TrajStat: GIS-based software that uses various trajectory statistical analysis methods to identify potential sources from long-term air pollution measurement data

Statistical analysis of air mass back trajectories combined with long-term ambient air pollution measurements are useful tools for source identification. Using these methods, the geographic information system (GIS) based software, TrajStat, was developed to view, query, and cluster the trajectories and compute the potential source contribution function (PSCF) and concentration weighted trajectory (CWT) analyses when measurement data are included.     

Templated electrodeposition of Ag7NO11 nanowires with very high oxidation states of silver

The templated electrodeposition of 200 nm diameter nanowires of the argentic oxynitrate Ag(Ag₃O₄)₂NO₃ phase is reported. Their high surface-to-volume ratio and the high average oxidation state of Ag make these wires promising candidates for nanoscale redox processes in which both a high volumetric charge density and a high discharge rate are required. The antibiotic activity of these nanowires was demonstrated by inhibiting the growth of Bacillus cereus bacteria.     

The effect of micro-grinding and micro-graphite flotation to upgrade the quality of calcite concentrate,with reference to Kurikka calcite marble deposit,Finland

High purity of calcium carbonate deposits are rare. Even the purest calcite marbles contain accessory minerals, which may degrade the deposit in terms of its suitability for paper pigment application. Most of these impurities could be removed by traditional calcite–silicate flotation to produce quality ground calcium carbonate. However, micro-graphite enclosed by calcite remains un-liberated with the traditional flotation particle size distribution. Further grinding alone simply exposes such graphite on the surface of calcite and reduces the brightness of the concentrate.In Kurikka calcite marble, micro-graphite particles of varying morphology occur along calcite grain boundaries and other crystallographic discontinuities. Due to such submicroscopic graphite particles, the calcite concentrate produced from the Kurikka calcite marble by calcite–silicate flotation gives an average ISO brightness value of 83.7.This study shows the application of micro-grinding followed by micro-graphite flotation to remove such fine-grained graphite. As a result, the quality of the calcite concentrate was upgraded to an average brightness value of 92.3.     

Reproducible and Sensitive Plasmonic Sensing Platforms Based on Au-Nanoparticle-Internalized Nanodimpled Substrates

Electromagnetic enhancement effects through localized surface plasmon resonance considerably amplify the intensity of incident light when molecules are positioned in the vicinity of miniscule nanogaps. The aggregation of plasmonic nanoparticles synthesized using bottom-up methods has been extensively used to generate hot spots in solutions. These methods assist in obtaining non-periodic plasmonic signals, because the realization of uniform nanogaps through particle aggregation is difficult. Nanostructured substrates with gaps of 20–100 nm have also been fabricated using the top-down approach. However, the fabrication of smaller nanogap templates using these methods is difficult owing to high costs and low throughput. Therefore, a nanodimple array internalized with AuNPs is developed in this study to mitigate the challenges encountered in the bottom-up and top-down approaches. Precise nanogaps are generated by regularly internalizing AuNPs in the cavities of nanodimples through DNA hybridization. Simulations of the electric field distribution indicate that the incorporation of 80 nm-sized AuNPs into a curved nanodimpled Au substrate generate high-density volumetric hot spots within a detection volume, and result in a high plasmonic enhancement factor of 8.25 × 10⁷. The tremendous potential of the proposed plasmonic platform as an SERS-based biomedical diagnostic device is also verified.     

Graphene quantum dots in alveolar macrophage: uptake-exocytosis,accumulation in nuclei,nuclear responses and DNA cleavage

Background

Given the tremendous potential for graphene quantum dots (QDs) in biomedical applications, a thorough understanding of the interaction of these materials with macrophages is essential because macrophages are one of the most important barriers against exogenous particles. Although the cytotoxicity and cellular uptake of graphene QDs were reported in previous studies, the interaction between nuclei and the internalized graphene QDs is not well understood. We thus systematically studied the nuclear uptake and related nuclear response associated with aminated graphene QDs (AG-QDs) exposure.

Results

AG-QDs showed modest 24-h inhibition to rat alveolar macrophages (NR8383), with a minimum inhibitory concentration (MIC) of 200 μg/mL. Early apoptosis was significantly increased by AG-QDs (100 and 200 μg/mL) exposure and played a major role in cell death. The internalization of AG-QDs was mainly via energy-dependent endocytosis, phagocytosis and caveolae-mediated endocytosis. After a 48-h clearance period, more than half of the internalized AG-QDs remained in the cellular cytoplasm and nucleus. Moreover, AG-QDs were effectively accumulated in nucleus and were likely regulated by two nuclear pore complexes genes (Kapβ2 and Nup98). AG-QDs were shown to alter the morphology, area, viability and nuclear components of exposed cells. Significant cleavage and cross-linking of DNA chains after AG-QDs exposure were confirmed by atomic force microscopy investigation. Molecular docking simulations showed that H-bonding and π-π stacking were the dominant forces mediating the interactions between AG-QDs and DNA, and were the important mechanisms resulting in DNA chain cleavage. In addition, the generation of reactive oxygen species (ROS) (e.g., ?OH), and the up-regulation of caspase genes also contributed to DNA cleavage.

Conclusions

AG-QDs were internalized by macrophages and accumulated in nuclei, which further resulted in nuclear damage and DNA cleavage. It is demonstrated that oxidative damage, direct contact via H-bonding and π-π stacking, and the up-regulation of caspase genes are the primary mechanisms for the observed DNA cleavage by AG-QDs.

     

短链脂肪酸改善2型糖尿病小鼠胰岛素抵抗和胰腺损伤

以链脲佐菌素(Streptozotocin,STZ)诱导的糖尿病小鼠为研究对象,研究短链脂肪酸对糖尿病小鼠血糖代谢的改善作用。通过腹腔注射200 mg/kg STZ建立糖尿病小鼠模型,研究乙酸钠、丙酸钠和丁酸钠对糖尿病小鼠进食量和体重变化、口服葡萄糖耐量(OGTT)、血糖水平、血清胰岛素水平、胰岛素抵抗(HOMA-IR)、胰岛β细胞功能(HOMA-β)指数及胰腺组织结构的影响。结果显示:与模型组相比,乙酸钠和丙酸钠可显著降低累计进食量(p0.05),分别降低了10.09%和8.90%;乙酸钠和丁酸钠,对2型糖尿病小鼠其他指标包括体重、空腹血糖、葡萄糖耐量、胰岛素抵抗和胰腺组织损伤修复都没有显著改善作用(p0.05)。丙酸钠可以显著降低血糖水平(20.65%)和胰岛素抵抗(11.19%),增强胰岛β细胞功能(64.50%),提高葡萄糖耐量,对胰腺组织损伤起到改善作用。     

Classification of edible oils using synchronous scanning fluorescence spectroscopy

Total luminescence and synchronous scanning fluorescence spectroscopy techniques were tested as regards their ability to characterize and differentiate edible oils, including soybean, sunflower, rapeseed, peanut, olive, grapeseed, linseed and corn oils. Total luminescence spectra of all oils studied as n-hexane solutions exhibit an intense peak, which appears at 290 nm in excitation and 320 nm in emission, attributed to tocopherols. Some of the oils exhibit a second long-wavelength peak, appearing at 405 nm in excitation and 670 nm in emission, belonging to pigments of the chlorophyll group. Additional bands were present in the intermediate range of excitation and emission wavelengths in some oils, arising from unidentified compounds. Similarly, bands attributed to tocopherols, chlorophylls and unidentified fluorescent components were detected in the synchronous-scanning fluorescence spectra. Classification of oils based on their synchronous fluorescence spectra was performed using a non-parametrical k nearest neighbours method and linear discriminant analysis. Both methods provided very good discrimination between the oil classes with low classification error. The results presented demonstrate the capability of the fluorescence techniques for characterizing and differentiating vegetable oils.     

Energy systems planning and GHG-emission control under uncertainty in the province of Liaoning,China – A dynamic inexact energy systems optimization model

In this study, a dynamic interval-parameter optimization model (DIP-REM) has been developed for supporting long-term energy systems planning in association with GHG mitigation in the region of Liaoning province. The model can describe Liaoning province energy planning systems as networks of a series of energy flows, transferring extracted/imported energy resources to end users through a variety of conversion and transmission technologies over a number of periods and address the problem of GHG-emission reduction within a general energy planning systems framework under uncertainty. Two scenarios (including a reference case) are considered corresponding to different GHG-emission mitigation levels for in-depth analysis of interactions existing among energy, socio-economy and environment in the Liaoning province. Useful solutions for Liaoning province energy planning systems have been generated, reflecting trade-offs among energy-related, environmental and economic considerations. The results can not only provide optimal energy resource/service allocation and capacity-expansion plans, but also help decision-makers identify desired policies for GHG mitigation with a cost-effective manner in the region of Liaoning province. Thus, it can be used by decision makers as an effective technique in examining and visualizing impacts of energy and environmental policies, regional development strategies and emission reduction measures within an integrated and dynamic framework.     

3-D Multi-scale air pollution modelling using adaptive unstructured meshes

High resolution models of air pollution transport and transformation are necessary in order to test possible abatement strategies based on pollution control and to forecast high pollution episodes. Models are especially relevant for secondary pollutants like ozone and nitrogen dioxide which are formed in the atmosphere through nonlinear chemical reactions involving primary pollutant species far from their sources. Often we are trying to resolve the interactions between plumes from point sources such as power stations and regional pollution tides of ozone formed in other European countries. One method of tackling this problem of different scales is with different grid sizes, using highly resolved grids in regions where the structure is very fine. This paper describes the use of 3-D adaptive gridding models for pollution transport and reaction using both a layered and a fully adaptive 3-D tetrahedral approach.