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1.
J Lipid Res ; 64(11): 100449, 2023 11.
Artículo en Inglés | MEDLINE | ID: mdl-37734559

RESUMEN

Activation of brown adipose tissue (BAT) contributes to energy dissipation and metabolic health. Although mineralocorticoid receptor (MR) antagonists have been demonstrated to improve metabolism under obesity, the underlying mechanisms remain incompletely understood. We aimed to evaluate the role of BAT MR in metabolic regulation. After 8 weeks of high-fat diet (HFD) feeding, BAT MR KO (BMRKO) mice manifested significantly increased bodyweight, fat mass, serum fasting glucose, and impaired glucose homeostasis compared with littermate control (LC) mice, although insulin resistance and fasting serum insulin were not significantly changed. Metabolic cage experiments showed no change in O2 consumption, CO2 production, or energy expenditure in obese BMRKO mice. RNA sequencing analysis revealed downregulation of genes related to fatty acid metabolism in BAT of BMRKO-HFD mice compared with LC-HFD mice. Moreover, H&E and immunohistochemical staining demonstrated that BMRKO exacerbated HFD-induced macrophage infiltration and proinflammatory genes in epididymal white adipose tissue (eWAT). BMRKO-HFD mice also manifested significantly increased liver weights and hepatic lipid accumulation, an increasing trend of genes related to lipogenesis and lipid uptake, and significantly decreased genes related to lipolytic and fatty acid oxidation in the liver. Finally, the level of insulin-induced AKT phosphorylation was substantially blunted in eWAT but not liver or skeletal muscle of BMRKO-HFD mice compared with LC-HFD mice. These data suggest that BAT MR is required to maintain metabolic homeostasis, likely through its regulation of fatty acid metabolism in BAT and impacts on eWAT and liver.


Asunto(s)
Adipocitos Marrones , Metabolismo Energético , Receptores de Mineralocorticoides , Animales , Ratones , Adipocitos Marrones/metabolismo , Tejido Adiposo Pardo/metabolismo , Dieta Alta en Grasa/efectos adversos , Ácidos Grasos/metabolismo , Glucosa/metabolismo , Insulina/metabolismo , Resistencia a la Insulina/fisiología , Lípidos , Ratones Endogámicos C57BL , Ratones Obesos , Receptores de Mineralocorticoides/genética , Receptores de Mineralocorticoides/metabolismo , Metabolismo Energético/genética
2.
Int J Genomics ; 2022: 6465760, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36419652

RESUMEN

Lower-grade gliomas (LGG) are the most common intracranial malignancies that readily evolve to high-grade gliomas and increase drug resistance. Paraptosis is defined as a nonapoptotic form of programmed cell death, which is gradually focused on patients with gliomas to develop treatment options. However, the specific role of paraptosis in LGG and its correlation is still vague. In this study, we first establish the novel paraptosis-based prognostic model for LGG patients. The relevant data of LGG patients were acquired from The Cancer Genome Atlas database, and we found that LGG patients could be divided into three different clusters based on paraptosis via consensus cluster analysis. Through least absolute shrinkage and selection operator regression analysis and multivariate Cox regression analysis, 10-paraptosis-related gene (PRG) signatures (CDK4, TNK2, DSTYK, CDKN3, CCR4, CASP9, HSPA5, RGR, LPAR1, and PDCD6IP) were identified to separate LGG patients into high- and low-risk subgroups successfully. The Kaplan-Meier analysis and time-dependent receiver-operating characteristic showed that the performances of predicting overall survival (OS) were dramatically high. The parallel results were reappeared and verified by using the Chinese Glioma Genome Atlas and Gene Expression Omnibus databases. Independent prognostic analysis and nomogram construction implied that risk scores could be considered the independent factor to predict OS. Enrichment analysis indicated that immune-related biological processes were generally enriched, and different immune statuses were highly infiltrated in high-risk group. We also confirmed the potential relationship of 10-PRG signatures and drug sensitivity of Food and Drug Administration-approved drugs. In summary, our findings provide a novel knowledge of paraptosis status and crucial direction to further explore the role of PRG signatures in LGG.

3.
Clin Lab ; 68(7)2022 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-35975540

RESUMEN

BACKGROUND: Candida auris is an opportunistic pathogen with multiple drug resistance. Therefore, researchers conducted a meta-analysis to review PCR's ability to diagnose Candida auris to promote the development of accurate Candida auris diagnosis. METHODS: Researchers systematically retrieved relevant articles from PubMed, Cochrane Library, Embase, and Web of Science. Then, researchers extracted the key data required for the study from the selected articles. Meta-DiSc 1.4 was used for the statistical analysis. RevMan 5.3 was employed to assess the quality of the included literature. A funnel plot can appraise whether the included articles have publication bias. RESULTS: Five articles were included in the study. The results suggest that the pooled sensitivity and pooled specificity were 0.94 (95% CI: 0.92 - 0.95) and 0.99 (95% CI: 0.99 - 0.99), respectively. The positive and negative likelyhood ratios were 100.94 (95% CI: 47.51 - 214.47) and 0.07 (95% CI: 0.05 - 0.10), respectively. The diagnostic odds ratio was 1,814.70 (95% CI: 717.30 - 4,591.04), and the area under the SROC curve was 0.9935. Deek's funnel plot indicated that there was no publication bias. CONCLUSIONS: The results of the analysis indicate that PCR can become a valuable technique for the clinical diagnosis of Candida auris due to its excellent performance.


Asunto(s)
Candida auris , Humanos , Oportunidad Relativa , Reacción en Cadena de la Polimerasa , Curva ROC , Sensibilidad y Especificidad
4.
Eur J Med Res ; 27(1): 43, 2022 Mar 21.
Artículo en Inglés | MEDLINE | ID: mdl-35314002

RESUMEN

BACKGROUND: Opportunistic Candida species causes severe infections when the human immune system is weakened, leading to high mortality. METHODS: In our study, bioinformatics analysis was used to study the high-throughput sequencing data of samples infected with four kinds of Candida species. And the hub genes were obtained by statistical analysis. RESULTS: A total of 547, 422, 415 and 405 differentially expressed genes (DEGs) of Candida albicans, Candida glabrata, Candida parapsilosis and Candida tropicalis groups were obtained, respectively. A total of 216 DEGs were obtained after taking intersections of DEGs from the four groups. A protein-protein interaction (PPI) network was established using these 216 genes. The top 10 hub genes (FOSB, EGR1, JUNB, ATF3, EGR2, NR4A1, NR4A2, DUSP1, BTG2, and EGR3) were acquired through calculation by the cytoHubba plug-in in Cytoscape software. Validated by the sequencing data of peripheral blood, JUNB, ATF3 and EGR2 genes were  significant statistical significance. CONCLUSIONS: In conclusion, our study demonstrated the potential pathogenic genes in Candida species and their underlying mechanisms by bioinformatic analysis methods. Further, after statistical validation, JUNB, ATF3 and EGR2 genes were attained, which may be used as potential biomarkers with Candida species infection.


Asunto(s)
Biomarcadores , Candidiasis/diagnóstico , Candidiasis/genética , Candidiasis/fisiopatología , Biología Computacional/métodos , Transducción de Señal/genética , Candida albicans/genética , Candida glabrata/genética , Candida tropicalis/genética , Regulación de la Expresión Génica , Variación Genética , Genotipo , Humanos
5.
Jpn J Infect Dis ; 75(3): 302-308, 2022 May 24.
Artículo en Inglés | MEDLINE | ID: mdl-34853192

RESUMEN

Based on previous studies, we found that Bacillus Calmette-Guérin (BCG) vaccination may play a role in preventing SARS-CoV-2 infection. Therefore, we conducted a meta-analysis to investigate this protective effect. We searched the Embase, PubMed, Web of Science, Cochrane Library, BioRxiv, and MedRxiv databases for studies that evaluated the relationship between BCG vaccination and SARS-CoV-2 infection or COVID-19 disease. The quality of all included studies was assessed using the Risk of Bias in Non-randomized Studies of Interventions and the Agency for Healthcare Research and Quality data tools. Review Manager (Version 5.3) was used to conduct all the data analyses. A total of eight studies were ultimately included in our meta-analysis. Our primary analysis found a significantly lower SARS-CoV-2 infection rate in the BCG vaccination group compared to the control group, with an odds ratio of 0.61, (95% confidence interval 0.39 to 0.95, P = 0.03; I2 = 31%, and P = 0.21, respectively). Our study indicates that BCG vaccination can protect against SARS-CoV-2 infection. However, there is insufficient evidence that BCG vaccination can reduce the severity of COVID-19.


Asunto(s)
COVID-19 , Vacuna BCG , COVID-19/prevención & control , Humanos , SARS-CoV-2 , Vacunación
6.
Jpn J Infect Dis ; 75(2): 183-191, 2022 Mar 24.
Artículo en Inglés | MEDLINE | ID: mdl-34053954

RESUMEN

Xpert Xpress Flu/RSV is a fast and automated real-time nucleic acid amplification tool for detecting influenza virus and respiratory syncytial virus (RSV). The aim of this study was to verify the accuracy of Xpert Xpress Flu/RSV for detecting influenza virus and RSV. PubMed, EMBASE, Cochrane Library, and Web of Science databases were searched up to October 2020. The quality of the original research was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 guidelines. Meta-DiSc 1.4 software was used to analyze the sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio, and summary receiver operating characteristic curve. Deek's funnel plot asymmetry test was used to evaluate the publication bias using the Stata 12.0 software. Ten studies with 25 fourfold tables were included in the analysis. The sensitivity of Xpert Xpress Flu/RSV for detecting influenza A, influenza B, and RSV were 0.97, 0.98, and 0.96, respectively, and the specificities were 0.97, 1.00, and 1.00, respectively. Compared with other common clinical real-time reverse transcription-polymerase chain reaction (RT-PCR), Xpert Xpress Flu/RSV is a valuable tool for diagnosing influenza virus and RSV with high sensitivity and specificity.


Asunto(s)
Virus de la Influenza A , Gripe Humana , Infecciones por Virus Sincitial Respiratorio , Virus Sincitial Respiratorio Humano , Humanos , Virus de la Influenza A/genética , Virus de la Influenza B/genética , Gripe Humana/diagnóstico , Técnicas de Diagnóstico Molecular , Nasofaringe , Infecciones por Virus Sincitial Respiratorio/diagnóstico , Virus Sincitial Respiratorio Humano/genética , Sensibilidad y Especificidad
7.
Org Lett ; 23(21): 8434-8438, 2021 11 05.
Artículo en Inglés | MEDLINE | ID: mdl-34699247

RESUMEN

We report the efficient syntheses of chiral tetrahydroindole pyrazolinones by the asymmetric [3 + 2] cascade cyclizations (indolizations) of simple aniline derivatives with pyrazolinone ketimines as 2C synthons. The chiral phosphoric-acid-catalyzed system uses a concerted π-π interaction/dual H-bond control strategy to catalytically direct the asymmetric aniline, which undergoes a highly chemo-, regio-, and enantioselective [3 + 2] cascade annulation, furnishing a series of optically active tetra-hydroindole pyrazolinones with two contiguous chiral aza-quaternary carbon centers in excellent yields with excellent enantioselectivities. This method features a relatively broad substrate scope for amines and 2-naphthylamines and highlights the emerging value of direct chiral indolizations from simple amine sources in organic synthesis.

8.
Cell Death Dis ; 12(8): 724, 2021 07 21.
Artículo en Inglés | MEDLINE | ID: mdl-34290231

RESUMEN

Glioblastomas (GBM) is the most common primary malignant brain tumor, and radiotherapy plays a critical role in its therapeutic management. Unfortunately, the development of radioresistance is universal. Here, we identified calcium-regulated heat-stable protein 1 (CARHSP1) as a critical driver for radioresistance utilizing genome-wide CRISPR activation screening. This is a protein with a cold-shock domain (CSD)-containing that is highly similar to cold-shock proteins. CARHSP1 mRNA level was upregulated in irradiation-resistant GBM cells and knockdown of CARHSP1 sensitized GBM cells to radiotherapy. The high expression of CARHSP1 upon radiation might mediate radioresistance by activating the inflammatory signaling pathway. More importantly, patients with high levels of CARHSP1 had poorer survival when treated with radiotherapy. Collectively, our findings suggested that targeting the CARHSP1/TNF-α inflammatory signaling activation induced by radiotherapy might directly affect radioresistance and present an attractive therapeutic target for GBM, particularly for patients with high levels of CARHSP1.


Asunto(s)
Neoplasias Encefálicas/genética , Proteína 9 Asociada a CRISPR/metabolismo , Sistemas CRISPR-Cas/genética , Proteínas de Unión al ADN/metabolismo , Genoma Humano , Glioblastoma/genética , Fosfoproteínas/metabolismo , Tolerancia a Radiación/genética , Factores de Transcripción/metabolismo , Neoplasias Encefálicas/patología , Neoplasias Encefálicas/radioterapia , Línea Celular Tumoral , Proteínas de Unión al ADN/genética , Resistencia a Antineoplásicos/genética , Regulación Neoplásica de la Expresión Génica , Glioblastoma/patología , Glioblastoma/radioterapia , Humanos , Fosfoproteínas/genética , ARN Mensajero/genética , ARN Mensajero/metabolismo , Factores de Transcripción/genética , Factor de Necrosis Tumoral alfa/metabolismo , Regulación hacia Arriba/genética
10.
Hum Genomics ; 15(1): 22, 2021 04 19.
Artículo en Inglés | MEDLINE | ID: mdl-33875006

RESUMEN

BACKGROUND: Currently, Chlamydia trachomatis-specific host defense mechanisms in humans remain poorly defined. To study the characteristics of host cells infected early with Chlamydia trachomatis, we used bioinformatics methods to analyze the RNA transcription profiles of the conjunctiva, fallopian tubes, and endometrium in humans infected with Chlamydia trachomatis. METHOD: The gene expression profiles of GSE20430, GSE20436, GSE26692, and GSE41075 were downloaded from the Gene Expression Synthesis (GEO) database. Then, we obtained the differentially expressed genes (DEGs) through the R 4.0.1 software. STRING was used to construct protein-protein interaction (PPI) networks; then, the Cytoscape 3.7.2 software was used to visualize the PPI and screen hub genes. GraphPad Prism 8.0 software was used to verify the expression of the hub gene. In addition, the gene-miRNA interaction was constructed on the NetworkAnalyst 3.0 platform using the miRTarBase v8.0 database. RESULTS: A total of 600 and 135 DEGs were screened out in the conjunctival infection group and the reproductive tract infection group, respectively. After constructing a PPI network and verifying the hub genes, CSF2, CD40, and CSF3 in the reproductive tract infection group proved to have considerable statistical significance. CONCLUSION: In our research, the key genes in the biological process of reproductive tract infection with Chlamydia trachomatis were clarified through bioinformatics analysis. These hub genes may be further used in clinical treatment and clinical diagnosis.


Asunto(s)
Antígenos CD40/genética , Chlamydia trachomatis/genética , Conjuntiva/metabolismo , Factor Estimulante de Colonias de Granulocitos y Macrófagos/genética , Infecciones del Sistema Genital/genética , Chlamydia trachomatis/patogenicidad , Biología Computacional , Conjuntiva/microbiología , Conjuntiva/parasitología , Trompas Uterinas/metabolismo , Trompas Uterinas/microbiología , Trompas Uterinas/patología , Femenino , Redes Reguladoras de Genes/genética , Interacciones Huésped-Patógeno/genética , Humanos , MicroARNs/genética , Mapas de Interacción de Proteínas/genética , Infecciones del Sistema Genital/microbiología , Infecciones del Sistema Genital/patología , Transducción de Señal/genética , Programas Informáticos
11.
RSC Adv ; 11(27): 16510-16521, 2021 Apr 30.
Artículo en Inglés | MEDLINE | ID: mdl-35479169

RESUMEN

The valve replacement is the main treatment of heart valve disease. However, thrombus formation following valve replacement has always been a major clinical drawback. Accelerating the endothelialization of cardiac valve prosthesis is the main approach to reduce thrombus. In the current study, a titanium nanotube was biofunctionalized with a chitosan/genipin heparin hydrogel and the controlled release of interleukin-4 (IL-4), and its regulation of macrophages was investigated to see if it could influence endothelial cells to eventually accelerate endothelialization. TNT60 (titanium dioxide nanotubes, 60 V) with nanoarray was obtained by anodic oxidation of 60 V, and IL-4 was loaded into the nanotube by vacuum drying. The hydrogel (chitosan : genipin = 4 : 1) was applied to the surface of the nanotubes following drying, and the heparin drops were placed on the hydrogel surface with chitosan as the polycation and heparin as the polyanion. A TNT/IL-4/G (G = gel, chitosan/genipin heparin) delivery system was prepared. Our results demonstrated that the biofunctionalization of titanium nanotube with chitosan/genipin heparin hydrogel and the controlled release of IL-4 had a significant regulatory effect on macrophage M2 polarization, reducing the inflammatory factor release and higher secretion of VEGF (vascular endothelial growth factor), which can accelerate the endothelialization of the implant.

12.
Biomed Res Int ; 2020: 2892734, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33102576

RESUMEN

BACKGROUND: Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) are widely spread across the world. Asymptomatic or inconspicuous CT/NG infections are difficult to diagnose and treat. Traditional methods have the disadvantages of low detection rate, inaccurate results, and long detection time. However, Xpert CT/NG makes up for the aforementioned shortcomings and has research value and popularization significance. METHODS: PubMed, Embase, Cochrane Library, and Web of Science were systematically searched, and studies were screened using Xpert CT/NG for diagnosing CT/NG. QUADAS-2 was used to evaluate the quality of the eligible studies. Then, two groups of researchers independently extracted data from these studies. Meta-analyses of sensitivity (SEN), specificity (SPE), positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and the area under the curve (AUC) of the summary receiver operating characteristic (SROC) curve were conducted using Meta-DiSc 1.4. Finally, Deek's funnel plots were made using Stata 12.0 to evaluate publication bias. RESULTS: 14 studies were identified, and 46 fourfold tables were extracted in this meta-analysis. The pooled SEN, SPE, PLR, NLR, DOR, and AUC in diagnosing CT were 0.94 (95% confidence interval (CI): 0.93-0.95), 0.99 (95% CI: 0.99-1.00), 97.17 (95% CI: 56.76-166.32), 0.07 (95% CI: 0.04-0.12), 1857.25 (95% CI: 943.78-3654.86), and 0.9960, respectively. The pooled SEN, SPE, PLR, NLR, DOR, and AUC in diagnosing NG were 0.95 (95% CI: 0.93-0.96), 1.00 (95% CI: 1.00-1.00), 278.15 (95% CI: 152.41-507.63), 0.08 (95% CI: 0.06-0.12), 4290.70 (95% CI: 2161.78-8516.16), and 0.9980, respectively. CONCLUSIONS: Xpert CT/NG had high diagnostic sensitivity and specificity for CT and NG. However, more evidence is required to confirm that Xpert CT/NG might serve as the primary method for detecting CT and NG and even the gold standard for diagnosis in the future.


Asunto(s)
Infecciones por Chlamydia/diagnóstico , Gonorrea/diagnóstico , Área Bajo la Curva , Infecciones por Chlamydia/microbiología , Chlamydia trachomatis/patogenicidad , Gonorrea/microbiología , Humanos , Neisseria gonorrhoeae/patogenicidad , Oportunidad Relativa , Curva ROC , Sensibilidad y Especificidad
13.
J Clin Lab Anal ; 34(7): e23281, 2020 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-32157743

RESUMEN

BACKGROUND: Detection of hepatitis B virus (HBV) is vital for the diagnosis of hepatitis B infection. A novel test loop-mediated isothermal amplification (LAMP) has been successfully applied to detect various pathogens. However, the accuracy of LAMP in diagnosing HBV remains unclear. Therefore, in the present study, the accuracy of LAMP for HBV detection was evaluated systematically. METHODS: Embase, Cochrane Library, and PubMed databases were searched for studies using LAMP to detect HBV. Then, two researchers extracted data and assessed the quality of literature using the QUADAS-2 tool independently. I2 statistic and chi-square test were analyzed to investigate the heterogeneity, and Deek's funnel plot assessed the publication bias. The pooled sensitivity (SEN), specificity (SPE), positive LR (PLR), negative LR (NLR), diagnostic odds ratio (DOR), and 95% confidence intervals were displayed in forest plots. We calculated the area under the curve (AUC) to assess the overall efficiency of LAMP for HBV detection. RESULTS: A total of nine studies with 1298 samples were finally included in this evaluation. The pooled sensitivity and specificity of HBV detection were 0.91 (95% CI: 0.89 ~ 0.92) and 0.97 (95% CI: 0.94 ~ 0.99), respectively. The PLR, NLR, and DOR were 16.93 (95% CI: 6.15 ~ 46.55), 0.08 (95% CI: 0.05 ~ 0.14), and 397.57 (95% CI: 145.41 ~ 1087.07). Besides, the AUC was 0.9872, and Deek's plot suggested that there existed publication bias in the studies. CONCLUSION: Compared with PCR, LAMP is a simple, rapid, and effective assay to diagnose HBV. However, additional evidence is essential to confirm that LAMP can replace other methods in diagnosing HBV infection.


Asunto(s)
Hepatitis B/diagnóstico , Técnicas de Diagnóstico Molecular/métodos , Técnicas de Amplificación de Ácido Nucleico/métodos , Hepatitis B/sangre , Humanos , Control de Calidad , Sensibilidad y Especificidad
14.
Org Lett ; 22(6): 2448-2453, 2020 Mar 20.
Artículo en Inglés | MEDLINE | ID: mdl-32142304

RESUMEN

We have developed a novel π-π interaction and dual H-bond concerted control strategy to construct axially chiral naphthylamine heterocycles. With ortho-alkynyl-naphthylamines as the electrophile, indoles and 4-hydroxycoumarins were efficiently employed to construct axially chiral skeletons in good yields and with excellent enantioselectivities (up to 97% enantiomeric excess). Furthermore, the resulting products could be converted to potential squaramides featuring organic catalysts.

15.
Org Lett ; 22(6): 2173-2177, 2020 03 20.
Artículo en Inglés | MEDLINE | ID: mdl-32141758

RESUMEN

In general, enantioselective C-H functionalization of N-monosubstituted anilines is a highly challenging task owing to the competitive chemoselective N-H bond insertion reactions. In this paper, we reported a direct highly chemo-, site-, and enantioselective para C-H aminoalkylation of N-monosubstituted aniline derivatives with isatin-derived ketimines in the presence of chiral phosphoric acids (CPAs) and offered a practical strategy for para asymmetric C-H functionalization of anilines containing N-H bonds.

16.
Org Lett ; 21(21): 8662-8666, 2019 11 01.
Artículo en Inglés | MEDLINE | ID: mdl-31638819

RESUMEN

A versatile dual H-bonds and π-π interaction strategy that enables enantioselective remote C6-selective C-H functionalization of 2,3-disubstituted indoles was first reported. The N-H bond of indole was pivotal to achieve the C6 functionalization with excellent yield and enantioselectivity. Furthermore, this methodology leads to the efficient construction of numerous enantioenriched C6-functionalized indole products under mild reaction conditions employing different electrophiles. Preliminary cell proliferation investigations revealed that the synthesized chiral C6-substituted indole derivatives had potential anticancer activities.


Asunto(s)
Indoles/química , Ácidos Fosfóricos/química , Catálisis , Enlace de Hidrógeno , Estereoisomerismo
17.
Org Biomol Chem ; 17(37): 8589-8600, 2019 09 25.
Artículo en Inglés | MEDLINE | ID: mdl-31517383

RESUMEN

Herein, a cascade [3 + 2] annulation of N-aryloxyacetamides with 3-(hetero)arylpropiolic acids affording benzofuran-2(3H)-ones via rhodium(iii)-catalyzed redox-neutral C-H functionalization/isomerization/lactonization using an internal oxidative directing group O-NHAc was achieved. This catalytic system provides a regio- and stereoselective approach to synthesize (Z)-3-(amino(aryl)methylene)benzofuran-2(3H)-ones with exclusive Z configuration selectivity, acceptable yields and good functional group tolerance. Preliminary investigations on ultraviolet-visible and fluorescence behaviors reveal that the annulation products may be applied as a promising fluorescent probe for sensing metal cations, especially for cerium (Ce3+).

18.
Anal Chem ; 91(16): 10541-10548, 2019 Aug 20.
Artículo en Inglés | MEDLINE | ID: mdl-31313574

RESUMEN

The photothermally induced resonance AFM-IR technique (denoted as PTIR) is a promising and still developing analytical method that can provide nanoscale chemical and topographical information. Herein, by taking advantage of a customized PTIR system with either top-down or bottom-up incidence mode for a quantum cascade laser (QCL), we explore how the surface-enhanced IR absorption (SEIRA) effect due to the Au-coated AFM tip and/or substrate may affect the PTIR signals from 25 to 580 nm thick p-nitrobenzoic acid (PNBA) samples, as a function of sample thickness, incidence mode, laser polarization, and Au film morphology. By analysis of the νas(NO2) band intensity, it is revealed that the SEIRA effect may increase the PTIR signals by 1.5-8.3 times, with that from the Au-coated substrate being greater than that from the Au-coated tip. Nevertheless, the overall PTIR signal goes up monotonically over the entire thickness range for the top-down incidence mode, while it increases and then decreases with the sample thickness for the bottom-up incidence mode. The p-polarized laser enhances the PTIR signal more than does the s-polarized laser, especially on the Au-coated substrate. The significant loss of the PTIR signal of a PNBA sample corroborates the substantial loss of the SEIRA effect of an annealed Au film. The present work may promote the application of the SEIRA effect to the PTIR technique and provides hints for developing the PTIR technique into a more versatile analytical tool.

19.
Nat Commun ; 10(1): 3063, 2019 07 11.
Artículo en Inglés | MEDLINE | ID: mdl-31296850

RESUMEN

Nonbiaryl N-C atropisomer is an important structural scaffold, which is present in natural products, medicines and chiral ligands. However the direct enantioselective C-H amination to access optically pure N-C atropisomer is still difficult and rare. Here we report a π-π interaction and dual H-bond concerted control strategy to develop the chiral phosphoric acids (CPAs) catalyzed direct intermolecular enantioselective C-H amination of N-aryl-2-naphthylamines with azodicarboxylates as amino sources for the construction of atroposelective naphthalene-1,2-diamines. This type of N-C atropisomers is stabilized by intramolecular hydrogen bond and the method features a broad range of substrates, high yields and ee values, providing a strategy to chirality transfer via the modification of N-C atropisomers.

20.
Org Lett ; 21(8): 2795-2799, 2019 04 19.
Artículo en Inglés | MEDLINE | ID: mdl-30969130

RESUMEN

A method of SPINOL-derived chiral phosphoric acid catalyzed asymmetric intermolecular N-hydroxyalkylation of multisubstituted indoles with ethyl glyoxalates is described in this report. This protocol provides an alternative, convenient, and direct strategy for efficient access to structurally unique α-chiral indole N,O-acyclic aminals with a broad substrate scope and good to excellent enantioselectivities. The synthetic utility of this methodology is illustrated by a gram-scale experiment and the subsequent efficient synthesis of more complex chiral N,O-aminal indole derivatives.

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