128 results on '"Shun Wan"'
Search Results
2. A Novel Probiotic-Based Oral Vaccine against SARS-CoV-2 Omicron Variant B.1.1.529
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Eddie Chung Ting Chau, Tsz Ching Kwong, Chun Keung Pang, Lee Tung Chan, Andrew Man Lok Chan, Xiaoqiang Yao, John Siu Lun Tam, Shun Wan Chan, George Pak Heng Leung, William Chi Shing Tai, and Yiu Wa Kwan
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Omicron ,Lactobacillus casei ,oral vaccine ,infectious disease ,COVID-19 ,Biology (General) ,QH301-705.5 ,Chemistry ,QD1-999 - Abstract
COVID-19 pandemic, caused by the SARS-CoV-2 virus, is still affecting the entire world via the rapid emergence of new contagious variants. Vaccination remains the most effective prevention strategy for viral infection, yet not all countries have sufficient access to vaccines due to limitations in manufacturing and transportation. Thus, there is an urgent need to develop an easy-to-use, safe, and low-cost vaccination approach. Genetically modified microorganisms, especially probiotics, are now commonly recognized as attractive vehicles for delivering bioactive molecules via oral and mucosal routes. In this study, Lactobacillus casei has been selected as the oral vaccine candidate based on its’ natural immunoadjuvant properties and the ability to resist acidic gastric environment, to express antigens of SARS-CoV-2 Omicron variant B.1.1.529 with B-cell and T-cell epitopes. This newly developed vaccine, OMGVac, was shown to elicit a robust IgG systemic immune response against the spike protein of Omicron variant B.1.1.529 in Golden Syrian hamsters. No adverse effects were found throughout this study, and the overall safety was evaluated in terms of physiological and histopathological examinations of different organs harvested. In addition, this study illustrated the use of the recombinant probiotic as a live delivery vector in the initiation of systemic immunity, which shed light on the future development of next-generation vaccines to combat emerging infectious diseases.
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- 2023
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3. A Fully Integrated 3.5-/4.9-GHz Dual-Band GaN MMIC Doherty Power Amplifier Based on Multi-Resonant Circuits
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Fadhel M. Ghannouchi, Zhenghe Feng, Xiaofan Chen, Guansheng Lv, Wenhua Chen, and Shun Wan
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Radiation ,Materials science ,business.industry ,Amplifier ,Transistor ,Adjacent channel power ratio ,Gallium nitride ,Condensed Matter Physics ,Characteristic impedance ,Predistortion ,law.invention ,chemistry.chemical_compound ,chemistry ,law ,Optoelectronics ,Electrical and Electronic Engineering ,business ,Monolithic microwave integrated circuit ,Electronic circuit - Abstract
In this article, a fully integrated dual-band gallium nitride (GaN) Doherty power amplifier (DPA) based on multi-resonant circuits (MRCs) is presented. A lumped T-type network in combination with the output capacitances of the main and auxiliary transistors is able to realize the quarter-wavelength transformer (QWT) in DPA, and its component values are totally decided by the operating frequency, given a certain characteristic impedance. MRCs are proposed to exhibit the required component values at two different frequencies. By replacing each component in the T-type network with an MRC, a dual-band QWT can be achieved. An integrated dual-band DPA is implemented in a commercial 0.25-μm GaN-HEMT process to validate the proposed method. The fabricated DPA shows a saturated output power of 43.8-44.7/44.4-44.8 dBm, a 6-dB back-off drain efficiency (DE) of 41%-46%/41.5%-47%, and a saturated DE of 49%-52%/56%-59% in 3.35-3.6/4.8-5.2 GHz, with a compact size of 2.8 x 3.5 mm². Applying a 100-MHz OFDM signal with a 7.8-dB peak-to-average power ratio (PAPR), an average efficiency of 37%/40% and an average power of 37/37 dBm are measured at 3.5/5.0 GHz, and the adjacent channel power ratio (ACPR) is better than -49 dBc after digital predistortion (DPD). To the best of our knowledge, the proposed DPA is the first demonstration of fully integrated dual-band GaN DPAs.
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- 2022
4. Evolution of Structural and Electronic Properties in NbTe2 under High Pressure
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Yanju Wang, Shun Wan, Nana Li, Hongliang Dong, Wen Deng, Resta A. Susilo, Bin Chen, Mingqiang Hou, Chunxiao Gao, Qing Dong, Shujia Li, and Jiajia Feng
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Phase transition ,Condensed matter physics ,Field (physics) ,Electronic correlation ,010405 organic chemistry ,Chemistry ,Stacking ,Electron ,010402 general chemistry ,01 natural sciences ,0104 chemical sciences ,Inorganic Chemistry ,Transition metal ,Condensed Matter::Strongly Correlated Electrons ,Charge carrier ,Physical and Theoretical Chemistry ,Charge density wave - Abstract
Transition metal dichalcogenides (TMDs) have attracted wide attention due to their quasi-two-dimensional layered structure and exotic properties. Plenty of efforts have been done to modulate the interlayer stacking manner for novel states. However, as an equally important element in shaping the unique properties of TMDs, the effect of intralayer interaction is rarely revealed. Here, we report a particular case of pressure-tuned re-arrangement of intralayer atoms in distorted 1T-NbTe2, which was demonstrated to be a new type of structural phase transition in TMDs. The structural transition occurs in the pressure range of 16-20 GPa, resulting in a transformation of Nb atomic arrangement from the trimeric to dimeric structure, accompanied by a dramatic collapse of unit cell volume and lattice parameters. Simultaneously, a charge density wave (CDW) was also found to collapse during the phase transition. The strong increase in the critical fluctuations of CDW induces a significant decline in the electronic correlation and a change of charge carrier type from hole to electron in NbTe2. Our finding reveals a new mechanism of structure evolution and expands the field of pressure-induced phase transition.
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- 2021
5. Grain-size gradient structure by abnormal grain growth
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Bin Chen, Hongliang Dong, Junpu Wang, Zhiqiang Chen, Jinling Liu, He Li, Shun Wan, Haikuo Wang, Mingzhi Yuan, Duanwei He, and Resta A. Susilo
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Materials science ,Sintering ,chemistry.chemical_element ,02 engineering and technology ,Abnormal grain growth ,Tungsten ,Pole figure ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Grain size ,0104 chemical sciences ,Shear modulus ,chemistry ,General Materials Science ,Crystallite ,Composite material ,0210 nano-technology ,Ductility - Abstract
We report a novel method to synthesize bulk grain-size gradient polycrystalline Ni by AGG. By periodical sintering in the large volume press (LVP), AGG repeatedly occurs, resulting in exceptionally large grains on the sample surface, but the inner grains are still small. The formation of grain-size gradient profile is attributed to the uneven plastic deformation caused by compression in the LVP. Besides, the gradient structure can be achievable with uniformity by employing tungsten with a high shear modulus into the sample assembly. This work would guide us to design bulk heterogeneous gradient nanostructured materials with both excellent strength and ductility. The uniform grained gradient structure obtained with the improved LVP assembly. (a) The improved LVP assembly with W tablet used between Ni sample and outer Mo-capsule; (b) Inverse pole figure mapping characterization of uniform grain-size gradient structure comprised of smaller grains.
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- 2021
6. Highly C2/C1-Selective Covalent Organic Frameworks Substituted with Azo Groups
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Shun Wan, Shaofeng Huang, Wei Zhang, Sadegh Yazdi, Li-Li Tan, Yiming Hu, and Yinghua Jin
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Materials science ,010405 organic chemistry ,Imine ,010402 general chemistry ,01 natural sciences ,0104 chemical sciences ,Crystallinity ,chemistry.chemical_compound ,Adsorption ,chemistry ,Covalent bond ,Polymer chemistry ,Molecule ,General Materials Science ,Gas separation ,Selectivity ,Covalent organic framework - Abstract
A series of covalent organic frameworks substituted with azo groups (AzoCOFs) have been synthesized via imine condensation. The obtained frameworks show crystallinity and high stability. More importantly, the AzoCOFs exhibit exceptionally high ideal adsorption solution theory (IAST) selectivity in adsorption of C2H2 (35-2891) over CH4 at 273 K and 1 bar, owing to the favorable interactions between azo groups and acetylene molecules. The dependence of the gas adsorption property on pore size and polarity of the frameworks was also studied. The triethylene glycol substituted Tg-AzoCOF shows the highest C2H2/CH4 selectivity (IAST selectivity of 2891), which represents the highest reported for all porous materials. The AzoCOFs also exhibit high IAST adsorption selectivity of C2H4/CH4 (11-20), C2H6/CH4 (15-22), and CO2/CH4 (12-37), which is comparable with most porous materials, thus showing their great potential in gas separation applications.
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- 2020
7. Covalent organic framework-supported platinum nanoparticles as efficient electrocatalysts for water reduction
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Wei Zhang, Yiming Hu, Joshua Jack, Shun Wan, Shaofeng Huang, Zhiyong Ren, Sadegh Yazdi, Pin Ching Maness, Yinghua Jin, and Eunsol Park
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Reaction rate ,Hydrogen ,chemistry ,Chemical engineering ,Hydride ,chemistry.chemical_element ,General Materials Science ,Platinum nanoparticles ,Redox ,Faraday efficiency ,Catalysis ,Covalent organic framework - Abstract
The hydrogen evolution reaction (HER) is one of the most effective and sustainable ways to produce hydrogen gas as an alternative clean fuel. The rate of this electrocatalytic reaction is highly dependent on the properties (dispersity and stability) of electrocatalysts. Herein, we developed well-dispersed and highly stable platinum nanoparticles (PtNPs) supported on a covalent organic framework (COF-bpyTPP), which exhibit excellent catalytic activities toward HER as well as the hydride reduction reaction. The nanoparticles have an average size of 2.95 nm and show superior catalytic performance compared to the commercially available Pt/C under the same alkaline conditions, producing 13 times more hydrogen with a far more positive onset potential (−0.13 V vs. −0.63 V) and ca. 100% faradaic efficiency. The reaction rate of the hydride reduction of 4-nitrophenol was also 10 times faster in the case of PtNPs@COF compared to the commercial Pt/C under the same loading and conditions. More importantly, the PtNPs@COF are highly stable under the aqueous reactions conditions and can be reused without showing noticeable aggregation and activity degradation.
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- 2020
8. TNF-ɑ Induces Methylglyoxal Accumulation in Lumbar Herniated Disc of Patients With Radicular Pain
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Xinsheng Zhang, Xiaogang Wang, Liang Gao, Bin Yang, Yahan Wang, Kerun Niu, Jiahui Lai, Shun Wan, and Jianping Luo
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musculoskeletal diseases ,medicine.medical_specialty ,GLO1 ,Nerve root ,Cognitive Neuroscience ,Neurosciences. Biological psychiatry. Neuropsychiatry ,Stimulation ,Mechanical Allodynia ,lumbar disc herniation ,chemistry.chemical_compound ,Behavioral Neuroscience ,Lumbar ,TNF-ɑ ,Internal medicine ,methylglyoxal ,medicine ,pain ,Original Research ,business.industry ,Methylglyoxal ,medicine.disease ,Endocrinology ,Neuropsychology and Physiological Psychology ,chemistry ,Radicular pain ,Tumor necrosis factor alpha ,Lumbar disc herniation ,business ,RC321-571 - Abstract
Lumbar disc herniation (LDH) with radicular pain is a common and complicated musculoskeletal disorder. Our previous study showed that LDH-induced methylglyoxal (MG) accumulation contributed to radicular pain. The underlying mechanisms through which MG accumulates are poorly understood. In the present study, we found that both MG and tumor necrosis factor-alpha (TNF-ɑ) levels in the herniated disc of patients with radicular pain were significantly increased, and the activity of Glyoxalase 1 (GLO1), the rate-limiting enzyme that metabolizes MG, was decreased. In rats, the LDH model was mimicked by implantation of autologous nucleus pulposus (NP) to the left lumbar five spinal nerve root. The mechanical allodynia was observed in LDH rats. Besides, MG and TNF-ɑ levels were increased, and GLO1 activity was significantly decreased in the implanted NP. In cultured rat NP cells, stimulation with the inflammatory mediator TNF-ɑ reduced GLO1 activity and expression. These results suggested that TNF-ɑ-induced GLO1 activity decrease contributed to MG accumulation in the herniated disc of patients with radicular pain.
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- 2021
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9. Crystalline Lithium Imidazolate Covalent Organic Frameworks with High Li-Ion Conductivity
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Nathan Dunlap, Se-Hee Lee, Shuanglong Lu, Yiming Hu, Isaac Sellinger, Yinghua Jin, Wei Zhang, Shun Wan, Michael Ortiz, and Shaofeng Huang
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Chemistry ,Ionic bonding ,chemistry.chemical_element ,General Chemistry ,Electrolyte ,Activation energy ,Conductivity ,010402 general chemistry ,01 natural sciences ,Biochemistry ,Catalysis ,0104 chemical sciences ,Ion ,Crystallography ,chemistry.chemical_compound ,Colloid and Surface Chemistry ,Covalent bond ,Imidazolate ,Lithium - Abstract
Ionic covalent organic frameworks (ICOFs) have recently emerged as promising candidates for solid-state electrolytes. Herein, we report the first example of a series of crystalline imidazolate-containing ICOFs as single-ion conducting COF solid electrolyte materials, where lithium cations freely travel through the intrinsic channels with outstanding ion conductivity (up to 7.2 × 10-3 S cm-1) and impressively low activation energy (as low as 0.10 eV). These properties are attributed to the weak Li ion-imidazolate binding interactions and well-defined porous 2D framework structures of such ICOFs. We also investigated the structure-property relationship by varying the electronic properties of substituents (electron donating/withdrawing) that covalently attached to the imidazolate groups. We found electron-withdrawing substituents significantly improve the ion-conducting ability of imidazolate-ICOF by weakening ion-pair interactions. Our study provides a convenient bottom-up approach toward a novel class of highly efficient single-ion conducting ICOFs which could be used in all solid-state electrolytic devices.
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- 2019
10. Highly Fluoro-Substituted Covalent Organic Framework and Its Application in Lithium–Sulfur Batteries
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Guipeng Yu, Wei Zhang, Kai Han, De-Gao Wang, Yiming Hu, Min Song, Shun Wan, Weifeng Wei, Yinghua Jin, Nuo Li, and Gui-Chao Kuang
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inorganic chemicals ,Materials science ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Electrochemistry ,01 natural sciences ,Sulfur ,Cathode ,0104 chemical sciences ,Amorphous solid ,law.invention ,Chemical kinetics ,chemistry ,Chemical engineering ,Physisorption ,law ,Nucleophilic aromatic substitution ,General Materials Science ,0210 nano-technology ,Covalent organic framework - Abstract
We report the preparation of a highly fluoro-substituted crystalline covalent organic framework (COF) and its application as a cathode material in lithium-sulfur batteries (LSBs) upon sulfur confinement. A sulfur-functionalized COF with high sulfur content (60 wt %) was obtained through physisorption of elemental sulfur and subsequent SNAr reaction of sulfur with aromatic fluorides on the COF backbone. After such physical and chemical confinement of sulfur through a postfunctionalization approach, the COF material still shows some structural order, allowing us to investigate the structure-property relationship of such COF materials in LSB application. We compared the electrochemical performances of the two cathode materials prepared from a crystalline COF and its amorphous counterpart and studied the important factors that affect battery capacity, reaction kinetics, and cycling stability.
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- 2018
11. A Review on Catalytic Progress of Polysulfide Redox Reactions on Transition Metal Sulfides in Li‐S Batteries from Structural Perspective
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Haocheng Li, Xueyu Wang, Hongwei Ma, Daying Guo, Lianhui Wu, Huile Jin, Xi'an Chen, and Shun Wang
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Li−S batteries ,transition metal sulfides ,heterojunction ,catalytic conversion ,shuttle effect ,Industrial electrochemistry ,TP250-261 ,Chemistry ,QD1-999 - Abstract
Abstract The commercialization of Li−S batteries is seriously hindered by polysulfides with severe shuttle effect, and the inherent insulating properties and slow reaction kinetics of insoluble Li2S products. Transition metal sulfides (TMSs) have a high adsorption capacity for polysulfides and have been shown to have a strong catalytic effect on polysulfide conversion reactions. This paper reviews the research on the application of Unary TMSs, heterostructures, etc. in Li−S batteries, and gives some research methods for TMD catalysts in Li−S batteries. Finally, it points out the main focuses and direction of future Li−S battery research and development. It aims to provide some insights into the design and manufacture of advanced Li−S batteries for commercial use.
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- 2024
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12. Abnormal Grain Growth: A Potential Way to Construct Gradient Structure
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Bin Chen, Duanwei He, Jinling Liu, Junpu Wang, Resta A. Susilo, Shun Wan, Hongliang Dong, Haikuo Wang, He Li, and Mingzhi Yuan
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Shear modulus ,Work (thermodynamics) ,Nickel ,Materials science ,chemistry ,food and beverages ,chemistry.chemical_element ,Sintering ,Composite material ,Abnormal grain growth ,Tungsten ,Deformation (engineering) ,Ductility - Abstract
Abnormal grain growth (AGG) has been commonly observed but the mechanism still remains unclear. In this study, the formation of abnormally large grains was investigated in compressed nickel powders. By periodical sintering in the large volume press, AGG occurred and resulted in a gradient coarse-grained structure. Through the improvement of the cell assembly by introducing tungsten tablets with a higher shear modulus, the optimized grained gradient structure can be obtained, which arises from tuning the AGG associated with the suppress of deformation. This work would be a potential way to design heterogeneous gradient nanostructured materials with excellent strength and ductility.
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- 2020
13. NLRP1 deficiency attenuates diabetic retinopathy (DR) in mice through suppressing inflammation response
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Xin-Shun Wan, Chang Liu, Shao-Wei Li, and Yan Li
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Male ,Retinal Ganglion Cells ,0301 basic medicine ,medicine.medical_specialty ,Inflammasomes ,Biophysics ,Inflammation ,Fructose ,Biochemistry ,Retinal ganglion ,Retina ,Streptozocin ,Diabetes Mellitus, Experimental ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Internal medicine ,medicine ,Animals ,Humans ,Receptor ,Molecular Biology ,Adaptor Proteins, Signal Transducing ,Mice, Knockout ,Diabetic Retinopathy ,business.industry ,Inflammasome ,Retinal ,Cell Biology ,Diabetic retinopathy ,medicine.disease ,Streptozotocin ,Mice, Inbred C57BL ,Vascular endothelial growth factor ,030104 developmental biology ,Endocrinology ,chemistry ,030221 ophthalmology & optometry ,Cytokines ,medicine.symptom ,Apoptosis Regulatory Proteins ,business ,medicine.drug - Abstract
Diabetic retinopathy (DR) is the common cause of diabetic vascular complications. The NOD-like receptor (NLR) family, pyrin domain containing 1 (NLRP1), also known as NALP1, inflammasome is the first member of the NLR family to be discovered, playing an important role in inflammatory response. However, its effect on DR development has not been reported. In the study, the wild type (WT) and NLRP1−/− mice were injected with streptozotocin (STZ) to induce DR. The results indicated that NLRP1−/− significantly increased bodyweight reduction and decreased blood glucose levels induced by STZ. WT/DR mice exhibited higher levels of NLRP1 in retinas. NLRP1−/− ameliorated retinal abnormalities in DR mice using H&E staining. In addition, attenuated avascular areas and neovascular tufts were also observed in NLRP1−/−/DR mice. The levels of pro-inflammatory cytokines in serum and retinas were highly induced in WT/DR mice, whereas being markedly reduced by NLRP1−/−. In addition, vascular endothelial growth factor (VEGF) and Iba1 expressions induced by STZ in serum or retinas were significantly down-regulated in NLRP1−/−/DR mice. Consistently, NLRP1−/− attenuated ASC and Caspase-1 expressions in retinas of DR mice. Compared to WT/DR group, NLRP1−/− markedly decreased retina p-nuclear factor-κB (NF-κB), interleukin-1β (IL-1β) and IL-18 levels. And similar results were confirmed in vitro that suppressing NLRP1/ASC inflammasome ameliorated inflammatory response in fructose-treated retinal ganglion cells. The results above indicated that the modulation of NLRP1 inflammasome might be a promising strategy for DR therapy.
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- 2018
14. Coordination-supported organic polymers: mesoporous inorganic–organic materials with preferred stability
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Caili Huang, Shize Yang, Hui Li, Sheng Dai, Shun Wan, Pengfei Zhang, Dong Chen, and Qianrong Fang
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chemistry.chemical_classification ,Condensation polymer ,Materials science ,Imine ,02 engineering and technology ,Polymer ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Inorganic Chemistry ,chemistry.chemical_compound ,Chemical engineering ,chemistry ,Boiling ,Inorganic organic ,0210 nano-technology ,Mesoporous material ,Imide ,Porosity - Abstract
A simple and versatile strategy, borrowing ideas from the chemistry of MOFs and COFs, is developed for the synthesis of coordination-supported organic polymers (COPs) via coordination between Al3+ and 5-amino-8-hydroxyquinoline together with organic imine- or imide-based polycondensation. The COPs with high surface areas (up to 1123 m2 g−1) and abundant mesopores (2.5 nm or 14 nm) possess good crystalline and porous structure after being soaked in boiling water.
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- 2018
15. One-pot preparation of arylalkynes by a tandem catalytic iodination of arenes and palladium-catalyzed coupling of iodoarenes with terminal alkynes
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Shun Wan, Sunewang R. Wang, and Wenjun Lu
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Bismuth -- Chemical properties ,Biological sciences ,Chemistry - Abstract
Iodination of activated arenes by air-oxidation is carried out in the presence of catalytic bismuth salts at room temperature. Subsequently, the formed iodoarenes react with terminal alkynes to give arylalkynes under a selected palladium-catalyzed coupling condition in the same pot.
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- 2006
16. Synthesis of Ultrafine and Highly Dispersed Metal Nanoparticles Confined in a Thioether-Containing Covalent Organic Framework and Their Catalytic Applications
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Hongwei Gu, Shuanglong Lu, Yiming Hu, Wei Zhang, Yinghua Jin, Shun Wan, and Ryan McCaffrey
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Dispersity ,Metal Nanoparticles ,Nanotechnology ,02 engineering and technology ,Sulfides ,010402 general chemistry ,01 natural sciences ,Biochemistry ,Catalysis ,Coupling reaction ,Nanomaterials ,Nitrophenols ,chemistry.chemical_compound ,Nitrophenol ,Colloid and Surface Chemistry ,Thioether ,Metal-Organic Frameworks ,General Chemistry ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,chemistry ,Chemical engineering ,Covalent bond ,0210 nano-technology ,Covalent organic framework - Abstract
Covalent organic frameworks (COFs) with well-defined and customizable pore structures are promising templates for the synthesis of nanomaterials with controllable sizes and dispersity. Herein, a thioether-containing COF has been rationally designed and used for the confined growth of ultrafine metal nanoparticles (NPs). Pt or Pd nanoparticles (Pt NPs and Pd NPs) immobilized inside the cavity of the COF material have been successfully prepared at a high loading with a narrow size distribution (1.7 ± 0.2 nm). We found the crystallinity of the COF support and the presence of thioether groups inside the cavities are critical for the size-controlled synthesis of ultrafine NPs. The as-prepared COF-supported ultrafine Pt NPs and Pd NPs show excellent catalytic activity respectively in nitrophenol reduction and Suzuki-Miyaura coupling reaction under mild conditions and low catalyst loading. More importantly, they are highly stable and easily recycled and reused without loss of their catalytic activities. Such COF-supported size-controlled synthesis of nanoparticles will open a new frontier on design and preparation of metal NP@COF composite materials for various potential applications, such as catalysis and development of optical and electronic materials.
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- 2017
17. MiR-410-3p activates the NF-κB pathway by targeting ZCCHC10 to promote migration, invasion and EMT of colorectal cancer
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Zeng-Hui Ma, Pei-Dong Shi, and Bo-Shun Wan
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0301 basic medicine ,Epithelial-Mesenchymal Transition ,Colorectal cancer ,Immunology ,medicine.disease_cause ,Biochemistry ,Cell Line ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Western blot ,Cell Movement ,Cell Line, Tumor ,medicine ,Humans ,Immunology and Allergy ,Neoplasm Invasiveness ,Molecular Biology ,Cell Proliferation ,Gene knockdown ,Reporter gene ,medicine.diagnostic_test ,NF-kappa B ,Zinc Fingers ,NF-κB ,Cell migration ,Hematology ,HCT116 Cells ,medicine.disease ,digestive system diseases ,Gene Expression Regulation, Neoplastic ,MicroRNAs ,030104 developmental biology ,chemistry ,030220 oncology & carcinogenesis ,Cancer research ,Signal transduction ,Colorectal Neoplasms ,Carcinogenesis ,HT29 Cells ,Signal Transduction - Abstract
Background Colorectal cancer (CRC) is a prevalent malignancy of the digestive tract. miR-410-3p is involved in oncogenesis and development of CRC, but the specific regulation mechanism is still not known clearly. Methods The expression of miR-410-3p and zinc finger CCHC-type containing 10 (ZCCHC10) in CRC cells was detected by qRT-PCR and western blot method, respectively. The dual-luciferase reporter gene detection was applied for determination of interaction between miR-410-3p and ZCCHC10. The wound healing assay and transwell assay were carried out to measure cell migration and invasive ability, respectively. Results The miR-410-3p expression levels were markedly increased, but ZCCHC10 levels were reduced in CRC cells and tissues. Dual-luciferase reporter gene detection indicated that miR-410-3p targeted ZCCHC10 directly. Functionally knockdown of ZCCHC10 or overexpression of miR-410-3p activated nuclear factor-κB (NF-κB) signaling pathway, promoted epithelial-mesenchymal transition (EMT) process, as well as cell migration and invasion of CRC cells. After adding NF-κB inhibitor BAY 11-708 to inhibit NF-κB pathway, the promoting effects of si-ZCCHC10 on cell migration, invasion and EMT of HT29 and SW480 cells were suppressed. Meanwhile, overexpression of ZCCHC10 inhibited the effects of miR-410-3p on cell migration, invasion and EMT of HT29 and SW480. Conclusion miR-410-3p-mediated ZCCHC10 suppression regulates NF-κB activation, thereby promoting EMT process, cell migration and invasion of CRC cells. This study provides a new insight into the specific mechanism by which miR-410-3p mediates CRC progression.
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- 2021
18. Cholesterol-lowering effects of piceatannol, a stilbene from wine, using untargeted metabolomics
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Meng-heng Li, Daniel K. W. Mok, Huan Zhang, Chi-On Chan, Shun Wan Chan, and Tung-Ting Sham
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0301 basic medicine ,medicine.drug_class ,Metabolite ,Linoleic acid ,Medicine (miscellaneous) ,Cholesterol 7 alpha-hydroxylase ,UPLC-MS ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Hyperlipidemia ,medicine ,Metabolomics ,TX341-641 ,Food science ,Piceatannol ,chemistry.chemical_classification ,Nutrition and Dietetics ,Bile acid ,Nutrition. Foods and food supply ,GC-MS ,Fatty acid ,Polyphenols ,medicine.disease ,030104 developmental biology ,chemistry ,Biochemistry ,030220 oncology & carcinogenesis ,Arachidonic acid ,lipids (amino acids, peptides, and proteins) ,Food Science - Abstract
This study aims at examining the hypolipidemic effect of piceatannol on high fat diet (HFD)-induced hypercholesterolemic Sprague-Dawley rats and serum metabolite changes. Piceatannol supplement significantly lowered the total cholesterols, low density lipoprotein cholesterol levels and the atherogenic index as compared to the HFD model which only have increased dietary cholesterol intake. Using untargeted mass spectrometry-based metabolomic platforms, multivariate statistics revealed that HFD significantly perturbed fatty acids, lysophospholipids, bile acids and conjugated bile acids. Reduced CYP7A1 protein expression and increase in glycocholate and taurodeoxycholate after piceatannol treatment suggested the conjugated bile acid might contribute to the cholesterol-lowering effect. For lipid profiles, lysoPC (20:2) and lysoPC (20:0) were decreased while the ratio of esterified arachidonic acid to esterified dihomo-γ linoleic acid was up-regulated for rats after piceatannol supplement. These results indicated that the therapeutic effect of piceatannol is associated with bile acid and fatty acid metabolisms and reduced absorption of dietary cholesterols.
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- 2017
19. A titanium-based porous coordination polymer as a catalyst for chemical fixation of CO2
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Yinghua Jin, Haishen Yang, Shun Wan, Wei Zhang, and Ya Du
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chemistry.chemical_classification ,Materials science ,010405 organic chemistry ,Renewable Energy, Sustainability and the Environment ,Coordination polymer ,Inorganic chemistry ,chemistry.chemical_element ,General Chemistry ,Polymer ,010402 general chemistry ,Heterogeneous catalysis ,01 natural sciences ,Cycloaddition ,0104 chemical sciences ,Catalysis ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,Alkoxide ,General Materials Science ,Porosity ,Titanium - Abstract
A novel type of porous coordination polymer with titanium alkoxide linkages (Ti-PCP) was successfully constructed through reaction of a 1,3-diol-substituted shape-persistent arylene–ethynylene macrocycle with Ti(OiPr)4. The polymer exhibits a high Brunauer–Emmett–Teller (BET) surface area (1029 m2 g−1) and good adsorption selectivity for CO2 over N2. With n-Bu4NBr as a co-catalyst, Ti-PCP can serve as a highly efficient catalyst to convert CO2 into cyclocarbonates through the cycloaddition reaction with epoxides under mild conditions. This framework-based heterogeneous catalyst not only has excellent catalytic activity, but also can be recycled and reused many times with easy product separation, thus showing its great potential for industrial applications as a green catalyst. With high uptake of CO2 and catalytic ability to convert CO2 to useful chemical compounds, this type of porous polymer with embedded catalytic centers could have important applications to solve environmental problems regarding post-combustion CO2 capture and conversion.
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- 2017
20. Inhibition of human equilibrative nucleoside transporters by 4-((4-(2-fluorophenyl)piperazin-1-yl)methyl)-6-imino-N-(naphthalen-2-yl)-1,3,5-triazin-2-amine
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George P.H. Leung, Shun Wan Chan, Chung Ming Tse, Philip Chiu Tsun Tang, Rachel Wai Sum Li, Simon Ming-Yuen Lee, Maggie Pui Man Hoi, Cui Yang, and Yiu Wa Kwan
- Subjects
0301 basic medicine ,Stereochemistry ,Naphthalenes ,Equilibrative nucleoside transporter 2 ,Equilibrative nucleoside transporter 1 ,Piperazines ,Equilibrative Nucleoside Transporter 1 ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,medicine ,Humans ,Equilibrative-Nucleoside Transporter 2 ,Uridine transport ,Pharmacology ,biology ,Adenosine transport ,Triazines ,Biological Transport ,Equilibrative nucleoside transporter ,Adenosine ,Uridine ,Kinetics ,030104 developmental biology ,Gene Expression Regulation ,chemistry ,Biochemistry ,030220 oncology & carcinogenesis ,biology.protein ,Nucleoside ,medicine.drug - Abstract
Equilibrative nucleoside transporters (ENTs) play a crucial role in the transport of nucleoside and nucleoside analogues, which are important for nucleotide synthesis and chemotherapy. In addition, ENTs regulate extracellular adenosine levels in the vicinity of its receptors and hence influence adenosine-related functions. The clinical applications of ENT inhibitors in the treatment of cardiovascular diseases and cancer therapy have been explored in numerous studies. However, all ENT inhibitors to date are selective for ENT1 but not ENT2. In the present study, we investigated the novel compound 4-((4-(2-fluorophenyl)piperazin-1-yl)methyl)-6-imino-N-(naphthalen-2-yl)-1,3,5-triazin-2-amine (FPMINT) as an inhibitor of ENT1 and ENT2. Nucleoside transporter-deficient PK15NTD cells stably expressing ENT1 and ENT2 showed that FPMINT inhibited [3H]uridine and [3H]adenosine transport through both ENT1 and ENT2 in a concentration-dependent manner. The IC50 value of FPMINT for ENT2 was 5-10-fold less than for ENT1, and FPMINT could not be displaced with excess washing. Kinetic studies revealed that FPMINT reduced Vmax of [3H]uridine transport in ENT1 and ENT2 without affecting KM. Therefore, we conclude that FPMINT inhibits ENTs in an irreversible and non-competitive manner. Although already selective for ENT2 over ENT1, further modification of the chemical structure of FPMINT may lead to even better ENT2-selective inhibitors of potential clinical, physiological and pharmacological importance.
- Published
- 2016
21. A Study on the Preparation of Epoxy - Modified Polyurethane Foam and its Adhesive Properties
- Author
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Hong Jing Wan, Zhi Hong Du, Jian Jiang Wang, Guo Shun Wan, Hong Jun Huang, Hui Zhong, and Shui Yun Ren
- Subjects
chemistry.chemical_classification ,Materials science ,Scanning electron microscope ,020209 energy ,Mechanical Engineering ,02 engineering and technology ,Polymer ,Epoxy ,Condensed Matter Physics ,Expansion ratio ,chemistry.chemical_compound ,chemistry ,Mechanics of Materials ,visual_art ,0202 electrical engineering, electronic engineering, information engineering ,visual_art.visual_art_medium ,General Materials Science ,Thermal stability ,Adhesive ,Composite material ,Prepolymer ,Polyurethane - Abstract
Epoxy resin (EP) modified polyurethane prepolymer (PUP) was prepared by synthesizing prepolymer method, and then EP/PU interpenetrating polymer networks (IPN) composites was produced with better adhesive properties as the foam expands further. The effects of the process on graft reaction and spatial structure of EP/PU IPN composites was studied by FT-IR and scanning electron microscopy (SEM). And a study on the adhesive properties of polyurethane foams with different content of epoxy resins was done by adhesion strength test. The adhesive strength of the IPNs composites were significantly improved when the EP content was 50%. The thermal stability and the expansion ratio of EP/PU IPNs composites were reduced slightly. The modified IPN composites were expected to be used as the preparation of high viscosity and high dilatability of the special - purpose materials in future.
- Published
- 2016
22. Four Hapten Spacer Sites Modulating Class Specificity: Nondirectional Multianalyte Immunoassay for 31 β-Agonists and Analogues
- Author
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Yuanming Sun, Shun Wan Chan, Jiang Wenmeng, Zhen-Lin Xu, Lanteng Wang, Sergei A. Eremin, Lingwen Zeng, Xiangmei Li, Hongtao Lei, Xing Shen, and Xin-an Huang
- Subjects
Steric effects ,Models, Molecular ,Quantitative structure–activity relationship ,biology ,medicine.diagnostic_test ,Molecular Structure ,010405 organic chemistry ,Chemistry ,010401 analytical chemistry ,Enzyme-Linked Immunosorbent Assay ,Adrenergic beta-Agonists ,01 natural sciences ,0104 chemical sciences ,Analytical Chemistry ,Antigen-Antibody Reactions ,Biochemistry ,Immunoassay ,Chemical specificity ,biology.protein ,medicine ,Screening surveillance ,Antibody ,Chirality (chemistry) ,Hapten ,Haptens - Abstract
Immunoassay methods are important for monitoring β-agonists illegally used for reducing animal fat deposition in livestock. However, there is no simultaneous screening surveillance immunoassay for detecting various β-agonist chemicals that are possibly present in food. In this study, through the use of an R-(-)-salbutamol derivative as the immunizing hapten, an antibody recognizing 31 β-agonists and analogues was generated for the first time. Three-dimensional quantitative structure-activity relationship (3D QSAR) revealed that strong steric and hydrophobic fields around the hapten spacer near C-2, as well as a chirality at C-1', dominantly modulated the class specificity of the raised antibody. However, a hapten spacer linked at C-2' or C-1 would lead to a narrow specificity, and the spacer charge at C-6 could affect the raised antibody specificity spectrum. A class specificity competitive indirect enzyme-linked immunosorbent assay (ciELISA) was established with an ideal recovery ranging from 81.8 to 118.3% based on the obtained antibody. With a good agreement to the HPLC/MS method, the proposed ciELISA was confirmed to be reliable for the rapid surveillance screening assay of β-agonists in urine. This investigation will contribute to the rational design and control of the immunoassay specificity.
- Published
- 2018
23. A New Class of Safe, Potent, and Specific P-gp Modulator: Flavonoid Dimer FD18 Reverses P-gp-Mediated Multidrug Resistance in Human Breast Xenograft in Vivo
- Author
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Yunzhe Zhao, Man Chun Law, Tsz Cheung Chong, Kin-Fai Chan, Larry M.C. Chow, Shun Wan Chan, Tak Hang Chan, Jason W. Y. Kan, Clare S. W. Yan, and Iris L. K. Wong
- Subjects
Daunorubicin ,Blotting, Western ,Pharmaceutical Science ,Antineoplastic Agents ,Breast Neoplasms ,Pharmacology ,Rhodamine 123 ,Mice ,chemistry.chemical_compound ,Pharmacokinetics ,In vivo ,Cell Line, Tumor ,Drug Discovery ,medicine ,Animals ,Humans ,Doxorubicin ,ATP Binding Cassette Transporter, Subfamily B, Member 1 ,Flavonoids ,Mice, Inbred BALB C ,business.industry ,Flavones ,Drug Resistance, Multiple ,Vinblastine ,Paclitaxel ,chemistry ,Drug Resistance, Neoplasm ,Toxicity ,Molecular Medicine ,Female ,business ,Neoplasm Transplantation ,medicine.drug - Abstract
Flavonoid dimer FD18 is a new class of dimeric P-gp modulator that can reverse cancer drug resistance. FD18 is a potent (EC50 = 148 nM for paclitaxel), safe (selective index = 574), and selective P-glycoprotein (P-gp) modulator. FD18 can modulate multidrug resistance toward paclitaxel, vinblastine, vincristine, doxorubicin, daunorubicin, and mitoxantrone in human breast cancer LCC6MDR in vitro. FD18 (1 μM) can revert chemosensitivity of LCC6MDR back to parental LCC6 level. FD18 was 11- to 46-fold more potent than verapamil. FD18 (1 μM) can increase accumulation of doxorubicin by 2.7-fold, daunorubicin (2.1-fold), and rhodamine 123 (5.2-fold) in LCC6MDR. FD18 inhibited P-gp-mediated doxorubicin efflux and has no effect on influx. FD18 at 1 μM did not affect the protein expression level of P-gp. Pharmacokinetics studies indicated that intraperitoneal administration of 45 mg/kg FD18 was enough to maintain a plasma level above EC50 (148 nM) for more than 600 min. Toxicity studies with FD18 (90 mg/kg, i.p. for 12 times in 22 days) with paclitaxel (12 mg/kg, i.v. for 12 times in 22 days) revealed no obvious toxicity or death in mice. In vivo efficacy studies indicated that FD18 (45 mg/kg, i.p. for 12 times in 22 days) together with paclitaxel (12 mg/kg, i.v. for 12 times in 22 days) resulted in a 46% reduction in LCC6MDR xenograft volume (n = 11; 648 ± 84 mm(3)) compared to paclitaxel control (n = 8; 1201 ± 118 mm(3)). There were no animal deaths or significant drop in body weight and vital organ wet weight. FD18 can increase paclitaxel accumulation in LCC6MDR xenograft by 1.8- to 2.2-fold. The present study suggests that FD18 represents a new class of safe and potent P-gp modulator in vivo.
- Published
- 2015
24. Chemical properties and bioactivities of Goji (Lycium barbarum) polysaccharides extracted by different methods
- Author
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Shun Wan Chan, Chao Zhao, Jianyong Wu, Xia Chen, and Ri Fu Yang
- Subjects
Antioxidant ,DPPH ,medicine.medical_treatment ,Trolox equivalent antioxidant capacity ,Medicine (miscellaneous) ,Immunomodulation ,Subcritical water extraction ,chemistry.chemical_compound ,Antioxidant activity ,Functional food ,Polysaccharides ,Ultrasound ,medicine ,TX341-641 ,Ethanol precipitation ,Nutrition and Dietetics ,Traditional medicine ,biology ,Nutrition. Foods and food supply ,Extraction (chemistry) ,Water extraction ,biology.organism_classification ,Lycium barbarum ,chemistry ,Lycium ,Food Science - Abstract
Lycium barbarum fruit (Goji or wolfberry) is widely used as a functional food as well as an herb in Chinese medicine. The polysaccharides of L. barbarum (LBPs) are well-known for immunomodulation and antioxidant activities. This study evaluated the yields, properties and bioactivities of LBPs extracted from L. barbarum fruit by different methods including hot water (HWE 100 °C), ultrasonic water (UWE 30–40 °C), subcritical water (SWE 110 °C), and ultrasound-enhanced subcritical water extraction (USWE 110 °C). The total LBP yield (80 min extraction followed by ethanol precipitation) was the highest from USWE (14% w/w) and the lowest from HWE (7.6%). The LBP from USWE also showed the highest protein (27.9%) and phenolic content (5.3%, w/w), and the highest antioxidant activities (scavenging radicals by DPPH and trolox equivalent antioxidant capacity assays; ferric reducing power). It also showed the highest immunoactivities in activating the phagocytosis and NO production of RAW264.7 macrophages. USWE was proven the most efficient method for extraction of LBPs. Temperature and ultrasound were two chief factors affecting the extraction yield, chemical properties and bioactivities of LBP.
- Published
- 2015
25. Basal Flt1 tyrosine kinase activity is a positive regulator of endothelial survival and vascularization during zebrafish embryogenesis
- Author
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Shang Li, Maggie Pui Man Hoi, Yiu Wa Kwan, Shun Wan Chan, Simon Ming-Yuen Lee, Yuan Ye Dang, Xuelin Zhou, and George P.H. Leung
- Subjects
Embryo, Nonmammalian ,Cell Survival ,Angiogenesis ,Biophysics ,Embryonic Development ,Neovascularization, Physiologic ,Biology ,Biochemistry ,Wortmannin ,Phosphatidylinositol 3-Kinases ,chemistry.chemical_compound ,Human Umbilical Vein Endothelial Cells ,Animals ,Humans ,Protein Kinase Inhibitors ,Molecular Biology ,Zebrafish ,Phosphoinositide-3 Kinase Inhibitors ,Vascular Endothelial Growth Factor Receptor-1 ,Kinase ,Zebrafish Proteins ,biology.organism_classification ,Isoflavones ,Molecular biology ,Androstadienes ,Endothelial stem cell ,Calycosin ,chemistry ,embryonic structures ,cardiovascular system ,Phosphorylation ,Endothelium, Vascular ,Proto-Oncogene Proteins c-akt ,Tyrosine kinase ,Signal Transduction - Abstract
Background The role of Kdr (VEGFR-2/Flk-1) in vascular formation has been well described, but the role of Flt1 (VEGFR-1) is not well studied and is generally considered as a decoy receptor for trapping VEGF. Methods The effects of VEGFR1/2 kinase inhibitor (VRI) and calycosin on Flt1 tyrosine kinase (TK) activity were evaluated by molecular docking, enzymatic inhibition assay, protein co-immunoprecipitation and siRNA gene knock-down analysis in HUVECs. Toxicities of the chemicals were examined using HUVECs viability. Their effects on angiogenesis and vessel formation were furthered studied in HUVECs in vitro and Tg ( fli-1 : EGFP ) zebrafish in vivo . The gene and protein expression of VEGF and VEGF receptors were investigated by quantitative RT-PCR and Western blot. Results VRI strongly inhibited physiological functions of both VEGF receptors and suppressed endothelial cell survival. This resulted in blood vessel loss in zebrafish embryos. Interestingly, calycosin co-treatment impeded VRI-induced blood vessel loss. Docking and kinase inhibition assay revealed that calycosin competed with VRI for the tyrosine kinase domain of Flt1 without affecting ATP binding. On the contrary, calycosin did not affect the interaction between VRI and Kdr-TK. Consistent with these results, calycosin counteracted the inhibition of Flt1-TK and PI3K phosphorylation induced by VRI in HUVECs. Further studies in vitro and in vivo showed that the minimizing effect of calycosin on VRI-mediated endothelial cytotoxicity was blocked by wortmannin (a PI3K inhibitor). The impeding effect of calycosin on VRI-induced blood vessel loss was absent in zebrafish embryos injected with Flt1 MO. Conclusions Flt1-tyrosine kinase (TK) activity contributed significantly in endothelial cells survival and vascular development during embryo angiogenesis in zebrafish by engaging PI3K/Akt pathway. General significance The roles of Flt1 activity in endothelial cell survival in physiological vascular formation may have been previously under-appreciated.
- Published
- 2015
26. Identification of disulfide isomerase ERp57 as a target for small molecule cardioprotective agents
- Author
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Luchen Shan, Guohui Li, Yuqiang Wang, Guozhen Cui Cui, Simon Ming-Yuen Lee, Shun Wan Chan, Ivan K. Chu, Yiu Wa Kwan, Maggie Pui Man Hoi, and George P.H. Leung
- Subjects
medicine.diagnostic_test ,biology ,Chemistry ,General Chemical Engineering ,Insulin ,medicine.medical_treatment ,Active site ,General Chemistry ,Oxidative phosphorylation ,Small molecule ,Biochemistry ,Western blot ,medicine ,biology.protein ,Cardioprotective Agent ,Protein disulfide-isomerase ,Molecular probe - Abstract
We previously reported a novel danshensu analogue known as ADTM, which exhibited strong protective effects against oxidative stress-induced cellular injury and acute ischemic myocardial infarct in rat; however, the exact protein target of ADTM has not been fully characterized. In the present study, a biotin-conjugated ADTM analogue (BAA) was employed as molecular probe to identify its protein targets. BAA exhibited similar protective effect against oxidative stress-induced cell injury in H9c2 cardiomyoblast. A chemical proteomic approach identified ERp57 as the specific target for BAA. Further evaluation with Western blot and immunofluorescence staining assays confirmed the direct interactions between BAA and ERp57. Moreover, BAA displayed potent inhibitory effect on the catalytic activity of ERp57 in the insulin reduction assay. Molecular docking showed that BAA bound at the active site of ERp57. These data suggested that ERp57 is a potential target of cardioprotective danshensu analogues, and provided the basis for the further optimization of the cardioprotective compounds.
- Published
- 2015
27. A stable fluorinated and alkylated lithium malonatoborate salt for lithium ion battery application
- Author
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Sheng Dai, Shun Wan, Xueguang Jiang, Bingkun Guo, Xiao-Guang Sun, and John B. Goodenough
- Subjects
chemistry.chemical_classification ,Lithium vanadium phosphate battery ,Inorganic chemistry ,Metals and Alloys ,Salt (chemistry) ,chemistry.chemical_element ,General Chemistry ,Electrolyte ,Catalysis ,Lithium-ion battery ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,chemistry.chemical_compound ,chemistry ,Materials Chemistry ,Ceramics and Composites ,Lithium ,Graphite ,Boron ,Ethylene carbonate ,Nuclear chemistry - Abstract
A new fluorinated and alkylated lithium malonatoborate salt, lithium bis(2-methyl-2-fluoromalonato)borate (LiBMFMB), has been synthesized for lithium ion battery application. A 0.8 M LiBMFMB solution is obtained in a mixture of ethylene carbonate (EC) and ethyl methyl carbonate (EMC) (1 : 2 by wt). The new LiBMFMB based electrolyte exhibits good cycling stability and rate capability in LiNi0.5Mn1.5O4 and graphite based half-cells.
- Published
- 2015
28. Sodium Sulfate Separation from Aqueous Alkaline Solutions via Crystalline Urea-Functionalized Capsules: Thermodynamics and Kinetics of Crystallization
- Author
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Arbin Rajbanshi, Radu Custelcean, Frederick {Fred} Sloop Jr, Shun Wan, and Bruce A. Moyer
- Subjects
Aqueous solution ,Kinetics ,Inorganic chemistry ,Thermodynamics ,General Chemistry ,Condensed Matter Physics ,law.invention ,chemistry.chemical_compound ,Reaction rate constant ,chemistry ,law ,Crystallization adjutant ,Sodium sulfate ,General Materials Science ,Crystallization ,Sulfate ,Dissolution - Abstract
The thermodynamics and kinetics of crystallization of sodium sulfate with a tripodal tris-urea receptor (L1) from aqueous alkaline solutions have been measured in the 15–55 °C temperature range for a fundamental understanding of the elementary steps involved in this sulfate separation method. The use of radiolabeled Na235SO4 provided a practical way to monitor the sulfate concentration in solution by β liquid scintillation counting. Our results are consistent with a two-step crystallization mechanism, involving relatively quick dissolution of crystalline L1 followed by the rate-limiting crystallization of the Na2SO4(L1)2(H2O)4 capsules. We found that temperature exerted relatively little influence over the equilibrium sulfate concentration, which ranged between 0.004 and 0.011 M. This corresponds to 77–91% removal of sulfate from a solution containing 0.0475 M initial sulfate concentration, as found in a typical Hanford waste tank. The apparent pseudo-first-order rate constant for sulfate removal increase...
- Published
- 2014
29. Resveratrol and cardiovascular health – Promising therapeutic or hopeless illusion?
- Author
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Philip Chiu Tsun Tang, Shun Wan Chan, Susan Ho, Yam Fung Ng, and Michael Gyda
- Subjects
Pharmacology ,business.industry ,Cardiovascular health ,food and beverages ,Context (language use) ,Disease ,Resveratrol ,Bioinformatics ,Research findings ,chemistry.chemical_compound ,chemistry ,Biochemistry ,Active compound ,Medicine ,business ,POLYGONUM CUSPIDATUM - Abstract
Resveratrol (3,5,4'-trihydroxy-trans-stilbene) is a natural polyphenolic compound that exists in Polygonum cuspidatum, grapes, peanuts and berries, as well as their manufactured products, especially red wine. Resveratrol is a pharmacologically active compound that interacts with multiple targets in a variety of cardiovascular disease models to exert protective effects or induce a reduction in cardiovascular risks parameters. This review attempts to primarily serve to summarize the current research findings regarding the putative cardioprotective effects of resveratrol and the molecular pathways underlying these effects. One intent is to hopefully provide a relatively comprehensive resource for clues that may prompt ideas for additional mechanistic studies which might further elucidate and strengthen the role of the stilbene family of compounds in cardiovascular disease and cardioprotection. Model systems that incorporate a significant functional association with tissues outside of the cardiovascular system proper, such as adipose (cell culture, obesity models) and pancreatic (diabetes) tissues, were reviewed, and the molecular pathways and/or targets related to these models and influenced by resveratrol are discussed. Because the body of work encompassing the stilbenes and other phytochemicals in the context of longevity and the ability to presumably mitigate a plethora of afflictions is replete with conflicting information and controversy, especially so with respect to the human response, we tried to remain as neutral as possible in compiling and presenting the more current data with minimal commentary, permitting the reader free reign to extract the knowledge most helpful to their own investigations.
- Published
- 2014
30. Chemical Analysis of Astragali Complanati Semen and Its Hypocholesterolemic Effect Using Serum Metabolomics Based on Gas Chromatography-Mass Spectrometry
- Author
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Huan Zhang, Jian Hong Wu, Tung-Ting Sham, Songyun Tang, Shun Wan Chan, Chi-On Chan, and Daniel K. W. Mok
- Subjects
0301 basic medicine ,Normal diet ,Physiology ,Electrospray ionization ,Clinical Biochemistry ,Orbitrap ,01 natural sciences ,Biochemistry ,Article ,law.invention ,03 medical and health sciences ,chemistry.chemical_compound ,Metabolomics ,law ,Astragali Complanati Semen ,serum metabolomics ,hypercholesterolemia ,mass spectrometry ,Molecular Biology ,chemistry.chemical_classification ,Chromatography ,010401 analytical chemistry ,lcsh:RM1-950 ,Fatty acid ,Cell Biology ,0104 chemical sciences ,030104 developmental biology ,lcsh:Therapeutics. Pharmacology ,chemistry ,Arachidonic acid ,Docosapentaenoic acid ,Gas chromatography–mass spectrometry - Abstract
The hypocholesterolemic protective effect of the dried seed of Astragalus complanatus (ACS) was investigated in rats fed with normal diet, high cholesterol diet (HCD), and HCD plus 70% ethanol extract of ACS (600 mg/kg/day) by oral gavage for four weeks. ACS extract was tested to be rich in antioxidants, which may be contributed to its high content of phenolic compounds. Consumption of ACS remarkably suppressed the elevated total cholesterol (p < 0.01) and LDL-C (p < 0.001) induced by HCD. Chemical constituents of ACS extract were analyzed by ultra-performance liquid chromatography coupled with electrospray ionization orbitrap mass spectrometry and the results showed that the ACS extract mainly consisted of phenolic compounds including flavonoids and flavonoid glycosides. In addition, based on the serum fatty acid profiles, elucidated using gas chromatography-mass spectrometry, free and esterified fatty acids including docosapentaenoic acid, adrenic acid, dihomo-γ-linolenic acid and arachidonic acid were regulated in ACS treatment group. Western blot results further indicated the protein expression of peroxisome proliferator-activated receptor alpha (PPARα) (p < 0.05) in liver was upregulated in ACS treatment group. To conclude, our results clearly demonstrated that ACS provides beneficial effect on lowering HCD associated detrimental change.
- Published
- 2017
31. Evaluation in zebrafish model of the toxicity of rhodamine B-conjugated crotamine, a peptide potentially useful for diagnostics and therapeutics
- Author
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Shun Wan Chan, Yiu Wa Kwan, Judy Yuet-Wa Chan, Gandhi Rádis-Baptista, Simon Ming-Yuen Lee, and Hefeng Zhou
- Subjects
0301 basic medicine ,animal structures ,Embryo, Nonmammalian ,Health, Toxicology and Mutagenesis ,RHOB ,Venom ,Peptide ,Biology ,Pharmacology ,Toxicology ,Biochemistry ,Animals, Genetically Modified ,03 medical and health sciences ,Crotalid Venoms ,Toxicity Tests ,medicine ,Animals ,Tissue Distribution ,Yolk sac ,Molecular Biology ,Zebrafish ,Fluorescent Dyes ,chemistry.chemical_classification ,Rhodamines ,fungi ,Heart ,General Medicine ,biology.organism_classification ,Acute toxicity ,Crotamine ,030104 developmental biology ,medicine.anatomical_structure ,chemistry ,Larva ,embryonic structures ,Toxicity ,Molecular Medicine ,Locomotion - Abstract
Crotamine is defensin-like cationic peptide from rattlesnake venom that possesses anticancer, antimicrobial, and antifungal properties. Despite these promising biological activities, toxicity is a major concern associated with the development of venom-derived peptides as therapeutic agents. In the present study, we used zebrafish as a system model to evaluate the toxicity of rhodamine B-conjugated (RhoB) crotamine derivative. The lethal toxic concentration of RhoB-crotamine was as low as 4 μM, which effectively kill zebrafish larvae in less than 10 min. With non-lethal concentrations (
- Published
- 2017
32. Production of polyhydroxyalkanoates (PHA) using sludge from different wastewater treatment processes and the potential for medical and pharmaceutical applications
- Author
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Shun Wan Chan, Peter Hoi-fu Yu, Pui Ling Chan, Yiu Fai Tsang, Yujie Wang, Hong Chua, and Wai Lam
- Subjects
0106 biological sciences ,0301 basic medicine ,Denitrification ,Bacillus cereus ,Sequencing batch reactor ,01 natural sciences ,Waste Disposal, Fluid ,Polyhydroxyalkanoates ,Microbiology ,03 medical and health sciences ,Yersinia frederiksenii ,Bioreactors ,Drug Delivery Systems ,010608 biotechnology ,Bioreactor ,Environmental Chemistry ,Waste Management and Disposal ,Water Science and Technology ,Pyrenes ,biology ,Bacteria ,Sewage ,Tissue Engineering ,Chemistry ,Bacillus pumilus ,fungi ,General Medicine ,biology.organism_classification ,Pseudomonas putida ,Drug Liberation ,030104 developmental biology ,Nanoparticles - Abstract
In this study, seven strains of bacteria with polyhydroxyalkanoates (PHA)-producing ability (i.e. Bacillus cereus, Pseudomonas putida, Bacillus pumilus, Pseudomona huttiensis, Yersinia frederiksenii, Aeromonas ichthiosmia, and Sphingopyxis terrae) were isolated from various waste treatment plants in Hong Kong. Simultaneous wastewater treatment and PHA accumulation were successfully achieved in the bioreactors using isolated bacteria from different sludges. At the organic loading less than 13,000 ppm, more than 95% of chemical oxygen demand (COD) was removed by the isolated strains before the decrease of PHA accumulation. In addition, more than 95% of nitrogen removal was achieved by all isolated strains. In the bioreactors inoculated with single strains, the highest yields of poly(3-hydroxybutyrate) (PHB) and poly(3-hydroxyvalerate) (PHV) were obtained in A. ichthiosmia (84 mg PHB/g) and B. cereus (69 mg/g), respectively. For the mixed culture, the highest yields of PHB and PHV were increased by 55% and 45% in the system inoculated with B. pumilus and A. ichthiosmia. The biologically synthesized PHA also showed the potential applications in drug delivery and tissue engineering. PHA-nanoparticles loaded with pyrene were successfully prepared by recombinant Escherichia coli. The results of in vitro drug release and biocompatibility tests revealed that nanoparticles could be used as safer dray carriers with high loading capacity and efficiency. After 20 days, the cells successfully grew on 90% of the PHA-aortic valve.
- Published
- 2017
33. Cardiovascular Protective Effects of Salvianic Acid A on db/db Mice with Elevated Homocysteine Level
- Author
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Christopher Lai, Shun Wan Chan, Lei Gao, and Parco M. Siu
- Subjects
0301 basic medicine ,Aging ,medicine.medical_specialty ,Hyperhomocysteinemia ,Homocysteine ,Article Subject ,030204 cardiovascular system & hematology ,Left ventricular hypertrophy ,medicine.disease_cause ,Biochemistry ,03 medical and health sciences ,chemistry.chemical_compound ,Mice ,0302 clinical medicine ,Internal medicine ,Hcy metabolism ,medicine ,Animals ,Endothelial dysfunction ,lcsh:QH573-671 ,Chemistry ,lcsh:Cytology ,Cell Biology ,General Medicine ,Methylation ,medicine.disease ,Redox status ,030104 developmental biology ,Endocrinology ,Cardiovascular Diseases ,Echocardiography ,Lactates ,Female ,Oxidative stress ,Research Article - Abstract
The onsets of left ventricular hypertrophy (LVH) and endothelial dysfunction (ED) in diabetics, especially in those with elevated homocysteine (Hcy), precede the development of cardiovascular (CV) events. Salvianic acid A (SAA) is a renowned Traditional Chinese Medicine (TCM) that has been applied in the treatment of cardiovascular disease for many decades. In this study, we aimed (1) to investigate the CV protective effects of SAA on ameliorating LVH and ED in db/db mice with elevated blood Hcy level and (2) to decipher whether the observed CV protective effects of SAA are associated with Hcy metabolism by modulating the methylation potential and redox status in the liver of the db/db mice with elevated blood Hcy level. Our results found that the administration of SAA could significantly slow down the build-up of left ventricular mass and ameliorate ED. Immunological assay analysis on the mouse liver tissue also indicated that SAA treatment on db/db mice with elevated Hcy was associated with reduced methylation potential but improved redox status. In conclusion, we revealed that SAA has the potential to protect against the hyperglycemia- and hyperhomocysteinemia-induced oxidative stress on diabetic mice via modulation in Hcy metabolism.
- Published
- 2017
34. Uptake and Protective Effects of Ergothioneine in Human Endothelial Cells
- Author
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Albert S.M. Sit, Marvin Hausman, G Leung, Maggie Pm Hoi, Cui Yang, Yiu Wa Kwan, Rachel Ws Li, Paul M. Vanhoutte, Simon My Lee, and Shun Wan Chan
- Subjects
Male ,Antioxidant ,Cell Survival ,medicine.medical_treatment ,Glutathione reductase ,medicine.disease_cause ,Antioxidants ,Rats, Sprague-Dawley ,Superoxide dismutase ,chemistry.chemical_compound ,medicine ,Animals ,Humans ,Xanthine oxidase ,Cells, Cultured ,Pharmacology ,chemistry.chemical_classification ,Reactive oxygen species ,biology ,Endothelial Cells ,Ergothioneine ,Xanthine ,Rats ,Oxidative Stress ,chemistry ,Biochemistry ,Cytoprotection ,biology.protein ,Molecular Medicine ,Reactive Oxygen Species ,Oxidative stress - Abstract
Ergothioneine is a thiourea derivative of histidine found in food, especially mushrooms. Experiments in cell-free systems and chemical assays identified this compound as a powerful antioxidant. Experiments were designed to test the ability of endothelial cells to take up ergothioneine and hence benefit from protection against oxidative stress. Reverse-transcription polymerase chain reaction and Western blotting demonstrated transcription and translation of an ergothioneine transporter in human brain microvascular endothelial cells (HBMECs). Uptake of [(3)H]ergothioneine occurred by the organic cation transporter novel type-1 (OCTN-1), was sodium-dependent, and was reduced when expression of OCTN-1 was silenced by small interfering RNA (siRNA). The effect of ergothioneine on the production of reactive oxygen species (ROS) in HBMECs was measured using dichlorodihydrofluorescein and lucigenin, and the effect on cell viability was studied using the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay. ROS production and cell death induced by pyrogallol, xanthine oxidase plus xanthine, and high glucose were suppressed by ergothioneine. The antioxidant and cytoprotective effects of ergothioneine were abolished when OCTN-1 was silenced using siRNA. The expression of NADPH oxidase 1 was decreased, and those of glutathione reductase, catalase, and superoxide dismutase enhanced by the compound. In isolated rat basilar arteries, ergothioneine attenuated the reduction in acetylcholine-induced relaxation caused by pyrogallol, xanthine oxidase plus xanthine, or incubation in high glucose. Chronic treatment with the compound improved the response to acetylcholine in arteries of rats with streptozotocin-induced diabetes. In summary, ergothioneine is taken up by endothelial cells via OCTN-1, where the compound then protects against oxidative stress, curtailing endothelial dysfunction.
- Published
- 2014
35. A Review of the Pharmacological Effects of Piceatannol on Cardiovascular Diseases
- Author
-
Shun Wan Chan and Yee Ling Tang
- Subjects
Pharmacology ,Piceatannol ,chemistry.chemical_compound ,chemistry ,business.industry ,Medicine ,Resveratrol ,business ,Social burden - Abstract
The incidence of cardiovascular diseases (CVDs) is high in both developed and developing countries. It has a high global rate of mortality and causes heavy social burden. Drugs are available for managing or treating CVDs and its complications. Consumption of dietary supplements or functional foods for reducing the risk of CVDs has also gained wide recognition by the general public. Piceatannol, an analog and metabolite of resveratrol, is a natural stilbene commonly found in the skin of grapes and wine. Piceatannol is believed to be a potent compound with certain cardiovascular therapeutic effects, such as the prevention of hypercholesterolemia, arrhythmia, atherosclerosis, and angiogenesis. It also has vasorelaxation and antioxidant activities. A comprehensive review of piceatannol concludes that piceatannol has the potential to be developed into health products for the cardiovascular system to help modern society reduce the high CVD incidence. However, further investigations are warranted in order to increase the bioavailability and understand the biological mechanisms and safety of using piceatannol.
- Published
- 2014
36. Mesoporous graphene-like carbon sheet: high-power supercapacitor and outstanding catalyst support
- Author
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Pengfei Zhang, Zhen-An Qiao, Sheng Dai, Shun Wan, and Zhiyong Zhang
- Subjects
Pyromellitic dianhydride ,Materials science ,Renewable Energy, Sustainability and the Environment ,Graphene ,Catalyst support ,Inorganic chemistry ,chemistry.chemical_element ,General Chemistry ,law.invention ,chemistry.chemical_compound ,chemistry ,law ,Carbide-derived carbon ,General Materials Science ,Mesoporous material ,Carbon ,Polyimide ,Nanosheet - Abstract
Nowadays, continuous scientific endeavors are being directed toward low-cost, mild, scalable and reliable synthesis of graphene-based materials, in order to advance various graphene-related applications. So far, specific surface areas of current bulk graphene powders or graphene-like nanosheets are much lower than the theoretical value (2630 m2 g−1) of individual graphene, remaining a challenge for carbon chemists. Herein, mesoporous graphene-like carbon sheets with high specific surface area (up to 2607 m2 g−1) and high pore volume (up to 3.12 cm3 g−1) were synthesized by using polyimide chemistry in the molten salt “solvent.” In this process, abundant pyromellitic dianhydride and aromatic diamine undergo polycondensation together with further carbonization in molten KCl–ZnCl2, in which in situ formed linear aromatic polyimide with a sp2 hybridized carbon skeleton could be directly coupled and rearranged into a two-dimensional graphene-like nanosheet around the “salt scaffold”. Carbon nanosheets with well-defined mesopores (∼3.5 nm) could be easily obtained by washing salt melts in water, while the salts could be recovered and reused for the subsequent reaction. The nitrogen atoms in amine also afforded the resulting carbon with uniform foreign atoms (nitrogen content = ∼6%). Moreover, holey carbon sheets with well-dispersed and through-plane nanoholes (diameter: 5–10 nm) could be constructed by using different monomers. Being a potential electrode material in supercapacitors, the as-made carbon nanosheet possessed a significant specific capacitance (131.4–275.5 F g−1) even at a scan rate of 2000 mV s−1. Additionally, powerful nanohybrids of carbon sheet–Co3O4 were also prepared with good performance in the aerobic oxidation of alcohols and amines to aldehydes and imines, respectively.
- Published
- 2014
37. Oxidation Behavior of Filled Skutterudite CeFe4Sb12 in Air
- Author
-
Pengfei Qiu, Xiangyang Huang, Shun Wan, Yuting Qiu, Xiaoya Li, Lidong Chen, and Xugui Xia
- Subjects
Materials science ,Solid-state physics ,Scanning electron microscope ,Oxide ,Mineralogy ,chemistry.chemical_element ,Activation energy ,engineering.material ,Condensed Matter Physics ,Decomposition ,Oxygen ,Electronic, Optical and Magnetic Materials ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,Thermoelectric effect ,Materials Chemistry ,engineering ,Skutterudite ,Electrical and Electronic Engineering - Abstract
The oxidation behavior of CeFe4Sb12 compound in air was studied in this work. x-Ray diffractometry, scanning electron microscopy observation, and activation energy calculation suggest that CeFe4Sb12 is very easily oxidized at elevated temperature. The reason for the weak resistance to oxidation is mainly due to the unstable “FeSb3” structure and the high Ce filling fraction in the skutterudite voids. At elevated temperature, Ce fillers which have high oxygen affinity firstly react with oxygen. This process proceeds accompanied by decomposition of “Fe4Sb12” into FeSb2 and Sb, which in turn accelerates the oxidation rate. The Ce fillers in CeFe4Sb12 provide a short path for rapid interdiffusion of oxygen, which leads to fast growth of the oxide layer, with thickness of about 200 μm at 900 K after only 1 h exposure in air. This result suggests that appropriate protection from oxidation is necessary for real applications of CeFe4Sb12.
- Published
- 2013
38. High-temperature thermoelectric properties of layered Ba CoO2
- Author
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Yang Danfeng, Xiangyang Huang, Xu Guisheng, Jinfeng Liu, and Shun Wan
- Subjects
Materials science ,Ion exchange ,Mechanical Engineering ,Metals and Alloys ,Analytical chemistry ,chemistry.chemical_element ,Mineralogy ,Barium ,Condensed Matter Physics ,Thermoelectric materials ,Cobaltite ,chemistry.chemical_compound ,Thermal conductivity ,chemistry ,Mechanics of Materials ,Seebeck coefficient ,Thermoelectric effect ,General Materials Science ,Crystallite - Abstract
Polycrystalline samples of Ba x CoO 2 ( x = 0.19, 0.28, 0.30, 0.33) were prepared by an ion-exchange technique. The high-temperature thermoelectric properties were measured for the first time. The electrical and thermal conductivity of Ba x CoO 2 decrease with decreasing the barium content from 0.33 to 0.19, while the Seebeck coefficient is not sensitive to the barium content. The maximum ZT value is 0.21 for Ba 0.19 CoO 2 at 800 K. The results suggest that Ba x CoO 2 might be another possible candidate for thermoelectric oxide materials.
- Published
- 2015
39. Advancing polymers of intrinsic microporosity by mechanochemistry
- Author
-
Pengfei Zhang, Sheng Dai, Xueguang Jiang, and Shun Wan
- Subjects
chemistry.chemical_classification ,Materials science ,High molecular mass ,chemistry ,Renewable Energy, Sustainability and the Environment ,Mechanochemistry ,Dispersity ,General Materials Science ,Nanotechnology ,General Chemistry ,Polymer ,Continuous exposure ,Grinding - Abstract
Herein, we report a fast (15 min) and solvent-free mechanochemical approach to construct polymers of intrinsic microporosity (PIMs) with high molecular mass and low polydispersity by solid grinding. The enhanced reaction efficiency results from the instantaneous frictional heating and continuous exposure of active sites within those solid reactants.
- Published
- 2015
40. Study on Adhesion Properties of Poly (sodium acrylate)-Polyvinyl Alcohol Super Absorbent Resin
- Author
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Guo Shun Wan, Lei Jiang, Zhi Hong Du, Hong Jun Huang, and Hong Jing Wan
- Subjects
chemistry.chemical_classification ,Materials science ,Absorption of water ,technology, industry, and agriculture ,Alcohol ,General Medicine ,Polymer ,Adhesion ,Polyvinyl alcohol ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,Super absorbent ,Stress relaxation ,Acrylic acid - Abstract
A poly (sodium acrylate)-polyvinyl alcohol superabsorbent resin is synthesized from acrylic acid (AA) and polyvinyl alcohol. A new method is established to measure the adhesion properties. Then the influence of different experimental conditions on the adhesion properties of the resin is discussed. The results indicate that the adhesion properties of super absorbent resin have some variation with the water absorption increased, the initial pressure and the separation rate. It can be explained by the theory of polymer structure, mechanical interlock and stress relaxation.
- Published
- 2013
41. Emodin elicits cytotoxicity in human lung adenocarcinoma A549 cells through inducing apoptosis
- Author
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De-Jian Guo, Huan Zhang, Wing-Yan Li, George P.H. Leung, Peter H. Yu, Yam-Fung Ng, Zi-Dong Guo, Shun Wan Chan, Yiu Wa Kwan, and Simon Ming-Yuen Lee
- Subjects
Emodin ,Lung Neoplasms ,Immunology ,Gene Expression ,Adenocarcinoma of Lung ,Apoptosis ,DNA Fragmentation ,Adenocarcinoma ,chemistry.chemical_compound ,Cell Line, Tumor ,Humans ,Cytotoxic T cell ,Pharmacology (medical) ,DNA Breaks, Single-Stranded ,Cytotoxicity ,Cell Proliferation ,Pharmacology ,A549 cell ,Cell Cycle Checkpoints ,Molecular biology ,chemistry ,Cell culture ,DNA fragmentation ,Growth inhibition ,Apoptosis Regulatory Proteins - Abstract
This study investigated the mechanism of the cytotoxic effect of emodin, an active anthraquinone, on human lung adenocarcinoma A549 cells. In vitro growth inhibition and suppression on colony forming were used to evaluate the effects of emodin on A549 cells. Emodin's ability in changing the expressions of apoptosis-related genes was studied by real-time RT-PCR. Emodin could significantly inhibit the growth of A549 cells with IC50 = 16.85 μg/ml (~60 μM). It also concentration dependently inhibited the colony-forming ability of A549 cells with IC50 = 7.60 μg/ml (~30 μM). Hallmarks of apoptosis, such as single-strand DNA breakage and DNA fragmentation, were observed in A549 cells treated with emodin. Emodin (72 h) treatment could up-regulate the gene expression of FASL (p < 0.05) and down-regulate the gene expression of C-MYC (p < 0.01), but induce no significant changes in the gene expressions of MCL1, GAPDH, BAX and CCND1. These results suggest that emodin could induce growth inhibition and apoptosis in A549 cells through modifying the extrinsic apoptotic pathways and the induction of cell cycle arrest.
- Published
- 2013
42. Suppression of diet-induced hypercholesterolaemia by saponins from Panax notoginseng in rats
- Author
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Jing Yi Tang, Simon Ming-Yuen Lee, Yiu Wa Kwan, Tung-Ting Sham, Jian Hong Wu, Shun Wan Chan, George P.H. Leung, Jian-Bo Wan, and Youhua Wang
- Subjects
medicine.medical_specialty ,Saponin ,Panax notoginseng ,Medicine (miscellaneous) ,Reductase ,Nitric oxide ,chemistry.chemical_compound ,Enos ,Internal medicine ,medicine ,TX341-641 ,Receptor ,Hypercholesterolaemia ,Nutrition and Dietetics ,biology ,Nutrition. Foods and food supply ,Cholesterol ,Peroxisome ,biology.organism_classification ,Vasoprotective ,Endocrinology ,chemistry ,Rat ,lipids (amino acids, peptides, and proteins) ,Food Science - Abstract
Panax notoginseng saponins (PNS) are major active constituents of P. notoginseng. This study investigated the mechanisms of the hypocholesterolaemic and atheroscleroprotective effects of PNS. It was found that treatment of PNS (30 or 100 mg/kg/day, p.o.) could significantly reduce elevated serum total cholesterol, triacylglycerol, low-density lipoprotein cholesterol and atherogenic index induced by feeding rats with high cholesterol diet for 28 days. High-density lipoprotein cholesterol could also be increased by PNS treatment. Additionally, PNS significantly enhanced the hypercholesterolaemia-induced reduction of superoxide dismutase activity in the liver. In hypercholesterolaemic rats, PNS significantly improved the endothelium-dependent vasodilatation, acetylcholine-induced nitric oxide production and endothelial nitric oxide synthase mRNA expression in a dose-dependent manner. It also significantly reversed the hypercholesterolaemia-induced changes in mRNA expressions of cholesterol 7α-hydroxylase and peroxisome proliferator-activated receptor α but not HMG-CoA reductase. The findings provided evidence for using PNS to prevent the development of hypercholesterolaemia and atherosclerosis. The hypocholesterolaemic activity of PNS is likely to be resulted from inducing the biosynthesis of bile acids from cholesterol and promoting the β-oxidation of fatty acids in the liver. The vasoprotective function of PNS may be brought about by increasing the gene expression of eNOS in endothelial cells, its antioxidative activity, or both.
- Published
- 2013
43. Cholesterol lowering and vascular protective effects of ethanolic extract of dried fruit of Crataegus pinnatifida, hawthorn (Shan Zha), in diet-induced hypercholesterolaemic rat model
- Author
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Simon Ming-Yuen Lee, Peter H. Yu, Yiu Wa Kwan, Chang Li, George P.H. Leung, Shun Wan Chan, Huan-Le Cheng, Ching-Yee Kwok, Tak-Yi Chan, Daniel K. W. Mok, and Yam-Fung Ng
- Subjects
Nutrition and Dietetics ,Dried fruit ,Normal diet ,Traditional medicine ,biology ,Cholesterol ,Hawthorn ,Nutrition. Foods and food supply ,Rat model ,Anti-atherogenic ,Medicine (miscellaneous) ,Cholesterol lowering ,Hypocholesterolaemic ,Cholesterol 7 alpha-hydroxylase ,Crataegus pinnatifida ,biology.organism_classification ,chemistry.chemical_compound ,High-density lipoprotein ,chemistry ,Biochemistry ,Vascular protection ,TX341-641 ,Food Science ,Cholersterol - Abstract
Consumption of functional foods for managing plasma cholesterol level has gained acceptance globally. The hypocholesterolaemic and vascular protective effects of the dried fruit of Crataegus pinnatifida, hawthorn (Shan Zha), were investigated in rats fed with normal diet, high cholesterol diet (HCD) or HCD plus Shan Zha 80% ethanolic extract treatment (30 or 100 mg/kg/day, p.o.) for 4 weeks. Shan Zha extract markedly reversed the increased plasma total cholesterol and high density lipoprotein cholesterol induced by HCD with a dose-dependent improvement on the atherogenic index. It also demonstrated good hepatoprotective function by reducing lipid content in the liver. The blunted endothelium-mediated aortic relaxation in HCD-fed rats was restored by high dosage of Shan Zha extract treatment. The current results showed that Shan Zha extract could provide its cholesterol lowering effect by up-regulating hepatic CYP7A1 mRNA expression which leads to enhanced bile acid biosynthesis. It is postulated that the hypocholesterolaemic effect is the primary beneficial effect given by Shan Zha extract; it then leads to other secondary beneficial effects such as vascular protective and hepatoprotective functions. Thus, Shan Zha extract could provide an overall improvement on the hepatic and vascular systems that may be important in relieving hypercholesterolaemia-related complications.
- Published
- 2013
44. Dihydrogen Phosphate Clusters: Trapping H2PO4– Tetramers and Hexamers in Urea-Functionalized Molecular Crystals
- Author
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Radu Custelcean, Arbin Rajbanshi, and Shun Wan
- Subjects
chemistry.chemical_compound ,Crystallography ,chemistry ,Hydrogen bond ,Urea ,General Materials Science ,General Chemistry ,Trapping ,Condensed Matter Physics ,Phosphate - Abstract
Co-crystallization of two urea-functionalized ligandswith tetrabutylammonium (TBA) dihydrogen phosphate resulted in the isolation of discrete (H2PO4–)4 and (H2PO4–)6 clusters stabilized in the crystalline state by multiple urea hydrogen bonds. Structural analysis by single-crystal X-ray diffraction, combined with a Cambridge Structural Database survey of (H2PO4–)n aggregates, established that these clusters display unique topologies and hydrogen-bonding connectivities.
- Published
- 2013
45. Gui-ling-gao (turtle jelly), a traditional Chinese functional food, exerts anti-inflammatory effects by inhibiting iNOS and pro-inflammatory cytokine expressions in splenocytes isolated from BALB/c mice
- Author
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De Jian Guo, Ching Ching Lau, Shun Wan Chan, Daniel K. W. Mok, Chi-On Chan, Chun Wai Wan, Huan Zhang, and Min Yi Wu
- Subjects
medicine.medical_specialty ,Lipopolysaccharide ,medicine.medical_treatment ,Pro-inflammatory cytokines ,Medicine (miscellaneous) ,Inflammation ,Pharmacology ,BALB/c ,Proinflammatory cytokine ,chemistry.chemical_compound ,Internal medicine ,medicine ,Splenocyte ,TX341-641 ,Splenocytes ,Nutrition and Dietetics ,biology ,Nutrition. Foods and food supply ,biology.organism_classification ,Turtle jelly ,Nitric oxide synthase ,Endocrinology ,Cytokine ,chemistry ,biology.protein ,TLR4 ,medicine.symptom ,Anti-inflammatory ,Food Science - Abstract
Gui-ling-gao (GLG), also known as turtle jelly, is a popular medicinal Chinese health/functional food prepared from several traditional Chinese medicinal herbs. The present study aimed at examining and explaining the anti-inflammatory properties of GLG by using lipopolysaccharide (LPS)-induced inflammation in splenocytes isolated from BALB/c mice. Additionally, the effects of GLG on mRNA and protein expressions of inducible nitric oxide synthase (iNOS) and pro-inflammatory cytokines in LPS-stimulated splenocyte proliferation were evaluated by real-time RT-PCR and Western blot assays. We demonstrated that GLG significantly inhibited LPS-induced splenocyte proliferation in a concentration-dependent manner. LPS-mediated up-regulations in the gene and protein expressions of iNOS, interleukin-1β (IL-1β) and tumour necrosis factor-alpha (TNF-α) were suppressed by GLG. These findings suggest for the first time that GLG exerts anti-inflammatory effects by inhibiting the expression of iNOS and pro-inflammatory cytokines such as IL-1β and TNF-α. The current study provides strong scientific evidence for the health-beneficial claim that consumption of GLG could help the body to modulate the immune system.
- Published
- 2013
46. A Review of the Phytochemistry and Pharmacological Activities of Raphani Semen
- Author
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Ailsa Chui Ying Yuen, Shun Wan Chan, Yam Fung Ng, Chi-On Chan, Tung-Ting Sham, and Daniel K. W. Mok
- Subjects
endocrine system ,food.ingredient ,Raphanus ,Semen ,Review Article ,Traditional Chinese medicine ,Pharmacology ,chemistry.chemical_compound ,fluids and secretions ,food ,Medicine ,Adverse effect ,chemistry.chemical_classification ,biology ,business.industry ,food and beverages ,Fatty acid ,lcsh:Other systems of medicine ,lcsh:RZ201-999 ,biology.organism_classification ,Complementary and alternative medicine ,chemistry ,Erucic acid ,Herb ,Toxicity ,business - Abstract
The dried ripe seed ofRaphanus sativusL., commonly known as radish seed (or Raphani Semen), is used as traditional Chinese medicine (TCM) to treat constipation, chronic tracheitis, and hypertension. The major active compounds in Raphani Semen are alkaloids, glucosinolates, brassinosteroids, and flavonoids. Fatty acids are its main nutritional contents. Raphani Semen has been demonstrated to have beneficial effects on hypertension, obesity, diabetes mellitus, constipation, and cough. So far, there is no report about the adverse/toxic effects of this herb on humans. However, Raphani Semen processed by roasting was reported to exhibit some adverse effects on mice. Additionally, erucic acid, the main fatty acid in Raphani Semen, was shown to enhance the toxicity of doxorubicin. Thus, Raphani Semen has a potential risk of causing toxicity and drug interaction. In summary, Raphani Semen is a valuable TCM herb with multiple pharmacological effects. More studies on Raphani Semen could help better understand its pharmacological mechanisms so as to provide clear scientific evidence to explain its traditional uses, to identify its therapeutic potential on other diseases, and to understand its possible harmful effects.
- Published
- 2013
47. Ligusticum chuanxiong Prevents Ovariectomy-Induced Liver and Vascular Damage in Rats
- Author
-
Xue Lian Tian, De Jian Guo, Xiao-Li Dong, Zhen Yu He, Ri Fu Yang, Tai Qiu Qiu, Man Sau Wong, Shun Wan Chan, Chun Mei Li, and Jian Hong Wu
- Subjects
medicine.medical_specialty ,Antioxidant ,Nitric Oxide Synthase Type III ,Endothelium ,Ovariectomy ,medicine.medical_treatment ,Aorta, Thoracic ,Nitric Oxide ,Weight Gain ,Antioxidants ,Nitric oxide ,Rats, Sprague-Dawley ,chemistry.chemical_compound ,High-density lipoprotein ,Non-alcoholic Fatty Liver Disease ,Internal medicine ,medicine ,Animals ,Ligusticum ,Estradiol ,medicine.diagnostic_test ,Plant Extracts ,Cholesterol ,business.industry ,Fatty liver ,Estrogens ,General Medicine ,medicine.disease ,Lipids ,Rats ,Fatty Liver ,Postmenopause ,Vasodilation ,medicine.anatomical_structure ,Endocrinology ,Liver ,Complementary and alternative medicine ,chemistry ,Ovariectomized rat ,Female ,Endothelium, Vascular ,Lipid profile ,business ,Rhizome ,Drugs, Chinese Herbal ,Phytotherapy - Abstract
Post-menopause, there is an increase in body weight, visceral adiposity, and risk of developing non-alcoholic fatty liver disease (NAFLD), which leads to various cardiovascular diseases (CVDs). Some natural products have proven useful for counteracting the detrimental effects of menopause. The rhizome of Ligusticum chuanxiong Hort. (LC) is a well-known medicinal herb widely used in Chinese communities for the treatment of CVDs. The hepatic and vascular protective effects of LC ethanolic extract under postmenopausal conditions were investigated on ovariectomized (OVX) rats supplemented with or without LC ethanolic extract (600 mg/kg body weight/day, p.o.) or 17β-estradiol (1 mg/kg body weight/day, p.o.) for 12 weeks. The current findings demonstrated that consumption of LC ethanolic extract could reduce the body weight gain, improve serum lipid profile (lowering low density lipoprotein cholesterol but raising high density lipoprotein cholesterol), combat NAFLD, and protect vascular endothelium in the OVX rats. The beneficial effects of LC may be associated with its antioxidant or vasorelaxant compounds, which enhance the levels of hepatic antioxidant enzymes and up-regulate endothelial nitric oxide synthase mRNA expression, respectively. Taken together, LC may be a promising natural supplement for postmenopausal women to prevent NAFLD and CVDs.
- Published
- 2013
48. A Research of the Spongy Foams from Interpenetrating Polymer Network of Polyurethane/ Epoxy Resin
- Author
-
Hong Jun Huang, Wang Kang, Guo Shun Wan, and Jiang Lei
- Subjects
chemistry.chemical_classification ,Materials science ,General Engineering ,Epoxy ,Adhesion ,Polymer ,chemistry.chemical_compound ,chemistry ,Polymerization ,visual_art ,visual_art.visual_art_medium ,Interpenetrating polymer network ,Fourier transform infrared spectroscopy ,Composite material ,Polyurethane - Abstract
A series of interpenetrating polymer networks (IPN) spongy foams based on polyurethane (PU) and epoxy resin (EP) were prepared by a simultaneous polymerization technique. The PU/EP IPN spongy foams with different epoxy content were investigated. The results showed that initial adhesion increased with the increment of EP content, and gained the highest value when the content reached to 20%; FTIR suggested the formation of PU/EP IPN; the density also increased with the increasing content of epoxy; the highest degree of uniformity in bubbles were observed in foams with 20% content of epoxy resin.
- Published
- 2012
49. Danshensu is the major marker for the antioxidant and vasorelaxation effects of Danshen (Salvia miltiorrhiza) water-extracts produced by different heat water-extractions
- Author
-
Pou Seng Choi, Francis F.Y. Lam, Penelope M.Y. Or, Jia-Ming Yang, Shun Wan Chan, Hui Ling Tseng, Simon Ming-Yuen Lee, Xuelin Zhou, John H.K. Yeung, Pui Man Hoi, Yiu Wa Kwan, Yan Deng, George P.H. Leung, Siu Kai Kong, and Ho-Pui Ho
- Subjects
Erythrocytes ,Hot Temperature ,Antioxidant ,DPPH ,Vasodilator Agents ,medicine.medical_treatment ,Amidines ,Pharmaceutical Science ,Apoptosis ,Salvia miltiorrhiza ,Ferric Compounds ,Hemolysis ,Antioxidants ,Cell Line ,chemistry.chemical_compound ,Phenols ,Picrates ,Drug Discovery ,medicine ,Animals ,Humans ,Hydrogen peroxide ,Pharmacology ,Chromatography ,Traditional medicine ,Chemistry ,Biphenyl Compounds ,Extraction (chemistry) ,Heart ,Water extraction ,Hydrogen Peroxide ,Phenolic acid ,medicine.disease ,Rats ,Vasodilation ,Complementary and alternative medicine ,Basilar Artery ,Abietanes ,Lactates ,Molecular Medicine ,Drugs, Chinese Herbal - Abstract
Some of the major components of Danshen (Salvia miltiorrhiza), a widely used Chinese herbal medicine rich in phenolic acids, are thermosensitive and may degrade to other phenolic acids during extractions with heating. The chemical profiles of Danshen water-extract may vary with different heat water extraction at different temperatures, affecting the composition and bioactivity of the extracts. In this study, six water-extracts of Danshen obtained from heat reflux water extraction and microwave-assisted extraction with water (MAE-W) at different temperatures were tested for their composition and pharmacological effects. Among these extracts, the third-round MAE-W (100°C) extract had the highest phenolic acids and tanshinones contents, with the strongest antioxidant activity in 2,2-diphenyl-1-(2,4,6-trinitrophenyl) hydrazyl (DPPH) assay and ferric reducing/antioxidant potential (FRAP) assay. This extract also showed the strongest inhibitory effects on 2,2'-azobis-2-amidinopropane (AAPH)-induced hemolysis in human red blood cells, hydrogen peroxide-induced apoptosis in rat heart H9c2 cells and the highest relaxation effects on rat basilar artery. The antioxidant effects of Danshen water-extracts linearly correlated to their relaxation effects (r=0.895-0.977). Through multiple linear regression analysis, danshensu was found to be the most significant marker in the antioxidant and vasodilation effects of Danshen water-extract, while tanshinone IIA as the marker on hydrogen peroxide-induced apoptosis in rat heart H9c2 cells. Danshensu is, therefore, a useful marker for the quality control of Danshen water-extracts in antioxidant and vasodilation, while tanshinone IIA for anti-apoptotic potential of different extracts.
- Published
- 2012
50. Chemical and pharmacological evaluations on the extract of Scutellaria baicalensis Georgi (Huang-Qin) prepared by various extraction methods
- Author
-
Pou Seng Choi, Jia-Ming Yang, Siu Kai Kong, Pui Man Hoi, Melody Yee-Man Wong, Shun Wan Chan, Simon Ming-Yuen Lee, George P.H. Leung, Penelope M.Y. Or, Ho-Pui Ho, John H.K. Yeung, Sai-Ming Ngai, Xuelin Zhou, and Yiu Wa Kwan
- Subjects
Antioxidant ,medicine.medical_treatment ,Antioxidant properties ,01 natural sciences ,Flavones ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,medicine ,chemistry.chemical_classification ,Multidisciplinary ,Ethanol ,biology ,Traditional medicine ,Scutellaria baicalensis Georgi ,Research ,010401 analytical chemistry ,Extraction (chemistry) ,biology.organism_classification ,Extraction efficiency ,0104 chemical sciences ,chemistry ,Herb–drug interaction ,030220 oncology & carcinogenesis ,Yield (chemistry) ,Microsome ,Scutellaria baicalensis ,Extraction methods - Abstract
Background This study reported a comprehensive approach (comparing the extraction yields, chemical profiles, antioxidant properties and CYP450-inhibitory effects) to evaluated the effectiveness of various extraction methods [microwave-assisted extraction using water (MAE-W), heat reflux extraction using water (HRE-W), ultrasonic extraction using 70 % ethanol and ultrasonic extraction using ethanol (UE-E)] for Huang-Qin (HQ), the dried root of Scutellaria baicalensis Georgi. Results The HQ extraction efficiency by MAE-W was the best. The chemical profiles of extracts obtained using HRE-W and MAE-W were similar; whereas more flavones but less flavone glycosides were detected in the UE-E extract. There was no difference in the antioxidant properties among different extracts. In vitro human liver microsome assays illustrated that all extracts possessed herb–drug interaction potentials but the UE-E extract are shown with a potent interaction with CYP3A4-metabolized drugs. Conclusion MAE-W is a favorable method for the preparation of HQ extracts based on extraction yield, pharmacological properties and safety.
- Published
- 2016
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