Effect of silicon-doped calcium phosphate cement on angiogenesis based on controlled macrophage polarization.

Vascularization is an important early indicator of osteogenesis involving biomaterials. Bone repair and new bone formation are associated with extensive neovascularization. Silicon-based biomaterials have attracted widespread attention due to their rapid vascularization. Although calcium phosphate cement (CPC) is a mature substitute for bone, the application of CPC is limited by its slow degradation and insufficient promotion of neovascularization. Calcium silicate (CS) has been shown to stimulate vascular endothelial proliferation. Thus, CS may be added to CPC (CPC-CS) to improve the biocompatibility and neovascularization of CPC. In the early phase of bone repair (the inflammatory phase), macrophages accumulate around the biomaterial and exert both anti- and pro-inflammatory effects. However, the effect of CPC-CS on macrophage polarization is not known, and it is not clear whether the effect on neovascularization is mediated through macrophage polarization. In the present study, we explored whether silicon-mediated macrophage polarization contributes to vascularization by evaluating the CPC-CS-mediated changes in the immuno-environment under different silicate ion contents both in vivo and in vitro. We found that the silicon released from CPC-CS can promote macrophage polarization into the M2 phenotype and rapid endothelial neovascularization during bone repair. Dramatic neovascularization and osteogenesis were observed in mouse calvarial bone defects implanted with CPC-CS containing 60% CS. These findings suggest that CPC-CS is a novel biomaterial that can modulate immune response, promote endothelial proliferation, and facilitate neovascularization and osteogenesis. Thus, CPC-CS shows potential as a bone substitute material.

Pneumolysin/Plasma Protein Adsorption, Bacterial Adherence, and Cell Adhesion Characteristics of a Cell-Membrane-Mimicking Polymer System.

This study delivers the first report on a cell-membrane-mimicking polymer system, poly[oxy(4-(13-cholenoatenonyl)-1,2,3-triazoyl-1-methyl)ethylene-random-oxy(4-(13-phosphorylcholinenonyl)-1,2,3-triazoyl-1-methyl)ethylene] (PGA-CholmPCn) films in various compositions in terms of physicochemical properties, protein adsorptions, bacterial adherences, and human cell adhesions. Higher Chol-containing PGA-CholmPCn in a self-assembled multi-bilayer membrane structure is confirmed to show excellently high affinity to pneumolysin (a cytolysin) and its C-terminal fragment (domain 4) but substantially suppressed affinity to the N-terminal fragment (domains 1-3) and further to plasma proteins. Furthermore, the adherences of pathogenic bacteria are increased favorably; however, the adhesion and proliferation of a human HEp-2 cell line are hindered severely. In contrast, higher-PC-containing PGA-CholmPCn membranes promote HEp-2 cell adhesion and proliferation but significantly suppress the adsorptions of pneumolysin and its fragments and plasma proteins as well as bacterial adherence. The results collectively confirm that PGA-CholmPCn can yield a membrane platform enriched with hydrophobic Chol and hydrophilic and zwitterionic PC moieties in any desired compositions, providing highly selective and sensitive physicochemical characters and biocompatibilities which are demanded for applications in various fields including biomedicine, cosmetics, and environmentally friendly consumer products.

Verification of endocrinological functions at a short distance between parametric speakers and the human body.

OBJECTIVE: In recent years, a new type of speaker called the parametric speaker has been used to generate highly directional sound, and these speakers are now commercially available. In our previous study, we verified that the burden of the parametric speaker was lower than that of the general speaker for endocrine functions. However, nothing has yet been demonstrated about the effects of the shorter distance than 2.6 m between parametric speakers and the human body. Therefore, we investigated the distance effect on endocrinological function and subjective evaluation. METHODS: Nine male subjects participated in this study. They completed three consecutive sessions: a 20-min quiet period as a baseline, a 30-min mental task period with general speakers or parametric speakers, and a 20-min recovery period. We measured salivary cortisol and chromogranin A (CgA) concentrations. Furthermore, subjects took the Kwansei-gakuin Sleepiness Scale (KSS) test before and after the task and also a sound quality evaluation test after it. Four experiments, one with a speaker condition (general speaker and parametric speaker), the other with a distance condition (0.3 m and 1.0 m), were conducted, respectively, at the same time of day on separate days. We used three-way repeated measures ANOVA (speaker factor × distance factor × time factor) to examine the effects of the parametric speaker. RESULTS: We found that the endocrinological functions were not significantly different between the speaker condition and the distance condition. CONCLUSION: The results also showed that the physiological burdens increased with progress in time independent of the speaker condition and distance condition.

The effects of parametric speaker sound on salivary hormones and a subjective evaluation.

OBJECTIVE: Recently, a parametric speaker system has been developed. However, the safety of the parametric speaker for the human body has not yet been demonstrated. Therefore, we studied the effects of parametric speaker sound on salivary hormones and carried out a subjective evaluation. METHODS: Nine male subjects participated in this study. They completed three consecutive sessions: a 20-min quiet period as a baseline, a 45-min mental task period with either a general or parametric speaker, and a 20-min recovery period. The subjects were evaluated by the salivary cortisol and chromogranin A (CgA) concentrations. In addition, they took the Kwansei-Gakuin sleepiness scale (KSS) test before and after the task and also a sound quality evaluation test after it. Two experiments, one with a general speaker (general condition) and the other with a parametric speaker (parametric condition), were conducted at the same time of day on separate days. To examine the effects of the parametric speaker, a two-way repeated measures ANOVA (speaker factor and time factor) was conducted. RESULTS: The results showed that the cortisol concentration was significantly lower during the parametric condition than during the general condition. Furthermore, the sound quality evaluation found a "warm" sensation during the parametric condition to be lower than that during the general condition. A "noisy" sensation during the parametric condition tended to be higher than during the general speaker. However, the CgA concentration and the KSS score were not significantly different for either the speaker factor or the time factor. CONCLUSION: The results suggested that the burden of the parametric speaker was smaller than that of general speaker, especially on the HPA-axis in the endocrine system.

Recombinant human BMP-2 accelerates the migration of bone marrow mesenchymal stem cells via the CDC42/PAK1/LIMK1 pathway in vitro and in vivo.

Biomaterials are widely used for bone regeneration and fracture repair. The migration of bone marrow mesenchymal stem cells (BMSCs) into bone defect sites or material implantation sites, and their differentiation into osteoblasts, is central to the fracture healing process, and the directional migration of BMSCs depends on cytokines or chemokines at the defect site. BMP-2 can stimulate the migration of a variety of cells, but it remains unclear whether BMSC migration can be induced. To provide evidence for BMP-2-induced BMSC migration, we tested the cytoskeletal changes and migration ability of BMSCs after treatment with recombinant human BMP-2 (rhBMP-2). We also explored the recruitment of BMSCs from the circulatory system using a collagen sponge incorporating rhBMP-2 that was implanted in vivo. Furthermore, to understand the mechanism underlying this migration, we investigated the effect of rhBMP-2 on migration-related signal pathways. Here, we found that, rhBMP-2 treatment significantly increased the migration of BMSCs in vitro via activation of the CDC42/PAK1/LIMK1 pathway, and that this migration could be blocked by silencing CDC42. In vivo, collagen sponge material loaded with rhBMP-2 could recruit BMSCs injected into the circulatory system. Moreover, inhibition using the small interfering RNA for CDC42 led to a significant decrease in the number of BMSCs within the material. In conclusion, our data prove that rhBMP-2 can accelerate BMSC migration via the CDC42/PAK1/LIMK1 pathway both in vivo and in vitro, and therefore provides a foundation for further understanding and application of rhBMP-2-incorporated materials by enhancing BMSC recruitment.

MnO2-deposited lignin-based carbon nanofiber mats for application as electrodes in symmetric pseudocapacitors.

Low-cost, high-performance electrodes are highly attractive for practical supercapacitor applications. MnO2-deposited carbon nanofiber mats (MnO2-CNFMs) are prepared for use as binder-free supercapacitor electrodes. MnO2 is deposited on the mats in situ by hydrothermally decomposing aqueous KMnO4, leading to the formation of nanocrystals of MnO2. The MnO2-CNFM electrode produced with 38.0µmol KMnO4 (this electrode) shows a high specific capacitance of ~171.6F·g-1 at a scan rate of 5mV·s-1. Moreover, a symmetric supercapacitor with the electrode exhibits a specific capacitance of 67.0F·g-1, an energy density of 6.0Wh·kg-1 and a power density of 160W·kg-1 at a special current of 0.1A·g-1. Further, the symmetric supercapacitor displays excellent cycling stability, retains approximately 99% of the capacitance after 1000cycles. The simplicity and ease of preparation of the MnO2-CNFMs as well as their suitability for use in coin-type supercapacitor cells make them ideal for application in cost-effective and high-performance electrodes for supercapacitors.

Characterization of carbon nanofiber mats produced from electrospun lignin-g-polyacrylonitrile copolymer.

The graft copolymerization of acrylonitrile (AN) onto methanol-soluble kraft lignin (ML) was achieved through a two-step process in which AN was first polymerized with an α,α'-azobisisobutyronitrile initiator, followed by radical coupling with activated ML. A carbon nanofiber material was obtained by electrospinning a solution of this copolymer in N,N-dimethylformamide, then subjecting it to a heat treatment including thermostabilization at 250°C and subsequent carbonization at 600-1400°C. Increasing the carbonization temperature was found to increase the carbon content of the resulting carbon nanofibers from 70.5 to 97.1%, which had the effect of increasing their tensile strength from 35.2 to 89.4 MPa, their crystallite size from 13.2 to 19.1 nm, and their electrical conductivity from ∼0 to 21.3 Scm(-1). The morphology of the mats, in terms of whether they experienced beading or not, was found to be dependent on the concentration of the initial electrospinning solution. From these results, it is proposed that these mats could provide the basis for a new class of carbon fiber material.

Optimizing the torrefaction of mixed softwood by response surface methodology for biomass upgrading to high energy density.

The optimal conditions for the torrefaction of mixed softwood were investigated by response surface methodology. This showed that the chemical composition of torrefied biomass was influenced by the severity factor of torrefaction. The lignin content in the torrefied biomass increased with the SF, while holocellulose content decreased. Similarly, the carbon content energy value of torrefied biomass ranged from 19.31 to 22.12 MJ/kg increased from 50.79 to 57.36%, while the hydrogen and oxygen contents decreased. The energy value of torrefied biomass ranged from 19.31 to 22.12 MJ/kg. This implied that the energy contained in the torrefied biomass increased by 4-19%, when compared with the untreated biomass. The energy value and weight loss in biomass slowly increased as the SF increased up until 6.12; and then dramatically increased as the SF increased further from 6.12 to 7.0. However, the energy yield started decreasing at SF value higher than 6.12; and the highest energy yield was obtained at low SF.

Modeling to predict growth/no growth boundaries and kinetic behavior of Salmonella on cutting board surfaces.

This study developed models to predict the growth probabilities and kinetic behavior of Salmonella enterica strains on cutting boards. Polyethylene coupons (3 by 5 cm) were rubbed with pork belly, and pork purge was then sprayed on the coupon surface, followed by inoculation of a five-strain Salmonella mixture onto the surface of the coupons. These coupons were stored at 13 to 35°C for 12 h, and total bacterial and Salmonella cell counts were enumerated on tryptic soy agar and xylose lysine deoxycholate (XLD) agar, respectively, every 2 h, which produced 56 combinations. The combinations that had growth of ≥0.5 log CFU/cm(2) of Salmonella bacteria recovered on XLD agar were given the value 1 (growth), and the combinations that had growth of <0.5 log CFU/cm(2) were assigned the value 0 (no growth). These growth response data from XLD agar were analyzed by logistic regression for producing growth/no growth interfaces of Salmonella bacteria. In addition, a linear model was fitted to the Salmonella cell counts to calculate the growth rate (log CFU per square centimeter per hour) and initial cell count (log CFU per square centimeter), following secondary modeling with the square root model. All of the models developed were validated with observed data, which were not used for model development. Growth of total bacteria and Salmonella cells was observed at 28, 30, 33, and 35°C, but there was no growth detected below 20°C within the time frame investigated. Moreover, various indices indicated that the performance of the developed models was acceptable. The results suggest that the models developed in this study may be useful in predicting the growth/no growth interface and kinetic behavior of Salmonella bacteria on polyethylene cutting boards.

Effect of essential inorganic metals on primary thermal degradation of lignocellulosic biomass.

This study employed thermogravimetric analysis (TGA) and analytical Py-GC/MS in order to examine the catalytic effect of main inorganic metals (K, Mg and Ca) on the thermal degradation and the formation of pyrolytic products in lignocellulosic biomass. In addition, potential mechanisms of the primary pyrolysis in presence of the inorganic metals were derived. TG analysis showed that when potassium content increased in the biomass, char formation increased from 10.5 wt.% to 19.6 wt.% at 550 °C, and temperatures at which the maximum degradation rate was achieved shifted from 367 °C to 333 °C. With increasing magnesium content, the maximum degradation rate increased from 1.21 wt.%/°C to 1.43 wt.%/°C. Analytical Py-GC/MS revealed that potassium had a distinguished catalytic effect promoting the formation of low molecular weight compounds and suppressing the formation of levoglucosan. An increase in the yield of C6 and C2C6 lignin derivatives with increasing potassium content was also observed.

Characterization of primary thermal degradation features of lignocellulosic biomass after removal of inorganic metals by diverse solvents.

Poplar wood powders were treated with distilled water, tap water, HCl and HF, respectively, to remove inorganics from the biomass and to investigate effect of demineralization processes on pyrolysis behavior of the biomass. TG and DTG revealed that maximum degradation temperatures rose slightly from 362°C for control to 372°C, 366°C and 368°C after demineralization with distilled water, HCl and HF, respectively. Maximum degradation rates also increased from 0.96%/°C for control to 1.15%/°C for HF-biomass, 1.23%/°C for DI-H(2)O-biomass, and 1.55%/°C for HCl-biomass. Analytical pyrolysis-GC/MS of demineralized biomasses produced approximately 45 pyrolysis compounds. Total amount of low molecular weight compounds, such as acetic acid, acetol, and 3-hydroxypropanal, was significantly lowered in the demineralized biomasses. But levoglucosan increased 2-10-folds in the demineralized biomasses. One of the features regarding lignin derivatives was the reduction of the amount of C6-type phenols, such as phenol, guaiacol, and syringol after demineralization.

Complexin and Ca2+ stimulate SNARE-mediated membrane fusion.

Ca(2+)-triggered, synchronized synaptic vesicle fusion underlies interneuronal communication. Complexin is a major binding partner of the SNARE complex, the core fusion machinery at the presynapse. The physiological data on complexin, however, have been at odds with each other, making delineation of its molecular function difficult. Here we report direct observation of two-faceted functions of complexin using the single-vesicle fluorescence fusion assay and EPR. We show that complexin I has two opposing effects on trans-SNARE assembly: inhibition of SNARE complex formation and stabilization of assembled SNARE complexes. Of note, SNARE-mediated fusion is markedly stimulated by complexin, and it is further accelerated by two orders of magnitude in response to an externally applied Ca(2+) wave. We suggest that SNARE complexes, complexins and phospholipids collectively form a complex substrate for Ca(2+) and Ca(2+)-sensing fusion effectors in neurotransmitter release.