Electrochemical Exfoliation of Graphite in Aqueous Sodium Halide Electrolytes toward Low Oxygen Content Graphene for Energy and Environmental Applications.

Graphene and graphene-based materials have shown great promise in many technological applications, but their large-scale production and processing by simple and cost-effective means still constitute significant issues in the path of their widespread implementation. Here, we investigate a straightforward method for the preparation of a ready-to-use and low oxygen content graphene material that is based on electrochemical (anodic) delamination of graphite in aqueous medium with sodium halides as the electrolyte. Contrary to previous conflicting reports on the ability of halide anions to act as efficient exfoliating electrolytes in electrochemical graphene exfoliation, we show that proper choice of both graphite electrode (e.g., graphite foil) and sodium halide concentration readily leads to the generation of large quantities of single-/few-layer graphene nanosheets possessing a degree of oxidation (O/C ratio down to ∼0.06) lower than that typical of anodically exfoliated graphenes obtained with commonly used electrolytes. The halide anions are thought to play a role in mitigating the oxidation of the graphene lattice during exfoliation, which is also discussed and rationalized. The as-exfoliated graphene materials exhibited a three-dimensional morphology that was suitable for their practical use without the need to resort to any kind of postproduction processing. When tested as dye adsorbents, they outperformed many previously reported graphene-based materials (e.g., they adsorbed ∼920 mg g-1 for methyl orange) and were useful sorbents for oils and nonpolar organic solvents. Supercapacitor cells assembled directly from the as-exfoliated products delivered energy and power density values (up to 15.3 Wh kg-1 and 3220 W kg-1, respectively) competitive with those of many other graphene-based devices but with the additional advantage of extreme simplicity of preparation.

Investigating the Dispersion Behavior in Solvents, Biocompatibility, and Use as Support for Highly Efficient Metal Catalysts of Exfoliated Graphitic Carbon Nitride.

The liquid-phase exfoliation of graphitic carbon nitride (g-C3N4) to afford colloidal dispersions of two-dimensional flakes constitutes an attractive route to facilitate the processing and implementation of this novel material toward different technological applications, but quantitative knowledge about its dispersibility in solvents is lacking. Here, we investigate the dispersion behavior of exfoliated g-C3N4 in a wide range of solvents and evaluate the obtained results on the basis of solvent surface energy and Hildebrand/Hansen solubility parameters. Estimates of the three Hansen parameters for exfoliated g-C3N4 from the experimentally derived data yielded δD ≈ 17.8 MPa(1/2), δP ≈ 10.8 MPa(1/2), and δH ≈ 15.4 MPa(1/2). The relatively high δH value suggested that, contrary to the case of other two-dimensional materials (e.g., graphene or transition metal dichalcogenides), hydrogen-bonding plays a substantial role in the efficient interaction, and thus dispersibility, of exfoliated g-C3N4 with solvents. Such an outcome was attributed to a high density of primary and/or secondary amines in the material, the presence of which was associated with incomplete condensation of the structure. Furthermore, cell proliferation tests carried out on thin films of exfoliated g-C3N4 using murine fibroblasts suggested that this material is highly biocompatible and noncytotoxic. Finally, the exfoliated g-C3N4 flakes were used as supports in the synthesis of Pd nanoparticles, and the resulting hybrids exhibited an exceptional catalytic activity in the reduction of nitroarenes.

Hyperglycemia reduces functional expression of astrocytic Kir4.1 channels and glial glutamate uptake.

Diabetics are at risk for a number of serious health complications including an increased incidence of epilepsy and poorer recovery after ischemic stroke. Astrocytes play a critical role in protecting neurons by maintaining extracellular homeostasis and preventing neurotoxicity through glutamate uptake and potassium buffering. These functions are aided by the presence of potassium channels, such as Kir4.1 inwardly rectifying potassium channels, in the membranes of astrocytic glial cells. The purpose of the present study was to determine if hyperglycemia alters Kir4.1 potassium channel expression and homeostatic functions of astrocytes. We used q-PCR, Western blot, patch-clamp electrophysiology studying voltage and potassium step responses and a colorimetric glutamate clearance assay to assess Kir4.1 channel levels and homeostatic functions of rat astrocytes grown in normal and high glucose conditions. We found that astrocytes grown in high glucose (25 mM) had an approximately 50% reduction in Kir4.1 mRNA and protein expression as compared with those grown in normal glucose (5mM). These reductions occurred within 4-7 days of exposure to hyperglycemia, whereas reversal occurred between 7 and 14 days after return to normal glucose. The decrease in functional Kir channels in the astrocytic membrane was confirmed using barium to block Kir channels. In the presence of 100-µM barium, the currents recorded from astrocytes in response to voltage steps were reduced by 45%. Furthermore, inward currents induced by stepping extracellular [K(+)]o from 3 to 10mM (reflecting potassium uptake) were 50% reduced in astrocytes grown in high glucose. In addition, glutamate clearance by astrocytes grown in high glucose was significantly impaired. Taken together, our results suggest that down-regulation of astrocytic Kir4.1 channels by elevated glucose may contribute to the underlying pathophysiology of diabetes-induced CNS disorders and contribute to the poor prognosis after stroke.

Solución del caso 47. Hiperoxaluria primaria / Solution to case 47. Primary hyperoxaluria

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Critical assessment of the current guidelines for the management and treatment of morbidly obese patients.

An interdisciplinary panel of specialists met in Mallorca in the first European Symposium on Morbid Obesity entitled; "Morbid Obesity, an Interdisciplinary Approach". During the two and half days of the meeting, the participants discussed several aspects related to pathogenesis, evaluation, and treatment of morbid obesity. The expert panel included basic research scientists, dietitians and nutritionists, exercise physiologists, endocrinologists, psychiatrists, cardiologists, pneumonologists, anesthesiologists, and bariatric surgeons with expertise in the different weight loss surgeries. The symposium was sponsored by the Balearic Islands Health Department; however, this statement is an independent report of the panel and is not a policy statement of any of the sponsors or endorsers of the Symposium. The prevalence of morbid obesity, the most severe state of the disease, has become epidemic. The current recommendations for the therapy of the morbidly obese comes as a result of a National Institutes of Health (NIH) Consensus Conference held in 1991 and subsequently reviewed in 2004 by the American Society for Bariatric Surgery. This document reviews the work-up evaluation of the morbidly obese patient, the current status of the indications for bariatric surgery and which type of procedure should be recommended; it also brings up for discussion some important real-life clinical practice issues, which should be taken into consideration when evaluating and treating morbidly obese patients. Finally, it also goes through current scientific evidence supporting the potential effectiveness of medical therapy as treatment of patients with morbid obesity.

Utilidad de la profilaxis antibiótica en la reducción de la infección de herida en la reparación de la hernia inguinal o crural mediante malla de polipropileno / Utility of antibiotic prophylaxis in reducing wound infection in inguinal or femoral hernia repair using polypropylene mesh

Objetivo. Valorar, mediante un estudio prospectivo aleatorizado, la influencia de la profilaxis antibiótica sobre la incidencia de infección de herida quirúrgica, en la reparación de la hernia inguinal o crural mediante la utilización de prótesis sintéticas de polipropileno. Pacientes y método. Desde junio de 1994 a junio de 1997, fueron intervenidos de forma programada 554 pacientes con hernia inguinal o crural. Treinta pacientes fueron excluidos del estudio por diferentes razones: cirugía urgente (11), tra tamiento con citostáticos o corticoides (5), portadores de VIH/sida (2), portadores de neoplasias concomitantes (1), incumplimiento de la aleatoriedad del protocolo de inclusión (2), falta de seguimiento postoperatorio (2) y colocación de drenaje (7). La selección de pacientes fue aleatoria y doble ciego en dos grupos: cefazolina y placebo. Se realizó una estratificación de los pacientes según su riesgo biológico individual, medido por la clasificación de ASA. El seguimiento de los pacientes fue de 12 meses. La determinación de la homogeneidad de la muestra se realizó mediante tablas 2 * 2. El cálculo del riesgo relativo y odds ratio para un intervalo de confianza del 95 por ciento fue: RR = 1,13 (0,53-2,44). Las pruebas utilizadas fueron la *2 y la t de Student. Resultados. La edad media de los pacientes fue de 54,2 años (rango 17-87). La distribución por sexos fue de 471 varones (89,9 por ciento) y 53 mujeres (10,1 por ciento). El grupo con profilaxis se compuso de 233 pacientes con una tasa de infección de herida del 1,7 por ciento (4 casos). En el grupo placebo se incluyeron 281 pacientes con una tasa de infección de herida del 2,1 por ciento (6 casos) (*2 = 0,737; diferencia no estadísticamente significativa). La estratificación según la clasificación ASA fue la siguiente: ASA-I, 224 (42,7 por ciento); ASA-II, 219 (41,8 por ciento); ASA-III, 78 (14,9 por ciento). La morbilidad general de la serie fue del 7,7 por ciento, con 40 complicaciones (hematomas, 2,7 por ciento; seromas: 2,1 por ciento; infección de herida, 1,9 por ciento [10 casos]; neuropatía inguinal, 0,2 por ciento). De los 10 pacientes con infección de herida, 4 desarrollaron una sepsis local crónica que obligó a la retirada de la malla. Otras variables estudiadas y relacionadas con la infección de herida fueron la edad, duración de la intervención y el ASA, no encontrando diferencias significativas. Conclusiones. La utilización de profilaxis antibiótica no demostró una disminución significativa de la tasa de infección de la herida quirúrgica. Los pacientes con un mayor riesgo individual (ASA-III) parecen tener también un mayor riesgo de infección de herida, aunque en nuestro estudio la diferencia no fue significativa, probablemente por el reducido número de pacientes. La profilaxis antibiótica podría evitarse en un gran número de intervenciones al ser la hernioplastia inguinal uno de los procedimientos más frecuentes, lo que permitiría una reducción del gasto farmaceútico (AU)

Optometric manpower in the Commonwealth of Puerto Rico: estimates and projections, 1982-2025.

BACKGROUND: The 1982 study investigated the potential impact of the IAUPR School of Optometry on the adequacy of supply of optometrists in Puerto Rico for the years of 1980-2000. This article is designed to: (1) update the 1982 study; (2) appraise the accuracy of the 1982 projections; (3) re-evaluate the status of optometric manpower in Puerto Rico through the year 2025; and (4) provide the School of Optometry with information necessary to make informed judgments about future enrollments. METHODS: Estimates of supply are based on data from the Colegio de Optometras de Puerto Rico, the Sección de Oftalmología de la Asociación Médica de Puerto Rico, and the enrollment and graduation registries from the School of Optometry. Requirements are based on estimates of annual effective demand, provider-to-population ratios, per capita demand, and optometric productivity. RESULTS: Optometrists comprised 52.2% of Puerto Rico's actively practicing vision care manpower in 1995, with a mean optometrist-to-population ratio of 8.2 per 100,000. The number ranged from 28 in Mayagüez to 107 in San Juan. Under different assumptions regarding supply, productivity, and demand, surpluses and deficits are estimated and projected for the years 1995 to 2025. CONCLUSIONS: Depending on the assumptions used, an undersupply or an oversupply of optometrists may be found in Puerto Rico, currently and in the future. Projections of supply and demand predict a considerable range--from a surplus of 961 optometrists to a deficit of 2,085 optometrists in the year 2025.

Estimates of the prevalence of childhood maladjustment in a community survey in Puerto Rico. The use of combined measures.

A two-stage epidemiologic survey was carried out on a probability sample of the population aged 4 through 16 years in Puerto Rico. The survey used the Child Behavior Checklist as a screening instrument, and prevalence rates were estimated on the basis of clinical diagnoses and other measures provided by child psychiatrists during the second stage. Maladjustment was operationally defined through the use of combined measures, including DSM-III diagnosis and a scale of functional impairment. Data were provided on the demographic correlates of maladjustment and on the comorbidity of DSM-III diagnostic domains. The prevalence rates obtained vis-à-vis the availability of mental health services on the island reflected a major public health problem.