Vezivanje glikozilfosfatidilinozitola(GPI-a) za membranske proteine eritrocita pod dejstvom insulina

In this work GPI binding to membrane proteins from erythrocytes of insulinoma patients for whom prolonged hyperinsulinism and hypoglycemia were characteristic, as well as from normal erythrocytes incubated with supraphysiological concentrations of insulin were analyzed. In the RBCs from insulinoma patients, covalent GPI binding to red cell membrane proteins in the spectrin/ankyrin region, band 4.1 and two proteins of molecular mass of 115 and 110 kD was demonstrated. In erythrocytes incubated with insulin label was associated with band 4.1 and two proteins of molecular mass of 115 and 110 kD. Extraction studies showed that the 100-kD proteins are unrelated to band 3 since they were found in Triton- prepared cytoskeleton. To our knowledge this is the first demonstration of such a modification of red cell skeletal proteins, and the first demonstration of post-translation GPI binding to red cell skeletal proteins in response to insulin. A mechanism proposed for GPI binding to red cell skeletal proteins as well as the relevance of these results for physiological disorders that are characterized by hyperinsulinism are briefly discussed.U ovom radu ispitivano je vezivanje GPI-a za membranske proteine eritrocita pacijenata obolelih od insulinoma, za koje su karakteristični dugotrajni hiperinsulinizam i hipoglikemija, kao i u normalnim eritrocitima inkubiranim sa suprafiziološkim koncentracijama insulina. Nađeno je da u eritrocitima pacijenata dolazi do kovalentnog vezivanja GPI-a za membranske proteine eritrocita i to u oblasti spektrina i ankirina, za traku 4.1. i dva proteina molekulskih masa 115 i 110kD. U eritrocitima inkubiranim sa insulinom GPI se vezuje za traku 4.1. i dva proteina molekulskih masa 115 i 110 kD. Utvrđeno je da proteini mase 100 kD ne potiču od trake 3, jer su detektovani u citoskeletnoj frakciji zaostaloj posle ekstrakcije membranskih proteina rastvorom Triton-a. U ovom radu je prvi puta detektovana modifikacija citoskeletnih proteina eritrocita vezivanjem GPI-a, kao i post-translaciono vezivanje GPI-a za citoskeletne proteine eritrocita pod uticajem insulina. Ukratko je diskutovan mehanizam vezivanja GPI-a za proteine citoskeleta eritrocita, kao i značaj dobijenih rezultata za razumevanje fizioloških poremećaja u hiperinsulinizmu

Influence of pumpkin seed oil in continuous phase on droplet size and stability of water-in-oil emulsions

The aim of this work was to contribute to the optimized production of water-in-oil emulsions with pumpkin seed oil in the oil phase using a high-speed homogenizer. Pumpkin seed oil is a valuable natural source of essential fatty acids and biologically active micronutrients that contribute to its nutritive value and medical uses, and reduce interfacial tension between water and the oil phases. Therefore, pumpkin seed oil can be considered as a prosperous oil phase whose use can possibly decrease the amount of some emulsifier that is normally involved in every emulsification process. A central composite rotatable experimental design was implemented to analyze the impact of the contents of polyglycerol polyricinoleate and pumpkin seed oil in the continuous phase, as well as water phase content in the emulsion on droplet size distribution and the response surface methodology was used to obtain optimal conditions for water-in-oil emulsion preparation. Mean size diameter of water droplets was in a range from 400 to 850 nm, with mean peak width of 100 to 220 nm, respectively. The influence of all three investigated factors on the emulsification was determined. Additionally, the emulsions prepared with pumpkin seed oil showed a higher stability during the storage time compared to the emulsions with sunflower oil

Impact of Microstructure on Humidity Influence on Complex Impedance of Iron Manganite

This work deals with our continued research of oxide materials for potential application in gas/humidity sensing. We have made thick film samples using iron manganite powder synthesized by a sol-gel combustion method with a net-like structure, by screen printing on alumina substrate with PdAg interdigitated electrodes. The thick film samples were fired at two temperatures 600 and 800°C. The powder morphology was retained and only the organic compounds in the paste were burnt-out at 600°C, while at 800°C the thick film surface morphology was different where grain growth and individual particles can be observed. We measured complex impedance in a temperature and humidity chamber at room temperature (25°C) in the relative humidity range 30 – 90 % and frequency 100 Hz - 1 MHz. The thick film surface morphology has a significant influence on the effect of humidity on complex impedance. The complex impedance of thick films fired at 600°C was high and did not decrease noticeably with increase in relative humidity (RH), except for RH 80 and 90%, while thick film samples fired at 800°C had an overall lower impedance that reduced more noticeably with increase in RH 40–70% and even more for RH 80 and 90%.This is the peer-reviewed version of the paper:Nikolic, M.V., Vasiljević, Z.Z., Dojčinović, M.P., Vujančević, J., Radovanović, M., 2020. Impact of Microstructure on Humidity Influence on Complex Impedance of Iron Manganite, in: 2020 43rd International Spring Seminar on Electronics Technology (ISSE). Presented at the 2020 43rd International Spring Seminar on Electronics Technology(ISSE), IEEE. [https://doi.org/10.1109/ISSE49702.2020.9120967]Published version: [https://hdl.handle.net/21.15107/rcub_dais_10026

Synthesis and application of silica particles for the removal of heavy metals and pesticide residues from aqueous solutions

In this study, the adsorption behavior of silica adsorbents with different morphology and porosity has been examined in order to evaluate their use for the purification of wastewaters containing toxic environmental chemicals such as heavy metals and pesticide residues. Three different types of silica particles were investigated: (i) microporous silica core particles prepared by the hydrolysis and condensation of tetraethylorthosilicate (TEOS), (ii) mesoporous silica particles generated by the neutralization of highly basic sodium silicate solution and (iii) silica core-shell particles composed of mesoporous silica layers around dense cores. Monodispersed spherical silica particles produced from TEOS have a microporous structure but the lowest adsorption efficiency and adsorption capacity of both heavy metals and pesticides. Polydispersed silica particles of irregular shape prepared from highly basic sodium silicate solution exhibit a mesoporous structure and high efficiency for the removal of heavy metals and pesticides from aqueous solutions. Monodispersed core-shell particles composed of a microporous core and a mesoporous shell also have high adsorption efficiencies in both combinations. Moreover, silica particles can be easily functionalized with ferrite nanoparticles, which allow the magnetic separation of silica adsorbents from aqueous solutions

Da li holesterol vezan za hemoglobin utiče na anti-oksidativni enzimski sistem u humanim eritrocitima?

In a previous study, it was shown that the lipid fraction, which is occasionally observed in red blood cell hemolysates, represents cholesterol (Ch) associated with phospholipid firmly bound to haemoglobin (termed Hb-Ch). The current study was conducted to investigate whether Hb-Ch could affect the primary anti-oxidant enzyme defence system in human erythrocytes. Sixty healthy volunteers were used for the current study. Group 1 consisted of 28 subjects without or with a low level of Hb-Ch. Group 2 comprised 32 subjects with a considerably higher level of Hb-Ch. The activities of erythrocyte superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase, as well as the content of methaemoglobin (metHb) were measured in both groups. The results indicated that the amount of Hb-Ch neither influenced the activities of the erythrocyte anti-oxidant enzymes nor altered the level of metHb. However, a higher amount of Hb-Ch changed the correlations in the part of the anti-oxidant defence system relating to glutathione, suggesting increased peroxidative pressure from plasma lipids. Group 2 also had significantly increased concentrations of total plasma Ch and triglycerides. Together, these facts are strong indications that the anti-oxidant defence system in human erythrocytes finely retunes its composition according to plasma oxidative demands.U prethodnom radu pokazano je da lipidna frakcija koja se javlja u hemolizatu zdravih ljudi predstavlja holesterol (asosovan sa fosfolipidima) čvrsto vezan za hemoglobin (Hb-Ch). U ovom radu ispitivan je uticaj Hb-Ch na anti-oksidativni enzimski sistem u humanim eritrocitima. Određena je aktivnost superoksid-dizmutaze, katalaze, glutation-peroksidaze i glutation-reduktaze, kao i sadržaj met-hemoglobina (metHb) u eritrocitima 60 ljudi, podeljenih u dve grupe na osnovu količine Hb-Ch. Rezultati pokazuju da količina prisutnog Hb-Ch ne menja aktivnost merenih enzima, niti nivo metHb. Međutim, u grupi ispitanika sa povećanim sadržajem Hb-Ch zapažene su korelativne promene u delu anti-oksidativnog enzimskog sistema povezanog sa glutationom. U istoj grupi detektovane su i veće koncentracije ukupnog holesterola i triglicerida u plazmi, što zajedno ukazuje na povećani peroksidativni pritisak iz plazme. Ovi rezultati ukazuju da odbrambeni anti-oksidativni enzimski sistem u humanim eritrocitima prilagođava svoju organizaciju prema zahtevima iz svog okruženja.

TRANSPORT IN HELICALLY COILED CARBON NANOTUBES: SEMICLASSICAL APPROACH

Semiconducting single wall carbon nanotubes (SWCNTs) exhibit high electron mobility in low electric field. Tube diameter and temperature have been found to strongly affect transport properties of SWCNTs. We have investigated electron mobility of helically coiled carbon nanotubes (HCCNTs). Electron and phonon band structures of HCCNTs are used in calculation of electron-phonon matrix elements. Scattering rates are calculated using the first order perturbation theory while taking care of energy and momentum conservation law. In order to obtain electron drift velocities, steady state simulation of charge transport is performed using Monte Carlo method.Semiconducting single wall carbon nanotubes (SWCNTs) exhibit high electron mobility in low electric field. Tube diameter and temperature have been found to strongly affect transport properties of SWCNTs. We have investigated electron mobility of helically coiled carbon nanotubes (HCCNTs). Electron and phonon band structures of HCCNTs are used in calculation of electron-phonon matrix elements. Scattering rates are calculated using the first order perturbation theory while taking care of energy and momentum conservation law. In order to obtain electron drift velocities, steady state simulation of charge transport is performed using Monte Carlo method

Cleaning and Desinfection a Part of Water Suplly System Ušće Zemun – Piramida New Belgrade

Globalno zagrevanje i porast prosečne temperature doveli su do pojave cijanobakterija posebno u stajaćim vodama. Posebnu opasnost za zdravlje su toksini koje ove bakterije proizvode usled neadakvatnog tretmana. Razni toksini mogu izazvati osip na koži, mogu dovesti do raka jetre, a neki od njih su jaki neurotoksini. Iz ovih razloga neophodno je da se cijanobakterije uklone pre nego dodju u pogon finalne prerade vode. Rezultati laboratorijskih ispitivanja na cijanobakterije posle tretmana cevovoda sprovedeni u Zavodu za javno zdravlje Srbije i laboratorija JKP Beogradski vodovod pokazali su posle izvršenih procesa čišćenja, pranja i dezinfekcije znacajno smanjenje broja cijanobakterija. Pokazano je da je KMnO4 efikasno sredstvo za suzbijanje cijanobakterija u koncentraciji do 25 mg/l.It was noticed worldwide that nutrient enrichment and climatic change as global warming and hydrologic changes with periods of more intense droughts strongly affect cyanobacterial growth. Toxigenic cyanobacteria that can produce a wide range of cyanotoxins (hepato-, neuro-, dermatotoxins) are one of the major health risks humans and animals are exposed to via drinking water. Therefore, it is important to remove the cyanobacteria before the water comes to a plant for a final treatment. Results of laboratory examination carried out by National Public Health Institution of Serbia and Belgrade Waterworks and Sewerage shows significant reduction of number of cyanobacteria aftre our treatment with KMnO4. The efficiency of the treament is the highest when concentration of KMnO4 was 25 mg/l

Humidity sensing properties of nanocrystalline pseudobrookite (Fe2TiO5) based thick films

Pseudobrookite based nanopowder was obtained by solid state synthesis of starting hematite and anatase nanopowders in the weight ratio 55:45. Structural and morphological properties were analyzed using X-ray diffraction (XRD), BET, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, UV/Vis diffuse reflectance spectroscopy, Field emission scanning electron microscopy (FESEM) and Transmission electron microscopy (TEM) confirming the formation of nanocrystalline pseudobrookite. The obtained powder was mixed with a binder (ethyl cellulose), dispersant (alpha-terpinol) and adhesion agents (acetic acid and distilled water) to obtain a thick film paste. It was screen printed on alumina substrate with interdigitated PdAg electrodes and fired at 600 degrees C for 30 min. Formation of a porous nanocrystalline thick film structure was shown using Scanning electron microscopy (SEM), while Hall measurements enabled determination of carrier mobility. Change of impedance response in the frequency range 42 Hz-1 MHz with humidity was analyzed at room temperature (25 degrees C) and 50 degrees C in the relative humidity range 30-90% and 40-90%, respectively. At 42 Hz, and room temperature the impedance reduced similar to 28 times, while at 50 degrees C it reduced similar to 147 times in the relative humidity range 40-90%. The sensor showed rapid response (16 s) and relatively low hysteresis (8.39% at 25 degrees C and 2.64% at 50 degrees C) showing that this is a promising material for application in humidity sensing

Trichoderma spp. from Pine Bark and Pine Bark Extracts: Potent Biocontrol Agents against Botryosphaeriaceae

Pinus sylvestris bark represents a rich source of active compounds with antifungal, antibacterial, and antioxidant properties. The current study aimed to evaluate the antifungal potential of P. sylvestris bark against Botryosphaeria dothidea, Dothiorella sarmentorum, and Neofusicoccum parvum (Botryosphaeriaceae) through its chemical (water extracts) and biological (Trichoderma spp. isolated from the bark) components. The water bark extracts were prepared at two temperatures (80 and 120 °C) and pH regimes (7 and 9). The presence of bark extracts (30%) caused inhibition of mycelial growth of B. dothidea and D. sarmentorum for 39 to 44% and 53 to 60%, respectively. Moreover, we studied the antagonistic effect of three Trichoderma isolates originating from the pine bark. Trichoderma spp. reduced growth of B. dothidea by 67%–85%, D. sarmentorum by 63%–75% and N. parvum by 55%–62%. Microscopic examination confirmed typical mycoparasitism manifestations (coiling, parallel growth, hook-like structures). The isolates produced cellulase, β-glucosidase and N-acetyl-β-glucosaminidase. The volatile blend detected the emission of several volatile compounds with antimicrobial activity, including nonanoic acid, cubenene, cis-α-bergamotene, hexanedioic acid, and verticillol. The present study confirmed in vitro potential of P. sylvestris bark extracts and Trichoderma spp. against the Botryosphaeriaceae. The study is an important step towards the use of environmentally friendly methods of Botryosphaeriaceae disease control