Biochar affects methylmercury production and bioaccumulation in paddy soils: Insights from soil-derived dissolved organic matter.

Biochar has been used increasingly as a soil additive to control mercury (Hg) pollution in paddy rice fields. As the most active component of soil organic matter, soil dissolved organic matter (DOM) plays a vital role in the environmental fate of contaminants. However, there are very few studies to determine the impact of biochar on the Hg cycle in rice paddies using insights from DOM. This study used original and modified biochar to investigate their effect on DOM dynamics and their potential impact on methylmercury (MeHg) production and bioaccumulation in rice plants. Porewater DOM was collected to analyze the variations in soil-derived DOM in paddy soils. The results showed that the addition of biochar, whether in original or modified form, significantly reduced the bioaccumulation of MeHg in rice plants, especially in hulls and grains (p<0.05). However, MeHg production in soils was only inhibited by the modified biochar. Biochar addition induced a significant increase in DOM's aromaticity and molecular weight (p<0.05), which decreased Hg bioavailability. Furthermore, enhanced microbial activity was also observed in DOM (p<0.05), further increasing MeHg production in the soil. Thus, the effect of biochar on the fate of Hg cycle involves competition between the two different roles of DOM. This study identified a specific mechanism by which biochar affects Hg behavior in rice paddy soil and contributes to understanding the more general influence of biochar in agriculture and contaminant remediation.

Effect of GO on the Structure and Properties of PEG/Biochar Phase Change Composites.

In recent years, phase change materials (PCMs) have been widely used in waste heat utilization, buildings, and solar and wind energy, but with a huge limitation from the low thermal conductivity, photothermal conversion efficiency, and low latent heat. Organic PCMs are eyecatching because of its high latent heat storage capability and reliability, but they still suffer from a lack of photothermal conversion and sharp stability. Here, we prepared sharp-stable PCMs by establishing a carbon material frame system consisting of graphene oxide (GO) and biochar. In particular, surfactants (CTAB, KH-560 and KH-570) were employed to improve the dispersity of GO in PEG. The differential scanning calorimetry results shows that the latent heat of PEG modified by CTAB grafted GO (PGO-CTAB) was the highest (191.36 J/g) and increased by 18.31% compared to that of pure PEG (161.74 J/g). After encapsulation of PGO-CTAB in biochar, the obtained composite PCM with the amount of biochar and PGO-CTAB in weight ratio 4:6 (PGO-CTAB/CS6(6)) possesses relatively high latent heat 106.51 J/g with good leak resistance and thermal stability, and with obviously enhanced thermal conductivity (0.337 W/(m·K)) and photothermal conversion efficiency (77.43%), which were higher than that of PEG6000 (0.325 W/(m·K), 44.63%). The enhancement mechanism of heat transfer and photothermal conversion on the composite PCM is discussed.

Significant Improvement of Adsorption for Phosphate Removal by Lanthanum-Loaded Biochar.

Due to eutrophication, removing phosphate ions from wastewater has received a lot of attention. In order to improve the phosphorus adsorption capacity of the material, this study used biomass pyrolysis to create a series of biochars modified with metal chloride ions. In accordance with adsorption tests, lanthanum-loaded biochar (LCBC) had a significant phosphorus adsorption capacity of approximately 666.67 mg/g, which was 30 times greater than that of pristine biochar. Adsorption kinetic analysis revealed that the LCBC's adsorption process could be fitted to the pseudo-secondary kinetic equation, indicating that chemical processes were primarily responsible for controlling the adsorption process. Zeta potential, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy analysis showed that the main adsorption mechanism of LCBC for phosphate removal was electrostatic attraction of protonated H+ with negatively charged mono-hydrogen phosphate and dihydrogen phosphate ions and complexation reaction of the C=O on the carboxyl group and P=O on the phosphate group with the oxygen on the phosphate group and hydroxyl group. According to regeneration performance results, LCBC performed relatively better than as-prepared adsorbents, and the phosphate removal rate was approximately 75.1% after the fifth regeneration cycle. The study provided a potential approach for creating and preparing an adsorbent with high adsorption for phosphate removal.

Effects of biochar pyrolysis temperature on thermal properties of polyethylene glycol/biochar composites as shape-stable biocomposite phase change materials.

The characteristics of biochar are of great significance to its application in the field of phase change energy storage. The objective of this research was to explore the effects of pyrolysis temperature on the characteristics of a biochar matrix and further on the heat energy storage properties of the promising green biochar-supported shape-stable biocomposite PCMs (ss-BCPCMs). Corn straw biochars (CSBCs) obtained under different pyrolysis conditions were loaded with polyethylene glycol (PEG) by an ultrasound-assisted vacuum impregnation method. The micro-morphology, specific surface area, pore structure and surface properties of biochar have been characterized and analyzed by scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) method and Fourier transform infrared spectroscopy (FTIR). The thermal properties (chemical stability, latent heat storage, thermal conductivity, thermal stability, and thermal insulation) of PEG/CSBC composites have been characterized by FTIR, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and laser flash analysis (LFA). The study revealed that both pore structure and surface activity of biochar are key factors affecting the energy storage performance of biochar-based ss-BCPCMs. The obtained PEG/CSBC composite showed a high latent heat storage up to 100.2 J g-1, good shape stability and leakage resistance, suggesting its high thermal storage stability that is beneficial for thermal energy storage applications. In addition, its excellent photothermal conversion efficiency (68.95%) provides application potential in photothermal energy storage.

Thermal degradation behavior and flame retardant properties of PET/DiDOPO conjugated flame retardant composites.

PET/DIDOPO conjugated flame retardant composites were prepared by melt blending of styrene bridged DOPO (DIDOPO) into polyethylene terephthalate (PET). The flame retardancy, rheological behavior, and thermal degradation behavior of the composite were characterized by vertical combustion test (UL-94), limit oxygen index test (LOI), rotational rheometer, and thermogravimetry (TG). The results showed that the flame retardant composite with V-0 grade was obtained when the amount of DIDOPO is 12.5wt%, and the corresponding LOI value was 56.87% higher than that of PET. The thermogravimetry-fourier infrared spectroscopy (TG-FTIR) test results showed that DIDOPO could promote the degradation of PET/DIDOPO materials, and release phosphorus-containing free radicals to quench the flame, therefore slowing down the combustion process, and mainly playing the key flame retardant role in gas-phase.

catena-Poly[[(2,2'-bipyridine-κN,N')cadmium]-µ(3)-4-nitro-phthalato-κO:O',O'':O'''].

In the title polymeric compound, [Cd(C(8)H(3)NO(6))(C(10)H(8)N(2))](n), two O atoms from both carboxyl-ate groups of a nitro-phthalate anion coordinate to the Cd(II) cation, forming a seven-membered chelate ring and two carboxyl-ate O atoms from another two nitro-phthalate anions and a 2,2'-bipyridine ligand coordinate to the Cd cation to complete the distorted octa-hedral coordination geometry. The carboxyl-ate groups of the nitro-phthalate anion adopt a syn-anti bridging mode, linking adjacent Cd(II) cations and forming a polymeric chain running along the a axis. Weak intra- and inter-molecular C-H⋯O hydrogen bonding is present in the crystal structure.

Stability of filament-wound hyperbolic flexible pipes under internal pressure based on non-geodesic winding.

Filament-wound flexible pipes are widely used to transport fluid in pipeline systems, proved extremely useful in marine engineering. The hyperbolic flexible pipes have good vibration suppression performance, but they are easily deformed under internal pressure. This paper focuses on the stability of hyperbolic flexible pipes based on the composite Reissner shell theory and the transfer-matrix method. The nonlinear stretch of the reinforced filament and the fiber bridge effect are considered in the model. The calculation results show that a large winding angle reduces the deformation and the meridional stress. The available initial winding angle is limited by the geometry and the slippage coefficient of flexible pipe. The reinforced filament of high tensile modulus will reduce the deformation of the pipe. Compared with the geodesic winding trajectory, non-geodesic winding trajectories improves the stability of the pipe. The theoretical result is verified by the finite element analysis. The investigation method and results present in this paper will guide the design and optimization of more novel flexible pipes in the future.

Four Prognosis-Associated lncRNAs Serve as Biomarkers in Ovarian Cancer.

Long non-coding RNAs (lncRNAs) play crucial roles in ovarian cancer (OC) development. However, prognosis-associated lncRNAs (PALs) for OC have not been completely elucidated. Our study aimed to identify the PAL signature of OC. A total of 663 differentially expressed lncRNAs were identified in the databases. According to the weighted gene coexpression analysis, the highly correlated genes were clustered into seven modules related to the clinical phenotype of OC. A total of 25 lncRNAs that were significantly related to overall survival were screened based on univariate Cox regression analysis. The prognostic risk model constructed contained seven PALs based on the parameter λmin, which could stratify OC patients into two risk groups. The results showed that the risk groups had different overall survival rates in both The Cancer Genome Atlas (TCGA) and two verified Gene Expression Omnibus (GEO) databases. Univariate and multivariate Cox regression analyses confirmed that the risk model was an independent risk factor for OC. Gene enrichment analysis revealed that the identified genes were involved in some pathways of malignancy. The competitive endogenous RNA (ceRNA) network included five PALs, of which four were selected for cell function assays. The four PALs were downregulated in 33 collected OC tissues and 3 OC cell lines relative to the control. They were shown to regulate the proliferative, migratory, and invasive potential of OC cells via Cell Counting Kit-8 (CCK-8) and transwell assays. Our study fills the gaps of the four PALs in OC, which are worthy of further study.

[Effects of Chitosan-modified Biochar on Formation of Methylmercury in Paddy Soils and Its Accumulation in Rice].

Rice is well known to accumulate methylmercury (MeHg) and the consumption of rice in mercury (Hg) polluted areas has been confirmed to be a primary source of MeHg exposure. Therefore, how to inhibit the formation and accumulation of MeHg in the paddy field system needs to be solved urgently. Chitosan modified biochar, a potential inhibitor, was selected in this study to explore its effect on MeHg production and accumulation in the paddy field system by analyzing the mercury content of interstitial water, soil, and rice plant tissues. The results showed that the addition of chitosan modified biochar could significantly reduce MeHg concentration in the soil with the decreased methylation rate of 51.1%-79.1%, and could also decrease the total mercury (THg) and MeHg content of interstitial water. At the maturation stage of rice, the MeHg content of rice roots treated with chitosan modified biochar (CMBC) was 73.1% lower than without biochar (CK1) and 62.0% lower than with unmodified biochar (CK2), and the rice MeHg was 75.8% lower than that of CK1 and 72.9% lower than that of CK2. In addition, the application of biochar could promote the growth of rice with the plant biomass of CMBC and CK2 of 1.6 and 1.7 times higher than that of CK1. Generally, the application of chitosan modified biochar into paddy soil could not only promote the growth of rice, but also inhibit the accumulation of MeHg in rice, suggesting that the chitosan modified biochar has a certain application value in the inhibition of the MeHg formation and accumulation in paddy field system.

Estimation of the biogeochemical reactivities of dissolved organic matter from modified biochars using color.

Modified biochar is widely used as a soil amendment in agricultural systems to improve crop yields and remove environmental pollutants. The water-soluble fraction of biochar, called biochar-derived dissolved organic matter (DOMBC), is the most active biochar component. However, the correlation between the optical properties of DOMBC and its biogeochemical activity remain unclear. In this study, one biochar and six modified derivatives were used to extract DOMBC and characterize its optical properties. The biogeochemical reactivities of DOMBC were determined using biodegradation, photodegradation, and electron-donating capacity assays. The results show that modification changes the biochar characteristics, leading to a variety of DOMBC properties. The DOMBC from modified biochars degrades more rapidly than the original biochar. On the other hand, modification reduces the redox functional groups in DOMBC, resulting in a lower electron-donating capacity of DOM samples. However, the modifications did not seem to affect photodegradation. Not all spectral parameters provide information about the correlations between the DOMBC properties and biogeochemical reactivity. However, two fundamental properties, that is, the specific UV absorbance at 254 nm (SUVA254, showing aromaticity) and spectral slopes over the ranges of 275-295 nm of the UV absorbance (S275-295, showing molecular weight), are the dominant factors affecting the biodegradation and electron-donating capacities of DOMBC. In this study, a rapid and straightforward method is presented, which can be used to characterize DOMBC and predict the reactivity of biochar that is used as an environmental amendment to minimize toxic organic compounds.

Fabrication of reinforced and toughened PC/PMMA composites by tuning the migration and selective location of graphenes during melt blending.

In this work, we creatively obtained reinforced and toughened PC/PMMA/GNs composites by tuning the migration and selective location of graphene nanosheets (GNs) during melt blending. TEM results revealed that the migration of GNs in PC/PMMA blends during melt blending always existed no matter how the GNs were introduced, and most of them exclusively localized at the interface of PC and PMMA phase due to interfacial effects. The migration of GNs could refine the size of the dispersed phase, and the exclusive localization of GNs at the interface show obvious interfacial compatibilizing effects, leading to improved mechanical properties of the composites. It was found that the composite prepared by one-step compounding showed significant enhanced strength and toughness with addition of mere 0.05 wt% GNs and the tensile strength and elongation of the composite increased by about 62.96% and 94.54%, respectively as compared to the PC/PMMA blends. Moreover, the composite prepared by one-step compounding also showed improved thermal conductivity at the same time, indicating excellent comprehensive properties. It is believed that tuning the migration and selective localization of GNs open perspectives for the development of high-performance polymer composites.

Describing the toxicity and sources and the remediation technologies for mercury-contaminated soil.

Mercury (Hg) is a natural element and its compounds are found as inorganic and organic forms in the environment. The different Hg forms (e.g., methylmercury (MeHg)), are responsible for many adverse health effects, such as neurological and cardiovascular effects. The main source of Hg is from natural release. Nevertheless, with the development of industrialization and urbanization, Hg-contaminated soil mainly influenced by human activities (especially near mercury mining areas) has become a problem. Therefore, much more attention has been paid to the development and selection of various treatment methods to remediate Hg-contaminated soils. This paper presented a systematical review of the recent developments for the remediation of Hg-contaminated soils. Firstly, we briefly introduced the Hg chemistry, toxicity and the main human activity-related sources of mercury in soil. Then the advances in remediation technologies for removing Hg pollution from the soil were summarized. Usually, the remediation technology includes physical, chemical and biological remediation technology. Depending on this, we further classified these remediation technologies into six techniques, including thermal desorption, electrokinetic extraction, soil washing, chemical stabilization, phytoremediation and microbial technology. Finally, we also discussed the challenges and future perspectives of remediating Hg-contaminated soils.

Efficient removal of Cd(II) from aqueous solution by pinecone biochar: Sorption performance and governing mechanisms.

Cadmium (Cd) is one of the most harmful and widespread environmental pollutants. Despite decades-long research efforts, the remediation of water contaminated by Cd has remained a significant challenge. A novel carbon material, pinecone biochar, was previously hypothesized to be a promising adsorbent for Cd, while so far, it has received little attention. This study evaluated the sorption capacity of pinecone biochar through isotherm experiments. Based on Langmuir model, the adsorption maximum for Cd(II) was up to 92.7 mg g-1. The mechanism of Cd(II) adsorption on pinecone biochar was also explored through both thermodynamic and kinetics adsorption experiments, as well as both solution and solid-phase microstructure characterization. The solid-solution partitioning behaviour of Cd(II) fitted best with the Tόth model while the adsorption process followed a pseudo-second-order rate, suggesting that the Cd(II) adsorption on the pinecone biochar was mainly a chemisorption process. Microstructure characteristics and mechanism analysis further suggested that coprecipitation and surface complexation were the main mechanisms of Cd adsorption by biochar. Coprecipitation occurred mainly through the forms of Cd(OH)2 and CdCO3. Our results demonstrated that pinecone biochar was an efficient adsorbent which holds a huge potential for Cd(II) removal from aqueous solution.

Anti-inflammatory mechanism of total glycosides of Acanthopanax Giraldii.

OBJECTIVE: To study the anti-inflammatory mechanisms of total glycosides of Acanthopanax Giraldii (TGA). METHODS: The changes of prostaglandin E(2)(PGE(2)), tumor necrosis factor (TNF-alpha), nitric oxide (NO), and expressions of COX-1 mRNA and COX-2 mRNA in BALB/c mouse macrophages were observed by the radioimmunoassay, ELISA and nitric acid reduction and RT-PCR in the presence or absence of TGA. RESULTS: (1) TGA could significantly decrease the production of PGE(2)and NO in mouse peritoneal macrophages. The inhibitory rate to LPS-induced PGE(2)production was 87% (TGA 100 mg/L, P<0.05, vs. LPS) and 62% (TGA 20 mg/L, P<0.05, vs. LPS), respectively. The inhibitory rate of NO production in mouse peritoneal macrophages was 49% (TGA 100 mg/L, P<0.05, vs. LPS) and 21% (TGA 20 mg/L, P<0.05 vs. LPS), respectively. TGA could not inhibit LPS-induced TNF-alpha production in mouse peritoneal macrophages. (2) TGA also inhibited the expression of COX-1 and COX-2 mRNA in RAW264.7 cells. The inhibitory rate of TGA to COX-1 mRNA was 22% (TGA 100 mg/L, P<0.05, vs. blank). The inhibitory rate of TGA to COX-2 mRNA was 55% (TGA 20 mg/L, P<0.05, vs. LPS) and 100% (TGA 100 mg/L, P<0.01 vs. LPS), respectively. CONCLUSION: The anti-inflammatory mechanisms of TGA for inhibiting the production of NO and PGE(2)are through inhibiting COX-2 mRNA expression without TNF-alpha changes.

Effect of silane functionalized graphene prepared by a supercritical carbon dioxide process on the barrier properties of polyethylene terephthalate composite films.

In this work, a simple and eco-friendly strategy to modify graphene nanoplatelets (GNs) with different silane coupling agents using a supercritical carbon dioxide (Sc-CO2) process has been presented, and effect of the modified GNs on the oxygen transmission rate (OTR) and water vapor transmission rate (WVTR) of GN/PET composite films was studied. FT-IR, SEM, EDX and TG results indicated that Sc-CO2 process was an effective strategy to modify GNs with silane coupling agents. Addition of the modified GNs into PET matrix could greatly decrease the OTR and WVTR values of the GNs/PET composite films, and the WVTR of GNs560/PET composite film and OTR of GNs550/PET composite film were respectively decreased about 90.08% and 58.04%, as compared to those of GNs/PET composite film. It is found that the gas barrier property of GN/PET composites was attributed to not only the tortuous path effect caused by GNs themselves and the interfacial interaction, but also the affinity of binding bonds between GNs and the polymer to the gas molecules. It is believed that this work provided a strategy to design and prepare CN/polymer composites with high barrier properties.

Diverse genome structures of Salmonella paratyphi C.

BACKGROUND: Salmonella paratyphi C, like S. typhi, is adapted to humans and causes typhoid fever. Previously we reported different genome structures between two strains of S. paratyphi C, which suggests that S. paratyphi C might have a plastic genome (large DNA segments being organized in different orders or orientations on the genome). As many but not all host-adapted Salmonella pathogens have large genomic insertions as well as the supposedly resultant genomic rearrangements, bacterial genome plasticity presents an extraordinary evolutionary phenomenon. Events contributing to genomic plasticity, especially large insertions, may be associated with the formation of particular Salmonella pathogens. RESULTS: We constructed a high resolution genome map in S. paratyphi C strain RKS4594 and located four insertions totaling 176 kb (including the 90 kb SPI7) and seven deletions totaling 165 kb relative to S. typhimurium LT2. Two rearrangements were revealed, including an inversion of 1602 kb covering the ter region and the translocation of the 43 kb I-CeuI F fragment. The 23 wild type strains analyzed in this study exhibited diverse genome structures, mostly as a result of recombination between rrn genes. In at least two cases, the rearrangements involved recombination between genomic sites other than the rrn genes, possibly homologous genes in prophages. Two strains had a 20 kb deletion between rrlA and rrlB, which is a highly conservative region and no deletion has been reported in this region in any other Salmonella lineages. CONCLUSION: S. paratyphi C has diverse genome structures among different isolates, possibly as a result of large genomic insertions, e.g., SPI7. Although the Salmonella typhoid agents may not be more closely related among them than each of them to other Salmonella lineages, they may have evolved in similar ways, i.e., acquiring typhoid-associated genes followed by genome structure rearrangements. Comparison of multiple Salmonella typhoid agents at both single sequenced genome and population levels will facilitate the studies on the evolutionary process of typhoid pathogenesis, especially the identification of typhoid-associated genes.

Spontaneous conversion between mutL and 6 bpDeltamutL in Salmonella typhimurium LT7: association with genome diversification and possible roles in bacterial adaptation.

Previously, we reported the phenomenon of genome diversification in Salmonella typhimurium LT7, i.e., individual strains derived from LT7 kept changing the genome structure by inversions, translocations, duplications, and mutations. To elucidate the genetic basis, we sequenced selected genes of the mismatch repair (MMR) system for correlations between MMR defects and genome diversification. We chose S. typhimurium LT7 mutants 8111F2 and 9052D1 for mut gene sequence analyses and found that both mutants had a deletion of one of three tandem 6-bp repeats, GCTGGC GCTGGC GCTGGC, within mutL, which was designated 6 bpDeltamutL. mutS and mutH genes were unchanged in the mutants analyzed. Some sublines of 8111F2 and 9052D1 spontaneously stopped the genome diversification process at certain stages during single-colony restreaking passages, and in these strains the 6 bpDeltamutL genotype also became wild-type mutL. We conclude that conversion between mutL and 6 bpDeltamutL occurs spontaneously and that transient defects of mutL facilitate genome diversification without leading to the accumulation of multiple detrimental genetic changes. Spontaneous conversion between mutL and 6 bpDeltamutL may be an important mechanism used by bacteria to regulate genetic stability in adaptation to changing environments.

[Study on Jisi Yi'an (Medical Cases of Multitude Thought) of Yi Jusun, a famous doctor of Lingnan region].

Textual research was made on Jisi Yián (Medical Cases of Multitude Thought), a book of medical cases written by Yi Jusun, whose nickname is Chubai, one of the "Four Warriors of Buddha", modern four heads school in favor of classical prescriptions in Lingnan region. The now extant hand- written copy of this medical book is collected in the Shu Renzhi's Juxiang Hall in the early period of Republic of China. Analyses are made on the medical records of treating difficult and critical illness applied by Yi Jusun. The Shengma Biejia San (skunk bugbane and Carapax Amydae Powder) proposed by him played a vital role in preventing and curing plague in modern Guangdong Province.