1,021 research outputs found
Establishment, optimization, and application of genetic technology in Aspergillus spp.
Aspergillus is widely distributed in nature and occupies a crucial ecological niche, which has complex and diverse metabolic pathways and can produce a variety of metabolites. With the deepening of genomics exploration, more Aspergillus genomic informations have been elucidated, which not only help us understand the basic mechanism of various life activities, but also further realize the ideal functional transformation. Available genetic engineering tools include homologous recombinant systems, specific nuclease based systems, and RNA techniques, combined with transformation methods, and screening based on selective labeling. Precise editing of target genes can not only prevent and control the production of mycotoxin pollutants, but also realize the construction of economical and efficient fungal cell factories. This paper reviewed the establishment and optimization process of genome technologies, hoping to provide the theoretical basis of experiments, and summarized the recent progress and application in genetic technology, analyzes the challenges and the possibility of future development with regard to Aspergillus
A meta-modelling language definition for specific domain
Model Driven software development has been considered to be a further software construction technology following object-oriented software development methods and with the potential to bring new breakthroughs in the research of software development. With deepening research, a growing number of Model Driven software development methods have been proposed. The model is now widely used in all aspects of software development. One key element determining progress in Model Driven software development research is how to better express and describe the models required for various software components. From a study of current Model Driven development technologies and methods, Domain-Specific Modelling is suggested in the thesis as a Model Driven method to better realise the potential of Model-Driven Software Development.
Domain-specific modelling methods can be successfully applied to actual software development projects, which need a flexible and easy to extend, meta-modelling language to provide support. There is a particular requirement for modelling languages based on domain-specific modelling methods in Meta-modelling as most general modelling languages are not suitable. The thesis focuses on implementation of domain-specific modelling methods. The "domain" is stressed as a keystone of software design and development and this is what most differentiates the approach from general software development process and methods. Concerning the design of meta-modelling languages, the meta-modelling language based on XML is defined including its abstract syntax, concrete syntax and semantics. It can support description and construction of the domain meta-model and the domain application model. It can effectively realise visual descriptions, domain objects descriptions, relationships descriptions and rules relationships of domain model. In the area of supporting tools, a meta-meta model is given. The meta-meta model provides a group of general basic component meta-model elements together with the relationships between elements for the construction of the domain meta-model. It can support multi-view, multi-level description of the domain model. Developers or domain experts can complete the design and construction of the domain-specific meta-model and the domain application model in the integrated modelling environment. The thesis has laid the foundation necessary for research in descriptive languages through further study in key technologies of meta-modelling languages based on Model Driven development
Aqua[4-chloro-2-(2-pyridylmethyliminomethyl)phenolato]copper(II) nitrate monohydrate
In the title mononuclear complex, [Cu(C13H10ClN2O)(H2O)]NO3·H2O, the CuII atom is four-coordinated by two N atoms and one O atom of the tridentate Schiff base ligand and one O atom from the coordinated water molecule in a slightly distorted square-planar configuration. The nitrate ion interacts with the copper center [Cu1⋯O3 = 2.579 (4) Å]. In the crystal, the cations, anions and water molecules are linked by O—H⋯O and O—H⋯N hydrogen bonds
Mechanical properties and structural health monitoring performance of carbon nanotube-modified FRP composites:A review
This article provides an extensive review of key publications covering topics of fabrication methods, enhancement of mechanical properties, and applications of CNT-modified FRP materials in structural health monitorin
An optimized encoding algorithm for systematic polar codes
Many different encoding algorithms for systematic polar codes (SPC) have been introduced since SPC was proposed in 2011. However, the number of the computing units of exclusive OR (XOR) has not been optimized yet. According to an iterative property of the generator matrix and particular lower triangular structure of the matrix, we propose an optimized encoding algorithm (OEA) of SPC that can reduce the number of XOR computing units compared with existing non-recursive algorithms. We also prove that this property of the generator matrix could extend to different code lengths and rates of the polar codes. Through the matrix segmentation and transformation, we obtain a submatrix with all zero elements to save computation resources. The proportion of zero elements in the matrix can reach up to 58.5{\%} from the OEA for SPC when the code length and code rate are 2048 and 0.5, respectively. Furthermore, the proposed OEA is beneficial to hardware implementation compared with the existing recursive algorithms in which signals are transmitted bidirectionally
Asymptotic Performance Analysis of Large-Scale Active IRS-Aided Wireless Network
In this paper, the dominant factor affecting the performance of active
IRS-aided wireless communication networks in Rayleigh fading channel, namely
the average signal-to-noise ratio (SNR) gamma0 at IRS, is defined and proposed.
Making use of the weak law of large numbers, its simple asymptotic expression
is derived as the number of IRS elements goes to medium-scale and
large-scale. When N tends to large-scale, the asymptotic received SNR at user
is proved to be a linear increasing function of a product of gamma0 and N.
Subsequently, when the BS transmit power is fixed, there exists an optimal
limited reflect power at IRS. At this point, more IRS reflect power will
degrade the SNR performance. Additionally, under the total power sum constraint
of the BS transmit power and the power reflected by the IRS, an optimal power
allocation (PA) strategy is derived and shown to achieve 0.83 bit rate gain
over equal PA. Finally, an IRS with finite phase shifters is taken into
account, generates phase quantization errors, and further leads to a
degradation of receive performance. The corresponding closed-form performance
loss expressions for user's asymptotic SNR, achievable rate (AR), and bit error
rate (BER) for active IRS and passive IRS are derived. Numerical simulations
show that a 3-bit or 2-bit discrete phase shifter is required to achieve a
trivial performance loss for a large-scale active and passive IRS,
respectively
Effect of total flavonoids from Drynaria rhizome on bone loss in ovariectomized rats
Purpose: To determine the potential effect of total flavonoids from Drynaria rhizome on bone loss in ovariectomized (OVX) rats.
Methods: The rats were divided into four groups: normal control, ovariectomized (OVX) control, and two Drynaria rhizome (DR) flavonoids treatments. Post-operation, osteoporotic OVX rats were given Drynaria rhizome total flavonoids for 3 months. Thereafter, the expressions of bone-related genes and biochemical indices were investigated in samples taken from rat serum and bone.
Results: Treatment with total flavonoids from Drynaria rhizome prevented bone mineral loss and improved some related biochemical indices associated with osteoporosis, namely, alkaline phosphatase (ALP), tartrate-resistant acid phosphatase (TRAP), bone gla protein (BGP) and estradiol (E2). Reverse transcription-polymerase chain reaction (RT-PCR) data showed that treatment with the total flavonoids significantly downregulated mRNA expression of Wnt10b, β-catenin, recombinant human bone morphogenetic protein-2 (BMP2) and BMP4 in OVX rats, but significantly reversed OVX-induced downregulation of dickkopf1 (Dkk1) mRNA expression.
Conclusion: These results indicate that total flavonoids from Drynaria rhizome exert anti-osteoporotic effects in rats through the WNT signaling and BMP-2 signaling pathways
An optimized high-performance liquid chromatography (HPLC) method for benzoylmesaconine determination in Radix Aconiti Lateralis Preparata (Fuzi, aconite roots) and its products
<p>Abstract</p> <p>Background</p> <p>Benzoylmesaconine (BMA) is the main <it>Aconitum </it>alkaloid in <it>Radix Aconiti Lateralis Preparata </it>(<it>Fuzi</it>, aconite roots) with potent pharmacological activities, such as analgesia and anti-inflammation. The present study developed a simple and reliable method using BMA as a marker compound for the quality control of processed aconite roots and their products.</p> <p>Methods</p> <p>After extraction, a high-performance liquid chromatography (HPLC) determination of BMA was conducted on a RP-C<sub>18 </sub>column by gradient elution with acetonitrile and aqueous phase, containing 0.1% phosphoric acid adjusted with triethylamine to pH 3.0.</p> <p>Results</p> <p>A distinct peak profile was obtained and separation of BMA was achieved. Method validation showed that the relative standard deviations (RSDs) of the precision of BMA in all intra-day and inter-day assays were less than 1.36%, and that the average recovery rate was 96.95%. Quantitative analysis of BMA showed that the content of BMA varied significantly in processed aconite roots and their products.</p> <p>Conclusion</p> <p>This HPLC method using BMA as a marker compound is applicable to the quality control of processed aconite roots and their products.</p
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