A Mechanistic Derivation of The Monod Equation For Biofilm in Porous Media

A mechanistic derivation of the Monod bioreaction equation is presented. The numerical model developed for this derivation involves four processes. 1)On the pore scale, substrate diffuses from the bulk aqueous phase crossing a diffusion boundary layer to the stationary biofilm. 2) On the biofilm scale, the substrate concentration is uniform in the Extracellular Polymeric Substance (EPS) matrix, which equals to that at the biofilm surface. 3) On the microscale, substrates diffuse from the EPS matrix through the EPS layer towards each spherical bacterial cell. 4) Then substrates transport across the cell membrane and react within the microbe for biological reactions. In this numerical model, the derivation incorporates growth kinetics for the bacterial cells and production kinetics for the EPS. The evolution of biofilms and mass transfer processes are simulated under nutrient-limiting and laminar flow conditions. Model parameter sensitivity is examined using data from Reardon et al. (2000), indicating that the diffusive transport of substrate from the aqueous phase to the biofilm is not the most limiting process

Structure-Thermodynamics-Antioxidant Activity Relationships of Selected Natural Phenolic Acids and Derivatives: An Experimental and Theoretical Evaluation

Phenolic acids and derivatives have potential biological functions, however, little is known about the structure-activity relationships and the underlying action mechanisms of these phenolic acids to date. Herein we investigate the structure-thermodynamics-antioxidant relationships of 20 natural phenolic acids and derivatives using DPPH• scavenging assay, density functional theory calculations at the B3LYP/6-311++G(d,p) levels of theory, and quantitative structure-activity relationship (QSAR) modeling. Three main working mechanisms (HAT, SETPT and SPLET) are explored in four micro-environments (gas-phase, benzene, water and ethanol). Computed thermodynamics parameters (BDE, IP, PDE, PA and ETE) are compared with the experimental radical scavenging activities against DPPH•. Available theoretical and experimental investigations have demonstrated that the extended delocalization and intra-molecular hydrogen bonds are the two main contributions to the stability of the radicals. The C = O or C = C in COOH, COOR, C = CCOOH and C = CCOOR groups, and orthodiphenolic functionalities are shown to favorably stabilize the specific radical species to enhance the radical scavenging activities, while the presence of the single OH in the ortho position of the COOH group disfavors the activities. HAT is the thermodynamically preferred mechanism in the gas phase and benzene, whereas SPLET in water and ethanol. Furthermore, our QSAR models robustly represent the structure-activity relationships of these explored compounds in polar media. http://dx.doi.org/10.1371/journal.pone.012127

Seeing is believing: in situ/operando optical microscopy for probing electrochemical energy systems

This review discusses a range of in situ/operando techniques based on optical microscopy reported in literatures for studying electrochemical energy systems. Compared to other techniques (scanning probe microscopy, electron microscopy, X-ray microscopy), optical microscopy offers many advantages including the simplicity of the instrument and operation, cost effectiveness, and nondestructive nature. In the past few decades, significant advances in the field of optical microscopy have been made, enabling new opportunities of more elaborate studies on electrochemical energy systems. Herein, different methodologies are compared, with the emphasis on experimental setup designs and findings, to illustrate their aptness

Bio-Based Epoxy Resin from Epoxidized Soybean Oil

Epoxidized soybean oil (ESO) is the oxidation product of soybean oil with hydrogen peroxide and either acetic or formic acid obtained by converting the double bonds into epoxy groups, which is non-toxic and of higher chemical reactivity. ESO is mainly used as a green plasticizer for polyvinyl chloride, while the reactive epoxy groups imply its great potential in both the monomer synthesis and the polymer preparation fields. Functional polymers are obtained by different kinds of reactions of the ESO with co-monomers and/or initiators shown in this chapter. The emphasis is on ESO based epoxy cross-linked polymers which recently gained strong interest and allowed new developments especially from both an academic point of view and an industrial point of view. It is believed that new ring-opening reagents may facilitate the synthesis of good structural ESO based materials

UoR at SemEval-2020 task 8: Gaussian mixture modelling (GMM) based sampling approach for multi-modal memotion analysis

Memes are widely used on social media. They usually contain multi-modal information such as images and texts, serving as valuable data sources to analyse opinions and sentiment orientations of online communities. The provided memes data often face an imbalanced data problem, that is, some classes or labelled sentiment categories significantly outnumber other classes. This often results in difficulty in applying machine learning techniques where balanced labelled input data are required. In this paper, a Gaussian Mixture Model sampling method is proposed to tackle the problem of class imbalance for the memes sentiment classification task. To utilise both text and image data, a multi-modal CNN-LSTM model is proposed to jointly learn latent features for positive, negative and neutral category predictions. The experiments show that the re-sampling model can slightly improve the accuracy on the trial data of sub-task A of Task 8. The multi-modal CNN-LSTM model can achieve macro F1 score 0.329 on the test set

LinkLouvain: Link-Aware A/B Testing and Its Application on Online Marketing Campaign

A lot of online marketing campaigns aim to promote user interaction. The average treatment effect (ATE) of campaign strategies need to be monitored throughout the campaign. A/B testing is usually conducted for such needs, whereas the existence of user interaction can introduce interference to normal A/B testing. With the help of link prediction, we design a network A/B testing method LinkLouvain to minimize graph interference and it gives an accurate and sound estimate of the campaign's ATE. In this paper, we analyze the network A/B testing problem under a real-world online marketing campaign, describe our proposed LinkLouvain method, and evaluate it on real-world data. Our method achieves significant performance compared with others and is deployed in the online marketing campaign.Comment: Accepted by the Industrial & Practitioner Track of the 26th International Conference on Database Systems for Advanced Applications (DASFAA 2021

The Turbulent characteristic in the surface layer over dune at Naiman in Inner mongolia (Session 3: In-site Flux Observation studies)

In this paper, the turbulent and radiation data obtained over dune in Naiman from July 21 to Aug.10, 2000 have been analyzed. It has been discussed the relation between the non-dimensional turbulent variances and the stability z / L . The result shows that the changes of the non-dimensional velocity components, temperature and humidity variances with the stability in the surface layer under unstable stratification satisfy the Monin-Obukhov similarity theory. The energy budget in the surface layer over the movable dune has been studied also. The maximum sensible heat flux is 170 Wm−2 or so. The maximum soil heat flux in the surface layer is 100Wm−2 or so. The maximum net radiation flux is 400Wm−2 or so. The latent heat flux is always smaller than 60Wm−2 . The average ratio between (H + LE) and (R G) n − is 0.78 or so in the daytime during clear day. The energy imbalance has been found in the surface over the movable dune. The reason why the energy imbalance appears over heterogeneous surface needs to be studied more carefully in the next

Analysis of Astringent Components and Differential Gene Expression of Related Key Enzymes in Different Tissues of Fresh Lotus Seeds

This study was performed to explore the differences in the composition of astringent substances in different tissues of fresh lotus seeds and the expression of key enzyme genes involved in the synthesis of astringent compounds. The contents of soluble tannins, insoluble tannins and proanthocyanidins in lotus seed coat, lotus seed pulp without coat and lotus seed plumule were determined. Meanwhile, the activity and gene expression of key enzymes in the tannin synthesis pathway were detected. Sensory evaluation and electronic tongue analysis were performed on lotus seed samples. The data obtained was analyzed by orthogonal partial least squares discriminant analysis (OPLS-DA) and correlation analysis. Results showed that the major substance contributing to the astringency of lotus seeds was soluble tannins. Tannins had a positive effect on its excellent flavor at the waxy ripeness stage. Anthocyanin reductase was a key enzyme affecting the astringency intensity of lotus seeds. SnANR9 played a role in regulating the astringency of different tissues of lotus seeds