SEEI: spherical evolution with feedback mechanism for identifying epistatic interactions.

BACKGROUND: Detecting epistatic interactions (EIs) involves the exploration of associations among single nucleotide polymorphisms (SNPs) and complex diseases, which is an important task in genome-wide association studies. The EI detection problem is dependent on epistasis models and corresponding optimization methods. Although various models and methods have been proposed to detect EIs, identifying EIs efficiently and accurately is still a challenge. RESULTS: Here, we propose a linear mixed statistical epistasis model (LMSE) and a spherical evolution approach with a feedback mechanism (named SEEI). The LMSE model expands the existing single epistasis models such as LR-Score, K2-Score, Mutual information, and Gini index. The SEEI includes an adaptive spherical search strategy and population updating strategy, which ensures that the algorithm is not easily trapped in local optima. We analyzed the performances of 8 random disease models, 12 disease models with marginal effects, 30 disease models without marginal effects, and 10 high-order disease models. The 60 simulated disease models and a real breast cancer dataset were used to evaluate eight algorithms (SEEI, EACO, EpiACO, FDHEIW, MP-HS-DHSI, NHSA-DHSC, SNPHarvester, CSE). Three evaluation criteria (pow1, pow2, pow3), a T-test, and a Friedman test were used to compare the performances of these algorithms. The results show that the SEEI algorithm (order 1, averages ranks = 13.125) outperformed the other algorithms in detecting EIs. CONCLUSIONS: Here, we propose an LMSE model and an evolutionary computing method (SEEI) to solve the optimization problem of the LMSE model. The proposed method performed better than the other seven algorithms tested in its ability to identify EIs in genome-wide association datasets. We identified new SNP-SNP combinations in the real breast cancer dataset and verified the results. Our findings provide new insights for the diagnosis and treatment of breast cancer. AVAILABILITY AND IMPLEMENTATION: https://github.com/scutdy/SSO/blob/master/SEEI.zip .

Integrated analysis of the DNA methylome and RNA transcriptome during the development of skeletal muscle in Duroc pigs.

BACKGROUND: Skeletal muscle development plays a crucial role in yield and quality of pork; however, this process is influenced by various factors. In this study, we employed whole-genome bisulfite sequencing (WGBS) and transcriptome sequencing to comprehensively investigate the longissimus dorsi muscle (LDM), aiming to identify key genes that impact the growth and development of Duroc pigs with different average daily gains (ADGs). RESULTS: Eight pigs were selected and divided into two groups based on ADGs: H (774.89 g) group and L (658.77 g) group. Each pair of the H and L groups were half-siblings. The results of methylation sequencing revealed 2631 differentially methylated genes (DMGs) involved in metabolic processes, signalling, insulin secretion, and other biological activities. Furthermore, a joint analysis was conducted on these DMGs and the differentially expressed genes (DEGs) obtained from transcriptome sequencing of the same individual. This analysis identified 316 differentially methylated and differentially expressed genes (DMEGs), including 18 DMEGs in promoter regions and 294 DMEGs in gene body regions. Finally, LPAR1 and MEF2C were selected as candidate genes associated with muscle development. Bisulfite sequencing PCR (BSP) and quantitative real-time PCR (qRT-PCR) revealed that the promoter region of LPAR1 exhibited significantly lower methylation levels (P < 0.05) and greater expression levels (P < 0.05) in the H group than in the L group. Additionally, hypermethylation was observed in the gene body region of MEF2C, as was a low expression level, in the H group (P < 0.05). CONCLUSIONS: These results suggest that the differences in the ADGs of Duroc pigs fed the same diet may be influenced by the methylation levels and expression levels of genes related to skeletal muscle development.

Iron 3D-Orbital Configuration Dependent Electron Transfer for Efficient Fenton-Like Catalysis.

Transition metals are excellent active sites to activate peroxymonosulfate (PMS) for water treatment, but the favorable electronic structures governing  reaction mechanism still remain elusive. Herein, the authors construct typical d-orbital configurations on iron octahedral (FeOh ) and tetrahedral (FeTd ) sites in spinel ZnFe2 O4 and FeAl2 O4 , respectively. ZnFe2 O4 (136.58 min-1 F-1 cm2 ) presented higher specific activity than FeAl2 O4 (97.47 min-1 F-1 cm2 ) for tetracycline removal by PMS activation. Considering orbital features of charge amount, spin state, and orbital arrangement by magnetic spectroscopic analysis, ZnFe2 O4 has a larger bond order to decompose PMS. Using this descriptor, high-spin FeOh is assumed to activate PMS mainly to produce nonradical reactive oxygen species (ROS) while high-spin FeTd prefers to induce radical species. This hypothesis is confirmed by the selective predominant ROS of 1 O2 on ZnFe2 O4 and O2 •- on FeAl2 O4 via quenching experiments. Electrochemical determinations reveal that FeOh has superior capability than FeTd for feasible valence transformation of iron cations and fast interfacial electron transfer. DFT calculations further suggest octahedral d-orbital configuration of ZnFe2 O4 is beneficial to enhancing Fe-O covalence for electron exchange. This work attempts to understand the d-orbital configuration-dependent PMS activation to design efficient catalysts.

Diffusive metasurfaces based on transverse magnetized ferrite for reduction of radar cross section.

Diffusive metasurfaces have attracted a great deal of interest in recent years for their promising radar cross section reduction ability. In this work, we proposed a methodology for designing non-tunable and tunable diffusive metasurfaces with transverse magnetized ferrite (TMF). The metasurfaces are two-dimensional arrays configured by metal plates and TMFs backed by metal plates, where the TMFs are functioned as perfect magnetic conductor and magnetic absorbers in lossless and lossy cases, respectively. The designed tunable metasurface allows for control of the operating frequency by adjusting the biased magnetic field, while the non-tunable version provides a wider operation band. This paper demonstrates that the ferrite-based metasurface have exotic stealth performance at microwave frequencies and offers a new approach to design stealth structures.

Full-Length Transcriptome Analysis of Skeletal Muscle of Jiangquan Black Pig at Different Developmental Stages.

Skeletal muscle grows in response to a combination of genetic and environmental factors, and its growth and development influence the quality of pork. Elucidating the molecular mechanisms regulating the growth and development of skeletal muscle is of great significance to both animal husbandry and farm management. The Jiangquan black pig is an excellent pig breed based on the original Yimeng black pig, importing the genes of the Duroc pig for meat traits, and cultivated through years of scientific selection and breeding. In this study, full-length transcriptome sequencing was performed on three growth stages of Jiangquan black pigs, aiming to study the developmental changes in Jiangquan black pigs at different developmental stages at the molecular level and to screen the key genes affecting the growth of skeletal muscle in Jiangquan black pigs. We performed an enrichment analysis of genes showing differential expression and constructed a protein-protein interaction network with the aim of identifying core genes involved in the development of Jiangquan black pigs. Notably, genes such as TNNI2, TMOD4, PLDIM3, MYOZ1, and MYH1 may be potential regulators of muscle development in Jiangquan black pigs. Our results contribute to the understanding of the molecular mechanisms of skeletal muscle development in this pig breed, which will facilitate molecular breeding efforts and the development of pig breeds to meet the needs of the livestock industry.

Effect of surfactant's charge properties on behavior, physiology, and biochemistry and the release of microcystins of Microcystis aeruginosa.

Surfactant pollution is escalatitheng in eutrophic waters, but the effect of surfactant charge properties on the physiological and biochemical properties of toxin-producing microalgae remains inadequately explored. To address this gap, this study explores the effects and mechanisms of three common surfactants-cetyltrimethylammonium bromide (CTAB, cationic), sodium dodecyl sulfate (SDS, anionic), and Triton X-100 (nonionic)-found in surface waters, on the agglomeration behavior, physiological indicators, and Microcystin-LR (MC-LR) release of Microcystis aeruginosa (M. aeruginosa) by using UV-visible spectroscope, Malvern Zetasizer, fluorescence spectrometer, etc. Results suggest that charge properties significantly affect cyanobacterial aggregation and cellular metabolism. The CTAB-treated group demonstrates a ∼5.74 and ∼9.74 times higher aggregation effect compared to Triton X-100 and SDS (300 mg/L for 180 min) due to strong electrostatic attraction. Triton X-100 outperforms CTAB and SDS in polysaccharide extraction, attributed to its higher water solubility and lower critical micelle concentration. CTAB stimulates cyanobacteria to secrete proteins, xanthohumic acid, and humic acids to maintain normal physiological cells. Additionally, the results of SEM and ion content showed that CTAB damages the cell membrane, resulting in a ∼90% increase in the release of intracellular MC-LR without cell disintegration. Ionic analyses confirm that all three surfactants alter cell membrane permeability and disrupt ionic metabolic pathways in microalgae. This study highlights the relationship between the surface charge properties of typical surfactants and the dispersion/agglomeration behavior of cyanobacteria. It provides insights into the impact mechanism of exogenous surfactants on toxic algae production in eutrophic water bodies, offering theoretical references for managing surfactant pollution and treating algae blooms.

Community Structure and Water Quality Assessment of Benthic Macroinvertebrates in Hongze Lake.

This study investigated the species, density, biomass and physicochemical factors of benthic macroinvertebrates in Hongze Lake from 2016 to 2020. Redundancy analysis (RDA) was used to analyze the relationship between physicochemical parameters and the community structure of macroinvertebrates. Macroinvertebrate-based indices were used to evaluate the water quality conditions in Hongze Lake. The results showed that a total of 50 benthic species (10 annelids, 21 arthropods and 19 mollusks) were collected. The community structure of benthic macroinvertebrates varied in time and space. The dominant species were Limnodrilus hoffmeisteri (L.hoffmeisteri), Corbicula fluminea (C.fluminea), Nephtys oligobranchia (N.oligobranchia). In 2016, arthropods such as Grandidierella sp. were the dominant species of benthos in Hongze Lake while annelids and mollusks dominated from 2017 to 2020, such as L.hoffmeisteri, N.oligobranchia, C.fluminea. The benthic fauna of Chengzi Lake and Lihewa District were relatively abundant and showed slight variation, while the benthic macroinvertebrates of the Crossing the water area were few and varied greatly. RDA showed that changes in benthic macroinvertebrate structure were significantly correlated with dissolved oxygen (DO), Pondus Hydrogenii (pH) and transparency (SD). The Shannon Wiener, Pielou, and Margalef indices indicate that Hongze Lake is currently in a moderately polluted state. Future studies should focus on the combined effects of various physicochemical indicators and other environmental factors on benthic communities.

Co-transport of arsenic and micro/nano-plastics in saturated soil.

Contaminants can co-exist and migrate together in the environment, causing complex (and sometimes unexpected) transport dynamics which challenge the efficient remediation of individual contaminants. The co-transport dynamics, however, remained obscure for some contaminants, such as arsenic and micro/nano-plastics (MNPs). To fill this knowledge gap, this study explored the co-transport dynamics of arsenic and MNP particles in saturated soil by combining laboratory experiments and stochastic model analysis. Isothermal adsorption and sand column transport experiments showed that the adsorption of arsenic by MNP particles followed the Freundlich model, with a maximum adsorption of 2.425 mg/g for the MNP particles with a diameter of 100 nm. In the presence of MNP particles, the efflux concentration of arsenic ions declined due to adsorption, where the decline rate decreased with the increasing MNP size and increased with the increasing adsorption capacity. Experimental results also showed that the 100 nm nano-plastic particles prohibited arsenic transport in saturated sand columns, while the 5 µm microplastics enhanced arsenic transport due to electrostatic adsorption and media pore plugging. A tempered time fractional advective-dispersion equation was then proposed to quantify the observed breakthrough curves of arsenic. The results showed that this model can reliably capture the co-transport behavior of arsenic with MNPs in the saturated soil with all coefficients of determination over 0.97, and particularly, the small MNP particles facilitated anomalous transport of arsenic. This study therefore improved the understanding and quantification of the co-transport of arsenic and MNPs in soil.

Nomogram for the acute exacerbation of acetylcholine receptor antibody-positive generalized myasthenia gravis.

BACKGROUND AND OBJECTIVE: An acute exacerbation of myasthenia gravis (MG) can lead to the life-threatening myasthenia crisis which can increase the in-hospital mortality. This study aimed to clarify the correlative factor of the severity and activity of MG and the predictors of its exacerbation. METHODS: A prospective study was conducted to compare the clinical characteristics of acetylcholine receptor antibody (AChR-Ab)-positive generalized MG during acute exacerbation (AE) and in a stable state (SS). Logistic regression was used to determine risk factors, and a nomogram was developed. RESULTS: A total of 97 AChR-Ab MG patients were enrolled, of whom 44 had AE and 53 were in SS. The concentrations of AChR-Ab were 35.24 (23.26, 42.52) nmol/L and 19.51 (8.30, 36.93) nmol/L in the AE and SS groups (P = 0.005), respectively. The receiver operating characteristic curve showed that a single AChR-Ab predicted severity and acute exacerbation, with an area under the curve (AUC) of 0.679. Logistic regression analysis showed that, in addition to AChR-Ab (P = 0.018), bulbar symptoms (P = 0.001), interleukin (IL)-6 (P = 0.025), CD4+/CD8+ T cell ratio (P = 0.031), and CD19+ B cell proportion (P = 0.019) were independent risk factors for acute exacerbation of MG. The developed nomogram had an AUC of 0.878. The Hosmer and Lemeshow chi-square test was 4.37 (P = 0.929). CONCLUSION: AChR-Ab concentration was positively correlated with the severity and activity of MG. AChR-Ab concentration, alongside bulbar symptoms, IL-6 concentration, CD4+/CD8+ T cell ratio, and CD19+ B cell proportion can predict the acute exacerbation of MG.

Learning-Based IRS-Assisted Secure Transmission for Mine IoTs.

Mine Internet of Things (MIoT) devices in intelligent mines often face substantial signal attenuation due to challenging operating conditions. The openness of wireless communication also makes it susceptible to smart attackers, such as active eavesdroppers. The attackers can disrupt equipment operations, compromise production safety, and exfiltrate sensitive environmental data. To address these challenges, we propose an intelligent reflecting surface (IRS)-assisted secure transmission system for an MIoT device which enhances the security and reliability of wireless communication in challenging mining environments. We develop a joint optimization problem for the IRS phase shifts and transmit power, with the goal of enhancing legitimate transmission while suppressing eavesdropping. To accommodate time-varying channel conditions, we propose a reinforcement learning (RL)-based IRS-assisted secure transmission scheme that enables MIoT device to optimize both the IRS reflecting coefficients and transmit power for optimal transmission policy in dynamic environments. We adopt the deep deterministic policy gradient (DDPG) algorithm to explore the optimal transmission policy in continuous space. This can reduce the discretization error caused by traditional RL methods. The simulation results indicate that our proposed scheme achieves superior system utility compared with both the IRS-free (IF) scheme and the IRS randomly configured (IRC) scheme. These results demonstrate the effectiveness and practical relevance of our contributions, proving that implementing IRS in MIoT wireless communication can enhance safety, security, and efficiency in the mining industry.

Indoor exposure to polycyclic aromatic hydrocarbons associated with solid fuel use in rural China.

Polycyclic aromatic hydrocarbons (PAHs) are widespread environmental contaminants associated with various health risks including lung cancer. Indoor exposure to PAHs, particularly from the indoor burning of fuels, is significant; however, long-term large-scale assessments of indoor PAHs are hampered by high costs and time-consuming in field sampling and laboratory experiments. A simple fuel-based approach and statistical regression models were developed as a trial to predict indoor BaP, as a typical PAH, in China, and consequently spatiotemporal variations in indoor BaP and indoor exposure contributions were discussed. The results show that the national population-weighted indoor BaP concentration has decreased substantially from 46.1 ng/m3 in 1992 to 6.60 ng/m3 in 2017, primarily due to the increased use of clean energies for cooking and heating. Indoor BaP exposure contributed to > 70% of the total inhalation exposure in most cities, particularly in regions where solid fuels are widely utilized. With limited experimental observation data in building statistical models, quantitative results of the study are associated with high uncertainties; however, the study undoubtedly supports effective countermeasures on indoor PAHs from solid fuel use and the importance of promoting clean household energy usage to improve household air quality.

Structural characteristics of zooplankton communities in Hongze Lake driven by water environmental factors from 2016 to 2020.

This study investigated zooplankton species, density, biomass, and water physicochemical factors in Hongze Lake between 2016 and 2020. The correlation between zooplankton community changes and physicochemical factors was explored using canonical correspondence analysis and Spearman correlation analysis. The investigation found 48 species of protozoa, 52 species of rotifers, 36 species of cladocera, and 32 species of copepoda. The yearly mean density fluctuated between 529.01 and 2234.51 individuals per liter. The yearly mean zooplankton biomass was 950.14 mg/L, ranging from 271.92 to 1365.835 mg/L. A high diversity of zooplankton was found in the Overwater Area, with a large proportion of protozoa and copepoda. Correlation analysis revealed that nitrogen content, pH, water temperature, chemical oxygen demand, biochemical oxygen demand, water transparency, and chlorophyll a were important factors influencing the distribution of zooplankton in Hongze Lake. These factors collectively contributed to the evolution of the zooplankton community structure in Hongze Lake.

Characterization of a Novel Artemisinin Algicidal Particle and Its Inhibitory Effect on Microcystis aeruginosa.

A new artemisinin sustained-release particle (ASP) was developed that significantly inhibits Microcystis aeruginosa (M. aeruginosa) growth. The physical and chemical properties of ASPs were characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), differential scanning calorimetry, and thermogravimetry (DSC-TG). The results demonstrated that ASPs are thermally stable and have sustained-release properties. On the sixth day, the ASPs (0.2 g L-1) inhibited M. aeruginosa with an inhibition rate (IR) greater than 70%. Additionally, ASPs inhibited M. aeruginosa without increasing microcystin-LR release (MC-LR). This research offers a novel approach to the management of cyanobacterial blooms.

Effect of Metal Cations on Colloids-Microcystin-LR Interaction.

Colloidal particles, mixture with continuous molecular weight distribution and multiple organic components, is widespread in lake and have significant impact on the retention, migration, transportation, and fate of contaminants in lake ecosystems. Here we extract sedimentary colloids from algal growth dominant area (AD) in Taihu Lake and further separated into four different particle size ranges by cross-flow ultra-filtration (CFUF). The interaction mechanism between colloids and Microcystin-LR (MC-LR) was investigated under different cation conditions by dialysis equilibrium experiment method. Adsorption kinetics research shows the adsorption of MC-LR by colloids follows second-order kinetics and can be simulated by Freundlich isotherms. The effects of different cations on colloids-MC-LR interaction shows the addition of Mg(II) decreased colloids-MC-LR interaction, while Cu(II) increased colloids-MC-LR binding. MC-LR also increased Cu(II) binding to colloids, while MC-LR decreased Mg(II) binding. Therefore, different effect of cations to colloids-MC-LR interaction was proposed.

Photocatalysis Combined with Microalgae to Promote the Degradation and Detoxification of Tetracycline Hydrochloride.

The continuous discharge of antibiotics into the environment poses a serious threat to the ecological environment and human health. In this study, photocatalysis and microalgae were combined to study the removal of tetracycline hydrochloride (TCH) and its photodegradation intermediates in water. The results showed that after photocatalytic treatment, the removal rate of TCH reached 80%, but the mineralization rate was only 17.7%. While Chlorella sp. alone had poor tolerance to high concentrations of TCH, the combined treatment of photocatalysis and microalgae completely removed TCH and increased the mineralization efficiency to 35.0%. Increased cell density was observed, indicating that TCH and the intermediates produced in the photocatalysis process could be utilized by algae for growth. Meanwhile, TCH degradation pathways were proposed based on Liquid Chromatograph Mass Spectrometer analysis, and the toxicity of intermediates detected was predicted using ECOSAR software, which showed that the type and quantity of highly toxic intermediates decreased significantly after subsequent algal treatment. The results demonstrate that photocatalysis and microalgae combined treatment is an efficient and eco-friendly method for the removal of antibiotics in water.

Occurrence, partition behavior, source and ecological risk assessment of nitro-PAHs in the sediment and water of Taige Canal, China.

Nitrated polycyclic aromatic hydrocarbons (NPAHs) are widespread organic pollutants that possess carcinogenic and mutagenic properties, so they may pose a risk to the environment and human health. In this study, the concentrations of 15 NPAHs and 16 polycyclic aromatic hydrocarbons (PAHs) in 30 surface water samples and 26 sediment samples were measured in 2018 from the Taige Canal, one of the main rivers flowing into Taihu Lake, China. The total NPAH concentrations in water and sediment ranged from 14.7 to 235 ng/L and 22.9 to 96.5 ng/g dw, respectively. 9-nitrophenanthrene (nd-76.3 ng/L) was the dominant compound in surface water, while 2+3-nitrofluoranthene (1.73-18.1 ng/g dw) dominated in sediment. Among PAHs, concentration ranging from 1,097 to 2,981 ng/L and 1,089 to 4,489 ng/g dw in surface water and sediment, respectively. There was a strong positive correlation between the log octanol-water partition coefficient (Kow) and log sediment-water partition coefficient due to hydrophobic interaction. The fugacity fraction value increased with the decrease of log Kow, and chrysene was transferred from water into sediment. The residual NPAHs in surface water and sediment of the Taige Canal have partial correlation. Diesel engine and coal combustion emissions were probably the principal sources of NPAHs in surface water and sediment. The results of ecological risk assessment showed that some NPAHs in water (e.g, 1-nitropyrene and 6-nitrochrysene) and sediment (e.g., 2-nitrobiphenyl, 5-nitroacenaphthene, 9-nitrophenanthrene and 2+3-nitrofluoranthene) had moderate ecological risks, which should be of concern.

Pose Estimation for Visible Light Systems Using a Quadrature Angular Diversity Aperture Receiver.

The quadrature angular diversity aperture (QADA) receiver, consisting of a quadrant photodiode (QPD) and an aperture placed above the QPD, has been investigated for pose estimation for visible light systems. Current work on pose estimation for the QADA receiver uses classical camera sensor algorithms well known in computer vision. To this end, however, the light spot center first has to be obtained based on the RSS. However, this is less straightforward than for camera sensors, as in contrast to such sensors where the relationships are linear, the RSS output from the QADA is a non-linear function of the light spot position. When applying closed form solutions or iterative methods for cameras on a QADA, the non-linearity will degrade their performance. Furthermore, since in practice the aperture is not always perfectly aligned with the QPD, a procedure to calibrate the receiver is needed. Current work on calibration requires additional sophisticated equipment to measure the pose during calibration, which increases the difficulty of implementation. In this paper, we target the above problems for pose estimation and calibration of the QADA receiver. To this end, we first study the effect of the strategy of differencing and normalization on the probability density function (PDF), a commonly applied strategy for the QPD's robustness against RSS variation, and it is shown that the applied strategy results in a complex PDF, which makes an effective and efficient estimation hard to achieve. Therefore, we derive an approximated PDF in a simple closed-form, based on which the calibration and the pose estimation algorithms using the least squares principle are proposed. The proposed calibration does not require any information about the pose of the receiver and is robust to variation of the received power and imperfect knowledge of the radiation pattern of the LED, making it easy to implement. We also derive the corresponding Cramér-Rao lower bound on the misalignment to benchmark the performance of the misalignment and to serve as an indicator to determine the required signal-to-noise ratio (SNR) or number of LEDs to obtain a desired accuracy. The calibration and pose estimation are evaluated by means of a Monte Carlo simulation. Computer simulations show that this theoretical bound is close to the RMSE of the proposed estimator and that the proposed pose estimator outperforms the PnP algorithm.

Removal kinetics and mechanisms of tetrabromobisphenol A (TBBPA) by HA-n-FeS colloids in the absence and presence of oxygen.

The colloid of ferrous sulfide modified by humic acid (HA-n-FeS) shows good reduction and immobilization efficiency for variable-valence heavy metals in wastewater. The removal efficiency of HA-n-FeS for halogenated organic pollutants, however, remains unclear, especially in the absence and presence of oxygen. This study addressed this issue by exploring the effect and mechanism of dissolved oxygen on the degradation of tetrabromobisphenol A (TBBPA) by the HA-n-FeS colloid in water. The results showed that the removal efficiency of different concentrations of TBBPA (5,10, and 20 µm) by the HA-n-FeS colloid was 33.16%, 20.48%, and 22.37% in the absence of oxygen, respectively. When TBBPA reacted with the HA-n-FeS colloid, the concentration of Fe(II) and S(-II) remained stable. The adsorption of HA-n-FeS was the main mechanism of removing TBBPA in the absence of oxygen. In the presence of oxygen, the removal efficiency of TBBPA by the HA-n-FeS colloid was 82.37%, 56.80%, and 43.78% (for the above-mentioned TBBPA concentrations), respectively. In addition, the removal capacity of TBBPA by HA-n-FeS was 39.63, 52.21, and 89.75 mg/g, respectively. The concentration of Fe(II) and S(-II) decreased rapidly in time. Among them, the HA-n-FeS colloid removed part of the TBBPA through chemical adsorption. The main way of chemical adsorption was pore adsorption and functional group (olefin CC, phenolic hydroxyl group O-H, alcohol group C-O) combination. Besides, the HA-n-FeS colloid degraded part of the TBBPA into BPA through reduction, in which 17.72% of TBBPA was removed by the reduction of HA-n-FeS colloid. Fe(II) was the main contributor to the reductive degradation of TBBPA. Furthermore, active species (1O2 and •O2-) played a minor role in the removal of TBBPA by the HA-n-FeS colloids with oxygen, where 13% of TBBPA was removed by 1O2 and •O2-. Therefore, in practical applications, the aeration method can be used to significantly improve the removal efficiency of TBBPA by HA-n-FeS colloids in water.

Inactivation Mechanism of Algal Chlorophyll by Allelochemical Quercetin.

Cyanobacteria harmful algal blooms (CyanoHABs) are a global concern. Application of allelochemicals is a promising solution for cyanobacteria control, due to its high efficiency, low cost and ecological safety. Flavonoids (natural polyphenols produced by aquatic plants) are reported capable of effectively inhibiting the growth of algae; however, the molecular mechanism of algae chlorophyll inactivation is still unclear. In this study, quercetin was used as a typical flavonoid, to investigate the inactivation effect of allelochemical on Microcystis aeruginosa chlorophyll a. The absorption and fluorescence spectra showed that chlorophyll reacted with quercetin to form pheophytin, and the formation rate of pheophytin increased with increasing quercetin concentration (1 × 10-5-1 × 10-2 M). FTIR spectra and DFT calculation showed that Mg2+ complexed with the 3-OH and 4-C = O groups in the quercetin ring C so that chlorophyll was inactivated due to the loss of Mg2+ ions. Overall, this study revealed that quercetin inactivated chlorophyll a of cyanobacteria by capturing Mg2+ ions, providing insights into the molecular mechanisms of algal bloom control by allelochemicals.

New Bounds on Capacity Region of Multiple Access Channels in Visible Light Communications.

In this paper, we propose new inner and outer bounds of the capacity region for multiple access channels in visible light communication (VLC) networks under both peak and average optical power constraints. Specifically, the proposed inner bounds are established by employing the single-user capacity achieving input distribution for each user. The proposed outer bounds are derived by determining single-user capacities for each user and calculating a sum capacity upper bound by relaxing the input constraints. Numerical results show that the proposed new bounds are extremely tight and outperform existing bounds over wide ranges of SNRs.