Search

Composites are being researched as lightweight, thermal‐insulating alternatives to glass; however, composite materials are generally opaque. In this study, a transparent composite is developed based on E‐glass fiber and a polymer blend by matching their refractive indices. To avoid the opacity caused by phase separation, a polymer blend featuring highly miscible polycarbonate (PC) and polycaprolactone (PCL) is used as the matrix of the composite. The refractive indices of PC and PCL are higher and lower, respectively, than that of E‐glass fiber; thus, the refractive index of a PC–PCL blend can be matched with that of E‐glass fiber by optimizing its composition (PC:PCL weight ratio). Moreover, the crystallization of PCL in a PC–PCL blend is inhibited by the incorporation of sufficient PC, eliminating the light scattering associated with crystalline PCL. The transparency of the proposed composite based on E‐glass fiber and a PC–PCL blend is optimal at a PC:PCL weight ratio of 65:35. Furthermore, the impregnation of a glass‐fiber textile with a PC–PCL blend with a PC:PCL weight ratio of 65:35 under evacuated conditions produces a strong, transparent composite with tensile and impact strengths that exceed those of PC and a corresponding short glass fiber–reinforced composite. [ABSTRACT FROM AUTHOR]

Polypropylene (PP)/clay nanocomposites (PPCNs) were autoclave-foamed in a batch process. Foaming was performed using supercritical 002 at 10 MPa, within the temperature range from 130.6[degrees] to 143.4[degrees]. i.e., below the melting temperature of either PPCNs or maleic anhydride-modified PP (PP-MA) matrix without clay. The foamed PP-MA and PPCN2 (prepared at 130.6[degrees]C and containing 2 wt% clay) show closed cell structures with pentagonal and/or hexagonal faces, while foams of PPCN4 and PPCN7.5 (prepared at 143.400, 4 and 7.5 wt% clay) had spherical cells. Scanning electron microscopy confirmed that foamed PPCNs had high cell density of [10.sup.7]-[10.sup.8] cells/mL, cell sizes in the range of 30-120 [mu]m, cell wall thicknesses of 5-15 [mu]m, and low densities of 0.05-0.3 g/mL. Interestingly, transmission electron microscopic observations of the PPCNs' cell structure showed biaxial flow-induced alignment of clay particles along the cell boundary. In this paper, the correlation between foam structure and reheological properties of the PPCNs is also discussed.

• The article represents an extremely rare case of the combination of choledochocele and extra-hepatic bile duct duplication. • The combination of choledochocele and bile duct duplication might escalate the pancreatitis and cholangitis progression. • The pathogenesis in relation to pancreaticobiliary maljunction is discussed. Combination of choledochocele and extra-hepatic duct duplication is an extremely rare congenital abnormality. The patient was an 81-year-old Japanese man. He visited the emergency room for severe abdominal colic pain. He was diagnosed with severe pancreatitis with cholelithiasis and treated conservatively by percutaneous trans-hepatic gallbladder drainage (PTGBD) for 4 months. Thereafter, he was transferred to our institute and cholangiography was performed via the PTGBD tube, revealing cholecysto- and choledocho-lithiasis. The cystic-duct joined the right hepatic duct with extra-hepatic bile duct duplication and the terminal bile duct flowed into the cystic papilla of Vater. The main pancreatic duct also joined into the cystic papilla. These observations confirmed choledochocele with extra-hepatic bile duct duplication. Surgical exploration was performed, and hepatico-jejunostomy with hepatic-ductplasty and cholecystectomy with choledocholithotomy were carried out. He was discharged and his course was uneventful. A very rare combined case of choledochocele with bile duct duplication, which would escalate the pancreatitis and cholangitis, was successfully treated. Their pathogeneses in relation to pancreaticobiliary maljunction is discussed. [ABSTRACT FROM AUTHOR]

The synthesis of oxygen-free, phenyl-modified organosilicon nanosheets with atomic thickness is described. Light-induced photocurrent in [[Si.sub.6][H.sub.4][Ph.sub.2]] is observed, which has led to the possibility of various organosilicon nanomaterials with useful properties.

Oxygen-free silicon nanosheets covered with organic groups are obtained by exfoliation of layered polysilane as a result of reaction with n-decylamine and dissolution in an organic solvent. The nanosheets have very flat and smooth surfaces because of dense coverage of n-decylamine and they are self-assembled in a concentrated state to form a regularly stacked structure.

The cover image by Takayuki Hirai, Yoshimi Muraoka, and Hirotaka Okamoto shows transparent composites achieved by refractive index matching between glass fiber textiles and polymer blends of polycarbonate (PC) and polycaprolactone (PCL). The PC/PCL blend shows good transparency due to its miscibility, and refractive index matching between glass fiber and PC/PCL blend can be achieved by optimizing a composition ratio of PC and PCL. The transparent composite was obtained by impregnating the refractive index adjusted PC/PCL into a woven glass fiber. [Extracted from the article]

Boron nitride nanosheets (BNNSs) with micron-sized edges were prepared in high yields by direct exfoliation of bulk hexagonal boron nitrides using ionic liquids (ILs). The ILs strongly attached onto BNNS surfaces, and dramatically enhanced the exfoliation, giving highly concentrated BNNS dispersions (∼1.9 mg mL−1) and yields reaching ∼50%. [ABSTRACT FROM AUTHOR]

ABSTRACT Shape-recovery materials are expected to have numerous applications as ductile structural compounds which can recover their shape after significant deformations. We report a new type of shape-recovery polymer consisting of polylactic acid (PLA) derived from glucose compounded with a cinnamic acid ester derived from lignin. Unlike existing shape-memory polymers, this shape-recovery polymer exhibits a spontaneous but gradual recovery of its original dimensions, following elongation and release of stress, over a period ranging from several hours to days, without the requirement for external stimulus. In the case of a typical rubber or elastomer, shape-recovery takes place almost instantaneously after deformation due to the energy stored by the material. Although the slow shape-recovery polymer reported herein appears to exhibit plastic deformation as if the energy of elongation is lost, it eventually recovers from the deformation in the same manner as an elastic material. This material may have applicability to the energy-absorbing and shape restoration automotive parts. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41004. [ABSTRACT FROM AUTHOR]

Polycarbonates were synthesized by transesterification polymerization of isosorbide, bisphenol A, and diphenyl carbonate in the presence of n-BuSn(O)OH as the catalyst. The polymers were prepared by varying the ratio of the two monomers. The polymers exhibited good thermal stability, rigidity, and strength. The storage moduli for the polymers were 2.6 to 3.2 GPa at 25°C and increased with increasing isosorbide content. The dynamic mechanical analysis indicated that the storage moduli ( E′) of the polymers are constant to higher temperatures than that of bisphenol A polycarbonate. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2012 [ABSTRACT FROM AUTHOR]

Acrylonitrile-Butadiene-Styrene Copolymer (ABS)/Clay Nanocomposites have been prepared by the melt intercalation method with a twin screw extruder. In the nanocomposite, the silicate layers of montmorillonite were not exfoliated to monolayers, but were dispersed to 5 to 10 stacked layers. These stacked silicate layers of montmorillonite were around butadiene rubber domains of the high impact polystyrene in ABS. This unique dispersion state is the result from the intercalation of polystyrene into silicate layers. When 5 wt% clay was added, tensile modulus was 1.2 times greater than that of ABS. [ABSTRACT FROM AUTHOR]

Reports on the autoclave-foam processing and cellular structure of polypropylene/clay nanocomposites. Maleic anhydride-modified polypropylene matrix without clay; Biaxial flow-induced alignment of clay particles; Uniaxial elongation flow.

Although endothelial cell retraction is required before tumor cell invasion, its molecular mechanism still remains obscure. We previously demonstrated that conditioned medium (CM) derived from a human pan-creatic cancer cell line, PSN-1, induced endothelial cell retraction and facilitated tumor cell invasion. To investigate the molecular change of events in the transduction of extracellular signals during endothelial cell retraction, we examined the effect of the CM derived from PSN-1 cells on the tyrosine phosphorylation in endothelial cells. Immunoblot analyses revealed that the PSN-1 CM decreased tyrosine phosphorylation of a 120-130 kD protein, and induced the concomitant down-regulation of focal adhesion kinase, pp125FAK , dur-ing endothelial cell retraction in time- and dose-dependent fashions. These changes preceded endothelial cell retraction and were reversible after removal of the CM. Further quantitative densitometric analyses demon-strated that the extent of decrea se in tyrosine phosphorylated 120-130 kD protein during the endothelial cell retraction was likely to be proportional to that of the down-regulation of pp125FAK . A tyrosine phosphory-lated 120-130 kD protein immunoprecipitated by anti-phosphotyrosine antibody immunoreacted with anti-pp125FAK antibody. These results suggested that decreased amount of a tyrosine phosphorylated 120-130 kD protein probably due to the down-regulation of pp125FAK might be associated with the signal transduction pathway in the endothelial cells during their retraction. Furthermore, these findings were also observed in the CM from another four human cancer cell lines, suggesting the down-regulation of pp125FAK in endothelial cells during tumor cell invasion. © Rapid Science 1998 [ABSTRACT FROM AUTHOR]

We have characterized the electron transport properties of n-decylamine-functionalized Si nanosheets (NSs) using atomic force microscopy with a conductive cantilever under vacuum conditions at room temperature. Electrons are transported from the cantilever to the substrate through Si NSs. The Si NSs exhibit nonresonant tunneling; the transport mechanisms are based on direct tunneling at low bias voltages and Fowler-Nordheim tunneling at high bias voltages. [ABSTRACT FROM AUTHOR]

An abstract of the article "Synthesis of Siloxene Derivatives with Organic Groups," by Yusuke Sugiyama, Hirotaka Okamoto, and Hideyuki Nakano is presented.