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1.
Zhongguo Shi Yan Xue Ye Xue Za Zhi ; 29(1): 26-31, 2021 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-33554792

RESUMO

OBJECTIVE: To explore the synergistic immunomodulatory mechanism of interferon alpha-1b, interleukin-2 and thalidomide (ITI) regimen on patients with acute myeloid leukemia (AML). METHODS: Sixty eight untreated de novo or relapsed or refractory or maintenance therapy patients with AML admitted in the Affiliated Cancer Hospital of Zhengzhou University and the other 11 medical units from March 2016 to May 2019 were treated with ITI regimen. Peripheral blood specimen per patient was collected into EDTA-K3 anticoagulation vacuum tube before the administration of ITI and 3 months after the treatment; peripheral blood lymphocyte subsets and perforin and Granzyme B expression were analyzed by using flow cytometry; the levels of VEGF, IFN-γ, TNF-α and IL-6 in the plasma were detected by using a cytometric bead array. Thirty-five healthy subjects from the hospital physical examination centre were selected as normal controls. RESULTS: The ratio of CD4+/CD8+ T cells, the percentage of NK cells, the expression of perforin and Granzyme B of NK cells in the peripheral blood of patients with hematological malignancies were lower than those of healthy controls. The level of VEGF, IL-6 and TNF-α in the peripheral plasma were higher than those of the healthy control group, and the difference was statistically significant. The level of IFN-γ was lower, and the difference was not statistically significant. The ratio of CD4+/CD8+ T cells, the percentage of NK cells, the expression of Granzyme B and Perforin of NK cells in peripheral blood were higher after the therapy of thalidomide combined with rhIFNα-1b for 3 months as compared with those before treatment of ITI, the level of the IFN-γ in peripheral plasma was higher while that of VEGF was lower, the difference was statistically significant; after treatment, the ratio of CD3+ CD4+ and CD3+ CD8+ lymphocytes and the level of TNF-α in peripheral blood were higher those that before treatment, IL-6 was lower, while the difference was not statistically significant. CONCLUSION: The ITI regimen can raise the ratio of CD4+/CD8+ T cells and the percentage of natural killer cells, also, can enhance the generation of perforin and granzyme B and the concentration of IFN-γ as well as inhibit the generation of VEGF, suggesting that these activities may enhance the antitumour capacity of patients with AML.


Assuntos
Interleucina-2 , Leucemia Mieloide Aguda , Linfócitos T CD8-Positivos , Humanos , Interferon-alfa , Leucemia Mieloide Aguda/tratamento farmacológico , Perforina , Talidomida
2.
Artigo em Inglês | MEDLINE | ID: mdl-33491127

RESUMO

Based on a typical residential area, this paper studies the characteristics of pollutant concentration changes in two rainfall runoffs and the first flush effect of rainfall. In rainfall runoff, the concentrations of seven pollutants (CODMn, TN, DTN, NH3-N, TP, DTP, and PO43-) increased during the initial rainfall period and decreased in the later period. Rainfall causes the erosion of pollutants on the underlying surface so that water pollution begins when rainfall runoff occurs, and the pollution level drops over time. The seven pollutants all experience this first flush effect, of which, rainfall has the strongest scouring effect on NH3-N produced by domestic sewage. The significant excess of pollutants in rainfall runoff should be considered by management departments. In addition, the existence of the first flush effect makes it possible in theory to partially intercept rainfall runoff to control water pollution, thereby reducing the cost of pollution control.

3.
Ecotoxicol Environ Saf ; 208: 111720, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33396051

RESUMO

Fine particulate matter (PM2.5), a ubiquitous environmental pollutant, has been indicated to affect thyroid hormone (TH) homeostasis in women, but the detailed mechanism behind this effect remains unclear. The objective of this study was to evaluate the roles of the hypothalamic-pituitary-thyroid (HPT) axis and hepatic transthyretin in the thyroid-disrupting effects of PM2.5. Sprague Dawley rats were treated with PM2.5 (0, 15 and 30 mg/kg) by passive pulmonary inhalation for 49 days; and recovery experimental group rats were dosed with PM2.5 (30 mg/kg) for 35 days, and no treatment was done during the subsequent 14 days. PM2.5 was handled twice a day by passive pulmonary inhalation throughout the study. After treatment, pathological changes were analyzed by performing haemotoxylin and eosin staining, measuring levels of THs and urine iodine (UI) in serum, plasma, and urine samples using enzyme-linked immunoabsorbent assay, and expression of proteins in the hypothalamus, pituitary, thyroid, and liver tissues of rats were analyzed by immunohistochemistry and Western blotting. The levels of oxidative stress factors, such as reactive oxygen species (ROS), malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (Gpx), and nuclear factor-kappa B (NF-κB) in female rats' plasma were also evaluated by ELISA. The results of these analyses revealed that PM2.5 treatment induced pathologic changes in rat thyroid and liver characterized by increased follicular cavity size and decreased amounts of follicular epithelial cells and fat vacuoles, respectively. Serum levels of triiodothyronine, thyroxine, and thyroid stimulating hormone were significantly decreased, plasma NF-κB level was increased and plasma redox state was unbalanced (enhanced ROS, MDA and Gpx levels; reduced SOD activities) in female rats treated with PM2.5 (P < 0.05). PM2.5 treatment suppressed the biosynthesis and biotransformation of THs by increasing sodium iodide symporter, thyroid transcription factor 1, thyroid transcription factor 2, and paired box 8 protein expression levels (P < 0.05). Additionally, thyroid stimulating hormone receptor and thyroid peroxidase levels were significantly decreased (P < 0.05). Both thyrotropin releasing hormone receptor and thyroid stimulating hormone beta levels were enhanced (P < 0.05). Moreover, transport of THs was inhibited due to reduced protein expression of hepatic transthyretin upon treatment with PM2.5. In summary, PM2.5 treatment could perturb TH homeostasis by affecting TH biosynthesis, biotransformation, and transport, affecting TH receptor levels, and inducing oxidative stress and inflammatory responses. Activation of the HPT axis and altered hepatic transthyretin levels therefore appear to play a crucial role in PM2.5-induced thyroid dysfunction.


Assuntos
Sistema Hipotálamo-Hipofisário/efeitos dos fármacos , Material Particulado/toxicidade , Pré-Albumina/metabolismo , Glândula Tireoide/efeitos dos fármacos , Hormônios Tireóideos/metabolismo , Animais , Feminino , Homeostase/efeitos dos fármacos , Sistema Hipotálamo-Hipofisário/metabolismo , Fígado/efeitos dos fármacos , Fígado/metabolismo , Fígado/patologia , Estresse Oxidativo/efeitos dos fármacos , Tamanho da Partícula , Material Particulado/química , Ratos , Ratos Sprague-Dawley , Receptores dos Hormônios Tireóideos/metabolismo , Glândula Tireoide/metabolismo , Glândula Tireoide/patologia
4.
Artigo em Inglês | MEDLINE | ID: mdl-33106903

RESUMO

Inland freshwater lakes have been widely considered as significant sources of CO2 to the atmosphere. However, long-term measurements of CO2 dynamics in lakes are still lacking, but are necessary due to their large temporal variations. Herein, we present the long-term dynamics of water parameters in Lake Donghu from 2002 to 2016, and further calculate the partial pressure of CO2 (pCO2) based on the measurements of pH, water temperature, and alkalinity from 2008 to 2016. The results revealed that a significantly high pCO2 occurred during the winter in Lake Donghu (p < 0.01), whereas no significant spatial difference was observed (p = 0.37). Statistical analysis indicated that the pCO2 in the lake was only positively correlated with the total phosphorus (TP) concentration (p < 0.05). A multilinear regression model provided the best predictors for the pCO2; however, it only explained 16% of the observed pCO2 variability. This indicates the complex factors that influenced the pCO2 in Lake Donghu between 2008 and 2016. Our estimated CO2 flux revealed that Lake Donghu acted as a small CO2 source to the atmosphere during this period, with a mean CO2 flux of 10.8 ± 37.4 mg m-2 day-1 corresponding to a mean CO2 emission of 0.13 ± 0.43 Gg year-1. The CO2 emission fluxes in Lake Donghu were much lower than the mean CO2 fluxes reported for other lakes in China and globally. Furthermore, the long-term evolution of the CO2 flux indicated that Lake Donghu has shifted between acting as a CO2 source and sink, which highlights the need for long-term monitoring to accurately evaluate CO2 emissions from lakes.

5.
Food Chem ; : 128243, 2020 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-33069529

RESUMO

Tea saponins from Camellia oleifera Abel. seed pomace are new sources of commercial saponins. This study established an eco-friendly and efficient extraction method for tea saponins from C. oleifera seed pomace. A ternary deep eutectic solvent (DES) composed of l-proline, glycerol and sucrose (4:10:1 in molar ratio, abbreviated as PGS-5) achieved the highest extraction yield of tea saponins among all screened DESs. A maximum extraction yield of 23.22 ± 0.28% was obtained using PGS-5 under the optimized extraction time, DES concentration and liquid-solid ratio. Through ultraviolet, Fourier transform infrared spectroscopy and ultrahigh-performance liquid chromatography-Q Exactive HF mass spectroscopy, as well as analyses of antioxidant and antimicrobial activities, it was determined that extracted saponins did not altered during processing. Therefore, PGS-5 can serve as a solvent to obtain stable and beneficial tea saponins from C. oleifera seed pomace.

6.
Bioorg Chem ; 100: 103923, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32417525

RESUMO

Given the important role of biothiols in various physiological processes, there is a need to develop novel fluorescent sensors for detecting them. Herein, a novel "on-off-on" fluorescent sensor (E)-N'-((7-(diethylamino)-2-oxo-2H-chromen-3-yl)methylene)-6-((quinolin-8-yloxy)methyl)picolinohydrazide (PQC) was synthesized and its absorbance and fluorescence properties were characterized. The sensor PQC could form a stable complex and showed a significant fluorescence quenching response to Cu2+ with a quenching efficiency of approximately 100%, and the PQC-Cu2+ complex showed a fluorescence enhancement response to GSH with a higher recovery rate of above 80% in a CH3OH/HEPES (9:1 v/v, pH = 7.23) buffer system. Its detection limits were determined to be 0.17 µM for Cu2+ and 0.20 µM for GSH, and the binding stoichiometry of PQC-Cu2+ was determined to be 1: 1 by Job's plot method. Importantly, the sensor PQC can be used for filter paper strip tests and bioimaging in living cells.

7.
Food Sci Nutr ; 8(2): 1284-1294, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32148834

RESUMO

Mango (Mangifera indica L.) is respiratory climacteric fruit that ripens and decomposes quickly following their harvest. 1-methylcyclopropene (1-MCP) is known to affect the ripening of fruit, delaying the decay of mango stored under ambient conditions. The objective of this study was to clarify the role of 1-MCP in the regulation of ethylene biosynthesis and ethylene receptor gene expression in mango. 1-MCP significantly inhibited the 1-aminocyclopropane-1-carboxylic acid (ACC) content. The activity of ACC oxidase (ACO) increased on days 6, 8, and 10 of storage, whereas delayed ACC synthase (ACS) activity increased after day 4. The two homologous ethylene receptor genes, ETR1 and ERS1 (i.e., MiETR1 and MiERS1), were obtained and deposited in GenBank® (National Center for Biotechnology Information-National Institutes of Health [NCBI-NIH]) (KY002681 and KY002682). The MiETR1 coding sequence was 2,220 bp and encoded 739 amino acids (aa). The MiERS1 coding sequence was 1,890 bp and encoded 629 aa, similar to ERS1 in other fruit. The tertiary structures of MiETR1 and MiERS1 were also predicted. MiERS1 lacks a receiver domain and shares a low homology with MiETR1 (44%). The expression of MiETR1 and MiERS1 mRNA was upregulated as the storage duration extended and reached the peak expression on day 6. Treatment with 1-MCP significantly reduced the expression of MiETR1 on days 4, 6, and 10 and inhibited the expression of MiETR1 on days 2, 4, 6, and 10. These results indicated that MiETR1 and MiERS1 had important functions in ethylene signal transduction. Treatment with 1-MCP might effectively prevent the biosynthesis of ethylene, as well as ethylene-induced ripening and senescence. This study presents an innovative method for prolonging the storage life of mango after their harvest through the regulation of MiETR1 and MiERS1 expression.

8.
Spectrochim Acta A Mol Biomol Spectrosc ; 230: 118022, 2020 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-31927510

RESUMO

In this study, a highly selective fluorescent sensor (E)-2-((2-(benzo[d]thiazol-2-yl)quinolin-8-yl)oxy)-N'-((7-(diethylamino)-2-oxo-2H-chromen-3-yl)methylene)acetohydrazide (TQC) was synthesized from 2-methylquinolin-8-ol and 4-(diethylamino)-2-hydroxybenzaldehyde and its structure was characterized by 1H NMR, 13C NMR, ESI-HR-MS and density functional theory (DFT) calculation. Sensor TQC showed an obvious "on-off-on" fluorescence response to Cu2+ and PPi in a DMSO/HEPES (3:2 v/v, pH = 7.4) buffer system. The detection limits of sensor TQC were 0.06 µM to Cu2+ and 0.01 µM to PPi. In addition, sensor TQC showed a 1:1 binding stoichiometry to Cu2+ and TQC-Cu2+ complex showed a 2:1 binding stoichiometry to PPi. The optimum pH range of sensor TQC and TQC-Cu2+ was 3-8. Further studies demonstrated that sensor TQC could be made into test paper strips for the qualitative of Cu2+ and PPi and showed sequentially "on-off-on" fluorescent bio-imaging of Cu2+ and PPi in HeLa cells.


Assuntos
Benzotiazóis/química , Cobre/análise , Cumarínicos/química , Difosfatos/análise , Corantes Fluorescentes/química , Cátions Bivalentes/análise , Células HeLa , Humanos , Microscopia de Fluorescência , Modelos Moleculares , Imagem Óptica , Espectrometria de Fluorescência
9.
J Phys Chem Lett ; 11(3): 993-999, 2020 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-31952442

RESUMO

The thermal quenching behavior (temperature-dependent luminescence) has severely hindered the practical applications of CsPbX3 nanocrystals. Here, we find that a simple surface treatment using ammonium hexafluorosilicate (AHFS, (NH4)2SiF6) can drastically reduce the thermal quenching of CsPbBr3 nanocrystals (CPB-NCs) while enhancing their photostability. The AHFS-treated sample sustains 90% of its original emission intensity as the temperature rises to 353 K, which is much better than that (17%) of the pristine sample. Meanwhile, the thermally stable AHFS-treated sample could maintain 93% of its initial PL emission after a 450 nm LED illumination of 53 h. Structural and surface characterizations indicate that the hydrolyzable AHFS absorbed on the surface could lead to a bifunctional passivation for CPB-NCs, through fluoride ions and its hydrolyzed product of silica, which can reduce the thermal quenching by limiting thermally activated carriers trapping into vacancies and block the attack from external environmental factors.

10.
Nat Commun ; 11(1): 31, 2020 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-31911597

RESUMO

Achieving good stability while maintaining excellent properties is one of the main challenges for enhancing the competitiveness of luminescent perovskite CsPbX3 (X=Cl, Br, I) nanocrystals (NCs). Here, we propose a facile strategy to synthesize ceramic-like stable and highly luminescent CsPbBr3 NCs by encapsulating them into silica derived from molecular sieve templates at high temperature (600-900 oC). The obtained CsPbBr3-SiO2 powders not only show high photoluminescence quantum yield (~71%), but also show an exceptional stability comparable to the ceramic Sr2SiO4:Eu2+ green phosphor. They can maintain 100% of their photoluminescence value under illumination on blue light-emitting diodes (LEDs) chips (20 mA, 2.7 V) for 1000 h, and can also survive in a harsh hydrochloric acid aqueous solution (1 M) for 50 days. We believe that the above robust stabilities will significantly enhance the potential of perovskite CsPbX3 NCs to be practically applied in LEDs and backlight displays.

11.
Sci Total Environ ; 698: 134328, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31783469

RESUMO

In eutrophic lacustrine ecosystems, drifting algal blooms are easily trapped by emergent macrophytes in downwind littoral zones, potentially altering carbon cycling processes; yet, knowledge remains limited about the mechanisms driving these changes. In this study, Microcystis and Phragmites, two dominant photosynthetic organisms in a hypereutrophic (Lake Taihu, China), were collected to simulate their co-decomposition processes. We demonstrate how molecular-level biomarkers could be used to elucidate the degradation dynamics of these two distinct organic forms in mixtures. Microcystis-derived carbon accelerated the decomposition rate of mixed systems (positive co-metabolism effect), rather than retarding it. The decomposition rate of TOC (total organic carbon) directly measured in the mixed treatments was 14% higher than when the two substrates were incubated alone. The use of specific fatty acid biomarkers facilitated more accurate tracking, demonstrating 1.09 times higher decomposition rates for Phragmites detritus in mixed treatments than in single Phragmites treatments. Furthermore, Microcystis showed 0.98 times higher decomposition rates in mixed treatments than in single treatments. The addition of Microcystis detritus to Phragmites detritus might meet microbial stoichiometric requirements, increasing the abundance of decomposing bacteria in Phragmites detritus, and accelerating decomposition rates, resulting in the co-metabolism of Microcystis and Phragmites carbon. Given the increasing occurrence of algal blooms in eutrophic lakes, the processes documented here might enhance greenhouse gas emissions from lakes with continued global climate warming.


Assuntos
Monitoramento Ambiental , Lagos/química , Poluentes da Água/análise , Biomarcadores , China , Ecossistema , Eutrofização , Sedimentos Geológicos , Microcystis
12.
J Fluoresc ; 29(6): 1423-1429, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31758369

RESUMO

In this study, a BODIPY-based water-soluble fluorescent chemosensor BBP has been synthesized using BODIPY as the fluorescence group and quinoline as the recognition group. BBP can be used for naked eye detection of pH in complete aqueous solution and it shows high specificity in a wide range of cations. The pKa value is determined to be 2.94 and the fluorescence intensity is linearly related to pH in the range of 2.4-3.6.

13.
Cancer Biomark ; 26(3): 353-360, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31524144

RESUMO

Aberrant expression of miR-181d has been noted in multiple human cancers, but its role in gastric cancer (GC) remains unclear. The aim of this study was to investigate the expression, clinical significance and functional role of miR-181d in GC. We applied quantitative real-time polymerase chain reaction (qRT-PCR) to quantify the expression of miR-181d in 131 GC tissues, as well as in GC cell lines. The correlation of miR-181d expression with overall survival of GC patients was analyzed using the Kaplan-Meier survival method. Cox regression analysis was conducted to further determine the prognostic value of miR-181d in GC. Cellular functional experiments were carried out to calculate the effect that miR-181d had on GC behaviors. MiR-181d expression was significantly up-regulated in both GC tissues and cells (all P< 0.001), and correlated with TNM stage and lymph node metastasis (all P< 0.05). GC patients in the high miR-181d expression group had shorter survival time than those in the low miR-181d expression group (log-rank P< 0.001). Multivariate Cox regression analysis demonstrated that miR-181d expression and TNM stage were two independent prognostic markers for GC. Overexpression of miR-181d significantly promoted the NCI-N87 and MGC-803 cells proliferation, migration and invasion (all P< 0.05). MiR-181d serves a role as an oncogene in GC by promoting tumor progression. And miR-181d might be a novel predictive marker for the prognosis of GC patients.


Assuntos
Biomarcadores Tumorais/metabolismo , MicroRNAs/metabolismo , Neoplasias Gástricas/genética , Biomarcadores Tumorais/isolamento & purificação , Movimento Celular/genética , Proliferação de Células/genética , Feminino , Seguimentos , Gastrectomia , Humanos , Estimativa de Kaplan-Meier , Metástase Linfática/genética , Metástase Linfática/patologia , Masculino , MicroRNAs/isolamento & purificação , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Prognóstico , Reação em Cadeia da Polimerase em Tempo Real , Estômago/patologia , Estômago/cirurgia , Neoplasias Gástricas/mortalidade , Neoplasias Gástricas/patologia , Neoplasias Gástricas/cirurgia
14.
Chem Sci ; 10(27): 6683-6688, 2019 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-31367322

RESUMO

Growth of metal oxide layers on quantum dots (QDs) has been regarded as a good way to improve the photostability of QDs. However, direct growth of metal oxides on individual QD remains a great challenge. Here we report a novel approach to rapidly anchor metal oxides on QD surfaces through a sacrificial oxidation of a self-metal source strategy. As typical core/shell QDs, CdSe/CdS or aluminum doped CdSe/CdS (CdSe/CdS:Al) QDs were chosen and treated with peroxide (benzoyl peroxide). Self-metal sources (cadmium or/and aluminum) can be easily sacrificially oxidized, leading to the quick growth of cadmium oxide (CdO) or aluminum/cadmium hybrid oxides (Al2O3/CdO) on the surface of individual QD for improved photostability. Compared with CdO, Al2O3 possesses excellent barrier properties against moisture and oxygen. Therefore, CdSe/CdS QDs with the protection of an Al2O3/CdO hybrid layer show much superior photostability. Under strong illumination with blue light, the QDs coated with the Al2O3/CdO hybrid layer retained 100% of the original photoluminescence intensity after 70 h, while that of the untreated CdSe/CdS:Al, the treated CdSe/CdS and the CdSe/CdS QDs dropped to 65%, 45%, and 5%, respectively. Furthermore, we demonstrate that this method can be extended to other metal-doped QD systems, even including some inactive metals difficult to be oxidized spontaneously in an ambient atmosphere, which provides a new way to stabilize QDs for diverse optoelectronic applications.

15.
Molecules ; 24(6)2019 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-30917573

RESUMO

The longan industry produces a large amount of byproducts such as pericarp and seed, resulting in environmental pollution and resource wastage. The present study was performed to systematically evaluate functional components, i.e., polyphenols (phenolics and flavonoids) and alkaloids, in longan byproducts and their bioactivities, including antioxidant activities, nitrite scavenging activities in simulated gastric fluid and anti-hyperglycemic activities in vitro. Total phenolic and total flavonoid contents in pericarp were slightly higher than those in seeds, but seeds possessed higher alkaloid content than pericarp. Four polyphenolic substances, i.e., gallic acid, ethyl gallate, corilagin and ellagic acid, were identified and quantified using high-performance liquid chromatography. Among these polyphenolic components, corilagin was the major one in both pericarp and seed. Alkaloid extract in seed showed the highest DPPH radical scavenging activity and oxygen radical absorbance capacity. Nitrite scavenging activities were improved with extract concentration and reaction time increasing. Flavonoids in seed and alkaloids in pericarp had potential to be developed as anti-hyperglycemic agents. The research result was a good reference for exploring longan byproducts into various valuable health-care products.


Assuntos
Alcaloides/análise , Polifenóis/análise , Sapindaceae/química , Alcaloides/farmacologia , Antioxidantes/análise , Antioxidantes/farmacologia , Cromatografia Líquida de Alta Pressão , Hipoglicemiantes/análise , Hipoglicemiantes/farmacologia , Estrutura Molecular , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Polifenóis/farmacologia , Sementes/química
16.
Nanoscale ; 11(6): 2602-2607, 2019 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-30698576

RESUMO

The highly dynamic binding ligands on the surface of all-inorganic cesium lead halide perovskite quantum dots (PQDs), which can be easily lost or detached leading to a deterioration in the optical properties and stability, are one of the greatest challenges for the practical storage and application of PQDs. Herein, we report a facile metal ion-assisted ligand surface engineering strategy to synchronously boost the photoluminescence quantum yield and stability of CsPbBr3 PQDs by a sequential short-chain ligand (didodecyl dimethylammonium sulfide, DDA+-S2-) exchange and subsequent metal salt (In(Ac)3) treatment. From detailed characterization of the critical role of the metal ions, these enhancements were found to originate from the promoted ligand capping induced by the metal ions attached on the surface of the PQDs. Considering the shortened ligands and robust surface passivation, the modified CsPbBr3 PQDs exhibit drastically enhanced performance in an electroluminescent device. Our results have provided an insightful understanding of surface ligand engineering for high-quality and stable perovskite QDs and their effective optoelectronic applications.

17.
PeerJ ; 6: e5922, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30425899

RESUMO

The decomposition processes of accumulated cyanobacteria can release large amounts of organic carbon and affect the carbon cycling in shallow eutrophic lakes. However, the migration and transformation mechanisms of dissolved carbon (DC) require further study and discussion. In this study, a 73-day laboratory microcosm experiment using suction samplers (Rhizon and syringe) was conducted to understand the migration and transformation of DC during the cyanobacteria decomposition. The decomposition of cyanobacteria biomass caused anoxic and reduction conditions, and changed the acid-base environment in the water column. During the early incubation (days 0-18), a large amount of cyanobacteria-derived particulate organic matter (POM) was decomposed into dissolved organic carbon (DOC) in the overlying water, reaching the highest peak value of 1.82 g L-1 in the treatment added the high cyanobacteria biomass (470 g). After 18 days of incubation, the mineralization of increased DOC to dissolved inorganic carbon (DIC) maintained a high DIC level of overlying water in treatments added cyanobacteria biomass. The treatment added the medium cyanobacteria biomass (235 g) presented the lower DOC/total dissolved carbon ratio than the high cyanobacteria biomass associated with the lower mineralization from DOC to DIC. Due to the concentration differences of DIC at water-sediment interface, the main migration of DIC from pore water to overlying water occurred in the treatment without added cyanobacteria biomass. However, the treatments added the cyanobacteria biomass presented the obvious diffusion of DOC and the low migration of DIC at the water-sediment interface. The diffusive fluxes of DOC at the water-sediment interface increased with the cyanobacteria biomass added, reaching the maximum value of 411.01 mg/(m2·d) in the treatment added the high cyanobacteria biomass. In the overlying water, the group added the sediment and medium cyanobacteria biomass presented a faster degradation of cyanobacteria-derived POM to DOC and a higher mineralization level of DOC to DIC than added the medium cyanobacteria biomass without sediment. Therefore, during accumulated cyanobacteria decomposition, the biomass of accumulated cyanobacteria and sediment property can influence the migration and transformation of DC, playing an important role in carbon cycling in shallow eutrophic lakes.

18.
Chem Commun (Camb) ; 54(67): 9345-9348, 2018 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-30074028

RESUMO

A sequential surface adsorption method for improving the photostability of perovskite nanocrystals (NCs) at room temperature was proposed. Firstly, S2- was decorated on the surface of CsPbBr3 NCs by adding didodecyl dimethylammonium sulfide (S2--DDA+), and then In3+ ions, which diffused from the salt powder of In(Ac)3, were slowly adsorbed by the pre-loaded S2-. Through this process, the photoluminescence quantum yield of the CsPbBr3 NCs increases from 57% to 80%, and their photostability, thermal stability, and colloidal stability were all drastically improved. The resultant CsPbBr3·S-In NCs remained stable for 188 h under strong LED light illumination (450 nm and 175 mW cm-2), while pristine CsPbBr3 NCs totally quenched in 2 h, which shows the great potential of CsPbBr3·S-In NCs in lighting and display applications. We also demonstrated that this method could be extended to many other metal salts to form stable perovskite·S-X (X = Ni, Mn and Zn) nanocrystals.

19.
Huan Jing Ke Xue ; 39(3): 1180-1187, 2018 Mar 08.
Artigo em Chinês | MEDLINE | ID: mdl-29965462

RESUMO

Submerged macrophytes are an important component of aquatic ecosystems. During the growing period, submerged macrophytes can absorb nitrogen and phosphorus nutrients to reduce pollution loadings. Shoots of submerged macrophytes can also promote the adhesion of suspended substances in water, reducing the turbidity. The release of nutrients in sediments can be suppressed by its root system, and the resuspension of sediments caused by disturbance of winds and waves can also be resisted. The role of submerged macrophytes in ecological restoration of eutrophic lakes has attracted widespread attention. In 1960, the submerged plants Vallisneria natans and Potamogeton malaianus had been the dominant species in East Taihu. However after 2002, Nymphoides peltatum, Elodea nattalii, P. malaianus, etc. have gradually taken over the dominant roles along with significant elevations of nitrogen and phosphorus levels. Nutrients in water are not the only key factors causing eutrophication of water bodies; the nutrient source for submerged plant growth affect both the purification efficiency and the photosynthetic characteristics of submerged macrophytes. Excessive nitrogen and phosphorus concentrations can inhibit the photosynthetic physiological activities of submerged macrophytes, affecting the succession of aquatic vegetation. In addition, under high nutrient conditions, the competition from periphytic algae and planktonic algae may also directly poison submerged macrophytes, leading to its degradation and disappearance. Systematic studies on the regulation and photosynthetic fluorescence response mechanism of submerged macrophytes to varied nutrient loadings are helpful in revealing their relationships. The seedlings of submerged macrophyte V. natans were transplanted in a laboratory mesocosm to study the effect of nutrient loadings on its regulation of water nitrogen and phosphorus. Three nitrogen and phosphorus loadings from low, medium, and high levels derived from nitrate, ammonium, and phosphate were setup as the aquatic medium for the plant growth. Twelve harvests were carried out to determine the evolution of nutrient removal performance of V. natans. Its photosynthetic fluorescence characteristics were measured by a pulse-amplitude modulated fluorometer (Diving-PAM). Results showed that the nitrogen and phosphorus adsorption abilities of V. natans were gradually enhanced with the increase of nutrient concentrations in the range of TN ≤ 12 mg·L-1 and TP ≤ 1.0 mg·L-1. In the treatment of high nutrient concentrations (TN=12 mg·L-1 and TP=1.0 mg·L-1), the removal rates of nitrogen and phosphorus reached more than 95%. V. natans preferentially absorbed ammonium nitrogen when its concentration was high. The medium nutrient concentrations (TN:8-12 mg·L-1 and TP:0.6-1.0 mg·L-1) did not significantly affect the Fv/Fm ratio of leaves. However, the low nutrient concentrations (TN=3 mg·L-1 and TP=0.3 mg·L-1) could improve the Fv/Fm ratio of leaves and were beneficial for the growth of V. natans. The inhibition of photosynthetic activity and light tolerance were enhanced with the increase in nutrient concentrations. The photosynthetic activity of V. natans gradually recovered with no significant changes in the capacity for light harvesting, when the nutrient concentrations gradually decreased in the water. Our results indicate that the high nitrogen and phosphorus loadings indeed hamper the photosynthetic capacity, which may subsequently restrain the maintenance of the dominance of V. natans in the submerged macrophyte communities.


Assuntos
Hydrocharitaceae/metabolismo , Nitrogênio/análise , Fósforo/análise , Poluentes da Água/análise , Água/química , Fluorescência , Fotossíntese
20.
J Environ Manage ; 224: 147-155, 2018 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-30036809

RESUMO

The multiple proxies involving elemental and stable isotope ratios (C/N, δ15N and δ13C) and biomarkers are powerful tools for estimating sedimentary organic matter (SOM) sources. However, the systematic and reasonable evaluation of organic matter sources existing with serious spatial heterogeneity in large, shallow and eutrophic lakes is still far from clear. Samples of sediments, aquatic plants and particulate organic matter (POM) collected from different ecotype regions of Taihu Lake, China, including algae-type lakeshore, grass-type lakeshore, algae-grass-type lakeshore, inflow rivers and estuary, groove reed zone, offshore and central regions, were analyzed for their SOM sources via elemental and stable isotope ratios (C/N, δ15N and δ13C), n-alkanes and fatty acids (FA). More depleted δ13CTOC values (-26.3‰ to -25.4‰) and higher relative percentages of odd n-alkanes (C26 to C35) and long-chain FA (C24:0 to C32:0) clarified the influence of inflow rivers carrying terrestrial inputs on SOM. The higher relative percentages of n-alkanes from C14 to C20, FA (C16:0), and polyunsaturated FA (C18:2 and C18:3) in the reed belt of the groove demonstrated that some special terrain was important for the accumulation of algae-derived OM in sediments. Short-chain and middle-chain biomarker compounds revealed a large contribution from macrophytes in the grass-type region and an obvious algae-derived organic matter accumulation in the algae-type region, respectively. However, some overlapping ranges of C/N, δ15N and δ13C among aquatic plants, the ubiquity of lipid biomarkers compounds, anthropogenic influences, meteorological factors and lake topography caused some biased identification results for partial samples using different indicators. These biased identifications were mainly embodied in the source category and contribution difference based on principal component analysis and an end-member mixing model. Therefore, the estimation of SOM sources by multiple proxies cannot be uniformly applied in large freshwater lakes. The systematic investigation and comprehensive understanding of the different ecotypes and their surrounding environments are the important links in the identification of SOM sources via multiple indicators.


Assuntos
Eutrofização , Sedimentos Geológicos/química , Isótopos de Carbono , China , Monitoramento Ambiental , Lagos
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