Geochemistry, mineralogy and thermal analyses of Cretaceous coals from the Benue Trough basin Nigeria: Reconnaissance assessments

The aim of this study was to synthesize, characterize, and evaluate degradation and biocompatibility of poly(lactic-co-glycolic acid) + hydroxyapatite / β-tricalcium phosphate (PLGA+HA/βTCP) scaffolds incorporating simvastatin (SIM) to verify if this biomaterial might be promising for bone tissue engineering. Samples were obtained by the solvent evaporation technique. Biphasic ceramic particles (70% HA, 30% βTCP) were added to PLGA in a ratio of 1:1. Samples with SIM received 1% (m:m) of this medication. Scaffolds were synthesized in a cylindric-shape and sterilized by ethylene oxide. For degradation analysis, samples were immersed in PBS at 37 °C under constant stirring for 7, 14, 21, and 28 days. Non-degraded samples were taken as reference. Mass variation, scanning electron microscopy, porosity analysis, Fourier transform infrared spectroscopy, differential scanning calorimetry, and thermogravimetry were performed to evaluate physico-chemical properties. Wettability and cytotoxicity tests were conducted to evaluate the biocompatibility. Microscopic images revealed the presence of macro, meso, and micropores in the polymer structure with HA/βTCP particles homogeneously dispersed. Chemical and thermal analyses presented very similar results for both PLGA+HA/βTCP and PLGA+HA/βTCP+SIM. The incorporation of simvastatin improved the hydrophilicity of scaffolds. Additionally, PLGA+HA/βTCP and PLGA+HA/βTCP+SIM scaffolds were biocompatible for osteoblasts and mesenchymal stem cells. In summary, PLGA+HA/βTCP scaffolds incorporating simvastatin presented adequate structural, chemical, thermal, and biological properties for bone tissue engineering.

Download Full-text

New Platinum (II) Ternary Complexes of Formamidine and Pyrophosphate: Synthesis, Characterization and DFT Calculations and In vitro Cytotoxicity

Combinatorial Chemistry & High Throughput Screening ◽

10.2174/1386207323666200218115700 ◽

2020 ◽

Vol 23 (7) ◽

pp. 611-623

Author(s):

Ahmed A. Soliman ◽

Fawzy A. Attaby ◽

Othman I. Alajrawy ◽

Azza A.A. Abou-hussein ◽

Wolfgang Linert

Keyword(s):

Cell Line ◽

Cancer Cell ◽

Theoretical Calculations ◽

Thermal Analyses ◽

Cancer Cell Line ◽

Cellular Growth ◽

Planar Geometry ◽

Square Planar ◽

Vis Spectroscopy

Aim and Objective: Platinum (II) and platinum (IV) of pyrophosphate complexes have been prepared and characterized to discover their potential as antitumor drugs. This study was conducted to prepare and characterize new ternary platinum (II) complexes with formamidine and pyrophosphate as an antitumor candidate. Materials and Methods: The complexes have been characterized by mass, infrared, UV-Vis. spectroscopy, elemental analysis, magnetic susceptibility, thermal analyses, and theoretical calculations. They have been tested for their cytotoxicity, which was carried out using the fastcolorimetric assay for cellular growth and survival against MCF-7 (breast cancer cell line), HCT- 116 (colon carcinoma cell line), and HepG-2 (hepatocellular cancer cell line). Results: All complexes are diamagnetic, and the electronic spectral data displayed the bands due to square planar Pt(II) complexes. The optimized complexes structures (1-4) indicated a distorted square planar geometry where O-Pt-O and N-Pt-N bond angles were 82.04°-96.44°, respectively. Conclusion: The complexes showed noticeable cytotoxicity and are considered as promising antitumor candidates for further applications.

Download Full-text

LEAD-ZINC MINERALIZATION IN THE CRETACEOUS SEDIMENTS OF BENUE TROUGH OF NIGERIA

10.1130/abs/2018am-318791 ◽

2018 ◽

Author(s):

Nnaemeka Chidubem Onyeagba ◽

◽

Thomas Seifert

Keyword(s):

Benue Trough ◽

Lead Zinc

Download Full-text

Thermal analyses applied to ceramic nanopowders: from synthesis to sintering

Journal of Thermal Analysis and Calorimetry ◽

10.1007/s10973-012-2767-7 ◽

2012 ◽

Vol 112 (1) ◽

pp. 437-445 ◽

Cited By ~ 5

Author(s):

Laura Montanaro ◽

Paola Palmero ◽

Mariangela Lombardi ◽

Claude Esnouf ◽

Jérôme Chevalier ◽

...

Keyword(s):

Thermal Analyses

Download Full-text

Mortars with Recycled Aggregates from Building-Related Processes: A ‘Four-Step’ Methodological Proposal for a Review

Sustainability ◽

10.3390/su13052756 ◽

2021 ◽

Vol 13 (5) ◽

pp. 2756

Author(s):

Federica Vitale ◽

Maurizio Nicolella

Keyword(s):

Building Materials ◽

Thermal Analyses ◽

Construction Materials ◽

Physical And Mechanical Properties ◽

Research Trends ◽

Mix Design ◽

Recycled Aggregates ◽

Design Parameters ◽

Natural Aggregates ◽

By Products

Because the production of aggregates for mortar and concrete is no longer sustainable, many attempts have been made to replace natural aggregates (NA) with recycled aggregates (RA) sourced from factories, recycling centers, and human activities such as construction and demolition works (C&D). This article reviews papers concerning mortars with fine RA from C&D debris, and from the by-products of the manufacturing and recycling processes of building materials. A four-step methodology based on searching, screening, clustering, and summarizing was proposed. The clustering variables were the type of aggregate, mix design parameters, tested properties, patents, and availability on the market. The number and the type of the clustering variables of each paper were analysed and compared. The results showed that the mortars were mainly characterized through their physical and mechanical properties, whereas few durability and thermal analyses were carried out. Moreover, few fine RA were sourced from the production waste of construction materials. Finally, there were no patents or products available on the market. The outcomes presented in this paper underlined the research trends that are useful to improve the knowledge on the suitability of fine RA from building-related processes in mortars.

Download Full-text

Microstructure and Durability Performance of Mortars with Volcanic Powder from Calbuco Volcano (Chile) after 4 Hardening Years

Materials ◽

10.3390/ma14071751 ◽

2021 ◽

Vol 14 (7) ◽

pp. 1751

Author(s):

Rosa María Tremiño ◽

Teresa Real-Herraiz ◽

Viviana Letelier ◽

José Marcos Ortega

Keyword(s):

Water Absorption ◽

Thermal Analyses ◽

Length Change ◽

Cement Industry ◽

Chloride Diffusion ◽

Beneficial Effects ◽

State Diffusion ◽

Calbuco Volcano ◽

Reference Specimens ◽

The Impact

One of the most popular ways to lessen the impact of the cement industry on the environment consists of substituting clinker by additions. The service life required for real construction elements is generally long, so it would be interesting to obtain information about the effects of new additions after a hardening period of several years. Analyzed here are the effects of the incorporation of volcanic ashes, coming from Calbuco volcano’s last eruption (Chile), as clinker replacement, in the durability and pore structure of mortars, after approximately 4 hardening years (1500 days), in comparison with reference specimens without additions. The substitution percentages of clinker by volcanic powder studied were 10% and 20%. The microstructure was characterized with mercury intrusion porosimetry and impedance spectroscopy. In order to evaluate the pozzolanic activity of the volcanic powder after 1500 days, differential thermal analyses were performed. Water absorption after immersion, steady-state diffusion coefficient and length change were also studied. In accordance with the results obtained, the 10% and 20% substitution of clinker by volcanic powder from the Calbuco volcano showed beneficial effects in the mortars after 4 years, especially regarding the microstructure and chloride diffusion, without noticeable influence in their water absorption.

Download Full-text

Structure of the amorphous titania precursor phase of N-doped photocatalysts

RSC Advances ◽

10.1039/d0ra08886b ◽

2021 ◽

Vol 11 (15) ◽

pp. 8619-8627

Author(s):

I. E. Grey ◽

P. Bordet ◽

N. C. Wilson

Keyword(s):

Thermal Analyses ◽

Real Space ◽

Ammonia Solution ◽

Scattering Data ◽

X Ray ◽

X Ray Scattering ◽

Amorphous Titania ◽

Precursor Phase ◽

Titania Precursor ◽

Titanyl Sulphate

Amorphous titania samples prepared by ammonia solution neutralization of titanyl sulphate have been characterized by chemical and thermal analyses, and with reciprocal-space and real-space fitting of wide-angle synchrotron X-ray scattering data.

Download Full-text

Application of microwave radiation in the grafting of acidic sites on SBA-15 type material

Journal of Porous Materials ◽

10.1007/s10934-021-01077-1 ◽

2021 ◽

Author(s):

Maciej Trejda ◽

Magdalena Drobnik ◽

Ardian Nurwita

Keyword(s):

Microwave Radiation ◽

Thermal Analyses ◽

Conventional Heating ◽

Material Surface ◽

Test Reaction ◽

Study Materials ◽

Mesoporous Support ◽

Acidic Sites ◽

Post Synthesis ◽

Adsorption Desorption

AbstractMesoporous silica of SBA-15 type was modified for the first time with 3-(trihydroxysiyl)-1-propanesulfonic acid (TPS) by post-synthesis modification involving microwave or conventional heating in order to generate the Brønsted acidic centers on the material surface. The samples structure and composition were examined by low temperature N2 adsorption/desorption, XRD, HRTEM, elemental and thermal analyses. The surface properties were evaluated by esterification of acetic acid with n-hexanol used as the test reaction. A much higher efficiency of TPS species incorporation was reached with the application of microwave radiation for 1 h than conventional modification for 24 h. It was found that the structure of mesoporous support was preserved after modification using both methods applied in this study. Materials obtained with the use of microwave radiation showed a superior catalytic activity and high stability.

Download Full-text