706 results on '"Y. Y. Yan"'
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2. Study of the effect of dipole interactions on hyperthermia heating the cluster composed of superparamagnetic nanoparticles
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R. Fu, Y. Y. Yan, and C. Roberts
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Physics ,QC1-999 - Abstract
In the present work, we investigate the effect of dipole interactions on hyperthermia heating the cluster composed of multi superparamagnetic nanoparticles via time-quantified Monte Carlo simulation. The dynamic hysteresis loop area of non-interacting particles calculated by a modified Rosensweig’s model is shown to be proportional to the field frequency. The inverse of the total number of Monte Carlo steps per field cycle is considered as a computational frequency in our modelling. By comparing the two proportionality constants gained from the simulation and from the Rosensweig’s model, respectively, the time scale of one Monte Carlo step is estimated. The shape of the cluster is characterised by treating it as an equivalent ellipsoid. When the morphology of cluster is highly anisotropic such in a chain and cylinder, dipole interactions align the moments of the particles to the morphology anisotropy axis of the cluster. The strength of such alignment depends on the magnitude of morphology anisotropy of the cluster. The alignment helps improve heating capability of the chain and cylinder clusters at the most angles between the field direction and morphology anisotropy axis. However, when the field direction is away from the axis too much, the high energy barrier will hamper the cluster to maintain the magnetization, leading to a reduced heating efficiency. Once the cluster loses its morphology anisotropy (i.e. cube), the influence of dipole interactions on hysteresis losses is reduced to the minimum; the probability to obtain an improved heating becomes very low no matter with the type of particle arrangement.
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- 2015
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3. EHD ENHANCED HEAT EXCHANGERS: NEW CHALLENGING EQUIPMENT FOR RENEWABLE ENERGY APPLICATIONS
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Y. Y. Yan, Tassos G. Karayiannis, Michael W. Collins, P. H. G. Allen, R. S. Neve, and R. K. Al-Dadah
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- 2023
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4. Periarticular calcifications
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Y Y, Yan, Y N Bin, Dous, H A, Ouellette, P L, Munk, N, Murray, P I, Mallinson, and M A, Sheikh
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Diagnosis, Differential ,Osteoarthritis ,Calcinosis ,Humans ,Radiology, Nuclear Medicine and imaging - Abstract
Periarticular calcification and ossification is a frequent finding on imaging and may sometimes pose a diagnostic challenge. The differential diagnoses for this radiological finding are wide and can be classified into broad groups such as idiopathic, developmental, trauma, burns, infection, tumor, connective tissue disease, crystalline, metabolic, vascular, and foreign bodies. With careful consideration of the clinical and imaging findings as well as awareness of mimickers of periarticular mineralization, the list of differential diagnoses can be narrowed down. This article aims to review the clinical-radiologic findings of periarticular calcified or ossified lesions with relevant imaging illustrations.
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- 2021
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5. Identification of hub genes and molecular subtypes in COVID-19 based on WGCNA
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R-W, Hu, C, Liu, Y-Y, Yan, and D, Li
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Biomarkers, Tumor ,COVID-19 ,Genetic Variation ,Humans ,Oligonucleotide Array Sequence Analysis - Abstract
The heterogeneity of clinical manifestations and mortality rates in Coronavirus disease 2019 (COVID-19) patients may be related to the existence of molecular subtypes in COVID-19. To improve current management, it is essential to find the hub genes and pathways associated with different COVID-19 subtypes.The whole-genome sequencing information (GSE156063, GSE163151) of nasopharyngeal swabs from normal subjects and COVID-19 patients were downloaded from the Gene Expression Omnibus (GEO) database. The molecular subtypes of patients with COVID-19 were classified using the "consistent clustering" method, and the specific genes associated with each subtype were found. Differentially expressed genes (DEGs) were screened between normal subjects and COVID-19 patients; the Weighted gene co-expression network analysis (WGCNA) method was used to find the key module genes of COVID-19 patients. Subtype-specific, differentially expressed and module-related genes were collected and intersected. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were carried out and protein-protein interaction (PPI) networks were generated. The pathways enriched in COVID-19 subtypes were analyzed by gene set variation analysis (GSVA).Patients with COVID-19 were divided into three subtypes, and there was no significant difference in gender and age distribution between subtypes. 82 differential gene pathways were screened between Subtypes I and II, 131 differential gene pathways were screened between Subtypes I and III, and 107 differential gene pathways were screened between Subtypes II and III. Finally, 44 differentially expressed key genes were screened, including 11 hub genes (RSAD2, IFIT1, MX1, OAS1, OAS2, BST2, IFI27, IFI35, IFI6, IFITM3, STAT2).There are significant differences in gene activation and pathway enrichment among different molecular subtypes of COVID-19, which may account for the heterogeneity in clinical presentation and the prognosis of patients.
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- 2021
6. Calculation of Structural Response and Response Sensitivity with Improved Substructuring Method
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J. J. Li, G. J. Yang, S. Weng, and Y. Y. Yan
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- 2020
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7. [Analysis of factors related to recanalization of intramural hematoma-type carotid artery dissection]
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Y, Huang, P J, Hui, Y F, Ding, Y Y, Yan, M, Liu, L J, Kong, C H, Hu, and Q, Fang
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Aortic Dissection ,Hematoma ,Carotid Arteries ,Treatment Outcome ,Humans ,Carotid Stenosis ,Retrospective Studies - Published
- 2020
8. Active ingredients of
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Y Y, Yan, Q, Zhang, B, Zhang, B, Yang, and N M, Lin
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Pancreatic Neoplasms ,Lactones ,Cell Movement ,Plant Extracts ,Cell Line, Tumor ,Humans ,Sesquiterpenes, Eudesmane ,Apoptosis ,Inula ,Antineoplastic Agents, Phytogenic ,Sesquiterpenes ,Cell Line ,Cell Proliferation - Abstract
Isoalantolactone is one of the major active ingredients from
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- 2019
9. Active ingredients of Inula helenium L. exhibits similar anti-cancer effects as isoalantolactone in pancreatic cancer cells
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Y. Y. Yan, Q. Zhang, B. Zhang, B. Yang, and N. M. Lin
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Isoalantolactone is one of the major active ingredients from Inula helenium L. However, it is low cost-effective to isolate isoalantolactone from Inula helenium L. In this study, we optimized the extraction strategy and obtained a mixture of active ingredients with exact proportion (termed as F35), which were alloalantolactone, alantolactone and isoalantolactone at the ratio of 1/5/4 respectively. The anti-tumor activity of F35 was compared with isoalantolactone on pancreatic cancer cells. As a result, F35 showed nearly the same anti-proliferation activity as isoalantolactone in two cell lines. Both F35 and isoalantolactone could induce mitochondrion-related apoptosis at the concentration of 6 μg/ml. In addition, F35 inhibited colony-formation and migration of PANC-1 and SW1990 cells. To conclude, F35 exhibited similar anti-proliferation and anti-migration effect as isoalantolactone on two pancreatic cancer cell lines, suggesting that alantolactone or alloalantolactone might have comparable anti-tumor effect as isoalantolactone.
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- 2019
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10. [Individualized vancomycin dosing for a patient diagnosed as severe acute pancreatitis with concurrent extracorporeal membrane oxygenation and continuous veno-venous hemofiltration therapy: a case report]
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N, He, Y Y, Yan, Y Q, Ying, M, Yi, G Q, Yao, Q G, Ge, and S D, Zhai
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Adult ,Extracorporeal Membrane Oxygenation ,Pancreatitis ,Vancomycin ,Critical Illness ,Humans ,Female ,Hemofiltration ,Anti-Bacterial Agents - Abstract
Pharmacokinetic parameters can be significantly altered for acute kidney injury (AKI), extracorporeal membrane oxygenation (ECMO) and continuous veno-venous hemofiltration therapy (CVVH). Here we reported a case of individualized vancomycin dosing for a patient diagnosed as severe acute pancreatitis treated with concurrent ECMO and CVVH. A 65 kg 32-year-old woman was admitted to hospital presented with severe acute pancreatitis (SAP), respiratory failure, metabotropic acidosis and hyperkalemia. She was admitted to intensive care unit (ICU) on hospital day 1 and was initiated on CVVH. She progressed to multiple organ dysfunction syndrome (MODS) and acute respiratory distress syndrome (ARDS) on ICU day 2, and veno-venous ECMO was instituted. Several catheters were inserted into the body to support ECMO, CVVH and pulse indicator continuous cardiac output (PiCCO), so vancomycin was prescribed empirically on ICU day 3 for prevention of catheter-related infection. Given the residual renal function and continuous hemofiltration intensity on day 3, vancomycin bolus of 1 000 mg was prescribed, followed by a maintenance dose of 500 mg every 8 hours. On ICU day 4, a vancomycin trough serum concentration of 14.1 mg/L was obtained before the fourth dose, which was within the target range of 10-20 mg/L. By ICU day 7, vancomycin dosage was elevated to 1.0 g every 12 hours because of aggravated infection and improved kidney function. On ICU day 14, a vancomycin trough serum concentration of 17 mg/L was obtained. Her white blood cell (WBC) and neutrophil percentage (Neut%) dropped to the normal level by ICU day 19. This vancomycin regimen was successful in providing a target attainment of trough serum concentration ranging from 10-20 mg/L quickly and in controlling infection-related symptoms and signs properly. With the help of this case report we want to call attention to the clinically significant alteration in vancomycin pharmacokinetics among critically ill patients. Individualized vancomycin dosing regimens and therapeutic drug monitoring are necessary for critically ill patients receiving CVVH and ECMO to ensure that the target serum vancomycin levels are reached to adequately treat the infection and avoid nephrotoxicity.
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- 2018
11. [Sudden asphyxia of foreign body in trachea and bronchus: experience from 3 cases]
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X, Wen, Y L, Song, D M, Wang, Y N, Shi, and Y Y, Yan
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- 2018
12. [Effect analysis of 60 cases of modified septoplasty]
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Y B, Zhou, Y Y, Yan, and F, Yu
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- 2018
13. Relationship between Blood Acetaldehyde Concentration and Psychomotor Function of Individuals with Different ALDH2 Genotypes after Alcohol Consumption
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Y, Ye, F, Chen, H, Wu, S N, Lan, L R, Jiang, K K, Dai, Y Y, Yan, L, Yang, and L C, Liao
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Polymorphism, Genetic ,Alcohol Drinking ,Ethanol ,Genotype ,Aldehyde Dehydrogenase, Mitochondrial ,Humans ,Acetaldehyde ,Aldehyde Dehydrogenase ,Aldehyde Oxidoreductases ,Psychomotor Performance - Abstract
Objective To explore the change rules of blood ethanol and blood acetaldehyde concentration, the impairment of psychomotor functions of different acetaldehyde dehydrogenase (ALDH) 2 genotype individuals after alcohol consumption and the relationship among them. Methods The不同ALDH2基因型个体饮酒后血乙醛浓度与精神运动功能的关系.目的 探索不同乙醛脱氢酶(aldehyde dehydrogenase,ALDH)2基因型个体饮酒后血乙醇和血乙醛浓度变化规律、精神运动功能损害及其之间的联系。 方法 采用SNaPshot法医毒理学;乙醇;乙醛;乙醛脱氢酶;多态性;精神运动功能.
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- 2018
14. [Correlation of Genetic Polymorphism, Alcoholic Beverage Type and Ethanol Metabolism]
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Y, Ye, F, Chen, X, Lu, H, Wu, Q, Lu, Lei, Shi, Y Y, Yan, L, Yang, and L C, Liao
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Male ,China ,Polymorphism, Genetic ,Alcohol Drinking ,Ethanol ,Genotype ,Alcoholic Beverages ,Aldehyde Dehydrogenase, Mitochondrial ,Alcohol Dehydrogenase ,Acetaldehyde ,Aldehyde Dehydrogenase ,Polymorphism, Single Nucleotide ,Alcoholism ,Gene Frequency ,Humans ,Genetic Predisposition to Disease - Abstract
To explore the effects ofA total of 81 volunteers were selected. The genotypes ofThere were no differences in the value ofThe ethanol metabolism is associated with the related gene polymorphism, which is barely affected by alcoholic beverage type.
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- 2017
15. A study on the constraints of implementing Information and Communication Technology (ICT) in Malaysian Construction Industry
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F Y Y Yan, Tien-Choon Toh, K L Lim, Y L Lew, and L P Yow
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Engineering management ,Construction industry ,Information and Communications Technology ,Business - Abstract
Information and Communication Technology (ICT) refers to a combination of hardware, software and communication facilities. Often, ICT is introduced to equip construction stakeholders with information and analytical tools for a better control throughout the entire construction delivery process. The aim of this study is to investigate the issues relating to implementation of ICT in Malaysian construction industry with the objectives of: (i) to identify the benefits of adopting ICT in construction industry; (ii) to determine the constraints of implementing ICT in construction industry; and (iii) to identify the methods to encourage construction industry in adopting ICT. A questionnaire survey was conducted in Johor and Klang Valley of Malaysia, a total of 70 completed questionnaires were collected from contractors and quantity surveying consultation firm. Based on the analysis conducted, the top three benefits of adopting ICT in Malaysian construction industry ranked by the respondents are improvement on accuracy of measurement works, minimization on usage of paper by digitalization and allowed rapid sharing of information among project team. The barriers in implementing ICT in Malaysian construction industry identified included unaffordable initial capital and long term investment required, difficulties encountered to recruit capable and trustworthy in-house IT specialist, and security issues on confidential issues. Training and vendor’s efforts to improve their software have been agreed as the most achievable and practical methods to encourage ICT uptake. This study had explore the implementation and acceptance level of ICT in Malaysian construction industry. The views from both contractor and quantity surveying consultation firm were revealed. The findings from this study could be used as the baseline for future development of ICT in the local construction industry.
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- 2019
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16. Breakup of the proton halo nucleus 8B near barrier energies
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L. Yang, C. J. Lin, H. Yamaguchi, A. M. Moro, N. R. Ma, D. X. Wang, K. J. Cook, M. Mazzocco, P. W. Wen, S. Hayakawa, J. S. Wang, Y. Y. Yang, G. L. Zhang, Z. Huang, A. Inoue, H. M. Jia, D. Kahl, A. Kim, M. S. Kwag, M. La Commara, G. M. Gu, S. Okamoto, C. Parascandolo, D. Pierroutsakou, H. Shimizu, H. H. Sun, M. L. Wang, F. Yang, and F. P. Zhong
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Science - Abstract
Halo-structured nuclei are examples of many-body open quantum system. Here the authors use a complete kinematics measurement and find an elastic breakup of proton halo nucleus 8B.
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- 2022
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17. Growth and leaf gas exchange in Populus euphratica across soil water and salinity gradients
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Ming Han, B. Yu, Y. Y. Yan, J. Y. Li, Junguo Li, and C. Y. Zhao
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biology ,Physiology ,Chemistry ,Plant Science ,biology.organism_classification ,Photosynthesis ,Salinity ,Horticulture ,Seedling ,Botany ,Soil water ,Shoot ,Chlorophyll fluorescence ,Populus euphratica ,Water use - Abstract
Soil water and salinity conditions of the riparian zones along the Tarim River, northwest China, have been undergoing alterations due to water use by human or climate change, which is expected to influence the riparian forest dominated by an old poplar, Populus euphratica. To evaluate the effects of such habitat alterations, we examined photosynthetic and growth performances of P. euphratica seedlings across experimental soil water and salinity gradients. Results indicated that seedlings were limited in their physiological performance, as evidenced by decreases in their height and biomass, and the maximal quantum yield of photosystem II (PSII) photochemistry (Fv/Fm), the effective quantum-use efficiency of PSII (Fv′/Fm′), and photochemical quenching (qP) under mild (18% soil water content, SWC; 18.3 g kg−1 soil salt content, SSC) and moderate (13% SWC, 22.5 g kg−1 SSC) water or salinity stress. However, seedlings had higher root/shoot ratio (R/S), increased nonphotochemical quenching (NPQ), and water-use efficiency (WUE) relative to control under such conditions. Under severe (8% SWC, 27.9 g kg−1 SSC) water or salinity stress, P. euphratica seedlings had only a fifth of biomass of those under control conditions. It was also associated with damaged PSII and decreases in WUE, the maximal net photosynthetic rate (P Nmax), light-saturation point (LSP), and apparent quantum yield (α). Our results suggested that the soil conditions, where P.euphratica seedlings could grow normally, were higher than ∼ 13% for SWC, and lower than ∼22.5 g kg−1 for SSC, the values, within the seedlings could acclimate to water or salinity stress by adjusting their R/S ratio, improving WUE to limit water loss, and rising NPQ to dissipate excessive excitation energy. Once SWC was lower than 8% or SCC higher than ∼28 g kg−1, the seedlings suffered from the severe stress.
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- 2013
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18. [Damage-associated molecular patterns and liver failure]
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Y Y, Yan, S, Lin, and Y Y, Zhu
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Histones ,Receptors, Pattern Recognition ,Interleukin-18 ,Animals ,Humans ,HMGB1 Protein ,Liver Failure ,Mitochondria - Abstract
Damage-associated molecular patterns (DAMPs) are a series of intracellular molecules with immunoregulatory activity which are released by the damaged or activated cells and can induce autoimmunity or immune tolerance via pattern recognition receptors. At present, the DAMPs which have been discovered include extracellular histone, high-mobility group box-1, chromosomal deoxyribonucleic acid, interleukin-18, interleukin-32, uric acid, and mitochondrial transcription factors. The discovery of DAMPs and clarification of their mechanisms of action help to know the pathophysiological process of liver failure and provide new thoughts for the diagnosis, prevention, and treatment of liver failure. This article briefly summarizes the concept of DAMPs and their mechanisms of action in the development and progression of liver failure.
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- 2016
19. miR-143 is involved in endothelial cell dysfunction through suppression of glycolysis and correlated with atherosclerotic plaques formation
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R-H, Xu, B, Liu, J-D, Wu, Y-Y, Yan, and J-N, Wang
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MicroRNAs ,Endothelial Cells ,Humans ,Atherosclerosis ,Glycolysis ,Plaque, Atherosclerotic - Abstract
Atherosclerosis is recognized as a chronic inflammatory disease leading to hardening of the vessel wall and narrowing of arteries. Endothelial cells (ECs) exhibit highly active glycolysis, the dysfunction of which leads to accumulation of lipids in the arterial wall and formation of atherosclerotic plaque.qRT-PCR was performed to compare the deregulated miR-143 between atherosclerotic plaque and normal vessel tissues. The direct target of miR-143 was verified by Western blot and luciferase assay. The metabolic enzymes in atherosclerotic plaque and normal vessel tissues were measured. HUVECs were transfected with miR-143 precursor or control microRNAs, and glucose uptake, lactate production, intracellular ATP, and oxygen consumption were measured.In this study, we report a correlation between up-regulated miR-143, EC dysfunction, and atherosclerotic plaque formation. The glycolysis rate was significantly elevated in ECs, which show relatively low levels of miR-143. Importantly, miR-143 was upregulated in clinical atherosclerotic plaque samples compared with healthy arteries, suggesting that miR-143 might play important roles in the atherosclerotic plaque formation. Moreover, mRNA levels of key enzymes of glycolysis, such as HK2, LDHA, and PKM2 are significantly down-regulated in the atherosclerotic plaque samples. Overexpression of miR-143 in HUVECs suppresses glycolysis through direct targeting of HK2, leading to EC dysfunction. Restoration of HK2 expression rescues glycolysis in miR-143-overexpressing HUVECs.This study provides further insight into the metabolic mechanisms involved in atherosclerotic plaque formation due to microRNAs.
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- 2016
20. [Overexpression of Keap1 inhibits the cell proliferation and metastasis and overcomes the drug resistance in human lung cancer A549 cells]
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X, Weng, Y Y, Yan, Y H, Tong, Y, Fan, J M, Zeng, L L, Wang, and N M, Lin
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Gene Expression Regulation, Neoplastic ,Kelch-Like ECH-Associated Protein 1 ,Lung Neoplasms ,A549 Cells ,Drug Resistance, Neoplasm ,NF-E2-Related Factor 2 ,Humans ,Antineoplastic Agents ,Transfection ,Deoxycytidine ,Gemcitabine ,Carboplatin ,Cell Proliferation - Abstract
To investigate the effect of Keap1-Nrf2 pathway on cell proliferation, metastasis and drug resistance of human lung cancer A549 cell line.A549-Keap1 cell line, constantly expressing wild type Keap1, was established by lentiviral transfection. Real-time RT-PCR and western blot were used to determine the expression of Nrf2 and its target gene in A549 cells. Sulforhodamine B (SRB) assay, flow cytometry, colony formation assay, transwell assay, and cell wound-healing assay were performed to explore the effect of wild type Keap1 expression on the proliferation, invasion, migration and drug resistance of A549 cells.Over-expressed Keap1 decreased the expression of Nrf2 protein and the mRNA level of its downstream target genes and inhibited the ability of cell proliferation and clone formation of A549 cells. Keap1 overexpression induced G0/G1 phase arrest. The percentage of A549-Keap1 cells in G0/G1 phase was significantly higher than that of A549-GFP cells (80.2±5.9)% vs. (67.1±0.9%)(P0.05). Compared with the invasive A549-Keap1 cells (156.33±17.37), the number of invasive A549-GFP cells was significantly higher (306.67±22.19) in a high power field. Keap1 overexpression significantly enhanced the sensitivity of A549 cells to carboplatin and gemcitabine (P0.01). The IC50s of carboplatin in A549-Keap1 and A549-GFP cells were (52.1±3.3) μmol/L and (107.8±12.9) μmol/L, respectively. The IC50s of gemcitabine in A549-Keap1 and A549-GFP cells were (6.8±1.2) μmol/L and (9.9±0.5) μmol/L, respectively.Keap1 overexpression significantly inhibits the expression of Nrf2 and its downstream target genes, suppresses tumor cell proliferation and metastasis, and enhances the sensitivity of A549 cells to anticancer drugs.
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- 2016
21. [Expression of thrombus regulatory protein and myeloperoxidasein peripheral blood of adult with obstructive sleep apnea hypopnea syndrome]
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H C, Gong, F, Yu, Y Y, Yan, Y L, Jiao, and G J, Tan
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- 2016
22. One Alpha-hydroxycholecalciferol Improves Growth Performance, Tibia Quality, and Meat Color of Broilers Fed Calcium- and Phosphorus-Deficient Diets
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C. X. Shi, Y. Y. Yan, C. L. Wang, Liang Li, Q. Xie, J. L. Zhang, X. S. Dong, H. X. Qu, J. C. Han, Y. H. Cheng, X. L. Zhang, Y. L. Wang, and F. Liang
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Vitamin ,Veterinary medicine ,lcsh:Animal biochemistry ,chemistry.chemical_element ,Calcium ,Feed conversion ratio ,Article ,Growth Performance ,chemistry.chemical_compound ,Animal science ,medicine ,Tibia ,lcsh:QP501-801 ,lcsh:SF1-1100 ,Meal ,Meat Color ,Phosphorus ,Broiler ,food and beverages ,Small intestine ,medicine.anatomical_structure ,chemistry ,Animal Science and Zoology ,Tibia Quality ,One Alpha-hydroxycholecalciferol ,lcsh:Animal culture ,Food Science - Abstract
An experiment was conducted to evaluate the effects of one alpha-hydroxycholecalciferol (1α-OH D3) on growth performance, tibia quality, and skin and meat color in broilers fed calcium (Ca)- and phosphorus (P)-deficient corn-soybean meal diets. A total of 288 male Ross broilers, at 21 days of age, were randomly assigned to three treatments with eight cages per treatment. Three levels of 1α-OH D3 (0, 5, and 10 μg/kg) were added to a basal diet (0.50% Ca, 0.13% non-phytate phosphorus (NPP), and 0.35% total phosphorus (tP)) without vitamin D3. As a result of this study, the addition of 1α-OH D3 increased body weight gain (p
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- 2012
23. The characteristics of a microring resonator in optical waveguide displacement sensors
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Shubin Yan, Guoqing Jiang, Y Y Yan, Baohua Wang, Zhe Ji, and Wen Dong Zhang
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Coupling ,Materials science ,business.industry ,Resonance ,Condensed Matter Physics ,Laser ,Waveguide (optics) ,Displacement (vector) ,law.invention ,Resonator ,Optics ,Quality (physics) ,law ,General Materials Science ,Electrical and Electronic Engineering ,Whispering-gallery wave ,business - Abstract
Pumping a single-mode, tunable, external-cavity laser to excite the whispering gallery modes (WGM) of microring resonators (MRRs) allows the observation of a series of equidistant, wide free spectrum ranges (FSR). A frequency shift of an FSR can be used to feedback external changes, making MRRs very promising for high-sensitivity sensing. Furthermore, sensor performance is intimately related to the resonance condition and resonator quality factor, Q. In this paper, a novel displacement sensor composed of a microring resonator and a waveguide is presented. Materials selection is discussed. The two most important influencing factors, the optimized resonance condition and Q, are demonstrated especially. Based on mathematical analysis and finite-difference time-domain simulation, the optimized resonance is obtained when the radius and coupling distance are around 20μ and 0.2μ, respectively, with the FSR of the transmission spectrum about 13.6nm. Correspondingly, the ultimate Q is approximately 102 in the preliminary experiment.
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- 2008
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24. Effects of Sirtuin 1 on the proliferation and osteoblastic differentiation of periodontal ligament stem cells and stem cells from apical papilla
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Cui Shiman, Y.-R. Liu, Qingbin Zhang, Wei Cao, and Y.-Y. Yan
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musculoskeletal diseases ,0301 basic medicine ,Bone sialoprotein ,Periodontal ligament stem cells ,Periodontal Ligament ,Resveratrol ,Cell Line ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Sirtuin 1 ,Genetics ,Humans ,Osteopontin ,Molecular Biology ,Cell Proliferation ,biology ,Cell growth ,Stem Cells ,Cell Differentiation ,030206 dentistry ,General Medicine ,Cell biology ,030104 developmental biology ,chemistry ,Cell culture ,biology.protein ,Alkaline phosphatase ,Stem cell - Abstract
The function of SIRT1 in the proliferation and osteoblastic differentiation of dental stem cells is unclear. The aim of this study was to assess the roles of SIRT1 in these processes using periodontal ligament stem cells (PDLSCs) and stem cells from apical papilla (SCAPs). A defined concentration of resveratrol, an SIRT1 activator, or nicotinamide, an SIRT1 inhibitor, was administered to PDLSCs, SCAPs, and a mixed group of the two cell lines, and their effects on these processes analyzed. Cell proliferation was tested using microtitration with a tetrazolium dye (MTT). Alkaline phosphatase (ALP) activity, mineralization ability, and the expression of osteoblastic differentiation-associated genes were assessed as well. These studies demonstrated that resveratrol could promote cell proliferation of all three groups in a gradually increasing trend over time. In contrast, nicotinamide suppressed the proliferation of the three cell lines. The results also showed that the markers of osteoblastic differentiation: ALP activity, mineralization ability, and the expression levels of the osteoblastic genes ALP, osteopontin, osteocalcin, and bone sialoprotein, were enhanced in the groups with resveratrol treatment. In contrast, following addition of nicotinamide, ALP activity, mineralization ability, and the expression levels of the osteoblastic genes were down-regulated in the cells. Together, these results suggest that the SIRT1 activator and inhibitor compounds, resveratrol and nicotinamide, function at high efficiency in adjusting cell proliferation, and that SIRT1 is a powerful regulator of osteoblastic differentiation of PDLSCs and SCAPs. In addition, co-culture of the two cell lines could promote their abilities of proliferation and osteogenic differentiation.
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- 2016
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25. Rapid growth in nitrogen dioxide pollution over Western China, 2005–2013
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Y.-Z. Cui, J.-T. Lin, C. Song, M.-Y. Liu, Y.-Y. Yan, Y. Xu, and B. Huang
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Western China has experienced rapid industrialization and urbanization since the implementation of the National Western Development Strategies (the "Go West" movement) in 1999. This transition has affected the spatial and temporal characteristics of nitrogen dioxide (NO2) pollution. In this study, we analyze the trends and variability of tropospheric NO2 vertical column densities (VCDs) from 2005 to 2013 over Western China, based on a wavelet analysis on monthly mean NO2 data derived from the Ozone Monitoring Instrument (OMI) measurements. We focus on the anthropogenic NO2 by subtracting region-specific "background" values dominated by natural sources. We find significant NO2 growth over Western China between 2005 and 2013 (8.6 ± 0.9 % yr−1 on average, relative to 2005), with the largest increments (15 % yr−1 or more) over parts of several city clusters. The NO2 pollution in most provincial regions rose rapidly from 2005 to 2011 but stabilized or declined afterwards. The NO2 trends were driven mainly by changes in anthropogenic emissions, as confirmed by a nested GEOS-Chem model simulation and a comparison with Chinese official emission statistics. The rate of NO2 growth during 2005–2013 reaches 11.3 ± 1.0 % yr−1 over Northwestern China, exceeding the rates over Southwestern China (5.9 ± 0.6 % yr−1) and the three well-known polluted regions in the east (5.3 ± 0.8 % yr−1 over Beijing–Tianjin–Hebei, 4.0 ± 0.6 % yr−1} over the Yangtze River Delta, and −3.3 ± 0.3 % yr−1 over the Pearl River Delta). Additional socioeconomic analyses suggest that the rapid NO2 growth in Northwestern China is likely related to the fast developing resource- and pollution-intensive industries along with the "Go West" movement as well as relatively weak emission controls. Further efforts should be made to alleviate NOx pollution to achieve sustainable development in Western China.
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- 2015
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26. Improved simulation of tropospheric ozone by a global-multi-regional two-way coupling model system
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Y.-Y. Yan, J.-T. Lin, J. Chen, and L. Hu
- Abstract
Small-scale nonlinear chemical and physical processes over pollution source regions affect the global ozone (O3) chemistry, but these processes are not captured by current global chemical transport models (CTMs) and chemistry-climate models that are limited by coarse horizontal resolutions (100–500 km, typically 200 km). These models tend to contain large (and mostly positive) tropospheric O3 biases in the Northern Hemisphere. Here we use a recently built two-way coupling system of the GEOS-Chem CTM to simulate the global tropospheric O3 in 2009. The system couples the global model (at 2.5° long. × 2° lat.) and its three nested models (at 0.667° long. × 0.5° lat.) covering Asia, North America and Europe, respectively. Benefiting from the high resolution, the nested models better capture small-scale processes than the global model alone. In the coupling system, the nested models provide results to modify the global model simulation within respective nested domains while taking the lateral boundary conditions from the global model. Due to the "coupling" effects, the two-way system significantly improves the tropospheric O3 simulation upon the global model alone, as found by comparisons with a suite of ground (1420 sites from WDCGG, GMD, EMEP, and AQS), aircraft (HIPPO and MOZAIC), and satellite measurements (two OMI products). Compared to the global model alone, the two-way coupled simulation enhances the correlation in day-to-day variation of afternoon mean O3 with the ground measurements from 0.53 to 0.68, and it reduces the mean model bias from 10.8 to 6.7 ppb in annual average afternoon O3. Regionally, the coupled model reduces the bias by 4.6 ppb over Europe, 3.9 ppb over North America, and 3.1 ppb over other regions. The two-way coupling brings O3 vertical profiles much closer to the HIPPO (for remote areas) and MOZAIC (for polluted regions) data, reducing the tropospheric (0–9 km) mean bias by 3–10 ppb at most MOZAIC sites and by 5.3 ppb for HIPPO profiles. The two-way coupled simulation also reduces the global tropospheric column ozone by 3.0 DU (9.5 %, annual mean), bringing them closer to the OMI data in all seasons. Simulation improvements are more significant in the northern hemisphere, and are primarily a result of improved representation of urban-rural contrast and other small-scale processes. The two-way coupled simulation also reduces the global tropospheric mean hydroxyl radical by 5 % with enhancements by 5 % in the lifetimes of methyl chloroform (from 5.58 to 5.87 yr) and methane (from 9.63 to 10.12 yr), bringing them closer to observation-based estimates. Improving model representations of small-scale processes are a critical step forward to understanding the global tropospheric chemistry.
- Published
- 2015
- Full Text
- View/download PDF
27. Experimental Study on the Effect of Non-Uniform Inlet Velocity Profile on Internal Cooling in Rectangular Channels With Multi-Features
- Author
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John David Maltson, S. Huang, and Y. Y. Yan
- Subjects
Pressure drop ,Materials science ,Lumped capacitance model ,Analytical chemistry ,Reynolds number ,Heat transfer coefficient ,Mechanics ,Capacitance ,Physics::Fluid Dynamics ,symbols.namesake ,Pedestal ,Thermal ,Heat transfer ,symbols - Abstract
Experiments were conducted to investigate the overall thermal performance of rectangular channels with a non-uniform inlet velocity profile. Two test sections with multiple internal cooling features had been used. One test section was implemented with two circular staggered pin-fin arrays with different pin diameters. The other one was implemented with a combination of a staggered pin-fin array and a perforated blockage array. The average surface heat transfer coefficient of the pedestal and perforated blockage and the local distribution of heat transfer coefficient on endwall were measured by the lumped capacitance method and transient liquid crystal method, respectively. The pressure drop across each array was measured. The heat transfer coefficients were measured over the Reynolds number range from 9,000 to 17,000. The spanwise pitches of the upstream pin-fin arrays were 2.33 and 4.66 for the channel with the multiple pin-fin array and the channel with perforated blockage, respectively. The effect of a non-uniform velocity profile on local heat transfer pattern and row-resolved heat transfer coefficient has been investigated.Copyright © 2015 by ASME
- Published
- 2015
- Full Text
- View/download PDF
28. Perceptions of severe weather warnings in Hong Kong
- Author
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Y Y Yan and T F Wong
- Subjects
Atmospheric Science ,Severe weather ,Operations research ,business.industry ,Perception ,media_common.quotation_subject ,Environmental health ,Public education ,Psychology ,business ,media_common ,Mass media - Abstract
In this study 320 people in Hong Kong were interviewed to assess their understanding and perception of severe weather warnings. The majority of the respondents (72%) received warnings from mass media. Although 99.4% of the interviewees claimed they knew all the warning signals, results indicate that most of them have only a basic understanding of what they mean. The study revealed that the warnings often lack other important information, such as the time of issue, validity period and precautions to be taken. Only 31% of the respondents stated they would take precautions at the issue of warnings, although people aged over 60 tended to be well prepared for the onset of severe weather. Public education is necessary to promote people's understanding of the warnings and awareness of the risks of severe weather. Copyright © 2002 Royal Meteorological Society.
- Published
- 2002
- Full Text
- View/download PDF
29. Evaporation Heat Transfer and Pressure Drop of Refrigerant R-134a in a Plate Heat Exchanger
- Author
-
T.F. Lin and Y.-Y. Yan
- Subjects
Materials science ,Convective heat transfer ,Critical heat flux ,Mechanical Engineering ,Plate heat exchanger ,Thermodynamics ,Heat transfer coefficient ,Mechanics ,Condensed Matter Physics ,Mechanics of Materials ,Micro heat exchanger ,General Materials Science ,Plate fin heat exchanger ,Vapor-compression evaporation ,Nucleate boiling - Abstract
Plate heat exchangers (PHE) have been widely used in food processing, chemical reaction processes, and other industrial applications for many years. Particularly, in the last 20 years plate heat exchangers have been introduced to the refrigeration and air conditioning systems as evaporators or condensers for their high efficiency and compactness. Here, the evaporation heat transfer coefficient and pressure drop for refrigerant R-134a flowing in a plate heat exchanger were investigated experimentally in this study. Two vertical counterflow channels were formed in the exchanger by three plates of commercial geometry with a corrugated sine shape of a chevron angle of 60 deg. Upflow boiling of refrigerant R-134a in one channel receives heat from the hot downflow of water in the other channel. The effects of the mean vapor quality, mass flux, heat flux, and pressure of R-134a on the evaporation heat transfer and pressure drop were explored. The quality change of R-134a between the inlet and outlet of the refrigerant channel ranges from 0.09 to 0.18. Even at a very low Reynolds number, the present flow visualization of evaporation in a plate heat exchanger remains turbulent. It is found that the evaporation heat transfer coefficient of R-134a in the plates ismore » much higher than that in circular pipes and shows a very different variation with the vapor quality from that in circular pipes, particularly in the convective evaporation dominated regime at high vapor quality. Relatively intense evaporation on the corrugated surface was seen from the flow visualization. Moreover, the present data showed that both the evaporation heat transfer coefficient and pressure drop increase with the vapor quality. At a higher mass flux the pressure drop is higher for the entire range of the vapor quality but the evaporation heat transfer is clearly better only at the high quality. Raising the imposed wall heat flux was found to slightly improve the heat transfer, while at a higher refrigerant pressure, both the heat transfer and pressure drop are slightly lower. Based on the present data, empirical correlations for the evaporation heat transfer coefficient and friction factor were proposed.« less
- Published
- 1999
- Full Text
- View/download PDF
30. Enhancement of pool boiling heat transfer in a horizontal water layer through surface roughness and screen coverage
- Author
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Y. Y. Yan, T. F. Lin, and J. Y. Tsay
- Subjects
Fluid Flow and Transfer Processes ,Materials science ,Bubble ,Instrumentation ,Condensed Matter Physics ,Metal ,visual_art ,Boiling ,Heat transfer ,visual_art.visual_art_medium ,Surface roughness ,Composite material ,Layer (electronics) ,Nucleate boiling - Abstract
An experimental investigation was carried out to study the augmentation of heat transfer in saturated pool boiling of a liquid water layer on a heated horizontal stainless steel plate by roughing the surface and/or covering it with a single layer of stainless steel screen. The results were presented in terms of the boiling curves. Effects of various parameters – the surface roughness, liquid level and size of the stainless steel mesh on the boiling heat transfer were examined in detail. The measured data clearly indicated that a lowering of the liquid level from 60 to 5 mm in water depth causes heat transfer reduction. Roughing the surface was found to sig- nificantly enhance the heat transfer. Use a layer of metal screen to cover the heated surface was shown to substantially augment the heat transfer especially for a shallow water layer if the mesh size is comparable with the bubble departure diameter. Covering the rough surface with the metal mesh, however, reduced the heat transfer.
- Published
- 1996
- Full Text
- View/download PDF
31. Effects of a Chinese medical herbs complex on cellular immunity and toxicity-related conditions of breast cancer patients
- Author
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S. L. Chen, G. T. Shane, H. S. Lee, H. F. Chiu, S. R. Zhuang, J. H. Tsai, C.-K. Wang, You-Cheng Shen, Y. Y. Yan, and M. Y. Lee
- Subjects
medicine.medical_specialty ,Cellular immunity ,Angelica sinensis ,Neutrophils ,medicine.medical_treatment ,Anti-Inflammatory Agents ,Medicine (miscellaneous) ,Antineoplastic Agents ,Breast Neoplasms ,Placebo ,Protective Agents ,Gastroenterology ,Medication Adherence ,Cohort Studies ,Leukocyte Count ,Breast cancer ,Immune system ,Double-Blind Method ,Internal medicine ,medicine ,Leukocytes ,Cytotoxic T cell ,Humans ,Neoplasm Staging ,Chemotherapy ,Immunity, Cellular ,Nutrition and Dietetics ,biology ,business.industry ,Cancer ,Leukopenia ,Middle Aged ,medicine.disease ,biology.organism_classification ,Immunology ,Female ,Leukopoiesis ,business ,Carcinoma in Situ ,Drugs, Chinese Herbal - Abstract
Rose geranium (Pelargonium graveolens, Geraniaceae) has anti-cancer and anti-inflammatory properties, and promotes wound healing. Similarly,Ganoderma tsugae(Ganodermataceae),Codonopsis pilosula(Campanulaceae) andAngelica sinensis(Apiaceae) are traditional Chinese herbs associated with immunomodulatory functions. In the present study, a randomised, double-blind, placebo-controlled study was conducted to examine whether the Chinese medicinal herb complex, RG-CMH, which represents a mixture of rose geranium and extracts ofG. tsugae, C. pilosula and A. sinensis, can improve the immune cell count of cancer patients receiving chemotherapy and/or radiotherapy to prevent leucopenia and immune impairment that usually occurs during cancer therapy. A total of fifty-eight breast cancer patients who received chemotherapy or radiotherapy were enrolled. Immune cell levels in patient serum were determined before, and following, 6 weeks of cancer treatment for patients receiving either an RG-CMH or a placebo. Administration of RG-CMH was associated with a significant reduction in levels of leucocytes from 31·5 % for the placebo group to 13·4 % for the RG-CMH group. Similarly, levels of neutrophils significantly decreased from 35·6 % for the placebo group to 11·0 % for the RG-CMH group. RG-CMH intervention was also associated with a decrease in levels of T cells, helper T cells, cytotoxic T cells and natural killer cells compared with the placebo group. However, these differences between the two groups were not statistically significant. In conclusion, administration of RG-CMH to patients receiving chemotherapy/radiotherapy may have the capacity to delay, or ease, the reduction in levels of leucocytes and neutrophils that are experienced by patients during cancer treatment.
- Published
- 2011
32. LBM simulation of interfacial behaviour of bubbles flow at low Reynolds number in a square microchannel
- Author
-
Y. Y. Yan and Y. Q. Zu
- Subjects
Condensed Matter::Soft Condensed Matter ,Physics::Fluid Dynamics ,Coalescence (physics) ,Surface tension ,symbols.namesake ,Microchannel ,Materials science ,Lattice Boltzmann methods ,symbols ,Thermodynamics ,Reynolds number ,Mechanics ,Isothermal process - Abstract
Bubbles flow in a microchannel is an interfacial and surface tension dominated problem. The paper reports results of numerical modelling and simulation of interfacial behaviour of bubbles flow and coalescence in a square microchannel. The lattice Boltzmann method (LBM) is developed and applied to the simulation in which a simple linear function is applied to the order parameter to approximate the density within the interface of gas-liquid. The evolution of two isothermal air bubbles flowing through a water-filled microchannel at low Reynolds number and the interactions between the flow fields and the interface of gas-liquid are simulated and investigated numerically.
- Published
- 2009
- Full Text
- View/download PDF
33. Parasitic diseases of cultured marine finfishes and their surveillance in China
- Author
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T B, Yang, A P, Chen, W, Chen, A X, Li, and Y Y, Yan
- Subjects
China ,Fish Diseases ,Oceans and Seas ,Oviposition ,Parasitic Diseases, Animal ,Population Surveillance ,Fisheries ,Animals ,Aquaculture ,Ectoparasitic Infestations ,Protozoan Infections, Animal - Abstract
More than 40 species of marine fishes are cultured in China and a wide variety of parasites are reported as lethal pathogens of these fishes in culture conditions. In the case of net cages, the culture facilities provides a good substrate for monogenean eggs to become entangled and the intensive aggregation of fishes facilitates the transmission of parasites between hosts. Relatively thorough studies on parasitic pathogens of marine fishes in China predominately concern the ciliate Cryptocaryon irritans and capsalid monogeneans (mainly Benedenia sp. and Neobenedenia sp.). Although nearly all such reports are related to treatment procedures, no single method has proved to be adequate for the effective control of these parasitic pathogens in marine cultured fishes. The National Fisheries Technology Extension Center (NFTEC) has established surveillance systems to monitor the diseases of aquaculture, including the parasitic diseases of maricultured fishes. The national monitoring stations for diseases of cultured marine fishes are distributed in the coastal counties or cities and provide remote in situ diagnoses of diseased fishes. International cooperation and effort are required for the control of parasitic diseases of marine finfish because of both the increasing international trade of eggs (seed) and larvae and commercial products in terms of live marine finfishes, which can readily result in the transmission of pathogens.
- Published
- 2008
34. A Molecular Dynamics Simulation of Droplets Merging in Mist Flow of Flow Boiling Microchannel
- Author
-
C. Y. Ji and Y. Y. Yan
- Subjects
Physics::Fluid Dynamics ,Molecular dynamics ,Microchannel ,Chemistry ,Boiling ,Physics::Atomic and Molecular Clusters ,Mist ,Periodic boundary conditions ,Mechanics ,Dumbbell ,Flow boiling ,Merge (version control) ,Simulation - Abstract
The present paper is concerned with a molecular dynamics simulation of the behaviour of droplets merging in mist flow of flow boiling in microchannel. Two identical droplets were assigned in one simulation system and the process of their merging is investigated. The droplets are assumed to be composed of Lennards-Jones type molecules. Periodic boundary conditions are applied in three coordinate directions of a three-dimensional system, where there exist two liquid droplets and their vapour. The two droplets merge when they come within the prescribed small distance. The evolution of the merging process is simulated and presented. The merging of two droplets apart from each other at different initial distances is tested and the possible larger (or critical) non-dimensional distance, in which droplet merging can occur, is discussed. The evolution of the merging process is simulated numerically by employing the molecular dynamics (MD) method. In the present modelling, the molecules near the boundary of one liquid droplet thermally fluctuate into the range of attraction of the other droplet, forming a bridge to connect the two droplets. A dumbbell shape is then formed and thereafter an elliptic merged droplet. Eventually a larger merged spherical droplet appears in the system and is in equilibrium with its vapour phase. More realistic simulation system will be established to further the present preliminary results for application in mist flow of flow boiling in microchannel.Copyright © 2008 by ASME
- Published
- 2008
- Full Text
- View/download PDF
35. Numerical modelling of bubble coalescence and droplet separation
- Author
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Y. Y. Yan and Y. Q. Zu
- Subjects
Materials science ,Bubble ,Separation (aeronautics) ,Bubble coalescence ,Mechanics - Published
- 2007
- Full Text
- View/download PDF
36. Lattice Boltzmann simulation of vortices merging in a two-phase mixing layer
- Author
-
Y. Q. Zu and Y. Y. Yan
- Subjects
Surface tension ,Materials science ,HPP model ,Vertical direction ,Lattice Boltzmann methods ,Perturbation (astronomy) ,Chemical reactor ,Combustion chamber ,Computational physics ,Vortex - Abstract
Mixing layers are commonly observed in flow fields of many types of industrial equipment such as combustion chambers, chemical reactors, and fluid ejectors. It is important to effectively mix two co-flowing gaseous/fluids streams in such equipment. As the mixing of two fluids is an interface and surface tension dominated process, numerical simulations of the mixing process are generally very complex. The present study is concerned with using the lattice Boltzmann method (LBM) to study vertices merging in a two-dimensional two-phase spatial growing mixing layer. Different velocity perturbations are forced at the entrance of the flow field of a rectangular mixing layer; the initial interface between twophases is evenly distributed around the midpoint in a vertical direction. By changing the strength of surface tension and combinations of perturbation waves, the effects of surface tension and velocity perturbation on vortices merging are investigated. Some interesting phenomena, which have not occurred in a singlephase mixing layer, are observed and the corresponding mechanism is discussed.
- Published
- 2006
- Full Text
- View/download PDF
37. The Performance of Large-Scale PEM Fuel Cell With Interdigitated Flow Channels
- Author
-
Y. Y. Yan, C. T. Chang, H. R. Shiu, and Falin Chen
- Subjects
Pressure drop ,Diffusion layer ,Membrane ,Materials science ,Flow (psychology) ,Analytical chemistry ,Proton exchange membrane fuel cell ,Electrolyte ,Composite material ,Polarization (electrochemistry) ,Volumetric flow rate - Abstract
A large-scale polymer electrolyte membrane fuel cell (PEMFC) with novel interdigitated (or discontinuous) flow channel has been investigated experimentally. Interdigitated channel geometry has the advantages of effective water removal and higher reaction efficiency through forcing gas transport in the diffusion layer. In this study, multiple-Z type flow pattern has been adopted on the interdigitated channels. The active area of flow channel plate is 256 cm2 (16 cm × 16 cm). The channel width and depth are 1 mm and 0.8 mm respectively. The rib width is 1 mm. The performance of single PEM fuel cell with an interdigitated flow field is studied with appropriated operating conditions. The results demonstrated that the multiple-Z interdigitated flow channel has better performance compared with the conventional Z type by presented in the form of Current-Voltage (I-V) polarization curves. The pressure drop loss of multiple-Z interdigitated flow field increases about one time with the conventional one. The experimental results under the effects of gas humidification temperature and reactant gas flow rate, etc. have been comprehensively discussed in this work.Copyright © 2006 by ASME
- Published
- 2006
- Full Text
- View/download PDF
38. Analysis of a 3 kW PEM Fuel Cell Stack Developed by ITRI
- Author
-
Y. Y. Yan, F. Tsau, M. H. Tsai, H. S. Chu, and R. J. Shyu
- Subjects
Hydrogen storage ,Engineering ,Electricity generation ,Waste management ,Operating temperature ,Stack (abstract data type) ,business.industry ,Nuclear engineering ,Humidity ,Proton exchange membrane fuel cell ,Energy transformation ,business ,Efficient energy use - Abstract
A 3kW PEMFC power generation system is developed by Energy and Resources Laboratories in 2002. This system integrates hydrogen storage, fuel reformer, power conversion, hot water tank as well as a 3kW PEMFC stack. The power generation efficiency at 30% and total energy efficiency with hot water recovery at 67% are designed. The stack is key component of this system, and its performance is tested and analyzed before it is integrated into the system. This paper presents its performance in I-V polarization curves with controlling parameters such as fuel cell operating temperature, air humidity, hydrogen humidity and stoichimetric ratio of air. Detailed discussions are given for the effect of each parameter on stack’s performance.Copyright © 2004 by ASME
- Published
- 2004
- Full Text
- View/download PDF
39. The Influence of Air-Bleeding on Co-Poisoning of PEM Fuel Cell
- Author
-
Y. Y. Yan, L. Y. Sung, F. Chen, H. S. Chu, and R. J. Shyu
- Subjects
Electricity generation ,Catalytic reforming ,Waste management ,Chemistry ,Hydrogen fuel ,Nuclear engineering ,Proton exchange membrane fuel cell ,Regenerative fuel cell ,Direct-ethanol fuel cell ,Unitized regenerative fuel cell ,Anode - Abstract
The PEM fuel cell has broad applications such as stationary power generation, transportation power sources and portable power generators. From commercial considerations, most anodes of PEM fuel cells use reformate gas as their fuels. However, reformate gas will have small content of carbon monoxide (CO) which will seriously poison platinum (Pt) catalyst electrode, and result in cell performance degradation significantly. The anode air-bleeding method is a preferable way to solve this CO-poisoning problem due to its simplicity, low cost and effectiveness. In this study, a test PEM fuel cell (single cell, active area 5cm × 5 cm) is assembled, its anode fuel uses hydrogen with 52.7ppm CO. Air-bleeding method then is applied to investigate and analyze the influence of CO poisoning on the performance of this PEM fuel cell.Copyright © 2004 by ASME
- Published
- 2004
- Full Text
- View/download PDF
40. The Influence of Water and Thermal Conditions on the Performance of PEM Fuel Cell
- Author
-
H. S. Chu, F. S. Tsu, K. C. Tsay, F. Chen, R. J. Shyu, Y. Y. Yan, and L. Y. Sung
- Subjects
Hydrogen ,Waste management ,chemistry.chemical_element ,Proton exchange membrane fuel cell ,Humidity ,Direct-ethanol fuel cell ,Electrochemistry ,Cathode ,law.invention ,Anode ,chemistry ,Chemical engineering ,law ,Water content - Abstract
The conditions of water content in the proton exchange membrane fuel cell (PEMFC) are studied in this research. It is known that the hydrogen proton should accompany with water molecule in order to drift through the membrane from anode to cathode. This drift force will concern to the fuel cell performance. However, too much water content may result of flooding. When flooding appears, some catalyst surfaces may be covered with water and result of the catalysts inactive. This will reduce the electrochemical reaction rate. Furthermore, due to the water molecule will occupy the space, this will hinder the reactant molecules approaching to the catalyst. Therefore, the management of water for the fuel cells is very important. The performance can be optimized with a better control of cell conditions. Some important conditions that concern to the heat and water management are investigated. They include cell temperature, reactant flow rate, humidity and pressure. A standard single cell stack with active area of 25cm2 was set for this study.Copyright © 2003 by ASME
- Published
- 2003
- Full Text
- View/download PDF
41. Forced convection in joined rectangular grooves numerical simulation of PIV and LDA measurements
- Author
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I. Grant, Y.-Y. Yan, and A. Aroussi
- Subjects
Physics ,Computer simulation ,Mathematical model ,Turbulence ,business.industry ,Mechanics ,Forced convection ,Vortex ,Physics::Fluid Dynamics ,Optics ,Particle image velocimetry ,Anemometer ,Incompressible flow ,business - Abstract
The authors investigated the fluid motion in L-shaped geometries using a laser Doppler anemometer (LDA), particle image velocimetry (PIV), and computational techniques, in order to reveal details on the structure and stability of the trapped eddy system. The aim was to simulate the flows measured with the LDA and PIV and to assess the accuracy of the mathematical models used. The nonintrusive optical measurements of the fluid motion in joined rectangular grooves were numerically predicted using two models of turbulence. The structure of the vortex system within the geometries was determined, and its dependence on the aspect ratios of the groove was established. The performance of the turbulence models in simulating these complex flows is assessed. >
- Published
- 2002
- Full Text
- View/download PDF
42. A machine vision particle image velocimetry system for the monitoring opaque slurry motion
- Author
-
Y.-Y. Yan and Ian Grant
- Subjects
Physics::Fluid Dynamics ,Engineering ,Optics ,Particle image velocimetry ,Channel (digital image) ,Opacity ,business.industry ,Machine vision ,Slurry ,Two-phase flow ,business ,Flow measurement ,Open-channel flow - Abstract
The authors describe the application of a machine vision method to the monitoring of surface flow measurement. A white-light stroboscopic illumination was used to enable electronic, multiple-image capture of slurry surface behavior. Techniques for feature tracking are described and illustrated using drilling mud as the target fluid. In industrial applications the fluids are frequency opaque so that internal measurements by this method are not possible. Bulk flow quantities and internal velocities can be obtained by applying a transformation representing the relationship between the flow in a channel, surface velocities channel geometrical shape, and physical properties of fluid. In the present case, a channel with a square cross section was used to obtain this relationship. >
- Published
- 2002
- Full Text
- View/download PDF
43. Improved simulation of tropospheric ozone by a global-multi-regional two-way coupling model system.
- Author
-
Y. -Y. Yan, J. -T. Lin, J. Chen, and L. Hu
- Subjects
SIMULATION methods & models ,TROPOSPHERIC chemistry ,OZONE ,ATMOSPHERIC models ,MAGNETIC coupling - Abstract
Small-scale nonlinear chemical and physical processes over pollution source regions affect the global ozone (O
3 ) chemistry, but these processes are not captured by current global chemical transport models (CTMs) and chemistry-climate models that are limited by coarse horizontal resolutions (100-500 km, typically 200 km). These models tend to contain large (and mostly positive) tropospheric O3 biases in the Northern Hemisphere. Here we use a recently built two-way coupling system of the GEOS-Chem CTM to simulate the global tropospheric O3 in 2009. The system couples the global model (at 2.5° long. × 2° lat.) and its three nested models (at 0.667° long. × 0.5° lat.) covering Asia, North America and Europe, respectively. Benefiting from the high resolution, the nested models better capture small-scale processes than the global model alone. In the coupling system, the nested models provide results to modify the global model simulation within respective nested domains while taking the lateral boundary conditions from the global model. Due to the "coupling" effects, the two-way system significantly improves the tropospheric O3 simulation upon the global model alone, as found by comparisons with a suite of ground (1420 sites from WDCGG, GMD, EMEP, and AQS), aircraft (HIPPO and MOZAIC), and satellite measurements (two OMI products). Compared to the global model alone, the two-way coupled simulation enhances the correlation in day-to-day variation of afternoon mean O3 with the ground measurements from 0.53 to 0.68, and it reduces the mean model bias from 10.8 to 6.7 ppb in annual average afternoon O3 . Regionally, the coupled model reduces the bias by 4.6 ppb over Europe, 3.9 ppb over North America, and 3.1 ppb over other regions. The two-way coupling brings O3 vertical profiles much closer to the HIPPO (for remote areas) and MOZAIC (for polluted regions) data, reducing the tropospheric (0-9 km) mean bias by 3-10 ppb at most MOZAIC sites and by 5.3 ppb for HIPPO profiles. The two-way coupled simulation also reduces the global tropospheric column ozone by 3.0 DU (9.5 %, annual mean), bringing them closer to the OMI data in all seasons. Simulation improvements are more significant in the northern hemisphere, and are primarily a result of improved representation of urban-rural contrast and other small-scale processes. The two-way coupled simulation also reduces the global tropospheric mean hydroxyl radical by 5 % with enhancements by 5 % in the lifetimes of methyl chloroform (from 5.58 to 5.87 yr) and methane (from 9.63 to 10.12 yr), bringing them closer to observation-based estimates. Improving model representations of small-scale processes are a critical step forward to understanding the global tropospheric chemistry. [ABSTRACT FROM AUTHOR]- Published
- 2015
- Full Text
- View/download PDF
44. [Untitled]
- Author
-
Y. Y. Yan, Yang Yang, and Haibo Qiu
- Subjects
medicine.medical_specialty ,business.industry ,Inflammatory response ,Emergency medicine ,medicine ,Rabbit model ,Lung protective ventilation ,Acute respiratory distress ,Critical Care and Intensive Care Medicine ,Intensive care medicine ,business ,Diffuse alveolar damage - Published
- 2005
- Full Text
- View/download PDF
45. Zinc-alleviating effects on iron-induced phytotoxicity in roots of Triticum aestivum
- Author
-
T. Ma, X. H. Duan, Y. Y. Yang, J. Yao, and T. P. Gao
- Subjects
antioxidative enzymes ,lipid peroxidation ,reactive oxygen species ,root growth ,Biology (General) ,QH301-705.5 ,Plant ecology ,QK900-989 - Abstract
The mechanisms of growth inhibition and antioxidative response were investigated in wheat roots exposed to 300 μM iron together with different zinc concentrations (0, 50, and 250 μM). All Zn concentrations decreased Fe content but increased Zn content in the roots and leaves of Fe-treated seedlings. Compared with Fe stress alone, 50 or 250 μM Zn + Fe treatment stimulated root growth, and increased cell viability but decreased malondialdehyde content, which were correlated with the decreases of total and apoplastic hydrogen peroxide and superoxide anion radical (O2 .-) content along with apoplastic hydroxyl radical content. Generation of O2 .- in response to 10 μM diphenylene iodonium suggested that NADPH oxidase activity was lower in Zn + Fe-treated roots than in other roots. In addition, cell wallbound peroxidase, diamine oxidase, and polyamine oxidase in Fe-treated roots were insensitive to Zn addition. Further study showed the stimulation of total superoxide dismutase and glutathione reductase (GR) activities as well as apoplastic catalase, ascorbate peroxidase, and GR in Zn + Fe-stressed roots in comparison with Fe-alone-treated ones. Taken together, Zn could alleviate iron-inhibitory effect on root growth, which might be associated with the decrease of lipid peroxidation, the increase of cell viability and the reductions of reactive oxygen species generation.
- Published
- 2017
- Full Text
- View/download PDF
46. Effects of exogenous phytase and xylanase, individually or in combination, and pelleting on nutrient digestibility, available energy content of wheat and performance of growing pigs fed wheat-based diets
- Author
-
Y. Y. Yang, Y. F. Fan, Y. H. Cao, P. P. Guo, B. Dong, and Y. X. Ma
- Subjects
Digestible and Metabolizable Energy ,Feed Enzymes ,Growing Pigs ,Pelleting ,Wheat ,Performance ,Animal culture ,SF1-1100 ,Animal biochemistry ,QP501-801 - Abstract
Objective Two experiments were conducted to determine the effects of adding exogenous phytase and xylanase, individually or in combination, as well as pelleting on nutrient digestibility, available energy content of wheat and the performance of growing pigs fed wheat-based diets. Methods In Experiment 1, forty-eight barrows with an initial body weight of 35.9±0.6 kg were randomly assigned to a 2×4 factorial experiment with the main effects being feed form (pellet vs meal) and enzyme supplementation (none, 10,000 U/kg phytase, 4,000 U/kg xylanase or 10,000 U/kg phytase plus 4,000 U/kg xylanase). The basal diet contained 97.8% wheat. Pigs were placed in metabolic cages for a 7-d adaptation period followed by a 5-d total collection of feces and urine. Nutrient digestibility and available energy content were determined. Experiment 2 was conducted to evaluate the effects of pelleting and enzymes on performance of wheat for growing pigs. In this experiment, 180 growing pigs (35.2±9.0 kg BW) were allocated to 1 of 6 treatments according to a 2×3 factorial treatment arrangement with the main effects being feed form (meal vs pellet) and enzyme supplementation (0, 2,500 or 5,000 U/kg xylanase). Results In Experiment 1, there were no interactions between feed form and enzyme supplementation. Pelleting reduced the digestibility of acid detergent fiber (ADF) by 6.4 percentage units (p
- Published
- 2017
- Full Text
- View/download PDF
47. Fatigue crack growth in turbine rotor steel: Oxidation at elevated temperature
- Author
-
Y.-Y. Yan
- Subjects
Crack closure ,Materials science ,Creep ,Applied Mathematics ,Mechanical Engineering ,Metallurgy ,General Materials Science ,Paris' law ,Condensed Matter Physics ,Turbine rotor ,Corrosion - Abstract
An analysis involving the kinetics and interactions of fatigue and corrosion is made. Accounted for in particular is the effect of oxidation on fatigue crack growth where data are obtained for the turbine rotor steel from 20°C to 550°C. Predictions on the fatigue life of structural components can be made in situations where the influence of creep is negligible. The analytical and test results agreed.
- Published
- 1989
- Full Text
- View/download PDF
48. Effects of Post-harvest Storage Duration and Variety on Nutrient Digestibility and Energy Content Wheat in Finishing Pigs
- Author
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P. P. Guo, P. L. Li, Z. C. Li, H. H. Stein, L. Liu, T. Xia, Y. Y. Yang, and Y. X. Ma
- Subjects
Digestibility ,Digestible and Metabolizable Energy ,Finishing Pigs ,Post-harvest Storage ,Wheat ,Animal culture ,SF1-1100 ,Animal biochemistry ,QP501-801 - Abstract
This study was conducted to investigate the effects of post-harvest storage duration and wheat variety on the digestibility and energy content of new season wheat fed to finishing pigs. Two wheat varieties (Shi and Zhong) were harvested in 2013 and stored in the warehouse of the Fengning Pig Experimental Base at China Agricultural University for 3, 6, 9, or 12 mo. For each storage period, 12 barrows were placed in metabolism crates and allotted to diets containing 1 of the 2 wheat varieties in a randomized complete block design. The experimental diets contained 97.34% wheat and 2.66% of a vitamin and trace mineral premix. With an extension of storage duration from 3 mo to 12 mo, the gross energy (GE) and crude protein (CP) of the wheat decreased by 2.0% and 12.01%, respectively, while the concentration of neutral detergent fiber (NDF), acid detergent fiber (ADF) and starch content increased by 30.26%, 19.08%, and 2.46%, respectively. Total non-starch polysaccharide, total arabinose, total xylose and total mannose contents decreased by 46.27%, 45.80%, 41.71%, and 75.66%, respectively. However, there were no significant differences in the chemical composition between the two wheat varieties with the exception of ADF which was approximately 13.37% lower in Shi. With an extension of storage duration from 3 mo to 12 mo, the digestible energy (DE), metabolizable energy (ME) content and the apparent total tract digestibility of GE, CP, dry matter, organic matter, ether extract, ADF and metabolizability of energy in wheat decreased linearly (p
- Published
- 2015
- Full Text
- View/download PDF
49. Tropospheric carbon monoxide over the Pacific during HIPPO: two-way coupled simulation of GEOS-Chem and its multiple nested models
- Author
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Y.-Y. Yan, J.-T. Lin, Y. Kuang, D. Yang, and L. Zhang
- Subjects
Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
Global chemical transport models (CTMs) are used extensively to study air pollution and transport at a global scale. These models are limited by coarse horizontal resolutions that do not allow for a detailed representation of small-scale nonlinear processes over the pollutant source regions. Here we couple the global GEOS-Chem CTM and its three high-resolution nested models to simulate the tropospheric carbon monoxide (CO) over the Pacific Ocean during five High-performance Instrumented Airborne Platform for Environmental Research (HIAPER) Pole-to-Pole Observations (HIPPO) campaigns between 2009 and 2011. We develop a two-way coupler, the PeKing University CouPLer (PKUCPL), allowing for the exchange and interaction of chemical constituents between the global model (at 2.5° long. × 2° lat.) and the three nested models (at 0.667° long. × 0.5° lat.) covering Asia, North America, and Europe. The coupler obtains nested model results to modify the global model simulation within the respective nested domains, and simultaneously acquires global model results to provide lateral boundary conditions (LBCs) for the nested models. Compared to the global model alone, the two-way coupled simulation results in enhanced CO concentrations in the nested domains. Sensitivity tests suggest the enhancement to be a result of improved representation of the spatial distributions of CO, nitrogen oxides, and non-methane volatile organic compounds, the meteorological dependence of natural emissions, and other resolution-dependent processes. The relatively long lifetime of CO allows for the enhancement to be accumulated and carried across the globe. We found that the two-way coupled simulation increased the global tropospheric mean CO concentrations in 2009 by 10.4%, with a greater enhancement at 13.3% in the Northern Hemisphere. Coincidently, the global tropospheric mean hydroxyl radical (OH) was reduced by 4.2%, resulting in a 4.2% enhancement in the methyl chloroform lifetime (MCF; via reaction with tropospheric OH). The resulting CO and OH contents and MCF lifetime are closer to observation-based estimates. Both the global and the two-way coupled models capture the general spatiotemporal patterns of HIPPO CO over the Pacific. The two-way coupled simulation is much closer to HIPPO CO, with a mean bias of 1.1 ppb (1.4%) below 9 km compared to the bias at −7.2 ppb (−9.2%) for the global model alone. The improvement is most apparent over the North Pacific. Our test simulations show that the global model alone could resemble the two-way coupled simulation (especially below 4 km) by increasing its global CO emissions by 15% for HIPPO-1 and HIPPO-3, by 25% for HIPPO-2 and HIPPO-4, and by 35% for HIPPO-5. This has important implications for using the global model alone to constrain CO emissions. Thus, the two-way coupled simulation is a significantly improved model tool for studying the global impacts of air pollutants from major anthropogenic source regions.
- Published
- 2014
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50. [Experts consensus on standard items of the cohort construction and quality control of temporomandibular joint diseases (2024)].
- Author
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Hu M, Yang C, Liu HH, Lu HX, Yao C, Xie QF, Chen YJ, Fu KY, Fang B, Zhu SS, Zhou Q, Chen ZY, Zhu YM, Zhang QB, Yan Y, Long X, Li ZY, Gan YH, Yu SB, Bai YX, Zhang Y, Wang YY, Lei J, Cheng Y, Liu CK, Cao Y, He DM, Wen N, Zhang SY, Chen MJ, Jiao GL, Liu XH, Jiang H, He Y, Shen P, Huang HT, Li YF, Zheng JS, Guo J, Zhao LS, and Xu LQ
- Subjects
- Humans, Cohort Studies, Consensus, Temporomandibular Joint Disorders therapy, Temporomandibular Joint Disorders diagnosis, Quality Control
- Abstract
Temporomandibular joint (TMJ) diseases are common clinical conditions. The number of patients with TMJ diseases is large, and the etiology, epidemiology, disease spectrum, and treatment of the disease remain controversial and unknown. To understand and master the current situation of the occurrence, development and prevention of TMJ diseases, as well as to identify the patterns in etiology, incidence, drug sensitivity, and prognosis is crucial for alleviating patients'suffering.This will facilitate in-depth medical research, effective disease prevention measures, and the formulation of corresponding health policies. Cohort construction and research has an irreplaceable role in precise disease prevention and significant improvement in diagnosis and treatment levels. Large-scale cohort studies are needed to explore the relationship between potential risk factors and outcomes of TMJ diseases, and to observe disease prognoses through long-term follw-ups. The consensus aims to establish a standard conceptual frame work for a cohort study on patients with TMJ disease while providing ideas for cohort data standards to this condition. TMJ disease cohort data consists of both common data standards applicable to all specific disease cohorts as well as disease-specific data standards. Common data were available for each specific disease cohort. By integrating different cohort research resources, standard problems or study variables can be unified. Long-term follow-up can be performed using consistent definitions and criteria across different projects for better core data collection. It is hoped that this consensus will be facilitate the development cohort studies of TMJ diseases.
- Published
- 2024
- Full Text
- View/download PDF
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