ABSTRACT
In a craniotomy, the milling cutter is one of the most important cutting tools. The operating performance, tool durability and cutting damage to patients are influenced by the tool's sharpness, intensity and structure, whereas the cutting characteristics rely on interactions between the tool and the skull. In this study, an orthogonal cutting experiment during a craniotomy of fresh pig skulls was performed to investigate chip formation on the side cutting and face cutting of the skull using a high-speed camera. The cutting forces with different combinations of cutting parameters, such as the rake angle, clearance angle, depth of cut and cutting speed, were measured. The skull bone microstructure and cutting damage were observed by scanning electron microscope. Cutting models for different cutting approaches and various depths of cut were constructed and analyzed. The study demonstrated that the effects of shearing, tension and extrusion occur during chip formation. Various chip types, such as unit chips, splintering chips and continuous chips, were generated. Continuous pieces of chips, which are advisable for easy removal from the field of operation, were formed at greater depths of cut and tool rake angles greater than 10°. Cutting damage could be relieved with a faster recovery with clearance angles greater than 20°.
Subject(s)
Craniotomy/instrumentation , Mechanical Phenomena , Skull/surgery , Animals , SwineABSTRACT
Objective To explore the clinical value of glycosylated hemoglobin A1(HbA1c) ,C-reactive protein(CRP) ,interleu-kin-6(IL-6) and ischemia modified albumin(IMA) in patients with type 2 diabetes nephropathy .Methods 64 patients with type 2 diabetes mellitus were divided into simple diabetic mellitus group(34 patients) and diabetic nephropathy group(30 patients) .In ad-dition ,40 healthy subjects were chosen as control group .The levels of HbA1c ,CRP ,IL-6 and IMA were detected .Results The lev-els of HbA1c ,CRP ,IL-6 and IMA in simple diabetic mellitus group were all significantly higher than those in control group(P<0 .05) .The levels of HbA1c ,CRP ,IL-6 and IMA in diabetic nephropathy group were all significantly higher than those in simple di-abetic mellitus group(P<0 .05) .There were a positive correlations between the HbA1c level and the levels of CRP ,IL-6 ,IMA(P<0 .05) .The positive rate of combined detection of HbA1c ,CRP ,IL-6 and IMA was significantly higher than separate index detection (P<0 .05) .Conclusion The combined detection of HbA1c ,CRP ,IL-6 and IMA may be beneficial to the early diagnosis of diabetic nephropathy ,which will delay the progress of diabetic nephropathy .
