M. S.

No / We address the problem of recognition and growth of ice nuclei in simulation of supercooled bulk water. Bond orientation order parameters based on the spherical harmonics analysis are shown to be ineffective when applied to ice nucleation. Here we present an alternative method which robustly differentiates between hexagonal and cubic ice forms. The method is based on accumulation of the maximum projection of bond orientations onto a set of predetermined vectors, where different terms can contribute with opposite signs with the result that the irrelevant or incompatible molecular arrangements are damped out. We also introduce an effective cluster size by assigning a quality weight to each molecule in an ice-like cluster. We employ our cluster analysis in Monte Carlo simulation of homogeneous ice formation. Replica-exchange umbrella sampling is used for biasing the growth of the largest cluster and calculating the associated free energy barrier. Our results suggest that the ice formation can be seen as a two-stage process. Initially, short tetrahedrally arranged threads and rings are present; these become correlated and form a diffuse ice-genic network. Later, hydrogen bond arrangements within the amorphous ice-like structure gradually settle down and simultaneously `tune-up¿ nearby water molecules. As a result, a well-shaped ice core emerges and spreads throughout the system. The process is very slow and diverse owing to the rough energetic landscape and sluggish molecular motion in supercooled water, while large configurational fluctuations are needed for crystallization to occur. In the small systems studied so far the highly cooperative molecular rearrangements eventually lead to a relatively fast percolation of the forming ice structure through the periodic boundaries, which inevitably affects the simulation results. / EPSRC

Yes / The focus of the construction industry has shifted towards the development of al-ternative, eco-friendly and green construction materials due to the energy-inefficient and carbon-intensive nature of Portland cement (PC) production and aggregate quarrying. Meanwhile, increased number of repetitive re-pair/renovation/maintenance activities and demolition operations for the end-of-life buildings generate significant amounts of construction and demolition waste (CDW). For the purposes of sustainability and upcycling wastes into high-value-added materials with improved greenness, components from CDW streams can be used in producing geopolymer concretes without using PC and natural aggre-gates, given the rich aluminosiliceous nature of CDW components. The focus of current work is therefore on the analysis of durability of aspects (i.e., drying shrinkage and resistance against sulfate attack, cyclic freezing-thawing, and chlo-ride penetration) of geopolymer concretes made entirely of CDW. Different types of bricks, tile, concrete, and glass were used in mixed form as precursors for ge-opolymerization while different-size grains of waste concrete were used as recy-cled aggregates. As alkali activators, sodium hydroxide, calcium hydroxide and sodium silicate were used. In a companion mixture, CDW-based precursors were replaced with slag and class-F fly ash. Results showed that sulfate and cyclic freeze-thaw exposure did not cause any noticeable weight and compressive strength loss in CDW-based geopolymer concretes, while chloride penetration was found comparable to PC-based concrete. While drying shrinkage was found high in entirely CDW-based geopolymer concrete and resulted in surface mi-crocracks, it was possible to lower the drying shrinkage substantially via substi-tution of CDW-based precursors with fly ash and slag. / The authors also wish to thank the support of Scientific and Technical Research Council (TUBITAK) of Turkey provided under projects: 218M102 and 117M447. / This paper is from the fib Symposium 2023, Building for the future: Durable, Sustainable, Resilient. 5-7 Jun, Istanbul, Turkey.

Studien är utförd åt Freezing Food Småland Öland AB. Syftet med undersökningen var att ge förslag på åtgärder som minskar anläggningens energibehov samt att beräkna återbetalningstid för åtgärder. Genom användningen av simuleringsprogramvara tillsammans med data från praktiska mätningar så testades olika förändringar i anläggningen. Studien resulterade i förslag på en höjning av frysrumstemperaturen och temperaturen i LTB1. Dessa åtgärder höjer anläggningens köldfaktor och minskar energibehovet. Förslag för att få bukt på istillväxten är att isolera av komponenter så som rör och ventiler. Isolering ger en energibesparing och en minskad risk för korrosion. Genom belastningstester framkom det att kompressorerna arbetar ofördelaktigt så förslag på lämpliga driftområden togs fram för att öka verkningsgraden och minska underhållskostnaderna och energibehovet. Anläggningen visade sig vara väl dimensionerad mot transmissionsförluster men att golvvärmen står för en oproportionerligt stor del av förlusterna i förhållande till dess yta. / The study is conducted for Freezing Food Småland Öland AB. The purpose of the study was to propose measures to decrease the facility’s energy demand and to calculate the payback time for these suggestions. By means of using simulation software along with data from practical measurements different configurations in the facility were tested. The study resulted in suggestions consisting of an increase of the temperature in the freezing room and the temperature in LTB1.Those suggestions increases the facilities COP and decreases the energy consumption. Proposals to curb the ice growth are the insulation of components such as pipes and valves. Insulation results in a small decrease in energy demand but greatly increases the accessibility and also decreases the risk of corrosion. Through load tests conducted on the compressors it showed that the compressors were not driven in the optimal load range, suggestions were made for operation in a more favourable load range. Thus increasing the efficiency and cutting the maintenance costs. From the results it is shown that the facility is well built and dimensioned against thermal transmission. Though it turned out that the floor heating accounts for a disproportionate amount of the thermal transmission.

La peur est ce qui permet de réagir à un stimulus aversif par une réponse de défense adaptée à la situation. Elle peut être générée par un ensemble de stimuli naturellement aversifs ou par des stimuli ayant acquis une valeur aversive par apprentissage associatif. Cette thèse a pour but d'étudier les caractéristiques et modifications de la réponse de peur à ces deux types de stimuli au cours de l'ontogenèse. Les études présentées ici utilisent un conditionnement de peur à l'odeur chez le rat qui associe une odeur à un stimulus aversif et permet d'induire très rapidement et durablement des mémoires de peur à l'odeur. La réponse de défense peut alors être étudiée à la fois envers l'odeur apprise et envers le stimulus naturellement aversif. Nous montrons en particulier que la réponse de peur à l'odeur apprise présente un décours temporel corrélé à la durée de l'intervalle de temps entre l'odeur et le stimulus aversif, permettant d'affirmer que les animaux mémorisent et estiment le temps, et ce dès les premiers âges étudiés, avant la maturation des structures cérébrales classiquement impliquées dans cette mémoire temporelle. Par ailleurs, nous nous sommes intéressés aux vocalisations ultrasonores émises en réponse au stimulus aversif et à leur modification au cours de l'ontogenèse. Nous avons mis en évidence deux types de vocalisations chez le raton, dont les caractéristiques et critères d'induction laissent présager un rôle différentiel qui reste à explorer. L'ensemble de ces travaux soulignent que, même si les réponses de défense du rat changent au cours du développement, la capacité à produire ces réponses de manière temporellement adaptée est observée dès le plus jeune âge / Fear allows individuals to react to an aversive stimulus by a defense response adapted to the situation. It can be triggered by naturally aversive stimuli or in response to stimuli that acquired an aversive valence through associative learning. This thesis investigated the characteristics and modifications of fear responses to these two types of stimuli throughout ontogeny. The studies presented here used olfactory fear conditioning in rat, in which an odor is paired with an aversive event and allows to rapidly induce long lasting odor fear memories. Defense responses can then be studied both to the learned odor and to the naturally aversive stimulus. We showed in particular that fear response to the learned odor presents a temporal pattern correlated with the duration of the time interval between the odor and the aversive event, showing that rats can learn about time and they do so at the youngest ages studied here, before the maturation of the brain structures classically involved in interval timing. We also studied the ultrasonic vocalizations emitted in response to the aversive stimulus and their changes throughout ontogeny. We described two types of vocalizations in pups that differ in their characteristics and emission context, suggesting they could have different functions, which needs further exploration. These thesis findings highlight that although the rat’s defense responses changes through ontogeny, the ability to produce temporally adapted responses occurs from the youngest age

[pt] Embora diversos modelos animais sejam utilizados para testar e selecionar efeitos de drogas ansiolíticas e ansiogênicas, relativamente poucos estudos têm examinado os efeitos de manipulações farmacológicas em animais geneticamente selecionados para fenótipos comportamentais mais diretamente relacionados a transtornos específicos de ansiedade em humanos. O presente estudo investigou os efeitos de um benzodiazepínico (midazolam) no labirinto em cruz elevado (LCE) em duas linhagens de ratos que vêm sendo selecionadas em nosso laboratório para traços altos (Cariocas Alto- Congelamento, CAC) ou baixos (Cariocas Baixo-Congelamento, CBC) relacionados à ansiedade. Após terem suas respostas de congelamento ao contexto registradas e comparadas, animais da vigésima quarta, vigésima quinta e vigésima sexta gerações dessas duas linhagens de ratos foram expostos ao labirinto em cruz elevado (LCE) sob os efeitos de injeções intraperitoneais (1,0 ml/kg) de veículo-salina (0,9 por cento) ou midazolam nas doses de 0,25, 0,5, 0,75 e 1,0 mg/kg. Quando injetados com salina, animais CAC e CBC apresentaram parâmetros maiores e menores de ansiedade, respectivamente, em comparação a animais-controle selecionados randomicamente. O midazolam aumentou de maneira semelhante a exploração dos braços abertos em todos os grupos, embora esse efeito ansiolítico nos animais CBC tenha ocorrido apenas na dose mais baixa da droga (0,25 mg/kg). Esses resultados indicam que os traços relacionados à ansiedade previamente selecionados para respostas altas ou baixas de congelamento ao contexto também se expressam fenotipicamente em padrões comportamentais de exploração no LCE. A utilidade dessas duas linhas de ratos para modelar transtorno de ansiedade generalizada e selecionar efeitos potencialmente ansiolíticos de novas drogas é explorada. / [en] Although several animal models are used to test and screen anxiolytic and anxiogenic-like drug effects, relatively few studies have examined the effects of pharmacological manipulations in genetically selected animals for behavioral phenotypic traits more directly related to specific anxiety disorders in humans. The present study investigated the effects of a benzodiazepine midazolam in the elevated plus-maze (EPM) in two rat lines which have been selectively bred in our laboratory for high (Cariocas High-Freezing, CHF) or low (Cariocas Low-Freezing, CLF) anxiety-like traits. After being their contextual freezing response registered and compared, animals from the 24th, 25th and 26th generations of these two rat lines were exposed to the EPM under the effects of intraperitoneal injections (1.0 ml/kg) of either vehiclesaline (0.9 per cent) or midazolam in the doses of 0.25, 0.5 and 0.75. When injected with saline, CHF and CLF animals showed higher and lower anxiety-like parameters, respectively, as compared to control-animals randomly selected. Midazolam similarly increased open-arm exploration in all groups, although this anxiolytic-like effect in CLF animals only occurred at the lowest drug dose (0.25 mg/kg). These results indicate that the anxiety-like traits previously selected for high or low contextual freezing responses are also phenotypically expressed in behavioral patterns of exploration in the EPM. The usefulness of these two rat lines to model generalized anxiety disorder and screen new putative anxiolytic drug effects is explored.

Les troubles de la marche et le freezing entraînent une invalidité sévère et ont un impact important sur la qualité de vie des patients souffrant de la maladie de Parkinson (MP). Ceci est d'autant plus vrai que ces troubles répondent mal aux traitements actuels, médicamenteux et chirurgicaux. Leurs mécanismes physiopathologiques sont largement incompris. Toutefois, leur résistance aux traitements courants suggère l'extension du processus lésionnel vers des structures non-dopaminergiques concourant au contrôle de la locomotion. L'implication du noyau pédonculopontin (PPN) a été évoquée. L'objectif de cette étude était de mieux comprendre les circuits neuronaux impliqués dans ces troubles, ainsi que leur modulation par les médicaments dopaminergiques et la stimulation du PPN. Les contraintes d'immobilité de la tête, liées à l'utilisation de la technique de tomographie par émission de positons (TEP), excluant la réalisation d'une épreuve effective de marche, la tâche a été effectuée en imagerie mentale. Les mêmes réseaux neuronaux sont en effet activés lors de la réalisation effective et la représentation mentale d'un mouvement, sous réserve que l'imagerie mentale motrice soit réalisée selon une perspective dite kinesthésique. Il était donc nécessaire, au préalable, de vérifier l'aptitude des patients à imager leur marche selon cette modalité. Nos données vont dans ce sens, et montrent qu'il est possible d'améliorer cette capacité à travers une préparation spécifique. De plus, l'utilisation d'un protocole comportemental d'imagerie mentale reposant sur la loi de Fitts a permis de familiariser les patients avec la tâche d'imagerie mentale en amont de la réalisation des examens TEP, mais aussi de vérifier leur engagement dans cette dernière durant les acquisitions cérébrales. Les résultats obtenus à l'issue de l'étude menée en imagerie cérébrale confirment la complexité de la physiopathologie des troubles locomoteurs, et suggèrent notamment différents niveaux d'atteinte, à l'étage cortical, sous cortical, et du tronc cérébral, selon la nature dopa-sensible ou dopa-résistante du trouble concerné. En particulier, la dérégulation frontale semble confirmée. De plus, un dysfonctionnement du tronc cérébral pourrait être lié à l'émergence des troubles de la marche et du freezing. Nous avons également constaté une implication pariétale, mais son rôle compensateur, ou pathologique, reste encore à définir. Le freezing dopa-sensible pourrait en partie refléter l'expression aggravée de la bradykinésie parkinsonienne, étant donné l'efficacité de la lévodopa sur ce symptôme. La stimulation de la région des PPN semble quant à elle restaurer une boucle cortico-cérebello-thalamo-corticale, facilitant le mouvement dans le cas des troubles dopa-résistants. Des investigations complémentaires, sur un échantillon plus large de patients, sont donc nécessaires pour approfondir ces résultats. Une meilleure compréhension de la physiopathologie de ces troubles est en effet indispensable pour le développement de nouvelles thérapeutiques dans le but d'améliorer la prise en charge des patients souffrant de ces troubles invalidants, et ainsi leurs répercussions en termes de santé publique. / Gait disorders, including freezing of gait are frequent and disabling symptoms that lead to severe decrease of the quality of life on patients from Parkinson's disease (PD). This is emphasized by the fact that those difficulties respond poorly to current medical and surgical treatments. The underlying pathophysiology remains largely unknown. However, the resistance to actual treatments suggests the extension of the degenerative process towards non-dopaminergic structures. Involvement of the pedonculopontine nucleus (PPN) has been proposed. The aim of the study was to better understand the neural networks involved in those troubles, as well as their modulation by dopaminergic drugs and PPN stimulation. The constraints related to stillness of the head during Positron Emission Tomography (PET) exclude, necessarily, the realization of an effective gait. This task has been accomplished using mental moor imagery. The same mural networks are, indeed, activated during the actual execution and the mental representation of movement, under the assumption that motor mental imaging is undertaken from a kinesthetic perspective. Thus, it was necessary, preliminarily to this study, to control the ability of patients to imagine themselves walking from a kinesthetic point of view. Our data validate this condition. Moreover, they show that it is possible to improve this ability through a specific training. What is more, the use of a behavioral protocol, based on Fitt's law, helped the patients to familiarize themselves with this approach, before PET acquisitions, but also to control their correct performance during PET scan. The results, which have been obtained in cerebral imaging confirm the complexity of the underlying mechanisms of gait disorders, and suggest notably different levels of deregulation, on a cortical, sub-cortical and brainstem. In particular, frontal deregulation appears to be confirmed. Moreover, a deregulation of the brainstem could be more particularly involved in gait disorders apparition. We have also evidenced parietal implication, but its exact compensatory or pathologic role remains to be determined. Levodopa-responsive freezing seems to be a consequence of worsened parkinsonian bradykinesia. PPN stimulation seems able to restore a functional cortico-cerebello-cortical loop, facilitating movement. Complementarily studies, on a larger selection of patients, are thus necessary to complete those results. A better understanding of pathophysiology is, as a matter of fact, necessary for the development of new therapeutics in order to improve the therapy of patients from those very invalidating troubles, and thus, to reduce their impact on public health.

The standard ASTM C672 de-icer salt scaling resistance test has been found to be overly aggressive to concretes containing slag cement. It was compared to the newly proposed ASTM WK9367 method, based on the Quebec BNQ test, as well as several modifications, including use of an accelerated curing regime developed in Virginia (VADOT). Sixteen concrete mixtures were studied using high-alkali cement, low-alkali cement, grade 100 slag and grade 120 slag with slag contents of 0%, 20%, 35% and 50%. Vinsol resin air-entraining admixture was compared to Micro Air®. Reducing the water cement ratio from 0.42 to 0.38 had the biggest impact on improving scaling resistance of slag concretes. In general, increased slag contents increased scaling regardless of the test method used. The Micro Air® admixture provided a lower air void actor and higher hardened air content compared to Vinsol resin.

The standard ASTM C672 de-icer salt scaling resistance test has been found to be overly aggressive to concretes containing slag cement. It was compared to the newly proposed ASTM WK9367 method, based on the Quebec BNQ test, as well as several modifications, including use of an accelerated curing regime developed in Virginia (VADOT). Sixteen concrete mixtures were studied using high-alkali cement, low-alkali cement, grade 100 slag and grade 120 slag with slag contents of 0%, 20%, 35% and 50%. Vinsol resin air-entraining admixture was compared to Micro Air®. Reducing the water cement ratio from 0.42 to 0.38 had the biggest impact on improving scaling resistance of slag concretes. In general, increased slag contents increased scaling regardless of the test method used. The Micro Air® admixture provided a lower air void actor and higher hardened air content compared to Vinsol resin.

Preparation of biological samples for transmission electron microscopy is not a trivial task. The samples must withstand a vacuum environment present inside a microscope, and it is often necessary to use non-physiological procedures for their processing. These procedures usually involve aldehyde-based fixation, replacing water with alcohol (i.e. dehydration/substitution), and embedding into a resin, which creates support for the subsequent preparation of thin sections that can be placed into the microscope. In the last decade, the method of cryo-fixation (vitrification) using ultra-fast high-pressure freezing followed by freeze substitution and low-temperature resin embedding gained a dominant position in the cell biology research. In this way, a range of biological samples with a thicknesses up to several hundreds of micrometers was successfully vitrified to a state that was closely related to their in vivo structures. The cryo-fixation of isolated biological objects (with a limited thickness up to several micrometers) is possible in a thin layer of vitrified water by plunge freezing at ambient pressure. In combination with electron cryo-microscopy, this method has become the most effective and fundamental principle for the high-resolution studies and image analysis of fully hydrated samples...