Relation of saphenous vein graft obstruction to serum cholesterol levels

Thirty patients with symptomatic colorectal carcinoma were commenced on treatment with 5-fluorouracil (2.5 g week-1) administered by continuous intravenous infusion and alpha 2b interferon (3 x 10(6) U s.c. three times a week). Six out of 30 patients (20%) achieved a partial response. Three patients (10%) had stable disease and 21 patients (70%) progressed on treatment. Twenty patients (67%) completed ten or more weeks of treatment. In nine patients, treatment was withdrawn after 2-9 weeks because of disease progression or death. One patient's treatment was interrupted by emergency surgery. The median survival for all patients was 210 days (7 months). The principal side-effects were oral mucositis (12/30 patients), nausea (8/30 patients) and transient diarrhoea (4/30 patients), and initial constitutional symptoms due to alpha 2b interferon. The combination of low-dose continuous infusional 5-fluorouracil and low-dose alpha 2b interferon is well tolerated but has no obvious advantage over alternative infusional regimens using 5-fluorouracil as a single agent.     

Prevention of accomplishing synchronous multi-modal human–robot cooperation by using visual rhythms

Effective rhythm expression (ERE) from a robot to a human performing a multi-modal physical-cooperation (MMPC) task was accomplished. During MMPC, the participant and the robot can exchange various rhythms between themselves. To accomplish ERE, it is important to appropriately select the modalities in which the robot expresses its desired rhythm. Accordingly, a hypothesis that selecting the visual rhythm for RE prevents MMPC was tested and confirmed. This hypothesis was preliminarily confirmed in regard to MMPC between two humans. Moreover, to confirm the hypothesis in regard to human–robot cooperation, an experimental system (including a rope-turning robot) was developed. This experimental system allowed experimenters to evaluate the synchronization during MMPC between a human and a robot by measuring the norm of angular velocities. The results of several experiments (namely, a comparison of norms), in which several combinations of visual and auditory rhythmic stimuli were presented to the subjects, strongly supported the hypothesis.     

Casting Manipulation—Midair Control of a Gripper by Impulsive Force

We have developed a casting manipulator that includes a flexible light string in the link mechanism to enlarge the workspace of the manipulator. In the casting manipulation, an end-effector is launched to its target by releasing the string connected to it, and its trajectory is controlled by the tension of the string. In this paper, we present the midair control of the end-effector. As a simple way, we propose the braking technique to apply impulsive force to the end-effector by braking the movement of the string. Examining dynamic characteristics of the string when an impulsive force applies to it, we show that the midair motion of the end-effector can be controlled by the braking technique. Then, we apply the braking technique to the multiple braking control of the trajectory. We confirm the effectiveness of the proposed method through simulations and experiments using casting manipulator hardware.     

ORR performance evaluation of Al-substituted MnFe2O4/ reduced graphene oxide nanocomposite

Active and durable oxygen reduction reaction (ORR) catalysts are of utmost importance to realize the commercialization of hydrogen fuel cells and metal-air batteries. Al-substituted MnFe₂O₄-based ternary oxide and reduced graphene oxide (MAF-RGO) nanocomposite is synthesized using an in-situ co-precipitation followed by a hydrothermal process and verified for ORR electrocatalysis in the alkaline electrolyte (0.1 M KOH). MAF-RGO is first analyzed using physicochemical characterization tools including X-ray diffraction, Raman spectroscopy, sorption studies, electron microscopy, X-ray photoelectron spectroscopy, etc. Further, the characteristic ORR peak centered at 0.56 V vs. reversible hydrogen electrode (RHE) in cyclic voltammetry (CV) studies confirms the electrocatalytic performance of MAF-RGO. The ORR onset potential of 0.92 V vs. RHE is obtained in linear sweep voltammetry (LSV) measurement at 1600 rpm in O₂-saturated electrolyte exhibiting an improved ORR performance as compared to the commercial electrocatalyst. The reduction kinetics is observed to follow the desirable near 4-e^- mechanism. In addition, the electrocatalyst exhibits improved relative current stability of 86% and methanol poisoning resistance of 82%, which is better in comparison to the standard Pt/C. The observed electrochemical performance results from the synergism between the oxygen vacancy-rich Al-substituted metallic oxide active species and the functional group enriched predominantly mesoporous RGO sheets with excellent electrical conductivity. The introduction of metallic species enhanced the inter-planar spacing between graphitic sheets easing the maneuver of reactant species through the electrocatalyst and accessing more ORR-active sites. This study establishes the potency of mixed transition metal oxide/nanocarbon composites as durable high-performance ORR-active systems.     

Mechanochemically assisted hydrothermal synthesis of Sn-substituted MFI-type silicates

Substitution of Al atoms in a zeolite framework by catalytic metal atoms has attracted considerable attention because the catalytic behavior can be tuned by the substituted atoms. In the present study, Sn-substituted MFI-type silicates were synthesized using a hydrothermal reaction of an amorphous Si-O-Sn precursor prepared by mechanochemical grinding of SiO₂ and Sn(OH)₄. The mechanochemical treatment was found to be a key technique for obtaining the amorphous Si-O-Sn precursor, where tetrahedral Sn⁴⁺ species were incorporated into the amorphous matrix. The Sn content in the framework of the MFI-type silicates was successfully controlled by the initial HCl/Si molar ratio of the hydrothermal procedures. Optical reflectance measurements revealed that the Sn⁴⁺ ions were dispersedly incorporated into the silicate framework while preserving the initial tetrahedrally coordinated species. Infrared results imply that the resulting Sn-substituted MFI-type silicate has Brønsted acid character. Precise control of the Brønsted and Lewis acid properties by Sn doping is a promising approach to the development of novel types of zeolite-based catalytic materials.     

Ductile-to-brittle transition in tensile failure due to shear-affected zone with a stress-concentration source: a comparative study on punched-plate tensile-failure characteristics of precipitation-hardened and dual-phase steels

The effect of shear-affected zone (SAZ), with a stress-concentration source induced by the punching process, on tensile properties was investigated. Tests using honed specimens (which have the same shapes and stress-concentration without any SAZ) and smooth specimens were conducted to compare the effect with that of the punched specimens. Dual-phase steel, which has a high work-hardening ability and low yield strength, and precipitation-hardened steel, which has a low work-hardening ability and high yield strength, were used in the tests. Materials with two tensile strength grades were prepared from both types of steel. Only the precipitation-hardened steel with higher strength grade punched specimen showed a brittle fracture with extremely short fracture-elongation, whereas the other specimens showed a ductile fracture. The fracture surface analysis revealed that cracks initiated in the maximum shear stress plane of the SAZ under tensile loading at first. We call the crack “shear crack.” The steel which showed brittle fracture used in this study easily exhibited plastic-strain localization compared with the other steels. If the shear crack is sharp, then the transition from ductile to brittle failure tends to occur. Furthermore, the strength characteristics of the punched specimen depend on the crack length dependency of the strength resistance and the failure phenomenon of the original material.     

Dissolved iron and its speciation in a shallow eutrophic lake and its inflowing rivers

It has been suggested that iron is a limiting factor on bloom-forming cyanobacteria in lake water. Although the availability of iron for phytoplankton depends significantly on its speciation, little is known about iron speciation in natural lake water. We investigated the horizontal distribution and temporal variation of dissolved iron and its chemical speciation in Lake Kasumigaura and its two inflowing rivers. Concentrations of dissolved iron and its organic ligands, determined by cathodic stripping voltammetry, clearly decreased as lake water flowed from the river entry points toward the center of the lake, indicating their riverine origin. The fraction of iron occurring in organic complexes tended to increase with the water flow. These results suggest that most of the dissolved iron in river water forms unstable soluble species, such as inorganic iron; thus, these unstable iron species may be scavenged in the mouths of rivers, and stable organic complexes of iron may flow to the center of the lake. Furthermore, most of the dissolved iron (88.2-99.9%) was present as organic complexes, and the inorganic iron level in Lake Kasumigaura (pFe' value=7.8-13.6) was similar to that observed in the open ocean. This result suggests that iron is an important factor determining the structure of the phytoplankton community in Lake Kasumigaura.     

Color category influences heterogeneous visual search for color

Many previous studies have revealed chromatic characteristics of visual search using relatively simple stimuli. They suggested that color difference between a target and distractors was a crucial factor. However, it may not be applicable to natural environments that contain numerous colors. This study demonstrates the existence of a color-category effect on heterochromatic visual search. Color differences between a target and distractors were constant in the OSA uniform color scales; however, the search times varied widely. This suggests that color differences alone do not explain search performance. To clarify the mediation of a higher-order categorical color process, search times were analyzed using 11 basic colors. When the color category of a target was shared by a larger number of distractors, the search performance declined. However, when the color category of a target was not shared with distractors, the target was easily detected. The results suggest that heterochromatic stimuli could be segregated by categorical color perception.