The aim of this work is to demonstrate high breakdown voltage and low buffer trapping in superlattice GaN-on-Silicon heterostructures for high voltage applications. To this aim, we compared two structures, one based on a step-graded (SG) buffer (reference structure), and another based on a superlattice (SL). In particular, we show that (i) the use of an SL allows us to push the vertical breakdown voltage above 1500 V on a 5 µm stack, with a simultaneous decrease in vertical leakage current, as compared to the reference GaN-based epi-structure using a thicker buffer thickness. This is ascribed to the better strain relaxation, as confirmed by X-Ray Diffraction data, and to a lower clustering of dislocations, as confirmed by Defect Selective Etching and Cathodoluminescence mappings. (ii) SL-based samples have significantly lower buffer trapping, as confirmed by substrate ramp measurements. (iii) Backgating transient analysis indicated that traps are located below the two-dimensional electron gas, and are related to CN defects. (iv) The signature of these traps is significantly reduced on devices with SL. This can be explained by the lower vertical leakage (filling of acceptors via electron injection) or by the slightly lower incorporation of C in the SL buffer, due to the slower growth process. SL-based buffers therefore represent a viable solution for the fabrication of high voltage GaN transistors on silicon substrate, and for the simultaneous reduction of trapping processes.Arrhythmias in Brugada syndrome patients originate in the right ventricular outflow tract (RVOT). Over the past few decades, the characterization of the unique anatomy and electrophysiology of the RVOT has revealed the arrhythmogenic nature of this region. However, the mechanisms that drive arrhythmias in Brugada syndrome patients remain debated as well as the exact site of their occurrence in the RVOT. Identifying the site of origin and mechanism of Brugada syndrome would greatly benefit the development of mechanism-driven treatment strategies.Acne is a skin disease common in adolescents and increasingly common in the adult population. The major pathologic events of acne vulgaris include increased sebum production, retention hyperkeratosis, carrying commensal skin microbiota, and inflammation. In recent years, more than 10,000 compounds have been isolated and identified from marine organisms. The aim of this study was to discover the potential anti-acne activity of fraction 9 + 10 (SF-E) of Sinularia flexibilis extract and six cembrene diterpenoids. #link# We found that the SF-E significantly reduced Cutibacterium acnes-induced edema in Wistar rat ears. The cembrene diterpenoids including 11-dehydrosinulariolide (SC-2), 3,48,11-bisepoxy-7-acetoxycembra-15(17)-en-1,12-olide (SC-7), and sinularin (SC-9) reduced nitric oxide (NO) production with 50% inhibitory concentration of 5.66 ± 0.19, 15.25 ± 0.25, and 3.85 ± 0.25 μM, respectively, and inducible NO synthase expression in RAW 264.7 cells. Moreover, treatment with SC-2, SC-7, and SC-9 significantly suppressed lipopolysaccharide- and heat-killed C. acnes-induced expression of proteins involved in mitogen-activated protein kinase pathway in both RAW 264.7 and HaCaT cells. After treatment with SC-2, SC-7, and SC-9, over-proliferation of HaCaT cells was significantly terminated. In summary, SC-2, SC-7, and SC-9 showed anti-inflammatory effects in RAW 264.7 cells, suggesting that these cembrene diterpenoids obtained from S. flexibilis are natural marine products with potential anti-acne activities.Long non-coding RNAs (lncRNAs) are defined as non-protein coding transcripts with a minimal length of 200 nucleotides. They are involved in various biological processes such as cell differentiation, apoptosis, as well as in pathophysiological processes. Numerous studies considered that frequently deregulated lncRNAs contribute to all hallmarks of cancer including metastasis, drug resistance, and angiogenesis. Angiogenesis, the formation of new blood vessels, is crucial for a tumor to receive sufficient amounts of nutrients and oxygen and therefore, to grow and exceed in its size over the diameter of 2 mm. In this review, the regulatory mechanisms of lncRNAs are described, which influence tumor angiogenesis by directly or indirectly regulating oncogenic pathways, interacting with other transcripts such as microRNAs (miRNAs) or modulating the tumor microenvironment. Further, angiogenic lncRNAs occurring in several cancer types such as liver, gastrointestinal cancer, or brain tumors are summarized. Growing evidence on the influence of lncRNAs on tumor angiogenesis verified these transcripts as potential predictive or diagnostic biomarkers or therapeutic targets of anti-angiogenesis treatment. However, there are https://www.selleckchem.com/products/LY315920(Varespladib).html left which are pointed out in this review, hence driving comprehensive research in this area is necessary to enable an effective use of lncRNAs as either therapeutic molecules or diagnostic targets in cancer.Stress relief treatments were carried out separately with a pneumatic chipping hammer, ultrasonic peening treatment, and heat treatment for metal active-gas welding (MAG) welded joints of 2205 duplex stainless steel. The effects of these methods on the residual stress, microstructure, mechanical properties and corrosion resistance of welded joints were studied. Results show the stress state of the weld and the surrounding area was effectively improved by the pneumatic chipping hammer and ultrasonic peening treatment, and the residual stress field of the surface layer changed from tensile stress to compressive stress. On the contrary, low-temperature stress relieving annealing had no obvious effect on stress distribution. After the pneumatic chipping hammer and ultrasonic peening treatment, the welded joints were machined and hardened. Correspondingly, strength and hardness were improved. However, the heat treatment only led to a slight decrease in strength and hardness due to the static recovery of the welded joint structure. All stress relief methods effectively improved the corrosion resistance of welded joints, with the ultrasonic peening treatment giving the best performance.
The aim of this work is to demonstrate high breakdown voltage and low buffer trapping in superlattice GaN-on-Silicon heterostructures for high voltage applications. To this aim, we compared two structures, one based on a step-graded (SG) buffer (reference structure), and another based on a superlattice (SL). In particular, we show that (i) the use of an SL allows us to push the vertical breakdown voltage above 1500 V on a 5 µm stack, with a simultaneous decrease in vertical leakage current, as compared to the reference GaN-based epi-structure using a thicker buffer thickness. This is ascribed to the better strain relaxation, as confirmed by X-Ray Diffraction data, and to a lower clustering of dislocations, as confirmed by Defect Selective Etching and Cathodoluminescence mappings. (ii) SL-based samples have significantly lower buffer trapping, as confirmed by substrate ramp measurements. (iii) Backgating transient analysis indicated that traps are located below the two-dimensional electron gas, and are related to CN defects. (iv) The signature of these traps is significantly reduced on devices with SL. This can be explained by the lower vertical leakage (filling of acceptors via electron injection) or by the slightly lower incorporation of C in the SL buffer, due to the slower growth process. SL-based buffers therefore represent a viable solution for the fabrication of high voltage GaN transistors on silicon substrate, and for the simultaneous reduction of trapping processes.Arrhythmias in Brugada syndrome patients originate in the right ventricular outflow tract (RVOT). Over the past few decades, the characterization of the unique anatomy and electrophysiology of the RVOT has revealed the arrhythmogenic nature of this region. However, the mechanisms that drive arrhythmias in Brugada syndrome patients remain debated as well as the exact site of their occurrence in the RVOT. Identifying the site of origin and mechanism of Brugada syndrome would greatly benefit the development of mechanism-driven treatment strategies.Acne is a skin disease common in adolescents and increasingly common in the adult population. The major pathologic events of acne vulgaris include increased sebum production, retention hyperkeratosis, carrying commensal skin microbiota, and inflammation. In recent years, more than 10,000 compounds have been isolated and identified from marine organisms. The aim of this study was to discover the potential anti-acne activity of fraction 9 + 10 (SF-E) of Sinularia flexibilis extract and six cembrene diterpenoids. #link# We found that the SF-E significantly reduced Cutibacterium acnes-induced edema in Wistar rat ears. The cembrene diterpenoids including 11-dehydrosinulariolide (SC-2), 3,48,11-bisepoxy-7-acetoxycembra-15(17)-en-1,12-olide (SC-7), and sinularin (SC-9) reduced nitric oxide (NO) production with 50% inhibitory concentration of 5.66 ± 0.19, 15.25 ± 0.25, and 3.85 ± 0.25 μM, respectively, and inducible NO synthase expression in RAW 264.7 cells. Moreover, treatment with SC-2, SC-7, and SC-9 significantly suppressed lipopolysaccharide- and heat-killed C. acnes-induced expression of proteins involved in mitogen-activated protein kinase pathway in both RAW 264.7 and HaCaT cells. After treatment with SC-2, SC-7, and SC-9, over-proliferation of HaCaT cells was significantly terminated. In summary, SC-2, SC-7, and SC-9 showed anti-inflammatory effects in RAW 264.7 cells, suggesting that these cembrene diterpenoids obtained from S. flexibilis are natural marine products with potential anti-acne activities.Long non-coding RNAs (lncRNAs) are defined as non-protein coding transcripts with a minimal length of 200 nucleotides. They are involved in various biological processes such as cell differentiation, apoptosis, as well as in pathophysiological processes. Numerous studies considered that frequently deregulated lncRNAs contribute to all hallmarks of cancer including metastasis, drug resistance, and angiogenesis. Angiogenesis, the formation of new blood vessels, is crucial for a tumor to receive sufficient amounts of nutrients and oxygen and therefore, to grow and exceed in its size over the diameter of 2 mm. In this review, the regulatory mechanisms of lncRNAs are described, which influence tumor angiogenesis by directly or indirectly regulating oncogenic pathways, interacting with other transcripts such as microRNAs (miRNAs) or modulating the tumor microenvironment. Further, angiogenic lncRNAs occurring in several cancer types such as liver, gastrointestinal cancer, or brain tumors are summarized. Growing evidence on the influence of lncRNAs on tumor angiogenesis verified these transcripts as potential predictive or diagnostic biomarkers or therapeutic targets of anti-angiogenesis treatment. However, there are https://www.selleckchem.com/products/LY315920(Varespladib).html left which are pointed out in this review, hence driving comprehensive research in this area is necessary to enable an effective use of lncRNAs as either therapeutic molecules or diagnostic targets in cancer.Stress relief treatments were carried out separately with a pneumatic chipping hammer, ultrasonic peening treatment, and heat treatment for metal active-gas welding (MAG) welded joints of 2205 duplex stainless steel. The effects of these methods on the residual stress, microstructure, mechanical properties and corrosion resistance of welded joints were studied. Results show the stress state of the weld and the surrounding area was effectively improved by the pneumatic chipping hammer and ultrasonic peening treatment, and the residual stress field of the surface layer changed from tensile stress to compressive stress. On the contrary, low-temperature stress relieving annealing had no obvious effect on stress distribution. After the pneumatic chipping hammer and ultrasonic peening treatment, the welded joints were machined and hardened. Correspondingly, strength and hardness were improved. However, the heat treatment only led to a slight decrease in strength and hardness due to the static recovery of the welded joint structure. All stress relief methods effectively improved the corrosion resistance of welded joints, with the ultrasonic peening treatment giving the best performance.
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