Taxol synthesis

Being a complex diterpenoid, the potent anticancer drug, Taxol, requires complicated steps for its biosynthesis. In the present article, recent advances on Taxol biosynthesis pathway are reviewed, including many recently reported genes that regulate Taxol biosynthesis. To meet the urgent need of clinic and scientific research, besides Taxus supply, other approaches to obtain Taxol have also been discussed here.Keywords: biosynthesis pathway, cell culture, endophytic fungi, Taxol, Taxu

Experimental demonstration of a fiber-optic gas sensor network addressed by FMCW

Author name used in this publication: H. L. HoAuthor name used in this publication: W. JinAuthor name used in this publication: M. S. DemokanAuthor name used in this publication: K. C. Chan2000-2001 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Effects of a Chinese Medicinal Plant Radix Astragali on the Ovariectomized Female Rats

Perimenopausal syndrome occurs during the transition to menopause. Complementary and alternative medicine, especially Chinese medicinal plants, has manifested significant effects in alleviating perimenopausal symptoms. However, little research has been focused on the effects of Chinese medicinal plant on the immune function of the perimenopausal women. The present study aimed to explore the effects of Radix Astragali (RA) on the sex hormone levels and the interleukins of the ovariectomized female rats. 24 female Sprague-Dawley (SD) rats were randomly divided into model control group (MOD group), sham-operation group (SHAM group), RA group and estrogen group (EST group). After all the treatment ended, the serum levels of estradiol (E2), follicle stimulating hormone (FSH), luteinizing hormone (LH), interleukin-2 (IL-2), and interleukin-8 (IL-8) were measured using enzyme-linked immune-sorbent assay (ELISA) and the uterus was removed and weighed after blood exsanguinations immediately. In the MOD group, the serum levels of E2 were significantly lower, and the serum levels of FSH and LH were markedly higher than those of the RA group, EST group and SHAM group (P<0.05). In the RA group, the serum levels of E2 were significantly lower, and the serum levels of FSH were markedly higher than those of the SHAM group and EST group, respectively. In the MOD group, the serum levels of IL-2 and IL-8 were significantly lower than those of the RA group, EST group and SHAM group (P<0.05), and no marked differences existed among RA group, EST group and SHAM group in the serum levels of IL-2 and IL-8 (P>0.05). The uterine weight of the rats in the RA group, EST group and SHAM group were significantly higher than those of the rats in MOD group (P<0.05). There were no marked differences among the rats from RA group, EST group and SHAM group on the uterine weight (P>0.05). It is concluded that RA can significantly improve the immune functions of the ovariectomized female rats, although it cannot change the sex hormones levels as significantly as estrogen

Phase diagram and spin-glass phenomena in electron-doped La1-xHfxMnO3 (0.05 ≤ x ≤ 0.3) manganite oxides

The effects of tetravalent hafnium doping on the structural, transport, and magnetic properties of polycrystalline La1−xHfxMnO3 (LHMO) (0.05 ≤ x ≤ 0.3) were investigated systematically. LHMO exhibited a typical colossal magnetoresistance effect via the double-exchange between Mn2+ and Mn3+ ions, instead of that between Mn3+ and Mn4+ ions in hole-doped manganites. A phase diagram was obtained for the first time through magnetization and resistance measurements in a broad temperature range. As the Hf concentration varied from x = 0.05 to 0.3, the Curie point and metal-to-insulator transition temperature increased significantly, whereas the magnetization and resistivity decreased remarkably. An abnormal enhancement of the magnetization was observed at about 42 K. It was further confirmed that a second magnetic phase MnO2 in LHMO gives rise to such a phenomenon. The possible causes are discussed in detail. The dynamic magnetic properties of LHMO, including relaxation and aging processes, were studied, demonstrating a spin-glass state at low temperature accompanied by a ferromagnetic phase.published_or_final_versio

Magnetic field mediated low-temperature resistivity upturn in electron-doped La1-xHfxMnO3 manganite oxides

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Experimental study on Shear capacity of cementitious composite RPC Beams using high strength steel

Reactive Powder Concrete (RPC) is a special concrete where the microstructure is optimized by precise gradation of all particles in the mix to yield maximum density. Therefore, Reactive Powder Concrete exhibits ultra-high strength and durability. The high strength reinforcement (HSR) has high strength and good plastic deformation properties. The combination of RPC and high strength reinforcement can fully exploit their respective advantages. At present, there is little research on shear capacity of HSR reinforced RPC concrete beams, neither are design guidelines for this type of structure. Therefore, it is imperative to make detailed investigations on the shear capacity of this type of concrete. In this paper, thirty-two full scale shear tests of high strength steel reinforced RPC beams were carried out. The parameters affecting the shear capacity of this type of structures were studied, the major failure modes of this type structure due to shear are identified

Suppression of photoconductivity by magnetic field in epitaxial manganite thin films

The erasure of photoinduced resistance (PR) by the magnetic field was investigated in manganite films. The PR was significantly suppressed when a magnetic field was introduced at low temperature. The decrease (or increase) of PR with increment of magnetic field was observed in ferromagnetic (or paramagnetic) phases of films, respectively. Our results are suggested to be the coaction of two effects under magnetic fields: (i) the reorientation of domains and spin directions of photoexcited carriers and (ii) electrons trapped around oxygen vacancies released and recombined with majority carriers in films. The interplay of the external fields is a good demonstration of the strong coupling between spins and charges in colossal magnetoresistance materials. © 2012 American Institute of Physics.published_or_final_versio

Disease-Associated Mutations Prevent GPR56-Collagen III Interaction

GPR56 is a member of the adhesion G protein-coupled receptor (GPCR) family. Mutations in GPR56 cause a devastating human brain malformation called bilateral frontoparietal polymicrogyria (BFPP). Using the N-terminal fragment of GPR56 (GPR56N) as a probe, we have recently demonstrated that collagen III is the ligand of GPR56 in the developing brain. In this report, we discover a new functional domain in GPR56N, the ligand binding domain. This domain contains four disease-associated mutations and two N-glycosylation sites. Our study reveals that although glycosylation is not required for ligand binding, each of the four disease-associated mutations completely abolish the ligand binding ability of GPR56. Our data indicates that these four single missense mutations cause BFPP mostly by abolishing the ability of GPR56 to bind to its ligand, collagen III, in addition to affecting GPR56 protein surface expression as previously shown

Study of psi(2S) decays to X J/psi

Using J/psi -> mu^+ mu^- decays from a sample of approximately 4 million psi(2S) events collected with the BESI detector, the branching fractions of psi(2S) -> eta J/psi, pi^0 pi^0 J/psi, and anything J/psi normalized to that of psi(2S) -> pi^+ pi^- J/psi are measured. The results are B(psi(2S) -> eta J/psi)/B(psi(2S) -> pi^+ pi^- J/psi) = 0.098 \pm 0.005 \pm 0.010, B(psi(2S) -> pi^0 pi^0 J/psi)/B(psi(2S) -> pi^+ pi^- J/psi) = 0.570 \pm 0.009 \pm 0.026, and B(psi(2S) -> anything J/psi)/B(psi(2S) -> pi^+ pi^- J/psi) = 1.867 \pm 0.026 \pm 0.055.Comment: 13 pages, 8 figure