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Purpose The objective of this study was to investigate the connection between circular RNA (circRNA) and ischemia-reperfusion (I/R) injury set on by middle cerebral artery occlusion (MCAO) in different parts of the rat brain. Methods Using the MCAO technique, the adult male Sprague-Dawley rat model was created. At 24 hours after reperfusion, circRNA sequencing and real-time PCR were used to assess the circRNA expression profile in the ischemic region of the right cortex, striatum, and hippocampus. A bioinformatics investigation of the changed circRNAs following I/R injury was carried out, including the discovery of miRNA binding sites, analysis of transcription factor binding, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, and Gene Ontology (GO) analysis. Results 85, 113 and 51 circRNAs in the cortex, striatum and hippocampus, respectively, substantially altered (|log2 (fold change)| > 1 and P

Cleidocranial dysplasia (CCD) is a rare, autosomal dominant hereditary disorder characterized by skeletal malformations and dental abnormalities. The purpose of this study was to explore the functional role of a novel mutation in the pathogenesis of CCD. Genomic DNA was extracted from peripheral blood mononuclear cells collected from family members of a Chinese patient with CCD. An analysis of their RUNX Family Transcription Factor 2 (RUNX2) gene sequences was performed by PCR amplification and Sanger sequencing. The function of the mutant RUNX2 was studied by bioinformatics, real-time PCR, western blotting, and subcellular localization analysis. Sanger sequencing identified a novel single-base deletion (NM_001024630.4:c.132delG;NP_001019801.3: Val45Trpfs

BACKGROUND Post-stroke depression (PSD) is the most common psychiatric disorder after stroke and affects recovery of neurological function, ability to return to society, and quality of life of the survivors. Telehealth has been shown to improve depressive symptoms and quality of life of post-stroke patients. However, evidence from clinical trials has not been systematically synthesized. OBJECTIVE This study aims to systematically evaluate the effectiveness of telehealth interventions in reducing depression and anxiety symptoms of post-stroke depression. METHODS The Cochrane Library, PubMed, CINAHL, PsycINFO, CNKI and Wanfang Database were searched to identify randomized controlled trials (RCTs) on effectiveness of telehealth interventions for post-stroke depression from inception to November 30, 2021.The quality of included studies was assessed using the Cochrane risk of bias tool. Data extraction and quality assessment were conducted by two reviewers independently. RevMan 5.4 software was used for Meta-analysis. Data would be synthesized by either the fixed-effect (I2≤50%) or random-effect (I2>50%) model according to a heterogeneity test. RESULTS A total of 10 studies with 1717 participants were included, of which 8 were eligible for meta-analysis. Compared with the control group, the anxiety score of the telemedicine group was lower, with statistical significance (SMD=-1.05, 95%CI-1.22 to -0.89, P CONCLUSIONS Telehealth interventions could availably reduce anxiety symptoms in post-stroke patients, while it had equal salutary effects on depression with the conventional nursing. Therefore large-scale, high-quality randomized controlled trials are needed to further explore the potential of telehealth interventions in terms of mental health for post-stroke patients. CLINICALTRIAL PROSPERO CRD42021291311

KDF1 is a recently identified gene related to tooth development, but it has been little studied. To date, only three cases have been reported in which KDF1 mutations are related to tooth development, including two ectodermal dysplasia cases accompanied by tooth loss and one non-syndromic case with tooth agenesis. However, no KDF1 mutations have been reported as associated with non-syndromic anodontia. Here, the aim was to investigate the genetic etiology of this condition and explore the functional role of a novel KDF1 mutation in a Chinese patient with non-syndromic anodontia.Pathogenic variants were identified by whole-exome and Sanger sequencing. Meanwhile, we conducted a literature review of the reported KDF1 mutations and performed an in vitro functional analysis of four anodontia-causing KDF1 mutations (one novel and three known).We identified a novel de novo missense mutation (c.911 T A, p.I304N) in the KDF1 gene in a Chinese patient with severe non-syndromic anodontia. In vitro functional studies showed altered mRNA and protein expression levels of the mutant KDF1.Our results are the first report of KDF1 missense mutation causing non-syndromic anodontia.This study not only further supports the important role of KDF1 in non-syndromic congenital anodontia, but also expands the spectrum of KDF1 mutations and will contribute to the genetic diagnosis and counselling of families with anodontia.

Background: Mutations of the Ectodysplasin-A (EDA) gene are generally associated with syndrome hypohidrotic ectodermal dysplasia or non-syndromic tooth agenesis. The influence of EDA mutations on dentinogenesis and odontoblast differentiation have not been reported. The aim of this study was to identify genetic clues for the causes of familial non-syndromic oligodontia and explore the underlying mechanisms involved, while focusing on the role of human dental pulp stem cells (hDPSCs). Materials and Methods: Candidate gene sequences were obtained by PCR amplification and Sanger sequencing. Functional analysis was conducted, and the pathogenesis associated with EDA mutations in hDPSCs was investigated to explore the impact of the identified mutation on the phenotype. Capillary electrophoresis (CE) was used to detect X chromosome inactivation (XCI) in the blood of female carriers. Results: In this study, we identified an EDA mutation in a Chinese family：the missense mutation c.1013C>T (Thr338Met). Transfection of hDPSCs with a mutant EDA lentivirus decreased the expression of EDA and dentin sialophosphoprotein (DSPP) compared with transfection of control EDA lentivirus. Mechanistically, mutant EDA inhibited the activation of the NF-κB pathway. The CE results showed that symptomatic female carriers had a skewed XCI with a preferential inactivation of the X chromosome that carried the normal allele. Conclusions: In summary, we demonstrated that EDA mutations result in non-syndromic tooth agenesis in heterozygous females and that, mechanistically, EDA regulates odontogenesis through the NF-κB signalling pathway in hDPSCs. Due to the large heterogeneity of tooth agenesis, this study provided a genetic basis for individuals who exhibit similar clinical phenotypes.

Objectives: The aim of this study was to identify genetic clues for the causes of familial non-syndromic oligodontia and explore the underlying mechanisms involved, while focusing on the role of human dental pulp stem cells (hDPSCs).Materials and Methods: Candidate gene sequences were obtained by PCR amplification and Sanger sequencing. Functional analysis was conducted, and the pathogenesis associated with EDA mutations in hDPSCs was investigated to explore the impact of the identified mutation on the phenotype. Capillary electrophoresis (CE) was used to detect X chromosome inactivation (XCI) in the blood of female carriers.Results: In this study, we identified an EDA mutation in a Chinese family：the missense mutation c.1013C>T (Thr338Met). Transfection of hDPSCs with a mutant EDA lentivirus decreased the expression of EDA and dentin sialophosphoprotein (DSPP) compared with transfection of control EDA lentivirus. Mechanistically, mutant EDA inhibited the activation of the NF-κB pathway. The CE results showed that symptomatic female carriers had a skewed XCI with a preferential inactivation of the X chromosome that carried the normal allele.Conclusions: In summary, we demonstrated that EDA mutations result in non-syndromic tooth agenesis in heterozygous females and that, mechanistically, EDA regulates odontogenesis through the NF-κB signalling pathway in hDPSCs.Clinical Relevance: Due to the large heterogeneity of tooth agenesis, this study provided a genetic basis for individuals who exhibit similar clinical phenotypes.

Background：Osteogenesis imperfecta (OI) is a genetic disorder characterized by bone fragility, blue sclerae and dentinogenesis imperfecta (DGI), which are mainly caused by a mutation of the COL1A1 or COL1A2 genes that encode type I procollagen.Methods: The ultrastructure of dentin was analyzed by micro-CT, scanning electron microscopy, energy-dispersive spectroscopy analysis, nanoindentation test and Toluidine Blue Staining. Whole-exome sequencing (WES) was performed to identify the pathogenic gene. The function of the mutant COL1A1 was studied by real-time PCR, western blotting, subcellular localization. Functional analysis in dental pulp stem cells (DPSCs) was also performed to explore the impact of the identified mutation on this phenotype. Results: WES identified a missense mutation (c.1463G > C) in exon 22 of the COL1A1 gene. However, the cases reported herein only exhibited DGI-I in the clinical phenotype, there is no bone disease and any other common abnormal symptom caused by COL1A1 mutation. In addition, ultrastructural analysis of the tooth affected with non-syndromic DGI-I showed that the abnormal dentin was accompanied by disruption of odontoblast polarization, reduced numbers of odontoblasts, loss of dentinal tubules, and reduction in hardness and elasticity, suggesting severe developmental disturbance. What’s more, the odontoblast differentiation ability based on DPSCs that were isolated and cultured from the DGI-I patient was enhanced compared with those from an age-matched, healthy control.Conclusion: This study helped the family members to understand the disease progression and provided new insights into the phenotype-genotype association in collagen-associated diseases and improve clinical diagnosis of OI/DGI-I.

Exponential damping is an improved version of the viscous damping model and better represent energy dissipation character of actual structures. This study aims at verifying the applicability of the exponential damping model for concrete structures and the accuracy of model parameter identification methods. In this paper, the dynamic tests are conducted on a series of reinforced concrete cantilever beams to obtain frequency response functions. The obtained results show that the exponential damping model can better reflect the energy dissipation capacity of concrete components, especially in the high frequency vibration modal. The recently proposed identification method based on FEM updating for the exponential damping system can predict accurately not only natural frequencies but also the FRFs of concrete beams. The research of the exponential damping will increase the accuracy and efficiency of dynamic behavior analysis of actual concrete structures.

Background. Exosomes from human dental pulp stem cells (hDPSCs) were indicated to play a positive role in vascular regeneration processes. But the angiogenic capabilities of exosomes from inflammatory hDPSCs and the underlying mechanism remain unknown. In this study, the inflammatory factor lipopolysaccharide (LPS) was used to stimulate hDPSCs, and exosomes were extracted from these hDPSCs. The proangiogenic potential of exosomes was examined, and the underlying mechanism was studied. Method. Exosomes were isolated from hDPSCs with or without LPS stimulation (N-EXO and LPS-EXO) and cocultured with human umbilical vein endothelial cells (HUVECs). The proangiogenic potential of exosomes was evaluated by endothelial cell proliferation, migration, and tube formation abilities in vitro. To investigate the proangiogenic mechanism of LPS-EXO, microRNA sequencing was performed to explore the microRNA profile of N-EXO and LPS-EXO. Gene Ontology (GO) analysis was used to study the functions of the predicted target genes. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis was used to estimate the signaling pathways associated with the inflammation-induced angiogenesis process. Result. Compared to the uptake of N-EXO, uptake of LPS-EXO activated the angiogenic potential of HUVECs by promoting the proliferation, migration, and tube formation abilities in vitro. The mRNA expression levels of vascular endothelial growth factor (VEGF) and kinase-insert domain-containing receptor (KDR) in the LPS-EXO group were significantly higher than those in the N-EXO group. MicroRNA sequencing showed that 10 microRNAs were significantly changed in LPS-EXO. Pathway analysis showed that the genes targeted by differentially expressed microRNAs were involved in multiple angiogenesis-related pathways. Conclusion. This study revealed that exosomes derived from inflammatory hDPSCs possessed better proangiogenic potential in vitro. This is the first time to explore the role of exosomal microRNA from hDPSCs in inflammation-induced angiogenesis. This finding sheds new light on the effect of inflammation-stimulated hDPSCs on tissue regeneration.

Background: Angiogenesis is fundamental to biomimetic pulp regeneration. Extracellular vesicles (EVs) derived from human dental pulp stem cells (hDPSCs) from patients with periodontitis were reported to have better angiogenic capabilities. However, the underlying regulatory mechanism remains unknown. As an important component of EVs, exosomes from hDPSCs were indicated to play a crucial role in multiple regeneration processes. In this study, the inflammatory factor lipopolysaccharide (LPS) was used to stimulate hDPSCs, and exosomes were extracted from these hDPSCs. The role of exosomes in the angiogenesis of Human Umbilical Vein Endothelial Cells (HUVECs) was examined, and the underlying mechanism was studied.Method: Exosomes were isolated from hDPSCs with or without LPS stimulation. The angiogenic capabilities of HUVECs were evaluated after coculture with exosomes derived from hDPSCs (hDPSC-EXOs) or exosomes derived from LPS-stimulated hDPSCs (LPS-hDPSC-EXOs). Tube formation and migration assays were conducted, and angiogenesis-related mRNA expression was detected. MicroRNA sequencing was performed to explore the microRNA profile of hDPSC-EXOs and LPS-hDPSC-EXOs. Gene Ontology (GO) analysis was used to study the functions of the predicted target genes. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis was used to estimate the signaling pathways associated with the inflammation-induced angiogenesis process.Result: The release of hDPSC-EXOs increased after stimulation with LPS. Compared to endocytosis of hDPSC-EXOs, endocytosis of LPS-hDPSC-EXOs promoted the tube formation and migration of HUVECs. The mRNA expression levels of vascular endothelial growth factor (VEGF) and kinase-insert domain-containing receptor (KDR) in the LPS-hDPSC-EXOs group were significantly higher than those in the hDPSC-EXOs group. MicroRNA sequencing showed that 10 microRNAs were significantly changed in LPS-hDPSC-EXOs; of these microRNAs, 7 were increased, and 3 were decreased. Pathway analysis showed that the genes targeted by differentially expressed microRNAs were involved in multiple angiogenesis-related pathways.Conclusion: This study revealed that exosomes derived from inflammatory hDPSCs displayed a stronger effect on vascular regeneration. It’s the first time to explore the role of exosomal microRNA from hDPSCs in inflammation-induced angiogenesis. This finding sheds new light on the effect of inflammation-stimulated hDPSCs on tissue regeneration.

Background Long noncoding RNAs (lncRNAs) play an important role in the multiple differentiations of mesenchymal stem cells (MSCs). However, few studies have focused on the regulatory mechanism of lncRNAs in the odontogenic differentiation of human dental pulp stem cells (hDPSCs). Methods hDPSCs were induced to differentiate into odontoblasts in vitro, and the expression profiles of lncRNAs, microRNAs (miRNAs), and messenger RNAs (mRNAs) in differentiated and undifferentiated cells were obtained by microarray. Bioinformatics analyses including Gene Ontology (GO) analysis, pathway analysis, and binding site prediction were performed for functional annotation of lncRNA. miRNA/odontogenesis-related gene networks and lncRNA-associated ceRNA networks were constructed. Quantitative reverse-transcription polymerase chain reaction (qRT-PCR) was used to verify the expression of selected genes. RNA fluorescence in situ hybridization (FISH), qRT-PCR, and western blot analysis were used to explore the location and function of lncRNA-G043225. Dual-luciferase reporter assay was performed to confirm the binding sites of miR-588 with G043225 and Fibrillin 1 (FBN1). Results We identified 132 lncRNAs, 114 miRNAs, and 172 mRNAs were differentially expressed. GO analysis demonstrated that regulation of the neurogenic locus notch homolog (Notch), Wnt, and epidermal growth factor receptor (ERBB) signaling pathways and activation of mitogen-activated protein kinase (MAPK) activity were related to odontogenic differentiation. Pathway analysis indicated that the most significant pathway was the forkhead box O (FoxO) signaling pathway, which is related to odontogenic differentiation. Two odontogenesis-related gene-centered lncRNA-associated ceRNA networks were successfully constructed. The qRT-PCR validation results were consistent with the microarray analysis. G043225 mainly locating in cytoplasm was proved to promote the odontogenic differentiation of hDPSCs via miR-588 and FBN1. Conclusion This is the first study revealing lncRNA-associated ceRNA network during odontogenic differentiation of hDPSCs using microarray, and it could provide clues to explore the mechanism of action at the RNA-RNA level as well as novel treatments for dentin regeneration based on stem cells.

The gas combine cycle are widely used in generating electricity and recovering byproduct gas due to its high thermal efficiency, low pollution emission, and excellent regulation capacity. The highly dynamic nature of power demand and byproduct gas forces it to often run at off-design conditions, which in turn reducing the operating reliability of the bottom cycle system. A new steam turbine operational mode is proposed in this paper to ensure the safe operation of the bottom cycle system. Base on the new solving method proposed in Section 3 of this paper, the off-design model consisting of heat recovery generator (HRSG), steam turbine, condenser and water pump is established in MATLAB, and the refropm9.0 and LAPWS-95 are used for obtaining the physical properties of flue gas and steam/water. Then, the off-design characteristic of the bottom cycle system with different steam turbine operational mode is analyzed in detail. The result shows that as the gas turbine load decreases, the bottom cycle system has the best thermal performance under sliding pressure operational mode. However, its high pressure (HP) approach point temperature difference for the sliding pressure operational mode has a significant drop and is less than 2 ℃ below 74.21% load. The constant HP operational mode can obviously elevate the HP approach point temperature difference, however, the irreversible loss of the bottom cycle system is also increased. After the new steam turbine operational mode considering both sliding pressure and fixed HP is adopted, the HP approach point temperature difference is equaled to 2 ℃ bellow 74.21% load, while the thermal performance is better than that for the constant HP operational mode. As the gas turbine load decreases, the thermal efficiency and output power of the bottom cycle system decrease to 26.47% and 71.23 MW at 40% load, which are 0.53% and 1.45 MW higher than that for the constant HP operational mode. By reasonably regulating the HP steam pressure, the new steam turbine operational mode ensure the safe operation of the bottoming cycle at a cost of minimal thermal performance loss.

In this paper, quasi-variational principles for non-conservative damped systems are studied. A Hamiltontype quasi-variational principle for non-conservative systems in analytical mechanics and a quasi-variational principle of potential energy in non-conservative elastodynamics systems are proposed in simplified forms respectively, by using the direct variational integral method. On the basis of the standard linear solid model for viscoelastic materials, the dynamic equations of exponentially damped systems are established through the proposed quasi-variational principles. A distinction between the internal damping described by exponential damping and the external damping described by viscous one in a vibrating structure is according to different physical mechanisms, which gives some indication of the correct mechanism of damping.

The present study aimed to investigate the effects of vascular endothelial growth factor (VEGF) and insulin‑like growth factor‑1 (IGF‑1) on the proliferation, migration and differentiation of human carious dental pulp stem cells (hCDPSCs), and to elucidate the underlying mechanism(s). Cell counting kit‑8 assay was used to detect the effect of different concentrations of IGF‑1 and VEGF on the proliferation of hCDPSCs. Transwell assay was used to detect the migratory ability of the hCDPSCs. Alizarin red and alkaline phosphatase (ALP) staining were used to detect the osteogenic ability of hCDPSCs, whereas the angiogenic ability of the hCDPSCs was tested by tube formation assay. Reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR) and western blotting were used to detect the expression levels of associated genes and proteins. IGF‑1 (100 ng/ml) or VEGF (25 ng/ml) alone were revealed to be able to promote proliferation and migration of hCDPSCs; however, the combined use of IGF‑1 and VEGF enhanced this effect when compared with the use of either agent in isolation. Alizarin red and ALP staining revealed that the use of either VEGF or IGF‑1 alone did not result in any significant effects, whereas their use in combination promoted the osteogenic differentiation of hCDPSCs. In addition, the RT‑qPCR and western blotting analyses revealed that the expression levels of Runt‑related transcription factor 2 (RUNX2), bone sialoprotein (BSP) and ALP were increased upon combined treatment of the cells with VEGF and IGF‑1. The expression levels of VEGF and plateletderived growth factor (PDGF) in hCDPSCs were enhanced upon treatment with either VEGF or IGF‑1 in isolation, with greater effects observed when VEGF and IGF‑1 were added in combination, indicating that VEGF and IGF‑1 may exert a synergistic role in these events. Further experiments revealed that the combination of VEGF and IGF‑1 led to an activation of the AKT signaling pathway. The proliferation and angiogenesis of hCDPSCs were also shown to be more effective compared with treatment with either VEGF or IGF‑1 in isolation. Taken together, the present study has demonstrated that the combined use of VEGF and IGF‑1 leads to an increase in the proliferation, migration, osteogenesis and angiogenesis of hCDPSCs and, furthermore, these signaling molecules may mediate their effects via activation of the AKT signaling pathway.

A heat transfer model was applied to simulate heat exchange in a direct contact counter current moving bed (CCMB) heat exchanger associated with a dry slag granulation process developed by CSIRO. Cold air is used to recover heat from hot solid slag granules in the heat exchanger. Experimental data was used to calibrate the heat transfer model. The model was then used to predict the solid and gas temperature distributions along the height of the bed, the heat loss, and the operating and design conditions for scale-up of the CCMB to semi-industrial and industrial operations. Two scenarios were examined using the model to determine conditions for i) minimising the solid outlet temperature and ii) maximising the gas outlet temperature. The model can also be used to determine the nominal bed height to ensure that the designed gas outlet temperature is achieved. The modelling results suggest that a relatively small bed height (below 0.5 m) will be sufficient for heat exchange. The model also suggests that a solid to gas mass flow rate ratio of 0.8 should be used to minimise the solid outlet temperature, while a ratio of 1.0 should be used to maximise the gas outlet temperature. Therefore an appropriate operating window for a CCMB heat exchanger for recovering heat from hot slag was found with a solid to gas mass flow rate ratio between 0.8 and 1.

This paper provides a summary of the progress made over the 8 years of an R&D program that focused on the development of know-how and processes that could result in substantial reduction in net CO2 emission by the steel industry. The processes that were developed covered introduction of renewable carbon and energy sources as well as minimising waste heat from processes. The current status of each of the processes and application areas is provided. The use of biomass-derived fuels and reductants in the ironmaking and steelmaking industry provides a sustainable option for reducing net CO2 emissions at a lower capital cost and technological risk than other breakthrough technologies under development. A key focus of this program has been to partially substitute these fossil-based fuels with renewable carbon (charcoal) from sustainable sources such as plantations of biomass species or forest wastes. Raw biomass is unsuitable for applications in ironmaking and steelmaking and should be converted into charcoal (char) through a pyrolysis process before use. A new pyrolysis process which operates continuously and autogenously has been developed and piloted. The biomass-derived chars and hydrocarbon fuels have great potential in lowering the net CO2 emissions of integrated (BF-BOF route) steel plants. Life cycle assessment has quantified the potential reduction in net CO2 emissions and covers cradle to gate, including plantation, harvesting, transport, pyrolysis and use of chars and bio-oil products. The properties of chars produced by biomass pyrolysis can be tailored to each of the several applications proposed (sintering solid fuel, cokemaking blend component, blast furnace tuyere injectant, liquid steel recarburiser, etc.), thus resulting in optimal performance and greater value-in-use of the char. Our economic analysis has made allowance for such value-in-use in applications, particularly as a replacement for BF pulverised coal injection. This analysis shows that key factors influencing the economics are the net cost of producing charcoal from biomass, selection of pyrolysis technology, value of the pyrolysis by-products, as well as the value-in-use for the charcoal. Dry slag granulation (DSG) has the potential to make a fundamental change in slag treatment and deliver a more sustainable alternative compared with the conventional water granulation process. The DSG process not only saves valuable water resources and reduces sulphurous emissions, but it may also recover a large amount of the high-grade heat in molten slag so to reduce greenhouse gas emission. CSIRO has been working on the development of a novel DSG process, integrated with heat recovery, since 2002 and has made significant progress in process design and optimisation based on process modelling, laboratory investigations, extensive pilot plant trials and characterisation of the solidified product granules.

This paper presents a concurrent high-efficiency tri-band power amplifier with the continuous class-E mode. The continuous class-E power amplifier can perform high-efficient concurrently at some operational frequencies by manipulating the fundamental and second harmonic impedances of the transistor. After selected the design parameters of the proposed tri-band power amplifier, the output and input microstrip lines matching network are directly optimizing by the mixed particle swarm optimization-genetic algorithm, which can accelerate the convergence speed of the matching networks comparing with the standard particle swarm optimization algorithm. To verify the proposed design methodology, a tri-band power amplifier at 1.7 GHz, 2.6 GHz and 3.0 GHz is designed. The measured results show that the fabricated power amplifier delivers more than 40 dBm output power with 62%, 64% and 64% PAE at 1.7 GHz, 2.6 GHz and 3.0 GHz, respectively.

A new potential damping model for the dynamic analysis of systems is called exponential damping. This article shows that the finite element model updated method for the systems with exponential damping can accurately predict not only the natural frequencies but also the frequency response functions (FRFs) of the systems. A complex mode procedure for identifying the exponential damping model and its applicability and limitations is presented. A new iterative method for relaxation factor, which is simple, direct, and compatible with conventional modal testing procedures is proposed. The proposed method and several related issues are illustrated by numerical examples. Combined with the FRFs-based model updating method, the finite element model with such nonviscous damping is updated.

Material damping affects the dynamic behaviors of engineering structures considerably, but up to till now little research is maintained on influence factors of material damping. Based on the damping-stress function of steel, the material damping of steel beams is obtained by calculating the stress distribution of the beams with an analytical method. Some key influence factors of the material damping, such as boundary condition, amplitude and frequency of excitation, load position as well as the cross-sectional dimension of a steel beam are analyzed respectively. The calculated results show that even in elastic scope, material damping does not remain constant but varies with these influence factors. Although boundary condition affects material damping to some extent, such influence can be neglected when the maximum stress amplitude of the beam is less than the fatigue limit of steel. Exciting frequency, load position and cross-section dimension have great effects on the material damping of the beam which maintain the similar changing trend under different boundary conditions respectively.

Wedelolactone is a major coumarin of Eclipta prostrata, which is used for preventing liver damage. However the effects of wedelolactone on hepatic fibrosis remained unexplored. The purpose of this study was to demonstrate the anti-fibrotic effects of wedelolactone on activated human hepatic stellate cell (HSC) line LX-2 and the possible underlying mechanisms by means of MTT assay, Hoechst staining, as well as real-time quantitative PCR and western blot. The results showed that wedelolactone reduced the cellular viability of LX-2 in a time and dose-dependent manner. After treatment of wedelolactone, the expressions of collagen I and α-smooth muscle actin, two biomarkers of LX-2 activation, were remarkably decreased. The apoptosis of LX-2 cells was induced by wedelolactone accompanied with the decreasing expression of anti-apoptotic Bcl-2 and increasing expression of pro-apoptotic Bax. In addition, phosphorylated status of extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK) was up-regulated, but not in p38. Moreover, wedelolactone significantly repressed the level of phosphorylated inhibitor of nuclear factor κB (IκB) and p65 in nucleus in spite of tumor necrosis factor-α stimulation. In conclusion, wedelolactone could significantly inhibit the activation of LX-2 cells, the underlying mechanisms of which included inducing Bcl-2 family involved apoptosis, up-regulating phosphorylated status of ERK and JNK expressions, and inhibiting nuclear factor-κB (NF-κB) mediated activity. Wedelolactone might present as a useful tool for the prevention and treatment of hepatic fibrosis.

In this paper, frequency-domain analysis of linear exponentially damped systems subjected to arbitrary initial conditions is studied. The standard Discrete Fourier Transform (DFT) procedure combined with Fast Fourier Transform (FFT) algorithms is applied to compute dynamic responses, after transforming the original motion equations subjected to non-zero initial conditions into new ones with completely null initial conditions by using the pseudo-force approach. A multi-degree-of-freedom (MDOF) system and a continuum system with exponential damping are considered as the illustrative problems. The accuracy of the proposed method is evaluated by comparing the results with those obtained from Simulink based on the state-space method.

The behaviour of large gas bubbles in a liquid bath and the mechanisms of splash generation due to gas bubble rupture in high-intensity bath smelting furnaces were investigated by means of physical and mathematical (CFD) modelling techniques. In the physical modelling work, a two-dimensional Perspex model of the pilot plant furnace at CSIRO Process Science and Engineering was established in the laboratory. An aqueous glycerol solution was used to simulate liquid slag. Air was injected via a submerged lance into the liquid bath and the bubble behaviour and the resultant splashing phenomena were observed and recorded with a high-speed video camera. In the mathematical modelling work, a two-dimensional CFD model was developed to simulate the free surface flows due to motion and deformation of large gas bubbles in the liquid bath and rupture of the bubbles at the bath free surface. It was concluded from these modelling investigations that the splashes generated in high-intensity bath smelting furnaces are mainly caused by the rupture of fast rising large gas bubbles. The acceleration of the bubbles into the preceding bubbles and the rupture of the coalescent bubbles at the bath surface contribute significantly to splash generation.

Silicon nitride bonded silicon carbide ( Si 3 N 4- SiC ) refractories are commonly used as the sidewall of aluminum electrolysis cells. They have to withstand an extremely corrosive molten electrolyte bath for long periods. The sidewall is normally protected with a layer of solidified electrolyte (called frozen ledge), which is sensitive to the thermal conductivity of the sidewall. In this work, through review of the literature on modeling methods for predicting the effective thermal conductivity of dense composites and porous materials, some selected methods were applied to calculate the effective thermal conductivity of Si 3 N 4- SiC refractories. The model predictions were compared with the thermal conductivity of a commercial Si 3 N 4- SiC refractory measured by using laser flash technique. The present study showed that, due to multi-phase nature and complex microstructure of Si 3 N 4- SiC refractories, most of the selected modeling methods individually do not give satisfactory predictions in one step. Recursive applications of one method or combinations of different methods are capable of giving satisfactory predictions.

The kinetics of slag metal reactions are complex and often transient, in the sense that interfacial area, the equilibrium driving force, temperature gradients, and fluid properties are changing with time. This highly transient behavior is challenging to model using simple ordinary differential equations, and new theoretical approaches must be developed to deal with the complexity associated with these systems. Three examples from recent studies are described to illustrate methods of analyzing transient behavior. The first is desulfurization of steel in ladle metallurgy where the equilibrium driving force is changing with time, and the second is the case of reacting droplets in oxygen steelmaking where “bloating” of the droplet has a dramatic effect on the kinetics. The third is in the case of reactions between an alloy droplet and slag that result in large changes in interfacial area due to surface tension driven flows.

In basic oxygen steelmaking, the major portion of the refining is realized through reactions between metal droplets and slag. The residence time of metal droplets in the slag crucially influences the productivity. A model for the prediction of trajectory and residence time of metal droplets in slags has been developed based on mechanics and chemical kinetics principles. When there is no decarburization, analysis of the ballistic motion of metal droplets in the slag predicts very short residence times (

Numerical experiments were performed on fluid flow and heat transfer in 107-tonne steel ladles by 3-step implementations of numerical models. In the first step, a 1-dimensional numerical model was used to predict heat conduction fluxes through the ladle wall, bottom and top slag layer. In the second step, by means of computational fluid dynamics (CFD) modelling and employing the predicted heat loss fluxes as thermal boundary conditions, a 2-dimensional CFD model was applied to simulate natural convection in steel ladles during the holding period before teeming. In the third step, a 3-dimensional CFD model was implemented to further simulate fluid dynamics in the same ladles with drainage flows during teeming. Using these mathematical numerical models, the bulk cooling rate of the steel melt, the extent of thermal stratification during holding and the steel stream temperature during teeming were investigated for 2 types of 107-tonne steel ladles lined, respectively, with alumina and spinel in walls. In these investigations, the following 4 parameters were considered: (i)ladle lining inside surface (hot-face) temperature before tapping, (ii)top slag layer thickness, (iii) holding time and (iv) teeming rate. An important result of these investigations is that the concerned parameters all significantly influence the steel stream temperature during teeming, and the differences in teeming stream temperatures among different ladles, caused by these parameters, can be up to 20 deg C, which may be essential to temperature control in tundishes during continuous casting.

The similarity between steel ladles and hot-water models regarding natural convection phenomena has been systematically analysed through examination of the numerical solutions of turbulent Navier-Stokes partial differential equations governing the phenomena in question. The numerical solutions have been obtained by using a computational fluid dynamics (CFD) simulation method. Key similarity criteria for non-isothermal physical modelling of steel ladles with hot-water models have been derived as Fr m =Fr p and (βΔT) m =(βΔT) p where the subscripts m and p stand for the water model and the prototype steel ladle, respectively. Accordingly, appropriate conditions fulfilling the above criteria, such as model size, water temperature, time scale factor and the scale factor of boundary heat loss fluxes, have been proposed and discussed. As a result, water models with geometry scales between 1/5 and 1/3 and using hot-water of temperature higher than 45°C are appropriate for simulating natural convection phenomena in steel ladles.

A 1/4-scale hot-water model of industrial 107-tonne steel ladles was established in the laboratory. With this physical model, thermal stratification phenomena due to natural convection in steel ladles during the holding period before casting were investigated. By controlling the cooling intensity of the water model to correspond to the heat loss rate of steel ladles, which is governed by dimensionless numbers Fr and βΔT, temperature distributions in the water model can simulate those in the steel ladles. Consequently, the temperature profile in the hot-water bath in the model can be used to deduce the thermal stratification phenomena in liquid steel bath in the ladles. In addition, mathematical simulations on fluid flow and heat transfer both in the water model and in the prototype steel ladle were performed using a computational fluid dynamics (CFD) numerical method. The CFD model was validated against temperatures measured in the water model. Comparisons between mathematically simulated temperature profiles in the prototype steel ladle and those physically simulated by scaling-up the measured temperature profiles in the water model showed a good agreement. Therefore, it can be concluded that, as long as accurate heat loss information is known, it is feasible to use a 1/4-scale water model to non-isothermally simulate fluid flow and heat transfer in steel ladles during the holding period before casting.