Falls are a significant public health risk and a leading cause of non-fatal and fatal injuries among construction workers worldwide. A more comprehensive understanding of casual factors leading to fall incidents is essential to prevent falls in the construction industry. However, an extensive overview of causal factors is missing from the literature. In this paper, 536 articles on factors contributing to the risk of falls were retrieved. One hundred and twenty-one (121) studies met the criteria for relevance and quality to be coded, and were synthesized to provide an overview. In lieu of the homogeneity needed across studies to conduct a structured meta-analysis, a literature synthesis method based on macro-variables was advanced. This method provides a flexible approach to aggregating previous findings and assessing agreement across those studies. Factors commonly associated with falls included working surfaces and platforms, workers' safety behaviours and attitudes, and construction structure and facilities. Significant differences across qualitative and quantitative studies were found in terms of focus, and areas with limited agreement in previous research were identified. The findings contribute to research on the causes of falls in construction, developing engineering controls, informing policy and intervention design to reduce the risk of falls, and improving research synthesis methods.Accident causes, causal map, literature synthesis methods, safety,
Up-converting phosphor technology (UPT)-based lateral-flow immunoassay has been developed for quantitative detection of Yersinia pestis rapidly and specifically. In this assay, 400 nm up-converting phosphor particles were used as the reporter. A sandwich immumoassay was employed by using a polyclonal antibody against F1 antigen of Y. pestis immobilized on the nitrocellulose membrane and the same antibody conjugated to the UPT particles. The signal detection of the strips was performed by the UPT-based biosensor that could provide a 980 nm IR laser to excite the phosphor particles, then collect the visible luminescence emitted by the UPT particles and finally convert it to the voltage as a signal. V T and V C stand for the multiplied voltage units for the test and the control line, respectively, and the ratio V T /V C is directly proportional to the number of Y. pestis in a sample. We observed a good linearity between the ratio and log CFU/ml of Y. pestis above the detection limit, which was approximately 10 4 CFU/ml. The precision of the intra-and inter-assay was below 15% (coefficient of variation, CV). Cross-reactivity with related Gram-negative enteric bacteria was not found. The UPT-LF immunoassay system presented here takes less than 30 min to perform from the sample treatment to the data analysis. The current paper includes only preliminary data concerning the biomedical aspects of the assay, but is more concentrated on the technical details of establishing a rapid manual assay using a state-of-the-art label chemistry.
A total of 110 strains of Klebsiella pneumoniae were used to optimize pulsed-field gel electrophoresis (PFGE) for subtyping of K. pneumoniae. For optimization of electrophoresis parameters (EPs) of XbaI-PFGE, 11 isolates were analyzed with XbaI digestion using three EPs. The EP of a switch time of 6 to 36 s for 18.5 h gave clearest patterns and was declared the optimal EP for XbaI PFGE of K. pneumoniae. By software analysis and pilot study, AvrII was chosen as another PFGE enzyme. Both XbaI- and AvrII-PFGE gave D-values higher than 0.99 for 69 K. pneumoniae isolated from different sources. Our results also showed good typeability, reproducibility of both XbaI- and AvrII-PFGE for K. pneumoniae subtyping. Furthermore, the established PFGE method also had good discriminatory power to distinguish outbreak K. pneumoniae strains and a high degree of consistency with multilocus sequence typing method. A rapid PFGE protocol was established here, which could be used for genotyping and other researches of K. pneumoniae.
The rework cycle is at the heart of modeling projects, one of the major research and application areas in system dynamics. The current formulations for the rework cycle assume each task is either defective or not. Yet in many projects multiple defects can occur in one task. In this study we introduce a new rework cycle formulation that accounts for multiple defects per task and fl exibly captures the testing process. We compare this formulation with two established formulations from the literature. Analysis shows some differences in simulated projects' fi nish time and delivered quality across different models and we discuss how these differences depend on project characteristics and task structure. The new formulation could be especially useful when data on tasks, defects, and testing have different measures, and when each new defect in a task signifi cantly increases the chances of the task being rejected.
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