Onset Of Damage Research Articles

Influence of strain rate and temperature on the thermomechanical behavior of flax fibers/Elium acrylic composite: Experimental characterization and modeling

AbstractThis study investigated the viscoelastic behavior of unidirectional flax fibers/Elium acrylic composite reinforced with multiwall carbon nanotubes (MWCNT), focusing on their sensitivity to strain rate and temperature. In parallel, a cyclic tensile analysis was performed to monitor damage mechanisms in the composite. The results revealed enhanced mechanical and viscoelastic properties with increasing load and frequency. However, a reduction of 7°C in the relaxation associated to the glass transition temperature (Tg) was observed, as measured by dynamic mechanical analysis, in composites containing MWCNT. The study also highlighted the strain rate and temperature dependence of the flax fibers/Elium acrylic composite. Damage analysis revealed that the inclusion of MWCNTs delayed the onset of damage in the composite, suggesting that MWCNTs enhance material strength and improve durability. Additionally, a new model, combining Richeton's approach with numerical modeling, showed good agreement with experimental data.Highlights MWCNTs improved fiber‐matrix interface in flax/Elium composites. Strain rate sensitivity, even with MWCNTs. MWCNTs raised storage modulus and shifted Tg to lower temperatures. MWCNTs delayed damage, enhancing composite durability. The new model provides a good prediction of elastic modulus.

Characterization, analysis and prediction of damage onset in adhesively bonded joints using fracture mechanics and acoustic emission monitoring technique

This study presents a new method for predicting the fatigue life of aluminum adhesive-bonded joints. The approach involves experimental tests to establish fatigue failure criteria using acoustic emission monitoring to detect damage onset, along with a finite element (FE) model to analyse changes in energy release rate at the embedded crack tip. The proposed method comprises three key steps. In the initial stage, a 3D failure surface criterion is experimentally generated, connecting the maximum total energy release rate (GT) and the mixed mode ratio (GII/GT) to the number of cycles (N) required for initiating the crack propagation. In the second step, the total energy release rate (GT) and the corresponding mixed mode ratio (GII/GT) at the crack tip of a single lap joint under different external loads are numerically determined utilizing the virtual crack closure technique. Mathematical equations linking the applied load (P) to the associated values of GTmax and GII/GT are established. Ultimately, once the energy release rate and mixed mode ratio for a given load are determined, the number of cycles required for initiation of crack growth can be extracted from the experimentally derived failure surface in the initial step. The predictive model shows excellent correlation with experimental data, depending solely on the adhesive system rather than joint design.

Pulse duration dependent effects of ultrafast laser induced damage on a 1030 nm multi-layer dielectric mirror for high repetition rate, high average power laser systems

High repetition rate, high peak, and average power laser systems are crucial for next-generation particle accelerators, inertial confinement fusion, and secondary particle sources. These applications demand durable laser optics, particularly interference coatings on optics lasting millions of shots at high fluence. This study focuses on designing, testing, and simulating multi-layer dielectric (MLD) mirrors for pulse durations of 260 fs, 77 fs, and 25 fs at 1030 nm wavelength and 45-degree incidence angle with p-polarization. S-on-1 laser-induced damage thresholds (LIDT) for varying pulse numbers were determined, with single-shot LIDT values of 0.98 Jcm-2, 1.63 Jcm-2, and 2.3 Jcm-2 for 25 fs, 77 fs, and 260 fs respectively. A strong correlation between blister shape and local fluence was observed, implying that the layer expansion in a blister depends on local fluence. We have also examined mechanisms responsible for laser-induced stress generation and energy release rates in blister formation. Damage mechanisms are further explored by finite-difference time-domain (FDTD) simulations, incorporating Keldysh strong field ionization, whose predictions were in excellent agreement with the onset of damage determined experimentally. These findings offer insights for enhancing MLD coating technology, promising more efficient and resilient laser systems for diverse scientific and industrial applications.

Fbxo11 maintains mitochondrial function and prevents podocyte injury in adriamycin-induced nephropathy by mediating the ubiquitin degradation of Fosl2

Mitochondrial dysfunction is a pivotal factor in the onset of podocyte damage, which is a central component in the pathogenesis of nephrotic syndrome (NS). However, the precise mechanisms underlying the changes in podocyte mitochondria remain elusive. Our study aims to clarify the potential mechanisms involved in the role of F-box protein 11 (Fbxo11) in NS, specifically concentrating on its impact on mitochondrial function. A mouse model was established by tail vein injection of adriamycin (ADR, 10 mg/kg) and was infected with lentivirus overexpressing Fbxo11. Mouse podocytes (MPC-5) were infected with lenti-Fbxo11-OE, followed by treatment with 0.4 μg/mL of ADR. We identified the decreased expression of Fbxo11 in mouse kidney tissues and MPC-5 cells induced by ADR. Lenti-Fbxo11-OE intervention relieved ADR-induced glomerular lesion, podocyte injury, and mitochondrial dysfunction. In vitro, overexpression of Fbxo11 in mouse podocytes improved mitochondrial function and reduced podocyte damage, thereby inhibiting podocyte apoptosis. Mechanistically, Fbxo11 decreased the protein expression of Fosl2 through ubiquitin-dependent proteasomal degradation. Rescue experiments revealed that overexpression of Fosl2 abolished the protective effects of Fbxo11 overexpression on mitochondrial damage and podocyte injury. Importantly, the regulatory effects of the Fbxo11/Fosl2 axis were reversed when treated with the mitochondrial fission inhibitor mdivi-1. Taken together, our results demonstrated that Fbxo11-mediated ubiquitin degradation of Fosl2 is critical for maintaining mitochondrial function and preventing podocyte injury during NS.

Environmental nanoparticles and respiratory health in vertebrates: Analyzing emerging health risks

Environmental nanoparticles have become an area of considerable concern owing to their potential health hazards, particularly for vertebrates subjected to contaminated environments. This review explores the ramifications of these particles on respiratory health, concentrating on their origins, pathways of exposure, and the mechanisms through which they elicit detrimental effects. The primary origins of environmental nanoparticles encompass industrial operations, vehicular emissions, agricultural activities, and the degradation of plastic waste, resulting in the proliferation of nano-sized plastics and other particulates within urban locales. The review delineates inhalation exposure pathways, underscoring the deposition of nanoparticles within the respiratory tract and the challenges posed to respiratory protection. The health ramifications of nanoparticle exposure are scrutinized, accentuating lung inflammation, oxidative stress, and immune responses provoked by inhaled particulates. Furthermore, the review deliberates on the long-term health risks linked to chronic exposure, including the potential onset of chronic respiratory diseases and structural damage to lung tissue. Additionally, the article addresses the limitations of extant research, highlighting the dearth of data pertaining to chronic, low-level nanoparticle exposure in natural environments. It concludes by proposing future directions for research and policy recommendations, including advanced toxicological investigations and regulatory frameworks designed to mitigate nanoparticle pollution. By synthesizing contemporary understanding and identifying critical gaps, this review aspires to elevate awareness regarding the pressing necessity for targeted interventions to safeguard vertebrate respiratory health against the escalating threat posed by environmental nanoparticles.

Better safe than sorry: the unexpected drought tolerance of a wetland plant (Cyperus alternifolius L.).

A common assumption of plant hydraulic physiology is that high hydraulic efficiency must come at the cost of hydraulic safety, generating a trade-off that raises doubts about the possibility of selecting both productive and drought-tolerant herbaceous crops. Wetland plants typically display high productivity, which requires high hydraulic efficiency to sustain transpiration rates coupled to CO2 uptake. Previous studies have suggested high vulnerability to xylem embolism of different wetland plants, in line with expected trade-offs. However, some hygrophytes like Cyperus alternifolius L. can also experience prolonged periods of low water levels leading to substantial drought stress. We conducted an in-depth investigation of this species' hydraulic safety and efficiency by combining gas exchange measurements, hydraulic measurements of leaf hydraulic efficiency and safety, optical measurements of xylem vulnerability to embolism, and determination of cell turgor changes under drought. Our data confirm the high hydraulic efficiency of this wetland species, but at the same time, reveal its surprising drought tolerance in terms of turgor loss point and critical water potential values inducing xylem embolism and hydraulic failure, which were well below values inducing turgor loss and full stomatal closure. C. alternifolius emerges as a highly productive plant that is also well-equipped to tolerate drought via a combination of early stomatal closure and delayed onset of hydraulic damage. The species might represent a model plant to develop crops combining two of the most desirable traits in cultivated plants, i.e., high yield and significant drought tolerance.

Could MOTS-C Levels in Children with Type 1 Diabetes Mellitus Be an İndicator for Early Diabetic Kidney Disease?

The aim of our study was to compare serum MOTS-c levels in children with Type 1 diabetes mellitus (T1DM) to those of healthy children. We also aimed to examine whether serum MOTS-c levels could be used as an early indicator of DKD by correlating with changes in GFR and microalbuminuria. We recruited 82 patients who were being treated for insulin-dependent diabetes at the outpatient pediatric endocrinology clinic. At study MOTS-c, urinary albümin excretion, eGFR, HbA1c were evaluated and diabetes-related clinical features and anthropometric measurements were collected. Patients were divided into subgroups according to diabetes duration, precence of albuminuria, glomerular hyperfiltration, eGFR decline and metabolic control. The levels of MOTS-C were significantly lower in the Tip1DM group (76.2±1.3mg/dl) than in the control group (105.2±7.0, p=0.00). No significant difference in MOTS-c levels was found among the subgroups categorized by diabetes duration, obesity, metabolic control, hypertension and hyperlipidemia, glomerular hyperfiltration, decline in eGFR, and presence of microalbuminuria. The simple linear regression analysis results indicated that MOTS-C was not predictive for marker of diabetic kidney disease. In current study, MOTS-c was lower in the type 1DM group than in healthy children. However, the lack of association with microalbuminuria, hyperfiltration, and eGFR decline suggested that MOTS-c is not an early marker in diabetic kidney disease. This finding suggests that the onset of oxidative damage and mitochondrial dysfunction in T1DM is independent of diabetic kidney disease. Additionally, the study suggests that HBA1C and duration of diabetes are significant risk factors, while changes in eGFR and microalbuminuria continue to serve as indicators of diabetic kidney disease.

Effectiveness of application of epoxy compound without powder filler to re-pair ship propellers damaged under cavitation

Epoxy compositions are wide-spread in repairing the ship propellers blades damaged under cavitation attack. Most of the epoxy repair compositions contain the metal powders as filler. But the manufacturers of such compositions do not substantiate the expediency of using the metal powder in epoxy compositions for repairing the blades with cavitation wear spots. And the issue of the influence of metal powder filler on the cavitation wear resistance of the epoxy composition remains open. Experiments on ultrasonic magnetostrictive rig allowed drawing the conclusion, that the epoxy compositions containing the metal powder filler — Devcon Bronze Putty and Devcon Titanium Putty, and also compound K-153 doped with bronze powder — wear out without incubation period, that is the material loss takes place from the very beginning of the cavitation attack. The boundaries between the metallic particles and the epoxy matrix are the spots of the cavitation damage onset, and the composition wears out by the way of metal particles removal and subsequent destruction of the formed voids edges. Testing the compound K-153 without metal powder filler showed that refusal to add the metallic powder filler into epoxy repair compounds leads to the change in kinetics of cavitation wear of epoxy compound: there the incubation period appears on the kinetic curve of wear, during the period the quality of the surface of epoxy does not deteriorate as the removal of wear particles from the epoxy surface is absent. The application of the epoxy compositions without metal powder filler to repair the cavitation wear zones on ship propellers blades can result in essential fuel saving. It is explained by that quality of the repair composition surface does not decrease significantly; hence the propeller efficiency does not decrease. The savings might amount to 80 to 250 rubles per 1kW of ship diesel power during each interval between dock repairs.

Effect of laminae count and manufacturing methods on mechanical properties of thin‐ply woven composites

AbstractThin‐ply woven composites exhibit exceptional mechanical performance by delaying the onset of damage, making them suitable for high‐performance structural applications. This study outlines the impact of manufacturing techniques (vacuum bagging and hot pressing), ply count, and fiber waviness on the mechanical properties of aromatic thermosetting copolyester/carbon‐fiber (ATSP/CF) composites. The analysis encompasses several different ply counts, evaluating their effects on the in‐plane elastic modulus (0°–90°) and tensile strength. Results demonstrate that reducing the waviness (or crimp) ratio significantly enhances the in‐plane elastic modulus, with improvements up to 188%, highlighting the importance of fiber alignment. Vacuum bagging produced ply thicknesses from 128 to 58 μm for 1–36 plies, with in‐plane elastic moduli from 30.3 to 87.2 GPa, and 4‐ and 8‐ply samples showed approximately 40% higher stiffness than those made by hot pressing. ATSP resin with high thermal stability (up to 400°C) and recyclability was used. Furthermore, this study highlights the microstructural enhancements achieved through vacuum bagging, as revealed by scanning electron and optical microscopy, and micro‐computed tomography imaging. This paper provides insights into damage mitigation and achieving enhanced mechanical properties by controlling fiber waviness using vacuum bagging and higher ply count in thin‐ply ATSP/CF composites.Highlights Crimp ratio reduction enhances elastic in‐plane elastic modulus up to 188%. Vacuum bagging increases modulus over the hot pressing manufacturing method by 40%. Lowering thickness‐per‐ply increases failure strain from 0.8% to 1.2%. Explored the performance of a novel ATSP matrix with high recyclability and thermal stability.

Comparative study of thermal runaway characteristics between sodium-ion battery and Li-ion battery under heat abuse

Abstract This study investigates the thermal runaway characteristics of lithium-ion batteries and sodium-ion batteries under external heating conditions. By collecting temperature, strain, and voltage data, the thermal runaway behavior of two-type batteries is compared. Results show that lithium-ion batteries experience rapid temperature rise and early onset of internal damage, evidenced by sharp voltage drop and increased temperature rise rate. In contrast, sodium-ion batteries demonstrate slower TR onset but exhibit more severe thermal runaway effects, including higher peak temperatures and significant physical damage due to combustion. The comparative analysis indicates that lithium-ion batteries trigger TR earlier but with less severe damage, while sodium-ion batteries, despite their later onset, undergo more intense thermal runaway events. These findings highlight the importance of strengthening safety protocols and materials to address thermal runaway behavior under different battery thermal abuse.

Energy-based method for the failure criterion and resistance evaluation of marine clay under cyclic loading

Energy dissipation can macroscopically synthesize the evolutions in the microstructure of the marine clay during cyclic loading. Hence an energy-based method was employed to investigate the failure criterion and cyclic resistance of marine clay. A series of constant-volume cyclic direct simple shear tests was conducted on undisturbed saturated marine clay from the Yangtze Estuary considering the effects of the plasticity index (IP) and cyclic stress ratio (CSR). The results indicated that a threshold CSR (CSRth) exhibiting a power function relationship with IP exists in marine clay, which divides the cyclic response into non-failure and failure states. For failed specimens, the development of energy dissipation per cycle (Wi) with the number of cycles (N) exhibited an inflection point owing to the onset of serious damage to the soil structure. In this regard, the energy-based failure criterion was proposed by considering the inflection point as the failure point. Consequently, a model was proposed to quantify the relationships between failure energy dissipation per cycle (Wf) [or failure accumulative energy dissipation (Waf)], initial vertical effective stress, IP, and the number of cycles to failure (Nf,E). An evaluation model capturing the correlation among CSR, IP, and Nf,E was then established to predict the cyclic resistance, and its applicability was verified. Compared with the strain-based cyclic failure criterion, the energy-based failure criterion provides a more robust and rational approach. Finally, a failure double-amplitude shear strain (γDA,f) evaluation method applicable to marine clay in different seas was presented for use in practical geotechnical engineering.

Hypoxic irreversible brain cells damage, associated risk factors and antihypoxants

It is reported that in the final stage of many diseases the immediate cause of biological death in humans and warm-blooded animals is hypoxic irreversible damage to brain cells. This explains the fact that to prevent biological death in all critical conditions without exception, inhalation with breathing gases containing oxygen has long been successfully used. This is also why oxygenation of the blood is considered one of the main conditions for preserving human life in all critical situations and forms the basis of emergency medical care in the intensive care unit. However, inhalation of oxygen gas and increasing blood oxygen saturation should be carried out as early as possible, and more precisely — before the onset of the stage of hypoxic irreversible damage in brain cells. The fact is that after the onset of irreversible da­mage brain cells die even in the presence of oxygen. In this connection, the mechanisms of adaptation of the organism to oxygen deficiency play a great role for longer preservation of brain cells viability and human life in conditions of hypoxemia. In order to increase resistance to hypoxemia, antihypoxants are traditionally used. But they can preserve the viability of brain cells not always, but only if they are introduced into the body before the onset of hypoxic irreversible damage to brain cells and in the case of unused reserves of adaptation to hypoxemia in the body. Risk factors of hypoxic irreversible damage of brain cells are indicated, among which excessively long duration of hypoxemia and hyperthermia are emphasized. It is shown that the most important circumstance for the development of hypoxic irreversible damage of brain cells is not so much the degree of hypoxemia as the degree of hypoxia of brain tissue and its duration, which exceeds the period of human resistance to hypoxia. It has been shown that human resistance to hypoxia can be assessed using the Stange test. It has been reported that fever and local cerebral hyperthermia decrease, and hibernation and local cerebral hypothermia increase, the resistance of brain cells to hypoxia. In this regard, recommendations not only to eliminate fever and local inflammatory processes in the head, but also recommendations to reduce brain temperature are highly appropriate to improve resistance to hypoxia. It is pointed out that among the methods of local therapeutic hypothermia, targeted temperature management is the most advanced. In addition, it is reported that in recent years a new group of promising antihypoxants — alkaline solutions of hydrogen peroxide — has been created. It is shown that hydrogen peroxide is able to decompose very quickly into water and oxygen gas under the action of catalase, which is found in all tissues. The peculiarities of using alkaline solutions of hydrogen peroxide as antihypoxants we all have to study in the future.

Capturing drought stress signals: the potential of dendrometers for monitoring tree water status.

The severity of droughts is expected to increase with climate change, leading to more frequent tree mortality and a decline in forest ecosystem services. Consequently, there is an urgent need for monitoring networks to provide early warnings of drought impacts on forests. Dendrometers capturing stem diameter variations may offer a simple and relatively low-cost opportunity. However, the links between stem shrinkage, a direct expression of tree water deficit (TWD), and hydraulic stress are not well understood thus far. In this study, we exposed two widespread conifers Pinus sylvestris L. and Larix decidua Mill. to lethal dehydration by withholding water and closely monitored TWD, midday water potential ($\psi $) and midday stomatal conductance (${\textit g}_{\textit s}$) under controlled greenhouse conditions. We found strong relationships between the three variables throughout the dehydration process, particularly suggesting the potential for continuous $\psi $ predictions and stomatal closure assessments. However, the relationships decoupled during recovery from severe drought. We also identified TWD thresholds that signal the onset of drought stress and tissue damage, providing insights into stress impacts and recovery potential. While these findings are promising, challenges remain in practically transferring them to field set-ups by suitable TWD normalization. Importantly, we observed that midday ${\textit g}_{\textit s}$ was drastically reduced when TWD persisted overnight, providing a directly applicable drought stress signal that does not require normalization. In conclusion, while challenges remain, our results highlight the potential of dendrometers for monitoring tree water dynamics. Implementing dendrometer networks could support the development of early warning metrics for drought impacts, enabling large-scale monitoring in diverse settings, such as urban areas and forest ecosystems.

Simulating the onset of damage in DCDC tests using a novel gradient‐extended damage model for tension‐compression asymmetry

AbstractIn the present work, an existing framework for gradient‐extended damage is extended to simulate the damage onset in double cleavage drilled compression (DCDC) tests. The main idea is to consider the different evolution of the damage variable under tensile and compressive loading. More specifically, the star‐convex decomposition is exploited to split the strain energy into an active part and an inactive part, and only the active part drives the evolution of the damage variable in the compressive regime. A parameter adopted in the star‐convex decomposition is applied to calibrate the compressive strength independently from the tensile strength, such that the current model can simulate different types of the damage onset. Furthermore, the strengthening effect induced by damage hardening is discussed in this work.

An innovative approach to study the influence of microstructure on thermal shock resistance of porous ceramics

AbstractPorosity is a critical microstructural factor in ceramic materials, influencing their mechanical and thermal properties. However, the detailed mechanisms through which porosity, grain size, and grain boundary fracture energy affect the thermal shock resistance of porous ceramics are still not fully understood. This study introduces a dual‐scale model that integrates these microstructural parameters to predict fracture toughness and thermal shock resistance. Using the single‐edge V‐notch fracture toughness testing principle, we calculate the thermal stress intensity factor and establish its relationship with temperature differentials. The critical temperature differential, which marks the onset of thermal shock damage, is determined when the thermal stress intensity factor reaches the fracture toughness threshold. The model reveals a significant interplay between porosity, grain size, and grain boundary fracture energy, with fine‐grained ceramics (grain size < 10 µm) showing a sharp decrease in fracture toughness as porosity increases, while coarser‐grained ceramics are less affected by porosity. These findings provide a deeper understanding of the microstructural optimization needed to enhance the thermal shock resistance of high‐performance porous ceramics.

Contact damage response of alumina-based layered architectures under different loading configurations

Hertzian contact damage upon spherical indentation is investigated in alumina-based ceramics designed with embedded textured compressive layers. The effect of the location of the embedded layer and the testing configuration (parallel or normal to the layer orientation) on the sub-surface damage evolution is explored. An acoustic emission system for crack detection and post-mortem cross sectioning are employed to evaluate the onset and extension of damage in the different samples. Distinct acoustic signals detected at different contact loads are correlated with the onset of the ring crack, cone crack propagation and quasi-plastic deformation within the textured layer. The distinct damage mechanisms are influenced by the location of the embedded textured compressive layer and the loading orientation with respect to the layers. The design of layered ceramics for contact applications should consider the loading orientation as well as the contact stress field with respect to the “protective” layer to enhance damage tolerance.

One-year risk of all-cause death and major cardiovascular events in patients presenting with hypertensive crisis. A report from a global federated research health network

Abstract Background Few data are available about the clinical course of patients presenting with hypertensive crisis who are discharged alive from hospital. Purpose To assess the long-term risk of adverse events in patients with hypertensive crises. Methods Retrospective study utilizing a research health network. Based on the ICD-10-CM codes recorded between 2000 and 2022, from 85 health care associations mainly located in the United States, patients with hypertensive crisis were subdivided into hypertensive urgencies (I16.0) and hypertensive emergencies (I16.1). In those with hypertensive emergencies, the type of target organ damage was reported, ie. central nervous system (ischemic stroke, hypertensive encephalopathy, intracerebral hemorrhages), cardiovascular (CVS: myocardial infarction (MI), heart failure (HF), aorta dissection (AD)), or renal (acute kidney failure). Primary outcomes were the one-year risks of all-cause death, and major cardiovascular events (MACE: MI, stroke, cardiac arrest, AD, and HF). Secondary outcomes were the risks for each type of MACE. Cox regression analysis after propensity score matching (PSM) 1:1 was used to produce hazard ratios (HRs) and 95% Confidence Intervals (95%CIs). Results Overall, we identified 25 294 patients with hypertensive emergency (age 62.4±15.7, 46.1% females) and 21,737 patients with hypertensive urgency (age 63.5±17.2, 55.5% females). Patients with hypertensive emergency were more likely males, Black or African American origin and showed a higher prevalence of chronic hypertensive-related complications, vs. those with hypertensive urgency. After PSM, patients with hypertensive emergency showed a higher risk of all-cause death (HR, 1.34, 95%CI 1.25-1.44) and MACE (HR 4.09, 95%CI 3.87-4.33), vs. those with hypertensive urgency. Of the secondary outcomes, patients with hypertensive emergency had increased risks of MI (HR 3.33, 95%CI 3.03-3.67), stroke (HR 4.73, 95%CI 4.33-5.17), cardiac arrest (HR 1.30, 95%CI 1.07-1.58), AD (HR 5.49, 95%CI 3.90-7.73), and HF (HR 3.01, 95%CI 2.74-3.14). All the different types of organ involvement during the hypertensive emergency were each associated with similar long-term risks of adverse events (Figure 1). Conclusion Patients with hypertensive emergency have a high long-term risk of MACE and all-cause death. Preventing the onset of target organ damage in patients with hypertensive crisis is crucial to mitigate their long-term risk of adverse events.

Resistance of Boron Nitride Nanotubes to Radiation-Induced Oxidation.

We present unprecedented results on the damage thresholds and pathways for boron nitride nanotubes (BNNT) under the influence of energetic electrons in an oxidative gas environment, using an environmental aberration-corrected electron microscope over a range of oxygen pressures. We observe a damage cascade process that resists damage until a higher electron dose, compared with carbon nanotubes, initiating at defect-free BNNT sidewalls and proceeding through the conversion from crystalline nanotubes to amorphous boron nitride (BN), resisting oxidation throughout. We compare with prior results on the oxidation of carbon nanotubes and present a model that attributes the onset of damage in both cases to a physisorbed oxygen layer that reduces the threshold for damage onset. Surprisingly, increased temperatures offer protection against damage, as do electron dose rates that significantly exceed the oxygen dose rates, and our model attributes both effects to a physisorbed oxygen population.

Therapeutic Options for Crigler–Najjar Syndrome: A Scoping Review

Crigler–Najjar Syndrome (CNS) is a rare genetic disorder caused by mutations in the UGT1A1 gene, leading to impaired bilirubin conjugation and severe unconjugated hyperbilirubinemia. CNS presents in the following forms: CNS type 1 (CNS1), the more severe form with the complete absence of UGT1A1 activity, and CNS type 2 (CNS2), with partial enzyme activity. This narrative review aims to provide a detailed overview of CNS, highlighting its clinical significance and the need for new, more effective treatments. By summarizing current knowledge and discussing future treatments, this article seeks to encourage further research and advancements that can improve outcomes for CNS patients. The literature analysis showed that CNS1 requires aggressive management, including phototherapy and plasmapheresis, but liver transplantation (LT) remains the only definitive cure. The timing of LT is critical, as it must be performed before the onset of irreversible brain damage (kernicterus), making early intervention essential. However, LT poses risks such as graft rejection and lifelong immunosuppression. CNS2 is milder, with patients responding well to phenobarbital and having a lower risk of kernicterus. Recent advancements in gene therapy and autologous hepatocyte transplantation offer promising alternatives to LT. Gene therapy using adeno-associated virus (AAV) vectors has shown potential in preclinical studies, though challenges remain in pediatric applications due to liver growth and pre-existing immunity. Autologous hepatocyte transplantation avoids the risk of rejection but requires further research. These emerging therapies provide hope for more effective and less invasive treatment options, aiming to improve the quality of life for CNS patients and reduce reliance on lifelong interventions.

Role of Nitric oxide synthase II in cognitive impairment due to experimental cerebral malaria

The role of nitric oxide (NO) in the pathogenesis of cerebral malaria and its cognitive sequelae remains controversial. Cerebral malaria is still the worst complication of Plasmodium falciparum infection, which is characterized by high rates of morbidity and mortality. Even after recovery from infection due to antimalarial therapy, the development of cognitive impairment in survivors reinforces the need to seek new therapies that demonstrate efficacy in preventing long-lasting sequelae. During disease pathogenesis, reactive oxygen and nitrogen species (RONS) are produced after the established intense inflammatory response. Increased expression of the enzyme inducible nitric oxide synthase (iNOS) seems to contribute to tissue injury and the onset of neurological damage. Elevated levels of NO developed by iNOS can induce the production of highly harmful nitrogen-reactive intermediates such as peroxynitrite. To address this, we performed biochemical and behavioral studies in C57BL6 mice, aminoguanidine (specific pharmacological inhibitor of the enzyme iNOS) treated and iNOS−/−, infected with Plasmodium berghei ANKA (PbA), with the aim of clarifying the impact of iNOS on the pathogenesis of cerebral malaria. Our findings underscore the effectiveness of both strategies in reducing cerebral malaria and providing protection against the cognitive impairment associated with the disease. Here, the absence or blockade of the iNOS enzyme was effective in reducing the signs of cerebral malaria detected after six days of infection. This was accompanied by a decrease in the production of pro-inflammatory cytokines and reactive oxygen and nitrogen species. In addition, nitrotyrosine (NT-3), a marker of nitrosative stress, was also reduced. Futher, cognitive dysfunction was analyzed fifteen days after infection in animals rescued from infection by chloroquine treatment (25 mg/kg bw). We observed that both interventions on the iNOS enzyme were able to improve memory and learning loss in mice. In summary, our data suggest that the iNOS enzyme has the potential to serve as a therapeutic target to prevent cognitive sequelae of cerebral malaria.