Solution proposal for completed preference structure in ORESTE method.

In this study, a novel integrated method including CRITIC (Criteria Importance Through Inter-Criteria Correlation) and ORESTE (Organisation, Rangement Et Synth&e De DonnCes Relarionnelles) methods from MCDM (multi-criteria decision making) methods and aiming to solve the problem of inconsistency in the ORESTE method has been proposed. Since the ORESTE method only considers the ordering of alternatives and criteria, a conflict may occur due to the different ordering of each alternative in the criteria. To solve the conflict problem in the second step of the ORESTE method, it is proposed to create the preference density matrix of the alternatives by using the CRITIC weights of the criteria, and to calculate the net flow values with reference to the PROMETHEE II (Preference Ranking Organization Method for Encrichment Evaluations II) method (C-ORESTE III). The CRITIC method is used because the relationship between the criteria is as important as the alternatives in calculating the normalized preference intensities. To test the validity and applicability of the proposed method, an application is made to the logistics center location problem within the scope of green logistics.

Ionic Liquid-Modified Gold Nanoparticle-Based Colorimetric Sensor for Perchlorate Detection via Anion-π Interaction.

A rapid and convenient nanoparticle(NP)-based colorimetric sensor was developed for determining the propellant oxidant, ammonium perchlorate (AP). The sensing element was manufactured by modifying gold nanoparticles (AuNPs) with [(1-methyl-1H-imidazol-2-yl)sulfanyl]acetic acid, which is an imidazolium-based ionic liquid (IL), to produce the IL@AuNP nanosensor stabilized by polyvinylpyrrolidone. The used IL is an exceptional IL which can attach to AuNPs through the sulfanyl-S atom. The sensing principle was based on observing the red shift in the surface plasmon resonance band of AuNPs leading to NP aggregation as a result of anion-π interaction of perchlorate anion with the zwitterionic form of IL@AuNPs so as to bring opposite charges face-to-face, thereby reducing the overall surface charge of NPs. The surface plasmon resonance band of AuNPs at 540 nm shifted to 700 nm as a result of aggregation. The ratiometric sensing was performed by dividing the absorbance at 700 nm to the absorbance at 540 nm and correlating this ratio to the AP concentration. The limit of detection and limit of quantification of the sensor for AP were 1.50 and 4.95 µM, respectively. Possible interferences of other energetic substances and common soil ions in synthetic mixtures were also investigated to achieve acceptable recoveries of analyte. This work may pioneer similar sensing systems where the overall anionic charges of IL-functionalized AuNPs are exceptionally reduced by an analyte anion (perchlorate), thereby forcing NPs to aggregate.

Detection of nitric oxide radical and determination of its scavenging activity by antioxidants using spectrophotometric and spectrofluorometric methods.

Although reactive nitrogen species (RNS) may attack biomacromolecules and cause tissue damage when unbalanced by natural antioxidant defenses of the organism, they can also take part in cell signaling under different physiological states and defend against certain pathogens. Since there is a scarcity of analytical methods to detect radicalic NO and its scavengers, a functionalized gold nanoparticle-based spectrophotometric method and a spectrofluorometric method have been separately developed to test antioxidant activity toward scavenging of NO produced from sodium nitroprusside (SNP). The spectrophotometric method involves conversion of NO to nitrite, followed by the formation of an azo dye with 4-aminothiophenol (4-ATP)-modified gold nanoparticles (AuNPs) and N-(1-naphthyl)-ethylene diamine dichloride (NED) and its absorbance measurement at 565 nm. Calibration equations were established by taking the absorbance difference in the presence and absence of antioxidants. In the spectrofluorometric method, the excess of NO radicals, after being scavenged by thiol type antioxidants, caused a decrease in resorcinol fluorescence. The developed spectrophotometric method was applied to orange juice and its trolox equivalent (TE) antioxidant activity was found. By further applying the developed methods to real samples such as bovine serum albumin (BSA), fetal bovine serum (FBS), saliva and certain biomolecules, it is envisaged that these novel methods improving the selectivity of previous methods can be useful in human health and disease research associated with nitric oxide. The developed methods were compared and validated against the conventional Griess assay with Student t-test and F tests.

Magnetite nanoparticles-based hydroxyl radical scavenging activity assay of antioxidants using N, N-dimethyl-p-phenylenediamine probe.

Excessive amounts of reactive oxygen species (ROS), unless counterbalanced by antioxidants, can cause cellular damage under oxidative stress conditions; therefore, antioxidative defenses against ROS must be measured. With the development of nanotechnology, nanoparticles have found numerous applications in science, health, and industries. Magnetite nanoparticles (Fe 3 O 4 :MNPs) have attracted attention because of their peroxidase-like activity. In this study, hydroxyl radicals (•OH) generated by MNPs-catalyzed degradation of H 2 O 2 converted the N,N-dimethyl-p-phenylenediamine (DMPD) probe into its colored DMPD•+ radical cation, which gave an absorbance maximum at λ = 553 nm. In the presence of antioxidants, •OH was partly scavenged by antioxidants and produced less DMPD• + , causing a decrease in the 553 nm-absorbance. Antioxidant concentrations were calculated with the aid of absorbance differences between the reference and sample solutions. The linear working ranges and trolox equivalent antioxidant capacity coefficients of different classes of antioxidants were determined by applying the developed method. In addition, binary and ternary mixtures of antioxidants were tested to observe the additivity of absorbances of mixture constituents. The method was applied to real samples such as orange juice and green tea. Student t-test, F tests, and the Spearman's rank correlation coefficient were used for statistical comparisons.

Colorimetric sensing of ammonium perchlorate using methylene Blue-Modified gold nanoparticles.

This work aims to develop a sensitive and easily applicable gold nanoparticles (AuNPs)-based colorimetric sensor for determining the propellant ammonium perchlorate (AP) in the presence of other explosives and interferents. The sensor relied on attaching methylene blue (MB), a phenothiazine dye with a planar structure, onto negatively charged AuNPs, and exploited the dye's electrostatic interactions with the large oxyanion, perchlorate. Ion-pair formation between MB@AuNP nanocomposite and AP led to nanoparticle aggregation, causing a red shift in the surface plasmon resonance (SPR) band of AuNPs. This new peak emerged at around 650 nm, giving rise to the development of a ratiometric sensor by taking the ratio of 650 nm absorbance to that at 520 nm (pertaining to nanocomposite) and correlating this ratio to AP concentration. The limit of detection (LOD) and limit of quantification (LOQ) of the sensor for AP were 2.4 × 10-5 and 8.3 × 10-5 mol L-1, respectively. The recovery of AP from ternary mixtures containing TNT and HMX was accomplished by water extraction using solubility differences. The interferences of common soil ions such as Cl-, NO3-, NO2-, SO42-, CH3COO-, K+, Mg2+ and Ca2+ were investigated, and the assay was statistically compared (using t- and F- tests) against a reference method. The proposed method could accurately determine perchlorate in a sparkler sample.

Effect of chitosan nanoparticle, QMix, and EDTA on TotalFill BC sealers' dentinal tubule penetration: a confocal laser scanning microscopy study.

The aim of the present study was to compare the effect of chitosan nanoparticle, QMix, and 17% EDTA on the penetrability of a calcium silicate-based sealer into dentinal tubules using a confocal laser scanning microscope (CLSM). Sixty mandibular premolar teeth were selected and randomly divided into three groups (n = 20) before root canal preparation according to the solution used in the final rinse protocol: chitosan, QMix, and EDTA groups. Twenty teeth of each group were filled with a TotalFill BC sealers' single gutta-percha cone and with 0.1% rhodamine B. The specimens were horizontally sectioned at 3 and 5 mm from the apex, and the slices were analyzed in CLSM (4×). Total percentage and maximum depth of sealer penetration were measured using confocal laser scanning microscopy with using Image J analysis software. Dentinal tubule's penetration depth, percentage, and area were measured using imaging software. Kruskal-Wallis test was used for statistical analysis. The level of significance was set at 5%. Results of Kruskal-Wallis analysis showed that there was a significant difference in the percentage and depth of sealer penetration among all groups at 3 and 5 mm level sections (P < 0.05). Within the groups, the minimum sealer penetration depth was recorded for chitosan nanoparticle group. Greater depth of sealer penetration was recorded at 5 mm as compared to 3 mm in all the groups. Within the limitation of the present study, it can be concluded that QMix and EDTA promoted sealer penetration superior to that achieved by chitosan nanoparticle.

Three-year clinical evaluation of class II posterior composite restorations placed with different techniques and flowable composite linings in endodontically treated teeth.

OBJECTIVE: The objective of this study is to evaluate the clinical performance of direct resin composite restorations placed with different techniques (incremental or bulk) and different flowable linings (conventional or bulk-fill) in endodontically treated teeth. MATERIALS AND METHODS: Forty-seven pair class II (mesio-occlusal or disto-occlusal) composite restorations were placed in 37 patients. In all cavities, Adper Single Bond 2 was used. In one of the cavities of each pair, a conventional flowable composite, Aelite Flo, was applied in approximately 2 mm thick, and the remaining cavity was restored incrementally with GrandioSO. In the second cavity, a bulk-fill flowable composite, x-tra base, was applied in approximately 4 mm thick in bulk increments and the remaining 2-mm occlusal part of the cavity was restored with GrandioSO. All cavities were restored with open-sandwich technique by the same operator. At baseline and after 6-month, 1-, 2-, and 3-year follow-up visits, restorations were evaluated by modified USPHS criteria. RESULTS: At 3-year recall, 33 restorations with Aelite Flo lining and 33 with x-tra base lining were available. Two restorations from each group (6.0 %) were scored as Bravo in terms of surface texture. One restoration's color match from x-tra base group scored as Bravo (3.0 %). All other evaluated criteria were scored as Alfa (100 %) for all restorations. No statistically significant difference between the two groups was found in all evaluated criteria during 3-year period (p > 0.05). CONCLUSION: Bulk-filling technique showed clinically acceptable performance comparable to the incremental technique. CLINICAL RELEVANCE: Restorations placed with bulk-filling technique with x-tra base lining and incremental technique with a conventional flowable lining showed highly clinical performance over 3-year period.