Segregation behaviors and radial distribution of dopant atoms in silicon nanowires

Gaining an understanding the dynamic behaviors of dopant atoms in silicon nanowires (SiNWs) is the key to achieving low-power and high-speed transistor devices using SiNWs. The segregation behavior of boron (B) and phosphorus (P) atoms in B- and P-doped SiNWs during thermal oxidation was closely observed using B local vibrational peaks and Fano broadening in optical phonon peaks of B-doped SiNWs by micro-Raman scattering. Electron spin resonance (ESR) signals from conduction electrons were used for P-doped SiNWs. Our results showed that B atoms preferentially segregate in the surface oxide layer, whereas P atoms tend to accumulate in the Si region around the interface of SiNWs. The radial distribution of P atoms in SiNWs was also investigated to prove the difference segregation behaviors between of P and B atoms.     

A novel polysaccharide involved in the pellicle formation of Acetobacter aceti

Acetobacter aceti IFO 3284 has been shown to have two types of strains: one forms a smooth-surfaced colony (S strain) and the other forms a rough-surfaced colony (R strain) (Matsushita et al., 1992). In this study, both S and R strains were isolated and characterized. The S strain grew well in submerged culture but very poorly in static culture. In contrast, the R strain grew well in static culture by floating on the surface of the culture medium, as well as in shaking submerged culture. Scanning electron microscopy revealed that the R strain was covered by some amorphous materials that were not seen in the S strain. The R strain produced 5-fold higher levels of sugars related to polysaccharides responsible for pellicle formation than the S strain did. Unlike cellulose of Acetobacter xylinum, the polysaccharides of the R strain were cellulase-resistant and alkaline-sensitive. The polysaccharides were not secreted into the culture medium, and more than 90% of them were retained in the membrane fraction when the cells were disrupted under mild conditions by lysozyme treatment. Furthermore, the polysaccharides were shown to be mainly attached to the outer membrane when separated. After solubilization with beta-octylglucoside, the membrane-attached polysaccharides were purified by several steps including enzyme treatment, column chromatography and alcohol precipitation. The purified polysaccharide was estimated to have an apparent molecular mass of 700-kDa based on Sephacryl S-500 column chromatography, and to be composed of two monosaccharides, glucose and rhamnose, at an approximately equimolar ratio. Thus, in this study, we clarified that the A. aceti R strain produced a polysaccharide associated with the flotation of the cells on the medium surface, like A. xylinum, and that the polysaccharide was a novel one consisting of glucose and rhamnose.     

Structural classification and similarity measurement of malware

This paper proposes a new lightweight method that utilizes the growing hierarchical self‐organizing map (GHSOM) for malware detection and structural classification. It also shows a new method for measuring the structural similarity between classes. A dynamic link library (DLL) file is an executable file used in the Windows operating system that allows applications to share codes and other resources to perform particular tasks. In this paper, we classify different malware by the data mining of the DLL files used by the malware. Since the malware families are evolving quickly, they present many new problems, such as how to link them to other existing malware families. The experiment shows that our GHSOM‐based structural classification can solve these issues and generate a malware classification tree according to the similarity of malware families. © 2014 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Noninvasive sensing of thermal treatments of Japanese seafood products using imaging spectroscopy

The potential of imaging spectroscopy for noncontact sensing of thermal treatments experienced on Japanese kamaboko was investigated. Samples were thermally treated at 100, 120, 140, 160, 180 and 200 °C to core temperatures of 45, 50, 55, 60, 65, 70, 75 and 80 °C and then promptly cooled and imaged in the short‐wave near infrared spectral range of 900–2500 nm. Partial least square (PLS) regression models were developed using the whole spectral range as well as using the most important wavelengths to predict the core temperature (T_C) and thermal history (TH) yielding a reasonable level of accuracy of ( = 0.86 and RMSEP = 3.9 °C) and ( = 0.83 and RMSEP = 0.29 min), respectively. Moreover, a stepwise linear discriminant analysis (LDA) model was developed for identifying samples whose core temperatures reached a threshold of 65 °C. The LDA model yielded overall classification accuracy of 93.75% in both calibration and validation sets. The resulting discrimination function was then applied in a pixel‐wise manner to produce understandable classification maps to exhibit the difference among samples with high accuracy.     

Comparison between old and new methods for detection of allergenic substances (egg and milk)

The old ELISA method for detection of allergenic substances (egg and milk) in Kanagawa prefecture from 2003 to 2007, employed before improvement of the food allergen labeling system, yielded detection rates of 20% for egg and 30% for milk. In 2005, after improvement of the labeling system, the detection rate using the new ELISA in solutions containing 1% SDS and 7% 2-mercaptoethanol increased by about 10% for egg, but decreased by half for milk. There were 4 positive samples (over 10 μg/g) for both egg and milk proteins, on account of contamination by ingredients at the manufacturing line and the lack of proper food labeling. In 2009, the contamination levels of egg and milk proteins in labeled commercial foods were low. In a comparison between the new and old methods with the same samples, both the new ELISA and Western-blot analyses showed an increase in the detection rate of egg protein. In relation to milk protein, the detection rates were decreased with the new ELISA, although the ELISA detection rate and consistency rates with Western-blot analysis were increased. On the other hand, in the case of a protein content below 5 μg/g, it was impossible to determine ovomucoid and casein by Western-blot analysis.     

Purification and characterisation of two extracellular acid proteinases from Monascus pilosus

Genus Monascus is one of the most important microorganisms in the fermentation industry in Asia. However, only a little attention has been paid to the proteinases produced by this fungus and their role in the fermentation process. The main objective of this study was to purify and characterise acid proteinases produced by Monascus pilosus. Two acid proteinases (MpiAP1 and MpiAP2) were purified to homogeneity. Both purified enzymes, MpiAP1 and MpiAP2, were monomeric structures with molecular masses of around 43 and 58 kDa, respectively. The former was an acidic non-glycoprotein, whereas the latter was an acidic glycoprotein with 27% carbohydrate content. Although amino-terminal amino acid sequence analysis of both enzymes (MpiAP1 and MpiAP2) of 20 amino acid length showed over 90% similarity, their amino-terminal amino acids were different from each other. Both enzymes were optimally active at 55 °C and at pH 2.5–3.0 against casein or human haemoglobin. The T_1/2 values of MpiAP1 and MpiAP2 were 65 and 70 °C, respectively. Both of the enzymes were completely inhibited by pepstatin A, and markedly by SDS. MoO₃ also showed a partial inhibition of both enzymes. Milk casein and haemoglobin were good substrates for these enzymes. Eleven cleavages were detected using the oxidised insulin B-chain as a peptide for the proteolytic specificity test of MpiAP1, while seven cleavages were detected for MpiAP2.     

A firm as a knowledge-creating entity: a new perspective on the theory of the firm

The knowledge-based view of the firm views a firm as a knowledge-creatingentity, and argues that knowledge and the capability to createand utilize such knowledge are the most important source ofa firm's sustainable competitive advantage. Knowledge and skillsgive a firm a competitive advantage because it is through thisset of knowledge and skills that a firm is able to innovatenew products/processes/services, or improve existing ones moreefficiently and/or effectively. The raison d'être of afirm is to continuously create knowledge.     

New Pb-Based 1222 Cuprates, (Pb0.5B0.5)Sr2(RE2−x−y Ce x Sr y )Cu2O z (RE = Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, and Y)

New Pb-based layered cuprates with the 1222 structure have been synthesized in the (Pb_0.5B_0.5)Sr₂ (RE_2−x−y Ce _x Sr _y )Cu₂O _z (RE = Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, and Y) systems. The almost-single-phase samples in the systems can be obtained for a nominal composition of x=0.7 and y=0.1. The crystal structure of the samples has a tetragonal symmetry, the lattice parameters of a and c are increasing with increasing the ionic radius of RE element. Despite treatment under high O₂ pressure of 100 atm, the samples are semiconductors with the transport process characteristic of three-dimensional variable range hopping conduction.     

Residual stress versus microstructural effects on the strength and toughness of phase-separated PbO–B2O3–Al2O3 glasses

A few authors have reasonably proposed that liquid–liquid phase-separated (LLPS) glasses could show improved fracture strength, S_f, and toughness, K_Ic, as the second phase could provide a barrier to crack propagation via deflection, bowing, trapping, or bridging. Due to the associated tensile or compressive residual stresses, the second phase could also act as a toughening or a weakening mechanism. In this work, we investigated five glasses of the PbO–B₂O₃–Al₂O₃ system spanning across the miscibility gap: Four of them undergo LLPS—three are binodal (two B₂O₃-rich and one PbO-rich) and one is spinodal—and one does not show LLPS (composition outside the miscibility gap). Their compositions were designed in such a way that the amorphous particles are under compressive residual stresses in some and under tensile residual stresses in others. The following mechanical properties were determined: the Vickers hardness, ball on three balls (B3B) strength, and toughness, K_Ic-SEVNB (single-edge V-notch beam [SEVNB]). The microstructures and compositions were analyzed using scanning electron microscopy with energy-dispersive X-ray spectrometry. The spinodal glass showed, by far, the best mechanical properties. Its K_Ic-SEVNB = 1.6 ± 0.1 MPa m^1/2, which embodies an increase of almost 50% over the B₂O₃-rich binodal composition, and 90% considering the PbO-rich binodal composition. Moreover, its fracture strength, S_f = 166 ± 7 MPa, is one of the highest ones ever reported for an LLPS glass. Fracture analyses evidenced that the spinodal composition exhibited the lowest net stress at the fracture point. Moreover, calculations indicate that the internal residual stress level is the lowest in the spinodal glass. The overall results indicate that the microstructural effect of the spinodal glass is the most significant factor for its superior mechanical properties. This work corroborates the idea that LLPS provides a feasible and stimulating solution to improve the mechanical properties of glasses.