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Objective To evaluate the effects of high glucose on oxidative stress, autophagy, and apoptosis in MC3T3-E1 cells co-cultured with Raw264.7 cells. Methods ① Raw264.7 cells were separated into 3 groups based on the glucose levels in the medium (25, 30, and 35 mmol/L). Flow cytometry was used to detect CD86 expression. RT-qPCR was employed to detect the mRNA expression levels of IL-6, TNF-α, iNOS, NOX2, and p47phox in Raw264.7 cells. Western blotting was used to detect the protein expression level of iNOS. The DCFH-DA probe was used to measure the level of reactive oxygen species (ROS) in Raw264.7 cells. ②MC3T3-E1 cells were divided into 3 groups: normal glucose group (5.5 mmol/L glucose, 5.5-Mono), high glucose mono-culture group (35 mmol/L glucose, 35-Mono) and high glucose co-culture group (co-cultured with Raw264.7 for 24 h, 35-Co). The ROS level of MC3T3-E1 cells were detected by DCFH-DA probe. The autophagic level was assessed by transmission electron microscopy (TEM) and the expression of related proteins was detected with Western blotting. Flow cytometry was applied to determine the rate of apoptosis. Results Compared with the normal glucose group, the expression level of CD86 in Raw 264.7 cells was increased in other high glucose groups. Compared with the 25 mmol/L group, the mRNA levels of IL-6, TNF-α, iNOS, NOX2, and p47phox were increased (P < 0.05), the protein level of iNOS was elevated (P < 0.05) and the ROS level in the Raw264.7 cells was raised in the 35mmol/L group as well. Compared with the normal glucose group, the ROS level of MC3T3-E1 cells in the high glucose groups was increased, especially in high glucose co-culture group. The number of autophagolysosomes in the MC3T3-E1 cells were increased sharply in the high glucose co-culture group. The protein levels of LC3-II and SQSTM1/p62 in MC3T3-E1 cells were increased significantly in the high glucose co-culture group (P < 0.05). The apoptotic rate of MC3T3-E1 cells was significantly higher in the high glucose co-culture group than the high glucose mono-culture group (P < 0.05). Conclusion Co-culture with M1-polarized Raw264.7 cells under high glucose induces apoptosis in MC3T3-E1 cells, which may be related to the production of ROS and over-enhancement of autophagy in MC3T3-E1 cells.

The reaction temperature and time on the carbon loss of coke during CO2 gasification were studied. The results showed that there were significant correlations among the reactivity, pulverization rate, and wear resistance. The degree of variation in pulverization rate and wear resistance revealed that coke reactivity changed dramatically as reaction temperature rose. The temperature was also the key factor for coke graphitization. The evolution of the inorganic minerals and pore wall microstructure was investigated after coke gasification. The migration and accumulation of inorganic minerals, such as mullite, calcium ferrite, and iron oxide in coke, were discovered to catalyze the deterioration of the coke pore wall, resulting in the coke powder formation. The graphitization degree of the skin layer was greater than that of the core after high-temperature reactions, which accelerated skin layer separation from the core. [ABSTRACT FROM AUTHOR]

A large amount of transverse aeolian ridges (TARs) bedforms exist in the Zhurong rover landing region. The acquisition of high‐resolution data from the orbiter and the rover from Tianwen‐1 mission provides an excellent opportunity to study the geological characteristics of TARs. The length, width, and density of a total of 8,274 TAR samples at the landing site were analyzed. The orientation of TARs at the landing region is dominated in the E‐W direction. Analysis of Mars Climate Station (MCS) data on the Zhurong rover shows that the present‐day wind direction is inconsistent with the wind forces that promoted the formation of TARs, suggesting that the formation of TARs is dependent on the ancient wind direction. With the help of the Zhurong MarSCoDe shortwave infrared (SWIR) spectrometer data, we investigate the composition of materials including TARs, soil, and rocks, and the results show that their spectra display similar distinct absorptions consistent with the presence of hydrated minerals such as hydrated sulfates. The cemented and dusty crust covering the TARs indicates that the TARs have not migrated for a period of time in the landing site area. Some of the TARs have been eroded into small sand ridges or ripples due to the change in the prevailing wind directions, which may indicate the climate change on Mars. Plain Language Summary: Using the high‐resolution remote sensing images from the orbiter and Zhurong rover of Tianwen‐1 mission, we identified a total of 8,274 aeolian bedforms at the landing site of the rover on the Utopia Planitia. These aeolian bedforms can be classified as transverse aeolian ridges (TARs) according to their morphology, size and other observational features. The detailed geometry such as the length, the width, the density, and orientation of these TARs were characterized and compared with Martian TARs measured in the previous studies. The TARs in the study area were found to have formed in an ancient wind regime. The TARs are covered with bright dust and their surfaces have been cemented. This suggests that these TARs have not moved for a long time. Some of the TARs have been eroded into small sand ripples. The cause of this may be related to the change in the direction of the ancient wind because the current wind direction derived from the Mars Climate Station (MCS) data on the Zhurong rover is found to be different from the ancient wind direction. Key Points: The geomorphology of transverse aeolian ridges (TARs) at Zhurong landing area are mapped and analyzed and the results show that they formed at an ancient wind regimeThe cemented and dusty crust covering the TARs indicate that the TARs have not migrated for a period of timeSome of the TARs have been eroded due to the change of the prevailing wind directions which may indicate the climate change on Mars [ABSTRACT FROM AUTHOR]

Macrophage pyroptosis drives the secretion of IL-1β, which has been recently reported to be a featured salivary biomarker for discriminating periodontitis in the presence of diabetes. This study aimed to explore whether macrophage pyroptosis plays a role in the development of diabetes mellitus–periodontitis, as well as potential therapeutic strategies. By establishing a model of experimental diabetes mellitus–periodontitis in rats, we found that IL-1β and gasdermin D were highly expressed, leading to aggravated destruction of periodontal tissue. MCC950, a potent and selective molecule inhibitor of the NLRP3 inflammasome, effectively inhibited macrophage pyroptosis and attenuated alveolar bone losses in diabetes mellitus–periodontitis. Consistently, in vitro, high glucose could induce macrophage pyroptosis and thus promoted IL-1β production in macrophages stimulated by lipopolysaccharide. In addition, autophagy blockade by high glucose via the mTOR-ULK1 pathway led to severe oxidative stress response in macrophages stimulated by lipopolysaccharide. Activation of autophagy by rapamycin, clearance of mitochondrial ROS by mitoTEMPO, and inhibition of inflammasome by MCC950 could significantly reduce macrophage pyroptosis and IL-1β secretion. Our study demonstrates that hyperglycemia promotes IL-1β production and pyroptosis in macrophages suffered by periodontal microbial stimuli. Modulation of autophagy activity and specific targeting of the ROS-inflammasome pathway may offer promising therapeutic strategies to alleviate diabetes mellitus–periodontitis. [ABSTRACT FROM AUTHOR]

This paper takes the electric car’s power battery (VRLA battery cell) as the research object, for real-time monitoring problem of power battery's state of charge (SOC) and remaining time, The system adopts micro control unit (MCU) 89S51 and AD974 to control battery discharge in constant current, Through the measurement of a periodic, get Series of working voltage, using phase-slope calculation method at this time calculating the battery's SOC and remaining time. Through the experiment, this estimation method proved the feasibility of the dynamic working point can be mapped to the static working point, and the largest relative error is no more than 7 %. For further improving the measurement accuracy and reducing error, Through the software can realize appropriate correction and compensation of temperature, aging and other interference factors. Error analysis results show that this method has small error, high measurement accuracy.

Improving the line-spectrum detection capability of a single hydrophone is of great significance for the passive detection of small underwater platforms. In this paper, we propose a single-hydrophone cross-power spectrum (SHCS) method based on time-domain coherence. This method uses the coherence of the line spectrum and the non-coherence of the continuous spectrum noise to obtain coherent gain and improve the signal-to-noise ratio (SNR) of the line spectrum. The effects of the input SNR, number of averaging operations, and overlap ratio on the performance of the SHCS method under a background of Gaussian white noise are simulated and analyzed. The results show that when the overlap ratio is 0 and the number of averaging operations reaches saturation, the SHCS method can achieve the best performance and about 15 dB coherence gain is obtained. The performance of the SHCS method was verified by sea experiments. Under the extremely low input SNR, in which the line spectrum was almost completely submerged in the marine environmental noise, the SHCS method can obtain about 10 dB coherence gain. Under the conventional input SNR, in which the line spectrum could be observed, the SHCS method can obtain about 13 dB coherence gain. The results of processing the radiated noise from an actual cargo ship also demonstrate the effectiveness of the SHCS method. [ABSTRACT FROM AUTHOR]

Temporomandibular joint osteoarthritis (TMJOA) condylar cartilage degeneration and abnormal subchondral bone pathological remodeling induce pain and joint dysfunction, and cartilage degeneration is considered irreversible. Very few therapeutic approaches are administrated in practice. Nucleotides have demonstrated considerable potential as a next-generation medication, and they have been applied in several models of osteoarthritis. There is a need to establish an effective protocol for TMJOA gene therapy. In the current study unilateral anterior crossbite (UAC) surgery was used to simulate mechanical stress-induced TMJOA in mice. Degeneration of condylar cartilage and destruction of subchondral bone were observed in damaged joints, and miR-181a-5p was elevated in chondrocytes. Intra-articular injection of miR-181a-5p antisense oligonucleotide (ASO) could reduce the cartilage damage and alleviate UAC-induced TMJOA progression, but it did not restore injured subchondral bone. Mechanically, miR-181a-5p evidently targeted the 3' untranslated region of Sirt1 directly, resulting in inhibition of silent information regulator 1 expression and promoting apoptosis by elevating p53-dependent signaling, indicating that miR181a-5p ASO promoted chondrocyte survival. The present study suggests that ASO-based gene therapy may be an effective TMJOA treatment. [ABSTRACT FROM AUTHOR]

In the engineering of underground construction, the discontinuous structures in rock mass have important influences on the mechanical behaviors of the subsurface of rock mass. The acquisition of mechanical parameters is the basis of rock mass engineering design, construction, safety, and stability evaluation. However, the mechanical parameters and failure characteristics of the same rock mass under different mechanical conditions cannot be obtained due to the limitations of specimen preparation techniques. In recent years, with the continuous development of 3D printing (3DP) technology, it has been successfully applied to the repetitive preparation of rock mass samples. The combinations of 3DP and other techniques, such as 3D scanning and CT scanning, provided a new approach to study the mechanical behavior of complex structural rock masses. In this study, through a comprehensive review of the technical progress, equipment situation, application fields, and challenges of the use of 3DP technology, the following conclusions were obtained: (1) 3DP technology has advantages over traditional rock mass specimen preparation techniques, and the verification of test results using 3D printed samples shows that the 3DP has broad application prospects in geotechnical engineering. (2) The combination of 3DP and other advanced techniques can be used to achieve the accurate reconstruction of complex structural rock masses and to obtain the mechanical and failure characteristics of the same rock mass structure under different mechanical boundary conditions. (3) The development of 3DP materials with high strength, high brittleness, and low ductility has become the major bottleneck in the application of 3DP in geotechnical engineering. (4) 3D printers need to meet the high precision and large size requirements while also having high strength and long-term printing ability. The development of 3D printers that can print different types of materials is also an important aspect of the application of 3DP in geotechnical engineering. [ABSTRACT FROM AUTHOR]

Abstract Background Map-based cloning of quantitative trait loci (QTLs) in polyploidy crop species remains a challenge due to the complexity of their genome structures. QTLs for seed weight in B. napus have been identified, but information on candidate genes for identified QTLs of this important trait is still rare. Results In this study, a whole genome genetic linkage map for B. napus was constructed using simple sequence repeat (SSR) markers that covered a genetic distance of 2,126.4 cM with an average distance of 5.36 cM between markers. A procedure was developed to establish colinearity of SSR loci on B. napus with its two progenitor diploid species B. rapa and B. oleracea through extensive bioinformatics analysis. With the aid of B. rapa and B. oleracea genome sequences, the 421 homologous colinear loci deduced from the SSR loci of B. napus were shown to correspond to 398 homologous loci in Arabidopsis thaliana. Through comparative mapping of Arabidopsis and the three Brassica species, 227 homologous genes for seed size/weight were mapped on the B. napus genetic map, establishing the genetic bases for the important agronomic trait in this amphidiploid species. Furthermore, 12 candidate genes underlying 8 QTLs for seed weight were identified, and a gene-specific marker for BnAP2 was developed through molecular cloning using the seed weight/size gene distribution map in B. napus. Conclusions Our study showed that it is feasible to identify candidate genes of QTLs using a SSR-based B. napus genetic map through comparative mapping among Arabidopsis and B. napus and its two progenitor species B. rapa and B. oleracea. Identification of candidate genes for seed weight in amphidiploid B. napus will accelerate the process of isolating the mapped QTLs for this important trait, and this approach may be useful for QTL identification of other traits of agronomic significance.

Summary: Pathogens have evolved various strategies to overcome host immunity for successful infection. Maize chlorotic mottle virus (MCMV) can cause lethal necrosis in maize (Zea mays) when it coinfects with a virus in the Potyviridae family. However, the MCMV pathogenicity determinant remains largely unknown.Here we show that the P31 protein of MCMV is important for viral accumulation and essential for symptom development. Ectopic expression of P31 using foxtail mosaic virus or potato virus X induced necrosis in systemically infected maize or Nicotiana benthamiana leaves.Maize catalases (CATs) were shown to interact with P31 in yeast and in planta. P31 accumulation was elevated through its interaction with ZmCAT1. P31 attenuated the expression of salicylic acid (SA)‐responsive pathogenesis‐related (PR) genes by inhibiting catalase activity during MCMV infection. In addition, silencing of ZmCATs using a brome mosaic virus‐based gene silencing vector facilitated MCMV RNA and coat protein accumulation.This study reveals an important role for MCMV P31 in counteracting host defence and inducing systemic chlorosis and necrosis. Our results have implications for understanding the mechanisms in defence and counter‐defence during infection of plants by various pathogens. [ABSTRACT FROM AUTHOR]

Based on a long-term comprehensive instrumentation program, the performance of an excavation pit constructed by the top-down method in downtown Kunming was extensively examined. The measured excavation responses included the deflections of diaphragm wall, vertical column movement, slab axial force, building settlement caused by ground deformation, and the influence of pit excavation on the adjacent subway tunnel. This paper analyses the monitoring data of the existing construction stage. Based on the analyses on the data of field and numerical simulation, the following major findings were obtained: (1) the relationship between the measured maximum wall deflection, δ h m , and excavation depth, H , in this study is δ h m = 0.06 % H ∼ 0.27 % H , which is quite different compared with the relationship of soft-soil pit δ h m = 0.02 % H ∼ 1.2 % H , but closer to the normalized curve of rock-socketed pile δ h m = 0.01 % H ∼ 0.45 % H and rock-socketed diaphragm wall δ h m = 0.031 % H ∼ 0.129 % H. (2) The relationship between the maximum settlement of column ( δ p ) and excavation depth (H) is δ p = − 0.09 % ∼ 0.04 % H. The maximum distortion between the diaphragm wall and the column is less than 1/500 of the limit range proposed by Bjerrum. (3) The impact range caused by excavation is about 3.8 times the maximum excavation depth. The ground settlement around the foundation pit is groove type, and the maximum settlement point is located at 2.7 times the maximum excavation depth. (4) The excavation of the foundation pit leads to the maximum vertical settlement of 2 mm and maximum horizontal displacement of 5.2 mm in the subway tunnel; the maximum change of axial force and bending moment are 8.8 kN (the vertical direction) and 6.4 kN·m/m (the horizontal direction), respectively. [ABSTRACT FROM AUTHOR]

A common feature of many acute and chronic oral diseases is microbial-induced inflammation. Innate immune responses are the first line of defense against pathogenic microorganisms and are initiated by pattern recognition receptors (PRRs) that specifically recognize pathogen-associated molecular patterns and danger-associated molecular patterns. The activation of certain PRRs can lead to the assembly of macromolecular oligomers termed inflammasomes , which are responsible for pro-inflammatory cytokine maturation and secretion and thus activate host inflammatory responses. About 10 years ago, the absent in melanoma 2 (AIM2) was independently discovered by four research groups, and among the "canonical" inflammasomes [including AIM2, NLR family pyrin domain (NLRP)1, NLRP3, NLR family apoptosis inhibitory protein (NAIP)/NLR family, caspase activation and recruitment domain (CARD) containing (NLRC)4, and pyrin], AIM2 so far is the only one that simultaneously acts as a cytosolic DNA sensor due to its DNA-binding ability. Undoubtedly, such a double-faceted role gives AIM2 greater mission and more potential in the mediation of innate immune responses. Therefore, AIM2 has garnered much attention from the broad scientific community during its first 10 years of discovery (2009–2019). How the AIM2 inflammasome is related to oral diseases has aroused debate over the past few years and is under active investigation. AIM2 inflammasome may potentially be a key link between oral diseases and innate immunity. In this review, we highlight the current knowledge of the AIM2 inflammasome and its critical role in the pathogenesis of various oral diseases, which might offer future possibilities for disease prevention and targeted therapy utilizing this continued understanding. [ABSTRACT FROM AUTHOR]

Mechanical stress plays a critical role in cartilage development and homoeostasis. Chondrocytes are surrounded by a narrow pericellular matrix (PCM), which absorbs dynamic and static forces and transmits them to the chondrocyte surface. Recent studies have demonstrated that molecular components, including perlecan, collagen and hyaluronan, provide distinct physical properties for the PCM and maintain the essential microenvironment of chondrocytes. These physical signals are sensed by receptors and molecules located in the cell membrane, such as Ca2+ channels, the primary cilium and integrins, and a series of downstream molecular pathways are involved in mechanotransduction in cartilage. All mechanoreceptors convert outside signals into chemical and biological signals, which then regulate transcription in chondrocytes in response to mechanical stresses. This review highlights recent progress and focuses on the function of the PCM and cell surface molecules in chondrocyte mechanotransduction. Emerging understanding of the cellular and molecular mechanisms that regulate mechanotransduction will provide new insights into osteoarthritis pathogenesis and precision strategies that could be used in its treatment. [ABSTRACT FROM AUTHOR]

Mitochondrial genes' variants encoded in both the nuclear and mitochondrial genomes can disrupt mitochondrial function, resulting in losing of cartilage and generating osteoarthritis (OA). However, the association between mtDNA haplogroups and OA still lacks strength evidence supporting. The aim of this meta-analysis is to assess the role of mtDNA haplogroups in speculating the pathogenesis and progression of OA. PubMed, Embase, the Cochrane Central Register of Controlled Trials, and World Health Organization clinical trials' registry center were searched to identify relevant studies up to the end of March 2019. Inclusion citations required a case-control or cohort study to demonstrate the association between mtDNA haplogroups and OA's prevalence or progression. Title, abstract, and full-text screening were sequentially assessed by three reviewers. Data were analyzed using STATA. Besides, publication bias and meta-regression analysis were conducted to explore potential heterogeneities. We collected results from 7 articles. The cluster TJ cases showed a lower proportion in OA cases (RR = 0.83, 95% CI 0.72, 0.96). However, there is no evidence that revealed this kind of impact originated from neither type J nor type T individually. Besides, the type B and G analyses among Asian populations also elucidated a negative association. Moreover, the cluster TJ of mtDNA haplogroups revealed a lower cumulative probability of radiographic OA progression (ES = 0.77, 95% CI 0.63, 0.94), which was contributed by type T (ES = 0.61, 95% CI 0.45, 0.82).The mtDNA haplogroups do have impacts on the prevalence and progression of OA. Cluster TJ could help reduce the prevalence and slow down the radiographic changes; however, the impacts came from type J and type T, respectively. [ABSTRACT FROM AUTHOR]

Bone defects caused heavy social and economic burdens worldwide. Nel‐like molecule, type 1 (NELL‐1) could enhance the osteogenesis and the repairment of bone defects, while the specific mechanism remains to be elucidated. Circular RNAs (circRNAs) have been found to play critical roles in the tissue development and serve as biomarkers for various diseases. However, it remains unclear that the expression patterns of circRNAs and the roles of them played in recombinant NELL‐1‐induced osteogenesis of human adipose‐derived stem cells (hASCs). In this study, we performed RNA‐sequencing to investigate the expression profiles of circRNAs in recombinant NELL‐1‐induced osteogenic differentiation and identified two key circRNAs, namely circRFWD2 and circINO80. These two circRNAs were confirmed to be up‐regulated during recombinant NELL‐1‐induced osteogenesis, and knockdown of them affected the positive effect of NELL‐1 on osteogenesis. CircRFWD2 and circINO80 could interact with hsa‐miR‐6817‐5p, which could inhibit the osteogenesis. Silencing hsa‐miR‐6817‐5p could partially reverse the negative effect of si‐circRFWD2 and si‐circINO80 on the osteogenesis. Therefore, circRFWD2 and circINO80 could regulate the expression of hsa‐miR‐6817‐5p and influence the recombinant NELL‐1‐induced osteogenic differentiation of hASCs. It opens a new window to better understanding the effects of NELL‐1 on the osteogenic differentiation of hASCs and provides potential molecular targets and novel methods for bone regeneration efficiently and safely. [ABSTRACT FROM AUTHOR]

Background: Toxoplasma gondii is an obligate intracellular parasite that infects humans and other warm-blooded animals. Previous quantitative proteomic analyses of infected host cells revealed that the expression of many host proteins is modulated by T. gondii infection. However, at present limited data are available on the differentially expressed miRNAs (DEMs) associated with the pathology and host immune responses induced by acute and chronic infection with T. gondii in pigs in vivo. In this study, high-throughput sequencing was used to investigate expression profiles of spleen miRNAs at 10, 25 and 50 days post-infection (DPI) in pigs infected with Chinese I genotype strain T. gondii isolated from a dead pig. Results: When compared to the control group, 34, 6 and 86 DEMs were found in spleens of infected pigs at 10, 25 and 50 DPI, respectively. Gene Ontology (GO) enrichment analysis of the target genes of DEMs showed that no GO terms were enriched at 25 DPI, whereas 28 and 241 GO terms, of which two and 215 were sample-specific, were significantly enriched at 10 and 50 DPI, respectively. The top 20 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways of the target genes of DEMs included signal transduction, immune system, metabolism and diseases. miRNA–gene network analysis revealed that the DEMs played important roles in the host immune response to T. gondii infection by modulating expression levels of cellular immunity-related cytokines and immune-related C-type lectins. Conclusion: Our results not only showed that host miRNA expression is altered by T. gondii but also revealed differences in the regulation of key biological processes and pathways involved in host responses to acute versus chronic T. gondii infection. This will aid future research into miRNA-target interactions during T. gondii infection in pigs and the development of novel therapies against T. gondii. [ABSTRACT FROM AUTHOR]

MicroRNAs (miRNAs) are endogenous non-coding small RNAs that play essential regulatory roles in plant development and environmental stress responses. Maize ( Zea mays L.) is a global economically important food and forage crop. To date, a number of maize miRNAs have been identified as being involved in plant development and stress responses. However, the miRNA-mediated gene regulatory networks responsive to virus infections in maize remain largely unknown. In this study, the profiles of small RNAs in buffer- and Sugarcane mosaic virus (SCMV)-inoculated maize plants were obtained by high-throughput sequencing, respectively. A total of 154 known miRNAs and 213 novel miRNAs were profiled and most of the miRNAs identified were differentially expressed after SCMV infection. In addition, 70 targets of 13 known miRNAs and 3 targets of a novel miRNA were identified by degradome analysis. The results of Northern blotting and quantitative real-time PCR showed that the expression levels of the selected miRNAs and their targets were mostly influenced by SCMV infection at 12 days post inoculation, including up-regulation of miR168 and miR528, and down-regulation of miR159, miR397 and miR827. These results provide new insights into the regulatory networks of miRNAs and their targets in maize plants responsive to SCMV infection. [ABSTRACT FROM AUTHOR]

In this article, the heat transfer performance of a syngas cooler with membrane helical-coil heat exchanger was numerically studied. A method of combining piecewise simulation and full-scale simulation was proposed, and the influence of fly ash was considered. The models and the proposed method were validated by comparing simulation results with data from industrial test. The simulation results show that radiation accounts for 10–20% of the total heat transfer in the syngas cooler. The surface of inner channel is characterized with high convective heat-transfer coefficient and heat flux. In addition, the quality of produced steam could be significantly enhanced as the heat exchanger of upper group was changed from evaporating surface to superheating surface, and the cooling performance for syngas was hardly affected. [ABSTRACT FROM PUBLISHER]

Conjugate heat transfer to supercritical CO2in membrane helical coiled tube heat exchangers has been numerically investigated in the present study. The purpose is to provide detailed information on the conjugate heat transfer behavior for a better understanding of the abnormal heat transfer mechanism of supercritical fluid. It could be concluded that the supercritical fluid mass flux and vertical/horizontal placement would significantly affect the abnormal heat transfer phenomenon in the tube side. The flow field of supercritical fluid is affected by both the buoyancy and centrifugal force in the conjugate heat transfer process. The local wall temperature and heat transfer coefficient in the tube side would rise and fall periodically for the horizontal heat exchanger, but this phenomenon will gradually disappear with the increase of the mass flow rate or fluid temperature in the tube side. The dual effects of buoyancy force and centrifugal force lead to the deflection of the second flow direction for the vertical placement, which further results in the heat transfer deterioration region on the top-generatrix wall for the downward flow being larger than that for the upward flow. [ABSTRACT FROM PUBLISHER]

Conjugate cooling heat transfer to supercritical CO2in a vertical double-pipe heat exchanger was numerically investigated in the present study. With the aim to better understand the conjugate cooling mechanism of supercritical fluid, detailed information on heat transfer behavior is provided. The results demonstrate that the numerical results predicted by the Abe, Kondoh, and Nagano (AKN) model show the best agreement with the experimental data. After validation, the influences of cooling water Re and temperature at the shell side, supercritical fluid Re at the tube side, flow direction, and pipe diameter on conjugate cooling heat transfer were investigated based on velocity fields. We conclude that cool water Re and temperature at the shell side have a significant effect on the cooling phenomenon at the tube side. Reduction in heat transfer could be avoided by either an increase in ReCO2or a decrease in di. In addition, variations in density and cpare the most significant factors to determine the occurrence of abnormal heat transfer phenomena. In comparison with the heating process of supercritical CO2, the sharply increased viscosity noted would hinder the distortion of the flow field to ameliorate heat transfer deterioration during the cooling process. [ABSTRACT FROM AUTHOR]

The present experiment was conducted to determine the dietary vitamin A (VA) requirement of juvenile Wuchang bream by formulating six isonitrogenous and isoenergetic purified experimental diets containing 0, 1934, 3885, 7924, 15,935 and 47,917 IU VA (as retinol acetate) kg − 1 diet, respectively. Each experimental diet was fed to triplicate groups of 25 juveniles each with initial average weights of 2.40 ± 0.01 g in the circular tank for 90 days. Weight gain, protein efficiency ratio, plasma complement 3, plasma complement 4, white blood cell, red blood cell and hemoglobin content significantly increased with increasing dietary VA level, reached a peak with 1934 or 3885 IU kg − 1 VA, and then decreased. Feed conversion ratio (FCR) was lower in the group fed 3885 IU kg − 1 dietary VA than those fed the 0, 15,939 and 47,917 IU kg − 1 VA diets. Hepatosomatic index and plasma alanine aminotransferase activity were higher in fish fed the 0 IU VA kg − 1 diet than those fed with dietary VA. Similar trend was obtained for aspartate aminotransferase activity and the highest activity was found in the group of 47,917 IU kg − 1 VA. The cumulative mortality after Aeromonas hydrophila challenge of the group fed the 3885, 7924 and 15,935 IU kg − 1 VA diets was significantly lower than those fed 0 IU kg − 1 dietary VA. The overall results of the present study indicate that the dietary VA requirement of juvenile Wuchang bream on the bases of the broken-line regression analysis of FCR was estimated to be 3914 IU kg − 1 of diet. Statement of relevance The requirements and immune responses of vitamin A in aquatic animals have been studied in many fish. Dietary deficiency symptoms of vitamin A include skeletal deformity, eye lesions, hemorrhages of fins and eyes, and reduced immunity and growth. Therefore, it is important to know the vitamin A requirement of targeted species and incorporate into diets to prevent deficiency symptoms. Wuchang bream ( M. amblycephala ) is a principal species in Chinese freshwater polyculture systems with production in China of approximately 0.72 million tons in 2012. However, the growth and immune responses associated with vitamin A in Wuchang bream have not been studied. Therefore, the aim of this study was to quantify the dietary vitamin A requirement of Wuchang bream using growth and immunity parameters. The present experiment was conducted to determine the dietary vitamin A (VA) requirement of juvenile Wuchang bream by formulating six isonitrogenous and isoenergetic purified experimental diets containing 0, 1934, 3885, 7924, 15,935 and 47,917 IU VA (as retinol acetate) kg − 1 diet, respectively. Each experimental diet was fed to triplicate groups of 25 juveniles each with initial average weights of 2.40 ± 0.01 g in the circular tank for 90 days. Weight gain, protein efficiency ratio, plasma complement 3, plasma complement 4, white blood cell, red blood cell and hemoglobin content significantly increased with increasing dietary VA level, reached a peak with 1934 or 3885 IU kg − 1 VA, and then decreased. Feed conversion ratio (FCR) was lower in the group fed 3885 IU kg − 1 dietary VA than those fed the 0, 15,939 and 47,917 IU kg − 1 VA diets. Hepatosomatic index and plasma alanine aminotransferase activity were higher in fish fed the 0 IU VA kg − 1 diet than those fed with dietary VA. Similar trend was obtained for aspartate aminotransferase activity and the highest activity was found in the group of 47,917 IU kg − 1 VA. The cumulative mortality after A. hydrophila challenge of the group fed 3885, 7924 and 15,935 IU kg − 1 VA diets was significantly lower than those fed 0 IU kg − 1 dietary VA. In a word, an excess or deficiency of VA reduced WBC, RBC, HBG, C3 and C4 contents, increased blood AST and ALT activities and enhanced morality after A. hydrophila infection. Taken together, our results suggest that the optimum requirement of dietary VA for juvenile Wuchang bream is 3914 IU kg − 1 of diet based on the broken-line regression analysis of FCR versus different dietary VA levels, respectively. [ABSTRACT FROM AUTHOR]

A numerical study on flow and heat transfer in double-wave cross-corrugated passages with different structure parameters was conducted. The three-dimensional governing equations for mass, momentum, and heat transfer were solved using a control volume finite difference method and a validated low-Reynolds number k-ϵmodel. The effects of Reynolds number and structure parameters, including pitch ratio (P1/P2) and height ratio (H1/H2), were studied. It was found that with a decrease in height ratio, the mainstream flow changed from a pattern dominated by L-shaped flow to one dominated by Z-shaped flow, whereas pitch ratio had almost no influence on the flow pattern. The average Nusselt number Nuavfirst increased and then decreased gradually with either an increase in the pitch ratio or a decrease in the height ratio. Pressure drop showed the same trend as heat transfer performance. The best performance evaluation criterion number (g) of double-wave passage was nearly 20% higher than that of the corresponding single-wave passage, whereas the worst was nearly 40% lower. On the whole, the double-wave plate with H1/H2 = 5 showed better overall performance. The double-wave plate with P1/P2 = 1 had better overall performance for Re < 5,000, whereas that with P1/P2 = 3 was better for Re > 7,500. [ABSTRACT FROM AUTHOR]

Conjugate heat transfer to supercritical CO2in a vertical tube-in-tube heat exchanger was numerically investigated. The results demonstrate that most models considered are able to reproduce the heat transfer processes qualitatively, and the Abe, Kondoh, and Nagano model shows optimal agreement with the experimental data. The influences of hot fluid mass flux and temperature of the shell side, supercritical fluid mass flux of the tube side, flow direction, and pipe diameter on conjugate heat transfer were investigated based on velocity and turbulence fields. It is concluded that hot fluid mass flux and temperature of the shell side significantly affect heat transfer of the tube side. Mixed convection is the main heat transfer mechanism for the supercritical CO2conjugate heat transfer process when the inner diameter of the tube is greater than 1 mm. In addition, density variation is highly significant for heat transfer of supercritical CO2while high viscosity hinders the distortion of the flow field and reduces deterioration in heat transfer. [ABSTRACT FROM AUTHOR]

ABSTRACT Numerical simulation was conducted to investigate the flow and heat transfer of high-pressure synthesis gas (syngas) in an annular channel consisting of membrane helical coils. Effects of radial pitch, axial pitch, and inner helical coil diameter were considered. The numerical results are in a good agreement with our previous experimental results of heat transfer in membrane helical-coil annular channels. The average heat transfer coefficient of the membrane helical coil decreases to a constant with the rise of radial pitch; meanwhile, it increases first and decreases afterwards with the increase of axial pitch. Although the local heat transfer coefficients of the inner and outer coil are irrelevant to the coil curvature, the average heat transfer coefficient of inner coil is higher than that of outer coil due to the lower finned ratio of inner coil. © 2011 Curtin University of Technology and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]