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BACKGROUND AND OBJECTIVES: Atmospheric zinc corrosion in the Mexico City Metropolitan area has long been attributed mainly to the effect of pollutants such as sulfur dipxide. There are changes in the urban atmosphere's chemical composition due to the implementation of air quality policies focused on reducing the emission of sulfur dipxide and other pollutants. This study's objectives were to estimate and map the contribution of nitric acid on zinc's atmospheric corrosion process METHODS: The impact of nitric acid on zinc is feasible to estimate using a function for a multi-pollutant situation. This function contemplates the sum of two contributions: one of nitric acid and another that includes sulfuric acid and climatic parameters. The multi-pollutant function is suitable to apply in areas without the strong influence of chlorides and tropical and subtropical climates, comparable to the Mexico City Metropolitan area. FINDINGS: The results showed that spatial and temporal estimation of corrosion rates in grams per square meter of zinc was made for 2015-2019, using data modeling in a geographic information system. The maps of corrosion rates allowed us to visualize that, in general, the "southwest" zone has the most significant effects and that the lowest corrosion rates were presented in 2019 as an outcome of the implementation of air quality programs. Furthermore, a contribution of nitric acid up to 32% to the zinc corrosion rate was estimated. CONCLUSION: The construction of corrosion rate maps provides a spatial and temporal estimate that allows visualizing areas where zinc materials are at risk corrosion due to the dispersion of atmospheric pollutants and climatic parameters. Likewise, it can represent a decision-making tool for the implementation of atmospheric corrosion studies of materials. ==========================================================================================COPYRIGHTS©2021 The author(s). This is an open access article distributed under the terms of the Creative Commons Attribution (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, as long as the original authors and source are cited. No permission is required from the authors or the publishers.==========================================================================================

El cobre es un material frecuentemente empleado para la construcción de tuberías, sujeto a la acción de los cloruros, que ocasionan corrosión por picaduras. El presente trabajo busca determinar un posible mecanismo de corrosión por picaduras en el cobre por la acción de los cloruros, apoyándose en la información que ofrecen las técnicas electroquímicas de polarización, espectroscopia de impedancia faradaica y ruido electroquímico.

El cobre es el elemento principal de las aleaciones Cu-Ni recomendadas para aplicaciones marinas. En este trabajo se presenta el comportamiento electroquímico del cobre con los diferentes componentes del agua de mar y el efecto de estos sobre la forma de ataque del cobre. Se observó que los iones cloruro, en unión con los iones sulfato, son los principales causantes del fenómeno de corrosión por picaduras, existiendo, además, una relación significativa entre el potencial crítico de picado (Ep) y la relación (Cl-/SO42-) de tipo parabólico, lo cual pone de manifiesto la importancia del ion sulfato en el fenómeno de corrosión por picaduras como promotor de este tipo de mecanismo.

Se estudia el efecto de los iones Fe2+ en el mecanismo y la cinética de la-deposición catódica del Cu+2+ en soluciones ácidas de CuSO. O.7M a 25°C, con diferentes concentraciones de Fe1+. En base a la determinación de la variación de la densidad de corriente de intercambio con la concentración de Fe2+, se demuestra el efecto inhibidor del Fe + en el proceso de descarga catódica del Cu2+.

The present investigation establishes the basis for future studies in the southeast of México for the improvement of building materials by combining regional organic and inorganic nanoparticles in admixtures to formulate cement mortars with durability potential in structures of concrete. The characterization of the organic extract of Albzia tomentosa by nuclear magnetic resonance (NMR) revealed the presence of epicatechin (tannin related) and sucrose. Calcium zinc hydroxide dihydrate nanoparticles (CZ NPs) showed the highest surface area of 60.7 m 2 g -1 . The electrical resistivity, propagation of ultrasound velocity and water absorption by capillarity properties were individually evaluated for the organic extract, the inorganic nanoparticles and their admixtures in cement mortars, at a curing time of 7, 28 and 96 days with and optimal concentration of 5 mg mL -1 of the added additives. The best results were obtained at 96 days showing slightly but clear improvement of the electrical resistivity (23.40 ± 0.022 kΩ cm, 22.40 ± 0.004 kΩ cm and 22.29 ± 0.013 kΩ cm), propagation of ultrasound velocity (1370 ± 10 m s -1 , 1345 m s -1 ± 6, 1310 ± 9 m s -1 ) and capillary coefficient (0.0044 kg m -2 s -1/2 , 0.0045 kg m -2 s -1/2 and 0.0049 kg m -2 s -1/2 ) properties of the cement mortars with CZ NPs, extraction Albizia solution (EAS) and CZ NPs + EAS respectively when compared to the mortar control (19.91 ± 0.036 kΩ cm, 1266 ± 15 m s -1 and 0.0082 kg m -2 s -1/2 )., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Obesity increases the risk of clinical decompensation in cirrhosis, possibly by increasing portal pressure. Whether weight reduction can be safely achieved through lifestyle (LS) changes (diet and exercise) in overweight/obese patients with cirrhosis, and if weight loss reduces portal pressure in this setting, is unknown. This prospective, multicentric, uncontrolled pilot study enrolled patients with compensated cirrhosis, portal hypertension (hepatic venous pressure gradient [HVPG] ≥6 mm Hg), and body mass index (BMI) ≥26 kg/m 2 in an intensive 16-week LS intervention program (personalized hypocaloric normoproteic diet and 60 min/wk of supervised physical activity). We measured HVPG, body weight (BW) and composition, adipokines, health-related quality of life, and safety data before and after the intervention. Changes in HVPG and BW were predefined as clinically relevant if ≥10% and ≥5%, respectively. Safety and BW were reassessed after 6 months. 60 patients were included and 50 completed the study (56 ± 8 years old; 62% male; nonalcoholic steatohepatitis etiology 24%; BMI 33.3 ± 3.2 kg/m 2 ; Child A 92%; HVPG ≥10 mm Hg, 72%). LS intervention significantly decreased BW (average, -5.0 ± 4.0 kg; P < 0.0001), by ≥5% in 52% and ≥10% in 16%. HVPG also significantly decreased (from 13.9 ± 5.6 to 12.3 ± 5.2 mm Hg; P < 0.0001), by ≥10% in 42% and ≥20% in 24%. A ≥10% BW loss was associated with a greater decrease in HVPG (-23.7 ± 19.9% vs. -8.2 ± 16.6%; P = 0.024). No episodes of clinical decompensation occurred. Weight loss achieved at 16 weeks was maintained at 6 months; Child and Model for End-Stage Liver Disease scores did not change., Conclusion: Sixteen weeks of diet and moderate exercise were safe and reduced BW and portal pressure in overweight/obese patients with cirrhosis and portal hypertension. (Hepatology 2017;65:1293-1305)., (© 2016 by the American Association for the Study of Liver Diseases.)

Unlabelled: Recent studies have shown that liver cirrhosis (LC) behaves as an acquired hypercoagulable state with increased thrombotic risk. This is why anticoagulation therapy (AT) is now frequently used in these patients. Variceal bleeding is a severe complication of LC. It is unknown whether AT may impact the outcome of bleeding in these patients. Fifty-two patients on AT with upper gastrointestinal bleeding (UGIB) were evaluated. Portal vein thrombosis (PVT) and different cardiovascular disorders (CVDs) were the indication for AT in 14 and 38 patients, respectively. Overall, 104 patients with LC and UGIB not under AT matched for severity of LC, age, sex, source of bleeding, and Sequential Organ Failure Assessment (SOFA) score served as controls. UGIB was attributed to portal hypertension (PH) in 99 (63%) patients and peptic/vascular lesions in 57 (37%). Twenty-six (17%) patients experienced 5-day failure; SOFA, source of UGIB, and PVT, but not AT, were independent predictors of 5-day failure. In addition, independent predictors of 6-week mortality, which was observed in 26 (11%) patients, were SOFA, Charlson Comorbidity index, and use of AT for a CVD. There were no differences between patients with/without AT in needs for rescue therapies, intensive care unit admission, transfusions, and hospital stay., Conclusions: Factors that impact the outcome of UGIB in patients under AT are degree of multiorgan failure and comorbidity, but not AT itself., (© 2015 by the American Association for the Study of Liver Diseases.)

Background: Variceal bleeding (VB) is the main cause of death among cirrhotic patients. About 30-50% of early rebleeding is encountered few days after the acute episode of VB. It is necessary to stratify patients with high risk of very early rebleeding (VER) for more aggressive therapies. However, there are few and incompletely understood prognostic models for this purpose., Aims: To determine the risk factors associated with VER after an acute VB. Assessment and comparison of a novel prognostic model generated by Classification and Regression Tree Analysis (CART) with classic-used models (MELD and Child-Pugh [CP])., Patients and Methods: Sixty consecutive cirrhotic patients with acute variceal bleeding. CART analysis, MELD and Child-Pugh scores were performed at admission. Receiver operating characteristic (ROC) curves were constructed to evaluate the predictive performance of the models., Results: Very early rebleeding rate was 13%. Variables associated with VER were: serum albumin (p = 0.027), creatinine (p = 0.021) and transfused blood units in the first 24 hrs (p = 0.05). The area under the ROC for MELD, CHILD-Pugh and CART were 0.46, 0.50 and 0.82, respectively. The value of cut analyzed by CART for the significant variables were: 1) Albumin 2.85 mg/dL, 2) Packed red cells 2 units and 3) Creatinine 1.65 mg/dL the ABC-ROC., Conclusion: Serum albumin, creatinine and number of transfused blood units were associated with VER. A simple CART algorithm combining these variables allows an accurate predictive assessment of VER after acute variceal bleeding. Key words: cirrhosis, variceal bleeding, esophageal varices, prognosis, portal hypertension.

232 asymptomatic HBsAg carriers were controlled between May/1986 and May/1990. The were detected in our blood bank between 1974 and 1976 or during pregnancy or delivery period after 1981. 23 of 232 (10%) became negative during the follow-up, this happening more frequently in carriers after 5 years of follow-up. Only 2 of 209 carriers with HBsAg were HBeAg positive and 1 of these was also DNA-VHB positive. None of the HBeAg negative carriers showed DNA-VHB; only 5 had increased transaminases. 7 were anti-VHC positive, these individuals experiencing more frequent increases in transaminases. The results of this study suggests that the determination of transaminases, viral activity markers, anti-HD, anti-VHC in HBsAg carriers are enough to identify those with hepatic disease.