GNN4FR: A Lossless GNN-based Federated Recommendation Framework

Graph neural networks (GNNs) have gained wide popularity in recommender systems due to their capability to capture higher-order structure information among the nodes of users and items. However, these methods need to collect personal interaction data between a user and the corresponding items and then model them in a central server, which would break the privacy laws such as GDPR. So far, no existing work can construct a global graph without leaking each user's private interaction data (i.e., his or her subgraph). In this paper, we are the first to design a novel lossless federated recommendation framework based on GNN, which achieves full-graph training with complete high-order structure information, enabling the training process to be equivalent to the corresponding un-federated counterpart. In addition, we use LightGCN to instantiate an example of our framework and show its equivalence

Towards Arbitrary Text-driven Image Manipulation via Space Alignment

The recent GAN inversion methods have been able to successfully invert the real image input to the corresponding editable latent code in StyleGAN. By combining with the language-vision model (CLIP), some text-driven image manipulation methods are proposed. However, these methods require extra costs to perform optimization for a certain image or a new attribute editing mode. To achieve a more efficient editing method, we propose a new Text-driven image Manipulation framework via Space Alignment (TMSA). The Space Alignment module aims to align the same semantic regions in CLIP and StyleGAN spaces. Then, the text input can be directly accessed into the StyleGAN space and be used to find the semantic shift according to the text description. The framework can support arbitrary image editing mode without additional cost. Our work provides the user with an interface to control the attributes of a given image according to text input and get the result in real time. Ex tensive experiments demonstrate our superior performance over prior works.Comment: 8 pages, 12 figure

Regeneration behavior of chitosan from ionic liquid using water and alcohols as anti-solvents

While ionic liquids (ILs) have been considered as effective and “green” solvents for biopolymer processing, regeneration of IL-dissolved biopolymers could largely impact biopolymer structure and properties. This study indicates that the reconstitution of chitosan structure during regeneration from 1-ethyl-3-methylimidazolium acetate ([Emim][OAc]) depends on anti-solvent (water, methanol or ethanol) largely. Irrespective of anti-solvent, the chitosan chemical structure was not varied by dissolution or regeneration. With water, the regenerated chitosan had the highest crystallinity index of 54.18%, followed by those with methanol (35.07%) and ethanol (25.65%). Water as an anti-solvent could promote chitosan chain rearrangement, leading to the formation of an ordered aggregated structure and crystallites. Density functional theory (DFT) simulation indicates that the number of hydrogen bonds formed between anti-solvents and [Emim][OAc] was in the order of water > methanol > ethanol. With water used for regeneration, the aggregation and rearrangement of chitosan chains occurred more easily

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

A Fast Colourimetric Assay for Lead Detection Using Label-Free Gold Nanoparticles (AuNPs)

A sensitive colourimetric method for lead (PbII) detection is reported in this paper using a common tripeptide, glutathione (GSH), and label-free gold nanoparticles (AuNPs). A limit of detection of 6.0 ppb in water was achieved and the dynamic linear range was up to 500 ppb. Selectivity over fourteen potential interfering metal ions was tested and most of these metal ions do not interfere with the method

Rapid detection of trace metal ions on microfluidic platforms using gold nanoparticle sensors

The presence of metal ions, especially heavy metals, in various waters at elevated levels can pose a high risk to the environment and human health. Drinking water is one of the major sources that contributes to the daily intake of heavy metals by humans, and thus a rapid, low-cost and sensitive method for detection of heavy metal content in water is desirable. The goals of this study are to develop a chemical method for rapid testing of lead (PbII) ion in water solutions and to incorporate the method into a portable device for potential onsite applications. First, a rapid and sensitive colorimetric method for lead detection has been developed in this study by utilizing the unique optical properties and surface chemistry of gold nanoparticles (GNPs) and glutathione (GSH), which is a peptide used for lead recognition. In the reaction, GSH molecules serve as linkers to coordinate with both PbII and GNPs so as to aggregate the GNPs and thereby change the colour of the assay solution. The colour changes as measured by absorbance at selected wavelengths using UV-Vis spectrometry are proportional to the levels of PbII in aqueous samples, and thus quantification of PbII can be realized. As the reaction is based on label-free GNPs, no pre-modification is required. The limit of detection (LOD) of 6.0 ppb achieved by the method is lower than the maximum acceptable PbII concentrations (10 -15 ppb) in drinking water, indicating its high sensitivity and potential applicability in drinking water testing. The high selectivity for PbII against 10 metal ions has been demonstrated, and several masking agents were evaluated for their effectiveness in reducing potential inferences for an additional four metals. Second, a polydimethylsiloxane (PDMS) microfluidic chip was fabricated and coupled with a portable optical reader specifically designed for GNP probes. This device was first tested for detection of aluminum (AlIII) as a model compound by GNP probes to examine the compatibility of the microfluidic chip with the GNP probes and the sensitivity to the corresponding colour changes of the GNPs. It showed an LOD (1.2 ppm) comparable with that of UV-Vis Spectrometry (1.3 ppm) and operations were simple since only pipetting was required. The prominent feature of the device is that PDMS microfluidic chips are disposable and can be redesigned for other assays as well, such that the label-free GNP probes developed in this study for PbII detection can be possibly integrated in those microfluidic chips in the near future. The use of LED array light sources with controllable wavelengths is another feature to enable multi-analyte capability, which could be examined in the near future.La présence d'ions métalliques en particulier les métaux lourds dans différents types d'eau à des niveaux élevés peut présenter un risque important pour l'environnement et la santé humaine. L'eau potable est l'une des principales sources qui contribuent à l'apport quotidien en métaux lourds chez l'humain, et donc une méthode rapide, peu coûteuse et sensible à la détection des métaux lourds dans l'eau est en grande demande. Les objectifs de cette étude est de développer une méthode chimique pour un dépistage rapide d'ion de plomb (PbII) en phase aqueuse et d'intégrer la méthode dans un dispositif portable à des fins d'applications potentielles sur place. Premièrement, une méthode colorimétrique rapide et sensible à la détection de plomb a été développée dans cette étude en utilisant les propriétés optiques uniques et la chimie de surface des nanoparticules d'or (GNPs) et le glutathion (GSH), qui est un peptide utilisé pour la reconnaissance de plomb. En réaction, les molécules de GSH servent de relieurs à fin de coordonner avec le PbII ainsi que le GNPs de manière à regrouper les sondes GNPs et ainsi changer la couleur du dosage. Les changements de couleur mesurée par absorption à des longueurs d'onde sélectionnées en utilisant la spectrométrie d'UV-Vis sont proportionnels au niveau du PbII dans des échantillons aqueux, permettant ainsi la quantification de PbII. Comme la réaction est basée sur l'utilisation des GNPs non-libellés, pas de pré-modification est requise. La limite de détection (LOD) de 6,0 ppb réalisée par la méthode est inférieure aux concentrations maximales de PbII acceptable (10 à 15 ppb) dans l'eau potable, ce qui indique sa haute sensibilité et applicabilité potentielle en analyse d'eau potable. Une haute sélectivité pour le PbII contre 10 ions métalliques a été démontrée, et plusieurs agents masquant ont été évalués pour leur efficacité dans la réduction des interférences potentielles pour quatre autres métaux. Deuxièmement, une puce microfluidique en polydiméthylsiloxane (PDMS) a été fabriqué et couplé à un lecteur optique portable spécialement conçu pour les sondes de GNPs. Cet appareil a été d'abord testé pour la détection de l'aluminium (AlIII) comme composé modèle, par des sondes de GNPs à fin d'examiner la compatibilité de la puce microfluidique avec les sondes de GNPs et la sensibilité aux changements de couleur correspondante du GNPs. Elle a démontré une LOD comparable (1,2 ppm) à celui de la spectrométrie UV-Vis (1,3 ppm) et les opérations étaient simples puisque seulement le pipetage était nécessaire. L'aspect remarquable du dispositif est que les puces microfluidiques de PDMS sont jetables et peuvent être reformulées pour d'autres dosages ainsi, de sorte que les sondes de GNPs non-libellées développées dans cette étude pour la détection de PbII peuvent être éventuellement intégrés dans des études futures. L'utilisation des sources de lumière à faisceau LED aux longueurs d'onde contrôlables est une autre caractéristique permettant une capacité multi-analyte, qui pourrait être examinée dans un proche avenir

frameinvarianceinfiniteelementformulationsofgeometricallyexactrods

This article is concerned with finite element implementations of the threedimensional geometrically exact rod. The special attention is paid to identifying the condition that ensures the frame invariance of the resulting discrete approximations. From the perspective of symmetry, this requirement is equivalent to the commutativity of the employed interpolation operator I with the action of the special Euclidean group SE(3), or I is SE(3)-equivariant. This geometric criterion helps to clarify several subtle issues about the interpolation of finite rotation. It leads us to reexamine the finite element formulation first proposed by Simo in his work on energy-momentum conserving algorithms. That formulation is often mistakenly regarded as non-objective. However, we show that the obtained approximation is invariant under the superposed rigid body motions, and as a corollary, the objectivity of the continuum model is preserved. The key of this proof comes from the observation that since the numerical quadrature is used to compute the integrals, by storing the rotation field and its derivative at the Gauss points, the equivariant conditions can be relaxed only at these points. Several numerical examples are presented to confirm the theoretical results and demonstrate the performance of this algorithm

A Fast Colourimetric Assay for Lead Detection Using Label-Free Gold Nanoparticles (AuNPs)

A sensitive colourimetric method for lead (PbII) detection is reported in this paper using a common tripeptide, glutathione (GSH), and label-free gold nanoparticles (AuNPs). A limit of detection of 6.0 ppb in water was achieved and the dynamic linear range was up to 500 ppb. Selectivity over fourteen potential interfering metal ions was tested and most of these metal ions do not interfere with the method

Fixed-Point Fluid structure interaction analysis BASED ON geometrically exact approach

The fluid structure interaction analysis for structures exhibiting large deformations is carried out by using a strong coupling method, in which a fixed point method with Aitken's dynamic relaxation is employed to accelerate convergence of the coupling iteration, and geometrically exact beam approach initiated by Simo is adopted to simulate the nonlinear flexible beam models. An improved implicit time integration algorithm is given to improve the computation accuracy of structural dynamics. To verify the validity of the fixed-point method in the compressible flows which is usually used in incompressible fluid, it is applied for flutter analysis of AGARD 445.6 wing in the transonic regime. The case of flow-induced vibration of a flexible beam demonstrates that the approach based on geometrically exact beam theory is suitable for the fluid structure interaction analysis and the fixed-point method with Aitken's relaxation is of great efficiency and robustness in the FSI computation

Leaf Traits and Resource Use Efficiencies of 19 Woody Plant Species in a Plantation in Fangshan, Beijing, China

Plantations are typically monocultures, which limits their sustainability. Therefore, understanding acclimatization strategies and resource use efficiencies in plant species and life forms aids the improvement of vegetation diversity and ecological functions. Here, 19 species from forest plantations in Fangshan, Beijing, China were studied. We determined their net photosynthetic (Pn), and transpiration rates (E), light response curve, stomatal conductance (gs), and leaf nitrogen (N) content. We analyzed the leaf N content (Nmass), specific leaf area (SLA), maximum net photosynthetic rate (Pnmax), water use (WUE), nitrogen use (NUE), and carbon use (CUE) efficiencies and connected them with both species and life forms. Pnmax, SLA, Nmass, WUE, NUE, and CUE significantly differed among species. Evergreen conifers had the lowest SLA and Nmass but the highest WUE and CUE. Evergreen coniferous trees had lower SLA, Nmass, Pnmax, and NUE but higher WUE than deciduous trees and shrubs. The SLA, Nmass, and Pnmax of nitrogen-fixing plants were the highest. A correlation analysis revealed that WUE was positively correlated with CUE and negatively correlated with NUE. Moreover, WUE was negatively correlated with Nmass and SLA. These insights into the adaptability differences of woody plant species and life forms provide a scientific basis for the selection of appropriate species for sustainable forest plantations