ABSTRACT
Objective:To investigate the value of 3D printing technology in sphenoid ridge meningioma dissection. Methods:By using craniocerebral spiral enhanced CT scan DICOM images, the skull, vessels, and tumor were extracted, reconstructed, and assembled and integrated in the same coordinate system. Then, we constructed a 3D virtual model and a 3D-printed entity model, which was ap-plied for preoperation and postoperation. Results:Virtual models of the brains of five patients were reconstructed successfully and 3D entity models were produced. The models expressed the relationship among tumors, adjacent blood vessels, and the important posi-tion of the nerve tissue. Then, the models were applied to the reference before surgery planning and after surgery. Five cases were successfully performed. Conclusion:The use of the entity model of sphenoid ridge meningioma is important in optimizing operation plans, improving tumor resection, and reducing intraoperative bleeding.
ABSTRACT
The impeller profile, which is one of the most important factors, determines the creation of shear stress which leads to blood hemolysis in the internal flow of centrifugal blood pump. The investigation of the internal flow field in centrifugal blood pump and the estimation of the hemolysis within different impeller profiles will provide information to improve the performance of centrifugal blood pump. The SST kappa-omega with low Reynolds correction was used in our laboratory to study the internal flow fields for four kinds of impellers of centrifugal blood pump. The flow fields included distributions of pressure field, velocity field and shear stress field. In addition, a fast numerical hemolysis approximation was adopted to calculate the normalized index of hemolysis (NIH). The results indicated that the pressure field distribution in all kinds of blood pump were reasonable, but for the log spiral impeller pump, the vortex and backflow were much lower than those of the other pumps, and the high shear stress zone was just about 0.004%, and the NIH was 0.0089.
Subject(s)
Humans , Assisted Circulation , Heart-Assist Devices , Hemolysis , Models, Theoretical , Stress, MechanicalABSTRACT
A vacuole Na+/H+ antiporter gene TaNHX2 was obtained by screening the wheat cDNA library and by the 5'-RACE method. The expression of TaNHX2 was induced in roots and leaves by treatment with NaCl, polyethylene glycol (PEG), cold and abscisic acid (ABA). When expressed in a yeast mutant (deltanhx1), TaNHX2 suppressed the salt sensitivity of the mutant,which was deficient in vacuolar Na+/H+ antiporter, and caused partial recovery of growth of delta nhx1 in NaCl and LiCl media. The survival rate of yeast cells was improved by overexpressing the TaNHX2 gene under NaCl, KCl, sorbitol and freezing stresses when compared with the control. The results imply that TaNHX2 might play an important role in salt and osmotic stress tolerance in plant cells.