Tensile deformation of amorphous nickel-palladium-phosphorous alloys

Ni-Pd-P amorphous alloys show inhomogeneous plastic deformation, as do all other amorphous alloys. A few localized deformation bands appear macroscopically just beyond the elastic region of the stress strain curve. It is shown that two types of localized deformation bands can be produced during tensile deformation,i.e., one has sharp steps produced by plastic flow associated with a shear, and the other has interconnecting voids similar to a crazing crack in polymers.     

Analysis of field distributions in a GaAs m.e.s.f.e.t. at large drain voltages

Electric-field distributions and carrier-density distributions in a GaAs m.e.s.f.e.t. at large drain voltages are investigated with a new analytical model, which takes account of the electron-drift-velocity saturation with negative differential mobility and the extension of a depletion layer towards the drain electrode.     

Computer-controlled microcirculatory support system for endothelial cell culture and shearing

Endothelial cells (ECs) lining the inner lumen of blood vessels are continuously subjected to hemodynamic shear stress, which is known to modify EC morphology and biological activity. This paper describes a self-contained microcirculatory EC culture system that efficiently studies such effects of shear stress on EC alignment and elongation in vitro. The culture system is composed of elastomeric microfluidic cell shearing chambers interfaced with computer-controlled movement of piezoelectric pins on a refreshable Braille display. The flow rate is varied by design of channels that allow for movement of different volumes of fluid per variable-speed pump stroke. The integrated microfluidic valving and pumping system allowed primary EC seeding and differential shearing in multiple compartments to be performed on a single chip. The microfluidic flows caused ECs to align and elongate significantly in the direction of flow according to their exposed levels of shear stress. This microfluidic system overcomes the small flow rates and the inefficiencies of previously described microfluidic and macroscopic systems respectively to conveniently perform parallel studies of EC response to shear stress.     

Inorganic-organic hybrid molecular architectures of cyanometalate host and organic guest systems: specific behavior of the guests

Molecular architectures built of inorganic cyanometalate building blocks provide variegated host structures with several organic guest molecules. The strategies to derive novel structures are presented briefly. The formation of a charge-transfer (CT) complex as the guest inside the cavity and the photochemistry of the CT complexes are discussed. The chemical pressure that the guest experiences inside the cavity is also discussed based on the vibrational spectroscopic results.     

Mechanical behaviour of partially crystallized amorphous alloys

Deformation and fracture of partially crystallized Ni₅₅Pd₃₅P₁₀ amorphous alloys have been investigated. The samples with a few percent crystallization show a fracture stress (175 kg mm⁻²) and apparent Young's modulus (19.5×10³kg mm⁻²) greater than those completely amorphous or partially crystallized 50%. On the other hand, the fracture strain of the former are lower than those of the two latter. A simulated model with mixtures of carborundum powder with grease, shows accord with morphological and mechanical aspects of the partially crystallized alloys. As expected, microcrystals embedded in an amorphous material act as obstacles to plastic flow.     

Selective and unselective clamping in cirrhotic liver

BACKGROUND/AIMS: Liver surgery requires a reduction of the operative blood loss especially for patients with cirrhosis. Selective or unselective liver clamping during hepatic resection is performed to minimize the surgical risk for such compromised patients. METHODOLOGY: We carried out elective hepatic resection in 158 patients with the use of total hilar clamping (Pringle's manoeuvre) or selective vascular clamping (Makuuchi's manoeuvre). The clinical outcomes were evaluated according to the clamping method and the condition of background liver. RESULTS: Pringle's manoeuvre was used in 132 patients who underwent all types of hepatectomy, whereas Makuuchi's manoeuvre was applied selectively to 26 patients, most of whom underwent segmentectomy or subsegmentectomy. A modified Makuuchi's manoeuvre was used in eight healthy donors who underwent left-sided hepatectomy for transplantation. The cumulative clamping times and blood losses were 61 +/- 47 min (mean +/- SD) and 831 +/- 716 ml in the Pringle's manoeuvre group, and 95 +/- 47 min and 1.035 +/- 577 ml in the Makuuchi's manoeuvre group. In patients with normal hepatic parenchyma the longest clamping time was 322 min, and in those with cirrhosis it was 202 min. All the patients in this series tolerated vascular clamping well, and their hepatic functional parameters returned, regardless of the presence or absence of cirrhosis, to the baseline levels within a week. As a whole, the operative morbidity and mortality rates were 20.3% and 0%, respectively. CONCLUSIONS: Intermittent total or selective clamping can be an indispensable procedure during hepatic resection for all patients, irrespective of the degree of hepatic dysfunction, to improve safety and resectability.     

Development of anchored oligothiophenes on substrates for the application to the tunable transparent conductive films

Bis(triethoxysilyl)-substituted oligothiophene with a moderate π-conjugation length was newly synthesized and polymerized to give a polysilsesquioxane network having oligothiophene units dispersed homogeneously without phase separation. The polymer was fixed on glass or ITO substrate by spin-coating and annealing. The resulting film exhibited a high mechanical strength due to the covalent bonding with the substrates, and was electrochemically stable even after 300 redox cycles in electrolyte solution. Chemical oxidation of the polymer films yielded electrically conductive and almost transparent films.     

Antimicrobial Microwebs of DNA–Histone Inspired from Neutrophil Extracellular Traps

Neutrophil extracellular traps (NETs) are decondensed chromatin networks released by neutrophils that can trap and kill pathogens but can also paradoxically promote biofilms. The mechanism of NET functions remains ambiguous, at least in part, due to their complex and variable compositions. To unravel the antimicrobial performance of NETs, a minimalistic NET‐like synthetic structure, termed “microwebs,” is produced by the sonochemical complexation of DNA and histone. The prepared microwebs have structural similarity to NETs at the nanometer to micrometer dimensions but with well‐defined molecular compositions. Microwebs prepared with different DNA to histone ratios show that microwebs trap pathogenic Escherichia coli in a manner similar to NETs when the zeta potential of the microwebs is positive. The DNA nanofiber networks and the bactericidal histone constituting the microwebs inhibit the growth of E. coli. Moreover, microwebs work synergistically with colistin sulfate, a common and a last‐resort antibiotic, by targeting the cell envelope of pathogenic bacteria. The synthesis of microwebs enables mechanistic studies not possible with NETs, and it opens new possibilities for constructing biomimetic bacterial microenvironments to better understand and predict physiological pathogen responses.     

Skeleton clustering by multi-robot monitoring for fall risk discovery

This paper tackles the problem of discovering subtle fall risks using skeleton clustering by multi-robot monitoring. We aim to identify whether a gait has fall risks and obtain useful information in inspecting fall risks. We employ clustering of walking postures and propose a similarity of two datasets with respect to the clusters. When a gait has fall risks, the similarity between the gait which is being observed and a normal gait which was monitored in advance exhibits a low value. In subtle fall risk discovery, unsafe skeletons, postures in which fall risks appear slightly as instabilities, are similar to safe skeletons and this fact causes the difficulty in clustering. To circumvent this difficulty, we propose two instability features, the horizontal deviation of the upper and lower bodies and the curvature of the back, which are sensitive to instabilities and a data preprocessing method which increases the ability to discriminate safe and unsafe skeletons. To evaluate our method, we prepare seven kinds of gait datasets of four persons. To identify whether a gait has fall risks, the first and second experiments use normal gait datasets of the same person and another person, respectively. The third experiments consider that how many skeletons are necessary to identify whether a gait has fall risks and then we inspect the obtained clusters. In clustering more than 500 skeletons, the combination of the proposed features and our preprocessing method discriminates gaits with fall risks and without fall risks and gathers unsafe skeletons into a few clusters.