366 research outputs found
Interactions and thermoelectric effects in a parallel-coupled double quantum dot
We investigate the nonequilibrium transport properties of a double quantum
dot system connected in parallel to two leads, including intradot
electron-electron interaction. In the absence of interactions the system
supports a bound state in the continuum. This state is revealed as a Fano
antiresonance in the transmission when the energy levels of the dots are
detuned. Using the Keldysh nonequilibrium Green's function formalism, we find
that the occurrence of the Fano antiresonance survives in the presence of
Coulomb repulsion. We give precise predictions for the experimental detection
of bound states in the continuum. First, we calculate the differential
conductance as a function of the applied voltage and the dot level detuning and
find that crossing points in the diamond structure are revealed as minima due
to the transmission antiresonances. Second, we determine the thermoelectric
current in response to an applied temperature bias. In the linear regime,
quantum interference gives rise to sharp peaks in the thermoelectric
conductance. Remarkably, we find interaction induced strong current
nonlinearities for large thermal gradients that may lead to several nontrivial
zeros in the thermocurrent. The latter property is especially attractive for
thermoelectric applications.Comment: 9 pages, 8 figure
Progressive tauopathy in P301S tau transgenic mice is associated with a functional deficit of the olfactory system.
Multiple neurodegenerative disorders with tau pathology are characterised by the loss of memory and cognitive decline that can be associated with other symptoms including olfactory alterations that are often regarded as an early symptom of the diseases. Here, we have investigated whether olfactory dysfunction is present in the P301S human tau transgenic mice and if it is associated to tau pathology. Progressive tauopathy and neurodegeneration were noticeable in the olfactory bulb and piriform cortex at early age in the P301S human tau transgenic mice and olfactory sensitivity for social or non-social odours was significantly impaired at 3 months of age, when the piriform cortex-dependent odour-cross habituation was also disrupted. The olfactory alterations in the P301S tau transgenic mouse line provide an in vivo system where to test the mechanism-based therapies for the common and yet untreatable tauopathies.This work was supported by the European Union Framework 7 Project Plasticise (S.Y., M.G.S.) and the Alzheimerâs Research UK (M.G.S.).This is the author accepted manuscript. The final version is available from Wiley via http://dx.doi.org/10.1111/ejn.13333
Collaborative learning supported by rubrics improves critical thinking
In previous works we developed and assessed a teaching program, ARDESOS v.1, with which we aimed to improve the fundamental skills of Critical Thinking. The results obtained were positive, but modest. After analyzing the limitations of the program we introduced certain modifications and assessed the new version. The changes involved designing the activities programmed by means of rubrics and making the students perform them with less direct orientation from the instructor. In sum specificity and initiative proved to be the key variables in the improved program, ARDESOS v.2. The data collected pointed to a significant improvement of the new version over the old one in the following aspects: a) version 2 improved all the fundamental dimensions, mainly in the pre- and post-test measurements, to a significant extent (Studentâs t test); b) the effect size (Cohenâs d) was significantly higher, and finally c) these improvements in the program elicited better performance. Accordingly, an improvement in Critical Thinking can be achieved via an instruction design that attends to the factors that really induce change. Currently, these results have allowed us to successfully add a new improvement to the instruction, which we havere-evaluated
A nocturnal atmospheric loss of CH2I2 in the remote marine boundary layer
This is the final version of the article. It was first available from Springer via http://dx.doi.org/10.1007/s10874-015-9320-6Ocean emissions of inorganic and organic iodine compounds drive the biogeochemical cycle of iodine and produce reactive ozone-destroying iodine radicals that influence the oxidizing capacity of the atmosphere. Di-iodomethane (CH?I?) and chloro-iodomethane (CH?ICl) are the two most important organic iodine precursors in the marine boundary layer. Ship-borne measurements made during the TORERO (Tropical Ocean tRoposphere Exchange of Reactive halogens and Oxygenated VOC) field campaign in the east tropical Pacific Ocean in January/February 2012 revealed strong diurnal cycles of CH?I? and CH?ICl in air and of CH?I? in seawater. Both compounds are known to undergo rapid photolysis during the day, but models assume no night-time atmospheric losses. Surprisingly, the diurnal cycle of CH?I? was lower in amplitude than that of CH?ICl, despite its faster photolysis rate. We speculate that night-time loss of CH?I? occurs due to reaction with NO? radicals. Indirect results from a laboratory study under ambient atmospheric boundary layer conditions indicate a k_(CH?I?+NO?) of ?4 ? 10??? cm? molecule?? s??; a previous kinetic study carried out at ?100 Torr found k_(CH?I?+NO?) of 4 ? 10??? cm? molecule?? s??. Using the 1-dimensional atmospheric THAMO model driven by sea-air fluxes calculated from the seawater and air measurements (averaging 1.8 +/? 0.8 nmol m?? d?? for CH?I? and 3.7 +/? 0.8 nmol m?? d?? for CH?ICl), we show that the model overestimates night-time CH?I? by >60 % but reaches good agreement with the measurements when the CH?I?+ NO? reaction is included at 2?4 ? 10??? cm? molecule?? s??. We conclude that the reaction has a significant effect on CH?I? and helps reconcile observed and modeled concentrations. We recommend further direct measurements of this reaction under atmospheric conditions, including of product branching ratios.LJC acknowledges NERC (NE/J00619X/1) and the National Centre for Atmospheric Science (NCAS) for funding. The laboratory work was supported by the NERC React-SCI (NE/K005448/1) and RONOCO (NE/F005466/1) grants
Diffusion-Weighted Magnetic Resonance Imaging in Peritoneal Carcinomatosis from Ovarian Cancer: Diagnostic performance in correlation with surgical findings.
Purpose
Ovarian cancer (OC) is the commonest cause of death by gynaecological cancer in developed countries.
Peritoneal carcinomatosis (PC) complete debulking without residual disease of >1âcm is the best prognostic predictor in advanced OC.
PC is assessed with Computed tomography (CT). CT accuracy and cytoreduction success predictive ability are limited. PET/CT is not an imaging standard for PC.
PC shows high signal foci in Diffusion-weighted magnetic resonance imaging (DWI MRI).
We assessed the diagnostic performance (DP) and tumour burden correlation of Whole body DWI with background suppression MRI (WB-DWIBS/MRI) in PC of suspected OC using the Peritoneal Cancer Index (PCI), referring to cytoreduction surgery as the standard reference.
Method
Fifty patients with suspicion of disseminated OC underwent cytoreduction and WB-DWIBS/MRI. The PCI scores tumour burden (0â3) in 13 anatomical regions (global range of 0â39). Two radiologists (Rad1/Rad2) assessed the PCI preoperatively and with surgical findings.
We evaluated regional and global DP, the interobserver agreement (CohenÂŽs kappa coefficient), statistical differences (McNemar test) and tumour burden (Pearsonâs test).
Results
72% (36/50) were epithelial OC and 78% (39/50) achieved complete cytoreduction. Global-PCI correlation was 0.762 (Rad1) with DP: Sensitivity 0.84, specificity 0.89, accuracy 0.89, and kappa 0.41.
Average global-PCI was 7. The pelvis and right hypochondrium showed the highest positive rate and DP, while the intestinal regions presented the lowest. Previous studies reported higher sensitivity than CT or PET/CT, although only a few used the PCI.
Conclusions
WB-DWIBS/MRI is reliable to depict, quantify and to predict complete cytoreductive surgery in OC PC.pre-print2737 K
Tridimensional-Temporal-Thematic Hydroclimate Modeling of Distributed Parameters for the San Miguel River Basin
A geographic database (GDB) for the San Miguel river basin has been built by integrating data from multiple sources for analysis and graphical representation of diverse physiographic features and hydroclimate phenomena such as rainfall, temperature, soil-evaporation and topography, among others. This database allowed us to combine digital maps and images along with thematic information and spatially- referenced vector data. Moreover, further geographical referencing and validating processes enabled us to accurately represent continuous data through discrete data structures which fit the mathematical models used in representing the physical phenomena at the study site. In this paper we discuss some significant progress on models generated for the analysis of existing records for a season with measurable rainfall at the San Miguel river basin during the period from June 1st to September 30th of 2005
Manganese oxides as biominerals in a granitic subterranean environment
Black coatings were detected on granite surfaces in groundwater catch work tunnels from Porto city (NW Portugal). XRD, FTIR, Micro-Raman, ICP-MS, TEM-EDS, SEM-EDS and SEM-FIB were the analytical procedures carried out to investigate the origin of the black coatings. In this subterranean environment, the enrichment in metals and other trace elements, such as Mn and Fe, and clay minerals characterize the black microbial mats, mainly composed of Mn/Fe-oxidising bacteria.Fundação para a CiĂȘncia e a Tecnologia (FCT
Evolution of Angiogenic Factors in Pregnant Patients with Breast Cancer Treated with Chemotherapy
Factors angiogĂšnics; QuimioterĂ pia; EmbarĂ sFactores angiogĂ©nicos; Quimioterapia; EmbarazoAngiogenic factors; Chemotherapy; PregnancyHigh prevalence of placental-derived complications, such as preeclampsia and intrauterine growth restriction, has been reported in women with breast cancer (BC) treated with chemotherapy during pregnancy (PBC-CHT). Aim: To ascertain whether PBC-CHT is associated with an imbalance of angiogenic factors, surrogate markers for placental insufficiency, that could explain perinatal outcomes. Methods: Prospective study between 2012 and 2016 in a single institution. Soluble fms-like tyrosine kinase (sFlt-1), placental growth factor (PlGF), and soluble endoglin (sEng) in maternal blood were assessed throughout pregnancy in 12 women with BC and 215 controls. Results: Cancer patients were treated with doxorubicin-based regimes and with taxanes. Ten PBC-CHT (83%) developed obstetrical complications. At the end of the third trimester, significantly higher levels of sFlt-1; sFlt-1/PGF ratio, and sEng levels were observed in BC women as compared to controls. Moreover; there was a significant correlation between plasma levels of sFlt-1 and the number of chemotherapy cycles administered. Besides, more chemotherapy cycles correlated with lower birthweight and head circumference at birth. Conclusions: Women with BC treated during pregnancy showed an antiangiogenic state compatible with placental insufficiency. Angiogenic factors could be useful in the clinical obstetric management of these patients; although further studies will be required to guide clinical decision-making.This study was funded by the Spanish Research Project in Health funded by ISCIII, the state plan for scientific and technical research and innovation 2015â2018, and European Regional Development Fund (ERDF), ref. PI15/02252. This study was also supported in part by RETICS âMaternal and Child Health and Development Networkâ (SAMID Network), funded by the PN I + D + i 2008â2016 (Spain), ISCIII-Sub-Directorate General for Research Assessment and Promotion, and the European Regional Development Fund (ERDF), ref. RD12/0026 and RD16/0022. O.S. was supported by SAMID Network (RD12/0026/0016 and RD16/0022/0015) and S.M. was supported by âPaseico de la mamaâ
Cerebrospinal fluid biomarker supported diagnosis of Creutzfeldt-Jakob disease and rapid dementias: a longitudinal multicentre study over 10 years
To date, cerebrospinal fluid analysis, particularly protein 14-3-3 testing, presents an important approach in the identification of Creutzfeldt-Jakob disease cases. However, one special point of criticism of 14-3-3 testing is the specificity in the differential diagnosis of rapid dementia. The constant observation of increased cerebrospinal fluid referrals in the national surveillance centres over the last years raises the concern of declining specificity due to higher number of cerebrospinal fluid tests performed in various neurological conditions. Within the framework of a European Community supported longitudinal multicentre study (âcerebrospinal fluid markers') we analysed the spectrum of rapid progressive dementia diagnoses, their potential influence on 14-3-3 specificity as well as results of other dementia markers (tau, phosphorylated tau and amyloid-ÎČ1-42) and evaluated the specificity of 14-3-3 in Creutzfeldt-Jakob disease diagnosis for the years 1998-2008. A total of 29 022 cerebrospinal fluid samples were analysed for 14-3-3 protein and other cerebrospinal fluid dementia markers in patients with rapid dementia and suspected Creutzfeldt-Jakob disease in the participating centres. In 10 731 patients a definite diagnosis could be obtained. Protein 14-3-3 specificity was analysed for Creutzfeldt-Jakob disease with respect to increasing cerebrospinal fluid tests per year and spectrum of differential diagnosis. Ring trials were performed to ensure the comparability between centres during the reported time period. Protein 14-3-3 test specificity remained high and stable in the diagnosis of Creutzfeldt-Jakob disease during the observed time period across centres (total specificity 92%; when compared with patients with definite diagnoses only: specificity 90%). However, test specificity varied with respect to differential diagnosis. A high 14-3-3 specificity was obtained in differentiation to other neurodegenerative diseases (95-97%) and non-neurological conditions (91-97%). We observed lower specificity in the differential diagnoses of acute neurological diseases (82-87%). A marked and constant increase in cerebrospinal fluid test referrals per year in all centres did not influence 14-3-3 test specificity and no change in spectrum of differential diagnosis was observed. Cerebrospinal fluid protein 14-3-3 detection remains an important test in the diagnosis of Creutzfeldt-Jakob disease. Due to a loss in specificity in acute neurological events, the interpretation of positive 14-3-3 results needs to be performed in the clinical context. The spectrum of differential diagnosis of rapid progressive dementia varied from neurodegenerative dementias to dementia due to acute neurological conditions such as inflammatory diseases and non-neurological origi
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