A moderated mediation investigation of the influence of enterprise social media visibility on work stress.

Drawing upon the communication visibility theory, this study delves into the intricate dynamics of message transference and network translucence within the context of enterprise social media (ESM), unraveling their profound impact on information overload and social overload experienced by employees. Consequently, we examine the consequential relationship between these overwhelming cognitive burdens and the levels of work stress experienced by individuals in the organizational setting. Moreover, our study explores the moderating role of resilience, shedding light on how this intrinsic psychological trait can shape the connection among information overload, social overload, and work stress. Based on empirical analysis of the data collected from 351 ESM users, the findings demonstrate a significant positive association between message transference, network translucence, and the occurrence of information overload and social overload among employees. Furthermore, the results reveal a strong positive association among information overload and social overload over work stress. However, the salient contribution of this study lies in uncovering the pivotal moderating effect of resilience, revealing that high levels of resilience act as a buffer against the adverse impacts of information overload and social overload, leading to lower levels of work stress among individuals. By advancing our comprehension of communication visibility theory, this study adds to the theoretical underpinnings of communication visibility, resilience, and their interplay in the context of ESM while providing practical insights for employees and organizations to navigate the challenges posed by information overload, social overload, and work stress. Through its meticulous examination of these multifaceted phenomena, this study opens avenues for further research and invites scholars to probe deeper into the complex dynamics of communication visibility and resilience in the evolving landscape of contemporary organizations.

Mechanical Properties of Nanohybrid Resin Composites Containing Various Mass Fractions of Modified Zirconia Particles.

PURPOSE: The aim of this study was to investigate the effect of various mass fractions of 10-methacry-loyloxydecyl dihydrogen phosphate (MDP)-conditioned or unconditioned zirconia nano- or micro-particles with different initiator systems on the mechanical properties of nanohybrid resin composites. METHODS: Both light-cured (L) and dual-cured (D) resin composites were prepared. When the mass fraction of the nano- or micro-zirconia fillers reached 55 wt%, resin composites were equipped with dual-cured initiator systems. We measured the three-point bending-strength, elastic modulus, Weibull modulus and translucency parameter of the nanohybrid resin composites containing various mass fractions of MDP-conditioned or unconditioned zirconia nano- or micro-particles (0%, 5 wt%, 10 wt%, 20 wt%, 30 wt% and 55 wt%). A Cell Counting Kit (CCK)-8 was used to test the cell cytotoxicity of the experimental resin composites. The zirconia nano- or micro-particles with MDP-conditioning or not were characterized by transmission electron microscopy (TEM), Fourier infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). RESULTS: Resin composites containing 5-20 wt% MDP-conditioned or unconditioned nano-zirconia fillers exhibited better three-point bending-strength than the control group without zirconia fillers. Nano- or micro-zirconia fillers decreased the translucence of the nanohybrid resin composites. According to the cytotoxicity classification, all of the nano- or micro-zirconia fillers containing experimental resin composites were considered to have no significant cell cytotoxicity. The FTIR spectra of the conditioned nano- or micro-fillers showed new absorption bands at 1719 cm-1 and 1637 cm-1, indicating the successful combination of MDP and zirconia particles. The XPS analysis measured Zr-O-P peak area on MDP-conditioned nano- and micro-zirconia fillers at 39.91% and 34.89%, respectively. CONCLUSION: Nano-zirconia filler improved the mechanical properties of nanohybrid resin composites, but cannot be the main filler to replace silica filler. The experimental dual-cured composites can be resin cements with better opacity effects and a low viscosity.

Effect of hydrothermal aging on the properties of zirconia with different levels of translucency.

OBJECTIVES: The aim of this study was to evaluate the effect of hydrothermal aging on the mechanical properties and translucency of dental zirconia with different levels of translucency. METHODS: Three different types of dental yttria-stabilized zirconia were used: 3Y-TZP (ZrO2 - 3 mol.% Y2O3) of medium opacity (designated Z3OP), 3Y-TZP of medium translucency (Z3MT), and 5Y-PSZ (ZrO2 - 5 mol.% Y2O3) of high translucency (Z5HT). A total of 120 specimens were sintered (n = 40 specimens/group). The control group (sintered→polished→heat-treated) and the aged group (sintered→polished→heat-treated→hydrothermally degraded at 134 °C, 2 bar, 5h) were characterized by relative density, quantitative phase analysis by X-ray diffraction using the Rietveld method, microstructural analysis by scanning electron microscopy, surface roughness and translucency. All groups were submitted to a biaxial flexural strength test. Data analysis using Kruskal-Wallis, Nemenyi (p-value = 0.05), and Weibull statistics were used. RESULTS: All sintered specimens presented full densification. After aging, an increase of the m-ZrO2 phase content was observed for the Z3OP group. On the other hand, Z3MT and Z5HT did not show any m-ZrO2 phase, indicating resistance to the hydrothermal degradation. Smaller grains were observed in the Z3MT group in relation to Z3OP group and the Z5HT group presented a bimodal grain distribution, where the largest grains were associated to cubic ZrO2. Z3OP exhibited a slight increase in roughness as a function of degradation, while the roughness remained statistically stable in the other groups. Translucency was little influenced by degradation, but considerably affected by increasing thickness. The Z5HT samples were the group with the highest translucency among the control groups. Z3OP exhibited the highest flexural strength, while being the most susceptible to hydrothermal degradation. The lowest values were presented by Z5HT in all groups, due to the high concentration of c-ZrO2 grains. CONCLUSION: Hydrothermal aging is less critical to the flexural strength of zirconia-based materials than the materials' composition and microstructure. Z5HT zirconia showed the highest translucency, however the measured difference is not visually perceptible. Z5HT was considered the most resistant to hydrothermal degradation.

Translucence perception is not dependent on cortical areas critical for processing colour or texture.

Translucence is an important property of natural materials, and human observers are adept at perceiving changes in translucence. Perceptions of different material properties appear to arise from different cortical regions, and it is therefore plausible that the perception of translucence is dependent on specialised regions, separate from those important for colour and texture processing. To test for anatomical independence between areas necessary for colour, texture and translucence perception we assessed translucency perception in a cortically colour blind observer, who performs at chance on tasks of colour and texture discrimination. Firstly, in order to establish that MS has shown no significant recovery, we assessed his colour perception performance on the Farnsworth-Munsell 100 Hue Test. Secondly, we tested him with two translucence ranking tasks. In one task, stimuli were images of glasses of tea varying in tea strength. In the other, stimuli were glasses of tea varying only in milkiness. MS was able to systematically rank both strength and milkiness, although less consistently than controls, and for tea strength his rankings were in the opposite order. An additional group of controls tested with greyscale versions of the images succeeded at the tasks, albeit slightly less consistently on the milkiness task, showing that the performance of normal observers cannot be transformed into the performance of MS simply by removing colour information from the stimuli. The systematic performance of MS suggests that some aspects of translucence perception do not depend on regions critical for colour and texture processing.

Influence of light-curing on the translucence change and color stability of amine-free dual-cured resin cements / 대한치과재료학회지

The aim of this study was to investigate the influence of light-curing on the translucency change and color-stability of amine(tertiary)-free dual-cured resin cements after accelerated aging. Two curing modes (dual-curing and self-curing) were applied on three dual-cured resin cements (Duo-Link Universal [DLU], Nexus Third Generation [NX3] and RelyX Ultimate [RXU]) in this study. Ten specimens were fabricated for each group. In dual-cured groups only, light-activation was performed with polywave-LED curing unit (Bluphase, Ivoclar Vivadent, Schaan, Liechtenstein), where each sides of the samples were photo-polymerized for 60 seconds. Self-cured groups were kept in the dark storage for 24 hours. The color of the specimens was measured with spectrocolorimeter (NF999, Nippon Denshoku, Japan) after 24 hours of making samples. After the initial color measurements, the specimens were subjected to accelerated aging procedure. Spectrophotometric analysis was carried out on day 7, day 14, day 21 and day 28 of accelerated aging in 60 ℃ of distilled water. The color characteristics, color difference (ΔE*), and translucency parameter (TP) of specimens were calculated according to the CIE L*a*b* color system before and after aging. All the ΔE* values and TP values were analyzed by 2-way analysis of variance. After aging, all groups revealed clinically perceptible color differences (ΔE*>3.3). Differences in ΔE* values of self-cured groups were significantly higher than those of dual-cured groups in NX3 and RXU. But there were no significant differences in ΔE* between dual-cured mode and self-cured mode of DLU. All mean b* values increased after aging. All mean L* values decreased after aging except for self-cured RXU cement. TP values also decreased with aging. TP values of self-cured groups were significantly lower than those of dual-cured groups in NX3 and RXU. Hence, in conclusion, despite the absence of tertiary amine in the dual-cured resin cements, such resin cements should be polymerized with the dual-cure modes to ensure long-term color-stability.

Multichromatic and highly translucent hybrid ceramic Vita Enamic.

Vita Enamic is a durable hybrid ceramic that can be processed with efficient computer-aided design/computer-aided manufacturing (CAD/CAM) support. The porous sintered feldspar ceramic block that is infiltrated with polymer does not require a ceramic furnace after being ground out. Instead, it only needs to be finished and polished. This makes one-time chairside treatment possible. In addition to the well-known monochromatic Vita Enamic blocks, a multichromatic version with integrated shade gradient and a super-translucent version have been developed. The goal of this application study is to demonstrate these new indications with their material benefits in the anterior and posterior regions using four different case studies.

Study of the influence of pigments in the polymerization and mechanical performance of commercial dental composites / Estudo sobre a influência dos pigmentos na polimerização e no desempenho mecânico dos compósitos dentais comerciais

Objective: The aim of this study was to analyze the influence of the amount of shade pigment and opacifying components inthe polymerization and mechanical properties in two brands of Brazilian dental resin composites. Material and Methods: Master Fill microhybrid resin for enamel (colorless and shades A2, A4), and Opallis for enamel and dentine, both shades A2. Thecomposite resins were photopolymerized by a LED device at 19.7 J. The mechanical properties were obtained through flexuralresistance (FR), compression strength (CS) and Vickers microhardness (VM); the degree of conversion (DC) was obtainedby FTIR and translucence was obtained by sphere espectrometer. Conclusion: The analysis indicated that resin with more colorpigments (MA4) or more opacity components (ODA2) hadlow polymerization and poor mechanical properties than clearer(M) or more translucent (OEA2) resins, indicating that betterperformance can be obtained by increasing the radiation dose.

Objetivo: O objetivo deste estudo era analisar a influênciada quantidade de pigmentos de cor e de componentes opacificantesna polimerização e nas propriedades mecânicas em duasmarcas Brasileiras de resinas compostas dentárias. Material e Métodos: Resina Master Fill, microhíbrida, para esmalte (incolore nas cores A2 e A4) e Opallis para esmalte e dentina, ambas na cor A2. As resinas foram fotoativadas por um aparelho diodo emissor de luz (LED) a 19.7 J. As propriedades mecânicas foram obtidas por resistência flexural, força de compressão, microdureza Vickers; o grau de conversão foi obtido por FTIR e a translucidez foi obtida por meio do Espectrômetro de Esfera. Conclusões: As análises indicaram que resinas com mais pigmentos decor (MA4) ou mais componentes opacificantes (ODA2) mostrarambaixa polimerização e pobre qualidade mecânica quandocomparadas às mais claras e/ou mais translúcidas, indicando que a dose de irradiação deve ser aumentada para obter melhor performance.

Comparación de cribado combinado (ecográfico y bioquímico) de cromosomopatías en el primer y segundo trimestre de gestación en el hospital Teodoro Maldonado Carbo, Guayaquil – Ecuador / Combined cribation (echographic and biochemical) comparison of chromosomal pathologies in pregnancy first and second quarters in Teodoro Maldonado Carbo hospital, Guayaquil – Ecuador

Tipo de estudio: prospectivo, observacional, longitudinal. Objetivo general: comparar los hallazgos ecográficos con los del triple test como métodos de tamizaje para diagnóstico prenatal en mujeres de alto riesgo. Metodología: pacientes gestantes escogidas al azar ≥ 35 años atendidas en el área materno infantil del hospital “Teodoro Maldonado Carbo” del IESS, durante el período comprendido entre diciembre 2006 a mayo de 2007. Se les realizó a las 11-14 semanas de gestación (SG) el tamizaje ecográfico para cromosomopatías. Durante las 15 - 20 semanas el estudio bioquímico (triple test) en el laboratorio Medilabsa. A las 18 – 22 SG se les repitió el tamizaje ecográfico para cromosomopatías para confirmar resultados. Resultados: de las 31 pacientes valorados los productos obtenidos fueron: un aborto espontáneo a las 16.4 SG, (3.22); dos pacientes presentaron productos con Síndrome de Down, (6.25), primer producto reportó durante la valoración de la ecografía del primer trimestre TN > 3mm, Triple test positivo riesgo 1:50, ecografía 3D presentó inserción baja de la oreja, sexo masculino; segundo producto reportó en la ecografía del primer trimestre TN 3.2mm, ductus venoso invertido, triple test positivo, riesgo 1:30. Eco 3D presentó inserción baja de las orejas, atresia duodenal, comunicación interauricular. Conclusiones: combinado ambos tamizajes (primer y segundo trimestre) para el diagnóstico de cromosomopatías, se presenta un mejor perfil de eficacia, seguridad y costo-eficiencia. Mediante ambos métodos no invasivos, inocuos, sin riesgos para el binomio madre – feto y poseen una amplia aplicación clínica.

Study type: prospective, observational, and longitudinal. General objective: to compare echographic findings with those of the triple test as cribation methods for prenatal diagnosis in high risk women. Methodology: pregnant patients randomly chosen≥35 years old seen in the maternal-infantile area of the “Teodoro Maldonado Carbo” IESS hospital from december/2006 to may/2007. At 11th-14th pregnancy weeks (PW) echographic cribation for chromosomal pathologies . At 15-20 weeks biochemical study (triple test) in Medilabsa laboratory. At 18-22 PW the echographic cribation for chromosomal pathologies was made once again to confirm results. Results: out of 31 assessed patients: one spontaneous abortion at PW 16.4 (3.22); two Down’s Syndrome (6.25), the first one in the 1st. quarter echography showed NT > 3mm, positive risk 1:50 triple test; 3D echography showed low insertion of the ear, male. The second one showed in 1st quarter echography NT > 3.2mm, inverted venous ductus, positive,risk 1:30 triple test; 3D echography showed low insertion of the ears, duodenal atresia, atrial septum defect. Conclusions: making a combination of both cribations (1st and 2nd quarters) for diagnosing chromosome pathologies, we have more efficiency, safety and better cost-benefit. Both methods are non invasive, innocuous, risk free for mother as well as for fetus and are extensively applied as a clinical procedure.