Avaliação da qualidade da água dos reservatórios localizados nas bacias hidrográficas dos rios Piauí -Real, utilizando o índice de qualidade da água (IQA)Evaluation of the water quality of the reservoirs located in the Piauí -Real river basins, using the water quality index (IQA) A água do reservatório AG foi classificada como "Ruim" e a do reservatório JB como "Boa". Para os reservatórios TB e DM a qualidade da água variou de "Aceitável" para "Boa" em função do período de amostragem. Os parâmetros que mais impactaram sobre a qualidade da água foram DBO5, OD, COL e STD, e devem estar associados, principalmente, ao aporte de despejos sanitários e a processos de salinização. In this work the multiplicative IQA, developed by NSF (National Sanitation Foundation) and adapted in Brazil by the São Paulo Environmental Sanitation Technology Company (CETESB), was used to evaluate the water quality of the reservoirs Dionísio Machado (DM), Taboca (TB), Amargosa (AG) and Jabiberi (JB), located in the South Central region of the State of Sergipe. The DM and TB reservoirs are located in the Piauí river basin, and the AG and JB in the Real river basin. Surface water samples were collected from June/2013 to August/2014, comprising two rainy periods and one dry period. In each sample the following parameters were determined: pH, turbidity (TUR), dissolved oxygen (OD), biochemical oxygen demand (BOD5), total dissolved solids (STD), total phosphorus (Pt), nitrate (NO3), thermotolerant coliforms (COL) and water temperature (T, measured in the field). Principal Component Analysis (PCA) was used with an auxiliary tool to solve the limitation of the IQA, in relation to the STD values above 500 mg L -1 . The water in the AG reservoir was classified as "Bad" and the water in the JB reservoir was "Good". For the TB and DM reservoirs the water quality ranged from "Acceptable" to "Good" depending on the sampling period. The parameters that most affected the water quality were DBO5, OD, COL and STD, and should be associated mainly with the contribution of sanitary waste and salinization processes.R

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Gastric ulcer (GU), a common type of peptic ulcer, results from an imbalance in the action of protective and aggressive agents. Gastroprotective mechanisms are mucus layer, gastric epithelium, gastric blood flow, gastric neurons, mucosal repair capacity, and immune system. Thus, the aim of this chapter was to provide an update on gastroprotective mechanisms. It was carried out through searches in PubMed covering the years 2016–2021 using several keywords. This survey resulted in 428 articles, of which 110 were cited in this chapter. It was reviewed the status of gastroprotective mechanisms and highlighted that mucins can act as a filter; gastric epithelial defenses are composed of the cell barrier, stem cells, and sensors on the mucosal surface; nitric oxide (NO) and hydrogen sulfide (H2S) act for gastric blood flow homeostasis (GBF); the main effector neurons in the gastric mucosa are cholinergic, nitrergic and VIPergic, and oxytocin can activate neurons; repair of the gastric mucosa requires complex biological responses; the immune system regulates the entry of antigens and pathogens. The main knowledge about gastroprotective mechanisms remains unchanged. However, we conclude that there has been progressing in this area.