Structure and dynamics of supercooled SPC/E water confined in silica nanopores and equilibrium glassy films: a two-system study, The

2019 Spring.Includes bibliographical references.Supercooled liquids and glasses is still an area of active research. Despite the wide use of glass in society today, the underlying physics of this phase of matter still contains mysteries. This thesis will examine two different systems of supercooled liquids via molecular simulation and investigate the two systems' structure and dynamics. We first study the temperature dependence of the structure and dynamics of supercooled water confined in hydrophilic silica nanopores. In particular, we focus on the self-intermediate scattering functions. We simulate this system using the SPC/E model of water. These water molecules are confined in model MCM-41 nanopores with radii of 20, 30, and 40 Å. The structure of the water within the pores is first examined and it is found that water molecules form layers near the wall of the pores. However, in the center of the pores, the density is relatively uniform. Using this fact, the pore is divided into two regions: the core and the shell regions. The dynamics of the water molecules that start in each region are then compared. We measure the mean squared displacements and the self-intermediate scattering functions for these two regions. These measurements allows for connection with quasi-elastic neutron scattering experiments. The dependence of the self-intermediate scattering function on direction and magnitude of the wavevector is examined, as well as the function's dependence on proximity to the pore surface. In addition, the rotational-translational decoupling is measured, and it is found that the decoupling is weakly temperature dependent. The second system studied is an equilibrium glassy film deposited onto a substrate in a manner akin to vapor deposition. Glasses created in this manner can have higher kinetic stabilities and different thermodynamic properties than glasses prepared by liquid cooling. This is due to the enhanced mobility of particles at the surface of the film, which allows the particles to find lower potential energy states.Supercooled liquids and glasses is still an area of active research. Despite the wide use of glass in society today, the underlying physics of this phase of matter still contains mysteries. This thesis will examine two different systems of supercooled liquids via molecular simulation and investigate the two systems' structure and dynamics. We first study the temperature dependence of the structure and dynamics of supercooled water confined in hydrophilic silica nanopores. In particular, we focus on the self-intermediate scattering functions. We simulate this system using the SPC/E model of water. These water molecules are confined in model MCM-41 nanopores with radii of 20, 30, and 40 Å. The structure of the water within the pores is first examined and it is found that water molecules form layers near the wall of the pores. However, in the center of the pores, the density is relatively uniform. Using this fact, the pore is divided into two regions: the core and the shell regions. The dynamics of the water molecules that start in each region are then compared. We measure the mean squared displacements and the self-intermediate scattering functions for these two regions. These measurements allows for connection with quasi-elastic neutron scattering experiments. The dependence of the self-intermediate scattering function on direction and magnitude of the wavevector is examined, as well as the function's dependence on proximity to the pore surface. In addition, the rotational-translational decoupling is measured, and it is found that the decoupling is weakly temperature dependent. The second system studied is an equilibrium glassy film deposited onto a substrate in a manner akin to vapor deposition. Glasses created in this manner can have higher kinetic stabilities and different thermodynamic properties than glasses prepared by liquid cooling. This is due to the enhanced mobility of particles at the surface of the film, which allows the particles to find lower potential energy states.We study the temperature dependence of the average and single particle dynamics for particles that start at the surface of the film and for those particles that start in the bulk of the film. First, we examine the average dynamics by calculating the self-intermediate scattering functions and their relaxation times for particles that start in the surface or the bulk region. Then, we calculate the probability of the logarithm of single particle displacements for particles starting in the surface and bulk regions. We find that, in both regions, the distribution of single particle displacements indicate subpopulations of fast and slow particles. This is indicative of heterogeneous dynamics. We also find that the single particle dynamics of particles on the surface mirror particles in the bulk. However, the mirrored dynamics occur several orders of magnitude faster for particles on the surface than for those in the bulk

Serum periostin levels in early in pregnancy are significantly altered in women with miscarriage

Background: Miscarriage is a common complication in pregnancy and there is still a lack of biomarkers usable in asymptomatic patients before the event occurs. Periostin (PER), whose levels rise particularly during injury or inflammation, has been shown to play an important local role in implantation and early embryonic development. As PER has been described as a biomarker in various medical conditions we intended to evaluate if changes in PER serum levels may help to identify women at risk for spontaneous abortion in the first trimester. Methods: Women between 18 and 42 years without confounding comorbidities who conceived by IVF/ICSI and ovarian hyperstimulation were analysed in the study after informed consent. Maternal serum samples from 41 patients were assessed at the time of pregnancy testing (PT) and the following first ultrasound checkup (US). Patients were subsequently divided in two groups: (1) patients with subsequent miscarriage in the first trimester (n = 18) and (2) patients with ongoing pregnancy (n = 23), allowing for statistical analysis and investigating the change of PER levels per individual. PER levels were measured using enzyme-linked immunosorbent assay. Statistical analysis was performed using the Fisher exact and Student’s t test. p ≤ 0.05 was considered to be significant. Results: There was no significant difference concerning possible confounders between the two groups. We did not find any significant difference in PER levels at the time point of PT or US. By investigating the interindividual changes of PER between the two time points however, we observed that patients with a following miscarriage showed increasing levels of PER at the time point of PT compared to US in contrast to patients with an ongoing pregnancy who demonstrated a decrease in PER levels. These alterations were significant in the absolute as well as in the relative comparison. Conclusion: The relative expression of PER between PT and US is significantly altered in asymptomatic women with subsequent miscarriage compared to women with ongoing pregnancy. Therefore systemic PER levels might represent a potential promising biomarker for the assessment of pregnancy outcome. Trial registration Not applicable

SRAM-Based FPGA Systems for Safety-Critical Applications: A Survey on Design Standards and Proposed Methodologies

As the ASIC design cost becomes affordable only for very large-scale productions, the FPGA technology is currently becoming the leading technology for those applications that require a small-scale production. FPGAs can be considered as a technology crossing between hardware and software. Only a small-number of standards for the design of safety-critical systems give guidelines and recommendations that take the peculiarities of the FPGA technology into consideration. The main contribution of this paper is an overview of the existing design standards that regulate the design and verification of FPGA-based systems in safety-critical application fields. Moreover, the paper proposes a survey of significant published research proposals and existing industrial guidelines about the topic, and collects and reports about some lessons learned from industrial and research projects involving the use of FPGA devices

A Novel Multi-objective Optimisation Algorithm for Routability and Timing Driven Circuit Clustering on FPGAs

Circuit clustering algorithms fit synthesised circuits into FPGA configurable logic blocks (CLBs) efficiently. This fundamental process in FPGA CAD flow directly impacts both effort required and performance achievable in subsequent place-and-route processes. Circuit clustering is limited by hardware constraints of specific target architectures. Hence, better circuit clustering approaches are essential for improving device utilisation whilst at the same time optimising circuit performance parameters such as, e.g., power and delay. In this paper, we present a method based on multi-objective genetic algorithm (MOGA) to facilitate circuit clustering. We address a number of challenges including CLB input bandwidth constraints, improvement of CLB utilisation, minimisation of interconnects between CLBs. Our new approach has been validated using the "Golden 20" MCNC benchmark circuits that are regularly used in FPGA-related literature. The results show that the method proposed in this paper achieves improvements of up to 50% in clustering, routability and timing when compared to state-of-the-art approaches including VPack, T-VPack, RPack, DPack, HDPack, MOPack and iRAC. Key contribution of this work is a flexible EDA flow that can incorporate numerous objectives required to successfully tackle real-world circuit design on FPGA, providing device utilisation at increased design performance

The Radiation Issue in Cardiology: the time for action is now

The "radiation issue" is the need to consider possible deterministic effects (e.g., skin injuries) and long-term cancer risks due to ionizing radiation in the risk-benefit assessment of diagnostic or therapeutic testing. Although there are currently no data showing that high-dose medical studies have actually increased the incidence of cancer, the "linear-no threshold" model in radioprotection assumes that no safe dose exists; all doses add up in determining cancer risks; and the risk increases linearly with increasing radiation dose. The possibility of deterministic effects should also be considered when skin or lens doses may be over the threshold. Cardiologists have a special mission to avoid unjustified or non-optimized use of radiation, since they are responsible for 45% of the entire cumulative effective dose of 3.0 mSv (similar to the radiological risk of 150 chest x-rays) per head per year to the US population from all medical sources except radiotherapy. In addition, interventional cardiologists have an exposure per head per year two to three times higher than that of radiologists. The most active and experienced interventional cardiologists in high volume cath labs have an annual exposure equivalent to around 5 mSv per head and a professional lifetime attributable to excess cancer risk on the order of magnitude of 1 in 100. Cardiologists are the contemporary radiologists but sometimes imperfectly aware of the radiological dose of the examination they prescribe or practice, which can range from the equivalent of 1-60 mSv around a reference dose average of 10-15 mSv for a percutaneous coronary intervention, a cardiac radiofrequency ablation, a multi-detector coronary angiography, or a myocardial perfusion imaging scintigraphy. A good cardiologist cannot be afraid of life-saving radiation, but must be afraid of radiation unawareness and negligence