Co-reporter:Weihua Xiao, Yang Zhang, Chongxin Fan, Lujia Han
Food Chemistry 2017 Volume 214() pp:242-247
Publication Date(Web):1 January 2017
DOI:10.1016/j.foodchem.2016.07.096
•Superfine black tea powder (BTP) was prepared with medium diameter 6.9 μm.•Superfine BTP showed markedly fast infusion rates and high infusion yields.•Superfine BTP has preferable dispersion stability as compared to coarsely ground BTPs.•Homogenization and addition of stabilizers improved the dispersion properties.Tea is rich in healthy components including polyphenols, caffeine, gallic acids, and others. Current technology of tea infusion and extraction leads to more than 40% soluble solids wasted in spent leaf. To increase the bioaccessibility of black tea, we report a method of pulverization treatments including general and superfine grinding to reduce the particle size. In comparison with coarsely ground black tea powders (BTPs), the superfine ground BTP with medium diameter 6.9 μm resulted in significant higher infusion yield of total polyphenols (TPP), caffeine, and water-soluble carbohydrate (WSC). The total water-soluble solids (WSS) of superfine BTP infusion increased markedly by twice due to the accelerated diffusion and enhanced solubility. High correlation between particle size and sedimentation ratio suggested improved dispersion stability of superfine BTP. The optimal dispersion of 0.1% superfine BTP in water was obtained by combination of homogenization and 0.08% CMC-Na formulation with 27.05% centrifugal sedimentation ratio.
Co-reporter:Guanya Ji, Lujia Han, Chongfeng Gao, Weihua Xiao, Yang Zhang, Yaoyao Cao
Bioresource Technology 2017 Volume 241(Volume 241) pp:
Publication Date(Web):1 October 2017
DOI:10.1016/j.biortech.2017.05.062
•Increase of glucose yield is limited with reduction of particle size at tissue scale.•Crystallinity significantly changed with particle size decreased to cellar scale.•Significant correlations among particle size, crystalline property and glucose yield.•Quantitative analysis for particle size, crystalline property and glucose yield.Mechanical fragmentation is an important pretreatment in the biomass biotransformation process. Mechanical fragmentation at the tissue scale significantly reduced the particle size of rice straw but did not significantly change its crystalline properties; the increase in the glucose yield was limited from 28.75% (95.55 mg/g substrate) to 35.29% (115.28 mg/g substrate). Mechanical fragmentation at the cellular scale destroyed the cell wall structure and reduced its crystalline properties. Thus, the glucose yield also showed a significant increase from 35.29% (115.28 mg/g substrate) to 81.71% (287.07 mg/g of substrate). The quantitative equations among the particle size, crystalline properties and glucose yield (mg/g substrate) are as follows: CrI = 44.14 × [1−exp(−0.03658 × D50)] and CP = (8.403 × logD50−24.1836)/(1−4.225/D50^0.5); GY = −5.636CrI + 343.7 and GY = −14.62CP + 512.1; and GY = 97.218 + 247.5 × exp(−0.03824 × D50). The quantitative correlations among the mechanical fragmentation scales and crystalline properties can determine the effect and mechanism of mechanical fragmentation on biomass and can further promote the construction of a cost-competitive biotransformation process for biomass.Download high-res image (165KB)Download full-size image
Co-reporter:Xian Liu, Zhicheng Wu, Yahong Han, Lujia Han
Energy 2017 Volume 133(Volume 133) pp:
Publication Date(Web):15 August 2017
DOI:10.1016/j.energy.2017.05.083
•Cornstalk was modified by gradient-concentration alkaline and briquetted with coal.•Bonding mechanisms were explored by combined physicochemical characteristic Analysis.•The optimal fibrous constituents and performance were found in 2% alkaline treatment.•The optimal ratio of cellulose:hemicellulose:lignin was 7.0:2.5:0.5 for bonding.•Formed spatial network structure of the solid fraction mainly contributed to bonding.In this paper, corn stalk was alkalized by gradient concentrations of sodium hydroxide and briquetted with anthracite coal. The bonding mechanism was explored by a combined analysis of physicochemical, microstructure and mechanical properties. Alkaline treatment had a large effect on decomposing most of lignin and dissolving the carbohydrates in corn stalk even at a low concentration of 1%. With the increase in alkaline concentration (for 1%–2%), the degree of decomposition of hemicellulose and amorphous cellulose increased gradually. When the concentration of alkaline reagent was higher than 3%, more than 40% of hemicellulose was degraded. A complete surface structure of a spatial network was achieved when corn stalk was treated by 2% alkaline, which mainly contributed to the bonding performance of compound briquette. Under this condition, the ratio of cellulose to hemicellulose to lignin was approximately 7.0:2.5:0.5, and it also exhibited a good pyrolysis performance for energy conversion.
Co-reporter:Yang Zhang, Weihua Xiao, Guanya Ji, Chongfeng Gao, ... Lujia Han
Food and Bioproducts Processing 2017 Volume 105(Volume 105) pp:
Publication Date(Web):1 September 2017
DOI:10.1016/j.fbp.2017.05.002
•Grinding effects on microstructures, phytochemicals and antioxidation were compared.•Microstructural changes by cell-scale grinding affected the diffusion of components.•Cell-scale grinding enhanced the extractable water-soluble macromolecules.•Cell-scale grinding improved the product quality by enhancing antioxidant capacity.•Organ-scale grinding could meet the need to extract sufficient micromolecules.Mechanical grinding of tea is a crucial step in tea processing which can influence the quality and utilization of tea products. To investigate the effects of different grinding scale on black tea, particles at organ (∼mm), tissue (500–100 μm), and cell (50–10 μm) scales, were produced to compare their microstructural, compositional, molecular, antioxidant and dynamic extraction properties. The results proved organ and tissue-scale particles had similar properties, whereas cell-scale particles were significantly altered. In detail, for particles, the decrease in particle size resulted in an increase in cell wall breakage ratio, specific surface area, exposure of inner pores and depolymerized cell wall components on particle surfaces. According to the results of dynamic extraction, extraction equilibrium of the components could be obtained within 45 min. For water extracts at extraction equilibrium, microstructural changes at cell scale affected the diffusion process of phytochemicals, leading to more extractable macromolecules (protein and polysaccharide) and homogeneous particles, which enhanced antioxidant activity. However, the infusion yields of cytoplasmic micromolecules (tea polyphenols, caffeine, and free sugars) were not influenced by different grinding process. In conclusion, organ-scale grinding can meet the need for micromolecule-aimed products, while cell-scale grinding is essential for structure, macromolecule and antioxidation-enhanced products.
Co-reporter:Jinyi Ge, Guangqun Huang, Jing Huang, Jianfei Zeng, and Lujia Han
Environmental Science & Technology 2016 Volume 50(Issue 8) pp:4374
Publication Date(Web):April 5, 2016
DOI:10.1021/acs.est.5b04141
Inefficient aerobic composting techniques significantly contribute to the atmospheric methane (CH4) levels. Macro-scale models assuming completely aerobic conditions cannot be used to analyze CH4 generation in strictly anaerobic environments. This study presents a particle-scale model for aerobic pig manure/wheat straw composting that incorporates CH4 generation and oxidation kinetics. Parameter estimation revealed that pig manure is characterized by high CH4 yield coefficient (0.6414 mol CH4 mol–1 Cman) and maximum CH4 oxidation rate (0.0205 mol CH4 kg–1 VSaero h–1). The model accurately predicted CH4 emissions (R2 = 0.94, RMSE = 2888 ppmv, peak time deviation = 0 h), particularly in the self-heating and cooling phases. During mesophilic and thermophilic stages, a rapid increase of CH4 generation (0.0130 mol CH4 kg–1 VS h–1) and methanotroph inactivation were simulated, implying that additional measures should be performed during these phases to mitigate CH4 emissions. Furthermore, CH4 oxidation efficiency was related to oxygen permeation through the composting particles. Reducing the ambient temperature and extending the aeration duration can decrease CH4 emission, but the threshold temperature is required to trigger the self-heating phase. These findings provide insights into CH4 emission during composting and may inform responsible strategies to counteract climate change.
Co-reporter:Longjian Chen, Junbao Li, Minsheng Lu, Xiaomiao Guo, Haiyan Zhang, Lujia Han
Carbohydrate Polymers 2016 Volume 141() pp:1-9
Publication Date(Web):5 May 2016
DOI:10.1016/j.carbpol.2015.12.079
•Both acid pretreatment (AP) and enzymolysis (EL) of corn stover were characterized.•AP decreased hemicellulose from 19.7% in raw substrate to 9.28%.•AP increased pore volume from 0.0067 cm3/g in raw substrate to 0.019 cm3/g.•Enzyme adsorption in AP substrate was three-fold higher than that in raw substrate.•EL proceeded in the parallel hydrolysis mode of crystalline/amorphous cellulose.Corn stover was pretreated with acid under moderate conditions (1.5%, w/w, 121 °C, 60 min), and kinetic enzymolysis experiments were performed on the pretreated substrate using a mixture of Celluclast 1.5 L (20 FPU/g dry substrate) and Novozyme 188 (40 CBU/g dry substrate). Integrated chemical and multi-scale structural methods were then used to characterize both processes. Chemical analysis showed that acid pretreatment removed considerable hemicellulose (from 19.7% in native substrate to 9.28% in acid-pretreated substrate) and achieved a reasonably high conversion efficiency (58.63% of glucose yield) in the subsequent enzymatic hydrolysis. Multi-scale structural analysis indicated that acid pretreatment caused structural changes via cleaving acetyl linkages, solubilizing hemicellulose, relocating cell wall surfaces and enlarging substrate porosity (pore volume increased from 0.0067 cm3/g in native substrate to 0.019 cm3/g in acid-pretreated substrate), thereby improving the polysaccharide digestibility.
Co-reporter:Weihua Xiao, Xueli Chen, Yuxuan Zhang, Tianjiao Qu, and Lujia Han
Energy & Fuels 2016 Volume 30(Issue 10) pp:8246
Publication Date(Web):August 17, 2016
DOI:10.1021/acs.energyfuels.6b01186
The microwave-assisted methanolysis products from lignocellulose were analyzed with gas chromatography/mass spectrometry. Methyl levulinate (ML) and levoglucosenone derived from cellulose and furfural derived from hemicellulose were identified as the dominant compounds in corn stover methanolysis products. Only ML was revealed to accumulate rapidly over time in the methanolysis of cellulose and corn stover. The ML yields ranged from 34.9 to 84.5 mol % depending upon the starting materials varied among glucose, fructose, sucrose, cellulose, and corn stover. As a consequence of microwave dielectric heating, the ML yields from saccharides were increased significantly by 1.2–13.2 times compared to conventional heating. The results indicate that microwave-assisted methanolysis is a promising technology for the utilization of lignocellulosic materials.
Co-reporter:Xingfan Zhou, Zengling Yang, Simon A. Haughey, Pamela Galvin-King, Lujia Han, Christopher T. Elliott
Food Chemistry 2015 Volume 189() pp:13-18
Publication Date(Web):15 December 2015
DOI:10.1016/j.foodchem.2014.09.104
•Classification the geographical origin of DDGS by NIRS was feasible.•DDGS samples from China, Europe and USA have distinctive chemical properties.•Classification model were simplified by CARS selected variables.•Selected variables associated compositions well interpret the classification results.In this study, 137 corn distillers dried grains with solubles (DDGS) samples from a range of different geographical origins (Jilin Province of China, Heilongjiang Province of China, USA and Europe) were collected and analysed. Different near infrared spectrometers combined with different chemometric packages were used in two independent laboratories to investigate the feasibility of classifying geographical origin of DDGS. Base on the same dataset, one laboratory developed a partial least square discriminant analysis model and another laboratory developed an orthogonal partial least square discriminant analysis model. Results showed that both models could perfectly classify DDGS samples from different geographical origins. These promising results encourage the development of larger scale efforts to produce datasets which can be used to differentiate the geographical origin of DDGS and such efforts are required to provide higher level food security measures on a global scale.
Co-reporter:X. Liu, C. J. Huang, and L. J. Han
Energy & Fuels 2015 Volume 29(Issue 10) pp:6450-6455
Publication Date(Web):September 1, 2015
DOI:10.1021/acs.energyfuels.5b01259
The objective of this study was to investigate the effects of different scanning temperatures and accessories on the near-infrared reflectance spectroscopy (NIRS) prediction of straw and to assess the potential of calibration transfer of the NIRS model for calorific value prediction. Three scanning temperatures (15, 25, and 35 °C) and two accessories were used, and the typical temperature of 25 °C was denoted as the master condition. Three correction and transfer methods were tested and evaluated: slope/bias, difference spectra, and local centering. Our results showed that the scanning temperature exhibited a more significant effect on the NIRS prediction of the calorific value for the straw samples than the accessory, and the prediction errors for 15 °C were higher than those for 35 °C. Both the slope/bias and local centering methods could improve the predictions, but not all of the results were acceptable. The best result was provided by the local centering method for transferring the calibrations between different scanning temperatures and accessories, and it was determined to be efficient and useful. These results are relevant for the broader application of using near-infrared spectroscopy for energy quality control of straw, not only for the raw material but also for the conversion processing products.
Co-reporter:Longjian Chen;Ouarda Saib;Guoping Lian
Pharmaceutical Research 2015 Volume 32( Issue 5) pp:1779-1793
Publication Date(Web):2015 May
DOI:10.1007/s11095-014-1575-0
To develop in-silico model for predicting percutaneous absorption and disposition kinetics of chemicals in skin layers so as to facilitate the design of transdermal drug delivery systems and skin care products, and risk assessment of occupational or consumer exposure.A general-purpose computer model for simulating skin permeation, absorption and disposition kinetics in the stratum corneum, viable dermis and dermis has been developed. Equations have been proposed for determining the partition and diffusion properties of chemicals by considering molecular partition, binding and mobility in skin layers. In vitro skin penetration data of 12 chemicals was used to validate the model.The observed and simulated permeation and disposition in skin layers were compared for 12 tested chemicals. For most tested chemicals, the experimental and model results are in good agreement with the coefficient of determination >0.80 and relative root mean squared error <1.20. The disposition kinetic parameters of the maximum concentration and the area under the curve in the viable epidermis and dermis initially increased with hydrophobicity, but reached maxima and then decreased with further increase of hydrophobicity.By considering skin physiological structure and composition, the partition and diffusion properties of chemicals in skin layers are determined. This allows in-silico simulation of percutaneous permeation, absorption and disposition kinetics of wide chemical space. The model produced results in good agreement with experimental data of 12 chemicals, suggesting a much improved framework to support transdermal delivery of drug and cosmetic actives as well as integrated risk assessment.
Co-reporter:Jinyi Ge, Guangqun Huang, Zengling Yang, Jing Huang, and Lujia Han
Environmental Science & Technology 2014 Volume 48(Issue 9) pp:5043-5050
Publication Date(Web):April 3, 2014
DOI:10.1021/es500070z
A new method for characterizing the aerobic layer thickness in pig manure based on Fourier transform infrared microspectroscopy (FTIRM) is presented to improve the anaerobic/aerobic co-process mechanism, to ensure adequate oxygen supply and, thus, minimize methane emissions during aerobic composting. Freeze-dried manure particles were microtomed into 10 μm thick sections; the spectral range, spectral resolution, and pixel dimensions in the transmission spectra were 4000–650 cm–1, 16 cm–1, and 6.25 × 6.25 μm, respectively. A mean spectrum of 16 scans was used for the second-derivative analysis with nine smoothing points. This is the first attempt at determining the oxidation profile of composting particles according to the radial variations in second-derivative spectra at 2856 and 1568 cm–1, which are attributed to the reactants and products of the oxidation, respectively. In addition, an intermediate area is detected between the aerobic layer and anaerobic core. The experimental values of the aerobic layer thickness are consistent with the estimates, and an exponential increase is observed, which is influenced by multiple dynamic factors. However, the contribution of each factor to dynamic variations in the aerobic layer thickness should be investigated using available methods.
Co-reporter:Yanyan Zhao;Jan K. Marzinek;Peter J. Bond;Longjian Chen;Qiong Li;Athanasios Mantalaris;Efstratios N. Pistikopoulos;Massimo G. Noro;Guoping Lian
Journal of Pharmaceutical Sciences 2014 Volume 103( Issue 4) pp:1224-1232
Publication Date(Web):
DOI:10.1002/jps.23895
Iron binding to protein is common in biological processes of dioxygen transport, electron transfer as well as in stabilizing drug–protein complexes. α-Helix is the most prevalent secondary structure of proteins. In this study, Fe2+ binding to α-helix has been studied by isothermal titration calorimetry (ITC) and explicitly solvated molecular dynamics (MD) simulation. Ferrous gluconate and α-helix-rich keratin are used for the ITC study and the results revealed followed one set of identical sites binding model. The MD simulations further revealed that only the acidic side-chain functional groups and η2(O,O) coordination modes are involved in the binding of Fe2+ to α-helix. The ITC results also showed that the binding of ferrous gluconate to keratin was entropy driven and the higher the temperature, the stronger the binding free energy. The favorable entropy of Fe2+ binding to keratin was attributed to the displacement of water molecules on the α-helix surface, and was confirmed via MD simulations. The most stable coordination states of Fe2+ and α-helix were identified via simulation: Fe2+ stacks between two glutamic acid side chain carboxylate groups, displacing water molecules. The binding free energies calculated using MD simulation and the theoretical values were in excellent agreement with the ITC results. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 103:1224–1232, 2014
Co-reporter:Wenjuan Niu, Guangqun Huang, Xian Liu, Longjian Chen, and Lujia Han
Energy & Fuels 2014 Volume 28(Issue 12) pp:7474-7482
Publication Date(Web):November 13, 2014
DOI:10.1021/ef501446r
Rapid assessment of wheat straw at different maturity stages will help to reveal its growth mature and enable better process control that will optimize the sustainable value-added usage. This study explored the potential of near-infrared reflectance (NIR) spectroscopy to quantitatively and qualitatively analyze the multiple chemical composition and calorific value of wheat straw at different maturity stages. Partial least-squares (PLS) and genetic algorithm and partial least-squares (GA-PLS) models were used for NIR spectroscopy analysis. Results showed that PLS models and GA-PLS models could be both used for the estimation of chemical composition and calorific value of wheat straw at three maturity stages, and the GA-PLS method reduced the spectral variables for modeling and provided sensitive spectral variables correlated well with chemical composition and calorific value. NIR spectroscopy could successfully detect the contents of water-soluble carbohydrates (WSC), crude protein (CP), acid detergent fiber (ADF), neutral detergent fiber (NDF), ash, and nitrogen (N). It was also able to quantify dry matter (DM), cellulose (Cel), moisture (Moist), volatile matter (VM), higher heating value (HHV), and lower heating value (LHV). The NIR models for hemicellulose (Hem), lignin (Lig), carbon (C), sulfur (S), and hydrogen (H) had moderate accuracy, and could be used for qualitative analysis, whereas for fixed carbon (FC), it was suitable for screening purposes.
Co-reporter:Yang Yang;Guanya Ji;Weihua Xiao
Cellulose 2014 Volume 21( Issue 5) pp:3257-3268
Publication Date(Web):2014 October
DOI:10.1007/s10570-014-0381-5
To investigate changes on the physicochemical characteristics of wheat straw by mechanical ultrafine grinding, wheat straw powders of four different particle sizes and distributions were produced using a sieve-based Retsch ZM100 grind mill and CJM-SY-B ultrafine vibration grind mill. Changes on the microstructure and physicochemical characteristics of the different powders were assessed by scanning electron microscopy, X-ray diffractometry, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis and relevant standard laboratory analysis methods. Ultrafine grinding reduced the crystallite size and crystallinity of the wheat straw. New surfaces were exposed on the ultrafine powder with high levels of cellulose/hemicelluloses components but there was no apparent change in chemical structure. Wheat straw powders were smaller in size but had a higher bulk density (from 0.19 to 0.54 g/mL) and angle of repose (from 46.02° to 55.61°) and slide (from 37.26° to 41.00°). The hydration properties (water-holding capacity and swelling capacity) decreased with reduction in particle size of the wheat straw. Both the sieve-based and ultrafine powder exhibited a good ability to remove Pb2+ and Cd2+ and there was marginal improvement when using the ultrafine powder. The thermal stability of the ultrafine powder measured by thermogravimetric analysis decreased significantly because of the low cellulose crystallinity.
Co-reporter:Wenjuan Niu, Xian Liu, Guangqun Huang, Longjian Chen, and Lujia Han
Energy & Fuels 2013 Volume 27(Issue 10) pp:5940-5947
Publication Date(Web):September 10, 2013
DOI:10.1021/ef401284n
Physicochemical properties of wheat straw play crucial roles in bioenergy and chemical conversion processes. Four wheat straw cultivars at different maturity levels were collected in Beijing, China, and the growth days (GDs) ranged from 236 to 263 days. The physicochemical compositions and energy properties were analyzed. Cellulose (Cel), hemicelluloses (Hem), monosaccharidic composition of hemicelluloses (xylan, arabinan, hemicellulosic glucan, galactan, and mannan), and dry matter (DM) increased from 236 to 263 days, which can be explained by the increasing lignification of the cell walls in wheat straw with maturity. Water-soluble carbohydrates (WSC), crude protein (CP), nitrogen (N), phosphorus (P), and copper (Cu) decreased initially and then leveled off, with leaves decreasing. Lignin (Lig), ash, sulfur (S), potassium (K), and sodium (Na) increased first and then decreased slightly to 263 days. Carbon (C), hydrogen (H), oxygen (O), volatile matter (VM), fixed carbon (FC), and higher heating value (HHV) had litter variation with advancing maturity. A number of significant correlations were found among different physicochemical compositions. Regression equations for Cel and DM based on GDs showed excellent performance for prediction, while models for WSC and CP showed good prediction.
Co-reporter:Weihua Xiao, Wenjuan Niu, Fei Yi, Xian Liu, and Lujia Han
Energy & Fuels 2013 Volume 27(Issue 6) pp:3204-3208
Publication Date(Web):April 30, 2013
DOI:10.1021/ef4003457
Microwave-assisted polyhydric liquefaction of crop residues was a useful method for the conversion of lignocelluloses into biopolyols. Five types of crop residues were selected to investigate the effect of feedstock varieties on the microwave-assisted liquefaction performance and products. The microwave-assisted liquefaction characteristic of different feedstocks in ethylene glycol (EG) was evaluated by residue component analysis and kinetics modeling. Cellulose was proven to be the main residual content, and hemicelluloses and lignin were liquefied rapidly. According to the first-order model, degradation of cellulose was indicated to be the rate-determining step in the microwave solvolysis liquefaction of crop residues. Among the five types of crop residues, rice straw was the material most difficult to be liquefied. Acid-insoluble ash (AIA) was found to be significantly negatively correlated with the liquefaction rate of crop residues and cellulose. The hydroxyl number and acid number of microwave-assisted liquefaction products (MLPs) from different feedstocks varied with different crop residues.
Co-reporter:Yanyan Zhao, Longjian Chen, Gleb Yakubov, Termeh Aminiafshar, Lujia Han, and Guoping Lian
The Journal of Physical Chemistry B 2012 Volume 116(Issue 43) pp:13010-13016
Publication Date(Web):April 16, 2012
DOI:10.1021/jp212059x
Binding of epigallocatechin gallate (EGCG) to highly purified short side-chain porcine gastric mucin similar to human MUC6 type has been studied by ultraviolet–visible absorption spectroscopy (UV–vis), ultrafiltration isothermal titration microcalorimetry (ITC) and transmission electron microscopy (TEM). The thermodynamic equilibrium of EGCG binding to mucin has been quantitatively determined using ultrafiltration and high-performance liquid chromatography (HPLC)–UV/vis. The relationship suggests multilayer binding rather than simple Langmuir monolayer binding of EGCG. By combining the ultrafiltration and ITC data, the thermodynamic parameters of EGCG binding to mucin have been obtained. The binding constant for the first layer is about an order of magnitude higher than that of the consecutive multilayers. Negative entropy indicates multilayer of EGCG formed. Hydrogen bonding may be responsible for the multilayer formation. Increasing temperature resulted in a decrease in the binding affinity, further suggesting that hydrogen bonds dominated the interaction energy. A TEM micrograph of the EGCG–mucin complex revealed a monodispersion of blobs similar to pure mucin solution but with relatively bigger size (about twice). It is proposed that the EGCG–mucin binding process occurs by single and/or cluster of EGCG molecules driven to the surface of the two hydrophobic globules of mucin by hydrophobic interaction followed by hydrogen bond interaction between EGCG and mucin. Further adsorption of EGCG molecules onto bound EGCG molecules to form multilayers can also occur. This fits well with the observations that EGCG–mucin interaction followed a multilayer adsorption isotherm, the energy released is dominated by hydrogen bonds, and no large aggregates were formed.
Co-reporter:Weihua Xiao, Lujia Han, Bo Shi
Journal of Chromatography B 2009 Volume 877(8–9) pp:697-702
Publication Date(Web):15 March 2009
DOI:10.1016/j.jchromb.2009.01.034
High-speed counter-current chromatography methods, combined with resin chromatography were applied to the separation and purification of flavonoid glycosides from the Chinese medicinal herb, Radix Astragali. Five flavonoid glycosides, namely calycosin-7-O-β-d-glucoside, ononin, (6aR, 11aR)-9,10-dimethoxypterocarpan-3-O-β-d-glucoside, (3R)-2′-hydroxy-3′,4′-dimethoxyisoflavan-7-O-β-d-glucoside and calycosin-7-O-β-d-glucoside-6′′-O-acetate, were obtained. Among them, calycosin-7-O-β-d-glucoside-6′′-O-acetate was preparatively separated from Radix Astragali for the first time. Their structures were identified by ESI–MS, 1H NMR, 13C NMR, and 2D NMR.
Co-reporter:Weihua Xiao, Lujia Han, Bo Shi
Separation and Purification Technology 2008 Volume 62(Issue 3) pp:614-618
Publication Date(Web):22 September 2008
DOI:10.1016/j.seppur.2008.03.025
Microwave-assisted extraction (MAE) technique was developed for the fast extraction of flavonoids from Radix Astragali. Several influential parameters of the MAE procedure (microwave power, extraction cycles, ethanol concentration, extraction temperature, irradiation time, and solvent to material ratio) were studied for the optimization of the extraction protocol. The maximum yield of flavonoids with MAE was obtained by dual extraction with 90% ethanol 25 ml/g material at 110 °C for 25 min. No degradation of the flavonoids was observed using the developed extraction protocol. The optimal yield with MAE 1.190 ± 0.042 mg/g were close to that of Soxhlet extracted with methanol for 4 h (1.292 ± 0.033 mg/g) and higher than that of ultrasound assisted extraction with methanol for 2× 30 min and heat reflux extraction with 90% ethanol for 2× 2 h.
Co-reporter:Guoping Lian;Longjian Chen
Journal of Pharmaceutical Sciences 2008 Volume 97( Issue 1) pp:584-598
Publication Date(Web):
DOI:10.1002/jps.21074
Abstract
A number of mathematical models have been proposed for predicting skin permeability, mostly empirical and very few are deterministic. Early empirical models use simple lipophilicity parameters. The recent trend is to use more complicated molecular structure descriptors. There has been much debate on which models best predict skin permeability. This article evaluates various mathematical models using a comprehensive experimental dataset of skin permeability for 124 chemical compounds compiled from various sources. Of the seven models compared, the deterministic model of Mitragotri gives the best prediction. The simple quantitative structure permeability relationships (QSPR) model of Potts and Guy gives the second best prediction. The two models have many features in common. Both assume the lipid matrix as the pathway of transdermal permeation. Both use octanol–water partition coefficient and molecular size. Even the mathematical formulae are similar. All other empirical QSPR models that use more complicated molecular structure descriptors fail to provide satisfactory prediction. The molecular structure descriptors in the more complicated QSPR models are empirically related to skin permeation. The mechanism on how these descriptors affect transdermal permeation is not clear. Mathematically it is an ill-defined approach to use many colinearly related parameters rather than fewer independent parameters in multi-linear regression. © 2007 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 97:584–598, 2008
Co-reporter:Xiu-Xia Li;Lu-Jia Han
European Food Research and Technology 2008 Volume 227( Issue 5) pp:
Publication Date(Web):2008 September
DOI:10.1007/s00217-008-0878-y
Lutein, zeaxanthin, and β-cryptoxanthin are xanthophyll pigments that own conjugated double bonds; some factors can convert (all-E)-xanthophylls to their (Z)-isomers such as high temperature, illumination, and oxidants. In the present work, the Fe(II)-induced isomerization of (all-E)-lutein, (all-E)-zeaxanthin, and (all-E)-β-cryptoxanthin in acetone were analyzed by HPLC coupled with DAD and APcI-MS. The three (all-E)-xanthophylls were baseline separated and their (Z)-isomers were identified by the chromatographic retention, UV/vis spectra and positive mass spectrometry with reference values reported in the literature. The results showed that Fe(II) exhibited a rapidly isomerization induction of (all-E)-xanthophylls to their (Z)-isomers exceeding a 8/1 mass ratio of Fe(II)/pigments. The (13-Z)-lutein and (13′-Z)-lutein were identified as the major (Z)-isomers of (all-E)-lutein treated with FeSO4·7H2O, and (13-Z)-zeaxanthin was identified as the major isomerization product of (all-E)-zeaxanthin. Furthermore, a type of (Z)-β-cryptoxanthin was also detected. Increasing either mass ratio of Fe(II)/pigments or the incubation time of FeSO4·7H2O and (all-E)-xanthophylls may affect on the stabilities of (Z)-isomers derived from (all-E)-xanthophylls.
Co-reporter:Longjian Chen, Li Xing, Lujia Han, Zengling Yang
Biosystems Engineering (September 2009) Volume 104(Issue 1) pp:
Publication Date(Web):1 September 2009
DOI:10.1016/j.biosystemseng.2009.06.008
With the increasing concern over the potential pollution from farm wastes, there is a need for rapid and robust methods that can evaluate livestock manure nutrient content. Physicochemical models which related cattle manure nutrient content (ammonium nitrogen, AN; total potassium, TK; total nitrogen, TN; total phosphorus, TP) to its physicochemical properties (specific gravity, dry matter, electrical conductivity, pH) have been reported by previous researchers. This study reviewed previous physicochemical models and compiled the observed data drawn from a wide selection of sources to validate various physicochemical models. Several statistical parameters, including the coefficient of determination R2, the modelling efficiency statistic, the mean squared error of prediction, the mean bias, and the linear bias, were calculated to evaluate model performance on the data sets. The results showed that the relationship (AN = 0.136EC − 0.523) developed by Scotford et al. (1998b), provided satisfactory predictions for AN with R2 = 0.75. The equation (TP = 0.01DM + 0.057) developed by Higgins et al. (2004) gave reasonable prediction for TP with R2 = 0.77. The corrected TK model (TK = 0.184EC + 0.042) greatly reduced systemic errors and hence improved TK prediction with R2 = 0.87. Compared with prediction models for other nutrient contents, TN physicochemical models provided far from satisfactory predictions but equations used by Marino et al. (2008) was the best (R2 = 0.62).
Co-reporter:X. Liu, L.J. Han, Z.L. Yang
Journal of Dairy Science (November 2011) Volume 94(Issue 11) pp:5599-5610
Publication Date(Web):1 November 2011
DOI:10.3168/jds.2011-4375
This study was undertaken to distinguish different collected spectra from near infrared reflectance spectroscopy (NIRS) for silages using different configurations and types of NIRS, and how well the different techniques for transferring NIRS calibrations perform for silage crude protein detection. In the study, 2 Fourier transform instruments and 1 scanning grating instrument were involved. Five correction and transfer methods were tested and evaluated: slope/bias, local centering, orthogonal signal correction, direct standardization, and piecewise direct standardization. We concluded that the spectra obtained with 3 instruments were different and not solely due to the differences in offset. All of the methods for calibration transferring between 2 Fourier transform instruments and 1 Fourier transform instrument versus 1 scanning grating instrument could improve the predictions, but not all of the results could be accepted. The slope/bias, orthogonal signal correction, and local centering techniques were successful for calibration transferring of 2 Fourier transform instruments, considering their good performance. The best result was given for orthogonal signal correction ahead of the other 4 techniques for transferring calibrations between instruments of Fourier transform and scanning grating, and it was evaluated as moderately useful.
Co-reporter:Longjian Chen, Li Xing, Lujia Han
Biosystems Engineering (November 2008) Volume 101(Issue 3) pp:
Publication Date(Web):1 November 2008
DOI:10.1016/j.biosystemseng.2008.09.005
With increasing concern over the potential pollution from farm wastes, there is a need for rapid and robust methods that can analyse animal manure. In order to evaluate rapid testing methods based on the relationship between layer manure composition (ammonium nitrogen, total potassium, total nitrogen, total phosphorus, iron, copper, zinc, magnesium and sodium) and physicochemical properties (specific gravity, electrical conductivity, pH), diverse layer manure samples (n = 105) were used. Relationships were investigated using linear regression and artificial neural networks (ANNs). The performance of a neural network-based model was compared with a linear regression-based model using the same observed data. It was found that ANN model consistently gives better predictions. Based on the results of this study, ANNs appear to be a promising technique for predicting layer manure composition.
Co-reporter:Longjian Chen, Li Xing, Lujia Han, Zengling Yang
Biosystems Engineering (July 2009) Volume 103(Issue 3) pp:
Publication Date(Web):1 July 2009
DOI:10.1016/j.biosystemseng.2009.04.007
Prediction models for rapidly determining the nutrient content of pig manures will become important as environmental regulations increase the requirements for this information. Physicochemical models which related pig manure nutrient content (ammonium nitrogen, AN; total potassium, TK; total nitrogen, TN; total phosphorus, TP) to its physicochemical properties (specific gravity, dry matter, electrical conductivity, pH) have been reported by previous researchers. This study reviewed previous physicochemical models and compiled the observed data drawn from a wide selection of sources to validate various physicochemical models. Several statistical parameters, including the coefficient of determination (R2), the modelling efficiency statistic, the mean squared error of prediction, the mean bias, and the linear bias, were calculated to evaluate model performance on the datasets. The results showed that the relationship developed by Scotford et al. [Scotford I M; Cumby T R; White R P; Carton O T; Lorenz F; Hatterman U, et al. (1998b). Estimation of the nutrient value of agricultural slurries by measurement of physical and chemical properties. Journal of Agricultural Engineering Research, 71(3), 291–305], can provide satisfactory predictions for AN with R2 = 0.89. The equations developed by Scotford et al. [Scotford I M; Cumby T R; White R P; Carton O T; Lorenz F; Hatterman U, et al. (1998b). Estimation of the nutrient value of agricultural slurries by measurement of physical and chemical properties. Journal of Agricultural Engineering Research, 71(3), 291–305] and Zhu et al. [Zhu J; Zhang Z; Ndegwa P M (2003). Using a soil hydrometer to measure the nitrogen and phosphorus contents in pig slurries. Biosystems Engineering, 85(1), 121–128], gave reasonable prediction for TK and TP with R2 = 0.88 and 0.78, respectively. Compared with prediction models for other nutrient contents, TN physicochemical models provided far from satisfactory predictions but equations used by Martinez-Suller et al. [Martinez-Suller L; Azzellino A; Provolo G (2008). Analysis of livestock slurries from farms across northern Italy: relationship between indicators and nutrient content. Biosystems Engineering, 99(4), 540–552], were the best (R2 = 0.73). These findings demonstrated that physicochemical model may be an appropriate tool to predict AN, TK, and TP content of pig manure, however, further work is needed to develop and validate TN physicochemical models.
Co-reporter:Longjian Chen, Lujia Han, Guoping Lian
Advanced Drug Delivery Reviews (February 2013) Volume 65(Issue 2) pp:295-305
Publication Date(Web):1 February 2013
DOI:10.1016/j.addr.2012.05.001
Understanding the permeation of hydrophilic molecules is of relevance to many applications including transdermal drug delivery, skin care as well as risk assessment of occupational, environmental, or consumer exposure. This paper reviews recent advances in modeling skin permeability of hydrophilic solutes, including quantitative structure–permeability relationships (QSPR) and mechanistic models. A dataset of measured human skin permeability of hydrophilic and low hydrophobic solutes has been compiled. Generally statistically derived QSPR models under-estimate skin permeability of hydrophilic solutes. On the other hand, including additional aqueous pathway is necessary for mechanistic models to improve the prediction of skin permeability of hydrophilic solutes, especially for highly hydrophilic solutes. A consensus yet has to be reached as to how the aqueous pathway should be modeled. Nevertheless it is shown that the contribution of aqueous pathway can constitute to more than 95% of the overall skin permeability. Finally, future prospects and needs in improving the prediction of skin permeability of hydrophilic solutes are discussed.Download high-res image (99KB)Download full-size image
Co-reporter:Yanyan Zhao, Jan K. Marzinek, Peter J. Bond, Longjian Chen, ... Guoping Lian
Journal of Pharmaceutical Sciences (April 2014) Volume 103(Issue 4) pp:1224-1232
Publication Date(Web):1 April 2014
DOI:10.1002/jps.23895
Iron binding to protein is common in biological processes of dioxygen transport, electron transfer as well as in stabilizing drug–protein complexes. α-Helix is the most prevalent secondary structure of proteins. In this study, Fe2+ binding to α-helix has been studied by isothermal titration calorimetry (ITC) and explicitly solvated molecular dynamics (MD) simulation. Ferrous gluconate and α-helix-rich keratin are used for the ITC study and the results revealed followed one set of identical sites binding model. The MD simulations further revealed that only the acidic side-chain functional groups and η2(O,O) coordination modes are involved in the binding of Fe2+ to α-helix. The ITC results also showed that the binding of ferrous gluconate to keratin was entropy driven and the higher the temperature, the stronger the binding free energy. The favorable entropy of Fe2+ binding to keratin was attributed to the displacement of water molecules on the α-helix surface, and was confirmed via MD simulations. The most stable coordination states of Fe2+ and α-helix were identified via simulation: Fe2+ stacks between two glutamic acid side chain carboxylate groups, displacing water molecules. The binding free energies calculated using MD simulation and the theoretical values were in excellent agreement with the ITC results. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 103:1224–1232, 2014
Co-reporter:Zengling Yang, Lujia Han, Xian Liu, Qiongfei Li
Animal Feed Science and Technology (15 December 2008) Volume 147(Issue 4) pp:357-367
Publication Date(Web):15 December 2008
DOI:10.1016/j.anifeedsci.2008.02.005
