Advantage of use of activated flux-cored wire instead of solid wire with the mag welding process from the mechanical properties aspect

The objective of this paper is the analysis and evaluation of the quality of the new flux-cored wire designed for the MAG welding process that was developed and produced using special laboratory equipment. Experimental welding was performed with the new activated flux-cored wire and classic solid wire with changing of welding parameters and shielding gas composition (100 % CO2 and gas mixtures of Ar + CO2 + O2)

Development of bio-based chitosan films with incorporated chestnut extract

Hydrolysable tannins have prominent biological activity and thus their industrial application is gaining importance in many fields. This study explored the possibility for the utilization of a commercially available chestnut extract (CE) as an active component in chitosan-based films intended for food packaging. Therefore, a set of chitosan-based films with incorporated CE was prepared and evaluated regarding physicochemical properties. The estimated total phenolic content (TPC) has revealed a maximal value of 19.5 mgGAE gfilm-1. Moreover, the moisture content (MC) in the films has decreased (from 29.6% to 18.6%), while tensile strength (TS) has increased (from 13.5 MPa to 48.5 MPa) after the incorporation of CE. The observed coherence between TPC and evaluated properties has been confirmed by the existence of strong negative and positive linear correlations in the case of MC and TS, respectively. In large, CE extract was found to be a promising candidate as an active component in chitosan-based films

1H- and 13C-NMR Study of Naphtho[2,1-b]thiophene and Naphtho[2,1-b]furan Derivatives

A series of four substituted naphtho[2,l-b]thiophenes 1-4 and a series of five substituted naphtho[2,l-b] furans 5-9 have been studied using one- and two-dimensional 1H- and 13C-NMR methods. Chemical shifts of protons could not be assigned on the basis of the homonuclear correlation (COSY) spectra only, but two-dimensional nuclear Overhauser (NOESY) spectroscopy had to be used. The cross-peak between HI and H9 enabled unequivocal assignation of the H6-H9 four proton spin system. On the bases of NOE measurements of the naphtho[2,l-b]thiophene 3, it was possible to estimate the interatom distances between HI and H9 protons of 209 pm, and between HI and H2 of 244 pm, respectively. Chemical shifts of substituted carbons were assigned using two-dimensional 1H/13C heteronuclear correlation (HET- COR) spectra. The substitution effect and the effect of solvent on the chemical shifts of the furan and thiophene analogues are reported, and the coupling constants VH H were determined

Advanced surgical techniques in gingival recession treatment

Uvod Mukogingivalne anomalije se ispoljavaju kao posledica anatomo-morfoloških nepravilnosti u mukogingivalnom kompleksu parodontalnih tkiva i predstavljaju odstupanje od normalne dimenzije i morfologije u meĊusobnom odnosu gingive i alveolarne mukoze, a takoĊe mogu biti povezane i sa deformitetima alveolarne kosti. S obzirom na veliku uĉestalost u humanoj populaciji, one predstavljaju znaĉajan socio-epidemiološki problem. Gingivalna recesija predstavlja najĉešću mukogingivalnu anomaliju i nastaje usled morfoloških nepravilnosti u mukogingivalnom kompleksu. Gingivalna recesija ima uticaj na nastanak i prognozu parodontopatije i ukoliko se ne leĉi moţe da dovede do gubitka zuba. Odlikuje se gubitkom mekih i ĉvrstih tkiva u mukogingivalnom regionu, što dovodi do povećane osetljivosti eksponiranog korena zuba na nadraţaje i nepovoljnog estetskog izgleda. Terapija gingivalne recesije je hirurška. Realan cilj terapije gingivalne recesije jeste kompletno, predvidivo i u znaĉajnom periodu vremena stabilno prekrivanje površine korena zuba. U hirurškom leĉenju gingivalne recesije gornjih zuba najĉešće korištena terapijska metoda je Transplantat vezivnog tkiva u kombinaciji sa koronarno pomerenim reţnjem i vertikalnim relaksacijama, dok se u terapiji gingivalne recesije donjih zuba najĉešće primenjuje Slobodni mukozni autotransplantat. Materijal i metod U studiju je ukljuĉeno 20 pacijenata Klinike za Parodontologiju i oralnu medicinu Stomatološkog fakulteta u Beogradu. Kriterijumi za ukljuĉivanje u studiju bili su bilateralno prisusutvo izolovanih ili multiplih gingivalnih recesija klase I ili II po Miller-u u gornjoj vilici. Primenjen je metod podeljenih usta (“splith mouth”).svi pacijenti su podeljeni u dve grupe, prvu grupu su saĉinjavali pacijenti sa gingivalnim recesijama na gornjim zubima dok su drugu grupu ĉinili pacijenti sa gingivalnim recesijama na donjim zubima...Background Mucogingival deformities result from anatomical and morphological irregularities in the mucogingival region. Gingival recession is the most common mucogingival deformity, and it represents a displacement of gingival margin apically from cement enamel junction. It presents itself with both a loss of soft and of hard tissues. The treatement of gingival recession is surgical. A ideal goal of gingival recession treatment is complete restauration of lost periodontal tissues. Subepithelial connective tissue graft in combination with coronally advanced flap is most common therapeutic approach in treatment of maxillary recession. On the other hand, Free gingival graft is first choise in treatment of mandibular recessions. Material and methods 20 patients from Department of Periodontology, School of Dentistry, University of Belgrade, have been enrolled in the study. Inclusion criterion was the bilateral presence of Miller class I or II single or multiple maxillary or mandibular gingival recessions. Split mouth design was used in the study. Patients were divided in two groups, in first group were patients with recessions localized on maxillary teeth and in second group were patients with recessions localized on mandibular teeth. In experimental group- first group of patients, gingival recessions were treated with Subepithelial connective tissue graft in combinatiom with split thickness flap (Tunel technique). In control group, gingival recessions were treated with Subepithelial connective tissue graft placed under a coronally advanced flap (Allen 1994). In experimental group, second group of patients, gingival recessions were treated with Subepithelial connective tissue graft in combination with split thickness flap (Tunel technique). In control group, gingival recessions were treated with Free gingival graft. Clinical parameters such as gingival recession coverage (RC), keratinized tissue width (KG), clinical attachment level (CAL), gingival index (GI) and plaque index (PI) were recorded at baseline, and three and six months postoperatively..

Analysis of causes of degradation of parent material and weld metal of breeches pipe at hydro power plant 'Perućica'

Presented are results of non-destructive tests performed on the parent material and welded joints of structural parts of a breeches pipe (collar and anchor), and results of destructive tests performed on the parent material of the anchor. Non-destructive testing included visual (VT), mag-netic particle (MT), and ultrasonic testing (UT), while destructive tests included determination of chemical com-position, tensile properties, impact energy and hardness. Based on test results it is established that the major cause for the occurrence of damage in the carrying structure of the breeches pipe no.1 of pipeline III, or in other words, the degradation of anchor parent material and welded joints between the collar and anchor, and between the pipeline and anchor, is in the fact that the breeches pipe started to lean, not on the collar, as specified by design, but on the anchor that could not endure all loads occurring in service

Analysis of causes of degradation of parent material and weld metal of breeches pipe at hydro power plant 'Perućica'

Presented are results of non-destructive tests performed on the parent material and welded joints of structural parts of a breeches pipe (collar and anchor), and results of destructive tests performed on the parent material of the anchor. Non-destructive testing included visual (VT), mag-netic particle (MT), and ultrasonic testing (UT), while destructive tests included determination of chemical com-position, tensile properties, impact energy and hardness. Based on test results it is established that the major cause for the occurrence of damage in the carrying structure of the breeches pipe no.1 of pipeline III, or in other words, the degradation of anchor parent material and welded joints between the collar and anchor, and between the pipeline and anchor, is in the fact that the breeches pipe started to lean, not on the collar, as specified by design, but on the anchor that could not endure all loads occurring in service

Biodegradability study of active chitosan biopolymer films enriched with Quercus polyphenol extract in different soil types

One of the recent trends within the circular economy is the development of materials derived from food processing waste and their utility as an alternative to plastic packaging. In this context, the study aims to evaluate biological causes of deterioration or degradation of chitosan-based films with and without incorporated natural Quercus polyphenol extract in three different types of soils (industrial compost, commercial garden soil, and soil from a vineyard). Degradation and active properties deterioration was followed by measurement of the loss of mass of tested active films for 14 days, and it was accompanied by other analytical techniques such as measurement of polyphenolic content, FT-IR analysis, and SEM examination of the packaging morphology. The results showed that chitosan-based film properties deteriorate in less than 3 days followed by biodegradation in all tested soils after 14 days. Films with incorporated Quercus polyphenol extract undergo deterioration of active properties in compost and garden soil in 6 days, while the fractionation and degradation process has not been complete in the vineyard soil during the 14 days. Furthermore, it has also been revealed that the addition of water to the soil decreased the rate of active chitosan film biodegradation in the terrestrial environment

Synthesis of Diarylamidines

Diarilamidini su klasa organskih spojeva različite kemijske strukture, čiji se mehanizam djelovanja temelji na nekovalentnim interakcijama u malom utoru DNA. Radi priprave biološki aktivnih spojeva iz klase diarilamidina do danas su provedene brojne sinteze, koje su dovele do razvoja novih sintetskih postupaka kao i priprave novih reagensa i katalizatora. U ovom radu navedene su najčešće primjenjivane sintetske metode priprave diarilamidina.Diarylamidines is a class of compounds of different chemical structure, whose mechanism of action is based on their noncovalent interactions with the minor groove of DNA. The numerous chemical syntheses carried out during the preparation of diarylamidines have led to the development of new synthetic methods and the preparation of new reagents and catalysts. This article summarizes the most used synthetic methods for preparation of diarylamidines

Reduction in Spoilage Microbiota and Cyclopiazonic Acid Mycotoxin with Chestnut Extract Enriched Chitosan Packaging: Stability of Inoculated Gouda Cheese

Active chitosan-based films, blended with fibrous chestnut (Castanea sativa Mill.) tannin-rich extract were used to pack Gouda cheese that has been contaminated with spoilage microflora Pseudomonas fluorescens, Escherichia coli, and fungi Penicillium commune. A comprehensive experimental plan including active chitosan-based films with (i) chestnut extract (CE), (ii) tannic acid (TA), and (iii) without additives was applied to evaluate the film′s effect on induced microbiological spoilage reduction and chemical indices of commercial Gouda cheese during 37 days while stored at 4 °C and 25 °C, respectively. The cheese underwent microbiology analysis and chemical assessments of ultra-high-performance liquid chromatography (UHPLC) (cyclopiazonic acid), pH, and moisture content. The biopackaging used for packing cheese was characterized by mechanical properties before food packaging and analyzed with the same chemical analysis. The cheese microbiology showed that the bacterial counts were most efficiently decreased by the film without additives. However, active films with CE and TA were more effective as they did not break down around the cheese and showed protective properties against mycotoxin, moisture loss, and pH changes. Films themselves, when next to high-fat content food, changed their pH to less acidic, acted as absorbers, and degraded without plant-derived additives