A thiol-functionalized magnetic mesoporous silica material (called SH-mSi@Fe
3O
4), synthesized by a modified Stöber method, has been investigated as a convenient and effective adsorbent for heavy ...metal ions. Structural characterization by powder X-ray diffraction, N
2 adsorption–desorption isotherm, Fourier transform infrared spectroscopy and elemental analyses confirms the mesoporous structure and the organic moiety content of this adsorbent. The high saturation magnetization (38.4
emu/g) make it easier and faster to be separated from water under a moderate magnetic field. Adsorption kinetics was elucidated by pseudo-second-order kinetic equation and exhibited 3-stage intraparticle diffusion mode. Adsorption isotherms of Hg and Pb fitted well with Langmuir model, exhibiting high adsorption capacity of 260 and 91.5
mg of metal/g of adsorbent, respectively. The distribution coefficients of the tested metal ions between SH-mSi@Fe
3O
4 and different natural water sources (groundwater, lake water, tap water and river water) were above the level of 10
5
mL/g. The material was very stable in different water matrices, even in strong acid and alkaline solutions. Metal-loaded SH-mSi@Fe
3O
4 was able to regenerate in acid solution under ultrasonication. This novel SH-mSi@Fe
3O
4 is suitable for repeated use in heavy metal removal from different water matrices.
Mercury pollution control has become a global goal. The accurate estimate of long-term mercury emissions in China is critical to evaluate the global mercury budget and the emission reduction ...potentials. In this study, we used a technology-based approach to compile a consistent series of China’s atmospheric mercury emissions at provincial level from 1978 to 2014. China totally emitted 13 294 t of anthropogenic mercury to air during 1978–2014, in which gaseous elemental mercury, gaseous oxidized mercury, and particulate-bound mercury accounted for 58.2%, 37.1%, and 4.7%, respectively. The mercury removed during this period were 2085 t in coal-fired power plants (counting 49% of mercury input), 7259 t in Zn smelting (79%), 771 t in coal-fired industrial boilers (25%), and 658 t in cement production plants (27%), respectively. Annual mercury emissions increased from 147 t in 1978 to 530 t in 2014. Both sectoral and spatial emissions of atmospheric mercury experienced significant changes. The largest mercury emission source evolved from coal-fired industrial boilers before 1998, to zinc smelting during 1999–2004, coal-fired power plants during 2005–2008, finally to cement production after 2009. Coal-fired industrial boilers and cement production have become critical hotpots for China’s mercury pollution control.
Abstract
In this paper, we present a spherical Fast Multipole Method (sFMM) for ray-tracing simulation of gravitational lensing on a curved sky. The sFMM is a nontrivial extension of the Fast ...Multiple Method to sphere
S
2
, and it can accurately solve the Poisson equation with time complexity of
O
(
N
)
log
(
N
)
, where
N
is the number of particles. It is found that the time complexity of the sFMM is near
O
(
N
) and the computational accuracy can reach 10
−10
in our test. In addition, compared with the Fast Spherical Harmonic Transform, the sFMM is not only faster but also more accurate, as it has the ability to reserve high-frequency components of the density field. These merits make the sFMM an optimum method to simulate the gravitational lensing on a curved sky, which is the case for upcoming large-area sky surveys, such as the Vera Rubin Observatory and the China Space Station Telescope.
Siberian ginseng, perennial herb belongs to Araliaceae family used in traditional medicines to treat hypertension, thrombus, inflammation and cancer. In the present study, we biosynthesized ...goldnanoparticles using Siberian ginseng aqeous extract in a cost effective manner. The synthesized Siberian ginseng gold nanoparticle (SG-GNPs) were characterized using UV-Vis spec, HR-TEM, XRD, FTIR, SAED analysis. UV-Vis spectroscopic analysis showed a surface Plasmon resonance peak at 538 nm which does not reduce till 30 days of incubation. The results of HR-TEM, XRD and SAED confirm the spherical shape, crystalline nature and the size of the synthesized gold nanoparticles. The FTIR results prove that the biological components present in the Siberian ginseng had reduced the gold ions to synthesis gold nanoparticles. After characterization, the efficacy of SG-GNPS against the melanoma, a deadliest skin carcinoma, was assessed in vitro using B16 murine melanoma cells. The CC50 dose of SG-GNPs against B16 cells were assessed with MTT assay and the anticancer activity was evaluated using Rhodamine 123, H2DCFDA and dual staining techniques. The induction of apoptosis by SG-GNPs against melanoma cells were confirmed with q-PCR analysis. The results of staining techniques prove that SG-GNPs increase the reactive oxygen species and decreased the mitochondrial membrane potential. It is further confirmed by the results of q-PCR analysis which shows increased apoptotic Bid, Bad, Casp3, Casp 9 genes and decreased antiapoptotic Bcl2 gene expression in SG-GNPs treated cells. Our results authentically prove the biosynthesized SG-GNPs induces apoptosis in melanoma cells and it possesses anticancer property.
Many applications, e.g., Uber, collect large-scale trajectory data from moving vehicles on road network. Trajectory data analytics can benefit many real-world applications, such as route planning and ...transportation optimizations. Two core operations in trajectory data analytics are trajectory similarity search and join, and both of them rely on a trajectory similarity function to measure the similarity between two trajectories. However, existing similarity functions focus on trajectory points distance and neglect the fact the trajectories should be on road network. Obviously aligning trajectories on road network can remove the noise points introduced by system errors. Toward this goal, we define a road-network-aware trajectory similarity function to measure trajectory similarity. To support trajectory similarity search and join, we propose a filtering-refine framework. In the filtering step, we compute a signature of each trajectory such that if two trajectories are similar, they must share a common signature. We utilize the signatures to prune a huge number of dissimilar pairs. In the refine step, we design effective algorithms to verify the candidates that are not pruned in the filtering step. To support large-scale trajectories, we develop a system DISON for Distributed In-Memory Trajectory Similarity Search and Join on Road Network. DISON splits trajectories into disjoint partitions by considering load balance and locality, and designs effective global index to prune irrelevant partitions. Extensive experiments on real datasets showed that our method achieved high effectiveness, efficiency, and scalability and outperformed existing solutions significantly.
Congenital long QT syndrome (LQTS) is a hereditary cardiac disorder characterized by QT-interval prolongation and T-wave abnormalities on electrocardiogram (ECG), and is associated with an increased ...risk of torsade de pointes and sudden cardiac death. Beta-blocker medication is effective in most patients except those with a very slow heart rate. Increased late sodium currents (INa-L) can result in bradycardia-dependent QT prolongation. Mexiletine, an inhibitor of INa-L, is not only effective in treating type-3 LQTS, but also shows the promise in managing LQTS patients of other genotypes with markedly prolonged QT interval at slow heart rates.
Ride-sharing (RS) has great values in saving energy and alleviating traffic pressure. Existing studies can be improved for better efficiency. Therefore, we propose a new ride-sharing model, where ...each driver has a requirement that if the driver shares a ride with a rider, the shared route percentage (i.e., the ratio of the shared route's distance to the driver's total travel distance) exceeds an expectation rate of the driver, e.g., 0.8. We consider two variants of this problem. The first considers multiple drivers and multiple riders and aims to compute driver-rider pairs to maximize the overall shared route percentage (SRP). We model this problem as the maximum weighted bigraph matching problem, where the vertices are drivers and riders, edges are driver-rider pairs, and edge weights are driver-rider's SRP. However, it is rather expensive to compute the SRP values for large numbers of driver-rider pairs on road networks. To address this problem, we propose an efficient method to prune many unnecessary driver-rider pairs and avoid computing the SRP values for every pair. To improve the efficiency, we propose an approximate method with error bound guarantee. The basic idea is that we compute an upper bound and a lower bound for each driver-rider pair in constant time. Then, we estimate an upper bound and a lower bound of the graph matching. Next, we select some driver-rider pairs, compute their real shortest-route distance, and update the lower and upper bounds of the maximum graph matching. We repeat above steps until the ratio of the upper bound to the lower bound is not larger than a given approximate rate. The second considers multiple drivers and a single rider and aims to find the top-<inline-formula><tex-math notation="LaTeX">k</tex-math> <inline-graphic xlink:href="li-ieq1-2760880.gif"/> </inline-formula> drivers for the rider with the largest SRP. We first prune a large number of drivers that cannot meet the SRP requirements. Then, we propose a best-first algorithm that progressively selects the drivers with high probability to be in the top-<inline-formula> <tex-math notation="LaTeX">k</tex-math> <inline-graphic xlink:href="li-ieq2-2760880.gif"/> </inline-formula> results and prunes the drivers that cannot be in the top-<inline-formula><tex-math notation="LaTeX"> k</tex-math> <inline-graphic xlink:href="li-ieq3-2760880.gif"/> </inline-formula> results. Extensive experiments on real-world datasets demonstrate the superiority of our method.
Reliable detection and quantification of antibiotic residues in food using surface-enhanced Raman spectroscopy remain challenging, since the intensities of SERS signals are vulnerable to matrix and ...experimental factors. In this work, a ratiometric SERS aptasensor using 6-Carboxyl-X-Rhodamine (ROX)-labeled aptamers and 4-mercaptobenzonitrile (4-MBN)-functionalized gold nanoparticles (Au NPs) as SERS probes was established for the reliable and rapid detection and quantification of enrofloxacin. In the presence of enrofloxacin, the conformational transform of aptamers took place, and the distance between ROX and Au NP increased, which resulted in a decrease in the SERS signal intensity of ROX. Meanwhile, the intensity of the SERS signal of 4-MBN was used as an internal standard. Reliable determination of enrofloxacin was realized using the ratio of the SERS signal intensities of ROX to 4-MBN. Under optimal conditions, the developed ratiometric SERS aptasensor provided a wide linear range from 5 nM to 1 µM, with a correlation coefficient (R
) of 0.98 and a limit of detection (LOD) of 0.12 nM (0.043 ppb). In addition, the developed ratiometric SERS aptasensor was successfully applied for the determination of enrofloxacin in fish and chicken meat, with recovery values of 93.6-112.0%. Therefore, the established ratiometric SERS aptasensor is sensitive, reliable, time-efficient, and has the potential to be applied in the on-site detection of enrofloxacin in complex matrices.
Mammalian genomes are viewed as functional organizations that orchestrate spatial and temporal gene regulation. CTCF, the most characterized insulator-binding protein, has been implicated as a key ...genome organizer. However, little is known about CTCF-associated higher-order chromatin structures at a global scale. Here we applied chromatin interaction analysis by paired-end tag (ChIA-PET) sequencing to elucidate the CTCF-chromatin interactome in pluripotent cells. From this analysis, we identified 1,480 cis- and 336 trans-interacting loci with high reproducibility and precision. Associating these chromatin interaction loci with their underlying epigenetic states, promoter activities, enhancer binding and nuclear lamina occupancy, we uncovered five distinct chromatin domains that suggest potential new models of CTCF function in chromatin organization and transcriptional control. Specifically, CTCF interactions demarcate chromatin-nuclear membrane attachments and influence proper gene expression through extensive cross-talk between promoters and regulatory elements. This highly complex nuclear organization offers insights toward the unifying principles that govern genome plasticity and function.
Metal-organic frameworks (MOFs) are supramolecular nanomaterials, in which metal ions or clusters are connected by organic ligands to form crystalline lattices with highly ordered periodic porous ...network structure. MOFs have been widely applied in various fields, such as catalyst, sample preparation, and sensing. In recent years, MOFs based surface enhanced Raman scattering (SERS) substrates have attracted much attention since MOFs can largely improve the performance of metallic SERS substrates toward target enrichment and signal enhancement. MOFs have been exploited in SERS analysis to tackle some challenges that bare metal substrates cannot achieve. Combination of MOFs and SERS improved the sensitivity of traditional SERS analysis and extended the application scope of SERS. With the increasing exploration of MOFs based SERS substrates, there is a great demand to review the advances in these researches. Herein, this review concentrated on summarizing the preparation and applications of MOFs based SERS substrates. Representative researches were discussed to better understand the property of MOFs based SERS substrates. The advantages of MOFs based SERS substrates were highlighted, as well as their limitations. In addition, the challenges, opportunities, and future trends in MOFs based SERS analysis were tentatively discussed.
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