Structural Integrity Research Articles

Bio-inspired Chemistry for Developing Micro/Nano Structured Nanofiber Membranes for Membrane Distillation

Membrane distillation (MD) holds significant promise for effluent purification to mitigate the global water shortage. However, the existing petroleum-based MD membranes suffer from high costs, limited sustainability, and wetting issues. Herein, we employed biosynthetic bacterial cellulose (BC) as the substrate and successfully achieved a uniform and stable dispersion of ZnO nanoflowers onto the BC nanofibers through in-situ synthesis technology. After undergoing a fluorination process, a superhydrophobic membrane was prepared by the synergistic effect of micro/nano structures and low surface energy. The resulting membrane exhibited exceptional properties, including a remarkable contact angle of 151.7°, a substantial liquid entry pressure of 2.5 bar, and exhibiting structural integrity and high hydrophobicity even under harsh conditions. Furthermore, this strategy ensured exceptional membrane porosity (∼94.9%), increased the permeation flux and reduced conductive heat transfer, thereby enhancing the thermal efficiency of the membrane. Furthermore, the membrane demonstrated effective bactericidal activity and self-cleaning capability, facilitating easy cleaning and extending service life. These properties endow the membrane with an impressive durability. After 96 h of continuous operation, the membrane maintained a stable permeation flux of 10.29 L⋅m−2⋅h−1 and an extraordinary salt rejection rate exceeding 99.9%. Notably, even with the addition of sodium dodecyl sulfate to the feed, the membrane exhibited stable permeation flux and outstanding antiwetting properties. In summary, the MD membrane fabricated using the bio-inspired chemistry demonstrated a promising potential for long-term applications in direct contact MD operations.

Eco-friendly encapsulation: Investigating plant-based protein-alginate shells for efficient delivery and digestion of hemp seed oil encapsulated via supercritical CO2 dispersion

In this study, supercritical carbon dioxide solution-enhanced dispersion (SEDS) was used to encapsulate hemp seed oil (HSO) within matrices of hemp seed protein isolate (HPI), pea protein (PPI) and soy protein (SPI) (0.5 % w/v) in complex with alginate (AL) (0.01 % w/v). The effects of different pH levels (3–9), NaCl concentrations (0–200 mmol/L) and simulated gastrointestinal conditions on HSO release and digestion patterns were analyzed. The findings revealed that SPI/AL microcapsules effectively maintained structural integrity and controlled oil release across diverse pH levels and salt concentrations. During gastrointestinal phases, minimal oil release was observed during oral digestion (<25 % for all samples), while significant (P < 0.05) gastric release occurred in PPI/AL (55.4 %) and SPI/AL (78.1 %) microcapsules. Surprisingly, HPI/AL microcapsules exhibited delayed and sustained release (27.9 %), indicating their potential as ideal wall material for delivering sensitive food and pharmaceutical ingredients to the intestinal stage while minimizing damage in the harsh gastric environment.

A putative cAMP-binding protein in Trypanosoma brucei cooperates with FLAM3 to promote flagellar connection and cell morphogenesis

Trypanosoma brucei is a flagellated parasitic protozoan, and within the insect vector the parasite transitions from the trypomastigote form to the epimastigote form by re-positioning its mitochondrial genome and re-locating the flagellum. The mechanisms underlying such morphology changes are still poorly understood, but several flagellum-localized proteins are involved in this process by modulating the flagellum attachment zone (FAZ) that adheres the flagellum to the cell membrane. We report here a putative cAMP-binding protein named cAMP-BP1, which promotes flagellar connection and morphology transition. cAMP-BP1 contains two cyclic nucleotide-binding domains and five calcium-binding C2 domains and localizes to the flagella connector and the new FAZ tip. Depletion of cAMP-BP1 in the trypomastigote form of T. brucei causes major morphology changes, generating epimastigote-like cells with re-positioned kinetoplast and re-located flagellum. At the flagella connector and the new FAZ tip, cAMP-BP1 associates with FLAM3, a regulator of morphology transition, depends on the latter for localization, and is required for FLAM3 localization to the flagella connector. Knockdown of cAMP-BP1 inhibits FAZ elongation and disrupts flagellar connection by impairing flagella connector structural integrity. These results identify a flagella connector- and new FAZ tip-localized protein as a regulator of morphology transition and flagellar connection in trypanosomes and uncover its functional interplay with FLAM3 to promote FAZ elongation for maintaining trypomastigote morphology.

Thermal and magnetic evolution of an Earth-like planet with a basal magma ocean

Earth's geodynamo has operated for over 3.5 billion years. The magnetic field is currently powered by thermocompositional convection in the outer core, which involves the release of light elements and latent heat as the inner core solidifies. However, since the inner core nucleated no more than 1.5 billion years ago, the early dynamo could not rely on these buoyancy sources. Given recent estimates of the thermal conductivity of the outer core, an alternative mechanism may be required to sustain the geodynamo prior to nucleation of the inner core. One possibility is a silicate dynamo operating in a long-lived basal magma ocean. Here, we investigate the structural, thermal, buoyancy, and magnetic evolution of an Earth-like terrestrial planet. Using modern equations of state and melting curves, we include a time-dependent parameterization of the compositional evolution of an iron-rich basal magma ocean. We combine an internal structure integration of the planet with energy budgets in a coupled core, basal magma ocean, and mantle system. We determine the thermocompositional convective stability of the core and the basal magma ocean, and assess their respective dynamo activity using entropy budgets and magnetic Reynolds numbers. Our conservative nominal model predicts a transient basal magma ocean dynamo followed by a core dynamo after 1 billion years. The model is sensitive to several parameters, including the initial temperature of the core-mantle boundary, the parameterization of mantle convection, the composition of the basal magma ocean, the radiogenic content of the planet, as well as convective velocity and magnetic scaling laws. We use the nominal model to constrain the range of basal magma ocean electrical conductivity and core thermal conductivity that sustain a dynamo. This highlights the importance of constraining the parameters and transport properties that influence planetary evolution using experiments and simulations conducted at pressure, temperature, and composition conditions found in planetary interior, in order to reduce model degeneracies.

Si-P-Cu internally bonded anode: An innovative strategy for low-cost and high-performance pseudocapacitive Li-ion storage

Maintaining the structural integrity of silicon and phosphorus anodes during the Li+ insertion and extraction cycles poses a significant challenge. Inspired by the natural process of plant roots anchoring into soil, we present a simple yet effective method for integrating a SiP anode into the copper current collector. This approach involves subjecting readily available and cost-effective micrometre-sized silicon particles (50–150 μm) and red phosphorus to mechanochemical treatment. Subsequently, the resulting Si/P composite is coated onto copper foil and subjected to annealing treatment, resulting in the formation of an integrated structure, incorporating Cu3Si, Cu3P, and P-doped Si, firmly established within the copper current collector. The electrode obtained (BM-Si@P/Cu-350), promoted by a crosslinked (polyimide) PI binder, outperforms not only the ball-milled Si and red P but also the same electrode in which the annealing process is absent (BM-Si@P/Cu-100). During the mechanochemical treatment, red P acts as both the doping agent and a lubricant, facilitating the grinding of the Si particles into P-doped Si particles in the range of predominantly 200–300 nm; while during the thermal treatment, Si plays a key role in preventing excessive interaction between the P and the Cu current collector. Instead, a tailored rooting of the active material into the current collector is achieved through the formation of Cu3P and Cu3Si phases, not only increasing the mechanical stability of the electrode to endure volume changes during cycling and limit developing cracks, but also enhancing the electrical conductivity of the system. This article suggests a simple and potentially low-cost strategy for the utilization of highly available micrometre-sized silicon and red-P for Li-ion storage applications.

Exploring the nanobiohybrids of nanodiamonds-functionalized MoAlB@MBene and microalgae synergistic potential for sustainable pharmaceutical removal

Nanobiohybrid systems combine nanomaterials and biological, creating synergistic platforms for diverse applications. We successfully developed MoAlB@MBene using HCl/H2O2 mixture, transforming the densely packed nanolaminar MoAlB MAB phase into an expanded multilayered MBene’ structure, featuring open slit-shaped pores. EDS and XRF analysis suggested that the voids between the Mo-B layers were due to the removal of approximately one aluminum layer. The etching of the MAB phase also caused a transition in the zeta potential from 1.11 to −3.35. Such characteristics suggest a potential for MBene’ surface functionalization. SEM and EDS confirmed that functionalization with 1.0 wt% fluorescent nanodiamonds (FND) was optimal, and guaranteed uniform distribution of the FND. Such enrichment also ensured favorable optical properties, including fluorescence in the orange/red region and a reduced direct band gap value by incorporating FND (from 1.32 eV to 0.54 eV). Functionalization with FND also mitigated the ecotoxicological properties of MoAlB@MBene. We observed sustained proliferation even at a concentration of 500 mg L−1 of the nanocomposite, with toxicity plateauing after 48 h of incubation. Optimization of encapsulation with sodium alginate suggested the best concentration (1.5 wt%) and cross-linking time (10 min), allowing for structural integrity, sphericality, and rapid microalgae growth. The fluorescent nanocomposite within encapsulated microalgae improved the decomposition rate of tetracycline (18 vs 45 %) and doxycycline (14 vs 48 %), achieving almost threefold enhancement within 24 h. Furthermore, it positively influenced microalgae growth, counteracting pharmaceuticals toxic effects. Altogether, these findings provide insights into developing and maintaining nanobiohybrid systems, incorporating fluorescent nanocomposite and microalgae, combining the knowledge from environmental protection and materials science.

The effect of enzymatic GAG degradation on transverse shear properties of porcine cornea

The structural integrity of cornea depends on properties of its extracellular matrix, mainly a mixture of collagen fibers and soluble proteoglycans (PGs). PGs are macromolecules of negatively charged sulphated glycosaminoglycans (GAGs) covalently attached to a protein core. GAGs appear as bridges between adjacent collagen fibers and could facilitate force transfer between them. Furthermore, GAGs are responsible for corneal hydration by attracting and maintaining water molecules into the extracellular matrix. Based on these observations, GAGs are expected to be essential for biomechanical properties of cornea. The primary objective of the present study was to determine the effects of GAGs on shear properties of cornea. For this purpose, GAGs were enzymatically removed from porcine corneal disks by keratanase II enzyme. After confirming the successful removal of GAGs by histochemical methods, torsional rheometry was performed to characterize the shear stiffness of GAG-depleted samples as a function of axial strain. It was found that the shear modulus of all samples was a function of applied shear strain and compressive strain. Beyond the range of linear viscoelastic response, the average complex shear modulus decreased with increasing the shear strain. Increasing the axial strain from 0% to 40% significantly increased the average complex shear modulus of corneal disks in all groups. Finally, the enzyme treatment with keratanase II enzyme significantly decreased the shear stiffness. The experimental measurements were discussed in terms of microstructural and compositional properties of corneal extracellular matrix and it was concluded that GAGs play a significant role in defining the shear properties of cornea.

Papermaking-inspired sustainable triboelectric sensors for intelligent detecting system

Digitalization not only drives the intelligent transformation of industries while fostering cultural diversity and innovation. Cutting-edge triboelectric sensing technology inspired by traditional Chinese papermaking fabricates a bamboo paper-based triboelectric nanogenerator (BP-TENG). The addition of high-purity bacterial cellulose improves the structural integrity of the resulting paper. The proposed BP-TENG exhibits excellent electrical performance, generating an output voltage of 88 V and a maximum output power of 0.9 mW at a low-frequency motion of 2 Hz. Moreover, the BP-TENG is combined with machine learning algorithms to build a multi-scene intelligent detecting system, including real-time handwriting-to-speech conversion, personalized jump prediction and smart home automation systems. The machine learning algorithm can achieve a recognition accuracy of up to 99.8 %. This multi-scene intelligent detecting system boasts superior accuracy, environmental sustainability and affordability, ideal for communication security, sports health monitoring and smart building applications.

Bearing witness: Medical education and reflecting on the Holocaust then and now

Background Despite advocacy from the Association of American Medical Colleges (AAMC) and The Lancet Commission on medicine, Nazism, and the Holocaust, Holocaust education is lacking in medical education. To address this gap, students at Geisinger Commonwealth School of Medicine (GCSOM) viewed an Association of American Medical College (AAMC) webinar about medicine during the Holocaust as part of the required curriculum for first year medical students introduced in 2022. Methods As part of their doctoring course, Physician and Patient Centered Care (PPCC), students viewed the AAMC webinar “The legacy of the role of medicine during the Holocaust and its contemporary relevance” and participated in two structured reflections: a written reflection on how webinar topics inform students' professional development and a verbal reflection on learning from the Holocaust to develop a sense of moral courage, advocacy, and activism in medicine. Researchers conducted qualitative analysis of written reflections and analyzed session surveys to determine key themes and impact of the session. Results Of the 108 enrolled in PPCC, 59 (54.6%) completed a post session Likert scale survey assessing the impact of the webinar on their personal and professional development. As an average, respondents moderately agreed that the webinar impacted their personal and professional development, with 91% slightly, moderately, or strongly agreeing. Additionally, thematic analysis of required written reflections indicated a majority of students (62.5%) identified the need for additional medical humanities education about the Holocaust and its relevance to medicine. Conclusion Holocaust education encourages medical students to bear witness to past medical atrocities and critically assess the profession and their personal–professional growth. Continued structured integration of the Holocaust in medical education supports critical self-reflection and the development of morally courageous physicians who endorse and practice social accountability in medicine.

Evaluation of glass fiber-reinforced polymer bars for application in sections of reinforced concrete

In order to evaluate the effectiveness and acceptability of glass fiber reinforced polymer (GFRP) bars as a substitute for conventional steel reinforcement, this study looks into their use in reinforced concrete sections. To assess the mechanical qualities of GFRP bars, the research includes mix design, casting, and extensive testing, such as flexural and tensile tests. Furthermore, a comprehensive study of GFRP-integrated reinforced concrete building sections is carried out, looking at factors like primary stresses, bending stresses, shear stresses, and deflection. Additionally, using ANSYS software, a comparative study of beam-column junctions using GFRP and RCC sections is conducted to evaluate structural performance under various loading circumstances. The results demonstrate how GFRP bars can improve building projects' structural integrity, toughness, and sustainability

Corrosion Rate Optimization and Prediction for Enhanced Strength and Structural Integrity of Pipeline Weldments Using RSM and ANN

This study investigates the optimization and prediction of non-elastic performance factors required to augment the pipeline weldments' structural integrity and strength. The study's main focus is on the components of the operation, like the welding current, voltage, and gas flow rate to optimize and predict the corrosion rate of the pipeline weldment. Utilizing Design Expert software for experimental design and data analysis, the study employs the Central Composite Design (CCD) methodology to generate a quadratic model that predicts the responses effectively. The research also integrates Artificial Neural Networks (ANN) to further enhance the prediction accuracy. Experimental results indicate that the optimal welding parameters 160 amps current, 21.28 volts voltage, and 14.67 liters/min gas flow rate—yield a corrosion rate of 0.018 mm/yr. The study concludes that both RSM and ANN can be effectively used for optimization and prediction in welding processes, with RSM showing slightly better predictive capabilities.

Development of a P(L-D,L)LA Foam as a Dura Substitute and Its In Vitro Evaluation

Dura substitutes are used to reduce the risk of postoperative complications following neurosurgical interventions, and to facilitate the healing of dura damages or defects caused by injuries. Traditional tissue transplants have limitations like limited tissue availability, potential risk of immune rejection and disease transmission. The use of biomaterials composed of synthetic polymers as dura substitutes offers a promising approach to overcome these limitations to replace and treat damaged dura mater. Potential biocompatible porous scaffolds still need to be developed to minimize the risks of immune response and disease transmission, while also ensuring effective cell migration and cell ingrowth in three dimension. The aim of the present study was to develop a poly(L-lactide-co-D,L-lactide) (P(L-D,L)LA) foam with an optimal pore size for dura mater substitution, investigate its morphological characteristics, and evaluate its potential for dura mater regeneration by assessing the spreading and growth of meningeal cells within it through in vitro studies. Foams were produced by lyophilization using different concentrations of P(L-D,L)LA solution. A GMP-grade P(L-D,L)LA, suitable for medical device applications, was used in this study. Morphological analysis was performed using scanning electron microscopy, and porosity of the foams was studied with mercury porosimetry. In in vitro studies, meningeal cells were seeded onto the polymeric foams, and their behavior and proliferation in these scaffolds were investigated with cytoskeleton and nucleus staining, and colorimetric cell proliferation assay, respectively. Scanning electron microscopy results showed that the foams prepared with 2.5% and 3% polymer solutions displayed good structural integrity and convenient interconnectivity, with pore sizes ranging from 80 to 150 µm. However, the foams prepared with 2% and 4% polymer solution demonstrated poor structural integrity and low interconnectivity, respectively. In vitro studies showed that the foams prepared with 2.5% and 3% polymer solutions served effectively as scaffolds for meningeal cells, and the cells attached, spread and homogeneously distributed. In addition, the cells proliferated and increased in number over time within these polymeric scaffolds. These findings suggest that the foams produced with 2.5% and especially 3% P(L-D,L)LA polymer solutions could effectively serve as a suitable substitute for the dura mater, providing an appropriate environment for cell ingrowth and tissue integration. This indicates that the developed foam could be a promising treatment for dura mater damage or defects, with the potential approach to promote regeneration in future in vivo and clinical studies.

ER–mitochondria contact sites regulate hepatic lipogenesis via Ip3r-Grp75-Vdac complex recruiting Seipin

BackgroundMitochondria and endoplasmic reticulum (ER) contact sites (MERCS) constitute a functional communication platform for ER and mitochondria, and they play a crucial role in the lipid homeostasis of the liver. However, it remains unclear about the exact effects of MERCs on the neutral lipid synthesis of the liver.MethodsIn this study, the role and mechanism of MERCS in palmitic acid (PA)-induced neutral lipid imbalance in the liver was explored by constructing a lipid metabolism animal model based on yellow catfish. Given that the structural integrity of MERCS cannot be disrupted by the si-mitochondrial calcium uniporter (si-mcu), the MERCS-mediated Ca2+ signaling in isolated hepatocytes was intercepted by transfecting them with si-mcu in some in vitro experiments.ResultsThe key findings were: (1) Hepatocellular MERCs sub-proteome analysis confirmed that, via activating Ip3r-Grp75-voltage-dependent anion channel (Vdac) complexes, excessive dietary PA intake enhanced hepatic MERCs. (2) Dietary PA intake caused hepatic neutral lipid deposition by MERCs recruiting Seipin, which promoted lipid droplet biogenesis. (3) Our findings provide the first proof that MERCs recruited Seipin and controlled hepatic lipid homeostasis, depending on Ip3r-Grp75-Vdac-controlled Ca2+ signaling, apart from MERCs’s structural integrity. Noteworthy, our results also confirmed these mechanisms are conservative from fish to mammals.ConclusionsThe findings of this study provide a new insight into the regulatory role of MERCS-recruited SEIPIN in hepatic lipid synthesis via Ip3r-Grp75-Vdac complex-mediated Ca2+ signaling, highlighting the critical contribution of MERCS in hepatic lipid homeostasis.

Biohydrogen production from saline wastewater: An overview

The escalating global demand for sustainable energy has propelled the exploration of biohydrogen production with a promising avenue for simultaneously generating clean energy and managing waste effectively. This review mainly focuses on advances in sustainable biohydrogen production from saline wastewater, especially in a process that leverages the unique abilities of halotolerant and halophilic microorganisms adapted to high-salinity conditions. It provides an extensive understanding of various biohydrogen production methods, which are biophotolysis, photofermentation, dark fermentation, and microbial electrolysis. Additionally, this review elaborated on the enzymology of hydrogen production and the impact of salt stress, with a particular emphasis on the adaptive mechanisms of “salt-in” and “compatible solute” strategies. These adaptations are crucial for maintaining enzymatic activity and structural integrity under hypertonic conditions. Through a comprehensive examination of microbial pathways and strategies, this review aimed to furnish foundational insights that will drive future research and technological innovations in biohydrogen production.

Ambient Stability of Sodium-Doped Copper Oxide Obtained through Thermal Oxidation

The ambient stability of copper oxide layers produced through thermal oxidation is a critical factor for their application in advanced photovoltaic devices. This study investigates the long-term stability of thermally grown sodium-doped copper oxides fabricated at 300 °C, 500 °C, and 700 °C. The structural, optical, and electronic properties of these oxide layers were examined after a 30-day period to understand how thermal oxidation temperature and sodium doping influence the durability and properties of copper oxide films. The results indicate that the stability of thermal copper oxide increases with oxidation temperature. The film produced at 700 °C maintained consistent optical properties, work function value, and structural integrity over time, demonstrating their robustness against environmental degradation. In contrast, the layers produced at lower temperatures (300 °C and 500 °C) showed more significant changes due to continued oxidation and adsorption from ambient.

Mobile-integrated SRR-based four-port MIMO antenna for broadband mm-wave 5G applications

ABSTRACT A low-profile, single-layered, compact-size, highly-isolated four-port MIMO antenna integrated within a 5 G smartphone has been proposed for a futuristic mm-wave broadband communication system. The proposed MIMO antenna configuration has been derived from a conventional inset-fed rectangular microstrip patch by introducing two parallel I-shaped slots on the patch surface for operating over a wide bandwidth of 4.91 GHz, that is, from 26.78 to 31.69 GHz. The antenna geometry has an overall dimension of 20.9 mm x 20.9 mm x 0.787 mm. The proposed configuration attained a maximum gain of 8.11 dBi and radiation efficiency of 90% at 28 GHz resonating frequency. The integration of the square-shaped SRR structure among closely packed antenna elements has significantly enhanced the overall isolation by 13 dB without compromising the antenna’s physical dimensions. The realisation of the S-parameters has also been carried out from the equivalent circuit model to agree with the results obtained from the electromagnetic simulation through CST software. The measured radiation patterns assured the minimal variation with simulated characteristics along the E and H planes. A comprehensive safety investigation of the proposed MIMO antenna has been carried out to assess power densities (<10 W/ m 2 ) across different usage modes, including data, reading, and talking in a mobile application perspective. Several diversity parameters, including ECC (<0.0001), DG (>9.999 dB), CCL (<0.12 bits/sec/Hz), MEG, and TARC, have also been evaluated as performance metrics. Furthermore, the linear transmission property of the proposed MIMO antenna has been validated through the variation of group delay (<0.5 ns) over operating frequency bands in the far-field region.

Graphene nanoplatelet additive impact on compression and bending strength of S-2 glass face-sheet honeycomb sandwich panels: An experimental study

In this study, the three-point bending, edge-wise, and flat-wise strengths of Nomex® sandwich structures with un-doped S-2 glass fiber face-sheet (Neat/S-2/glass) and those with Graphene nanoplatelet-doped S-2 glass fiber face-sheet (GNPs/S-2/glass) were examined parametrically. In the macroscopic images obtained post-experimentation, the damage to the structures’ face layer, core, and interface with GNP (graphene nanoplatelet) additives was visualized. Morphological images depicting the damaged structures were obtained by applying image processing techniques to the macroscopic images. Finally, the fracture mechanisms of fiber/fiber and fiber/matrix interfaces within the shell layers were examined in SEM images. As a result of the study, the addition of GNPs increased the strength of the interfaces between the fiber layers and the fiber core within the face layers of S-2 glass face-sheet Nomex® sandwich structures, leading to a 40% enhancement in bending strength, a 14% improvement in core compressive strength, and a 2.85% increase in edge-wise compressive strength. Moreover, the delamination damage between the face layer and the core, which undermines the structural integrity of the sandwich structure, was not observed in GNPs/S-2/glass sandwich structures. Thus, the damage propagation throughout the sandwich structure contributed to enhancing its load-carrying capacity. The collapse extent of the sandwich structures, determined through image processing, measured 8676 mm in Neat/S-2/glass sandwiches, whereas it amounted to 10,410 mm in GNPs/S-2/glass sandwiches. The inclusion of GNPs additive augmented the collapse strength of the sandwich structure by 19.9%. Utilizing GNPs as a filler in the matrix material has been recognized as a practical approach to enhancing the mechanical strength of sandwich structures.

Structural and functional brain markers of cognitive impairment in healthcare workers following mild SARS-CoV-2 infection during the original stream

Abstract SARS-CoV-2 infection often involves the nervous system, leading to cognitive dysfunctions, fatigue, and many other neurological signs that are becoming increasingly recognized. Despite mild forms of the disease accounting for most cases worldwide, research on the pathophysiology driving mild COVID-19 has received little attention. In this respect, recent evidence has pointed out that around 30–40% of non-critical, mild-to-moderate severity COVID-19 survivors may display cognitive disturbances several months post-illness. Hence, the impact of COVID-19 on brain structure and function, though potential neuropathological mechanisms underpinning cognitive alterations in post-mild COVID-19 infections, remains largely unexplored. This retrospective multicenter observational cohort study, entirely based on a healthcare workers sample (n = 65; 55% females, aged 21-61), investigated the cognitive status and the structural and functional brain integrity among non-hospitalized individuals who developed mild COVID-19 symptoms during the occurrence of SARS-CoV-2 variants Alpha–to–Delta, compared with healthy controls tested before pandemic onset. All evaluations were performed at an average of 9-month follow-up post-infection period. Participants completed a comprehensive neuropsychological assessment and structural and functional MRI exams. Radiological inspection sought to detect the presence of white matter hyperintensities (WMHs) on axial fluid-attenuated inversion recovery (FLAIR) images. Global and regional gray matter (GM) integrity assessment, analyzing changes in GM volumes and cortical thinning, and functional connectivity alterations of resting-state brain networks were also conducted. Regression analyses tested the relationships between the presence of specific cognitive impairments and potential structural and functional brain findings. Our results revealed that clinical, cognitive screening and neuropsychological examinations were average between both groups, except for specific impairments related to executive functions in the mild COVID-19. Compared to healthy controls, mild COVID-19 subjects exhibited increased juxtacortical WMHs, thalamic and occipital volume loss, and diminished resting-state functional connectivity involving the left precuneus and cuneus in default-mode network and affecting right angular gyrus and left precuneus in the dorsal attentional network. Reduced thalamic volume was the only variable selected in the final model explaining the observed executive function impairment in mild COVID-19. The presence of cognitive, structural, and functional brain abnormalities over time suggests that the action of widespread neurovascular and inflammatory phenomena on the nervous system might also occur in mild forms following COVID-19 infection rather than permanent brain damage linked to the direct or indirect action of the virus. Our findings emphasize the need to pay attention to the long-term brain-related consequences of mild COVID-19 infections during the original stream.

Multi-Omics Analysis Unravels the Impact of Stool Sample Logistics on Metabolites and Microbial Composition

Human health and the human microbiome are inevitably intertwined, increasing their relevance in clinical research. However, the collection, transportation and storage of faecal samples may introduce bias due to methodological differences, especially since postal shipping is a common practise in large-scale clinical cohort studies. Using four different Omics layer, we determined the structural (16S rRNA sequencing, cytometric microbiota profiling) and functional integrity (SCFAs, global metabolome) of the microbiota in relation to different easy-to-handle conditions. These conditions were storage at −20 °C, −20 °C as glycerol stock, 4 °C and room temperature with and without oxygen exposure for a maximum of one week. Storage time affected the microbiota on all Omics levels. However, the magnitude was donor-dependent, highlighting the need for purpose-optimized sample collection in clinical multi-donor studies. The effects of oxygen exposure were negligible for all analyses. At ambient temperature, SCFA and compositional profiles were stable for 24 h and 48 h, respectively, while at 4 °C, SCFA profiles were maintained for 48 h. The global metabolome was highly susceptible, already changing at 24 h in non-frozen conditions. Thus, faecal microbiota was best preserved on all levels when transported as a native sample frozen within 24 h, leading to the least biased outcomes in the analysis. We conclude that the immediate freezing of native stool samples for transportation to the lab is best suited for planned multi-Omics analyses that include metabolomics to extend standard sequencing approaches.

Specific iron binding to natural sphingomyelin membrane induced by non-specific co-solutes

HypothesisSphingomyelin (SPM), a crucial phospholipid in the myelin sheath, plays a vital role in insulating nerve fibers. We hypothesize that iron ions selectively bind to the phosphatidylcholine (PC) template within the SPM membrane under near-physiological conditions, resulting in disruptions to membrane organization. These interactions could potentially contribute to the degradation of the myelin sheath, thereby playing a role in the development of neurodegenerative diseases. ExperimentsWe utilized synchrotron-based X-ray spectroscopy and diffraction techniques to study the interaction of iron ions with a bovine spinal-cord SPM monolayer (ML) at the liquid-vapor interface under physiological conditions. The SPM ML serves as a model system, representing localized patches of lipids within a more complex membrane structure. The experiments assessed iron binding to the SPM membrane both in the presence of salts and with additional evaluation of the effects of various ion species on membrane behavior. Grazing incidence X-ray diffraction was employed to analyze the impact of iron binding on the structural integrity of the SPM membrane. FindingsOur results demonstrate that iron ions in dilute solution selectively bind to the PC template of the SPM membrane exclusively at near-physiological salt concentrations (e.g., NaCl, KCl, KI, or CaCl2) and are pH-dependent. In-significant binding was detected in the absence of these salts or at near-neutral pH with salts. The surface adsorption of iron ions is correlated with salt concentration, reaching saturation at physiological levels. In contrast, multivalent ions such as La3+ and Ca2+ do not bind to SPM under similar conditions. Notably, iron binding to the SPM membrane disrupts its in-plane organization, suggesting that these interactions may compromise membrane integrity and contribute to myelin sheath damage associated with neurological disorders.