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A novel method for the preparation of macroporous chitosan and chitin membranes is suggested, which employs silica particles as porogen. The macroporous chitosan membranes were prepared by (1) casting an acidic chitosan solution that contains silica particles, (2) removing the solvent by evaporation, and (3) dissolving the silica particles by immersing the membranes into an alkaline solution. This simple method provides chitosan membranes with high porosity and satisfactory mechanical strength, the pore sizes of which can be easily controlled by varying the size of silica particles. The effects of various evaporation conditions and amount of silica on the flow rate of water through the membranes were investigated. In order to prevent their dissolution in acidic solutions, the chitosan membranes were cross-linked under alkaline conditions, using epichlorohydrin as the cross-linking agent. Macroporous chitin membranes were prepared by acetylating the chitosan membranes with acetic anhydride in methanol. In contrast to the uncross-linked chitosan membranes, which are soluble in dilute acidic solutions and insoluble in alkaline solutions, the chitin membranes are insoluble both in acidic and basic solutions. Both kinds of membranes can be employed in affinity or ion-exchange bioseparations.

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As a result of the convective flow of solutes through porous membranes, membrane chromatography has a higher capture efficiency and a higher productivity than column chromatography and shows most promising industrial applications for the recovery, isolation, and purification of proteins and enzymes. This paper presents a comprehensive review of the methods for preparation of adsorptive membranes (such as surface modification, in situ copolymerization, direct formation from hydrophilic materials, and functionalized particulate-entrapped membranes) and deals particularly with novel macroporous chitin and chitosan membranes for protein separations developed by the authors.

Clinical dental status indicators were related to OIDP, regardless of the scoring format used to calculate the OIDP index. Clinical indicators that included natural plus replaced teeth were more strongly associated with the OIDP index than their corresponding indicators that included only natural teeth.

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This study investigated the relationship between clinical dental status and eating difficulty in a sample of older Chinese people in Guangxi, China. Sample was selected from people aged 55 years and older who had routine annual health check-ups at a large hospital health centre. The sample consisted of 1,196 dentate people who had clinical oral examinations and face-to-face interviews. Different measures, namely the Index of Eating Difficulty, dissatisfaction with chewing ability and ease of eating certain foods were used to measure eating difficulty. Multiple logistic regression analysis showed that after controlling for the effects of age, sex, occupation, self-assessed social class and self-perceived general health, increased eating difficulty was significantly related with having fewer teeth, fewer posterior and anterior occluding pairs of teeth (both natural teeth only and natural plus replaced teeth), more unfilled posterior spaces, more unfilled anterior spaces, mobile teeth, decayed teeth and roots. In conclusion, clinical dental status was strongly related with eating difficulty in a sample of older Chinese dentate people.

Total flavonoids of Epimedium (TFE) is the main active composition of Epimedium that has been used to treat male reproductive problems. The present aim was to investigate the protective effects of TFE on male mice reproductive system against cyclophosphamide (CP)-induced oxidative injury. The animals were treated with CP to make testicular injury model and the protective effects of TFE were observed. In the CP-treated group, testicular and epididymal weights, sperm count and motility significantly decreased relative to the control group (P < 0.05 and P < 0.01, respectively). Compared with the CP-treated group, TFE (200 and 400 mg/kg) treated mice increased testicular weights by 21.6% and 28.4% (P < 0.05), sperm counts by 81.7% and 148.3% (P < 0.01) and sperm motility by 47.2% and 61.3% (P < 0.01). Meanwhile, the CP-treated group showed enhancement of lipid peroxidation leading to testicular reproductive toxicity. TFE restored these oxidative damages by up-regulating the expression of antioxidant enzymes, especially SOD3 and GPX1. TUNEL assay and histopathological observations provided supportive evidence for above results, and when the dose of TFE increased, the aforesaid improvement became more and more strong. These results demonstrated that TFE exerted beneficially protective effects on the structural and functional damage of male mice reproductive system and reduced apoptosis in spermatogenic cells by inhibiting CP-induced oxidative stress.