BACKGROUND Traditional methods cannot clearly visualize esophageal cancer(EC)tumor contours and metastases,which limits the clinical application of da Vinci robotassisted surgery.AIM To investigate the efficacy of the...BACKGROUND Traditional methods cannot clearly visualize esophageal cancer(EC)tumor contours and metastases,which limits the clinical application of da Vinci robotassisted surgery.AIM To investigate the efficacy of the da Vinci robot in combination with nanocarbon lymph node tracers in radical surgery of EC.METHODS In total,104 patients with early-stage EC who were admitted to Liuzhou worker's Hospital from January 2020 to June 2023 were enrolled.The patients were assigned to an observation group(n=52),which underwent da Vinci robot-assisted minimally invasive esophagectomy(RAMIE)with the intraoperative use of nanocarbon tracers,and a control group(n=52),which underwent traditional surgery treatment.The operation time,intraoperative blood loss,postoperative drainage tube indwelling time,hospital stay,number of lymph nodes dissected,incidence of complications,and long-term curative effects were comparatively analyzed.The postoperative stress response C-reactive protein(CRP),cortisol,epinephrine(E)and inflammatory response interleukin(IL)-6,IL-8,IL-10,and tumor necrosis factor-alpha(TNF-α)were evaluated.RESULTS Compared with the control group,the observation group had significantly lower postoperative CRP,cortisol,and E levels(P<0.05)with a milder inflammatory response,as indicated by lower IL-6,IL-10,and TNF-αlevels(P<0.05).Patients who underwent RAMIE had less intraoperative blood loss and shorter operation times and hospital stays than those who underwent traditional surgery.The average number of dissected lymph nodes,time of lymph node dissection,and mean smallest lymph node diameter were all significantly lower in the observation group(P<0.05).The rate of postoperative complications was 5.77%in the observation group,significantly lower than the 15.38%observed in the control group.Furthermore,the lymphatic metastasis rate,reoperation rate,and 12-and 24-month cumulative mortality in the observation group were 1.92%,0%,0%,and 0%,respectively,all of which were significantly lower than those in the control group(P<0.05).CONCLUSION The treatment of EC using the da Vinci robot combined with nanocarbon lymph node tracers can achieve good surgical outcomes and demonstrates promising clinical applications.展开更多
Groundwater residence time is a fundamental property of groundwater to understand important hydrogeological issues,such as deriving sustainable abstraction volumes,or,the evolution of groundwater quality.The anthropog...Groundwater residence time is a fundamental property of groundwater to understand important hydrogeological issues,such as deriving sustainable abstraction volumes,or,the evolution of groundwater quality.The anthropogenic trace gases chlorofluorocarbons (CFC-11,CFC-12 and CFC-113) and sulphur hexafluoride (SF6) are ideal in this regard because they have been released globally at known rates and become dissolved in groundwater following Henry’s Law,integrating over large spatial (global) and temporal (decades) scales.The CFCs and SF6 are able to date groundwater up to w100 years old with the caveat of certain simplifying assumptions.However,the inversion of environmental tracer concentrations (CFCs and SF6) to derive groundwater age rests on the accurate determination of groundwater recharge parameters,namely temperature,elevation,salinity and excess air,in addition to resolving the potential for contamination,degradation and unsaturated zone effects.This review explores the fundamentals of CFC-11,CFC-12,CFC-113 and SF6 as environmental tracers of groundwater age and recommends complementary techniques throughout.Once this relatively simple and inexpensive technique has been used to determine initial concentrations at the recharge zone,setting the groundwater dating ‘clock’ to zero,this review then explores the meaning of groundwater ‘age’ in relation to measured environmental tracer concentrations.It is shown that the CFCs and SF6 may be applied to a wide-range of hydrogeological problems and suggests that environmental tracers are particularly powerful tools when integrated with numerical flow and transport models.展开更多
The production of bright light, with vivid color, is the primary purpose of signaling, illuminating devices,and fire control purposes. This study, reports on the development of red flame compositions with enhanced per...The production of bright light, with vivid color, is the primary purpose of signaling, illuminating devices,and fire control purposes. This study, reports on the development of red flame compositions with enhanced performance in terms of luminous intensity, and color quality. The light intensity and the imprint spectra of developed red flame compositions to standard NATO red tracer(R-284 NATO) were measured using digital luxmeter, and UV-Vis. spectrometer. The main giving of this study is that the light intensity of standard NATO red tracer was increased by 72%, the color quality was also improved by60%(over the red band from 650 to 780 nm). This enhanced spectral performance was achieved by means of deriving the combustion process to maximize the formation of red color emitting species in the combustion flame. Thanks to the optimum ratio of color source to color intensifier using aluminum metal fuel; this approach offered the highest intensity and color quality. Upon combustion, aluminum was found to maximize the formation SrCL(the main reactive red color emitting species) and to minimize the interfering incandescent emission resulted from MgO and SrO. Quantification of active red color emitting species in the combustion flame was conducted using chemical equilibrium thermodynamic code named ICT. The improvement in red flare performance, established the rule that the color intensifier should be in the range from 10 to 15 Wt % of the total composition.展开更多
High-precision isotope composition determinations using multicollector, magnetic-sector induc- tively coupled plasma mass spectrometry (MC-ICPMS) have recently revealed that some transition metal isotopes such as thos...High-precision isotope composition determinations using multicollector, magnetic-sector induc- tively coupled plasma mass spectrometry (MC-ICPMS) have recently revealed that some transition metal isotopes such as those of Mo, Fe, Cu, Zn etc. can be used as biogeochemical tracers in global change research. The Mo isotope system may be useful in paleoredox investigations indicating that δ97/95Mo in seawater may co-vary with changes in the relative proportions of anoxic and oxic sedimentation in the ocean, and that this variation may be recorded inδ97/95Mo of anoxic sediments. The Mo continental flux into the oceans and the global Mo isotope budget can be estimated fromδ97/95Mo values. The Fe isotope composition in seawater is an important issue because Fe plays a controlling role in biological productivity in the oceans and its abundance in seawater may have substantial effect on climate changes. Iron isotope fractionations could result from bio- and abio-processes and have about 0.1% variation (δ56/54Fe), so Fe isotopes considered alone cannot be used to distinguish the products of abiotic and biotic Fe processing in geological records. Cu and Zn isotopes are also used as biogeochemical tracers, but the researches are relatively less. This review mainly focuses on the methods for preparation, purification and determination of new isotope tracer samples, and on isotope applications in marine environmental changes.展开更多
Over 100,000,000 people worldwide are exposed to high arsenic groundwater utilised for drinking or cooking.The consequent global avoidable disease burden is estimated to be of the order of 100,000 avoidable deaths or ...Over 100,000,000 people worldwide are exposed to high arsenic groundwater utilised for drinking or cooking.The consequent global avoidable disease burden is estimated to be of the order of 100,000 avoidable deaths or more per annum from just direct exposures - i.e.excluding indirect exposure (from rice and other foods) and excluding morbidity.Notwithstanding 1000s of papers published on arsenic (hydro)(bio)geochemistry,there remain a number of key outstanding questions to be addressed in relation to arsenic geoscience - these include questions related to:(i) the role of human activities - irrigation,agriculture and other land uses - on arsenic mobilisation in groundwaters;(ii) the specific sources,nature and role of organics,minerals and microbial communities involved in arsenic mobilisation;(iii) the relationship to microscopic to macroscopic scale geological (including tectonic) and evolution processes;(iv) unravelling the over-printing of multiple processes in complex highly heterogeneous aquifer systems and (v) using increasing understanding of the controls of arsenic mobility in groundwaters systems to informing improved locally-relevant remediation and mitigation approaches.This article further summarises how the 9 further papers in this Special Issue address some of these questions through the use of chemical and/or isotopic tracers.展开更多
The purpose of this study was to investigate the effect of four fluorescent dyes, True Blue(TB), Fluoro-Gold(FG), Fluoro-Ruby(FR), and 1,1′-dioctadecyl-3,3,3′,3′-tetramethylindocarbocyanine perchlorate(Di I...The purpose of this study was to investigate the effect of four fluorescent dyes, True Blue(TB), Fluoro-Gold(FG), Fluoro-Ruby(FR), and 1,1′-dioctadecyl-3,3,3′,3′-tetramethylindocarbocyanine perchlorate(Di I), in retrograde tracing of rat spinal motor neurons. We transected the muscle branch of the rat femoral nerve and applied each tracer to the proximal stump in single labeling experiments, or combinations of tracers(FG-Di I and TB-Di I) in double labeling experiments. In the single labeling experiments, significantly fewer labeled motor neurons were observed after FR labeling than after TB, FG, or Di I, 3 days after tracer application. By 1 week, there were no significant differences in the number of labeled neurons between the four groups. In the double-labeling experiment, the number of double-labeled neurons in the FG-Di I group was not significantly different from that in the TB-Di I group 1 week after tracer application. Our findings indicate that TB, FG, and Di I have similar labeling efficacies in the retrograde labeling of spinal motor neurons in the rat femoral nerve when used alone. Furthermore, combinations of Di I and TB or FG are similarly effective. Therefore, of the dyes studied, TB, FG and Di I, and combinations of Di I with TB or FG, are the most suitable for retrograde labeling studies of motor neurons in the rat femoral nerve.展开更多
Non-invasive cardiac imaging has explored enormous advances in the last few decades.In particular,hybrid imaging represents the fusion of information from multiple imaging modalities,allowing to provide a more compreh...Non-invasive cardiac imaging has explored enormous advances in the last few decades.In particular,hybrid imaging represents the fusion of information from multiple imaging modalities,allowing to provide a more comprehensive dataset compared to traditional imaging techniques in patients with cardiovascular diseases.The complementary anatomical,functional and molecular information provided by hybrid systems are able to simplify the evaluation procedure of various pathologies in a routine clinical setting.The diagnostic capability of hybrid imaging modalities can be further enhanced by introducing novel and specific imaging biomarkers.The aim of this review is to cover the most recent advancements in radiotracers development for SPECT/CT,PET/CT,and PET/MRI for cardiovascular diseases.展开更多
The Aburrá Valley region in Colombia, with Medellín as its main city, is an urban centre with about three million people. An investigation was carried out to deter-mine a set of baseline concentrations for V...The Aburrá Valley region in Colombia, with Medellín as its main city, is an urban centre with about three million people. An investigation was carried out to deter-mine a set of baseline concentrations for VOC compounds associated with diesel fuel and gasoline, as vehicular emission tracers in the region. The VOC measurement campaigns, based on TENAX tube sampling and analysis according to TO-17 EPA method, were done in areas of low and high vehicular flow as well as on-board measurements covering major Medellín road networks during 24 hours. The results showed that there was a relation between VOCs concentrations and vehicular activi-ty. The diesel fuel sulfur content was also found as an important factor on VOC hy-drocarbon formation.展开更多
Fluorescent neuronal tracers should not be toxic to the nervous system when used in long-term labeling. Previous studies have addressed tracer toxicity, but whether tracers injected into an intact nerve result in func...Fluorescent neuronal tracers should not be toxic to the nervous system when used in long-term labeling. Previous studies have addressed tracer toxicity, but whether tracers injected into an intact nerve result in functional impairment remains to be elucidated. In the present study, we examined the functions of motor, sensory and autonomic nerves following the application of 5% Fluoro-Gold, 4% True Blue and 10% Fluoro-Ruby (5 pL) to rat tibial nerves via pressure injection. A set of evaluation methods including walking track analysis, plantar test and laser Doppler perfusion imaging was used to determine the action of the fluorescent neuronal tracers. Additionally, nerve pathology and ratio of muscle wet weight were also observed. Results showed that injection of Fluoro-Gold significantly resulted in loss of motor nerve function, lower plantar sensibility, increasing blood flow volume and higher neurogenic vasodilatation. Myelinated nerve fiber degeneration, unclear boundaries in nerve fibers and high retrograde labeling efficacy were observed in the Fluoro-Gold group. The True Blue group also showed obvious neurogenic vasodilatation, but less severe loss of motor function and degeneration, and fewer labeled motor neurons were found compared with the Fluoro-Gold group. No anomalies of motor and sensory nerve function and no myelinated nerve fiber degeneration were observed in the Fluoro-Ruby group. Experimental findings indicate that Fluoro-Gold tracing could lead to significant functional impairment of motor, sensory and autonomic nerves, while functional impairment was less severe following True Blue tracing. Fluoro-Ruby injection appears to have no effect on neurological function.展开更多
Rare earth elements (REE) were used to study the temporal and spatial processes of soil erosion from different depths and sections of a slope. Two simulated rainfall events were applied to a prepared plot with a slope...Rare earth elements (REE) were used to study the temporal and spatial processes of soil erosion from different depths and sections of a slope. Two simulated rainfall events were applied to a prepared plot with a slope of 22°. The total runoff and sediment yield were collected every minute during the rainfall events. During the first twenty minutes of the first rainfall event, the average rate of rill erosion and the accumulated sediment yield due to rill erosion was 0.5 and 0.3 times higher than for sheet erosion. During this time, most of the erosion occurred on the lower one third of the plot. After 20 min, rill erosion became the dominant process on the slope. The average acceleration in the rate of rill erosion, the rate of rill erosion and the accumulated sediment yield due to rill erosion were 42, 6 and 4 times higher than that of sheet erosion, respectively. During the first 35 minutes of the second rainfall event, the average acceleration in the rate of rill erosion was 6~9 times higher than that of sheet erosion. Afterwards, the slope became nearly stable with little change in either rill or sheet erosion rates. Initially, most of the rill erosion occurred in the lower third of the slope but later the preexisting rillhead in the middle section of the slope became reactivated and erosion in this section of the slope increased rapidly. These results indicate that REE tracer technology is a valuable tool for quantifying spatial and temporal changes in erosion from a soil slope.展开更多
Glial cells play an essential part in the neuron system.They can not only serve as structural blocks in the human brain but also participate in many biological processes.Extensive studies have shown that astrocytes an...Glial cells play an essential part in the neuron system.They can not only serve as structural blocks in the human brain but also participate in many biological processes.Extensive studies have shown that astrocytes and microglia play an important role in neurodegenerative diseases,such as Alzheimer's disease,Parkinson's disease,Huntington's disease,as well as glioma,epilepsy,ischemic stroke,and infections.Positron emission tomography is a functional imaging technique providing molecular-level information before anatomic changes are visible and has been widely used in many above-mentioned diseases.In this review,we focus on the positron emission tomography tracers used in pathologies related to glial cells,such as glioma,Alzheimer's disease,and neuroinflammation.展开更多
Direct measurement of slip length is based on the measured fluid velocity near solid boundary. However, previous micro particle image velocimetry/particle tracking velocimetry (microPIV/PTV) measurements have report...Direct measurement of slip length is based on the measured fluid velocity near solid boundary. However, previous micro particle image velocimetry/particle tracking velocimetry (microPIV/PTV) measurements have reported surprisingly large measured near-wall velocities of pressure-driven flow in apparent contradiction with the no-slip hy-pothesis and experimental results from other techniques. To better interpret the measured results of the microPIV/PTV, we performed velocity profile measurements near a hy-drophilic wall (z = 0.25-1.5 μm) with two sizes of tracer particles (φ 50 nm and φ200 nm). The experimental results indicate that, at less than 1 μm from the wall, the deviations between the measured velocities and no-slip theoretical values obviously decrease from 93% of φ200 nm particles to 48% of φ50 nm particles. The Boltzmann-like exponential measured particle concentrations near wall were found. Based on the non linear Boltzmann distribution of particle concentration and the effective focus plane thickness, we illustrated the reason of the apparent velocity increase near wall and proposed a method to correct the measured velocity profile. By this method, the deviations between the corrected measured velocities and the no-slip theoretical velocity decrease from 45.8% to 10%, and the measured slip length on hy-drophilic glass is revised from 75 nm to 16 nm. These results indicated that the particle size and the biased particle concentration distribution can significantly affect near wall velocity measurement via microPIV/PTV, and result in larger measured velocity and slip length close to wall.展开更多
Rare earth element(REE) tracer method was used to study sheet erosion changing to rill erosion on slope land. By placing different REE on different soil depth across a slope in an indoor plot, two simulated rainfalls ...Rare earth element(REE) tracer method was used to study sheet erosion changing to rill erosion on slope land. By placing different REE on different soil depth across a slope in an indoor plot, two simulated rainfalls were applied to study the change of erosion type and the rill erosion process. The results indicate that the main erosion type is sheet erosion at the beginning of the rainfalls, and serious erosion happens after rill erosion appears. Accumulated sheet and rill erosion amount increases with the rainfalls time. The percentage of sheet erosion amount decreases and rill erosion percentage increases with time. At the end of the rainfalls, the total rill erosion amounts are 4.3 and 5 times more than sheet erosion. In this paper, a new REE tracer method was used to quantitatively distinguish sheet and rill erosion amount. The new REE tracer method should be useful to future studying of erosion processes on slope lands.展开更多
We report the use of CaTiO_(3):Pr^(3+)multiband persistent luminescent nanoparticles,which can simultaneously emit red(610 nm),near-infrared(893 nm),and short-wave infrared(1040 nm)photoluminescence and persistent lum...We report the use of CaTiO_(3):Pr^(3+)multiband persistent luminescent nanoparticles,which can simultaneously emit red(610 nm),near-infrared(893 nm),and short-wave infrared(1040 nm)photoluminescence and persistent luminescence,as the tracer nanoagents for water tracer sensing.By using a spectrofluorometer,an Si charge-coupled device(CCD)camera and an InGaAs array camera as the detection tools,we evaluated the sensing capabilities of the three emission bands of CaTiO_(3):Pr^(3+)nanoparticles in brine water solutions and crude oil/brine water emulsions in both photoluminescence mode and persistent luminescence mode.Among these different detection combinations,the persistent luminescence-based Si CCD camera imaging exhibits the best sensing performance with the detection limits being at a single-digit ppb level for the 610 and 893 nm bands and about 100–200 ppb for the 1040 nm band in both water solutions and crude oil/water emulsions,while the photoluminescencebased Si CCD camera imaging has a much higher detection limit of~10 ppm in water solutions and of~200 ppm in oil/water emulsions.The persistent luminescence-based InGaAs array camera imaging to the 1040 nm band has the worst performance with the detection limits higher than 200 ppm for both solutions.The sensing performances of the spectrofluorometer to photoluminescence signals and persistent luminescence signals in the two solutions are about the same,with the detection limits being around 100–200 ppm.展开更多
The increasing popularity of endoscopic submucosal dissection(ESD)as a treatment for early gastric cancer has highlighted the importance of quality assessment in achieving curative resections.This article emphasizes t...The increasing popularity of endoscopic submucosal dissection(ESD)as a treatment for early gastric cancer has highlighted the importance of quality assessment in achieving curative resections.This article emphasizes the significance of evaluating ESD quality,not only for curative cases but also for non-curative ones.Postoperative assessment relies on the endoscopic curability(eCura)classification,but management strategies for eCuraC-1 tumour with a positive horizontal margin are unclear.Current research primarily focuses on comparing additional surgical procedures in high-risk patients,while studies specifically targeting eCuraC-1 patients are limited.Exploring management strategies and follow-up outcomes for such cases could provide valuable insights.Furthermore,the application of molecular imaging using near-infrared fluorescent tracers holds promise for precise tumour diagnosis and navigation,potentially impacting the management of early-stage gastric cancer patients.Advancing research in these areas is essential for improving the overall efficacy of endoscopic techniques and refining treatment indications.展开更多
Formaldehyde(HCHO) is one of the most important intermediate products of atmospheric photochemical reactions in the troposphere, therefore understanding of HCHO sources is essential for effective ozone control measu...Formaldehyde(HCHO) is one of the most important intermediate products of atmospheric photochemical reactions in the troposphere, therefore understanding of HCHO sources is essential for effective ozone control measures. The objective of this work is to distinguish between primary and secondary sources of HCHO. Based on about one month of online measurements in winter in Ziyang,Sichuan, the multi-linear regression analysis of ambient concentrations of HCHO and possible tracers(acetonitrile, propane and peroxyacetyl nitrate) was performed. The results show that during winter in Ziyang, biomass burning contributed an average of 53.2% to ambient HCHO levels, while secondary processes contributed about 30.1%, and vehicular sources accounted for 7.1%.展开更多
Complete and comprehensive information about sediment dynamic and identification of hotspots of sediment production and transport are necessary for understanding the erosion processes and increasing the efficiency of ...Complete and comprehensive information about sediment dynamic and identification of hotspots of sediment production and transport are necessary for understanding the erosion processes and increasing the efficiency of soil and water conservation practices.Numerous studies used the sediment fingerprint techniques to investigate the contribution of different sources in suspended and bed sediment yield of the watersheds.However,the contribution of various land use/land covers in suspended and bed sediment yield for the great Caspian Sea basin is in an aura of ambiguity and the present study was conducted to gather information about an important part of this area in northern Iran,where rangelands are located upstream of Hyrcanian forests and dense agricultural lands are located downstream.The surface soil of different land use/land covers including forest,rangeland,agriculture and streambank lands were sampled in 30 points.Suspended and bed sediments were sampled in the watershed outlet in two high and low water periods.Geochemical characteristics of soil and sediment samples containing 59 elements were measured using ICP-OES GBC Integra.The reliable and suitable tracers from 59 elements were then selected using Range test,Kruskal-Wallis and Discriminant Function Analysis,respectively,in FingerPro package of R software.The results showed that for suspended sediment,streambank and rangeland had the highest contributions of 86.2%and 47.5%,respectively,in two high and low water periods.For bed sediment,in two high and low water periods,rangeland and streambank had the highest contributions of 73.8%and 84.4%,respectively.Land use change and especially human activities such as agriculture,road construction and development of residential areas along the main river riparian zone has led to a significant increase in suspended and bed sediments.展开更多
If an explicit time scheme is used in a numerical model, the size of the integration time step is typically limited by the spatial resolution. This study develops a regular latitude–longitude grid-based global three-...If an explicit time scheme is used in a numerical model, the size of the integration time step is typically limited by the spatial resolution. This study develops a regular latitude–longitude grid-based global three-dimensional tracer transport model that is computationally stable at large time-step sizes. The tracer model employs a finite-volume flux-form semiLagrangian transport scheme in the horizontal and an adaptively implicit algorithm in the vertical. The horizontal and vertical solvers are coupled via a straightforward operator-splitting technique. Both the finite-volume scheme's onedimensional slope-limiter and the adaptively implicit vertical solver's first-order upwind scheme enforce monotonicity. The tracer model permits a large time-step size and is inherently conservative and monotonic. Idealized advection test cases demonstrate that the three-dimensional transport model performs very well in terms of accuracy, stability, and efficiency. It is possible to use this robust transport model in a global atmospheric dynamical core.展开更多
基金Supported by Guangxi Health Department Scientific Research Program,No.Z20200206Project of Guangxi Liuzhou Science and Technology Bureau,No.2024YB0101B010。
文摘BACKGROUND Traditional methods cannot clearly visualize esophageal cancer(EC)tumor contours and metastases,which limits the clinical application of da Vinci robotassisted surgery.AIM To investigate the efficacy of the da Vinci robot in combination with nanocarbon lymph node tracers in radical surgery of EC.METHODS In total,104 patients with early-stage EC who were admitted to Liuzhou worker's Hospital from January 2020 to June 2023 were enrolled.The patients were assigned to an observation group(n=52),which underwent da Vinci robot-assisted minimally invasive esophagectomy(RAMIE)with the intraoperative use of nanocarbon tracers,and a control group(n=52),which underwent traditional surgery treatment.The operation time,intraoperative blood loss,postoperative drainage tube indwelling time,hospital stay,number of lymph nodes dissected,incidence of complications,and long-term curative effects were comparatively analyzed.The postoperative stress response C-reactive protein(CRP),cortisol,epinephrine(E)and inflammatory response interleukin(IL)-6,IL-8,IL-10,and tumor necrosis factor-alpha(TNF-α)were evaluated.RESULTS Compared with the control group,the observation group had significantly lower postoperative CRP,cortisol,and E levels(P<0.05)with a milder inflammatory response,as indicated by lower IL-6,IL-10,and TNF-αlevels(P<0.05).Patients who underwent RAMIE had less intraoperative blood loss and shorter operation times and hospital stays than those who underwent traditional surgery.The average number of dissected lymph nodes,time of lymph node dissection,and mean smallest lymph node diameter were all significantly lower in the observation group(P<0.05).The rate of postoperative complications was 5.77%in the observation group,significantly lower than the 15.38%observed in the control group.Furthermore,the lymphatic metastasis rate,reoperation rate,and 12-and 24-month cumulative mortality in the observation group were 1.92%,0%,0%,and 0%,respectively,all of which were significantly lower than those in the control group(P<0.05).CONCLUSION The treatment of EC using the da Vinci robot combined with nanocarbon lymph node tracers can achieve good surgical outcomes and demonstrates promising clinical applications.
基金supported by a Natural Environment Research Council(NERC) Collaborative Awards in Science and Engineering (CASE) studentship(NE/EEA6549/1)
文摘Groundwater residence time is a fundamental property of groundwater to understand important hydrogeological issues,such as deriving sustainable abstraction volumes,or,the evolution of groundwater quality.The anthropogenic trace gases chlorofluorocarbons (CFC-11,CFC-12 and CFC-113) and sulphur hexafluoride (SF6) are ideal in this regard because they have been released globally at known rates and become dissolved in groundwater following Henry’s Law,integrating over large spatial (global) and temporal (decades) scales.The CFCs and SF6 are able to date groundwater up to w100 years old with the caveat of certain simplifying assumptions.However,the inversion of environmental tracer concentrations (CFCs and SF6) to derive groundwater age rests on the accurate determination of groundwater recharge parameters,namely temperature,elevation,salinity and excess air,in addition to resolving the potential for contamination,degradation and unsaturated zone effects.This review explores the fundamentals of CFC-11,CFC-12,CFC-113 and SF6 as environmental tracers of groundwater age and recommends complementary techniques throughout.Once this relatively simple and inexpensive technique has been used to determine initial concentrations at the recharge zone,setting the groundwater dating ‘clock’ to zero,this review then explores the meaning of groundwater ‘age’ in relation to measured environmental tracer concentrations.It is shown that the CFCs and SF6 may be applied to a wide-range of hydrogeological problems and suggests that environmental tracers are particularly powerful tools when integrated with numerical flow and transport models.
基金funding the research project entitled"Enhanced Visible Tracers for Illumination and Tracking"
文摘The production of bright light, with vivid color, is the primary purpose of signaling, illuminating devices,and fire control purposes. This study, reports on the development of red flame compositions with enhanced performance in terms of luminous intensity, and color quality. The light intensity and the imprint spectra of developed red flame compositions to standard NATO red tracer(R-284 NATO) were measured using digital luxmeter, and UV-Vis. spectrometer. The main giving of this study is that the light intensity of standard NATO red tracer was increased by 72%, the color quality was also improved by60%(over the red band from 650 to 780 nm). This enhanced spectral performance was achieved by means of deriving the combustion process to maximize the formation of red color emitting species in the combustion flame. Thanks to the optimum ratio of color source to color intensifier using aluminum metal fuel; this approach offered the highest intensity and color quality. Upon combustion, aluminum was found to maximize the formation SrCL(the main reactive red color emitting species) and to minimize the interfering incandescent emission resulted from MgO and SrO. Quantification of active red color emitting species in the combustion flame was conducted using chemical equilibrium thermodynamic code named ICT. The improvement in red flare performance, established the rule that the color intensifier should be in the range from 10 to 15 Wt % of the total composition.
基金Project supported by Qingdao special project for outstanding young scientists (04-3-JJ-03), "100 Talents Project " and the Science Innovation Key Projects of the Chinese Academy of Sciences (No. KZCX1-SW- 01-08) and the National Science Foundation for Young Scientists of China (No.49925614).
文摘High-precision isotope composition determinations using multicollector, magnetic-sector induc- tively coupled plasma mass spectrometry (MC-ICPMS) have recently revealed that some transition metal isotopes such as those of Mo, Fe, Cu, Zn etc. can be used as biogeochemical tracers in global change research. The Mo isotope system may be useful in paleoredox investigations indicating that δ97/95Mo in seawater may co-vary with changes in the relative proportions of anoxic and oxic sedimentation in the ocean, and that this variation may be recorded inδ97/95Mo of anoxic sediments. The Mo continental flux into the oceans and the global Mo isotope budget can be estimated fromδ97/95Mo values. The Fe isotope composition in seawater is an important issue because Fe plays a controlling role in biological productivity in the oceans and its abundance in seawater may have substantial effect on climate changes. Iron isotope fractionations could result from bio- and abio-processes and have about 0.1% variation (δ56/54Fe), so Fe isotopes considered alone cannot be used to distinguish the products of abiotic and biotic Fe processing in geological records. Cu and Zn isotopes are also used as biogeochemical tracers, but the researches are relatively less. This review mainly focuses on the methods for preparation, purification and determination of new isotope tracer samples, and on isotope applications in marine environmental changes.
基金support from EPSRC (GR/S30207/01)NERC(NE/ J023833/1, NE/P01304X/1)+2 种基金DST-NERC-Newton Bhabha(NE/ R003386/1)(FAR-GANGA)the British Council (SA07/09) (UKIERI PRAMA)the European Union(MRTN-CT-2006-035420, KH/ Asia-Link/04 142966)
文摘Over 100,000,000 people worldwide are exposed to high arsenic groundwater utilised for drinking or cooking.The consequent global avoidable disease burden is estimated to be of the order of 100,000 avoidable deaths or more per annum from just direct exposures - i.e.excluding indirect exposure (from rice and other foods) and excluding morbidity.Notwithstanding 1000s of papers published on arsenic (hydro)(bio)geochemistry,there remain a number of key outstanding questions to be addressed in relation to arsenic geoscience - these include questions related to:(i) the role of human activities - irrigation,agriculture and other land uses - on arsenic mobilisation in groundwaters;(ii) the specific sources,nature and role of organics,minerals and microbial communities involved in arsenic mobilisation;(iii) the relationship to microscopic to macroscopic scale geological (including tectonic) and evolution processes;(iv) unravelling the over-printing of multiple processes in complex highly heterogeneous aquifer systems and (v) using increasing understanding of the controls of arsenic mobility in groundwaters systems to informing improved locally-relevant remediation and mitigation approaches.This article further summarises how the 9 further papers in this Special Issue address some of these questions through the use of chemical and/or isotopic tracers.
基金supported by a grants from the National Program on Key Basic Research Project(973 Program),No.2014CB542200the Innovative Research Team by the Ministry of Education,No.IRT1201+1 种基金the National Natural Science Foundation of China,No.31271284,31171150,81171146,30971526,31040043,31371210,81372044,31471144the Beijing Municipal Natural Science Foundation of China,No.7142164
文摘The purpose of this study was to investigate the effect of four fluorescent dyes, True Blue(TB), Fluoro-Gold(FG), Fluoro-Ruby(FR), and 1,1′-dioctadecyl-3,3,3′,3′-tetramethylindocarbocyanine perchlorate(Di I), in retrograde tracing of rat spinal motor neurons. We transected the muscle branch of the rat femoral nerve and applied each tracer to the proximal stump in single labeling experiments, or combinations of tracers(FG-Di I and TB-Di I) in double labeling experiments. In the single labeling experiments, significantly fewer labeled motor neurons were observed after FR labeling than after TB, FG, or Di I, 3 days after tracer application. By 1 week, there were no significant differences in the number of labeled neurons between the four groups. In the double-labeling experiment, the number of double-labeled neurons in the FG-Di I group was not significantly different from that in the TB-Di I group 1 week after tracer application. Our findings indicate that TB, FG, and Di I have similar labeling efficacies in the retrograde labeling of spinal motor neurons in the rat femoral nerve when used alone. Furthermore, combinations of Di I and TB or FG are similarly effective. Therefore, of the dyes studied, TB, FG and Di I, and combinations of Di I with TB or FG, are the most suitable for retrograde labeling studies of motor neurons in the rat femoral nerve.
文摘Non-invasive cardiac imaging has explored enormous advances in the last few decades.In particular,hybrid imaging represents the fusion of information from multiple imaging modalities,allowing to provide a more comprehensive dataset compared to traditional imaging techniques in patients with cardiovascular diseases.The complementary anatomical,functional and molecular information provided by hybrid systems are able to simplify the evaluation procedure of various pathologies in a routine clinical setting.The diagnostic capability of hybrid imaging modalities can be further enhanced by introducing novel and specific imaging biomarkers.The aim of this review is to cover the most recent advancements in radiotracers development for SPECT/CT,PET/CT,and PET/MRI for cardiovascular diseases.
文摘The Aburrá Valley region in Colombia, with Medellín as its main city, is an urban centre with about three million people. An investigation was carried out to deter-mine a set of baseline concentrations for VOC compounds associated with diesel fuel and gasoline, as vehicular emission tracers in the region. The VOC measurement campaigns, based on TENAX tube sampling and analysis according to TO-17 EPA method, were done in areas of low and high vehicular flow as well as on-board measurements covering major Medellín road networks during 24 hours. The results showed that there was a relation between VOCs concentrations and vehicular activi-ty. The diesel fuel sulfur content was also found as an important factor on VOC hy-drocarbon formation.
基金financially supported by the National High-Tech Research and Development Program of China(863 Program),No.2012AA020502the National Natural Science Foundation of China,No.81100939 and 81130080+2 种基金the Collegiate Natural Science Foundation of Jiangsu Province,No.10KJB310009the Innovation Program for Collegiate Postgraduates of Jiangsu Province,No.CXZZ12_0872the Qinglan Project of Jiangsu Province
文摘Fluorescent neuronal tracers should not be toxic to the nervous system when used in long-term labeling. Previous studies have addressed tracer toxicity, but whether tracers injected into an intact nerve result in functional impairment remains to be elucidated. In the present study, we examined the functions of motor, sensory and autonomic nerves following the application of 5% Fluoro-Gold, 4% True Blue and 10% Fluoro-Ruby (5 pL) to rat tibial nerves via pressure injection. A set of evaluation methods including walking track analysis, plantar test and laser Doppler perfusion imaging was used to determine the action of the fluorescent neuronal tracers. Additionally, nerve pathology and ratio of muscle wet weight were also observed. Results showed that injection of Fluoro-Gold significantly resulted in loss of motor nerve function, lower plantar sensibility, increasing blood flow volume and higher neurogenic vasodilatation. Myelinated nerve fiber degeneration, unclear boundaries in nerve fibers and high retrograde labeling efficacy were observed in the Fluoro-Gold group. The True Blue group also showed obvious neurogenic vasodilatation, but less severe loss of motor function and degeneration, and fewer labeled motor neurons were found compared with the Fluoro-Gold group. No anomalies of motor and sensory nerve function and no myelinated nerve fiber degeneration were observed in the Fluoro-Ruby group. Experimental findings indicate that Fluoro-Gold tracing could lead to significant functional impairment of motor, sensory and autonomic nerves, while functional impairment was less severe following True Blue tracing. Fluoro-Ruby injection appears to have no effect on neurological function.
文摘Rare earth elements (REE) were used to study the temporal and spatial processes of soil erosion from different depths and sections of a slope. Two simulated rainfall events were applied to a prepared plot with a slope of 22°. The total runoff and sediment yield were collected every minute during the rainfall events. During the first twenty minutes of the first rainfall event, the average rate of rill erosion and the accumulated sediment yield due to rill erosion was 0.5 and 0.3 times higher than for sheet erosion. During this time, most of the erosion occurred on the lower one third of the plot. After 20 min, rill erosion became the dominant process on the slope. The average acceleration in the rate of rill erosion, the rate of rill erosion and the accumulated sediment yield due to rill erosion were 42, 6 and 4 times higher than that of sheet erosion, respectively. During the first 35 minutes of the second rainfall event, the average acceleration in the rate of rill erosion was 6~9 times higher than that of sheet erosion. Afterwards, the slope became nearly stable with little change in either rill or sheet erosion rates. Initially, most of the rill erosion occurred in the lower third of the slope but later the preexisting rillhead in the middle section of the slope became reactivated and erosion in this section of the slope increased rapidly. These results indicate that REE tracer technology is a valuable tool for quantifying spatial and temporal changes in erosion from a soil slope.
基金This work was supported by the Key Laboratory of Biomedical Engineering of Hainan Province under Opening Foundation 2022001.
文摘Glial cells play an essential part in the neuron system.They can not only serve as structural blocks in the human brain but also participate in many biological processes.Extensive studies have shown that astrocytes and microglia play an important role in neurodegenerative diseases,such as Alzheimer's disease,Parkinson's disease,Huntington's disease,as well as glioma,epilepsy,ischemic stroke,and infections.Positron emission tomography is a functional imaging technique providing molecular-level information before anatomic changes are visible and has been widely used in many above-mentioned diseases.In this review,we focus on the positron emission tomography tracers used in pathologies related to glial cells,such as glioma,Alzheimer's disease,and neuroinflammation.
基金supported by the National Natural Science Foundation of China (10872203)the National Basic Research Program(2007AC744701)the CAS Research and Development Program of China (KSCX2-YW-H18)
文摘Direct measurement of slip length is based on the measured fluid velocity near solid boundary. However, previous micro particle image velocimetry/particle tracking velocimetry (microPIV/PTV) measurements have reported surprisingly large measured near-wall velocities of pressure-driven flow in apparent contradiction with the no-slip hy-pothesis and experimental results from other techniques. To better interpret the measured results of the microPIV/PTV, we performed velocity profile measurements near a hy-drophilic wall (z = 0.25-1.5 μm) with two sizes of tracer particles (φ 50 nm and φ200 nm). The experimental results indicate that, at less than 1 μm from the wall, the deviations between the measured velocities and no-slip theoretical values obviously decrease from 93% of φ200 nm particles to 48% of φ50 nm particles. The Boltzmann-like exponential measured particle concentrations near wall were found. Based on the non linear Boltzmann distribution of particle concentration and the effective focus plane thickness, we illustrated the reason of the apparent velocity increase near wall and proposed a method to correct the measured velocity profile. By this method, the deviations between the corrected measured velocities and the no-slip theoretical velocity decrease from 45.8% to 10%, and the measured slip length on hy-drophilic glass is revised from 75 nm to 16 nm. These results indicated that the particle size and the biased particle concentration distribution can significantly affect near wall velocity measurement via microPIV/PTV, and result in larger measured velocity and slip length close to wall.
文摘Rare earth element(REE) tracer method was used to study sheet erosion changing to rill erosion on slope land. By placing different REE on different soil depth across a slope in an indoor plot, two simulated rainfalls were applied to study the change of erosion type and the rill erosion process. The results indicate that the main erosion type is sheet erosion at the beginning of the rainfalls, and serious erosion happens after rill erosion appears. Accumulated sheet and rill erosion amount increases with the rainfalls time. The percentage of sheet erosion amount decreases and rill erosion percentage increases with time. At the end of the rainfalls, the total rill erosion amounts are 4.3 and 5 times more than sheet erosion. In this paper, a new REE tracer method was used to quantitatively distinguish sheet and rill erosion amount. The new REE tracer method should be useful to future studying of erosion processes on slope lands.
基金supported by the College of Petroleum Engineering and Geosciences,King Fahd University of Petroleum and Minerals.
文摘We report the use of CaTiO_(3):Pr^(3+)multiband persistent luminescent nanoparticles,which can simultaneously emit red(610 nm),near-infrared(893 nm),and short-wave infrared(1040 nm)photoluminescence and persistent luminescence,as the tracer nanoagents for water tracer sensing.By using a spectrofluorometer,an Si charge-coupled device(CCD)camera and an InGaAs array camera as the detection tools,we evaluated the sensing capabilities of the three emission bands of CaTiO_(3):Pr^(3+)nanoparticles in brine water solutions and crude oil/brine water emulsions in both photoluminescence mode and persistent luminescence mode.Among these different detection combinations,the persistent luminescence-based Si CCD camera imaging exhibits the best sensing performance with the detection limits being at a single-digit ppb level for the 610 and 893 nm bands and about 100–200 ppb for the 1040 nm band in both water solutions and crude oil/water emulsions,while the photoluminescencebased Si CCD camera imaging has a much higher detection limit of~10 ppm in water solutions and of~200 ppm in oil/water emulsions.The persistent luminescence-based InGaAs array camera imaging to the 1040 nm band has the worst performance with the detection limits higher than 200 ppm for both solutions.The sensing performances of the spectrofluorometer to photoluminescence signals and persistent luminescence signals in the two solutions are about the same,with the detection limits being around 100–200 ppm.
基金the China Postdoctoral Science Foundation,No.2022M712265.
文摘The increasing popularity of endoscopic submucosal dissection(ESD)as a treatment for early gastric cancer has highlighted the importance of quality assessment in achieving curative resections.This article emphasizes the significance of evaluating ESD quality,not only for curative cases but also for non-curative ones.Postoperative assessment relies on the endoscopic curability(eCura)classification,but management strategies for eCuraC-1 tumour with a positive horizontal margin are unclear.Current research primarily focuses on comparing additional surgical procedures in high-risk patients,while studies specifically targeting eCuraC-1 patients are limited.Exploring management strategies and follow-up outcomes for such cases could provide valuable insights.Furthermore,the application of molecular imaging using near-infrared fluorescent tracers holds promise for precise tumour diagnosis and navigation,potentially impacting the management of early-stage gastric cancer patients.Advancing research in these areas is essential for improving the overall efficacy of endoscopic techniques and refining treatment indications.
文摘Formaldehyde(HCHO) is one of the most important intermediate products of atmospheric photochemical reactions in the troposphere, therefore understanding of HCHO sources is essential for effective ozone control measures. The objective of this work is to distinguish between primary and secondary sources of HCHO. Based on about one month of online measurements in winter in Ziyang,Sichuan, the multi-linear regression analysis of ambient concentrations of HCHO and possible tracers(acetonitrile, propane and peroxyacetyl nitrate) was performed. The results show that during winter in Ziyang, biomass burning contributed an average of 53.2% to ambient HCHO levels, while secondary processes contributed about 30.1%, and vehicular sources accounted for 7.1%.
基金the doctoral dissertation of Nabiyeh Karimi with the financial support of Sari University of Agricultural Sciences and Natural Resources, Iran
文摘Complete and comprehensive information about sediment dynamic and identification of hotspots of sediment production and transport are necessary for understanding the erosion processes and increasing the efficiency of soil and water conservation practices.Numerous studies used the sediment fingerprint techniques to investigate the contribution of different sources in suspended and bed sediment yield of the watersheds.However,the contribution of various land use/land covers in suspended and bed sediment yield for the great Caspian Sea basin is in an aura of ambiguity and the present study was conducted to gather information about an important part of this area in northern Iran,where rangelands are located upstream of Hyrcanian forests and dense agricultural lands are located downstream.The surface soil of different land use/land covers including forest,rangeland,agriculture and streambank lands were sampled in 30 points.Suspended and bed sediments were sampled in the watershed outlet in two high and low water periods.Geochemical characteristics of soil and sediment samples containing 59 elements were measured using ICP-OES GBC Integra.The reliable and suitable tracers from 59 elements were then selected using Range test,Kruskal-Wallis and Discriminant Function Analysis,respectively,in FingerPro package of R software.The results showed that for suspended sediment,streambank and rangeland had the highest contributions of 86.2%and 47.5%,respectively,in two high and low water periods.For bed sediment,in two high and low water periods,rangeland and streambank had the highest contributions of 73.8%and 84.4%,respectively.Land use change and especially human activities such as agriculture,road construction and development of residential areas along the main river riparian zone has led to a significant increase in suspended and bed sediments.
基金jointly supported by the National Natural Science Foundation of China (Grant No.42075153)the Young Scientists Fund of the Earth System Modeling and Prediction Centre (Grant No. CEMC-QNJJ-2022014)。
文摘If an explicit time scheme is used in a numerical model, the size of the integration time step is typically limited by the spatial resolution. This study develops a regular latitude–longitude grid-based global three-dimensional tracer transport model that is computationally stable at large time-step sizes. The tracer model employs a finite-volume flux-form semiLagrangian transport scheme in the horizontal and an adaptively implicit algorithm in the vertical. The horizontal and vertical solvers are coupled via a straightforward operator-splitting technique. Both the finite-volume scheme's onedimensional slope-limiter and the adaptively implicit vertical solver's first-order upwind scheme enforce monotonicity. The tracer model permits a large time-step size and is inherently conservative and monotonic. Idealized advection test cases demonstrate that the three-dimensional transport model performs very well in terms of accuracy, stability, and efficiency. It is possible to use this robust transport model in a global atmospheric dynamical core.