Dispositifs électroniques et optiques à base de complexe à transition de spin [Fe(HB(1,2,4-triazol-1-yl)3)2]

L'objectif central de cette thèse est l'exploration des applications potentielles des complexes moléculaires à transition de spin dans les dispositifs électroniques et photoniques. Dans ce but, des films minces cristallins de haute qualité, déposés thermiquement sous vide, du complexe [Fe(HB(tz)3)2] (tz = (1,2,4-triazol-1-yl), présentant une bistabilité robuste à température ambiante, ont été incorporés dans des dispositifs à deux et trois bornes. Des jonctions verticales de grande surface ont été formées par des empilements ITO/[Fe(HB(tz)3)2]/Al. Ces jonctions ont présenté une chute de résistance allant jusqu'à trois ordres de grandeur lors du passage de l'état bas spin à l'état haut spin. Elles ont également révélé une grande résistance à la fatigue lors du stockage (> 1 an) et lors de commutations répétées (>10 000) à l'air ambiant. Le mécanisme de commutation de résistance pourrait être lié au transport de charge intrinsèque au film de complexe à transition de spin. Des jonctions multicouches similaires avec des électrodes magnétiques ont également été fabriquées pour la première fois. Des films de [Fe(HB(tz)3)2] ont été par la suite incorporés dans des transistors organiques à effet de champ. Différentes configurations ont été réalisées (grille inférieure/contact inférieur, grille inférieure/contact supérieur) - dans le but d'utiliser le phénomène de transition de spin pour moduler les propriétés des transistors. Malgré des difficultés considérables pour obtenir des caractérisations reproductibles en fonction de la température, nous avons pu mettre en évidence de modifications de différentes caractéristiques en fonction de la température, qui pourraient être liées à la transition de spin. En parallèle, des cavités multicouches Ag/[Fe(HB(tz)3)2]/Ag de type Fabry-Perot ont également été fabriquées. Ces dispositifs utilisent la commutation remarquable de l'indice de réfraction (n = 0,04 - 0,2) entre les états bas spin et haut spin dans le film [Fe(HB(tz)3)2] pour réaliser la modulation de la résonance de la cavité. Cette possibilité d'ajustement de la longueur d'onde centrale est associée à de faibles pertes d'absorption dans les domaines spectraux du visible et du proche infrarouge, ce qui ouvre la voie au développement des dispositifs photoniques reconfigurables et auto-adaptatives.The central aim of this thesis is the exploration of potential applications of molecular spin crossover complexes in electronic and photonic devices. To this aim vacuum thermal deposited, high quality, crystalline thin films of the complex [Fe(HB(tz)3)2] (tz = (1,2,4-triazol-1-yl), displaying robust, above-room-temperature spin crossover, were incorporated into two- and three-terminal device configurations. Large-area, vertical junctions were formed by ITO/[Fe(HB(tz)3)2]/Al stacks. The junctions exhibited up to three orders of magnitude resistance drop when switching from the low-spin to the high-spin state. They revealed also high resistance to fatigue both on storage (> 1 year) and on repeated switching (>10,000) in ambient air. The resistance switching mechanism could be linked to the intrinsic charge transport in the spin crossover film. Similar multilayer junctions with magnetic electrodes were also fabricated for the first time. [Fe(HB(tz)3)2] films were then incorporated into organic field-effect transistors. Different device configurations were created (bottom gate/bottom contact, bottom gate/top contact) - aiming for the use of the spin crossover phenomenon to modulate the transfer/output characteristics of the transistors. Despite considerable difficulties in achieving reproducible temperature-dependent characterizations, we could evidence changes of the device characteristics, which may be related to the spin crossover phenomenon. In parallel, multilayer Ag/[Fe(HB(tz)3)2]/Ag Fabry-Perot cavities were also fabricated. These devices use the remarkable refractive index switching (Δn = 0.04 - 0.2) between the low-spin and high-spin states in the [Fe(HB(tz)3)2] film to achieve modulation of the cavity resonance. This wavelength tuneability is coupled with low absorption losses in the visible and near infrared spectral ranges, providing scope for reconfigurable and self-adaptive photonics applications

Multilevel Matrix Factor Model

Large-scale matrix data has been widely discovered and continuously studied in various fields recently. Considering the multi-level factor structure and utilizing the matrix structure, we propose a multilevel matrix factor model with both global and local factors. The global factors can affect all matrix times series, whereas the local factors are only allow to affect within each specific matrix time series. The estimation procedures can consistently estimate the factor loadings and determine the number of factors. We establish the asymptotic properties of the estimators. The simulation is presented to illustrate the performance of the proposed estimation method. We utilize the model to analyze eight indicators across 200 stocks from ten distinct industries, demonstrating the empirical utility of our proposed approach.Comment: 47 pages, 22 figure

Efficient non-collinear antiferromagnetic state switching induced by orbital Hall effect in chromium

Recently orbital Hall current has attracted attention as an alternative method to switch the magnetization of ferromagnets. Here we present our findings on electrical switching of antiferromagnetic state in Mn3Sn/Cr, where despite the much smaller spin Hall angle of Cr, the switching current density is comparable to heavy metal based heterostructures. On the other hand, the inverse process, i.e., spin-to-charge conversion in Cr-based heterostructures is much less efficient than the Pt-based equivalents, as manifested in the almost one order of magnitude smaller terahertz emission intensity and spin current induced magnetoresistance in Cr-based structures. These results in combination with the slow decay of terahertz emission against Cr thickness (diffusion length of ~11 nm) suggest that the observed magnetic switching can be attributed to orbital current generation in Cr, followed by efficient conversion to spin current. Our work demonstrates the potential of light metals like Cr as an efficient orbital/spin current source for antiferromagnetic spintronics.Comment: 19 pages, 4 figure

Effects of the Chinese herbal formula San-Huang Gu-Ben Zhi-Ke treatment on stable chronic obstructive pulmonary disease: a randomized, double-blind, placebo-controlled trial

Objective: The aim of this study was to evaluate the efficacy and safety of the Chinese herbal formula San-Huang Gu-Ben Zhi-Ke (SHGBZK) as a treatment for patients with stable chronic obstructive pulmonary disease (COPD) diagnosed with lung-spleen Qi deficiency.Method: A randomized, double-blind, placebo-controlled trial was designed. 98 adults aged between 40 and 80 years with stable COPD diagnosed with lung-spleen Qi deficiency were included. All participants received basic treatment for COPD. Patients in the experimental group took SHGBZK, while the control group took placebo. The primary outcome was the frequency of acute exacerbation. The secondary outcomes were lung function, symptom score, exercise capacity and quality of life.Results: Of 98 patients who underwent randomization, 50 patients in the SHGBZK group and 48 in the placebo group were included in the full analysis set. After 24-week therapy and 28-week follow-up, patients in treatment group had significant improvements in symptom, exercise capacity and quality of life. After Subgroup analysis, the frequency of acute exacerbation in patients with a COPD Assessment Test (CAT) score of at least 10 or a modified Medical Research Council (mMRC) score of at least 2 was significantly lower in the SHGBZK group than in the placebo group. Lung function in patients with frequent exacerbation was significantly higher in the SHGBZK group than in the placebo group. The incidence of adverse events was generally similar in the two groups.Conclusion: SHGBZK had beneficial effects on symptom, exercise capacity and quality of life in stable COPD patients. SHGBZK also had the potential to reduce the frequency of exacerbation and improve lung function in specific groups of COPD patients.Clinical Trial Registration:https://www.chictr.org.cn/showproj.html?proj=26933, identifier ChiCTR180001634

In vivo printing of growth factor-eluting adhesive scaffolds improves wound healing

Acute and chronic wounds affect millions of people around the world, imposing a growing financial burden on patients and hospitals. Despite the application of current wound management strategies, the physiological healing process is disrupted in many cases, resulting in impaired wound healing. Therefore, more efficient and easy-to-use treatment modalities are needed. In this study, we demonstrate the benefit of in vivo printed, growth factor-eluting adhesive scaffolds for the treatment of full-thickness wounds in a porcine model. A custom-made handheld printer is implemented to finely print gelatin-methacryloyl (GelMA) hydrogel containing vascular endothelial growth factor (VEGF) into the wounds. In vitro and in vivo results show that the in situ GelMA crosslinking induces a strong scaffold adhesion and enables printing on curved surfaces of wet tissues, without the need for any sutures. The scaffold is further shown to offer a sustained release of VEGF, enhancing the migration of endothelial cells in vitro. Histological analyses demonstrate that the administration of the VEGF-eluting GelMA scaffolds that remain adherent to the wound bed significantly improves the quality of healing in porcine wounds. The introduced in vivo printing strategy for wound healing applications is translational and convenient to use in any place, such as an operating room, and does not require expensive bioprinters or imaging modalities

CT-based radiomics for predicting radio-chemotherapy response and overall survival in nonsurgical esophageal carcinoma

BackgroundTo predict treatment response and 2 years overall survival (OS) of radio-chemotherapy in patients with esophageal cancer (EC) by radiomics based on the computed tomography (CT) images.MethodsThis study retrospectively collected 171 nonsurgical EC patients treated with radio-chemotherapy from Jan 2010 to Jan 2019. 80 patients were randomly divided into training (n=64) and validation (n=16) cohorts to predict the radiochemotherapy response. The models predicting treatment response were established by Lasso and logistic regression. A total of 156 patients were allocated into the training cohort (n=110), validation cohort (n=23) and test set (n=23) to predict 2-year OS. The Lasso Cox model and Cox proportional hazards model established the models predicting 2-year OS.ResultsTo predict the radiochemotherapy response, WFK as a radiomics feature, and clinical stages and clinical M stages (cM) as clinical features were selected to construct the clinical-radiomics model, achieving 0.78 and 0.75 AUC (area under the curve) in the training and validation sets, respectively. Furthermore, radiomics features called WFI and WGI combined with clinical features (smoking index, pathological types, cM) were the optimal predictors to predict 2-year OS. The AUC values of the clinical-radiomics model were 0.71 and 0.70 in the training set and validation set, respectively.ConclusionsThis study demonstrated that planning CT-based radiomics showed the predictability of the radiochemotherapy response and 2-year OS in nonsurgical esophageal carcinoma. The predictive results prior to treatment have the potential to assist physicians in choosing the optimal therapeutic strategy to prolong overall survival

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Electronic and optical devices integrating thin films of the spin crossover complex [Fe(HB(1,2,4-triazol-1-yl)3)2]

L'objectif central de cette thèse est l'exploration des applications potentielles des complexes moléculaires à transition de spin dans les dispositifs électroniques et photoniques. Dans ce but, des films minces cristallins de haute qualité, déposés thermiquement sous vide, du complexe [Fe(HB(tz)3)2] (tz = (1,2,4-triazol-1-yl), présentant une bistabilité robuste à température ambiante, ont été incorporés dans des dispositifs à deux et trois bornes. Des jonctions verticales de grande surface ont été formées par des empilements ITO/[Fe(HB(tz)3)2]/Al. Ces jonctions ont présenté une chute de résistance allant jusqu'à trois ordres de grandeur lors du passage de l'état bas spin à l'état haut spin. Elles ont également révélé une grande résistance à la fatigue lors du stockage (> 1 an) et lors de commutations répétées (>10 000) à l'air ambiant. Le mécanisme de commutation de résistance pourrait être lié au transport de charge intrinsèque au film de complexe à transition de spin. Des jonctions multicouches similaires avec des électrodes magnétiques ont également été fabriquées pour la première fois. Des films de [Fe(HB(tz)3)2] ont été par la suite incorporés dans des transistors organiques à effet de champ. Différentes configurations ont été réalisées (grille inférieure/contact inférieur, grille inférieure/contact supérieur) - dans le but d'utiliser le phénomène de transition de spin pour moduler les propriétés des transistors. Malgré des difficultés considérables pour obtenir des caractérisations reproductibles en fonction de la température, nous avons pu mettre en évidence de modifications de différentes caractéristiques en fonction de la température, qui pourraient être liées à la transition de spin. En parallèle, des cavités multicouches Ag/[Fe(HB(tz)3)2]/Ag de type Fabry-Perot ont également été fabriquées. Ces dispositifs utilisent la commutation remarquable de l'indice de réfraction (n = 0,04 - 0,2) entre les états bas spin et haut spin dans le film [Fe(HB(tz)3)2] pour réaliser la modulation de la résonance de la cavité. Cette possibilité d'ajustement de la longueur d'onde centrale est associée à de faibles pertes d'absorption dans les domaines spectraux du visible et du proche infrarouge, ce qui ouvre la voie au développement des dispositifs photoniques reconfigurables et auto-adaptatives.The central aim of this thesis is the exploration of potential applications of molecular spin crossover complexes in electronic and photonic devices. To this aim vacuum thermal deposited, high quality, crystalline thin films of the complex [Fe(HB(tz)3)2] (tz = (1,2,4-triazol-1-yl), displaying robust, above-room-temperature spin crossover, were incorporated into two- and three-terminal device configurations. Large-area, vertical junctions were formed by ITO/[Fe(HB(tz)3)2]/Al stacks. The junctions exhibited up to three orders of magnitude resistance drop when switching from the low-spin to the high-spin state. They revealed also high resistance to fatigue both on storage (> 1 year) and on repeated switching (>10,000) in ambient air. The resistance switching mechanism could be linked to the intrinsic charge transport in the spin crossover film. Similar multilayer junctions with magnetic electrodes were also fabricated for the first time. [Fe(HB(tz)3)2] films were then incorporated into organic field-effect transistors. Different device configurations were created (bottom gate/bottom contact, bottom gate/top contact) - aiming for the use of the spin crossover phenomenon to modulate the transfer/output characteristics of the transistors. Despite considerable difficulties in achieving reproducible temperature-dependent characterizations, we could evidence changes of the device characteristics, which may be related to the spin crossover phenomenon. In parallel, multilayer Ag/[Fe(HB(tz)3)2]/Ag Fabry-Perot cavities were also fabricated. These devices use the remarkable refractive index switching (Δn = 0.04 - 0.2) between the low-spin and high-spin states in the [Fe(HB(tz)3)2] film to achieve modulation of the cavity resonance. This wavelength tuneability is coupled with low absorption losses in the visible and near infrared spectral ranges, providing scope for reconfigurable and self-adaptive photonics applications

Dispositifs électroniques et optiques à base de complexe à transition de spin [Fe(HB(1,2,4-triazol-1-yl)3)2]

The central aim of this thesis is the exploration of potential applications of molecular spin crossover complexes in electronic and photonic devices. To this aim vacuum thermal deposited, high quality, crystalline thin films of the complex [Fe(HB(tz)3)2] (tz = (1,2,4-triazol-1-yl), displaying robust, above-room-temperature spin crossover, were incorporated into two- and three-terminal device configurations. Large-area, vertical junctions were formed by ITO/[Fe(HB(tz)3)2]/Al stacks. The junctions exhibited up to three orders of magnitude resistance drop when switching from the low-spin to the high-spin state. They revealed also high resistance to fatigue both on storage (> 1 year) and on repeated switching (>10,000) in ambient air. The resistance switching mechanism could be linked to the intrinsic charge transport in the spin crossover film. Similar multilayer junctions with magnetic electrodes were also fabricated for the first time. [Fe(HB(tz)3)2] films were then incorporated into organic field-effect transistors. Different device configurations were created (bottom gate/bottom contact, bottom gate/top contact) - aiming for the use of the spin crossover phenomenon to modulate the transfer/output characteristics of the transistors. Despite considerable difficulties in achieving reproducible temperature-dependent characterizations, we could evidence changes of the device characteristics, which may be related to the spin crossover phenomenon. In parallel, multilayer Ag/[Fe(HB(tz)3)2]/Ag Fabry-Perot cavities were also fabricated. These devices use the remarkable refractive index switching (Δn = 0.04 - 0.2) between the low-spin and high-spin states in the [Fe(HB(tz)3)2] film to achieve modulation of the cavity resonance. This wavelength tuneability is coupled with low absorption losses in the visible and near infrared spectral ranges, providing scope for reconfigurable and self-adaptive photonics applications.L'objectif central de cette thèse est l'exploration des applications potentielles des complexes moléculaires à transition de spin dans les dispositifs électroniques et photoniques. Dans ce but, des films minces cristallins de haute qualité, déposés thermiquement sous vide, du complexe [Fe(HB(tz)3)2] (tz = (1,2,4-triazol-1-yl), présentant une bistabilité robuste à température ambiante, ont été incorporés dans des dispositifs à deux et trois bornes. Des jonctions verticales de grande surface ont été formées par des empilements ITO/[Fe(HB(tz)3)2]/Al. Ces jonctions ont présenté une chute de résistance allant jusqu'à trois ordres de grandeur lors du passage de l'état bas spin à l'état haut spin. Elles ont également révélé une grande résistance à la fatigue lors du stockage (> 1 an) et lors de commutations répétées (>10 000) à l'air ambiant. Le mécanisme de commutation de résistance pourrait être lié au transport de charge intrinsèque au film de complexe à transition de spin. Des jonctions multicouches similaires avec des électrodes magnétiques ont également été fabriquées pour la première fois. Des films de [Fe(HB(tz)3)2] ont été par la suite incorporés dans des transistors organiques à effet de champ. Différentes configurations ont été réalisées (grille inférieure/contact inférieur, grille inférieure/contact supérieur) - dans le but d'utiliser le phénomène de transition de spin pour moduler les propriétés des transistors. Malgré des difficultés considérables pour obtenir des caractérisations reproductibles en fonction de la température, nous avons pu mettre en évidence de modifications de différentes caractéristiques en fonction de la température, qui pourraient être liées à la transition de spin. En parallèle, des cavités multicouches Ag/[Fe(HB(tz)3)2]/Ag de type Fabry-Perot ont également été fabriquées. Ces dispositifs utilisent la commutation remarquable de l'indice de réfraction (n = 0,04 - 0,2) entre les états bas spin et haut spin dans le film [Fe(HB(tz)3)2] pour réaliser la modulation de la résonance de la cavité. Cette possibilité d'ajustement de la longueur d'onde centrale est associée à de faibles pertes d'absorption dans les domaines spectraux du visible et du proche infrarouge, ce qui ouvre la voie au développement des dispositifs photoniques reconfigurables et auto-adaptatives