Effect of aluminum oxide on the structure and conduction behaviors of silver borate glasses

ABSTRACT. The current study focuses on glass preparation and characterization in the glass system of chemical formula xAl2O3 (35-x) Ag2O.65B2O3 (0≤x≤35 mol%), where Ag2O is replaced with Al2O3. To examine a wide range of both structure and morphology of the prepared glasses, nuclear magnetic resonance (NMR) of 27Al nuclei, X-ray diffraction (XRD) spectroscopy, and transmission electron microscopy (TEM) are used. In Al2O3-rich glass, the well-formed AlO6, AlO5, and AlO4 structural groups are the well-formed units. In samples of (20 and 30 mol % Al2O3), tetrahedral AlO4 and traces from AlO6 units could be detected. At lower concentrations of Al2O3 (10 mol%), the dominant forming unit is only AlO4 groups containing non-bridging oxygen bonds (NBO). The XRD spectra confirm the amorphous nature of the glasses of Al2O3 ˂20 mol% while glasses of higher Al2O3 concentrations contain crystalline Ag2Al2B2O7 formed due to the higher oxygen packaging of the mixed AlO5 and AlO4 compared with that of glasses containing only AlO4 species only. The morphology of crystalline units is confirmed from TEM to differ from that of an amorphous composition. The increase of activation energy and the hardness number of the glasses led to an increase in the durability of the investigated glasses.   KEY WORDS: Aluminum borate glass, NMR, Coordination of aluminum atom, Conductivity, Crystallization process Bull. Chem. Soc. Ethiop. 2022, 36(3), 597-606.                                                               DOI: https://dx.doi.org/10.4314/bcse.v36i3.9                                                       &nbsp

Heterocyclic synthesis with nitriles: synthesis of pyrazolopyrimidine and pyrazolopyridine derivatives

The reaction of N1-substituted-5-amino-4-cyanopyrazoles with malononitrile and diethylmalonate occurs with formation of 6-substituted pyrazolo[3,4-d]pyrimidines, and pyrazolo[3,4-b]pyridines respectively. The structures of the products and conceivable mechanisms are discussed.Fundação para a Ciência e Tecnologia - SFRH/BPD/31490/2006Fundo Europeu de Desenvolvimento Regional (FEDER) - POCTI-SFA-3-68

Synthesis of 3-indolylazoles and meridianin derivatives from indolyl enaminonitriles

The reaction of indole derivatives with cyanoacetic acid followed by treatment with DMFDMA gave the intermediate indolyl enaminonitriles (3). Further reaction with aminoguanidine yielded 5´-cyanomeridianin analogues (4). The same intermediate reacted with p-methoxyphenylhydrazine to give the pyrazolyl derivative (8). Treatment of (2E)-3-dimethylamino-2-(1H-indol-3-yl)-propenoate (3a) with hydroxylamine hydrochloride in basic medium afforded (5-amino-isoxazol-4-yl)-(1H-indol-3-yl)-methanone (5) and the acrylic acid derivative (6) after a short or a long heating, respectively. Unequivocal structural elucidation of the latter compound was achieved from single-crystal X-ray diffraction studies.Fundação para a Ciência e a Tecnologia (FCT) - SFRH/BPD/31490/2006FEDER - REEQ/ 630/QUI/200

RADON CONCENTRATION AND RADON EXHALATION RATE FOR GRANITE ROCKS, CENTRAL EASTERN DESERT, EGYPT

The aim of the present work deals with measuring 222Rn Concentration (Bq/m3), 222Rn exhalation rate, annual effective dose (indoors and outdoors) and excess lifetime cancer risk (RRLC %), for basement rock samples from central Eastern Desert of Egypt using Alpha GUARD

Anticancer effects of punicalagin and 5-fluorouracil on laryngeal squamous cell carcinoma: an <i>in vitro</i> study

The purpose of this study was to assess the apoptotic effects of punicalagin alone and in combination with 5-fluorouracil (5-FU) on laryngeal squamous cell carcinoma (Hep-2) cell line. Hep-2 cells were cultured and divided into four groups: Group 1 received no therapy and served as control, Group 2 received 5-FU only, Group 3 received punicalagin only, and Group 4 received a combination of 5-FU and punicalagin. After 48 hours of incubation, cellular changes were examined under an inverted microscope. The methyl thiazolyl tetrazolium assay, caspase-3 gene level, and vascular endothelial growth factor (VEGF) level were assessed. The control group showed the highest mean value of cancer cell proliferation rate (1.595±0.58), followed by the punicalagin group (1.263±0.447), then the 5-FU group (0.827±0.256), while the combination group showed the lowest proliferation rate (0.253±0.111). The combination group showed the highest mean value of caspase-3 concentration (3.177±0.736), followed by the 5-FU group (1.830±0.646), and punicalagin group (0.741±0.302), while the control group showed the lowest mean value (0.359±0.117). Regarding VEGF levels, the control group had a statistically significant higher mean value, followed by the punicalagin and 5-FU groups, and finally, the combination group which showed the lowest value. Punicalagin exerts an anticancer effect through anti-proliferative action and induction of apoptosis on Hep-2 cell line. Combining punicalagin with 5-FU potentiates its anti-proliferative, apoptotic, and anti-angiogenic actions. It, further, helps in mitigating the putative side effects of 5-FU by reducing the dose required for its therapeutic effects

Comparative analysis of gas atomised and recycled 316L stainless steel powders for Binder Jetting

In our work, we investigate the suitability of a 316L stainless steel powder from scrap metal recycling for binder jetting and the results are compared to those obtained for a gas atomised feedstock. First, the main morphological features of the particles, in particular sphericity and size distribution, are measured by static image granulometry and scanning electron microscopy. Then, the dispensing rate and the printer deposition parameters are optimised to obtain a smooth and homogeneous powder bed. After printing, the building box is cured at 180 °C to consolidate the green components, whose density and geometrical accuracy are determined by caliper measurement. Finally, the microstructural and mechanical properties of the vacuum sintered specimens are studied. Phase composition is determined by x-ray diffraction and microscopy, with specific attention to δ-ferrite formation at the grain boundary. Hardness is evaluated by Vickers micro-indentation and compared to typical properties of 316L by conventional manufacturing