Milling properties of low temperature sintered zirconia blocks for dental use.

To investigate the milling properties of different yttria-tetragonal zirconia polycrystalline (Y-TZP) block materials by applying a dental computer numerical control (CNC) milling center. Low temperature sintering zirconia block denoted by KMUZ (experimental) with two commercial zirconia blocks for T block made in Taiwan and a G block made in Germany were compared for the milling properties. Seventy-two specimens were milled using the same CNC milling center, and properties were evaluated by measuring the weight loss (g), milling time (s), margin integrity (%) and broken diameter (µm). The crystalline phases contents were identified by X-ray diffraction and the microstructures of the sintering specimens were observed by scanning electron microscopy and transmission electron microscopy. The mean milling time of G and KMUZ were significantly shorter than T (P<0.05). The KMUZ samples exhibited the least weight loss among the three kinds of blocks (P<0.05). The percentages of marginal integrity after milling were high in G and KMUZ but low in T (P<0.05). The mean broken diameters were from 90µm to 120µm. The phase transformation of t-ZrO2 (KMUZ: 7.4%, G: 5.9%, T: 3.2%) to m-ZrO2 when facing the milling pressure in ZrO2 blocks was observed by XRD. The result of TEM microstructure of KMUZ revealed that Y and Si were soluble in grain boundaries. The results show that the milling properties of KMUZ were better than one commercial T and near the G. The hindered grain growth, as a result of the Y3+ content in the grain boundaries, also plays a role in promoting the abnormal grain growth of 3Y-TZP.

HPLC-fingerprints and antioxidant constituents of Phyla nodiflora.

Phyla nodiflora is a creeping perennial herb, widely distributed in the most tropical and subtropical regions. It has been used as a folk medicine, herbal beverage, or folk cosmetic. For these usages, the development of a chemical quality control method of this plant is necessary. In the present study, ten compounds, namely, 3,7,4',5'-tetrahydroxy-3'-methoxyflavone (1), nodifloretin (2), 4'-hydroxywogonin (3), onopordin (4), cirsiliol (5), 5,7,8,4'-tetrahydroxy-3'-methoxyflavone (6), eupafolin (7), hispidulin (8), larycitrin (9), and ß-sitosterol were isolated from the methanolic extract of the aerial part of P. nodiflora (PNM) and their structures were identified by 1D-NMR comparing their spectra with the literature. The antioxidant activities of these compounds were evaluated by free radical scavenging activity and tyrosinase inhibitory effect in cell-free systems. Compounds 4, 5, and 7 showed strong antioxidant activity. To control the quality of P. nodiflora, a simple and reliable method of high-performance liquid chromatography combined with ultraviolet detector (HPLC-UV) was established for both the fingerprint analysis and the quantitative determination of two selected active compounds, onopordin (4) and eupafolin (7). Statistical analysis of the obtained data demonstrated that our method achieved the desired linearity, precision, and accuracy. The results indicated that the developed method can be used as a quality evaluation method for PNM.

Eupafolin, a skin whitening flavonoid isolated from Phyla nodiflora, downregulated melanogenesis: Role of MAPK and Akt pathways.

ETHNOPHARMACOLOGICAL RELEVANCE: In hyperpigmentation disorders marked by melanin overproduction in the skin, including melisma and freckles, melanogenesis is caused by tyrosinase overexpression. Natural medicinal resources, like Phyla nodiflora, a traditional Chinese herbal medicine, have been used for a long time to management of dermatological conditions, such as skin inflammation and melanogenesis. Eupafolin, a functional flavonoid isolated from Phyla nodiflora, is an herbal tea constituent and possesses anti-inflammatory and anticancer activities. However, molecular mechanisms of eupafolin-mediated antimelanogenesis remain unknown. We thus focused on its antimelanogenesis effects in B16F10 mouse melanoma cells. MATERIAL AND METHODS: B16F10 cells were treated with eupafolin (0.01, 0.1, 1, and 10µM) in a dose-escalation-dependent manner for the determination of melanin, tyrosinase activity and melanogenesis protein levels by ELISA or western blot analysis. RESULTS: Eupafolin treatment significantly reduced cellular melanin content and tyrosinase activity in a dose-dependent manner (P<0.05), and no cytotoxic effects were observed. Eupafolin was associated with reduction in the levels of phospho-cAMP response element-binding protein and microphthalmia-associated transcription factor (MITF), and downregulation of tyrosinase synthesis and tyrosinase-related protein expression, leading to inhibit melanin production. In addition, eupafolin significantly induced the phosphorylation of ERK1/2 and p38 MAPK, whereas the decreased effect was observed in the phosphorylation of Akt. Moreover, inhibitors of these signals recovered or attenuated the inhibitory effects of eupafolin on melanogenesis. CONCLUSIONS: Our results seem that inhibition of Akt and activation of phospho-ERK or p38 MAPK may lead to the suppression of melanogenesis in eupafolin-treated B16F10 mouse melanoma cells.

The properties of sintered calcium phosphate with [Ca]/[P] = 1.50.

In order to obtain the properties of the sintered as-dried calcium phosphate with [Ca]/[P] = 1.50, the characteristics of sintered pellets have been investigated using X-ray diffraction (XRD), inductively coupled plasma-mass spectrometry (ICP-MS), Fourier-transform infrared (FT-IR) spectra, Vickers hardness indentation and scanning electron microscopy (SEM). When the pellet samples were sintered between 700 °C and 1200 °C for 4 h, the hydroxyapatite (Ca(10)(PO(4))(6)(OH)(2), HA) still maintained the major phase, accompanied with the rhenanite (NaCaPO(4)) as the secondary phase and ß-tricalcium phosphate (ß-Ca(3)(PO(4))(2), ß-TCP) as the minor phases. In addition, the HA partially transformed to α-tricalcium phosphate (α-Ca(3)(PO(4))(2), α-TCP) and tetracalcium phosphate (Ca(4)(PO4)(2)O, TTCP), when the pellet samples were sintered at 1300 °C and 1400 °C, respectively, for 4 h. The maximum density and Vickers Hardness (HV) of sintered pellet samples were 2.85 g/cm3 (90.18% theoretical density (T.D.)) and 407, which appeared at 1200 °C and 900 °C, respectively.

Preparation of TiO2 nanocrystallite powders coated with 9 mol% ZnO for cosmetic applications in sunscreens.

The preparation of TiO(2) nanocrystallite powders coated with and without 9 mol% ZnO has been studied for cosmetic applications in sunscreens by a co-precipitation process using TiCl(4) and Zn(NO(3))(2)·6H(2)O as starting materials. XRD results show that the phases of anatase TiO(2) and rutile TiO(2) coexist for precursor powders without added ZnO (T-0Z) and calcined at 523 to 973 K for 2 h. When the T-0Z precursor powders are calcined at 1273 K for 2 h, only the rutile TiO(2) appears. In addition, when the TiO(2) precursor powders contain 9 mol% ZnO (T-9Z) are calcined at 873 to 973 K for 2 h, the crystallized samples are composed of the major phase of rutile TiO(2) and the minor phases of anatase TiO(2) and Zn(2)Ti(3)O(8). The analyses of UV/VIS/NIR spectra reveal that the absorption of the T-9Z precursor powders after being calcined has a red-shift effect in the UV range with increasing calcination temperature. Therefore, the TiO(2) nanocrystallite powders coated with 9 mol% ZnO can be used as the attenuate agent in the UV-A region for cosmetic applications in sunscreens.

Melanogenesis Inhibitor(s) from Phyla nodiflora Extract.

Overexpression of tyrosinase can cause excessive production of melanin and lead to hyperpigmentation disorders, including melasma and freckles. Recently, agents obtained from plants are being used as alternative medicines to downregulate tyrosinase synthesis and decrease melanin production. Phyla nodiflora Greene (Verbenaceae) is used as a folk medicine in Taiwanese for treating and preventing inflammatory diseases such as hepatitis and dermatitis. However, the antimelanogenesis activity and molecular biological mechanism underlying the activity of the methanolic extract of P. nodiflora (PNM) have not been investigated to date. Our results showed that PNM treatment was not cytotoxic and significantly reduced the cellular melanin content and tyrosinase activity in a dose-dependent manner (P < 0.05). Further, PNM exhibited a significant antimelanogenesis effect (P < 0.05) by reducing the levels of phospho-cAMP response element-binding protein and microphthalmia-associated transcription factor (MITF), inhibiting the synthesis of tyrosinase, tyrosinase-related protein-1 (TRP-1), and TRP-2, and decreasing the cellular melanin content. Moreover, PNM significantly activated the phosphorylation of mitogen-activated protein kinases, including phospho-extracellular signal-regulated kinase, c-Jun N-terminal kinase, and phospho-p38, and inhibited the synthesis of MITF, thus decreasing melanogenesis. These properties suggest that PNM could be used as a clinical and cosmetic skin-whitening agent to cure and/or prevent hyperpigmentation.

Formation and morphology of Zn(2)Ti(3)O(8) powders using hydrothermal process without dispersant agent or mineralizer.

Synthesis of Zn(2)Ti(3)O(8) powders for attenuating UVA using TiCl(4), Zn(NO(3))(2)·6H(2)O and NH(4)OH as precursor materials by hydrothermal process has been investigated. The X-ray diffractometry (XRD) results show the phases of ZnO, anatase TiO(2) and Zn(2)Ti(3)O(8) coexisted when the zinc titanate powders were calcined at 600 °C for 1 h. When calcined at 900 °C for 1 h, the XRD results reveal the existence of ZnO, Zn(2)TiO(4), rutile TiO(2) and ZnTiO(3). Scanning electron microscope (SEM) observations show extensive large agglomeration in the samples. Transmission electron microscope (TEM) and electron diffraction (ED) examination results indicate that ZnTiO(3) crystallites formed with a size of about 5 nm on the matrix of plate-like ZnO when calcined at 700 °C for 1 h. The calcination samples have acceptable absorbance at a wavelength of 400 nm, indicating that the zinc titanate precursor powders calcined at 700 °C for 1 h can be used as an UVA-attenuating agent.