Enantioseparation of (R,S)-ketoprofen using Candida antarctica lipase B in an enzymatic membrane reactor

An enzymatic membrane reactor (EMR) for enantioseparation of (R,S)-ketoprofen via Candida antarctica lipase B (CALB) as biocatalyst was investigated. A comparative study of free and immobilized CALB was further conducted. The catalytic behaviour of CALB in an EMR was affected by the process parameters of enzyme load, substrate concentration, substrate molar ratio, lipase solution pH, reaction temperature, and substrate flow rate. Immobilization of CALB in the EMR was able to reduce the amount of enzyme required for the enantioseparation of (R,S)-ketoprofen. Immobilized CALB in the EMR assured higher reaction capacity, better thermal stability, and reusability. It was also found to be more cost effective and practical than free CALB in a batch reactor.     

Influences of Seven Taiwan‐Produced Adulterants on Gas Chromatographic‐Mass Spectrometric (GC‐MS) Urinalysis of Amphetamines

This study was conducted to better understand the influences exerted by seven Taiwan‐produced adulterants on the forensic gas chromatographic‐mass spectrometric (GC‐MS) confirmatory urinalysis of amphetamines. The results verified that, when added at 5‐15% (w/w), chlorine bleach would lower the GC‐MS outcomes of the spiked and case specimens by 36‐63%, and was most likely to cause false negatives. Liquid soap, potassium dichromate, soda water for drinking, and tap water would decrease the GC‐MS outcomes by 9‐29%, 8‐20%, 8‐20%, and 5‐16%, respectively, and also had the risk of negating near‐cutoff initial positives into false confirmatory negatives. The negative‐directing effects were mostly due to degradation of analytes and/or deactivation of the derivatizing agent by oxidizing adulterants and/or dilution of analytes by the added liquid. Alum and table salt added as powder had little impact on the test. Responsible institutions and relevant laboratories should face the facts seriously and include the specimen validity testing (SVT) battery in the routine drug testing procedures.     

Effect of Indole‐3‐Acetic Acid Analogs on the Differentiation of HL‐60 Cells

In continuing search for novel cell differentiation agents, a series of derivatives of indole‐3‐acetic acid and indole‐3‐carboxylic acid were prepared and tested against HL‐60 cells for their differentiation and antiproliferation activities. Among them, N‐ethyl‐1‐benzylindole‐3‐carboxamide ( 14 ) was the most potent, whereas N‐methyl 1‐benzylindole‐3‐acetamide ( 5 ) and N‐methyl 1‐benzylindole‐3‐carboxamide ( 13 ) synergistically potentiated with all‐trans‐retinoic acid to induce cell differentiation as well as antiproliferation. Our results indicate that these compounds are effective cell differentiation and antiproliferation agents in combination with retinoic acid.     

Use of statistical methods to find the polysaccharide structural characteristics and the relationships between monosaccharide composition ratio and macrophage stimulatory activity of regionally different strains of Lentinula edodes

Multiple linear regression analysis was used to deduce the correlation between the monosaccharide composition ratios of 10 regionally different strains of Lentinula edodes and their in vitro macrophage stimulatory activities. Arabinose, xylose, mannose and galactose were identified as the monosaccharides that could be related to macrophage stimulatory activities. Additional principal component analysis and factor analysis methods were used to treat the same monosaccharide composition ratio data and the compositions of arabinose, xylose, mannose and galactose were found to be important. Interestingly, glucose, although presented in large compositions in all strains presumably forms the backbone of the polysaccharide structures, is not selected as the determinant factor for either structural characteristics or that of the in vitro macrophage stimulatory activities.     

Delay-dependent conditions for guaranteed cost observer-based control of uncertain neutral systems with time-varying delays

Email: chlien{at}mail.nkmu.edu.tw Received on August 10, 2006; Accepted on September 6, 2006 In this paper, delay-dependent guaranteed cost observer-basedcontrol for neutral systems with time-varying delays is considered.Control and observer gains will be given from the linear matrixinequality feasible solutions. Optimal guaranteed cost observer-basedcontrol which will minimize the guaranteed cost of the systemis provided.     

General probabilistic approach to the filtration process

We show experimentally that clogging is basically a matter of the probability of the presence of particles. We describe this process as a function of the main variables of the process, namely, the ratio of particle to mesh hole size, the solid fraction, and the number of grains arriving at each mesh hole during one test, with the help of a simple model, the predictions of which are in very good agreement with our experimental data.     

Microfluidic flow rate detection based on integrated optical fiber cantilever

We demonstrate an integrated microfluidic flow sensor with ultra-wide dynamic range, suitable for high throughput applications such as flow cytometry and particle sorting/counting. A fiber-tip cantilever transduces flow rates to optical signal readout, and we demonstrate a dynamic range from 0 to 1500 microL min(-1) for operation in water. Fiber-optic sensor alignment is guided by preformed microfluidic channels, and the dynamic range can be adjusted in a one-step chemical etch. An overall non-linear response is attributed to the far-field angular distribution of single-mode fiber output.     

Linearly Tunable Emission Colors Obtained from a Fluorescent–Phosphorescent Dual‐Emission Compound by Mechanical Stimuli

Organic mechanoluminochromic materials are mechano/piezo‐responsive and promising for applications in sensors, displays, and data storage devices. However, their switching range of emission is seriously impeded by only one kind of emission (either a fluorescent or phosphorescent peak) in the spectrum of single organic compounds. This study presents a design strategy for pure organic compounds with excellent room‐temperature fluorescent–phosphorescent dual‐emission (rFPDE) properties, which combines the effective factors of dipenylsulfone group, crystalline state, and heavy atom effect. Following the principle of color mixing, myriad emission colors with a wide range from orange to purple and across white zone in a straight line in the chromaticity diagram of the Commission Internationale de l’Eclairage (CIE) can be obtained by simply mechanical grinding the compound. The unique properties could be concentrated on a pure organic compound through this design strategy, which provides a new efficient channel for the discovery of efficient mechano‐responsive organic materials.     

Modification of the large-scale features of high Reynolds number wall turbulence by passive surface obtrusions

A high Reynolds number boundary-layer wind-tunnel facility at New Mexico State University was fitted with a regularly distributed braille surface. The surface was such that braille dots were closely packed in the streamwise direction and sparsely spaced in the spanwise direction. This novel surface had an unexpected influence on the flow: the energy of the very large-scale features of wall turbulence (approximately six-times the boundary-layer thickness in length) became significantly attenuated, even into the logarithmic region. To the author’s knowledge, this is the first experimental study to report a modification of ‘superstructures’ in a rough-wall turbulent boundary layer. The result gives rise to the possibility that flow control through very small, passive surface roughness may be possible at high Reynolds numbers, without the prohibitive drag penalty anticipated heretofore. Evidence was also found for the uninhibited existence of the near-wall cycle, well known to smooth-wall-turbulence researchers, in the spanwise space between roughness elements.     

Triterpenoid contents and anti-inflammatory properties of the methanol extracts of ligustrum species leaves

Ligustrum (privet) plants are used by Chinese physicians to prevent and cure hepatitis and chronic bronchitis. Three common Ligustrum plant spp., namely Ligustrum lucidum Ait. (LL), L. pricei Hayata (LP) and L. sinensis Lour. (LS) were collected to assess their analgesic/anti-inflammatory properties on chemical-induced nociception and carrageenan-induced inflammation in rodents. The methanol extracts from Ligustrum plants leaves effectively inhibited nociceptive responses induced by 1% acetic acid and 1% formalin. LP and LL reduced the edema induced by 1% carrageenan. LP exhibited the best potency of the Ligustrum plants. Furthermore, LP reduced the abdominal Evan's blue extravasations caused by lipopolysaccharide, lipoteichoic acid, autocrines and sodium nitroprusside. The triterpenoid content of the three Ligustrum spp. was measured by high performance liquid chromatography using a photodiode array detector. LP contained the highest content of amyrin, betulinic acid and lupeol. LL had the highest content of oleanolic acid and ursolic acid. The various degrees of analgesic/anti-inflammatory effects among three Ligustrum plants may be related to their different triterpenoid contents. LP is a potential analgesic and anti-inflammatory Ligustrum plant. The effects of LP are partially related to the inhibition of cyclooxygenase-2 activity and a decrease in microvascular permeability via the actions of autocrines and kinins.