Bio-based P-N flame retardant with ZIF-67 in-situ growth on flexible polyurethane foam with excellent fire safety performance.

The wide application of flexible polyurethane foam (FPUF) poses a giant challenge to human society in terms of fire prevention and environmental pollution. To solve this problem, the lignocellulose-based P-N flame retardant (LFPN) has been developed using mechanochemical methods. It was found that FPUF treated using LFPN exhibited good flame retardancy, but suffered from high smoke generation and toxicity. The hollow dodecahedral ZIF-67 has been used for smoke suppression catalysis, but the agglomeration phenomenon makes it inefficient. Hence, in this study, the adhesive properties of polydopamine (PDA) were utilized to assist the in-situ growth of ZIF-67. The results showed that the total smoke release rate of the treated FPUF was reduced by 40.5%. The toxic gases, such as carbon monoxide (CO), hydrogen cyanide, etc., also showed the same decreasing trend. What's more, the catalytic effect of ZIF-67 itself and the synergistic effect with LFPN gave FPUF great flame retardant and smoke inhibition properties. This novel FPUF provides a new reference for achieving smoke suppression and toxicity reduction.

Enhancing the Photoluminescence and Electroluminescence of Graphitic Carbon Nitride via Atomic and Molecular Co-modification.

Graphitic carbon nitride (g-CN) materials exhibit attractive optoelectronic physical properties; however, their low photoluminescence quantum yields (PLQYs) limit their applications in luminescent devices. Here, boron-doped aromatic carbon nitride (B-PhCNx) was synthesized for the first time via direct thermal polymerization of 2,4-diamino-6-phenyl-1,3,5-triazine and boric acid. The impact of B doping and phenyl modifying on the structural and optical characteristics of the samples was investigated in detail. The highest PLQY of 40.7% was achieved in B-PhCN20, which is 6.8 times that of pristine carbon nitride (p-CN). The B-PhCN20-based light-emitting diode demonstrates a maximum luminance of 1494 cd m-2 and a maximum external quantum efficiency of 1.03%, which are 3.5 and 4.9 times that of the p-CN-based device, respectively. Our findings will provide a reference for rationally designing low-cost and high-performance carbon-nitride-based optoelectronic devices.

High TSLP responses in the human infant airways are associated with pre-activated airway epithelial IFN antiviral immunity.

Thymic stromal lymphopoietin (TSLP) is a primarily epithelial-derived cytokine that drives type 2 allergic immune responses. Early life viral respiratory infections elicit high TSLP production, which leads to the development of type 2 inflammation and airway hyperreactivity. The goal of this study was to examine in vivo and in vitro the human airway epithelial responses leading to high TSLP production during viral respiratory infections in early infancy. A total of 129 infants (<1-24 m, median age 10 m) with severe viral respiratory infections were enrolled for in vivo (n = 113), and in vitro studies (n = 16). Infants were classified as 'high TSLP' or 'low TSLP' for values above or below the 50th percentile. High versus low TSLP groups were compared in terms of type I-III IFN responses and production of chemokines promoting antiviral (CXCL10), neutrophilic (CXCL1, CXCL5, CXCL8), and type 2 responses (CCL11, CCL17, CCL22). Human infant airway epithelial cell (AEC) cultures were used to define the transcriptomic (RNAseq) profile leading to high versus low TSLP responses in vitro in the absence (baseline) or presence (stimulated) of a viral mimic (poly I:C). Infants in the high TSLP group had greater in vivo type III IFN airway production (median type III IFN in high TSLP 183.2 pg/mL vs. 63.4 pg/mL in low TSLP group, p = 0.007) and increased in vitro type I-III IFN AEC responses after stimulation with a viral mimic (poly I:C). At baseline, our RNAseq data showed that infants in the high TSLP group had significant upregulation of IFN signature genes (e.g., IFIT2, IFI6, MX1) and pro-inflammatory chemokine genes before stimulation. Infants in the high TSLP group also showed a baseline AEC pro-inflammatory state characterized by increased production of all the chemokines assayed (e.g., CXCL10, CXCL8). High TSLP responses in the human infant airways are associated with pre-activated airway epithelial IFN antiviral immunity and increased baseline AEC production of pro-inflammatory chemokines. These findings present a new paradigm underlying the production of TSLP in the human infant airway epithelium following early life viral exposure and shed light on the long-term impact of viral respiratory illnesses during early infancy and beyond childhood.

A biomimetic design for efficient petrochemical spill disposal: CoFe-PBA modified superhydrophobic melamine sponge with mechanical/chemical durability and low fire risk.

Due to frequent petrochemical spills, environmental pollution and the threat of secondary marine fires have arisen, necessitating an urgent need for petrochemical spill treatment strategies with high-performance oil-water separation capabilities. To address the challenges of poor durability, instability in hydrophobic conditions, and difficulty in absorbing high-viscosity crude oil associated with hydrophobic absorbent materials, the authors of this study took inspiration from the unique micro and nanostructures of springtails' water-repellent skin. We engineered a superhydrophobic melamine sponge using interfacial assembly techniques designated as Si@PBA@PDA@MS. This material demonstrated improved mechanical and chemical durability, enhanced photothermal performance, and reduced fire risk. The metal-organic framework (MOF)-derived cobalt-iron Prussian blue analog (CoFe-PBA) was firmly anchored to the sponge framework by the chelation of cobalt ions using polydopamine (PDA). The results demonstrated that Si@PBA@PDA@MS demonstrated excellent superhydrophobicity (WCA=163.5°) and oil absorption capacity (53.4-97.5 g/g), maintaining high durability even after 20 cycles of absorption-squeezing. Additionally, it could still exhibit excellent mechanical properties, hydrophobic stability, and absorption performance across a wide temperature range (0-100 °C), pH range (1-14), and high compression strength (ε = 80%), with excellent mechanical/chemical durability. Furthermore, Si@PBA@PDA@MS demonstrated remarkable photothermal performance and low fire risk, offering efficient, safe, and sustainable practical value for effective petrochemical spill treatment.

A High-Efficient DOPO-Based Flame Retardant as a Co-Curing Agent for Simultaneously Enhancing the Fire Safety and Mechanical Properties of Epoxy Resin.

Simultaneously enhancing the fire safety and mechanical properties of epoxy resin (EP) remains a persistent challenge. Herein, a high-efficient phosphaphenanthrene-based flame retardant (FNP) is synthesized using 3,5-diamino-1,2,4-triazole, 4-formylbenzoic acid, and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide. Due to the presence of active amine groups, FNP is employed as a co-curing agent for fabricating EP composites with outstanding fire safety and mechanical properties. EP containing 8 wt% FNP (EP/8FNP) achieves a vertical burning (UL-94) V-0 rating with a limiting oxygen index of 31%. Meanwhile, FNP declines the peak heat release rate, total heat release, and total smoke release of EP/8FNP by 41.1%, 31.8%, and 16.0%, respectively, compared to those of unmodified EP. The increased fire safety of EP/FNP composites is because FNP promotes the formation of an intumescent, compact, and cross-linking char layer for EP/FNP composites, and releases P-containing substances and noncombustible gases in the gas phase during combustion. In addition, EP/8FNP exhibits 20.3% and 5.4% increase in the flexural strength and modulus compared with those of pure EP. Furthermore, FNP enhances the glass transition temperature of EP/FNP composites from 141.6 °C for pure EP to 147.3 °C for EP/8FNP. Therefore, this work is conducive to the future development of fabricating fire-safe EP composites with enhanced mechanical properties.

Organic Phosphoric Acid Doped Polyaniline-Coupled g-C3 N4 for Enhancing Fire Safety of Intumescent Flame-Retardant Epoxy Resin.

Two kinds of polyaniline coupled graphitized carbon nitride nanosheets doped with different organic phosphoric acids (CP@PA, with phytic acid; CP@NP, with amino trimethyl phosphonic acid) are developed by in-situ polymerization. According to the analysis of the section morphology and element distribution of epoxy resin (EP) composites, although CP@PA and CP@NP show completely different morphology, they can significantly enhance the dispersion of graphitized carbon nitride nanosheets in EP. Moreover, the different oxidation states of phosphorus contained in the CP@PA and CP@NP lead to varying effects on the fire safety of EP. The flame retardancy Index (FRI) is a dimensionless index to evaluate the performance of flame retardants. When used as a flame retardant, CP@NP (FRI = 3.22) is better than CP@PA (FRI = 1.29) in flame retardant, especially in suppressing thermal hazards. As a synergist of intumescent flame retardants (IFR), CP@PA (FRI = 26.12) is most effective in improving the comprehensive fire safety property of EP and achieves an "Excellent" rating. Therefore, two different flame-retardant mechanisms of CP@PA and CP@NP are summarized by analyzing the combustion behavior and changes of condensed phase. In summary, this research may be helpful to the design of nano synergies for IFR systems.

MOF-derived LDH modified flame-retardant polyurethane sponge for high-performance oil-water separation: Interface engineering design based on bioinspiration.

Frequent petrochemical spill accidents and secondary fire hazards have threatened the ecological environment and environmental safety. The traditional purification technology has the problems of high energy consumption and secondary pollution, which also brings new challenges to spill disposal. Herein, we demonstrate a biomimetic structure-based flame-retardant polyurethane (PU) sponge (FPUF@MOF-LDH@HDTMS) for continuous oil-water separation. Inspired by desert beetle and lotus leaf, the biomimetic micro-nano composite structure was constructed by in-situ growth of metal-organic framework-derived layered double hydroxide (MOF-LDH) on the surface of the PU sponge. After grafting MOF-LDH with hexadecyltrimethoxysilane, FPUF@MOF-LDH@HDTMS showed excellent superhydrophobic/superoleophilic performance (water contact angle=153° and oil contact angle=0°). FPUF@MOF-LDH@HDTMS can easily and quickly adsorb oily liquids suspended/settled in the water thanks to the unique bionic structure. FPUF@MOF-LDH@HDTMS has excellent oil/organic solvents absorption capacity; even after 20 cycles of use still maintains high adsorption capacity. More importantly, the continuous oil-water separation through FPUF@MOF-LDH@HTMS has achieved a separation efficiency of up to 99.1%. In addition, the bionic superhydrophobic sponge has excellent flame retardancy, which reduces the possibility of secondary fire caused by PU sponges. Thus, the biomimetic micro-nano composite structure provides a new design strategy for the more high-performance oil-water separation sponges.

Co-curing preparation of flame retardant and smoke-suppressive epoxy resin with a novel phosphorus-containing ionic liquid.

Phosphorus-containing ionic liquid derivatives have been proven to be effective flame retardants for epoxy resin (EP). Flame retardants can accelerate the curing process and improve flame retardancy and smoke suppression of EP composites, which is challenging. In this paper, a novel phosphorus-containing ionic liquid (TPP-PF6) was synthesized and used both as a co-curing agent with 4,4'-diaminodiphenylmethane (DDM) and as a highly effective flame retardant for EP. It has been found that TPP-PF6 was conducive to improve the char formation of EP to inhibit the smoke release at high temperatures. For EP/TPP-PF6 composites, the flame-retardant performance was enhanced rapidly with the increase of TPP-PF6. With only 2 wt% of TPP-PF6, EP/2.0TPP-PF6 reached a UL-94 V-0 rating and a limiting oxygen index of 30.3%. The peak heat release rate, total heat release, and total smoke production values of EP/2.0TPP-PF6 were reduced by 36.32%, 45.81%, and 15.1% compared with those of pure EP, respectively. The thermal degradation products and flame retardant mechanism in gas and condensed phases were studied. It was found that TPP-PF6 had flame retardant effect in the barrier effect of the condensed phase and the quenching effect of the gas phase. This work explores the high-efficiency flame retardant and smoke-suppressive structures with co-curing properties for EP, thus promoting the wide application of EP materials.

Synthesis of sugar gourd-like metal organic framework-derived hollow nanocages nickel molybdate@cobalt-nickel layered double hydroxide for flame retardant polyurea.

Transition metals with catalytic properties were expected to improve the fire resistance of the polymer. In this work, NiMoO4 nanorods decorated with Co-Ni layered double hydroxide (LDH) were fabricated and incorporated into polyurea (PUA) to improve the flame retardancy during combustion. Thermogravimetric analysis (TGA) showed that the addition of NiMoO4@Co-Ni LDH slightly decreased the initial degradation and the maximum degradation temperature. With increasing loading of NiMoO4@Co-Ni LDH, the char residue increased obviously. The combustion performance of PUA with 3.0 wt% NiMoO4@Co-Ni LDH investigated by cone calorimeter (CCT) showed that the peak heat release rate (PHRR), total heat release (THR) and smoke factor (SF) decreased by 34.41%, 12.68% and 48.65%, respectively. The existence of well-dispersed NiMoO4@Co-Ni LDH effectively enhanced the mechanical properties and flame retardant performances of PUA.

Mixture Phases Engineering of PtFe Nanofoams for Efficient Hydrogen Evolution.

Phase engineering is a promising but challenging approach to construct PtFe-based catalysts with efficient hydrogen evolution reaction (HER) performance. Herein, the authors successfully synthesize PtFe nanofoams with face center cubic (fcc) phase, with simple cubic crystalline (scc) phase and with the mixture phases of fcc and scc phases (PtFe-mix) by hydrogen-assisted calcination for the first time. By benchmarking the HER activity, PtFe-mix exhibits excellent activity in 1.0 m KOH, requiring an overpotential of 28 mV to achieve 10 mA cm-2 , which is better than the commercial Pt/C (34 mV). PtFe-mix also possesses remarkable stability up to 24 h. Density functional theory calculations further verify that PtFe-mix shows a more suitable d-band center and lower energy barrier for the initial water dissociation, facilitating the HER process. This work provides a meaningful strategy to design PtFe-based catalysts with efficient activity for hydrogen evolution.

Noble Metal (Pt, Rh, Pd, Ir) Doped Ru/CNT Ultra-Small Alloy for Acidic Hydrogen Evolution at High Current Density.

There are still great challenges to prepare high-efficiency Ru-based catalysts that are superior to Pt/C under acidic conditions, especially under high current conditions. In this work, a series of surfactant-free noble metal doped Ru/CNT (M-Ru/CNT, M = Pt, Rh, Pd, Ir, CNT stands for carbon nanotube) are prepared by microwave reduction method in 1 minute with ≈3-3.5 nm in size for the first time. In 0.5 m H2 SO4 , the overpotential of Pt-Ru/CNT (Pt: 4.94 at %) is only 12 mV. What's more, it also has much larger electrochemical surface area and intrinsic activity than Pt/C. Pt-Ru/CNT still has an ultra-small overpotential under high current density (113 mV at 500 mA cm-2 , 155 mV at 1000 mA cm-2 ). At the same time, it possesses excellent stability regardless of high current or low current after the durability test of 100 h. Theoretical calculation also deeply reveals that Ru is the main adsorption site of H+ . The comparison of the electronic structure of a series of noble metals adjusted by Ru shows that Pt has the most excellent Gibbs free energy of the adsorbed hydrogen and promotes the desorption of the product.

The airway epithelium during infancy and childhood: A complex multicellular immune barrier. Basic review for clinicians.

The airway epithelium is a complex multicellular layer that extends from the nasopharynx to the small airways. It functions as an immune respiratory barrier during early life that develops, matures, and regenerates to adapt to the changes in the environment. While airway epithelial abnormalities have been identified in several clinical disorders, there is increasing interest in understanding its basic regulation and structure in humans. Indeed, recent advances in technology (e.g. single-cell analysis and new human airway epithelial cell models) have allowed us to identify additional cellular subtypes and functions that overall have greatly improved our understanding of the airway epithelium during health and disease. In this review we summarize key features of the airway epithelium including: 1) multilayer structure and cell heterogeneity; 2) adaptability to different environmental and developmental stimuli; 3) innate recognition; and 4) orchestration of immune responses. We discuss these features with a translational and clinical prospective focusing on the development of human respiratory immunity, particularly during early life.

The interplay between airway epithelium and the immune system - A primer for the respiratory clinician.

The respiratory epithelium is one of the primary interfaces between the body's immune system and the external environment. This review discusses the innate and adaptive immunomodulatory effects of the respiratory epithelium, highlighting the physiologic immune responses associated with health and the disease-causing sequelae when these physiologic responses go awry. Airway macrophages, dendritic cells, and innate lymphoid cells are discussed as orchestrators of physiological and pathological innate immune responses and T cells, B cells, mast cells, and granulocytes (eosinophils and neutrophils) as orchestrators of physiologic and pathologic adaptive immune responses. The interplay between the airway epithelium and the varied immune cells as well as the interplay between these immune cells is discussed, highlighting the importance of the dose of noxious stimuli and pathogens in immune programming and the timing of their interaction with the immune cells that determine the pattern of immune responses. Although each cell type has been researched individually, this review highlights the need for simultaneous temporal investigation of immune responses from these varied cells to noxious stimuli and pathogens.

Effect of Functionalized Carbon Microspheres Combined with Ammonium Polyphosphate on Fire Safety Performance of Thermoplastic Polyurethane.

In this article, carbon microspheres (CMSs) synthesized by the hydrothermal method and CMSs-Fe (with Fe3+ adsorbed on the surface of CMSs) were combined with ammonium polyphosphate (APP) to achieve the fire safety improvement of thermoplastic polyurethane (TPU). The fire safety performance of TPU composites was investigated by the cone calorimeter test, microscale combustion calorimeter test, thermogravimetric analysis/infrared spectrometry, Raman spectrometry, X-ray photoelectron spectroscopy, and scanning electron microscopy. The results showed that CMSs and CMSs-Fe can improve the fire safety performance of TPU/APP composites and the effect of CMSs-Fe was better than that of CMSs. The peak heat release rate of the sample containing 0.25 wt % CMSs and 7.75 wt % APP was 16.7% lower than that of the sample containing 8.00 wt % APP, and the content of toxic gases was also reduced in the fire smoke. Also, total heat release and total smoke release of the sample containing CMSs-Fe were 54.7% and 11.6%, respectively, lower than those of the sample containing 0.25% CMSs. It confirmed the contribution of CMSs to the flame retardant system, and the performance of CMSs is improved by adsorbing Fe3+.

Hypophosphite/Graphitic Carbon Nitride Hybrids: Preparation and Flame-Retardant Application in Thermoplastic Polyurethane.

A series of aluminum hypophosphite (AHPi)/graphite-like carbon nitride (g-C3N4) (designated as CAHPi) hybrids were prepared, followed by incorporation into thermoplastic polyurethane (TPU). The introduction of CAHPi hybrids into TPU led to a marked reduction in the peak of the heat release rate (pHRR), total heat release, weight loss rate, smoke production rate and total smoke production (TSP). For instance, pHRR and TSP decreased by 40% and 50% for TPU/CAHPi20. Furthermore, the increasing fire growth index and decreasing fire performance index were obtained for TPU/CAHPi systems, suggesting reduced fire hazards. It was found that improved fire safety of TPU nanocomposites was contributed by condensed phase and gas phase mechanisms. On one hand, g-C3N4 accelerated the thermal decomposition of AHPi for the formation of more char layers. On the other hand, g-C3N4 induced AHPi to generate more free radical capture agents when exposed to flame, besides protecting AHPi against thermal oxidation.

A recycled environmental friendly flame retardant by modifying para-aramid fiber with phosphorus acid for thermoplastic polyurethane elastomer.

The application of fibers is more and more extensive, and the pollution caused by abandoned fibers is getting more serious, which has aroused wide attention. So it is necessary to find a way to solve the problem. In this paper, the para-aramid fiber (AF) was recycled and modified by phosphoric acid, and then was applied as environmental friendly flame retardant for thermoplastic polyurethane elastomer (TPU). The flame retardant properties of TPU were tested using cone calorimeter test (CCT) and thermogravimetric/Fourier transform infrared spectroscopy (TG-IR). The CCT test showed that AF-P had better flame retardant effect on TPU than pure AF. Remarkably, the pHRR value for the sample with 1.00wt% content of AF-P was decreased by 48.1%; AF-P had improved the char forming progress and the residual mass was 30.6%, which was much more than pure TPU. TG test showed that AF-P could improve the thermal stability of TPU at high temperature. The TG-IR test revealed that AF-P had reduced the release of CO2 at the beginning. Based on the above results, it will make a great influence on the study of reuse of fibers and environmental friendly flame retardant of polymer.

Fire hazard reduction of hollow glass microspheres in thermoplastic polyurethane composites.

Nowadays, reducing the fire hazard of thermoplastic polyurethane (TPU) is an important research direction in the fields of fire safety materials. In this article, hollow glass microsphere (HGM) was used to reduce the fire hazard of TPU in combustion process. The fire characteristics including smoke and heat production of TPU composites were evaluated using smoke density test (SDT) and cone calorimeter test (CCT). And the thermal decomposition and flammable properties were further studied using thermogravimetric analysis/infrared spectrometry (TG-IR) and limiting oxygen index (LOI), etc. The SDT results showed that the luminous flux (LF) of TPU4 containing 2.00wt% HGM was up to 24% at the end of test without flame, which is much higher than that of TPU0 (5%). And, the CCT results indicated that 2.00wt% HGM could make the total smoke release (TSR) decrease from 1019m2/m2 (TPU0) to 757m2/m2 (TPU4), reduced by 26%. The TG-IR results confirmed that HGM could improve the thermal stability of composites and reduce the production of some toxic gases. The above results illustrated HGM had a good prospect in reducing the fire hazard for TPU.

Fire safety improvement of para-aramid fiber in thermoplastic polyurethane elastomer.

This article mainly studied fire safety effects of para-aramid fiber (AF) in thermoplastic polyurethane (TPU). The TPU/AF composites were prepared by molten blending method, and then the fire safety effects of all TPU composites were tested using cone calorimeter test (CCT), microscale combustion colorimeter test (MCC), smoke density test (SDT), and thermogravimetric/fourier transform infrared spectroscopy (TG-IR). The CCT test showed that AF could improve the fire safety of TPU. Remarkably, the peak value of heat release rate (pHRR) and the peak value of smoke production rate (pSPR) for the sample with 1.0wt% content of AF were decreased by 52.0% and 40.5% compared with pure TPU, respectively. The MCC test showed that the HRR value of AF-2 decreased by 27.6% compared with pure TPU. TG test showed that AF promoted the char formation in the degradation process of TPU; as a result the residual carbon was increased. The TG-IR test revealed that AF had increased the thermal stability of TPU at the beginning and reduced the release of CO2 with the decomposition going on. Through the analysis of the results of this experiment, it will make a great influence on the study of the para-aramid fiber in the aspect of fire safety of polymer.

Identification of galectin-1 as a novel mediator for chemoresistance in chronic myeloid leukemia cells.

Multidrug resistance protein-1 (MDR1) has been proven to be associated with the development of chemoresistance to imatinib (Glivec, STI571) which displays high efficacy in treatment of BCR-ABL-positive chronic myelogenous leukemia (CML). However, the possible mechanisms of MDR1 modulation in the process of the resistance development remain to be defined. Herein, galectin-1 was identified as a candidate modulator of MDR1 by proteomic analysis of a model system of leukemia cell lines with a gradual increase of MDR1 expression and drug resistance. Coincidently, alteration of galectin-1 expression triggers the change of MDR1 expression as well as the resistance to the cytotoxic drugs, suggesting that augment of MDR1 expression engages in galectin-1-mediated chemoresistance. Moreover, we provided the first data showing that NF-κB translocation induced by P38 MAPK activation was responsible for the modulation effect of galectin-1 on MDR1 in the chronic myelogenous leukemia cells. Galectin-1 might be considered as a novel target for combined modality therapy for enhancing the efficacy of CML treatment with imatinib.