Assessment of shoreline alterations using a Digital Shoreline Analysis System: a case study of changes in the Yesilirmak Delta in northern Turkey from 1953 to 2017.

The aim of our study was to determine the erosion rates and shoreline changes in the Yesilirmak Delta (Delta) between the oldest available date (1953) before construction of the large-scale dams on the Yesilirmak River in northern Turkey and 2017. To clearly illustrate the impacts of the dams on the Delta, we investigated the relationship between the dams and shoreline changes. To compute the net shoreline changes and erosion rates over these 64 years, we used a Digital Shoreline Analysis System. To digitize the shoreline changes at the mouth of the Yesilirmak River, 1:25000-scaled topographic maps from 1957, panchromatic aerial photographs from 1962, a KH-9 Hexagon satellite image from 1980, an Ikonos satellite image from 2002, and a WorldView-2 satellite image from 2017 were used. The west and east sides of the river mouth were divided into six main groups and assessed. Each group included a time series for the shorelines. The groupings were based on the time series. For each group, the net shoreline change (m) was calculated using the net shoreline movement (NSM), and erosion rate (m/year) was calculated using the linear regression rate (LRR). According to NSM computations, net shoreline change varied from - 235.04 to 379.18 m. The greatest evolutions in net shoreline change were observed for group I, with a minimum of - 1101.11 m. According to LRR analysis, the calculated erosion rate varied from - 6.83 to 19.06 m/year. The greatest changes in erosion rate were observed for group II, with a minimum of - 30.63 m/year. There is a close relationship between the construction dates of the dams in the Yesilirmak Basin and the shoreline changes in the Delta.

Differential expression of miRNAs in pancreatobiliary type of periampullary adenocarcinoma and its associated stroma.

Periampullary adenocarcinomas can be of two histological subtypes, intestinal or pancreatobiliary. The latter is more frequent and aggressive, and characterized by a prominent desmoplastic stroma, which is tightly related to the biology of the cancer, including its poor response to chemotherapy. Whereas miRNAs are known to regulate various cellular processes and interactions between cells, their exact role in periampullary carcinoma remains to be characterized, especially with respect to the prominent stromal component of pancreatobiliary type cancers. The present study aimed at elucidating this role by miRNA expression profiling of the carcinomatous and stromal component in twenty periampullary adenocarcinomas of pancreatobiliary type. miRNA expression profiles were compared between carcinoma cells, stromal cells and normal tissue samples. A total of 43 miRNAs were found to be differentially expressed between carcinoma and stroma of which 11 belong to three miRNA families (miR-17, miR-15 and miR-515). The levels of expression of miRNAs miR-17, miR-20a, miR-20b, miR-223, miR-10b, miR-2964a and miR-342 were observed to be higher and miR-519e to be lower in the stromal component compared to the carcinomatous and normal components. They follow a trend where expression in stroma is highest followed by carcinoma and then normal tissue. Pathway analysis revealed that pathways regulating tumor-stroma interactions such as ECM interaction remodeling, epithelial-mesenchymal transition, focal adhesion pathway, TGF-beta, MAPK signaling, axon guidance and endocytosis were differently regulated. The miRNA-mRNA mediated interactions between carcinoma and stromal cells add new knowledge regarding tumor-stroma interactions.