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3.
Inorg Chem ; 62(10): 4291-4303, 2023 Mar 13.
Artículo en Inglés | MEDLINE | ID: mdl-36862825

RESUMEN

In this work, we focus on understanding the morphology and photocatalytic properties of CeO2 nanocrystals (NCs) synthesized via a microwave-assisted solvothermal method using acetone and ethanol as solvents. Wulff constructions reveal a complete map of available morphologies and a theoretical-experimental match with octahedral nanoparticles obtained through synthesis using ethanol as solvent. NCs synthesized in acetone show a greater contribution of emission peaks in the blue region (∼450 nm), which may be associated with higher Ce3+ concentration, originating shallow-level defects within the CeO2 lattice while for the samples synthesized in ethanol a strong orange-red emission (∼595 nm) suggests that oxygen vacancies may originate from deep-level defects within the optical bandgap region. The superior photocatalytic response of CeO2 synthesized in acetone compared to that of CeO2 synthesized in ethanol may be associated with an increase in long-/short-range disorder within the CeO2 structure, causing the Egap value to decrease, facilitating light absorption. Furthermore, surface (100) stabilization in samples synthesized in ethanol may be related to low photocatalytic activity. Photocatalytic degradation was facilitated by the generation of ·OH and ·O2- radicals as corroborated by the trapping experiment. The mechanism of enhanced photocatalytic activity has been proposed suggesting that samples synthesized in acetone tend to have lower e'─h· pair recombination, which is reflected in their higher photocatalytic response.

4.
Chem Biodivers ; 20(1): e202200631, 2023 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-36423339

RESUMEN

This study aimed to determine the phenolic compounds profile, antioxidant potential and cytotoxicity of extracts and fractions of Caesalpinia palmeri. Methanolic extracts were generated from C. palmeri berries, stems and flowers. The latter was subjected to liquid-liquid partition, obtaining hexane, ethyl acetate and residues fractions. Results showed that the flower extract and ethyl acetate fraction had a larger concentration of phenolic compounds (148.9 and 307.9 mg GAE/g, respectively), being ellagic acid (6233.57 and 19550.08 µg/g, respectively), quercetin-3-ß-glycoside (3023.85 and 8952.55 µg/g, respectively) and gallic acid (2212.98 and 8422.34 µg/g, respectively) the most abundant compounds. Flower extract and ethyl acetate fraction also presented the highest antioxidant capacity on all tested methods (DPPH, ABTS, ORAC and FRAP) and low cytotoxicity against ARPE-19 cells (IC50 >170 µg/mL). C. palmeri possessed high antioxidant potential, associated with the presence of phenolic compounds and low cytotoxicity, suggesting that they could represent an option to counter oxidative stress.


Asunto(s)
Antioxidantes , Caesalpinia , Antioxidantes/farmacología , Antioxidantes/química , Extractos Vegetales/farmacología , Extractos Vegetales/química , Acetatos
5.
Appl Opt ; 60(19): 5623-5628, 2021 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-34263854

RESUMEN

A digital holographic interferometer using a collimated beam in transmission mode to illuminate a flow coming from a diffusion flame is presented. The optical system proposes an indirect visualization of the flow to avoid saturation at the sensor. It can detect the intensity signal as a classical schlieren technique and the phase changes due to the presence of the flow. It is possible to retrieve a pseudo-3D flow's view and different gradient maps using the optical phase. According to the knife edge's position, these gradients could be observed in classical schlieren one at a time, but the proposed system could retrieve them all with a single image hologram. As proof of principle, a flame's flow is simultaneously observed with the optical system and a Z-type schlieren set up. A comparison of the visualized flows at different stages of the flame is presented and discussed. A temperature profile is obtained and validated with a thermocouple's point thermal measurements taking the resulting optical phase. Results from both optical techniques show a good agreement.

6.
Phys Rev Lett ; 126(1): 012002, 2021 Jan 08.
Artículo en Inglés | MEDLINE | ID: mdl-33480779

RESUMEN

We report the first measurement of coherent elastic neutrino-nucleus scattering (CEvNS) on argon using a liquid argon detector at the Oak Ridge National Laboratory Spallation Neutron Source. Two independent analyses prefer CEvNS over the background-only null hypothesis with greater than 3σ significance. The measured cross section, averaged over the incident neutrino flux, is (2.2±0.7)×10^{-39} cm^{2}-consistent with the standard model prediction. The neutron-number dependence of this result, together with that from our previous measurement on CsI, confirms the existence of the CEvNS process and provides improved constraints on nonstandard neutrino interactions.

7.
Rev. cir. (Impr.) ; 72(1): 72-75, feb. 2020. ilus
Artículo en Español | LILACS | ID: biblio-1092894

RESUMEN

Resumen Introducción Los leiomiosarcomas de la vena cava inferior son tumores raros, sólo hay 300 casos descritos en la literatura. Su incidencia es mayor en mujeres, suelen aparecer entre los 50-60 años, y presentan una progresión lenta y mal pronóstico. Los síntomas son inespecíficos haciendo que el diagnóstico se realice de forma tardía, éste se realiza mediante pruebas de imagen y biopsia guiada. Caso clínico Se presenta el caso de un varón de 73 años con diagnóstico de leiomiosarcoma de la vena cava inferior, como hallazgo incidental en TC de control, tratado mediante radioterapia neoadyuvante, cirugía y radioterapia intraoperatoria. Discusión El único tratamiento que ha descrito modificaciones en la supervivencia es la cirugía. El papel de la adyuvancia y neoadyuvancia en estos tumores es muy controvertido. La elección de la actitud terapéutica dependerá de la localización del tumor, tamaño, la relación con estructuras adyacentes y la presencia de circulación colateral.


Introduction Leiomyosarcomas of the inferior vena cava are rare tumors, with fewer than 300 cases reported. Its incidence is higher in females, usually appear in the sixth decade and they have a slow-growing and poor prognosis. Symptoms are generally non-specific. Diagnosis is made with imaging studies and guided biopsy. Clinical Case We report a case of a 73-year-old male patient with leimyosarcoma of the inferior vena cava treated by neoadjuvant radiotherapy, surgery and intraoperative radiotherapy. Discussion Surgery is the only treatment that can improve the survival. The role of the adjuvancy and neoadjuvancy is very controversial. Surgical management is determined by the location of the tumour, the relationship with adjacent structures and the presence of collateral veins.


Asunto(s)
Humanos , Masculino , Anciano , Vena Cava Inferior/patología , Neoplasias Vasculares/cirugía , Neoplasias Vasculares/diagnóstico por imagen , Leiomiosarcoma/cirugía , Leiomiosarcoma/diagnóstico por imagen , Grupo de Atención al Paciente , Periodo Posoperatorio , Vena Cava Inferior/cirugía , Tomografía Computarizada por Rayos X , Resultado del Tratamiento , Radioterapia Adyuvante/métodos , Hallazgos Incidentales , Leiomiosarcoma/radioterapia
8.
Rev. biol. trop ; 68(4)2020.
Artículo en Español | LILACS-Express | LILACS | ID: biblio-1507726

RESUMEN

Introducción: La vainilla (Vanilla planifolia Andrews) es una planta CAM de gran importancia económica en el mercado mundial de saborizantes y aromatizantes. Por ser una planta hemiepífita que inicialmente crece en el sotobosque sombreado y posteriormente asciende hasta el dosel, se aclimata a diferentes condiciones de radiación y humedad. La posibilidad de extender su cultivo a zonas secas donde sea menor la incidencia de enfermedades, dependerá de su respuesta a períodos prolongados de sequía. Objetivo: Evaluar los efectos de la interacción entre la radiación y la humedad sobre los parámetros de la fotosíntesis y funcionamiento del CAM de plantas de vainilla en sus fases iniciales de desarrollo vegetativo, y determinar si las condiciones de radiación en las que crece la planta pueden ayudar a moderar los efectos negativos de la sequía. Métodos: Se evaluaron plantas de vainilla que crecieron con riego durante 18 meses en casetas con iluminación relativa (IR) de 8, 17, 31 y 67 %; posteriormente se suspendió el riego y se fueron deshidratando durante 94 días hasta alcanzar un contenido de humedad crítico (contenido hídrico relativo, CHR ≤ 50 %), y finalmente se reinició el riego durante 22 días; se evaluó el efecto de estos procesos sobre la asimilación de CO2, la acidez titulable y la eficiencia cuántica del Fotosistema II (Fv/Fm). Resultados: Bajo condiciones intermedias de IR (17 % y 31 %), la asimilación de CO2 y laacumulación nocturna de ácidos orgánicos presentaron la menor afectación por el déficit hídrico, así como la mejor recuperación luego de la rehidratación. El CHR se vio más afectado por la disponibilidad de agua en el tejido vegetal, mientras que Fv/Fm lo fue por el ambiente de radiación. Los efectos combinados de estrés hídrico y alta radiación ocasionaron daños irreversibles en la fotosíntesis para el tratamiento de IR de 67 %. Conclusiones: En las plantas de vainilla, el impacto negativo de la sequía sobre los parámetros de la fotosíntesis fue mayor en alta radiación; sin embargo, en condiciones de baja radiación también aumentó la susceptibilidad de las plantas a la sequía, en comparación con los ambientes de radiación intermedia, en los cuales la densidad de flujo de fotones media fue de 340 μmol m-2 seg-1 (17 % de IR) y 620 μmol m-2 seg-1 (31 % de IR). Estos resultados sugieren el potencial de cultivar vainilla en zonas con sequía estacional bajo sistemas productivos de baja tecnificación, manteniendo estas condiciones de radiación.


Introduction: Vanilla planifolia Andrews is a CAM plant of economic importance in the global market of flavorings and essences. Being a hemiepiphyte which initially grows in the shady understory and later climbs to the canopy, it acclimates to different conditions of radiation and humidity. The possibility of extending this crop to dry areas where the incidence of diseases is lower will depend on the response to prolonged periods of drought. Objective: To evaluate the effects of the interaction of radiation and humidity on the parameters of photosynthesis and operation of CAM of vanilla plants, and to determine if the radiation environment could help to moderate the negative effects of drought. Methods: We evaluated well-watered vanilla plants grown for 18 months in relative illumination (RI) of 8, 17, 31 and 67 %, which underwent dehydration for 94 days until reaching critical water content (relative water content, RWC < 50 %) and then rehydration for 22 days; variables evaluated were: CO2 assimilation, titratable acidity, and quantum efficiency of Photosystem II (Fv / Fm). Results: Under intermediate conditions of radiation (17 % and 31 % RI), CO2 assimilation and nocturnal accumulation of organic acids were less affected by water deficit and also showed the best recovery after rehydration. The RWC was most affected by the water available in plant tissue, while Fv / Fm was affected by radiation. The combined effects of water stress and high radiation caused irreversible damage to photosynthesis for the 67 % RI treatment. Conclusions: In vanilla plants, the negative impact of drought on photosynthetic parameters was greater in high radiation; however, in low radiation conditions the susceptibility of plants to drought also increased, as compared to intermediate radiation environments, which were under a mean photon flux density of 340 µmol m-2 s-1 (17 % IR) and 620 µmol m-2 s-1 (31 % IR). These results suggest the potential for growing vanilla in areas with seasonal drought under low-tech production systems, maintaining these radiation conditions.

9.
BMC Genomics ; 20(1): 452, 2019 Jun 03.
Artículo en Inglés | MEDLINE | ID: mdl-31159741

RESUMEN

BACKGROUND: Full RNA-Seq is a fundamental research tool for whole transcriptome analysis. However, it is too costly and time consuming to be used in routine clinical practice. We evaluated the transcript quantification agreement between RNA-Seq and a digital multiplexed gene expression platform, and the subtype call after running the PAM50 assay in a series of breast cancer patients classified as triple negative by IHC/FISH. The goal of this study is to analyze the concordance between both expression platforms overall, and for calling PAM50 triple negative breast cancer intrinsic subtypes in particular. RESULTS: The analyses were performed in paraffin-embedded tissues from 96 patients recruited in a multicenter, prospective, non-randomized neoadjuvant triple negative breast cancer trial (NCT01560663). Pre-treatment core biopsies were obtained following clinical practice guidelines and conserved as FFPE for further RNA extraction. PAM50 was performed on both digital multiplexed gene expression and RNA-Seq platforms. Subtype assignment was based on the nearest centroid classification following this procedure for both platforms and it was concordant on 96% of the cases (N = 96). In four cases, digital multiplexed gene expression analysis and RNA-Seq were discordant. The Spearman correlation to each of the centroids and the risk of recurrence were above 0.89 in both platforms while the agreement on Proliferation Score reached up to 0.97. In addition, 82% of the individual PAM50 genes showed a correlation coefficient > 0.80. CONCLUSIONS: In our analysis, the subtype calling in most of the samples was concordant in both platforms and the potential discordances had reduced clinical implications in terms of prognosis. If speed and cost are the main driving forces then the preferred technique is the digital multiplexed platform, while if whole genome patterns and subtype are the driving forces, then RNA-Seq is the preferred method.


Asunto(s)
Biomarcadores de Tumor/genética , Perfilación de la Expresión Génica/métodos , Secuenciación de Nucleótidos de Alto Rendimiento/métodos , Recurrencia Local de Neoplasia/genética , Neoplasias de la Mama Triple Negativas/genética , Femenino , Estudios de Seguimiento , Regulación Neoplásica de la Expresión Génica , Humanos , Masculino , Recurrencia Local de Neoplasia/patología , Pronóstico , Estudios Prospectivos , Neoplasias de la Mama Triple Negativas/patología
11.
J Food Sci Technol ; 55(11): 4477-4484, 2018 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-30333644

RESUMEN

The progressive elimination of fish discards established by the European Union Council in 2013 has stimulated the valorization of flesh from discarded high-quality species with good protein functional properties but which frequently have excessive fish-bones, fat, strange flavours, soft texture, etc. The present study therefore focuses on valorization of the extracted muscle (minced muscle), from several fish species frequently discarded in north-western Spanish fisheries (Atlantic Ocean): Blue whiting (Micromesistius poutassou), Mackerel (Scomber scombrus), Red scorpionfish (Scorpaena scrofa), Pouting (Trisoreptus luscus) and Gurnard (Trigla spp.). Valorization of these discarded fish resources is a key objective for the survival of the fishery sector in this area. In this regard present study was planned to examine the behaviour of the mince during 6 months of frozen storage by means of physicochemical and sensory analyses, and to test consumer acceptance of three technologically different products (burgers, nuggets and structured fingers) prepared with fish mince from different species. Results indicated that protein aggregation started at the outset of frozen storage but progressed very slowly, with the exception of non-washed blue whiting and red scorpionfish minces. Moreover, during frozen storage lipid oxidation increased in all samples; the increase was with two objectives highest in minced mackerel, a fatty fish, but no rancid flavour was detected. All mince samples presented acceptable physicochemical properties and good sensory acceptability after 6 months of frozen storage. Acceptability of final products made with these minces was high in all cases. Burgers were more acceptable for consumers aged over 40 and fingers and nuggets more for younger people.

12.
Curr Hypertens Rep ; 20(3): 26, 2018 03 27.
Artículo en Inglés | MEDLINE | ID: mdl-29589184

RESUMEN

PURPOSE OF REVIEW: Resistant hypertension (RHTN) is a condition in which besides the antihypertensive therapy using at least three different drugs (including a diuretics), brachial blood pressure does not reach the target (e.g., 140/90 mmHg). RECENT FINDINGS: Despite the diversity of clinical presentations, we divide RHTN in two major groups according to blood pressure and number of drugs taken: controlled (C-RHTN) and uncontrolled (UC-RHTN) resistant hypertension, with refractory hypertension (RfHTN) included in the latter subgroup. Both C-RHTN and UC-RHTN are heterogenic and complex syndromes. To better approach this matter, the some pathophysiological mechanisms (increased volemia, hyperactivity, plasma cortisol, adipocitokines, and other pro-inflammatory factors), have a pivotal clinical role. Some features (African ethnic, obesity, age > 60, LV hypertrophy, and vascular stiffness) increase the risk of refractoriness as well as worst prognosis. Based on increased target organ damage, cardiovascular risk and events will be addressed in this review. Our conclusion is that although both C-RHTN and UC-RHTN are extreme phenotypes of hard-to-control BP, some mechanisms of the disease and clinical expressions are distinct. According to these differences, "UC-RHTN and C-RHTN are not in the same bag."


Asunto(s)
Hipertensión/fisiopatología , Antihipertensivos/uso terapéutico , Presión Sanguínea/efectos de los fármacos , Humanos , Hipertensión/diagnóstico , Hipertensión/tratamiento farmacológico
13.
J Helminthol ; 92(6): 765-768, 2018 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-29103381

RESUMEN

Gnathostoma turgidum is a nematode parasite that exploits the stomach of Virginian opossums, Didelphis virginiana, in Latin America. The opossum is the definitive host of G. turgidum in the wild. Intrahepatic growth and maturation of the parasite, subsequent migration to the stomach and spontaneous expulsion are common. However, the histopathological lesions caused by G. turgidum are poorly described. A better understanding of the life cycle of this parasite and the pathological changes in natural host-parasite interactions could help to clarify the progression of human infections caused by Gnathostoma binucleatum. The aim of this work was to study morphological changes in the liver and stomach of D. virginiana during natural infection and adult worm expulsion. Three opossums naturally infected with G. turgidum were captured from an endemic area of gnathostomosis. Three uninfected opossums captured from a non-endemic area were used as controls. The opossums were sacrificed at different stages of infection (March, May and December), and a histopathological study of their livers and stomachs was conducted. Injuries in livers were observed by histopathology - areas of necrosis and collagen septa were identified. Parasites caused nodules with necrosis on the periphery of lesions, and collagen fibres were also observed in stomachs. Collagen septa may be caused by antigenic remains of the parasite. Further immunological studies are necessary to verify that stimulation is caused by these factors.


Asunto(s)
Didelphis/parasitología , Gnathostoma/aislamiento & purificación , Gnathostomiasis/veterinaria , Hígado/patología , Estómago/patología , Animales , Gnathostomiasis/parasitología , Gnathostomiasis/patología , Histocitoquímica , América Latina , Hígado/parasitología , Estómago/parasitología
14.
Food Res Int ; 102: 639-646, 2017 12.
Artículo en Inglés | MEDLINE | ID: mdl-29195995

RESUMEN

The aim of this study was to evaluate technological and antioxidant properties, including in vitro bioaccessibility of polyphenols, conferred on raw anchovy mince by the addition of polyphenol-rich grape pomace dietary fibre at different concentrations. For this purpose, headed and gutted anchovy was heat-flayed, deboned and mixed with 0%, 2%, 3%, 4% grape pomace dietary fibre. A significant increase (P<0.05) in the concentration of polyphenols and associated antioxidant capacity was detected when grape pomace dietary fibre was incorporated in a proportion of at least 2% of the final mixture. In vitro digestion showed that the higher the grape pomace dietary fibre content, the higher was the proportion of polyphenols reaching the large intestine. Additionally, it was observed that the ABTS (2,2'-azino-bis(3-ethylbenzo-thiazoline-6-sulfonic acid) assay seems to be more suitable for evaluating antioxidant capacity in this kind of samples than FRAP (Ferric Reducing Antioxidant Power) assay. Technological properties such as mechanical and water holding, as well as sensory scores, indicated excellent qualities and acceptability of all samples. Hence, given the good acceptance of these samples, it should be feasible to make fish products based on mince anchovy as a means of increasing dietary intake of polyphenols with antioxidant capacity, especially considering the high concentration of polyphenols bioaccessible in the large intestine.


Asunto(s)
Fibras de la Dieta/análisis , Productos Pesqueros/análisis , Peces , Polifenoles/química , Polifenoles/farmacocinética , Vitis/química , Animales , Antioxidantes/análisis , Disponibilidad Biológica , Fenómenos Químicos , Comportamiento del Consumidor , Manipulación de Alimentos/métodos , Alimentos Fortificados/análisis , Frutas/química , Humanos , Intestino Grueso/metabolismo , Polifenoles/análisis , Sensación , Resistencia al Corte
15.
Neurobiol Dis ; 108: 261-276, 2017 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-28860088

RESUMEN

The entorhinal cortex (EC) is affected early in Alzheimer's disease, an illness defined by a co-occurrence of tau and amyloid-related pathologies. How the co-occurrence of these pathologies in the EC affects the hippocampal circuit remains unknown. Here we address this question by performing electrophysiological analyses of the EC circuit in mice that express mutant human amyloid precursor protein (hAPP) or tau (hTau), or both in the EC. We show that the alterations in the hippocampal circuit are divergent, with hAPP increasing but hTau decreasing neuronal/circuit excitability. Most importantly, mice co-expressing hAPP and hTau show that hTau has a dominant effect, dampening the excitatory effects of hAPP. Additionally, compensatory synaptic downscaling, in response to increased excitability in EC was observed in subicular neurons of hAPP mice. Based on simulations, we propose that EC interneuron pruning can account for both EC hyperexcitability and subicular synaptic downscaling found in mice expressing hAPP.


Asunto(s)
Precursor de Proteína beta-Amiloide/metabolismo , Corteza Entorrinal/metabolismo , Hipocampo/metabolismo , Neuronas/metabolismo , Proteínas tau/metabolismo , Precursor de Proteína beta-Amiloide/genética , Animales , Simulación por Computador , Corteza Entorrinal/patología , Femenino , Hipocampo/patología , Humanos , Masculino , Potenciales de la Membrana/fisiología , Ratones Endogámicos C57BL , Ratones Transgénicos , Modelos Neurológicos , Mutación , Vías Nerviosas/metabolismo , Vías Nerviosas/patología , Neuronas/patología , Técnicas de Placa-Clamp , Sinapsis/metabolismo , Sinapsis/patología , Transmisión Sináptica/fisiología , Técnicas de Cultivo de Tejidos , Proteínas tau/genética
16.
Science ; 357(6356): 1123-1126, 2017 09 15.
Artículo en Inglés | MEDLINE | ID: mdl-28775215

RESUMEN

The coherent elastic scattering of neutrinos off nuclei has eluded detection for four decades, even though its predicted cross section is by far the largest of all low-energy neutrino couplings. This mode of interaction offers new opportunities to study neutrino properties and leads to a miniaturization of detector size, with potential technological applications. We observed this process at a 6.7σ confidence level, using a low-background, 14.6-kilogram CsI[Na] scintillator exposed to the neutrino emissions from the Spallation Neutron Source at Oak Ridge National Laboratory. Characteristic signatures in energy and time, predicted by the standard model for this process, were observed in high signal-to-background conditions. Improved constraints on nonstandard neutrino interactions with quarks are derived from this initial data set.

17.
Arch Soc Esp Oftalmol ; 92(4): 160-165, 2017 Apr.
Artículo en Inglés, Español | MEDLINE | ID: mdl-28017486

RESUMEN

PURPOSE: To describe the visual outcome and complications associated with phacoemulsification in patients with bilateral retinoblastoma (Rb), with lens opacification secondary to external beam radiotherapy. METHODS: A descriptive study was performed on patients with Rb, treated in Federico Gomez Children's Hospital, Mexico, from January 1997 to August 2015, with external beam radiotherapy eye salvaging. Statistical analysis was performed using Stata 10. RESULTS: A total of 15 patients were included. The mean age at phacoemulsification was 7.5 years. Mean preoperative visual acuity was 1.0LogMAR (range 0.4-1.6), and the mean postoperative visual acuity was 0.7LogMAR (range 0.1-1.6). Twelve patients had visual improvement (P<.05). The visual acuity decreased in one patient with vitreous haemorrhage and secondary glaucoma, and 2 patients with exudative maculopathy secondary to radiation. Mean follow up was 46 months and not a single patient showed tumour re-activation. CONCLUSIONS: Cataract surgery produces a statistically significant improvement in visual acuity. These patients have increased risk for eye complications in the mid- and long-term. It is important to conduct a close follow up due to reactivation of tumour.


Asunto(s)
Extracción de Catarata/efectos adversos , Catarata/etiología , Facoemulsificación/efectos adversos , Complicaciones Posoperatorias/etiología , Traumatismos por Radiación/etiología , Neoplasias de la Retina/radioterapia , Neoplasias de la Retina/cirugía , Retinoblastoma/radioterapia , Retinoblastoma/cirugía , Niño , Preescolar , Femenino , Humanos , Masculino , Resultado del Tratamiento
19.
Philos Trans A Math Phys Eng Sci ; 374(2069)2016 Jun 13.
Artículo en Inglés | MEDLINE | ID: mdl-27140969

RESUMEN

We consider a central system which is coupled via dephasing to an open system, i.e. an intermediate system which in turn is coupled to another environment. Considering the intermediate and far environment as one composite system, the coherences in the central system are given in the form of fidelity amplitudes for a certain perturbed echo dynamics in the composite environment. On the basis of the Born-Markov approximation, we derive a master equation for the reduction of that dynamics to the intermediate system alone. In distinction to an earlier paper (Moreno et al 2015 Phys. Rev. A 92, 030104. (doi:10.1103/PhysRevA.92.030104)), where we discussed the stabilizing effect of the far environment on the decoherence in the central system, we focus here on the possibility of using the measurable coherences in the central system for probing the open quantum dynamics in the intermediate system. We illustrate our results for the case of chaotic dynamics in the near environment, where we compare random matrix simulations with our analytical result.

20.
Neuroscience ; 325: 30-8, 2016 06 14.
Artículo en Inglés | MEDLINE | ID: mdl-27012611

RESUMEN

Brain tauopathies are characterized by abnormal processing of tau protein. While somatodendritic tau mislocalization has attracted considerable attention in tauopathies, the role of tau pathology in axonal transport, connectivity and related dysfunctions remains obscure. We have previously shown using the squid giant synapse that presynaptic microinjection of recombinant human tau protein (htau42) results in failure of synaptic transmission. Here, we evaluated molecular mechanisms mediating this effect. Thus, the initial event, observed after htau42 presynaptic injection, was an increase in transmitter release. This event was mediated by calcium release from intracellular stores and was followed by a reduction in evoked transmitter release. The effect of htau42 on synaptic transmission was recapitulated by a peptide comprising the phosphatase-activating domain of tau, suggesting activation of phosphotransferases. Accordingly, findings indicated that htau42-mediated toxicity involves the activities of both GSK3 and Cdk5 kinases.


Asunto(s)
Terminales Presinápticos/efectos de los fármacos , Terminales Presinápticos/metabolismo , Transmisión Sináptica/efectos de los fármacos , Proteínas tau/toxicidad , Potenciales de Acción/efectos de los fármacos , Animales , Calcio/metabolismo , Quinasa 5 Dependiente de la Ciclina/metabolismo , Decapodiformes , Glucógeno Sintasa Quinasa 3 beta/metabolismo , Humanos , Receptores de Inositol 1,4,5-Trifosfato/metabolismo , Canal Liberador de Calcio Receptor de Rianodina/metabolismo
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