Early stage of the crystallization in amorphous Fe–Si layers: Formation and growth of metastable α-FeSi2

Crystallization processes of amorphous Fe–Si layers have been investigated using transmission electron microscopy (TEM). Si(1 1 1) substrates were irradiated with 120 keV Fe ions at ?150 °C to a fluence of 1.0 × 10¹⁷ cm². An Fe-rich amorphous layer embedded in an amorphous Si was formed in the as-irradiated sample. Plan-view TEM observations revealed that a part of the amorphous Fe–Si layer crystallized to the metastable α-FeSi₂ after thermal annealing at 350 °C for 8 h. The lattice parameter of c-axis decreased with thermal annealing. It was considered that the change in the lattice parameter originates from the decrease of the Fe occupancy at (0, 0, 1/2) and its equivalent positions in the unit cell of the metastable α-FeSi₂.     

Acceptor recognition of kojibiose phosphorylase from Thermoanaerobacter brockii: syntheses of glycosyl glycerol and myo-inositol

The glucosyl transfer reaction of kojibiose phosphorylase (KP; EC 2.4.1.230) was examined using glycerol or myo-inositol as an acceptor. In the case of glycerol, KP produced two main transfer products: saccharides A and B. The structure of saccharide A was O-alpha-D-glucopyranosyl-(1-->1)-glycerol and that of saccharide B was O-alpha-D-glucopyranosyl-(1-->2)-O-alpha-D-glucopyranosyl-(1-->1)-glycerol. These results show that KP transferred a glucose residue to the hydroxyl group at position 1 of glycerol. On the other hand, when myo-inositol was used as an acceptor, KP produced four transfer products: saccharides 1-4. The structures of saccharides 1 and 2 were O-alpha-D-glucopyranosyl-(1-->1)- and O-alpha-D-glucopyranosyl-(1-->5)-myo-inositol, respectively; those of saccharides 3 and 4 were O-alpha-D-glucopyranosyl-(1-->2)-O-alpha-D-glucopyranosyl-(1-->1)- and O-alpha-D-glucopyranosyl-(1-->2)-O-alpha-D-glucopyranosyl-(1-->5)-myo-inositol, respectively. KP transferred a glucose residue to the hydroxyl group at position 1 or 5 of myo-inositol. On the basis of the structures of their glucosyl transfer products, glycerol and myo-inositol were found to have a common structure with three hydroxyl groups corresponding to the hydroxyl group of the glucose molecule at positions 2, 3 and 4. The conformation of these three hydroxyl groups in the structure is equatorial. This structure is the substrate recognition site of KP. It has been suggested that KP strictly recognizes the structures of glycerol and myo-inositol, and catalyzes the transfer reaction of a glucose residue to the hydroxyl group at position 1 in glycerol, and at position 1 or 5 in myo-inositol, corresponding to position 2 in glucose.     

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.     

Optimal production-inventory policy for make-to-order versus make-to-stock based on the M/Er/1 queuing model

This paper analyzes a multi-product production / inventory system where demands for each item arrive according to a Poisson process and the production time for each product has an Erlang distribution. The paper proposes an optimality condition that specifies whether each product should be produced make-to-stock or make-to-order. In the event a product should be produced make-to-stock, an approach for computing the optimal base-stock level is proposed. Numerical examples are given for illustrative purpose.     

Role of peritoneal lavage smears and gastric wall brushing smears in gastric cancer surgery

Examinations of peritoneal lavage smears (LC) and gastric wall brushing smear cytology (BC) appear to be important for determining accurately the stage of gastric cancer. We have been carrying out such examinations during gastric cancer surgery for 7 years. In the present study, we evaluated the results obtained from 287 patients with gastric cancer. Tumor invasion and peritoneal dissemination were correlated with a positive incidence of cancer cells in LC and/or BC. Gastric cancer showing serosal invasion was classified into positive for LC and/or BC and negative for LC and/or BC. Patients positive for LC and/or BC had a poorer prognosis. For future gastric cancer treatment, patients positive for peritoneal cytology are expected to be targeted for intensive treatment during or before surgery.     

Mechanochemical block copolymerization in heterogeneous systems of the solid poly(vinyl chloride) with styrene by ultrasonic irradiation

Summary Mechanochemical block copolymerization in heterogeneous systems of the solid poly(vinyl chloride)-styrene-sodium dodecyl sulfate aqueous solutions has been studied by ultrasonic irradiation at 65 °C. The block copolymerization of styrene was initiated by free radicals produced from the poly(vinyl chloride) particles by ultrasonic waves. The initial rate of the block copolymerization Rp was given by Rp α [Styrene] [Sodium dodecyl sulfate]^1/2. Both copolymer and homopolymer were obtained. For example, when 2.506 g of the poly(vinyl chloride) particles, 24.23 g of styrene, and 54.00 g of sodium dodecyl sulfate aqueous solution (0.500 wt%) were added in the reaction system, the weight proportions of the block copolymer and polystyrene after 60 min were approximately 50 and 20%.     

Laser flash photolysis studies on homo-and copolymers of phenylisopropenyl ketone and of pivalophenone in solution

Benzene solutions of poly(phenylisopropenyl ketone) (PPIK), of copolymers of PIK and styrene and of phenyl-t-butyl ketone (pivalophenone) were irradiated with light flashes (duration 25 nsec) at wavelength 347 nm. The spectra observed at the end of the flash were attributed to the triplet state (T-T-spectra). A fraction of the triplets in the polymers was deactivated by T-T annihilation, as evidenced by lifetimes decreasing with increasing absorbed dose rate. Upon extrapolation to zero intensity the following triplet decay rate constants K_T were obtained:

$\text{(1.0 ± 0.1) 10}{}^7\text{sec}{}^{\mathrm{?}}\text{(}\text{PPIK}\text{),}$

$\text{(8 ± 1) 10}{}^6\text{sec}{}^{\mathrm{?1}}\text{(}\text{CPStPlK12}\text{), (6 ± 1) 10}{}^6\text{sec}{}^{\mathrm{?1}}\text{(}\text{CPStPlK3.7}\text{)}$

$\text{(3 ± 1) 10}{}^6\text{sec}{}^{\mathrm{?1}}\text{(}\text{CPStPlK1}\text{)}$

$\text{(2.5 ± 0.2) 10}{}^6\text{sec}{}^{\mathrm{?1}}\text{(}\text{pivalophenone}\text{)}$

.In PPIK and pivalophenone the dominant chemical route of triplet deactivation is α-cleavage. The relatively high k_T value found with PPIK is presumably due to next neighbour interaction. In copolymers with a high content of isolated PIK units type I processes (α-cleavage) become less probable due to weak next neighbour influence. Thus type II processes dominate in copolymers although being slower than type I processes in homo PPIK. The rate constant of the reaction of PIK triplets in homo PPIK with 2-propanol in benzene solution is (2.0 ± 0.2)10⁶ l/mol sec, whereas pivalophenone triplets react almost 10 times slower with 2-propanol. The difference is assumed to be due to a rather strong interaction of 2-propanol with ground state as well as with excited pivalophenone.     

Synthesis and application of fluorescein- and biotin-labeled molecular probes for the chemokine receptor CXCR4

The design, synthesis, and bioevaluation of fluorescence- and biotin-labeled CXCR4 antagonists are described. The modification of D-Lys8 at an epsilon-amino group in the peptide antagonist Ac-TZ14011 derived from polyphemusin II had no significant influence on the potent binding of the peptide to the CXCR4 receptor. The application of the labeled peptides in flow cytometry and confocal microscopy studies demonstrated the selectivity of their binding to the CXCR4 receptor, but not to CXCR7, which was recently reported to be another receptor for stromal cell-derived factor 1 (SDF-1)/CXCL12.