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991.
Heterogeneous nuclear ribonucleoprotein K is associated with poor prognosis and regulates proliferation and apoptosis in bladder cancer 下载免费PDF全文
992.
A practical approach in bioreactor scale‐up and process transfer using a combination of constant P/V and vvm as the criterion 下载免费PDF全文
Sen Xu Linda Hoshan Rubin Jiang Balrina Gupta Eric Brodean Kristin O'Neill T. Craig Seamans John Bowers Hao Chen 《Biotechnology progress》2017,33(4):1146-1159
Bioreactor scale‐up is a critical step in the production of therapeutic proteins such as monoclonal antibodies (MAbs). With the scale‐up criterion such as similar power input per volume or O2 volumetric mass transfer coefficient ( ), adequate oxygen supply and cell growth can be largely achieved. However, CO2 stripping in the growth phase is often inadequate. This could cascade down to increased base addition and osmolality, as well as residual lactate increase and compromised production and product quality. Here we describe a practical approach in bioreactor scale‐up and process transfer, where bioreactor information may be limited. We evaluated the sparger and (CO2 volumetric mass transfer coefficient) from a range of bioreactor scales (3–2,000 L) with different spargers. Results demonstrated that for oxygen is not an issue when scaling from small‐scale to large‐scale bioreactors at the same gas flow rate per reactor volume (vvm). Results also showed that sparging CO2 stripping, , is dominated by the gas throughput. As a result, a combination of a minimum constant vvm air or N2 flow with a similar specific power was used as the general scale‐up criterion. An equation was developed to determine the minimum vvm required for removing CO2 produced from cell respiration. We demonstrated the effectiveness of using such scale‐up criterion with five MAb projects exhibiting different cell growth and metabolic characteristics, scaled from 3 to 2,000 L bioreactors across four sites. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:1146–1159, 2017 相似文献
993.
Triperylene Hexaimides Based All‐Small‐Molecule Solar Cells with an Efficiency over 6% and Open Circuit Voltage of 1.04 V 下载免费PDF全文
994.
Spatial Charge Storage within Honeycomb‐Carbon Frameworks for Ultrafast Supercapacitors with High Energy and Power Densities 下载免费PDF全文
Carbon‐based supercapacitors store charge through the adsorption of electrolyte ions onto the carbon surface. Therefore, it would be more attractive for the enhanced charge storage if the locations for storing charge can be extended from carbon surface to space. Here, a novel spatial charge storage mechanism based on counterion effect from Fe(CN)63? ions bridged by oxygen groups and confined into honeycomb‐carbon frameworks is presented, which can provide additionally spatial charge storage for electrical double‐layer capacitances in a negative potential region and pseudocapacitances from Fe(CN)63?/Fe(CN)64? in a positive potential region. More importantly, an ultrafast supercapacitor based on this novelty carbon can be charged/discharged within 0.7 s to deliver both high specific energy of 15 W h kg?1 and ultrahigh specific power of 79.1 kW kg?1 in 1 m Na2SO4 electrolyte, much higher than those of previously reported asymmetric supercapacitors in aqueous electrolytes, as well as excellent cycling stability. These features suggest a new generation of ultrafast asymmetric supercapacitors as novel high‐performance energy storage devices. 相似文献
995.
A new linear potentiometric titration method for the determination of deacetylation degree of chitosan 总被引:2,自引:0,他引:2
The degree of deacetylation (DD) is one of the most important properties of chitosan. Therefore, a simple, rapid and reliable method for the determination of DD of chitosan is essential. In this report, two new potentiometric titration functions are derived for the determination of DD of chitosan. The effects of the precipitation and the errors induced in pH measurement are discussed in detail. To make this method more simple and reliable, two universal pH regions for the accurate plotting of different DD chitosan samples are proposed for the new potentiometric titration functions. The DD values of three chitosan samples obtained with this new method show good agreement with those yielded from elemental analysis and 1H-NMR. 相似文献
996.
997.
Mutations in the homologous ZDS1 and ZDS2 genes affect cell cycle progression. 总被引:1,自引:2,他引:1 下载免费PDF全文
Y Yu Y W Jiang R J Wellinger K Carlson J M Roberts D J Stillman 《Molecular and cellular biology》1996,16(10):5254-5263
998.
Jiang H Wang Y Yu XQ Zhu Y Kanost M 《Insect biochemistry and molecular biology》2003,33(10):1049-1060
Phenoloxidase (PO) is a key enzyme implicated in several defense mechanisms in insects and crustaceans. It is converted from prophenoloxidase (proPO) through limited proteolysis by prophenoloxidase-activating proteinase (PAP). We previously isolated PAP-1 from integument and PAP-2 from hemolymph of the tobacco hornworm, Manduca sexta. Here, we report the purification, characterization, and regulation of PAP-3 from the hemolymph. Similar to M. sexta PAP-2, PAP-3 consists of two amino-terminal clip domains followed by a carboxyl-terminal catalytic domain, whereas PAP-1 contains only one clip domain at its amino-terminus. Purified PAP-3 cleaved proPO at Arg51 and generated a low level of PO activity. However, the enzyme efficiently activated proPO when M. sexta serine proteinase homolog-1 and -2 were present. These proteinase-like proteins associate with immulectin-2, a pattern-recognition receptor for lipopolysaccharide. M. sexta PAP-3 was inhibited by recombinant serpin-1J, which formed an SDS-stable complex with the enzyme. PAP-3 mRNA was detected at a low level in the fat body or hemocytes of naive larvae, but was elevated in insects that had been challenged with bacteria. These data, along with our previous results on PAP-1 and PAP-2, indicate that proPO activation by PAPs is a tightly regulated process. Individual PAPs could play different roles during immune responses and developmental processes. 相似文献
999.
Interaction with Tap42 is required for the essential function of Sit4 and type 2A phosphatases 下载免费PDF全文
In Saccharomyces cerevisiae, Pph21 and Pph22 are the two catalytic subunits of type 2A phosphatase (PP2Ac), and Sit4 is a major form of 2A-like phosphatase. The function of these phosphatases requires their association with different regulatory subunits. In addition to the conventional regulatory subunits, namely, the A and B subunits for Pph21/22 and the Sap proteins for Sit4, these phosphatases have been found to associate with a protein termed Tap42. In this study, we demonstrated that Sit4 and PP2Ac interact with Tap42 via an N-terminal domain that is conserved in all type 2A and 2A-like phosphatases. We found that the Sit4 phosphatase in the sit4-102 strain contains a reverse-of-charge amino acid substitution within its Tap42 binding domain and is defective for formation of the Tap42-Sit4 complex. Our results suggest that the interaction with Tap42 is required for the activity as well as for the essential function of Sit4 and PP2Ac. In addition, we showed that Tap42 is able to interact with two other 2A-like phosphatases, Pph3 and Ppg1. 相似文献