Objectives
The chemical composition, antimicrobial and synergistic effect, and cytotoxic activity of Citrus limon (lemon), Piper nigrum (green pepper) and Melaleuca alternifoila (tea tree) essential ...oils (EOs) were investigated.
Methods
Chemical analyses of essential oils were tested by GC‐FID and GC‐MS spectroscopy. The antimicrobial activity assay was conducted using microdilution method against several oral bacteria and Candida spp. originating from the humans with oral disorders. The synergistic antimicrobial activity was evaluated using checkerboard method. The cytotoxicity evaluation of EOs was assessed using MTT test.
Key findings
Limonene (37.5%) and β‐pinene (17.9%) were the major compounds in C. limon oil, β‐pinene (34.4%), δ‐3‐carene (19.7%), limonene (18.7%) and α‐pinene (10.4%) in P. nigrum oil and terpinen‐4‐ol (38.6%) and γ‐terpinene (21.7%) in M. alternifolia oil. The broad‐spectrum antimicrobial activity was achieved by tested three EOs, with C. limon oil being the strongest against bacteria and M. alternifolia oil strongest against fungi. The EOs demonstrated synergism; their combined application revealed an increase in antimicrobial activity. All tested essential oils showed lower cytotoxic activity in comparison with the positive control, and the obtained results confirmed a dose‐dependent activity.
Conclusions
The results of this study encourage use of tested EOs in development of a novel agent intended for prevention or therapy of corresponding oral disorders.
This article is focused on attitudes of the local population within the border municipalities in the Euroregion “Drina-Sava-Majevica,” on the further development of sport-event tourism. The survey ...research obtained a sample of 238 respondents. Collected data were analyzed by using the SPSS (21.0). Analysis of categorical variables (Chi-square test) and coefficients of correlation, together with descriptive statistics, indicated that the local community has reliable attitudes on potentials for development of sport-events, as well as the most popular “Drinska regatta.” However, members of the local community still do not recognize possibilities of using tourism resources for gaining personal and community-wide benefits. Therefore, efforts aimed at further tourism development within the researched border municipalities should be valorized and adequately represented in the tourism market in cooperation with the local population.
Background/Aim. The longevity of a dental restoration may be predicted to some degree by its adhesive ability, and this, in turn, can be measured by bond strength testing between restorative ...materials and tooth structure. The aim of this study was to test an innovative joggle lap shearing jig that integrates the tooth and the entire biomechanical unit into testing, to compare the shear bond strengths of Class I occlusal composite restorations in deep cavity preparations lined with Dycal, Dycal LC, conventional glass ionomer or resin-modified glass ionomer. The mode of failure (adhesive, cohesive, mixed) after debonding was determined by stereomicroscopy. Methods. A total of 150 standardized occlusal cavities were prepared and divided into five groups. The group I cavities (n = 30) were coated with adhesive (ExciTE?F) and filled directly with composite (TetricEvoCeram). The group II and III cavities were lined with Dycal (n = 30) or Dycal LC (n = 30) before placing composite. The groups IV and V specimens were based with Fuji IX (n = 30) or Fuji II LC (n = 30). Shear bond strengths were determined with a universal testing machine and fractured bonding sites were analyzed under stereomicroscope. The mean bond strengths were analyzed using one-way ANOVA test (p < 0.05) and the means between the groups were analyzed with Student?s t-test. Results. The shear bond strength (MPa) of composite restorations in cavities without base (23.91 ? 4.54) was higher than cavities lined with Fuji II LC (17.45 ? 2.74), Fuji IX (8.76 ? 2.57), Dycal LC (13.07 ? 1.84) or Dycal (6.12 ? 1.28). The results using the jogged lap shearing jig were consistent with the literature. Conclusion. The shear bond strength of occlusal composite restorations in deep cavities without liners was greater than cavities lined with Fuji II LC > Fuji IX > Dycal LC > Dycal.
nema
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, ODKLJ, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
The relationship between fluoride content and fluoride release for glass-ionomer cements is not well understood. The aim of this laboratory study was: to determine the fluoride concentrations at the ...surfaces of glass-ionomer materials with respect to different storage media and different pH environments; to examine the recharge ability of the materials after NaF immersion; and to assess the morphological changes at the material surfaces using scanning electron microscope and energy dispersive spectroscopic techniques (SEM/EDS).
Five glass-ionomer materials, Fuji Triage (FT), Fuji II LC (FII), Fuji VIII (FVIII), Fuji IX GP (FIX), and Ketac N100 (KN), were analyzed in this study. Resin-based fluoride releasing material Helioseal F (HSF) was used as a comparison material. The sample consisted of 120 cured cement disks (n = 20 disks of each tested material, 10 x 1.5 mm). Five disks of each material were stored in 4 different storage media (I- saline, II- acidic solution ph = 2.5, III- acid solution ph = 5.5, IV- NaF solution (c = 500/106). After 7 days, two disks of each material were transferred from media I, II and III to the NaF solution for 3 min. EDS analysis was conducted in 3 randomly selected spots of each experimental disk. SEM was used to determine morphological characteristics of the material surface. Differences between the experimental groups have been analyzed using Student's t-test with the level of significance set at p < 0.001.
FT showed the highest fluoride content at the surface of the material. The lowest amounts of fluoride ions were detected at the surfaces of the FT disks stored at low pH environments, and this difference was statistically significant (p < 0.001). Glass-ionomers showed significantly higher fluoride concentrations when compared to the HSF (p < 0.001). After immersion in the NaF solution, fluoride concentrations at the surfaces of the disks increased when compared with previous storage media (FT>FVIII>KN>FII>FIX). SEM analysis of the surface morphology revealed numerous voids, cracks and microporosities in all experimental groups, except for KN and HSF. More homogenous material structure with more discrete cracks was observed in samples stored at neutral pH environment, compared to disks stored in acidic solutions.
The tested materials could be considered as promising dental materials with potential prophylactic characteristics due to their relatively high fluoride content, but also the ability to extensively reabsorb fluoride ions, especially in acidic environments.
One of the most efficient prophylactic measures in caries prevention is sealing pits and fissures. After improvements of physical and mechanical properties, glass-ionomers are frequently used as ...sealing materials. The aim of this study was to evaluate the prophylactic efficiency of Fuji VII, a glass-ionomer fissure sealant, through adaptation ability and fluoride reeasing potential assessment using scanning electron microscopic and energy dispersive spectroscopic techniques. The sample consisted of 20 extracted intact human teeth, 10 premolars and 10 molars. Six sections of each tooth were analyzed using SEM. EDS analysis was conducted one week and three months after material placement. The parameters used for the evaluation included: adaptation ability, penetration depth, material structure, integrity of the interfacial zone and ion exchange extent. The sealant penetration depth was observed at 30 X magnification, and the interfacial zone between the material and the enamel at 500-10000 X. EDS was used for quantitative analysis of the material structure, interfacial zone and the enamel surface. The results were statistically analyzed the using chisquare test and descriptive statistical methods. SEM analysis revealed the zone of interaction between the enamel surface and the glass-ionomer with predominant cohesive failures within the sealant material, and satisfactory adaptation ability of the sealing material. The mean value of the penetration was 83% of the total fissure depth, without a statistically significant difference between the tested teeth groups. A lower penetration ability was observed in deep pits and fissures with a larger diameter of unfilled space (p<0.05). EDS analysis revealed the potential of the glass-ionomer for ion exchange with dental tissues. The presence of fluoride ions was detected in 2 sections 3 months after material placement. Glass-ionomers, chemically cured, biocompatible materials demonstrate satisfactory prophylactic characteristics.
Cilj ove studije je bio da se proceni profilakticka efikasnost glasjonomera, Fuji VII, analizom kvaliteta adaptacije i potencijala oslobadjanja fluorida. Uzorak je cinilo 20 intaktnih ekstrahovanih zuba, i 6 preseka svakog zuba analizirano je SEM-om. EDS analiza je uradjena 7 i 90 dana nakon aplikacije materijala. Procenjivani parametri su ukljucivali: kvalitet povrsinske adaptacije, dubinu penetracije, strukturu materijala, medjuspoja i povrsine gledji, i analizu jonske razmene materijala i zuba. SEM analizom je potvrdjena zona adaptacije materijala uz povrsinu gledji, sa kohezionim frakturama glasjonomera. Penetracija materijala iznosila je u proseku 83% dubine fisure. EDS analizom je pokazan potencijal za otpustanje fluorida. Glasjonomeri, hemijski-vezujuci biokompatibilni materijali pokazuju zadovoljavajuce profilakticke karakteristike.
Restoring carious teeth is one of the major dental treatment needs of young children. Conventional glassionomer materials are frequently used as filling materials in contemporary pediatric dentistry. ...The objective of this study was to evaluate the restorative and prophylactic efficacy of the newly marketed glass ionomer, Fuji Triage (GC, Tokyo, Japan), through morphological analysis of the interface zone between the material and the enamel and the dentin of primary molars and to determine the extent of the ion exchange at the interface zone. The sample consisted of 5 extracted intact first primary molars in which glassionomer had been used as filling material after standard class I cavity preparation. The material was placed according to the manufacturer's instructions and teeth were placed into dionised water prior to experiment. Six sections of each tooth had been examined using scanning electron microscopic and electron dispersive spectroscopic techniques (SEM/EDS). The parameters for evaluation included: morphological characteristics of the interface zone and the extent of the ion exchange between the material and the tooth structures Results were statistically analyzed using descriptive statistical methods. SEM/EDS analysis revealed the presence of the chemical bonding between the glass ionomer and the enamel and dentin, 5 and 15 ?m in width, respectively. Ion exchange has not been detected in the enamel at the EDS sensitivity level. Strontium and fluor penetration has been detected in dentin. The ion exchange and chemical bonding formation justify the usage of the conventional glass ionomer materials for restorative procedures in primary molars.
Cilj studije bio je da se praceni restorativna i profilakticka efikasnost glasjonomera, Fuji Triage, morfoloskom, analizom medjuspoja i jonske razmene izmedju materijala i gledi i dentina. Na 5 ekstrahovanih prvih mlecnih molara postavljen je glasjonomerni materijal i 6 preseka analizirano je pomocu skening elektronskog mikroskopa opremljenog energetskim disperzionim spektrometrom, SEM/EDS. Procenjivani parametri: morfoloske karakteristike i kvantitet razmene jona izmedju materijala i gledji i dentina. SEM/EDS analizom je pokazana zona kemijske veze glasjonomera i gledji i dentina, dimenzija 5 i 15 ?m, respektivno. Jonska razmena na ovom nivou osetljivosti nije detektovana u gledi. Penetracija jona fluora i stroncijuma pokazana je u dentinu. Razmena jona i formiranje kemijske veze opravdavaju upotrebu glasjonomernih materijala u decjoj stomatologiji.
In this paper, we present a possible application of memristive switches for implementation of main-line mounted loaded-line phase shifters. The underlining idea is to replace PIN diodes, acting as ...RF/microwave switches, with memristors in order to reduce power consumption. As a proof-of-concept, circuit-level simulations are performed to validate the expected functionality. Parasitic effects caused by the memristor programming circuitry, which might be relevant at RF/microwave frequencies, are taken into consideration. Pi's model is used to represent memristors at RF/microwave frequencies and Biolek's model is used for exploring the memristance setting issues. Our simulation results make memristors the promising candidates for the phase shifters.
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•Memristor-based main-line mounted loaded-line phase shifters•Reduce power consumption by replacing PIN diode RF/microwave switches with memristors•Use Pi's memristor model for RF/microwave simulations•Use Biolek's model for memristance setting analysis•Validate the proposed concept by microwave-circuit-level simulations
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•New coumarine derivatives and palladium(II) complexes were synthesized.•Characterized by microanalysis, infrared, 1H and 13C NMR spectroscopy.•Monocrystal X-ray structural analysis ...and DFT calculations.•Antimicrobial activity for ligands and complexes is investigated.
The five coumarin derivatives 3-(1-(2-hydroxypropylamino)ethylidene)-chroman-2,4-dione (L1), 3-(1-(phenylamino)ethylidene)-chroman-2,4-dione (L2), 3-(1-(o-toluidino)ethylidene)-chroman-2,4-dione (L3), 3-(1-(m-toluidino)ethylidene)-chroman-2,4-dione (L4), 3-(1-(2-mercaptoethylamino)ethylidene)-chroman-2,4-dione (L5) and its corresponding complexes 3-(1-(2-hydroxypropylamino)-ethylidene)-chroman-2,4-dione-palladium(II) (C1), 3-(1-(phenylamino)-ethylidene)-chroman-2,4-dione-palladium(II) (C2), 3-(1-(o-toluidino)-ethylidene)-chroman-2,4-dione-palladium(II) (C3), 3-(1-(m-toluidino)ethylidene)-chroman-2,4-dione-palladium(II) (C4), 3-(1-(2-mercaptoethylamino)ethylidene)-chroman-2,4-dione-palladium(II) (C5), were synthesized and characterized with microanalysis, infrared, 1H and 13C NMR spectroscopy. The proposed structures of ligands L3 and L4 were confirmed on the basis of the X-ray structural study. The ligands and their complexes were tested for their in vitro antimicrobial activity against 17 species of bacteria and fungi. Testing is performed by the microdilution method, with the minimum inhibitory concentration (MIC) and the minimum microbicidal concentration (MMC) being determined.
In the present study, five root extracts of Onosma visianii Clem were investigated for their in vitro cytotoxic activity. On the basis of HPLC-PDA analysis, these extracts have proved to be a rich ...source of naphthoquinones as natural colourants for food and cosmetic industry. All investigated root extracts contain acetylshikonin, isobutyrylshikonin and α-methylbutyrylshikonin as major compounds. As the most abundant source of active compounds for antitumour therapy, acetone, chloroform and ethyl acetate extracts showed strong cytotoxic activity towards HCT-116 and MDA-MB-231 cancer cell lines. Also, these extracts induced apoptosis and cell cycle arrest in HCT-116 and MDA-MB-231 cancer cell lines.
Paper presents short review of research problems, applied methods for solving
problems and main results obtained by the researchers in Laboratory for
Thermal Engineering and Energy (LTE) of the ..."Vinca" Institute of Nuclear
Sciences, Belgrade, Serbia dealing with pulverized coal combustion processes
and technologies for reduction of pollutions problems at thermal power
plants in a period since 2000. The presented results were published in
numerous studies realized for different users, Ph. D., Masters, and
Specialist thesis, in international and domestic scientific journals and
monographs, presented at numerous international and domestic scientific
conferences, etc. Presented research projects and results of applied
research projects realized at pulverized coal combustion thermal power
plants clearly show that LTE team was involved in key activities of
rehabilitation and modernization, including implementation of best
available technologies for pollution reduction at thermal power plants, in
the region of South East Europe.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
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