Tailoring palladium nanocontacts by electromigration

Electromigration is employed in nanoelectronics for transforming narrow metallic wires into electrodes separated by a few nanometers gap. In this work, we fabricate either nanoconstrictions or nanogap electrodes by performing electromigration in palladium nanowires. The device resistance and the cross section of the initial nanowires allow us to regulate the conditions for transforming deterministically each nanowire in a specific final device. The resulting samples show unique electrical transport characteristics and could be used in multiple nanoelectronics research applications, from ballistic transport to electrodes for single molecular devices.Fil: Arzubiaga, Libe. CIC nanoGUNE; EspañaFil: Golmar, Federico. Instituto Nacional de Tecnología Industrial; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Llopis, Roger. CIC nanoGUNE; EspañaFil: Casanova, Félix. CIC nanoGUNE; España. Basque Foundation for Science; EspañaFil: Hueso, Luis E.. CIC nanoGUNE; España. Basque Foundation for Science; Españ

Room-temperature air-stable spin transport in bathocuproine-based spin valves

Organic semiconductors, characterized by weak spin-scattering mechanisms, are attractive materials for those spintronic applications in which the spin information needs to be retained for long times. Prototypical spin-valve devices employing organic interlayers sandwiched between ferromagnetic materials possess a figure of merit (magnetoresistance (MR)) comparable to their fully inorganic counterparts. However, these results are a matter of debate as the conductivity of the devices does not show the expected temperature dependence. Here we show spin valves with an interlayer of bathocuproine in which the transport takes place unambiguously through the organic layer and where the electron spin coherence is maintained over large distances (>60 nm) at room temperature. Additionally, the devices show excellent air stability, with MR values almost unaltered after 70 days of storage under ambient conditions, making bathocuproine an interesting material for future spintronic applications.Fil: Sun, Xiangnan. CIC nanoGUNE; EspañaFil: Gobbi, Marco. Université de Strasbourg; Francia. CIC nanoGUNE; EspañaFil: Bedoya Pinto, Amilcar. CIC nanoGUNE; EspañaFil: Txoperena, Oihana. CIC nanoGUNE; EspañaFil: Golmar, Federico. CIC nanoGUNE; España. Instituto Nacional de Tecnología Industrial; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Llopis, Roger. CIC nanoGUNE; EspañaFil: Chuvilin, Andrey. CIC nanoGUNE; España. Fundación Vasca para la Ciencia; EspañaFil: Casanova, Félix. CIC nanoGUNE; España. Fundación Vasca para la Ciencia; EspañaFil: Hueso, Luis E.. CIC nanoGUNE; España. Fundación Vasca para la Ciencia; Españ

Composition and antimicrobial activity of the essential oil of Clinopodium ascendens (Jordan) Sampaio from Madeira

Clinopodium ascendens (Jordan) Sampaio [synonyms = Calamintha ascendens Jordan = C. officinalis Moench ssp. ascendens (Jord.) Mateo = C. sylvatica Bromf. ssp. ascendens (Jord.) P.W. Ball] is a small herbaceous plant with a very strong and distinctive mint aroma. The plant is known for its medical uses in folk medicine and as a spice in Italian kitchens. In Madeira Island, Clinopodium ascendens, known locally as ‘neveda’, grows wild along the shady paths of the Laurissilva forest. The local population uses the leaves of calamint as a mouth freshener and to alleviate headache and toothache. The essential oil obtained by hydrodistillation of the aerial parts of C. ascendens growing wild in Madeira was analysed by a combination of CC, GC, GC–MS, 1 H- and 13C-NMR. The oil was dominated by C3 oxy genated p-menthane derivatives: cis-isopulegone (75.2%), pulegone (6.9%), neoiso-isopulegol (6.0%) and trans-isopulegone (4.5%). The whole essential oil was tested against a variety of bacteria, both Gram-positive and Gram-negative, and two fungi; it exhibited remarkable activity against Escherichia coli and was active against Agrobacterium tumefasciens and Staphylococcus aureus and the phytopathogenic fungus Botrytis cinerea. It was ineffective against Streptococcus faecium, Streptococcus mutans and Candida albicans.info:eu-repo/semantics/publishedVersio

Direct identification and quantitative determination of costunolide and dehydrocostuslactone in the fixed oil of Laurus novocanariensis by13C-NMR spectroscopy

The fixed oil of Laurus novocanariensis (previously L. azorica) contains mostly glycerides together with minor non-saponifiable compounds. The direct identification and quantitative determination of costunolide and dehydrocostuslactone, two sesquiterpene lactones components of the oil that exhibit biological activities, is described. The analysis was carried out using 13C-NMR spectroscopy (signal acquisition with inverse gated decoupling of protons; diglyme as internal standard) without separation, derivatisation or any sample preparation.info:eu-repo/semantics/publishedVersio

Incidence and Characterization of Patients with Atypical Squamous Cells of Undetermined Significance

Foundation: cytological study in the most important of the programs for early detection of cervical uterus cancer. The most frequently atypia found was squamous cells of undetermined significance. Objective: to determine the incidence of squamous cells of undetermined significance in the consultation of Cervix Pathology at the Gyneco-Obstetric University Hospital Mariana Grajales. Method: it was a cross-sectional study in a universe constituted by the 206 patients referred to the cervix pathology consultation during the year 2011. The sample was 120 women from the organic cytology registration book at the pathological anatomy department of the Hospital, who had all the required data with a report of atypical squamous cells of undetermined significance. The studied variables were: age in years completed at the time of diagnosis, age in years of the first sexual relations and the number of births. A data file was created in Excel where the necessary calculations were made. Absolute numbers and percentages were used to summarize the qualitative and average variables, standard deviation, minimum and maximum values for the quantitative variables. Results: an incidence of atypical squamous cells of undetermined significance of 0.37 % was obtained, it predominated in women older than 40 and younger than 50 years old and most of them started their sexual relations before the age of 20 and had 2 children. Conclusion: the report incidence of atypical squamous cells during the studied period of time was low; it predominated in middle-aged women, in those who had an early sexual relation and in multiparous women

Probing low-energy hyperbolic polaritons in van der Waals crystals with an electron microscope

Van der Waals materials exhibit intriguing structural, electronic, and photonic properties. Electron energy loss spectroscopy within scanning transmission electron microscopy allows for nanoscale mapping of such properties. However, its detection is typically limited to energy losses in the eV range-too large for probing low-energy excitations such as phonons or mid-infrared plasmons. Here, we adapt a conventional instrument to probe energy loss down to 100 meV, and map phononic states in hexagonal boron nitride, a representative van der Waals material. The boron nitride spectra depend on the flake thickness and on the distance of the electron beam to the flake edges. To explain these observations, we developed a classical response theory that describes the interaction of fast electrons with (anisotropic) van der Waals slabs, revealing that the electron energy loss is dominated by excitation of hyperbolic phonon polaritons, and not of bulk phonons as often reported. Thus, our work is of fundamental importance for interpreting future low-energy loss spectra of van der Waals materials.We acknowledge financial support from the European Commission under the Graphene Flagship (GrapheneCore1, grant no. 696656), the ERC starting grant SPINTROS (grant no. 257654), and the Spanish Ministry of Economy and Competitiveness (National plans MAT2014-53432-C5-4-R, MAT2015-65159-R, MAT2015-65525-R, and FIS2016-80174-P). A.K. also thanks for the Czechoslovak Microscopic Society/FEI scholarship.Peer Reviewe

Covid-19: uso y abuso de internet y teléfono móvil en estudiantes universitarios.

The COVID-19 pandemic has caused a change in the life habits of the general population. In the last year, technology has constituted an effective resource for the student, at an academic, social and family level. However, despite the usefulness of new technologies, inappropriate or abusive use can lead to negative consequences in the student’s family, social and academic life. The objective of this work is to analyze the effects that the pandemic caused by COVID-19 has produced on the habits of young university students; use of new technologies, daily time dedicated to the use of the internet and mobile phone, as well as the possible problematic use of them. The simple consisted of 671 university students with different degrees from the University of Jaen. The questionnaire by Oliva et al., (2012) on the habit of using new technologies. The questions refer to the age of onset, level of use, daily time of use before and after COVID-19, type of activities that they habitually carry out on the internet and the problematic use of the internet and mobile phone in the academic, social and family. The results indicate that COVID-19 has caused an increase in the number of hours dedicated to using the internet and mobile phone. The activities for which they use the internet most frequently are academic work, email and social networks, chats or forums. Finally, among those who indicate abusive use of the internet and mobile phone, they indicated having academic, social and family problems. We can conclude that, although there is an increase in the use of new technologies as a result of COVID-19, their use in university students is mainly intended for academic training, although it is also causing some problems in different areas of life of the students.La pandemia provocada por el COVID-19 ha provocado un cambio en los hábitos de vida de la población en general. En el último año, la tecnología ha constituido para el estudiante un recurso eficaz, no solo a nivel académico sino también social y familiar. Sin embargo, a pesar de la utilidad de las nuevas tecnologías, un uso inadecuado o abusivo puede producir consecuencias negativas en la vida familiar, social y académica del estudiante. El objetivo de este trabajo consiste en analizar los efectos que ha producido la pandemia provocada por el COVID-19 en los hábitos de jóvenes universitarios; uso de las nuevas tecnologías, tiempo diario dedicado al uso de internet y teléfono móvil, así como en el posible uso problemático de los mismos. La muestra estaba compuesta por 671 estudiantes universitarios de diferentes titulaciones de la Universidad de Jaén. Se utilizó una adaptación del cuestionario de Oliva et al. (2012) sobre el hábito de uso de las nuevas tecnologías. Las cuestiones hacen referencia a la edad de inicio, nivel de uso, tiempo diario de uso antes y después del COVID-19, tipo de actividades que realizan habitualmente en internet y el uso problemático de internet y el teléfono móvil en el ámbito académico, social y familiar. Los resultados indican que la COVID-19 ha provocado un incremento en el número de horas dedicadas al uso de internet y teléfono móvil. Las actividades para las que utilizan internet con más frecuencia son la realización de trabajos académicos, correo electrónico y redes sociales, chats o foros. Finalmente, aquellos que indican hacer un uso abusivo de internet y teléfono móvil, señalaban tener problemas académicos, sociales y familiares. Podemos concluir que, aunque se produce un aumento en el uso de las nuevas tecnologías como consecuencia del COVID-19, su uso, en estudiantes universitarios se destina mayormente a la formación académica, aunque también está provocando algunos problemas en los diferentes ámbitos de la vida de los estudiantes