Simulation Analysis of Medium Access Techniques

This paper presents comparison of Access Techniques used in Medium Access Control (MAC) protocol for Wireless Body Area Networks (WBANs). Comparison is performed between Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA), Pure ALOHA and Slotted ALOHA (S-ALOHA). Performance metrics used for comparison are throughput (T), delay (D) and offered load (G). The main goal for comparison is to show which technique gives highest Throughput and lowest Delay with increase in Load. Energy efficiency is major issue in WBAN that is why there is need to know which technique performs best for energy conservation and also gives minimum delay.Comment: NGWMN with 7th IEEE International Conference on Broadband and Wireless Computing, Com- munication and Applications (BWCCA 2012), Victoria, Canada, 201

Transmission Delay of Multi-hop Heterogeneous Networks for Medical Applications

Nowadays, with increase in ageing population, Health care market keeps growing. There is a need for monitoring of Health issues. Body Area Network consists of wireless sensors attached on or inside human body for monitoring vital Health related problems e.g, Electro Cardiogram (ECG), ElectroEncephalogram (EEG), ElectronyStagmography(ENG) etc. Data is recorded by sensors and is sent towards Health care center. Due to life threatening situations, timely sending of data is essential. For data to reach Health care center, there must be a proper way of sending data through reliable connection and with minimum delay. In this paper transmission delay of different paths, through which data is sent from sensor to Health care center over heterogeneous multi-hop wireless channel is analyzed. Data of medical related diseases is sent through three different paths. In all three paths, data from sensors first reaches ZigBee, which is the common link in all three paths. After ZigBee there are three available networks, through which data is sent. Wireless Local Area Network (WLAN), Worldwide Interoperability for Microwave Access (WiMAX), Universal Mobile Telecommunication System (UMTS) are connected with ZigBee. Each network (WLAN, WiMAX, UMTS) is setup according to environmental conditions, suitability of device and availability of structure for that device. Data from these networks is sent to IP-Cloud, which is further connected to Health care center. Main aim of this paper is to calculate delay of each link in each path over multihop wireless channel.Comment: BioSPAN with 7th IEEE International Conference on Broadband and Wireless Computing, Communication and Applications (BWCCA 2012), Victoria, Canada, 201

MOLECULAR CHARACTERIZATION BY USING RANDOM AMPLIFIED POLYMORPHIC DNA (RAPD) ANALYSIS OF SALMONELLA ENTERITIDIS ISOLATES RECOVERED FROM AVIAN AND HUMAN SOURCES

Random amplified polymorphic DNA (RAPD) analysis was applied for molecular characterization of five Salmonella enteritidis strains from different avian sources and human cases of infection. A total of 16 primers were used and only five primers showed good discriminatory power for all five isolates. Dendrogram showed a common lineage among all five isolates. There was a close genetic relationship among isolates of eggs and human sources, while there was less pronounced homology among isolates of broiler meat and human sources. On the basis of results we have found that an endemic strain of S. enteritidis is prevalent between the poultry derived food and humans which gives us an insight to genetic diversity of S. enteritidis from these sources

The Effect of Changes in the ASCA Calibration on the Fe-Kalpha Lines in Active Galaxies

The ASCA calibration has evolved considerably since launch and indeed, is still evolving. There have been concerns in the literature that changes in the ASCA calibration have resulted in the Fe-Kalpha lines in active galaxies (AGN) now being systematically narrower than was originally thought. If this were true, a large body of ASCA results would be impacted. In particular, it has been claimed that the broad red wing (when present) of the Fe-Kalpha line has been considerably weakened by changes in the ASCA calibration. We demonstrate explicitly that changes in the ASCA calibration over a period of about eight years have a negligible effect on the width, strength, or shape of the Fe-Kalpha lines. The reduction in both width and equivalent width is only ~8% or less. We confirm this with simulations and individual sources, as well as sample average profiles. The average profile for type 1 AGN is still very broad, with the red wing extending down to ~4 keV. The reason for the claimed, apparently large, discrepancies is that in some sources the \fekalfa line is complex, and a single-Gaussian model, being an inadequate description of the line profile, picks up different portions of the profile with different calibration. Single-Gaussian fits do not therefore model all of the line emission in some sources, in which case they do not compare old and current calibration since the models do not then describe the data.Comment: Accepted for publication in the Astrophysical Journal, Vol. 569, 10 April, 2002. 22 pages, 4 figure

Unenhanced helical CT of ureterolithiasis: incidence of secondary urinary tract findings

Objective: To determine the incidence of secondary signs of obstruction in patients with ureteral stones on unenhanced helical CT scans.MATERIAL AND Methods: Three hundred consecutive patients with suspected renal colic referred by the emergency department for an unenhanced helical CT scan were evaluated. One hundred and thirty two patients with ureteric calculi were viewed prospectively for the secondary signs of obstruction, which include hydronephrosis, hydroureter, perinephric stranding, nephromegaly, periureteral edema and difference in attenuation between acutely obstructed kidney and unobstructed kidney.Results: In the evaluated 132 patients, calculi were present in the proximal, mid and distal ureter in 12, 18 and 112 patients respectively. Four patients had a contralateral ureteric calculus while none had more than one ureteric calculus on the same site. Concurrent renal parenchymal calculi were seen in 40 patients with ureteric stones, hydronephrosis in 69, hydroureter in 93 and perinephric strandings in 66 patients. Nephromegaly was seen in 15 and periureteral edema in 42 patients. In 87% patients with acute renal obstruction, the affected kidney was less dense than the unobstructed kidney. Only 5 of 132 patients had no associated findings.CONCLUSION: Unenhanced helical CT has rapidly become the imaging technique of choice in evaluating patients with acute ureteric colic. The secondary signs of obstruction provide supportive evidence of acute obstructive process

Radiologic feeding gastrostomy placement: experience in 23 patients

Objective: To evaluate the safety, efficacy and complications of percutaneous gastrostomy catheter placementunder flouro guidance for long-term enteral feeding.MATERIALS AND Methods: Between April 1998 to May 2002, 23 patients who had percutaneous gastrostomy catheter placement were retrospectively reviewed. Clinical indications for catheter placement included patients with neurologic disease, head and neck malignancy, and pulmonary disease patients. Placement of 12 - 14 Fr gastrostomy catheter was then accomplished with the Seldinger technique. The technical success, procedural complications were recorded.Results: Twenty seven procedures, including revisions, were performed. The success rate for catheter placement was 100%. Revision was necessary in 7 (30%) instances in 7 patients. There was one (3.8%) major and 4 (14.8%) minor complications.CONCLUSION: Fluoroscopically directed percutaneous placement of gastrostomy catheters is a safe and effective procedure

The role of magnetic resonance cholangiopancreatography (MRCP) in obstructive jaundice

Objective: To evaluate the diagnostic value of MRCP in studying the sites and cause of obstructive jaundice in comparison with other imaging modalities at the Department of Radiology, Aga Khan University Hospital, from January 1999 to May 2001.Methods: Forty nine consecutive patients included 19 men and 30 women, suspected of obstructive jaundice. Patients underwent ultrasound (n = 49), CT (n = 11), ERCP (n = 25) and biliary surgery (n = 17). Final diagnosis was established by surgical exploration, endoscopic sphincterectomy, cytology and clinical follow up.Results: Of the 49 patients 17 had choledocholithiasis. Twenty five patients had malignant strictures, out of which 11 had non-specific malignant strictures, 7 had pancreatic carcinoma, 3 had Klatskin tumors, 3 had periampullary carcinoma and 1 had gallbladder carcinoma. Six patients had benign strictures and 1 patient had choledochal cyst. Overall, MRCP was sensitive (88%) and specific (96.8%) in detecting choledocholithiasis. MRCP sensitivity and specificity in detecting benign main bile duct stricture was equal to 83.3% and 97.6% respectively, and 92% and 100% for malignant stricture.CONCLUSION: Our prospective study confirms that MRCP, a noninvasive and well tolerated imaging technique is of value in the diagnosis of obstructive jaundice