Iron minerals in soils and sediments play important roles in many biogeochemical processes and therefore influence the cycling of major and trace elements and the fate of pollutants in the environment. However, the kinetics and pathways of Fe mineral recrystallization and transformation processes under environmentally relevant conditions are still elusive. Here, we present a novel approach enabling us to follow the transformations of Fe minerals added to soils or sediments in close spatial association with complex solid matrices including other minerals, organic matter, and microorganisms. Minerals enriched with the stable isotope 57 Fe are mixed with soil or sediment, and changes in Fe speciation are subsequently studied by 57 Fe Mossbauer spectroscopy, which exclusively detects 57 Fe. In this study, 57 Fe-labeled ferrihydrite was synthesized, mixed with four soils differing in chemical and physical properties, and incubated for 12+ weeks under anoxic conditions. Our results reveal that the formation of crystalline Fe(III)(oxyhydr)oxides such as lepidocrocite and goethite was strongly suppressed, and instead formation of a green rust-like phase was observed in all soils. These results contrast those from Fe(II)-catalyzed ferrihydrite transformation experiments, where formation of lepidocrocite, goethite, and/or magnetite often occurs. The presented approach allows control over the composition and crystallinity of the initial Fe mineral, and it can be easily adapted to other experimental setups or Fe minerals. It thus offers great potential for future investigations of Fe mineral transformations in situ under environmentally relevant conditions, in both the laboratory and the field.

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Patient: Female, 65Final Diagnosis: Acquired uterine arteriovenous malformationSymptoms: Vaginal bleedingMedication: —Clinical Procedure: Wait and seeSpecialty: Obstetrics and GynecologyObjective:Rare diseaseBackground:Uterine arteriovenous malformation (AVM) is an uncommon lesion characterized by an abnormal connection between arterial and venous circulation that can be congenital or acquired. Acquired uterine AVMs are generally traumatic and follow delivery, abortion, curettage, or uterine surgery.Case Report:A 45-year-old female who was gravida 1 para 0 presented to our hospital with severe vaginal bleeding. Two weeks before, the patient underwent therapeutic abortion. At admission, a transvaginal ultrasound showed an unclear intrauterine lesion that spread out to the myometrium. Color Doppler evaluation demonstrated an elevated color score. Beta human chorionic gonadotropin (beta-hCG) levels were measured at admission and daily repeated, with a progressive decrease of values up to a negative level. A pelvic magnetic resonance imaging described an area of tubular and tortuous structures involving the myometrium. A computed tomography angiography confirmed the presence of a lesion infiltrating the endometrium and myometrium containing arteriovenous structures with a highly enhanced effect. Despite these findings, the patient was clinically stable. A diagnosis of uterine AVM was made and, after accurate counselling with the patient, she was discharged and underwent “watch and wait” management. After 35 days, the patient had a follow-up ultrasound that showed a complete resolution of the uterine lesion.Conclusions:AVM should be considered in the presence of heavy and sudden vaginal bleeding in a patient with risk factors for acquired AVM. A color Doppler ultrasound scan should be performed as the first approach and an expectant management should be taken into account especially with a patient of childbearing age and hemodynamic instability.

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