Exploring the Impact of Visual Heat Conduction Paths on Thermal Conductivity of Polymer Composites and the Practical Applications.

The theory of heat conduction paths has been widely recognized and widely studied in the research about the thermal conductivity of thermal conductive polymer composites at present. Encapsulating polymer pellets with thermally conductive fillers and processing them into thermally conductive polymer composites is a simple and effective method for constructing heat conduction paths. It is meaningful to investigate the related heat conduction mechanism of this method. Otherwise, this approach can significantly preserve the performance of the polymer substrate, making it highly valuable for practical material applications. In this work, polyethylene-octene elastomer (POE) pellets were encapsulated with thermal conductive fillers by physical absorption. Subsequently, the composite films containing heat conduction paths were fabricated using the encapsulated POE pellets through a heating press. Alumina (Al2O3), boron nitride (BN), and alumina/boron nitride hybrid (Al2O3/BN) fillers were used to prepare Al2O3@POE, BN@POE, and BN/Al2O3@POE composite films to investigate the influence of filler shapes on heat conduction path construction. The influence of the constitute and density of heat conduction paths on the thermal conductivity of composite films was analyzed by infrared thermal imaging, finite element analysis, and thermal resistance theory in detail. Owing to the reserved good adhesion and flexibility of the POE substrate, the composite films could be directly used as thermal interface materials for chip cooling, which presented a good heat dissipation effect. Furthermore, a series of integrated composite materials were prepared by the combination of encapsulated pellets with various functional films (copper foil, aluminum foil, and graphite sheet) through a one-pot heating press, exhibiting a good electromagnetic shielding effect. The performance of the composites and the corresponding preparation method demonstrate the strong significance of this research for practical applications.

Core-Shell Gel Nanofiber Scaffolds Constructed by Microfluidic Spinning toward Wound Repair and Tissue Regeneration.

Growing demand for wound care resulting from the increasing chronic diseases and trauma brings intense pressure to global medical health service system. Artificial skin provides mechanical and microenvironmental support for wound, which is crucial in wound healing and tissue regeneration. However, challenges still remain in the clinical application of artificial skin since the lack of the synergy effect of necessary performance. In this study, a multi-functional artificial skin is fabricated through microfluidic spinning technology by using core-shell gel nanofiber scaffolds (NFSs). This strategy can precisely manipulate the microstructure of artificial skin under microscale. The as-prepared artificial skin demonstrates superior characteristics including surface wettability, breathability, high mechanical strength, strain sensitivity, biocompatibility and biodegradability. Notably, this artificial skin has the capability to deliver medications in a controlled and sustained manner, thereby accelerating the wound healing process. This innovative approach paves the way for the development of a new generation of artificial skin and introduces a novel concept for the structural design of the unique core-shell gel NFSs.

A Phase Inversion-Based Microfluidic Fabrication of Helical Microfibers towards Versatile Artificial Abdominal Skin.

Microfluidic spinning technology (MST), incorporating microfluidics with chemical reactions, has gained considerable interest for constructing anisotropic advanced microfibers, especially helical microfibers. However, these efforts suffer from the limited material choices, restricting their applications. Here, a new phase inversion-based microfluidic spinning (PIMS) method is proposed for producing helical microfibers. This method undergoes a physicochemical phase inversion process, which is capable of efficiently manufacturing strong (tensile stress of more than 25 MPa), stretchable, flexible and biocompatible helical microfibers. The helical microfibers can be used to fabricate bi-oriented stretchable artificial abdominal skin, preventing incisional hernia formation and promoting the wound healing without conglutination. This research not only offers a universal approach to design helical microfibers but also provides a new insight into artificial skin.

Decentralized Adaptive Command Filtered Neural Tracking Control of Large-Scale Nonlinear Systems: An Almost Fast Finite-Time Framework.

In this article, a decentralized adaptive finite-time tracking control scheme is proposed for a class of nonstrict feedback large-scale nonlinear interconnected systems with disturbances. First, a practical almost fast finite-time stability framework is established for a general nonlinear system, which is then applied to the design of the large-scale system under consideration. By fusing command filter technique and adaptive neural control and introducing two smooth functions, the "singular" and "explosion of complex" problems in the backstepping procedure are circumvented, while the obstacles caused by unknown interconnections are overcome. Moreover, according to the framework of practical almost fast finite-time stability, it is shown that all the closed-loop signals of the large-scale system are almost fast finite-time bounded, and the tracking errors can converge to arbitrarily small residual sets predefined in an almost fast finite time. Finally, a simulation example is presented to demonstrate the effectiveness of the proposed finite-time decentralized control scheme.

Macroscopic Self-Assembly of Gel-Based Microfibers toward Functional Nonwoven Fabrics.

Macroscopic self-assembly has increasingly attracted numerous concerns because of the facile fabrication of complex structures and diversified morphologies. Key challenges still remain to design high-performance building blocks to increase the efficiency and diversity of macroscopic self-assembly. Here, we designed triple noncovalent interactions (carboxyl-Zn2+ coordination, host-guest interactions, and hydrogen bonding interactions) to enhance the interactions between self-healing fibers, constructing multidimensional nonwoven fiber-based fabrics through macroscopic self-assembly without further postprocessing. Profiled from the strong interactions generated from triple noncovalent interactions, ordered two-dimensional plane and three-dimensional spiral gel fabrics were fabricated using polyvinyl pyrrolidone/gel-based fibers as building blocks toward a human motion sensor. Moreover, we demonstrated that the macroscopic self-assembly strategy is universal to construct three-dimensional film-based fabrics toward wound dressing based on the triple noncovalent interactions between two-dimensional films. This macroscopic self-assembly approach provides an alternative strategy to fabricate gel fabrics for various applications.

Microfluidics-Assisted Assembly of Injectable Photonic Hydrogels toward Reflective Cooling.

Development of fast curing and easy modeling of colloidal photonic crystals is highly desirable for various applications. Here, a novel type of injectable photonic hydrogel (IPH) is proposed to achieve self-healable structural color by integrating microfluidics-derived photonic supraballs with supramolecular hydrogels. The supramolecular hydrogel is engineered via incorporating ß-cyclodextrin/poly(2-hydroxypropyl acrylate-co-N-vinylimidazole) (CD/poly(HPA-co-VI)) with methacrylated gelatin (GelMA), and serves as a scaffold for colloidal crystal arrays. The photonic supraballs derived from the microfluidics techniques, exhibit excellent compatibility with the hydrogel scaffolds, leading to enhanced assembly efficiency. By virtue of hydrogen bonds and host-guest interactions, a series of self-healable photonic hydrogels (linear, planar, and spiral assemblies) can be facilely assembled. It is demonstrated that the spherical symmetry of the photonic supraballs endows them with identical optical responses independent of viewing angles. In addition, by taking the advantage of angle independent spectrum characteristics, the IPH presents beneficial effects in reflective cooling, which can achieve up to 17.4 °C in passive solar reflective cooling. The strategy represents an easy-to-perform platform for the construction of IPH, providing novel insights into macroscopic self-assembly toward thermal management applications.

Isoflurane Preconditioning Attenuates Brain Injury Induced by Electromagnetic Pulse via the TLR4/NFκB Signaling Pathway.

Electromagnetic pulse (EMP) is a unique type of electromagnetic radiation, and EMP exposure causes a series of biological effects. The nervous system is sensitive to EMP. We studied the neuroprotective effects of isoflurane preconditioning against EMP exposure and used hematoxylin-eosin staining (HE) to observe the effects of electromagnetic pulse and isoflurane preconditioning on neurons. Inflammatory cytokines were detected by enzyme-linked immunosorbent assay (ELISA). Western blotting was used to detect the expression of caspase-3, CD11b, TLR4, and NFκBp65. We found that after EMP exposure, the number of abnormal neurons had increased, and the expression of caspase-3, CD11b, TLR4, and NFκBp65 had also increased. Isoflurane preconditioning can reverse the above phenomenon. Moreover, we found that isoflurane preconditioning can reduce neuronal apoptosis and improve cognitive impairment induced by EMP. These findings indicate that isoflurane preconditioning can protect neurons in the cerebral cortex from EMP exposure, alleviate the inflammatory reaction and cell apoptosis, and improve cognitive impairment induced by EMP. These effects may occur through the downregulation of the TLR4/NFκB signaling pathway and the inhibition of microglial activation.

Thoracic Endovascular Aortic Repair for Traumatic Thoracic Aortic Injury: A Single-Center Initial Experience.

BACKGROUND: Several publications have documented the technical feasibility and efficacy of stent grafting for aortic injuries. We report short- and mid-term results of thoracic endovascular repair with covered stent grafts for type B blunt thoracic aortic injury. METHODS: We performed a retrospective review of patients who had sustained blunt thoracic aortic injuries. From January 2010 to March 2014, 13 patients (12 men and 1 woman) were admitted and treated in our department for type B thoracic aortic injury. The patients' ages ranged from 19 to 62 years. Traffic accidents were responsible for 10 of the 13 blunt thoracic aortic injuries, and the remainder was caused by blunt trauma from falls. Medical records were examined to identify the clinical outcomes of the procedures, and follow-up computed tomography scans were reviewed to document the efficacy of thoracic endovascular aortic repair. RESULTS: Endovascular stent grafting was technically successful in all cases, and no paraplegia or stroke-like events were reported. No major cardiac, neurologic, or peripheral vascular complications were observed during early or late follow-up. None of the patients died from procedure-related complications. CONCLUSIONS: Our single-center experience demonstrates the feasibility of performing endovascular repair for type B blunt aortic injury. As experience with endovascular surgery accumulates, this method of treatment promises to become the first-choice option for repairing this type of aortic injury, with less associated morbidity and mortality relative to conventional surgical repair.

[A New Calibrated Model of Coal Calorific Value Detection with LIBS].

A set of coal samples were used for laser-induced breakdown spectroscopy (LIBS) experiment to measure the coal calorific value. Traditional channel normalization method didn't consider the physical / chemical mechanism of coal, which would limit the model in precision, accuracy and repeatability. Thus a new calibrated model based on the kinds of the effects of spectral deviation was proposed in this paper. The model selected 19 groups of coal samples, where the random 15 groups were used to establish quantitative analysis model of calorific value while the remaining four for inspection and evaluation. The model based on spectral deviation factors, and the transmission theory combined with the stark broadening formula was used to deduce the absorption effect mechanism and the deviation correction method under the condition of LIBS. The mutual interference between elements and the mechanism of matrix effect were being analyzed while K coefficient method was used to correct mutual interference between the elements in the LIBS. The establishment of numerical model with the electron density, the plasma temperature and the element concentration was used to deeply corrected spectrum deviation caused by matrix effect. Thus taking into consideration of the effect of self-absorption, interfere of inter-elements and matrix effect, the calibration model was established, while R2=0.967, RMSEP=0.49 MJ·kg-1, RMSE=0.45 MJ·kg-1, MRE=2.42%, ARE=1.64%, RSD=5.79% and RSDP=8.10%. Compared with the 0.405, 8.28 MJ·kg-1, 4.14 MJ·kg-1, 22.85%, 52.48%, 18.28% and 32.85% of traditional channel normalized-multiple linear regression method, it demonstrated that the precision and accuracy have been improved significantly and model has good application value.

Development of water quality criteria for phenanthrene and comparison of the sensitivity between native and non-native species.

Phenanthrene (PHE) is a priority polycyclic aromatic hydrocarbon (PAH) which is toxic to aquatic organisms.However, there has been no paper dealing with water quality criteria (WQC) of PHE due to the shortage of toxicity data of different taxonomic levels. In the present study, toxicity data were obtained from 8 acute toxicity tests and 3 chronic toxicity tests using 8 Chinese native aquatic species from different taxonomic levels, and the water quality criteria was derived using 3 methods. Furthermore, differences of species sensitivity distributions (SSDs) between native and non-native species were compared. A criterion maximum concentration of 0.0514 mg/L and a criterion continuous concentration of 0.0186 mg/L were developed according to the US EPA guidelines. Finally, by using risk quotient (RQ) to assess the site-specific ecological risk in Liao River, the results indicated that the PHE might pose no risk to local aquatic species.

Optimal waist circumference cut-off values for identifying metabolic risk factors in middle-aged and elderly subjects in Shandong Province of China.

OBJECTIVE: To study the optimal waist circumference (WC) cut-off values for identifying metabolic risk factors in middle-aged and elderly subjects in Shandong Province of China. METHODS: A total of 2,873 men and 5,559 women were included in this cross-sectional study. Metabolic syndrome (MetS) was diagnosed according to the definition of Chinese Diabetes Society in 2004. The relation between WC and MetS was analyzed by multivariate logistic regression analysis. The optimal WC cut-off values were identified using the area under the ROC curve and the different diagnostic criteria for central obesity were compared. RESULTS: The WC was the risk factor for MetS independent of BMI, blood glucose, blood lipid, and blood pressure. The optimal WC cut-off value was 83.8 cm and 91.1 cm for identifying MetS in women and men, respectively. Compared with 80 cm and 85 cm for women and men, 85 cm and 90 cm had a higher Youden index for identifying all metabolic risk factors and MetS in women and men. CONCLUSION: The appropriate WC cut-off value is 85 cm and 90 cm for identifying central obesity and MetS in women and men in Shandong Province of China.

Spinal changes of a newly isolated neuropeptide endomorphin-2 concomitant with vincristine-induced allodynia.

Chemotherapy-induced neuropathic pain (CNP) is the major dose-limiting factor in cancer chemotherapy. However, the neural mechanisms underlying CNP remain unclear. There is increasing evidence implicating the involvement of spinal endomorphin-2 (EM2) in neuropathic pain. In this study, we used a vincristine-evoked rat CNP model displaying mechanical allodynia and central sensitization, and observed a significant decrease in the expression of spinal EM2 in CNP. Also, while intrathecal administration of exogenous EM2 attenuated allodynia and central sensitization, the mu-opioid receptor antagonist ß-funaltrexamine facilitated these events. We found that the reduction in spinal EM2 was mediated by increased activity of dipeptidylpeptidase IV, possibly as a consequence of chemotherapy-induced oxidative stress. Taken together, our findings suggest that a decrease in spinal EM2 expression causes the loss of endogenous analgesia and leads to enhanced pain sensation in CNP.

The effects of different hyperbaric oxygen manipulations in rats after traumatic brain injury.

The protective effects of hyperbaric oxygenation following traumatic brain injury have been widely investigated; however, few studies have made systematic comparisons between the different hyperbaric oxygenation manipulations and their corresponding effects. In this study, male Sprague-Dawley rats were observed at 4h, 15d and 75d after traumatic brain injury. The effects of the different hyperbaric oxygenation manipulations on the rats were compared based on morphological, molecular biological and behavioral tests. Our results showed that hyperbaric oxygenation inhibited cell apoptosis in the rat hippocampus and improved their physiological functions. The effects observed in the hyperbaric oxygen-early group were better than the hyperbaric oxygen-delayed group, and the hyperbaric oxygen-early-delayed group demonstrated the best effects among all the groups. Our results showed the hyperbaric oxygenation was recommended early and delayed post-traumatic brain injury and exposure to hyperbaric oxygenation should be prolonged. These findings provide new ideal therapeutic insight for the clinical treatment of traumatic brain injury.

Proteasome inhibitor ameliorates severe acute pancreatitis and associated lung injury of rats.

AIM: To observe the effect of proteasome inhibitor MG-132 on severe acute pancreatitis (SAP) and associated lung injury of rats. METHODS: Male adult SD rats were randomly divided into SAP group, sham-operation group, and MG-132 treatment group. A model of SAP was established by injection of 5% sodium taurocholate into the biliary-pancreatic duct of rats. The MG-132 group was pretreated with 10 mg/kg MG-132 intraperitoneally (ip) 30 min before the induction of pancreatitis. The changes in serum amylase, myeloperoxidase (MPO) activity of pancreatic and pulmonary tissue were measured. The TNF-alpha level in pancreatic cytosolic fractions was assayed with an enzyme-linked immunosorbent assay (ELISA) kit. Meanwhile, the pathological changes in both pancreatic and pulmonary tissues were also observed. RESULTS: MG-132 significantly decreased serum amylase, pancreatic weight/body ratio, pancreatic TNF-alpha level, pancreatic and pulmonary MPO activity (P < 0.05). Histopathological examinations revealed that pancreatic and pulmonary samples from rats pretreated with MG-132 demonstrated milder edema, cellular damage, and inflammatory activity (P < 0.05). CONCLUSION: The proteasome inhibitor MG-132 shows a protective effect on severe acute pancreatitis and associated lung injury of rats.

[Protective effect of proteasome inhibitor MG-132 in rats with severe acute pancreatitis and lung injury].

OBJECTIVE: To observe the protective effect of the proteasome inhibitor MG-132 in rats with severe acute pancreatitis (SAP) and the associated lung injury. METHODS: In rat models of the SAP established with injection of 5% sodium taurocholate into the biliary-pancreatic duct, the changes of the serum amylase and myeloperoxidase (MPO) activity in the pancreatic and lung tissues were evaluated. The pathological changes of the pancreatic and lung tissues were also observed. RESULTS: MG-132 significantly decreased serum amylase, pancreatic weight/body weight ratio, and pancreatic and pulmonary myeloperoxidase activity (P<0.05). Histopathological examinations revealed milder edema, cellular damage, and inflammation in the pancreatic and lung tissues of rats pretreated with the peptide (P<0.05). CONCLUSION: MG-132 ameliorates SAP and the associated lung injury in rats.