AIM:To study the therapeutic efficacy of a new transnasal ileus tube advanced endoscopically for adhesive small bowel obstruction.METHODS:A total of 186 patients with adhesive small bowel obstruction treated from Sept...AIM:To study the therapeutic efficacy of a new transnasal ileus tube advanced endoscopically for adhesive small bowel obstruction.METHODS:A total of 186 patients with adhesive small bowel obstruction treated from September 2007 to February 2011 were enrolled into this prospective randomized controlled study.The endoscopically advanced new ileus tube was used for gastrointestinal decompression in 96 patients and ordinary nasogastric tube(NGT) was used in 90 patients.The therapeutic efficacy was compared between the two groups.RESULTS:Compared with the NGT group,the ileus tube group experienced significantly shorter time for relief of clinical symptoms and improvement in the findings of abdominal radiograph(4.1 ± 2.3 d vs 8.5 ± 5.0 d) and laboratory tests(P < 0.01).The overall effectiveness rate was up to 89.6% in the ileus tube group and 46.7% in the NGT group(P < 0.01).And 10.4% of the patients in the ileus tube group and 53.3% of the NGT group underwent surgery.For recurrent adhesive bowel obstruction,ileus tube was also significantly more effective than NGT(95.8% vs 31.6%).In the ileus tube group,the drainage output on the first day and the length of hospital stay were significantly different depending on the treatment success or failure(P < 0.05).The abdominal radiographic improvement was correlated with whether or not the patient underwent surgery.CONCLUSION:Ileus tube can be used for adhesive small bowel obstruction.Endoscopic placement of the ileus tube is convenient and worthy to be promoted despite the potential risks.展开更多
Objective To investigate the placement of a long tube into the small intestine under fluoroscopic guidance and to evaluate its decompression effect on early postoperative small bowel obstruction(EPSBO).Methods Fifty-f...Objective To investigate the placement of a long tube into the small intestine under fluoroscopic guidance and to evaluate its decompression effect on early postoperative small bowel obstruction(EPSBO).Methods Fifty-four patients with EPSBO requiring decompression between April 2010 and July 2014 were enrolled in the study.Insertion of a long tube was guided by fluoroscopy.We first used the guide wire to pass the pylorus and then used the 10 Fr feeding tube as an exchangeable tube to put the superstiff wire into the duodenum.Finally the long tube could be passed over the guide wire through the pylorus into the intestine.The total procedure time,the radiation exposure time,and the incidence of complications were evaluated.Results The long tubes passed into the jejunum on initial insertion for all patients,so the success rate of this technique was 100%.The long tube was inserted into ileum in 18 patients.The mean total procedure time was 34.4±8.6 minutes,and the mean radiation exposure time 18.9±6.8 minutes.A total of 47 patients(87%) experienced full recovery following long-tube decompression and without the need for surgical intervention.Conclusions Using the wire-exchange technique,it is easy to place a long tube into the small bowel under fluoroscopic guidance.This decompression method is safe and effective for management of EPSBO.展开更多
Thin-walled aluminum alloy tube numerical control （NC） bending with small bending radius is a complex process with multi-factor coupling effects and multi-die constraints. A significance-based optimization method of...Thin-walled aluminum alloy tube numerical control （NC） bending with small bending radius is a complex process with multi-factor coupling effects and multi-die constraints. A significance-based optimization method of the parameters was proposed based on the finite element （FE） simulation, and the significance analysis of the processing parameters on the forming quality in terms of the maximum wall thinning ratio and the maximum cross section distortion degree was implemented using the fractional factorial design. The optimum value of the significant parameter, the clearance between the tube and the wiper die, was obtained, and the values of the other parameters, including the friction coefficients and the clearances between the tube and the dies, the mandrel extension length and the boost velocity were estimated. The results are applied to aluminum alloy tube NC bending d50 mm×1 mm×75 mm and d70 mm×1.5 mm×105 mm （initial tube outside diameter D0 × initial tube wall thickness t0 × bending radius R）, and qualified tubes are produced.展开更多
AIMTo determine whether small interfering RNA (siRNA) of PGC-1α could inhibit vascular endothelial growth factor (VEGF) expression and tube formation in human retinal vascular endothelial cells (hRVECs).ME...AIMTo determine whether small interfering RNA (siRNA) of PGC-1α could inhibit vascular endothelial growth factor (VEGF) expression and tube formation in human retinal vascular endothelial cells (hRVECs).METHODShRVECs transfected with peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) siRNA were incubated for 24h and then placed into a normoxic (20%, O<sub>2</sub>) or hypoxic (1%, O<sub>2</sub>) environment for another 16h. PGC-1α mRNA and protein levels were detected by real-time PCR and Western blot. VEGF mRNA and protein levels were detected by real-time PCR and ELISA. Cell proliferation was evaluated by BrdU incorporation assay. Forty-eight hours after siRNA transfection, hRVECs were planted into Matrigel-coated plates and cultured under normoxic (20%, O<sub>2</sub>) or hypoxic (1%, O<sub>2</sub>) conditions for another 48h. The tube formation of hRVECs was observed under an optical microscope and quantified by counting the number of branch points and calculating the total tube length.RESULTSPGC-1α mRNA and protein levels were significantly reduced by PGC-1α siRNA, and VEGF mRNA and protein levels also decreased significantly. The percentage of BrdU-labeled cells in siPGC-1α groups were significantly decreased compared with control siRNA groups under normoxia and hypoxia in cell proliferation assay. In the tube formation assay, PGC-1α siRNA treated cells formed significantly fewer tubes.CONCLUSIONBlocking PGC-1α expression can inhibit VEGF expression in hRVECs and inhibit their ability to form tubes under both normoxic and hypoxic conditions.展开更多
Purpose: To evaluate the quality of three-dimensional (3D) CT angiography images of the abdominal viscera with small focal spot, low tube voltage, and iterative model reconstruction technique (IMR). Materials and Meth...Purpose: To evaluate the quality of three-dimensional (3D) CT angiography images of the abdominal viscera with small focal spot, low tube voltage, and iterative model reconstruction technique (IMR). Materials and Methods: Seven patients with suspected disease of the pancreatobiliary system had undergone CT with high-quality CTA protocol in the present study. There were 5 men and 2 women, ranging in age from 52 to 80 years (mean: 64 years). Results: Depiction of abdominal small artery, small portal vein was possible in all cases. In two cases that we were able to compare, it was superior to standard CTA in small vascular depiction in CTA made clearly in high quality protocol. Conclusions: Although the use of small focal spot, low tube voltage, and IMR can produce higher-quality images of abdominal vessels than standard CTA, this improvement is not significant at elevated radiation doses.展开更多
Currently requirements of thin-walled tube with small bending radius cause the defects such as wrinkling, overthinning and cross-section distortion more prone to occur in bending process. Based on the analysis of the ...Currently requirements of thin-walled tube with small bending radius cause the defects such as wrinkling, overthinning and cross-section distortion more prone to occur in bending process. Based on the analysis of the forming characteristics by analytical and experimental methods, a complete 3D elastic-plastic FEM model of the process was developed using ABAQUS/Explicit code, including bending process, balls retracting and unloading process, and thus the plastic deformation characteristics with small bending radius were investigated. The main results show that: 1) The utmost deformation feature of the NC bending process is its continuous progressive deformation. 2) The occurring conditions of the defects such as wrinkling and tension instability in the process are obtained. The wrinkling is traditional on the double compressive stresses state and the tension instability is on the double tension stresses state. 3) The enhanced non-uniform deformation in thin-walled tube with small bending radius is demonstrated by comparing the stress/ strains distributions under the 1.5D and 1D bending conditions. 4) For ID small bending process, a new method-'stepped mandrel retraction' is proposed to improve the bending quality in experiment according to the FE simulation. The simulation results are verified by experiment.展开更多
Numerical control(NC) bending experiments with different process parameters were carried out for 5052O aluminum alloy tubes with outer diameter of 70 mm, wall thickness of 1.5 mm, and centerline bending radius of 105 ...Numerical control(NC) bending experiments with different process parameters were carried out for 5052O aluminum alloy tubes with outer diameter of 70 mm, wall thickness of 1.5 mm, and centerline bending radius of 105 mm. And the effects of process parameters on tube wall thinning and cross section distortion were investigated. Meanwhile, acceptable bending of the 5052O aluminum tubes was accomplished based on the above experiments. The results show that the effects of process parameters on bending process for large diameter thin-walled aluminum alloy tubes are similar to those for small diameter thin-walled tubes, but the forming quality of the large diameter thin-walled aluminum alloy tubes is much more sensitive to the process parameters and thus it is more difficult to form.展开更多
Background: Accurate determination of the optimal insertion depth of a pediatric endotracheal tube (ETT) is quite important. The aim of this study was to create an easily available formula that can be used to determin...Background: Accurate determination of the optimal insertion depth of a pediatric endotracheal tube (ETT) is quite important. The aim of this study was to create an easily available formula that can be used to determine the optimal insertion depth for a cuffed ETT even without depth marking with clear definitions of the upper and lower limits for the tip of ETT in the trachea in clinical practice. Methods: Eighty children under 12 years of age were enrolled. The depth marking of the cuffed ETT was placed at the vocal cords and both lungs were then auscultated using a stethoscope. The upper limit was radiographically defined as the position of the tip of the cuffed ETT being between the clavicles. The lower limit was defined as a distance of 5 mm above the carina. The relationship between the insertion depth and patient characteristics was analyzed to create a formula for optimal ETT insertion depth. Results: Sixty-nine ETTs were optimally placed in the trachea. There were good correlations between the optimal insertion depth of ETTs and patients characteristics (height (R = 0.92);BSA (R = 0.92);weight (R = 0.91);age (R = 0.88)). Using these patient characteristics, we created the following three formulas for calculation of the optimal insertion depth for pediatric cuffed ETTs: insertion depth (cm) = height (cm)/11 + 5.5, weight (kg)/3 + 9.5 or 11 + 3/4 × age (years). The rates of appropriate tube placement of both pediatric cuffed ETTs were 87.5% (Hi-Contour) and 85.0% (Microcuff). Conclusions: Our formula and graphs may be easy to determine the optimal insertion depth of cuffed ETT even without depth marking in clinical practice.展开更多
Two-phase flow pressure drop measurements were made during the phase change heat transfer process of R22 in a small horizontal smooth tube with 2.5 mm inside diameter. Conclusions can be drawn that the quality corresp...Two-phase flow pressure drop measurements were made during the phase change heat transfer process of R22 in a small horizontal smooth tube with 2.5 mm inside diameter. Conclusions can be drawn that the quality corresponding to the pressure gradient peak value of small tubes became higher than that of large tubes. The effect of quality to pressure drop becomes weak as the mass flux increases. The experiment data were compared with the predicated values of the state-of-the-art correlations from the open literature. The comparisons between the data and the predictions indicate that most of the state-of-the-art correlations fails to predict the experimental data. Chisholm model shows a relatively better predictive ability than the other empirical correlations although it has a mean deviation of 26.7%. But the predicated values of Chisholm model are lower by 50% than the experimental data when the quality becomes larger.展开更多
Background: Surveys of pediatric endotracheal tube (ETT) management previously reported that specialists in pediatric anesthesia and intensive care medicine preferred to use uncuffed ETTs for children younger than 8 t...Background: Surveys of pediatric endotracheal tube (ETT) management previously reported that specialists in pediatric anesthesia and intensive care medicine preferred to use uncuffed ETTs for children younger than 8 to 10 years of age. The aim of this study was to reveal the most recent attitudes and clinical practices of pediatric ETT management in Japan. Methods: The attitudes and clinical practices of pediatric ETT management were investigated using the data sheets of each institution and each patient. The data sheets contained information on patient characteristics and type of hospital, surgical procedures, devices used for intubation, and ETT information including types, size, depth, intracuff pressure (ICP), interval of ICP measurement, laryngeal packing, ETT exchange, airway complications, and reintubations. Results: The response rate of this survey was 66.7%. More than half of children older than 2 years of age were intubated with cuffed ETTs;83.5% of cuffed ETTs were used with the cuffs inflated, and ICP was measured in 80.7% of cuffed ETTs. More than half of ICP measurements were only taken at the time of intubation. Post-extubation stridor was rarely observed in cuffed (0.4%) or uncuffed ETTs (1.2%). The pediatric ETT management questionnaire revealed age-based size selection, differences in pressure of air leakage between cuffed (15 - 20 cmH2O) and uncuffed ETTs (20 - 30 cmH2O) of different sizes, the depthmarking method of insertion length. Continuous measurement of ICP was not common. Conclusion: This study revealed widespread use of cuffed ETTs in children older than 2 years of age, rarely occurrence of post-extubation stridor, inflation of cuffs, and practice of ICP measurement.展开更多
BACKGROUND Early postoperative inflammatory small bowel obstruction(EPISBO)is easy to be complicated after colorectal cancer surgery.Both intestinal obstruction catheter and meglumine can treat EPISBO.AIM To investiga...BACKGROUND Early postoperative inflammatory small bowel obstruction(EPISBO)is easy to be complicated after colorectal cancer surgery.Both intestinal obstruction catheter and meglumine can treat EPISBO.AIM To investigate the efficacy of an intestinal obstruction tube combined with meg-lumine diazo in treating EPISBO of colorectal cancer.METHODS Data from 60 patients with colorectal cancer and intestinal obstruction admitted to the Proctology Department of our hospital from April 2018 to May 2022 were collected and analyzed and divided into three cohorts according to different treatment regimens.Cohort A(n=20)received a transnasal intestinal obstruction catheter with panumglumine,and cohort B(n=20)received a transnasal intestinal obstruction catheter with liquid paraffin.Cohort C(n=20)received oral treatment with meglumine.The clinical efficacy,first exhaust/defecation time,length of hospital stay,gastrointestinal decompression time,relief time of abdo-minal pain,and relief time of abdominal distension were compared among the three cohorts.The levels of C-reactive protein(CRP),tumor necrosis factor-α(TNF-α),interleukin-6(IL-6),monocyte chemotactic protein-1(MCP-1),serum albumin,and transferrin were compared among the three cohorts before and after treatment.The occurrence of adverse reactions in the three cohorts was compared.RESULTS Compared with cohort C,the successful treatment rate of cohort A was signi-ficantly higher.There were statistically significant variations in the time of first exhaust/defecation,length of hospital stays,gastrointestinal decompression time,relief time of abdominal pain,and relief time of abdominal distention among the three cohorts.Compared with cohort C,cohort A’s first exhaust/defecation time,hospitalization time,gastrointestinal decompression time,abdominal pain relief time,and abdominal distension relief time was reduced(P<0.05).After treatment,serum CRP,TNF-α,IL-6,and MCP-1 expression levels increased,and serum albumin and serum transferrin levels increased in the three cohorts.The serum albumin level in cohort A was higher than in cohort C.Compared with cohort B and cohort C,the serum transferrin level in cohort A increased(P<0.05).Compared with cohort C,the total incidence of adverse reactions in cohorts A and B was significantly higher(P<0.05).The incidence of adverse reactions was similar between cohort A and cohort B.CONCLUSION Using an ileus tube combined with meglumine diatrizoate can effectively treat postoperative inflammatory ileus obstructions after surgery colorectal cancer and improve prognosis,inflammatory response,and nutritional status.展开更多
The present study was conducted to evaluate minimally invasive tube cystostomy technique in goats and calves suffering from obstructive urolithiasis having intact and ruptured urinary bladder. This clinical study was ...The present study was conducted to evaluate minimally invasive tube cystostomy technique in goats and calves suffering from obstructive urolithiasis having intact and ruptured urinary bladder. This clinical study was carried out on 84 clinical cases （61 goats and 23 calves） based on the history, clinical signs and physical examination along with common laboratory techniques at the Chittagong Veterinary and Animal Sciences University during January 2015-December 2016. Physical parameters like heart rate, respiratory rate, rectal temperature and dehydration status of animals were noted and corrected abnormality before surgery. Some cases had slightly higher haemoglobin （Hb）, packed cell volume （PCV） and uric acid and epithelial casts in urine. The study revealed that abnormal calcium-phosphorus ratio was predisposing the animals to urolithiasis. It was found that young ruminants （3-5 months） were most commonly affected in both species. All affected animals were male in this study, in which calves were not castrated but in goats 95.08% animals were castrated. Rupture of bladder was more common in calves as compared to goats. Postoperatively all cases were administered with broad-spectrum antibiotic, anti-inflammatory agent and caliculolytic agents like ammonium chloride. Tube cystostomy with Foley’s catheter was the most satisfactory technique for the management of obstructive urolithiasis in small ruminants. Postoperative complications were recorded only in four animals and remaining 80 animals had a normal recovery from tube cystostomy. Tube cystostomy is a simple, inexpensive and very effective procedure for the treatment of urolithiasis in ruminants.展开更多
The welding temperature field and deformation of parallel arrangement small-section rectangular tubes is calculated by using a non-contact model. After comparing the computed results with the experimentally measured r...The welding temperature field and deformation of parallel arrangement small-section rectangular tubes is calculated by using a non-contact model. After comparing the computed results with the experimentally measured results, it shows that there exist big errors when applying this model to the numerical simulation of small-section rectangular tube＇ s welding temperature field and deformation. Based on a simple analysis of the errors, a contact model is presented. The heat transfer and stress analysis between small-section rectangular tubes and clamping fixture are simulated by using direct constraints method, and then the laws of the temperature distribution, which coincide with experiment, are obtained. A further numerical analysis of the stress and deformation are made, it shows that a ＂T＂ shaped stress-field is formed in the vicinity of the weld. As the stress-field departs from the centroid of tubes＇, this leads to the small rectangular tubes not only have a longitudinal deflection, but also have a transverse bending and deformation.展开更多
文摘AIM:To study the therapeutic efficacy of a new transnasal ileus tube advanced endoscopically for adhesive small bowel obstruction.METHODS:A total of 186 patients with adhesive small bowel obstruction treated from September 2007 to February 2011 were enrolled into this prospective randomized controlled study.The endoscopically advanced new ileus tube was used for gastrointestinal decompression in 96 patients and ordinary nasogastric tube(NGT) was used in 90 patients.The therapeutic efficacy was compared between the two groups.RESULTS:Compared with the NGT group,the ileus tube group experienced significantly shorter time for relief of clinical symptoms and improvement in the findings of abdominal radiograph(4.1 ± 2.3 d vs 8.5 ± 5.0 d) and laboratory tests(P < 0.01).The overall effectiveness rate was up to 89.6% in the ileus tube group and 46.7% in the NGT group(P < 0.01).And 10.4% of the patients in the ileus tube group and 53.3% of the NGT group underwent surgery.For recurrent adhesive bowel obstruction,ileus tube was also significantly more effective than NGT(95.8% vs 31.6%).In the ileus tube group,the drainage output on the first day and the length of hospital stay were significantly different depending on the treatment success or failure(P < 0.05).The abdominal radiographic improvement was correlated with whether or not the patient underwent surgery.CONCLUSION:Ileus tube can be used for adhesive small bowel obstruction.Endoscopic placement of the ileus tube is convenient and worthy to be promoted despite the potential risks.
文摘Objective To investigate the placement of a long tube into the small intestine under fluoroscopic guidance and to evaluate its decompression effect on early postoperative small bowel obstruction(EPSBO).Methods Fifty-four patients with EPSBO requiring decompression between April 2010 and July 2014 were enrolled in the study.Insertion of a long tube was guided by fluoroscopy.We first used the guide wire to pass the pylorus and then used the 10 Fr feeding tube as an exchangeable tube to put the superstiff wire into the duodenum.Finally the long tube could be passed over the guide wire through the pylorus into the intestine.The total procedure time,the radiation exposure time,and the incidence of complications were evaluated.Results The long tubes passed into the jejunum on initial insertion for all patients,so the success rate of this technique was 100%.The long tube was inserted into ileum in 18 patients.The mean total procedure time was 34.4±8.6 minutes,and the mean radiation exposure time 18.9±6.8 minutes.A total of 47 patients(87%) experienced full recovery following long-tube decompression and without the need for surgical intervention.Conclusions Using the wire-exchange technique,it is easy to place a long tube into the small bowel under fluoroscopic guidance.This decompression method is safe and effective for management of EPSBO.
基金Projects (50905144, 50875216) supported by the National Natural Science Foundation of ChinaProject (09-10) supported by the State Key Laboratory of Materials Processing and Die & Mould Technology, ChinaProject (JC201028) supported by the Northwestern Polytechnical University Foundation for Fundamental Research, China
文摘Thin-walled aluminum alloy tube numerical control （NC） bending with small bending radius is a complex process with multi-factor coupling effects and multi-die constraints. A significance-based optimization method of the parameters was proposed based on the finite element （FE） simulation, and the significance analysis of the processing parameters on the forming quality in terms of the maximum wall thinning ratio and the maximum cross section distortion degree was implemented using the fractional factorial design. The optimum value of the significant parameter, the clearance between the tube and the wiper die, was obtained, and the values of the other parameters, including the friction coefficients and the clearances between the tube and the dies, the mandrel extension length and the boost velocity were estimated. The results are applied to aluminum alloy tube NC bending d50 mm×1 mm×75 mm and d70 mm×1.5 mm×105 mm （initial tube outside diameter D0 × initial tube wall thickness t0 × bending radius R）, and qualified tubes are produced.
基金Supported by National Natural Science Fundation of China(No.81000387)
文摘AIMTo determine whether small interfering RNA (siRNA) of PGC-1α could inhibit vascular endothelial growth factor (VEGF) expression and tube formation in human retinal vascular endothelial cells (hRVECs).METHODShRVECs transfected with peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) siRNA were incubated for 24h and then placed into a normoxic (20%, O<sub>2</sub>) or hypoxic (1%, O<sub>2</sub>) environment for another 16h. PGC-1α mRNA and protein levels were detected by real-time PCR and Western blot. VEGF mRNA and protein levels were detected by real-time PCR and ELISA. Cell proliferation was evaluated by BrdU incorporation assay. Forty-eight hours after siRNA transfection, hRVECs were planted into Matrigel-coated plates and cultured under normoxic (20%, O<sub>2</sub>) or hypoxic (1%, O<sub>2</sub>) conditions for another 48h. The tube formation of hRVECs was observed under an optical microscope and quantified by counting the number of branch points and calculating the total tube length.RESULTSPGC-1α mRNA and protein levels were significantly reduced by PGC-1α siRNA, and VEGF mRNA and protein levels also decreased significantly. The percentage of BrdU-labeled cells in siPGC-1α groups were significantly decreased compared with control siRNA groups under normoxia and hypoxia in cell proliferation assay. In the tube formation assay, PGC-1α siRNA treated cells formed significantly fewer tubes.CONCLUSIONBlocking PGC-1α expression can inhibit VEGF expression in hRVECs and inhibit their ability to form tubes under both normoxic and hypoxic conditions.
文摘Purpose: To evaluate the quality of three-dimensional (3D) CT angiography images of the abdominal viscera with small focal spot, low tube voltage, and iterative model reconstruction technique (IMR). Materials and Methods: Seven patients with suspected disease of the pancreatobiliary system had undergone CT with high-quality CTA protocol in the present study. There were 5 men and 2 women, ranging in age from 52 to 80 years (mean: 64 years). Results: Depiction of abdominal small artery, small portal vein was possible in all cases. In two cases that we were able to compare, it was superior to standard CTA in small vascular depiction in CTA made clearly in high quality protocol. Conclusions: Although the use of small focal spot, low tube voltage, and IMR can produce higher-quality images of abdominal vessels than standard CTA, this improvement is not significant at elevated radiation doses.
基金Projects(59975076, 50175092) supported by the National Natural Science Foundation of China Project(50225518) by the National Science Found of China for Distinguished Young Scholars Project by the Teaching and Research Award Program for Outstanding Young Teachers in Higher Education Institutions of MOE, PRC Project(20020699002) by the Specialized Research Fund for the Doctoral Program of Higher Education of MOE, PRC Project (04H53057) by Aviation Science Foundation
文摘Currently requirements of thin-walled tube with small bending radius cause the defects such as wrinkling, overthinning and cross-section distortion more prone to occur in bending process. Based on the analysis of the forming characteristics by analytical and experimental methods, a complete 3D elastic-plastic FEM model of the process was developed using ABAQUS/Explicit code, including bending process, balls retracting and unloading process, and thus the plastic deformation characteristics with small bending radius were investigated. The main results show that: 1) The utmost deformation feature of the NC bending process is its continuous progressive deformation. 2) The occurring conditions of the defects such as wrinkling and tension instability in the process are obtained. The wrinkling is traditional on the double compressive stresses state and the tension instability is on the double tension stresses state. 3) The enhanced non-uniform deformation in thin-walled tube with small bending radius is demonstrated by comparing the stress/ strains distributions under the 1.5D and 1D bending conditions. 4) For ID small bending process, a new method-'stepped mandrel retraction' is proposed to improve the bending quality in experiment according to the FE simulation. The simulation results are verified by experiment.
基金Project(50225518) supported by the National Science Foundation of China for Distinguished Young ScholarsProject(59975076, 50175092) supported by the National Natural Science Foundation of ChinaProject(04H53057) supported by the Aviation Science Foundation of China
文摘Numerical control(NC) bending experiments with different process parameters were carried out for 5052O aluminum alloy tubes with outer diameter of 70 mm, wall thickness of 1.5 mm, and centerline bending radius of 105 mm. And the effects of process parameters on tube wall thinning and cross section distortion were investigated. Meanwhile, acceptable bending of the 5052O aluminum tubes was accomplished based on the above experiments. The results show that the effects of process parameters on bending process for large diameter thin-walled aluminum alloy tubes are similar to those for small diameter thin-walled tubes, but the forming quality of the large diameter thin-walled aluminum alloy tubes is much more sensitive to the process parameters and thus it is more difficult to form.
文摘Background: Accurate determination of the optimal insertion depth of a pediatric endotracheal tube (ETT) is quite important. The aim of this study was to create an easily available formula that can be used to determine the optimal insertion depth for a cuffed ETT even without depth marking with clear definitions of the upper and lower limits for the tip of ETT in the trachea in clinical practice. Methods: Eighty children under 12 years of age were enrolled. The depth marking of the cuffed ETT was placed at the vocal cords and both lungs were then auscultated using a stethoscope. The upper limit was radiographically defined as the position of the tip of the cuffed ETT being between the clavicles. The lower limit was defined as a distance of 5 mm above the carina. The relationship between the insertion depth and patient characteristics was analyzed to create a formula for optimal ETT insertion depth. Results: Sixty-nine ETTs were optimally placed in the trachea. There were good correlations between the optimal insertion depth of ETTs and patients characteristics (height (R = 0.92);BSA (R = 0.92);weight (R = 0.91);age (R = 0.88)). Using these patient characteristics, we created the following three formulas for calculation of the optimal insertion depth for pediatric cuffed ETTs: insertion depth (cm) = height (cm)/11 + 5.5, weight (kg)/3 + 9.5 or 11 + 3/4 × age (years). The rates of appropriate tube placement of both pediatric cuffed ETTs were 87.5% (Hi-Contour) and 85.0% (Microcuff). Conclusions: Our formula and graphs may be easy to determine the optimal insertion depth of cuffed ETT even without depth marking in clinical practice.
文摘Two-phase flow pressure drop measurements were made during the phase change heat transfer process of R22 in a small horizontal smooth tube with 2.5 mm inside diameter. Conclusions can be drawn that the quality corresponding to the pressure gradient peak value of small tubes became higher than that of large tubes. The effect of quality to pressure drop becomes weak as the mass flux increases. The experiment data were compared with the predicated values of the state-of-the-art correlations from the open literature. The comparisons between the data and the predictions indicate that most of the state-of-the-art correlations fails to predict the experimental data. Chisholm model shows a relatively better predictive ability than the other empirical correlations although it has a mean deviation of 26.7%. But the predicated values of Chisholm model are lower by 50% than the experimental data when the quality becomes larger.
文摘Background: Surveys of pediatric endotracheal tube (ETT) management previously reported that specialists in pediatric anesthesia and intensive care medicine preferred to use uncuffed ETTs for children younger than 8 to 10 years of age. The aim of this study was to reveal the most recent attitudes and clinical practices of pediatric ETT management in Japan. Methods: The attitudes and clinical practices of pediatric ETT management were investigated using the data sheets of each institution and each patient. The data sheets contained information on patient characteristics and type of hospital, surgical procedures, devices used for intubation, and ETT information including types, size, depth, intracuff pressure (ICP), interval of ICP measurement, laryngeal packing, ETT exchange, airway complications, and reintubations. Results: The response rate of this survey was 66.7%. More than half of children older than 2 years of age were intubated with cuffed ETTs;83.5% of cuffed ETTs were used with the cuffs inflated, and ICP was measured in 80.7% of cuffed ETTs. More than half of ICP measurements were only taken at the time of intubation. Post-extubation stridor was rarely observed in cuffed (0.4%) or uncuffed ETTs (1.2%). The pediatric ETT management questionnaire revealed age-based size selection, differences in pressure of air leakage between cuffed (15 - 20 cmH2O) and uncuffed ETTs (20 - 30 cmH2O) of different sizes, the depthmarking method of insertion length. Continuous measurement of ICP was not common. Conclusion: This study revealed widespread use of cuffed ETTs in children older than 2 years of age, rarely occurrence of post-extubation stridor, inflation of cuffs, and practice of ICP measurement.
文摘BACKGROUND Early postoperative inflammatory small bowel obstruction(EPISBO)is easy to be complicated after colorectal cancer surgery.Both intestinal obstruction catheter and meglumine can treat EPISBO.AIM To investigate the efficacy of an intestinal obstruction tube combined with meg-lumine diazo in treating EPISBO of colorectal cancer.METHODS Data from 60 patients with colorectal cancer and intestinal obstruction admitted to the Proctology Department of our hospital from April 2018 to May 2022 were collected and analyzed and divided into three cohorts according to different treatment regimens.Cohort A(n=20)received a transnasal intestinal obstruction catheter with panumglumine,and cohort B(n=20)received a transnasal intestinal obstruction catheter with liquid paraffin.Cohort C(n=20)received oral treatment with meglumine.The clinical efficacy,first exhaust/defecation time,length of hospital stay,gastrointestinal decompression time,relief time of abdo-minal pain,and relief time of abdominal distension were compared among the three cohorts.The levels of C-reactive protein(CRP),tumor necrosis factor-α(TNF-α),interleukin-6(IL-6),monocyte chemotactic protein-1(MCP-1),serum albumin,and transferrin were compared among the three cohorts before and after treatment.The occurrence of adverse reactions in the three cohorts was compared.RESULTS Compared with cohort C,the successful treatment rate of cohort A was signi-ficantly higher.There were statistically significant variations in the time of first exhaust/defecation,length of hospital stays,gastrointestinal decompression time,relief time of abdominal pain,and relief time of abdominal distention among the three cohorts.Compared with cohort C,cohort A’s first exhaust/defecation time,hospitalization time,gastrointestinal decompression time,abdominal pain relief time,and abdominal distension relief time was reduced(P<0.05).After treatment,serum CRP,TNF-α,IL-6,and MCP-1 expression levels increased,and serum albumin and serum transferrin levels increased in the three cohorts.The serum albumin level in cohort A was higher than in cohort C.Compared with cohort B and cohort C,the serum transferrin level in cohort A increased(P<0.05).Compared with cohort C,the total incidence of adverse reactions in cohorts A and B was significantly higher(P<0.05).The incidence of adverse reactions was similar between cohort A and cohort B.CONCLUSION Using an ileus tube combined with meglumine diatrizoate can effectively treat postoperative inflammatory ileus obstructions after surgery colorectal cancer and improve prognosis,inflammatory response,and nutritional status.
文摘The present study was conducted to evaluate minimally invasive tube cystostomy technique in goats and calves suffering from obstructive urolithiasis having intact and ruptured urinary bladder. This clinical study was carried out on 84 clinical cases （61 goats and 23 calves） based on the history, clinical signs and physical examination along with common laboratory techniques at the Chittagong Veterinary and Animal Sciences University during January 2015-December 2016. Physical parameters like heart rate, respiratory rate, rectal temperature and dehydration status of animals were noted and corrected abnormality before surgery. Some cases had slightly higher haemoglobin （Hb）, packed cell volume （PCV） and uric acid and epithelial casts in urine. The study revealed that abnormal calcium-phosphorus ratio was predisposing the animals to urolithiasis. It was found that young ruminants （3-5 months） were most commonly affected in both species. All affected animals were male in this study, in which calves were not castrated but in goats 95.08% animals were castrated. Rupture of bladder was more common in calves as compared to goats. Postoperatively all cases were administered with broad-spectrum antibiotic, anti-inflammatory agent and caliculolytic agents like ammonium chloride. Tube cystostomy with Foley’s catheter was the most satisfactory technique for the management of obstructive urolithiasis in small ruminants. Postoperative complications were recorded only in four animals and remaining 80 animals had a normal recovery from tube cystostomy. Tube cystostomy is a simple, inexpensive and very effective procedure for the treatment of urolithiasis in ruminants.
文摘The welding temperature field and deformation of parallel arrangement small-section rectangular tubes is calculated by using a non-contact model. After comparing the computed results with the experimentally measured results, it shows that there exist big errors when applying this model to the numerical simulation of small-section rectangular tube＇ s welding temperature field and deformation. Based on a simple analysis of the errors, a contact model is presented. The heat transfer and stress analysis between small-section rectangular tubes and clamping fixture are simulated by using direct constraints method, and then the laws of the temperature distribution, which coincide with experiment, are obtained. A further numerical analysis of the stress and deformation are made, it shows that a ＂T＂ shaped stress-field is formed in the vicinity of the weld. As the stress-field departs from the centroid of tubes＇, this leads to the small rectangular tubes not only have a longitudinal deflection, but also have a transverse bending and deformation.
