1,942 research outputs found
Unconventional magnetism in all-carbon nanofoam
We report production of nanostructured carbon foam by a high-repetition-rate,
high-power laser ablation of glassy carbon in Ar atmosphere. A combination of
characterization techniques revealed that the system contains both sp2 and sp3
bonded carbon atoms. The material is a novel form of carbon in which
graphite-like sheets fill space at very low density due to strong hyperbolic
curvature, as proposed for ?schwarzite?. The foam exhibits ferromagnetic-like
behaviour up to 90 K, with a narrow hysteresis curve and a high saturation
magnetization. Such magnetic properties are very unusual for a carbon
allotrope. Detailed analysis excludes impurities as the origin of the magnetic
signal. We postulate that localized unpaired spins occur because of topological
and bonding defects associated with the sheet curvature, and that these spins
are stabilized due to the steric protection offered by the convoluted sheets.Comment: 14 pages, including 2 tables and 7 figs. Submitted to Phys Rev B 10
September 200
Magneto-optic Kerr effect in a spin-polarized zero-moment ferrimagnet
The magneto-optical Kerr effect (MOKE) is often assumed to be proportional to
the magnetisation of a magnetically ordered metallic sample; in metallic
ferrimagnets with chemically distinct sublattices, such as rare-earth
transition-metal alloys, it depends on the difference between the sublattice
contributions. Here we show that in a highly spin polarized, fully compensated
ferrimagnet, where the sublattices are chemically similar, MOKE is observed
even when the net moment is strictly zero. We analyse the spectral ellipsometry
and MOKE of Mn 2 Ru x Ga, and show that this behaviour is due to a highly
spin-polarized conduction band dominated by one of the two manganese
sublattices which creates helicity-dependent reflectivity determined by a broad
Drude tail. Our findings open new prospects for studying spin dynamics in the
infra-red.Comment: 7 pages, 7 figure
Generation of spin currents via Raman scattering
We show theoretically that stimulated spin flip Raman scattering can be used
to inject spin currents in doped semiconductors with spin split bands. A pure
spin current, where oppositely oriented spins move in opposite directions, can
be injected in zincblende crystals and structures. The calculated spin current
should be detectable by pump-probe optical spectroscopy and anomalous Hall
effect measurement
Indoor Air Quality Design and Control in Low-Energy Residential Buildings: Current challenges, selected case studies and innovative solutions covering indoor air quality, ventilation design and control in residences. International Energy Agency Report, Energy in Buildings and Communities Programme, IEA EBC Annex 68
The objective of Subtask 4 in the IEA EBC Annec 68 was to integrate knowledge and results from remaining Subtasks and present them in the context with current knowledge. The focus of the Subtask 4 was on practitioners dealing with ensuring high Indoor Air Quality (IAQ) in modern low-energy residences, the demands and challenges they meet during daily work. This especially includes architects and ventilation designers, facility managers, property developers and employees of public authorities. This publication is a result if Subtask 4’s work. It brings a collection of 24 “case studies” related to IAQ design and control in Low-Energy Residential Buildings. By a “case study” we mean a real life construction project, laboratory investigation or a simulation study that provides innovative approach. The case studies were selected to give the practitioners new insigts, inspiration and motivation to go along new paths leading to sustainable and comfortable homes of the future. The report is organized into three main chapters: “Ways to design residential ventilation in the future” and “Towards better performance and user satisfaction”. The descriptions of case studies are accompanied by “lessons learned” sections aiming directly at practical utilization of results as well as recommended future reading section providing the most important references
The motor function measure to study limitation of activity in children and adults with Charcot-Marie-Tooth disease
AbstractObjectiveTo study the applicability and responsiveness of the motor function measure (total score and sub-scores D1, D2 and D3) in patients with Charcot-Marie-Tooth disease.Patients and methodsTwo hundred and thirty-three patients aged 4–86 years were included in the descriptive study. Scores and sub-scores were analyzed by age and by disease subtypes. Sensitivity to change (responsiveness) was estimated in patients having had at least two evaluations with at least six months between the first and the second.ResultsMotor function measure scores decrease with age, especially sub-scores D1 and D3. There were no significant differences between the scores according to type of Charcot-Marie-Tooth disease. The scores were significantly higher for ambulatory than for non-ambulatory patients. Significant responsiveness was demonstrated only in type 2 Charcot-Marie-Tooth disease.Discussion/conclusionsOur results suggest that, especially for D1 and D3 sub-scores, the motor function measure is a reliable and valid outcome measure that can be usefully applied in longitudinal follow-up. Studies of longer duration could demonstrate its responsiveness in other Charcot-Marie-Tooth disease subtypes
Establishment of proteome reference maps for somatic and zygotic embryos of Cyclamen persicum mill.
Comprehensive proteomic characterizations were performed aiming to create proteome reference maps for somatic and zygotic embryos of Cyclamen persicum. Separation by two dimensional isoelectric focusing - sodium dodecyl sulfate polyacrylamide gel electrophoresis led to a resolution of more than 800 protein spots for each tissue. Approximately 70% of the spots likewise appeared in both zygotic and in somatic embryo's protein fractions. However, differential gel electrophoresis analyses revealed pronounced differences in abundances for the majority of proteins present in both tissues. MS analyses for 300 reproducible spots in total (263 of the zygotic embryos' protein fraction and 37 spots appearing specifically in the somatic embryos' proteome) led to identification of 261 proteins, 35 of which were specific or highly abundant in gels of the somatic embryo's tissue. Most identified proteins were found to be involved in glycolysis or gluconeogenesis and stress response pathways
Clinical Performance of the Automated LIAISON® Meridian H. pylori SA Stool Antigen Test
Background. Antigens derived from Helicobacter pylori can be used as stool biomarkers to assist in the diagnosis of H. pylori infection. Since current assays have variable performance, we assessed the clinical performance of the automated LIAISON® Meridian H. pylori SA chemiluminescent immunoassay against more invasive biopsy tests that are considered to be the "gold standard" (Composite Reference Method). Methods. This prospective multisite study enrolled patients undergoing an esophagogastroduodenoscopy with collection of biopsy and stool specimens. Adult patients (≥22 years) participated in the study from February 2017 to August 2018. Specimens of the stomach were tested by three methods, known as the Composite Reference Method: (1) histological evaluation, (2) culture of the organism, and (3) rapid urease detection test. H. pylori in stool was detected using the automated LIAISON® Meridian H. pylori SA assay, a chemiluminescent immunoassay. Statistical analyses were performed using MedCalc 18.11.6. Results. 277 patients (63% female) were included in the study. The prevalence of infected subjects was 24.2% in this study cohort. Clinical performance assessed against the Composite Reference Method showed very good agreement (Cohen's kappa=0.922), with good sensitivity (95.5%) and specificity (97.6%). Reproducibility study results showed total imprecision ranging from 3.1% to 13.9% CV. Conclusion. The automated LIAISON® Meridian H. pylori SA assay brings reliable noninvasive testing for H. pylori to the laboratory that is in very good agreement with the current, more invasive biopsy-based methods such as histology, culture, or rapid urease test. The clinical trial identifiers are NCT03060746 (pretherapy) and NCT03060733 (posttherapy)
Towards a better understanding of somatic embryogenesis in Cyclamen persicum
Somatic embryogenesis in Cyclamen persicum was first reported in 1984 and has potential applications for propagation and breeding of this economically important ornamental crop. This in vitro regeneration system can be used for vegetative propagation of parental lines of F1 hybrids and elite plants, production of artificial seeds, Agrobacterium tumefaciens-mediated genetic transformation, long-term cryopreservation, protoplast to plant regeneration and somatic hybridization. Somatic embryogenesis was shown to be a powerful propagation system for some C. persicum genotypes, but commercial application in large scale so far is hindered by several limitations, i.e., asynchronous development, malformations or secondary somatic embryogenesis. However, recent molecular approaches by transcriptomic and proteomic analyses were undertaken in order to better understand and control this in vitro regeneration system and to overcome these problems. Our studies aim at comparing somatic embryos to their zygotic counterparts regarding their proteomes. Protein separation by two dimensional isoelectric focusing - sodium do-decyl sulfate polyacrylamide gel electrophoresis led to a resolution of about 1000 protein spots per gel, of which the first 253 were identified by mass spectrometry. Most were found to be involved in glycolysis/gluconeogenesis and stress response pathways. A proteome reference map of zygotic embryos will be publicly released soon and may serve as a basis for further investigations and improvements of somatic embryogenesis
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