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Abstract: Previously, we reported that a novel secretory protein, pancreatic adenocarcinoma up-regulated factor (PAUF), which is highly expressed in pancreatic cancer and mediates the growth and metastasis of pancreatic cancer cells. In this study, we generated and characterized a 2′-fluoropyrimidine modified RNA aptamer (P12FR2) directed against human PAUF. P12FR2 binds specifically to human PAUF with an estimated apparent KD of 77nM. P12FR2 aptamer inhibits PAUF-induced migration of PANC-1, human pancreatic cancer cells, in a wound healing assay. Moreover, intraperitoneal injection of P12FR2 decreased tumor growth by about 60% in an in vivo xenograft model with CFPAC-1 pancreatic cancer cells, without causing a loss of weight in the treated mice. Taken together, we propose here that PAUF-specific RNA aptamer, P12FR2, has the potential to be effective in the therapy of human pancreatic cancer. [Copyright &y& Elsevier]

Recently, attempts have been made to use silicon carbide (SiC) ceramics as a fuel compact in nuclear reactors. However, the use of sintering additives in the conventional sintering of SiC leads to a coarse microstructure with high porosity and large grains due to the low sinterability and the large amount of grain boundaries or a second phase, deteriorating the mechanical properties, and hence limiting widespread industrial applications. In this study, polycarbosilane (PCS) and spark plasma sintering (SPS) as the SiC precursor and sintering method, respectively, were applied to overcome the low sinterability and the use of sintering additives. As the raw material, amorphous PCS was prepared by pyrolysis at 1000 °C. To decrease the particle size, pyrolyzed PCS powder was subjected to ball milling by using high-energy ball milling. The ball-milled amorphous PCS powder was sintered by SPS. Sintering was carried out at different temperatures (i.e., 1700, 1800, and 1900 °C) and pressures (i.e., 40 and 80 MPa). After SPS, the core/rim structure of the sintered pellet was formed on account of the oxygen originating from the native oxide layer and free carbon in the PCS powder as the raw materials. In the core/rim structure comprising the core, as well as the intermediate and rim regions, the microstructure and chemistry of each region exhibited marginal difference with respect to the free carbon and oxygen. The phase fraction of α-SiC increased from the rim region to core region due to the discrepancy of actual loaded pressure on account of friction with the wall surface. The existing carbon was verified to be graphitized carbon. Owing to the short reaction time, graphitization did not completely proceed, and deficient graphitization led to graphitized carbon as not graphite. The introduced oxygen changed to amorphous SiO 2 , which was applied to the sintering-additive-like liquid-phase sintering. [ABSTRACT FROM AUTHOR]

SiC was sintered by spark plasma sintering (SPS) using polycarbosilane (PCS), and the effects of pressure on the sintering behavior of SiC during SPS were investigated. The pressure conditions were set as 40 and 80 MPa, and pyrolyzed PCS was used to induce reactive sintering during heat treatment such as pyrolysis, crystallization, and crystal growth. According to the results, a high pressure accelerated the reactions in samples and resulted in a high-density body consisting of small-sized grains; however, it induced a phase transition to the α phase, which is stable at high temperatures. [ABSTRACT FROM AUTHOR]

The present study focuses on the growth of carbon nanotubes (CNTs) on Fe-containing zeolites coated porous ceramics by implementing three different and independent techniques, successively. Direct foaming-derived porous ceramics were subjected to hydrothermal reaction for on-site growth of NaA zeolites within it. The porous ceramics-zeolite composite was subjected to ion-exchange reaction to obtain the catalyst for CNT synthesis. Multi-walled CNTs (MWCNTs) were grown by catalytic chemical vapour deposition (CCVD) process using acetylene as carbon source. Microstructural, thermogravimetric and spectroscopic analyses showed distinctive differences in terms of hollow structural feature, yield and crystallinity of the MWCNTs with different reaction temperatures. [ABSTRACT FROM AUTHOR]

Three mol. % yttria stabilized zirconia (3Y-TZP) with Graphene platelets (GNPs) powder mixture was produced by ball milling using dimethyl formamide (DMF) as dispersion media. The GNPs-reinforced 3Y-TZP composites were densified (~99%) by field assisted sintering technology (FAST). A homogeneous dispersion of GNPs in 3Y-TZP is observed from the sintered samples, and the GNPs are bent and embedded between the grains, which results in increasing the contact area. The trans-granular mechanism of crack propagation becomes increasingly dominant by adding GNPs. The fracture toughness reaches 15.3 MPa·m 1/2 , as tested by single-edge notched beam method, which reflects an increase of 61% compared to GNPs-free 3Y-TZP. On the other hand, with higher GNPs content, the improvement in fracture toughness is limited. Toughening mechanisms, as determined through micro-hardness testing, including pull out, crack deflection, crack bridging, and micro-cracks, are observed and discussed. [ABSTRACT FROM AUTHOR]

A wet-chemical synthesis and microwave calcination approach was found to be efficient for synthesizing α-alumina powders and polycrystals with high levels of lattice defects. The defects of the as-produced powders were determined from the optical transmittance of spark-plasma-sintered compacts with an identical microstructure using a conventional calcination method. The existence of a high lattice defect concentration was verified by positron annihilation lifetime analysis and X-ray diffraction. The microwave-activated lattice defect phenomenon has potential applications in the production of semiconductor materials or films with high chemical activity or crystal doping. [ABSTRACT FROM AUTHOR]

Commercial ZrO2/carbon nanotube (CNT) composite powders were sintered by spark plasma sintering (SPS). The densification behavior during SPS was investigated by analysis of recorded shrinkage plots, and addition of CNTs was found to alter the sintering mechanism. Moreover, the addition of CNTs could also lead to refined grain size, improved fracture toughness as well as reduced Vickers hardness. Raman spectroscopy revealed an initially decreasing and then increasing tendency for the tetragonal to monoclinic phase transformation during indentation of the composites. [ABSTRACT FROM AUTHOR]

Highly transparent hydroxyapatite (HA) ceramics with nanosized grains were fabricated by spark plasma sintering at ∼900–1000°C and 80MPa. HA decomposition was not observed after sintering at 1000°C for 10min. The total forward transmission was more than 70% at 400nm, and approached the theoretical value of 89% in the infrared wavelength range. The high transmission, indicating low light absorption and scattering, was attributed to the fine and dense microstructures. [ABSTRACT FROM AUTHOR]

Transparent, nanocrystalline hydroxyapatite with an average grain size of 170nm was fabricated by spark plasma sintering. The superplastic flow behavior of the hydroxyapatite specimen was examined at temperatures ranging from 950 to 1050°C. The hydroxyapatite specimens exhibited superplasticity under the test conditions examined. A maximum elongation of 486% was achieved at 1000°C and an initial strain rate of 1.0×10–4 s−1. The excellent tensile ductility in transparent, nanocrystalline hydroxyapatite was attributed to the very fine grain size and pore-free microstructure. [ABSTRACT FROM AUTHOR]

Abstract: A new method to prepare PLA/CMP (poly-l-lactide/calcium metaphosphate) composite scaffolds was developed for effective bone tissue engineering. This novel sintering method is composed of pressing the mixture of PLA, CMP, and salt particles at 150MPa for 3min followed by heat treatment at 210°C for 30min. The scaffolds had a homogeneously interconnected porous structure without a skin layer, and they exhibited a narrower pore size distribution and higher mechanical strength in comparison with scaffolds made by a solvent casting method. The scaffolds were seeded by osteoblasts and cultured in vitro or implanted into nude mice subcutaneously for up to 5 weeks. The number of cells attached to and proliferated on the scaffolds at both in vitro and in vivo was in the order of; PLA by novel sintering<PLA/CMP by solvent casting<PLA/CMP by novel sintering. In addition, the alkaline phosphatase activity of and calcium deposition in the scaffolds explanted from mice were enhanced significantly for the scaffolds by novel sintering compared to them by solvent casting. The in vitro results agreed well with the in vivo data. Such a superior characteristic of the novel sintering method should have resulted from the fact that the CMP particles could contact directly with cells/tissues to stimulate the cell proliferation and osteogenic differentiation, while the CMP particles would be coated by polymers and hindered to interact with cells/tissues in the case of a solvent casting method. As the novel sintering method does not use any solvents it offers another advantage to avoid problems associated with solvent residue. [Copyright &y& Elsevier]

In the present study, the in vitro biocompatibility of calcium metaphosphate (CMP) with human bone marrow stromal cells (HBMSCs) and its effect on osteoblastic differentiation have been investigated. Powder and disk forms of CMP do not exert a cytotoxic effect on the HBMSCs undergoing osteoblastic differentiation. In addition, the HBMSCs adhere to the surface of the CMP disk as successfully as to the culture plate or hydroxyapatite (HA) disk. The HBMSCs adhered to either the HA or CMP disk display an undistinguishable actin arrangement and cellular phenotypes, indicating that the CMP does not disrupt normal cellular responses. An analysis of the differentiation of the HBMSCs cultured on culture plate, the HA and the CMP disk shows that three matrices are capable of supporting osteoblastic differentiation of the HBMSCs as accessed by alkaline phosphatase (ALP) staining. Further molecular analysis of osteoblastic differentiation of HBMSCs reveals that the CMP disk has a better ability than the HA disk to induce an expression of osteoblast-related genes, including ALP, osteoprotegerin (OPG), a decoy receptor for RANK ligand, and osteopontin (OPN), a non-collagenous bone matrix protein. The results demonstrate that, in addition to favorable biocompatibility, the CMP can stimulate osteoblastic differentiation of the HBMSCs in vitro. [Copyright &y& Elsevier]

Modern technology, including 3D printing, provides enormous potential for shape- and size-tailored treatments, especially in orthopedic surgery and dentistry. However, for a medical device produced in the clinical setting that is not compatible with autoclaving or gas sterilization, the choices are very limited, especially because there are a lot of obstacles to using a radiation facility to sterilize a few small-size devices. The goal of this study was to verify the efficacy of laser sterilization of discs made from hydroxyapatite (HA), a material that can be 3D printed and widely used as bone substitute. For this purpose, we compared sterilization efficacy for E. coli and S. mutans when using a range of laser, γ-ray, and e-beam irradiation. Furthermore, we compared biocompatibility by culturing adult stem cells and MC3T3-E1 on HA discs before and after irradiation. Irradiation by UV-C (266 nm) at 100 mJ/cm2 showed 3 kGy of γ-ray or e-beam equivalent sterilization efficacy, without causing physical or chemical changes in the HA discs. In conclusion, in addition to offering affordable maintenance costs, laser sterilization can be used in small-size facilities and can sterilize an object within nanoseconds; this demonstrates its potential to be used on custom small-size medical devices as an alternative sterilization technique that can replace autoclaving, gas sterilization, or the use of radiation facilities. [ABSTRACT FROM AUTHOR]