Temperature distribution in Li2O pellets under neutron irradiation

The center temperature of Li₂O pellets under neutron irradiation was measured using an encapsuled pin. The surface temperatures of the pellets and the pellet/cladding heat transfer coefficients were estimated on the basis of the well-known conductivity integral.     

A canalicular multispecific organic anion transporter (cMOAT) antisense cDNA enhances drug sensitivity in human hepatic cancer cells

The human cMOAT gene encodes a membrane protein involved in the ATP-dependent transport of hydrophobic compounds. To determine whether cMOAT is associated with drug sensitivity, we transfected an expression vector containing cMOAT antisense cDNA into the HepG2 human hepatic cancer cell line. We observed a reduction in cMOAT protein, as well as an enhanced level of glutathione, in the antisense transfectants. The transfectants displayed an increased sensitivity to cisplatin, vincristine, doxorubicin, and the camptothecin derivatives, (4S)-4,11-diethyl-4-hydroxy-9-[(4-piperidinopiperidino)carbonyl oxy]dione hydrochloride triethydrate and 7-ethyl-10-hydroxycamptothecin, but not to etoposide, 3-[4-amino-2-methyl-5-pyrimidinyl)methyl]-1-(2-chloroethyl)-1-nitrosoure a, 5-fluorouracil, and mitomycin C. Results suggest that cMOAT levels are inversely correlated with those of glutathione, and that cMOAT and its related genes may be involved in the sensitivity of cells to certain anticancer agents.     

The effect of boundary conditions on experimentally measured trabecular strain in the thoracic spine

Vertebral bodies are the primary structural entities of the spine, and trabecular bone is the dominant material from which vertebral bodies are composed. Understanding the mechanical characteristics of vertebral trabecular bone, therefore, is of critical importance in the many clinical conditions that affect the spine. Numerous studies have loaded vertebral bodies to investigate the influence of trabecular bone characteristics on deformation and failure patterns, but the methods of load application have been inconsistent. These differences in the method of load application are a potential confounding factor in the interpretation of the experimental results. We investigated this problem by measuring the distribution of minimum principal strain and maximum shear strain magnitude within 6.35 mm thick samples cut from thoracic spine segments (T8-T10) and loaded to simulate three common experimental configurations. Measurements were made using the texture correlation technique, which extracts deformation patterns from digitized contact radiographs of samples under load. The three loading configurations examined were a three-body construct, a single vertebral body loaded through sectioned intervertebral discs, and polymethylmethacrylate molded directly to the endplates. Results indicate that from both probability and spatial distribution standpoints the best simulation of in vivo loading generates the least uniform strains. Loading through disc remnants or through plastic molded to the endplates causes increasing degrees of strain homogenization. This result has implications not only for the design of experiments involving spinal loading, but also for theories concerning the adaptation of trabecular bone to functional loads.     

Long-term results of preoperative hyperthermo-chemo-radiotherapy (HCR) for patients with esophageal carcinoma invading neighboring structures (T4)

PATIENTS: A total of 180 patients with esophageal carcinoma invading the neighboring structures (T4) were surgically treated by esophagectomy and reconstruction in the Department of Surgery II, Kyushu University from January 1965 to April 1997. Any of these cases with distant node metastasis and demonstrating organ metastasis or a combined resection of adjacent structures were excluded from this study. As a result, twenty-six patients treated with preoperative hyperthermo-chemo-radiotherapy (HCR Group), 39 treated either with preoperative radiotherapy or preoperative chemo-radiotherapy (R or CR Group) and 23 non-treated patients (Non-tx Group) were thus entered in this study. RESULTS: The 3-year survival rates after esophagectomy in HCR Group, R or CR Group and Non-tx Group were 26.5%, 0% and 9%, respectively, while the 5-year survival rate of the HCR group was 15.9%. The group with preoperative HCR thus showed a significantly more favorable outcome than R or CR Group and Non-tx Group. (p < 0.05). DISCUSSION: The significant difference observed in the prognosis was thought to be due to the reinforced effect of local regulation due to hyperthermia. Our data thus suggest that preoperative HCR contributes to the prolonged post-operative survival for carcinoma of the esophagus invading the neighboring structures.     

Compatibility between several heat resistant alloys and sintered Li2O in static helium gas environment

The reaction of sintered Li₂O discs with several commercial heat resistant alloys has been investigated under the conditions of 3.3 × 10⁴Pa ($\text{1}\text{3}\text{atm}$) static He gas atmosphere in the temperature range of 500 and 750° C. Reaction products were identified by X-ray diffraction analysis to be two phases of Li₅FeO₄ and LiCrO₂. The former was dominant below 650° C and the latter was dominant above 650° C. The activation energies of the reaction were determined by the Arrhenius plots for weight changes and sub-scale thickness measurements. The reactivity of the four Fe-Ni-Cr alloys decreased according to the order of Incoloy 800, 316 SS, Hastelloy X-R and Inconel 600. Grain boundary penetration was observed above 500° C for Incoloy 800, 550° C for 316 SS and 600° C for Inconel 600. There was no grain boundary penetration in Hastelloy X-R.     

One-point method for determination of number-average molecular weight

The following well-known equation permits the ready determination of M _n from a single osmotic pressure measurement at a known concentration, if the second virial coefficient is previously given: On this basis, the one-point method was investigated to determine the number-average molecular weight. It was found that this method was applicable to commercial polymers. However, in this application, the dependence of Γ₂ on molecular weight distribution has to be kept in mind.     

铜引线键合中影响焊球硬度因素的研究

铜丝球焊由于其经济优势和优越的电气性能近来得到了普及,然而,在引线键合工艺中用铜丝取代金丝面临着一些技术上的挑战。多年来,IC芯片焊盘结构已经逐步适应了金丝球焊。铜在本质上比金硬度高,因此以铜线取代金线便引出了有关硬度的问题。研究了用25．4μm铜丝球焊中与键合机参数有关的铜焊球硬度特性。采用电子打火系统不同的电流和打火时间设置,用5％氢气和95％氮气组成的惰性保护气体形成了一个典型的25．4μm大小的铜焊球,研究了维氏硬度的焊球。用实验设计建立了第一和第二键合参数,进行了无空气焊球基本数据调整。通过改变电子打火系统参数。对硬度特性进行了进一步的测试。典型的键合球的大小和厚度的第一键合响应证实铜键合球的生产实力与电子打火系统的电流和打火时间有关．     

Structural color films with lotus effects, superhydrophilicity, and tunable stop-bands

The structural blue color of a Morpho butterfly originates from the diffraction of light and interference effects due to the presence of the microstructures on the wing of the butterfly. Structural color on the surface of a damselfish reversibly changes between green and blue. Inspired by these creatures, we have been trying to prepare high-quality and functional structural color films. We describe our efforts in this Account. A useful technique to prepare such structural color films in colloidal solution is a "lifting" method, which allows us to quickly fabricate brilliant colloidal crystal films. The thicknesses of the films can be controlled by precisely adjusting the particle concentration and the lifting speed. Moreover, in order to prepare a complicated structure, we have used template methods. Indeed, we have successfully prepared the inverse structure of the wing of a Morpho butterfly with this technique. Initially, however, our structural color films had a whitish appearance due to the scattering of light by defects in the colloidal crystal film. Later, we were able to prepare a non-whitish structural color film by doping an appropriate dye in the colloidal particles to absorb the scattering light. In addition to the structural blue color, the wing of the Morpho butterfly has superhydrophobic properties. According to Wenzel's equation, the hydrophobic and hydrophilic properties are enhanced when the roughness of the hydrophobic and hydrophilic surface is increased, respectively. Based on this mechanism, we have successfully prepared structural color films with superhydrophobic properties, as well as with superhydrophilic properties. Another important property that can be seen in nature is tunable structural color, such as the color change that can be seen on the surface of a damselfish. In order to mimic such color change, we have developed several tunable structural color films. In particular, we have successfully prepared phototunable photonic crystals using photoresponsive azobenzene derivatives. In order to apply these structural color films, we developed a technique for patterning them by taking advantage of the wettability of the substrate surface. These materials can be used in the future for self-cleaning pigments and tunable photonic crystals.