Spark plasma sintering consolidation of Bi1.65Pb0.35Sr2Ca2Cu3010+δ ceramic samples

Pre-reacted powders of (Bi-Pb)2Sr2Ca2Cu3O10+δ (Bi-2223) were consolidated by using the spark plasma sintering (SPS) technique under vacuum and at different consolidated temperatures TD. We have found that the transport properties of SPS samples depend on their oxygen content because the SPS process is performed under vacuum. From these results we have inferred that SPS samples are oxygen deficient and that a post-annealing treatment, performed in air for a brief time interval, is needed to restore such a deficiency. Measurements of temperature dependence of the thermal conductivity, κ(T), were performed in all SPS samples including a reference sample sintered at 845 °C in air. The results indicate that the electronic contribution to the thermal conductivity in all samples is very low. Values of κ were found to be higher in SPS samples mostly because of their high volume density of ~ 5.7 g/cm3. We have also performed measurements of the critical current density as a function of the applied magnetic field, Jc(Ba). All samples display a clear Josephson-like behavior and low values of the superconducting critical current density at zero applied magnetic field. The experimental results indicate that the oxygen deficiency in SPS samples is marked near the grain boundaries. This suggests the occurrence of grains with core-shell morphology, where the width of the shell is consolidation temperature dependent

Process optimization of microwave-assisted extraction of bioactive molecules from avocado seeds

Avocado seeds are an agroindustrial residue produced largely by avocado processing industries, which is accumulated in high quantities because it has low reuse due to its poor revalorization. The optimization of Microwave-Assisted Extraction (MAE) of bioactive compounds with high antioxidant capacity from avocado seeds were studied in the present work for the first time. Applying two experimental designs, using acetone 70 % and ethanol, the optimal conditions of extraction were found: 72.18 °C for 19.01 min and 71.64 °C for 14.69 min with 58.51 % of ethanol, respectively, to obtain extracts with highest antioxidant activity. The optimized extracts obtained with acetone and ethanol showed a high polyphenolic content (307.09 ± 14.16 and 254.40 ± 16.36 mg GAE/g extract) and high antioxidant activity measured by DPPH (266.56 ± 2.76 and 221.69 ± 20.12 mg ET/g extract), ABTS (607.28 ± 4.71 and 516.34 ± 11.81 mg ET/g extract) and ORAC (475.55 ± 47.82 and 495.25 ± 14.52 mg ET/g extract), proving MAE as a better technique than those previously reported for avocado seeds. Fiber residues obtained after MAE showed bonded phenolics compounds with relevant antioxidant activity, those obtained with ethanol. HPLC-ESI-MS analysis showed the presence of 20 different identified compounds, including phenolic acids, procyanidins dimer B and trimer A and B in different isomers forms, catechin, epicatechin and perseitol. MAE is a green, energy efficient and rapid tool for extractions of bioactive components from avocado seedswithout affecting their antioxidant activities representing an attractive alternative protocol in traditional herbal industry and medicine.N/

Familial progressive sensorineural deafness is mainly due to the mtDNA A1555G mutation and is enhanced by treatment of aminoglycosides.

Hearing loss involves both genetic and environmental factors. A mutation (A1555G) in the mtDNA has been associated with aminoglycoside-induced and nonsyndromic sensorineural deafness. The pathological significance of this mutation in Caucasoid families has not been established, and its relationship with antibiotic treatment is not well understood. We studied 70 Spanish families with sensorineural deafness (36 congenital and 34 late onset) for the mtDNA A1555G mutation. The A1555G mutation was found in 19 families with maternally transmitted deafness but not in the other 51 families or in 200 control subjects. In 12 families all the patients with the A1555G mutation who received aminoglycosides became deaf, representing 30.3% of the deaf patients in these families. None of the deaf patients from seven other families received aminoglycosides. Overall, only 17.7% of the patients with deafness and the A1555G mutation had been treated with aminoglycosides. The age at onset of deafness was lower (median age 5 years, range 1-52 years) in those treated with aminoglycosides than in those who did not receive antibiotics (median age 20 years, range 1-65 years) (P < .001). The mtDNA of these families belongs to haplotypes common in Europeans. These data indicate that the A1555G mutation accounts for a large proportion of the Spanish families with late-onset sensorineural deafness, that the A1555G mutation has an age-dependent penetrance for deafness (enhanced by treatment with aminoglycosides), and that mtDNA backgrounds probably do not play a major role in disease expression

Connexin-26 mutations in sporadic and inherited sensorineural deafness.

BACKGROUND: Hearing impairment affects one infant in 1000 and 4% of people aged younger than 45 years. Congenital deafness is inherited or apparently sporadic. We have shown previously that DFNB1 on chromosome 13 is a major locus for recessive deafness in about 80% of Mediterranean families and that the connexin-26 gene gap junction protein beta2 (GJB2) is mutated in DFNB1 families. We investigated mutations in the GJB2 gene in familial and sporadic cases of deafness. METHODS: We obtained DNA samples from 82 families from Italy and Spain with recessive non-syndromic deafness and from 54 unrelated participants with apparently sporadic congenital deafness. We analysed the coding region of the GJB2 gene for mutations. We also tested 280 unrelated people from the general populations of Italy and Spain for the frameshift mutation 35delG. FINDINGS: 49% of participants with recessive deafness and 37% of sporadic cases had mutations in the GJB2 gene. The 35delG mutation accounted for 85% of GJB2 mutations, six other mutations accounted for 6% of alleles, and no changes in the coding region of GJB2 were detected in 9% of DFNB1 alleles. The carrier frequency of mutation 35delG among people from the general population was one in 31 (95% CI one in 19 to one in 87). INTERPRETATION: Mutations in the GJB2 gene are a major cause of inherited and apparently sporadic congenital deafness. Mutation 35delG is the most common mutation for sensorineural deafness. Identification of 35delG and other mutations in the GJB2 gene should facilitate diagnosis and counselling for the most common genetic form of deafness