The temperature field distribution and thermal history of Fe-9Cr2WVTa reduced activation steel prepared by laser melting deposition(LMD)have been calculated with Gaussian and Ring laser beams,and the nucleation and gr...The temperature field distribution and thermal history of Fe-9Cr2WVTa reduced activation steel prepared by laser melting deposition(LMD)have been calculated with Gaussian and Ring laser beams,and the nucleation and growth behaviors of M_(23)C_(6)precipitates in the 1st,7th and 19th layers have been calculated using the modified classical nucleation theory and Svoboda Fischer Fratzl Kozeschnik model.The energy distribution shows W-shape with Ring laser beam while it shows V-shape with Gaussian laser beam,which results in the more uniform M_(23)C_(6)size in the same layer with Ring laser beam.Precipitates in the bottom(i.e.,the 1st layer)have the minimum size and the size increases with the layer number with Gaussian and Ring laser beams.The temperature history,the instantaneous nucleation rate and the size evolution of M_(23)C_(6)have been systematically discussed.The results indicate that the nucleation,growth and re-dissolution of precipitates in reduced activation steel depend on the amount of energy absorbed in the thermal cycle during LMD.The continuous accumulation of energy during the thermal cycle leads to larger M_(23)C_(6)at the top area.The unsteady state precipitation dynamics of M_(23)C_(6)carbides during thermal cycling are consistent with the simulation results.展开更多
Background：Seborrheic dermatitis （SD） is a common inflammatory skin condition.The etiology is unclear,although overgrowth of Malassezia on the skin has been suggested to cause SD.This study investigated whether col...Background：Seborrheic dermatitis （SD） is a common inflammatory skin condition.The etiology is unclear,although overgrowth of Malassezia on the skin has been suggested to cause SD.This study investigated whether colonization with Staphylococcus plays a role in facial SD,which was not well addressed previously.Methods：The study was conducted from September 1,2011 to February 20,2012 in the First Hospital of China Medical University.In the first phase,the study evaluated the level of transepidennal water loss （TEWL） and the number of colony-forming units （CFU） of Staphylococcus in defined skin areas of SD patients who were human immunodeficiency virus （HIV） seropositive （HIV [＋] SD [＋] group,n =13）,classical SD （HIV [-] SD [＋] group,n =24） patients,H IV seropositive-non-SD （HIV [＋] SD [-] group,n =16） patients,and healthy volunteers （HIV [-] SD [-] group,n 16）.In the second phase,we enrolled another cohort of HIV （-） SD （＋） patients who applied topical fusidic acid （n =15）,tacrolimus （n =16）,or moisturizer （n =12）.Changes in the Seborrheic Dermatitis Area Severity Index （SDASI）,TEWL,and Staphylococcus density were evaluated 2 weeks later.Comparisons of each index were performed using analysis of variance （ANOVA） and least significant difference method.Results：The level of TEWL was greater through lesional sites in the HIV （＋） SD （＋） group than that in HIV （＋） SD （-） and HIV （） SD （-） groups （95% confidence interval [CI]：18.873-47.071,P 〈 0.001 and 95% CI：28.755-55.936,P 〈 0.001,respectively）.The number of CFU of Staphylococcus was greater in the HIV （＋） SD （＋） group than that in HIV （＋） SD （-） and HIV （-） SD （-） groups （95% CI：37.487-142.744,P =0.001 and 95% CI：54.936-156.400,P 〈 0.001,respectively）.TEWL was significantly more improved in patients treated with tacrolimus and fusidic acid than that in those treated with moisturizers （95% CI：7.560 38.987,P =0.004 and 95% CI：4.659-37.619,P =0.01 1,respectively）.Topical tacrolimus and fusidic acid were significantly associated with decreased SDASI as compared with moisturizer （95% CI：0.03-0.432,P =0.025 and 95% CI：0.033 0.44,P =0.024,respectively）.Conclusions：High colonization with Staphylococcus epidermidis,along with impaired skin permeability barrier function,contributes to the occurrence of SD.展开更多
To the Editor： Vitiligo is not a fatal disease; however, it can have strong social and psychological impacts on the patients. Genetic susceptibility, autoimmunity, neural dysregulation, melanin self-destruction, and ...To the Editor： Vitiligo is not a fatal disease; however, it can have strong social and psychological impacts on the patients. Genetic susceptibility, autoimmunity, neural dysregulation, melanin self-destruction, and oxidative stress may be involved in the pathogenesis of vitiligo.展开更多
To the Editor:Metastatic melanoma is a fatal disease with rapid systemic dissemination and a 5-year survival rate of about 1 7%.[1] More than half of primary metastases involve the skin as nodal,subcutaneous,or distan...To the Editor:Metastatic melanoma is a fatal disease with rapid systemic dissemination and a 5-year survival rate of about 1 7%.[1] More than half of primary metastases involve the skin as nodal,subcutaneous,or distant metastasis.[2] Cutaneous metastases of melanoma occur relatively frequently and can arise in early-or late-stage disease,with a variable clinical appearance and pattern distribution.[3] We describe herein a patient with a large subcutaneous nodule on the arm that we initially diagnosed as a lipoma.After obtaining further clinical history and reviewing the pathologic findings after excision,the nodule was determined to represent metastatic melanoma.展开更多
To the Edteor:Squamous cell carcinoma(SCC)in the ungual apparatus is a rare neoplasm.Although it is the most prevalent malignant tumor in this region,it often presents with non-specific features that lead to misdiagno...To the Edteor:Squamous cell carcinoma(SCC)in the ungual apparatus is a rare neoplasm.Although it is the most prevalent malignant tumor in this region,it often presents with non-specific features that lead to misdiagnosis and delayed treatment.[1]Various treatments have been proposed,including Mohs micrographic surgery,wide local excision with skin grafting,and amputation of the digit.Given the rarity of the condition,there is no consensus on the optimal treatment.[2]Photodynamic therapy(PDT)has been extensively used to treat nonmelanoma skin cancers,such as actinic keratosis,basal cell carcinoma,and SCC in situ.[3]The difficult treatment of subungual SCC and the success rates of PDT for early SCC suggested that this treatment would be useful for treating the following patient,who was diagnosed with subungual SCC but refused surgery and was ultimately successfully treated with topical PDT.展开更多
Reduced activation steel was successfully fabricated by laser melting deposition employing a Gaussian and a ring-shaped laser.The microstructure evolution of the reduced activation steel was investigated using the sca...Reduced activation steel was successfully fabricated by laser melting deposition employing a Gaussian and a ring-shaped laser.The microstructure evolution of the reduced activation steel was investigated using the scanning electron microscope,transmission electron microscope and electron backscatter diffraction.The experimental results showed that the grains close to the substrate were smaller than the grains in the upper layers.Compared to those deposited using a Gaussian laser,the samples deposited using a ring-shaped laser showed a more homogeneous microstructure.Furthermore,a finite element analysis(FEA)model was applied to reveal the thermal history during laser melting deposition.The simulation results were well validated with the experimental results.FEA results indicate that the peak temperature increases and the cooling rate decreases,as the layer gets further from the substrate.Additionally,the temperature and the cooling rate resulting from the Gaussian laser model were higher at the midline of the samples and lower around the edges,whereas those of the ring-shaped laser model were consistent with both at the center and around the edges.展开更多
基金This work is supported by NSAF(Grant No.U2030102)National Natural Science Foundation of China(Grant Nos.52071124 and 51701134)State Key Laboratory of New Ceramic and Fine Processing,Tsinghua University(No.KF202115).
文摘The temperature field distribution and thermal history of Fe-9Cr2WVTa reduced activation steel prepared by laser melting deposition(LMD)have been calculated with Gaussian and Ring laser beams,and the nucleation and growth behaviors of M_(23)C_(6)precipitates in the 1st,7th and 19th layers have been calculated using the modified classical nucleation theory and Svoboda Fischer Fratzl Kozeschnik model.The energy distribution shows W-shape with Ring laser beam while it shows V-shape with Gaussian laser beam,which results in the more uniform M_(23)C_(6)size in the same layer with Ring laser beam.Precipitates in the bottom(i.e.,the 1st layer)have the minimum size and the size increases with the layer number with Gaussian and Ring laser beams.The temperature history,the instantaneous nucleation rate and the size evolution of M_(23)C_(6)have been systematically discussed.The results indicate that the nucleation,growth and re-dissolution of precipitates in reduced activation steel depend on the amount of energy absorbed in the thermal cycle during LMD.The continuous accumulation of energy during the thermal cycle leads to larger M_(23)C_(6)at the top area.The unsteady state precipitation dynamics of M_(23)C_(6)carbides during thermal cycling are consistent with the simulation results.
文摘Background：Seborrheic dermatitis （SD） is a common inflammatory skin condition.The etiology is unclear,although overgrowth of Malassezia on the skin has been suggested to cause SD.This study investigated whether colonization with Staphylococcus plays a role in facial SD,which was not well addressed previously.Methods：The study was conducted from September 1,2011 to February 20,2012 in the First Hospital of China Medical University.In the first phase,the study evaluated the level of transepidennal water loss （TEWL） and the number of colony-forming units （CFU） of Staphylococcus in defined skin areas of SD patients who were human immunodeficiency virus （HIV） seropositive （HIV [＋] SD [＋] group,n =13）,classical SD （HIV [-] SD [＋] group,n =24） patients,H IV seropositive-non-SD （HIV [＋] SD [-] group,n =16） patients,and healthy volunteers （HIV [-] SD [-] group,n 16）.In the second phase,we enrolled another cohort of HIV （-） SD （＋） patients who applied topical fusidic acid （n =15）,tacrolimus （n =16）,or moisturizer （n =12）.Changes in the Seborrheic Dermatitis Area Severity Index （SDASI）,TEWL,and Staphylococcus density were evaluated 2 weeks later.Comparisons of each index were performed using analysis of variance （ANOVA） and least significant difference method.Results：The level of TEWL was greater through lesional sites in the HIV （＋） SD （＋） group than that in HIV （＋） SD （-） and HIV （） SD （-） groups （95% confidence interval [CI]：18.873-47.071,P 〈 0.001 and 95% CI：28.755-55.936,P 〈 0.001,respectively）.The number of CFU of Staphylococcus was greater in the HIV （＋） SD （＋） group than that in HIV （＋） SD （-） and HIV （-） SD （-） groups （95% CI：37.487-142.744,P =0.001 and 95% CI：54.936-156.400,P 〈 0.001,respectively）.TEWL was significantly more improved in patients treated with tacrolimus and fusidic acid than that in those treated with moisturizers （95% CI：7.560 38.987,P =0.004 and 95% CI：4.659-37.619,P =0.01 1,respectively）.Topical tacrolimus and fusidic acid were significantly associated with decreased SDASI as compared with moisturizer （95% CI：0.03-0.432,P =0.025 and 95% CI：0.033 0.44,P =0.024,respectively）.Conclusions：High colonization with Staphylococcus epidermidis,along with impaired skin permeability barrier function,contributes to the occurrence of SD.
文摘To the Editor： Vitiligo is not a fatal disease; however, it can have strong social and psychological impacts on the patients. Genetic susceptibility, autoimmunity, neural dysregulation, melanin self-destruction, and oxidative stress may be involved in the pathogenesis of vitiligo.
文摘To the Editor:Metastatic melanoma is a fatal disease with rapid systemic dissemination and a 5-year survival rate of about 1 7%.[1] More than half of primary metastases involve the skin as nodal,subcutaneous,or distant metastasis.[2] Cutaneous metastases of melanoma occur relatively frequently and can arise in early-or late-stage disease,with a variable clinical appearance and pattern distribution.[3] We describe herein a patient with a large subcutaneous nodule on the arm that we initially diagnosed as a lipoma.After obtaining further clinical history and reviewing the pathologic findings after excision,the nodule was determined to represent metastatic melanoma.
基金supported by a grant of the National Natural Science Foundation of China(No.81903198).
文摘To the Edteor:Squamous cell carcinoma(SCC)in the ungual apparatus is a rare neoplasm.Although it is the most prevalent malignant tumor in this region,it often presents with non-specific features that lead to misdiagnosis and delayed treatment.[1]Various treatments have been proposed,including Mohs micrographic surgery,wide local excision with skin grafting,and amputation of the digit.Given the rarity of the condition,there is no consensus on the optimal treatment.[2]Photodynamic therapy(PDT)has been extensively used to treat nonmelanoma skin cancers,such as actinic keratosis,basal cell carcinoma,and SCC in situ.[3]The difficult treatment of subungual SCC and the success rates of PDT for early SCC suggested that this treatment would be useful for treating the following patient,who was diagnosed with subungual SCC but refused surgery and was ultimately successfully treated with topical PDT.
基金This work was supported financially by the National Key R&D Program of China(Grant No.2018YFB1105801)the National Natural Science Foundation of China(Grant No.51701134).
文摘Reduced activation steel was successfully fabricated by laser melting deposition employing a Gaussian and a ring-shaped laser.The microstructure evolution of the reduced activation steel was investigated using the scanning electron microscope,transmission electron microscope and electron backscatter diffraction.The experimental results showed that the grains close to the substrate were smaller than the grains in the upper layers.Compared to those deposited using a Gaussian laser,the samples deposited using a ring-shaped laser showed a more homogeneous microstructure.Furthermore,a finite element analysis(FEA)model was applied to reveal the thermal history during laser melting deposition.The simulation results were well validated with the experimental results.FEA results indicate that the peak temperature increases and the cooling rate decreases,as the layer gets further from the substrate.Additionally,the temperature and the cooling rate resulting from the Gaussian laser model were higher at the midline of the samples and lower around the edges,whereas those of the ring-shaped laser model were consistent with both at the center and around the edges.
