Verification of methodologies for estimating human exposure to high levels of mercury pollution in the environment

A considerable amount of work has been conducted developing exposure estimate models for quantitative evaluation of Hg intake and human health risks, but few have assessed the applicability and the validity for evaluating the risks posed by Hg in the environment and have achieved very mixed results. The present study focused on verifying the daily Hg intake estimates using exposure estimate models. Deterministic methods and the probabilistic methods (the Monte Carlo) were applied to simulate the daily Hg intake doses which were verified by comparing the estimates to those established from measured Hg concentrations in the hair of 289 participants. The results showed that the single-value deterministic method for simulating Hg exposure levels overestimated the level of risk by a factor of 1.5 when compared with the highest concentration of the Hg observed in the hair of the study population. The average daily Hg intake doses simulated using the probabilistic simulation were similar in distribution to the biomarker data, with the variability of 23%. The difference between the probabilistic simulation and the data derived from hair Hg levels was considered to be most likely due to the uncertainties in unconfirmed questionnaire-based survey data, small sampling sizes and the surrogates used in the exposure models. When the reference dose (RfD) of 0.1 ?g/kg body weight/day was adopted as the acceptable dose for daily intake rate, there were approximately 19% estimated to have potential Hg exposure risks based on the Monte Carlo simulation. This percentage was favourably similar to the 17% determined from Hg concentrations in the hair samples. The findings implied that the existing exposure models together with the probabilistic approach were appropriate for the research of human exposure to Hg. On the other hand, low Hg levels in the participants’ hair indicated that Hg accumulated in the study population was not very serious, probably due to the good Hg absorptivity of the on-site fly ash. However, it should be advised that consumption of river fish elevates the health risks to the local population

The Multi-shadow Analysis of LED Secondary Optics

AbstractDue to these advantages, small size, low heat radiation, long life time, and high luminous efficiency, the light-emitting diodes (LEDs) have been used widely to the varied lighting in recent years. However, the LEDs have the higher intensity of light in central region and the scattering in the surrounding during lighting, so it is necessary to modify the LED projection by the secondary optical lens. The extra secondary optical lens can enhance the light collection efficiency of LED, but it will readily induce the multi-shadow phenomenon during lighting, which has a significant impact on the human vision. In this study, the LED illumination module with/without secondary optical lens, total internal reflected (TIR) lens or reflection mirror cup, can be simulated by the Apilux(R) optical software. The result indicates that the approach can identify the level of multi-shadow images according to the deviations in light intensity, and will be new performance criteria of LEDs for users

Growth Hormone Deficiency in a Case of Crouzon Syndrome with Hydrocephalus

Crouzon syndrome is one of the most common craniofacial syndromes and is inherited as autosomal dominant with variable expression. We report an 11 and a half-year-old boy with Crouzon syndrome with severe growth retardation. He had hydrocephalus since infancy and recently suffered from frequent dizziness. His bone age was only 5 years according to the Greulich and Pyle atlas. Magnetic resonance imaging showed shallow orbits, obstructive hydrocephalus, and cerebellar tonsil herniation. Growth hormone provocative tests revealed a reduced peak growth hormone response in both insulin and clonidine tests. Severe iron deficiency anemia was noted at the same time. Molecular analysis identified a common mutation point of Cys278Phe for Crouzon syndrome in exon IIIa of the fibroblast growth factor receptor 2 (FGFR2) gene. Since growth retardation is not a common feature of Crouzon syndrome, we reviewed the literature for the incidence of hydrocephalus in Crouzon syndrome and the association with growth hormone deficiency

Identifying the attack sources of botnets for a renewable energy management system by using a revised locust swarm optimisation scheme

Distributed denial of service (DDoS) attacks often use botnets to generate a high volume of packets and adopt controlled zombies for flooding a victim’s network over the Internet. Analysing the multiple sources of DDoS attacks typically involves reconstructing attack paths between the victim and attackers by using Internet protocol traceback (IPTBK) schemes. In general, traditional route-searching algorithms, such as particle swarm optimisation (PSO), have a high convergence speed for IPTBK, but easily fall into the local optima. This paper proposes an IPTBK analysis scheme for multimodal optimisation problems by applying a revised locust swarm optimisation (LSO) algorithm to the reconstructed attack path in order to identify the most probable attack paths. For evaluating the effectiveness of the DDoS control centres, networks with a topology size of 32 and 64 nodes were simulated using the ns-3 tool. The average accuracy of the LS-PSO algorithm reached 97.06 for the effects of dynamic traffic in two experimental networks (number of nodes = 32 and 64). Compared with traditional PSO algorithms, the revised LSO algorithm exhibited a superior searching performance in multimodal optimisation problems and increased the accuracy in traceability analysis for IPTBK problems

TPMD: a database and resources of microsatellite marker genotyped in Taiwanese populations

Taiwan Polymorphic Marker Database (TPMD) (http://tpmd.nhri.org.tw/) is a marker database designed to provide experimental details and useful marker information allelotyped in Taiwanese populations accompanied by resources and technical supports. The current version deposited more than 372 000 allelotyping data from 1425 frequently used and fluorescent-labeled microsatellite markers with variation types of dinucleotide, trinucleotide and tetranucleotide. TPMD contains text and map displays with searchable and retrievable options for marker names, chromosomal location in various human genome maps and marker heterozygosity in populations of Taiwanese, Japanese and Caucasian. The integration of marker information in map display is useful for the selection of high heterozygosity and commonly used microsatellite markers to refine mapping of diseases locus followed by identification of disease gene by positional candidate cloning. In addition, our results indicated that the number of markers with heterozygosity over 0.7 in Asian populations is lower than that in Caucasian. To increase accuracy and facilitate genetic studies using microsatellite markers, we also list markers with genotyping difficulty due to ambiguity of allele calling and recommend an optimal set of microsatellite markers for genotyping in Taiwanese, and possible extension of genotyping in other Mongoloid populations