The measurement of the confocal volume of a confocal three-dimensional micro-x-ray fluorescence(3D-XRF)setup is a key step in the field of confocal 3D-XRF analysis.With the development of x-ray facilities and optical ...The measurement of the confocal volume of a confocal three-dimensional micro-x-ray fluorescence(3D-XRF)setup is a key step in the field of confocal 3D-XRF analysis.With the development of x-ray facilities and optical devices,3D-XRF analysis with a micro confocal volume will create a great potential for 2D and 3D microstructural analysis and accurate quantitative analysis.However,the classic measurement method of scanning metal foils of a certain thickness leads to inaccuracy.A method for calibrating the confocal volume is proposed in this paper.The new method is based on the basic content of the textbook,and the theoretical results and the feasibility are given in detail for the 3D-XRF mono-chromatic x-ray condition and the poly-chromatic x-ray condition.We obtain a set of experimental confirmation using the poly-chromatic x-ray tube in the laboratory.It is proved that the sensitivity factor of the 3D-XRF can be directly and accurately obtained in a real calibration process.展开更多
Background: Nickel-induced allergic contact dermatitis (Ni-ACD) is a global health problem. More detailed knowledge on the skin uptake of haptens is required. This study aimed to investigate the penetration process an...Background: Nickel-induced allergic contact dermatitis (Ni-ACD) is a global health problem. More detailed knowledge on the skin uptake of haptens is required. This study aimed to investigate the penetration process and distribution of nickel in skin tissues with late phase and early phase of Ni-ACD to understand the mechanisms of metal allergy. Methods: Forty Hartley guinea pigs were divided into four groups according to the NiSO4 sensitizing concentration and the NiSO4 challenged concentration: the 5% NiSO4-group, 5% to 10%(sensitization-challenge;late phase group);10% NiSO4-group, 10% to 10%(sensitization-challenge;early-phase group);and the positive and negative controls. Pathological biopsies were performed on each group. The depth profile of nickel element concentration in the skin of guinea pigs was detected by synchrotron radiation micro X-ray fluorescence spectroscopy (SR-μ-XRF) and micro X-ray absorption near-edge spectroscopy (μ-XANES). Results: In each section, the nickel element concentration in both the 5% NiSO4-group and 10% NiSO4-group was significantly higher than that in the negative control group. In the upper 300-μm section of skin for the early phase group, the nickel element concentration was significantly higher than that in the lower section of skin. In deeper sections (>200 μm) of skin, the concentration of nickel in the early phase group was approximately equal to that in the late phase group. The curve of the late phase group was flat, which means that the nickel element concentration was distributed uniformly by SR-μ-XRF. According to the XANES data for the 10% NiSO4 metal salt solution, structural changes occurred in the skin model sample, indicating that nickel was not present in the Ni^2+ aqueous ionic state but in the nickel-binding protein. Conclusions: This study showed that the distribution of the nickel element concentration in ACD skin tissue was different between the early phase and late phase groups. The nickel element was not present in the Ni^2+ aqueous ionic state but bound with certain proteins to form a complex in the stratum corneum in ACD model tissue.展开更多
This paper discusses some preliminary results regarding raw materials used in ancient glass mosaic tesserae. The studied glass tesserae were recovered during the archeological excavation of the mosaics at the Christia...This paper discusses some preliminary results regarding raw materials used in ancient glass mosaic tesserae. The studied glass tesserae were recovered during the archeological excavation of the mosaics at the Christian basilicas in Byllis, Lin and Elbasan, which according to the archeologists were built between the end of Vth and beginning of VIth century AD. In the recent years, several studies are performed on opaque coloured glass but in Albania only few studies are performed in this field. These samples are analyzed using optical microscopy and micro X-ray fluorescence. Optical microscopy is used to analyse the microstructure of the glass tesserae. The main elements and trace elements are determined qualitatively from measurements performed with micro X-ray fluorescence. The glass matrix resulted to be very heterogeneous with too many inclusions dispersed on it. Several elements which are responsible for the color and opacity of glass tesserae are determined. Comparisons are made between the same colors of glass tesserae from different archaeological sites.展开更多
Global rice production practices have gradually changed from a reliance on transplanting to direct seeding.Yet how this shift may alter cadmium(Cd)accumulation in rice is poorly known.Here we conducted field experimen...Global rice production practices have gradually changed from a reliance on transplanting to direct seeding.Yet how this shift may alter cadmium(Cd)accumulation in rice is poorly known.Here we conducted field experiments with two rice genotypes cultivars that were planted using three methods:via direct seeding(DS),seedling throwing(ST),and manual transplanting(MT).Rice samples were collected during four growth stages.The formation and distribution of iron plaque were analyzed using DCB(dithionite-citrate-bicarbonate)extractions and observed under micro-XRF(micro X-ray fluorescence).The results revealed that,in each growth stage,DS rice was more apt to harbor Cd distributed in the plant’s aerial parts,and the Cd concentration of brown rice from DS was 21.8%–43.3%significantly higher than those from ST and MT at maturity stage(p<0.05).During the vegetative stages,the Cd uptake percentage was higher in DS than MT rice,and those plants arising from the DS method were capable of absorbing more Cd earlier in their growth and development.Conversely,using DS decreased the amount of iron plaque covering the root surface in every growth stage,especially in the critical period of Cd accumulation,such that the roots’middle areas were distinguished by a near-complete absence of iron plaque,thus weakening its role as an effective barrier to Cd uptake from soil.Collectively,this study demonstrated that implementing the DS mode of planting will increase Cd’s distribution in the aboveground parts of rice,and heightening the risk of Cd contamination in grain.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11675019 and 11875087).
文摘The measurement of the confocal volume of a confocal three-dimensional micro-x-ray fluorescence(3D-XRF)setup is a key step in the field of confocal 3D-XRF analysis.With the development of x-ray facilities and optical devices,3D-XRF analysis with a micro confocal volume will create a great potential for 2D and 3D microstructural analysis and accurate quantitative analysis.However,the classic measurement method of scanning metal foils of a certain thickness leads to inaccuracy.A method for calibrating the confocal volume is proposed in this paper.The new method is based on the basic content of the textbook,and the theoretical results and the feasibility are given in detail for the 3D-XRF mono-chromatic x-ray condition and the poly-chromatic x-ray condition.We obtain a set of experimental confirmation using the poly-chromatic x-ray tube in the laboratory.It is proved that the sensitivity factor of the 3D-XRF can be directly and accurately obtained in a real calibration process.
基金the grants from National Natural Science Foundation of China (No.81373175)CAMS Innovation Fund for Medical Sciences (No.2016-I2M-1003).
文摘Background: Nickel-induced allergic contact dermatitis (Ni-ACD) is a global health problem. More detailed knowledge on the skin uptake of haptens is required. This study aimed to investigate the penetration process and distribution of nickel in skin tissues with late phase and early phase of Ni-ACD to understand the mechanisms of metal allergy. Methods: Forty Hartley guinea pigs were divided into four groups according to the NiSO4 sensitizing concentration and the NiSO4 challenged concentration: the 5% NiSO4-group, 5% to 10%(sensitization-challenge;late phase group);10% NiSO4-group, 10% to 10%(sensitization-challenge;early-phase group);and the positive and negative controls. Pathological biopsies were performed on each group. The depth profile of nickel element concentration in the skin of guinea pigs was detected by synchrotron radiation micro X-ray fluorescence spectroscopy (SR-μ-XRF) and micro X-ray absorption near-edge spectroscopy (μ-XANES). Results: In each section, the nickel element concentration in both the 5% NiSO4-group and 10% NiSO4-group was significantly higher than that in the negative control group. In the upper 300-μm section of skin for the early phase group, the nickel element concentration was significantly higher than that in the lower section of skin. In deeper sections (>200 μm) of skin, the concentration of nickel in the early phase group was approximately equal to that in the late phase group. The curve of the late phase group was flat, which means that the nickel element concentration was distributed uniformly by SR-μ-XRF. According to the XANES data for the 10% NiSO4 metal salt solution, structural changes occurred in the skin model sample, indicating that nickel was not present in the Ni^2+ aqueous ionic state but in the nickel-binding protein. Conclusions: This study showed that the distribution of the nickel element concentration in ACD skin tissue was different between the early phase and late phase groups. The nickel element was not present in the Ni^2+ aqueous ionic state but bound with certain proteins to form a complex in the stratum corneum in ACD model tissue.
文摘This paper discusses some preliminary results regarding raw materials used in ancient glass mosaic tesserae. The studied glass tesserae were recovered during the archeological excavation of the mosaics at the Christian basilicas in Byllis, Lin and Elbasan, which according to the archeologists were built between the end of Vth and beginning of VIth century AD. In the recent years, several studies are performed on opaque coloured glass but in Albania only few studies are performed in this field. These samples are analyzed using optical microscopy and micro X-ray fluorescence. Optical microscopy is used to analyse the microstructure of the glass tesserae. The main elements and trace elements are determined qualitatively from measurements performed with micro X-ray fluorescence. The glass matrix resulted to be very heterogeneous with too many inclusions dispersed on it. Several elements which are responsible for the color and opacity of glass tesserae are determined. Comparisons are made between the same colors of glass tesserae from different archaeological sites.
基金supported by grants from the National Natural Science Foundation of China(Nos.42077142 and 41701366)the Changsha Plan Project of Science and Technology(kq1801025).
文摘Global rice production practices have gradually changed from a reliance on transplanting to direct seeding.Yet how this shift may alter cadmium(Cd)accumulation in rice is poorly known.Here we conducted field experiments with two rice genotypes cultivars that were planted using three methods:via direct seeding(DS),seedling throwing(ST),and manual transplanting(MT).Rice samples were collected during four growth stages.The formation and distribution of iron plaque were analyzed using DCB(dithionite-citrate-bicarbonate)extractions and observed under micro-XRF(micro X-ray fluorescence).The results revealed that,in each growth stage,DS rice was more apt to harbor Cd distributed in the plant’s aerial parts,and the Cd concentration of brown rice from DS was 21.8%–43.3%significantly higher than those from ST and MT at maturity stage(p<0.05).During the vegetative stages,the Cd uptake percentage was higher in DS than MT rice,and those plants arising from the DS method were capable of absorbing more Cd earlier in their growth and development.Conversely,using DS decreased the amount of iron plaque covering the root surface in every growth stage,especially in the critical period of Cd accumulation,such that the roots’middle areas were distinguished by a near-complete absence of iron plaque,thus weakening its role as an effective barrier to Cd uptake from soil.Collectively,this study demonstrated that implementing the DS mode of planting will increase Cd’s distribution in the aboveground parts of rice,and heightening the risk of Cd contamination in grain.
