Detection of X-Ray Doses with Color-Changing Hackmanites: Mechanism and Application

Hackmanites, a variety of sodalite with the general formula Na$_{8}$Al$_{6}$Si$_{6}$O$_{24}$(Cl,S)$_{2}$, are a family of nature-based smart materials having the ability for reversible photochromism upon UV or X-ray exposure. Being nontoxic, cheap, and durable, hackmanite would be an optimal material for the visual detection of the presence of X-rays in simple portable systems. However, its X-ray-induced coloring abilities are so far known only qualitatively. In this work, a combination of experimental and computational methods is used to reveal the mechanism of X-ray-induced color changing in these materials. Finally, their use is demonstrated both in color intensity-based X-ray dosimetry and photochromic X-ray imaging

Detection of X-Ray Doses with Color-Changing Hackmanites: Mechanism and Application

Hackmanites, a variety of sodalite with the general formula Na8Al6Si6O24(Cl,S)(2), are a family of nature-based smart materials having the ability for reversible photochromism upon UV or X-ray exposure. Being nontoxic, cheap, and durable, hackmanite would be an optimal material for the visual detection of the presence of X-rays in simple portable systems. However, its X-ray-induced coloring abilities are so far known only qualitatively. In this work, a combination of experimental and computational methods is used to reveal the mechanism of X-ray-induced color changing in these materials. Finally, their use is demonstrated both in color intensity-based X-ray dosimetry and photochromic X-ray imaging

OPTIMADE, an API for exchanging materials data

: The Open Databases Integration for Materials Design (OPTIMADE) consortium has designed a universal application programming interface (API) to make materials databases accessible and interoperable. We outline the first stable release of the specification, v1.0, which is already supported by many leading databases and several software packages. We illustrate the advantages of the OPTIMADE API through worked examples on each of the public materials databases that support the full API specification

OPTIMADE, an API for exchanging materials data.

The Open Databases Integration for Materials Design (OPTIMADE) consortium has designed a universal application programming interface (API) to make materials databases accessible and interoperable. We outline the first stable release of the specification, v1.0, which is already supported by many leading databases and several software packages. We illustrate the advantages of the OPTIMADE API through worked examples on each of the public materials databases that support the full API specification

Genome-wide association for milk production and lactation curve parameters in Holstein dairy cows

The aim of this study was to identify genomic regions associated with 305-day milk yield and lactation curve parameters on primiparous (n = 9,910) and multiparous (n = 11,158) Holstein cows. The SNP solutions were estimated using a weighted single-step genomic BLUP approach and imputed high-density panel (777k) genotypes. The proportion of genetic variance explained by windows of 50 consecutive SNP (with an average of 165 Kb) was calculated, and regions that accounted for more than 0.50% of the variance were used to search for candidate genes. Estimated heritabilities were 0.37, 0.34, 0.17, 0.12, 0.30 and 0.19, respectively, for 305-day milk yield, peak yield, peak time, ramp, scale and decay for primiparous cows. Genetic correlations of 305-day milk yield with peak yield, peak time, ramp, scale and decay in primiparous cows were 0.99, 0.63, 0.20, 0.97 and -0.52, respectively. The results identified three windows on BTA14 associated with 305-day milk yield and the parameters of lactation curve in primi- and multiparous cows. Previously proposed candidate genes for milk yield supported by this work include GRINA, CYHR1, FOXH1, TONSL, PPP1R16A, ARHGAP39, MAF1, OPLAH and MROH1, whereas newly identified candidate genes are MIR2308, ZNF7, ZNF34, SLURP1, MAFA and KIFC2 (BTA14). The protein lipidation biological process term, which plays a key role in controlling protein localization and function, was identified as the most important term enriched by the identified genes

Expert-based development of a generic HACCP-based risk management system to prevent critical negative energy balance in dairy herds

The objective of this study was to develop a generic risk management system based on the Hazard Analysis and Critical Control Point (HACCP) principles for the prevention of critical negative energy balance (NEB) in dairy herds using an expert panel approach. In addition, we discuss the advantages and limitations of the system in terms of implementation in the individual dairy herd. For the expert panel, we invited 30 researchers and advisors with expertise in the field of dairy cow feeding and/or health management from eight European regions. They were invited to a Delphi-based set-up that included three inter-correlated questionnaires in which they were asked to suggest risk factors for critical NEB and to score these based on 'effect' and 'probability'. Finally, the experts were asked to suggest critical control points (CCPs) specified by alarm values, monitoring frequency and corrective actions related to the most relevant risk factors in an operational farm setting. A total of 12 experts (40 %) completed all three questionnaires. Of these 12 experts, seven were researchers and five were advisors and in total they represented seven out of the eight European regions addressed in the questionnaire study. When asking for suggestions on risk factors and CCPs, these were formulated as 'open questions', and the experts' suggestions were numerous and overlapping. The suggestions were merged via a process of linguistic editing in order to eliminate doublets. The editing process revealed that the experts provided a total of 34 CCPs for the 11 risk factors they scored as most important. The consensus among experts was relatively high when scoring the most important risk factors, while there were more diverse suggestions of CCPs with specification of alarm values and corrective actions. We therefore concluded that the expert panel approach only partly succeeded in developing a generic HACCP for critical NEB in dairy cows. We recommend that the output of this paper is used to inform key areas for implementation on the individual dairy farm by local farm teams including farmers and their advisors, who together can conduct herd-specific risk factor profiling, organise the ongoing monitoring of herd-specific CCPs, as well as implement corrective actions when CCP alarm values are exceeded

Modélisation des propriétés spectroscopiques de matériaux ténébrescents

Naturally tenebrescent (reversibly photochromic) materials have been known from geologists since the 1970's but were investigated seriously only recently. The adaptability of these materials, along with their high stability and good reversibility of the photochromism make them of great interest. The aluminosilicate sodalite (Na8Al6Si6O24Cl2) is one of them, with the assessed mechanism being a reversible photoinduced electron transfer from an impurity to a chloride vacancy, leading to the formation of a trapped electron in a crystal box. This trapped electron, called F-center, has quantified levels and absorbs in the visible light. The aim of this work is to develop a methodology based on quantum chemistry to confirm and get more insights on the mechanism at stake. We first designed a simulation protocol to investigate the spectroscopic properties of point defects in sodalite minerals, using Time Dependent Density Functional Theory (TD-DFT). We highlighted the influence of the close environment and the vibronic coupling in these spectra, but also very interestingly the influence of the nature of the defect on the choice of some parameters in the methodology, such as the functional. The methodology was then successfully applied on other aluminosilicate materials, and other type of defects leading to a deeper understanding of these minerals. Then, by adapting the methodology, the photoinduced charge was investigated to understand both the mechanism of the F-center formation and the process of bleaching. These last calculations, performed both at the TD-DFT and post-HF levels, provide paramount information for future development of, among others, specific wavelength sensors.Les matériaux naturels ténébrescents (photochromisme réversible), sont connus des géologues depuis les années 1970 mais ont été étudiés plus attentivement seulement récemment. Leur grande adaptabilité, ainsi que leur stabilité et la bonne réversibilité du photochromisme leur confèrent un grand intérêt. La sodalite (Na8Al6Si6O24Cl2) en est un exemple, et le mécanisme supposé consiste en un transfert photo-induit réversible d’un électron depuis une impureté vers une lacune de chlore, menant à la formation d’un électron piégé dans une boîte cristalline. Cet électron piégé, appelé F-center, a des niveaux quantifiés d’énergie et absorbe dans le domaine du visible. L’objectif de ce travail est de développer une méthode basée sur les outils de la chimie quantique afin de confirmer et d’étudier plus profondément le mécanisme en jeu. Dans un premier temps, nous avons développé un protocole pour simuler les spectres d’absorption ou de fluorescence de défauts ponctuels au sein du matériau sodalite, en utilisant la théorie de la fonctionnelle de la densité dépendante du temps (TD-DFT). Cela a permis de mettre en évidence l’influence de l’environnement proche et du couplage vibronique dans ces spectres, mais aussi, de manière très intéressante, l’influence de la nature du défaut sur le choix de certains paramètres tels que la fonctionnelle. Le protocole a ensuite été appliqué avec succès à l’étude d’autres aluminosilicates, ou d’autres types de défauts, amenant à une compréhension plus complète de ces matériaux. Dans un second temps, en adaptant la méthode, le transfert de charge photo-induit a été simulé pour comprendre à la fois le mécanisme de formation du F-center et le processus de blanchiment. Ces derniers calculs, utilisant la TD-DFT ou des méthodes post Hartree-Fock, ont apporté des éléments de compréhension importants pouvant mener au développement de nouveaux systèmes photochromiques artificiels

Modélisation des propriétés spectroscopiques de matériaux ténébrescents

Les matériaux naturels ténébrescents (photochromisme réversible), sont connus des géologues depuis les années 1970 mais ont été étudiés plus attentivement seulement récemment. Leur grande adaptabilité, ainsi que leur stabilité et la bonne réversibilité du photochromisme leur confèrent un grand intérêt. La sodalite (Na8Al6Si6O24Cl2) en est un exemple, et le mécanisme supposé consiste en un transfert photo-induit réversible d’un électron depuis une impureté vers une lacune de chlore, menant à la formation d’un électron piégé dans une boîte cristalline. Cet électron piégé, appelé F-center, a des niveaux quantifiés d’énergie et absorbe dans le domaine du visible. L’objectif de ce travail est de développer une méthode basée sur les outils de la chimie quantique afin de confirmer et d’étudier plus profondément le mécanisme en jeu. Dans un premier temps, nous avons développé un protocole pour simuler les spectres d’absorption ou de fluorescence de défauts ponctuels au sein du matériau sodalite, en utilisant la théorie de la fonctionnelle de la densité dépendante du temps (TD-DFT). Cela a permis de mettre en évidence l’influence de l’environnement proche et du couplage vibronique dans ces spectres, mais aussi, de manière très intéressante, l’influence de la nature du défaut sur le choix de certains paramètres tels que la fonctionnelle. Le protocole a ensuite été appliqué avec succès à l’étude d’autres aluminosilicates, ou d’autres types de défauts, amenant à une compréhension plus complète de ces matériaux. Dans un second temps, en adaptant la méthode, le transfert de charge photo-induit a été simulé pour comprendre à la fois le mécanisme de formation du F-center et le processus de blanchiment. Ces derniers calculs, utilisant la TD-DFT ou des méthodes post Hartree-Fock, ont apporté des éléments de compréhension importants pouvant mener au développement de nouveaux systèmes photochromiques artificiels.Naturally tenebrescent (reversibly photochromic) materials have been known from geologists since the 1970's but were investigated seriously only recently. The adaptability of these materials, along with their high stability and good reversibility of the photochromism make them of great interest. The aluminosilicate sodalite (Na8Al6Si6O24Cl2) is one of them, with the assessed mechanism being a reversible photoinduced electron transfer from an impurity to a chloride vacancy, leading to the formation of a trapped electron in a crystal box. This trapped electron, called F-center, has quantified levels and absorbs in the visible light. The aim of this work is to develop a methodology based on quantum chemistry to confirm and get more insights on the mechanism at stake. We first designed a simulation protocol to investigate the spectroscopic properties of point defects in sodalite minerals, using Time Dependent Density Functional Theory (TD-DFT). We highlighted the influence of the close environment and the vibronic coupling in these spectra, but also very interestingly the influence of the nature of the defect on the choice of some parameters in the methodology, such as the functional. The methodology was then successfully applied on other aluminosilicate materials, and other type of defects leading to a deeper understanding of these minerals. Then, by adapting the methodology, the photoinduced charge was investigated to understand both the mechanism of the F-center formation and the process of bleaching. These last calculations, performed both at the TD-DFT and post-HF levels, provide paramount information for future development of, among others, specific wavelength sensors

Modélisation des propriétés spectroscopiques de matériaux ténébrescents

Naturally tenebrescent (reversibly photochromic) materials have been known from geologists since the 1970's but were investigated seriously only recently. The adaptability of these materials, along with their high stability and good reversibility of the photochromism make them of great interest. The aluminosilicate sodalite (Na8Al6Si6O24Cl2) is one of them, with the assessed mechanism being a reversible photoinduced electron transfer from an impurity to a chloride vacancy, leading to the formation of a trapped electron in a crystal box. This trapped electron, called F-center, has quantified levels and absorbs in the visible light. The aim of this work is to develop a methodology based on quantum chemistry to confirm and get more insights on the mechanism at stake. We first designed a simulation protocol to investigate the spectroscopic properties of point defects in sodalite minerals, using Time Dependent Density Functional Theory (TD-DFT). We highlighted the influence of the close environment and the vibronic coupling in these spectra, but also very interestingly the influence of the nature of the defect on the choice of some parameters in the methodology, such as the functional. The methodology was then successfully applied on other aluminosilicate materials, and other type of defects leading to a deeper understanding of these minerals. Then, by adapting the methodology, the photoinduced charge was investigated to understand both the mechanism of the F-center formation and the process of bleaching. These last calculations, performed both at the TD-DFT and post-HF levels, provide paramount information for future development of, among others, specific wavelength sensors.Les matériaux naturels ténébrescents (photochromisme réversible), sont connus des géologues depuis les années 1970 mais ont été étudiés plus attentivement seulement récemment. Leur grande adaptabilité, ainsi que leur stabilité et la bonne réversibilité du photochromisme leur confèrent un grand intérêt. La sodalite (Na8Al6Si6O24Cl2) en est un exemple, et le mécanisme supposé consiste en un transfert photo-induit réversible d’un électron depuis une impureté vers une lacune de chlore, menant à la formation d’un électron piégé dans une boîte cristalline. Cet électron piégé, appelé F-center, a des niveaux quantifiés d’énergie et absorbe dans le domaine du visible. L’objectif de ce travail est de développer une méthode basée sur les outils de la chimie quantique afin de confirmer et d’étudier plus profondément le mécanisme en jeu. Dans un premier temps, nous avons développé un protocole pour simuler les spectres d’absorption ou de fluorescence de défauts ponctuels au sein du matériau sodalite, en utilisant la théorie de la fonctionnelle de la densité dépendante du temps (TD-DFT). Cela a permis de mettre en évidence l’influence de l’environnement proche et du couplage vibronique dans ces spectres, mais aussi, de manière très intéressante, l’influence de la nature du défaut sur le choix de certains paramètres tels que la fonctionnelle. Le protocole a ensuite été appliqué avec succès à l’étude d’autres aluminosilicates, ou d’autres types de défauts, amenant à une compréhension plus complète de ces matériaux. Dans un second temps, en adaptant la méthode, le transfert de charge photo-induit a été simulé pour comprendre à la fois le mécanisme de formation du F-center et le processus de blanchiment. Ces derniers calculs, utilisant la TD-DFT ou des méthodes post Hartree-Fock, ont apporté des éléments de compréhension importants pouvant mener au développement de nouveaux systèmes photochromiques artificiels

Ingénierie du photochromisme des aluminosilicates par chimie quantique

Sodalite-based photochromic minerals represent a potentially new family of inorganic photochromes. It was previously proven that the change in the color of these minerals is based on a photo-induced electron transfer from a sulfur-based impurity to a chlorine vacancy, leading to the formation of a trapped electron. In parallel, several groups have shown that it is possible to artificially synthesize these minerals and to tune the chemical composition from the native one (Na8[AlSiO4]6Cl2). In this study, we use an assessed quantum chemical method (based on periodic DFT calculations and TD-DFT calculations on an embedded cluster) to predict the influence of the chemical modification of sodalite on the photochromic properties of the material considering the general composition C8[ABO4]6X2 (A = Si, Ge; B = Al, Ga; C = Na, K; X = Cl, Br, I). The aim of this work is to pave the way for the design of artificial sodalites for specific applications