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Birefringent crystals have important applications in optoelectronics areas due to their ability to modulate and polarize light. Despite increasing discovery of the birefringence potential of new crystals, it remains a great challenge to optimize both birefringence and bandgap simultaneously. Herein, a 1D chain-like hybrid perovskite birefringent crystal designed by 3D-to-1D dimensional tailoring, (GAM)2 PbI7 ·H2 O (GAM = C5 N10 H10 ), is presented, showing enlarged birefringence of 0.49@550 nm and enlarged optical bandgap (2.48 eV). Consequently, the birefringent quality factor of (GAM)2 PbI7 ·H2 O is up to 2.8 times that of the template MAPbI3 . In particular, the birefringence is much larger than those of commercial birefringent crystals and surpasses that of the vast majority of hybrid perovskite known to date. Theoretical calculations reveal that the strongly anisotropic arrangement of (GAM)2.5+ π-conjugated cations and ordered PbI6 octahedra contributes to the large birefringence and wide bandgap of (GAM)2 PbI7 ·H2 O. It is believed that this work will provide a new pathway toward the rational design and synthesis of hybrid perovskite birefringent crystals for compact wide-bandgap polarization dependent devices.
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In this study, lanthanum carbonate (LC) was selected as a capping agent to examine its effectiveness in immobilizing sediment internal phosphorus (P), arsenic (As) and tungsten (W). With a 180-day incubation experiment, it was determined that LC capping efficiently reduced the concentrations of soluble reactive P (SRP), soluble As and soluble W in pore water, with the highest reduction rate of 83.39%, 56.21% and 68.52%, respectively. The primary mechanisms involved in the adsorption of P, As and W by LC were precipitation reactions and ligand exchange. Additionally, P, As and W were immobilized by LC capping through the transformation of fractions from mobile and less stable forms to more stable forms. Furthermore, LC capping led to an increase in the Eh value, which promoted the oxidation of soluble Fe (â ¡) and soluble Mn. The significantly positive correlation and synchronized variations observed between SRP, soluble As, soluble W, and soluble Fe (II) indicated that the effects of LC on Fe redox played a crucial role in immobilizing sediment internal P, As and W. However, the oxidation of Mn, promoted by LC, played a more significant role in immobilizing sediment internal As than P and W. These effects resulted in LC capping achieving the highest reduction of SRP, soluble As and soluble W flux at 145.22, 22.19, and 0.58 µg m-2d-1. It is of note that LC capping did not lead to an elevated release hazard of Co, Ni, Cu, and Pb, barring Cd. Besides, LC capping did not modify the entire microbial communities in the sediment, but altered the proportional representation of specific microorganisms. Generally, LC has potential as a capping agent capable of simultaneously immobilizing sediment internal P, As and W.
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Arsénico , Lantano , Contaminantes Químicos del Agua , Contaminantes Químicos del Agua/análisis , Tungsteno , Fósforo , Sedimentos Geológicos , LagosRESUMEN
Lanthanum-modified bentonite (LMB) and calcium peroxide (CP) are known for their effective removal phosphorus (P) capacities. The present study aims to investigate the effects of the combined use of LMB and CPï¼LMB + CPï¼on the sediment P, dissolved organic matter (DOM) and iron (Fe) concentrations through a 90-day incubation experiment. The combined treatment showed strong removal effects on sediment P and DOM. Indeed, the SRP and DOM concentrations in the 0-10 cm sediment layer decreased following the combined application of LMB and CP by 40.67 and 28.95%, respectively, compared to those of the control group (CK). In contrast, the HCl-P in the 0-5 cm sediment layer increased following the combined treatment by 13.28%. In addition, compared with the single application of LMB, the LMB + CP treatment significantly reduced the soluble Fe (â ¡) in the sediment pore water and promoted the oxidation of Fe. Therefore, LMB + CP can enhance the removal of internal P from sediments. The DOM removal and Fe oxidation in sediment pore waters are beneficial for enhancing the adsorption of P by LMB. On the other hand, the single and combined applications of LMB and CP increased the richness of the sediment microbial communities while exhibiting slight effects on their diversity. According to the results of this study, the combined use of LMB and oxidizing materials represents a novel method for treating lakes with high internal phosphorus and DOM loads in sediments.
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Peróxidos , Fósforo , Contaminantes Químicos del Agua , Bentonita , Lantano , Lagos , Contaminantes Químicos del Agua/análisis , Materia Orgánica Disuelta , Sedimentos GeológicosRESUMEN
Ba1.09Pb0.91Be2(BO3)2F2 (BPBBF), a previously unreported lead-containing beryllium borate fluoride, has been successfully grown through a high-temperature flux method. Its structure is solved by single-crystal X-ray diffraction (SC-XRD), and it is optically characterized via infrared, Raman, UV-vis-IR transmission, and polarizing spectra as well. SC-XRD data suggests that it can be indexed by a trigonal unit cell (space group P3m1) with lattice parameters a = 4.7478(6) Å, c = 8.3856(12) Å, Z = 1, and V = 163.70(5) Å. This material could be considered as a derivative of the Sr2Be2B2O7 (SBBO) structural motif. It consists of 2D [Be3B3O6F3]∞ layers in the crystallographic ab plane, with divalent Ba2+ or Pb2+ cations serving as spacers among the adjacent layers. Ba and Pb were found to adopt a disordered arrangement in the trigonal prismatic coordination within the BPBBF structural lattice, which is evidenced by both structural refinements against SC-XRD data and energy dispersive spectroscopy. The UV absorption edge (279.1 nm) and birefringence (Δn = 0.054@ 546.1 nm) of BPBBF are confirmed by UV-vis-IR transmission and polarizing spectra, respectively. The discovery of this previous unreported SBBO-type material, BPBBF, along with other reported analogues such as BaMBe2(BO3)2F2 (M = Ca, Mg, and Cd), provide a prodigious example for tuning the bandgap, birefringence, and short UV absorption edge via simple chemical substitution.
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Submerged plants and lanthanum-modified bentonite (LMB) have important applications for the remediation of contaminated sediments; however, their combined effect on arsenic (As) removal has not been comprehensively evaluated. In this study, the physicochemical properties and changes in soluble As in sediments treated with LMB, Vallisneria spiralis (V. spiralis), and LMB + V. spiralis were observed at three time points (days 15, 35, and 66), and the changes in microbial and As species in sediments on day 66 were analyzed. LMB + V. spiralis treatment was the most effective for As removal. On day 66, the average concentrations of soluble As at a depth of 0-100 mm decreased by 12.71%, 48.81%, and 59.73% following treatment with LMB, V. spiralis, and LMB + V. spiralis, respectively. Further analysis showed that LMB is more effective at removing As(V) than V. spiralis, while V. spiralis is more effective at removing As(III), and the combination of LMB + V. spiralis is more effective for removing both As(III) and As(V) than individual LMB and V. spiralis treatments. LMB + V. spiralis enhanced the transformation of mobile As to Fe2O3/oxyhydroxide-bound As in sediments and the activity of As-oxidizing microorganisms. LMB promoted the growth of V. spiralis and enhanced the removal of As. This study indicates that this combination is an effective method for removing mobile As from sediments, and could effectively inhibit the release of As from sediments to overlying water.
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Arsénico , Hydrocharitaceae , Bentonita/química , Lantano/química , Sedimentos Geológicos/química , Fósforo/química , Lagos/químicaRESUMEN
In this study, CaO2 was used as a capping material to control the release of Phosphate (P) and tungsten (W) from the sediment due to its oxygen-releasing and oxidative properties. The results revealed significant decreases in SRP and soluble W concentrations after the addition of CaO2. The mechanisms of P and W adsorption by CaO2 were mainly chemisorption and ligand exchange mechanisms. In addition, the results showed significant increases in HCl-P and amorphous and poorly crystalline(oxyhydr)oxides bound W after the addition of CaO2. The highest reduction rates of sediment SRP and soluble W release were 37 and 43%, respectively. Furthermore, CaO2 can promote the redox of iron (Fe) and manganese (Mn). On the other hand, a significant positive correlation was observed between SRP/soluble W and soluble Fe (II) and between SRP/soluble W and soluble Mn, indicating that the effects of CaO2 on Fe and Mn redox play a crucial role in controlling P and W releases from sediments. However, the redox of Fe plays a key role in controlling sediment P and W release. Therefore, CaO2 addition can simultaneously inhibit sediment internal P and W release.
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Fósforo , Contaminantes Químicos del Agua , Tungsteno , Contaminantes Químicos del Agua/análisis , Sedimentos Geológicos , ManganesoRESUMEN
Common nonlinear optical (NLO) crystals consist of traditional functional building blocks with inherent optical limitation. Herein, inspired by traditional (B3 O6 )3- inorganic building block, we theoretically identified a new type of organic functional building blocks and then successfully synthesized the first cyamelurate NLO crystal, Ba(H2 C6 N7 O3 )2 â 8 H2 O. To our surprise, the constituent (H2 C6 N7 O3 )- building block is not in structurally optimal arrangement, but Ba(H2 C6 N7 O3 )2 â 8 H2 O exhibits excellent optical properties including wide band gap of 4.10â eV, very large birefringence of 0.24@550â nm, and exceptionally strong second-harmonic generation (SHG) response of about 12×KH2 PO4 . Both the SHG response and birefringence are much larger than those of commercial NLO crystal ß-BaB2 O4 with optimally aligned (B3 O6 )3- building block. Theoretical calculations suggest that the expanded π-conjugation delocalization within (H2 C6 N7 O3 )- vs (B3 O6 )3- should be responsible to the enhanced performance. This work implies that there is still much room to develop new NLO crystals with excellent functional building blocks that may be longly neglected.
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Birefringent crystals that can switch light polarization have important applications in optoelectronics. In the last decades, birefringence is mostly optimized by chemical strategies. Recently, switching birefringence by physical means has attracted much attention. Here, this work reports the observation of heat switching birefringence in a 2D layered hybrid halide perovskite (C2 N3 H4 )2 PbCl4 ((C2 N3 H4 )+ =1,2,4-triazolium). This heat switching birefringence leads to a significant change in the interference color for the crystal plate under the illumination of orthogonal polarized light. Structure analyses reveal a heat dependent structure transition in (C2 N3 H4 )2 PbCl4 , whose birefringence is switched by the change in the distortion degree of PbCl6 octahedron. This discovery may be beneficial to the further development of stimuli-responsive polarization optical devices.
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Antiperovskites have been studied since the 1980s because of their rich physical and chemical properties, but their linear and second-order nonlinear optical responses remain largely unknown. Here we report a new polar crystal, Cs3 Cl(HC3 N3 S3 ) (I), which features a quasi-one-dimensional antiperovskite structure composed of ClCs6 polyhedra and A-site [HC3 N3 S3 ]2- rings. To our best knowledge, this kind of antiperovskite structure is reported for the first time. Remarkably, I exhibits a very strong nonlinear optical response up to 11.4 times that of the benchmark KH2 PO4 and exceptionally large birefringence of 0.52. The first-principles calculations and structural analyses reveal that [HC3 N3 S3 ]2- is the "material gene" while the antiperovskite structural feature making it in a favorable arrangement. This work provides a new structural platform for the rational design of integrated optoelectronic materials with linear and second-order nonlinear optical responses.
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Birefringent materials are highly demanded for high-performance polarized optics. As compared with artificial anisotropic metamaterials, anisotropic crystals have advantages of low optical losses and easy processing, but their birefringence is still limited. Herein, based on first-principles studies, we identified a new type of functional anion units, (Hx C6 N9 )(3-x)- (x=0, 1, 2), and then successfully synthesized a new anisotropic crystal, namely, CsH2 C6 N9 â H2 O (I), whose crystal structure consists of (H2 C6 N9 )- anions. Remarkably, I is ultraviolet transparent and exhibits very large birefringence of about 0.55@550â nm, which is much larger than those of commercial birefringent crystals. These results make I a candidate for highly efficient manipulation of optics and light in optical modulation devices. Theoretical calculations reveal that large birefringence mainly arises from the cooperative π orbitals in (H2 C6 N9 )- anions. This work provides a new insight on the underlying structure-property relationships of anisotropic crystals.
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In our study, we aimed to assess the long-term risk of gastric cardia adenocarcinoma (GCA) for patients with different histological cardia lesions to inform future guidelines for GCA screening in China. We conducted a population-based prospective study among 9740 subjects who underwent upper endoscopy screening during 2005 to 2009 and followed until December 2017. Cumulative incidence and mortality rates of GCA were calculated by the baseline histological diagnoses, and the hazard ratios (HRs), overall and by age and sex, were analyzed by Cox proportional hazards models. During a median follow-up of 10 years, we identified 123 new GCA cases (1.26%) and 31 GCA deaths (0.32%). The age-standardized incidence and mortality rates of GCA were 128.71/100 000 and 35.69/100 000 person-years, and cumulative incidence rate in patients with cardia high-grade dysplasia (CHGD), cardia low-grade dysplasia (CLGD) and atrophic carditis (AC)/cardia intestinal metaplasia (CIM) was 25%, 3.05% and 1.58%, respectively. The progression rate and cancer risk of GCA increased monotonically with each step in Correa's cascade. Individuals aged 50 to 69 years had 4.4 times higher GCA incidence than those aged 40 to 49 years. Patients with CLGD had a significantly higher 3-year GCA incidence than the normal group, while patients with AC/CIM had a comparable GCA risk during 3-year follow-up but a higher risk at 5-year intervals. Our results suggested a postponed starting age of 50 years for GCA screening, immediate treatment for patients with CHGD, a 3-year surveillance interval for patients with CLGD, and a lengthened surveillance interval of 5 years for patients with AC/CIM.
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Adenocarcinoma/diagnóstico , Cardias/patología , Vigilancia de la Población/métodos , Lesiones Precancerosas/diagnóstico , Neoplasias Gástricas/diagnóstico , Adenocarcinoma/etnología , Adulto , Factores de Edad , Anciano , Pueblo Asiatico/estadística & datos numéricos , China/epidemiología , Femenino , Humanos , Incidencia , Masculino , Persona de Mediana Edad , Lesiones Precancerosas/etnología , Modelos de Riesgos Proporcionales , Estudios Prospectivos , Factores de Riesgo , Neoplasias Gástricas/etnología , Análisis de SupervivenciaRESUMEN
Discovering new functional genes and developing high-performance materials are the goals being pursued by scientists. In this work, we successfully obtained a second-order nonlinear optical (NLO) material via the aqueous solution method, Y[N(CN)2 ]4 [NH(C2 H5 )3 ] â 3H2 O, which is the first NLO material with the anionic group N(CN)2 - . Remarkably, this material is not only strongly NLO-active at 1064â nm with a response of about 2.8 × KH2 PO4 , but also possesses a short UV absorption edge of 250â nm. In-depth first-principles calculations illustrate well that the optical properties are mainly from the strong interaction of N, C and Y atoms. This result indicates that the N(CN)2 - anion may be a new NLO functional gene. This work enriches the diversity of NLO functional genes and materials.
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AnionesRESUMEN
OBJECTIVE: To summarize the colorectal cancer (CRC) burden and trend in the world, and compare the difference of CRC burden between other countries and China. METHODS: Incidence and mortality data were extracted from the GLOBOCAN2018 and Cancer Incidence in Five Continents. Age-specific incidence trend was conducted by Joinpoint analysis and average annual percent changes were calculated. RESULTS: About 1.85 million new cases and 0.88 million deaths were expected in 2018 worldwide, including 0.52 million (28.20%) new cases and 0.25 million (28.11%) deaths in China. Hungary had the highest age-standardized incidence and mortality rates in the world, while for China, the incidence and mortality rates were only half of that. CRC incidence and mortality were highly correlated with human development index (HDI). Unlike the rapid increase in Republic of Korea and the downward trend in Canada and Australia, the age-standardized incidence rates by world standard population in China and Norway were rising gradually. The age-specific incidence rate in the age group of 50-59 years in China was increasing rapidly, while in Republic of Korea and Canada, the fastest growing age group was 30-39 years. CONCLUSIONS: The variations of CRC burden reflect the difference of risk factors, as well as levels of HDI and screening (early detection activities). The burden of CRC in China is high, and the incidence of CRC continues to increase, which may lead to a sustained increase in the burden of CRC in China in the future. Screening should be expanded to control CRC, and focused on young people in China.
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OBJECTIVE: Esophageal squamous cell carcinoma (ESCC) is one of the dominant malignances worldwide, but currently there is less focus on the microbiota with ESCC and its precancerous lesions. METHODS: Paired esophageal biopsy and swab specimens were obtained from 236 participants in Linzhou, China. Data from 16S ribosomal RNA gene sequencing were processed using quantitative insights into microbial ecology (QIIME2) and R Studio to evaluate differences. The Wilcoxon rank sum test and Kruskal-Wallis rank sum test were used to compare diversity and characteristic genera by specimens and participant groups. Ordinal logistic regression model was used to build microbiol prediction model. RESULTS: Microbial diversity was similar between biopsy and swab specimens, including operational taxonomic unit (OTU) numbers and Shannon index. There were variations and similarities of esophageal microbiota among different pathological characteristics of ESCC. Top 10 relative abundance genera in all groups include Streptococcus, Prevotella, Veillonella, Actinobacillus, Haemophilus, Neisseria, Alloprevotella, Rothia, Gemella and Porphyromonas. Genus Streptococcus, Haemophilus, Neisseria and Porphyromonas showed significantly difference in disease groups when compared to normal control, whereas Streptococcus showed an increasing tendency with the progression of ESCC and others showed a decreasing tendency. About models based on all combinations of characteristic genera, only taken Streptococcus and Neisseria into model, the prediction performance was the ideal one, of which the area under the curve (AUC) was 0.738. CONCLUSIONS: Esophageal biopsy and swab specimens could yield similar microbial characterization. The combination of Streptococcus and Neisseria has the potential to predict the progression of ESCC, which is needed to confirm by large-scale, prospective cohort studies.
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Arsenic (As) is a metalloid that can accumulate in eutrophic lakes and cause adverse health effects to people worldwide. However, the seasonal process and dynamic mechanism for As mobilization in eutrophic lake remains effectively unknown. Here we innovatively used the planar optodes (PO), high-resolution dialysis (HR-Peeper) combined with fluorescence excitation-emission matrix coupled with parallel factor (EEM-PARAFAC) analysis technologies. We synchronously investigate monthly O2, As, iron (Fe), manganese (Mn), and naturally occurring dissolved organic matter (DOM) changes in sediments of Lake Taihu at high resolution in field conditions. We find high As contamination from sediments with 61.88-327.07 µg m-2 d-1 release As fluxes during the algal bloom seasons from May to October 2021. Our results show that an increase in DOM, mainly for humic-like components, resulting in high electron transfer capacity (ETC), promoted the reductive dissolution of Fe and Mn oxides to release As. Partial least square-path modeling (PLS-PM) and random forest modeling analysis identified that Mn oxide reductive dissolution directly accelerated sediments As contamination, which is the crucial factor. Understanding crucial factor controlling As release is especially essential in areas of eutrophic lakes developing effective strategies to manage As-rich eutrophic lake sediments worldwide.
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Arsénico , Manganeso , Humanos , Materia Orgánica Disuelta , Hierro , LagosRESUMEN
BACKGROUND: Microbiota may be associated with esophageal squamous cell carcinoma (ESCC) development. However, it is not known the predictive value of microbial biomarkers combining epidemiological factors for the early detection of ESCC and precancerous lesions. METHODS: A total of 449 specimens (esophageal swabs and saliva) were collected from 349 participants with different esophageal statuses in China to explore and validate ESCC-associated microbial biomarkers from genes level to species level by 16S rRNA sequencing, metagenomic sequencing and real-time quantitative polymerase chain reaction. RESULTS: A bacterial biomarker panel including Actinomyces graevenitzii (A.g_1, A.g_2, A.g_3, A.g_4), Fusobacteria nucleatum (F.n_1, F.n_2, F.n_3), Haemophilus haemolyticus (H.h_1), Porphyromonas gingivalis (P.g_1, P.g_2, P.g_3) and Streptococcus australis (S.a_1) was explored by metagenomic sequencing to early detect the participants in Need group (low-grade intraepithelial neoplasia, high-grade intraepithelial neoplasia and ESCC) vs participants without these lesions as the Noneed group. Significant quantitative differences existed for each microbial target in which the detection efficiency rate was higher in saliva than esophageal swab. In saliva, the area under the curve (AUC) based on the microbial biomarkers (A.g_4 â© P.g_3 â© H.h_1 â© S.a_1 â© F.n_2) was 0.722 (95% CI 0.621-0.823) in the exploration cohort. Combining epidemiological factors (age, smoking, drinking, intake of high-temperature food and toothache), the AUC improved to 0.869 (95% CI 0.802-0.937) in the exploration cohort, which was validated with AUC of 0.757 (95% CI 0.663-0.852) in the validation cohort. CONCLUSIONS: It is feasible to combine microbial biomarkers in saliva and epidemiological factors to early detect ESCC and precancerous lesions in China.
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Detección Precoz del Cáncer , Neoplasias Esofágicas , Carcinoma de Células Escamosas de Esófago , Lesiones Precancerosas , Humanos , Neoplasias Esofágicas/diagnóstico , Neoplasias Esofágicas/epidemiología , Neoplasias Esofágicas/microbiología , Masculino , Femenino , Persona de Mediana Edad , Lesiones Precancerosas/diagnóstico , Lesiones Precancerosas/microbiología , China/epidemiología , Carcinoma de Células Escamosas de Esófago/diagnóstico , Carcinoma de Células Escamosas de Esófago/epidemiología , Carcinoma de Células Escamosas de Esófago/microbiología , Detección Precoz del Cáncer/métodos , Anciano , Saliva/microbiología , ARN Ribosómico 16S/genética , Microbiota , Biomarcadores de Tumor , Adulto , Metagenómica/métodos , Valor Predictivo de las PruebasRESUMEN
Sulfate concentrations in eutrophic waters continue to increase; however, the transformations of arsenic (As) in sediments under these conditions are unclear. In this study, we constructed a series of microcosms to investigate the effect of algal degradation on As transformations in sediments with high sulfate concentrations. The results showed that both the elevated sulfate levels and algal degradation enhanced the release of As from sediments to the overlying water, and degradation of algal in the presence of elevated sulfate levels could further contribute to As release. Sulfate competed with arsenate for adsorption in the sediments, leading to As desorption, while algal degradation created a strongly anaerobic environment, leading to the loss of the redox layer in the surface sediments. With high sulfate, algal degradation enhanced sulfate reduction, and sulfur caused the formation of thioarsenates, which may cause re-dissolution of the arsenides, enhancing As mobility by changing the As speciation. The results of sedimentary As speciation analysis indicated that elevated sulfur levels and algal degradation led to a shift of As from Fe2O3/oxyhydroxide-bound state to specifically adsorbed state at the sediment water interface. This study indicated that algal degradation increases the risk of As pollution in sulfate-enriched eutrophic waters.
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Arsénico , Contaminantes Químicos del Agua , Arsénico/análisis , Sulfatos/análisis , Agua/análisis , Oxidación-Reducción , Óxidos de Azufre , Azufre , Sedimentos Geológicos/análisis , Contaminantes Químicos del Agua/análisisRESUMEN
Polyaluminum chloride (PAC) is a traditional material used for immobilizing sediment internal phosphorus (P) in field-scale experiment. Lanthanum carbonate (LC) is an emerging material which have been used in immobilizing sediment internal P in laboratory. To promote LC in practice, the premise is that it does have advantages over traditional material when used. Herein, a 90-day incubation experiment was conducted comparing the effectiveness and mechanism of LC and PAC capping in controlling sediment internal P. The results of isotherm experiment and XPS analysis indicated that the adsorption mechanism of P onto LC and PAC involved ligand exchange and formation of inner-sphere La/Al-O-P complexes. The incubation experiment revealed that PAC capping was more effective in reducing pore water soluble reactive phosphorus (SRP), exhibiting a reduction of up to 81.32 % but showed a decrease trend. However, LC capping resulted in a reduction of pore water SRP up to 52.84 % and maintained stability. On average, LC and PAC capping reduced SRP flux by 0.27 and 0.32 µg·m-2d-1, respectively relative to the control sediment. Moreover, LC capping facilitated the formation of Fe(III)/Mn(IV) oxyhydroxides, leading to an increased P adsorption, whereas PAC capping facilitated the reduction of Fe(III)/Mn(IV) minerals with P release. Additionally, LC capping resulted in the reduction of a higher ratio of mobile P/TP to stable P forms than PAC capping, as compared to the control. In contrast to PAC capping which converted mobile P to stable NaOH-rP, LC capping transformed mobile P and NaOH-rP into more stable HCl-P and ResP. Both LC and PAC capping caused variations in sediment bacterial communities. Nevertheless, PAC capping heightened the risk of Co, Ni, Cu, and Pb releases in sediment compared to LC capping. In summary, this study suggested that LC capping surpassed PAC capping in immobilizing sediment internal P.
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It is well known that aquaculture can alter the microenvironments of lakes at sediment-water interface (SWI). However, the main mechanisms underlying the effects of aquaculture activities on arsenic (As) transformations are still unclear. In this context, the present study aims to investigate the variations in the sediment As contents in Yangcheng Lake, as well as to assess its chemical transformations, release fluxes, and release mechanisms. The results showed substantial spatial differences in the dissolved As concentrations in the sediment pore water. The As release fluxes at the SWI ranged from 1.32 to 112.09 µg/L, with an average value of 33.68 µg/L. In addition, the highest As fluxes were observed in the aquaculture areas. The transformation of crystalline hydrous Fe oxide-bound As to adsorbed-As in the aquaculture lake sediments increased the ability of As release. The Partial least squares path modeling results demonstrated the great contributions of organic matter (OM) to the As transformations by influencing the sediment microbial communities and Fe/Mn minerals. The changes in the As fractionation and competing adsorption increased the dissolved As concentrations in the 0-10 mm surface sediment. Non-specifically and specifically adsorbed As were the major sources of dissolved As in the sediments. Specifically, microbial reduction of As[V] and dissolution of Fe oxides increased the dissolved As concentrations at the SWI (20 to -20 mm). The results of the current study highlight the positive enhancement effects of aquaculture on As release from sediments.
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Acuicultura , Arsénico , Sedimentos Geológicos , Lagos , Contaminantes Químicos del Agua , Sedimentos Geológicos/química , Arsénico/análisis , Arsénico/química , Lagos/química , Contaminantes Químicos del Agua/análisis , Contaminantes Químicos del Agua/química , Monitoreo del Ambiente , AdsorciónRESUMEN
Fluoroquinolones (FQ) are essential for the treatment of multidrug-resistant tuberculosis (MDR-TB). The FQ resistance (FQ-R) rate in MDR-TB in China and its risk factors remain poorly understood. We conducted a retrospective, population-based genomic epidemiology study of MDR-TB patients in Shanghai, China, from 2009 to 2018. A genomic cluster was defined as strains with genetic distances ≤ 12 single nucleotide polymorphisms. The transmitted FQ-R was defined as the same FQ resistance-conferring mutations shared by ≥ 2 strains in a genomic cluster. We used multivariable logistic regression analysis to identify the risk factors for drug resistance. Among the total 850 MDR-TB patients included in the study, 72.8% (619/850) were male, the median age was 39 (interquartile range 28, 55) years, 52.7% (448/850) were migrants, and 34.5% (293/850) were previously treated patients. Most of the MDR-TB strains belong to the Beijing lineage (91.7%, 779/850). Overall, the genotypic resistance rate of FQ was 34.7% (295/850), and 47.1% (139/295) FQ-R patients were in genomic clusters, of which 98 (33.2%, 98/295) were presumed as transmitted FQ-R. Patients with treatment-naïve (aOR = 1.84; 95% CI: 1.09, 3.16), diagnosed in a district-level hospital (aOR = 2.69; 95% CI: 1.56, 4.75), and streptomycin resistance (aOR = 3.69; 95% CI: 1.65, 9.42) were significantly associated with the transmission of FQ-R. In summary, the prevalence of FQ-R among MDR-TB patients was high in Shanghai, and at least one-third were transmitted. Enforced interventions including surveillance of FQ drug susceptibility testing and screening among MDR-TB before initiation of treatment were urgently needed.