BACKGROUND Juvenile polyps(JPs)are non-neoplastic polyps.In adults,JPs present with hematochezia in only approximately half the patients and are often found incidentally during endoscopic screening.JPs have no mucosal...BACKGROUND Juvenile polyps(JPs)are non-neoplastic polyps.In adults,JPs present with hematochezia in only approximately half the patients and are often found incidentally during endoscopic screening.JPs have no mucosal fascia at the tip,and spontaneous shedding and massive gastrointestinal hemorrhage may occur.Thus,the JP bleeding detected in this case by extravascular contrast leakage on computed tomography scans and treated with endoscopic clipping is rare.CASE SUMMARY A previously healthy 31-year-old male patient presented with a 2-day history of bloody stools.Upon hospital arrival,rectal examination revealed fresh blood,and abdominal computed tomography scans showed extravascular contrast leakage from the lower rectum’s left-side wall.His blood pressure was slightly low at 104/62 mmHg.However,his pulse rate(69 bpm)and oxygen level(99%on room air)were within normal limits.Emergency endoscopy revealed a pedunculated lesion in the rectum covered by a non-neoplastic mucosal epithelium.No neoplastic lesions were observed at the tip of the polyp;however,pulsatile bleeding was detected at the distal end.We performed endoscopic hemostasis by clipping the stem and then performed a polypectomy above the stem to examine the lesion tissue.Histopathological evaluation revealed a cystically dilated gland without neoplastic lesions.A subsequent total colonoscopy revealed two JPs with characteristic edematous,smooth,and reddish surfaces close to the hemorrhagic lesion.Subsequent histopathological evaluation indicated findings characteristic of JP,such as severe inflammatory cell infiltration of the stroma and cystic dilatation of the glandular ducts.CONCLUSION There are no reports of adult JPs presenting with contrast extravasation where endoscopic hemostasis was successful,as in this case.展开更多
The effect of electro-pulsing treatment(EPT)with different peak current densities(Jm)on tensile properties of selective laser melting(SLM)-produced TC4 alloy was investigated for significant improvement in the tensile...The effect of electro-pulsing treatment(EPT)with different peak current densities(Jm)on tensile properties of selective laser melting(SLM)-produced TC4 alloy was investigated for significant improvement in the tensile properties of the alloy.When Jm is 30 A/mm2,the elongation is improved distinctly by 19.72%while the ultimate tensile strength remains nearly constant.The improved ductility is evidenced by deeper dimples on the fracture surface and cracks from the shear lip zone.Additionally,the improvement is reflected by widely distributed voids and prominent slip bands in the longitudinal section of the fracture.The fracture behavior is attributed to the increased high-angle grain boundaries fraction and the reduced dislocation density induced by the appropriate EPT.This microstructure leads to a decrease in texture intensity of the basal plane and an enhancement in crystalline slip capacity of the plane,consequently,the improved plastic deformation capacity of the alloy.展开更多
文摘BACKGROUND Juvenile polyps(JPs)are non-neoplastic polyps.In adults,JPs present with hematochezia in only approximately half the patients and are often found incidentally during endoscopic screening.JPs have no mucosal fascia at the tip,and spontaneous shedding and massive gastrointestinal hemorrhage may occur.Thus,the JP bleeding detected in this case by extravascular contrast leakage on computed tomography scans and treated with endoscopic clipping is rare.CASE SUMMARY A previously healthy 31-year-old male patient presented with a 2-day history of bloody stools.Upon hospital arrival,rectal examination revealed fresh blood,and abdominal computed tomography scans showed extravascular contrast leakage from the lower rectum’s left-side wall.His blood pressure was slightly low at 104/62 mmHg.However,his pulse rate(69 bpm)and oxygen level(99%on room air)were within normal limits.Emergency endoscopy revealed a pedunculated lesion in the rectum covered by a non-neoplastic mucosal epithelium.No neoplastic lesions were observed at the tip of the polyp;however,pulsatile bleeding was detected at the distal end.We performed endoscopic hemostasis by clipping the stem and then performed a polypectomy above the stem to examine the lesion tissue.Histopathological evaluation revealed a cystically dilated gland without neoplastic lesions.A subsequent total colonoscopy revealed two JPs with characteristic edematous,smooth,and reddish surfaces close to the hemorrhagic lesion.Subsequent histopathological evaluation indicated findings characteristic of JP,such as severe inflammatory cell infiltration of the stroma and cystic dilatation of the glandular ducts.CONCLUSION There are no reports of adult JPs presenting with contrast extravasation where endoscopic hemostasis was successful,as in this case.
基金financial support from the National Natural Science Foundation of China(No.52205490)the Natural Science Foundation of Sichuan Province,China(No.2022NSFSC0336)。
文摘The effect of electro-pulsing treatment(EPT)with different peak current densities(Jm)on tensile properties of selective laser melting(SLM)-produced TC4 alloy was investigated for significant improvement in the tensile properties of the alloy.When Jm is 30 A/mm2,the elongation is improved distinctly by 19.72%while the ultimate tensile strength remains nearly constant.The improved ductility is evidenced by deeper dimples on the fracture surface and cracks from the shear lip zone.Additionally,the improvement is reflected by widely distributed voids and prominent slip bands in the longitudinal section of the fracture.The fracture behavior is attributed to the increased high-angle grain boundaries fraction and the reduced dislocation density induced by the appropriate EPT.This microstructure leads to a decrease in texture intensity of the basal plane and an enhancement in crystalline slip capacity of the plane,consequently,the improved plastic deformation capacity of the alloy.
