Comments on a Case Study on Engineering Failure Analysis of Link Chain

The article by Tae-Gu Kim et al. conducted elastic FE modeling, which was inappropriate for fracture of elastic-plastic chain material (11.3% of elongation). FE analysis results and the findings in the fractographic analysis did not tally but contradicted each other. The article identified “incorrect installation”/ bending forces as the root cause while FE results of the chain under bending forces showed very low stresses at fracture locations but the highest stress in the middle of shank of the chain. The article's “step-like topographies indicating the fracture due to bending moment rather than uniaxial tension” lacked scientific support. The load value carried by each chain section under bending/incorrect installation was only half of that under tension, thus the article using same load value in FE simulation comparison for bending and tension was incorrect. The real cause of the chain fracture was likely improper checking the lifted load or/and using the wrong chain with much lower safety working load.

Monte Carlo study of SPECT in boron neutron capture therapy for a heterogeneous human phantom

Background: Boron neutron capture therapy [BNCT] is a binary radiotherapy combining biochemical targeting with neutron irradiation. However, monitoring the boron distribution is a fundamental problem in BNCT. Prompt gamma rays emitted by boron capture reaction can be used to address the issue

Materials and Methods: The general-purpose Monte Carlo toolkits Geant4 and MCNP were used for the simulations. A cubic phantom with soft tissue was used to study the prompt gamma emission during BNCT. The Chinese hybrid phantom with arbitrary tumors was constructed and used to acquire the 0.478 MeV prompt gamma rays in BNCT. Tomographic images were reconstructed with the maximum likelihood expectation maximization [MLEM] algorithm

Results: Comparison between MCNP and Geant4 showed a similar gamma rays emission rate in soft tissue. Up to 30 gamma ray peaks were found in the simulation, and 0.478 MeV prompt gamma ray from boron was clearly observed. The single brain tumor with variable diameter from 1 cm to 4 cm in the heterogeneous anthropomorphic phantom was each time found to be recognizable in the reconstructed image. Furthermore, in a patient with four tumors, the variable distance between the source and the tumors leads to a neutron attenuation thus resulting in an inhomogeneous number of prompt gammas

Conclusion: The SPECT system for a heterogeneous phantom in BNCT was simulated with Geant4. The results show that BNCT-SPECT is valid for the reconstruction of the boron capture interaction position for a heterogeneous patient

Impacts of multiple-field irradiation and boron concentration on the treatment of boron neutron capture therapy for non-small cell lung cancer

Background: Boron neutron capture therapy [BNCT] is a radiotherapy that combines biological targeting and high linear energy transfer. A potential therapeutic approach for non-small cell lung cancer [NSCLC] is considered. However, dose in lung tumor is not homogeneous, and it will reduce the effect of BNCT treatment. In order to improve the dose distribution of BNCT, the multi-field irradiation strategy and its effects need to be explored

Materials and Methods: Common NSCLC model was defined in Chinese hybrid reference phantom and the boron concentration in skin and tumor varied from 6 to 18 ppm and from 30 to 65 ppm, respectively. Monte Carlo method for dose distribution calculation was used. Accelerator-based neutron source called [Neuboron source] was used and multi-field source irradiation plans were designed to optimize the dose distribution

Results: Under one-field irradiation, it was not feasible to perform BNCT, because the skin dose is unlikely to meet its dose limit. Under two- and three-field irradiation, the uniformity of tumor dose was improved and the maximum dose to organs at risk [OARs] decreased. If boron concentration in skin was between 6-18 ppm, BNCT was feasible with the boron concentration in tumor reaching about 57-60 ppm for two-field irradiation and 41-45 ppm for three-field irradiation, respectively

Conclusion: The multi-field irradiation plan could improve the dose distribution and the feasibility of BNCT for NSCLC. Theoretical distributions of Boron-10 were obtained to meet the treatable requirement of BNCT, which could provide a reference for NSCLC using BNCT in future multiple-field irradiation

Multiple transcripts of anoctamin genes expressed in the mouse submandibular salivary gland

PURPOSE: Salivary fluid formation is primarily driven by Ca2+-activated, apical efflux of chloride into the lumen of the salivary acinus. The anoctamin1 protein is an anion channel with properties resembling the endogenous calcium-activated chloride channels. In order to better understand the role of anoctamin proteins in salivary exocrine secretion, the expression of the ten members of the anoctamin gene family in the mouse submandibular gland was studied. METHODS: Total RNA extracted from mouse submandibular salivary glands was reverse transcribed using primer pairs to amplify the full-length coding regions of each anoctamin gene and was subcloned into plasmid vectors for DNA sequencing. Alternative splice variants were also screened by polymerase chain reaction using primer pairs that amplified six overlapping regions of the complementary DNA of each anoctamin gene, spanning multiple exons. RESULTS: Multiple anoctamin transcripts were found in the mouse submandibular salivary gland, including full-length transcripts of anoctamin1, anoctamin3, anoctamin4, anoctamin5, anoctamin6, anoctamin9, and anoctamin10. Exon-skipping splicing in the N-terminal exons of the anoctamins1, anoctamin5, and anoctamin6 genes resulted in multiple alternative splice variants. No expression of anoctamin2, anoctamin7, or anoctamin8 was found. CONCLUSIONS: The predominant anoctamin transcript expressed in the mouse submandibular gland is anoctamin1ac. The chloride channel protein produced by anoctamin1ac is likely responsible for the Ca2+-activated chloride efflux, which is the rate-limiting step in salivary exocrine secretion.

Leak marking scheme for construction quality testing of geomembrane liners in landfills

Landfill is the major method of solid waste disposal in developing countries. To protect soil and groundwater from contamination, anti-seepage systems have to be installed in landfills. However, during the construction of anti-seepage system, many factors can result in holes in geomembrane liners. For the purpose of improving construction quality, the construction company needs to find the leaks in geomembrane liners and analyze the damage causes according to the positions after construction. The electrical method can effectively test the integrity of geomembrane liners. In this paper, we combine the electrical method with the wireless location technology and bring forth a leak marking scheme. The working flow of the scheme is as follows: place two acoustic transceivers on two vertexes s of the detection area; after detecting the leaks with the electrical method, calculate the leaks' relative coordinates in the detection area through acoustic ranging and, then, mark positions of leaks in the landfill. At last, we design acoustic signals for ranging, analyze their performance on anti-interference, and design the leak marking algorithm

Are there risks in the long term outcome of children born following assisted reproduction technology?

Most studies of assisted reproduction technologies reported that congenital malformations and aberrations, childhood cancers, acquired medical conditions, chronic illness, physical growth, and cognitive and socioemotional development were within the expected range for naturally conceived pregnancies. However, few studies had included children beyond adolescence, and many unanswered questions remain about their long-term outcomes. To optimise outcome, the endpoint one aims to achieve should be BESST outcome [Birth Emphasising a Successful Singleton at Term]. A multiple preterm birth is the main factor that adversely affects the outcome of children conceived by assisted reproduction technologies

Risks in multiple births especially from twin twin transfusion syndrome

Multiple pregnancies have increased over time, and currently account for 10% of perinatal deaths. Compared to singleton births, the perinatal mortality rate is four times higher and the cerebral palsy rate is five times higher in twins. Monozygotic monochorionic twins are at the highest risk, due firstly to the cell division process leading to chromosomal or other anomalous lethal aberration in one fetus, and secondly to twin twin transfusion syndrome [TTTS] especially from its adverse consequences on the surviving fetus if there is fetal death of its co-twin. The incidence of TTTS is 20% in monozygotic monochorionic twins. Although perinatal mortality in TTTS has reduced from 80% to 40%, neonatal and paediatric morbidity remains high. Ultrasonographic studies showed cardiac dysfunction in 80% and brain lesions in over 50% of cases. Serious ischaemic and embolic complications can also occur in the gut, liver, kidneys and limbs. Cerebral palsy develops in 20% of TTTS survivors, especially if the co-twin dies in utero, with another 20% having minor neurodevelopmental disabilities. Data are emerging on the obstetric risks, survival and neurological outcome associated with interventions for treating TTTS. R and omised controlled trials to examine the benefits and risks of these strategies and a TTTS registry at a national or an international level are recommended to help improve management and audit perinatal and paediatric outcomes

Parentage testing anomalies in Hong Kong SAR of China / 中华医学杂志(英文版)

<p><b>OBJECTIVE</b>To determine if there are any differences in the number of exclusions from paternity of men using an anonymous parentage testing service compared with that of men using an in-person parentage testing service provided by the same company in Hong Kong SAR of China.</p><p><b>METHODS</b>Comparable numbers of consecutive anonymous and in-person parentage tests conducted by the same company were analyzed.</p><p><b>RESULTS</b>Men using an anonymous parentage testing service were excluded from paternity at a significantly greater rate (P < 0.001), compared with men using an in-person parentage test service.</p><p><b>CONCLUSIONS</b>The results obtained from anonymous parentage testing indicate that the number of families containing children of doubtful parentage is much greater than expected previously. As illegitimate children are known to suffer greater degrees of abuse and neglect, this finding poses serious social questions regarding the welfare of families, which the relevant authorities should acknowledge and address.</p>