Bright, balanced white‐light electroluminescence has been achieved from a single active oligothiophene compound. White light is created by the superposition of a broad blue–green‐light emission ...originating from the single molecule and a red‐shifted narrow peak due to dimer formation. These results open the way to the fabrication of novel, low‐cost white‐light‐emitting devices with a single molecular material as the active compound.
Abstract Human cystic echinococcosis is a highly endemic zoonotic disease in the province of Neuquén, Patagonia Argentina, although a hydatid control programme has been carried out since 1970. Human ...infection due to Echinococcus canadensis (G6 genotype) is frequent in Neuquén. However, the reservoir for this species remains undetermined in a region where camels are absent. We investigated the fertility, viability and molecular epidemiology of hydatid cysts obtained from local goats, pigs and sheep in order to identify the possible reservoirs of E. canadensis (G6). We also analyzed isolates from infected dogs. A total of 67 isolates were identified by the DNA sequencing of the mitochondrial cytochrome c oxidase subunit 1 gene. Cysts from sheep ( n = 16), goats ( n = 23) and pigs ( n = 18) and adult worms from 10 infected dogs were analyzed. The fertility of the hydatid cysts was 78.6%; 90.4% and 94.4% for sheep, goats and pigs, respectively. We detected E. canadensis (G6) in 21 of 23 goat samples and in 1 dog isolate, E. canadensis (G7) in all the pig isolates, E. granulosus sensu stricto (G3) in 1 sheep and the G1 genotype in 15 sheep, 2 goats and 9 dog samples. The G1 haplotypes included the common sheep strain sequence and 2 microvariants of this sequence. E. granulosus sensu stricto (G3) is described for the first time in South America. We conclude that goats act as reservoir for E. canadensis (G6) in Neuquén, and that control strategies may have to be adapted to local molecular epidemiology to improve the control of parasite transmission.
Shiga toxin‐producing Escherichia coli (STEC) O157:H7 is a worldwide concern. Cattle are their main reservoir and may contaminate watercourses through manure. We characterized a collection of 38 STEC ...O157:H7 strains isolated from surface water in feedlots areas (puddles inside pens formed after the rainfall or by spill around drinking troughs, and small water courses and lagoons, formed by runoff). Nineteen (50·0%) strains harboured stx2a/stx2c genes, 18 (47·4%) stx2c and one stx1a/stx2c. All strains harboured eae, ehxA, rfbO157 and fliCH7 genes, and the putative virulence determinants ECSP_0242, ECSP_2687 and ECSP_3620. All isolates tested as Lineage I/II by lineage‐specific polymorphism assay‐6. Nineteen (50%) belonged to the high virulent clade 8. The q21 allele was found in all strains and q933/q21 alleles in 17 (44·7%). By XbaI‐pulsed‐field gel electrophoresis, 29 strains were grouped into seven clusters. Four clusters grouped isolates from distant places separated by 150–250 km. This may be related to vectors, like birds, involved in their spread. Otherwise, three clusters contained isolates recovered at same places with intervals of 1–9 months. This could be explained by the high environmental persistence of STEC O157:H7. These strains recovered from surface water showed similar genotypes to those found in the bovine reservoir and in human diseases, and could be linked to the high incidence of haemolytic uremic syndrome in Argentina.
Significance and Impact of the Study
The challenge for the growing global demand for food is to find sustained production strategies without collateral effects. Intensive livestock operations generate large volumes of manure that can contaminate a finite resource, the water. This study shows how water contaminated by confined feeding operations can transport dangerous pathogens and warns to pay more attention to control and sanitation systems to prevent this type of pollution.
Significance and Impact of the Study: The challenge for the growing global demand for food is to find sustained production strategies without collateral effects. Intensive livestock operations generate large volumes of manure that can contaminate a finite resource, the water. This study shows how water contaminated by confined feeding operations can transport dangerous pathogens and warns to pay more attention to control and sanitation systems to prevent this type of pollution.
In this paper we deepen the study of a thermodynamical model, based on the extended irreversible thermodynamics with internal variables, for a semiconductor doped by impurities of n type, where we ...take into consideration the density of holes coming from the intrinsic base of the semiconductor and its flux. Furthermore, taking into account a geometric model developed for n and p type semiconductors in a previous paper, we derive, in the same geometrized framework, the dynamical system on the fibre bundle of the processes for
simple material elements of anisotropic n-type semiconductors, the transformation induced by the process, the entropy function and the entropy 1-form. The derivation of the entropy 1-form is the starting point to introduce an extended thermodynamical phase space. Then, we exploit Clausius–Duhem inequality for this medium and using Maugin’s technique we work out the laws of state, the extra entropy flux, the residual dissipation inequality and the heat equation in the first and the second form.
► The deepened study of a thermodynamical model for n-type semiconductors, in the framework of extended non-equilibrium thermodynamics. ► The achievement of linearized constitutive equations for the materials under considerations. ► The development, within thermodynamics of simple materials, of a geometrical model for extrinsic semiconductors, with the derivation of a dynamical system and an entropy 1-form. ► The investigation of a residual dissipation inequality and the heat equation in a first and second form for n-type semiconductors.
BACKGROUNDSeborrheic keratoses (SK) are easily recognizable by clinical and dermoscopic approach, nevertheless, some lesions act as a simulator of different skin conditions lacking typical clinical ...and dermoscopic criteria. OBJECTIVEThe aim of our study was to find specific dermoscopic features or a global pattern to improve diagnostic skills for challenging SK. MATERIALS AND METHODSWe examined 72 atypical SK excised from September 2014 up to September 2017 by using the 2-step algorithm modified by Malvehy (2002) and Argenziano (2003). RESULTSIn our study population, an average of 4.04 out of 15 dermoscopic specific criteria for SK was found (for example, multiple milia-like cysts). Additional criteria not included in 2-step algorithm were blue-whitish veil (found in 3 SK; 4.2%), polymorphous vessels (18 SK; 25%), blotch/globules (6 SK; 8.3%), shiny white streaks (3 lesions; 4.2%). The most represented global patterns were reticular (27 SK; 37.5%) and not specific (15 SK; 20.8%). All lesions exhibited peculiar findings of SK, furthermore elements suggestive for melanocytic lesion were found in 79.2% of all lesions. Comparing the literature and our results, we found 3 significant differences: a) the less prevalence of SK specific criteria in our study population; b) the description of findings usually not related to SK, among which blue-whitish veil, polymorphous vessels, blotch/globules and shiny white streaks, and c) 2 patterns not previously defined represented by "not specific pattern" (20.9% of all lesions examined) and "vascular pattern" (12.5% of all lesions examined) were also described. No specific feature or global pattern, statistically significant for dermoscopic diagnosis of difficult-to-diagnose SK have been found. CONCLUSIONNevertheless the useful findings, no specific feature or global pattern statistically significant for dermoscopic diagnosis of challenging SK have been found. According to the 2-step algorithm and the dermatoscopic scoring system for melanocytic and not melanocytic lesion, SK with one or more dermatoscopic findings typical of melanocytic lesion should be removed surgically to exclude classic melanoma or melanoma mimicking SK.
Abstract Shiga toxin-producing Escherichia coli (STEC) are important food-borne pathogens associated with human diseases. In Argentina, O157:H7 is the dominant serotype in hemolytic uremic syndrome ...(HUS) cases. Previously, we have described the almost exclusive circulation of human E. coli O157 strains belonging to the hypervirulent clade 8 in Neuquén Province. The aim of the present study was to investigate, by a broad molecular characterization, if this particular distribution of E. coli O157 clades in Neuquén is similar to the situation in other regions of the country and if it may be originated in a similar profile in cattle, its main reservoir. Two-hundred and eighty O157 strains (54 bovine and 226 human) isolated between 2006 and 2008 in different regions of Argentina were studied. All strains harbored rfbO157 , fliCH7 , eae , and ehxA genes. The predominant genotype was stx 2 a / stx 2 c in human (76.1%) and bovine (55.5%) strains. All human isolates tested by Lineage-Specific Polymorphism Assay (LSPA-6), were lineage I/II; among bovine strains, 94.1% belonged to lineage I/II and 5.9% to lineage I. No LSPA-6 lineage II isolates were detected. Single nucleotide polymorphism (SNP) analysis has revealed the existence of nine clade phylogenetic groups. In our clinical strains collection, 87.6% belonged to the hypervirulent clade 8, and 12.4% were classified as clade 4/5. In bovine isolates, 59.3% strains were clade 8, 33.3% clade 4/5 and 7.4% clade 3. More than 80% of human strains showed the presence of 6 of the 7 virulence determinants described in the TW14359 O157 strain associated with the raw spinach outbreak in the U.S. in 2006. More than 80% of bovine strains showed the presence of 3 of these factors. The q933 allele, which has been related to high toxin production, was present in 98.2% of clinical strains and 75.9% of the bovine isolates. The molecular characterization of human STEC O157 strains allows us to conclude that the particular situation previously described for Neuquén Province, may actually be a characteristic of the whole country. These genetic features are quite similar to those observed in the bovine reservoir and may be derived from it. This data confirms that, unlike the rest of the world, in Argentina most of the STEC O157 strains present in cattle may cause human infections of varying severity and the marked virulence described for these strains may be related to the high incidence of HUS in our country.
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