Symmetry-Triggered Tunable Phosphorescence Lifetime of Graphene Quantum Dots in a Solid State.

Studying the phosphorescent mechanisms of carbon nanostructures synthesized by the "bottom-up" approach is key to understanding the structure modulation and the interfacial properties of carbon nanostructures. In this work, the relationships among symmetry of precursors in the "bottom-up" synthesis, structures of products, and phosphorescence lifetimes of graphene quantum dots (GQDs) are studied. The symmetry matching of precursors in the formation of a D6h graphene-like framework is considered the key factor in controlling the separability of sp2 domains in GQDs. As the separability of sp2 domains in GQDs increases, the phosphorescence lifetimes (14.8-125.5 ms) of GQDs in the solid state can be tuned. Machine learning is used to define the degree of disorder (S) of the GQD structure, which quantitatively describes the different space groups of precursors. The negative correlation between S and the oscillator strength of GQDs is uncovered. Therefore, S can be recognized as reflective of oscillator strength in the GQD structure. Finally, based on the correlations found between the structures and phosphorescence lifetimes of GQDs, GQDs with an ultralong phosphorescence lifetime (28.5 s) are obtained. Moreover, GQDs with visible phosphorescence emission (435-618 nm) are synthesized.

Brain magnetic resonance imaging as predictors in pediatric anti-N-methyl-D-aspartate receptor encephalitis.

OBJECTIVE: To investigate the associations between brain magnetic resonance imaging (MRI) changes and clinical profiles in children with anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis. METHODS: Clinical data and brain MRI results of children diagnosed with anti-NMDAR encephalitis in Guangzhou Women and Children's Medical Center from October 2014 to June 2022 were retrospectively studied. RESULTS: A total of 143 children (Male: female 54:89) were enrolled, with a mean onset age of 6.8 years (6.8 ± 3.1). 40.6 % (58/143) of patients had abnormal initial brain MRI. Lesions in temporal lobe (34.5 %, 20/58) and frontal lobe (25.9 %, 15/58) were relatively common. Children with abnormal initial brain MRI were prone to have fever (P = 0.023), dystonia (P = 0.037), positive MOG antibodies (P = 0.015), higher cerebrospinal fluid (CSF) white blood cell count (WBC) (P = 0.019) and to receive rituximab treatment (P = 0.037). There were no significant differences in modified Rankin Scale (mRS) scores before immunotherapy, after immunotherapy and at last follow-up between the normal initial brain MRI group and abnormal group. No initial brain MRI changes were found to be associated with relapses. Brain MRI was reviewed in 72 patients at last follow-up with a median follow-up time of 25.5 months and 48.6 % (35/72) of patients had abnormal brain MRI. The mRS score of the group with normal brain MRI at last follow-up was significantly lower than that of the abnormal group. CONCLUSIONS: About 40.0 % of children with anti-NMDAR encephalitis had abnormal initial brain MRI. Initial brain MRI was associated with certain clinical profiles, but not with relapse and prognosis. Around half of patients had abnormal brain MRI at last follow-up and were prone to have higher mRS score.

Fabrication of Carbon-Based Quantum Dots via a "Bottom-Up" Approach: Topology, Chirality, and Free Radical Processes in "Building Blocks".

The discovery of carbon-based quantum dots (CQDs) has allowed opportunities for fluorescence bioimaging, tumor diagnosis and treatment, and photo-/electro-catalysis. Nevertheless, in the existing reviews related to the "bottom-up" approaches, attention is mainly paid to the applications of CQDs but not the formation mechanism of CQDs, which mainly derived from the high complexities during the synthesis of CQDs. Among the various synthetic methods, using small molecules as "building blocks", the development of a "bottom-up" approach has promoted the structural design, modulation of the photoluminescence properties, and control of the interfacial properties of CQDs. On the other hand, many works have demonstrated the "building blocks"-dependent properties of CQDs. In this review, from one of the most important variables, the relationships among intrinsic properties of "building blocks" and photoluminescence properties of CQDs are summarized. The topology, chirality, and free radical process are selected as descriptors for the intrinsic properties of "building blocks". This review focuses on the induction and summary of recent research results from the "bottom-up" process. Moreover, several empirical rules pertaining thereto are also proposed.

On the measurement of remote sensing reflectance by a traditional above-water approach in small water bodies.

Small water bodies are an important part of the Earth's freshwater system, protecting biodiversity and providing ecosystem services. Because of various surrounding features, it is unknown to what extent we can obtain accurate remote-sensing reflectance (Rrs) of such an environment by the conventional above-water approach (AWA). In this study, we used both AWA and the skylight-blocked approach (SBA) side-by-side to measure Rrs in a typical small water body. It was found that the variation of Rrs in the UV-blue domain from AWA is around 50% and is inconsistent with the variation of the total absorption coefficient (at) obtained from water samples; on the contrary, the variation of Rrs obtained from SBA is highly consistent, with a coefficient of variation under ∼5%. These results highlight the large uncertainties in the measured Rrs from AWA due to the complexity of such an environment and further echo the robustness of SBA to measure Rrs in the field, even in such challenge environments.

Synergistic Effect of Oxygen- and Nitrogen-Containing Groups in Graphene Quantum Dots: Red Emitted Dual-Mode Magnetic Resonance Imaging Contrast Agents with High Relaxivity.

Contrast agents (CAs) in magnetic resonance imaging generally involve the dissociative Gd3+. Because of the limited ligancy of Gd3+, the balance between Gd3+ coordination stability (reducing the concentration of dissociative Gd3+) and increases in the number of coordination water molecules (enhancing the relaxivity) becomes crucial. Herein, the key factor of the synergistic effect between the O- and N-containing groups of graphene quantum dots for the structural design of CAs with both high relaxivity and low toxicity was obtained. The nitrogen-doped graphene quantum dots (NGQDs) with an O/N ratio of 0.4 were selected to construct high-relaxivity magnetic resonance imaging (MRI)-fluorescence dual-mode CAs. The coordination stability of Gd3+ can be increased through the synergetic coordination of O- and N-containing groups. The synergetic coordination of O- and N-containing groups can result in the short residency time of the water ligand and achieve high relaxivity. The resulting CAs (called NGQDs-Gd) exhibit a high relaxivity of 32.04 mM-1 s-1 at 114 µT. Meanwhile, the NGQDs-Gd also emit red fluorescence (614 nm), which can enable the MRI-fluorescence dual-mode imaging as the CAs. Moreover, the bio-toxicity and tumor-targeting behavior of NGQDs-Gd were also evaluated, and NGQDs-Gd show potential in MRI-fluorescence imaging in vivo.

Identification of proteins related with pemetrexed resistance by iTRAQ and PRM-based comparative proteomic analysis and exploration of IGF2BP2 and FOLR1 functions in non-small cell lung cancer cells.

Pemetrexed (PEM), a multi-target folate antagonist, has been extensively used for the treatment of non-small cell lung cancer (NSCLC). However, the therapeutic efficacy of PEM is limited by tumor resistance. In this project, iTRAQ and parallel reaction monitoring (PRM)-based LC-MS/MS comparative proteomic analysis was performed to identify protein determinants of PEM resistance in A549/PEM cells versus A549 parental cells. A total of 567 differentially expressed proteins (DEPs) were identified by iTRAQ analysis. The function and classification of DEPs were analyzed through GO and KEGG Pathway databases. Moreover, PRM analysis further validated the expression changes of 14 DEPs identified by iTRAQ analysis. Moreover, insulin-like growth factor (IGF) 2 mRNA-binding protein 2 (IGF2BP2) or folate receptor alpha (FOLR1) knockdown weakened PEM resistance, reduced cell viability and promoted cell apoptosis in A549/PEM cells. IGF2BP2 depletion inhibited cell migration, invasion and epithelial-mesenchymal transition (EMT), while FOLR1 loss had no much effect on cell migration, invasion and EMT in A549/PEM cells. Our study can provide a deep insight into molecular mechanisms of PEM resistance in NSCLC and contribute to the development of more effective therapeutic schedules. SIGNIFICANCE: Our study can provide deeper insight into molecular mechanisms of PEM resistance in NSCLC and contribute to the development of more effective therapeutic schedules.

The PVT1/miR-216b/Beclin-1 regulates cisplatin sensitivity of NSCLC cells via modulating autophagy and apoptosis.

PURPOSE: The efficacy of cisplatin-based chemotherapy remains an open question for chemo-resistance in non-small cell lung cancer (NSCLC). This study aimed to explore the role and mechanism of long noncoding RNA plasmacytoma variant translocation 1 (PVT1) in cisplatin sensitivity of NSCLC. METHODS: Paired tumor and adjacent tissues were collected from forty patients with NSCLC. The clinical value of PVT1 was investigated according to clinicopathological parameters of patients. Cisplatin-sensitive or -resistant cells (A549 or A549/DDP) were used for in vitro experiments. Cell viability, apoptosis, autophagy and animal experiments were conducted to investigate cisplatin sensitivity. The expressions of PVT1, microRNA-216b (miR-216b) and apoptosis- or autophagy-related proteins were measured by quantitative reverse transcription polymerase chain reaction (qRT-PCR) or western blot assay, respectively. Luciferase reporter assay and RNA immunoprecipitation (RIP) assay were conducted to probe the interaction between miR-216b and PVT1 or Beclin-1. RESULTS: PVT1 was highly expressed and associated with poor prognosis of NSCLC patients (*P < 0.05). PVT1 knockdown enhanced cisplatin-induced viability inhibition and apoptosis induction in A549/DDP cells, but addition of PVT1 caused an opposite effect in A549 cells (*P < 0.05, #P < 0.05). Moreover, accumulation of PVT1 facilitated autophagy of NSCLC cells and tumor growth in vivo (*P < 0.05, #P < 0.05). In addition, miR-216b interacted with PVT1 or Beclin-1. Beclin-1 reversed miR-216b-mediated effect on autophagy and apoptosis of NSCLC cells (*P < 0.05,#P < 0.05). Besides, Beclin-1 protein expression was regulated by PVT1 and miR-216b (*P < 0.05, #P < 0.05). CONCLUSIONS: PVT1 may function as a competing endogenous RNA for miR-216b to inhibit cisplatin sensitivity of NSCLC through regulating apoptosis and autophagy via miR-216b/Beclin-1 pathway, providing a novel target for improving chemo-therapy efficacy of NSCLC.

GSK3ß mediates the carcinogenic effect of HPV16 in cervical cancer.

Cervical cancer is one of the most prevalent and fatal cancers among women and infection of the human papillomavirus (HPV) is the most important risk factor. This study investigated how HPV16 regulated GSK3ß expression and function to promote cervical cancers. The expression of GSK3ß was analyzed by quantitative PCR and western blot. The proliferation, invasion, and clonogenic survival of cells with different E6/E7 levels were measured by MTT, transwell invasion assays, and soft agar colony-forming assays, respectively. The levels of GSK3ß were correlated with the copy numbers and expression levels of HPV16 E6/E7 genes. HPV16 E6/E7 genes regulated GSK3ß transcription through an element located in the promoter 85 and 250 base pairs upstream of the transcription start site. The abilities of cell proliferation, invasion, and clonogenic survival were increased in C33A cells by ectopic HPV16 E6/E7 and decreased in CaSki cells by knocking down HPV16 E6/E7 levels. Meanwhile, LiCl increased GSK3ß transcript levels and the proliferation of CaSki cells in a HPV16-dependent manner. These data indicated that GSK3ß may participated in HPV16 mediated deregulation of wnt/ß-catenin and other signaling pathways promoting the progression and invasion of cervical cancers.

Spectral studies of multi-branched fluorescence dyes based on triphenylpyridine core.

A series of novel triphenylpyridine-containing triphenylamine derivatives have been carefully designed and prepared in good yields using the stepwise route reactions. The relationship of photoluminescence property and structure of compounds 9-13 was systematically investigated via UV-vis, fluorescence, thermogravimetric and electrochemical analyzer. The highest occupied molecular orbital and the lowest unoccupied molecular orbital distributions of compounds 9-13 were calculated by density functional theory method. The high fluorescence quantum yields, desirable the highest occupied molecular orbital levels and high thermal stability of compounds 9-13 indicate that the linkage of triphenylpyridine and triphenylamine is an efficient means to enhance hole-transporting ability and fluorescent quantum yield.

Three-dimensional shape measurement using improved binary spatio-temporal encoded illumination and voting algorithm.

Some regions of objects will be measured incorrectly or cannot be measured in optical three-dimensional (3D) measurement system based on coded structured light, due to occlusion, shadow, transfer function of measurement system, and noise. To obtain 3D data as much as possible and as correctly as possible, we proposed a method using improved binary spatio-temporal encoded illumination and voting algorithm. Firstly, the binary spatio-temporal encoded (BSE) pattern is improved with a redundancy encoding method. One code is assigned to two adjacent sections and distinguished with their temporal coordinates. The redundancy encoding method provides more cues for code correcting and retrieving. Secondly, symbols are estimated according to four coding cues--code redundancy, continuity of stripes, intensity variation in temporal direction, and neighbor symbols in sequence. Finally, a voting algorithm is adopted to obtain final symbols. A plaster model of a human head was measured to validate the method. The experimental results reveal that more valid points can be obtained and the reliability of the decoding results is improved.

Polarographic behaviors of diclofenac sodium in the presence of dissolved oxygen and its analytical application.

The polarographic response characteristics of diclofenac sodium were investigated in 0.25 M HAc-NaAc (pH 5.0) supporting electrolyte in the absence and the presence of dissolved oxygen. The results demonstrate that the reduction peak at ca. -1.10 V is a catalytic hydrogen wave after deaeration, and the reduction peak in the presence of dissolved oxygen is a so-called parallel catalytic hydrogen wave. Based on the parallel catalytic hydrogen wave, a novel method has been proposed for the determination of diclofenac sodium by single-sweep polarography. The calibration curve is linear in the range 1.2 x 10(-7)-2.6 x 10(-6)M and the detection limit is 6.0 x 10(-8)M. The proposed method is applied to the direct determination of diclofenac sodium in tablet forms and biological samples.