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Abstract: Insulin therapy has been shown to contribute to extended glycemia remission in newly diagnosed patients with type 2 diabetes mellitus. This study investigated the effects of insulin treatment on pancreatic lipid content, and β-cell apoptosis and proliferation in glucose-intolerant rats to explore the protective role of insulin on β-cell function. A rat glucose-intolerant model was induced by streptozotocin and a high-fat diet. Plasma and pancreatic triglycerides, free fatty acids, and insulin were measured; and pancreatic β-cell cell apoptosis and proliferation were detected by a propidium iodide cell death assay and immunofluorescence for proliferating cell nuclear antigen. Relative β-cell area was determined by immunohistochemistry for insulin, whereas insulin production in pancreas was assessed by reverse transcriptase polymerase chain reaction. Islet β-cell secreting function was assessed by the index ΔI30/ΔG30. Glucose-intolerant rats had higher pancreatic lipid content, more islet β-cell apoptosis, lower β-cell proliferation, and reduced β-cell area in pancreas when compared with controls. Insulin therapy reduced blood glucose, inhibited pancreatic lipid accumulation and islet β-cell apoptosis, and increased β-cell proliferation and β-cell area in glucose-intolerant rats. Furthermore, impaired insulin secretion and insulin production in glucose-intolerant rats were improved by insulin therapy. Insulin can preserve β-cell function by protecting islets from glucotoxicity and lipotoxicity. It can also ameliorate β-cell area by enhancing β-cell proliferation and reducing β-cell apoptosis. [Copyright &y& Elsevier]

The propagation and transformation of four-petal Gaussian vortex beams in optical fractional Fourier transform system is investigated on the basis of the framework of Collins diffraction integral. The mathematical expression of propagation transformation is derived, and typical propagation and transformation characteristics are illustrated by numerical results. The effects of fractional Fourier order, beam order, vortex topological charge, beam width and lens focal length on the fractional Fourier transform of four-petal Gaussian vortex beams are discussed in detail. The four-petal Gaussian vortex beam has four petals rectangular symmetric intensity distribution in the source plane, which is different from the traditional circular symmetric vortex beam. The four-petal Gaussian vortex beam shows abundant transformation properties. The fractional Fourier transform system can be equivalent to other several optical systems, so the results obtained her e can be extended to other equivalent optical systems. [ABSTRACT FROM AUTHOR]