RESUMO
Critical metals, identified from supply, demand, imports, and market factors, include rare earth elements (REE), platinum group metals, precious metals, and other valuable metals such as lithium, cobalt, nickel, and uranium. Extraction of metals from U.S. saline aqueous, emphasizing saline, sources is explored as an alternative to hardrock ore mining. Potential aqueous sources include seawater, desalination brines, oil-and-gas produced waters, geothermal aquifers, and acid mine drainage, among others. A feasibility assessment reveals opportunities for recovery of lithium, strontium, magnesium, and several REE from select sources, in quantities significant for U.S. manufacturing and for reduction of U.S. reliance on international supply chains. This is a conservative assessment given that water quality data are lacking for a significant number of critical metals in certain sources. The technology landscape for extraction and recovery of critical metals from aqueous sources is explored, identifying relevant processes along with knowledge gaps. Our analysis indicates that aqueous mining would result in much lower environmental impacts on water, air, and land than ore mining. Preliminary assessments of the economics and energy consumption of recovery show potential for recovery of critical metals.
RESUMO
This study shows thallium (Tl) concentrations in Brassica juncea (Indian mustard) tissue are more than an order of magnitude higher (3830 µg/kg) than that of the substrate (100 µg/kg) and are strongly influenced by the underlying mineralogy; i.e., Tl bioaccessibility depends on the mineral structure: K-feldspar > Mn nodule > hendricksite mica. The majority of Tl for all substrates is contained in edible parts of the plant, i.e., leaves (41% of total Tl, on average) ≥ flower stems (34%) > seed pods (11%) ≈ stems (10%) > flowers (3%). We also show that Tl isotope fractionation induced by B. juncea is substantial, at nearly 10 ε205Tl units, and generates systematic plant-specific patterns. Progressive plant growth strongly fractionates Tl isotopes, discriminating against 205Tl as the plant matures. Thus, 205Tl values are systematically higher in the early formed stem (ε205Tlavg = +2.5) than in plant elements formed later (ε205Tlavg = -2.5 to +0.1), which demonstrates the large degree of translocation and the associated effects during plant growth. This study establishes the potential of Tl isotopes as a new tool for understanding heavy metal (re)distribution during anthropogenic and geologic processes and the utility of such information in environmental and health-related planning and in phytomining or bioprospecting.
Assuntos
Metais Pesados , Poluentes do Solo , Isótopos , Mostardeira , TálioRESUMO
This study assessed the relationship of non-injected illicit drug use and infectious disease seropositivity for human immunodeficiency virus (HIV-1), hepatitis B virus (HBV), hepatitis C virus (HCV), and Syphilis. In a retrospective review of 986 donor charts recovered from 2009 to 2011 at a single tissue bank, the absence of reported non-injected illicit drug use corresponded with seropositivity in 6.61 %, of recovered donors while reported illicit drug use in the medical and social history corresponded with seropositivity in 11.25 %, representing a 70 % increased risk. There was no significant difference noted for overall seropositivity rates between types on noninjected illicit drugs, although donors that used cocaine had a higher incidence of HIV, while marijuana use was associated with a higher rate of HBV, HCV, and syphilis positivity. Toxicology screening results were not an accurate predictor of seropositivity (PPV = 3.77 %; NPV = 91.56 %). Further, the degree of relationship between the donor and the next of kin had no bearing on the veracity of actual drug use when comparing the response of the medical-social history and the toxicology screen.
Assuntos
Drogas Ilícitas , Transtornos Relacionados ao Uso de Substâncias/epidemiologia , Sífilis/epidemiologia , Bancos de Tecidos/estatística & dados numéricos , Doadores de Tecidos/estatística & dados numéricos , Viroses/epidemiologia , Adulto , Florida/epidemiologia , Soropositividade para HIV/epidemiologia , Humanos , Incidência , Pessoa de Meia-Idade , Estudos Retrospectivos , Medição de RiscoRESUMO
⤠Biopsy, staging, preoperative imaging and planning, as well as surgical treatment of soft-tissue sarcomas, are best carried out in specialized sarcoma centers, with the support of a multidisciplinary tumor board.⤠Tumor bed excision is recommended after most unplanned excisions, with a goal of obtaining complete tumor removal with an appropriately wide margin of resection.⤠The surgical resection area tends to be more extensive during tumor bed excision than during primary resection because of the need to resect potential areas of contamination, resulting in the need for more reconstructive procedures (flaps and skin grafts) and wider radiation fields.⤠Unplanned excisions are associated with an increased rate of local recurrence related to residual disease and positive margins after tumor bed excision, a deep location, and certain histologic subtypes, such as malignant peripheral nerve sheath tumor, myxofibrosarcoma, and dermatofibrosarcoma protuberans.⤠While adjuvant radiation therapy has not been found to mitigate the risk of local recurrence in unplanned excisions, it is generally utilized in the treatment of unplanned excisions as it is in the treatment of primary soft-tissue sarcomas.⤠Given the surgical and oncologic sequelae of unplanned excisions, prevention through the diffusion of concepts by means of provider education on how to approach soft-tissue masses, which can be potential soft-tissue sarcomas, is the best strategy.