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: An experimental investigation of the self-management therapies: coverant control and covert sensitization

authors: Saunders, Steven Arthur

abstract: The relative efficacies of the SM techniques of Coverant Control (CC) and Covert Sensitization (CS), when applied singly and in combination, are investigated. Rate of cigarette smoking is the dependent variable. 

From an initial sample of 61 volunteers, smokers wishing to quit, 55 subjects (S’s) maintained contact and comprised the study group. Eleven S’s formed a non-treated control condition while the remaining 44 were distributed equally across 4 experimental conditions. These groups included a Placebo condition, CC, CS and CS + CC combined. 

It was hypothesised that CS and CC would prove more effective than a Placebo condition which involved contact only. It was further hypothesised that CS+ CC, administered as a combined package, would prove more effective in maintaining in-treatment gains at follow-up than when either of these treatments was administered singly.

The statistical analyses indicated no significant differences between the experimental groups receiving regular contact. All groups, except the non-treated controls, did reduce cigarette consumption while the programme lasted. However, on follow-up there was an almost uniform return toward baseline rates, with the SM treatment S’s not differing from those in the Placebo group.

These data are discussed in terms of possible implications for the development of SM techniques that are clinically useful with cigarette smokers.

text: An experimental investigation of the self-management therapies: coverant control and covert sensitization The relative efficacies of the SM techniques of Coverant Control (CC) and Covert Sensitization (CS), when applied singly and in combination, are investigated. Rate of cigarette smoking is the dependent variable. 

From an initial sample of 61 volunteers, smokers wishing to quit, 55 subjects (S’s) maintained contact and comprised the study group. Eleven S’s formed a non-treated control condition while the remaining 44 were distributed equally across 4 experimental conditions. These groups included a Placebo condition, CC, CS and CS + CC combined. 

It was hypothesised that CS and CC would prove more effective than a Placebo condition which involved contact only. It was further hypothesised that CS+ CC, administered as a combined package, would prove more effective in maintaining in-treatment gains at follow-up than when either of these treatments was administered singly.

The statistical analyses indicated no significant differences between the experimental groups receiving regular contact. All groups, except the non-treated controls, did reduce cigarette consumption while the programme lasted. However, on follow-up there was an almost uniform return toward baseline rates, with the SM treatment S’s not differing from those in the Placebo group.

These data are discussed in terms of possible implications for the development of SM techniques that are clinically useful with cigarette smokers.

year: 1973

title: "Kia Mauri Tau!" Narratives of recovery from disabling mental health problems

authors: Lapsley, Hilary

subjects: Maori

abstract: A bicultural research team at the University of Waikato successfully applied for funding from the Health Research Council to do a qualitative research project in the area of ‘pathways to wellness’. The Mental Health Narratives Project set out to gather forty narratives of mental ill health, recovery and life after recovery by interviewing Maori and non-Maori women and men who once had a disabling mental health problem. We aimed to describe journeys to mental health, identify key themes in accounts of the recovery process and describe the impact of the experience of mental ill health on life after recovery.

text: "Kia Mauri Tau!" Narratives of recovery from disabling mental health problems A bicultural research team at the University of Waikato successfully applied for funding from the Health Research Council to do a qualitative research project in the area of ‘pathways to wellness’. The Mental Health Narratives Project set out to gather forty narratives of mental ill health, recovery and life after recovery by interviewing Maori and non-Maori women and men who once had a disabling mental health problem. We aimed to describe journeys to mental health, identify key themes in accounts of the recovery process and describe the impact of the experience of mental ill health on life after recovery.

year: 2002