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The bending strength of silicon nitride (Si3N4) plays a vital role in its application and is influenced by various process factors. Current experimental methods for investigating Si3N4 ceramics exhibiting low efficiency and high cost are incapable of systematically analysing the effect of process factors on the bending strength of Si3N4 ceramics and quantitatively predicting the optimum process parameters. In this study, machine learning (ML) approaches based on extreme gradient boosting (XGBoost) were applied to predict and analyse the bending strength of Si3N4 ceramics. Because the classification model of XGBoost is easily interpretable, the factors affecting the bending strength could be quantitatively evaluated. The current model can provide a suitable order of adding sintering additives to obtain excellent bending strength in Si3N4 ceramics. Although this study focuses on the bending strength of Si3N4 ceramics, the new approach reported herein is applicable for the in silico design and analysis of other ceramic materials.

We report a type of core@dotted-shell structured nanoprobe that incorporates water-soluble silica and water-interacted gadolinium oxide, endowed with excellent hydrophilicity and high magnetic reso...

The status of oxygen impurity in β-Si3N4 lattice and its impact on β-Si3N4 phonon spectrum were studied using the first principle calculation based on density functional theory. The dependence of in silico thermal conductivity of β-Si3N4 upon lattice oxygen was quantitatively addressed. This study also confirms that rare-earth La doping has a pinning effect on oxygen, which underlies, in mechanism, for the increase of thermal conductivity of β-Si3N4 ceramic by restraining oxygen diffusion inside β-Si3N4 lattice. The theoretical prediction above is consistent in trend with the reported experimental results. In addition, in silico modulus values of β-Si3N4 ceramic were also revealed declined with increasing oxygen impurity.

A framework for the software Unstructured Reaction-Diffusion Master Equation (URDME) was developed. A mitogenic paracrine signaling pathway was introduced phenomenologically to show how cells cooperate with one another. We modeled the emerging Allee effect using low seeding density culture (LSDC) assays to fit the model parameters. Finite time scaling (FTS) was found to be a useful tool for quantifying invasiveness in cancer populations. Through simulation, we analyzed the growth-migration dynamics of BT474 cancer cell populations in-vitro in a 2D percolation cluster and calculated the SPR (successful penetration rate). By analyzing the temporal trajectories of the SPR, we could determine the critical exponents of the critical SPR scaling relation. Moreover, the SPR transition point defined according to the FTS theory,Pc, is negatively correlated with the invasiveness of cancer cell populations. ThePcof the three virtual cancer populations distinctly designated by varying the parameter set of the same model are 0.3408, 0.3675, and 0.4454, respectively. Therefore, the FTS algorithm may be useful in determining invasiveness. Through the simplistic phenomenological paracrine model, inter-cell cooperation and mutual mitogenic boosting are enabled, causing the Allee effect to occur. Such a method could be applied to other circumstances as an example of the quantitatively falsifiable emerging theory.

We developed a framework based on the software Unstructured Reaction-Diffusion Master Equation (URDME) to address tumor cells' proliferation and migration in a heterogeneous space, herein a 2D percolation cluster. A mitogenic paracrine signaling pathway is utilized phenomenologically to reveal how cells cooperate with one another. We modeled the emerging Allee effect using low seeding density culture (LSDC) assays to fit the model parameters. A Finite time scaling (FTS) function has been formulated to quantitatively analyze invasiveness of a virtual Growth-Migration (GM) system in mimicking the cancer cell growth. Through such simulation, we analyzed the GM dynamics of virtual model in mimicking the growth of BT-474 cancer cell populations in vitro in a 2D percolation cluster and calculated the successful penetration rate (SPR). By analyzing the temporal trajectories of the SPR, we could determine the critical exponents of the critical SPR scaling relation. The SPR transition point ([Formula: see text]), which is a fundamentally different from a conventional percolation transition point, is found to be negatively correlated with the invasiveness of this cancer cell. The [Formula: see text] of the three variations of the virtual GM system distinctly designated by varying paracrine-regulated Allee (PAllee) model phenotypes is 0.3408, 0.3675, and 0.4454, respectively. FTS algorithm thereon may serve as an approach to quantify invasiveness of tumor cells. Through a phenomenological paracrine model, inter-cell cooperation and mutual mitogenic boosting are enabled to elicit the Allee effect in the GM systems. The rationale behind such computationally tunable virtual mechanism can be applied to other circumstances concerning emerging processes.

Wampee fruit is a popular fruit cultivar in South‐East Asia due to its high levels of nutrients and antioxidants; however, pericarp browning leads to a short storage life with great economic loss during years. The purpose of this work was to determine whether postharvest ethanol fumigation affected pericarp browning development of wampee fruit during 12 days of storage at 8 ± 0.5°C, and if so, how it is related to phenol metabolism and how it affects quality attributes and antioxidant systems during storage. After fruits were fumigated with 100, 300, 500, and 800 μl/L for 5 hr at 22 ± 0.5°C, ethanol significantly reduced the development of pericarp browning by increasing total phenolics (TP) content and decreasing the activity of polyphenol oxidase (PPO), especially in 500 μl/L ethanol treatment. Additionally, ethanol delayed the losses in fruit firmness (FF), soluble solid content (SSC), and titratable acidity (TA), retarded weight loss and accumulation of malondialdehyde (MDA) content and maintained relatively high contents of ascorbic acid (AsA), total flavonoids (TF), and total antioxidant capacity (TAC) and activities of superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD). In conclusion, results demonstrated that postharvest ethanol fumigation in wampee fruit has ability to reduce pericarp browning development by regulating phenol metabolism and enhancing antioxidant systems., Ethanol fumigation reduced the development of pericarp browning; ethanol fumigation delayed the losses in firmness, the degradation of TSS, TA, and VC of wampee fruit. Ethanol fumigation maintained high contents of AsA, TF, and TAC and activities of SOD, CAT, POD in wampee fruit.

Objectives The purpose of this study was to evaluate the effect of combined postharvest use of Bacillus siamensis strain and chlorogenic acid on quality maintenance and disease control in wax apple fruit. Materials and Methods Wax apple fruit were treated with Bacillus siamensis strain (N1), chlorogenic acid (CHA) and N1+CHA and preserved at 25 °C for 12 d. The appearance and quality parameters were evaluated, along with the disease index, content of total soluble solids (TSS), total acid (TA), vitamin C (Vc), total phenolic, and flavonoids during cold storage. Meanwhile, the activities of β-1,3-glucanase (GLU), phenylalanine ammonialyase (PAL), polyphenol oxidase (PPO), and peroxidase (POD) were determined. Furthermore, the transcriptome and the expression level of key defense enzyme genes were analyzed by RNA-seq and real-time quantitative reverse transcription polymerase chain reaction. Results N1+CHA treatment significantly lowered DI and delayed fruit quality deterioration by slowing TSS and TA loss and enhancing antioxidant capacity, including Vc, total phenolic, and flavonoids content. Meanwhile, the activities of GLU, PAL, PPO, and POD were dramatically increased by N1+CHA treatment. Additionally, N1+CHA treatment modulated several metabolic pathways, including those involved in plant–hormone signal transduction and plant–pathogen interaction. The expression levels of key defense enzyme genes were significantly upregulated in stored wax apple fruit by the N1+CHA treatment, which were well coincided with the transcriptome data. Conclusions The combined use of N1+CHA significantly prevents disease and maintains fruit quality of wax apple during storage. These findings indicate that it could serve as a promising biological technique for preserving wax apple fruit.

This study develops a multifunctional molecular optical nanoprobe (SiO2@Gd2O3: Yb3+/Er3+/Li+@Ce6/MC540) with a unique core-satellite form. The rare-earth doped nanodots with good crystallinity are uniformly embedded on the surface of a hydrophilic silica core, and the nanoprobe can emit near-infrared-IIb (NIR-IIb) luminescence for imaging as well as visible light that perfectly matches the absorption bands of two included photosensitizers under 980 nm irradiation. The optimal NIR-IIb emission and upconversion efficiency are attainable via regulating the doping ratios of Yb3+, Er3+ and Li+ ions. The relevant energy transfer mechanism was addressed theoretically that underpins rare-earth photoluminescence where energy back-transfer and cross relaxation processes play pivotal roles. The nanoprobe can achieve an excellent dual-drive photodynamic treatment performance, verified by singlet oxygen detections and live-dead cells imaging assays, with a synergistic effect. And a brightest NIR-IIb imaging was attained in tumoral site of mouse. The nanoprobe has a high potential to serve as a new type of optical theranostic agent for tumor.

Fusarium is an important plant pathogen and many cell wall-degrading enzymes (CWDEs) are produced in Fusarium-infected plant tissues. To investigate the role of CWDEs in the pathogenicity of pitaya pathogen, we isolated a Fusarium equiseti strain from the diseased pitaya fruit and the activities of CWDEs were determined. The higher polygalacturonase (PG) activity was confirmed both in vitro and vivo. Aiming at the PG gene, the CRISPR/Cas9 system of F. equiseti was constructed and optimized for the first time. Through the process of microhomology-mediated end joining, the flanking region containing 30 bp was used to mediate the homologous recombination of Cas9 double-strand breaks, and the PG gene knockout mutants were obtained by protoplast transformation. Through the phenotypic and pathogenicity experiments of the wild-type strain and mutant strain, the results showed that the colony growth rate and spore production of the strain without the PG gene decreased to some extent, and the lesion diameter and the degree of pericarp cell damage decreased, which showed that the CRISPR/Cas9 system could be used in F. equiseti and PG enzyme and can play a significant role in the interaction between F. equiseti and pitaya fruit.

Lanthanide fluorescence nanoprobe is versatile in multicolor cell imaging, although it still faces a great challenge in improving its luminescent efficiency. Herein, we validated the feasibility of lanthanide ions co-doped gadolinium phosphate nanocrystals serving as a safe, effective and color-tunable fluorescence probe for live cell imaging. Well-crystallized hexagonal phase GdPO4 nanoparticles with multi-morphologies such as nanowires, nanorods, tetragonal nanocubes and hexagonal nanoprisms were synthesized via a typical hydrothermal method. We have systematically investigated the synthesis of different morphologies of GdPO4 nanoparticles through adjusting their processing parameters. The nanoparticles can gain a bright color-tunable photoluminescence from red, orange, yellow to green region when the GdPO4 nanoparticles are co-doped with Eu3+ and Tb3+ ions. The Tb3+ doping significantly enhances the characteristic 4f → 4f transitions of Eu3+ owing to a specific cross-relaxation process from Tb3+ to Eu3+ ions; the mechanism underlying the cross relaxation was exposited in detail. Further biological experiments in vitro proved that the prepared nanoprisms could exhibit a favourable biocompatibility with negligible toxicity. The current investigation manifests a high potential of the nanoparticles applicable to fluorescence imaging probe for live cells.

Early diagnosis of diseases by contrast-enhanced magnetic resonance imaging (MRI) using iron oxide superparamagnetic nanoparticles (IOSNPs) has been extensively investigated due to the good biocompatibility of modified IOSNPs. However, the low magnetic sensitivity of IOSNPs still inflicts a certain limitation on their further application. In this study, we employed first-principles calculations based on spin-polarized density functional theory (SDFT) to find the optimal dysprosium-doped scheme for improving the magnetic sensitivity of IOSNPs. Elicited from the optimal doping scheme, we synthesized a sort of ultrasmall γ-iron oxide superparamagnetic nanoparticle by a special phase transfer-coprecipitation method. The appropriately Dy-doped γ-IOSNPs coated with short-chain polyethylene glycol are small in hydrodynamic size and highly dispersed with effectively improved superparamagnetism for enhancing T2-weighted MRI relaxivity, which is well consistent with the SDFT prediction. The measured spin-spin relaxivity r2 is 123.2 s-1 mM-1, nearly double that of the pure γ-IOSNPs (67.8 s-1 mM-1) and substantially surpassing that of both clinically-approved T2 contrast agents Feridex and Resivist. The low dysprosium doping does not induce notable nanotoxicity for IOSNPs, but contributes sufficiently to their high relaxation performance instead, which endows the Dy-doped γ-IOSNPs with high potential as a better T2-weighted MRI contrast medium. Both the method and the nanomagnets reported in this study are expected to promote studies on designing and preparing high-performance MRI contrast agents as well as computational materials.

Background Accurately predicting the risk of death, recurrence, and metastasis of patients with nasopharyngeal carcinoma (NPC) is potentially important for personalized diagnosis and treatment. Survival outcomes of patients vary greatly in distinct stages of NPC. Prognostic models of stratified patients may aid in prognostication. Purpose To explore the prognostic performance of MRI-based radiomics signatures in stratified patients with NPC. Study type Retrospective. Population Seven hundred and seventy-eight patients with NPC (T1-2 stage: 298, T3-4 stage: 480; training cohort: 525, validation cohort: 253). Field strength/sequence Fast-spin echo (FSE) axial T1-weighted images, FSE axial T2-weighted images, contrast-enhanced FSE axial T1-weighted images at 1.5 T or 3.0 T. Assessment Radiomics signatures, clinical nomograms, and radiomics nomograms combining the radiomic score (Radscore) and clinical factors for predicting progression-free survival (PFS) were constructed on T1-2 stage patient cohort (A), T3-4 stage patient cohort (B), and the entire dataset (C). Statistical tests Least absolute shrinkage and selection operator (LASSO) method was applied for radiomics modeling. Harrell's concordance indices (C-index) were employed to evaluate the predictive power of each model. Results Among 4,410 MRI-extracted features, we selected 16, 16, and 14 radiomics features most relevant to PFS for Models A, B, and C, respectively. Only 0, 1, and 4 features were found overlapped between models A/B, A/C, and B/C, respectively. Radiomics signatures constructed on T1-2 stage and T3-4 stage patients yielded C-indices of 0.820 (95% confidence interval [CI]: 0.763-0.877) and 0.726 (0.687-0.765), respectively, which were larger than those on the entire validation cohort (0.675 [0.637-0.713]). Radiomics nomograms combining Radscore and clinical factors achieved significantly better performance than clinical nomograms (P Data conclusion The selected radiomics features and prognostic performance of radiomics signatures differed per the type of NPC patients incorporated into the models. Radiomics models based on pre-stratified tumor stages had better prognostic performance than those on unstratified dataset. Level of evidence 4 Technical Efficacy Stage: 5.

High-sensitivity optical imaging can be achieved through improving upconversion photoluminescence (UCPL) efficiency of localized surface plasmon resonance (LSPR)-enhanced excitation and emission. Herein, we report a type of UCPL nanoprobe, Au nanospheres assemblage@Gd2O3:Yb3+/Ln3+ (Ln = Er, Ho, Tm), which exhibits emission enhancements from 46- to 96-fold as compared with its Au-free counterparts. The aggregation and interaction among Au nanospheres embedded inside the nanoprobe brings about three characteristic LSPR peaks in visible and near-infrared regions according to simulated and experimental absorption spectra, resulting in both excitation and emission fields simultaneously intensified all through the entire nanoprobe. We addressed a characteristic wavelength dependence on emission amplifications, which could be elucidated by a LSPR-enhanced UCPL mechanism and relevant rate equations that we addressed. The nanoprobe was verified to have a superior capability for optical bio-imaging with a negligible toxicity in vitro and in vivo. This study realizes a synchronous double-field-enhanced upconversion of optical nanoprobe in situ, and may gain an insight into its mechanism underlying for LSPR-induced UCPL enhancement.

The purpose of this study was to evaluate the control effect of Bacillus atrophaeus TE7 on Cladosporium cladosporioides of mango fruit and how it effects quality attributes during 'Tainong' mango fruit storage. The results showed that strain TE7 had inhibition ability with the biocontrol efficacy of 85.56%. Furthermore, strain TE7 could produce lipopeptide substance, iturin A, and surfactants, which inhibited the growth and development of C. cladosporioides. Moreover, strain TE7 had the ability of improving the activities of defense response-related enzyme in mangoes. The changes of peel color, flesh firmness, contents of total soluble solids (TSS), titratable acid (TA), and ascorbic acid (Vc) were significantly delayed by strain TE7. The results demonstrated that B. atrophaeus TE7 could be applied as a biocontrol agent for the pathogen C. cladosporioides of mango fruit.

Rapid pericarp browning is the leading factor for quality deterioration and marketing decline of litchi fruit. In the present study, litchi fruit was treated with phenolic compounds, proanthocyanidin, p-coumalic acid, chlorogenic acid, apple polyphenol, and tea polyphenol, before being stored at 20°C for 10 d. Phenolic compound treatment delayed pericarp browning and weight loss, reduced respiration rate, and maintained high total acid levels and vitamin C content in litchi fruit. Subsequently, the key antioxidant characteristics were determined to evaluate the effects of phenolic compounds on the antioxidant system during pericarp browning. The phenolic compound-treated fruit exhibited higher levels of antioxidant enzymes, anthocyanins, total phenols, flavonoids, and antioxidant capacity, as well as a lower superoxide radical production rate and polyphenol oxidase and peroxide activities during whole-fruit storage than the control. Of the five treatments, proanthocyanidin application produced the most significant effects; therefore, this may be the best method for inducing antioxidant system-related factors, enhancing antioxidant capacity, and delaying pericarp browning in litchi.

We report the magneto-electric behavior of a dual-modality biomedical nanoprobe, a ternary nanosystem consisting of gold and gadolinia clusters and water molecules, with the effect of both nanoclusters on the structural and electronic properties of water. The hydrogen-oxygen bond lengths and angles as well as electronic charges of water molecules surrounding both nanoclusters were calculated using Hubbard U corrected density functional theory aided by molecular dynamics approach. The calculations reveal existence of a magneto-electric interaction between gold and gadolinium oxide nanoclusters, which influences the physical properties of surrounding water remarkably. A broader (narrower) distribution of H O bond lengths (H O H bond angles) was observed at the presence of either gold or gadolinia nanoclusters. The presence of Gd6O9 cluster leads to the larger charges of neighbour oxygen atoms. The distribution of oxygen atom charges becomes border when both Gd6O9 and A u 13 clusters coexist. Ab initio calculation provides a feasible approach to explore the most essential interactions among functional components of a multimodal nanoprobe applied in aqueous environment.

Uniform and well-crystallized tetragonal NaGd(MoO 4 ) 2 nanocrystals with the morphology of nanocubes were synthesized via a modified hydrothermal synthesis method with oleic acid as complexing agent. The as-synthesized NaGd(MoO 4 ) 2 nanocubes were characterized by means of powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy and selected area electron diffraction respectively. The side-length of the NaGd(MoO 4 ) 2 nanocubes is about 100–150 nm. The SAED pattern indicates highly crystalline nature of the NaGd(MoO 4 ) 2 nanocubes. The effect of Na 2 MoO 4 contents on the formation of NaGd(MoO 4 ) 2 nanocrystals is investigated. A possible growth mechanism of NaGd(MoO 4 ) 2 nanocubes is deduced based on time-dependent morphology evolution and XRD analysis. Down-shifting/upconversion photoluminescence properties of NaGd(MoO 4 ) 2 : Eu 3+ , Tb 3+ and Yb 3+ /Er 3+ nanocubes are investigated in detail. Furthermore, the energy transfer mechanism for upconversion luminescence in NaGd(MoO 4 ) 2 : Yb 3+ /Er 3+ nanocubes is investigated on the basis of energy level scheme and the excitation power dependence of upconversion luminescence intensities.

We report the hyperfine couplings and chemical shifts of water protons in a typical NMR-photonic dual-modality nanoprobe that consists of gadolinium oxide and gold nanoclusters surrounded by water molecules, which have been addressed through density functional theory (DFT). The DFT calculation of the ternary system provide a feasible approach not only to explore the intriguing interactions among functional components of a multimodal nanoprobe applied in aqueous environment, but also to interpret the underlying mechanism for enhancement of modality that is too complicated to be addressed by a phenomenological approach of the conventional NMR theory.

We propose a novel and efficient F− anion doping strategy for enhancing upconversion luminescence in upconversion nanophosphors. NaGd(MoO4)2:Yb3+/Er3+ nanophosphors doped with different F− contents are synthesized hydrothermally. Rietveld refinement results obtained from X-ray diffraction data indicate that the Gd–O bond length decreases and the O–Gd–O bond angle varies with increasing F− content, resulting in augmented local crystal field strength and distorted local site symmetry of the dopant lanthanide sites. Judd–Ofelt analysis suggests that the calculated radiative quantum efficiency of the 4S3/2 level and the radiative branching ratio of 4S3/2 → 4I15/2 transition in F−-doped NaGd(MoO4)2:Yb3+/Er3+ nanophosphors are much greater than those in F− anion-free samples. It is inferred that F− anion doping helps to reduce the nonradiative transition probabilities based on the luminescence dynamics. Rietveld refinement results and Judd–Ofelt analysis confirm jointly that doping of interstitial F− anions could enhance local crystal field strength with odd parity and modify site symmetry of the lanthanide activator ions, leading to enhanced radiative transitions and inhibited nonradiative transitions. A maximum of 17-fold enhancement of total emission intensity is found in NaGd(MoO4)2:Yb3+/Er3+/F− nanophosphors compared with F− anion-free counterparts. The proposed F− anion doping strategy provides an alternative approach for enhancing upconversion luminescence efficiency and could be extended to other inorganic upconversion nanomaterials.

The development of upconversion nanoparticles (UCNs) for theranostics application is a new strategy toward the accurate diagnosis and efficient treatment of cancer. Here, magnetic and fluorescent lanthanide-doped gadolinium oxide (Gd2O3) UCNs with bright upconversion luminescence (UCL) and high longitudinal relaxivity (r1) are used for simultaneous magnetic resonance imaging (MRI)/UCL dual-modal imaging and photodynamic therapy (PDT). In vitro and in vivo MRI studies show that these products can serve as good MRI contrast agents. The bright upconversion luminescence of the products allows their use as fluorescence nanoprobes for live cells imaging. We also utilized the luminescence-emission capability of the UCNs for the activation of a photosensitizer to achieve significant PDT results. To the best of our knowledge, this study is the first use of lanthanide-doped Gd2O3 UCNs in a theranostics application. This investigation provides a useful platform for the development of Gd2O3-based UCNs for clinical diagnosis, treatment, and imaging-guided therapy of cancer.

Uniform and well-crystallized NaGd(MoO4)2: Yb3+/Er3+ microcrystals with tetragonal plate morphology were synthesized by a facile hydrothermal method. The structure and phase purity of the samples were identified by powder XRD analysis. The steady-state and transient luminescence spectra were measured and analyzed. Under 980 nm excitation, intense green luminescence at 531 and 553 nm, and red luminescence at 657 and 670 nm were observed. The optimum doping concentrations for Yb3+ and Er3+ are determined to be 20% and 1% in NaGd(MoO4)2 tetragonal plate microcrystals. With increasing Yb3+ doping concentrations, the total integral emission intensities increase first and then decrease. The red/green intensity ratio of NaGd(MoO4)2: Yb3+/Er3+ microcrystals increases from 0.4 to 1.0 with the increase in Yb3+ concentrations. Based on the energy level diagram, the energy-transfer mechanisms are investigated in detail according to the double logarithmic plot of upconversion intensities versus pump powers. The energy-transfer mechanisms for green and red upconversion luminescence are ascribed to two-photon processes at lower Yb3+ concentrations, and involve high-Yb3+-induced one-photon processes at higher Yb3+ concentrations. For the red upconversion luminescence, energy back-transfer process, that is, 4S3/2 (Er3+) + 2F7/2 (Yb3+) → 4I13/2 (Er3+) + 2F5/2 (Yb3+), is dominant at higher Yb3+ concentrations. Theoretical model of the energy-transfer mechanisms based on rate equations is established, which agrees well with the experimental results.

Herein, hollow-structured Gd2O3:RE3+/Yb3+ (RE = Er, Ho, Tm) nanoparticles (NPs) were prepared via a urea-based chemical coprecipitation method followed by subsequent calcination and etching. Under 980 nm near-infrared (NIR) irradiation, upconversion (UC) emission gains the highest intensity of red, green and blue peaks for Gd2O3:Er3+/Yb3+, Gd2O3:Ho3+/Yb3+ and Gd2O3:Tm3+/Yb3+ NPs respectively. The corresponding fluorescence in-cell images exhibit bright visible light. The continuous color-tunable UC emission of each spectrum was investigated by increasing the concentration of the sensitizer Yb3+ ions from 0 to 20 mol% with the most intense red, green and blue emission achieved. The structure, morphology, components and magnetic property of Gd2O3:Ho3+/Yb3+ NPs were investigated intensively. The results show that the NPs possess a distinctly hollow structure and uniform spherical shape, and are well-crystallized and highly monodispersed with a mean diameter of 118 nm. Due to the designed hollow structure which is of benefit to water contact of a large number of Gd3+ on the surface, the measured T1 relaxivity of the NPs is nearly 5 times larger than the relaxivity of the commercial gadolinium diethylenetriaminepentaacetate (Gd-DTPA). The relaxation enhancement in the hollow-structured Gd2O3:RE3+/Yb3+ (RE = Er, Ho, Tm) NPs is addressed in the framework of Solomon–Bloembergen–Morgan theory. The biocompatibility studies in 293 and HeLa cells indicate that the hollow NPs have no observable cytotoxicity at a concentration up to 200 μg ml−1. All these results demonstrate that the hollow-structured nanocomposite has the potential to be developed into a safe and highly efficient magnetic resonance and fluorescence nanoprobe for in-cell molecular imaging of cancer.

The longitudinal surface plasmon resonance of light-irradiated gold nanorods (Au NRs) is generated to enhance the local electric fields of Au NR-based nano-dumbbells (NDs), tailored specifically by coating mesoporous silica at two poles of Au NRs and embedding photosensitizer indocyanine green (ICG) into the mesopores. The assembled NDs possess a superior uniformity and water dispersity with a strong plasmonic absorption around 800 nm. Time-domain finite-difference calculations indicate that the enhanced local electric field of NDs is predominantly distributed in the dumbbells at two poles of Au NRs, which improves the photonic performance of ICG significantly. Illuminated by an 800 nm laser, the fabricated NDs demonstrate an enhanced combination of photothermal and photodynamic effects in comparison to either Au NRs or ICG alone. Synergistic damaging of photothermal and photodynamic combination to nasopharyngeal carcinoma cells has been corroborated experimentally, thus causing substantial cell death under a lower incident near-infrared laser power. This study concludes that the plasmonic NDs combined synergistically with efficient photothermal and photodynamic effects are highly promising in cancer therapy.

Purpose To establish effective prognostic nomograms using clinical features and detailed magnetic resonance imaging (MRI) findings for primary tumor and regional lymph nodes after intensity-modulated radiotherapy (IMRT) in patients with nasopharyngeal carcinoma. Method The nomogram for overall survival (OS) was based on a retrospective study of 595 patients who underwent IMRT at Sun Yat-sen University Cancer Center from 2010 to 2012. The predictive accuracy and discriminative ability of our nomogram models were determined by concordance index and calibration curve, and were compared with the nomogram models combining clinical features with tumor-node-metastasis (TNM) classification. The results were validated using bootstrap resampling and a cohort study of 241 patients. The same data cohort was used to predict the progress-free survival (PFS) of nasopharyngeal carcinoma with 3:1 training cohort (N = 558) and validation cohort (N = 278). Results The following factors were assembled into our prognostic survival nomogram models: Age, Epstein–Barr virus DNA copy number before treatment (EBV_DNA_CN), tensor veli palatini (TVP) involvement, musculus pterygoideus lateralis (MPL) involvement, prestyloid space (PS) involvement, prevertebral space (PVS) involvement, base of sphenoid bone (BOSB) involvement, paranasal sinus (PNS) involvement, the laterality of Ⅱ (Ⅱ_laterality), the laterality of retropharyngeal lymph node (RPLN_laterality), nodal grouping (NG), extranodal neoplastic spread (ENS), contrast-enhancing rim (CER) and Nodal_number. The calibration curves showed good agreement between nomogram-predicted and actual survival. Our nomogram models for OS and PFS, provided better results than the nomogram models combining clinical features with TNM classification. Results were further confirmed in the validation set. Conclusion Detailed MRI findings of primary tumor and regional lymph nodes can improve the performance of prognostic nomograms for patients with nasopharyngeal carcinoma.

Gadolinium oxide-based core-shelled nanoparticles have recently emerged as novel magnetic resonance imaging contrast agents for high relaxivity and tumor targeting. However, their relaxivity enhancement mechanism has not yet been clearly understood. We prepared highly dispersible and uniform core-shell structured nanoparticles by encapsulating silica spheres (90 nm in diameter) with gadolinium oxide shells of different thicknesses (from 1.5 nm to 20 nm), and proved experimentally that the shell thickness has an inverse effect on relaxivity. The core-shelled nanoparticles are of a larger relaxivity than the commercial contrast agent Gd-DTPA, with an enhancement from 1.8 to 7.3 times. Based on the Solomon-Bloembergen-Morgan theory which is usually adopted for interpreting the relaxation changes of water protons in Gd3+ chelates, we introduced a shielding ansatz of nanoshells and derived a concise formula specifically to correlate the relaxivity of this sort of core-shelled nanoparticles with the shell thickness directly. The formula calculation is well consistent with the experimental results, and the formula can be generally applied to evaluate the relaxation enhancement underlying the high relaxivity of any core-shelled nanoparticle. Furthermore, the core-shelled nanoparticles possess a negligible nanotoxicity according to the in vitro cytotoxicity and in vivo histopathology and hematology assays. The enhanced signals of in vivo tumor-targeted magnetic resonance imaging indicate that the ultrathin gadolinium oxide nanoshells may function as a potential candidate for advanced positive contrast agents in further clinical applications.