Essential Oils as Feed AdditivesFuture Perspectives

The inconsistency of phytogenic feed additives' (PFA) effects on the livestock industry poses a risk for their use as a replacement for antibiotic growth promoters. The livestock market is being encouraged to use natural growth promotors, but information is limited about the PFA mode of action. The aim of this paper is to present the complexity of compounds present in essential oils (EOs) and factors that influence biological effects of PFA. In this paper, we highlight various controls and optimization parameters that influence the processes for the standardization of these products. The chemical composition of EOs depends on plant genetics, growth conditions, development stage at harvest, and processes of extracting active compounds. Their biological effects are further influenced by the interaction of phytochemicals and their bioavailability in the gastrointestinal tract of animals. PFA effects on animal health and production are also complex due to various EO antibiotic, antioxidant, anti-quorum sensing, anti-inflammatory, and digestive fluids stimulating activities. Research must focus on reliable methods to identify and control the quality and effects of EOs. In this study, we focused on available microencapsulation techniques of EOs to increase the bioavailability of active compounds, as well as their application in the animal feed additive industry

Natural Macromolecules as Carriers for Essential Oils: From Extraction to Biomedical Application

Essential oils (EOs) and their main constituents, the terpenes, are widely studied, mostly relating to their antioxidant ability and bioactivity, such as antimicrobial, anticancer, anti-inflammatory, and range of other actions in the living systems. However, there is limited information on their bioavailability, especially upon clinical studies. Having in mind both strong biological effects and health benefits of EOs and their specific physicochemical properties (volatility, lipophilic character, low water solubility or insolubility, viscosity, expressed odor, concentration-dependent toxicity, etc.), there is a need for their encapsulation for target delivery. Encapsulation of EOs and their constituents is the prerequisite for enhancing their oxidative stability, thermostability, photostability, shelf life, and biological activity. We considered various carrier types such a (1) monophase and polyphase polysaccharide hydrogel carriers, (2) polysaccharide-protein carriers, and (3) lipid carriers in the context of physicochemical and engineering factors. Physicochemical factors are encapsulation efficiency, chemical stability under gastric conditions, mechanical stability, and thermal stability of carrier matrices. Choice of carrier material also determines the encapsulation technique. Consequently, the engineering factors are related to the advantage and disadvantage of various encapsulation techniques frequently used in the literature. In addition, it was intended to address the interactions between (1) main carrier components, such as polysaccharides, proteins, and lipids themselves (in order to form chemically and mechanically stable structure); (2) main carrier components with pepsin under gastric conditions (in order to form resistant material under gastric conditions); and (3) main carrier components with EOs (in order to enhance encapsulation efficiency), as a necessary precondition for whole process optimization. Finally, different sources for obtaining natural carrier macromolecules are surveyed, especially the agro-waste materials and agricultural and food by-products. This review article highlights the bioavailability aspects of encapsulated EOs and physicochemical and engineering factors concerning natural macromolecule carriers for their target delivery and application

Mathematical modeling of pesticide adsorption on activated hemp fibers

Activated carbon obtained by carbonization and activation of waste hemp fibers was used as an efficient, low-cost sorbent for pesticide removal. Data obtained from batch and continuous process of pesticide adsorption was used for development of the mathematical model that describes the phenomenon of pesticide transport through the porous sorbent matrices. Effective diffusion coefficient and the pesticide concentration profile within the activated hemp fibers, obtained as results of proposed model, give the insight in the mechanism and the rate of adsorption process and pesticide transport through the sorbent. A good agreement between model prediction and the experimental data indicates that the proposed mathematical model can be successfully used for optimization and selection of appropriate adsorption process for pesticide removal

Alginate Gel-Based Carriers for Encapsulation of Carotenoids: On Challenges and Applications

Sodium alginate is one of the most interesting and the most investigated and applied biopolymers due to its advantageous properties. Among them, easy, simple, mild, rapid, non-toxic gelation by divalent cations is the most important. In addition, it is abundant, low-cost, eco-friendly, bio-compatible, bio-adhesive, biodegradable, stable, etc. All those properties were systematically considered within this review. Carotenoids are functional components in the human diet with plenty of health benefits. However, their sensitivity to environmental and process stresses, chemical instability, easy oxidation, low water solubility, and bioavailability limit their food and pharmaceutical applications. Encapsulation may help in overcoming these limitations and within this review, the role of alginate-based encapsulation systems in improving the stability and bioavailability of carotenoids is explored. It may be concluded that all alginate-based systems increase carotenoid stability, but only those of micro- and nano-size, as well as emulsion-based, may improve their low bioaccessibility. In addition, the incorporation of other biopolymers may further improve encapsulation system properties. Furthermore, the main techniques for evaluating the encapsulation are briefly considered. This review critically and profoundly explains the role of alginates in improving the encapsulation process of carotenoids, suggesting the best alternatives for those systems. Moreover, it provides a comprehensive cover of recent advances in this field

Characterization of sodium alginate/D-limonene emulsions and respective calcium alginate/D-limonene beads produced by electrostatic extrusion

In this study, calcium alginate beads immobilizing D-limonene (solid systems) have been manufactured starting from emulsions of this flavor in sodium alginate (liquid systems). The effects of alginate concentration (0.02 and 0.03 g/mL) and flavor content (5 and 10 % w/w) on viscosity, conductivity and stability of emulsions were investigated. The flavor droplets in emulsions are bigger as polymer solution is more concentrated and contains more of the flavor. When emulsions have been subjected to electrostatic extrusion and upon Na+-Ca2+ ion exchange, smaller (similar to 960 to similar to 1450 mm) and less spherical beads were obtained (sphericity factor 0.003-0.21) compared to beads produced by simple dripping technique (without electrostatic field). When wet beads were air dried, they shrunk less if they had higher content of the flavor. Novel mathematical model describing swelling kinetics of dried beads is developed. In this work, D-limonene was efficiently immobilized within Ca-alginate beads (immobilization efficiency similar to 50 to similar to 77%) and its thermal stability was confirmed by TG/MS analysis

The Impact of Ca2+ on Intracellular Distribution of Hemoglobin in Human Erythrocytes

The membrane-bound hemoglobin (Hb) fraction impacts red blood cell (RBC) rheology and metabolism. Therefore, Hb–RBC membrane interactions are precisely controlled. For instance, the signaling function of membrane-bound deoxy-Hb and the structure of the docking sites in the cytosolic domain of the anion exchanger 1 (AE-1) protein are well documented; however, much less is known about the interaction of Hb variants with the erythrocyte’s membrane. Here, we identified factors other than O2 availability that control Hb abundance in the membrane-bound fraction and the possible variant-specific binding selectivity of Hb to the membrane. We show that depletion of extracellular Ca2+ by chelators, or its omission from the extracellular medium, leads to membrane-bound Hb release into the cytosol. The removal of extracellular Ca2+ further triggers the redistribution of HbA0 and HbA2 variants between the membrane and the cytosol in favor of membrane-bound HbA2. Both effects are reversible and are no longer observed upon reintroduction of Ca2+ into the extracellular medium. Fluctuations of cytosolic Ca2+ also impact the pre-membrane Hb pool, resulting in the massive transfer of Hb to the cellular cytosol. We hypothesize that AE-1 is the specific membrane target and discuss the physiological outcomes and possible clinical implications of the Ca2+ regulation of the intracellular Hb distribution

Biomaterijali

Početak XXI veka nesumnjivo je obeležen interdisciplinarnim i multidisciplinarnim naporima istraživača u različitim oblastima nauke. Jedna od najizrazitijih tendencija ovog tipa uočava se u biomedicinskim istraživanjima, gde se združuju napori lekara, biologa, genetičara i biohemičara, s jedne strane, i biofizičara i inženjera, s druge strane – sa ciljem dubljeg razumevanja zdravlja i bolesti, i primene ovih saznanja u biomedicinskoj praksi, tako važnoj u svakodnevnom životu ljudi.Kao rezultat ovih svetskih trendova, u Srbiji već više godina na nekoliko fakulteta postoji nastava iz oblasti biomedicinskog inženjerstva, sa ciljem da osposobi inženjere ovih usmerenja za multidisciplinarno povezivanje znanja iz oblasti tehnike sa biomedicinskim znanjima. Jedan od bazičnih predmeta ovih usmerenja jesu Biomaterijali, kojima je i posvećen naš udžbenik, čiji je cilj da predstavi pregled teorije i prakse biomaterijala u biomedicinskoj nauci.Nauka o biomaterijalima je nesumnjivo najmultidisciplinarnija od svih nauka, jer zahteva ovladavanje znanjima iz mnogih oblasti nauke i tehnologije, inženjerstva i medicine, kako bi naučnici iz oblasti biomaterijala mogli da se uhvate u koštac sa ovom profesijom. Zato posle uvodnog dela, udžbenik iz Biomaterijala sadrži četiri celine: (I) Osnovni biomedicinski koncepti i reakcije organizma na biomaterijale, (II) Struktura, fizičko-mehanička karakterizacija i modeliranje biomaterijala i tkiva, (III) Savremeni biomaterijali i tehnologije, (IV) Perspektive biomaterijala i tehnologija, iza kojih slede Zadaci sa rešenjima, Ispitna test pitanja i Ispitna teorijska pitanja, koji pomažu studentima da lakše savladaju veoma obimno i kompleksno gradivo. Na kraju svakog poglavlja data su pitanja za rekapitulaciju, kao i spisak dopunske literature za opcionu detaljniju obradu pojedinih oblasti.Grupa od dvadeset četiri profesionalca sa univerziteta i naučnih instituta, pod okriljem Instituta tehničkih nauka Srpske akademije nauka i umetnosti, Beograd, i Društva za istraživanje materijala Srbije (MRS Srbija) doprinela je pisanju ovog kapitalnog udžbenika o biomaterijalima, prvog do sada na srpskom jeziku. Mada uključivanje veće grupe autora nužno dovodi do stilske neujednačenosti, ipak je oblast biomaterijala toliko multidisciplinarna da je ovakav pristup bio neophodan, kako uostalom pokazuju slična svetska iskustva sa uključivanjem i preko pedeset autora. Ipak urednici su se potrudili da koliko je to moguće stilski i pedagoški ujednače udžbenik, kako bi bio korisna literatura za sve studente diplomskih, master i doktorskih studija iz biomedicinskog inženjerstva u Srbiji i okruženju

Biomaterijali

Početak XXI veka nesumnjivo je obeležen interdisciplinarnim i multidisciplinarnim naporima istraživača u različitim oblastima nauke. Jedna od najizrazitijih tendencija ovog tipa uočava se u biomedicinskim istraživanjima, gde se združuju napori lekara, biologa, genetičara i biohemičara, s jedne strane, i biofizičara i inženjera, s druge strane – sa ciljem dubljeg razumevanja zdravlja i bolesti, i primene ovih saznanja u biomedicinskoj praksi, tako važnoj u svakodnevnom životu ljudi.Kao rezultat ovih svetskih trendova, u Srbiji već više godina na nekoliko fakulteta postoji nastava iz oblasti biomedicinskog inženjerstva, sa ciljem da osposobi inženjere ovih usmerenja za multidisciplinarno povezivanje znanja iz oblasti tehnike sa biomedicinskim znanjima. Jedan od bazičnih predmeta ovih usmerenja jesu Biomaterijali, kojima je i posvećen naš udžbenik, čiji je cilj da predstavi pregled teorije i prakse biomaterijala u biomedicinskoj nauci.Nauka o biomaterijalima je nesumnjivo najmultidisciplinarnija od svih nauka, jer zahteva ovladavanje znanjima iz mnogih oblasti nauke i tehnologije, inženjerstva i medicine, kako bi naučnici iz oblasti biomaterijala mogli da se uhvate u koštac sa ovom profesijom. Zato posle uvodnog dela, udžbenik iz Biomaterijala sadrži četiri celine: (I) Osnovni biomedicinski koncepti i reakcije organizma na biomaterijale, (II) Struktura, fizičko-mehanička karakterizacija i modeliranje biomaterijala i tkiva, (III) Savremeni biomaterijali i tehnologije, (IV) Perspektive biomaterijala i tehnologija, iza kojih slede Zadaci sa rešenjima, Ispitna test pitanja i Ispitna teorijska pitanja, koji pomažu studentima da lakše savladaju veoma obimno i kompleksno gradivo. Na kraju svakog poglavlja data su pitanja za rekapitulaciju, kao i spisak dopunske literature za opcionu detaljniju obradu pojedinih oblasti.Grupa od dvadeset četiri profesionalca sa univerziteta i naučnih instituta, pod okriljem Instituta tehničkih nauka Srpske akademije nauka i umetnosti, Beograd, i Društva za istraživanje materijala Srbije (MRS Srbija) doprinela je pisanju ovog kapitalnog udžbenika o biomaterijalima, prvog do sada na srpskom jeziku. Mada uključivanje veće grupe autora nužno dovodi do stilske neujednačenosti, ipak je oblast biomaterijala toliko multidisciplinarna da je ovakav pristup bio neophodan, kako uostalom pokazuju slična svetska iskustva sa uključivanjem i preko pedeset autora. Ipak urednici su se potrudili da koliko je to moguće stilski i pedagoški ujednače udžbenik, kako bi bio korisna literatura za sve studente diplomskih, master i doktorskih studija iz biomedicinskog inženjerstva u Srbiji i okruženju

Erythrocytes under osmotic stress - modeling considerations

Various modeling approaches have been applied to describe structural changes of the erythrocyte constituents under osmotic stress. The constituents: (1) the lipid bilayer, (2) the actin spectrin cortex, (3) the trans-membrane protein band 3, (4) the intracellular hemoglobin contribute to the relaxation phenomenon. Cells response includes the successive sub-bioprocesses: (1) erythrocyte swelling, (2) lifetime of the lipid structural integrity and the rearrangements of trans-membrane protein band 3, (3) the reversible hemolytic hole formation and hemoglobin release to surrounding solution. Herein, an attempt is made to discuss and connect various modeling approaches on various time scales which have been proposed in the literature in order to shed further light to this complex phenomenon which induces the erythrocyte to ghost phase transition. The results indicate that the erythrocyte swelling rate represents the key control factor for the structural ordering of the cell parts which induces anomalous nature of energy dissipation

Micro-environmentally restricted hybridoma cell growth within polysaccharide hydrogel microbeads

The mechanism of micro-environmentally restricted hybridoma cell growth caused by action of local mechanical compression stress generated within various polysaccharide hydrogel matrixes is estimated by comparing the growth of hybridoma cells within (1) 1.5% Ca-alginate microbeads from Bugarski et al. [in: Fundamentals of Animal Cells Immobilization and Microencapsulation, M. F. A. Goosen, ed., CRC Press, Boca Raton, FL, 1993, p. 267] and (2) 1.3% alginate-agarose microbeads from Shen et al. [Animal Cell Technology: Basic & Applied Aspects, H. Murakami ed., Kluwer Academic Publishers, The Netherlands, 1992, p. 173]. Consideration of restricted cell growth dynamics based on developed kinetic model and kinetic 3D Monte Carlo simulation include: (1) changes the fraction of active proliferating cells in the exponential phase and (2) changes of non-proliferating cell concentration in the plateau phase. Higher value of the specific decrease of active fraction of proliferating cells. is obtained for 1.3% alginate-agarose compared to 1.5% alginate microbeads. It corresponds to higher compression stress generated within hydrogel matrix during cell growth obtained for 1.3% alginate-agarose microbeads