Isomerization and degradation of all-trans-β-carotene during in-vitro digestion

To investigate the behavior of all-trans-β-carotene during digestion,in-vitro digestion coupled with HPLC-DAD,Raman spectroscopy and Fourier transform-infrared spectroscopy were used to monitor it.All-trans-β-carotene reduced by 75%during the in-vitro digestion and had a highest degradation during intestinal digestion compared with oral and gastro digestion.All-trans-β-carotene occurred isomerization and degradation during oral digestion and occurred degradation during gastro and intestinal digestion.Isomers were identifi ed as 15-cis-β-carotene and 9-cis-β-carotene,degradation products were compounds with function group of C—O,C—O—C or C=C—C=C.The biological fate ofβ-carotene during digestion was clarifi ed,and one of the reasons for low bioavailability ofβ-carotene was explained by high degradation rate during digestion.

An estimation of groundwater storage variations from GRACE gravity satellites in the Heihe River Basin, northwestern China

There are only limited surface water resources available in the Heihe River Basin （HRB）, a typical inland river basin in the arid region of northwestern China, where groundwater overexploitation is a serious problem. Groundwater has become one of main resources of fresh water in the HRB. In this paper, temporal and spatial variations of groundwater in the HRB are estimated by the Gravity Recovery and Climate Experiment （GRACE） satellites. Our analysis shows that groundwater storage in the HRB reaches its highest in the summer of 2005, and then begins to decline in the following years and reaches steady status in 2008. Spatially, groundwater shows a decline in the upper HRB in the first two years and a slight increase in the following years, while this phenomenon is reversed in the middle HRB where groundwater slightly increases in 2005 and then declines in the following three years. In the lower HRB, GRACE detects a continual increase in the full six-year period. This approach is proven successful when employed in the HRB and thus offers a new insight into monitoring groundwater variations in a river basin with limited or even without any observed data.

Regional stretch method to measure the elastic and hyperelastic properties of soft materials

soft materials;;hyperelasticity;;adhesion;;dimensional analysis;;inverse

Spatiotemporal changes in terrestrial water storage in the Beijing-Tianjin Sandstorm Source Region from GRACE satellites

The Sandstorm Source Control Project in and around the Beijing-Tianjin region was one of the most important ecological projects in China.Terrestrial water storage(TWS)has important impacts on the ecological construction,agriculture,industry,and resident's lives.Based on the Gravity Recovery and Climate Experiment(GRACE)data,meteorological and Moderate Resolution Imaging Spectroradiometer(MODIS)data,etc.,this paper analyzed spatiotemporal characteristics of TWS,groundwater storage,and precipitation,and explored the influencing factors of regional TWS combined with land use and land cover(LULC),social and economic data.The most important results were as follows:(1)From 2003 to 2016,TWS in the Beijing-Tianjin Sandstorm Source Region showed a decreasing trend with a rate of 3.14 mm yr-1.(2)The TWS decline was caused mainly by groundwater overexploitation,but not pre-cipitation variation.(3)Spatiotemporal variations of TWS were related to LULC.The area with the most serious decrease of TWS was mainly located in the southwestern part of the region,where farmland percentage and population density were greater.(4)Reducing the percent of farmland and tree planting,and adding the shrub and grass planting,could be a viable choice for the Beijing-Tianjin Sandstorm Source Control Project.These results provide a scientific basis for regional water resource and ecological management.

BIOMECHANICAL MODELING OF SURFACE WRINKLING OF SOFT TISSUES WITH GROWTH-DEPENDENT MECHANICAL PROPERTIES

This paper explores growth induced morphological instabilities in biological soft materials. In view of that the growth of a living tissue not only changes its geometry but also can alter its mechanical properties, we suggest a refined volumetric growth model incorporating the effects of growth on the mechanical properties of materials. Analogy between this volumetric growth model and the conventional thermal stress model is addressed for both small and finite de- formation problems, which brings great ease for the finite element analysis based on the suggested model. Examples of growth induced surface wrinkling behavior in soft composites, including core- shell soft cylinders and three-layered soft tissues, are explored. The results and discussions foresee possible applications of the model in understanding the correlation between the morphogenesis and growth of soft biological tissues （e.g. skins and tumors）, as well as in evaluating the defor- mation and surface instability behavior of soft artificial materials induced by swelling/shrinkage.