Single walled carbon nanotubes covalently functionalized by a ruthenium complex for photocatalytic oxidations.

The covalent bonding of a ruthenium bipyridine complex derivative with the aromatic network of single walled carbon nanotubes (SWNT) through a stepwise protocol is presented, thus yielding the sample SWNT-Ru. To do that, an-amino decorated phenanthroline is bonded to the nanotube by means of the diazonium chemistry protocol, providing anchoring points for discrete organometallic units as depicted by the solid characterization techniques employed. The hybrid material, able to emit upon excitation, is active in the visible light-driven photocatalytic oxidation of organic sulfides to sulfoxides. SWNT-Ru presents a wide scope being able to convert more than 10 substrates with different characteristics, including added-value chemicals, with a stable performance over more than 6 cycles without metal leaching and enhanced activity compared to related homogeneous complexes. A versatile character is also demonstrated since this hybrid catalyst follows both possible photooxidation mechanisms.

Student training in administering inferior alveolar nerve block anesthesia with a simple manufactured simulation model.

OBJECTIVE: To compare the effectiveness of administering inferior alveolar nerve blocks (IANB) for the first time with or without a previous practical lesson using a simple manufactured simulator. METHODS: This was a study designed to compare students' first administration of IANB anesthesia during 2022, with or without a previous practical lesson. Students were randomized into two groups. The experimental group attended both theoretical lessons and a practical lesson with a simulator device, while the control group attended only theoretical lessons. The theoretical lesson included usual contents such as anatomy, physiology, technical maneuvers for administering anesthesia, tips, and complications, and the practical lesson consisted of the administration of anesthesia using a simple manufactured simulator. After students applied their first IANB, its efficacy, and their answers to a questionnaire on a 5-point Likert scale were recorded. Statistical analysis consisted of the Chi-square test (p < 0.05). RESULTS: The study recorded 60 anonymous surveys. The main difference observed was in instrument handing (p < 0.05), and there was a tendency in the ease of recognition of the anatomical marks used for the technique-pterygomandibular raphe and coronoid notch of the mandible (p = 0.08 and 0.11, respectively). No difference in success was observed (p > 0.05). Self-confidence and personal feelings did not differ statistically. All students agreed strongly or partially that training with the simulator model was helpful. CONCLUSION: Students who used simple manufactured simulators achieved better outcomes for instrument handling, and possibly for identification of anatomical landmarks, than those who received only theoretical lessons.

Análisis de datos intra y postquirúrgicos en exodoncias unitarias realizadas por alumnos de grado de la FOUBA / Analysis of intra and post-surgical data in single extractions performed by FOUBA undergraduate studens

La exodoncia es el procedimiento odontológico más antiguo del que se tiene registro, pero pocas publi-caciones abarcan con detalle esta temática. Conocer los pormenores de esta práctica puede servir para generar políticas educativas, sanitarias, como así también sistematizarla y bajar así sus riesgos y complicaciones. El objetivo del presente estudio fue describir y analizar variables quirúrgicas asocia-das a las extracciones unitarias de piezas dentarias. Los datos se analizaron mediante las pruebas Chi-cuadrado de Pearson, exacta de Fisher y Kruskal-Wallis, según lo que correspondía (p<0,05, signifi-cativo). Concurrieron más mujeres que hombres, con una mediana de edad de 37 años (intervalo, 18 a 86), siendo los terceros molares las piezas más ex-traídas. La pieza que requirió más odontosecciones fue el primer molar superior, mientras que la pieza que requirió más alveolectomías fue el tercer mo-lar inferior, siendo esta última la pieza con mayores complicaciones intra y post quirúrgicas, incluso una alteración nerviosa. La caries penetrante fue amplia-mente el motivo más frecuente de exodoncias (79%) superando los reportes en estudios similares, La du-ración promedio (DE) de las extracciones unitarias fue de 39 minutos (21), pero difirió significativamente entre piezas dentarias (p<0,05). Las complicaciones post quirúrgicas se asociaron significativamente a cirugías más prolongadas (p<0,05). La cantidad de anestubos utilizados también difirió significativa-mente entre piezas dentarias (p<0,05), siendo el sec-tor posterior inferior el que más cantidad necesitó. Los datos aportados en el estudio pueden ser utiliza-dos para mejorar recursos en los servicios de salud odontológicos (AU)

Dental extractions are the first procedures reported in dentistry, but few articles focus on its individual details. With proper information, educational and health policies could be systematically improved, and thus reduce risks and complications. The aim of the study was to describe and analyze surgical variables associated with single tooth extractions performed by students. The practice of 500 single extractions on 500 patients who attended the Oral and Maxillofacial service of the School of Dentistry of the University of Buenos Aires, between September 2021 and September 2022, performed by fourth-year students supervised by teachers, are described. Data were analyzed using Pearson's Chi-square, Fisher's exact or Kruskal-Wallis tests, as appropriate (p<0.05, significant). More women attended than men, with a median age of 37 years (range 18 to 86), with third molars being the most extracted pieces. Decay teeth was by far the most frequent reason for extractions (79%), exceeding reports in similar studies, that may be explained by a younger sample and the multiple extractions exclusion. The tooth that required the most sections was the upper first molar, while the tooth that required the most alveolectomies was the lower third molar, the latter being the tooth with the greatest intra- and post-surgical complications, including a reported nerve damage. The average duration (SD) of single extractions was 39 minutes (21), but it differed significantly between teeth (p<0.05), for example, upper central incisors presented an average of 21 (9), and upper first premolars 47 (25), characteristics not reported to date. As other studies reported, post-surgical complications were significantly associated with longer surgeries (p<0.05). The amount of anesthesia cartridges used also differed significantly between teeth (p<0.05), being the posterior mandible the one that needed the most amount. The data provided in the study can be systematically used to improve temporal and economic resources in dental health services (AU)

A Graphene Acid - TiO2 Nanohybrid as Multifunctional Heterogeneous Photocatalyst for the Synthesis of 1,3,4-Oxadiazoles.

The immobilization of TiO2 nanoparticles on graphene acid (GA), a conductive graphene derivative densely functionalized with COOH groups, is presented. The interaction between the carboxyl groups of the surface and the titanium precursor leads to a controlled TiO2 heterogenization on the nanosheet according to microscopic and spectroscopic characterizations. Electronic communication shared among graphene and semiconductor nanoparticles shifts the hybrid material optical features toward less energetic radiation but maintaining the conductivity. Therefore, GA-TiO2 is employed as heterogeneous photocatalyst for the synthesis of 2,5-disubstituted 1,3,4-oxadiazoles using ketoacids and hydrazides as substrates. The material presented enhanced photoactivity compared to bare TiO2, being able to yield a large structural variety of oxadiazoles in reaction times as fast as 1 h with full recyclability and stability. The carbocatalytic character of GA is the responsible for the substrates condensation and the GA-TiO2 light interaction ability is able to photocatalyze the cyclization to the final 1,3,4-oxadiazoles, demonstrating the optimal performance of this multifunctional photocatalytic material.

An Improved Immunization Record to Support Vaccination During the COVID-19 Pandemic at a University Hospital in Argentina.

WHO and UNICEF highlight vaccination as the most cost-effective method of prevention of infectious diseases. An effective public health strategy requires efficient tracking of vaccination to assess coverage, safety, and efficacy of these vaccines. Paper-based immunization records are still being used in most low and middle-income countries. Adequate Electronic Logistic Management Information Systems, Immunization Registries and Records are crucial for proper data collection and analysis, and for making better decisions at an individual and at a population level. In this paper we share our experience in the redesign of an interoperable immunization record to track vaccination, including the recently developed vaccines for the novel coronavirus SARS-CoV-2 (COVID-19).

Bleeding Complications in Relation to the International Normalized Ratio for Dental Extractions in Patients under Chronic Anticoagulant Therapy - An Evaluative Study.

Introduction: Recent simple dental extraction protocols suggest that therapeutic levels of the anticoagulant drug should be maintained because bleeding complications could be managed with local haemostasis manoeuvres. The aim of the present study was to evaluate the association between bleeding complications and the international normalized ratio (INR) values in patients after dental extractions completed with a plug of bismuth subgallate, without interrupting anticoagulant administration. Materials and Methods: Patients undergoing oral Vitamin K antagonist chronic anticoagulant therapy requiring simple dental extractions were included in the study. INRs were recorded on the day of the surgery, and dental extractions were performed applying bismuth subgallate as a haemostatic agent. Patients took their anticoagulation drug normally. Bleeding complications were recorded. Results: The study included 694 patients, of whom 11 (1.58%) presented mediate post-operative bleeding that was effectively controlled through local manoeuvres. No episode of thromboembolism or infectious endocarditis was observed. The incidence of bleeding complications was not related to the INR values (P > 0.05). Discussion: INR values were not related to bleeding complications when simple dental extractions were performed applying bismuth subgallate as a haemostatic agent.

Utilización del colgajo de bola adiposa de Bichat para el cierre inmediato de defectos quirúrgicos en el paladar. Reporte de dos casos / Use of the Bichat fat ball flap for immediate closure of surgical defects in the palate. Report of two cases

El objetivo fue describir la utilización del colgajo de bola adiposa de Bichat en el cierre de defectos palatinos inmediato a la resección quirúrgica. Casos clínicos: el caso clínico número 1 (hombre de 60 años) se presentó a la consulta con un aumento de volumen en mucosa del paladar blando, de forma ovoidal, no dolorosa a la palpación, coloración similar de la mucosa del paladar, de 3 cm de diámetro y de 4 meses de evolución que le incomoda para hablar y alimentarse. El caso clínico número 2 (hombre de 61 años) concurre a la consulta con una lesión en maxilar superior a nivel del paladar con diagnóstico patológico de adenoma pleomorfo. En ambos casos, se realizó la resección tumoral y la reconstrucción inmediata mediante el uso de bola adiposa de Bichat. Los defectos fueron cubiertos solamente por el tejido adiposo mencionado, generando una restitución ad integrum de la mucosa oral, evolucionaron favorablemente, sin complicaciones postoperatorias y recuperando la función masticatoria en pocas semanas. El colgajo de bola adiposa de Bichat debe ser considerado una alternativa para reparación de defectos postquirúrgicos gracias a su proximidad, disponibilidad, plasticidad y excelente vascularización, evitando así posibles secuelas relacionadas a la cicatrización secundaria.

The objective was to describe the use of the Bichat fat ball flap in the closure of palatal defects immediately after surgical resection. Clinical cases: clinical case number 1 (60-year-old man) presented to the consultation with an increase in volume of the soft palate mucosa, ovoid in shape, not painful on palpation, similar coloration of the palate mucosa, of 3 cm in diameter and 4 months of evolution that makes it uncomfortable to talk and feed. Clinical case number 2 (a 61-year-old man) attended the consultation with a lesion in the upper jaw at the level of the palate with a pathological diagnosis of pleomorphic adenoma. In both cases, tumor resection and immediate reconstruction were performed using a Bichat fat ball. The defects were covered only by the adipose tissue mentioned, generating a restitution ad integrum of the oral mucosa, they evolved favorably, without postoperative complications and recovering the masticatory function in a few weeks. The Bichat adipose ball flap should be considered an alternative for the repair of postsurgical defects thanks to its proximity, availability, plasticity and excellent vascularization, thus avoiding possible sequelae related to secondary healing.

Hybridization of Molecular and Graphene Materials for CO2 Photocatalytic Reduction with Selectivity Control.

In the quest for designing efficient and stable photocatalytic materials for CO2 reduction, hybridizing a selective noble-metal-free molecular catalyst and carbon-based light-absorbing materials has recently emerged as a fruitful approach. In this work, we report about Co quaterpyridine complexes covalently linked to graphene surfaces functionalized by carboxylic acid groups. The nanostructured materials were characterized by X-ray photoemission spectroscopy, X-ray absorption spectroscopy, IR and Raman spectroscopies, high-resolution transmission electron microscopy and proved to be highly active in the visible-light-driven CO2 catalytic conversion in acetonitrile solutions. Exceptional stabilities (over 200 h of irradiation) were obtained without compromising the selective conversion of CO2 to products (>97%). Most importantly, complete selectivity control could be obtained upon adjusting the experimental conditions: production of CO as the only product was achieved when using a weak acid (phenol or trifluoroethanol) as a co-substrate, while formate was exclusively obtained in solutions of mixed acetonitrile and triethanolamine.

Enhancing Visible-Light Photocatalysis via Endohedral Functionalization of Single-Walled Carbon Nanotubes with Organic Dyes.

The encapsulation of an organic dye, 10-phenylphenothiazine (PTH), in the inner cavity of single-walled carbon nanotubes (SWNTs) as a breaking heterogenization strategy is presented. The PTH@oSWNT material was microscopically and spectroscopically characterized, showing intense photoemission when illuminated with visible light at the nanoscale. Thus, PTH@oSWNT was employed as a heterogeneous photocatalyst in single electron transfer dehalogenation reactions under visible light irradiation. The material showed an enhanced photocatalytic activity, achieving turnover numbers as high as 3200, with complete recyclability and stability for more than eight cycles. Computational calculations confirm that electronic communication between both partners is established because, upon illumination, an electron of the excited PTH is transferred from the π system of the molecule to the delocalized π-cloud of the SWNT, thus justifying the enhanced photocatalytic activity.

Accidental Intravascular Local Anesthetic Injection of the Facial Artery.

Local anesthesia techniques are widely used in dentistry because of their numerous advantages, including safety. Several articles have been published on local and systemic complications stemming from the use of local anesthesia, one of which is accidental intravascular injection, usually reported during inferior alveolar nerve blocks. A 58-year-old man presented to the dental office for extraction of the lower left first molar. During delivery of a supplemental injection in the buccal vestibular mucosa to anesthetize the buccal nerve, an accidental intra-arterial injection to the facial artery occurred, causing sudden sharp pain and immediate pallor along the course of the facial artery. The pallor resolved in approximately 20 minutes. Buccal infiltration was repeated successfully, and the tooth was extracted uneventfully. This case appears to be the first report in the literature to describe the accidental intravascular injection of local anesthetic involving the facial artery and discuss its clinical implications.

Trigeminal nerve injuries. Four years' experience at a single Argentine referral center and a literature review.

The aim of this retrospective study was to describe the etiology and characteristics of trigeminal nerve injuries referred to a specialized center in Buenos Aires, Argentina. A retrospective analysis was performed of patients referred from February 2016 to January 2020. Age, sex, intervention performed, nerve affected, time elapsed from injury, diagnosis, location, and whether patient had signed informed consent were recorded. A descriptive analysis of the data was made, and 95% confidence intervals were calculated for prevalence. The study sample consisted of 30 subjects (31 nerve injuries), 19 female and 11 male, average age (±SD) 40 ± 17 years. The inferior alveolar nerve was the most frequently injured nerve (74%,) while the lingual nerve accounted for 26%. The most common etiologies were inferior molar extractions (47%), dental implants (20%), and local anesthesia (13%). Other etiologies were autologous mandibular bone grafts for dental implants, removal of cysts associated with the inferior third molar, and endodontic treatment. Dental Institutions at which treatment was provided were found to be significantly associated with patients being warned and asked to sign informed consent (p<0.05), while dentists working at private offices requested fewer consents. The most frequent symptom was paresthesia, and 5 patients suffered spontaneous or evoked pain. Only 2 patients intended to file legal claims. Dentists should be aware of the debilitating effects resulting from trigeminal injuries, the complexity of their resolution and the importance of carefully planning dental procedures to prevent them.

El objetivo de este estudio fue describir la etiología y características de las lesiones del nervio trigémino remitidas a un servicio de referencia especializado en Buenos Aires, Argentina. Se realizó un análisis retrospectivo de los pacientes remitidos desde febrero de 2016 a enero de 2020. Se registraron edad, género, intervención recibida, nervio afectado, tiempo transcurrido desde la lesión, diagnóstico, ubicación y firma del consentimiento informado previo a la intervención Se realizó un análisis descriptivo de los datos y se calcularon intervalos de confianza del 95%. La muestra del estudio consistió en 30 sujetos (31 lesiones nerviosas), 19 mujeres y 11 hombres, con una edad promedio (± DE) de 40 ± 17 años. Aproximadamente 3 de cada 4 lesiones correspondieron al nervio alveolar inferior, representando el resto al nervio lingual. Las etiologías más frecuentes fueron la extracción dentaria (47%), los implantes dentales (20%) y la aplicación anestesia local (13%). Otras etiologías fueron la regeneración ósea para la colocación de implantes mandibulares, la extirpación de quistes asociados al tercer molar inferior y el tratamiento endodóntico. Se encontró que el tipo de establecimiento donde se realizó el procedimiento odontológico que generó la lesión, se asoció significativamente con los pacientes a los que se les advirtió y se les pidió que firmen el consentimiento informado (p<0.05); los odontólogos que trabajan en consultorios privados obtienen una menor proporción de consentimientos que los de las instituciones. El síntoma más frecuente fue la parestesia y 5 pacientes sufrieron dolor espontáneo o evocado. Solo 2 pacientes tenían intención de iniciar acciones legales. Teniendo en cuenta que son lesiones potencialmente permanentes, y de resolución compleja, la comunidad odontológica debe realizar especiales esfuerzos para disminuir esta complicación.

Trigeminal nerve injuries. Four years' experience at a single Argentine referral center and a literature review / Lesiones del nervio trigémino. Cuatro años de experiencia de un servicio quirúrgico odontológico en Argentina y revisión bibliográfica

ABSTRACT The aim of this retrospective study was to describe the etiology and characteristics of trigeminal nerve injuries referred to a specialized center in Buenos Aires, Argentina. A retrospective analysis was performed of patients referred from February 2016 to January 2020. Age, sex, intervention performed, nerve affected, time elapsed from injury, diagnosis, location, and whether patient had signed informed consent were recorded. A descriptive analysis of the data was made, and 95% confidence intervals were calculated for prevalence. The study sample consisted of 30 subjects (31 nerve injuries), 19 female and 11 male, average age (±SD) 40 ± 17 years. The inferior alveolar nerve was the most frequently injured nerve (74%,) while the lingual nerve accounted for 26%. The most common etiologies were inferior molar extractions (47%), dental implants (20%), and local anesthesia (13%). Other etiologies were autologous mandibular bone grafts for dental implants, removal of cysts associated with the inferior third molar, and endodontic treatment. Dental Institutions at which treatment was provided were found to be significantly associated with patients being warned and asked to sign informed consent (p<0.05), while dentists working at private offices requested fewer consents. The most frequent symptom was paresthesia, and 5 patients suffered spontaneous or evoked pain. Only 2 patients intended to file legal claims. Dentists should be aware of the debilitating effects resulting from trigeminal injuries, the complexity of their resolution and the importance of carefully planning dental procedures to prevent them.

RESUMEN El objetivo de este estudio fue describir la etiología y características de las lesiones del nervio trigémino remitidas a un servicio de referencia especializado en Buenos Aires, Argentina. Se realizó un análisis retrospectivo de los pacientes remitidos desde febrero de 2016 a enero de 2020. Se registraron edad, género, intervención recibida, nervio afectado, tiempo transcurrido desde la lesión, diagnóstico, ubicación y firma del consentimiento informado previo a la intervención Se realizó un análisis descriptivo de los datos y se calcularon intervalos de confianza del 95%. La muestra del estudio consistió en 30 sujetos (31 lesiones nerviosas), 19 mujeres y 11 hombres, con una edad promedio (± DE) de 40 ± 17 años. Aproximadamente 3 de cada 4 lesiones correspondieron al nervio alveolar inferior, representando el resto al nervio lingual. Las etiologías más frecuentes fueron la extracción dentaria (47%), los implantes dentales (20%) y la aplicación anestesia local (13%). Otras etiologías fueron la regeneración ósea para la colocación de implantes mandibulares, la extirpación de quistes asociados al tercer molar inferior y el tratamiento endodóntico. Se encontró que el tipo de establecimiento donde se realizó el procedimiento odontológico que generó la lesión, se asoció significativamente con los pacientes a los que se les advirtió y se les pidió que firmen el consentimiento informado (p<0.05); los odontólogos que trabajan en consultorios privados obtienen una menor proporción de consentimientos que los de las instituciones. El síntoma más frecuente fue la parestesia y 5 pacientes sufrieron dolor espontáneo o evocado. Solo 2 pacientes tenían intención de iniciar acciones legales. Teniendo en cuenta que son lesiones potencialmente permanentes, y de resolución compleja, la comunidad odontológica debe realizar especiales esfuerzos para disminuir esta complicación.

Análisis retrospectivo de implantes para sobredentaduras en maxilar inferior, en el marco de la formación de recursos humanos / Retrospective analysis of dental implants placed in the lower jaw, within the post graduate dental training framework

Objetivo: Evaluar el porcentaje de implantes oseointegrados colocados en pacientes edéntulos para la confección de sobredentaduras inferiores, en el marco de la formación de recursos humanos. Materiales y métodos: Se analizaron las historias clínicas de los pacientes que recibieron dos implantes dentales inferiores para la confección de sobredentaduras en el servicio de residentes de la carrera de Especialización en Cirugía y Traumatología Bucomaxilofacial de la Facultad de Odontología de la Universidad de Buenos Aires, entre agosto de 2012 y diciembre de 2018. Se consideraron para el análisis el porcentaje de implantes oseointegrados y su relación con el tipo de operador (docente o residente), la situación del reborde óseo y el hábito de fumar. Resultados: De los 176 implantes colocados en 88 pacientes (edad promedio = 67 años), a los 3-4 meses el 98% (IC95: 94-99%) se hallaba oseointegrado. No se encontró una relación estadísticamente significativa entre el tipo de operador y el fracaso (P>0,99) Conclusión: En un servicio de formación, la tasa de éxito, evaluada en la segunda cirugía, de dos implantes dentales colocados en el maxilar inferior para sobredentaduras fue de 98%. No se hallaron diferencias entre los resultados logrados por residentes y docentes del servicio (AU)

Aim: To evaluate the percentage of osseointegrated im- plants placed in edentulous patients to restore with mandib- ular overdentures, within the post graduate dental training framework. Materials and methods: Medical records of patients who received two dental implants in the mandible for the placement of overdentures in the resident clinic of the special- ization career in Oral and Maxillofacial Surgery and Trauma- tology from the Facultad de Odontología de la Universidad de Buenos Aires, between August 2012 and December 2018. The percentage of osseointegrated implants was analysed, and the association with the variables: operator (teacher or resident), mediate or immediate placement, and smoking. Results: 176 implants were placed in 88 patients with an average age of 67 years old. 98% (IC95: 94-99%) of the implants were osseointegrated at 3-4 months. No statistically significant association was detected between the type of oper- ator and implant failure (P>0.99). Conclusion: In the teaching dental training clinic, the success rate, evaluated at the second implant stage surgery, of two dental implants placed in the mandibule for overden- tures was 98%. No differences were found between the results achieved by residents and teachers (AU)

Postsynthetic Metalated MOFs as Atomically Dispersed Catalysts for Hydroformylation Reactions.

A manganese-based metal-organic framework with dipyrazole ligands has been metalated with atomically dispersed Rh and Co species and used as a catalyst for the hydroformylation of styrene. The Rh-based materials exhibited excellent conversion at 80 °C with complete chemoselectivity, high selectivity for the branched aldehyde, high recyclability, and negligible metal leaching.

A DVD-MoS2/Ag2S/Ag Nanocomposite Thiol-Conjugated with Porphyrins for an Enhanced Light-Mediated Hydrogen Evolution Reaction.

We have recently demonstrated in a previous work an appreciable photoelectrocatalytic (PEC) behavior towards hydrogen evolution reaction (HER) of a MoS2/Ag2S/Ag nanocomposite electrochemically deposited on a commercial writable Digital Versatile Disc (DVD), consisting therefore on an interesting strategy to convert a common waster product in an added-value material. Herein, we present the conjugation of this MoS2/Ag2S/Ag-DVD nanocomposite with thiol-terminated tetraphenylporphyrins, taking advantage of the grafting of thiol groups through covalent S-S bridges, for integrating the well-known porphyrins photoactivity into the nanocomposite. Moreover, we employ two thiol-terminated porphyrins with different hydrophilicity, demonstrating that they either suppress or improve the PEC-HER performance of the overall hybrid, as a function of the molecule polarity, sustaining the concept of a local proton relay. Actually, the active polar porphyrin-MoS2/Ag2S/Ag-DVD hybrid material presented, when illuminated, a better HER performance, compared to the pristine nanocomposite, since the porphyrin may inject photoelectrons in the conduction band of the semiconductors at the formed heterojunction, presenting also a stable operational behavior during overnight chopped light chronoamperometric measurement, thanks to the robust bond created.

Noncovalent Integration of a Bioinspired Ni Catalyst to Graphene Acid for Reversible Electrocatalytic Hydrogen Oxidation.

Efficient heterogeneous catalysis of hydrogen oxidation reaction (HOR) by platinum group metal (PGM)-free catalysts in proton-exchange membrane (PEM) fuel cells represents a significant challenge toward the development of a sustainable hydrogen economy. Here, we show that graphene acid (GA) can be used as an electrode scaffold for the noncovalent immobilization of a bioinspired nickel bis-diphosphine HOR catalyst. The highly functionalized structure of this material and optimization of the electrode-catalyst assembly sets new benchmark electrocatalytic performances for heterogeneous molecular HOR, with current densities above 30 mA cm-2 at 0.4 V versus reversible hydrogen electrode in acidic aqueous conditions and at room temperature. This study also shows the great potential of GA for catalyst loading improvement and porosity management within nanostructured electrodes toward achieving high current densities with a noble-metal free molecular catalyst.

Randomized Clinical Trial Comparing Three Local Hemostatic Agents for Dental Extractions in Patients under Chronic Anticoagulant Therapy - A Comparative Study.

INTRODUCTION: Oral anticoagulants are widely used worldwide for many systemic diseases. Recent oral surgical protocols suggest that therapeutic levels of the anticoagulant drug should be maintained for simple dental extractions because bleeding complications could be managed with proper local hemostasis. The aim of the present study was to compare bleeding complication of three different local hemostatic agents for dental extractions without interrupting drug administration in patients undergoing oral Vitamin K antagonist chronic anticoagulant therapy. MATERIAL AND METHODS: Randomized control trial of three hemostatic agents for dental extractions, in patients under oral anticoagulant therapy without drug interruption. The present study included 240 patients with international normalized ratio between 1.5 and 3.5. Patients took their anticoagulation drug normally. A single surgeon performed calibrated simple dental extractions and applied a plug of bismuth subgallate (BS), fibrin tissue adhesive (FTA) or microfibrillar collagen (MC), assigned randomly. Statistical analysis of bleeding between the groups was performed using the Chi-square test. RESULTS: There was no hemorrhagic complication in the BS group, and only one in the FTA group. However, in the MC group, 10 patients (12.5%) suffered postoperative bleeding. Data analysis showed statistical differences between the MC group and the other two groups (P < 0.05). DISCUSSION: BS and FTA showed similar clinical effectiveness and were more effective than MC for the control of postoperative bleeding in oral anticoagulated patients.

Combined high degree of carboxylation and electronic conduction in graphene acid sets new limits for metal free catalysis in alcohol oxidation.

Graphene oxide, the most prominent carbocatalyst for several oxidation reactions, has severe limitations due to the overstoichiometric amounts required to achieve practical conversions. Graphene acid, a well-defined graphene derivative selectively and homogeneously covered by carboxylic groups but maintaining the high electronic conductivity of pristine graphene, sets new activity limits in the selective and general oxidation of a large gamut of alcohols, even working at 5 wt% loading for at least 10 reaction cycles without any influence from metal impurities. According to experimental data and first principles calculations, the selective and dense functionalization with carboxyl groups, combined with excellent electron transfer properties, accounts for the unprecedented catalytic activity of this graphene derivative. Moreover, the controlled structure of graphene acid allows shedding light upon the critical steps of the reaction and regulating precisely its selectivity toward different oxidation products.

Mixoma de válvula mitral. El ecocardiograma como herramienta de caracterización tisular. Reporte de caso / Mitral valve myxoma. The echocardiogram as a tissue characterization tool. A case report

Resumen: Compartimos el caso de un paciente de 32 años que se presentó con síndrome coronario agudo con elevación del ST en cara inferior y cineangiocoronariografía sin lesiones coronarias, a quien se le diagnosticó mediante ecocardiografía la presencia de un tumor en la válvula mitral. Mediante técnicas de caracterización tisular se arribó al diagnóstico presuntivo de mixoma que fue confirmado por la anatomía patológica.

Summary: We share the case of a 32-year-old patient who presented with inferior infarction and no coronary lesions at coronariography, in whom the presence of a tumor in the mitral valve was diagnosed by echocardiography. Through tissular characterization techniques, we arrived at a presumptive myxoma diagnosis, which was confirmed by pathological anatomy.

A randomized controlled trial comparing nerve block and mandibular infiltration techniques in posterior mandible implant surgeries.

BACKGROUND: To compare global surgical pain under nerve block and mandibular infiltration anesthesia techniques, and to evaluate pain during drilling and the distance to the mandibular canal in posterior mandible implant surgeries. MATERIAL AND METHODS: A prospective, randomized, controlled, double-blind, clinical trial was conducted to compare nerve block (Group A) to mandibular infiltration (Group B) techniques for dental implant placement. Global surgical pain (VAS = visual analogue scale), pain during drilling or implant placement (MPQ = McGill pain questionnaire) and distance to the mandibular canal (Image J) were statically analyzed. Age, gender, anxiety levels, tooth to be replaced, implant size, adjacent teeth and duration of surgery were also analyzed. RESULTS: 172 patients were included and 283 dental implants were analyzed. VAS values were significantly higher in Group B (p<0.05). In Group A, 99% of the surgeries were performed painlessly during drilling and implant placement, but in Group B, 11.6% of implant placements (17 implants) felt pain during these surgical steps. Mean distance to mandibular canal (3.8 mm, range: 0.0 to 7.0) in those 17 implants placed under mandibular infiltration was clinically and statistically similar to the mean distance (3.0 mm, range: 0.0 to 9.0) of 130 implants placed painless (p=0.10). Pain during drilling under mandibular infiltration was significantly associated with the duration of surgery (p<0.05) and to both adjacent teeth being present (p<0.05). CONCLUSIONS: Although both techniques are safe and effective for placing implants in the posterior mandible, nerve block provides a more profound analgesia than mandibular infiltration. When placing implants under mandibular infiltration, as getting closer to the canal does not increase the feeling of pain, it is not recommended to use the presence of pain as a preventive resource to avoid inferior alveolar nerve injuries. Key words:Dental implant, mandibular infiltration anesthesia, nerve block, pain, nerve injury.