 µmol/L). Povećana vrijednost homocisteina (>10 µmol/L) utvrđena je u 34 % ispitanika. Može se zaključiti da osobe s celijakijom koje se pridržavaju bezglutenske prehrane, a sudjelovale su u ovom istraživanju, imaju mali unos folata i suboptimalan status folata i vitamina B12, vjerojatno zbog unosa folatom siromašnih bezglutenskih proizvoda. Stoga bi obogaćivanje ili dodatak folata u bezglutenske proizvode mogao povoljno utjecati na osobe s celijakijom, te predstavljati izazov prehrambenoj industriji

Thermal relaxation of magnetic clusters in amorphous Hf_{57}Fe_{43} alloy

The magnetization processes in binary magnetic/nonmagnetic amorphous alloy Hf_{57}Fe_{43} are investigated by the detailed measurements of magnetic hysteresis loops, temperature dependence of magnetization, relaxation of magnetization and magnetic ac susceptibility, including a nonlinear term. Blocking of magnetic moments at lower temperatures is accompanied with the slow relaxation of magnetization and magnetic hysteresis loops. All of the observed properties are explained with the superparamagnetic behaviour of the single domain magnetic clusters inside the nonmagnetic host, their blocking by the anisotropy barriers and thermal fluctuation over the barriers accompanied by relaxation of magnetization. From magnetic viscosity analysis based on thermal relaxation over the anisotropy barriers it is found out that magnetic clusters occupy the characteristic volume from 25 up to 200 nm3 . The validity of the superparamagnetic model of Hf_{57}Fe_{43} is based on the concentration of iron in the Hf_{100-x}Fe_{43} system that is just below the threshold for the long range magnetic ordering. This work throws more light on magnetic behaviour of other amorphous alloys, too

Esterase activity and isoenzymes in relation to morphogenesis in Mammillaria gracillis Pfeiff. tissue culture

Cactus Mammillaria gracillis Pfeiff. (Cactaceae), cultivated in vitro, spontaneously switches from an organised to unorganised way of growth, producing a habituated organogenic callus which regenerates normal and hyperhydric shoots without the addition of any growth regulators. Tumour tissues, induced by A. tumefaciens wild strain B6S3 (tumour TW) and rooty mutant GV3101 (tumour TR), do not express any organogenic potential. The esterase (arylesterase EC 3.1.1.2 and carboxylesterase EC 3.1.1.1) activity and isoenzyme pattern of morphologically different cactus tissues: shoot, callus, hyperhydric regenerant, tumours TW and TR, were compared. Tissue samples were frozen at –80 °C and lyophilized before protein extraction. Two esterase substrates, 1- and 2-naphthylacetate, were used. Esterase activity of all tissues varied during the period of one subculture. In shoots and tumours, the highest esterase activity for both substrates was measured on the 21st day, while in the callus and hyperhydric regenerants the highest activity was on the 7th day. Esterases were separated electrophoretically in polyacrylamide gradient gels under non-denaturating conditions. In total, 13 isoesterases, reacting with both substrates, were resolved. No differences in isoenzyme profile were noticed in correlation with the age of tissues, but the esterase activity varied among tissues. The significance of these results is discussed

Thermal relaxation and quantum tunnelling of the magnetization in Mn_12-acetate

The dependence of the magnetic moment m on the temperature T and the magnetic field H in a synthesized molecular magnet Mn_12-acetate has been measured using a SQUID magnetometer. The splitting of zero-field cooled (ZFC) and field-cooled (FC) m(T) curves below the so-called blocking temperature TB ( ≈ 3.6 K at H = 0) was observed. By measuring the time relaxation of m, it was found that it tended to the same value with the same relaxation time ( ≈ 560 s at 3 K) for both ZFC and FC processes. This indicates spin freezing below TB and the single molecule process in the explored temperature range (2 K < T < 4 K). The dependence of TB on applied H was also investigated. The decreasing of TB with increasing H can be explained in the frame of barrier reduction in the applied field