206 research outputs found
ELISA - Experimental Large Italian Seismic Array
The Italian Seismic Network (ISN) operated by the INGV consists of more than 200 seismic stations and has recently been upgraded by some dozen broadband seismic stations (Nanometrics Trident 24 bit digitizers, Trillium seismometers). Real time data acquisition at Central Data Analysis Centre at the INGV-Rome is realized by satellite data transmission (Libra VSAT)
On the ambiguity of 1,3,2-benzodiazaboroles as donor/acceptor functionalities in luminescent molecules
A series of 1,3-bis(perfluoroaryl)-2-(hetero)aryl-1,3,2-benzodiazaboroles, 1,3-FAr2-2-Ar-1,3,2-N2BC6H4 (Ar = Ph, FAr = C6F5 5; Ar = Ph, FAr = 4-C5F4N 6; Ar = Ph, FAr = 4-NCC6F4 7; Ar = 2-C4H3S, FAr = C6F5 8; Ar = 2-C4H3S, FAr = 4-C5F4N 9; Ar = 2-C4H3S, FAr = 4-NCC6F4 10), were synthesised by cyclocondensation of the adducts PhBBr2·PPh3 or 2-thienylBBr2·PPh3 with N,N′-bis(perfluoroaryl)-o-phenylenediamines in the presence of 2,2,6,6-tetramethylpiperidine. Similar treatments of the PPh3 adducts of 4-(1′,3′-diethyl-1′,3′,2′-benzodiazaborolyl)-phenyldibromoborane with the corresponding diamines gave rise to the push–pull compounds, C6H4(NEt)2B-1,4-C6H4-B(NFAr)2C6H4 (FAr = C6F5 11; 4-C5F4N 12) and C6H4(NEt)2B-2,5-C4H2S-B(NFAr)2C6H4 (FAr = C6F5 13; 4-C5F4N 14). The X-ray structures of 8, 11, 12 and 13 were determined. Electronic structure calculations reveal that the LUMOs are located at the perfluoroaryl groups in 5–14; thus the fluorinated benzodiazaborolyl groups are considered as electron-withdrawing moieties. These moieties differ from alkylated benzodiazaborolyl groups which are regarded as donors. The emission spectra for 5–14 show charge transfer bands with significant solvatochromism and large Stokes shifts (6100–12500 cm−1 in cyclohexane and 8900–15900 cm−1 in CH2Cl2). The emissions of the benzodiazaboroles, 5–10, arise from a different charge transfer (CT) process to the local charge transfer (LCT) process typically found in many fluorescent benzodiazaboroles. This novel remote charge transfer (RCT) process involving the perfluoroaryl groups is supported by CAM-B3LYP computations. The push–pull systems 11–14 here give fluorescent emissions with moderate to high fluorescence quantum yields (65–97%) that arise from the usual LCT process only
Isolation of singlet carbene derived 2-phospha-1,3-butadienes and their sequential one-electron oxidation to radical cations and dications
A synthetic strategy for the 2-phospha-1,3-butadiene derivatives [{(IPr)C(Ph)}P(cAAC)] (3a) and [{(IPr)C(Ph)}P(cAAC)] (3b) (IPr = C{(NDipp)CH}, Dipp = 2,6-iPrCH; cAAC = C{(NDipp)CMeCHCMe}; cAAC = C{(NDipp)CMeCHC(Cy)}, Cy = cyclohexyl) containing a C=C–P=C framework has been established. Compounds 3a and 3b have a remarkably small HOMO–LUMO energy gap (3a: 5.09; 3b: 5.05 eV) with a very high-lying HOMO (-4.95 eV for each). Consequently, 3a and 3b readily undergo one-electron oxidation with the mild oxidizing agent GaCl to afford radical cations [{(IPr)C(Ph)}P(cAAC)]GaCl (R = Me 4a, Cy 4b) as crystalline solids. The main UV-vis absorption band for 4a and 4b is red-shifted with respect to that of 3a and 3b, which is associated with the SOMO related transitions. The EPR spectra of compounds 4a and 4b each exhibit a doublet due to coupling of the unpaired electron with the P nucleus. Further oneelectron removal from the radical cations 4a and 4b is also feasible with GaCl, affording the dications [{(IPr)C(Ph)}P(cAAC)](GaCl) (R = Me 5a, Cy 5b) as yellow crystals. The molecular structures of compounds 3–5 have been determined by X-ray diffraction and analyzed by DFT calculations
Metalloradical Cations and Dications Based on Divinyldiphosphene and Divinyldiarsene Ligands
Metalloradicals are key species in synthesis, catalysis, and bioinorganic chemistry. Herein, two iron radical cation complexes (3‐E)GaCl [(3‐E) = [{(IPr)C(Ph)E}Fe(CO)], E = P or As; IPr = C{(NDipp)CH}, Dipp = 2,6‐iPrCH] are reported as crystalline solids. Treatment of the divinyldipnictenes {(IPr)C(Ph)E} (1‐E) with Fe(CO) affords [{(IPr)C(Ph)E}Fe(CO)] (2‐E), in which 1‐E binds to the Fe atom in an allylic (η‐EEC) fashion and functions as a 4e donor ligand. Complexes 2‐E undergo 1e oxidation with GaCl to yield (3‐E)GaCl. Spin density analysis revealed that the unpaired electron in (3‐E).+ is mainly located on the Fe (52–64 %) and vinylic C (30–36 %) atoms. Further 1e oxidation of (3‐E)GaCl leads to unprecedented η‐EEC to η‐ECC coordination shuttling to form the dications (4‐E)(GaCl)
The diagnostic value of ultrasonography-derived edema of the temporal artery wall in giant cell arteritis: a second meta-analysis
<p>Abstract</p> <p>Background</p> <p>Ultrasonography of temporal arteries is not commonly used in the approach of patients with suspected giant cell arteritis (GCA) in clinical practice. A meta-analysis of primary studies available through April 2004 concluded that ultrasonography could indeed be helpful in diagnosing GCA. We specifically re-examined the diagnostic value of the ultrasonography-derived halo sign, a dark hypoechoic circumferential thickening around the artery lumen, indicating vasculitic wall edema, in GCA.</p> <p>Methods</p> <p>Original, prospective studies in patients with suspected GCA that examined ultrasonography findings of temporal arteries using the ACR 1990 classification criteria for GCA as reference standard, published through 2009, were identified. Only eight studies involving 575 patients, 204 of whom received the final diagnosis of GCA, fulfilled technical quality criteria for ultrasound. Weighted sensitivity and specificity estimates of the halo sign were assessed, their possible heterogeneity was investigated and pooled diagnostic odds ratio was determined.</p> <p>Results</p> <p>Unilateral halo sign achieved an overall sensitivity of 68% (95% CI, 0.61-0.74) and specificity of 91% (95% CI, 0.88-0.94) for GCA. The values of inconsistency coefficient (I<sup>2</sup>) of both sensitivity and specificity of the halo sign, showed significant heterogeneity concerning the results between studies. Pooled diagnostic odds ratio, expressing how much greater the odds of having GCA are for patients with halo sign than for those without, was 34 (95% CI, 8.21-138.23). Diagnostic odds ratio was further increased to 65 (95% CI, 17.86-236.82) when bilateral halo signs were present (sensitivity/specificity of 43% and 100%, respectively). In both cases, it was found that DOR was constant across studies.</p> <p>Conclusion</p> <p>Temporal artery edema demonstrated as halo sign should be always looked for in ultrasonography when GCA is suspected. Providing that currently accepted technical quality criteria are fulfilled, halo sign's sensitivity and specificity are comparable to those of autoantibodies used as diagnostic tests in rheumatology. Validation of revised GCA classification criteria which will include the halo sign may be warranted.</p
Temporal and structural genetic variation in reindeer (Rangifer tarandus) associated with the pastoral transition in Northwestern Siberia
Funding Information NordForsk. Grant Number: 76915 ERC Advanced Grant. Grant Numbers: 295458, ESRC ES/, M011054/1 JPI HUMANOR ERC Starting GrantPeer reviewedPublisher PD
Fungicide-Driven Evolution and Molecular Basis of Multidrug Resistance in Field Populations of the Grey Mould Fungus Botrytis cinerea
The grey mould fungus Botrytis cinerea causes losses of commercially important fruits, vegetables and ornamentals worldwide. Fungicide treatments are effective for disease control, but bear the risk of resistance development. The major resistance mechanism in fungi is target protein modification resulting in reduced drug binding. Multiple drug resistance (MDR) caused by increased efflux activity is common in human pathogenic microbes, but rarely described for plant pathogens. Annual monitoring for fungicide resistance in field isolates from fungicide-treated vineyards in France and Germany revealed a rapidly increasing appearance of B. cinerea field populations with three distinct MDR phenotypes. All MDR strains showed increased fungicide efflux activity and overexpression of efflux transporter genes. Similar to clinical MDR isolates of Candida yeasts that are due to transcription factor mutations, all MDR1 strains were shown to harbor activating mutations in a transcription factor (Mrr1) that controls the gene encoding ABC transporter AtrB. MDR2 strains had undergone a unique rearrangement in the promoter region of the major facilitator superfamily transporter gene mfsM2, induced by insertion of a retrotransposon-derived sequence. MDR2 strains carrying the same rearranged mfsM2 allele have probably migrated from French to German wine-growing regions. The roles of atrB, mrr1 and mfsM2 were proven by the phenotypes of knock-out and overexpression mutants. As confirmed by sexual crosses, combinations of mrr1 and mfsM2 mutations lead to MDR3 strains with higher broad-spectrum resistance. An MDR3 strain was shown in field experiments to be selected against sensitive strains by fungicide treatments. Our data document for the first time the rising prevalence, spread and molecular basis of MDR populations in a major plant pathogen in agricultural environments. These populations will increase the risk of grey mould rot and hamper the effectiveness of current strategies for fungicide resistance management
The anthropology of extraction: critical perspectives on the resource curse
Attempts to address the resource curse remain focussed on revenue management, seeking technical solutions to political problems over examinations of relations of power. In this paper, we provide a review of the contribution anthropological research has made over the past decade to understanding the dynamic interplay of social relations, economic interests and struggles over power at stake in the political economy of extraction. In doing so, we show how the constellation of subaltern and elite agency at work within processes of resource extraction is vital in order to confront the complexities, incompatibilities, and inequities in the exploitation of mineral resources
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