Performance analysis of variable optical delay circuit using highly nonlinear fiber parametric wavelength converters

The performance of a variable optical delay circuit that employs a fiber loop with highly nonlinear fiber parametric wavelength converters is discussed using both experiments and simulations. In our optical delay circuit, the delay time is determined from the number of circulations, which is controlled by the initially selected wavelength of the optical signal. We discuss the factors that limit the number of circulations described in our previous paper, derive the parameters that provide good performance levels, and confirm the performance by simulation. The simulated results indicate that 100 wavelength conversions can be achieved, namely, 100 different delay times can be given to optical packets.     

Ligand specificity of LOX-1, a novel endothelial receptor for oxidized low density lipoprotein

Endothelial dysfunction, or activation, elicited by oxidized low density lipoprotein (Ox-LDL) and its lipid constituents has been shown to play a key role in the pathogenesis of atherosclerosis. We recently have identified a novel receptor for Ox-LDL-designated lectin-like Ox-LDL receptor (LOX-1) in vascular endothelial cells. To examine ligand specificity of LOX-1, we established CHO cell lines stably expressing both human and bovine LOX-1 (LOX-1-CHO). LOX-1-CHO bound and degraded 125I-labeled Ox-LDL but did not significantly degrade 125I-labeled acetylated LDL (Ac-LDL). Fucoidin and maleylated BSA (M-BSA), which inhibit 125I-Ox-LDL binding to class A scavenger receptors, did not inhibit 125I-Ox-LDL binding or degradation in LOX-1-CHO. Polyinosinic acid and carrageenan, in contrast, significantly reduced 125I-Ox-LDL binding to LOX-1-CHO by 62% and 60%, respectively. Delipidated and untreated 125I-Ox-LDL were bound and degraded equally in LOX-1-CHO; furthermore, excess amounts of unlabeled, delipidated Ox-LDL inhibited binding and degradation of untreated 125I-Ox-LDL. Taken together, LOX-1 is a receptor for Ox-LDL but not for Ac-LDL. LOX-1 recognizes protein moiety of Ox-LDL, and its ligand specificity is distinct from other receptors for Ox-LDL, including class A and B scavenger receptors.     

Suppression by carotenoids of microtenoids of microcystin-induced morphological changes in mouse hepatocytes

Microcystin-LR is a liver tumor promoter in the okadaic acid class, a group of potent inhibitors of protein phosphatases 1 and 2A. Because of inhibition of protein phosphatases, microcystin-LR induces hyperphosphorylation of cellular proteins, including cytoskeletal proteins—cytokeratins 8 and 18—and causes morphological changes in mouse hepatocytes in primary culture. We studied the effects of carotenoids to antagonize microcystin-LR-induced morphological changes in hepatocytes. β-Carotene (100 nM to 100 μM), suppressed the morphological changes induced by 100 nM microcystin-LR in a dose-dependent manner. Other carotenoids tested exerted similar suppressive effects, although retinoids, such as all-trans retinol, all-trans retinoic acid, and 9-cis retinoic acid, were only weakly suppressive. The relative potency of the suppression correlated significantly with the number of conjugated double bonds in thetrans configuration. β-Carotene strongly suppressed the hyperphosphorylation of cellular proteins induced by microcystin-LR without significant changes in the basal phosphorylation level. Other antioxidants, such as α-tocopherol, did not protect the cells against microcystin-LR. Taken together, the antagonistic effects of carotenoids against microcystin-LR are difficult to explain by their antioxidant or provitamin A activities. Suppression of the hyperphosphorylation of cellular proteins may be a novel mechanism by which carotenoids inhibit tumor promotion.     

Cytotoxicity induced by Erythrina variegata serine proteinase inhibitors in tumor hematopoietic stem cell lines

A prospective study of activated protein C sensitivity, protein C, protein S, and other coagulation factors in 239 women during normal pregnancy was carried out. Protein C activity appeared unaffected by gestation, although an elevation of protein C activity was observed in the early puerperium. A fall in total and free protein S with increasing gestation was observed. Activated protein C sensitivity ratio (APC:SR) showed a progressive fall through pregnancy. This fall correlated with changes in factor VIIIc, factor Vc and protein S. 38% of subjects, with no evidence of Factor V Leiden or anticardiolipin antibodies, showed a low APC:SR (APC:SR <2.6) in the third trimester of pregnancy. Aside from a significant reduction in birth weight, no difference in pregnancy outcome was observed between these subjects and those with a normal APC:SR. Activated protein C sensitivity ratio, modified by pre-dilution of patient samples with factor V depleted plasma, showed no consistent trend with gestation.     

Gout and atherosclerosis

Recently atherosclerotic diseases, such as coronary heart disease and cerebrovascular disease have been considered as an important complication of hyperuricemia and gout. However, it is still controversial whether or not hyperuricemia is an independent risk factor of atherosclerotic diseases. On the other hand, several risk factors for coronary heart disease, for example hyperlipidemia and hypertension, are frequently observed in the patients with gout. Atherosclerosis in relation to hyperuricemia was discussed in view of definite and probable risk factors.     

Acyl-coenzyme A: cholesterol- acyl-coenzyme A:1,2-diacylglycerol acyltransferase and phosphatidate phosphorylase activities in liver microsomes from nephrotic rats

The optical properties of sunglasses common on the market were tested for UV radiation and visible light. Out of a large variety of sunglasses offered to customers, four types of sunglasses visually diversified, so they could suit mostly different tastes and requirements of customers, had been selected randomly. It was found that even not branded sunglasses satisfy the requirements of protective glasses. None of the sunglasses tested transmitted UV-B radiation (280-315 nm) and considerably limited UV-A radiation (315-400 nm). Moreover, radiation permeability in the visible range was good. UV-A transmission occurred mostly in the wavelength range above 380 nm. In order to evaluate the properties of protective sunglasses the ocular sun protective factor (OSPF) was defined and proposed.     

Polymers of α-substituted benzyl methacrylates as a new type of electron-beam resist

Summary Polymer of α-substituted benzyl methacrylate was found to be used as a new type of positive electron-beam resist, which forms methacrylic acid units in the polymer chain on the exposure to electron-beam and can be developed using alkaline solution as a developer. The sensitivity was dependent on the bulkiness of the ester group and the number of ?-hydrogen atoms in the ester group. The sensitivity and γ-value of atactic poly(α, α-dimethylbenzyl methacrylate) were improved by a factor of more than three over poly (methyl methacrylate).     

Digital copy milling—autonomous milling process control without an NC program

Conventional NC machine tools do not generally allow the change of cutting conditions such as depth of cut and stepover during machining operations, once they are given machining commands as NC programs. For that reason, the NC programs must be prepared adequately and verified in advance, which requires extensive time and effort. It is therefore necessary to develop functions to generate the cutter path autonomously and control the cutting conditions adaptively during machining to optimize the cutting process, maintain stable cutting, and avoid cutting trouble. This paper proposes a new architecture to realize autonomous control of the cutting process without using NC programs. A technique called digital copy milling is developed to control the NC machine tool in real time. The digital copy milling system can generate tool paths in real time, based on the principle of copy milling. In addition, a new control strategy is developed to control the cutting conditions adaptively. A prototype of an autonomous controller was implemented in a three-axis control machining center. Thereafter, experimental milling tests were carried out to verify the effectiveness of the proposed system. The cutter paths were generated autonomously by the digital copy milling system. Results show that the cutting depth and stepover can be changed during milling tests. Cutting conditions were controlled adaptively.     

Genetic regulation of the expression of H-2-K.5 antigen of erythroid cells by H-2K end

Difference in the amounts of H-2K.5 antigens present on erythrocytes was observed, using quantitative absorption method, among several B 10 congenic strains. However, no such variation was seen on the lymphocytes and lung cells. The variability in the amount of this antigen on the erythrocyte surface was primarily dependent on the haplotype of the H-2K end in the B 10 recombinant strains examined. This suggests that the regulator of H-2 expression on erythrocytes is in this region. Further genetic analysis confirmed that this regulation functions in the cis-position. Finally, the H-2K.5 antigenic activity was expressed on the reticulocytes of all strains tested, but appeared lower in the type 2 group indicating that the regulation begins early in erythropoietic differentiation and eventually results in a complete loss of detectable activity.