A two-layered approach to communicative artifacts

A key issue in social intelligence design is the realization of artifacts that can fluently communicate with people. Thus, we proposed a two-layered approach to enhance a robot’s capacity of involvement and engagement. The upper layer flexibly controls social interaction by dynamic Bayesian networks (DBN) representing social interaction patterns. The lower layer improves the robustness of the system by detecting rhythmic and repetitive gestures. We designed a listener robot that can follow and record humans’ explanation on how to assemble and/or disassemble a bicycle. The implementation of this system is described by assembling the key algorithms presented in this paper.     

A case of food-dependent exercise-induced anaphylaxis induced by shrimp

The clinical study and in vitro study used with leukocytes were made of a case of food-dependent exercise-induced anaphylaxis induced by shrimp. A 26-year-old man experienced anaphylactic reaction of nasal obstruction, face edema and dyspnea while running 90 minutes after eating shrimp. He experienced similar episodes two years ago in his past history. IgE-RAST was positive for shrimp. Anaphylactic reaction and elevation of plasma histamine levels were verified by exercise challenge test after eating 100 g shrimp. At the same time, we verified the dedine of plasma cAMP levels after eating shrimp. In leukocyte stimulating test used with shrimp antigen, histamine level elevations, which were lower compared with calcium ionophore A23187 (Ca I 10(-6) M) stimulation, were recognized in dose dependent manner in this patient. But in normal subject, histamine level elevations were not recognized. We diagnosed him food-dependent exercise-induced anaphylaxis. It was suggested that there was relation between histamine release and decline of cAMP levels of plasma after eating shrimp in this case.     

Control of optical anisotropy of cellulose esters and their blends with plasticizer

Orientation birefringence of various cellulose esters, such as cellulose triacetate, cellulose acetate propionate and cellulose acetate butyrate, and their blends with a plasticizer are studied. It is found that propionyl and butyryl groups show positive orientation birefringence, whereas the acetyl group exhibits negative birefringence. These results indicate that a cellulose ester with an appropriate composition of ester groups shows no orientation birefringence, irrespective of the molecular orientation. Further, photoelastic birefringence of cellulose esters in the glassy state is also investigated, and is found to be more pronounced with increasing butyryl group content. Moreover, the addition of the plasticizer affects both the orientation and photoelastic birefringences. It should be noted that the magnitude of these birefringences is dependent on the plasticizer species. Plasticizers with a large solubility parameter enhance the birefringence, whereas those with a small solubility parameter decrease it. Moreover, infrared dichroic measurements suggest that the orientation birefringence is mainly determined by the polarizability anisotropy of the ester groups, which is affected by the plasticizer.     

N-alkylated nitrogen-in-the-ring sugars: conformational basis of inhibition of glycosidases and HIV-1 replication

The conformations of nitrogen-in-the-ring sugars and their N-alkyl derivatives were studied from 1H NMR analyses, mainly using 3J(H,H) coupling constants and quantitative NOE experiments. No significant difference was seen in the ring conformation of 1-deoxynojirimycin (1), N-methyl-1-deoxynojirimycin (2), and N-butyl-1-deoxynojirimycin (3). However, it was shown that the C6 OH group in 1 is predominantly equatorial to the piperidine ring, while that in 2 or 3 is predominantly axial, and its N-alkyl group is oriented equatorially. In the furanose analogues 1,4-dideoxy-1,4-imino-D-arabinitol (4) and its N-methyl (5) and N-butyl (6) derivatives, the five-membered ring conformation differed significantly by the presence or absence of the N-substituted group and the length of the N-alkyl chain. Compound 3 reduced its inhibitory effect on almost all glycosidases, resulting in an extremely specific inhibitor for processing alpha-glucosidase I since N-alkylation of 1 is known to enhance both the potency and specificity of this enzyme in vitro and in vivo. This preferred (C6 OH axial) conformation in 2 and 3 appears to be responsible for their strong alpha-glucosidase I activity. Compound 4 is a good inhibitor of intestinal alpha-glucohydrolases, alpha-glucosidase II, and Golgi alpha-mannosidases I and II, but its N-alkyl derivatives 5 and 6 markedly decreased inhibitory potential for all enzymes tested. In the case of 2,5-dideoxy-2,5-imino-D-mannitol (DMDP, 7), which is a potent beta-galactosidase inhibitor, its N-methyl (8) and N-butyl (9) derivatives completely lost potency toward beta-galactosidase as well. N-Alkylation of compounds 4 and 7, known well as potent yeast alpha-glucosidase inhibitors, resulted in a serious loss of inhibitory activity toward yeast alpha-glucohydrolases. Activity of these nine analogues against HIV-1 replication was determined, based on the inhibition of virus-induced cytopathogenicity in MT-4 and MOLT-4 cells. Compounds 2 and 3, which are better inhibitors of alpha-glucosidase I than 1, proved active with EC50 values of 69 and 49 micrograms/mL in MT-4 cells and 100 and 37 micrograms/mL in MOLT-4 cells, respectively, while none of the furanose analogues exhibited any inhibitory effects on HIV-1. The change in potency and specificity of bioactivity by N-alkylation of nitrogen-in-the-ring sugars appears to be correlated with their conformational change.     

XAFS study of europium chloride at high temperatures

Local structural changes in europium dichloride around europium ion at high temperature are evaluated by using X-ray absorption fine structure technique. A distinct phase shift in EXAFS oscillation observed between 700 and 950K arises from Eu²⁺ to Eu³⁺ oxidation. Referring to the difference in EXAFS oscillation between oxide and oxychloride of lanthanum, the chemical state of europium on oxidation is identified mainly as Eu₂O₃.