Low-temperature synthesis of bismuth titanate by modified citrate amorphous method

Bismuth titanate is a lead-free piezoelectric ceramic with outstanding properties that strictly depend on the composition and microstructure. However, bismuth-based materials are difficult to synthesize due to bismuth volatilisation that causes secondary phases and stoichiometry deviations. In this work, we propose a low-temperature chemical route, i.e. a modified amorphous citrate method, that allows a reduction of thermal treatment temperature, when compared with solid-state or other chemical routes, to obtain single-phase bismuth titanate samples. Single-phase powders with particle size under 300 nm are produced by calcination at 700 °C, and prepared into homogeneous dense pellets (density above 95%), with only isolated pores. The pellets show two distinctive features in the electrical behaviours directly associated with their mica-like microstructure: planar oriented boundaries are responsible for oxygen conduction, while the bulk is dominated by electronic conductivity. The samples show a high dielectric constant, around 200 at room temperature, while maintaining a low loss factor. The pellets also achieved a maximum polarisation of 5.85 μC/cm² and an inverse piezoelectric coefficient of 7.4 pm/V. The dielectric and piezoelectric properties obtained are comparable or superior to the state-of-the-art.     

A Sustainable Process for the Production of Varnishes Based on Pelargonic Acid Esters

This work demonstrates the possibility of using pelargonic acid (PA) esters as solvents for vegetable-based varnishes. First, PA was efficiently produced through a chemocatalytic cleavage of oleic acid, practicing an optimized scale-up of previously developed conditions. PA was then esterified with several alcohols ROH (R = Me, i-Pr, n-Bu, n-Hex, 2-ethylhexyl, and sec-octyl) and the products were formulated with a commercial rosin (Phenolic Modified Rosin Esters). Dynamic light scattering (DLS) measures and determination of rheological parameters of the corresponding varnishes disclosed their suitability for applications in offset, coldset, heatset printing inks, and coatings. Furthermore, inks obtained were used to efficiently produce preliminary industrial offset prints.     

Towards Quantitative and Standardized Serological and Neutralization Assays for COVID-19

Quantitative and robust serology assays are critical measurements underpinning global COVID-19 response to diagnostic, surveillance, and vaccine development. Here, we report a proof-of-concept approach for the development of quantitative, multiplexed flow cytometry-based serological and neutralization assays. The serology assays test the IgG and IgM against both the full-length spike antigens and the receptor binding domain (RBD) of the spike antigen. Benchmarking against an RBD-specific SARS-CoV IgG reference standard, the anti-SARS-CoV-2 RBD antibody titer was quantified in the range of 37.6 µg/mL to 31.0 ng/mL. The quantitative assays are highly specific with no correlative cross-reactivity with the spike proteins of MERS, SARS1, OC43 and HKU1 viruses. We further demonstrated good correlation between anti-RBD antibody titers and neutralizing antibody titers. The suite of serology and neutralization assays help to improve measurement confidence and are complementary and foundational for clinical and epidemiologic studies.     

Molecular Docking and Biophysical Studies for Antiproliferative Assessment of Synthetic Pyrazolo-Pyrimidinones Tethered with Hydrazide-Hydrazones

Chemotherapy represents the most applied approach to cancer treatment. Owing to the frequent onset of chemoresistance and tumor relapses, there is an urgent need to discover novel and more effective anticancer drugs. In the search for therapeutic alternatives to treat the cancer disease, a series of hybrid pyrazolo[3,4-d]pyrimidin-4(5H)-ones tethered with hydrazide-hydrazones, 5a–h, was synthesized from condensation reaction of pyrazolopyrimidinone-hydrazide 4 with a series of arylaldehydes in ethanol, in acid catalysis. In vitro assessment of antiproliferative effects against MCF-7 breast cancer cells, unveiled that 5a, 5e, 5g, and 5h were the most effective compounds of the series and exerted their cytotoxic activity through apoptosis induction and G0/G1 phase cell-cycle arrest. To explore their mechanism at a molecular level, 5a, 5e, 5g, and 5h were evaluated for their binding interactions with two well-known anticancer targets, namely the epidermal growth factor receptor (EGFR) and the G-quadruplex DNA structures. Molecular docking simulations highlighted high binding affinity of 5a, 5e, 5g, and 5h towards EGFR. Circular dichroism (CD) experiments suggested 5a as a stabilizer agent of the G-quadruplex from the Kirsten ras (KRAS) oncogene promoter. In the light of these findings, we propose the pyrazolo-pyrimidinone scaffold bearing a hydrazide-hydrazone moiety as a lead skeleton for designing novel anticancer compounds.     

Short communication: Activity of nisin,lipid bilayer fragments and cationic nisin-lipid nanoparticles against multidrug-resistant Staphylococcus spp. isolated from bovine mastitis

Staphylococci are the main etiological agents of bovine mastitis. Bacteriocins and nanoparticles have emerged as promising alternatives for the future development of antimicrobial agents. This study evaluated the activity of the bacteriocin nisin and bicelles of the synthetic cationic lipid dioctadecyldimethylammonium bromide, alone and in combination, against multidrug-resistant Staphylococcus spp. strains isolated from bovine mastitis. In summary, cationic nisin/dioctadecyldimethylammonium bromide nanoparticles are shown to be a promising alternative for the control of mastitis caused by multidrug-resistant Staphylococcus spp.     

Optimized PCR labeling in mutational and microsatellite analysis

The behavior of the dielectric properties of gelatin in the frequency range from 10(3) Hz to 10(7) Hz was investigated and compared with that of the globule protein, bovine serum albumin (BSA), desalted gelatin and BSA being used. Dielectric relaxation was observed for both the gelatin and BSA solutions. The relaxation data were fitted well by the Cole-Cole equation; the Cole-Cole parameter (beta) and the relaxation time (tau) were obtained. For the BSA solutions, tau was proportional to the solution viscosity (eta) at 40 degrees C and 25 degrees C, and the values of beta at 40 degrees C were similar to those at 25 degrees C. For gelatin solution, tau was proportional to eta at 40 degrees C, but was not proportional to eta at 25 degrees C. In addition, the values of beta at 25 degrees C were smaller than those at 40 degrees C. These results indicate that the rotation of gelatin and/or polarization of submolecular groups in the coil state greatly contributed to the dielectric relaxation at 40 degrees C; on the other hand, the formation of cross-linking junctions consisting of helix structures would have affected the dielectric relaxation at 25 degrees C.     

A community-based programme to provide prompt and adequate treatment of presumptive malaria in children

The distribution of gamma delta-T cells (gamma delta-TCR positive cells) in nasal mucosa and polyps was studied in patients with nasal allergy and non-allergic patients. The biopsy specimens from the inferior turbinate and resected polyps were frozen at -70 degrees C and sliced at a thickness of 4 microns with a cryostat. Monoclonal antibodies (CD3 and TCR-gamma delta-1) and the Labelled Streptavidin Biotin method were used to detect T lymphocytes and gamma delta-T cells. The results were as follows: 1) The rate of gamma delta-T cells in the epithelium is higher than that in the lamina propria in patients with nasal allergy. 2) In non-allergic patients, on the other hand, the rate of gamma delta-T cells was almost the same in these layers. 3) The distribution of gamma delta-T cells in nasal polyps was uniform and their rate was relatively high. It has been reported that gamma delta-T cells can recognize a stress antigen such as heat shock protein. These cells are thought to play an important role in non-specific immunoreactions. This study suggests that gamma delta-T cells in the nasal mucosa play an important role also in specific immunoreactions.     

A limited-streamer tube electron detector with high rejection power against pions

The problem of detecting electrons in the 0.5–4.0 GeV energy range, in the presence of a high pion background, has been studied using a new type of electromagnetic shower detector. Its structural properties and the main parameters are given, together with the basic results in terms of energy resolution and of rejection power against pion background. The optimization of this new instrument gives a pion rejection power of ～ 6 × 10^?4 for energy ? 1.2 GeV.     

Alterations of microsatellites in neurofibromas of von Recklinghausen's disease

von Recklinghausen's disease, or type I neurofibromatosis, a common familial tumor syndrome, is characterized by the occurrence of multiple benign neoplasms of nerve sheath cells. The disease is caused by germ-line mutations of the NF1 gene, which encodes a member of the GTPase-activating superfamily of Ras regulatory proteins. We analyzed 5 dinucleotide repeat loci in DNAs from neurofibromas and matched normal skin from 16 NF1 patients. Eight cases (50%) manifested microsatellite alterations. Expansions or compressions of dinucleotide repeats were observed at one locus in four cases and at two loci in one case. Banding patterns compatible with the loss of a microsatellite allele were observed in four cases, including one that also presented microsatellite instability. The surprisingly high frequency of microsatellite alterations suggests that the NF1 gene or another gene(s) contributing to the pathogenesis of neurofibromas might be directly or indirectly implicated in the control of genomic integrity.