Influence of cerium doping concentration on the optical properties of Ce,Mg:LuAG scintillation ceramics

Ce,Mg:LuAG scintillation ceramics with Ce dopant content ranging from 0.025?at.% to 0.3?at.% and constant 0.2?at.% Mg codoping were fabricated by solid-state reaction. The effects of Ce concentration and annealing conditions on the microstructure, optical quality and scintillation properties are studied in great details. Lattice parameters as well as the absorption, photoluminescence, radioluminescence and thermoluminescence characteristics are investigated as a function of Ce content. Both the photoluminescence and scintillation decays are measured as well in order to study re-absorption and concentration quenching processes. In addition, an enhanced positive effect of air annealing on radioluminescence intensity and light yield is put in evidence. Moreover, the role of the charge transfer absorption of Ce⁴⁺ is investigated. Thermoluminescence measurements are performed to investigate the influence of both air annealing and Ce concentration on defects acting as traps. Finally, the correlations among steady state scintillation efficiency, light yield, thermoluminescence and Ce³⁺ concentration are found and discussed.     

Comparison and effect of Cinder supported with Manganese and Lanthanum oxide for biodiesel production

In this study, comparison and effect of Cinder supported with Lanthanum and Manganese oxide as catalyst for transesterification of triglyceride to methyl ester is proposed. The reaction mechanism along with the effects of methanol to oil molar ratio, amount of catalyst to oil, reaction temperature were also discussed. Moreover reusability of catalyst, catalyst resistance toward Free Fatty Acid and water were also discussed. The results show that yield of biodiesel produced with Mn:La:Cinder catalyst was 99% at ≥150 °C in 6 h. Cinder supported with Mn shows conversion of triglycerides from soybean oil in reaction with methanol after 6 h was over 99% at 150 °C. For both catalyst 3wt% of catalyst based on oil, 24:1 methanol/oil molar ratio was reused for 7 times with regeneration. The catalysts displayed great resistance toward 2.5% water and 1% wt fatty acids.     

First report of Paralytic Shellfish Poisoning (PSP) in mussels (Mytilus galloprovincialis) from eastern Adriatic Sea (Croatia)

The chromatographic HPLC-FLD method was introduced for the first time to identify and quantitatively determine individual Paralytic Shellfish Poisoning toxins accumulated in aquacultured shellfish from Croatian coastal waters. Populations of Mediterranean mussels (Mytilus galloprovincialis) were contaminated with PSP toxins throughout January to April 2009 leading to the positive test results by Mouse Bioassay (MBA). Until 2009 there was no evidence of PSP toxins in the examined samples. For the first time an instrumental method revealed the PSP toxin profile of samples taken along the eastern Adriatic coast and identified saxitoxin (STX) as the main representative of this toxin group that may cause paralysis and death in consumers of contaminated shellfish. This phenomenon may have serious health and economic consequences. Following these potential consequences, marine biotoxins (PSP, ASP and DSP) are continuously assessed in bivalves from 25 breeding and harvesting areas along the Croatian Adriatic coast. Positive MBA results were confirmed by instrumental method in two out of three recorded samples. Saxitoxin was the dominant PSP toxin extracted from contaminated mussels within the range of 53.17-1298.17 μg g⁻¹, that contributed more than 70% to the total shellfish toxicity, followed by gonyautoxins 2 and 3 (GTX 2,3) which contributed 27% and decarbamoylsaxitoxin (dcSTX) that accounted for less than 2%, considering all stations.     

Uroporphyrinogen decarboxylase: complete human gene sequence and molecular study of three families with hepatoerythropoietic porphyria

A deficiency in uroporphyrinogen decarboxylase (UROD) enzyme activity, the fifth enzyme of the heme biosynthetic pathway, is found in patients with sporadic porphyria cutanea tarda (s-PCT), familial porphyria cutanea tarda (f-PCT), and hepatoerythropoietic porphyria (HEP). Subnormal UROD activity is due to mutations of the UROD gene in both f-PCT and HEP, but no mutations have been found in s-PCT. Genetic analysis has determined that f-PCT is transmitted as an autosomal dominant trait. In contrast, HEP, a severe form of cutaneous porphyria, is transmitted as an autosomal recessive trait. HEP is characterized by a profound deficiency of UROD activity, and the disease is usually manifest in childhood. In this study, a strategy was designed to identify alleles responsible for the HEP phenotype in three unrelated families. Mutations of UROD were identified by direct sequencing of four amplified fragments that contained the entire coding sequence of the UROD gene. Two new missense mutations were observed at the homoallelic state: P62L (proline-to-leucine substitution at codon 62) in a Portuguese family and Y311C (tyrosine-to-cysteine substitution at codon 311) in an Italian family. A third mutation, G281E, was observed in a Spanish family. This mutation has been previously described in three families from Spain and one from Tunisia. In the Spanish family described in this report, a paternal uncle of the proband developed clinically overt PCT as an adult and proved to be heterozygous for the G281E mutation. Mutant cDNAs corresponding to the P62L and Y311C changes detected in these families were created by site-directed mutagenesis. Recombinant proteins proved to have subnormal enzyme activity, and the Y311C mutant was thermolabile.     

Inhibition of Phosphodiesterase-4 in Psoriatic Arthritis and Inflammatory Bowel Diseases

Phosphodiesterases (PDEs) are a heterogeneous superfamily of enzymes which catalyze the degradation of the intracellular second messengers cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP). Among PDEs, PDE4 is the most widely studied and characterized isoenzyme. PDE4 blocking can lead to increased levels of intracellular cAMP, which results in down-regulation of inflammatory responses by reducing the expression of tumor necrosis factor (TNF), interleukin (IL)-23, IL-17, interferon-γ, while increasing regulatory cytokines, such as IL-10. Therefore, PDE4 has been explored as a therapeutic target for the treatment of different chronic inflammatory conditions such as psoriatic arthritis (PsA) and inflammatory bowel disease (IBD). PsA shares clinical, genetic, and pathogenic features with IBD such as ulcerative colitis (UC) and Crohn’s disease (CD), and enteropathic spondyloarthritis (eSpA) represent a frequent clinical evidence of the overlap between gut and joint diseases. Current therapeutic options in PsA patients and underlying UC are limited to synthetic immunosuppressants and anti-TNF. Apremilast is an oral PDE4 inhibitor approved for the treatment of active PsA patients with inadequate response to synthetic immunosuppressants. The efficacy and a good safety profile observed in randomized clinical trials with apremilast in PsA patients have been confirmed by few studies in a real-life scenario. In addition, apremilast led to significant improvement in clinical and endoscopic features in UC patients in a phase II RCT. By now there are no available data regarding its role in eSpA patients. In view of the above, the use of apremilast in eSpA patients is a route that deserves to be deepened.     

The influence of the reaction temperature on the morphology of sodium titanate 1D nanostructures and their thermal stability

We have synthesized large quantities of sodium-titanate-based nanotubes and nanoribbons with high yields under hydrothermal conditions from anatase powder in an aqueous NaOH solution. The reaction temperatures were from 95 to 195 degrees C, in steps of 20 degrees C. We observed that the morphology of the nanomaterials, which is reflected in their specific surface areas, depends strongly on the reaction temperature. For the materials synthesized in the range 95-135 degrees C and above 155 degrees C only a single morphology type was observed for the nanostructures, i.e., nanotubes and nanoribbons, respectively. In contrast, when the reaction was carried out at 155 degreesC, both nanotubes and nanoribbons were found in the product. SEM, TEM, and XRD techniques were used to determine the materials' morphological and structural properties, and the thermal stability of the materials was investigated with TGA and DSC. The largest weight loss, of approximately 25%, was observed in a temperature range from 25 up to 600 degrees C for the product obtained at 95 degrees C, probably due to the presence of unrolled titanate sheets.     

Fast Ce,Ca:LuAG scintillation ceramics for HEP: Fabrication,characterization, and computation

High-energy physics community is looking for a hard, fast, and low-cost scintillation material, and Ce:Lu₃Al₅O₁₂ (Ce:LuAG) ceramic is one of the competitive candidates. This work presents Ce,Ca:LuAG scintillation ceramics with good optical quality, and the influence of Ce and Ca concentrations on optical and scintillation properties was fully analyzed. At relatively low level of Ce concentration, the less Ca²⁺ content is needed to achieve a significant intensity increase in fast scintillation component while maintaining a relatively high light yield (LY). The introduction of only 0.1 at% Ca²⁺ could increase the LY_{0.5 μs}/LY_{3.0 μs} from 79.9% to 96.1% in Ce,Ca:LuAG ceramics of 0.1 at% Ce. First-principles investigations are further performed to reveal the tuning mechanisms of the scintillation properties of LuAG by Ce and Ca codoping. We show that the Fermi level shifts down with Ca codoping, which increases the Ce⁴⁺ content and decreases the depth of the electron traps (V_O), resulting to a faster decay. Moreover, the formation preference of Ca-V_O complexes over Ce-V_O leads to the suppression of the non-radiative decay of Ce via V_O. In summary, our study demonstrates the realization of the performance tuning of LuAG via Ce and Ca codoping.