A Fast,Sensitive and Validated Technique for Eurycomanone and Cordycepin Quantitation using UPLC‒MS/MS

Herbs and herbal based products have been widely used, but some products might contain no herbal ingredient as claimed in the product label. Therefore, it is crucial to develop a fast, sensitive and reliable method to analyze the herbs and their finished products. The roots of Eurycoma longifolia, and the health supplement of E. longifolia and Cordyceps were used as the sample matrices in this study. Sonication assisted extraction was applied to extract the marker compounds, namely eurycomanone and cordycepin from E. longifolia and Cordyceps, respectively. The presence of the marker compounds was established by high throughput ultra-performance liquid chromatography tandem mass spectrometry (UPLC?MS/MS) using a highly sensitive and selective technique of multiple reaction monitoring (MRM). The positive ion transitions in MRM for eurycomanone and cordycepin are m/z 409 → 391 and m/z 252 → 136, respectively. The test method was validated for its robustness, accuracy, precision, linearity, detection and quantitation limits, as well as estimated for its measurement uncertainty.     

On the rational cuspidal subgroup and the rational torsion points of

For two distinct prime numbers , , we compute the rational cuspidal subgroup of and determine the -primary part of the rational torsion subgroup of the old subvariety of for most primes . Some results of Berkovic on the nontriviality of the Mordell-Weil group of some Eisenstein factors of are also refined.

     

Optimization of hydrothermal growth ZnO Nanorods for enhancement of light extraction from GaN blue LEDs

In this study, we report on the enhancement in the light extraction efficiency of GaN blue LEDs topped with ZnO nanorods. The ZnO nanorods were grown by a two-step hydrothermal synthesis with pre-coated ZnO nanoparticles under optimized condition to give the appropriate size and quality, giving an increase in the light output efficiency of 66%. This improvement is attributed to the optimal rod size and spacing with improved thermal dissipation as compared to light extraction from plain GaN surface. During the ZnO growth on the LEDs, 0.55 M of NH₃ was added and the ZnO sample was later annealed at 475 °C in N₂ ambient, to drive out interstitial oxygen atoms from the tetrahedral unstable site. As a result, a high ratio of UV to orange defect band emission was achieved. The two-step growth of ZnO nanorods on GaN LEDs was effective in generating array of ZnO nanorods which serve as reflector to enhance light extraction from LEDs.     

Super-hydrophobic transparent surface by femtosecond laser micro-patterned catalyst thin film for carbon nanotube cluster growth

In this work, super-hydrophobic surfaces were fabricated by femtosecond laser micro-machining and chemical vapor deposition to constitute hybrid scale micro/nano-structures formed by carbon nanotube (CNT) clusters. Nickel thin-film microstructures, functioning as CNT growth catalyst, precisely control the distribution of the CNT clusters. To obtain minimal heat-affected zones, femtosecond laser was used to trim the nickel thin-film coating. Plasma treatment was subsequently carried out to enhance the lotus-leaf effect. The wetting property of the CNT surface is improved from hydrophilicity to super-hydrophobicity at an advancing contact angle of 161 degrees. The dynamic water drop impacting test further confirms its enhanced water-repellent property. Meanwhile, this super-hydrophobic surface exhibits excellent transparency with quartz as the substrate. This hybrid fabrication technique can achieve super-hydrophobic surfaces over a large area, which has potential applications as self-cleaning windows for vehicles, solar cells and high-rise buildings.     

On range and response: Dimensions of process flexibility

There are two dimensions to process flexibility: range versus response. Range is the extent to which a system can adapt, while response is the rate at which the system can adapt. Although both dimensions are important, the existing literature does not analytically examine the response dimension vis-a-vis the range dimension.     

High-density arrays of InGaN nanorings, nanodots, and nanoarrows fabricated by a template-assisted approach

Dense, crystalline arrays of InGaN nanorings, nanodots, and nanoarrows have been fabricated on GaN substrates by template-assisted nano-area selective growth. To create the nanostructures, we have used nanoporous anodic alumina films as templates to pattern nanopores in an SiO2 transfer layer, and then used this patterned SiO2 layer as a template for nitride growth by metalorganic chemical vapor deposition. We have varied the diameter of the deposited nitride nanostructures from 35 to 250 nm by changing the initial anodic alumina template structure. In addition, by controlling the nitride growth time we have created various types of nanostructures, from nanorings to nanoarrows. This structural evolution begins with the nucleation and formation of a nanoring structure, followed by coalescence and growth to form faceted nanodots, and finally lateral overgrowth to form faceted nanoarrows.     

Explicit congruences for the partition function modulo every prime

Let p(n) denote the number of unrestricted partitions of the positive integer n, and let m be a prime $\geq 13$. We prove, for k = 1, explicit congruences of the form where $r_{m,k}, \delta_{m,k}$ are integers depending on m and k and $\phi_{m,k}(z)$ are explicitly computable level one holomorphic modular forms of small weight. We also give theoretical and numerical support that the congruences also hold for k > 1. Our main idea is a level reduction result for the modular forms which originated from Atkin-Lehner. From our result, we deduce periodicity properties for the partition function with short periods which improve upon recent results of K. Ono. Received: 24 January 2002     

Identification of a serine protease inhibitor homologue in Bird's Nest by an integrated proteomics approach.

For centuries, the edible nests of Collocalia spp. ("Bird's Nests") have been used as a Chinese delicacy that had been claimed to be an effective health-giving tonic. However, clinical studies indicated that in Singapore, Bird's Nest is the most common cause of food-induced anaphylaxis in children, which could lead to potentially life-threatening allergenic reactions. The purpose of this study was to characterize the major allergens in Bird's Nest by using the combined technologies of two-dimensional gel electrophoresis (2-DE), immunochemistry, N-terminal protein sequencing, and mass spectrometry. Results from the immunostaining of the Western blots of the Bird's Nest 2-DE separated proteins with the sera from allergic patients indicated the presence of a major allergen of 66 kDa. Initial searches of the matrix assisted laser desorption/ionization--time of flight--mass spectrometry (MALDI-TOF-MS) tryptic peptide masses of the allergen in the SWISS-PROT and NCBI nonredundant databases revealed that this protein was novel. Based on the partial protein sequence information obtained from N-terminal microsequencing and nanoelectrospray-tandem MS, the 66 kDa immunoreactive allergen was found to be homologous to ovoinhibitor, a Kazal-type serine protease inhibitor, which is one of the dominant allergens found in chicken egg white.