An extended car-following model considering the influence of bus

Kako bi se opisalo ponašanje prometa kolone vozila, koja se sastoji od autobusa i osobnih automobila na autocesti, u ovom članku je predložen prošireni model kolone vozila za promet u jednoj traci. Predloženi model razlikuje četiri vrste kombinacija kolona automobil-autobus, automobil-nakon-autobusa, autobus-nakon-autobusa, autobus-nakon-automobila i automobil-nakon-automobila. Četiri kombinacije uzimaju u obzir udaljenost, brzinu i ubrzavanje/usporavanje kolone. Predložena metodologija je prikazana uporabom podataka prikupljenih kombinacijom mikrovalnog radarskog detektora i cestovnog laserskog detektora na aveniji Xuanwu u glavnom urbanom području Nanjinga. Osim toga, podaci o terenu podijeljeni su u dva seta podataka, jedan se koristi za uvježbavanje modela, a drugi je za ocjenu. Gazis model i Edie model, dva najčešće korištena modela kolone vozila, kalibrirani su prema istim skupovima podataka za vježbu, a koriste se kao referentna vrijednost. Konačno, izvedba modela, predložena ovim radom, uspoređena je s dva klasična modela na temelju evaluacijskih skupova podataka. Rezultati pokazuju da autobusi imaju različite karakteristike i manevriranost u usporedbi s osobnim automobilima. Uz utjecaj autobusa u procesu kolone vozila, to bi moglo dovesti do nejednake distribucije prometa na trakama i postati glavni razlog za smanjenje kapaciteta prometa autocesta. Model, predložen u ovom radu, precizniji je i stabilniji pri predviđanju ubrzanja/usporavanja različitih vozila tijekom kolone automobila. Nadmoćniji je za opis ponašanja kolone automobil pod utjecajem autobusa na autocesti.In order to describe car-following behaviour of traffic flow which is composed of buses and passenger cars on freeway, an extended car-following model is proposed for single lane traffic in this paper. The proposed model discriminates four types of car-bus following combination, car-following-bus, bus-following-bus, bus-following-car and car-following-car. The four combinations are considered in terms of following distance, following speed and following acceleration/deceleration. The proposed methodology is demonstrated using data collected from the combination of microwave radar detector and roadside laser detector on Xuanwu Avenue in the main urban area of Nanjing. Besides, the field data is divided into two data sets, one used for the training of the model, and the other for evaluation purpose. Gazis model and Edie model, the two most extensively used car-following models, are calibrated against the same training data sets and used as a reference benchmark. Finally, the performance of the model, proposed by this paper, was compared with the two classic models based on the evaluation data sets. The results show that buses have different characteristics and manoeuvrability compared with passenger cars. With the influence of buses in the car-following process, it could lead to uneven distribution of traffic flow on the lanes and become the main reason for traffic highway capacity decline. The model, proposed in this paper, is more accurate and stable when predicting acceleration/deceleration of different vehicles during car-following. It has better superiority to describe the car-following behaviours under the influence of bus on freeway

The GC Content as a Main Factor Shaping the Amino Acid Usage During Bacterial Evolution Process

Understanding how proteins evolve is important, and the order of amino acids being recruited into the genetic codons was found to be an important factor shaping the amino acid composition of proteins. The latest work about the last universal common ancestor (LUCA) makes it possible to determine the potential factors shaping amino acid compositions during evolution. Those LUCA genes/proteins from Methanococcus maripaludis S2, which is one of the possible LUCA, were investigated. The evolutionary rates of these genes positively correlate with GC contents with P-value significantly lower than 0.05 for 94% homologous genes. Linear regression results showed that compositions of amino acids coded by GC-rich codons positively contribute to the evolutionary rates, while these amino acids tend to be gained in GC-rich organisms according to our results. The first principal component correlates with the GC content very well. The ratios of amino acids of the LUCA proteins coded by GC rich codons positively correlate with the GC content of different bacteria genomes, while the ratios of amino acids coded by AT rich codons negatively correlate with the increase of GC content of genomes. Next, we found that the recruitment order does correlate with the amino acid compositions, but gain and loss in codons showed newly recruited amino acids are not significantly increased along with the evolution. Thus, we conclude that GC content is a primary factor shaping amino acid compositions. GC content shapes amino acid composition to trade off the cost of amino acids with bases, which could be caused by the energy efficiency

Secondary particle size determining sedimentation and adsorption kinetics of titanate-based materials for ammonia nitrogen and methylene blue removal

The effect of the main size distribution of particles on the adsorption process for adsorbent materials has been well-recognized; however, the impact of secondary particle size (agglomerated, aggregated or hydrated ones) on adsorbent properties and performance was rarely reported so far. In this study, a series of sodium titanates (STs) and peroxide modified sodium titanates (PSTs) with different primary particle sizes, and secondary sizes are synthesized by controlling synthesis conditions and subsequently applied to batch adsorption experiment. By employing scanning electron microscopes and Laser particle size analyzers, the particle sizes of STs and PSTs are found to be closely correlated with synthesis conditions. The surface morphology and specific surface area of titanates are size-dependent, while the components of all the samples maintained constant. The sedimentation experiment and CFD simulation demonstrated that particles with larger secondary sizes tended to settle more quickly than those with a bigger size. PSTs or STs particles with smaller secondary sizes could reach equilibrium more rapidly than those with the bigger size. The fitting results from Elovich and Weber-Morris models demonstrated that the particle sizes affect kinetics mainly through the liquid film diffusion process within the initial stages

ASFV pA151R negatively regulates type I IFN production via degrading E3 ligase TRAF6

African swine fever (ASF) caused by African swine fever virus (ASFV) is a highly mortal and hemorrhagic infectious disease in pigs. Previous studies have indicated that ASFV modulates interferon (IFN) production. In this study, we demonstrated that ASFV pA151R negatively regulated type I IFN production. Ectopic expression of pA151R dramatically inhibited K63-linked polyubiquitination and Ser172 phosphorylation of TANK-binding kinase 1 (TBK1). Mechanically, we demonstrated that E3 ligase TNF receptor–associated factor 6 (TRAF6) participated in the ubiquitination of TBK1 in cGAS-STING signaling pathway. We showed that pA151R interacted with TRAF6 and degraded it through apoptosis pathway, leading to the disruption of TBK1 and TRAF6 interaction. Moreover, we clarified that the amino acids H102, C109, C132, and C135 in pA151R were crucial for pA151R to inhibit type I interferon production. In addition, we verified that overexpression of pA151R facilitated DNA virus Herpes simplex virus 1 (HSV-1) replication by inhibiting IFN-β production. Importantly, knockdown of pA151R inhibited ASFV replication and enhanced IFN-β production in porcine alveolar macrophages (PAMs). Our findings will help understand how ASFV escapes host antiviral immune responses and develop effective ASFV vaccines

A Method for Generation Phage Cocktail with Great Therapeutic Potential

Background: Bacteriophage could be an alternative to conventional antibiotic therapy against multidrug-resistant bacteria. However, the emergence of resistant variants after phage treatment limited its therapeutic application. Methodology/Principal Findings: In this study, an approach, named ‘‘Step-by-Step’ ’ (SBS), has been established. This method takes advantage of the occurrence of phage-resistant bacteria variants and ensures that phages lytic for wild-type strain and its phage-resistant variants are selected. A phage cocktail lytic for Klebsiella pneumoniae was established by the SBS method. This phage cocktail consisted of three phages (GH-K1, GH-K2 and GH-K3) which have different but overlapping host strains. Several phage-resistant variants of Klebsiella pneumoniae were isolated after different phages treatments. The virulence of these variants was much weaker [minimal lethal doses (MLD).1.3610 9 cfu/mouse] than that of wild-type K7 countpart (MLD = 2.5610 3 cfu/mouse). Compared with any single phage, the phage cocktail significantly reduced the mutation frequency of Klebsiella pneumoniae and effectively rescued Klebsiella pneumoniae bacteremia in a murine K7 strain challenge model. The minimal protective dose (MPD) of the phage cocktail which was sufficient to protect bacteremic mice from lethal K7 infection was only 3.0610 4 pfu, significantly smaller (p,0.01) than that of single monophage. Moreover, a delayed administration of this phage cocktail was still effective in protection against K7 challenge. Conclusions/Significance: Our data showed that the phage cocktail was more effective in reducing bacterial mutatio

Three Capsular Polysaccharide Synthesis-Related Glucosyltransferases, GT-1, GT-2 and WcaJ, Are Associated With Virulence and Phage Sensitivity of Klebsiella pneumoniae

Klebsiella pneumoniae (K. pneumoniae) spp. are important nosocomial and community-acquired opportunistic pathogens, which cause various infections. We observed that K. pneumoniae strain K7 abruptly mutates to rough-type phage-resistant phenotype upon treatment with phage GH-K3. In the present study, the rough-type phage-resistant mutant named K7RR showed much lower virulence than K7. Liquid chromatography-tandem mass spectrometry (LC-MS-MS) analysis indicated that WcaJ and two undefined glycosyltransferases (GTs)- named GT-1, GT-2- were found to be down-regulated drastically in K7RR as compared to K7 strain. GT-1, GT-2, and wcaJ are all located in the gene cluster of capsular polysaccharide (CPS). Upon deletion, even of single component, of GT-1, GT-2, and wcaJ resulted clearly in significant decline of CPS synthesis with concomitant development of GH-K3 resistance and decline of virulence of K. pneumoniae, indicating that all these three GTs are more likely involved in maintenance of phage sensitivity and bacterial virulence. Additionally, K7RR and GT-deficient strains were found sensitive to endocytosis of macrophages. Mitogen-activated protein kinase (MAPK) signaling pathway of macrophages was significantly activated by K7RR and GT-deficient strains comparing with that of K7. Interestingly, in the presence of macromolecular CPS residues (>250 KD), K7(ΔGT-1) and K7(ΔwcaJ) could still be bounded by GH-K3, though with a modest adsorption efficiency, and showed minor virulence, suggesting that the CPS residues accumulated upon deletion of GT-1 or wcaJ did retain phage binding sites as well maintain mild virulence. In brief, our study defines, for the first time, the potential roles of GT-1, GT-2, and WcaJ in K. pneumoniae in bacterial virulence and generation of rough-type mutation under the pressure of bacteriophage