Phase separation and structure formation in gadolinium based liquid and glassy metallic alloys

In this PhD research the liquid-liquid phase separation phenomena in Gd-based alloys was investigated in terms of phase equilibria, microstructure formation upon quenching the melt and corresponding magnetic properties of phase-separated metallic glasses. The phase diagrams of the binary subsystems Gd-Zr and Gd-Ti were experimentally reassessed. Especially the phase equilibria with the liquid phase could be determined directly by combining in situ high energy synchrotron X-ray diffraction with electrostatic levitation of the melt. The Gd-Zr system is of eutectic type with a metastable miscibility gap. The eutectic composition at 18 ± 2 at.% Zr, the liquidus line and the coexistence of bcc-Zr and bcc-Gd at elevated temperature could be determined. The Gd-Ti system is a monotectic system. The experimental observations in this work led to improved new Gd-Zr and Gd-Ti phase diagrams. The phase equilibria of the ternary Gd-Ti-Co system were analyzed for two alloy compositions. The XRD patterns for molten Gd35Ti35Co30 gave direct evidence for the coexistence of two liquid phases formed by liquid-liquid phase separation. The first experimental and thermodynamic assessment of the ternary Gd–Ti–Co system revealed that the stable miscibility gap of binary Gd–Ti extends into the ternary Gd–Ti–Co system (up to about 30 at.% Co). New phase-separated metallic glasses were synthesized in Gd-TM-Co-Al (TM = Hf, Ti or Zr) alloys. The microstructure was characterized in terms of composition and cooling rate dependence of phase separation. Due to large positive enthalpy of mixing between Gd on the one side and Hf, Ti or Zr on the other side, the alloys undergo liquid-liquid phase separation during rapid quenching the melt. The parameters determining the microstructure development during phase separation are the thermodynamic properties of the liquid phase, kinetic parameters and quenching conditions. By controlling these parameters and conditions the microstructure can be tailored both at microscopic and macroscopic length scales. This includes either droplet-like or interconnected microstructures at the microscopic level and glass-glass or glass-crystalline composites at the macroscopic level. Essential parameter for the quenched in microstructure is the temperature dependence of liquid-liquid phase separation, which is determined by the chemical composition of the alloy: on the one hand, earlier and/or later stages of spinodal decomposition or almost homogeneous glassy states are obtained if the critical temperature of miscibility gap Tc is close to the glass transition temperature Tg; and on the one hand, coarsening and secondary precipitations of the liquids are obtained if Tc is much higher than Tg. Finally, the influence of the microstructure developed by phase separation on their magnetic properties had been investigated. The saturation magnetization σS depends on the overall amount of Gd atoms in the alloys and is not remarkably affected by phase separation processes. The Curie temperature TCurie of the magnetic transition is influenced by the changed chemical composition of the Gd-rich glassy phases compared to that of monolithic Gd-Co-Al glasses.In dieser Doktorarbeit wurde die flüssig-flüssig Phasenentmischung von Gd-basierten Legierungen hinsichtlich der Phasengleichgewichte, der Gefügeentwicklung während der Schmelzabschreckung und dazugehöriger magnetischer Eigenschaften, untersucht. Die Zustandsdiagramme der binären Untersysteme Gd-Zr undGd-Ti wurden experimentell ermittelt.. Insbesondere konnten die Phasengleichgewichte mit der flüssigen Phase mittels in-situ Röntgenbeugungsmessunngen an elektrostatisch levitierten Schmelzen direkt, bestimmt werden. Das Gd-Zr System stellt ein ein eutektisches Phasendiagram dar und besitzt eine metastabile Mischungslücke. Die eutektische Zusammensetzung wurde mit 18 ± 2 at.%Zr bestimmt und der Verlauf der Liquiduslinie bei erhöhten Temperaturen wurde experimentell ermittelt. Experimentell wurde die Koexistenz von kubisch-raumzentrierten Zr und Gd in einem Bereich bei hohen Temperaturen nachgewiesen. Das Gd-Ti-System ist von monotektischer Art. Die experimentellen Beobachtungen dieser Arbeit trugen wesentlich zur Verbesserung der Beschreibung der Phasendiagaramme Gd-Zr- und Gd-Ti-Phasenbei. Die Phasengleichgewichte des ternären Gd-Ti-Co-Systems wurde anhand zweier Legierungszusammensetzungen untersucht. Die Röntgenbeugungsdiffraktogramme der geschmolzenen Legiereung Gd35Ti35Co30 sind ein direkter Beleg für die Koexistenz zweier flüssiger Phasen, aufgrund der flüssig-flüssig Phasenentmischung. Die erste experimentelle und thermodynamische Auswertung des ternären Gd-Ti-Co-Systems zeigt, dass sich die stabile Mischungslücke des binären Gd-Ti-Systems ins ternäre Gd-Ti-Co-System bis zu ungefähr 30 at.% Co erstreckt. Es wurden neue Gd-TM-Co-Al (TM = Hf, Ti oder Zr)-basierte metallische Gläser, die separierte Phasen besitzen, hergestellt. Ihr Gefüge wurden hinsichtlich Zusammensetzung- und Abkühlratenabhängigkeit der Phasenentmischung charakterisiert. Aufgrund der großen positiven Mischungsenthalpie zwischen Gd auf der einen und Hf, Ti oder Zr auf der anderen Seite, weisen diese Legierungen eine flüssig-flüssig Phasenentmischung während der Abschreckung aus der Schmelze auf. Die Einflussgrößen, die die Gefügeentwicklung während der Phasenentmischung bestimmen, sind die thermodynamischen Eigenschaften der flüssigen Phase, die kinetische Parameter und die Abschreckbedingungen. Indem diese Parameter und Bedingungen kontrolliert werden, kann das Gefüge auf makro- sowie mikroskopischer Längenskala maßgeschneidert werden. Dies beinhaltet entweder tropfenförmige oder miteinander verbundene Gefüge auf einer mikroskopischen Skala und Glas-Glas oder Glas-Kristall Komposite auf einer makroskopischen Längenskala. Ein wesentlicher Parameter für das abgeschreckte Gefüge ist die Temperatur-Abhängigkeit der flüssig-flüssig Phasenentmischung, die durch die chemische Zusammensetzung der Legierung bestimmt wird. Frühere und/oder spätere Stadien der spinodalen Entmischung oder nahezu homogene amorphe Zustände können abhängig von dem Temperaturunterschied zwischen kritischer Temperatur der flüssig-flüssig Phasenentmischung und der Glasübergangstemperatur erhalten werden. Wenn die kritische Temperatur der Mischungslücke, Tc, viel höher ist als die des Glasübergangs, Tg, können makroskopische Vergröberungen der tropfenförmigen Verteilung der flüssigen Phase und sekundäre flüssige oder kristalline Ausscheidungen in den gebildeten amorphen Phasen erhalten werden. Durch die Phasenentmischung und die erhaltenen heterogenen Gefüge werden die magnetischen Eigenschaften beeinflusst.. Die Sättigungsmagnetisierung,σS, hängt von der gesamten Anzahl der Gd-Atome der Legierung ab und wird nicht bemerkenswert vom Phasenentmischungsprozess beeinflusst. Die Curie Temperatur TCurie wird im Vergleich zu monolithischen Gd-Co-Al Gläsern, und abhängig von der chemischen Zusammensetzung der Gd-reichen Phase, verändert

Lifestyle counselling by persuasive information and communications technology reduces prevalence of metabolic syndrome in a dose–response manner : a randomized clinical trial (PrevMetSyn)

AbstractObjectives:The aim was to investigate whether lifestyle changes produced by persuasive Information and Communication Technology (ICT) counselling can lower the prevalence of metabolic syndrome (MetS).Methods:A total of 532 participants (20–60 years, body mass index 27–35 kg/m²) were randomly assigned to six arms according to counselling type (no, short-term, or intensive) with or without ICT intervention. In this report the prevalence of MetS and its components were compared between no-ICT group and ICT group. Moreover, the frequency of the web information system usage was analysed for the number of logins, responses to weekly messages, and other record variables.Results:The ICT group had significantly lower proportion of MetS (33.7% vs. 45.3%, p = .022) than the no-ICT group at 2-year follow-up. In mixed model, the ICT group had lower prevalence of MetS than no-ICT group (OR 0.50, 95%CI 0.27–0.90) after intervention. The tertile with the highest utilization had 71% lower prevalence of MetS compared with the lowest utilization tertile or the no-ICT group.Conclusions:Web-based ICT is able to reduce the prevalence of MetS. In addition, higher utilization of the web information system is associated with a greater decrease in the prevalence of MetS.Key messagesOur internet health behaviour change support system based on persuasive design and cognitive behaviour therapy markedly reduces metabolic syndrome in overweight/obese subjects. As a stand-alone tool it may save healthcare personnel resources as it is suitable at a low cost for both obese/overweight patients and the public at large.Abstract Objectives:The aim was to investigate whether lifestyle changes produced by persuasive Information and Communication Technology (ICT) counselling can lower the prevalence of metabolic syndrome (MetS). Methods:A total of 532 participants (20–60 years, body mass index 27–35 kg/m²) were randomly assigned to six arms according to counselling type (no, short-term, or intensive) with or without ICT intervention. In this report the prevalence of MetS and its components were compared between no-ICT group and ICT group. Moreover, the frequency of the web information system usage was analysed for the number of logins, responses to weekly messages, and other record variables. Results:The ICT group had significantly lower proportion of MetS (33.7% vs. 45.3%, p = .022) than the no-ICT group at 2-year follow-up. In mixed model, the ICT group had lower prevalence of MetS than no-ICT group (OR 0.50, 95%CI 0.27–0.90) after intervention. The tertile with the highest utilization had 71% lower prevalence of MetS compared with the lowest utilization tertile or the no-ICT group. Conclusions:Web-based ICT is able to reduce the prevalence of MetS. In addition, higher utilization of the web information system is associated with a greater decrease in the prevalence of MetS.Key messages Our internet health behaviour change support system based on persuasive design and cognitive behaviour therapy markedly reduces metabolic syndrome in overweight/obese subjects. As a stand-alone tool it may save healthcare personnel resources as it is suitable at a low cost for both obese/overweight patients and the public at large

ReplaceNet: real-time replacement of a biological neural circuit with a hardware-assisted spiking neural network

Recent developments in artificial neural networks and their learning algorithms have enabled new research directions in computer vision, language modeling, and neuroscience. Among various neural network algorithms, spiking neural networks (SNNs) are well-suited for understanding the behavior of biological neural circuits. In this work, we propose to guide the training of a sparse SNN in order to replace a sub-region of a cultured hippocampal network with limited hardware resources. To verify our approach with a realistic experimental setup, we record spikes of cultured hippocampal neurons with a microelectrode array (in vitro). The main focus of this work is to dynamically cut unimportant synapses during SNN training on the fly so that the model can be realized on resource-constrained hardware, e.g., implantable devices. To do so, we adopt a simple STDP learning rule to easily select important synapses that impact the quality of spike timing learning. By combining the STDP rule with online supervised learning, we can precisely predict the spike pattern of the cultured network in real-time. The reduction in the model complexity, i.e., the reduced number of connections, significantly reduces the required hardware resources, which is crucial in developing an implantable chip for the treatment of neurological disorders. In addition to the new learning algorithm, we prototype a sparse SNN hardware on a small FPGA with pipelined execution and parallel computing to verify the possibility of real-time replacement. As a result, we can replace a sub-region of the biological neural circuit within 22 μs using 2.5 × fewer hardware resources, i.e., by allowing 80% sparsity in the SNN model, compared to the fully-connected SNN model. With energy-efficient algorithms and hardware, this work presents an essential step toward real-time neuroprosthetic computation

Using Gini coefficient to determining optimal cluster reporting sizes for spatial scan statistics

Background: Spatial and space–time scan statistics are widely used in disease surveillance to identify geographical areas of elevated disease risk and for the early detection of disease outbreaks. With a scan statistic, a scanning window of variable location and size moves across the map to evaluate thousands of overlapping windows as potential clusters, adjusting for the multiple testing. Almost always, the method will find many very similar overlapping clusters, and it is not useful to report all of them. This paper proposes to use the Gini coefficient to help select which of the many overlapping clusters to report. Methods: The Gini coefficient provides a quick and intuitive way to evaluate the degree of the heterogeneity of the collection of clusters, which is useful to explain how well the cluster collection reveal the underlying true cluster patterns. Using simulation studies and real cancer mortality data, it is compared with the traditional approach for reporting non-overlapping clusters. Results: The Gini coefficient can identify a more refined collection of non-overlapping clusters to report. For example, it is able to determine when it makes more sense to report a collection of smaller non-overlapping clusters versus a single large cluster containing all of them. It also fulfils a set of desirable theoretical properties, such as being invariant under a uniform multiplication of the population numbers by the same constant. Conclusions: The Gini coefficient can be used to determine which set of non-overlapping clusters to report. It has been implemented in the free SaTScan™ software version 9.3 (www.satscan.org)

Using Gini coefficient to determining optimal cluster reporting sizes for spatial scan statistics

BACKGROUND: Spatial and space–time scan statistics are widely used in disease surveillance to identify geographical areas of elevated disease risk and for the early detection of disease outbreaks. With a scan statistic, a scanning window of variable location and size moves across the map to evaluate thousands of overlapping windows as potential clusters, adjusting for the multiple testing. Almost always, the method will find many very similar overlapping clusters, and it is not useful to report all of them. This paper proposes to use the Gini coefficient to help select which of the many overlapping clusters to report. METHODS: The Gini coefficient provides a quick and intuitive way to evaluate the degree of the heterogeneity of the collection of clusters, which is useful to explain how well the cluster collection reveal the underlying true cluster patterns. Using simulation studies and real cancer mortality data, it is compared with the traditional approach for reporting non-overlapping clusters. RESULTS: The Gini coefficient can identify a more refined collection of non-overlapping clusters to report. For example, it is able to determine when it makes more sense to report a collection of smaller non-overlapping clusters versus a single large cluster containing all of them. It also fulfils a set of desirable theoretical properties, such as being invariant under a uniform multiplication of the population numbers by the same constant. CONCLUSIONS: The Gini coefficient can be used to determine which set of non-overlapping clusters to report. It has been implemented in the free SaTScan™ software version 9.3 (www.satscan.org)

Antibacterial Fluorinated Silica Colloid Superhydrophobic Surfaces

A superhydrophobic xerogel coating synthesized from a mixture of nanostructured fluorinated silica colloids, fluoroalkoxysilane, and a backbone silane is reported. The resulting fluorinated surface was characterized using contact angle goniometry, SEM, and AFM. Quantitative bacterial adhesion studies performed using a parallel plate flow cell demonstrated that the adhesion of Staphylococcus aureus and Pseudomonas aeruginosa were reduced by 2.08 ± 0.25 and 1.76 ± 0.12 log over controls, respectively. This simple superhydrophobic coating synthesis may be applied to any surface regardless of geometry and does not require harsh synthesis or processing conditions, making it an ideal candidate as a biopassivation strategy

In situ X-ray based analysis of anode materials for lithium-ion batteries: Current status and future implications

The past several decades witnessed a significant advance in the X-ray based analytical devices, which were employed in various applications ranging from airport security to material analysis. Particularly, since the early 1990s, much work has been devoted to employ various kinds of real time (in situ) X-ray based analytical tools such as in situ X-ray diffractometers (XRD), in situ X-ray absorption spectroscopy, and in situ X-ray tomography to understand the redox reactions within the lithium-ion batteries. Amongst components in the lithium-ion batteries, anode materials play an important role in that they are responsible for Li+ storage during the charging process. Reaction mechanisms of graphite, Si, and many other prospective anode materials have been elucidated by various in situ X-ray analytical tools but none of the comprehensive summary and evaluation on the current status of the research and future directions on employing in situ X-ray based analysis for further investigating these anode materials are presented up to this point. In this review, we have examined and highlighted our focus on X-ray based analysis that was used to probe the reaction pathway of various anode materials used for lithium-ion batteries, which provides a milestone and comprehensive understanding for reaction mechanism of anode materials in lithium-ion batteries using in situ X-ray methods

Efficacy and safety of rapid intermittent bolus compared with slow continuous infusion in patients with severe hypernatremia (SALSA II trial): a study protocol for a randomized controlled trial

Background Hypernatremia is a common electrolyte disorder in children and elderly people and has high short-term mortality. However, no high-quality studies have examined the correction rate of hypernatremia and the amount of fluid required for correction. Therefore, in this study, we will compare the efficacy and safety of rapid intermittent bolus (RIB) and slow continuous infusion (SCI) of electrolyte-free solution in hypernatremia treatment. Methods This is a prospective, investigator-initiated, multicenter, open-label, randomized controlled study with two experimental groups. A total of 166 participants with severe hypernatremia will be enrolled and divided into two randomized groups; both the RIB and SCI groups will be managed with electrolyte-free water. We plan to infuse the same amount of fluid to both groups, for 1 hour in the RIB group and continuously in the SCI group. The primary outcome is a rapid decrease in serum sodium levels within 24 hours. The secondary outcomes will further compare the efficacy and safety of the two treatment protocols. Conclusion This is the first randomized controlled trial to evaluate the efficacy and safety of RIB correction compared with SCI in adult patients with severe hypernatremia

Veratri Nigri Rhizoma et Radix (<i>Veratrum nigrum</i>L.) and Its Constituent Jervine Prevent Adipogenesis via Activation of the LKB1-AMPK<i>α</i>-ACC Axis<i>In Vivo</i>and<i>In Vitro</i>

This study was performed in order to investigate the antiobese effects of the ethanolic extract of Veratri Nigri Rhizoma et Radix (VN), a herb with limited usage, due to its toxicology. An HPLC analysis identified jervine as a constituent of VN. By an Oil Red O assay and a Real-Time RT-PCR assay, VN showed higher antiadipogenic effects than jervine. In high-fat diet- (HFD-) induced obese C57BL/6J mice, VN administration suppressed body weight gain. The levels of peroxisome proliferator-activated receptor gamma (PPARγ), CCAAT-enhancer-binding protein alpha (C/EBPα), adipocyte fatty-acid-binding protein (aP2), adiponectin, resistin, and LIPIN1 were suppressed by VN, while SIRT1 was upregulated. Furthermore, VN activated phosphorylation of the liver kinase B1- (LKB1-) AMP-activated protein kinase alpha- (AMPKα-) acetyl CoA carboxylase (ACC) axis. Further investigation of cotreatment of VN with the AMPK agonist AICAR or AMPK inhibitor Compound C showed that VN can activate the phosphorylation of AMPKαin compensation to the inhibition of Compound C. In conclusion, VN shows antiobesity effects in HFD-induced obese C57BL/6J mice. In 3T3-L1 adipocytes, VN has antiadipogenic features, which is due to activating the LKB1-AMPKα-ACC axis. These results suggest that VN has a potential benefit in preventing obesity.</jats:p

Comparison of serum protein profiles between major depressive disorder and bipolar disorder

Major depressive disorder and bipolar disorder are prevalent and debilitating psychiatric disorders that are difficult to distinguish, as their diagnosis is based on behavioural observations and subjective symptoms. Quantitative protein profile analysis might help to objectively distinguish between these disorders and increase our understanding of their pathophysiology. Thus, this study was conducted to compare the peripheral protein profiles between the two disorders. Serum samples were collected from 18 subjects with major depressive disorder and 15 subjects with bipolar disorder. After depleting abundant proteins, liquid chromatography-tandem mass spectrometry (LC-MS/MS) and label-free quantification were performed. Data-dependent acquisition data were statistically analysed from the samples of 15 subjects with major depressive disorder and 10 subjects with bipolar disorder who were psychotropic drug-free. Two-sided t-tests were performed for pairwise comparisons of proteomes to detect differentially-expressed proteins (DEPs). Ingenuity Pathway Analysis of canonical pathways, disease and functions, and protein networks based on these DEPs was further conducted. Fourteen DEPs were significant between subjects with major depressive disorder and those with bipolar disorder. Ras-related protein Rab-7a (t = 5.975, p= 4.3 × 10− 6) and Rho-associated protein kinase 2 (t = 4.782, p= 8.0 × 10− 5) were significantly overexpressed in subjects with major depressive disorder and Exportin-7 (t = -4.520, p= 1.5 × 10− 4) was significantly overexpressed in subjects with bipolar disorder after considering multiple comparisons. Bioinformatics analysis showed that cellular functions and inflammation/immune pathways were significantly different. Ras-related protein Rab-7a, Rho-associated protein kinase 2, and Exportin-7 were identified as potential peripheral protein candidates to distinguish major depressive disorder and bipolar disorder. Further large sample studies with longitudinal designs and validation processes are warranted.This study was supported by a grant of the Korea Health Technology R&D Project through the Korea Health Industry Development Institute (KHIDI), funded by the Ministry of Health & Welfare, Republic of Korea (grant number: HI17C0870), and a grant from the Ministry of Science, ICT, and Future Planning, Republic of Korea (grant number: NRF-2019M3C7A1030625). The funding body had no involvement in study design planning, data collection, analysis, interpretation of data in writing the manuscript