Integrated photon pairs source in silicon carbide based on micro-ring resonators for quantum storage at telecom wavelengths.

We present the design of an on-chip integrated photon pair source based on Spontaneous Four Wave Mixing (SFWM), implemented on a ring resonator in the 4H Silicon Carbide On Insulator (4H-SiCOI) platform, compatible with a solid state quantum memory in the telecommunications band. Through careful engineering of the waveguide dispersion and micro-ring resonator dimensions, we found solutions where the signal photons are emitted at 1536.48 nm with a bandwidth of ∼ 150 MHz, enabling the interaction with the hyperfine structure of Er 3 + ions. Simultaneously, the idler photons are generated at 1563.86 nm, matching the central wavelength of a specific channel in a commercial dense wavelength division multiplexing system. The proposed device fulfill all the spectral requirements in a simple ring-bus coupled waveguide configuration with design parameters within the range of reported values for similar resonators, making feasible its manufacturing with current fabrication capabilities.

Integrated photon pair source based on a silicon nitride micro-ring resonator for quantum memories.

We report the design of an integrated photon pair source based on spontaneous four-wave mixing (SFWM), implemented in an integrated micro-ring resonator in the silicon nitride platform (Si3N4). The signal photon is generated with emission at 606 nm and bandwidth of 3.98 MHz, matching the spectral properties of praseodymium ions (Pr), while the idler photon is generated at 1430.5 nm matching the wavelength of a CWDM channel in the E-band. This novel, to the best of our knowledge, device is designed to interact with a quantum memory based on a Y2SiO5 crystal doped with Pr3+ ions, in which we used cavity-enhanced SFWM along with dispersion engineering to reach the required wavelength and the few megahertz signal photon spectral bandwidth.

Waterborne Antifouling Paints Containing Nanometric Copper and Silver against Marine Bacillus Species.

Due to the concern to find an alternative to reduce the colonization (microfouling and macrofouling) or the biocorrosion of surfaces submerged for long periods in water, we evaluated the antifouling activity of a commercial paint added with silver nanoparticles (AgNP's) and copper nanoparticles (CuNP's), beside copper-soybean chelate, by electrolytic synthesis, using them in low concentrations (6.94E - 04 mg Ag g-1 paint, 9.07E - 03 mg Cu g-1 paint, and 1.14E - 02 mg Cu g-1 paint, respectively). The test for paint samples was carried out by JIS Z2801-ISO 22196 for periods of initial time, 6 months, and 12 months, against three bacterial strains of marine origin, Bacillus subtilis, Bacillus pumilus, and Bacillus altitudinis. It was possible to demonstrate, according to the standard, that the sample with the greatest antimicrobial activity was the copper-soybean chelate against two of the three strains studied (B. pumilus with R = 2.11 and B. subtilis with R = 2.41), which represents more than 99% of bacterial inhibition. Therefore, we considered a novel option for inhibiting bacterial growth with nanoparticles as antifouling additives.

Biopelículas bacterianas en heridas crónicas / Bacterial biofilms in chronic wounds / Biopeliculas bacterianas em feridas crónicas

En las últimas tres décadas, el estudio de las biopelículas bacterianas ha tomado gran relevancia gracias a su identificación como uno de los factores más importantes en el desarrollo de infecciones crónicas. Una de las patologías de mayor interés en el área de la salud, y de la cual se ha logrado profundizar en mayor medida, corresponde a las heridas crónicas, en donde se estima que las biopelículas bacterianas están presentes en el 60%, comparadas con las heridas agudas en donde se presentan solo en el 20%.Las heridas crónicas representan el 1-2% de todas las heridas a nivel mundial, pero la carga socioeconómica y emocional que generan, repercute notablemente debido a los costos en curaciones, tratamientos convencionales y en complicaciones tan graves como las amputaciones de extremidades. El objetivo de este artículo de revisión es proporcionar información relevante sobre el concepto de las biopelículas bacterianas, su implicación en el desarrollo de heridas crónicas, el diagnóstico y los posibles tratamientos

In the last decades, the study of bacterial biofilms has become relevant due to its significance in the development of chronic infections. Chronic wounds constitute a disease that holds great interest for health care. It is estimated that bacterial biofilms are present in 60% of chronic wounds as opposed to acute wounds in which the presence of bacterial biofilms is 20%. Chronic wounds account for 1% to 2% of all injuries worldwide but socioeconomic and emotional burden plays a major role in healing costs; traditional treatments and severe complications such limb amputations. The aim of the present review article is to provide relevant information on the concept of bacterial biofilms, its implication in the development of chronic wounds, its diagnosis and prospective treatments.

Resumo. Ao longo das últimas três décadas, o estudo das biopeliculas bacterianas tem tido grande relevância pela identificação de um dos fatores mais importantes no desenvolvimento de infeções crónicas. Uma das patologias de maior interesse na área da saúde, são as feridas crónicas, as biopeliculas bacterianas estão presentes em aproximadamente 60% (enquanto nas feridas agudas só se apresentam em aproximadamente 20% dos casos). Embora mundialmente as feridas crônicas representam entre 1 e 2% do total das feridas, a carga emocional e econômica que elas implicam, tem grande repercussão, chegando nos piores casos à amputação. O objetivo do presente artigo é proporcionar informação clara a respeito deste tema.

Antimicrobial Properties of Copper Nanoparticles and Amino Acid Chelated Copper Nanoparticles Produced by Using a Soya Extract.

This paper reports a comparison of the antibacterial properties of copper-amino acids chelates and copper nanoparticles against Escherichia coli, Staphylococcus aureus, and Enterococcus faecalis. These copper-amino acids chelates were synthesized by using a soybean aqueous extract and copper nanoparticles were produced using as a starting material the copper-amino acids chelates species. The antibacterial activity of the samples was evaluated by using the standard microdilution method (CLSI M100-S25 January 2015). In the antibacterial activity assays copper ions and copper-EDTA chelates were included as references, so that copper-amino acids chelates can be particularly suitable for acting as an antibacterial agent, so they are excellent candidates for specific applications. Additionally, to confirm the antimicrobial mechanism on bacterial cells, MTT assay (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) was carried out. A significant enhanced antimicrobial activity and a specific strain were found for copper chelates over E. faecalis. Its results would eventually lead to better utilization of copper-amino acids chelate for specific application where copper nanoparticles can be not used.

Academic achievement and perception of two teaching methods in histology: light microscopy and digital systems / Rendimiento académico y percepción de dos métodos de enseñanza en histología: microscopía óptica y sistema digital

With the advent of digital systems, the role of the microscope as an irreplaceable instrument in the practical teaching of histology has been called into question. In this study academic performance and student perception for three learning methods was compared: digital systems, microscopy, and microscopy plus digital systems, in the muscle tissue unit of the morphology course for first-year dentistry at the Universidad de los Andes, Santiago, Chile. Ninety-five students were divided into 3 groups: Group 1: individual optical microscopy, Group 2: digital systems (one projector per room), and Group 3: microscopy plus digital systems. All participants observed the same striate muscle, cardiac striated muscle, and smooth muscle mounts. Their diagnostic capacity was evaluated. A perception test was conducted after everyone had learned with both systems. For data analysis the Kruskal-Wallis test and logistic regression were used. In the cognitive evaluation, the median grades were 4.5 for group 2 and 5.45 for group 3 (Kruskal-Wallis p-value= 0.0023). In the perception survey, 69% of students reported feeling motivated by the use of the microscope and 51% reported that they felt motivated by the use of digital system (p-value= 0.0016). It was concluded that the combined use of optical microscopy and digital systems achieves better performance as compared to the digital system alone. The use of the microscope improves student perception as compared to those using only the digital system.

Con el advenimiento de los sistemas digitales, se ha puesto en tela de juicio el rol del microscopio como instrumento insustituible para la enseñanza práctica de la histología. El objetivo fue comparar el rendimiento académico y la percepción de los alumnos utilizando tres métodos de aprendizaje: sistema digital, microscopía y microscopía más sistema digital, en la unidad de tejido muscular del curso de morfología de primer año de Odontología de la Universidad de los Andes. Noventa y cinco alumnos fueron divididos en 3 grupos: 1: microscopía óptica individual, 2: sistema digital (proyección única en sala) y 3: microscopía más sistema digital. Todos observaron los mismos preparados de músculo estriado esquelético, estriado cardiaco y liso. Al finalizar, rindieron una evaluación cognitiva y luego los grupos fueron invertidos. Una vez que todos aprendieron con ambos sistemas realizaron una encuesta de percepción. Para el análisis de datos se utilizaron los test de Kruskall-wallis y Regresión Logística. En la evaluación cognitiva, el grupo 3 resultó ser significativamente superior a las del grupo 2 (Kruskall-wallis P= 0,0023). En la encuesta de percepción el 69% de los alumnos expresaron sentirse motivados por el uso del microscopio y un 51% respondieron que se sintieron motivados con el uso de sistema digital (p= 0,0016). En conclusión, el uso combinado de microscopía más sistema digital obtuvo mejores resultados que el sistema digital solo, y el uso de microscopio obtuvo una mejor percepción comparada entre quienes usaron únicamente el sistema digital.

Evaluación de la proliferación de células madres mesenquimales estimuladas con diferentes intensidades de ultrasonido de baja intensidad / Evaluation of mesenchymal stem cell proliferation using different low intensity pulsed ultrasound intensities

Las células madres mesenquimales (CMM) pueden ser afectadas en su capacidad de proliferar in vitro bajo estimulación física o bioquímica, siendo esta una capacidad esencial para un adecuado cultivo celular. Un método de estimulación física que ha demostrado ser eficiente en este sentido es el Ultrasonido pulsátil de baja intensidad (USBI), aplicado en intensidades iguales o inferiores a 100 mW/cm2, habitualmente entre 30 y 50 mW/cm2. El objetivo de esta investigación fue determinar el nivel de intensidad de ultrasonido pulsátil de baja intensidad óptimo entre 30 y 50 mW/cm2 para estimular la proliferación de CMM de médula ósea de ratas Sprague Dawley, in vitro. CMM (1x106cls/kg) de medula ósea de rata Sprague-Dawley fueron cultivadas (alfa-MEM, 20 por ciento FBS y 1 por ciento antibiotico) y estimuladas con USBI (0,02 milisegundos), por 20 minutos dos veces al día por 10 días con intensidades de 0, 30 y 50 mW/cm2 (grupos A [control], B, C respectivamente). Se contabilizó el número de células en el cultivo y se evaluó morfología celular en microscopio óptico. Se utilizaron tests de ANOVA on Ranks y Bonferroni. Los cultivos estimulados con USBI presentaron mayores recuentos celulares, y se observaron diferencias estadísticamente significativas entre los grupos A y C (p<0,05). Se observaron diferencias morfológicas entre células de grupos estimulados con USBI y el control. La estimulación de las CMM en cultivos bidimensionales con USBI influencia cambios en la morfología celular y se concluye que 50mW/cm2 es la intensidad óptima dentro de las evaluadas para producir aumento en la proliferación celular (p<0.05).

Mesenchymal stem cells (MSCs) can be affected in their capabilities to proliferate in vitro under physical and/or biochemical stimulation. The aim of this study was to select an optimal intensity level for low intensity pulsed ultrasound (LIPUS) stimulation of Sprague-Dawley bone marrow MSCs proliferation in vitro. Bone marrow MSCs of Sprague-Dawley rats where cultured (a-MEM, 20 percent FBS and 1 percent antibiotic) and stimulated with LIPUS (0,02 milisec), for 20 minutes twice daily for 10 days, at intensities of 0 (control), 30 and 50mW/cm2 (groups A, B, C). Cellular count and morphological evaluation were performed. ANOVA and Bonferroni tests were performed. LIPUS-stimulated cultures displayed greater cellular counts, and significant differences were observed between groups A and C (p<0,05). Morphological differences were observed between cells from LIPUS-stimulated and control groups. An intensity of 50mW/cm2 elicits increased cellular proliferation (p<0.05). Stimulation of MSCs cultures with LIPUS influences cellular morphology.

Deuterium anions in inertial electrostatic confinement devices.

A magnetic deflection-energy analyzer and Faraday trap diagnostic have been used to make measurements of divergent deuterium anion flow in the inertial electrostatic confinement experiment at the University of Wisconsin-Madison (UW-IEC) [J. F. Santarius, G. L. Kulcinski, R. P. Ashley, D. R. Boris, B. B. Cipiti, S. K. Murali, G. R. Piefer, R. F. Radel, I. E. Radel, and A. L. Wehmeyer, Fusion Sci. Technol. 47, 1238 (2005)], a device to confine high-energy light ions in a spherically symmetric electrostatic potential well. Deuterium anion current densities as high as 8.5 microA/cm2 have been measured at the wall of the UW-IEC device, 40 cm from the surface of the device cathode with a detector assembly of admittance area 0.7 cm2. Energy spectra obtained using a magnetic deflection-energy analyzer diagnostic indicate the presence of D2(-), and D- ions produced through thermal electron attachment near the device cathode, as well as D- ions produced via charge-transfer processes between the anode and cathode of the device.

Transplantation of GABAergic neurons but not astrocytes induces recovery of sensorimotor function in the traumatically injured brain.

Embryonic stem (ES) cells have been investigated in many animal models of injury and disease. However, few studies have examined the ability of pre-differentiated ES cells to improve functional outcome following traumatic brain injury (TBI). The purpose of the present study was to compare the effect of murine ES cells that were pre-differentiated into GABAergic neurons or astrocytes on functional recovery following TBI. Neural and astrocyte induction was achieved by co-culturing ES cells on a bone marrow stromal fibroblast (M2-10B4) feeder layer and incubating them with various mitogenic factors. Rats were initially prepared with a unilateral controlled cortical contusion injury of the sensorimotor cortex or sham procedure. Rats were transplanted 7 days following injury with approximately 100K GABAergic neurons, astrocytes, fibroblasts, or media. Animals were assessed on a battery of sensorimotor tasks following transplantation. The stromal fibroblast cells (M2-10B4), as a control cell line, did not differ significantly from media infusions. Transplantation of GABAergic neurons facilitated complete and total recovery on the vibrissae-forelimb placing test as opposed to all other groups, which failed to show any recovery. It was also found that GABAergic neurons reduced the magnitude of the initial impairment on the limb use test. Histological analysis revealed infiltration of host brain with transplanted neurons and astrocytes. The results of the present study suggest that transplantation of pre-differentiated GABAergic neurons significantly induces recovery of sensorimotor function; whereas, astrocytes do not.

Transplantation of neuronal and glial precursors dramatically improves sensorimotor function but not cognitive function in the traumatically injured brain.

Embryonic stem (ES) cells have been investigated in various animal models of neurodegenerative disease; however, few studies have examined the ability of ES cells to improve functional outcome following traumatic brain injury (TBI). The purpose of the present study was to examine the ability of pre-differentiated murine ES cells (neuronal and glial precursors) to improve functional outcome. Rats were prepared with a unilateral controlled cortical impact injury or sham and then transplanted 7 days later with 100K ES cells (WW6G) (~30% neurons) or media. Two days following transplantation rats were tested on a battery of behavioral tests. It was found that transplantation of ES cells improved behavioral outcome by reducing the initial magnitude of the deficit on the bilateral tactile removal and locomotor placing tests. ES cells also induced almost complete recovery on the vibrissae --> forelimb placing test, whereas, media-transplanted rats failed to show recovery. Acquisition of a reference memory task in the Morris water maze was not improved by transplantation of ES cells. Histological analysis revealed a large number of surviving ES cells in the lesion cavity and showed migration of ES cells into subcortical structures. It was found that transplantation of ES cells prevented the occurrence of multiple small necrotic cavities that were seen in the cortex adjacent to the lesion cavity in media transplanted rats. Additionally, ES cells transplants also significantly reduced lesion size. Results of this study suggest that ES cells that have been pre-differentiated into neuronal precursors prior to transplantation have therapeutic potential.

Supercritical fluid chromatography in drug analysis: a literature survey.

The applications of supercritical fluid chromatography to the analysis of drugs have been carefully revised from the literature compiled in the Analytical Abstracts until March 1994. Easy-to-read tables provide useful information about the state-of-the-art and possibilities offered by SFC in pharmaceutical analysis. The tables comprise extensive data about samples analyzed, pharmaceutical principles determined, solvents used and sample quantity injected, supercritical fluids and modifiers employed, injection system, instrumentation, experimental conditions for chromatographic separations (density, pressure, flow, temperature), characteristics of columns employed (type, support, length, diameter, particle film thickness, stationary phase), detectors, type of restrictors, and also some analytical features of the methods developed (such as retention time, resolution, sensitivity, limit of detection and relative standard deviation).

Prueba de inclinación en la evaluación del síncope o presíncope de etiología no precisada en niños y adolescentes / Head-up tilt test in clinical evaluation of unexplained etiology syncope or presyncope in children and adolescents

El síncope y el presíncope recurrentes y de etiología no precisada son problemas relativamente frecuentes en niños y, en general, de difícil evaluación. En adultos, la prueba de inclinación permite reproducir los síntomas y algunos de los mecanismos hemodinámicos asociados en 30 a 75 por ciento de los casos. Se describen las respuestas hemodinámicas durante la prueba de inclinación a 70º en 26 pacientes consecutivos menores de 19 años de edad, referidos a nuestro centro por dicho problema en un período de dos años. Se obtuvieron respuestas positivas en 50 por ciento de los casos, en la mayoría de ellos se utilizando isoproterenol (dosis promedio 3,1 ñ 0,4µg/min), con incremento promedio de la frecuencia cardíaca de 41 por ciento. La presión arterial sistólica disminuyó significativamente, hasta menos de 70 mmHg, en todos los pacientes con respuesta positiva. También disminuyó la frecuencia cardíaca, lo que rara vez fue acentuado, al momento de hacerse positivo el examen. La hipotensión arterial fue simultánea o precedió a la braquicardia. En todos los casos positivos se reprodujeron los síntomas que motivaron la consulta. Esta prueba puede ser de importancia en el estudio diagnóstico del síncope de cauda no precisada en niños y adolescentes y, al reproducir los síntomas asociados, permite precisar los mecanismos hemodinámicos participantes en aproximadamente el 50 por ciento de estos pacientes

A classification of precision attachments.

This overview of attachments is intended to provide an explanation of the design characteristics of 13 different groups. The clinical situation for which an attachment is intended will place specific demands that can be met more closely if the forces acting on the prosthesis are considered. No universal or ideal design is available, so if attachments are used, they should be selected from the group with the most suitable characteristics for the task required. The stress-breaking effect of attachments is vague. They offer a potential for rotational and resilient movement between the prosthesis and the abutment teeth, but the amount of stress that must be broken to protect the periodontium of the teeth may exceed the capabilities of any particular attachment used. Nevertheless, attachments can provide an effective answer to prosthesis stability and retention in a way that is cosmetically pleasing.