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Objective To investigate the potential effect of Ginkgo biloba extract (GBE) on the prevention and treatment of nonalcoholic fatty liver disease (NAFLD). Methods Male Wistar rats were divided into 4 groups (the control group, GBE group, high-fat diet [HFD] group and HFD + GBE group). The human hepatocellular carcinoma cell line (HepG2) was treated with GBE and its flavonoid ingredients. The fatty acid composition of the rat liver was analyzed with gas chromatography/time-of-flight mass spectrometry (GC/TOFMS). Triglyceride contents of both the rat liver and HepG2 cells were measured by enzymatic colorimetric method. The expressions of fatty acid metabolism-related genes were analyzed with real-time reverse transcription-polymerase chain reaction (RT-PCR). The protein expression and enzymatic activity were subsequently measured. Results In rat livers, GBE reduced the elevations of hepatic triglyceride contents caused by HFD and the increased hepatic fatty acids were differentially affected by GBE. Notably, the expression and total activity of the fatty acid β-oxidation rate-limiting enzyme, carnitine palmitoyltransferase 1a (CPT1A), were also promoted with GBE ingestion. In HepG2 cells, GBE and its ingredients, quercetin, kaempferol and isorhamnetin, could decrease the cellular triglyceride content and upregulate the expression and total activity of CPT1A, respectively. Conclusions The triglyceride-lowering effect of GBE on the HFD rat liver is closely associated with the increased expression and activity of CPT1A, and the flavonoid ingredients are the major contributors of GBE.

Further investigation on the leaves of Isodon sculponeatus afforded two new ent-kaurane diterpenoids, sculponeatins J and K. Their structures were elucidated on the basis of their spectral properties, as well as X-ray crystallographic analysis. The cytotoxicities of these two new compounds against human tumor cells K562 and T24 were also tested, and sculponeatin J showed significant inhibitory effects with IC50 values less than 1.0 μg/mL.

Focal loci are often required in earthquake location. However, it is extremely difficult to analytically express them when the earthquake lies in a complex model. Therefore, the calculation of focal loci is usually limited to simple media. In this paper, we present a method for calculating focal loci in complex media by means of a minimum traveltime tree algorithm for ray tracing. The focal loci are constrained with observed arrival time differences at seismic stations so that the problem of origin time is evaded. From all the model nodes, we select a small part with smaller absolute residuals between observed and calculated traveltime differences (or double differences) as reference points of the focal locus. The reference point with minimum double difference is assigned as an initial point. The ray paths from the initial point to the other selected reference points in the doubledifference field actually represent the focal locus, which are traced with a minimum traveltime tree algorithm. When the obtained focal locus is rather rough due to the excessive amount of selected reference points, it can be improved by removing some ray paths to the reference points that there are less rays go through. Additionally, the stop condition of the minimum traveltime tree algorithm is modified to reduce computational time. The results of numerical tests including velocity perturbations and noisy arrival data in a laterally heterogeneous model indicate that the presented method is feasible.

The minimum travel time tree algorithm for tracing rays in isotropic media is extended to transversely isotropic (TI) media, which exist extensively in the Earth. The extended algorithm is suitable to heterogeneous TI media with tilted axes of symmetry. Construction of the minimum travel time tree is implemented efficiently with a modified algorithm in which propagation areas of secondary waves are not fixed but adjusted dynamically with spread of seismic waves in media. As for weakly anisotropic media, we use a new approximate formula of group velocity in terms of the ray angle. The approximate velocity formula is based on the expression of phase angle in terms of ray angle, and fits well the exact values for three independent modes of seismic waves (qP, qSV and qSH). Homogeneous and heterogeneous modes are calculated with the extended minimum travel time tree algorithm. We compare our results corresponding to the heterogeneous model with those obtained by a finite-element method for elastic anisotropic waves and find that they are in excellent agreement. The extended ray tracing method can be applied to further researches on depth migration and seismic tomography for TI media.

Layered and blocked homogeneous models are usually used in interpreting wide-angle reflection data to forward model travel times and ray paths of wide-angle reflection waves when we research crust structure by deep seismic exploration. In order to make the model approach the Earth, the size of the model has to be large. On the other hand, for obtaining accurate travel times and rays calculated with minimum travel time tree algorithm, the model elements have to be small, and thus the efficiency of calculation is decreased. In this paper, a double-grid scheme is employed in calculation of travel times and ray paths in order to fast and reliably interpret deep sounding data. In the double-grid algorithm, the model is covered with sparse and dense grids. Nodes in the sparse gird are calculated in the same way as in the single-grid algorithm; as for the ones in the dense gird, they are done only if they are in the neighborhoods of source and geophone nodes, and the ones where velocity gradients are not zero, and the propagation areas of secondary waves are larger for interface boundary nodes than for the ones within homogenous media. The numerical example shows that the double-grid algorithm has much higher calculation efficiency than the single-gird one under the same accuracy condition for large layered and blocked homogenous models.

It is one of important contents of multiwave exploration seismology to calculate traveltimes of converted waves in complex media. This paper puts forward an improved minimum traveltime tree algorithm for fast calculation of converted wave traveltimes in 3-D complex media, which is based on Huygens' principle and Fermat's principle. First, we improve the basic minimum traveltime tree algorithm for first-break waves in order to speed calculation of 3-D converted wave traveltimes. Second, we extend the improved algorithm for first- break waves to converted waves by separating converted waves into downward and upward traveling waves and tracing them respectively. The numerical example shows that the method introduced in this paper for calculating converted wave traveltimes is fast and robust, and can be applied to practical multiwave seismic exploration.

A novel 13(12 --> 11)abeo-abietane skeletal diterpenoid, micranthin C (1), was isolated from Isodon lophanthoids var. micranthus. Its structure was determined by various spectroscopic techniques and finally confirmed by single-crystal X-ray diffraction.

Further investigation on the aerial parts of Isodon enanderianus afforded a novel asymmetric ent-kauranoid dimer, enanderinanin J (1). The structure of the dimer was elucidated by mews of spectroscopic methods (Including 2D NMR techniques). Enanderinanin J was a dimer of xerophilusin A and probably formed by [4 + 2] cycloaddition.

A novel 13(12 --> 11)abeo-abietane skeletal diterpenoid, micranthin C (1), was isolated from Isodon lophanthoids var. micranthus. Its structure was determined by various spectroscopic techniques and finally confirmed by single-crystal X-ray diffraction.

Three new 11beta,16beta-epoxy-ent-kauranoids melissoidesins 1-K (1-3) and one new ent-abietanoid melissoidesin L (4) were obtained from the aerial parts of Isodon melissoides (BENTHAM) H. HARA, their structures were established on the basis of the spectral methods, especially two dimensional (2D) NMR spectroscopy.