Preliminary Studies on Acylation of 10β-OH and 7α-OH in 7-Epi-10-deacetylpaclitaxel

10β-OH can be acylated cleanly when 7α-OH is also free, and thus a facile access to semisynthesis of 7-epi-paclitaxel was proposed. A 2's, 3's-oxazoline paclitaxel analog was serendipitously synthesized

Preliminary studies on the diel vertical migrationof Clanus sinicus (nauplius-adult) larvae atevery stage in the North Huanghai Sea

There have been a lot of papers on the diel vertical migration of marine copepoda published at home and abroad. But so far, no report on the diel vertical migration of the larvae of Clanus sinicus has been seen. The present paper discusses this problem and the result obtained will provide useful reference for further researches on this subject. Moreover, exploring the law of diel vertical migration of the secondary productivity in the ocean will help the development of marieulture and fishing in a scientific way.

PRELIMINARY STUDIES ON THE SYNTHESIS AND CHARACTERIZATION OF OXY-AND THIO-DIACETIC ACID HYDRAZITION AND THEIR FIRST-ROW TRANSITION METAL COMPLEXES

It has been made certain that thio-and oxy-diacetic acid hydrazides are potential anticancer compounds.However,their ability to form complexes with transition metals and the properties of the complexes thus formed have not been studied.Employing a new potential anticancer ligand 1,2-bis(thioacetic acid hydrazide)ethane prepared in our lab,along with ligands oxydiacetic hydrazide and 1,2-bis(oxyacetic acid hydrazide) ethane,a series of 11 new first-row transition metal(M=Zn^(2+),Cu^(2+),Co^(2+), Ni^(2+))complexes with each of the above three ligands have been synthesized and characterized by means of elemental analyses,IR,TG and X-ray powder diffraction.

Preliminary Studies of Speleothem in Central Asia

The Westerlies is important in linking the Northem high latitude, North Atlantic and East Asian monsoon. The location and intensity of the Westerly jet can not only control the climate of central Asia （including northwest arid China）, but also significantly influence the climate of the East Asian monsoon region. However, it remains unclear of the variability of the Westerlies in Asia on multiple timeseales and their global linkage.

Preliminary studies on rice quality of japonica-indica hybrid rice

It has been proved that high yield combina-tions can be obtained via hybridization betweenindica and japonica rice. However, people haveworried about the quality of this kind of ricefor a long time. Our researches were mainlybased on the mating pattern of "japonica malesterile line/indica restorer line" to generateand select elite japonicalinous crosses. Ricequality is shown in table 1 and 2. The scores of rice quality of 7 crossesranged from 56-59, and met the high quality

Preliminary studies on radiant spectrum of the leaves of the paddy and upland rice

To study the property of the radiant spectrum(RS),i.e.absorption,reflectance and trans-mission ratio.Four upland rice varieties i.e.Haogelao,Hongkuo—laoshuya,Chengjiang—ludao,and IRAT—109,and four paddy ricevarieties Xifeng,Akihikari,Zhongbai 4,andYuefu were sown at Beijing on dry land in themiddle May,1992 and 1993.The plants weretreated with drought stress during seedling,booting,heading and flowering stages.It wasrainy season or intermittent irrigation duringother period.The RS and the chlorophyll con-tent of the third leave of seedlings and that offlag leave at heading—flowering period weremeasured with UV—190 model spectrometer.The results are shown in Fig 1 and Fig 2.There were little difference of RS in 800-200 mn and chlorophyll content between theleaves of paddy and upland rice during seedlingstage (Fig 1).However,remarkable differ-

Preliminary study on the distribution of nutrients, organic matter, trace metals in sea surface microlayer in Xiamen Bay and Jiulong Estuary

The enrichment of nutrients (Noa-, Noa-, PO43-), suspended particles, organic matter (POC, PON,DOC) , and trace metals (Cu, Ni, Cd) was determined in the sea surface microlayer of Xiamen Bay and Jiulong Estuary. The mean enrichment factors ([Xi]microlayer/[Xi ]15cm in depth) mostly ranged between 1 . 0 and 2. 0. The dissolved forms were the major forms of the components measured, the enrichment of dissolved organic matter and suspended particles could lead to the changes in the total amount and speciation of nutrients and trace metals. No correlation was observed between sample concentrations, speciation, enrichment factors and sample locations. However, some evidence shows that these parameters are correlated with sea state, indicating the complexity and dynamic nature of the sea surface microlayer.

A Preliminary Study on DNA Mutation Induction of Maize Pollen Implanted by Low Energy N^+ Beam

The maize pollens were implanted with seven different doses of 30 keV N+ beam respectively, The genomic DNA polymorphism from treated pollens were analyzed with 104 primers by using RAPD respectively. The results showed that N^+ beam-induced mutation of maize pollens can result in the change of their DNA bases. The mutation is not properly random and its frequency increases with a rise in 30 keV N+ beam doses. It is conformed with A-G transformation, which is one of the most important factors in DNA bases induced by N+ beam.

A PRELIMINARY STUDY OF THE WATER—SOLUBLE OLIGOPEPTIDES AND AMINO ACIDS OF GINSENG

γ-Amino butyric acid(GABA)and several γ-glutamyl oligopeptides were isolated and identified from water-extract of ginseng.

Preliminary Study on Underwater Ambient Noise Generated by Typhoons

We present a typhoon-generated noise model with which the noise intensity during typhoons can be estimated accurately. The model is verified through experimental study, and the simulation results agree reasonably with the experimental data. The measured noise intensity is approximately proportional to the cube of the local wind speed.

Preliminary study of gonadotropin-releasing analogue (GnRH-A) initiated gonadal development of amphioxus

Amphioxus in the seasonally regressed phase of gonadat development were used in this study. Each sample animal was injected with 40 nanogram of synthetic gonadotropin-releasing hormone analogue (GnRH-A) in distilled water every other day for up to 16 days; control animals received similar volumes of distilled wnter only. Both hormone-treated samples and control animals were examined under microscope every eight days and every twelve days. Then all the animals were killed on the 16th day. Gonads earlier development and a more advanced degree of gametogenesis are in the hormone-treated group than in the control group. Thus, GnRH-A can initiate and accelerate the gonadal development in gonadally regressed am-phioxus. GnRH-A in some form may be important in regulating the gonadal development in amphioxus as well as in vertebrates.

A PRELIMINARY STUDY OF SHORT-TERM EFFICACY OF Nd:YAG LASER PERIPHERAL IRIDOTOMY IN PATIENTS WITH PRIMARY ANGLE CLOSED GLAUCOMA

Q-switched Nd:YAG laser was used for the peripheral iridotomy in 68 cases(80 eyes) of primary angle closed glaucoma. The average number of laser shots is 20.5(1～127 shots), and the average shot energy is 2.5 mJ(0.9～5.6mJ). The successful rate of iris penetration is about 97.6%. The size of the iris hole is not smaller than 0.2mm^2. The kind of the iris is the most important factor that causes the marked variation in laser shots and in laser shot energy. The main complications of Nd:YAG laser iridotomy p...

Some Preliminary Results on Pilot Study of Global Change in China

On the basis of existing data and research results the changes of life supporting environment in China in the history are briefly described. The differences between regional climate variations and climate jump are the very important features and phenomena in estimating the trend of environmental evolution in the future. Finally, it is pointed out that sensitive zone is an ideal place to study global change. Many evidences show that the response of environmental elements in the sensitive zones to global change events is very obvious, so that much attention should be paid to the study of sensitive zone.

Preliminary Feasibility Study on Application of Very Large Scale-Photovoltaic Power Generation in China

Some energy experts believe that solar energy photovoltaic power generation is hopeful to be applied in a large amount and possesses a certain proportion in the structure of energy in the future. In this paper, based on the forecasting of electric load demand and energy structure of power generation in the middle of 21 century, the pictures of VLS-PV power genera- tion is composed, the operation characteristic of VLS-PV power generation and the adaptability of electric power grid for it is analyzed, the ways for transmitting large amount of PV power and the economic and technical bottlenecks for applying VLS-PV power generation are discussed. Finally, the steps and suggestions for developing VLS-PV power generation and its electric power system in China are proposed.

A PRELIMINARY STUDY ON THE RELATIONSHIP BETWEEN MURINE IgE LEVEL AND 3-METHYL-CHOLANTHRENE INDUCED FIBROSARCOMA

The relationship between murine IgE, IgG, and IgG1 level and birosarcoma induced by 3-Methyl-cholanthrene in NIH mice was studied. The results showed that IgE, IgG or IgGl had no significant effect on tumor incidence; the high IgE level could extend the survival time of 3-Methylcholanthrene injected mice (P<0.05) and survival time of tumor bearing mice (P<0.01), while IgG or IgGl could not. The data from this study did not show that IgE, IgG or IgGl had any significant effect on the tumor size and the tumor growth rate. The probable mechanism involved was discussed.

A Preliminary Study on the Present Crustal Stress of Northern South China Sea

The South China Sea （SCS） is the largest marginal sea in West Pacific formed by a combined effect of the Eurasian plate, Pacific plate and India-Australian plate, and is thus considered to be a unique natural laboratory to study oceanic dynamics and tectonic evolutions （Xie et al., 2006; Luan and Zhang, 2009）. Besides, the SCS contains enormous petroleum resources for its favorable conditions of oil-gas generation, accumulation and preservation. It is therefore imperative to intensively study the marine in-situ stress and its controlling factors of the SCS.

Human Pulmonary Hyperpolarized ^(129)Xe MRI: a Preliminary Study

We study the feasibility and safety of human lung hyperpolarized（HP）^（129）Xe magnetic resonance imaging（MRI）.There is no significant change in physiological parameters before and after the examinations of all subjects.Compared with computed tomography, HP^（129）Xe MRI is sensitive to earlier and smaller ventilation defects. The distribution of the HP^（129）Xe MRI signal reflects the pulmonary compliance with the gravity gradient. This is the first application of HP^（129）Xe MRI ventilation imaging in China, and this technology is expected to provide more useful information for clinical practice.

THE PRELIMINARY STUDY ON HMBA-INDUCED DIFFERENTIATION OF THE DRUG-PRETREATED MURINE ERYTHROLEUKEMIA CELLS

Several drug-resistant variants have been developed by growing the parental MEL cells in presence of colchicine, adriamycin and vincristine respectively with stepwise increasing concentration. Both the colchicine-resistant Sc9(ColO) and vincristine-resis-tant Sc9(VCR5) cells displayed an accelerated HMBA-induced commitment to terminal cell differentiation, whereas the adriamycin-resistant SC9 (A 120) showed no acceleration but rather a substantial delay in HMBA-induced differentiation. The studies provide more clues as well as experimental models for further study on the mechanism of induced differentiation of MEL cells.