Adsorption of 1-butyl-3-methylimidazolium chloride ionic liquid by functional carbon microspheres from hydrothermal carbonization of cellulose.

Functional carbonaceous material (FCM) loaded with carboxylic groups was prepared by hydrothermal carbonization of cellulose in the presence of acrylic acid. The resulting FCM was used as adsorbent for recovery of a water-soluble ionic liquid, 1-butyl-3-methyl-imidazolium chloride ([BMIM][Cl]). The FCM consisted of microspheres (100-150 nm) and had a low surface area (ca. 20 m(2)/g), but exhibited adsorption capacity comparable to that of commercial activated carbon which can be attributed to the presence of high content of polar oxygenated groups (-OH, -C═O, -COOH) as revealed by spectral analyses. Sorption of [BMIM][Cl] onto FCM adsorbent could be well-described by pseudo-second-order kinetics. Thermodynamic and adsorption isothermal analyses revealed that the adsorption process was spontaneous, exothermic, and could be described by the Freundlich adsorption model. The FCM adsorbent could be regenerated effectively and recycled for at least three times without loss of adsorption capacity. The results of this work provide a facile method for production of functional carbonaceous materials from renewable resources that can be used for treatment of aqueous streams containing small concentrations of ionic liquid, [BMIM][Cl].

Lightweight pyramid network with spatial attention mechanism for accurate retinal vessel segmentation.

PURPOSE: The morphological characteristics of retinal vessels are vital for the early diagnosis of pathological diseases such as diabetes and hypertension. However, the low contrast and complex morphology pose a challenge to automatic retinal vessel segmentation. To extract precise semantic features, more convolution and pooling operations are adopted, but some structural information is potentially ignored. METHODS: In the paper, we propose a novel lightweight pyramid network (LPN) fusing multi-scale features with spatial attention mechanism to preserve the structure information of retinal vessels. The pyramid hierarchy model is constructed to generate multi-scale representations, and its semantic features are strengthened with the introduction of the attention mechanism. The combination of multi-scale features contributes to its accurate prediction. RESULTS: The LPN is evaluated on benchmark datasets DRIVE, STARE and CHASE, and the results indicate its state-of-the-art performance (e.g., ACC of 97.09[Formula: see text]/97.49[Formula: see text]/97.48[Formula: see text], AUC of 98.79[Formula: see text]/99.01[Formula: see text]/98.91[Formula: see text] on the DRIVE, STARE and CHASE datasets, respectively). The robustness and generalization ability of the LPN are further proved in cross-training experiment. CONCLUSION: The visualization experiment reveals the semantic gap between various scales of the pyramid and verifies the effectiveness of the attention mechanism, which provide a potential basis for the pyramid hierarchy model in multi-scale vessel segmentation task. Furthermore, the number of model parameters is greatly reduced.

[Pollution Characteristics of Heavy Metals in PM2.5 Near Highway].

In this study, we evaluate the pollution characteristics of heavy metals in particulate matter with diameters less than 2.5 µm (PM2.5) near highways. Three rounds of cluster sampling of PM2.5 were conducted on three highways, Changzhang, Changtong, and Wenhou, in peri-urban areas near Nanchang from March to August 2018. The sampling sites included service areas, toll stations, tunnels, and areas near the highway. The concentrations of six heavy metals including Cu, Zn, Pb, Cd, Cr, and Ni in PM2.5 were analyzed using inductively coupled plasma mass spectrometry (ICP-MS). The pollution and distribution of heavy metals in PM2.5 near the highway were analyzed, and that pollution characteristics and the level of possible ecological jeopardy were assessed by using the Geoaccumulation Index and Potential Risk Index methods. No significant difference was observed in PM2.5 or in heavy metals in PM2.5 along highways with different traffic flow, but they differed significantly in among highway settings in the following order:super-long tunnels > long tunnels and area near the highway > service areas and toll stations. The heavy metal concentration in highways decreased in the following order:Zn (3.8 µg·m-3) > Pb (10.2×10-2 µg·m-3) > Cr (6.8×10-2 µg·m-3) > Cu (3.5×10-2 µg·m-3) > Ni (1.5×10-2 µg·m-3) > Cd (0.1×10-2 µg·m-3). In accordance with the influence of temperature and precipitation, PM2.5 and heavy metals in PM2.5 showed significant variations among the monitoring months. The PM2.5 concentration had a significant negative correlation with atmospheric temperature. We observed that PM2.5 concentration was significantly lower from May to August than from March to April. The Zn concentration in PM2.5 was more significant from May to August than from March to April. Pearson analysis showed a significant positive correlation between Zn in PM2.5 with atmospheric temperature because elevated temperatures could aggravate wear and tear and metallic corrosion, which then prompts the emission of Zn. According to the Geoaccumulation Index and Potential Ecological Jeopardy Index, the level of pollution associated with heavy metals of PM2.5 manifested in the following order:Zn and Cd > Pb > Cu > Ni and Cr. The pollution and degree of jeopardy associated with Zn and Cd were the most severe in the assessment criteria; therefore, the pollution by these elements and the sources of traffic should be noted in air pollution control plans. Super long tunnels, long tunnels, and areas near highways showed greater levels of pollution and higher potential ecological jeopardy than service areas and toll stations. The degree of pollution in densely populated service areas and toll stations was consistent across partially urban areas.

Viewpoint: Prevention is missing: is China's health reform reform for health?

Ancient China emphasized disease prevention. As a Chinese saying goes, 'it is more important to prevent the disease than to cure it'. Traditional Chinese medicine posits that diseases can be understood, thus, prevented. In today's China, the state of people's health seems worse than in the past. Thus the Chinese government undertook the creation of a new health system. Alas, we believe the results are not very satisfactory. The government seems to have overlooked rational allocation between resources for treatment and prevention. Public investment has been gradually limited to the domain of treatment. We respond to this trend, highlighting the importance of prevention and call for government and policymakers to adjust health policy and work out a solution suitable for improving the health of China's people.