The Effects of Synthetic Oligopeptide Derived from Enamel Matrix Derivative on Cell Proliferation and Osteoblastic Differentiation of Human Mesenchymal Stem Cells

Enamel matrix derivative (EMD) is widely used in periodontal tissue regeneration therapy. However, because the bioactivity of EMD varies from batch to batch, and the use of a synthetic peptide could avoid use from an animal source, a completely synthetic peptide (SP) containing the active component of EMD would be useful. In this study an oligopeptide synthesized derived from EMD was evaluated for whether it contributes to periodontal tissue regeneration. We investigated the effects of the SP on cell proliferation and osteoblast differentiation of human mesenchymal stem cells (MSCs), which are involved in tissue regeneration. MSCs were treated with SP (0 to 1000 ng/mL), to determine the optimal concentration. We examined the effects of SP on cell proliferation and osteoblastic differentiation indicators such as alkaline phosphatase activity, the production of procollagen type 1 C-peptide and osteocalcin, and on mineralization. Additionally, we investigated the role of extracellular signal-related kinases (ERK) in cell proliferation and osteoblastic differentiation induced by SP. Our results suggest that SP promotes these processes in human MSCs, and that ERK inhibitors suppress these effects. In conclusion, SP promotes cell proliferation and osteoblastic differentiation of human MSCs, probably through the ERK pathway.     

Crack propagation life prediction of a perforated plate under thermal fatigue

Superheater outlet headers of boilers are well known to be subjected to the cycling of high pressure and high thermal stress during plant operations. Thermal stresses during cyclic operation are generally severest on the inside surface of the ligaments between the stub-tube holes, where many examples of ligament cracking due to thermal fatigue have been found recently. A method to predict the crack propagation life of the ligaments of boiler headers under thermal fatigue has been required. Firstly in this paper, to model the crack propagation behavior of the ligament regions of boiler headers, a perforated plate of normalized and tempered 2 1/4Cr–1Mo steel was examined under out-of-phase thermal fatigue at a maximum temperature of 600°C in the air. Inelastic analysis of the perforated plate under thermal fatigue was carried out, and the nonlinear fracture mechanics parameters such as the J and C^* integral were obtained by the line integral for observed cracks. A simplified method was proposed for predicting these parameters under displacement-controlled conditions such as thermal fatigue. In this method, the change of the macroscopic stress–strain relation of the perforated plate with propagating cracks was combined with the reference stress concept under displacement-controlled conditions. The predicted fracture mechanics parameters from this method coincided well with those from the inelastic analysis. The prediction of the crack propagation life on the basis of the proposed method provided a good correspondence with the test results of the perforated plate under thermal fatigue.     

Risk indicators for harboring periodontal pathogens

Mutations in the Agr locus of Arabidopsis thaliana impair the root gravitropic response. Root growth of agr mutants is moderately resistant to ethylene and to an auxin transport inhibitor. Vertically placed agr roots grow into agar medium containing IAA or naphthalene-1-acetic acid, but not into medium containing 2,4-D. Positional cloning showed that AGR encodes a root-specific member of a novel membrane-protein family with limited homology to bacterial transporters.     

Ion-induced photon spectroscopy of insulators and application to in-situ diagnostics of nanoparticle formation processes

Ion-induced photon emission under heavy-ion bombardment has been studied over an energy range from near-infrared to vacuum-ultraviolet. Time-resolved optical devices with fast-response CCD cameras detected photons from a-SiO₂ under implantation with negative Cu ions of 60 keV, up to a dose rate of 100 μA/cm². The ion-induced photon spectra consisted of sharp line spectra due to isolated atoms of Si, Cu and a broad band of visible light. The line spectra resulted from an ion-induced glow above the surface and indicated pronounced outward transport of Cu atoms to the vacuum. Intensity of the line spectra and the broad band varied non-linearly with dose and dose rate. The in-situ spectroscopy provided diagnostic information of surface- and intra-solid processes associated with nanoparticle formation at high dose rates. The Cu sublimation reflected from presence of a Cu-depleted zone beneath the surface, which is one of the important factors to form a two-dimensional arrangement of nanoparticles.     

Synthetic voices for computers

The two methods described for giving voices to computers recognize the importance of economical storage of speech information and extensive vocabularies, and consequently are based on principles of speech synthesis. The first, formant synthesis, generates connected speech from low-bit-rate representations of spoken words. The second, text synthesis, produces connected speech solely from printed English text. For both methods the machine must contain stored knowledge of fundamental rules of language and acoustic constraints of human speech. Formant synthesis from an input information rate of about 1000 bits per second is demonstrated, as is text synthesis from a rate of about 75 bits per second. To give the reader an opportunity to evaluate some of the results described, a sample recording is available; see Appendix A for details.     

A spectrofluorometric method for determining plasma allantoin based on the glyoxylate reductase reaction

Messenger RNA has been isolated from rat lens tissue. The mRNA species which codes for the A2 chain of alpha-crystallin, revealed the same extremely high sedimentation value (14S) as the corresponding messenger from calf lens. However, it has been shown that in rat lens the 14-S messenger preparation directs the synthesis of an additional alpha-crystallin chain, designated as alpha-X with an approximate molecular weight of 24000. For comparative purpose crystallin synthesis has also been studied as well in cultured rat lens cells as in the rat lens cell-free system.