Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 60
Filtrar
Más filtros

País/Región como asunto
Tipo del documento
País de afiliación
Intervalo de año de publicación
1.
Small ; : e2405000, 2024 Aug 17.
Artículo en Inglés | MEDLINE | ID: mdl-39152934

RESUMEN

Fiber electronics booms as a new important field but is currently limited by the challenge of finding both highly flexible and conductive fiber electrodes. Here, all-metal fibers based on nanowires are discovered. Silver nanowires are continuously assembled into robust fibers by salt-induced aggregation and then firmly stabilized by plasmonic welding. The nanowire network structures provide them both high flexibility with moduli at the level of MPa and conductivities up to 106 S m-1. They also show excellent electrochemical properties such as low impedance and high electrochemically active surface area. Their stable chronic single-neuron recording is further demonstrated with good biocompatibility in vivo. These new fiber materials may provide more opportunities for the future development of fiber electronics.

2.
World J Surg Oncol ; 22(1): 42, 2024 Feb 03.
Artículo en Inglés | MEDLINE | ID: mdl-38310233

RESUMEN

AIMS: To present a case series of 11 rare uterine tumors resembling ovarian sex cord tumors (UTROSCTs), and review the literature on this topic to offer up-to-date treatment management for UTROSCTs. METHOD: Eight cases from Fujian Cancer Hospital between January 2017 and May 2023 and three patients from Fujian Union Hospital between October 2012 and October 2020 were retrospectively reviewed. All cases were pathologically confirmed as UTROSCTs by two senior and experienced pathologists. Clinical behaviors, medical data, histopathological features, therapy approaches, and survival outcomes were discussed. RESULTS: The median age at initial diagnosis was 53 years (29-70 years). 3 (27.3%) patients were under 40. Seven cases presented with abnormal vaginal bleeding, one with menstrual disorder, one with abnormal vaginal secretion, and two patients were accidentally found by physical examination without any symptoms. Three patients were initially misdiagnosed with endometrial cancer by MRI. Curettage was performed in all cases. Nine of them were well diagnosed by routine curettage, except for two samples, which were identified after surgery. Immunohistochemical biomarkers, such as CD99, Desmin, WT-1, CK, Vimentin, SMA, α-Inhibin, Ki67, CD56, ER, PR, and CR, tend to be positive in UTRO SCs patients. Six patients underwent hysterectomy with bilateral salpingo-oophorectomy. Two cases received a radical hysterectomy with bilateral salpingo-oophorectomy, retroperitoneal lymph node dissection, and omentum dissection. Three UTROSCTs were under observation after mass resection. The median PFS was 24 months (range 1-125 months). CONCLUSION: UTROSCT is a rare mesenchymal tumor with low malignant potential. Treatment modalities should be carefully considered to balance the therapy outcomes and patient needs. Surgery conservative management might be suitable for young women with fertility desires.


Asunto(s)
Neoplasias Endometriales , Neoplasias Ováricas , Neoplasias Uterinas , Humanos , Femenino , Persona de Mediana Edad , Estudios Retrospectivos , Neoplasias Uterinas/diagnóstico , Neoplasias Uterinas/cirugía , Neoplasias Endometriales/cirugía , Neoplasias Ováricas/diagnóstico , Neoplasias Ováricas/cirugía , Histerectomía
3.
Opt Lett ; 48(22): 5851-5854, 2023 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-37966735

RESUMEN

The thermal deformation fitting result of an optical surface is an important factor that affects the reliability of optical-mechanical-thermal integrated analysis. The traditional numerical methods are challenging to balance fitting accuracy and efficiency, especially the insufficient ability to deal with high-order Zernike polynomials. In this Letter, we innovatively proposed an opto-thermal deformation fitting method based on a neural network and a transfer learning to overcome shortcomings of numerical methods. The one-dimensional convolutional neural network (1D-CNN) model, which can represent deformation of the optical surface, is trained with Zernike polynomials as the input and the optical surface sag change as the output, and the corresponding Zernike coefficients are predicted by the identity matrix. Meanwhile, the trained 1D-CNN is further combined with the transfer learning to efficiently fit all thermal deformations of the same optical surface at different temperature conditions and avoids repeated training of the network. We performed thermal analysis on the main mirror of an aerial camera to verify the proposed method. The regression analysis of 1D-CNN training results showed that the determination coefficient is greater than 99.9%. The distributions of Zernike coefficients predicted by 1D-CNN and transfer learning are consistent. We conducted an error analysis on the fitting results, and the average values of the peak-valley, root mean square, and mean relative errors of the proposed method are 51.56%, 60.51, and 45.14% of the least square method, respectively. The results indicate that the proposed method significantly improves the fitting accuracy and efficiency of thermal deformations, making the optical-mechanical-thermal integrated analysis more reliable.

4.
5.
Nature ; 606(7915): E7-E11, 2022 06.
Artículo en Inglés | MEDLINE | ID: mdl-35732757
6.
Sensors (Basel) ; 23(2)2023 Jan 09.
Artículo en Inglés | MEDLINE | ID: mdl-36679554

RESUMEN

The Aquila Optimizer (AO) is a new bio-inspired meta-heuristic algorithm inspired by Aquila's hunting behavior. Adaptive Aquila Optimizer Combining Niche Thought with Dispersed Chaotic Swarm (NCAAO) is proposed to address the problem that although the Aquila Optimizer (AO) has a strong global exploration capability, it has an insufficient local exploitation capability and a slow convergence rate. First, to improve the diversity of populations in the algorithm and the uniformity of distribution in the search space, DLCS chaotic mapping is used to generate the initial populations so that the algorithm is in a better exploration state. Then, to improve the search accuracy of the algorithm, an adaptive adjustment strategy of de-searching preferences is proposed. The exploration and development phases of the NCAAO algorithm are effectively balanced by changing the search threshold and introducing the position weight parameter to adaptively adjust the search process. Finally, the idea of small habitats is effectively used to promote the exchange of information between groups and accelerate the rapid convergence of groups to the optimal solution. To verify the optimization performance of the NCAAO algorithm, the improved algorithm was tested on 15 standard benchmark functions, the Wilcoxon rank sum test, and engineering optimization problems to test the optimization-seeking ability of the improved algorithm. The experimental results show that the NCAAO algorithm has better search performance and faster convergence speed compared with other intelligent algorithms.


Asunto(s)
Águilas , Animales , Algoritmos , Benchmarking , Ingeniería , Heurística
7.
Anal Chem ; 94(45): 15671-15677, 2022 11 15.
Artículo en Inglés | MEDLINE | ID: mdl-36321224

RESUMEN

The sensors based on ion transport in a confined nano-/microchannel (i.e., iontronic sensors) have brought new opportunities for in vivo neurochemical assay, especially for electroinactive molecules. However, the interference on spontaneous neuronal activity induced by the electric field around the sensors has not been addressed. Here, the electric field distribution with a double-barreled micropipette was shrunk and quantified by finite element simulation, which can explain and minimize the influence on spontaneous neuronal activity. The parameters affecting the electric field distribution, including the pore size, applied voltage, and angle degree, were studied to balance the sensitivity and interference on spontaneous neuronal activity. The double-barreled micropipette, as a pH sensor with high selectivity and sensitivity, has been successfully applied to real-time pH sensing in rat brain. This study offers a new way for in vivo monitoring neurochemical dynamics with neuron-compatibility.


Asunto(s)
Neuronas , Animales , Ratas , Simulación por Computador
8.
Opt Express ; 30(6): 8927-8948, 2022 Mar 14.
Artículo en Inglés | MEDLINE | ID: mdl-35299334

RESUMEN

For the requirement of high-precision vertical profile of the polarization and optical properties of natural seawater, a ship-borne variable-FOV, dual-wavelength, polarized ocean lidar system is designed to obtain the volume linear depolarization ratio (VDR), color ratio and optical parameter profiles of seawater. With the high signal-to-noise ratio, which benefits from the high power (355 nm with 120 mJ, 532 nm with 200 mJ) solid-state laser and a photon counting recorder with a sampling rate of 1 GHz, the attenuated backscattered signal of seawater in the western Pacific campaign reaches to the depth of 50 m, where a plankton layer presents. The receiver of lidar is capable of switching to wide and narrow field of view (FOV), respectively, to obtain the lidar attenuation coefficient Klidar, which is in good agreement with the beam attenuation coefficient of seawater c with a narrow FOV and diffuse attenuation coefficient Kd with a wide FOV. Besides, the Klidar, and the VDR, at two wavelengths of 355 nm and 532 nm are compared to explore the possibility of multi-wavelength of laser application in the ocean lidar. The VDR and the color ratio profiles have a desirable correlation with the in-situ measurement of chlorophyll a (Chla) and chromophoric dissolved organic matter (CDOM) profiles, respectively. With the combination of the Klidar, the VDR and the color ratio profiles, measured in different regions and time periods during the campaign, the multi-wavelength and polarization lidar shows its potential to explore various ocean compositions, such as the ocean particles size shape, the species and vertical migration characteristics of planktons, and the profile distribution of the ocean compositions.

9.
Rapid Commun Mass Spectrom ; 36(3): e9218, 2022 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-34740281

RESUMEN

RATIONALE: The challenge of glycan identification due to their structural complexity and diversity has profited enormously from recent developments in mass spectrometry (MS)-related methods. For photodissociation MS, infrared (IR) and ultraviolet (UV) lasers can generate complementary fragment ions, so an effective combination of the two methods may provide rich and valuable fragmentation patterns for glycan analysis. METHODS: A 7.0 T Fourier transform ion cyclotron resonance (FTICR) mass spectrometer equipped with a double-beam laser system was applied for the experiments. 3,5-Diiodo-L-tyrosine was selected as the assistant molecule to form complex ions with ten isomeric disaccharides through electrospray ionization. The complex ions were further isolated and irradiated by IR and UV lasers separately or continuously in the FTICR cell. RESULTS: By combining the two complementary fragment spectra generated from the IR and UV lasers, a clear identification of all the ten isomers was achieved using their binary codes based on their fragmentation patterns. The double-beam method simplifies the experiment by introducing the two lasers sequentially in one experiment, providing richer fragmentation patterns and making the full discrimination easier. CONCLUSIONS: This study demonstrates the capabilities of the combination of IR and UV photodissociation MS in the identification of diverse glycan isomers. The double-beam photodissociation method described here distinguished compositional, configurational and connectivity disaccharide isomers successfully. Compared with the data accumulation method based on separate IR and UV experiments, this method is simpler, faster, more flexible and also characterized by richer fragmentation patterns.

10.
Sensors (Basel) ; 22(5)2022 Feb 27.
Artículo en Inglés | MEDLINE | ID: mdl-35271019

RESUMEN

The sea surface temperature (SST) is a crucial parameter system in climate monitoring. Satellite remote sensing is currently the most common approach for measuring long-term and large-area sea surface temperatures. The SST data measured by the satellite radiometer include the sea surface skin temperature (SSTskin) at a depth of approximately 10 µm. Satellite remote sensing measurement data must be compared and validated with on-site measured data. There are various solutions for on-site measuring instruments; the essential components are usually infrared radiation sensors with radiation output. This paper uses an ordinary integrated infrared thermometer without a radiation output function to remotely measure the sea surface temperature to achieve a high-precision measurement. The scheme of integrating infrared thermometers to measure the sea surface temperature is investigated in this paper. Based on Planck's formula, the bidirectional conversion relationship between temperature and radiation in a certain band is established. The experimental system introduced in this paper uses an integrated infrared thermometer to measure the small blackbody and the target in a cyclic measurement system. We combine it with the sea surface emissivity characteristics and eliminate the influence of sky background radiation on the sea surface to obtain the actual amount of radiation on the sea surface, from which we obtain the actual radiation amount on the sea surface. Accurate SST can be calculated from the actual amount of radiation at the sea surface. The temperature measurement accuracy can reach 0.1 K, allowing it to meet on-site temperature measurement requirements, as well as the comparison measurement requirements confirmed by satellite remote sensing on-site data. There are relatively few products available for sensors with a temperature measurement accuracy of 0.1 K on the market, and temperature measurement equipment with a temperature measurement accuracy of 0.1 K is relatively expensive. Cost is one of the important factors to consider when using in bulk, especially as global warming increases the need for ocean monitoring. The scheme proposed in this paper is beneficial to reduce the volume and weight of measuring instruments, reduce the cost, and promote the large-scale combined application of sea surface temperature change monitoring.

11.
Anal Chem ; 93(26): 9056-9063, 2021 07 06.
Artículo en Inglés | MEDLINE | ID: mdl-34165954

RESUMEN

Both infrared multiphoton dissociation (IRMPD) and ultraviolet photodissociation (UVPD) play important roles in tandem mass spectrometry and the action spectroscopy of organic and biological molecules. A flexible combination of the two methods may provide researchers with more versatile and powerful ion activation/dissociation choices for structural characterization and spectroscopic studies. Here, we report the integration of two tunable lasers with a Fourier transform ion cyclotron resonance mass spectrometer in a confocal mode, which offers multiple capabilities for photon activation/dissociation experiments. The two overlapped beams can be introduced into the cell individually, sequentially, or simultaneously, providing highly flexible and diverse activation schemes. The setup can also measure the UVPD or IRMPD action spectra of fragment ions generated by previous photon dissociation processes. In addition, the multistage tandem-in-time mass spectrometry performance up to MS4, including three different activation methods in a single cell, has also been demonstrated.


Asunto(s)
Ciclotrones , Fotones , Análisis de Fourier , Iones , Rayos Láser , Espectroscopía Infrarroja por Transformada de Fourier
12.
Brain ; 143(7): 2220-2234, 2020 07 01.
Artículo en Inglés | MEDLINE | ID: mdl-32613234

RESUMEN

This study aimed to determine the mutational spectrum of familial Parkinson's disease and sporadic early-onset Parkinson's disease (sEOPD) in a mainland Chinese population and the clinical features of mutation carriers. We performed multiplex ligation-dependent probe amplification assays and whole-exome sequencing for 1676 unrelated patients with Parkinson's disease in a mainland Chinese population, including 192 probands from families with autosomal-recessive Parkinson's disease, 242 probands from families with autosomal-dominant Parkinson's disease, and 1242 sEOPD patients (age at onset ≤ 50). According to standards and guidelines from the American College of Medical Genetics and Genomics, pathogenic/likely pathogenic variants in 23 known Parkinson's disease-associated genes occurred more frequently in the autosomal-recessive Parkinson's disease cohort (65 of 192, 33.85%) than in the autosomal-dominant Parkinson's disease cohort (10 of 242, 4.13%) and the sEOPD cohort (57 of 1242, 4.59%), which leads to an overall molecular diagnostic yield of 7.88% (132 of 1676). We found that PRKN was the most frequently mutated gene (n = 83, 4.95%) and present the first evidence of an SNCA duplication and LRRK2 p.N1437D variant in mainland China. In addition, several novel pathogenic/likely pathogenic variants including LRRK2 (p.V1447M and p.Y1645S), ATP13A2 (p.R735X and p.A819D), FBXO7 (p.G67E), LRP10 (c.322dupC/p.G109Rfs*51) and TMEM230 (c.429delT/p.P144Qfs*2) were identified in our cohort. Furthermore, the age at onset of the 132 probands with genetic diagnoses (median, 31.5 years) was about 14.5 years earlier than that of patients without molecular diagnoses (i.e. non-carriers, median 46.0 years). Specifically, the age at onset of Parkinson's disease patients with pathogenic/likely pathogenic variants in ATP13A2, PLA2G6, PRKN, or PINK1 was significantly lower than that of non-carriers, while the age at onset of carriers with other gene pathogenic/likely pathogenic variants was similar to that of non-carriers. The clinical spectrum of Parkinson's disease-associated gene carriers in this mainland Chinese population was similar to that of other populations. We also detected 61 probands with GBA possibly pathogenic variants (3.64%) and 59 probands with GBA p.L444P (3.52%). These results shed insight into the genetic spectrum and clinical manifestations of Parkinson's disease in mainland China and expand the existing repertoire of pathogenic or likely pathogenic variants involved in known Parkinson's disease-associated genes. Our data highlight the importance of genetic testing in Parkinson's disease patients with age at onset < 40 years, especially in those from families with a recessive inheritance pattern, who may benefit from early diagnosis and treatment.


Asunto(s)
Predisposición Genética a la Enfermedad/genética , Enfermedad de Parkinson/genética , Adulto , Edad de Inicio , Pueblo Asiatico/genética , Estudios de Cohortes , Femenino , Humanos , Masculino , Persona de Mediana Edad
13.
Bioorg Chem ; 108: 104635, 2021 03.
Artículo en Inglés | MEDLINE | ID: mdl-33484940

RESUMEN

Eleven undescribed quinolone alkaloids, pesimquinolones I-S (1-4 and 6-12), as well as eleven known congeners (5 and 13-22), were isolated from the solid culture broth of the fungus Penicillium simplicissimum. Their chemical structures with absolute configurations were established by a combination of NMR spectroscopy, single-crystal X-ray crystallography, and modified Mosher's methods. Pesimquinolones I-K (1-3) represent the first examples of natural occurring quinolone alkaloids that possess a 6/6/6/6 tetracyclic ring system. The anti-inflammatory activities of selected compounds on LPS-induced nitric oxide (NO) production in adherent cells were evaluated. Compounds 1 and 2 showed suppressive effects on the production of NO, with IC50 values of 10.13 and 8.10 µM, respectively.


Asunto(s)
Alcaloides/farmacología , Antiinflamatorios/farmacología , Óxido Nítrico/antagonistas & inhibidores , Penicillium/química , Quinolonas/farmacología , Alcaloides/química , Alcaloides/aislamiento & purificación , Animales , Antiinflamatorios/química , Antiinflamatorios/aislamiento & purificación , Cristalografía por Rayos X , Relación Dosis-Respuesta a Droga , Lipopolisacáridos/antagonistas & inhibidores , Lipopolisacáridos/farmacología , Ratones , Modelos Moleculares , Estructura Molecular , Óxido Nítrico/biosíntesis , Quinolonas/química , Quinolonas/aislamiento & purificación , Células RAW 264.7 , Relación Estructura-Actividad
14.
Hum Mol Genet ; 27(4): 625-637, 2018 02 15.
Artículo en Inglés | MEDLINE | ID: mdl-29294000

RESUMEN

Paroxysmal kinesigenic dyskinesia (PKD) is a heterogeneous movement disorder characterized by recurrent dyskinesia attacks triggered by sudden movement. PRRT2 has been identified as the first causative gene of PKD. However, it is only responsible for approximately half of affected individuals, indicating that other loci are most likely involved in the etiology of this disorder. To explore the underlying causative gene of PRRT2-negative PKD, we used a combination strategy including linkage analysis, whole-exome sequencing and copy number variations analysis to detect the genetic variants within a family with PKD. We identified a linkage locus on chromosome 12 (12p13.32-12p12.3) and detected a novel heterozygous mutation c.956 T>G (p.319 L>R) in the potassium voltage-gated channel subfamily A member 1, KCNA1. Whole-exome sequencing in another 58 Chinese patients with PKD who lacked mutations in PRRT2 revealed another novel mutation in the KCNA1 gene [c.765 C>A (p.255 N>K)] within another family. Biochemical analysis revealed that the L319R mutant accelerated protein degradation via the proteasome pathway and disrupted membrane expression of the Kv1.1 channel. Electrophysiological examinations in transfected HEK293 cells showed that both the L319R and N255K mutants resulted in reduced potassium currents and respective altered gating properties, with a dominant negative effect on the Kv1.1 wild-type channel. Our study suggests that these mutations in KCNA1 cause the Kv1.1 channel dysfunction, which leads to familial PKD. The current study further extended the genotypic spectrum of this disorder, indicating that Kv1.1 channel dysfunction maybe one of the underlying defects in PKD.


Asunto(s)
Distonía/genética , Canal de Potasio Kv.1.1/genética , Adulto , Pueblo Asiatico , Variaciones en el Número de Copia de ADN , Femenino , Células HEK293 , Humanos , Masculino , Persona de Mediana Edad , Mutación/genética , Linaje
15.
J Phys Chem A ; 124(26): 5280-5287, 2020 Jul 02.
Artículo en Inglés | MEDLINE | ID: mdl-32536155

RESUMEN

Ultraviolet photodissociation (UVPD) experiments of protonated tryptamine ([Tryp+H]+) have been implemented by a Fourier transform ion cyclotron resonance (FTICR) mass spectrometer combined with a wavelength-tunable optical parametric oscillator (OPO) laser. UVPD mass spectra under different laser wavelengths have been obtained, in which the dependence of the yield of fragment ions on the laser wavelength was observed. The UVPD spectrum of [Tryp+H]+ has been obtained in the range of 210-310 nm. Besides the previously reported two competitive channels of H loss and NH3 loss, two important channels of losing CH2NH and CH2NH2 units were observed and further studied by UV-UV tandem mass spectrometry and theoretical calculations. Interestingly, results show that the pair of competitive channels of CH2NH loss and CH2NH2 loss are both from the McLafferty-type rearrangement caused by ππ* electronic excited states. After the excitation, the two different dissociation pathways produce two different ion-neutral complexes, respectively. The wavelength-dependent dissociation and the existing competitive channels shown in this study reflect the diversity of UVPD processes of such organic molecules.

16.
Zhonghua Yi Xue Yi Chuan Xue Za Zhi ; 35(6): 908-911, 2018 Dec 10.
Artículo en Zh | MEDLINE | ID: mdl-30512177

RESUMEN

Genetic generalized epilepsies (GGEs) are a group of epilepsy syndromes caused by genetic factors. A few of GGEs conform to the Mendelian patterns, while most of them show polygene inheritance. Researchers initially found that most of the genes associated with GGEs are related to ion channels including voltage-gated sodium channels, potassium channels, calcium channels and chloride channels, and ligand-gated gamma-aminobutyric acid receptor channels. Further researches have shown that certain non-ion channel genes are also related to GGEs, and that de novo mutations and copy number variants also play an important role in the pathogenesis of GGEs. Application of next- and third-generation sequencing promoted delineation of the molecular genetics of the GGEs, but also brought more challenges. Genetic findings have provided an important basis for the elucidation of the pathogenesis, clinical diagnosis and precise treatment of GGEs. This paper provided a review for recent progress made in molecular genetics of GGEs.


Asunto(s)
Epilepsia Generalizada/genética , Investigación Genética , Canales Iónicos/genética , Humanos
17.
Angew Chem Int Ed Engl ; 57(17): 4590-4593, 2018 04 16.
Artículo en Inglés | MEDLINE | ID: mdl-29473274

RESUMEN

A nonintuitive observation of monovalent anion-induced ion current rectification inversion at polyimidazolium brush (PimB)-modified nanopipettes is presented. The rectification inversion degree is strongly dependent on the concentration and species of monovalent anions. For chaotropic anions (for example, ClO4- ), the rectification inversion is easily observed at a low concentration (5 mm), while there is no rectification inversion observed for kosmotropic anions (Cl- ) even at a high concentration (1 m). Moreover, at the specific concentration (for example, 10 mm), the variation of rectification ratio on the type of anions is ranged by Hofmeister series (Cl- ≥NO3- >BF4- >ClO4- >PF6- >Tf2 N- ). Estimation of the electrokinetic charge density (σek ) demonstrates that rectification inversion originates from the charge inversion owing to the over-adsorption of chaotropic monovalent anion. To qualitatively understand this phenomenon, a concentration-dependent adsorption mechanism is proposed.

18.
J Am Chem Soc ; 139(4): 1396-1399, 2017 02 01.
Artículo en Inglés | MEDLINE | ID: mdl-28095691

RESUMEN

Here we report for the first time that ion current rectification (ICR) can be observed at the micrometer scale in symmetric electrolyte solution with polyimidazolium brush (PimB)-modified micropipets, which we call micrometer-scale ion current rectification (MICR). To qualitatively understand MICR, a three-layer model including a charged layer, an electrical double layer, and a bulk layer is proposed, which could also be extended to understanding ICR at the nanoscale. Based on this model, we propose that when charges in the charged layer are comparable with those in the bulk layer, ICR would occur regardless of whether the electrical double layers are overlapped. Finite element simulations based on the solution of Poisson and Nernst-Planck equations and in situ confocal laser scanning microscopy results qualitatively validate the experimental observations and the proposed three-layer model. Moreover, possible factors influencing MICR, including the length of PimB, electrolyte concentration, and the radius of the pipet, are investigated and discussed. This study successfully extends ICR to the micrometer scale and thus opens a new door to the development of ICR-based devices by taking advantage of ease-in-manipulation and designable surface chemistry of micropipets.

19.
Anal Chem ; 89(12): 6794-6799, 2017 06 20.
Artículo en Inglés | MEDLINE | ID: mdl-28516771

RESUMEN

Development of new principles and methods for cerebral ATP assay is highly imperative not only for determining ATP dynamics in brain but also for understanding physiological and pathological processes related to ATP. Herein, we for the first time demonstrate that micrometer scale ion current rectification (MICR) at a polyimidazolium brush-modified micropipette can be used as the signal transduction output for the cerebral ATP assay with a high selectivity. The rationale for ATP assay is essentially based on the competitive binding ability between positively charged polyimidazolium and ATP toward negatively charged ATP aptamer. The method is well responsive to ATP with a good linearity within a concentration range from 5 nM to 100 nM, and high selectivity toward ATP. These properties essentially enable the method to determine the cerebral ATP by combining in vivo microdialysis. The basal dialysate level of ATP in rat brain cortex is determined to be 11.32 ± 2.36 nM (n = 3). This study demonstrates that the MICR-based sensors could be potentially used for monitoring neurochemicals in cerebral systems.


Asunto(s)
Adenosina Trifosfato/análisis , Encéfalo/metabolismo , Técnicas Electroquímicas/métodos , Microdiálisis/métodos , Adenosina Trifosfato/metabolismo , Animales , Aptámeros de Nucleótidos/química , Aptámeros de Nucleótidos/metabolismo , Unión Competitiva , Conductividad Eléctrica , Electrodos , Imidazoles/química , Masculino , Microdiálisis/instrumentación , Polímeros/química , Ratas , Ratas Sprague-Dawley
20.
Opt Express ; 25(13): 13944-13952, 2017 Jun 26.
Artículo en Inglés | MEDLINE | ID: mdl-28788982

RESUMEN

In this article, a novel metamaterial is designed aimed at generating a single electromagnetic hot spot, in order to realize the localization of the incident electromagnetic field at terahertz band, and this kind of metastructure is an ideal candidate for many research fields such as spintronics, nonlinear magnetic response, near-field optics, and optical antenna, etc. The specially tailored metamaterial takes the shape of diabolo with a metal triangle pair connected by a cubic gallium arsenide (GaAs) gap. We demonstrated by simulation that both electric- and magnetic-field of incident THz pulse can be confined in the small GaAs gap when a synchronized femtosecond laser pulse is illuminated. The numerical simulation results show that 2 orders of magnitude of field enhancement can be obtained for a 1-by-1 µm GaAs gap, and the field enhancement factor can also be further improved by tailoring the GaAs gap down to nanometer scale.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA