148 research outputs found

    Photocatalytic TiO2/rGO/CuO Composite for Wastewater Treatment of Cr(VI) Under Visible Light

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    The harm of chromium pollution to the environment has caused a widespread concern; hexavalent chromium is a toxic, cancerogenic, and genetically mutagenic contaminant to the human body; by contrast, trivalent chromium is almost non-toxic to the human body; therefore, it is a feasible method to reduce hexavalent chromium to trivalent chromium. Photocatalysis is a new environmentally friendly and harmless technology, which can transform pollutants into non-toxic or less toxic products. In this study, we synthesized TiO2/rGO/CuO ternary nanocomposites to treat hexavalent chromium pollution under visible light. Under optimal conditions, the photoreduction efficiency of 100 ppm hexavalent chromium solution could reach 100% in 80 min. The photoreduction rate of hexavalent chromium is 29.4 times than that of pure TiO2. The photocatalytic property of CuO in TG2C8 nanocomposites is attributed to accelerate the separation of electrons and holes and the efficient electron transfer through the rGO framework. We believe that TiO2/rGO/CuO composites have great potential in wastewater treatment.publishedVersio

    Inhibition of Phosphodiesterase-4 Reverses Aβ-Induced Memory Impairment by Regulation of HPA Axis Related cAMP Signaling

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    Beta amyloid peptides (Aβ) are found to be associated with dysfunction of hypothalamic-pituitary-adrenal axis (HPA axis) that leads to memory and cognitive deficits in patients with Alzheimer’s disease (AD). Phosphodiesterase 4 (PDE4) inhibitors increase the intracellular cAMP activities, which may ameliorate cognitive deficits associated with AD. However, it remains unclear whether PDE4-mediated reversal of cognitive impairment in mouse model of AD is related to HPA axis and downstream cAMP-dependent pathway. The present study investigated the effects of PDE4 inhibitor rolipram on Aβ1-42-induced cognitive dysfunction and its underlying mechanisms. The step-down passive avoidance (PA) and Morris water-maze (MWM) tests were conducted 1 week (1 W), 2 months (2 M), and 6 months (6 M) after intracerebroventricular microjection (i.c.v.) of Aβ1-42. The results suggested that memory impairment emerged as early as 1 W, peaked at 2 M, and lasted until 6 M after injection. Chronic treatment with rolipram (0.1, 0.5, 1.0 mg/kg/d, i.p.) for 2 weeks (i.e., treatment started at 1.5 months after Aβ1-42 microinjection) dose-dependently improved memory performance in both MWM and PA tests. Moreover, rolipram reversed the Aβ-induced increases in serum corticosterone (CORT), corticotropin-releasing factor, and glucocorticoid receptors (CRF-R and GR) levels, whereas it decreases in brain-derived neurotropic factor (BDNF) and the ratio of pCREB to CREB expression. These effects of rolipram were prevented by pre-treatment with PKA inhibitor H89. The findings indicated that the protective effects of rolipram against Aβ1-42-induced memory deficits might involve HPA axis and cAMP-CREB-BDNF signaling

    The relationship between labial soft tissue changes and jumping spaces after immediate implant placement and restoration in the anterior maxilla: A prospective study

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    Oral implants have been increasingly used in the treatment of edentulous patients or those with dentition defects due to reliable treatment procedure and favorable long-term prognosis. We investigated the changes of labial soft tissue contours with different jumping spaces after immediate implant placement and restoration (IIPR) in the maxillary esthetic area and also provided a long-term stability measurement for the changing trend of soft tissue contour. All patients had been separated into three groups based on the jumping space: group A (horizontal defect dimension [HDD] 2 mm), group B (2 mm 3 mm) and the digital impressions were obtained in the first, third, and sixth month after the operation. The changes of gingival mucosa levels, the average thickness of soft tissue contour volume, and the linear change of submarginal level decreased gradually across the three groups, with the largest change of submarginal level being at 5mm. The size of the jumping space was moderately negatively correlated with the level and average thickness of gingival mucosa and the linear changes of 3 mm and 5 mm under gingival margin, while there was no significant correlation with pink esthetic score (PES) and the linear change of the 1 mm under the gingival margin. Generally, IIPR of upper anterior teeth can achieve esthetic satisfaction, and the level of soft tissue around the implant can be well preserved

    Regional and global elevational patterns of microbial species richness and evenness

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    8 páginas, 4 figurasAlthough elevational gradients in microbial biodiversity have attracted increasing attention recently, the generality in the patterns and underlying mechanisms are still poorly resolved. Further, previous studies focused mostly on species richness, while left understudied evenness, another important aspect of biodiversity. Here, we studied the elevational patterns in species richness and evenness of stream biofi lm bacteria and diatoms in six mountains in Asia and Europe. We also reviewed published results for elevational richness patterns for soil and stream microbes in a literature analysis. Our results revealed that even within the same ecosystem type (that is, stream) or geographical region, bacteria and diatoms showed contrasting patterns in diversity. Stream microbes, including present stream data, tend to show signifi cantly increasing or decreasing elevational patterns in richness, contrasting the fi ndings for soil microbes that typically showed nonsignifi cant or signifi cantly decreasing patterns. In all six mountains for bacteria and in four mountains for diatoms, species richness and evenness were positively correlated. Th e variation in bacteria and diatom richness and evenness were substantially explained by anthropogenic driven factors, such as total phosphorus (TP). However, diatom richness and evenness were also related to diff erent main drivers as richness was mostly related to pH, while evenness was most explained by TP. Our results highlight the lack of consistent elevational biodiversity patterns of microbes and further indicate that the two facets of biodiversity may respond diff erently to environmental gradients.JW was supported by NSFC grant 41273088, 41571058, 40903031 and CAS oversea visiting scholarship (2011-115). JS and JW were supported by Emil Aaltonen Foundation. JS and JW were supported by 973 Program (2012CB956100). Th e fi eld trips were partly supported by Air and Water Conservation Fund (GEFC12-14, National Geography of Science) to JW, and DISPERSAL 829/2013 from the Spanish National Parks Research Programme OAPNMAGRAMA to EOC.Peer reviewe

    MyoPS A Benchmark of Myocardial Pathology Segmentation Combining Three-Sequence Cardiac Magnetic Resonance Images

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    Assessment of myocardial viability is essential in diagnosis and treatment management of patients suffering from myocardial infarction, and classification of pathology on myocardium is the key to this assessment. This work defines a new task of medical image analysis, i.e., to perform myocardial pathology segmentation (MyoPS) combining three-sequence cardiac magnetic resonance (CMR) images, which was first proposed in the MyoPS challenge, in conjunction with MICCAI 2020. The challenge provided 45 paired and pre-aligned CMR images, allowing algorithms to combine the complementary information from the three CMR sequences for pathology segmentation. In this article, we provide details of the challenge, survey the works from fifteen participants and interpret their methods according to five aspects, i.e., preprocessing, data augmentation, learning strategy, model architecture and post-processing. In addition, we analyze the results with respect to different factors, in order to examine the key obstacles and explore potential of solutions, as well as to provide a benchmark for future research. We conclude that while promising results have been reported, the research is still in the early stage, and more in-depth exploration is needed before a successful application to the clinics. Note that MyoPS data and evaluation tool continue to be publicly available upon registration via its homepage (www.sdspeople.fudan.edu.cn/zhuangxiahai/0/myops20/)

    Dietary Modulation of Gut Microbiota Contributes to Alleviation of Both Genetic and Simple Obesity in Children

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    Gut microbiota has been implicated as a pivotal contributing factor in diet-related obesity; however, its role in development of disease phenotypes in human genetic obesity such as Prader–Willi syndrome (PWS) remains elusive. In this hospitalized intervention trial with PWS (n = 17) and simple obesity (n = 21) children, a diet rich in non-digestible carbohydrates induced significant weight loss and concomitant structural changes of the gut microbiota together with reduction of serum antigen load and alleviation of inflammation. Co-abundance network analysis of 161 prevalent bacterial draft genomes assembled directly from metagenomic datasets showed relative increase of functional genome groups for acetate production from carbohydrates fermentation. NMR-based metabolomic profiling of urine showed diet-induced overall changes of host metabotypes and identified significantly reduced trimethylamine N-oxide and indoxyl sulfate, host-bacteria co-metabolites known to induce metabolic deteriorations. Specific bacterial genomes that were correlated with urine levels of these detrimental co-metabolites were found to encode enzyme genes for production of their precursors by fermentation of choline or tryptophan in the gut. When transplanted into germ-free mice, the pre-intervention gut microbiota induced higher inflammation and larger adipocytes compared with the post-intervention microbiota from the same volunteer. Our multi-omics-based systems analysis indicates a significant etiological contribution of dysbiotic gut microbiota to both genetic and simple obesity in children, implicating a potentially effective target for alleviation

    TNFα Cooperates with IFN-γ to Repress Bcl-xL Expression to Sensitize Metastatic Colon Carcinoma Cells to TRAIL-mediated Apoptosis

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    BACKGROUND: TNF-related apoptosis-inducing ligand (TRAIL) is an immune effector molecule that functions as a selective anti-tumor agent. However, tumor cells, especially metastatic tumor cells often exhibit a TRAIL-resistant phenotype, which is currently a major impediment in TRAIL therapy. The aim of this study is to investigate the synergistic effect of TNFα and IFN-γ in sensitizing metastatic colon carcinoma cells to TRAIL-mediated apoptosis. METHODOLOGY/PRINCIPAL FINDINGS: The efficacy and underlying molecular mechanism of cooperation between TNFα and IFN-γ in sensitizing metastatic colon carcinoma cells to TRAIL-mediated apoptosis were examined. The functional significance of TNFα- and IFN-γ-producing T lymphocyte immunotherapy in combination with TRAIL therapy in suppression of colon carcinoma metastasis was determined in an experimental metastasis mouse model. We observed that TNFα or IFN-γ alone exhibits minimal sensitization effects, but effectively sensitized metastatic colon carcinoma cells to TRAIL-induced apoptosis when used in combination. TNFα and IFN-γ cooperate to repress Bcl-xL expression, whereas TNFα represses Survivin expression in the metastatic colon carcinoma cells. Silencing Bcl-xL expression significantly increased the metastatic colon carcinoma cell sensitivity to TRAIL-induced apoptosis. Conversely, overexpression of Bcl-xL significantly decreased the tumor cell sensitivity to TRAIL-induced apoptosis. Furthermore, TNFα and IFN-γ also synergistically enhanced TRAIL-induced caspase-8 activation. TNFα and IFN-γ was up-regulated in activated primary and tumor-specific T cells. TRAIL was expressed in tumor-infiltrating immune cells in vivo, and in tumor-specific cytotoxic T lymphocytes (CTL) ex vivo. Consequently, TRAIL therapy in combination with TNFα/IFN-γ-producing CTL adoptive transfer immunotherapy effectively suppressed colon carcinoma metastasis in vivo. CONCLUSIONS/SIGNIFICANCE: TNFα and IFN-γ cooperate to overcome TRAIL resistance at least partially through enhancing caspase 8 activation and repressing Bcl-xL expression. Combined CTL immunotherapy and TRAIL therapy hold great promise for further development for the treatment of metastatic colorectal cancer

    Synthesis and Immobilization of Defect-enriched Photocatalyst for Plastic Upcycling

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    With the widespread global use and production of plastic, the accumulation of plastic waste places a huge amount of energy stress on the planet and causes significant negative environmental impacts. A large amount of this waste is sent to landfill or discarded into oceans, but the leakage of toxic compounds from landfills results in soil and groundwater contamination, whilst plastic discarded into oceans causes significant issues for marine life. Even worse, these plastics naturally decompose into micro- or nano-sized particles, thereby endangering not only the health of marine life, but also the entire ecosystem and food chain.The chemical upcycling of waste plastic – as a supplementary recycling method to traditional treatment options – has garnered attention in recent years. Chemical upcycling aims to upgrade low-cost waste plastics into high-value products, including fuels, valuable chemicals and carbon materials, and to encourage a circular plastics economy. Recently, photocatalysis – as a green, energy-saving and sustainable technology – has been studied for plastic upcycling. Products resulting from photocatalytic upcycling include fuels such as hydrogen, chemicals such as acetic acid and materials such as fluoroalkylated polystyrene. However, the photocatalytic upcycling of plastics as an emerging area still suffers from low plastic conversion efficiency and product selectivity. To overcome this obstacle, and to achieve the goal of ensuring practical applications for photocatalytic upcycling, it is crucial to develop an efficient photocatalyst with high photon utilization efficiency and high charge migration efficiency. Moreover, immobilizing the photocatalyst on supporting material for an up-scale application is also important, as it can address the difficulties involved in separating and recovering powder photocatalysts and increasing the light contact area.Based on the abovementioned discussion, this thesis focuses on developing efficient photocatalysts and immobilizing the photocatalyst for plastic upcycling. Defect engineering is the main method employed to modify photocatalysts in this thesis, and it includes introducing oxygen vacancies and platinum through solution plasma, creating lattice distortion by constructing a high entropy photocatalyst, and creating both cation and oxygen vacancies through alkali-etching the high-entropy photocatalyst template. The structure, morphology, and optical and electrochemical properties of photocatalysts are analyzed by a series of characterizations. The immobilization methods of photocatalysts include fabricating mixed matrix membranes through electrospinning technology and in-situ growth of photocatalyst through hydrothermal method using electrospinning fiber membrane as a template, in-situ growth of photocatalyst through hydrothermal method using nickel foam as a template. The immobilized photocatalysts are fixed in a photocatalytic membrane reactor for PLA, PVC, and UHMWPE upcycling. Photocatalytic performance is evaluated by analyzing the yield efficiency and the selectivity of products. Moreover, photocatalyst modification mechanisms, as well as the pathways involved in plastic upcycling, are disclosed and discussed herein.Firstly, the solution plasma method is applied to modify the bismuth oxycholoride photocatalyst Bi12O17Cl2, to introduce oxygen vacancies and platinum particles. It is confirmed that, through introducing oxygen vacancies, the light adsorption spectrum is significantly extended. Platinum and oxygen vacancies facilitate the charge separation efficiency, in which case the modified Bi12O17Cl2 exhibits largely improved PVC and PLA photocatalytic upcycling efficiency compared to the initial Bi12O17Cl2. Electrospinning is utilized to immobilize the photocatalyst through fabricating a mixed matrix membrane, which is used in a photocatalytic membrane reactor to evaluate the performance. However, due to the low amount of immobilized photocatalyst on a certain area of the membrane, and the active sites blocked by polymer during the electrospinning process, the product yield rates in the photocatalytic membrane reactor are significantly lower than that in batch experiments.Subsequently, in order to increase the density of the photocatalyst on the supporting material and increase the exposure of active sites, a hydrothermal-assisted in-situ growth strategy is developed to immobilize the photocatalyst on the surface of the polymer membrane. Moreover, by constructing a high-entropy metal tungstates XWO4 photocatalyst, the lattice defect is introduced, which can create additional active sites and thus facilitate the production of active species. Thus, the XWO4 photocatalytic membrane exhibits improved PLA upcycling efficiency compared to the single metal-based control samples.Lastly, the high-entropy photocatalyst, CoNiZnFeAl-LDH, is prepared as a template to construct a cation vacancy-enriched photocatalyst (CoNivacFevac-LDH) and immobilized on nickel foam. The PMS is introduced into the photocatalytic system to construct a photo-Fenton-like catalysis reaction to improve the oxidation ability of the overall system. The SO4•- produced through PMS activation has a longer lifetime (30-40 μs) compared to •OH (10-3 μs), which is beneficial for heterogeneous catalysis with solid plastics. The electrochemical experimental results indicate that cation vacancy improves the electron transfer between PMS and CoNivacFevac-LDH compared to that between PMS and CoNiFe-LDH. Therefore, CoNivacFevac-LDH exhibits high UHMWPE conversion efficiency and an equally high acetic acid yield rate.Overall, this thesis offers insights into the synthesizing of defect-enriched photocatalysts and the immobilization strategies for plastic upcycling

    Photocatalytic TiO2/rGO/CuO Composite for Wastewater Treatment of Cr(VI) Under Visible Light

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    The harm of chromium pollution to the environment has caused a widespread concern; hexavalent chromium is a toxic, cancerogenic, and genetically mutagenic contaminant to the human body; by contrast, trivalent chromium is almost non-toxic to the human body; therefore, it is a feasible method to reduce hexavalent chromium to trivalent chromium. Photocatalysis is a new environmentally friendly and harmless technology, which can transform pollutants into non-toxic or less toxic products. In this study, we synthesized TiO2/rGO/CuO ternary nanocomposites to treat hexavalent chromium pollution under visible light. Under optimal conditions, the photoreduction efficiency of 100 ppm hexavalent chromium solution could reach 100% in 80 min. The photoreduction rate of hexavalent chromium is 29.4 times than that of pure TiO2. The photocatalytic property of CuO in TG2C8 nanocomposites is attributed to accelerate the separation of electrons and holes and the efficient electron transfer through the rGO framework. We believe that TiO2/rGO/CuO composites have great potential in wastewater treatment
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