Leukaemia following childhood radiation exposure in the Japanese atomic bomb survivors and in medically exposed groups

Incidence and mortality risks of radiation-associated leukaemia are surveyed in the Japanese atomic bomb (A-bomb) survivors exposed in early childhood and in utero. Leukaemia incidence and mortality risks are also surveyed in 16 other studies of persons who received appreciable doses of ionizing radiation in the course of treatment in childhood and for whom there is adequate dosimetry and cancer incidence or mortality follow-up. Relative risks tend to be lower in the medical series than in the Japanese A-bomb survivors. The relative risks in the medical studies tend to diminish with increasing average therapy dose. After taking account of cell sterilisation and dose fractionation, the apparent differences between the relative risks for leukaemia in the Japanese A-bomb survivors and in the medical series largely disappear. This suggests that cell sterilisation largely accounts for the discrepancy between the relative risks in the Japanese data and the medical studies. Excess absolute risk has also been assessed in four studies, and there is found to be more variability in this measure than in excess relative risk. In particular, there is a substantial difference between the absolute risk in the Japanese atomic bomb survivor data and those in three other (European) populations. In summary, the relative risks of leukaemia in studies of persons exposed to appreciable doses of ionizing radiation in the course of treatment for a variety of malignant and non-malignant conditions in childhood are generally less than those in the Japanese A-bomb survivor data. The effects of cell sterilisation can largely explain the discrepancy between the Japanese and the medical series.     

Meta-analysis of second cancer risk after radiotherapy among childhood cancer survivors

Cancer risks among childhood cancer survivors following radiotherapy have not yet been well characterised in terms of radiation dose. A meta-analysis of studies on the excess relative risk per gray (ERR) of second cancer was conducted previously; unfortunately, the small number of eligible studies restricted quantitative evaluations. To solve this problem, a statistical method to calculate ERR estimates from other estimates was developed, and a meta-analysis was conducted again. The PubMed database was searched and 26 relevant studies were identified. ERR estimates were available in 15 studies, and for the other 11 studies, the regression-based model was used to calculate ERR estimates from other estimates. The overall ERR estimate was 0.40, which was much lower than that of atomic bomb survivors exposed as young children. Heterogeneity of the risk among studies was suggested, and a further study is needed to explore the heterogeneity among studies.     

Problems in the rational analysis of transportation safety

Analysis of air traffic control capacity shows the relation between traffic level and risk can be dealt with quantitatively only if units of risk are specified. Measuring risk in terms of fatalities per hour of exposure solves the major problem of how to compare the effects that many different kinds of risk have upon patterns of human activity, but leaves us with a number of unresolved secondary issues. Among these are : incommensurability of certain risks, failure of statistical independence, certain limitations of time-normalization, unequal distribution of costs and benefits, different weighting of voluntary and involuntary risks, liability, cost and value of uncertainty, positive value of some risks, acceptability of unequal risks, difficulty of estimating very small probabilities and threat of the unknown compared to threat of the known. Although these issues arose out of air traffic control studies, they are clearly relevant to risk analyses of many other systems.     

Preconception exposures to potential germ-cell mutagens

Radiation and other agents can cause germ-cell mutations in animal systems. No human germ-cell mutagen has been identified, but this does not mean that human germ-cells are not vulnerable to mutagenesis. There has been particular concern about the possible health effects on offspring following parental preconception exposure to ionizing radiation-both occupational and therapeutic. A strong association with preconception radiation exposure in the fathers of the cases was found in a case-control study of young people with leukaemia living near the Sellafield nuclear plant in the UK. Subsequent studies of workers occupationally exposed to ionizing radiation have failed to confirm these findings. No statistically significant effects have been reported from studies of possible indicators of germ-cell mutagenesis in the A-bomb survivors. Studies of offspring of cancer survivors who receive radiotherapy and mutagenic chemotherapy have found no evidence of germ-cell mutagenesis. Failure to detect human germ-cell mutagenic agents may be a consequence of inadequate study sizes or insufficiently sensitive laboratory techniques.     

The use of biologically based cancer risk models in radiation epidemiology

Biologically based risk projection models for radiation carcinogenesis seek to describe the fundamental biological processes involved in neoplastic transformation of somatic cells into malignant cancer cells. A validated biologically based model, whose parameters have a direct biological interpretation, can also be used to extrapolate cancer risks to different exposure conditions with some confidence. In this article biologically based models for radiation carcinogenesis, including the two-stage clonal expansion (TSCE) model and its extensions, are reviewed. The biological and mathematical bases for such models are described, and the implications of key model parameters for cancer risk assessment examined. Specific applications of versions of the TSCE model to important epidemiological datasets are discussed, including the Colorado uranium miners' cohort; a cohort of Chinese tin miners; the lifespan cohort of atomic bomb survivors in Hiroshima and Nagasaki; and a cohort of over 200,000 workers included in the National Dose Registry (NDR) of Canada.     

A new view of radiation-induced cancer

Biologically motivated mathematical models are important for understanding the mechanisms of radiation-induced carcinogenesis. Existing models fall into two categories: (1) short-term formalisms, which focus on the processes taking place during and shortly after irradiation (effects of dose, radiation quality, dose rate and fractionation), and (2) long-term formalisms, which track background cancer risks throughout the entire lifetime (effects of age at exposure and time since exposure) but make relatively simplistic assumptions about radiation effects. Grafting long-term mechanisms on to short-term models is badly needed for modelling radiogenic cancer. A combined formalism was developed and applied to cancer risk data in atomic bomb survivors and radiotherapy patients and to background cancer incidence. The data for nine cancer types were described adequately with a set of biologically meaningful parameters for each cancer. These results suggest that the combined short-long-term approach is a potentially promising method for predicting radiogenic cancer risks and interpreting the underlying biological mechanisms.     

Effect of pre-treatments on hydrolysis and methane production potentials of by-products from meat-processing industry

Language issues are problems with communication via speech, signs, gestures or their written equivalents. They may result from poor reading and writing skills, a mix of foreign languages and other circumstances. Language issues are not picked up as a safety risk on the shop floor by current safety management systems. These safety risks need to be identified, acknowledged, quantified and prioritised in order to allow risk reducing measures to be taken. This study investigates the nature of language issues related danger in literature, by experiment and by a survey among the Seveso II companies in the Netherlands. Based on human error frequencies, and on the contents of accident investigation reports, the risks associated with language issues were ranked. Accident investigation method causal factor categories were found not to be sufficiently representative for the type and magnitude of these risks. Readability of safety related documents used by the companies was investigated and found to be poor in many cases. Interviews among regulators and a survey among Seveso II companies were used to identify the gap between the language issue related dangers found in literature and current best practices. This study demonstrates by means of triangulation with different investigative methods that language issue related risks are indeed underestimated. A recommended coarse of action in order to arrive at appropriate measures is presented.     

Ageing drivers: storm in a teacup?

The purpose of this paper is to address two important issues regarding ageing drivers. First, there is a presumption in the road safety arena that the expected increase in the number of ageing drivers on the roads will lead to an increase in crashes. Second, despite extensive research on ageing drivers, especially on their increased vulnerability and reduced driving abilities, the most widely recommended road safety strategy relates to the control of their driving licenses. This presumption and the associated policy recommendation are based mainly on the higher relative crash risks associated with ageing drivers compared to their younger counterparts. This study, however, argues that the average crash risks obtained in previous studies provide only indirect information concerning these issues and any decision based on these results may produce unexpected outcomes. An analytical framework to examine the marginal effect of changing the driver mix on the roads is proposed and a simple empirical model is estimated as an illustration. In contrast to previous studies, we found that increasing the number of licenses issued to ageing drivers had only an insignificant impact on the number of fatal crashes on the roads, suggesting that the concern over ageing drivers may be a storm in a teacup.     

Disinfection byproducts in Canadian provinces: associated cancer risks and medical expenses

Chlorination for drinking water forms various disinfection byproducts (DBPs). Some DBPs are probably linked to human cancer (e.g., bladder, colorectal cancers) and other chronic and sub-chronic effects. This emphasizes the need to understand and characterize DBPs in drinking water and possible risks to human health. In this study, occurrences of DBPs throughout Canada were investigated. Trihalomethanes (THMs) were observed to be highest in Manitoba followed by Nova Scotia and Saskatchewan, while haloacetic acids were highest in Nova Scotia followed by Newfoundland and Labrador. Based on the characterization of DBPs, risk of cancer from exposure to THMs was predicted using ingestion, inhalation and dermal contact pathways of exposure. In Canada, approximately 700 cancer cases may be caused by exposure to THMs in drinking water. Medical expenses associated with these cancer incidents are estimated at some $140 million/year. Expense may be highest in Ontario (～$47 million/year) followed by Quebec (～$25 million/year) due to a greater population base. This paper suggests improvements in water treatment, source protection and disinfection processes, and caution in the use of alternative disinfectants to reduce DBPs. Finally, elements are provided to mitigate risks and reduce cost estimates in future studies.     

A review of some epidemiological studies on cancer risk from low-dose radiation or other carcinogenic agents

It is extremely difficult to assess cancer risks accurately due to health effects of low-dose radiation exposure or other carcinogens based on epidemiological studies. For the detection of minute increases of the risk at low-level exposure, most of epidemiological studies lack statistical power, and they involve various complicated confounding factors. This paper reports on a literature survey of epidemiological studies published since 2000 on cancer risks associated with low-dose radiation and other carcinogens to gather major epidemiological data. Integrated risk indices were derived from those data by using, where possible, statistical models. Regarding risk assessment of low-dose radiation exposure, it is important to lower the degree of uncertainty arising from risk estimation. Risk assessment of low-dose radiation exposure could be scientific evidence when uncertainty is considered in comparing carcinogenic risks of radiation with those of other carcinogens.     

A GIS-based evaluation of risks due to trihalomethane exposure during showering in coastal Texas

Disinfection of water supplies with chlorine is essential to water treatment, but can lead to the formation of trihalomethanes (THMs) in the presence of natural organic matter. Exposure to THMs via inhalation during daily activities such as showering can significantly increase cancer risks. An innovative decision support system was developed for evaluating THM exposure and risks in water supplies in the Gulf Coast region of Texas by combining a shower THM volatilization model, geospatial analysis techniques, and risk assessment methodologies. Based on THM data from fourteen locations in the region, a power-law equation was developed to predict the formation of THMs in groundwater wells. Health risks associated with THMs in the water supplies of the Gulf Coast of Texas were evaluated. Cancer risks were found to vary from 7.14?×?10^?7 to 7.75?×?10^?6. While two-thirds of the geographical area was below the threshold risk of 1?×?10^?6, it accounted for only a tenth of the total population. Metropolitan areas such as Corpus Christi and McAllen, which currently use surface water sources, and Houston, which is seeking alternate water sources due to subsidence issues, were found to have significant cancer risks (in excess of one in a million). A third of the population of Texas is housed in the Gulf Coast region, and with more population migration toward the metropolitan areas, it is recommended that water resource management decisions be made taking into consideration both the quantity and quality of water available.     

Strategic supply chain management issues in the automotive industry: an Australian perspective

The automotive manufacturing industry is an extremely competitive one. Many companies are focusing on their supply chains for sources of competitive advantage. This paper presents the findings of an exploratory study that examined contemporary issues related to supply chains in the Australian automotive manufacturing industry. Data from interviews with managers from vehicle manufacturers, component suppliers, peak industry bodies and government agencies enabled the articulation of 10 key issues. These issues were validated as being relevant to the industry by another group of managers from the industry. Review of these 10 issues showed that the relationships between the parties in supply chains are complex, and despite the success of the industry, there are a number of structural weaknesses. These issues, when taken individually, pose significant risks to the industry. When considered collectively, these risks are magnified several fold. This paper also presents research questions in the form of formal propositions associated with the 10 issues that need to be rigorously tested in order to assess the long-term viability and success of the industry. The issues that are raised can also be relevant to other industries with similar supply chain dynamics.     

Biological parameters for lung cancer in mathematical models of carcinogenesis

Applications of the two-step model of carcinogenesis with clonal expansion (TSCE) to lung cancer data are reviewed, including those on atomic bomb survivors from Hiroshima and Nagasaki. British doctors, Colorado Plateau miners and Chinese tin miners. Different sets of identifiable model parameters are used in the literature. The parameter set which could be determined with the lowest uncertainty consists of the net proliferation rate gamma of intermediate cells, the hazard h55 at an intermediate age and the hazard h(infinity) at an asymptotically large age. Also, the values of these three parameters obtained in the various studies are more consistent than other identifiable combinations of the biological parameters. Based on representative results for these three parameters, implications for the biological parameters in the TSCE model are derived.     

A methodology for controlling dispersion in food production and distribution

After a number of food safety crises, the design and implementation of traceability systems became an important tool for managing safety risks in the food industry. In the literature, numerous studies deal with traceability from the viewpoint of information system and technology development. However, traceability and its implications for food safety receive less attention in literature on production and distribution planning. From the viewpoint of operations management, an efficient management of food safety risks requires the consideration of the amounts of potentially recalled products, affected regions/customers, and logistics efforts connected to solving the safety problem. In this paper we are developing a production and distribution planning model for food supply chains to address these issues. We also present heuristics for solving the resulting mixed-integer linear programming model and demonstrate the effectiveness of the developed methodology in a numerical investigation.     

Current status of gamma Ti aluminides for aerospace applications

New technology is implemented when the perceived technical risks are outweighed by the perceived marketing risks of not using the technology. Although great strides have been made in reducing the technical risks of gamma titanium aluminide, considerable uncertainty remains regarding the economic and marketing issues.     

An interactive risk visualisation tool for large-scale and complex engineering and construction projects under uncertainty and interdependence

Implementation of the megaprojects with large-scale engineering and construction projects are risky in nature and evaluating the associated risks of those large projects is a critical success factor. The systematic approaches and empirical studies related to the visualisation and communicating risks of these projects remain missing. This paper aims to develop a systematic approach to managing and visualising the risk of these mega-projects using joint application of fuzzy group decision-making, analytic network process and mapping the resulting network of dependencies together with proximity information, graph theory, and mutual information theory. We have applied the model in a real case study of megaprojects in the oil and gas industry. The methodology proposed in this study could be used in the other large-scale engineering and construction projects considering the contracts features and the contextual factors.     

Review of supplier diversification and pricing strategies under random supply and demand

Uncertainties of supply and demand are two major sources of risk in any supply chain. As a result, the companies are implementing different strategies to mitigate the effects of these risks. Supplier diversification and responsive pricing are two of the main strategies that are used to mitigate the supply and demand risks. In supplier diversification, a firm uses multiple channels of sourcing while in responsive pricing, a firm manipulates demand through pricing to mitigate supply and demand risks. In this paper, we review lot-sizing problems when supply and demand are random. We focus on studies that have considered supplier diversification or responsive pricing as a mitigation strategy. We classify the studies based on their main assumptions and summarise their major findings. Finally, we present some directions for future research. Part of what we have found is that most studies that use multiple decision makers have focused on cases where information is complete and non-cooperative. There is a need to consider more realistic situations when there is information asymmetry between the decision makers. In addition, we have found that there is a lack of studies that look at the impact of joint ordering and pricing in the existence of multiple suppliers.     

Radiations in space: risk estimates

The complexity of radiation environments in space makes estimation of risks more difficult than for the protection of terrestrial populations. In deep space the duration of the mission, position in the solar cycle, number and size of solar particle events (SPE) and the spacecraft shielding are the major determinants of risk. In low-earth orbit missions there are the added factors of altitude and orbital inclination. Different radiation qualities such as protons and heavy ions and secondary radiations inside the spacecraft such as neutrons of various energies, have to be considered. Radiation dose rates in space are low except for short periods during very large SPEs. Risk estimation for space activities is based on the human experience of exposure to gamma rays and to a lesser extent X rays. The doses of protons, heavy ions and neutrons are adjusted to take into account the relative biological effectiveness (RBE) of the different radiation types and thus derive equivalent doses. RBE values and factors to adjust for the effect of dose rate have to be obtained from experimental data. The influence of age and gender on the cancer risk is estimated from the data from atomic bomb survivors. Because of the large number of variables the uncertainities in the probability of the effects are large. Information needed to improve the risk estimates includes: (1) risk of cancer induction by protons, heavy ions and neutrons: (2) influence of dose rate and protraction, particularly on potential tissue effects such as reduced fertility and cataracts: and (3) possible effects of heavy ions on the central nervous system. Risk cannot be eliminated and thus there must be a consensus on what level of risk is acceptable.     

Risks of modular integrated construction: A review and future research directions

Stakeholders remain skeptical in adopting modular integrated construction (MiC) because of the associated risks and uncertainties, although its benefits have been extensively documented. The unique business model of MiC nurtures several risks and uncertainties different from those of the conventional construction approach. Despite the growing attention on MiC with its market expansion, no systematic evaluation is in place to monitor its risks research progress. Accordingly, this research reviewed published literature addressing the risks associated with MiC from 1992 to 2019. Analysis reveals that the research publications on risks of MiC witnessed a steady growth, with considerable progress occurring in the last decade. Result implies that the risk of MiC has gained extra attention in the construction engineering and management domain in recent times. Existing empirical studies have focused heavily on perceived implementation risks, supply chain risks, schedule risks, investment risks, structural risks, ergonomic risks, and MiC risk management strategies, which indicate that MiC is associated with a host of risk events. The research further identified the critical risk events (CREs) in the application of MiC based on frequency of occurrence. The identified CREs contributes to the checklists of risk events in the implementation of offsite construction (OSC). The latter may be useful in risk planning, especially where the MiC is less developed, and fewer or no bespoke risk assessment exists. Research gaps in existing studies are highlighted in this research, and areas for further studies are then proposed. Thus, it makes a useful contribution to the scholarly literature on the risk of OSC and may prove useful to offsite construction researchers, industry practitioners, and project managers.     

A Review of 3D Printing Technology for Medical Applications

Donor shortages for organ transplantations are a major clinical challenge worldwide. Potential risks that are inevitably encountered with traditional methods include complications, secondary injuries, and limited source donors. Three-dimensional (3D) printing technology holds the potential to solve these limitations; it can be used to rapidly manufacture personalized tissue engineering scaffolds, repair tissue defects in situ with cells, and even directly print tissue and organs. Such printed implants and organs not only perfectly match the patient’s damaged tissue, but can also have engineered material microstructures and cell arrangements to promote cell growth and differentiation. Thus, such implants allow the desired tissue repair to be achieved, and could eventually solve the donor-shortage problem. This review summarizes relevant studies and recent progress on four levels, introduces different types of biomedical materials, and discusses existing problems and development issues with 3D printing that are related to materials and to the construction of extracellular matrix in vitro for medical applications.