RESUMEN
Broken time-reversal symmetry in the absence of spin order indicates the presence of unusual phases such as orbital magnetism and loop currents1-4. The recently discovered kagome superconductors AV3Sb5 (where A is K, Rb or Cs)5,6 display an exotic charge-density-wave (CDW) state and have emerged as a strong candidate for materials hosting a loop current phase. The idea that the CDW breaks time-reversal symmetry7-14 is, however, being intensely debated due to conflicting experimental data15-17. Here we use laser-coupled scanning tunnelling microscopy to study RbV3Sb5. By applying linearly polarized light along high-symmetry directions, we show that the relative intensities of the CDW peaks can be reversibly switched, implying a substantial electro-striction response, indicative of strong nonlinear electron-phonon coupling. A similar CDW intensity switching is observed with perpendicular magnetic fields, which implies an unusual piezo-magnetic response that, in turn, requires time-reversal symmetry breaking. We show that the simplest CDW that satisfies these constraints is an out-of-phase combination of bond charge order and loop currents that we dub a congruent CDW flux phase. Our laser scanning tunnelling microscopy data open the door to the possibility of dynamic optical control of complex quantum phenomenon in correlated materials.
Asunto(s)
Superconductividad , Microscopía de Túnel de Rastreo , Campos Magnéticos , Fonones , Electrones , LuzRESUMEN
The bottom-up fabrication of supramolecular and self-assembly on various substrates has become an extremely relevant goal to achieve prospects in the development of nanodevices for electronic circuitry or sensors. One of the branches of this field is the self-assembly of functional molecular components driven through non-covalent interactions on the surfaces, such as van der Waals (vdW) interactions, hydrogen bonding (HB), electrostatic interactions, etc., allowing the controlled design of nanostructures that can satisfy the requirements of nanoengineering concepts. In this context, non-covalent interactions present opportunities that have been previously explored in several molecular systems adsorbed on surfaces, primarily due to their highly directional nature which facilitates the formation of well-ordered structures. Herein, we review a series of research works by combining STM (scanning tunneling microscopy) with theoretical calculations, to reveal the processes used in the area of self-assembly driven by molecule Landers equipped with functional groups on the metallic surfaces. Combining these processes is necessary for researchers to advance the self-assembly of supramolecular architectures driven by multiple non-covalent interactions on solid surfaces.
Asunto(s)
Nanoestructuras , Propiedades de Superficie , Nanoestructuras/química , Microscopía de Túnel de Rastreo , Enlace de Hidrógeno , Electricidad Estática , Adsorción , Nanotecnología/métodosRESUMEN
The combination of low-temperature scanning tunnelling microscopy with a mass-selective electro-spray ion-beam deposition established the investigation of large biomolecules at nanometer and sub-nanometer scale. Due to complex architecture and conformational freedom, however, the chemical identification of building blocks of these biopolymers often relies on the presence of markers, extensive simulations, or is not possible at all. Here, we present a molecular probe-sensitisation approach addressing the identification of a specific amino acid within different peptides. A selective intermolecular interaction between the sensitiser attached at the tip-apex and the target amino acid on the surface induces an enhanced tunnelling conductance of one specific spectral feature, which can be mapped in spectroscopic imaging. Density functional theory calculations suggest a mechanism that relies on conformational changes of the sensitiser that are accompanied by local charge redistributions in the tunnelling junction, which, in turn, lower the tunnelling barrier at that specific part of the peptide.
Asunto(s)
Aminoácidos , Sondas Moleculares , Péptidos/química , Secuencia de Aminoácidos , Microscopía de Túnel de RastreoRESUMEN
Carbonated water is a fundamental part of many drinks and its effects have been studied in many pathological situations. However, cells and tissue damage as a consequence of carbonated water has not been the subject of extensive research. We assessed the short-term effects of soda on in vitro Hanging-drop culture of myoblasts and ex vivo lower limb of 8-day-old chicken embryo skeletal muscle tissue. Several groups weren designed: a) Control (Con-tyr), b) Carbonated water (Car), c) Coffe (Caf), and d) Cola beverage (Glu). The samples were observed with light microscopy and digital imaging analysis was performed. The ultra-structure of control and treated tissue were observed with electron microscopy. Immunohistochemistry techniques, such as terminal deoxynucleotidyl transferase-mediated dUTP nick- end labeling (TUNEL), TACTS Blue Label (TdT Kits) of R&D Systems were used. The myoblasts monolayers treated with soda showed plenty of eosinophilics elements. The eosinophily corresponds to higher percentage of cell death. The muscular tissue of the low limb treated with carbonated water (Car) showed calcium phosphate and collagen decreases, 53,86% and 82,95% respectively and enlarged nuclei of a higher size, with an evident loss of the parallel arrangement and fragmented nuclei. Compared to control samples, the muscular disorganization was accompanied by a positive reaction of the apoptotic bodies on TACS, also a positive reaction to ApopTacg and another positive reaction for the metalloproteases in the inter fibrillar cartilage matrix. These changes were not significant in Tyrode's solution controls, Coffee and Cola beverage groups. The morphological outcome can be apoptosis, necrosis or a mixed phenotype, suggesting that the carbonated water toxic effect might be related to these cell death processes. Further research, exploring biochemical factors will be required to elucidate necro-apoptotic cell death induced by carbonated water.
El agua carbonatada constituye una parte fundamental en muchas bebidas y su efecto ha sido estudiado en muchas situaciones patológicas. Sin embargo, el daño celular y de tejido como consecuencia del agua carbonatada no ha sido claramente investigado. El presente trabajo evalúa el efecto agudo in vitro de la soda sobre mioblastos obtenidos por cultivos en gota pendiente y el efecto sobre tejido muscular esquelético in vivo del miembro inferior de pollo de 8 días de desarrollo. Cuatro grupos de embriones fueron seleccionados al azar: a) Control (Con-tyr), b) Agua Carbonatada o Soda Club (Car), c) Café (Caf) y d) Bebida de cola (Glu). Las muestras fueron observadas por microscopía de luz. El análisis de imágenes digitales fue realizado. La ultraestructura del tejido control y tratado fue observada con Microscopía Electrónica de Transmisión (MET). La determinación de apoptosis fue realizada a través de TUNEL y l TACS Blue Label. La actividad de metaloproteasa MMP-1 fue ensayada. La población de mioblastos tratados con Soda Club mostró un elevado número de elementos eosinofílicos interpretado como un elevado número de células muertas, a diferencia del control y el grupo tratado con cafeína y bebida de Cola. En el tejido muscular se determinó una reducción de fosfatos de calcio y fibras de colágeno en una proporción de 53,86% y 82,95% respectivamente, acompañada por un desarreglo de las fibras y núcleos fragmentados, con reacción positiva para cuerpos apoptóticos y metaloproteasas en la matriz interfibrilar. Los resultados sugieren que el efecto tóxico del agua carbonatada sobre células y tejido pudiera estar vinculado con procesos combinados de muerte celular como necro-apoptosis. Se sugiere una mayor exploración de los eventos moleculares para dilucidar la combinación de los procesos de muerte celular sugerida en el presente trabajo.
Asunto(s)
Animales , Femenino , Embrión de Pollo , Apoptosis , Embrión de Pollo/anatomía & histología , Embrión de Pollo , Embrión de Pollo/ultraestructura , Extremidad Inferior/anatomía & histología , Extremidad Inferior/fisiopatología , Bebidas Gaseosas/efectos adversos , Bebidas Gaseosas/toxicidad , Microscopía Electrónica de Transmisión/métodos , Microscopía Electrónica de Transmisión/veterinaria , Microscopía de Túnel de Rastreo/métodos , Microscopía de Túnel de Rastreo/veterinaria , Muerte Celular , Muslo/anatomía & histología , MusloRESUMEN
The general aim of this paper was to characterize some changes induced by androgen receptors blockage in the epithelial cells of the mouse epididymis. The antiandrogen flutamide was injected (10 mg/Kg b.w.) to adult male mice which were sacrificed 24h. and 72h. after. Controls injected with the vehicle (corn oil) were sacrificed at the same intervals. Cryosections were made of the epididymides and examined by the TUNEL method for quantification of apoptosis and also using immunocytochemistry to visualize the expression of the stress protein HSP70. The highest indexes of apoptosis were observed in the caput epididymis after 72 h. and were of 7.40 cells/1000 in contrast to controls (0.21 cells/1000). HSP70 appeared particularly increased in the caput and cauda epididymis after 72 h. treatment. Results indicated that the blockage of androgen receptors induces apoptosis and a HSP70 expression in the principal epithelial cells of the mouse epididymis, and that these changes occur in a region-specific fashion.
Este trabajo estudia los cambios inducidos por el bloqueador de receptores de andrógeno flutamida en el epitelio del epidídimo del ratón. Varios machos adultos fueron inyectados con flutamida (1Omg/Kg.b.w.) y se sacrificaron a las 24 y 72horas. Otros machos, que sirvieron de controles fueron inyectados sólo con el vehículo empleado para las inyecciones (aceite de maíz) y se sacrificaron a intervalos similares. Los epidídimos tratados y controles fueron examinados mediante el método TÚNEL para cuantificar la apoptosis y mediante procedimientos inmunocitoquímicos para localizar la proteína de stress HSP70. El índice apoptótico más alto fue observado en la cabeza del epidídimo después de 72 horas de tratamiento. HSP70 se observó también a las 72 horas en la cabeza y en la cauda epididimaria. Los resultados indican que el bloqueo de los receptores de andrógenos induce apoptosis y expresión de HSP70 en las células principales del epitelio epididimario, y que estos cambios ocurren afectando a regiones específicas del epidídimo.
Asunto(s)
Masculino , Adulto , Animales , Ratones , Antagonistas de Andrógenos , Epidídimo/anatomía & histología , Epidídimo/crecimiento & desarrollo , Epidídimo , Flutamida/administración & dosificación , Flutamida/toxicidad , Apoptosis , Células Epiteliales , Homeostasis , Microscopía de Túnel de Rastreo/métodos , /efectos adversos , /metabolismoRESUMEN
Conformations of surface atoms in various stages of nanogold-based genechip testing were scanned by the atomic force microscope based on the scanning tunneling microscope. The findings were: First, the surface atoms of genechip slide (formylphenyl glass) were in a regular porous-arrangement; Second, after combination with probe, the regular porous arrangement changed to be irregular; Third, after hybridization with the target nucleic acid, the surface atoms were once again in a cable-like arrangement which was relatively structured and intensively cross-parallel. However, after the silver staining, the surface atoms showed a larger block structure with serious unevenness. From these results we can intuitively know the process and differences in probe combination, nucleic acid hybridization, and silver staining. Moreover, the relevant experiment was verified at the micro-level.
Asunto(s)
Oro , Nanopartículas del Metal , Química , Microscopía de Fuerza Atómica , Métodos , Microscopía de Túnel de Rastreo , Métodos , Conformación Molecular , Nanotecnología , Métodos , Análisis de Secuencia por Matrices de Oligonucleótidos , Métodos , Tamaño de la Partícula , Propiedades de SuperficieRESUMEN
Entre todos los tumores, el carcinoma tiroideo (CT) es poco frecuente, se caracteriza por su lenta evolución y elevado porcentaje de curación. Nuestro objetivo es estudiar las características de los pacientes con CT. Analizamos retrospectivamente a 171 pacientes, edad media al diagnóstico 41.1( ± 14.6 años), que consultaron entre los años 2000-04 por CT. Se evaluaron datos de anamnesis, métodos de diagnóstico, anatomía patológica y evolución. Agrupamos a los tumores por el tamaño y según TNM (tumor-adenopatía-metástasis) en estadios (E). La presencia de tiroglobulina estimulada (Tg) > 2 ng/ml e imagen positiva (con 131I u otro radiotrazador) fueron consideradas como positivas para CT residual. De la población total el 88% fue sexo femenino, el 62% menores de 45 años, y el 77.1% tuvo función tiroidea normal. La punción con aguja fina (PAAF) fue diagnóstica en 78%. El 96% fue carcinoma papilar (CTP), 63% presentaban E I; 14% E II; 19% E III y 4% E IV. Se detectó CT residual en el 90% de los pacientes con Tg entre 2 y 10, y en el 100% con Tg > 10 ng/ml, mientras que con Tg < 2 el 18% mostró imagen positiva. No encontramos correlación significativa con antecedentes patológicos ni con ningún signo relevante en imágenes. En conclusión, en nuestra población el CTP fue predominante. Más frecuente en mujeres, en menores de 45 años y en eutiroideos. El nivel de Tg estimulada es un buen indicador de CT residual, pero no es una prueba suficiente para seleccionar pacientes libres de enfermedad
The thyroid carcinoma (TC) is not very frequent among all cancers. Its course is slow and is high potentially curable. Our aim was to analyse the characteristics in patients with TC. A retrospective analysis on 171 patients, with an average age of 41.1 (±14,6), who asked for TC to our service between the years 2000-04, was performed. From case histories it was evaluated: anamnesis, diagnostic image, histopathology and evolution. Tumours were grouped for size and TNM (tumour-nodule-metastasis) in stages (S). A stimulated serum thyroglobulin level > 2 ng/ml and positive image with 131I or another nuclear marker were considered as positive for residual TC. In the totality of the analyzed patients 88% were female, 62% below 45 years old, and in 77% the thyroid function was normal. The fine needle aspiration (FNA) was diagnostic in 78%. Papillary thyroid carcinoma (PTC) in 96%. The 63% was SI; 14% SII; 19% SIII and 4% SIV. During follow-up, we observed that 90% of patients with Tg between 2 and 10 had evidence of residual TC, and 100% with Tg > 10 ng/ml, whereas 18% of those whose stimulated Tg < 2 presented positive image. There was not found significative correlation with pathologic antecedents or relevant image signs. In conclusion: TCP was the most frequent carcinoma in women, in patients younger than 45 years and in those who have euthyroid function. A stimulated serum thyroglobulin level was a good indicator for residual TC, but failed to select those patients who were disease free
Asunto(s)
Humanos , Masculino , Femenino , Adulto , Persona de Mediana Edad , Carcinoma Papilar/patología , Neoplasias de la Tiroides/patología , Biopsia con Aguja Fina , Carcinoma Papilar/sangre , Bocio Nodular/sangre , Bocio Nodular/patología , Espectroscopía de Resonancia Magnética , Microscopía de Túnel de Rastreo , Metástasis de la Neoplasia , Estadificación de Neoplasias , Neoplasia Residual , Pronóstico , Estudios Retrospectivos , Factores Sexuales , Tomógrafos Computarizados por Rayos X , Tiroglobulina/sangre , Neoplasias de la Tiroides/sangre , Nódulo Tiroideo/sangre , Nódulo Tiroideo/patología , Tirotropina/sangre , Biomarcadores de Tumor/sangreRESUMEN
Entre todos los tumores, el carcinoma tiroideo (CT) es poco frecuente, se caracteriza por su lenta evolución y elevado porcentaje de curación. Nuestro objetivo es estudiar las características de los pacientes con CT. Analizamos retrospectivamente a 171 pacientes, edad media al diagnóstico 41.1( ± 14.6 años), que consultaron entre los años 2000-04 por CT. Se evaluaron datos de anamnesis, métodos de diagnóstico, anatomía patológica y evolución. Agrupamos a los tumores por el tamaño y según TNM (tumor-adenopatía-metástasis) en estadios (E). La presencia de tiroglobulina estimulada (Tg) > 2 ng/ml e imagen positiva (con 131I u otro radiotrazador) fueron consideradas como positivas para CT residual. De la población total el 88% fue sexo femenino, el 62% menores de 45 años, y el 77.1% tuvo función tiroidea normal. La punción con aguja fina (PAAF) fue diagnóstica en 78%. El 96% fue carcinoma papilar (CTP), 63% presentaban E I; 14% E II; 19% E III y 4% E IV. Se detectó CT residual en el 90% de los pacientes con Tg entre 2 y 10, y en el 100% con Tg > 10 ng/ml, mientras que con Tg < 2 el 18% mostró imagen positiva. No encontramos correlación significativa con antecedentes patológicos ni con ningún signo relevante en imágenes. En conclusión, en nuestra población el CTP fue predominante. Más frecuente en mujeres, en menores de 45 años y en eutiroideos. El nivel de Tg estimulada es un buen indicador de CT residual, pero no es una prueba suficiente para seleccionar pacientes libres de enfermedad (AU)
The thyroid carcinoma (TC) is not very frequent among all cancers. Its course is slow and is high potentially curable. Our aim was to analyse the characteristics in patients with TC. A retrospective analysis on 171 patients, with an average age of 41.1 (±14,6), who asked for TC to our service between the years 2000-04, was performed. From case histories it was evaluated: anamnesis, diagnostic image, histopathology and evolution. Tumours were grouped for size and TNM (tumour-nodule-metastasis) in stages (S). A stimulated serum thyroglobulin level > 2 ng/ml and positive image with 131I or another nuclear marker were considered as positive for residual TC. In the totality of the analyzed patients 88% were female, 62% below 45 years old, and in 77% the thyroid function was normal. The fine needle aspiration (FNA) was diagnostic in 78%. Papillary thyroid carcinoma (PTC) in 96%. The 63% was SI; 14% SII; 19% SIII and 4% SIV. During follow-up, we observed that 90% of patients with Tg between 2 and 10 had evidence of residual TC, and 100% with Tg > 10 ng/ml, whereas 18% of those whose stimulated Tg < 2 presented positive image. There was not found significative correlation with pathologic antecedents or relevant image signs. In conclusion: TCP was the most frequent carcinoma in women, in patients younger than 45 years and in those who have euthyroid function. A stimulated serum thyroglobulin level was a good indicator for residual TC, but failed to select those patients who were disease free (AU)
Asunto(s)
Humanos , Masculino , Femenino , Adulto , Persona de Mediana Edad , Neoplasias de la Tiroides/patología , Carcinoma Papilar/patología , Neoplasias de la Tiroides/sangre , Carcinoma Papilar/sangre , Nódulo Tiroideo/sangre , Nódulo Tiroideo/patología , Bocio Nodular/sangre , Bocio Nodular/patología , Tirotropina/sangre , Tiroglobulina/sangre , Biomarcadores de Tumor/sangre , Neoplasia Residual , Estadificación de Neoplasias , Metástasis de la Neoplasia , Pronóstico , Biopsia con Aguja Fina , Microscopía de Túnel de Rastreo , Estudios Retrospectivos , Factores Sexuales , Tomógrafos Computarizados por Rayos X , Espectroscopía de Resonancia MagnéticaRESUMEN
Entre todos los tumores, el carcinoma tiroideo (CT) es poco frecuente, se caracteriza por su lenta evolución y elevado porcentaje de curación. Nuestro objetivo es estudiar las características de los pacientes con CT. Analizamos retrospectivamente a 171 pacientes, edad media al diagnóstico 41.1( ± 14.6 años), que consultaron entre los años 2000-04 por CT. Se evaluaron datos de anamnesis, métodos de diagnóstico, anatomía patológica y evolución. Agrupamos a los tumores por el tamaño y según TNM (tumor-adenopatía-metástasis) en estadios (E). La presencia de tiroglobulina estimulada (Tg) > 2 ng/ml e imagen positiva (con 131I u otro radiotrazador) fueron consideradas como positivas para CT residual. De la población total el 88% fue sexo femenino, el 62% menores de 45 años, y el 77.1% tuvo función tiroidea normal. La punción con aguja fina (PAAF) fue diagnóstica en 78%. El 96% fue carcinoma papilar (CTP), 63% presentaban E I; 14% E II; 19% E III y 4% E IV. Se detectó CT residual en el 90% de los pacientes con Tg entre 2 y 10, y en el 100% con Tg > 10 ng/ml, mientras que con Tg < 2 el 18% mostró imagen positiva. No encontramos correlación significativa con antecedentes patológicos ni con ningún signo relevante en imágenes. En conclusión, en nuestra población el CTP fue predominante. Más frecuente en mujeres, en menores de 45 años y en eutiroideos. El nivel de Tg estimulada es un buen indicador de CT residual, pero no es una prueba suficiente para seleccionar pacientes libres de enfermedad (AU)
The thyroid carcinoma (TC) is not very frequent among all cancers. Its course is slow and is high potentially curable. Our aim was to analyse the characteristics in patients with TC. A retrospective analysis on 171 patients, with an average age of 41.1 (±14,6), who asked for TC to our service between the years 2000-04, was performed. From case histories it was evaluated: anamnesis, diagnostic image, histopathology and evolution. Tumours were grouped for size and TNM (tumour-nodule-metastasis) in stages (S). A stimulated serum thyroglobulin level > 2 ng/ml and positive image with 131I or another nuclear marker were considered as positive for residual TC. In the totality of the analyzed patients 88% were female, 62% below 45 years old, and in 77% the thyroid function was normal. The fine needle aspiration (FNA) was diagnostic in 78%. Papillary thyroid carcinoma (PTC) in 96%. The 63% was SI; 14% SII; 19% SIII and 4% SIV. During follow-up, we observed that 90% of patients with Tg between 2 and 10 had evidence of residual TC, and 100% with Tg > 10 ng/ml, whereas 18% of those whose stimulated Tg < 2 presented positive image. There was not found significative correlation with pathologic antecedents or relevant image signs. In conclusion: TCP was the most frequent carcinoma in women, in patients younger than 45 years and in those who have euthyroid function. A stimulated serum thyroglobulin level was a good indicator for residual TC, but failed to select those patients who were disease free (AU)
Asunto(s)
Humanos , Masculino , Femenino , Adulto , Persona de Mediana Edad , Neoplasias de la Tiroides/patología , Carcinoma Papilar/patología , Neoplasias de la Tiroides/sangre , Carcinoma Papilar/sangre , Nódulo Tiroideo/sangre , Nódulo Tiroideo/patología , Bocio Nodular/sangre , Bocio Nodular/patología , Tirotropina/sangre , Tiroglobulina/sangre , Biomarcadores de Tumor/sangre , Neoplasia Residual , Estadificación de Neoplasias , Metástasis de la Neoplasia , Pronóstico , Biopsia con Aguja Fina , Microscopía de Túnel de Rastreo , Estudios Retrospectivos , Factores Sexuales , Tomógrafos Computarizados por Rayos X , Espectroscopía de Resonancia MagnéticaRESUMEN
Objective Some patients with obstructing carcinoma of the prostate may fail to resume spontaneous voiding following bilateral orchidectomy. This group of patients would require an additional procedure in the form of limited transurethral resection of the prostate gland (tunneling TURP) to be able to resume spontaneous voiding. The objective of this study was to compare performing simultaneous tunneling TURP and bilateral orchidectomy on one hand with deferring channel TURP for at least one month after bilateral orchidectomy in cases where the patient has failed to resume spontaneous voiding on the other. Patients and Methods Forty-seven patients with obstructing carcinoma of the prostate were studied. Group I consisted of 22 patients who had simultaneous bilateral orchidectomy and tunneling TURP of the prostate; while Group II consisted of 25 patients who had tunneling TURP at least one month after bilateral orchidectomy. The groups were compared with regard to the ease of operation and postoperative management. Results Intra-operative bleeding; the need for repeated cleaning of the resection loop; the operating time and the hospital stay were significantly less in Group-II patients compared to Group I. Conclusion The results suggest that tunneling TURP when performed at least one month after bilateral orchidectomy allows enough time for a significant reduction of tissue friability; tissue adhesion to the resection loop; tumor circulation; intra-operative bleeding; operating time and postoperative hospital stay