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1.
Toxicol In Vitro ; 62: 104698, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31669364

RESUMO

Both PM2.5 and respiratory viruses are part of the atmospheric constituents. Respiratory viruses are often associated with PM2.5 exposure, but the mechanism of toxicity remains to be explored. The vitro models that adequately reproduce healthy cells or diseased cells exposing to PM2.5 and infecting VSV can provide a useful tool for studying innate immune mechanisms and investigating new therapeutic focus. In the environment of PM2.5, an infection model in which VSV infected A549 cells was established, that mimics the state in which the antiviral innate immune pathways are activated after the respiratory system is infected with RNA viruses. Subsequently, the model was exposed to PM2.5 for 24 h. PM2.5 could be ingested by A549 cells and synergize with VSV to inhibit cell viability and promote apoptosis. The expression of VSV-G were more abundant after VSV-infected A549 cells were exposed to PM2.5. Furthermore, PM2.5 inhibits VSV-induced IFN-ß expression in A549 cells. ISG15, CCL-5, and CXCL-10 had the same expression tendency with IFN-ß mRNA, consistently. Interestingly, when MG132 was applied, the expression of p-IRF-3 and IFN-ß proteins reduced by PM2.5 were refreshed. Conversely, the expression of VSV-G proteins were decreased. PM2.5 could degrade p-IRF-3 proteins by ubiquitination pathway to inhibit VSV-induced IFN-ß expression in A549 cells. Therefore, replication of the VSV viruses was promoted.

2.
J Hazard Mater ; 383: 121211, 2020 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-31546219

RESUMO

In order to achieve strong specific recognition and remarkable synergy between adsorption and photocatalysis, carbon nanosheets supported TiO2 (CT) was designed and embellished by molecular imprinting technology with ciprofloxacin (CIP) as template. The molecular imprinted CT (CT-MI) product exhibited remarkable synergy of adsorption-photocatalysis and high selectivity in both aspects, benefitted from specific recognition of imprinted layer, strong carbon adsorption and electroconductivity, and enhanced photocatalysis. Compared to the competitive pollutant, sulfamethoxazole (SMZ) in this study, selectivity coefficient was 7.2 for adsorption and 3.2 for photocatalysis, respectively. This is superior to most of the imprinted photocatalysts reported in the literature. In addition, effect of mass ratio between TiO2 matrix to imprinted polymers, as well as water quality and composition, to the performance of final product was studied and favorable conditions were proposed. Electron transfer mode, selective recognition mode, and antibiotics degradation mechanism and pathways were also illustrated based on trapping experiments and HPLC-MS technology etc. This study confirmed that alliance between molecular imprinting, carbon nanosheets and well dispersed photocatalyst possessed broad prospect of applications in specific recognition and selective degradation of a highly toxic pollutant in a variety of mixed systems.

3.
Nat Cell Biol ; 21(11): 1346-1356, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31685995

RESUMO

In the past two decades, emerging studies have suggested that DExD/H box helicases belonging to helicase superfamily 2 (SF2) play essential roles in antiviral innate immunity. However, the antiviral functions of helicase SF1, which shares a conserved helicase core with SF2, are little understood. Here we demonstrate that zinc finger NFX1-type containing 1 (ZNFX1), a helicase SF1, is an interferon (IFN)-stimulated, mitochondrial-localised dsRNA sensor that specifically restricts the replication of RNA viruses. Upon virus infection, ZNFX1 immediately recognizes viral RNA through its Armadillo-type fold and P-loop domain and then interacts with mitochondrial antiviral signalling protein to initiate the type I IFN response without depending on retinoic acid-inducible gene I-like receptors (RLRs). In short, as is the case with interferon-stimulated genes (ISGs) alone, ZNFX1 can induce IFN and ISG expression at an early stage of RNA virus infection to form a positively regulated loop of the well-known RLR signalling. This provides another layer of understanding of the complexity of antiviral immunity.

4.
Biosci Trends ; 13(5): 423-429, 2019 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-31666440

RESUMO

In-stent restenosis is highly related to the deposition of inflammatory extracellular matrix and the migration of endothelial and vascular smooth muscle cells. The miR-17/TIMP-1/interleukin pathway regulates vascular matrix remodeling and plays an important role in the inflammatory reaction. This study identified miR-17 and its related biomarkers in serum that potentially indicated susceptibility to in-stent restenosis (ISR) after coronary artery stenting. Subjects were 42 patients with single de novo coronary artery lesions who underwent regular coronary angiography one year after percutaneous coronary intervention. The clinical baseline information was recorded. Serum levels of biomarkers (including miR-17, TIMP-1, IL-6, IL-8, IL-2R, TNF-alpha, IL-10, and IL-1beta) were measured with real-time PCR or ELISA. Intergroup comparisons were used to compare patients with or without ISR. Compared to levels in the non-restenosis group, the serum miR-17 level was significantly higher (3.13 ± 0.22 vs. 1.06 ± 0.04, p < 0.01) and the serum TIMP-1 and IL-6 levels were significantly lower in the ISR group (TIMP-1: 0.33 ± 0.04 vs. 1.00 ± 0.05, p < 0.01; IL-6: 1.64 ± 0.18 vs. 3.52 ± 0.11, p < 0.01). Moreover, the levels of TIMP-1 and IL-6 decreased as the level of miR-17 increased. Spearman's correlation analysis indicated that the miR-17 level was inversely correlated with TIMP-1 and IL-6 levels. Findings suggest that an elevated level of miR-17 and decreased levels of TIMP-1 and IL-6 may be associated with the risk of ISR, which is in accordance with vascular matrix remodeling and an inflammatory reaction during the pathologic process of ISR. This study highlighted the potential for miR-17, TIMP-1, and IL-6 to serve as biomarkers for ISR.

5.
J Cell Mol Med ; 2019 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-31725199

RESUMO

Bone homeostasis is delicately orchestrated by osteoblasts and osteoclasts. Various pathological bone loss situations result from the overactivated osteoclastogenesis. Receptor activator of nuclear factor κB ligand (RANKL)-activated NF-κB and MAPK pathways is vital for osteoclastogenesis. Here, we for the first time explored the effects of l-tetrahydropalmatine (l-THP), an active alkaloid derived from corydalis, on the formation and function of osteoclasts in vitro and in vivo. In RAW264.7 cells and bone marrow monocytes cells (BMMCs), l-THP inhibited osteoclastic differentiation at the early stage, down-regulated transcription level of osteoclastogenesis-related genes and impaired osteoclasts functions. Mechanically, Western blot showed that l-THP inhibited the phosphorylation of P50, P65, IκB, ERK, JNK and P38, and the electrophoretic mobility shift assay (EMSA) revealed that DNA binding activity of NF-κB was suppressed, ultimately inhibiting the expression of nuclear factor of activated T cells (NFATc1). Besides, Co-immunoprecipitation indicated that l-THP blocked the interactions of RANK and TNF receptor associated factor 6 (TRAF6) at an upstream site. In vivo, l-THP significantly inhibited ovariectomy-induced bone loss and osteoclastogenesis in mice. Collectively, our study demonstrated that l-THP suppressed osteoclastogenesis by blocking RANK-TRAF6 interactions and inhibiting NF-κB and MAPK pathways. l-THP is a promising agent for treating osteoclastogenesis-related diseases such as post-menopausal osteoporosis.

6.
Biomaterials ; : 119614, 2019 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-31753475

RESUMO

The severe mortality and morbidity of myocardial infarction requests appropriate and accurate detection. Considering pathological profile of the acidic myocardial infarction microenvironments, herein, the low pH-sensitive albumin nanocomposites with MnO2 motifs (MnO2@BSA) have been engineered for T1-weighted MR imaging of myocardial infarction, while using non-pH-responsive Gd2O3@BSA nanocomposites as control. The nanocomposites were 20-30 nm in diameter with spheroid morphology. Besides, the MnO2@BSA have exhibited pH-triggered releasing of Mn2+, demonstrating approximately 38-fold and 55-fold increased molecular relaxivity at acute myocardial infarction-mimicking pH 6.5 (13.08 mM-1s-1) and macrophage intracellular pH 5.0 (18.76 mM-1s-1) compared to the extremely low relaxivity (0.34 mM-1s-1) at normal physiological conditions (pH 7.4). However, the Gd2O3@BSA with molecular relaxivity approximately 10 mM-1s-1 were without pH-sensitive properties. Furthermore, the MnO2@BSA have demonstrated high accumulation in the acute myocardial infarction regions and fast metabolism from the body after systemic injection, accounting high contrast enhancement for accurate MR imaging of acute myocardial infarction in rabbit models, demonstrating better diagnostic performance over the controls.

7.
Asian Pac J Cancer Prev ; 20(11): 3251-3258, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31759346

RESUMO

BACKGROUND: This research studied the relationship between maternal exposure to polychlorinated biphenyls and neonatal birth weight through systematic review and meta-analysis of existing literature. METHODS: We searched for all the studies published in MEDLINE / PUBMEDN / EMBASE (Medical Abstract Database) by June 2018, and seven studies had been selected. RESULTS: The results showed that there was significant correlation between birth weight reduction and PCBS exposure throughout pregnancy (ß=-0.586g, 95%CI:-0.629,-0.543). There was a negative correlation between birth weight and PCBs exposure and umbilical cord serum (ß=-0.833g) and maternal serum (ß= -0.504g).Subgroup analyses showed significantly different effects of PCBs exposure on birth weight in different regions, stages of pregnancy and study designs. It was thought the heterogeneity was mainly caused by geographical regions, stages of pregnancy, and the assessment methods. CONCLUSION: The meta analysis revealed a negative correlation between PCBs exposure and birth weight but there was significant difference in the correlation between birth weight loss.

8.
Artigo em Inglês | MEDLINE | ID: mdl-31713409

RESUMO

Photocatalytic water splitting over layered nanosheet (NS) catalysts has caught a lot of attention for renewable hydrogen fuel production. However, the weak van der Waals interlayer interactions make it a great challenge to realize an effective dissociation of photogenerated excitons and efficient charge transfer across the interior of layered catalysts during the photocatalysis process. Here, we propose an intercalation strategy of high-valence RuIV atoms to render two-dimensional GaS NS photocatalysts with rapid electron-hole dissociation and long photocarrier lifetime in visible-light-driven water splitting. Experimental and theoretical results unravel that the intercalated single-site Ru, confined in interlayer of GaS NSs, with a hexagonal structural configuration of "Ru1-S6", can serve as an electron-trapped high-speed channel toward simultaneously accelerating electron-hole pairs dissociation and promoting photoelectron transportation through the van der Waals interlayer. Consequently, the as-developed Ru-intercalated GaS NSs can give a notable H2 production rate of 340 µmol g-1 h-1 under visible-light irradiation and an apparent yield of 7% at 420 nm, 38 times that of pure GaS NSs. This study opens up a feasible way for a new design of highly active layered photocatalysts toward high-efficiency solar energy conversion.

9.
Sci Total Environ ; 702: 135056, 2019 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-31731128

RESUMO

Limited researches are available on seasonal variation of inhalation exposure of polycyclic aromatic hydrocarbons (PAHs) and its cancer risk assessment in China. We recruited 20 fresh postgraduates and measured outdoor and indoor (dormitories, offices and laboratories) daily PM2.5 concentrations in four seasons (seven consecutive days in every season) during 2014 -2015, calculated daily potential doses of personal exposure to total Benzo[a]pyrene equivalent concentration (BaPeq) in the microenvironments based on the total BaPeq and the time-activity patterns, and estimated incremental lifetime cancer risk (ILCR) using Monte Carlo method. Daily average concentrations of PM2.5-bound ∑PAHs on the campus ranked from high to low were winter, autumn, spring, summer in the dormitories and offices. Daily average concentration of PM2.5-bound ∑PAHs were higher in indoor environments than outdoor in the same season, except for that of PM2.5-bound ∑PAHs in laboratories in the winter. Median values of ILCR in both sexes from high to low were winter (men vs. women: 5.35e-9 vs. 4.96e-9), spring (3.71e-9 vs. 4.00e-9), autumn (2.92e-9 vs. 3.02e-9), summer (1.71e-9 vs. 1.87e-9). Indoor and outdoor PM2.5-bound PAHs concentrations showed seasonal and spatial variations. The ILCR value for PM2.5-bound PAHs was higher in women than in men.

10.
Artigo em Inglês | MEDLINE | ID: mdl-31751195

RESUMO

Two yellow-pigmented, Gram-stain-negative and rod-shaped bacterial strains, designated as RY24T and ZYY160, were isolated from rice. Results of phylogenetic analysis based on 16S rRNA gene sequences showed that strains RY24T and ZYY160 belonged to the genus Pseudomonas, and the 16S rRNA gene sequence similarity was 100 % The DNA homology between the two strains was 99.7 %. The 16S rRNA and rpoD gene sequences of the two strains showed highest similarity values to Pseudomonas oryzihabitans CGMCC 1.3392T and Pseudomonas psychrotolerans DSM 15758T (sharing 99.31 and 94.34 %, respectively). The major fatty acids of two strains were identified as summed feature 8 (C18:1ω7c and/or C18:1ω6c), C16;0 and summed feature 3 (C16:1ω7c and/or C16:1ω6c), and the major respiratory quinone was identified as ubiquinone Q-9, which are typical chemotaxonomic features of members of the genus Pseudomonas. The genomic DNA G+C contents of strains RY24T and ZYY160 were determined to be 64.25 and 64.21 mol%, respectively. The DNA-DNA relatedness and average nucleotide identity values between the two strains and their closely related type strains were below 36 and 90 %, which supported that RY24T and ZYY160 represent a novel species in the genus Pseudomonas. Phylogenetic and chemotaxonomic evidence, together with phenotypic characteristics, showed that the two isolates constitute a novel species of the genus Pseudomonas. The type strain is RY24T (JCM 33201T=ACCC 61555T), for which the name Pseudomonas rhizoryzae sp. nov. is proposed.

11.
Am J Chin Med ; 47(7): 1541-1569, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31752524

RESUMO

Corilagin is a polyphenol that can be extracted from many medicinal plants and shows multiple pharmacological effects. We aimed to investigate the role of corilagin on miR-21-regulated hepatic fibrosis, especially miR-21-regulated TGF-ß1/Smad signaling pathway, in hepatic stellate LX2 cell line and Sprague-Dawley rats. The mRNA or protein levels of miR-21, Smad7, connective tissue growth factor (CTGF), α-smooth muscle actin (α-SMA), tissue inhibitor of metalloproteinase-1 (TIMP-1), matrix metalloproteinase-9 (MMP-9), collagen type I alpha 1 (COL1A1), Smad2, Smad3, Smad2/3, p-Smad2, p-Smad3, p-Smad2/3, and transforming growth factor-ß1 (TGF-ß1) in LX2 cells and liver tissues were determined. Furthermore, gain-of and loss-of function of miR-21 in miR-21-regulated TGF-ß1/Smad signaling pathway were analyzed in LX2 cells. Liver tissues and serum were collected for pathological analysis, immunohistochemical staining, and enzyme-linked immunosorbent assay (ELISA). Corilagin treatment reduced mRNA or protein levels of miR-21, CTGF, α-SMA, TIMP-1, TGF-ß1, COL1A1, p-Smad2, p-Smad3, and p-Smad2/3 both in vitro and in vivo. While corilagin increased mRNA and protein levels of Smad7 and MMP-9. After gain-of and loss-of function of miR-21, the downstream effectors of miR-21-regulated TGF-ß1/Smad signaling pathway in LX2 cells changed accordingly, and the changes were inhibited by corilagin. Simultaneously, administration of corilagin not only ameliorated pathological manifestation of liver fibrosis but also reduced levels of α-SMA and COL1A1 in liver tissues and TGF-ß1, ALT levels in serum. Corilagin is able to potentially prevent liver fibrosis by blocking the miR-21-regulated TGF-ß1/Smad signaling pathway in LX2 cells and CCl4-induced liver fibrosis rats, which may provide a novel therapeutic strategy for liver fibrosis.

12.
13.
Eur J Clin Pharmacol ; 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31677118

RESUMO

PURPOSE: Our aim was to evaluate the influence of genetic polymorphisms involved in the metabolism and transportation of deferasirox on deferasirox pharmacokinetics in the Chinese population. METHODS: Thirty-eight healthy Chinese subjects were administered with a single dose of 20 mg kg-1 deferasirox. Allelic discriminations for eight single-nucleotide polymorphisms (SNPs) in UDP-glucuronosyltransferase 1A1, 1A3 (UGT1A1, UGT1A3), multidrug resistance protein 2 (MRP2, ABCC2), and breast cancer resistance protein (BCRP, ABCG2) were performed. The concentrations of deferasirox in the plasma were determined by UPLC-MS/MS. RESULTS: Subjects carrying ABCC2 c.-24 T allele had a 65% higher clearance (CL/F) and 42% lower area under the concentration-time curve from 0 to 72 h (AUC0-72h) as compared with non-carriers (P = 0.008, P = 0.011, respectively). ABCC2 c.-24 T was also associated with 59% shorter half-life (T1/2) and 17% shorter mean residence time (MRT) (P = 0.030, P = 0.014, respectively). ABCC2 1249A was associated with a marginal increase in deferasirox Cmax (P = 0.07). Genetic polymorphisms of UGT1A1, UGT1A3, and ABCG2 did not significantly influence the pharmacokinetics of deferasirox. Subjects with UGT1A1 211GG-(-1352)CC-(-3156)GG haplotype had higher AUC0-72h than others. Since only two subjects were recruited in the GG-CC-GG group, further confirmative studies were warranted. CONCLUSIONS: ABCC2 c.-24 C>T was associated with the pharmacokinetic variability of deferasirox in Chinese subjects. This study revealed an important role of MRP2 in the pharmacokinetics of deferasirox and drew attention to drug combination with MRP2 inhibitors like cyclosporine and methotrexate in deferasirox therapy.

14.
Int J Med Robot ; : e2044, 2019 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-31674135

RESUMO

BACKGROUND: Robot-assisted puncture has gradually attracted more attention and practical clinical application. The lesion positioning and the needle positioning are the basis to ensure the accuracy of puncture and the key techniques in insertion operation. METHODS: A lesion positioning method is established which is realized only by the robot-CT system without using external positioning system, and an omnidirectional needle positioning method is also developed and realized by using VRCM, in order to make the puncture needle always keep pointing to the lesion point. A CT-guided surgical robotic system used for minimally invasive percutaneous lung is designed and the physical prototype is manufactured, to perform in-vitro experiments, thereby to validate the effectiveness of the lesion positioning method and the feasibility of omnidirectional needle positioning method. RESULTS: The accuracy of established lesion positioning method based on three non-collinear markers is within 3 mm, which is similar to that of the least squares method based on the five non-coplanar markers, but the positioning efficiency can be improved by about 40%, and the non-collinearity of markers is easier to be satisfied than non-coplanarity in practical applications. The average calculation error of the established positioning method is 0.997 mm. Moreover, the omnidirectional positioning of the puncture needle under the designed surgical robot is feasible. CONCLUSIONS: The designed surgical robot has good control accuracy and it can satisfy the requirements for use. The established lesion positioning method can provide a good precision basis for robot-assisted puncture surgery. The suitable insertion point and insertion posture can be determined by the developed omnidirectional needle positioning method. This work can provide theoretical reference for further study of path planning or autonomous positioning.

15.
Neuron ; 2019 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-31761710

RESUMO

Transmembrane channel-like (TMC) 1 and 2 are required for the mechanotransduction of mouse inner ear hair cells and localize to the site of mechanotransduction in mouse hair cell stereocilia. However, it remains unclear whether TMC1 and TMC2 are indeed ion channels and whether they can sense mechanical force directly. Here we express TMC1 from the green sea turtle (CmTMC1) and TMC2 from the budgerigar (MuTMC2) in insect cells, purify and reconstitute the proteins, and show that liposome-reconstituted CmTMC1 and MuTMC2 proteins possess ion channel activity. Furthermore, by applying pressure to proteoliposomes, we demonstrate that both CmTMC1 and MuTMC2 proteins can indeed respond to mechanical stimuli. In addition, CmTMC1 mutants corresponding to human hearing loss mutants exhibit reduced or no ion channel activity. Taken together, our results show that the CmTMC1 and MuTMC2 proteins are pore-forming subunits of mechanosensitive ion channels, supporting TMC1 and TMC2 as hair cell transduction channels.

16.
Br J Neurosurg ; : 1-6, 2019 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-31747787

RESUMO

Purpose: To evaluate surgical outcomes and cognitive improvements after posterior quadrantic disconnection (PQD) in children who had medically intractable epilepsy and to compare the various characteristics between the acquired group and the developmental group.Method: Between 2015 and 2017, we retrospectively enrolled all pediatric patients who underwent PQD. We used image post-processing techniques for preoperative evaluation. Seizure outcomes and postoperative cognitive improvements were analysed. The patients were divided into the acquired group and the developmental group depending on the pathology; we then compared groups regarding age at onset, surgery, history, and seizure and cognitive outcomes.Results: A total of 12 pediatric patients were enrolled, including 7 acquired patients and 5 developmental patients. After a median 28.9-month follow-up, 11 (91.7%) of 12 patients were seizure free. The image post-processing facilitated a better visualization on preoperative evaluation and helped with detection of the epileptogenic zone. There were significant linear relationships between improvements in IQ and operative age (R2=0.527, p = 0.007) and IQ and epileptic history (R2=0.696, p = 0.001). The median age at seizure onset was 4.86 ± 2.12 years in the acquired group and 2.40 ± 1.14 years in the developmental group (t = 2.344, p = 0.028). Epileptic histories, seizure outcomes and cognitive outcomes were not significantly different between groups.Conclusion: Posterior quadrantic disconnection is an effective epilepsy surgery in selected patients. The use of image post-processing is important for preoperative evaluation. The age at seizure onset and surgery in malformation of cortical development (MCD) patients was earlier; however, the seizure outcome was no better than in acquired pathology patients. Early surgery did not change seizure outcomes but improved cognition.

17.
Epilepsia ; 2019 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-31769021

RESUMO

OBJECTIVE: Temporal lobe epilepsy is a common form of epilepsy that might be amenable to surgery. However, magnetic resonance imaging (MRI)-negative hippocampal sclerosis (HS) can hamper early diagnosis and surgical intervention for patients in clinical practice, resulting in disease progression. Our aim was to automatically detect and evaluate the structural alterations of HS. METHODS: Eighty patients with pharmacoresistant epilepsy and histologically proven HS and 80 healthy controls were included in the study. Two automated classifiers relying on clinically empirical and radiomics features were developed to detect HS. Cross-validation was implemented on all participants, and specificity was assessed in the 80 controls. The performance, robustness, and clinical utility of the model were also evaluated. Structural analysis was performed to investigate the morphological abnormalities of HS. RESULTS: The computational model based on clinical empirical features showed excellent performance, with an area under the curve (AUC) of 0.981 in the primary cohort and 0.993 in the validation cohort. One of the features, gray-white matter boundary blurring in the temporal pole, exhibited the highest weight in model performance. Another model based on radiomics features also showed satisfactory performance, with AUC of 0.997 in the primary cohort and 0.978 in the validation cohort. In particular, the model improved the detection rate of MRI-negative HS to 96.0%. The novel feature of cortical folding complexity of the temporal pole not only played a crucial role in the classifier but also had significant correlation with disease duration. SIGNIFICANCE: Machine learning with quantitative clinical and radiomics features is shown to improve HS detection. HS-related structural alterations were similar in the MRI-positive and MRI-negative HS patient groups, indicating that misdiagnosis originates mainly from empirical interpretation. The cortical folding complexity of the temporal pole is a potentially valuable feature for exploring the nature of HS.

18.
Nanotechnology ; 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31731282

RESUMO

With two different residual surfactants, four different metal nanoparticles (NPs), including two Au NPs and two Ag NPs are synthesized for linking with red-emitting CdZnSeS/ZnS colloidal quantum dots (QDs) to enhance QD emission efficiency. Those metal NPs are first connected with amino polyethylene glycol thiol of different molecular weights to avoid aggregation and make them positively charged. They can attract negatively charged QDs for inducing surface plasmon (SP) coupling such that either QD absorption or emission and hence overall color conversion efficiency can be enhanced. The enhancement of QD emission efficiency is evaluated through the comparison of time-resolved photoluminescence behaviors under different QD linkage conditions. Such results are confirmed by the measurement of the emission quantum efficiency of QD. It is found that by linking QDs onto Ag NPs, the QD emission efficiency is more enhanced, when compared with Au NPs. Also, depending on the synthesis process, the residual surfactant of citrate leads to a relatively larger increment in QD emission efficiency, when compared to the surfactant of cetrimonium chloride. A more enhanced QD emission efficiency is caused by a higher QD linkage capability and a stronger SP coupling effect.

19.
Artigo em Inglês | MEDLINE | ID: mdl-31773527

RESUMO

Despite the benefits of shellfish consumption, the bioaccumulation of heavy metals in shellfish can endanger consumer's health. The consumption of seafood in Shenzhen (a fast-developing metropolis in China) has received more and more attention. Arsenic (As), cadmium (Cd), copper (Cu), mercury (Hg), and lead (Pb) in ten common shellfish species and associated health risks were analyzed for Shenzhen's consumers by evaluating estimated weekly intake (EWI), non-carcinogenic and carcinogenic health risks to children, adolescents, and adults. In this study, 50 shellfish samples were collected in total. The results showed that the levels of inorganic arsenic (iAs) in Babylonia areolata exceeded the maximum permissible limit set by the food safety guidelines (0.5 mg/kg), while other elements were below the limit in the present guidelines (Ministry of Health of the People's Republic of China, GB 2762-2012). EWI values of children, adolescents, and adults were all lower than provisional tolerable weekly intakes (PTWIs) of all shellfish species. The analysis of total target hazard quotients (TTHQ) showed that the ingested B. areolata in children, adolescents, and adults were all at non-carcinogenic risks; the consumption of Argopecten irradians and Chlamys farreri would pose non-carcinogenic risks for children only. In all age groups, the consumption of A. irradians, B. areolata, C. farreri, and Crassostrea ariakensis would lead to lifetime cancer risk due to Cd bioaccumulation, with toxicity of Pb and iAs to be acceptable and negligible.

20.
Opt Lett ; 44(23): 5691-5694, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31774755

RESUMO

Four surface-modified and, hence, positively charged metal nanoparticles (NPs) of different localized surface plasmon (LSP) resonance wavelengths are synthesized for linking with negatively charged, red-emitting colloidal CdZnSeS/ZnS quantum dots (QDs) on the top surface of a blue-emitting InGaN/GaN quantum well (QW) light-emitting diode (LED) through electro-static force. The metal NP-QD linkage leads to a short distance between them for producing their strong surface plasmon (SP) coupling, such that QD absorption and emission can be enhanced. Meanwhile, the small p-GaN thickness in the LED results in strong SP coupling between the LSP resonance of metal NP and the QWs of the LED, leading to enhanced QW emission and, hence, stronger QD excitation. All those factors together result in the increase of the color conversion efficiency of the QD.

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