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The main aim of this work was to develop a suitable sorbent for the separation and determination of .sup.226Ra through .sup.133Ba (radio tracer) in water samples using fly ash sorbent. After the modification with KMnO.sub.4 the effects of pH, competing ions, the possibility of elution, and the effect of water volume were tested. As a suitable eluent 6 mol/L HCl was chosen, while the sorbent worked best at pH 6-8. The developed method is advantageous for minimizing the time required for separation, the volume of chemicals used, and the waste generated after separation.

The complex distribution of CO.sub.2 in the upper troposphere and lower stratosphere (UTLS) results from the interplay of different processes and mechanisms. However, in such difficult-to-access regions of the atmosphere our understanding of the CO.sub.2 variability remains limited. Using vertical trace gas profiles derived from measurements with the balloon-based AirCore technique for validation, we investigate the UTLS and stratospheric CO.sub.2 distribution simulated with the ECHAM/MESSy Atmospheric Chemistry (EMAC) global chemistry-climate model. By simulating an artificial, deseasonalised CO.sub.2 tracer, we disentangle the CO.sub.2 seasonal signal from long-term trend and transport contribution. This approach allows us to study the CO.sub.2 seasonal cycle in a unique way in remote areas and on a global scale. Our results show that the tropospheric CO.sub.2 seasonal cycle propagates upwards into the lowermost stratosphere and is most modulated in the extra-tropics between 300-100 hPa, characterised by a 50 % amplitude dampening and a 4-month phase shift in the Northern Hemisphere mid-latitudes. During this propagation the seasonal cycle shape is also tilted, which is associated with the transport barrier related to the strength of the subtropical jet. In the stratosphere, we identified both, a vertical and a horizontal \"tape recorder\" of the CO.sub.2 seasonal cycle. Originating in the tropical tropopause region this imprint is linked to the upwelling and the shallow branch of the Brewer-Dobson-circulation. As the CO.sub.2 seasonal signal carries information about transport processes on different timescales, the newly introduced tracer is a very useful diagnostic tool and would also be a suitable metric for model intercomparisons.

We present an overview of a small-scale tracer migration experiment that was carried out in July 2018 at the Nevada National Security Site. This experiment involved the injection of .sup.133Xe into the bottom of a shallow borehole with multiple sampling intervals. Sampling was then conducted in the injection borehole and in a second borehole located 17 m from the injection site. A simple system for measurement of the .sup.133Xe activity in whole air was utilized onsite. Though many samples were well below MDC, cross-hole tracer transport was observed. Along with experimental results, additional insights gained from numerical modeling are presented.

The mammalian nervous system is comprised of a seemingly infinitely complex network of specialized synaptic connections that coordinate the flow of information through it. The field of connectomics seeks to map the structure that underlies brain function at resolutions that range from the ultrastructural, which examines the organization of individual synapses that impinge upon a neuron, to the macroscopic, which examines gross connectivity between large brain regions. At the mesoscopic level, distant and local connections between neuronal populations are identified, providing insights into circuit-level architecture. Although neural tract tracing techniques have been available to experimental neuroscientists for many decades, considerable methodological advances have been made in the last 20 years due to synergies between the fields of molecular biology, virology, microscopy, computer science and genetics. As a consequence, investigators now enjoy an unprecedented toolbox of reagents that can be directed against selected subpopulations of neurons to identify their efferent and afferent connectomes. Unfortunately, the intersectional nature of this progress presents newcomers to the field with a daunting array of technologies that have emerged from disciplines they may not be familiar with. This review outlines the current state of mesoscale connectomic approaches, from data collection to analysis, written for the novice to this field. A brief history of neuroanatomy is followed by an assessment of the techniques used by contemporary neuroscientists to resolve mesoscale organization, such as conventional and viral tracers, and methods of selecting for sub-populations of neurons. We consider some weaknesses and bottlenecks of the most widely used approaches for the analysis and dissemination of tracing data and explore the trajectories that rapidly developing neuroanatomy technologies are likely to take.

Based on the high-precision isotopic composition and concentration of dissolved inorganic carbon (DIC) in the Bering Sea waters, their scopes and pathways are estimated in the Pacific sector of the Arctic Ocean. Although [delta].sup.13С(DIC) and [DIC] are not classical conservative tracers, these parameters show the presence of both Atlantic and Pacific marine waters similar to the Bering Sea waters in the basin of the East Siberian Sea, which is a zone of active interaction of river and marine waters. The spatial distribution of Pacific and Atlantic and river waters is estimated using a three-component mixing model along two sections of the East Siberian Sea. The Pacific component propagates from east to west approximately to 160° E (probably, more westward) skirting Wrangel Island not only from the north but also probably from the south. The East Siberian Sea contains waters similar to the Bering Sea summer surface waters of the open sea, which are removed to the northern shelf by the circular Bering Sea Current, and to the upper intermediate waters, which can be involved in the zone of the northern sea shelf due to upwelling or active mixing.

Gross primary productivity (GPP), the CO.sub.2 uptake by means of photosynthesis, cannot be measured directly on the ecosystem scale but has to be inferred from proxies or models. One newly emerged proxy is the trace gas carbonyl sulfide (COS). COS diffuses into plant leaves in a fashion very similar to CO.sub.2 but is generally not emitted by plants. Laboratory studies on leaf level gas exchange have shown promising correlations between the leaf relative uptake (LRU) of COS to CO.sub.2 under controlled conditions. However, in situ measurements including daily to seasonal environmental changes are required to test the applicability of COS as a tracer for GPP at larger temporal scales. To this end, we conducted concurrent ecosystem-scale CO.sub.2 and COS flux measurements above an agriculturally managed temperate mountain grassland. We also determined the magnitude and variability of the soil COS exchange, which can affect the LRU on an ecosystem level. The cutting and removal of the grass at the site had a major influence on the soil flux as well as the total exchange of COS. The grassland acted as a major sink for CO.sub.2 and COS during periods of high leaf area. The sink strength decreased after the cuts, and the grassland turned into a net source for CO.sub.2 and COS on an ecosystem level. The soil acted as a small sink for COS when the canopy was undisturbed but also turned into a source after the cuts, which we linked to higher incident radiation hitting the soil surface. However, the soil contribution was not large enough to explain the COS emission on an ecosystem level, hinting at an unknown COS source possibly related to dead plant matter degradation. Over the course of the season, we observed a concurrent decrease in CO.sub.2 and COS uptake on an ecosystem level. With the exception of the short periods after the cuts, the LRU under high-light conditions was rather stable and indicated a high correlation between the COS flux and GPP across the growing season.

Current–voltage (I–V) curve tracers are used for measuring voltage and current in photovoltaic (PV) modules. I–V curves allow identifying certain faults in the photovoltaic module, as well as quantifying the power performance of the device. I–V curve tracers are present in different topologies and configurations, by means of rheostats, capacitive loads, electronic loads, transistors, or by means of DC–DC converters. This article focuses on presenting all these configurations. The paper shows the electrical parameters to which the electronic elements of the equipment are exposed using LTSpice, facilitating the appropriate topology selection. Additionally, a comparison has been included between the different I–V tracers’ topologies, analyzing their advantages and disadvantages, considering different factors such as their flexibility, modularity, cost, precision, speed or rating, as well as the characteristics of the different DC–DC converters.

High-precision measurements of the triple oxygen isotope composition of CO.sub.2 (Î.sup.'17 O) can be used to estimate biosphere-atmosphere exchange of CO.sub.2, the residence time of tropospheric CO.sub.2, and stratosphere-troposphere exchange. In this study, we report measurements of the Î.sup.'17 O(CO.sub.2) from air samples collected during two aircraft-based programmes, CARIBIC and StratoClim. CARIBIC (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container) provided air samples from numerous transcontinental flights in the upper troposphere-lower stratosphere region. StratoClim (Stratospheric and upper tropospheric processes for better climate predictions) conducted intensive campaigns with the high-altitude aircraft M55 Geophysica during the Asian summer monsoon anticyclone (ASMA), providing air samples from altitudes up to 21 km.

Background Fibroblast activation protein-[alpha] (FAP[alpha]) is a marker of activated fibroblasts that can be selectively targeted by an inhibitor (FAPI) and visualised by PET/CT imaging. We evaluated whether the measurement of FAP[alpha] in bronchoalveolar lavage fluids (BALF) and the uptake of FAPI by PET/CT could be used as biomarkers of fibrogenesis. Methods The dynamics of lung uptake of .sup.18F-labeled FAPI ([.sup.18F]FAPI-74) was assessed in the bleomycin mouse model at various time points and using different concentrations of bleomycin by PET/CT. FAP[alpha] was measured in BALFs from these bleomycin-treated and control mice. FAP[alpha] levels were also assessed in BALFs from controls and patients with idiopathic pulmonary fibrosis (IPF). Results Bleomycin-treated mice presented a significantly higher uptake of [.sup.18F]FAPI-74 during lung fibrinogenesis (days 10 and 16 after instillation) compared to control mice. No significant difference was observed at initial inflammatory phase (3 days) and when fibrosis was already established (28 days). [.sup.18F]FAPI-74 tracer was unable to show a dose-response to bleomycin treatment. On the other hand, BALF FAP[alpha] levels were steeply higher in bleomycin-treated mice at day 10 and a significant dose-response effect was observed. Moreover, FAP[alpha] levels were strongly correlated with lung fibrosis as measured by the modified Aschroft histological analysis, hydroxyproline and the percentage of weight loss. Importantly, higher levels of FAP[alpha] were observed in IPF patients where the disease was progressing as compared to stable patients and controls. Moreover, patients with FAP[alpha] BALF levels higher than 192.5 pg/mL presented a higher risk of progression, transplantation or death compared to patients with lower levels. Conclusions Our preclinical data highlight a specific increase of [.sup.18F]FAPI-74 lung uptake during the fibrotic phase of the bleomycin murine model. The measurement of FAP[alpha] in BALF appears to be a promising marker of the fibrotic activity in preclinical models of lung fibrosis and in IPF patients. Further studies are required to confirm the role of FAP[alpha] in BALF as biomarker of IPF activity and assess the relationship between FAP[alpha] levels in BALF and [.sup.18F]FAPI-74 uptake on PET/CT in patients with fibrotic lung disease. Keywords: Idiopathic pulmonary fibrosis, Fibroblast activation protein, Bronchoalveolar lavage, FAPI, PET scan, Biomarker