Entwicklung eines Infektions- und Screening-Modell für Clostridium difficile im Zebrafisch

Clostridium difficile (C. difficile) infection (CDI) is an antibiotic-associated intestinal disease and is considered to be the main cause of healthcare-associated infections. The typical symptom of CDI manifests as mild to moderate diarrhea and pseudomembranous colitis. The hallmarks of the disease include neutrophil infiltration, and lesions in the colonic epithelium. C. difficile produces two major virulence factors, named TcdA and TcdB. Both toxins translocate the N-terminal glucosyltransferase domain (GTD) into the cytosol of target cells and inactivate Rho GTPases by glucosylation. This inactivation causes cell rounding, a redistribution of the actin cytoskeleton, and further an apoptotic cytotoxic effect. Although metronidazole and vancomycin remain the main drugs to treat CDI in the last three decades, new treatments or non-antibiotics agents are needed due to the emergence of hypervirulent strains. In the first part of this study, a stable transgenic zebrafish that expresses the GTD of TcdA/B under the control of a hatching gland specific enhancer was established. This model would be used for screening and identifying pharmacological substances against Tcd toxicity. Meanwhile, this zebrafish model was co-expressed a fluorescence-based apoptosis biosensor with the GTD of TcdA/B. Thus, the physiological condition of hatching gland cells was monitored by fluorescent signal. The innate immune system plays a crucial role in CDI onset and progression. In the second part of this study, the response of macrophages and neutrophils against C. difficile was analyzed. Using the Gal4/UAS system, a stable transgenic zebrafish line with expression of yellow Citrine fluorescent protein in neutrophils was generated. To combine this line for monitoring macrophages simultaneously, the binary transcriptional LexA/lexAop system was applied to express the fluorescent red tagRFP-T protein in macrophages. Both macrophages and neutrophils were able to phagocytose C. difficile. Furthermore, to unravel the function of macrophages in C. difficile elimination, Tamoxifen-inducible Caspase was co-expressed in the macrophage transgenic strain to trigger apoptosis (ATTACTM). The ablation and regeneration kinetics of macrophages were characterized by counting the number of RFP-positive cells. This model represents a tool to analyze the progression of CDI in the presence or absence of macrophages.Die Clostridium difficile (C. difficile) Infektion (CDI) ist eine Antibiotika-assoziierte Darmerkrankung und gilt als Hauptverursacher von therapieassoziierten Infektionen. Das Symptom der CDI lässt sich als leichter bis mittelschweren Durchfall und pseudomembranöse Kolitis charakterisieren. Die Merkmale der Krankheit umfassen die Infiltration von Neutrophilen und Läsionen im Colonepithel. C. difficile produziert zwei Hauptvirulenzfaktoren (TcdA/B). Beide Toxine verlagern die N-terminale Glycosyltransferasedomäne (GTD) in das Zytosol von Zielzellen und inaktivieren dabei Rho-GTPasen durch Glycosylierung. Die Inaktivierung verursacht Zellabrunden, sowie Umverteilen des Aktinzytoskeletts und Apoptose. Obwohl Metronidazol und Vancomycin als Hauptmittel zur Behandlung von CDI in den letzten drei Jahrzehnten genutzt wurden, ist es notwendig aufgrund des Auftretens von hypervirulenten Stämmen neue Behandlungsmethoden oder nicht Antibiotika gebundene Medikamente zu entwerfen. Im ersten Teil dieser Forschung wurde ein stabiler transgener Zebrafisch etabliert, der die GTD-Domäne unter Kontrolle eines hatching gland-spezifischen Enhancers exprimiert. Das Modell wurde zum Screening und zur Identifizierung von pharmakologischen Substanzen gegen Tcd-Toxizität verwendet. Ein Fluoreszenz-basierter Apoptose-Biosensor wird mit der GTD coexprimiert. Somit kann der physiologische Zustand der Schlupfdrüsenzellen überwacht werden. Das angeborene Immunsystem spielt eine entscheidende Rolle bei der Entstehung und Progression von CDI. Im zweiten Teil dieser Forschung wurde die Reaktion von Makrophagen und Neutrophilen auf eine C. difficile Infektion analysiert. Unter Verwendung des Gal4/UAS-Systems wurde eine transgene Zebrafischlinie mit Expression von gelb floureszierenden Citrin in Neutrophilen erzeugt. Um diese mit der simultanen Überwachung von Makrophagen zu kombinieren, wurde das LexA/LexAop-System zur Expression des rot floureszierende RFP-Proteins in diesen genutzt. Makrophagen und Neutrophile konnten C. difficile über Phagozytose aufnehmen. Um die Funktion von Makrophagen bei der C. difficile-Infektion zu analysieren, wurde die Zelltod-auslösende Tamoxifen-induzierbare Caspase (ATTACTM) im Makrophagenstamm coexprimiert. Die Ablations- und Regenerationskinetik von Makrophagen konnte durch Zählen der RFP-positiven Zellen charakterisiert werden. Diese Larven stellen ein Werkzeug dar, um das Fortschreiten von CDI in Gegenwart oder Abwesenheit von Makrophagen zu analysieren

Variations du français et manuels de français langue étrangère en Chine

Le plurilinguisme et la diversité des langues constituent des ressources importantes de la société humaine. Diverses variations diaphasiques, diatopiques, diastratiques ainsi que socio-situationnelles coexistent au sein d’une même langue. La « compétence linguistique » permet de nuancer et d’utiliser ces variantes selon les contextes d’usage divers. Cependant, le registre « normé » neutre, univoque et basé sur l’écrit domine avec une priorité absolue dans la didactique et la rédaction des manuels de langues étrangères en Chine. Ainsi, nos apprenants arrivent seulement à oraliser le langage standard écrit, sans pouvoir varier ses niveaux de langage en fonction des contextes de communication (les conversations familières en particulier). Le présent travail tend à étudier le rôle de représentation des variations linguistiques dans les manuels de FLE et à sensibiliser nos apprenants, à travers une introduction multimodale, dès le début de l’apprentissage, à des usages variés du français moderne

Non-aligned supervision for Real Image Dehazing

Removing haze from real-world images is challenging due to unpredictable weather conditions, resulting in misaligned hazy and clear image pairs. In this paper, we propose a non-aligned supervision framework that consists of three networks - dehazing, airlight, and transmission. In particular, we explore a non-alignment setting by utilizing a clear reference image that is not aligned with the hazy input image to supervise the dehazing network through a multi-scale reference loss that compares the features of the two images. Our setting makes it easier to collect hazy/clear image pairs in real-world environments, even under conditions of misalignment and shift views. To demonstrate this, we have created a new hazy dataset called "Phone-Hazy", which was captured using mobile phones in both rural and urban areas. Additionally, we present a mean and variance self-attention network to model the infinite airlight using dark channel prior as position guidance, and employ a channel attention network to estimate the three-channel transmission. Experimental results show that our framework outperforms current state-of-the-art methods in the real-world image dehazing. Phone-Hazy and code will be available at https://github.com/hello2377/NSDNet

MonoNeRD: NeRF-like Representations for Monocular 3D Object Detection

In the field of monocular 3D detection, it is common practice to utilize scene geometric clues to enhance the detector's performance. However, many existing works adopt these clues explicitly such as estimating a depth map and back-projecting it into 3D space. This explicit methodology induces sparsity in 3D representations due to the increased dimensionality from 2D to 3D, and leads to substantial information loss, especially for distant and occluded objects. To alleviate this issue, we propose MonoNeRD, a novel detection framework that can infer dense 3D geometry and occupancy. Specifically, we model scenes with Signed Distance Functions (SDF), facilitating the production of dense 3D representations. We treat these representations as Neural Radiance Fields (NeRF) and then employ volume rendering to recover RGB images and depth maps. To the best of our knowledge, this work is the first to introduce volume rendering for M3D, and demonstrates the potential of implicit reconstruction for image-based 3D perception. Extensive experiments conducted on the KITTI-3D benchmark and Waymo Open Dataset demonstrate the effectiveness of MonoNeRD. Codes are available at https://github.com/cskkxjk/MonoNeRD.Comment: Accepted by ICCV 202

A Wasserstein distributionally robust planning model for renewable sources and energy storage systems under multiple uncertainties

Nowadays, electricity markets and carbon trading mechanisms can promote investment in renewable sources but also generate new uncertainties in decision-making. In this paper, a two-stage Wasserstein distributionally robust optimization (WDRO) model is presented to determine the optimal planning strategy for renewable energy generators (REGs) and energy storage systems (ESSs) in the distribution network. This model considers supply-side and demand-side uncertainties in the distribution network and the interaction uncertainty from the main grid which are depicted by the ambiguity sets based on the Wasserstein metric and historical data. Meanwhile, both 1-norm and -norm Wasserstein metric constraints are considered to satisfy the decision-makers different preference. Furthermore, to solve this WDRO model, a systematic solution method with a three-step process is developed. Numerical results from a modified IEEE 33-node system and a 130-node system in the real world demonstrate the advantages of the two-stage WDRO model and the effectiveness of the solution method.</p

Acquisition des voyelles nasales du français et interférences du cantonais

Les voyelles nasalisées par coarticulation sont communément trouvées dans de nombreuses langues ; cependant, les voyelles nasales en tant que phonèmes indépendants n’existent que dans peu de langues. Avec 3 voyelles nasales et une position spécifique de la langue et des lèvres, les voyelles nasales du français constituent une difficulté importante pour les apprenants cantonophones. Cet article vise à examiner les caractéristiques de l’interlangue des voyelles nasales françaises produites par des apprenants cantonophones. En comparant les taux de nasalité, la longueur des voyelles, les pics spectraux (formants) et la position des lèvres entre les apprenants cantonophones et les locuteurs natifs du français, nous avons remarqué des influences de la coarticulation nasale en L1 (le cantonais) sur l’interlangue des voyelles nasales françaises. Les résultats de l’analyse sont les suivants : 1) il existe une différence significative au niveau du taux de nasalité entre les apprenants et les locuteurs natifs enquêtés ; 2) la L1 joue un rôle important sur la longueur des voyelles et les valeurs maximales de la nasalité de la production des voyelles nasales ; 3) les apprenants éprouvent des difficultés dans l’arrondissement au cours de la production de certaines voyelles nasales françaises.The coarticulatory nasalized vowels can be commonly found in many languages in the world. Meanwhile, regarded as independent phoneme, the nasal vowels are present only in few languages. Featured by an important rate of nasalance and the specific position of the tongue and the lips, the French nasal vowels bring about some difficulties for Chinese students. This article aims at examining the characteristics of the interlanguage of French nasal vowels produced by Cantonese learners studying French in China. Experimental phonetics methodologies are used in this research in order to compare the nasalance, the duration of vowels, the formants and the position of the lips between the Cantonophone learners and the native French speakers. The influence of the nasal coarticulation in the learner’s L1 on the interlanguage of the nasal vowels in French is observed. The results of analysis show that: 1) there exists a significant difference in terms of nasalance in nasal vowels between the learners and the native French speakers; 2) L1 plays an important role in the duration of vowels and the maximum values of nasalance of French nasal vowels; 3) the learners experience difficulties in the roundedness of certain vowels

Superelasticity in bcc Nanowires by a Reversible Twinning Mechanism

Superelasticity (SE) in bulk materials is known to originate from the structure-changing martensitic transition which provides a volumetric thermodynamic driving force for shape recovery. On the other hand, structure-invariant deformation processes, such as twinning and dislocation slip, which result in plastic deformation, cannot provide the driving force for shape recovery. We use molecular-dynamics simulations to show that some bcc metal nanowires exhibit SE by a “reversible” twinning mechanism, in contrast to the above conventional point of view. We show that this reversible twinning is driven by the surface energy change between the twinned and detwinned state. In view of similar recent findings in fcc nanowires, we suggest that SE is a general phenomenon in cubic nanowires and that the driving force for the shape recovery arises from minimizing the surface energy. Furthermore, we find that SE in bcc nanowires is unique in several respects: first, the ‹111› / {112} stacking fault generated by partial dislocation is always preferred over ‹111› / {110} and ‹111› /{123} full dislocation slip. The occurrence of ‹111› / {112} twin or full dislocation slip in bcc nanowires depends on the competition between the emission of subsequent partial dislocations in adjacent {112} planes and the emission of partial dislocations in the same plane. Second, compared to their fcc counterparts, bcc nanowires have a higher energy barrier for the nucleation of twins, but a lower energy barrier for twin migration. This results in certain unique characteristics of SE in bcc nanowires, such as low energy dissipation and low strain hardening. Third, certain refractory bcc nanowires, such as W and Mo, can show SE at very high temperatures, which are higher than almost all of the reported high-temperature shape memory alloys. Our work provides a deeper understanding of superelasticity in nanowires and refractory bcc nanowires are potential candidates for applications in nanoelectromechanical systems operating over a wide temperature range

Amino acid permease RcAAP1 increases the uptake and phloem translocation of an L-valine-phenazine-1-carboxylic acid conjugate

Amino acid conjugates of pesticides can promote the phloem translocation of parent ingredients, allowing for the reduction of usage, and decreased environmental pollution. Plant transporters play important roles in the uptake and phloem translocation of such amino acid-pesticide conjugates such as L-Val-PCA (L-valine-phenazine-1-carboxylic acid conjugate). However, the effects of an amino acid permease, RcAAP1, on the uptake and phloem mobility of L-Val-PCA are still unclear. Here, the relative expression levels of RcAAP1 were found to be up-regulated 2.7-fold and 2.2-fold by the qRT-PCR after L-Val-PCA treatments of Ricinus cotyledons for 1 h and 3 h, respectively. Subsequently, expression of RcAAP1 in yeast cells increased the L-Val-PCA uptake (0.36 μmol/107 cells), which was 2.1-fold higher than the control (0.17 μmol/107 cells). Pfam analysis suggested RcAAP1 with its 11 transmembrane domains belongs to the amino acid transporter family. Phylogenetic analysis found RcAAP1 to be strongly similar to AAP3 in nine other species. Subcellular localization showed that fusion RcAAP1-eGFP proteins were observed in the plasma membrane of mesophyll cells and phloem cells. Furthermore, overexpression of RcAAP1 for 72 h significantly increased the phloem mobility of L-Val-PCA in Ricinus seedlings, and phloem sap concentration of the conjugate was 1.8-fold higher than the control. Our study suggested that RcAAP1 as carrier was involved in the uptake and phloem translocation of L-Val-PCA, which could lay foundation for the utilization of amino acids and further development of vectorized agrochemicals

The Effect of Reverse Strain on Microstructure and Strengthening of Copper Fabricated by Severe Plastic Deformation of Torsion Process

The unidirectional single torsion process of commercially pure copper was followed by different number of reverse turns of torsion deformation. The effect of reverse strain on the material refinement and hardening was investigated. It is found that the grain refinement is significantly blocked in the reverse torsion strain in comparison with that only suffered in monotonic torsion strain. The strengthening slightly decreases with the torsional direction change. This phenomenon is interpreted in terms of the average dislocation density. A qualitative assumption is proposed to explain the retarded phenomenon of material refinement and hardening in the reverse torsion process. The reverse strain maybe improves the uniformity and stress-strain equilibrium of severe plastic deformation induced material.DOI: http://dx.doi.org/10.5755/j01.ms.24.3.18414</p