Time-resolved photoluminescence of n-doped SrTiO_3

Following the recent surge of interest in n-doped strontium titanate as a possible blue light emitter, a time-resolved photoluminescence analysis was performed on nominally pure, Nb-doped and oxygen-deficient single-crystal SrTiO3 samples. The doping-effects on both the electronic states involved in the transition and the decay mechanism are respectively analyzed by comparing the spectral and dynamic features and the yields of the emission. Our time-resolved analysis, besides shedding some light on the basic recombination mechanisms acting in these materials, sets the intrinsic bandwidth limit of the proposed blue light emitting optoelectronic devices made of Ti-based perovskites heterostructures in the GHz range

Transport in strongly-coupled graphene-LaAlO3/SrTiO3 hybrid systems

We report on the transport properties of hybrid devices obtained by depositing graphene on a LaAlO3/SrTiO3 oxide junction hosting a 4 nm-deep two-dimensional electron system. At low graphene-oxide inter-layer bias the two electron systems are electrically isolated, despite their small spatial separation, and very efficient reciprocal gating is shown. A pronounced rectifying behavior is observed for larger bias values and ascribed to the interplay between electrostatic depletion and tunneling across the LaAlO3 barrier. The relevance of these results in the context of strongly-coupled bilayer systems is discussed.Comment: 10 pages, 3 figure

Second international diagnostic accuracy study for the serological detection of west nile virus infection.

Background: In recent decades, sporadic cases and outbreaks in humans of West Nile virus (WNV) infection have increased. Serological diagnosis of WNV infection can be performed by enzyme-linked immunosorbent assay (ELISA), immunoflu- orescence assay (IFA) neutralization test (NT) and by hemagglutination-inhibition assay. The aim of this study is to collect updated information regarding the performance accuracy of WNV serological diagnostics. Methodology/Principal findings: In 2011, the European Network for the Diagnostics of Imported Viral Diseases- Collaborative Laboratory Response Network (ENIVD-CLRN) organized the second external quality assurance (EQA) study for the serological diagnosis of WNV infection. A serum panel of 13 samples (included sera reactive against WNV, plus specificity and negative controls) was sent to 48 laboratories involved in WNV diagnostics. Forty-seven of 48 laboratories from 30 countries participated in the study. Eight laboratories achieved 100% of concurrent and correct results. The main obstacle in other laboratories to achieving similar performances was the cross-reactivity of antibodies amongst heterologous flaviviruses. No differences were observed in performances of in-house and commercial test used by the laboratories. IFA was significantly more specific compared to ELISA in detecting IgG antibodies. The overall analytical sensitivity and specificity of diagnostic tests for IgM detection were 50% and 95%, respectively. In comparison, the overall sensitivity and specificity of diagnostic tests for IgG detection were 86% and 69%, respectively. Conclusions/Significance: This EQA study demonstrates that there is still need to improve serological tests for WNV diagnosis. The low sensitivity of IgM detection suggests that there is a risk of overlooking WNV acute infections, whereas the low specificity for IgG detection demonstrates a high level of cross-reactivity with heterologous flaviviruse

Ruthenium (0) complexes with NHC tetrazolylidene ligands: Synthesis, characterization and reactivity

Here we present two new phenyl-tetrazolylidene carbenes as ligands in non-mesoionic (1,4-substitution pattern) and mesoionic (1,3-substitution pattern) tetrazolylidene-cyclopentadienone ruthenium(0) complexes namely 1 and 2 respectively. The complexes have been obtained in good yield and fully characterized; X-ray structure determination confirmed the binding mode of the ligand for 2. Reactivity studies has been performed in order to shed light on the fact that the phenyl substituent position in the heterocyclic ligand can seriously change complexes behavior and stabilit

4-Phenyl-1,2,3-triazoles as Versatile Ligands for Cationic Cyclometalated Iridium(III) Complexes

Five cationic iridium(III) complexes (1-5) were synthesized exploiting two triazole-based cyclometalating ligands, namely, 1-methyl-4-phenyl-1H-1,2,3-triazole (A) and the corresponding mesoionic carbene 1,3-dimethyl-4-phenyl-1H-1,2,3-triazol-5-yliclene (B). From the combination of these two ligands and the ancillary one, i.e., 4,4'-di-tert-butyl-2,2'-bipyridine (for 1-3) or tert-butyl isocyanide (for 4 and 5), not only the typical bis-heteroleptic complexes but also the much less explored tris-heteroleptic analogues (2 and 5) could be synthesized. The redox and emission properties of all of the complexes are effectively fine-tuned by the different ligands: (i) cyclometalating ligand A induces a stronger highest occupied molecular orbital (HOMO) stabilization compared to B and leads to complexes with progressively narrower HOMO-lowest unoccupied molecular orbital (LUMO) and redox gaps, and lower emission energy; (ii) complexes 1-3, equipped with the bipyridine ancillary ligand, display fully reversible redox processes and emit from predominantly metal-to-ligand charge transfer (MLCT) states with high emission quantum yields, up to 60% in polymeric matrix; (iii) complexes 4 and 5, equipped with high-field isocyanide ligands, display irreversible redox processes and high-energy emission from strongly ligand-centered triplets with long emission lifetimes but relatively low quantum yields (below 6%, both in room-temperature solution and in solid state). This work demonstrates the versatility of phenyl-triazole derivatives as cyclometalating ligands with different chelation modes (i.e., C<^>N and C<^>C:) for the synthesis of photoactive iridium(III) complexes with highly tunable properties

Chikungunya virus (CHIKV) infection: Analytical performance of real-time NASBA assay

n/

A new computerized tomography classification to evaluate response to Denosumab in giant cell tumors in the extremities

Objectives: The aim of this study was to describe the cohort of patients who have been treated with Denosumab as neoadjuvant therapy prior to surgery for aggressive giant cell tumor of bone in the extremities, to evaluate the radiological responses to Denosumab comparing Choi criteria and a newly described computerized tomography (CT) classification, and to evaluate the risk of local recurrence after intralesional curettage or radical excision. Methods: We retrospectively evaluated 36 patients (20 females and 16 males; mean age at diagnosis 36 years (range, 18\u201364)) treated with neoadjuvant Denosumab therapy prior to surgery for aggressive giant cell tumor of bone in the extremities. The radiological responses to Denosumab treatment were analyzed on the preoperative images after the neoadjuvant course with the Choi criteria and with a newly proposed classification based on CT. All these images were independently reviewed by two of the researchers. Surgical intervention methods were noted and local recurrence rates were evaluated. The correlation between radiological response amount and local recurrence were analyzed for both Choi criteria and the new CT classification. Results: Denosumab was administered for a mean of 21 weeks (range 7\u2013133). Five patients also had a short postoperative course. According to Choi criteria there was a radiological response in 32 patients (89%), while the new CT classification identified responses in all the 36 patients (100%). The identification of changes after 7 weeks of treatment was higher using the CT classification compared to Choi criteria (p = 0.043 vs p = 0.462). The surgical interventions after Denosumab comprised curettage in 29 patients (74%) and resection in 7 (26%). Local recurrence was higher in patients managed with intralesional curettage than in those treated with en bloc resection (55.1% vs 0%, p < 0.001). At last follow up 19 patients (53%) required en bloc resections. Good responders to Denosumab (type 2C) had lower risk of local recurrence (p = 0.047) after either resection or curettage. Conclusion: The new CT classification evaluated more accurately the response to Denosumab. Our experience suggests that the requirement for radical bone resection remains high despite the use of Denosumab. Level of evidence: Level IV, Therapeutic Study

Analysis and characterization of mouse monoclonal antibodies reactive to Chikungunya virus (CHIKV)

occurring in 1984). However, plague has made an astonishing comeback in the last decade. Methods: n/a. Results: After a silence of 50 years, an outbreak of bubonic plague suddenly occurred close to Oran in Algeria, in June 2003. Eighteen bubonic cases were identified, and Yersinia pestis was isolated from 6 patients. In July 2008, a new cluster was reported among nomads 300 km south of the first one. Four members of one family were affected and one died. The bacillus was isolated from one patient. No epidemiological association was identified between the two events. On June 2009, 25 years after the last occurrence in the country, Libya reported five confirmed cases of bubonic plague in the Tobruk area. Y. pestis was isolated from three patients. In all these cases, further local ecological investigations confirmed the existence of a natural focus The re-emergence of human plague in the region is not without international consequences. Two of the last concerned natural foci are close to an international port which raises the question of the potential exportation of infected rodents. Cross-border tensions, between ''plague countries'' and ''plague-free countries'' have been observed although the foci's limits are unknown as any systematic ecological investigation and surveillance is lacking. Additionally, the potential weaponization of Y.pestis together with international political tensions feed a recurrent interest in plague in North Africa. False rumors of alleged military laboratory accidents or terrorist acts are routinely mentioned, although events could be first explained by the natural history of the disease. Conclusion: In this context, and although the number of human cases has been very limited so far, the first priorities are to establish appropriate ecological surveillance and agree on a common plague control strategy for the region

Comparative genomic and phylogenetic analysis of the first usutu virus isolate from a human patient presenting with neurological symptoms.

Usutu virus (USUV) is a mosquito-borne flavivirus, belonging to the Japanese encephalitis antigenic complex, that circulates among mosquitoes and birds. We describe and analyze the complete genome sequence of the first USUV strain isolated from an immunocompromised patient with neuroinvasive disease. This USUV isolate showed an overall nucleotide identity of 99% and 96%, respectively, with the genomes of isolates from Europe and Africa. Comparison of the human USUV complete polyprotein sequence with bird-derived strains, showed two unique amino acid substitutions. In particular, one substitution (S595G) was situated in the DIII domain of the viral Envelope protein that is recognized by flavivirus neutralizing antibodies. An additional amino acid substitution (D3425E) was identified in the RNA-dependent RNA polymerase (RdRp) domain of the NS5 protein. This substitution is remarkable since E3425 is highly conserved among the other USUV isolates that were not associated with human infection. However, a similar substitution was observed in Japanese encephalitis and in West Nile viruses isolated from humans. Phylogenetic analysis of the human USUV strain revealed a close relationship with an Italian strain isolated in 2009. Analysis of synonymous nucleotide substitutions (SNSs) among the different USUV genomes showed a specific evolutionary divergence among different countries. In addition, 15 SNSs were identified as unique in the human isolate. We also identified four specific nucleotide substitutions in the 59 and 39 untranslated regions (UTRs) in the human isolate that were not present in the other USUV sequences. Our analyses provide the basis for further experimental studies aimed at defining the effective role of these mutations in the USUV genome, their potential role in the development of viral variants pathogenic for humans and their evolution and dispersal out of Africa

Iridium-Functionalized Cellulose Microcrystals as a Novel Luminescent Biomaterial for Biocomposites

Microcrystalline cellulose (MCC) is an emerging material with outstanding properties in many scientific and industrial fields, in particular as an additive in composite materials. Its surface modification allows for the fine-tuning of its properties and the exploitation of these materials in a plethora of applications. In this paper, we present the covalent linkage of a luminescent Ir-complex onto the surface of MCC, representing the first incorporation of an organometallic luminescent probe in this biomaterial. This goal has been achieved with an easy and sustainable procedure, which employs a Bronsted-acid ionic liquid as a catalyst for the esterification reaction of -OH cellulose surface groups. The obtained luminescent cellulose microcrystals display high and stable emissions with the incorporation of only a small amount of iridium (III). Incorporation of MCC-Ir in dry and wet matrices, such as films and gels, has been also demonstrated, showing the maintenance of the luminescent properties even in possible final manufacturers