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1.
Protein Pept Lett ; 2020 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-32370699

RESUMO

BACKGROUND: Antibacterial peptides play important roles in the innate immune system of insects and are divided into four categories according to their structures. Although many antibacterial peptides have been reported in lepidopteran insects, the roles of an attacin-like gene in immune response of Antheraea pernyi remain unclear. OBJECTIVE: In this study, the cloning and immunological functions of an attacin-like gene from Antheraea pernyi were investigated. METHODS: In this article, the open reading frame of Ap-attacin-like gene was cloned by PCR using the specific primers and then was ligated to the pET-32a vector to construct the recombinant plasmids Apattacin-like-pET-32a. The recombinant Ap-attacin-like protein was expressed in E. coli (BL21 DE3) cells and purified by Ni-NTA affinity chromatography. The expression patterns of Ap-attacin-like in different tissues or under microorganism challenges were investigated by real-time PCR and western blotting. Finally, agar well diffusion assay was performed to determine the antimicrobial activity of the recombinant Ap-attacin-like proteins based on the inhibition rate. RESULTS: The expression level of Ap-attacin-like was highest in the fat body compared with the other examined tissues. The expression of Ap-attacin-like in the fat body was significantly elevated after E. coli, Beauveria bassiana, Micrococcus luteus or nuclear polyhedrosis virus challenges. In addition, the recombinant Ap-attacin-like proteins had obvious antibacterial activity against E. coli. CONCLUSION: Ap-attacin-like was highly expressed in immune-related tissues and its expression level was significantly induced by different microorganism challenges, suggesting that Ap-attacin-like participated in the innate immunity of A. pernyi.

2.
Curr Neurovasc Res ; 2020 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-32370714

RESUMO

BACKGROUND: Myocardial fibrosis (MF) is an important physiological change after myocardial infarction (MI). MicroRNA-26b (MiR-26b) has a certain inhibitory effect on pulmonary fibrosis. However, the role of miR-26b in MI-induced MF rats and underlying molecular mechanisms remain unknown. MATERIAL AND METHODS: Forty male Sprague Dawley (SD) rats weighing 200-250g were divided into four groups (n=10): Sham group, MF group, MF + negative control (NC) agomir group and MF+miR-26b agomir group. Cardiac fibroblasts were isolated from cardiac tissue. Fibrosis levels were detected by MASSON staining, while expression of related genes was detected by RT-qPCR, Western blotting and Immunohistochemistry, respectively. TargetScan and dual luciferase reporter assay were utilized to predict the relationship between miR-26b and high mobility group, AT-hook 2 (HMGA2). RESULTS: Study found expression of miR-26b was down-regulated in myocardium of MF rats (p < 0.01). miR-26b overexpression in vitro significantly reduced survival rate of cardiac fibroblasts and inhibited expression of fibrillar-associated protein (α-SMA alpha-smooth muscle actin (α-SMA) and collagen I) (p < 0.01). TargetScan indicated that HMGA2 was one of the target genes of miR-26b, dual luciferase reporter assay further confirmed the targeted regulatory relationship (p < 0.01). Moreover, miR-26b overexpression significantly reduced the expression of HMGA2 (p < 0.01). Notably, HMGA2 overexpression reversed the inhibitory effect of miR-26b overexpression on cardiac fibroblast viability and the expression of α-SMA and collagen I (p < 0.01). Animal experiments further indicated that miR-26b overexpression inhibited MI-induced rat MF by inhibiting the expression of HMGA2 (p < 0.05, p < 0.01). CONCLUSION: In short, these findings indicate miR-26b targets HMGA2 to ameliorate MI-induced fibrosis by suppression cardiac fibroblasts activation.

3.
Macromol Rapid Commun ; : e2000123, 2020 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-32400926

RESUMO

Substituted naphthalimide (NI) moieties are highly versatile and newly recognized aggregation-induced emission (AIE) building blocks for many potentially useful smart molecules, polymers, and nanoparticles. However, the introduction of NI fluorophore into cross-linked polymeric networks to prepare AIE-active hydrogels still remains underdeveloped. Herein, a novel naphthalimide-based aggregation-induced emissive polymeric hydrogel is reported, followed by its proof-of-concept applications as fluorescence pattern switch and biomimetic actuator. The hydrogel, bearing semi-interpenetrating polymer networks, is synthesized starting from N-isopropylacrylamide, hydroxyethyl methacrylate, and a newly designed NI monomer (4-phenoxy-N-allyl-1,8-naphthalimide, PhAN). Rational molecular design for AIE-active PhAN monomer lies in modification of the NI core with rigid and bulky phenoxy group to break its planarity to produce desirable propeller-shaped molecular conformation. The as-prepared hydrogel is proved to be a aggregation-induced blue-light-emitting hydrogel. It also shows volume phase transition behavior and is endowed with thermally responsive synergistic emission and transmittance change, thus enabling simultaneous regulation of two optical properties merely by one single stimulus. These useful advantages further encourage fabrication of several proto-type fluorescence pattern switching and biomimetic actuating devices. This study may not only enlarge the list of fluorescent hydrogels but also serve as a novel smart optical platform for potential anticounterfeiting, sensing, displaying, or actuating applications.

4.
Food Chem ; 326: 126969, 2020 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-32438229

RESUMO

Biocompatible magnetic molecularly imprinted polymers (BMMIPs) were prepared with Zein for the first time, and were used to enrich tetracycline compounds selectively. Innovative combination of BMMIPs and electrochemistry to obtain lower detection line to satisfy industrial detection demands. Using Zein as the crosslinking agent, the polymers were synthesized on the surface of Fe3O4 particles. The scanning electron microscope, transmission electron microscope and X-ray diffraction technologies were used to characterize BMMIPs. Through optimization, BMMIPs attained large adsorption capacity (236.40 mg/g) with fast kinetics (40 min) and followed the Langmuir isotherm and pseudo-second-order kinetic models. BMMIPs had good recognition ability, the selective factors of oxytetracycline, chlortetracycline, doxycycline were 4.78, 4.23, and 3.39, respectively. Excellent linearity was attained in the range of 0.025-500 µg/mL, with low detection limits and low quantitation limits of 0.025 and 0.083 µg/mL. According to our exploring, BMMIPs was ideal materials for enrichment of tetracycline in complex biological samples.

5.
J Mol Diagn ; 2020 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-32302779

RESUMO

The results of EML4-ALK testing are critical to manage ALK inhibitor treatment. Thus, the accurate detection of ALK rearrangement is increasingly becoming a matter of serious concern. To address this issue, a long-term EML4-ALK proficiency testing (PT) scheme was launched in China since 2015, serving as an educational tool for assessing and improving the testing quality of EML4-ALK fusion detection. Responses across 20 different PT samples interrogating 3 different variants and wild-type samples were collected between 2015 and 2019. Performance was analyzed by evaluating the detection methods, kits, and pre-analytic practices used in order to further display the landscape of changing conditions of the reliability of EML4-ALK testing. During the five years, 3,224 results reported from 988 laboratories were evaluated, with an overall error rate of 5.36%. Along with an increasing number of participating laboratories, the error rate within each of the different methodologies showed a significantly downward trend over the years. No obvious differences in the error rates were found regarding the testing methods or kit manufacturers. Moreover, the individual performance of the laboratories improved when they participated in more PT scheme rounds. The data demonstrated that the performance of individual Chinese laboratories for EML4-ALK testing continuously improved over time by participating PT schemes, regardless of their methodology. However, care must be taken in standardized operations and validations.

6.
Brain Behav Immun ; 2020 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-32335193

RESUMO

Ubiquitin-specific protease 8 (USP8) regulates inflammation in vitro; however, the mechanisms by which USP8 inhibits neuroinflammation and its pathophysiological functions are not completely understood. In this study, we aimed to determine whether USP8 exerts neuroprotective effects in a mouse model of lipopolysaccharide (LPS)-induced cognitive and motor impairment. We commenced intracerebroventricular USP8 administration 7 days prior to i.p. injection of LPS (750 µg/kg). All treatments and behavioral experiments were performed once per day for 7 consecutive days. Behavioral tests and pathological/biochemical assays were performed to evaluate LPS-induced hippocampal damage. USP8 attenuated LPS-induced cognitive and motor impairments in mice. Moreover, USP8 downregulated several pro-inflammatory cytokines [nitric oxide (NO), tumor necrosis factor α (TNF-α), prostaglandin E2 (PGE2), and interleukin-1ß (IL-1ß)] in the serum and brain, and the relevant protein factors [inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX-2)] in the brain. Furthermore, USP8 upregulated the anti-inflammatory mediators interleukin (IL)-4 and IL-10 in the serum and brain, and promoted a shift from pro-inflammatory to anti-inflammatory microglial phenotypes. The LPS-induced microglial pro-inflammatory phenotype was abolished by TLR4 inhibitor and in TLR4-/- mice; these effects were similar to those of USP8 treatment. Mechanistically, we found that USP8 increased the expression of neuregulin receptor degradation protein-1 (Nrdp1), potently downregulated the expression of TLR4 and myeloid differentiation primary response protein 88 (MyD88) protein, and inhibited the phosphorylation of IκB kinase (IKK) ß and kappa B-alpha (IκBα), thereby reducing nuclear translocation of p65 by inhibiting the activation of the nuclear factor-kappaB (NF-κB) signaling pathway in LPS-induced mice. Our results demonstrated that USP8 exerts protective effects against LPS-induced cognitive and motor deficits in mice by modulating microglial phenotypes via TLR4/MyD88/NF-κB signaling.

7.
J Clin Lab Anal ; : e23256, 2020 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-32118319

RESUMO

BACKGROUND: To meet the requirements of the rapidly progressing genetic testing technologies in clinical laboratories, assuring the quality of genetic tests by utilizing appropriate quality control materials is of paramount importance. The CRISPR/Cas9 technology was used to prepare quality control materials because genome-edited human cell lines are one of the major resources for quality control materials. METHODS: In this study, in vitro transcribed sgRNA were transfected into a Cas9-expressing lymphoblastoid cell line (LCL)-by electroporation-to simulate the SEA-type deletion observed in α-thalassemia. The edited positive cell line was screened and identified by polymerase chain reaction (PCR) followed by Sanger sequencing. The whole-genome sequencing was also performed to show evidence of predicted mutation. RESULTS: The results showed that electroporation of the in vitro transcribed gRNAs into stable Cas9-expressing LCL was a more efficient gene-editing technique as compared to plasmid-mediated transfection, and that the positive rates could reach up to 35.9%. The predominance of indel sizes relative to the predicted deletion length was clustered between 10 and 0 bp. The results of whole-genome sequencing also demonstrated the existence of SEA-type deletion of α-thalassemia. CONCLUSIONS: Gene-editing based on Cas9-expressing LCL by electroporation of sgRNA was a more efficient approach to introduce mutations for generating quality control materials for genetic testing. The edited lymphoblastoid cell lines were feasible to serve as quality control materials in genetic testing.

8.
Macromol Rapid Commun ; 41(8): e1900543, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32078213

RESUMO

As one of the most promising intelligent materials, polymeric hydrogel actuators could produce reversible shape change upon external stimuli. Although complex shape deformation from 2D to 3D have been achieved, the realization of actuating behavior from 3D to 3D is still a significant challenge. Herein, an effective strategy to develop a novel bilayer hollow spherical hydrogel actuator is proposed. Through immersing a Ca2+ incorporated gelatin core into alginate solution, an ionic-strength-responsive alginate layer will be formed along the gelatin core via alginate-Ca2+ crosslinks, and then another thermo-responsive alginate-poly(2-(dimethylamino)ethyl methacrylate)(Alg-PDMAEMA) layer is introduced to achieve a bilayer hydrogel with ionic strength and temperature dual responsiveness. A hollow hydrogel capsule could be obtained if a spherical gelatin core is applied, and it could produce complex shape deformations from 3D to 3D upon the trigger of ionic strength and temperatures changes. The present work may offer new inspirations for the development of novel intelligent polymeric hydrogel actuators.

9.
Lasers Med Sci ; 2020 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-32065300

RESUMO

In spinal cord injury (SCI), inflammation is a major mediator of damage and loss of function and is regulated primarily by the bone marrow-derived macrophages (BMDMs). Photobiomodulation (PBM) or low-level light stimulation is known to have anti-inflammatory effects and has previously been used in the treatment of SCI, although its precise cellular mechanisms remain unclear. In the present study, the effect of PBM at 810 nm on classically activated BMDMs was evaluated to investigate the mechanisms underlying its anti-inflammatory effects. BMDMs were cultured and irradiated (810 nm, 2 mW/cm2) following stimulation with lipopolysaccharide and interferon-γ. CCK-8 assay, 2',7'-dichlorofluorescein diacetate assay, and ELISA and western blot analysis were performed to measure cell viability, reactive oxygen species production, and inflammatory marker production, respectively. PBM irradiation of classically activated macrophages significantly increased the cell viability and inhibited reactive oxygen species generation. PBM suppressed the expression of a marker of classically activated macrophages, inducible nitric oxide synthase; decreased the mRNA expression and secretion of pro-inflammatory cytokines, tumor necrosis factor alpha, and interleukin-1 beta; and increased the secretion of monocyte chemotactic protein 1. Exposure to PBM likewise significantly reduced the expression and phosphorylation of NF-κB p65 in classically activated BMDMs. Taken together, these results suggest that PBM can successfully modulate inflammation and polarization in classically activated BMDMs. The present study provides a theoretical basis to support wider clinical application of PBM in the treatment of SCI.

10.
J Neuroinflammation ; 17(1): 2, 2020 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-31900229

RESUMO

BACKGROUND: Diabetes mellitus (DM) and chronic cerebral hypoperfusion(CCH)are both risk factors for cognitive impairment. However, whether DM and CCH can synergistically promote cognitive impairment and the related pathological mechanisms remain unknown. METHODS: To investigate the effect of DM and CCH on cognitive function, rats fed with high-fat diet (HFD) and injected with low-dose streptozotocin (STZ) followed by bilateral common carotid artery occlusion (BCCAO) were induced to mimic DM and CCH in vivo and mouse BV2 microglial cells were exposed to hypoxia and/or high glucose to mimic CCH complicated with DM pathologies in vitro. To further explore the underlying mechanism, TREM-2-specific small interfering RNA and TREM-2 overexpression lentivirus were used to knock out and overexpress TREM-2, respectively. RESULTS: Cognitive deficits, neuronal cell death, neuroinflammation with microglial activation, and TREM-2-MAPK signaling were enhanced when DM was superimposed on CCH both in vivo and in vitro. Manipulating TREM-2 expression levels markedly regulated the p38 MAPK signaling and the inflammatory response in vitro. TREM-2 knockout intensified while TREM-2 overexpression suppressed the p38 MAPK signaling and subsequent pro-inflammatory mediator production under high glucose and hypoxia condition. CONCLUSIONS: These results suggest that TREM-2 negatively regulates p38 MAPK-mediated inflammatory response when DM was synergistically superimposed on CCH and highlight the importance of TREM-2 as a potential target of immune regulation in DM and CCH.

11.
J Sep Sci ; 43(6): 1173-1182, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31919992

RESUMO

Curcumin widely exists in food, and rapid selective and accurate detection of curcumin have great significance in chemical industry. In this experiment, a new magnetic biocompatibility molecularly imprinted polymer was prepared with nontoxic and biocompatible Zein to adsorb curcumin selectively. The polymer has high biocompatibility, good adsorption capacity, and specific adsorption for curcumin. Combined with portable electrochemical workstations, the polymer can be used to detect curcumin rapidly and cost-effectively. Using curcumin as a template and Zein as the crosslinking agent, the polymers were synthesized on the surface of Fe3 O4 particles for solid phase extraction. The experimental results showed that the polymer reached large adsorption capacity (32.12 mg/g) with fast kinetics (20 min). The adsorption characteristic of the polymer followed the Langmuir isotherm and pseudo-second-order kinetic models. Hexacyanoferrate was used as electrochemical probe to generate signals, and the linear range was 5-200 µg/mL for measuring curcumin. The experimental analysis showed that the polymer was an ideal material for selective accumulation of curcumin from complex samples. This approach has been successfully applied to the determination of curcumin in food samples with electrochemical detection, indicating that this is a feasible and practical technique.

12.
J Laparoendosc Adv Surg Tech A ; 30(4): 389-394, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31928499

RESUMO

Background: The therapeutic value of bursectomy remains controversial for patients with gastric cancer. Therefore, the purpose of our study was to explore the safety and survival benefits of bursectomy. Materials and Methods: A total of 943 patients with gastric adenocarcinoma were included in our study, and all patients were operated on by high-quality gastrointestinal surgeons. The factors associated with overall survival (OS) were determined using the Kaplan-Meier method. In addition, patients in the bursectomy group and nonbursectomy group were matched with 1:1 propensity score matching for sex, age, tumor location, type of operation, tumor size, degree of differentiation, and pathological stage to reduce the possibility of choice bias. Results: Among the 943 eligible patients, 188 (19.9%) underwent bursectomy and 755 (80.1%) did not. In all patients, the number of retrieved lymph nodes (P = .0596), blood loss volume (P = .0896), operation time (P = .0747), number of postoperative complications (P = .626), and OS in the bursectomy group were similar to those in the nonbursectomy group. After a stratified analysis of TNM grade and T stage, it was found that bursectomy could lead to survival benefits for patients with stage T4 disease (P = .0398). Conclusions: Bursectomy does not increase the amount of blood loss, operation time, or incidence of postoperative complications. This procedure is an extended and safe surgical method for gastric adenocarcinoma. Bursectomy does not improve the survival of all patients, but for patients with stage T4 disease, bursectomy can provide survival benefits.

13.
Artigo em Inglês | MEDLINE | ID: mdl-31995475

RESUMO

We present an algorithm to directly solve numerous image restoration problems (e.g., image deblurring, image dehazing, and image deraining). These problems are ill-posed, and the common assumptions for existing methods are usually based on heuristic image priors. In this paper, we show that these problems can be solved by generative models with adversarial learning. However, a straightforward formulation based on a straightforward generative adversarial network (GAN) does not perform well in these tasks, and some structures of the estimated images are usually not preserved well. Motivated by an interesting observation that the estimated results should be consistent with the observed inputs under the physics models, we propose an algorithm that guides the estimation process of a specific task within the GAN framework. The proposed model is trained in an end-to-end fashion and can be applied to a variety of image restoration and low-level vision problems. Extensive experiments demonstrate that the proposed method performs favorably against the state-of-the-art algorithms.

14.
Clin Chim Acta ; 500: 10-19, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31604064

RESUMO

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related deaths worldwide. HCC patients are commonly diagnosed at an advanced stage, for which highly effective therapies are limited. Hence, there is a growing need to discover promising biomarkers for HCC diagnosis, and in this context, microRNAs (miRNAs) hold great promise. MiRNAs function as gene expression regulators by directly binding messenger RNAs (mRNAs) and subsequently causing suppression of mRNA translation or degradation of target mRNAs. Two major types of noncoding RNAs act as competing endogenous sponges: circular RNAs and long non-coding RNAs.They can competitively bind to miRNA through miRNA response elements (MREs), thereby reducing the number of miRNAs binding mRNAs and regulating the expression of downstream target genes of miRNAs at the posttranscriptional level. The relationship between single miRNA sponge and HCC has been explored. However, comprehensive reviews on the sponge's function in HCC are lacking. In this review, we describe the methods to find endogenous sponges and construct exogenous sponges, and briefly compare endogenous and exogenous sponges. We also summarize the current progress on the functional role of miRNA sponges in HCC pathogenesis and present their potential value as diagnostic biomarkers and therapeutic targets. In-depth investigations on the function and mechanism of miRNA sponges in HCC will enrich our knowledge of HCC pathogenesis and contribute to the development of effective diagnostic biomarkers and therapeutic targets for HCC.

15.
Bioorg Chem ; 94: 103248, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31548092

RESUMO

Fms-like tyrosine kinase 3 (FLT3) has been considered as a potential drug target for the treatment of acute myeloid leukemia (AML), because of its high and aberrant expression in AML patients, especially the patients with FLT3-ITD mutation. Initiating from a hit compound (IC50: 500 nM against FLT3-ITD), a series of compounds were designed and synthesized based on benzo[d]oxazole-2-amine scaffold to discover new potent FLT3-ITD inhibitors. During the medicinal chemistry works, flexible molecular docking was used to provide design rationale and study the binding modes of the target compounds. Through the mixed SAR exploration based on the enzymatic and cellular activities, compound T24 was identified with potent FLT3-ITD inhibitory (IC50: 0.41 nM) and anti-proliferative (IC50: 0.037 µM against MV4-11 cells) activities. And the binding mode of T24 with "DFG-in" FLT3 was simulated by a 20-ns molecular dynamics run, providing some insights into further medicinal chemistry efforts toward novel FLT3 inhibitors in AML therapy.

16.
Cell Mol Neurobiol ; 40(1): 141-152, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31446561

RESUMO

Spinal cord injury (SCI) stimulates reactive astrogliosis and the infiltration of macrophages, which interact with each other at the injured area. We previously found Photobiomodulation (PBM) significantly decreases the number of M1 macrophages at the injured area of SCI. But the exact nature of the astrocyte response following PBM and relationship with the macrophage have not been explored in detail. In this study, a BALB/c mice model with standardized bilateral spinal cord compression and a macrophage-astrocyte co-culture model were applied to study effects of PBM on astrocytes. Results showed that PBM inhibit the expression of the astrocyte markers glial fibrillary acidic protein (GFAP) and the secretion of chondroitin sulfate proteoglycans (CSPG) in the para-epicenter area, decrease the number of M1 macrophage in vivo. The in vitro experiments indicated M1 macrophages promote the cell viability of astrocytes and the expression of CSPG. However, PBM significantly inhibited the expression of GFAP, decreased activation of astrocyte, and downregulated the expression of CSPG by regulating M1 macrophages. These results demonstrate that PBM may regulate the interaction between macrophages and astrocytes after spinal cord injury, which inhibited the formation of glial scar.

17.
J Cell Mol Med ; 24(1): 476-487, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31667932

RESUMO

Macrophages play key roles in the secondary injury stage of spinal cord injury (SCI). M1 macrophages occupy the lesion area and secrete high levels of inflammatory factors that hinder lesion repair, and M2 macrophages can secrete neurotrophic factors and promote axonal regeneration. The regulation of macrophage secretion after SCI is critical for injury repair. Low-level laser therapy (810-nm) (LLLT) can boost functional rehabilitation in rats after SCI; however, the mechanisms remain unclear. To explore this issue, we established an in vitro model of low-level laser irradiation of M1 macrophages, and the effects of LLLT on M1 macrophage polarization and neurotrophic factor secretion and the related mechanisms were investigated. The results showed that LLLT irradiation decreased the expression of M1 macrophage-specific markers, and increased the expression of M2 macrophage-specific markers. Through forward and reverse experiments, we verified that LLLT can promote the secretion of various neurotrophic factors by activating the PKA-CREB pathway in macrophages and finally promote the regeneration of axons. Accordingly, LLLT may be an effective therapeutic approach for SCI with clinical application prospects.

18.
Environ Sci Pollut Res Int ; 27(2): 1373-1385, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31745810

RESUMO

Although Chinese government has implemented a series of laws, regulations, and policies to deal with air pollutants, air pollution is still one of the biggest concerns in China. Most of the cities in China suffered from extremely high air pollution levels and cannot meet the national air quality standards. In this study, we attempt to measure individuals' average marginal willingness to pay (MWTP) in Beijing with the hedonic price model. We combine an extensive housing transaction dataset with emission data of six air pollutants from 2013 to 2016 in Beijing, China. When estimating the hedonic price function, we apply both ordinary least squares (OLS) and panel model with various fixed effects to better control for unobservables. The empirical results reveal that the concentrations of CO, NO2, PM2.5, and PM10 are significantly negatively correlated with housing prices. However, we found an insignificant relationship with the concentration of SO2 and the concentration of O3 appears to positively increase the housing values. Policy implications based on these results were also discussed.

19.
Chemosphere ; 240: 124878, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31563719

RESUMO

Dihydroxylated polybrominated diphenyl ethers (diOH-PBDEs) can be natural products of marine organisms or the metabolites of PBDEs. The optimal determination method and concentration of diOH-PBDEs in seafood are unknown due to a lack of commercially available standards. In the present study, diOH-PBDEs were synthesized, and an efficient measurement method for OH-PBDEs and diOH-PBDEs in sea fish muscle samples, including extraction, clean-up and gas chromatography-tandem mass spectrometry (GC-MS/MS) analysis, was established. Pressurized liquid extraction (PLE) followed by partitioning with a KOH solution and florisil cartridge clean-up proved to be a reliable and robust method for detecting all OH-PBDEs/diOH-PBDEs. GC-MS/MS with an electron ionization (EI) source analysis was a sensitive analytical instrument for OH-PBDEs/diOH-PBDEs. The recovery using this method ranged from 19% to 101%, 28%-88% and 42%-90% for 10 ng, 20 ng and 40 ng spiking levels, respectively. The equipment detection limits (EDLs) were in the range of 0.31-2.78 pg/µL, and the limits of detection (LOD) for the method were in the range of 5.07-38.74 pg/g wet weight. Concentrations of diOH-PBDEs in the marine fish muscle samples were in the range of 32.43-1528.63 pg/g wet weight. Similar compositions of OH-PBDEs/diOH-PBDEs were found within the same family of marine fish.


Assuntos
Peixes/metabolismo , Cromatografia Gasosa-Espectrometria de Massas/métodos , Éteres Difenil Halogenados/análise , Espectrometria de Massas em Tandem/métodos , Animais , Limite de Detecção
20.
Bioorg Med Chem Lett ; 30(4): 126901, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31882299

RESUMO

Early studies demonstrated that over expression of indoleamine 2,3-dioxygenase (IDO1) in tumor microenvironment results in tumor immune escape. Herein, in order to simplify the structure of two kinds of IDO1 inhibitors from marine alkaloid, Exiguamine A and Tsitsikammamines, we designed, synthesized a series of 1H-indole-4,7-dione derivatives and evaluated their inhibitory activity in IDO1 enzyme and in IFN-γ stimulated Hela cells in vitro. The structure-activity relationship demonstrated that 5-(pyridin-3-yl)-1H-indole-4,7-dione is a promising scaffold for IDO1 inhibitors and most compounds with this core showed moderate inhibition potency at micromole level. Our further enzyme kinetics experiments reveal that these new developed compounds might act as reversible competitive inhibitors of IDO1.

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