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Diagnostic performance of fluorine-18 fluorodeoxyglucose positron emission tomography in the management of solitary pulmonary nodule: a meta-analysis
摘要： Background: In the setting of solitary pulmonary nodules (SPNs), fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT) is considered a useful non-invasive diagnostic tool though false positive (FP) and false negative (FN) results affects accuracy due to different conditions, such as inflammatory diseases or low-uptake neoplasms. Aim of this study is to evaluate overall diagnostic performance of 18F-FDG-PET/CT for malignant pulmonary nodules. Methods: A computerized research, including published articles from 2012 and 2017, was carried out. 18F-FDG-PET/CT overall sensitivity (Se), specificity (Spe), positive likelihood ratio (PLR), negative likelihood ratio (NLR), positive predictive value (PPV), negative predictive value (NPV), diagnostic index and odds ratio were pooled. No selection-bias were found according to asymmetry test. Results: A total of twelve studies were included in the meta-analysis. The pooled Se, Spe, PLR, NLR, PPV, NPV and accuracy index (AI) with relative 95% confidence intervals (CI) were 0.819 (95% CI: 0.794–0.843), 0.624 (95% CI: 0.582–0.665), 2.190 (95% CI: 1.950–2.440), 0.290 (95% CI: 0.250–0.330), 0.802 (95% CI: 0.783–0.819), 0.652 (95% CI: 0.618–0.684) and 0.649 (95% CI: 0.625–0.673), respectively. The diagnostic odds ratio (DOR) was 7.049 with a relative 95% CI between 5.550 and 8.944. Conclusions: The results suggest 18F-FDG-PET/CT has good diagnostic accuracy in SPNs evaluation; but, it should not be considered as a discriminatory test rather than a method to be included in a clinical and diagnostic pathway.
关键词： Fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT),solitary pulmonary nodules (SPNs),lung cancer
更新于2025-09-19 17:15:36
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[Methods in Molecular Biology] Cancer Metabolism Volume 1928 (Methods and Protocols) || Imaging Cancer Metabolism with Positron Emission Tomography (PET)
摘要： Positron emission tomography (PET) enables the noninvasive spatiotemporal analysis of cancer metabolism in vivo. Both natural and nonnatural PET tracers have been developed to assess metabolic pathways during tumorigenesis, cancer progression, and metastasis. Here we describe the dynamic in vivo PET/CT imaging of the glucose analogue [18F]fluoro-2-deoxy-D-glucose (FDG), taking into consideration the methodology for alternative metabolic PET substrates.
关键词： FDG,Fluorine-18,Imaging,Positron emission tomography,PET,Carbon-11,Fluorodeoxyglucose,Mouse
更新于2025-09-19 17:15:36
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Effect of fluorine substituents on benzothiadiazole-based Da????a??Aa?2a????a??A photosensitizers for dye-sensitized solar cells
摘要： Two D–π–A0–π–A organic dyes with triazatruxene (TAT) as the electron donor, thiophene as the π-spacer, benzoic acid as the anchor group, and benzothiadiazole (BT) or difluorobenzo[c][1,2,5]thiadiazole (DFBT) as the additional acceptor, namely LS101 and LS102, respectively, were applied to dye-sensitized solar cells (DSSCs). As fluorine substituents are usually strong electron-withdrawing groups, introducing two fluorine atoms into BT was expected to strengthen the electron-withdrawing ability of the auxiliary acceptor, resulting in DSSCs with a broader light capture region and further improved power conversion efficiency (PCE). Fluorine is the smallest electron-withdrawing group with an induction effect, but can also act as an electron-donating group owing to its conjugation effect. When the conjugation effect is dominant, the electron-withdrawing ability of additional acceptor DFBT decreases instead. Accordingly, the band gap of LS102 was broadened and the UV-vis absorption spectrum was blue-shifted. In the end, DSSCs based on LS101 achieved a champion PCE of 10.2% (Jsc = 15.1 mA cm?2, Voc = 966 mV, FF = 70.1%) while that based on LS102 gave a PCE of only 8.6% (Jsc = 13.4 mA cm?2, Voc = 934 mV, FF = 69.1%) under standard AM 1.5G solar irradiation (100 mW cm?2) with Co2+/Co3+ as the electrolyte.
关键词： Power conversion efficiency,Fluorine substituents,Organic photosensitizers,Benzothiadiazole,Dye-sensitized solar cells
更新于2025-09-19 17:13:59
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Effect of multiple electron-withdrawing substituents on photovoltaic properties of quinoxaline-based polymers
摘要： Two quinoxaline-based polymers, in which the electron-donating 2-octyldodecyl modified benzodithiophene (BDT) group was connected to the electron-accepting 2,3-diphenyl quinoxaline (Qx) through a thiophene bridge, were synthesized by the Stille coupling reaction. The strong electron-withdrawing trifluoromethyl (CF3) substituents were introduced at para-position of the benzene ring at 2,3-positions Qx to yield PBDT-CF3Qx. Moreover, two fluorine atoms were incorporated at the 6,7-positions of Qx in PBDT-CF3Qx to produce PBDT-CF3QxF. This simple approach demonstrate the effect of multiple electron-withdrawing moieties on the optical, electrochemical, and photovoltaic properties of Qx-based polymers.
关键词： quionoxaline,trifluoromethyl,fluorine,electron-withdrawing
更新于2025-09-19 17:13:59
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Synthesis, radiolabelling and initial biological characterisation of <sup>18</sup> F-labelled xanthine derivatives for PET imaging of Eph receptors
摘要： Eph receptor tyrosine kinases, particularly EphA2 and EphB4, represent promising candidates for molecular imaging due to their essential role in cancer progression and therapy resistance. Xanthine derivatives were identified to be potent Eph receptor inhibitors with IC50 values in the low nanomolar range (1–40 nm). These compounds occupy the hydrophobic pocket of the ATP-binding site in the kinase domain. Based on lead compound 1, we designed two fluorine-18-labelled receptor tyrosine kinase inhibitors ([18F]2/3) as potential tracers for positron emission tomography (PET). Docking into the ATP-binding site allowed us to find the best position for radiolabelling. The replacement of the methyl group at the uracil residue ([18F]3) rather than the methyl group of the phenoxy moiety ([18F]2) by a fluoropropyl group was predicted to preserve the affinity of the lead compound 1. Herein, we point out a synthesis route to [18F]2 and [18F]3 and the respective tosylate precursors as well as a labelling procedure to insert fluorine-18. After radiolabelling, both radiotracers were obtained in approximately 5% radiochemical yield with high radiochemical purity (>98%) and a molar activity of >10 GBq μmol?1. In line with the docking studies, first cell experiments revealed specific, time-dependent binding and uptake of [18F]3 to EphA2 and EphB4-overexpressing A375 human melanoma cells, whereas [18F]2 did not accumulate at these cells. Since both tracers [18F]3 and [18F]2 are stable in rat blood, the novel radiotracers might be suitable for in vivo molecular imaging of Eph receptors with PET.
关键词： xanthine derivatives,molecular imaging,positron emission tomography (PET),fluorine-18-labelled,Eph receptor tyrosine kinases
更新于2025-09-19 17:13:59
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Fluorine-containing graphene quantum dots with a high singlet oxygen generation applied for photodynamic therapy
摘要： Recently, graphene quantum dots (GQDs) have been extensively studied in biomedical areas such as bio-imaging, bio-sensing and photothermal therapy due to their superior optical and physiochemical properties compared to traditional organic biomarkers. Application of GQDs in photodynamic therapy (PDT) has been explored since 2014, but currently the main challenges are inadequate singlet oxygen (1O2) quantum yield (QY), poor solubility and biocompatibility. Herein, we report on the synthesis of a new kind of fluorine-containing GQDs (F-GQDs) by an oxidative cutting method using fluorinated graphite as the raw material. The as-synthesized F-GQDs sample demonstrates an average particle size of 2.1 nm with the fluorine doping content of 1.43%. The F-GQDs have a more excellent water solubility and biocompatibility than the GQDs, and emit strong green fluorescence at 365 nm excitation with the relative fluorescence QY of 13.72%. Moreover, the fluorescence imaging effect as well as photodynamic activity successfully tested in both in vitro HepG2 cell line model and a 3D multicellular spheroids model that mimics the tumour microenvironment. Further studies using UV-visible spectroscopy through the degradation of water-soluble 9,10-anthracenediyl-bis(methylene) dimalonic acid(ABDA) demonstrate that the F-GQDs sample generate 1O2 efficiently (QY = 0.49) under a visible light irradiation. Compared to non-fluorinated GQDs, the as-reported F-GQDs manifest to be a more promising photosensitizer for image-guided PDT.
关键词： singlet oxygen,photodynamic therapy,biocompatibility,fluorine-containing,graphene quantum dots
更新于2025-09-19 17:13:59
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Tetrafluoroethylene as a fuel component for an atomic fluorine generator of a supersonic continuous-wave chemical HF laser
摘要： A cheap and widely accessible combination (one of non-saturated perfluorocarbons), i.e. C2F4 tetrafluoroethylene, is proposed as an alternative fuel component for an atomic fluorine generator of a supersonic cw chemical HF laser of self-contained type. Combustion products of the hypergolic F2 – C2F4 – He mixture do not contain active relaxants of vibrationally excited HF(u) molecules. According to estimates, the atomic fluorine yield under comparable conditions is about 70 % in relation to that of the atomic fluorine generator operating on the F2 – D2 – He mixture which is the ‘basic’ one for a HF laser. The specific power is reduced by 23 % with an improvement in a set of the fuel performance and a significant reduction in the cost of triggering the laser in the course of its bench tests.
关键词： supersonic cw chemical HF laser,tetrafluoroethylene,atomic fluorine generator
更新于2025-09-16 10:30:52
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Fluorine Tuning of Morphology, Energy Loss, and Carrier Dynamics in Perylenediimide Polymer Solar Cells
摘要： We investigate backbone fluorination effects in bulk-heterojunction (BHJ) polymer solar cells (PSCs) with the fluorine-poor PBDTT-FTTE and fluorine-rich PBDTTF-FTTE donor polymers, paired with the perylenediimide (PDI) 3D “propeller acceptor” Ph(PDI)3. The PBDTTF-FTTE:Ph(PDI)3 devices exhibit a > 50 % power conversion efficiency (PCE, up to 9.1%) increase versus PBDTT-FTTE:Ph(PDI)3. This enhancement reflects structurally optimized phase separation due to templating effects, affording reduced energy loss, higher electron mobility, greater free charge lifetimes and yields, and lower bimolecular recombination, as quantified by UPS, AFM, TEM, GIWAXS, SCLC, light intensity dependence measurements, and fs/ns transient absorption (TA) spectroscopy. In PBDTTF-FTTE, the DFT-computed dipole orientations of the ground and excitonic states is nearly antiparallel, explaining the longer free charge lifetimes, minimized recombination, and lowered exciton binding energy. The PBDTTF-FTTE:Ph(PDI)3 performance enhancement vs. that of the fluorine-poor PBDTT-FTTE:Ph(PDI)3 analogue as well as the overall PSC performance exceeds that of the corresponding PC71BM- and ITIC-Th-based cells.
关键词： Perylenediimide,Energy loss,Fluorine tuning,Carrier dynamics,Morphology,Polymer solar cells
更新于2025-09-16 10:30:52
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The Crucial Role of Fluorine in Fully Alkylated Ladder Type Carbazole Based Non-fullerene Organic Solar Cells
摘要： Two fused ladder type non‐fullerene acceptors, DTCCIC and DTCCIC‐4F, based on an electron‐donating alkylated dithienocyclopentacarbazole core flanked by electron‐withdrawing non‐fluorinated or fluorinated 1,1‐dicyanomethylene‐3‐indanone (IC or IC‐4F), are prepared and utilized in organic solar cells (OSCs). The two new molecules reveal planar structures and strong aggregation behavior, and fluorination is shown to red shift the optical band gap and down shift energy levels. OSCs based on DTCCIC‐4F exhibit a power conversion efficiency of 12.6 %, much higher than that of DTCCIC based devices (6.2 %). Microstructural studies reveal that while both acceptors are highly crystalline, bulk heterojunction blends based on the non‐fluorinated DTCCIC result in overly coarse domains, while blends based on the fluorinated DTCCIC‐4F exhibit a more optimal nanoscale morphology. These results highlight the importance of end group fluorination in controlling molecular aggregation and miscibility.
关键词： fluorine effect,carbazole,fully alkylated side chains,organic solar cells,non‐fullerene acceptors
更新于2025-09-16 10:30:52
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Two-Dimensional Fluorine Distribution in a Heavily Distorted Perovskite Nickel Oxyfluoride Revealed by First-Principles Calculation
摘要： Most perovskite oxyfluorides synthesized to date have cubic structures, wherein fluorine atoms tend to reside at every oxygen site randomly. In this theoretical study, we show a two-dimensional fluorine arrangement in a perovskite nickel oxyfluoride (NdNiO2F) with a large orthorhombic distortion. The site selectivity in the perovskite lattice is due to the orthorhombicity, which stabilizes the two-dimensional cis configurations with shorter Ni?O and longer Ni?F bonds to minimize the electrostatic energy. The electronic structure of NdNiO2F is characterized by its large octahedral rotation and the higher electronegativity of fluorine than oxygen. We also observed how the anion arrangement was affected by the biaxial strain by modeling epitaxial strained thin film on substrate and found that the 2D cis structure remains the most stable. However, the orientation of the two-dimensional structure containing F depends on the magnitude of the biaxial strain. Our findings suggest that fluorine doping in orthorhombic perovskite oxides effectively yields oxyfluorides with anisotropic anion ordering.
关键词： electronic structure,orthorhombic distortion,perovskite oxyfluorides,two-dimensional fluorine arrangement,biaxial strain
更新于2025-09-12 10:27:22