I feel it in my bones! An investigation into the mechanical and structural changes to bone as we age

3MT presented at the 2017 Defence and Security Doctoral Symposium.Bone biomechanics is concerned with the study of the ailments and performance of our musculoskeletal system. Our knowledge of this field has been propelled forward by those in the automotive industry, who specialise in applied biomechanics and engineering. Their interest in this subject matter stems from the continual need to improve vehicle safety, but our skeletons also provide anthropological records of our lives, and can even act as a record of a criminal act. The aim of this research is to conduct a detailed assessment to examine the changes that occur to the structural and mechanical properties of the rib and clavicle bones, as we age. This multimethod approach will combine a non-invasive technique, micro-computed tomography (µ-CT), with multiple invasive methods including nanoindentation, dynamic mechanical analysis (DMA) and DSC-TGA. The proposed outcome of this research will be to use the resulting data to create a more comprehensive overview of the microarchitecture and mechanical behaviour of the rib and clavicle bones, which can then be used collaboratively with various disciplines. Understanding how these bones deteriorate with age will be particularly helpful for mitigating skeletal brittleness in some vulnerable groups like the elderly, by informing orthopaedic surgeons on the structure and condition of bone, which in turn could assist with the management of fractures through treatment and rehabilitation. Forensic anthropology, in parallel, will draw information to establish mechanisms of trauma, providing critical information for forensic investigations, as well as archaeological case studies that bear injuries, and in grasping the historical context for archaeological studies of past populations.EPSR

Age-related trends in the trabecular micro-architecture of the medial clavicle: is it of use in forensic science?

The mechanical and structural properties of bone are known to change significantly with age. Within forensic and archaeological investigations, the medial end of the clavicle is typically used for estimating the age-at-death of an unknown individual. Although, this region of the skeleton is of interest to forensic and clinical domains, alterations beyond the macro-scale have not been fully explored. For this study, non-destructive micro-computed tomography (µ-CT) was employed to characterize structural alterations to the cancellous bone of the medial clavicle. Fresh human cadaveric specimens (12-59 years) obtained at autopsy were utilized for this study, and were scanned with a voxel size of ∼83µm. Morphometric properties were quantified and indicated that the bone volume, connectivity density, mineral density, and number of trabeculae decreased with age, while the spacing between the trabeculae increased with age. In contrast to other sub-regions of the skeleton, trabecular thickness, and degree of anisotropy did not correlate with age. Collectively, this could suggest that the network is becoming increasingly perforated with age rather than exhibiting trabecular thinning. These results are used in the context of deriving a potential protocol for forensic investigations by using this particular and largely unexplored region of the skeleton, and provide inspiration for future experiments concerning micro-architectural and small scale changes in other regions of the human skeleton

Elective cancer surgery in COVID-19-free surgical pathways during the SARS-CoV-2 pandemic: An international, multicenter, comparative cohort study

PURPOSE As cancer surgery restarts after the first COVID-19 wave, health care providers urgently require data to determine where elective surgery is best performed. This study aimed to determine whether COVID-19–free surgical pathways were associated with lower postoperative pulmonary complication rates compared with hospitals with no defined pathway. PATIENTS AND METHODS This international, multicenter cohort study included patients who underwent elective surgery for 10 solid cancer types without preoperative suspicion of SARS-CoV-2. Participating hospitals included patients from local emergence of SARS-CoV-2 until April 19, 2020. At the time of surgery, hospitals were defined as having a COVID-19–free surgical pathway (complete segregation of the operating theater, critical care, and inpatient ward areas) or no defined pathway (incomplete or no segregation, areas shared with patients with COVID-19). The primary outcome was 30-day postoperative pulmonary complications (pneumonia, acute respiratory distress syndrome, unexpected ventilation). RESULTS Of 9,171 patients from 447 hospitals in 55 countries, 2,481 were operated on in COVID-19–free surgical pathways. Patients who underwent surgery within COVID-19–free surgical pathways were younger with fewer comorbidities than those in hospitals with no defined pathway but with similar proportions of major surgery. After adjustment, pulmonary complication rates were lower with COVID-19–free surgical pathways (2.2% v 4.9%; adjusted odds ratio [aOR], 0.62; 95% CI, 0.44 to 0.86). This was consistent in sensitivity analyses for low-risk patients (American Society of Anesthesiologists grade 1/2), propensity score–matched models, and patients with negative SARS-CoV-2 preoperative tests. The postoperative SARS-CoV-2 infection rate was also lower in COVID-19–free surgical pathways (2.1% v 3.6%; aOR, 0.53; 95% CI, 0.36 to 0.76). CONCLUSION Within available resources, dedicated COVID-19–free surgical pathways should be established to provide safe elective cancer surgery during current and before future SARS-CoV-2 outbreaks

Elective Cancer Surgery in COVID-19-Free Surgical Pathways During the SARS-CoV-2 Pandemic: An International, Multicenter, Comparative Cohort Study.

PURPOSE: As cancer surgery restarts after the first COVID-19 wave, health care providers urgently require data to determine where elective surgery is best performed. This study aimed to determine whether COVID-19-free surgical pathways were associated with lower postoperative pulmonary complication rates compared with hospitals with no defined pathway. PATIENTS AND METHODS: This international, multicenter cohort study included patients who underwent elective surgery for 10 solid cancer types without preoperative suspicion of SARS-CoV-2. Participating hospitals included patients from local emergence of SARS-CoV-2 until April 19, 2020. At the time of surgery, hospitals were defined as having a COVID-19-free surgical pathway (complete segregation of the operating theater, critical care, and inpatient ward areas) or no defined pathway (incomplete or no segregation, areas shared with patients with COVID-19). The primary outcome was 30-day postoperative pulmonary complications (pneumonia, acute respiratory distress syndrome, unexpected ventilation). RESULTS: Of 9,171 patients from 447 hospitals in 55 countries, 2,481 were operated on in COVID-19-free surgical pathways. Patients who underwent surgery within COVID-19-free surgical pathways were younger with fewer comorbidities than those in hospitals with no defined pathway but with similar proportions of major surgery. After adjustment, pulmonary complication rates were lower with COVID-19-free surgical pathways (2.2% v 4.9%; adjusted odds ratio [aOR], 0.62; 95% CI, 0.44 to 0.86). This was consistent in sensitivity analyses for low-risk patients (American Society of Anesthesiologists grade 1/2), propensity score-matched models, and patients with negative SARS-CoV-2 preoperative tests. The postoperative SARS-CoV-2 infection rate was also lower in COVID-19-free surgical pathways (2.1% v 3.6%; aOR, 0.53; 95% CI, 0.36 to 0.76). CONCLUSION: Within available resources, dedicated COVID-19-free surgical pathways should be established to provide safe elective cancer surgery during current and before future SARS-CoV-2 outbreaks

Changes to the micro-architecture and material properties of the human clavicle and rib in ontogeny

The detrimental effects of ageing on the human skeleton are universally resonant. With increase in age, an increased fragility at the macroscopic scale is observed in bone, which is indicative of changes that occur at different levels within the heterogeneous and complex, hierarchical arrangement of this biological composite. In spite of that, a comprehensive understanding of ageing characteristics in the medial clavicle is largely missing from the literature. The seminal research currently available concerns developmental markers such as morphological alterations to shape and structure, which are capped at the point of skeletal maturity. Estimating age-at-death continues to be one of the most challenging responsibilities for forensic anthropologists when compiling a biological profile for unidentified skeletonised human remains (most especially following the maturation of the skeleton). The medial clavicle and sternal rib ends are fundamental to age estimation; the former is the last bone to fuse in the human skeleton making the development ideal for estimating age when the remainder of the skeleton has completed epiphyseal fusion, and the latter are easily accessible during routine autopsy. Current methods which utilise these skeletal sub-regions are primarily qualitative and rely on the expert interpretation of subjective traits which relate to broad and descriptive phase categories. There is a need to go beyond using morphological biomarkers currently employed in forensic anthropology. The introduction of new, quantitative techniques is therefore fundamental to addressing the following unanswered question: what significant, ontogenetic changes occur beyond the macro-scale which can be utilised for generating multivariate age prediction models for the clavicle and rib? In order to address this question, the primary research aim for this research was to characterise statistically significant (p0.7 to effectively predict age-at-death. This novel approach addresses disciplinary norms through the application of micro-computed tomography (µ-CT), nanoindentation and the combined diagnostic power of two thermo-analytical techniques (DSC-TGA) to elucidate agerelated changes in a sample of 161 cadaveric specimens from 58 donors at a scale beyond what has thus far been presented in the literature. Accordingly, a series of associated hypotheses were devised concerning the individual constituent parts, which altogether contribute to the physical manifestiations of age and form the complex arrangment of bone, using each of these techniques. The effect of the size of the sample has also been considered. The age range of the sample in question (12-59 years) focuses on a division of the age spectrum which has received less attention in previous studies, particularly in comparison to study groups which have primarily comprised of elderly individuals. Firstly, a non-destructive assessment of the morphometric characteristics of the trabecular bone located in the medial end of the clavicle was implemented using micro-computed tomography (µ-CT) to test for statistically signficant (p0.7 which is indicative of a strong model. iv Additionally, the value of adopting a multi-method system was illustrated using Principal Component Analysis (PCA) which revealed the extent to which principal components (namely HVIT, EIT, percentage loss of organic weight [Or%] and final percentage weight of mineral phase [Ash%]) were contributing to clustering patterns associated with age. These findings explore the research hypothesis which concerns the identification of changes to clavicle and rib physiology and mechanical behaviour in ontogeny; details that will hold significant value in medico-legal cases for age-atdeath estimation. This research also addresses set objectives concerned with the development of easily reproducible and accurate methods of age-at-death estimation using the medial clavicle and sternal end of the sixth rib without specialist anthropological expertise. The results presented also contribute to basic knowledge of mechano-biology for micro- and nano-structures that influence fracture risk at the organ level, which is of interest to clinicians in orthopaedic biomechanics and is also vital to other sectors. For example, the automotive industry can use such data to establish whether age-related changes to the structure and material composition of these bones lessens the failure threshold and mechanical behaviour of the chest in vehicle collisions. This information in turn could also contribute to the improvememt of automotive safety designs

Predicted growth in plastic waste exceeds efforts to mitigate plastic pollution

Plastic pollution is a planetary threat, affecting nearly every marine and freshwater ecosystem globally. In response, multilevel mitigation strategies are being adopted but with a lack of quantitative assessment of how such strategies reduce plastic emissions. We assessed the impact of three broad management strategies, plastic waste reduction, waste management, and environmental recovery, at different levels of effort to estimate plastic emissions to 2030 for 173 countries. We estimate that 19 to 23 million metric tons, or 11%, of plastic waste generated globally in 2016 entered aquatic ecosystems. Considering the ambitious commitments currently set by governments, annual emissions may reach up to 53 million metric tons per year by 2030. To reduce emissions to a level well below this prediction, extraordinary efforts to transform the global plastics economy are needed