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1.
J Pharm Biomed Anal ; 210: 114587, 2022 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-35026590

RESUMO

To comply with regulatory requirements, it is necessary to detect and separate the impurities generated during aztreonam synthesis or storage. The chromatogram of aztreonam revealed eight major impurities, which were purified through medium-pressure reversed-phase column and preparative High Performance Liquid Chromatography (HPLC). Through high resolution electrospray ionization mass spectroscopy (HRESIMS), as well as one- and two-dimensional nuclear magnetic resonance (NMR), their structures were confirmed as aztreonam acetate (Ⅰ), desulfated aztreonam (Ⅱ), anti-aztreonam (Ⅲ), open-ring aztreonam (Ⅳ), open-ring desulfated aztreonam (Ⅴ), open-ring desulfated aztreonam ethyl ester (VI), cis-deamino open-ring desulfated aztreonam (VII), and trans-deamino open-ring desulfated aztreonam (Ⅷ). Their exact concentrations were determined through quantitative nuclear magnetic resonance (qNMR) technique. Structural elucidation of the eight impurities through 1H NMR, 13C NMR, the 1H-1H COSY, NOESY, HSQC, HMBC NMR and MS spectra was conducted. Especially, ⅥI and Ⅷ were identified as undescribed impurities here.

2.
Org Biomol Chem ; 2022 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-35048941

RESUMO

In the present study, an efficient Cu-catalyzed transthiolation of alkyl iodides is developed. Notably, in the presence of CO, thioesters could also be obtained with copper and cobalt as the co-catalyst. This transformation displayed good functional group tolerance and afforded thioesters or sulfides from the corresponding alkyl iodides.

3.
Artigo em Inglês | MEDLINE | ID: mdl-35061580

RESUMO

The residue changes of five pesticides in samples from different steps of rice flour production and accelerated storage were systematically investigated. Rice flour was produced both by the extrusion process and the drying on roller process. The change of pesticide residues varied in different processing steps and storage time. The water adjusting step had little influence on the pesticide residues. The pesticide residues were decreased significantly in the extruding, soaking, and grinding steps with reduction from 21% to 76%. The drying step increased or decreased the pesticide residues in varying degrees through concentration due to water evaporation and thermal evaporation or thermal degradation. All the pesticide residues decreased during the accelerated storage, especially for methidathion and chlorpyrifos, neither was detected after accelerated stored for 14 days. The processing factors (PFs) for imidacloprid and isocarbophos in the drying step were greater than 1, and the others were all less than 1. The whole drying on roller process had lower PFs than the whole extrusion process, indicated that the drying on roller process had a greater effect on pesticide residues. The PFs of accelerated storage for five pesticides were all below 1. Overall, this study provides important references for monitoring pesticide residues in the processing and storage of rice flour. Moreover, the PFs obtained in this study could be useful in the dietary exposure and risk assessment of pesticides in rice flour.

4.
ACS Nano ; 2022 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-35023714

RESUMO

Looking for high-performance substrates is an important goal of current surface enhanced Raman scattering (SERS) research. Herein, ultrathin multilayer rhenium (Re) nanosheets as a rare-earth metal substrate are found to have extraordinary SERS performance. These Re nanosheets are prepared through a convenient low-temperature molten salt strategy, and their total thickness is ∼5 nm, including 3-4 layers of ultrathin nanosheets with a thickness of only ∼1 nm. The viscosity of molten salt plays a key role in the formation of these ultrathin layered nanosheets. These nanosheets exhibit a strong and well-defined localized surface plasmon resonance (SPR) effect in the visible light region. The plasmonic Re nanosheets show excellent SERS performance with high sensitivity, chemical stability, and signal repeatability. The lowest detection limit for toxic compounds is 10-12 mol, and the corresponding Raman enhancement factor is 9.1 × 108. A composite enhancement mechanism caused by localized-SPR and charge transport has played an important role in the rare-earth-SERS. High-throughput multiassay analysis is performed on the flexible membrane assembled from the Re nanosheets, which highlights that our system is capable of rapid separation and identification of the samples containing various analytes.

5.
Biomedicines ; 10(1)2022 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-35052864

RESUMO

Ribosome biogenesis is a cellular process critical for protein homeostasis during cell growth and multiplication. Our previous study confirmed up-regulation of ribosome biogenesis during endometriosis progression and malignant transition, thus anti-ribosome biogenesis may be effective for treating endometriosis and the associated complications. A mouse model with human endometriosis features was established and treated with three different drugs that can block ribosome biogenesis, including inhibitors against mTOR/PI3K (GSK2126458) and RNA polymerase I (CX5461 and BMH21). The average lesion numbers and disease frequencies were significantly reduced in treated mice as compared to controls treated with vehicle. Flow cytometry analyses confirmed the reduction of small peritoneal macrophage and neutrophil populations with increased large versus small macrophage ratios, suggesting inflammation suppression by drug treatments. Lesions in treated mice also showed lower nerve fiber density which can support the finding of pain-relief by behavioral studies. Our study therefore suggested ribosome biogenesis as a potential therapeutic target for treating endometriosis.

6.
Cancers (Basel) ; 13(23)2021 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-34884984

RESUMO

Abnormal expression of microRNA miR-214-3p (miR-214) is associated with multiple cancers. In this study, we assessed the effects of CRISPR/Cas9 mediated miR-214 depletion in prostate cancer (PCa) cells and the underlying mechanisms. Knockdown of miR-214 promoted PCa cell proliferation, invasion, migration, epithelial-mesenchymal transition (EMT), and increased resistance to anoikis, a key feature of PCa cells that undergo metastasis. The reintroduction of miR-214 in miR-214 knockdown cells reversed these effects and significantly suppressed cell proliferation, migration, and invasion. These in vitro studies are consistent with the role of miR-214 as a tumor suppressor. Moreover, miR-214 knockout increased tumor growth in PCa xenografts in nude mice supporting its anti-oncogenic role in PCa. Knockdown of miR-214 increased the expression of its target protein, Protein Tyrosine Kinase 6 (PTK6), a kinase shown to promote oncogenic signaling and tumorigenesis in PCa. In addition, miR-214 modulated EMT as exhibited by differential regulation of E-Cadherin, N-Cadherin, and Vimentin both in vitro and in vivo. RNA-seq analysis of miR-214 knockdown cells revealed altered gene expression related to PCa tumor growth pathways, including EMT and metastasis. Collectively, our findings reveal that miR-214 is a key regulator of PCa oncogenesis and is a potential novel therapeutic target for the treatment of the disease.

7.
Nanomaterials (Basel) ; 11(12)2021 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-34947677

RESUMO

In this work, AlGaN-based deep-ultraviolet (DUV) light-emitting diodes (LEDs) with AlGaN as the dielectric layers in p+-Al0.55Ga0.45N/AlGaN/n+-Al0.55Ga0.45N polarization tunnel junctions (PTJs) were modeled to promote carrier tunneling, suppress current crowding, avoid optical absorption, and further enhance the performance of LEDs. AlGaN with different Al contents in PTJs were optimized by APSYS software to investigate the effect of a polarization-induced electric field (Ep) on hole tunneling in the PTJ. The results indicated that Al0.7Ga0.3N as a dielectric layer can realize a higher hole concentration and a higher radiative recombination rate in Multiple Quantum Wells (MQWs) than Al0.4Ga0.6N as the dielectric layer. In addition, Al0.7Ga0.3N as the dielectric layer has relatively high resistance, which can increase lateral current spreading and enhance the uniformity of the top emitting light of LEDs. However, the relatively high resistance of Al0.7Ga0.3N as the dielectric layer resulted in an increase in the forward voltage, so much higher biased voltage was required to enhance the hole tunneling efficiency of PTJ. Through the adoption of PTJs with Al0.7Ga0.3N as the dielectric layers, enhanced internal quantum efficiency (IQE) and optical output power will be possible.

8.
Nutr Metab (Lond) ; 18(1): 106, 2021 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-34922572

RESUMO

BACKGROUND: Nonalcoholic fatty liver disease (NAFLD) is considered the hepatic component of metabolic syndrome and has attracted widespread attention due to its increased prevalence. Daily dietary management is an effective strategy for the prevention of NAFLD. Quinoa, a nutritious pseudocereal, is abundant in antioxidative bioactive phytochemicals. In the present study, the effects of different amounts of quinoa on the progression of NAFLD and the related molecular mechanism were investigated. METHODS: Male SD rats were simultaneously administered a high fat diet (HF) and different amounts of quinoa (equivalent to 100 g/day and 300 g/day of human intake, respectively). After 12 weeks of the intervention, hepatic TG (triglyceride) and TC (total cholesterol) as well as serum antioxidative parameters were determined, and hematoxylin-eosin staining (H&E) staining was used to evaluate hepatic steatosis. Differential metabolites in serum and hepatic tissue were identified using UPLC-QTOF-MSE. The mRNA expression profile was investigated using RNA-Seq and further verified using real-time polymerase chain reaction (RT-PCR). RESULTS: Low amounts of quinoa (equivalent to 100 g/d of human intake) effectively controlled the weight of rats fed a high-fat diet. In addition, quinoa effectively inhibited the increase in hepatic TG and TC levels, mitigated pathological injury, promoted the increase in SOD and GSH-Px activities, and decreased MDA levels. Nontarget metabolic profile analysis showed that quinoa regulated lipid metabolites in the circulation system and liver such as LysoPC and PC. RNA-Seq and RT-PCR verification revealed that a high amount of quinoa more effectively upregulated genes related to lipid metabolism [Apoa (apolipoprotein)5, Apoa4, Apoc2] and downregulated genes related to the immune response [lrf (interferon regulatory factor)5, Tlr6 (Toll-like receptor), Tlr10, Tlr11, Tlr12]. CONCLUSION: Quinoa effectively prevented NAFLD by controlling body weight, mitigating oxidative stress, and regulating the lipid metabolic profile and the expression of genes related to lipid metabolism and the immune response.

9.
Adv Mater ; : e2105761, 2021 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-34655116

RESUMO

The working principle of the triboelectric nanogenerator (TENG), contact electrification and electrostatic induction, has been used to harvest raindrop energy in recent years. However, the existing research is mainly concentrated on solid-liquid electrification, and adopts traditional electrostatic induction (TEI) for output. As a result, the efficiency of droplet electricity generators (DEGs) is severely constrained. Therefore, previous studies deem that the DEG output is limited by interfacial effects. This study reveals that this view is inappropriate and, in reality, the output strategy is the key bottleneck restricting the DEG performance. Here, a switch effect based on an electric-double-layer capacitor (EDLC) is introduced, and an equivalent circuit model is established to understand its working mechanism. Without pre-charging, a single droplet can generate high voltage over 100 V and the output is directly improved by two-orders of magnitude compared with TEI, which is precisely utilizing the interfacial effect. This work provides insightful perspective and lays solid foundation for DEG applications in large scale.

10.
Anal Chem ; 93(36): 12360-12366, 2021 09 14.
Artigo em Inglês | MEDLINE | ID: mdl-34472338

RESUMO

Facing the complex environment of on-site detection, the development of active substrates with wide-spectrum surface-enhanced Raman scattering (SERS) activity is essential. Herein, we report on the low temperature and reproducible synthesis of plasmonic δ-MoN yolk microspheres by in situ-nitriding amorphous MoO2 microspheres at 500 °C and 1 atm. The yolk-structured δ-MoN exhibits strong and wide-spectrum surface plasmon resonance and SERS effects and can perform highly selective detection for probes with different absorption wavelengths under excitation of 532, 633, and 785 nm lasers, with a limitation of 10-11 M and an enhanced factor of 3.6 × 107. Moreover, the plasmonic δ-MoN yolk microspheres have high environmental durability, which can maintain high sensitivity in strong acid and alkaline solutions.


Assuntos
Análise Espectral Raman , Ressonância de Plasmônio de Superfície , Microesferas
11.
Comput Intell Neurosci ; 2021: 7618828, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34567103

RESUMO

Aircraft, as one of the indispensable transport tools, plays an important role in military activities. Therefore, it is a significant task to locate the aircrafts in the remote sensing images. However, the current object detection methods cause a series of problems when applied to the aircraft detection for the remote sensing image, for instance, the problems of low rate of detection accuracy and high rate of missed detection. To address the problems of low rate of detection accuracy and high rate of missed detection, an object detection method for remote sensing image based on bidirectional and dense feature fusion is proposed to detect aircraft targets in sophisticated environments. On the fundamental of the YOLOv3 detection framework, this method adds a feature fusion module to enrich the details of the feature map by mixing the shallow features with the deep features together. Experimental results on the RSOD-DataSet and NWPU-DataSet indicate that the new method raised in the article is capable of improving the problems of low rate of detection accuracy and high rate of missed detection. Meanwhile, the AP for the aircraft increases by 1.57% compared with YOLOv3.


Assuntos
Aeronaves , Tecnologia de Sensoriamento Remoto
12.
Anal Chem ; 93(37): 12776-12785, 2021 09 21.
Artigo em Inglês | MEDLINE | ID: mdl-34493037

RESUMO

The development of low-cost, biocompatible, and durable high-performance substrates is an urgent issue in the field of surface-enhanced Raman scattering (SERS). Herein, by reducing and exfoliating the TiO2-layered nanoplates in the gas phase, nitrogen-doped titanium monoxide (N-TiO) ultrathin nanosheets composed of 2-3 single layers with a thickness of only ∼1.2 nm are synthesized. Compared with pure TiO, the oxidation resistance of N-TiO is greatly improved, in which the oxidation threshold is significantly increased from 187.5 to 415.6 °C. The N-TiO ultrathin nanosheets are found to have strong surface plasmon resonance in the visible region. These ultrathin N-TiO nanosheets can be easily assembled into a large-scale flexible membrane and exhibit remarkable SERS effects. Moreover, this low-cost flexible SERS substrate combines the high durability of noble-metal substrates and the high biocompatibility of semiconductor substrates.


Assuntos
Análise Espectral Raman , Titânio , Óxido Nítrico , Nitrogênio , Ressonância de Plasmônio de Superfície
13.
Soft Matter ; 17(39): 8973-8981, 2021 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-34558595

RESUMO

The network structure in the amorphous domain of swollen iodine-doped poly(vinyl alcohol) (PVA) was systematically investigated by low-field (LF) NMR techniques to reveal the PVA-iodine complex formation mechanism. Three PVA-iodine complexes were obtained under different iodine concentrations (ciodine) of KI/I2 solution: (i) ciodine < 0.1 M: PVA-I3-/I5- complex only exists in the non-crystalline region, (ii) 0.1 M < ciodine < 1 M: formation of PVA-I3- complex I, and (iii) ciodine > 1 M: formation of PVA-I3- complex II. It was found that there is no intermediate-magnitude chain motion of PVA under dyeing conditions to induce the substance exchange, as evidenced by the unchanged second moment M2 (∼1.2 × 104 m s-2) at elevated temperature (<380 K). The introduction of iodine ions can affect the chain mobility of the interphase and mobile regions. With increasing ciodine, the chain dynamics become more restricted, as detected by the faster decay of the T2 relaxometry results, which further accelerates the complexation process. The residual dipolar coupling strength, Dres, obtained by the more quantitative double-quantum (DQ) NMR, increases abruptly at ciodine > 1 M. This suggests more constraints form in the amorphous network for the PVA-I3- complex II system. The constant defects fraction further reveals that the complexation prefers to happen along the tie chains. These results supply a possible formation pathway for the PVA-iodine complexes.

14.
Sci Total Environ ; 801: 149775, 2021 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-34467914

RESUMO

Data on long-chain chlorinated paraffins (LCCPs) is extremely sparse, despite their use and emission are increasing with the phasing out of short-chain chlorinated paraffins (SCCPs). In this study, we analyzed chlorinated paraffins (CPs) in foodstuff samples (551 pooled samples, 93 items) divided into eight categories collected from Jinan, Shandong Province of China, by atmospheric-pressure chemical ionization quadrupole time-of-flight mass spectrometry (APCI-qToF-MS), to investigate the occurrence, contamination patterns and homologue patterns of LCCPs in foodstuff commonly consumed in traditional Chinese diet. LCCP intake through diet was estimated as well. LCCPs were detected in all pooled samples with geometric mean (GM) concentrations ranging from 1.8 to 21.9 ng/g wet weight (ng/g ww), contributing to 9-28% of the total CP mass in the studied foodstuff categories. The contamination patterns of LCCPs differed from SCCPs and medium-chain chlorinated paraffins (MCCPs), as reflected by the patterns of mass distribution, and by the lack of correlations between LCCP and S/MCCP concentrations in various foodstuff categories. The homologue profiles of LCCPs were extremely complex and diverse, with frequent detection of C30-36Cl2-15 very-long-chain chlorinated paraffin (vLCCP) congeners. The homologue profiles of eggs stood out for their high abundance of C18-22Cl9-13 LCCP congeners. LCCPs contributed 6.0-25.2% (8.9% for median estimation) to the estimated dietary intake (EDI) for total CPs through diet based on estimations using different percentiles of CP concentrations. The median estimate of dietary LCCP intake for adults in Jinan was 287.9 ng/kg_bw/day, reaching ~10- to 100-fold of that in Sweden and Canada. Considering the continuing production, use and emission of LCCPs, as well as the similar toxicity effects induced by LCCPs as SCCPs and MCCPs, attention should be paid to the health risk posed by LCCPs, or all CPs as a class of contaminants.


Assuntos
Hidrocarbonetos Clorados , Parafina , China , Contaminação de Medicamentos , Monitoramento Ambiental , Hidrocarbonetos Clorados/análise , Parafina/análise
15.
Nano Lett ; 21(18): 7724-7731, 2021 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-34477392

RESUMO

The synthesis of metallic transition metal nitrides (TMNs) has traditionally been performed under harsh conditions, which makes it difficult to prepare TMNs with high surface area and porosity due to the grain sintering. Herein, we report a general and rapid (30 s) microwave synthesis method for preparing TMNs with high specific surface area (122.6-141.7 m2 g-1) and porosity (0.29-0.34 cm3 g-1). Novel single-crystal porous WN, Mo2N, and V2N are first prepared by this method, which exhibits strong surface plasmon resonance, photothermal conversion, and surface-enhanced Raman scattering effects. Different from the conventional low-temperature microwave absorbing media such as water and polymers, as new concept absorbing media, hydrated metal oxides and metallic metal oxides are found to have a remarkable high-temperature microwave heating effect and play key roles in the formation of TMNs. The current research results provide a new-concept microwave method for preparing high lattice energy compounds with high specific surface.

16.
Cell Signal ; 86: 110105, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34358647

RESUMO

Esophageal squamous cell carcinoma (ESCC) is a deadly disease and one of the most aggressive cancers of the gastrointestinal tract. As a master transcription factor regulating the stress response, NRF2 is often mutated and becomes hyperactive, and thus causes chemo-radioresistance and poor survival in human ESCC. There is a great need to develop NRF2 inhibitors for targeted therapy of NRF2high ESCC. In this review, we mainly focus on three aspects, NRF2 inhibitors and their mechanisms of action, screening novel drug targets, and evaluation of NRF2 activity in the esophagus. A research strategy has been proposed to develop NRF2 inhibitors using human ESCC cells and mouse models.

17.
Front Genet ; 12: 654826, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34413873

RESUMO

Acute myeloid leukemia (AML) is a malignant tumor of the hematopoietic system, and leukemia stem cells are responsible for AML chemoresistance and relapse. KG-1a cell is considered a leukemia stem cell-enriched cell line, which is resistant to chemotherapy. Arsenic trioxide (ATO) is effective against acute promyelocytic leukemia as a first-line treatment agent, even as remission induction of relapsed cases. ATO has a cytotoxic effect on KG-1a cells, but the mechanism remains unclear. Our results demonstrated that ATO can inhibit cell proliferation, induce apoptosis, and arrest KG-1a cells in the G2/M phase. Using transcriptome analysis, we investigated the candidate target genes regulated by ATO in KG-1a cells. The expression profile analysis showed that the ATO had significantly changed gene expression related to proliferation, apoptosis, and cell cycle. Moreover, MYC, PCNA, and MCM7 were identified as crucial hub genes through protein-protein interaction network analysis; meanwhile, the expressions of them in both RNA and protein levels are down-regulated as confirmed by quantitative polymerase chain reaction and Western blot. Thus, our study suggests that ATO not only inhibits the expression of MYC, PCNA, and MCM7 but also leads to cell cycle arrest and apoptosis in KG-1a cells. Overall, this study provided reliable clues for improving the ATO efficacy in AML.

18.
Biomed Opt Express ; 12(7): 4293-4307, 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-34457415

RESUMO

We propose a histogram clustering (HC) method to accelerate fluorescence lifetime imaging (FLIM) analysis in pixel-wise and global fitting modes. The proposed method's principle was demonstrated, and the combinations of HC with traditional FLIM analysis were explained. We assessed HC methods with both simulated and experimental datasets. The results reveal that HC not only increases analysis speed (up to 106 times) but also enhances lifetime estimation accuracy. Fast lifetime analysis strategies were suggested with execution times around or below 30 µs per histograms on MATLAB R2016a, 64-bit with the Intel Celeron CPU (2950M @ 2GHz).

19.
J Org Chem ; 86(13): 8797-8804, 2021 07 02.
Artigo em Inglês | MEDLINE | ID: mdl-34142838

RESUMO

Herein, an interesting palladium-catalyzed procedure for the direct carbonylative thiomethylation of aromatic amine derivatives with 4-methylthio-2-butanone is developed. Using 4-methylthio-2-butanone as (methylthio) transfer agent, a variety of corresponding thioesters are obtained with moderate to good yields under base-free condition. In addition, good functional group tolerance can be observed.


Assuntos
Aminas , Paládio , Butanonas , Catálise , Sais
20.
Plant Dis ; : PDIS03210664RE, 2021 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-34010023

RESUMO

Winter wheat cultivar Liangxing 99, which carries gene Pm52, is resistant to powdery mildew at both seedling and adult-plant stages. An F2:6 recombinant inbred line population from cross Liangxing 99 × Zhongzuo 9504 was phenotyped with Blumeria graminis f. sp. tritici isolate Bgt27 at the adult-plant stage in four field tests and the seedling stage in a greenhouse test. The analysis of bulk segregant RNA sequencing (BSR-Seq) identified a single-nucleotide polymorphism-enriched locus, Qaprpm.caas.2B, on chromosome 2BL in the same genomic interval of Pm52 associated with the all-stage resistance (ASR) and Qaprpm.caas.7A on chromosome 7AL associated with the adult-plant resistance (APR) against the disease. Qaprpm.caas.2B was detected in a 1.3 cM genetic interval between markers Xicscl726 and XicsK128 in which Pm52 was placed with a range of logarithm of odd (LOD) values from 28.1 to 34.6, and the phenotype variations explained in terms of maximum disease severity (MDS) ranged from 45 to 52%. The LOD peak of Qaprpm.caas.7A was localized in a 4.6 cM interval between markers XicsK7A8 and XicsK7A26 and explained the phenotypic variation of MDS ranging from 13 to 16%. The results of this study confirmed Pm52 for ASR and identified Qaprpm.caas.7A for APR to powdery mildew in Liangxing 99.

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