Electron localization in niobium doped CaMnO3 due to the energy difference of electronic states of Mn and Nb.

The electron localization in Nb-doped CaMnO3 is analyzed in terms of the space and energy distribution of electronic states employing first-principles calculations. The energy difference of Mn 3d states and Nb 4d states makes NbO6 octahedra impede electrical conduction, so the random distribution of Nb in lattices leads to the localization of electrons near the bottom of the conduction bands. Therefore, although more carriers are introduced when Nb-doping content increases, both the electrical conductivity and absolute thermopower decrease in Nb heavy doped CaMnO3. The calculated transport properties agree well with the experimental data, supporting the analysis of localization.

Dibutyl Phthalate Inhibits the Effects of Follicle-Stimulating Hormone on Rat Granulosa Cells Through Down-Regulation of Follicle-Stimulating Hormone Receptor.

Dibutyl phthalate (DBP) is used worldwide in solvents and plasticizers. The cytotoxicity and potential tumorigenic effect of DBP have been reported. DBP has also been shown to impact reproductive function. In this study, to further evaluate the effects of DBP on granulosa cells (GCs), we treated rat GCs in vitro with DBP before evaluation of the biological alterations of these GCs. We found that DBP did not induce significant GC death at the tested concentrations. However, follicle-stimulating hormone (FSH)-induced KIT ligand (KITLG) expression in GCs was significantly reduced at both mRNA and protein levels by DBP treatment in a dose-dependent manner. The down-regulation of KITLG was due to the down-regulation of expression of FSH receptor (FSHR) in GCs. Down-regulation of FSHR impaired FSH-induced intracellular signaling in GCs, demonstrated by decreased phosphorylation of AKT and mechanistic target of rapamycin (mTOR). Furthermore, DBP treatment also reduced FSH-induced expression of hypoxia-inducible factor 1-alpha (HIF1A), which is an important signaling component for KITLG expression. Other FSH-induced biological effects, such as production of estradiol and progesterone, as well as GC proliferation, were also suppressed by DBP. Therefore, our study discovered a unique mechanism underlying the toxicity of DBP on GCs. These findings may initiate the development of novel therapeutic interventions for DBP-induced damage to GCs.

Raman and Visible-Near Infrared Spectra of Cu(InGa)Se2 Films.

Cu(InxGa1-x)Se2(CIGS) precursor films were prepared on ITO glass with potentiostatic electrodeposition. High quality CIGS films were obtained by selenization of the precursor films at high temperature in tubular furnace full of argon gas. X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-Vis-NIR spectroscopy were used to characterize the structure, morphology, composition and Vis-NIR absorption of CIGS films, respectively. XRD results show the selenized CIGS films have a preferential orientation (112) with average crystallite of 24.7 nm. Raman spectroscopy reveals that the CIGS films are pure quaternaryphases with chalcopyrite structure, and without binary or ternary phases in the films. Vis-NIR measurements determine that the bandgap of CIGS increases with the increase of Ga concentration in the film. When the Ga concentration is 5.41%, its bandgap is about 1.11 eV, and the calculated ratio of Ga to (Ga+In) is 16.3%, which is less than the ratio of Ga to (Ga+In), 21.4%, measured by SEM. This indicates that crystallinity of CIGS filmsneeds to be further improved. All the measurements demonstratethat optimum ITO/CIGS has a promising application in bifacial solar cells. In this paper, we provide a newmethodtoelectrodeposit low cost CIGS precursor films and a new method forselenization ofthe precursor films at high temperature. As a result, theuniform and compact CIGS films with good adhesion on ITO are successfully fabricated by these methods. The above characterization show that we have obtained CIGS films with high crystallinity, near stoichiometry, few impurity phases and superior light absorption. Electrodeposition, like magnetron sputtering, is very suitable for large-scale industrial production. The research work in this paper is therefore important and considerable to massive production of electrodeposition of CIGS films.

Effects of fluoride-ion-implanted titanium surface on the cytocompatibility in vitro and osseointegatation in vivo for dental implant applications.

As an attractive technique for the improvement of biomaterials, Plasma immersion ion implantation (PIII) has been applied to modifying the titanium material for dental implant application. The present study investigated the cytocompatibility and early osseointegration of fluoride-ion-implanted titanium (F-Ti) surface and implants, both characterizing in their composition of titanium oxide and titanium fluoride. The cytocompatibility of F-Ti was evaluated in vitro by using scanning electron microscope, Cell Counting Kit-8 assay, alkaline phosphatase activity assay, and quantitative real-time polymerase chain reaction. The results showed that the F-Ti weakened the effects that Porphyromonas gingivalis exerted on the MG-63 cells in terms of morphology, proliferation, differentiation, and genetic expression when MG-63 cells and Porphyromonas gingivalis were co-cultured on the surface of F-Ti. Meanwhile, the osteogenic activity of F-Ti implants was assessed in vivo via evaluating the histological morphology and estimating histomorphometric parameters. The analysis of toluidine blue staining indicated that the new bone was more mature in subjects with F-Ti group, which exhibited the Haversian system, and the mean bone-implant contact value of F-Ti group was slightly higher than that of cp-Ti group (p>0.05). Fluorescence bands were wider and brighter in the F-Ti group, and the intensity of fluorochromes deposited at the sites of mineralized bone formation was significantly higher for F-Ti surfaces than for cp-Ti surfaces, within the 2nd, 3rd and 4th weeks (p<0.05). An indication is that the fluoride modified titanium can promote cytocompatibility and early osseointegration, thus providing a promising alternative for clinical use.

High in vitro antibacterial activity of Pac-525 against Porphyromonas gingivalis biofilms cultured on titanium.

In order to investigate the potential of short antimicrobial peptides (AMPs) as alternative antibacterial agents during the treatment of peri-implantitis, the cytotoxic activity of three short AMPs, that is, Pac-525, KSL-W, and KSL, was determined using the MTT assay. The antimicrobial activity of these AMPs, ranging in concentration from 0.0039 mg/mL to 0.5 mg/mL, against the predominant planktonic pathogens, including Streptococcus sanguis, Fusobacterium nucleatum, and Porphyromonas gingivalis, involved in peri-implantitis was investigated. Furthermore, 2-day-old P. gingivalis biofilms cultured on titanium surfaces were treated with Pac-525 and subsequently observed and analysed using confocal laser scanning microscopy (CLSM). The average cell proliferation curve indicated that there was no cytotoxicity due to the three short AMPs. The minimum inhibitory concentration and minimum bactericidal concentration values of Pac-525 were 0.0625 mg/mL and 0.125 mg/mL, respectively, for P. gingivalis and 0.0078 mg/mL and 0.0156 mg/mL, respectively, for F. nucleatum. Using CLSM, we confirmed that compared to 0.1% chlorhexidine, 0.5 mg/mL of Pac-525 caused a significant decrease in biofilm thickness and a decline in the percentage of live bacteria. These data indicate that Pac-525 has unique properties that might make it suitable for the inhibition the growth of pathogenic bacteria around dental implants.

Polymorphism in the hypoxia-inducible factor 1alpha gene may confer susceptibility to LDD in Chinese cohort.

OBJECTIVE: This study aimed to investigate whether or not hypoxia-inducible factor-1α (HIF-1α) gene variants are associated with the susceptibility and clinical characteristics of lumbar disc degeneration (LDD). METHODS: We examined 320 patients with LDD and 447 gender- and age-matched control subjects. We also determined the HIF-1α gene variants, including C1772T (P582S) and G1790A (A588T) polymorphisms. RESULTS: Significant differences were observed in allelic and genotypic distributions of 1790 A > G polymorphisms between LDD cases and control subjects. Logistic regression revealed that 1790 AA genotypes indicated a protective effect against the development of LDD. The HIF-1α 1790 A > G polymorphisms also affected the severity of LDD as evaluated based on the modified Japanese Orthopedic Association (mJOA) scores. The 1790 AA genotype carriers exhibited significantly lower mJOA scores than AG and GG carriers. C1772T did not show any association with the risk and severity of LDD. CONCLUSION: Our study suggested that HIF-1α 1790 A > G polymorphisms may be used as a molecular marker to determine the susceptibility and severity of LDD.

[Comparative study on thin films of cadmium sulfide prepared by chemical bath deposition and radio frequency magnetron sputtering].

Thin films of cadmium sulfide (CdS) were prepared with ammonium chloride, cadmium chloride, potassium hydroxide and thiourea by chemical bath deposition (CBD). For comparison, CdS films were also deposited by radio frequency (RF) magnetron sputtering, using CdS and argon as a target and reactive gas, respectively. The films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and ultraviolet-visible spectroscopy. The results show that the CdS films prepared by the above two methods have (002) orientation, the CdS films deposited by RF magnetron sputtering are more compact and much smoother than those prepared by CBD, and have lager crystalline size of about 20-30 nm. The CdS films prepared by CBD have smaller crystalline size and more defects. The properties of CdS thin films prepared by RF magnetron sputtering are totally superior to those of CdS films by CBD, but the optical transmittance of CdS thin films at short wavelength is an exception. The energy gap of CdS films prepared by the two methods are all in the range of 2.3-2.5 eV.

Fast preparation of polystyrene-based monolith using microwave irradiation for micro-column separation.

The conventional analytical HPLC was successfully developed for micro-column separation by using a simple eluate splitting system, a self-preparation of monolithic column and an on-capillary column detector in our laboratory. A typical polystyrene-based monolith was quickly prepared inside the fused-silica capillary, which in situ polymerization was carried out in 10 min by microwave irradiation. The reactant solution consisted of styrene (ST) as a functional monomer, divinylbenzene (DVB) as a cross-linking agent, toluene and isooctane as porogenic solvents, and azobisisobutyronitrile (AIBN) as an initiator. The monolith was proved to form in the center of the capillary and adhered to the column inner wall by the scanning electron micrograph. Its chromatographic behaviors were evaluated in detail by varying the flow rate and percentage of mobile phases, and under the optimal condition, baseline separation of the model analytes including thiourea, benzene, toluene, ethylbenzene was obtained with a highest theoretical plate number near 11,290 N/m by the developed capillary HPLC. Furthermore, the stability and porosity of the prepared monolith were systematically investigated by a simple flow method.

[Influence of fluoride ion-implanted titanium on the formation of focal adhesion plaque in vitro].

OBJECTIVE: To evaluate the chemical composition of the modified surface of fluoride ion-implanted titanium and assess the effect on the formation of focal adhesion plaque in vitro. METHODS: Pure commercial titanium discs were treated with fluoride ion implantation by plasma immersion ion implantation technique (PIII) and chemical composition and value of the surface modification layer were characterized by X-ray photoelectron spectrometer (XPS). In order to investigate the formation of focal adhesion plaque, MG-63 cells were seeded onto the surfaces of the modified Ti discs and quantified by morphometric analysis using an immunofluorescence microscope. RESULTS: The full range XPS spectra and fitting results indicated that the surface of fluoride ion-implanted titanium was the mixture of titanium dioxide and titanium trifluoride. Meanwhile, the quantity of focal adhesion plaque on fluoride ion-implanted titanium was more than that on the non-implanted titanium after 6 hours' cell culture. CONCLUSION: The XPS data revealed that the modified surface layer of fluoride ion-implanted titanium contained titanium dioxide and titanium trifluoride, which could enhance the formation of focal adhesion plaque.

[Effects of mechanical stress on the formation and expression of Cbfalpha1 in vitro].

OBJECTIVE: To evaluate the effects of mechanical stress on the formation and expression of core binding factor alpha1 (Cbfalpha1) in MG-63 cells cultured on titanium in vitro. METHODS: MG-63 cells cultured on the titanium were subjected to a centrifugal force (2.205 N) 15 min per 4 hours and collected after 4, 8 and 12 hours. The formation and expression of Cbfalpha1 were examined by immunofluorescence staining and reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: Both the cells with or without centrifugal force created the fluorescence in the nucleus and the immunofluorescence intensity of Cbfalpha1 in MG-63 cells with centrifugal force were higher than those without centrifugal force (P<0.05). Meanwhile, both the cells with or without centrifugal force expressed the mRNA of Cbfalpha1 and the relative mRNA level of Cbfalpha1 in MG-63 cells with centrifugal force were higher than those without centrifugal force, and the differences were great significant (P<0.05). CONCLUSION: Mechanical stress are beneficial to the formation and expression of Cbfalpha1.

[Research on optical property of phase transition VO2 films].

Optical transmission spectra of VO2 films on glass, fused silica, and sapphire were recorded and analyzed during heating process. Thermally induced phase transition of VO2 films occurred at a certain temperature, associated with abrupt changes in optical properties. The transition temperature and the contrast of the optical properties depended on the substrate and the deposit method used. The change in transmittance delta T at 5 microns of VO2 films deposited on sapphire by RF magnetron sputtering was 70%, and the corresponding relative change delta T/TRT was 94%. For the VO2 films deposited on glass by RF magnetron sputtering, delta T at 2.5 microns was 64.2%, and delta T/TRT was as high as 98%.

[Three dimensional finite element stress analysis on superstructure of the fixed bridge supported by tooth-implant].

OBJECTIVE: To reveal the stress distribution in the superstructure of fixed bridge supported by tooth-implant in the process of mastication for improvement of denture design. METHODS: The stress distribution and displacement of the superstructure were studied and analyzed by means of CT Scan, CAD and three-dimensional finite element when various loads were applied. RESULTS: (1) The stress distribution in abutments under oblique loads at forty-five degrees was uneven and the peak value was 4 - 6 times higher than that under vertical loads. Stress concentration occurred with significant compressive stress. (2) Compressive stress widely distributed in the middle area of occlusal surface of pontic, whose peak value under concentrated loads was significantly higher than that under disperse loads. The loading direction had no effect on the stress concentration. (3) The maximum displacement of implant abutment in medial-distal direction was greater than that of the neck of nature tooth. CONCLUSIONS: The mechanic complications of superstructure could be prevented by reducing oblique loads and concentrated ones. It is certain that the further improvements of curve-resistance of pontics and press-resistance of abutments are available.