Bubrenje i termodinamička analiza temperaturno osetljivih 2- hidroksietil metakrilat/itakonska kiselina kopolimernih hidrogelova sintetisanih gama zračenjem

Sintetisani su kopolimerni hidrogelovi na bazi 2-hidroksietil metakrilata (HEMA) i itakonske kiseline (IA) polimerizacijom indukovanom gama zračenjem. Analizirani su proces bubrenja i termodinamičke osobine PHEMA i kopolimernih P(HEMA/IA) hidrogelova sa različitim sadržajem IA (2, 3.5 i 5 mol %) u širokom opsegu pH i temperature. Preliminarne analize gelova pokazuju interesantnu pH i temperatursku osetljivost u procesima bubrenja i otpuštanja lekova. Posebna pažnja posvećena je temperaturama u okolini fiziološke (37o C), gde male promene u temperaturi značajno utiču na stepen bubrenja i proces otpuštanaj lekova. Ispitivan je P(HEMA/IA) hidrogel sa 5mol% IA sa i bez antibiotika (gentamicin) na pH 7.40 i u temperaturskom intervalu 25- 42o C, u cilju praćenja mogućnosti njihovog korišćenja u medicini

Gelatin-/Alginate-Based Hydrogel Scaffolds Reinforced with TiO2 Nanoparticles for Simultaneous Release of Allantoin, Caffeic Acid, and Quercetin as Multi-Target Wound Therapy Platform

This study proposes synthesis and evaluation of gelatin-/alginate-based hydrogel scaffolds reinforced with titanium dioxide (TiO2) nanoparticles which, through their combination with allantoin, quercetin, and caffeic acid, provide multi-target therapy directed on all phases of the wound healing process. These scaffolds provide the simultaneous release of bioactive agents and concurrently support cell/tissue repair through the replicated structure of a native extracellular matrix. The hydrogel scaffolds were synthesized via a crosslinking reaction using EDC as a crosslinker for gelatin. Synthesized hydrogel scaffolds and the effect of TiO2 on their properties were characterized by structural, mechanical, morphological, and swelling properties, and the porosity, wettability, adhesion to skin tissue, and simultaneous release features. The biocompatibility of the scaffolds was tested in vitro on fibroblasts (MRC5 cells) and in vivo (Caenorhabditis elegans) in a survival probe. The scaffolds revealed porous interconnected morphology, porosity of 88.33 to 96.76%, elastic modulus of 1.53 to 4.29 MPa, full hydrophilicity, favorable skin adhesivity, and biocompatibility. The simultaneous release was investigated in vitro indicating dependence on the scaffold’s composition and type of bioactive agents. The novel scaffolds designed as multi-target therapy have significant promise for improved wound healing in a beneficial and non-invasive manner

Uticaj agrotehničkih mera u proizvodnji soje na otpor prodiranja konusa u zemljište

The results of this research considered the influence of sub soiling and manure on penetrometer cone indexes were presented in this paper. Standard technology, employing plows for the basic soil tillage, was used in the production of soya bean. Four variants in to 3 repetition were implied during researching. In the first variant the soil was only plowed. In the second variant the soil subsoiled after winter barley harvesting and then plowed. In the third variant manure was spread out and then plowed and in the fourth variant the soil was subsoiled, manure was spread out and at the and soil was plowed. The same soil was subject of the two-year research, more exactly the same farming measures were applied two year continually. The cone index was measured by electronic penetrometer two times during vegetation, the first time after sowing, and the second after soya bean harvesting. The average cone index at the depth of 3.5 to 24.5 cm was used to determine the influence of subsoiler and manure. The lowest values of cone index were measured in variants where manure was spread out, which clearly indicates that the spreading the manure is an appropriate farming measure for the reduction of soil compaction. The influence of subsoiler has not lead to the significant changes in cone index relative to the first control variant for two years. Besides, after F-test ANOVA it was shown that there were not statistically significant differences at the significance threshold of 5% in neither of either variants. The largest yields were measured in variants in which livestock manure was spread out, more exactly in variants 3 and 4. In yield comparison to the control variant it was shown that in variant 2 where subsoiler was applied the yield was increased by 6.84%, in variant 3 where livestock manure was applied the yield was increased by 33.05%, and in the variant 4 where subsoiler and livestock manure were applied the yield was increased by 35.33%.U radu su prikazani rezultati ispitivanja uticaja podrivanja i svinjskog stajnjaka na otpor prodiranja konusa penetrometra. Za proizvodnju soje primenjena je klasična tehnologija kod koje se osnovna obrada obavlja plugovima. Tokom ispitivanja obuhvaćene su četiri varijante u 3 ponavljanja. U prvoj varijanti zemljište je samo orano plugom. U drugoj varijanti zemljište je podriveno nakon ubiranja ozimog ječma, a zatim poorano. U trećoj varijanti po zemljištu rasturen je svinjski stajnjak, pa zatim zaoran i u četvrtoj varijanti zemljište je podriveno, rasturen je stajnjak, koji je potom isto zaoran. Isto zemljište je predmet dvogodišnjeg ispitivanja, odnosno iste mere primenjene su dve godine kontinualno. Otpor prodiranja konusa meren je elektronskim penetrometrom dva puta u toku vegetacije, prvi put nakon setve, a drugi put nakon ubiranja soje. Za analizu uticaja podrivanja i stajnjaka korišćen je otpor konusa na dubini od 3,5 do 24,5 cm. Najmanje vrednosti otpora konusa izmerene su u varijantama gde se primenio stajnjak, što jasno ukazuje da je unošenje stajnjaka prava agrotehnička mera za smanjenje sabijenosti zemljišta. Uticaj podrivanja i nakon dve godine primene nije doveo do značajnih promena u otporu konusa u odnosu na kontrolnu varijantu. Ipak, nakon statističke analiza pokazalo se da ni na jednoj varijanti nisu dobijene statistički značajne razlike u otporu konusa za prag značajnosti 0,05%. Najveći prinosi izmereni su isto kod varijanti gde se primenio stajnjak, odnosno na varijanti 3 i 4. Poređenjem prinosa soje vidi se da je kod varijante 2 sa podrivačem prinos povećan za 6,84%, kod varijante 3 gde je primenjen samo stajnjak povećan za 33,05%, a kod varijante 4 gde je primenjeno podrivanje i stajnjak za 35,33%

Uticaj agrotehničkih mera na zapreminsku masu zemljišta

The aim of this research was to consider the influence of certain farming measures on soil compaction that is on the soil volume. The implementation of this farming measure would enable an increase in production and reduction of soil compaction. The soil volume expressed in Mg m-3 was determined by Kopecky cylinder. The soil volume was used for determining soil compaction due to its indirect relation to soil porosity. The soil samples were taken in the period of fertilization at the distance of 1m from the left side of the permanent tracks, and after the period of harvest they were taken at the distance of 1 m from the right side of the wheel tracks, and from the central part of the headland. The same method was used for the inner part of the parcel. The soil volume was determined at the depth of 0-30 cm. The measurement was conducted in spring, prior to fertilization and at the end of vegetation, that is, after the harvest of winter barley. Standard technology, employing plows for the basic soil tillage, was used in the production of winter barley and was applied in the first, control field. The pre-cultivar was sunflower. Certain farming measures were applied upon sunflower harvesting and before soil plowing. Every experimental field was 18 m wide and 100 m long. There were seven experimental fields, in three replicates, on the headland and inner part of the parcel: - the first field was the control one without any applied measures, - in the second fled, subsoiler was used for the basic soil tillage instead of a plow, - in the third field, the plow was used but 50 t/ha of manure was spread out, - in the fourth field, the plow was used and 200 kg/ha of mineral fertilizer was spread out, - in the fifth field, subsoiler was used and 50 t/ha of manure was spread out, - in the sixth field, subsoiler was used and 200 kg/ha of mineral fertilizer was spread out, - in the seventh field, the plow was used and the soil was fertilized with microbiological fertilizer. Tractor system was designed in such a way so that tractor wheels could overlap on the parcel. Accordingly, 18 m wide field was chosen since the working area of wheat seed drill was 6 m, and working area for mineral fertilizer spreading machine and field sprayer was 18 m. The soil compaction on the headlands prior to fertilization was 9.66% higher in comparison to the inner part, while after the harvest, this difference was 17.30%. The lowest soil volume was measured on the third and fifth field, before fertilization and after the harvest. These fields were fertilized by manure, which clearly indicates that the spreading the manure is an appropriate farming measure for the reduction of soil compaction. If applied for a year, the influence of other farming measures cannot lead to significant changes in soil volume.U radu su prikazani rezultati ispitivanja uticaja agrotehničkih mera na sabijenost zemljišta, odnosno zapreminsku masu zemljišta na uvratini i unutrašnjem delu parcele. Za proizvodnju ozimog ječma primenjena je klasična tehnologija kod koje se osnovna obrada obavlja plugovima i ona je primenjena na prvom, odnosno kontrolnom polju. Nakon ubiranja suncokreta, a pre oranja zemljišta primenjene su odgovarajuće agrotehničke mere. Agrotehničke mere obuhvatile su primenu razrivača, svinjskog stajnjaka, mineralnog đubriva i mikrobiloškog đubriva na 7 različitih polja u tri ponavljanja. Zapreminska masa merena je pre prihrane i nakon ubiranja ozimog ječma. Sabijenost zemljišta na uvratinama pre prihrane bila je za 9,66% veća u odnosu na unutrašnji deo, dok je nakon ubiranja razlika bila veća i iznosi 17,30%. Najmanje vrednosti zapreminske mase zemljišta izmerene su pre prihrane i posle ubiranja na poljima 3 i 5, gde je unet stajnjak, što jasno ukazuje da je unošenje stajnjaka prava agrotehnička mera za smanjenje sabijenosti zemljišta. Uticaj ostalih agrotehničkih mera ne može da dovede do značajnih promena u zapreminskoj masi zemljišta ako se primene jednu godinu

Analiza uticaja traktora i mobilnih sistema na promene u zemljištu i prinos suncokreta

This paper shows the results of analysis of soil compaction influence on sunflower yield on headland and inner part of a field, and chemical changes in soil. Soil compaction after sprouting was 67.70 % greater on headland than in the inner part, while before harvesting, there was an increase of 13.44 % in soil compaction. Large number of passages, which caused intensified soil compaction on headlands, poor conditions for the root system development, and poor microbiological activities led to yield reduction, which was 8.98% in total mass and 9.13% in dry grain mass. Chemical analysis of soil on headland and in the inner part of a field showed almost the same humus, nitrogen and other macroelements concentration on headlands and in the inner part of a field.U radu su prikazani rezultati ispitivanja uticaja sabijanja zemljišta na uvratinama i unutrašnjem delu parcele na prinos suncokreta i hemijske promene u zemljištu. Sabijenost zemljišta na uvratinama posle setve bila je za 67,70 % veća u odnosu na unutrašnji deo, dok je povećanje sabijenosti zemljišta na uvratini pre ubiranja iznosilo 13,44 %. Veliki broj prelaza doveo je do intenzivnijeg sabijanja zemljišta na uvratinama, uslovljavajući nepovoljne uslove za razvoj korenovog sistema i slabije mikrobiološke aktivnosti, radi čega smanjenje biološkog prinosa iznosi 8,98 %, a mase suvog zrna 9,13 %. Hemijska analiza sastava zemljišta na uvratini i unutrašnjem delu parcele pokazala je da je sadržaj humusa na uvratinama i u unutrašnjem delu pacele skoro isti, kao i sadržaj azota i ostalih makrohraniva

Uticaj agrotehničkih mera na otpor konusa kod ozimog ječma

This paper shows the results of analysis of scientific farming measures influence on soil compaction, more exactly on cone resistance on headland and inner part of a field. Soil compaction before fertilizing was 57,27% greater on headland than in the inner part, while after harvesting, there was an increase of 50,97% in soil compaction. The results of research show that it is impossible to increase quality of land on one time period. More years are needed and using manure.U radu su prikazani rezultati ispitivanja uticaja agrotehničkih mera na sabijenost zemljišta, odnosno otpor prodiranja konusa penetrometra na uvratini i unutrašnjem delu parcele. Sabijenost zemljišta na uvratinama pre prihrane bila je za 57,27% veća u odnosu na unutrašnji deo, dok je nakon ubiranja razlika bila manja i iznosi 50,97%. Rezultati istraživanja pokazali su da se ne može značajno uticati na smanjenje sabijanja zemljišta za jednu godinu. Za to je potrebno više godina i primena stajnjaka

Istraživanje uticaja sabijenosti zemljišta na prinos suncokreta i promene u zemljištu na uvratinama i unutrašnjem delu parcele

This paper shows the results of analysis of soil compaction influence on sunflower yield on headland and inner part of a field, chemical and biological changes in soil. During the 5 years investigation, soil compaction after sowing was 23.01% greater on headland than in the inner part, while before harvesting, there was an increase of 28.43% in soil compaction. Large number of passages, which caused intensified soil compaction on headlands, poor conditions for the root system development, and poor microbiological activities led to yield reduction, which was 33.57% in total mass and 35.25% in dry grain mass. Chemical analysis of soil on headland and in the inner part of a field showed higher humus concentration on headlands, due to poor microbiological activities.U radu su prikazani rezultati ispitivanja uticaja sabijanja zemljišta na uvratinama i unutrašnjem delu parcele na prinos suncokreta, hemijske i biološke promene u zemljištu. Sabijenost zemljišta na uvratinama tokom 5 godina ispitivanja posle setve bila je za 23,01% veća u odnosu na unutrašnji deo, dok je povećanje sabijenosti zemljišta na uvratini pre ubiranja iznosilo 28,43%. Velik broj prelaza doveo je do intenzivnijeg sabijanja zemljišta na uvratinama, uslovljavajući nepovoljne uslove za razvoj korenovog sistema i slabije mikrobiološke aktivnosti, radi čega smanjenje biološkog prinosa iznosi 33,57%, a mase suvog zrna 35,25%. Hemijska analiza sastava zemljišta na uvratini i unutrašnjem delu parcele pokazala je da je veći sadržaj humusa na uvratinama nego u unutrašnjem delu pacele zbog slabije mikrobiološke aktivnosti

Uticaj sabijenosti zemljišta na promene u zemljištu i prinos suncokreta

This paper shows the results of analysis of soil compaction influence on sunflower yield on headland and inner part of a field, and chemical changes in soil. Soil compaction after sprouting was 67.70% greater on headland than in the inner part, while before harvesting, there was an increase of 13.44% in soil compaction. Large number of passages, which caused intensified soil compaction on headlands, poor conditions for the root system development, and poor microbiological activities led to yield reduction, which was 8.98% in total mass and 9.13% in dry grain mass. Chemical analysis of soil on headland and in the inner part of a field showed almost the same humus, nitrogen and other microelements concentration on headlands and in the inner part of a field. The total number of microorganisms is larger in the inner part of the field, while the number of actinomycetes is larger on headland. There are no significant differences in numbers of nitric bacteria and fungus.U radu su prikazani rezultati ispitivanja uticaja sabijanja zemljišta na uvratinama i unutrašnjem delu parcele na prinos suncokreta, hemijske i biološke promene u zemljištu. Sabijenost zemljišta na uvratinama posle setve bila je za 67,70% veća u odnosu na unutrašnji deo, dok je povećanje sabijenosti zemljišta na uvratini pre ubiranja iznosilo 13,44%. Veliki broj prelaza doveo je do intenzivnijeg sabijanja zemljišta na uvratinama, uslovljavajući nepovoljne uslove za razvoj korenovog sistema i slabije mikrobiološke aktivnosti, radi čega smanjenje biološkog prinosa iznosi 8,98%, a mase suvog zrna 9,13%. Hemijska analiza sastava zemljišta na uvratini i unutrašnjem delu parcele pokazala je da je sadržaj humusa na uvratinama i u unutrašnjem delu pacele skoro isti, kao i sadržaj azota i ostalih makrohraniva. Ukupan broj mikrooganizama je veći u centralnom delu parcele, dok je broj aktinomiceta veći na uvratinama. Značajnije razlike u broju azotobaktera i broj gljivica ne postoje

Istraživanje uticaja sabijenosti zemljišta na prinos pšenice i promene u zemljištu na uvratinama i unutrašnjem delu parcele

This paper shows the results of analysis of soil compaction influence on wheat yield, chemical and biological changes in a soil on headland and inner part of a field. During five years of investigation, soil compaction after sowing was 30.56% greater on headland than in the inner part, while before harvest, an increase in soil compaction was 37.65%. Large number of passages, which caused intensified soil compaction on headlands, poor conditions for the root system development, and poor microbiological activities led to yield reduction, which was 31.55% in biological yield and 26.39% in dry grain mass. Chemical analysis of soil on headland and in the inner part of a field showed higher humus concentration on headlands, due to poor microbiological activities.U radu su prikazani rezultati ispitivanja uticaja sabijanja zemljišta na uvratinama i unutrašnjem delu parcele na prinos pšenice, hemijske i biološke promene u zemljištu. Sabijenost zemljišta na uvratinama tokom 5 godina ispitivanja posle setve bila je za 30.56% veća u odnosu na unutrašnji deo, dok je povećanje sabijenosti zemljišta na uvratini pre ubiranja iznosilo 37.65%. Velik broj prelaza doveo je do intenzivnijeg sabijanja zemljišta na uvratinama, uslovljavajući nepovoljne uslove za razvoj korenovog sistema i slabije mikrobiološke aktivnosti radi čega smanjenje biološkog prinosa iznosi 31.55%, a mase suvog zrna 26.39%. Hemijska analiza sastava zemljišta na uvratini i unutrašnjem delu parcele pokazala je da je veći sadržaj humusa na uvratinama nego u unutrašnjem delu parcele zbog slabije mikrobiološke aktivnosti

Antimicrobial Activity of Silver, Copper, and Zinc Ions/Poly(Acrylate/Itaconic Acid) Hydrogel Matrices

The design and use of new potent and specific antimicrobial systems are of crucial importance in the medical field. This will help relieve, fight, and eradicate infections and thus improve human health. The use of metals in various forms as antimicrobial therapeutics has been known since ancient times. In this sense, polymeric hydrogel matrices as multifunctional materials and in combination with various metal forms can be a great alternative to conventional treatments for infections. Hydrogels possess high hydrophilicity, specific three-dimensional networks, fine biocompatibility, and cell adhesion and are therefore suitable as materials for the loading of active antimicrobial agents and acting in antimicrobial areas. The biocompatible nature of hydrogels’ matrices makes them a convenient starting platform to develop biocompatible, selective, active controlled-release antimicrobial materials. Hydrogels based on acrylate and itaconic acid were synthesized and loaded with silver (Ag+), copper (Cu2+), and zinc (Zn2+) ions as a controlled release and antimicrobial system to test release properties and antimicrobial activity in contact with microbes. The metal ions/hydrogel systems exhibited favorable biocompatibility, release profiles, and antimicrobial activity against methicillin-sensitive Staphylococcus aureus (MSSA), methicillin-resistant Staphylococcus aureus (MRSA), Staphylococcus aureus, Escherichia coli, and Candida albicans microbes, and have shown that they have the capacity to “fight” with the life-threatening infections. Antimicrobial activity depends on types of metal ions, the composition of polymeric matrices, as well as the types of microbes. Designed metal ions/poly(acrylate/itaconic acid) antimicrobial systems have shown to have good potential as antimicrobial therapeutics and suitable biomaterials for medical applications