Preparation of matrix-matched standards for the analysis of teeth via laser ablation-inductively coupled plasma-mass spectrometry.

Mineralised tissue such as teeth can serve as a retrospective, chronological bioindicator of past exposure to toxic metals. Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) can be used to determine the presence and spatial distribution of toxic metals in teeth, giving a record of when an exposure occurred. Concentrations of these metals are often determined by a one-point calibration against NIST glass using an equation that requires an internal standard factor that accounts for differences in ablation behaviour between the glass and the tooth. However, an ideal external calibration would contain multiple matrix-matched standards to obtain a calibration curve. Here, we investigated optimal procedures for preparing synthetic hydroxyapatite (HA) doped with elements of interest as a calibration material. The materials were examined for homogeneity of metal incorporation, matrix-matched ablation characteristics, linearity, and limits of detection. A homogenised and pelleted HA was the most suitable material, providing improved ablation characteristics over previous HA materials and NIST glass for the analysis of teeth. An ablation yield of 1.1 showed its suitability to analyse teeth, the metals were homogeneously incorporated, and it produced excellent linearity with limits of detection ranging from 0.1-2 µg kg-1 for magnesium, aluminium, nickel, copper, zinc, cadmium, barium and lead. A juvenile incisor from a remote indigenous community in Australia and an adult molar from Sri Lanka were assessed for toxic metal exposure. The molar showed evidence of exposure to cadmium and lead. The synthetic HA material was straightforward to prepare, and will improve confidence in the analysis of teeth and other biomineralised material when assessing toxic metal exposure.

Factors influencing microgame adoption among secondary school mathematics teachers supported by structural equation modelling-based research.

Microgames are rapidly gaining increased attention and are highly being considered because of the technology-based media that enhances students' learning interests and educational activities. Therefore, this study aims to develop a new construct through confirmatory factor analysis, to comprehensively understand the factors influencing the use of microgames in mathematics class. Participants of the study were the secondary school teachers in West Java, Indonesia, which had a 1-year training in microgames development. We applied a quantitative approach to collect the data via online questionnaires through google form. Structural Equation Modelling (SEM) with AMOS software was used to analyze the proposed model. Empirical results confirmed the perceived easy to use and subjective norm influence (PEU and SN) relationship with teachers' microgame usage behaviors and intentions. In this condition, SN was found to have the initial significant influence on behavioral intention (BI), as attitude, BI, and facilitating conditions also correlated with the actual use of microgames. Furthermore, the largest influential factor was BI, with the results subsequently showing that TPACK had no significant influence on the actual use of microgames. This report is expected to help bridge the gap across several previous studies, as well as contribute to the explanation and prediction of the factors influencing the teachers' mathematical utilization of the study's program. Besides this, it also helps to increase the use of microgames in teaching and learning activities.

Macrophage Polarization is Deregulated in Haemophilia.

Macrophages make important contributions to inflammation and wound healing. We show here that macrophage polarization is deregulated in haemophilia in response to macrophage colony-stimulating factor (M-CSF) and partially in response to granulocyte-macrophage colony-stimulating factor (GM-CSF). As a result, haemophilia macrophages exhibit a specific impairment of M-CSF-mediated functions involved in wound healing such as clot invasion and phagocytosis. Haemophilia monocytes express reduced amounts of the receptors for M-CSF and GM-CSF, which correlates with a failure to express tumour necrosis factor α (TNFα) and CD163 in M-CSF-treated haemophilia macrophages and reduced expression of TNFα and CD206 after treatment with GM-CSF. Protein expression in response to M-CSF was regained with respect to CD163 and CD206 after embedding haemophilia monocytes in clotted plasma suggesting that a functioning coagulation system has positive effects on macrophage M2 polarization. Mimicking the functional deficits of haemophilia macrophages in normal macrophages was possible by adding leptin, which we found to be elevated in the blood of haemophilia patients, to a monocyte cell line. The increase of leptin occurred in conjunction with C-reactive protein in a body mass index-controlled cohort suggesting that haemophilia patients harbour chronic low-grade inflammation. Together, our data indicate that impaired clotting in haemophilia patients leads to increased inflammation and a deregulation in macrophage differentiation, which may explain the commonly observed deficits in wound healing and tissue regeneration.

Optical response of the Cu2 S2 diamond core in Cu2II(NGuaS)2 Cl2.

Density functional theory (DFT) and time-dependent DFT calculations are presented for the dicopper thiolate complex Cu2 (NGuaS)2 Cl2 [NGuaS=2-(1,1,3,3-tetramethylguanidino) benzenethiolate] with a special focus on the bonding mechanism of the Cu2 S2 Cl2 core and the spectroscopic response. This complex is relevant for the understanding of dicopper redox centers, for example, the CuA center. Its UV/Vis absorption is theoretically studied and found to be similar to other structural CuA models. The spectrum can be roughly divided in the known regions of metal d-d absorptions and metal to ligand charge transfer regions. Nevertheless the chloride ions play an important role as electron donors, with the thiolate groups as electron acceptors. The bonding mechanism is dissected by means of charge decomposition analysis which reveals the large covalency of the Cu2 S2 diamond core mediated between Cu dz2 and S-S π and π* orbitals forming Cu-S σ bonds. Measured resonant Raman spectra are shown for 360- and 720-nm excitation wavelength and interpreted using the calculated vibrational eigenmodes and frequencies. The calculations help to rationalize the varying resonant behavior at different optical excitations. Especially the phenylene rings are only resonant for 720 nm. © 2016 Wiley Periodicals, Inc.

A comprehensive LC/MS analysis of novel cyclopentenedione library.

Cyclopentenediones (CPDs) are compounds with a variety of applications ranging from the preparation of functional polymers to the development of antimicrobial agents, suggesting the potential use of CPDs as novel bioactive compounds or drugs. For this reason, a detailed characterization of CPDs and the development of robust analytical methods for their trace analysis are being sought. Here we focused on the design and synthesis of a library of novelized benzylidene CPD derivatives that were consequently characterized by ultra-high performance liquid chromatography (UHPLC) on-line connected with tandem mass spectrometry (MS/MS). The library design was based on a 2-benzylidene-4-cyclopentene-1,3-dione skeleton substituted with a variety of hydroxy, methoxy, halogen, linear aliphatic, heterocyclic and saccharide moieties, primarily modulating the skeleton's hydrophobicity. The prepared CPDs were effectively ionized by positive/negative atmospheric pressure photoionization (APPI) and atmospheric pressure chemical ionization (APCI). After careful optimization of the dopant composition and flow rate, positive-mode APPI proved to be more sensitive than APCI. In negative mode, both ionization techniques gave similar results. Further, a detailed MS fragmentation study was performed, confirming the structure of the compounds and enabling positional isomers of CPDs to be differentiated on the basis of their collision spectra analysis. Finally, an optimization of the composition of the mobile phase and reversed-phased separation mode were done, followed by a selection of the most suitable UHPLC stationary phases, i.e. C18, C8 and phenyl. The applicability of the method was evaluated by the inclusion of the other two substances in the study, i.e. monomeric and dimeric bioactive CPDs, compound TX-1123 and nostotrebin 6 with cytostatic and antimicrobial activities, respectively. The results presented here could be used in further investigations of the chromatographic retention and MS behavior of CPDs, which could be utilized for their isolation, detailed characterization and analysis in biological systems.