Chain stiffness and chain conformation of poly(α-methylene-γ-butyrolactone) in dilute solutions

The chain stiffness and local chain conformation of atactic poly(α-methylene-γ-butyrolactone) (PMBL), which is a side chain cyclic structural analog of poly(methyl methacrylate) (PMMA), with a weight-average molecular weight (M_w) ranging from 2.8 × 10³ to 2.6 × 10⁶ in N,N-dimethylformamide (DMF) and γ-butyrolactone (GBL) were characterized by size exclusion chromatography with a multi-angle light-scattering detector (SEC-MALS) and synchrotron radiation small-angle X-ray scattering (SAXS). Based on the Kratky-Porod worm-like chain model, the scattering functions and the M_w dependence of z-average root-mean-square radius of gyration <S²>_z^1/2 yielded the Kuhn segment lengths λ⁻¹, the diameter of the PMBL chains d, and the excluded-volume strengths in DMF and GBL. The local conformation of atactic PMBL in DMF and GBL were slightly larger than those of atactic PMMA, due to the presence of the conformationally rigid lactone ring structure.     

Full-circular surface acoustic wave excitation for high resolution acoustic microscopy using spherical lens and time gate technology

With a fixed gate width under the condition where the focus of an acoustic lens was set inside the sample, we varied signal taking-in time. Discrimination was made between differences in time required for an ultrasonic signal reflected from the sample to reach the acoustic lens. This process also enabled three types of images to be obtained separately: the surface reflection wave image, a combination of images based on the interference of the surface reflection wave with surface acoustic waves, and the surface acoustic wave image. Thus it was presumed that this process also would reveal the causes of image contrast and allow an easy interpretation of images. Furthermore, the image resolution was improved, because the surface acoustic wave image was drawn by an ultrasonic beam produced by full-circular surface acoustic wave excitation propagating toward the center converging concentrically; the theoretical resolution was 0.4 times the value of the surface acoustic wave wavelength lambda(R) and independent of the defocus value of the acoustic lens. Several kinds of samples were observed with this method. The results showed that the new method permitted observation of the internal structures of samples while offering new knowledge through the data reflecting the ultrasonic wave damping and scatter drawn on the display.     

Intra-body data transmission for the personal area network

Intra-body communication is a wireless means of exchanging information within a personal area network (PAN) between wearable electronic sensors and devices. The feasibility of intra-body communication is confirmed through several experiments on signal propagation within the human body, and a human phantom is designed and used to obtain reproducible results over repeated experiments. Based on the results of these experiments, a prototype transmission system is constructed using aluminum electrodes powered by 3 V DC and operating in the 10.7 MHz frequency modulation (FM) band. This prototype is demonstrated to be capable of transmitting analog signals through the human subjects in the presence of external noise. Digital data transmission at 9600 bps is also achieved using newly fabricated 10.7 MHz frequency shift keying (FSK) transmitter and receiver devices. The carrier frequency of 10.7 MHz is the intermediate frequency of FM radio receivers, meaning that the proposed system can make use of a wide selection of inexpensive, commercial radio frequency devices.     

Status and research programs of the multinuclide accelerator mass spectrometry system at the University of Tsukuba

We present the current status and research programs of a multinuclide accelerator mass spectrometry (AMS) system on the 12UD Pelletron tandem accelerator at the University of Tsukuba (Tsukuba AMS system), Japan. A maximum terminal voltage of 12 MV is available for the AMS system. The Tsukuba AMS system can measure environmental levels of long-lived radioisotopes of ¹⁴C, ²⁶Al, ³⁶Cl and ¹²⁹I by employing a molecular pilot beam. Recently, enhancements in AMS techniques and equipment, including sample preparation, the ion source and the data acquisition system, have improved the performance of ³⁶Cl-AMS. The standard deviation of fluctuations is typically ±2%, and the machine background level for the ³⁶Cl/Cl ratio is lower than 1 × 10^?15 with a halite sample. We have measured over 500 samples in 1 year, including samples for earth and environmental sciences and nuclear safety research.     

Pathological consideration of a "blister-like" aneurysm at the superior wall of the internal carotid artery: case report

OBJECTIVE AND IMPORTANCE: Although the incidence is low, a very small aneurysm with a thin wall and no neck arises at the superior wall of the supraclinoid portion of the internal carotid artery and is called a "blister-like" aneurysm. However, the pathogenesis of such a vascular lesion remains uncertain. CLINICAL PRESENTATION: A 57-year-old man developed a fatal subarachnoid hemorrhage caused by the rupture of a blister-like aneurysm at the superior wall of the internal carotid artery. An autopsy was performed, and the lesion was pathologically examined. RESULTS: The internal elastic lamina and media had disappeared at the border between the eccentrically sclerotic and normal carotid wall. The gap in the internal elastica was covered with normal adventitia and fibrinous tissue. This portion was not composed of collagenous tissue as ordinarily seen in an aneurysmal wall. Neither infiltration of inflammatory cells nor dissection of the artery were observed. CONCLUSION: The blister-like aneurysm appeared to be a laceration of the carotid wall based on degeneration of the internal elastic lamina.     

Expression of carbohydrate antigen sialyl Le(a): a new functional prognostic factor in gastric cancer

PURPOSE: The prognostic value of the altered expression of carbohydrate antigens sialyl Le(a) (sLe(a)) and sialyl Le(x) (sLe(x)), which have been implicated as functional ligands in heterotypic-cell-adhesion systems in the multistep process of tumor metastasis, were evaluated. PATIENTS AND METHODS: The level of expression of sLe(a) and sLe(x) antigens was examined immunohistochemically in paraffin-embedded tumor samples from 137 patients who underwent resection for gastric cancer. Correlation between the antigens' expression, various established clinicopathologic factors, and prognosis were studied by univariate and multivariate analysis. RESULTS: Tumors that were positive for the sLe(a) antigen were significantly more likely to be large (P = .035), to be localized at the proximal third of the stomach (P = .018), to have an infiltrate appearance (P = .013), to have an invasive mode both in depth of invasion (P = .028) and in lymphatic invasion (P = .002), and to be classified as late stage (P = .011) than those that were negative for sLe(a), whereas the sLe(x) antigen status was not correlated with any clinicopathologic factors. The overall survival of patients with an sLe(a)-antigen-positive tumor was significantly poorer than that of those with an sLe(a)-antigen-negative tumor (P = .0001). Survival within each pathologic stage differed also (stage I, P = .030; stage II, P = .046; stage III, P = .026, respectively). A Cox regression analysis with multiple covariates showed that positive sLe(a) antigen status was an independent prognostic factor for a worse outcome in patients with gastric cancer. According to the mode of recurrence, increased sLe(a) antigen expression significantly affected both peritoneal dissemination and liver metastasis. CONCLUSION: Increased expression of the sLe(a) antigen may serve as a potent prognostic indicator for recurrence in patients with gastric cancer. Careful follow-up and intensive therapy are required for patients with an sLe(a)-antigen-positive gastric cancer.     

Development of a geographical information system and its application to Escherichia coli O-157 patient distribution

The so called Geographical Information System (GIS) is one of the basic tools for wide range of public health applications. We had developed a general purpose GIS and applied it to represent geographical distribution of patients of the bacterium E. coli O-157 which bursted out in Japan last early summer particularly at Sakai City in Osaka Prefecture. The patient record have been supplied from the Food Safety Office of the Ministry of Health and Welfare. These records were handled by EXCEL. The basic geographical data was constructed from the map data provided by Japan Geographical Survey Institute, and ArcView 2 was used as the map system. The maps were converted to Graphics Interchange Format (GIF) files and put on our Web server.     

Discordant splenic uptake of Tc-99m colloid and Tc-99m denatured RBC in candidiasis-endocrinopathy syndrome

The aim of this study was to estimate the incidence of melanoma in the Paris region in 1994 and analyse the main clinical and histological characteristics of these lesions. It took the form of a prospective inquiry, mailed to public and private pathology laboratories, to count as accurately as possible the number of new cases diagnosed by pathologists in the region during the 1994 calendar year. In all, 1089 newly diagnosed Clark level I to V melanomas (excluding precancerous melanosis of Dubreuilh) were studied. Parameters recorded included age, sex, Clark level and Breslow's thickness. The incidence per 100,000 inhabitants was 9.93 for melanoma and 8.62 for invasive melanoma. The female to male ratio was 1.6. Clark level I or thin (< 0.75 mm) melanomas represented 64.8% of the lesions. At the time of diagnosis, the females were significantly younger than the males (P = 0.004). Breslow's thickness increased with age and was significantly lower in women (P = 0.00005), especially those between 40 and 49 years old. The incidence of melanoma in the Paris region in 1994 was close to that observed during the preceding 5 years in England, Scotland and the French department of Haut-Rhin. It was 2.32 times higher for males and 1.69 times higher for females than the rates estimated for France for the period 1978-1982.     

Prediction of spinal cord ischemia with a retrievable stent graft on endovascular treatment for a case of thoracic aortic aneurysm

OBJECTIVE: To determine the pharmacokinetics and absolute bioavailability of ciprofloxacin in 12 critically ill patients receiving continuous enteral feeding. Design: a prospective, cross-over study. SETTING: 12-bed surgical intensive care unit in a University Hospital. PATIENTS: 12 stable critically ill patients on mechanical ventilation and receiving continuous enteral feeding (Normoreal fibres) without diarrhea or excessive residual gastric contents ( < 200 ml/4 h). None had gastro-intestinal disease, renal insufficiency (estimated creatinine clearance > or = 50 ml/min) or was receiving medications that could interfere with ciprofloxacin absorption or metabolism. MEASUREMENTS AND MAIN RESULTS: The study was carried out after the fourth (steady state) b. i. d. intravenous (i. v.) 1-h infusion of 400 mg and the second b. i. d. nasogastric (NG) dose of 750 mg (crushed tablet in suspension). Plasma concentrations were measured by high-performance liquid chromatography. The median (range) peak concentration after i. v. infusion was 4.1 (1.5-7.4) mg/l, and that after NG administration was 2.3 (0.7-5.8) mg/l, occurring 1.25 (0.75-3.33) h after dosing. The median [range] areas under plasma concentration-time curves were similar for the two administration routes (10.3 [3.3-34.6] and 8.4 [3.6-53.4] for i.v. infusion and NG administration, respectively). Ciprofloxacin bioavailability ranges from 31 to 82 % (median, 44%). CONCLUSIONS: In tube-fed critically ill patients, a switch to the NG ciprofloxacin after initial i. v. therapy to simplify the treatment of severe infections is restricted to those for whom serial assessments of ciprofloxacin levels are routinely available.     

Study on environmental effect on fatigue and creep-fatigue strength of 316FR stainless steel in sodium at elevated temperature

Low-carbon 316 stainless steel with medium-nitrogen (316FR) is considered as the principal structural material for next generation fast breeder reactor (FBR) plants in Japan. The material strength standard and the creep-fatigue life evaluation method for 316FR have been developed. However, they are based on the results of material tests in air, while actual structural material will be used mainly in liquid sodium environment in the plants. In order to clarify the environmental effect, cyclic bending tests were carried out with and without hold time in sodium. Tested materials were 316FR and conventional 304 and 316 stainless steels. Weld metal of 316FR was also tested. As a result, it was found that fatigue and creep-fatigue lives of 316FR in sodium were larger than those in air and no explicit consideration of the environmental effect is necessary in design. It was also found that the life evaluation method based on the ductility exhaustion concept is applicable to creep-fatigue life assessment in sodium.