107 research outputs found
Numerical Investigation of Flow and Heat Transfer Characteristics in Plate with Multiple Incline Stage Holes
In this paper, the effects of impingement and film composite cooling on the design of combustion chamber cooling structure are simulated by numerical simulation. The focus of the investigation was on increased film cooling efficiency and enhanced heat transfer between the coolant and the hole wall. The five-stage shaped hole model and one cylindrical hole design have the same equivalent flow area. The flow and heat transfer characteristics of cylindrical hole and stage-shaped hole were numerically investigated under same blowing ratio, and compared at the same blowing ratio. The results showed the stage-shaped hole resulted in higher cooling effectiveness, especially in rear part, and the mechanisms of which were studied in details. The consequences of the phase parameters in the flow have very clearly dependedt on the internal shape of the corresponding hole. Stage-shaped holes formed impact inside the wall, tapped the coolant potential in cooling, and increased the heat transfer inside the solid wall. Further, stage-shaped hole resulted in unstabilized flow inside hole, gave an enhancement of lateral spreading ability, and brought a significant increase of the film lateral effectiveness. Further, the affection of area ratio and height ratio has been studied by five models. The results show that the increasing of area ratio leads to an increase in cooling efficiency, which also indicates the increasing of height ratio showed slight affection
Experimental investigation of flow and heat transfer characteristics on matrix ribbed channel
The effect of the rib width to height ratio t/e and width to pitch ratio t/p on
the local heat transfer distribution in a rectangular matrix ribbed channel
with two opposite in line
o 45
ribs are experimentally investigated for
Reynolds Numbers from 54000 to 150000. The rib height to channel height
ratio e/H is 0.5, t/p and t/e both varies in range of 0.3-0.5. And to simulate
the actually situation in turbine blades, and provide useful direct results for
turbine blade designers, the parameters are same with the blade. The
experiments results show that, in comparison to fully developed flow in a
smooth pipe of equivalent hydraulic diameter, the Nusselt number inside the
matrix-ribbed rectangular channel is increased up to 5 to 9 times higher,
while total pressure drop is enlarged by up to significant magnitude. The
Nusselt number ratio increases with t/p and t/e increased. Semi-empirical
heat transfer is developed for designing of cooling channel
Functional evaluation of constructed pseudo-endogenous microRNA-targeted myocardial ultrasound nanobubble
BackgroundStem cell transplantation is one of the treatment methods for acute myocardial infarction (AMI). MicroRNA-1 contributes to the study of the essential mechanisms of stem cell transplantation for treating AMI by targeted regulating the myocardial microenvironment after stem cell transplantation at the post-transcriptional level. Thus, microRNA-1 participates in regulating the myocardial microenvironment after stem cell transplantation, a promising strategy for the Stem cell transplantation treatment of AMI. However, the naked microRNA-1 synthesized is extremely unstable and non-targeting, which can be rapidly degraded by circulating RNase. Herein, to safely and effectively targeted transport the naked microRNA-1 synthesized into myocardial tissue, we will construct pseudo-endogenous microRNA-targeted myocardial ultrasound nanobubble pAd-AAV-9/miRNA-1 NB and evaluate its characteristics, targeting, and function.MethodsThe pAd-AAV-9/miRNA-1 gene complex was linked to nanobubble NBs by the “avidin-biotin bridging” method to prepare cardiomyocyte-targeted nanobubble pAd-AAV-9/miRNA-1 NB. The shape, particle size, dispersion, and stability of nanobubbles and the connection of pAd-AAV-9/miRNA-1 gene complex to nanobubble NB were observed. The virus loading efficiency was determined, and the myocardium-targeting imaging ability was evaluated using contrast-enhanced ultrasound imaging in vivo. The miRNA-1 expression level in myocardial tissue and other vital organs ex vivo of SD rats was considered by Q-PCR. Also, the cytotoxic effects were assessed.ResultsThe particle size of NBs was 504.02 ± 36.94 nm, and that of pAd-AAV-9/miRNA-1 NB was 568.00 ± 37.39 nm. The particle size and concentration of pAd-AAV-9/miRNA-1 NBs did not change significantly within 1 h at room temperature (p > 0.05). pAd-AAV-9/miRNA-1 NB had the highest viral load rate of 86.3 ± 2.2% (p < 0.05), and the optimum viral load was 5 μL (p < 0.05). pAd-AAV-9/miRNA-1 NB had good contrast-enhanced ultrasound imaging in vivo. Quantitative analysis of miRNA-1 expression levels in vital organs ex vivo of SD rats by Q-PCR showed that pAd-AAV-9/miRNA-1 NB targeted the myocardial tissue. Q-PCR indicated that the expression level of miRNA-1 in the myocardium of the pAd-AAV-9/miRNA-1 NB + UTMD group was significantly higher than that of the pAd-AAV-9/miRNA-1 NB group (p < 0.05). pAd-AAV-9/miRNA-1 NB had no cytotoxic effect on cardiomyocytes (p > 0.05).ConclusionThe pAd-AAV-9/miRNA-1 NB constructed in this study could carry naked miRNA-1 synthesized in vitro for targeted transport into myocardial tissue successfully and had sound contrast-enhanced imaging effects in vivo
Multimodal transformer augmented fusion for speech emotion recognition
Speech emotion recognition is challenging due to the subjectivity and ambiguity of emotion. In recent years, multimodal methods for speech emotion recognition have achieved promising results. However, due to the heterogeneity of data from different modalities, effectively integrating different modal information remains a difficulty and breakthrough point of the research. Moreover, in view of the limitations of feature-level fusion and decision-level fusion methods, capturing fine-grained modal interactions has often been neglected in previous studies. We propose a method named multimodal transformer augmented fusion that uses a hybrid fusion strategy, combing feature-level fusion and model-level fusion methods, to perform fine-grained information interaction within and between modalities. A Model-fusion module composed of three Cross-Transformer Encoders is proposed to generate multimodal emotional representation for modal guidance and information fusion. Specifically, the multimodal features obtained by feature-level fusion and text features are used to enhance speech features. Our proposed method outperforms existing state-of-the-art approaches on the IEMOCAP and MELD dataset
Study of an Arctic blowing snow-induced bromine explosion event in Ny-Ålesund, Svalbard
Bromine explosion events (BEEs) are important processes that influence the atmospheric oxidation capacity, especially in the polar troposphere during spring. Although sea ice surface is thought to be a significant bromine source, bromine release mechanisms remain unclear. High-resolution ground-based observations of reactive bromine, such as BrO, are important for assessing the potential impacts on tropospheric ozone and evaluating chemical models. However, previous model studies paid little attention to Svalbard, which is surrounded by both open ocean and sea ice. In this paper, we present continuous BrO slant column densities and vertical column densities derived by Multi-Axis Differential Optical Absorption Spectroscopy deployed at Ny-Ålesund (78.92°N, 11.93°E) in March 2017. We focused on one BEE in mid-March, during which the vertical column densities of BrO surged from 4.26 × 1013 molecular cm−2 to the peak at 1.23 × 1014 molecular cm−2 on March 17, surface ozone depleted from a background level of 46.25 parts per billion by volume (ppbv) to 13.9 ppbv. This case study indicates that the BEE was strongly associated with blowing snow induced by the cyclone systems that approached Svalbard from March 14 to 18. By considering meteorological conditions, sea ice coverage, and airmass trajectory history, we demonstrate that sea salt aerosols (SSAs) from blowing snow on sea ice, rather than from open ocean, are attributed to the occurrence of this BEE. Model results from a parallelized-tropospheric offline model of chemistry and transport (p-TOMCAT) indicate that this BEE was mainly triggered by a blowing snow event associated with a low-pressure cyclone system. The concentration of blowing-snow-sourced SSAs surged to peak when the airmass pass across the sea-ice-covered area under high wind speed, which is a critical factor in the process of bromine explosion observed in Ny-Ålesund. Due to the coarse resolution, the possible delayed timing of bromine release from SSA and the model-data discrepancies still exist
Mitochondrial genome in Hypsizygus marmoreus and its evolution in Dikarya
Background
Hypsizygus marmoreus, a high value commercialized edible mushroom is widely cultivated in East Asia, and has become one of the most popular edible mushrooms because of its rich nutritional and medicinal value. Mitochondria are vital organelles, and play various essential roles in eukaryotic cells.
Results
In this study, we provide the Hypsizygus marmoreus mitochondrial (mt) genome assembly: the circular sequence is 102,752 bp in size and contains 15 putative protein-coding genes, 2 ribosomal RNAs subunits and 28 tRNAs. We compared the mt genomes of the 27 fungal species in the Pezizomycotina and Basidiomycotina subphyla, with the results revealing that H. marmoreus is a sister to Tricholoma matsutake and the phylogenetic distribution of this fungus based on the mt genome. Phylogenetic analysis shows that Ascomycetes mitochondria started to diverge earlier than that of Basidiomycetes and supported the robustness of the hyper metric tree. The fungal sequences are highly polymorphic and gene order varies significantly in the dikarya data set, suggesting a correlation between the gene order and divergence time in the fungi mt genome. To detect the mt genome variations in H. marmoreus, we analyzed the mtDNA sequences of 48 strains. The phylogeny and variation sited type statistics of H. marmoreus provide clear-cut evidence for the existence of four well-defined cultivations isolated lineages, suggesting female ancestor origin of H. marmoreus. Furthermore, variations on two loci were further identified to be molecular markers for distinguishing the subgroup containing 32 strains of other strains. Fifteen conserved protein-coding genes of mtDNAs were analyzed, with fourteen revealed to be under purifying selection in the examined fungal species, suggesting the rapid evolution was caused by positive selection of this gene.
Conclusions
Our studies have provided new reference mt genomes and comparisons between species and intraspecies with other strains, and provided future perspectives for assessing diversity and origin of H. marmoreus.Ope
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A Phytophthora sojae Glycoside Hydrolase 12 Protein Is a Major Virulence Factor during Soybean Infection and Is Recognized as a PAMP
We identified a glycoside hydrolase family 12 (GH12) protein, XEG1, produced by the soybean pathogen Phytophthora sojae that exhibits xyloglucanase and β-glucanase activity. It acts as an important virulence factor during P. sojae infection but also acts as a pathogen-associated molecular pattern (PAMP) in soybean (Glycine max) and solanaceous species, where it can trigger defense responses including cell death. GH12 proteins occur widely across microbial taxa, and many of these GH12 proteins induce cell death in Nicotiana benthamiana. The PAMP activity of XEG1 is independent of its xyloglucanase activity. XEG1 can induce plant defense responses in a BAK1-dependent manner. The perception of XEG1 occurs independently of the perception of ethylene-inducing xylanase. XEG1 is strongly induced in P. sojae within 30 min of infection of soybean and then slowly declines. Both silencing and overexpression of XEG1 in P. sojae severely reduced virulence. Many P. sojae RXLR effectors could suppress defense responses induced by XEG1, including several that are expressed within 30 min of infection. Therefore, our data suggest that PsXEG1 contributes to P. sojae virulence, but soybean recognizes PsXEG1 to induce immune responses, which in turn can be suppressed by RXLR effectors. XEG1 thus represents an apoplastic effector that is recognized via the plant’s PAMP recognition machinery.This is the publisher’s final pdf. The published article is copyrighted by the American Society of Plant Biologists and can be found at: http://www.plantcell.org/content/27/7/205
Disposable sensors in diagnostics, food and environmental monitoring
Disposable sensors are low‐cost and easy‐to‐use sensing devices intended for short‐term or rapid single‐point measurements. The growing demand for fast, accessible, and reliable information in a vastly connected world makes disposable sensors increasingly important. The areas of application for such devices are numerous, ranging from pharmaceutical, agricultural, environmental, forensic, and food sciences to wearables and clinical diagnostics, especially in resource‐limited settings. The capabilities of disposable sensors can extend beyond measuring traditional physical quantities (for example, temperature or pressure); they can provide critical chemical and biological information (chemo‐ and biosensors) that can be digitized and made available to users and centralized/decentralized facilities for data storage, remotely. These features could pave the way for new classes of low‐cost systems for health, food, and environmental monitoring that can democratize sensing across the globe. Here, a brief insight into the materials and basics of sensors (methods of transduction, molecular recognition, and amplification) is provided followed by a comprehensive and critical overview of the disposable sensors currently used for medical diagnostics, food, and environmental analysis. Finally, views on how the field of disposable sensing devices will continue its evolution are discussed, including the future trends, challenges, and opportunities
Real-time Monitoring for the Next Core-Collapse Supernova in JUNO
Core-collapse supernova (CCSN) is one of the most energetic astrophysical
events in the Universe. The early and prompt detection of neutrinos before
(pre-SN) and during the SN burst is a unique opportunity to realize the
multi-messenger observation of the CCSN events. In this work, we describe the
monitoring concept and present the sensitivity of the system to the pre-SN and
SN neutrinos at the Jiangmen Underground Neutrino Observatory (JUNO), which is
a 20 kton liquid scintillator detector under construction in South China. The
real-time monitoring system is designed with both the prompt monitors on the
electronic board and online monitors at the data acquisition stage, in order to
ensure both the alert speed and alert coverage of progenitor stars. By assuming
a false alert rate of 1 per year, this monitoring system can be sensitive to
the pre-SN neutrinos up to the distance of about 1.6 (0.9) kpc and SN neutrinos
up to about 370 (360) kpc for a progenitor mass of 30 for the case
of normal (inverted) mass ordering. The pointing ability of the CCSN is
evaluated by using the accumulated event anisotropy of the inverse beta decay
interactions from pre-SN or SN neutrinos, which, along with the early alert,
can play important roles for the followup multi-messenger observations of the
next Galactic or nearby extragalactic CCSN.Comment: 24 pages, 9 figure
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