12 research outputs found
Chemical risk factors responsible for the formation of wedge-shaped lesions
Introduction: Non-carious tooth substances loss pose a major health problem of a modern man. The literature often collectively describes all non-carious lesions and is therefore difficult to compare results obtained by different authors. Chemical factors are one of the predisposing factors responsible for the formation of wedge-shaped erosions. Aim: Examination of chemical risk factors as one of the predisposing causes responsible for the formation of wedge-shaped lesions. Method: We examined 62 patients with wedge-shaped erosions (mean age 45.52 ± 12.03 years, 58.1% of men) and 60 patients without erosions in the control group (mean age 34.40 ± 9.28 years, 60% men) . The entire examination was completed by using a questionnaire at the Dental Clinic of the University of Pristina - Kosovska Mitrovica. salivary pH was measured by the pH meter. Results: The results show that the wedge-shaped lesions often occur equally in both men and women. Considerably often it might appear in older people but can also occur in teenagers. Patients with wedge-shaped erosion have increased acidity of saliva, a heightened sense of acid in the mouth and consume a lot more carbonated drinks compared to patients without erosions. Conclusion: Wedge-shaped lesions are more common in people older than 40 years. Taking into account the results obtained in this study it can be concluded that the chemical risk factors truly fall within the predisposing factors that may be responsible for the creation of wedge-shaped erosions
Coumarin derivatives act as novel inhibitors of human dipeptidyl peptidase III: combined in vitro and in silico study
Dipeptidyl peptidase III (DPP III), a zinc- dependent exopeptidase, is a member of the metalloproteinase family M49 with distribution detected in almost all forms of life. Although the physiological role of human DPP III (hDPP III) is not yet fully elucidated, its involvement in pathophysiological processes such as mammalian pain modulation, blood pressure regulation, and cancer processes, underscores the need to find new hDPP III inhibitors. In this research, five series of structurally different coumarin derivatives were studied to provide a relationship between their inhibitory profile toward hDPP III combining an in vitro assay with an in silico molecular modeling study. The experimental results showed that 26 of the 40 tested compounds exhibited hDPP III inhibitory activity at a concentration of 10 µM. Compound 12 (3-benzoyl-7-hydroxy-2H-chromen-2-one) proved to be the most potent inhibitor with IC50 value of 1.10 μM. QSAR modeling indicates that the presence of larger substituents with double and triple bonds and aromatic hydroxyl groups on coumarin derivatives increases their inhibitory activity. Docking predicts that 12 binds to the region of inter-domain cleft of hDPP III while binding mode analysis obtained by MD simulations revealed the importance of 7- OH group on the coumarin core as well as enzyme residues Ile315, Ser317, Glu329, Phe381, Pro387, and Ile390 for the mechanism of the binding pattern and compound 12 stabilization. The present investigation, for the first time, provides an insight into the inhibitory effect of coumarin derivatives on this human metalloproteinase
Influence of hydrocolloids and sweeteners on flow behaviour of peach nectar
Influence of adding six hydrocolloids, guar gum, carrageenan, carboxymethylcellulose and three types of pectin, and of sweeteners, aspartame and fructose, as replacement of sucrose, on flow behaviour of peach nectar was studied. A series of peach nectar samples (with approximately 65% fruit) was prepared using commercially processed peach purée with sucrose and substituting sugar with low-calorie sweetener aspartame and fructose (alone and in combination in a sweetness ratio of 1:1) taking into account their sweetness. To prevent reduction of viscosity and mouthfeel/body of low-calorie peach nectars, different concentrations of hydrocolloids were added. A control sample was prepared by mixing fruit purée with a sucrose solution (7% mass fraction) to provide a 14% (in total solids) nectar. Rheological measurements were carried out on a rotational viscosimeter Rheotest 3 at 20 C and 5°C. The flow of all peach nectars was characterized as pseudoplastic. Among all used hydrocolloids, addition of only 0.03% of carrageenan to the peach nectar was enough to obtain viscosity similar to the viscosity of the control sample
Investigation of 16% carbamide-peroxide on the structure and properties and effect return enamel staining teeth whitening after their
The most tooth whitening is a procedure that removes stains and various discolorations of tooth surface. Discoloration of teeth may be endogenous and exogenous nature. The aim of this study was to investigate the impact of bleaching combined with daily use of drinks that cause tooth discoloration. Evaluated the changes in surface structure of enamel, and changes in hardness after bleaching. Were 20 extracted teeth. The teeth are marked with longitudinal lines halves (medial vestibular and distal surfaces). Tretitana mesial half of the 16% carbamide peroxide, a distal was left as control. NDT device HL-400DL, duroskopskom method of enamel hardness was measured before treatment, after treatment and after remineralization. Olympus inverted microscope GX41 enamel structures were observed in the treated and control half of the tooth. After bleaching there is a difference compared to the untreated surface, that surface is bleached a few shades lighter, but after the use of coffee and soft drinks teeth back to the original dark color. Enamel microhardness after the treatment is somewhat small but not significant. With a magnification of 2000x and see the structural changes in enamel. Tooth whitening, but that the remineralization and the abstinence from prebojenih beverages and tobacco
Influence of the operating parameters on the flux during microfiltration of the steepwater in the starch industry
The subject of the work is the possibility of applying microfiltration through a ceramic tubular membrane with 100 nm pore sizes to the steepwater obtained in the production process of corn starch. The dry matter content should be reduced in the steepwater permeate. Thus the consumption of the process water would be reduced, the nutrients from the steepwater could be exploited as feed and the wastewater problem would consequently be solved. The objective of the work was to examine the influence of the operating parameters on the permeate flux during steepwater microfiltration. The parameters that vary in the course of microfiltration, were the transmembrane pressur and flow rate, while the permeate flux and dry matter content of the permeate and retentate were the dependent parameters, constantly monitored during the process. Another objective of this study was to investigate the influence of static turbulence promoter on the permeate flux during steepwater microfiltration. Static mixers enhance permeate flux, thus the microfiltration can be performed longer. As a result of the statistical analysis, the optimal conditions for steepwater microfiltration were determined. The maximum value of the permeate flux without mixer (25 lm-2h-1) was achieved at a pressure of 2 bars and a flow rate around 100 lh-1. With the use of static mixer the flux is 2,5 times higher compared to the one obtained without the mixer. The dry matter content of the permeat after 2.5 hours of mucrofiltration was lowered by 40%
Molecular and Supra‐Molecular Structural Ordering of Wheat Starch‐OSA Modified Waxy Maize Starch Mixtures During Storage
The influence of waxy maize OSA starches on the retrogradation kinetics of wheat starch pastes is investigated using dynamic oscillatory rheological and differential scanning calorimetry (DSC) measurements. Total starch concentration for the rheological experiments is 4% (w/w) and wheat starch/OSA starch ratios are 100/0, 90/10, and 80/20. A modified fractional Kelvin-Voigt model is proposed to interpret system behavior under low oscillatory shear conditions and get deeper insight into its structural changes during storage. The results indicate that structural ordering of the systems composed of wheat starch and a) non-physically modified (OSA-ST); b) pregelatinized (Pregel OSA-ST); and c) hydrolyzed/spray dried (Hydrol OSA-ST) starches is governed by different molecular mechanisms. OSA-ST retarded short-term aging (7 days) of wheat starch gel due to amylose dilution with partially disrupted OSA-ST granules as well as the steric effect of OS groups. However, enthalpies of wheat starch/OSA-ST mixtures stored for 14 days were similar to that of wheat starch alone. On the contrary, both the rheological and DSC results suggest that mixtures containing Pregel OSA-ST and Hydrol OSA-ST retrograde slower than wheat starch gel during short and long storage. The model systems investigated in this study may represent a useful tool to understand the functionality of OSA starches as anti-staling additives in breadmaking