Valon emissio ja eteneminen spatiaalisesti dispersiivisissä metamateriaaleissa

Optical metamaterials are nanostructured materials that can be designed to exhibit extraordinary optical characteristics. Consisting of artificial nanoparticles called "metamolecules", optical metamaterials are usually spatially dispersive, and as a result, their optical response is can depend not only on light polarization but also on propagation direction. In this thesis develop analytical and numerical calculation tools to study the propagation and generation of light in such materials. To address all relevant phenomena, we describe the materials in terms of wave parameters, which are refractive index and impedance determined for each plane wave separately. We develop an approach to analyze the interaction of optical beams with metamaterial slabs, and introduce a method valid even for materials that do not support polarization modes. We also develop a method to calculate the optical fields created by quantum emitters inside spatially dispersive metamaterial slabs. Equipped with these tools we design and analyze metamaterials with unique optical properties including compensation of optical diffraction, direction-sensitive reflectivity, interface-shaped wavefronts of a multimode light source, and highly directional spontaneous emission.Optiset metamateriaalit ovat nanorakenteisia materiaaleja joilla on tavallisesta poikkeavia optisia ominaisuuksia. Optiset metamateriaalit koostuvat keinotekoisista nanopartikkeleista, "metamolekyyleistä", ja ovat usein spatiaalisesti dispersiivisiä, jonka seurauksena niiden optinen vaste riippuu valon polarisaation lisäksi etenemissuunnasta. Tässä diplomityössä kehitetään analyyttisiä ja numeerisia menetelmiä tutkimaan valon etenemistä ja generointia optisissa metamateriaaleissa. Jotta kaikki metamateriaalien optiset ilmiöt voidaan ottaa huomioon, materiaalien karakterisointiin käytetään aaltoparametrejä, jotka ovat jokaisen tasoaallon oma taitekerroin ja aaltoimpedanssi. Työssä kehitetään menetelmä optisten säteiden ja metamateriaalikalvojen vuorovaikutuksen analysointiin, sekä menetelmä joka soveltuu tähän myös materiaaleissa, joilla ei ole polarisaatiomoodeja. Työssä kehitetään myös menetelmä, jolla voidaan laskea spatiaalisesti dispersiiviseen metamateriaalikalvoon upotetun säteilylähteen optinen kenttä. Näiden työkalujen avulla diplomityössä kehitetään ja analysoidaan metamateriaaleja, joilla on ainutlaatuisia optisia ominaisuuksia kuten valon diffraktion kompensointi, suuntariippuva heijastavuus, rajapintaan muotoutuvat aaltorintamat monimuotovalonlähteestä ja suunnattu spontaani emissio

Cantilever-enhanced photoacoustic measurement of HTO in water vapor

A photoacoustic detection of tritiated water (HTO) is presented. The method uses cantilever-enhanced photoacoustic spectroscopy (CEPAS) to reach sub-ppb sensitivity for HTO in the gas phase. A noise equivalent concentration of 0.88 ppb is reached with a sampling time of 1 min. The high performance and small sample volume of CEPAS allows sensitive detection of HTO from a sample with low total activity.Peer reviewe

Optimal peripheral nerve stimulation intensity for paired associative stimulation with high-frequency peripheral component in healthy subjects

Publisher Copyright: © 2022, The Author(s).Paired associative stimulation (PAS) with high-frequency peripheral nerve stimulation (PNS), called “high-PAS”, induces motor-evoked potential (MEP) potentiation in healthy subjects and improves muscle activity and independence in incomplete spinal cord injury patients. Data on optimal PNS intensity in PAS are scarce. In a high-PAS protocol, PNS intensity is defined as “minimal intensity required to produce F-responses”. We sought to further refine this definition and to investigate how PNS intensity affects PAS outcome. Two experiments were performed on 10 healthy subjects where MEP amplitude change was measured 0, 30, and 60 min after PAS. In the first experiment, the intensity required to achieve 7/10 persistence of F-responses was used to define PNS intensity level. In the second experiment, we used the intensity required to achieve 1/10 persistence (“baseline”). In addition, we applied this intensity at + 25%, − 25%, and − 50% levels. In the first experiment, PAS did not produce significant MEP potentiation. In the second experiment, PAS produced statistically significant MEP potentiation, with PNS intensity of “baseline” and “baseline − 25%” levels but not at + 25% or − 50% levels. In conclusion, for PAS utilizing high-frequency PNS, the intensity required to achieve 1/10 F-response persistence or the intensity 25% lower produces significant MEP potentiation in healthy subjects.Peer reviewe

Effects of dietary yeast inclusion and acute stress on post-prandial whole blood profiles of dorsal aorta-cannulated rainbow trout

Yeast is a potential alternative to fish meal in diets for farmed fish, yet replacing more than 50 % of fish meal results in reduced fish growth. In a 4-week experiment, 15 rainbow trout (Oncorhynchus mykiss) were cannulated and fed three diets each week: 30 % fish meal as a control (FM); 60 % replacement of fish meal protein, on a digestible basis, with Saccharomyces cerevisiae (SC); and 60 % replacement with Wickerhamomyces anomalus and S. cerevisiae mix (WA). Blood was collected at 0, 3, 6, 12 and 24 h after feeding. In the final week, fish were exposed to a 1-min netting stressor to evaluate possible diet-stress interactions. Significant increases in pH, TCO2, HCO3 and base excess were found after fish were fed the SC and WA diets compared with FM, which elevated blood alkaline tides. Yeast ingredients had lower buffering capacity and ash content than fish meal, which explained the increase in alkaline tides. In addition, fish fed the WA diet had significantly reduced erythrocyte area and fish fed SC and WA diets had increased mean corpuscular haemoglobin levels, indicating haemolytic anaemia. Higher levels of nucleic acid in yeast-based diets and potentially higher production of reactive oxygen species were suspected of damaging haemoglobin, which require replacement by smaller immature erythrocytes. Acute stress caused the expected rise in cortisol and glucose levels, but no interaction with diet was found. These results show that replacing 60 % of fish meal protein with yeasts can induce haemolytic anaemia in rainbow trout, which may limit yeast inclusion in diets for farmed fish

PACSIN2 accelerates nephrin trafficking and is up-regulated in diabetic kidney disease

Nephrin is a core component of podocyte (glomerular epithelial cell) slit diaphragm and is required for kidney ultrafiltration. Down-regulation or mislocalization of nephrin has been observed in diabetic kidney disease (DKD), characterized by albuminuria. Here, we investigate the role of protein kinase C and casein kinase 2 substrate in neurons 2 (PACSIN2), a regulator of endocytosis and recycling, in the trafficking of nephrin and development of DKD. We observe that PACSIN2 is up-regulated and nephrin mislocalized in podocytes of obese Zucker Diabetic Fatty (ZDF) rats that have altered renal function. In cultured podocytes, PACSIN2 and nephrin colocalize and interact. We show that nephrin is endocytosed in PACSIN2-positive membrane regions and that PACSIN2 overexpression increases both nephrin endocytosis and recycling. We identify rabenosyn-5, which is involved in early endosome maturation and endosomal sorting, as a novel interaction partner of PACSIN2. Interestingly, rabenosyn-5 expression is increased in podocytes in obese ZDF rats, and, in vitro, its overexpression enhances the association of PACSIN2 and nephrin. We also show that palmitate, which is elevated in diabetes, enhances this association. Collectively, PACSIN2 is up-regulated and nephrin is abnormally localized in podocytes of diabetic ZDF rats. In vitro, PACSIN2 enhances nephrin turnover apparently via a mechanism involving rabenosyn-5. The data suggest that elevated PACSIN2 expression accelerates nephrin trafficking and associates with albuminuria.Peer reviewe

Study of (n,xng) reactions on 238U

Prompt-gamma spectroscopy and time-of-flight techniques were used to measure (n,xn gamma) cross-sections on several nuclei of interest for nuclear reactors. Experiments were performed at the GELINA facility which provides a pulsed white neutron beam of maximum energy about 20 MeV. Preliminary results concerning 238U will be presented. This work was supported by PACEN/GEDEPEONand by the European Commission within the Sixth Framework Programme through I3-EFNUDAT (EURATOMcontract no. 036434) and NUDAME (Contract FP6-516487), and within the Seventh Framework Programme through EUFRAT (EURATOM contract no. FP7-211499) and through ANDES (EURATOM contract no. FP7-249671).JRC.D.4-Standards for Nuclear Safety, Security and Safeguard

JRC data for the Ti-48 standard

A measurement of the 48Ti(n,n’gamma)48Ti reaction was performed at the GELINA neutron source of EC-JRC-IRMM using the GAINS spectrometer with the purpose of establishing a new gamma-ray standard for neutron induced cross section measurements. A natural target was used and the gamma-production cross section was measured for 10 transitions in the neutron energy range 0-18 MeV. The lowest achieved uncertainty was 4.8%.JRC.D.4-Standards for Nuclear Safety, Security and Safeguard

The Effects of Intensive Weight Reduction on Body Composition and Serum Hormones in Female Fitness Competitors

Worries about the potential negative consequences of popular fat loss regimens for aesthetic purposes in normal weight females have been surfacing in the media. However, longitudinal studies investigating these kinds of diets are lacking. The purpose of the present study was to investigate the effects of a 4-month fat-loss diet in normal weight females competing in fitness-sport. In total 50 participants finished the study with 27 females (27.2 +/- 4.1 years) dieting for a competition and 23 (27.7 +/- 3.7 years) acting as weight-stable controls. The energy deficit of the diet group was achieved by reducing carbohydrate intake and increasing aerobic exercise while maintaining a high level of protein intake and resistance training in addition to moderate fat intake. The diet led to a similar to 12% decrease in body weight (P <0.001) and a similar to 3550% decrease in fat mass (DXA, bioimpedance, skinfolds, P <0.001) whereas the control group maintained their body and fat mass (diet x group interaction P <0.001). A small decrease in lean mass (bioimpedance and skinfolds) and in vastus lateralis muscle cross-sectional area (ultrasound) were observed in diet (P <0.05), whereas other results were unaltered (DXA: lean mass, ultrasound: triceps brachii thickness). The hormonal system was altered during the diet with decreased serum concentrations of leptin, triiodothyronine (T3), testosterone (P <0.001), and estradiol (P <0.01) coinciding with an increased incidence of menstrual irregularities (P <0.05). Body weight and all hormones except T3 and testosterone returned to baseline during a 34 month recovery period including increased energy intake and decreased levels aerobic exercise. This study shows for the first time that most of the hormonal changes after a 3550% decrease in body fat in previously normal-weight females can recover within 34 months of increased energy intake.Peer reviewe

EUFRAT, Open Access to the nuclear research infrastructure at JRC Geel

Open access activities to the nuclear research facilities operated at the Joint Research Centre (JRC) in Geel are reported. These activities are carried out by the unit Standards for Nuclear Safety, Security and Safeguards of the Directorate for Nuclear Safety and Security as part of its work programme. The open access activities at JRC Geel run since 2014 as an institutional programme under the EURATOM work programme. In 2017 the JRC decided to start a JRC-wide open access scheme to its research infrastructure co-ordinated by the Directorate for Strategy, Work Programme and Resources. The transition to a JRC-wide open access scheme is discussed and the results of the first two calls for proposals during 2017 and 2018 are summarised.JRC.G.2-Standards for Nuclear Safety, Security and Safeguard