Dynamic Solvent Models and Exploring the Parameter Space of Hydrogen Fluoride, Hafnium, and Zirconium

Solvation is the interaction of solute and solvent. Every biological interaction hap- pens in a solvent. Most technical procedures occur within solvents and geological processes are too mediated by their solvents. Understanding these effects of solva- tion is therefore critical for the understanding of biology, technology, and geology. While static properties of solvation shells, like coordination numbers and radial dis- tribution functions, are well understood, the dynamic properties of these open sys- tems are rarely studied. Furthermore, an interesting solvation-based phenomenon is the separation of the geochemical twins Zirconium and Hafnium in fluoride-bearing media. In this work, I present a method for evaluating Markov models of solvation shells and investigate ways of combining the solvent models with solute models. Moreover, I attempt to find a suitable two-site and three-site model of hydrogen flu- oride, specialized for its interaction with metal ions. By simulating aqueous and pure HF for several combinations of q, σF , and ϵF and evaluating density, peaks of radial distribution functions as well the solvation free energy of NaF in HF, I hoped to find a suitable model. A three-site model for HF is parameterized by recreating the electrostatic potential of HF with a classical force field, focusing on the location of maximum potential which takes a conical shape around the tip of the ellipsoid and is not located at the poles. A new method is presented which allows the automatic detection of coordination polyhedra based on reference structures and Steinhardt-order parameters. The Lennard-Jones parameter space for tetravalent cations is explored and analyzed in terms of static solvation shell quantities. Finally, the thermal contraction of the solvation shells of Zr4+ and Hf4+ in 1 M HF was investigated using classical MD simulations. The Markov models of solvation shells indicated that solvent dynamics couple close to the solute. Additive combined models yielded slightly higher timescales compared to their individual components. The opposite is true for the multiplicative models which performed just as well or even worse than their components. The parameterization of HF, for the two-site model, yielded two parameter combi- nations that could reproduce three of the five target quantities, the relevant peaks of the F-H and H-H radial distribution functions, as well as the solvation free energy of NaF in HF. After choosing a topology for the three-site model, the Lennard-Jones parameter scans were unable to yield stable simulations of aqueous HF. The project was therefore discontinued and I settled for a recently published HF model. The parameterization of metal cations yielded a very robust result. Static solvation shell properties exist on continuous regions of similar value in the parameter space. These regions appear as a diagonal lines in the log(ϵ M ) − σM parameter space. This behavior is also observed in the coordination polyhedra found by the novel method. The thermal contractions of solvation shells of tetravalent cations could be observed for the four ionic ligands. The contractions are a result of water molecules increas- ing their distance to the central cation. Their missing repulsive Coulomb interaction allows the ionic ligands to move in closer to the central cation, thus causing the thermal contraction. Furthermore, we observed a two-state system for the solvation shells at high temperatures which consists of octahedral and tetrahedral solvation shells interchanging each other. The herein presented results offer new methods for analyzing solvation shells. Firstly by constructing Markov models of these open systems to study their dynamics. Secondly, by automatically determining the coor- dination polyhedron, which is essentially an analysis of the angular distribution of solvent molecules in the solvation shell. The parameterization attempts of HF depict the difficulty of finding parameter com- binations that match all fitting targets, albeit the searched parameter space was rather small. The parameter space for tetravalent cations shows an extremely robust result which can yield the basis for future parameterization attempts. Finally, the peculiar thermal contractions could be explained through classical MD simulations. This shows the power of this method for studying hard ionic systems

Phylogenetic analysis of cyrtocrinid crinoids and its influence on traditional classifications

The cyrtocrinids are a group of mostly Mesozoic articulated crinoids, with rare Cenozoic forms and only two extant taxa. A careful analysis of previous studies indicates that the systematic arrangement of cyrtocrinids is very weak and unsatisfactory for several reasons. In particular, most of the original descriptions and diagnosis date from the past century and are logically influenced by a classical typological philosophy. Not being based on phylogeny, the currently accepted groups for cyrtocrinids must be putatively regarded as “artificial”. In addition, an inappropriate use of characters has been used, typically considered as diagnostic in other groups of crinoids but only marginally applicable to cyrtocrinids (the latter differently characterized for several highly distinctive and autapomorphic characters). In order to mitigate these problems and to arrive at the definition of characters and clades based on unambiguous synapomorphies, we present in this paper a preliminary and exploratory phylogenetic analysis based on parsimony of cyrtocrinids. The obtained topology showed how the traditionally recognized groups prove to be highly paraphyletic and polyphyletic, indicating the need for a complete revision of cyrtocrinids taxonomy, based on phylogeny. The gap-weighting method used for codifying morphometric continuous character, has proved to be a powerful tool to obtain well-resolved and consistent cladograms, even with a limited number of characters

Success rate of surface-treated and non-treated orthodontic miniscrews as anchorage reinforcement in the lower arch for the Herbst appliance: A single-centre, randomised split-mouth clinical trial

Background Surface treatment of miniscrews was implemented to determine whether its application increased bone-to-surface contact and enhanced the interlock between the device and the surrounding bone. Objectives To compare the success rate of surface-treated and non-treated orthodontic miniscrews used as reinforcement of anchorage during treatment with the Herbst appliance. Trial design Split-mouth design with an allocation ratio of 1:1. Methods Eligibility criteria to enrol patients were skeletal and dental class II patients with a retrusive chin, use of the Herbst appliance to correct malocclusion, need for skeletal anchorage using a miniscrew both in the left and right side of the mouth, absence of systemic diseases, absence of using drugs that alter bone metabolism, and good oral hygiene. Patients received self-drilling miniscrews without surface treatment and with surface treatment. Both types presented a 1.4 or 1.2 mm diameter. Miniscrews were inserted between the first molar and second premolars or between the two premolars. The force applied to the screws was an elastic chain from the head of the miniscrews to a direct button applied on the canines. The success rate of each type of miniscrew was considered the primary outcome, and the association of success with demographical, clinical, and geometrical characteristics was investigated. Differences were tested by the generalised linear mixed effects model for the split-mouth design. Differences with a P-value < 0.05 were selected as significant. Randomisation A randomisation list was created for the mouth side assignment. Blinding The study was single blinded with regard to the statistical analysis. Results Thirty-nine miniscrews of the non-treated type and 39 miniscrews of the surface-treated type were inserted in 39 patients (23 female and 16 male, mean age: 15.55 +/- 7.91) recruited between March 2018 and December 2020 with a split-mouth study design. The mean therapy duration was 9.3 months (SD = 1.31). No differences in failure rate were observed between miniscrew types. No serious harm was observed. Conclusions The success rate of surface-treated and non-treated miniscrews showed no significant differences. Registration This trial was not registered

refugee camps as an opportunity for promoting alternative development strategies based on carbon credits

Abstract The difficult social issues faced by non-governmental organizations regarding planning, management, and evolution of the refugee camps led to evaluating alternative development strategies. Indeed, innovative technologies could be promoted for sustainably enhancing local economy. The present model suggests the exploitation of high-albedo materials to generate cool oases in hot climate contexts. The benefits derived by this proposal were investigated by simulating the application of high-albedo devices on shelters in Zaatari, then the avoided carbon emissions were quantified, and several scenarios were discussed. In the framework of the Emissions Trading System, the carbon credits, which can be obtained and sold by contributing to the global warming mitigation process, are estimated to be around 150,000 tons CO 2-eq . Considering the market tendencies presented during the COP21 in Paris, the intervention is demonstrated to be sustainable in economic and environmental terms. The payback period is estimated in 3 years in the most reliable scenario. The work presents the main results of a wider research that also included consideration about the urban planning of the camps

Evaluating the effect of pupil dilation on spectral-domain optical coherence tomography measurements and their quality score

BACKGROUND: Spectral-domain optical coherence tomography (SD-OCT) provides fast scan speed and high scan resolution improving its diagnostic accuracy. The purpose of this study was to evaluate if SD-OCT measurements and their quality score are influenced by pupil dilation. METHODS: Retinal nerve fiber layer thickness (RNFL), ganglion cell complex (GCC) and optic nerve head (ONH) were measured in one eye of 57 glaucoma patients and 36 healthy subjects using spectral domain optical coherence tomography (SD-OCT) before and after pupil dilation. Comparisons were made between measurements and their quality score pre- and post dilation (Signal Strength Index, SSI). Overall RNFL, average GCC and ONH rim volume were considered in the analysis. RESULTS: No statistically significant differences were found between pre- and post-dilation measurements in both groups (glaucoma: RNFL 80 ± 15 μm vs 80 ± 16 μm, p = 0.87; GCC 81.35 ± 13.4 μm vs 81.10 ± 13.14 μm, p = 0.92; ONH 0.05 ± 0.11 mm(3) vs 0.04 ± 0.07 mm(3), p = 0.74; controls RNFL 99 ± 12 μm vs 98 ± 14 μm, p = 0.70; GCC 92.12 ± 6.7 μm vs 91.54 ± 7.05 μm, p = 0.72; ONH 0.11 ± 0.1 mm(3) vs 0.04 ± 0.07 mm(3), p = 0.36) nor between pre- and post-dilation quality score (glaucoma SSI RNFL 54.3 ± 10.3 vs 51.7 ± 18.1, p = 0.12; SSI GCC 58 ± 9.5 vs 57 ± 8.09, p = 0.55; SSI ONH 48.5 ± 7.6 vs 46.6 ± 7.2, p = 0.16; controls SSI RNFL 57 ± 10.3 vs 54 ± 9.31, p = 0.2; SSI GCC 60.9 ± 8.1 vs 58.8 ± 7.3, p = 0.3; SSI ONH 51.5 ± 8.9 vs 50.4 ± 8.3, p = 0.59). CONCLUSION: Pupil dilation doesn’t affect SD-OCT measurements and their quality score

Levels of plasma homocysteine in pseudoexfoliation glaucoma.

BACKGROUND: To examine levels of serum homocysteine (Hcy), vitamin B12 and folic acid in patients with pseudoexfoliation glaucoma (PEXG), primary open-angle glaucoma (POAG), and healthy control subjects. METHODS: This study included 36 patients with PEXG, 40 with POAG, and 40 age-matched healthy subjects. Fasting plasma Hcy concentrations and levels of serum vitamin B12 and folic acid were measured using competitive chemiluminescent enzyme immunoassay; values exceeding 14 μm/l were considered elevated. RESULTS: Mean plasma Hcy was significantly higher in PEXG (16.55 ± 7.23 μm/l) compared with POAG (13.91 ± 3.61 μm/l) and controls (13.12 ± 5.13 μm/l) (p = 0.03 and p = 0.0007 respectively). There were no statistical differences in serum vitamin B12 and folic acid levels among PEXG, POAG and control subjects (p > 0.05). A moderate, although statistically significant, relationship between Hcy and folic acid levels was found in the PEXG group (R(2) = 0.23, p = 0.003). Hcy levels were found not to be related with folic acid or vitamin B12 in either POAG or control subjects. CONCLUSIONS: In this study, plasma Hcy is significantly higher in PEXG group than the POAG and control groups. Hyper-Hcy might play a role in the pathogenesis of PEXG. Hyper-Hcy may be an independent factor stressing vasculopathy in addition to pseudoexfoliation, so might be a modifiable risk factor for PEXG

Strategies for a Positive Anthropogenic Impact in Postwar Buildings

A significant portion of postwar buildings, typically concentrated in suburban areas, are now difficult assets to manage due to their poor sustainability and limited replacement feasibilities. This paper focuses on strategies to improve their metabolism using energy-saving measures based on optimizing energy needs and integrating internal and external energy sources: a new organizational model for energy management should focus first on saving energy, and then on the possibility of integration into a local energy network. This positively affects the anthropogenic impact and becomes a role model for aggregating buildings not only into a district system, but also into a wider, large-scale energy network. The paper shows a significant case study of actual retrofitting intervention that is examined in order to confirm the theoretical guidelines proposed in the first part of the paper. Moreover, another significant case study, taken from common practice, is illustrated, in which different levels of retrofitting are tested. While taking into account the complexity and fragmentation of private property both in a single building and in the city, some strategies are finally described with the aim of reducing the anthropic impact of the postwar building stock

Modular Lunar Hotel

The aim of this paper is to propose an innovative modular lunar hotel or outpost that can be assembled using the load capacity of future rockets Space X is at present developing and presumably will be opera- tional by 2025. In particular, the design is based on the Space X Starship, that will have the capability to land large and heavy payloads on the Moon. The lunar building is essentially made of four cylindrical modules assembled around one central distribution and service hub. These four modules, intended for housing, have a geodesic dome with large windows to observe the lunar environment surrounding the outpost. The entry point to the base is in the lower part of the central module, which is the only part of the building touching the ground and rests on four adjustable legs. The central module will be used for vertical connections and services as well as for hydroponic laboratories and greenhouses in which to grow the food the settlers will eat. The whole structure will be about 15m high and will be protected from cosmic radiation by a magnetic eld generated by a number of electric cables laid on a spherical structure made of in a table high pressure tubes. The modules can be made of light materials since the protection from radiation is supplied by the magnetic eld, and need only a thermal insulating layer, which can be fairly light. The whole structure can thus be carried from Earth without the need of manufacturing it on site. As an added advantage, large windows can be present, mainly in the a top domes/observatories, which will be the characteristic elements of the installation. The cylindrical modules have a diameter of 6m, suitable to be transported in the cargo hold of the Starship. To reach an height of 15m, they are made in sections and then assembled on site. The modules will be lowered from the hold of the Starship by means of the crane with which each spaceship is equipped. Before starting the assembly of the modules, self-propelled cranes and vehicles will be carried to the Moon so that the construction site of the hotel/outpost can be relatively distant from the landing area. These construction machines will then remain available for other construction projects on the Moon. A total of about 10 launches are expected to be required to carry to the Moon all parts needed to build the facility

A Modular Lunar Hotel

The aim of this paper is to propose an innovative modular lunar hotel/outpost that can be assembled using the load capacity of future rockets Space X is at present developing and presumably will be opera- tional by 2025. In particular, the design is based on the Space X' Starship, that will have the capability to land large and heavy payloads on the Moon. The lunar building is essentially made of four cylindrical modules assembled around one central distribution and service hub. These four modules, intended for housing, have a geodesic dome with large windows to observe the lunar environment surrounding the outpost. The entry point to the base is in the lower part of the central module, which is the only part of the building touching the ground and rests on four adjustable legs. The central module will be used for vertical connections and services as well as for hydroponic laboratories and greenhouses in which to grow the food the settlers will eat. The whole structure will be about 15m high and will be protected from cosmic radiation by a magnetic eld generated by a number of electric cables laid on a spherical structure made of in atable high pressure tubes. The modules can be made of light material since the protection form radiation is supplied by the magnetic eld, and need only a thermal insulating layer, which can be fairly light. The whole structure can thus be carried from Earth without the need of manufacturing it on site. As an added advantage, large windows can be present, mainly in the a top domes/observatories, which will be the characteristic elements of the installation. The cylindrical modules have a diameter of 6m, suitable to be transported in the cargo hold of the Starship. To reach an height of 15m, they are made in sections and then assembled on site. The modules will be lowered from the hold of the Starship by means of the crane with which each spaceship is equipped. Before starting the assembly of the modules, self-propelled cranes and vehicles will be carried to the Moon so that the construction site of the hotel/outpost can be relatively distant from the landing area. These construction machines will then remain available for other construction projects on the Moon. A total of about 10 launches are expected to be required to carry to the Moon all parts needed to build the facility