Zhang Jin-chi

Drought-flood abrupt alternation based on runoff in the Huaihe River Basin during rainy season

Based on the monthly runoff data during 1950-2007at Wujiadu Hydrologic Station in the Huaihe River Basin,the drought-flood abrupt alternation phenomena(including drought to flood and flood to drought) based on runoff was analyzed during the main rainy season(MJJA) by using long-and short-cycle runoff drought-flood abrupt alternation index(RDFAI).The results are as follows: 1) the frequency of long-cycle runoff drought-flood abrupt alternations was higher in the period before 1986,and then decreased after the late 1980s;2) Inter-annual changes of the short-cycle runoff drought-flood abrupt alternation phenomena between the adjacent months varied from each other,with the change between June and July being the most obvious one,and the long-term changes are similar to that of the long-cycle runoff drought-flood abrupt alternation phenomena;3) Both the occurrence of long-and short-cycle runoff drought-flood abrupt alternation phenomena showed decreasing trends during the past 57 years,however,the total drought and total flood phenomena were on the rise;4) During the 2000s,both the long-cycle and short-cycle runoff drought to flood abrupt alternation in June and July increased,and this might be one of the major reasons for the runoff increase during the rainy season at the same period.

Antheraea pernyi silk sericin mediating biomimetic nucleation and growth of hydroxylapatite crystals promoting bone matrix formation

Bone biomineralization is well‐regulated processes mediated by extracellular matrix proteins. The materials that can direct nucleation of hydroxylapatite (HAp) crystals and assembly of well‐structured material‐minerals complex are the key to mimicking the natural mineralization. This study used sericin from Antheraea pernyi (A.pernyi), non‐mulberry silkworm cocoon as template to mediate nucleation of HAp crystals. Here we find out that AS (Antheraea pernyi sericin) can nucleate the formation HAp crystals in simulated body fluid verified by XRD and FTIR observations. The HAp crystals are organized into nano‐rods oriented with c‐axis preferentially parallel to the long axis of AS due to hydrogen bonds and electrostatic interaction and finally aggregated into HAp globule. The cell culture of human bone marrow‐derived mesenchymal stem cells (BMSCs) showed that the HAp crystals mediated by AS not only stimulate cell adhesion and proliferation but also promote 0f osteogenic differentiation, suggesting that the resultant mineralized AS biomaterial has potential in promoting bone formation. Thus our work will provide significant implication on biomineralization of A. pernyi silk sericin as a potential scaffold for tissue engineering.