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Endoscopic Assisted Microscopic Surgical Removal of Craniopharyngioma

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Open Journal of Modern Neurosurgery 2020年第4期10卷 475-482页

作者： Waleed Abbass amr mohsen Department of Neurosurgery Faculty of Medicine Cairo University Giza Egypt

Background: Craniopharyngioma is a benign tumor which represents 2% - 3% of all intracranial tumors, there are two types: childhood type which affects children between 5 and 10 years and adulthood type which affects patients 50 - 60 years old. The presenting symptoms develop over years and include visual, endocrine, hypothalamic, neurological and neurophysiological manifestations. Surgery is the treatment of choice. Postoperative radiotherapy, gamma-knife and intra tumoral injection of chemotherapeutic drugs have been used as an adjuvant therapy in some cases. Objectives: In this study, we evaluated the role of endoscopy in assisting microscopic surgical removal of craniopharyngioma. Methods: Eleven patients were operated upon in Cairo University Hospitals, Egypt. All operations were done using microscope through the subfrontal approach. At the end of surgery, the endoscope was used to detect any residual tumor in the subchiasmatic and retrochiasmatic areas and to visualize the posterior part of the tumor which couldn’t be seen by the microscope to check if it was adherent to the hypothalamus and to evaluate whether to be removed or not. Results: The study included eleven cases, four of which were childhood type and seven adult type craniopharyngiomas. Total removal was achieved in six cases (five cases of adulthood type). Oumaya reservoir was inserted in five cases;ventriculoperitoneal shunt was needed in five cases. All cases suffered from temporary diabetes insipidus postoperatively, while only two cases developed permanent diabetes insipidus. Three cases presented preoperatively with pituitary hypofunction and two cases developed postoperative pituitary hypofunction, which necessitated hormone replacement therapy. Conclusion: Craniopharyngioma is one of the most difficult and challenging tumors for neurosurgeons due to its relation to optic nerve, hypothalamus and vascular syste

关键词： Craniopharyngiomas Endoscopy Microscopy Surgery

Functional Outcomes of Decompressive Hemicraniectomy for Treatment of Malignant Infarctions of the Middle Cerebral Artery

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Open Journal of Modern Neurosurgery 2020年第3期10卷 307-317页

作者： amr mohsen Waleed Abbass Faculty of Medicine Cairo University Cairo Egypt

Introduction: Malignant middle cerebral artery (MCA) infarction is a devastating entity that is associated with up to 80% mortality. Decompressive Hemicraniectomy has been utilized to treat brain swelling and mass effect secondary to these infarctions in an attempt to improve functional outcome. Aim: To evaluate the functional outcome of decompressive hemicraniectomy in management of malignant MCA infarctions. Methods: The study included 30 patients with malignant MCA infarctions operated upon by decompressive hemicraniectomy and duroplasty with pericranium or fascia lata graft in the period from June 2016 to January 2019. Pre-operative neurological condition, associated morbidity, location and extent of the infarction were assessed. Surgery was performed within 48 hours of the onset of stroke or 12 hours within deterioration of conscious level. Pre-operative CT scan as well as sequential post-operative CT was done. Functional outcome was assessed by the modified Rankin Scale (mRS) at the time of discharge and 3 months following surgery. Results: The study included 18 males and 12 females with a mean age of 54.7 years. The pre-operative GCS was Conclusion: Decompressive hemicraniectomy improves functional outcome in cases of malignant MCA infarction. Pre-operative GCS, age, volume of infarction, degree of midline shift, timing of surgery and associated morbidity are the most important factors affecting the outcome.

关键词： Decompressive Hemicraniectomy Malignant MCA Infarction Functional Outcome Modified Rankin Scale

α粒子感生电荷收集测量和一种新型P阱保护势垒在VLSI存储器中应用的有效性

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微电子学 1986年第2期 110-116页

作者： SAI-WAI FU,amr M.mohsen,赖宗声英特尔公司英特尔公司

本文给出了存贮器阵列中α粒子感生载流子的模拟电荷收集测量的实验结果。报道了用高强度的箔和可变角度准直α粒子源对各种不同反射结构的存贮器阵列的电荷收集测量方法。用一种新型P阱势垒,电荷收集可减低两倍、软误差率（SER）可降... 详细信息

本文给出了存贮器阵列中α粒子感生载流子的模拟电荷收集测量的实验结果。报道了用高强度的箔和可变角度准直α粒子源对各种不同反射结构的存贮器阵列的电荷收集测量方法。用一种新型P阱势垒,电荷收集可减低两倍、软误差率（SER）可降低大约两个数量级。本文还提出了P阱掺杂浓度、深度、偏置电压和它与P+衬底上P-外延层的相互作用的实验分析结果。在154密耳中的64k DRAM电路有特别低的SER,即在1μs周期时间内SER低于0.001％千小时,这就证明了采用P阱势垒结构的有效性。

关键词：电荷收集阵列势垒存贮器存储器 VLSI α粒子阿尔法粒子带电粒子有效性

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C-H-MOS已进入动态RAM的制造领域

微电子学 1985年第2期 58-63页

作者： Ken Yu Ron Chwang amr mohsen 王万业

高性能的 CMOS集成电路即将取代非常复杂的 n-NOS随机存取存贮器

关键词：随机存取行译码器芯片尺寸 C-H-MOS RAM 按比例缩小列地址工艺步骤掩模沟道长度

Validation of a Novel Method for Cardiac Output Estimation by CT Coronary Angiography

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Advances in Computed Tomography 2012年第2期1卷 11-16页

作者： Hetal H. Mehta Brian G. Choi Reza Sanai Raman S. Dusaj amr mohsen Chunlei Liang Jannet F. Lewis Robert K. Zeman Department of Mechanical and Aerospace Engineering The George Washington University Washington DC USA Department of Medicine The George Washington University Washington DC USA Department of Radiology The George Washington University Washington DC USA

Background: Cardiac output can be estimated during retrospectively gated CT coronary angiography by anatomically determining left ventricular volumes;prospective triggering to minimize radiation precludes this methodology. We propose an alternative method for cardiac output estimation based on preclinical models suggesting that cardiac output may be inversely related to contrast washout from the aortic root during timing bolus scanning, as measured by peak aortic root contrast attenuation. Methods: 34 patients had CT coronary angiography timing bolus performed with 20 ml iodixanol at 5.5 ml/s followed by 20 ml normal saline at 5.5 ml/s through an 18-Ga antecubital catheter. Peak aortic root contrast attenuation was correlated to cardiac output calculated by echocardiography using heart rate stroke volume from biplane Simpson’s ***: Mean age was 58 ± 13 years;body surface area, 2.0 ± 0.5 m2. 53% were women. Stroke volume, cardiac output and cardiac index were 67 ± 19 ml, 4.5 ± 1.6 L/min, and 2.2 ± 0.7 L/min/m2, respectively. Peak aortic root contrast attenuation was 207 ± 46 HU and correlated to cardiac output and cardiac index with r = –0.64, p Conclusion: This novel method for cardiac output estimation by CTCA appears feasible. The CT physiologic parameters using the timing test-bolus data moderately correlated with echocardiographic assessment of cardiac output. The calculation of cardiac output adds important hemodynamic data to anatomic information provided by CTCA, and further development of this method may preserve assessment of left ventricular performance in prospective triggering.

关键词： Cardiac Output Coronary CT Angiography Hemodynamics Prospective Triggering Validation

Long-term results of Ahmed glaucoma valve implantation in Egyptian population

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International Journal of Ophthalmology(English edition) 2018年第3期11卷 416-421页

作者： Eman Elhefney Tharwat Mokbel Waleed Abou Samra Hanem Kishk Tarek mohsen amr El-Kannishy Department of Ophthalmology Faculty of Medicine Mansoura University

AIM： To evaluate the long-term results and complications of Ahmed glaucoma valve （AGV） implantation in a cohort of Egyptian patients. METHODS： A retrospective study of 124 eyes of 99 patients with refractory glaucoma who underwent AGV implantation and had a minimum follow-up of 5y was performed. All patients underwent complete ophthalmic examination and intraocular pressure （lOP） measurement before surgery and at ld, weekly for the 1st month, 3, 6mo, and ly after surgery and yearly afterward for 5y. lOP was measured by Goldmann applanation tonometry and/or Tono-Pen. Complications and the number of anti-glaucoma medications needed were recorded. Success was defined as lOP less than 21 mm Hg with or without anti-glaucoma medication and without additional glaucoma surgery. RESULTS： Mean age was 23.1±19.9y. All eyes had at least one prior glaucoma surgery, lOP was reduced from a mean of 37.2±6.8 to 19.2±5.2 mm Hg after 5y follow-up with a reduced number of medications from 2.64±0.59 to 1.81±0.4. Complete and qualified success rates were 31.5% and 46.0% respectively at the end of follow-up. The most common complications were encapsulated cyst formation in 51 eyes （41.1%）, complicated cataract in 9 eyes （7.25%）, recessed tube in 8 eyes （6.45%）, tube exposure in 6 eyes （4.8%） and corneal touch in 6 eyes （4.8%）. Other complications included extruded AGV, endophthalmitis and persistent hypotony. Each of them was recorded in only 2 eyes （1.6%）. ~ CONCLUSION： Although refractory glaucoma is a difficult problem to manage, AGV is effective and relatively safe procedure in treating refractory glaucoma in Egyptian patients with long-term follow-up. Encapsulated cyst formation was the most common complication, which limits successful lOP control after AGV implantation. However, effective complications management can improve the rate of success.

关键词： intraocular pressure Ahmed glaucoma valve refractory glaucoma long-term follow-up of glaucoma Ahmedvalve complications

Optimum allocation of FACTS devices in Fars Regional Electric Network using genetic algorithm based goal attainment

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第4期10卷 478-487页

作者： mohsen GITIZADEH mohsen KALANTAR Center of Excellence for Power System Automation and Operation Department of Electrical Engineering Iran University of Science and TechnologyTehran 16844 Iran

This paper presents a novel approach to find optimum locations and capacity of flexible alternating current transmission system (FACTS) devices in a power system using a multi-objective optimization function. Thyristor controlled series compensators (TCSCs) and static var compensators (SVCs) are the utilized FACTS devices. Our objectives are active power loss reduction, newly introduced FACTS devices cost reduction, voltage deviation reduction, and increase on the robustness of the security margin against voltage collapse. The operational and controlling constraints, as well as load constraints, were considered in the optimum allocation. A goal attainment method based on the genetic algorithm (GA) was used to approach the global optimum. The estimated annual load profile was utilized in a sequential quadratic programming (SQP) optimization sub-problem to the optimum siting and sizing of FACTS devices. Fars Regional Electric Network was selected as a practical system to validate the performance and effectiveness of the proposed method. The entire investment of the FACTS devices was paid off and an additional 2.4% savings was made. The cost reduction of peak point power generation implies that power plant expansion can be postponed.

关键词： Flexible alternating current transmission system (FACTS) devices allocation Multi-objective optimization Geneticalgorithm (GA) Goal attainment

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Effects of porous material on transient natural convection heat transfer of nano-fluids inside a triangular chamber

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Chinese Journal of Chemical Engineering 2020年第5期28卷 1203-1213页

作者： mohsen Izadi Mechanical Engineering Department Faculty of EngineeringLorestan UniversityKhorramabadIran

This study numerically investigates the impact of porous materials,nano-particle types,and their concentrations on transient natural convection heat transfer of nano-fluid inside a porous chamber with a triangular *** governing equations of the two-phase mixture model are separated on the computational domain and solved using the Finite Volume Method,taking into account the Darcy–Brinkman model for porous *** was observed that convection heat transfer inside the triangular chamber consists of three stages named initial,transient,and *** features of each step are provided in *** results suggested that the use of a hybrid nano-fluid(water/aluminum oxide-cooper)inside a porous glass material and an increase in volume fraction of nano-particles have adverse effects on heat transfer *** contrast,as the nano-particle volume fraction of the single nano-fluid(water/aluminum oxide)inside the chamber increased,convection heat transfer rate *** the same time,it was observed that the use of both nano-fluids(single and hybrid)in the porous environment of the aluminum foam could improve convection.

关键词： Transient natural convection Mixture model Darcy-Brinlanan model Rayleigh-Benard instability Triangular chamber

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Orbital electronic heat capacity of hydrogenated monolayer and bilayer graphene

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Chinese Physics B 2017年第2期26卷 375-381页

作者： mohsen Yarmohammadi Young Researchers and Elite Club Kermanshah Branch Islamic Azad University Kermanshah Ira

The tight-binding Harrison model and Green＇s function approach have been utilized in order to investigate the contribution of hybridized orbitals in the electronic density of states（DOS） and electronic heat capacity（EHC） for four hydrogenated structures, including monolayer chair-like, table-like, bilayer AA- and finally AB-stacked graphene. After hydrogenation, monolayer graphene and bilayer graphene are behave as semiconducting systems owning a wide direct band gap and this means that all orbitals have several states around the Fermi level. The energy gap in DOS and Schottky anomaly in EHC curves of these structures are compared together illustrating the maximum and minimum band gaps are appear for monolayer chair-like and bilayer AA-stacked graphane, respectively. In spite of these, our findings show that the maximum and minimum values of Schottky anomaly appear for hydrogenated bilayer AA-stacked and monolayer table-like configurations, respectively.

关键词： hydrogenated monolayer and bilayer graphene Harrison model electronic heat capacity density of states Green's function

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