Effects of Lactiplantibacillus plantarum FBT215 and prebiotics on the gut microbiota structure of mice.

Imbalanced intestinal microbiota is associated with diseases, including inflammatory bowel disease and obesity, and diet can alter the structure of the gut microbiota. In this study, the effects of dietary treatments including the potential probiotic Lactiplantibacillus plantarum FBT215 with/without prebiotics on the intestinal microbiota composition of mice were investigated. Lactiplantibacillus plantarum FBT215 administration significantly decreased the Firmicutes/Bacteroidetes ratio and increased the abundance of Muribaculum and Duncaniella. The diversity within and between groups was measured according to α and ß diversity metrics, respectively. The Shannon index of α diversity decreased significantly in all treatment groups except the probiotic group, although this group showed an increase in the Chao1 index. Principal coordinate analysis of ß diversity showed that the groups had different species distributions. Finally, gamma-aminobutyric acid (GABA) concentration increased in groups fed L. plantarum FBT215. These findings improve our understanding of the association between the gut microbiota structure and specific probiotic/prebiotic-containing diets.

Effect of 9% Hydrofluoric Acid Gel Hot-Etching Surface Treatment on Shear Bond Strength of Resin Cements to Zirconia Ceramics.

Background and Objectives: There is no consensus regarding the surface treatment method for achieving optimal bonding strength between zirconia and resin cements. We evaluated the effect of hot-etching with 9% hydrofluoric acid (HF) gel using the Zirconia Etchant Cloud System on zirconia surfaces and the consequent shear bond strength (SBS) of different resin cements to such surface-treated zirconia ceramics. Materials and Methods: Forty-five zirconia specimens were randomly assigned to surface-treatment groups (n = 15/group): no treatment (control, CT); sandblasting with 110-µm Al2O3 at an air pressure of 1 bar for 10 s (SB); hot-etching with 9% HF gel (HE). Post-treatment, specimens were examined using scanning electron microscopy (SEM) and surface roughness (SR) analysis. After treatment, self-adhesive resin cements (Maxcem Elite, MAZIC Cem, RelyX U200, 3M ESPE: Maplewood, MN, USA) were bonded to zirconia specimens, which were stored in distilled water at 37 °C for 24 h. All specimens were then subjected to SBS testing, using a universal testing machine, until failure. Data were analyzed using one-way analysis of variance and Tukey's post hoc test (α = 0.05). Results: In the SEM images, roughness was greater in SB than in HE specimens. Ra and Rt values were highest in SB, followed by HE, and CT specimens. HE specimens showed significantly higher SBS values than CT or SB specimens (p < 0.05). MAZIC Cem cement, with 10-methacryloyloxydcyl dihydrogen phosphate yielded the highest SBS values. Conclusions: Hot-etching with 9% HF gel in a safe shell formed uniformly small, defined holes on the zirconia surface and achieved significantly higher SBS values than sandblasting (p < 0.05). Zirconia prostheses can be bonded micromechanically with resin cement, without the deterioration of properties due to t-m transformation, using chemical acid etching with the Zirconia Etchant Cloud System.

Probiotic Properties and Optimization of Gamma-Aminobutyric Acid Production by Lactiplantibacillus plantarum FBT215.

Gamma-aminobutyric acid (GABA) improves various physiological illnesses, including diabetes, hypertension, depression, memory lapse, and insomnia in humans. Therefore, interest in the commercial production of GABA is steadily increasing. Lactic acid bacteria (LAB) have widely been reported as a GABA producer and are safe for human consumption. In this study, GABA-producing LAB were preliminarily identified and quantified via GABase assay. The acid and bile tolerance of the L. plantarum FBT215 strain were evaluated. The one-factor-at-a-time (OFAT) strategy was applied to determine the optimal conditions for GABA production using HPLC. Response surface methodology (RSM) with Box-Behnken design was used to predict the optimum GABA production. The strain FBT215 was shown to be acid and bile tolerant. The optimization of GABA production via the OFAT strategy resulted in an average GABA concentration of 1688.65 ± 14.29 µg/ml, while it was 1812.16 ± 23.16 µg/ml when RSM was applied. In conclusion, this study provides the optimum culture conditions for GABA production by the strain FBT215 and indicates that L. plantarum FBT215 is potentially promising for commercial functional probiotics with health claims.

Gamma-aminobutyric acid fermentation in MRS-based medium by the fructophilic Lactiplantibacillus plantarum Y7.

Among the key metabolites produced by probiotic lactic acid bacteria (LAB), the use of gamma-aminobutyric acid (GABA), which alleviates hypertension, depression, and sleepiness in humans, is gaining popularity. Thus, GABA-producing LAB are sought after. GABA-producing LAB were preliminarily screened in acidified-MRS broth and quantified via GABase assays. The one-factor-at-a-time strategy was applied to determine the optimal conditions for GABA production. GABA production in reconstituted skim milk medium (RSM) and antibiotic susceptibility testing were performed to evaluate the potential of the strain as a yogurt starter. L. plantarum Y7 produced 4,856.86 ± 82.47 µg/mL of GABA at optimal culture conditions. Co-cultivation of Y7 and commercial Lactobacillus bulgaricus affected the amount of GABA production (6.85 ± 0.20 µg/mL) in RSM. Y7 was susceptible to ampicillin, erythromycin, and tetracycline. Therefore, L. plantarum Y7 represents a promising strain for GABA production in the food industry.

Improvement of SiC Crystal Growth Rate and Uniformity via Top-Seeded Solution Growth under External Static Magnetic Field: A Numerical Investigation.

Silicon carbide (SiC) is an ideal material for highpower and highperformance electronic applications. Topseeded solution growth (TSSG) is considered as a potential method for bulk growth of highquality SiC single crystals from the liquid phase source material. The crystal growth performance, such as growth rate and uniformity, is driven by the fluid flow and constitutional flux in the solution. In this study, we numerically investigate the contribution of the external static magnetic field generated by Helmholtz coils to the fluid flow in the silicon melt. Depending on the setup of the Helmholtz coils, four static magnetic field distributions are available, namely, uniform vertical upward/downward and vertical/horizontal cusp. Based on the calculated carbon flux coming to the crystal surface, the vertical downward magnetic field proved its ability to enhance the growth rate as well as the uniformity of the grown crystal.

The Effect of Co-Doping at the A-Site on the Structure and Oxide Ion Conductivity in (Ba0.5-xSrx)La0.5InO3-δ: A Molecular Dynamics Study.

A molecular dynamics simulation was used to investigate the structural and transport properties of a (Ba0.5-xSrx)La0.5InO3-δ (x = 0, 0.1, 0.2) oxygen ion conductor. Previous studies reported that the ionic conductivity of Ba-doped LaInO3 decreases because Ba dopant forms a narrow oxygen path in the lattice, which could hinder the diffusion of oxygen ions. In this study, we reveal the mechanism to improve ionic conductivity by Ba and Sr co-doping on an La site in LaInO3 perovskite oxide. The results show that the ionic conductivity of (Ba0.5-xSrx)La0.5InO3-δ increases with an increasing number of Sr ions because oxygen diffusion paths which contain Sr ions have a larger critical radius than those containing Ba ions. The radial distribution function (RDF) calculations show that the peak heights in compositions including Sr ions were lower and broadened, meaning that the oxygen ions moved easily into other oxygen sites.

Straight Long-Range Surface Plasmon Polariton Waveguides with a Gap.

In straight long-range surface plasmon polariton (LR-SPP) waveguides with a gap (G-SPPWs), an excited input SPP propagates, jump overs the gap with low coupling loss, and propagates again, despite a micrometers-long gap. The micrometers long gap can be filled with various materials to control the LR-SPP mode in the G-SPPWs. Here, the optical characteristics of fabricated 20-nm-thick G-SPPWs with a fixed 2 µm gap length are experimentally evaluated at a wavelength of 1.55 µm. The gap coupling losses in the G-SPPWs were determined to be less than ~0.22 dB for various widths of the SPP waveguide (SPPW) up to ~8 µm, and the insertion losses were determined to be less than ~0.89 dB for the same design range. A minimum insertion loss of ~0.45 dB was obtained from the G-SPPW with a fixed 2 µm gap length and a 7 µm SPPW width. In the 2.5-Gbps optical signal transmission experiment, the G-SPPW exhibits excellent eye opening and the G-SPPW transfers the carrier wave as well as the data signal. The G-SPPW has potential to serve as a new plasmonic modulation element offering control of the guided SPP through interaction with an applied force in the gap.

Tapered Long-Range Surface Plasmon Polariton Waveguides with a Gap.

We propose tapered long-range surface plasmon polariton (LR-SPP) waveguides with a gap (tapered G-SPPWs) for improved tunneling efficiency in G-SPPWs. The optical characteristics of the fabricated tapered G-SPPWs were experimentally measured and compared with simulation results. The proposed tapered structure can improve tunneling efficiency by reducing insertion loss of the tapered G-SPPWs. The insertion losses of the straight G-SPPW with an 8-µm gap length and a 2-µm SPPW width and the tapered G-SPPW with an 8-µm gap length, a 2-µm SPPW width, a 6-µm taper width, and a 3-µm taper length were measured to be ~1.03 and ~0.74 dB, respectively. The tapered G-SPPW has potential as an efficient plasmonic modulation device element, offering control of the guided SPP through interaction with an applied force in the gap.

Flow modification enhancing the growth rate in top seeded solution growth of SiC crystals.

In this study, multiphysics simulations were carried out to understand the convection mechanisms of the top seeded solution growth (TSSG) of SiC. Experimental melting tests and crystal growth were conducted to verify the simulation results in the growing temperatures between 1700 and 1900 °C with rf induction heating furnace. From the solidified melt of Si-Cr solution after the melting test, the melt flow in the simulation was successfully verified. In the given experimental conditions, the electromagnetic convection was found to govern the global fluid flow, while other mechanisms including the Marangoni convection, the buoyancy convection and the centrifugal forced convection influence the fluid flow near the crystal. Based on an understanding of the fluid flow obtained with the simulations, a structural flow modifier (FM) was applied to enhance the growth rate of the SiC crystal. The growth rates of SiC with/without FM were successfully estimated from simulations showing good agreements with the experimental values. After the experimental crystal growth using FM, a remarkable enhancement in the growth rate was found in an FM configuration, which suggests a way to improve the growth rate by the TSSG method based on the efficient use of the dissolved C in the melt.

The Effect of Fibronectin-Immobilized Microgrooved Titanium Substrata on Cell Proliferation and Expression of Genes and Proteins in Human Gingival Fibroblasts.

BACKGROUND: We aimed to determine the effect of fibronectin (FN)-immobilized microgrooved titanium (Ti) on human gingival fibroblast proliferation, gene expression and protein expression. METHODS: Photolithography was used to fabricate the microgrooved Ti, and amine funtionalization (silanization) was used for FN immobilization on titanium surfaces. Cell proliferation, gene expression and protein expression were analyzed, followed by multiple regression analysis for determining the influential factors on cell proliferation. RESULTS: FN-immobilized microgrooved Ti significantly enhanced the fibroblast proliferation in various timelines of culture, among which a burst of fivefold increase is induced at 96 h of culture compared to that on the control smooth Ti. We suggest a presence of the synergistic promotion effect of microgrooves and FN immobilization on fibroblast proliferation. Through a series of analyses on the expression of various genes and proteins involved in cell adhesion and proliferation, cyclin-dependent kinase 6, cyclin D1, integrin α5, oncogene c-Src, osteonectin, paxillin and talin-2 were determined as influential factors on promoting fibroblast proliferation induced by FN-immobilized microgrooved Ti. CONCLUSION: FN-immobilized microgrooved Ti can act as an effective surface for enhancing fibroblast proliferation, and can be used for promoting soft tissue response on the connective tissue attachment zone of biomaterial surfaces.

One-step growth of multilayer-graphene hollow nanospheres via the self-elimination of SiC nuclei templates.

We introduce a one-step growth method for producing multilayer-graphene hollow nanospheres via a high-temperature chemical vapor deposition process using tetramethylsilane as an organic precursor. When the SiC nuclei were grown under an excess carbon atmosphere, they were surrounded via desorption of the hydrocarbon gas species, and graphene layers formed on the surface of the SiC nuclei via the rearrangement of solid carbon during the heating and cooling. The core SiC nuclei were spontaneously removed by the subsequent thermal decomposition, which also supplied the carbon for the graphene layers. Hence, multilayer-graphene hollow nanospheres were acquired via a one-step process, which was simply controlled by the growth temperature. In this growth process, the SiC nuclei acted as both the template and carbon source for the formation of multilayer-graphene hollow nanospheres.

Crystal Structure and Photocatalytic Activity of Al-Doped TiO2 Nanofibers for Methylene Blue Dye Degradation.

Al-TiO2 nanofibers were prepared using a sol-gel derived electrospinning by varying the Al/Ti molar ratio from 0 to 0.73 to investigate the effect of Al doping on the crystal structure and the photocatalytic activity of Al-TiO2 for methylene blue (MB) degradation. XRD results indicated that as the Al/Ti molar ratio rose, crystal structure of Al-TiO2 was changed from anatase/rutile (undoped), anatase (0.07-0.18), to amorphous phase (0.38-0.73), which was confirmed by XPS and Raman analysis. The degradation kinetic constant increased from 7.3 x 10(-4) min(-1) to 4.5 x 10(-3) min(-1) with the increase of Al/Ti molar ratios from 0 to 0.38, but decreased to 3.4 x 10(-3) min(-1) when the Al/Ti molar ratio reached 0.73. The Al-TiO2 catalyst doped with 0.38 Al/Ti molar ratio demonstrated the best MB degradation. Experimental results indicated that the Al doping in Al-TiO2 was mainly attributed to the crystal structure of TiO2 and the photocatalytic degradation of MB.

Photocatalytic Activity of W-Doped TiO2 Nanofibers for Methylene Blue Dye Degradation.

Photocatalytic degradation of methylene blue (MB) in water was examined using W-doped TiO2 nanofibers prepared by a sol-gel derived electrospinning and subsequent calcination for 4 h at 550 degrees C. Different concentrations of W dopant in the range of 0 to 8 mol% were synthesized to evaluate the effect of W concentration on the photocatalytic activity of TiO2. XRD results indicated that the undoped TiO2 is composed of anatase and rutile phases. The rutile phase was transformed to anatase phase completely with the W doping. Among W-TiO2 catalysts, the 2 mol% W-TiO2 catalyst showed the highest MB degradation rate. The degradation kinetic constant increased from 1.04 x 10(-3) min(-1) to 3.54 x 10(-3) min(-1) with the increase of W doping from 0 to 2 mol%, but decreased down to 1.77 x 10(-3) min(-1) when the W content was 8 mol%. It can be concluded that the degradation of MB under UV radiation was more efficient with W-TiO2 catalysts than with pure TiO2-

Discontinuous Tapered Surface Plasmon Polariton Waveguides with Gap.

We investigate characteristics of discontinuous tapered surface plasmon polariton waveguides with a gap (DTG-SPPWs) to control a guided surface plasmon polariton (SPP) at a telecommunication wavelength of 1.55 µm. The DTG-SPPWs are composed of an input 2 µm-wide and 10 µm-long reverse tapered IMI-W (RT-IMI-W) and a 10 µm-long tapered and output 2 µm-wide IMI-W (T-IMI-W) with the 8 µm-long gap. The width and length of the tapered regions in the RT-IMI-W and the T-IMI-W were varied from 2 to 10 µm and 1 to 8 µm, respectively. Gold is used as the metal in the insulator-metal-insulator waveguides (IMI-Ws). The thickness of the gold strips is fixed with 20 nm. A low-loss polymer is used for the 30 µm-thick upper and lower cladding layers. The coupling losses of the DTG-SPPWs are less than 0.055 dB with an 8 µm-long gap and various taper widths up to 10 µm. The normalized transmissions (NTs) of the DTG-SPPWs are less than about -0.060 dB with various taper widths up to 10 µm. The NTs of the DTG-SPPWs are less than about -0.069 dB with various taper lengths up to 8 µm. The maximum NT of about -0.042 dB was obtained using the 6 µm-wide taper width and the 3 µm-long taper length in the DTG-SPPW. The DTG-SPPWs have potential as a new plasmonic modulation device via control of the guided SPP through interaction with an applied force in the gap.

Promotion of osteoblastic differentiation and osteogenic transcription factor expression on a microgroove titanium surface with immobilized fibronectin or bone sialoprotein II.

We demonstrate that a composite surface of microgroove titanium (Ti) with immobilized fibronectin (FN) or bone sialoprotein II (BSP2) promotes osteoblastic differentiation and osteogenic transcription factor expression in human bone marrow-derived mesenchymal stem cells (MSCs). Comparisons made between smooth microgrooves, microgrooves with silanization and microgrooves with matrix protein (FN or BSP2)-immobilization Ti surfaces revealed a significant promotion of in vitro osteogenic activity and osteoblastic differentiation at various timelines of culture. An even more significant increase was verified on microgrooves with a matrix protein-immobilization Ti surface in 28 d time-dependent gene expression of the main osteogenic transcription factors, such as ARF4, FRA1, RUNX2, and OSX. As a result, a synergestic effect regarding the promotion of osteogenic transcription factor expression and osteoblastic differentiation in the matrix protein-microgroove Ti composite surface was confirmed. From a multiple regression analysis using various timelines of osteogenic culture as independent variables, day 13 was verified as the most prominent influential timeline for the promotion of osteoblastic differentiation induced by the matrix protein-microgroove Ti composite surface. The FN- or BSP2-microgroove Ti composite surface resulting from silanization can strongly induce the promotion of osteoblastic differentiation in human MSCs. The proposed surface is expected to be useful in the development of a variety of osteogenic biomaterial surfaces.

Effect of topographical control by a micro-molding process on the activity of human Mesenchymal Stem Cells on alumina ceramics.

BACKGROUND: Numerous studies have reported that microgrooves on metal and polymer materials can affect cell adhesion, proliferation, differentiation and guidance. However, our knowledge of the cell activity associated with microgrooves on ceramics, such as alumina, zirconia, hydroxyapatite and etc, is very incomplete, owing to difficulties in the engraving of microgrooves on the hard surface of the base material. In this study, microgrooves on alumina were fabricated by a casting process using a polydimethylsiloxane micro-mold. The cell responses of Human Mesenchymal Stem Cells on the alumina microgrooves were then evaluated. RESULTS: Microgrooves on an alumina surface by micro-mold casting can enhance the adhesion, differentiation of osteoblasts as well as gene expression related to osteoblast differentiation. The ALP activity and calcium concentration of the cells on alumina microgrooves were increased by more than twice compared to a non-microgrooved alumina surface. Moreover, regarding the osteoblast differentiation of hMSCs, the expression of ALP, RUNX2, OSX, OC and OPN on the microgrooved alumina were all significantly increased by 1.5 ~ 2.5 fold compared with the non-microgrooved alumina. CONCLUSION: Altering the topography on alumina by creating microgrooves using a micro-molding process has an important impact on the behavior of hMSCs, including the adhesion, differentiation of osteoblasts and osteoblast-specific gene expression. The significant increase in hMSC activity is explained by the increasing of material transportation in parallel direction and by the extending of spreading distance in perpendicular direction.

Surface functionalization of microgrooved titanium with dual growth factor-releasing nanoparticles for synergistic osteogenic differentiation of human mesenchymal stem cells.

We demonstrate that dual release of bone morphogenic protein-2 (BMP-2) and insulin-like growth factor-1 (IGF-1) by catechol-functionalized adhesive polymer nanoparticles on microgrooved titanium (Ti) surface enhances in vitro osteoblastic differentiation of human mesenchymal stem cells (MSCs). The nanoparticles consisted of three distinct domains, surface Ti-adhesive catechol groups, anionic poly(L-aspartic acid) (PAsp) shells, and hydrophobic poly(L-phenylalanine) (PPhe) cores. The immobilization of the adhesive nanoparticles onto microgrooved Ti surface was verified using various surface analytical tools, such as field-emission scanning electron microscopy (Fe-SEM), X-ray photoelectron spectroscopy (XPS), contact angle measurement. The nanoparticles were immobilized both on the groove bottom surface and the ridge top surface with a similar anchoring density. A fluorescence microscope visualized that BMP-2 and IGF-1 of positive charges were efficiently loaded onto the negatively charged PAsp shells of immobilized nanoparticles. We confirmed the enhanced osteoblastic differentiation of MSCs by presenting the expression results of major osteoblast marker genes and proteins. In addition, overall significant correlations between the experimental results verified the validity of our study. The proposed combined surface of microgrooves and growth factor-releasing nanoparticles can be used as a strong osteogenic promoter on various biomaterial surfaces.

The impact of kidney transplantation on 24-hour ambulatory blood pressure in end-stage renal disease patients.

In this study, we prospectively investigated the impact of kidney transplantation (KT) on the status of hypertension, including circadian rhythm in end-stage renal disease (ESRD) patients. We performed 24-hour ambulatory blood pressure (BP) monitoring and office BP measurement in 48 patients before and 1 year after KT. According to the nocturnal reduction in systolic BP (ΔSBP), the patients were divided into dippers, non-dippers, and reverse dippers. After KT, the mean BP value in office BP and 24-hour ambulatory BP monitoring did not change, but the proportion of patients taking anti-hypertensive drugs and the pill number significantly decreased. In contrast, the mean ΔSBP significantly decreased, and the proportion of non-dippers and reverse dippers did not decrease. Decrease in ΔSBP after KT was associated with inferior allograft function during follow-up. Our study suggests that KT improved the overall BP level, but it did not affect abnormal circadian rhythm in ESRD patients.

Agraphia caused by acute right parietal infarction.

Injury in the dominant language hemisphere typically leads to agraphia, however we report a patient with agraphia after injury to the right angular gyrus. A 71-year-old Korean woman presented with the complaint of an inability to write for the last 7 days. The patient had been illiterate for most of her life, but had started learning to write Hangul, the Korean alphabet, at a welfare center 3 years ago. On language screening she was unable to write although she could read, and other language functions showed no abnormalities. Brain MRI showed acute infarction in the right angular gyrus. Her writing patterns displayed features of surface agraphia, indicative of phoneme-to-grapheme conversion with phonetic writing of targets. Additionally, she manifested visual errors. A functional MRI indicated that her left hemisphere was language dominant. This patient experienced agraphia resulting from pure impairment of visuo-constructive function after acute infarction in the right angular gyrus.

Gapped Surface Plasmon Polariton Waveguides for Plasmonic Signal Modulation Applications.

We investigate the characteristics of gapped surface plasmon polariton waveguides (G-SPPWs) to control a guided SPP through interaction with an applied force in the gap at a telecommunication wavelength of 1.55 µm. Gold is used as the metal in the insulator-metal-insulator waveguides (IMI-Ws). A low-loss polymer is used for the 30-µm-thick upper and lower cladding layers. The excited input SPPs propagate, jump over gaps with low coupling losses, and propagate again, even though there is a lengthy 12-µm-long gap in the G-SPPWs. The coupling loss is less than 0.05 dB for G-SPPWs with a gap up to 8-µm long, various widths up to 8 µm, and various thicknesses up to 50 nm. The normalized transmissions of the 2-µm-wide and 20-nm-thick G-SPPWs are less than -0.06 dB with various gap lengths up to 8 µm. The normalized transmissions of the 2-µm-long and 20-nm-thick G-SPPWs are less than -0.05 dB with various widths up to 8 µm. The normalized transmissions of the G-SPPWs that are 2-µm-wide and 2-µm-long are less than -0.27 dB for various thicknesses up to 50 nm. The maximum normalized transmission of -0.041 dB is obtained using the 2-µm-long, 2-µm-wide and 20-nm-thick G-SPPW. G-SPPWs have potential as a new plasmonic modulation device via control of the guided SPP through interaction with an applied force in the gap.