BACKGROUND Primary aortoduodenal fistula is a rare cause of gastrointestinal(GI)bleeding consisting of abnormal channels between the aorta and GI tract without previous vascular intervention that results in massive in...BACKGROUND Primary aortoduodenal fistula is a rare cause of gastrointestinal(GI)bleeding consisting of abnormal channels between the aorta and GI tract without previous vascular intervention that results in massive intraluminal hemorrhage.CASE SUMMARY A 67-year-old man was hospitalized for coffee ground vomiting,tarry stools,and colic abdominal pain.He was repeatedly admitted for active GI bleeding and hypovolemic shock.Intermittent and spontaneously stopped bleeders were undetectable on multiple GI endoscopy,angiography,computed tomography angiography(CTA),capsule endoscopy,and ^(99)mTc-labeled red blood cell(RBC)scans.The patient received supportive treatment and was discharged without signs of rebleeding.Thereafter,he was re-admitted for bleeder identification.Repeated CTA after a bleed revealed a small aortic aneurysm at the renal level contacting the fourth portion of the duodenum.A ^(99)mTc-labeled RBC singlephoton emission CT(SPECT)/CT scan performed during bleeding symptoms revealed active bleeding at the duodenal level.According to his clinical symptoms(intermittent massive GI bleeding with hypovolemic shock,dizziness,dark red stool,and bloody vomitus)and the abdominal CTA and ^(99)mTc-labeled RBC SPECT/CT results,we suspected a small aneurysm and an aortoduodenal fistula.Subsequent duodenal excision and duodenojejunal anastomosis were performed.A 7-mm saccular aneurysm arising from the anterior wall of the abdominal aorta near the left renal artery was identified.Percutaneous intravascular stenting of the abdominal aorta was performed and his symptoms improved.CONCLUSION Our findings suggest that ^(99)mTc-labeled RBC SPECT/CT scanning can aid the diagnosis of a rare cause of active GI bleeding.展开更多
New materials that exhibit strong second-order optical nonlinearities at a desired operational frequency are of paramount importance for nonlinear optics.Giant second-order susceptibility χ^((2)) has been obtained in...New materials that exhibit strong second-order optical nonlinearities at a desired operational frequency are of paramount importance for nonlinear optics.Giant second-order susceptibility χ^((2)) has been obtained in semiconductor quantum wells(QWs).Unfortunately,the limited confining potential in semiconductor QWs causes formidable challenges in scaling such a scheme to the visible/near-infrared(NIR)frequencies for more vital nonlinear-optic applications.Here,we introduce a metal/dielectric heterostructured platform,i.e.,TiN/Al_(2)O_(3) epitaxial multilayers,to overcome that limitation.This platform has an extremely high χ^((2)) of approximately 1500 pm/V at NIR frequencies.By combining the aforementioned heterostructure with the large electric field enhancement afforded by a nanostructured metasurface,the power efficiency of second harmonic generation(SHG)achieved 10^(−4) at an incident pulse intensity of 10 GW/cm^(2),which is an improvement of several orders of magnitude compared to that of previous demonstrations from nonlinear surfaces at similar frequencies.The proposed quantum-engineered heterostructures enable efficient wave mixing at visible/NIR frequencies into ultracompact nonlinear optical devices.展开更多
文摘BACKGROUND Primary aortoduodenal fistula is a rare cause of gastrointestinal(GI)bleeding consisting of abnormal channels between the aorta and GI tract without previous vascular intervention that results in massive intraluminal hemorrhage.CASE SUMMARY A 67-year-old man was hospitalized for coffee ground vomiting,tarry stools,and colic abdominal pain.He was repeatedly admitted for active GI bleeding and hypovolemic shock.Intermittent and spontaneously stopped bleeders were undetectable on multiple GI endoscopy,angiography,computed tomography angiography(CTA),capsule endoscopy,and ^(99)mTc-labeled red blood cell(RBC)scans.The patient received supportive treatment and was discharged without signs of rebleeding.Thereafter,he was re-admitted for bleeder identification.Repeated CTA after a bleed revealed a small aortic aneurysm at the renal level contacting the fourth portion of the duodenum.A ^(99)mTc-labeled RBC singlephoton emission CT(SPECT)/CT scan performed during bleeding symptoms revealed active bleeding at the duodenal level.According to his clinical symptoms(intermittent massive GI bleeding with hypovolemic shock,dizziness,dark red stool,and bloody vomitus)and the abdominal CTA and ^(99)mTc-labeled RBC SPECT/CT results,we suspected a small aneurysm and an aortoduodenal fistula.Subsequent duodenal excision and duodenojejunal anastomosis were performed.A 7-mm saccular aneurysm arising from the anterior wall of the abdominal aorta near the left renal artery was identified.Percutaneous intravascular stenting of the abdominal aorta was performed and his symptoms improved.CONCLUSION Our findings suggest that ^(99)mTc-labeled RBC SPECT/CT scanning can aid the diagnosis of a rare cause of active GI bleeding.
基金financially supported by the National Science Foundation,Division of Material Research(NSF-DMR-1610538)Division of Chemistry(NSFCHE-1807891)+1 种基金DARPA DSO-NLM Program(Grant No.HR00111820038)the financial support of the International Postdoctoral Exchange Fellowship Program(No.20170010).
文摘New materials that exhibit strong second-order optical nonlinearities at a desired operational frequency are of paramount importance for nonlinear optics.Giant second-order susceptibility χ^((2)) has been obtained in semiconductor quantum wells(QWs).Unfortunately,the limited confining potential in semiconductor QWs causes formidable challenges in scaling such a scheme to the visible/near-infrared(NIR)frequencies for more vital nonlinear-optic applications.Here,we introduce a metal/dielectric heterostructured platform,i.e.,TiN/Al_(2)O_(3) epitaxial multilayers,to overcome that limitation.This platform has an extremely high χ^((2)) of approximately 1500 pm/V at NIR frequencies.By combining the aforementioned heterostructure with the large electric field enhancement afforded by a nanostructured metasurface,the power efficiency of second harmonic generation(SHG)achieved 10^(−4) at an incident pulse intensity of 10 GW/cm^(2),which is an improvement of several orders of magnitude compared to that of previous demonstrations from nonlinear surfaces at similar frequencies.The proposed quantum-engineered heterostructures enable efficient wave mixing at visible/NIR frequencies into ultracompact nonlinear optical devices.
