Plasma Surface Modification of 3Y-TZP at Low and Atmospheric Pressures with Different Treatment Times.

The efficiency of plasma surface modifications depends on the operating conditions. This study investigated the effect of chamber pressure and plasma exposure time on the surface properties of 3Y-TZP with N2/Ar gas. Plate-shaped zirconia specimens were randomly divided into two categories: vacuum plasma and atmospheric plasma. Each group was subdivided into five subgroups according to the treatment time: 1, 5, 10, 15, and 20 min. Following the plasma treatments, we characterized the surface properties, including wettability, chemical composition, crystal structure, surface morphology, and zeta potential. These were analyzed through various techniques, such as contact angle measurement, XPS, XRD, SEM, FIB, CLSM, and electrokinetic measurements. The atmospheric plasma treatments increased zirconia's electron donation (γ-) capacity, while the vacuum plasma treatments decreased γ- parameter with increasing times. The highest concentration of the basic hydroxyl OH(b) groups was identified after a 5 min exposure to atmospheric plasmas. With longer exposure times, the vacuum plasmas induce electrical damage. Both plasma systems increased the zeta potential of 3Y-TZP, showing positive values in a vacuum. In the atmosphere, the zeta potential rapidly increased after 1 min. Atmospheric plasma treatments would be beneficial for the adsorption of oxygen and nitrogen from ambient air and the generation of various active species on the zirconia surface.

Toxicity and Biodistribution of Fragmented Polypropylene Microplastics in ICR Mice.

Currently, polypropylene (PP) is used in various products, thus leading to high daily exposure in humans. Thus, it is necessary to evaluate the toxicological effects, biodistribution, and accumulation of PP microplastics in the human body. In this study, administration of two particle sizes of PP microplastics (approximately 5 and 10-50 µm) did not lead to any significant changes in several toxicological evaluation parameters, including body weight and pathological examination, compared with the control group in ICR mice. Therefore, the approximate lethal dose and no-observed-adverse-effect level of PP microplastics in ICR mice were established as ≥2000 mg/kg. Furthermore, we manufactured cyanine 5.5 carboxylic acid (Cy5.5-COOH)-labeled fragmented PP microplastics to monitor real-time in vivo biodistribution. After oral administration of the Cy5.5-COOH-labeled microplastics to the mice, most of the PP microplastics were detected in the gastrointestinal tract and observed to be out of the body after 24 h in IVIS Spectrum CT. Therefore, this study provides a new insight into the short-term toxicity, distribution, and accumulation of PP microplastics in mammals.

Nonsteroidal Anti-Inflammatory Drug Conjugated with Gadolinium (III) Complex as an Anti-Inflammatory MRI Agent.

Studies have been actively conducted to ensure that gadolinium-based contrast agents for magnetic resonance imaging (MRI) are accompanied by various biological functions. A new example is the anti-inflammatory theragnostic MRI agent to target inflammatory mediators for imaging diagnosis and to treat inflammatory diseases simultaneously. We designed, synthesized, and characterized a Gd complex of 1,4,7-tris(carboxymethylaza) cyclododecane-10-azaacetylamide (DO3A) conjugated with a nonsteroidal anti-inflammatory drug (NSAID) that exerts the innate therapeutic effect of NSAIDs and is also applicable in MRI diagnostics. Gd-DO3A-fen (0.1 mmol/kg) was intravenously injected into the turpentine oil-induced mouse model, with Gd-DO3A-BT as a control group. In the in vivo MRI experiment, the contrast-to-noise ratio (CNR) was higher and persisted longer than that with Gd-DO3A-BT; specifically, the CNR difference was almost five times at 2 h after injection. Gd-DO3A-fen had a binding affinity (Ka) of 6.68 × 106 M-1 for the COX-2 enzyme, which was 2.1-fold higher than that of fenbufen, the original NSAID. In vivo evaluation of anti-inflammatory activity was performed in two animal models. In the turpentine oil-induced model, the mRNA expression levels of inflammatory parameters such as COX-2, TNF-α, IL-1ß, and IL-6 were reduced, and in the carrageenan-induced edema model, swelling was suppressed by 72% and there was a 2.88-fold inhibition compared with the saline group. Correlation analysis between in vitro, in silico, and in vivo studies revealed that Gd-DO3A-fen acts as an anti-inflammatory theragnostic agent by directly binding to COX-2.

Effects of Uncertainty, Appraisal of Uncertainty, and Self-Efficacy on the Quality of Life of Elderly Patients with Lung Cancer Receiving Chemotherapy: Based on Mishel's Theory of Uncertainty.

Background and Objectives: The purpose of this study is to enhance the quality of life in elderly patients with lung cancer by understanding relations of uncertainty, appraisal of uncertainty, self-efficacy, and quality of life targeting elderly patients with lung cancer receiving anticancer therapy, and also analyzing the factors affecting the quality of life based on Mishel's theory. Materials and Methods: The subjects were a total of 112 lung cancer patients aged 65 or older receiving anticancer therapy. The data was collected by using self-report questionnaires targeting patients in hemato-oncology at Chungbuk National University Hospital. The data were analyzed using descriptive statistics, a t-test, an analysis of variance, Pearson's correlational coefficients, and hierarchical regression analysis. Results: In stage 1, anticancer therapy (chemotherapy) (ß = -0.34, p < 0.001), economic condition (low) (ß = -0.30, p < 0.001), the number of anticancer therapies (three times or more) (ß = -0.29, p < 0.001), and education (graduation from high school or higher) (ß = 0.18, p = 0.033) were influencing factors (F = 0.52, p < 0.001). In stage 2, self-efficacy (ß = 0.41, p < 0.001), appraisal of uncertainty: danger (ß = -0.29, p < 0.001), appraisal of uncertainty: opportunity (ß = 0.18, p = 0.018), the number of anticancer therapies (three times or more) (ß = -0.17, p = 0.006), and anticancer therapy (chemotherapy) (ß = -0.14, p = 0.031) were influencing factors, which showed 74.2% explanatory power (F = 26.17, p < 0.001). Conclusions: In order to improve the quality of life of subjects, it would be necessary to develop interventions for raising their self-efficacy by considering their degree of education, economic condition, the types and numbers of anticancer therapies, and understanding of the appraisal of uncertainty about the disease is assessed as an opportunity factor or a danger factor.

Thermodynamic Studies on the Hydrolysis of Trivalent Plutonium and Solubility of Pu(OH)3(am).

The temperature-dependent reaction properties of actinide elements are of particular interest in the safety assessment of high-level radioactive waste (HLRW) disposal systems. In this study, the hydrolysis of Pu(III) and the solubility of Pu(OH)3(am) were investigated at various temperatures (10-40 °C) in 0.1 M NaClO4. A strong reducing condition for maintaining the oxidation state of Pu(III) while slowly increasing the pH of the solution was realized by electrolysis. The formation constants of the first hydrolysis species, log *ß1', and the solubility products of Pu(OH)3(am), log *Ks,0', at 10, 17, and 40 °C were experimentally determined using spectrophotometry, laser-induced breakdown detection, and radiometry. The enthalpy and entropy changes for these reactions were estimated using the van't Hoff equation. The first hydrolysis of Pu(III) is endothermic (ΔrHm° = 34.10 ± 4.48 kJ mol-1), and the dissolution of Pu(OH)3(am) is exothermic (ΔrHm° = -294.29 ± 23.05 kJ mol-1) with negative entropy changes. These thermodynamic data will contribute to improving the reliability of the safety assessment of HLRW disposal facilities and understanding the geochemical behavior of Pu under reducing or anoxic aqueous conditions at elevated temperatures.

Thermodynamic Study of Am(III)-Isosaccharinate Complexation at Various Temperatures Implicating a Stepwise Reduction in Binding Denticity.

Isosaccharinic acid, a major final product of cellulose degradation under highly alkaline cement porewater conditions, is known to increase the mobility of actinides via strong complex formation. In this study, the formation of Am(III) complexes with α-d-isosaccharinate (ISA) was studied in terms of thermodynamics and coordination structures by combining spectrophotometry, time-resolved laser fluorescence spectroscopy (TRLFS), and density functional theory (DFT) calculations. The formation constants of the Am(III)-ISA complexes were determined by absorption spectroscopy at temperatures in the range of 15-70 °C. The measured reaction enthalpy and entropy changes indicate that the formation of a 1:1 Am(III)-ISA complex is driven by an increase in entropy. By contrast, the 1:2 complex formation is exothermic with a much less increase in entropy. DFT calculations predict that C2- and C4-hydroxyl groups, along with the carboxyl group, participate in the tridentate chelate binding of the primary ISA. The thermodynamic, TRLFS, and DFT results collectively suggest the tridentate binding of the primary ISA to Am(III) via a carboxylate and C2- and C4-hydroxyl groups in the protonated state and reduced dentate binding of the secondary ISA, such as bidentate binding, forming a four-membered ring structure via the carboxylate group.

Effect of the Plasma Gas Type on the Surface Characteristics of 3Y-TZP Ceramic.

Plasma surface treatment can be an attractive strategy for modifying the chemically inert nature of zirconia to improve its clinical performance. This study aimed to clarify the effect of plasma gas compositions on the physicochemical surface modifications of 3 mol% yttria-stabilized zirconia (3Y-TZP). The cold, atmospheric plasma discharges were carried out by using four different plasma gases, which are He/O2, N2/Ar, N2, and Ar from an application distance of 10 mm for 60 s. Static contact angles were measured to define the surface free energy. Changes in elemental composition, surface crystallinity, and surface topography were assessed with X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), confocal laser scanning microscopy (CLSM), and scanning electron microscopy (SEM), respectively. A significant decrease in water contact angle was observed in all plasma groups with the lowest value of 69° in the N2/Ar group. CLSM and SEM investigations exhibited no morphological changes in all plasma groups. XPS revealed that a reduction in the surface C content along with an increase in O content was pronounced in the case of N2/Ar compared to others, which was responsible for high hydrophilicity of the surface. XRD showed that the changes in crystallite size and microstrain due to oxygen atom displacements were observed in the N2/Ar group. The N2/Ar plasma treatment may contribute to enhancing the bioactivity as well as the bonding performance of 3Y-TZP by controlling the plasma-generated nitrogen functionalities.

Assessment of Various Density Functional Theory Methods for Finding Accurate Structures of Actinide Complexes.

Density functional theory (DFT) is a widely used computational method for predicting the physical and chemical properties of metals and organometals. As the number of electrons and orbitals in an atom increases, DFT calculations for actinide complexes become more demanding due to increased complexity. Moreover, reasonable levels of theory for calculating the structures of actinide complexes are not extensively studied. In this study, 38 calculations, based on various combinations, were performed on molecules containing two representative actinides to determine the optimal combination for predicting the geometries of actinide complexes. Among the 38 calculations, four optimal combinations were identified and compared with experimental data. The optimal combinations were applied to a more complicated and practical actinide compound, the uranyl complex (UO2(2,2'-(1E,1'E)-(2,2-dimethylpropane-1,3-dyl)bis(azanylylidene)(CH3OH)), for further confirmation. The corresponding optimal calculation combination provides a reasonable level of theory for accurately optimizing the structure of actinide complexes using DFT.

CT quantification of the heterogeneity of fibrosis boundaries in idiopathic pulmonary fibrosis.

OBJECTIVES: To quantify the heterogeneity of fibrosis boundaries in idiopathic pulmonary fibrosis (IPF) using the Gaussian curvature analysis for evaluating disease severity and predicting survival. METHODS: We retrospectively included 104 IPF patients and 52 controls who underwent baseline chest CT scans. Normal lungs below - 500 HU were segmented, and the boundary was three-dimensionally reconstructed using in-house software. Gaussian curvature analysis provided histogram features on the heterogeneity of the fibrosis boundary. We analyzed the correlations between histogram features and the gender-age-physiology (GAP) and CT fibrosis scores. We built a regression model to predict diffusing capacity of carbon monoxide (DLCO) using the histogram features and calculated the modified GAP (mGAP) score by replacing DLCO with the predicted DLCO. The performances of the GAP, CT-GAP, and mGAP scores were compared using 100 repeated random-split sets. RESULTS: Patients with moderate-to-severe IPF had more numerous Gaussian curvatures at the fibrosis boundary, lower uniformity, and lower 10th to 30th percentiles of Gaussian curvature than controls or patients with mild IPF (all p < 0.0033). The 20th percentile was most significantly correlated with the GAP score (r = - 0.357; p < 0.001) and the CT fibrosis score (r = - 0.343; p = 0.001). More numerous Gaussian curvatures, higher entropy, lower uniformity, and 10th to 30th percentiles (p < 0.001-0.041) were associated with mortality. The mGAP score was comparable to the GAP and CT-GAP scores for survival prediction (mean C-indices, 0.76 vs. 0.79 vs. 0.77, respectively). CONCLUSIONS: Gaussian curvatures of fibrosis boundaries became more heterogeneous as the disease progressed, and heterogeneity was negatively associated with survival in IPF. KEY POINTS: • Gaussian curvature of the fibrotic lung boundary was more heterogeneous in patients with moderate-to-severe IPF than those with mild IPF or normal controls. • The 20th percentile of the Gaussian curvature of the fibrosis boundary was linearly correlated with the GAP score and the CT fibrosis score. • A modified GAP score that replaced the diffusing capacity of carbon monoxide with a composite measure using histogram features of the Gaussian curvature of the fibrosis boundary showed a comparable ability to predict survival to both the GAP and the CT-GAP score.

Study of Aqueous Am(III)-Aliphatic Dicarboxylate Complexes: Coordination Mode-Dependent Optical Property and Stability Changes.

The thermodynamics of Am(III) complex formation in natural groundwater systems is one of the major topics of research in the field of high-level radioactive waste management. In this study, we investigate the absorption and luminescence properties of aqueous Am(III) complexes with a series of aliphatic dicarboxylates in order to learn the thermodynamic complexation behaviors in relation to binding geometries. The formation of Am(III) complexes with these carboxylate ligands induced distinct red shifts in the absorption spectra, which enabled chemical speciation. The formation constants determined by deconvolution of the absorption spectra showed a linear decrease for the three ligands (oxalate (Ox), malonate (Mal), and succinate (Suc)) and a mild decrease for the remaining ligands (glutarate (Glu) and adipate (Adi)). Time-resolved laser fluorescence spectroscopy (TRLFS) was used to obtain information about the aqua ligand, which indirectly indicated the bidentate bindings of these dicarboxylate ligands. A complementary attenuated total reflectance Fourier transform infrared (ATR-FTIR) study on Eu(III), which is a nonradioactive analogue of Am(III) ion, showed that the coordination modes differ depending on the alkyl chain length. Ox and Mal bind to Am(III) via side-on bidentate bindings with two carboxylate groups, resulting in the formation of stable 5- and 6-membered ring structures, respectively. On the other hand, Suc, Glu, and Adi form end-on bidentate bindings with a single carboxylate group, resulting in a 4-membered ring structure. Density functional theory calculations provided details about the bonding properties and supported the experimentally proposed coordination geometries. This study demonstrates that coordination mode-dependent changes in optical properties occur along with thermodynamic stability changes in Am(III)-dicarboxylate complexes.

EF-G catalyzed translocation dynamics in the presence of ribosomal frameshifting stimulatory signals.

Programmed -1 ribosomal frameshifting (-1PRF) is tightly regulated by messenger RNA (mRNA) sequences and structures in expressing two or more proteins with precise ratios from a single mRNA. Using single-molecule fluorescence resonance energy transfer (smFRET) between (Cy5)EF-G and (Cy3)tRNALys, we studied the translational elongation dynamics of -1PRF in the Escherichia coli dnaX gene, which contains three frameshifting signals: a slippery sequence (A AAA AAG), a Shine-Dalgarno (SD) sequence and a downstream hairpin. The frameshift promoting signals mostly impair the EF-G-catalyzed translocation step of the two tRNALys and the slippery codons from the A- and P- sites. The hairpin acts as a road block slowing the translocation rate. The upstream SD sequence together with the hairpin promotes dissociation of futile EF-G and thus causes multiple EF-G driven translocation attempts. A slippery sequence also helps dissociation of the EF-G by providing alternative base-pairing options. These results indicate that frameshifting takes place during the repetitive ribosomal conformational changes associated with EF-G dissociation upon unsuccessful translocation attempts of the second slippage codon from the A- to the P- sites.

Effect of hydrothermal aging on the optical properties of precolored dental monolithic zirconia ceramics.

STATEMENT OF PROBLEM: The long-term color stability of precolored monolithic zirconia has not been thoroughly investigated. PURPOSE: The purpose of this in vitro study was to evaluate the effect of hydrothermal aging on the optical properties, phase transformation, and surface topography of precolored monolithic zirconia ceramics. MATERIAL AND METHODS: Precolored monolithic zirconia specimens (17.0×17.0×1.5 mm, n=50) and lithium disilicate glass-ceramic specimens (16.0×16.0×1.5 mm, n=50) were artificially aged in an autoclave at 134°C under 0.2 MPa for 0, 1, 3, 5, or 10 hours (n=10). CIELab color parameters were obtained from spectral measurements. The translucency parameter (TP) and CIEDE2000 color differences (ΔE00) were calculated. The microstructural and surface properties were analyzed by X-ray diffraction (XRD), atomic force microscope (AFM), and scanning electron microscope (SEM). Data were analyzed with 2-way ANOVA and pairwise comparison (α=.05). RESULTS: Significant interactions were found between aging time and ceramic material on L*, a*, b*, and TP (P<.001) as follows: b* partial eta squared [ηp2]=0.689; L* ηp2=0.186; a* ηp2=0.176; and TP ηp2=0.137. The b* values significantly decreased after aging for zirconia (P<.001), whereas TP increased after aging for zirconia (P<.014) except at 10 hours (P=.389) and for lithium disilicate (P<.001). The ΔE00 values relative to baseline ranged from 2.03 to 2.52 for aged zirconia and from 0.07 to 0.23 for aged lithium disilicate. XRD analysis revealed that hydrothermal aging promoted an increase in m-phase contents. AFM and SEM demonstrated surface alterations after aging. CONCLUSIONS: Optical properties and microstructures of precolored monolithic zirconia ceramics were affected by hydrothermal aging, and translucency increased slightly with aging time.

Synthesis and Evaluation of Manganese(II)-Based Ethylenediaminetetraacetic Acid-Ethoxybenzyl Conjugate as a Highly Stable Hepatobiliary Magnetic Resonance Imaging Contrast Agent.

In this study, we designed and synthesized a highly stable manganese (Mn2+)-based hepatobiliary complex by tethering an ethoxybenzyl (EOB) moiety with an ethylenediaminetetraacetic acid (EDTA) coordination cage as an alternative to the well-established hepatobiliary gadolinium (Gd3+) chelates and evaluated its usage as a T1 hepatobiliary magnetic resonance imaging (MRI) contrast agent (CA). This new complex exhibits higher r1 relaxivity (2.3 mM-1 s-1) than clinically approved Mn2+-based hepatobiliary complex Mn-DPDP (1.6 mM-1 s-1) at 1.5 T. Mn-EDTA-EOB shows much higher kinetic inertness than that of clinically approved Gd3+-based hepatobiliary MRI CAs, such as Gd-DTPA-EOB and Gd-BOPTA. In addition, in vivo biodistribution and MRI enhancement patterns of this new Mn2+ chelate are comparable to those of Gd3+-based hepatobiliary MRI CAs. The diagnostic efficacy of the new complex was demonstrated by its enhanced tumor detection sensitivity in a liver cancer model using in vivo MRI.

Radiometallic Complexes of DO3A-Benzothiazole Aniline for Nuclear Medicine Theranostics.

To develop a radioactive metal complex platform for tumor theranostics, we introduced three radiopharmaceutical derivatives of 1,4,7,10-tetraazacyclododecane-1,4,7-trisacetic acid-benzothiazole aniline (DO3A-BTA, L1) labeled with medical radioisotopes for diagnosis (68Ga/64Cu) and therapy (177Lu). The tumor-targeting ability of these complexes was demonstrated in a cellular uptake experiment, in which 177Lu-L1 exhibited markedly higher uptake in HeLa cells than the 177Lu-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid complex. According to in vivo positron emission tomography imaging, high accumulation of 68Ga-L1 and 64Cu-L1 was clearly visualized in the tumor site, while 177Lu-L1 showed therapeutic efficacy in therapy experiments. Consequently, this molecular platform represents a useful approach in nuclear medicine toward tumor-theranostic radiopharmaceuticals when 68Ga-L1 or 64Cu-L1 is used for diagnosis, 177Lu-L1 is used for therapy, or two of the compounds are used in conjunction with each other.

A study on the color distribution of natural teeth by age and gender in the Korean population with an intraoral spectrophotometer.

OBJECTIVE: To investigate the distribution of natural tooth shades by age and gender in the Korean population with a spectrophotometer. MATERIAL AND METHODS: A total of 674 human subjects were recruited and divided into three age groups; young (16-30), middle (31-59), and elderly (60-89). Each group was then subdivided according to gender. Color was measured on the upper central incisor and CIELab color coordinates were obtained. CIEDE2000 color differences ( ΔE00 ) between genders within each age group and between age groups for both genders were calculated. Two-way analysis of variance (ANOVA) was used to identify the influence of age and gender on each color variable. RESULTS: The most frequent color in the Korean population was 2L1.5. L* values decreased, while b* values increased with age (P < .05). There was a significant interaction between gender and age on b* values; F (2668) = 3.489, P = .031, partial η2 = 0.010, and observed power = 0.652. Females generally have lighter and less chromatic central incisors compared to males. The ΔE00 values between genders in elderly groups were beyond acceptability threshold. CONCLUSIONS: The central incisors were getting darker, more yellowish, and reddish with age. Information on the chromatic range of natural teeth by age and gender could help to select colors for esthetic dental restorations. CLINICAL SIGNIFICANCE: Dentists should consider an unacceptable color mismatch between the restorations and natural dentition that can occur over time.

A frameshifting stimulatory stem loop destabilizes the hybrid state and impedes ribosomal translocation.

Ribosomal frameshifting occurs when a ribosome slips a few nucleotides on an mRNA and generates a new sequence of amino acids. Programmed -1 ribosomal frameshifting (-1PRF) is used in various systems to express two or more proteins from a single mRNA at precisely regulated levels. We used single-molecule fluorescence resonance energy transfer (smFRET) to study the dynamics of -1PRF in the Escherichia coli dnaX gene. The frameshifting mRNA (FSmRNA) contained the frameshifting signals: a Shine-Dalgarno sequence, a slippery sequence, and a downstream stem loop. The dynamics of ribosomal complexes translating through the slippery sequence were characterized using smFRET between the Cy3-labeled L1 stalk of the large ribosomal subunit and a Cy5-labeled tRNA(Lys) in the ribosomal peptidyl-tRNA-binding (P) site. We observed significantly slower elongation factor G (EF-G)-catalyzed translocation through the slippery sequence of FSmRNA in comparison with an mRNA lacking the stem loop, ΔSL. Furthermore, the P-site tRNA/L1 stalk of FSmRNA-programmed pretranslocation (PRE) ribosomal complexes exhibited multiple fluctuations between the classical/open and hybrid/closed states, respectively, in the presence of EF-G before translocation, in contrast with ΔSL-programmed PRE complexes, which sampled the hybrid/closed state approximately once before undergoing translocation. Quantitative analysis showed that the stimulatory stem loop destabilizes the hybrid state and elevates the energy barriers corresponding to subsequent substeps of translocation. The shift of the FSmRNA-programmed PRE complex equilibrium toward the classical/open state and toward states that favor EF-G dissociation apparently allows the PRE complex to explore alternative translocation pathways such as -1PRF.

Evaluation of Chewing Movement in Skeletal Class III Patients with Orthognathic Treatment.

The objective of this study was to clarify the influence of improvement in morphology on chewing movement in patients with skeletal reversed occlusion following orthognathic treatment. A total of 10 patients with skeletal class III reversed occlusion undergoing orthognathic treatment were included in the study. A number of parameters, including chewing rhythm, maximum opening and closing velocities, and opening distance during chewing of gum, were measured in a pre- (Pre) and post-treatment (Post) group. The laterality and stability of the measured items were then compared between the two groups and with those in another group of subjects with normal occlusion (Control). Laterality of chewing movement was greater in the Pre group than in the Control group, and significant differences were noted in all parameters, apart from closing Vmax and opening distance. No significant difference was noted in any parameter between the Post and Control groups. The coefficient of variation was significantly higher in the Pre group than in the Control group, apart from for opening phase. All parameters showed a significant decrease in the Post group compared with in the Pre group, yielding a stable chewing movement. Comparison of the Post and Control groups revealed no significant difference in any of the parameters, apart from in the occluding phase. These findings suggest that orthognathic treatment of skeletal class III malocclusion improves chewing movement to levels close to those in subjects with normal occlusion.

Intramolecular Hydrogen Bonding Restricts Gd-Aqua-Ligand Dynamics.

Aqua ligands can undergo rapid internal rotation about the M-O bond. For magnetic resonance contrast agents, this rotation results in diminished relaxivity. Herein, we show that an intramolecular hydrogen bond to the aqua ligand can reduce this internal rotation and increase relaxivity. Molecular modeling was used to design a series of four Gd complexes capable of forming an intramolecular H-bond to the coordinated water ligand, and these complexes had anomalously high relaxivities compared to similar complexes lacking a H-bond acceptor. Molecular dynamics simulations supported the formation of a stable intramolecular H-bond, while alternative hypotheses that could explain the higher relaxivity were systematically ruled out. Intramolecular H-bonding represents a useful strategy to limit internal water rotational motion and increase relaxivity of Gd complexes.

Effects of surface treatments on the translucency, opalescence, and surface texture of dental monolithic zirconia ceramics.

STATEMENT OF PROBLEM: Surface polishing or glazing may increase the appearance of depth of monolithic zirconia restorations. PURPOSE: The purpose of this in vitro study was to investigate the effects of surface treatments on the translucency, opalescence, and surface texture of dental monolithic zirconia ceramics. MATERIAL AND METHODS: Forty-five monolithic zirconia specimens (16.3×16.4×2.0 mm) were divided into groups I to V, according to the number of colorings each received. Each group was then divided into 3 subgroups (n=3) according to the surface treatment: N=no treatment; P=polished; and G=glazed. CIElab color coordinates were obtained relative to D65 on a reflection spectrophotometer. The translucency parameter (TP) and opalescence parameter (OP) were calculated. One specimen per subgroups I and V was selected for evaluation of surface roughness (Ra) and was examined with scanning electron microscopy (SEM). Data were analyzed with 2-way ANOVA and pairwise comparisons (α=.05). Statistical powers were verified to evaluate results (α=.05). RESULTS: The interaction effects of surface treatments combined with the number of colorings were significant for TP, OP, and Ra (P<.001), as follows: Ra=partial eta squared [ηp(2)]=.928; OP ηp(2)=.184; and TP ηp(2)=.144. No significant differences between TP were found among surface treatments in most groups (P>.05), whereas glazing significantly decreased OP and Ra in most groups. SEM images demonstrated that surface treatments affected the surface texture of monolithic zirconia ceramics. CONCLUSIONS: Surface treatments combined with coloring strongly affect the surface texture of dental monolithic zirconia ceramics.

Determinants of Quality of Life (QoL) in Female Caregivers in Elderly Care Facilities in Korea.

BACKGROUND: The purpose of this study was to analyze the effects of general characteristics, fatigue, depression, self-efficacy, job stress and interpersonal relationships on the quality of life (QoL) of caregivers in nursing hospitals and use them as basic data for intervention programs to improve the quality of life of caregivers. METHODS: The participants in the study were 137 caregivers, aged 52-76, who were actively working in nursing hospitals. Data were collected from caregivers by visiting 9 hospitals in 6 cities, with a questionnaire of fatigue, depression, self-efficacy, job stress, interpersonal relationship, quality of life. RESULTS: Age, marriage, marital satisfaction, education, education experience of QoL, monthly income, perceived economic status, hobby or leisure activity, and number of disease showed differences in the degree of QoL at a statistically significant level. In stage 1, economic status (ß = -0.18, p = 0.033) and hobby or leisure activity (ß = 0.19, p = 0.025) were influencing factors (F = 4.58, p < 0.001). In stage 2, monthly income (ß = -0.19, p = 0.034) and perceived economic status (ß = -0.18, p = 0.035) were influencing factors. In stage 3, age (ß = -2.80, p = 0.006), perceived economic status (ß = -2.41, p = 0.017), self-efficacy (ß = 3.19, p = 0.002) and interpersonal relationship (ß = 7.12, p < 0.001) were influencing factors which showed 61.5% explanatory power (F = 12.88, p < 0.001). Since the subject's fatigue, depression, and stress did not affect the quality of life, further research is needed. CONCLUSIONS: In order to improve the quality of life of caregivers, it would be necessary to develop interventions for raising their self-efficacy and interpersonal relationship by considering their degree of economic status, hobby or leisure activity, monthly income, and age.