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Double perovskite oxides, characterized by their tunable magnetic properties and robust interconnection between the lattice and magnetic degrees of freedom, present an enticing foundation for advanced magnetic refrigeration materials. Herein, we delve into the influence of rare-earth elements on RSrCoFeO6 (R = Sm, Eu) disordered double perovskites by examining their structural, electronic, magnetic, and magnetocaloric properties. Temperature-dependent synchrotron X-ray diffraction analysis confirmed the stability of the orthorhombic phase (Pnma) across a wide temperature range. X-ray photoemission spectroscopy revealed that both Sm and Eu are in the 3+ state, whereas multiple states for Co2+/3+ and Fe3+/4+ are identified. The magnetic investigation and magnetocaloric effect (MCE) analysis brought to light the presence of a long-range antiferromagnetic (AFM) order with a second-order phase transition (SOPT) in both samples. The maximum magnetic entropy change ΔSMmax was approximately 0.9 J/kg K for both samples at applied field 0-7 T, manifesting prominently above Neel temperatures TN ≈ 93 K (Sm) and 84 K (Eu). Nevertheless, different relative cooling powers (RCP) of 112.6 J/kg (Sm) and 95.5 J/kg (Eu) were observed. A detailed analysis of the temperature-dependent lattice parameters shed light on a distinct magnetocaloric effect across the magnetic transition temperature, unveiling an anisotropic thermal expansion [αV = 1.41 × 10-5 K-1 (Sm) and αV = 1.54 × 10-5 K-1 (Eu)] wherein the thermal expansion axial ratio αbSm/αbEu = 0.61 became lower with increasing temperature, which suggests that the Eu sample experiences a greater thermal expansion in the b-axis direction. At the atomic bonding level, the evidence for magnetoelastic coupling around the magnetic transition temperatures TN was found through the anomalies along the average Co/Fe-O bond distance, formal valence, octahedral distortion, as well as an anisotropic lattice expansion.
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Brain changes have been reported in the first weeks after SARS-CoV-2 infection. However, limited literature exists about brain alterations in post-COVID syndrome, a condition increasingly associated with cognitive impairment. The present study aimed to evaluate brain functional and structural alterations in patients with post-COVID syndrome, and assess whether these brain alterations were related to cognitive dysfunction. Eighty-six patients with post-COVID syndrome and 36 healthy controls were recruited and underwent neuroimaging acquisition and a comprehensive neuropsychological assessment. Cognitive and neuroimaging examinations were performed 11 months after the first symptoms of SARS-CoV-2. Whole-brain functional connectivity analysis was performed. Voxel-based morphometry was performed to evaluate grey matter volume, and diffusion tensor imaging was carried out to analyse white-matter alterations. Correlations between cognition and brain changes were conducted and Bonferroni corrected. Post-COVID syndrome patients presented with functional connectivity changes, characterized by hypoconnectivity between left and right parahippocampal areas, and between bilateral orbitofrontal and cerebellar areas compared to controls. These alterations were accompanied by reduced grey matter volume in cortical, limbic and cerebellar areas, and alterations in white matter axial and mean diffusivity. Grey matter volume loss showed significant associations with cognitive dysfunction. These cognitive and brain alterations were more pronounced in hospitalized patients compared to non-hospitalized patients. No associations with vaccination status were found. The present study shows persistent structural and functional brain abnormalities 11 months after the acute infection. These changes are associated with cognitive dysfunction and contribute to a better understanding of the pathophysiology of the post-COVID syndrome.
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COVID-19 , Substância Branca , Humanos , Imagem de Tensor de Difusão/métodos , Imageamento por Ressonância Magnética/métodos , SARS-CoV-2 , Encéfalo , Neuroimagem/métodos , Cognição/fisiologia , Substância Cinzenta , SíndromeRESUMO
BACKGROUND: Olfactory dysfunction is common during SARS-CoV-2 infection. The pathophysiology of the persistence of this symptom and the potential relationship with central nervous system involvement is unknown. AIM OF THE STUDY: To evaluate the neural correlates of persistent olfactory dysfunction in a series of patients with post-COVID syndrome. METHODS: Eighty-two patients with post-COVID syndrome were assessed with the Brief Smell Identification Test and a multimodal MRI study including 3D-T1, T2-FLAIR, diffusion-tensor imaging, and arterial spin labeling. Olfactory and neuroimaging examinations were performed 11.18 ± 3.78 months after the acute infection. Voxel-based brain mapping analyses were conducted to correlate the olfactory test with brain volumes, white matter microstructure, and brain perfusion. RESULTS: Olfactory dysfunction was associated with lower tissue perfusion in the orbital and medial frontal regions in the arterial spin labeling sequence. Conversely, no statistically significant findings were detected in brain volumes and diffusion-tensor imaging. Mild changes in paranasal sinuses and nasal cavities were detected in 9.75% of cases, with no association with olfactory deficits. CONCLUSIONS: We provide new insights regarding the pathophysiology of persistent olfactory dysfunction after COVID-19, involving the main brain regions associated with the olfactory system.
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COVID-19 , Transtornos do Olfato , COVID-19/complicações , Lobo Frontal/diagnóstico por imagem , Humanos , Transtornos do Olfato/diagnóstico por imagem , Transtornos do Olfato/etiologia , Perfusão , SARS-CoV-2 , OlfatoRESUMO
Size, shape and hot spots are crucial to optimize Raman amplification from metallic nanoparticle (NPs). The amplification from radius = 1.8 ± 0.4 nm ultra-small silver NPs was explored. Increasing NP density redshifts and widens their plasmon that, according to simulations for NPs arrays, is originated by the reduction of the interparticle distance, d, becoming remarkable for d ≤ R. Inter-particle interaction red-shifts (N130 nm) and widens (N90 nm) the standard plasmon of non-interacting spherical particles. Graphene partly delocalizes the carriers enhancing the NIR spectral weight. Raman amplification of graphene phonons is moderate and depends smoothly on d while that of Rhodamine 6G (R6G) varies almost exponentially due to their location at hotspots that depend strongly on d. The experimental correlation between amplification and plasmon position is well reproduced by simulations. The amplification originated by the ultra-small NPs is compared to that of larger particles, granular silver films with 7 < R < 15 nm grains, with similar extinction values. The amplification is found to be larger for the 1.8nm NPs due to the higher surface/volume ration that allows higher density of hot spots. It is demonstrated that Raman amplification can be efficiently increased by depositing low density layers of ultra-small NPs on top of granular films.
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BACKGROUND: The CUN-BAE (Clínica Universidad de Navarra-Body adiposity estimator) index is an anthropometric index based on age, sex and body mass index (BMI) for a refined prediction of body fatness in adults. CUN-BAE may help detect metabolically unhealthy individuals with otherwise normal weight according to BMI or waist circumference (WC). The aim of this study was to evaluate whether CUN-BAE, independent of its components (BMI, age and sex), was associated with cardiometabolic conditions including arterial hypertension, diabetes mellitus and metabolic syndrome (MetS). METHODS: The ENRICA study was based on a cross-sectional sample of non-institutionalized men and women representative of the adult Spanish population. Body weight, height, and WC were measured in all participants. The residual of CUN-BAE (rCUN-BAE), i.e. the part of the index not explained by its components, was calculated. The associations of CUN-BAE, rCUN-BAE, BMI and WC with hypertension, diabetes and MetS were analysed by multivariate logistic regression, and the Akaike information criterion (AIC) was calculated. RESULTS: The sample included 12,122 individuals. rCUN-BAE was associated with hypertension (OR 1.14, 95% CI 1.07-1.21) and MetS (OR 1.48, 1.37-1.60), but not with diabetes (OR 1.05, 0.94-1.16). In subjects with a BMI < 25 kg/m2, CUN-BAE was significantly associated with all three outcome variables. CUN-BAE was more strongly associated with the cardiometabolic conditions than BMI and WC and fit similar AICs. CONCLUSIONS: The CUN-BAE index for body fatness was positively associated with hypertension, diabetes and MetS in adults independent of BMI or WC. CUN-BAE may help to identify individuals with cardiometabolic conditions beyond BMI, but this needs to be confirmed in prospective settings.
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Tecido Adiposo , Índice de Massa Corporal , Diabetes Mellitus/diagnóstico , Hipertensão/diagnóstico , Síndrome Metabólica/diagnóstico , Adolescente , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Risco , Fatores Sexuais , Espanha , Adulto JovemRESUMO
Nanocolumnar titanium coatings have been fabricated in two sputtering systems with very different characteristics (a laboratory setup and semi-industrial equipment), thus possessing different morphologies (150â¯nm long columns tilted 20° from the normal and 300â¯nm long ones tilted 40°, respectively). These coatings exhibit similar antibacterial properties against Gram positive (Staphylococcus aureus) and Gram negative (Escherichia coli) bacteria. When a synergic route is followed and these coatings are functionalized with tellurium (Te) nanorods, the antibacterial properties are enhanced, especially for the long nanocolumns case. The biocompatibility is preserved in all the nanostructured coatings.
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Antibacterianos/farmacologia , Materiais Revestidos Biocompatíveis/farmacologia , Telúrio/farmacologia , Titânio/farmacologia , Antibacterianos/química , Materiais Revestidos Biocompatíveis/química , Escherichia coli/efeitos dos fármacos , Infecções por Escherichia coli/prevenção & controle , Humanos , Nanoestruturas/química , Nanoestruturas/ultraestrutura , Nanotubos/química , Nanotubos/ultraestrutura , Infecções Estafilocócicas/prevenção & controle , Staphylococcus aureus/efeitos dos fármacos , Telúrio/química , Titânio/químicaRESUMO
The aim of this study was to evaluate the effects of Enterococcus faecalis UGRA10 and its enterocin AS-48 against the fish pathogen Lactococcus garvieae. The minimum bactericidal concentrations of AS-48 against L. garvieae CECT 5807, 5806, and 5274 were 15.62, 15.62, and 7.81⯵g/ml respectively. In broth cultures, enterocin at 100, 50, and 25⯵g/ml reduced 108â¯CFU/ml lactococci after 2, 5, and 10â¯h, respectively. In co-cultures of UGRA10/L. garvieae at a 1/10â¯CFU/ml ratio, lactococci were eliminated after 24â¯h. Studies on UGRA10 biosafety and AS-48 toxicity in R1 cells and in rainbow trout have shown a lack of adverse effects from both the strain and bacteriocin. Trout challenged with L. garvieae and UGRA10 administered in diet 30 days before infection had a cumulative survival rate of 50% compared with 0% for control fish. Trout inoculated with the pathogen and treated by regular dipping in AS-48 baths had a survival rate of 60% after 20 days compared with that of untreated fish (0%). These results indicate the protective effect of the UGRA10 strain and the bacteriocin AS-48 against L. garvieae and the potential of these natural products as alternatives to antibiotics for controlling diseases in aquaculture.
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Bacteriocinas/farmacologia , Enterococcus faecalis/fisiologia , Doenças dos Peixes/microbiologia , Infecções por Bactérias Gram-Positivas/veterinária , Lactococcus/efeitos dos fármacos , Truta/microbiologia , Administração Oral , Ração Animal , Animais , Linhagem Celular/efeitos dos fármacos , Técnicas de Cocultura , Contenção de Riscos Biológicos , Dieta , Doenças dos Peixes/mortalidade , Doenças dos Peixes/prevenção & controle , Infecções por Bactérias Gram-Positivas/mortalidade , Infecções por Bactérias Gram-Positivas/prevenção & controle , Lactococcus/crescimento & desenvolvimento , Lactococcus/patogenicidade , Viabilidade Microbiana/efeitos dos fármacos , Probióticos/uso terapêutico , Alimentos Marinhos/microbiologia , Taxa de Sobrevida , Testes de ToxicidadeRESUMO
OBJECTIVE: Establishing the neurological localization doctrine for the contralateral hemispheric control of motor functions in the second half of the 19th century, researchers faced the challenge of recognizing false localizing signs, in particular paradoxical or ipsilateral hemiparesis (IH). Despite tremendous progress in current methods of neuroradiological and electrophysiological exploration, a complete understanding of this phenomenon has yet to be attained. METHODS: The authors researched the well-described cases of hemiparesis/hemiplegia ipsilateral to an intracranial lesion published in the scientific literature in the pre-MRI era (before 1980). A comprehensive review of the physiopathological mechanisms proposed for paradoxical hemiparesis throughout this period, as well as the pathological evidence substantiating them, is provided. RESULTS: A collection of 75 patients with hemiparesis/hemiplegia ipsilateral to the primary intracranial lesion reported between 1858 and 1979 were eligible for analysis. Most cases occurred in adults with supratentorial, slowly developing, extraparenchymatous mass lesions, such as neoplasms (38%) or chronic subdural hematomas (36%). Physiopathological theories proposed by the neurologists who investigated IH can be grouped into 4 major concepts: 1) lack of anatomical decussation of the corticospinal tract; 2) impaired functional activation of the contralateral hemisphere by the lesioned dominant hemisphere through the callosal connections; 3) Kernohan's notch phenomenon, or mechanical injury of the contralateral cerebral peduncle against the free edge of the tentorium; and 4) cerebrovascular dysfunction involving the contralateral hemisphere owing to kinking and mechanical flattening of the carotid artery contralateral to the primary intracranial lesion. CONCLUSIONS: IH represents a still underdiagnosed paradoxical neurological phenomenon. With the aid of modern neuroradiological and neurophysiological methods, Kernohan's peduncle notch mechanism has been confirmed to cause IH in many of the cases reported in recent decades. Nevertheless, alternative functional and/or vascular mechanisms must be investigated further for unexplained IH cases, in particular for transitory IH without evidence of peduncle injury. The historical theories reviewed in this paper represent a conceptual framework that may be helpful for this purpose.
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Córtex Motor , Neurocirurgia/história , Paresia/história , Tratos Piramidais , História do Século XIX , História do Século XX , Humanos , Córtex Motor/diagnóstico por imagem , Córtex Motor/fisiopatologia , Tratos Piramidais/diagnóstico por imagem , Tratos Piramidais/fisiopatologiaAssuntos
Computadores , Redes Neurais de Computação , Humanos , Análise por Conglomerados , AlgoritmosRESUMO
The heart is a muscle with high energy demands. Hence, most patients with mitochondrial disease produced by defects in the oxidative phosphorylation (OXPHOS) system are susceptible to cardiac involvement. The presentation of mitochondrial cardiomyopathy includes hypertrophic, dilated and left ventricular noncompaction, but the molecular mechanisms involved in cardiac impairment are unknown. One of the most frequent OXPHOS defects in humans frequently associated with cardiomyopathy is cytochrome c oxidase (COX) deficiency caused by mutations in COX assembly factors such as Sco1 and Sco2. To investigate the molecular mechanisms that underlie the cardiomyopathy associated with Sco deficiency, we have heart specifically interfered scox expression, the single Drosophila Sco orthologue. Cardiac-specific knockdown of scox reduces fly lifespan, and it severely compromises heart function and structure, producing dilated cardiomyopathy. Cardiomyocytes with low levels of scox have a significant reduction in COX activity and they undergo a metabolic switch from OXPHOS to glycolysis, mimicking the clinical features found in patients harbouring Sco mutations. The major cardiac defects observed are produced by a significant increase in apoptosis, which is dp53-dependent. Genetic and molecular evidence strongly suggest that dp53 is directly involved in the development of the cardiomyopathy induced by scox deficiency. Remarkably, apoptosis is enhanced in the muscle and liver of Sco2 knock-out mice, clearly suggesting that cell death is a key feature of the COX deficiencies produced by mutations in Sco genes in humans.
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Apoptose , Cardiomiopatias/enzimologia , Modelos Animais de Doenças , Proteínas de Drosophila/metabolismo , Drosophila/metabolismo , Miocárdio/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Animais , Cardiomiopatias/genética , Cardiomiopatias/metabolismo , Cardiomiopatias/fisiopatologia , Drosophila/enzimologia , Drosophila/genética , Proteínas de Drosophila/genética , Complexo IV da Cadeia de Transporte de Elétrons/genética , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Feminino , Técnicas de Silenciamento de Genes , Humanos , Masculino , Proteína Supressora de Tumor p53/genéticaRESUMO
Hepatocellular carcinoma is one of the most common cancers, and approximately 80% develop from cirrhotic livers. We have previously shown that the aspartate salt of adenosine prevents and reverses carbon tetrachloride-induced liver fibrosis in rats. Considering the hepatoprotective role of this adenosine derivative in fibrogenesis, we were interested in evaluating its effect in a hepatocarcinogenesis model induced by diethylnitrosamine in rats, where multinodular cancer is preceded by cirrhosis. Rats were injected with diethylnitrosamine for 12 weeks to induce cirrhosis and for 16 weeks to induce hepatocarcinogenesis. Groups of rats were treated with aspartate salt of adenosine from the beginning of carcinogen administration for 12 or 18 weeks total, and another group received the compound from weeks 12 to 18. Fibrogenesis was estimated and the proportion of preneoplastic nodules and tumors was measured. The apoptotic and proliferation rates in liver tissues were evaluated, as well as the expression of cell signaling and cell cycle proteins participating in hepatocarcinogenesis. The adenosine derivative treatment reduced diethylnitrosamine-induced collagen expression and decreased the proportion of nodules positive for the tumor marker γ-glutamyl transferase. This compound down-regulated the expression of thymidylate synthase and hepatocyte growth factor, and augmented the protein level of the cell cycle inhibitor p27; these effects could be part of its chemopreventive mechanism. These findings suggest a hepatoprotective role of aspartate salt of adenosine that could be used as a therapeutic compound in the prevention of liver tumorigenesis as described earlier for hepatic fibrosis.
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Adenosina/análogos & derivados , Cirrose Hepática/complicações , Cirrose Hepática/tratamento farmacológico , Neoplasias Hepáticas Experimentais/etiologia , Neoplasias Hepáticas Experimentais/prevenção & controle , Adenosina/farmacologia , Animais , Anticarcinógenos/farmacologia , Dietilnitrosamina , Modelos Animais de Doenças , Cirrose Hepática/induzido quimicamente , Masculino , Ratos , Ratos WistarRESUMO
INTRODUCTION: Our aim was to characterize a stepwise approach in cavotricuspid isthmus ablation for typical atrial flutter in a prospective, noncrossover randomized study. METHODS: One hundred and fifty patients referred for cavotricuspid isthmus (CTI)-dependent atrial flutter ablation were randomized to undergo an ablation with an 8-mm-tip catheter (group 1), a 3.5-mm open irrigation-tip catheter (group 2), and a 3.5-mm open irrigation porous-tip catheter (group 3). A stepwise approach was performed, changing the ablation site from medial to septal aspects of the CTI, in case it was not effective without crossover between catheters. RESULTS: CTI block was achieved in all the patients using only one catheter. There was a 68% efficacy in group 1, 40% in group 2, and 28% in group 3 to achieve CTI block within 10 minutes (P = 0.001) and 96%, 70%, and 70% in groups 1, 2, and 3, respectively, within 20 minutes (P = 0.002) of radiofrequency ablation. The 8-mm catheter was also faster in fluoroscopy time and CTI block time. There were no differences in efficiency in the both irrigated catheters. There were no significant differences in complications among three catheters. CONCLUSIONS: With this stepwise approach, it is possible to achieve CTI block in all cases, using a single catheter without crossover, with good times of procedure and with a low complication rate. The 8-mm solid catheter is faster than the other irrigated-tip catheters. The 3.5-mm open irrigation porous-tip catheter is as effective and safe as the conventional irrigated-tip catheter.
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Flutter Atrial/cirurgia , Ablação por Cateter/instrumentação , Ablação por Cateter/métodos , Valva Tricúspide/cirurgia , Veia Cava Inferior/cirurgia , Idoso , Catéteres , Desenho de Equipamento , Feminino , Humanos , Masculino , Estudos ProspectivosRESUMO
BACKGROUND: It has been described that many Charcot-Marie-Tooth syndrome type 2 patients are affected by a very disabling type of tremor syndrome, the pathophysiology of which remains unclear. Deep brain stimulation (DBS) has been successfully applied to treat most types of tremors by implanting electrodes in the ventral intermediate nucleus of the thalamus (Vim). METHODS: We used DBS applied to the Vim in 2 patients with severe axonal inherited polyneuropathies who developed a disabling tremor. RESULTS: Both patients responded positively to stimulation, with a marked reduction of the tremor and with an improvement of their quality of life. CONCLUSION: We report 2 cases of tremor associated with a hereditary neuropathy with a good response to DBS.
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Doença de Charcot-Marie-Tooth/cirurgia , Estimulação Encefálica Profunda/métodos , Qualidade de Vida , Tálamo/cirurgia , Tremor/cirurgia , Doença de Charcot-Marie-Tooth/complicações , Doença de Charcot-Marie-Tooth/fisiopatologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Tempo , Resultado do Tratamento , Tremor/etiologia , Tremor/fisiopatologiaRESUMO
Fast and slow TnI are co-expressed in E11.5 embryos, and fast TnI is present from the very beginning of myogenesis. A novel green fluorescent protein (GFP) reporter mouse lines (FastTnI/GFP lines) that carry the primary and secondary enhancer elements of the mouse fast troponin I (fast TnI), in which reporter expression correlates precisely with distribution of the endogenous fTnI protein was generated. Using the FastTnI/GFP mouse model, we characterized the early myogenic events in mice, analyzing the migration of GFP+ myoblasts, and the formation of primary and secondary myotubes in transgenic embryos. Interestingly, we found that the two contractile fast and slow isoforms of TnI are expressed during the migration of myoblasts from the somites to the limbs and body wall, suggesting that both participate in these events. Since no sarcomeres are present in myoblasts, we speculate that the function of fast TnI in early myogenesis is, like Myosin and Tropomyosin, to participate in cell movement during the initial myogenic stages. genesis
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Rastreamento de Células/métodos , Regulação da Expressão Gênica no Desenvolvimento , Mioblastos/metabolismo , Troponina I/genética , Animais , Extremidades/embriologia , Genes Reporter , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Imuno-Histoquímica , Hibridização In Situ , Camundongos , Camundongos Transgênicos , Modelos Animais , Desenvolvimento Muscular/genética , Miosinas/genética , Miosinas/metabolismo , Isoformas de Proteínas , Tropomiosina/genética , Tropomiosina/metabolismo , Troponina I/metabolismoRESUMO
AIMS: To assess sensory neuropathy development after severe COVID-19. METHODS: Patients with severe COVID-19 underwent assessment of neuropathic symptoms, tendon reflexes, and quantitative sensory testing to evaluate vibration (VPT), cold (CPT), warm (WPT) and heat perception thresholds (HPT) within 1-3 weeks of admission and after 1-year. RESULTS: 32 participants with severe COVID-19 aged 68.6 ± 12.4 (18.8 % diabetes) were assessed. At baseline, numbness and neuropathic pain were present in 56.3 % and 43.8 % of participants, respectively. On the feet, VPT, WPT, and HPT were abnormal in 81.3 %, CPT was abnormal in 50.0 % and HPT on the face was abnormal in 12.5 % of patients. At 1-year follow-up, the prevalence of abnormal VPT (81.3 % vs 50.0 %, P < 0.01), WPT (81.3 % vs 43.8 %, P < 0.01), and HPT (81.3 % vs 50.0 %, P < 0.01) decreased, with no change in CPT (P = 0.21) on the feet or HPT on the face (P = 1.0). Only participants without diabetes recovered from an abnormal VPT, CPT, and WPT. Patients with long-COVID (37.5 %) had comparable baseline VPT, WPT and CPT with those without long-COVID (P = 0.07-0.69). CONCLUSIONS: Severe COVID-19 is associated with abnormal vibration and thermal thresholds which are sustained for up to 1 year in patients with diabetes. Abnormal sensory thresholds have no association with long-COVID development.
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COVID-19 , Diabetes Mellitus , Neuropatias Diabéticas , Neuralgia , Humanos , Síndrome de COVID-19 Pós-Aguda , COVID-19/complicações , Limiar Sensorial , Neuralgia/diagnóstico , Neuralgia/etiologia , Vibração , Neuropatias Diabéticas/diagnóstico , Neuropatias Diabéticas/etiologiaRESUMO
The influence of surface morphology and the oxidation state on the electrocatalytic activity of nanostructured electrodes is well recognized, yet disentangling their individual roles in specific reactions remains challenging. Here, we investigated the electrooxidation of sulfite ions in an alkaline environment using cyclic voltammetry on copper oxide nanostructured electrodes with different oxidation states and morphologies but with similar active areas. To this aim, we synthesized nanostructured Cu films made of nanoparticles or nanorods on top of glassy carbon electrodes. Our findings showed an enhanced sensitivity and a lower detection threshold when utilizing Cu(I) over Cu(II). Density functional theory-based thermochemical analysis revealed the underlying oxidation mechanism, indicating that while the energy gain associated with the process is comparable for both oxide surfaces, the desorption energy barrier for the resulting sulfate molecules is three times higher on Cu(II). This becomes the limiting step of the reaction kinetics and diminishes the overall electrooxidation efficiency. Our proposed mechanism relies on the tautomerization of hydroxyl groups confined on the surface of Cu-based electrodes. This mechanism might be applicable to electrochemical reactions involving other sulfur compounds that hold technological significance.
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Cerebrovascular damage from small vessel disease (SVD) occurs in healthy and pathological aging. SVD markers, such as white matter hyperintensities (WMH), are commonly found in individuals over 60 and increase in prevalence with age. WMHs are detectable on standard MRI by adhering to the STRIVE criteria. Currently, visual assessment scales are used in clinical and research scenarios but is time-consuming and has rater variability, limiting its practicality. Addressing this issue, our study aimed to determine the most precise WMH segmentation software, offering insights into methodology and usability to balance clinical precision with practical application. This study employed a dataset comprising T1, FLAIR, and DWI images from 300 cognitively healthy older adults. WMHs in this cohort were evaluated using four automated neuroimaging tools: Lesion Prediction Algorithm (LPA) and Lesion Growth Algorithm (LGA) from Lesion Segmentation Tool (LST), Sequence Adaptive Multimodal Segmentation (SAMSEG), and Brain Intensity Abnormalities Classification Algorithm (BIANCA). Additionally, clinicians manually segmented WMHs in a subsample of 45 participants to establish a gold standard. The study assessed correlations with the Fazekas scale, algorithm performance, and the influence of WMH volume on reliability. Results indicated that supervised algorithms were superior, particularly in detecting small WMHs, and can improve their consistency when used in parallel with unsupervised tools. The research also proposed a biomarker for moderate vascular damage, derived from the top 95th percentile of WMH volume in healthy individuals aged 50 to 60. This biomarker effectively differentiated subgroups within the cohort, correlating with variations in brain structure and behavior.
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White matter hyperintensities of vascular origin (WMH) are commonly found in individuals over 60 and increase in prevalence with age. The significance of WMH is well-documented, with strong associations with cognitive impairment, risk of stroke, mental health, and brain structure deterioration. Consequently, careful monitoring is crucial for the early identification and management of individuals at risk. Luckily, WMH are detectable and quantifiable on standard MRI through visual assessment scales, but it is time-consuming and has high rater variability. Addressing this issue, the main aim of our study is to decipher the utility of quantitative measures of WMH, assessed with automatic tools, in establishing risk profiles for cerebrovascular deterioration. For this purpose, first, we work to determine the most precise WMH segmentation open access tool compared to clinician manual segmentations (LST-LPA, LST-LGA, SAMSEG, and BIANCA), offering insights into methodology and usability to balance clinical precision with practical application. The results indicated that supervised algorithms (LST-LPA and BIANCA) were superior, particularly in detecting small WMH, and can improve their consistency when used in parallel with unsupervised tools (LST-LGA and SAMSEG). Additionally, to investigate the behavior and real clinical utility of these tools, we tested them in a real-world scenario (N = 300; age > 50 y.o. and MMSE > 26), proposing an imaging biomarker for moderate vascular damage. The results confirmed its capacity to effectively identify individuals at risk comparing the cognitive and brain structural profiles of cognitively healthy adults above and below the resulted threshold.
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The main objective was to evaluate structural and functional connectivity correlates of fatigue in post-COVID syndrome, and to investigate the relationships with an objective measure of mental fatigue and with subjective cognitive complaints. One-hundred and twenty-nine patients were recruited after 14.79 ± 7.17 months. Patients were evaluated with fatigue, neuropsychological, and subjective cognitive complaints assessments. Structural and functional magnetic resonance imaging were acquired, and functional connectivity, white matter diffusivity and grey matter volume were evaluated. Fatigue was present in 86 % of patients, and was highly correlated to subjective cognitive complaints. Fatigue was associated with structural and functional connectivity mostly in frontal areas but also temporal, and cerebellar areas, showing mental fatigue different pattern of functional connectivity correlates compared to physical fatigue. White matter diffusivity correlates were similar in fatigue and subjective cognitive complaints, located in the forceps minor, anterior corona radiata and anterior cingulum. Findings confirm that fatigue in post-COVID syndrome is related to cerebral connectivity patterns, evidencing its brain substrates. Moreover, results highlight the relationship between fatigue and subjective cognitive complaints. These findings point out the relevance of the multidisciplinary assessment of post-COVID syndrome patients with subjective cognitive complaints, in order to unravel the symptomatology beneath the patient's complaints.
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PURPOSE: Intraoperative neurophysiologic monitoring in thoracoabdominal aneurysms (TAAA) is essential to avoid intraoperative spinal cord injury). Motor and somatosensory evoked potentials may be considered intraoperative tools for detecting spinal cord injury. H-reflex is a well-known neurophysiologic technique to evaluate L5-S1 root. Current evidence supports the observation that H-reflex changes may occur with spinal cord damage as high as the cervical level. This study aimed to evaluate the usefulness of the H-reflex in these surgeries. METHODS: The use of intraoperative H-reflex in TAAA monitoring was evaluated in 12 patients undergoing open or endovascular repair of TAAA for a period of four years (2016-2020) using somatosensory evoked potentials (SSEPs) and transcranial motor evoked potentials (TcMEPs) and bilateral H-reflex. RESULTS: Six neurophysiologic alarms were recorded in five of the 12 patients. Summarizing the neurophysiologic changes of our series, we considered a peripheral change when we detected a unilateral loss of SSEPs, TcMEPs, and H-reflex. Instead, we assumed a central change when we detected a unilateral or bilateral loss of TcMEPs and H-reflex with normal SSEPs, which we considered a sign of spinal cord ischemia. Interestingly H-reflex always changed significantly in combination with TcMEPs in the same fashion. CONCLUSIONS: According to our series, H-reflex can detect intraoperative changes with the same sensitivity as TcMEPs in TAAA surgeries. With the support of other techniques, it can be useful to localize the origin of the lesion (peripheral or central spinal cord), to help in surgical decision-making to avoid postoperative neurologic damage. Based on our results, we recommend the systematic use of H-reflex in TAAA surgeries.