470 research outputs found
Key factors of adopting energy management systems in building sector in Taiwan
It is no doubt the world is experiencing global warming and human emission causes distinct climate change. According to the analysis from International Energy Agency, the over consumed nature resources from power, industry, transport and building sectors are off the major factors reflecting on the essential greenhouse gases to life. As moving onto the smart technology and smart grid development, recent studies indicate that using the advanced energy management systems is critical to improve power efficiency, energy saving, and reduce greenhouse gas emission. This study relies on a systematic literature review and expert opinion to identify the critical factors of adoption building energy management system. Finally, a framework is presented to evaluate the introduction of energy management systems in the construction field in order to achieve zero carbon ready buildings
A circular elastic cylinder under its own weight
AbstractAn exact analysis of deformation and stress field in a finite circular elastic cylinder under its own weight is presented, with emphasis on the end effect. The problem is formulated on the basis of the state space formalism for axisymmetric deformation of a transversely isotropic body. Upon delineating the Hamiltonian characteristics of the formulation, a rigorous solution which satisfies the end conditions is determined by using eigenfunction expansion. The results show that the end effect is significant but confined to a local region near the base where the displacement and stress distributions are remarkably different from those according to the simplified solution that gives a uniaxial stress state. It is more pronounced in the cylinder with the bottom plane being perfectly bonded than in smooth contact with a rigid base
Synthesis of CuInSe2 thin films from electrodeposited Cu11In9 precursors by two-step annealing
In this study, copper indium selenide (CIS) films were synthesized from electrodeposited Cu-In-Se precursors by two-step annealing. The agglomeration phenomenon of the electrodeposited In layer usually occurred on the Cu surface. A thermal process was adopted to turn Cu-In precursors into uniform Cu11In9 binary compounds. After deposition of the Se layer, annealing was employed to form chalcopyrite CIS. However, synthesis of CIS from Cu11In9 requires sufficient thermal energy. Annealing temperature and time were investigated to grow high quality CIS film. Various electrodeposition conditions were investigated to achieve the proper atomic ratio of CIS. The properties of the CIS films were characterized by scanning electron microscopy (SEM), X-ray Diffraction (XRD), and Raman spectra
Critical Stressors Affecting Work Exhaustion of IS Employees in SMEs
The symptoms of stress are becoming more diversified in the IT labor market. IS employees need help in learning how to manage stress so as to reduce the strain in their work-life. The stress issue is also crucial to organizations through controlling stressors to reduce the levels of stress for maintaining better job performance. The purpose of this research is to study the effects of stressors and situational moderators on IS employees’ work exhaustion in the context of small- and medium-sized enterprises (SMEs). In line with the transaction-based model of stress, this research constructs a hypothesized model for testing and verification. Through the empirical survey on the IS employees in SMEs, the results are expected to fill the knowledge gap for IS workplace stress research and to provide references to the practice and the government for managing SMEs’ e-business implementation
Therapeutic protein expression platform of microbial system
A number of expression systems have been developed for the production of pharmaceutical products. Pichia pastoris and Escherichia coli expression system operate in our lab and express antibody fragment (scFv), cytokine, protein base adjuvant and vaccine and process enzyme. The expression platform are consisted of three part, first is strain generation , the second is fermentation process development in 250 ml fermentor and the last is process scale-up to 5 litter fermentor.
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Engineering of Escherichia coli protein expression process development
It almost 30% protein drugs are expression by Escherichia coli, because of rapid growth and high production yield. We have developed E.coli base system for recombinant protein expression, scFv, Fab and vaccine. In this study we introduce example about process development for nutrient components selection. Shaker flasks were used for different nitrogen and carbon components screening by DoE. Seven media formulations for E. coli fermentation were used in this study. By changing nitrogen and carbon source ratio, product titer of target protein could be optimized, at least 1.4 folds increased. The best result from shaker flask was used in 250 mL parallel fermenter and pH, dissolved oxygen, feeding/induction strategy were evaluated. The processes from seed culture to harvest only require 64 hours. The optimized time was reduced to 32 hours. The result showed that both target protein expression and cell density value were comparable, but the total process time was significantly reduced by half
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The microbial antibodies secretion expression platform with scale down fermentors
Therapeutic antibodies have become one of the most effective therapeutics for human diseases such as cancer, inflammation and viral infection. The production of antibody-based drugs using microbial expression systems is more cost effective with ease of gene manipulation compared to mammalian expression systems. In our team, antibody fragments (ex: BsAb, scFv and Fab) were produced from methylotrophic yeast Pichia pastoris secretion expression system with the AOX1 as driven promoter or E. coli secretion expression system. To achieve high production yield for both system, we investigated fermentation parameter such as base medium, induction medium, induction condition, feeding strategy and pH. For the 250 ml fermentor Pichia system, the nitrogen have been add into glycerol fed medium and/or methanol induction medium and also compared base-medium, buffered glycerol-complex medium (BMGY) and basal salt medium (BS). The highest scFv production was yielded from the basal salt medium as base medium, glycerol fed medium plus nitrogen and multiple carbon source methanol induction medium. This process can yielded over 500 mg/L scFv. After scale-up from 250 ml fermentor to 5L fermentor, the methanol fed-back control system also applied on the 5 L fermentor, can achieve 1.7 g/L scFv in 5 days. The E. coli expression process has passed through screening for high production yield clones in 2 ml deep-well then confirmed by using 250 ml flask scale. Feeding medium, DO, pH etc, parameters were investigated by parallel 250 ml-fermenter. The parameters from 250 ml fermentor were validated by using 5 L fermenter. Under this scale-up procedure, the antibody Fab was 100 folds production yield, production deep well stage at 1 mg/L, production from 250 ml fermentor stage is 50-100 mg/L and production 5 L fermentor stage is over 35-90 mg/L. Although different antibodies will result in different production yield, building a reliable platform to predict production yield from antibody cell clones under deep well and shake flask stage serves a good scale-down model for future scale-up prediction
Gram Level scFv expression platform of Pichia pastoris
The methylotrophic yeast Pichia pastoris secretion expression system has been developed for the antibody fragments (scFv) production platform. The platform includes three technology platforms, the first one is strain generation, the second is fermentation process development in 250 ml fermentor and the last is process scale up to 5 L. A recombinant scFv went through clone generation, include signal peptide tool box, normally yield 2.5 mg/L titer in deep well. Through the fermentation process development of induction medium composition and feeding strategy by Eppendorf Dasgip parallel 250 ml mini fermentor. During induction step, feeding 100% methanol as induction medium can only produce less than 50 mg/L scFv while feeding methanol-sorbitol mixture can significant increase the production yield to 306 mg/L in five days, about 6-folds increase in productivity. With the supply of additional nitrogen source during glycerol feeding step or at induction step, higher scFv production with 510 mg/L can be achieved. Thus, following the medium composition optimization, the production titer was improved 10 folds in 250 ml mini-fermentor stage. Moreover, when we switched the induction medium feeding strategy from DO-stat to the stepwise feeding, the titer increased form 510 mg/L to ~1000 mg/L and yielded another 2- folds improvement. During medium composition and feeding strategy optimization at 250 ml mini fermentor scale, the production titer could increase 20 folds. Overall, the production titer increased 400 folds from cell line generation to 250 ml fermentation parameter optimization. Furthermore, the process parameter can be scale-up to 5 L fernentor achieving \u3e 1 g/L. Recent progress to include BIP in the expression vector gave at least 2 fold improvement in scFv titer in shake flask, the new clone will be optimized in our established 250 ml and 5 L fermentation platform.
Please click Additional Files below to see the full abstract
Gram level scFv expression platform of Phichi pastoris
The methylotrophic yeast Pichia pastoris secretion expression system has been developed for the antibody fragments (scFv) production platform. The platform includes three technology platforms, the first one is strain generation, the second is fermentation process development in 250 ml fermentor and the last is process scale up to 5 L. A recombinant scFv went through clone generation, include signal peptide tool box, normally yield 2.5 mg/L titer in deep well. Through the fermentation process development of induction medium composition and feeding strategy by Eppendorf Dasgip parallel 250 ml mini fermentor. During induction step, feeding 100% methanol as induction medium can only produce less than 50 mg/L scFv while feeding methanol-sorbitol mixture can significant increase the production yield to 306 mg/L in five days, about 6-folds increase in productivity. With the supply of additional nitrogen source during glycerol feeding step or at induction step, higher scFv production with 510 mg/L can be achieved. Thus, following the medium composition optimization, the production titer was improved 10 folds in 250 ml mini-fermentor stage. Moreover, when we switched the induction medium feeding strategy from DO-stat to the stepwise feeding, the titer increased form 510 mg/L to ~1000 mg/L and yielded another 2- folds improvement. During medium composition and feeding strategy optimization at 250 ml mini fermentor scale, the production titer could increase 20 folds. Overall, the production titer increased 400 folds from cell line generation to 250 ml fermentation parameter optimization. Furthermore, the process parameter can be scale-up to 5 L fernentor achieving \u3e 1 g/L. Recent progress to include BIP in the expression vector gave at least 2 fold improvement in scFv titer in shake flask, the new clone will be optimized in our established 250 ml and 5 L fermentation platform
Please click Additional Files below to see the full abstract
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