RESUMO
Expanded vermiculite was used as an adsorbent to remove ammonia nitrogen from landfill leachate. Bench and pilot-scale adsorption experiments were performed with leachate collected from a closed sanitary landfill located in Curitiba, southern Brazil. At the bench-scale, two different heights of vermiculite and three different flow rates were tested using a fixed-bed column. These tests produced an average uptake capacity of 33.4â mg g-1 for the ammonia nitrogen concentration of 2,560â mg L-1. The Yan model was used to determine the breakthrough and the exhaustion times due to the best fit of the data to this model. At the pilot-scale, the flow rate was determined from the shortest length of the mass transfer zone obtained from bench-scale experiments. Tests were performed using one stainless-steel column filled with 26.2â kg of expanded vermiculite, which resulted in a bed height of 1.6â m. A leachate flow rate of approximately 350â L d-1 was applied to achieve the required contact time of 8.3â h. At this scale, an average uptake capacity of 18.1â mg g-1 was obtained for the ammonia nitrogen concentration of 1,193â mg L-1. It is worth mentioning that the flow rate and the concentration of the adsorbate in the feeding solution are fundamental to improve the operational time of the fixed-bed column. The main goal of this research was the determination of operating conditions to scale-up the adsorption process of ammonia nitrogen onto expanded vermiculite. The contact time was a key parameter to reach this goal.
Assuntos
Amônia , Poluentes Químicos da Água , Adsorção , Silicatos de Alumínio , Poluentes Químicos da Água/análise , Nitrogênio/análiseRESUMO
BACKGROUND: Animal pollination is an important ecosystem function and service, ensuring both the integrity of natural systems and human well-being. Although many knowledge shortfalls remain, some high-quality data sets on biological interactions are now available. The development and adoption of standards for biodiversity data and metadata has promoted great advances in biological data sharing and aggregation, supporting large-scale studies and science-based public policies. However, these standards are currently not suitable to fully support interaction data sharing. RESULTS: Here we present a vocabulary of terms and a data model for sharing plant-pollinator interactions data based on the Darwin Core standard. The vocabulary introduces 48 new terms targeting several aspects of plant-pollinator interactions and can be used to capture information from different approaches and scales. Additionally, we provide solutions for data serialization using RDF, XML, and DwC-Archives and recommendations of existing controlled vocabularies for some of the terms. Our contribution supports open access to standardized data on plant-pollinator interactions. CONCLUSIONS: The adoption of the vocabulary would facilitate data sharing to support studies ranging from the spatial and temporal distribution of interactions to the taxonomic, phenological, functional, and phylogenetic aspects of plant-pollinator interactions. We expect to fill data and knowledge gaps, thus further enabling scientific research on the ecology and evolution of plant-pollinator communities, biodiversity conservation, ecosystem services, and the development of public policies. The proposed data model is flexible and can be adapted for sharing other types of interactions data by developing discipline-specific vocabularies of terms.
Assuntos
Ecossistema , Polinização , Animais , Biodiversidade , Filogenia , Padrões de ReferênciaRESUMO
PURPOSE: Although chemoradiation therapy (CRT) with cisplatin remains the standard treatment of patients with locally advanced cervical cancer (LACC), 40% of patients present with disease recurrence. Additional treatment strategies are required to improve outcomes. We conducted a trial to evaluate the efficacy and safety of neoadjuvant chemotherapy (NAC) with cisplatin and gemcitabine followed by CRT. METHODS: In this phase II trial, patients with LACC (International Federation of Gynecology and Obstetrics stage IIB to IVA or with positive lymph nodes) were randomly assigned to three cycles of NAC with cisplatin and gemcitabine followed by standard CRT with weekly cisplatin plus pelvic radiotherapy or to standard CRT alone. The primary end point was 3-year progression-free survival (PFS). Secondary end points were response rate, 3-year locoregional control, 3-year overall survival (OS), safety, and quality of life. RESULTS: From 107 patients enrolled in the trial, 55 were randomly assigned to the NAC arm and 52 to the CRT-alone arm. The majority of patients had squamous cell carcinoma (87.8%). After a median follow-up of 31.7 months, NAC was associated with an inferior PFS, with 3-year PFS rates of 40.9% v 60.4% in the CRT arm (hazard ratio, 1.84; 95% CI, 1.04 to 3.26; P = .033). NAC also was associated with a lower OS (3-year OS rate, 60.7% v 86.8%; hazard ratio, 2.79; 95% CI, 1.29 to 6.01; P = .006). After treatment completion, complete response rates were 56.3% in the NAC arm and 80.3% in the CRT arm (P = .008). Toxicities were similar in both arms, with the exception of hypomagnesemia and neuropathy being more common with NAC. CONCLUSION: This study shows that the addition of NAC consisting of cisplatin and gemcitabine to standard CRT is not superior and is possibly inferior to CRT alone for the treatment of LACC.