Tailoring mechanical properties in 3D printed multimaterial architected structures

In recent years, significant advancements have been made in developing architected materials, known for their benefits like being lightweight, customizable mechanical performance, and excellent energy absorption. The capabilities of 3D printing technology have facilitated the emergence of a diverse range of architected structures, featuring various unit cell types and geometries for different applications. This study explores the unique opportunity offered by multimaterial 3D printing in fine-tuning the mechanical performance of architected structures. The exploration of the programmability of these structures involves a systematic assessment of various material candidates. After careful evaluation, the selection process led to the choice of PLA and PCL biopolymers for the multimaterial structure. Experimental results emphasize the key role of design configurations in influencing mechanical characteristics, particularly in enhancing the energy absorption capacity of architected structures. By skillfully manipulating the local structure and composition through the synergistic combination of soft and hard materials, the study demonstrates the ability to achieve a diverse range of mechanical responses. The discovered insights present a promising approach that holds applicability in the design and development of multifunctional devices. This is especially significant in the biomedical field, where there is a growing demand for versatile devices.

Legal issues and underexplored data protection in medical 3D printing: A scoping review

Introduction: 3D printing has quickly found many applications in medicine. However, as with any new technology the regulatory landscape is struggling to stay abreast. Unclear legislation or lack of legislation has been suggested as being one hindrance for wide-scale adoption. Methods: A scoping review was performed in PubMed, Web of Science, SCOPUS and Westlaw International to identify articles dealing with legal issues in medical 3D printing. Results: Thirty-four articles fulfilling inclusion criteria were identified in medical/technical databases and fifteen in the legal database. The majority of articles dealt with the USA, while the EU was also prominently represented. Some common unresolved legal issues were identified, among them terminological confusion between custom-made and patient-matched devices, lack of specific legislation for patient-matched products, and the undefined legal role of CAD files both from a liability and from an intellectual property standpoint. Data protection was mentioned only in two papers and seems an underexplored topic. Conclusion: In this scoping review, several relevant articles and several common unresolved legal issues were identified including a need for terminological uniformity in medical 3D printing. The results of this work are planned to inform our own deeper legal analysis of these issues in the future.

The effect of lifestyle and risk factor modification on occlusive peripheral arterial disease outcomes: standard healthcare vs structured programme: a pilot randomised controlled study

Funding Acknowledgements

Type of funding sources: None.

Background

Atherosclerotic risk factor modification plays an important role in reducing adverse outcomes in patients with atherosclerotic disease1. Despite the high prevalence of peripheral arterial disease (PAD) and strong association with cardiovascular morbidity and mortality, patients with PAD are less likely to receive structured treatment for their atherosclerotic risk factors than patients with coronary artery disease2,3.

Purpose

We aim to evaluate the effectiveness of a lifestyle and risk factor modification intervention programme in achieving treatment goals for PAD risk factors.

Methods

This is a pilot randomised controlled study comparing a risk factor modification intervention programme to standard healthcare, for the reduction of modified risk factors in PAD patients. Patients randomised to the intervention arm underwent a 12-week supervised programme adjusting their risk factors. Primary outcome was patients reaching target risk factor improvement.

Results

Seventy-five patients were randomised. 36 were allocated to Standard Healthcare. 39 completed a 12-week Structured Programme. There was no significant difference between groups in baseline demographics, incidence and severity of risk factors, mobility and quality of life.

At 12-weeks the intervention group showed a significant improvement in target body weight (6.7±9.57 p=0.002), waist circumference (7.4±9.5 p=0.001), HbA1c (4.12±7.22 p=0.009), total cholesterol (0.63±0.99 p=0.004), low-density lipoprotein (0.59±1.040 p=0.00), triglycerides (0.24±0.38 p=0.005), Mediterranean diet score (2.48±1.35 p=0.0001), Absolute Walking Distance (8.2±7.8 p=0.0001), Claudication Distance (9.2±7.4 p=0.0001). There was no significant difference in the change of any of the other risk factors.

Conclusion

Risk factor modification intervention programme can significantly aid PAD patients reach their target risk factor improvement goals.

Outcomes from a digital cardiovascular prevention and rehabilitation programme delivered in Ireland during COVID 19

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Government of Ireland's Sláintecare Integration Fund Health Research Board, Ireland

Background & Aim

COVID 19 has accelerated the uptake and acceptance of digital health tools for the prevention and management of Cardiovascular Disease. With health systems being urged to learn from the pandemic and to reassess how they will deliver services in future, robust audit and evaluation of digital interventions are required to inform best practice.

This study aims to evaluate the clinical outcomes of a digital CVD prevention and rehabilitation programme which was established during COVID 19 to provide cardiac patients with efficient and timely access to a home-based, structured, comprehensive programme of care.

Methods

Developed and delivered by an interdisciplinary team (Nurse Prescriber, Physiotherapist, Dietitian, Cardiologist), the core components of this 12 week programme included, behavioural change support, lifestyle modification, medical risk factor management and electronic prescribing of cardio-protective medication. To support self-management, patients were provided with a Fitbit, blood pressure monitor and a workbook to support goal setting and overall tracking of progress. Patients were given access to a bespoke web-based platform and invited to attend weekly (2hr) group-based sessions, which included an exercise component and an interactive educational workshop.

Results

Over a 4 month period, 105 patients were referred with an uptake rate of 73% (n=77). Of these, 97% (n=75) enrolled in the programme, with an 85% (n=64) completion rate. Significant improvements in CVD risk factors were observed between initial and end of programme assessment. The proportion of patients meeting guideline-recommended physical activity targets increased from 14 to 82% (p<0.001), mean BMI (kg/m2) reduced from 28.7 to 27.7 (p<0.001), mean Mediterranean diet score improved from 5.2 to 7.3 (p<0.001), and anxiety and depression levels ≥8 (Hospital Anxiety and Depression score) both reduced by more than 50% (p<0.001). The proportions achieving the recommended blood pressure (<130/80 mmHg) and LDL cholesterol targets (<1.4 mmol/L) increased from 24 to 68% (p<0.001) and 14 to 41% (p<0.001), respectively.

Conclusion

Outcomes from this programme demonstrate that digital CVD prevention and rehabilitation programmes can achieve the recommended lifestyle, medical and therapeutic targets associated with reduced CVD events and improved health outcomes. This programme represents a scalable, accessible and effective option to deliver vital CVD preventive care in the patient’s home.

Canine mammary gland disease in New Zealand: a review of samples from 797 dogs

AIMS

To evaluate the proportions of canine mammary gland lesions submitted to a New Zealand diagnostic laboratory, that were neoplastic vs. non-neoplastic lesions and, among neoplasms, malignant vs. benign, and to determine whether age, reproductive status or breed of dog, or size of the mammary mass were associated with the histological diagnosis.

METHODS

Canine mammary gland biopsies submitted between the start of 2012 and the end of 2016 were selected from the surgical biopsy database of IDEXX Laboratories, NZ. For each case, details on age, breed, and reproductive status of the patient were registered as reported by the submitting veterinarians, along with the size of the lesion and the histological diagnosis reported by the pathologists. χ² tests and independent sample t-tests were performed to evaluate associations.

RESULTS

Samples (n=895) were submitted from 797 dogs, of which 673 had mammary neoplasms while 124 had non-neoplastic lesions. Neoplasms composed of a single nodule were found in 591/673 (87.8%) dogs while 82/673 (12.2%) dogs had multiple nodules. Of the total 771 neoplasms, 432 (56.0%) were histologically malignant, while 339 (44.0%) were benign. Among malignancies, the most common histological sub-types were simple carcinoma (160/771; 20.8%), complex carcinoma (54/771; 7%), and ductal carcinoma (32/771; 4.2%), while benign mixed mammary tumour (128/771, 16.6%) and complex adenoma (105/771; 13.6%) were the most frequently reported benign mammary neoplasms. Age (p=0.09), reproductive status (p=0.79) and size of the mass (p=0.21) were not significantly different between neoplastic and non-neoplastic lesions. However, neoplastic mammary gland lesions were more frequent in purebred dogs (612/671; 91.2%) than crossbred dogs (61/126; 48.4%; p<0.001). Age (p=0.15) reproductive status (p=0.36) or breed (p=0.45) were not significantly different between malignant and benign neoplasms. There was a significant strong association between size and histological benign or malignant status of a neoplasm (φ=0.65, p<0.001).

CONCLUSIONS

Most canine mammary gland samples submitted for examination were neoplastic with slightly more malignant than benign lesions. Masses submitted from purebred dogs were more likely to be neoplastic while large neoplasms were more likely to be malignant.

CLINICAL RELEVANCE

The present findings provide a first description of distribution of mammary gland lesions in a relatively large number of dogs in New Zealand, representing a preliminary investigation of canine mammary gland diseases in this country.

What am I doing here? Enablers and barriers to community-based cardiac rehabilitation attendance: a qualitative study utilising a behavioural science approach

Funding Acknowledgements

Type of funding sources: Public Institution(s). Main funding source(s): Community Engaged Scholars Programme (CES-P), PPI Ignite, National University of Ireland, Galway

Background

Despite the well-established benefits of cardiovascular prevention and rehabilitation, programme uptake rates remain suboptimal. Delivering cardiac rehabilitation (CR) in the community offers an alternative model of care that may help address the challenges that exist around uptake and accessibility of CR. Yet in comparison to traditional hospital based CR programmes less is known about the enablers and barriers that may be unique to attending community based CR programmes.

Purpose

This study aimed to identify enablers and barriers to attending and completing a community-based CR programme from the patient perspective.

Methods

Individuals who were referred to a 12 week, interdisciplinary, multi-component community-based CR programme were invited to take part in semi-structured interviews. Reasons for attending or not attending the programme and for completing or not completing the full programme were discussed. Purposeful sampling was used to obtain variation in age, gender, and level of engagement with the programme. Interviews were transcribed verbatim and analysed using framework analysis guided by the Capability Opportunity Motivation (COM B) Model and the Theoretical Domains Framework, to explore initial attendance and programme completion.

Results

Data saturation was achieved with sixteen participants. The majority of the identified barriers and enablers were common to both initial programme attendance and completion of programme. Having the social opportunity to receive support from peers, family members and staff was seen as an important enabler. While ease of access to a programme based in the community enabled attendance and completion, for some, distance to the cardiac rehabilitation centre was a barrier. Further barriers related to capability issues regarding poor physical health, time, work commitments and travel. Key motivational enablers included, beliefs around consequences, improved health status, knowledge, goals, intentions and personality. Identity was an important determinant of attendance as participants discussed their understanding of "what am I doing here?" Some participants identified themselves as the type of person who would benefit from the programme and others did not. For example, some felt the programme would suit those who needed motivation to enhance their health and some felt the programme was more or less suited to people of different ages and fitness levels.

Conclusion

The results suggest that interventions to enhance attendance at community-based CR need to address multiple factors related to capability, opportunity and motivation. While there is no one model of cardiovascular prevention and rehabilitation that will meet the needs of all patients, patients should be offered community based programmes as part of a choice of options that fit their needs and personal preferences.

Evaluation of a 10-week lifestyle and weight management programme on cardiovascular disease risk factors in a group of people living with obesity referred from a specialist bariatric clinic

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Health Service Executive Health and Wellbeing, Saolta University Healthcare Group

OnBehalf

Croí the West of Ireland Cardiac Foundation, Galway, Ireland and the National Institute for Prevention and Cardiovascular Health

Introduction

People living with obesity are at an increased risk of cardiovascular disease (CVD). While development of obesity is multifactorial, lifestyle modification is fundamental to obesity treatment and risk factor reduction. We sought to measure the effects of a structured lifestyle modification programme on the physical and mental health of people living with obesity.

Purpose

This study investigated the impact of a 10-week, community based, lifestyle modification programme on CVD risk factors in people living with obesity (BMI ≥35kg/m2 with a co-morbidity or BMI ≥40kg/m2) who were referred from a specialist bariatric service.

Methods

Delivered by an interdisciplinary team (Nurse, Dietitian & Physiotherapist) the programme included weekly group-based exercise sessions and health promotion workshops. A wide range of topics were addressed in workshops, including nutrition, food labels, emotional eating, physical activity, sedentary behaviour, stress management and CVD risk factor reduction. Outcomes were measured at initial and end of programme assessments.

Results

1122 people participated in the intervention between 2013 and 2019 with 78% (n = 877) completing the programme. At initial assessment 26.7% of participants had a diagnosis of type 2 diabetes; 37.3% were at high or very high risk of CVD; 44.7% were hypertensive and 31.4% had a history of depression. Mean BMI was 47.0kg/m2 with 56.4% of participants having a BMI &gt;45kg/m2. The intervention had significant positive impacts on key outcomes such as psychosocial health, lipid profiles, blood pressure, adiposity and cardiovascular fitness. One of the most significant outcomes observed was the improvement in psycho-social health. Scores of anxiety and depression, assessed using the HADS, decreased by 1.5 and 2.2 points respectively (p &lt;0.001). Mean EQ-VAS score increased by 11 points (p &lt;0.001). There were significant changes in total cholesterol levels with a mean reduction in total cholesterol from 4.69mmol/l to 4.54mmol/l (p &lt;0.001) and LDL cholesterol from 2.79mmol/l to 2.64mmol/l (p &lt;0.001). There were also significant improvements in blood pressure with mean systolic blood pressure reducing by 15.7mmHg (p &lt;0.001) and diastolic blood pressure reducing by 1.4mmHg (p &lt;0.001). For people with type 2 diabetes, there was an increase in those achieving the recommended HbA1c target (&lt;53mmol/l) from 47.6% to 57.4% (p &lt;0.001). Mean reduction in bodyweight was 2.0kg (p &lt;0.001), with 27.2% achieving a weight loss of &gt;3% of initial bodyweight. The percentage of participants achieving the recommended physical activity guidelines increased by 31% (p &lt;0.001).

Conclusions

A lifestyle modification programme delivered by an interdisciplinary team, aimed at individuals living with obesity, is not only acceptable to participants but also significantly reduces CVD risk factors. These findings should influence the design of future programmes and healthcare policies in Ireland and abroad.

How Can Biomechanical Multibody Models of Scoliosis Be Accurate in Simulating Spine Movement Behavior While Neglecting the Changes of Spinal Length?

This paper studies how biomechanical multibody models of scoliosis can neglect the changes of spinal length and yet be accurate in reconstructing spinal columns. As these models with fixed length comprise rigid links interconnected by rotary joints, they resemble polygonal chains that approximate spine curves with a finite number of line segments. In mathematics, using more segments with shorter lengths can result in more accurate curve approximations. This raises the question of whether more accurate spine curve approximations by increasing the number of links/joints can yield more accurate spinal column reconstructions. For this, the accuracy of spine curve approximation was improved consistently by increasing the number of links/joints, and its effects on the accuracy of spinal column reconstruction were assessed. Positive correlation was found between the accuracy of spine reconstruction and curve approximation. It was shown that while increasing the accuracy of curve approximations, the representation of scoliosis concavity and its side-to-side deviations were improved. Moreover, reconstruction errors of the spine regions separated by the inflection vertebrae had minimal impacts on each other. Overall, multibody scoliosis models with fixed spinal lengths can benefit from the extra rotational joints that contribute toward the accuracy of spine curve approximation. The outcome of this study leads to concurrent accuracy improvement and simplification of multibody models; joint-link configurations can be independently defined for the regions separated by the inflection vertebrae, enabling local optimization of the models for higher accuracy without unnecessary added complexity to the whole model.

The effect of lifestyle and risk factor modification on occlusive peripheral arterial disease outcomes: standard healthcare vs structured programme-for a randomised controlled trial protocol

Background

Peripheral arterial disease (PAD) affects more than 200 million of the global population. PAD represents a marker for premature cardiovascular events. Patients with PAD, even in the absence of a history of myocardial infarction or ischemic stroke, have approximately the same relative risk of death from cardiovascular causes as patients with a history of coronary or cerebrovascular disease. Despite the high prevalence of PAD and the strong association with cardiovascular morbidity and mortality, patients with PAD are less likely to receive appropriate treatment for their atherosclerotic risk factors than those who are being treated for coronary artery disease.

Atherosclerotic risk factor identification and modification play an important role in reducing the number of adverse outcomes among patients with atherosclerosis. Risk reduction therapy decreases the risk of cardiovascular mortality and morbidity in patients with PAD. In this study, we aim to evaluate the effectiveness of a lifestyle and risk factor modification intervention programme in achieving treatment goals for PAD risk factors.

Methods

This is a randomised, parallel group, active-control trial to compare the effectiveness of the risk factor modification intervention programme to standard healthcare in a tertiary vascular care centre, in the reduction of modified risk factors in PAD patients. The primary outcome of this study is to evaluate the effectiveness of a lifestyle and risk factor modification intervention programme in achieving treatment goals for PAD risk factors at 3 and 12 months. The secondary outcomes are to compare the impact of the programme on clinical outcomes in PAD patients at 12 months. Secondary outcomes include amputation-free survival, clinical improvement, haemodynamic improvement, need for revascularisation procedures, outcomes of revascularisation procedures, changes in quality of life and the incidence of adverse events.

Discussion

This study will provide clear evidence on the effectiveness of a lifestyle and risk factor modification intervention programme in achieving treatment goals for PAD risk factors, through a high-quality, well-powered clinical trial.

Trial registration

This trial was registered (11/07/2017) on the European Clinical Trials Database (EudraCT number 2017-002964-41) and ClinicalTrials.gov (NCT03935776) which was registered on 02 May 2019.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-021-05087-x.

Fabrication of polycaprolactone-silanated β-tricalcium phosphate-heparan sulfate scaffolds for spinal fusion applications

BACKGROUND CONTEXT

Interbody spinal fusion relies on the use of external fixation and the placement of a fusion cage filled with graft materials (scaffolds) without regard for their mechanical performance. Stability at the fusion site is instead reliant on fixation hardware combined with a selected cage. Ideally, scaffolds placed into the cage should both support the formation of new bone and contribute to the mechanical stability at the fusion site.

PURPOSE

We recently developed a scaffold consisting of silane-modified PCL-TCP (PCL-siTCP) with mechanical properties that can withstand the higher loads generated in the spine. To ensure the scaffold more closely mimicked the bone matrix, we incorporated collagen (Col) and a heparan sulfate glycosaminoglycan sugar (HS3) with increased affinity for heparin-binding proteins such as bone morphogenetic protein-2 (BMP-2). The osteostimulatory characteristic of this novel device delivering exogenous BMP2 was assessed in vitro and in vivo as a prelude to future spinal fusion studies with this device.

STUDY DESIGN/SETTING

A combination of cell-free assays (BMP2 release), progenitor cell-based assays (BMP2 bioactivity, cell proliferation and differentiation), and rodent ectopic bone formation assays was used to assess the osteostimulatory characteristics of the PCL-siTCP-based scaffolds.

MATERIALS AND METHODS

Freshly prepared rat mesenchymal stem cells were used to determine reparative cell proliferation and differentiation on the PCL-siTCP-based scaffolds over a 28-day period in vitro. The bioactivity of BMP2 released from the scaffolds was assessed on progenitor cells over a 28-day period using ALP activity assays and release kinetics as determined by enzyme-linked immunosorbent assay. For ectopic bone formation, intramuscular placement of scaffolds into Sprague Dawley rats (female, 4 weeks old, 120-150 g) was achieved in five animals, each receiving four treatments randomized for location along the limb. The four groups tested were (1) PCL-siTCP/Col (5-mm diameter×1-mm thickness), PCL-siTCP/Col/BMP2 (5 µg), (3) PCL-siTCP/Col/HS3 (25 µg), and (4) PCL-siTCP/Col/HS3/BMP2 (25 and 5 µg, respectively). Bone formation was evaluated at 8 weeks post implantation by microcomputed tomography (µCT) and histology.

RESULTS

Progenitor cell-based assays (proliferation, mRNA transcripts, and ALP activity) confirmed that BMP2 released from PCL-siTCP/Col/HS3 scaffolds increased ALP expression and mRNA levels of the osteogenic biomarkers Runx2, Col1a2, ALP, and bone gla protein-osteocalcin compared with devices without HS3. When the PCL-siTCP/Col/HS3/BMP2 scaffolds were implanted into rat hamstring muscle, increased bone formation (as determined by two-dimensional and three-dimensional µCTs and histologic analyses) was observed compared with scaffolds lacking BMP2. More consistent increases in the amount of ectopic bone were observed for the PCL-siTCP/Col/HS3/BMP2 implants compared with PCL-siTCP/Col/BMP2. Also, increased mineralizing tissue within the pores of the scaffold was seen with modified-tetrachrome histology, a result confirmed by µCT, and a modest but detectable increase in both the number and the thickness of ectopic bone structures were observed with the PCL-siTCP/Col/HS3/BMP2 implants.

CONCLUSIONS

The combination of PCL-siTCP/Col/HS3/BMP2 thus represents a promising avenue for further development as a bone graft alternative for spinal fusion surgery.

Investigation on the Effect of a Pre-Center Drill Hole and Tool Material on Thrust Force, Surface Roughness, and Cylindricity in the Drilling of Al7075

Drilling is one of the most useful metal cutting processes and is used in various applications, such as aerospace, electronics, and automotive. In traditional drilling methods, the thrust force, torque, tolerance, and tribology (surface roughness) are related to the cutting condition and tool geometry. In this paper, the effects of a pre-center drill hole, tool material, and drilling strategy (including continuous and non-continuous feed) on thrust force, surface roughness, and dimensional accuracy (cylindricity) have been investigated. The results show that using pre-center drill holes leads to a reduction of the engagement force and an improvement in the surface quality and cylindricity. Non-continuous drilling reduces the average thrust force and cylindricity value, and High Speed Steels HSS-Mo (high steel speed + 5–8% Mo) reduces the maximum quantity of cutting forces. Moreover, cylindricity is directly related to cutting temperature and is improved by using a non-continuous drilling strategy.

A miniature closed-loop deep brain stimulation device

This paper presents a miniature light-weight closed-loop deep brain stimulation (DBS) device that delivers on-demand stimulation current pulses by monitoring and analysing local field potentials. The device includes monitoring and DBS units, each designed and fabricated on a separate small round circuit board. The closed-loop DBS device has been successfully validated by injecting a pre-recorded neural signal into its input, and collecting and analysing its output. The monitoring unit has an amplification gain of 113 dB in frequency range of 0.7-50 Hz. The DBS unit gives on-demand stimulation current pulses of duration 90 μs, frequency 130 Hz, and amplitude 200 μA. The total weight of the device including a 3V coin battery is 1.41 g. The diameter of the device is 11.4 mm. This portable head-mountable device is suitable for use in pre-clinical trials with small laboratory animals.

An Exploration of Faculty Experiences With Open Access Journal Publishing at Two Canadian Comprehensive Universities

INTRODUCTION: This exploratory study was intended to shed light on Canadian academics’ participation in, knowledge of and attitudes towards Open Access (OA) journal publishing. The primary aim of the study was to inform the authors’ schools’ educational and outreach efforts to faculty regarding OA publishing. The survey was conducted at two Canadian comprehensive universities: Brock University (St. Catharines, Ontario) and Wilfrid Laurier University (Waterloo, Ontario) in 2014. METHODS: A Web-based survey was distributed to faculty at each university. The data was analyzed using descriptive statistics. LIMITATIONS: Despite the excellent response rates, the results are not generalizable beyond these two institutions. RESULTS: The Brock response rate was 38 percent; the Laurier response rate was 23 percent from full-time faculty and five percent from part-time faculty. Brock and Laurier faculty members share common characteristics in both their publishing practices and attitudes towards OA. Science/health science researchers were the most positive about OA journal publishing; arts and humanities and social sciences respondents were more mixed in their perceptions; business participants were the least positive. Their concerns focused on OA journal quality and associated costs. CONCLUSION: While most survey respondents agreed that publicly available research is generally a good thing, this study has clearly identified obstacles that prevent faculty’s positive attitudes towards OA from translating into open publishing practices. INTRODUCTION : Cette étude exploratoire tente de mieux comprendre la participation, les connaissances et les attitudes des universitaires canadiens envers la publication en libre accès. Le but premier de cette étude est d’éclairer les campagnes éducatives et de sensibilisation concernant la publication en libre accès auprès des institutions des auteurs. Un sondage a été mené en 2014 à deux universités à vocation générale canadiennes : Brock University (St. Catherine, Ontario) et Wilfrid Laurier University (Waterloo, Ontario). MÉTHODES : Un sondage en ligne a été envoyé au corps professoral de chaque université. Les données ont été analysées à l’aide de statistiques descriptives. LIMITES : Malgré l’excellent taux de réponse, les résultats ne peuvent être généralisés au-delà des deux universités. RÉSULTATS : Le taux de réponse de Brock était de 38%; celui de Laurier était de 23% pour les professeurs à temps plein et 5% pour les professeurs à temps partiel. Les professeurs des deux universités partagent quelques caractéristiques quant à leurs pratiques et attitudes envers le libre accès. Les chercheurs en médecine et en sciences de la santé étaient les plus positifs envers la publication dans des revues en libre accès; les répondants des arts, sciences humaines et sciences sociales avaient des opinions mixtes; les participants en gestion étaient les moins positifs. Leurs inquiétudes portaient sur la qualité des revues en libre accès et les coûts associés. CONCLUSION : Malgré le fait que la plupart des répondants croient qu’il est bon que la recherche soit disponible au grand public, cette étude identifie clairement des obstacles qui empêchent les professeurs de passer d’attitudes positives envers le libre accès à des pratiques concrètes de publication ouverte.

Thermal Stress Flow Analysis in Fabrication of Acetabular Shells Using SLM

<p>Additive Manufacturing (AM), more popularly known as 3D Printing, is a process for producing functional artifacts by adding layers of materials from data generated directly from 3D solid CAD models. Additive Manufacturing (AM) is the formalized term for what used to be called Rapid Prototyping and what is commonly referred to as 3D Printing. The key to how AM works is that parts are made by adding layers of material; each layer corresponding to a thin cross-section of the part derived from the original CAD data. Although most AM machines produce parts using polymers, there are an increasing number of machines that can directly fabricate in metals. The majority of these machines fabricate from raw material in powder form using a directed energy beam to create a local melt zone. Total hip replacement is recommended for people who have medical issues related to excessive wear of the acetabular, osteoarthritis, accident or age. Researches have shown that large numbers of hip arthroplasties (where the articular surface of a musculoskeletal joint is replaced), hip remodelling, or realignment are carried out annually and will increase in the next few decades. Manufacturing of acetabular shells by using AM is a promising and emerging method that has a great potential to improve public health. Lost wax casting or investment casting is currently used to produce acetabular shells followed by lengthy and complex secondary processes such as machining and polishing. Living organs and medical models have intricate 3D shapes that are challenging to identity in X-ray CT images. These images are used for preparing treatment plans to improve the quality of the surgeries regarding waiting and surgery time per procedure and care regime. For instance, a limited number of hip replacement procedures can be carried out on each acetabulum due to a decrease of bone thickness. Rapid prototyping is a suitable treatment planning tool in complex cases to enhance the quality of surgical procedure and provide long-term stability that can be used to customize the shape and size of the acetabular shell. In this paper, to analyse the manufacturing of a prosthetic acetabular shell, built-up lines resulting from a thermal stress flow and process stopping during the selective laser melting (SLM) AM process, with regarding Gibbs free energy, interfacial energy, and equilibrium temperature will be discussed. Geometrical measurements showed 1.59% and 0.27% differences between the designed and manufactured prototype for inside and outside diameter respectively. Experimental results showed that thermal stress flow in outer surfaces are compressive, but for inner surfaces are tensile, so built-up lines in inner and outer surfaces appear as a groove and dent respectively. The results also indicate that SLM is an accurate and promising method for fabrication of acetabular cup.</p>

Advanced auricular prosthesis development by 3D modelling and multi-material printing

We investigate the use of medical imaging, digital design and 3D printing technologies as a viable means of reproducing a person’s anatomy, with the intension of producing a working, patient specific prosthesis. This approach offers several advantages over traditional techniques, as data capture is non-intrusive, models can be made using quantitative methodologies, design iterations can be digitally stored for future reproduction, and additive manufacturing ensures no loss of quality when converting the digital model into a physical part. We also present a combined model segmentation with multi-material printing approach to increase the colour complexity of the final model. When combined with multi-material printing using elastic materials, our approach provides a comprehensive strategy to accurately realising mimic of both skin pigmentation and the tactile feel of human tissues. Ultimately, we believe our approach provides an innovative strategy for prosthesis production which could have considerable potential for implementation in a clinical setting.

3D Printing of a Photo-thermal Self-folding Actuator

The demand for rapid and accurate fabrication of light-weight, biocompatible, and soft actuators in soft robotics has perused researchers to design and fabricate such products by rapid manufacturing techniques. The self-folding origami structure is a type of soft actuator that has applications in micro electro mechanical systems, soft electronics, and biomedical devices. 3-dimentional (3D) printing is a current manufacturing process that can be used for fabrication of involute soft self-folding products by means of shape memory polymer materials. This paper presents, for the first time, a method for developing a photo thermal self-folding soft actuator using a 3D bioplotter. Easily accessible and inexpensive pre-strained polystyrene is opted for the backbone of actuator. The polystyrene film (PS) is then structured in a hand shape gripper. Chitosan hydrogel and carbon black ink were combined for printing active hinges on the hand gripper. Various active hinges with different widths and thicknesses were printed on the hand gripper using the 3D bioplotter. An infra-red (IR) heating lamp was placed at a reasonable distance to emit IR light uniformly on the hand gripper. The temperature distribution on the hand gripper was observed using a thermographic camera and the bending angles of the samples were recorded by a video camera. It was observed that the bending angles of the hand fingers depend on factors such as the intensity of the heat flux generated by the IR light intensity, distance, onset temperature, geometry of the fingers such as width and thickness, and area of the hinges.

A low carbon footprint approach to the reconstitution of plastics into 3D-printer filament for enhanced waste reduction

<p>In this study we aim to investigate recycling of waste plastics products into filaments for use in a typical FDM 3D printing system. We investigate the parameters relating to control of the filament thickness to a variety of different plastic types, which include HDPE and ABS. Following filament generation, parameters were investigated to optimise the print parameters to produce a variety of demonstration models, which test the print resolution. Results suggest that the proposed supply chain can allow for highly repeatable ABS and HDPE filament generation with a diameter of 1.74 ± 0.1mm and 1.65 ± 0.1mm respectively. Ultimately, the production of usable filaments can provide a viable means of consuming waste plastics and reducing the burden of increased landfill. </p>

Analysis of compressive load on intervertebral joint in standing and sitting postures

BACKGROUND

There have been some disagreements on the comparison of disc pressures in the standing and sitting postures in literature. Most research on in vivo pressure needle measurement found higher disc pressure in sitting than in standing. The disc pressure data can help to advocate better postures for clinical advice.

OBJECTIVE

The aim of this paper is to develop a procedure to study the compressive load on intervertebral joint in the standing and sitting postures through the approach of motion capture and musculoskeletal modeling.

METHODS

The marker data of six subjects performing various standing and sitting postures was obtained during the motion capture experiment and used to train the musculoskeletal model with an enhanced discretized spine developed for subject in the inverse and forward simulations.

RESULTS

Compressive loads on L3-L4 and L4-L5 joints are found higher in upright sitting than in upright standing. Slumped sitting, cross-legged sitting and flexion sitting can introduce higher compressive loads on intervertebral joints compared with upright sitting.

CONCLUSIONS

These findings indicate the effects of standing and sitting postures on the spinal joint loads. The results can provide doctors and therapists with more information on clinical advice on better postures for people with spinal problems.

The concentration-dependent aggregation of Ag NPs induced by cystine

Cystine is widely used in cell culture media. Cysteine, the reduced form of cystine, is widely used to scavenge dissolved Ag in eco-toxicological studies to differentiate dissolved vs. nanoparticle uptake and toxicity. However, little is known about the impact of cysteine and cystine on the aggregation behavior of Ag NPs, in particular as a function of Ag NP concentration. Herein, we investigate how cystine (0-300μM) affects the stability of citrate-, polyvinylpyrrolidone-, and polyethylene glycol-coated silver nanoparticles (cit-Ag NPs, PVP-Ag NPs and PEG-Ag NPs, respectively) with and without Suwannee River fulvic acid (SRFA) as a function of Ag NPs concentration using UV-vis spectroscopy at environmentally and ecotoxicologically relevant Ag NP concentrations (ca. 125-1000μgL(-1)). The results demonstrate, for the first time, the concentration-dependent aggregation of cit-Ag NPs in the presence of cystine with a shift in the critical coagulation concentration (CCC) to lower cystine concentrations at lower cit-Ag NP concentrations. At the highest cit-Ag NP concentration (1000μgL(-1)), reaction limited aggregation was only observed and no CCC was measured. SRFA slowed the aggregation of cit-Ag NPs by cystine and aggregation occurred in reaction limited aggregation (RLA) regime only. No CCC value was measured in the presence of SRFA. Cystine replaces citrate, PVP and PEG coatings, resulting in aggregation of both electrostatically and sterically stabilized Ag NPs. These findings are important in understanding the factors determining the behavior of Ag NPs in cell culture media. Also due to the similarity between cystine and cysteine, these results are important in understanding the uptake and toxicity of Ag NPs vs. Ag ions, and suggest that the reduction of the toxicity of Ag NPs in the presence of cysteine could be due to a combined effect of scavenging Ag(+) ions and Ag NP aggregation in the presence of cysteine.

Attitudes to outcomes measured in clinical trials of cardiovascular prevention

BACKGROUND

Selecting outcome measures in cardiovascular prevention trials should be informed by their importance to selected populations. Major vascular event outcomes are usually prioritized in these trials with considerably less attention paid to cognitive and functional outcomes.

AIM

To examine views on importance of outcome measures used in clinical trials.

DESIGN

Cross-sectional survey.

METHODS

Of 367 individuals approached, 280 (76%) participated: outpatients attending cardiovascular prevention clinics (n = 97), active retirement groups members (n = 75), medical students (n = 108). Participants were asked to rank, in order of importance, outcome measures, which may be included in cardiovascular prevention trials. Results were compared between two groups: <65s (n = 157) and ≥65s (n = 104).

RESULTS

When asked what outcomes were most important to measure in cardiovascular prevention trials, respondents reported: death (31.6%) stroke (28.5%), dementia (26.9%), myocardial infarction (MI) (7.9%) and requiring nursing home (NH) care (5.1%). When asked the most relevant outcomes regarding successful ageing respondents reported; maintaining independence (32.4%), avoiding major illness (24.3%), good family life (23.6%), living as long as possible (15.8%), avoiding NH care (3.1%) and contributing to society (0.8%) as most important. When asked what outcome concerned them most about the future, respondents reported: dementia (32.6%), dependence (30.4%), death (12.8%), stroke (12.5%), cancer (6.2%) requiring NH care (4.8%) and MI (0.7%). Maintaining independence was considered most important in younger and older cohorts.

CONCLUSION

Cognitive and functional outcomes are important patient-relevant outcomes, sometimes more important than major vascular events. Incorporating these outcomes into trials may encourage patient participation and adherence to preventative regimens.

A Novel Classification and Online Platform for Planning and Documentation of Medical Applications of Additive Manufacturing

Additive manufacturing technologies are widely used in industrial settings and now increasingly also in several areas of medicine. Various techniques and numerous types of materials are used for these applications. There is a clear need to unify and harmonize the patterns of their use worldwide. We present a 5-class system to aid planning of these applications and related scientific work as well as communication between various actors involved in this field. An online, matrix-based platform and a database were developed for planning and documentation of various solutions. This platform will help the medical community to structurally develop both research innovations and clinical applications of additive manufacturing. The online platform can be accessed through http://www.medicalam.info .

Papillomaviral DNA sequences are not amplifiable from canine subungual squamous cell carcinomas

AIM

To determine if papillomaviral DNA is more frequently present within canine subungual squamous cell carcinomas (SCCs) than in non-SCC digit lesions.

METHODS

Total DNA was extracted from 23 canine subungual SCCs and 23 non-SCC digit lesions. The presence of amplifiable DNA within each sample was confirmed by amplifying a section of the glyceraldehyde-3-phosphate dehydrogenase (GADPH) gene. Two different consensus PCR primer sets were used to amplify papillomaviral DNA from the samples.

RESULTS

The consensus primers only amplified papillomaviral DNA from the positive control samples. None of the 46 canine digit samples contained DNA that was amplifiable by the consensus PCR primers.

CONCLUSION

Papillomaviruses are unlikely to be a significant cause of canine subungual SCCs.

CLINICAL RELEVANCE

While circumstantial evidence suggests that canine subungual SCCs could develop due to papillomaviral infection, this study did not reveal any evidence to support papillomaviral aetiology of these neoplasms.

Interaction of TAPP adapter proteins with phosphatidylinositol (3,4)-bisphosphate regulates B cell activation and autoantibody production (159.5)

Activation of PI3-kinase enzymes through the BCR is essential for B cell development and function. Active PI3Ks generate D3 phosphoinositide PI(3,4)P2 that bind to signaling molecules such as TAPP (Tandem PH domain containing protein) adaptor via their C terminal PH domain. This interaction leads to translocation of TAPPs to the plasma membrane. However, the role of TAPP adaptors in regulating PI3K signaling in B cell is not completely understood. We have performed studies on TAPP mutant mice, where a mutation was introduced to the C terminal domain of both TAPP1 and TAPP2 to determine the effect of uncoupling TAPPs from PI(3,4)P2. The studies showed an enhanced B cell activation and elevated serum antibody levels in these mice, suggesting an inhibitory role associated with TAPPs in B cells. To test whether the aberrant responses observed in B cells leads to autoimmunity in these animals, we analyzed their serum and observed a progressive increase in anti-dsDNA antibodies in the aging cohort. This along with other observed characteristics such as the presence of anti-nuclear antibodies within the serum, progressive development of lymphopenia and glomerulonephritis in aged mice is reminiscent of lupus. We are currently working to define the cellular interactions involved in this autoimmune phenotype and the signaling mechanism associated with the inhibitory role of TAPPs.

Biomimetic composite coating on rapid prototyped scaffolds for bone tissue engineering

The objective of this present study was to improve the functional performance of rapid prototyped scaffolds for bone tissue engineering through biomimetic composite coating. Rapid prototyped poly(ε-caprolactone)/tri-calcium phosphate (PCL/TCP) scaffolds were fabricated using the screw extrusion system (SES). The fabricated PCL/TCP scaffolds were coated with a carbonated hydroxyapatite (CHA)-gelatin composite via biomimetic co-precipitation. The structure of the prepared CHA-gelatin composite coating was studied by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. Compressive mechanical testing revealed that the coating process did not have any detrimental effect on the mechanical properties of the scaffolds. The cell-scaffold interaction was studied by culturing porcine bone marrow stromal cells (BMSCs) on the scaffolds and assessing the proliferation and bone-related gene and protein expression capabilities of the cells. Confocal laser microscopy and SEM images of the cell-scaffold constructs showed a uniformly distributed cell sheet and accumulation of extracellular matrix in the interior of CHA-gelatin composite-coated PCL/TCP scaffolds. The proliferation rate of BMSCs on CHA-gelatin composite-coated PCL/TCP scaffolds was about 2.3 and 1.7 times higher than that on PCL/TCP scaffolds and CHA-coated PCL/TCP scaffolds, respectively, by day 10. Furthermore, reverse transcription polymerase chain reaction and Western blot analysis revealed that CHA-gelatin composite-coated PCL/TCP scaffolds stimulate osteogenic differentiation of BMSCs the most, compared with PCL/TCP scaffolds and CHA-coated PCL/TCP scaffolds. These results demonstrate that CHA-gelatin composite-coated rapid prototyped PCL/TCP scaffolds are promising for bone tissue engineering.

One box to search them all

Purpose

The purpose of this paper is to present how, in May 2008, the Ad Hoc Committee on Federated Search was formed to prepare a preliminary report on federated searching for a special meeting of Librarians Academic Council at Memorial University Libraries. The primary purpose is to discuss current implementation of federated searching at this institution, explore what other institutions have done, examine federated search technologies, and offer recommendations for the future of this resource.

Design/methodology/approach

Information was drawn from a recent usability study, an informal survey was created, and a literature/technology review was conducted.

Findings

These four recommendations were proposed and unanimously accepted: actively develop the current federated search implementation by developing a web presence supporting “federated search in context”, re‐evaluating the need for consortial purchase of a federated search tool, continuing to assess the current federated search marketplace with an eye to choosing a next‐generation federated search tool that includes effective de‐duping, sorting, relevancy, clustering and faceting, and that the selection, testing, and implementation of such a tool should involve broad participation from the Memorial University Libraries system.

Originality/value

Provided is an inside look at one institution's experience with implementing a federated search tool. The paper should be of interest to anyone working in academic libraries, particularly the areas of administration, public services, and systems.

A new look at chronic fatigue syndrome/myalgic encephalomyelitis

It has been 3 years since the Chief Medical Officer reported on chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) and the time has come for a thorough investigation by an All Party Group drawn from the House of Commons and the House of Lords. We have received many written submissions and are engaged in taking oral evidence in 2-h sessions, which we open to the public as well as interested groups. The group has received a fantastic response to its requests for written evidence over the past few months. Questions that arise for a government response are the lack of provision and support for patients with CFS/ME, the issue of the clinical definition of CFS/ME, the need for a diagnostic test for CFS/ME, effectiveness of the National Institute for Clinical Excellence guidelines, and criteria used to decide which treatments are best for patients with CFS or myalgic encephalomyelitis.

A novel artificial prosthetic replacement for the proximal interphalangeal joint of the hand--from concept to prototype

This article describes the development of a proximal interphalangeal (PIP) joint prosthesis based on the principles of replicating anatomical surface components, the use of macrolocking intramedullary stem and the use of a cobalt-chrome alloy material. The design features are intended to obtain an optimal range of motion while retaining stability and longevity. The final prototype, for which a patent has been filed, is described.

In vivo evaluation of nicotine lyophilised nasal insert in sheep

The nasal route offers an attractive means of delivering a drug directly to the systemic circulation and avoiding hepatic first-pass metabolism, although rapid mucociliary clearance can be detrimental to nasal absorption. The in vitro and in vivo characteristics of a nasal insert formulation prepared by lyophilisation of a viscous HPMC gel solution designed to overcome this problem were studied. In vitro release of nicotine from the lyophilised insert was compared with powder and spray formulations. Stability and characterisation studies were carried out using dynamic vapour sorption, scanning electron microscopy and HPLC analysis. Nicotine formulations were administered to eight wether sheep in a randomised four-way cross-over study, and plasma nicotine assessed comparing the nasal insert formulation with conventional nasal powder, nasal spray and IV doses. In vitro release studies demonstrated prolonged nicotine release from the nasal insert formulation compared to a powder and liquid. In vivo plasma profiles appeared to show prolonged plasma nicotine levels compared to the conventional formulations, although T(max), C(max) and AUC parameters for the insert were not significantly different due to high variability in the pharmacokinetic data. In conclusion, the nasal insert displayed a promising prolonged plasma profile, which must be investigated further to provide statistical significance to prove the effect.