pH-responsive lignin-based magnetic nanoparticles for recovery of cellulase

Enzymatic hydrolysis of lignocellulose to produce bioethanol by cellulase is an important method to alleviate the energy crisis. In this paper, in order to overcome the shortcomings of low efficiency, high cost and easy deactivation of cellulase in the process of bio-refinery, pH-responsive lignin-based magnetic nanoparticles (Fe₃O₄/LSQA) were synthesized to immobilize and recover cellulase. It was shown that a high immobilization ratio of 55.52% for cellulase was obtained. Meanwhile, the desorption ratio was 68.27% by adjusting the pH of the system. After five reusing cycles, the desorbed cellulase retained 31.79% of the relative activity due to the pH responsiveness of Fe₃O₄/LSQA. These results not only provide a new idea for the recycling of cellulase, but also broaden the application of industrial lignin and increase the extra value.

[The effects of wireless audio microphones on sentences recognition threshold for hearing aid users in noise]

Objective:This study was aimed to observe the effects of wireless audio microphone on hearing aids effect in noise at different listening distances. Method:Twenty-three subjects with bilateral sensorineural hearing loss, including 17 males and 6 females were fitted with binaural hearing aids. These patients did sentences recognition tests at two different listening distance（1.5 and 3 meters） in noise. The subjects were tested under three conditions, ①with hearing aids alone; ②with the wireless audio microphone alone; ③with hearing aid microphone and mini audio microphone simultaneously. Result:The sentence recognition threshold at 3 meters listening distance is significantly higher than it at 1.5 meters listening distance with hearing aids alone（P<0.05）. There is no significant difference in the sentence recognition threshold between two listening distances when the wireless audio microphone was switched on（P>0.05）. Conclusion:Mini audio microphone can significantly improve hearing aids effect in long distance listening in noise.

[Age dependent changes in mandarin speech perception in normal hearing people]

Objective:To investigate if and when the mandarin speech perception ability deteriorates with age in adults with audiometrically normal hearing sensitivity.Method:The participant group included 75 normal hearing adults sampled from across the entire range of adulthood, of which there are 20 males and 55 femals. The participants were divided into 5 groups with 15 participants per age group: 20-30 years, 31-40 years, 41-50 years, 51-60 years, and 61-70 years. We applied speech perception test using Mandarin Hearing in Noise Test.Result:The speech perception scores were significantly different among the five groups in 0 dB and -5 dB conditions (P<0.001), but they weren't significantly different among the five groups in quiet, 10 dB and 5 dB (P>0.005).There was a significant negative correlation between speech perception and age in -5 dB conditions.Conclusion:When the background noise becomes more severe even for participants with audiomerically normal hearing, it was shown that speech perception declined with age.

Anti-inflammatory effect of novel andrographolide derivatives through inhibition of NO and PGE2 production

Andrographolide (1) is a major diterpene lactone exhibiting anti-inflammatory effects and is found in the plant Andrographis paniculata (Burm. f) Nees, which is widely used in Traditional Chinese Medicine. Synthesis of more effective drugs from andrographolide is very interesting and can prove to be highly useful. In this study, we investigated the anti-inflammatory effects of andrographolide and its derivatives (compounds 2-6) through dimethylbenzene-induced ear edema in mice. Substances under study were administrated intragastrically and the structure-activity relationship was analyzed. Results showed that compounds 5 and 6 significantly inhibited ear edema compared with compound 1 (p<0.05), indicating that the introduction of p-Chlorobenzylidene to C-15 of compound 2 enhances the anti-inflammatory effect. Moreover, compound 6 exhibited the strongest anti-inflammatory effect against ear edema in mice (79.4%; 1.35 mmol/kg, ig) and paw edema in rats (50.4%; 0.90 mmol/kg, ig). In addition, compound 6 significantly (p<0.05) inhibited granuloma formation and reduced the increase in vascular permeability induced by peritoneal injection of 0.6% acetic acid solution in mice. Findings indicate that compound 6 exerts its enhanced anti-inflammatory effects by decreasing serum iNOS activity, NO production, and PGE(2) production.

Synthesis of 3beta, 7alpha, 11alpha-trihydroxy-pregn-21-benzylidene-5-en-20-one derivatives and their cytotoxic activities

A series of novel 3beta, 7alpha, 11alpha-trihydroxy-pregn-21-benzylidene-5-en-20-one derivatives were synthesized and characterized by NMR, HRMS. The pregnenolone (1) was first biotransformed by Mucor circinelloides var lusitanicus to 3beta, 7alpha, 11alpha-trihydroxy-pregn-5-en-20-one (3), then 3 was treated with various benzaldehydes to produce 3beta, 7alpha, 11alpha-trihydroxy-pregn-21-benzylidene-5-en-20-one derivatives. These derivatives showed remarkable activity against EC109 cells. The absolute configuration of 3 was also confirmed by signal-crystal X-ray analysis.

[Freeze-fracturing studies on human erythrocyte membranes effected by external pulsed electrical field]

Electron microscopic observations made on the freeze-fracturing replica of plasma membranes of human erythrocytes exposed to external pulsed electrical field have shown that under experimental conditions, some particles and fibers appear around the cells pulsed by higher intensities than 3 KV/cm. Electrophoretical analysis for the cell suspensions has proved that some of these particles and fibers are membrane proteins and membrane skeleton proteins escaped from cells. On account of this, the stability of cell membrane decreases and the cells are easy to change their shapes and to form pseudopodium like structures and protein free membrane lipids tend to form vesicular structure in cytoplasma. The changes of protein-protein interactions and protein-lipid interactions caused by electrical field are considered as the dominating mechanism of cell membrane electroporation. An argument about intramembrane particles (IMPS) and other possibilities of the contributions to IMPS, for instance, ice crystals formation which related to membrane hydrophilic or hydrophobic properties were discussed in this paper.