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Nitrogen source is one of the important factors that affect the microalgae growth and lipid accumulation. We studied the effects of various nitrogen sources (i.e. NaNO3, CO(NH2)2, NH4Cl and CH3COONH4) and amount on the growth density, lipid yield, and eicosapentaenoic acid (EPA) content of Nannochloropsis oculata by single factor experimental method. The results show that N. oculata preferred NH4+ as nitrogen source rather than NO3- and CO(NH2)2. NH4+ could promote the growth and lipid accumulation of N. oculata. With the increase of nitrogen concentration, the biomass and the content of polyunsaturated fatty acid (PUFA) increased, but the content of lipid decreased. CH3COONH4 was the most suitable for growth, accumulation of lipid and EPA of N. oculata among the four investigated nitrogen sources. The optimal concentration was 5.29 mmol/L.

Effects of carbon sources (Na2CO3, NaHCO3 and glucose) and concentration of NaHCO3 on the growth density and lipid contents of Nannochloropsis oculata were studied. N. oculata preferred inorganic carbon to glucose, the growth density and lipid content of algae cultured with NaHCO3 were higher than that with glucose. The effects of concentration of NaHCO3 on growth density and lipid content were related to inoculation density and nitrogen level. In high nitrogen level, the concentration of NaHCO3 had little effect on the growth density, but in low nitrogen level, the growth density increased at first, and then decreased with the increase of concentration of NaHCO3. Based on the results we suggest that an optimum ratio of carbon to nitrogen was existed. Furthermore, we found the optimum ratio was changed with inoculation density. The optimum ratio of carbon to nitrogen was 3 when inoculation density was OD440 of 0.10, the optimum ratio increased to 5 with OD440 of 0.70. Concentration of NaHCO3 and ratio of carbon to nitrogen had significant effects on the lipid content and productivity. Lipid content reached the highest value when the ratio of carbon to nitrogen was 1 with experimental range of nitrogen level and inoculation density. The lipid productivity was 56.7 mg/(L.d) , and the EPA productivity was 6.5 mg/(L.d) at optimum cultivation condition with NaHCO3 as carbon source, the ratio of carbon to nitrogen at 1, the concentration of NaNO3 at 0.225 g/L, and the inoculation density with OD440 of 0.70.

Endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) were developed for the treatment of benign lesions and early superficial esophageal cancers in the gastrointestinal (GI) tract. However, esophageal strictures frequently develop in patients who undergo EMR/ESD. Therefore, we aimed to investigate the clinical value of preventive balloon dilatation (BD) for esophageal diseases following endoscopic therapy. A total of 30 patients who had received EMR or ESD were enrolled in the study. Preventive BD was carried out for 12 cases within 1 week following EMR/ESD. The remaining 18 cases were not subjected to preventive BD and were used as an historic control. The results revealed that no complications, including esophageal stenosis and dysphagia, were observed in the patients who received preventive BD. In the control group, seven cases experienced dysphagia, of which two were released without clinical treatment and the other five were released following two or three BD procedures. The results indicate that preventive BD is an effective treatment for patients with esophageal diseases following EMR and should be considered at an early stage when the mucosal injury exceeds two-thirds of the esophageal lumen.