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Low Complexity Precoded Greedy Power allocation algorithms for OFDM Communication Systems

Journal of Signal and Information Processing 2012年第2期3卷 185-191页

作者： Najib A. Odhah Moawad I. Dessouky waleed al-hanafy Fathi E. Abd El-Samie Department of Electronics and Electrical Communications Faculty of Electronic Engineering Menoufia University Menouf Egypt

In this paper, an enhanced greedy bit and power allocation algorithms for orthogonal frequency division multiplexing (OFDM) communication systems are introduced. These algorithms combine low complexity greedy power allocation algorithms with a simplified maximum ratio combining (MRC) precoding technique at the transmitter for maximizing the average data throughput of OFDM communication systems. Results of computer simulations show that precoding is an effective technique for improving the throughput performance of the proposed bit and power allocation algorithms.

关键词： OFDM Uniform Power allocation Greedy algorithm Throughput Enhancement MRC Precoding

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Low Complexity Precoded Greedy Power allocation algorithms for OFDM Communication Systems

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Journal of Signal and Information Processing（信号与信息处理） 2012年第2期

作者： Najib A. Odhah Moawad I. Dessouky waleed al-hanafy Fathi E. Abd El-Samie

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Outcomes of pancreaticoduodenectomy in elderly patients

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Hepatobiliary & Pancreatic Diseases International 2016年第4期15卷 419-427页

作者： Ayman El Nakeeb Ehab Atef Ehab El hanafy ali Salem waleed Askar Helmy Ezzat Ahmed Shehta Mohamed Abdel Wahab Gastroenterology Surgical Center Mansoura University

BACKGROUND： although the mortality and morbidity of pancreaticoduodenectomy（PD） have improved significantly over the past years, the concerns for elderly patients undergoing PD are still present. Furthermore, the frequency of PD is increasing because of the increasing proportion of elderly patients and the increasing incidence of periampullary tumors. This study aimed to analyze the outcomes of PD in elderly ***： We studied all patients who had undergone PD in our center between January 1995 and February 2015. The patients were divided into three groups based on age： group I（patients aged 〈60 years）, group II（those aged 60 to 69 years） and group III（those aged ≥70 years）. The primary outcome was the rate of total postoperative complications. Secondary endpoint included total operative time, hospital mortality, length of postoperative hospital stay, delayed gastric emptying, re-exploration, and survival ***： A total of 828 patients who had undergone PD for resection of periampullary tumor were included in this study. There were 579（69.9%） patients in group I, 201（24.3%） in group II, and 48（5.8%） in group III. The overall incidence of complications was higher in elderly patients（25.9% in group I, 36.8% in group II, and 37.5% in group III; P=0.006）. There were more patients complicated with delayed gastric emptying in group II compared with the other two groups. There was no significant difference in the incidence of postoperative pancreatic fistula, biliary leakage, pancreatitis, pulmonary complications and hospital ***： PD can be performed safely in selected elderly patients. Advanced age alone should not be a contraindication for PD. The outcome of elderly patients who have undergone PD is similar to that of younger patients, and the increased rate of complications is due to the presence of associated comorbidities.

关键词： pancreaticoduodenectomy elderly pancreatic fistula delayed gastric emptying

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Trends and outcomes of pancreaticoduodenectomy for periampullary tumors: A 25-year single-center study of 1000 consecutive cases

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World Journal of Gastroenterology 2017年第38期23卷 7025-7036页

作者： ayman el nakeeb waleed askar ehab atef ehab el hanafy ahmad m sultan tarek salah ahmed shehta mohamed el sorogy emad hamdy mohamed el hemly ahmed a el-geidi tharwat kandil mohamed el shobari talaat abd allah amgad fouad mostafa abu zeid ahmed abu el eneen nabil gad el-hak gamal el ebidy omar fathy ahmed sultan mohamed abdel wahab gastroenterology surgical center mansoura university

AIM To evaluate the evolution, trends in surgical approaches a n d r e c o n s t r u c t i o n t e c h n i q u e s, a n d i m p o r t a n t lessons learned from performing 1000 consecutive pancreaticoduodenectomies(PDs) for periampullary *** This is a retrospective review of the data of all patients who underwent PD for periampullary tumor during the period from January 1993 to April 2017. The data were categorized into three periods, including early period(1993-2002), middle period(2003-2012), and late period(2013-2017).RESULTS The frequency showed PD was increasingly performed after the year 2000. With time, elderly, cirrhotic and obese patients, as well as patients with uncinate process carcinoma and borderline tumor were increasingly selected for PD. The median operative time and postoperative hospital stay decreased significantly over the periods. Hospital mortality declined significantly, from 6.6% to 3.1%. Postoperative complications significantly decreased, from 40% to 27.9%. There was significant decrease in postoperative pancreatic fistula in the second 10 years, from 15% to 12.7%. There was a significant improvement in median survival and overall survival among the *** Surgical results of PD significantly improved, with mortality rate nearly reaching 3%. Pancreatic reconstruction following PD is still debatable. The survival rate was also improved but the rate of recurrence is still high, at 36.9%.

关键词： Pancreaticoduodenectomy Pancreaticogastrostomy Pancreaticojejunostomy Postoperative pancreatic fistula Periampullary tumor

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Predictors of long term survival after hepatic resection for hilar cholangiocarcinoma:A retrospective study of 5-year survivors

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World Journal of Gastrointestinal Surgery 2016年第6期8卷 436-443页

作者： Mohamed Abd El Wahab Ayman El Nakeeb Ehab El hanafy Ahmad M Sultan Ahmed Elghawalby waleed Askr Mahmoud ali Mohamed Abd El Gawad Tarek Salah Gastroenterology Surgical Center Mansoura University

AIM:To determine predictors of long term survival after resection of hilar cholangiocarcinoma(HC) by comparing patients surviving > 5 years with those who survived 5 ***:There were 34(14%) long term survivors(5 year ... 详细信息

AIM:To determine predictors of long term survival after resection of hilar cholangiocarcinoma(HC) by comparing patients surviving > 5 years with those who survived ally proven HC who underwent surgical resection at the Gastroenterology Surgical Center,Mansoura University,Egypt between January 2002 and April *** data of the patients were collected from the medical *** were divided into two groups according to their survival:patients surviving less than 5 years and those who survived > 5 ***:There were 34(14%) long term survivors(5 year survivors) among the 243 *** survivors were younger at diagnosis than those surviving less than 5 years(mean age,50.47 ± 4.45 vs 54.59 ± 4.98,p = 0.001).Gender,clinical presentation,preoperative drainage,preoperative serum bilirubin,albumin and serum glutamic-pyruvic transaminase were similar between the two *** level of CA 19-9 was significantly higher in patients surviving alysis demonstrated nine variables to be significantly associated with survival > 5 year,includingyoung age(p = 0.001),serum CA19-9(p = 0.0001),non-cirrhotic liver(p = 0.02),major hepatic resection(p = 0.001),caudate lobe resection(p = 0.006),well differentiated tumour(p = 0.03),lymph node status(0.008),R0 resection margin(p = 0.0001) and early postoperative liver cell failure(p = 0.02).CONCLUSION:Liver status,resection of caudate lobe,lymph node status,R0 resection and CA19-9 were demonstrated to be independent risk factors for long term survival.

关键词： Hilar cholangiocarcinoma hepatic resection caudate lobe resection CA19-9 liver cell failure

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