A comparative in vitro study of the carbon nanotubes on normal and cancer lung cells

Ugljenične nanocevi (UNC) imaju sve veću primenu u elektronici, kompjuterskoj i optičkoj industriji, kao i u biomedicini. Dok proizvodnja jednoslojnih UNC nanocevi beleži sve veći rast poslednjih godina, rizik koji nosi izlaganje ovom nanomaterijalu ostaje nerazjašnjen. Oskudni i često kontradiktorni podaci o toksičnim efektima jednoslojnih UNC ukazuju na potrebu za daljim ispitivanjima. U našim istraživanjima ispitivane su promene u ćelijskom odgovoru kao i morfološke promene nakon delovanja jednoslojnih ugljeničnih nanocevi na ćelijskoj liniji humanih fetalnih fibroblasta pluća MRC-5 i ćelijskoj liniji humanog adenokarcinoma pluća A549. U ovoj studiji korišćene su jednoslojne ugljenične nanocevi koje su sadržale rezidualne nečistoće poput gvožđa. Citotoksičnost jednoslojnih UNC (engl. single-walled carbon nanotubes – SWCNT) je ispitivana kolorimetrijskim MTT testom. Tokom 24 i 48h niske koncentracije jednoslojnih ugljeničnih nanocevi (<250 μg/mL) pokazale su nisku toksičnost na proliferaciju i vijabilnost u obe ispitivane ćelijske linije. Ipak, pri visokim koncentracijama UNC (250-750 μg/mL) antiproliferativni efekat je bio blizu IC50 vrednostima. Na osnovu rezultata dobijenih MTT testom može se zaključiti da su maligne A549 ćelije osetljivije na delovanje jednoslojnih UNC u odnosu na normalne MRC-5 ćelije. Kombinacija ugljeničnih nanocevi sa prirodnim polifenolima (resveratrolom i proantocijanidolima) nije značajno uticala na citotoksičnost u MRC-5 ćelijama, za razliku od A549 ćelija gde je tretman kombinacijama umanjio toksičnost ugljeničnih nanocevi. Transmisionom elektronskom mikroskopijom ispitivan je efekat jednoslojnih ugljeničnih nanocevi na ćelijsku morfologiju i preživljavanje. Intracelularni agregati ugljeničnih nanocevi primećeni su u obe ćelijske linije, čime je potvrđeno da ugljenične nanocevi ulaze u ćelije. Imajući u vidu da nanomaterijali poput ugljeničnih nanocevi indukuju oksidativni stres i njime posredovanu apoptozu, na protočnom citometru je određivano prisustvo ćelija u apoptozi i nekrozi. Tretman ćelija sa jednoslojnim ugljeničnim nanocevima nije doveo do značajnog porasta broja apoptotskih ili nekrotičnih ćelija, što ide u prilog niskoj toksičnosti ovog nanomaterijala, odnosno ukazuje na alternativne mehanizme toksičnosti. Međutim kombinacija jednoslojnih ugljeničnih nanocevi sa antioksidantima, resveratrolom i proantocijanidolima indukuje veći procenat apoptoze i nekroze u odnosu na tretman samo sa nanocevima. Promene u ekspresiji gena praćene su lančanom reakcijom polimeraza (PCR). Komparativna analiza rezultata genske ekspresije MRC-5 i A549 ćelija nakon tretmana sa jednoslojnim ugljeničnim nanocevima pojedinačno i u kombinaciji sa antioksidantima ukazala je na kompleksnost i raznolikost biološkog odgovora ispitivanih ćelija. U našem istraživanju ispitivana je i promena aktivnosti enzima antioksidativne zaštite i količine glutationa u ćeliji. Primena jednoslojnih ugljeničnih nanocevi u MRC-5 ćelijama dovodi po smanjenja specifične aktivnosti enzima SOD i GR, povećava specifičnu aktivnost GPx i ne utiče na promenu specifične aktivnosti GST i količine glutationa u ćeliji Primena jednoslojnih ugljeničnih nanocevi u A549 ćelijama dovodi po smanjenja specifične aktivnosti enzima SOD, ne utiče na promenu specifične aktivnost enzima GR, GST i GPx, i dovodi do povećanja količine glutationa u ćeliji. Ćelijska vijabilnost, morfološke promene, redoks homeostaza i ekspresija ispitivanih gena bile su promenjene nakon tretmana sa jednoslojnim ugljeničnim nanocevima. Iako su dobijeni rezultati značajni za procenu toksičnosti ugljeničnih nanocevi, neophodna su dalja istraživanja koja treba da doprinesu boljem razumevanju toksičnih efekata ugljeničnih nanocevi.Carbon nanotubes are being actively introduced in electronics, computer science, and optics as well as for various biomedical applications. While production of single-walled carbon nanotubes (SWCNT) has escalated in recent years, the knowledge on risk associated with exposure remains unclear. Contradictory data on the toxic effects of single-walled carbon nanotubes highlights the urgent need for further studies. In this study we investigated the alterations in cellular response along with morphological changes induced by single-walled carbon nanotubes in human lung fibroblast cell line MRC-5 and adenocarcinoma human alveolar basal epithelial cells A549. In this study we used SWCNT containing large amounts of residual metallic impurities such is iron, and the iron concentration increased in dose dependent manner in cells exposed to SWCNT. Cytotoxicity was evaluated by MTT assay and SWCNT showed little cytotoxic effect on the proliferation and viability of two cell lines tested at the concentrations used (<250 μg/mL) within 24 and 48h. However exposing both cell lines to high concentrations (250-750 μg/mL) resulted in near IC50 values. Based on MTT test SWCNT were more cytotoxic to A549 cell line. Cytotoxicity of SWCNT in combination with natural polyphenols (resveratrol and proanthocyanidins) did not noticeably affect the cytotoxicity of SWCNT to MRC-5 cells. However introduction of polyphenols did reduce the cytotoxicity of SWCNT to A549 cells. Transmission electron microscopy was used to complement cytotoxicity assays and to investigate the pathological effect of internalized SWCNT on cell morphology and survival. Intracellular bundles of CNTs, possibly aggregated/agglomerated were observed in both cell lines, confirming internalization after 24h exposure. Since nanoparticles like carbon nanotubes are toxic mainly because they cause oxidative stress, often associated with an increased apoptosis we checked for apoptotic and necrotic cells using flow cytometry. Incubation with SWCNT did not result in pronounced apoptosis or necrosis supporting its low toxicity and possibly alternative mechanism of cell damage. However incubation with SWCNT in combination with resveratrol and proanthocyanidins induced higher levels of both apoptosis and necrosis than SWCNT alone. Changes in gene expression following exposure to SWCNT were evaluated by polymerase chain reaction PCR array which indicated complex and diverse change in expression of genes involved in apoptosis, cell proliferation and oxidative stress. Finally we investigated the modulation of the antioxidant enzyme system and the changes in the cytosolic levels of GSH. SWCNT reduced the specific activity of SOD and GR enzymes, increased GPx activity. No changes in intracellular levels of GSH were observed in MRC-5 cell line. Same treatment in A549 cell reduced the specific activity of SOD, had no effect on GR, GST and GPx activity, but increased intracellular levels of GSH. Cell viability, morphologic changes, redox homeostasis and gene expression were affected by the presence of SWCNT. Although our findings are useful in predicting human response against SWCNT exposure, further study is needed for better understanding of the effects of SWCNT

A comparative in vitro study of the carbon nanotubes on normal and cancer lung cells

Ugljenične nanocevi (UNC) imaju sve veću primenu u elektronici, kompjuterskoj i optičkoj industriji, kao i u biomedicini. Dok proizvodnja jednoslojnih UNC nanocevi beleži sve veći rast poslednjih godina, rizik koji nosi izlaganje ovom nanomaterijalu ostaje nerazjašnjen. Oskudni i često kontradiktorni podaci o toksičnim efektima jednoslojnih UNC ukazuju na potrebu za daljim ispitivanjima. U našim istraživanjima ispitivane su promene u ćelijskom odgovoru kao i morfološke promene nakon delovanja jednoslojnih ugljeničnih nanocevi na ćelijskoj liniji humanih fetalnih fibroblasta pluća MRC-5 i ćelijskoj liniji humanog adenokarcinoma pluća A549. U ovoj studiji korišćene su jednoslojne ugljenične nanocevi koje su sadržale rezidualne nečistoće poput gvožđa. Citotoksičnost jednoslojnih UNC (engl. single-walled carbon nanotubes – SWCNT) je ispitivana kolorimetrijskim MTT testom. Tokom 24 i 48h niske koncentracije jednoslojnih ugljeničnih nanocevi (<250 μg/mL) pokazale su nisku toksičnost na proliferaciju i vijabilnost u obe ispitivane ćelijske linije. Ipak, pri visokim koncentracijama UNC (250-750 μg/mL) antiproliferativni efekat je bio blizu IC50 vrednostima. Na osnovu rezultata dobijenih MTT testom može se zaključiti da su maligne A549 ćelije osetljivije na delovanje jednoslojnih UNC u odnosu na normalne MRC-5 ćelije. Kombinacija ugljeničnih nanocevi sa prirodnim polifenolima (resveratrolom i proantocijanidolima) nije značajno uticala na citotoksičnost u MRC-5 ćelijama, za razliku od A549 ćelija gde je tretman kombinacijama umanjio toksičnost ugljeničnih nanocevi. Transmisionom elektronskom mikroskopijom ispitivan je efekat jednoslojnih ugljeničnih nanocevi na ćelijsku morfologiju i preživljavanje. Intracelularni agregati ugljeničnih nanocevi primećeni su u obe ćelijske linije, čime je potvrđeno da ugljenične nanocevi ulaze u ćelije. Imajući u vidu da nanomaterijali poput ugljeničnih nanocevi indukuju oksidativni stres i njime posredovanu apoptozu, na protočnom citometru je određivano prisustvo ćelija u apoptozi i nekrozi. Tretman ćelija sa jednoslojnim ugljeničnim nanocevima nije doveo do značajnog porasta broja apoptotskih ili nekrotičnih ćelija, što ide u prilog niskoj toksičnosti ovog nanomaterijala, odnosno ukazuje na alternativne mehanizme toksičnosti. Međutim kombinacija jednoslojnih ugljeničnih nanocevi sa antioksidantima, resveratrolom i proantocijanidolima indukuje veći procenat apoptoze i nekroze u odnosu na tretman samo sa nanocevima. Promene u ekspresiji gena praćene su lančanom reakcijom polimeraza (PCR). Komparativna analiza rezultata genske ekspresije MRC-5 i A549 ćelija nakon tretmana sa jednoslojnim ugljeničnim nanocevima pojedinačno i u kombinaciji sa antioksidantima ukazala je na kompleksnost i raznolikost biološkog odgovora ispitivanih ćelija. U našem istraživanju ispitivana je i promena aktivnosti enzima antioksidativne zaštite i količine glutationa u ćeliji. Primena jednoslojnih ugljeničnih nanocevi u MRC-5 ćelijama dovodi po smanjenja specifične aktivnosti enzima SOD i GR, povećava specifičnu aktivnost GPx i ne utiče na promenu specifične aktivnosti GST i količine glutationa u ćeliji Primena jednoslojnih ugljeničnih nanocevi u A549 ćelijama dovodi po smanjenja specifične aktivnosti enzima SOD, ne utiče na promenu specifične aktivnost enzima GR, GST i GPx, i dovodi do povećanja količine glutationa u ćeliji. Ćelijska vijabilnost, morfološke promene, redoks homeostaza i ekspresija ispitivanih gena bile su promenjene nakon tretmana sa jednoslojnim ugljeničnim nanocevima. Iako su dobijeni rezultati značajni za procenu toksičnosti ugljeničnih nanocevi, neophodna su dalja istraživanja koja treba da doprinesu boljem razumevanju toksičnih efekata ugljeničnih nanocevi.Carbon nanotubes are being actively introduced in electronics, computer science, and optics as well as for various biomedical applications. While production of single-walled carbon nanotubes (SWCNT) has escalated in recent years, the knowledge on risk associated with exposure remains unclear. Contradictory data on the toxic effects of single-walled carbon nanotubes highlights the urgent need for further studies. In this study we investigated the alterations in cellular response along with morphological changes induced by single-walled carbon nanotubes in human lung fibroblast cell line MRC-5 and adenocarcinoma human alveolar basal epithelial cells A549. In this study we used SWCNT containing large amounts of residual metallic impurities such is iron, and the iron concentration increased in dose dependent manner in cells exposed to SWCNT. Cytotoxicity was evaluated by MTT assay and SWCNT showed little cytotoxic effect on the proliferation and viability of two cell lines tested at the concentrations used (<250 μg/mL) within 24 and 48h. However exposing both cell lines to high concentrations (250-750 μg/mL) resulted in near IC50 values. Based on MTT test SWCNT were more cytotoxic to A549 cell line. Cytotoxicity of SWCNT in combination with natural polyphenols (resveratrol and proanthocyanidins) did not noticeably affect the cytotoxicity of SWCNT to MRC-5 cells. However introduction of polyphenols did reduce the cytotoxicity of SWCNT to A549 cells. Transmission electron microscopy was used to complement cytotoxicity assays and to investigate the pathological effect of internalized SWCNT on cell morphology and survival. Intracellular bundles of CNTs, possibly aggregated/agglomerated were observed in both cell lines, confirming internalization after 24h exposure. Since nanoparticles like carbon nanotubes are toxic mainly because they cause oxidative stress, often associated with an increased apoptosis we checked for apoptotic and necrotic cells using flow cytometry. Incubation with SWCNT did not result in pronounced apoptosis or necrosis supporting its low toxicity and possibly alternative mechanism of cell damage. However incubation with SWCNT in combination with resveratrol and proanthocyanidins induced higher levels of both apoptosis and necrosis than SWCNT alone. Changes in gene expression following exposure to SWCNT were evaluated by polymerase chain reaction PCR array which indicated complex and diverse change in expression of genes involved in apoptosis, cell proliferation and oxidative stress. Finally we investigated the modulation of the antioxidant enzyme system and the changes in the cytosolic levels of GSH. SWCNT reduced the specific activity of SOD and GR enzymes, increased GPx activity. No changes in intracellular levels of GSH were observed in MRC-5 cell line. Same treatment in A549 cell reduced the specific activity of SOD, had no effect on GR, GST and GPx activity, but increased intracellular levels of GSH. Cell viability, morphologic changes, redox homeostasis and gene expression were affected by the presence of SWCNT. Although our findings are useful in predicting human response against SWCNT exposure, further study is needed for better understanding of the effects of SWCNT

Modification of existing turboshaft engine in order to operate on synthetic gas

Sintetički gas je danas ko-proizvod procesa kao što su gasifikacija otpada i prerade biomase, uglja i drugih potencijalnih goriva. Iako sastav sintetičkog gasa zavisi od prethodnih procesa, generalno se sastoji od mešavine vodonika, ugljen-monoksida i metana u različitim odnosima. Ideja da se sintetički gas dobijen preradom otpada koristi kao gorivo za turbo-generator je veoma privlačna, ali i vrlo zahtevna. U ovom radu je prezentovana modifikacija postojećeg turbo-vratilnog motora da bi mogao da koristi sintetički gas kao gorivo. Pored problema kao što su mala toplotna moć, drugačiji stehiometrijski odnos u poređenju sa kerozinom i visok procenat vodonika, inženjerski zadatak je bio da se problem reši sa minimalnim brojem izmena. Problem je rešen modifikaciojom postojećih vazdušnih raspršivača i verifikovan je eksperimentalno.Synthetic gas is nowadays the co-product of procceses such as waste gasification and processing biomass, coal and other potentional fuels. Although its composition depends on previous process, synthetic gas is generally mixture of hydrogen, carbon-monoxide and methane in different ratios. The idea to use gases from waste as a fuel for gas-turbine generator producing electric energy is very attractive but also challenging. In this paper is presented modification of an existing turbo-shaft engine in order to be capable to operate with synthetic gas. Together with problems such as low heating value of the gas, different stochiometric ratio of gas and air compared to kerosene/air combination and high hydrogen contents, the engineering task was to do it with minimum number of changes. Problem is solved by adjusting existing airblast atomizers and experimentally verified

Modification of existing turboshaft engine in order to operate on synthetic gas

Sintetički gas je danas ko-proizvod procesa kao što su gasifikacija otpada i prerade biomase, uglja i drugih potencijalnih goriva. Iako sastav sintetičkog gasa zavisi od prethodnih procesa, generalno se sastoji od mešavine vodonika, ugljen-monoksida i metana u različitim odnosima. Ideja da se sintetički gas dobijen preradom otpada koristi kao gorivo za turbo-generator je veoma privlačna, ali i vrlo zahtevna. U ovom radu je prezentovana modifikacija postojećeg turbo-vratilnog motora da bi mogao da koristi sintetički gas kao gorivo. Pored problema kao što su mala toplotna moć, drugačiji stehiometrijski odnos u poređenju sa kerozinom i visok procenat vodonika, inženjerski zadatak je bio da se problem reši sa minimalnim brojem izmena. Problem je rešen modifikaciojom postojećih vazdušnih raspršivača i verifikovan je eksperimentalno.Synthetic gas is nowadays the co-product of procceses such as waste gasification and processing biomass, coal and other potentional fuels. Although its composition depends on previous process, synthetic gas is generally mixture of hydrogen, carbon-monoxide and methane in different ratios. The idea to use gases from waste as a fuel for gas-turbine generator producing electric energy is very attractive but also challenging. In this paper is presented modification of an existing turbo-shaft engine in order to be capable to operate with synthetic gas. Together with problems such as low heating value of the gas, different stochiometric ratio of gas and air compared to kerosene/air combination and high hydrogen contents, the engineering task was to do it with minimum number of changes. Problem is solved by adjusting existing airblast atomizers and experimentally verified

Contribution to research of spoiler and dome deflector TVC systems in rocket propulsion

Ustrojen je fizički model spojlera i kupolastog deflektora u sustavu upravljanja vektorom potiska (UVP) razmatrajući zaključke prethodnih i sadašnjih ispitivanja. Prema logici fizičkog modela razvijen je matematički model. Algoritam modela i rezultati su analizirani i objašnjeni. Konačno, rezultati modela su potvrđeni testovima realnog motora.Physical model of spoiler and dome deflector thrust vector control (TVC) system was established considering previous and current research observations. According to logic of physical model an engineering mathematical model is derived. Model algorithm and results were analysed and explained. Finally, model data were confirmed with real motor tests

A novel 6 DOF thrust vector control test stand

U ovom radu se predlaže inovativnu konstrukciju ispitnog stola za precizno mjerenje vektora potiska raketnog motora tijekom njegovog rada. Jasno je izložena konstrukcija ispitnog stola kao i procedure te matematički model za kalibraciju ispitnog stola. Metoda obrade podataka dobivenih ispitivanjem kao i rezultati ispitivanja "jet tab" sustava za upravljanje vektorom potiska detaljno su prezentirani. Eksperimenti su pokazali da je ispitni stol iznimno funkcionalan, a da dobineni rezultati imaju odličnu ponovljivost i poklapanje s rezultatima autora koji su koristili ispitne stolove drugačije konstrukcije za mjerenje istog ili sličnog mehanizma za upravljanje vektorom potiska.This study proposes an innovative test stand design to accurately measure rocket motor thrust vector during its operation. Test stand design is clearly presented as well as procedure and mathematical model for its calibration. A method of processing data obtained from the experiments and the results of the jet tab system for thrust vector control are presented in detail. Experiments have shown that the test stand is highly functional and the results obtained have excellent repeatability and matching with the results of the other authors who have used different construction test stands for measurement of the same or a similar mechanism for thrust vector control

Hypolipidemic and antioxidant effects of buckwheat leaf and flower mixture in hyperlipidemic rats

As a source of biologically active compounds, buckwheat has beneficial effects in nutrition due to its high content of flavonoids, particularly rutin. Aim of our study was to examine effects of buckwheat on plasma lipid status and phospholipids fatty acids composition, histological and parameters of oxidative stress in Wistar rats fed a high-fat diet. This study showed that buckwheat leaf and flower (BLF) mixture supplementation significantly reduce weight gain, plasma lipid concentrations and atherogenic index in rats fed a high-fat diet. Treatment of the high-fat group of animals with buckwheat significantly increased percentage of n-6 fatty acids as well as eicosapentaenoic acid (EPA) and decreased percentage of saturated fatty acids (SPA) and oleic acid. Buckwheat antioxidant effects diminished negative influence of high-fat diet in hyperlipidemic rats, while pathohistological analysis of liver confirmed changes after high-fat consumption. Our results showed hypolipidemic, antiatherogenic and antioxidative features of buckwheat leaf and flower mixture, and these parts of the plant with the highest rutin content could be beneficial in prevention and curing of hyperlipidemia

Microbiological quality of probiotic products

Microorganisms used as probiotics should meet elementary safety aspects (non-toxicity, absence of antibiotic resistance genes and translocation) and functional/technological aspects (resistance and survival in the acid gastric environment, adhesiveness, stability, and cell viability). Probiotics with the health claim of being a dietary product or a pharmabiotic (drug category) should be clinically tested, validated, documented, and continuously controlled for quality. Important quality parameters include the identification of declared probiotic strains, the number of viable microorganisms (probiotic bacteria and/or fungi), and microbiological purity (absence of specified pathogenic/opportunistic pathogenic bacteria and fungi, and limitation of total unspecified contaminants such as aerobic bacteria, yeasts, and molds). Due to numerous reports of low-quality commercial probiotics marketed for human use, this review discusses the methods used to test the probiotic microorganism content, safety for the intended use, and proven health benefits of those probiotics whose microbiological quality deviates from the manufacturer's stated content, as well as the maintenance of cell viability, i.e., stability of the probiotic during the shelf life. In addition, the adverse effects of probiotics and the potential hazards to the health of the user are addressed

Study of innovative subsonic ramjet

Subsonic ramjets, due to its simplicity, nowadays could be very attractive for expendable unmanned applications. However, due to very low efficiency at low Mach numbers, practically there isn’t any important application at subsonic speed. In 50’s subsonic ramjet was used for tip jet applications. Later in 70’s there was a study of Fan Augmented Ramjet (FARJ) where a fan was in-tended to be powered by a piston engine, both in subsonic and supersonic regimes. Almost at the same time it was analyzed ejector augmented subsonic ramjet. Both of these studies did not find real application of such engines. Finally, there was an attempt for the use of an Electric Ducted Fan, used in RC models, with a combustor but exit fan pressure was almost at atmospheric pressure which results in very low efficiency. This paper presents a study of propulsion system which consists of a pitot intake, electrically powered compressor/fan, combustor and nozzle (Electrically Fan Augmented Ram Jet, EFARJ). The electric motor connection to the compressor/fan is direct, without gearbox, which implies usage of a high-speed brushless motor. Such propulsion system is compared to pure ramjet and finally it is compared to performances of small expendable turbojet. Comparison is made regarding costs, weight and thrust/consumption. The study shows that the proposed propulsion system could be competitive for expendable, low speed and short duration applications