Effect of glycerol cross-linking and PDI on the shape memory effect and mechanical properties of polyurethane

A series of shape memory polyurethane (PU) copolymers synthesized from 1,4-phenyldiisocyanate (PDI), poly(tetramethyleneglycol) (PTMG), 1,4-butanediol (BD) as a chain extender, and glycerol as a cross-linking agent were tested for the mechanical properties and the shape memory effect at the temperature 20 °C above melting temperature (T _m), and were compared with other PUs synthesized from 4,4′-methylene-bis-phenyldiisocyanate (MDI), PTMG, and BD. Mechanical properties and shape memory effect were improved substantially by adopting both PDI and glycerol. Interestingly, enthalpy of melting and T _m were not affected by the glycerol content. Vibration and shock absorption ability was investigated by measuring both loss tan δ and storage modulus with dynamic mechanical analyzer (DMA).     

Mechanical properties of semi-interpenetrating polymer network hydrogels based on poly(2-hydroxyethyl methacrylate) copolymer and chitosan

Semi-interpenetrating polymeric network (semi-IPN) hydrogels based on poly(2-hydroxyethyl methacrylate) (PHEMA) and poly(2-hydroxyethyl methacrylate-co-sodium methacrylate) [P(HEMA-co-SMA)], and chitosan with different molecular weights were prepared by crosslinking with ethylene glycol dimethacrylate (EGDMA) and poly(ethylene glycol) diacrylate (PEGDA) and their gelation time, water content, mechanical properties, and morphology were investigated. In consideration of the influence of the molecular weight of chitosan, there is no big difference in the water content, while tensile properties and compressive modulus increased as the molecular weight of chitosan increased. The water content increased and tensile properties and compressive modulus decreased with increasing SMA concentration. Considering the effect of the crosslinking agent, PEGDA had higher water content and lower tensile and compressive moduli than EGDMA. It is suggested that PHEMA/chitosan and P(HEMA-co-SMA)/chitosan semi-IPN hydrogels with different structures and physical properties can be prepared depending on the molecular weight of chitosan, the copolymerization with SMA, and the crosslinking agent type.     

Miscibility of flame retardant epoxy resin with poly(ethylene terephthalate) and the characterizations of the blends

Epoxy resin containing bromine compound was melt blended with PET to obtain flame retardant polymer. The blend product was characterized by DSC, SEM, intrinsic viscosity and melt index measurements. The reaction between the epoxy group of DGEBBA (diglycidyl ether of brominated bisphenol A) and the carboxyl (or hydroxyl) end group of PET led to cross-linking of PET chains, and the intrinsic viscosity and melt index (MI) were increased in the range of equivalent amount of epoxy resin (within 1 %). DSC data revealed that the epoxy resin was not located in the crystalline region but was appeared in the amorphous region of PET matrix. Good miscibility of epoxy resin resulted in the decrease of crystallization temperature and glass transition temperature of PET. The blend was spun into fiber without any problems such as swelling or draw resonance, however, the mechanical properties were decreased as the amount of the DGEBBA was increased.     

Functional efficacy analysis of Angelica gigas Nakai on chicken myoblast cells through cell‐based in vitro assay

The value‐added products in livestock industry is one of the key issues in order to maximize the revenue and to create a new business model. Numerous studies have suggested application of herbal plants as feed additives to increase health, productivity, and/or high‐quality product in livestock. In this study, the first experiment was designed to develop in vitro evaluation system by using primary chicken myoblast (pCM) cells isolated from pectoralis major of 10‐day‐old male embryos. Subsequently, to evaluate effects of Korean Danggui Angelica gigas Nakai (AGN), we optimized the concentration of AGN root extract for treatment of primary pCM cells. After the treatment of AGN root extract, we compared proliferation and differentiation capacity, and also examined the gene expression. In the second experiment, the next generation sequencing analysis was performed to compare the different patterns of the global gene expression in pCM cells treated with AGN extract. Three up‐regulated (pancreas beta cells, fatty acid metabolism and glycolysis) and one down‐regulated (adipogenesis) gene sets were characterized suggesting that the AGN extract affected the metabolic pathways for the utilization of fat and glucose in chicken muscle cells. Furthermore, we validated the expression patterns of the up‐regulated genes (GCLC, PTPN6, ISL1, SLC25A13, TGFBI, and YWHAH) in the AGN‐treated pCM cells by quantitative RT‐PCR. These results demonstrated that the treatment of AGN extract decreased proliferation and differentiation of pCM cells, and affected the metabolic pathways of glucose and fatty acids. Moreover, AGN extract derived from byproducts such as stem and leaf also showed the reduced proliferation patterns on AGN‐treated pCM cells. Taken together, pCM cell‐based in vitro assay system could be primarily and efficiently applied for evaluating the biofunctional efficacy of various feed additive candidates.     

Comparative study of the developmental competence of cloned pig embryos derived from spermatogonial stem cells and fetal fibroblasts

Spermatogonial stem cells (SSC) are promising resources for genetic preservation and restoration of male germ cells in humans and animals. However, no studies have used SSC as donor nuclei in pig somatic cell nuclear transfer (SCNT). This study investigated the potential for use of porcine SSC as a nuclei donor for SCNT and developmental competence of SSC‐derived cloned embryos. In addition, demecolcine was investigated to determine whether it could prevent rupture of SSC during SCNT. When the potential of SSC to support embryonic development after SCNT was compared with that of foetal fibroblasts (FF), SSC‐derived SCNT embryos showed a higher (p < .05) developmental competence to the blastocyst stage (47.8%) than FF‐derived embryos (25.6%). However, when SSC were used as donor nuclei in the SCNT process, cell fusion rates were lower (p < .05) than when FF were used (61.9% vs. 75.8%). Treatment of SSC with demecolcine significantly (p < .05) decreased rupture of SSC during the SCNT procedure (7.5% vs. 18.8%) and increased fusion of cell‐oocyte couplets compared with no treatment (74.6% vs. 61.6%). In addition, SSC‐derived SCNT embryos showed higher blastocyst formation (48.4%) than FF‐derived embryos without (28.4%) and with demecolcine treatment (17.4%), even after demecolcine treatment. Our results demonstrate that porcine SSC are a desirable donor cell type for production of SCNT pig embryos and that demecolcine increases production efficiency of cloned embryos by inhibiting rupture of nuclei donor SSC during SCNT.     

Efficacy of Liriope platyphylla on Hematology and Immune Response in Olive Flounder,Paralichthys olivaceus,Against Flexibacter maritimus Infection

The effect of different solvent‐based (methanol, ethanol, and aqueous) extracts of Liriope platyphylla at 0, 0.1, 1.0, and 2.0 mg doses on hematology and innate immune response in olive flounder, Paralichthys olivaceus, against Flexibacter maritimus is reported. The red blood cells and white blood cells significantly increased with ethanol and aqueous extracts with any dose against F. maritimus while the hematocrit level significantly increased with methanol or ethanol extracts. However, the hemoglobin content significantly increased irrespective of the doses and type of extracts, whereas the mean corpuscular volume, mean corpuscular hemoglobin, and mean corpuscular hemoglobin concentration significantly decreased. The lymphocytes and monocytes significantly increased in all doses and extracts, whereas neutrophils increased in ethanol or aqueous extracts. However, the thrombocytes level neither the doses nor extracts did not significant changes to the control against pathogen. Total protein and globulin levels significantly increased with all the doses of ethanol extract while does not significant change in methanol extract. The phagocytic activity and complement activity were significantly enhanced with any dose of ethanol extract while with aqueous extract it was only at 1.0 and 2.0 mg doses. At all the doses of each extract significantly enhanced the leucocytes activity against F. maritimus. The results confirm that the ethanolic and aqueous extracts of L. platyphylla stimulate the immune response against F. maritimus in P. olivaceus.     

Long-term chemotherapy with lomustine of intracranial meningioma occurring in a miniature schnauzer

A 14-year-old male miniature schnauzer was referred to us because it was circling to the right. A mass in the diencephalon was noted on brain magnetic resonance images. The dura was thickened with marked linear enhancement after contrast administration. Based on diagnostic image analysis, this lesion strongly suggested meningioma. The patient's symptoms were well controlled by a combination therapy of prednisolone and lomustine (CCNU), and survived for thirteen months after diagnosis. This case was diagnosed as a meningioma based on histopathological findings. This report describes the clinical findings, imaging characteristics, and pathologic features of a diencephalic and mesencephalic meningioma and long-term survival after lomustine and prednisolone therapy.     

Curative effect of autologous platelet-rich plasma on a large cutaneous lesion in a dog

A dorsal tail mass (1 × 1.2 cm) was observed on a 10-year-old castrated male, Shih-tzu dog. A biopsy of the mass was performed and diagnosed histopathologically as a follicular cyst. A necrotic lesion (2.5 × 3 cm) developed at the biopsy site 1 week after sampling and failed to respond to 2 weeks of normal saline cleansing and systemic antibiotic administration. Autologous platelet-rich plasma was applied to the lesion which gradually improved over a 4-week period possibly by a contribution to the secretion of growth hormone, which can accelerate tissue regeneration. This case report suggests that autologous PRP may be beneficial in the management of large skin defects or in delayed wound healing.     

Low dietary inorganic phosphate affects the lung growth of developing mice

Inorganic phosphate (Pi) plays a critical role in diverse cellular functions, and regulating the Pi balance is accomplished by sodium-dependent Pi co-transporter (NPT). Pulmonary NPT has recently been identified in mammalian lungs. However, to date, many of the studies that have involved Pi have mainly focused on its effect on bone and kidney. Therefore, current study was performed to discover the potential effects of low Pi on the lung of developing transgenic mice expressing the renilla/firefly luciferase dual reporter gene. Two-weeks old male mice divided into 2 groups and these groups were fed either a low PI diet or a normal control diet (normal: 0.5% Pi, low: 0.1% Pi) for 4 weeks. After 4 weeks of the diet, all the mice were sacrificed. Their lungs were harvested and analyzed by performing luciferase assay, Western blotting, kinase assay and immunohistochemistry. Our results demonstrate that low Pi affects the lungs of developing mice by disturbing protein translation, the cell cycle and the expression of fibroblast growth factor-2. These results suggest that optimally regulating Pi consumption may be important to maintain health.