Geometric and dosimetric accuracy of dynamic tumor tracking during volumetric-modulated arc therapy using a gimbal mounted linac

Publication date: Available online 11 November 2017
Source:Radiotherapy and Oncology
Author(s): Tomohiro Ono, Yuki Miyabe, Kunio Takahashi, Mami Akimoto, Nobutaka Mukumoto, Yoshitomo Ishihara, Mitsuhiro Nakamura, Takashi Mizowaki, Masahiro Hiraoka
PurposeThe aim was to examine the feasibility of a dynamic tumor-tracking volumetric modulated arc therapy (DTT-VMAT) technique using a gimbal-mounted linac and assess its positional, mechanical and dosimetric accuracy.Materials and methodsDTT-VMAT was performed using a surrogated signal-based technique. The positional tracking accuracy was evaluated as the difference between the predicted and detected target positions for various wave patterns. Mechanical accuracy measurements included gantry, multileaf collimator (MLC) and gimbal positions. The differences between the command and the measured positions were evaluated for various wave patterns. Dosimetric verification was performed using Gafchromic EBT3 films in the benchmark phantom and two clinical cases.ResultsThe root mean square error (RMSE) of the positional accuracy was within 0.31 mm. The RMSE of mechanical accuracy was within 0.14° for the gantry, 0.11 ± 0.02 mm for the MLC and 0.13 mm for the gimbal positions. The passing rate of the 3%/3 mm gamma index was greater than 83.3% and 91.2% for the benchmark phantom and two clinical cases, respectively.ConclusionsThe positional, mechanical and dosimetric accuracy of DTT-VMAT were evaluated. DTT-VMAT with a gimbal-mounted linac had sufficient accuracy and presents a new strategy for treatment of several tumors with respiratory motion.



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Industry interests in gambling research: Lessons learned from other forms of hazardous consumption

Publication date: March 2018
Source:Addictive Behaviors, Volume 78
Author(s): S. Cowlishaw, S.L. Thomas
Research indicates that the evidential bases for many harm reduction policies targeting hazardous consumptions (including tobacco, alcohol and gambling) have been distorted by commercial industries that derive revenue from such commodities. These distortions are best illustrated by research on tobacco and alcohol, which indicates similar tactics used by industries to determine favourable policy environments through engineering of evidence, among other approaches. Although there is concern that gambling research is similarly vulnerable to commercial interests, the relevant literature lags far behind other fields and the aim of this paper is to increase familiarity with tactics used by industries for influencing research. It summarises the conceptual and empirical bases for expecting conflicts between goals of public health and companies that profit from hazardous consumptions. It also summarises evidence describing practices deployed by tobacco corporations, which include third-party techniques and the selective funding of research to manufacture doubt and deflect attention away from the consequences of smoking. It then reviews both early and emerging evidence indicating similar strategies used by alcohol industry, and uses this literature to view practices of the gambling industry. It argues that parallels regarding selective funding of research and third-party techniques provide grounds for strong concern about commercial influences on gambling research, and implementation of precautionary approaches to management of vested interests.



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To create or to recall original ideas: Brain processes associated with the imagination of novel object uses

Publication date: Available online 11 November 2017
Source:Cortex
Author(s): Mathias Benedek, Till Schües, Roger E. Beaty, Emanuel Jauk, Karl Koschutnig, Andreas Fink, Aljoscha C. Neubauer
This fMRI study investigated what brain processes contribute to the generation of new ideas. Brain activation was measured while participants generated new original object uses, recalled original object uses, or recalled common object uses. Post-scan evaluations were used to confirm what ideas were newly generated on the spot or actually retrieved from memory. When compared to the recall of common ideas, the generation of new and old original ideas showed a similar activation pattern including activation of bilateral parahippocampal and mPFC regions, suggesting that the construction of new ideas builds on similar processes like the reconstruction of original ideas from episodic memory. As a difference, the generation of new object uses involved higher activation of a focused cluster in the left supramarginal gyrus compared to the recall of original ideas. This finding adds to the converging evidence that the left supramarginal gyrus is crucially involved in the construction of novel representations, potentially by integrating memory content in new ways and supporting executively demanding mental simulations. This study deepens our understanding of how creative thought builds on and goes beyond memory.



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Human laterality for manipulation and gestural communication related to 60 everyday activities: impact of multiple individual-related factors

Publication date: Available online 11 November 2017
Source:Cortex
Author(s): Jacques Prieur, Stéphanie Barbu, Catherine Blois-Heulin
Literature on laterality emphasises the importance of implementing a comprehensive investigation of humans' and non-humans' laterality for both non-communication and communication functions. Adopting a global approach should enhance our understanding of the mechanistic drivers of human brain functional lateralisation and help to explore further the nature of the left-hemispheric systems for both functions. This study investigated human laterality for both functions by taking, for the first time, numerous behaviours and multiple potential influential factors into consideration. We analysed replies to the Rennes Laterality Questionnaire that takes into account simultaneously: participants' behavioural, demographic and social characteristics as well as their genetic/social learning components and collateral factors such as health problems. We collected and analysed a large data set including 450,220 item responses (317,594 items related to behavioural laterality and 132,626 items related to personal information) by 5,904 participants. The majority of participants were right-lateralised for nine behavioural categories. The laterality of right-lateralised individuals for the behaviours considered varied very little between behavioural categories, contrary to the laterality of ambiguously- and left-lateralised individuals. This is the first evidence of the stability of right-lateralised individuals and the relative flexibility of ambiguously- and left-lateralised individuals with regards to behavioural laterality related to 60 everyday activities. Moreover, the laterality patterns of our study population were linked in particular to the following individual-related factors: demographic characteristics (current continent of residence), social characteristics (socio-professional group and study level), and collateral factors (writing hand, forced right-hand use, guiding eye, and health problems related to ear and back). We discuss our findings in relation to the evolutionary roots of human brain lateralisation for non-communication and communication functions.



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A 3D supramolecular network as highly selective and sensitive luminescent sensor for PO43− and Cu2+ ions in aqueous media

Publication date: March 2018
Source:Dyes and Pigments, Volume 150
Author(s): Yuan Xie, Shigang Ning, Yong Zhang, Zilong Tang, Shaowei Zhang, Ruiren Tang
A 2D coordination polymer, {[Zn(btca)(py)2]}n (1), (H2btca = benzotriazole-5-carboxylic acid, py = pyridine), has been prepared with high yield by the hydrothermal reaction of H2btca and Zn(NO3)2·6H2O in the presence of py, which has been further characterized by kinds of methods combining elemental analysis, thermogravimetric (TG) analysis, infrared (IR) spectrum, powder X-ray diffraction (PXRD), and X-ray single-crystal diffraction. In 1, each Zn²⁺ adopts a five-coordinated pentagonal bipyramid geometry with one O atom from one carboxylate group of btca²⁻ ligand and four N atoms from two btca²⁻ ligands and two py molecules. Adjacent Zn²⁺ are connected by btca²⁻ ligands to generate a 2D layer with the 'fes'-type topology, which could further form a 3D supramolecular network through hydrogen bonds interactions. Furthermore, the luminescent results reveal that the detection limit of 1 as a luminescent sensor to probe Cu²⁺ and PO4³⁻ could reach 3 and 45 ppm, respectively, suggesting that 1 can sensitively and selectively detect Cu²⁺ and PO4³⁻ in aqueous solution.

Graphical abstract

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In vivo assessment of polydatin, a natural polyphenol compound, on arsenic-induced free radical overproduction, gene expression, and genotoxicity

Abstract

Arsenic (As) is a well-known contaminant of global groundwater. Its exposure causes several hazardous effects on animals and human via oxidative stress. The present study examined the effect of polydatin (PD) on free radical overproduction in rats exposed to As. Thirty-five male rats randomly allocated into five equal groups. To the control group, physiological saline was given orally and to the second group only 100 mg/L As was given by drinking water for 60 days. The other groups were treated with As (100 mg/L) and PD orally at 50, 100, and 200 mg/kg/day, respectively. Treatment with As enhanced malondialdehyde level but decreased glutathione level in blood, liver, kidney, brain, lung, and heart of rats. Also, As decreased superoxide dismutase and catalase activities of erythrocyte, liver, kidney, brain, lung, and heart in rats. Furthermore, As treatment gave rise to increased DNA damage and gene expressions of interleukin 1 beta (IL-1β), nuclear factor kappa beta (NFκB), p53, and tumor necrosis factor-α (TNF-α) in the lung, brain, kidney, and liver. However, treatment of PD ameliorated As-exposed lipid peroxidation, antioxidant enzymes activities, DNA damage, gene expressions, and histopathological changes in tissues. In conclusion, PD has a dose-dependent protective effect on lipid peroxidation and antioxidant defense mechanism in rats against As exposure.

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Heavy metal distribution in Tiaoxi River’s sediment

Abstract

According to current study, seven surface sediments and three sediment cores were collected from three typical areas of Tiaoxi River, which were living area, agricultural area, and industrial area. The water quantity into the Lake Taihu from the Tiaoxi River accounted for almost one third of the total water quantity by all rivers into the Lake Taihu. To study geochemical features and pollution history of heavy metals in three typical areas of Tiaoxi River, total content and chemical fractionations of Cu, Pb, Cd, Cr, Mn, Zn, Fe, As, and Hg were analyzed for surface and core sediments using the speciation extraction procedure, proposed by the Commission of the European Communities Bureau of Reference (BCR), together with grain size and organic carbon measurements. The results showed that the concentration of nine heavy metals and the variation characteristics of Zn, Cu, Fe, Mn, and Cr are different among five cores, which has shown that the river responses to natural and anthropogenic activities were dissimilar in various areas. BCR sequential extraction showed contents of Cr, Fe, and Cu were dominated in the remaining parts. Non-residual fractions for Zn and Mn contained major portions. Based on RAC (risk assessment core), the risk of Mn was high to very high in the three typical areas, and the risk of Zn was medium in the three typical areas.

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