Possibility of X-ray spectral diagnostics of a plasma in the tracks of fast multicharged ions

A plasma model of the relaxation of a medium within the tracks of heavy ions in condensed matter is proposed that is based on solving time-dependent radiative collisional kinetic equations with the initial condition corresponding to a medium’s state described by the classical model of multiple ionization of the target atoms by the field of fast multicharged ions. It is shown that the plasma model allows one to describe X-ray spectra recorded in the interaction of ion beams with condensed targets. An X-ray spectral method for plasma diagnostics is proposed that is based on the plasma model. The results obtained can also be used to study the initial stage of the formation of defects in solid bodies under the action of individual fast heavy ions.     

Microfiltration of gluten processing streams from corn wet milling

In corn wet milling, dry matter can be separated from liquids in process streams with centrifuges or vacuum belt filtration (VBF). Because separations usually are not complete, dry matter can be lost in the liquid streams (overflow from the gluten thickener centrifuge and filtrate from VBF). This represents a loss of nutrients, especially protein, to low valued coproducts and reduces quality of water for recycling within the process. The objective was to compare microfiltration of light and heavy gluten process streams to conventional separation methods. Batches of light and heavy gluten were obtained from a wet mill plant and processed by microfiltration. Samples of permeate and concentrate from microfiltration were analyzed and compared to corresponding streams from wet milling. Microfiltration of light gluten resulted in concentrate and permeate streams similar in composition to conventionally processed light gluten using a centrifuge, suggesting that microfiltration is as effective as centrifugation in partitioning solids and water in light gluten. Dewatering of heavy gluten found that conventional VBF caused dry matter concentrations in gluten cake to be higher than concentrate from microfiltration. Permeate from microfiltration of heavy gluten had higher concentrations of ash and lower soluble nitrogen than filtrate from VBF. Microfiltration was able to remove more ash from concentrate, which may improve the value of wet milling coproducts. These data demonstrated microfiltration has potential for separation of light and heavy gluten streams, but more data are needed on effectiveness and practicality.     

Distribution of planktonic crustaceans in Lake Balkhash in relation to environmental factors

The quantitative development of planktonic crustaceans in Lake Balkhash has been studied in relation to water transparency, pH, mineralization, ion concentrations, ion ratios, content of easily oxidizable organic matter, nutrients, and heavy metals. It is shown that the decrease in the abundance of animals in a brackish part of the lake area is caused by a high concentration of K⁺ at a relatively low amount of Ca²⁺ and Na⁺ ions. The dependence of quantitative development of planktonic crustaceans on the content of nutrients, mineralization, concentrations of the main ions (except for alkali metals) and their ratio is not manifested for all species. Pollution of the lake by heavy metals has caused either a sharp decrease or an increase in the range of variations of the abundance of crustaceans.     

Heavy ion effects in non-biological matter

The effects of swift heavy ions in non-biological matter have been extensively studied during the last few years. Some results on non-biological solids are summarised here which might help to analyse comparatively the effects of high linear energy transfer (LET) particles in biological and non-biological matter. Special emphasis is put on the effects recently observed in organic solids. The experimental study of high-LET effects involves the use of accelerators and irradiation facilities. However, the requirements differ markedly from one study to the next, and ion accelerators of very different types have been used. A synthetic review of the existing sources and facilities is presented.Invited paper presented at the International Symposium on Heavy Ion Research: Space, Radiation Protection and Therapy, Sophia-Antipolis, France, 21–24 March 1994     

Regional grey and white matter changes in heavy male smokers

Cigarette smoking is highly prevalent in the general population but the effects of chronic smoking on brain structures are still unclear. Previous studies have found mixed results regarding regional grey matter abnormalities in smokers. To characterize both grey and white matter changes in heavy male smokers, we investigated 16 heavy smokers and 16 matched healthy controls, using both univariate voxel-based morphometry (VBM) and multivariate pattern classification analysis. Compared with controls, heavy smokers exhibited smaller grey matter volume in cerebellum, as well as larger white matter volume in putamen, anterior and middle cingulate cortex. Further, the spatial patterns of grey matter or white matter both discriminated smokers from controls in these regions as well as in other brain regions. Our findings demonstrated volume abnormalities not only in the grey matter but also in the white matter in heavy male smokers. The multivariate analysis suggests that chronic smoking may be associated with volume alternations in broader brain regions than those identified in VBM analysis. These results may better our understanding of the neurobiological consequence of smoking and inform smoking treatment.     

A track structure model for simulation of strand breaks in plasmid DNA after heavy ion irradiation

We present a track structure model based on the local dose deposited around heavy ion tracks to explain the cross sections for single-strand and double-strand break induction in plasmid DNA in different aqueous buffers. The model is based only on measurable quantities, namely the effect distribution for inducing strand breaks after x-ray irradiation as a function of dose, and the radial dose distribution of the heavy ion track. The effect of indirect DNA damage mediated by free radicals produced in the water surrounding the DNA is accounted for by allowing the radial dose distribution to be smeared in space by an effective target size corresponding to the squared sum of the geometrical extension of the plasmid molecule and the mean free drift path of the radicals in the buffer solution. Our calculations reproduce well the measured cross sections for single-strand and double-strand break induction in SV40 plasmid DNA in various buffer solutions both as a function of the LET and of the specific energy of the heavy ion.     

Initiation-promotion model of tumor prevalence in mice from space radiation exposures

Exposures in space consist of low-level background components from galactic cosmic rays (GCR), occasional intense-energetic solar-particle events, periodic passes through geomagnetic-trapped radiation, and exposure from possible onboard nuclear-propulsion engines. Risk models for astronaut exposure from such diverse components and modalities must be developed to assure adequate protection in future. NASA missions. The low-level background exposures (GCR), including relativistic heavy ions (HZE), will be the ultimate limiting factor for astronaut career exposure. We consider herein a two-mutation, initiation-promotion, radiation-carcinogenesis model in mice in which the initiation stage is represented by a linear kinetics model of cellular repair/misrepair, including the track-structure model for heavy ion action cross-sections. The model is validated by comparison with the harderian gland tumor experiments of Alpen et al. for various ion beams. We apply the initiation-promotion model to exposures from galactic cosmic rays, using models of the cosmic-ray environment and heavy ion transport, and consider the effects of the age of the mice prior to and after the exposure and of the length of time in space on predictions of relative risk. Our results indicate that biophysical models of age-dependent radiation hazard will provide a better understanding of GCR risk than models that rely strictly on estimates of the initial slopes of these radiations.Submitted paper presented at the International Symposium on Heavy Ion Research: Space, Radiation Protection and Therapy, Sophia-Antipolis, France, 21–24 March 1994     

Interaction between water ecosystems and the catchment surface by the example of the Ob’-Irtysh catchment area

The interaction of water basins and watercourses with the catchment surface in the Ob’-Irtysh catchment area is considered. The results of long-term observation of water, suspended matter, and bottom sediments in different segments of the watercourse are summarized and compared. The interaction of major and minor tributaries, natural and artificial water reservoirs with the catchment area is discussed in the context of industrial discharge of heavy metals. The areal distribution of metals along the Ob’ River is heterogeneous. The chemical composition of water in the upper reaches of Ob’ is determined by mercury and complex ore shows; in the middle and lower reaches, by catchments of major tributaries: Tom, Chulym, and, particularly, Irtysh. The Novosibirsk Reservoir purifies the water from coarse suspensions. Wetlands of the catchment enrich the main watercourse in metals and organic matter. Anthropogenic pollution from large cities (Novosibirsk, Tomsk, Surgut, and Nizhnevartovsk) additionally contaminate the watercourse. With abundance of organic matter, heavy metals are accumulated in bottom sediments and, as a consequence, in tissues of predatory fish. The results of long-term studies indicate that oil products and phenols are the main hazard for the middle and lower Ob’ River, especially at elevated water temperatures.     

基于GIS和地统计学的稻田土壤养分与重金属空间变异

以湖南省长沙县北山镇3.56 hm²的水稻田为研究区域,基于网格法(25 m×25 m)等距离取样,采用GIS和地统计学相结合的方法,对研究区土壤耕作层(0～20 cm)的pH值、有机质、全氮、速效磷、阳离子交换量(CEC)与3种典型重金属元素Cd、As、Pb的空间变异特征进行了定量分析.结果表明: 研究区内土壤pH值和Pb含量表现为弱变异,其他各项指标均表现出中等强度变异,变异顺序的大小为:速效磷＞Cd＞全氮＞有机质＞CEC＞As＞Pb＞pH.半方差检验结果表明,有机质、速效磷、As的半方差函数的最佳拟合模型为指数模型;pH、全氮、CEC、Cd和Pb的最佳拟合模型为球状模型;除CEC呈中等空间相关外,其余指标均表现出强烈的空间相关.克里格插值分析表明: pH、全氮、CEC、Pb呈斑块状分布;有机质、速效磷、Cd、As呈块状和带状分布.植被、地形和人类活动是造成研究区土壤养分与重金属格局差异的主要因素.相关性分析表明,部分土壤养分与重金属含量的相关性达到显著水平,其中pH与有机质、Cd与Pb的相关性达到了极显著相关水平.     

Breeding birds from reedbeds to alpine meadows

The main processes that determine the behaviour ofheavy metals in the Scheldt estuary are tidalhydrodynamics, sediment transport, and sorption ofheavy metals on suspended matter. The water qualitymodel WASP is applied to simulate the spatialdistribution of five heavy metals in the estuary,under average hydrodynamic and suspended sedimenttransport regimes. First, the hydrodynamical part ofthe model is constructed and the results are verifiedby comparison with measured water levels and flowvelocities. Secondly, a salt transport model is set upin order to evaluate the hydrodynamical dispersivemixing characteristics. Thirdly, a suspended sedimenttransport model is constructed and finally a transportmodel for heavy metals. The simulated distributions of the sorbedamounts of heavy metals, suspended sediment andsalinity in the estuary agree well with observations.The calculated profiles of dissolved and sorbedconcentrations of heavy metals in the water columnindicate an accumulation of heavy metals in the zoneof the turbidity maximum, while closer to the sea theconcentrations diminish due to mixing of the pollutedfluvial sediments with unpolluted marine sediments andbecause of sediment deposition in the estuary. It canbe concluded that only a small part of the heavymetals reaches the sea. This revised version was published online in July 2006 with corrections to the Cover Date.     

C~(6+)重离子对山黧豆种子的诱变效应

本实验探讨了C~(6+)重离子对山黧豆种子的诱变效应,结果发现,C~(6+)重离子对山黧豆种子的萌发率、成苗率、幼根及幼苗生长速度有着显著的影响,而且辐照剂量与效应呈明显正相关,此外,与~(60)Co-γ射线相比,C~(6+)重离子不仅诱导形成了较高的有丝分裂畸变率,而且还能在所用剂量的低中级剂量范围内(10~2—10~5P/cm~2)产生较宽广的畸变谱,表明C~(6+)重离子照射有可能在辐射损伤较小的情况下产生有用突变。文章还推论了C~(6+)重离子在山黧豆无毒或低毒品系的诱变育种中可能采用的剂量范围。     

离子束生物效应及应用中值得研究的几个问题

重离子束生物效应及重离子束在生命科学中的应用研究,在国内外物理学与生命科学领域中得到了广泛的开展,但对出现的一些现象还没有深刻地揭露其本质,作出机理性解释。为了深入研究,本文提出一些值得研究的问题供参考,如:重离子径迹结构及能量沉积分布模型,DNA辐射敏感位点,质量沉积-分子改造,直接作用与间接作用,放射性核束的应用等。     

Heavy ion radiography and tomography

In the latest years, radiation therapy with ion beams has been rapidly spreading worldwide. This is mainly due to the favourable interaction properties of ion beams with matter, offering the possibility of more conformal dose deposition with superior sparing of healthy tissue in comparison to conventional photon radiation. Moreover, heavier ions like carbon offer a selective increase of biological effectiveness which can be advantageous for the treatment of tumours being resistant to sparsely ionizing radiation. However, full clinical exploitation of the advantages offered by ion beams is still challenged by the lack of exact knowledge of the beam range within the patient. Therefore, increasing research efforts are being devoted to the goal of reducing range uncertainties in ion beam therapy. In this context, ion transmission imaging is being recognized as a promising modality capable of providing valuable pre- (or even “in-between”) treatment information on the patient-specific stopping properties for indirect in-vivo range verification and low dose image guidance at the treatment site. The more recent availability of energetic ion beam sources at therapeutic treatment facilities, in combination with the advances in detector technologies and computational power, have considerably renewed the interest in this imaging technique. Nowadays, many research efforts are being devoted to the development of novel detector prototypes for heavy ion radiography and tomography, as will be reviewed in this contribution.     

Subcritical water extraction of barley to produce a functional drink

We investigated the effects of various temperatures between 150 and 280 degrees C during subcritical water extraction of barley to make a barley tea-like extract, a popular summer beverage in Japan. Each barley extract was analyzed for sensory properties, antioxidative activity, and the amount of residual matter, which revealed 205 degrees C to be the best extraction parameter. 5-Hydroxymethyl-2-furaldehyde was found to be the major antioxidative component in the 205 degrees C extract, along with the formation of several important amino acids.     

有机肥连续施用对菜田重金属行为的影响——基于地球化学模型研究

2017年起,农业部连续多年出台化肥减量增效行动工作方案,要求适当增加有机肥投入,发展循环农业。但连续施用的有机肥进入土壤后,会对土壤pH、有机质和重金属含量等产生影响,改变土壤重金属行为。科学评估有机肥料施用的影响至关重要。仅通过总含量评估重金属污染风险被认为是片面的,不同化学提取剂提取的重金属含量不能完全代表实际污染状况。地球化学模型具有良好的适用性,比传统的提取方法能够更全面地解释重金属的行为。在集约化农业种植区黄淮海平原,多次施用不同比例的粪源有机肥于旱地菜田,并引入地球化学模型,结合pH依赖性浸出试验,明确连续施肥对菜田土壤重金属行为的主要影响机制。研究发现,有机肥中的铜锌含量远高于土壤中的含量,施用后,它们在土壤中的淋溶浓度随着施用比例增加而显著增加,最多可超过十倍以上,并且活性大大增加,与施肥后溶解性有机物含量的升高呈正相关。不同处理条件下的土壤重金属浸出趋势相似：在中性pH下浸出浓度最低,然后逐渐向强酸和强碱增加,呈现出V型变化。地球化学模型LeachXS展示出较好的模拟结果,其模拟值与实测浓度具有良好的相关性(71.02%)。模拟结果显示,有机肥的施用不会明显改变重金...     

The Effects of Temperature and Heavy Water on Cell Division in Heat-Synchronized Cells of Tetrahymena*

SYNOPSIS. A study was undertaken of the rates of cell division of heat-synchronized cells of Tetrahymena pyriformis GL at various temperatures in water and 20, 30 and 40% heavy water. The results suggest that division rate is limited by a protein which undergoes both high and low temperature denaturation and that this protein is partially stabilized against heat-denaturation while becoming more susceptible to cold denaturation in the presence of heavy water. Thus, the optimum temperature for division shifts upward as the heavy water concentration is increased, with a maximum shift of 1 C occurring in 40% heavy water. In addition, division activity occurs in heavy water at 34 C, a temperature at which cells kept in water are blocked. Furthermore, the sharp increase in slope seen in the low temperature portion of Arrhenius plots of the data, occurs at higher temperatures when heavy water is present. Finally, at virtually all temperatures, except the highest, heavy water has a depressive effect on division rate indicating a general inhibitory influence of deuterium-substituted water on rate processes within the cell.     

重金属污染对土壤有机质积累的影响

采用田间采样分析与室内培养试验相结合的方法,研究了不同重金属污染土壤中有机质积累的差异及重金属污染强度对土壤有机质矿化动态变化的影响.结果表明：污染土壤中重金属的大量积累可减弱有机物质的矿化速率,增加土壤有机质的积累.土壤中颗粒态有机质及其占总有机碳的比例随重金属积累的增加而增加;而微生物生物量碳占总碳的比例却随土壤重金属污染水平的提高而下降.污染土壤中颗粒态有机质对重金属有显著的富集,这可能是影响土壤有机物质进一步矿化的原因之一.重金属污染可改变土壤有机质的矿化速率,影响土壤有机质的积累与分配.     

Biosorption of Lead from Industrial Wastewater Using Chrysophyllum albidum Seed Shell

The shell of the seed of Chrysophyllum albidum carbon was used to adsorb lead (Pb) from aqueous solution, the sorption process with respect to its equilibria and kinetics as well as the effects of pH, contact time, adsorbent mass, adsorbate concentration, and particle size on adsorption were also studied. The most effective pH range was found to be between 4.5 and 5 for the sorption of the metal ion. The first-order rate equation by Lagergren was tested on the kinetic data and the adsorption process followed first-order rate kinetics. Isotherm data were analyzed for possible agreement with the Langmuir and Freundlich adsorption isotherms; the Freundlich and Langmuir models for dynamics of metal ion uptake proposed in this work fitted the experimental data reasonably well. However, equilibrium sorption data were better represented by Langmuir model than Freundlich. The adsorption capacity calculated from Langmuir isotherm was 72.1 mg Pb (II) g^{- 1} at initial pH of 5.0 at 30°C for the particle size of 1.00 to 1.25 mm with the use of 2.0 g/100 ml adsorbent mass. The structural features of the adsorbent were characterized by Fourier transform infrared (FTIR) spectrometry; the presence of hydroxyl, carbonyl, amide, and phosphate groups confirms the potential mechanism adsorption of the adsorbent. This readily available adsorbent is efficient in the uptake of Pb (II) ion in aqueous solution, thus, it could be an excellent alternative for the removal of heavy metals and organic matter from water and wastewater.     

Ion channel behavior of amphotericin B in sterol-free and cholesterol- or ergosterol-containing supported phosphatidylcholine bilayer model membranes investigated by electrochemistry and spectroscopy

Amphotericin B (AmB) is a popular drug frequently applied in the treatment of systemic fungal infections. In the presence of ruthenium (II) as the maker ion, the behavior of AmB to form ion channels in sterol-free and cholesterol- or ergosterol-containing supported phosphatidylcholine bilayer model membranes were studied by cyclic votammetry, AC impedance spectroscopy, and UV/visible absorbance spectroscopy. Different concentrations of AmB ranging from a molecularly dispersed to a highly aggregated state of the drug were investigated. In a fixed cholesterol or ergosterol content (5 mol %) in glassy carbon electrode-supported model membranes, our results showed that no matter what form of AmB, monomeric or aggregated, AmB could form ion channels in supported ergosterol-containing phosphatidylcholine bilayer model membranes. However, AmB could not form ion channels in its monomeric form in sterol-free and cholesterol-containing supported model membranes. On the one hand, when AmB is present as an aggregated state, it can form ion channels in cholesterol-containing supported model membranes; on the other hand, only when AmB is present as a relatively highly aggregated state can it form ion channels in sterol-free supported phosphatidylcholine bilayer model membranes. The results showed that the state of AmB played an important role in forming ion channels in sterol-free and cholesterol-containing supported phosphatidylcholine bilayer model membranes.