| 1. |
- Sampson, Joshua N., et al.
(författare)
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Analysis of Heritability and Shared Heritability Based on Genome-Wide Association Studies for 13 Cancer Types
- 2015
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Ingår i: Journal of the National Cancer Institute. - : Oxford University Press (OUP). - 0027-8874 .- 1460-2105. ; 107:12
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Tidskriftsartikel (refereegranskat)abstract
- Background: Studies of related individuals have consistently demonstrated notable familial aggregation of cancer. We aim to estimate the heritability and genetic correlation attributable to the additive effects of common single-nucleotide polymorphisms (SNPs) for cancer at 13 anatomical sites. Methods: Between 2007 and 2014, the US National Cancer Institute has generated data from genome-wide association studies (GWAS) for 49 492 cancer case patients and 34 131 control patients. We apply novel mixed model methodology (GCTA) to this GWAS data to estimate the heritability of individual cancers, as well as the proportion of heritability attributable to cigarette smoking in smoking-related cancers, and the genetic correlation between pairs of cancers. Results: GWAS heritability was statistically significant at nearly all sites, with the estimates of array-based heritability, h(l)(2), on the liability threshold (LT) scale ranging from 0.05 to 0.38. Estimating the combined heritability of multiple smoking characteristics, we calculate that at least 24% (95% confidence interval [CI] = 14% to 37%) and 7% (95% CI = 4% to 11%) of the heritability for lung and bladder cancer, respectively, can be attributed to genetic determinants of smoking. Most pairs of cancers studied did not show evidence of strong genetic correlation. We found only four pairs of cancers with marginally statistically significant correlations, specifically kidney and testes (rho = 0.73, SE = 0.28), diffuse large B-cell lymphoma (DLBCL) and pediatric osteosarcoma (rho = 0.53, SE = 0.21), DLBCL and chronic lymphocytic leukemia (CLL) (rho = 0.51, SE = 0.18), and bladder and lung (rho = 0.35, SE = 0.14). Correlation analysis also indicates that the genetic architecture of lung cancer differs between a smoking population of European ancestry and a nonsmoking Asian population, allowing for the possibility that the genetic etiology for the same disease can vary by population and environmental exposures. Conclusion: Our results provide important insights into the genetic architecture of cancers and suggest new avenues for investigation.
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| 2. |
- Smedby, Karin E., et al.
(författare)
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GWAS of Follicular Lymphoma Reveals Allelic Heterogeneity at 6p21.32 and Suggests Shared Genetic Susceptibility with Diffuse Large B-cell Lymphoma
- 2011
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Ingår i: PLoS Genetics. - : Public Library of Science (PLoS). - 1553-7390 .- 1553-7404. ; 7:4, s. e1001378-
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Tidskriftsartikel (refereegranskat)abstract
- Non-Hodgkin lymphoma (NHL) represents a diverse group of hematological malignancies, of which follicular lymphoma (FL) is a prevalent subtype. A previous genome-wide association study has established a marker, rs10484561 in the human leukocyte antigen (HLA) class II region on 6p21.32 associated with increased FL risk. Here, in a three-stage genome-wide association study, starting with a genome-wide scan of 379 FL cases and 791 controls followed by validation in 1,049 cases and 5,790 controls, we identified a second independent FL-associated locus on 6p21.32, rs2647012 (ORcombined = 0.64, P-combined= 2x10(-21)) located 962 bp away from rs10484561 (r(2)< 0.1 in controls). After mutual adjustment, the associations at the two SNPs remained genome-wide significant (rs2647012: ORadjusted = 0.70, P-adjusted= 4x10(-12); rs10484561: ORadjusted = 1.64, P-adjusted= 5x10(-15)). Haplotype and coalescence analyses indicated that rs2647012 arose on an evolutionarily distinct haplotype from that of rs10484561 and tags a novel allele with an opposite (protective) effect on FL risk. Moreover, in a follow-up analysis of the top 6 FL-associated SNPs in 4,449 cases of other NHL subtypes, rs10484561 was associated with risk of diffuse large B-cell lymphoma (ORcombined = 1.36, P-combined = 1.4x10(-7)). Our results reveal the presence of allelic heterogeneity within the HLA class II region influencing FL susceptibility and indicate a possible shared genetic etiology with diffuse large B-cell lymphoma. These findings suggest that the HLA class II region plays a complex yet important role in NHL.
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| 3. |
- Sun, Jianteng, et al.
(författare)
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Hydroxylated polybrominated diphenyl ethers (OH-PBDEs) in biosolids from municipal wastewater treatment plants in China
- 2013
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Ingår i: Chemosphere. - : Elsevier. - 0045-6535 .- 1879-1298. ; 90:9, s. 2388-2395
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Tidskriftsartikel (refereegranskat)abstract
- Hydroxylated polybrominated diphenyl ethers (OH-PBDEs) along with methoxylated polybrominated diphenyl ethers (MeO-PBDEs) have been frequently identified as natural compounds in marine environment and also assumed as metabolites of PBDEs. In the present study, nine OH-PBDE, nine MeO-PBDE and 10 PBDE congeners were studied in the sewage sludge collected from 36 municipal wastewater treatment plants (WWTPs) in 27 cities of China. The results suggest that OH-PBDEs and PBDEs are ubiquitous in sewage sludge in China, however, methoxylated PBDEs were not detectable. Composition profiles of detected OH-PBDE congeners were different depending on the sampling location. ΣOH-PBDEs in WWTPs sludge ranged from 0.04 to 2.24 ng g-1 dry weight (mean: 0.35 ng g-1 dry weight). The total amount of the two most prominent congeners (6-OH-BDE-47+2'-OH-BDE-68) accounted for about 53.3-100% of the sum of all six identified congeners. A significant linear relationship was found between 6-OH-BDE-47 and 2'-OH-BDE-68. A distinct geographical distribution of ΣOH-PBDEs was observed with greater concentrations of OH-PBDEs at coastal areas than inland regions in China.
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| 4. |
- Wang, Longwei, et al.
(författare)
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A Molybdenum Disulfide Nanozyme with Charge-Enhanced Activity for Ultrasound-Mediated Cascade-Catalytic Tumor Ferroptosis
- 2023
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Ingår i: Angewandte Chemie - International Edition. - : Wiley. - 1433-7851 .- 1521-3773. ; 62:11
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Tidskriftsartikel (refereegranskat)abstract
- The deficient catalytic activity of nanozymes and insufficient endogenous H2O2 in the tumor microenvironment (TME) are major obstacles for nanozyme-mediated catalytic tumor therapy. Since electron transfer is the basic essence of catalysis-mediated redox reactions, we explored the contributing factors of enzymatic activity based on positive and negative charges, which are experimentally and theoretically demonstrated to enhance the peroxidase (POD)-like activity of a MoS2 nanozyme. Hence, an acidic tumor microenvironment-responsive and ultrasound-mediated cascade nanocatalyst (BTO/MoS2@CA) is presented that is made from few-layer MoS2 nanosheets grown on the surface of piezoelectric tetragonal barium titanate (T-BTO) and modified with pH-responsive cinnamaldehyde (CA). The integration of pH-responsive CA-mediated H2O2 self-supply, ultrasound-mediated charge-enhanced enzymatic activity, and glutathione (GSH) depletion enables out-of-balance redox homeostasis, leading to effective tumor ferroptosis with minimal side effects.
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| 5. |
- Xu, HT, et al.
(författare)
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Abnormal beta-catenin and reduced axin expression are associated with poor differentiation and progression in non-small cell lung cancer
- 2006
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Ingår i: American Journal of Clinical Pathology. - 0002-9173 .- 1943-7722. ; 125:4, s. 534-541
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Tidskriftsartikel (refereegranskat)abstract
- We studied the expression of axin and beta-catenin and their relation to clinicopathologic factors in 100 non-small cell lung cancers (NSCLCs) by immunohistochemical analysis. The mutation in exon 3 of the beta-catenin gene was examined by polymerase chain reaction and direct sequencing. Preserved axin expression was significantly higher in well- and moderately differentiated NSCLC samples than in poorly differentiated ones. Reduced membranous expression of beta-catenin was shown in 80 cases, whereas 26 cases had aberrant nuclear expression. Poor differentiation and lymph node metastasis were associated significantly with reduced beta-catenin expression. Lower axin expression was related significantly to higher nuclear beta-catenin expression. However, this study failed to detect any exon 3 mutation in the beta-catenin gene in the 100 NSCLC samples. We conclude that reduced beta-catenin and axin expression might predict poor differentiation in NSCLC. Reduced axin expression, but not mutation in exon 3, might be an important explanation for the abnormal beta-catenin expression in NSCLC.
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| 6. |
- Yang, Wenxing, et al.
(författare)
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Surface-Ligand "Liquid" to "Crystalline" Phase Transition Modulates the Solar H2 Production Quantum Efficiency of CdS Nanorod/Mediator/Hydrogenase Assemblies
- 2020
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Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 12:31, s. 35614-35625
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Tidskriftsartikel (refereegranskat)abstract
- This study reports how the length of capping ligands on a nanocrystal surface affects its interfacial electron transfer (ET) with surrounding molecular electron acceptors, and consequently, impact the H-2 production of a biotic-abiotic hybrid artificial photosynthetic system. Specifically, we study how the H-2 production efficiency of a hybrid system, combining CdS nanorods (NRs), [NiFe] hydrogenase, and redox mediators (propyl-bridged 2,2'-bipyridinium, PDQ(2+)), depends on the alkyl chain length of mercaptocarboxylate ligands on the NR surface. We observe a minor decrease of the quantum yield for H-2 production from 54 +/- 6 to 43 +/- 2% when varying the number of methylene units in the ligands from 2 to 7. In contrast, an abrupt decrease of the yield was observed from 43 +/- 2 to 4 +/- 1% when further increasing n from 7 to 11. ET studies reveal that the intrinsic ET rates from the NRs to the electron acceptor PDQ(2+) are all within 10(8) -10(9) s(-1) regardless of the length of the capping ligands. However, the number of adsorbed PDQ(2+) molecules on NR surfaces decreases dramatically when n >= 10, with the saturating number changing from 45 +/- 5 to 0.3 +/- 0.1 for n = 2 and 11, respectively. These results are not consistent with the commonly perceived exponential dependence of ET rates on the ligand length. Instead, they can be explained by the change of the accessibility of NR surfaces to electron acceptors from a disordered "liquid" phase at n < 7 to a more ordered "crystalline" phases at n > similar to 7. These results highlight that the order of capping ligands is an important design parameter for further constructing nanocrystal/molecular assemblies in broad nanocrystal-based applications.
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| 7. |
- Zhang, Haiyan, et al.
(författare)
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Polychlorinated naphthalenes in sewage sludge from wastewater treatment plants in China
- 2014
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Ingår i: Science of the Total Environment. - : Elsevier. - 0048-9697 .- 1879-1026. ; 490, s. 555-560
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Tidskriftsartikel (refereegranskat)abstract
- Polychlorinated naphthalenes (PCNs) were nominated as persistent organic pollutants candidate in the Stockholm Convention in 2011. In this study, the profiles, concentrations and spatial distributions of PCNs were analyzed in 30 sewage sludge samples from wastewater treatment plants (WWTPs) in China. Concentrations of Σ75PCNs in sludge samples were in the range of 1.05-10.9 ng/g dry weight (dw) with a mean value of 3.98 ng/g dw. The predominant homologues in the sludge were mono- to tetra-CNs, accounting for approximately 85% of total PCNs. The total toxic equivalent quantities (TEQs) of dioxin-like PCN congeners ranged from 0.04 to 2.28 pg/g dw with a mean value of 0.36 pg/g dw, which were lower than the maximum permissible TEQ concentrations in sludge for land application in China. Levels of PCNs and TEQs in sludge were relatively higher in samples from highly industrialized and developed cities in eastern China, implying a possible link between PCN contamination and the local economic development, but more studies are warranted to corroborate this. Industrial sources might be important contributors of PCNs to sewage sludge in China.
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| 8. |
- Bjurstöm, Helen, et al.
(författare)
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GABA, a natural immunomodulator of T lymphocytes.
- 2008
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Ingår i: Journal of Neuroimmunology. - : Elsevier BV. - 1872-8421 .- 0165-5728. ; 205:1-2, s. 44-50
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Tidskriftsartikel (refereegranskat)abstract
- gamma-aminobutyric acid (GABA) is the main neuroinhibitory transmitter in the brain. Here we show that GABA in the extracellular space may affect the fate of pathogenic T lymphocytes entering the brain. We examined in encephalitogenic T cells if they expressed functional GABA channels that could be activated by the low (nM-1 microM), physiological concentrations of GABA present around neurons in the brain. The cells expressed the alpha1, alpha4, beta2, beta3, gamma1 and delta GABAA channel subunits and formed functional, extrasynaptic-like GABA channels that were activated by 1 microM GABA. 100 nM and higher GABA concentrations decreased T cell proliferation. The results are consistent with GABA being immunomodulatory.
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| 9. |
- Cao, Huiming, et al.
(författare)
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Effect of Enterohepatic Circulation on the Accumulation of Per- and Polyfluoroalkyl Substances : Evidence from Experimental and Computational Studies
- 2022
-
Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 56:5, s. 3214-3224
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Tidskriftsartikel (refereegranskat)abstract
- The pharmacokinetic characteristics of per- and polyfluoroalkyl substances (PFAS) affect their distribution and bioaccumulation in biological systems. The enterohepatic circulation leads to reabsorption of certain chemicals from bile back into blood and the liver and thus influences their elimination, yet its influence on PFAS bioaccumulation remains unclear. We explored the role of enterohepatic circulation in PFAS bioaccumulation by examining tissue distribution of various PFAS in wild fish and a rat model. Computational models were used to determine the reabsorbed fractions of PFAS by calculating binding affinities of PFAS for key transporter proteins of enterohepatic circulation. The results indicated that higher concentrations were observed in blood, the liver, and bile compared to other tissues for some PFAS in fish. Furthermore, exposure to a PFAS mixture on the rat model showed that the reabsorption phenomenon appeared during 8-12 h for most long-chain PFAS. Molecular docking calculations suggest that PFAS can bind to key transporter proteins via electrostatic and hydrophobic interactions. Further regression analysis adds support to the hypothesis that binding affinity of the apical sodium-dependent bile acid transporter is the most important variable to predict the human half-lives of PFAS. This study demonstrated the critical role of enterohepatic circulation in reabsorption, distribution, and accumulation of PFAS.
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| 10. |
- Cao, Huiming, et al.
(författare)
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Screening of Potential PFOS Alternatives To Decrease Liver Bioaccumulation : Experimental and Computational Approaches
- 2019
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 53:5, s. 2811-2819
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Tidskriftsartikel (refereegranskat)abstract
- Perfluorooctanesulfonate (PFOS) is a persistent organic pollutant with significant bioaccumulation potential in liver tissues. Exposure to PFOS could cause increase of liver weight, induce adenomas of the liver, and cause hepatomegaly. Alternatives of PFOS might be designed and synthesized that have significantly lower liver bioaccumulation. In this study, we conducted animal exposure experiments to investigate tissue accumulations of 14 per- and polyfluoroalkyl substances. Correlation analysis demonstrated that accumulation of the compounds in rat liver had strong correlations with their binding affinities of liver fatty acid binding protein (LFABP). Thus, we combined a quantitative structure-activity relationship model with molecular dynamics (MD) simulations to develop computational models to predict the LFABP binding affinities of two newly synthesized alternatives, perfluorodecalin-2-sulfonic acid and N-diperfluorobutanoic acid. The binding characteristics of the PFOS alternatives for LFABP were elaborated to explore how the different structural modifications of molecules influenced the underlying binding mechanisms. Subsequent animal experiments demonstrated that the binding free energy calculations based on the MD simulations provided a good indicator to reflect the relative degree of liver accumulation of the PFOS alternatives in the same exposure doses and durations. Our findings from the combination of experimental exposure and computational model can provide helpful information to design potential alternatives of PFOS with weak LFABP binding capability and low liver accumulation.
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| 11. |
- Conde, Lucia, et al.
(författare)
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Genome-wide association study of follicular lymphoma identifies a risk locus at 6p21.32
- 2010
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 42:8, s. 661-664
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Tidskriftsartikel (refereegranskat)abstract
- To identify susceptibility loci for non-Hodgkin lymphoma subtypes, we conducted a three-stage genome-wide association study. We identified two variants associated with follicular lymphoma at 6p21.32 (rs10484561, combined P = 1.12 x 10(-29) and rs7755224, combined P = 2.00 x 10(-19); r(2) = 1.0), supporting the idea that major histocompatibility complex genetic variation influences follicular lymphoma susceptibility. We also found confirmatory evidence of a previously reported association between chronic lymphocytic leukemia/small lymphocytic lymphoma and rs735665 (combined P = 4.24 x 10(-9)).
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| 12. |
- Ejlerskov, Patrick, et al.
(författare)
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Lack of Neuronal IFN-β-IFNAR Causes Lewy Body- and Parkinson's Disease-like Dementia.
- 2015
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Ingår i: Cell. - : Elsevier BV. - 1097-4172 .- 0092-8674. ; 163:2, s. 324-339
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Tidskriftsartikel (refereegranskat)abstract
- Neurodegenerative diseases have been linked to inflammation, but whether altered immunomodulation plays a causative role in neurodegeneration is not clear. We show that lack of cytokine interferon-β (IFN-β) signaling causes spontaneous neurodegeneration in the absence of neurodegenerative disease-causing mutant proteins. Mice lacking Ifnb function exhibited motor and cognitive learning impairments with accompanying α-synuclein-containing Lewy bodies in the brain, as well as a reduction in dopaminergic neurons and defective dopamine signaling in the nigrostriatal region. Lack of IFN-β signaling caused defects in neuronal autophagy prior to α-synucleinopathy, which was associated with accumulation of senescent mitochondria. Recombinant IFN-β promoted neurite growth and branching, autophagy flux, and α-synuclein degradation in neurons. In addition, lentiviral IFN-β overexpression prevented dopaminergic neuron loss in a familial Parkinson's disease model. These results indicate a protective role for IFN-β in neuronal homeostasis and validate Ifnb mutant mice as a model for sporadic Lewy body and Parkinson's disease dementia.
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| 13. |
- Inacio, Ana, et al.
(författare)
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Endogenous IFN-β signaling exerts anti-inflammatory actions in experimentally induced focal cerebral ischemia.
- 2015
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Ingår i: Journal of Neuroinflammation. - : Springer Science and Business Media LLC. - 1742-2094. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- Interferon (IFN)-β exerts anti-inflammatory effects, coupled to remarkable neurological improvements in multiple sclerosis, a neuroinflammatory condition of the central nervous system. Analogously, it has been hypothesized that IFN-β, by limiting inflammation, decreases neuronal death and promotes functional recovery after stroke. However, the core actions of endogenous IFN-β signaling in stroke are unclear.
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| 14. |
- Liu, Yawei, 1967-
(författare)
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Effects of pH on platelets release of growth factors in wound healing
- 2003
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Wound healing is thought to involve a complex series of interactions between biochemical mediators, cells and extracellular matrix. Known to stimulate cellular movement, proliferation and biosynthetic activity, growth factors may play a significant role in stimulating wound repair. This thesis focuses on the early phase of wound healing. We established an experimental model which mimics the early proliferative stage and concentrated on a potentially interesting aspect of the wound environment pH as a modulator of the release of growth factors from platelets. The influence of platelet-rich plasma lysates on fibroblast proliferation at varying pH was studied in culture. We found that the concentration of platelet-derived growth factor in the different lysates was highest at pH 5.0. The concentration of transforming growth factor beta, however, was lower after incubation at pH 5.0 than at pH 7.1 and 7.6. Fibroblast proliferation and collagen production were enhanced by platelet lysates at pH 5.0, 7.1 and 7.6.We also studied the release of growth factors from platelet supernatants which were thrombin-activated at pH 7.4, then the pH was lowered to 5.0, remained the same or was raised to 8.5, or were thrombin-activated (or not) at pH 5.0, 7.4 and 8.5. Our results suggest that release of growth factors is dependent not only on platelet activation, but also on long-term incubation at 37°C and change in pH. ln summary, we found that pH may influence the activity of platelet proteins, resulting in fibroblast growth and promotion of wound healing.
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| 15. |
- Liu, Yawei, et al.
(författare)
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Endogenous collagen peptide activation of CD1d-restricted NKT cells ameliorates tissue-specific inflammation in mice
- 2011
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Ingår i: Journal of Clinical Investigation. - 0021-9738 .- 1558-8238. ; 121:1, s. 249-264
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Tidskriftsartikel (refereegranskat)abstract
- NKT cells m the mouse recognize antigen in the context of the MHC class I-like molecule CD1d and play an important role in peripheral tolerance and protection against autoimmune and other diseases NKT cells are usually activated by CD1d-presented lipid antigens However, peptide recognition m the context of CD 1 has also been documented, although no self-peptide ligands have been reported to date Here, we have identified an endogenous peptide that is presented by CD1d to activate mouse NKT cells This peptide, the immunodominant epitope from mouse collagen type II (mCII(707-721)), was not associated with either MHC class I or II Activation of CD1d-restricted mCII(707-721)-specific NKT cells was induced via TCR signaling and classical costimulation hi addition, mCII(707-721)-specific NKT cells induced T cell death through Fas/FasL, man IL-17A-independent fashion Moreover, mCII(707-721)-specific NKT cells suppressed a range of in vivo inflammatory conditions, including delayed-type hypersensitivity, antigen-induced airway inflammation, collagen-induced arthritis, and EAE, which were all ameliorated by mCII(707) (721) vaccination The findings presented here offer new insight into the intrinsic roles of NKT cells in health and disease Given the results, endogenous collagen peptide activators of NKT cells may offer promise as novel therapeutics in tissue-specific autoimmune and inflammatory diseases
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| 16. |
- Liu, Yawei, 1967-, et al.
(författare)
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Fibroblast proliferation due to exposure to a platelet concentrate in vitro is pH dependent
- 2002
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Ingår i: Wound Repair and Regeneration. - 1067-1927 .- 1524-475X. ; 10:5, s. 336-340
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Tidskriftsartikel (refereegranskat)abstract
- The influence of platelet-rich plasma lysates on fibroblast proliferation was studied in culture. Cells were exposed to platelet lysates that had been preincubated at different pHs (5.0, 7.1, and 7.6). Proliferation was evaluated with the MTT assay and incorporation of [3H]thymidine into macromolecules, while type I collagen production was assayed by Western blotting. Enzyme-linked immunosorbent assays were used to determine platelet-derived growth factor and transforming growth factor-β concentrations. Platelets preincubated in an acidic environment (pH 5.0) induced the highest degree of fibroblast proliferation, and the concentration of platelet-derived growth factor in the different treated lysates was the highest at that particular pH. The concentration of transforming growth factor-β, however, was lower after incubation at pH 5.0 than at either pH 7.1 or 7.6. These findings may be relevant to normal wound healing in vivo and useful in the treatment of wounds and delayed healing processes.
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| 17. |
- Liu, Yawei
(författare)
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Neruons; regulators of CNS inflammation
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Neurons have been neglected as cells with major immune regulatory function. Here, we present novel data demonstrating that neurons are highly immune competent and play crucial role in regulation of T cell response and CNS inflammation. Neurons induce proliferation of activated CD4+T cells via B7-CD28 and TGF-?1-TGF-?R signaling pathways with amplification of TCR signaling and increased phosphorylated ZAP-70, IL-2 and IL-9. Neuron-T cell interaction results in conversion of encephalitogenic T cells to CD25+TGF-?1+CTLA-4+ Tregulatory cells which suppress T cells proliferation and inhibit EAE. The suppression is dependent on CTLA-4 but not TGF-?1. However, autocrine action of TGF-?1 is important for proliferative arrest of Treg cells. Early enrichment of membrane-bound TGF-?1+CD4+ T cells in CNS of EAE mice proceeded by intracellular production of TGF-?1 and generation of CD25+TGF-?1+CTLA-4+ Treg cells, these cells in turn prevent EAE. This reveals the physiological importance of the generation of Treg cells in CNS upon interaction with neurons with a key role to down-regulate CNS inflammation. In addition, neurons upregulate PD-L1 upon interaction with encephalitogenic T cells, which in turns leads to generation of a CD4highPD-L1high T cell population. Mice deficient in IFN-? are defective in upregulation of this pathway. This defect is associated with absence of PD-L1 upregulation on motor neurons in the CNS, defective in situ generation of CD4highPD-L1high T cells as well as augmented EAE. Hence, motor neurons in addition to their capacity to generate Treg cells from committed encephalitogic T cells, are crucial in regulation of CNS inflammation through a secondary mechanism leading to induction of cell cycle arrested of encephalitogenic T cells. CNS is exceptionally sensitive to inflammation-caused damage since post mitotic neurons are incapable of regeneration and loss of neurons is associated with loss of vital functions imperative for survival of organism. Hence, neurons are equipped with delicate regulatory properties to limit inflammation of the CNS.
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| 18. |
- Liu, Yawei, et al.
(författare)
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Neuron-mediated generation of regulatory T cells from encephalitogenic T cells suppresses EAE.
- 2006
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Ingår i: Nature Medicine. - : Springer Science and Business Media LLC. - 1546-170X .- 1078-8956. ; 12:5, s. 518-525
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Tidskriftsartikel (refereegranskat)abstract
- Neurons have been neglected as cells with a major immune-regulatory function because they do not express major histocompatibility complex class II. Our data show that neurons are highly immune regulatory, having a crucial role in governing T-cell response and central nervous system (CNS) inflammation. Neurons induce the proliferation of activated CD4+ T cells through B7-CD28 and transforming growth factor (TGF)-beta1–TGF-beta receptor signaling pathways, resulting in amplification of T-cell receptor signaling through phosphorylated ZAP-70, interleukin (IL)-2 and IL-9. The interaction between neurons and T cells results in the conversion of encephalitogenic T cells to CD25+TGF-beta1+CTLA-4+FoxP3+ T regulatory (Treg) cells that suppress encephalitogenic T cells and inhibit experimental autoimmune encephalomyelitis. Suppression is dependent on cytotoxic T lymphocyte antigen (CTLA)-4 but not TGF-beta1. Autocrine action of TGF-beta1, however, is important for the proliferative arrest of Treg cells. Blocking the B7 and TGF-beta pathways prevents the CNS-specific generation of Treg cells. These findings show that generation of neuron-dependent Treg cells in the CNS is instrumental in regulating CNS inflammation.
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| 19. |
- Liu, Yawei, et al.
(författare)
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PD-L1 Expression by Neurons Nearby Tumors Indicates Better Prognosis in Glioblastoma Patients.
- 2013
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Ingår i: The Journal of Neuroscience. - 1529-2401. ; 33:35, s. 14231-14245
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Tidskriftsartikel (refereegranskat)abstract
- Glioblastoma multiforme (GBM) is the most aggressive form of brain tumor. In general, tumor growth requires disruption of the tissue microenvironment, yet how this affects glioma progression is unknown. We studied program death-ligand (PD-L)1 in neurons and gliomas in tumors from GBM patients and associated the findings with clinical outcome. Remarkably, we found that upregulation of PD-L1 by neurons in tumor-adjacent brain tissue (TABT) associated positively with GBM patient survival, whereas lack of neuronal PD-L1 expression was associated with high PD-L1 in tumors and unfavorable prognosis. To understand the molecular mechanism of PD-L1 signaling in neurons, we investigated PD-L1 function in cerebellar and cortical neurons and its impact on gliomas. We discovered that neuronal PD-L1-induced caspase-dependent apoptosis of glioma cells. Because interferon (IFN)-β induces PD-L1 expression, we studied the functional consequences of neuronal Ifnb gene deletion on PD-L1 signaling and function. Ifnb(-/-) neurons lacked PD-L1 and were defective in inducing glioma cell death; this effect was reversed on PD-L1 gene transfection. Ifnb(-/-) mice with intracerebral isografts survived poorly. Similar to the observations in GBM patients, better survival in wild-type mice was associated with high neuronal PD-L1 in TABT and downregulation of PD-L1 in tumors, which was defective in Ifnb(-/-) mice. Our data indicated that neuronal PD-L1 signaling in brain cells was important for GBM patient survival. Reciprocal PD-L1 regulation in TABT and tumor tissue could be a prognostic biomarker for GBM. Understanding the complex interactions between tumor and adjacent stromal tissue is important in designing targeted GBM therapies.
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| 20. |
- Liu, Yawei, et al.
(författare)
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Suppression of EAE by oral tolerance is independent of endogenous IFN-beta whereas treatment with recombinant IFN-beta ameliorates EAE.
- 2010
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Ingår i: Immunology and Cell Biology. - : Wiley. - 1440-1711 .- 0818-9641. ; 88, s. 468-476
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Tidskriftsartikel (refereegranskat)abstract
- IFN-beta is anticipated to have an important function in mucosal tolerance, as it is one of the major cytokines produced by plasmacytoid dendritic cells, and has recently been suggested as central to the maintenance of mucosal homeostasis. Here, we have investigated whether oral tolerance is dependent on endogenous IFN-beta by feeding low-dose self-antigen myelin basic protein to IFN-beta(-/-) mice with subsequent induction of experimental autoimmune encephalomyelitis (EAE). Our study shows that oral tolerance was readily induced in IFN-beta(-/-) mice compared with their wild-type littermates (IFN-beta(+/+)). The non-self-antigen ovalbumin induced oral tolerance in both groups. These data indicate that endogenous IFN-beta is not required for induction of oral tolerance, whereas delivery of recombinant IFN-beta results in significant reduction in clinical score of EAE. Oral tolerance induction was associated with lower production of antigen-specific IFN-gamma, no shift toward antigen-specific Th2, Th17 or TGF-beta response was observed. Oral tolerance in IFN-beta(-/-) mice was also associated with the induction of regulatory and memory T cells in the mucosal-associated immune organs, however this was not a prerequisite for establishment of oral tolerance.Immunology and Cell Biology advance online publication, 12 January 2010; doi:10.1038/icb.2009.111.
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| 21. |
- Liu, Yawei, 1967-, et al.
(författare)
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Time- and pH-dependent release of PDGF and TGF-ß from platelets in vitro
- 2003
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Ingår i: Platelets. - : Informa UK Limited. - 0953-7104 .- 1369-1635. ; 14:4, s. 233-237
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Tidskriftsartikel (refereegranskat)abstract
- We studied the spontaneous and thrombin-induced activation of platelets and their release of platelet-derived growth factor (PDGF) and transforming growth factor-β (TGF-β) at different pH values. Platelet activation was assayed with anti-bodies against P-selectin and performed in serum-free media. The release of PDGF and TGF-β was determined by ELISA after 15 min and 12 h. There was no activation at pH 5.0, while a time-dependent release of growth factors occurred at neutral and alkaline pH. The results suggest that release of growth factors is not only dependent on platelet activation but also on incubation time and pH. Although the used serum-free experimental situation is different from normal conditions for platelets in vivo, the findings of a late release of growth factors may, nevertheless, be relevant to wound healing.
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| 22. |
- Ruan, Ting, et al.
(författare)
-
Concentrations and composition profiles of benzotriazole UV stabilizers in municipal sewage sludge in China
- 2012
-
Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 46:4, s. 2071-2079
-
Tidskriftsartikel (refereegranskat)abstract
- The environmental contamination and fate of benzotriazole UV stabilizers (BZTs) have received increasing attention due to their large production volume and wide usage in various consumer and industrial products. In the present work, 60 municipal sewage sludge samples from wastewater treatment plants (WWTPs) in 33 cities in China were collected to investigate the occurrence and distribution of 9 frequently used BZTs. The most dominant analogue was 2-[3,5-bis(1-methyl-1-phenylethyl)-2-hydroxyphenyl]benzotriazole (UV-234) at a median concentration of 116 ng/g (dry weight) and accounted on average for 27.2% of total BZTs. The abundance was successively followed by 2-(2-hydroxy-5-tert-octylphenyl)benzotriazole (UV-329, average 24.3%), 2-(2-hydroxy-3-tert-butyl-5-methylphenyl)-5-chlorobenzotriazole (UV-326, average 22.2%), 2-(3,5-di-tert-amyl-2-hydroxyphenyl)benzotriazole (UV-328, average 17.7%), and 2-(2-hydroxy-5-methylphenyl)benzotriazole (UV-P, average 6.6%), with median concentrations of 66.8, 67.8, 57.3, and 20.6 ng/g, respectively. 5-Chloro-2-(3,5-di-tert-butyl-2-hydroxyphenyl)benzotriazole (UV-327) and 2-(3-sec-butyl-5-tert-butyl-2-hydroxyphenyl)benzotriazole (UV-350) had low detection frequency, while 2-(3,5-di-tert-butyl-2-hydroxyphenyl)benzotriazole (UV-320) and 2-(5-tert-butyl-2-hydroxyphenyl)benzotriazole (UV-PS) were not detectable in any sample. To our knowledge, this is the first study reporting the occurrence of UV-234, UV-329, and UV-350 in sewage sludge in China. Significant correlations were found among the BZT concentrations and also with a WWTP characteristic (daily treatment volume). Furthermore, results from degradation prediction and multimedia fate simulation based on a quantitative structure-property relationship (QSPR) model at screening level also implied that the commercial BZT chemicals and their plausible transformation products might be persistent in the environment.
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| 23. |
- Ruan, Ting, et al.
(författare)
-
Presence and partitioning behavior of polyfluorinated iodine alkanes in environmental matrices around a fluorochemical manufacturing plant : another possible source for perfluorinated carboxylic acids?
- 2010
-
Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 44:15, s. 5755-5761
-
Tidskriftsartikel (refereegranskat)abstract
- The indistinct origins of some ubiquitous perfluorinated alkyl acids have attracted great attention in recent decades. In this present work, even-chained polyfluorinated iodides (PFIs), a group of volatile perfluorinated compounds (PFCs), including four perfluorinated iodine alkanes (FIAs) and three polyfluorinated telomer iodides (FTIs) were confirmed to be present in the environment. A wide concentration range was found for FIAs at 1.41 to 3.08x104 pg/L, and for FTIs at 1.39 to 1.32x103 pg/L in the ambient air collected around a fluorochemical manufacturing plant in Shandong province, northern China. Whereas for surface soils, most of these PFIs were below detection limits and only small amounts of analytes with higher carbon chain (such as perfluorododecyl iodide and 1H,1H,2H,2H-perfluorodecyl iodide, 16.6-499 pg/g) could be sporadically detected. The presence of the PFIs in different environmental matrices in the investigated area and calculated vapor pressures (0.095-20.4 Torr) verify that they can be considered as volatile organic chemicals and easily be released into the atmosphere. Together with reported degradation ability and long-range transport potential, the identification of these PFIs indicates that unintentional release during the telomer reaction process might also be another route for the formation and distribution of certain polyfluorinated alcohols, aldehydes, and carboxylic acid derivatives under oxidative conditions in the environment.
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| 24. |
- Ruscher, Karsten, et al.
(författare)
-
Inhibition of CXCL12 signaling attenuates the postischemic immune response and improves functional recovery after stroke.
- 2013
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Ingår i: Journal of Cerebral Blood Flow and Metabolism. - : SAGE Publications. - 1559-7016 .- 0271-678X. ; 33:8, s. 1225-1234
-
Tidskriftsartikel (refereegranskat)abstract
- After stroke, brain inflammation in the ischemic hemisphere hampers brain tissue reorganization and functional recovery. Housing rats in an enriched environment (EE) dramatically improves recovery of lost neurologic functions after experimental stroke. We show here that rats housed in EE after stroke induced by permanent occlusion of the middle cerebral artery (pMCAO), showed attenuated levels of proinflammatory cytokines in the ischemic core and the surrounding peri-infarct area, including a significant reduction in the stroke-induced chemokine receptor CXCR4 and its natural ligand stromal cell-derived factor-1 (CXCL12). To mimic beneficial effects of EE, we studied the impact of inhibiting CXCL12 action on functional recovery after transient MCAO (tMCAO). Rats treated with the specific CXCL12 receptor antagonist 1-[4-(1,4,8,11-tetrazacyclotetradec-1-ylmethyl)phenyl]methyl]-1,4,8,11-tetrazacyclo-tetradecan (AMD3100) showed improved recovery compared with saline-treated rats after tMCAO, without a concomitant reduction in infarct size. This was accompanied by a reduction of infiltrating immune cells in the ischemic hemisphere, particularly cluster of differentiation 3-positive (CD3(+)) and CD3(+)/CD4(+) T cells. Spleen atrophy and delayed death of splenocytes, induced by tMCAO, was prevented by AMD3100 treatment. We conclude that immoderate excessive activation of the CXCL12 pathway after stroke contributes to depression of neurologic function after stroke and that CXCR4 antagonism is beneficial for the recovery after stroke.Journal of Cerebral Blood Flow & Metabolism advance online publication, 1 May 2013; doi:10.1038/jcbfm.2013.71.
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| 25. |
- Schindler, Seth, et al.
(författare)
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The Second Cold War: US-China Competition for Centrality in Infrastructure, Digital, Production, and Finance Networks
- 2023
-
Ingår i: Geopolitics. - 1465-0045 .- 1557-3028. ; , s. 1-38
-
Tidskriftsartikel (refereegranskat)abstract
- Relations between the US and China have deteriorated to their lowest point since their rapprochement in the 1970s. To make sense of contemporary geopolitics, our objective in this article is two-fold. First, we historically situate contemporary US-China rivalry to conceptualise the Second Cold War (SCW). We argue that in the wake of the 2008 financial crisis, both the US and China launched ‘restorative’ political projects that harked back to imagined pasts. These projects are mutually exclusive and animate contemporary geopolitics. Second, we conceptualise the spatial logic of great power rivalry in the Second Cold War. In contrast to the first Cold War, when great powers sought to incorporate territory into blocs, the US and China currently compete on a global scale for centrality in four interrelated networks that they anticipate will underpin hegemony in the 21st century: infrastructure (e.g. logistics and energy), digital, production and finance. We review the state of competition in each network and draw two broad conclusions: (1) this mode of competition makes it difficult for either side to conclusively ‘win’ the Second Cold War, and (2) many countries are likely to remain integrated with both the US and China.
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| 26. |
- Skibola, Christine F, et al.
(författare)
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Genome-wide Association Study Identifies Five Susceptibility Loci for Follicular Lymphoma outside the HLA Region.
- 2014
-
Ingår i: American Journal of Human Genetics. - : Elsevier BV. - 0002-9297 .- 1537-6605. ; 95:4, s. 462-471
-
Tidskriftsartikel (refereegranskat)abstract
- Genome-wide association studies (GWASs) of follicular lymphoma (FL) have previously identified human leukocyte antigen (HLA) gene variants. To identify additional FL susceptibility loci, we conducted a large-scale two-stage GWAS in 4,523 case subjects and 13,344 control subjects of European ancestry. Five non-HLA loci were associated with FL risk: 11q23.3 (rs4938573, p = 5.79 × 10(-20)) near CXCR5; 11q24.3 (rs4937362, p = 6.76 × 10(-11)) near ETS1; 3q28 (rs6444305, p = 1.10 × 10(-10)) in LPP; 18q21.33 (rs17749561, p = 8.28 × 10(-10)) near BCL2; and 8q24.21 (rs13254990, p = 1.06 × 10(-8)) near PVT1. In an analysis of the HLA region, we identified four linked HLA-DRβ1 multiallelic amino acids at positions 11, 13, 28, and 30 that were associated with FL risk (pomnibus = 4.20 × 10(-67) to 2.67 × 10(-70)). Additional independent signals included rs17203612 in HLA class II (odds ratio [ORper-allele] = 1.44; p = 4.59 × 10(-16)) and rs3130437 in HLA class I (ORper-allele = 1.23; p = 8.23 × 10(-9)). Our findings further expand the number of loci associated with FL and provide evidence that multiple common variants outside the HLA region make a significant contribution to FL risk.
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| 27. |
- Teige, Anna, et al.
(författare)
-
CD1d-dependent NKT cells play a protective role in acute and chronic arthritis models by ameliorating antigen-specific Th1 responses.
- 2010
-
Ingår i: Journal of immunology. - : The American Association of Immunologists. - 1550-6606 .- 0022-1767. ; 185:1, s. 345-356
-
Tidskriftsartikel (refereegranskat)abstract
- A protective and anti-inflammatory role for CD1d-dependent NKT cells (NKTs) has been reported in experimental and human autoimmune diseases. However, their role in arthritis has been unclear, with conflicting reports of CD1d-dependent NKTs acting both as regulatory and disease-promoting cells in arthritis. These differing modes of action might be due to genetic differences of inbred mice and incomplete backcrossing of gene-modified mice. We therefore put special emphasis on controlling the genetic backgrounds of the mice used. Additionally, we used two different murine arthritis models, Ag-induced arthritis (AIA) and collagen-induced arthritis (CIA), to evaluate acute and chronic arthritis in CD1d knockout mice and mice depleted of NK1.1(+) cells. CD1d-deficient mice developed more severe AIA compared with wild-type littermates, with a higher degree of inflammation and proteoglycan depletion. Chronic arthritis in CIA was also worse in the absence of CD1d-dependent NKTs. Elevated levels of Ag-specific IFN-gamma production accompanied these findings rather than changes in IL-17alpha. Depletion of NK1.1(+) cells supported these findings in AIA and CIA. This report provides support for CD1d-dependent NKTs being suppressor cells in acute and chronic arthritis, likely via inhibition of arthritogenic Th1 cells. These results make CD1d-dependent NKTs an attractive target for therapeutic intervention.
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| 28. |
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| 29. |
- Wang, Ling, et al.
(författare)
-
Perfluorooctanesulfonate Induces Hepatomegaly and Lipoatrophy in Mice through Phosphoenolpyruvate Carboxykinase-Mediated Glyceroneogenesis Inhibition
- 2020
-
Ingår i: Environmental Science and Technology Letters. - : American Chemical Society (ACS). - 2328-8930. ; 7:3, s. 185-190
-
Tidskriftsartikel (refereegranskat)abstract
- Perfluorooctansulfonate (PFOS) is a persistent organic pollutant that has attracted a great deal of attention due to toxic effects such as its lipid metabolism-disrupting potential. Exposure to PFOS can cause hepatomegaly and lipoatrophy in mice, but the underlying mechanisms are still unknown. Considering that glyceroneogenesis is the essential pathway for balancing the triglyceride (TG) cycle between liver and white adipose tissue (WAT), we speculate that PFOS acts via glyceroneogenesis inhibition to alter TG metabolism in the two tissues. Combining gene expression, protein expression, an enzyme activity assay, and molecular docking analysis, we report here that PFOS can interact with cytosolic phosphoenolpyruvate carboxykinase (PEPCK), the rate-limiting enzyme of glyceroneogenesis. Specifically, by repression of PEPCK, PFOS can inhibit the glyceroneogenesis process and thus decrease the glyceroneogenesis-derived glycerol level, leading to a reduced re-esterified TG level and causing atrophy in WAT. Moreover, in PFOS-exposed liver tissue, despite the fact that free glycerol and fatty acids released from WAT were being used for TG synthesis, the export of TG slowed. This eventually resulted in the continuous lipolysis of WAT and accumulation of lipid in the liver. PEPCK can be used as a key biomarker to assess the lipid metabolism disorders induced by other conventional and emerging per- and polyfluoroalkyl substances.
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| 30. |
- Wang, Yawei, et al.
(författare)
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Quantitative structure-activity relationship for prediction of the toxicity of polybrominated diphenyl ether (PBDE) congeners
- 2006
-
Ingår i: Chemosphere. - : Elsevier BV. - 0045-6535 .- 1879-1298. ; 64:4, s. 515-524
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Tidskriftsartikel (refereegranskat)abstract
- Levels of Polybrominated diphenyl ether (PBDEs) are increasing in the environment due to their use as flame retardants. The similarities of structure to polychlorinated biphenyl (PCB) congeners suggest that they may share similar toxicological properties, such as hepatic enzyme induction. In this work, quantitative structure-activity relationship (QSAR) models were constructed based on 406 descriptors for the logarithm of toxicology index (aryl hydrocarbon receptor relative binding affinities, AhR, I) of 18 PBDE congeners. The method used for building model is the Heuristic method, which is included in comprehensive descriptors for structural and statistical analysis (CODESSA) software. The best regression model involved four descriptors, which were related to the conformational changes, atomic reactivity, molecular electrostatic field, and non-uniformity of mass distribution in a molecule of PBDEs, etc. The high square of the correlation coefficient R(2)(0.903) showed the model was satisfactory.
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| 31. |
- Yang, Weijin, et al.
(författare)
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Alterations of endogenous metabolites in urine of rats exposed to decabromodiphenyl ether using metabonomic approaches
- 2014
-
Ingår i: Journal of Environmental Sciences(China). - : Elsevier. - 1001-0742 .- 1878-7320. ; 26:4, s. 900-908
-
Tidskriftsartikel (refereegranskat)abstract
- There is large usage of polybrominated diphenyl ethers (PBDEs) especially for decabromodiphenyl ether (BDE-209, Deca-BDE) in controlling the risks of fire. The toxicological effects of PBDEs are worth being concerned about. Female SD rats were daily gavaged with BDE-209 ether at the dose of 100 mg/kg for 20 days. Histological observation was performed for the screening of the target organs for BDE-209 exposure. The distribution and metabolism of PBDEs in the exposed main organs were evidenced by HRGC-HRMS. Alterations of the endogenous metabolite concentrations in urine were investigated using metabonomic approaches based on (1)H NMR spectrum. Histopathological changes including serious edema in kidney, hepatocellular spotty necrosis and perivasculitis in liver indicated that BDE-209 caused potential influences on endogenous metabolism in the exposed liver and the kidney. BDE-209 was found to be highly accumulated in lipid, ovary, kidney and liver after 20 days' exposure. Occurrence of other lower brominated PBDEs in the rats demonstrated that reductive debromination process happened in vivo. Hydroxylated and methoxylated-BDEs, as metabolism products, were also detected in the rat tissues. A total of 12 different endogenous metabolites showed obvious alterations in urine from the exposed rats, indicating the disturbance of the corresponding internal biochemical processes induced by BDE-209 exposure. These findings in vivo suggested the potential health risk might be of concern due to the toxicological effects of BDE-209 as a ubiquitous compound in the environment.
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| 32. |
- Yang, Wenxing, et al.
(författare)
-
Harvesting Sub-Bandgap IR Photons by Photothermionic Hot Electron Transfer in a Plasmonic p-n Junction
- 2021
-
Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6984 .- 1530-6992. ; 21:9, s. 4036-4043
-
Tidskriftsartikel (refereegranskat)abstract
- Plasmonic semiconductors are an emerging class of low-cost plasmonic materials, and the presence of a bandgap and band-bending in these materials offer new opportunities to overcome some of the limitations of plasmonic metals. Here, we demonstrate that in a plasmonic p-n heterojunction (Cu2-xSe-CdSe) the near-IR excitation (1.1 eV) of the hole plasmon in the p-Cu2-xSe phase results in rapid hot electron transfer to n-CdSe, with an energy 2.2 eV above the Fermi level. This hot electron generation and energy upconversion process can be well-described by a photothermionic mechanism, where the presence of a bandgap in p-Cu2-xSe facilitates the generation of energetic photothermal electrons. The lifetime of the transferred electrons in Cu2-xSe-CdSe can reach similar to 130 ps, which is nearly 100x longer than that of its metal-semiconductor counterpart. This result demonstrates a novel approach for harvesting the sub-bandgap near IR photons using plasmonic p-n junctions and the potential advantages of plasmonic semiconductors for hot carrier-based devices.
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| 33. |
- Yang, Wenxing, et al.
(författare)
-
Photoinduced Fano Resonances between Quantum Confined Nanocrystals and Adsorbed Molecular Catalysts
- 2021
-
Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6984 .- 1530-6992. ; 21:13, s. 5813-5818
-
Tidskriftsartikel (refereegranskat)abstract
- Interaction of surface adsorbate vibration and intraband electron absorption in nanocrystals has been reported to affect the photophysical properties of both nanocrystals and surface adsorbates and may affect the performance of hybrid photocatalysts composed of semiconductor nanocrystals and molecular catalysts. Here, by combining ultrafast transient visible and IR spectroscopic measurements, we report the observation of Fano resonances between the intraband transition of the photogenerated electrons in CdS and CdSe nanocrystals and CO stretching vibrational modes of adsorbed molecular catalysts, [Fe-2(cbdt)(CO)(6)] (FeFe; cbdt = 1-carboxyl-benzene-2,3-dithiolate), a molecular mimic for the active site of FeFe-hydrogenase. The occurrence of Fano resonances is independent of nanocrystal types (rods vs dots) or charge transfer character between the nanocrystal and FeFe, and is likely a general feature of nanocrystal and molecular catalyst hybrid systems. These results provide new insights into the fundamental interactions in these hybrid assemblies for artificial photosynthesis.
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| 34. |
- Yang, Wenxing, et al.
(författare)
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Ultrafast and Long-Lived Transient Heating of Surface Adsorbates on Plasmonic Semiconductor Nanocrystals
- 2021
-
Ingår i: Nano letters (Print). - : American Chemical Society (ACS). - 1530-6984 .- 1530-6992. ; 21:1, s. 453-461
-
Tidskriftsartikel (refereegranskat)abstract
- Plasmonic photocatalysts have demonstrated promising potential for enhancing the selectivity and efficiency of important chemical transformations. However, the relative contributions of nonphotothermal (i.e., hot carrier) and photothermal pathways remain a question of intense current debate, and the time scale and extent of surface adsorbate temperature change are still poorly understood. Using p-type Cu2-xSe nanocrystals as a semiconductor plasmonic platform and adsorbed Rhodamine B as a surface thermometer and hot carrier acceptor, we measure directly by transient absorption spectroscopy that the adsorbate temperature rises and decays with time constants of 1.4 +/- 0.4 and 471 +/- 126 ps, respectively, after the excitation of Cu2-xSe plasmon band at 800 nm. These time constants are similar to those for Cu2-xSe lattice temperature, suggesting that fast thermal equilibrium between the adsorbates and nanocrystal lattice is the main adsorbate heating pathway. This finding provides insights into the transient heating effect on surface adsorbates and their roles in plasmonic photocatalysis.
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| 35. |
- Yu, Miao, et al.
(författare)
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Structure prediction of methyoxy-polybrominated diphenyl ethers (MeO-PBDEs) through GC-MS analysis of their corresponding PBDEs
- 2016
-
Ingår i: Talanta. - Amsterdam, Netherlands : Elsevier. - 0039-9140 .- 1873-3573. ; 152, s. 9-14
-
Tidskriftsartikel (refereegranskat)abstract
- It is hard to quantify the trace pollutants in the environment without the corresponding reference standards. Structure identifications of unknown organic pollutants are thus of great importance in environmental analysis. As for polybrominated diphenyl ethers (PBDE) with one substituent of methoxyl group, there are 837 congeners, but only 32 standards are commercially available. In this work, an effective method based on gas chromatography coupled with mass spectrometry (GC-MS) was proposed to predict the potential structures of methoxylated polybrominated diphenyl ethers (MeO-PBDEs). The mass fragmentation pattern using SIM mode not only provided the useful information on the substitution position of methoxyl group, the number of Br atoms, but also guaranteed the high sensitivity for trace analysis. Br distribution patterns of the unknown MeO-PBDEs were revealed by a linear regression model with dummy variables which described the retention time relationship between MeO-PBDEs and the corresponding PBDEs on different types of GC columns. This method was successfully used to identify three new MeO-PBDEs metabolites of BDE-28 as 4-MeO-BDE-22, 4'-MeO-BDE-25 and 4-MeO-BDE-31 in the pumpkins. Therefore, the newly developed structure prediction model based on GC-MS behavior is helpful in the evaluation of unknown PBDE metabolites in the environment.
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| 36. |
- Yu, Yawei, et al.
(författare)
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Ferromagnetism with in-plane magnetization, Dirac spin-gapless semiconducting properties, and tunable topological states in two-dimensional rare-earth metal dinitrides
- 2022
-
Ingår i: Physical Review B. - : American Physical Society. - 2469-9950 .- 2469-9969. ; 105:2
-
Tidskriftsartikel (refereegranskat)abstract
- Since the successful synthesis of bulk single crystals MoN2 and ReN2, which have a layered structure, transition-metal dinitrides have attracted considerable attention in recent years. Here, we focus on rare-earth metal (Rem) elements, and propose seven stable Rem dinitride monolayers with a 1T structure, namely, 1T-RemN2. We use first-principles calculations, and find that these monolayers have a ferromagnetic ground state with in-plane magnetization. Without spin-orbit coupling (SOC), the band structures are spin-polarized with Dirac points at the Fermi level. Remarkably, the 1T-LuN2 monolayer exhibits an isotropic magnetocrystalline anisotropy energy in the xy plane with in-plane magnetization, indicating easy tunability of the magnetization direction. When rotating the magnetization vector in the xy plane, we propose a model that accurately describes the variation of the SOC band gap and the two possible topological states (Weyl-like semimetal and Chern insulator states) whose properties are tunable. The Weyl-like semimetal state is a critical point between the two Chern insulator states with opposite sign of the Chern numbers (+/- 1). The nontrivial band gap (up to 60.3 meV) and the Weyl-like semimetal state are promising for applications in spintronic devices.
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| 37. |
- Zeng, Lixi, et al.
(författare)
-
Distribution and trophic transfer of short-chain chlorinated paraffins in an aquatic ecosystem receiving effluents from a sewage treatment plant
- 2011
-
Ingår i: Environmental Science and Technology. - Washington, USA : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 45:13, s. 5529-5535
-
Tidskriftsartikel (refereegranskat)abstract
- Short-chain chlorinated paraffins (SCCPs) are an extremely complex group of industrial chemicals and found to be potential persistent organic pollutants (POPs), and thus have attracted extensive concern worldwide. In this study, influent, effluent, and sludge were collected from a large sewage treatment plant (STP) in Beijing, China. Water, sediment, and aquatic species were also collected from a recipient lake that receives effluents discharged from the STP. These samples were then analyzed to investigate the effect of STP effluent on distribution and trophic transfer of SCCPs in the local aquatic ecosystem. Concentrations of total SCCPs (ΣSCCPs) in lake water and surface sediments were found in the range 162-176 ng/L and 1.1-8.7 μg/g (dry weight, dw), respectively. Vertical concentration profiles of sediment cores showed ΣSCCPs decreased exponentially with increasing depth. Specific congener composition analysis in sediment layers indicated possible in situ biodegradation might be occurring. High bioaccumulation of SCCPs was observed in the sampled aquatic species. The bioaccumulation factor (BAF) generally increased with the number of chlorines in the SCCP congeners. A significantly positive correlation between lipid-normalized ΣSCCPs concentration and trophic levels (R(2) = 0.65, p < 0.05) indicate that SCCPs can biomagnify through the food chain in the effluent-receiving aquatic ecosystem.
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| 38. |
- Zeng, Lixi, et al.
(författare)
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Distribution of short chain chlorinated paraffins in marine sediments of the East China Sea : influencing factors, transport and implications
- 2012
-
Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 46:18, s. 9898-9906
-
Tidskriftsartikel (refereegranskat)abstract
- Short chain chlorinated paraffins (SCCPs) are high production volume chemicals in China and found to be widely present in the environment. In this study, fifty-one surface sediments and two sediment cores were collected from the East China Sea to study their occurrence, distribution patterns and potential transport in the marginal sea. SCCPs were found in all surface sediments and ranged from 5.8 to 64.8 ng/g (dry weight, d.w.) with an average value of 25.9 ng/g d.w. A general decreasing trend with distance from the coast was observed, but the highest value was found in a distal mud area far away from the land. The C10 homologue was the most predominant carbon chain group, followed by C11, C12, and C13 homologue groups. Significant linear relationship was found between total organic carbon (TOC) and total SCCP concentrations (R(2) = 0.51, p < 0.05). Spatial distributions and correlation analysis indicated that TOC, riverine input, ocean current, and atmospheric deposition played an important role in controlling SCCP accumulation in marine sediments. Vertical profiles of sediment cores showed that SCCP concentrations decreased from surface to the depth of 36 cm, and then slightly increased again with depth, which showed a significant positive correlation with TOC and chlorine contents (Cl%). The results suggest that SCCPs are being regionally or globally distributed by long-range atmospheric or ocean current transport.
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| 39. |
- Zeng, Lixi, et al.
(författare)
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Levels and distribution patterns of short chain chlorinated paraffins in sewage sludge of wastewater treatment plants in China
- 2012
-
Ingår i: Environmental Pollution. - : Elsevier BV. - 0269-7491 .- 1873-6424. ; 160:1, s. 88-94
-
Tidskriftsartikel (refereegranskat)abstract
- Short chain chlorinated paraffins (SCCPs) are listed as persistent organic pollutant candidates in the Stockholm Convention and are receiving more and more attentions worldwide. In general, concentrations of contaminants in sewage sludge can give an important indication on their pollution levels at a local/regional basis. In this study, SCCPs were investigated in sewage sludge samples collected from 52 wastewater treatment plants in China. Concentrations of total SCCPs (ΣSCCPs) in sludge were in the range of 0.80-52.7 μg/g dry weight (dw), with a mean value of 10.7 μg/g dw. Most of SCCPs in the sludge samples showed a similar congener distribution patterns, and C(11) and Cl(7,8) were identified as the dominant carbon and chlorine congener groups. Significant linear relationships were found among different SCCP congener groups (r(2) ≥ 0.9). High concentrations of SCCPs in sewage sludge imply that SCCPs are widely present in China.
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| 40. |
- Zeng, Lixi, et al.
(författare)
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Spatial and vertical distribution of short chain chlorinated paraffins in soils from wastewater irrigated farmlands
- 2011
-
Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 45:6, s. 2100-2106
-
Tidskriftsartikel (refereegranskat)abstract
- Chlorinated paraffins (CPs) are one of the most complex groups of halogenated contaminants in the environment. However, studies of short chain CPs (SCCPs) in China are very scarce. In this study, the concentrations and distribution of SCCPs in farm soils from a wastewater irrigated area in China were investigated. SCCPs were detected in all topsoil samples, with the sum of the concentrations (ΣSCCPs) in the range of 159.9-1450 ng/g (dry weight, dw). A noticeable spatial trend and specific congener distribution were observed in the wastewater irrigated farmland. Soil vertical profiles showed that ΣSCCP concentrations below the plowed layer decreased exponentially and had a significant positive relationship (R(2) > 0.83) with total organic carbon in soil cores. Furthermore, soil vertical distributions indicated that lower chlorinated (Cl(5-6)) and shorter chain (C(10-12)) congeners are more prone to migrate to deeper soil layers compared to highly chlorinated and longer chain congeners. This work demonstrated that effluents from sewage treatment plants (STPs) could be a significant source of SCCPs to the ambient environment and wastewater irrigation can lead to higher accumulation of SCCPs in farm soils.
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| 41. |
- Zhang, Haiyan, et al.
(författare)
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Levels and distributions of hexachlorobutadiene and three chlorobenzenes in biosolids from wastewater treatment plants and in soils within and surrounding a chemical plant in China.
- 2014
-
Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 48:3, s. 1525-1531
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Tidskriftsartikel (refereegranskat)abstract
- Although hexachlorobutadiene (HCBD) was recently proposed as a candidate persistent organic pollutant (POP) under the Stockholm Convention, information about its environmental levels and distributions is still very limited. In this work, HCBD was determined in the sewage sludge from 37 wastewater treatment plants (WWTPs) in 23 cities and 17 soils near a chemical plant in China. Three chlorobenzenes (CBs) (1,2,4-trichlorobenzene, 1,2,4,5-tetrachlorobenzene, and hexachlorobenzene) were simultaneously studied to help better understand the environmental behavior of HCBD. Concentrations of HCBD in sludge samples ranged from <0.03 to 74.3 ng/g dry weight (dw) with a median value of 0.30 ng/g dw, which was lower than those of the three CBs. Levels of HCBD were not correlated with capacity of the WWTPs and total organic carbon. For soils, high level of HCBD was found in the sample within the plant, with a rapid decreasing concentration trend with the increase of distance from the plant. It was suspected that releasing as a byproduct during manufacturing of chlorinated chemicals was the primary source of HCBD in the studied location. Further risk assessment indicated that the environmental risk of HCBD to soil organisms and the health risk to employees were very low through soil exposure within the plant.
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| 42. |
- Zhao, Ming, et al.
(författare)
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Activation of the p38 MAP kinase pathway is required for foam cell formation from macrophages exposed to oxidized LDL
- 2002
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Ingår i: Acta Pathologica, Microbiologica et Immunologica Scandinavica (APMIS). - : Wiley. - 0903-4641 .- 1600-0463. ; 110:6, s. 458-468
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Tidskriftsartikel (refereegranskat)abstract
- Endocytosis of oxidized low density lipoproteins (oxLDL) by macrophages, mediated by scavenger receptors, is thought to play a central role in foam cell formation and, thus, in the pathogenesis of atherosclerosis. OxLDL activates several MAP kinases, including the ERK, JNK and p38 MAP kinases, but the role of these activations in oxLDL uptake has not been studied. In the present investigation, we find that SB203580, a specific inhibitor of p38, blocks oxLDL-exposed J774 cells from becoming foam cells. Inhibition of foam cell formation by blockade of the p38 pathway is, at least in part, due to inhibition of oxLDL-induced up-regulation of the scavenger receptor CD36. Using pharmaceutical inhibitors and dominant active MAP kinase kinases, we demonstrated that activation of the p38 pathway, but not the ERK or JNK pathways, is necessary and sufficient to transactivate PPAR?, a nuclear receptor that has recently been shown to play a pivotal role in oxLDL-induced CD36 expression. Our results for the first time demonstrate a regulation of CD36 by p38, and the importance of the p38 pathway in regulation of foam cell formation.
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| 43. |
- Zhao, Ming, 1966-, et al.
(författare)
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Vascular smooth muscle cell proliferation requires both p38 and BMK1 MAP kinases
- 2002
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Ingår i: Archives of Biochemistry and Biophysics. - 0003-9861 .- 1096-0384. ; 400:2, s. 199-207
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Tidskriftsartikel (refereegranskat)abstract
- Vascular smooth muscle cell (VSMC) proliferation is a key event in the progression of atherosclerosis. Induction of both c-fos (through the transcription factor Elk-1) and c-jun, both immediate early genes, is important for the stimulation of VSMC proliferation and migration. It was earlier found that p38 mitogen-activated protein (MAP) kinase upregulates c-jun gene transcription through phosphorylation of two myocyte enhancer factor 2 (MEF2) family transcription factors, MEF2A and MEF2C, while big MAP kinase 1 (BMK1) may upregulate c-jun gene transcription through MEF2A, MEF2C, and also MEF2D. Here, we report that inhibition of BMK1 by a dominant negative form of MEK5 or pharmacologic inhibition of p38 by SB 203580 additively suppress serum-induced VSMC proliferation. This additive effect of p38 and BMK1 inhibition implies that these two kinases coordinately regulate MEF2 transcription factors. The exclusive activation of MEF2D by BMK1 appears required for this cooperative upregulation of c-jun in VSMC, and coactivation of p38 and BMK1 also has additive effects on the activation of a reporter gene linked to the c-jun promoter in our experimental system. Thus, coordinate activity of both the p38 and BMK1 pathways appears necessary for optimal transcription of c-jun and, pari pasu, VSMC proliferation. These results may have implications for the future design of pharmacologic agents for inhibition of VSMC growth.
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| 44. |
- Zhao, Yawei, et al.
(författare)
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Fine-tuning the coordination atoms of copper redox mediators : an effective strategy for boosting the photovoltage of dye-sensitized solar cells
- 2019
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Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry. - 2050-7488 .- 2050-7496. ; 7:20, s. 12808-12814
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Tidskriftsartikel (refereegranskat)abstract
- Natural systems have marvelously utilized copper complexes featuring sulfur-coordinating ligands, known as blue copper proteins, as efficient electron-transfer mediators in biological processes. Copper complexes with sulfur-coordinating ligands have been attempted as redox mediators in dye-sensitized solar cells (DSCs), the performance of which is not yet satisfactory and still remains less well explored. Herein, we report the application of new copper complexes bearing a tetradentate polythioether ligand, [(S-4)Cu](2+/+) (1(2+/+), S-4 = 1,4,8,11-tetrathiocyclotetradecane), as a redox mediator in DSCs in comparison with its N-4-tetradentate counterpart [(N-4)Cu](2+/+) (2(2+/+), N-4 = 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane). Impressively, the changes of coordination atoms from N to S positively shift the formal redox potential of the copper complexes by 600 mV, leading to a remarkably high photovoltage approaching 1.0 V. This is one of the highest photovoltage values reported thus far for DSCs based on copper redox mediators.
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| 45. |
- Zhu, Minggu, et al.
(författare)
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Dietary Mustard Seeds (Sinapis alba Linn) Suppress 1,2-Dimethylhydrazine-Induced Immuno-Imbalance and Colonic Carcinogenesis in Rats
- 2012
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Ingår i: Nutrition and Cancer. - : Taylor and Francis (Routledge): STM, Behavioural Science and Public Health Titles / Taylor and Francis (Routledge). - 0163-5581 .- 1532-7914. ; 64:3, s. 464-472
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Tidskriftsartikel (refereegranskat)abstract
- In a Wistar rat model, prolonged supplementation of mustard seed (MS) to the diet significantly ameliorates the induction of colorectal carcinomas by 1,2-dimethylhydrazine (DMH). The expression of the splenocyte major histocompatibility complex class I (MHCI) was found significantly enhanced, whereas that of the major histocompatibility complex class II (MHCII) was significantly decreased. Compared to that of control animals, the proportion of spleenic B- and dendritic cells (DC) was amplified in the MS group. The expressions of MHCI, as well as that of MHCII, were increased in DC cells; whereas in B cells, MHCI expression was augmented but that of MHCII moderately decreased. The percentages of CD8+CD28+ and CD4+CD28+ cells were increased in the MS group, while the CD4+CD25+Foxp3+ subset was depressed. Plasma analysis showed that DMH-exposure induced amplified amounts of interleukin (IL)-4, IL-5, IL-10, and transforming growth factor-beta, whereas MS feeding counteracted this effect but enhanced IL-2,IL12p70,IL21, TNF-alpha, and interferon-gamma. In the SW480 colon adenocarcinoma cell-line, the cytotoxicity of spleenic T-cells from MS-fed animals was significantly increased. In the DMH-exposed rats, the expression of perforin in the spleenic T-cells was dramatically decreased, whereas MS abolished this depression. In summary, dietary MS suppresses DMH-induced immuno-imbalance as well as colon carcinogenesis in rats.
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