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The formation of a striation pattern in a thin stainless steel tube was investigated by numerical simulation during a pulsed Nd:YAG laser cutting process. The simulated results were compared with the experimental results, which were performed under the same conditions for simulation. The simulated results showed good agreement with the experimental results. Although the formation of the striation pattern was influenced by various laser parameters, the laser power density had become the most important factor in the formation of striation patterns, since the laser power density is the most influential in the heating of metal, and the striation formation is caused by the ejection of molten metal and evaporation during laser cutting process. Although a high power density resulted in clear regular striation patterns, relatively low power density caused the formation of a hot spot, which hindered the formation of regular striation patterns and caused less striation. The numerical simulation calculations can be used to predict the shape of striation patterns and to offer a way to provide a smooth cut wall.

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Background: Studies comparing long-term clinical outcomes between prediabetes and diabetes based on pre-percutaneous coronary intervention (PCI) Thrombolysis in Myocardial Infarction (TIMI) flow grade in patients with ST-segment elevation myocardial infarction (STEMI) after successful PCI with newer-generation drug-eluting stents are limited. We compared 2-year clinical outcomes of these two groups. Methods: Overall, 6448 STEMI patients were divided into two groups: pre-PCI TIMI 0/1 group (n = 4854) and pre-PCI TIMI 2/3 group (n = 1594). Subsequently, these two groups were further divided into patients with normoglycemia, prediabetes, and type 2 diabetes mellitus (T2DM). The major endpoint was the occurrence of major adverse cardiac events (MACEs), defined as all-cause death, recurrent myocardial infarction, or any repeat revascularization. Results: After adjustment, in the pre-PCI TIMI 0/1 group, the cumulative incidence of all-cause death was higher in both prediabetes (adjusted hazard ratio [aHR]: 1.633, p = 0.045) and T2DM (aHR: 2.064, p = 0.002) groups than in the normoglycemia group. In the pre-PCI TIMI 2/3 group, the cumulative incidence of any repeat revascularization was higher in both prediabetes (aHR: 2.511, p = 0.039) and T2DM (aHR: 3.156, p = 0.009) groups than in the normoglycemia group. However, in each group (pre-PCI TIMI 0/1 or 2/3), the cumulative incidences of MACEs and all other clinical outcomes were not significantly different between the prediabetes and T2DM groups. Conclusions: In this retrospective registry study, prediabetes showed worse clinical outcomes similar to those of T2DM regardless of the pre-PCI TIMI flow grade. However, further studies are warranted to confirm these results.