Structural characterization of three acidic polysaccharides from Opuntia dillenii Haw.fruits and their protective effect against hydrogen peroxide-induced oxidative stress in Huh-7 cells

Three novel acidic polysaccharide fractions(OFPP-1,OFPP-2,OFPP-3)with different m olecular weights(803.7,555.1 and 414.5 k Da)were isolated from the peeled Opuntia dillenii Haw.fruits by alkali-extraction,graded alcohol precipitation and column chromatography.Structural analysis indicated that OFPPs were pectic polysaccharides consisting of rhamnose,arabinose and galactose residues.The backbone of OFPP-1 consisted of a repeating unit→6-α-D-Galp A-(1→2)-α-L-Rhap-(1→with T-α-D-Galp A-(1→6)-α-D-Galp A-(1→4)-α-D-Glcp-(1→,T-β-D-Xylp-(1→6)-α-D-Galp A-(1→4)-α-D-Glcp-(1→or T-α-D-Galp A-(1→3)-α-L-Araf-(1→as the side chains.The backbone of OFPP-2 consisted of a disaccharide repeating unit→2)-α-L-Rhap-(1→4)-β-D-Galp A-(1→with T-β-L-Araf-(1→as the branches substituted at the O-4 position of→2,4)-α-LRhap-(1→.Whereas the backbone of OFPP-3 was→2,4)-α-L-Rhap-(1→2)-α-L-Rhap-(1→3)-β-L-Araf-(1→or→2,4)-α-L-Rhap-(1→2)-α-L-Rhap-(1→4)-β-D-Galp A-(1→,which was branched at the O-4 position of→2,4)-α-L-Rhap-(1→.Moreover,these three polysaccharide fractions could protect Huh-7 cells against H2O2-induced oxidative stress to different extents by decreasing the MDA content and increasing the SOD,CAT,GSH-Px activities and the GSH level in the Huh-7 cells.These results suggest that OFPPs have the potential to be used as natural antioxidants.

Structural characterization and anti-inflammatory activities of novel polysaccharides obtained from Pleurotus eryngii

Natural polysaccharides named PEP-0.1-1,PEP-0-1 and PEP-0-2 from edible mushroom species Pleurotus eryngii were obtained in the present study.Results showed that molecular weights of these polysaccharides were 3235,2041 and 23933 Da,respectively.Further,structural characterization revealed that PEP-0.1-1 had a→4-α-D-Glcp-1→backbone and contained→4)-α-D-Glcp and→4)-β-D-Glcp reducing end groups.PEP-0-1 backbone contained→4-α-D-Glcp-1→and→6-α-3-O-Me-D-Galp-1→,and the side chains containedα-D-Glcp,β-D-Manp-1→andα-D-Glcp-3→.However,PEP-0-2 backbone consisted of→4-α-DGlcp-1→and→6-α-3-O-Me-D-Galp-(1→6)-α-D-Galp-1→while the side chains containedα-D-Glcp andβ-D-Manp-1→.Biological activity analysis was then carried out and found that all these polysaccharides could significantly suppress the relative mRNA expression of toll-like receptor 4,nitric oxide(NO),tumor necrosis factor-α,interleukin(IL)-1βand IL-6 in lipopolysaccharide(LPS)-induced inflammation of RAW264.7 cells,as well as the over secretion of the above cell cytokines.Moreover,Western blotting analysis revealed that all these purified fractions displayed significant inhibition effects on the expression of c-Jun N-terminal kinases protein induced by LPS in mitogen activated protein kinase pathway,along with the relieving on the inhibition effect of LPS on IκB-αprotein expression.In summary,the information generated by the present study could provide a theoretical basis for the exploration of novel healthy food materials from edible mushroom with antiinflammation activities.

Structural characterizations andα-glucosidase inhibitory activities of four Lepidium meyenii polysaccharides with different molecular weights

Four polysaccharides(MCPa,MCPb,MCPc,MCPd)were obtained from Lepidium meyenii Walp.Their structures were characterized by chemical and instrumental methods including total sugar,uronic acid and protein content determi-nation,UV,IR and NMR spectroscopy,as well as monosaccharide composition determination and methylation analy-ses.Four polysaccharides were a group of glucans with different molecular weights ranging from 3.12 to 14.4 kDa,and shared a similar backbone chain consisting of(1→4)-glucose linkages with branches attached to C-3 and C-6.Furthermore,bioactivity assay showed that MCPs had concentration-dependent inhibitory activity onα-glucosidase.MCPb(Mw=10.1 kDa)and MCPc(Mw=5.62 kDa)with moderate molecular weights exhibited higher inhibitory activ-ity compared with MCPa and MCPd.

Structural characterization and immunostimulatory activity of a water-soluble polysaccharide from abalone(Haliotis discus hannai Ino)muscle

A water-soluble polysaccharide from abalone muscle(AMPP)was isolated.The contents of carbohydrate,protein,uronic acid,and sulfate in AMPP were 83.5%,0.5%,2.7%,and 2.6%,respectively.High-performance liquid chromatography analysis indicated that AMPP was homogeneous and had an average molecular weight of approximately 3.2 kDa.The main monosaccharides of AMPP were glucose(Glc)and mannose with a molar ratio of 99.7:0.3.The structural characteristics of AMPP were elucidated through methylation analysis,Fourier transform infrared spectroscopy,and nuclear magnetic resonance spectroscopy.The linkages of AMPP consisted of terminal,1,4-linked,1,6-linked,and 1,4,6-linked Glcp with a molar ratio of 3.1:7.2:1.0:2.5.In one repeat unit of the proposed AMPP structure,the backbone chain was composed of eight 1→4 glycosidic bonds and one 1→6 glycosidic bond,with three branch chains linked by 1→6 glycosidic bond.In addition,AMPP was found to possess potent immunostimulatory activity via rising phagocytosis of RAW264.7 cells and promoting secretion of TNF-α.

Physicochemical, structural characterization, and antioxidant activities of chondroitin sulfate from Oreochromis niloticus bones

In this study,chondroitin sulfate was extracted from Oreochromis niloticus bones(OCS)and isolated to three fractions(OCS-1,OCS-2,and OCS-3).The physicochemical properties and structure characterization including monosaccharide,disaccharide compositions,molecular weight(Mw)of OCS were determined by HPAEC,HPLC-SAX,HPGPC,FT-IR spectra,and 1D/2D NMR.Moreover,their thermal properties,crystalline structure,and microstructure were also analyzed.Results showed that their Mw were between 10 kDa and 50 kDa.CS-6 was the predominant disaccharide unit in four OCS,and the CS-4/CS-6 ratios were close to CS from shark cartilage.Besides,the results of antioxidant activity showed that different fractions of OCS had a distinct DPPH radical,hydroxyl radical,and ABTS+radical scavenging activity.OCS-1 has the highest scavenging activities in DPPH and hydroxyl radical compared with other fractions,which showed a higher medicinal value.Those findings may lay some theoretical basis for the potential application development of OCS.

Bio-soft matter derived from traditional Chinese medicine:Characterizations of hierarchical structure,assembly mechanism,and beyond

Structural and functional explorations on bio-soft matter such as micelles,vesicles,nanoparticles,aggregates or polymers derived from traditional Chinese medicine(TCM)has emerged as a new topic in the field of TCM.The discovery of such cross-scaled bio-soft matter may provide a unique perspective for unraveling the new effective material basis of TCM as well as developing innovative medicine and biomaterials.Despite the rapid rise of TCM-derived bio-soft matter,their hierarchical structure and assembly mechanism must be unambiguously probed for a further in-depth understanding of their pharmacological activity.In this review,the current emerged TCM-derived bio-soft matter assembled from either small molecules or macromolecules is introduced,and particularly the unambiguous elucidation of their hierarchical structure and assembly mechanism with combined electron microscopic and spectroscopic techniques is depicted.The pros and cons of each technique are also discussed.The future challenges and perspective of TCM-derived bio-soft matter are outlined,particularly the requirement for their precise in situ structural determination is highlighted.

Characterization of physicochemical and immunogenic properties of allergenic proteins altered by food processing:a review

Food allergens are mainly naturally-occurring proteins with immunoglobulin E(IgE)-binding epitopes.Understanding the structural and immunogenic characteristics of allergenic proteins is essential in assessing whether and how food processing techniques reduce allergenicity.We here discuss the impacts of food processing technologies on the modification of physicochemical,structural,and immunogenic properties of allergenic proteins.Detection techniques for characterizing changes in these properties of food allergens are summarized.Food processing helps to reduce allergenicity by aggregating or denaturing proteins,which masks,modifies,or destroys antigenic epitopes,whereas,it cannot eliminate allergenicity completely,and sometimes even improves allergenicity by exposing new epitopes.Moreover,most food processing techniques have been tested on purified food allergens rather than food products due to potential interference of other food components.We provide guidance for further development of processing operations that can decrease the allergenicity of allergenic food proteins without negatively impacting the nutritional profile.

Atomically self-healing of structural defects in monolayer WSe_(2)

Minimizing disorder and defects is crucial for realizing the full potential of two-dimensional transition metal dichalcogenides(TMDs) materials and improving device performance to desired properties. However, the methods in defect controlcurrently face challenges with overly large operational areas and a lack of precision in targeting specific defects. Therefore,we propose a new method for the precise and universal defect healing of TMD materials, integrating real-time imaging withscanning transmission electron microscopy (STEM). This method employs electron beam irradiation to stimulate the diffusionmigration of surface-adsorbed adatoms on TMD materials grown by low-temperature molecular beam epitaxy (MBE),and heal defects within the diffusion range. This approach covers defect repairs ranging from zero-dimensional vacancydefects to two-dimensional grain orientation alignment, demonstrating its universality in terms of the types of samples anddefects. These findings offer insights into the use of atomic-level focused electron beams at appropriate voltages in STEMfor defect healing, providing valuable experience for achieving atomic-level precise fabrication of TMD materials.

Effects of structural characterizations on fragility functions of bridges subject to seismic shaking and lateral spreading

This paper evaluates the seismic vulnerability of different classes of typical bridges in California when subjected to seismic shaking or liquefaction-induced lateral spreading. The detailed structural configurations in terms of superstructure type, connection, continuity at support and foundation type, etc. render different damage resistant capability. Six classes of bridges are established based on their anticipated failure mechanisms under earthquake shaking. The numerical models that are capable of simulating the complex soil-structure interaction effects, nonlinear behavior of columns and connections are developed for each bridge class. The dynamic responses are obtained using nonlinear time history analyses for a suite of 250 earthquake motions with increasing intensity. An equivalent static analysis procedure is also implemented to evaluate the vulnerability of the bridges when subjected to liquefaction-induced lateral spreading. Fragility functions for each bridge class are derived and compared for both seismic shaking （based on nonlinear dynamic analyses） and lateral spreading （based on equivalent static analyses） for different performance states. The study finds that the fragility functions due to either ground shaking or lateral spreading show significant correlation with the structural characterizations, but differences emerge for ground shaking and lateral spreading conditions. Structural properties that will mostly affect the bridges＇ damage resistant capacity are also identified.

Structural Characterization of Lignins Isolated from Caragana sinica Using FT-IR and NMR Spectroscopy

In order to efficiently explore and use woody biomass,six lignin fractions were isolated from dewaxed Caragana sinica via successive extraction with organic solvents and alkaline solutions.The lignin structures were characterized by Fourier transform infrared spectroscopy(FT-IR) and 1D and 2D Nuclear Magnetic Resonance(NMR).FT-IR spectra revealed that the "core" of the lignin structure did not significantly change during the treatment under the conditions given.The results of 1H and 13C NMR demonstrated that the lignin fraction L2,isolated with 70% ethanol containing 1% NaOH,was mainly composed of β-O-4 ether bonds together with G and S units and trace p-hydroxyphenyl unit.Based on the 2D HSQC NMR spectrum,the ethanol organosolv lignin fraction L1,extracted with 70% ethanol,presents a predominance of β-O-4′ aryl ether linkages(61% of total side chains),and a low abundance of condensed carbon-carbon linked structures(such as ββ′,β-1′,and β-5′) and a lower S/G ratio.Furthermore,a small percentage(ca.9%) of the linkage side chain was found to be acylated at the γ-carbon.

Extraction,Isolation and Structural Characterization of Polysaccharides from a Red Alga Gloiopeltis furcata

Three kinds of polysaccharides： GFW, GFH and GFA, were sequentially extracted from a red alga Gloiopeltisfurcata with 25℃ and 85℃ water, and 60℃ 4% NaOH water solution. Based on the defatted alga, the yields of the polysaccharide were 57.9%, 2.5% and 2.6%, respectively. Their monosaccharide compositions, average molecular weights and structural characters were determined by gas chromatography （GC）, high performance liquid chromatography （HPLC）, fourier transform infrared spectroscopy （FTIR） or ^13C-NMR spectroscopy. The results showed that GFW, GFH and GFA were all composed of D-galactose （Gal） and 3,6-anhydro-L-galactose （AnG）, and particularly GFA also contained xylose （Xyl）. The average molecular weights of GFW, GFH and GFA were 22.6 kD, 26.5 kD and 49.8 kD, respectively, with the respective sulfate content 31.2%, 25.1% and 22.7%. The data of FTIR and ^13C-NMR confirmed the sulfate ester location at C6 ofgalactose. It is concluded that all the three polysaecharides extracted from Gloiopeltisfurcata were sulfated galactans, two being sulfated-agarose, and one being xylose-containing sulfated galactan.

One-pot synthesis and structural characterization of urea-isobutyraldehyde-formaldehyde resin

Urea-isobutyraldehyde-formaldehyde (UIF) resin was synthesized from urea, isobutyraldehyde, and formaldehyde using sulfuric acid as a catalyst by one pot method. The effects of molar ratios of isobutyraldehyde to formaldehyde (n(I)/n(F)) and aldehyde to urea (n(A)/n(U)) on the yield, hydroxyl value (vs KOH) and softening point of the resin were investigated. The structure of the resin was characterized by FT-IR, 1H-NMR and 13C-NMR. The results show that when the molar ratio of urea to isobutyraldehyde to formaldehyde (n(U)/n(I)/n(F)) is 1.0/3.0/3.0, the yield UIF resin is 67.1%, and the softening point and hydroxyl value are 88 ℃ and 37 mg/g, respectively. The FT-IR, 1H-NMR and 13C-NMR results show that the lactam is formed by aminomethylation from urea, isobutyraldehyde, and formaldehyde.

Synthesis and structural characterization of macroporous bioactive glass

Porous sol-gel glass of CaO-SiO2-P2O5 system with macropores larger than 100 μm was prepared by adding stearic acid as pore former when the sintering was carried out at 700 ℃ for 3h.The sol-gel porous glass shows an amorphous structure. The diameter of the pore created by pore former varies from 100 to 300 μm, and macroporous glass has a narrow and small pore size distribution in mesoporous scale. The porosity and pore size of macroporous bioactive glass can be controlled.

A facile method for fabrication of nano-structured Ni-Al_2O_3 graded coatings: Structural characterization

Powder charges of micron-size Ni and Al2O3were utilized to deposit nano-structured Ni-Al2O3composite coatings on analuminum plate fixed at the top end of a milling vial using a planetary ball mill.Composite coatings were fabricated using powdermixtures with a wide range of Ni/Al2O3mass ratio varying from1:1to plain Ni.XRD,SEM and TEM techniques were employed tostudy the structural characteristics of the coatings.It was found that the composition of the starting mixture strongly affects the Al2O3content and the microstructure of the final coating.Mixtures containing higher contents of Al2O3yield higher volume fractions of theAl2O3particles in the coating.Though Ni-Al2O3composite coatings with about50%of Al2O3particles were successfully deposited,well-compacted and free of cracks and/or voids coatings included less than20%(volume fraction)of Al2O3particles which weredeposited from powder mixtures with Ni/Al2O3mass ratios of4:1or higher.Moreover,mechanical and metallurgical bondings arethe main mechanisms of the adhesion of the coating to the Al substrate.Finally,functionally graded composite coatings withnoticeable compaction and integrity were produced by deposition of two separate layers under identical coating conditions.

The structural characteristics of dietary fibers from Tremella fuciformis and their hypolipidemic effects in mice

In this study,Tremella fuciformis residues as raw material,dietary fibers from tremella were prepared by multiple enzymes.The structure of dietary fibers from tremella was studied by Fourier transform infrared(FTIR),X-ray diffraction analysis(XRD)and scanning electron microscopy(SEM).We analyzed their lipidlowering properties in vitro(water holding,oil holding swelling cholesterol and sodium cholate binding capacitises)and the hypolipidemic effects in mice.The results showed that tremella dietary fibers presented the infrared absorption spectrum characteristics of polysaccharides and the characteristic diffraction peaks of cellulose type I.SEM results indicated that the surface of insoluble dietary fiber(IDF)was porous,while the soluble dietary fiber(SDF)was relatively compact and spongy.IDF exhibited significantly higher water holding,oil holding,and swelling binding capacities than the corresponding SDF.However,SDF exhibited significantly higher viscosity than IDF.The results showed tremella dietary fibers were significant in swelling,water holding and oil holding,cholesterol and bile acids.In vivo experiment results in mice indicated that SDF has the best effect on hyperlipidemia mice than IDF and total dietary fiber(TDF).SDF showed that the total cholesterol(TC),triglyceride(TG)and low density lipoprotein cholesterol(LDL-C)contents dropped by 28.33%,18.65%,and 48.97%,respectively,while high density lipoprotein cholesterol(HDL-C)content increased by 43.80%.Compared with the high-fat control(HCM)group,the arteriosclerosis index(AI)and liver index(LI)of the SDF group mice showed significant differences,indicating that SDF has a good auxiliary effect of lowering blood lipids.The administration of tremella fibers improved the lipid metabolism disorderly situation of hyperlipidemia mice.These results provide a reference for further research and rational development of T.fuciformis.

Green Method, Optical and Structural Characterization of ZnO Nanoparticles Synthesized Using Leaves Extract of M. oleifera

ZnO nanoparticles(ZnO-NP)present innovative optical,electrical,and magnetic properties that depend on spe-cific characteristics,e.g.,size,distribution,and morphology.Thus,these properties are essential to address various applications in areas such as electronics,medicine,energy,and others.In addition,the performance of this ZnO-NP depends of their preparation which can be done by chemical,physical,and biological methods.Meanwhile,nowadays,the main interest in developing ZnO-NP synthesis through biological methods bases on the decrease of use of toxic chemicals or energy applied to the procedures,making the process more cost-effective and environ-mentally friendly.However,the large-scale production of nanoparticles by green synthesis remains a big challenge due to the complexity of the biological extracts used in chemical reactions.That being the case,the preparation of ZnO-NP using Moringa oleifera extract as an alternative biological agent for capping and reduction in synthesis was evaluated in this work.Then,the results based on the analysis of the optical and structural characterization of the ZnO-NP obtained by employing UV-Vis,DLS,zeta potential,XRD,ATR-FTIR,and FE-SEM indicate mostly the presence of spherical nanosized material with a mean hydrodynamic diameter of 47.2 nm measured by DLS and a mean size diameter of 25 nm observed with FE-SEM technique.Furthermore,in FE-SEM images a homo-geneous dispersion and distribution is observed in the absence of agglutination,agglomeration,or generation of significant lumps of the ZnO-NP.The XRD analysis showed that heat annealing induced the crystallite size favor-ing their monocrystallinity.Those obtained data confirm the synthesis of ZnO-NP and the absence of impurities associated with organic compounds in the annealed samples.Finally,those results and low-cost production pre-sent to the synthesized ZnO-NP by this biological method as a useful material in several applications.

STRUCTURAL CHARACTERIZATION OF Pd-SnO_2/D3520 CATALYSTS

Distribution of metals on Pd-SnO2/D3520 catalysts and state of the catalystswere studied with SEM, XRD. The interactlbn between metals and supped or between Pd and Sn or Ph were studied by IR, XPS. In addition, the relationship ofthe activity for catalytic hydrogenation of the olefins and outer layer valence electrondensity of Pd was discussed. The results showed that these catalysts had suitablesurface state, the metals were uniformly dispersed on the surface layer of the suppnd. There were not obvious interaction between the metals and the supal. Therewas strong interaction between Pd and Sn (or Ph) in the catalysts. The catalytic activity for hydrogenation was related to outer layer valence electron density of Pd.

STRUCTURAL CHARACTERIZATION OF Pd-SnO_2/D_(3520) CATALYSTS

Distribution of metals on Pd - SnO_2/D_(3520) catalysts and state of the catalysts were studied with SEM, XRD. The interaction between metals and support or between Pd and Sn or Ph were studied by IR, XPS. In addition, the relationship of the activity for catalytic hydrogenation of the olefins and outer layer valence electron density Of Pd was discussed. The results showed that these catalysts had suitable surface state, the metals were uniformly dispersed on the surface layer of the suPPort. There were not obvious lute7uction between the metals and the suPPort. There was strong interaction between Pd and Sn (or Pb) in the catalysts. The catalytic activity for hydrogenation was related to outer layer silence electron density of Pd.

Structural and Chemical Characterization of the Ediacaran Embryo-Like Fossils via the Combination of 3D-XRM and FIB-SEM Approaches

The three-dimensional(3D)morphology,anatomy,and in-situ chemical composition analysis of fossils are crucial for systematic paleontology and determining their phylogenetic positions.Scanning electron microscopy(SEM)coupled with energy-dispersive X-ray spectroscopy(EDS),offers valuable structural and chemical information for the analysis of fossils.However,its primary limitation is the restriction to two-dimensional surface data,which limits the exploration of fossils’3D complexities.Conversely,3D X-ray microscopy(3D-XRM),also known as a novel form of micro-computed tomography(micro-CT)facilitates the non-destructive 3D reconstruction of fossil specimens.Nevertheless,it lacks the capability to provide in-situ compositional data.Acknowledging the constraints inherent in these individual techniques,and in response to the evolving requirements of paleontological research,this study introduces an integrated approach that combines 3D-XRM with EDS-coupled focused ion beam scanning electron microscopy(FIB-SEM).This innovative strategy is designed to synergize the advantages of both techniques,thereby addressing challenges that conventional methods cannot.It enables the rapid identification of regions of interest(ROI)within fossil specimens at micrometer resolution.Subsequently,this method collects detailed data on both 3D structures and chemical compositions at the nanometer scale for the identified ROI.This integrated approach represents a significant advancement in paleontological and geological research methodologies,promising to meet the increasing demands of these fields.

Purifi cation, characterization and hypoglycemic activity of glycoproteins obtained from pea (Pisum sativum L.)

This study aimed to isolate and characterize the structures of glycoproteins from peas and determine their hypoglycemic activity.The crude pea glycoproteins(PGP)were extracted by hot water and purified by diethylaminoethyl(DEAE)-Sepharose chromatography and Sephadex G-100 size-exclusion chromatography in sequence.Then three main fractions were obtained,namely PGP1,PGP2 and PGP3,with molecular weights of 897615,846740 and 1194692 Da,respectively.The physical and chemical properties of the three fractions were evaluated and compared by Fourier transform infrared spectroscopy(FT-IR),nuclear magnetic resonance(NMR),scanning electron microscope(SEM),high performance liquid chromatography(HPLC)and other analytical techniques.The fraction PGP2 with the highest hypoglycemic activity,was screened using the Caco-2 monolayer cell model.It can inhibit the uptake of glucose in the small intestine,as well as the activities of maltase and sucrase.After simulated gastrointestinal digestion,PGP2 signifi cantly enhanced the inhibitory effect of α-glucosidase,and slightly reduced the inhibitory ability ofα-amylase.In summary,PGP2 possessed strong hypoglycemic activity after digestion.These results indicated that PGP2 has the potential to be developed into a functional food or natural medicine for the treatment of type 2 diabetes mellitus.