Quantum-defect theory of resonant charge exchange

We apply the quantum-defect theory for $-1/R^4$ potential to study the resonant charge exchange process. We show that by taking advantage of the partial-wave-insensitive nature of the formulation, resonant charge exchange of the type of $^1$S+$^2$S can be accurately described over a wide range of energies using only three parameters, such as the \textit{gerade} and the \textit{ungerade} $s$ wave scattering lengths, and the atomic polarizability, even at energies where many partial waves contribute to the cross sections. The parameters can be determined experimentally, without having to rely on accurate potential energy surfaces, of which few exist for ion-atom systems. The theory further relates ultracold interactions to interactions at much higher temperatures.Comment: 8 pages, 7 figure

Production of two intermediate taxoids, 2-hydroxy- 5α,10β-diacetoxytaxadiene and 2-hydroxy-5α,10β,14β- triacetoxytaxadiene, from Taxus chinensis cell culture

The production of taxuyunnanine C (Tc) (2α,5α,10β,14β-tetraacetoxytaxa-4(20),11(12)-diene) was significantly enhanced when Taxus chinensis cell cultures were treated with methyl jasmonate (MJA) or 2,3-dihydroxypropyl jasmonate (DHPJA), a newly synthesized jasmonate analog, in combination with in situ absorption. Along with the production of Tc, two intermediate taxoids were produced and purified. On the basis of liquid chromatography-mass spectrometry (LC-MS) and nuclear magnetic resonance (NMR) spectral data, the chemical structures of the two intermediate taxoids were found to be 2-hydroxy-5α,10β-diacetoxytaxadiene and 2-hydroxy-5α,10β,14β- triacetoxytaxadiene. This is the first study to report the production of these two taxoids using plant cell culture.Key words: Taxus chinensis, taxuyunnanine C, methyl jasmonate, 2,3-dihydroxypropyl jasmonate, in situ  absorption, 2-hydroxy-5α,10β-diacetoxytaxadiene, 2-hydroxy-5α,10β,14β-triacetoxytaxadiene

Research on Dual-Variable Integrated Electro-Hydrostatic Actuator

AbstractThe integrated electro-hydrostatic actuator (EHA) with variable displacement and variable rotation speed is researched. In the system, the output of the actuator is changed by controlling the rotation speed of the brushless DC servomotor and the displacement of the servopump. The mathematical model described in state space model is created. The system characteristics are studied based on the point of multiplicative dual variable. And the basic method of control of the system is presented

Quantitative and Qualitative Analysis of Aconitum Alkaloids in Raw and Processed Chuanwu and Caowu by HPLC in Combination with Automated Analytical System and ESI/MS/MS

HPLC in combination with automated analytical system and ESI/MS/MS was used to analyze aconitine (A), mesaconitine (MA), hypaconitine (HA), and their benzoyl analogs in the Chinese herbs Caowu and Chuanwu. First, an HPLC method was developed and validated to determine A, MA, and HA in raw and processed Caowu and Chuanwu. Then an automated analytical system and ESI/MS/MS were applied to analyze these alkaloids and their semihydrolyzed products. The results obtained from automated analytical system are identical to those from ESI/MS/MS, which indicated that the method is a convenient and rapid tool for the qualitative analysis of herbal preparations. Furthermore, HA was little hydrolyzed by heating processes and thus it might account more for the toxicity of processed aconites. Hence, HA could be used as an indicator when one alkaloid is required as a reference to monitor the quality of raw and processed Chuanwu and Caowu. In addition, the raw and processed Chuanwu and Caowu can be distinguished by monitoring the ratio of A and MA to HA

Mitochondrial BNIP3 upregulation precedes endonuclease G translocation in hippocampal neuronal death following oxygen-glucose deprivation

<p>Abstract</p> <p>Background</p> <p>Caspase-independent apoptotic pathways are suggested as a mechanism for the delayed neuronal death following ischemic insult. However, the underlying signalling mechanisms are largely unknown. Recent studies imply the involvement of several mitochondrial proteins, including endonuclease G (EndoG) and Bcl-2/adenovirus E1B 19 kDa-interacting protein (BNIP3), in the pathway of non-neuronal cells.</p> <p>Results</p> <p>In this report, using western blot analysis and immunocytochemistry, we found that EndoG upregulates and translocates from mitochondria to nucleus in a time-dependent manner in cultured hippocampal neurons following oxygen-glucose deprivation (OGD). Moreover, the translocation of EndoG occurs hours before the observable nuclear pyknosis. Importantly, the mitochondrial upregulation of BNIP3 precedes the translocation of EndoG. Forced expression of BNIP3 increases the nuclear translocation of EndoG and neuronal death while knockdown of BNIP3 decreases the OGD-induced nuclear translocation of EndoG and neuronal death.</p> <p>Conclusion</p> <p>These results suggest that BNIP3 and EndoG play important roles in hippocampal neuronal apoptosis following ischemia, and mitochondrial BNIP3 is a signal protein upstream of EndoG that can induce neuronal death.</p