Recent trend on the development of new anticancer drugs

More than 35 candidate drugs have been under their clinical studies in Japan currently. These include antimetabolites, drugs originated from natural products, miscellaneous compounds and hormones. Since the time of appearance of cisplatin and taxol, we found the possibility to discover new active drugs against human solid cancers. Our recent clinical studies on topoisomerase inhibitors and microtubules inhibitors have also been proving the clinical usefulness of these drugs for cancer treatment. From now on, we have to think the drug development from ethical aspects, improving quality of life and prolonging the survival of the treated patients. For these purposes, we have to be careful to choose candidate drugs for their clinical trials.     

Bacterial colonization of the upper respiratory tract of patients with primary lung cancer and nonmalignant lung disease

We examined the bacterial colonization of the upper respiratory tract of 110 patients with primary lung cancer (PLC), 75 patients with nonmalignant lung diseases (NMLD) and 45 healthy volunteers (HV), comparing the sensitivity of expectorated sputum, and throat and nasal swabs. The frequency of bacterial colonization of the upper respiratory tract was significantly higher in the PLC patients (59.1%) than in NMLD patients (37.3%, p < 0.01) and HV (37.8%, p < 0.01). The frequency of gram-negative colonization was significantly higher in PLC patients than in the other subjects (p < 0.01). Expectorated sputum and nasal swab were the most sensitive for detection of whole bacteria and methicillin-resistant Staphylococcus aureus in the patients with PLC. Our results showed that PLC patients are significantly more frequently colonized by bacteria in their upper respiratory tracts and that a combination culture of expectorated sputum and nasal swab is suitable to estimate the bacterial colonization of the upper respiratory tract in the patients.     

Hetero-epitaxial growth of zinc electrodeposits on low-carbon steel sheets

Crystallographic aspects of the electrodeposition of zinc on low-carbon steel sheets have been examined with particular emphasis on the hetero-epitaxy. The hetero-epitaxial growth of zinc crystals largely depends on the surface condition of the ferrite substrate and occurs even at a current density as high as 2 A cm^–2 by reducing the surface oxidation layer. The surface roughness of the substrate induces local disturbance in hetero-epitaxial growth. The orientation relationship between zinc crystals and the ferrite substrate can be interpreted in terms of the minimum misfit atomic arrangements between both phases.     

InGaAs quantum dots formed in tetrahedral-shaped recesses on GaAs (111)B grown by metalorganic chemical vapor deposition

Novel semiconductor quantum dots (QDs), grown in tetrahedral-shaped recesses (TSRs) formed on a (111)B GaAs substrate, are described from both material science and device application points of view. After explaining the fabrication procedure for TSRs, growth of InGaAs QDs and their optical properties are explained. It is revealed that an InGaAs QD of indium-rich chemical composition is formed spontaneously at the bottom of each TSR. The mechanism of the QD formation is discussed in detail. It is proved from magneto-photoluminescence that the QDs actually have optical properties peculiar to zero-dimensional confinement. Several experimental results indicating excellent growth controllability of the QDs are presented. Finally, recent challenges to apply the QDs to electronic memory devices are reported. Two kinds of devices, where the position of individual QD is artificially controlled, are proposed for the first time and the preliminary experimental results are explained.     

Quadruped walking robots at Tokyo Institute of Technology

I(Hirose) was walking along a mountain path near Mt. Fuji on a summer day of 1976, when I found a daddy long-legs walking on the ground. I picked it up in my palm and allowed it to walk over my fingers, and the bug walked effortlessly even over finger-made obstacles ten times larger than its own body. While I was watching the motion of the bug, I started to have the desire to make bigger multilegged walking robots, which can walk over large buildings. This was the beginning of our study of walking robots, which was to last for more than 30 years.     

Enzyme electrode based on gold-plated polyester cloth

Summary Diaphorase is immobilized on electrodes derived from metal-plated polyester cloth by entrapment method and coupled with an electron mediator. Cyclic voltammogram depended on the existence of the substrate NADH (for oxidation) or NAD⁺ (for reduction) and the flavo-enzyme was shown to exchange electron(s) with the cloth electrode by mediation of the ferrocene derivative (for oxidation cycle) or the viologen derivative (for reduction cycle), even in the immobilized state. Coupling of the NADH or NAD⁺ regenerating system with alcohol dehydrogenase was examined.     

Soft and Self-Adhesive Thermal Interface Materials Based on Vertically Aligned,Covalently Bonded Graphene Nanowalls for Efficient Microelectronic Cooling

Urged by the increasing power and packing densities of integrated circuits and electronic devices, efficient dissipation of excess heat from hot spot to heat sink through thermal interface materials (TIMs) is a growing demand to maintain system reliability and performance. In recent years, graphene-based TIMs received considerable interest due to the ultrahigh intrinsic thermal conductivity of graphene. However, the cooling efficiency of such TIMs is still limited by some technical difficulties, such as production-induced defects of graphene, poor alignment of graphene in the matrix, and strong phonon scattering at graphene/graphene or graphene/matrix interfaces. In this study, a 120  µ m-thick freestanding film composed of vertically aligned, covalently bonded graphene nanowalls (GNWs) is grown by mesoplasma chemical vapor deposition. After filling GNWs with silicone, the fabricated adhesive TIMs exhibit a high through-plane thermal conductivity of 20.4 W m⁻¹ K⁻¹ at a low graphene loading of 5.6 wt%. In the TIM performance test, the cooling efficiency of GNW-based TIMs is ≈ 1.5 times higher than that of state-of-the-art commercial TIMs. The TIMs achieve the desired balance between high through-plane thermal conductivity and small bond line thickness, providing superior cooling performance for suppressing the degradation of luminous properties of high-power light-emitting diode chips.     

Instrument for Measuring the Body Mass of Astronauts Under Microgravity Conditions

An improved prototype of the space scale, which has been proposed as a practical and lightweight instrument for measuring the body mass of astronauts under microgravity conditions in the International Space Station (ISS), has been developed. A prominent feature of the proposed instrument is the use of a bungee cord as the source of force. This results in a simple, lightweight, and compact structure of the instrument. It also results in a large displacement during the measurement and then the reduction of the effect of change in subject posture. The feasibility of the prototype design has been evaluated by quantifying the body mass of a human subject in a parabolic flight test. The present and future statuses of the space scale are discussed.     

Effect of growth conditions on advantages of hup− strain for H2 photoproduction by Rubrivivax gelatinosus

H₂ photoproduction by growing cultures of hup^? mutant and parental strain RL2 of Rubrivivax gelatinosus was compared. We checked the influence of different substrates, presence of air and N₂, culture shaking, inoculum concentrations. At low inoculum concentration, hup^? strain demonstrated significant advantage over the parental strain in microaerobic conditions, while under N₂–Ar atmosphere it was lower and vanished in anaerobic conditions (Ar only). This advantage was evident when using substrates with low degree of reduction (malate and succinate). Culture shaking under microaerobic conditions and in presence of N₂ completely prevented H₂ production by both strains. The high inoculum concentration inhibited H₂ production under microaerobic conditions and in presence of N₂, unlike to anaerobic conditions. With inoculum concentration increase, H₂ production decreased not gradually but stepwise which means some metabolic shift. H₂ production by hup^? strain seems to be more tolerant to air traces than by parental strain.