title: A review on the use of Hydroxyapatite-carbonaceous structure composites in bone replacement materials for strengthening purposes

authors: Siddiqui, Humair Ahmed

subjects: Science & Technology

abstract: Biomedical materials constitute a vast scientific research field, which is devoted to producing medical devices which aid in enhancing human life. In this field, there is an enormous demand for long-lasting implants and bone substitutes that avoid rejection issues whilst providing favourable bioactivity, osteoconductivity and robust mechanical properties. Hydroxyapatite (HAp)-based biomaterials possess a close chemical resemblance to the mineral phase of bone, which give rise to their excellent biocompatibility, so allowing for them to serve the purpose of a bone-substituting and osteoconductive scaffold. The biodegradability of HAp is low (Ksp ≈ 6.62 × 10⁻¹²⁶) as compared to other calcium phosphates materials, however they are known for their ability to develop bone-like apatite coatings on their surface for enhanced bone bonding. Despite its favourable bone regeneration properties, restrictions on the use of pure HAp ceramics in high load-bearing applications exist due to its inherently low mechanical properties (including low strength and fracture toughness, and poor wear resistance). Recent innovations in the field of bio-composites and nanoscience have reignited the investigation of utilising different carbonaceous materials for enhancing the mechanical properties of composites, including HAp-based bio-composites. Researchers have preferred carbonaceous materials with hydroxyapatite due to their inherent biocompatibility and good structural properties. It has been demonstrated that different structures of carbonaceous material can be used to improve the fracture toughness of HAp, as they can easily serve the purpose of being a second phase reinforcement, with the resulting composite still being a biocompatible material. Nanostructured carbonaceous structures, especially those in the form of fibres and sheets, were found to be very effective in increasing the fracture toughness values of HAp. Minor addition of CNTs (3 wt.%) has resulted in a more than 200% increase in fracture toughness of hydroxyapatite-nanorods/CNTs made using spark plasma sintering. This paper presents a current review of the research field of using different carbonaceous materials composited with hydroxyapatite with the intent being to produce high performance biomedically targeted materials.

text: A review on the use of Hydroxyapatite-carbonaceous structure composites in bone replacement materials for strengthening purposes Biomedical materials constitute a vast scientific research field, which is devoted to producing medical devices which aid in enhancing human life. In this field, there is an enormous demand for long-lasting implants and bone substitutes that avoid rejection issues whilst providing favourable bioactivity, osteoconductivity and robust mechanical properties. Hydroxyapatite (HAp)-based biomaterials possess a close chemical resemblance to the mineral phase of bone, which give rise to their excellent biocompatibility, so allowing for them to serve the purpose of a bone-substituting and osteoconductive scaffold. The biodegradability of HAp is low (Ksp ≈ 6.62 × 10⁻¹²⁶) as compared to other calcium phosphates materials, however they are known for their ability to develop bone-like apatite coatings on their surface for enhanced bone bonding. Despite its favourable bone regeneration properties, restrictions on the use of pure HAp ceramics in high load-bearing applications exist due to its inherently low mechanical properties (including low strength and fracture toughness, and poor wear resistance). Recent innovations in the field of bio-composites and nanoscience have reignited the investigation of utilising different carbonaceous materials for enhancing the mechanical properties of composites, including HAp-based bio-composites. Researchers have preferred carbonaceous materials with hydroxyapatite due to their inherent biocompatibility and good structural properties. It has been demonstrated that different structures of carbonaceous material can be used to improve the fracture toughness of HAp, as they can easily serve the purpose of being a second phase reinforcement, with the resulting composite still being a biocompatible material. Nanostructured carbonaceous structures, especially those in the form of fibres and sheets, were found to be very effective in increasing the fracture toughness values of HAp. Minor addition of CNTs (3 wt.%) has resulted in a more than 200% increase in fracture toughness of hydroxyapatite-nanorods/CNTs made using spark plasma sintering. This paper presents a current review of the research field of using different carbonaceous materials composited with hydroxyapatite with the intent being to produce high performance biomedically targeted materials.

year: 2018

title: Exploring the landscapes of external supervision

authors: Flintoff, Vivianne

subjects: counselling supervision

abstract: External supervision offers health and social service practitioners opportunities for exploring their work, professional development, and associated relationships. Within a context outside of the workplace, the supervision relationship allegedly supports practice within the workplace. There is a range of understanding within the sectors about the relationship between supervisor and practitioner. This paper explores the potential of closer relationships between agency and supervisor and the subsequent possibilities for greater accountability of the supervision work. Reflecting on our own practice as supervisors both within agencies and external to agencies, this paper invites readers (supervisors and practitioners) to draw on their own supervision experiences. The intention is to critique, challenge, and support critical reflection upon current and potential supervision arrangements for practitioners who participate in supervision that is external to their agencies.

text: Exploring the landscapes of external supervision External supervision offers health and social service practitioners opportunities for exploring their work, professional development, and associated relationships. Within a context outside of the workplace, the supervision relationship allegedly supports practice within the workplace. There is a range of understanding within the sectors about the relationship between supervisor and practitioner. This paper explores the potential of closer relationships between agency and supervisor and the subsequent possibilities for greater accountability of the supervision work. Reflecting on our own practice as supervisors both within agencies and external to agencies, this paper invites readers (supervisors and practitioners) to draw on their own supervision experiences. The intention is to critique, challenge, and support critical reflection upon current and potential supervision arrangements for practitioners who participate in supervision that is external to their agencies.

year: 2010

title: Bicultural perspectives on Māori legal research

authors: Mackinnon, Jacquelin

subjects: Māori

abstract: Increasingly, legal research projects undertaken at law school or in practice will involve Māori custom law and/or tikanga Māori.' The role of both Māori custom law and tikanga Māori is most evident in the work of the Māori Land Court in the interpretation and application of legislation relating to Māori land. Increasingly, general statutes incorporate Māori principles and values, such as those to be found in the Resource Management Act 1991, or make explicit reference to the principles of the Treaty of Waitangi. The statutory interpretation function of the Courts in relation to these, and less obvious examples, requires knowledge of tikanga Māori and/or Māori custom law. For any analysis of the work of the Courts or of the legislature, knowledge of tikanga Māori and/or custom law is required. Both Māori custom law and tikanga Māori are preserved by and accessed through the oral tradition. In addition to its role in the Courts and in relation to legislation, the most significant role played by the oral tradition is in the work of the Waitangi Tribunal. The oral tradition also plays an increasingly important part in other areas requiring research. What follows is an introduction to the oral tradition and its role in the legal system of Aotearoa/New Zealand. An understanding of the oral tradition is essential to the construction of a research path that is both ethical and effective.

text: Bicultural perspectives on Māori legal research Increasingly, legal research projects undertaken at law school or in practice will involve Māori custom law and/or tikanga Māori.' The role of both Māori custom law and tikanga Māori is most evident in the work of the Māori Land Court in the interpretation and application of legislation relating to Māori land. Increasingly, general statutes incorporate Māori principles and values, such as those to be found in the Resource Management Act 1991, or make explicit reference to the principles of the Treaty of Waitangi. The statutory interpretation function of the Courts in relation to these, and less obvious examples, requires knowledge of tikanga Māori and/or Māori custom law. For any analysis of the work of the Courts or of the legislature, knowledge of tikanga Māori and/or custom law is required. Both Māori custom law and tikanga Māori are preserved by and accessed through the oral tradition. In addition to its role in the Courts and in relation to legislation, the most significant role played by the oral tradition is in the work of the Waitangi Tribunal. The oral tradition also plays an increasingly important part in other areas requiring research. What follows is an introduction to the oral tradition and its role in the legal system of Aotearoa/New Zealand. An understanding of the oral tradition is essential to the construction of a research path that is both ethical and effective.

year: 2007