Biomass,nutrient uptake and fatty acid composition of Chlamydomonas sp.ICE-L in response to different nitrogen sources

Nitrogen removal from media by microalgae provides the potential benefit of producing lipids for biodiesel and biomass. However, research is limited on algal growth and biomass under different nitrogen sources and provides little insight in terms of biofuel production. We studied the influences of nitrogen sources on cell growth and lipid accumulation of Chlamydomonas sp. ICE-L, one of a promising oil rich micro algal species. Chlamydomonas sp.ICE-L grown in NH_4 Cl medium had maximum growth rate. While the highest dry biomass of 0.28 g/L was obtained in media containing NH_4NO_3, the highest lipid content of 0.21 g/g was achieved under nitrogendeficiency condition with a dry biomass of 0.24 g/L. In terms of total polyunsaturated fatty acids（PUFAs）production, NH_4NO_3 and NH_4 Cl media performed better than nitrogen-deficiency and KNO_3 media.Furthermore, NH_4NO_3 and NH_4 Cl media elucidated better results on C18：3 and C20：5 productions while KNO_3and-N conditions were better in C16：0, C18：1 and C18：2, comparatively.

Review:Do Horses Receive Optimum Amounts of Glutamine in Their Diets?

In some species of growing mammals glutamine is an essential amino acid that,if inadequate in the diet,is needed for normal growth and development.It is thus sometimes considered to be a conditionally essential amino acid in some species.A review of studies that have measured L-glutamine concentrations([glutamine])in horses demonstrates that plasma[glutamine]has routinely been reported to be much lower(~330μmol/L)than in other mammals(>600μmol/L).Plasma[glutamine]represents the balance between intestinal transport into the blood after hepatic first pass,tissue synthesis and cellular extraction.The hypothesis is proposed that sustained low plasma[glutamine]represents a chronic state of sub-optimal glutamine intake and glutamine synthesis that does not meet the requirements for optimum health.While this may be without serious consequence in feral and sedentary horses,there is evidence that provision of supplemental dietary glutamine ameliorates a number of health consequences,particularly in horses with elevated metabolic demands.The present review provides evidence that glutamine is very important(and perhaps essential)for intestinal epithelial cells in mammals including horses,that horses with low plasma[glutamine]represents a sub-optimal state of well-being,and that horses supplemented with glutamine exhibit physiological and health benefits.

Corrosion damage behaviors of rubber O-rings under simulated acid fracturing conditions

To explore the damage behavior of O-ring in acid environment,a high-temperature and high-pressure(HTHP)autoclave was used to simulate the service environment of O-ring,and then 168h corrosion test of hydrogenated nitrile butadiene rubber(HNBR)and fluororubber(FM)O-rings were carried out.The corrosion damage behaviors of two kinds of rubber O-rings in the acidizing fluid were studied through determining their tensile strength,elongation at break,hardness,permanent compressive deformation,tensile fracture morphology and sealing property.The results showed that the crosssectional area and the compression permanent deformation increased,the tensile strength and hardness decreased when the HNBR and FM O-rings under the free state were subjected to acid corrosion.The elongation at break of HNBR decreased,and that of FM rubber increased greatly.Similar with free state,the HNBR and FM O-rings under sealed state also presented the same variation trend.The decrease in the reliability of the O-rings under the sealed state was less significant than that in the free state.In the test,tensile fractures were mostly brittle fractures,HNBR and FM O-rings had obvious corrosion damages such as deformation and swelling.The results could provide a technical basis for the selection of sealing materials,tool optimization design,and construction work in oil and gas fields.