Effect of fermentation parameters such as c/N ratio, specific growth rate, phosphate limitation, and plasmid instability on enhancing isoprene production is the focus of the current study. Isoprene productivity in the...
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Effect of fermentation parameters such as c/N ratio, specific growth rate, phosphate limitation, and plasmid instability on enhancing isoprene production is the focus of the current study. Isoprene productivity in the recombinant Escherichia coli K12_MVA strain showed a bell-shaped relationship with specific growth rate in bioreactor studies with isoprene volumetric productivity peaking at 0.35/h. This behavior was depicted by a production inhibition kinetic model which envisaged a serious competition between the cellular growth, acetic acid production, and isoprene biosynthesis. The model equation derived showed a reasonable fit with the experimental values. Judicious control of the growth rates and acetate accumulation by optimizing c/N ratio, phosphate concentration, and intermittent feeding strategy resulted in maximizing the carbon flux towards isoprene. Plasmid instability caused by metabolic burden posed by the presence of dual plasmids on the bacteria was simulated using first-order degradation kinetics. The experimental plasmid loss trend was in accordance with the model simulated trend, where higher plasmid loss correlated with higher specific growth rates. Modulating the growth rate, acetate accumulation, and plasmid instability resulted in achieving maximum isoprene volumetric productivity of 1.125 g/l/h with 46.67% of carbon flux towards isoprene and a isoprene titre of 18 g/l in 16 h fermentation run.
Several leaves and shoot spot symptoms were observed on tomato (Lycopersicon esculentum Mill) plants at Zubair and Safwan farms in Basrah, Iraq. The symptomatic plant parts were collected from different varieties of t...
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Several leaves and shoot spot symptoms were observed on tomato (Lycopersicon esculentum Mill) plants at Zubair and Safwan farms in Basrah, Iraq. The symptomatic plant parts were collected from different varieties of tomato. The fungal pathogens were first isolated on PDA medium followed by a diagnosis procedure of the relevant fungi conducting phenotypiccharacterization and microscopic featuring. A molecular identification was applied by polymerase chain reaction technology using internal transcribed spacer sequences. All along an investigation on cladosporium species, three species including c. cladosporioides, c. oxysporum, and c. uredinicola were identified and recorded as new potential pathogen for the first time in Iraq causing leaf spot and lesion of tomato plant. Pathogenicity examination of each isolated pathogens was performed against of tomato plant. The importance of the current research is to investigate and identify the fungal pathogens of tomato plants to find the best protocols to restrict their growth and damage.
We report a novel fusion of microfluidics and light-field microscopy, to achieve high-speed 4D (space + time) imaging of moving c. elegans on a chip. Our approach combines automaticchip-based worm loading/ compartmen...
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We report a novel fusion of microfluidics and light-field microscopy, to achieve high-speed 4D (space + time) imaging of moving c. elegans on a chip. Our approach combines automaticchip-based worm loading/ compartmentalization/flushing/reloading with instantaneous deep-learning light-field imaging of behaving worm. Taken together, we realized intoto image-based screening of wild-type and uncoordinated-type worms at a volumetric imaging rate of 33 Hz, with sustained observation of 1 worm per minute and totally 42 worms per hour. Through four-dimensionally visualizing the dynamics of all the worms at an ultra-high throughput of 84000 image volumes in an hour, we can quantitatively analyze their behaviors as well as the neural activities, and correlate the phenotypes with the neuron functions. The different types of worms can be readily identified as a result of the high-throughput activity mapping. Our approach shows great potential for various lab-on-a-chip biological studies, such as high-throughput embryo sorting and cell growth assays.
The kinematic viscosity of Fe-Mn-c melts is measured with Mn contents of 5.0, 7.5, 10.0, 12.0, 15.0, 17.5, 20.0, and 25.0 wt % and ccontents of 0.4 to 2.2 wt %. The kinematic viscosity is measured using damped torsio...
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The kinematic viscosity of Fe-Mn-c melts is measured with Mn contents of 5.0, 7.5, 10.0, 12.0, 15.0, 17.5, 20.0, and 25.0 wt % and ccontents of 0.4 to 2.2 wt %. The kinematic viscosity is measured using damped torsional vibrations of a crucible with a melt upon the heating and subsequent cooling of the samples. The temperatures at which the characteristics of the viscous flow change and the liquid-liquid structural transition occurs in Fe-Mn-c melts are determined using the results from measuring the kinematic viscosity.
Sol-gel is a promising technology to prepare the c/c-Zrc-Siccomposites. However, carbon fiber erosion caused by carbothermal reduction severely degrades properties of the composites. At present study, the addition or...
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Sol-gel is a promising technology to prepare the c/c-Zrc-Siccomposites. However, carbon fiber erosion caused by carbothermal reduction severely degrades properties of the composites. At present study, the addition order of carbon source during sol-gel process was optimized to improve the microstructure, mechanical property and ablation resistance of the composites. Results show that adding phenolic resin before gelation combined with deposited pyrocarbon interlayer around the carbon fibers can greatly alleviate the degradation of the c/ c-Zrc-Siccomposites by reducing the carbon fiber erosion. The composites thus prepared delivered the flexural strength, mass and linear ablation rates are 162.58 MPa, 0.147 mg/(cm2.s) and 0.0098 mm/s, respectively, which are 449% higher, 9.26% lower and 38.36% lower than those of the counterpart that added phenolic resin after gelation. The excellent performance is attributed to little erosion of the carbon fibers and the dense matrix of Zrc-Sicceramics obtained from adding carbon source before gelation during the sol-gel process.
A modification of the precursor infiltration pyrolysis (PIP) method was explored to prepare the integrated doped ceramic matrix and coating by the added Sic nanowires layer and shape-stabilization process. The epitaxi...
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A modification of the precursor infiltration pyrolysis (PIP) method was explored to prepare the integrated doped ceramic matrix and coating by the added Sic nanowires layer and shape-stabilization process. The epitaxial layer of Sic nanowires provided surficial attachments for the precursor. And the shape-stabilization process aggregated loose ceramic particles into a coating. Then the Sic nanowire-reinforced Zrc-Siccoating-matrix integrated c/c (S/SZ-cZ/c) composite was simply prepared by the modified PIP method. The bonding strength between the coating and matrix of the S/SZ-cZ/ccomposite was improved. Through the ablation test, the mass and linear ablation rate of the S/SZ-cZ/ccomposite were 0.46 mg/s and 0.67 mu m/s, which were 60.34 % and 74.91 % lower than those of the Sic nanowire-reinforced c/c-Zrc (S/cZ/c) composite, respectively. The integration of the coating and matrix enabled the formation of a continuous oxide layer of molten SiO2 and ZrO2 in the ablation process, which helped to block the oxygen and heat during the ablation test. Thus the ablation resistance of the materials was systematically and effectively improved.
Poor thermal conductivity, especially in thickness direction, is a major obstacle to extend the service lifetime of c/Siccomposite. However, there are few papers focusing on finely designing heat conductive channel b...
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Poor thermal conductivity, especially in thickness direction, is a major obstacle to extend the service lifetime of c/Siccomposite. However, there are few papers focusing on finely designing heat conductive channel but a simply introduction of various modifiers to improve c/Sic thermal conductivity, which leads to less success. Herein, multi-layer graphene sheets were utilized to improve the thermal conductivity of c/Siccomposites via an effective method to design graphene heat conductive channels. To determine the role of graphene sheets in improving thermal conductivity, the effect of the different loading fractions of graphene and microstructure of as-prepared composites were systemically investigated. Results revealed that the thermal conductivity of composites increased by 204% with well-designed graphene heat conductive channels. Besides, compared with the porosity, the orderly aligned heat conductive pathways played a more important role in thermal conductivity. This work provides a new and effective method for preparing well-designed heat conductive channels to enhance thermal conductivity of c/Sic.
Disposal of animal carcasses by co-composting with animal waste usually selected conventional carbon to nitrogen (c/N) ratio around 25:1, in which the compost is widely used throughout the world. In this study, the pi...
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Disposal of animal carcasses by co-composting with animal waste usually selected conventional carbon to nitrogen (c/N) ratio around 25:1, in which the compost is widely used throughout the world. In this study, the pig carcass tissue blocks were sampled for composting at a laboratory scale to evaluate the effect of c/N ratio on the pig carcass compost. The time of thermophilic phase between 60 degrees c - 70 degrees c at a lower c/N ratio of 20:1 was significantly longer than that at the conventional c/N ratio, and it was the only one with the temperature beyond 70 degrees c that lasted for 2 days. Germination index and T value (the final c/N ratio / the initial c/N ratio) of the treatment with a c/N ratio of 20:1 were 94.67% and 0.69, respectively, meeting the standards of animal carcass compost. The degradation rate was 75.67%, and no significant difference was obtained as compared to the conventional c/N ratio groups. Organic fertilizer produced from the treatment with a c/N ratio of 20:1 was selected to evaluate the fertility by pot experiment of cayenne pepper compared with chemical fertilizer. The results showed that organic fertilizer from this treatment could significantly improve the growth of cayenne pepper. Overall, the use of the lower c/N ratio of 20:1 in the disposal of pig carcass by co-composting with swine manure could achieve the similar degradation rate as well as the maturity and stability of organic fertilizer as compared with the traditional c/N ratio at lab scale.
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