[Correlation study between accumulation of triterpenoids and expression of relative genes in Alisma orientale].

To research the correlation between accumulation of triterpenoids and expression of key enzymes genes in triterpenoid biosynthesis of Alisma orientale,the study utilized UPLC-MS/MS method to detect eight triterpenoids content in the tuber of A. orientale from different growth stages,including alisol A,alisol A 24 acetate,alisol B,alisol B 23 acetate,alisol C 23 acetate,alisol F,alisol F 24 acetate and alisol G,and then the Real time quantitative PCR was used to analyze the expression of key enzymes genes HMGR and FPPS in triterpenoid biosynthesis. Correlation analysis showed that there was a significant positive relation between the total growth of these eight triterpenoids and the average relative expression of HMGR and FPPS(HMGR: r = 0. 998,P<0. 01; FPPS: r = 0. 957,P<0. 05),respectively. Therefore,the study preliminarily determined that HMGR and FPPS genes could regulate the biosynthesis of triterpenoids in A. orientale,which laid a foundation for further research on the biosynthesis and regulation mechanism of triterpenoids in A. orientale.

Enhancing the differentiation of walking and standing via the ratio of plantar pressures.

Differentiation of standing and walking based on plantar pressures is helpful in developing strategies to reduce health risks in the workplace. In order to improve the differentiation ability, the paper proposes a new metric for posture differentiation, that is, the pressure ratio on the two anatomical plantar regions. The plantar pressures were collected from 30 persons during walking and standing. After verifying the normal distribution of the pressure ratio by the Monte Carlo method, two-way repeated-measures ANOVA was conducted for the pressure ratios. The advantage of the pressure ratio over two conventional pressure metrics (the average pressure and the peak pressure) is demonstrated by its much larger size effect. Furthermore, the pressure ratio permits to establish value ranges corresponding to walking and standing, which are less influenced by specific person factors, thus facilitating the design of a standardized posture recognition system. The underlying mechanism underlying the pressure ratio is discussed from the aspect of biomechanics of movement.

[Study on fingerprint spectrum of loquat leaf by HPLC].

OBJECTIVE: To establish the fingerprint spectrum of Loquat Leaf of Fujian authentic medicinal herbs by HPCE. METHODS: The HPLC fingerprints of Loquat Leaf were obtained from instrument HP1100. The HPLC separation was performed on a Eclipse XDB-C18 (4.6 mm x 150 mm, 5 microm) analytical column diluted with methanol-l% glacial acetic acid (90:10) at the flow rate of 1.0 ml/min. The temperature of column was room temperature. The UV detection wavelength was 215 nm. RESULTS: Detected 12 batches samples of different species Lopuat Leaf Fingerprint by the method of HPLC. Eight peaks in the chromatogram were common. All the similarity were above 0.9, the fingerprints integer feature were coincident essentially. CONCLUSION: The method is convenient, quick and exact, and its reproducibility is good. It will be a scientific reference for qualitation identification and quality evaluation of Loquat Leaf.

Attenuation of laser-generated shock waves in Plexiglas.

A simple analytic model is derived for describing the attenuation of a shock wave in a Plexiglas plate. At the same time, experimental measurements are presented with a well-designed optical-fiber sensor based on detection-beam deflection. The amplitude of the shock-wave pressure is measured experimentally and calculated numerically for analytic expressions at different distances from the region of the surface breakdown by the radiation of a single-pulse Nd:YAG laser. Good agreement between the experimental and the calculated values of the shock-wave pressure is established.

Shock-wave propagation and cavitation bubble oscillation by Nd:YAG laser ablation of a metal in water.

A highly sensitive fiber-optic sensor based on optical beam deflection is applied for investigating the propagation of a laser-induced plasma shock wave, the oscillation of a cavitation bubble diameter, and the development of a bubble-collapse-induced shock wave when a Nd:YAG laser pulse is focused upon an aluminum surface in water. By the sequence of experimental waveforms detected at different distances, the attenuation properties of the plasma shock wave and of the bubble-collapse-induced shock wave are obtained. Besides, based on characteristic signals, both the maximum and the minimum bubble radii at each oscillation cycle are determined, as are the corresponding oscillating periods.