A novel, cellulolytic, bacterial thermophilic strain, T4, was isolated from sugar refinery wastewater in southern Taiwan. This isolate, a Gram-negative, motile, aerobically growing sporulating rod, can secrete thermostable endocellulase (endo-1,4-beta-D-glucanase, EC 3.2.1.4) and hydrolyze carboxymethylcellulose (CMC), phosphoric acid-swollen cellulose, Avicel, filter paper, and salicin. When strain T4 was grown in CMC medium, the cellulolytic enzyme activity in culture supernatants was stable up to 70 degrees C. More than 10% of the original activity was still detectable after heating to 100 degrees C with a pH 7.0 for 1 h. Based on 16S rDNA sequence analysis, DNA base composition, phenotypic and physiological characteristics, as well as DNA-DNA hybridization, strain T4 was classified as Geobacillus thermoleovorans T4 (DSM 14791 = CCRC 17200). We also demonstrated that the type species G. stearothermophilus (DSM 22 = ATCC 12980) could hydrolyze amorphous and crystalline (filter paper) celluloses at a rate of 13 and 14%, respectively, in comparison with strain T4.

An exact analytical study is presented for the electrophoresis of an infinite insulating cylinder in the proximity of an infinite plane wall parallel to its axis. The electric field is exerted perpendicular to the particle axis in two fundamental cases: normal to a conducting plane and parallel to a non-conducting wall. The electrical double layers adjacent to solid surfaces are assumed to be thin with respect to the particle radius and the gap thickness between surfaces. The two-dimensional electrostatic and hydrodynamic governing equations are solved in the quasi-steady limit using bipolar coordinates and the typical electric-field-line, equipotential-line and streamline patterns are exhibited. Corrections to Smoluchowski's equation for the electrophoretic velocities of the particle are determined in simple closed forms as a function of λ, the ratio of particle radius to distance of the particle axis from the wall. Interestingly, the electrophoretic mobility of the cylinder in the direction parallel to a dielectric plane increases monotonically as the particle approaches the wall and becomes infinity when the particle touches the wall. For the motion of a cylinder normal to a conducting plane, the presence of the wall causes a reduction in the electrophoretic velocity, which goes to zero as λ → 1. It is found that boundary effects on the electrophoresis of a cylinder are much stronger than for a sphere at the same value of λ. The boundary effects on the particle mobility and on the fluid flow pattern in electrophoresis differ significantly from those of the corresponding sedimentation problem with which comparisons are made.

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This paper reports a new polymeric, aspheric SU-8 microlens array using a soft replica molding method and its application to cell counting. A bio-detection system comprising the SU-8 microlens array with its three-dimensional convex geometry, a micro flow cytometer chip and an optical detection module is demonstrated. A polymethyl methacrylate (PMMA) template is first fabricated and then the SU-8 microlens array is replicated using a new fabrication process. The developed array has four sizes of microlens, with diameters of 50, 100, 150 and 200 µm. Experimental results show that the surface roughness of the microlens was only 10.2 nm for the SU-8 polymer material. The microlens had good surface uniformity and excellent optical properties with calculated focal lengths ranging from tens to hundreds of micrometers, depending on their dimensions. A microlens with a high numerical aperture ranging from 0.3 to 0.75 was achieved. The microlens array can be used to increase the efficiency of the optical detection, allowing high-resolution detection and providing a high signal-to-noise ratio. The microlens array has the potential to be widely used for optical or biophotonic applications and for the integration of microfluidic devices. In order to demonstrate its capability, the developed microlens array was integrated with a micro flow cytometer for cell counting applications. Successful counting of fluorescent-labeled human lung cancer cells is demonstrated using the developed method.

Maleation of a thermoplastic elastomer, styrene‐[ethylene‐butylene]‐styrene (SEBS) triblock copolymer, was carried out by a solution grafting reaction with maleic anhydride initiated by dicumyl peroxide. The reaction products from the graft reaction in xylene, commonly chosen as the solvent for maleation graft reactions, were identified using liquid chromatograph (LC), IR, and 13C‐NMR. Side products from the graft reaction were identified by the LC analysis and, it was concluded that xylene affected the graft reaction through its active methyl groups. Reaction mechanisms were investigated by performing free radical kinetics analysis. The reaction orders and the apparent rate constant were estimated. It was concluded that a proper choice of the solvent might favor better graft efficiency. © 1993 John Wiley & Sons, Inc.

Bacteria associated with eight field-collected and five cultured soft corals of Briareum sp., Sinularia sp., Sarcophyton sp., Nephtheidae sp., and Lobophytum sp. were screened for their abilities in producing antimicrobial metabolites. Field-collected coral samples were collected from Nanwan Bay in southern Taiwan. Cultured corals were collected from the cultivating tank at National Museum of Marine Biology and Aquarium. A total of 1,526 and 1,138 culturable, heterotrophic bacteria were isolated from wild and cultured corals, respectively; seawater requirement and antimicrobial activity were then assessed. There is no significant difference between the ratio of seawater-requiring bacteria on the wild and cultured corals. The ratio of antibiotic-producing bacteria within the seawater-requiring bacteria did not differ between the corals. Nineteen bacterial strains that showed high antimicrobial activity were selected for 16S rDNA sequencing. Three strains could be assigned at the family level (Rhodobacteraceae). The remaining 16 strains belong to eight genera: Marinobacterium (2 strains), Pseudoalteromonas (1), Vibrio (5), Enterovibrio (1), Tateyamaria (1), Labrenzia (2), and Pseudovibrio (4). The crude extract from bacteria strains CGH2XX was found to have high cytotoxicity against the cancer cell line HL-60 (IC(50) = 0.94 μg/ml) and CCRF-CEM (IC(50) = 1.19 μg/ml). Our results demonstrate that the marine bacteria from corals have great potential in the discovery of useful medical molecules.

Fluorinated aliphatic polyurethanes based on hexamethylene diisocyanate (HDI) and polytetramethyl oxide (PTMO) were synthesized by using 2,2,3,3,4,4,5,5‐octafluoro‐1,6‐hexanediol (OF) or 2,2,3,3‐tetrafluoro‐1,4‐ butanediol (TF) as a chain extender. The polyurethanes chainextended with 1,4‐butanediol (BD) were also prepared for comparison. The effects of the kind of chain extender and the average length of hard segments on the microstructure, thermal transition property, surface property and blood compatibility of the polyurethanes are discussed. The fluorinated polyurethanes exhibit weaker hydrogen bonding, a smaller fraction of hydrogen‐bonded carbonyls, less phase separated soft segment domains, a lower melting temperature and less heat of fusion of crystalline hard segment domains than the polyurethanes chain extended with BD. The polyurethanes extended with OF show the above mentioned effects more obviously than those with TF. The increase of the average length of hard segments also affects the properties, especially as the average length of hard segments increases from 1 to 2. The polyurethanes chain extended with OF posses more fluorocarbon chains at the surface than those chain extended with TF. The hard segment content of the surface and the fluorine/carbon atomic ratio increases as the bulk average length of hard segments increases. In vitro platelet adhesion studies indicated that the addition of fluorocarbon chains into aliphatic polyurethanes leads to a reduction in platelet adhesion and activation.