Stretchable Strain Sensor with Small but Sufficient Adhesion to Skin.

Stretchable strain sensors that use a liquid metal (eutectic gallium-indium alloy; E-GaIn) and flexible silicone rubber (Ecoflex) as the support and adhesive layers, respectively, are demonstrated. The flexibility of Ecoflex and the deformability of E-GaIn enable the sensors to be stretched by 100%. Ecoflex gel has sufficiently large adhesion force to skin, even though the adhesion force is smaller than that for commercially available adhesives. This enables the sensor to be used for non-invasive monitoring of human motion. The mechanical and electrical properties of the sensor are experimentally evaluated. The effectiveness of the proposed sensors is demonstrated by monitoring joint movements, facial expressions, and respiration.

Localization and expression of the Bacillus subtilis DL-endopeptidase LytF are influenced by mutations in LTA synthases and glycolipid anchor synthetic enzymes.

Bacillus subtilis LytF plays a principal role in cell separation through its localization at the septa and poles on the vegetative cell surface. In this study, we found that a mutation in a major lipoteichoic acid (LTA) synthase gene--ltaS--results in a considerable reduction in the σ(D)-dependent transcription of lytF. The lytF transcription was also reduced in mutants that affected glycolipid anchor biosynthesis. Immunofluorescence microscopy revealed that both the numbers of cells expressing LytF and the LytF foci in these mutants were decreased. In addition, the transcriptional activity of lytF was almost abolished in the double (ltaS yfnI), triple (ltaS yfnI yqgS), and quadruple (ltaS yfnI yqgS yvgJ) mutants during vegetative growth. Cell separation defects in these mutants were partially restored with artificial expression of LytF. Interestingly, when lytF transcription was induced in the ltaS single or multiple mutants, LytF was localized not only at the septum, but also along the sidewall. The amounts of LytF bound to cell wall in the single (ltaS) and double (ltaS yfnI) mutants gradually increased as compared with that in the WT strain, and those in the triple (ltaS yfnI yqgS) and quadruple mutants were almost similar to that in the double mutant. Moreover, reduction of the lytF transcription and chained cell morphology in the ltaS mutant were completely restored with artificial induction of the yqgS gene. These results strongly suggest that LTA influences the temporal, σ(D)-dependent transcription of lytF and is an additional inhibitory component to the vegetative cell separation enzyme LytF.

Evaluation of Inactivation of Murine Norovirus in Inoculated Shell Oysters by High Hydrostatic Pressure Treatment.

One of the major foods causing norovirus gastroenteritis is bivalve shellfish, such as oysters. Depuration and relaying methods have been used to control norovirus. However, these methods may be inadequate to control norovirus gastroenteritis. The present study aimed to investigate the effectiveness of high hydrostatic pressure (HHP) treatment in controlling norovirus in shelled oysters, by evaluating the inactivating effect of HHP on murine norovirus strain 1 (MNV-1) inoculated into a buffer, oyster homogenate, and shelled oysters. First, MNV-1 was inoculated (infectivity of 4.5 log PFU/mL) into the buffer and oyster homogenate, with a pH of 6.3 and salinity (NaCl) of 1.5%, mimicking the habitats of the Pacific oyster (Crassostrea gigas). HHP treatment at 100, 200, 275, and 300 MPa for 2 and 5 min was conducted at an initial temperature of 0 or 5°C. The infectivity of MNV-1 in both the buffer and the oyster homogenate was lower when the initial temperature was 0°C. In the buffer, the infectivity of MNV-1 decreased to 1.8 log PFU/mL after HHP treatment (200 MPa for 5 min at 0°C), and the inactivating effect was higher in the buffer than in the oyster homogenate. MNV-1 was inoculated into shelled oysters (4.8 log PFU per oyster), and HHP treatment was done at 275, 300, and 350 MPa for 5 min at the initial temperature of 0°C. The infectivity of MNV-1 decreased to 2.8 log PFU per oyster after HHP treatment at 275 MPa for 5 min. The results indicate that the inactivating effect of HHP treatment varies, depending on the medium surrounding the viral particles. Inactivation was best in buffer, followed by oyster homogenate and shelled oysters. The data could inform the development of methods to control norovirus in oysters.