Nanocellulose-Block Copolymer Films for the Removal of Emerging Organic Contaminants from Aqueous Solutions.

The prevalence of emerging organic contaminants (EOCs) in ground and surface water has sparked the search for more effective methods to remove EOCs from the environment. In pursuit of a solution for this environmental concern, herein we present the development of reusable films based on cellulose nanofibers (CNFs) and the block copolymer, poly(4-vinylpyridine-b-ethylene oxide) (P4VP-PEO) to adsorb sulfamethoxazole (SMX) as an EOC model compound. We hypothesize that the adsorption of SMX was achieved mainly by π-π interactions between the pyridine functionalities of the block copolymer and the electron deficient phenyl group of the SMX. Preceding preparation of the films, CNFs were modified with the alkoxysilane trimethoxy(2-phenylethyl)silane (TMPES) to increase their stability in aqueous solution. After the addition of P4VP-PEO, the process was completed by filtration followed by oven-drying. XPS and FTIR were employed to confirm the addition of TMPES and P4VP-PEO, respectively. Adsorption batch experiments were performed in aqueous solutions of SMX at a neutral pH, obtaining adsorptions of up to 0.014 mmol/g in a moderate time of 60 min. For the reusability tests, films were immersed in ethanol 95 wt.% to elude the adsorbed SMX, rinsed with deionized (DI) water, and dried at room temperature to be reused in a new adsorption cycle. We found that this new composite material could be reused several times with negligible loss of adsorption capacity. The films presented have been shown to be of substantial importance for water remediation as they find direct application in the adsorption of electron deficient aromatic compounds and are reusable.

Cellulose Acetate/P4VP-b-PEO Membranes for the Adsorption of Electron-Deficient Pharmaceutical Compounds.

The prevalence of pharmaceutical compounds in surface and groundwater presents a rising threat to human health. As such, the search for novel materials that serve to avoid their release into the environment or for the remediation once in the water effluent is of utmost importance. The present work describes the fabrication of a cellulose acetate membrane modified with the block copolymer poly(4-vinylpyridine-b-ethylene oxide) (P4VP-b-PEO) crafted for the specific targeting and adsorption of electron-deficient pharmaceuticals (EDPs). The EDPs under study were sulfamethoxazole, sulfadiazine, and omeprazole. The results as part of this work present a thorough characterization of the prepared membranes by FTIR, contact angle measurement, and SEM images. Moreover, results show that the adsorptive character of the membrane correlates with the relative electron deficiency and spatial orientation of the contaminant. Interestingly, the addition of nominal 1% P4VP-b-PEO to the cellulose matrix helps to increase the adsorption efficiency of the membranes by at least 2-fold in most cases. For the compounds studied, the prepared membrane has a higher efficiency toward omeprazole followed by sulfamethoxazole and sulfadiazine. This work may serve to inspire the design and fabrication of selective soft materials for the adsorption and remediation of contaminants of emerging concern.

Examining the Use of Nanocellulose Composites for the Sorption of Contaminants of Emerging Concern: An Experimental and Computational Study.

The occurrence of contaminants of emerging concern (CECs) in water is an environmental issue that must be addressed to avoid damage to ecosystems and human health. Inspired by this current issue, in this work, we fabricated nanocellulose (NC) particles grafted with the block copolymer Jeffamine ED 600 (NC-Jeffamine) capable of adsorbing acetaminophen, sulfamethoxazole, and N,N-diethyl-meta-toluamide (DEET) from aqueous solution by electrostatic interactions. NC-Jeffamine composites were prepared by carboxylation of the NC surface via 2,2,6,6-tetramethyl-1-piperidinyloxy oxidation followed by the covalent attachment of Jeffamine using the N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide/N-hydroxysulfosuccinimide sodium salt reaction. The reaction was followed and confirmed by Fourier transform infrared and conductometric titration. The physical characterization was performed by thermogravimetric analysis, Brunauer-Emmett-Teller analysis, scanning electron microscopy, dynamic light scattering, and Z-potential analysis. This material was used to study the adsorption profile of three CECs in deionized water, namely, acetaminophen, sulfamethoxazole, and DEET. The adsorption isotherms were obtained at pH 3, 7, and 9, where the best adsorption results corresponded to pH 9 because of the uniform dispersion of the adsorbate in solution. A computational study based on the density functional theory determined that the possible interactions of the CECs with the adsorbent material were related to hydrogen bonds and/or van der Waals forces. The calculated binding energies were used as a descriptor to characterize the optimum adsorption site of CECs onto NC-Jeffamine.

Actividad antimicobacteriana de terpenos / Antimycobacterial activity of terpenes

Introducción: La tuberculosis (TB), causada por Mycobacterium tuberculosis es la mayor causa de mortalidad mundial por un único agente patógeno. Asimismo, un gran número de micobacterias no tuberculosas, especialmente M. avium, M. intracellulare y M. chelonae, causan infecciones oportunistas en pacientes con SIDA. Muchos terpenos poseen actividad biológica y se emplean en el tratamiento de diversas enfermedades, razón que los hace fuente de moléculas promisorias. Objetivo: El objetivo del presente estudio fue determinar la actividad antimicobacteriana de 16 terpenos contra M. tuberculosis H37Rv y un aislamiento clínico de M. chelonae. Metodología: Se obtuvo la concentración mínima inhibitoria (CMI) de los mismos y se realizaron curvas de letalidad para establecer actividad bactericida, empleando una técnica de macrodilución en caldo estandarizada para este tipo de compuestos volátiles. Resultados: Los terpenos con menor valor de CMI fueron timol y carvacrol, con concentraciones de 125-250 µg/mL, y actividad bactericida contra los dos microorganismos. Geraniol, mirceno, p-cimeno, alfa-pineno, presentaron valores de CMI entre 250 y 500 µg/mL. Conclusiones: Algunos terpenos han presentado actividad importante contra microorganismos del género Mycobacterium, sin embargo los valores de CMI obtenidos no explican el efecto antimicrobiano presentado por el aceite completo, se requiere evaluar las interacciones de sinergismo y/o antagonismo entre los terpenos para determinar los componentes responsables de la acción farmacológica.

Introduction: Tuberculosis (TB) caused by Mycobacterium tuberculosis is the major source of global mortality from a single pathogen. Moreover, a large number of nontuberculous mycobacteria, especially M. avium, M. intracellulare and M. chelonae, cause opportunistic infection in AIDS patients. Terpenes, possess a wide spectrum of biological activity and are used in the treatment of various diseases, reason that makes them a source of promising molecules. Objective: To determine the antimycobacterial activity of 16 terpenes against M. tuberculosis H37Rv and a clinical isolate of M. chelonae. Material and methods: Minimum Inhibitory Concentration (MIC) values of terpenes were obtained by macrodilution colorimetric method standardized for this kind of volatile compounds, time kill curves were determined to establish bactericidal activity using CLSIM26-A method. Results: Terpenes with the lower MIC values were thymol and carvacrol at concentrations of 125-250 µg/mL, showing bactericidal activity against both microorganisms. Geraniol, myrcene, p-cymene, and alpha - pinene, showed MIC values ranging between 250-500 µg/mL. Conclusion: Some terpenes have presented significant activity against microorganisms of the Mycobacterium genus, but the MIC values obtained do not explain the antimicrobial effect showed by the complete oil, is necessary to assess the interactions of synergism and / or antagonism between the terpenes to determine the components responsible for drug action.

Anti-tubercular activity of eleven aromatic and medicinal plants occurring in Colombia.

INTRODUCTION: Human tuberculosis is a contagious-infectious disease mainly caused by Mycobacterium tuberculosis. Although regimens exist for treating tuberculosis, they are far from ideal. Development of effective strategies for treatment of human tuberculosis has posed a challenge, considering the increase in infections associated with the human immunodeficiency virus and immunocompromised patients. Essential oils--volatile, aromatic oil extracts from plants--have been used in traditional treatment of many diseases; however careful investigation of these oils has not been undertaken with respect to treatments of tuberculosis. OBJECTIVE: The in vitro antitubercular activity of essential oils from 11 medicinal plants grown in Colombia were assessed for efficacy as new medications (phytomedicines) for treatment of M. tuberculosis H37Rv. MATERIAL AND METHODS: Essential oil extraction and analysis were performed as described Stashenko et al. (2004). Minimal inhibitory concentrations were determined by a colorimetric macrodilution method, following the protocol described by Abate et al. (1998). Isoniazide and rifampin were used as control treatments. Bactericidal and bacteriostatic activity was measured using the method developed by the Clinical and Laboratory Standards Institute consigned in the M26-A protocol. RESULTS: Essential oils from Achyrocline alata and Swinglea glutinosa were the most active with minimal inhibitory concentrations of 62.5 +/- 0.1 and 100 +/- 36 microg ml(-1), respectively. Carvacrol, thymol, p-cymene, 1,8-cineole, limonene, and beta-pinene were the major components, most often identified in the 11 plant extracts of essential oils. Time-kill curve assays demonstrated the bacteriostatic activity of these essential oils. CONCLUSIONS: The essential oils from A. alata and S. glutinosa plants, and the components identified therein, are candidates as potential phytotherapeutic agents for human tuberculosis control.

Actividad antituberculosa de plantas colombianas / Anti-tubercular activity of eleven aromatic and medicinal plants occurring in Colombia

Introduction. Human tuberculosis is a contagious-infectious disease mainly caused by Mycobacterium tuberculosis. Although regimens exist for treating tuberculosis, they are far from ideal. Development of effective strategies for treatment of human tuberculosis has posed a challenge, considering the increase in infections associated with the human immunodeficiency virus and immunocompromised patients. Essential oils -volatile, aromatic oil extracts from plants-have been used in traditional treatment of many diseases; however careful investigation of these oils has not been undertaken with respect to treatments of tuberculosis.Objective. The in vitro antitubercular activity of essential oils from 11 medicinal plants grown in Colombia were assessed for efficacy as new medications (phytomedicines) for treatment of M. tuberculosis H37Rv.Material and methods. Essential oil extraction and analysis were performed as described Stashenko et al. (2004). Minimal inhibitory concentrations were determined by a colorimetric macrodilution method, following the protocol described by Abate et al. (1998). Isoniazide and rifampin were used as control treatments. Bactericidal and bacteriostatic activity was measured using the method developed by the Clinical and Laboratory Standards Institute consigned in the M26-A protocol. Results. Essential oils from Achyrocline alata and Swinglea glutinosa were the most active with minimal inhibitory concentrations of 62.5 À0.1 and 100 À36 Ìg ml-1, respectively. Carvacrol, thymol, p-cymene, 1,8-cineole, limonene, and A-pinene were the major components, most often identified in the 11 plant extracts of essential oils. Time-kill curve assays demonstrated the bacteriostatic activity of these essential oils. Conclusions. The essential oils from A. alata and S. glutinosa plants, and the components identified therein, are candidates as potential phytotherapeutic agents for human tuberculosis control.

Introducción. La tuberculosis es una enfermedad infecto contagiosa causada por Mycobacterium tuberculosis. Aunque existen protocolos para su tratamiento, no son ideales. Actualmente, el desarrollo de estrategias terapéuticas efectivas ha tomado nuevos rumbos, considerando el incremento de pacientes positivos para el virus de la inmunodeficiencia humana. Los medicamentos basados en plantas medicinales se usan ampliamente en la medicina tradicional para el tratamiento de diversas afecciones. Los aceites esenciales obtenidos de plantas medicinales presentan amplia actividad antimicrobiana, sin embargo, existen pocos estudios que reporten la actividad antituberculosa de los mismos. Objetivo. Evaluar la actividad antituberculosa in vitro de 11 aceites esenciales provenientes de plantas medicinales que crecen en Colombia, los cuales podrían ser candidatos para el desarrollo de futuros fitofármacos. Materiales y métodos. La extracción y el análisis de los aceites esenciales se realizó bajo la metodología desarrollada por Stashenko et al.. La obtención de la concentración inhibitoria mínima se llevó a cabo por un método colorímetrico de macrodilución en caldo descrito por Abate y et al.; la isoniacida y la rifampicina se usaron como medicamentos control. La actividad bactericida y bacteriostética se determinaron mediante el protocolo M26-A del Clinical and Laboratory Standards Institute. Resultados. Los aceites esenciales provenientes de las plantas Achyrocline alata y Swinglea glutinosa fueron los más activos con concentraciones inhibitorias mínimas de 62.5 À0.1 y 100À36 Ìg ml-1, respectivamente. Carvacrol, timol, p-cymene, 1,8-cineole, limoneno, y Â-pineno fueron los componentes mayoritarios identificados en los 11 aceites. Los ensayos de curva de letalidad evidenciaron que ambos aceites son bacteriostáticos. Conclusiones. Los aceites esenciales obtenidos de las plantas A. alata y S. glutinosa, así como sus componentes, son candidatos potenciales como fitoterapéuticos para el control de la tuberculosis.

Distribución de las redias y cercarias de Fasciola hepática en una población silvestre de Lymnaea cubensis del occidente de Venezuela / Distribution of rediae and cercariae of fasciola hépatica in a silvester population of Lymnaea cubensis in Westwrn Venezuela

El estudio de una población de L. cubensis infectadas en condiciones naturales por las formas larvarias de Fasciola hépatica, nos permitió evidenciar la existencia de una relación inversa entre el tamaño del molusco L. cubensis y la sobre dispersión de las redias y cercarias de F. hépatica que la parasitan. Además, la abundancia de dichas formas larvarias, así como la prevalencia y la intensidad promedio se incrementan a medida que los moluscos son más grandes

Fasciolasis hepática en bovinos del estado Trujillo, Venezuela / Fasciolasis hepatica in cattle of the state of Trujillo, Venezuela

El análisis de la información recabada por funcionarios del Ministerio de Sanidad y Asistencia Social sobre decomisos de hígados de bovinos por distomatósicos en el estado Trujillo, nos permitió establecer los siguientes valores promedios: la prevalencia de distomatosis hepática para el matadero de Boconó (1971-1984) fue de 12,74%, con una pérdida de 125,21 Kg de hígado por cada 1.000 obtenidos y le correspondió a los meses de enero, marzo, julio, noviembre y diciembre, índices de decomisos superiores al promedio general; mientras que para el matadero de Jiménez (1975-1984), la prevalencia fue de 1,38% con una pérdida de 11,70 Kg de hígado por cada 1.000 obtenidos y con índices estacionales de decomisos más elevados en los meses de enero, abril e mayo. En lo referente a la prevalencia de esta parasitosis en animales vivos, se determinó que en los bovinos criados en zonas bajas (<1.000 m.s.n.m.) es de 36 + ou - 7%; mientras que en las altas (>1.000 m.s.n.m.) es de 49 + ou - 5%. Se demostró que F. hepatica se encuentra altamente sobredispersada en el seno de la población de hospedadores (K mensual = 0,03 y K = 0,02). Se suministra la lista de localidades en las cuales F. hepatica ha sido detectada