Pyrene-Based Nonwoven Fabric with Tunable Fluorescence Properties by Employing the Aggregation-Caused Quenching Effect

Conventional aromatic compounds tend to exhibit the formation of sandwich-shaped excimers and exciplexes between their excited and ground states at high concentrations or in their aggregated states, causing their fluorescence to weaken or disappear due to the aggregation-caused quenching (ACQ) effect. This limits their applications in concentrated solutions or solid materials. Herein, for the first time, ACQ-based pyrene (Py) units are covalently connected to the surface of polyethylene/polypropylene nonwoven fabric (PE/PP NWF) via electron beam preradiation-induced graft polymerization followed by chemical modification. The matrix can be considered a solid solvent and Py units as a solid solute, such that the amount of Py units can be controlled by varying the reaction time. The obtained fluorescent fabric not only exhibits remarkable fluorescence properties with high fluorescence intensity, high quantum yield (>90%), and excellent fluorescence stability after laundering or in harsh chemical environments, but the fluorescence color and intensity, quantum yield, and lifetime can also be regulated by employing the ACQ effect. Additionally, the as-prepared fluorescent fabric can effectively distinguish common monocyclic aromatic hydrocarbons via a simple fluorescence response test.

TFF3 mediates the NF-κB/COX2 pathway to regulate PMN-MDSCs activation and protect against necrotizing enterocolitis

Intestinal trefoil factor 3 (TFF3) plays an important role in repairing the intestinal mucosa. However, the detailed mechanism regarding immune regulation by TFF3 is not well defined. Here, we reported that treatment of mouse BM cells and human peripheral blood mononuclear cells from healthy volunteers with TFF3 activated polymorphnuclear myeloid-derived suppressor cells (PMN-MDSCs) in vitro. We also found that prostaglandin E2 is a major TFF3-mediated MDSC target, and that NF-κB/COX2 signaling was involved in this process. Moreover, TFF3 treatment or transfer of TFF3-derived PMN-MDSCs (TFF3-MDSCs) to experimental necrotizing enterocolitis (NEC) mice caused PMN-MDSC accumulation in the lamina propria (LP), which was associated with decreased intestinal inflammation, permeability, bacterial loading, and prolonged survival. Interestingly, no NEC severity remission was observed in Rag1 KO mice that were given TFF3-MDSCs, but coinjection with CD4⁺ T cells significantly relieved NEC inflammation. Overall, TFF3 mediates the NF-κB/COX2 pathway to regulate PMN-MDSC activation and attenuates NEC in a T-cell-dependent manner, which suggests a novel mechanism in preventing NEC occurrence.

A Greener Amidoximation Process for Fabrication of Popular Uranium Complexing Fiber Using Water as the Single Solvent

A mixed water-organic solvent used for amidoximation increased the production cost of an amidoxime-based polymer sorbent and was not environmentally friendly as well. In this work, the amidoximation of an ultrahigh molecular weight polyethylene fiber co-grafted with acrylonitrile and methacrylic acid was carried out in aqueous solution without the use of an organic solvent. The effects of amidoximation parameters including NH₂OH concentration, temperature, time, and various solvents on the uranium adsorption performances in both uranium-spiked brine and simulated seawater were investigated. Results indicated that the optimal amidoximation parameters were 5% (w/v) NH₂OH, 80 °C, and 24 h. The uranium adsorption capacities of the sorbents amidoximated in aqueous solution were comparable with those of sorbents amidoximated in the various mixed water-organic solvents. Moreover, in comparison with both acidic (pH ∼3) and alkalic (pH ∼11) aqueous solution, the sorbent amidoximated in neutral (pH ∼7) NH₂OH aqueous solution achieved higher uranium adsorption capacities in both uranium-spiked brine (112.4 mg/g) and simulated seawater (7.4 mg/g). Additionally, potassium hydroxide (KOH) treatment was a necessary process and indeed significantly increased the uranium adsorption capacity.

Radiation-Induced In Situ-Printed Nonconjugated Fluorescent Nonwoven Fabric with Superior Fluorescent Properties

A new technique is proposed for the in situ printing of fluorescent fabrics with superior fluorescent properties that have the potential for continuous roll-to-roll production in the industry. Nonconjugated chemical moieties were covalently connected to polyethylene/polypropylene nonwoven fabric (PE/PP NWF) to successfully prepare fluorescent PE/PP NWF, which emits a bright blue light and has a high quantum yield (∼83.35%) that can be attributed to a unique aggregation-induced emission effect. The fluorescent PE/PP NWF exhibits excellent fluorescent stability under high shear forces during accelerated laundering and in harsh chemical environments. The fluorescent PE/PP NWF can also be tailored into diverse shapes and printed in situ with high resolution. The versatility of the method was also demonstrated by fabricating fluorescent materials with different polymer matrices such as Nylon 66 fiber and PE terephthalate membrane.

Pyruvate Kinase M2 Promotes Prostate Cancer Metastasis Through Regulating ERK1/2-COX-2 Signaling

Pyruvate kinase M2 (PKM2) is a key enzyme of glycolysis, which is highly expressed in many tumor cells, and has emerged as an important player in tumor progression and metastasis. However, the functional roles of PKM2 in tumor metastasis remain elusive. Here we showed that PKM2 promoted prostate cancer metastasis via extracellular-regulated protein kinase (ERK)-cyclooxygenase (COX-2) signaling. Based on public databases, we found that PKM2 expression was upregulated in prostate cancer and positively associated with tumor metastasis. Further analysis showed that PKM2 promoted prostate cancer cell migration/invasion and epithelial-mesenchymal transition (EMT) through upregulation of COX-2. Mechanistically, PKM2 interacted with ERK1/2 and regulated its phosphorylation, leading to phosphorylation of transcription factor c-Jun, downstream of ERK1/2, to activate COX-2 transcription by IP and ChIP assay, while inhibition of COX-2 significantly reversed the promotion effect of PKM2 on tumor metastasis in vivo. Taken together, our results suggest that a novel of PKM2-ERK1/2-c-Jun-COX-2 axis is a potential target in controlling prostate cancer metastasis.

Identifying the Origin of Ti3+ Activity toward Enhanced Electrocatalytic N2 Reduction over TiO2 Nanoparticles Modulated by Mixed-Valent Copper

The ambient electrocatalytic N₂ reduction reaction (NRR) enabled by TiO₂ has attracted extensive recent attention. Previous studies suggest the formation of Ti³⁺ in TiO₂ can significantly improve the NRR activity, but it still remains unclear what kinds of Ti³⁺ are effective. Herein, it is demonstrated that mixed-valent Cu acts as an effective dopant to modulate the oxygen vacancy (V_O ) concentration and Ti³⁺ formation, which markedly improves the electrocatalytic NRR performance. In 0.5 m LiClO₄ , this electrocatalyst attains a high Faradic efficiency of 21.99% and a large NH₃ yield of 21.31 µg h^-1 mg_cat. ^-1 at -0.55 V vs reversible hydrogen electrode, which even surpasses most reported Ti-based NRR electrocatalysts. Using density function theory calculations, it is evidenced that mixed-valent Cu ions modulate the TiO₂ (101) surface with multiple oxygen vacancies, which is beneficial for generating different Ti³⁺ 3d¹ defect states localized below the Fermi energy. N₂ activation and adsorption are effectively strengthened when Ti³⁺ 3d¹ defect states present the splitting of e_g and t_2g orbitals, which can be modulated by its coordination structure. The synergistic roles of the three ion pairs formed by the V_O defect, including Cu¹⁺ -Ti⁴⁺ , Ti³⁺ -Ti⁴⁺ and Ti³⁺ -Ti³⁺ , are together responsible for the enhanced NRR performance.

Altered Surface Hydrophilicity on Copolymer Scaffolds Stimulate the Osteogenic Differentiation of Human Mesenchymal Stem Cells

BACKGROUND

Recent studies have suggested that both poly(l-lactide-co-1,5-dioxepan-2-one) (or poly(LLA-co-DXO)) and poly(l-lactide-co-ε-caprolactone) (or poly(LLA-co-CL)) porous scaffolds are good candidates for use as biodegradable scaffold materials in the field of tissue engineering; meanwhile, their surface properties, such as hydrophilicity, need to be further improved.

METHODS

We applied several different concentrations of the surfactant Tween 80 to tune the hydrophilicity of both materials. Moreover, the modification was applied not only in the form of solid scaffold as a film but also a porous scaffold. To investigate the potential application for tissue engineering, human bone marrow mesenchymal stem cells (hMSCs) were chosen to test the effect of hydrophilicity on cell attachment, proliferation, and differentiation. First, the cellular cytotoxicity of the extracted medium from modified scaffolds was investigated on HaCaT cells. Then, hMSCs were seeded on the scaffolds or films to evaluate cell attachment, proliferation, and osteogenic differentiation. The results indicated a significant increasing of wettability with the addition of Tween 80, and the hMSCs showed delayed attachment and spreading. PCR results indicated that the differentiation of hMSCs was stimulated, and several osteogenesis related genes were up-regulated in the 3% Tween 80 group. Poly(LLA-co-CL) with 3% Tween 80 showed an increased messenger Ribonucleic acid (mRNA) level of late-stage markers such as osteocalcin (OC) and key transcription factor as runt related gene 2 (Runx2).

CONCLUSION

A high hydrophilic scaffold may speed up the osteogenic differentiation for bone tissue engineering.

Biological responses of dental pulp cells to surfaces modified by collagen 1 and fibronectin

Collagen 1 (COL1) and fibronectin (FN) are extracellular matrix proteins that contribute in cell activity and involve in regulating dental pulp cells (DPCs). The purpose of this study was to investigate the effect of COL1 and FN on the behavior of DPCs. Here, DPCs were grown under three different conditions: COL1 coating, FN coating, and control group without coating. The proliferation and differentiation of DPCs were investigated. DPCs in osteogenic media were able to differentiate into osteoblastic phenotype. The morphological analysis revealed no obvious difference on the shape of cells. Cells had spread well on both coated and noncoated culture plates with slightly more spreading in the coated plates after 24 hr. The MTT analysis did not demonstrate a significant difference at 1 and 3 hr among the groups, but interestingly, the analysis disclosed more cells on the coated plates after longer cultures, which indicated a higher proliferative capacity in response to COL1 and FN. RT-PCR, Western Blotting and mineralization assays did not reveal significant differences between the coated and noncoated surfaces in relation to osteogenic differential potential. Our data suggested that the surface coating of COL1 and FN were able to promote cellular proliferation and the osteogenic differentiation tendency of DPCs was also observed in vitro.

Surface Modification of 3D-Poly(glycerol-sebacate)/ Poly(L-lactic-acid) Porous Scaffolds by Oxygen Plasma Enhances Proliferation and Differentiation of Goat Temporomandibular Joint Disc Cells

3D poly(glycerol-sebacate)/poly(L-lactic-acid) (PGS/PLLA) scaffolds, produced by thermally induced phase separation (TIPS) method were treated with oxygen plasma in order to reduce the hydrophobicity of the PGS/PLLA membranes. After the oxygen plasma treatment, the pore size of scaffolds became uniform as well as an increasing in the roughness of the surface. No influence on chemical characteristics such as composition and bond types of PLLA was detected after the treatment. However, the change in the ratio of the scaffold elements before and after the oxygen plasma treatment was detected. Oxygen plasma treatment reduced the average of water contact angle of the TIPS film from 103.7± 10.1 to 64.7± 12.6 at the maximum exposure time (970 s) and power (100 W). The results showed that the goat temporomandibular joint (TMJ) cells attached well to the surface of the oxygen plasma modified scaffold. Furthermore, this modification significantly enhanced cell viability, increased cell proliferation and expression of related genes (Collagen type I mRNA and Collagen type II mRNA). The results demonstrated that it is a promising modification method to promote applications of PGS/PLLA based scaffolds to the regeneration of TMJ discs.

Retirement planning: the perceptions of pre-retirement nurses within different hospitals in China

AIM

This study explored the perceptions of senior Chinese nurses working in different hospital types, about retirement planning; and compared the results from two hospitals.

BACKGROUND

A recent review indicates that nurses with inadequate retirement planning could be faced with a retirement crisis. In China, hospitals are classified into different levels, and salaries, job satisfaction and the turnover of nurses varies among these levels. These factors may also influence nurses' perceptions of retirement planning.

METHODS

In a descriptive, qualitative design, 27 semi-structured individual interviews were conducted with nurses who were between 50 and 60 years old and recruited from two hospitals in China from April to September 2018. The interviews were transcribed and analysed thematically.

FINDINGS

Four main themes emerged from the interviews, namely, the understanding of pre-retirement nurses of retirement planning, the attitudes of pre-retirement nurses towards retirement planning, factors influencing nurses' retirement planning and the retirement planning activity of nurses. Most nurses participating in this study did not know much about retirement planning, but they all agreed on its importance. We identified the influencing factors of retirement planning and several differences regarding the perceptions of nurses about retirement planning in different hospitals.

CONCLUSION

In this cohort of nurses, planning for a good retirement was thought to be important; however, their readiness for retirement and the influences around planning for retirement were varied in type and scope.

IMPLICATIONS FOR POLICY

Governments and employing hospitals should develop reasonable measures and policies to support nurses in their understanding of the benefits of retirement planning and help them to prepare for retirement. Information about retirement planning should be made available and options for planning explained. Any systematic hurdles to retirement planning should be mitigated or eliminated.

Wnt3 knockdown sensitizes human non-small cell type lung cancer (NSCLC) cells to cisplatin via regulating the cell proliferation and apoptosis

OBJECTIVE

Aberrant activation of (Wingless and mouse homolog Int-1) Wnt/β-catenin signaling pathways closely involved in the occurrence and progression of several types of human malignancies. This research was undertaken to elucidate the important role of (Wingless and mouse homolog Int-1) in lung cancer.

PATIENTS AND METHODS

Wnt3 expression in lung cancers and their respective normal tissues were examined by immunoblotting and immunohistochemistry. Then, Wnt3 was regulated with RNA interference (RNAi) technology in human lung cancer A549 cells, and the cell proliferation, cell cycle, cell invasion/metastasis, and apoptosis were evaluated.

RESULTS

In all cases, Wnt3 expression was significantly elevated in lung cancers compared with normal tissues. Knocking down Wnt3 in A549 lung cancer cells by small interfering RNAs transfection led to a distinct reduction of Wnt3 in both transcript and protein levels. Knockdown of Wnt3 expression in lung cancer cells inhibited the expression of β-catenin and cyclin D1 genes in Wnt/β-catenin pathway. It also significantly blocked cellular proliferation, delayed cell cycle and suppressed cell invasion/metastasis, accompanied by a higher apoptosis rate.

CONCLUSIONS

We conclude that the upregulation of Wnt3 plays a crucial role in lung tumorigenesis by inducing proliferation, migration, and invasion and inhibiting apoptosis of cancer cells. Wnt3 might be a potential target for the treatment of lung cancer.

Neck masses in children: a 10-year single-centre experience in Northwest China

Neck masses in children are a common clinical concern but there is a paucity of published information about them. We organised this retrospective study to analyse their prevalence and treatment in Northwest China. The records of 207 children who presented with neck masses between 2008 and 2017 were retrieved from the Department of Oral and Maxillofacial Surgery, Lanzhou University Second Hospital, and age, sex, clinical presentation, preoperative investigation, surgical procedure, histopathological diagnosis, and complications were recorded. Their mean (range) age was 10 years (6 months to 21 years), and the male:female ratio was 1.23:1. In total 128 patients (62%) had congenital lesions, 35 (17%) had inflammatory lesions, and 44 (21%) had neoplastic lesions. The most common mass was a thyroglossal cyst (31%), followed by plunging ranula (17%) and lymphangioma (16%). Temporary injury to the facial nerve and wound infection were the major complications of surgical treatment. The types of neck masses in Northwest China differ from those previously reported, which may be attributed to genetic alterations in people of this race. The present report adds to the knowledge of diagnosis and treatment of neck masses in children in Northwest China, and brings out the demographic differences between races.

Adenoviral mediated mono delivery of BMP2 is superior to the combined delivery of BMP2 and VEGFA in bone regeneration in a critical-sized rat calvarial bone defect

Apart from osteogenesis, neovascularization of the defect area is an important determinant for successful bone healing. Accordingly, several studies have employed the combined delivery of VEGFA and BMP2 for bone regeneration. Nevertheless, the outcomes of these studies are highly variable. The aim of our study was to compare the effectiveness of adenoviral mediated delivery of BMP2 alone and in combination with VEGFA in rat bone marrow stromal cells (rBMSC) seeded on a poly(LLA-co-CL) scaffold in angiogenesis and osteogenesis using a critical-sized rat calvarial defect model. Both mono delivery of BMP2 and the combined delivery of a lower ratio of VEGFA and BMP2 (1:4) led to up-regulation of osteogenic genes (Alpl and Runx2) and increased calcium deposition in vitro, compared with the GFP control. Micro computed tomography (microCT) analysis of the rat calvarial defect at 8 weeks showed that the mono delivery of BMP2 (43.37 ± 3.55% defect closure) was the most effective in healing the bone defect, followed by the combined delivery of BMP2 and VEGFA (27.86 ± 2.89%) and other controls. Histological and molecular analyses supported the microCT findings. Analysis of the angiogenesis, however, showed that both mono delivery of BMP2 and combined delivery of BMP2 and VEGFA had similar angiogenic effect in the calvarial defects. Examination of the key genes related to host response against the adenoviral vectors showed that the current model system was not associated with adverse immune response. Overall, the results show that the mono delivery of BMP2 was superior to the combined delivery of BMP2 and VEGFA in healing the critical-sized rat calvarial bone defect. These findings underscore the importance of appropriate growth factor combination for the successful outcome in bone regeneration.

Direct imaging of ultrafast lattice dynamics

Under rapid high-temperature, high-pressure loading, lattices exhibit complex elastic-inelastic responses. The dynamics of these responses are challenging to measure experimentally because of high sample density and extremely small relevant spatial and temporal scales. Here, we use an x-ray free-electron laser providing simultaneous in situ direct imaging and x-ray diffraction to spatially resolve lattice dynamics of silicon under high-strain rate conditions. We present the first imaging of a new intermediate elastic feature modulating compression along the axis of applied stress, and we identify the structure, compression, and density behind each observed wave. The ultrafast probe x-rays enabled time-resolved characterization of the intermediate elastic feature, which is leveraged to constrain kinetic inhibition of the phase transformation between 2 and 4 ns. These results not only address long-standing questions about the response of silicon under extreme environments but also demonstrate the potential for ultrafast direct measurements to illuminate new lattice dynamics.

Exosome Release Is Regulated by mTORC1

Exosomes are small membrane-bound vesicles released into extracellular spaces by many types of cells. These nanovesicles carry proteins, mRNA, and miRNA, and are involved in cell waste management and intercellular communication. In the present study, it is shown that exosome release, which leads to net loss of cellular membrane and protein content, is negatively regulated by mechanistic target of rapamycin complex 1 (mTORC1). It is found that in cells and animal models exosome release is inhibited by sustained activation of mTORC1, leading to intracellular accumulation of CD63-positive exosome precursors. Inhibition of mTORC1 by rapamycin or nutrient and growth factor deprivation stimulates exosome release, which occurs concomitantly with autophagy. The drug-stimulated release is blocked by siRNA-mediated downregulation of small GTPase Rab27A. Analysis of the cargo content in exosomes released from rapamycin-treated cells reveals that inhibition of mTORC1 does not significantly alter its majority protein and miRNA profiles. These observations demonstrate that exosome release, like autophagy, is negatively regulated by mTORC1 in response to changes in nutrient and growth factor conditions.

Improving the Supercritical CO₂ Foaming of Polypropylene by the Addition of Fluoroelastomer as a Nucleation Agent

In this study, a small amount of fluoroelastomer (FKM) was used as a nucleating agent to prepare well-defined microporous PP foam by supercritical CO₂. It was observed that solid FKM was present as the nanoscale independent phase in PP matrix and the FKM could induce a mass of CO₂ aggregation, which significantly enhanced the diffusion rate of CO₂ in PP. The resultant PP/FKM foams exhibited much smaller cell size (~24 μm), and more than 16 times cell density (3.2 × 10⁸ cells/cm³) as well as a much more uniform cell size distribution. PP/FKM foams possessed major concurrent enhancement in their tensile stress and compressive stress compared to neat PP foam. We believe that the added FKM played a key role in enhancing the heterogeneous nucleation, combined with the change of local strain in the multiple-phase system, which was responsible for the considerably improved cell morphology of PP foaming. This work provides a deep understanding of the scCO₂ foaming behavior of PP in the presence of FKM.

Demonstration of a 120° hybrid based simplified coherent receiver on SOI for high speed PON applications

We demonstrate the first simplified coherent receiver using a 120° hybrid on silicon-on-insulator (SOI) for high speed PON applications. This coherent receiver integrates an inverse taper edge coupler for the received signal, a vertical grating coupler for the local oscillator input, a polarization splitter and rotator (PSR), a 120° hybrid based on a 3×3 multimode interference (MMI) coupler, and three germanium photodetectors. We achieved 25 Gbit/s two-level pulse amplitude modulation (PAM-2) transmission over 30 km standard single mode fiber (SMF) in the C-band without any digital signal processing (DSP) (e.g., pre-emphasis, pulse shaping, equalization, nonlinearity compensation) and dispersion compensation (e.g., optical or digital) either at the transmitter or at the receiver. The requirements for frequency and phase locking of the local oscillator (LO) were avoided due to the use of intensity modulated signals. Receiver sensitivities of -23.70 dBm, -20.30 dBm, and -15.10 dBm are achieved at a bit error rate (BER) below the hard-decision forward error correction (HD-FEC) threshold (i.e., 3.8 × 10^-3) in back-to-back (B2B), after 21 km and 30 km, respectively. We also demonstrate 25 Gbit/s PAM-4 transmission achieving receiver sensitivities of -15.30 dBm, -13.90 dBm, and -9.50 dBm below the HD-FEC threshold in B2B, after 10.5 km and 21 km, respectively.

Cadmium phytoavailability under greenhouse vegetable production system measured by diffusive gradients in thin films (DGT) and its implications for the soil threshold

The diffusive gradients in thin films (DGT) technique is recognized to have advantages over traditional techniques. For example, the passive measurement generally follows the principle of metal uptake by plants, and its result incorporates the influences of soil properties, which may make DGT a good protocol for improving soil quality guidelines (SQGs). However, DGT has rarely been applied to assess Cd phytoavailability in soils under greenhouse vegetable production (GVP) systems. In this study, 29 turnips (Raphanussativus L.), 21 eggplants (Solanum melongena L.) and their corresponding soils were collected from GVP systems in Dongtai and Shouguang, eastern China. Simple linear regression and stepwise regression were performed using the soil Cd content and soil properties to predict the vegetable Cd content. Soil thresholds were derived based on both total and available Cd concentrations. The results showed that total Cd, DGT-measured Cd (DGT-Cd), soil-solution Cd (Soln-Cd) and CaCl₂-extractable Cd (CaCl₂-Cd) were all significantly correlated with vegetable Cd. DGT-Cd had the best correlation with turnip Cd. The total Cd threshold values ranged from 4.87 (pH 6.5) to 5.18 (pH 7.5) mg kg^-1 for turnips and 14.60 (pH 6.5) to 14.90 (pH 7.5) mg kg^-1 for eggplants. These Cd thresholds were higher than the current SQGs. The predicted of turnip Cd by DGT-Cd was not improved significantly by further considering the soil properties. The calculated soil threshold of DGT-Cd was 5.35 μg L^-1 for turnips. However, the predicted soil threshold of DGT-Cd for eggplant was improved by including SOM, with R² values from 0.53 to 0.70. The DGT-Cd threshold was calculated as 1.81 μg L^-1 for eggplant (30.0 g kg^-1 SOM). In conclusion, whether DGT measurements are independent of soil properties and preferable for the evaluation of Cd phytoavailability and the generation of soil thresholds remains to be clarified in future research.