468 results on '"Ping Tan"'
Search Results
2. Production of ‘kedondong’ (Spondias cytherea Sonnerat) powder as affected by different drying methods [pdf]
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Kar Lin Nyam, Chin Ping Tan, Kar Qi Lau, Lee Sin Chang, Yus Aniza Yusof, and Liew Phing Pui
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Ingredient ,Freeze-drying ,chemistry.chemical_compound ,Materials science ,chemistry ,Water activity ,DPPH ,Spray drying ,Food science ,Drum drying ,Shelf life ,Water content ,Food Science - Abstract
BACKGROUND ‘Kedondong’ fruit is regarded as an exotic fruit that is gaining popularity due to its deliciousness and pleasant flavour. However, this fruit has a short shelf life, leading to problems with postharvest loss. In order to prevent losses, the fruit could be produced as a value-added product. In this study, the ‘kedondong’ fruit was preserved by drying into powder using different drying methods. METHODS The kedondong powder was dried using five methods: convection oven drying, vacuum drying, spray drying, drum drying and freeze drying. The physical properties, flowability and DPPH radical scavenging ability of dried kedondong powder were examined. RESULTS Spray-dried powder provided the significantly (p ≤ 0.05) highest process yield, which was 54.93%. All the powder produced had a low moisture content (3.03 to 5.66%) and water activity (0.19–0.37). Visually, whitish and fine powders were observed on spray-dried and freeze-dried samples, while convection oven-dried and vacuum-dried powder appeared yellowish and coarse. The pH of the reconstituted powders varied from 2.71 to 2.83, where drum-dried powder was the most acidic. Spray-dried powder showed the highest wettability and shortest dissolution time, which was 172.65 s and 10.55 s, respectively. With the exception of drum-dried powder, all the dried powders were classified as non-caking powders. The bulk and tapped density of the powders ranged from 0.32 to 0.70 g/mL and 0.38 to 0.86 g/mL, respectively. Vacuum-dried powder had very good flowability, convection oven-dried and drum-dried powder had good flowability, while spray-dried and drum-dried powder had fair flowability. Antioxidant assay showed that freeze-dried powder exhibited the highest free radical scavenging activity (IC50 = 701.29 μg/mL). CONCLUSIONS This study indicates that spray-dried kedondong powder has great potential in the food industry due to its high process yield and better powder quality. Meanwhile, freeze drying best preserved the antioxidant properties of the powder, which could potentially be used as a functional ingredient as a result. This study is important for the fruit processing industry as it offers an alternative for the farmer to produce kedondong fruit powder because the fruit has a short shelf life. Converting the fruit into powder can diversify the resulting produce into different applications, such as fruit juice, beverages, jam and other food products.
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- 2021
3. Asymmetric Construction of Tertiary/Secondary Carbon–Phosphorus Bonds via Bifunctional Phosphonium Salt Catalyzed 1,6-Addition
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Zhaoyuan Yu, Tian Li Wang, Yu Lan, Zhiyu Jiang, Yuan Chen, Xiaoyu Ren, Jia-Hong Wu, and Jian-Ping Tan
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chemistry.chemical_compound ,chemistry ,Phosphorus ,Polymer chemistry ,Phosphonium salt ,chemistry.chemical_element ,General Chemistry ,Bifunctional ,Carbon ,Catalysis - Published
- 2021
4. Ethyl caffeate ameliorated amyloid‐beta42 protein‐associated toxicity in <scp>PC12</scp> cells and Drosophila melanogaster
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Nurulhuda Athirah Binti Hadri, Ghows Azzam, Nazalan Najimudin, Nobumoto Watanabe, and Florence Hui Ping Tan
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Programmed cell death ,Amyloid beta-Peptides ,biology ,Amyloid ,business.industry ,Ethyl caffeate ,Pharmacology ,biology.organism_classification ,PC12 Cells ,Phenotype ,Peptide Fragments ,Rats ,Disease Models, Animal ,chemistry.chemical_compound ,Caffeic Acids ,Drosophila melanogaster ,chemistry ,Alzheimer Disease ,Toxicity ,Animals ,Medicine ,business ,Drosophila - Abstract
AIM Alzheimer's disease (AD) is the most pervasive neurodegenerative disorder in societies globally. Till now, the mechanism behind this disease is still equivocal. Amyloid-beta42 protein (Aβ42), the most toxic and aggressive Aβ species, is the main focus of this study. The naturally occurring ethyl caffeate (EC) is associated with various medicinal properties. Here, EC was tested for its protective properties against Aβ42's toxic effects. METHODS As treatment of Aβ42 has been shown to cause neuronal cell death, EC was first screened with Aβ42-incubated PC12 neuronal cells. Next, the compound was tested on the Drosophila melanogaster AD model using the rough eye phenotype assay, lifespan assay and negative geotaxis assay. RESULTS EC ameliorated PC12 cells from cell death linked to Aβ42 exposure. Using Drosophila expressing human Aβ42, feeding of EC was able to partially rescue the rough eye phenotype, lengthen the lifespan of AD Drosophila and enhanced the mobility of middle-aged AD Drosophila. CONCLUSION Overall, the results of this study showed that EC might possess therapeutic properties for AD. Geriatr Gerontol Int 2021; 21: 1125-1130.
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- 2021
5. A summary of 2-, 3-MCPD esters and glycidyl ester occurrence during frying and baking processes
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Kok Ming Goh, Kar Lin Nyam, Chin Ping Tan, and Yu Hua Wong
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Review Article ,Applied Microbiology and Biotechnology ,Chloride ,Food processing and manufacture ,Monochloropropandiol ,chemistry.chemical_compound ,Hydrolysis ,3-MCPD ,medicine ,Glycidyl ester ,Organic chemistry ,TX341-641 ,Lipase ,Refining (metallurgy) ,biology ,Nutrition. Foods and food supply ,Vegetable oil refining ,Glycidol ,food and beverages ,TP368-456 ,Decomposition ,chemistry ,biology.protein ,Frying ,Food Science ,Biotechnology ,medicine.drug ,Baking - Abstract
Monochloropropanediol (MCPD) esters and glycidyl esters (GE) are the process contaminants found in frying and baking, except the refining process. The free form MCPD and glycidol are released from their parent esters via lipase hydrolysis while they are carcinogen and genotoxic carcinogen, respectively. MCPD esters and GE are formed endogenously during vegetable oil refining process. Then, their concentration were experimented during subsequent food processing methods, especially frying and baking. This review discussed the occurrence of 2-, 3-MCPD esters and GE during frying and baking processes. Process temperature, process duration, presence of precursors, and their combined effects are highly related to MCPD esters and GE formations. An elevated temperature and processing time can increase the formation of these contaminants until an optimum rate and then followed by the decomposition. Also, other factors such as the presence of chloride ions, moisture, and partial acylglycerol can further facilitate MCPD esters and/or GE formation., Graphical abstract Image 1, Highlights • Frying and baking trigger formation of MCPD esters and GE. • MCPD esters and GE are formed endogenously during refining process. • The concentration of MCPD esters and GE elevated during thermal processing. • Temperature, process duration, and precursors cause MCPD esters and GE formations.
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- 2021
6. Optimizing the route for medium temperature-activated carbon derived from agro-based waste material
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Yen Ping Tan, Aloysius Akaangee Pam, Abdul Halim Abdullah, and Zulkarnain Zainal
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Aqueous solution ,Materials science ,Renewable Energy, Sustainability and the Environment ,Carbonization ,020209 energy ,02 engineering and technology ,010501 environmental sciences ,01 natural sciences ,chemistry.chemical_compound ,Adsorption ,chemistry ,Chemical engineering ,Volume (thermodynamics) ,Palm kernel ,0202 electrical engineering, electronic engineering, information engineering ,medicine ,Phosphoric acid ,0105 earth and related environmental sciences ,Activated carbon ,medicine.drug ,BET theory - Abstract
In this present study, activated carbon was successfully prepared from palm kernel shell (PKS) by chemical activation method using phosphoric acid (H3PO4). The optimum conditions, the influence of process parameters such as temperature (400–00 °C), and impregnation ratio on the BET surface area and pore volume of the activated carbons (AC) were investigated. Among the variables, the impregnation ratio was found to be the most influential. Under optimum conditions, activated carbon with surface area of 1267 m2/g was obtained at medium temperature (500 °C), impregnation ratio of 2:1, and shorter carbonization time of 1 h. The aqueous adsorption test demonstrated that showed that the AC had a remarkable removal capacity for methylene blue.
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- 2021
7. Pickering emulsion‐templated ionotropic gelation of tocotrienol microcapsules: effects of alginate and chitosan concentrations and gelation process parameters
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Yong Wang, Hon Weng Chang, Tai Boon Tan, Beng Ti Tey, Chin Ping Tan, William Wachira Mwangi, Yuanfa Liu, Eng Seng Chan, Oi Ming Lai, and Phui Yee Tan
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Chitosan ,Nutrition and Dietetics ,Biocompatibility ,Alginates ,Drug Compounding ,Tocotrienols ,Chitosan coating ,Capsules ,Hydrogen-Ion Concentration ,Biocompatible material ,Wall material ,Pickering emulsion ,chemistry.chemical_compound ,Calcium carbonate ,chemistry ,Chemical engineering ,Emulsions ,Tocotrienol ,Gels ,Agronomy and Crop Science ,Food Science ,Biotechnology - Abstract
Background Throughout the past decade, Pickering emulsion has been increasingly utilized for the encapsulation of bioactive compounds due to its high stability and biocompatibility. In the present work, palm tocotrienols were initially encapsulated in a calcium carbonate Pickering emulsion, which was then subjected to alginate gelation and subsequent chitosan coating. The effects of wall material (alginate and chitosan) concentrations, gelation pH and time, and chitosan coating time on the encapsulation efficiency of palm tocotrienols were explored. Results Our findings revealed that uncoated alginate microcapsules ruptured upon drying and exhibited low encapsulation efficiency (13.81 ± 2.76%). However, the addition of chitosan successfully provided a more complex and rigid external wall structure to enhance the stability of the microcapsules. By prolonging the crosslinking time from 5 to 30 min and increasing the chitosan concentration from 0.1 to 0.5%, the oil encapsulation efficiency was increased by 28%. Under the right gelation pH (pH 4), the extension of gelation time from 1 to 12 h resulted in an increase in alginate-Ca2+ crosslinkings, thus strengthening the microcapsules. Conclusion With the optimum formulation and process parameters, a high encapsulation efficiency (81.49 ± 1.75%) with an elevated oil loading efficiency (63.58 ± 2.96%) were achieved. The final product is biocompatible and can potentially be used for the delivery of palm tocotrienols. This article is protected by copyright. All rights reserved.
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- 2021
8. Response surface methodology optimization study on corncob pretreatment: reduction of sodium hydroxide usage and enhancement in pulpzyme HC biobleaching efficiency
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Teck-Kim Tang, N. A. Jamalullail, Eng Tong Phuah, Yong Wang, Sivaruby Kanagaratnam, Ling-Zhi Cheong, Joo Shun Tan, Oi-Ming Lai, Yee Ying Lee, Chin Ping Tan, Choon Min Lee, and K. L. Yap
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Reduction (complexity) ,chemistry.chemical_compound ,biology ,Chemistry ,Sodium hydroxide ,biology.protein ,Response surface methodology ,Cellulase ,Corncob ,Food Science ,Nuclear chemistry - Abstract
Lignocellulosic rich corncob biomass possesses less complex structure, lignin and pigment content. As compared to wood pulp, it is considered to be a better alternative for the production of cellulose fibre. The present study was conducted to optimize both the alkaline (using sodium hydroxide) and biobleaching (using Pulpzyme HC) pretreatment process of corncob to promote lignin removal and cellulose swelling. It was the aim of this work to achieve mild processing conditions for corncob pretreatment in order to minimize the chemical usage. Results demonstrated that the mild pretreatment approach employed was found to successfully increase cellulose swelling and lignin removal from the corncob biomass. In alkaline pretreatment process, reaction temperature showed to be the most prominent effect in enhancing lignin removal and cellulose swelling as compared to sodium hydroxide concentration and reaction time. RSM optimized conditions for alkaline pretreatment process: 0.5 M NaOH, reaction temperature of 80°C and reaction time of 30 mins manage to increase the sedimentation index (indicate swelling of cellulose) from 0 to 30 and reduce the kappa number (represent lignin removal) from 82 to 32, respectively. Meanwhile, for biobleaching pretreatment using Pulpzyme HC, reaction time play a more significant role than the Pulpzyme HC concentration in promoting lignin removal and increasing cellulose swelling. RSM optimized conditions showed that the kappa number was reduced from 32 to 18 whereas the sedimentation index increased from 30 to 60 when the alkaline pretreated corncob was biobleached with Pulpzyme HC.
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- 2021
9. Encapsulation of caffeine into starch matrices: Bitterness evaluation and suppression mechanism
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Supaluck Kraithong, Qing Gao, Bin Zhang, Songnan Li, Chin Ping Tan, Qiang Huang, Miao Shao, and Xiong Fu
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Starch ,Drug Compounding ,Kinetics ,Capsules ,02 engineering and technology ,Molecular Dynamics Simulation ,Biochemistry ,Porous starch ,Modified starch ,03 medical and health sciences ,chemistry.chemical_compound ,Drug Delivery Systems ,Structural Biology ,Caffeine ,Humans ,Particle Size ,Electronic Nose ,Molecular Biology ,030304 developmental biology ,0303 health sciences ,Alkaloid ,beta-Cyclodextrins ,food and beverages ,Hydrogen Bonding ,General Medicine ,021001 nanoscience & nanotechnology ,Drug Liberation ,chemistry ,Taste ,Amylose ,0210 nano-technology ,Porosity ,Nuclear chemistry - Abstract
In this study, caffeine (CA) was encapsulated into food-grade starch matrices, including swelled starch (SS), porous starch (PS), and V-type starch (VS). The bitterness of the microcapsules and suppression mechanisms were investigated using an electronic tongue, molecular dynamics (MD) simulation and the in vitro release kinetics of CA. All the CA-loaded microcapsules showed a lower bitterness intensity than the control. The MD results proved that the weak interactions between starch and CA resulted in a moderate CA release rate for SS-CA microcapsules. The PS-CA microcapsule presented the longest CA release, up to 40 min, whereas the VS-CA microcapsule completely released CA in 9 min. The CA release rate was found to be related to the microcapsule structure and rehydration properties. A low CA bitterness intensity could be attributed to a delay in the CA release rate and resistance to erosion of the microcapsules. The results of this work are valuable for improving starch-based microcapsules (oral-targeted drug-delivery systems) by suppressing the bitterness of alkaloid compounds.
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- 2021
10. Ceibapentandra (L.) Gaertn (Kapok) Seed Fibre as a Recycled Paper Reinforcement Pulp
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Junidah Lamaming, Wen Ping Tan, Choon Fu Goh, Cheu Peng Leh, Mohamad Haafiz Mohamad Kassim, and Rokiah Hashim
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0106 biological sciences ,Environmental Engineering ,Renewable Energy, Sustainability and the Environment ,Chemistry ,Starch ,020209 energy ,Pulp (paper) ,Paper production ,02 engineering and technology ,engineering.material ,Pulp and paper industry ,01 natural sciences ,Chemical pulping ,stomatognathic diseases ,chemistry.chemical_compound ,stomatognathic system ,Sodium hydroxide ,010608 biotechnology ,0202 electrical engineering, electronic engineering, information engineering ,Chemical pulp ,engineering ,Reinforcement ,Waste Management and Disposal - Abstract
The kapok (Ceibapentandra (L.) Gaertn) seed fibre is unicellular with length up to 35 mm, however, it is covered by a hydrophobic waxy layer that limits its application in paper production. In this study, the effect of various pulping methods namely mechanical, chemi-mechanical, semichemical and chemical pulping on kapok fibre properties was investigated. Each kapok pulp was then blended with the secondary fibre recovered from kraftliner board for handsheet making to examine their reinforcing ability on strength properties. The results showed that kapok mechanical pulps (with and without dewaxing (5% (v/v) diluted detergent) and chemimechanical pulp were unable to improve the strength properties of the handsheet. Kapok pulps chemically treated with 18–25% of sodium hydroxide gave a better effect on handsheet strength properties whilst fibre treated with 20% sodium hydroxide showing the highest increment. Although the reinforcing effect of the 4% native cooked starch was slightly higher than that of the 10% kapok pulp blended in recycled paper, the recycling potential of the latter was better as all strength properties retained unchanged after recycling. The findings indicated that kapok chemical pulp is a promising reinforcing fibre source with superior recycling potential.
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- 2021
11. Enzymatic Interesterification of Palm Stearin and Palm Olein Blend Catalyzed by sn-1,3-Specific Lipase: Interesterification Degree, Acyl Migration, and Physical Properties
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Yong Wang, Wan Jun Lee, Aijun Li, Xiaodong Xie, Oi Ming Lai, Jing Ye, Chin Ping Tan, and Zhen Zhang
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chemistry.chemical_classification ,Esterification ,biology ,Interesterified fat ,Fatty Acids ,Fatty acid ,Lipase ,General Chemistry ,Palm Oil ,Catalysis ,Palm stearin ,chemistry.chemical_compound ,chemistry ,biology.protein ,Plant Oils ,Organic chemistry ,Enzymatic interesterification ,General Agricultural and Biological Sciences ,Selectivity ,Triglycerides ,Acyl group - Abstract
Acyl migration of fatty acid at sn-2 is often observed alongside enzymatic interesterification (EIE), causing the loss of lipase selectivity toward the acyl group at sn-1,3. In this study, an oil blend consisting of palm stearin (PST) and palm olein (POL) was interesterified via a chemical interesterification (CIE) and enzymatic method using a packed bed reactor. Characterization in terms of the triacylglycerol (TAG) compositions, sn-2 fatty acid distributions, and solid fat content profiles was performed. In comparison to that of CIE fats, EIE fats showed different modification effects on the solid fat content. Under similar reaction conditions, different interesterification degrees (IDs) were obtained according to the various blend ratios. Using the same mass ratio of substrates (POL/PST of 9:1), the EIE reaction time and temperature affected the ID and the change in the fatty acyl group at the sn-2 position. Under the reaction time of 46 min, an ID of 94.41% was acquired, while at 80 °C, the degree of acyl migration at sn-2 was 92.87%. EIE with high acyl migration exhibited a lower crystallization rate than that of EIE with low acyl migration. However, the effect of acyl migration on crystal polymorphism and oxidative stability was insignificant. Outcomes from this study are meaningful for the establishment of a theoretical basis for a controlled positional-specific EIE that is catalyzed by sn-1,3-specific lipase.
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- 2021
12. Visible-light-induced tandem radical addition/cyclization of 2-alkenylphenols and CBr4 for the synthesis of 4-arylcoumarins
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Wen-Jing Xiao, Dong Liang, Jia-Rong Chen, Ying Cheng, and Li-Ping Tan
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Reaction conditions ,Tandem ,010405 organic chemistry ,media_common.quotation_subject ,Organic Chemistry ,010402 general chemistry ,01 natural sciences ,Combinatorial chemistry ,0104 chemical sciences ,chemistry.chemical_compound ,chemistry ,Functional group ,Simplicity ,Visible spectrum ,media_common - Abstract
A visible-light-induced photoredox-catalyzed tandem radical addition/cyclization of 2-alkenylphenols and CBr4 is developed. This protocol features mild and redox-neutral reaction conditions, good functional group tolerance, and operational simplicity, providing efficient and practical access to various 4-arylcoumarins in a one-pot fashion. Preliminary mechanistic investigations confirm a radical process and the significant role of the additive water.
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- 2021
13. Biomimetic self-assembly of lipase-zeolitic imidazolate frameworks with enhanced biosensing of protox inhibiting herbicides
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Oi-Ming Lai, Cai Shen, Ling-Zhi Cheong, Chin Ping Tan, and Chuanchuan Cheng
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Conformational change ,General Chemical Engineering ,Analytical Chemistry ,chemistry.chemical_compound ,Biomimetics ,Imidazolate ,Humans ,Protoporphyrinogen Oxidase ,Lipase ,Metal-Organic Frameworks ,biology ,Herbicides ,fungi ,technology, industry, and agriculture ,General Engineering ,food and beverages ,Substrate (chemistry) ,Nitrofen ,Combinatorial chemistry ,Candida rugosa ,Electrochemical gas sensor ,chemistry ,Zeolites ,biology.protein ,Zeolitic imidazolate framework - Abstract
Protox inhibiting herbicides such as nitrofen have detrimental effects on the environment and human health. The current work aims to fabricate a Candida rugosa lipase (CRL)-based electrochemical sensor for rapid and sensitive detection of protox inhibiting herbicides (nitrofen). We proposed the use of poly(vinylpyrrolidone) (PVP) and amino-acids to promote accumulation of Zn2+ ions at the surfaces of Candida rugosa lipase (CRL) and subsequently induce self-assembly of a CRL-zeolitic imidazolate framework (ZIF) structure. This process can be easily and rapidly achieved via a one-pot facile self-assembly method. Steady-state fluorescence spectroscopy indicated that CRL has undergone a conformational change following encapsulation within the ZIF structure. This conformational change is beneficial as the prepared PVP/Glu/CRL@ZIF-8 exhibited enhanced catalytic activity (207% of native CRL), and higher substrate affinity (lower Km than native CRL) and showed high stability under harsh denaturing conditions. PVP/Glu/CRL@ZIF-8 was finally used for electrochemical biosensing of nitrofen. The fabricated biosensor has a wide linear detection range (0–100 μM), a lower limit of detection and a good recovery rate.
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- 2021
14. Mitochondria-targeted cyclometalated rhodium(<scp>iii</scp>) complexes: synthesis, characterization and anticancer research
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Xiao-Lan Zhong, Ping Zhao, Qiang Niu, Cai-Ping Tan, Yan-Bo Peng, Wei He, and Can Tao
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Cisplatin ,chemistry.chemical_classification ,Reactive oxygen species ,biology ,Stereochemistry ,Phenanthroline ,Cytochrome c ,chemistry.chemical_element ,Apoptosis ,Mitochondrion ,Ruthenium ,Mitochondria ,Rhodium ,Inorganic Chemistry ,chemistry.chemical_compound ,chemistry ,medicine ,biology.protein ,Reactive Oxygen Species ,medicine.drug - Abstract
Over the past few decades, the landscape of inorganic medicinal chemistry has been dominated by investigations on platinum or ruthenium, while the research based on other metal centers such as rhodium has been relatively insufficient. In this work, a series of cyclometalated rhodium(iii) complexes with imidazo[4,5-f][1,10]phenanthroline containing different aromatic rings were synthesized and characterized. Notably, all the complexes displayed stronger anticancer activity against various cancer cells compared with cisplatin. A mechanism study revealed that the rhodium complexes accumulated in the mitochondria, elevated the levels of mitochondrial reactive oxygen species (ROS) and released cytochrome c, indicating severe mitochondrial damage during the anticancer activity. Further studies illustrated that the rhodium complexes caused cell cycle arrest at the G2/M phase, upregulated the expression of p53 and reduced the ratio of B-cell lymphoma-2 (Bcl-2)/Bcl-2-associated x (Bax), which ultimately resulted in cellular apoptosis. Overall, through mitochondrial pathways, these Rh(iii) complexes could induce cellular apoptosis to a larger extent than cisplatin and should be paid close attention as promising chemotherapeutic drugs in anticancer research.
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- 2021
15. Numerical design of dual-scale foams to enhance radiation absorption
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Yang Li, Fuqiang Wang, He-Ping Tan, Chang-Hua Lin, Xin-Lin Xia, and Hong-Wei Chen
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structure design ,TK1001-1841 ,porous strut ,Materials science ,Renewable Energy, Sustainability and the Environment ,Energy Engineering and Power Technology ,Radiant energy ,radiation ,chemistry.chemical_compound ,Production of electric energy or power. Powerplants. Central stations ,Fuel Technology ,chemistry ,visual_art ,Absorptance ,visual_art.visual_art_medium ,Silicon carbide ,Radiative transfer ,Cubic zirconia ,dual-scale foam (dsf) ,Ceramic ,Composite material ,Porosity ,Absorption (electromagnetic radiation) ,semitransparent - Abstract
Unlike silicon carbide ceramic, the alumina ceramic and zirconia ceramic are by its very nature weakly absorbing in visible and near infrared wavebands. Therefore, open-cell foams made of such ceramics are rarely used in applications requiring strong absorption of radiation energy, such as solar absorbers. In order to improve the potential of such foams, open-cell foams with dual-scale pores were digitally designed in the limit of geometric optics. The first-order pores are obtained by Voronoi tessellation technique and then the second-order pores are realized by the design of 'porous strut'. A Monte Carlo Ray-tracing method is applied in the dual-scale foam structure for radiative transfer calculation. The parameterized study is conducted on the radiation absorption of alumina foam sheets and zirconia foam sheets. The results show that for the present cases, the designed dual-scale alumina foams with strut porosity p s = 0.3 can increase the normal absorptance within the wavebands from 0.4 μm to 7.0 μm by 62.7% than the foams with single-scale pores. For the zirconia foams, this increase is 115.9% within the wavebands from 1.2 μm to 7.6 μm. The findings can provide strong confidence on dual-scale foams to enhance the absorption of radiation energy in potential applications.
- Published
- 2021
16. Tailored rigidity of W/O Pickering emulsions using diacylglycerol-based surface-active solid lipid nanoparticles
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Yong Wang, Wan Jun Lee, Guoyan Li, Chin Ping Tan, Oi Ming Lai, and Chaoying Qiu
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Water ,Sodium stearoyl lactylate ,General Medicine ,Pickering emulsion ,law.invention ,Diglycerides ,Contact angle ,Sonication ,Surface-Active Agents ,chemistry.chemical_compound ,chemistry ,Pulmonary surfactant ,Chemical engineering ,law ,Liposomes ,Solid lipid nanoparticle ,Nanoparticles ,Emulsions ,Adsorption ,Wetting ,Particle size ,Crystallization ,Food Science - Abstract
Pickering water-in-oil (W/O) emulsions were fabricated by using medium-long chain diacylglycerol (MLCD)-based solid lipid nanoparticles (SLNs) and the connection between the characteristics of the SLNs and the colloidal stability of the emulsions was established. Via melt-emulsification and ultrasonication, MLCD-based SLNs with particle sizes of 120–300 nm were obtained with or without other surfactants. The particle size of the SLNs was influenced by the chemical properties of the surfactants, and surfactants decreased the contact angle of SLNs at the oil–water interface. Gelation was observed in SLNs modified by sodium stearoyl lactylate and lecithin, whereas the addition of Tween 20 resulted in a homogeneous SLN solution. The adsorption of surfactants onto SLN surfaces caused the production of higher amounts of α crystals accompanied by delayed crystallization onset which contributed to the reduction of particle size, interfacial tension and oil wetting ability. The W/O emulsions with higher rigidity and physical stability can be obtained by varying surfactant types and by increasing SLN mass ratios to 60%, whereby more SLNs are adsorbed at the droplet surface as a Pickering stabilizer. This study provides useful insights for the development of diacylglycerol-based SLNs and Pickering W/O emulsions which have great potential for food, cosmetic and pharmaceutical applications.
- Published
- 2021
17. Cocoa Butter Alternatives from Enzymatic Interesterification of Palm Kernel Stearin, Coconut Oil, and Fully Hydrogenated Palm Stearin Blends
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Chin Ping Tan, Pimwalan Ornla-ied, Yong Wang, and Sopark Sonwai
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chemistry.chemical_compound ,food.ingredient ,food ,chemistry ,Palm kernel ,General Chemical Engineering ,Organic Chemistry ,Coconut oil ,Structured lipid ,Stearin ,Food science ,Enzymatic interesterification ,Palm stearin - Published
- 2020
18. Current technology development for CO2 utilization into solar fuels and chemicals: A review
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Bachirou Guene Lougou, Zhijiang Wang, Yong Shuai, Azeem Mustafa, and He-Ping Tan
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business.industry ,Global warming ,Fossil fuel ,Energy Engineering and Power Technology ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Methane ,0104 chemical sciences ,Renewable energy ,chemistry.chemical_compound ,Fuel Technology ,chemistry ,Greenhouse gas ,Electrochemistry ,Environmental science ,Current technology ,0210 nano-technology ,Process engineering ,business ,Operating cost ,Energy (miscellaneous) ,Syngas - Abstract
The continuous consumption of fossil fuels causes two important impediments including emission of large concentrations of CO2 resulting in global warming and alarming utilization of energy assets. The conversion of greenhouse gas CO2 into solar fuels can be an expedient accomplishment for the solution of both problems, all together. CO2 reutilization into valuable fuels and chemicals is a great challenge of the current century. Owing to limitations in traditional approaches, there have been developed many novel technologies such as photochemical, biochemical, electrochemical, plasma-chemical and solar thermochemical. They are currently being used for CO2 capture, sequestration, and utilization to transform CO2 into valuable products such as syngas, methane, methanol, formic acid, as well as fossil fuel consumption reduction. This review summarizes different traditional and novel thermal technologies used in CO2 conversion with detailed information about their working principle, types, currently adopted methods, developments, conversion rates, products formed, catalysts and operating conditions. Moreover, a comparison of these novel technologies in terms of distinctive key features such as conversion rate, yield, use of earth metals, renewable energy, investment, and operating cost has been provided in order to have a useful review for future research direction.
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- 2020
19. A density functional theory study of metalloporphyrin derivatives act as fluorescent sensor for rapid evaluation of trimethylamine
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Xingyi Huang, Quansheng Chen, Kaiqi Liu, Haiyang Gu, Chin Ping Tan, and Yanhui Sun
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chemistry.chemical_compound ,Materials science ,chemistry ,Trimethylamine ,General Materials Science ,Density functional theory ,Fluorescence ,Combinatorial chemistry - Abstract
A fluorescent sensor based on metalloporphyrin was developed for trimethylamine (TMA) evaluation. Density functional theory (DFT) has been performed to investigate the design mechanism of fluorescent sensor. Fourteen metalloporphyrin (MP) models were selected to find the influence of metal atoms and substituent groups on the binding performance of fluorescent sensor. The optimized geometry structures, relative energies, mulliken charges, spin densities, and four frontier molecular orbitals together with binding energies of these fluorescent sensors were investigated. AgP sensor has the lowest relative energies before and after exposure to TMA, which make AgP sensor better than the others to go through more than one pathway. Binding energy results revealed that the metalloporphyrin sensors with different metal atoms and substituent groups cause remarkable changes in TMA binding performances. Thus, theoretical investigations can be used to extend the fluorescent sensor in to TMA related analytes in different detection requirements, and perhaps other molecule.
- Published
- 2020
20. Effects of spray-, oven-, and freeze drying on the physicochemical properties of poorly aqueous-soluble xanthone encapsulated by coacervation: A comparative study
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Li Yoke Ho, Yau Yan Lim, Chin Ping Tan, and Lee Fong Siow
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Coacervate ,Chromatography ,Aqueous solution ,General Chemical Engineering ,04 agricultural and veterinary sciences ,02 engineering and technology ,complex mixtures ,040401 food science ,Bioactive compound ,chemistry.chemical_compound ,Freeze-drying ,0404 agricultural biotechnology ,020401 chemical engineering ,chemistry ,Xanthone ,Aqueous solubility ,0204 chemical engineering ,Physical and Theoretical Chemistry - Abstract
This study aims to compare the effect of different drying techniques (oven-, spray-, and freeze drying) on xanthone, a poorly aqueous-soluble bioactive compound, encapsulated by coacervation using ...
- Published
- 2020
21. Recoding the Cancer Epigenome by Intervening in Metabolism and Iron Homeostasis with Mitochondria‐Targeted Rhenium(I) Complexes
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Hang Zhang, Liang Hao, Lu-Si Rao, Cai-Ping Tan, Zheng-Yin Pan, Zong-Wan Mao, Yue Zheng, and Liang-Nian Ji
- Subjects
Epigenomics ,Iron ,Drug Evaluation, Preclinical ,Receptors, Antigen, T-Cell ,Apoptosis ,Mitochondrion ,Iron Chelating Agents ,010402 general chemistry ,Methylation ,01 natural sciences ,Catalysis ,Histones ,Mice ,chemistry.chemical_compound ,Coordination Complexes ,Cell Line, Tumor ,Neoplasms ,Animals ,Humans ,Epigenetics ,biology ,010405 organic chemistry ,Chemistry ,RNA ,General Medicine ,General Chemistry ,Epigenome ,Mitochondria ,0104 chemical sciences ,Cell biology ,Deferasirox ,Rhenium ,Histone ,Cancer cell ,biology.protein ,RNA Polymerase II ,Reactive Oxygen Species ,DNA ,Signal Transduction - Abstract
The development and malignancy of cancer cells are closely related to the changes of the epigenome. In this work, a mitochondria-targeted rhenium(I) complex (DFX-Re3), integrating the clinical iron chelating agent deferasirox (DFX), has been designed. By relocating iron to the mitochondria and changing the key metabolic species related to epigenetic modifications, DFX-Re3 can elevate the methylation levels of histone, DNA, and RNA. As a consequence, DFX-Re3 affects the events related to apoptosis, RNA polymerases, and T-cell receptor signaling pathways. Finally, it is shown that DFX-Re3 induces immunogenic apoptotic cell death and exhibits potent antitumor activity in vivo. This study provides a new approach for the design of novel epigenetic drugs that can recode the cancer epigenome by intervening in mitochondrial metabolism and iron homeostasis.
- Published
- 2020
22. The influence of different metal atoms on the performance of metalloporphyrin-based sensor reaction with propanol
- Author
-
Haiyang Gu, Xingyi Huang, Quansheng Chen, Chin Ping Tan, and Yanhui Sun
- Subjects
Materials science ,Mechanical Engineering ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,Propanol ,Metal ,chemistry.chemical_compound ,chemistry ,Mechanics of Materials ,visual_art ,visual_art.visual_art_medium ,Physical chemistry ,General Materials Science ,Density functional theory ,0210 nano-technology - Abstract
Density functional theory (DFT) method was carried out to investigate the molecular interaction between metalloporphyrin-based sensor and propanol. The relative energies were used to determine the ...
- Published
- 2020
23. Understanding of the Role of Pretreatment Methods on Rapeseed Oil from the Perspective of Phenolic Compounds
- Author
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Chin Ping Tan, Liyang Yuan, Nanxi Shu, Xiaoyu Yang, Yuanfa Liu, Song Junge, Yong-Jiang Xu, and Fan Jiang
- Subjects
0106 biological sciences ,Hot Temperature ,Antioxidant ,Rapeseed ,DPPH ,medicine.medical_treatment ,01 natural sciences ,Antioxidants ,Superoxide dismutase ,chemistry.chemical_compound ,Phenols ,Tandem Mass Spectrometry ,medicine ,Humans ,Food science ,Microwaves ,Chromatography, High Pressure Liquid ,chemistry.chemical_classification ,Reactive oxygen species ,biology ,Canolol ,Chemistry ,Brassica napus ,010401 analytical chemistry ,Extraction (chemistry) ,Hep G2 Cells ,General Chemistry ,0104 chemical sciences ,Oleic acid ,Seeds ,biology.protein ,Rapeseed Oil ,General Agricultural and Biological Sciences ,Chromatography, Liquid ,010606 plant biology & botany - Abstract
The thermal pretreatment of oilseed prior to oil extraction could increase the oil yield and improve the oil quality. Phenolic compounds are important antioxidants in rapeseed oil. In this study, we investigated the impact of thermal pretreatment method on the rapeseed oil based on phenolic compound levels. Liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) analysis showed that the phenolic compound contents in the microwave-pretreated oil were higher than those in the oven- and infrared-treated oils. Sinapic acid (SA) and canolol (CA), which are the top two phenolic compounds in rapeseed oil, exerted well 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity with IC50 values of 8.45 and 8.80 μmol/L. The cell experiment uncovered that SA and CA have significant biological activities related to rapeseed oil quality, including increase of antioxidant enzymes superoxide dismutase (SOD), alleviation of reactive oxygen species (ROS), and cytotoxicity of HepG2 cells after the intake of excessive oleic acid. Further investigation indicated that SA and CA reduced cell apoptosis rate through Bax-Bcl-2-caspase-3 and p53-Bax-Bcl-2-caspase-3, respectively. Taken together, our findings suggest that microwave pretreatment is the best method to improve the content of phenolic compounds in rapeseed oil compared with oven and infrared pretreatments.
- Published
- 2020
24. Highly stereoselective construction of polycyclic benzofused tropane scaffolds and their latent bioactivities: bifunctional phosphonium salt-enabled cyclodearomatization process
- Author
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Kai Xiao, Tian Li Wang, Xiaojie Li, Lixiang Zhu, Yuan Chen, Chunhui Jiang, Jian-Ping Tan, and Xianle Rong
- Subjects
Reaction conditions ,010405 organic chemistry ,Phosphonium salt ,Tropane ,General Chemistry ,010402 general chemistry ,01 natural sciences ,Combinatorial chemistry ,0104 chemical sciences ,Stereocenter ,Catalysis ,chemistry.chemical_compound ,chemistry ,Stereoselectivity ,Phosphonium ,Bifunctional - Abstract
Structurally fused heterocycles encompassing a centerpiece of benzotropane are significant scaffolds with a plethora of promising biological activities, but such molecular architectures pose a long-standing daunting synthetic challenge. Herein, we reported a highly efficient asymmetric cyclodearomatization of 2-nitrobenzofurans with cyclic azomethine ylides by employing bifunctional phosphonium salts as phase-transfer catalysts. Under optimized reaction conditions, a diverse array of polycyclic benzofused tropane derivatives with four contiguous 4°/3° stereocenters were readily synthesized in both high yields and diastereoselectivities with up to >99% ee. The practicality and utility of this protocol were further demonstrated by the scaled-up reaction and facile elaborations. Moreover, preliminary investigations into their antitumor activities were also presented.
- Published
- 2020
25. Influence of Soya Lecithin, Sorbitan and Glyceryl Monostearate on Physicochemical Properties of Organogels
- Author
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Chin Ping Tan, Lee Fong Siow, Sheah Yee Ghan, Yin Yin Thoo, and Kok Whye Cheong
- Subjects
Polarized light microscopy ,Hydrogen bond ,Biophysics ,Bioengineering ,Sorbitan ,Applied Microbiology and Biotechnology ,Analytical Chemistry ,law.invention ,chemistry.chemical_compound ,symbols.namesake ,chemistry ,Chemical engineering ,law ,Sorbitan monostearate ,symbols ,Thermal stability ,Fourier transform infrared spectroscopy ,van der Waals force ,Crystallization ,Food Science - Abstract
The objective of this study is to investigate the effects of three different organogelators, sorbitan monostearate (SMS), soya lecithin (SL) and glyceryl monostearate (GMS) prepared at different concentrations (12%, 15% and 18%, w/w) on the structural, thermal and mechanical properties of palm olein (PO)-based organogels. Polarized light microscopy analysis revealed needle-like crystals in SMS-PO, rod-shaped tubules in SL-PO and rosette-like aggregates in GMS-PO organogels. Intermolecular hydrogen bonding and van der Waals forces were the main drivers for the self-aggregation of these organogelators in PO, as observed in Fourier transform infrared (FTIR) spectroscopy. X-ray diffraction (XRD) results indicated β’-type polymorphic structure in SL-PO and GMS-PO. As the concentration of organogelators increased, there was a corresponding increase in the firmness, gel-sol transition (Tgs) and melting temperatures of the organogels. SMS-PO with amorphous structure had the lowest firmness, thus produced weaker gel with lower thermal stability. The oil binding capacity (OBC) of both SL-PO and GMS-PO were over 90%, significantly higher than that of SMS-PO organogels. These findings indicate that crystallization is the key determinant factor to the final properties of the organogel networks. This is influenced by the molecular structure and the concentration of the organogelators used.
- Published
- 2020
26. A Theoretical Study of Metalloporphyrin-Based Fluorescent Array Sensor using Density Functional Theory
- Author
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Yanhui Sun, Chin Ping Tan, Quansheng Chen, Xingyi Huang, and Haiyang Gu
- Subjects
Sociology and Political Science ,010405 organic chemistry ,Chemistry ,Clinical Biochemistry ,Binding energy ,Trimethylamine ,010402 general chemistry ,01 natural sciences ,Biochemistry ,Fluorescence ,Porphyrin ,0104 chemical sciences ,Metal ,Clinical Psychology ,chemistry.chemical_compound ,visual_art ,Atom ,visual_art.visual_art_medium ,Physical chemistry ,Density functional theory ,Molecular orbital ,Law ,Spectroscopy ,Social Sciences (miscellaneous) - Abstract
The influences of metal atoms on optimized geometry structures, relative energies, frontline molecular orbitals, and binding energies of metalloporphyrin-based fluorescent array sensor were systematically investigated by density functional theory (DFT) at B3LYP/LAN2DZ level. DFT calculated results reveal that the selected metal atoms in the center of the metalloporphyrin plane provide difference performances of metalloporphyrin-based fluorescent array sensor for the rapid determination of trimethylamine. The calculated binding energies have displayed in the following order at the most stable states: zinc porphyrin (ZnP)
- Published
- 2020
27. Highly Enantioselective Construction of Fully Substituted Stereocenters Enabled by In Situ Phosphonium-Containing Organocatalysis
- Author
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Chunhui Jiang, Jian-Ping Tan, Hui-Lin Hu, Hongkui Zhang, Hong-Su Zhang, Xiaoyu Ren, Tian Li Wang, and Yayun Chen
- Subjects
Reaction mechanism ,010405 organic chemistry ,Enantioselective synthesis ,General Chemistry ,010402 general chemistry ,01 natural sciences ,Combinatorial chemistry ,Catalysis ,0104 chemical sciences ,Stereocenter ,chemistry.chemical_compound ,chemistry ,Organocatalysis ,Phosphonium ,Brønsted–Lowry acid–base theory ,Bifunctional - Abstract
We present, herein, an important and practical class of bifunctional in situ phosphonium-containing organocatalysis and its initial application in highly efficient and enantioselective construction...
- Published
- 2020
28. Asymmetric Construction of Bispiro‐Cyclopropane‐Pyrazolones via a [2+1] Cyclization Reaction by Dipeptide‐Based Phosphonium Salt Catalysis
- Author
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Jia-Hong Wu, Jian-Ping Tan, Dongming Lu, Xin Liu, Xiaojun Yu, Song Zhang, and Tian Li Wang
- Subjects
chemistry.chemical_compound ,Dipeptide ,chemistry ,Enantioselective synthesis ,Pyrazolones ,Phosphonium salt ,General Chemistry ,Medicinal chemistry ,Catalysis ,Cyclopropane - Published
- 2020
29. Effectiveness of fouling mechanism for bacterial immobilization in polyvinylidene fluoride membranes for biohydrogen fermentation
- Author
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Peer Mohamed Abdul, Chin Boon Ong, Nurul Sakinah Engliman, Jian Ping Tan, Tang Pei Ling, and Jamaliah Md Jahim
- Subjects
0106 biological sciences ,biology ,Fouling ,General Chemical Engineering ,04 agricultural and veterinary sciences ,biology.organism_classification ,040401 food science ,01 natural sciences ,Biochemistry ,Polyvinylidene fluoride ,chemistry.chemical_compound ,0404 agricultural biotechnology ,Adsorption ,Membrane ,chemistry ,Chemical engineering ,010608 biotechnology ,Biohydrogen ,Fermentation ,Bacteria ,Food Science ,Biotechnology ,Hydrogen production - Abstract
Bacterial immobilization was successfully develop using the fouling mechanism on the modified polyvinylidene fluoride membrane surface. The immobilization of bacteria via this method was accomplished through adsorption and entrapment of the bacteria in/on the membrane surface through fouling mechanism. Previously, the membrane was modified by polymerization method to impregnate the iron nanoparticles on the membrane surface in order to increase the surface roughness. The presence of both organic substances and bacterial cells leads to ‘combine fouling’ as the organic substances covalently bind the bacterial cells to the membrane by cross-linking, thus promote the efficiency of bacterial immobilization. The immobilized membrane was used for biohydrogen production via anaerobic fermentation using glucose-based media and it was found that it was capable of augmenting the yield of hydrogen production by 22% relative to the suspended system. This is attributed to the presence of iron on the membrane surfaces which come from the polymerization process that supplies the iron necessary for activating the hydrogenase enzyme in the bacteria, and hence, increase the production of biohydrogen. The metabolites analysis has indicated that the hydrogen production followed the acetic acid pathway.
- Published
- 2020
30. Multiple crystallization as a potential strategy for efficient recovery of succinic acid following fermentation with immobilized cells
- Author
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Siti Syazwani Mohd Shah, Abdullah Amru Indera Luthfi, Jian Ping Tan, Safa Senan Mahmod, Nur Fatin Ajeera Mohd Isa, Jamaliah Md Jahim, and Nurul Adela Bukhari
- Subjects
0106 biological sciences ,Recrystallization (geology) ,Proton Magnetic Resonance Spectroscopy ,Succinic Acid ,Bioengineering ,Crystallography, X-Ray ,01 natural sciences ,law.invention ,chemistry.chemical_compound ,Bioreactors ,Adsorption ,law ,010608 biotechnology ,Crystallization ,biology ,010405 organic chemistry ,Total recovery ,General Medicine ,Cells, Immobilized ,biology.organism_classification ,Culture Media ,0104 chemical sciences ,Actinobacillus succinogenes ,chemistry ,Succinic acid ,Fermentation ,Microscopy, Electron, Scanning ,Industrial and production engineering ,Biotechnology ,Nuclear chemistry - Abstract
This study aimed to enhance the crystallizability of bio-based succinic acid for its efficient recovery while maintaining the end product at the highest purity. Immobilization of Actinobacillus succinogenes was initially evaluated based on three different carriers: volcanic glass, clay pebbles, and silica particles. The adsorption capacity of metabolites with a low concentration (10 g/L) and a high concentration (40 g/L) was investigated. It was demonstrated that clay pebbles adsorbed the least succinic acid (
- Published
- 2020
31. In-vitro bioaccessibility of spray dried refined kenaf (Hibiscus cannabinus) seed oil applied in coffee drink
- Author
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Choon-Hui Tan, Sook Chin Chew, Kar Lin Nyam, and Chin Ping Tan
- Subjects
0303 health sciences ,food.ingredient ,ABTS ,biology ,030309 nutrition & dietetics ,DPPH ,Phytosterol ,04 agricultural and veterinary sciences ,biology.organism_classification ,Hibiscus ,040401 food science ,Kenaf ,03 medical and health sciences ,chemistry.chemical_compound ,0404 agricultural biotechnology ,food ,chemistry ,Gum arabic ,Food science ,Tocotrienol ,Tocopherol ,Food Science - Abstract
This study aimed to investigate the effect of a coffee beverage matrix on the oil release percentage and bioaccessibility of bioactive compounds from microencapsulated refined kenaf seed oil (MRKSO) using an in vitro gastrointestinal digestion model. Refined kenaf seed oil was spray-dried with gum arabic, β-cyclodextrin, and sodium caseinate. Oil release percentage, total phenolic content, radical scavenging activity of DPPH and ABTS, tocopherol and tocotrienol contents, as well as phytosterol content, were measured in the oil released from digested MRKSO along with the coffee matrix and compared to the digested MRKSO without coffee matrix and undigested MRKSO. Refined kenaf seed oil showed a significantly higher oxidative stability index than crude, degummed, and neutralized oil samples. About 91.2 and 94.7% of the oils were released from the digested MRKSO without and with coffee matrix, respectively. Oil released from the digested MRKSO with coffee matrix showed an increase in the total phenolic content (200.5%), DPPH (172.7%), and ABTS (68.1%) values, tocopherol and tocotrienol contents (24.6%), as well as the phytosterol content (62.0%), compared to oil released from the digested MRKSO without coffee matrix. MRKSO was successfully incorporated in the coffee drink and can use as a partial replacement for coffee creamers or supplementation in coffee drinks.
- Published
- 2020
32. Humulene Diepoxides from the Australian Arid Zone Herb Dysphania : Assignment of Aged Hops Constituents
- Author
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Paul V. Bernhardt, Julian Hofmann, Glen M. Boyle, Craig M. Williams, Kylie A. Agnew‐Francis, Andrei I. Savchenko, James A. Fraser, Yuen Ping Tan, Thomas H. Shellhammer, and Scott R. Lafontaine
- Subjects
Antifungal ,Phytochemistry ,food.ingredient ,Humulene ,biology ,010405 organic chemistry ,Stereochemistry ,Dysphania ,medicine.drug_class ,Organic Chemistry ,Diastereomer ,General Chemistry ,010402 general chemistry ,biology.organism_classification ,01 natural sciences ,Catalysis ,0104 chemical sciences ,chemistry.chemical_compound ,food ,chemistry ,Herb ,medicine ,Arid zone - Abstract
Dysphania is an abundant genus of plants, many of which are endemic to the Australian continent, occurring primarily in arid and temperate zones. Despite their prevalence, very few investigations into the phytochemistry of native Dysphania have been undertaken. Described herein, is the isolation and elucidation of two enantiomeric diastereomers of humulene diepoxide C from D. kalpari and D. rhadinostachya, of which unassigned diastereomers of humulene diepoxide C have been previously reported as components in beer brewed from aged hops. In addition, two (+)-humulene diepoxiols (humulene diepoxiol C-I and C-II) were isolated from D. rhadinostachya. Analysis of Chinook hops oil confirmed the presence of both humulene diepoxide C-I and C-II as trace components, and in turn enabled GC-MS peak assignment to the relative stereochemistry. Anticancer assays did not reveal any significant activity for the (+)-humulene diepoxides. Antifungal assays showed good activity against a drug-resistant strain of C. auris, with MIC50 values of 8.53 and 4.91 μm obtained for (+)-humulene diepoxide C-I and C-II, respectively.
- Published
- 2020
33. Mitochondria-targeting monofunctional platinum(<scp>ii</scp>)–lonidamine conjugates for cancer cell de-energization
- Author
-
Cai-Ping Tan, Zheng-Yin Pan, Liang-Nian Ji, Nafees Muhammad, Jie Wang, Zong-Wan Mao, Muhammad Kamran, and Nasreen Sadia
- Subjects
Cisplatin ,0303 health sciences ,Hexokinase ,biology ,DNA damage ,Cytochrome c ,Lonidamine ,Mitochondrion ,Inorganic Chemistry ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,chemistry ,Apoptosis ,030220 oncology & carcinogenesis ,Cancer cell ,biology.protein ,medicine ,Cancer research ,030304 developmental biology ,medicine.drug - Abstract
Monofunctional Pt(II) complexes represent a class of antitumor agents that may expand the antitumor spectrum and overcome the drug resistance of the clinically used cisplatin and its derivatives. Herein, we designed three novel monofunctional Pt(II) complexes, namely, MPL-I, MPL-II and MPL-III, by anchoring lonidamine (an inhibitor of mitochondrial hexokinase) to the Pt(II) centre for the selective de-energization of cancer cells. Among them, MPL-III is more potent than cisplatin against triple negative breast cancer MDA-MB-231 cells and exhibits relatively lower cytotoxicity on breast epithelial cells. Intracellular distribution studies reveal that MPL-III mainly accumulates in the mitochondria. Furthermore, MPL-III induces detrimental changes in the mitochondrial ultrastructure and significant loss of the mitochondrial membrane potential, inhibits glycolysis and disrupts mitochondrial respiration. As a consequence, MPL-III causes cell cycle arrest in the G0/G1 phase, and mitochondria-mediated apoptosis involving caspase activation and cytochrome c release. RNA-sequencing data show that MPL-III perturbs the pathways including DNA damage, metabolic process and transcription regulator activity. Our research provides an in-depth study and a new design strategy for effective mono-functional platinum complexes with action mechanisms distinct from those of the clinical platinum-based anticancer drugs.
- Published
- 2020
34. Chemical Composition, Oxidative Stability, and Antioxidant Activity of Allium ampeloprasum L. (Wild Leek) Seed Oil
- Author
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Umer Rashid, Saud I. Al-Resayes, Fahad A. Al-Misned, Hassen Mohamed Sbihi, Hamed A. El-Serehy, Imededdine Arbi Nehdi, and Chin Ping Tan
- Subjects
Antioxidant ,030309 nutrition & dietetics ,General Chemical Engineering ,medicine.medical_treatment ,Linoleic acid ,Flavonoid ,Palmitic acid ,03 medical and health sciences ,chemistry.chemical_compound ,0404 agricultural biotechnology ,Allium ampeloprasum ,medicine ,Food science ,Chemical composition ,chemistry.chemical_classification ,0303 health sciences ,ABTS ,biology ,food and beverages ,04 agricultural and veterinary sciences ,General Medicine ,General Chemistry ,biology.organism_classification ,040401 food science ,Oleic acid ,chemistry - Abstract
Allium ampeloprasum L., commonly known as wild leek, is an edible vegetable that has been cultivated for centuries. However, no detailed studies have been undertaken to valorize A. ampeloprasum seed oil. This study aims to evaluate the physicochemical properties, chemical composition, and antioxidant activity of A. ampeloprasum seed oil. The seed oil content was found to be 18.20%. Gas chromatographymass spectrometry (GC-MS) showed that linoleic acid (71.65%) was the dominant acid, followed by oleic acid (14.11%) and palmitic acid (7.11%). A. ampeloprasum seed oil exhibited an oxidative stability of 5.22 h. Moreover, γ- and δ-tocotrienols were the major tocols present (79.56 and 52.08 mg/100 g oil, respectively). The total flavonoid content (16.64 µg CE /g oil) and total phenolic content (62.96 µg GAE /g oil) of the seed oil were also determined. The antioxidant capacity of the oil, as evaluated using the ABTS assay (136.30 µM TEAC/g oil), was found to be significant. These findings indicate that A. ampeloprasum seeds can be regarded as a new source of edible oil having health benefits and nutritional properties.
- Published
- 2020
35. A transition-metal-free multicomponent reaction towards constructing chiral 2H-1,4-benzoxazine scaffolds
- Author
-
Juan Du, Lixiang Zhu, Jianke Pan, Jia-Hong Wu, Tian Li Wang, Jian-Ping Tan, Xiaoyu Ren, and Jixing Che
- Subjects
chemistry.chemical_compound ,Dipeptide ,Cascade reaction ,Transition metal ,Chemistry ,Environmental Chemistry ,Phosphonium salt ,Pollution ,Asymmetric induction ,Combinatorial chemistry ,Catalysis ,Stereocenter - Abstract
Herein, a transition-metal-free multicomponent cascade reaction of readily available α-halogenated ketones, ortho-aminophenols, and aldehydes using a novel dipeptide-based phosphonium salt catalyst was developed for the efficient construction of various 2H-1,4-benzoxazine derivatives with excellent functional-group tolerance. The method represents an unprecedented approach for trapping active 1,5-bifunctional intermediates with α-halogenated ketones to access biologically important benzoxazine scaffolds bearing two stereogenic centers with excellent asymmetric induction.
- Published
- 2020
36. Enantioselective Construction of Spiro[chroman‐thiazolones]: Bifunctional Phosphonium Salt‐Catalyzed [2+4] Annulation between 5‐Alkenyl Thiazolones and ortho ‐Hydroxyphenyl‐Substituted para‐ Quinone Methides
- Author
-
Zhiyu Jiang, Yuan Chen, Jian-Ping Tan, Hongkui Zhang, Xiaoyu Ren, Tian Li Wang, and Chunhui Jiang
- Subjects
chemistry.chemical_compound ,Annulation ,Chemistry ,Enantioselective synthesis ,Phosphonium salt ,Para-quinone ,General Chemistry ,Bifunctional ,Medicinal chemistry ,Catalysis - Published
- 2019
37. Deep-frying oil induces cytotoxicity, inflammation and apoptosis on intestinal epithelial cells
- Author
-
Chin Ping Tan, Yong-Jiang Xu, Xue Li, Bin-bin Nian, and Yuanfa Liu
- Subjects
Hot Temperature ,Inflammation ,Apoptosis ,Flow cytometry ,chemistry.chemical_compound ,medicine ,Cytotoxic T cell ,Humans ,Plant Oils ,Cooking ,Cytotoxicity ,Triglycerides ,Nutrition and Dietetics ,medicine.diagnostic_test ,Triglyceride ,Chemistry ,Inflammatory Bowel Diseases ,CXCL1 ,Real-time polymerase chain reaction ,Biochemistry ,medicine.symptom ,Caco-2 Cells ,Agronomy and Crop Science ,Oils ,Food Science ,Biotechnology - Abstract
Deep-frying oil has been found to cause inflammatory bowel disease (IBD). However, the molecular mechanism of the effect of deep-frying palm oil on IBD still remains undetermined.In the present study, bioinformatics and cell biology were used to investigate the functions and signal pathway enrichments of differentially expressed genes. The bioinformatics analysis of three original microarray datasets (GSE73661, GSE75214 and GSE126124) in the NCBI-Gene Expression Omnibus database showed 17 down-regulated genes (logFC 0) and 2 up-regulated genes (logFC 0) existed in the enteritis tissue. Meanwhile, pathway enrichment and protein-protein interaction network analysis suggested that IBD is relevant to cytotoxicity, inflammation and apoptosis. Furthermore, Caco-2 cells were treated with the main oxidation products of deep-frying oil-total polar compounds (TPC) and its components (polymerized triglyceride, oxidized triglycerides and triglyceride degradation products) isolated from deep-frying oil. The flow cytometry experiment revealed that TPC and its components could induce apoptosis, especially for oxidized triglyceride. A quantitative polymerase chain reaction analysis demonstrated that TPC and its component could induce Caco-2 cell apoptosis through AQP8/CXCL1/TNIP3/IL-1.The present study provides fundamental knowledge for understanding the effects of deep-frying oils on the cytotoxic and inflammatory of Caco-2 cells, in addition to clarifying the molecular function mechanism of deep-frying oil in IBD. © 2021 Society of Chemical Industry.
- Published
- 2021
38. Palm oil supply chain factors impacting chlorinated precursors of 3-MCPD esters
- Author
-
David Ross Appleton, Norliza Saparin, Mohd Zairey Bin Md. Zain, Maizatul Putri Ahmad Sabri, See Siang Cheah, Huey Fang Teh, Anusha Nair, Nur Azwani Ab Karim, Oi Ming Lai, Soon Huat Tiong, Siti Aishah Abd Wahid, Chin Ping Tan, and Ahmad Sarwani Adni
- Subjects
congenital, hereditary, and neonatal diseases and abnormalities ,Halogenation ,Health, Toxicology and Mutagenesis ,education ,alpha-Chlorohydrin ,Food Contamination ,Palm Oil ,Toxicology ,complex mixtures ,Food Supply ,chemistry.chemical_compound ,3-MCPD ,Palm oil ,Hydrocarbons, Chlorinated ,Water washing ,Refining (metallurgy) ,Chemistry ,Public Health, Environmental and Occupational Health ,food and beverages ,Esters ,General Chemistry ,General Medicine ,Pulp and paper industry ,Crude oil ,body regions ,Palm ,Palm fruit ,Food Analysis ,Food Science - Abstract
Chlorinated compounds such as sphingolipid-based organochlorine compounds are precursors for the formation of 3-monochlororopanediol (3-MCPD) esters in palm oil. This study evaluates the effects of several factors within the palm oil supply chain on the levels of sphingolipid-based organochlorine, which in turn may influence the formation of 3-MCPD esters during refining. These factors include application of inorganic chlorinated fertiliser in the oil palm plantation, bruising and degradation of oil palm fruits after harvest, recycling of steriliser condensate as water for dilution of crude oil during oil palm milling, water washing of palm oil and different refining conditions. It was observed that bruised and degraded oil palm fruits showed higher content of sphingolipid-based organochlorine than control. In addition, recycling steriliser condensate during milling resulted in elevated content of sphingolipid-based organochlorine in palm oil. However, the content of sphingolipid-based organochlorine compounds was reduced by neutralisation, degumming and bleaching steps during refining. Although water washing of crude palm oils (CPO) prior to refining did not reduce the content of sphingolipid-based organochlorine, it did reduce the formation of 3-MCPD esters through the removal of water-soluble chlorinated compounds. It was found that the use of inorganic chlorinated fertiliser in plantations did not increase the content of chlorinated compounds in oil palm fruits and extracted oil, and hence chlorinated fertiliser does not seem to play a role in the formation of 3-MCPD esters in palm oil. Overall, this study concluded that lack of freshness and damage to the fruits during transport to mills, combined with water and oil recycling in mills are the major contributors of chlorinated precursor for 3-MCPD esters formation in palm oil.
- Published
- 2021
39. Induction and Monitoring of DNA Phase Separation in Living Cells by a Light-Switching Ruthenium Complex
- Author
-
Cai-Ping Tan, Yu-Jian Wang, Yuebin Zhang, Guohui Li, Wen-Jin Wang, Zong-Wan Mao, and Xia Mu
- Subjects
Light ,chemistry.chemical_element ,Molecular Dynamics Simulation ,Ligands ,Biochemistry ,Catalysis ,Ruthenium ,Transcriptome ,Molecular dynamics ,chemistry.chemical_compound ,Colloid and Surface Chemistry ,Coordination Complexes ,Gene expression ,Molecule ,Humans ,Molecular Structure ,Chemistry ,General Chemistry ,DNA ,In vitro ,Chromatin ,A549 Cells ,Biophysics - Abstract
Phase separation of DNA is involved in chromatin packing for the regulation of gene transcription. Visualization and manipulation of DNA phase separation in living cells present great challenges. Herein, we present a Ru(II) complex (Ru1) with high DNA binding affinity and DNA "light-switch" behavior that can induce and monitor DNA phase separation both in vitro and in living cells. Molecular dynamics simulations indicate that the two phen-PPh3 ligands with positively charged lipophilic triphenylphosphine substituents and flexible long alkyl chains in Ru1 play essential roles in the formation of multivalent binding forces between DNA molecules to induce DNA phase separation. Importantly, the unique environmental sensitive emission property of Ru1 enables direct visualization of the dynamic process of DNA phase separation in living cells by two-photon phosphorescent lifetime imaging. Moreover, Ru1 can change the gene expression pattern by modulating chromatin accessibility as demonstrated by integrating RNA-sequencing and transposase-accessible chromatin with high-throughput sequencing. In all, we present here the first small-molecule-based tracer and modulator of DNA phase separation in living cells and elucidate its impact on the chromatin state and transcriptome.
- Published
- 2021
40. Polycarbonate : antimicrobial polymer delivery, monomer synthesis, rapid polymerization and functionalization
- Author
-
Eddy Wei Ping Tan
- Subjects
chemistry.chemical_compound ,Materials science ,Monomer ,Polymerization ,chemistry ,Antimicrobial polymer ,visual_art ,Polymer chemistry ,visual_art.visual_art_medium ,Surface modification ,Polycarbonate - Published
- 2021
41. W/O high internal phase emulsion featuring by interfacial crystallization of diacylglycerol and different internal compositions
- Author
-
Yong Wang, Chaoying Qiu, Oi Ming Lai, Liu Yingwei, Wan Jun Lee, and Chin Ping Tan
- Subjects
Materials science ,Water ,General Medicine ,beta Carotene ,Controlled release ,Internal phase ,Analytical Chemistry ,law.invention ,Surface tension ,Diglycerides ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,law ,Polyglycerol polyricinoleate ,Emulsion ,Emulsions ,Crystallization ,Elastic modulus ,Food Science ,Diacylglycerol kinase - Abstract
High internal phase emulsions (HIPEs) show promising application in food and cosmetic industries. In this work, diacylglycerol (DAG) was applied to fabricate water-in-oil (W/O) HIPEs. DAG-based emulsion can hold 60% water and the emulsion rigidity increased with water content, indicating the water droplets acted as “active fillers”. Stable HIPE with 80% water fraction was formed through the combination of 6 wt% DAG with 1 wt% polyglycerol polyricinoleate (PGPR). The addition of 1 w% kappa (κ)-carrageenan and 0.5 M NaCl greatly reduced the droplet size and enhanced emulsion rigidity, and the interfacial tension of the internal phase was reduced. Benefiting from the Pickering crystals-stabilized interface by DAG as revealed by the microscopy and enhanced elastic modulus of emulsions with the gelation agents, the HIPEs demonstrated good retaining ability for anthocyanin and β-carotene. This study provides insights for the development of W/O HIPEs to fabricate low-calories margarines, spread or cosmetic creams.
- Published
- 2021
42. The In Vitro α-Glucosidase Inhibition Activity of Various Solvent Fractions of Tamarix dioica and 1H-NMR Based Metabolite Identification and Molecular Docking Analysis
- Author
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Muhammad Waseem Mumtaz, Syed Ali Raza, Umer Rashid, Chin Ping Tan, Aamir Niaz, Tai Boon Tan, Ahmad Adnan, and Rashida Bashir
- Subjects
antioxidant ,DPPH ,Tamarix dioica ,Flavonoid ,Ethyl acetate ,Plant Science ,Article ,03 medical and health sciences ,chemistry.chemical_compound ,0404 agricultural biotechnology ,Gallic acid ,Ecology, Evolution, Behavior and Systematics ,Isorhamnetin ,metabolites ,030304 developmental biology ,chemistry.chemical_classification ,0303 health sciences ,Chromatography ,Ecology ,1H-NMR ,Botany ,04 agricultural and veterinary sciences ,040401 food science ,chemistry ,QK1-989 ,docking ,Myricetin ,α-glucosidase ,Kaempferol ,Quercetin ,human activities - Abstract
The Tamarix dioica (T. dioica) is widely used medicinal plant to cure many chronic ailments. T. dioica is being used to manage diabetes mellitus in traditional medicinal system, however, very little scientific evidence is available on this plant in this context. The current study involves the fractionation of crude methanolic extract of T. dioica using n-hexane, ethyl acetate, chloroform, and n-butanol. The screening for antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay was carried out. The in vitro antidiabetic potential was assessed by measuring α-glucosidase inhibition. Total phenolic and flavonoid contents were also determined for each fraction. The metabolites were identified using highly sensitive and emerging 1H-NMR technique. The results revealed the ethyl acetate fraction as the most potent with DPPH scavenging activity of 84.44 ± 0.21% and α-glucosidase inhibition with IC50 value of 122.81 ± 2.05 µg/mL. The total phenolic and flavonoid content values of 205.45 ± 1.36 mg gallic acid equivalent per gram dried extract and 156.85 ± 1.33 mg quercetin equivalent per gram dried extract were obtained for ethyl acetate fraction. The bucketing of 1H-NMR spectra identified 22 metabolites including some pharmacologically important like tamarixetin, tamaridone, quercetin, rutin, apigenin, catechin, kaempferol, myricetin and isorhamnetin. Leucine, lysine, glutamic acid, aspartic acid, serine, and tyrosine were the major amino acids identified in ethyl acetate fraction. The molecular docking analysis provided significant information on the binding affinity among secondary metabolites and α-glucosidase. These metabolites were most probably responsible for the antioxidant activity and α-glucosidase inhibitory potential of ethyl acetate fraction. The study ascertained the ethnomedicinal use of T. dioica to manage diabetes mellitus and may be a helpful lead towards naturopathic mode for anti-hyperglycemia.
- Published
- 2021
- Full Text
- View/download PDF
43. Bifunctional Phosphonium Salt Directed Enantioselective Formal [4 + 1] Annulation of Hydroxyl-Substituted para-Quinone Methides with α-Halogenated Ketones
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Jia-Hong Wu, Tian Li Wang, Jian-Ping Tan, Jianke Pan, Xiaoyu Ren, Yuan Chen, Chunhui Jiang, Hong-Su Zhang, and Peiyuan Yu
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Annulation ,010405 organic chemistry ,Chemistry ,Organic Chemistry ,Enantioselective synthesis ,Phosphonium salt ,010402 general chemistry ,01 natural sciences ,Biochemistry ,Medicinal chemistry ,Cycloaddition ,Transition state ,0104 chemical sciences ,Catalysis ,chemistry.chemical_compound ,Intramolecular force ,Physical and Theoretical Chemistry ,Bifunctional - Abstract
A highly diastereo- and enantioselective [4 + 1] cycloaddition of para-quinone methides to α-halogenated ketones was realized by bifunctional phosphonium salt catalysis, furnishing functionalized 2,3-dihydrobenzofurans in high yields and excellent stereoselectivities (>20:1 dr and up to >99.9% ee). Mechanistic observations suggested that the reaction underwent a cascade intermolecular substitution/intramolecular 1,6-addition process. DFT calculations revealed the presence of multiple H-bonding interactions between the catalyst and the enolate intermediate in the stereodetermining transition states.
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- 2019
44. Effects of limited moisture content and storing temperature on retrogradation of rice starch
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Qiang Huang, Li Ding, Chin Ping Tan, Xiong Fu, and Bin Zhang
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Retrogradation (starch) ,Food Handling ,Starch ,02 engineering and technology ,Biochemistry ,03 medical and health sciences ,chemistry.chemical_compound ,Crystallinity ,Differential scanning calorimetry ,Structural Biology ,Amylose ,Transition Temperature ,Food science ,Molecular Biology ,030304 developmental biology ,0303 health sciences ,Moisture ,Temperature ,Recrystallization (metallurgy) ,Oryza ,General Medicine ,021001 nanoscience & nanotechnology ,Food Storage ,chemistry ,Amylopectin ,0210 nano-technology - Abstract
The objective of this study is to investigate the effects of limited moisture content and storing temperature on the retrogradation of rice starch. Starch was gelatinized in various moisture contents (30–42%) and rice paste was stored at different temperatures (4 °C, 15 °C, 30 °C, −18/30 °C and 4/30 °C). X-ray diffraction (XRD) analysis revealed that after retrogradation, the crystalline type of rice starch changed from A-type to B + V type. The B-type crystallinity of retrograded rice starch under 30 °C was the highest among the five temperature conditions, and an increase in B-type crystallinity with increasing moisture content was observed. Differential scanning calorimetry (DSC) results revealed that rice starch retrogradation consists of recrystallization of amylopectin and amylose, and is mainly attributed to amylopectin. The higher moisture content was favorable for amylopectin recrystallization, whereas the moisture content had little effect on the amylose recrystallization. The optimal temperature for amylopectin and amylose recrystallization was 4 °C and 15 °C, respectively. The amylopectin recrystallization enthalpy of rice starch stored at 4/30 °C was mediated between 4 °C and 30 °C but always higher than that at −18/30 °C. On the whole, after being heated at 42% moisture content and stored at 4 °C, rice starch showed the maximum total retrogradation enthalpy (8.44 J/g).
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- 2019
45. Production, safety, health effects and applications of diacylglycerol functional oil in food systems: a review
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Ying Li, Chin Ping Tan, Yong Wang, Eng Tong Phuah, Oi Ming Lai, Yee Ying Lee, Teck Kim Tang, and Ling-Zhi Cheong
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Food Safety ,Food industry ,030309 nutrition & dietetics ,Health benefits ,Industrial and Manufacturing Engineering ,Diglycerides ,03 medical and health sciences ,chemistry.chemical_compound ,0404 agricultural biotechnology ,Fat accumulation ,Functional Food ,Humans ,Food science ,Triglycerides ,Diacylglycerol kinase ,chemistry.chemical_classification ,0303 health sciences ,urogenital system ,Fat substitute ,business.industry ,Glycidol ,Fatty acid ,04 agricultural and veterinary sciences ,General Medicine ,Postprandial Period ,040401 food science ,Cholesterol ,Glucose ,chemistry ,Food systems ,lipids (amino acids, peptides, and proteins) ,Diet, Healthy ,business ,Oils ,Food Science - Abstract
Diacylglycerol (DAG) is a world leading anti-obesity functional cooking oil synthesized via structural modification of conventional fats and oils. DAG exits in three stereoisomers namely sn-1,2-DAG, sn-1,3-DAG, and sn-2,3-DAG. DAG particularly sn-1,3-DAG demonstrated to have the potential in suppressing body fat accumulation and lowering postprandial serum triacylglycerol, cholesterol and glucose level. DAG also showed to improve bone health. This is attributed to DAG structure itself that caused it to absorb and digest via different metabolic pathway than conventional fats and oils. With its purported health benefits, many studies attempt to enzymatically or chemically synthesis DAG through various routes. DAG has also received wide attention as low calorie fat substitute and has been incorporated into various food matrixes. Despite being claimed as healthy cooking oil the safety of DAG still remained uncertain. DAG was banned from sale as it was found to contain probable carcinogen glycidol fatty acid esters. The article aims to provide a comprehensive and latest review of DAG emphasizing on its structure and properties, safety and regulation, process developments, metabolism and beneficial health attributes as well as its applications in the food industry.
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- 2019
46. Comparison assessment between SIM and MRM mode in the analysis of 3-MCPD ester, 2-MCPD ester and glycidyl ester
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Yu Hua Wong, Faridah Abas, Kok Ming Goh, Chin Ping Tan, Samuel Chao Ming Yeo, May Yen Ang, and Oi Ming Lai
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Glycerol ,030309 nutrition & dietetics ,alpha-Chlorohydrin ,Food Contamination ,Mass spectrometry ,Gas Chromatography-Mass Spectrometry ,03 medical and health sciences ,chemistry.chemical_compound ,0404 agricultural biotechnology ,Limit of Detection ,Tandem Mass Spectrometry ,Selected ion monitoring ,Chocolate ,Derivatization ,Detection limit ,0303 health sciences ,Chromatography ,Selected reaction monitoring ,Reproducibility of Results ,Esters ,04 agricultural and veterinary sciences ,Repeatability ,040401 food science ,Infant Formula ,Triple quadrupole mass spectrometer ,chemistry ,Calibration ,Gas chromatography ,Food Analysis ,Food Science - Abstract
The detection of 3- and 2-MCPD ester and glycidyl ester was transformed from selected ion monitoring (SIM) mode to multiple reaction monitoring (MRM) mode by gas chromatography triple quadrupole spectrometry. The derivatization process was adapted from AOCS method Cd 29a-13. The results showed that the coefficient of determination (R2) of all detected compounds obtained from both detection mode was comparable, which falls between 0.997 and 0.999. The limit of detection and quantification (LOD and LOQ) were improved in MRM mode as compared to SIM mode. In MRM mode, the LOD of 3- and 2-MCPD ester was achieved 0.01 mg/kg while the LOQ was 0.05 mg/kg. Besides, LOD and LOQ of glycidyl ester were 0.024 and 0.06 mg/kg respectively. A blank spiked with MCPD esters (0.03, 0.10 and 0.50 mg/kg) and GE (0.06, 0.24 and 1.20 mg/kg) were chosen for repeatability and recovery tests. MRM mode showed better repeatability in area ratio and recovery with relative standard deviation (RSD %)
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- 2019
47. Facile preparation of trace-iron doped manganese oxide/N-doped ketjenblack carbon composite for efficient ORR electrocatalyst
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Guangli Li, Li Fuzhi, Chen Zhen, Ping Tan, Yuejun Liu, and Pu Shi
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Materials science ,General Chemical Engineering ,Limiting current ,chemistry.chemical_element ,02 engineering and technology ,General Chemistry ,Manganese ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Electrocatalyst ,01 natural sciences ,0104 chemical sciences ,Ferrous ,law.invention ,Catalysis ,chemistry.chemical_compound ,chemistry ,law ,Calcination ,0210 nano-technology ,Melamine ,Carbon ,Nuclear chemistry - Abstract
Low-cost and highly efficient catalysts toward oxygen reduction reaction (ORR) are extremely required for the rapid development of Al-air batteries. Herein, novel trace-iron doped manganese oxide/N-doped ketjenblack carbon composites (Fe–MnOx/N–KB) were prepared by a facie and scalable route using cheap, more abundant, and commercially available raw materials (i.e. manganese sulfate, ferrous nitrate, melamine and KB). The proposed route only consisted of one-pot hydrothermal treatment and subsequent a mild calcination process. The high spefic area and synergistic effect from Fe–N–C active sites and Mn3+ greatly boosted the ORR activity. As a result, Fe–MnOx/N–KB showed superior ORR activity in terms of positive half-wave potential (0.78 V) and high limiting current density (5.8 mA/cm2), comparable to those of commercial Pt/C (0.82 V, 5.3 mA/cm2). Moreover, Fe–MnOx/N–KB exhibited excellent catalytic stability. When used as cathode catalyst in home-made Al-air battery, Fe–MnOx/N–KB showed higher discharge voltage (1.51 V) at constant current density of 50 mA/cm2 than that of commercial Pt/C (1.46 V). Considering its low cost, high efficiency and scalable preparation, Fe–MnOx/N–KB has great potential to substitute commercial Pt/C for ORR.
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- 2019
48. Octenylsuccinate quinoa starch granule-stabilized Pickering emulsion gels: Preparation, microstructure and gelling mechanism
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Chin Ping Tan, Xiong Fu, Chao Li, Songnan Li, Qiang Huang, and Bin Zhang
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010304 chemical physics ,Chemistry ,Starch ,General Chemical Engineering ,Granule (cell biology) ,04 agricultural and veterinary sciences ,General Chemistry ,Dynamic mechanical analysis ,Apparent viscosity ,040401 food science ,01 natural sciences ,Pickering emulsion ,Contact angle ,chemistry.chemical_compound ,0404 agricultural biotechnology ,Chemical engineering ,Rheology ,0103 physical sciences ,Emulsion ,Food Science - Abstract
The development of emulsion gels has attracted increasing interests due to their potential applications as oil structuring templates and release-controlled carriers for sensitive lipid-soluble bioactive compounds. This work aimed to elucidate the importance of changing the degree of substitution (DS, 0.0072–0.0286) and oil volume fraction (Φ, 10–90%) to achieve octenylsuccinate (OS) quinoa starch granule-based Pickering emulsion gels. The gelation process, droplet size distribution, rheological properties and microstructure of Pickering emulsion gels formed at various DS and Φ values were evaluated. Octenylsuccinylation did not change the morphology or the granule size of quinoa starch but significantly increased the contact angle from 36.2° to 68.7°. OS quinoa starch granule-stabilized Pickering emulsion gels were formed at a DS of 0.0286 with Φ values ranging from 50 to 70%. At the Φ value of 70%, increasing DS progressively increased the apparent viscosity (η) and storage modulus (G′) of the emulsions as a result of the adsorption of more OS quinoa starch granules at the oil/water interface. Both η and G′ showed an increasing trend as a function of Φ (50–70%) at a DS value of 0.0286, and this was closely related to the microstructure of the formed emulsion gels. The network of OS quinoa starch-based Pickering emulsion gels at high Φ values (e.g., 60% and 70%) was mainly composed of compact “aggregated” oil droplets, which was largely attributed to the inter-droplet interactions. These results are of great help in understanding the gelling mechanism and the development of starch granule-based Pickering emulsion gels.
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- 2019
49. Electrochemical Biosensing of Chilled Seafood Freshness by Xanthine Oxidase Immobilized on Copper-Based Metal–Organic Framework Nanofiber Film
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Cai Shen, Chin Ping Tan, Oi-Ming Lai, Ling-Zhi Cheong, Zhipan Wang, and Baokai Ma
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Detection limit ,Chromatography ,fungi ,technology, industry, and agriculture ,food and beverages ,Xanthine ,Applied Microbiology and Biotechnology ,Analytical Chemistry ,chemistry.chemical_compound ,chemistry ,Linear range ,Biocatalysis ,Nanofiber ,Safety, Risk, Reliability and Quality ,Xanthine oxidase ,Safety Research ,Biosensor ,Hypoxanthine ,Food Science - Abstract
ATP degradation is an important biochemical change during decomposition of seafood. Hypoxanthine and xanthine which are formed during ATP degradation process can be used for evaluation of chilled seafood freshness. Present study successfully immobilized xanthine oxidase (XOD) onto a type of biocompatible copper-based metal organic framework nanofibers (Cu-MOF) film and used it for fabrication of a hypoxanthine and xanthine electrochemical biosensor. Cu-MOF can efficiently entrap XOD, provide a suitable atmosphere for XOD biocatalysis, and ensure good electron transfer between enzyme and electrode surface. The as-prepared XOD-electrochemical biosensor demonstrated high sensitivity for both hypoxanthine and xanthine with a wide linear range (0.01 to 10 μM) and low limit of detection. During the 3-week storage stability test at 4 °C, the fabricated biosensor demonstrated good reusability (up to 100 times) and excellent storage stability for hypoxanthine and xanthine. When applied for detection of hypoxanthine and xanthine in chilled squid and large yellow croaker, the XOD-electrochemical biosensors demonstrated good recovery rates.
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- 2019
50. Anticancer Ir III –Aspirin Conjugates for Enhanced Metabolic Immuno‐Modulation and Mitochondrial Lifetime Imaging
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Zong-Wan Mao, Dong-Yang Zhang, Yue Zheng, Hang Zhang, Fang-Xin Wang, Cai-Ping Tan, Jian-Jun Cao, Xiao-Wen Wu, and Liang-Nian Ji
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Aspirin ,010405 organic chemistry ,Chemistry ,Organic Chemistry ,Cancer ,General Chemistry ,Mitochondrion ,Pharmacology ,010402 general chemistry ,medicine.disease ,01 natural sciences ,Catalysis ,0104 chemical sciences ,Paraptosis ,chemistry.chemical_compound ,In vivo ,Apoptosis ,medicine ,Salicylic acid ,Conjugate ,medicine.drug - Abstract
The chemo-anti-inflammatory strategy is attracting ever more attention for the treatment of cancer. Here, two cyclometalated IrIII complexes Ir2 and Ir3 formed by conjugation of Ir1 with two antiphlogistics (aspirin and salicylic acid) have been designed. Ir2 and Ir3 exhibit higher antitumor and anti-inflammatory potencies than a mixture of Ir1 and aspirin/salicylic acid. We show that they can be hydrolyzed, accumulate in mitochondria, and induce mitochondrial dysfunction. Due to their intense long-lived phosphorescence, Ir2 and Ir3 can track mitochondrial morphological changes. Phosphorescence lifetime imaging shows that Ir2 and Ir3 can aggregate during mitochondrial dysfunction. As expected, Ir2 and Ir3 exhibit immunomodulatory properties by regulating the activity of immune factors. Both Ir2 and Ir3 can induce caspase-dependent apoptosis and caspase-independent paraptosis and inhibit several events related to metastasis. Moreover, Ir2 and Ir3 show potent tumor growth inhibition in vivo. Our study demonstrates that the combination of mitochondrial-targeting and immunomodulatory activities is feasible to develop multifunctional metal-based anticancer agents.
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- 2019
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