Effect of Thermal Aging on Mechanical Properties and Morphology of GF/PBT Composites.

The effects of thermal aging at 85~145 °C in air on the tensile and flexural mechanical properties of 20% glass fiber (GF)-reinforced commercial grade polybutylene terephthalate (PBT) composites were studied. The results showed that as the aging temperature increased, the tensile and flexural strength of the GF/PBT composites significantly decreased. However, the elastic modulus of the composites was almost independent of aging. As the aging temperature increased, the separation between GF and the PBT matrix became more pronounced, and the fibers exposed on the surface of the matrix became clearer and smoother, indicating a decrease in interfacial adhesion between the PBT matrix and GF. The reason for this decrease in strength and brittle fracture of composites is the interface damage between the GF and PBT matrix caused by the difference in their thermal expansion coefficients during thermal aging.

Guided multi-scale refinement network for camouflaged object detection.

The purpose of camouflaged object detection (COD) is to identify the hidden camouflaged object in an input image. Compared with other binary segmentation tasks like salient object detection, COD needs to deal with more complex scenes, such as low contrast, similar foreground and background. In this work, we proposed a novel guided multi-scale refinement network for COD. Specifically, we first design a global perception module for coarse localization by stacking multi-scale residual block on the top of the backbone in a recurrent manner. Then, we propose the guided multi-scale refinement module to refine such initial prediction progressively, which is combined with multi-level side-output features in a prediction-to-feature fusion strategy. By plugging into side-output features for multi-scale guidance, the missing object parts and false detection can be well remedied. Experimental results show that our proposed network can more accurately locate the camouflaged object and salient object with sharpened details than existing state-of-the-art approaches. In addition, our model is also very efficient and compact, which enables potential real-world applications.

Regulation of TRPV1 channel in monosodium urate-induced gouty arthritis in mice.

OBJECTIVE: The transient receptor potential vanilloid subtype 1 (TRPV1) channel is considered to play an important regulatory role in the process of pain. The purpose of this study is to observe the change characteristics of TRPV1 channel in MSU-induced gouty arthritis and to find a new target for clinical treatment of gout pain. METHODS: Acute gouty arthritis was induced by injection of monosodium urate (MSU) crystals into the ankle joint of mice. The swelling degree was evaluated by measuring the circumference of the ankle joint. Mechanical hyperalgesia was conducted using the electronic von Frey. Calcium fluorescence and TRPV1 current were recorded by applying laser scanning confocal microscope and patch clamp in dorsal root ganglion (DRG) neurons, respectively. RESULTS: MSU treatment resulted in significant inflammatory response and mechanical hyperalgesia. The peak swelling degree appeared at 12 h, and the minimum pain threshold appeared at 8 h after MSU treatment. The fluorescence intensity of capsaicin-induced calcium response and TRPV1 current were increased in DRG cells from MSU-treated mice. The number of cells that increased calcium response after MSU treatment was mainly distributed in small-diameter DRG cells. However, the action potential was not significantly changed in small-diameter DRG cells after MSU treatment. CONCLUSIONS: These findings identified an important role of TRPV1 in mediating mechanical hyperalgesia in MSU-induced gouty arthritis and further suggest that TRPV1 can be regarded as a potential new target for the clinical treatment of gouty arthritis.

Magnolol attenuates inflammatory pain by inhibiting sodium currents in mouse dorsal root ganglion neurons.

Voltage-gated sodium channels are currently recognized as one of the targets of analgesics. Magnolol (Mag), an active component isolated from Magnolia officinalis, has been reported to exhibit analgesic effects. The objective of this study was to investigate whether the analgesic effect of Mag was associated with blocking Na+ channels. Inflammatory pain was induced by the injection of carrageenan into the hind paw of mice. Mag was administered orally. Mechanical hyperanalgesia was evaluated by using von Frey filaments. Na+ currents and neuronal excitability in acutely isolated mouse dorsal root ganglion (DRG) neurons were recorded with the whole-cell patch clamp technique. Results showed that Mag (10 ~ 40 mg/kg) dose-dependently inhibited the paw edema and reduced mechanical pain in the inflammatory animal model. Injection of carrageenan significantly increased the amplitudes of TTX-sensitive and TTX-resistant Na+ currents. Compared with the carrageenan group, Mag inhibited the upregulation of two types of Na+ currents induced by carrageenan in a dose-dependent manner. Mag 40 mg/kg shifted the inactivation curves of two types of Na+ currents to hyperpolarization and returned to normal animal level without changing their activation curves. Mag 40 mg/kg significantly reduced the percentage of cells firing multiple spikes and inhibited the neuronal hyperexcitability induced by carrageenan. Our data suggest that the analgesic effect of Mag may be associated with a decreased neuronal excitability by blocking Na+ current.

Modulations of Nav1.8 and Nav1.9 Channels in Monosodium Urate-Induced Gouty Arthritis in Mice.

The aim of the present study was to observe the changes of TTX-R, Nav1.8, and Nav1.9 Na+ currents in MSU-induced gouty arthritis mice, and to explore the possibility of Nav1.8 and Nav1.9 channels as potential targets for gout pain treatment. Acute gouty arthritis was induced by monosodium urate (MSU) in mice. Swelling degree was evaluated by measuring the circumference of the ankle joint. Mechanical allodynia was assessed by applying the electronic von Frey. Na+ currents were recorded by patch-clamp techniques in acute isolated dorsal root ganglion (DRG) neurons. MSU treatment significantly increased the swelling degree of ankle joint and decreased the mechanical pain threshold. The amplitude of TTX-R Na+ current was significantly increased and reached its peak on the 4th day after injection of MSU. For TTX-R Na+ channel subunits, Nav1.8 current density was significantly increased, but Nav1.9 current density was markedly decreased after MSU treatment. MSU treatment shifted the steady-state activation curves of TTX-R Na+ channel, Nav1.8 and Nav1.9 channels, and the inactivation curves of TTX-R Na+ channel and Nav1.8 channels to the depolarizing direction, but did not affect the inactivation curve of Nav1.9 channel. Compared with the normal group, the recovery of Nav1.8 channel was faster, while that of Nav1.9 channel was slower. The recovery of TTX-R Na+ channel remained unchanged after MSU treatment. Additionally, MSU treatment increased DRG neurons excitability by reducing action potential threshold. Nav1.8 channel, not Nav1.9 channel, may be involved in MSU-induced gout pain by increasing nerve excitability.

Aprepitant Inhibits JNK and p38/MAPK to Attenuate Inflammation and Suppresses Inflammatory Pain.

Substance P contributes to the pathogenesis of pain by acting on NK-1R, specialized sensory neurons that detect noxious stimuli. Aprepitant, an antagonist of NK-1R, is widely used to treat chemotherapy-induced nausea and vomiting. In this study, we used LPS-stimulated BV-2 microglia cell line and animal models of inflammatory pain to explore the analgesic effect of aprepitant on inflammatory pain and its underlying mechanism. The excitability of DRG neurons were measured using whole-cell patch-clamp recordings. The behavioral tests were measured and the morphological changes on inflamed paw sections were determined by HE staining. Changes in the expressions of cytokine were measured by using real-time quantitative PCR analysis and ELISA method. Immunofluorescence and western blotting were used to detect the microglia activation and MAPK. Aprepitant treatment significantly inhibited the excitability of DRG neurons. The pain behavior and the paw tissues inflammatory damage were significantly relived after the administration of aprepitant compared to formalin group. Aprepitant significantly suppressed the activation of microglia, phosphorylation of JNK and p38 MAPK, as well as the mRNA and protein expressions of MCP-1, TNF-α, IL-6, and IL-1ß, in vivo and in vitro. The LPS-induced over-translocation into nucleus of NF-κBp65 was down-regulated following aprepitant treatment in BV-2 cells. The present study suggests that aprepitant attenuates inflammatory pain in mice via suppressing the phosphorylation of JNK and p38, and inhibiting the NF-κB signaling pathway.

Hydrophilic/Hydrophobic Heterogeneity Anti-Biofouling Hydrogels with Well-Regulated Rehydration.

Hydrogels, as a representative of soft and biocompatible materials, have been widely used in biosensors, biomedical devices, soft robotics, and the marine industry. However, the ir-recoverability of hydrogels after dehydration, which causes the loss of original mechanical, optical, and wetting properties, has severely restricted their practical applications. At present, this critical challenge of maintaining hydrogels' accurate character has attracted less attention. To address this, here we report a hydrogel based on synergistic effects to achieve both well-regulated rehydration and deswelling properties. The hydrogel after dehydration can quickly restore its original state both on the macro- and microscale. In addition, the hydrogel has excellent mechanical stability after several dehydration-rehydration cycles. All of these properties offer a possibility of water condition endurance and increase the service life. The robust property is attributed to the hydrophilic-hydrophobic and ionic interactions induced by the synergy of hydrophilic/oleophilic heteronetworks. Moreover, zwitterionic segments as hydrophilic network play a vital role in fabricating anti-biofouling hydrogels. The durable and reusable hydrogel may have promising applications for biomedical materials, flexible devices, and the marine industry.