Theory of a Single Magnetic Impurity on a Thin Metal Film in Proximity to a Superconductor

We argue that the formation of Yu-Shiba-Rusinov excitations in proximitized thin films is largely mediated by a type of Andreev-bound state named after de Gennes and Saint James. This is shown by studying an experimentally motivated model and computing the overlap of the wave functions of these two subgap states. We find the overlap stays close to unity even as the system moves away from weak coupling across the parity-changing quantum phase transition. Based on this observation, we introduce a single-site model of the bound state coupled to a quantum spin. The adequacy of this description is assessed by reintroducing the coupling to the continuum as a weak perturbation and studying its scaling flow using Anderson's poor man's scaling.Comment: 12 pages, 3 figure

Partial Product Reduction based on Look-Up Tables

In this paper a new technique for partial product reduction based on the use of look-up tables for efficient processing is presented. We describe how to construct counter devices with pre-calculated data and their subsequent integration into the whole operation. The development of reduction trees organizations for this kind of devices uses the inherent integration benefits of computer memories and offers an alternative implementation to classic operation methods. Therefore, in our experiments we compare our implementation model with CMOS technology model in homogeneous terms

Effect of Dendritic Side Groups on the Mobility of Modified Poly(epichlorohydrin) Copolymers

[EN] The macromolecular dynamics of dendronized copolymer membranes (PECHs), obtained by chemical modification of poly(epichlorohydrin) with the dendron 3,4,5-tris[4-(n-dodecan-1-yloxy)benzyloxy] benzoate, was investigated. In response to a thermal treatment during membrane preparation, these copolymers show an ability to change their shape, achieve orientation, and slightly crystallize, which was also observed by CP-MAS NMR, XRD, and DSC. The phenomenon was deeply analyzed by dielectric thermal analysis. The dielectric spectra show the influence of several factors such as the number of dendritic side groups, the orientation, their self-assembling dendrons, and the molecular mobility. The dielectric spectra present a sub-Tg dielectric relaxation, labelled as gamma, associated with the mobility of the benzyloxy substituent of the dendritic group. This mobility is not related to the percentage of these lateral chains but is somewhat hindered by the orientation of the dendritic groups. Unlike other less complex polymers, the crystallization was dismantled before the appearance of the glass transition (alpha(Tg)). Only after that, clearing transition (alpha(Clear)) can be observed. The PECHs were flexible and offered a high free volume, despite presenting a high degree of modifications. However, the molecular mobility is not independent in each phase and the self-assembling dendrons can be eventually fine-tuned according to the percentage of grafted groups.This research was funded by the Spanish Ministry of Science, Innovation and Universities, grant POLYDECARBOCELL (ENE2017-86711-C3-1-R, ENE2017-86711-C3-3-R).Teruel Juanes, R.; Pascual-Jose, B.; Graf, R.; Reina, JA.; Giamberini, M.; Ribes-Greus, A. (2021). Effect of Dendritic Side Groups on the Mobility of Modified Poly(epichlorohydrin) Copolymers. Polymers. 13(12):1-19. https://doi.org/10.3390/polym13121961119131

Performance of Sulfonated Poly(Vinyl Alcohol)/Graphene Oxide Polyelectrolytes for Direct Methanol Fuel Cells

The use of nanotechnology along with the consideration of a functionalization and stabilization approach to poly(vinyl alcohol) (PVA) is considered useful for the preparation of cost-effective polyelectrolyte membranes. A set of nanocomposite and crosslinked membranes based on PVA/sulfosuccinic acid (SSA)/graphene oxide (GO) are prepared and analyzed as polyelectrolytes in direct methanol fuel cells (DMFCs). The crosslinking and sulfonation by the use of SSA enhances the stability and increase the proton-conducting sites in the PVA structure. The presence of GO augments the stability, remarkably decreases the methanol crossover, and enhances power density curves. An optimum value for proton conductivity is found for the 0.50 wt% of GO proportion, which decreases with higher concentrations of GO. Given the power density curve dependency on both the proton conductivity and the crossover reduction, the performance of these membranes as polyelectrolytes in DMFCs is strictly related to the balance between both factors. Therefore, a proportion of GO of 0.75 wt% may assure suitable proton conductivity of 3 mS cm−1 and high resistance to methanol permeability, reaching promising power density of 16 mW cm−2 with lower hydration levels

Resistance gene pool to co-trimoxazole in non-susceptible Nocardia strains

The soil-borne pathogen Nocardia sp. causes severe cutaneous, pulmonary, and central nervous system infections. Against them, co-trimoxazole (SXT) constitutes the mainstay of antimicrobial therapy. However, some Nocardia strains show resistance to SXT, but the underlying genetic basis is unknown. We investigated the presence of genetic resistance determinants and class 1-3 integrons in 76 SXT-resistant Nocardia strains by PCR and sequencing. By E test, these clinical strains showed SXT minimum inhibitory concentrations of ≥32:608 mg/L (ratio of 1:19 for trimethoprim: sulfamethoxazole). They belonged to 12 species, being the main representatives Nocardia farcinica (32%), followed by N. flavorosea (6.5%), N. nova (11.8%), N. carnea (10.5%), N. transvalensis (10.5%), and Nocardia sp. (6.5%). The prevalence of resistance genes in the SXT-resistant strains was as follows: sul1 and sul2 93.4 and 78.9%, respectively, dfrA(S1) 14.7%, blaTEM-1 and blaZ 2.6 and 2.6%, respectively, VIM-2 1.3%, aph(3')-IIIa 40.8%, ermA, ermB, mefA, and msrD 2.6, 77.6, 14.4, and 5.2%, respectively, and tet(O), tet(M), and tet(L) 48.6, 25.0, and 3.9%, respectively. Detected amino acid changes in GyrA were not related to fluoroquinolone resistance, but probably linked to species polymorphism. Class 1 and 3 integrons were found in 93.42 and 56.57% strains, respectively. Class 2 integrons and sul3 genes were not detected. Other mechanisms, different than dfrA(S1), dfrD, dfrF, dfrG, and dfrK, could explain the strong trimethoprim resistance shown by the other 64 strains. For first time, resistance determinants commonly found in clinically important bacteria were detected in Nocardia sp. sul1, sul2, erm(B), and tet(O) were the most prevalent in the SXT-resistant strains. The similarity in their resistome could be due to a common genetic platform, in which these determinants are co-transferred.This study was presented at the 54th Interscience Conference on Antimicrobial Agents and Chemotherapy, ICAAC2014, Washington, DC, USA. We thank Adrian Burton for editing and language assistance (http://physicalevidence.es/english/welcome). We are very grateful to all persons who took part in this study, and to the sample providers.S

Evaluación de la calidad seminal en pilotos de vuelos internacionales transoceánicos

Motivación: El factor masculino en reproducción está presente en la mitad de los casos de infertilidad, un problema de salud pública en auge en las ultimas décadas. Muchos estudios han demostrado que la calidad seminal se ha visto afectada por los contaminantes ambientales y los cambios en el estilo de vida, que pueden inducir procesos de fragmentación del DNA espermático o inducir estrés oxidativo(1). El objetivo de este trabajo consiste en evaluar la calidad seminal de un grupo concreto, los pilotos de vuelos transoceánicos que, por su profesión, pueden suponer un grupo de riesgo de problemas de fertilidad debido a sus condiciones laborales. Los cambios constantes de presión, temperatura y estación, pueden ocasionar daños a nivel celular con afectación del DNA, que implique procesos de fragmentación masiva y, consecuentemente, una disminución o pérdida de la fertilidad con el subsecuente fracaso en el embarazo. Este trabajo también pretende poner de manifiesto la necesidad de un seminograma avanzado, mas allá de los parámetros básicos analizados convencionalmente.Métodos:Se llevó a cabo un seminograma estándar para evaluar concentración, volumen, motilidad, morfología y vitalidad, con ayuda de sistemas informáticos (SCA) para los ensayos de concentración y motilidad, microscopía tanto de campo claro como de fluorescencia, así como el kit Vitaltest para el ensayo de vitalidad.Para el análisis de fragmentación de DNA se realizaron 2 ensayos: el SCD (Sperm Chromatin Dispersion) para evaluar la fragmentación total (2) y el ensayo COMET, el cual identifica específicamente las roturas de cadena doble(3). Ambos se realizaron mediante la utilización de kits comerciales (Halotech DNA) y microscopía de fluorescencia para su recuento.Asimismo se realizó un ensayo para medir el estrés oxidativo, también mediante el uso de un kit comercial para un análisis colorimétrico (Halotech DNA).Conclusiones: A pesar de no tener aún los resultados necesarios, hay muchos estudios que demuestran que la calidad seminal, sobre todo respecto al DNA, se ve afectada por múltiples factores, ya sean ambientales, genéticos o referentes al estilo de vida, por lo que cabe esperar que este grupo concreto se vea afectado negativamente debido a sus condiciones laborales. Cada vez van surgiendo mas casos en los que el DNA espermático está tan dañado, que el ovocito es incapaz de reparar ese daño, con lo que se justifica el uso de un seminograma avanzado que estudie el material genético

Endemic and epidemic Acinetobacter baumannii clones: a twelve-year study in a tertiary care hospital

BACKGROUND: Nosocomial outbreaks of multidrug-resistant Acinetobacter baumannii are of worldwide concern. Using pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), and multiple locus variable number tandem repeat sequence (VNTR) analysis (MLVA), the present work examines the genetic diversity of the endemic and epidemic A. baumannii clones isolated in a single hospital over a twelve-year period. RESULTS: PFGE analysis of 405 A. baumannii-calcoaceticus complex isolates detected 15 A. baumannii endemic/epidemic PFGE types (EE1 to EE15) that grouped into five clusters: EE1-EE8, EE9, EE10, EE11 and EE12-EE15. The MLST sequence type (ST) distributions were: international clone II (ST-2) 60%, international clone III (ST-3) 26.7%, ST-15 6.7%, and ST-80 6.7%. MLVA-8Orsay returned 17 allelic profiles. The large (L) VNTR marker profiles were fully concordant with the detected STs, and concordant with 14 up to 15 PFGE types. Imipenem resistance was detected in five PFGE types; the prevalence of the bla OXA-58-like and bla OXA-40-like genes was 60% and 40% respectively. CONCLUSIONS: PFGE proved to be a vital tool for analysis of the temporal and spatial distribution of the clones. MLST and the VNTR L-markers grouped the isolates into clonal clusters. The wide diversity of MLVA small (S)-markers, however, did not permit clustering. The present results demonstrate the persistence of several endemic PFGE types in the hospital, the involvement of some of them in outbreaks, and the inter hospital transmission of extensively drug-resistant ST-15 and ST-80.S

Identification and antimicrobial susceptibility of Streptomyces and other unusual Actinobacteria clinical isolates in Spain

Two hundred and eighty-six isolates from human clinical samples were identified between 1996 and 2019 as belonging to 8 families, 19 genera and 88 species of Actinobacteria. The most identified genera were Streptomyces (182 strains from 45 species), Actinomadura (29 strains, 5 species), Nocardiopsis (21 strains, 6 species) and Dietzia (18 strains, 5 species). The rest of the identified genera (15) contained 27 species with 36 isolates. Of the species studied, only 13/88 had been documented previously as isolates from clinical samples, and in some cases, as true pathogens. In this sense, a literature review of the species found in infections or in clinical samples without clear involvement in pathology has been carried out. Finally, the susceptibility to 8 antimicrobial agents has been studied. Streptomyces showed high resistance (80.8%) against cefotaxime and cotrimoxazole (55.5%), and no isolate resistance to amikacin and linezolid have been found. Lower percentages of resistance have been found in other genera, except in Dietzia (100% against cotrimoxazole and 44.4% against erythromycin). The greatest resistance in these genera was to cotrimoxazole (29.8) and erythromycin (27,9%), and no resistance to linezolid has been found in these genera. In Microbispora, Nonomuraea and Umezawaea, no resistant isolates have been found against any antibiotic studied. Only 3/104 isolates were resistant to amikacin in Amycolatopsis, Crossiella, and Micromonosopora. One isolate of Amycolatopsis was resistant to imipenem.S