This paper proposes the‘skin effect’of the machining-induced damage at high strain rates.The paper first reviews the published research work on machining-induced damage and then identifies the governing factors that...This paper proposes the‘skin effect’of the machining-induced damage at high strain rates.The paper first reviews the published research work on machining-induced damage and then identifies the governing factors that dominate damage formation mechanisms.Among many influential factors,such as stress-strain field,temperature field,material responses to loading and loading rate,and crack initiation and propagation,strain rate is recognized as a dominant factor that can directly lead to the‘skin effect’of material damage in a loading process.The paper elucidates that material deformation at high strain rates(>103 s−1)leads to the embrittlement,which in turn contributes to the‘skin effect’of subsurface damage.The paper discusses the‘skin effect’based on the principles of dislocation kinetics and crack initiation and propagation.It provides guidance to predicting the material deformation and damage at a high strain-rate for applications ranging from the armor protection,quarrying,petroleum drilling,and high-speed machining of engineering materials(e.g.ceramics and SiC reinforced aluminum alloys).展开更多
目的探讨"工"字型DuoDERM水胶体敷料对重症监护室使用鼻塞式无创通气治疗的新生儿鼻部皮肤损伤的预防效果,为新生儿鼻部皮肤完整性的护理提供科学依据。方法便利抽样法选取2016年1-6月首都医科大学附属北京儿童医院新生儿重...目的探讨"工"字型DuoDERM水胶体敷料对重症监护室使用鼻塞式无创通气治疗的新生儿鼻部皮肤损伤的预防效果,为新生儿鼻部皮肤完整性的护理提供科学依据。方法便利抽样法选取2016年1-6月首都医科大学附属北京儿童医院新生儿重症监护室(neonatal intensive care unit,NICU)接受鼻塞式无创通气治疗的50例新生儿为研究对象。设计"工"字型DuoDERM水胶体敷料应用于患儿鼻部,目标性监测其预防患儿鼻部皮肤损伤的效果。结果患儿无1例发生鼻部皮肤损伤。结论 "工"字型DuoDERM水胶体敷料的应用不仅避免医用材料的浪费,而且制作方法简单,减轻护理工作量,可有效预防鼻部皮肤损伤,对新生儿鼻部皮肤完整性的护理有重要的临床推广意义。展开更多
Objective： To evaluate the effects of epicutaneous application of anticoagulant warfarin, by examining the presence of tissue injury and immune/inflammatory activity in exposed skin. Methods： Rats were exposed to wa...Objective： To evaluate the effects of epicutaneous application of anticoagulant warfarin, by examining the presence of tissue injury and immune/inflammatory activity in exposed skin. Methods： Rats were exposed to warfarin by applying 10 μg of warfarin‐sodium to 10‐12 cm 2 skin （range 0.8‐1 μg per 1 cm 2 ） for 3 consecutive days. Tissue injury was evaluated by lipid peroxidation, histomorphological changes and signs of reparative activity in skin. T cell infiltration and selected aspects of epidermal cell activity were examined as indicators of immune/inflammatory skin response to warfarin application. Results： Repeated warfarin application exerted no effect on skin metabolic viability, but resulted in tissue injury （increased malondialdehyde, MDA, production, evident histo‐morphological changes in epidermis and dermis depicting cell injury and death）. Increased numbers of proliferating cell nuclear antigen （PCNA ＋ ） cells indicated reparative processes in injured skin. Infiltration of CD3 ＋ cells （T lymphocytes） along with the increased production of tumor necrosis factor‐α （TNF‐α） by epidermal cells from warfarin‐treated skin and their co‐stimulatory effect in an in vitro T‐cell activation assay demonstrated immunomodulatory effects of epicutaneous warfarin. Conclusion： Presented data have documented tissue damage associated with immune/ inflammatory activity in skin exposed to warfarin. Observed effects are relevant to immunotoxic potential of this anticoagulant in settings of external exposure.展开更多
Objective: Skin damage induced by ischemia/reperfusion (I/R) is a multifactorial process that often occurs in plastic surgery. The mechanisms of I/R injury include hypoxia, inflammation, and oxidative damage. Hydrogen...Objective: Skin damage induced by ischemia/reperfusion (I/R) is a multifactorial process that often occurs in plastic surgery. The mechanisms of I/R injury include hypoxia, inflammation, and oxidative damage. Hydrogen gas has been reported to alleviate cerebral I/R injury by acting as a free radical scavenger. Here, we assessed the protective effect of hydrogen-rich saline (HRS) on skin flap I/R injury. Methods: Abdominal skin flaps of rats were elevated and ischemia was induced for 3 h; subsequently, HRS or physiological saline was administered intraperitoneally 10 min before reperfusion. On postoperative Day 5, flap survival, blood perfusion, the accumulation of reactive oxygen species (ROS), and levels of cytokines were evaluated. Histological examinations were performed to assess inflammatory cell infiltration. Results: Skin flap survival and blood flow perfusion were improved by HRS relative to the controls. The production of malondialdehyde (MDA), an indicator of lipid peroxidation, was markedly reduced. A multiplex cytokine assay revealed that HRS reduced the elevation in the levels of inflammatory cytokines, chemokines and growth factors, with the exception of RANTES (regulated on activation, normal T-cell expressed and secreted) growth factor. HRS treatment also reduced inflammatory cell infiltration induced by I/R injury. Conclusions: Our findings suggest that HRS mitigates I/R injury by decreasing inflammation and, therefore, has the potential for application as a therapy for improving skin flap survival.展开更多
基金The authors would like to acknowledge the supports by the National Natural Science Foundation of China(Grant No.51575084)and the Peacock Program of Shenzhen(Grant No.KQJSCX20180322152221965).
文摘This paper proposes the‘skin effect’of the machining-induced damage at high strain rates.The paper first reviews the published research work on machining-induced damage and then identifies the governing factors that dominate damage formation mechanisms.Among many influential factors,such as stress-strain field,temperature field,material responses to loading and loading rate,and crack initiation and propagation,strain rate is recognized as a dominant factor that can directly lead to the‘skin effect’of material damage in a loading process.The paper elucidates that material deformation at high strain rates(>103 s−1)leads to the embrittlement,which in turn contributes to the‘skin effect’of subsurface damage.The paper discusses the‘skin effect’based on the principles of dislocation kinetics and crack initiation and propagation.It provides guidance to predicting the material deformation and damage at a high strain-rate for applications ranging from the armor protection,quarrying,petroleum drilling,and high-speed machining of engineering materials(e.g.ceramics and SiC reinforced aluminum alloys).
文摘目的探讨"工"字型DuoDERM水胶体敷料对重症监护室使用鼻塞式无创通气治疗的新生儿鼻部皮肤损伤的预防效果,为新生儿鼻部皮肤完整性的护理提供科学依据。方法便利抽样法选取2016年1-6月首都医科大学附属北京儿童医院新生儿重症监护室(neonatal intensive care unit,NICU)接受鼻塞式无创通气治疗的50例新生儿为研究对象。设计"工"字型DuoDERM水胶体敷料应用于患儿鼻部,目标性监测其预防患儿鼻部皮肤损伤的效果。结果患儿无1例发生鼻部皮肤损伤。结论 "工"字型DuoDERM水胶体敷料的应用不仅避免医用材料的浪费,而且制作方法简单,减轻护理工作量,可有效预防鼻部皮肤损伤,对新生儿鼻部皮肤完整性的护理有重要的临床推广意义。
基金supported by the Ministry of Science and Technological Development of the Republic of Serbia, Grant # 143038
文摘Objective： To evaluate the effects of epicutaneous application of anticoagulant warfarin, by examining the presence of tissue injury and immune/inflammatory activity in exposed skin. Methods： Rats were exposed to warfarin by applying 10 μg of warfarin‐sodium to 10‐12 cm 2 skin （range 0.8‐1 μg per 1 cm 2 ） for 3 consecutive days. Tissue injury was evaluated by lipid peroxidation, histomorphological changes and signs of reparative activity in skin. T cell infiltration and selected aspects of epidermal cell activity were examined as indicators of immune/inflammatory skin response to warfarin application. Results： Repeated warfarin application exerted no effect on skin metabolic viability, but resulted in tissue injury （increased malondialdehyde, MDA, production, evident histo‐morphological changes in epidermis and dermis depicting cell injury and death）. Increased numbers of proliferating cell nuclear antigen （PCNA ＋ ） cells indicated reparative processes in injured skin. Infiltration of CD3 ＋ cells （T lymphocytes） along with the increased production of tumor necrosis factor‐α （TNF‐α） by epidermal cells from warfarin‐treated skin and their co‐stimulatory effect in an in vitro T‐cell activation assay demonstrated immunomodulatory effects of epicutaneous warfarin. Conclusion： Presented data have documented tissue damage associated with immune/ inflammatory activity in skin exposed to warfarin. Observed effects are relevant to immunotoxic potential of this anticoagulant in settings of external exposure.
基金Project (No. 7132169) supported by the Beijing Natural Science Foundation, China
文摘Objective: Skin damage induced by ischemia/reperfusion (I/R) is a multifactorial process that often occurs in plastic surgery. The mechanisms of I/R injury include hypoxia, inflammation, and oxidative damage. Hydrogen gas has been reported to alleviate cerebral I/R injury by acting as a free radical scavenger. Here, we assessed the protective effect of hydrogen-rich saline (HRS) on skin flap I/R injury. Methods: Abdominal skin flaps of rats were elevated and ischemia was induced for 3 h; subsequently, HRS or physiological saline was administered intraperitoneally 10 min before reperfusion. On postoperative Day 5, flap survival, blood perfusion, the accumulation of reactive oxygen species (ROS), and levels of cytokines were evaluated. Histological examinations were performed to assess inflammatory cell infiltration. Results: Skin flap survival and blood flow perfusion were improved by HRS relative to the controls. The production of malondialdehyde (MDA), an indicator of lipid peroxidation, was markedly reduced. A multiplex cytokine assay revealed that HRS reduced the elevation in the levels of inflammatory cytokines, chemokines and growth factors, with the exception of RANTES (regulated on activation, normal T-cell expressed and secreted) growth factor. HRS treatment also reduced inflammatory cell infiltration induced by I/R injury. Conclusions: Our findings suggest that HRS mitigates I/R injury by decreasing inflammation and, therefore, has the potential for application as a therapy for improving skin flap survival.
