Articles de revues : « N-dimer (ND) or C-dimer (CD) »

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Kolb, Torsten, Atta M. Arif et Richard D. Ernst. « Synthesis and Structural Study of the (N,N,N′,N′-Tetraethylethylenediamine)CdFe(CO)4 Dimer ». Journal of Crystallography 2014 (7 avril 2014) : 1–5. http://dx.doi.org/10.1155/2014/168320.

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The new [(teeda)CdFe(CO)4]2 complex has been isolated from the reaction of [(NH3)2CdFe(CO)4]n with tetraethylethylenediamine. Unlike previous structural reports of ligand adducts of [L2CdFe(CO)4]x complexes, which have all been trimeric species composed of six-membered Cd3Fe3 rings, the teeda complex crystallized as a dimer, analogous to [(2,2-bpy)ZnFe(CO)4]2. As in the zinc dimer, significant distortion arises from steric interactions between the axial carbonyl ligands on opposing iron centers. The complex sits on an inversion center, leading to two independent Cd–Fe distances, 2.7244(6) and 2.7433(6) Å, and crystallizes in the monoclinic space group P21/a with a = 14.8546(2) Å, b = 15.1647(3) Å, c = 15.5252(3) Å, β = 90.9517(12)°, and Dcalc = 1.719 g/cm3 at 150(1) K.

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Onwudiwe, Damian C., Madalina Hrubaru, Eric C. Hosten et Charmaine Arderne. « Bis(μ-N,N-diallyldithiocarbamato)bis[(N,N-diallyldithiocarbamato)cadmium] ». Acta Crystallographica Section E Crystallographic Communications 73, n^o 9 (21 août 2017) : 1353–56. http://dx.doi.org/10.1107/s2056989017011616.

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The title compound, [Cd2(C7H10NS2)4], is a neutral dinuclear cadmium(II) complex bearing four bisN,N-diallyldithiocarbamate ligands coordinating to two CdIIcations. In each of the monomeric subunits, there are four S atoms of two dithiocarbamate ligands [Cd—S = 2.5558 (3), 2.8016 (3), 2.6050 (3) and 2.5709 (3) Å] that coordinate to one CdIIatom in a bidentate mode. The dimers are located over an inversion centre bridged by two additional bridging Cd—S bonds [2.6021 (3) Å], leading to a substantial distortion of the geometry of the monomeric subunit from the expected square-planar geometry. The five-coordinate environment around each of the CdIIions in the dimer is best described as substantially tetragonally distorted square pyramidal. The dithiocarbamate groups are themselves planar and are also coplanar with the CdIIions. The negative charge on these groups is delocalized by resonance across the S atoms bound to the CdIIcation. This delocalization of the π electrons in the dithiocarbamate groups also extends to the C—N bonds as they reveal significant double bond character [C—N = 1.3213 (16) and 1.3333 (15) Å].

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STEER, Brian A., Ariel A. DINARDO et A. Rod MERRILL. « Colicin E1 forms a dimer after urea-induced unfolding ». Biochemical Journal 340, n^o 3 (8 juin 1999) : 631–38. http://dx.doi.org/10.1042/bj3400631.

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Unfolding of the soluble colicin E1 channel peptide was examined with the use of urea as a denaturant; it was shown that it unfolds to an intermediate state in 8.5 M urea, equivalent to a dimeric species previously observed in 4 M guanidinium chloride. Single tryptophan residues, substituted into the peptide at various positions by site-directed mutagenesis, were employed as fluorescent probes of local unfolding. Unfolding profiles for specific sites within the peptide were obtained by quantifying the shifts in the fluorescence emission maxima of single tryptophan residues on unfolding and plotting them against urea concentration. Unfolding reported by tryptophan residues in the C-terminal region was not characteristic of complete peptide denaturation, as evidenced by the relatively blue-shifted values of the fluorescence emission maxima. Unfolding was also monitored by using CD spectroscopy and the fluorescent probe 2-(p-toluidinyl)-naphthalene 6-sulphonic acid; the results indicated that unfolding of helices is concomitant with the exposure of protein non-polar surface. Unfolding profiles were evaluated by non-linear least-squares curve fitting and calculation of the unfolding transition midpoint. The unfolding profiles of residues located in the N-terminal region of the peptide had lower transition midpoints than residues in the C-terminal portion. The results of unfolding analysis demonstrated that urea unfolds the peptide only partly to an intermediate state, because the C-terminal portion of the channel peptide retained significant structure in 8.5 M urea. Characterization of the peptide's global unfolding by size-exclusion HPLC revealed that the partly denatured structure that persists in 8.5 M urea is a dimer of two channel peptides, tightly associated by hydrophobic interactions. The presence of the dimerized species was confirmed by SDS/PAGE and intermolecular fluorescence resonance energy transfer.

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Lee, Hwei-Jen, Young-Hsang Lai, Su-Ying Wu et Yu-Hou Chen. « The effect of N-terminal truncation on double-dimer assembly of goose δ-crystallin ». Biochemical Journal 392, n^o 3 (6 décembre 2005) : 545–54. http://dx.doi.org/10.1042/bj20050860.

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δ-Crystallin is a soluble structural protein in avian eye lenses that confers special refractive properties. In the presence of GdmCl (guanidinium chloride), tetrameric δ-crystallin undergoes dissociation via a dimeric state to a monomeric molten globule intermediate state. The latter are denatured at higher GdmCl concentrations in a multi-state manner. In the present study, the X-ray structure of goose δ-crystallin was determined to 2.8 Å (1 Å=0.1 nm). In this structure the first 25 N-terminal residues interact with a hydrophobic cavity in a neighbouring molecule, stabilizing the quaternary structure of this protein. When these 25 residues were deleted this did not produce any gross structural changes, as judged by CD analysis, but slightly altered tryptophan fluorescence and ANS (8-anilino-1-naphthalenesulphonic acid) spectra. The dimeric form was significantly identified as judged by sedimentation velocity and nondenaturing gradient gel electrophoresis. This mutant had increased sensitivity to temperature denaturation and GdmCl concentrations of 0.3–1.0 M. This protein was destabilized about 3.3 kcal/mol (1 kcal=4.184 kJ) due to N-terminal truncation. After incubation at 37 °C N-terminal truncated proteins were prone to aggregation, suggesting the presence of the unstable dimeric conformation. An important role for the N-terminus in dimer assembly of goose δ-crystallin is proposed.

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Berg, David J., et Roland AL Gendron. « Synthesis, solid state structure, and solution behaviour of the lighter lanthanide bis(trimethylsilyl)amido chlorides, [Ln{N(SiMe3)2}2(THF)(µ-Cl)]2 (Ln = Ce, Nd) ». Canadian Journal of Chemistry 78, n^o 4 (1 avril 2000) : 454–58. http://dx.doi.org/10.1139/v00-036.

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The synthesis of [Ln{N(SiMe3)2}2(THF)(µ-Cl)]2 (Ln = Ce, 1; Nd, 2) by reaction of sodium bis(trimethylsilyl)amide (2 equiv.) with LnCl3 is reported. The same complexes were also isolated from the ligand redistribution reactions of Ln[N(SiMe3)2]3 and LnCl3 (2:1 ratio) in THF at 80°C. The crystal structure of 2, determined by X-ray diffraction, revealed a centrosymmetric dimer with bridging chlorides and pentacoordinate metal centres. 1H NMR studies show that the solid state structure is not maintained in solution. NMR evidence for the presence of Ln[N(SiMe3)2]3 and two other bis(trimethylsilyl)amide containing species, presumably Ln[N(SiMe3)2]Cl2(THF)x and Ln[N(SiMe3)2]2Cl(THF)y, is presented.Key words: lanthanide, amide, neodymium, cerium, crystal structure, X-ray, nuclear magnetic resonance, redistribution.

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Osman, Sahar, Ehab Elmadenah, Osman Elmahi, Mubarak Alkarsani, Lienda Eltayeb et Hisham Waggiallah. « Cytomorphometric Analysis of Cervical Papanicolaou Smear for Females with Gynecological Clinical Complaints ». International Journal of Biomedicine 11, n^o 1 (5 mars 2021) : 46–49. http://dx.doi.org/10.21103/article11(1)_oa9.

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Background: Limited information is provided on the quantitative cytomorphometric study of the cervical Pap test. The cervical Pap test is an important screening program for cervical cancer. A quantitative cytomorphometric examination of cervical Pap is used to accurately identify precancerous and cancerous lesions early and to reduce the occurrence and avoidance of invasive cancer. This study was aimed to assess the cytomorphological parameters (nuclear diameter [ND], cytoplasm diameter [CD], and nuclear-to-cytoplasmic ratio [N/C ratio]) of squamous epithelial cells from a cervical Pap smear. Methods and Results: A prospective study was performed on 142 consecutive cervical Pap smears from women with gynecological clinical complaints. The ND and CD were determined by the Optika optical microscope camera using a digitizer cursor in both axes. The final images were taken with an X40 magnification. The ND, CD, and the N/C ratio were then measured and expressed in micrometers. The women were classified into 5 age groups: 5(3.5%) in the age group of <19 years, 46(32%) in the 20-29 group, 67(47.2%) in the 30-39 group, 23(16.2%) in the 40-49 group, and 1(0.7%) woman was over age 50. There were no significant differences in the N/C ratio of superficial cells between age groups. The ND, CD, and the N/C ratio were significantly higher in women with clinical complaints than in women without clinical complaints Conclusion: Cytomorphometic analysis might assist in the identification of cellular alterations due to gynecological diseases and increase the sensitivity and accuracy of the Pap smear technique.

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Khan, Saeed I., Carolyn B. Knobler et Emily F. Maverick. « Benz[cd]indol-2(1H)-one at 298 and 100 K ». Acta Crystallographica Section C Crystal Structure Communications 68, n^o 1 (6 décembre 2011) : o1—o6. http://dx.doi.org/10.1107/s0108270111050281.

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Weakly diffracting crystals of benz[cd]indol-2(1H)-one (naphtholactam), C11H7NO, were unsuitable for data collection by early photographic methods. However, a diffractometer data set collected at room temperature in 1989 was solved and refined. The peak scans were broad, and the results indicated disorder or a satellite crystal. Recent data collection (on another crystal from the same sample) with an area detector at 100 K revealed the same disorder, and made it possible to refine two different, more complete, disorder models. Both models assume an occasional 180° rotation of the nearly planar centrosymmetriccis-lactam dimer. The refinements differ, especially in the anisotropic displacement parameters for the –C(=O)—NH– portion of the molecule. Both models at 100 K give a C—N (`amide') bond distance of 1.38 Å, about 0.04 Å longer than the average distance in saturated γ-lactams in the Cambridge Structural Database. Cohesive packing interactions between molecules include opposing-dipole dimers; the packing may explain the 10:1 ratio favoring the major-occupancy molecule.

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Kumar, Dinesh, et Amit Kumar. « Physicochemical, Spectral, and Biological Studies of Mn(II), Cu(II), Cd(II), Zr(OH)2(IV), and UO2(VI) Compounds with Ligand Containing Thiazolidin-4-one Moiety ». Journal of Chemistry 2014 (2014) : 1–9. http://dx.doi.org/10.1155/2014/286136.

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The Schiff base (I) upon reacting with mercaptoacetic acid in dry benzene undergoes cyclization and forms N-(2-carbamoylthienyl)-C-(3′-carboxy-2′-hydroxyphenyl)thiazolidin-4-one, LH3(II). A MeOH solution ofIIreacts with Mn(II), Cu(II), Cd(II), Zr(OH)2(IV), and UO2(VI) ions and forms the coordination compounds, [Mn(LH)(MeOH)2], [Cu(LH)]2, [Cd(LH)], [Zr(OH)2(OAc)2(LH3)], and [UO2(NO3)(LH2)(MeOH)]. The compounds have been characterized on the basis of elemental analyses, molar conductance, molecular weight, spectral (IR, reflectance, and EPR) studies and magnetic susceptibility measurements. LH3behaves as a neutral tridentate ONS donor ligand in [Zr(OH)2(OAc)2(LH3)], monobasic tridentate ONS donor ligand in [UO2(NO3)(LH2)(MeOH)], dibasic tridentate OOS donor ligand in [Cu(LH)]2and dibasic tetradentate OONO donor ligand in [Mn(LH)(MeOH)2] and [Cd(LH)]. [Cu(LH)]2is dimer, while all other compounds are monomers in diphenyl. A square-planar structure for [Cu(LH)]2, a tetrahedral structure for [Cd(LH)], an octahedral structure for [Mn(LH)(MeOH)2], a pentagonal-bipyramidal structure for [Zr(OH)2(OAc)2(LH3)], and an eight-coordinate structure for [UO2(NO3)(LH2)(MeOH)] are proposed. The ligand (II) and its compounds show antibacterial activities towardsE. coli. (Gram negative) andS. aureus(Gram positive).

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Semenova, Lioubov I., Peter C. Junk, Brian W. Skelton et Allan H. White. « Structural Systematics of Rare Earth Complexes. XVI (‘Maximally’) Hydrated Rare Earth(III) Bromides ». Australian Journal of Chemistry 52, n^o 6 (1999) : 531. http://dx.doi.org/10.1071/ch98047.

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Room-temperature single-crystal X-ray structure determinations carried out on rare earth bromides crystallized from water at room temperature define three series of hydrates LnBr3.nH2O. For Ln = La, Ce, a heptahydrate phase (n = 7) is defined, triclinic P 1, a ≈ 8·6, b ≈ 9·4, c ≈ 8·3 Å, α ≈ 108, β ≈ 99, γ ≈ 72°, isomorphous with the array described for the ‘early’ (Ln = La-Pr) rare earth chlorides, being binuclear [(H2O)7Ln(-Br)2Ln(OH2)7] Br4, Z = 1 dimer; conventional R on |F| were 0·051, 0·042 for 2323, 3451 independent ‘observed’ (I > 3σ(I)) diffractometer reflections respectively. For Ln = Pr(-)Dy, a hexahydrate phase is defined, monoclinic P 2/n, a ≈ 10·0, b ≈ 6·8, c ≈ 8·2 Å, β ≈ 93·5°, Z = 2 f.u., isomorphous with the array defined for the heavier (Ln = Nd, Lu, Y) rare earth chlorides, being [(H2O)6LnBr2] Br, with R 0·029, 0·034 for No 1590, 1388 respectively. For Ln = Ho(-)Lu, Y, an octahydrate is defined for the first time, monoclinic P 21/n, a ≈ 8·1, b ≈ 16·0, c ≈ 10·1 Å, b ≈ 94·0°, Z = 4 f.u., a new array of the form [Ln(OH2)8] Br3 emerging, with R 0·061, 0·048, 0·042 for No 1191, 2402, 1674 respectively, the metal environment being square antiprismatic.

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Ghosh, Tapanendu, Swapnadeep Mondal, Sukanya Mondal et Bholanath Mandal. « Hückel Molecular Orbital Quantities of {X,Y}-Cyclacene Graphs Under Next-Nearest-Neighbour Approximations in Analytical Forms ». Zeitschrift für Naturforschung A 74, n^o 6 (26 juin 2019) : 469–88. http://dx.doi.org/10.1515/zna-2018-0488.

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AbstractHückel molecular orbital (HMO) quantities, viz., electron densities, charge densities, bond orders, free valences, total π-electron energies and highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO–LUMO) or band gaps of {X,Y}-cyclacene graphs under next-nearest-neighbour (nnn) approximations are expressed in analytical forms within a certain range of nnn approximation parameter (m). The critical values of m for {X,Y}-cyclacenes with varying X (=C, N, B) and Y (=C, N, B) are calculated. For {X,X}-cyclacenes with a π-electron on each atom, all HMO quantities except total π-electron energies for a given value of m are found to be independent of X. The cyclic dimer (CD) is constructed in obtaining the eigenvalues corresponding to the singular points of the density of states (DOS) of such {X,Y}-cyclacene. Although the HOMO–LUMO gap of the CD differs from that of the cyclacene with a large number of repeating units (i.e. n ⟶ ∞) but becomes the same for m = 0. The analytical expressions can be used for facile computer programming in obtaining the HMO quantities. Such nnn interaction approximations actually release, to some extent, the strain that results in due to the geometrical structures of such cyclacenes, which is evident from the plots of strain energy per segment vs. contribution of such interactions on the total π-electron energy, where the slopes decrease with an increase in m. The vertical absorption energy difference for singlet-triplet states bears excellent linear correlation with the HOMO–LUMO gaps for a certain m value (m = 0.3) in the case of an even n, but for an odd n, such energy difference remains invariant.

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OBERER, Monika, Klaus ZANGGER, Stefan PRYTULLA et Walter KELLER. « The anti-toxin ParD of plasmid RK2 consists of two structurally distinct moieties and belongs to the ribbon-helix-helix family of DNA-binding proteins ». Biochemical Journal 361, n^o 1 (17 décembre 2001) : 41–47. http://dx.doi.org/10.1042/bj3610041.

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NMR and CD spectroscopy have been used to characterize, both structurally and dynamically, the 82-amino-acid ParD protein of the post-segregational killing module of the broad-host-range plasmid RP4/RK2. ParD occurs as a dimer in solution and exercises two different control functions; an autoregulatory function by binding to its own promoter PparDE and a plasmid-stabilizing function by inhibiting ParE toxicity in cells that express ParD and ParE. Analysis of the secondary structure based on the chemical-shift indices, sequential nuclear Overhauser enhancements (NOEs) and 3JHα-NH scalar coupling constants showed that the N-terminal domain of ParD consists of a short β-ribbon followed by three α-helices, demonstrating that ParD contains a ribbon-helix-helix fold, a DNA-binding motif found in a family of small prokaryotic repressors. 15N longitudinal (T1) and transverse (T2) relaxation measurements and hetero nuclear NOEs showed that ParD is divided into two separate domains, a well-ordered N-terminal domain and a very flexible C-terminal domain. An increase in secondary structure was observed upon addition of trifluoroethanol, suggested to result from the formation of structured stretches in the C-terminal part of the protein. This is the first experimental evidence that the DNA-binding domain of ParD belongs to the ribbon-helix-helix fold family, and this structural motif is proposed to be present in functionally similar antidote proteins.

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MITRA, Joydeep, Xue-jun TANG, Steven C. ALMO et Dennis SHIELDS. « Temperature-induced conformational changes in prosomatostatin-II : implications for processing ». Biochemical Journal 334, n^o 1 (15 août 1998) : 275–82. http://dx.doi.org/10.1042/bj3340275.

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Somatostatin (SRIF) is a 14-residue peptide hormone synthesized in the hypothalamus and pancreatic islets. SRIF-14 and an N-terminally extended form, SRIF-28, are generated by the proteolytic processing of an approx. 102-residue precursor prosomatostatin (proSRIF) at a single set of paired basic residues (Arg-Lys) and at a monobasic (Arg) site respectively. Previous work in our laboratory demonstrated that the propeptide of SRIF mediates intracellular sorting; we suggested that this information resides in the prohormone structure. To identify putative sorting domains we have investigated structural features of recombinant anglerfish proSRIF-II purified from Escherichia coli. Two species of proSRIF-II were obtained: a monomeric form and a disulphide-linked dimer. CD analyses revealed that monomeric proSRIF-II lacks appreciable periodic secondary structure; however, on slow heating (2 °C/min) and cooling, it assumed a predominantly α-helical conformation. When subjected to a second heating-and-cooling cycle, the α-helical conformation was maintained. In contrast, the dimeric form of proSRIF-II was predominantly α-helical and its helicity did not increase in response to heating and recooling. Our results suggest that proSRIF-II might exist in several different folding intermediate states.

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Weiner, Brian E., Hao Huang, Brian M. Dattilo, Mark J. Nilges, Ellen Fanning et Walter J. Chazin. « An Iron-Sulfur Cluster in the C-terminal Domain of the p58 Subunit of Human DNA Primase ». Journal of Biological Chemistry 282, n^o 46 (24 septembre 2007) : 33444–51. http://dx.doi.org/10.1074/jbc.m705826200.

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DNA primase synthesizes short RNA primers that are required to initiate DNA synthesis on the parental template strands during DNA replication. Eukaryotic primase contains two subunits, p48 and p58, and is normally tightly associated with DNA polymerase α. Despite the fundamental importance of primase in DNA replication, structural data on eukaryotic DNA primase are lacking. The p48/p58 dimer was subjected to limited proteolysis, which produced two stable structural domains: one containing the bulk of p48 and the other corresponding to the C-terminal fragment of p58. These domains were identified by mass spectrometry and N-terminal sequencing. The C-terminal p58 domain (p58C) was expressed, purified, and characterized. CD and NMR spectroscopy experiments demonstrated that p58C forms a well folded structure. The protein has a distinctive brownish color, and evidence from inductively coupled plasma mass spectrometry, UV-visible spectrophotometry, and EPR spectroscopy revealed characteristics consistent with the presence of a [4Fe-4S] high potential iron protein cluster. Four putative cysteine ligands were identified using a multiple sequence alignment, and substitution of just one was sufficient to cause loss of the iron-sulfur cluster and a reduction in primase enzymatic activity relative to the wild-type protein. The discovery of an iron-sulfur cluster in DNA primase that contributes to enzymatic activity provides the first suggestion that the DNA replication machinery may have redox-sensitive activities. Our results offer new horizons in which to investigate the function of high potential [4Fe-4S] clusters in DNA-processing machinery.

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Sakamoto, Keiko, Yoshihiro Agari, Kazuko Agari, Seiki Kuramitsu et Akeo Shinkai. « Structural and functional characterization of the transcriptional repressor CsoR from Thermus thermophilus HB8 ». Microbiology 156, n^o 7 (1 juillet 2010) : 1993–2005. http://dx.doi.org/10.1099/mic.0.037382-0.

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The TTHA1719 gene from Thermus thermophilus HB8 encodes an orthologue of the copper-sensing transcriptional repressor CsoR. X-ray crystal structure analysis of T. thermophilus CsoR indicated that it forms a homotetramer. The structures of the CsoR monomer and dimer are similar to those of Mycobacterium tuberculosis CsoR. In the absence of copper ions, T. thermophilus CsoR bound to the promoter region of the copper-sensitive operon copZ-csoR-copA, which encodes the copper chaperone CopZ, CsoR and the copper efflux P-type ATPase CopA, to repress their expression, while in the presence of approximately an equal amount of copper ion, CsoR was released from the DNA, to allow expression of the downstream genes. Both Cu(II) and Cu(I) ions could bind CsoR, and were effective for transcriptional derepression. Additionally, CsoR could also sense various other metal ions, such as Zn(II), Ag(I), Cd(II) and Ni(II), which led to transcriptional derepression. The copper-binding motif of T. thermophilus CsoR contains C-H-H, while those of most orthologues contain C-H-C. The X-ray crystal structure of T. thermophilus CsoR suggests that a histidine residue in the N-terminal domain is also involved in metal-ion binding; that is, the binding motif could be H-C-H-H, like that of Escherichia coli RcnR, which binds Ni(II)/Co(II). The non-conserved H70 residue in the metal-binding motif of T. thermophilus CsoR is important for its DNA-binding affinity and metal-ion responsiveness.

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Thummatudtho, Sudarat, Natthakorn Phadungsak, Kittipong Chainok, Mathi Kandiah, Alvin Lim Teik Zheng, Yoshito Andou et Supakorn Boonyuen. « Cadmium(II) and copper(II) complexes containing benzoate derivatives and 2-aminopyrimidine ligands : Synthesis, crystal structures and antibacterial activity ». Journal of Physics : Conference Series 2175, n^o 1 (1 janvier 2022) : 012024. http://dx.doi.org/10.1088/1742-6596/2175/1/012024.

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Abstract The new Cd(II) and Cu(II) complexes namely [Cd2(2-OHbza)4(apm)4] (1), [Cu2(2-OHbza)4(apm)]n•2(2-OHbza) (2) and [Cu2(2-CH3bza)4(apm)]n (3) (2-OHbza = 2-hydroxybenzoate, 2-CH3bza = 2-methylbenzoate and apm = 2-aminopyrimidine) were successfully prepared by using direct one pot synthesis method. All complexes were characterized by using CHN elemental analysis, FT-IR spectroscopy, powder X-ray diffraction and single crystal X-ray diffraction techniques. Compound 1 crystallized in monoclinic space group P21/c, while compound 2 and 3 crystallized in triclinic space group P-1. The dinuclear compound 1 consists of two seven-coordinated Cd(II) centers which are doubly bridged by 2-OHbza bridging ligands, while the rest two 2-OHbza and two apm are terminal ligand. The crystal structure of compound 1 is stabilized by the intermolecular hydrogen bonding and C-H•••π interaction and π•••π interactions. Compounds 2 and 3 present zigzag one-dimensional chainlike-structure which dimer Cu(II) units are linked by apm ligand. The crystal structure of these compounds is stabilized by π•••π and C-H•••π interactions. The photoluminescence properties of compound 1 has been studied comparing to those of 2-OHbza and apm ligands. The solid state PL emission spectrum of compound 1 shows similar intensity of free apm ligand and shape to free 2-OHbza ligand which present a single broad band centered at λem 525 nm (λex = 325 nm), but blue-shift. For solution PL experiment of compound 1 in various solvents, the results showed that compound 1 is selective PL quenching acetone. Electronic spectra for solid state and solution in different solvents of compounds 2 and 3 present the d-d absorption bands centered in the range of 701 – 794 nm. The highest red shifts of λmax are found for compounds 2 and 3 in DMSO. In addition, the antibacterial activity of all compounds are investigated for S.aureus and E.coil by agar diffusion method. The results show that compound 1 exhibits the activity against S.aureus better than E.coil.

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Jahan, Mahmuda, Zillur Rahman, Nasrin Sultana, Mahmuda Begum, M. Shahab Uddin Ahamed et Syed Ahmed. « Cytomorphometric Analysis of Exfoliated Buccal Mucosal Cells in Diabetic Patients ». Chattagram Maa-O-Shishu Hospital Medical College Journal 19, n^o 1 (28 août 2020) : 3–7. http://dx.doi.org/10.3329/cmoshmcj.v19i1.48794.

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Background: Diabetes mellitus is a common metabolic disease that causeschronic hyperglycemia and disturbance in carbohydrate, lipid and proteinmetabolism. It causes various changes in the cells of the oral mucosa, which canbe determined by exfoliative cytology. The aim of this study was to study theCytomorphometric alterations of exfoliated buccal mucosal cells in diabeticpatients and to establish an additional diagnostic tool in diabetic patients inChattogram area. Materials and methods: It was a cross-sectional comparative study carried outin the Department of Pathology, Chattogram Medical College, Chattogram. Oralsmears were obtained from 88 diabetic patients and 88 healthy individuals. Thesmears were stained with Papanicolaou solution. The cell diameter and nucleardiameter of 50 clearly defined cells were measured by multi-head microscope(OLYMPUS B51X). The cytoplasmic area and nucleus-cytoplasmic ratio werethen calculated. SPSS software (version 17) was used for statistical analysis ofthe study. Results: In the result, mean Cell Diameter (CD), Nuclear Diameter (ND),cytoplasmic diameter (CyD) and N/C ratio of diabetic patients and healthy werefound to be 250.29 ± 29.02 μm, 54.48 ± 4.03 μm, 195.81 ± 27.97 μm, 0.283 ±0.04 and 287.15 ± 25.23 μm, 47.41 ± 2.52 μm, 239.74 ± 24.45 μm, 0.199 ± 0.02.A statistically significant increase in ND & N/C ratio and decrease in CD &CyDwere observed in diabetic patients compared to control. In addition, it wasfound that age, sex, blood sugar level, duration and treatment history ofdiabetes do not affect the morphometric changes significantly. Conclusions: Result of this study suggests that diabetes produces definitemorphometric changes in the exfoliated buccal mucosal cells. Exfoliativecytology can be useful as an additional tool to aid in diagnosis of diabetesmellitus. Chatt Maa Shi Hosp Med Coll J; Vol.19 (1); January 2020; Page 3-7

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Schaefer, Ted, James Peeling et Rudy Sebastian. « Solvent and α-substituent perturbations of the 2H/1H isotope shifts in the 13C nuclear magnetic resonance of toluene-α-d3 ». Canadian Journal of Chemistry 65, n^o 3 (1 mars 1987) : 534–37. http://dx.doi.org/10.1139/v87-093.

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The 2H/1H isotope effect on 13C nmr chemical shifts, nΔ, n being the number of intervening bonds between 2H and 13C nuclei, in toluene-α-d3 is solvent dependent. For example, 1Δ ranges from 817 ppb in CD3OH to 869 ppb in acetone-d6 solutions, a positive number indicating increased shielding in the deuterated species. 1Δ is linearly dependent on a function of the refractive index, nD, of the solvent, allowing extrapolation to nD = 1. The hyperconjugative model, in which the C—D bond is a poorer electron donor to the aromatic system than is a C—H bond, is tested for the substituents CH2D, CHD2, CD3, CHDCH3, CD2CH3, CD(CH3)2, C6H5CHD, and (C6H5)2CD. For these substituents, the negative 5Δ is linearly related to the expectation value of sin2 θ; θ is the angle by which the C—D bond twists out of the benzene plane. The model fails quantitatively for C6H5CD2X (X = Cl, COOH, CN, OH). For X = OH, very large negative 5Δ and 3Δ values are observed. nΔ is also reported for 4-ethyltoluene-α-d3 and benzaldehyde-α-d1. For the latter, all nΔ values are positive other than 5Δ, which vanishes in acetone-d6 solution.

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VREULS, Christelle, Patrice FILÉE, Hélène VAN MELCKEBEKE, Tony AERTS, Peter DE DEYN, Gabriel LLABRÈS, André MATAGNE, Jean-Pierre SIMORRE, Jean-Marie FRÈRE et Bernard JORIS. « Guanidinium chloride denaturation of the dimeric Bacillus licheniformis BlaI repressor highlights an independent domain unfolding pathway ». Biochemical Journal 384, n^o 1 (9 novembre 2004) : 179–90. http://dx.doi.org/10.1042/bj20040658.

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The Bacillus licheniformis 749/I BlaI repressor is a prokaryotic regulator that, in the absence of a β-lactam antibiotic, prevents the transcription of the blaP gene, which encodes the BlaP β-lactamase. The BlaI repressor is composed of two structural domains. The 82-residue NTD (N-terminal domain) is a DNA-binding domain, and the CTD (C-terminal domain) containing the next 46 residues is a dimerization domain. Recent studies have shown the existence of the monomeric, dimeric and tetrameric forms of BlaI in solution. In the present study, we analyse the equilibrium unfolding of BlaI in the presence of GdmCl (guanidinium chloride) using different techniques: intrinsic and ANS (8-anilinonaphthalene-l-sulphonic acid) fluorescence, far- and near-UV CD spectroscopy, cross-linking, analytical ultracentrifugation, size exclusion chromatography and NMR spectroscopy. In addition, the intact NTD and CTD were purified after proteolysis of BlaI by papain, and their unfolding by GdmCl was also studied. GdmCl-induced equilibrium unfolding was shown to be fully reversible for BlaI and for the two isolated fragments. The results demonstrate that the NTD and CTD of BlaI fold/unfold independently in a four-step process, with no significant co-operative interactions between them. During the first step, the unfolding of the BlaI CTD occurs, followed in the second step by the formation of an ‘ANS-bound’ intermediate state. Cross-linking and analytical ultracentrifugation experiments suggest that the dissociation of the dimer into two partially unfolded monomers takes place in the third step. Finally, the unfolding of the BlaI NTD occurs at a GdmCl concentration of approx. 4 M. In summary, it is shown that the BlaI CTD is structured, more flexible and less stable than the NTD upon GdmCl denaturation. These results contribute to the characterization of the BlaI dimerization domain (i.e. CTD) involved in the induction process.

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Wang, Wei, Xueqiu Wang, Bimin Zhang, Qiang Wang, Dongsheng Liu, Zhixuan Han, Sounthone LAOLO et al. « National-Scale Geochemical Baseline of 69 Elements in Laos Stream Sediments ». Minerals 12, n^o 11 (26 octobre 2022) : 1360. http://dx.doi.org/10.3390/min12111360.

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Geochemical baselines are crucial to explore mineral resources and monitor environmental changes. This study presents the first Laos geochemical baseline values of 69 elements. The National-scale Geochemical Mapping Project of Lao People’s Democratic Republic conducted comprehensive stream sediment sampling across Laos, yielding 2079 samples collected at 1 sample/100 km2, and 69 elements were analyzed. Based on the results of LGB value, R-mode factor analysis, and scatter plot analysis, this paper analyzes the relationship between the 69 elements and the geological background, mineralization, hypergene processes and human activities in the study area. The median values of element contents related to the average crustal values were: As, B, Br, Cs, Hf, Li, N, Pb, Sb, Zr, and SiO2, >1.3 times; Ba, Be, Cl, Co, Cr, Cu, F, Ga, Mn, Mo, Ni, S, Sc, Sr, Ti, Tl, V, Zn, Eu, Al2O3, Tot.Fe2O3, MgO, CaO, and Na2O, <0.7 times; and Ag, Au, Bi, Cd, Ge, Hg, I, In, Nb, P, Rb, Se, Sn, Ta, Th, U, W, Y, La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and K2O, 0.7–1.3 times. R-mode factor analysis based on principal component analysis and varimax rotation showed that they fall into 12 factors related to bedrock, (rare earth, ferrum-group, and major Al2O3 and K2O elements; mineralization–Au, Sb, and As) and farming activities–N, Br, S, and C). This study provides basic geochemical data for many fields, including basic geology, mineral exploration, environmental protection and agricultural production in Laos.

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Sasaki, Koji, Paul B. Koller, Hagop M. Kantarjian, Deborah A. Thomas, Maria R. Khouri, Guillermo Garcia-Manero, Rebecca Garris et al. « Phase II Study of the Frontline Hyper-CVAD in Combination with Ofatumumab for Adult Patients (pts) with CD-20 Positive Acute Lymphoblastic Leukemia (ALL) ». Blood 126, n^o 23 (3 décembre 2015) : 1295. http://dx.doi.org/10.1182/blood.v126.23.1295.1295.

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Abstract Background: The hyper-CVAD regimen is an effective frontline regimen for de novo adult ALL. Expression of CD20 was identified as an adverse prognostic factor, associated with a higher incidence of relapse, lower 3-year complete remission duration (CRD) and lower 3-year overall survival (OS) rate. The addition of rituximab to the hyper-CVAD regimen in pts with CD20-positive ALL (≥20% expression by multicolor flow cytometry - FCI) improved outcome with 3-year CRD and OS rates by 68% and 65%, respectively. Ofatumumab (HuMax-CD20) targets a membrane proximal small-loop epitope on the CD20 molecule and was found to be more potent than rituximab in promoting complement-dependent cytotoxicity in vitro. Ofatumumab's safety and efficacy has been proven in chronic lymphocytic leukemia. Therefore a combination of the hyper-CVAD regimen and ofatumumab may be associated with better response rates, higher 3-year CRD and overall survival rates. Methods: Pts with newly diagnosed ALL and pts who received one prior course of chemotherapy received 4 courses of hyper-CVAD (fractionated cyclophosphamide, vincristine [VCR], doxorubicin, dexamethasone; the odd courses 1, 3, 5, 7); ofatumumab was given on courses 1 and 3, and 4 courses of MTX-Ara-C (methotrexate-cytarabine; the even courses 2, 4, 6, 8); ofatumumab was given on courses 2 and 4. This treatment would be followed by POMP (6-mercaptopurine, MTX, VCR, prednisone) maintenance therapy for approximately 30 months, interrupted by intensifications months 6, 7 and 18, 19 with MTX/Pegylated asparaginase and hyper-CVAD-ofatumumab. Central nervous system prophylaxis with MTX and ara-C was administered. When indicated local radiotherapy was administered in patients with bulky mediastinal disease Results: To date 37 pts with de novo ALL and 4 pts in complete remission (CR) previously treated (2 with prior cycle of hyper-CVAD, 1 post fludarabine-cytarabine based regimen, 1 with cyclophosphamide and dexamethasone) have received a median of 6 cycles (1-8) of therapy. Median age is 46 years (32-71). Median WBC at diagnosis was 5.4 x 109/L (1 -202 x 109/L). CD20 expression above 20% was found in 27 pts (66%), between 10 and 20% in 3 (7%) and below 10% in 11 (27%). 2 pts (5%) had concomitant CNS disease at diagnosis. Among the 34 pts with evaluable baseline cytogenetic analysis, 20 (49%) were abnormal. All but one pt (97%) achieved a CR after cycle 1 (4 pts were in CR at the start); 1 pt died of septic shock and multiple organ failure at day 21 of cycle 1. Thirty-eight (95%) pts achieved minimal residual disease (MRD) negativity as assessed by FCI; of whom 23 (64%) achieved MRD negativity after induction. Ten (27%) pts did not receive the full 8 planned courses of induction-consolidation; 16 (43%) pts are receiving maintenance in CR; 4 (11%) pts finished all treatment; 5 (%) pts were referred to allogeneic stem cell transplantation due to multiple cytogenetic abnormalities and delay in achieving negative MRD. Median time to neutrophil and platelet recovery for cycle 1 was 18 and 22 days after induction chemotherapy, respectively. Grade ≥ 3 toxicity included increase of LFT's in 13 pts (32%), increase of bilirubin in 7 (17%), nausea/vomiting in 4 (10%), mucositis in 3 (7%), neuropathy in 3 (7%), and thrombotic events in 1 (2%). Febrile neutropenia episodes during induction and consolidation cycles were reported at rates of 67% and 89%, respectively. With a median follow up of 15 months (1-45), 35 pts are alive; 6 pts relapsed and one had molecular relapse only. Six pts died: 1 at C1D22 of sepsis and intracranial bleed; 1 at C3D17 of sepsis and multiple organ failure; 1 at maintenance C16D35 of sepsis; 1 of relapse post ASCT; 1 post salvage therapy for minimal residual disease relapse; 1 of progressive disease after relapse. The 2-year PFS and OS rates were 68% and 87% respectively. Conclusion: The combination of hyper-CVAD with ofatumumab is safe and highly effective in pts with CD20-positive ALL. Table 1. Patient characteristics and outcome N (%)/Median [range] N=41 Age (yrs) 44 [22-71] Sex Male 25 (61) Female 16 (39) PS 0-1 38 (93) 2-3 3 (7) WBC (x 109/L) 5.4 [0.7-201.7] CNS disease positivity 2 (5) CD20 + (%) 1-10 9 (22) 10-20 3 (7) >20 27 (66) Pos 2 (5) CG Diploid 14 (34) Abnormal 20 (49) IM/ND 7 (17) Response CR 37/38 (97) CR after induction 37/38 (97) MRD at CR 23/36 (64) MRD overall 38/40 (95) Early death 1 (3) Figure 1. Progression-free survival and overall survival Figure 1. Progression-free survival and overall survival Disclosures Cortes: Teva: Research Funding; BerGenBio AS: Research Funding; Pfizer: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; Ariad: Consultancy, Research Funding; BMS: Consultancy, Research Funding; Astellas: Consultancy, Research Funding; Ambit: Consultancy, Research Funding; Arog: Research Funding; Celator: Research Funding; Jenssen: Consultancy. Chahoud:American Society of Hematology (ASH): Other: 2015 HONORS Award recipient. Verstovsek:Incyte Corporation: Research Funding. Konopleva:Novartis: Research Funding; AbbVie: Research Funding; Stemline: Research Funding; Calithera: Research Funding; Threshold: Research Funding. O'Brien:Pharmacyclics LLC, an AbbVie Company: Consultancy, Research Funding.

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Kicková, Anna, Branislav Horváth, Lukáš Kerner et Martin Putala. « Synthesis and properties of macrocyclic diazene switch with binaphthalene unit attached via acrylamide linkers ». Chemical Papers 67, n^o 1 (1 janvier 2013). http://dx.doi.org/10.2478/s11696-012-0247-y.

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Abstract2,2′-Diiodo-1,1′-binaphthalene undergoes a tandem Heck reaction with methyl acrylate to afford methyl 2-(7H-dibenzo[c,g]fluoren-7-ylidene)acetate. As a consequence, the target macrocyclic diazene with binaphthalene unit attached via acrylamide linker was prepared by the stepwise building of acrylamide at a binaphthalene moiety, including the Doebner modification of the Knoevenagel condensation, and completed by oxidative macrocyclisation of aniline end-groups. Despite being an equimolar mixture of monomer and dimer, it exhibited remarkable changes in CD spectra due to reversible (E/Z) isomerisation of N=N diazene bonds upon irradiation at 365/465 nm. Although the dimer isomerises from (E) to (Z) isomer 7.4 times faster than the monomer, the latter’s contribution to the change in ellipticity at 307 nm in the photostationary state is 2.4 times greater.

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Patel, Ritika M., et Ridhdhish K. Patel. « Comparative Cytomorphometric Study of Exfoliated Squamous Buccal Cells among Patients with Iron Deficiency Anaemia and Healthy Individuals in Saurashtra, Gujarat, India ». INTERNATIONAL JOURNAL OF ANATOMY RADIOLOGY AND SURGERY, 2022. http://dx.doi.org/10.7860/ijars/2022/55633.2829.

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Introduction: Cytology is a fast, simple, non invasive, and bloodless procedure. Cytology can be useful in cases where biopsy is contraindicated or not needed, such as in systemically compromised patients, inaccessible areas, recurrent malignancies and mass screening. The most common nutritional disorder in the world is iron deficiency and it is more prevalent in India. Exfoliative cytology is becoming increasingly recognized as a standard technique for screening oral pathologies like anaemia. Aim: To compare the Nucleus Diameters (ND), the Cytoplasmic Diameters (CD), and the Nucleus/Cytoplasmic ratio (N/C) in cytological buccal smears of iron deficiency anaemic patients and with normal healthy individuals. Materials and Methods: The case-control study was conducted in Department of Anatomy, G.G hospital connected MP Shah Government Medical College, Jamnagar, Gujarat, India, from August 2013 to February 2016, which included 50 healthy individuals and 50 clinically diagnosed patients of iron deficiency anaemia. Exfoliated buccal smears stained with routine Haematoxyline and Eosin staining technique. With the use of ocular micrometer, CD, ND and N/C ratio were calculated. All the parameters were statistically evaluated by using Student t-test. Results: The mean value of nuclear diameter 11.34±0.58 μm and N/C ratio (0.24±0.02) of buccal mucosa was greater while cytoplasmic diameter 46.57±2.03 μm was lesser in iron deficiency anaemia when compared with healthy individuals. A significant difference was not found when comparing different age groups, as well as male versus female cases and male versus female controls. Comparing cases and controls by gender, however produced significant statistical results. Conclusion: Statistically significant difference was found between iron deficiency anaemia patients and normal healthy individuals regarding changes in various parameters of buccal squamous cells. In the case of iron deficiency anaemia, oral exfoliative cytological techniques could be used as an alternative non invasive diagnostic tool.

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Licht, Otavio Augusto Boni, Xie Xuejing, Zhang Qin, Mario Miyazawa, Francisco José Fonseca Ferreira et Rafael André Belotto Plawiak. « VALORES MÉDIOS DE REFERÊNCIA DE VARIÁVEIS GEOQUÍMICAS E GEOFÍSICAS EM SEDIMENTOS DE DRENAGEM E SOLOS, ESTADO DO PARANÁ, BRASIL ». Boletim Paranaense de Geociências 58 (31 décembre 2006). http://dx.doi.org/10.5380/geo.v58i0.10714.

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A coleta de 696 amostras de sedimentos de drenagem e 307 de solo – horizonte B, segundo ospadrões estabelecidos pelos Projetos IGCP-259 e IGCP-360 (UNESCO e IUGS), e a determinação de variáveisgeoquímicas, geofísicas e de fertilidade de solos nas amostras compostas representando as célulasGlobal Geochemical Reference Network (GGRN) permitiram a constituição de uma robusta base de dadoscobrindo os 200.000 km2 do Estado do Paraná, na região Sul do Brasil. As 39 amostras representativas decélulas GGRN de sedimentos ativos de drenagem foram analisadas para Ag, Al2O3, As, Au, B, Ba, Be, Bi, Br,CaO, Cd, Ce, Cl, Co, Corgânico, Cr, Cs, Ctotal, Cu, Dy, Er, Eu, F, Fe2O3, Ga, Gd, Ge, Hg, Ho, I, K2O, La, Li, Lu, MgO, Mn,Mo, N, Na2O, Nb, Nd, Ni, P, Pb, Pd, Pr, Pt, Rb, S, Sb, Sc, Se, SiO2, Sm, Sn, Sr, Tb, Te, Th, Ti, Tl, Tm, U, V, W, Y, Yb,Zn. As 43 amostras representativas de células GGRN de solos – horizonte B foram analisadas para Ag, Al2O3, As, Au, B, Ba, Be, Bi, Br, CaO, Cd, Ce, Cl, Co, Cr, Cs, Cu, Dy, Er, Eu, F, Fe2O3, Ga, Gd, Ge, Hf , Hg, Ho, I, In, K2O,La, Li, Lu, MgO, Mn, Mo, N, Na2O, Nb, Nd, Ni, P, Pb, Pd, Pr, Pt, Rb, S, Sb, Sc, Se, SiO2, Sm, Sn, Sr, Ta, Tb, Th, Ti,Tl, Tm, U, V, W, Y, Yb, Zn, Zr. Nas 307 amostras originais de solo – horizonte B foram determinados parâmetrosde fertilidade de solos Al, Altrocável, Cadisponível, Mgdisponível, Btrocável, C, Cutrocável, Zntrocável, Fetrocável, H+ + Al3+, Mntrocável,Pdisponível, Kdisponível, pH, Strocável, Zntrocável, V , S, T, bem como a suscetibilidade magnética e contagem total, eU, eThe K por gamaespectrometria. Os valores médios dessas variáveis no território paranaense, assim como suacomparação com as médias globais para a superfície terrestre, permitiram estabelecer valores de referênciaque poderão ser utilizados em pesquisas multipropósito de geologia, exploração mineral, delimitação deáreas de risco à saúde humana, fauna e flora, planejamento agrícola e monitoramento ambiental. O conteúdodessa base de dados, que descreve algumas características ambientais do território paranaense, representauma primeira abordagem em escala regional que servirá como referência tanto para estudos localizadose de maior detalhe no estado do Paraná quanto para a investigação do território de outros estadosbrasileiros ou mesmo dos países limítrofes.

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