Visfatin versus Flow-Mediated Dilatation as a Marker of Endothelial Dysfunction in Pediatric Renal Transplant Recipients

BACKGROUND: Renal transplantation (RTx) is the treatment of choice for paediatric end-stage renal disease (ESRD). A major cause of morbidity and mortality after RTx is cardiovascular disease. Independent predictors of cardiovascular events were shown to constitute an endothelial dysfunction (ED). This study aims to evaluate Visfatin serum level in comparison to brachial artery flow-mediated dilatation (FMD) as a marker of endothelial dysfunction in paediatric RTx recipients.METHODS: Visfatin serum level has been evaluated in 30 patients on regular hemodialysis (HD), 36 patients post-RTx and 30 controls as a measure for ED, and has been compared to brachial artery FMD.RESULTS: Visfatin level in transplant recipients was significantly lower than the hemodialysis group as well as FMD was better in transplant recipients. In spite of marked improvement of FMD and marked reduction of visfatin in post-RTx no direct statistical correlation was found between serum Visfatin level and flow-mediated dilatation.CONCLUSION: Pediatric RTx recipients show lower serum Visfatin level and better FMD than those on regular hemodialysis, reflecting less endothelial dysfunction (ED) and less cardiovascular risk. FMD in kidney transplant recipients tends to be less than normal subjects while visfatin level of the same group is similar to controls. Pediatric RTx appears to have a positive impact on the growth development of children with ESRD

A Survey of Tractors and Tires Types in Some Southern Farms of Saudi Arabia

Seventy farms from Samttah, Southern Zone of Saudi Arabia, were surveyed during on-farm visits to identify the tractor models and power. tractor age and accumulated working hOUfS, and number of tractors in the farm. Data was also collected concerning the tractor tire inflation pressures, tire condition, and tire sizes. The results were compared with the manufacturer's recommendation of service and operation. Average farm area was 14.9 ha, 10% of the farms owned two tractors with an average power of 52.9 kW, 91 % of the tractors power were over 50 kW and 93.5% of the tractors were 2WD and the rest were MFWD. Average tractor age was 7 years old with an average of 1020 working hours per year. Massey Ferguson agricultural tractors was the most popular type in the region (64.9%) and had six different models. The oldest tractor was 15 years old. It was also found that most of tractors using either new or good condition tires, while 30% of the tires were cut or worn-out tire

Farm tractors breakdown classificati

Work orders for 40 tractors, collected by Hail Agricultural Development Company (HADCO), Saudi Arabia, were used in this study. Data for more than 1670 work orders were classified as repairs or maintenance. The relationship between tractor age and power on repair and maintenance costs was also investigated. A cost ratio (CR) term was developed by dividing the repair or maintenance cost by the tractor purchase price. This CR was used in all variables affected the repairs and maintenance costs. 51% of the work orders were classified as repair works while 49% were classified as maintenance jobs. The highest CRs were listed for both repair and maintenance. The 64 WJOs for transmission repairs had the highest CR, while electrical system repairs WJOs were 197 and had the lowest CR. That is because the costs of some parts were much affecting the CR and not the number of work orders. Similar results were obtained when calculating the classified maintenance CR. The repair CR was higher than that of the maintenance. Both repair CR and maintenance CR were directly related to tractor working life (age) and tractor power

Repair and Maintenance Cost Models for Combines in Saudi Arabia

Objective of this study was to develop repair and maintenance cost models for combines in Hail Agricultural Development Company (HADCO), Saudi Arabia. Three exponential models were developed. The general form of the model is: where: A.T.C.: ratio of accumulated repair and maintenance cost to the machine list price, N: accumulated engine working hours divided by 1000; or, accumulated separator working hours divided by 1000; or, percentage of machine age to it's wear¬out life. Results showed that any of these models could be used if one of the independent variables (N) is known. The first model estimated the costs when some or all machine moving parts were operating, while the second model calculate the costs when all parts were operating. This was mainly due to preparing the combine or long transportation from one location to another. Unfortunately, there was no previous studies concerning this point and further detailed investigation is needed. A comparison was made between the first model and similar models obtained by other studies. It was found that the developed model gave the least cost compared with other models due to the fact that it was developed using accurate records of one huge project. It is recommended that the use of mathematical models developed for combines repair and maintenance be used to those areas which they were developed for, or very similar in costs of spare parts and labo

A Preliminary Study on Greenhouses Farm Mechanization in Saudi Arabia

In the last ten years, the practice of greenhouse farming has been used on a large scale in the kingdom of Saudi Arabia. The agriculture production of most of these greenhouses was directed to the production of vegetable crops because of their high profit and the relatively short season. Data were collected from greenhouses farms in the central region of the Kingdom. The collected data included a survey of mechanical and manual operations, house dimensions, operations and machines used, and machinery operating patterns inside the houses. The measurements included working width and operating and non-operating times. Actual operating speed was determined as well as field capacity and field efficiency for the various mechanical and manual operations. The average operating speeds was 3.28, 2.65, 1.97, 4.1 and 0.83 km/hr for plowing, cultivating, ridging, line opening, and spraying respectively. It was found that the speed of tillage operations was less than that of the speeds in the open fields by 60¬80%. This also was reflected on the values of field efficiency which was very low in specific for plowing, cultivating and ridging. The average values was 60.7, 53.1, and 57.1 %, while the actual field capacity for the same operations was as follow: 0.298. 0.184 and 0.166 ha/hr. The field efficiency and field capacity was directly affected by the Lower speeds as well as other factors such as: improper size of tractor and machine, the orientation of the house, the operating pattern and the obstacles inside the house