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1.
Cell Mol Biol (Noisy-le-grand) ; 69(6): 208-213, 2023 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-37605569

RESUMO

This study aimed to identify whether there are elevations or declines in specific plasma lipids in intertrochanteric fracture (ITF) patients which might serve as potential biomarkers for assessing the severity of trauma, or therapeutic targets for controlling post-traumatic responses. Ten metal work removal patients were enrolled. Their preoperative blood samples served as the control group (C group). Their 24-hour postoperative blood samples served as the moderate trauma group (M group). The ITF group was composed of 12 intertrochanteric fracture patients. A total of 707 lipid species were identified from 32 plasma samples (10 controls, 10 moderate trauma and 12 ITF samples). We first identified 31 lipids that were elevated and 6 lipids that were decreased in the more severe trauma group in aged patients, with an especially strong relationship among 14 lipids that are candidates as markers for trauma severity evaluation. Fourteen lipids were identified as potential markers of bone trauma. The definition of important lipids in trauma may not only provide guidance for the formulation of optimum ITF operation time, but may also have importance in other traumatic models, and in further understanding the components of the systemic inflammatory response for new drug targets.


Assuntos
Lipídeos , Humanos , Idoso , Biomarcadores , Período Pós-Operatório
2.
J Synchrotron Radiat ; 29(Pt 2): 377-385, 2022 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-35254300

RESUMO

Crystal monochromators are often the primary optics in hard X-ray synchrotron beamlines. Management of power load is central to their design. Strict requirements on stability and deformation are to be met, as new-generation synchrotron sources deliver brighter beams of X-rays. This article sets out to illustrate an overall picture of the deformation caused by heat load in a cryo-cooled Si crystal monochromator using first principles. A theoretical model has been developed to predict the temperature distribution and surface deformation by applying intrinsic properties of Si material and the cooling system parameters. The model explains the universal behaviour of crystal slope error versus absorbed power; it has been benchmarked against experimental data and used to interpret finite-element analysis of cryogenically cooled crystals.

3.
BMC Musculoskelet Disord ; 23(1): 693, 2022 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-35864497

RESUMO

BACKGROUND: Lumbar vertebroplasty via several different types of extrapedicular approach has been reported with acceptable clinical results yet the anatomical basis for its safety is not fully explored. Injury to the lumbar arteries (LAs) is one of the most important potential complications. However, anatomical research on the course and variability of this structure is lacking. To investigate the anatomical feasibility of percutaneous vertebroplasty for lumbar osteoporotic vertebral compression fractures via a unilateral Extrapedicular approach. METHODS: A total of 300 LAs of 30 patients with non-spinal disorders were retrospectively analyzed by computed tomographic angiography (CTA). The lateral aspect of the vertebral body was divided into 9 zones of approximately equal area. The anatomy and orientation of LAs were analyzed in detail. RESULTS: LAs were most commonly found in the middle third of the body (zones 4, 5, and 6); the upper 1/3 of the vertebral body had LAs distributed only anteriorly and laterally (zones 1 and 2). No arteries were observed in the postero-superior segment (zone 3). From L1 to L3 an arched pattern predominated. At L4 an inferior oblique pattern (antero-superior to postero-inferior) predominated. Limited CTA visualization at L4 and particularly L5 as well as greater anatomical variation means that there is more uncertainty at these levels. CONCLUSION: From L1 to L3, the posterior superior segment (zone 1) of the vertebral body appears to be a safe area with low risk of arterial injury. This has relevance for design of a safe lumbar vertebral extrapedicular approach.


Assuntos
Fraturas por Compressão , Fraturas por Osteoporose , Fraturas da Coluna Vertebral , Vertebroplastia , Angiografia , Estudos de Viabilidade , Fraturas por Compressão/cirurgia , Humanos , Vértebras Lombares/diagnóstico por imagem , Vértebras Lombares/lesões , Vértebras Lombares/cirurgia , Fraturas por Osteoporose/diagnóstico por imagem , Fraturas por Osteoporose/cirurgia , Estudos Retrospectivos , Fraturas da Coluna Vertebral/diagnóstico por imagem , Fraturas da Coluna Vertebral/cirurgia , Resultado do Tratamento
4.
BMC Musculoskelet Disord ; 22(1): 566, 2021 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-34154594

RESUMO

BACKGROUND: Patient Reported Outcome Measures (PROMs) are widely used in Europe and North America in a variety of areas including research, clinical governance, clinical registries and insurance ascertainment. The aim of this study was to assess commonly used knee and hip PROMs among Chinese surgeons and to gain an insight into their impact on evaluation of clinical outcomes. METHODS: 1. A systematic literature search of databases Medline, EMBASE, CINAHL and CNKI was performed from the earliest records to 22/07/2020 for knee instruments and 22/08/2020 for hip instruments, to retrieve Chinese Mandarin cross culturally adapted and validated knee and hip PROMs. 2. An 11-item electronic questionnaire was then designed under four domain categories. The survey was distributed via a ubiquitous online social media platform to orthopaedic surgeons. Responses were collected and analyzed. Output from 1. was used to populate parts of the survey questionnaire. RESULTS: The systematic online search yielded a total of 41 evaluation instruments, (10 hip and 31 knee); all of which were incorporated as response options. 234 viable questionnaires were retrieved with the largest group representing attending surgeons. 59.0% were familiar with the concept of PROMs among which 78.4% reported to have used PROMs themselves. In order of frequency of use, PROMs were purposed for clinical assessment (55.6%), research (40.7%), health regulation policies (18.6%) and insurance service requirements (10.6%). Implementation was prompted by both departmental (43.4%) and institutional policy (34.5%). 89.4% of PROMs users reported difficulties in the use of PROMs, with major barriers including license fees, limited access, inadequate training and burden of fill-out time (all > 40%). CONCLUSION: There is evidence of limited familiarity with knee and hip PROMs among orthopaedic surgeons. Barriers to their use are significant. Development of a Chinese language PROMs database would be helpful.


Assuntos
Cirurgiões Ortopédicos , China/epidemiologia , Europa (Continente) , Humanos , América do Norte , Medidas de Resultados Relatados pelo Paciente , Qualidade de Vida , Inquéritos e Questionários
5.
J Pediatr Orthop ; 34(2): 150-4, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24172664

RESUMO

BACKGROUND: Fractures of the scaphoid are uncommon in the pediatric population. Despite their rarity, a significant number of children are referred to the fracture clinic for a suspected scaphoid fracture. The aim of this study was to report on the current incidence, pattern of injury, and the long-term outcomes following this injury in the pediatric population. METHODS: Analysis of all pediatric scaphoid fractures presenting to a tertiary pediatric hospital (aged 13 y and under) over a 5-year period was performed. The case notes, radiographs, and other imaging studies for these patients were reviewed. Long-term functional outcome was assessed using Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire. RESULTS: Fifty-six patients of the 838 (6.7%) referred for a suspected scaphoid fracture were identified as having a confirmed diagnosis of a scaphoid fracture, giving an average annual incidence of 11 per 100,000. This group consisted of 39 boys (70%) and 17 girls (30%). The average age of incidence in boys was 12.2 years and in girls was 10.3 years (P<0.001). No scaphoid fractures were observed in boys below the age of 11 years and in girls below the age of 9 years. The most common type of fracture was a distal pole fracture (45 patients). One patient sustained a proximal pole fracture and went on to develop a nonunion. The duration of treatment in cast was shorter in distal pole fractures than in other types (P<0.001). At a mean follow-up of 70 months (range, 46 to 104 mo), 60% reported no limitation or impact when reporting a range of daily functional activities (mean DASH score=3.0). CONCLUSIONS: There is a suggestion that the overall incidence of scaphoid fractures in the pediatric population is increasing, but children aged 13 years and under continue to maintain a distinct fracture pattern when compared with adolescents and adults. The majority involves the distal third of the scaphoid and carries a good prognosis with conservative management. LEVEL OF EVIDENCE: Prognostic study, Level 4.


Assuntos
Fraturas Ósseas/epidemiologia , Incidência , Osso Escafoide/lesões , Traumatismos do Punho/epidemiologia , Adolescente , Moldes Cirúrgicos , Criança , Feminino , Fraturas Ósseas/diagnóstico por imagem , Fraturas Ósseas/terapia , Humanos , Masculino , Prognóstico , Radiografia , Estudos Retrospectivos , Osso Escafoide/diagnóstico por imagem , Escócia/epidemiologia , Inquéritos e Questionários , Traumatismos do Punho/diagnóstico por imagem , Traumatismos do Punho/terapia
6.
J Hum Lact ; : 8903344241254344, 2024 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-38826038

RESUMO

Pediatricians need to be knowledgeable to adequately carry out their role in the support of breastfeeding, so assessing their knowledge of breastfeeding is vitally important. There are not English language validated questionnaires for pediatricians in the literature; however, in Spanish and Portuguese, there is the Breastfeeding Knowledge Survey (ECoLa, derived from Encuesta de Conocimientos en Lactancia). Our goal is to translate the ECoLa into English. The original survey consisted of true/false questions, including one with an image of a breastfeeding baby, multiple-choice questions featuring clinical cases, and two open-ended short questions. We used a translation approach that incorporated both forward and backward translations and a multidisciplinary committee to evaluate the translation process. During translation, four Spanish versions and seven English versions were considered prior to consensus approval of the final survey. The intraclass correlation coefficient between the English questionnaire and the original Spanish version was 0.85 (95% CI [0.60, 0.95]). A sample of 51 participants completed the survey, resulting in a Cronbach's alpha of 0.78 for the English version (95% CI [0.70, 0.86]). The Breastfeeding Knowledge Survey is now accessible under a Creative Commons license, permitting its free re-use.

7.
J Mech Behav Biomed Mater ; 151: 106369, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38184931

RESUMO

Additively manufactured lattices have been adopted in applications ranging from medical implants to aerospace components. For solid AM components, the effect of build parameters has been well studied but comparably little attention has been paid to the influence of build parameters on lattice performance. For this project, the main aim was to evaluate static compressive mechanical performance of regular and stochastic lattices as a function of build parameters. The second aim was to compare strut dimensions of the metal lattice structures as build parameters were changed. Both regular and stochastic lattices were fabricated with a designed strut diameter of either 200 µm or 300 µm on a laser powder bed fusion machine. A range of laser power (140-180 W), scan speed (1700-2100 mm/s), and laser offset (0-45 µm) were used in fabricating each lattice. Compression tests were performed following the ISO 13314 (2011) standard to measure modulus, yield strength, and ultimate compressive strength values. Laser power adjustments produced the most significant effect on lattice performance. A change of 50 W resulted in roughly a 2X increase in maximum load and modulus for both regular and stochastic lattice structures. Regular lattice structures had a higher mechanical response during the mechanical evaluation. Internal strut diameters varied between build parameters as well, with laser offset adjustments producing the most noticeable change in strut geometry between lattice samples. These findings suggest that build parameter optimization, in lieu of using OEM parameters developed for solid structures, is necessary to ensure the optimum mechanical performance of AM lattice structures.


Assuntos
Próteses e Implantes , Titânio , Titânio/química , Teste de Materiais , Porosidade , Estresse Mecânico
8.
3D Print Med ; 10(1): 11, 2024 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-38587709

RESUMO

Multi-laser Additive Manufacturing systems hold great potential to increase productivity. However, adding multiple energy sources to a powder bed fusion system requires careful selection of a laser scan and inert gas flow strategy to optimize component performance. In this work, we explore four different laser scan and argon flow strategies on the quasi-static compressive mechanical response of Body Centered Cubic lattices. Three strategies employ a swim lane method where laser pathing tends to progress parallel to argon flow. Method one only uses a single laser while method two uses four, both with the laser path working against the argon flow. The third method uses four lasers, each operating in their own lane like the second method, but the laser pathing progresses with the argon flow. The fourth method has all four lasers operating in quadrants and the laser pathing trends against the argon flow.The single-laser strategy generally had the lowest mechanical responses compared to the other three strategies. A quadrant strategy generally had the highest quasi-static mechanical responses and was at least 25% greater in stiffness, yield force, ultimate force, and energy absorption when compared to the single laser strategy. However, the four-laser swim strategy where the laser pathing tends against the argon flow was found to be statistically similar to the quadrant strategy. It is hypothesized that spatter introduced onto the powder layer from the melt pool and particle entrainment may be worse for laser pathing which trends with the argon flow direction. Additionally, the additional energy added to the build volume helps to mitigate inter-layer cool time which reduces temperature gradients. This shows that multi-laser AM systems have an impact on part performance and potentially shows lattices built with multi-laser AM systems may have certain advantages over single-laser AM systems.

9.
Cureus ; 16(4): e58641, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38770456

RESUMO

Background and objective Thoracolumbar spine trauma (TST) is frequently associated with spinal cord injury and other soft tissue and bony injuries. The management of such injuries requires an evidence-based approach. This study used the Appraisal of Guidelines for Research and Evaluation (AGREE) II instrument to assess the methodological quality of clinical guidelines for the management of TST published by the Congress of Neurological Surgeons (CNS). Methods All clinical guidelines on TST published by CNS until 2020 were assessed. Five appraisers from three international centers evaluated the quality of eligible clinical guidelines by using AGREE II. Mean AGREE II scores for each domain were determined. In higher-quality domains, the scores for individual items were analyzed. Results A total of 12 guidelines published by CNS on TST were assessed. Mean scores for all six domains were as follows: Scope and Purpose (75.2%), Stakeholder Involvement (45.4%), Rigor of Development (57.0%), Clarity of Presentation (58.7%), Applicability (16.9%), and Editorial Independence (64.1%). The mean score for the overall quality of all CNS guidelines was 52.9% [95% confidence interval (CI): 52.2-53.5%]. The overall agreement among appraisers was excellent [intra-class correlation coefficients (ICCs) for each guideline ranged from 0.903 to 0.963]. Conclusions CNS guidelines for the management of TST demonstrated acceptable quality across most domains; however, the domains of Applicability and Stakeholder Involvement could be further improved in future guideline updates. The assessors concluded that all guidelines could still be recommended for clinical practice with or without modifications.

10.
J Surg Educ ; 81(1): 76-83, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37852874

RESUMO

OBJECTIVE: This study aimed to record and analyze surgical resident trainee time allocation among junior doctors in China in order to understand the training environment and optimize realistic training and patient care objectives. DESIGN: Multicenter observational time and motion study. SETTING: Multicenter, carried out in 5 tier 3 public hospitals in 5 provinces across China. PARTICIPANTS: Surgical resident trainees at various stages of training were eligible to enter the study, total n = 44. Registered nurses were eligible to be observers, n = 4 from each hospital.  An expert team comprising 4 chief surgeons and 10 surgical residents participated in establishing the clinical activity list. RESULTS: Participants were observed during working hours (08.00-17.00) for 10 consecutive working days and time spent on different activities were recorded. Work patterns between hospitals were often dissimilar. Most time was spent on direct patient care (34.1%; 95% CI, 28.0%-40.1%) followed by indirect patient care (24.4%; 95% CI, 15.5%-33.2%), scholarly activity (21.1%; 95% CI, 13.7%-28.5%) and other (20.4%; 95% CI, 14.1%-26.8%). Subcategory analysis showed that the amount of time spent each day performing certain tasks was 137 minutes for operating theatre tasks, 103 minutes for medical record-keeping, 25 minutes for direct patient contact, 20 minutes being taught, 12 minutes teaching others, 12 minutes hand-over time, and 0 minutes of outpatient clinic attendance. Inter-observer reliability of 96.5% was obtained prior to recordings. CONCLUSIONS: Chinese surgical resident work patterns fall within the range found in other international studies albeit with some exceptions. The training environment appears broadly suitable for competence-based surgical training in China. Inadequate outpatient activity has led to changes in trainee work rosters and trainer requirements. Both strengths and deficiencies were confirmed and addressed. Further audit is required.


Assuntos
Internato e Residência , Humanos , Estudos de Tempo e Movimento , Reprodutibilidade dos Testes , Hospitais , Salas Cirúrgicas
11.
Nat Commun ; 15(1): 3587, 2024 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-38678047

RESUMO

The three-dimensional domain structure of ferroelectric materials significantly influences their properties. The ferroelectric domain structure of improper multiferroics, such as YMnO3, is driven by a non-ferroelectric order parameter, leading to unique hexagonal vortex patterns and topologically protected domain walls. Characterizing the three-dimensional structure of these domains and domain walls has been elusive, however, due to a lack of suitable imaging techniques. Here, we present a multi-peak Bragg coherent x-ray diffraction imaging determination of the domain structure in single YMnO3 nanocrystals. We resolve two ferroelectric domains separated by a domain wall and confirm that the primary atomic displacements occur along the crystallographic c-axis. Correlation with atomistic simulations confirms the Mexican hat symmetry model of domain formation, identifying two domains with opposite ferroelectric polarization and adjacent trimerization, manifesting in a clockwise arrangement around the hat's brim.

12.
J Am Soc Nephrol ; 23(3): 525-32, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22193385

RESUMO

Abnormal bone turnover is common in CKD, but its effects on bone quality remain unclear. We qualitatively screened iliac crest bone specimens from patients on dialysis to identify those patients with low (n=18) or high (n=17) bone turnover. In addition, we obtained control bone specimens from 12 healthy volunteers with normal kidney function. In the patient and control specimens, Fourier transform infrared spectroscopy and nanoindentation quantified the material and mechanical properties of the specimens, and we used bone histomorphometry to assess parameters of bone microstructure and bone formation and resorption. Compared with high or normal turnover, bone with low turnover had microstructural abnormalities such as lower cancellous bone volume and reduced trabecular thickness. Compared with normal or low turnover, bone with high turnover had material and nanomechanical abnormalities such as reduced mineral to matrix ratio and lower stiffness. These data suggest that turnover-related alterations in bone quality may contribute to the diminished mechanical competence of bone in CKD, albeit through different mechanisms. Therapies tailored specifically to low- or high-turnover bone may treat renal osteodystrophy more effectively.


Assuntos
Osso e Ossos/metabolismo , Distúrbio Mineral e Ósseo na Doença Renal Crônica/etiologia , Distúrbio Mineral e Ósseo na Doença Renal Crônica/metabolismo , Nefropatias/complicações , Índice de Gravidade de Doença , Adulto , Idoso , Fenômenos Biomecânicos , Biópsia , Densidade Óssea , Osso e Ossos/patologia , Estudos de Casos e Controles , Doença Crônica , Feminino , Humanos , Nefropatias/terapia , Pessoa de Meia-Idade , Diálise Renal , Espectroscopia de Infravermelho com Transformada de Fourier
13.
Int Orthop ; 37(12): 2337-43, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23974837

RESUMO

PURPOSE: The Reflection® second-generation uncemented acetabular component was designed to address increased rates of failure observed with the early acetabular designs. However, the reported survivorship of this acetabular component has been conflicting. The aim of this study was to describe the ten to 15-year survivorship and polyethylene wear rate for the uncemented Reflection® acetabular component performed as part of a primary total hip replacement. METHODS: One hundred and four consecutive Reflection® uncemented acetabular components in 97 patients were identified from a prospective arthroplasty database with a minimum of ten years of follow-up. No patient was lost to follow-up. Mean cohort age was 59.1 years. RESULTS: There were 24 revisions of the acetabular component. The all-cause survival rate at ten years was 77.2% [95% confidence interval (CI) 73.9-80.5]. Mean linear wear was 0.20 mm [standard deviation (SD) 0.08] per year and the volumetric wear was 106.2 mm(3) per year. At final follow-up, more than half the patients had osteolysis identified around the femoral component. The mean Oxford Hip Score was 35.6 (SD 9.8) at a mean follow-up of 11.9 years, with six (11.1%) excellent, 26 (48.1%) good, 17 (31.5%) fair and five (9.3%) poor outcomes. Despite the fact that more than a third had a fair or poor outcome, only four (7.4%) were not satisfied with their hip. CONCLUSIONS: Due to the high rate of relatively asymptomatic polyethylene wear and osteolysis associated with this acetabular component, in our department, we now review all surviving patients both clinically and radiographically on an annual basis.


Assuntos
Acetábulo/cirurgia , Artroplastia de Quadril/instrumentação , Prótese de Quadril/efeitos adversos , Osteoartrite do Quadril/cirurgia , Polietileno/efeitos adversos , Desenho de Prótese , Falha de Prótese , Acetábulo/diagnóstico por imagem , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Coortes , Feminino , Seguimentos , Articulação do Quadril/diagnóstico por imagem , Articulação do Quadril/fisiologia , Articulação do Quadril/cirurgia , Humanos , Estimativa de Kaplan-Meier , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Satisfação do Paciente , Estudos Prospectivos , Radiografia , Amplitude de Movimento Articular/fisiologia , Estudos Retrospectivos , Fatores de Tempo , Resultado do Tratamento
14.
Acta Orthop ; 84(5): 453-9, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24032522

RESUMO

BACKGROUND AND PURPOSE: The micro-architecture of bone has been increasingly recognized as an important determinant of bone strength. Successful operative stabilization of fractures depends on bone strength. We evaluated the osseous micro-architecture and strength of the osteoporotic human femoral head. MATERIAL AND METHODS: 6 femoral heads, obtained during arthroplasty surgery for femoral neck fracture, underwent micro-computed tomography (microCT) scanning at 30 µm, and bone volume ratio (BV/TV), trabecular thickness, structural model index, connection density, and degree of anisotropy for volumes of interest throughout the head were derived. A further 15 femoral heads underwent mechanical testing of compressive failure stress of cubes of trabecular bone from different regions of the head. RESULTS: The greatest density and trabecular thickness was found in the central core that extended from the medial calcar to the physeal scar. This region also correlated with the greatest degree of anisotropy and proportion of plate-like trabeculae. In the epiphyseal region, the trabeculae were organized radially from the physeal scar. The weakest area was found at the apex and peripheral areas of the head. The strongest region was at the center of the head. INTERPRETATION: The center of the femoral head contained the strongest trabecular bone, with the thickest, most dense trabeculae. The apical region was weaker. From an anatomical and mechanical point of view, implants that achieve fixation in or below this central core may achieve the most stable fixation during fracture healing.


Assuntos
Artroplastia de Quadril/métodos , Fraturas do Colo Femoral/patologia , Cabeça do Fêmur/patologia , Fraturas por Osteoporose/patologia , Idoso , Idoso de 80 Anos ou mais , Densidade Óssea/fisiologia , Pinos Ortopédicos , Parafusos Ósseos , Feminino , Fraturas do Colo Femoral/fisiopatologia , Cabeça do Fêmur/fisiopatologia , Humanos , Masculino , Pessoa de Meia-Idade , Fraturas por Osteoporose/fisiopatologia , Tomografia Computadorizada por Raios X/métodos
15.
J Mech Behav Biomed Mater ; 142: 105844, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-37054573

RESUMO

Topology Optimization (TO) determines a material distribution within a domain under given conditions and design constraints, and generally generates complex geometries as a result. Complementary to TO, Additive Manufacturing (AM) offers the ability to fabricate complex geometries which may be difficult to manufacture using traditional techniques such as milling. AM has been used in multiple industries including the medical devices area. Hence, TO may be used to create patient-matched devices where the mechanical response is catered to a particular patient. However, during a medical device regulatory 510(k) pathway, demonstrating that worst-cases are known and tested is critical to the review process. Using TO and AM to predict worst-case designs for subsequent performance testing may be challenging and does not appear to have been thoroughly explored. Investigating the effects of TO input parameters when AM is employed may be the first step in determining the feasibility of predicting these worst-cases. In this paper, the effect of selected TO parameters on the resulting mechanical response and geometries of an AM pipe flange structure are investigated. Four different input parameters were chosen in the TO formulation: (1) penalty factor, (2) volume fraction, (3) element size, and (4) density threshold. Topology optimized designs were fabricated using PA2200 polyamide and the mechanical responses (reaction force, stress, and strain) were observed through experiments (universal testing machine and 3D Digital Image Correlation) and in silico environments (finite element analysis). In addition, 3D scanning and mass measurement were performed to inspect the geometric fidelity of the AM structures. A sensitivity analysis is performed to examine the effect of each TO parameters. The sensitivity analysis revealed mechanical responses can have non-monotonic and non-linear relationships between each tested parameter.


Assuntos
Fenômenos Mecânicos , Nylons , Humanos
16.
Addit Manuf ; 67: 103468, 2023 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-36925558

RESUMO

The onset of the 2019 novel coronavirus disease (COVID-19) led to a shortage of personal protective equipment (PPE), medical devices, and other medical supplies causing many stakeholders and the general public alike to turn to additive manufacturing (AM) as a stopgap when normally accessible devices were not available. However, without a method to test these AM constructs, there continued to be a disconnect between AM suppliers and the community's needs. The objective of this study was to characterize the pressure drop and leakage of four different publicly available AM face mask models with two filter material combinations, as well as to investigate the impact of frame modification techniques including the use of foam strips and hot-water face forming to improve fit when the masks are donned on manikin head forms. AM face mask frame designs were downloaded from public repositories during the early stages of the COVID-19 pandemic. AM face masks were fabricated and tested on manikin head forms within a custom chamber containing dry aerosolized NaCl. Pressure drops, particle penetration, and leakage were evaluated for various flow rates and NaCl concentrations. Results indicated that filter material combination and frame modification played a major role in the overall performance of the AM face masks studied. Filter material combinations showed improved performance when high filtration fabric was used, and the cross-sectional area of the fabric was increased. AM frame modifications appeared to improve AM face mask leakage performance by as much as 69.6%.

17.
Ann Biomed Eng ; 51(1): 34-44, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-35902414

RESUMO

In response to the respiratory protection device shortage during the COVID-19 pandemic, the additive manufacturing (AM) community designed and disseminated numerous AM face masks. Questions regarding the effectiveness of AM masks arose because these masks were often designed with limited (if any) functional performance evaluation. In this study, we present a fit evaluation methodology in which AM face masks are virtually donned on a standard digital headform using finite element-based numerical simulations. We then extract contour plots to visualize the contact patches and gaps and quantify the leakage surface area for each mask frame. We also use the methodology to evaluate the effects of adding a foam gasket and variable face mask sizing, and finally propose a series of best practices. Herein, the methodology is focused only on characterizing the fit of AM mask frames and does not considering filter material or overall performance. We found that AM face masks may provide a sufficiently good fit if the sizing is appropriate and if a sealing gasket material is present to fill the gaps between the mask and face. Without these precautions, the rigid nature of AM materials combined with the wide variation in facial morphology likely results in large gaps and insufficient adaptability to varying user conditions which may render the AM face masks ineffective.


Assuntos
COVID-19 , Humanos , COVID-19/prevenção & controle , COVID-19/epidemiologia , SARS-CoV-2 , Pandemias/prevenção & controle , Máscaras
18.
Front Sociol ; 7: 950557, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36569362

RESUMO

Wellbeing has emerged as a central, if not defining, feature of contemporary social life. Yet, despite its global significance spanning the political, social and economic spectrum, there is a remarkable lack of agreement regarding the conceptualization, definition or operationalisation of wellbeing nor any clear evidence of its success as an instrument of policy. This essay explores the contested terrain of wellbeing by examining the concept in relation to emerging politics, complexities and contradictions. More specifically, the essay: (1) briefly describes the historical origins and development of wellbeing; (2) discusses how it has been reconceptualised within the context of neoliberalism; and, (3) outlines a research agenda offering three ways to investigate wellbeing including: (a) as a wicked problem; (b) as part of the process of "wellbeing washing" within state and other institutional structures and policies; and, (c) in relation to alternative futures, which might encourage us to reimagine or jettison the term altogether.

19.
J Orthop Surg Res ; 17(1): 508, 2022 Nov 24.
Artigo em Inglês | MEDLINE | ID: mdl-36434665

RESUMO

BACKGROUND: Knee patient-reported outcome measures (PROMs) are widely used in research in China, but there is limited evidence on the quality of cross-culturally adapted and original Chinese PROMs. We investigated Chinese language knee PROMs to provide evidence for clinicians on their quality and to guide PROM choices. METHOD: A systematic literature search of databases: PUBMED, CINAHL, EMBASE, and CNKI, using adequate search strings and a three-step screen process identified relevant studies. An independent standardized assessment of the selected studies based on the Evaluating the Measurement of Patient-Reported Outcomes (EMPRO) tool was performed. Inter-rater reliability was assessed using intraclass coefficients (ICC). RESULTS: Thirty-three articles corresponding to 23 knee PROMs were evaluated with EMPRO global scores (100) ranging from 11.11 to 55.42. The attributes 'reliability,' 'validity,' and 'cultural and language adaptation' were significantly better evaluated compared to the attributes 'responsiveness,' 'interpretability,' and 'burden' (for all comparisons p < 0.0001). Moderate-to-excellent inter-rater agreement was observed with ICC values ranging from 0.538 to 0.934. CONCLUSION: We identified six PROMs with a minimum acceptable threshold (> 50/100). The osteoarthritis of knee and hip quality of life, the lower extremity function scale, and the Western Ontario Meniscal Evaluation tool ranked highest. Nevertheless, no single PROM had evidence encompassing all EMPRO attributes, necessitating further studies, especially on responsiveness, interpretability, and burden. We identified duplication of effort as shown by repeated translations of the same PROM; this inefficiency could be ameliorated by rapid approval of Chinese language PROMs documented on original PROM developers' platforms.


Assuntos
Idioma , Qualidade de Vida , Humanos , Reprodutibilidade dos Testes , Inquéritos e Questionários , Medidas de Resultados Relatados pelo Paciente
20.
J Mech Behav Biomed Mater ; 125: 104869, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34653900

RESUMO

Lattice structures are used in a multitude of applications from medical to aerospace, and their adoption in these applications has been further enabled by additive manufacturing. Lattice performance is governed by a multitude of variables and estimating this performance may be needed during various phases of the design and validation process. Numerical modeling and constitutive relationships are common methodologies to assess performance, address risks, lower costs, and accelerate time to market for innovative and potentially life altering products. These methods are usually accompanied by engineering rationales to justify the methods appropriateness. However, engineering analyses and numerical models should be validated using experimental data when possible to quantify the accuracy of their predictions under conditions relevant to their planned use. In this work, a set of lattice design parameters are evaluated using numerical modeling and experimental methods under quasi-static tensile, compressive, and shear modalities. Regular body centered cubic (BCC) and stochastic Voronoi Tessellation Method (VTM) lattices are constructed with three different cell lengths (2.5 mm, 4.0 mm, 5.0 mm) and various strut diameter thicknesses (ranging from 0.536 mm-1.3506 mm) while maintaining the lattice's relative density (0.2 and 0.3). Some strut diameters were selected to challenge the AM process limits. Specimens were fabricated in nylon 12 on a laser powder bed fusion system. Optical microscopy showed up to a 28.6% difference between as-designed and fabricated strut diameters. Simulated reaction loads revealed up to a 4.6% difference in BCC lattices within a constant relative density at a 1.4 mm displacement boundary condition while the VTM samples had up to a 19.5% difference. Errors between the experimental and simulated lattice reaction loads were as high as 97.0%. This error magnitude appears to strongly correlate with lattice strut diameter. These results showcase that a computational estimation, even one with reasonable assumptions, may erroneously characterize the performance of these lattice structures, and that these assumptions should be challenged by experimentally evaluating and validating critical quantities of interest.


Assuntos
Microscopia , Nylons
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