Tuning the optoelectronic properties of PEDOT:PSS-PVP core-shell electrospun nanofibers by solvent-quantum dot doping and phase inversion.

In the present study core-shell PEDOT:PSS-polyvinylpirrolidone nanofibers were synthesized by coaxial electrospinning. These fibers were doped with different solvents (dimethylsulphoxide, dimethyl sulfoxide (DMSO), isopropyl alcohol (IPA), and ethylene glycol), and PbS nanoparticles at different concentrations; additionally, the coaxial electrospinning setup process was inverted in order to exchange the phases comprising the core-shell morphology. Experimental results showed that DMSO and IPA solvents produced a change in the PEDOT:PSS phase from its benzoid structure to a more conjugated (quinoid) one. The synthesized samples displayed an increment in the conductance of the composite nanofibers, based on a more conjugated structure of the PEDOT:PSS phase, and a better dispersion of the PbS nanoparticles within the nanofibers; this increment was, under certain synthesis conditions, up to three orders of magnitude higher than in the case of the nanofibers with no solvent, nor nanoparticles, added. Photoresponse also showed a clear increment in the value of the photogenerated current as the concentration of the nanoparticles increased. Inverting the arrangement of the core-shell phases in the nanofibers increased the conductance and the photogenerated current in the cases analyzed. These results show novel evidence on the capability of tuning the conductance and photoresponse of composite core-shell nanofibers, based on the doping of the PEDOT:PSS phase with different solvents and PbS nanoparticles, and the arrangement of the core-shell phases. Tailoring the optoelectronic properties of conductive, flexible nanofibers is a desirable competence in technological areas such as transparent flexible conductors, biosensors and tissue engineering.

Silver/polysaccharide-based nanofibrous materials synthesized from green chemistry approach.

In this contribution a novel green chemistry approach for the synthesis of nanofibrous materials based on blends of carboxymethyl-cellulose (CMC)-silver nanoparticles (AgNPs) composite and polyvinyl-alcohol (PVA) is proposed. These nanofibrous materials were obtained from the electrospinning of blends of aqueous solutions of CMC-AgNPs composite and PVA, which were prepared at different CMC/PVA weight ratios in order to electrospin nanofibers applying a constant tension of 15kV. The synthesized materials were characterized by means of transmission electron microscopy, scanning electron microscopy; as well as Fourier-transform infrared, ultraviolet and Raman spectroscopic techniques. Experimental evidence suggests that the diameter of the nanofibers is thinner than any other reported in the literature regarding the electrospinning of CMC. This feature is related to the interactions of AgNPs with carboxyl functional groups of the CMC, which diminish those between the later and acetyl groups of PVA.

Rupestris stem pitting associated virus isolates are composed by mixtures of genomic variants which share a highly conserved coat protein.

Broad spectrum primers were used to amplify a fragment comprising the CP gene and putative ORF6 by RT-PCR from ds-RNA templates originating from 46 Portuguese varieties, totalling 190 samples, including some wild Vitis ssp sylvestris vines, and 2 vines from Slovenia. SSCP analysis was used as a preliminary screen to avoid cloning and sequencing very similar variants. Four groups of variants were recognized. In pair wise comparisons between nucleotide sequences the minimal homology found was 81%. In case of the cultivated varieties, no relationship could be seen between the phylogenetic groups and geographic origin or grape variety. Several isolates were found harbouring mixed infections with genomic variants from different groups, but the mixing did not lead to an extensive recombination between them. The deduced amino-acid sequences revealed a conserved CP subjected to strong purifying selection pressure. Analysis of the selection pressure operating on the putative ORF6 suggests that this ORF does not exist. Previously produced polyclonal antiserum raised against the recombinant CP of RSPaV expressed in Escherichia coli was shown to be able to detect all four groups of variants of RSPaV included in this study, which might enable the diagnosis of the virus on a serological basis.

Genetic organisation of Iris yellow spot virus M RNA: indications for functional homology between the G(C) glycoproteins of tospoviruses and animal-infecting bunyaviruses.

The complete nucleotide sequence (4838 nucleotides) of Iris yellow spot virus (IYSV) M RNA indicates, typical for tospoviruses, the presence of two genes in ambisense arrangement. The vRNA ORF codes for the potential cell-to-cell movement (NSm) protein (34.8 kDa) and the vcRNA ORF for the viral glycoprotein (G1/G2) precursor (128.6 kDa). Multiple sequence alignment of the NSm and G1/G2 precursor proteins of IYSV with those of other tospoviruses, showed highest homologies to Peanut bud necrosis virus (PBNV) and Watermelon silver mottle virus (WSMV). The potential cell-to-cell movement protein of tospoviruses is highly conserved (40-70% identity), with the exception of the first 60 N terminal amino acids, a domain that clearly diverged. For the G1 and G2 viral glycoproteins, blast searches revealed a significant homology between the C-terminally located tospoviral G1 (G(C)) protein with the counterpart of the animal-infecting bunyaviruses, suggesting a functional homology for these proteins.

Identification and characterization of a novel tospovirus species using a new RT-PCR approach.

A novel tospovirus serologically distinct from all established tospovirus species was found in Thailand in Physalis minima L. The S RNA of this virus was cloned by a new RT-PCR approach revealing a nucleotide sequence of 3257 nucleotides. The ambisense RNA segment encoded a nonstructural protein (NSs) of 469 amino acids, with a predicted Mr of 53.2 kDa, and a nucleoprotein (N) of 279 amino acids and a Mr of 31.0 kDa, so far the largest N protein known for any tospovirus species. N protein sequence comparisons revealed closet relationship to the species Watermelon bud necrosis virus (58% identity), Watermelon silver mottle virus and Peanut bud necrosis virus (57%) and a distant relationship to Peanut yellow spot virus (23%) and Peanut chlorotic fanspot virus (22%).

Diagnostic reproducibility of Pap testing in two regions of Mexico: the need for quality control mechanisms.

To assess the reproducibility of diagnostic results obtained by examining Pap smears for cervical neoplasia, a study was conducted using a single group of 20 Pap smears, 3 negative and 17 from patients with varying degrees of neoplasia. These smears were examined by 14 volunteer readers (13 cytotechnologists and 1 cytopathologist) from the Mexican states of Oaxaca and Veracruz, and also by a highly experienced cytopathologist certified by the Mexican Board of Pathological Anatomy whose work provided a reference standard. Individual variability, as assessed by the Kappa coefficient of concordance, showed considerable difference in the diagnostic results obtained by different readers-the degree of agreement depending on the type of cervical lesion involved and the number of specimens from patients with that type of lesion. There was little diagnostic agreement when the specimens were assessed for particular classes of cervical neoplasia-mild, moderate, or severe neoplasia, carcinoma in situ, or invasive cervical cancer. (The greatest concordance was found in diagnosing specimens from subjects with invasive cervical cancer.) However, when the diagnosis was assessed continuously, using Kappa weighted in accordance with the five possible diagnoses of cervical neoplasia, the apparent reproducibility of the diagnoses improved greatly, Kappa coefficients for the 14 readers ranging from 0.31 to 0.72. In general, these data support the view that there is a need in Mexico and other parts of the Americas to establish quality control mechanisms monitoring cytologic diagnosis of cervical neoplasia, to standardize diagnostic nomenclature using a system such as the Bethesda System, to institute periodic certification, and to provide continuing training. As this suggests, it is necessary not only to evaluate but also to bring about organizational changes in order to expeditiously prevent or correct the problems that currently constrain achievement of efficient and effective cytologic diagnosis.

O uso de veia do cordao umbilical humano como enxerto arterial. / The use of human umbilical cord for arterial graft

Os autores apresentam sua experiencia com o uso de enxerto de veia do cordao umbilical em 35 pacientes, em posicoes diversas, predominando as posicoes extra-anatomicas.Analisam a curva atuarial que mostra os resultados de 82,8% para as derivacoes axilo-axilares; 71,4% para derivacoes femoro-popliteas acima do joelho. Comentam os progressos conseguidos no processamento e nas tecnicas de implante; falam da nao ocorrencia, em seus pacientes, e na literatura, de aneurismas, calcificacoes, degeneracoes ou hiperplasia da intima; lembram a possibilidade do uso em derivacoes aorto-coronarias, em vias de acesso para hemodialise e derivacoes baixas nos membros inferiores por tolerarem flexoes; e lembram, tambem, a possibilidade do uso, com sucesso, do cateter de Fogarty gracas a firmeza da intima, a ausencia de valvulas e, tambem ao fato de pequenas lesoes da mesma nao ocasionarem tromboses