5 research outputs found
Effect of calcination temperature on structural, optical and photocatalytic properties of calcium titanate (CaTiO3) nanoparticle
No full textIn this study, the sol–gel method was used to synthesize calcium titanate (CaTiO3) at different calcination temperatures (400–800 °C). The main objective of this work is to find, using various characterization techniques, how the calcination temperature influences the optical, structural, and photocatalytic properties of CaTiO3. According to the DTA/TGA analysis, 600 °C was the ideal calcination temperature for the synthesis of CaTiO3 nanoparticles. The photocatalytic treatment of simulated wastewater demonstrates its potential application in wastewater treatment. For all calcination temperatures, the percentage of Chemical Oxygen Demand (COD) removed after treatment was 100 % for the initial COD of 700 mg/L, more than 83 % for the initial COD of 5000 mg/L, and more than 71 % for the initial COD of 16000 mg/l
Development of Lead Free Magnetoelectric Materials for Magnetic Field Sensor applications
No full text(100-x) Na0.5Bi0.5TiO3 (NBT)-(x) NiFe2O4 (NFO)(x = 0, 20, 40, 60, 80 and 100) composites are synthesized using conventional solid state reaction method. Crystal structure studies are performed by using X-ray Diffraction technique (XRD) and the Rietveld analysis of XRD patterns confirms the co-existence of cubic (NFO) and rhombohedral (NBT) symmetry with Fd- 3m and R3c space groups, respectively. Micro-structural study reveals the formation of combination of composite phases and its inter-coupling grains. The average grain sizes and area percentage of each phase for the composites are calculated using Image J software. The Magnetisation versus Magnetic field (M-H) hysteresis loops show soft magnetic behavior of composites with variation in Saturation magnetization (MS) and Coercivity (HC). A maximum MS (34 emu/g) and low HC (15 Oe) is obtained for (80) NFO - (20) NBT composite.The Polarization – Electric field (P-E) analysis shows that the maximum saturation polarization (PS) is obtained for (60)NBT-(40)NFO sample and is attributed to the leakage current generated by conductive NFO phase. The coupling between the ferrite and ferroelectric phase is studied based on the magnetoelectric voltage coefficient(αME). The maximum (αME) of 1.82 mV/cm-Oe is obtained for (80)NBT -(20)NFO sample and this is almost 80% higher than the previously published literature on NBT-NFO composites. This can be attributed to the uniform distribution of grains with each ferroelectric phase surrounded by ferrite phase as shown in the morphological study
Survey of CT radiation doses and iodinated contrast medium administration: an international multicentric study
No full textObjective: To assess the relationship between intravenous iodinated contrast media (ICM) administration usage and radiation doses for contrast-enhanced (CE) CT of head, chest, and abdomen–pelvis (AP) in international, multicenter settings. Methods: Our international (n = 16 countries), multicenter (n = 43 sites), and cross-sectional (ConRad) study had two parts. Part 1: Redcap survey with questions on information related to CT and ICM manufacturer/brand and respective protocols. Part 2: Information on 3,258 patients (18–96 years; M:F 1654:1604) who underwent CECT for a routine head (n = 456), chest (n = 528), AP (n = 599), head CT angiography (n = 539), pulmonary embolism (n = 599), and liver CT examinations (n = 537) at 43 sites across five continents. The following information was recorded: hospital name, patient age, gender, body mass index BMI, clinical indications, scan parameters (number of scan phases, kV), IV-contrast information (concentration, volume, flow rate, and delay), and dose indices (CTDIvol and DLP). Results: Most routine chest (58.4%) and AP (68.7%) CECT exams were performed with 2–4 scan phases with fixed scan delay (chest 71.4%; AP 79.8%, liver CECT 50.7%) following ICM administration. Most sites did not change kV across different patients and scan phases; most CECT protocols were performed at 120–140 kV (83%, 1979/2685). There were no significant differences between radiation doses for non-contrast (CTDIvol 24 16–30 mGy; DLP 633 414–702 mGy·cm) and post-contrast phases (22 19–27 mGy; 648 392–694 mGy·cm) (p = 0.142). Sites that used bolus tracking for chest and AP CECT had lower CTDIvol than sites with fixed scan delays (p < 0.001). There was no correlation between BMI and CTDIvol (r2 ≤ − 0.1 to 0.1, p = 0.931). Conclusion: Our study demonstrates up to ten-fold variability in ICM injection protocols and radiation doses across different CT protocols. The study emphasizes the need for optimizing CT scanning and contrast protocols to reduce unnecessary contrast and radiation exposure to patients. Clinical relevance statement: The wide variability and lack of standardization of ICM media and radiation doses in CT protocols suggest the need for education and optimization of contrast usage and scan factors for optimizing image quality in CECT. Key Points: There is a lack of patient-centric CT protocol optimization taking into consideration mainly patients’ size. There is a lack of correlation between ICM volume and CT radiation dose across CT protocol. A ten-fold variation in iodine-load for the same CT protocol in sites suggests a lack of standardization. © The Author(s), under exclusive licence to European Society of Radiology 2024
RESTORATION OF MOTOR AND NON-MOTOR FUNCTIONS BY NEUROTROPHIC FACTORS IN NONHUMAN PRIMATES WITH DOPAMINE DEPLETION
No full textParkinson’s disease (PD) is a progressive debilitating neurodegenerative disorder characterized by resting tremor, rigidity, bradykinesia and postural instability. As the disease progresses there is a loss of dopamine (DA) neurons in the substantia nigra projecting to the various forebrain and sub-cortical regions. Current treatments for PD are unable to prevent or curtail the neurodegenerative process; so rescuing remaining dopamine in the mid-brain has been the recent focus of research examining the effectiveness of neurotrophic factors (NTFs) in the treatment of PD. In this dissertation, the ability of three novel, recently discovered NTFs to restore DA neurons and motor function in a nonhuman primate model of PD was examined. The NTFs were Cerebral Dopamine Neurotrophic Factor (CDNF) and two variants of Neurturin (NRTN), N2 and N4, that have mutations that prevent binding to heparin sulfate binding sites in the brain. These studies used the unilateral low dose (0.15 ± 0.001 mg/kg) monkey 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) model of PD to cause loss of DA neurons. Six groups of monkeys were studied: vehicle-treated (negative control), Glial Cell-line Derived Neurotropic Factor (GDNF, positive control), two groups of CDNF-treated monkeys (450 μg and 150 μg), and N2 and N4-treated groups. After MPTP, monkeys developed moderate symptoms of PD (PD rating scale score=7.9±0.5 on a scale of 0-22, p<0.001), motor dysfunction and increased daytime sleepiness. After three months of infusions, all three NTFs (150 μg CDNF, N2 and N4) significantly increased the number of DA neurons in the substantia nigra, p=0.03, and improved parkinsonian symptoms measured by rating scale, p<0.001. Most motor functions were significantly correlated with the number of DA neurons in the substantia nigra. N4 significantly improved daytime sleep duration, bouts and wake-latency (p=0.02, p=0.06 and p=0.02, respectively). In summary, CDNF, N2 and N4 trophic factors are neurorestorative to DA neurons, motor function is tightly correlated with DA neuronal number, and N4 improved the non-motor symptom of increased daytime sleepiness in this monkey PD model. These factors hold promise for clinical therapy for PD patients
