Assessing the roll stability of heavy vehicles in South Africa

In South Africa there are approximately 12.5 truck-crash-related fatalities per 100 million kilometres travelled. This is between 4 and 10 times higher than a number of European countries such as Denmark, France, Germany and Switzerland and many of these crashes involve heavy vehicle rollover. The regulations in the National Road Traffic Act of South Africa that govern heavy vehicle design do not directly address the roll stability of heavy vehicles. The internationally accepted method of regulating roll stability is by means of a static rollover threshold (SRT) assessment or test, to determine the maximum lateral acceleration that a vehicle can withstand before rolling over. The SRT is determined by physical testing, or through multibody dynamics simulation; however, both of these approaches are costly and time-consuming. This paper considers various simplified tools to estimate the SRT of articulated heavy vehicles, and compares the results to SRT values determined using multibody dynamics simulation. The simplified tool as described by the New Zealand Land Transport Rule was identified as the most viable technique to potentially regulate the roll stability of heavy vehicles in South Africa.Paper presented at the 35th Annual Southern African Transport Conference 4-7 July 2016 "Transport ? a catalyst for socio-economic growth and development opportunities to improve quality of life", CSIR International Convention Centre, Pretoria, South Africa.The Minister of Transport, South AfricaTransportation Research Board of the US

A pro-forma design for car-carriers : low-speed performance-based standards

The Australian performance-based standards (PBS) scheme is being evaluated in South Africa as an alternative means of regulating heavy vehicles, allowing for a relaxation of length and mass limits. This has proven to provide economic benefits while improving vehicle safety and emissions. Within the PBS scheme, the vehicle is assessed using twelve performance standards which can be grouped together as low-speed directional, high-speed directional, stability and longitudinal performance measures. Compliance with these standards requires expensive and time-intensive computer simulations; a hurdle to the car-carrier industry in particular. We propose a pro-forma car-carrier design in which limits on the most important car-carrier parameters are defined to ensure compliance with the low-speed PBS. It is proposed that new car-carrier designs complying with this semi-prescriptive pro-forma design be exempted from full PBS assessment in the South African PBS project. In this paper the parametric sensitivity of the low-speed performance standards was assessed, and suitable limits on these parameters were found. Tests were carried out on hypothetical designs within these limits. It was found that each of the 10 000 vehicle configurations generated within the constraints of the pro-forma design met the Level 1 requirements of the low-speed PBS. Future work will ensure compliance with the full set of twelve performance standards. It is estimated that the pro-forma approach as compared to doing full assessments would save the South African car-carrier industry an estimated R1,200,000 in one year.Paper presented at the 34th Annual Southern African Transport Conference 6-9 July 2015 "Working Together to Deliver - Sakha Sonke", CSIR International Convention Centre, Pretoria, South Africa.The Minister of Transport, South AfricaTransportation Research Board of the US

An automated Fpg-based FADU method for the detection of oxidative DNA lesions and screening of antioxidants

The oxidation of guanine to 8-oxo-2′-deoxyguanosine (8-oxo-dG) is one of the most abundant and best studied oxidative DNA lesions and is commonly used as a biomarker for oxidative stress. Over the last decades, various methods for the detection of DNA oxidation products have been established and optimized. However, some of them lack sensitivity or are prone to artifact formation, while others are time-consuming, which hampers their application in screening approaches. In this study, we present a formamidopyrimidine glycosylase (Fpg)-based method to detect oxidative lesions in isolated DNA using a modified protocol of the automated version of the fluorimetric detection of alkaline DNA unwinding (FADU) method, initially developed for the measurement of DNA strand breaks (Moreno-Villanueva et al., 2009. BMC Biotechnol. 9, 39). The FADU-Fpg method was validated using a plasmid DNA model, mimicking mitochondrial DNA, and the results were correlated to 8-oxo-dG levels as measured by LC–MS/MS. The FADU-Fpg method can be applied to analyze the potential of compounds to induce DNA strand breaks and oxidative lesions, as exemplified here by treating plasmid DNA with the peroxynitrite-generating molecule Sin-1. Moreover, this method can be used to screen DNA-protective effects of antioxidant substances, as exemplified here for a small-molecule, i.e., uric acid, and a protein, i.e., manganese superoxide dismutase, both of which displayed a dose-dependent protection against the generation of oxidative DNA lesions. In conclusion, the automated FADU-Fpg method offers a rapid and reliable measurement for the detection of peroxynitrite-mediated DNA damage in a cell-free system, rendering it an ideal method for screening the DNA-protective effects of antioxidant compounds.Deutsche Forschungsgemeinschaft (Grant BU 698/6-1)National Institutes of Health (U.S.) (Grant ES002109)National Institutes of Health (U.S.) (Grant CA026731

Perceptions of the road transport management system (RTMS) : promoting voluntary certification

This paper uses a structured survey to provide insight into how the Road Transport Management System (RTMS), SABS standard SANS 1395:2014, has developed and is viewed within the road transport industry in South Africa. The RTMS is an industry-led, government-supported, voluntary, self-regulation scheme that encourages consignees, consignors and road transport operators to implement a management system that demonstrates compliance with road traffic regulations and contributes to preserving road infrastructure, improving road safety and increasing productivity. The surveyed views of the road traffic authorities, banks, insurance companies, the RTMS steering committee, and road transport operators provide insights into the perceptions and experiences with respect to the RTMS from diverse stakeholders. Respondents indicate that improved safety, operational efficiency and reduced road crashes are seen as attractive benefits to implementing the RTMS. The main obstacles to certification are a lack of awareness of the RTMS and a poor understanding of the requirements for becoming RTMS certified. The clients of road transporters play a significant role in the transporter’s decision to become RTMS certified.Papers presented at the 36th Southern African Transport Conference, CSIR International Convention Centre, Pretoria, South Africa on 10-13 July 2017.Transportation research board of the national academie

In vivo methylation of mtDNA reveals the dynamics of protein–mtDNA interactions

To characterize the organization of mtDNA–protein complexes (known as nucleoids) in vivo, we have probed the mtDNA surface exposure using site-specific DNA methyltransferases targeted to the mitochondria. We have observed that DNA methyltransferases have different accessibility to different sites on the mtDNA based on the levels of protein occupancy. We focused our studies on selected regions of mtDNA that are believed to be major regulatory regions involved in transcription and replication. The transcription termination region (TERM) within the tRNALeu(UUR) gene was consistently and strongly protected from methylation, suggesting frequent and high affinity binding of mitochondrial transcription termination factor 1 (mTERF1) to the site. Protection from methylation was also observed in other regions of the mtDNA, including the light and heavy strand promoters (LSP, HSP) and the origin of replication of the light strand (OL). Manipulations aiming at increasing or decreasing the levels of the mitochondrial transcription factor A (TFAM) led to decreased in vivo methylation, whereas manipulations that stimulated mtDNA replication led to increased methylation. We also analyzed the effect of ATAD3 and oxidative stress in mtDNA exposure. Our data provide a map of human mtDNA accessibility and demonstrate that nucleoids are dynamically associated with proteins

Manganese Superoxide Dismutase: Guardian of the Powerhouse

The mitochondrion is vital for many metabolic pathways in the cell, contributing all or important constituent enzymes for diverse functions such as β-oxidation of fatty acids, the urea cycle, the citric acid cycle, and ATP synthesis. The mitochondrion is also a major site of reactive oxygen species (ROS) production in the cell. Aberrant production of mitochondrial ROS can have dramatic effects on cellular function, in part, due to oxidative modification of key metabolic proteins localized in the mitochondrion. The cell is equipped with myriad antioxidant enzyme systems to combat deleterious ROS production in mitochondria, with the mitochondrial antioxidant enzyme manganese superoxide dismutase (MnSOD) acting as the chief ROS scavenging enzyme in the cell. Factors that affect the expression and/or the activity of MnSOD, resulting in diminished antioxidant capacity of the cell, can have extraordinary consequences on the overall health of the cell by altering mitochondrial metabolic function, leading to the development and progression of numerous diseases. A better understanding of the mechanisms by which MnSOD protects cells from the harmful effects of overproduction of ROS, in particular, the effects of ROS on mitochondrial metabolic enzymes, may contribute to the development of novel treatments for various diseases in which ROS are an important component