Preparation of poly(vinyl alcohol)/silver-zeolite composite hydrogels by UV-irradiation

Poly(vinyl alcohol) (PVA)/Ag-zeolite nanocomposite hydrogels were prepared by UV irradiation using PVA solution mixed with Ag-zeolite nanoparticles. Physical properties and changes in morphology of the PVA/Ag-zeolite hydrogels were investigated. The PVA/Ag-zeolite hydrogels were prepared at a PVA concentration of 9 wt% with a UV irradiation distance of 15 cm, where gel fraction and swelling ratio were optimized. Hardness of the PVA/Ag-zeolite hydrogels decreased with increasing amounts of Ag-zeolite, reaching that of soft elastomer when the amount of Ag-zeolite was 5 % by weight. The PVA/Ag-zeolite hydrogels showed strong antimicrobial activities against Staphylococcus aureus and Klebsiella pneumoniae, inducing a reduction of bacteria of over 99.9 % at a Ag-zeolite content of 3 wt%.     

Flexibilide Obtained from Cultured Soft Coral Has Anti-Neuroinflammatory and Analgesic Effects through the Upregulation of Spinal Transforming Growth Factor-β1 in Neuropathic Rats

Chronic neuroinflammation plays an important role in the development and maintenance of neuropathic pain. The compound flexibilide, which can be obtained from cultured soft coral, possesses anti-inflammatory and analgesic effects in the rat carrageenan peripheral inflammation model. In the present study, we investigated the antinociceptive properties of flexibilide in the rat chronic constriction injury (CCI) model of neuropathic pain. First, we found that a single intrathecal (i.t.) administration of flexibilide significantly attenuated CCI-induced thermal hyperalgesia at 14 days after surgery. Second, i.t. administration of 10-μg flexibilide twice daily was able to prevent the development of thermal hyperalgesia and weight-bearing deficits in CCI rats. Third, i.t. flexibilide significantly inhibited CCI-induced activation of microglia and astrocytes, as well as the upregulated proinflammatory enzyme, inducible nitric oxide synthase, in the ipsilateral spinal dorsal horn. Furthermore, flexibilide attenuated the CCI-induced downregulation of spinal transforming growth factor-β1 (TGF-β1) at 14 days after surgery. Finally, i.t. SB431542, a selective inhibitor of TGF-β type I receptor, blocked the analgesic effects of flexibilide in CCI rats. Our results suggest that flexibilide may serve as a therapeutic agent for neuropathic pain. In addition, spinal TGF-β1 may be involved in the anti-neuroinflammatory and analgesic effects of flexibilide.     

Study on viscosity changes with talc in microcellular foaming process

In the processing of microcellular foamed polymer products, one of the most important factors is the dependence of rheology on the mixture ratio of the polymer and the gas used as the blowing agent. The formation of a cell by employing the thermodynamic instability of the gas in a one-phase condition is the principle behind microcellular foaming. The viscosity change of the polymer and gas mixture is important in designing dies and molds and affects the quality of the microcellular foaming product. In this experiment, the extruder was modified to mix polymer with gas under a one-phase melted condition. The mixed polymer with gas was run through various capillary die shapes to measure the change in polymer viscosity against the gas supply rate. This paper describes the effect of talc and the blowing agent on the viscosity in continuous microcellular processes, revealing major factors in determining the viscosity of a polymer and gas mixture.     

Compatibilization of immiscible poly(<Emphasis Type="Italic">l</Emphasis>-lactide) and low density polyethylene blends

Blends of poly(l-lactide) (PLA) and low density polyethylene (LDPE) were prepared by melt mixing in order to improve the brittleness of PLA. A reactive compatibilizer with glycidyl methacrylate (GMA), PE-GMA, was required as a compatibilizer due to the immiscibility between PLA and LDPE. It contributes to reduce the domain size of dispersed phase and enhance the tensile properties of PLA/LDPE blends, especially for PLA matrix blends. A reaction product between PLA and PE-GMA, which was formed during melt-mixing and considered to act as a reactive compatibilizer, was characterized using¹H-NMR spectroscopy.     

Preparation of poly(vinyl acetate)/clay and poly(vinyl acetate)/poly(vinyl alcohol)/clay microspheres

Poly(vinyl acetate) (PVAc)/poly(vinyl alcohol)(PVA)/montmorillonite (MMT) clay nanocomposite microspheres with a core/shell structure have been developed via a suspension polymerization approach. In order to prepare the PVAc/MMT and PVAc/PVA/MMT nanocomposite microspheres, which are promising precursor of PVA/MMT nanocomposite microspheres, suspension polymerization of vinyl acetate with organophilic MMT and heterogeneous saponification were conducted. A quaternary ammonium salt, cetyltrimethylammonium bromide, was mixed with the MMT in the monomer phase prior to the suspension polymerization. The rate of conversion decreased with an increase in MMT concentration. The incorporation of MMT into the PVAc was verified by FT-IR spectroscopy. Organic vinyl acetate monomers were intercalated into the interlayer regions of organophilic clay hosts and followed by suspension polymerization. Partially saponified PVA/MMT nanocomposite microspheres with a core/shell structure were successfully prepared by heterogeneous saponification.     

Prediction and interpretation of hydraulic permeability for nonwoven fabrics considering hypothetical 2-D layer

The permeability defined by Darcy’s law indicates the degree of ability that a fluid can flow through nonwoven media under a differential pressure in laminar flow. The permeability generally indicates the specific permeability or absolute permeability. On the other hand, if the fluid is water, the permeability indicates the hydraulic conductivity or permeability coefficient. The permeability is one of the important properties for nonwoven media and a prediction of the permeability acts as a bridge between the manufacturing technology and performance requirements. Because capillary channel theory aims to make the flow of fluid easier and more understandable, many models are based on capillary channel theory. On the other hand, the theory has a limitation in that it is unsuitable for high porosity media. In this study, a very thin downstream layer, which was suggested by Lifshutz [9], was introduced to derive a prediction model of hydraulic permeability. Needle-punched and spunbonded nonwoven fabrics with various basis weights were used in the cross-plain water permeability test. From this ‘thin layer’ model, reasonable agreement between the predicted and experimental results was obtained.     

Mitigating surface urban heat island by a tree protection policy: A case study of The Woodland,Texas, USA

The Woodlands Township, TX, has a tree protection policy that consists of tree removal permits and minimum tree and shrub cover regulations. This paper examined the effect of The Woodlands’ tree protection policy on surface urban heat island (SUHI) at the neighborhood scale by comparing the mean land surface temperatures (LSTs) derived from 37 thermal infrared bands of Landsat TM images between The Woodlands’ neighborhoods and nearby control neighborhoods without such a policy. To rule out the effect of confounding factors that may influence LSTs, the control neighborhoods were selected to be similar in physical and socioeconomic status to The Woodlands’ neighborhoods. LSTs of The Woodlands’ neighborhoods were, on average, 1.5–3.9 °C lower than those of the control neighborhoods. The cooling effect of The Woodlands’ tree protection policy was more prominent in summer when SUHI mitigation was mostly needed. Based on these findings, it can be concluded that a local tree protection policy is effective in mitigating SUHI at the neighborhood scale.     

Licochalcone A prevents adipocyte differentiation and lipogenesis via suppression of peroxisome proliferator-activated receptor γ and sterol regulatory element-binding protein pathways

Licochalcone A (LA) has been shown to exert multiple pharmacological effects, including anti-inflammatory, antiparasitic, antifungal, anticancer, and osteogenic activities. The present study investigated the ability of LA to suppress the differentiation of 3T3-L1 preadipocytes, and its antiobesity activity was explored using high fat diet (HFD)-fed ICR mice. During the terminal differentiation process, 3T3-L1 preadipocytes were treated with LA, and the lipid contents were quantified along with any changes in the expression of biomarkers associated with adipocyte differentiation and lipogenesis. The results show that LA significantly reduced lipid accumulation and down-regulated the expression of peroxisome proliferator-activated receptor γ, CCAAT/enhancer binding protein α, sterol regulatory element-binding protein 1c, and their target genes (fatty acid binding protein, fatty acid synthase, stearoyl-CoA desaturase 1, and glycerol-3-phosphate acyltransferase). In an animal study, body weight, triglyceride, cholesterol, and nonesterified fatty acid levels in the group given 10 mg/kg LA were significantly decreased by 14.0, 48.2, 58.9, and 73.5%, respectively. Transverse microcomputed tomography indicated that visceral fat depots in LA-treated mice were markedly reduced when compared with those of the HFD control group. In summary, these results suggest that LA exerts an antiobesity effect and that it is a candidate for future clinical trials.     

Hericium erinaceus mushroom extracts protect infected mice against Salmonella Typhimurium-Induced liver damage and mortality by stimulation of innate immune cells

The present study investigated the antibacterial effect of four extracts from the fruitbody of the edible medicinal mushroom Hericium erinaceus (hot water extract, HWE; microwave/50% ethanol extract, MWE; acid extract, ACE; and alkaline extract, AKE) against murine salmonellosis. The extracts had no effect on Salmonella ser. Typhimurium growth in culture. Nor were the extracts toxic to murine macrophage cells, RAW 264.7. HWE and MWE stimulated uptake of the bacteria into the macrophage cells as indicated by increased colony-forming unit (CFU) counts of the contents of the lysed macrophages infected with Salmonella Typhimurium for 30 and 60 min. Two hours postinfection, the bacterial counts increased in the macrophages, but 4 and 8 h postinfection the HWE- and MWE-treated cells showed greater activity against the bacteria than the control. HWE- and MWE-treated noninfected macrophages had altered morphology and elevated inducible nitric oxide (NO) synthase (iNOS) mRNA expression. In the presence of S. Typhimurium, iNOS mRNA expression was further increased, accompanied by an increase in NO production. Histology assays of the livers of mice infected with a sublethal dose (1 × 10(4) CFU) of S. Typhimurium showed that HWE and MWE, administered by daily intraperitoneal injection, protected against necrosis of the liver, a biomarker of in vivo salmonellosis. The lifespans of mice similarly infected with a lethal dose of S. Typhimurium (1 × 10(5) CFU) were significantly extended by HWE and MWE. β-Glucan, known to stimulate the immune system, was previously found to be present in high amounts in the active extracts. These results suggest that the mushroom extract activities against bacterial infection in mice occur through the activation of innate immune cells.     

Inducible nitric oxide synthase and cyclooxygenase-2 participate in anti-inflammatory activity of imperatorin from Glehnia littoralis

In this study, we have investigated the anti-inflammatory effects of imperatorin, a compound isolated from the roots of Glehnia littoralis, using a lipopolysaccharide (LPS)-stimulated mouse macrophage (RAW264.7) in vitro and a carrageenan (Carr)-induced mouse paw edema model in vivo. When RAW264.7 macrophages were treated with imperatorin together with LPS, a significant concentration-dependent inhibition of NO production was detected. Western blotting revealed that imperatorin blocked the protein expression of iNOS and cyclooxygenase-2 (COX-2) in LPS-stimulated RAW264.7 macrophages significantly. In the anti-inflammatory test, imperatorin decreased the paw edema at 4 and 5 h after Carr administration and increased the activities of catalase, superoxide dismutase, and glutathione peroxidase in paw edema. We also demonstrated that imperatorin significantly attenuated the malondialdehyde level in the edema paw at the fifth hour after Carr injection. Imperatorin decreased the NO and tumor necrosis factor and prostaglandin E2 levels on serum at 5 h after Carr injection. Western blotting revealed that imperatorin decreased Carr-induced iNOS and COX-2 expressions at 5 h in edema paw. An intraperitoneal injection treatment with imperatorin also diminished neutrophil infiltration into sites of inflammation as did indomethacin. The results suggested that imperatorin had anti-inflammatory effects in LPS-stimulated RAW 264.7 cells and Carr-injected mice, respectively. In addition, inhibition of elevated iNOS and COX-2 protein expression as well as neutrophil infiltration of Carr-injected paws may be involved in the beneficial effects of imperatorin.