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The purpose of this cross-sectional study was to evaluate the mental fear and anxiety about coronavirus disease 2019 (COVID-19) among Korean clinical dental hygienists and to investigate factors influencing the anxiety felt after the outbreak of COVID-19.A questionnaire on mental fear (Fear-C) and anxiety for COVID-19 was conducted among 500 clinical dental hygienists in South Korea. Fear-C was identified with eight questions. The General Anxiety Disorder-7 (GAD-7) questionnaire was scored for the pre-COVID-19 situation (GADThe average Fear-C was 16.11 ± 3.89 out of 24.00. There were significant differences in Fear-C when the type of work organization and symptoms related to COVID-19 (Sx-C) differed. Significant differences were confirmed in GADMost dental hygienists complained of Fear-C. GAD

Korean Red Ginseng (KRG) was reported to play an anti-inflammatory role, however, previous studies largely focused on the effects of KRG on priming step, the inflammation-preparing step, and the anti-inflammatory effect of KRG on triggering, the inflammation-activating step has been poorly understood. This study demonstrated anti-inflammatory role of KRG in caspase-11 non-canonical inflammasome activation in macrophages during triggering of inflammatory responses.Caspase-11 non-canonical inflammasome-activated J774A.1 macrophages were established by priming with Pam3CSK4 and triggering with lipopolysaccharide (LPS). Cell viability and pyroptosis were examined by MTT and lactate dehydrogenase (LDH) assays. Nitric oxide (NO)-inhibitory effect of KRG was assessed using a NO production assay. Expression and proteolytic cleavage of proteins were examined by Western blotting analysis.KRG reduced LPS-stimulated NO production in J774A.1 cells and suppressed pyroptosis and IL-1β secretion in caspase-11 non-canonical inflammasome-activated J774A.1 cells. Mechanistic studies demonstrated that KRG suppressed the direct interaction between LPS and caspase-11 and inhibited proteolytic processing of both caspase-11 and gasdermin D in caspase-11 non-canonical inflammasome-activated J774A.1 cells. Furthermore, KRG significantly ameliorated LPS-mediated lethal septic shock in mice.The results demonstrate a novel mechanism of KRG-mediated anti-inflammatory action that operates through targeting the caspase-11 non-canonical inflammasome at triggering step of macrophage-mediated inflammatory response.

To evaluate infection control knowledge and its practice of clinical dental hygienists in response to Coronavirus Disease 2019 (COVID-19) in South Korea.Nine questions (Q9-K) on the degree of knowledge acquisition of dental hygienists in response to COVID-19, and another 9 questions (Q9-P) on the practices for COVID-19 infection and spread prevention were prepared. From 500 clinical dental hygienists in South Korea, answers about their general characteristics, Q9-K, and Q9-P were collected. 1 point was given to each question based on the 'yes' answers from Q9-K and Q9-P, and Score-K and Score-P were calculated, respectively. To identify factors affecting Score-P, a multiple linear regression analysis was performed. In all analyses, p-values lower than 0.05 were considered statistically significant.Average scores of Score-K and Score-P were 7.36 ± 1.35 and 6.26 ± 2.07, respectively. The regression model of Score-P was significant (F = 20.788, p 0.001). Concerning Score-P, Score-K (β = 0.385), age (β = 0.275), dental hospital (β = 0.158), monthly income of $2,360~$2,730 (β = 0.104) had a significantly positive correlation, and the total years of career (β = -0.293) are found to have a significantly negative correlation.Infection control knowledge and practice of clinical dental hygienists in South Korea was found to be vulnerable in the group of hygienists who are younger than 27 years old, working in dental clinics, and whose monthly income is less than under $2,000. Also, the factor that influences infection control practice the most was the degree of knowledge. Therefore, continuous infection control education and supplement targeting these vulnerable groups are necessary.

This study investigates the quality characteristics and antioxidant activities of milk jam with black garlic extract at levels of 0%, 7.5%, 15.0%, 22.5% and 30.0%. The quality of the black garlic milk jam was evaluated on the color, pH, total acidity, total polyphenol content, total flavonoid content, and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity. In color, lightness (L) and yellowness (b) of the milk jam samples decreased with increasing black garlic extract levels, whereas redness (a) increased. At higher black garlic extract levels, the pH of black garlic milk jam decreased from 6.46±0.07 to 5.44±0.01, and its total acidity increased from 0.277±0.037% to 0.399±0.026%. The total polyphenol and total flavonoid contents of black garlic milk jam ranged from 144.76±3.51 to 263.41±2.34 mg GAE/100 g and 24.29±1.31 to 44.81±0.35 mg QE/100 g, respectively. These values increased significantly (p

Background: In Korea, laws for many medical technicians were revised in the Enforcement Decree of the Medical Technicians Act (MTA), which was announced on December 2018, whereas those related to dental hygienists remained unchanged. This study aimed to determine the awareness and opinions of dental hygienists regarding MTA.Methods: Dental hygienist were recruited as participants via convenient sampling in Seoul, Gyeonggi-do, and Chungcheong-do; data from 291 self-reported questionnaire responses were used for the final analysis. We investigated the participants’ general characteristics, awareness, and request for the amendment of the MTA. The compliance with the work scope specified in the MTA and level of demand for revision of the MTA were analyzed by independent t-test and one-way analysis of variance. For all statistical analyses, the significance level was set at 0.05.Results: For the 2018 MTA revision, 99 (34.02%) knew that dental treatment assistance and surgery assistance were excluded, whereas 192 (65.98%) did not know. The item “The current medical technician law must be revised” was scored 4.13±0.80 out of 5 points, and significant differences were identified according to the education level, career, and position (p＜0.05). The item “It is necessary to institutionalize the expanded work scope beyond the work scope of dental hygienists specified in the MTA” was scored 4.02±1.04 out of 5 points, and significant differences were identified according to age (p＜0.05).Conclusion: The participants wanted the MTA to be revised to reflect the real-world work performed by dental hygienists in the dental clinical field. The legal system must ensure the legal protection of the work area of the dental hygienist as an oral health professional, and recognize the legal work scope of the dental hygienist.

Garlic peel has been found to have various beneficial effects including antioxidant activities, antithrombosis activities and cancer inhibition. This study was to analyze the quality characteristics and antioxidant activities of garlic peel processed using different methods (control, roasting, steaming, roasting after steaming and blanching) to determine the most appropriate processing method for garlic peel to be used as a functional food ingredient. The lightness color values was highest in the control group, redness was highest in the roasting after steaming group, and yellowness was highest in the roasting group. The total pyruvate content of the roasting after steaming group garlic peel was 37.05 mg/100 g, which was higher than those of the other groups. The total polyphenol and total flavonoid contents of garlic peel ranged 47.60 to 172.53 mg/100 g and 3.43 to 17.63 mg/100 g, respectively. The highest total polyphenol content and total flavonoid content were observed for the roasting after steaming group. 2,2-Diphenyl-1-picrylhydrazyl radical scavenging activity was also the highest in the roasting after steaming group (81.28%). These results indicate that the method used to process garlic peel affects its quality, and that roasting after steaming is the most appropriate processing method, as it achieves the highest antioxidant activity.

The incidence of work-related musculoskeletal disorders (MSDs) among dental workers has been increasing. Many ergonomic devices and accessories have been introduced. The aim of this study was to investigate the effects of an 8-figure shoulder brace on posture-related muscle activities in dental hygiene practitioners during scaling procedures. In this study, 33 participants (age: 21.9 &plusmn, 2.1 years, height: 162.0 &plusmn, 6.0 cm, weight: 55.8 &plusmn, 9.0 kg, body mass index: 21.2 &plusmn, 2.4 kg/m2) performed the scaling procedure with and without the 8-figure shoulder brace in a randomized order. The normalized electromyography activity in the amplitude probability distribution function and joint angles (cervical, thoracic, lumbar, and shoulder joints) were simultaneously recorded during scaling. A paired t test was used to compare the differences in muscle kinematics, with the alpha level set at 0.05. The dental hygienists who wore the 8-figure shoulder brace during scaling showed thoracic and lumbar extension, improved sitting postures, and reduced shoulder joint abduction. However, we also observed an unintended increase in internal rotation. Use of the 8-figure shoulder brace could prevent work-related MSDs in lumbar and thoracic regions by reducing the effort exerted by the upper trapezius and deltoid muscles, despite the increased muscular effort of the cervical erector spinae.

Magnetite (Fe3O4)-gold (Au) core-shell nanoparticles (NPs) have unique magnetic and optical properties. When combined with biological moieties, these NPs can offer new strategies for biomedical applications, such as drug delivery and cancer targeting. Here, we present an effective method for the controllable cellular uptake of magnetic core-shell NP systems combined with biological moieties. Vimentin, which is the structural protein, has been biochemically confirmed to affect phagocytosis potently. In addition, vimentin affects exogenic materials internalization into cells even though under multiple inhibitions of biological moieties. In this study, we demonstrate the cellular internalization performance of Fe3O4-Au core-shell NPs with surface modification using a combination of biological moieties. The photofluorescence of vimentin-tagged NPs remained unaffected under multiple inhibition tests, indicating that the NPs were minimally influenced by nystatin, dynasore, cytochalasin D, and even the Muc1 antibody (Ab). Consequently, this result indicates that the Muc1 Ab can target specific molecules and can control specific endocytosis. Besides, we show the possibility of controlling specific endocytosis in colorectal cancer cells.

Nanostructures organized in unordinary spatial arrangements with multiple components such as core–shell configurations endow structures, material properties and functions that differ from the individual bulk components. In this study, we report the synthesis and characterization of bifunctional magnetic–luminescent Fe3O4–CdSe core–shell nanocrystals with core diameter and shell thickness of 10 and 2 nm, respectively, by controlled sequential reactions. The nanocrystals exhibit well-defined superparamagnetic behavior with high susceptibility at RT. Moreover, the fluorescent measurements demonstrate two major kinds of emission peaks, one at 572 nm originating from the bandgap excitons and the other at 680 nm being surface-associated. These core–shell nanocrystals, coupling the optical sensing element with the magnetic actuator in a peculiar nanostructure are thereby prospected for fundamental study and various applications where multifunctionality is required.

Background Some beverages are known to cause extrinsic staining on the tooth. This study investigated the degree of pigmentation caused by children's acidic beverages, and to confirm the possibility of the quantitative light-induced fluorescence (QLF) technology in assessing staining of the tooth. Methods Bovine tooth specimens were subjected to an 8-day pH-cycling model, using six children's beverages (experimental groups) and a cola (control group), and a remineralizing solution. Before and after the pH-cycling, white-light and fluorescence images of the enamel surface were photographed with a QLF to evaluate color change (ΔEafter) and fluorescence loss (ΔFafter), respectively. Paired t-test was used to compare the tooth colors obtained before and after the pH-cycling. Spearman correlation analysis was performed to examine the correlation between the ΔEafter and ΔFafter values. Results Median ΔEafter values of all the beverages ranged from 1.33 to 20.42, showing the greatest value in Koal-Koal Koala™ (KKK, p Conclusions The cola and 6 children’s beverages showed the possibility for discoloration on the tooth. The QLF technology may enable monitoring the discoloration induced on the tooth surface by acidic beverage.

Reactive oxygen species (ROS) produced upon collagen stimulation are implicated in propagating various platelet-activating pathways. Among ROS-producing enzymes, NADPH oxidase (NOX) is largely responsible for collagen receptor-dependent ROS production. Therefore, NOX has been proposed as a novel target for the development of antiplatelet agent. We here investigate whether resveratrol inhibits collagen-induced NOX activation and further examine the effects of resveratrol on ROS-dependent signaling pathways in collagen-stimulated platelets. Collagen-induced superoxide anion production in platelets was inhibited by resveratrol. Resveratrol suppressed collagen-induced phosphorylation of p47(phox), a major regulatory subunit of NOX. Correlated with the inhibitory effects on NOX, resveratrol protected SH2 domain-containing protein tyrosine phosphatase-2 (SHP-2) from ROS-mediated inactivation and subsequently attenuated the specific tyrosine phosphorylation of key components (spleen tyrosine kinase, Vav1, Bruton's tyrosine kinase, and phospholipase Cγ2) for collagen receptor signaling cascades. Resveratrol also inhibited downstream responses such as cytosolic calcium elevation, P-selectin surface exposure, and integrin-αIIbβ3 activation. Furthermore, resveratrol inhibited platelet aggregation and adhesion in response to collagen. The antiplatelet effects of resveratrol through the inhibition of NOX-derived ROS production and subsequent oxidative inactivation of SHP-2 suggest that resveratrol is a potential compound for prevention and treatment of thrombovascular diseases.

Reactive oxygen species (ROS) generated upon collagen stimulation act as second messengers to propagate various platelet-activating events. Among the ROS-generating enzymes, NADPH oxidase (NOX) plays a prominent role in platelet activation. Thus, NOX has been suggested as a novel target for anti-platelet drug development. Although kaempferol has been identified as a NOX inhibitor, the influence of kaempferol on the activation of platelets and the underlying mechanism have never been investigated. Here, we studied the effects of kaempferol on NOX activation, ROS-dependent signaling pathways, and functional responses in collagen-stimulated platelets. Superoxide anion generation stimulated by collagen was significantly inhibited by kaempferol in a concentration-dependent manner. More importantly, kaempferol directly bound p47(phox), a major regulatory subunit of NOX, and significantly inhibited collagen-induced phosphorylation of p47(phox) and NOX activation. In accordance with the inhibition of NOX, ROS-dependent inactivation of SH2 domain-containing protein tyrosine phosphatase-2 (SHP-2) was potently protected by kaempferol. Subsequently, the specific tyrosine phosphorylation of key components (Syk, Vav1, Btk, and PLCγ2) of collagen receptor signaling pathways was suppressed by kaempferol. Kaempferol also attenuated downstream responses, including cytosolic calcium elevation, P-selectin surface exposure, and integrin-αIIbβ3 activation. Ultimately, kaempferol inhibited platelet aggregation and adhesion in response to collagen in vitro and prolonged in vivo thrombotic response in carotid arteries of mice. This study shows that kaempferol impairs collagen-induced platelet activation through inhibition of NOX-derived ROS production and subsequent oxidative inactivation of SHP-2. This effect suggests that kaempferol has therapeutic potential for the prevention and treatment of thrombovascular diseases.

Collagen-induced platelet signaling is mediated by binding to the primary receptor glycoprotein VI (GPVI). Reactive oxygen species produced in response to collagen have been found to be responsible for the propagation of GPVI signaling pathways in platelets. Therefore, it has been suggested that antioxidant enzymes could down-regulate GPVI-stimulated platelet activation. Although the antioxidant enzyme peroxiredoxin II (PrxII) has emerged as having a role in negatively regulating signaling through various receptors by eliminating H2O2 generated upon receptor stimulation, the function of PrxII in collagen-stimulated platelets is not known. We tested the hypothesis that PrxII negatively regulates collagen-stimulated platelet activation. We analyzed PrxII-deficient murine platelets. PrxII deficiency enhanced GPVI-mediated platelet activation through the defective elimination of H2O2 and the impaired protection of SH2 domain-containing tyrosine phosphatase 2 (SHP-2) against oxidative inactivation, which resulted in increased tyrosine phosphorylation of key components for the GPVI signaling cascade, including Syk, Btk, and phospholipase Cγ2. Interestingly, PrxII-mediated antioxidative protection of SHP-2 appeared to occur in the lipid rafts. PrxII-deficient platelets exhibited increased adhesion and aggregation upon collagen stimulation. Furthermore, in vivo experiments demonstrated that PrxII deficiency facilitated platelet-dependent thrombus formation in injured carotid arteries. This study reveals that PrxII functions as a protective antioxidant enzyme against collagen-stimulated platelet activation and platelet-dependent thrombosis. Background: Peroxiredoxin II (PrxII) functions as a negative regulator of cellular receptor signaling by efficiently eliminating H2O2 produced upon stimulation of receptors. Results: PrxII deficiency promotes GPVI-mediated platelet activation through oxidative inactivation of SH2 domain-containing tyrosine phosphatase 2. Conclusion: PrxII functions as a protective antioxidant against collagen-stimulated platelet activation and thrombosis. Significance: PrxII is a potential target in thrombovascular diseases.

Therapeutic cancer vaccines promote immune responses by delivering tumour-specific antigens. Recently, we developed iron oxide (Fe3O4)–zinc oxide (ZnO) core-shell nanoparticles (CSNPs) as carriers for antigen delivery into dendritic cells (DCs), and the CSNPs were injected subcutaneously into C57BL/6 mice to examine the systemic toxicity, tissue distribution and excretion of the CSNPs. The doses injected were 0, 4, 20 and 200 mg kg–1 weekly for 4 weeks. No significant changes were observed after the CSNPs administration with respect to mortality, clinical observations, body weight, food intake, water consumption, urinalysis, haematology, serum biochemistry,and organ weights. A dose-dependent increase in granulomatous inflammation was observed at the injection site of the CSNP-treated animals, but no other histopathological lesions in other organs could be attributed to the CSNPs. The Zn concentration, which is an indicator for CSNPs, was not significantly higher in the sampled tissues, urine, or faeces after the CSNP injection. In contrast, the Zn concentration at the subcutaneous skin of the site injected with the CSNPs increased in a dose-dependent manner, along with a macroscopic deposition of the CSNPs. The CSNP residue at the injection site resulted in a foreign body response with the appearance of macrophage infiltration, but otherwise did not show any systemic distribution or toxicity at up to 200 mg kg–1 during this study. In conclusion, CSNPs could be used as good antigen carriers for DC-based immunotherapy, although further study is needed to completely clear the residue of the CSNPs at the injection site. Copyright © 2015 John Wiley & Sons, Ltd.

Objective This study aimed to assess the reliability and validity of an inertial measurement unit (IMU)–based 3-dimensional (3D) angular measurement system for evaluating cervical range of motion. Methods Thirty-three healthy participants (21.9 ± 2.1 years; 162.0 ± 6.0 cm; 55.8 ± 9.0 kg; 21.2 ± 2.4 kg/m2) were evaluated. Kinematic data of the cervical joints were simultaneously obtained using the IMU 3D angular, goniometer, and photographic measurements during cervical flexion (0°, 30°, and 50°), extension (30°, 50°), side-bending (0°, 20°, 40°), and rotation (45°). Test–retest reliability was investigated in each measurement method. Concurrent validity was assessed with the direct comparison between the IMU 3D angular measurement and other methods. Results The IMU 3D angular measurement showed mostly good to high test–retest reliability with relatively small standard error of measurement and the minimal detectable change values. The concurrent validity of IMU 3D angular measurements in the cervical range of motion was mostly reasonable. However, the measurement bias between the 2 methods tended to be larger at the end range of each plane. Conclusion Using the IMU 3D angular measurement in cervical spine is recommended because of its mostly good to high reliability and reasonable validity. However, using the IMU 3D angular measurement at the end range of each plane should be carefully considered owing to the poorer validity.

Correspondence to: Ki-Rim KimDepartment of Dental Hygiene, Kyungpook National University, 2559, Gyeongsang-daero, Sangju 742-711, KoreaTel: +82-54-530-1422, Fax: +82-54-530-1429, E-mail: rim0804@knu.ac.kr*These two authors contributed equally to this work.Copyright © 2014 by the Korean Society of Dental Hygiene Science This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/ by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Objective: A low-viscosity resin (infiltrant) was used to inhibit the progression of white spot lesions (WSLs) and resolve associated esthetic issues. An alternative pretreatment was explored to increase the pore volume of the surface layer of the WSLs. Also, the penetration effects of the infiltrant were evaluated for various pretreatments. Methods: Sixty two artificial lesions were fabricated on bovine teeth. As a positive control, 15% HCl gel was applied for 120 seconds. Further, 37% H3PO4 gel was applied for 30 seconds using three methods. The samples were divided as follows: H3PO4 only group, H3PO4 sponge group, and H3PO4 brush group. The acid was gently rubbed with the applicators (i.e., a sponge or brush) throughout the application time. To compare the effects of resin infiltration, twenty paired halves of specimens were treated with an infiltrant (ICON®). Results: Thicknesses of the removed surface layers and infiltrated areas were evaluated by confocal laser scanning microscope. The positive control and the 37% H3PO4 brush group failed to show significant differences in the removed thickness (p > 0.05); however, the mean percentage of the infiltrated area was higher in the 37% H3PO4 brush group (84.13 ± 7.58%) than the positive control (63.51 ± 7.62%, p < 0.001). Scanning electron microscope observations indicate higher pore volumes for the 37% H3PO4 brush group than for the positive control. Conclusions: Application of 37% H3PO4 with a brush for 30 seconds increased the pore volume of WSL surface layers and the percentage of infiltrated areas in comparison to the use of 15% HCl for 120 seconds.

ObjectivesThis study evaluated whether coronary artery calcium scores (CACS) and the degree of stenosis that were measured with computed tomography coronary angiography (CTCA) predicted post-operative cardiovascular events in patients who were undergoing intermediate-risk noncardiac surgery.BackgroundCardiovascular complications are important causes of mortality and morbidity in patients undergoing major noncardiac surgeries.MethodsA total of 239 patients underwent CTCA before intermediate-risk noncardiac surgeries. We measured CACS and the degree of stenosis with CTCA and assessed clinical risk factors according to the revised cardiac risk index (RCRI) scores. Post-operative cardiovascular events were defined as cardiac death, acute coronary syndrome, pulmonary edema, ventricular arrhythmia with hemodynamic compromise, and complete heart block.ResultsNineteen patients (8%) had post-operative cardiac events. The variables that correlated with the occurrence of cardiac events were RCRI (p < 0.001), CACS (p < 0.001), the presence of significant coronary artery stenosis (diameter stenosis ≥50%) (p = 0.01), and multivessel coronary artery disease (p < 0.001). In the receiver-operating characteristic (ROC) curve analysis of CACS for prediction of cardiac events, the cutoff value was 113 (sensitivity, 0.79; specificity, 0.61; area under the curve, 0.762). When comparing ROC curves of the combination models of RCRI, high CACS (≥113), and the presence of multivessel disease, RCRI plus high CACS, RCRI plus multivessel disease, and RCRI plus high CACS plus multivessel disease were significantly more predictable of post-operative cardiovascular events than RCRI alone.ConclusionsIn the pre-operative risk stratification of patients who were undergoing intermediate-risk noncardiac surgeries, CTCA evaluations showed additive value to RCRI.

We report the tunable synthesis and multifunctionalities of Fe 3 O 4 –ZnO hybrid core-shell nanocrystals as prepared through controlled sequential nanoemulsion processes. The characterization shows the orderly variations of the structural, magnetic, photoluminescent and absorption properties of the nanocrystals versus the nanoshell thickness. The nanocrystals reveal structural features unique to the core-shell design and exhibit well-defined superparamagnetic behavior at room temperature. In opposite to the decreasing magnetization, both bandgap and induced surface emissions depend strongly on the increasing nanoshell thickness. Moreover, the FTIR analysis provides the fingerprints of the polymer surfactant, ZnO and Fe 3 O 4 in the same nano-entity and the core-shell nanocrystals could be directly dispersed in both aqueous and organic media for application readiness. Aptly tunable in nanostructures and thus optimized properties, this kind of monosized, high quality, and multifunctional core-shell nanocrystals could be of interest for fundamental studies and potential applications.

Objectives To determine whether quantitative light-induced fluorescence (QLF) technology can be used to classify the colour of teeth specimens before and after resin infiltration (RI) treatment, and calculate the correlation between the ΔF value and colour difference (ΔE) in fluorescence images of the specimens obtained using a QLF–digital (QLF-D) device. Methods Sixty sound bovine permanent teeth specimens were immersed in demineralized solution. Two exposed windows were formed in each specimen, and RI treatment was applied to one of them. The ΔE values were obtained for the differences between a sound tooth surface (SS), an early dental caries surface (ECS) and an ECS treated with RI (RS) in white-light and fluorescence images obtained using QLF-D, respectively. The ΔF value was obtained from fluorescence images using dedicated software for QLF-D. The mean differences between the ΔE values obtained from the white-light and fluorescence images were analyzed by paired t -test. Pearson correlation analysis and Bland-Altman plots were applied to the differences between the ΔF value for ECS (ΔF SS-ECS ) and the ΔE value between SS and ECS (ΔE SS-ECS ), and between the ΔF value for RS (ΔF SS-RS ) and the ΔE value between SS and RS (ΔE SS-RS ) in fluorescence images. Results The ΔE values obtained from fluorescence images were three times higher than the ΔE values obtained from white-light images (p SS-ECS and ΔF SS-ECS (r = −0.492, p SS-RS and ΔF SS-RS (r = −0.661, p Conclusion QLF technology can be used to confirm the presence of RI in teeth.

We report the one-pot synthesis of bifunctional Au–Fe3O4 hybrid core–shell nanoparticles by controlled sequential reactions. The core–shell nanostructure of the resultant nanoparticles is identified by XRD and TEM, which is further substantiated by the changes in the corresponding physical and chemical properties. The nanoparticles exhibit a well-shaped absorption band in the visible region with a remarkable red-shifting to ∼592 nm and show clear superparamagnetic behavior at room temperature along with enhanced susceptibility, demonstrating the integration of the optical and magnetic functions of the respective components in one entity. This kind of bifunctional optical-magnetic core–shell nanoparticles could be of interest in interfacial proximity effects due to the unique spatial nanostructure configuration and have potential applications in various areas.

This study examined the dental erosion and demineralization potential of a sports drink containing nano-sized hydroxyapatite (nano-HA) as an additive.The experimental solutions were Powerade (PA) alone and PA with 0.05%, 0.10%, and 0.25% nano-HA. The pH, titratable acidity, and calcium and phosphate content of each solution were analysed, and the degree of saturation with respect to the dental enamel (DS(En)) was obtained. Twelve sound bovine enamel specimens for each group were treated in accordance with the pH-cycling schedule which had 60min treatment with experimental solution per day for 7 days. The erosion potential was determined from the changes in surface micro hardness (SMH), the depths of erosion and demineralized layer using confocal laser scanning microscopy (CLSM), and the morphological changes to the tooth surface were examined with scanning electron microscopy (SEM) after pH-cycling.pH and DS(En) increased with increasing nano-HA concentration in the drinks, whereas the titratable acidity decreased. There were significant differences in the SMH between the PA alone and0.10% nano-HA groups (p0.001). Although the PA alone group showed a pronounced erosion depth, CLSM showed no erosion depth in 0.25% nano-HA group. SEM showed an intact surface with increasing nano-HA concentration in the drinks. In conclusion, dental erosion was effectively prevented with increase of adding concentration of nano-HA, and a sports drink containing 0.25% nano-HA might prevent dental erosion.

This paper describes the synthesis and magnetic properties of multifunctional Fe3O4-AuPt core-shell nanoparticles. The Fe3O4-AuPt core-shell nanoparticles were synthesized by a one-pot polyol process in two consecutive steps from Fe, Au, and Pt precursors. The structural characterization and property analysis proves the formation of the core-shell nanostructure fusing the multifunctionality in a single entity. The TEM observation shows that the Fe3O4-AuPt core-shell nanoparticles are highly crystalline and uniform in size distribution, with an averaged particle size of ~12.5 nm in diameter, whereas the X-ray diffraction patterns provide further substantiation. The surface plasmon resonance arising from the AuPt nano-shell was revealed by UV-vis spectroscopy, while the magnetic measurements by VSM and PPMS demonstrate the well-defined superparamagnetic and/or soft-ferromagnetic behavior of the Fe3O4-AuPt core-shell nanoparticles.

The stability of Sm 0.5 Sr 0.5 CoO 3 (SSC) under reduction conditions is investigated to determine whether it can be used as a cathode material in on-planar type, single-chamber, solid oxide fuel cells. The techniques of X-ray diffraction, X-ray photoelectron spectroscopy and scanning electron microscopy are used to reveal the reduction mechanism of SSC. Impedance spectroscopy analysis also provides a better understanding of the influence of decomposed SSC phases on cathode performance. Decomposition of SSC occurs on the surface by the formation of dot-shaped SrO, Co(OH) 2 and CoO on top of the reduced SSC layer at 250 °C in 4% H 2 O–96% H 2 . The SSC perovskite structure is destroyed at 350 °C in pure hydrogen. There is a catastrophic microstructural change in which SSC is completely decomposed to SrO and CoO that cover the surface of Sm 2 O 3 .