The representation of coupling interactions in the Material Properties Open Database (MPOD)

International audience; The Material Properties Open Database (MPOD, http//mpod.cimav.edu.mx) is a functional element of the web-based open databases system linked with crystallography. MPOD delivers single-crystal tensor properties in several representations, ranging from numerical matrices to 3D printing. Longitudinal moduli surfaces can be displayed in computers as well as in smart cell phones. Properties are stored as '.mpod' files. IUCr formatting standards (CIF) are followed. The original published paper containing the data is cited. Structural and experimental information is also registered and linked. 'Coupling properties', say piezo-effects and magnetoelectricity, represent interactions linking different subsystems in a material. Currently, piezoelectricity occupies a significant fraction of cases in MPOD. The implications of crystal symmetry in piezoelectricity are systematically taken into account. Matrices' elements and longitudinal moduli surfaces are checked for consistency with the Neumann principle. The inclusion of magnetoelectric axial tensors introduces exciting features into MPOD

32-Channel silicon strip detection module for combined X-ray fluorescence spectroscopy and X-ray diffractometry analysis

A compact detection module for the simultaneous measurement of XRF and XRD in portable analytical applications, in particular in the mining sector, is presented. The detector head is based on 32 silicon strip detectors, fabricated with a low-leakage technology by FBK and readout by two 16-channel low-noise CUBE charge-sensitive amplifiers. The design of the module and its characterization are reported. Multiple configurations are experimentally compared in terms of strip length, spacing, collimation and charge sharing effects. The optimal configuration for a strip length of 6 mm and pitch 0.2 mm is thus identified. It offers an energy resolution of better than 200 eV at 5.9 keV with moderate cooling (−10°C) and peaking time of 14 μs

Case Report: Filling Defect in Posterior Semicircular Canal on MRI With Balanced Steady-State Gradient-Echo Sequences After Labyrinthine Ischemia in the Common Cochlear Artery Territory as an Early Sign of Fibrosis

We describe a rare case of posterior semicircular canal (PSC) fibrosis following acute labyrinthine ischemia in the territory supplied by the common cochlear artery (CCA) and review the relevant literature. A 71-year-old man with multiple vascular risk factors presented 12 days after the onset of acute vertigo and profound left-sided hearing loss. Right-beating spontaneous nystagmus with downbeat components elicited by mastoid vibrations and headshaking was detected. The video head impulse test (vHIT) revealed an isolated hypofunction of the left PSC, whereas vestibular evoked myogenic potentials (VEMPs) showed ipsilateral saccular loss. The clinical presentation and instrumental picture were consistent with acute ischemia in the territory supplied by left CCA. Compared to previous imaging, a new MRI of the brain with 3D-FIESTA sequences highlighted a filling defect in the left PSC, consistent with fibrosis. Hearing function exhibited mild improvement after steroid therapy and hyperbaric oxygen sessions, whereas vHIT abnormalities persisted over time. To the best of our knowledge, this is the only case in the literature reporting a filling defect on MRI, consistent with semicircular canal fibrosis following acute labyrinthine ischemia. Moreover, PSC fibrosis was related with poor functional outcome. We therefore suggest using balanced steady-state gradient-echo sequences a few weeks following an acute lesion of inner ear sensors to detect signal loss within membranous labyrinth consistent with post-ischemic fibrosis. Besides addressing the underlying etiology, signal loss might also offer clues on the functional behavior of the involved sensor over time. In cases of acute loss of inner ear function, a careful bedside examination supplemented by instrumental assessments, including vHIT and VEMPs, of vestibular receptors and afferents may be completed by MRI with balanced steady-state gradient-echo sequences at a later time to confirm the diagnosis and address both etiology and functional outcome

Solid phase epitaxial re-growth of Sn ion implanted germanium thin films

Doping of Ge with Sn atoms by ion implantation and annealing by solid phase epitaxial re-growth process was investigated as a possible way to create GeSn layers. Ion implantation was carried out at liquid nitrogen to avoid nano-void formation and three implant doses were tested: 5×10, 1×10 and 5×10 at/cm, respectively. Implant energy was set to 45 keV and implants were carried out through an 11 nm SiNO film to prevent Sn out-diffusion upon annealing. This was only partially effective. Samples were then annealed in inert atmosphere either at 350°C varying anneal time or for 100 s varying temperature from 300 to 500°C. SPER was effective to anneal damage without Sn diffusion at 350° for samples implanted at medium and low fluences whereas the 5×10 at/cm samples remained with a ∼15 nm amorphous layer even when applying the highest thermal budget. © 2012 American Institute of Physics

Immune-Complex Mimics as a Molecular Platform for Adjuvant-Free Vaccine Delivery

Protein-based vaccine development faces the difficult challenge of finding robust yet non-toxic adjuvants suitable for humans. Here, using a molecular engineering approach, we have developed a molecular platform for generating self-adjuvanting immunogens that do not depend on exogenous adjuvants for induction of immune responses. These are based on the concept of Immune Complex Mimics (ICM), structures that are formed between an oligomeric antigen and a monoclonal antibody (mAb) to that antigen. In this way, the roles of antigens and antibodies within the structure of immune complexes are reversed, so that a single monoclonal antibody, rather than polyclonal sera or expensive mAb cocktails can be used. We tested this approach in the context of Mycobacterium tuberculosis (MTB) infection by linking the highly immunogenic and potentially protective Ag85B with the oligomeric Acr (alpha crystallin, HspX) antigen. When combined with an anti-Acr monoclonal antibody, the fusion protein formed ICM which bound to C1q component of the complement system and were readily taken up by antigen-presenting cells in vitro. ICM induced a strong Th1/Th2 mixed type antibody response, which was comparable to cholera toxin adjuvanted antigen, but only moderate levels of T cell proliferation and IFN-γ secretion. Unfortunately, the systemic administration of ICM did not confer statistically significant protection against intranasal MTB challenge, although a small BCG-boosting effect was observed. We conclude that ICM are capable of inducing strong humoral responses to incorporated antigens and may be a suitable vaccination approach for pathogens other than MTB, where antibody-based immunity may play a more protective role

Adenosine A2A receptors modulate BDNF both in normal conditions and in experimental models of Huntington’s disease

Brain-derived neurotrophic factor (BDNF), a member of the neurotrophin family, enhances synaptic transmission and regulates neuronal proliferation and survival. Functional interactions between adenosine A2A receptors (A2ARs) and BDNF have been recently reported. In this article, we report some recent findings from our group showing that A2ARs regulate both BDNF functions and levels in the brain. Whereas BDNF (10 ng/ml) increased the slope of excitatory postsynaptic field potentials (fEPSPs) in hippocampal slices from wild-type (WT) mice, it was completely ineffective in slices taken from A2AR knock-out (KO) mice. Furthermore, enzyme immunoassay studies showed a significant reduction in hippocampal BDNF levels in A2AR KO vs. WT mice. Having found an even marked reduction in the striatum of A2AR KO mice, and as both BDNF and A2ARs have been implicated in the pathogenesis of Huntington’s disease (HD), an inherited striatal neurodegenerative disease, we then evaluated whether the pharmacological blockade of A2ARs could influence striatal levels of BDNF in an experimental model of HD-like striatal degeneration (quinolinic acid-lesioned rats) and in a transgenic mice model of HD (R6/2 mice). In both QA-lesioned rats and early symptomatic R6/2 mice (8 weeks), the systemic administration of the A2AR antagonist SCH58261 significantly reduced striatal BDNF levels. These results indicate that the presence and the tonic activation of A2ARs are necessary to allow BDNF-induced potentiation of synaptic transmission and to sustain a normal BDNF tone. The possible functional consequences of reducing striatal BDNF levels in HD models need further investigation

A Kinetic Study of Acrylamide/ Acrylic Acid Copolymerization

Homo- and co-polymers of acrylamide (AAm) and acrylic acid (or acrylate salt) (AA) or methacrylic acid (MAA)) are important classes of water-soluble polymers due to their numerous applications in fields such as super absorbents, additives in cosmetics, membrane technology, waste-water treatment and oil field operations. These polymers are generally made by free radical polymerization. For copolymerization reactions it is extremely important to know the details of reaction kinetics in order to ascertain the kinetic effects of different reaction parameters, which ultimately dictate final copolymer composition, microstructure and properties. The reactivity ratios for copolymerization of AAm and AA have been shown to be dependent on pH and they also change with reaction solvent. The present experimental investigation has been performed to study the kinetics of copolymerization of these monomers in aqueous and alcoholic media by considering factors such as type of initiator and solvent, and pH, in order to determine how they affect the reactivity ratios of these monomers. Reactivity ratios were determined by non-linear least squares (NLLS) and the error-in-variables-model (EVM) techniques and full conversion range kinetic investigations were carried out to confirm these values

Temozolomide- and fotemustine-induced apoptosis in human malignant melanoma cells: response related to MGMT, MMR, DSBs, and p53

Malignant melanomas are highly resistant to chemotherapy. First-line chemotherapeutics used in melanoma therapy are the methylating agents dacarbazine (DTIC) and temozolomide (TMZ) and the chloroethylating agents BCNU and fotemustine. Here, we determined the mode of cell death in 11 melanoma cell lines upon exposure to TMZ and fotemustine. We show for the first time that TMZ induces apoptosis in melanoma cells, using therapeutic doses. For both TMZ and fotemustine apoptosis is the dominant mode of cell death. The contribution of necrosis to total cell death varied between 10 and 40%. The O6-methylguanine-DNA methyltransferase (MGMT) activity in the cell lines was between 0 and 1100 fmol mg−1 protein, and there was a correlation between MGMT activity and the level of resistance to TMZ and fotemustine. MGMT inactivation by O6-benzylguanine sensitized all melanoma cell lines expressing MGMT to TMZ and fotemustine-induced apoptosis, and MGMT transfection attenuated the apoptotic response. This supports that O6-alkylguanines are critical lesions involved in the initiation of programmed melanoma cell death. One of the cell lines (MZ7), derived from a patient subjected to DTIC therapy, exhibited a high level of resistance to TMZ without expressing MGMT. This was related to an impaired expression of MSH2 and MSH6. The cells were not cross-resistant to fotemustine. Although these data indicate that methylating drug resistance of melanoma cells can be acquired by down-regulation of mismatch repair, a correlation between MSH2 and MSH6 expression in the different lines and TMZ sensitivity was not found. Apoptosis in melanoma cells induced by TMZ and fotemustine was accompanied by double-strand break (DSB) formation (as determined by H2AX phosphorylation) and caspase-3 and -7 activation as well as PARP cleavage. For TMZ, DSBs correlated significantly with the apoptotic response, whereas for fotemustine a correlation was not found. Melanoma lines expressing p53 wild-type were more resistant to TMZ and fotemustine than p53 mutant melanoma lines, which is in marked contrast to previous data reported for glioma cells treated with TMZ. Overall, the findings are in line with the model that in melanoma cells TMZ-induced O6-methylguanine triggers the apoptotic (and necrotic) pathway through DSBs, whereas for chloroethylating agents apoptosis is triggered in a more complex manner

Pollen viability for air pollution bio-monitoring

Biological characterization of Corylus avellana L. and Pinus nigra L. pollen samples was carried out to determine the actual value of pollen as a bio-indicator of the effects of atmospheric pollution, using samples from plants naturally developed in sites controlled for air pollution. In Trentino (North Italy), we selected six stations at three different levels of air pollution, which are constantly monitored with automatic gauges by the Environmental Protection Agency of Trento. First results showed that pollen viability of both species, germinability and pollen tube length of P. nigra, were higher in areas with no road traffic compared to heavy traffic ones. Pollen viability of P. nigra was positively correlated to ozone (O3) concentrations and altitude but negatively to sulphur dioxide (SO2), particulate matter with a diameter less than 10 um (PM10), nitrogen oxides (NOx) and nitrogen dioxide (NO2) concentration