SHORT CHARACTERIZATION OF PLANT SPECIES FROM CENTAUREA GENUS PRESENT IN ”AL. BELDIE” HERBARIUM FROM ”MARIN DRĂCEA” NATIONAL INSTITUTE FOR RESEARCH AND DEVELOPMENT IN FORESTRY - BUCHAREST

”Al Beldie” herbarium from ”Marin Drăcea” National Institute for Research and Development in Forestry is an important herbarium with a significant role in the present research paper.This herbarium is ilisted in Index Herbaria and is composed of approximately 60.000 sheets with dried specimens of plants. From those 60.000 sheets, 71 belong to the genus Centaurea, with 19 species to be more precise. All of these species were collected by known personalities in the field of systematic botany, most of them being Romanian. The species were collected between 1855 and 1951 from the entire world, with a great majority from Romania. The aim of this article is to describe some species of Centaurea that are present in this herbarium. In this way it can be observed how important it is to collect, identify and preserve sheets with dried species in herbarium, given that these species of plants can be very hard to identify

Chemiresistive Sensor Arrays from Conductive 2D Metal–Organic Frameworks

Applications of porous metal–organic frameworks (MOFs) in electronic devices are rare, owing in large part to a lack of MOFs that display electrical conductivity. Here, we describe the use of conductive two-dimensional (2D) MOFs as a new class of materials for chemiresistive sensing of volatile organic compounds (VOCs). We demonstrate that a family of structurally analogous 2D MOFs can be used to construct a cross-reactive sensor array that allows for clear discrimination between different categories of VOCs. Experimental data show that multiple sensing mechanisms are operative with high degrees of orthogonality, establishing that the 2D MOFs used here are mechanistically unique and offer advantages relative to other known chemiresistor materials.Camille & Henry Dreyfus Foundation. Postdoctoral Program in Environmental ChemistrAlfred P. Sloan FoundationResearch Corporation for Science Advancement3M CompanyNational Science Foundation (U.S.). Graduate Research Fellowship Program (Grant 1122374)Massachusetts Institute of Technology. Institute for Soldier Nanotechnologie

Observing Nearby Nuclei on Paramagnetic Trityls and MOFs via DNP and Electron Decoupling

Dynamic nuclear polarization (DNP) is an NMR sensitivity enhancement technique that mediates polarization transfer from unpaired electrons to NMR-active nuclei. Despite its success in elucidating important structural information on biological and inorganic materials, the detailed polarization-transfer pathway from the electrons to the nearby and then the bulk solvent nuclei, and finally to the molecules of interest-remains unclear. In particular, the nuclei in the paramagnetic polarizing agent play significant roles in relaying the enhanced NMR polarizations to more remote nuclei. Despite their importance, the direct NMR observation of these nuclei is challenging because of poor sensitivity. Here, we show that a combined DNP and electron decoupling approach can facilitate direct NMR detection of these nuclei. We achieved an ∼80 % improvement in NMR intensity via electron decoupling at 0.35 T and 80 K on trityl radicals. Moreover, we recorded a DNP enhancement factor of urn:x-wiley:09476539:media:chem202202556:chem202202556-math-0001 ∼90 and ∼11 % higher NMR intensity using electron decoupling on paramagnetic metal-organic framework, magnesium hexaoxytriphenylene (MgHOTP MOF)

Serum selenium concentrations in patients with newly diagnosed lymphoid malignancies

Background. Increased mortality from lymphoid malignancies following exposure to environmental selenium has recently been reported, Moreover, conflicting results have been found in investigations examining the relationship between serum concentrations of selenium and some clinical features of malignant lymphoproliferative diseases. Methods, Serum concentrations of selenium were analyzed by atomic absorption spectrometry in fifty-nine patients with newly diagnosed chronic lymphoid malignancies and in forty control subjects. Results. Selenium concentrations were significantly lower in patients than in control subjects, However, when only patients with localized disease were compared to controls, no significant difference in serum selenium concentrations was observed. Clinical stage was inversely associated with selenium levels. High-grade non-Hodgkin's lymphoma was characterized by lower selenium levels than low-grade and intermediate-grade disease. Selenium levels were positively associated with albumin and hemoglobin, and inversely correlated with serum concentrations of beta 2-microglobulin and with erythrocyte sedimentation rate. Conclusions. The findings of this study do not suggest that a high selenium intake represents a risk factor for malignant lymphoproliferative diseases, but limitations of the investigation hamper evaluation of the results. The possible utility of determining serum concentrations of selenium in the clinical evaluation ofpatients with lymphoid malignancies merits examination in larger studies

Spectroscopy of the odd-odd fp-shell nucleus 52Sc from secondary fragmentation

The odd-odd fp-shell nucleus 52Sc was investigated using in-beam gamma-ray spectroscopy following secondary fragmentation of a 55V and 57Cr cocktail beam. Aside from the known gamma-ray transition at 674(5)keV, a new decay at E_gamma=212(3) keV was observed. It is attributed to the depopulation of a low-lying excited level. This new state is discussed in the framework of shell-model calculations with the GXPF1, GXPF1A, and KB3G effective interactions. These calculations are found to be fairly robust for the low-lying level scheme of 52Sc irrespective of the choice of the effective interaction. In addition, the frequency of spin values predicted by the shell model is successfully modeled by a spin distribution formulated in a statistical approach with an empirical, energy-independent spin-cutoff parameter.Comment: accepted for publication in PR

Measurement of excited states in 40Si and evidence for weakening of the N=28 shell gap

Excited states in 40Si have been established by detecting gamma-rays coincident with inelastic scattering and nucleon removal reactions on a liquid hydrogen target. The low excitation energy, 986(5) keV, of the 2+[1] state provides evidence of a weakening in the N=28 shell closure in a neutron-rich nucleus devoid of deformation-driving proton collectivity.Comment: accepted for publication in PR

Large scale shell model calculations for odd-odd 58−62^{58-62}Mn isotopes

Large scale shell model calculations have been carried out for odd-odd $^{58-62}$Mn isotopes in two different model spaces. First set of calculations have been carried out in full $\it{fp}$ shell valence space with two recently derived $\it{fp}$ shell interactions namely GXPF1A and KB3G treating $^{40}$Ca as core. The second set of calculations have been performed in ${fpg_{9/2}}$ valence space with the $fpg$ interaction treating $^{48}$Ca as core and imposing a truncation by allowing up to a total of six particle excitations from the 0f$_{7/2}$ orbital to the upper $\it{fp}$ orbitals for protons and from the upper $\it{fp}$ orbitals to the 0g$_{9/2}$ orbital for neutron. For low-lying states in $^{58}$Mn, the KB3G and GXPF1A both predicts good results and for $^{60}$Mn, KB3G is much better than GXPF1A. For negative parity and high-spin positive parity states in both isotopes $fpg$ interaction is required. Experimental data on $^{62}$Mn is sparse and therefore it is not possible to make any definite conclusions. More experimental data on negative parity states is needed to ascertain the importance of 0g$_{9/2}$ and higher orbitals in neutron rich Mn isotopes.Comment: 5 pages, 4 figures, Submitted to Eur. Phys. J.

Enhanced collectivity in 74Ni

The neutron-rich nucleus 74Ni was studied with inverse-kinematics inelastic proton scattering using a 74Ni radioactive beam incident on a liquid hydrogen targetat a center-of-mass energy of 80 MeV. From the measured de-excitation gamma-rays, the population of the first 2+ state was quantified. The angle-integrated excitation cross section was determined to be 14(4) mb. A deformation length of delta = 1.04(16) fm was extracted in comparison with distorted wave theory, which suggests that the enhancement of collectivity established for 70Ni continues up to 74Ni. A comparison with results of shell model and quasi-particle random phase approximation calculations indicates that the magic character of Z = 28 or N = 50 is weakened in 74Ni