A Novel Hydrolytic Product from Flesh of Mactra veneriformis and Its Bioactivities in Calcium Supplement

To prepare calcium-binding peptides, the flesh residue of Mactra Veneriformis was subjected to enzymatic hydrolysis. By comparing the capability of combining calcium of the hydrolyzates, pepsin was confirmed to be the most suitable enzyme for hydrolyzing the flesh residue to release calcium-binding peptides among the seven tested proteases. The pepsin hydrolyzate (PHM) was divided into three fractions according to the molecule weight of its composition, which ranged from 0.5 to 15 kDa. The low-molecule-weight fraction named PHM-3 had the highest capability in combining calcium. The peptides existing in the PHM-3 fraction consisted of higher contents of Glu, Ala and Leu, and could produce one type of calcium-peptide complex by powerfully chelating calcium ions. PHM-3 products could effectively increase calcium absorption and retention while they decreased the calcium excretion in animal tests. Additionally, symptoms caused by low calcium bioavailability in ovariectomized rats, such as bone mineral density reduction and mechanical strength loss could be significantly ameliorated by the hydrolytic products addition in diet.

Foaming supramolecular surfactants for gas mobility control in naturally fractured carbonate reservoirs at high temperature,salinity,and hardness

Oil production and mainte nance are essential issues in naturally fractured reservoirs because they are the largest and most productive on earth.However,they present early water and gas channeling but could be remediated by using foaming agents to control these phenomena through blocking channeling areas.In Mexico these reservoirs have pressure up to 5,500 psi,high temperature up to 200℃,salinity up to400,000 ppm,and hardness up to 250,000 ppm;due to these thermodynamic conditions,there has been no available technology to form stable enough foams.In this work,a foaming supramolecular surfactant with the capability to chelate Ca^(2+)ions is examined.As a result,surfactant monomers are bridged by captured Ca^(2+)cations leading to the formation of high-molecular-weight oligomers,which significantly increment the viscosity of the solution improving the foam stability,and since at this manner the Ca2+cations are no longer available to precipitate as components of solid salts,the foaming supramolecular surfactant also performs as antiscalant.These observations are explained through quantum theoretical modeling.The foam is stable,effectively blocking the gas channels,whereas in presence of oil the foam is broken leading the oil to pass into the wellbore.The characteristic rheological properties of the foam allow its injection into the formation at a range of flow rates,foam qualities,and shear stress to achieve the flooding and the blocking of a variety of fractured carbonate formations,and the change of the wettability of the matrix,which is a desirable behavior in a huff and puff process,as reported in a previous publication about a successful pilot test of this foam.

Foliar application of chelated sugar alcohol calcium fertilizer for regulating the growth and quality of wine grapes

The eastern foothills of Helan Mountain are a production area of high-quality wine grapes,but the low content of water-soluble calcium in the alkaline soil in this area has become an important limiting factor for the production of high-end wines.In this study,7-year-old Cabernet Sauvignon grapes grown at Lilan Winery,which is located at the eastern foot of Helan Mountain in Ningxia,China,were used to examine the effect of exogenous calcium supplementation on fruit growth and berry quality.Calcium sugar alcohol was applied as a foliar spray at 1.2 L/hm^(2)(T1),2.4 L/hm^(2)(T2),3.6 L/hm^(2)(T3),4.8 L/hm^(2)(T4),and 6.0 L/hm^(2)(T5)concentrations at the fruit expansion stage,the early stage of grape veraison,the middle stage of grape veraison,and the later stage of grape veraison.Water control was used for comparison.The results showed that foliar calcium supplementation can significantly enhance the photosynthetic characteristics of wine grape leaves,increase the chlorophyll content of leaves,and improve the quality of grape berries.Under the T3(3.6 L/hm^(2))concentration of exogenous calcium,the transverse diameter,the longitudinal diameter,and fruit shape index of grapes were the highest,which were increased by 1.71%,5.33%,and 3.92%compared to the control,respectively.The application of high calcium concentrations(T4 and T5)inhibited the physiological development of grapes.The spike length,hundred-grain weight,yield of wine grapes,sugar-acid ratio,tannin,and total phenols were the highest in the T2(2.4 L/hm^(2))treatment.The results of principal component analysis based on multiple indicators showed that foliar application of 2.4-3.6 L/hm^(2)chelated sugar alcohol calcium on the leaf surfaces of grape leaves was the most suitable for improving the physiological characteristics and berry quality of wine grapes.