21 research outputs found

    Photo-degradation Analysis of Luminescent Polymers with Lanthanide Complexes

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    UV durability of luminescent Eu(III) complexes for future solar cell application is estimated using Fourier transform infrared spectroscopy (FT-IR). Sandwich-typed glass cells containing Eu(III) complexes powders under UV irradiation are used for the carbonyl index analysis (calculation of decomposition percentage of organic ligands) using FT-IR measurements. The durability of Eu(hfa)3(TPPO)2 (hfa: hexafluoroacetylacetonate, TPPO: triphenylphospine oxide) is five times larger than that of Eu(tta)3(phen) (tta: trifluoromethylthienylacetylacetonate, phen: phenanthroline). Photophysical performance of Eu(III) complexes under UV irradiation is also evaluated using emission lifetimes and external quantum efficiency measurements of the solar cell module using EVA films with Eu(III) complexes. Photo-degradation analysis of luminescent polymer thin films with Eu(III) complexes are demonstrated for the first time

    Photo- and thermo-stable luminescent beads composed of Eu(III) complexes and PMMA for enhancement of silicon solar cell efficiency

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    Photo-and thermo-stable luminescent beads composed of Eu(hfa)(3)(TPPO)(2) (hfa: hexafluoroacetylacetonate, TPPO: triphenylphosphine oxide) and PMMA (polymethylmethacryrate), Eu(hfa)(3)(TPPO)(2)-beads, have been reported for improvement of energy conversion efficiency on silicon solar cell. The photophysical properties of Eu(hfa)(3)(TPPO)(2) and compared Eu(tta)(3)(TPPO)(2) (tta: trifluoromethyl- thienylacetylacetonate) are characterized by the emission quantum yield, the emission lifetime, the radiative and the non-radiative rate constants. Photo-and thermo-stability of the beads with Eu(III) complexes in EVA (Ethylene Vinyl Acetate) are estimated under UV irradiation (Xenon lamp: 60 W/m(2)) and highly temperature (120 degrees C). The stability of the Eu(hfa)(3)(TPPO)(2)-beads for industrial application was calculated to be ten years under air condition. Energy conversion efficiency of silicon solar cells attached EVA films with Eu(hfa)(3)(TPPO)(2)-beads increased approximately 2%(10% -> 10.2%) compared with EVA films contained with UV absorber. Photo-and thermo-stable Eu(hfa)(3)(TPPO)(2)-beads for silicon solar cells are demonstrated for the first time

    Aging decreases docosahexaenoic acid transport across the blood-brain barrier in C57BL/6J mice.

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    Nutrients are actively taken up by the brain via various transporters at the blood-brain barrier (BBB). A lack of specific nutrients in the aged brain, including decreased levels of docosahexaenoic acid (DHA), is associated with memory and cognitive dysfunction. To compensate for decreased brain DHA, orally supplied DHA must be transported from the circulating blood to the brain across the BBB through transport carriers, including major facilitator superfamily domain-containing protein 2a (MFSD2A) and fatty acid-binding protein 5 (FABP5) that transport esterified and non-esterified DHA, respectively. Although it is known that the integrity of the BBB is altered during aging, the impact of aging on DHA transport across the BBB has not been fully elucidated. We used 2-, 8-, 12-, and 24-month-old male C57BL/6 mice to evaluate brain uptake of [14C]DHA, as the non-esterified form, using an in situ transcardiac brain perfusion technique. Primary culture of rat brain endothelial cells (RBECs) was used to evaluate the effect of siRNA-mediated MFSD2A knockdown on cellular uptake of [14C]DHA. We observed that the 12- and 24-month-old mice exhibited significant reductions in brain uptake of [14C]DHA and decreased MFSD2A protein expression in the brain microvasculature compared with that of the 2-month-old mice; nevertheless, FABP5 protein expression was up-regulated with age. Brain uptake of [14C]DHA was inhibited by excess unlabeled DHA in 2-month-old mice. Transfection of MFSD2A siRNA into RBECs decreased the MFSD2A protein expression levels by 30% and reduced cellular uptake of [14C]DHA by 20%. These results suggest that MFSD2A is involved in non-esterified DHA transport at the BBB. Therefore, the decreased DHA transport across the BBB that occurs with aging could be due to age-related down-regulation of MFSD2A rather than FABP5

    The level of salivary lactate dehydrogenase as an indicator of the association between gingivitis and related factors in Japanese university students

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    The aim of this study was to investigate the association between the presence of gingivitis estimated using the salivary level of lactate dehydrogenase (LD) and related factors in young Japanese adults. Data from 1,915 participants (21.4 ± 2.5 years) were analyzed. Unstimulated saliva was collected from each participant and the salivary LD level was evaluated using a commercially available test kit with an integer scale ranging from 1 to 10. Gingivitis was defined as the LD level of ≥8. The number of permanent teeth, the simplified oral hygiene index (OHI-S), the presence of partially erupted molars and body mass index were recorded. Additionally, participants answered a questionnaire. The percentage of male participants, the number of permanent teeth, the OHI-S and the presence of partially erupted molars were higher, whereas the proportion receiving dental check-ups was lower in the gingivitis group (n = 88, 4.6%) than in the healthy group. Logistic regression analysis showed that gingivitis was significantly associated with OHI-S (OR: 2.68, 95% CI: 1.94-3.69) and receiving dental checkups (OR: 0.31, 95% CI: 0.10-0.99). The present findings indicated that the OHI-S and receiving dental checkups were significantly associated with gingivitis, as assessed by the salivary LD level, in this cohort

    Validity of a New Kit Measuring Salivary Lactate Dehydrogenase Level for Screening Gingivitis

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    Aim. The aim of this study was to determine the usefulness of a new kit that can evaluate salivary lactate dehydrogenase (LD) level in real time for screening gingivitis. Materials and Methods. The study included 70 systemic healthy volunteers [29 males and 41 females; mean age ± SD: 24.1±2.6 years]. Resting saliva was collected from each participant and LD level was evaluated in real time using the kit (a color-changing sheet with an integer scale ranging from 1 to 10). A dentist measured probing pocket depth, clinical attachment level, and the proportion of sites with bleeding on probing (% BOP) at six sites on all teeth. Gingivitis was diagnosed when the BOP value was ≥20%. Results. Salivary LD level was positively correlated with mean % BOP (odds ratio: 1.47, 95% confidence interval: 1.132–1.916, and P<0.001) in a logistic regression model. The sensitivity and specificity of the kit were 0.89 and 0.98, respectively, at a cut-off value of 8.0 for LD level. Conclusions. The new kit for measurement of salivary LD level may be a useful tool to screen for gingivitis in young adults, which contributes to early detection of future periodontitis

    Association between Knowledge about Comprehensive Food Education and Increase in Dental Caries in Japanese University Students: A Prospective Cohort Study

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    In Japan, comprehensive food education (shokuiku) programs are carried out with the aim of improving dietary practices and thereby reducing the incidence of lifestyle-related diseases, including dental caries. The purpose of this prospective cohort study was to investigate the association between knowledge about shokuiku and the increase in dental caries among Japanese university students who had attended a shokuiku program while in junior/senior high school. A total of 562 students volunteered to undergo oral examinations over a three-year follow-up period, during which the number of cases of dental caries were recorded. Additional information was collected using a questionnaire survey regarding knowledge about shokuiku, dietary habits, and oral health behaviors. In logistic regression analysis, males who lacked knowledge about shokuiku had significantly higher odds for dental caries than those who did not (odds ratio (OR), 2.00; 95% confidence interval (CI), 1.12–3.58; p = 0.019). On the other hand, among females, those who frequently consumed sugar-sweetened soft drinks had significantly higher odds for dental caries than those who did not (OR, 1.89; 95% CI, 1.05–3.42; p = 0.035). These results suggest that having no knowledge about shokuiku is associated with a risk of increase in dental caries in Japanese male university students

    MicroRNAs Induce Epigenetic Reprogramming and Suppress Malignant Phenotypes of Human Colon Cancer Cells.

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    Although cancer is a genetic disease, epigenetic alterations are involved in its initiation and progression. Previous studies have shown that reprogramming of colon cancer cells using Oct3/4, Sox2, Klf4, and cMyc reduces cancer malignancy. Therefore, cancer reprogramming may be a useful treatment for chemo- or radiotherapy-resistant cancer cells. It was also reported that the introduction of endogenous small-sized, non-coding ribonucleotides such as microRNA (miR) 302s and miR-369-3p or -5p resulted in the induction of cellular reprogramming. miRs are smaller than the genes of transcription factors, making them possibly suitable for use in clinical strategies. Therefore, we reprogrammed colon cancer cells using miR-302s and miR-369-3p or -5p. This resulted in inhibition of cell proliferation and invasion and the stimulation of the mesenchymal-to-epithelial transition phenotype in colon cancer cells. Importantly, the introduction of the ribonucleotides resulted in epigenetic reprogramming of DNA demethylation and histone modification events. Furthermore, in vivo administration of the ribonucleotides in mice elicited the induction of cancer cell apoptosis, which involves the mitochondrial Bcl2 protein family. The present study shows that the introduction of miR-302s and miR-369s could induce cellular reprogramming and modulate malignant phenotypes of human colorectal cancer, suggesting that the appropriate delivery of functional small-sized ribonucleotides may open a new avenue for therapy against human malignant tumors
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