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1.
J Clin Virol ; 173: 105688, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38776575

RESUMO

Respiratory pathogens, such as SARS-CoV-2 and influenza A/B, can cause severe illnesses in susceptible individuals. This research evaluated a novel digital microfluidic point-of-care testing platform designed to detect 23 pathogens, comparing its performance to conventional laboratory-based nucleic acid tests. The platform integrates nucleic acid extraction and amplification processes for rapid detection with only 2 min of hands-on time. Performance assays demonstrated that the platform has high sensitivity (87 %-100 %) and specificity (99 %-100 %) for the detection of the evaluated 3 viruses. Additionally, the platform can be adapted for the detection of other respiratory pathogens, aiding in the early diagnosis of respiratory diseases, identifying the source of an outbreak or epidemic, and curbing the spread of the disease.


Assuntos
COVID-19 , Vírus da Influenza A , Vírus da Influenza B , Influenza Humana , Testes Imediatos , SARS-CoV-2 , Sensibilidade e Especificidade , Humanos , Influenza Humana/diagnóstico , Influenza Humana/virologia , COVID-19/diagnóstico , SARS-CoV-2/isolamento & purificação , SARS-CoV-2/genética , Vírus da Influenza B/isolamento & purificação , Vírus da Influenza B/genética , Vírus da Influenza A/isolamento & purificação , Vírus da Influenza A/genética , Microfluídica/métodos , Microfluídica/instrumentação , Sistemas Automatizados de Assistência Junto ao Leito
2.
ChemSusChem ; 17(1): e202301060, 2024 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-37607341

RESUMO

Visible-light-induced halide-exchange between halide perovskite and organohalide solvents has been studied in which photoinduced electron transfer from CsPbBr3 nanocrystals (NCs) to dihalomethane solvent molecules produces halide anions via reductive dissociation, followed by a spontaneous anion-exchange. Photogenerated holes in this process are less focused. Here, for CsPbBr3 in dibromomethane (DBM), we discover that Br radical (Br⋅) is a key intermediate resulting from the hole oxidation. We successfully trapped Br⋅ with reported methods and found that Br⋅ is continuously generated in DBM under visible light irradiation, hence imperative for catalytic reaction design. Continuous Br⋅ formation within this halide-exchange process is active for photocatalytic [3+2] cycloaddition for vinylcyclopentane synthesis, a privileged scaffold in medicinal chemistry, with good yield and rationalized diastereoselectivity. The NC photocatalyst is highly recyclable due to Br-based self-healing, leading to a particularly economic and neat heterogeneous reaction where the solvent DBM also acts as a co-catalyst in perovskite photocatalysis. Halide perovskites, notable for efficient solar energy conversion, are demonstrated as exceptional photocatalysts for Br radical-mediated [3+2] cycloaddition. We envisage such perovskite-induced Br radical strategy may serve as a powerful chemical tool for developing valuable halogen radical-involved reactions.

3.
Food Chem X ; 20: 100923, 2023 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-38144865

RESUMO

The influences of hydrogen peroxide (H2O2) on the storability and metabolism of disease-resistant substances in fresh longan were investigated. Compared to the control samples, H2O2-treated longan exhibited a higher index of fruit disease, pericarp browning, and pulp breakdown, a higher rate of fruit weight loss, but lower chromaticity values (L*, a* and b*) in pericarp appearance, and a lower commercially acceptable fruit rate. Additionally, H2O2-treated longan showed a lower lignin content, lower activities of enzymes including phenylalnine ammonia lyase (PAL), cinnamate 4-hydroxylase (C4H), 4-coumaryl coenzyme A ligase (4-CL), cinnamate dehydrogenase (CAD), peroxidase (POD), chitinase (CHI), and ß-1,3-glucanase (GLU). These data collectively suggest that H2O2 negatively impacted the storability of fresh longan. This can be attributed to H2O2's role in reducing the levels of disease-resistant substances and suppressing the activities of disease-resistant enzymes, implying that H2O2 reduced the postharvest storability of longan by compromising its disease resistance.

4.
Research (Wash D C) ; 6: 0225, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37719049

RESUMO

The clinical efficacy of implanted biomaterials is often compromised by host immune recognition and subsequent foreign body responses (FBRs). During the implantation, biomaterials inevitably come into direct contact with the blood, absorbing blood protein and forming blood clot. Many studies have been carried out to regulate protein adsorption, thus manipulating FBR. However, the role of clot surface fibrin films formed by clotting shrinkage in host reactions and FBR is often ignored. Because of the principle of fibrin film formation being relevant to fibrinogen or clotting factor absorption, it is feasible to manipulate the fibrin film formation via tuning the absorption of fibrinogen and clotting factor. As biological hydroxyapatite reserved bone architecture and microporous structure, the smaller particle size may expose more microporous structures and adsorb more fibrinogen or clotting factor. Therefore, we set up 3 sizes (small, <0.2 mm; medium, 1 to 2 mm; large, 3 to 4 mm) of biological hydroxyapatite (porcine bone-derived hydroxyapatite) with different microporous structures to investigate the absorption of blood protein, the formation of clot surface fibrin films, and the subsequent FBR. We found that small group adsorbed more clotting factors because of more microporous structures and formed the thinnest and sparsest fibrin films. These thinnest and sparsest fibrin films increased inflammation and profibrosis of macrophages through a potential signaling pathway of cell adhesion-cytoskeleton-autophagy, leading to the stronger FBR. Large group adsorbed lesser clotting factors, forming the thickest and densest fibrin films, easing inflammation and profibrosis of macrophages, and finally mitigating FBR. Thus, this study deepens the understanding of the role of fibrin films in host recognition and FBR and demonstrates the feasibility of a strategy to regulate FBR by modulating fibrin films via tuning the absorption of blood proteins.

5.
J Oral Rehabil ; 50(12): 1465-1480, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37665121

RESUMO

BACKGROUND: Pathological maxillary sinus would affect implant treatment and even result in failure of maxillary sinus lift and implant surgery. However, the maxillary sinus abnormalities are challenging to be diagnosed through CBCT images, especially for young dentists or dentists in grassroots medical institutions without systematical education of general medicine. OBJECTIVES: To develop a deep-learning-based screening model incorporating object detection and 'straight-forward' classification strategy to screen out maxillary sinus abnormalities on CBCT images. METHODS: The large area of background noise outside maxillary sinus would affect the generalisation and prediction accuracy of the model, and the diversity and imbalanced distribution of imaging manifestations may bring challenges to intellectualization. Thus we adopted an object detection to limit model's observation zone and 'straight-forward' classification strategy with various tuning methods to adapt to dental clinical need and extract typical features of diverse manifestations so that turn the task into a 'normal-or-not' classification. RESULTS: We successfully constructed a deep-learning model consist of well-trained detector and diagnostor module. This model achieved ideal AUROC and AUPRC of 0.953 and 0.887, reaching more than 90% accuracy at optimal cut-off. McNemar and Kappa test verified no statistical difference and high consistency between the prediction and ground truth. Dentist-model comparison test showed the model's statistically higher diagnostic performance than dental students. Visualisation method confirmed the model's effectiveness in region recognition and feature extraction. CONCLUSION: The deep-learning model incorporating object detection and straightforward classification strategy could achieve satisfying predictive performance for screening maxillary sinus abnormalities on CBCT images.


Assuntos
Aprendizado Profundo , Tomografia Computadorizada de Feixe Cônico Espiral , Humanos , Seio Maxilar/diagnóstico por imagem , Tomografia Computadorizada de Feixe Cônico/métodos , Maxila
6.
Viruses ; 15(9)2023 09 18.
Artigo em Inglês | MEDLINE | ID: mdl-37766353

RESUMO

Monitoring genetic diversity and recent HIV infections (RHIs) is critical for understanding HIV epidemiology. Here, we report HIV-1 genetic diversity and RHIs in blood samples from 190 HIV-positive MMSCs in Zhuhai, China. MMSCs with newly reported HIV were enrolled from January 2020 to June 2022. A nested PCR was performed to amplify the HIV polymerase gene fragments at HXB2 positions 2604-3606. We constructed genetic transmission network at both 0.5% and 1.5% distance thresholds using the Tamura-Nei93 model. RHIs were identified using a recent infection testing algorithm (RITA) combining limiting antigen avidity enzyme immunoassay (LAg-EIA) assay with clinical data. The results revealed that 19.5% (37/190) were RHIs and 48.4% (92/190) were CRF07_BC. Two clusters were identified at a 0.5% distance threshold. Among them, one was infected with CRF07_BC for the long term, and the other was infected with CRF55_01B recently. We identified a total of 15 clusters at a 1.5% distance threshold. Among them, nine were infected with CRF07_BC subtype, and RHIs were found in 38.8% (19/49) distributed in eight genetic clusters. We identified a large active transmission cluster (n = 10) infected with a genetic variant, CRF79_0107. The multivariable logistic regression model showed that clusters were more likely to be RHIs (adjusted OR: 3.64, 95% CI: 1.51~9.01). The RHI algorithm can help to identify recent or ongoing transmission clusters where the prevention tools are mostly needed. Prompt public health measures are needed to contain the further spread of active transmission clusters.


Assuntos
Infecções por HIV , Soropositividade para HIV , HIV-1 , Masculino , Humanos , Infecções por HIV/epidemiologia , HIV-1/genética , China/epidemiologia , Variação Genética
7.
J Transl Med ; 21(1): 416, 2023 06 26.
Artigo em Inglês | MEDLINE | ID: mdl-37365574

RESUMO

BACKGROUND: Recent studies have discovered an emerging role of IL11 in various colitis-associated cancers, suggesting that IL11 mainly promotes tumor cell survival and proliferation in regulating tumorigenesis. Herein we aimed to reveal a novel function of IL-11 through STAT3 signaling in regulating tumor immune evasion. METHODS: AOM/DSS model in Il11-/- and Apcmin/+/Il11-/- mice were used to detect tumor growth and CD8+ T infiltration. STAT1/3 phosphorylation and MHC-I, CXCL9, H2-K1 and H2-D1 expression were detected in MC38 cells and intestine organoids treated with/without recombinant IL11 to explore effect of IL11/STAT3 signaling, with IL11 mutein used to competitively inhibit IL11 and rescue inhibited STAT1 activation. Correlation between IL11 and CD8+ T infiltration was analyzed using TIMER2.0 website. IL11 expression and survival prognosis was analyzed in clinical data of patient cohort from Nanfang Hospital. RESULTS: IL11 is highly expressed in CRC and indicates unfavorable prognosis. IL11 knockout increased CD8+ T cell infiltration and reduced intestinal and colon formation. Tumors were significantly suppressed while MHC-I and CXCL9 expression for CD8+ T infiltration were remarkably increased in the tumor tissues of Apcmin/+/Il11-/- mice or Il11-/- mice induced by AOM/DSS. IL11/STAT3 signaling downregulated MHC-I and CXCL9 by inhibiting IFNγ-induced STAT1 phosphorylation. IL11 mutein competitively inhibit IL11 to upregulate CXCL9 and MHC-I in tumor and attenuated tumor growth. CONCLUSIONS: This study ascribes for a new immunomodulatory role for IL11 during tumor development that is amenable to anti-cytokine based therapy of colon cancer.


Assuntos
Neoplasias do Colo , Interleucina-11 , Camundongos , Animais , Interleucina-11/metabolismo , Interleucina-11/farmacologia , Transdução de Sinais , Neoplasias do Colo/genética , Neoplasias do Colo/patologia , Citocinas/metabolismo , Linfócitos T CD8-Positivos/metabolismo , Fator de Transcrição STAT3/metabolismo
8.
Curr Res Food Sci ; 6: 100496, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37033742

RESUMO

The aims of present works were to explore the difference in pulp breakdown of 'Fuyan' and 'Dongbi' longans and its relationship with cell wall metabolism. Comparison with 'Fuyan' longan fruit, postharvest 'Dongbi' longan fruit showed lower pulp breakdown index, lower activities of PE, PG, cellulase, ß-Gal, XET, and lower expression levels of their corresponding genes. In addition, higher levels of cell wall polysaccharides including ISP, CSP, cellulose and hemicellulose were exhibited in 'Dongbi' longan pulp. These findings implied that, the reduced activities of enzymes and the down-regulated expressions of genes-involved in cell wall disassembly were shown in 'Dongbi' longan pulp, which might reduce the dissolution of polysaccharides and maintain a higher structural integrity in 'Dongbi' longan pulp cell wall, and consequently the mitigated pulp breakdown was displayed in 'Dongbi' longan during storage.

9.
Food Chem ; 398: 133885, 2023 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-35973299

RESUMO

This work studied the difference in pulp breakdown between two cultivars of longan cv. 'Dongbi' and 'Fuyan' from the aspect of metabolisms of lipid and energy. The results reflected that, compared to 'Fuyan' longan, 'Dongbi' longan had higher levels of energy charge, U/S and IUFA, and higher amounts of USFA, PC, PI, ATP and ADP. Moreover, 'Dongbi' longan exhibited lower levels of SFA, PA, AMP and cell membrane permeability. Also, lower PLD, LOX and lipase activities, but higher ATPase activity, lower pulp breakdown index, and better pulp appearance were exhibited in 'Dongbi' longan. These data revealed that the mitigated pulp breakdown in 'Dongbi' longan was due to the comprehensive coordination of metabolisms in lipid and energy through maintaining a higher level of energy, a higher unsaturation degree of fatty acids, delaying the degradation of phospholipids, and better retaining the membrane structural integrity of microsome and entire cell.


Assuntos
Frutas , Sapindaceae , Adenosina Trifosfatases/metabolismo , Frutas/química , Fosfolipídeos/análise , Sapindaceae/metabolismo
10.
Artigo em Inglês | MEDLINE | ID: mdl-36582066

RESUMO

OBJECTIVE: Several circular RNAs are associated with important pathophysiological characteristics of gestational diabetes mellitus (GDM). This study intended to measure the expression of circ-PNPT1 in sera of GDM patients and to expound on its values on pregnancy outcomes.

Methods: About 104 GDM patients and 71 healthy controls were recruited. The expression pattern of serum circ-PNPT1 was measured by reverse transcription-quantitative polymerase chain reaction. The diagnostic efficacy of circ-PNPT1 and fasting blood glucose (FBG) on GDM was evaluated by receiver operating characteristic (ROC) analysis. Parameters of glycolipid metabolism were determined using automatic biochemical analyzers. The correlation between circ-PNPT1 and glycolipid metabolism parameters was analyzed using Pearson analysis. GDM patients were divided into a high expression group and a low expression group based on the median value of circ-PNPT1 expression. Curves of adverse neonatal outcomes were drawn by Log Rank analysis.

Results: GDM patients exhibited higher circ-PNPT1 expression than healthy controls. The area under the ROC curve of circ-PNPT1 diagnosing GDM was 0.9184 and the cut-off value was 1.435 (90.38% sensitivity, 85.92% specificity). Serum circ-PNPT1 expression was positively correlated with FBG, total cholesterol, and triglyceride in GDM patients. Neonates born to GDM patients with high circ-PNPT1 expression were prone to adverse outcomes.

Conclusion: Circ-PNPT1 was highly-expressed in the sera of GDM patients. Circ-PNPT1 affected glycolipid metabolism and its expression had certain reference values on adverse pregnancy outcomes.

11.
Cytokine ; 158: 155976, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-35921790

RESUMO

Long-standing inflammatory bowel disease predisposes to the development of colorectal cancer (CRC). Interleukin (IL) -6, a pivotal link between chronic inflammation and tumor progression, has recently been recognized as a potential therapeutic target. The effect of IL-6 on proliferation and metastasis of CRC by activating the STAT3 pathway has been widely demonstrated in recent years, but few on mediating tumor immune evasion. In this study, we found that IL-6 was remarkably overexpressed in CRC and its elevation was associated with a poor prognosis. We studied CRC tumorigenesis in vivo by inoculating MC38 tumors and induced-CRC model via AOM/DSS (azoxymethane/dextransulfate sodium) in IL-6 deficient (IL-6-/-) and wild-type (WT) mice and found that IL-6-/- mice were less susceptible to develop tumors, compared to WT mice. We detected CD8+ T cells via immunofluorescence and found they exhibit high expression in tumor of IL-6-/- mice. High level of IL-6 was found in colitis model, with down-regulation of MHC-I molecules. In in vitro experiments, we found that IL-6 may act as a negative regulator in IFNγ-STAT1-MHC-I signaling. In addition, vivo trials also confirmed that MHC-I mRNA level was negatively related to the existence of IL-6. Furthermore, the blockade of IL-6 also activated CD8+T-cell accumulation and led to the high PD-L1 expression in CRC, which can sensitize animals to anti-PD-1 therapy. Our study provides a research basis for the significant role of IL-6 in tumor evasion and highlights a novel target to improve the efficacy of immunotherapy.


Assuntos
Neoplasias Colorretais , Interleucina-6/metabolismo , Animais , Linfócitos T CD8-Positivos/metabolismo , Neoplasias Colorretais/metabolismo , Imunoterapia , Camundongos , Transdução de Sinais , Evasão Tumoral
12.
ACS Appl Mater Interfaces ; 14(22): 25357-25365, 2022 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-35609341

RESUMO

Triplet excitons are generally confined within a semiconductor. Hence, solar energy utilization via direct triplet energy transfer (TET) from semiconductors is challenging. TET from lead halide perovskite semiconductors to nearby organic molecules has been illustrated with ultrafast spectroscopy. Direct utilization of solar energy, i.e., visible light, via TET for photocatalysis is an important route but has not yet been demonstrated with lead halide perovskite semiconductors. Here, we show that a photocatalytic reaction, focusing on a 2 + 2 cycloaddition reaction, can been successfully demonstrated via TET from lead halide perovskite nanocrystals (PNCs). The triplet excitons are shown to induce a highly diastereomeric syn-selective 2 + 2 cycloaddition starting from olefins. Such photocatalytic reactions probe the TET process previously only observed spectroscopically. Moreover, our observation demonstrates that bulk-like PNCs (size, >10 nm; PL = 530 nm), in addition to quantum-confined smaller PNCs, are also effective for TET. Our findings may render a new energy conversion pathway to employ PNCs via direct TET for photocatalytic organic synthesis.

13.
J Periodontol ; 93(12): 1951-1960, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-35150132

RESUMO

BACKGROUND: Immediate implant placement in the esthetic area requires comprehensive assessments with nearly 30 quantitative indexes. Most artificial intelligence (AI)-driven measurements of quantitative indexes depend on segmentation or landmark detection, which require extra labeling of images and contain possible intraclass errors. METHODS: For the initial attempt, the method was tested on sagittal root inclination measurement. This study had developed an accurate and efficient end-to-end model incorporating a convolutional neural network (CNN) based on unlabeled cone-beam computed tomography (CBCT) images for immediate implant placement diagnosis and treatment. The model took pretrained ResNeXt101 as the backbone and was constructed based on 2,920 CBCT images with corresponding angles of the tooth axis and bone axis. The performance of our CNN model was evaluated on a separate test set. RESULTS: Our model exhibited high prediction accuracy in sagittal root inclination measurements, as evidenced by the low mean average error of 2.16°, the high correlation coefficient of 0.915 to manual measurement, and the narrow 95% confidence interval shown by Bland-Altman plots. The intraclass correlation coefficient further confirmed the measurement accuracy of our model was comparable with that of junior clinicians. The model took merely 0.001 seconds for each CBCT image, making it highly efficient. To better understand the model's quality, we visualized our end-to-end CNN model through Guided Backpropagation, Grad-CAM, and Guided Grad-CAM, and confirmed its effectiveness in region recognition. CONCLUSIONS: We succeeded in taking the first step in constructing the end-to-end immediate implant placement AI tool through sagittal root inclination measurements without intermediate steps and extra labeling on images.


Assuntos
Inteligência Artificial , Estética Dentária , Tomografia Computadorizada de Feixe Cônico/métodos , Redes Neurais de Computação , Raiz Dentária/diagnóstico por imagem , Processamento de Imagem Assistida por Computador/métodos
14.
Food Chem X ; 12: 100159, 2021 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-34825169

RESUMO

The influence of hydrogen peroxide (H2O2) on the ROS metabolism and its relationship to pulp breakdown of fresh longan cv. Fuyan during storage was evaluated. Contrasted to control fruit, H2O2-treated samples manifested a higher index of pulp breakdown, an enhanced rate of O2 -. generation, and an increased amount of MDA, but lower APX, CAT and SOD activities, reduced expressions of DlAPX, DlCAT and DlSOD, and lower concentrations of total phenolics, flavonoid, AsA, and GSH as well as lower levels of free radicals scavenging capacity. These data revealed that H2O2-induced pulp breakdown of longan was because H2O2 reduced ability of removing ROS but increased ROS generation and accumulation, which promoted peroxidation of cell membrane lipid, and subsequently led to damaging cell membrane structure and breakdown occurrence in pulp of postharvest fresh longan.

15.
BMC Oral Health ; 21(1): 494, 2021 10 04.
Artigo em Inglês | MEDLINE | ID: mdl-34607581

RESUMO

BACKGROUND: To assess the root angle characteristics of maxillary incisors, and to analyze the relationship between the root angle and other implant-related anatomical indices to use the sagittal root angle as an index for immediate implant evaluation and design. METHODS: A random sample consisting of 400 cone-beam computed tomography (CBCT) images and 65 maxillary plaster models were selected for the present study. CBCT and stereolithography (STL) scan images were imported as DICOM files into coDiagnostiX software for matching the hard and soft tissue. The angle between the long axis of the anterior tooth and the corresponding alveolar bone and implant-related hard and soft tissue indices were measured in the sagittal section. Descriptive statistics, frequency analysis, multi-level comparisons, and correlation analyses were performed. RESULTS: The average sagittal root angles were 15° at the central incisor and 19° at the lateral incisor. The root angle in males was significantly larger than that in females, and increased with age. The largest angle, 22.35°, was found in the lateral incisors of the oldest (> 50 years old) male group. The root angle was found to correlate with coronal buccal bone thickness, coronal palatal bone thickness, apical buccal bone thickness, palatal bone thickness, and the below apex bone thickness. CONCLUSIONS: The sagittal root angle could reflect the distribution of other implant-related anatomical indices, which may provide additional reference for the evaluation of immediate implant placement.


Assuntos
Processo Alveolar , Implantes Dentários , Processo Alveolar/diagnóstico por imagem , Tomografia Computadorizada de Feixe Cônico , Feminino , Humanos , Incisivo/diagnóstico por imagem , Masculino , Maxila/diagnóstico por imagem , Pessoa de Meia-Idade , Estudos Retrospectivos
16.
J Am Chem Soc ; 143(30): 11361-11369, 2021 08 04.
Artigo em Inglês | MEDLINE | ID: mdl-34286970

RESUMO

Heterogeneous photocatalysis is less common but can provide unique avenues for inducing novel chemical transformations and can also be utilized for energy transductions, i.e., the energy in the photons can be captured in chemical bonds. Here, we developed a novel heterogeneous photocatalytic system that employs a lead-halide perovskite nanocrystal (NC) to capture photons and direct photogenerated holes to a surface bound transition metal Cu-site, resulting in a N-N heterocyclization reaction. The reaction starts from surface coordinated diamine substrates and requires two subsequent photo-oxidation events per reaction cycle. We establish a photocatalytic pathway that incorporates sequential inner sphere electron transfer events, photons absorbed by the NC generate holes that are sequentially funneled to the Cu-surface site to perform the reaction. The photocatalyst is readily prepared via a controlled cation-exchange reaction and provides new opportunities in photodriven heterogeneous catalysis.

17.
Adv Sci (Weinh) ; 8(18): e2003046, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34250750

RESUMO

Perovskite photovoltaic ABX3 systems are being studied due to their high energy-conversion efficiencies with current emphasis placed on pure inorganic systems. In this work, synchrotron single-crystal diffraction measurements combined with second harmonic generation measurements reveal the absence of inversion symmetry below room temperature in CsPbBr3 . Local structural analysis by pair distribution function and X-ray absorption fine structure methods are performed to ascertain the local ordering, atomic pair correlations, and phase evolution in a broad range of temperatures. The currently accepted space group assignments for CsPbBr3 are found to be incorrect in a manner that profoundly impacts physical properties. New assignments are obtained for the bulk structure: I m 3 ¯ (above ≈410 K), P21 /m (between ≈300 K and ≈410 K), and the polar group Pm (below ≈300 K), respectively. The newly observed structural distortions exist in the bulk structure consistent with the expectation of previous photoluminescence and Raman measurements. High-pressure measurements reveal multiple low-pressure phases, one of which exists as a metastable phase at ambient pressure. This work should help guide research in the perovskite photovoltaic community to better control the structure under operational conditions and further improve transport and optical properties.

18.
Carbohydr Polym ; 242: 116427, 2020 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-32564850

RESUMO

Longan (Dimocarpus longan Lour.) is prone to pulp softening and pulp breakdown, leading to a loss of its nutrients including polysaccharides. ROS is one main factor affecting fruit quality. This work intended to explicate the influences of hydrogen peroxide, acting as a ROS, on pulp softening, pulp breakdown, and cell wall polysaccharides metabolism in longan fruit during storage. Contrasted to the control group, hydrogen peroxide-treated samples exhibited lower firmness, lower amounts of CWM, ISP, CSP, hemicellulose and cellulose, but higher breakdown index, WSP amount, expression levels of DlPG, DlPE, Dlß-Gal, DlCx and DlXET and activities of their corresponding enzymes (PG, PE, ß-Gal, Cx, XET). These results suggested that hydrogen peroxide reduced longan pulp firmness due to the increased gene expression levels and enzymes activities related to cell wall polysaccharide degradation to boost their decomposition, thereby led to the accelerated pulp softening and the expedited pulp breakdown of harvested longans.


Assuntos
Parede Celular/efeitos dos fármacos , Frutas/efeitos dos fármacos , Peróxido de Hidrogênio/farmacologia , Polissacarídeos/metabolismo , Sapindaceae/efeitos dos fármacos , Metabolismo dos Carboidratos/efeitos dos fármacos , Parede Celular/metabolismo , Armazenamento de Alimentos , Frutas/metabolismo , Sapindaceae/metabolismo
19.
Chemistry ; 26(58): 13118-13136, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32533611

RESUMO

Lately, heterogeneous semiconductor materials have been explored as an emerging type of efficient photocatalyst for photoredox organic synthesis. Among these semiconductors, lead halide perovskite materials demonstrate unique properties towards excellent charge separation and charge transfer, extremely long charge carrier migration, high efficiency in visible light absorption, and long excited states lifetimes, etc., as proved in ground-breaking solar cell applications, garnering necessary merits for an efficient catalytic system for photoredox organic reactions. Here, the latest progress in heterogeneous semiconductor materials towards this endeavor is examined, with particular emphasis on lead halide perovskite nanocrystals (NCs) in photocatalytic organic synthesis.

20.
ChemSusChem ; 13(16): 4005-4025, 2020 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-32424894

RESUMO

Artificial photosynthesis has attracted increasing attention due to recent environmental and energy concerns. Metal halide perovskites (MHPs) demonstrating excellent optoelectronic properties have currently emerged as novel and efficient photocatalytic materials. Herein, the structural features of MHPs that are responsible for the photoinduced charge separation and charge migration properties are briefly introduced, and then important and necessary photophysical and photochemical aspects of MHPs related to photoredox catalysis are summarized. Subsequently, the applications of MHPs for solar energy harvesting and photocatalytic conversion, including H2 evolution, CO2 reduction, degradation of organic pollutants, and photoredox organic synthesis, are extensively demonstrated, with a focus on strategies for improving the performance (e.g., selectivity, activity, stability, recyclability, and environmental compatibility) of these MHP-based photocatalytic systems. To conclude, existing challenges and prospects on the future development of MHP-based materials towards photoredox catalysis applications are detailed.

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