28 results on '"Lihong Guo"'
Search Results
2. A Low-Brightness Image Enhancement Algorithm Based on Multi-Scale Fusion
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Enqi Zhang, Lihong Guo, Junda Guo, Shufeng Yan, Xiangyang Li, and Lingsheng Kong
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brightness enhancement ,image fusion ,image processing ,Laplacian pyramid ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
Images captured in low-brightness environments typically have low brightness, low contrast, and high noise levels, which significantly affect the overall image quality. To improve the image quality, a low-brightness image enhancement algorithm based on multi-scale fusion is proposed. First, a novel brightness transformation function is used for the generation of two images with different brightnesses. Then, the illumination estimation technique is used to construct a weight matrix, which facilitates the extraction of advantageous features from each image. Finally, the enhanced image is obtained by the fusion of two images using the weight matrix and the pyramid reconstruction algorithm. The proposed method has a better enhancement effect as shown by the experimental results. Compared to other image enhancement algorithms, it has lower evaluation values in the natural image quality evaluator (NIQE) and lightness order error (LOE) indices. The lowest average NIQE value of the proposed algorithm in each dataset is 2.836. This further demonstrates its superior performance.
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- 2023
- Full Text
- View/download PDF
3. Theory of AdaDelSPGD Algorithm in Fiber Laser-Phased Array Multiplex Communication Systems
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Jiayu Chen, Jinsheng Liu, Long Han, Mingru Ci, Dongbo Che, Lihong Guo, and Hongjun Yu
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SPGD algorithm ,laser communication ,phase lock ,laser coherent synthesis ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
Stochastic parallel gradient descent (SPGD) algorithm is one of the most promising methods for effective coherent beam combination. However, the algorithm also has some disadvantages, such as slow convergence speed and local extremum. This paper proposes an AdaDelSPGD algorithm, which combines an AdaDelta algorithm with a SPGD algorithm, and improves the traditional AdaDelta algorithm with adaptive gain coefficient. It is worth noting that the adaptive gain coefficient can be adjusted in real time to improve the convergence rate. The effectiveness of the proposed algorithm is verified by relevant simulation experiments, and the results show that the proposed algorithm can significantly improve the convergence speed. Following the experiments with the fiber laser-phased array multiplex communication system, we can draw the conclusion that the addition of communication modulation reduces the beam quality, and the higher the modulation frequency, the worse the beam quality. However, adding the SPGD algorithm can improve the beam quality. The AdaDelSPGD algorithm proposed in this paper can further improve the beam quality, and the bit error rate of communication is also decreased after testing. This provides a foundation for further research on the fiber laser-phased array multiplex communication system.
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- 2022
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4. A Tunable Mid-Infrared Solid-State Laser with a Compact Thermal Control System
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Deyang Yu, Yang He, Kuo Zhang, Qikun Pan, Fei Chen, and Lihong Guo
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tunable mid-infrared solid-state laser ,thermal control ,all-fiber laser ,thermoelectric cooling ,finite-element analysis ,optical parametric oscillator ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
Tunable mid-infrared lasers are widely used in laser spectroscopy, gas sensing and many other related areas. In order to solve heat dissipation problems and improve the environmental temperature adaptability of solid-state laser sources, a tunable all-fiber laser pumped optical parametric oscillator (OPO) was established, and a compact thermal control system based on thermoelectric coolers, an automatic temperature control circuit, cooling fins, fans and heat pipes was integrated and designed for the laser. This system is compact, light and air-cooling which satisfies the demand for miniaturization of lasers. A mathematical model and method was established to estimate the cooling capacity of this thermal control system under different ambient environments. A finite-element model was built and simulated to analyze the thermal transfer process. Experiments in room and high temperature environments were carried out and showed that the substrate temperature of a pump module could be maintained at a stable value with controlled precision to 0.2 degrees, while the output power stability of the laser was within ±1%. The experimental results indicate that this compact air-cooling thermal control system could effectively solve the heat dissipation problem of mid-infrared solid-state lasers with a one hundred watts level pump module in room and high temperature environments.
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- 2018
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5. Green synthesis of copper nanoparticles using Cinnamomum zelanicum extract and its applications as a highly efficient antioxidant and anti-human lung carcinoma
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Guan Wang, Kejun Nan, Jinpeng Liu, Yang Liu, Lihong Guo, Haocong Liu, and Jie Zhang
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Antioxidant ,Materials science ,Traditional medicine ,biology ,medicine.medical_treatment ,Chemical technology ,Biomedical Engineering ,copper nanoparticles ,Nanoparticle ,chemistry.chemical_element ,human lung carcinoma ,Bioengineering ,TP1-1185 ,biology.organism_classification ,Copper ,cinnamomum zelanicum leaf ,Human lung ,medicine.anatomical_structure ,chemistry ,medicine ,TA401-492 ,General Materials Science ,Medicinal plants ,Materials of engineering and construction. Mechanics of materials ,Cinnamomum - Abstract
Cinnamomum zelanicum is one of the popular medicinal plants. The plant has many pharmaceutical uses in traditional medicine. In this study, copper nanoparticles were synthesized using the aqueous extract of Cinnamomum zelanicum. The CuNPs were characterized using different techniques such as EDX, FE-SEM, XRD, and FT-IR. The FE-SEM results confirm spherical morphology for the nanoparticles with size of 19.55 to 69.70 nm. For investigating the antioxidant property of CuNPs, the DPPH test was used in the presence of butylated hydroxytoluene as the positive control. To survey the cytotoxicity and anti-human lung carcinoma effects of CuNPs, MTT assay was used on the NCI-H2126, NCI-H1437, NCI-H1573, and NCI-H661 cell lines. DPPH test revealed similar antioxidant potentials for Cinnamomum zelanicum aqueous extract, CuNPs, and butylated hydroxytoluene. Copper nanoparticles had very low cell viability and anti-lung carcinoma properties dose-dependently against NCI-H2126, NCI-H1437, NCI-H1573, and NCI-H66 cell lines without any cytotoxicity on the normal cell line. The best result of anti-lung carcinoma properties of CuNPs against the above cell lines was seen in the case of the NCI-H2126 cell line. According to the above findings, the copper nanoparticles containing Cinnamomum zelanicum can be administrated in humans for the treatment of several types of lung carcinoma.
- Published
- 2021
6. Two-Photon-Induced Charge-Variable Conjugated Polyelectrolyte Brushes for Effective Gene Silencing
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Lihong Guo, Junzi Li, Wenbo Hu, Xiaofei Miao, Haojie Tao, Hui Zhao, Xiaomei Lu, Wei Huang, Quli Fan, Qi Wang, Tingchao He, and Yufu Tang
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Small interfering RNA ,Chemistry ,media_common.quotation_subject ,Biochemistry (medical) ,Biomedical Engineering ,Cationic polymerization ,General Chemistry ,Transfection ,Conjugated Polyelectrolytes ,Biomaterials ,Förster resonance energy transfer ,Biophysics ,Side chain ,Gene silencing ,Internalization ,media_common - Abstract
Cationic conjugated polyelectrolytes can absorb negatively charged small interfering RNA (siRNA) and also visualize the cellular internalization of siRNA, which thus have been extensively explored as siRNA carriers. However, their low charge density cannot afford a high carrying capability, severely impeding gene transfection efficiency. Moreover, the intracellular controlled release of siRNA is another factor that limits the widespread use of siRNA therapeutics. Herein, we present a novel two-photon-induced charge-variable conjugated polyelectrolyte brush as an efficient siRNA carrier. This cationic conjugated polyelectrolyte brush (PPENBr-ONB) with densely cationic charges produces remarkable carrying capability with siRNA. In addition, PPENBr-ONB with large two-photon absorption (TPA) cross-section represents effective fluorescence resonance energy transfer (FRET) to photoresponsive side chain with 720 nm illumination for two-photon-induced photolysis. Hence, the charge transformation of the photoresponsive side chain from cations to zwitterions would remarkably elevate siRNA release. The obtained PPENBr-ONB shows considerable fluorescence quantum yields (0.16) in aqueous solution, sufficient to serve as a reporter for cellular imaging. Agarose gel electrophoresis experiments indicate that PPENBr-ONB exhibit excellent siRNA-loading capacity (1 mol PPENBr-ONB to more than 20 mol siRNA). Furthermore, PPENBr-ONB with large TPA cross-section (1.47 × 10
- Published
- 2022
7. Solution Synthesis of Layered van der Waals (vdW) Ferromagnetic CrGeTe3 Nanosheets from a Non-vdW Cr2Te3Template
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Fang Wang, Huan Yang, Liyan Hu, Lanfang Wang, Lihong Guo, Huisheng Zhang, Ding-Jiang Xue, and Xiaohong Xu
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Steric effects ,Chemistry ,General Chemistry ,Solution synthesis ,010402 general chemistry ,01 natural sciences ,Biochemistry ,Catalysis ,Lower energy ,0104 chemical sciences ,symbols.namesake ,Colloid and Surface Chemistry ,Ferromagnetism ,Chemical physics ,Lattice (order) ,symbols ,Curie temperature ,van der Waals force ,Ferromagnetic order - Abstract
CrGeTe3 has recently emerged as a new class of two-dimensional (2D) materials due to its intrinsic long-range ferromagnetic order. However, almost all the reported synthesis methods for CrGeTe3 nanosheets are based on the conventional mechanical exfoliation from single-crystalline CrGeTe3, which is prepared by the complicated self-flux technique. Here we report a solution-processed synthesis of CrGeTe3 nanosheets from a non-van der Waals (vdW) Cr2Te3 template. This structure evolution from non-vdW to vdW is originated from the substitution of Ge atoms on the Cr sites surrounded by fewer Te atoms in the Cr2Te3 lattice due to their smaller steric hindrance and lower energy barrier. These CrGeTe3 nanosheets present regular hexagonal structures with a diameter larger than 1 μm and excellent stability. They exhibit soft magnetic behavior with a Curie temperature lower than 67.5 K. This non-vdW to vdW synthesis strategy promotes the development of CrGeTe3 in ferromagnetism while providing an effective route to synthesize other 2D materials.
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- 2020
8. Promoting dimethyl ether carbonylation over hot-water pretreated H-mordenite
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Shuaishuai Lyu, Ye Tian, Lihong Guo, Na Zhao, Qingpeng Cheng, Xinbin Ma, Xingang Li, Tong Ding, and Jun Xu
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02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Catalysis ,Mordenite ,0104 chemical sciences ,chemistry.chemical_compound ,chemistry ,Proton NMR ,Dimethyl ether ,Methanol ,0210 nano-technology ,Zeolite ,Brønsted–Lowry acid–base theory ,Carbonylation ,Nuclear chemistry - Abstract
Herein, we report the effect of the hot-water pretreatment on the catalytic activity of the H-mordenite (H-MOR) zeolite for DME carbonylation. The structure and acidity of the H-MOR catalysts pretreated by hot water were systematically characterized by XRD, nitrogen adsorption, SEM, H2O-TPD, NH3-TPD, 1H NMR and NH3-DRIFTS technologies. With the increase of the duration of the hot-water pretreatment, the catalytic activity shows a volcano-type variation. The H-MOR catalyst pretreated by hot water for 10 min at 573 K displays the highest catalytic activity among all of the catalysts. The appropriate duration of the hot-water pretreatment can generate new medium strong and strong Bronsted acid sites, which changes the microenvironment in the pores of H-MOR. Additionally, the newly generated Bronsted acid sites will accelerate the first step of DME carbonylation, that is, DME reacts with the Bronsted acid sites of the zeolite forming surface methoxy groups and methanol, improving the catalytic activity of the catalysts. However, too long duration of the hot-water pretreatment will remain water molecules in H-MOR, which inhibits DME carbonylation.
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- 2020
9. Apocynin protects retina cells from ultraviolet radiation damage via inducing sirtuin 1
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Jinsheng Hong, Chen Lin, Chuanshu Cai, Feng Liu, Weijian Zhang, Lihong Guo, and Jianrong Zhang
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Male ,Retinal Ganglion Cells ,inorganic chemicals ,Programmed cell death ,Ultraviolet Rays ,Pharmaceutical Science ,Retinal Pigment Epithelium ,02 engineering and technology ,medicine.disease_cause ,Retinal ganglion ,Cell Line ,Mice ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Sirtuin 1 ,medicine ,Animals ,Humans ,cardiovascular diseases ,Mice, Inbred BALB C ,Retina ,Retinal pigment epithelium ,biology ,Acetophenones ,Retinal ,021001 nanoscience & nanotechnology ,Cell biology ,Oxidative Stress ,medicine.anatomical_structure ,chemistry ,Gene Knockdown Techniques ,030220 oncology & carcinogenesis ,Apocynin ,cardiovascular system ,biology.protein ,sense organs ,0210 nano-technology ,Oxidative stress ,circulatory and respiratory physiology - Abstract
Direct exposure to Ultraviolet (UV) radiation causes progressive damages in retinal cells, which is one of the hypothetical mechanisms underlying age-related retinopathy or macular degeneration. The protective effects of Apocynin against UV damages were firstly tested in retinal pigment epithelium cells (RPEs) and retinal ganglion cells (RGCs). Subsequently the beneficial effect of Apocynin on mouse retinas against light damage were examined. Next, microarray profiling was used to identify the genes regulated by Apocynin in both RPEs and RGCs. A candidate gene was isolated for functional characterisation by knock-down study. Apocynin was shown to inhibit cell death, reduce oxidative stress and deoxyribonucleic acid damages in both RPEs and RGCs challenged with UV. Intravitreal application of Apocynin also improved retinal dysfunction caused by light damage. Sirtuin 1 (SIRT1) was identified as induced by Apocynin by microarray study. The induction was confirmed by realtime-PCR and western blotting. Knocking down SIRT1 antagonised the protective effect of Apocynin against UV damages in both RPEs and RGCs. Apocynin is a novel agent that shows both in vitro and in vivo efficacies against UV radiation induced retina damages. SIRT1 pathway is implicated in UV radiation protection of Apocynin in retinal cells.
- Published
- 2019
10. Fabrication of Heterogeneous H6PV3MoW8O40/AC-Ag Catalyst for Biodiesel Production from Low-Quality Oils
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Wenlei Xie, Chunli Gao, and Lihong Guo
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food.ingredient ,Metal ions in aqueous solution ,Transesterification ,Soybean oil ,Catalysis ,chemistry.chemical_compound ,food ,chemistry ,Chemical engineering ,Biodiesel production ,medicine ,Methanol ,Dispersion (chemistry) ,Activated carbon ,medicine.drug - Abstract
Herein, we first modified commercial activated carbon (AC) with different metal ions (Cs+, K+ and Ag+), and then H6PV3MoW8O40 acids were incorporated into as-modified supports。The 35%H6PV3MoW8O40/AC-Ag hybrid catalyst showed highly catalytic performance for transesterification of soybean oil. The best oil conversion of 91.3% was achieved under optimized conditions: methanol/oil ratio of 30:1, reaction time of 10 h, reaction temperature of 140 °C and catalyst dosage of 8 wt.%. Characterization results of XRD, IR, ICP and TG indicated that H6PV3MoW8O40 was highly dispersed on the AC-Ag support as the loading was less than 35%. Proton exchange with Ag may contribute to the highly dispersion of H6PV3MoW8O40 on the support, thereof leading to the increased stability. The as-prepared 35%H6PV3MoW8O40/AC-Ag catalyst was recycled and had good resistance to free fatty acid (FFA) and water, which were included in low-quality oils. Moreover, the solid acid catalyst could simultaneously catalyze the transesterification of soybean oil and esterification of FFA, and a probable mechanism of the catalytic process was also proposed. All the features of this novel solid catalyst are more advantageous than homogenous H6PV3MoW8O40 catalyst, successfully creating an efficient and sustainable approach of biodiesel production especially from low-quality oils.
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- 2021
11. Proteomic and metabolic characterization of membrane vesicles derived from Streptococcus mutans at different pH values
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Dongru Chen, Yina Cao, Yan Zhou, Ruixue Wu, Lihong Guo, and Huancai Lin
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Proteomics ,Virulence ,ATP-binding cassette transporter ,Dental Caries ,Applied Microbiology and Biotechnology ,Streptococcus mutans ,03 medical and health sciences ,Metabolomics ,Bacterial Proteins ,Humans ,030304 developmental biology ,0303 health sciences ,biology ,030306 microbiology ,Chemistry ,Biofilm ,General Medicine ,Hydrogen-Ion Concentration ,biology.organism_classification ,Biochemistry ,Biofilms ,Intracellular ,Function (biology) ,Biotechnology - Abstract
Bacterial membrane vesicles (MVs) are used as a tool for intercellular communication and seem essential for bacterial survival. However, few data are available on MVs generated by Streptococcus mutans, which is the main aetiological agent of dental caries. The present study presents an integrated proteomics and metabolomics analysis of MVs isolated from S. mutans at initial pH values of 7.5 and 5.5 and explores their function. The results showed that S. mutans releases more MVs with smaller diameters under acidic conditions than under neutral conditions. Proteomic analysis showed 344 common vesicular proteins, including various virulence factors. The expressions of 140 individual proteins and 37 metabolites were altered as a result of culturing S. mutans at different pH values. Co-analyses of proteomic and metabolomics data indicated that ABC transporters underwent significant changes under acid pressure. We concluded that S. mutans produced MVs at different pH values to carry proteins associated with cariogenesis. Moreover, the alterations of S. mutans MVs under acid pressure were associated with ABC transporters. These results increase our knowledge of S. mutans MVs and imply that S. mutans MVs may play a functional role in carious infection. KEY POINTS: • S. mutans MVs contained virulence factor-related proteins, even at low pH values. • Integrated proteomics and metabolomics analysis showed that S. mutans MVs alterations under acidic conditions were associated with ABC transporters.
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- 2019
12. Sr doping effect on the structure property and NO oxidation performance of dual-site doped perovskite La(Sr)Co(Fe)O3
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Ling Bo, Lihong Guo, Xingang Li, Ying Li, Zheng Jiang, and Ye Tian
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Materials science ,Spin states ,Doping ,chemistry.chemical_element ,02 engineering and technology ,General Chemistry ,Activation energy ,Crystal structure ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Oxygen ,0104 chemical sciences ,Catalysis ,Adsorption ,chemistry ,Physical chemistry ,General Materials Science ,0210 nano-technology ,Perovskite (structure) - Abstract
In this work, the physico-chemical properties of the La1-xSrxCo0.8Fe0.2O3 (x = 0, 0.3,0.4,0.5,0.6) catalysts were systematically studied as well as their catalytic activity for NO oxidation. When Sr2+ substituted at La3+ site, [CoO6] octahedral distortion is amended and the crystal structure transited from rhombohedral to cubic. Co(III) electronic configuration turned from high/intermediate spin state to low spin sate with empty eg filling. Imbalanced positive charge induced by Sr2+ was compensated by tetravalent Co(IV) ions and oxygen deficiencies together. All these factors resulted in better reducibility of Co, increasing oxygen deficiencies and more mobile oxygen species. Thus, NO conversion of 67–69% was attained over the Sr-doped catalysts at 300 °C, much higher than the undoped catalysts (NO conversion of 24.3%). A significant decrease of the apparent activation energy (Ea), from 68 kJ/mol down to ~52 kJ/mol, was observed as well. Based on the kinetics results, NO oxidation over the perovskite catalysts is a typical superficial process determined by adsorbed NO and surface oxygen species.
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- 2021
13. The Antimicrobial Activity of Pomegranate Polyphenol Extract (POMx) Lozenges in a Saliva-Derived Biofilm Model System
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Wenyuan Shi, Lina Li, Renate Lux, Lihong Guo, and Lawrence E. Wolinsky
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Saliva ,Polyphenol ,Chemistry ,Biofilm ,Model system ,Food science ,Antimicrobial ,Lozenge - Published
- 2015
14. Maximizing Aggregation of Organic Fluorophores to Prolong Fluorescence Lifetime for Two-Photon Fluorescence Lifetime Imaging
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Qi Wang, Xiaofei Miao, Yun Ni, Wenbo Hu, Meng Xie, Hui Zhao, Xiaomei Lu, Lin Li, Wei Huang, Lihong Guo, Quli Fan, and Bai Lei
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Fluorescence-lifetime imaging microscopy ,Photons ,Materials science ,Fluorophore ,Polymers ,Optical Imaging ,Biomedical Engineering ,Pharmaceutical Science ,Nanoparticle ,Contrast Media ,Nanotechnology ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Two photon fluorescence ,Thioxanthone ,01 natural sciences ,Fluorescence ,0104 chemical sciences ,Biomaterials ,chemistry.chemical_compound ,chemistry ,Molecular imaging ,0210 nano-technology ,Absorption (electromagnetic radiation) - Abstract
Two-photon fluorescence lifetime imaging (TP-FLIM) not only permits imaging deep inside the tissues with precise spatial manipulation but also circumvents tissue autofluorescence, holding tremendous promise in molecular imaging. However, the serious lack of suitable contrast agents with long fluorescence lifetime and efficient two-photon absorption (TPA) greatly limits the advance of TP-FLIM. This study reports a simple approach to fabricate water-soluble organic semiconducting nanoparticles [thioxanthone (TXO) NPs] with ultralong fluorescence lifetime and efficient TPA for in vivo TP-FLIM. The approach utilizes the aggregation of a specifically selected thermally activated delayed fluorescence (TADF) fluorophore to prolong its fluorescence lifetime. Encapsulating the TADF fluorophore within an amphiphilic copolymer not only maximizes its aggregation but also obtains TXO NPs with efficient TPA. Importantly, as-prepared TXO NPs exhibit a considerably long fluorescence lifetime at a magnitude of 4.2 µs, which is almost 1000 times larger than that of existing organic contrast agents. Moreover, such long fluorescence lifetime is almost oxygen-inert, readily realizing both in vitro and in vivo TP-FLIM. This work may set valuable guidance for designing organic semiconducting materials with ultralong fluorescence lifetimes to fulfill the potential of FLIM.
- Published
- 2018
15. Paeonol Inhibits the Proliferation, Invasion, and Inflammatory Reaction Induced by TNF-α in Vascular Smooth Muscle Cells
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Liang Meng, Weidong Xu, Xiandong Zeng, Lihong Guo, and Wenqi Ning
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Male ,Vascular smooth muscle ,Interleukin-1beta ,Biophysics ,Apoptosis ,Caspase 3 ,Inflammation ,Biochemistry ,Muscle, Smooth, Vascular ,Rats, Sprague-Dawley ,chemistry.chemical_compound ,Bcl-2-associated X protein ,Western blot ,Cell Movement ,Proliferating Cell Nuclear Antigen ,medicine ,Animals ,Cells, Cultured ,Cell Proliferation ,bcl-2-Associated X Protein ,medicine.diagnostic_test ,biology ,Interleukin-6 ,Tumor Necrosis Factor-alpha ,Acetophenones ,Cell Biology ,General Medicine ,musculoskeletal system ,Molecular biology ,Caspase 9 ,Rats ,Matrix Metalloproteinase 9 ,Proto-Oncogene Proteins c-bcl-2 ,chemistry ,Immunology ,cardiovascular system ,biology.protein ,Matrix Metalloproteinase 2 ,Tumor necrosis factor alpha ,Paeonol ,medicine.symptom - Abstract
The aim of this study was to evaluate the effect of paeonol on the proliferation, migration, and inflammation induced by tumor necrosis factor (TNF-α) of rat vascular smooth muscle cells (VSMCs). Primary rat VSMCs were identified by immunofluorescence assay. The inhibition of VSMCs proliferation induced by TNF-α was observed after paeonol treatment in a dose-dependent manner. Treatment with 100 μM paeonol significantly reduced the expression of proliferating cell nuclear antigen (PCNA). On the other hand, transwell assay showed that treatment with paeonol suppressed the invasion of TNF-α-induced VSMCs and the production of inflammation factors stimulated by TNF-α. For apoptosis induced by paeonol, Western blot analysis showed that cleaved caspase-3 and -9 were detected, and pro-apoptotic protein Bax was up-regulated, whereas anti-apoptotic protein Bcl-2 was down-regulated by paeonol in TNF-α-stimulated VSMCs. ELISA analysis data showed that both levels of IL-1β and IL-6 produced by the stimulation of TNF-α were decreased by paeonol in a dose-dependent manner in VSMCs. These results suggest that paeonol can effectively inhibit the proliferation through apoptotic induction through caspase pathway in VSMCs induced by TNF-α. Also, paeonol significantly reduced the invasion and the inflammation stimulated by TNF-α in VSMCs.
- Published
- 2015
16. Developmental validation of a 6-dye typing system with 27 loci and application in Han population of China
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Meisen Shi, Zheng Li, Shuhua Ma, Lihong Guo, Rufeng Bai, Haiying Jin, and Yaju Liu
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Genetic Markers ,Male ,Combined DNA Index System ,China ,Science ,Buccal swab ,Biology ,01 natural sciences ,Article ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Asian People ,Gene Frequency ,Chromosomes, Human ,Humans ,030216 legal & forensic medicine ,Typing ,Allele frequency ,Genetics ,Multidisciplinary ,Amelogenin ,010401 analytical chemistry ,0104 chemical sciences ,Genetics, Population ,chemistry ,DNA profiling ,Genetic marker ,Medicine ,Female ,DNA ,Microsatellite Repeats - Abstract
In this study, a novel 27-locus system (now known as the SureID PanGlobal system), including 24 autosomal STRs (D3S1358, TH01, D21S11, D18S51, Penta E, D12S391, D6S1043, D2S1338, D1S1656, D2S441, D5S818, D13S317, D7S820, D19S433, CSF1PO, Penta D, vWA, D8S1179, TPOX, FGA, D16S539, D22S1045, SE33, D10S1248), two Y-chromosome markers (DYS391 and Y-indel) and the sex determining marker, Amelogenin was developed with six fluorescent dyes labeling. The included STR loci belonged to the core loci in the Combined DNA Index System (CODIS) and the European Standard Set (ESS) as well as some additional loci commonly used in commercial kits and national DNA databases. This paper describes the validation studies conducted with the SureID PanGlobal system using Applied Biosystems 3500 XL Genetic Analyzer for fragment length detection that included the analysis of the following parameters and aspects: PCR conditions, sensitivity, species specificity, inhibition, precision, stutter, DNA mixtures, and stability studies with crime scene samples. The studies demonstrated that the SureID PanGlobal system is reproducible, accurate, sensitive and robust for forensic application and databasing. Additionally, the whole cycling time of the system can finish within 65 minutes, which was developed specifically for rapid and reliable generation of DNA profiles obtained from blood, buccal swabs and forensic stains.
- Published
- 2017
17. Arabidopsis heat shock factor HsfA1a directly senses heat stress, pH changes, and hydrogen peroxide via the engagement of redox state
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Ke-Qin Zhang, Jing-Shi Deng, Juan Chen, Zefen Yu, Lemin Zhang, Cuixian Zhang, Lihong Guo, Xiaolu Li, Pengyuan Zhang, Yanfang Liu, and Wenpeng Li
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Hot Temperature ,DNA, Plant ,Physiology ,Arabidopsis ,Gene Expression ,Plant Science ,Genes, Plant ,Redox ,chemistry.chemical_compound ,Heat Shock Transcription Factors ,Gene Expression Regulation, Plant ,Stress, Physiological ,Heat shock protein ,Gene expression ,Genetics ,HSP70 Heat-Shock Proteins ,RNA, Messenger ,Amino Acids ,Promoter Regions, Genetic ,Hydrogen peroxide ,Heat-Shock Proteins ,Plant Proteins ,biology ,Arabidopsis Proteins ,Chemistry ,Hydrogen Peroxide ,Hydrogen-Ion Concentration ,biology.organism_classification ,Recombinant Proteins ,Hsp70 ,DNA-Binding Proteins ,Heat shock factor ,Oxidative Stress ,Biochemistry ,Biophysics ,Protein Multimerization ,Oxidation-Reduction ,Chromatin immunoprecipitation ,Heat-Shock Response ,Transcription Factors - Abstract
Arabidopsis heat shock factor HsfA1a is present in a latent, monomeric state under normal conditions; its activation involves heat stress-induced trimerization, binding to heat shock element in target promoters, and the acquisition of transcriptional competence. HsfA1a is an important regulator for heat stress-induced gene expression and thermotolerance. However, it is not clear whether HsfA1a is directly activated by stress and the mechanisms of the stress signaling are poorly understood. We analyzed HsfA1a activation by trimerization and DNA-binding assays in vitro and in vivo in response to heat stress, low/high pH, and hydrogen peroxide treatments. Our results show that purified recombinant HsfA1a was activated by these stress treatments in vitro. The same treatments also induced the binding to HSP18.2 and HSP70 promoters as examined by chromatin immunoprecipitation, and the HsfA1a DNA binding paralleled the mRNA expression of its target genes induced by different stresses. Stress-induced DNA-binding could be reversed, both in vitro and in vivo, by subsequent incubation with reducing agents (DTT, NADPH). These data suggest that HsfA1a can directly sense stress and become activated, and this process is dependent on the redox state. An N-terminal deletion of the amino acid residues from 48 to 74 negatively affected pH- and hydrogen peroxide-, but not heat-stress sensing.
- Published
- 2013
18. Synthesis of Mo-HMS and Its Catalytic Performance in Liquid Epoxidation of Propylene
- Author
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Lihong Guo, Yongxia Miao, and Xinli Yang
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Chemistry ,Organic chemistry ,General Chemistry ,Catalysis - Published
- 2013
19. The well-coordinated linkage between acidogenicity and aciduricity via insoluble glucans on the surface of Streptococcus mutans
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Xuesong He, Lihong Guo, Renate Lux, Wenyuan Shi, and Jeffrey S. McLean
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0301 basic medicine ,Sucrose ,Genetic Linkage ,Adaptation, Biological ,Virulence ,Article ,Microbiology ,Streptococcus mutans ,03 medical and health sciences ,chemistry.chemical_compound ,In vivo ,2.2 Factors relating to the physical environment ,Aetiology ,Adaptation ,Glucans ,Pathogen ,Glucan ,chemistry.chemical_classification ,Microbial Viability ,Multidisciplinary ,biology ,Gene Expression Profiling ,Bacterial ,Gene Expression Regulation, Bacterial ,Hydrogen-Ion Concentration ,Biological ,biology.organism_classification ,In vitro ,Infectious Diseases ,030104 developmental biology ,Gene Expression Regulation ,Solubility ,chemistry ,Biochemistry ,Protons ,Transcriptome ,Bacteria - Abstract
Streptococcus mutans is considered the principal cariogenic bacterium for dental caries. Despite the recognition of their importance for cariogenesis, the possible coordination among S. mutans’ main virulence factors, including glucan production, acidogenicity and aciduricity, has been less well studied. In the present study, using S. mutans strains with surface-displayed pH-sensitive pHluorin, we revealed sucrose availability- and Gtf functionality-dependent proton accumulation on S. mutans surface. Consistent with this, using a pH-sensitive dye, we demonstrated that both in vivo cell-produced and in vitro enzymatically synthesized insoluble glucans displayed proton-concentrating ability. Global transcriptomics revealed proton accumulation triggers the up-regulation of genes encoding functions involved in acid tolerance response in a glucan-dependent manner. Our data suggested that this proton enrichment around S. mutans could pre-condition the bacterium for acid-stress. Consistent with this hypothesis, we found S. mutans strains defective in glucan production were more acid sensitive. Our study revealed for the first time that insoluble glucans is likely an essential factor linking acidogenicity with aciduricity. The coordination of these key virulence factors could provide new insights on how S. mutans may have become a major cariogenic pathogen.
- Published
- 2015
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20. Effect of the calcination conditions on the NO storage behavior of the perovskite BaFeO3− catalysts
- Author
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Honghu Zou, Noritatsu Tsubaki, Zhiqiang Zou, Ming Meng, Lihong Guo, Xingang Li, Xingwen Zhang, and Hui Xian
- Subjects
Chemistry ,Inorganic chemistry ,Spinel ,General Chemistry ,engineering.material ,Heterogeneous catalysis ,Catalysis ,law.invention ,law ,engineering ,Noble metal ,Calcination ,NOx ,Perovskite (structure) ,Sol-gel - Abstract
The BaFeO 3− x perovskite catalyst was prepared by sol–gel method for NO x storage under lean-burn conditions. During the catalyst precursor calcination, a series of complex solid reactions happened, and the BaCO 3 , formed during citric acid combustion, played a key role to react with the spinel species achieving the aimed perovskite. On the Ba–Fe–750F catalyst, the perovskite phase and the small amount of spinel phase were evidenced by XRD, and some well dispersed carbonate was also detected by FT-IR. Under lean-burn conditions, the NO x was easily stored on the Ba–Fe–750F catalyst, and its optimized NO x storage capacity (NSC), i.e. 333.5 μmol g −1 , was obtained at 400 °C. At above 400 °C, the stored nitrate became unstable and decomposed, resulting in the sharp decrease of NSC. Two kinds of the NO x storage sites were identified by in situ DRIFTS experiments that the carbonate remaining on the catalyst could transform to monodentate nitrate, and the A site Ba in the perovskite structure could directly bind with NO x to form N-bounded nitrate. This BaFeO 3− x perovskite catalyst was a potential NO x storage material with noble metal free.
- Published
- 2010
21. Thermally activated delayed fluorescence organic dots for two-photon fluorescence lifetime imaging
- Author
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Junzi Li, Tingchao He, Shuyu Xiao, Lihong Guo, Junmin Zhang, Xiaodong Lin, Can Ren, Rui Chen, Wenbo Hu, Zhuohua Li, and Chuanxiang Ye
- Subjects
chemistry.chemical_classification ,Fluorescence-lifetime imaging microscopy ,Materials science ,Fluorophore ,Physics and Astronomy (miscellaneous) ,Carbazole ,Quantum yield ,02 engineering and technology ,Electron acceptor ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Photochemistry ,01 natural sciences ,Fluorescence ,0104 chemical sciences ,chemistry.chemical_compound ,Autofluorescence ,chemistry ,Molecule ,0210 nano-technology - Abstract
Autofluorescence is a major challenge in complex tissue imaging when molecules present in the biological tissue compete with the fluorophore. This issue may be resolved by designing organic molecules with long fluorescence lifetimes. The present work reports the two-photon absorption (TPA) properties of a thermally activated delayed fluorescence (TADF) molecule with carbazole as the electron donor and dicyanobenzene as the electron acceptor (i.e., 4CzIPN). The results indicate that 4CzIPN exhibits a moderate TPA cross-section (∼9 × 10−50 cm4 s photon−1), high fluorescence quantum yield, and a long fluorescence lifetime (∼1.47 μs). 4CzIPN was compactly encapsulated into an amphiphilic copolymer via nanoprecipitation to achieve water-soluble organic dots. Interestingly, 4CzIPN organic dots have been utilized in applications involving two-photon fluorescence lifetime imaging (FLIM). Our work aptly demonstrates that TADF molecules are promising candidates of nonlinear optical probes for developing next-generation multiphoton FLIM applications.
- Published
- 2018
22. Analysis of local polarity change around Cys34 in bovine serum albumin during N→B transition by a polarity-sensitive fluorescence probe
- Author
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Lihong Guo, Huimin Ma, and Xiaochun Wang
- Subjects
Protein Folding ,Circular dichroism ,Polarity (physics) ,Analytical chemistry ,Serum albumin ,Dielectric ,Analytical Chemistry ,Protein structure ,Animals ,Cysteine ,Bovine serum albumin ,Instrumentation ,Spectroscopy ,Fluorescent Dyes ,Molecular Structure ,biology ,Chemistry ,Circular Dichroism ,Serum Albumin, Bovine ,Hydrogen-Ion Concentration ,Fluorescence ,Atomic and Molecular Physics, and Optics ,Protein Structure, Tertiary ,Spectrometry, Fluorescence ,biology.protein ,Cattle ,Spectrophotometry, Ultraviolet ,Protein folding ,Hydrophobic and Hydrophilic Interactions - Abstract
The change trend of the local environment of Cys34 domain in bovine serum albumin has been studied as a function of pH value by using thiol-specific and polarity-sensitive fluorescent probe 3-(4-chloro-6-p-maleimidylphenoxyl-1,3,5-triazinylamino)-7-dimethylamino-2-methyl-phenazine. The local polarity of the Cys34 domain is found to rise with the increase of pH values, and the corresponding dielectric constant is raised from 12.8 at pH 6.0 to 23.3 at pH 9.1. The result shows that the environment of the Cys34 domain is rather hydrophobic in normal state at pH 6.0 and becomes a little hydrophilic in the course of N-->B transition, which may be attributed to the slight unfolding of the protein and thus the increasing of exposure of the previously relatively buried Cys34. In addition, the increased dielectric constant (23.3) is much lower than that (80.1) of water, suggesting that the unfolding of bovine serum albumin does not cause the full exposure of the Cys34 to the aqueous media during the transition.
- Published
- 2009
23. Nanoscale characterization of effect of L-arginine on Streptococcus mutans biofilm adhesion by atomic force microscopy
- Author
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Lihong Guo, Stacey Lavender, Latonya Kilpatrick-Liverman, James K. Gimzewski, JungReem Woo, Shivani Sharma, and Wenyuan Shi
- Subjects
Dental Plaque ,Dental Caries ,Polysaccharide ,Dental plaque ,Arginine ,Microscopy, Atomic Force ,Microbiology ,Bacterial Adhesion ,Extracellular matrix ,Streptococcus mutans ,Extracellular ,medicine ,Saliva ,Glucans ,chemistry.chemical_classification ,Mouth ,biology ,Chemistry ,Polysaccharides, Bacterial ,Biofilm ,Tooth surface ,Adhesion ,biology.organism_classification ,medicine.disease ,Extracellular Matrix ,Biochemistry ,Biofilms - Abstract
A major aetiological factor of dental caries is the pathology of the dental plaque biofilms. The amino acid l-arginine (Arg) is found naturally in saliva as a free molecule or as a part of salivary peptides and proteins. Plaque bacteria metabolize Arg to produce alkali and neutralize glycolytic acids, promoting a less cariogenous oral microbiome. Here, we explored an alternative and complementary mechanism of action of Arg using atomic force microscopy. The nanomechanical properties of Streptococcus mutans biofilm extracellular matrix were characterized under physiological buffer conditions. We report the effect of Arg on the adhesive behaviour and structural properties of extracellular polysaccharides in S. mutans biofilms. High-resolution imaging of biofilm surfaces can reveal additional structural information on bacterial cells embedded within the surrounding extracellular matrix. A dense extracellular matrix was observed in biofilms without Arg compared to those grown in the presence of Arg. S. mutans biofilms grown in the presence of Arg could influence the production and/or composition of extracellular membrane glucans and thereby affect their adhesion properties. Our results suggest that the presence of Arg in the oral cavity could influence the adhesion properties of S. mutans to the tooth surface.
- Published
- 2014
24. Recent Applications of Polyethylene Glycols (PEGs) and PEG Derivatives
- Author
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Daniela Hutanu, Lihong Guo, Costel C. Darie, and Mark D Frishberg
- Subjects
Medical device ,Drug development ,Chemistry ,Drug delivery ,Drug release ,Nanotechnology - Abstract
Numerous applications of polyethylene glycol derived polymers (PEGs) have been reported in the scientific literature for many years. With increasing experience and comfort by regulatory authorities, worldwide, in the utilization of these materials in drug and medical device applications, their use in a variety of research and development areas is expanding. This review will focus on just the range of applications of PEGs published in the first half of 2014 in the medical device, drug development, and diagnostics areas, including drug delivery, wound healing, cell culture models, and tissue regeneration.
- Published
- 2014
25. Free convection and surface kinetics in crystal growth from solution
- Author
-
James K. Baird and Lihong Guo
- Subjects
Gravity (chemistry) ,Sticking coefficient ,Natural convection ,Buoyancy ,Chemistry ,Diffusion ,General Physics and Astronomy ,Thermodynamics ,Crystal growth ,engineering.material ,Crystal ,Boundary layer ,engineering ,Physical and Theoretical Chemistry - Abstract
As a crystal grows from solution, there is ordinarily a boundary layer depleted in solute, which forms at the crystal–solution interface. When the normal to the growing crystal surface is oriented in any direction other than parallel to gravity, the boundary layer is set into motion by the force of buoyancy. Using a similarity transformation and a boundary layer approximation, we have solved the Navier–Stokes equation and the equation for convective diffusion for a crystal in the form of a flat plate growing with normal perpendicular to gravity. Parameters in the theory include solute concentration, c0, and diffusion coefficient, D; solution shear viscosity, μ, mass density, ρ, and logarithmic density derivative with respect to concentration, α; crystal solubility, cs, height, h, and linear growth rate, kG; the specific rate, k (sticking coefficient), of the reaction which transfers molecules from the solution to the crystal and the kinetic order, n, of this reaction; and the acceleration due to gravity, ...
- Published
- 1998
26. Preferential formation of the hydroperoxide of linoleic acid in choline glycerophospholipids in human erythrocytes membrane during peroxidation with an azo initiator
- Author
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Lihong Guo, Yasuhito Nakagawa, Tatsuo Shinozuka, Akira Ogamo, and Zhouluo Ou
- Subjects
Adult ,Linoleic acid ,Amidines ,Phospholipid ,Biochemistry ,Linoleic Acid ,chemistry.chemical_compound ,Ethanolamine ,Physiology (medical) ,Humans ,Choline ,Linoleic Acids, Conjugated ,Chromatography, High Pressure Liquid ,chemistry.chemical_classification ,Chromatography ,Phosphatidylethanolamines ,Erythrocyte Membrane ,Hydrogen Peroxide ,Membrane ,Linoleic Acids ,chemistry ,Glycerophospholipid ,Fatty Acids, Unsaturated ,Phosphatidylcholines ,lipids (amino acids, peptides, and proteins) ,Arachidonic acid ,Lipid Peroxidation ,Polyunsaturated fatty acid - Abstract
The formation of phospholipid hydroperoxides was monitored in human red blood cell (RBC) membranes that had been peroxidized with an azo initiator. Peroxidation of RBC membranes caused a profound decrease in the amount of polyunsaturated fatty acids and concomitantly hydroperoxides, as primary products of peroxidation, appeared in the phospholipids. Hydroperoxides were predominantly generated in choline glycerophospholipid (CGP), while the extent of formation of ethanolamine glycerophospholipid (EGP) hydroperoxides was low and their presence was transient. Hydroxy and hydroperoxy moieties in CGP were identified as 9-hydroxy and 13-hydroxy octadecanoic acid, derived from linoleic acid, by gas chromatography-mass spectrometric analysis. No consistent generation of hydroperoxide from arachidonic acid was evident in CGP. The CGP-hydroperoxide accounted for approximately 76% of linoleic acid consumed during peroxidation of RBC membranes. The prominent generation of phospholipid hydroperoxides was observed in the linoleic acid-rich membranes from rabbit RBC, indicating that the level of linoleic acid in phospholipids determines, in part, the extent of formation of phospholipid hydroperoxides. Aldehydic phospholipids, as secondary products of peroxidation, were detected in oxidized membranes. EGP was the most prominent aldehydic phospholipid, while negligible amounts of aldehydic CGP were formed. This study indicates that the process of oxidation of individual phospholipids clearly differs among phospholipids and depends on the structure of each.
- Published
- 1995
27. Conjugation of low molecular weight poly(ethylene glycol) to biphalin enhances antinociceptive profile
- Author
-
Jason D. Huber, Thomas P. Davis, Lihong Guo, Michael D. Bentley, Richard D. Egleton, Chris R. Campos, Roberts Michael J, and Ken A. Witt
- Subjects
Male ,Analgesics ,Mice, Inbred ICR ,Stereochemistry ,technology, industry, and agriculture ,Pharmaceutical Science ,(+)-Naloxone ,Enkephalins ,Pharmacology ,Biphalin ,Polyethylene Glycols ,chemistry.chemical_compound ,Mice ,chemistry ,Naltrindole ,PEG ratio ,medicine ,Morphine ,Potency ,Animals ,Ethylene glycol ,Tail flick test ,medicine.drug ,Pain Measurement - Abstract
The objectives of this study were to examine the effect of poly(ethylene glycol) (PEG) conjugation on the tyrosine residues of biphalin to determine the proper size PEG for optimal efficacy and investigate the antinociceptive profile of PEG-biphalin against biphalin via three routes of administration. All antinociception evaluations were made using a radiant-heat tail flick analgesia meter. (2 kDa)(2) PEG-biphalin was identified as the optimal size of PEG to enhance the antinociceptive profile following intravenous administration of 685 nmol kg(-1) of biphalin or PEG-biphalin [(1 kDa)(2), (2 kDa)(2), (5 kDa)(2), (12 kDa)(2), (20 kDa)(2)]. (2 kDa)(2) PEG-biphalin displayed an area under the curve (AUC) approximately 2.5 times that of biphalin with enhanced analgesia up to 300 min postinjection. (2 kDa)(2) PEG-biphalin was equipotent to biphalin following intracerebroventricular administration (0.4 nmol kg(-1)). Both biphalin and (2 kDa)(2) PEG-biphalin were effectively antagonized with naloxone (10 mg kg(-1)) and a partial antagonistic effect was seen following pretreatment with naltrindole (20 mg kg(-1)). (2 kDa)(2) PEG-biphalin showed significantly increased potency (A(50)) when administered intravenously and subcutaneously. Additionally, (2 kDa)(2) PEG-biphalin demonstrated a significantly enhanced antinociceptive profile (AUC) via all routes of administration tested. These findings indicate that PEG conjugation to biphalin retains opioid-mediated effects observed with biphalin and is a valuable tool for eliciting potent, sustained analgesia via parenteral routes of administration.
- Published
- 2003
28. Identification and quantitation of choline glycerophospholipids that contain aldehyde residues by fluorometric high-performance liquid chromatography
- Author
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Lihong Guo, Akira Ogamo, Yasuhito Nakagawa, Yaeko Konda, Yoshihiro Harigaya, and Zhouluo Ou
- Subjects
Biophysics ,Fractionation ,Biochemistry ,High-performance liquid chromatography ,Aldehyde ,Sensitivity and Specificity ,chemistry.chemical_compound ,medicine ,Organic chemistry ,Humans ,Fluorometry ,Derivatization ,Molecular Biology ,Chromatography, High Pressure Liquid ,chemistry.chemical_classification ,Aldehydes ,Chromatography ,Chemistry ,Microchemistry ,Erythrocyte Membrane ,Cell Biology ,Fluorescence ,Red blood cell ,Membrane ,medicine.anatomical_structure ,Reagent ,Phosphatidylcholines ,Oxidation-Reduction - Abstract
A high-performance liquid chromatographic method was established for the fractionation of oxidized choline glycerophospholipids (CGPs) that contain aldehyde residues, after their derivatization with a fluorescent reagent 4-(N,N-dimethylaminosulfonyl)-7-hydrazino-2,1,3-benzoxadiazole (DBD-H). DBD-H efficiently reacted with the aldehyde residues of phospholipids at room temperature. Fluorescent derivatives of aldehydic phospholipids were well separated into species that contained aldehyde groups at different sites. The relationship between the amount of each derivative and the signal was linear over a wide range and amounts as low as several picomoles of aldehydic CGP could be detected. This method is applicable to the quantitation of aldehydic phospholipids in peroxidized membranes of red blood cells. In the present study, formation of aldehydic choline glycerophospholipids was demonstrated for the first time in peroxidized red blood cell membranes and the compounds were quantitated.
- Published
- 1995
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