Experiences With Surgical Treatment of Chronic Lower Limb Ulcers at a Tertiary Hospital in Northwestern Tanzania: A Prospective Review of 300 Cases.

Chronic lower limb ulcers constitute a major public health problem of great important all over the world and contribute significantly to high morbidity and long-term disabilities. There is paucity of information regarding chronic lower limb ulcers in our setting; therefore it was necessary to conduct this study to establish the patterns and outcome of chronic lower limb ulcers and to identify predictors of outcome in our local setting. This was a descriptive prospective study of patients with chronic lower limb ulcers conducted at Bugando Medical Centre between November 2010 and April 2012. Ethical approval to conduct the study was sought from relevant authorities. Statistical data analysis was done using SPSS version 17.0 and STATA version 11.0. A total of 300 patients were studied. Their ages ranged from 3 months to 85 years (median 32 years). The male to female ratio was 2:1. The median duration of illness was 44 days. Traumatic ulcer was the most frequent type of ulcer accounting for 60.3% of patients. The median duration of illness was 44 days. The leg was commonly affected in 33.7% of cases and the right side (48.7%) was frequently involved. Out of 300 patients, 212 (70.7%) had positive aerobic bacterial growth within 48 hours of incubation. Pseudomonas aeruginosa (25.5%) was the most frequent gram negative bacteria isolated, whereas gram positive bacteria commonly isolated was Staphylococcus aureus (13.7%). Twenty (6.7%) patients were HIV positive with a median CD4+ count of 350 cells/μl. Mycological investigation was not performed. Bony involvement was radiologically reported in 83.0% of cases. Histopathological examination performed in 56 patients revealed malignancy in 20 (35.7%) patients, of which malignant melanoma (45.0%) was the most common histopathological type. The vast majority of patients, 270 (90.0%) were treated surgically, and surgical debridement was the most common surgical procedure performed in 24.1% of cases. Limb amputation rate was 8.7%. Postoperative complication rate was 58.3% of which surgical site infection (77.5%) was the most common post-operative complications. The median length of hospital stay was 23 days. Mortality rate was 4.3%. Out of the two hundred and eighty-seven (95.7%) survivors, 253 (91.6%) were treated successfully and discharged well (healed). After discharge, only 35.5% of cases were available for follow up at the end of study period. Chronic lower limb ulcers remain a major public health problem in this part of Tanzania. The majority of patients in our environment present late when the disease is already in advanced stages. Early recognition and aggressive treatment of the acute phase of chronic lower limb ulcers at the peripheral hospitals and close follow-up are urgently needed to improve outcomes of these patients in our environment

Experimental investigation of retrofitting techniques for steel bridge girders subject to fatigue failure

Fatigue failure is major concern for infrastructure due to the increasing number of steel structures reaching the end of their design life each year. Increased loadings, deterioration due to weathering, climate change and human error also negatively impact the design life. Rehabilitating steel bridge girders rather than replacing the existing structure can provide an option for an economical and sustainable future. This paper presents the results of an experimental study which implements a simple retrofitting technique to combat fatigue failure. The retrofitting technique is applied to girders which have incurred fatigue cracking within the bottom flange. Experimental tests are performed on a riveted tapered 120-year-old girder and a new prefabricated hot rolled girder. The results from the experimental tests showed that fatigue cracking within the bottom flange of girders can be easily rehabilitated to increase the girder’s capacity to that of their original design. By utilising this simple designed retrofitting technique, existing structures do not need to be replaced. The technique shown herein is a viable method for increasing the service life of steel girders providing for a sustainable future

Blood transfusion practice in surgery at Bugando Medical Centre in northwestern Tanzania

 Background: Preoperative over-ordering of blood for surgical intervention, in excess of the actual and anticipated needs is a common practice in many developing countries. This can be decreased by simple means of changing the blood cross matching and ordering schedule depending upon the type of surgery performed. The aim of this study was to assess the blood transfusion practice in surgery at Bugando Medical Centre in northwestern Tanzania.Methods and Patients: This was a prospective cross sectional study among patients undergoing major operations at Bugando Medical Centre. We evaluated blood ordering and transfusion practices in emergency and elective surgical procedures at our centre and calculated different indices such as cross-match to transfusion ratio (C/T ratio), transfusion probability (% T) and transfusion index (TI). Next Maximal Surgical Blood Ordering System (MSBOS) was estimated for each procedure.Results: The overall blood utilization was only 28.2% at our centre, consisting of 17.1% in the elective operations and 26.9% in the emergency operations. Significant blood utilization was nil in most of the routine elective cases suggesting cross-matching of blood to be a culture than necessity. Generally, the overall blood transfusion of the requested blood as indicated by indices of C/T ratio, %T, TI and MSBOS were 3.5, 28.7%, 0.33 and 0.45, respectively. The overall CT ratio, %T, Ti and MSBOS in the elective operations were 5.8, 15.9%, 0.2 and 0.3, respectively. In the emergency operations, the overall CT ratio, %T, Ti and MSBOS were 3.7, 22%, 0.32 and 0.48, respectively.Conclusion: This study demonstrated that over-ordering of blood in excess of the actual needs is a common practice in our setting.  Blood ordering pattern needs to be revised and over-ordering of blood should be minimized. This can be possible by the estimation of MSBOS for each procedure and requisition as calculated

Generation of Realistic Synthetic Raw Radar Data for Automated Driving Applications using Generative Adversarial Networks

The main approaches for simulating FMCW radar are based on ray tracing, which is usually computationally intensive and do not account for background noise. This work proposes a faster method for FMCW radar simulation capable of generating synthetic raw radar data using generative adversarial networks (GAN). The code and pre-trained weights are open-source and available on GitHub. This method generates 16 simultaneous chirps, which allows the generated data to be used for the further development of algorithms for processing radar data (filtering and clustering). This can increase the potential for data augmentation, e.g., by generating data in non-existent or safety-critical scenarios that are not reproducible in real life. In this work, the GAN was trained with radar measurements of a motorcycle and used to generate synthetic raw radar data of a motorcycle traveling in a straight line. For generating this data, the distance of the motorcycle and Gaussian noise are used as input to the neural network. The synthetic generated radar chirps were evaluated using the Frechet Inception Distance (FID). Then, the Range-Azimuth (RA) map is calculated twice: first, based on synthetic data using this GAN and, second, based on real data. Based on these RA maps, an algorithm with adaptive threshold and edge detection is used for object detection. The results have shown that the data is realistic in terms of coherent radar reflections of the motorcycle and background noise based on the comparison of chirps, the RA maps and the object detection results. Thus, the proposed method in this work has shown to minimize the simulation-to-reality gap for the generation of radar data