Search results for "PMA"
showing 10 items of 118 documents
Interaction of a Recombinant Prion Protein with Organo-Mineral Complexes as Assessed by FT-IR and CPMAS 13C NMR Analysis
2010
Prion proteins are considered as the main agents for the Transmissible Spongiform Encephalopathies (TSE). The misfolded form, PrP Sc , which is also indicated as the etiological agent for TSE, exhibits high resistance to degradation in environmental processes. Soil contamination by prion proteins is a real environmental issue since contaminated soils can become potential reservoir and diffuser for TSE infectivity. In this work, the interaction of prion protein with organo- mineral complexes was studied by using a recombinant non pathogenic prion protein and a model soil system. This latter was represented by a soil manganese mineral coated with polymerized catechol. FT-IR spectra showed ami…
Dynamics of cross polarization in solid state nuclear magnetic resonance experiments of amorphous and heterogeneous natural organic substances
2008
Nuclear magnetic resonance (NMR) experiments on carbon-13 in the solid state were done with cross polarization (CP) and magic angle spinning (MAS) in order to overcome the low NMR sensitivity of (13)C and the chemical shift anisotropy, respectively. In the present research, CPMAS (13)C-NMR spectra were collected by modulating the contact time needed for cross polarization (variable contact times experiments, VCT) on two different humic acids (a soil-HA and a coal-HA). VCT data were fitted by a model containing either a monotonic or a non-monotonic cross polarization term. The non-monotonic model, which fitted the experimental results better than the monotonic one, provided two cross-polariz…
Effect of Heating Time and Temperature on the Chemical Characteristics of Biochar from Poultry Manure
2014
Poultry manure (PM) chars were obtained at different temperatures and charring times. Chemical-physical characterization of the different PM chars was conducted by cross-polarization magic angle spinning (CPMAS) (13)C NMR spectroscopy and thermal analysis. CPMAS (13)C NMR spectra showed that the chemical composition of PM char is dependent on production temperature rather than on production duration. Aromatic and alkyl domains in the PM chars obtained at the lowest temperatures remained unchanged at all heating times applied for their production. The PM char obtained at the highest temperature consisted only of aromatic structures having chemical nature that also appeared invariant with hea…
Interactions between 2-Aminobenzothiazole and Natural Organic Matter as Evidenced by CPMAS Nitrogen-15 NMR Spectroscopy
2009
Cross-polarization magic angle spinning (CPMAS) 15N nuclear magnetic resonance (NMR) spectroscopy was used to study the interactions between 2-aminobenzothiazole (ABT) and natural organic matter in the presence of the natural enzyme laccase and synthetic air. Through the use of synthesized model compounds, we were able to confirm previous findings by CPMAS 13C NMR spectroscopy that showed the formation of covalent amide bonds. We also provide evidence of the presence of two additional H bonds between ABT and the natural organic matter. Both H bonds involved the amino and thiazole groups of ABT.
Synthesis, Characterization and Preliminary Biological Evaluation of P(HPMA)-b-P(LLA) Copolymers: A New Type of Functional Biocompatible Block Copoly…
2010
We describe a synthetic pathway to functional P(HPMA)-b-P(LLA) block copolymers. The synthesis relies on a combination of ring-opening polymerization of L-lactide, conversion into a chain transfer agent (CTA) for the RAFT polymerization of pentafluorophenyl methacrylate. A series of block copolymers was prepared that exhibited molecular weights $\overline M _{\rm n}$ ranging from 7 600 to 34 300 g · mol(-1) , with moderate PDI between 1.3 and 1.45. These reactive precursor polymers have been transformed into biocompatible P(HPMA)-b-P(LLA) copolymers and their fluorescently labeled derivatives by facile replacement of the pentafluorophenyl groups. The fluorescence label attached to this new …
Effect of ramp size and sample spinning speed on CPMAS 13C NMR spectra of soil organic matter
2011
Abstract Cross polarization (CP) magic angle spinning (MAS) 13C NMR spectroscopy is a solid state NMR technique widely applied to study the chemical composition of natural organic matter. In high magnetic fields (>7 T), fast sample spinning is required in order to reduce the influence of spinning sidebands underlying other chemical shift regions. As the spinning speed increases, the Hartmann–Hahn matching profiles break down into a series of narrow matching bands. In order to account for this instability variable amplitude cross polarization techniques (e.g. VACP, ramp-CP) have been developed. In the present study, we experimentally verified the stability of the Hartmann–Hahn condition unde…
Alma Mater
2016
In human cumulus cells, the apoptotic rate may be considered an indicator for the selection of embryos to improve ongoing pregnancy and implantation …
2014
In order to identify the embryos with higher implantation potential to increase the clinical outcomes after ICSI, the apoptotic rate in human cumulus cells for the embryo selection on day 3, as an adjunct to morphology evaluation, could be considered a new tool compared with embryo selection by morphology alone. Several studies have demonstrated a lower cumulus cell apoptotic rate in women who achieved pregnancy compared with women who did not become pregnant after ICSI. A prospective randomized observational study on 76 ICSI patients was performed before Ovum Pick-Up. Patients were randomized into either the control group (embryo selection by morphology only, A group: 48 patients) or the t…
Spektra menedžeris datu iegūšanai uz Android OS, lietojot dronu
2017
Super augsto frekvenču viļņu spektra analīzi no gaisa var veikt ar helikopteru, bet tā ir dārga metode un šo darbu varētu nomainīt droni. Darba mērķis bija izpētīt, vai saziņa starp spektra analizatoru, izmantojot drona saziņas kanālu, un mobilo ierīci, spēj notikt pietiekoši efektīvi un stabili, lai saņemtie un apstrādātie datu būtu noderīgi reālam darbam. Uzdevums bija radīt programmatūru mobilajai ierīcei, kas spētu izmantot drona programmatūras izstrādnes un izmantojot tās sazināties ar spektra analizatoru, kā arī spētu saņemt, apstrādāt un attēlot reālā laika datus uz ekrāna, kā arī ļaut uz ekrāna veikt citas lietotājam nepieciešamās darbības spektra analīzei. Izpildot uzdevumus un izp…
Bērnu pornogrāfiskā materiāla novēršana datu apmaiņas sistēmās
2021
Bakalaura darba tēma ir “Bērnu pornogrāfiskā materiāla novēršana datu apmaiņas sistēmās”. Darbā tiek pētīta bērnu pornogrāfijas attīstības vēsture, tā aprite datu apmaiņas sistēmās, materiāla ietekme uz upuriem un tiesībaizsardzības iestāžu darbiniekiem, kā arī nacionālā mēroga pieredze šī materiāla aprites novēršanā. Tiek noskaidroti ietekmējošie faktori bērnu pornogrāfiskā materiāla apritei datu apmaiņas sistēmās un noteikta saikne starp bērnu pornogrāfijas skatīšanos ar fiziskiem seksuāliem noziegumiem. Darba ietvaros tiek sniegta izpratne par kriminalizēšanas nozīmi materiāla aprites ierobežošanā, tiek analizēta psiholoģiskās palīdzības sniegšanas un sabiedrības iesaistīšanas nozīme noz…