Graph Neural Networks for Parkinson's Disease Monitoring and Alerting.

Graph neural networks (GNNs) have been increasingly employed in the field of Parkinson's disease (PD) research. The use of GNNs provides a promising approach to address the complex relationship between various clinical and non-clinical factors that contribute to the progression of PD. This review paper aims to provide a comprehensive overview of the state-of-the-art research that is using GNNs for PD. It presents PD and the motivation behind using GNNs in this field. Background knowledge on the topic is also presented. Our research methodology is based on PRISMA, presenting a comprehensive overview of the current solutions using GNNs for PD, including the various types of GNNs employed and the results obtained. In addition, we discuss open issues and challenges that highlight the limitations of current GNN-based approaches and identify potential paths for future research. Finally, a new approach proposed in this paper presents the integration of new tasks for the engineering of GNNs for PD monitoring and alert solutions.

A high-performance capillary-fed electrolysis cell promises more cost-competitive renewable hydrogen.

Renewable, or green, hydrogen will play a critical role in the decarbonisation of hard-to-abate sectors and will therefore be important in limiting global warming. However, renewable hydrogen is not cost-competitive with fossil fuels, due to the moderate energy efficiency and high capital costs of traditional water electrolysers. Here a unique concept of water electrolysis is introduced, wherein water is supplied to hydrogen- and oxygen-evolving electrodes via capillary-induced transport along a porous inter-electrode separator, leading to inherently bubble-free operation at the electrodes. An alkaline capillary-fed electrolysis cell of this type demonstrates water electrolysis performance exceeding commercial electrolysis cells, with a cell voltage at 0.5 A cm-2 and 85 °C of only 1.51 V, equating to 98% energy efficiency, with an energy consumption of 40.4 kWh/kg hydrogen (vs. ~47.5 kWh/kg in commercial electrolysis cells). High energy efficiency, combined with the promise of a simplified balance-of-plant, brings cost-competitive renewable hydrogen closer to reality.

A Novel Approach to Image Recoloring for Color Vision Deficiency.

In this paper, a novel method to modify color images for the protanopia and deuteranopia color vision deficiencies is proposed. The method admits certain criteria, such as preserving image naturalness and color contrast enhancement. Four modules are employed in the process. First, fuzzy clustering-based color segmentation extracts key colors (which are the cluster centers) of the input image. Second, the key colors are mapped onto the CIE 1931 chromaticity diagram. Then, using the concept of confusion line (i.e., loci of colors confused by the color-blind), a sophisticated mechanism translates (i.e., removes) key colors lying on the same confusion line to different confusion lines so that they can be discriminated by the color-blind. In the third module, the key colors are further adapted by optimizing a regularized objective function that combines the aforementioned criteria. Fourth, the recolored image is obtained by color transfer that involves the adapted key colors and the associated fuzzy clusters. Three related methods are compared with the proposed one, using two performance indices, and evaluated by several experiments over 195 natural images and six digitized art paintings. The main outcomes of the comparative analysis are as follows. (a) Quantitative evaluation based on nonparametric statistical analysis is conducted by comparing the proposed method to each one of the other three methods for protanopia and deuteranopia, and for each index. In most of the comparisons, the Bonferroni adjusted p-values are <0.015, favoring the superiority of the proposed method. (b) Qualitative evaluation verifies the aesthetic appearance of the recolored images.

Electronic structure modelling of the edge-functionalisation of graphene by MnxOy particles.

The use of graphenic carbon is attractive as a basal or intermediate support for catalytic particles in advanced catalytic electrodes. This popularity is motivated by its excellent electrical properties and ability to form foliated conformal coatings of exceptional surface area and flexibility. Surface- and edge-functionalisation of graphene sheets affords diverse routes to the covalent attachment of candidate catalytic species. Of particular interest to advanced water oxidation is the possibility of covalent attachment of MnxOy species partially recapitulating the chemistry of the Mn4O5Ca active site of Photosystem II (PSII), which achieves the four-electron oxidation of water under physiological conditions. Here, we report aperiodic density functional theory (DFT) investigations of candidate attachment geometries for a variety of manganese oxide particles to graphene sheets. We find that the flexibility of graphene sheets as well as the conformational degrees of freedom of candidate edge functionalisation permits a large variety of realistic attachment geometries that can act as attachment sites for molecular manganese-oxide species or nuclei for the growth of periodic manganese oxides. We find that substantially simplified models of graphene attachment afford an excellent compromise between computational efficiency, tractability, and accuracy, and characterise the accuracy of these models in detail.

Gortex-Based Gas Diffusion Electrodes with Unprecedented Resistance to Flooding and Leaking.

A significant and long-standing problem in electrochemistry has demanded the need for gas diffusion electrodes that are "flood-proof" and "leak-proof" when operated with a liquid electrolyte. The absence of a solution to this problem has, effectively, made it unviable to use gas diffusion electrodes in many electrochemical manufacturing processes, especially as " gas-depolarized" counter electrodes with significantly decreased energy consumption. In this work, Gortex membranes (also known as expanded PTFE or ePTFE) have been studied as novel, leak-proof substrates for gas diffusion electrodes [PTFE = poly(tetrafluoroethylene)]. We report the fabrication, characterization, and operation of gas diffusion electrodes comprising finely pored Gortex overcoated with 10% Pt on Vulcan XC72, PTFE binder, and a fine Ni mesh as a current carrier. Capillary flow porometry indicated that the electrodes only flooded/leaked when the excess of pressure on their liquid-side over their gas-side was 5.7 atm. This is more than an order of magnitude greater than any previous gas diffusion electrode. The Gortex electrodes were tested as hydrogen- and oxygen-depolarized anodes and cathodes in an alkaline fuel cell in which the liquid electrolyte was pressurized to 0.5-1.5 atm above the gas pressures. Despite the record high electrolyte pressure, the electrodes, which had Pt loadings of only 0.075 mg Pt/cm2, exhibited notable activity over 2 d of continuous, leak-free operation. Under the applied liquid pressure, the fuel cell also overcame all of the key technical challenges that have hindered the adoption of alkaline fuel cells to date. The high activity and unprecedented resistance to leaking/flooding exhibited by these electrodes, even when subjected to large liquid electrolyte overpressures under gas depolarization conditions, provide an important advance with far-reaching implications for electrochemical manufacturing.

Electronic structure origin of conductivity and oxygen reduction activity changes in low-level Cr-substituted (La,Sr)MnO3.

The electronic structure of the (La(0.8)Sr(0.2))(0.98)Mn(1-x)Cr(x)O3 model series (x = 0, 0.05, or 0.1) was measured using soft X-ray synchrotron radiation at room and elevated temperature. O K-edge near-edge X-ray absorption fine structure (NEXAFS) spectra showed that low-level chromium substitution of (La,Sr)MnO3 resulted in lowered hybridisation between O 2p orbitals and M 3d and M 4sp valance orbitals. Mn L3-edge resonant photoemission spectroscopy measurements indicated lowered Mn 3d-O 2p hybridisation with chromium substitution. Deconvolution of O K-edge NEXAFS spectra took into account the effects of exchange and crystal field splitting and included a novel approach whereby the pre-peak region was described using the nominally filled t(2g) ↑ state. 10% chromium substitution resulted in a 0.17 eV lowering in the energy of the t(2g) ↑ state, which appears to provide an explanation for the 0.15 eV rise in activation energy for the oxygen reduction reaction, while decreased overlap between hybrid O 2p-Mn 3d states was in qualitative agreement with lowered electronic conductivity. An orbital-level understanding of the thermodynamically predicted solid oxide fuel cell cathode poisoning mechanism involving low-level chromium substitution on the B-site of (La,Sr)MnO3 is presented.

In situ growth of nanoparticles through control of non-stoichiometry.

Surfaces decorated with uniformly dispersed catalytically active nanoparticles play a key role in many fields, including renewable energy and catalysis. Typically, these structures are prepared by deposition techniques, but alternatively they could be made by growing the nanoparticles in situ directly from the (porous) backbone support. Here we demonstrate that growing nano-size phases from perovskites can be controlled through judicious choice of composition, particularly by tuning deviations from the ideal ABO3 stoichiometry. This non-stoichiometry facilitates a change in equilibrium position to make particle exsolution much more dynamic, enabling the preparation of compositionally diverse nanoparticles (that is, metallic, oxides or mixtures) and seems to afford unprecedented control over particle size, distribution and surface anchorage. The phenomenon is also shown to be influenced strongly by surface reorganization characteristics. The concept exemplified here may serve in the design and development of more sophisticated oxide materials with advanced functionality across a range of possible domains of application.

On the systematic development of fast fuzzy vector quantization for grayscale image compression.

In this paper we propose a learning mechanism to systematically design fast fuzzy clustering-based vector quantizers. Although the utilization of fuzzy clustering in vector quantization is able to reduce the dependence on initialization, it finally obtains high computational cost. This problem has been investigated by many researchers. So far, the most widely used solution is to equip the quantizer with specialized strategies for the smooth transition from fuzzy to crisp conditions. Hereby, we propose an enhanced solution to that problem. In our contribution we combine three different learning modules. The first one concerns the reduction of the number of codewords that are affected by a specific training pattern. The second one acts to reduce the number of training patterns involved in the design process. The sequential implementation of the above two modules manages to significantly reduce the computational cost of the quantizer. However, the potential risk related to the implementation of the first module is the high probability to generate small and badly delineated clusters. To handle this problem we apply, in the third module, a novel cluster distortion equalization process, according to which the codewords of small clusters are moved to the neighborhood of large ones in order to increase their size and become more competitive, obtaining a better local minimum. The proposed algorithm is rigorously evaluated and compared to other sophisticated methods in terms of grayscale image compression.

Zn-Zn porphyrin dimer-sensitized solar cells: toward 3-D light harvesting.

Zn-Zn porphyrin dimers have been incorporated into thin dye-sensitized solar cells (DSSCs) to boost their light harvesting efficiency. The photoexcited dimers show efficient and fast electron injection into TiO(2) indicating that both photoexcited chromophores contribute to current generation. The improved light harvesting ability coupled to enhanced DSSC performance demonstrates the potential of 3-D light harvesting arrays as next generation light harvesters for artificial solar energy conversion systems.

New nonlinear multivariable model shows the relationship between central corneal thickness and HRTII topographic parameters in glaucoma patients.

PURPOSE: In this paper a new nonlinear multivariable regression method is presented in order to investigate the relationship between the central corneal thickness (CCT) and the Heidelberg Retina Tomograph (HRTII) optic nerve head (ONH) topographic measurements, in patients with established glaucoma. METHODS: Forty nine eyes of 49 patients with glaucoma were included in this study. Inclusion criteria were patients with (a) HRT II ONH imaging of good quality (SD < 30 mum), (b) reliable Humphrey visual field tests (30-2 program), and (c) bilateral CCT measurements with ultrasonic contact pachymetry. Patients were classified as glaucomatous based on visual field and/or ONH damage. The relationship between CCT and topographic parameters was analyzed by using the new nonlinear multivariable regression model. RESULTS: In the entire group, CCT was 549.78 +/- 33.08 mum (range: 484-636 mum); intraocular pressure (IOP) was 16.4 +/- 2.67 mmHg (range: 11-23 mmHg); MD was -3.80 +/- 4.97 dB (range: 4.04 - [-20.4] dB); refraction was -0.78 +/- 2.46 D (range: -6.0 D to +3.0 D). The new nonlinear multivariable regression model we used indicated that CCT was significantly related (R(2) = 0.227, p < 0.01) with rim volume nasally and type of diagnosis. CONCLUSIONS: By using the new nonlinear multivariable regression model, in patients with established glaucoma, our data showed that there is a statistically significant correlation between CCT and HRTII ONH structural measurements, in glaucoma patients.

A surface-attached Ru complex operating as a rapid bistable molecular switch.

An electrochemically bistable ruthenium polypyridyl complex was immobilised on platinum electrodes via amide condensation with an amine-terminated self-assembled thiol monolayer and underwent rapid electron transfer-induced linkage isomerism.