Letteratura scientifica selezionata sul tema "Gadolinium Anomaly"

Rare earth elements (REEs), known as “industrial vitamins”, are widely used in medical treatment, industry, agriculture, etc. However, with the increasing demand for REEs, excess REEs, such as gadolinium (Gd), are considered micropollutants in the environment. In this paper, the distributions of dissolved REEs were analyzed in three small streams, in order to determine the extent and occurrence of Gd anomalies. The shale-normalized REE patterns in the three streams were less smooth with heavy REEs higher than light REEs, for a weak reaction of the heavy REE complexes. A negative Ce (cerium) anomaly and positive samarium (Sm) and europium (Eu) anomalies were observed in the three streams and the negative Ce anomaly was affected by the pH of the alkaline rivers. However, a positive Gd anomaly was found in only a typical urban small stream, Jinzhong. With a population of approximately 60,000, Jinzhong runs by a hospital and through wastewater treatment plants (WWTPs). The concentrations of Gd in Jinzhong ranged from 1.54 to 86.65 ng/L with high anthropogenic Gd proportions (63.64%–98.07%). Anthropogenic Gd showed significant seasonal variations and distinct spatial disparities from upstream to downstream, and it was associated with certain ions such as Cl−. Anthropogenic Gd could be attributed to gadopentetic acid (Gd-DTPA), which is used in magnetic resonance imaging (MRI) in hospitals. This type of Gd was shown to be correlated with municipal wastewater. Due to the high stability and low particulate reactivity in water, anthropogenic Gd has great potential to serve as a tracer to prove the presence of medical wastewater.

Abstract. The inlet of diverted river water into agricultural areas or nature reserves is a frequently applied management strategy to prevent fresh water shortage. However, the inlet water might have negative consequences for water quality in the receiving water bodies. This study aimed to obtain a spatial image of the inlet water propagation into a hydrological complex polder area. We used anthropogenic gadolinium (Gd-anomaly) as a tracer for diverted river water. A clear reduction in the river water contribution was found from very dry conditions on 5 August 2010 to very wet conditions on 22 October. Despite the large inlet water impact on 5 August, the diverted river water did not propagate up into the small agricultural headwater ditches. Gadolinium proved to be an effective tracer for diverted river water in a polder system. We applied our results to upgrade the interpretation of water quality monitoring data and to validate our integrated nutrient transport models.

Abstract BACKGROUND The rarity of Isocitrate Dehydrogenase mutated (mIDH) glioblastomas relative to wild-type IDH glioblastomas, as well as their distinct tumor physiology, effectively render them “outliers”. Specialized tools are needed to identify these outliers. OBJECTIVE To carefully craft and apply anomaly detection methods to identify mIDH glioblastoma based on radiomic features derived from magnetic resonance imaging. METHODS T1-post gadolinium images for 188 patients and 138 patients were downloaded from The Cancer Imaging Archive's (TCIA) The Cancer Genome Atlas (TCGA) glioblastoma collection, and from the University of Minnesota Medical Center (UMMC), respectively. Anomaly detection methods were tested on glioblastoma image features for the precision of mIDH detection and compared to standard classification methods. RESULTS Using anomaly detection training methods, we were able to detect IDH mutations from features in noncontrast-enhancing regions in glioblastoma with an average precision of 75.0%, 69.9%, and 69.8% using three different models. Anomaly detection methods consistently outperformed traditional two-class classification methods from 2 unique learning models (67.9%, 67.6%). The disparity in performances could not be overcome through newer, popular models such as neural networks (67.4%). CONCLUSION We employed an anomaly detection strategy in the detection of IDH mutation in glioblastoma using preoperative T1 postcontrast imaging. We show these methods outperform traditional two-class classification in the setting of dataset imbalances inherent to IDH mutation prevalence in glioblastoma. We validate our results using an external dataset and highlight new possible avenues for radiogenomic rare event prediction in glioblastoma and beyond.

Gadolinium–terbium fumarate heptahydrate crystals were grown in silica gel by using single gel diffusion technique. The crystals were characterized by different physico-chemical techniques of characterization. Powder X-ray diffraction results showed that the grown material is purely crystalline in nature. Elemental analyses suggested the chemical formula of the compound to be Gd Tb [Formula: see text]. Energy dispersive X-ray analysis confirmed the presence of Gd and Tb in the title compound. The dielectric and conductivity studies of the grown compound were carried as function of frequency of applied field and the temperature. The grown material showed a dielectric anomaly which was correlated with its thermal behavior. The ac conductivity of the material showed Jonscher's power law behavior: [Formula: see text], with a temperature-dependent power exponent [Formula: see text]. The conductivity was found to be a function of temperature and frequency.

Abstract. Diverting river water into agricultural areas or nature reserves is a frequently applied management strategy to prevent fresh water shortage. However, the river water might have negative consequences for chemical and ecological water quality in the receiving water bodies. This study aimed to obtain a spatial image of the diverted river water propagation into a hydrologically complex polder area, the polder Quarles van Ufford in The Netherlands. We used anthropogenic gadolinium (Gd-anomaly) as a tracer for river water that was diverted into the polder. A clear reduction in the river water contribution was found between very dry conditions on 5 August 2010 and very wet conditions on 22 October. Despite the large river water impact on 5 August, the diverted river water did not propagate up into the small agricultural headwater ditches. Gadolinium proved to be an effective tracer for diverted river water in a polder system. We applied our results to upgrade the interpretation of water quality monitoring data and to validate an integrated nutrient transport model.

In the course of the studies described in Parts I and II, an unusual result was observed in the case of the structure determination of hydrated gadolinium(III) picrate. Midway through data collection, the monoclinic P 21/c phase underwent a phase modification (X-ray-induced?) to a similar cell more nearly resembling that of the La → Pr structure type recorded previously, with no loss of crystal integrity, and with useful data sets being obtained on both forms. Redetermination of the structure with a fresh sample yielded no reproduction of the anomaly. These results are recorded and discussed, together with an overview of the consequences of the data of Parts I-III in relation to those of other literature in the field.

Les Terres Rares (REE) sont naturellement présentes dans les eaux du fait de l’érosion des roches. Elles sont également employées dans des activités anthropiques (nouvelles technologies, énergies, agriculture et médecine). Ces utilisations en constante augmentation ont fini par perturber le cycle géochimique et biologique des REE et ont mené à l’enrichissement (anomalie positive) de certaines REE dans l’hydrosphère (La, Ce, Sm et Gd). Pour le Gdanth, la pollution provient des stations de traitements des eaux usées conventionnelles (STEU) qui ne sont pas en mesure d'éliminer la forme complexe organique de Gd utilisée dans l'analyse IRM. Quatre ensembles ont donc été étudiés afin de mieux connaître le comportement des REE : le bassin français de la Moselle, le bassin du Danube dans son ensemble, la STEU du Grand Nancy, et la zone de rejet végétalisée (ZRV) en aval de la STEU du Grand Reims. Le long de la Moselle, la présence d'anomalies positives en Gd et un appauvrissement régulier des LREE comparativement aux HREE enrichies sur les spectres de REE sur des substrats de grès/calcaire sont les points les plus caractéristiques. Dans le bassin du Danube, l’anomalie positive en Gd varie de 1,8 à 37,4 dans les eaux de surfaces et jusqu’à 80,8 dans les eaux souterraines, montrant une contamination des puits alluviaux. Au sein de la STEU du Grand Nancy, les flux entrant de Gd ont montré être plus importants en semaine (mardi et mercredi), et aux heures de fin de journée (19h-22h). Les procédés de traitement n’affectent pas le Gdanth, mais augmentent le fractionnement LREE/HREE. Les eaux de la ZRV sont celles qui présentent les plus fortes valeurs d’anomalies positives en Gd (jusqu’à 4500). Il a été démontré que l'ampleur des anomalies Gd dépendait de l'approche méthodologique choisie pour leur calcul. La définition d'une valeur seuil pour identifier la présence d'une anomalie anthropique Gd peut donc dépendre du bassin, et se révéler délicate dans les zones où la pression anthropique est faible
Rare Earths Elements (REEs) are naturally present in water due to the erosion of rocks. They are used in human activities (new technologies, energy, agriculture and medicine). These ever-increasing uses eventually disrupted the geochemical and life cycle of REEs and led to the enrichment (positive anomaly) of some REEs in the hydrosphere (La, Ce, Sm and Gd). For anthropogenic Gd, pollution derives from conventional wastewater treatment plants (WWTPs) which are not able to remove the organic complex form of Gd used in MRI analyses. Four areas were therefore studied in order to better understand the behavior of the REEs: the French basin of the Moselle River, the Danube river basin as a whole, the WWTP of Grand Nancy, and the constructed wetland downstream the WWTP of Grand Reims. Along the Moselle River, the presence of positive Gd anomalies and a regular LREEs depletion/ HREEs enrichment pattern on sandstone/limestone substrates were the most distinctive features. In the Danube basin, the positive Gd anomaly ranged from 1.8 to 37.4 in surface water and up to 80.8 in groundwater, showing contamination of alluvial wells. Within the Greater Nancy STEU, the greatest Gd inflows were observed during weekdays (Tuesday and Wednesday), and at the end of the day (7 p.m. to 10 p.m.). Treatment processes did not affect anthropogenic Gd, but increased LREE/HREE fractionation. The waters of the artificial wetland were those with the highest values of positive Gd anomalies (up to 4500). It was shown that the magnitude of Gd anomalies depended on the methodological approach chosen for their calculation. The choice of a threshold value to identify the presence of an anthropogenic Gd anomaly may therefore be basin dependent and may be tricky in areas where anthropogenic pressure is low