Magnetoresistance and surface roughness study of the initial growth of electrodeposited Co/Cu multilayers

The giant magnetoresistance (GMR) effect has been widely investigated on electrodeposited ferromagnetic/non-magnetic (FM/NM) multilayers generally containing a large number of bilayers. In most applications of the GMR effect, layered structures consisting of a relatively small number of consecutive FM and NM layers are used. It is of great interest, therefore, to investigate the initial stages of GMR multilayer film growth by electrodeposition. In the present work we have extended our previous studies on ED GMR multilayers to layered structures with a total thickness ranging from a few nanometers up to 70 nm. The evolution of the surface roughness and electrical transport properties of such ultrathin ED Co/Cu layered structures was investigated. Various layer combinations were produced including both Co and Cu either as starting or top layers in order (i) to see differences in the nucleation of the first layer and (ii) to trace out the effect of the so called exchange reaction. Special attention was paid to measure the field dependence of the magnetoresistance, MR(H) in order to derive information for the appearance of superparamagnetic regions in the magnetic layers. This proved to be helpful for monitoring the evolution of the layer microstructure at each step of the deposition sequence

Minimal information for studies of extracellular vesicles (MISEV2023): From basic to advanced approaches

Extracellular vesicles (EVs), through their complex cargo, can reflect the state of their cell of origin and change the functions and phenotypes of other cells. These features indicate strong biomarker and therapeutic potential and have generated broad interest, as evidenced by the steady year-on-year increase in the numbers of scientific publications about EVs. Important advances have been made in EV metrology and in understanding and applying EV biology. However, hurdles remain to realising the potential of EVs in domains ranging from basic biology to clinical applications due to challenges in EV nomenclature, separation from non-vesicular extracellular particles, characterisation and functional studies. To address the challenges and opportunities in this rapidly evolving field, the International Society for Extracellular Vesicles (ISEV) updates its 'Minimal Information for Studies of Extracellular Vesicles', which was first published in 2014 and then in 2018 as MISEV2014 and MISEV2018, respectively. The goal of the current document, MISEV2023, is to provide researchers with an updated snapshot of available approaches and their advantages and limitations for production, separation and characterisation of EVs from multiple sources, including cell culture, body fluids and solid tissues. In addition to presenting the latest state of the art in basic principles of EV research, this document also covers advanced techniques and approaches that are currently expanding the boundaries of the field. MISEV2023 also includes new sections on EV release and uptake and a brief discussion of in vivo approaches to study EVs. Compiling feedback from ISEV expert task forces and more than 1000 researchers, this document conveys the current state of EV research to facilitate robust scientific discoveries and move the field forward even more rapidly

Structure of sputtered nanocomposite CrC[sub x]∕a-C:H thin films

This work presents the structural evolution of nanocomposite CrCx∕a-C:H coatings prepared by unbalanced magnetron sputtering of a metallic Cr target in Ar+CH4 glow discharges using low negative dc bias voltages. Raman spectroscopy and x-ray photoelectron spectroscopy were used to characterize the phase composition and the chemical bonding in the films deposited at different experimental conditions. The results were correlated to the chemical composition obtained by elastic recoil detection analysis. The coating microstructure was investigated on selected samples by high-resolution transmission electron microscopy combined with electron energy-loss spectroscopy analysis. The nanocomposite coatings can be divided into hard CrCx dominated films, when prepared at low CH4 partial pressure to total pressure (pt) ratios (pCH4/pt0.4. The structure of the low-friction a-C:H dominated coatings consists of 2–10nm sized fcc CrC crystallites embedded in a Cr containing a-C:H matrix

Detection and Characterization of Small Molecule Interactions with Fibrillar Protein Aggregates Using Microscale Thermophoresis

Neurodegenerative diseases such as Parkinson’s and Alzheimer’s disease share the pathological hallmark of fibrillar protein aggregates. The specific detection of these protein aggregates by positron emission tomography (PET) in the patient brain can yield valuable information for diagnosis and disease progression. However, the identification of novel small compounds that bind fibrillar protein aggregates has been a challenge. In this study, microscale thermophoresis (MST) was applied to assess the binding affinity of known small molecule ligands of α-synuclein fibrils, which were also tested in parallel in a thioflavin T fluorescence competition assay for further validation. In addition, a MST assay was also developed for the detection of the interaction between a variety of small molecules and tau fibrils. The results of this study demonstrate that MST is a powerful and practical methodology to quantify interactions between small molecules and protein fibrillar aggregates, which suggests that it can be applied for the identification and development of PET radioligands and potentially of therapeutic candidates for protein misfolding diseases

Nuclear Safety Research Support Facilities for Existing and Advanced Reactors: 2021 Update

At its 61st meeting in June 2017, the Nuclear Energy Agency (NEA) Committee on the Safety of Nuclear Installations (CSNI) decided to establish a Senior Expert Group on Safety Research (SESAR) to update previous assessments of capabilities and facilities required to support the safety of nuclear installations. The NEA issued a report on this activity in 2001 entitled Nuclear Safety Research in OECD Countries: Major Facilities and Programmes at Risk. Six years later, a followon activity resulted in the publication SESAR/SFEAR: Nuclear Safety Research in OECD Countries – Support Facilities for Existing and Advanced Reactors (2007). The SESAR/SFEAR2’s mandate is as follows: “The Senior Expert Group on Safety Research/ Support Facilities for Existing and Advanced Reactors 2 (SESAR/SFEAR2) is responsible for reviewing and updating the previous SESAR assessments of research facilities required to support the safety of nuclear installations. The group shall recommend actions to be taken by the CSNI and its member countries to facilitate broader use and sustained operation of essential research facilities required to support nuclear safety.” The activity described in this report builds upon and updates the previous work, expanding its scope to cover advanced reactors, including evaluations performed by the Task Group on Advanced Reactor Experimental Facilities (TAREF) and the emergence of several proposed molten salt and small modular reactor designs. In addition, although the need to maintain experimental databases was recognised as an important issue, it was not treated specifically in previous reports; the present report therefore makes some direct recommendations regarding database maintenance

Neutronics Benchmark of CEFR Start-Up Tests: temperature coefficient, sodium void worth, and swap reactivity

The China Institute of Atomic Energy (CIAE) proposed some of the China Experimental Fast Reactor (CEFR) neutronics start-up test data for the IAEA benchmark within the scope of the IAEA’s coordinated research activity. The coordinated research project (CRP) on “Neutronics Benchmark of CEFR Start-Up Tests” was launched in 2018. The benchmark aims to perform validation and verification (V&V) of the physical models and the neutronics simulation codes by comparing calculation results against collected experimental data. Twenty-nine participating research organizations finished performing independent blind calculations and refined their calculation results by referring to measurement data. The paper introduces the following three kinds of reactivity measurements in the CEFR start-up test and presents the results by participants: temperature coefficient, sodium void reactivity, and swap reactivity. First, for measuring temperature coefficients, ten sets of data were obtained by increasing and decreasing the temperature. The control rod position is changed for each temperature to maintain the reactor as critical. Second, sodium void reactivity is measured by replacing a fuel SA with vacuum-sealed SA and searching for the critical position of control rods. Third, for measuring the swap reactivity, fuel subassembly is replaced by stainless subassembly, and stainless subassembly is switched with one fuel subassembly. Swap reactivities are measured in two different ways, with more than two control rods moving to find the criticality of the core in the ‘Multiple Rods’ case and only one control rod moving in the ‘Single Rod’ case. All three reactivities are obtained by combining control rod worth for changed rod position and criticality difference. The comparison shows that uncertainty of calculations, modeling errors, and inaccurately determined control assembly worth make it challenging to calculate the temperature coefficient precisely. Meanwhile, the void worth and the swap reactivity results have similar trends and show good agreement with measurement

Properties, Solution State Behavior, and Crystal Structures of Chelates of DOTMA

[Image: see text] The chemistry of polyamino carboxylates and their use as ligands for Ln(3+) ions is of considerable interest from the point of view of the development of new imaging agents. Of particular interest is the chemistry of the macrocyclic ligand 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) and its derivatives. Herein we report that the tetramethylated DOTA derivative, DOTMA, possess several properties that, from an imaging agent development point of view, are more advantageous than those of the parent DOTA. In particular, the Ln(3+) chelates of DOTMA exhibit a marked preference for the monocapped twisted square antiprismatic coordination isomer which imparts more rapid water exchange kinetics on the chelates; τ(M)(298) was determined to be 85 ns for GdDOTMA. Differential analysis of the (17)O R(2)(ρ) temperature profiles of both GdDOTA and GdDOTMA afforded the τ(M)(298) values for the square (SAP) and twisted square antiprismatic (TSAP) isomers of each chelate that were almost identical: 365 ns (SAP) and 52 ns (TSAP). The origin of this accelerated water exchange in the TSAP isomer appears to be the slightly longer Gd–OH(2) bond distance (2.50 Å) that is observed in the crystal structure of GdDOTMA which crystallizes in the P(2) space group as a TSAP isomer. The Ln(3+) chelates of DOTMA also exhibit high thermodynamic stabilities ranging from log K(ML) = 20.5 for CeDOTMA, 23.5 for EuDOTMA and YbDOTMA comparable to, but a shade lower than, those of DOTA