Absorption line profile recovery based on TDLS and MEMS micro-mirror for photoacoustic gas sensing.

A novel and efficient absorption line recovery technique is presented. A micro-electromechanical systems (MEMS) mirror driven by an electrothermal actuator is used to generate laser intensity modulation through the mirror reflection. Tunable diode laser spectroscopy (TDLS) and photoacoustic spectroscopy (PAS) are used to recover the target absorption line profile which is compared with the theoretical Voigt profile. The target gas is 0.01% acetylene (C2H2) in a nitrogen host gas. The laser diode wavelength is swept across the P17 absorption line of acetylene at 1535.4 nm by a current ramp, and an erbium-doped fibre amplifier (EDFA) is used to enhance the optical intensity and increase the signal-to-noise ratio (SNR). A SNR of about 35 is obtained with 100 mW laser power from the EDFA. Good agreement is achieved between the experimental results and the theoretical simulation for the P17 absorption line profile.

Studies on purification and properties of antagonistic protein from bacteria SS02 of Paenibacillus daejeonensis / 生物工程学报

The antifungal, anti-bacterical, anti-brine shrimp activities of SD22 isolated from Paenibacillus daejeonensis Bacteria SS02 were studied. The separation steps included ultracentrifugation, ultrafiltration and (NH4)2SO4 fractional precipitation, further purification was performed by SephadexG-75 and DEAE-32 chromatography. Its molecular weight determined by SDS-PAGE was 56.0 kD and its isoelectfic point was 6.4. SD22 was thermostable to some extent and stable to ultraviolet, but sensitive to some of the enzyme. SD22 could kill most pathogens from propagation, such as Rhizoctonia cerealis, Sclerotinia sclerotiorum Physalospora piricala, Trichodema viride, Gliocladium viride, Curvularia leaf spot, Fusarium sp, Fusarium head blight, Beauveria Bassiana, Escherichia coli, Staphylococcus aureus, Bacillus subtilis , Candidal vaginitis, Fusarium oxysporum Schl. emend. Sayder & Hansem et al. The results will be helpful to find out a novel antifungal protein.

Studies on the Isolation and Antibiotic Activities of Endophytes in Paris polyphylla var. Chinensis franch / 微生物学通报

One endophytic stain SS02 was isolated from the underground stems of Paris polyphylla var. Chinensis franch. The ferments of SS02 showed antibiosis activities against 13 kinds of the crop causes germs. The characteristics of morphology,physiological and biochemical showed that SS02 belonged to Bacillus sp. The 16S rDNA of SS02 was PCR and sequenced. The accession of GenBank is AY842144. The one 16S rDNA phylogenetic tree was constructed by comparing with the published 16S rDNA sequences of the relative bacteria species. In the phylogenetic tree SS02 and Paenibacillus daejeonensis was the closest relative with 97.7% sequence similarity. According to the phylogenetic analysis it was identified as Paenibacillus daejeonensis SS02.