- Research Article
- 10.1007/s10909-025-03298-z
Magnetocaloric Effect and Thermodynamic Properties of Trapped Polarons in 2D Monolayers Transition Metal Dichalcogenides
- May 30, 2025
- Journal of Low Temperature Physics
- J V Nguepnang + 6 more +6
Publications from 2021 to 2026
Showing 9 of 9 papers
Magnetocaloric Effect and Thermodynamic Properties of Trapped Polarons in 2D Monolayers Transition Metal Dichalcogenides
Antihyperglycemic and Antioxidative Stress Effects of Erythrophleum africanum (Fabaceae) Trunk Bark Powder Fractions on High-Calorie Diet-Induced Type 2 Diabetes in Rats.
Diabetes mellitus is a persistent and chronic metabolic disease characterized by high blood glucose levels. The aim of this work was to evaluate the antihyperglycemic and antioxidative stress effects of Erythrophyllum africanum trunk bark powder fractions in diabetes-induced rats. 30 male rats subdivided into 6 groups of five rats each received daily a sweetened hypercaloric diet supplemented with sucrose (4 g/kg bw), except for the normal control, which received a normal diet. Normal and diabetic controls subsequently received distilled water (10 mL/kg bw per os), the positive control received metformin (20 mg/kg bw per os) and the test rats received powder fractions (≤ 50 μm ≤ 50-120 μm) or unsieved powder of E. africanum (300 mg/kg bw per os) for 7 weeks. Dexamethasone (0.2 mg/kg) was administered intraperitoneally once a week from the third week, except for the normal control, which received saline. Fasting blood glucose, lipid profile, and biochemical parameters of oxidative stress were assessed during and at the end of treatment. Blood glucose levels of the animals at the 7th week were 0.92 ± 0.03, 1.52 ± 0.08, 0.78 ± 0.04, 0.77 ± 0.03, 1.13 ± 0.03, and 0.40 ± 0.01 g/L in the normal control, diabetic control, metformin-treated animals, ≤ 50 μm fraction, 50-120 μm fraction, and unsieved powder, respectively. Powder fraction ≤ 50 μm significantly improved (p < 0.01) the lipid profile (decrease in triglyceride and LDL cholesterol levels, an increase in HDL cholesterol levels) by reducing the atherogenic index. E. africanum has antihyperglycemic and antioxidative stress effects and would be less toxic to the liver and kidneys. The fine powder (≤ 50 μm) of E. africanum could be used as a food additive to prevent the occurrence of diabetes in vulnerable patients.
Read moreSemaphorin 7a is protective through immune modulation during acetaminophen-induced liver injury
Background and AimAcetaminophen (APAP) induced acute liver injury (ALI), the leading cause acute liver failure in the western world, has limited treatment options. APAP toxicity results in massive hepatic necrosis and secondary infiltrating monocytes and neutrophils, which contribute to pathogenesis. Semaphorin 7a (Sema7a), a chemoattractant and modulator of monocytes and neutrophils, is a potential therapeutic target in other conditions, but its role in APAP-ALI is unexplored.MethodsWild-type (WT) and Sema7a knockout (KO) mice were examined during APAP-ALI. Serum liver function tests, histological analysis and cellular localisation of Sema7a and its receptors, Plexin C1 and Integrin β1, were examined. Serum cytokines were quantified, tissue macrophages and neutrophils were localised, and in vivo phenotype, including phagocytosis, was assessed by immunohistochemistry and flow cytometry.ResultsSema7a was expressed by HNF4α + peri-necrotic hepatocytes circumferentially during APAP-ALI injury phases, and serum concentrations were increased, and correlated with hepatic injury. Sema7a KO mice had increased circulating inflammatory cytokines and significantly less hepatic F4/80 + macrophages, a cell type required for hepatic repair. Sema7a KO mice had higher necrotic area neutrophils, and increased neutrophil chemoattractant CXCL1. Without Sema7a expression, mice displayed increased necrosis and liver injury markers compared to Sema7a WT mice. Without peri-necrotic hepatocyte Sema7a expression, we also identified increased cell death and hepatic cellular stress outside of necrosis.ConclusionWe have identified a novel protective role of Sema7a during injury phases of APAP-ALI. Without peri-necrotic hepatocyte Sema7a expression and secretion, there is increased inflammation, time specific worsened hepatic necrosis and increased hepatic cell stress and death outside of the necrotic zone.Graphical
Read moreRepeated episodes of postictal hypoxia are a mechanism for interictal cognitive impairments
Comorbidities during the period between seizures present a significant challenge for individuals with epilepsy. Despite their clinical relevance, the pathophysiology of the interictal symptomatology is largely unknown. Postictal severe hypoxia (PIH) in those brain regions participating in the seizure has been indicated as a mechanism underlying several negative postictal manifestations. It is unknown how repeated episodes of PIH affect interictal symptoms in epilepsy. Using a rat model, we observed that repeated seizures consistently induced episodes of PIH that become increasingly severe with each seizure occurrence. Additionally, recurrent seizure activity led to decreased levels of oxygen in the hippocampus during the interictal period. However, these reductions were prevented when we repeatedly blocked PIH using either the COX-inhibitor acetaminophen or the L-type calcium channel antagonist nifedipine. Moreover, we found that interictal cognitive deficits caused by seizures were completely alleviated by repeated attenuation of PIH events. Lastly, mitochondrial dysfunction may contribute to the observed pathological outcomes during the interictal period. These findings provide evidence that seizure-induced hypoxia may play a crucial role in several aspects of epilepsy. Consequently, developing and implementing treatments that specifically target and prevent PIH could potentially offer significant benefits for individuals with refractory epilepsy.
Read morePhytochemical Analysis, Antifungal, and Antioxidant Properties of Two Herbs (Tristemma mauritianum and Crassocephalum bougheyanum) and One Tree (Lavigeria macrocarpa) Species
Phytochemicals present in medicinal plants (herbs, shrubs, and trees) are endowed with high antimicrobial and antioxidant properties. The aim of this work was to study the chemical composition, antioxidant, and antifungal activities of Tristemma mauritianum, Crassocephalum bougheyanum, and Lavigeria macrocarpa. Chemical composition of the plant extracts was determined using standard methods. The antioxidant activities were performed using 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP), nitric oxide (NO), and hydroxyl (OH) scavenging assays. The antifungal activity of plant extracts and their combinations with antifungals was evaluated against eleven Candida spp. using the broth microdilution method by determining the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC). The quantitative chemical analysis of the extracts of T. mauritianum, L. macrocarpa, and C. bougheyanum showed that they contain phenols, tannins, and flavonoids that vary according to the plant species and extracts. All the plant extracts presented promising antifungal (MIC = 64–2048 µg/mL) and antioxidant activities. The extract of T. mauritianum displayed the highest antifungal (MIC = 64–256 µg/mL) and antioxidant (IC50 = 19.052 ± 1.11 μg/mL) activities which can be explained by its high phenolic content. Interestingly, extracts of T. mauritianum, L. macrocarpa, and C. bougheyanum displayed synergistic effects (fractional inhibitory concentration index, FICI ≤ 0.5) with ketoconazole against clinical resistant isolates. The results of the present study demonstrate promising antifungal and antioxidant activities of the tested plants that are associated to their phenol, tannin, and flavonoid contents. Hence, extracts of T. mauritianum and L. macrocarpa could be deeply investigated as antifungal alone and in combination with conventional antifungal drugs to treat infections caused by Candida spp.
Read more“Pure” hepatoid tumors of the pancreas harboring CTNNB1 somatic mutations: a new entity among solid pseudopapillary neoplasms
Hepatoid tumors (HTs) represent a rare group of neoplasms that are histologically similar to hepatocellular carcinoma but arise outside the liver. The current World Health Organization classification recognizes the hepatoid morphology of pancreatic tumors only as a possible variant of pancreatic ductal adenocarcinoma (PDAC). Here, we describe two cases of “pure” HT of the pancreas showing common features and characterized by indolent biological behavior. These tumors were roundish nodules with pushing borders, hyaline globules, and pure hepatoid histology; they were diffusely positive for β-catenin and LEF1 on immunohistochemistry. At next-generation sequencing, both neoplasms harbored only one pathogenic somatic mutation that affected the CTNNB1 gene at exon 3 and showed a loss of heterozygosity on chromosomes 18 and 21. By integrating macroscopic and microscopic features, along with their molecular profiles, we advocate that such tumors represent a distinct entity from PDAC and should be considered a new variant of solid pseudopapillary neoplasms. The recognition of this new neoplastic category may have immediate implications not only for tumor taxonomy but also for clinical practice.
Read moreFPGA implementation of nonlinear equations with delay
A questionnaire to evaluate disability in osteoporotic patients with vertebral compression fractures.
Few studies have reported on the functional disability due to vertebral compression factors in osteoporosis. The Osteoporosis Functional Disability Questionnaire (OFDQ) was developed to assess disability in patients with osteoporosis and back pain due to vertebral fractures. The domains of the OFDQ include: quantitative indices of pain, a standard 20-item depression scale, 26 items relating to functional abilities, a scale of social activities, and confidence in the ability of prescribed osteoporosis treatment to reverse disability. Reliability of the OFDQ was assessed using test-retest and internal consistency methods. Criterion validity was demonstrated by correlating disability against radiographic evidence of vertebral fractures. Construct validity was demonstrated through comparisons of 81 patients with osteoporosis and fractures to 37 healthy age-matched controls. Additional evidence was found in comparing 45 of the 81 cases who were actively engaged in an exercise program with 36 cases who were sedentary. The test-retest reliabilities ranged from .76 to .93, with internal consistencies from .57 to .96. The OFDQ correlated significantly with relevant spinal pathology, and showed significant improvements in activities of daily living and socialization when active exercisers were compared to inactive patients with osteoporosis. The OFDQ is a reliable instrument which correlates well with objective measures of osteoporotic spinal damage. It is also sensitive to changes in disability brought about by participation in our aerobic exercise program. The OFDQ may be a useful adjunct to measuring outcomes in other osteoporotic treatment protocols.
Read moreComparison of portable CdTe(Cl) detectors with stationary NaI(Tl) detectors for subcutaneous 133Xe disappearance measurements.
133Xe washout measurements from locally injected depots in the subcutaneous tissue of the thigh have been performed intermittently by a NaI(Tl) detector placed 15 cm from the depot and a cadmium telluride [CdTe(Cl)] detector fixed to the skin surface above the depot. In 19 experiments, the measurements were performed during rest, before and after bicycling and during circulatory arrest during an occlusion cuff pressure of 240-250 mmHg. The disappearance rates measured by the two detector systems showed a linear correlation (r = 0.934, P less than 0.001). However, the rate constants measured by the CdTe(Cl) detector were an average of 1.48 times the values obtained by the NaI(Tl) detector during a period of 1-4 h after the injection. The coefficient of variation of the proportionality factor is 3.3%. Only the central part of the local depot area is exposed to the CdTe(Cl) detector. Using the NaI(Tl) detector and lead shielding of the peripheral or central part of the depot area, it was demonstrated that the disappearance rates obtained reflect the measuring geometries. The correction itself is therefore due to differences in the measuring geometries of the two detector types, and possibly to diffusion and convection of xenon. For quantitative determination of the subcutaneous blood flow, the disappearance rate constants determined by the CdTe(Cl) detector thus have to be corrected by division with the factor 1.48.
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