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Average Recovery (average + recovery)
Selected AbstractsCapillary Zone Electrophoresis and Micellar Electrokinetic Capillary Chromatography for Determining Water-Soluble Vitamins in Commercial Capsules and TabletsJOURNAL OF FOOD SCIENCE, Issue 1 2001S-C. Su ABSTRACT: A rapid method was developed for simultaneously determining thiamine, riboflavin, pyridoxine, nicotinamide, nicotinic acid, and ascorbic acid. It was tested on 15 samples. The peaks of all components were cleanly separated with good resolution by capillary zone electrophoresis (CZE) and micellar electrokinetic chromatography (MECC). CZE was performed with 0.02 M borate buffer, and MECC was performed with 4% acetonitrile in 0.02 M borate/phosphate buffer containing 0.1 M sodium dodecyl sulfate. Average recoveries for all components were 80.3% to 103.7% with coefficients of variation being less than 5%. Thiamine, nicotinic acid, and pyridoxine contents were consistent with those labeled on the packages, but nicotinamide, riboflavin, and ascorbic acid contents of some samples were less. [source] Separation and determination of five major opium alkaloids with mixed mode of hydrophilic/cation-exchange monolith by pressurized capillary electrochromatographyJOURNAL OF SEPARATION SCIENCE, JSS, Issue 17 2007Xucong Lin Abstract A method for the separation and determination of five major opium alkaloids (narcotine, papaverine, thebaine, codeine, and morphine) in pericarpium papaveris by pressurized CEC (pCEC) with monolithic column has been developed. Under the optimum condition, linear calibration ranges of narcotine, papaverine, thebaine, codeine, and morphine were obtained as 2,85, 2,85, 5,75, 10,65, and 10,65 ,g/mL, respectively. LODs of these analytes were 1.5,6.0 ,g/mL. The RSD (n = 7) of the migration time and peak area were 1.94,5.24 and 4.05,8.21%, respectively. The proposed method was successfully applied to the analysis of pericarpium papaveris samples. Average recoveries of 79.0,95.9% at different fortified levels of alkaloids were achieved with RSD less than 4.6%. Meanwhile, the mechanism of the separation of the alkaloids on the monolithic column was also discussed. The result showed that the separation of alkaloids was mainly based on the mixed mode of hydrophilic interaction (HI) and cation exchange. [source] Application of programmable temperature vaporisation injection with resistive heating-gas chromatography flame photometric detection for the determination of organophosphorus pesticidesJOURNAL OF SEPARATION SCIENCE, JSS, Issue 1 2006Katan Patel Abstract The combination of a programmable temperature vaporisation (PTV) injector with resistive heating GC (RH-GC), a form of fast GC, has been applied to the analysis of organophosphorus (OP) pesticides. The PTV injector was optimised in the ,at-once' solvent vent mode for the injection of ethyl acetate (10,40 ,L) or ACN (10 ,L). The short RH-GC column (5 m×0.25 mm ID) with fast temperature ramps (up to 153°C/min) allowed the separation of a total of 20 OP pesticides in less than 6 min. Average recoveries between 67 and 119% were obtained for pesticides spiked at 0.01 mg/kg into apple and pear matrix. Extraction of orange juice with ACN provided higher recoveries (92,104%) for methamidophos, acephate and omethoate compared to ethyl acetate (62,73%). Results for analysis of OP pesticides in samples containing incurred residues were in good agreement with those obtained using GC-MS. The overall method was rapid, allowing 20 samples to be analysed in 4 h. British Crown Copyright © 2005 Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim [source] Development of a sensitivity-improved immunoassay for the determination of carbaryl in food samplesJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 7 2010Tingting Dong Abstract BACKGROUND: With the aim of developing a highly sensitive immunoassay for carbaryl, a hapten which had high similarity to carbaryl was synthesised using a safer and more practical approach. After it was conjugated to horseradish peroxidase, direct competitive heterologous enzyme-linked immunosorbent assay (CD-ELISA) was optimised and characterised. The assay performance conditions were investigated in details. Enhanced chemiluminescence ELISA (ECL-ELISA) was also used in preliminary studies. RESULTS: The assay obtained an IC50 value (the concentration causing 50% inhibition) of 2 µg kg,1, which was 12-fold more sensitive than previous results of homologous CD-ELISA. In ECL-ELISA, the IC50 was further decreased 10-fold to 0.2 µg kg,1. The CD-ELISA developed was applicable for broad conditions, and could be applied on various food samples with a more convenient pre-treatment. Average recoveries were in a range of 88.3,101.7%. The results correlated well with those obtained using high-performance liquid chromatography (HPLC) analysis (R2 = 0.989). CONCLUSION: The ELISA developed was a great improvement in the determination of carbaryl, showing that the immunoassay developed was a simple, rapid and efficient method that was reliable for the detection of carbaryl and suitable for rapid quantitative or qualitative determination in food samples. Copyright © 2010 Society of Chemical Industry [source] Simultaneous determination of five aristolochic acids and two aristololactams in Aristolochia plants by high-performance liquid chromatographyBIOMEDICAL CHROMATOGRAPHY, Issue 4 2006Cuiying Zhang Abstract An HPLC method was developed for the simultaneous determination of five aristolochic acids (AAs) and two aristololactams (ALs) in the following six Chinese drugs derived from Aristolochia species. Samples were analyzed on a C18 column with acetonitrile and 3.7 mm phosphoric acid buffer gradient elution, detected at 260 nm. Assay was linear over the range (µg/mL) 0.386,38.6 for aristolochic acid Va, 0.632,63.2 for aristolochic acid IVa, 0.200,20.0 for 9-hydroxy aristolochic acid I, 0.352,35.2 for aristololactam II, 0.296,29.6 for aristolochic acid II, 0.274,27.4 for aristololactam I and 3.12,312 for aristolochic acid I. Average recoveries (%) of samples were 102.0, 95.9, 99.2, 102.2, 97.2, 97.1 and 97.8 for these seven constituents, respectively. The detection limit and retention time for the seven constituents ranged from 10.0 to 15.8 ng/mL and from 12 to 21 min. As a result of drug determination, contents (in mg/g) were as follows: AA-I, 0.69,1.77; AA-II, 0.02,0.18; 9-OH AA-I, 0.04,0.12; AA-IVa, 0.76,3.36; AA-Va, 0.04,0.31; AL-I, 0.07,0.36; and AL-II, 0.01,0.09 in Madouling; AA-I, 0.03,0.41; AA-II, 0.01,0.11; 9-OH AA-I, 0.00,0.60; AA-IVa, 0.00,0.77; AA-Va, 0.00,0.14; and AL-I, 0.00,0.04 in Tianxianteng; AA-I, 1.19,4.71; and AA-II, 0.24,1.69 in Qingmuxiang; AA-I, 2.79,5.48; AA-II, 1.06,1.86; 9-OH AA-I, 0.01,0.09; AA-IVa, 0.38,0.69; AA-Va, 0.00,0.61; AL-I, 0.00,0.02; and AL-II, 0.00,0.02 in Bei-madouling-gen; AA-I, 0.64,4.23; AA-II, 0.06,0.40; and AA-IVa, 0.08,0.25; in Guangfangji; and AA-I, 1.88,9.72; AA-II, 0.26,1.88; and AA-IVa, 0.09,0.52 in Guanmutong. The other constituents were not detected in Tianxianteng, Qingmuxiang, Guangfangji and Guanmutong. Copyright © 2005 John Wiley & Sons, Ltd. [source] Development and validation of a HPLC method for determination of levonorgestrel and quinestrol in rat plasmaBIOMEDICAL CHROMATOGRAPHY, Issue 7 2010Tao Tang Abstract Levonorgestrel and quinestrol, commonly known as EP-1, has long been used in the control of wild rodents. Up to the present time, however, no method for simultaneous quantification of levonorgestrel and quinestrol in rat plasma has been reported. In the present study, a sensitive reverse-phase high-performance liquid chromatography with ultraviolet detection (RP-HPLC-UV) method for quantification of levonorgestrel and quinestrol in rat plasma has been developed. It uses a Kromasil ODS C18 column and acetonitrile-0.1% formic acid (85,:,15, v/v) mobile phase at ambient temperature. The plasma sample was prepared by hexane,isoamyl alcohol extraction (90,:,10, v/v). The flow rate and detection wavelength were 1.0,mL/min and 230,nm. The correlation coefficients were greater than 0.9995 within 0.08,50,,g/mL for levonorgestrel and 0.12,50,,g/mL for quinestrol, and the limits of detection were 0.02 and 0.05,,g/mL for levonorgestrel and quinestrol, respectively. Average recovery ranged from 92.5 to 96.3% and inter-day RSDs were less than 7.56%. This method can be applied to the further pharmacokinetic study of levonorgestrel and quinestrol in rat plasma. Copyright © 2009 John Wiley & Sons, Ltd. [source] A sweeping-micellar electrokinetic chromatography method for direct detection of some aromatic amines in water samplesELECTROPHORESIS, Issue 4 2008Jianhua Zhang Abstract A simple and rapid sweeping method for the online improvement of detection limit of some aromatic amines has been developed in this work. The optimum sweeping and separation conditions for 4-methylaniline, 3,4-dichloroaniline, 4-chloroaniline, and 4-aminophenyl were investigated in detail. Under the optimum conditions, the detection limits of these four aromatic amines ranged from 5.4×10,10 to 4.6×10,8,mol/L (S/N,=,3), which was about 80,1090-folds lower than those of conventional sample injections. Linear response range were in the range of 2.5×10,8,2.0×10,6,mol/L with the correlation coefficient between 0.9965 and 0.9994. Baseline separation was achieved within 10,min. After validation, the developed method was applied to determine 4-methylaniline, 3,4-dichloroaniline, 4-chloroaniline, and 4-aminophenyl in river water sample with average recoveries of 79.6,88.7%. [source] Simultaneous determination of substrate and product in the process of preparation of valienamine by capillary zone electrophoresisJOURNAL OF SEPARATION SCIENCE, JSS, Issue 13 2010Xiao-Dong Wei Abstract A simple and rapid CZE method was established for the simultaneous determination of valienamine, acarbose and validamycin A, using a 20-kV CZE with the detection wavelength of 193,nm and 50,mM phosphoric acid,20,mM Tris (pH 5.3) as a running buffer. The calibration curves of valienamine, acarbose, and validamycin A showed a good linear relationship at a concentration range of 5,1000,,g/mL. The detection limits of valienamine, acarbose, and validamycin A were 0.3, 0.6, and 0.6,,g/mL, respectively, and the average recoveries of each of the above were 99.9, 99.5, and 100.3%. The method has been successfully applied for simultaneous determination of substrate and product in the process of preparation of valienamine. [source] Capillary high performance liquid chromatography coupled with electrospray ionization mass spectrometry for rapid analysis of pinane monoterpene glycosides in Cortex MoutanJOURNAL OF SEPARATION SCIENCE, JSS, Issue 1 2008Yue Song Abstract In this study, a rapid and reliable assay has been developed for quantification of pinane monoterpene glycosides in Cortex Moutan; it is based on capillary high performance liquid chromatography coupled with electrospray ionization mass spectrometry (capillary HPLC,ESI MS). This method utilizes capillary HPLC for the separation of seven pinane monoterpene glycosides in a methanol extract of the botanical sample followed by negative ion electrospray ionization and single ion monitoring (SIM). The compounds of interest in the sample were unambiguously identified on the basis of information about retention time and quasi-molecular ions ([M,H],) or adduct ions ([M+HCOO],). Validation parameters of the method were established. The linearity range was 1.01,105.5 ,g/mL with the square of correlation coefficients lying in the range of 0.9965,0.9997, limits of detection were on the fmol level, the average recoveries varied between 91.8 and 101.0%, and good precision values (RSD, 1.2,4.91%) for peak area were obtained. After validation, the applicability of the method for determination of these pinane monoterpene glycosides in Cortex Moutan has been demonstrated. [source] Determination of ibuprofen in pharmaceutical formulations using time-resolved terbium-sensitized luminescenceLUMINESCENCE: THE JOURNAL OF BIOLOGICAL AND CHEMICAL LUMINESCENCE, Issue 4 2007Salma M. Z. Al-Kindy Abstract A sensitive and specific luminescence method for the determination of ibuprofen (IB) in pharmaceutical formulations in aqueous solution is described. The method is based on the luminescence sensitization of terbium (Tb3+) by formation of ternary complex with IB in the presence of tri- n -octylphosphine oxide (TOPO) and Tween-20 as surfactant. The luminescence signal for Tb,IB,TOPO is monitored at ,ex = 229 nm and ,em = 545 nm. Optimum conditions for the formation of the complex in aqueous system, were 16 mmol/L TRIS buffer, pH 5.7, TOPO 200 µmol/L and 15 µmol/L of Tb3+, which allows for the determination of 9.7 × 10,7 , 9.7 × 10,6 mol/L IB with a detection limit of 1.2 × 10,7 mol/L. The relative standard deviations of the method were <1.4%, indicating excellent reproducibility. The proposed method was successfully applied for the assays of IB in pharmaceutical formulations with average recoveries of 100.3,102.5%. Copyright © 2007 John Wiley & Sons, Ltd. [source] Determination and toxicokinetics comparison of ketamine and S(+)-ketamine in dog plasma by HPLC-MS methodBIOMEDICAL CHROMATOGRAPHY, Issue 3 2010Yu-xin Sheng Abstract ;A simple and reproducible method was developed for the quantification of ketamine and S(+)-ketamine in dog plasma using a high-performance liquid chromatography system coupled to a positive ion electrospray mass spectrometric analysis. Solid-phase extraction was used for extracting analytes from dog plasma samples. The analytes were separated on a Zorbax SB C18 column (100 × 2.1 mm, 3.5 ,m) with acetonitrile,formate buffer (10 mM ammonium formate and 0.3% formic acid) (17 : 83, v/v) as mobile phase at a flow-rate of 0.2 mL/min. Detection was operated under selected ion monitoring mode. [M + H]+ at m/z 238 for ketamine and S(+)-ketamine and [M + H]+ at m/z 180 for phenacetin (internal standard) were selected as detecting ions, respectively. The method was linear in the concentration range 51.6,2580 ng/mL. The intra- and inter-day precisions (RSD %) were within 11.3% and the assay accuracies ranged from 80.0 to 101.4%. Their average recoveries were greater than 91.1% at all test concentrations. The analytes were proved to be stable during all sample storage, preparation and analysis procedures. The method was successfully applied to the toxicokinetics study and comparison of ketamine and S (+)-ketamine following intravenous administration to dogs. Copyright © 2009 John Wiley & Sons, Ltd. [source] Voltammetric Sensor for Sodium Nitroprusside Determination in Biological Fluids Using Films of Poly- L -LysineELECTROANALYSIS, Issue 9 2007Claudece Pereira, Francisco Abstract Sodium nitroprusside (NP), a commercial vasodilator, can be pre-concentrated on vitreous carbon electrode modified by films of 97.5%: 2.5% poly- L -lysine (PLL): glutaraldehyde (GA). This coating gives acceptable anion exchange properties whilst giving the required improvement of adhesion to the glassy carbon electrode surface. Linear response range and detection limit on nitroprusside in B-R buffer pH,4.0, were 1×10,6 to 2×10,5 mol L,1 and 1×10,7 mol L,1, respectively. The repeatability of the proposed sensor, evaluated in term of relative standard deviation, was measured as 4.1% for 10 experiments. The voltammetric sensor was directly applied to determination of nitroprusside in human plasma and urine samples and the average recovery for these samples was around 95,97% without any pre treatment. [source] Preparation and Characteristics of Esculin-Imprinted PolymersHELVETICA CHIMICA ACTA, Issue 6 2007Guo-Song Wang Abstract Four molecularly imprinted polymers (MIPs) were prepared in MeOH with esculin (=6,7-dihydroxycoumarin 6-(, - D -glucopyranoside)=6-(, - D -glucopyranosyloxy)-7-hydroxy-2H -1-benzopyran-2-one) as the imprinted molecule, methacrylic acid (=2-methylprop-2-enoic acid; MAA), acrylamide (=prop-2-enamide; AM), 4-vinylpyridine (=4-ethenylpyridine; 4-VP), or 2-vinylpyridine (=2-ethenylpyridine; 2-VP) as the functional monomer, respectively, as well as ethylene glycol dimethacrylate (=2-methylprop-2-enoic acid ethane-1,2-diyl ester; EGDMA) as the cross-linking agent. The interaction between the template and the functional monomers was investigated by fluorescence and UV spectrophotometry, respectively, which revealed the presence of esculin/monomer complexes in the stoichiometric ratio 1,:,2 in the pre-polymerization mixture. The resultant polymers were studied in equilibrium binding experiments to evaluate the recognition ability and the binding capacity towards esculin. The results showed that MIP1, prepared with MAA as the functional monomer, exhibited advantageous characteristics of high binding capacity, optimal imprinting effect, and good selectivity towards esculin. The Scatchard analysis indicated that there are two types of binding sites in MIP1, and its binding parameters including the apparent maximum numbers of binding sites and the dissociation constants were calculated. Finally, by packing an SPE column (SPE=solid-phase extraction) with MIP1, the esculin was separated and enriched successfully by this sorbent from samples of Cortex fraxini, and the average recovery was up to 74.7%. [source] Silica-based monolithic column with evaporative light scattering detector for HPLC analysis of bacosides and apigenin in Bacopa monnieriJOURNAL OF SEPARATION SCIENCE, JSS, Issue 15-16 2009Pamita Bhandari Abstract A high performance liquid chromatographic method using a silica-based monolithic column coupled with evaporative light scattering detector (HPLC,ELSD) was developed and validated for simultaneous quantification of bacosides (bacoside A, bacopaside I, bacoside A3, bacopaside II, bacopaside X, bacopasaponin C) and apigenin in Bacopa monnieri. The chromatographic resolution was achieved on a Chromolith RP-18 (100×4.6 mm) column with acetonitrile/water (30:70) as mobile phase in isocratic elution at a flow rate of 0.7 mL/min. The drift tube temperature of the ELSD was set to 95°C, and the nitrogen flow rate was 2.0 SLM (standard liter per minute). The calibration curves revealed a good linear relationship (r2 >0.9988) within the test ranges. The detection limits (S/N = 3) and the quantification limits (S/N = 10) for the compounds were in the range of 0.54,6.06 and 1.61,18.78 ,g/mL, respectively. Satisfactory average recovery was observed in the range of 95.8,99.0%. The method showed good reproducibility for the quantification of these compounds in B. monnieri with intra- and inter-day precision of less than 0.69 and 0.67%, respectively. The validated method was successfully applied to quantify analytes in nine accessions of B. monnieri and thus provides a new basis for overall quality assessment of B. monnieri. [source] Extraction of pure lycopene from industrial tomato by-products in water using a new high-pressure processJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 14 2008Daniele Naviglio Abstract BACKGROUND: Lycopene, a precursor of ,-carotene with a well-known antioxidant activity, contained in many natural products such as tomato (Lycopersicon esculentum Mill.), watermelon, red pepper and papaya, is usually recovered from natural vegetal sources using organic solvents and a purification step. In this paper an innovative process for the extraction of pure lycopene from tomato waste in water that uses the Naviglio® extractor and water as extracting phase is presented. RESULTS: Lycopene was obtained in the all- trans form at a very high grade of purity, not less than 98% (w/w), with an average recovery of 14% (w/w). The availability of high-purity trans -lycopene allowed measurement of the molar absorption coefficient. An alternative procedure for high-performance liquid chromatographic analysis using a phenyl-hexyl silicone phase as inverse phase and a linear gradient in water and acetonitrile is also described. CONCLUSIONS: The use of water as extracting phase considerably reduces the cost of the entire process when compared with the commonly used solvent-based procedure or with the newer supercritical extraction process of lycopene from tomato waste. Lycopene, not soluble in water, was recovered in a quasi-crystalline solid form and purified by solid-phase extraction using a small amount of organic solvent. Copyright © 2008 Society of Chemical Industry This article was published online on September 15, 2008. Errors in Figures 2 - 4 were subsequently identified. The publishers wish to apologise for these errors. This notice is included in the online and print versions to indicate that both have been corrected [September 19, 2008] [source] Freezing equine semen: the effect of combinations of semen extenders and glycerol on post-thaw motilityAUSTRALIAN VETERINARY JOURNAL, Issue 7 2009J Scherzer Objective We evaluated combinations of two commercial semen extenders and three concentrations of glycerol to determine the combination that yielded the highest post-thaw sperm motility. Design A randomised 2 × 3 block design was used. Procedure Semen was collected from four stallions (6 collections per stallion). The sample was diluted with either a dried skim-milk glucose extender (EZ Mixin Original Formula) or a chemically defined, milk-free diluent (INRA 96), and each was used in combination with 2%, 3% or 4% glycerol in standard commercial freezing medium. Sperm motility was assessed by microscopy in fresh and post-thaw semen. Results There was a significant difference between the two extenders in the motility of spermatozoa after cryopreservation (48.9% for INRA 96; 38.6% for EZ Mixin OF; P < 0.0001). Glycerol at 4% in freezing medium yielded the highest post-thaw motility, significantly better than 2% (P < 0.05). Three of four stallions had significantly higher post-thaw motility using INRA 96 relative to EZ Mixin OF (P < 0.01), and two of four stallions had significantly higher post-thaw motility using 4% glycerol (P < 0.05). The combination of INRA 96 and 4% glycerol in freezing medium gave the highest average post-thaw motility of 51.5%. Conclusion In this study, INRA 96 combined with 4% glycerol yielded an average recovery of progressively motile sperm consistently above the 35% target. [source] A validated new method for nevirapine quantitation in human plasma via high-performance liquid chromatographyBIOMEDICAL CHROMATOGRAPHY, Issue 1 2006Courtney F. Silverthorn Abstract A fully validated and clinically relevant assay was developed for the assessment of nevirapine concentrations in neonate blood plasma samples. Solid-phase extraction with an acid,base wash series was used to prepare subject samples for analysis. Samples were separated by high performance liquid chromatography and detected at 280 nm on a C8 reverse-phase column in an isocratic mobile phase. The retention times of nevirapine and its internal standard were 5.0 and 6.9 min, respectively. The method was validated by assessment of accuracy and precision (statistical values <15%), specificity, and stability. The assay was linear in the range 25,10,000 ng[sol ]mL (r2 > 0.996) and the average recovery was 93% (n = 18). The lower limit of quantification (relative standard deviation <20%) was determined to be 25 ng[sol ]mL for 50 µL of plasma, allowing detection of as little as 1.25 ng of nevirapine in a sample. This value represents an increase in sensitivity of up to 30-fold over previously published methods. Copyright © 2005 John Wiley & Sons, Ltd. [source] Optimization of an enrichment process for circulating tumor cells from the blood of head and neck cancer patients through depletion of normal cellsBIOTECHNOLOGY & BIOENGINEERING, Issue 2 2009Liying Yang Abstract The optimization of a purely negative depletion, enrichment process for circulating tumor cells (CTCs) in the peripheral blood of head and neck cancer patients is presented. The enrichment process uses a red cell lysis step followed by immunomagnetic labeling, and subsequent depletion, of CD45 positive cells. A number of relevant variables are quantified, or attempted to be quantified, which control the performance of the enrichment process. Six different immunomagnetic labeling combinations were evaluated as well as the significant difference in performance with respect to the blood source: buffy coats purchased from the Red Cross, fresh, peripheral blood from normal donors, and fresh peripheral blood from human cancer patients. After optimization, the process is able to reduce the number of normal blood cells in a cancer patient's blood from 4.05,×,109 to 8.04,×,103 cells/mL and still recover, on average, 2.32 CTC per mL of blood. For all of the cancer patient blood samples tested in which CTC were detected (20 out of 26 patients) the average recovery of CTCs was 21.7 per mL of blood, with a range of 282 to 0.53 CTC. Since the initial number of CTC in a patient's blood is unknown, and most probably varies from patient to patient, the recovery of the CTC is unknown. However, spiking studies of a cancer cell line into normal blood, and subsequent enrichment using the optimized protocol indicated an average recovery of approximately 83%. Unlike a majority of other published studies, this study focused on quantifying as many factors as possible to facilitate both the optimization of the process as well as provide information for current and future performance comparisons. The authors are not aware any other reported study which has achieved the performance reported here (a 5.66 log10) in a purely negative enrichment mode of operation. Such a mode of operation of an enrichment process provides significant flexibility in that it has no bias with respect to what attributes define a CTC; thereby allowing the researcher or clinician to use any maker they choose to define whether the final, enrich product contains CTCs or other cell type relevant to the specific question (i.e., does the CTC have predominately epithelial or mesenchymal characteristics?). Biotechnol. Bioeng. 2009;102: 521,534. © 2008 Wiley Periodicals, Inc. [source] | |||||||||||||||||||||||||