Synthesis of hydroxyapatite (HAp) and microwave assisted TiO2-HAp composite coating on Commercially pure (CP)-Titanium for biomedical applications

Hydroxyapatite (HAp) is an important bioceramic material widely used for many biomedical applications owing to its similarity to the inorganic composition of bone. Hydroxyapatite was synthesized by using wet precipitation method using calcium nitrate and diammonium hydrogen phosphate as a precursor. To maintain a constant pH, ammonium hydroxide solution was used. After synthesis, HAp samples were calcined at 850 °C and 1200 °C, for 2 hours, and allowed to cool at room temperature. The synthesized HAp and calcined HAp samples were characterized by X-ray diffraction (XRD), attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), scanning electron microscope (SEM), and transmission electron microscopy (TEM). Zeta potential test was performed and its values were found to be between -14.7 mV and -15.7 mV. The result inferred that hydroxyapatite particles would get precipitated in a short span of time and, not stable in colloidal solution. Dynamic light scattering (DLS) was also used to determine particle size distribution. The z-average diameter of particles was found to range from 400 nm to 457 nm. Transmission electron microscopy (TEM) result confirmed that calcined HAp (1200°C) has the largest particle size and synthesized HAp has the smallest particle size. After synthesis of HAp, microwave (MW) has been used as a substitutive method for HAp-based composite coatings on commercially pure (CP) titanium substrate. This is performed to enhance the bioactivity which is an important property for biomedical implants. The coating was made by microwave processing of CP-Ti packed in HAp at moderately higher microwave power. The composition of coating demonstrates TiO2 as a major phase (which was formed due to oxidation) along with HAp as a minor phase. Synthesized HAp and calcined (850 °C) HAp coating on CP-Ti were performed and characterized. The XRD and SEM results confirmed the presence of TiO2 and HAp on the CP-Ti specimens. The coated samples showed improved mechanical and biological performances. Microhardness of CP-Ti specimens increased after microwave processing, as the microhardness values of uncoated, synthesized HAp coated, and calcined (at 850 °C) HAp coated CP-Ti samples are 172.64 HV, 192.1 HV, and 192.45 HV respectively. Hence the studied showed that TiO2-HAp coated CP-Ti specimens has significant potential in a biomedical application with improved bioactive properties

Rigorous results on the threshold network model

We analyze the threshold network model in which a pair of vertices with random weights are connected by an edge when the summation of the weights exceeds a threshold. We prove some convergence theorems and central limit theorems on the vertex degree, degree correlation, and the number of prescribed subgraphs. We also generalize some results in the spatially extended cases.Comment: 21 pages, Journal of Physics A, in pres

Mapping the Contours: Utopic and Dystopic Perspectives on the Use of AI in Higher Education

This paper explores the impact of artificial intelligence (AI) on education, with a focus on assessment and academic integrity in higher education. We conducted a thematic analysis of literature on AI and academic integrity, framed by possible utopic and dystopic scenarios. We found that AI can be used to generate text, summarize work, create outlines, and provide information and resources on a particular topic, saving time and money. We argue that effective institutional policies should be established around the use of AI technologies, such as ChatGPT, to better serve the fields of education and academic research. The paper also discusses the implications of AI for university students, including the potential for personalized learning, quick feedback on student work, and improved accessibility for students with disabilities. However, the use of AI in education raises concerns about academic integrity and the potential for cheating. We caution that ethical considerations under existing academic integrity frameworks must be considered when implementing AI in education. The article concludes by calling for further research on the impact of AI on education and the development of guidelines and policies to ensure that AI is used in a responsible and ethical manner

The qudit Pauli group: non-commuting pairs, non-commuting sets, and structure theorems

Qudits with local dimension $d>2$ can have unique structure and uses that qubits ($d=2$) cannot. Qudit Pauli operators provide a very useful basis of the space of qudit states and operators. We study the structure of the qudit Pauli group for any, including composite, $d$ in several ways. For any specified set of commutation relations, we construct a set of qudit Paulis satisfying those relations. We also study the maximum size of sets of Paulis that mutually non-commute and sets that non-commute in pairs. Finally, we give methods to find near minimal generating sets of Pauli subgroups, calculate the sizes of Pauli subgroups, and find bases of logical operators for qudit stabilizer codes. Useful tools in this study are normal forms from linear algebra over commutative rings, including the Smith normal form, alternating Smith normal form, and Howell normal form of matrices.Comment: 35 pages, 1 figur