Fundamental research on the label-free detection of protein adsorption using near-infrared light-responsive plasmonic metal nanoshell arrays with controlled nanogap

In this work, we focused on the label-free detection of simple protein binding using near-infrared light-responsive plasmonic nanoshell arrays with a controlled interparticle distance. The nanoshell arrays were fabricated by a combination of colloidal self-assembly and subsequent isotropic helium plasma etching under atmospheric pressure. The diameter, interparticle distance, and shape of nanoshells can be tuned with nanometric accuracy by changing the experimental conditions. The Au, Ag, and Cu nanoshell arrays, having a 240-nm diameter (inner, 200-nm polystyrene (PS) core; outer, 20-nm metal shell) and an 80-nm gap distance, exhibited a well-defined localized surface plasmon resonance (LSPR) peak at the near-infrared region. PS@Au nanoshell arrays showed a 55-nm red shift of the maximum LSPR wavelength of 885 nm after being exposed to a solution of bovine serum albumin (BSA) proteins for 18 h. On the other hand, in the case of Cu nanoshell arrays before/after incubation to the BSA solution, we found a 30-nm peak shifting. We could evaluate the difference in LSPR sensing performance by changing the metal materials

Fabrication of ultrathin and highly uniform silicon on insulator by numerically controlled plasma chemical vaporization machining

Metal-oxide semiconductor field-effect transistors fabricated on a silicon-on-insulator (SOI) wafer operate faster and at a lower power than those fabricated on a bulk silicon wafer. Scaling down, which improves their performances, demands thinner SOI wafers. In this article, improvement on the thinning of SOI wafers by numerically controlled plasma chemical vaporization machining (PCVM) is described. PCVM is a gas-phase chemical etching method in which reactive species generated in atmospheric-pressure plasma are used. Some factors affecting uniformity are investigated and methods for improvements are presented. As a result of thinning a commercial 8 in. SOI wafer, the initial SOI layer thickness of 97.5±4.7 nm was successfully thinned and made uniform at 7.5±1.5 nm. © 2007 American Institute of Physics.Yasuhisa Sano, Kazuya Yamamura, Hidekazu Mimura, Kazuto Yamauchi, and Yuzo Mori, "Fabrication of ultrathin and highly uniform silicon on insulator by numerically controlled plasma chemical vaporization machining", Review of Scientific Instruments 78(8), 086102 (2007) https://doi.org/10.1063/1.2766836

Phase separation of a ternary lipid vesicle including n-alkane: Rugged vesicle and bilayer flakes formed by separation between highly rigid and flexible domains

We investigate the phase separation of a ternary lipid bilayer including n-alkane and construct the ternary phase diagram. When a certain proportion of a long n-alkane is mixed with a binary mixture of lipids, which exhibit the disordered liquid-crystalline phase and the ordered gel phase at room temperature, we observed the characteristic morphology of bilayers with phase separation. The ordered bilayer forms flat and rigid domains, which is connected or rimmed with flexible domains in the disordered phase. The asymmetric emergence of the phase separation region close to the ordered phase side is interpreted based on the almost equal distribution of the n-alkane to the ordered and disordered phase domains

Novel method to rescue a lethal phenotype through integration of target gene onto the X-chromosome.

The loss-of-function mutations of serine protease inhibitor, Kazal type 1 (SPINK1) gene are associated with human chronic pancreatitis, but the underlying mechanisms remain unknown. We previously reported that mice lacking Spink3, the murine homologue of human SPINK1, die perinatally due to massive pancreatic acinar cell death, precluding investigation of the effects of SPINK1 deficiency. To circumvent perinatal lethality, we have developed a novel method to integrate human SPINK1 gene on the X chromosome using Cre-loxP technology and thus generated transgenic mice termed "X-SPINK1". Consistent with the fact that one of the two X chromosomes is randomly inactivated, X-SPINK1 mice exhibit mosaic pattern of SPINK1 expression. Crossing of X-SPINK1 mice with Spink3+/- mice rescued perinatal lethality, but the resulting Spink3-/-;XXSPINK1 mice developed spontaneous pancreatitis characterized by chronic inflammation and fibrosis. The results show that mice lacking a gene essential for cell survival can be rescued by expressing this gene on the X chromosome. The Spink3-/-;XXSPINK1 mice, in which this method has been applied to partially restore SPINK1 function, present a novel genetic model of chronic pancreatitis

Electrostatic double-layer interaction between stacked charged bilayers

The inapplicability of the DLVO theory to multilayered anionic bilayers is found in terms of the co-ion-valence dependence of the lamellar repeat distance. Most of the added salt is expelled from the interlamellar space to the bulk due to the Gibbs-Donnan effect on multiple bilayers with the bulk. The electrostatic double-layer interaction is well expressed by the formula recently proposed by Trefalt. The osmotic pressure due to the expelled ions, rather than the van der Waals interaction, is the main origin of the attractive force between the bilayers

Efficient focusing of hard x rays to 25 nm by a total reflection mirror

Nanofocused x rays are indispensable because they can provide high spatial resolution and high sensitivity for x-ray nanoscopy/spectroscopy. A focusing system using total reflection mirrors is one of the most promising methods for producing nanofocused x rays due to its high efficiency and energy-tunable focusing. The authors have developed a fabrication system for hard x-ray mirrors by developing elastic emission machining, microstitching interferometry, and relative angle determinable stitching interferometry. By using an ultraprecisely figured mirror, they realized hard x-ray line focusing with a beam width of 25 nm at 15 keV. The focusing test was performed at the 1-km -long beamline of SPring-8. © 2007 American Institute of Physics.Hidekazu Mimura, Hirokatsu Yumoto, et al. "Efficient focusing of hard x rays to 25nm by a total reflection mirror", Appl. Phys. Lett. 90(5), 051903 (2007) https://doi.org/10.1063/1.2436469

Gastrointestinal Endoscopy for Patients with High Levels of Serum CEA and CA19-9

Serum levels of tumor markers, such as carcinoembryonic antigen （CEA） and carbohydrate antigen 19-9 （CA19-9）, are often measured to detect potential malignancy. When these levels are high, the presence or absence of malignancy is confirmed via a more detailed examination using gastrointestinal （GI） endoscopy and computed tomography. The rate of confirmation of malignancy upon such a follow-up is unknown. This study aimed to investigate the malignancy detection rate via GI endoscopy for patients with high levels of serum CEA and CA19-9. All patients who underwent such GI endoscopy between January 2018 and February 2019 at Showa University Hospital were included in this study. The patients were divided into a follow-up group and a screening group, depending on the purpose of measuring their serum CEA/CA19-9 levels. There were 156 patients who underwent GI endoscopy because of high CEA/CA19-9 levels within the study period. Advanced malignant lesions were detected in 10 patients （6.4％）, including seven cases of colorectal cancer and three cases of upper GI malignancies. In the screening group, six cases （5.7％） of GI malignancies were detected, none of which were found in asymptomatic patients without anemia. In the follow-up group, four cases （7.8％） of GI malignancies were detected; three patients were asymptomatic, and one patient had anemia. Our findings suggest that high serum CEA/CA19-9 levels in asymptomatic patients without anemia and without a history of malignancy do not indicate the presence of malignancy. However, high serum CEA/CA19-9 levels may indicate the potential presence of GI malignancies for patients with a history of malignant tumors, even if they are asymptomatic and do not have anemia

Reassessment of structure of smectic phases: Nano-segregation in smectic E phase in 4-n-alkyl-4′-isothiocyanato-1,1′-biphenyls

Based on new diffraction data from aligned samples of smectic E (SmE) phase of 4-n-alkyl-4′-isothiocyanato-1,1′-biphenyls, systematics against the alkyl chain length n is analyzed. In order to perform the analysis, the molecular form factor approximated by a box-shaped distribution is calculated while taking the rounding of the distribution at corners into account. The analysis clearly shows the nano-segregated layered structure, which does not fit to the traditional structural view of SmE phase but does fit to the model the present authors proposed recently. Some implications of this conclusion are discussed in relation to the importance of the molten state of alkyl chains in most of real mesogens revealed previously through thermodynamic analyses