EXPERIMENTAL INVESTIGATION OF IMPACTS OF INJECTION TIMING AND PRESSURE ON COMBUSTION AND PARTICULATE MATTER EMISSION IN A SPRAY-GUIDED GDI ENGINE

Miaomiao Zhang,Wei Hong,Fangxi Xie,Yan Su,Liwei Han,Bin Wu 한국자동차공학회 2018 International journal of automotive technology Vol.19 No.3

A detailed investigation of the impact of injection timing and injection pressure on combustion and particles of a spray-guided GDI engine was conducted, under different engine operating conditions. The results indicated that, more proportion of large particles were emitted when increasing engine load, and the peak of accumulation mode particles moved toward smaller size when rising engine speed. With retarding the injection timing, the in-cylinder pressure and heat release rate rose first and then dropped at 2000 rpm, but they continuously rose at lower or higher speed conditions. The total particles concentration curves at all cases showed a trend of U-shape, and the corresponding timing of the lowest particles concentration advanced as the engine speed or load increased. The minimum value of emitted particles first rose and then fell when increasing load at 2000 rpm conditions, and it continuously rose when increasing speed at 40 Nm conditions. Generally, injection pressure did no sensitively affect combustion process except that it showed a relatively strong impact at low load conditions. However, particulate matter could be effectively inhibited by elevating fuel pressure from 5.5 to 11.5 MPa at all cases. In detail, the total particles concentration continuously fell at low speed and mid speed-high load cases, but it showed a rose trend when further increase fuel injection pressure at mid speed-low load and high-speed conditions.

Dynamic fracture instability in brittle materials: Insights from DEM simulations

Miaomiao Kou,Dongchen Han,Congcong Xiao,Yunteng Wang 국제구조공학회 2019 Structural Engineering and Mechanics, An Int'l Jou Vol.71 No.1

In this article, the dynamic fracture instability characteristics, including dynamic crack propagation and crack branching, in PMMA brittle solids under dynamic loading are investigated using the discrete element method (DEM) simulations. The microscopic parameters in DEM are first calibrated using the comparison with the previous experimental results not only in the field of qualitative analysis, but also in the field of quantitative analysis. The calibrating process illustrates that the selected microscopic parameters in DEM are suitable to effectively and accurately simulate dynamic fracture process in PMMA brittle solids subjected to dynamic loads. The typical dynamic fracture behaviors of solids under dynamic loading are then reproduced by DEM. Compared with the previous experimental and numerical results, the present numerical results are in good agreement with the existing ones not only in the field of qualitative analysis, but also in the field of quantitative analysis. Furthermore, effects of dynamic loading magnitude, offset distance of the initial crack and initial crack length on dynamic fracture behaviors are numerically discussed.

Calixarene-based chemosensors by means of click chemistry.

Song, Miaomiao,Sun, Zhongyue,Han, Cuiping,Tian, Demei,Li, Haibing,Kim, Jong Seung Wiley-VCH 2014 Chemistry - An Asian Journal Vol.9 No.9

<P>Click chemistry, a new strategy for organic chemistry, has been widely used in the chemical modification of calixarenes because of its reliability, specificity, biocompatibility, and efficiency. Click-derived triazoles also play a critical role in sensing ions and molecules. This in-depth review provides an overview of calixarene-based chemosensors that incorporate click-derived triazoles, and their three characteristics (chromogenic, fluorescence, and wettability) are reviewed.</P>

Genome-wide identification of the valine-glutamine motif containing gene family and the role of VQ25-1 in pollen germination in Brassica oleracea

Yang Miaomiao,Liu Ziwei,Yu Yuanhui,Yang Min,Guo Li,Han Xuejie,Ma Xiangjie,Huang Ziya,Gao Qiguo 한국유전학회 2023 Genes & Genomics Vol.45 No.7

Background The plant-specific valine-glutamine (VQ) motif containing proteins tightly regulate plant growth, development, and stress responses. However, the genome-wide identification and functional analysis of Brassica oleracea (B. oleracea) VQ genes have not been reported. Objective To identify the VQ gene family in B. oleracea and analyze the function of Bo25-1 in pollen germination. Methods The Hidden Markov Model (HMM) of VQ family was used to query the BoVQ genes in the B. oleracea genome. The BoVQ genes preferentially expressed in anthers were screened by qRT-PCR. Subcellular localization of VQ25-1 was observed in Nicotiana benthamiana (N. benthamiana) leaves. To analysis the role of BoVQ25-1 in pollen germination, the expression of BoVQ25-1 was suppressed using antisense-oligonucleotides (AS-ODN). Results A total of 64 BoVQ genes were identified in the B. oleracea genome. BoVQ25-1 was found to be preferentially expressed in the B. oleracea anthers. BoVQ25-1 was cloned from the anthers of the B. oleracea cultivar ‘Fast Cycle’. BoVQ25-1 is localized to the nucleus. The pollen germination rate significantly decreased after AS-ODN treatment. Conclusion Sixty-four BoVQ genes were identified in the B. oleracea genome, of which BoVQ25-1 plays an important role in pollen germination.

Differential Hrd1 Expression and B-Cell Accumulation in Eosinophilic and Non-eosinophilic Chronic Rhinosinusitis With Nasal Polyps

Kun Chen,Miaomiao Han,Mengyao Tang,Yadong Xie,Yuting Lai,Xianting Hu,Jia Zhang,Jun Yang,Huabin Li 대한천식알레르기학회 2018 Allergy, Asthma & Immunology Research Vol.10 No.6

Purpose: Hrd1 has recently emerged as a critical regulator of B-cells in autoimmune diseases. However, its role in the pathogenesis of chronic rhinosinusitis with nasal polyps (CRSwNP) remains largely unexplored. This study aimed to examine Hrd1 expression and B-cell accumulation and their possible roles in CRSwNP. Methods: Quantitative real-time polymerase chain reaction, immunohistochemistry, enzyme-linked immunosorbent assay and Western blotting were used to assess gene and protein expression in nasal tissue extracts. Cells isolated from nasal tissues and peripheral blood mononuclear cells were characterized by flow cytometry. Local antibody production was measured in tissue extracts with a Bio-Plex assay. Additionally, changes in Hrd1 expression in response to specific inflammatory stimuli were measured in cultured dispersed polyp cells. Results: Nasal polyps (NPs) from patients with eosinophilic CRSwNP (ECRS) had increased levels of Hrd1, B-cells and plasma cells compared with NPs from patients with non-eosinophilic CRSwNP (non-ECRS) or other control subjects (P < 0.05). The average Hrd1 levels in B-cells in NPs from ECRS patients were significantly higher than those from non-ECRS patients and control subjects (P < 0.05). NPs also contained significantly increased levels of several antibody isotypes compared with normal controls (P < 0.05). Interestingly, Hrd1 expression in cultured polyp cells from ECRS patients, but not non-ECRS patients, was significantly increased by interleukin-1β, lipopolysaccharide and Poly(I:C) stimulation, and inhibited by dexamethasone treatment (P < 0.05). Conclusions: Differential Hrd1 expression and B-cell accumulation between the ECRS and non-ECRS subsets suggests that they can exhibit distinct pathogenic mechanisms and play important roles in NP.

Protective effect of quercetin against myocardial ischemia as a Ca2+ channel inhibitor: involvement of inhibiting contractility and Ca2+ infl ux via L-type Ca2+ channels

Yingran Liang,Yuanyuan Zhang,Miaomiao Liu,Xue Han,Jianping Zhang,Xuan Zhang,Li Chu 대한약학회 2020 Archives of Pharmacal Research Vol.43 No.8

Many studies describe the stimulating eff ect ofquercetin on Ca 2+ channels and the treatment of cardiovasculardiseases such as myocardial ischemia and hypertension. However, these studies are scattered and contradictory. The aim of this study is to elucidate the protective eff ects ofquercetin against isoproterenol (ISO)-induced myocardialischemia and verify the cellular mechanisms based on theL-type Ca 2+ channel (LTCC), Ca 2+ transients, and myocardialcontractility. An animal model of myocardial ischemiawas established by subcutaneous injection of ISO for 2 days. Quercetin significantly reduced J-point elevation, heartrate, reactive oxygen species, serum levels of myocardialenzymes, superoxide dismutase, catalase, glutathione, glutathioneperoxidase, glutathione S-transferase and improvedheart pathologic morphology. L-type Ca 2+ current (I Ca-L )was tested in an experiment with isolated rat myocardialcells by using the whole-cell patch-clamp recording techniqueand IonOptix Myocam detection system. Quercetin reduced I Ca-L in a concentration-dependent fashion with ahalf-maximal inhibitory concentration of 4.67 × 10 –4 M. Quercetin also shifted the current–voltage curve upwards,moved the activation and inactivation curves to the left andinhibited the amplitude of the cell shortening and Ca 2+ transients. The results showed that quercetin acts as a LTCCinhibitor and exerts a cardioprotective eff ect by inhibitingCa 2+ infl ux and contractility in rats.

Distinct Inflammatory Profiles in Atopic and Nonatopic Patients With Chronic Rhinosinustis Accompanied by Nasal Polyps in Western China

Luo Ba,Jintao Du,Feng Liu,Sixi Liu,Fenglin Yang,Miaomiao Han,Ping Lin,Huabin Li 대한천식알레르기학회 2015 Allergy, Asthma & Immunology Research Vol.7 No.4

Purpose: The role of systemic sensitization in the pathophysiology of chronic rhinosinusitis with nasal polyps (CRSwNP) remains elusive. This study sought to characterize the pattern of cytokines in polyp tissues from atopic and nonatopic patients with CRSwNP. Methods: Atopic and nonatopic polyp and normal tissues were collected from 70 CRSwNP patients and 26 control subjects, respectively. The distribution of inflammatory cells (eosinophils, neutrophils, mast cells, etc.) were examined using immunohistochemistry, the mRNA levels of the transcription factors GATA-3, T-bet, RORc, and FOXP3 were determined using quantitative real-time polymerase chain reaction. The levels of inflammatory mediators (IFN-γ, IL-5, IL- 17A, etc.) in tissue homogenates were measured using enzyme-linked immunosorbent assay (ELISA). Moreover, the levels of inflammatory mediators in the supernatant of anti-IgE stimulated polyp tissues were measured using ELISA. Results: Atopic CRSwNP patients were characterized by increased eosinophil accumulation, enhanced eosinophilic inflammation (elevated IL-5, ECP, and total IgE), and significantly increased GATA-3 mRNA levels (P<0.05), whereas both atopic and non-atopic CRSwNP patients showed decreased FOXP3 mRNA expression (P<0.05). After addition of anti- IgE stimulation, atopic CRSwNP patients produced more IL-5, IL-2, IL-10, IL-17A, and PGD2 in the supernatant of stimulated polyp tissues than nonatopic CRSwNP patients did. Conclusions: Atopic and nonatopic CRSwNP patients may possess the patterns of inflammatory response in polyp tissues.

Analysis of Peripheral B Cell Subsets in Patients With Allergic Rhinitis

Jing Luo,Huanhuan Guo,Zhuofu Liu,Tao Peng,Xianting Hu,Miaomiao Han,Xiangping Yang,Xuhong Zhou,Huabin Li 대한천식알레르기학회 2018 Allergy, Asthma & Immunology Research Vol.10 No.3

Purpose: Recent evidence suggests that B cells can both promote and inhibit the development and progression of allergic disease. However, the characteristics of B cell subsets in patients with allergic rhinitis (AR) have not been well documented. This study aimed to analyze the characteristics of B cell subsets in the peripheral blood of AR patients. Methods: Forty-seven AR patients and 54 healthy controls were enrolled in this study, and the B cell subsets in peripheral blood of all subjects were analyzed by flow cytometry. Moreover, the serum total immunoglobulin E (IgE) and IgE concentrations secreted into the cultured peripheral blood mononuclear cells (PBMCs) were measured by using enzyme-linked immunosorbent assay. Results: We found the peripheral blood of AR patients contained higher percentages of memory B cells, plasma cells, and CD19+CD24hiCD27+ regulatory B cells (Bregs) than those of age-matched healthy controls (P<0.05), while the percentages of naïve B cells and CD19+CD24hiCD38hi Bregs were significantly lower in AR patients than in healthy individuals (P<0.05). In addition, the serum total IgE and IgE concentrations secreted into the cultured PBMCs were elevated in AR patients than in the healthy controls (P<0.05). Conclusions: Our findings indicate that AR patients were characterized by increase in terminally differentiated memory B cells or plasma cells and decreases in CD19+CD24hiCD38hi Breg cells in the peripheral blood.