Regulating Electrostatic Interactions toward Thermoresponsive Hydrogels with Low Critical Solution Temperature.

Low critical solution temperature (LCST) of commonly used thermoresponsive polymers in water is basically dominated by hydrophobic interactions. Herein, a novel thermoresponsive system based on electrostatic interactions is reported. By simply loading aluminum chloride (AlCl3 ) into non-responsive poly(2-hydroxyethyl acrylate) (PHEA) hydrogels, PHEA-Al gels turn to have reversible thermoresponsive behavior between transparent and opaque without any volume change. Further investigations by changing metal ion-polymer compositions unravel the necessity of specific electrostatic interactions, namely, cation-dipole bonding interactions between hydroxy groups and trivalent metal ions. The thermoresponsive hydrogel demonstrates high transparency (≈95%), excellent luminous modulation capability (>98%), and cyclic reliability, suggesting great potential as an energy-saving material. Although LCST control by salt addition is widely known, salt-induced expression of thermoresponsiveness has barely been discussed before. This design provides a new approach of easy fabrication, low cost, and scalability to develop stimuli-responsive materials.

Polystyrene nanoplastics with different functional groups and charges have different impacts on type 2 diabetes.

BACKGROUND: Increasing attention is being paid to the environmental and health impacts of nanoplastics (NPs) pollution. Exposure to nanoplastics (NPs) with different charges and functional groups may have different adverse effects after ingestion by organisms, yet the potential ramifications on mammalian blood glucose levels, and the risk of diabetes remain unexplored. RESULTS: Mice were exposed to PS-NPs/COOH/NH2 at a dose of 5 mg/kg/day for nine weeks, either alone or in a T2DM model. The findings demonstrated that exposure to PS-NPs modified by different functional groups caused a notable rise in fasting blood glucose (FBG) levels, glucose intolerance, and insulin resistance in a mouse model of T2DM. Exposure to PS-NPs-NH2 alone can also lead the above effects to a certain degree. PS-NPs exposure could induce glycogen accumulation and hepatocellular edema, as well as injury to the pancreas. Comparing the effect of different functional groups or charges on T2DM, the PS-NPs-NH2 group exhibited the most significant FBG elevation, glycogen accumulation, and insulin resistance. The phosphorylation of AKT and FoxO1 was found to be inhibited by PS-NPs exposure. Treatment with SC79, the selective AKT activator was shown to effectively rescue this process and attenuate T2DM like lesions. CONCLUSIONS: Exposure to PS-NPs with different functional groups (charges) induced T2DM-like lesions. Amino-modified PS-NPs cause more serious T2DM-like lesions than pristine PS-NPs or carboxyl functionalized PS-NPs. The underlying mechanisms involved the inhibition of P-AKT/P-FoxO1. This study highlights the potential risk of NPs pollution on T2DM, and provides a new perspective for evaluating the impact of plastics aging.

Research of Ferric Ion Regulation on a Polyimide/C-MXene Microcellular Composite Film.

This paper established a new kind of polyimide/C-MXene composite films with a microcellular structure for electromagnetic interference shielding through solution mixing and liquid phase separation methods. Polyimide was used as the resin material, Ti3C2Tx MXene was used as the electromagnetic wave-shielding medium, l-citrulline was used as the surface modification agent, ferric trichloride (especially the ferric ion) was used as the cross-linking agent between the polyimide and modified C-MXene, and a microcell was used as the shielding structure. By adjusting the content of ferric ions, the foam structure, mechanical properties, thermal conductivity, and electromagnetic interference shielding efficiency of the polyimide/C-MXene microcellular composite film could be controlled. The higher the ferric ion content, the smaller the foam size and the higher the electromagnetic interference shielding efficiency. With increasing ferric ion content, the tensile strength and Young's modulus appeared to first increase and then decrease; when the ferric ion content was 0.8 wt %, the tensile strength and Young's modulus reached their maximum values, which were 10.06 and 325.29 MPa, respectively. In addition, with increasing ferric ion content, the thermal insulation showed first decreasing and then increasing tendency; the lowest thermal conductivity was 0.17 W/(m·K) when the ferric ion content was 0.8 wt %.

Using 3.0 eV Large Bandgap Conjugated Polymer as Host Donor to Construct Ternary Semi-Transparent Polymer Solar Cells: Increased Average Visible Transmittance and Modified Color Temperature.

Although optical engineering strategy has been utilized to optimize average visible transmittance (AVT) of semi-transparent organic solar cells (ST-OSCs), judicious selection of active layer materials should be more direct and basic. Herein, an efficient ternary active layer is constructed with a wide bandgap (3.0 eV) fluorescent polymer FC-S1 as host donor, a middle bandgap polymer PM6 as guest donor, and a narrow bandgap non-fullerene Y6-BO as acceptor. Using FC-S1 as the host donor can allow more visible photons to penetrate the device. In the absence of optical engineering, the ternary ST-OSC with FC-S1:PM6:Y6-BO = 1:0.3:1.5 active layer of 30 nm thickness displays a much higher AVT of 49.28% than that of 32.34% for a PM6:Y6-BO = 1.3:1.5 based binary ST-OSC. The ternary ST-OSC provides a good power conversion efficiency of 6.01%, only slightly lower than 7.15% for the binary ST-OSC. The ternary ST-OSC also demonstrates a color rendering index (CRI) of 87 and a correlated color temperature (CCT) of 6916 K, all better than CRI of 80 and CCT of 9022 K for the binary ST-OSC. Moreover, the backbone of FC-S1 is mainly composed by fluorene and carbazole, two easily-accessible aromatic rings, which would meet low-cost concern of ST-OSCs.

Wood-Derived Composites with High Performance for Thermal Management Applications.

Fabricating advanced polymer composites with remarkable mechanical and thermal conductivity performances is desirable for developing advanced devices and equipment. In this study, a novel strategy to prepare anisotropic wood-based scaffolds with a naturally aligned microchannel structure from balsa wood is demonstrated. The wood microchannels were coated with polydopamine-surface-modified small graphene oxide (PGO) nanosheets via assembly. The highly aligned porous microstructures, with thin wood cell walls and large voids along the cellulose microchannels, allow polymers to enter, resulting in the fabrication of the wood-polymer nanocomposite. The tensile stiffness and strength of the resulting nanocomposite reach 8.10 GPa and 90.3 MPa with a toughness of 5.0 MJ m-3. The thermal conductivity of the nanocomposite is improved significantly by coating a PGO layer onto the wood scaffolds. The nanocomposite exhibits not only ultrahigh thermal conductivity (in-plane about 5.5 W m-1 K-1 and through-plane about 2.1 W m-1 K-1) but also satisfactory electrical insulation (volume resistivity of about 1015 Ω·cm). Therefore, the results provide a strategy to fabricate thermal management materials with excellent mechanical properties.

Optimizing the dynamic and thermodynamic properties of hybridization in DNA-mediated nanoparticle self-assembly.

DNA-directed nanoparticle (DNA-NP) systems provide various applications in sensing, medical diagnosis, data storage, plasmonics and photovoltaics. Bonding probability and melting properties are helpful to evaluate the selectivity, thermostability and thermosensitivity of these applications. We investigated the influence of temperature, nanoparticle size, DNA chain length and surface grafting density of DNA on one nanoparticle on the DNA dynamic hybridization percentage and melting properties of DNA-NP assembly systems by molecular dynamics simulation. The high degree of consistency of free energy estimations for DNA hybridization via our theoretical deduction and the nearest-neighbor rule generally used in experiments validates reasonably our DNA model. The melting temperature and thermosensitivity parameter are determined by the sigmoidal melting curves based on hybridization percentage versus temperature. The results indicated that the hybridization percentage presents a downward trend with increasing temperature and nanoparticle size. Applications based on DNA-NP systems with bigger nanoparticle size, such as DNA probes, have better selectivity, thermostability and thermosensitivity. There exist optimal DNA chain length and surface grafting density where the hybridization percentage reaches the maximal value. The melting temperature reaches a maximum at the point of optimal grafting density, while the thermosensitivity parameter presents an upward trend with the increase of grafting density. Several physical quantities consisting of the radial density function, root mean square end-to-end distance, contact distance parameter and effective volume fraction are used to analyse DNA chain conformations and DNA-NP packing in the assembly process. Our findings provide the theoretical basis for the improvement and optimization of applications based on DNA-NP systems.

Androgen receptor signalling impairs docetaxel efficacy in castration-resistant prostate cancer.

Androgen receptor (AR) signalling drives neoplastic growth and therapy resistance in prostate cancer. Recent clinical data show that docetaxel combined with androgen deprivation therapy improves outcome in hormone-sensitive disease. We studied whether testosterone and AR signalling interferes with docetaxel treatment efficacy in castration-resistant prostate cancer (CRPC). We found that testosterone supplementation significantly impaired docetaxel tumour accumulation in a CRPC model, resulting in decreased tubulin stabilisation and antitumour activity. Furthermore, testosterone competed with docetaxel for uptake by the drug transporter OATP1B3. Irrespective of docetaxel-induced tubulin stabilisation, AR signalling by testosterone counteracted docetaxel efficacy. AR-pathway activation could also reverse long-term tumour regression by docetaxel treatment in vivo. These results indicate that to optimise docetaxel efficacy, androgen levels and AR signalling need to be suppressed. This study lends evidence for continued maximum suppression of AR signalling by combining targeted therapeutics with docetaxel in CRPC.

Role of Oatp2b1 in Drug Absorption and Drug-Drug Interactions.

The organic anion transporting polypeptide (OATP)2B1 is localized on the basolateral membrane of hepatocytes and is expressed in enterocytes. Based on its distribution pattern and functional similarity to OATP1B-type transporters, OATP2B1 might have a role in the absorption and disposition of a range of xenobiotics. Although several prescription drugs, including hydroxymethylglutaryl-coenzyme A-CoA reductase inhibitors (statins) such as fluvastatin, are OATP2B1 substrates in vitro, evidence supporting the in vivo relevance of this transporter remains limited, and most has relied on substrate-inhibitor interactions resulting in altered pharmacokinetic properties of the victim drugs. To address this knowledge deficit, we developed and characterized an Oatp2b1-deficient mouse model and evaluated the impact of this transporter on the absorption and disposition of fluvastatin. Consistent with the intestinal localization of Oatp2b1, we found that the genetic deletion or pharmacological inhibition of Oatp2b1 was associated with decreased absorption of fluvastatin by 2- to 3-fold. The availability of a viable Oatp2b1-deficient mouse model provides an opportunity to unequivocally determine the contribution of this transporter to the absorption and drug-drug interaction potential of drugs. SIGNIFICANCE STATEMENT: The current investigation suggests that mice deficient in Oatp2b1 provide a valuable tool to study the in vivo importance of this transporter. In addition, our studies have identified novel potent inhibitors of OATP2B1 among the class of tyrosine kinase inhibitors, a rapidly expanding class of drugs used in various therapeutic areas that may cause drug-drug interactions with OATP2B1 substrates.

Exposure to diisononyl phthalate promotes atopic march by activating of NF-κB and p38 MAPK.

What factors and underlying mechanisms influence the occurrence of the atopic march remain unclear. Recent studies suggest that exposure to diisononyl phthalate (DINP) might be associated with the occurrence of atopic dermatitis (AD) and asthma. However, little is known about the role of DINP exposure in the atopic march. In this study, we investigated the effect of DINP exposure on the progression from AD to asthma, and explored the potential mechanisms. We built an atopic march mouse model from AD to asthma, by exposure to DINP and sensitization with OVA. Pyrrolidine dithiocarbamate and SB203580 were used to block NF-κB and p38 MAPK respectively, to explore the possible molecular mechanisms. The data showed that DINP aggravated airway remodeling and airway hyperresponsiveness (AhR) in the progression from AD to asthma, induced a sharp increase in IL-33, IgE, Th2 and Th17 cytokines, and resulted in an increase in the expression of thymic stromal lymphopoietin (TSLP) and in the number of inflammatory cells. Blocking NF-κB inhibited AD-like lesions, and the production of IL-33 and TSLP in the progression of AD, while alleviating airway remodeling, AhR, and the expression of Th2 and Th17 cytokines in both the progression of AD and the asthmatic phenotype. Blocking p38 MAPK in the progression of asthma, inhibited airway remodeling, AhR, and the expression of Th2 and Th17 cytokines. The results demonstrated that exposure to DINP enhanced the immune response to memory CD4+ T helper cells through the NF-κB and p38 MAPK signaling pathways, leading to an aggravation of the atopic march.

Self-Standing Hydrogels Composed of Conducting Polymers for All-Hydrogel-State Supercapacitors.

Conducting polymer hydrogels that are capable of contacting with electrolytes at the molecular level, represent an important electrode material. However, the fabrication of self-standing hydrogels merely composed of conducting polymers is still challenging owing to the absence of reliable methods. Herein, a novel and facile macromolecular interaction assisted route is reported to fabricate self-standing hydrogels consisting of polyaniline (PANi: providing high electrochemical activity) and poly(3,4-ethylenedioxythiophene) (PEDOT: enabling high electronic conductivity). Owing to the synergistic effect between them, the self-standing hydrogels possess good mechanical properties and electronic/electrochemical performances, making them an excellent potential electrode for solid-state energy storage devices. A proof-of-concept all-hydrogel-state supercapacitor is fabricated, which exhibits a high areal capacitance of 808.2 mF cm-2 , and a high energy density of 0.63 mWh cm-3 at high power density of 28.42 mW cm-3 , superior to many recently reported conducting polymer hydrogels based supercapacitors. This study demonstrates a novel promising strategy to fabricate self-standing conducting polymer hydrogels.

Exposure to polystyrene microplastics causes reproductive toxicity through oxidative stress and activation of the p38 MAPK signaling pathway.

Microplastics (MP) are receiving increased attention as a harmful environmental pollutant, however information on the reproduction toxicity of MP in terrestrial animals, especially mammals, is limited. In this experiment, we investigated the impact of polystyrene microplastics (micro-PS) on the reproductive system of male mice. Healthy Balb/c mice were exposed to saline or to different doses of micro-PS for 6 weeks. The results showed that micro-PS exposure resulted in a significant decrease in the number and motility of sperm, and a significant increase in sperm deformity rate. We also detected a decrease in the activity of the sperm metabolism-related enzymes, succinate dehydrogenase (SDH) and lactate dehydrogenase (LDH), and a decrease in the serum testosterone content in the micro-PS exposure group. We found that micro-PS exposure caused oxidative stress and activated JNK and p38 MAPK. In addition, we found that when N-acetylcysteine (NAC) scavenges ROS, and when the p38 MAPK-specific inhibitor SB203580 inhibits p38MAPK, the micro-PS-induced sperm damage is alleviated and testosterone secretion improves. In conclusion, our findings suggest that micro-PS induces reproductive toxicity in mice through oxidative stress and activation of the p38 MAPK signaling pathways.

Injectable and Near-Infrared-Responsive Hydrogels Encapsulating Dopamine-Stabilized Gold Nanorods with Long Photothermal Activity Controlled for Tumor Therapy.

Gold nanorods (AuNRs) are confirmed to have excellent and repeated photothermal properties under near-infrared (NIR)-light irradiation above 780 nm. However, AuNRs easily leaked out from local pathological tissues and circulated in the body, reducing photothermal therapy (PTT) efficacy. By complexing AuNRs with a scaffold via interactions, AuNRs might be dispersed in the scaffold and fixed in the tumor site. Thus, based on the mussel-mimetic adhesion concept, AuNRs were designed to be coated with polydopamine (PDA), and then the prepared polydopamine-coated AuNRs (AuNR-PDA) were incorporated into a thermosensitive injectable hydrogel composed of ß-glycerophosphate-bound chitosan (CGP) and dopamine-modified alginate (Alg-DA) efficiently. Due to the strong interactions between PDA and polymers, AuNR-PDA could be immobilized stably and evenly into the obtained CGP/Alg-DA/AuNR composite hydrogel, which can avoid overheating locally or leaking out. The sol-gel transition temperature of the composite hydrogel was adjusted to the body temperature at around 37 °C to be conveniently injectable in vivo. With NIR irradiation at 808 nm of wavelength, the composite hydrogel was locally heated quickly to over 50 °C depending on controlling the irradiation powers and times. Moreover, the in vitro cytotoxicity test of the composite hydrogel showed good biocompatibility to normal cells but obvious suppression to tumor cells' growth under multiple times of photothermal therapy. Furthermore, the in vivo antitumor test demonstrated the obvious suppression to tumor growth of the CGP/Alg-DA/AuNR composite hydrogel under multiple PTTs. Therefore, the injectable CGP/Alg-DA/AuNR hydrogel could be a promising candidate for the long-term repeated photothermal treatment of tumors.

Repeated exposure to temperature variation exacerbates airway inflammation through TRPA1 in a mouse model of asthma.

BACKGROUND AND OBJECTIVE: Studies from epidemiology suggest that ambient temperature is one of the underlying triggers and potential causes of asthma. The aim of this study was to examine the impact and the molecular mechanism of temperature-invoked airway inflammation using an experimental model of asthma in BALB/c mice. METHODS: Mice were exposed to different temperature conditions (steady 26°C, 26°C/18°C cycle, 26°C/10°C cycle) and received sensitization and challenge of ovalbumin (OVA) during a 21-day period. HC030031, a selective transient receptor potential A1 (TRPA1) channel blocker, was used to investigate the underlying mechanism of TRPA1 in 'asthmatic' airways. After the final OVA challenge, in vivo lung function was measured, and bronchoalveolar lavage fluid (BALF) and pulmonary inflammation were assessed. RESULTS: The temperature variations, especially the largest temperature difference (16°C), exacerbated airway inflammation in OVA-induced mice, increasing the levels of serum total-IgE (immunoglobulin E) and IgG1, inflammatory cells and cytokines in BALF. Analysis of histopathological changes and lung function verified that repeated exposure to very cold and changed temperatures aggravated airway hyperresponsiveness (AHR). Significant upregulation of TRPA1 expression was revealed by immunohistochemistry in the presence of the largest temperature variation (26°C/10°C cycle), while administration of HC030031 successfully inhibited TRPA1 expression, thus attenuating the asthma-like pathological features. CONCLUSION: Repeated exposure to temperature variation exacerbated experimental 'asthma' and TRPA1 mediated this temperature-dependent inflammatory effect.

Comparing the effects of diethylhexyl phthalate and dibutyl phthalate exposure on hypertension in mice.

Epidemiological studies have shown that high molecular weight phthalates (HMW) such as diethylhexyl phthalate (DEHP), are associated with hypertension in humans, while low molecular weight phthalates (LMW) such as dibutyl phthalate (DBP), have hardly any impact on the elevation of blood pressure. However, the molecular mechanisms responsible for this difference are not completely understood. In this experiment, mice were exposed to 0.1/1/10 mg/kg/day DEHP and 0.1/1/10 mg/kg/day DBP for 6 weeks, and their blood pressure was monitored using the tail pressure method. The results showed that exposure to DEHP dosages of 1 or 10 mg/kg/day resulted in a sharp increase in blood pressure, while exposure to DBP did not induce any significant changes in blood pressure. Investigating the renin-angiotensin-aldosterone system (RAAS) and NO pathway in mice exposed to DEHP, we found that levels of angiotensin-converting enzyme (ACE) and angiotensin II (AngII) increased with increasing exposure to DEHP, and the expression of nitric oxide synthase (eNOS) and the level of NO decreased. Treatment with ACE inhibitor (ACEI) to block the ACE pathway inhibited the enhancement of RAAS expression, inhibited the increase in blood pressure, and inhibited the decrease in NO levels induced by DEHP. However, the expression of ACE, AngII, AT1R, and eNOS in the DBP treatment groups showed no significant changes. When examining estradiol in vivo, we found that exposure to DBP resulted in a significant increase in the level of estradiol, while exposure to DEHP did not lead to a significant change. When ICI182780 was used to block the estradiol receptors, any increase in the level of NO induced by DBP exposure, was inhibited. These results indicate that exposure to DEHP induces an increase in mouse blood pressure through RAAS, and the different effects of DEHP and DBP on blood pressure are partly due to the different estradiol levels induced by DEHP and DBP.

Exposure to formaldehyde and diisononyl phthalate exacerbate neuroinflammation through NF-κB activation in a mouse asthma model.

Diisononyl phthalate (DINP) and formaldehyde both are associated with asthma and allergies. However, it is unclear about the adverse effect of DINP and formaldehyde exposure on the brain for asthma patients. Here, we determined the effect of DINP and/or formaldehyde exposure on neuroinflammation in brain by a murine asthma model and investigated the underlying mechanisms. Mice were exposed to formaldehyde and/or DINP and sensitization with ovalbumin. The results show that exposure to formaldehyde and/or DINP not only exacerbated allergic asthma-like symptoms, but also promoted neuroinflammation in brain. The incrassation of the airway wall and exacerbation of neuroinflammation were more obviously when mice were subjected to a combined exposure to DINP and formaldehyde. Exposure to DINP and/or formaldehyde enhances oxidative stress and the activation of NF-κB in the prefrontal cortex of mouse asthma model. Exposure to DINP and/or formaldehyde also induced an increase in IL-1ß, IL-17, and NGF. Blocking oxidative stress by administering melatonin or inhibiting NF-κB activation by treatment with Dehydroxymethylepoxyquinomicin effectively prevented increasing the levels IL-1ß, IL-17 and nerve growth factor. The data indicated that DINP and/or formaldehyde exposure promoted neuroinflammation in the brain through enhanced oxidative stress and activation of NF-κB in a mouse asthma model.

Superior Performance of Polyurethane Based on Natural Melanin Nanoparticles.

Melanin, a kind of well-known multifunctional biomacromolecules that are widely distributed in natural sources. In this work, polyurethane (PU)/melanin nanocomposites with enhanced tensile strength and toughness were successfully fabricated via in situ polymerization. It was found that the tensile strength (σ), elongation-at-break (εmax), and toughness (W) were improved from 5.6 MPa, 770%, and 33 MJ/m3 for PU to 51.5 MPa, 1880%, and 413 MJ/m3 for PU/melanin (2 wt %) nanocomposite, respectively. Micromorphology indicated that individualized melanin nanoparticles were specifically linked to the hard domains of PU chains and fine dispersed in matrix. FTIR, DSC, and AFM results suggested melanin induced an improvement in degree of phase separation, which resulted in remarkable enhancements in mechanical properties of PU. However, with further increasing content of melanin, a relatively large-scale phase separation was formed and led to a decrease in mechanical properties of PU. In addition, interactions between melanin and hard segments of PU were increased, leading to a higher TgHS. Moreover, the dynamic mechanical properties and rheological behavior of PU/melanin nanocomposites were further investigated.

Highly exposed surface area of {001} facets dominated BiOBr nanosheets with enhanced visible light photocatalytic activity.

Two groups of BiOBr nanosheets with different sizes and similar exposure percentages of {001} facets were selectively synthesized by simple hydrothermal methods. The obtained samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and UV-vis diffuse reflectance spectroscopy (DRS). The photocatalytic activity was estimated from the degradation of organic pollutants under visible-light irradiation. The results indicated that BiOBr nanosheets with similar exposure percentages of {001} facets but smaller sizes exhibited higher photocatalytic activity. Furthermore, the effects of the size, including the thickness and length, of BiOBr nanosheets were also studied. The results showed that the impact of thickness was more significant than that of length. It was found that reducing the thickness of BiOBr nanosheets can significantly increase the exposed surface areas of {001} facets (S{001}), but not necessarily the exposure percentage of {001} facets. Moreover, in our experiment, the photocatalytic activity of BiOBr nanosheets increased linearly with an increase in S{001} in the range of 0.022 to 0.111 nm(-1). Therefore, the photocatalytic activity of BiOBr nanosheets depended on the exposed surface areas of {001} facets rather than the exposure percentage of {001} facets. The enhancement of the photocatalytic activity of ultrathin BiOBr nanosheets with large exposed surface areas of {001} facets can be mainly ascribed to their enhanced absorption of visible light and improved separation efficiency of charge carriers.

The toxic effects of indoor atmospheric fine particulate matter collected from allergic and non-allergic families in Wuhan on mouse peritoneal macrophages.

Recent studies have shown that fine particulate matter (PM2.5) is associated with multiple adverse health outcomes and PM2.5-induced oxidative stress is now commonly known as a proposed mechanism of PM2.5-mediated toxicity. However, the association between allergic symptoms in children and exposure to PM2.5 has not been fully elucidated, particularly the role of PM2.5 on the indoor environment involved in allergy or non-allergy is unknown. The aim of the present study was to explore whether indoor PM2.5 from the homes of children with allergic symptoms had more increased risks of allergy than that of healthy ones and then compare the toxicity and inflammatory response of them. In this study, indoor PM2.5 was collected from the homes of schoolchildren with allergic symptoms and those of healthy ones respectively, and components of PM2.5 were analyzed. PM2.5-mediated oxidative damage and inflammatory response were further evaluated in mouse peritoneal macrophages based on its effects on the levels of reactive oxygen species accumulation, lipid peroxidation, DNA damage or cytokine production. It seems that oxidative stress may contribute to PM2.5-induced toxicity, and PM2.5 from the allergic indoor environment produced more serious toxic effects and an inflammatory response on mouse peritoneal macrophages than that from a non-allergic indoor environment.

Rapid Stereocomplexation between Enantiomeric Comb-Shaped Cellulose-g-poly(L-lactide) Nanohybrids and Poly(D-lactide) from the Melt.

In this work we report the in situ preparation of fully biobased stereocomplex poly(lactide) (SC-PLA) nanocomposites grafted onto nanocrystalline cellulose (NCC). The stereocomplexation rate by compounding high-molar-mass poly(D-lactide) (PDLA) with comb-like NCC grafted poly(L-lactide) is rather high in comparison with mixtures of PDLA and PLLA. The rapid stereocomplexation was evidenced by a high stereocomplexation temperature (Tc-sc = 145 °C) and a high SC crystallinity (Xc-sc = 38%) upon fast cooling (50 °C/min) from the melt (250 °C for 2 min), which are higher than currently reported values. Moreover, the half-life crystallization time (175-190 °C) of the SC-PLA was shortened by 84-92% in comparison with the PDLA/PLLA blends. The high(er) stereocomplexation rate and the melt stability of the SC in the nanocomposites were ascribed to the nucleation effect of the chemically bonded NCC and the "memory effect" of molecular pairs in the stereocomplex melt because of the confined freedom of the grafted PLLA chains.

Fabrication of novel chemosensors composed of rhodamine derivative for the detection of ferric ion and mechanism studies on the interaction between sensor and ferric ion.

Although many rhodamine based fluorescence sensors were reported to detect metal ions with high sensitivity and selectivity, there are very few reports available to study the mechanisms of detection and the interaction between probe and metal ions. This paper aims to detect ferric ions by novel fluorescence chemosensors and study the mechanisms in detail. A novel probe AD-MAH-RhB was designed and synthesized from rhodamine B (RhB), adamantyl (AD), ethylene diamine and maleic anhydride (MAH). AD-MAH-RhB could detect Fe(3+) in aqueous solutions. The mechanism was explored by the HSAB principle, FTIR and mass spectra. The results suggested that Fe(3+) bound with amine and oxygen atoms in AD-MAH-RhB to form a complex composed of a 2 : 1 stoichiometry of Fe(3+) and the probe. Moreover, computational simulations were employed to further investigate the detection mechanism. The calculated results showed that Fe(3+) could conjugate with AD-MAH-RhB probe to form a stable complex, which was induced by synergetic effects of the suitable space and distance of van der Waals forces. However, Hg(2+) was found to disturb this detection and form a complex with 1 : 2 stoichiometry of Hg(2+) and AD-MAH-RhB. Then, another probe, ß-cyclodextrin modified polymaleic anhydride (PMAH-CD) including AD-MAH-RhB (PMAH-CD/AD-MAH-RhB) was fabricated by inclusion interaction between CD and AD. PMAH-CD@AD-MAH-RhB showed high selectivity and sensitivity to Fe(3+) in the aqueous solution by eliminating the interruption of Hg(2+) possibly due to the high hydrogen interaction among the probes to inhibit the stable form complex with Hg(2+).