Načini upravljanja procesom fermentacije u siliranim hranivima

The control of fermentation process in ensilaged livestock feed is based on the knowledge of biomasses. The important aspects are the suitability for ensilaging (the content of fermentative carbohydrates and buffer capacity of the biomass), providing of the correct level of dry matter and anaerobic environment, wilting, using the chemical additives such as organic acids and their salts, using of biologic additives (inoculants), adsorption of mycotoxins, etc. In purpose of making the process of ensilaging of grasses, legumes and grass-legume mixes, the silages are prepared as bales or silo-tubes.Kontrola procesa fementacije bazira se na poznavanju biomasa u pogledu pogodnosti za siliranje, odnosno obezbeđivanju povoljnog odnosa šećera i pufernog kapaciteta. Biomase višegodišnjih leguminoza i trava neophodno je provenjavati, odnosno povećati sadržaj suve materije u silomasi na najmanje 300-400 g kg-1. Za teško silirajuće biomase (višegodišnje i jednogodišnje leguminoze) koristiti ugljenohidratna hraniva (kukuruzna prekrupa, prekrupa ostalih žitarica, suvi rezanci šećerne repe, melasa, i dr.). Korišćenje hemijskih sredstava iz reda organskih kiselina i njihovih soli. Upotreba bioloških dodataka, inokulanata u smeši sa enzimima (amilaze, celulaze, hemicelulaze i dr.) obezbeđuje dobijanje dobre i stabilne silaže, kao i silaže veće hranljive vrednosti. Korišćenje inokulanata sa homo i heterotrofnim mikroorganizmima u cilju obezbeđivanja aerobne stabilnosti silaža, posebno lakosilirajućih biomasa (kukuruza, sirka, sudanske trave, italijanskog ljulja i dr.)

One-pot synthesis of biocompatible NaYF4:Yb,Er nanoparticles for cell labeling

In modern medical research, great attention has been focused to the development of the new biomarkers which include up-converting nanoparticles (UCNPs). Their optical response is triggered by NIR radiation that achieves deeper tissue penetration when compared with traditionally used fluorophores. In this work, biocompatible NaYF4: Yb, Er nanoparticles were synthesized by polymer assisted one-pot solvothermal processing using chitosan or poly(lacticco- glycolic acid). X-ray powder diffraction and electron microscopy results revealed differences in crystal arrangement and morphology of the as-synthesized particles. Fourier transform infrared spectroscopy confirmed the presence of corresponding polymers moiety on UCNPs surface providing their biocompatibility and low cytotoxicity towards human gingival fibroblasts (HFG). As a consequence of efficient up-conversion, prominent green emission (between 512-533nm and between 533-560nm) as well as red emission (630-690nm) were recorded in the particles photoluminescence spectra, and these are applied further in the visualization of the HFG using the laser scanning microscopy with a NIR laser source

Trendovi u siliranju leguminoza

Modern trends in legumes ensilaging technology are based on the knowledge of biomass from the aspect of suitability for ensilaging, wilting, addition of carbohydrate feed, use of biological additives, etc. Today, the experiments are conducted, worldwide, with inoculates, which, in addition to homofermentative, also contain heterofermentative lactic acid bacteria. Products of such inoculants contribute to the increase of aerobic stability of silages so their implementation is good for all types of silage. In addition to the usage of those additions, modern technology of silage is based on the maximum mechanization of the ensilaging process, as well as preparing the silage in the form of roto-bales and silo tubes (most inexpensive way of conservation) as well as permanent facilities.Savremeni trendovi u tehnologiji siliranja leguminoza zasnivaju se na poznavanju biomasa sa aspekta pogodnosti za siliranje, provenjavanju, dodavanju ugljenohidratnih hraniva, upotrebi bioloških dodataka, i dr. Trenutno se u svetu eksperimentiše sa inokulantima, koji pored homofermentativnih, sadrže i heterofermentativne bakterije mlečne kiseline. Produkti ovakvih inokulanata doprinose povećanju aerobne stabilnosti silaža, pa su navedeni dodaci aktuelni za sve vrste silaža. Osim korišćenja navedenih dodataka, savremena tehnologija siliranja se bazira na maksimalnoj mehanizovanosti celokupnog procesa siliranja, kao i pripremanja silaže u formi roto-bala i silokobasica (najeftiniji vid konzervisanja) kao i stalnih objekata

Ethylenediaminetetraacetic acid (EDTA) assisted hydro/solvothermal synthesis of up-converting rare earth fluorides

Over the last decade, a lot of effort was directed toward developing of the representative methodologies for the preparation of up-converting (UC) particles which exhibit a unique narrow visible emission when excited by lower-energy photon radiation. This work presents the impact of different processing parameters on structural, morphological and optical properties of up-converting (UC) rare earth fluorides obtained by hydro/solvothermal synthesis. Monodisperse NaYF4:Yb3+/Er3+ particles with different morphology, size and crystal phase were synthesized with a help of ethylenediaminetetraacetic acid (EDTA) through adjusting the precursor concentration, degree of doping, polarity of solvent and reaction time. They are characterized by X-ray powder diffraction, scanning and transmission electron microscopy, energy dispersive X-ray and Furrier transform infrared spectroscopy, as well as photoluminescence measurements. It was shown that particle size and phase composition are dependent on the precursor concentration, type of solvent and doping degree, while the cubic to hexagonal transformation of NaYF4:Yb3+/Er3+ phase is affected by the reaction time. The crystallization of the orthorhombic YF3:Yb3+/Er3+ phase is established either after decreasing concentration of dopants or increasing polarity of solvents. All of the synthesized particles exhibited efficient up-conversion emission which can be tuned from pure green to the yellowish-orange through control of particles size and phase composition

Freshwater algae Cladophora glomerata and Vaucheria sp. from Serbia as sources of bioactive compounds: chemical analysis and biological activities

We examined potential biological activities of two taxa of freshwater algae, Cladophora glomerata and Vaucheria sp., from Serbia. The total phenolic and pigment contents, antioxidant potential, antimicrobial, antibiofilm activities, and cytotoxicity of the ethanol and acetone extracts were evaluated. The extracts were also subjected to Fourier transform infrared spectroscopy (FTIR) analysis. The levels of total phenolic compounds, chlorophylls a and b, and carotenoids varied based on both the algal taxa and the type of extracts. FTIR analysis showed the presence of lipids, unsaturated fatty acids, protein, carbohydrates, and phenols in the algal extracts. The extracts had moderate DPPH radical scavenging activity and lower reducing power compared with ascorbic acid. The antimicrobial activity expressed as minimum inhibitory concentrations ranged from 0.31 mg/mL to 10 mg/mL. The strains of Staphylococcus aureus and Bacillus cereus isolated from food samples, as well as S. aureus ATCC 25923, were the most sensitive. For the first time, the antibiofilm activity test revealed 98.7% inhibition of S. aureus biofilm formation. The extracts exhibited cytotoxic effects on choriocarcinoma JAR cells but without selectivity on normal fetal lung fibroblast MRC-5 cells. This is the first report on the biological activities of freshwater macroalgae from Serbia

Polyacrilic Acid and Chitosan Assisted Solvothermal Synthesis of Up-converting NaYF4: Yb,Er Particles

There is a growing interest for development of a facile and reproducible approach for the synthesis of biocompatible lanthanide doped up-converting nanoparticles (UCNPs) for deep tissue imaging and targeted drug delivery. Synthesis of such particles is usually performed through the decomposition of organometallic compounds, followed either with a ligands exchange or with a biocompatible layer coating. In this work, biocompatible NaYF4:Yb,Er (17 mol% Yb; 3 mol% Er) nanoparticles were synthesized by one-pot hydrothermal processing with an assistance of chitosan (Ch) or polyacrylic acid (PAA). Obtained powders were analyzed by X-ray powder diffraction (XRPD, Bruker D8 Discovery), field emission scanning electron microscopy (FE-SEM, Zeiss, DSM 960), transmission electron microscopy (TEM, JEOL JEM 2010), Fourier transform infrared (FTIR, Thermo Scientific Nicolet 6700) and photoluminescence (PL, Spex Fluorolog with C31034 cooled photomultiplier) spectroscopy. The results showed that although both powders crystallize in the same crystal arrangement (cubic, Fm-3m), particles size, shape and optical properties are dependent on the polymer used

Facile synthesis of hydrophilic polymer-capped upconverting NaYF4:Yb,Er particles

Over the last decade, solvothermal decomposition of organometallic compounds has been indicated as one of the most convenient method for the synthesis of monodisperse lanthanide doped upconverting fluorides. Due to their hydrophobic nature such particles could not be used for a conjugation of the molecular targeting agents which is necessary for optical imaging of biological tissues. In this work, hydrophilic NaYF4:Yb,Er (17 mol% Yb; 3mol% Er) nanoparticles were synthesized by facile one-pot hydrothermal synthesis performed with a help of chitosan (CS) and poly(acrylic acid) (PAA). Obtained powders were analyzed by X-ray powder diffraction (XRPD), field emission scanning electron microscopy (FESEM), Fourier transform infrared (FTIR) and photoluminescence (PL) spectroscopy. The obtained results implied that particle size, shape and surface characteristics are dependent on the polymer choice. Although both powders crystallize in the same crystal arrangement (cubic, Fm-3m) more intense red emission, assigned to the Er3+ 4F9/2 → 4I15/2 electronic transitions, characterize spherical NaYF4:Yb,Er@CS particles. To asses a biological safety of their use, viability of the human gingival fibroblasts (HFG) was additionally tested by a colorimetric MTT assay

Polyacrilic Acid and Chitosan Assisted Solvothermal Synthesis of Up-converting NaYF4: Yb,Er Particles

There is a growing interest for development of a facile and reproducible approach for the synthesis of biocompatible lanthanide doped up-converting nanoparticles (UCNPs) for deep tissue imaging and targeted drug delivery. Synthesis of such particles is usually performed through the decomposition of organometallic compounds, followed either with a ligands exchange or with a biocompatible layer coating. In this work, biocompatible NaYF4:Yb,Er (17 mol% Yb; 3 mol% Er) nanoparticles were synthesized by one-pot hydrothermal processing with an assistance of chitosan (Ch) or polyacrylic acid (PAA). Obtained powders were analyzed by X-ray powder diffraction (XRPD, Bruker D8 Discovery), field emission scanning electron microscopy (FE-SEM, Zeiss, DSM 960), transmission electron microscopy (TEM, JEOL JEM 2010), Fourier transform infrared (FTIR, Thermo Scientific Nicolet 6700) and photoluminescence (PL, Spex Fluorolog with C31034 cooled photomultiplier) spectroscopy. The results showed that although both powders crystallize in the same crystal arrangement (cubic, Fm-3m), particles size, shape and optical properties are dependent on the polymer used

Facile synthesis of hydrophilic polymer-capped upconverting NaYF4:Yb,Er particles

Over the last decade, solvothermal decomposition of organometallic compounds has been indicated as one of the most convenient method for the synthesis of monodisperse lanthanide doped upconverting fluorides. Due to their hydrophobic nature such particles could not be used for a conjugation of the molecular targeting agents which is necessary for optical imaging of biological tissues. In this work, hydrophilic NaYF4:Yb,Er (17 mol% Yb; 3mol% Er) nanoparticles were synthesized by facile one-pot hydrothermal synthesis performed with a help of chitosan (CS) and poly(acrylic acid) (PAA). Obtained powders were analyzed by X-ray powder diffraction (XRPD), field emission scanning electron microscopy (FESEM), Fourier transform infrared (FTIR) and photoluminescence (PL) spectroscopy. The obtained results implied that particle size, shape and surface characteristics are dependent on the polymer choice. Although both powders crystallize in the same crystal arrangement (cubic, Fm-3m) more intense red emission, assigned to the Er3+ 4F9/2 → 4I15/2 electronic transitions, characterize spherical NaYF4:Yb,Er@CS particles. To asses a biological safety of their use, viability of the human gingival fibroblasts (HFG) was additionally tested by a colorimetric MTT assay

Freshwater algae Cladophora glomerata and Vaucheria sp. from Serbia as sources of bioactive compounds: chemical analysis and biological activities

We examined potential biological activities of two taxa of freshwater algae, Cladophora glomerata and Vaucheria sp., from Serbia. The total phenolic and pigment contents, antioxidant potential, antimicrobial, antibiofilm activities, and cytotoxicity of the ethanol and acetone extracts were evaluated. The extracts were also subjected to Fourier transform infrared spectroscopy (FTIR) analysis. The levels of total phenolic compounds, chlorophylls a and b, and carotenoids varied based on both the algal taxa and the type of extracts. FTIR analysis showed the presence of lipids, unsaturated fatty acids, protein, carbohydrates, and phenols in the algal extracts. The extracts had moderate DPPH radical scavenging activity and lower reducing power compared with ascorbic acid. The antimicrobial activity expressed as minimum inhibitory concentrations ranged from 0.31 mg/mL to 10 mg/mL. The strains of Staphylococcus aureus and Bacillus cereus isolated from food samples, as well as S. aureus ATCC 25923, were the most sensitive. For the first time, the antibiofilm activity test revealed 98.7% inhibition of S. aureus biofilm formation. The extracts exhibited cytotoxic effects on choriocarcinoma JAR cells but without selectivity on normal fetal lung fibroblast MRC-5 cells. This is the first report on the biological activities of freshwater macroalgae from Serbia