The paper presents an improved equivalent circuit parameters extraction method for the dumbbell-shaped defected ground structure (DGS). The new extraction parameters equations are obtained in closed-form expressions, ...The paper presents an improved equivalent circuit parameters extraction method for the dumbbell-shaped defected ground structure (DGS). The new extraction parameters equations are obtained in closed-form expressions, which contain S11 and S21. The DGS unit with center frequency of 5 GHz is designed and fabricated on a TLX substrate with thickness of 1 mm and dielectric constant of 2.55. The circuit simulated results are in good agreement with the measured results. This parameters extraction method can be widely used for the design and analysis of DGS .展开更多
AIM: To review imaging characteristics and surgical outcomes of orbital neurilemmoma. METHODS: Retrospective review of 21 patients with orbital neurilemmoma managed at the Zhongshan Ophthalmic Center of Sun Yat-sen Un...AIM: To review imaging characteristics and surgical outcomes of orbital neurilemmoma. METHODS: Retrospective review of 21 patients with orbital neurilemmoma managed at the Zhongshan Ophthalmic Center of Sun Yat-sen University from June 2005 to December 2016. All patients underwent surgical excision following preoperative imaging including ultrasonography, computed tomography(CT) and magnetic resonance imaging(MRI).RESULTS: Among these patients, 11 were male and 10 were female, with age ranging from 12 to 75y(average, 40.3 y). Ultrasound of the orbit showed a roundish well-demarcated orbital mass with low or middle internal reflectivity in each case. Dark inner liquid fields were detected in 28.6% of these cases. Doppler ultrasound demonstrated blood flow signals in these masses. CT showed that the tumors were either homogeneous or heterogeneous. MRI of T1 WI revealed isointense or hypointense tumors, while the T2 WI indicated heterogeneous hyperintense lesions. Gd contrast MRI demonstrated heterogenous or homogeneous enhancement initiating from the wide area of the lesion. Six patients underwent lateral orbitotomy and 15 anterior orbitotomy. All tumors were completely removed. After a mean followup of 1.8 y, 3 patients experienced reduced vision while the remaining 10 patients showed improved vision after surgery. One patient experienced a mild limitation of upward motility. No recurrence occurred. CONCLUSION: Orbital neurilemmoma is a relatively rare, benign orbital tumor. Effective diagnosis requires a combination of ultrasonography, CT and/or MRI. These imaging techniques are also vital to differentiate neurilemmomas from other orbital masses like that of cavernous hemangiomas and meningiomas.Successful treatment requires complete resection of the neurilemmomas as performed either by lateral or anterior orbitotomy. Recurrence is rare after complete removal.展开更多
BACKGROUND Tracheal tumors are relatively rare in adults and uncommon in children.Tracheal neurilemmoma is a rare condition in adults that usually affects middle-aged people,but it can also occur in children.Because t...BACKGROUND Tracheal tumors are relatively rare in adults and uncommon in children.Tracheal neurilemmoma is a rare condition in adults that usually affects middle-aged people,but it can also occur in children.Because the clinical presentation is nonspecific and insidious,diagnosis is often delayed.The most common symptoms in these patients are stridor or wheezing(especially positional)and cough.A few patients are misdiagnosed and mistakenly treated for asthma.CASE SUMMARY A 10-year-old girl was admitted to our unit with a 2-mo history of recurrent cough,dyspnea,and tachypnea.Her condition was more severe after exercise.Her symptoms progressed despite treatment with inhaled fluticasone/salmeterol.Flexible electronic laryngoscopy showed a red,smooth,and round mushroomshaped mass in the trachea,about 1 cm below the vocal cords.The surface of the mass was covered with several small and discontinuous blood vessels.About 90%of the tracheal lumen was occupied by the mass.A multidisciplinary operation was performed.The surgically resected mass was diagnosed as benign neurilemmoma by immunohistochemical analysis.CONCLUSION Intratracheal neurilemmoma is fairly rare in children.The main symptoms include coughing,wheezing,and dyspnea.The tumor’s size,location,and degree of intratracheal and extratracheal invasion can be measured by chest computed tomography.The main treatment strategies used for tracheal neurilemmoma are surgical resection and endoscopic excision.Long-term follow-up is warranted for the evaluation of outcomes and complications.展开更多
Objective To explore surgical techniques and curative effects of microsurgical treatment for neuriemmoma in upper cervical spinal canal. Methods Form Jan. 2004 to Nov. 2007. 59 cases of schwannoma was resected through...Objective To explore surgical techniques and curative effects of microsurgical treatment for neuriemmoma in upper cervical spinal canal. Methods Form Jan. 2004 to Nov. 2007. 59 cases of schwannoma was resected through microoperation, the operation was conducted through a posteromedial approach,using German Laika microscope resection展开更多
文摘The title compound 5 was synthesized in 45% yield by the reaction of compound 3 with a, a-bis (bromomethyl)-2, 2-bipyridine in CH3CN at 70℃ for 24 h.
文摘The paper presents an improved equivalent circuit parameters extraction method for the dumbbell-shaped defected ground structure (DGS). The new extraction parameters equations are obtained in closed-form expressions, which contain S11 and S21. The DGS unit with center frequency of 5 GHz is designed and fabricated on a TLX substrate with thickness of 1 mm and dielectric constant of 2.55. The circuit simulated results are in good agreement with the measured results. This parameters extraction method can be widely used for the design and analysis of DGS .
基金Supported by the National Natural Science Foundation of China(No.81670885)the Science and Technology Program of Guangdong Province,China(No.2013B020400003)Science and Technology Program of Guangzhou,China(No.15570001)
文摘AIM: To review imaging characteristics and surgical outcomes of orbital neurilemmoma. METHODS: Retrospective review of 21 patients with orbital neurilemmoma managed at the Zhongshan Ophthalmic Center of Sun Yat-sen University from June 2005 to December 2016. All patients underwent surgical excision following preoperative imaging including ultrasonography, computed tomography(CT) and magnetic resonance imaging(MRI).RESULTS: Among these patients, 11 were male and 10 were female, with age ranging from 12 to 75y(average, 40.3 y). Ultrasound of the orbit showed a roundish well-demarcated orbital mass with low or middle internal reflectivity in each case. Dark inner liquid fields were detected in 28.6% of these cases. Doppler ultrasound demonstrated blood flow signals in these masses. CT showed that the tumors were either homogeneous or heterogeneous. MRI of T1 WI revealed isointense or hypointense tumors, while the T2 WI indicated heterogeneous hyperintense lesions. Gd contrast MRI demonstrated heterogenous or homogeneous enhancement initiating from the wide area of the lesion. Six patients underwent lateral orbitotomy and 15 anterior orbitotomy. All tumors were completely removed. After a mean followup of 1.8 y, 3 patients experienced reduced vision while the remaining 10 patients showed improved vision after surgery. One patient experienced a mild limitation of upward motility. No recurrence occurred. CONCLUSION: Orbital neurilemmoma is a relatively rare, benign orbital tumor. Effective diagnosis requires a combination of ultrasonography, CT and/or MRI. These imaging techniques are also vital to differentiate neurilemmomas from other orbital masses like that of cavernous hemangiomas and meningiomas.Successful treatment requires complete resection of the neurilemmomas as performed either by lateral or anterior orbitotomy. Recurrence is rare after complete removal.
文摘BACKGROUND Tracheal tumors are relatively rare in adults and uncommon in children.Tracheal neurilemmoma is a rare condition in adults that usually affects middle-aged people,but it can also occur in children.Because the clinical presentation is nonspecific and insidious,diagnosis is often delayed.The most common symptoms in these patients are stridor or wheezing(especially positional)and cough.A few patients are misdiagnosed and mistakenly treated for asthma.CASE SUMMARY A 10-year-old girl was admitted to our unit with a 2-mo history of recurrent cough,dyspnea,and tachypnea.Her condition was more severe after exercise.Her symptoms progressed despite treatment with inhaled fluticasone/salmeterol.Flexible electronic laryngoscopy showed a red,smooth,and round mushroomshaped mass in the trachea,about 1 cm below the vocal cords.The surface of the mass was covered with several small and discontinuous blood vessels.About 90%of the tracheal lumen was occupied by the mass.A multidisciplinary operation was performed.The surgically resected mass was diagnosed as benign neurilemmoma by immunohistochemical analysis.CONCLUSION Intratracheal neurilemmoma is fairly rare in children.The main symptoms include coughing,wheezing,and dyspnea.The tumor’s size,location,and degree of intratracheal and extratracheal invasion can be measured by chest computed tomography.The main treatment strategies used for tracheal neurilemmoma are surgical resection and endoscopic excision.Long-term follow-up is warranted for the evaluation of outcomes and complications.
文摘Objective To explore surgical techniques and curative effects of microsurgical treatment for neuriemmoma in upper cervical spinal canal. Methods Form Jan. 2004 to Nov. 2007. 59 cases of schwannoma was resected through microoperation, the operation was conducted through a posteromedial approach,using German Laika microscope resection
