Preparation of poly(N-isopropylacrylamide) grafted silica bead using hyperbranched polysiloxysilane as polymer brush and application to temperature-responsive HPLC

Hyperbranched polysiloxysilane (HBPS) terminated by the vinyl functional group was synthesized by the self polymerization of AB₂ monomer, 1,5-divinyl-1,1,3,5,5-pentamethyltrisiloxane, in the presence of the platinum catalyst. The terminal vinyl group was converted to 2-hydroxyethyl by the reaction with 9-BBN as the hydroboration reagent. The terminal function was then modified to the 2-bromoisobutyryl group by the reaction of hydroxyl group with 2-bromoisobutyryl bromide. The obtained HBPS possessing the 2-bromoisobutyryl terminal group was immobilized on the silica surface by mixing the silica bead and HBPS in hexane. Block copolymer of HBPS and poly(N-isopropylacrylamide) (PIPAAm) was synthesized by the atom transfer radical polymerization (ATRP) using 2-bromoisobutyryl terminated HBPS as a macroinitiator. The molecular weight of the block copolymer was M_n=23,500 and M_w/M_n=1.31. Graft polymerization of N-isopropylacrylamide on the silica surface was carried out on the 2-bromoisobutyryl terminated HBPS immobilized silica bead using ATRP. The PIPAAm grafted silica bead was applied to the column packed material for temperature-responsive HPLC. Two kinds of steroids, hydrophilic and hydrophobic, were successfully separated by the HPLC system.     

The Fatty Acid Composition in Tuna (Bonito,Euthynnus pelamis) Caught at Three Different Localities from Tropics to Temperate

The present paper describes the effect of habitat on the fatty acid composition of the lipid of bonito (Euthynnus pelamis), which was caught at three different localities, Philippine Sea (the tropical zone; seawater temperature at the fishing ground was 27·8°C), East China Sea (the subtropical zone; seawater temperature was 29·7°C), and the Pacific coast of Japan (the temperate zone; sea-water temperature was 20·3°C). The total lipids of various organs and stomach contents were extracted and their fatty acid composition analysed by gas chromatography (GC). Docosahexaenoic acid (DHA; 22: 6n-3) was the major unsaturated fatty acid in the lipid of all specimens examined from all localities. The mean DHA content accounted for more than 25% (mean±standard error: 26·0±0·6%) of the total fatty acids (TFA) in the lipids of all organs, a lipid profile markedly different from that of other fish species whose fatty acid composition is generally variable. Particularly, the mean DHA content of lipids in bonito caught in the northern sea-area sample (the temperate zone) was always high (28·4±0·7% TFA) in the lipid of every organ. Because the DHA contents of lipids of the stomach contents fluctuated between 9·9 and 31·9% TFA, bonito did not simply incorporate the fatty acid profile of the lipids of its prey fishes, but selectively accumulated the DHA. Though the mean DHA content in the lipid of all bonito from the tropical to the temperate zone was markedly higher than other marine fish species such as sardines and herrings, there was a small difference between those in the northern (28·4±0·7% TFA) and southern samples (the subtropical and tropical samples, 24·7±0·8% TFA) (P<0·05). It is suggested that the difference between them may be due to environmental effects, for example, the temperature of the seawater and the fatty acid composition of the lipids of prey organisms. © 1997 SCI.     

Transient gene expression in guard cell chloroplasts of tobacco using ArF excimer laser microablation

In this paper, we report a novel method for delivering genes into chloroplasts of tobacco cells using laser microablation. The plasmid pLD200-GFP was introduced into chloroplasts of Nicotiana tabacum cv. Xanthi guard cells and transient GFP expression was detected in the chloroplasts after 2-3 d of incubation. The technique uses an argon fluoride (ArF) excimer laser to perforate the cell surface in a 4 mum(2) area in the presence of plasmid coated gold microparticles. Pretreatment of guard cells to promote stomatal closure prior to laser ablation resulted in a significant increase in the survival rate of cells and a transient expression rate of 2-3% in trial number basis was archived. Our method has unique advantages such as avoiding laborious pretreatments that adversely affect cell viability and specific delivery of transgenes into a desired cell in complex leaf tissue. This technique is a potential tool for cell specific transient gene expression studies for elucidation of gene regulation and expression.     

Survey of pesticide residues in rice (April, 1995-March, 2005)

Pesictide residues in 343 samples of domestic rice and 32 samples of imported rice purchased on the Tokyo market from April 1995 to March 2005 were investigated. Residues of eleven kinds of pesticides (including organophosphorus, organochlorine, carbamate, pyrethroid and organonitrogen pesticides and bromide) were detected at levels between trace and 1 ppm in 47 domestic rice samples. DDVP and bromide residues were detected at levels between 0.01 ppm and 5 ppm in 18 imported rice samples. For rice samples that were found to containing pesticides, the amounts of pesticide intake were calculated according to the daily intake of rice, and they were compared with the ADI values. Since residual pesticide levels were 17/10,000-2/5 of ADI, all the rice samples were considered to be safe for human consumption.     

Optimization of process and device characteristics for MOSFETs by using the BFGS method

This paper proposes an improved process/device optimization technique, which effectively determines the optimum process conditions for realizing the desired MOSFET performance. The BFGS method, which is the best quasi-Newton method now available, is introduced to save computational time. Furthermore, upper and lower boundaries are also implemented to facilitate the search for more realistic solutions.In order to demonstrate the practicality of the present simulator, channel doping conditions, such as implanted boron dose and annealing temperature, were optimized. Optimization within constraint boundaries was successfully carried out using the relationship between measured drain current and drain voltage characteristics. Consequently, it was verified that the optimization works well for a wide range of initial values and that CPU time is less dependent upon the initial values than that was obtained by using the previous method. Owing to optimization improvements, the computational time has been significantly reduced. Therefore, the present simulator is expected to become an important tool for device design.     

A virtual environment approach for planning implant placement

This paper presents details of studies on tailor-made design and production of guide templates for osseointegrated implants, which is in progress as a joint research between the Department of Mechanical Engineering and the School of Dentistry at the University of Tokushima. A guide template is used to support the accurate operation to insert implant fixtures into the appropriate site in terms of position and direction as designed before a surgical operation.The procedure in the project includes several basic steps: digital bone modelling based on medical data, planning of implant placement, designing of guide templates to support the operation, implant simulation based on the model, evaluation of the physical model using rapid prototype techniques and the production of guide templates based on the design.This paper focuses on the design issue of implant placement planning in a virtual environment to perform a tailor-made implant treatment. The placement should be designed based on the consideration of where, in which direction, and how deep the fixture should be inserted. This study uses a virtual environment, where a designer can feel the geometry of the bone, along with bone density data to enable an appropriate plan of the implant placement to be made in an intuitive manner. For surgical operation, the tailor-made guide template is used to perform an accurate operation.The paper also describes some of the basic issues regarding the design and production of a tailor-made guide template. The project is not pursuing the technology of standardized template production, but the technology of tailor-made design and production of templates with a goal towards tailor-made implant treatment which satisfies each patient based on individual needs.     

Prader-Willi syndrome with elevated follicle stimulating hormone levels and diabetes mellitus

A 21 -year-old man with Prader-Willi syndrome (PWS) was hospitalized due to hyperglycemia. After diet therapy and transient insulin administration, his blood glucose levels improved. Based on the fact that his urinary C-peptide levels increased, the diabetes mellitus may have been due to insulin resistance with obesity. In addition, his testes had become atrophied. Testosterone levels remained low even after human chorionic gonadotropin (HCG) administration. Luteinizing hormone (LH) levels were also low after LH releasing hormone (LHRH) administration. The LH response increased slightly after daily LHRH administration, indicating hypothalamic hypogonadism. Follicle stimulating hormone (FSH) levels were, however, high and increased after LHRH administration. The selective FSH elevation may have been due to the accompanying idiopathic oligospermia.     

Monte Carlo studies of the effect of emitter junction grading onthe electron transport in InAlAs/InGaAs heterojunction bipolartransistors

InAlAs/InGaAs HBTs with various emitter junction gradings are simulated using a self-consistent Monte Carlo simulator. The effects of the emitter junction grading and the shift of the emitter-base p-n junction into the emitter depletion region due to diffusion of the base dopant are investigated. A minimum transit time of 1.18 ps is predicted for an In(Ga_1-xAl_x)As grading with x=0.6 at the E-B interface and J_C=0.7×10⁵ A/cm². Graded-base designs do not offer any transit time performance improvement compared with the graded E-B approach. For transient performance, the device switching time is found to remain constant at about 2.2 ps up to x₀~0.7 but increases for larger values. A cutoff frequency as high as 270 GHz was observed for x₀=0.7, indicating that the best transport can be achieved from intermediately graded rather than abrupt E-B junction designs     

Facial identification system based on a high‐speed matching algorithm for isodensity lines

In this paper, a high‐speed personal identification system which is adaptable for slant faces is presented. In the proposed method, the 25 facial images which are taken with different angles are registered in the database as reference images. The similarity of an input image is first examined between all registered images and the three facial images, which are similar to the input image, are then extracted as the candidate facial images. The isodensity map, which is expected to have the maximum similarity to the input image, is created by the interpolation between two candidate images and the input facial image is judged identical or not with the interpolated images. A template matching is adopted to obtain a similarity between two isodensity lines. In general, template matching requires a lot of time to obtain maximum similarity, while on the other hand it is very simple to use. To reduce the processing time for the matching efficiently, the techniques which are suited for the line pictures and the Sequential Similarity Detection Algorithm (SSDA) are adopted. Computer simulation using 50 people shows an accuracy of 95.2% correct discrimination. In addition, processing time is reduced to approximately 1/12. From the experimental results, the prospects of using this method are very encouraging. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 143(4): 31–41, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10147