Adsorption Isotherms: Enlightenment of the Phenomenon of Adsorption

Adsorption is a process in which a substance that is in a liquid phase accumulates on a solid surface and is then removed from the liquid phase. An adsorption isotherm describes the equilibrium of adsorption of a substance on a surface at a constant temperature. It represents the amount of material bound to the surface as a function of the material present in the solution. In the adsorption process, the compound to be removed is called the adsorbate and the solid on which the compound is adsorbed is called the adsorbent. The affinity of the adsorbate for the adsorbent is quantified using adsorption isotherms. Adsorption isotherms are mathematical equations that describe the relationship between the amount of adsorbate adsorbed on an adsorbent and the concentration of adsorbate in solution when equilibrium has been reached at constant temperature. Adsorption isotherms are performed by giving a volume-determined solution containing a known amount of adsorbate along with various dosages of the adsorbent. The mixture is held at constant temperature with stirring until it reaches equilibrium. When this is the case, the concentration of the adsorbate in the aqueous phase is measured and the adsorption capacity at equilibrium for each experiment is calculated from the mass balance

Estudio palinológico de la flora urbana de la ciudad de Chihuahua, México

The aim of this study was to provide the first palynological study of Chihuahua City, Mexico, resulting in the development of a graphic reference document about pollen of Gymnosperms and Angiosperms in this zone. Samples of both ornamental and wild plants were included, which were collected on sidewalks, parks, public areas, and suburbs of the studied area. The study included 91 taxa: 15 trees, 10 shrubs and 66 herbs from 37 families and 86 genera. Pollen grains were directly obtained from the stamens and observed with scanning electronic microscope without acetolizing, hydrating or dehydrating. Most of the studied pollen grains had a medium size (60%). The most common ornamentation patterns were echinate (23%) and reticulate (22%). A large percentage of the pollen grains showed elongated apertures: tricolporate (41%) and tricolpate (13%), which coincides with the folding pattern of sunken apertures. Pollen grains of most of the studied species show spheroidal shape in hydrated state (83%), while the most common shape among dehydrated grains is prolate (51%). Three main pollen types were observed; the first type corresponds to the family Asteraceae and the second one to Poaceae. The third type included 10 families and 15 species whose pollen grains have reticulated ornamentation, elongated apertures, prolate shape in its dry state and sunken apertures. It is recognized that the inclusion of more species present in the area is needed.El objetivo de este trabajo fue presentar el primer estudio palinológico de la ciudad de Chihuahua, México, resultando en el desarrollo de un documento gráfico del polen de las gimnospermas y angiospermas de la zona. Se incluyeron muestras tanto de plantas de ornato como silvestres, las cuales fueron colectadas en aceras, parques, áreas públicas y suburbios del área de estudio. El trabajo incluyó 91 especies: 15 árboles, 10 arbustos y 66 herbáceas correspondientes a 37 familias y 86 géneros. Los granos de polen fueron obtenidos directamente de los estambres y observados al microscopio electrónico de barrido sin acetolizar, hidratar o deshidratar. La mayoría de los granos de polen (60%) estuvieron en el rango de tamaño medio. Los patrones de ornamentación más comunes fueron el equinado (23%) y el reticulado (22%). Un gran porcentaje mostró aberturas elongadas: tricolporadas (41%) y tricolpadas (13%), las cuales coinciden con el patrón de plegamiento con aberturas hundidas. Los granos de polen de la mayoría de las especies estudiadas presentan forma esferoidal en su estado hidratado (83%), mientras que la más común entre los granos deshidratados es la prolata (51%). Se observaron tres principales tipos polínicos; el primero corresponde a la familia Asteraceae, el segundo a Poaceae, mientras que el tercero incluye a 10 familias y 15 especies cuyos granos de polen presentan ornamentación reticulada, aberturas elongadas, forma prolata en su estado seco y aberturas hundidas. Se reconoce la necesidad de incluir a futuro más especies presentes en el área

Effect of Acid Treatment on the Physicochemical Characteristics and Sorption Capacity of a Natural Zeolite

Mining is a very important industry for the development of emerging economies; however, it generates a large number of environmental externalities such as acid mine drainages; these have acid pH values and high heavy metal content. Although there are several methods for the elimination of metals in different solutions, they require a large economic investment. Recently, the use of adsorbent materials for the removal of heavy metals in acid drains such as agricultural by-products and natural zeolites has been developed as a cheaper alternative. In spite of the environmental benefits of using natural zeolites as adsorbent, one of the disadvantages is dealumination, which to a great extent could depend on the geological origin of the mineral that shapes some of its characteristics. This study characterized chemical and physical properties of natural and modified zeolites using various techniques, such as X-ray diffraction (XRD), N2 adsorption- desorption, inductively coupled plasma − optical emission spectroscopy (ICP-OES), and SEM-EDS to determine the effect of an acid treatment on the physical and chemical characteristics of a natural zeolite, correlating these with their sorption capacity. When giving acid treatment to a zeolite there are no significant changes in the crystal structure, the Si/Al ratio indicates a dealumination of the structure but with minimal changes, the surface area and density of the micropores increased considerably. A significant increase in the capacity of copper adsorption was registered. According to XRD, no significant changes occur to the structures. Keywords: Dealumination; aluminosilicates; AMD; acid treatment; metal removal. DOI: 10.7176/JEES/10-9-05 Publication date:September 30th 202

Agronegocios y Ganadería Sostenible

Desde una visión sustentable, se despliega esta obra que lleva por nombre Agronegocios y Ganadería Sostenible, compila catorce trabajos de cinco países de América Latina: México, Colombia, Argentina Venezuela y Perú, en cuatro secciones centrales. Se destaca, el trabajo conjunto entre la Universidad Nacional Toribio Rodríguez de Mendoza de Amazonas (UNTRM), Perú, y la Universidad del Zulia, Venezuela. Los esfuerzos de ambas instituciones han permitido desde el Instituto de Investigación en Ganadería y Biotecnología (IGBI), el Instituto de Investigación en Negocios Agropecuarios (INNA) de la Facultad de Ingeniería Zootecnista, Agronegocios y Biotecnología (FIZAB), con el apoyo financiero del Proyecto “Mejoramiento de tecnologías para el incremento de núcleos de ganado bovino de alto valor genético en las estaciones experimentales ganaderas de la Universidad Nacional Toribio Rodríguez de Mendoza, sede Chachapoyas, provincia Chachapoyas, región Amazonas” (PROTEGAN – SNIP N°346922), y el apoyo y aval académico e institucional de la Facultad de Ciencias Económicas y Sociales, Centro de Estudios de la Empresa de la Universidad del Zulia, Venezuela, esta obra de gran alcance para Latinoamérica. Engloba capítulos para disertar sobre la gestión de los Agronegocios, en cuanto a nuevas formas de organización de la producción agraria, ante la complejidad de sus operaciones y los diferentes tipos de organizaciones que se gestan con intereses y propósitos diversos. De igual forma, se discute sobre la gestión por procesos en sistemas ganaderos, siendo propicio asumir, procesos medulares o de apoyo para la comprensión plena de estos sistemas productivos, y orientar decisiones sobre desempeño y despliegue de valor en las cadenas pecuarias. La construcción, de-construcción y re-construcción de conocimientos, se hace visible ante la presencia de modelos emergentes y alternativas sustentables, que soportan el desarrollo y conservación de los ecosistemas productivos estudiados.Libr

Utilization of mechanical power and associations with clinical outcomes in brain injured patients: a secondary analysis of the extubation strategies in neuro-intensive care unit patients and associations with outcome (ENIO) trial

Background: There is insufficient evidence to guide ventilatory targets in acute brain injury (ABI). Recent studies have shown associations between mechanical power (MP) and mortality in critical care populations. We aimed to describe MP in ventilated patients with ABI, and evaluate associations between MP and clinical outcomes. Methods: In this preplanned, secondary analysis of a prospective, multi-center, observational cohort study (ENIO, NCT03400904), we included adult patients with ABI (Glasgow Coma Scale ≤ 12 before intubation) who required mechanical ventilation (MV) ≥ 24 h. Using multivariable log binomial regressions, we separately assessed associations between MP on hospital day (HD)1, HD3, HD7 and clinical outcomes: hospital mortality, need for reintubation, tracheostomy placement, and development of acute respiratory distress syndrome (ARDS). Results: We included 1217 patients (mean age 51.2 years [SD 18.1], 66% male, mean body mass index [BMI] 26.3 [SD 5.18]) hospitalized at 62 intensive care units in 18 countries. Hospital mortality was 11% (n = 139), 44% (n = 536) were extubated by HD7 of which 20% (107/536) required reintubation, 28% (n = 340) underwent tracheostomy placement, and 9% (n = 114) developed ARDS. The median MP on HD1, HD3, and HD7 was 11.9 J/min [IQR 9.2-15.1], 13 J/min [IQR 10-17], and 14 J/min [IQR 11-20], respectively. MP was overall higher in patients with ARDS, especially those with higher ARDS severity. After controlling for same-day pressure of arterial oxygen/fraction of inspired oxygen (P/F ratio), BMI, and neurological severity, MP at HD1, HD3, and HD7 was independently associated with hospital mortality, reintubation and tracheostomy placement. The adjusted relative risk (aRR) was greater at higher MP, and strongest for: mortality on HD1 (compared to the HD1 median MP 11.9 J/min, aRR at 17 J/min was 1.22, 95% CI 1.14-1.30) and HD3 (1.38, 95% CI 1.23-1.53), reintubation on HD1 (1.64; 95% CI 1.57-1.72), and tracheostomy on HD7 (1.53; 95%CI 1.18-1.99). MP was associated with the development of moderate-severe ARDS on HD1 (2.07; 95% CI 1.56-2.78) and HD3 (1.76; 95% CI 1.41-2.22). Conclusions: Exposure to high MP during the first week of MV is associated with poor clinical outcomes in ABI, independent of P/F ratio and neurological severity. Potential benefits of optimizing ventilator settings to limit MP warrant further investigation

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

EVALUACIÓN DE PARTICULAS ATMOSFÉRICAS PST Y PM10 EN LA CIUDAD DE CHIHUAHUA, MÉXICO: NIVELES DE CONCENTRACIÓN, COMPOSICIÓN ELEMENTAL E IDENTIFICACIÓN DE FUENTES EMISORAS.

Doctoral thesi

Beneficio de la intervención coronaria percutánea, en pacientes rescatados de paro cardiorrespiratorio

Objetivo.Determinar el beneficio del ICP en pacientes recuperados de un PCR en el Instituto de Cardiología y Cirugía Cardiovascular de la Habana Cuba Método:Se realizó un estudio descriptivo, longitudinal retrospectivo, que incluyó 32 pacientes con diagnóstico de PCR recuperada atendidos en el Instituto de Cardiología y Cirugía Cardiovascular durante el periodo comprendido entre enero de 2011 hasta diciembre de 2016.Resultados: La mayoría de los pacientes recuperados de PCR,  el shock cardiogénico fue la principal indicación de coronariografía (40,0%), la que se realizó con mayor frecuencia en las primeras 24-48 horas (40,0%). La realización de coronariografía o ICP no se relacionó con el estado al egreso de los pacientes recuperados de PCR.Conclusiones: Se concluye que los pacientes recuperados de PCR exhiben un elevado riesgo cardiovascular aterosclerótico, con una elevada prevalencia de enfermedad coronaria significativa

Beneficio de la intervención coronaria percutánea, en pacientes rescatados de paro cardiorrespiratorio

Objetivo.Determinar el beneficio del ICP en pacientes recuperados de un PCR en el Instituto de Cardiología y Cirugía Cardiovascular de la Habana Cuba Método:Se realizó un estudio descriptivo, longitudinal retrospectivo, que incluyó 32 pacientes con diagnóstico de PCR recuperada atendidos en el Instituto de Cardiología y Cirugía Cardiovascular durante el periodo comprendido entre enero de 2011 hasta diciembre de 2016.Resultados: La mayoría de los pacientes recuperados de PCR,  el shock cardiogénico fue la principal indicación de coronariografía (40,0%), la que se realizó con mayor frecuencia en las primeras 24-48 horas (40,0%). La realización de coronariografía o ICP no se relacionó con el estado al egreso de los pacientes recuperados de PCR.Conclusiones: Se concluye que los pacientes recuperados de PCR exhiben un elevado riesgo cardiovascular aterosclerótico, con una elevada prevalencia de enfermedad coronaria significativa