163 research outputs found
The Impact of D-amino acids on Formation and Integrity of Biofilm – Effect of Growth Condition and Bacteria Type
Biofouling is a major issue in applying nanofiltration and reverse osmosis technologies for wastewater treatment. Biofilm formed on the surface of membranes will severely decline the flux and cause energy waste. In this study, a novel biofouling control method that applies D-amino acids to inhibit biofilm formation was investigated. The D-amino acids previously reported to inhibit biofilm formation and disrupt existing biofilm – D-tyrosine and the mixture of D-tyrosine, D-tryptophan, D-leucine and D-methionine were tested. Pseudomonas aeruginosa and Bacillus subtilis were used as model Gram-negative and Gram-positive bacteria, respectively. D-amino acids have little effect and some effect on inhibition of biofilm formation and disruption of exiting biofilm to Pseudomonas aeruginosa, but have good effect to Bacillus subtilis. A commonly used microtiter plate assay for quantitative biofilm measurement was systematically evaluated and optimized for screening biofilm control agents. The effect of D-tyrosine on inhibition of organic fouling and P. aeruginosa biofouling on NF90 membrane surface in bench scale dead end filtration experiment was examined, which shows that D-tyrosine can effectively inhibit organic fouling and P. aeruginosa biofouling on NF90 membrane surface
Distributed Logistic Regression for Massive Data with Rare Events
Large-scale rare events data are commonly encountered in practice. To tackle
the massive rare events data, we propose a novel distributed estimation method
for logistic regression in a distributed system. For a distributed framework,
we face the following two challenges. The first challenge is how to distribute
the data. In this regard, two different distribution strategies (i.e., the
RANDOM strategy and the COPY strategy) are investigated. The second challenge
is how to select an appropriate type of objective function so that the best
asymptotic efficiency can be achieved. Then, the under-sampled (US) and inverse
probability weighted (IPW) types of objective functions are considered. Our
results suggest that the COPY strategy together with the IPW objective function
is the best solution for distributed logistic regression with rare events. The
finite sample performance of the distributed methods is demonstrated by
simulation studies and a real-world Sweden Traffic Sign dataset
Distributed Estimation and Inference for Spatial Autoregression Model with Large Scale Networks
The rapid growth of online network platforms generates large-scale network
data and it poses great challenges for statistical analysis using the spatial
autoregression (SAR) model. In this work, we develop a novel distributed
estimation and statistical inference framework for the SAR model on a
distributed system. We first propose a distributed network least squares
approximation (DNLSA) method. This enables us to obtain a one-step estimator by
taking a weighted average of local estimators on each worker. Afterwards, a
refined two-step estimation is designed to further reduce the estimation bias.
For statistical inference, we utilize a random projection method to reduce the
expensive communication cost. Theoretically, we show the consistency and
asymptotic normality of both the one-step and two-step estimators. In addition,
we provide theoretical guarantee of the distributed statistical inference
procedure. The theoretical findings and computational advantages are validated
by several numerical simulations implemented on the Spark system. Lastly, an
experiment on the Yelp dataset further illustrates the usefulness of the
proposed methodology
An Asymptotic Analysis of Minibatch-Based Momentum Methods for Linear Regression Models
Momentum methods have been shown to accelerate the convergence of the
standard gradient descent algorithm in practice and theory. In particular, the
minibatch-based gradient descent methods with momentum (MGDM) are widely used
to solve large-scale optimization problems with massive datasets. Despite the
success of the MGDM methods in practice, their theoretical properties are still
underexplored. To this end, we investigate the theoretical properties of MGDM
methods based on the linear regression models. We first study the numerical
convergence properties of the MGDM algorithm and further provide the
theoretically optimal tuning parameters specification to achieve faster
convergence rate. In addition, we explore the relationship between the
statistical properties of the resulting MGDM estimator and the tuning
parameters. Based on these theoretical findings, we give the conditions for the
resulting estimator to achieve the optimal statistical efficiency. Finally,
extensive numerical experiments are conducted to verify our theoretical
results.Comment: 45 pages, 5 figure
The Exploration and Evaluation of Generating Affective 360 Panoramic VR Environments Through Neural Style Transfer
Affective virtual reality (VR) environments with varying visual style can
impact users' valence and arousal responses. We applied Neural Style Transfer
(NST) to generate 360 VR environments that elicited users' varied
valence and arousal responses. From a user study with 30 participants, findings
suggested that generative VR environments changed participants' arousal
responses but not their valence levels. The generated visual features, e.g.,
textures and colors, also altered participants' affective perceptions. Our work
contributes novel insights about how users respond to generative VR
environments and provided a strategy for creating affective VR environments
without altering content
Novel solar forecasting scheme modelled by mixer dual path network and based on sky images
The prediction of global horizontal irradiance has become an effective technique to address the intermittence issue of photovoltaic (PV) power generation. This article proposes a novel deep neural network(DNN), named Mixer Dual Path Network (Mixer-DPN), for promising solar forecasting. It shares common features of cloud images and maintains the flexibility to explore new features through dual-path architecture by combining the Mixer layer and Dual Path Network. Therefore, the proposed model can provide more accurate prediction results compared to the classical DNN-based predictors. Moreover, the proposed model shows a faster convergence speed and smaller model size, which makes it suitable for a practical global horizontal irradiance. The merits of the proposed model are verified by testing it with the data from National Renewable Energy Laboratory comparing it with other DNN-based prediction models. Studies have shown that the new model has achieved excellent results in MSE, MAE and other indicators, and the R2 prediction accuracy rate has increased by 14% compared with the baseline model
Prediction of pediatric dose of tirzepatide from the reference adult dose using physiologically based pharmacokinetic modelling
Tirzepatide is an emerging hypoglycemic agent that has been increasing used in adults, yet its pharmacokinetic (PK) behavior and dosing regimen in pediatric population remain unclear. This study aimed to employ the physiologically based pharmacokinetic (PBPK) model to predict changes of tirzepatide exposure in pediatric population and to provide recommendations for its dose adjustments. A PBPK model of tirzepatide in adults was developed and verified by comparing the simulated plasma exposure with the observed data using PK-Sim&MoBi software. This model was then extrapolated to three specific age subgroups, i.e., children (10–12 years), early adolescents (12–15 years), and adolescents (15–18 years). Each subgroup included healthy and obese population, respectively. All known age-related physiological changes were incorporated into the pediatric model. To identify an appropriate dosing regimen that yielded PK parameters which were comparable to those in adults, the PK parameters for each aforementioned subgroup were predicted at pediatric doses corresponding to 87.5%, 75%, 62.5%, and 50% of the adult reference dose. According to the results of simulation, dose adjustments of tirzepatide are necessary for the individuals aged 10–12 years, as well as those aged 12–15 years with healthy body weights. In conclusion, the adult PBPK model of tirzepatide was successfully developed and validated for the first time, and the extrapolated pediatric model could be used to predict pediatric dosing regimen of tirzepatide, which will provide invaluable references for the design of future clinical trials and its rational use in the pediatric population
Lysine-specific demethylase 5C promotes hepatocellular carcinoma cell invasion through inhibition BMP7 expression
The primers used for the amplification of the indicated genes.(DOCX 17 kb
Differentiable Logic Machines
The integration of reasoning, learning, and decision-making is key to build
more general AI systems. As a step in this direction, we propose a novel
neural-logic architecture that can solve both inductive logic programming (ILP)
and deep reinforcement learning (RL) problems. Our architecture defines a
restricted but expressive continuous space of first-order logic programs by
assigning weights to predicates instead of rules. Therefore, it is fully
differentiable and can be efficiently trained with gradient descent. Besides,
in the deep RL setting with actor-critic algorithms, we propose a novel
efficient critic architecture. Compared to state-of-the-art methods on both ILP
and RL problems, our proposition achieves excellent performance, while being
able to provide a fully interpretable solution and scaling much better,
especially during the testing phase
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