A comparison study on structure-function relationship of polysaccharides obtained from sea buckthorn berries using different methods:antioxidant and bile acid-binding capacity

In this study,the structural characters,antioxidant activities and bile acid-binding ability of sea buckthorn polysaccharides(HRPs)obtained by the commonly used hot water(HRP-W),pressurized hot water(HRP-H),ultrasonic(HRP-U),acid(HRP-C)and alkali(HRP-A)assisted extraction methods were investigated.The results demonstrated that extraction methods had significant effects on extraction yield,monosaccharide composition,molecular weight,particle size,triple-helical structure,and surface morphology of HRPs except for the major linkage bands.Thermogravimetric analysis showed that HRP-U with filamentous reticular microstructure exhibited better thermal stability.The HRP-A with the lowest molecular weight and highest arabinose content possessed the best antioxidant activities.Moreover,the rheological analysis indicated that HRPs with higher galacturonic acid content and molecular weight showed higher viscosity and stronger crosslinking network(HRP-C,HRP-W and HRP-U),which exhibited stronger bile acid binding capacity.The present findings provide scientific evidence in the preparation technology of sea buckthorn polysaccharides with good antioxidant and bile acid binding capacity which are related to the structure affected by the extraction methods.

INITIAL BINDING CAPACTIES OF CHLORIDE ION OF COMPONENTS IN HIGH-PERFORMANCE CONCRETE

An investigation is reported on the influence of different components of high performance concrete (HPC) on the initial binding capacities (IBC) of chloride ion. The testing results demonstrate that cement has the largest IBC, and the relative binding ratio is as high as 30% of total ion amount. Among the mineral admixtures, fly ash has the largest IBC of chloride ion. The IBC of silica fume is about 14.4%, which is smaller than that of fly ash. The IBC of refined ground blast-furnace slag (microslag) is abnormal due to the influence of sulfate ion contained. The addition of superplasticizer and corrosion inhibitor containing calcium nitrite weakens the IBC of mixtures. The fluidity and pore-filling effect of mineral admixtures are studied with paste samples with WIC ratio of 0.3. The influence mechanism of various components in high-performance concrete in IBC is studied further through SEM and Mercury Instrusion Porosimetry tests with paste samples at the age of 3 days.

Protein A-based ligands for affinity chromatography of antibodies

Protein A chromatography is a key technology in the industrial production of antibodies,and a variety of commercial protein A adsorbents are available in shelf.High stability and binding capacity of a protein A adsorbent are two key issues for successful practice of protein A chromatography.Earlier versions of protein A adsorbents ever exhibited serious fragility to typical cleaning-in-place protocols(e.g.washing with sodium hydroxide solution),and suffered from low binding capacity,harsh elution,ligand leakage and other problems involved in industrial applications.During the last three decades,various techniques and approaches have been applied in the improvement of chemical stability and enhancement of binding capacity of protein A-based ligands and adsorbents for antibody purifications.This mini-review focuses on the technical explorations in protein A-based affinity adsorbents,especially protein A-based ligands,including the efforts to increase the chemical stability by site-directed mutations and to improve the binding capacity by ligand polymerization and site-directed immobilization.Moreover,the efforts to develop short peptide ligands based on the structure of protein A,including the biomimetic design strategies and the synthesis of peptide-mixed mode hybrid ligands are discussed.These peptide and peptidebased hybrid ligands exhibit high affinity and selectivity to antibodies,but noteworthy differences in the binding mechanism of antibody from protein A.As a result,bound antibody to the ligands could be effectively eluted under mild conditions.Perspectives for the development of the protein A-based peptide ligands have been extensively discussed,suggesting that the ligands represent a direction for technological development of antibody purification.

Effects of Steam Curing on the Resistance of Cementitious Materials to Chloride Penetration

The resistance to chloride penetration of cement-based material with different curing regimes was investigated by solution titration,XRD,LF-NMR and rapid chloride migration test.The results show that the curing regime has influences on the types and structure of the hydration products,which in turn affects their ability to bind chloride ions.The binding capacity of cementitious materials to chloride ions,porosity and chloride ion migration coefficient increased with the increase of water-cement ratio,while steam curing increased the porosity and chloride ion migration coefficient at the same time as it increased the chloride ion binding capacity of the materials.At lower water-cement ratios,the effect of steam curing on the resistance of cementitious materials to chloride ingress is negligible.

Assessment of Iron Profile among Transfused Dependent Chronic Renal Failure Sudanese Patients

Background: Anemia is one of the complications of chronic kidney disease (CKD) which necessitates multiple blood transfusions. These multiple transfusions are usually accompanied by Iron over load. The current study aimed to assess the Iron profile in Sudanese patients with chronic renal failure received regular blood transfused. Materials and Methods: A descriptive analytical case control study was performed in Alturki Teaching Hospital, Khartoum, Sudan. A total of 90 Sudanese were enrolled in this study (30 CKD patients under hemodialysis and undergo multiple blood transfusion, 30 CKD patients under hemodialysis but not blood transfusion and 30 healthy controls, 51 (57%) were male and 39 (43%) were females, their age ranged between 28 to 75 years. Iron profile (serum iron, serum ferritin and total iron binding capacity (TIBC)) were measured using full automated Chemical analyzer Mindray BS 200 (China). Data were analyzed by using statistical package for social sciences (SPSS) verssion16. Results: The present study showed that serum iron and serum ferritin of those under hemodialysis and received regular blood transfusion patient were significantly higher compared to those under hemodialysis and did not received regular blood transfusion patients (P value 0.000 and 0.01) respectively. Conclusion: Patients with chronic renal failure and under hemodialysis and receive regular and multiple transfusions are prone to iron overload.

Protein adsorption in two-dimensional electrochromatography packed with superporous and microporous cellulose beads

Anion-exchange superporous cellulose(DEAE-SC)and microporous cellulose(DEAE-MC)adsorbents were packed in an electrochromatographic column,and the effect of external electric field(eEF)on the dynamic adsorption was investigated.The column was designed to provide longitudinal,transverse or 2-dimensional(2D)eEF.It was found that the electro-kinetic effect caused by the introduction of an electric field played an important role in the dynamic adsorption of bovine serum albumin to the adsorbents.The dynamic binding capacity(DBC)in the presence of 2D eEF was higher than in the presence of a one-dimensional eEF.The effect of flow velocity on the DBC of the two adsorbents was also demonstrated.It was found that the effect of electric field on the DEAE-MC column was more remarkable than that on the DEAE-SC column at the same flow rate,whereas the DEAE-SC column showed higher DBC and adsorption efficiency(AE)than the DEAE-MC column.With increasing flow rate,the DEAE-SC column could still offer high DBC and AE in the presence of the 2D eEF.For example,a DBC of 21.4mg/mL and an AE of 57.7%were obtained even at a flow rate as high as 900cm/h.The results indicate that the 2D electrochromatography packed with the superporous cellulose adsorbent is promising for high-speed protein chromatography.