Decreased expression of DNA repair proteins Ku70 and Mre11 is associated with aging and may contribute to the cellular senescence

The gradual loss of telomeric DNA can contribute to replicative senescence and thus, having longer telomeric DNA is generally considered to provide a longer lifespan. Maintenance and stabilization of telomeric DNA is assisted by binding of multiple DNA-binding proteins, including those involved in double strand break (DSB) repair. We reasoned that declining DSB repair capacity and increased telomere shortening in aged individuals may be associated with decreased expression of DSB repair proteins capable of telomere binding. Our data presented here show that among the DSB repair proteins tested, only the expression of Ku70 and Mre11 showed statistically significant age-dependent changes in human lymphocytes. Furthermore, we found that expressions of Ku70 and Mre11 are statistically correlated, which indicate that the function of Ku70 and Mre11 may be related. All the other DSB repair proteins tested, Sir2, TRF1 and Ku80, did not show any significant differences upon aging. In line with these data, people who live in the regional community (longevity group), which was found to have statistically longer average life span than the rest area, shows higher level of Ku70 expression than those living in the neighboring control community. Taken together, our data show, for the first time, that Ku70 and Mre11 may represent new biomarkers for aging and further suggest that maintenance of higher expression of Ku70 and Mre11 may be responsible for keeping longer life span observed in the longevity group.     

A facile one-pot synthesis of novel amphiphilic perfluoroalkyl ester functionalized γ-cyclodextrin and complex formation with anionic surfactants

γ-Cyclodextrin (γ-CyD) was hydrophobically modified by selective functionalization at the C-6 position (primary face) with fluoroalkyl ester groups. This new amphiphilic γ-CyD was prepared in a facile one-pot synthesis by direct esterification of γ-CyD with perfluorobutanoic acid on the narrow rim of macrocylic molecule. The selective per-substituted product, octakis (6-O-perfluorobutanoyl)-γ-cyclodextrin (γ-CyD-F), was confirmed by ¹H NMR, ¹³C NMR and ¹⁹F NMR spectroscopic methods. The complexing ability of the γ-CyD-F was investigated with different types of anionic surfactant having single or double hydrophobic tail groups. Predominant complex formation was observed in all cases with an equimolar mixture of surfactant and γ-CyD-F in methanol irrespective of the type of the surfactant.     

Phosphor in glasses with Pb-free silicate glass powders as robust color-converting materials for white LED applications

Phosphor-in-glass (PiG) typed robust color converters were fabricated using Pb-free silicate glasses for high-power white LED applications. SiO₂-B₂O₃-RO(R=Ba,Zn) glass powder showed good sintering behavior and high visible transparency under the sintering condition of 750?°C for 30?min without noticeable interaction with phosphors. By simply changing the thickness of the PiG plate or mixing ratio of glass to Y₃Al₅O₁₂:Ce³⁺ phosphor, CIE chromaticity coordinates of the LED can be easily controlled. Enhanced thermal quenching property of PiG compared to phosphor with conventional silicone resin suggests its prominent feasibility for high-power/high-brightness white LEDs.     

Effects of electron irradiation on the properties of GZO films deposited with RF magnetron sputtering

Transparent conductive GZO films were deposited on polycarbonate substrates by electron beam assisted radio frequency (RF) magnetron sputtering and then the influence of electron irradiation on the structural, optical and electrical properties of GZO films was investigated by using X-ray diffractometry, UV-vis spectrophotometry, four point probes, atomic force microscopy and UV photoelectron spectroscopy. Sputtering power was kept constant at 3 W/cm² during deposition, while electron irradiation energy varied from 450 to 900 eV.Electron irradiated GZO films show larger grain sizes than those of films prepared without electron irradiation, and films irradiated at 900 eV show higher optical transmittance in the visible wavelength region and lower sheet resistance (120 Ω/□) than other films. The work-function is also increased with electron irradiation energy. The highest work-function of 4.4 eV was observed in films that were electron irradiated at 900 eV.     

Representations of invariant multilinear maps on HilbertC*-modules

The definition of a completely positive invariant multilinear map from aC*-algebra to another is introduced. We construct the representation of a completely positive invariant multilinear map on a HilbertC*-module without the bridging maps. This is another extension of the Stinespring’s representation, which is different from a multilinear representation of Christensen and Sinclair. We give the covariant representation of completely positive invariant covariant multilinear maps on a HilbertC*-module. Further, we investigate the order structure of such maps and obtain a generalization of the Radon-Nikodym theorem. Partially supported by GARC-KOSEF.     

Effects of Bisphenol A and Its Alternatives,Bisphenol F and Tetramethyl Bisphenol F on Osteoclast Differentiation

Bisphenol A (BPA) is a typical environmental endocrine disruptor that exhibits estrogen-mimicking, hormone-like properties and can cause the collapse of bone homeostasis by an imbalance between osteoblasts and osteoclasts. Various BPA substitutes, structurally similar to BPA, have been used to manufacture ‘BPA-free’ products; however, the regulatory role of BPA alternatives in osteoclast differentiation still remains unelucidated. This study aimed to investigate the effects of these chemicals on osteoclast differentiation using the mouse osteoclast precursor cell line RAW 264.7. Results confirmed that both BPA and its alternatives, bisphenol F and tetramethyl bisphenol F (TMBPF), were nontoxic to RAW 264.7 cells. In particular, tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cell staining and activity calculation assays revealed that TMBPF enhanced osteoclast differentiation upon stimulation of the receptor activator of nuclear factor-kappa B ligand (RANKL). Additionally, TMBPF activated the mRNA expression of osteoclast-related target genes, such as the nuclear factor of activated T-cells, cytoplasmic 1 (NFATc1), tartrate-resistant acid phosphatase (TRAP), and cathepsin K (CtsK). Western blotting analysis indicated activation of the mitogen-activated protein kinase signaling pathway, including phosphorylation of c-Jun N-terminal kinase and p38. Together, the results suggest that TMBPF enhances osteoclast differentiation, and it is critical for bone homeostasis and skeletal health.     

A Penalized Matrix Normal Mixture Model for Clustering Matrix Data

Along with advances in technology, matrix data, such as medical/industrial images, have emerged in many practical fields. These data usually have high dimensions and are not easy to cluster due to their intrinsic correlated structure among rows and columns. Most approaches convert matrix data to multi dimensional vectors and apply conventional clustering methods to them, and thus, suffer from an extreme high-dimensionality problem as well as a lack of interpretability of the correlated structure among row/column variables. Recently, a regularized model was proposed for clustering matrix-valued data by imposing a sparsity structure for the mean signal of each cluster. We extend their approach by regularizing further on the covariance to cope better with the curse of dimensionality for large size images. A penalized matrix normal mixture model with lasso-type penalty terms in both mean and covariance matrices is proposed, and then an expectation maximization algorithm is developed to estimate the parameters. The proposed method has the competence of both parsimonious modeling and reflecting the proper conditional correlation structure. The estimators are consistent, and their limiting distributions are derived. We applied the proposed method to simulated data as well as real datasets and measured its clustering performance with the clustering accuracy (ACC) and the adjusted rand index (ARI). The experiment results show that the proposed method performed better with higher ACC and ARI than those of conventional methods.     

Estimates for the p-Laplacian-type operator in the subcritical Sobolev exponent range

We obtain Calderón–Zygmund-type gradient estimates below the duality exponent of very weak solutions to p-Laplacian-type elliptic equations with non-divergence datum by providing an analytic approach without using the fractional maximal function of order 1 for the non-divergence datum.