Novel alignment mechanism of liquid crystal on a hydrogenated amorphous silicon oxide

The mechanism of liquid crystal (LC) alignment has been investigated during the last few decades for inorganic materials as well as for organic materials; however, it has not been clearly confirmed for some alignment materials. Inorganic alignment materials such as amorphous silicon oxide (a-SiOx) and hydrogenated amorphous silicon oxide (a-SiOx:H) are deposited on indium tin oxide (ITO) films on glass by reactive sputtering deposition. After deposition, the inorganic alignment materials are irradiated using an Ar+ ion beam (IB) for LC alignment. On the basis of the experimental results, a-SiOx films deposited by the sputtering do not align the LC, but a-SiOx:H films treated with varying IB energies, IB incident angles, IB doses, and IB irradiation times have excellent alignment properties and electrooptical properties, identical to those of polyimide (PI). These results imply that inorganic alignment layers irradiated by IB can be adopted as an LC alignment layer instead of rubbed PI. Additionally, hydrogen plays an important role in LC alignment because of the difference in alignment properties between a-SiOx films and a-SiOx:H films. We investigate the mechanism of IB-treated inorganic alignment layers and suggest that LCs are aligned by chemical effects, such as van der Waals interaction, more than by physical effects, such as morphology effects, in the inorganic alignment layer irradiated by IB.

Effects of activation of polymorphonuclear leukocytes on airway goblet cell mucin release in a co-culture system

OBJECTIVE AND DESIGN

Effects of activated PMN on airway goblet cell mucin release were investigated using a co-culture system in which both tracheal surface epithelial (TSE) cells and PMN from hamsters were present.

MATERIALS AND METHODS

TSE cells were metabolically labeled using (3)H-glucosamine and chased in the presence of PMN under various experimental designs. PMN were obtained from the bronchoalveolar lavage fluid of hamsters following intratracheal instillation of E. coli endotoxin. The amount of (3)H-mucin was measured by Sepharose CL-4B gel-filtration column chromatography.

RESULTS

(i). activation of 10(6) PMN by fMLP (0.1 microM) and cytochalasin B (0.1 microM) resulted in production of both the estrolytic ("elastolytic") activity and superoxide, (ii). activation of PMN in the co-culture stimulated mucin release from TSE cells followed by a significant degradation of the released mucins, both of which were blocked in a dose-dependent fashion by pretreatment with alpha1-protease inhibitor, and (iii). generation of varying concentrations of superoxide in the TSE cell culture did not affect mucin release from TSE cells.

CONCLUSION

In the co-culture system, activation of PMN results in release and degradation of mucins, both of which are almost entirely accounted for by serine proteases but not other cellular products such as superoxide.

Imatinib (ST1571) provides only limited selectivity for CML cells and treatment might be complicated by silent BCR-ABL genes

Very promising results have been obtained in clinical trials on chronic-phase chronic myeloid leukemia (CP-CML) patients treated with imatinib mesylate (IM; Gleevecr, STI571), a BCR-ABL tyrosine kinase inhibitor. However, we found that IM caused considerable inhibition of normal hematopoietic progenitor cells upon treating control bone marrow (BM) cultures. In vitro IM treatment gave a decrease in the yield and size of colonies from BM of untreated CP-CML patients that was only two to three times that from the normal samples. Moreover, about 30% of myeloid progenitors (CFU-GM) from CML BM still formed colonies in the presence of IM, most of which had BCR-ABL RNA. About half of these treated colonies also displayed methylation of the internal ABL Pa promoter, a CML-specific epigenetic alteration, which was used in this study as a marker for BCR-ABL translocation-containing cells. However, ~5-8% of the treated or the untreated CML BM-derived colonies had no detectable BCR-ABL RNA by two or three rounds of RT-PCR despite being positive for the internal standard RNA and displaying hallmarks of CML, either t(9;22)(q34;ql 1) or ABL Pa methylation. Our results indicate that IM is only partially specific for CML progenitor cells compared to normal hematopoietic progenitor cells and suggest that some CML cells may have a silent BCR-ABL oncogene that could interfere with therapy.

Intra-group differences in business participation: three Asian immigrant groups

This study investigates ethnic and nativity differentials in self-employment based on the small-business experiences of 3 Asian immigrant groups in the US: Korean, Chinese, and Asian Indians. In light of the 1980 Census data, the intra- and the inter-group differences in the business participation rates of these Asian immigrant groups are examined. Findings reveal that each group has substantial intra-group differences in the business participation rate, and the differences can best be explained by the interactive approach proposed by this study. Moreover, a comparative study (inter-group comparison) of these intra-group differences opens a new avenue to understanding the various patterns of business participation among recent immigrants from Asia.

Effects of polycationic peptides on mucin release from airway goblet cells: relationship between polymer size and activity

OBJECTIVES AND DESIGN

Various sizes of poly-L-lysine (PLL) and poly-L-arginine (PLA) were tested for their possible effects on airway goblet cell mucin release using primary hamster tracheal surface epithelial (HTSE) cells in an attempt to identify the smallest size of the polycationic peptide to suppress mucin release without cytotoxicity.

MATERIALS AND METHODS

HTSE cells were metabolically labeled using 3H-glucosamine and chased in the presence of varying concentrations of various sizes of the polycationic peptides. The amount of 3H-mucin in the spent media was measured by Sepharose CL-4B gel-filtration column chromatography. Possible cytotoxicity of the peptides was assessed by measuring the release of lactic dehydrogenase (LDH) during the treatment period.

RESULTS

(1) PLL (MW 78,000) inhibited whereas PLA (MW 92,000) stimulated mucin release. However, these peptides were cytotoxic at the effective concentrations; (2) Both PLL (MW 9,600) and PLA (MW 8,900) could inhibit mucin release in a dose dependent manner without cytotoxicity; (3) Both PLL and PLA were effective in suppressing mucin release in 20-mer but not in either 10-mer or 5-mer; (4) 14-mers of both PLL and PLA also inhibited mucin release without cytotoxicity; (5) PLL and poly-D-lysine (PDL) of 14-mer were equipotent in its ability to suppress mucin release.

CONCLUSION

Both PLL and PLA are cytotoxic at 'high' molecular weights, but have an ability to suppress mucin release without cytotoxicity at 'low' molecular weights. 14-mer seems to be the small, effective size, if not the smallest, for both PLL and PLA to suppress mucin release without cytotoxicity. The inhibitory effect of these polycationic peptides seems to be determined by the presence and the absolute number of positive charges and also to be independent of optical isomerism.