The objective of this review is to provide a broad overview of the advantages and limitations of carbon-based nanomaterials with respect to analytical chemistry. Aiming to illustrate the impact of ...nanomaterials on the development of novel analytical applications, developments reported in the 2005–2010 period have been included and divided into sample preparation, separation, and detection. Within each section, fullerenes, carbon nanotubes, graphene, and composite materials will be addressed specifically. Although only briefly discussed, included is a section highlighting nanomaterials with interesting catalytic properties that can be used in the design of future devices for analytical chemistry.
A
bstract
The search for dark matter weakly interacting massive particles with noble liquids has probed masses down and below a GeV/
c
2
. The ultimate limit is represented by the experimental ...threshold on the energy transfer to the nuclear recoil. Currently, the experimental sensitivity has reached a threshold equivalent to a few ionization electrons. In these conditions, the contribution of a Bremsstrahlung photon or a so-called Migdal electron due to the sudden acceleration of a nucleus after a collision might be sizable. In the present work, we use a Bayesian approach to study how these effects can be exploited in experiments based on liquid argon detectors. In particular, taking inspiration from the DarkSide-50 public spectra, we develop a simulated experiment to show how the Migdal electron and the Bremsstrahlung photon allow to push the experimental sensitivity down to masses of 0.1 GeV
/c
2
, extending the search region for dark matter particles of previous results. For these masses we estimate the effect of the Earth shielding that, for strongly interacting dark matter, makes any detector blind. Finally, we show how the sensitivity scales for higher exposure.
We report a novel and innovative electrochemical paper-based immunocapture assay (EPIA) to address the need for ultrasensitive detection of emerging pollutants without regulatory status and whose ...effects on environment and human health are not completely yet understood. In particular, we present the application of this system toward highly sensitive detection of the emerging pollutant ethinyl estradiol (EE2). The EPIA approach is based on the use of paper microzones modified with silica nanoparticles (SNs) and anti-EE2 specific antibodies for capture and preconcentration of EE2 from river water samples. After the preconcentration procedure, the paper microzones are placed onto a screen-printed carbon electrode modified with electrochemically reduced graphene (RG). The bound EE2 is subsequently desorbed adding a diluted solution of sulfuric acid on the paper microzones. Finally, recovered EE2 is electrochemically detected by OSWV. The proposed novel methodology showed an appropriate LOD and linear range for the quantification of EE2 for water samples with different origins. The nonsophisticated equipment required, the adequate recovery values obtained (from 97% to 104%, with a RSD less than 4.9%), and the appropriate LOD and linear range value (0.1 ng L–1 and 0.5–120 ng L–1, respectively) achieved by our immunocapture sensor present significant analytical figures of merit, particularly when the routine quantification of EE2 is considered. In addition, our system was based on electrochemical paper-based technology, which allows obtainment of portable, easy-to-use, inexpensive, and disposable devices. The EPIA can also serve as a general-purpose immunoassay platform applicable to quantitation of other drugs and emerging pollutants in environmental samples.
Voltage-dependent anion channels (VDACs) are expressed in three isoforms, with common channeling properties and different roles in cell survival. We show that VDAC1 silencing potentiates apoptotic ...challenges, whereas VDAC2 has the opposite effect. Although all three VDAC isoforms are equivalent in allowing mitochondrial Ca(2+) loading upon agonist stimulation, VDAC1 silencing selectively impairs the transfer of the low-amplitude apoptotic Ca(2+) signals. Co-immunoprecipitation experiments show that VDAC1, but not VDAC2 and VDAC3, forms complexes with IP(3) receptors, an interaction that is further strengthened by apoptotic stimuli. These data highlight a non-redundant molecular route for transferring Ca(2+) signals to mitochondria in apoptosis.
Hilbert spectral analysis (HSA) is used to characterize the time evolution of non-stationary power system oscillations following large perturbations. Using an analytical procedure based on the ...Hilbert-Huang Technique (HHT), data from transient stability simulations are decomposed into a finite number of time-varying oscillating components that can be associated with different time scales. Hilbert analysis is then utilized to characterize the time evolution of critical components giving rise to the observed oscillations. The objectives of this study are to obtain information of a quantitative nature on nonlinear processes in power system oscillatory phenomena and assess the applicability of the developed procedures to track the evolving dynamics of critical system modes. A six-area, 377-machine power system is analyzed to examine the onset of nonlinear, non-stationary behavior. Examples of the developed procedures to detect and quantify the strength of nonlinear interaction in power system behavior and to estimate the distribution of the non-stationarity are provided
J.L. Vincent, and Dear Editor (self) Elect—Artificial Intelligence (AI), We read with interest the letter reported by the two high-level researchers on behalf of the “self-electing” future Editor in ...Chief of the prestigious Critical Care journal 1. ...the AI Editorial take-over may need a while, and the process will certainly need a gradual secondment with close supervision by people with great Editorial experience. ...asking the peer-review process to address also the issue of author’s self-referencing would be certainly too much, considering their work is done on voluntary basis and that priority is given to the critical evaluation of the manuscript quality over the appropriateness of references.
Elevated mammalian target of rapamycin (mTOR) signaling has been found in Alzheimer's disease (AD) patients and is linked to diabetes and aging, two known risk factors for AD. However, whether ...hyperactive mTOR plays a role in the cognitive deficits associated with AD remains elusive. Here, we genetically reduced mTOR signaling in the brains of Tg2576 mice, a widely used animal model of AD. We found that suppression of mTOR signaling reduced amyloid-β deposits and rescued memory deficits. Mechanistically, the reduction in mTOR signaling led to an increase in autophagy induction and restored the hippocampal gene expression signature of the Tg2576 mice to wild-type levels. Our results implicate hyperactive mTOR signaling as a previous unidentified signaling pathway underlying gene-expression dysregulation and cognitive deficits in AD. Furthermore, hyperactive mTOR signaling may represent a molecular pathway by which aging contributes to the development of AD.
•This paper introduces a graph spectral clustering and visualization method based on similarity network fusion analysis.•The proposed framework exploits the network structure to jointly analyze ...system dynamics and network connectivity, a feature often absent in purely data-driven analysis techniques.•Due to its analytical structure and simplicity, it facilitates the integration or fusion of multiple types of measurements, leading to the identification of reduced-order models.•Combined with the graph community structure concept, the proposed framework facilitates the identification of significant buses and transmission branches.•Application studies investigate the integration, analysis, and visualization of data in a practical test system.
Integrating data from different types or modalities poses an increasingly significant challenge in system monitoring. This paper presents a method for graph spectral clustering and data fusion rooted in the concept of similarity network functions. The proposed approach aims to identify a reduced-order model (a coarse-grained representation) and determine influential variables in system dynamics, streamlining the integration of diverse data types. This is accomplished through a systematic dynamic framework for data fusion formulated based on diffusion geometry and Laplacian embedding of similarity networks. The statistical properties of Markov processes are leveraged in this approach to construct a similarity network or graph for each data type or information to gain a more comprehensive understanding of relationships and patterns within the underlying data. Integrating the proposed approach with the concept of graph community aids in identifying crucial buses for monitoring and analysis. The paper discusses practical considerations related to the application of spectral analysis techniques and presents improvements upon previous work. It also highlights promising methodologies for robustly addressing the challenges posed by investigating the multimodal attributes of data.
Detailed simulation studies conducted on a 14-machine, 58-bus test system illustrate the effectiveness of diffusion-based similarity network function techniques.
We report a microfluidic immunosensor for the electrochemical determination of IgG antibodies anti-Toxocara canis (IgG anti-T. canis). In order to improve the selectivity and sensitivity of the ...sensor, core-shell gold-ferric oxide nanoparticles (AuNPs@Fe3O4), and ordered mesoporous carbon (CMK-8) in chitosan (CH) were used. IgG anti-T. canis antibodies detection was carried out using a non-competitive immunoassay, in which excretory secretory antigens from T. canis second-stage larvae (TES) were covalently immobilized on AuNPs@Fe3O4. CMK-8-CH and AuNPs@Fe3O4 were characterized by transmission electron microscopy, scanning electron microscopy, energy dispersive spectrometry, cyclic voltammetry, electrochemical impedance spectroscopy, and N2 adsorption-desorption isotherms.
Antibodies present in serum samples immunologically reacted with TES, and then were quantified by using a second antibody labeled with horseradish peroxidase (HRP-anti-IgG). HRP catalyzes the reduction from H2O2 to H2O with the subsequent oxidation of catechol (H2Q) to p-benzoquinone (Q). The enzymatic product was detected electrochemically at _100 mV on a modified sputtered gold electrode. The detection limit was 0.10 ng mL−1, and the coefficients of intra- and inter-assay variation were less than 6%, with a total assay time of 20 min. As can be seen, the electrochemical immunosensor is a useful tool for in situ IgG antibodies anti-T. canis determination.
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•Antigens from T. canis (TES) were covalently immobilized in core-shell gold-ferric oxide nanoparticles (AuNPs@Fe3O4).•For increase the sensitivity, the gold electrode was modified with an ordered mesoporous carbon (CMK-8) in chitosan (CH).•IgG anti-T. canis antibodies detection was carried out using a non-competitive immunoassay.•This is the first electrochemical microfluidic immunosensor reported for IgG anti-T. canis antibodies detection.
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