In this paper,the dust particle surface potential for argon-helium plasma is evaluated analytically and numerically in the context of negatively charged dust particles by employing a power-law(r,q)-distribution functi...In this paper,the dust particle surface potential for argon-helium plasma is evaluated analytically and numerically in the context of negatively charged dust particles by employing a power-law(r,q)-distribution function.Recent studies have reported the argon-helium plasma and conducted a brief theoretical and experimental survey.To deepen our understanding further,this study aims to analyze the argon-helium plasma comprehensively using the same pattern but with the(r,q)-distribution function.For this purpose,the current balance equations are derived for electron,helium and argon ions,when these charge species attain the quasineutrality condition.We numerically examined the currents of plasma species for a broad range of effective distribution function parameters r and q.It is revealed that the surface potential of dust particles is significantly affected by the parameters r and q,helium ion-to-electron temperature ratio,argon ion-to-electron temperature ratio,and helium ion to argon ion number density ratio.By incorporating the multi-ion(argon-helium)species,the significance of low-temperature nonMaxwellian dusty(complex)plasma is briefly examined.展开更多
BACKGROUND The incidence of Barrett’s esophagus(BE)in China is lower compared to the Western populations.Hence,studies conducted in the Chinese population has been limited.The current treatment options available for ...BACKGROUND The incidence of Barrett’s esophagus(BE)in China is lower compared to the Western populations.Hence,studies conducted in the Chinese population has been limited.The current treatment options available for BE treatment includes argon plasma coagulation(APC),radiofrequency ablation and cryoablation,all with varying degrees of success.AIM To determine the efficacy and safety of HybridAPC in the treatment of BE.METHODS The study cohort consisted of patients with BE who underwent HybridAPC ablation treatment.These procedures were performed by seven endoscopists from different tertiary hospitals.The duration of the procedure,curative rate,complications and recurrent rate by 1-year follow-up were recorded.RESULTS Eighty individuals were enrolled for treatment from July 2017 to June 2020,comprising of 39 males and 41 females with a median age of 54 years(range,30 to 83 years).The technical success rate of HybridAPC was 100%and the overall curative rate was 98.15%.No severe complications occurred during the operation.BE cases were classified as short-segment BE and long-segment BE.Patients with short-segment BE were all considered cured without complications.Thirty-six patients completed the one-year follow-up without recurrence.Twenty-four percent had mild dysplasia which were all resolved with one post-procedural treatment.The mean duration of the procedure was 10.94±6.52 min.CONCLUSION Treatment of BE with HybridAPC was found to be a simple and quick procedure that is safe and effective during the short-term follow-up,especially in cases of short-segment BE.This technique could be considered as a feasible alternative ablation therapy for BE.展开更多
Introduction: There are many types of retinal lesions: exudative, degenerative and post-traumatic. Some can lead to retinal detachment (RD). The treatment indicated for these neovascular diseases of the eye is retinal...Introduction: There are many types of retinal lesions: exudative, degenerative and post-traumatic. Some can lead to retinal detachment (RD). The treatment indicated for these neovascular diseases of the eye is retinal photocoagulation with the Argon laser. The aim of this study was to investigate retinal lesions treated with the Argon laser at IOTA University Hospital. Patients and Method: This was a prospective cross-sectional study over a 9-month period. All patients seen at CHU IOTA during our study period who presented with a retinal pathology treated with the Argon laser or a retinal detachment with a giant tear in the contralateral eye and who had given their consent were included. One session consisted of treating the maximum surface area of half a retina. Results: We collected 263 cases. The age group 40 to 60 years was the most represented with 48.7%. Diabetes was the most frequent antecedent with 47.1%. Neovessels were the most common type of lesion, accounting for 68.4% of cases. Pan-retinal photocoagulation was performed in 74.5% of patients. Conclusion: Retinal lesions represent a major risk of functional visual loss. Physical treatment with retinal photocoagulation has a curative effect on ischaemic lesions and a preventive effect on retinal detachment.展开更多
Subepithelial lesions(SEL)of the digestive tract refer to a series of benign and malignant subepithelial masses that appear smooth or rough under gastrointestinal endoscopy.Endoscopic resection of subepithelial lesion...Subepithelial lesions(SEL)of the digestive tract refer to a series of benign and malignant subepithelial masses that appear smooth or rough under gastrointestinal endoscopy.Endoscopic resection of subepithelial lesions in the digestive tract is widely recognized due to its advantages of minimal trauma and rapid recovery.This paper reports and summarizes the experiences of using the combined snare,long lucency cap,and argon plasma coagulation technique to remove small subepithelial lesions in 14 patients.展开更多
Jargon in English language, part of culture, is a sub-culture. This paper illustrates its connotation, original facts, constructions, functions and characteristics. This study helps us fully recognize British and Amer...Jargon in English language, part of culture, is a sub-culture. This paper illustrates its connotation, original facts, constructions, functions and characteristics. This study helps us fully recognize British and American societies from another angle, and understand diversity of their cultures to benefit English teaching and intercultural communication.展开更多
The purpose of this research was to study the effect of Argon inert gas on the laser welding quality of Co-Cr and Ni-Cr base metal alloys, which are widely used as Fixed Prosthodontics alloys in Dental Laboratories. A...The purpose of this research was to study the effect of Argon inert gas on the laser welding quality of Co-Cr and Ni-Cr base metal alloys, which are widely used as Fixed Prosthodontics alloys in Dental Laboratories. A total of 36 specimens were manufactured (18 of Ni-Cr alloy and 18 of Co-Cr alloy). The specimens were then divided into 3 subgroups (6 specimens each): control;argon-welded;and non-Argon welded. The specimens were cut, laser welded, radiographed and finally tested under tensile strength testing, followed by examination using Scanning Electron Microscopy. The tensile strength of welded specimens was lower than the strength of non-welded specimens, however this difference was not found to be statistically significant. The material factor (Co-Cr alloy or Ni-Cr alloy) has a statistically significant effect on the tensile strength, while the presence or not of the inert gas, as well as the combination of the two factors do not have a statistically significant effect. The laser welding process applied in daily practice (separation of specimen, formation of two cones in contact, aggregation of two cones, filling of the remaining gap by welding) is considered satisfactory in terms of weld strength. The factor of the material, as an independent factor, affects the tensile strength to a statistically significant degree, in contrast to the factor of the presence of inert gas which does not affect to a statistically significant degree.展开更多
BACKGROUND Chronic radiation proctitis(CRP) is a complication which occurs in 1%-5% of patients who undergo radiotherapy for pelvic malignancies. Although a wide range of therapeutic modalities are available, there is...BACKGROUND Chronic radiation proctitis(CRP) is a complication which occurs in 1%-5% of patients who undergo radiotherapy for pelvic malignancies. Although a wide range of therapeutic modalities are available, there is no literature to date showing any particularly appropriate therapeutic modality for each disease stage. Argon plasma coagulation(APC) is currently recommended as the firstchoice treatment for hemorrhagic CRP, however, its indication based on longterm follow-up is still unclear. On the hypothesis that the long-term efficacy and safety of APC are not fully understood, we reviewed APC treatment for patients with hemorrhagic CRP from a single center.AIM To assess the long-term efficacy and safety of APC for hemorrhagic CRP.METHODS This is a retrospective study of consecutive patients treated with APC for hemorrhagic CRP from January 2013 to October 2017. Demographics, clinical variables, and typical endoscopic features were recorded independently. Success was defined as either cessation of bleeding or only occasional traces of bloody stools with no further treatments for at least 12 mo after the last APC treatment.We performed univariate and multivariate analyses to identify factors associated with success and risk factors for fistulas.RESULTS Forty-five patients with a median follow-up period of 24 mo(range: 12-67 mo)were enrolled. Fifteen(33.3%) patients required blood transfusion before APC.Successful treatment with APC was achieved in 31(68.9%) patients. The mean number of APC sessions was 1.3(1-3). Multivariate analysis showed that APC failure was independently associated with telangiectasias present on more than50% of the surface area [odds ratio(OR) = 6.53, 95% confidence interval(CI): 1.09-39.19, P = 0.04] and ulcerated area greater than 1 cm^2(OR = 8.15, 95%CI: 1.63-40.88, P = 0.01). Six(13.3%) patients had severe complications involving rectal fistulation. The only factor significantly associated with severe complications was ulcerated area greater than 1 cm^2(P = 0.035).CONCLUSION The long-term efficacy of APC for hemorrhagic CRP is uncertain in patients with telangiectasias present on > 50% of the surface area and ulceration > 1 cm^2.展开更多
Based on the isotopic chronologic results of Cenozoic alkali basalts from the South China Sea, the characteristics of volcanic activi- ty of the South China Sea after spreading were studied. The potassium - argon ages...Based on the isotopic chronologic results of Cenozoic alkali basalts from the South China Sea, the characteristics of volcanic activi- ty of the South China Sea after spreading were studied. The potassium - argon ages of eight alkali basalt samples from the South China Sea, and the argon - argon ages of two samples among them are reported. Apparent ages of the whole rock are 3.80 to 7. 91 Ma with an average value of 5.43 Ma （potassium- argon, whole rock）, and there is little difference among samples at the same location, e. g. , 4. 76 - 5.78 Ma for location S（M-12. The argon - argon ages for the two samples are 6.06 and 4. 71 Ma, which lie within the age scope of potassium - argon method. The dating results indicate that rock-forming age is from late Miocene to Pliocene, which is consistent with erupting event for alkali basalts from adjacent regions of the South China Sea. Volcanic activities occur after the cessation of spreading of the South China Sea, which are controlled by lithospheric fault and the spreading center formed during the spreading period of the South China Sea. These dating results, combined with geochemical characteristics of these basalts, the published chronological data for the South China Sea and its adjacent regions, and the updated geophysical data near Hainan Island, suggest that after the cessation of spreading of the South China Sea, there occur widely distributing magmatic activities which primarily is alkali basalt, and the volcanic activity continues to Quaternary. The activity may be relative to Hainan mantle plume originated from core/mantle boundary.展开更多
The flow field of molten steel and the interfacial behaviour between molten steel and liquid slag layer in medium-thin slab continuous casting mold with argon gas injection were studied by numerical simulation, in whi...The flow field of molten steel and the interfacial behaviour between molten steel and liquid slag layer in medium-thin slab continuous casting mold with argon gas injection were studied by numerical simulation, in which the effects of nozzle submergence depth and port angle, casting speed, and argon gas flow rate on the flow and the level fluctuation of molten steel were considered. The results show that the molten steel is jetted from the submerged en- try nozzle （SEN） with three ports into the mold and forms three recirculation zones including one upper recireulation zone and two lower recirculation zones. Argon gas injection results in a secondary vortex flow in the upper zone near the nozzle. For a given casting speed and argon gas flow rate, increasing the side port angle and submergence depth of nozzle can effectively restrain the steel/slag interracial fluctuation. Increasing the casting speed would prick up the level fluctuation. For a fixed casting speed, argon gas flow rate has a critical value, the interracial fluctuation with argon gas injection are stronger than the case without argon gas injection when the argon gas flow rate is less than the critical value, but when the argon gas flow rate exceeds the critical value, the level fluctuation is calmer than that without argon gas injection.展开更多
AIM: To report the long-term outcome of patients after complete ablation of non-neoplastic Barrett's esophagus (BE) with respect to BE relapse and development of intraepithelial neoplasia or esophageal adenocarcin...AIM: To report the long-term outcome of patients after complete ablation of non-neoplastic Barrett's esophagus (BE) with respect to BE relapse and development of intraepithelial neoplasia or esophageal adenocarcinoma. METHODS: In 70 patients with historically proven non neoplastic BE, complete BE ablation was achieved by argon plasma coagulation (APC) and high-dose proton pump inhibitor therapy (120 mg omeprazole daily). Sixty-six patients (94.4%) underwent further surveillance endoscopy. At each surveillance endoscopy four-quadrant biopsies were taken from the neo-squamous epithelium at 2 cm intervals depending on the pre-treatment length of BE mucosa beginning at the neo-Z-line, and from any endoscopically suspicious lesion. RESULTS: The median follow-up of 66 patients was 51 mo (range 9-85 mo) giving a total of 280.5 patient years. A mean of 6 biopsies were taken during surveillance endoscopies. In 13 patients (19.7%) tongues or islands suspicious for BE were found during endoscopy. In 8 of these patients (12.1%) non-neoplastic BE relapse was confirmed histologically giving a histological relapse rate of 3% per year. In none of the patients, intraepithelial neoplasia nor an esophageal adenocarcinoma was detected. Logistic regression analysis identified endoscopic detection of islands or tongues as the only positive predictor of BE relapse (P= 0.0004). CONCLUSION: The long-term relapse rate of non neoplastic BE following complete ablation with high-power APC is low (3% per year).展开更多
The Jinding superlarge lead and zinc deposit has attracted the attention of geologists of the world and its metallogenesis has long been in dispute. This paper takes the Jinding deposit and the Baiyangping Cu-Ag-Co de...The Jinding superlarge lead and zinc deposit has attracted the attention of geologists of the world and its metallogenesis has long been in dispute. This paper takes the Jinding deposit and the Baiyangping Cu-Ag-Co deposit which was recently found at about 30 km north of Jinding as one ore belt, and, based on researches on the helium, argon, and xenon isotopic compositions of primary inclusions in ore-forming solutions of the main stage, the authors have found that the 3He/4He ratio of the ore-forming fluid is 2.7×10?6 (varying from 0.19 to 1.97 Ra), the 4He/40Ar ratio (0.24–3.12) is close to the mantle characteristic ratio, and the xenon isotopic composition and evolution show characters of the mantle xenon. The above results reveal the characteristics of mantle source and crust-mantle fluid mixing (mantle helium reaching 32%) and the metallogenic contributions of the deep processes in the Jinding-Baiyangping ore belt.展开更多
AIM: This prospective study evaluated the effectiveness of 90 W argon plasma coagulation (APC) for the ablation of Barrett's esophagus (BE) that is considered to be the main risk factor for the development of esop...AIM: This prospective study evaluated the effectiveness of 90 W argon plasma coagulation (APC) for the ablation of Barrett's esophagus (BE) that is considered to be the main risk factor for the development of esophageal adenocarcinoma.METHODS: The results from 25 patients, observed at the First Department of General Surgery, University of Verona, Italy, from October 2000 to October 2003, who underwent APC for histologically proven BE were prospectively analyzed.RESULTS: The ablation treatment was completed in all the patients but one (96%). The mean number of APC sessions needed to complete ablation was 1.6 (total number: 40). The eradication was obtained in the majority of cases by one session only (60%), two sessions were required in 24% of the cases and three or more in 16%.About 43% of the sessions were complicated. Retrosternal pain (22.5%) and fever (17.5%) were the most frequent symptoms. Only one major complication occurred, it was an hemorrhage due to ulcer formation on the treated esophagus that required urgent endoscopic sclerosis and admission. The follow-up was accomplished in all the patients with a mean period of 26.3 mo and 20 patients (84%) with a follow-up period longer than 24 mo. Only one patient showed a relapse of metaplastic mucosa 12 mo after the completion of ablation. The patient was hence re-treated and now is free from recurrence 33 mo later.CONCLUSION: High power setting (90 W) APC showed to be safe and effective. The effects persist at a mean follow-up period of two years with a comparable cost in term of complications with respect to standard power settings. Further studies with greater number of patients are required to confirm these results and to assess if ablation reduces the incidence of malignant progression.展开更多
The fluid flow and the interfacial phenomenon of slag and metal in tundish with gas blowing were studied with mathematical and physical modeling, and the effects of gas flowrate, the placement of porous beam for the g...The fluid flow and the interfacial phenomenon of slag and metal in tundish with gas blowing were studied with mathematical and physical modeling, and the effects of gas flowrate, the placement of porous beam for the generation of bubbles, and the combination of flow control devices on the flow and slag-metal interface were investigated. The results show that the position of gas bubbling has a significant effect on the flow in tundish, and the placement of porous beam and gas flowrate are the two main factors affecting the entrapment of slag in tundish. The closer the porous beam to the weir, the more reasonable is the flow, which is in favor of the control of slag entrapment in tundish.展开更多
We previously found that argon exerts its neuroprotective effect in part by inhibition of the toll-like receptors(TLR)2 and 4.The downstream transcription factors signal transducer and activator of transcription 3(STA...We previously found that argon exerts its neuroprotective effect in part by inhibition of the toll-like receptors(TLR)2 and 4.The downstream transcription factors signal transducer and activator of transcription 3(STAT3)and nuclear factor kappa B(NF-κB)are also affected by argon and may play a role in neuroprotection.It also has been demonstrated that argon treatment could mitigate brain damage,reduce excessive microglial activation,and subsequently attenuate brain inflammation.Despite intensive research,the further exact mechanism remains unclear.In this study,human neuroblastoma cells were damaged in vitro with rotenone over a period of 4 hours(to mimic cerebral ischemia and reperfusion damage),followed by a 2-hour post-conditioning with argon(75%).In a separate in vivo experiment,retinal ischemia/reperfusion injury was induced in rats by increasing intraocular pressure for 1 hour.Upon reperfusion,argon was administered by inhalation for 2 hours.Argon reduced the binding of the transcription factors signal transducer and activator of transcription 3,nuclear factor kappa B,activator protein 1,and nuclear factor erythroid 2-related factor 2,which are involved in regulation of neuronal damage.Flow cytometry analysis showed that argon downregulated the Fas ligand.Some transcription factors were regulated by toll-like receptors;therefore,their effects could be eliminated,at least in part,by the TLR2 and TLR4 inhibitor oxidized phospholipid 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphorylcholine(OxPAPC).Argon treatment reduced microglial activation after retinal ischemia/reperfusion injury.Subsequent quantitative polymerase chain reaction analysis revealed a reduction in the pro-inflammatory cytokines interleukin(IL-1α),IL-1β,IL-6,tumor necrosis factorα,and inducible nitric oxide synthase.Our results suggest that argon reduced the extent of inflammation in retinal neurons after ischemia/reperfusion injury by suppression of transcription factors crucial for microglial activation.Argon has no known side effects or narcotic properties;therefore,therapeutic use of this noble gas appears ideal for treatment of patients with neuronal damage in retinal ischemia/reperfusion injury.The animal experiments were approved by the Commission for Animal Care of the University of Freiburg(approval No.35-9185.81/G14-122)on October 19,2012.展开更多
In continuous casting,the argon blowing at the tundish upper nozzle is usually used to prevent nozzle clogging,whose effect is closely related to the migration of argon bubbles and the flow behavior of the liquid stee...In continuous casting,the argon blowing at the tundish upper nozzle is usually used to prevent nozzle clogging,whose effect is closely related to the migration of argon bubbles and the flow behavior of the liquid steel in the nozzle.Here,to investigate the effects of argon blowing at the tundish upper nozzle on multiphase flow behavior in nozzle,a threedimensional model of the tundish–nozzle–mold was established for numerical simulation.The results indicate that the argon bubbles injected from the inner wall of the tundish upper nozzle first move downward along the nozzle wall under the action of the liquid steel.As the distance from the tundish upper nozzle increases,the argon bubbles gradually diffuse to the center of the nozzle.Compared with no argon blowing,the liquid steel velocity increases in the center of the nozzle and decreases near the wall with argon blowing.With increasing the argon flow rate,the concentration of bubbles in the nozzle increases,and the process of bubble group diffusion to the center region of the nozzle speeds up.This in turn increases the liquid steel velocity at the center of the nozzle but reduces near the wall.With increasing the casting speed,the concentration of bubbles in the nozzle decreases,the length of the bubble group near the nozzle wall is extended,and the liquid steel velocity at the center region and near-wall region of the nozzle increases.The mechanism of argon blowing at the tundish upper nozzle to prevent nozzle clogging is mainly realized by the isolation effect of the argon bubble group on the inner wall of the nozzle.展开更多
文摘In this paper,the dust particle surface potential for argon-helium plasma is evaluated analytically and numerically in the context of negatively charged dust particles by employing a power-law(r,q)-distribution function.Recent studies have reported the argon-helium plasma and conducted a brief theoretical and experimental survey.To deepen our understanding further,this study aims to analyze the argon-helium plasma comprehensively using the same pattern but with the(r,q)-distribution function.For this purpose,the current balance equations are derived for electron,helium and argon ions,when these charge species attain the quasineutrality condition.We numerically examined the currents of plasma species for a broad range of effective distribution function parameters r and q.It is revealed that the surface potential of dust particles is significantly affected by the parameters r and q,helium ion-to-electron temperature ratio,argon ion-to-electron temperature ratio,and helium ion to argon ion number density ratio.By incorporating the multi-ion(argon-helium)species,the significance of low-temperature nonMaxwellian dusty(complex)plasma is briefly examined.
文摘BACKGROUND The incidence of Barrett’s esophagus(BE)in China is lower compared to the Western populations.Hence,studies conducted in the Chinese population has been limited.The current treatment options available for BE treatment includes argon plasma coagulation(APC),radiofrequency ablation and cryoablation,all with varying degrees of success.AIM To determine the efficacy and safety of HybridAPC in the treatment of BE.METHODS The study cohort consisted of patients with BE who underwent HybridAPC ablation treatment.These procedures were performed by seven endoscopists from different tertiary hospitals.The duration of the procedure,curative rate,complications and recurrent rate by 1-year follow-up were recorded.RESULTS Eighty individuals were enrolled for treatment from July 2017 to June 2020,comprising of 39 males and 41 females with a median age of 54 years(range,30 to 83 years).The technical success rate of HybridAPC was 100%and the overall curative rate was 98.15%.No severe complications occurred during the operation.BE cases were classified as short-segment BE and long-segment BE.Patients with short-segment BE were all considered cured without complications.Thirty-six patients completed the one-year follow-up without recurrence.Twenty-four percent had mild dysplasia which were all resolved with one post-procedural treatment.The mean duration of the procedure was 10.94±6.52 min.CONCLUSION Treatment of BE with HybridAPC was found to be a simple and quick procedure that is safe and effective during the short-term follow-up,especially in cases of short-segment BE.This technique could be considered as a feasible alternative ablation therapy for BE.
文摘Introduction: There are many types of retinal lesions: exudative, degenerative and post-traumatic. Some can lead to retinal detachment (RD). The treatment indicated for these neovascular diseases of the eye is retinal photocoagulation with the Argon laser. The aim of this study was to investigate retinal lesions treated with the Argon laser at IOTA University Hospital. Patients and Method: This was a prospective cross-sectional study over a 9-month period. All patients seen at CHU IOTA during our study period who presented with a retinal pathology treated with the Argon laser or a retinal detachment with a giant tear in the contralateral eye and who had given their consent were included. One session consisted of treating the maximum surface area of half a retina. Results: We collected 263 cases. The age group 40 to 60 years was the most represented with 48.7%. Diabetes was the most frequent antecedent with 47.1%. Neovessels were the most common type of lesion, accounting for 68.4% of cases. Pan-retinal photocoagulation was performed in 74.5% of patients. Conclusion: Retinal lesions represent a major risk of functional visual loss. Physical treatment with retinal photocoagulation has a curative effect on ischaemic lesions and a preventive effect on retinal detachment.
基金Bayannur City Science and Technology Plan Project(K202026)Inner Mongolia Autonomous Region Health and Wellness Science and Technology Plan Project(202201628)+2 种基金National Clinical Key Specialty Construction Project(2023)Inner Mongolia Autonomous Region Clinical Key Specialty Construction Project(2023)Bayannur City Clinical Key Specialty Construction Project(2023)。
文摘Subepithelial lesions(SEL)of the digestive tract refer to a series of benign and malignant subepithelial masses that appear smooth or rough under gastrointestinal endoscopy.Endoscopic resection of subepithelial lesions in the digestive tract is widely recognized due to its advantages of minimal trauma and rapid recovery.This paper reports and summarizes the experiences of using the combined snare,long lucency cap,and argon plasma coagulation technique to remove small subepithelial lesions in 14 patients.
文摘Jargon in English language, part of culture, is a sub-culture. This paper illustrates its connotation, original facts, constructions, functions and characteristics. This study helps us fully recognize British and American societies from another angle, and understand diversity of their cultures to benefit English teaching and intercultural communication.
文摘The purpose of this research was to study the effect of Argon inert gas on the laser welding quality of Co-Cr and Ni-Cr base metal alloys, which are widely used as Fixed Prosthodontics alloys in Dental Laboratories. A total of 36 specimens were manufactured (18 of Ni-Cr alloy and 18 of Co-Cr alloy). The specimens were then divided into 3 subgroups (6 specimens each): control;argon-welded;and non-Argon welded. The specimens were cut, laser welded, radiographed and finally tested under tensile strength testing, followed by examination using Scanning Electron Microscopy. The tensile strength of welded specimens was lower than the strength of non-welded specimens, however this difference was not found to be statistically significant. The material factor (Co-Cr alloy or Ni-Cr alloy) has a statistically significant effect on the tensile strength, while the presence or not of the inert gas, as well as the combination of the two factors do not have a statistically significant effect. The laser welding process applied in daily practice (separation of specimen, formation of two cones in contact, aggregation of two cones, filling of the remaining gap by welding) is considered satisfactory in terms of weld strength. The factor of the material, as an independent factor, affects the tensile strength to a statistically significant degree, in contrast to the factor of the presence of inert gas which does not affect to a statistically significant degree.
基金Supported by National Natural Science Foundation of China,No.81573078the National Natural Science Foundation of Guangdong Province,No.2016A030311021
文摘BACKGROUND Chronic radiation proctitis(CRP) is a complication which occurs in 1%-5% of patients who undergo radiotherapy for pelvic malignancies. Although a wide range of therapeutic modalities are available, there is no literature to date showing any particularly appropriate therapeutic modality for each disease stage. Argon plasma coagulation(APC) is currently recommended as the firstchoice treatment for hemorrhagic CRP, however, its indication based on longterm follow-up is still unclear. On the hypothesis that the long-term efficacy and safety of APC are not fully understood, we reviewed APC treatment for patients with hemorrhagic CRP from a single center.AIM To assess the long-term efficacy and safety of APC for hemorrhagic CRP.METHODS This is a retrospective study of consecutive patients treated with APC for hemorrhagic CRP from January 2013 to October 2017. Demographics, clinical variables, and typical endoscopic features were recorded independently. Success was defined as either cessation of bleeding or only occasional traces of bloody stools with no further treatments for at least 12 mo after the last APC treatment.We performed univariate and multivariate analyses to identify factors associated with success and risk factors for fistulas.RESULTS Forty-five patients with a median follow-up period of 24 mo(range: 12-67 mo)were enrolled. Fifteen(33.3%) patients required blood transfusion before APC.Successful treatment with APC was achieved in 31(68.9%) patients. The mean number of APC sessions was 1.3(1-3). Multivariate analysis showed that APC failure was independently associated with telangiectasias present on more than50% of the surface area [odds ratio(OR) = 6.53, 95% confidence interval(CI): 1.09-39.19, P = 0.04] and ulcerated area greater than 1 cm^2(OR = 8.15, 95%CI: 1.63-40.88, P = 0.01). Six(13.3%) patients had severe complications involving rectal fistulation. The only factor significantly associated with severe complications was ulcerated area greater than 1 cm^2(P = 0.035).CONCLUSION The long-term efficacy of APC for hemorrhagic CRP is uncertain in patients with telangiectasias present on > 50% of the surface area and ulceration > 1 cm^2.
基金The Special Basic Research Fund for Central Public Research Institutes (First Institute of Oceanograpgy,State Oceanic Administration)under contract No.GY02 -2008G38the Special Plan of Science and Technology Generalship in Qingdao under contract No.05-2 -JC-79the Special Project of Technical Foundational Work and Social Public Welfare Research under contract No.2003DIB3J114
文摘Based on the isotopic chronologic results of Cenozoic alkali basalts from the South China Sea, the characteristics of volcanic activi- ty of the South China Sea after spreading were studied. The potassium - argon ages of eight alkali basalt samples from the South China Sea, and the argon - argon ages of two samples among them are reported. Apparent ages of the whole rock are 3.80 to 7. 91 Ma with an average value of 5.43 Ma （potassium- argon, whole rock）, and there is little difference among samples at the same location, e. g. , 4. 76 - 5.78 Ma for location S（M-12. The argon - argon ages for the two samples are 6.06 and 4. 71 Ma, which lie within the age scope of potassium - argon method. The dating results indicate that rock-forming age is from late Miocene to Pliocene, which is consistent with erupting event for alkali basalts from adjacent regions of the South China Sea. Volcanic activities occur after the cessation of spreading of the South China Sea, which are controlled by lithospheric fault and the spreading center formed during the spreading period of the South China Sea. These dating results, combined with geochemical characteristics of these basalts, the published chronological data for the South China Sea and its adjacent regions, and the updated geophysical data near Hainan Island, suggest that after the cessation of spreading of the South China Sea, there occur widely distributing magmatic activities which primarily is alkali basalt, and the volcanic activity continues to Quaternary. The activity may be relative to Hainan mantle plume originated from core/mantle boundary.
基金Item Sponsored by National Natural Science Foundation of China and Baosteel Co(50674020)
文摘The flow field of molten steel and the interfacial behaviour between molten steel and liquid slag layer in medium-thin slab continuous casting mold with argon gas injection were studied by numerical simulation, in which the effects of nozzle submergence depth and port angle, casting speed, and argon gas flow rate on the flow and the level fluctuation of molten steel were considered. The results show that the molten steel is jetted from the submerged en- try nozzle （SEN） with three ports into the mold and forms three recirculation zones including one upper recireulation zone and two lower recirculation zones. Argon gas injection results in a secondary vortex flow in the upper zone near the nozzle. For a given casting speed and argon gas flow rate, increasing the side port angle and submergence depth of nozzle can effectively restrain the steel/slag interracial fluctuation. Increasing the casting speed would prick up the level fluctuation. For a fixed casting speed, argon gas flow rate has a critical value, the interracial fluctuation with argon gas injection are stronger than the case without argon gas injection when the argon gas flow rate is less than the critical value, but when the argon gas flow rate exceeds the critical value, the level fluctuation is calmer than that without argon gas injection.
文摘AIM: To report the long-term outcome of patients after complete ablation of non-neoplastic Barrett's esophagus (BE) with respect to BE relapse and development of intraepithelial neoplasia or esophageal adenocarcinoma. METHODS: In 70 patients with historically proven non neoplastic BE, complete BE ablation was achieved by argon plasma coagulation (APC) and high-dose proton pump inhibitor therapy (120 mg omeprazole daily). Sixty-six patients (94.4%) underwent further surveillance endoscopy. At each surveillance endoscopy four-quadrant biopsies were taken from the neo-squamous epithelium at 2 cm intervals depending on the pre-treatment length of BE mucosa beginning at the neo-Z-line, and from any endoscopically suspicious lesion. RESULTS: The median follow-up of 66 patients was 51 mo (range 9-85 mo) giving a total of 280.5 patient years. A mean of 6 biopsies were taken during surveillance endoscopies. In 13 patients (19.7%) tongues or islands suspicious for BE were found during endoscopy. In 8 of these patients (12.1%) non-neoplastic BE relapse was confirmed histologically giving a histological relapse rate of 3% per year. In none of the patients, intraepithelial neoplasia nor an esophageal adenocarcinoma was detected. Logistic regression analysis identified endoscopic detection of islands or tongues as the only positive predictor of BE relapse (P= 0.0004). CONCLUSION: The long-term relapse rate of non neoplastic BE following complete ablation with high-power APC is low (3% per year).
基金supported by the Chinese postdoctoral research fund,Major State Basic Research Program of China(G1999143201)special project of geological sciences(9801)of the State Planning Commission
文摘The Jinding superlarge lead and zinc deposit has attracted the attention of geologists of the world and its metallogenesis has long been in dispute. This paper takes the Jinding deposit and the Baiyangping Cu-Ag-Co deposit which was recently found at about 30 km north of Jinding as one ore belt, and, based on researches on the helium, argon, and xenon isotopic compositions of primary inclusions in ore-forming solutions of the main stage, the authors have found that the 3He/4He ratio of the ore-forming fluid is 2.7×10?6 (varying from 0.19 to 1.97 Ra), the 4He/40Ar ratio (0.24–3.12) is close to the mantle characteristic ratio, and the xenon isotopic composition and evolution show characters of the mantle xenon. The above results reveal the characteristics of mantle source and crust-mantle fluid mixing (mantle helium reaching 32%) and the metallogenic contributions of the deep processes in the Jinding-Baiyangping ore belt.
文摘AIM: This prospective study evaluated the effectiveness of 90 W argon plasma coagulation (APC) for the ablation of Barrett's esophagus (BE) that is considered to be the main risk factor for the development of esophageal adenocarcinoma.METHODS: The results from 25 patients, observed at the First Department of General Surgery, University of Verona, Italy, from October 2000 to October 2003, who underwent APC for histologically proven BE were prospectively analyzed.RESULTS: The ablation treatment was completed in all the patients but one (96%). The mean number of APC sessions needed to complete ablation was 1.6 (total number: 40). The eradication was obtained in the majority of cases by one session only (60%), two sessions were required in 24% of the cases and three or more in 16%.About 43% of the sessions were complicated. Retrosternal pain (22.5%) and fever (17.5%) were the most frequent symptoms. Only one major complication occurred, it was an hemorrhage due to ulcer formation on the treated esophagus that required urgent endoscopic sclerosis and admission. The follow-up was accomplished in all the patients with a mean period of 26.3 mo and 20 patients (84%) with a follow-up period longer than 24 mo. Only one patient showed a relapse of metaplastic mucosa 12 mo after the completion of ablation. The patient was hence re-treated and now is free from recurrence 33 mo later.CONCLUSION: High power setting (90 W) APC showed to be safe and effective. The effects persist at a mean follow-up period of two years with a comparable cost in term of complications with respect to standard power settings. Further studies with greater number of patients are required to confirm these results and to assess if ablation reduces the incidence of malignant progression.
基金Item Sponsored by National Natural Science Foundation of China (50674020)Program for New Century Excellent Talents in University (NCET-04-0285)
文摘The fluid flow and the interfacial phenomenon of slag and metal in tundish with gas blowing were studied with mathematical and physical modeling, and the effects of gas flowrate, the placement of porous beam for the generation of bubbles, and the combination of flow control devices on the flow and slag-metal interface were investigated. The results show that the position of gas bubbling has a significant effect on the flow in tundish, and the placement of porous beam and gas flowrate are the two main factors affecting the entrapment of slag in tundish. The closer the porous beam to the weir, the more reasonable is the flow, which is in favor of the control of slag entrapment in tundish.
基金This work was financially supported by the Department of Anesthesiology and Critical Care,Medical Center-University of Freiburg,GermanyThe article processing charge was funded by the Baden-Württemberg Ministry of Science,Research and Art and the University of Freiburg in the funding programme Open Access Publishing.
文摘We previously found that argon exerts its neuroprotective effect in part by inhibition of the toll-like receptors(TLR)2 and 4.The downstream transcription factors signal transducer and activator of transcription 3(STAT3)and nuclear factor kappa B(NF-κB)are also affected by argon and may play a role in neuroprotection.It also has been demonstrated that argon treatment could mitigate brain damage,reduce excessive microglial activation,and subsequently attenuate brain inflammation.Despite intensive research,the further exact mechanism remains unclear.In this study,human neuroblastoma cells were damaged in vitro with rotenone over a period of 4 hours(to mimic cerebral ischemia and reperfusion damage),followed by a 2-hour post-conditioning with argon(75%).In a separate in vivo experiment,retinal ischemia/reperfusion injury was induced in rats by increasing intraocular pressure for 1 hour.Upon reperfusion,argon was administered by inhalation for 2 hours.Argon reduced the binding of the transcription factors signal transducer and activator of transcription 3,nuclear factor kappa B,activator protein 1,and nuclear factor erythroid 2-related factor 2,which are involved in regulation of neuronal damage.Flow cytometry analysis showed that argon downregulated the Fas ligand.Some transcription factors were regulated by toll-like receptors;therefore,their effects could be eliminated,at least in part,by the TLR2 and TLR4 inhibitor oxidized phospholipid 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphorylcholine(OxPAPC).Argon treatment reduced microglial activation after retinal ischemia/reperfusion injury.Subsequent quantitative polymerase chain reaction analysis revealed a reduction in the pro-inflammatory cytokines interleukin(IL-1α),IL-1β,IL-6,tumor necrosis factorα,and inducible nitric oxide synthase.Our results suggest that argon reduced the extent of inflammation in retinal neurons after ischemia/reperfusion injury by suppression of transcription factors crucial for microglial activation.Argon has no known side effects or narcotic properties;therefore,therapeutic use of this noble gas appears ideal for treatment of patients with neuronal damage in retinal ischemia/reperfusion injury.The animal experiments were approved by the Commission for Animal Care of the University of Freiburg(approval No.35-9185.81/G14-122)on October 19,2012.
基金the National Natural Science Foundation of China(Nos.51874215 and 51974213).
文摘In continuous casting,the argon blowing at the tundish upper nozzle is usually used to prevent nozzle clogging,whose effect is closely related to the migration of argon bubbles and the flow behavior of the liquid steel in the nozzle.Here,to investigate the effects of argon blowing at the tundish upper nozzle on multiphase flow behavior in nozzle,a threedimensional model of the tundish–nozzle–mold was established for numerical simulation.The results indicate that the argon bubbles injected from the inner wall of the tundish upper nozzle first move downward along the nozzle wall under the action of the liquid steel.As the distance from the tundish upper nozzle increases,the argon bubbles gradually diffuse to the center of the nozzle.Compared with no argon blowing,the liquid steel velocity increases in the center of the nozzle and decreases near the wall with argon blowing.With increasing the argon flow rate,the concentration of bubbles in the nozzle increases,and the process of bubble group diffusion to the center region of the nozzle speeds up.This in turn increases the liquid steel velocity at the center of the nozzle but reduces near the wall.With increasing the casting speed,the concentration of bubbles in the nozzle decreases,the length of the bubble group near the nozzle wall is extended,and the liquid steel velocity at the center region and near-wall region of the nozzle increases.The mechanism of argon blowing at the tundish upper nozzle to prevent nozzle clogging is mainly realized by the isolation effect of the argon bubble group on the inner wall of the nozzle.
