Hydrothermal synthesis and structure of a neutral open-framework zincophosphate

A neutral open-frame work zincophosphate has been hydrothermally synthesized: structure refinement shows that it is composed of Zn4O12 tetramers and infinite Zn-O-Zn chains that are linked by PO4 groups forming one-dimensional 16-membered ring channels along b direction.

PREPARATION AND STRUCTURE OF HALF-OPEN VANADOCENE, V[2,4-(CH3)2C5H5](C5H5)CO

The half-open vanadocene, V[2,4-(CH3)2C5H5](C5H5)CO, was obtained by the reaction of V[2,4-(CH3)2C5H5](C5H5)PMe3 with CO in petroleum ether at room temperature. Its crystal structure was determined by X-ray diffraction technique. The crystal was monoclinic with space group P2(1)/n, a = 16.614(3), b = 7.636(1), c = 19.128(6) angstrom, beta = 99.92(2)-degrees, V = 2390.5(9) angstrom3, and Z = 8. The final R value was 0.043. The V(1)-CPD(1) (half) (PD = 2,4-(CH3)2C5H5) bonds were shorter (0.038 angstrom) than the V(1)-CCP(1) (half) (CP = C5H5) bonds, averaging 2.224(4) versus 2.262(4) angstrom, respectively. 4V[2,4-(CH3)2C5H5](C5H5)CO has been characterized by IR and EPR methods.

Production of astaxanthin from Haematococcus in open pond by two-stage growth one-step process

We have developed a two-stage growth one-step process for cultivation of Haematococcus using a self-designed system that mimics an open pond in the natural environment. The characteristics of this process are green vegetative cell growth and cysts transformation and pigment accumulation that proceed spontaneously and successively in one open photobioreactor. Four strains of Haematococcus (H. pluvialis 26; H. pluvialis 30; H. pluvialis 34; H. pluvialis WZ) were cultured in this imitation system for a duration of 12 days. The changes in cell density and medium pH were closely monitored, and the astaxanthin content and yield of the four Haematococcus strains were measured at the end of 12 days of cultivation. Two of the strains, H. pluvialis 26 and H. pluvialis WZ, were selected as strains suitable for mass culture, resulting in the astaxanthin yield of 51.06 and 40.25 mg L-1 which are equivalent to 2.79 and 2.50% of their dry biomass respectively. Based on the laboratory work, 6 batch cultures of H. pluvialis WZ were conducted successfully to produce astaxanthin in two 100 m(2) open race-way pond by two-stage growth one-step process. The astaxanthin content ranged from 1.61 to 2.48 g 100 g(-1) dry wt., with average astaxanthin content of 2.10 g 100 g(-1) dry wt. Compared with the one-stage production of astaxanthin based on continuous culture, the superiority of our process is that it can accumulate much more astaxanthin in red cysts. Compared with two-stage production of astaxanthin, the advantage of our process is that it does not need to divide the production process into two parts using two bioreactors. The presented work demonstrates the feasibility for producing astaxanthin from Haematococcus using a two-stage growth one-step process in open pond, culture systems that have been successfully used for Spirulina and Chlorella mass culture. The future of Haematococcus astaxanthin production has been also discussed. (C) 2009 Elsevier B.V. All rights reserved.

Seasonal changes in the distribution of dissolved organic nitrogen in coastal and open-ocean waters in the North East Pacific: sources and sinks

The distribution of dissolved organic nitrogen (DON) and nitrate were determined seasonally (winter, spring and summer) during three years along line P, i.e. an E-W transect from the coast of British Columbia, Canada, to Station P (50degreesN, 145degreesW) in the subarctic North East Pacific Ocean. In conjunction, DON measurements were made in the Straits of Juan de Fuca and Georgia within an estuarine system connected to the NE Pacific Ocean. The distribution of DON at the surface showed higher values of 4-17 muM in the Straits relative to values of 4-10 muM encountered along line P, respectively. Along line P, the concentration of DON showed an inshore-offshore gradient at the surface with higher values near the coast. The equation for the conservation of DON showed that horizontal transport of DON (inshore-offshore) was much larger than vertical physical mixing. Horizontal advection of DON-rich waters from the coastal estuarine system to the NE Pacific Ocean was likely the cause of the inshore-offshore gradient in the concentration of DON. Although the concentration of DON was very variable in space and time, it increased from winter to summer, with an average build up of 4.3 muM in the Straits and 0.7 muM in the NE subarctic Pacific. This implied seasonal DON sources of 0.3 mmol N m(-2) d(-1) at Station P and 1.5 mmol N m(-2) d(-1) in the Straits, respectively. These seasonal DON accumulation rates corresponded to about 15-20% of the seasonal nitrate uptake and suggested that there was a small seasonal build up of labile DON at the surface. However, the long residence times of 180-1560 d indicated that the most of the DON pool in surface waters was refractory in two very different productivity regimes of the NE Pacific. (C) 2002 Elsevier Science Ltd. All rights reserved.