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101.
Eric C. Y. Chan Lee Sun New Chun Wei Yap Lin Tang Goh 《Rapid communications in mass spectrometry : RCM》2009,23(3):384-394
The use of hybrid quadrupole ion mobility spectrometry time‐of‐flight mass spectrometry (Q/IMS/TOFMS) in the metabolite profiling of leflunomide (LEF) and acetaminophen (APAP) is presented. The IMS drift times (Td) of the drugs and their metabolites were determined in the IMS/TOFMS experiments and correlated with their exact monoisotopic masses and other in silico generated structural properties, such as connolly molecular area (CMA), connolly solvent‐excluded volume (CSEV), principal moments of inertia along the X, Y and Z Cartesian coordinates (MI‐X, MI‐Y and MI‐Z), inverse mobility and collision cross‐section (CCS). The correlation of Td with these parameters is presented and discussed. IMS/TOF tandem mass spectrometry experiments (MS2 and MS3) were successfully performed on the N‐acetyl‐p‐benzoquinoneimine glutathione (NAPQI‐GSH) adduct derived from the in vitro microsomal metabolism of APAP. As comparison, similar experiments were also performed using hybrid triple quadrupole linear ion trap mass spectrometry (QTRAPMS) and quadrupole time‐of‐flight mass spectrometry (QTOFMS). The abilities to resolve the product ions of the metabolite within the drift tube and fragment the ion mobility resolved product ions in the transfer travelling wave‐enabled stacked ring ion guide (TWIG) demonstrated the potential applicability of the Q/IMS/TOFMS technique in pharmaceutical metabolite profiling. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
102.
Furuya H Nakao H Yamada I Ruan YF Yap YK Yoshimura M Mori Y Sasaki T 《Optics letters》2000,25(21):1588-1590
We developed a Gd(x)Y(1-x)Ca(4)O(BO(3))(3) (GdYCOB) crystal for control of optical birefringence. GdYCOB crystals were successfully used to generate noncritical phase-matched (NCPM) second and third harmonics of 1064-nm lights. However, we observed degradation of third-harmonic-generation (THG) output power and distortion of the beam pattern as a result of photoinduced damage and thermal dephasing. The photoinduced damage was classified into two types. One was gray-track and the other was photorefractive damage. It seems that these types of damage were similar to the types of damage that occurred with KTiOPO(4) and LiNbO(3) crystals. We tried to circumvent this problem by crystal heating. Photoinduced damage of GdYCOB was overcome by elevation of the crystal temperature, and NCPM THG (355-nm) output power from heated GdYCOB increased to 9 mW (62.5 kHz). 相似文献
103.
Chee K. Yap 《Discrete and Computational Geometry》1987,2(1):365-393
LetX be a given set ofn circular and straight line segments in the plane where two segments may interest only at their endpoints. We introduce a new technique that computes the Voronoi diagram ofX inO(n logn) time. This result improves on several previous algorithms for special cases of the problem. The new algorithm is relatively simple, an important factor for the numerous practical applications of the Voronoi diagram.This work was supported by NSF Grants No. DCR-84-01898 and No. DCR-84-01633. 相似文献
104.
Hian-Poh Yap 《Journal of Number Theory》1973,5(4):293-300
The main result of this paper is the complete characterization of maximal sum-free sets in Abelian groups of order 3mn(m ≥ 1) where every prime divisor p of n (if n > 1) is congruent to 1 modulo 3. A few previous results of the author on addition theorems of group theory are also sharpened and/or improved. 相似文献
105.
Mihalcik DJ White JL Tanski JM Zakharov LN Yap GP Incarvito CD Rheingold AL Rabinovich D 《Dalton transactions (Cambridge, England : 2003)》2004,(10):1626-1634
The paramagnetic complexes (TmtBu)CoX (X = Cl, Br, I) have been readily prepared and structurally characterized and provide a convenient entry into cobalt(II) tris(mercaptoimidazolyl)borate chemistry. A number of derivatives, including mononuclear triphenylphosphine adducts [(TmtBu)Co(PPh3)]X and dinuclear compounds [Co2(TmtBu)2X]Y, have been prepared in order to ascertain whether cobalt is a reliable surrogate for zinc in biological systems, particularly in sulfur-rich coordination environments. The structure of the first cobaltaboratrane is also reported. 相似文献
106.
107.
A foveated image is a nonuniform resolution image whose resolution is highest at a point (fovea) but falls off away from the fovea. It can be obtained from a uniform image through a space-variant smoothing process, where the width of the smoothing function is small near the fovea and gradually expanding as the distance from the fovea increases. We treat this process as an integral operator and analyze its kernel. This kernel is dominated by its diagonal in the wavelet bases and thus permits a fast algorithm for foveating images. In addition, the transformed kernel takes a simple form which can be easily computed using a look-up table. This is useful, since in applications the fovea changes rapidly. We describe an application of our approximation algorithm in image visualization over the Internet. 相似文献
108.
Md Fokhrul Islam Yiing C. Yap Feng Li Rosanne M. Guijt Michael C. Breadmore 《Electrophoresis》2020,41(23):2007-2014
A three-dimensional-printed microfluidic device made of a thermoplastic material was used to study the creation of molecular filters by controlled dielectric breakdown. The device was made from acrylonitrile butadiene styrene by a fused deposition modeling three-dimensional printer and consisted of two V-shaped sample compartments separated by 750 µm of extruded plastic gap. Nanofractures were formed in the thin piece of acrylonitrile butadiene styrene by controlled dielectric breakdown by application voltage of 15–20 kV with the voltage terminated when reaching a defined current threshold. Variation of the size of the nanofractures was achieved by both variation of the current threshold and by variation of the ionic strength of the electrolyte used for breakdown. Electrophoretic transport of two proteins, R-phycoerythrin (RPE; <10 nm in size) and fluorescamine-labeled BSA (f-BSA; 2–4 nm), was used to monitor the size and transport properties of the nanofractures. Using 1 mM phosphate buffer, both RPE and f-BSA passed through the nanofractures when the current threshold was set to 25 µA. However, when the threshold was lowered to 10 µA or lower, RPE was restricted from moving through the nanofractures. When we increased the electrolyte concentration during breakdown from 1 to 10 mM phosphate buffer, BSA passed but RPE was blocked when the threshold was equal to, or lower than, 25 µA. This demonstrates that nanofracture size (pore area) is directly related to the breakdown current threshold but inversely related to the concentration of the electrolyte used for the breakdown process. 相似文献
109.
Azadeh Shahbazi Chee Kong Yap Salmijah Surif Alireza Riyahi Bakhtiari Kuhan Chandru 《International journal of environmental analytical chemistry》2013,93(1):14-30
Distribution of polycyclic aromatic hydrocarbons (PAHs) was determined in green mussels (Perna viridis) from various sites in coastal waters of Peninsular Malaysia between August 2004 and January 2007, in order to assess contamination by petroleum hydrocarbons. The range of ∑PAHs detected in mussels was from 766 to 110500 (ng/g lipid wt.). High concentrations of PAHs were found in mussel tissues collected near Penang Bridge. The ratios of methyl phenanthrenes to phenanthrene (∑MP/P ratio) for Penang, Kg. Pasir Puteh and Tebing Runtuh (Johore Straits) were greater than 2, indicating extensive input of petrogenic PAHs. The results indicated that male individuals elevated more considerable concentrations of PAHs in their soft tissues in comparison to female individuals. The results of independent sample T-test showed that there were no significant differences (p > 0.05) between male and female mussels analysed in the Pasir Panjang station. Negative significant correlations (r = ?0.890, p < 0.01) and (r = ?0.0655, p < 0.05), were found between weight and total of PAHs in female and male species, respectively. This indicated that body weight of each individual was not affected by the PAHs concentrations. The present study proposes the use of soft tissue of Perna viridis as a biomonitor of perylene bioavailability and contamination in coastal waters of Peninsular Malaysia. 相似文献
110.
This paper reviews recent advances (mostly after year 2000) in shock and vibration analysis of hard disk drives (HDD) considering
the presence of nonlinearities and discontinuities. Components and dynamic phenomena in HDD where effects of mechanical nonlinearity
and discontinuities are significant are discussed, e.g., head actuator suspension, dimple and slider, head–disk interface,
fluid dynamic bearing, spinning disks, and load/unload dynamics. Ways to model these nonlinearities and discontinuities are
reviewed in detail. Our research on modeling an entire HDD in operating mode subject to shock and vibration using a flexible
multibody dynamics formulation is also presented. The numerical simulation of the shock response of a 1-in. form factor HDD
is presented. A half-sinusoidal acceleration shock is applied at the base of the HDD. Response of the flying height for different
shock amplitudes and duration times is simulated. 相似文献