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The study of the optical properties of graphene oxide (GO) is crucial in designing functionalized GO materials with specific optical properties for various applications such as (bio) sensors, optoelectronics, and energy storage. The present work aims to investigate the electronic transitions, optical bandgap, and absorption coefficient of GO under different conditions. Specifically, the study examines the effects of drying times ranging from 0 to 120 h while maintaining a fixed temperature of 80°C and low temperatures ranging from 40â to 100â, with a constant drying time of 24 h. Our findings indicate that exposing the GO sample to a drying time of up to 120 h at 80°C can lead to a reduction in the optical bandgap, decreasing it from 4.09 to 2.76 eV. The π-π* transition was found to be the most affected, shifting from approximately 230 nm at 0 h to 244 nm after 120 h of drying time. Absorption coefficients of 3140-5507 ml mg-1 m-1 were measured, which are similar to those reported for exfoliated graphene dispersions but up to two times higher, confirming the improved optical properties of GO. Our findings can provide insights into determining the optimal temperature and duration required for transforming GO into its reduced form for a specific application through extrapolation. The study is complemented by analyzing the elemental composition, surface morphology change, and electrical properties.
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Graphene oxide (GO) and its reduced form, reduced graphene oxide (rGO), are among the most predominant graphene derivatives because their unique properties make them efficient adsorbent nanomaterials for water treatment. Although extra-functionalized GO and rGO are customarily employed for the removal of pollutants from aqueous solutions, the adsorption of heavy metals on non-extra-functionalized oxidized graphenes has not been thoroughly studied. Herein, the adsorption of mercury(II) (Hg(II)) on eco-friendly-prepared oxidized graphenes is reported. The work covers the preparation of GO and rGO as well as their characterization. In a further stage, the description of the adsorption mechanism is developed in terms of the kinetics, the associated isotherms, and the thermodynamics of the process. The interaction between Hg(II) and different positions of the oxidized graphene surface is explored by DFT calculations. The study outcomes particularly demonstrate that pristine rGO has better adsorbent properties compared to pristine GO and even other extra-functionalized ones.
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We present an analysis of the electronic and plasmonic behavior of periodic planar distributions of sufficiently wide graphene nanoribbons, for which a thorough ab initio investigation is practically unfeasible. Our approach is based on a semi-analytical model whose only free parameter is the charge carrier velocity, which we estimate by density-functional theory calculations on graphene. By this approach, we show that the plasmon resonance energies of the scrutinized systems fall in the lower THz band, relevant for optoelectronic and photonic applications. We further observe that these energies critically depend on the charge carrier concentration, ribbon width, electron relaxation rate, and in-plane transferred momentum angle, thus, suggesting a tunability of the associated light-matter modes.
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Mercury (Hg(II)) has been classified as a pollutant and its removal from aqueous sources is considered a priority for public health as well as ecosystem protection policies. Oxidized graphenes have attracted vast interest in water purification and wastewater treatment. In this report, a partially reduced graphene oxide is proposed as a pristine adsorbent material for Hg(II) removal. The proposed material exhibits a high saturation Hg(II) uptake capacity of 110.21 mg g-1, and can effectively reduce the Hg(II) concentration from 150 mg L-1 to concentrations smaller than 40 mg L-1, with an efficiency of about 75% within 20 min. The adsorption of Hg(II) on reduced graphene oxide shows a mixed physisorption-chemisorption process. Density functional theory calculations confirm that Hg atom adsorbs preferentially on clean zones rather than locations containing oxygen functional groups. The present work, therefore, presents new findings for Hg(II) adsorbent materials based on partially reduced graphene oxide, providing a new perspective for removing Hg(II).
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Mercúrio , Poluentes Químicos da Água , Purificação da Água , Adsorção , Ecossistema , Grafite , Concentração de Íons de Hidrogênio , Cinética , Mercúrio/análise , Água , Poluentes Químicos da Água/análiseRESUMO
Reduced graphene oxide (rGO) is one of the most well-known graphene derivatives, which, due to its outstanding physical and chemical properties as well as its oxygen content, has been used for wastewater treatment technologies. Particularly, extra functionalized rGO is widely preferred for treating wastewater containing dyes or heavy metals. Nevertheless, the use of non-extra functionalized (pristine) rGO for the removal of cationic pollutants is not explored in detail or is ambiguous. Herein, pristine rGO-prepared by an eco-friendly protocol-is used for the removal of cationic pollutants from water, i.e., methylene blue (MB) and mercury-(II) (Hg-(II)). This work includes the eco-friendly synthesis process and related spectroscopical and morphological characterization. Most importantly, the investigated rGO shows an adsorption capacity of 121.95 mg g-1 for MB and 109.49 mg g-1 for Hg (II) at 298 K. A record adsorption time of 30 min was found for MB and 20 min for Hg (II) with an efficiency of about 89% and 73%, respectively. The capture of tested cationic pollutants on rGO exhibits a mixed physisorption-chemisorption process. The present work, therefore, presents new findings for cationic pollutant adsorbent materials based on oxidized graphenes, providing a new perspective for removing MB molecules and Hg(II) ions.
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BACKGROUND: Chronic kidney disease (CKD) is one of the pathologies with the greatest impact on the public health system. Over the last few decades, the relevance of CKD in Mexico has increased, with associated overwhelming costs for care of renal disease. There are no reliable CKD statistics in Mexico. METHODOLOGY: In June 2018, the government of Aguascalientes called on all Health Institutions to create a state registry of treated end-stage renal disease (ESRD). In the same system, a renal biopsy result registry included all the native kidney biopsies obtained in the state of Aguascalientes since 2012. We herein describe the prevalence, incidence and characteristics of the patients included in the CKD and renal biopsy registry in the state of Aguascalientes. RESULTS: As of April 2020, the state has documented 2827 patients on renal replacement therapy (RRT), 1877 on dialysis and 950 that have been transplanted. The prevalence of patients on dialysis is 1326 per million population (p.m.p.), and if transplanted individuals are included, it is 1997 p.m.p. The incidence of treated ESRD in 2019 was 336 p.m.p. (n = 474) in individuals with an average age of 45.6 years (standard deviation ±18), and in a higher proportion of men (61%). There is a bimodal distribution of the age at which RRT was initiated. The first and the most significant peaks are between the ages of 20 and 40 years and are usually the result of CKD of unknown cause (73%). The second peak is between 50 and 70 years of age, and CKD is usually the result of diabetes mellitus and systemic arterial hypertension (59.6%). Since January 2012, 423 biopsies have been recorded. The patient's ages were between 20 and 30 years (n = 112), and the most frequent diagnosis was focal segmental glomerulosclerosis (FSGS) (54%). CONCLUSIONS: The prevalence of treated ESRD in the state of Aguascalientes is high. The disease mostly afflicts young people between 20 and 40 years of age, and there is a clear male predominance. In this age group, the main clinical diagnosis is CKD of unknown origin, and the most frequent biopsy diagnosis was FSGS.
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Graphene oxide (GO) exhibits different properties from those found in free-standing graphene, which mainly depend on the type of defects induced by the preparation method and post-processing. Although defects in graphene oxide are widely studied, we report the effect of drying time in GO and how this modifies the presence or absence of edge-, basal-, and sp3-type defects. The effect of drying time is evaluated by Raman spectroscopy, UV-visible spectroscopy, and transmission electron microscopy (TEM). The traditional D, G, and 2D peaks are observed together with other less intense peaks called the D', D*, D**, D+G, and G+D. Remarkably, the D* peak is activated/deactivated as a direct consequence of drying time. Furthermore, the broad region of the 2D peak is discussed as a function of its deconvoluted 2D1A, 2D2A, and D+G bands. The main peak in UV-visible absorption spectra undergoes a redshift as drying time increases. Finally, TEM measurements demonstrate the stacking of exfoliated GO sheets as the intercalated (water) molecules are removed.
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Recently, green-prepared oxidized graphenes have attracted huge interest in water purification and wastewater treatment. Herein, reduced graphene oxide (rGO) was prepared by a scalable and eco-friendly method, and its potential use for the removal of methylene blue (MB) from water systems, was explored. The present work includes the green protocol to produce rGO and respective spectroscopical and morphological characterizations, as well as several kinetics, isotherms, and thermodynamic analyses to successfully demonstrate the adsorption of MB. The pseudo-second-order model was appropriated to describe the adsorption kinetics of MB onto rGO, suggesting an equilibrium time of 30 min. Otherwise, the Langmuir model was more suitable to describe the adsorption isotherms, indicating a maximum adsorption capacity of 121.95 mg g-1 at 298 K. In addition, kinetics and thermodynamic analyses demonstrated that the adsorption of MB onto rGO can be treated as a mixed physisorption-chemisorption process described by H-bonding, electrostatic, and π - π interactions. These results show the potential of green-prepared rGO to remove cationic dyes from wastewater systems.
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The oxidative exfoliation of graphite is a promising approach to the large-scale production of graphene. Conventional oxidation of graphite essentially facilitates the exfoliation process; however, the oxidation procedure releases toxic gases and requires extensive, time-consuming steps of washing and reduction to convert exfoliated graphene oxide (GO) into reduced graphene oxide (rGO). Although toxic gases can be controlled by modifying chemical reactions, filtration, dialysis, and extensive sonication are unfavorable for large-scale production. Here, we report a complete, scalable, and green synthesis of GO, without NaNO3, followed by reduction with citric acid (CA). This approach eliminates the generation of toxic gases, simplifies the washing steps, and reduces the time required to prepare rGO. To validate the proposed method, we present spectroscopical and morphological studies, using energy-dispersive X-ray spectroscopy (EDS), UV-visible spectroscopy, infrared spectroscopy, Raman spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Thermal gravimetric analysis (TGA) is used to analyze the thermal properties of GO and rGO. This eco-friendly method proposes a complete guideline protocol toward large-scale production of oxidized graphene, with potential applications in supercapacitors, fuel cells, composites, batteries, and biosensors.
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INTRODUCTION: The lymphocytic choriomeningitis virus is an Old World arenavirus that infects Mus musculus, and can cause congenital hydrocephalus, chorioretinitis and multisystemic failure in transplant human recipients. Although the disease has not been clinically diagnosed in Colombia yet, there have been reports of infection with the Pichindé virus in rodents from Cauca and Valle del Cauca departments, and with the Guanarito virus in rodents from Córdoba department. OBJECTIVE: To identify the lymphocytic choriomeningitis virus from Mus musculus captured in the municipality of Sincelejo. MATERIALS AND METHODS: We evaluated 80 samples of plasma by ELISA using antigen from lymphocytic choriomeningitis virus. Additionally, a nested RT-PCR was performed to seropositive and seronegative samples for the S-segment. RESULTS: We found a 10% seroprevalence (8/80) and the viral genome was detected in 16 brain samples; the alignment (BLAST) and the phylogenetic analysis (MrBayes, version 3.2.2) confirmed the presence of the lymphocytic choriomeningitis virus. CONCLUSION: The results indicated that human infection with the lymphocytic choriomeningitis virus in humans could occur in the urban area of Sincelejo, although no cases have been reported so far.
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Anticorpos Antivirais/sangue , Infecções por Arenaviridae/virologia , Ensaio de Imunoadsorção Enzimática/métodos , Vírus da Coriomeningite Linfocítica/imunologia , Roedores/virologia , Animais , Anticorpos Antivirais/análise , Encéfalo , Colômbia/epidemiologia , Humanos , Vírus da Coriomeningite Linfocítica/química , Camundongos , Filogenia , Estudos SoroepidemiológicosRESUMO
Resumen Introducción. El virus de la coriomeningitis linfocítica es un arenavirus del Viejo Mundo que se hospeda en el ratón casero (Mus musculus), y puede causar infecciones congénitas, hidrocefalia, coriorretinitis y falla orgánica múltiple en pacientes receptores de trasplantes. En Colombia aún no se ha reportado la enfermedad mediante diagnóstico clínico, pero en estudios serológicos se ha detectado la infección por el virus Pichindé en roedores en los departamentos del Cauca y Valle del Cauca, y por el virus Guanarito, en roedores en Córdoba. Objetivo. Detectar el virus de la coriomeningitis linfocítica en M. musculus en el municipio de Sincelejo. Materiales y métodos. Se evaluaron 80 muestras de plasma mediante la prueba ELISA usando antígeno del virus de la coriomeningitis linfocítica. Además, se empleó la reacción en cadena de la polimerasa con transcriptasa inversa (RT-PCR) anidada en muestras de animales seropositivos y seronegativos para la detección del segmento S. Resultados. Se encontró una seroprevalencia de 10% (8/80) y se detectó el genoma viral en 16 muestras de cerebro; el alineamiento (en la Basic Local Alignment Search Tool, BLAST) y el análisis filogenético (mediante el programa MrBayes, versión 3.2.2) confirmaron que correspondía al virus de la coriomeningitis linfocítica. Conclusión. Los resultados indicaron que la infección por el virus de la coriomeningitis linfocítica en humanos podría ocurrir en el área urbana de Sincelejo, aunque hasta la fecha no se hayan reportado casos.
Abstract Introduction: The lymphocytic choriomeningitis virus is an Old World arenavirus that infects Mus musculus, and can cause congenital hydrocephalus, chorioretinitis and multisystemic failure in transplant human recipients. Although the disease has not been clinically diagnosed in Colombia yet, there have been reports of infection with the Pichindé virus in rodents from Cauca and Valle del Cauca departments, and with the Guanarito virus in rodents from Córdoba department. Objective: To identify the lymphocytic choriomeningitis virus from Mus musculus captured in the municipality of Sincelejo. Materials and methods: We evaluated 80 samples of plasma by ELISA using antigen from lymphocytic choriomeningitis virus. Additionally, a nested RT-PCR was performed to seropositive and seronegative samples for the S-segment. Results: We found a 10% seroprevalence (8/80) and the viral genome was detected in 16 brain samples; the alignment (BLAST) and the phylogenetic analysis (MrBayes, version 3.2.2) confirmed the presence of the lymphocytic choriomeningitis virus. Conclusion: The results indicated that human infection with the lymphocytic choriomeningitis virus in humans could occur in the urban area of Sincelejo, although no cases have been reported so far.
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Animais , Humanos , Camundongos , Roedores/virologia , Ensaio de Imunoadsorção Enzimática/métodos , Infecções por Arenaviridae/virologia , Vírus da Coriomeningite Linfocítica/imunologia , Anticorpos Antivirais/sangue , Filogenia , Encéfalo , Estudos Soroepidemiológicos , Colômbia/epidemiologia , Vírus da Coriomeningite Linfocítica/química , Anticorpos Antivirais/análiseRESUMO
OBJECTIVE: Proof-of-concept study of evaluation of metabolic effect of novel oral spray insulin (Oralin) formulation at breakfast time in subjects with type 2 diabetes on multiple daily injections. RESEARCH DESIGN AND METHODS: This was an open-label, crossover, randomized study in (n = 23) subjects with type 2 diabetes on multiple daily injections. Subjects received each treatment, in random order, 3 to 7 days apart-a daily dose of SC injection (0.1 u/kg) on one occasion and Oralin spray (100 u) at time 0 min on another occasion. Subjects were given a standard breakfast containing 360 cal (Sustacal liquid meal) 10 min after the dose. Blood samples were taken at regular intervals to measure glucose, insulin, and C-peptide. RESULTS: The 30- and 60-min postprandial glucose levels were significantly lowered with Oralin versus that with the injection treatment (146 +/- 5 mg/dL Oralin vs 184 +/- 7 mg/dL injection at 30 min and 192 +/- 6 mg/dL Oralin vs 236 +/- 9 mg/dL injection, p < 0.003 at 60 min). The rise in serum insulin levels was significantly higher (Cmax = 98 +/- 6 uU/mL for Oralin at 30 min vs 65 +/- 3 uU/ml injection, p < 0.001). The reduction in C-peptide was greater in Oralin during the first 60 min (1.38 +/- 0.21 ng/mL Oralin vs 1.75 +/- 0.38 ng/mL injection, p < 0.001). CONCLUSIONS: This proof-of-concept study results demonstrated that Oralin could be used as meal insulin in place of mealtime-insulin injections in subjects with type 2 diabetes to regulate the postprandial glucose levels.
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Diabetes Mellitus Tipo 2/tratamento farmacológico , Hipoglicemiantes/administração & dosagem , Insulina/administração & dosagem , Administração Oral , Aerossóis , Glicemia/metabolismo , Peptídeo C/sangue , Estudos Cross-Over , Diabetes Mellitus Tipo 2/sangue , Relação Dose-Resposta a Droga , Esquema de Medicação , Feminino , Humanos , Hipoglicemiantes/uso terapêutico , Injeções Subcutâneas , Insulina/sangue , Insulina/uso terapêutico , Masculino , Pessoa de Meia-Idade , Período Pós-Prandial , Resultado do TratamentoRESUMO
The aim of this study was to determine the metabolic effect and the safety of a novel oral insulin spray (Oralin) formulation at breakfast-time in subjects with type 2 diabetes with suboptimal glucose control and maintained on a combination therapy of oral hypoglycemic agents (OHAs). This was an open-label, crossover, randomized study design in subjects (n = 21) with type 2 diabetes (glycated hemoglobin A1c >8.0%). Subjects received each of the following treatments, in random order: metformin + glyburide and placebo puffs at time 0 min; or metformin + glyburide and Oralin spray (100 U) at time 0 min. Fifteen minutes later, subjects were given a standard breakfast containing 360 calories [Sustacal (Mead Johnson, Evansville, IN) liquid meal]. Blood samples were taken at regular intervals to measure serum glucose, insulin, and C-peptide. Time-averaged postprandial glucose increments (PPGIs) between 0 and 240 min were calculated for each treatment. Group mean PPGIs to OHAs versus Oralin in combination with OHAs were compared to determine the mean efficacy of the active treatment. The Oralin spray lowered the 2-h postprandial glucose rise significantly in comparison with the OHAs alone. The serum insulin levels were significantly higher with faster onset of action in the Oralin spray treatment when compared with the OHAs treatment. The reductions in C-peptides were also significantly greater in the Oralin arm than in the OHAs treatment. This study results demonstrated that Oralin could be used as meal insulin as an add-on therapy in combination with failing OHAs treatment in subjects with type 2 diabetes to regulate postprandial glucose levels.
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Diabetes Mellitus Tipo 2/tratamento farmacológico , Glibureto/administração & dosagem , Hipoglicemiantes/administração & dosagem , Insulina/administração & dosagem , Metformina/administração & dosagem , Administração Oral , Adulto , Idoso , Glicemia/efeitos dos fármacos , Glicemia/metabolismo , Peptídeo C/sangue , Estudos Cross-Over , Diabetes Mellitus Tipo 2/sangue , Esquema de Medicação , Quimioterapia Combinada , Feminino , Humanos , Insulina/sangue , Insulina/metabolismo , Secreção de Insulina , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Estatísticas não ParamétricasRESUMO
Los problemas nasosinusales de tipo poliposis y sinusitis crónica que no responden a tratamiento clínico adecuado requieren de cirugía; desde 1993 los autores realizan una nueva técnica en el tratamiento de esta patología se trata de la cirugía funcional endoscópica naso-sinusal (CFENS), esta técnica se ha realizado en 94 pacientes en 13 patologías diferentes siendo las más frecuentes la poliposis naso-sinusal y la sinusitis crónica. Los resultados y complicaciones de esta técnica la hacen la elección para la gran mayoría de patología de los senos paranasales.
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SinusiteRESUMO
Se comparó la sensibilidad de la cuerda encapsulada con el examen seriado de heces, para demostrar parasitismo intestinal en treinta pacientes admitidos en el Servicio de Tropa del Hospital MIlitar Central. Los resultados demostraron una alta incidencia de parasitismo intestinal en nuestros pacientes, una baja sensibilidad de la cuerda encapsulada y la elevada morbilidad que produce esta infestación: anemia crónica, diarrea y desnutrición.
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Humanos , Masculino , Adolescente , Adulto , Diagnóstico , Fezes , Enteropatias Parasitárias , Sensibilidade e EspecificidadeRESUMO
Se presenta una paciente de 44 años de edad, proveniente de Iquitos con fiebre de tres meses de evolución y pérdida progresiva de peso; el examen clínico fue normal a excepción de hepatomegalia moderada. Frente a este síndrome febril crónico de origen desconocido, se programó una serie de procedimientos y exámenes auxiliares en forma gradual y sistemática; siguiendo un protocolo previamente establecido en nuestro servicio para estos casos. La biopsia laparoscópica del hígado mostró conglomerados linfomonocitarios múltiples y Mycobacterium tuberculosis. La evolución de la paciente luego del tratamiento específico fue satisfactoria, dándosele de alta (diecinueve días después de iniciarse la terapia) afebril, en buenas condiciones físicas para continuar su tratamiento en forma ambulatoria. Presentamos esta paciente con tuberculosis extrapulmonar hepática micronodular múltiple que cursa con fiebre de más de tres semanas de evolución para insistir que en nuestro medio es necesario considerar esta etiología, dada su prevalencia, como causa de síndrome febril crónico de origen desconocido en pacientes adultos con hepatomegalia.