Effects of intermixing and oxygen vacancies on a two-dimensional electron gas at the polar (TbScO\u3csub\u3e3\u3c/sub\u3e/KTaO) (001) interface

3d-5d perovskite oxides, ABO3 (where A and B are 3d or 5d elements), form polar surfaces in the (001)- stacked thin films. As a result, the polar-polar (001) interface between two ABO3 insulators could create polar discontinuity potentially producing a two-dimensional electron gas of higher density and stronger spatial localization compared to the widely studied polar-nonpolar oxide interfaces, such as (001) LaAlO3/SrTiO3. Here, as a model system, we explore the interface between polar (001) TbScO3 and polar (001) KTaO3 using first-principles density functional theory.We find that the intermixed interface Ta0.75Sc0.25O2/Tb0.75K0.25O maintaining the bulk perovskite charge stacking (e.g., . . . + 1/ − 1/ + 1 . . .) is insulating and has a lower energy than the metallic interface TbO/TaO2 breaking such stacking. This intermixed interface is, however, prone to the formation of oxygen vacancies which make it conducting. We emphasize that the driving force for the formation of the two-dimensional electron gas (2DEG) here is not a built-in electric field stemming from the polar discontinuity but the interface stoichiometry. We find that the ratio of oxygen vacancy concentration is a factor of 30 times larger at the interface than in bulk KTO at room temperature. The oxygen vacancy-induced 2DEG resides on the Ta-5d electronic orbitals with dxy and dxz/yz occupation dominating overall charge density near and far away from the interface

Interest rates volatility and its consequences on stock returns: The case study from Amman Stock Exchange, Jordan

Abstract. This paper examines the special effects of interest rates on the stock market return by using monthly time series data for the economy of Jordan over the period of 2006 to 2016. An extensive variety of econometric procedures have been involved to analyze the relationship between the interest rate and stock market return. The study exposes a constant and significant long-run relationship between the variables. By using Cointegration methods the experimental in the long run represents that a one percent rise in interest rate causes (12.3459 %)reduction in market index. The assessed error correction coefficient highlight that (-0.678522) percent deviation of stock returns are corrected in the short run. Impulse response function of the study furthermore sustains the positive relationship between the variables. The result of Variance decompositions recommends that about (99.99705%) of the variation in stock market returns is referring to its own shock which denotes that stock market returns are mostly independent of the other variables in the structure. To go over the main points, Granger causality analysis yield that there is no presence of a unidirectional causality as of interest rate to the market index.Keywords. Stock market, Cointegration, Granger causality, Interest rate, ASE.JEL. E40, E43, G12

Reseña histórica del Instituto de Jovellanos de Gijón

Copia digital : Biblioteca de Asturias "Ramón Pérez de Ayala" : Biblioteca Pública Estatal de Oviedo, 201

15N tracing to elucidate links between biodiversity and nitrogen cycling in a grassland experiment

Nitrogen (N) cycling is a fundamental ecosystem function of high complexity because N undergoes many transformations in soil and vegetation. The effect of biodiversity loss on ecosystem functions in general, and on N cycling in particular, was studied in several manipulative field experiments. To generate a comprehensive view of the influence of species richness on all major N transformations, we conducted laboratory incubations, in which we added 15N-labeled ammonium and nitrate to soil samples of the “Jena Experiment”, a manipulative large scale, long-term biodiversity experiment in grassland. The experimental site is located in Jena, Germany. The design consists of 4 blocks and 82 plots with 1-60 species and 1-4 functional groups (grasses, legumes, small herbs, tall herbs). Approx. 400 g of field-fresh soil was sampled from each plot of one of the 4 blocks and divided into three aliquots of 100 g each. In order to trace N turnover, we amended the incubations (in triplicate) either with 15N-labelled (98 at%) ammonium, nitrate, or with a mixture of both. The samples were incubated for two months at 20°C. Soil solution was extracted 1, 2, 4, 9 and 16 days after 15N application by percolating 100 mL of nutrient solution through each vessel. Concentrations of NH4-N, NO3-N and total N in the extracts were determined with colorimetric methods. The N-isotopic composition in nitrate was analyzed by isotope ratio mass spectrometry (IRMS) using the denitrifier method. Ammonium N isotope ratios were determined using the “hypobromite oxidation” method, in which ammonium-N is converted to nitrite followed by azide reaction to nitrous oxide and IRMS analysis. The results will be comprehensively evaluated in a quantitative context using the modelling approach of Müller et al. (2007) to determine the size of six N pools and the rates of nine N transformations. Links between N transformation rates, N-pool size and plant species richness will be verified with the help of ANOVA

Magnetic coiffure: Engineering of human hair surfaces with polyelectrolyte-stabilised magnetite nanoparticles

Here we report a spontaneous electrostatic coating of human hair with aqueous Fe3O4 colloids capable to tailor magnetic properties to hair, orienting and even moving them under the influence of the external magnetic field. Magnetite particles were modified by cationic and anionic polyelectrolytes and then successfully deposited in dense arrays, starting from cuticle gaps and spreading further over a major hair surface. These biocompatible and biodegradable magnetic nanoparticles may serve as carriers for drug loading and delivery for topical pharmaceutical treatments. The deposition process was imaged in real-time using dark-field microscopy. The hair specimens were further studied using a number of characterisation techniques. Under application of an external magnetic field, the nanoparticle magnetic ordering was obtained resulting in the hair alignment and attraction along the field applied. We believe the technology reported here will find a range of applications in topical drug delivery and hair care

Organoid systems to study the human female reproductive tract and pregnancy

Funder: Centre for Trophoblast Research L'Oreal Women in Science FellowshipAbstract: Both the proper functioning of the female reproductive tract (FRT) and normal placental development are essential for women’s health, wellbeing, and pregnancy outcome. The study of the FRT in humans has been challenging due to limitations in the in vitro and in vivo tools available. Recent developments in 3D organoid technology that model the different regions of the FRT include organoids of the ovaries, fallopian tubes, endometrium and cervix, as well as placental trophoblast. These models are opening up new avenues to investigate the normal biology and pathology of the FRT. In this review, we discuss the advances, potential, and limitations of organoid cultures of the human FRT

Organoid systems to study the human female reproductive tract and pregnancy

Funder: Centre for Trophoblast Research L'Oreal Women in Science FellowshipAbstract: Both the proper functioning of the female reproductive tract (FRT) and normal placental development are essential for women’s health, wellbeing, and pregnancy outcome. The study of the FRT in humans has been challenging due to limitations in the in vitro and in vivo tools available. Recent developments in 3D organoid technology that model the different regions of the FRT include organoids of the ovaries, fallopian tubes, endometrium and cervix, as well as placental trophoblast. These models are opening up new avenues to investigate the normal biology and pathology of the FRT. In this review, we discuss the advances, potential, and limitations of organoid cultures of the human FRT

Identification of Novel Interactors of SEC6 via Genetic Suppressor Screen Using a Saccharomyces cerevisiae Genomic DNA Library

Polarized protein secretion is a fundamental process for all organisms, from yeast to higher eukaryotes. The secretory pathway in eukaryotes includes many steps mediated by hundreds of essential proteins. Our interest lies on Sec6, which is an 88kDa protein subunit of the tethering complex named exocyst, which is known to play diverse roles in recognition, tethering, and SNARE-mediated fusion of secretory vesicles. Previous work on Sec6 done by Munson and Songer (2009) explored phenotypes of two novel SEC6 mutant proteins, whose conserved surface amino acids had been altered. Both sec6-49 and sec6-54 mutant alleles displayed severe temperature sensitive growth and secretion defects. Interestingly, at non-permissive conditions trafficking of secretory vesicles to the plasma membrane was unimpaired, but none of the exocyst subunits were correctly polarized at sites of secretion. Biochemical analyses examining the state of exocyst assembly in both mutant backgrounds showed that the complex is intact at non-permissive conditions. We hypothesize that Sec6 has an important anchoring function for the exocyst, and that mislocalization of exocyst stems from compromising Sec6’s interaction with an unknown factor(s). Our research aims to identify and validate novel interactors of Sec6 that are critical for anchoring the exocyst complex at the plasma membrane. We utilized a classic genetic high copy suppressor screen to identify genes that suppress the temperature sensitive (ts) phenotype of sec6-49 cells upon overexpression. The plasmids from cells that survived temperature shift after transformation were purified, and genomic inserts were confirmed via restriction digests. Currently, sequencing via primers flanking the genomic insert has been initiated to identify the location of the genomic inserts and candidate genes. Overall, the isolation and characterization of novel interactors will shed light on mechanistic details of Sec6 function, which is critical for understanding mechanistic details of quality control in the secretory pathway

Classification of protein interaction sentences via gaussian processes

The increase in the availability of protein interaction studies in textual format coupled with the demand for easier access to the key results has lead to a need for text mining solutions. In the text processing pipeline, classification is a key step for extraction of small sections of relevant text. Consequently, for the task of locating protein-protein interaction sentences, we examine the use of a classifier which has rarely been applied to text, the Gaussian processes (GPs). GPs are a non-parametric probabilistic analogue to the more popular support vector machines (SVMs). We find that GPs outperform the SVM and na\"ive Bayes classifiers on binary sentence data, whilst showing equivalent performance on abstract and multiclass sentence corpora. In addition, the lack of the margin parameter, which requires costly tuning, along with the principled multiclass extensions enabled by the probabilistic framework make GPs an appealing alternative worth of further adoption