Search results
Results From The WOW.Com Content Network
[citation needed] In a close-packed structure there are 4 atoms per unit cell and it will have 4 octahedral voids (1:1 ratio) and 8 tetrahedral voids (1:2 ratio) per unit cell. [1] The tetrahedral void is smaller in size and could fit an atom with a radius 0.225 times the size of the atoms making up the lattice.
Six spheres surround an octahedral voids with three spheres coming from one layer and three spheres coming from the next layer. Structures of many simple chemical compounds, for instance, are often described in terms of small atoms occupying tetrahedral or octahedral holes in closed-packed systems that are formed from larger atoms.
The tetrahedral-octahedral honeycomb can have its symmetry doubled by placing tetrahedra on the octahedral cells, creating a nonuniform honeycomb consisting of tetrahedra and octahedra (as triangular antiprisms). Its vertex figure is an order-3 truncated triakis tetrahedron.
Pancreatic polypeptide cells (PP cells), or formerly as gamma cells (γ-cells), or F cells, are cells in the pancreatic islets (Islets of Langerhans) of the pancreas. Their main role is to help synthesize and regulate the release of pancreatic polypeptide (PP) , after which they have been named.
Intraductal papillary mucinous neoplasm (IPMN) is a type of tumor that can occur within the cells of the pancreatic duct. IPMN tumors produce mucus, [1] and this mucus can form pancreatic cysts. [2] Although intraductal papillary mucinous neoplasms are benign tumors, they can progress to pancreatic cancer. [1]
Monitor peptide binds to intestinal epithelial cells and induces CCK-release, which enhances pancreatic secretion in the presence of nutritional protein in the duodenum. [5] When all nutritional protein is digested, monitor peptide is bound by trypsin and subsequently degraded, resulting in decreasing CCK-release and a reduction of pancreatic ...
Aggressive PanNET tumors have traditionally been termed "islet cell carcinoma". PanNETs are quite distinct from the usual form of pancreatic cancer, the majority of which are adenocarcinomas, which arise in the exocrine pancreas. Only 1 or 2% of clinically significant pancreas neoplasms are PanNETs. [5]
The octahedron is one of the Platonic solids, although octahedral molecules typically have an atom in their centre and no bonds between the ligand atoms. A perfect octahedron belongs to the point group O h. Examples of octahedral compounds are sulfur hexafluoride SF 6 and molybdenum hexacarbonyl Mo(CO) 6. The term "octahedral" is used somewhat ...