Random number generator based on a memristive circuit.

In this paper we discuss the details, limitations, and difficulties of the implementation in hardware of a memristor-based random number generator that exhibits monofractal/multifractal behavior. To do so, the components and selection criteria of a reference memristor and one proposed by the authors, the chaotic circuit leveraging them, and the processing that is performed on the chaotic signals to achieve the random discrete sequences are described. After applying the estimation tools, findings indicate that more than 60% of the proposed combinations allow generating random discrete sequences, with long-range dependence, and that both monofractal and multifractal behaviors can also be obtained. Consequently, a hardware system was achieved that can be used as a source of entropy in future synthetic biological signal generators.

Principios físicos y avances recientes de la termografía infrarroja en odontología

RESUMEN Introducción: El calor resultante de los procesos metabólicos celulares puede medirse mediante termografía infrarroja, especialmente en células con alto consumo de energía como las musculoesqueléticas. En odontología, los cambios térmicos pueden indicar anomalías o trastornos musculares. Se realizó una búsqueda de información científica en las bases de datos PubMed, SciELO, Redalyc, entre otras, de 2015 a 2020, en inglés y español. Objetivo: Describir los principios físicos y los avances más recientes de la termografía infrarroja en odontología, relacionados con trastornos temporomandibulares, el dolor pediátrico, aplicaciones en implantología y endodoncia. Desarrollo: Se encontraron varias aplicaciones de la termografía en odontología: i) trastornos temporomandibulares, ii) en el diagnóstico del lupus eritematoso, iii) en implantología, iv) endodoncia y v) dolor en odontopediatría. Sobre i) y ii) en la literatura consultada se obtuvieron resultados que respaldaban la eficacia de la termografía infrarroja como un examen diagnóstico complementario, sobre todo en mujeres. Respecto a iii) y iv) la termografía infrarroja mostró ser efectiva como método para evaluar los cambios térmicos en procedimientos como la preparación de la zona del implante y en la técnica de condensación vertical. Finalmente, en v), la TIR parece útil para la detección el nivel de dolor en niños. Conclusión: La termografía infrarroja es una herramienta diagnóstica con potencial de detección de anomalías que inducen cambios térmicos, además de ser un excelente método para detectar las altas temperaturas en diversos procedimientos odontológicos, que sin el debido cuidado puede llevar al fracaso del tratamiento.

ABSTRACT Introduction: The heat resulting from cellular metabolic processes can be measured by infrared thermography, especially in cells with high energy consumption such as musculoskeletal cells. In dentistry, thermal changes can indicate muscle abnormalities or disorders. A search for scientific information was carried out in databases PubMed, SciELO, Redalyc, among others, from 2015 to 2020, in English and Spanish. Objective: To describe the physical principles and the most recent advances of infrared thermography in dentistry, related to temporomandibular disorders; pediatric pain; applications in implantology and endodontics. Development: Several applications of thermography were found in dentistry: i) temporomandibular disorders, ii) in the diagnosis of lupus erythematosus, iii) in implantology, iv) endodontics and v) pain in pediatric dentistry. Regarding i) and ii) in the consulted literature, results were obtained that supported the efficacy of Infrared Thermography as a complementary diagnostic test, especially in women. Regarding iii) and iv) Infrared Thermography proved to be effective as a method to evaluate thermal changes in procedures such as the preparation of the implant area and in the vertical condensation technique. Finally, in v), the Infrared Thermography seems useful for detecting the level of pain in children. Conclusion: Infrared thermography is a diagnostic tool with the potential to detect anomalies that induce thermal changes, as well as being an excellent method to detect high temperatures in various dental procedures that, without due care, can lead to treatment failure.

Cention-N: una opción restaurativa directa e innovadora para el sector posterior

RESUMEN Introducción: La industria odontológica está en constante evolución respecto a la concreción de materiales dentales que mejoren la calidad de vida. Sin embargo, debido al gran número de estos, es imprescindible realizar comparaciones de propiedades biomecánicas que definan los de mejor rendimiento. Objetivo: Identificar las ventajas y desventajas del material de restauración Cention-N, con respecto a la resina compuesta, el ionómero de vidrio y la amalgama. Métodos: Se hizo una investigación bibliográfica en las bases PubMed, Scielo, Semantic Scholar, ScienceDirect, Medigraphyc y Redalyc. Se usaron como palabras clave: Cention-N, material restaurativo, amalgama, resina compuesta, el ionómero de vidrio; combinadas con operadores booleanos AND y OR. Se seleccionaron artículos originales y de revisión, entre otros documentos, para examinar 4 características: microfiltración, dureza, rugosidad superficial y resistencia al cizallamiento. El 50 % de los artículos escogidos se publicaron en los últimos 5 años. Resultados: Se seleccionaron un total de 13 artículos, 1 página web y 1 libro, acorde con los filtros de selección y objetivo de investigación. El Cention-N, con respecto a los demás materiales considerados, presentó menor puntuación de microfiltración (0,28 ± 0,18), mayor dureza (77 N/mm2), menor rugosidad (442,98 ± 62,45 nm) y mayor resistencia al cizallamiento (14,38 ± 3,88 MPa). Resta evaluar sus propiedades mecánicas ante procedimientos abrasivos como el blanqueamiento dental y a cargas altas como en el bruxismo. Conclusión: Cention-N es una opción prometedora como material restaurador del sector posterior al evidenciar una menor microfiltración y rugosidad; así como mayor resistencia al cizallamiento y dureza, en comparación con otros materiales restaurativos estudiados.

ABSTRACT Introduction: Dental industry is constantly evolving regarding the realization of dental materials that improve the quality of life. However, due to the large number of these, it is essential to perform intercomparisons of biomechanical properties that define those with the best performance. Objective: To identify the advantages and disadvantages of Cention-N restorative material with respect to composite resin, glass ionomer and amalgam. Methods: A bibliographic search was made in the PubMed, Scielo, Semantic Scholar, ScienceDirect, Medigraphyc and Redalyc databases. The following keywords were used: Cention-N, restorative material, amalgam, composite resin, the glass ionomer; combined with Boolean AND and OR operators. Original and review articles, among other documents, were chosen to examine 4 characteristics: microfiltration, hardness, surface roughness and shear resistance. 50% of the articles are from the last 5 years. Results: A total of 13 articles, 1 webpage and 1 book, were found according to the selection filters and research objective. The Cention-N, with respect to the other materials considered, presented a lower microfiltration score (0,28 ± 0,18); higher hardness (77 N/mm2); lower roughness (442,98 ± 62,45 nm) and higher shear strength (14,38 ± 3,88 MPa). However, it remains to evaluate its mechanical properties before abrasive procedures such as teeth whitening and at high loads such as bruxism. Conclusion: Cention-N is a promising option as a posterior sector restorative material as it shows less microfiltration and roughness; as well as greater resistance to shear and hardness, compared to other restorative materials studied.

Leadless Cardiac Devices-Pacemakers and Implantable Cardioverter-Defibrillators.

OPINION STATEMENT: Since the initial introduction of pacemakers and defibrillators, the rapid growth in microcircuit and battery technology has increased the longevity demands and exposed the vulnerabilities of transvenous leads. Over a half of century later, leadless pacemaker and defibrillation systems are just reaching the clinical arena. Despite the remarkable advantages of leadless pacing systems, the data are still quite limited and broad implementation of these technologies need to occur in a cautious and deliberate fashion as the peri-procedural risks remains high. Two of the three systems, Nanostim(TM) (St. Jude Medical) and Micra Transcatheter Pacing System (Medtronic Inc.), have shown the greatest applicability, although they are currently only limited to single chamber pacing and procedural risks are modest. The WiCS(TM)-LV system (EBR Systems, Inc.) is anatomically limited and benefits a small subset of patients. Leadless implantable cardioverter-defibrillator (ICD) therapy, the subcutaneous ICD (S-ICD, Cameron Health/Boston Scientific), has demonstrated encouraging short-term safety and efficacy data supporting its use. Since its introduction, modifications to the implant procedure, pre-screening of patients, and programming of the devices have reduced procedural-related complications and inappropriate shocks. The S-ICD is a promising technology, but it is premature to conclude that it will supplant conventional ICDs. At this current time, the S-ICD may benefit select patients, such as those with recurrent bacteremia, vascular access limitations, and who may be prone to transvenous lead failure.