397 research outputs found
Systema philosophiae universae : publicae diiudicationi propositum ...
No full textpraeside P. Oswaldo Hespelin ... defendente ... D. Iosepho Claudio Dominico Maria Merlet de Treuheim ...anno salutis MDCCLXII. XV.. Kalend. Septemb. ...Disp., Kloster Weingarten, 176
Études littéraires sur les grands classiques latins, par M. Gustave Merlet, Paris, 1884, Hachette et Cie
No full textD. C. Études littéraires sur les grands classiques latins, par M. Gustave Merlet, Paris, 1884, Hachette et Cie. In: La revue pédagogique, tome 5, Juillet-Décembre 1884. pp. 364-365
Inventaire sommaire des archives départementales d'Eure-et-Loir, par Lucien Merlet.
No full textArbois de Jubainville Henri d'. Inventaire sommaire des archives départementales d'Eure-et-Loir, par Lucien Merlet.. In: Bibliothèque de l'école des chartes. 1866, tome 27. pp. 385-386
Les études littéraires sur les classiques français. Les classiques latins et les classiques grecs, de M. Gustave Merlet.
No full textD. C. Les études littéraires sur les classiques français. Les classiques latins et les classiques grecs, de M. Gustave Merlet.. In: Manuel général de l'instruction primaire : journal hebdomadaire des instituteurs. 52e année, tome 21, 1885. pp. 145-147
Characterisation of the structure, deuterium quadrupolar tensors, and orientational order of acenaphthene, a rigid, prochiral molecule, from the NMR spectra of samples dissolved in nematic and chiral nematic liquid crystalline solvents
No full textMolecules like acenaphthene which have a point group symmetry of C-2v behave as though their symmetry is C-2 when dissolved in chiral nematic liquid crystalline solvents. To quantify this effect a sample of perdeuterated acenaphthene dissolved in the chiral nematic solvent formed by dissolving poly-(gamma -benzyl-L-glutamate), PBLG, in CHCl3 has been studied by deuterium NMR spectroscopy. The quadrupolar splittings obtained were used to determine the orientational order parameters of acenaphthene-d(10) when dissolved in PBLG/CHCl3. To do this it was necessary to also record and analyse the proton and deuterium spectra given by a sample containing both acenaphthene and acenaphthene-d(10) in a non-chiral liquid crystalline solvent. The proton spectrum is very complex, and was analysed only after first recording and analysing the simpler H-1-{H-2} spectrum given by a sample of acenaphthene-d(6). This procedure finally yielded a set of dipolar couplings for the fully protonated molecule, which after correction for vibrational motion, were used to determine both the relative positions of the protons and the orientational order of the molecules. This information was then used to derive the quadrupolar coupling constants from the measured quadrupolar splittings. The lowering of the symmetry of the orientational distribution function is quantified by the angle alpha by which the principal axes of the molecular orientational order matrix of acenaphthene dissolved in PBLG/CHCl3 are rotated out of the plane defined by the aromatic ring. The values of alpha are in the range 1.5 +/- 0.1 degrees to 1.7 +/- 0.1 degrees for the temperature range 295-330 K
An investigation of the structure and bond rotational potential of some fluorinated ethanes by NMR spectroscopy of solutions in nematic liquid crystalline solvents
No full textNMR spectra of 1,2-dibromo-1,1-difluoroethane and 1-bromo-2-iodo-tetrafluoroethane dissolved in nematic liquid crystalline solvents have been analysed to yield the magnitudes and signs of the scalar couplings, J(ij), and total anisotropic couplings, T-ij, between all the H-1, F-19, and C-13 nuclei, except for those between two C-13 nuclei. The values obtained for Tij in principle contain a contribution from J(ij)(aniso), the component along the static applied magnetic field of the anisotropic part of the electron-mediated spin-spin coupling. Neglecting this contribution allows partially averaged dipolar couplings, D-ij, to be extracted from the T-ij, and these were used to determine the structure, orientational order, and the conformational distribution generated by rotation about the C-C bond. The values obtained are compared with the results of calculations by ab initio and density functional methods. The differences found are no greater than those obtained for similar compounds which do not contain fluorine, so that there is no definitive evidence for significant contributions from J(CF)(aniso) or J(FF)(aniso) in the two compounds studied
Selective detection of the proton NMR spectra of molecules containing rare spins at natural abundance in liquid crystalline samples
No full textIt is shown that the proton NMR spectra of molecules containing rare spins at natural abundance dissolved in a liquid crystalline solvent can be obtained free from the strong lines from the spectrum of the abundant isotopomer by the 2D HSQC NMR experiment. The technique can also give the individual chemical shifts of the rare spins, and, for a molecule containing another abundant nucleus, such as fluorine, the rare spin-F-19 total anisotropic couplings are also obtained. The usefulness of the technique is demonstrated for molecules containing C-13 as the rare spins
Liouville type results for local minimizers of the micromagnetic energy
No full textWe study local minimizers of the micromagnetic energy in small ferromagnetic 3d convex particles for which we justify the Stoner–Wohlfarth approximation: given a uniformly convex shape Ω⊂R3, there exist δc>0 and C>0 such that for 01, p≠d) is constant
Magnetic field induced dipolar couplings in the pretransitional region of a nematic liquid crystal
No full textC-13 and H-1 NMR spectroscopy have been used to study the orientational order which develops when a nematogenic compound, 4-pentyl-4' -cyanobiphenyl (5CB), approaches the transition from the isotropic to the nematic phase at T-NI. The experiments yield values of field induced dipolar couplings, D-1(CHi)B, between all of the directly bonded carbon and hydrogen nuclei in the molecule, and 2D(HH)(B), the geminal dipolar coupling between protons in the first methylene group in the alkyl chain. The temperature dependence of these couplings shows that in each case they follow a divergence behavior governed by (T - T*)(-1),where T* is a temperature determined from the experimental data and which is close to but less than TNI. Experiments performed at spectrometer field strengths of 11.75 and 18.79 T confirm the prediction that the induced couplings should depend on the square of the applied field strength. It was found that, within experimental error, T* is the same for each field-induced coupling, and that T-NI - T* is the same at 11.75 and 18.79 T. It is shown that the set of field-induced couplings 1D(CHi)(B) obtained at a temperature close to T-NI can be used to derive a conformer distribution for 5CB in the isotropic phase
Evaluation of element accumulation and oxidative stress in bees due to a landfill waste fire event
No full textLandfill fires can contribute significantly to air pollution (1). Several pollutants can be emitted during waste combustion, such as toxic or potentially toxic elements (1,2). In particular, chemicals have environmental and health impacts that can also affect bee’s health (2,3). The present study aimed to evaluate the impact of air pollution from waste fires on bee health, in terms of oxidative stress and metal accumulation, as well as the possible beneficial effect of feeding probiotics and Quassia amara to bees.
Six beehives were considered near the Malagrotta landfill, central Italy (41°51'49.9 N 12°19'46.5 E) before and after a landfill fire event on 15 June 2022. Bees were analyzed for elemental content by a quadrupole inductively coupled plasma mass spectrometry and cold vapor atomic fluorescence spectrometry (2,3), oxidative stress by hydrogen peroxide and protein carbonyl group contents (3), and metabolic profiles by 1H-NMR (3).
Compared with control bees, lower concentrations of As, B, Ba, Cd, Co, Fe, Li, Mn, Ni, Pb, Sn, Ti, and U were found in probiotic-fed bees, and Ba, Be, Cd, Co, Fe, Li, Mn, Sn, Ti, and U in Q. amara-fed bees, indicating a possible protective action of probiotics and medicinal plants against the accumulation of toxic or potentially toxic elements (2,3). The administration of probiotics and Q. amara to bees has also shown a protective effect against the oxidative stress caused by the fire of landfill waste (3). The comparison of the metabolic profiles through pre- and post-event PCA analyses showed that bees treated with different feeds react differently to the environmental event. The greatest differences in metabolic profiles were observed between the placebo-fed bees compared to the others.
This study can help to understand how some stress factors can affect the health of bees and to take measures to protect these precious insects.
Acknowledgements: The authors wish to thank Marco Papi, Marco Papi Azienda Agricola ed Apistica, Rome (Italy), for the study’s precious support and all the sampling stages. We acknowledge the Ph.D. programs on green topics, PON Research and Innovation 2014–2020 project, funded by FSE REACT-EU.
References
[1] Dabrowska D., Rykala W., Nourani V. Sustainability, 2023, 15(7), 5713. 10.3390/su15075713
[2] Astolfi M.L., Conti M.E., Messi M., Marconi E. Chemosphere, 2022, 308, 136261. 10.1016/j.chemosphere.2022.136261
[3] Giampaoli O., Messi M., Merlet T., Sciubba F., Canepari S., Spagnoli M, Astolfi M.L. Environmental Science and Pollution Research, 2023, 1-17. 10.1007/s11356-023-31561-
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