Microgrid (MG) system with multienergy resources has a wide and dispatchable generation range and shows instant response, therefore, constituting a potentially suitable real-time power balancing ...resource. In this paper, we introduce the concept of MG aggregator to involve small-scale MGs in real-time balancing market bidding via a hierarchical market framework. At the upper real-time market level, the bidding strategy of aggregator is optimized by a risk-constrained mean-variance model to depress the effects of renewable energy sources (RES) uncertainty; at the lower intramarket level, an event-driven mechanism is presented to reach the cleared quantity of the upper market while realizing maximum economy. Furthermore, the above-centralized self-scheduling problem of MG aggregator is decomposed into individual MG optimization problems to achieve an optimal solution with fast convergence. Simulation results verify that the proposed market framework and the bidding strategy for MG aggregator are of high applicability in real market environment.
In the fight against COVID-19, there remains an unmet need for point-of-care (POC) diagnostic testing tools that can rapidly and sensitively detect the causative SARS-CoV-2 virus to control disease ...transmission and improve patient management. Emerging CRISPR-Cas-assisted SARS-CoV-2 detection assays are viewed as transformative solutions for POC diagnostic testing, but their lack of streamlined sample preparation and full integration within an automated and portable device hamper their potential for POC use. We report herein POC-CRISPR – a single-step CRISPR-Cas-assisted assay that incoporates sample preparation with minimal manual operation via facile magnetic-based nucleic acid concentration and transport. Moreover, POC-CRISPR has been adapted into a compact thermoplastic cartridge within a palm-sized yet fully-integrated and automated device. During analytical evaluation, POC-CRISPR was able detect 1 genome equivalent/μL SARS-CoV-2 RNA from a sample volume of 100 μL in < 30 min. When evaluated with 27 unprocessed clinical nasopharyngeal swab eluates that were pre-typed by standard RT-qPCR (Cq values ranged from 18.3 to 30.2 for the positive samples), POC-CRISPR achieved 27 out of 27 concordance and could detect positive samples with high SARS-CoV-2 loads (Cq < 25) in 20 min.
•POC-CRISPR is a point-of-care amenable CRISPR-based sensing assay•The 1-step assay couples magnetofluidic sample preparation and CRISPR-aided RT-RPA•The assay is automated in a low-cost plastic cartridge and a palm-sized device•POC-CRISPR is evaluated with unprocessed clinical swab eluates (n = 27)•POC-CRISPR detects SARS-CoV-2 positive samples with high viral loads in 20 min
The association between macrocephaly and autism spectrum disorder (ASD) suggests that the mechanisms underlying excessive neural growth could contribute to ASD pathogenesis. Consistently, neural ...progenitor cells (NPCs) derived from human induced pluripotent stem cells (hiPSCs) of ASD individuals with early developmental brain enlargement are inherently more proliferative than control NPCs. Here, we show that hiPSC-derived NPCs from ASD individuals with macrocephaly display an altered DNA replication program and increased DNA damage. When compared with the control NPCs, high-throughput genome-wide translocation sequencing (HTGTS) demonstrates that ASD-derived NPCs harbored elevated DNA double-strand breaks in replication stress-susceptible genes, some of which are associated with ASD pathogenesis. Our results provide a mechanism linking hyperproliferation of NPCs with the pathogenesis of ASD by disrupting long neural genes involved in cell-cell adhesion and migration.
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•NPCs derived from macrocephalic ASD patients exhibit replication stress•Replication stress induces replication-transcription conflicts•Replication stress induces DSB hotspots in genes in human NPCs•ASD-derived NPCs show aberrant adherens junctions, apical polarity, and migration
Replication stress poses threats to genome stability. Wang et al. show that macrocephalic ASD patient-specific neural progenitor cells display increased DNA damage in a group of long neural genes vulnerable to replication stress, some of which are associated with the pathogenesis of ASD.
To improve the safety of orthotropic steel bridge decks and the construction efficiency of bridge deck pavement by enhancing the performance of pavement materials, a new-generation, high-performance ...cold-mix resin was prepared by carrying out the combination of micro-characteristic analysis and performance test. Meanwhile, the pavement performance and fatigue performance of high-performance cold-mix resin mixtures and hot-mix epoxy saphalt mixtures as a control group were studied experimentally. The results show that different kinds of epoxy resins show bisphenol structure in essence. The curing exothermic peak temperature of the cold-mix resin increases with the heating rate. Both the specific heat capacity (△CP) of cold-mix resin and cold-mix resin asphalts exhibit a sudden change between −20 °C and 40 °C. In resin asphalt mixtures, cold-mix resin forms the network structure skeleton whereas the asphalt distributed in the form of tiny particles. The dosage of respective component has a significant effect on the tensile strength and elongation at break of cold-mix resin. Compared with hot-mix epoxy asphalt mixtures, cold-mix resin mixtures exhibit comparable water stability and high and low-temperature performance, as well as greater fatigue life.
Micropile groups (MPGs) are an effective means of geological disaster prevention for small- and medium-sized landslides, with the advantages of light structures and convenient construction. However, ...the mechanical and deformation characteristics of MPGs are complex, and their practical application is ahead of theoretical research, which greatly limits the popularization and application of MPGs. This paper conducts a series of centrifuge model tests to investigate the mechanical and deformation characteristics and the antislip mechanism of MPGs, then compare them with those of conventional piles (CPs). In particular, MPGs with and without the platform in the strengthening process of the talus slope are compared, and monitoring the reinforcement effect of MPGs subjected to gravity loading. The results suggest that the soil pressure shows a triangular distribution pattern and is influenced by the position of the potential slip zone and the geometry of the bedrock surface. The compatibility deformation of the pile-soil leads to the stress release of the soil behind the pile, which is an important part affecting the antislip mechanism of the MPG. The platform limits 75% of the pile top displacement of the MPG and simultaneously redistributes the stress of the piles, providing a better overall antislip effect of the pile-soil composite.
Objective
To enhance biotin production in
Escherichia coli
by engineering a heterologous biotin synthetic pathway.
Results
Biotin operon genes from
Pseudomonas putida,
which consisted of a
bioBFHCD
...cluster and a
bioA
gene, was engineered into
Escherichia coli
for biotin production. The introduction of
bioW
gene from
Bacillus subtilis
, encoding pimeloyl-CoA synthetase and
sam2
gene from
Saccharomyces cerevisiae
, encoding S-adenosyl-L-methionine (SAM) synthetase contributed to the heterologous production of biotin in recombinant
E. coli
. Furthermore, biotin production was efficiently enhanced by optimization of the fermentation compositions, especially pimelic acid and L-methionine, the precursor related to the pimeloyl-CoA and SAM synthesis, respectively. The combination of overexpression of the heterologous biotin operon genes and enhanced supply of key intermediate pimeloyl-CoA and SAM increased biotin production in
E. coli
by more than 121-fold. With bioprocess engineering efforts, biotin was produced at a final titer of 92.6 mg/L in a shake flask and 208.7 mg/L in a fed-batch fermenter.
Conclusion
Through introduction of heterologous biotin synthetic pathway, increasing the supply of precursor pimeloyl-CoA and cofactor SAM can significantly enhance biotin production in
E. coli
.
Nanostructure-based sensors are capable of sensitive and label-free detection for biomedical applications. However, high-throughput and low-cost fabrication techniques are the main issues which ...should be addressed. In this study, chip-based nanostructures for intensity-sensitive detection were fabricated and tested using a thermal-annealing-assisted template-stripping method. Large-area uniform nanoslit arrays with a 500 nm period and various slit widths, from 30 to 165 nm, were made on plastic films. A transverse magnetic-polarized wave in these gold nanostructures generated sharp and asymmetric Fano resonances in transmission spectra. The full width at half-maximum bandwidth decreased with the decrease of the slit width. The narrowest bandwidth was smaller than 10 nm. Compared to nanoslit arrays on glass substrates using electron-beam lithography, the proposed chip has a higher intensity sensitivity up to 10367%/RIU (refractive index unit) and reaches a figure of merit up to 55. The higher intensity sensitivity for the template-stripped nanostructure is attributed to a smoother gold surface and larger grain sizes on the plastic film, which reduces the surface plasmon propagation loss.
During selective laser melting (SLM) of K418 powder, the influence of the process parameters, such as laser power P and scanning speed v, on the dynamic thermal behavior and morphology of the melted ...tracks was investigated numerically. A 3D finite difference method was established to predict the dynamic thermal behavior and flow mechanism of K418 powder irradiated by a Gaussian laser beam. A three-dimensional randomly packed powder bed composed of spherical particles was established by discrete element method. The powder particle information including particle size distribution and packing density were taken into account. The volume shrinkage and temperature-dependent thermophysical parameters such as thermal conductivity, specific heat, and other physical properties were also considered. The volume of fluid method was applied to reconstruct the free surface of the molten pool during SLM. The geometrical features, continuity boundaries, and irregularities of the molten pool were proved to be largely determined by the laser energy density. The numerical results are in good agreement with the experiments, which prove to be reasonable and effective. The results provide us some in-depth insight into the complex physical behavior during SLM and guide the optimization of process parameters.
Improper acetabulum component position is a significant risk factor for postoperative dislocation after total hip arthroplasty. Several radiographic two‐dimensional methods exist for measuring ...acetabulum component anteversion, but they cannot distinguish between anteversion and retroversion. “Liaw's version,” initially proposed as a simple mathematical standardized two‐dimensional method, was modified to the computerized ellipse method, proving superior accuracy to traditional two‐dimensional methods. In this article, we demonstrated its application in detecting and measuring retroverted acetabulum component. We obtained anteroposterior pelvis radiographs from a patient undergoing total hip arthroplasty on the day of surgery and 2 weeks postoperatively. The computerized ellipse method was used to measure the acetabulum component orientation. Upon comparison, the difference between θ assigned to be retroverted (9.52–8.56 = 0.96) is much smaller than the difference between θ assigned to be anteverted (23.81–18.86 = 4.95), leading us to determine retroversion. This was further confirmed by computed tomography at the 6‐week follow‐up. We propose that using the computerized ellipse method to measure Liaw's version can be a valuable tool in identifying acetabulum component retroversion on anteroposterior radiographs during routine postoperative follow‐up and retrospective assessments of total hip arthroplasty patients.
The computerized ellipse method, as far as we know, is the first two‐dimensional radiographic method capable of distinguishing retroverted acetabular components in plain radiographs. The Elliversion software facilitates a quick and easy measurement process. Although further cases are necessary to determine the reliability of this method, it can be suggested as a tool for detecting acetabular component retroversion on anteroposterior radiographs during routine postoperative follow‐up and retrospective reviews of patients who have undergone THA.
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