Centromere protein b-null mice display decreasing reproductive performance through successive generations of breeding due to diminishing endometrial glands

Centromere protein B is a highly conserved constitutive protein found at centromeres. Gene knockout studies in mice have unexpectedly identified Cenpb as a candidate gene involved in uterine function. The present study further explores the role of Cenpb in mice by intermating Cenpb-null mice over several generations. Breeding studies and analysis of uterine tissue indicate that Cenpb-null mice lose reproductive fitness over a number of generations due to a significant reduction in endometrial glands. These results suggest that Cenpb may play an important function in the short- and long-term maintenance of uterine integrity.     

Studies on various chip-on-film (COF) packages using ultra fine pitch two-metal layer flexible printed circuits (two-metal layer FPCs)

Various fine pitch chip-on-film (COF) packages assembled by (1) anisotropic conductive film (ACF), (2) nonconductive film (NCF), and (3) AuSn metallurgical bonding methods using fine pitch flexible printed circuits (FPCs) with two-metal layers were investigated in terms of electrical characteristics, flip chip joint properties, peel adhesion strength, heat dissipation capability, and reliability. Two-metal layer FPCs and display driver IC (DDI) chips with 35 μm, 25 μm, and 20 μm pitch were prepared. All the COF packages using two-metal layer FPCs assembled by three bonding methods showed stable flip chip joint shapes, stable bump contact resistances below 5 mΩ, good adhesion strength of more than 600 gf/cm, and enhanced heat dissipation capability compared to a conventional COF package using one-metal layer FPCs. A high temperature/humidity test (85 °C/85% RH, 1000 h) and thermal cycling test (T/C test, ?40 °C to + 125 °C, 1000 cycles) were conducted to verify the reliability of the various COF packages using two-metal layer FPCs. All the COF packages showed excellent high temperature/humidity and T/C reliability, however, electrically shorted joints were observed during reliability tests only at the ACF joints with 20 μm pitch. Therefore, for less than 20 μm pitch COF packages, NCF adhesive bonding and AuSn metallurgical bonding methods are recommended, while all the ACF and NCF adhesives bonding and AuSn metallurgical bonding methods can be applied for over 25 μm pitch COF applications. Furthermore, we were also able to demonstrate double-side COF using two-metal layer FPCs.     

Poly(ethylene terephthalate)/clay nanocomposites based on aminododecanoic acid-modified clay: effect of compatibilizer reactivity on clay dispersion

Poly(ethylene terephthalate) (PET)/Clay hybrids were prepared via in situ polymerization, in which the clay was modified with 12-aminododecanoic acid (ADA). Three types of bifunctional compounds were introduced into the system, respectively, as compatibilizers between PET and ADA-Clay. The three compounds contain 1 degree, 2 degree, and 3 degree amino groups, respectively, that could form ionic complex with carboxylic acid of ADA. They also contain an ester group that could react with PET chains through transesterification. The results show that adding the compound with 3 degree amino group can improve clay dispersion significantly, while the ones with 1 degree and 2 degree amino groups are not effective compatibilizers. The possible underlying mechanism is discussed.     

Quantitative analysis of methyl parathion pesticides in a polydimethylsiloxane microfluidic channel using confocal surface-enhanced Raman spectroscopy

A fast and ultra-sensitive trace analysis of methyl parathion pesticides in a polydimethylsiloxane (PDMS) microfluidic channel was investigated using confocal surface-enhanced Raman spectroscopy (SERS). A three-dimensional PDMS-based passive micromixer was fabricated for this purpose. This PDMS micromixer showed a high mixing efficiency because a strong chaotic advection was developed by the simultaneous vertical and transverse dispersion of the confluent streams. The confocal SERS signal was measured after methyl parathion pesticides were effectively adsorbed onto silver nanoparticles while flowing along the upper and lower alligator-teeth-shaped PDMS channel. A quantitative analysis of the methyl parathion pesticides was performed based on the measured peak height at 1246 cm-1. Our method has a detection limit of 0.1 ppm. This value satisfies the requirement recommended by the Collaborative International Pesticides Analytical Council (CIPAC) for the determination of methyl parathion in pesticide formulations. This study demonstrates the feasibility of using confocal SERS for the highly sensitive detection of methyl parathion pesticides in a PDMS microfluidic channel.     

Sliding mode robust control of supersonic three degrees-of-freedom airfoils

The robust aeroelastic control of a three-degrees-of-freedom (3DOF) linear and non-linear wing-flap system under sliding mode control (SMC) and operation in supersonic flight speeds is presented. Open- and closed-loop aeroelastic responses to blast and sonic-boom excitation in the wing-flap system with uncertainty, as well as flutter analysis, are investigated along with the implementation of a Sliding Mode Observer (SMO). The effectiveness of control in reducing the amplitude of oscillation and preventing flutter instability is demonstrated.     

Conformational characteristics of poly(ethylene oxide) (PEO) in methanol

The conformational characteristics of poly(ethylene oxide) (PEO) in methanol at 25 °C were investigated by static light scattering and viscometry for high molar mass (M_w) PEO fractions covering M_w = 3.42 × 10⁵-5.05 × 10⁶ g mol⁻¹. No trace of downturn in the plot of angular dependence of Kc/R_θ at low angle was found. Experimental scaling laws for the second virial coefficient (A₂), the third virial coefficient (A₃), the radius of gyration and the intrinsic viscosity ([η]) were determined. The exponents characterizing these scaling laws confirmed that the PEO chain in methanol has a flexible conformation with relatively large excluded volume, but methanol is not as good solvent as water. On the other hand, the low value of interpenetration function (Ψ) and the relatively higher order of the dimensionless parameter Π are considered to be an indication of local chain stiffness. All the results obtained in this study allow us to conclude that the overall chain conformation of PEO assumed in methanol is basically a random coil, but is intermittently mixed with helical structure.     

Transition Metals Supported on Activated Carbon as Benzene Hydroxylation Catalysts

The direct conversion of benzene to phenol by hydroxylation with hydrogen peroxide was carried out over catalyst containing various transition metals impregnated on activated carbon. Iron and vanadium impregnated catalysts gave better yields of phenol compared to copper impregnated catalysts. The activity of transition metals supported on activated carbon catalyst in the production of phenol was V > Fe > Cu. In addition to the role of transition metals in catalyzing the hydroxylation reaction, the hydrophobic nature of the activated carbon surface and also the surface acidity and basicity seems to have enhanced the performance of these catalysts.