Detailed evaluation of Mobius3D dose calculation accuracy for volumetric-modulated arc therapy

PurposeTo perform a detailed evaluation of dose calculation accuracy and clinical feasibility of Mobius3D. Of particular importance, multileaf collimator (MLC) modeling accuracy in the Mobius3D dose calculation algorithm was investigated.MethodsMobius3D was fully commissioned by following the vendor-suggested procedures, including dosimetric leaf gap (DLG) optimization. The DLG optimization determined an optimal DLG correction factor which minimized the average difference between calculated and measured doses for 13 patient volumetric-modulated arc therapy (VMAT) plans. Two sets of step-and-shoot plans were created to examine MLC and off-axis open fields modeling accuracy of the Mobius3D dose calculation algorithm: MLC test set and off-axis open field test set. The test plans were delivered to MapCHECK for the MLC tests and an ionization chamber for the off-axis open field test, and these measured doses were compared to Mobius3D-calculated doses.ResultsThe mean difference between the calculated and measured doses across the 13 VMAT plans was 0.6% with an optimal DLG correction factor of 1.0. The mean percentage of pixels passing gamma from a 3%/1 mm gamma analysis for the MLC test set was 43.5% across the MLC tests. For the off-axis open field tests, the Mobius3D-calculated dose for 1.5 cm square field was −4.6% lower than the chamber-measured dose.ConclusionsIt was demonstrated that Mobius3D has dose calculation uncertainties for small fields and MLC tongue-and-groove design is not adequately taken into consideration in Mobius3D. Careful consideration of DLG correction factor, which affects the resulting dose distributions, is required when commissioning Mobius3D for patient-specific QA.     

Could the glycosylation analysis of seminal plasma clusterin become a novel male infertility biomarker?

Male infertility is becoming a rapidly growing problem around the world, mainly in the highly developed countries. Seminal proteome composition seems to be one of the crucial factors of the proper course of fertilization ‐ clusterin (CLU) is among the most important ones. CLU, as one of the crucial seminal plasma glycoproteins, plays a very important role in sperm capacitation and immune tolerance in the female reproductive tract. CLU is also known as a sensitive marker of oxidative stress. It has six n ‐glycosylation sites and also exhibits chaperone activity. An analysis of changes in the profile and degree of CLU glycosylation may shed some new light on the molecular mechanisms of the fertilization process and may be used as an additional diagnostic marker of male fertility. This study constitutes a review of the recently available literature concerning human seminal CLU, including changes in its glycosylation, analyzed in the context of human reproduction.     

International principles and standards for native seeds in ecological restoration

The growing demand for native seeds in ecological restoration and rehabilitation, whether for mining, forest, or ecosystem restoration, has resulted in a major global industry in the sourcing, supply, and sale of native seeds. However, there are no international guidance documents for ensuring that native seeds have the same standards of quality assurance that are regular practice in the crop and horticultural industries. Using the International Principles and Standards for the Practice of Ecological Restoration as a foundation document, we provide for the first time a synthesis of general practices in the native seed supply chain to derive the Principles and Standards for Native Seeds in Ecological Restoration (“Standards”). These practices and the underpinning science provide the basis for developing quality measures and guidance statements that are adaptable at the local, biome, or national scale. Importantly, these Standards define what is considered native seed in ecological restoration and highlight the differences between native seeds versus seeds of improved genetics. Seed testing approaches are provided within a logical framework that outline the many different dormancy states in native seed that can confound restoration outcomes. A “pro‐forma” template for a production label is included as a practical tool that can be customized for local needs and to standardize reporting to end‐users on the level of seed quality and germinability to be expected in a native seed batch. These Standards are not intended to be mandatory; however, the guidance statements provide the foundation upon which regulatory approaches can be developed by constituencies and jurisdictions.     

Dormancy and germination: making every seed count in restoration

From 50 to 90% of wild plant species worldwide produce seeds that are dormant upon maturity, with specific dormancy traits driven by species' occurrence geography, growth form, and genetic factors. While dormancy is a beneficial adaptation for intact natural systems, it can limit plant recruitment in restoration scenarios because seeds may take several seasons to lose dormancy and consequently show low or erratic germination. During this time, seed predation, weed competition, soil erosion, and seed viability loss can lead to plant re‐establishment failure. Understanding and considering seed dormancy and germination traits in restoration planning are thus critical to ensuring effective seed management and seed use efficiency. There are five known dormancy classes (physiological, physical, combinational, morphological, and morphophysiological), each requiring specific cues to alleviate dormancy and enable germination. The dormancy status of a seed can be determined through a series of simple steps that account for initial seed quality and assess germination across a range of environmental conditions. In this article, we outline the steps of the dormancy classification process and the various corresponding methodologies for ex situ dormancy alleviation. We also highlight the importance of record‐keeping and reporting of seed accession information (e.g. geographic coordinates of the seed collection location, cleaning and quality information, storage conditions, and dormancy testing data) to ensure that these factors are adequately considered in restoration planning.     

Changes in soil properties and resistance to concentrated flow across a 25‐year passive restoration chronosequence of grasslands on the Chinese Loess Plateau

Revegetation represents an effective measure for preventing soil erosion on the Loess Plateau. However, the effects of revegetation‐induced changes in soil and root properties on soil resistance to concentrated flow erosion (SRC) remain unclear. This study sampled soils and roots across a 25‐year chronosequence from farmland to grasslands of different ages (3, 7, 10, 18, and 25 years) to quantify variations in soil and root properties (soil bulk density, SBD; soil disintegration rate, SDR; saturated hydraulic conductivity, SHC; organic matter content, OMC; water‐stable aggregate, WSA; mean weight diameter, MWD; root mass density, RMD; root length density, RLD; and root surface area density, RSAD) and their effects on SRC. Farmland and grassland SRCs were obtained using a hydraulic flume. Soil properties and root density gradually improved with restoration time. In terms of the comprehensive soil property index calculated via principal component analysis, grassland values were 0.66 to 1.94 times greater than farmland values. Grassland SRCs increased and gradually stabilized (>18 years) over time and were 1.60 to 8.26 times greater than farmland SRC. SRC improvement was significantly related to increases in OMC, SHC, WSA, and MWD and decreases in SBD and SDR over time. SRC was effectively simulated by the Hill curve of RMD, RLD, and RSAD. SDR, SHC, and RMD (0.5–1.0 mm) affected SRC the most. This study scientifically describes how revegetation improves soil quality and soil resistance to flow erosion, and suggests that vegetations rich in 0.5–1.0 mm roots should be preferred during revegetation.     

西番莲采后品质劣变及贮藏保鲜技术研究进展

西番莲(Passiflora caerulea)是一种营养丰富的热带亚热带特色水果,采后易发生果实品质劣变现象,是制约采后西番莲果实保鲜期的重要因素。本文就西番莲采后果实褶皱及失重、果皮色泽变化、营养物质含量减少和采后病害发生等品质劣变机理,及其低温、热处理、包装、1-MCP、多糖和化学保鲜剂等西番莲果实采后保鲜技术的国内外相关研究进行综述,以期为维持西番莲果实贮藏品质、延长果实保鲜期提供指导。     

Statistical and multivariate statistical techniques to trace the sources and affecting factors of groundwater pollution in a rapidly growing city on the Chinese Loess Plateau

Abstract

Groundwater quality is defined by various water quality parameters. The aims of the research are to understand the relationships among different groundwater quality parameters and to trace the sources and affecting factors of groundwater pollution via statistical and multivariate statistical techniques. The 36 shallow groundwater samples collected from shallow pumping wells in Yan’an City were analyzed for various water quality parameters. Correlation analysis, principal component analysis (PCA), hierarchical cluster analysis (HCA), and multivariable linear regressions (MLR) were jointly used in this study to explore the sources and affecting factors of groundwater pollution. The study reveals that the mineral dissolution/precipitation and anthropogenic input are the main sources of the physicochemical indices and trace elements in the groundwater. Groundwater chemistry is predominantly regulated by natural processes such as dissolution of carbonates, silicates, and evaporates and soil leaching, followed by human activities as the second factor. Climatic factors and land use types are also important in affecting groundwater chemistry. Cl^– is the greatest contributor to the overall groundwater quality revealed by the two regression models. The first model which has eight dependent variables is high in model reliability and stability, and is recommended for the overall groundwater quality prediction. The study is helpful for understanding groundwater quality variation in urban areas.     

Traits mediate drought effects on wood carbon fluxes

CO₂ fluxes from wood decomposition represent an important source of carbon from forest ecosystems to the atmosphere, which are determined by both wood traits and climate influencing the metabolic rates of decomposers. Previous studies have quantified the effects of moisture and temperature on wood decomposition, but these effects were not separated from the potential influence of wood traits. Indeed, it is not well understood how traits and climate interact to influence wood CO₂ fluxes. Here, we examined the responses of CO₂ fluxes from dead wood with different traits (angiosperm and gymnosperm) to 0%, 35%, and 70% rainfall reduction across seasonal temperature gradients. Our results showed that drought significantly decreased wood CO₂ fluxes, but its effects varied with both taxonomical group and drought intensity. Drought‐induced reduction in wood CO₂ fluxes was larger in angiosperms than gymnosperms for the 35% rainfall reduction treatment, but there was no significant difference between these groups for the 70% reduction treatment. This is because wood nitrogen density and carbon quality were significantly higher in angiosperms than gymnosperms, yielding a higher moisture sensitivity of wood decomposition. These findings were demonstrated by a significant positive interaction effect between wood nitrogen and moisture on CO₂ fluxes in a structural equation model. Additionally, we ascertained that a constant temperature sensitivity of CO₂ fluxes was independent of wood traits and consistent with previous estimates for extracellular enzyme kinetics. Our results highlight the key role of wood traits in regulating drought responses of wood carbon fluxes. Given that both climate and forest management might extensively modify taxonomic compositions in the future, it is critical for carbon cycle models to account for such interactions between wood traits and climate in driving dynamics of wood decomposition.     

Spatial modeling of techno‐economic potential of biojet fuel production in Brazil

It is expected that Brazil could play an important role in biojet fuel (BJF) production in the future due to the long experience in biofuel production and the good agro‐ecological conditions. However, it is difficult to quantify the techno‐economic potential of BJF because of the high spatiotemporal variability of available land, biomass yield, and infrastructure as well as the technological developments in BJF production pathways. The objective of this research is to assess the recent and future techno‐economic potential of BJF production in Brazil and to identify location‐specific optimal combinations of biomass crops and technological conversion pathways. In total, 13 production routes (supply chains) are assessed through the combination of various biomass crops and BJF technologies. We consider temporal land use data to identify potential land availability for biomass production. With the spatial distribution of the land availability and potential yield of biomass crops, biomass production potential and costs are calculated. The BJF production cost is calculated by taking into account the development in the technological pathways and in plant scales. We estimate the techno‐economic potential by determining the minimum BJF total costs and comparing this with the range of fossil jet fuel prices. The techno‐economic potential of BJF production ranges from 0 to 6.4 EJ in 2015 and between 1.2 and 7.8 EJ in 2030, depending on the reference fossil jet fuel price, which varies from 19 to 65 US$/GJ across the airports. The techno‐economic potential consists of a diverse set of production routes. The Northeast and Southeast region of Brazil present the highest potentials with several viable production routes, whereas the remaining regions only have a few promising production routes. The maximum techno‐economic potential of BJF in Brazil could meet almost half of the projected global jet fuel demand toward 2030.     

Anthropogenic noise reduces avian feeding efficiency and increases vigilance along an urban–rural gradient regardless of species’ tolerances to urbanisation

Anthropogenic noise can adversely impact urban bird populations by interfering with vocal communication. Less research has addressed if anthropogenic noise masks the adventitious sounds that birds use to aid predator detection, which may lead to increased vigilance and reduced feeding efficiency. We test this hypothesis using a controlled playback experiment along an urban–rural gradient in Sheffield (UK). We also test the related predictions that anthropogenic noise has the greatest impacts on vigilance and feeding efficiency in rural populations, and on species that are more sensitive to urbanisation. We focus on six passerines, in order from most to least urbanised (based on how urbanisation influences population densities): blue tit Cyanistes caeruleus, robin Erithacus rubeculla, great tit Parus major, chaffinch Fringilla coelebs, coal tit Periparus ater and nuthatch Sitta europaea. We used play-back of anthropogenic urban noise and a control treatment at 46 feeding stations located along the urban–rural gradient. We assess impacts on willingness to visit feeders, feeding and vigilance rates. Exposure to anthropogenic noise reduced visit rates to supplementary feeding stations, reduced feeding rates and increased vigilance. Birds at more urban sites exhibit less marked treatment induced reductions in feeding rates, suggesting that urban populations may be partially habituated or adapted to noisy environments. There was no evidence, however, that more urbanised species were less sensitive to the impacts of noise on any response variable. Our results support the adventitious sound masking hypothesis. Urban noise may thus interfere with the ability of birds to detect predators, reducing their willingness to use food rich environments and increase vigilance rates resulting in reduced feeding rates. These adverse impacts may compromise the quality of otherwise suitable foraging habitats in noisy urban areas. They are likely to be widespread as they arise in a range of species including common urban birds.