Speed behaviour and mental workload of small-spacing expressway interchanges based on field driving test.

Many small-spacing interchanges (SSI) appear with the improvement of the expressway network. To investigate the speed and mental workload characteristics in the SSI and acquire the mechanism of the influence of speed on the drivers' workload, 37 participants were recruited to perform a field driving test. Each driver performed four driving conditions (i.e. ramp-mainline, mainline-ramp, mainline driving, and auxiliary lane driving). The speed and drivers' electrocardiogram (ECG) data were collected using SpeedBox speed acquisition equipment and PhysioLAB physiological instrument. The heart rate increase (HRI) index was used to analyse the drivers' mental workload regularity. The relationship model between speed and HRI was developed to examine the impact of speed on HRI. The results show that the speed variation in the SSI displayed two patterns: 'decrease - increase and continuous decrease.' The drivers' HRI variation presented four patterns: 'convex curve, continuously increasing, continuously decreasing and concave curve'. SSI's influenced area length is given based on the speed and HRI variation regularity. HRI is significantly higher when driving in the ramp-mainline condition in the SSI than when driving in other conditions, indicating that drivers are more nervous when merging with the mainline traffic. HRI increases significantly in the first 50% of the weaving area in four driving conditions, indicating that vehicle weaving greatly influences the drivers' mental workload. A positive correlation exists between vehicle speed and drivers' HRI without interference from other vehicles and road alignment.

The shorter spacing of the interchange will result in a more difficult driving task for the drivers. This study shows that drivers have the highest mental workload in ramp-mainline driving condition at small-spacing interchanges. The first half of the weaving area is the area where drivers' mental workload increases significantly, and is a high-risk section for small-spacing interchanges. This study can provide a reference for the revision of the allowable minimum interchange spacing in the corresponding specification, and the calibration of the simulation test parameters for similar scenarios.

Investigation of the Adsorption of Sulfamethoxazole by Degradable Microplastics Artificially Aged by Chemical Oxidation.

In this study, three different types of microplastics were aged by the thermal activation K2S2O8 method to investigate the adsorption behavior for sulfamethoxazole (SMX) in aqueous solution. The effects of pH, salinity and humic acid (HA) on adsorption behavior were also investigated. At the same time, the morphology and functional groups of microplastics before and after adsorption were characterized. As the aging time increased, the adsorption capacity of the microplastics also increased significantly. Whether it was pristine or aged, polylactic acid (PLA) had the highest adsorption capacity. The adsorption capacity of microplastics was the largest under acidic conditions, and its adsorption capacity decreased significantly in alkaline solutions. The presence of salinity inhibited the adsorption of SMX on polyethylene terephthalate (PET) and PP, but the adsorption capacity of PLA increases when salinity was above 10‰. The adsorption of SMX on microplastics was promoted by HA. When the concentration of HA was 20 mg/L, the adsorption capacity of PLA and PET decreased. Kinetic and isotherm fits were applied to the adsorption process. The increase in sorption capacity was related to the development of holes and cracks and the enhanced number of surface oxygen-containing functional groups. The adsorption kinetics to pristine microplastics conformed to a pseudo-first-order kinetic model, while the kinetics of the aged microplastics conformed to a pseudo-second-order kinetic model. It implies that the adsorption of SMX by aging microplastics involves multiple processes. The adsorption isothermal adsorption process of SMX by microplastics accorded with Freundlich model, belonging to multi-layer adsorption.

Enhanced bacterial quorum aggregation on a zeolite capping layer for sustainable inhibition of ammonium release from contaminated sediment.

The main objective of this study was to investigate how signal molecules enhance bacterial quorum aggregation on a zeolite capping layer for sustainable inhibition of ammonium release from contaminated sediment. Sediment remediation experiments were carried out by using nitrifying bacteria (WGX10, WGX18), denitrifying bacteria (HF3, HF7) and two kinds of signal molecules (OHHL, C8-HSL). The results showed that nitrifying bacteria and denitrifying bacteria could significantly aggregate on zeolite after adding 1.0 µM OHHL at a C/N ratio of 7. The maximum ammonium removal of five times the amount of ammonium adsorbed was achieved when 1.0 µM OHHL was added at the C/N ratio of 7 (the bio-regeneration rate was up to 88.32%), which was 1.24-2.02 times the ammonium removal amount at C/N ratios of 3, 5, 9. The concentration of total nitrogen in the overlying water was no more than 0.8 mg/L during four rounds of sediment remediation experiments. In addition, the bio-regeneration rate was up to 71.20%, which achieved sustainable inhibition of ammonium release from contaminated sediment.

Syntheses and effectiveness of functional peptide-based RAFT agents.

In this study, a series of functional peptide-based RAFT agents were designed and synthesized by the solid-phase supported peptide synthesis method. These novel RAFT agents have enabled chemists to make well-defined peptide-polymer conjugates with complicated topological structures. Additionally, our results have shown an unexpected reaction that takes place during these syntheses, and the conversion of a nitrile group to a carboxamide group has been evidently elucidated and unambiguously confirmed.

Effect of Fenton pre-oxidation on mobilization of nutrients and efficient subsequent bioremediation of crude oil-contaminated soil.

Fenton pre-oxidation and a subsequent bioremediation phase of 80 days were used to investigate the importance of matching concentration of residual indigenous bacteria and nutrient levels on subsequent bioremediation of crude oil. Experiments were performed using either high (>107.7 ± 0.2 CFU/g soil) or low (<105.9 ± 0.1 CFU/g soil) concentrations of bacteria and three different nutrient levels: enough (C/N > 9.8), moderate (C/N:5-9.8), and lacking nutrient level (C/N < 5) conditions. Weak Fenton pre-oxidation (225 mM H2O2 and 2.9 mM Fe2+) resulted in highly matching between nutrient level and the population of residual indigenous bacteria. Up to 53% of total petroleum hydrocarbon (TPH) and 58% of main hydrocarbon (C15C25, during the first 10 days) were removed from the soil. Under matching conditions, the activity of indigenous bacteria and nutrient mobilization were enhanced, promoting the bioremediation of crude oil. In addition, the biodegradation of long chain molecules (C26C30) required a high level of NH4+-N.

Impact of chemical oxidation on indigenous bacteria and mobilization of nutrients and subsequent bioremediation of crude oil-contaminated soil.

Fenton pre-oxidation provides nutrients to promote bioremediation. However, the effects of the indigenous bacteria that remain following Fenton oxidation on nutrient mobilization and subsequent bioremediation remain unclear. Experiments were performed with inoculation with native bacteria and foreign bacteria or without inoculation after four regimens of stepwise pre-oxidations. The effects of the indigenous bacteria remaining after stepwise oxidation on nutrient mobilization and subsequent bioremediation over 80 days were investigated. After stepwise Fenton pre-oxidation at a low H2O2 concentration (225×4), the remaining indigenous bacterial populations reached their peak (4.8±0.17×106CFU/g), the nutrients were mobilized rapidly, and the subsequent bioremediation of crude oil was improved (biodegradation efficiency of 35%). However, after stepwise Fenton pre-oxidation at a high H2O2 concentration (450×4), only 3.6±0.16×103CFU/g of indigenous bacteria remained, and the indigenous bacteria that degrade C15-C30 alkanes were inhibited. The nutrient mobilization was then highly limited, and only 19% of total petroleum hydrocarbon was degraded. Furthermore, the recovery period after the low H2O2 concentration stepwise Fenton pre-oxidation (225×4) was less than 20 days, which was 20-30 days shorter than with the other pre-oxidation treatments. Therefore, stepwise Fenton pre-oxidation at a low H2O2 concentration protects indigenous bacterial populations and improves the nutrient mobilization and subsequent bioremediation.

Aberrant whole-brain functional connectivity and intelligence structure in children with primary nocturnal enuresis.

AIM: To assess the potential relationship between intelligence structure abnormalities and whole-brain functional connectivity in children with primary nocturnal enuresis (PNE) with resting-state functional magnetic resonance imaging (fMRI) to provide insights into the association between these two seemingly unrelated conditions. METHODS: Intelligence testing and fMRI data were obtained from 133 right-handed children, including 67 PNE children (M/F, 39:28; age, 10.5 ± 1.2 y) and 66 age-matched healthy controls (M/F, 37:29; age, 10.1 ± 1.1 y). All intelligence tests were performed using the China-Wechsler Intelligence Scale for Children (C-WISC). Each subject's full intelligence quotient (FIQ), verbal IQ (VIQ), performance IQ (PIQ), and memory/caution (M/C) factor was measured and recorded. Resting state fMRI scans were performed on a 3.0-T MR scanner and post-processed using REST software. Comparisons of z-score correlation coefficients between distinct cerebral regions were used to identify altered functional connectivity in PNE children. RESULTS: The PNE group had normal FIQ, VIQ, and PIQ values, indicating no significant variation from the control group. However, the M/C factor was significantly lower in the PNE group. Compared to the control group, PNE children exhibited overall lower levels of functional connectivity that were most apparent in the cerebello-thalamo-frontal pathway. The M/C factor significantly correlated with z-scores representing connectivity between Cerebellum_Crus1_L and Frontal_Mid_R. CONCLUSION: PNE children exhibit intelligence structure imbalance and attention deficits. Our findings suggest that cerebello-thalamo-frontal circuit abnormalities are likely to be involved in the onset and progression of attention impairment in PNE children.

Assessment of memory/attention impairment in children with primary nocturnal enuresis: a voxel-based morphometry study.

AIM: Assessment of memory/attention impairment and related exploration of the gray matter differential MR density variations between children with and without primary nocturnal enuresis (PNE) using voxel-based morphometry (VBM) methodology is the aim of the present study. METHODS: A total of 75 right-handed PNE children (M/F=39:36, average age 10.4±1.3 years) and 72 age-matched, right-handed, healthy controls (M/F=40:32, 10.0 ± 1.2 years) were recruited for the study. First, intelligence tests were performed using the China-Wechsler Intelligence Scale for Children (C-WISC) in both PNE and control children. The full intelligence quotient (FIQ), verbal IQ (VIQ), performance IQ (PIQ), and memory/caution (M/C) factor were measured. Voxel-based morphometry (VBM) was performed using high resolution 3 Tesla T1-weighted MR images, processed using VBM5 in the PNE and control children. Student's t-test or Mann-Whitney U test were performed to analyze the difference in the gray matter density (GMD) between the PNE and control children. RESULTS: The FIQ, VIQ, and PIQ in the PNE group were within the normal range and did not significantly differ from the control group, though the M/C factor was statistically lower in the PNE group. Compared with normal controls, PNE children exhibited lower GMD in the right dorsolateral prefrontal cortex (DLPFC) and the left cerebellum (P<0.001). CONCLUSION: Impairment in memory/attention was detected in PNE children, and the structural abnormalities of the right DLPFC and left cerebellum are likely to be implicated in these deficits.