Background: Calcium phosphate manufactured samples, prepared with hydroxyapatite, are used as either spacers or fillers in orthopedic surgery, but these implants have never been used under conditions of mechanical stress. Similar conditions also apply with cements. Many authors have postulated that cements are a useful substitute material when implanted in vivo. The aim of this research is to develop a low cristalline material similar to bone in porosity and cristallinity.
Methods: Commercial hydroxyapatite (HAp) and monetite (M) powders are mixed with water and compacted to produce cylindrical samples. The material is processed at a temperature of 37-120 degrees C in saturated steam to obtain samples that are osteoconductive. The samples are studied by X-ray powder diffraction (XRD), Vickers hardness test (HV), scanning electron microscopy (SEM), and porosity evaluation.
Results: The X-ray diffractions of powders from the samples show patterns typical of HAp and M powders. After thermal treatment, no new crystal phase is formed and no increase of the relative intensity of the peaks is obtained. Vicker hardness data do not show any relationship with treatment temperature. The total porosity decreases by 50-60% according to the specific thermal treatment. Scanning electron microscopy of the surfaces of the samples with either HAp 80%-M 20% (c) or Hap 50%-M 50% (f), show cohesion of the powder grains.
Conclusions: The dissolution-reprecipitation process is more intesive in manufactured samples (c) and (f), according to Vickers hardness data. The process occurs in a steam saturated environment between 37 degrees and 120 degrees C. (c) (f) manufactured samples show pore dimension distributions useful to cellular repopulation in living tissues.
Download full-text PDF |
Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC406414 | PMC |
| http://dx.doi.org/10.1186/1475-925X-3-8 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Benefits, challenges, and best practices of collaborative partnerships among health supply chain stakeholders in Rwanda: a cross-sectional study.
BMC Health Serv Res
January 2025
School of Medicine and Pharmacy, College of Medicine and Health Sciences, University of Rwanda, P.O. Box 3286, Kigali, Rwanda.
Background: Strong partnerships, community engagement, and multisectoral collaboration in the health supply chain are synergistic pillars towards achieving universal health coverage. In Rwanda, the health supply chain involves the collaboration of various stakeholders, including distributors, manufacturers, wholesalers, and customers. However, since the eruption and ending of COVID-19, there has not been any study to assess stakeholders' perspectives on the status of the benefits, challenges, and best practices of collaborative partnerships among health supply chain stakeholders in Rwanda.
View Article and Find Full Text PDFCucurbit[6]uril host-guest interaction assisted N-terminal epitope imprinted particles for cytochrome c recognition prepared by reversible addition-fragmentation chain transfer strategy.
Talanta
January 2025
Tianjin Key Laboratory of Biomedical Materials, Institute of Biomedical Engineering, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, 300192, People's Republic of China.
A novel strategy for cytochrome c selective recognition assisted with cucurbit[6]uril by host-guest interaction via N-terminal epitope imprinting and reversible addition-fragmentation chain transfer (RAFT) polymerization was developed. N-terminal nonapeptide of cytochrome c (GI-9) was used as the epitope template to achieve highly selective recognition of cytochrome c. As a common supramolecule in recent years, cucurbit[6]uril can encapsulate the butyrammonium group of lysine residue to capture the peptide and improve the corresponding spatial orientation by the host-guest interaction for GI-9 or cytochrome c recognition.
View Article and Find Full Text PDFMulti-Scale Pyramid Squeeze Attention Similarity Optimization Classification Neural Network for ERP Detection.
Neural Netw
January 2025
Key Laboratory of Smart Manufacturing in Energy Chemical Process, Ministry of Education, East China University of Science and Technology, Shanghai 200237, China; Center of Intelligent Computing, School of Mathematics, East China University of Science and Technology, Shanghai 200237, China. Electronic address:
Event-related potentials (ERPs) can reveal brain activity elicited by external stimuli. Innovative methods to decode ERPs could enhance the accuracy of brain-computer interface (BCI) technology and promote the understanding of cognitive processes. This paper proposes a novel Multi-Scale Pyramid Squeeze Attention Similarity Optimization Classification Neural Network (MS-PSA-SOC) for ERP Detection.
View Article and Find Full Text PDFMolecular H as the Reducing Agent in Low-Temperature Oxide Reduction Using Calcium Hydride.
J Am Chem Soc
January 2025
Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States.
Low-temperature synthesis is crucial for advancing sustainable manufacturing and accessing novel metastable phases. Metal hydrides have shown great potential in facilitating the reduction of oxides at low temperatures, yet the underlying mechanism─whether driven by H, H, or atomic H─remains unclear. In this study, we employ electrical transport measurements and first-principles calculations to investigate the CaH-driven reduction kinetics in epitaxial α-FeO thin films.
View Article and Find Full Text PDFIon exchange chromatography of biotherapeutics: Fundamental principles and advanced approaches.
J Chromatogr A
January 2025
School of Pharmaceutical Sciences, University of Geneva, CMU - Rue Michel Servet 1, 1211 Geneva 4, Switzerland; Institute of Pharmaceutical Sciences of Western Switzerland, University of Geneva, CMU - Rue Michel Servet 1, 1211 Geneva 4, Switzerland. Electronic address:
Ion exchange chromatography (IEX) is an important analytical technique for the characterization of biotechnology-derived products, such as monoclonal antibodies (mAbs) and more recently, cell and gene therapy products such as messenger ribonucleic acid (mRNA) and adeno-associated viruses (AAVs). This review paper first outlines the basic principles and separation mechanisms of IEX for charge variant separation of biotherapeutics, and examines the different elution modes based on salt or pH gradients. It then highlights several recent trends when applying IEX for the characterization of biotechnology-derived products, including: i) the effective use of pH gradients, ii) the improvement of selectivity by using organic solvents in the mobile phase, multi-step gradients, or by combining ion pairing and ion exchange, and iii) the increase in analytical throughput using ultra-short columns or automated screening of conditions.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!