Chemical Control and Understanding of Horizontal Gene Transfers, Drug-Resistance Development, and Filament and Biofilm Formation

Biofilms formed by microbes on surfaces are the sources for persistent infectious diseases and environmental problems. The mechanism and details of how antibiotics promote biofilm formation is largely unknown. For instance, it not clear what stages of biofilm growth are promoted to proceed faster than without antibiotics, what phenotypes of bacteria form in an antibiotic-promoted biofilm, and what different biofilm compositions and structures are caused by the presence of antibiotics. Among other effects, antibiotics can cause bacteria to form filaments of living bacteria. Here, we conduct a real-time study of the adherence of bacteria and antibiotic-induced filamentous bacteria on surfaces and characterize the kinetics of surface adherence of these two forms of bacteria. Studying the effect of different surfaces on promoting filamentous bacteria’s adherence on surfaces, we characterize an unexpected correlation between the stage of bacterial growth and the formation and growth of filamentous bacteria on surfaces. Based on these results, we outline the lifestyle of filamentous bacteria and a mechanism by which antibiotics promote biofilm formation. The drug resistance of bacteria is becoming more severe since antibiotics are first discovered. The development of drug-resistance among bacteria involves spreading and drug-resistant gene “horizontally” between bacteria. These horizontal gene transfers impact the gene composition and evolution of the bacteria, and facilitate the transfer of antibiotic resistance genes. At the molecular level, all three major mechanisms of HGTs, transformation, conjugation and transduction, involve type IV pili appendages on bacterial surfaces. Here, the three mechanisms of horizontal gene transfer are studied. Saturated farnesol derivatives show inhibition effect on tetracycline-enhanced plasmid transformation, ciprofloxacin-enhances PAPI-1 transduction, and PAPI-1 conjugation. Further study of ciprofloxacin-resistance development in P. aeruginosa is conducted by using serial passage assay. The inhibited development of MIC of ciprofloxacin suggest that saturated farnesol derivative inhibits the development of resistance to ciprofloxacin in P. aeruginosa. This thesis also describes the mechanism of pili inhibition by saturated farnesol derivatives. The pili-mediated bacteriophage adsorption is studied, and the results demonstrate that saturated farnesol derivative could cause pili retraction, leading to inhibition of bacteriophage adsorption. More evidence was obtained from other colleagues in Dr. Luk’s lab to support the small molecules binding to pili. The MALDI-MS done by Hewen Zheng suggests that saturated farnesol derivative covalently binds to pili. Hewen also performed the alkaline buffer extraction experiment to demonstrate that PAO1 culturing with saturated farnesol derivative resulted in decrease in pili protein expression. Together with the bacteriophage adsorption results, we conclude that saturated farnesol derivative binding to pili cause pili retraction

Understand Legal Documents with Contextualized Large Language Models

The growth of pending legal cases in populous countries, such as India, has become a major issue. Developing effective techniques to process and understand legal documents is extremely useful in resolving this problem. In this paper, we present our systems for SemEval-2023 Task 6: understanding legal texts (Modi et al., 2023). Specifically, we first develop the Legal-BERT-HSLN model that considers the comprehensive context information in both intra- and inter-sentence levels to predict rhetorical roles (subtask A) and then train a Legal-LUKE model, which is legal-contextualized and entity-aware, to recognize legal entities (subtask B). Our evaluations demonstrate that our designed models are more accurate than baselines, e.g., with an up to 15.0% better F1 score in subtask B. We achieved notable performance in the task leaderboard, e.g., 0.834 micro F1 score, and ranked No.5 out of 27 teams in subtask A.Comment: SemEval 202

Frost Growth Detection Using Capacitive Sensor

Frost buildup on surfaces could be an undesired situation in many applications. In refrigeration and heat pump system, typically, frost grows on the fin surface of the heat exchanger due to different environmental/operational conditions. On one hand, it can block the air flow and increase air-side pressure drop; on the other hand, can increase the thermal resistance and deteriorate heat transfer performance. As a result, frost buildup can significantly reduce the system’s COP. Therefore, most systems encountered frost buildup run the defrost cycle. The frost growth process is affected by many factors, such as environmental conditions (air humidity, temperature, flow rate), operational conditions (working fluids, saturated temperature), heat exchangers (structures, fin type and fin surface wettability) et. al.. All those factors are coupled together, which makes frost growth a very complex dynamic process with variable spatial distribution of its characteristic parameters. It is very important to dynamically detect frost growth for both effective defrost control and precise frost modelling. In this work, a capacitive sensor for frost detection has been developed, which consists of three parts as shown in Figure 1(a): 1) commercial capacitive to digital converter (FDC2214 from Texas Instruments and the resolution of the reading is 0.0001pF), 2) PCB connector and 3) fabricated electrodes. The fabricated copper electrode is attached to the PCB connector, which is mounted to the capacitive to digital converter and connected to the computer by a USB interface. Capacitance variation can be measured when the target properties changes. The interdigital electrodes has a high sensitivity and were fabricated by lithophotography, using copper laminates/ deposited copper thin layer as shown in Figure 1(b) The sensitivity can be affected by metallization ratios, width and thickness of the insulation layer, which are also explored in this work. The frost grows on a cold plate which is placed in the wind tunnel with a controlled air temperature, humidity and flow rate. The electrode of the capacitive sensor is located beside the side wall of the cold plate, as shown in Figure 1(c). The frost growth process can be detected and reflected by the capacitance variation of the sensor, as shown in Figure 2, the capacitance variation can reflect different stage of the frost growth period, starting from condensation to mature growth. Images are also captured by a CCD camera to calibrate the signal. This work demonstrates the dynamic frost growth detection at the first time and could play a significant role to understanding frost growth mechanism and defrost control strategy

Initial data gluing in the asymptotically flat regime via solution operators with prescribed support properties

We give new proofs of general relativistic initial data gluing results on unit-scale annuli based on explicit solution operators for the linearized constraint equation around the flat case with prescribed support properties. These results retrieve and optimize - in terms of positivity, regularity, size and/or spatial decay requirements - a number of known theorems concerning asymptotically flat initial data, including Kerr exterior gluing by Corvino-Schoen and Chru\'sciel-Delay, interior gluing (or "fill-in") by Bieri-Chru\'sciel, and obstruction-free gluing by Czimek-Rodnianski. In particular, our proof of the strengthened obstruction-free gluing theorem relies on purely spacelike techniques, rather than null gluing as in the original approach.Comment: 30 pages, 1 figure. Comments are welcome

Can customer loyalty created by online brand experience affect physical product sales?

The brand experience has been a focus of research in the marketing field since it was introduced. Numerous studies have previously demonstrated that brand experience has a positive impact on customer loyalty. In addition, brand experience has also been shown to be a multi-dimensional construct, with each dimension having a different degree of impact on customer loyalty. Nowadays, with the popularity of the internet, it is becoming more and more common to offer brand experiences to customers in an online environment. In this new era, a category of virtual brands has emerged that offer customers an online brand experience solely through their app or website. Previous research on brand experience and customer loyalty has mainly focused on offline brand experiences. This study pays attention to the online health brands in China, with the aim of examining whether virtual brands can still have a positive impact on customer loyalty despite the online only brand experience they provide. Furthermore, once some online health brands have gained a stable user base through their apps or websites, they have begun to expand their marketing and develop related offline products through brand extension. Previous research has demonstrated that both brand experience and customer loyalty have a positive effect on brand extension. However, as the virtual brands are a type of brand that has emerged since the popularity of the internet, there is little research on the development of offline extensions for virtual brands. The second objective of this study is to fill this research gap by examining whether customer loyalty, influenced by the online brand experience, has a positive effect on the sale of these products when these online brands extend their brands offline to launch physical products. This study has adopted a quantitative approach, and "KEEP", a representative online health brand in China, has been selected as the subject of the empirical study. The data has been collected by distributing an online questionnaire to users of the KEEP app through the Chinese questionnaire distribution platform "WENJUANXING", and the 210 questionnaires collected have been then analysed by SPSS. The results of the multiple regression analysis show that online brand experience still has a positive effect on customer loyalty and that different dimensions of online brand experience do have different degrees of influence on customer loyalty. However, due to the different research contexts, the impact of each dimension on online brand experience differs significantly from previous research. In this context, emotional experience and usability experience has been found to have the greatest impact on customer loyalty, followed by cognitive experience. The loyalty of customers to virtual brands is rarely influenced by social experience. The sensory experience and behavioural experience offered by online health brands through apps have no impact on customer loyalty. Furthermore, the results of the univariate regression analysis demonstrate that user loyalty to online health brands has a positive impact on the sale of offline brand extensions offered by these brands. This study fills a gap in research on the relationship between brand experience, customer loyalty and brand extensions for online health brands. The results have implications for the design of online brand experiences and the launch of offline brand extensions for online health brands and even for all virtual brands in China

Experimental Study of Condensation Heat Transfer of R134a on Oil-infusion Surfaces

Dropwise condensation, since first recognized in 1930, has stimulated interest because its heat transfer coefficient (HTC) is much higher than film condensation. For some applications, not only a higher heat transfer performance is desired, but also the retention of the fluids on the surface can be a big issue. For example, the refrigerant retention in some enhanced tube can block the contact of the vapor-solid interface and increase the thermal resistance; it also can increase the charge of refrigerant because certain amount of refrigerant could not go through the system cycle. Many efforts were dedicated to modifying the surface and promote dropwise condensation, and most research focus on the condensation of water vapor. It is very challenging to promote dropwise condensation for working fluids with a lower surface tension than water, such as refrigerant. Research have been conducted on dropwise condensation for low surface tension fluids using oil-infusion surface, which is promoted by the contact of drop to the liquid-vapor interface instead of solid-vapor interface. However, the effectiveness and efficiency of the oil-infusion surface is still a critical challenge, and the heat transfer mechanism of dropwise condensation with such liquid-liquid interface stays unclear. In this work, condensation of R134a on oil-immerged surfaces is investigated. Heat transfer coefficient is measured, and formation of the condensate is observed using a high speed camera. Two cavity surfaces of different porous scale are examined, of which, one is nanoscale pores and another is microscale pores Mineral oil of low miscibility to R134a is soaked to be saturated in the cavity prior to the experiment. All experiments were conducted under saturated condition of ambient temperature (around 22 °C) in a pressure chamber. The subcool level of the condensation is 10 °C. Images of the local condensation formation is analyzed and heat transfer coefficient is also compared for different surfaces. The duration of the oil-infusion surface is also tested for both surfaces

Antiviral activity of interleukin-11 as a response to porcine epidemic diarrhea virus infection

International audienceAbstractInterleukin-11 (IL-11), a well-known anti-inflammatory factor, provides protection from intestinal epithelium damage caused by physical or chemical factors. However, little is known of the role of IL-11 during viral infections. In this study, IL-11 expression at mRNA and protein levels were found to be high in Vero cells and the jejunum of piglets during porcine epidemic diarrhea virus (PEDV) infection, while IL-11 expression was found to be positively correlated with the level of viral infection. Pretreatment with recombinant porcine IL-11 (pIL-11) was found to suppress PEDV replication in Vero E6 cells, while IL-11 knockdown promoted viral infection. Furthermore, pIL-11 was found to inhibit viral infection by preventing PEDV-mediated apoptosis of cells by activating the IL-11/STAT3 signaling pathway. Conversely, application of a STAT3 phosphorylation inhibitor significantly antagonized the anti-apoptosis function of pIL-11 and counteracted its inhibition of PEDV. Our data suggest that IL-11 is a newfound PEDV-inducible cytokine, and its production enhances the anti-apoptosis ability of epithelial cells against PEDV infection. The potential of IL-11 to be used as a novel therapeutic against devastating viral diarrhea in piglets deserves more attention and study

pTSE: A Multi-model Ensemble Method for Probabilistic Time Series Forecasting

Various probabilistic time series forecasting models have sprung up and shown remarkably good performance. However, the choice of model highly relies on the characteristics of the input time series and the fixed distribution that the model is based on. Due to the fact that the probability distributions cannot be averaged over different models straightforwardly, the current time series model ensemble methods cannot be directly applied to improve the robustness and accuracy of forecasting. To address this issue, we propose pTSE, a multi-model distribution ensemble method for probabilistic forecasting based on Hidden Markov Model (HMM). pTSE only takes off-the-shelf outputs from member models without requiring further information about each model. Besides, we provide a complete theoretical analysis of pTSE to prove that the empirical distribution of time series subject to an HMM will converge to the stationary distribution almost surely. Experiments on benchmarks show the superiority of pTSE overall member models and competitive ensemble methods.Comment: The 32nd International Joint Conference on Artificial Intelligence (IJCAI 2023