31 research outputs found

    Model of Autonomous House as Contribution to Sustainable Development of Istria

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    U radu se obrađuju razlozi i koncept gradnje autonomnih kuća u Istri, te način koriÅ”tenja energije i materijalnih resursa. PojaÅ”njava se princip samostalne izrade fotonaponskih sustava i solarnih kolektora na kroviÅ”tu kuće, sakupljanje vode i njezino skladiÅ”tenje uz opis primjer vlastite izrade calabash sustava kao cisterne za vodu, sustav kućne odvodnje i kompostiranje biorazgradivog otpada. Analizira se industrijska konoplja kao moguć građevinski materijal, pojaÅ”njava se armiranje, izrada kompozita i izolacije od iste. Kod razrade kuća od bala sijena obrazlažu se njihove prednosti i jednostavnost izgradnje. Opisuju se klimatske vrijednosti Istre koje pogoduju izradu autonomnih kuća, te predlaže integriranje sadržaja o gradnji autonomne kuće u nastavu tehničke kulture.The paper analyses the reasons and concept of autonomous houses in Istria as well as the method of energy and material resources use. Elaborated is the principle of producing self-made photovoltaic system and solar collectors on the roof of the house, collecting and storage of water explained on an example of individual calabash system water tank, home wastewater system and composting of biodegradable waste. Analysis is made of industrial hemp as possible building material, explaining the reinforcement, composite making and insulation thereof. In elaborating hay bales house, the advantages and simplicity of construction are pointed out. Climate features of Istria are described which favour the deployment of autonomous houses, and integration of subject matter on autonomous houses into technical culture syllabus is proposed

    The importance of cross-reactivity in grass pollen allergy

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    According to the data obtained from in vivo and in vitro testing in Serbia, a significant number of patients have allergic symptoms caused by grass pollen. We examined the protein composition of grass pollens (Dactylis glomerata, Lolium perenne and Phleum pratense) and cross-reactivity in patients allergic to grass pollen from our region. The grass pollen allergen extract was characterized by SDS-PAGE, while cross-reactivity of single grass pollens was revealed by immunoblot analysis. A high degree of cross-reactivity was demonstrated for all three single pollens in the sera of allergic patients compared to the grass pollen extract mixture. Confirmation of the existence of cross-reactivity between different antigenic sources facilitates the use of monovalent vaccines, which are easier to standardize and at the same time prevent further sensitization of patients and reduces adverse reactions

    Anti-biofilm Properties of Bacterial Di-Rhamnolipids and Their Semi-Synthetic Amide Derivatives

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    A new strain, namely Lysinibacillus sp. BV152.1 was isolated from the rhizosphere of ground ivy (Glechoma hederacea L.) producing metabolites with potent ability to inhibit biofilm formation of an important human pathogens Pseudomonas aeruginosa PAO1, Staphylococcus aureus, and Serratia marcescens. Structural characterization revealed di-rhamnolipids mixture containing rhamnose (Rha)-Rha-C10-C10, Rha-Rha-C8-C10, and Rha-Rha-C10-C12 in the ratio 7: 2: 1 as the active principle. Purified di-rhamnolipids, as well as commercially available di-rhamnolipids (Rha-Rha-C10-C10, 93%) were used as the substrate for the chemical derivatization for the first time, yielding three semisynthetic amide derivatives, benzyl-, piperidine-, and morpholine. A comparative study of the anti-biofilm, antibacterial and cytotoxic properties revealed that di-Rha from Lysinibacillus sp. BV152.1 were more potent in biofilm inhibition, both cell adhesion and biofilm maturation, than commercial di-rhamnolipids inhibiting 50% of P. aeruginosa PAO1 biofilm formation at 50 mu g mL(-1) and 75 mu g mL(-1), respectively. None of the dirhamnolipids exhibited antimicrobial properties at concentrations of up to 500 mu g mL(-1). Amide derivatization improved inhibition of biofilm formation and dispersion activities of di-rhamnolipids from both sources, with morpholine derivative being the most active causing more than 80% biofilm inhibition at concentrations 100 mu g mL(-1). Semisynthetic amide derivatives showed increased antibacterial activity against S. aureus, and also showed higher cytotoxicity. Therefore, described di-rhamnolipids are potent anti-biofilm agents and the described approach can be seen as viable approach in reaching new rhamnolipid based derivatives with tailored biological properties

    LOAD MODELLING AT LOW VOLTAGE USING CONTINUOUS MEASUREMENTS

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    The paper presents the results of load modelling at low voltage level of transformer station (TS) 10/0.4 kV/kV supplying predominantly residential load. Necessary data are obtained from recording device and measuring information system for continuous measurements permanently installed in concerned distribution network. Identified parameters of static exponential load model are classified according to day periods and days of the week, and statistically analysed in order to obtain reliable parameter estimates. These are compared with literature data for the same, residential load class. Possibilities for further application of described load modelling procedure are listed

    Prevention of polymicrobial biofilms composed of Pseudomonas aeruginosa and pathogenic fungi by essential oils from selected Citrus species

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    Mixed microbial infections caused by Pseudomonas aeruginosa and pathogenic fungi are commonly found in patients with chronic infections and constitute a significant health care burden. The aim of this study was to address the potential polymicrobial antibiofilm activity of pompia and grapefruit essential oils (EOs). The mechanism of antimicrobial activity of EOs was analysed. EOs of pompia and grapefruit inhibited fungal growth with MIC concentrations between 50 and 250 mg L-1, whereas no effect on P. aeruginosa growth was observed. Both citrus EOs inhibited formation of bacterial and fungal monomicrobial biofilms in concentrations of 50 mg L-1 and were efficient in potentiating the activity of clinically used antimicrobials in vitro. The concentration of 10 mg L-1 EOs inhibited mixed biofilm formation composed of P. aeruginosa and Aspergillus fumigatus or Scedosporium apiospermum. Citrus EOs affected quorum sensing in P. aeruginosa and caused fast permeabilisation of Candida albicans membrane. Pompia and grapefruit EOs potently inhibited biofilm formation and could be used for the control of common polymicrobial infections

    Supplementary data for article: Aleksić, I.; Å egan, S.; Andrić, F.; Zlatović, M.; Moric, I.; Opsenica, D. M.; Senerovic, L. Long-Chain 4-Aminoquinolines as Quorum Sensing Inhibitors in Serratia Marcescens and Pseudomonas Aeruginosa. ACS Chemical Biology 2017, 12 (5), 1425ā€“1434. https://doi.org/10.1021/acschembio.6b01149

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    Supporting information for: [https://doi.org/10.1021/acschembio.6b01149]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2461]Related to accepted version: [http://cherry.chem.bg.ac.rs/handle/123456789/3089

    Anti-quorum sensing activity, toxicity in zebrafish (Danio rerio) embryos and phytochemical characterization of Trapa natans leaf extracts

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    Ethnopharmacological relevance: Trapa natans L. (water chestnut or water caltrop) is a widespread aquatic plant, which has been cultivated for food and traditional medicine since ancient times. Pharmacological studies showed that water chestnut exhibits the wide range of biological activities, such as antimicrobial, antioxidative, analgesic, anti-inflammatory, as well as antiulcer. Aim of the study: Evaluation of anti-virulence potential and toxicity of T. natans methanol (TnM), acetone (TnA) and ethyl acetate (TnEA) leaf extracts. Materials and methods: The anti-quorum sensing activity of Tn extracts was addressed by measuring their effects on biofilm formation, swarming motility and pyocyanin and elastase production in Pseudomonas aeruginosa. Specific P. aeruginosa biosensors were used to identify which of the signaling pathways were affected. The lethal and developmental toxicity of extracts were addressed in vivo using the zebrafish (Danio rerio) model system. The phenolic composition of T. natans leafs extracts was analyzed by a linear ion trap-OrbiTrap hybrid mass spectrometer (LTQ OrbiTrapMS) and UHPLC system configured with a diode array detector (DAD) hyphenated with the triple quadrupole mass spectrometer. Results: Subinhibitory concentrations of Tn leaf extracts (0.2 MIC) inhibited pyocyanin and elastase production up to 50% and 60%, respectively, and reduced swarming zones, comparing to non-treated P. aeruginosa. TnA inhibited biofilm formation by 15%, TnM showed a stimulatory effect on biofilm formation up to 20%, while TnEA showed no effect. The bioactive concentrations of TnM and TnA were not toxic in the zebrafish model system. Twenty-two phenolic compounds were tentatively identified in TnM, where thirteen of them were identified in T. natans for the first time. Tn extracts, as well as their major components, ellagic and ferulic acids, demonstrated the ability to interfere with P. aeruginosa Las and PQS signaling pathways. Conclusions: This study demonstrates anti-virulence potential of Tn leaf extracts against medically important pathogen P. aeruginosa and confirms the ethnopharmacological application of this plant against microbial infections.Related to published version: [https://imagine.imgge.bg.ac.rs/handle/123456789/1111]This is the peer reviewed version of the paper: Aleksić, I., Ristivojević, P., Pavić, A., Radojević, I., Comić, L. R., Vasiljević, B., Opsenica, D., Milojkovic-Opsenica, D., & Å enerović, L. (2018). Anti-quorum sensing activity, toxicity in zebrafish (Danio rerio) embryos and phytochemical characterization of Trapa natans leaf extracts. Journal of Ethnopharmacology, 222, 148ā€“158. [https://doi.org/10.1016/j.jep.2018.05.005]Supplementary data: [https://imagine.imgge.bg.ac.rs/handle/123456789/1768

    Fullerenol nanoparticles as a new delivery system for doxorubicin

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    Doxorubicin is a very potent chemotherapeutic drug, however its side effects limit its clinical use. The aim of this research was to investigate the properties of a fullerenol/doxorubicin nanocomposite, its potentially cytotoxic and genotoxic effects on malignant cell lines, as well as its toxicity towards zebra fish embryos. Chromatographic, NMR and mass spectral analysis of the nanocomposite imply that interactions between doxorubicin and fullerenol are non-covalent bonds. The stability of the nanocomposite was confirmed by the use of atomic force microscopy, dynamic light scattering and transmission electron microscopy. The nanocomposite, compared to the free doxorubicin at equivalent concentrations, significantly decreased the viability of MCF-7 and MDA-MB-231 cells. The flow cytometry results indicated that doxorubicin-loaded fullerenol could remarkably increase the uptake of doxorubicin suggesting that fullerenol might be a promising intracellular targeting carrier for the efficient delivery of antitumor drugs into tumor cells. The nanocomposite also affected cell cycle distribution. A genotoxicity test showed that the nanocomposite at all examined concentrations on MCF-7 and at lower concentrations on MDA-MB-231 cells caused DNA damage. Consequently, cell proliferation was notably reduced when compared with controls. Results of the zebrafish embryotoxicity assay showed a decreased overall toxicity, particularly cardiotoxicity and increased safety of the nanocomposite in comparison to doxorubicin alone, as manifested by a higher survival of embryos and less pericardial edema

    Matrix Metalloproteinase-9 and Tissue Inhibitor of Matrix Metalloproteinase-1 in Sepsis after Major Abdominal Surgery

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    Background. The role of matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) in sepsis after major abdominal surgery and sepsis-associated organ dysfunction is unexplored. Materials and Methods. Fifty-three patients with sepsis after major abdominal surgery were compared to 50 operated and 50 nonoperated controls. MMP-9, TIMP-1, biomarkers of inflammation, kidney and liver injury, coagulation, and metabolic disorders were measured daily during 96 h following diagnosis of sepsis and once in controls. MMP-9/TIMP-1 ratios and disease severity scores were calculated. Use of vasopressors/inotropes, mechanical ventilation, and survival were recorded. Results. Septic patients had lower MMP-9 and MMP-9/TIMP-1 ratios but higher TIMP-1 levels compared to controls. AUC-ROC for diagnosis of sepsis was 0.940 and 0.854 for TIMP-1 and 0.924 and 0.788 for MMP-9/TIMP-1 ratio (sepsis versus nonoperated and sepsis versus operated controls, resp.). Lower MMP-9 and MMP-9/TIMP-1 ratio and higher TIMP-1 levels were associated with shorter survival. MMP-9, TIMP-1, and MMP-9/TIMP-1 ratio correlated with biomarkers of inflammation, kidney and liver injury, coagulation, metabolic disorders, and disease severity scores. Use of vasopressors/inotropes was associated with higher TIMP-1 levels. Conclusions. MMP-9, TIMP-1, and MMP-9/TIMP ratio were good diagnostic or prognostic biomarkers of sepsis after major abdominal surgery and were linked to sepsis-associated organ dysfunction
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