Scale-up and Optimization of the Low-Temperature Inducible cspA Promoter System

1998 ◽  
Vol 14 (5) ◽  
pp. 714-721 ◽  
Author(s):  
J.A. Vasina ◽  
M.S. Peterson ◽  
F. Baneyx
Keyword(s):  
Low Temperature ◽  
Scale Up ◽  
Cspa Promoter ◽  
Promoter System

Application of the Continuous Rheoconversion Process (CRP) to Low Temperature HPDC-Part I: Microstructure

2006 ◽  
Vol 116-117 ◽  
pp. 402-405 ◽  
Author(s):  
Qin Yue Pan ◽  
Stuart Wiesner ◽  
Diran Apelian
Keyword(s):  
Low Temperature ◽  
Scale Up ◽  
Microstructural Characterization ◽  
Industrial Applications ◽  
Primary Phase ◽  
Heat Extraction ◽  
Initial Stage ◽  
Fraction Solid ◽  
Die Castings

The continuous rheoconversion process (CRP) is a novel slurry-on-demand process that was developed at MPI/WPI in 2002. The process is based on a passive liquid mixing technique in which the nucleation and growth of the primary phase are controlled using a specially designed “reactor”. The reactor provides heat extraction, copious nucleation, and forced convection during the initial stage of solidification, thus leading to the formation of globular structures. This paper presents our recent work on the scale-up of the CRP for industrial applications. Specifically, we demonstrate an important application of the CRP to low temperature (low fraction solid) HPDC. In Part I of this paper, we present salient results on microstructural characterization of CRP processed castings vs. conventional die castings.

scholarly journals Activation of Soluble Polysaccharides with 1-Cyano-4-Dimethylaminopyridine Tetrafluoroborate (CDAP) for Use in Protein–Polysaccharide Conjugate Vaccines and Immunological Reagents. III Optimization of CDAP Activation

Vaccines ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 777
Author(s):  
Andrew Lees ◽  
Jackson F. Barr ◽  
Samson Gebretnsae
Keyword(s):  
Reaction Time ◽  
Low Temperature ◽  
Scale Up ◽  
Optimal Time ◽  
Conjugate Vaccines ◽  
Maximal Activation ◽  
Optimum Reaction ◽  
Rapid Reaction ◽  
The Stability ◽  
High Level

CDAP (1-cyano-4-dimethylaminopyridine tetrafluoroborate) is employed in the synthesis of conjugate vaccines as a cyanylating reagent. In the published method, which used pH 9 activation at 20 °C (Vaccine, 14:190, 1996), the rapid reaction made the process difficult to control. Here, we describe optimizing CDAP activation using dextran as a model polysaccharide. CDAP stability and reactivity were determined as a function of time, pH and temperature. While the rate of dextran activation was slower at lower pH and temperature, it was balanced by the increased stability of CDAP, which left more reagent available for reaction. Whereas maximal activation took less than 2.5 min at pH 9 and 20 °C, it took 10–15 min at 0 °C. At pH 7 and 0 °C, the optimal time increased to >3 h to achieve a high level of activation. Many buffers interfered with CDAP activation, but DMAP could be used to preadjust the pH of polysaccharide solutions so that the pH only needed to be maintained. We found that the stability of the activated dextran was relatively independent of pH over the range of pH 1–9, with the level of activation decreased by 40–60% over 2 h. The use of low temperature and a less basic pH, with an optimum reaction time, requires less CDAP, improving activation levels while making the process more reliable and easier to scale up.

scholarly journals Highly Porous Graphitic Activated Carbons from Lignite via Microwave Pretreatment and Iron-Catalyzed Graphitization at Low-Temperature for Supercapacitor Electrode Materials

Processes ◽  
2019 ◽  
Vol 7 (5) ◽  
pp. 300 ◽  
Author(s):  
Dongdong Liu ◽  
Xiaoman Zhao ◽  
Rui Su ◽  
Zhengkai Hao ◽  
Boyin Jia ◽  
...  
Keyword(s):  
Low Temperature ◽  
Electrode Materials ◽  
Activated Carbons ◽  
Chemical Activation ◽  
Scale Up ◽  
Physical Activation ◽  
Supercapacitor Electrode ◽  
Microwave Pretreatment ◽  
Wide Range ◽  
Highly Porous

At present, the preparation of highly porous graphitic activated carbons (HPGACs) using the usual physical and chemical activation methods has met a bottleneck. In this study, HPGACs are directly synthesized from lignite at 900 °C. The whole process is completed by a microwave pretreatment, a graphitization conversion of the carbon framework at a low temperature using a small amount of FeCl3 (10–30 wt%), and a subsequent physical activation using CO2. Consequently, the dispersed and mobile iron species, in the absence of oxygen functional groups (removed during the microwave pretreatment), can greatly promote catalytic graphitization during pyrolysis, and, as an activating catalyst, can further facilitate the porosity development during activation. The as-obtained AC-2FeHLH-5-41.4(H) presents a low defect density, high purity, and specific surface area of 1852.43 m2 g−1, which is far greater than the AC-HLH-5-55.6(H) obtained solely by physical activation. AC-2FeHLH-5-41.4(H) as a supercapacitor electrode presents an excellent performance in the further electrochemical measurements. Such a convenient and practical method with low cost proves a scalable method to prepare HPGACs from a wide range of coal/biomass materials for industrial scale-up and applications.

Efficient and cost-effective graphene on silicon solar cells prepared by spray coating

RSC Advances ◽  
2014 ◽  
Vol 4 (98) ◽  
pp. 55300-55304 ◽  
Author(s):  
Kejia Jiao ◽  
DangWen Zhang ◽  
Yunfa Chen
Keyword(s):  
Solar Cells ◽  
Low Temperature ◽  
Mass Production ◽  
Scale Up ◽  
Spray Coating ◽  
Cost Effective ◽  
Silicon Solar Cells ◽  
Si Solar Cells

A facile method – graphene on silicon (G/Si) solar cells prepared by spray coating – is developed. The efficiency of spray-coated G/Si solar cells can reach 4.41%, comparable to that of conventional CVD-G/Si solar cells. This approach is done in air at low temperature, and is easy to scale up, making it appealing for the mass production of efficient and cost-effective G/Si solar cells.

Further Development of Iodine Immobilization Technique by Low Temperature Vitrification With BiPbO2I

2009 ◽  
Author(s):  
Atsushi Mukunoki ◽  
Tamotsu Chiba ◽  
Yasuhiro Suzuki ◽  
Kenji Yamaguchi ◽  
Tomofumi Sakuragi ◽  
...  
Keyword(s):  
Low Temperature ◽  
Photoelectron Spectroscopy ◽  
Structural Information ◽  
Scale Up ◽  
Melting Furnace ◽  
Analytical Techniques ◽  
Nuclear Magnetic Resonance Analysis ◽  
X Ray ◽  
Resonance Analysis ◽  
Chemical Conditions

The authors describe progress in the development of low temperature vitrification with BiPbO2I (BPI) as a promising immobilization technique by which Iodine-129 is recovered by BiPbO2NO3 to form BPI, and then solidified into a lead-boron-zinc glass matrix (PbO-B2O3-ZnO) using a low temperature vitrification process. The microscopic structure of BPI glass was analyzed by various analytical techniques, such as XRD (X-ray diffraction), NMR (nuclear magnetic resonance analysis), and XPS (X-ray photoelectron spectroscopy), using several types of glass samples. The results obtained provide structural information on key elements in BPI glass and can be applied for modeling the structure of the BPI glass, simulated by molecular dynamics. The previous work suggested that the leaching behavior of iodine from BPI glass depended upon the chemical conditions of the solution. Further leaching tests using solutions under varying conditions were carried out in order to predict mechanisms of iodine leaching. Normalized elemental mass loss values of iodine in simulated seawater and bentonite pore water are almost the same as those of boron, showing that iodine dissolves congruently with BPI glass, whereas iodine dissolves incongruently in Ca(OH)2 solutions of pH 9 and 11. To demonstrate the feasibility of the BPI vitrification process, recovery tests of iodine from spent iodine filters were conducted and a prototype melting furnace was developed for scale-up tests of glass sample. It was found that more than 95% of iodine can be recovered from the spent iodine filter and that the prototype furnace can produce approximately 0.5 liters of homogeneous glass.

A scale-up strategy for low-temperature methanol synthesis in a circulating slurry bubble reactor

2006 ◽  
Vol 61 (5) ◽  
pp. 1459-1469 ◽  
Author(s):  
Kai Zhang ◽  
Yulong Zhao
Keyword(s):  
Low Temperature ◽  
Methanol Synthesis ◽  
Scale Up

scholarly journals Extended −10 Motif Is Critical for Activity of the cspA Promoter but Does Not Contribute to Low-Temperature Transcription

2005 ◽  
Vol 187 (18) ◽  
pp. 6584-6589 ◽  
Author(s):  
Sangita Phadtare ◽  
Konstantin Severinov
Keyword(s):  
Low Temperature ◽  
Cold Shock ◽  
Cold Shock Protein ◽  
Mrna Stabilization ◽  
Cold Sensitive ◽  
Temperature Downshift ◽  
Cspa Promoter ◽  
High Level

ABSTRACT Bacterial promoters belonging to the extended −10 class contain a conserved TGn motif upstream of the −10 promoter consensus element. Open promoter complexes can be formed on some extended −10 Escherichia coli promoters at temperatures as low as 6°C, when complexes on most promoters are closed. The promoter of cspA, a gene that codes for the major cold shock protein CspA of E. coli, contains an extended −10 motif. CspA is dramatically induced upon temperature downshift from 37 to 15°C, and its cold shock induction has been attributed to transcription, translation, and mRNA stabilization effects. Here, we show that though the extended −10 motif is critical for high-level expression of cspA, it does not contribute to low-temperature expression. In fact, transcription from the wild-type cspA promoter is cold sensitive in vitro and in vivo. Thus, transcription appears to play little or no role in low-temperature induction of cspA expression.

Application of the Continuous Rheoconversion Process (CRPTM) to Low Temperature HPDC-Part II: Alloy Development & Validation

2006 ◽  
Vol 116-117 ◽  
pp. 64-67 ◽  
Author(s):  
Stuart Wiesner ◽  
Qin Yue Pan ◽  
Diran Apelian
Keyword(s):  
Low Temperature ◽  
Scale Up ◽  
Nucleation And Growth ◽  
Industrial Applications ◽  
Primary Phase ◽  
Heat Extraction ◽  
Alloy Development ◽  
On Demand ◽  
Initial Stage ◽  
Thermodynamic Simulations

The continuous rheoconversion process (CRPTM) is a novel slurry-on-demand process that was developed at MPI/WPI in 2002. The process is based on a passive liquid mixing technique in which the nucleation and growth of the primary phase are controlled using a specially designed “reactor”. The reactor provides heat extraction, copious nucleation, and forced convection during the initial stage of solidification, thus leading to the formation of globular structures. This paper presents our recent work on the scale-up of the CRPTM for industrial applications. In Part II of this paper, we present salient results on alloy optimization via thermodynamic simulations, as well as validation results obtained from industrial Beta trials.

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