Biofilm formation exacerbates bacterial infections and interferes with industrial processes. However, the dynamics of biofilm development, especially if formed by a combination of more than one species, is not entirely understood. Here, we present a microfluidic cultivation system that enables continuous imaging of biofilm growth using light sheet fluorescence microscopy (LSFM). We studied the development of biofilms of the human pathogens Staphylococcus aureus and Pseudomonas aeruginosa. Multidirectional LSFM imaging enables the calculation of a three-dimensional reconstruction of the biofilm structure with isotropic resolution. Whereas S. aureus forms 50-70-μm-thick mushroom-like structures, a P. aeruginosa biofilm is 10-15 μm thick with cell clusters 25 μm in diameter. A combined biofilm resulted in the formation of large mushroom-like clusters of S. aureus cells that were subsequently dispersed by invading P. aeruginosa. A higher inoculation ratio favoring P. aeruginosa resulted in the formation of small and stable S. aureus clusters overgrown with P. aeruginosa cells. Applying conditioned media from S. aureus and P. aeruginosa coculture to a single-species S. aureus biofilm induced its dispersion. Integrating a microfluidic system into LSFM enables the visualization of biofilm formation dynamics and the effects of compounds on biofilm development.

• Publication type
• Journal Article MeSH

We introduced mechanical strain to systematically roll monolayer (1-L) MoS2 into nanostructures with diameters ranging from 100 to 200 nm. The rolled MoS2 regions exhibit unique anisotropic optical behaviour compared to the flat regions (thickness ≤1 nm), as analysed through polarisation-resolved photoluminescence (PL) and Raman spectroscopy. Raman spectroscopy revealed that the E2g/A1g intensity ratio under circular polarisation was approximately 0.25 in the rolled regions, whereas it approached zero in the flat region. These findings highlight pronounced optical anisotropy and symmetry breaking in rolled MoS2, distinguishing it from the isotropic flat regions. Additionally, angular-dependent PL measurements demonstrated a strongly enhanced linear polarisation ratio (LPR) of 28% and a circular polarisation ratio (CPR) of 37% in the rolled regions, indicating strong optical anisotropy. In contrast, the flat MoS2 regions exhibited isotropic behaviour, with LPR and CPR values typically around 8%. Our results demonstrate that rolling-induced localised deformation profoundly modifies exciton polarisation behaviour in MoS2. Enabling precise light filtering and nanoscale manipulation via nanoscrolling of the two-dimensional materials, our work lays the foundation for next-generation optoelectronic devices with tailored optical responses and enhanced functionality.

• Publication type
• Journal Article MeSH

Transient absorption (TA) is the most widespread method to follow ultrafast dynamics in molecules and materials. The related method of TA anisotropy (TAA) reports on the ultrafast reorientation dynamics of transition dipole moments, reporting on phenomena ranging from electronic dephasing to orientational diffusion. While these are fundamental aspects complementary to TA, TAA is generally less widely used. The main reason is that TAA signals are usually not measured directly but are retrieved from two consecutive TA measurements with parallel (R‖) and perpendicular (R⊥) polarization of pump and probe pulses. This means that even minor systematic errors in these measurements lead to drastic changes in the TAA signal. In this work, the authors demonstrate alternating shot-to-shot detection of R‖ and R⊥, minimizing systematic errors due to laser fluctuations. The employed broadband detection lets us discuss effects dependent on detection wavelength in the ultrafast anisotropy decay of 2,3-naphthalocyanine, a system previously scrutinized by David Jonas and co-workers. In particular, we compare timescales of population relaxation and decoherence and support the proposals for isotropic type of relaxation in square symmetric molecules.

• Publication type
• Journal Article MeSH

Thylakoid membranes (TMs) of oxygenic photosynthetic organisms are flat membrane vesicles, which form highly organised, interconnected membrane networks. In vascular plants, they are differentiated into stacked and unstacked regions, the grana and stroma lamellae, respectively; they are densely packed with protein complexes performing the light reactions of photosynthesis and generating a proton motive force (pmf). The maintenance of pmf and its utilisation for ATP synthesis requires sealing the TMs at their highly curved regions (CRs). These regions are devoid of chlorophyll-containing proteins but contain the curvature-inducing CURVATURE THYLAKOID1 (CURT1) proteins and are enriched in lipids. Because of the highly curved nature of this region, at the margins of grana and stroma TMs, the molecular organisation of lipid molecules is likely to possess distinct features compared to those in the major TM domains. To clarify this question, we isolated CR fractions from Spinacia oleracea and, using BN-PAGE and western blot analysis, verified that they are enriched in CURT1 proteins and in lipids. The lipid phase behaviour of these fractions was fingerprinted with 31P-NMR spectroscopy, which revealed that the bulk lipid molecules assume a non-bilayer, isotropic lipid phase. This finding underpins the importance of the main, non-bilayer lipid species, monogalactosyldiacylglycerol, of TMs in their self-assembly and functional activity.

• Keywords
• 31P‐NMR, CURT1 protein, granum margin, non‐bilayer lipid phase, thylakoid membrane,
• MeSH
• Lipids * chemistry   MeSH
• Plant Proteins metabolism   MeSH
• Spinacia oleracea * metabolism   MeSH
• Thylakoids * metabolism   chemistry   MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Lipids * MeSH
• Plant Proteins MeSH

BACKGROUND: The hypothalamus (HT) plays a crucial role in regulating eating behaviors. Disruptions in its function have been linked to the development of weight-related disorders. Nevertheless, its characterization remains a challenge. OBJECTIVES: We assessed the structural alterations of individual HT nuclei related to eating behaviors in patients with weight-related disorders, and their association with body mass index (BMI) and severity of eating disorders. METHODS: Forty-four young females with normal weight (HC, n = 21), restrictive anorexia nervosa (AN, n = 13), and living with obesity (OB, n = 10) were explored in vivo using 7-T high-resolution (0.6 mm isotropic voxel) T1 quantitative magnetic resonance imaging (MRI). Volumes and quantitative T1 values of individual HT nuclei were compared after whole-brain normalization using nonparametric tests (corrected for multiple comparisons for groups and regions). We investigated the parameters associated with BMI and eating disorders, such as MRI parameters of HT nuclei, ghrelin and leptin levels, depression, and anxiety using multivariate nonlinear partial least square (NIPALS). RESULTS: Both AN and OB showed higher volumes of HT relative to HC (Zscores: 0.78 ± 1.06; 1.43 ± 1.51). AN showed significantly higher volumes and T1 values of the right paraventricular nucleus (PaVN) (volume Zscore: 1.82 ± 1.45; T1 Zscore: 3.76 ± 4.67), and higher T1 values of the left PaVN (Zscore: 2.25 ± 2.37) and right periventricular nuclei (Zscore: 3.73 ± 4.81). NIPALS models showed that lower BMI in AN was associated with structural alterations of the bilateral PaVN, right anterior commissure, and left fornix (FX). Higher BMI in OB was associated with structural alterations within the right PaVN, bilateral FX, left posterior hypothalamic nucleus, right lateral HT, and right anterior hypothalamic area. Finally, the severity of eating disorders was associated with larger structural alterations within the bilateral PaVN, bilateral arcuate hypothalamic nuclei, right bed nucleus of stria terminalis, left medial preoptic nucleus, and right tubero-mammillary hypothalamic nucleus. CONCLUSIONS: Weight-related disorders are associated with significant micro and macrostructural alterations in HT nuclei involved in eating behaviors.

• Keywords
• 7T, eating disorders, ghrelin, hypothalamic nuclei, hypothalamus, leptin, obesity, quantitative T(1) MRI, restrictive anorexia nervosa, volume,
• MeSH
• Adult MeSH
• Hypothalamus * diagnostic imaging   pathology   MeSH
• Body Mass Index MeSH
• Leptin blood   MeSH
• Humans MeSH
• Magnetic Resonance Imaging * MeSH
• Anorexia Nervosa * diagnostic imaging   pathology   MeSH
• Adolescent MeSH
• Young Adult MeSH
• Obesity * diagnostic imaging   pathology   MeSH
• Check Tag
• Adult MeSH
• Humans MeSH
• Adolescent MeSH
• Young Adult MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Leptin MeSH

The light reactions of oxygenic photosynthesis are performed by protein complexes embedded in the lipid bilayer of thylakoid membranes (TMs). Bilayers provide optimal conditions for the build-up of the proton motive force (pmf) and ATP synthesis. However, functional plant TMs, besides the bilayer, contain an inverted hexagonal (HII) phase and isotropic phases, a lipid polymorphism due to their major, non-bilayer lipid species, monogalactosyldiacylglycerol (MGDG). The lipid phase behavior of TMs is explained within the framework of the Dynamic Exchange Model (DEM), an extension of the fluid-mosaic model. DEM portrays the bilayer phase as inclusions between photosynthetic supercomplexes - characterized by compromised membrane impermeability and restricted sizes inflicted by the segregation propensity of lipid molecules, safe-guarding the high protein density of TMs. Isotropic phases mediate membrane fusions and are associated with the lumenal lipocalin-like enzyme, violaxanthin de-epoxidase. Stromal-side proteins surrounded by lipids give rise to the HII phase. These features instigate experimentally testable hypotheses: (i) non-bilayer phases mediate functional sub-compartmentalization of plant chloroplasts - a quasi-autonomous energization and ATP synthesis of each granum-stroma TM assembly; and (ii) the generation and utilization of pmf depend on hydrated protein networks and proton-conducting pathways along membrane surfaces - rather than on strict impermeability of the bilayer.

• MeSH
• Models, Biological MeSH
• Photosynthesis MeSH
• Galactolipids metabolism   MeSH
• Lipid Bilayers metabolism   MeSH
• Plants * metabolism   MeSH
• Thylakoids * metabolism   chemistry   MeSH
• Publication type
• Journal Article MeSH
• Review MeSH
• Names of Substances
• Galactolipids MeSH
• Lipid Bilayers MeSH

UNLABELLED:

Introduction: Songbirds, especially corvids, and parrots are remarkably intelligent. Their cognitive skills are on par with primates and their brains contain primate-like numbers of neurons concentrated in high densities in the telencephalon. Much less is known about cognition and neuron counts in more basal bird lineages. Here, we focus on brain cellular composition of galliform birds, which have small brains relative to body size and a proportionally small telencephalon and are often perceived as cognitively inferior to most other birds. METHODS: We use the isotropic fractionator to assess quantitatively the numbers and distributions of neurons and nonneuronal cells in 15 species of galliform birds and compare their cellular scaling rules with those of songbirds, parrots, marsupials, insectivores, rodents, and primates. RESULTS: On average, the brains of galliforms contain about half the number of neurons found in parrot and songbird brains of the same mass. Moreover, in contrast to these birds, galliforms resemble mammals in having small telencephalic and dominant cerebellar neuronal fractions. Consequently, galliforms have much smaller absolute numbers of neurons in their forebrains than equivalently sized songbirds and parrots, which may limit their cognitive abilities. However, galliforms have similar neuronal densities and neuron counts in the brain and forebrain as equally sized non-primate mammals. Therefore, it is not surprising that cognitive abilities of galliforms are on par with non-primate mammals in many domains. CONCLUSION: Comparisons performed in this study demonstrate that birds representing distantly related clades markedly differ in neuronal densities, neuron numbers, and the allocation of brain neurons to major brain divisions. In analogy with the concept of volumetric composition of the brain, known as the cerebrotype, we conclude that distantly related birds have distinct neuronal cerebrotypes.

• Keywords
• Brain size, Cognition, Evolution, Intelligence, Number of neurons,
• MeSH
• Biological Evolution MeSH
• Species Specificity MeSH
• Galliformes * anatomy & histology   physiology   MeSH
• Brain * cytology   anatomy & histology   MeSH
• Neurons * cytology   physiology   MeSH
• Parrots * anatomy & histology   physiology   MeSH
• Cell Count MeSH
• Telencephalon cytology   MeSH
• Songbirds * anatomy & histology   physiology   MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Comparative Study MeSH

Purpose To develop a deep learning tool for the automatic segmentation of the spinal cord and intramedullary lesions in spinal cord injury (SCI) on T2-weighted MRI scans. Materials and Methods This retrospective study included MRI data acquired between July 2002 and February 2023. The data consisted of T2-weighted MRI scans acquired using different scanner manufacturers with various image resolutions (isotropic and anisotropic) and orientations (axial and sagittal). Patients had different lesion etiologies (traumatic, ischemic, and hemorrhagic) and lesion locations across the cervical, thoracic, and lumbar spine. A deep learning model, SCIseg (which is open source and accessible through the Spinal Cord Toolbox, version 6.2 and above), was trained in a three-phase process involving active learning for the automatic segmentation of intramedullary SCI lesions and the spinal cord. The segmentations from the proposed model were visually and quantitatively compared with those from three other open-source methods (PropSeg, DeepSeg, and contrast-agnostic, all part of the Spinal Cord Toolbox). The Wilcoxon signed rank test was used to compare quantitative MRI biomarkers of SCI (lesion volume, lesion length, and maximal axial damage ratio) derived from the manual reference standard lesion masks and biomarkers obtained automatically with SCIseg segmentations. Results The study included 191 patients with SCI (mean age, 48.1 years ± 17.9 [SD]; 142 [74%] male patients). SCIseg achieved a mean Dice score of 0.92 ± 0.07 and 0.61 ± 0.27 for spinal cord and SCI lesion segmentation, respectively. There was no evidence of a difference between lesion length (P = .42) and maximal axial damage ratio (P = .16) computed from manually annotated lesions and the lesion segmentations obtained using SCIseg. Conclusion SCIseg accurately segmented intramedullary lesions on a diverse dataset of T2-weighted MRI scans and automatically extracted clinically relevant lesion characteristics. Keywords: Spinal Cord, Trauma, Segmentation, MR Imaging, Supervised Learning, Convolutional Neural Network (CNN) Published under a CC BY 4.0 license.

• Keywords
• Convolutional Neural Network (CNN), MR Imaging, Segmentation, Spinal Cord, Supervised Learning, Trauma,
• MeSH
• Deep Learning * MeSH
• Adult MeSH
• Image Interpretation, Computer-Assisted methods   MeSH
• Middle Aged MeSH
• Humans MeSH
• Magnetic Resonance Imaging * methods   MeSH
• Spinal Cord Injuries * diagnostic imaging   pathology   MeSH
• Retrospective Studies MeSH
• Aged MeSH
• Check Tag
• Adult MeSH
• Middle Aged MeSH
• Humans MeSH
• Male MeSH
• Aged MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Research Support, N.I.H., Extramural MeSH

Lattice structures, characterized by their repetitive, interlocking patterns, provide an efficient balance of strength, flexibility, and reduced weight, making them essential in fields such as aerospace and automotive engineering. These structures use minimal material while effectively distributing stress, providing high resilience, energy absorption, and impact resistance. Composed of unit cells, lattice structures are highly customizable, from simple 2D honeycomb designs to complex 3D TPMS forms, and they adapt well to additive manufacturing, which minimizes material waste and production costs. In compression tests, lattice structures maintain stiffness even when filled with powder, suggesting minimal effect from the filler material. This paper shows the principles of creating finite element simulations with 3D-printed specimens and with usage of the lattice structure. The comparing of simulation and real testing is also shown in this research. The efficiency in material and energy use underscores the ecological and economic benefits of lattice-based designs, positioning them as a sustainable choice across multiple industries. This research analyzes three selected structures-solid material, pure latices structure, and boxed lattice structure with internal powder. The experimental findings reveal that the simulation error is less than 8% compared to the real measurement. This error is caused by the simplified material model, which is considering the isotropic behavior of the used material PA12GB (not the anisotropic model). The used and analyzed production method was multi jet fusion.

• Keywords
• MJF, additive manufacturing, compression, lattice structures,
• Publication type
• Journal Article MeSH

We analyze magnetic properties of monolayers and bilayers of chromium iodide, [Formula: see text], in two different stacking configurations: AA and rhombohedral ones. Our main focus is on the corresponding Curie temperatures, hysteresis curves, equilibrium spin structures, and spin wave excitations. To obtain all these magnetic characteristic, we employ the atomistic spin dynamics and Monte Carlo simulation techniques. The model Hamiltonian includes isotropic exchange coupling, magnetic anisotropy, and Dzyaloshinskii-Moriya interaction. As the latter interaction is relatively weak in pristine [Formula: see text], we consider a more general case, when the Dzyaloshinskii-Moriya interaction is enhanced externally (e.g. due to gate voltage, mechanical strain, or proximity effects). An important issue of the analysis is the correlation between hysteresis curves and spin configurations in the system, as well as formation of the skyrmion textures.

• Publication type
• Journal Article MeSH