The general design principle for developing luminescent redox indicators based on photoinduced electron transfer is described. The first part of the review introduces colorimetric and fluorimetric ...redox indicators. The second part of the review highlights recent developments regarding molecular luminescent redox switches and logic gates. Potential future applications in biology, environmental analysis, biomedical diagnostics, corrosion science and materials science are mentioned.
The exploitation of photoinduced electron transfer as a general design principle for the development of luminescent redox indicators and logic gates is described. Potential future applications in biology, environmental analysis, biomedical diagnostics, corrosion science and materials science are mentioned.
The concept of a lab-on-a-molecule, which was proposed just short of two decades ago, has captured the imagination of scientists. From originally being proposed as an AND logic gate driven by three ...chemical inputs as a direct way of detecting congregations of chemical species, the definition of what constitutes a lab-on-a-molecule has broadened over the years. In this review, molecules that can detect multiple analytes by fluorescence, among other techniques, are reviewed and discussed, in the context of molecular logic and multi-analyte sensing. The review highlights challenges and suggestions for moving the frontiers of research in this field to the next dimension.
A solid-bound 4-amino-1,8-naphthalimide AND logic gate, responsive to acidity and oxidisability, emits a green fluorescence immobilised on polyethyleneglycol-polystyrene (TentaGel) beads in water.
Spatial EEG filters are widely used to isolate event-related potential (ERP) components. The most commonly used spatial filters (e.g., the average reference and the surface Laplacian) are ..."stationary." Stationary filters are conceptually simple, easy to use, and fast to compute, but all assume that the EEG signal does not change across sensors and time. Given that ERPs are intrinsically nonstationary, applying stationary filters can lead to misinterpretations of the measured neural activity. In contrast, "adaptive" spatial filters (e.g., independent component analysis, ICA; and principal component analysis, PCA) infer their weights directly from the spatial properties of the data. They are, thus, not affected by the shortcomings of stationary filters. The issue with adaptive filters is that understanding how they work and how to interpret their output require advanced statistical and physiological knowledge. Here, we describe a novel, easy-to-use, and conceptually simple adaptive filter (local spatial analysis, LSA) for highlighting local components masked by large widespread activity. This approach exploits the statistical information stored in the trial-by-trial variability of stimulus-evoked neural activity to estimate the spatial filter parameters adaptively at each time point. Using both simulated data and real ERPs elicited by stimuli of four different sensory modalities (audition, vision, touch, and pain), we show that this method outperforms widely used stationary filters and allows to identify novel ERP components masked by large widespread activity. Implementation of the LSA filter in MATLAB is freely available to download.
EEG spatial filtering is important for exploring brain function. Two classes of filters are commonly used: stationary and adaptive. Stationary filters are simple to use but wrongly assume that stimulus-evoked EEG responses (ERPs) are stationary. Adaptive filters do not make this assumption but require solid statistical and physiological knowledge. Bridging this gap, we present local spatial analysis (LSA), an adaptive, yet computationally simple, spatial filter based on linear regression that separates local and widespread brain activity (https://www.iannettilab.net/lsa.html or https://github.com/rorybufacchi/LSA-filter).
ABSTRACT The potentially hazardous asteroid (185851) 2000 DP107 was the first binary near-Earth asteroid to be imaged. Radar observations in 2000 provided images at 75 m resolution that revealed the ...shape, orbit, and spin-up formation mechanism of the binary. The asteroid made a more favorable flyby of the Earth in 2008, yielding images at 30 m resolution. We used these data to obtain shape models for the two components and to improve the estimates of the mutual orbit, component masses, and spin periods. The primary has a sidereal spin period of 2.7745 0.0007 hr and is roughly spheroidal with an equivalent diameter of 863 m . It has a mass of kg and a density of 1381 244 kg m−3. It exhibits an equatorial ridge similar to the (66391) 1999 KW4 primary; however, the equatorial ridge in this case is not as regular and has a ∼300 m diameter concavity on one side. The secondary has a sidereal spin period of 1.77 0.02 days commensurate with the orbital period. The secondary is slightly elongated and has overall dimensions of m (6% uncertainties). Its mass is kg and its density is 1047 230 kg m−3. The mutual orbit has a semimajor axis of 2.659 0.08 km, an eccentricity of 0.019 0.01, and a period of 1.7556 0.0015 days. The normalized total angular momentum of this system exceeds the amount required for the expected spin-up formation mechanism. An increase of angular momentum from non-gravitational forces after binary formation is a possible explanation. The two components have similar radar reflectivity, suggesting a similar composition consistent with formation by spin-up. The secondary appears to exhibit a larger circular polarization ratio than the primary, suggesting a rougher surface or subsurface at radar wavelength scales.
Polyacrylamide hydrogels formed by free radical polymerisation were formed by entrapping anthracene and 4-amino-1,8-naphthalimide fluorescent logic gates based on photoinduced electron transfer (PET) ...and/or internal charge transfer (ICT). The non-covalent immobilisation of the molecules in the hydrogels resulted in semi-solid YES, NOT, and AND logic gates. Two molecular AND gates, examples of Pourbaix sensors, were tested in acidic aqueous methanol with ammonium persulfate, a strong oxidant, and displayed greater fluorescence quantum yields than previously reported. The logic hydrogels were exposed to aqueous solutions with chemical inputs, and the fluorescence output response was viewed under 365 nm UV light. All of the molecular logic gates diffuse out of the hydrogels to some extent when placed in solution, particularly those with secondary basic amines. The study exemplifies an effort of taking molecular logic gates from homogeneous solutions into the realm of solid-solution environments. We demonstrate the use of Pourbaix sensors as pE-pH indicators for monitoring oxidative and acidic conditions, notably for excess ammonium persulfate, a reagent used in the polymerisation of SDS-polyacrylamide gels.
Four naphthalenediimide colorimetric pH indicators were synthesized with N,N-dimethylethyleneamine at the imide positions and with 5- to 7-membered heterocyclic rings at the bay positions, namely ...pyrrolidine, morpholine, piperidine and azepane. The pH indicators are constructed in a modular receptor–spacer–fluorophore–spacer–receptor format based on a photoinduced electron transfer (PET) design. The compounds were studied by UV–visible absorption and steady-state fluorescence spectroscopy in 1:1 (v/v) methanol/water. Brilliant colour changes are observed between pH 2 and 4 due to an internal charge transfer (ICT) mechanism. Fluorescence turn-on enhancements range from 10–37 fold; however, the maximum fluorescence quantum yield in the presence of acid is <0.004, which is below naked eye detection. Hence, from the viewpoint of a human observer, these chemosensors function as colorimetric YES logic gates, and fluorimetric PASS 0 logic gates.
Recent progress in the area of molecular logic, in particular molecules capable of sensing for acidity and oxidizability, are gathered together in this short review. Originally proposed as AND logic ...gates that provide a high fluorescence output when simultaneously protonated and oxidized, the concept has been extended from two-input to three-input variants and to include molecules that function as INHIBIT logic gates. Photochemical concepts such as photoinduced electron transfer (PET) and internal charge transfer (ICT) are exploited as favorite design concepts. This review highlights the evolution of Pourbaix sensors with anthracene, pyrazoline, and naphthalimide fluorophores. Future applications abound in various disciplines from corrosion science, material science, geochemistry to cell imaging.
Few studies have reported the prognosis of human immunodeficiency virus (HIV)‐positive patients followed for a long time in Brazil, particularly those including pre and post‐HAART eras. The ...polymorphisms of interferon (IFN)‐λ4 have been postulated as possibly associated with the pathogenesis of HIV infection. The aim of this study was to describe the incidence and mortality from a cohort of HIV‐positive patients as well as whether IFN‐λ4 gene polymorphisms (SNP rs8099917 and SNP rs12979860) were associated with HIV/acquired immune deficiency syndrome (AIDS) progression. We followed 402 patients for up to 30 years; 347 of them began follow‐up asymptomatic, without any AIDS‐defining opportunistic disease and/or a lymphocytes T CD4+ count of 350 cells/mm3 or lower. We determined the probability of the asymptomatic subjects to remain AIDS‐free, and the risk of death for those entering the study already with an AIDS diagnosis, as well as for subjects developing AIDS during follow‐up. We compared the prognosis of patients with two different polymorphisms for the genes encoding for IFN‐λ4, variants rs8099917 and rs12979860. The follow‐up time of the 347 asymptomatic‐at‐entry subjects was 3687 person‐years. IFN‐λ4 rs8099917 polymorphisms were not associated with AIDS progression, but IFN‐λ4 rs12979860 wild type genotype (CC) was associated with higher mortality compared to CT and TT, with an increased probability of death from AIDS (P = .01). In conclusion, genetic variations in IFN‐λ4 on rs12979860 polymorphisms in HIV‐infected patients may drive mortality risk.
Highlights
This study described the incidence and mortality from a cohort of HIV‐positive patients as well as whether IFN‐λ4 gene polymorphisms (SNP rs8099917 and SNP rs12979860) were associated with HIV/acquired immune deficiency syndrome (AIDS) progression. The results showed that genetic variations in IFN‐λ4 on rs12979860 polymorphisms in HIV‐infected patients may drive mortality risk.
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