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Solution Volume (solution + volume)
Selected AbstractsGrowth of big single crystals of a new magnetic superconducting double perovskite Ba2PrRu1,xCuxO6CRYSTAL RESEARCH AND TECHNOLOGY, Issue 2 2006S. M. Rao Abstract Single crystals of Ba2PrRu1,xCuxO6 with x = 0 to 0.2, have been grown from high temperature solutions of a mixture of PbO-PbF2 in the temperature range 1100,1200 °C. Thin crystals with mostly a hexagonal and triangular plate like habit measuring up to 1,2 mm across and 0.1,0.2 mm thick were obtained. The size, quality and morphology of the crystals were improved by varying the solution volume as well as additives like B2O3. Large crystals measuring up to 3 mm across and 0.3 to 0.5 mm thick were obtained with 5,7 wt% solute concentration and 0.51 wt% of B2O3. The ZFC curves exhibit a spin glass like behavior with x = 0 and a superconducting transition at 8 to 11 K depending on x = 0.05 to 0.1. The transition was also influenced by the growth temperature and post growth annealing. Powder x-ray diffraction, EDS and Raman spectroscopic measurements confirm the presence of Cu in the crystals. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Protein crystal growth with a two-liquid system and stirring solutionJOURNAL OF SYNCHROTRON RADIATION, Issue 1 2004Hiroaki Adachi We developed two novel methods for growing large, high-quality protein crystals. A two-liquid system enables the convenient extraction of protein crystals without causing mechanical damage due to growth at the interface between two liquids. Since this system does not require limitations on solution volume, it is also suitable for the seed technique, and for growing large crystals. Another new concept is the mild stirring of the solution using the Floating And Stirring Technique (FAST) and the Micro-stirring technique. When compared to conventional techniques, both techniques result in a reduced number of crystals, as well as the growth of large crystals. [source] Improved method for isotopic and quantitative analysis of dissolved inorganic carbon in natural water samplesRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 15 2006Nelly Assayag We present here an improved and reliable method for measuring the concentration of dissolved inorganic carbon (DIC) and its isotope composition (,13CDIC) in natural water samples. Our apparatus, a gas chromatograph coupled to an isotope ratio mass spectrometer (GCIRMS), runs in a quasi-automated mode and is able to analyze about 50 water samples per day. The whole procedure (sample preparation, CO2(g),CO2(aq) equilibration time and GCIRMS analysis) requires 2 days. It consists of injecting an aliquot of water into a H3PO4 -loaded and He-flushed 12,mL glass tube. The H3PO4 reacts with the water and converts the DIC into aqueous and gaseous CO2. After a CO2(g),CO2(aq) equilibration time of between 15 and 24,h, a portion of the headspace gas (mainly CO2+He) is introduced into the GCIRMS, to measure the carbon isotope ratio of the released CO2(g), from which the ,13CDIC is determined via a calibration procedure. For standard solutions with DIC concentrations ranging from 1 to 25,mmol,·,L,1 and solution volume of 1,mL (high DIC concentration samples) or 5,mL (low DIC concentration samples), ,13CDIC values are determined with a precision (1,) better than 0.1,. Compared with previously published headspace equilibration methods, the major improvement presented here is the development of a calibration procedure which takes the carbon isotope fractionation associated with the CO2(g),CO2(aq) partition into account: the set of standard solutions and samples has to be prepared and analyzed with the same ,gas/liquid' and ,H3PO4/water' volume ratios. A set of natural water samples (lake, river and hydrothermal springs) was analyzed to demonstrate the utility of this new method. Copyright © 2006 John Wiley & Sons, Ltd. [source] Radiographic Comparison of Three Methods for Nasal Saline Irrigation,THE LARYNGOSCOPE, Issue 8 2002David E. L. Olson MD Abstract Objective To compare intranasal distribution of saline solution delivered by three popular methods for nasal saline irrigation. Study Design Prospective, controlled comparison. Methods Eight healthy adult volunteers received nasal irrigation with 40 mL of isotonic, nonionic contrast material immediately before having coronal computed tomography to visualize distribution of solution in the paranasal sinuses. For each study subject, three methods of irrigation were used: irrigation using positive-pressure irrigation, irrigation using negative-pressure irrigation, and irrigation using a nebulizer. For each subject, three-dimensional computer reconstructions of the irrigated paranasal sinus airspaces were used to compare contrast solution volume and distribution achieved by the three methods. Results Of the three methods used, two methods, positive-pressure and negative-pressure irrigation, distributed contrast solution widely to ethmoid and maxillary sinuses, but distribution of contrast solution was more uniform using positive-pressure irrigation than using negative-pressure irrigation. The nebulization method distributed contrast solution poorly and resulted in a significantly lower volume of retained contrast solution (P <.05). Conclusion Judged solely on the basis of solution distribution in the nasal sinuses, nasal irrigation is effective when either positive-pressure or negative-pressure irrigation is used but is ineffective when a nebulizer is used. [source] Development of multilayered cell-hydrogel composites using an acoustic focusing techniqueBIOTECHNOLOGY PROGRESS, Issue 2 2010Jason P. Mazzoccoli Abstract Multilayered composites, composed of mammalian cells arranged in a hydrogel, have been prepared using an acoustic focusing technique. Acoustic focusing is a simple, nonchemical technique that allows for the fast arrangement of cells in matrices where the control of cell geometry is beneficial. Breast cancer cells (MDA-MB231) were dispersed in a 30 wt % solution of poly(ethylene glycol) diacrylate (PEGDA) of molecular weight 400 at a density of 5 × 106 cells/mL of PEGDA solution. An ultrasonic field was used to organize the cells before polymerization of PEGDA. Disk-shaped hydrogel composites, typically 1 cm in diameter and 2-mm thick were prepared based on a PEGDA solution volume of 130 ,L. At an acoustic frequency of 2.32 MHz, composites having cells positioned within concentric cylindrical shells interspersed with zones of cell-free hydrogel were produced. The cells were located in annuli approximately 80-,m thick and about 300 ,m apart. The structure and viability of the cells within these constructs were studied using a fluorescent LIVE/DEAD assay. The viability of the cells was on the order of 50%. For the conditions used in this study, cell death was primarily attributed to exposure of cells to the PEGDA solution prior to polymerization, rather than adverse effects of polymerization or the sound field itself. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2010 [source] Preparation of enantiomeric gossypol by crystallization,CHIRALITY, Issue 6 2003Michael K. Dowd Abstract Large enantiomorphic crystals of gossypol-acetone (1:3) were grown from acetone solutions of rac -gossypol-acetic acid (1:1) at 4°C. By controlling the initial gossypol concentration, crystallization time, and solution volume, single crystals were grown that weighed >50 mg, equivalent to >37 mg of enantiomeric gossypol. Even larger crystals were possible, but it was difficult to produce these reliably without contamination of the antipode. Essentially all of the acetone within the crystal form was removed by storing the crystals under vacuum for 3,4 days. By employing these techniques, gram quantities of enantiomeric gossypol were prepared in high chemical and optical purity. Based on measured and reported optical rotations, the optical purity of samples prepared by crystallization was greater than the optical purity of samples prepared by chromatographic separation of gossypol-amine diastereomers. The principal limitation of crystallization as a preparative method is the need to determine the chirality and purity of each product crystal. Nevertheless, the method competes favorably with preparative-scale chromatographic procedures. Chirality 15:486,493, 2003. Published 2003 Wiley-Liss, Inc. [source] | ||||||||||