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1.
J Colloid Interface Sci ; 605: 13-22, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34303922

RESUMO

Using previous models and theories to construct and develop high-efficient microwave absorbers (MAs) should be a strategic and effective ways to optimize the electromagnetic wave attenuation. Herein, the ultralow density and flexible graphene oxide foam (GOF) and reduced graphene oxide foam (RGOF)/MoS2 nanosheets were designed and fabricated by the method of chemical vapor deposition and hydrothermal reaction. The obtained GOF and RGOF/MoS2 samples exhibited very excellent microwave absorption properties while their densities were merely 0.0082 and 0.0084 g•cm-3, respectively. More importantly, benefiting from the excellent synergistic effect between RGOF and MoS2, the designed RGOF/MoS2 well inherited the combined advantages of GOF and MoS2 in terms of strong absorption abilities, broad absorption bandwidth and thin matching thicknesses. The values of minimum reflection loss and effective frequency bandwidth for RGOF/MoS2 sample could reach up to -62.92 dB with the matching thickness of 2.27 mm and 4.48 GHz with the matching thickness of 2.12 mm, which were very desirable for high-performance MAs. Moreover, the obtained results indicated that the microwave absorption properties of RGOF/MoS2 sample could be further optimized by regulating the MoS2 content. Therefore, a new and effective strategy was proposed to develop high efficiency MAs with ultra-lightweight, wide-band, thin thickness and strong absorption capabilities.

2.
Front Med (Lausanne) ; 8: 731412, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34650996

RESUMO

Objective: To compare maternal and neonatal outcomes for women with placenta accreta syndrome (PAS) delivering via a planned or emergent approach. Methods: A systematic search for relevant studies was conducted by screening the PubMed, Scopus, Web of Science, and Google Scholar electronic databases. Included studies should have been retrospective record-based or prospective in design. They must have compared maternal and/or neonatal outcomes for PAS patients delivering via planned and emergency procedures. Strength of association was presented as pooled adjusted relative risk (RR) for categorical outcomes and weighted mean difference (WMD) for continuous outcomes. Statistical analysis was done using STATA version 16.0. Results: Nine articles were included in the meta-analysis. PAS patients undergoing planned deliveries had increased gestational ages, required fewer units of transfused blood, experienced shorter hospital stay durations, and presented reduced risks for maternal ICU admission and severe maternal morbidity. Neonates born to mothers undergoing planned deliveries had increased birth weights and decreased NICU admission risk. Conclusion: These findings indicate a planned approach for delivery is better for maternal and neonatal outcomes compared to urgent/emergency delivery for PAS patients.

3.
Anal Bioanal Chem ; 2021 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-34642782

RESUMO

Excessive use of pesticides in modern agriculture results in large amounts of pesticide residues in agricultural production, greatly threatening human health. Herein, novel two-dimensional leaf-like zeolitic imidazolate framework-L decorated with multi-walled carbon nanotubes (MWCNTs/ZIF-L) was prepared by a facile solvent way and exploited as electrode material for sensitive electrochemical sensing of thiabendazole (TBZ). Two-dimensional ZIF-L presents high surface area, large pore volume, and abundant active sites, which exhibits high enrichment ability towards TBZ molecules, while the MWCNTs interspersed on ZIF-L can prominently enhance the electron transport capability and improve the electrocatalytic activity for TBZ oxidation. Due to the intriguing synergy between the components, the MWCNTs/ZIF-L-based electrochemical sensor reveals a limit of detection (LOD) of 6.0 nmol·L-1, which is lower than that reported in most literatures. Additionally, satisfactory reproducibility and repeatability, long-term stability, and excellent selectivity are acquired. The proposed method was also applied for the detection of TBZ in apple and orange samples with acceptable recoveries.

4.
AJR Am J Roentgenol ; 2021 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-34643106

RESUMO

Background: Use of upper gastrointestinal (UGI) series to diagnose UGI obstruction has raised concern in neonates and infants given increased radiation sensitivity by developing organs. Objectives: To assess the diagnostic performance of saline-aided ultrasound for UGI obstruction in neonates and infants, in comparison with UGI series. Methods: This prospective multicenter study enrolled inpatients at three hospitals who were less than 1 year old and had suspected UGI obstruction between June 2015 and May 2018; patients with malrotation or pyloric stenosis on ultrasound were ineligible. Enrolled patients underwent both saline-aided ultrasound (saline administered by nasogastric tube) and UGI series. Surgical findings or at least one-year clinical follow-up served as reference for presence of UGI obstruction. Patients with UGI obstruction were classified in terms of level (proximal vs distal) and cause. Two radiologists independently interpreted saline-aided US examinations to assess interobserver agreement and then reached consensus. Two separate radiologists assessed upper GI series in consensus. Diagnostic performance for UGI obstruction presence and level was compared between modalities. Causes were assessed on saline-aided ultrasound. Results: A total of 209 neonates were included (median age 5 days; 116 male, 93 female); 124 (59.3%) had UGI obstruction (proximal in 108). Saline-aided ultrasound exhibited strong interobserver agreement for obstruction presence (κ=0.87) and level (κ=0.85). For presence of UGI obstruction, accuracy, sensitivity, and specificity were 94.7%, 98.4%, and 89.4% for saline-aided US, versus 89.5%, 95.2%, and 81.5% for UGI series. For obstruction level, accuracy, sensitivity, and specificity were 91.9%, 97.2%, and 56.3% for saline-aided US, versus 87.1%, 92.6%, and 50.0% for UGI series. Accuracy for presence was significantly higher for saline-aided US (p=.02); otherwise, these metrics were not different between tests (p>.05). For causes of UGI obstruction (annual pancreas, duodenal web, duodenal atresia, and duodenal stenosis), accuracy of saline-aided US ranged from 75.0% to 94.1%. Conclusion: Saline-aided US has high diagnostic performance for presence and level of UGI obstruction in neonates and infants, comparing favorably versus UGI series. Saline-aided US may have additional utility in evaluating causes of obstruction. Clinical Impact: Saline-aided US may serve as an initial screening modality for UGI obstruction in neonates and infants.

5.
Magn Reson Imaging ; 84: 115-123, 2021 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-34619291

RESUMO

OBJECTIVES: Liver vessel density can be evaluated by DDVD (diffusion derived vessel density): DDVD(b0b1) = Sb0/ROIarea0 - Sb1/ROIarea1, where Sb0 and Sb1 refer to the liver signal when b is 0 or 1 s/mm2. Sb1 and ROIarea1 may be replaced by other b-values. With a rat biliary duct ligation (BDL) model, this study assesses the usefulness of liver DDVD computed from a simplified IVIM imaging protocol using b = 25 and b = 50 to replace b = 1 s/mm2, alone and in combination with other IVIM parameters. METHODS: Male Sprague-Dawley rats were used. The rat number was 5, 5, 5, and 3 respectively, for the timepoints of 7, 14, 21, 28 days post-BDL surgery. 12 rats had partial biliary duct recanalization performed after the rats had BDL for 7 days and then again followed-up for a mean of 14 days. Liver diffusion MRIs were acquired at 3.0 T with a b-value distribution of 0, 25, 50, 75, 100, 150, 300, 700, 1000 s/mm2. DDVDmean (control rats n = 6) was the mean of DDVD(b0b25) and DDVD(b0b50). IVIM fitting started from b = 0 s/mm2 with segmented fitting and a threshold b of 50 s/mm2 (n = 5 for control rats). Three 3-D spaces were constructed using a combination of the four diffusion parameters. RESULTS: The control rats and BDL rats (n = 18) had a liver DDVDmean of 84.0 ± 26.2 and 44.7 ± 14.4 au/pixel (p < 0.001). All 3-D spaces totally separated healthy livers and all fibrotic livers (n = 30, BDL rats and recanalization rats). The mean relative distance between healthy liver cluster and fibrotic liver cluster was 0.331 for PF, Dslow, and Dfast; 0.381 for PF, Dfast, and DDVDmean; and 0.384 for PF, Dslow, and DDVDmean. CONCLUSION: A combination of PF, Dslow, and Dfast allows total separation of healthy livers and fibrotic livers and the integration of DDVD improved the separation.

6.
Mar Drugs ; 19(10)2021 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-34677441

RESUMO

To enlarge the chemical diversity of Eurotium sp. SCSIO F452, a talented marine-derived fungus, we further investigated its chemical constituents from a large-scale fermentation with modified culture. Four pairs of new salicylaldehyde derivative enantiomers, euroticins F-I (1-4), as well as a known one eurotirumin (5) were isolated and characterized. Compound 1 features an unprecedented constructed 6/6/6/5 tetracyclic structures, while 2 and 3 represent two new types of 6/6/5 scaffolds. Their structures were established by comprehensive spectroscopic analyses, X-ray diffraction, 13C NMR, and electronic circular dichroism calculations. Selected compounds showed significant inhibitory activity against α-glucosidase and moderate cytotoxic activities against SF-268, MCF-7, HepG2, and A549 cell lines.

7.
Chem Commun (Camb) ; 57(79): 10242-10245, 2021 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-34528040

RESUMO

Iminyl radicals are reactive intermediates that can be used for the construction of various valuable heterocycles. Herein, the electrochemical decarboxylation of α-imino-oxy acids for the generation of iminyl radicals has been accomplished under exogenous-oxidant- and metal-free conditions through the use of nBu4NBr as a mediator. The resulting iminyl radicals undergo intramolecular cyclization smoothly with the adjacent (hetero)arenes to afford a series of indole-fused polycyclic compounds.

8.
J Phys Chem Lett ; 12(39): 9429-9435, 2021 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-34554749

RESUMO

Decoupling the ion motion and segmental relaxation is significant for developing advanced solid polymer electrolytes with high ionic conductivity and high mechanical properties. Our previous work proposed a decoupled ion transport in a novel protein-based solid electrolyte. Herein, we investigate the detailed ion interaction/transport mechanisms through first-principles density functional theory (DFT) calculations in a vacuum space. Specifically, we study the important roles of charged amino acids from proteins. Our results show that the charged amino acids (i.e., Arg and Lys) can strongly lock anions (ClO4-). When locked at a proper position (determined from the molecular structure of amino acids), the anions can provide additional hopping sites and facilitate Li+ transport. The findings are supported from our experiments of two protein solid electrolytes, in which the soy protein (with plenty of charged amino acids) electrolyte shows much higher ionic conductivity and lower activation energy in comparison to the zein (lack of charged amino acids) electrolyte.

9.
Artigo em Inglês | MEDLINE | ID: mdl-34554361

RESUMO

OBJECTIVES: To examine the association between modifiable lifestyle factors and the main semen parameter values, the number of qualified sperm donors, and to provide some sensible guidance for sperm donors. METHODS: Healthy men screened as potential sperm donors were recruited in the Hunan Province Human Sperm Bank of China from March 2019 to December 2019. Participants were invited to complete interviewer-assisted questionnaires on eleven items of information. Univariate and multivariate analyses were conducted to analyze which lifestyle factors collected by the questionnaire had an impact on the eligibility and main semen parameters of sperm donors. RESULTS: The eligibility of men as sperm donors was strongly influenced by the duration of abstinence (P = 0.002). The rate of eligibility sperm donors increased significantly with the number of days of abstinence. In addition, semen volume increased with abstinence time (P = 0.000). Exercise frequency (P = 0.025) and abstinence time (P = 0.000) were positively correlated with sperm concentration, and masturbation frequency was negatively correlated with sperm concentration (P = 0.013). Progressive sperm motility was significantly affected by abstinence time (P = 0.000) and bedtime (P = 0.047). CONCLUSIONS: Abstinence time was highly associated with semen parameters and donor qualification. Increase the abstinence time before donation may be meaningful in improving the proportion of eligible sperm donors.

10.
PLoS Genet ; 17(9): e1009760, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34491994

RESUMO

Unisexual taxa are commonly considered short-lived as the absence of meiotic recombination is supposed to accumulate deleterious mutations and hinder the creation of genetic diversity. However, the gynogenetic gibel carp (Carassius gibelio) with high genetic diversity and wide ecological distribution has outlived its predicted extinction time of a strict unisexual reproduction population. Unlike other unisexual vertebrates, males associated with supernumerary microchromosomes have been observed in gibel carp, which provides a unique system to explore the rationales underlying male occurrence in unisexual lineage and evolution of unisexual reproduction. Here, we identified a massively expanded satellite DNA cluster on microchromosomes of hexaploid gibel carp via comparing with the ancestral tetraploid crucian carp (Carassius auratus). Based on the satellite cluster, we developed a method for single chromosomal fluorescence microdissection and isolated three male-specific microchromosomes in a male metaphase cell. Genomic anatomy revealed that these male-specific microchromosomes contained homologous sequences of autosomes and abundant repetitive elements. Significantly, several potential male-specific genes with transcriptional activity were identified, among which four and five genes displayed male-specific and male-biased expression in gonads, respectively, during the developmental period of sex determination. Therefore, the male-specific microchromosomes resembling common features of sex chromosomes may be the main driving force for male occurrence in gynogenetic gibel carp, which sheds new light on the evolution of unisexual reproduction.

11.
J Cell Mol Med ; 25(20): 9609-9616, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34545688

RESUMO

Hirschsprung disease (HSCR) is an infrequent congenital intestinal dysplasia. The known genetic variations are unable to fully explain the pathogenesis of HSCR. The α/ß-hydratase domain 1 (ABHD1) interferes with the proliferation and migration of intestinal stem cells. Docking protein 6 (DOK6) is involved in neurodevelopment through RET signalling pathway. We examined the association of ABHD1 and DOK6 genetic variants with HSCR using 1470 controls and 1473 HSCR patients from Southern Chinese children. The results clarified that DOK6 rs12968648 G allele significantly increased HSCR susceptibility, in the allelic model (p = 0.034; OR = 1.12, 95%CI = 1.01~1.24) and the dominant model (p = 0.038; OR = 1.12, 95%CI = 1.01~1.25). Clinical stratification analysis showed that rs12968648 G allele was associated with increased risk of short-segment HSCR (S-HSCR), in the allelic model (p = 0.028; OR = 1.14, 95%CI = 1.01~1.28) and the additive model (p = 0.030; OR = 1.14, 95%CI = 1.01~1.28). ABHD1 rs2304678 C allele had higher risk to develop total colonic aganglionosis (TCA) in the allelic model (p = 7.04E-03; OR = 1.67, 95%CI = 1.15~2.43) and the dominant model (p = 4.12E-03; OR = 1.93, 95%CI = 1.23~3.04). DOK6 rs12968648 and ABHD1 rs2304678 had significant intergenic synergistic effect according to logical regression (p = 0.0081; OR = 0.76, 95%CI = 0.63~0.93) and multifactor dimensionality reduction (MDR, p = 0.0045; OR = 1.25, 95%CI = 1.07~1.46). This study verified two susceptible variations of HSCR on ABHD1 and DOK6. Their roles in HSCR should be conducted in further studies.

12.
Inorg Chem ; 60(19): 14540-14543, 2021 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-34515468

RESUMO

Ternary nanomaterials Cu-Cu2O/rGO-NH2 (rGO = reduced graphene oxide) exhibited a synergistic effect in the quantitative catalysis of selective aerobic oxidation of benzyl alcohol. The synergistic effect is attributed to the heterojunctions among the three components and in intrinsic nature, the formation of the heterojunctions lowered the conduction band (CB) energy level and raised the valence band (VB) energy level of the main catalyst Cu2O, which eases electron transfer from the catalyst to O2 in its activation and from the substrate to the catalyst in the oxidation, respectively.

13.
Transl Pediatr ; 10(8): 2076-2082, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34584878

RESUMO

Background: Postoperative cholangitis (PC) is the most common and serious complication of biliary atresia (BA) patients post-Kasai portoenterostomy (KPE). The duration of prophylactic intravenous antibiotics (IVA) after KPE varies with no clear consensus. We conducted a retrospective cohort study to explore the effects of IVA duration on preventing post-operative cholangitis and analyze the risk factors for cholangitis and short-term prognosis. Methods: All patients diagnosed with BA and received KPE in Guangzhou Women and Children's Hospital in 2018, were included in this study. The patients received prophylactic IVA after KPE. Firstly, the patients were divided into two groups based on the presence or absence of PC (PC and NPC group). The correlation between PC and the IVA duration was analyzed, followed by a comparison of short-term prognosis, outcome, and other risk factors between the groups. Next, the patients were divided based on the median IVA duration of 11 days (long IVA and short IVA group), followed by a comparison of the incidence of PC, short-term prognosis, outcome, and other risk factors between the two groups. Results: Totally 89 patients were included in this study. Amount them, eleven patients who were lost during follow-up, were excluded from the study. The prophylactic IVA duration of the PC (n=52) and NPC (n=25) groups was 12.6±8.5 and 13.0±4.5 days, respectively (P=0.79). Further, the jaundice clearance rate of the two groups was similar (PC: 31/52, NPC: 13/25, P=0.53). There was no difference in the incidence and frequency of cholangitis between the short (n=42) and long (n=35) IVA groups (27/42, 25/35, P=0.51), and the duration of IVA had no effect on jaundice clearance (24/42, 20/35, P=1.00). The short IVA group had a significantly shorter hospital stay than the long IVA group (16.2±5.1, 25.3±8.3, P=8.95×10-8). Patients undergoing KPE at an older age were at a higher risk of cholangitis (NPC: 60.6±19.7, PC: 72.3±17.8, P=0.01). Conclusions: A long duration of IVA after KPE for BA may not be necessary. Early diagnosed patients had timely surgery had a lower incidence of PC. Our findings may help in promoting the scientific use of antibiotics and reducing the LHS.

14.
Brain Res Bull ; 176: 151-160, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34500038

RESUMO

BACKGROUND: Bone marrow-derived mesenchymal stem cells (BMSCs) transplantation has been demonstrated to benefit functional recovery after ischemic stroke, however, the low survival rate of BMSCs in ischemic microenvironment largely limits its use. METHODS: Rat BMSCs (rBMSCs) were isolated from SD rats and treated with oxygen glucose deprivation/reoxygenation (OGD) to mimic ischemic microenvironment in vitro. Expression of mRNAs and proteins were assessed by qRT-PCR and western blot, respectively. Cell viability was detected using MTT. ROS level was evaluated by DCFH-DA Assay Kit. TUNEL and flow cytometry analysis were adopted to detect cell apoptosis. Immunofluorescence analysis was used to examine LC3 expression. Dual-luciferase reporter and ChIP assays were employed to determine the interaction between CREG and GATA3. Middle cerebral artery occlusion (MCAO) model was established to mimic ischemic stroke in vivo. TTC staining was used to measure the infarcts area in the brain of MCAO rats. Nissl staining was used to examine the quantity of neurons, and mNSS test was applied to compare behavioral functions of animals. RESULTS: The rBMSCs were successfully isolated from SD rats. OGD exposure decreased the expression of GATA3 in rBMSCs, GATA3 overexpression alleviated OGD-induced cell injury and enhanced autophagy. Treatment with autophagy inhibitor (3-MA) abolished the protective effects of GATA3 against OGD-induced cell injury. GATA3 targeted the promoter of CREG and positively regulated its expression. The protective effect of GATA3 overexpression on autophagy during OGD exposure was reversed by CREG knockdown. Moreover, GATA3 overexpression improved the therapeutic effects of BMSCs transplantation on ischemic stroke in vivo. CONCLUSION: Our results indicated that GATA3 overexpression improved the therapeutic effects of rBMSCs transplantation against ischemic stroke induced injury by regulating autophagy through CREG.

15.
J Transl Med ; 19(1): 400, 2021 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-34551785

RESUMO

BACKGROUND: Cancer stem cells (CSCs) are key regulators in the processes of tumor initiation, progression, and recurrence. The mechanism that maintains their stemness remains enigmatic, although the role of several long noncoding RNAs (lncRNAs) has been highlighted in the pancreatic cancer stem cells (PCSCs). In this study, we first established that PCSCs overexpressing lncRNA NORAD, and then investigated the effects of NORAD on the maintenance of PCSC stemness. METHODS: Expression of lncRNA NORAD, miR-202-5p and ANP32E in PC tissues and cell lines was quantified after RNA isolation. Dual-luciferase reporter assay, RNA pull-down and RIP assays were performed to verify the interactions among NORAD, miR-202-5p and ANP32E. We then carried out gain- and loss-of function of miR-202-5p, ANP32E and NORAD in PANC-1 cell line, followed by measurement of the aldehyde dehydrogenase activity, cell viability, apoptosis, cell cycle distribution, colony formation, self-renewal ability and tumorigenicity of PC cells. RESULTS: LncRNA NORAD and ANP32E were upregulated in PC tissues and cells, whereas the miR-202-5p level was down-regulated. LncRNA NORAD competitively bound to miR-202-5p, and promoted the expression of the miR-202-5p target gene ANP32E thereby promoting PC cell viability, proliferation, and self-renewal ability in vitro, as well as facilitating tumorigenesis of PCSCs in vivo. CONCLUSION: Overall, lncRNA NORAD upregulates ANP32E expression by competitively binding to miR-202-5, which accelerates the proliferation and self-renewal of PCSCs.

16.
Technol Cancer Res Treat ; 20: 15330338211041191, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34520284

RESUMO

Lung cancer is listed as the most common reason for cancer-related death all over the world despite diagnostic improvements and the development of chemotherapy and targeted therapies. MicroRNAs control both physiological and pathological processes including development and cancer. A microRNA-9 to 1 (miR-9 to 1) overexpression model in lung cancer cell lines was established and miR-9 to 1 was found to significantly suppress the proliferation rate in lung cancer cell lines, colony formation in vitro, and tumorigenicity in nude mice of A549 cells. Ubiquitin-like containing PHD and RING finger domains 1 (UHRF1) was then identified to direct target of miR-9 to 1. The inhibition of UHRF1 by miR-9 to 1 causes G1 arrest and p15, p16, and p21 were re-expressed in miR-9 to 1 group in mRNA level and protein level. Silence of UHRF1 expression in A549 cells resulted in the similar re-expression of p15, p16, p21 which is similar with miR-9 to 1 infection. Therefore, we concluded that UHRF1 is a new target for miR-9 to 1 to suppress cell proliferation by re-expression of tumor suppressors p15, p16, and p21 mediated by UHRF1.

17.
Front Immunol ; 12: 702971, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34531856

RESUMO

Polyploidy and subsequent diploidization provide genomic opportunities for evolutionary innovations and adaptation. The researches on duplicated gene evolutionary fates in recurrent polyploids have seriously lagged behind that in paleopolyploids with diploidized genomes. Moreover, the antiviral mechanisms of Viperin remain largely unclear in fish. Here, we elaborate the distinct antiviral mechanisms of two viperin homeologs (Cgviperin-A and Cgviperin-B) in auto-allo-hexaploid gibel carp (Carassius gibelio). First, Cgviperin-A and Cgviperin-B showed differential and biased expression patterns in gibel carp adult tissues. Subsequently, using co-immunoprecipitation (Co-IP) screening analysis, both CgViperin-A and CgViperin-B were found to interact with crucian carp (C. auratus) herpesvirus (CaHV) open reading frame 46 right (ORF46R) protein, a negative herpesvirus regulator of host interferon (IFN) production, and to promote the proteasomal degradation of ORF46R via decreasing K63-linked ubiquitination. Additionally, CgViperin-B also mediated ORF46R degradation through autophagosome pathway, which was absent in CgViperin-A. Moreover, we found that the N-terminal α-helix domain was necessary for the localization of CgViperin-A and CgViperin-B at the endoplasmic reticulum (ER), and the C-terminal domain of CgViperin-A and CgViperin-B was indispensable for the interaction with degradation of ORF46R. Therefore, the current findings clarify the divergent antiviral mechanisms of the duplicated viperin homeologs in a recurrent polyploid fish, which will shed light on the evolution of teleost duplicated genes.

18.
J Colloid Interface Sci ; 606(Pt 2): 1128-1139, 2021 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-34487933

RESUMO

Morphology optimization is an effective strategy to take full advantage of interface polarization for the improvement of electromagnetic wave attenuation capability. Herein, a general route was proposed to produce the flower-like core@shell structured MoS2-based nanocomposites through a simple hydrothermal process. Through the in-situ hydrothermal reaction between the Mo and S sources on the surface of CoNi nanoparticles, flower-like core@shell structured CoNi2S4/Co9S8@MoS2 nanocomposites could be successfully synthesized. By regulating the hydrothermal temperature, the flower-like geometrical morphology of samples could be effectively optimized, and the as-prepared sample (S2) synthesized at 200 °C displayed very excellent flower-like morphology compared to the samples (S1 and S3) obtained at 180 and 220 °C. Owing to the excellent interface polarization effect, the as-prepared S2 presented the evidently superior comprehensive microwave absorption properties in terms of strong aborption capability, wide absorption bandwidth and thin matching thicknesses compared to those of S1 and S3. The as-prepared core@shell structured CoNi2S4/Co9S8@MoS2 sample with very excellent flower-like morphology simultaneously displayed the minimal reflection loss of -50.61 dB with the matching thickness of 2.98 mm, and the effective absorption bandwidth of 8.40 GHz with the matching thickness of 2.36 mm. Therefore, we provided a general route for the production of flower-like core@shell structured MoS2-based nanocomposites, which could make the best of interface polarization to develop high-efficiency microwave absorbers.

19.
Org Biomol Chem ; 19(40): 8789-8793, 2021 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-34585716

RESUMO

The development of electrocatalytic synthetic methods hinges on efficient molecular catalysts. Triarylamines are well-known redox catalysts because of the good stability of their corresponding amine radical cations. Herein we show that tris(4-(tert-butyl)phenyl)amine decomposes unexpectedly during electrolysis in MeOH/THF to afford a tetraarylhydrazine, 1,1,2,2-tetrakis(4-(tert-butyl)phenyl)hydrazine. In addition, we have applied this tetraarylhydrazine, which is either preprepared or formed in situ from tris(4-(tert-butyl)phenyl)amine, as an electrocatalyst for the synthesis of imidazopyridines and related N-heteroaromatic compounds through intramolecular [3 + 2] annulation. This metal-free electrocatalytic method provides straightforward access to the N-heteroaromatic compounds from readily available materials without the need for external chemical oxidants.

20.
Chemosphere ; 287(Pt 1): 131884, 2021 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-34474380

RESUMO

The disposing of municipal solid waste incineration(MSWI) fly ashes containing dioxins is an intractable problems. Co-sintering is one of the most ideal methods to dispose MSWI fly ash, because it not only degrades the dioxins but also makes it possible to re-utilize MSWI fly ashes. In the present study, MSWI fly ash(FA) and water washed MSWI fly ash(WFA) were added into the sinter raw mixture in a lab-scale sintering pot. Different effects of fly ash and water washed fly ash on emission characteristics of dioxins were studied, and possible pathways to form dioxins were discussed in detail. During co-sintering, at least 88.9%, 99.1% of dioxins brought in by FA, WFA was decomposed, respectively, and re-synthesis with a significant distribution characteristic of dioxins originated from sintering process. In the preheating and dry zone, the recombination and condensation reaction of precursors were the main formation pathways of 2,3,7,8-PCDDs in the sintering process and 2,3,7,8-PCDFs were formed by de novo synthesis. In addition, the resynthesis process was affected by chlorine and calcium brought in by fly ash. Sufficient chlorine boosted the chlorination of reactants while calcium increased the residence time, causing the emission concentration of toxic dioxins and the adding ratio were nonlinearly dependent. Therefore, the maximum proportion of water washed MSWI fly ash that can be added into the sintering process was 0.5 wt.%. Besides, the possible pathways to form dioxins were proposed.

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