Collagen and elastin synthesis by desmoid tumor in vitro

In order to characterize human desmoid tumors in vitro, the production of collagen and elastin and the expression of collagen types alpha1(I), alpha1(III) and transforming growth factor (TGF)-beta1 mRNA were investigated in six desmoid tumors; five derived from familial adenomatous polyposis patients and one from a sporadic case. The proportion of collagen production to total protein production was determined by 3H-imino acid incorporation, an indicator of collagen synthesis, using high-performance liquid chromatography (HPLC). The proportion of collagen production to total protein production was much higher in all six desmoid tumors compared with human skin fibroblasts (HSF). Quantitatively, the rate of elastin synthesis in desmoid tumor cells monitored by valine-proline peptide was also significantly higher than in HSF. Pro-alpha1(I) collagen mRNA was highly expressed in both desmoid tumors and HSF at approximately the same level, whereas pro-alpha1(III) collagen mRNA was more abundant in some of the desmoid tumors than the normal skin fibroblastic cell lines. Tumor growth factor-beta1 mRNA, which is believed to stimulate collagen synthesis, was expressed in both desmoid tumors and HSF to the same extent. These results demonstrate the increased formation of collagen and elastin in desmoid tumors in vitro and suggest that the increased synthesis of elastin rather than of collagen and TGF-beta1 may be involved in increased fibrogenesis by desmoid tumors.     

Integration of GaAs m.e.s.f.e.t.s and Gunn elements in a 4 bit-gate device

A GaAs m.e.s.f.e.t. and a Schottky electrode-triggered Gunn element have been integrated into a single device which operated as a negative logic inhibitor. A monolithic device of four such inhibitors, connected in cascade, was operated in a stable manner, with a signal delay per gate as small as 40 ps.     

Magnetic field detection for current evaluation by magnetic force microscopy

A current measurement method through magnetic field detection by magnetic force microscopy was proposed and demonstrated. We observed the magnetic field induced by an AC below 2.2 μA around a GaAs/AlGaAs mesa stripe. To achieve high sensitivity in magnetic field detection, we tuned the AC bias frequency to the torsional resonant frequency of the cantilever. As a result, the sensitivity of the magnetic field detection was much improved and specific features of the magnetic field around the mesa stripe were clearly observed at a current in sub-μA range.     

Analytical electron microscopy and electron holography on microstructures and magnetic domain structures of Sm-Co 2:17 magnets

Microstructures and magnetic domain structures of precipitation-hardened Sm-Co permanent magnets were systematically investigated by analytical electron microscopy and electron holography. By an elemental mapping method with energy-dispersive X-ray spectroscopy, the change in the local distribution of additive elements, i.e. Cu, Fe and Zr, in Sm-Co magnets with various heat treatments was visualized and the enrichment of Zr in the Z-phase with a width of approximately 1 nm was clarified directly. Detailed analysis with electron holography revealed that considerable fluctuation in the distribution of lines of magnetic flux in the step-aged magnet was due to the chemical partitioning of additives and resulted in magnetic hardening during the magnetization process.     

Composite of Au nanoparticles and molecularly imprinted polymer as a sensing material

A molecularly imprinted polymer with immobilized Au nanoparticles (Au-MIP) is reported as a novel type of sensing material. The sensing mechanism is based upon the variable proximity of the Au nanoparticles immobilized in the imprinted polymer, which exhibits selective binding of a given analyte accompanied by swelling that causes a blue-shift in the plasmon absorption band of the immobilized Au nanoparticles. Using adrenaline as the model analyte, it was shown that molecular imprinting effectively enhanced the sensitivity and selectivity, and accordingly, Au-MIP selectively detects the analyte at 5 microM. The combination of molecular imprinting and the Au nanoparticle-based sensing system was shown to be a general strategy for constructing sensing materials in a tailor-made fashion due to wide applicability of the imprinting technique and the independence of the sensing mechanism from the analyte recognition system.     

Simple and comprehensive two-dimensional reversed-phase HPLC using monolithic silica columns

Simple and comprehensive two-dimensional (2D)-HPLC was studied in a reversed-phase mode using monolithic silica columns for second-dimension (2nd-D) separation. Every fraction from the first column, 15 cm long (4.6-mm i.d.), packed with fluoroalkylsilyl-bonded (FR) silica particles, was subjected to the separation in the 2nd-D using one or two octadecylsilylated (C(18)) monolithic silica columns (4.6-mm i.d., 3 cm). Monolithic silica columns in the 2nd-D were eluted at a flow rate of up to 10 mL/min with separation time of 30 s that meets the fractionation every 15-30 s at the first dimension (1st-D) operated at a flow rate of 0.4-0.8 mL/min. Three cases were studied. (1) In the simplest scheme of 2D-HPLC, effluent of the 1st-D was directly loaded into an injector loop of 2nd-D HPLC for 28 s, and 2 s was allowed for injection. (2) Two six-port valves each having a sample loop were used to hold the effluent of the 1st-D alternately for 30 s for one 2nd-D column to effect comprehensive 2D-HPLC without the loss of 1st-D effluent. (3) Two monolithic silica columns were used for 2nd-D by using a switching valve and two sets of 2nd-D chromatographs separating each fraction of the 1st-D effluent with the two 2nd-D columns alternately. In this case, two columns of the same stationary phase (C(18)) or different phases, C(18) and (pentabromobenzyloxy)propylsilyl-bonded (PBB), could be employed at the 2nd-D, although the latter needed two complementary runs. The systems produced peak capacity of approximately 1000 in approximately 60 min in cases 1 and 2 and in approximately 30 min in case 3. The three stationary phases, FR, C(18), and PBB, showed widely different selectivity from each other, making 2D separations possible. The simple and comprehensive 2D-HPLC utilizes the stability and high efficiency at high linear velocities of monolithic silica columns.     

Reconstruction of a high-resolution image on a compound-eye image-capturing system

The authors have proposed an architecture for a compact image-capturing system called TOMBO (thin observation module by bound optics), which uses compound-eye imaging for a compact hardware configuration [Appl. Opt. 40, 1806 (2001)]. The captured compound image is decomposed into a set of unit images, then the pixels in the unit images are processed with digital processing to retrieve the target image. A new method for high-resolution image reconstruction, called a pixel rearrange method, is proposed. The relation between the target object and the captured signals is estimated and utilized to rearrange the original pixel information. Experimental results show the effectiveness of the proposed method. In the experimental TOMBO system, the resolution obtained is four times higher than that of the unit image that did not undergo reconstruction processing.     

Transferred-electron negative-resistance amplifier

It has experimentally been shown that the travelling domain oscillations in an n type GaAs bulk element can be suppressed by applying externally a large microwave-signal electric field. A computer calculation indicates a possibility of amplifying the signal when the element mounted in a stripline is subject to such a relatively large microwave signal.     

Occurrence,horizontal transfer and degeneration of VDE intein family in Saccharomycete yeasts

VDE is a homing endonuclease gene originally discovered as an intervening element in VMA1s of Saccharomyces cerevisiae. There have been two independent subfamilies of VDE, one from S. cerevisiae strain X2180-1A and the other from Saccharomyces sp. DH1-1A in the host VMA1 gene, and they share the identity of 96.3%. In order to search the occurrence, intra/interspecies transfer and molecular degeneration of VDE, complete sequences of VMA1 in 10 strains of S. cerevisiae, eight species of saccharomycete yeasts, Candida glabrata and Kluyveromyces lactis were determined. We found that six of 10 S. cerevisiae strains contain VDEs 99.7-100% identical to that of the strain X2180-1A, one has no VDE, whereas the other three harbour VDEs 100% identical to that of the strain DH1-1A. S. carlsbergensis has two VMA1s, one being 99.8% identical to that of the strain X2180-1A with VDE 100% identical to that of the strain DH1-1A and the other containing the same VMA1 in S. pastorianus with no VDE. This and other evidence indicates that intra/interspecies transmissions of VDEs have occurred among saccharomycete yeasts. Phylogenetic analyses of VMA1 and VDE suggest that the S. cerevisiae VDEs had branched earlier than other VDEs from an ancestral VDE and had invaded into the host loci as relatively late events. The two VDEs seemed to degenerate in individual host loci, retaining their splicing capacity intact. The degeneration of the endonuclease domains was distinct and, if compared, its apparent rate was much faster than that of the protein-splicing domains.     

乙酸丁酯反应精馏过程模拟设计

反应精馏偶合了反应和精馏两种单元操作,通过精馏促进反应,可以提高反应转化率和收率,为可逆反应的化工过程生产提供了新的设计途径。基于严格热力学分析计算,利用计算机模拟和优化手段。提出了乙酸丁酯反应精馏、分离纯化的生产流程。采用UNIQUAC方程表征乙酸-正丁醇-乙酸丁酯-水四元非理想体系的汽液平衡,首先,根据实验数据回归了热力学模型中的交互作用参数,并预测了体系中5个共沸物组成,模型的计算结果与实际数据吻合。基于平衡级模型,提出了由平衡反应器、反应精馏塔、倾析器和纯化塔构成的可行流程,对提出的设计流程进行了模拟、优化,得到了操作工艺参数。模拟结果对工业过程的设计和改造具有一定的指导意义。