LIVIVO - The Search Portal for Life Sciences

zur deutschen Oberfläche wechseln
Advanced search

Search results

Result 1 - 10 of total 17

Search options

  1. Article ; Online: Mechanical performance of additively manufactured cobalt-chromium-molybdenum auxetic meta-biomaterial bone scaffolds.

    Wanniarachchi, Chameekara T / Arjunan, Arun / Baroutaji, Ahmad / Singh, Manpreet

    Journal of the mechanical behavior of biomedical materials

    2022  Volume 134, Page(s) 105409

    Abstract: Auxetic meta-biomaterials offer unconventional strain behaviour owing to their negative Poisson's ratio (-υ) leading to deformation modes and mechanical properties different to traditional cellular biomaterials. This can lead to favourable outcomes for ... ...

    Abstract Auxetic meta-biomaterials offer unconventional strain behaviour owing to their negative Poisson's ratio (-υ) leading to deformation modes and mechanical properties different to traditional cellular biomaterials. This can lead to favourable outcomes for load-bearing tissue engineering constructs such as bone scaffolds. Emerging early-stage studies have shown the potential of auxetic architecture in increasing cell proliferation and tissue reintegration owing to their -υ. However, research on the development of CoCrMo auxetic meta-biomaterials including bone scaffolds or implants is yet to be reported. In this regard, this paper proposes a potential framework for the development of auxetic meta-biomaterials that can be printed on demand while featuring porosity requirements suitable for load-bearing bone scaffolds. Overall, the performance of five CoCrMo auxetic meta-biomaterial scaffolds characterised under two scenarios for their potential to offer near-zero and high negative Poisson's ratio is demonstrated. Ashby's criterion followed by prototype testing was employed to evaluate the mechanical performance and failure modes of the auxetic meta-biomaterial scaffolds under uniaxial compression. The best performing scaffold architectures are identified through a multi-criteria decision-making procedure combining 'analytic hierarchy process' (AHP) and 'technique for order of preference by similarity to ideal solution' (TOPSIS). The results found the Poisson's ratio for the meta-biomaterial architectures to be in the range of -0.1 to -0.24 at a porosity range of 73-82%. It was found that the meta-biomaterial scaffold (AX1) that offered the highest auxeticity also showed the highest elastic modulus, yield, and ultimate strength of 1.66 GPa, 56 MPa and 158 MPa, respectively. The study demonstrates that the elastic modulus, yield stress, and Poisson's ratio of auxetic meta-biomaterials are primarily influenced by the underlying meta-cellular architecture followed by relative density offering a secondary influence.
    MeSH term(s) Biocompatible Materials ; Chromium ; Cobalt ; Molybdenum ; Porosity
    Chemical Substances Biocompatible Materials ; Chromium (0R0008Q3JB) ; Cobalt (3G0H8C9362) ; Molybdenum (81AH48963U)
    Language English
    Publishing date 2022-08-12
    Publishing country Netherlands
    Document type Journal Article
    ZDB-ID 2378381-3
    ISSN 1878-0180 ; 1751-6161
    ISSN (online) 1878-0180
    ISSN 1751-6161
    DOI 10.1016/j.jmbbm.2022.105409
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  2. Article ; Online: Extra low interstitial titanium based fully porous morphological bone scaffolds manufactured using selective laser melting.

    Bari, Klaudio / Arjunan, Arun

    Journal of the mechanical behavior of biomedical materials

    2019  Volume 95, Page(s) 1–12

    Abstract: Lattice structure based morphologically matched scaffolds is rapidly growing facilitated by developments in Additive Manufacturing. These porous structures are particularly promising due to their potential in reducing stress shielding and maladapted ... ...

    Abstract Lattice structure based morphologically matched scaffolds is rapidly growing facilitated by developments in Additive Manufacturing. These porous structures are particularly promising due to their potential in reducing stress shielding and maladapted stress concentration. Accordingly, this study presents Extra Low Interstitial (ELI) Titanium alloy based morphological scaffolds featuring three different porous architecture. All scaffolds were additively manufactured using Selective Laser Melting from Ti6Al4V ELI with porosities of 73.85, 60.53 and 55.26% with the global geometry dictated through X-Ray Computed Tomography. The elastic and plastic performance of both the scaffold prototypes and the bone section being replaced were evaluated through uniaxial compression testing. Comparing the data, the suitability of the Maxwell criterion in evaluating the stiffness behaviour of fully porous morphological scaffolds are carried out. The outcomes show that the best performing scaffolds presented in this study have high strength (169 MPa) and low stiffness (5.09 GPa) suitable to minimise stress shielding. The matching morphology in addition to high porosity allow adequate space for flow circulation and has the potential to reduce maladapted stress concentration. Finally, the Electron Diffraction X-ray analysis revealed a small difference in the composition of aluminium between the particle and the bonding material at the scaffold surface.
    MeSH term(s) Compressive Strength ; Lasers ; Materials Testing ; Phase Transition ; Porosity ; Tibia/cytology ; Tibia/diagnostic imaging ; Tibia/drug effects ; Tissue Scaffolds/chemistry ; Titanium/chemistry ; Titanium/pharmacology ; X-Ray Microtomography
    Chemical Substances titanium alloy (TiAl6V4) (12743-70-3) ; Titanium (D1JT611TNE)
    Language English
    Publishing date 2019-03-28
    Publishing country Netherlands
    Document type Journal Article
    ZDB-ID 2378381-3
    ISSN 1878-0180 ; 1751-6161
    ISSN (online) 1878-0180
    ISSN 1751-6161
    DOI 10.1016/j.jmbbm.2019.03.025
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  3. Article ; Online: 3D printed auxetic nasopharyngeal swabs for COVID-19 sample collection.

    Arjunan, Arun / Zahid, Suhaib / Baroutaji, Ahmad / Robinson, John

    Journal of the mechanical behavior of biomedical materials

    2020  Volume 114, Page(s) 104175

    Abstract: The COVID-19 pandemic has resulted in worldwide shortages of nasopharyngeal swabs required for sample collection. While the shortages are becoming acute due to supply chain disruptions, the demand for testing has increased both as a prerequisite to ... ...

    Abstract The COVID-19 pandemic has resulted in worldwide shortages of nasopharyngeal swabs required for sample collection. While the shortages are becoming acute due to supply chain disruptions, the demand for testing has increased both as a prerequisite to lifting restrictions and in preparation for the second wave. One of the potential solutions to this crisis is the development of 3D printed nasopharyngeal swabs that behave like traditional swabs. However, the opportunity to digitally conceive and fabricate swabs allows for design improvements that can potentially reduce patient pain and discomfort. The study reports the progress that has been made on the development of auxetic nasopharyngeal swabs that can shrink under axial resistance. This allows the swab to navigate through the nasal cavity with significantly less stress on the surrounding tissues. This is achieved through systematically conceived negative Poisson's ratio (-υ) structures in a biocompatible material. Finite element (FE) and surrogate modelling techniques were employed to identify the most optimal swab shape that allows for the highest negative strain (-ε
    MeSH term(s) COVID-19/diagnosis ; COVID-19 Testing/instrumentation ; Equipment Design ; Mechanical Phenomena ; Nasopharynx/virology ; Printing, Three-Dimensional ; Specimen Handling/instrumentation
    Keywords covid19
    Language English
    Publishing date 2020-11-12
    Publishing country Netherlands
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2378381-3
    ISSN 1878-0180 ; 1751-6161
    ISSN (online) 1878-0180
    ISSN 1751-6161
    DOI 10.1016/j.jmbbm.2020.104175
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  4. Article ; Online: ASO Author Reflections: Extraskeletal Ewing Sarcoma-Outcomes and Prognosticators of a Rare Malignancy.

    Mathew, Joseph / Arjunan, Ravi / Dasappa, Ashwathappa / Namachivayam, ArunKumar

    Annals of surgical oncology

    2023  Volume 30, Issue 5, Page(s) 3095–3096

    MeSH term(s) Humans ; Sarcoma, Ewing/pathology ; Soft Tissue Neoplasms
    Language English
    Publishing date 2023-01-25
    Publishing country United States
    Document type Journal Article ; Comment
    ZDB-ID 1200469-8
    ISSN 1534-4681 ; 1068-9265
    ISSN (online) 1534-4681
    ISSN 1068-9265
    DOI 10.1245/s10434-023-13134-x
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  5. Article: 3D printed auxetic nasopharyngeal swabs for COVID-19 sample collection

    Arjunan, Arun Zahid Suhaib Baroutaji Ahmad Robinson John

    Journal of the Mechanical Behavior of Biomedical Materials

    Abstract: The COVID-19 pandemic has resulted in worldwide shortages of nasopharyngeal swabs required for sample collection While the shortages are becoming acute due to supply chain disruptions, the demand for testing has increased both as a prerequisite to ... ...

    Abstract The COVID-19 pandemic has resulted in worldwide shortages of nasopharyngeal swabs required for sample collection While the shortages are becoming acute due to supply chain disruptions, the demand for testing has increased both as a prerequisite to lifting restrictions and in preparation for the second wave One of the potential solutions to this crisis is the development of 3D printed nasopharyngeal swabs that behave like traditional swabs However, the opportunity to digitally conceive and fabricate swabs allows for design improvements that can potentially reduce patient pain and discomfort The study reports the progress that has been made on the development of auxetic nasopharyngeal swabs that can shrink under axial resistance This allows the swab to navigate through the nasal cavity with significantly less stress on the surrounding tissues This is achieved through systematically conceived negative Poisson's ratio (−υ) structures in a biocompatible material Finite element (FE) and surrogate modelling techniques were employed to identify the most optimal swab shape that allows for the highest negative strain (−εlat) under safe stress (σvon) The influence and interaction effects of the geometrical parameters on the swab's performance were also characterised The research demonstrates a new viewpoint for the development of functional nasopharyngeal swabs that can be 3D printed to reduce patient discomfort The methodology can be further exploited to address various challenges in biomedical devices and redistributed manufacturing
    Keywords covid19
    Publisher WHO
    Document type Article
    Note WHO #Covidence: #919607
    Database COVID19

    Kategorien

  6. Article ; Online: Mechanical performance of highly permeable laser melted Ti6Al4V bone scaffolds.

    Arjunan, Arun / Demetriou, Marios / Baroutaji, Ahmad / Wang, Chang

    Journal of the mechanical behavior of biomedical materials

    2019  Volume 102, Page(s) 103517

    Abstract: Critically engineered stiffness and strength of a scaffold are crucial for managing maladapted stress concentration and reducing stress shielding. At the same time, suitable porosity and permeability are key to facilitate biological activities associated ...

    Abstract Critically engineered stiffness and strength of a scaffold are crucial for managing maladapted stress concentration and reducing stress shielding. At the same time, suitable porosity and permeability are key to facilitate biological activities associated with bone growth and nutrient delivery. A systematic balance of all these parameters are required for the development of an effective bone scaffold. Traditionally, the approach has been to study each of these parameters in isolation without considering their interdependence to achieve specific properties at a certain porosity. The purpose of this study is to undertake a holistic investigation considering the stiffness, strength, permeability, and stress concentration of six scaffold architectures featuring a 68.46-90.98% porosity. With an initial target of a tibial host segment, the permeability was characterised using Computational Fluid Dynamics (CFD) in conjunction with Darcy's law. Following this, Ashby's criterion, experimental tests, and Finite Element Method (FEM) were employed to study the mechanical behaviour and their interdependencies under uniaxial compression. The FE model was validated and further extended to study the influence of stress concentration on both the stiffness and strength of the scaffolds. The results showed that the pore shape can influence permeability, stiffness, strength, and the stress concentration factor of Ti6Al4V bone scaffolds. Furthermore, the numerical results demonstrate the effect to which structural performance of highly porous scaffolds deviate, as a result of the Selective Laser Melting (SLM) process. In addition, the study demonstrates that stiffness and strength of bone scaffold at a targeted porosity is linked to the pore shape and the associated stress concentration allowing to exploit the design freedom associated with SLM.
    MeSH term(s) Alloys ; Lasers ; Porosity ; Stress, Mechanical ; Tissue Scaffolds ; Titanium
    Chemical Substances Alloys ; titanium alloy (TiAl6V4) (12743-70-3) ; Titanium (D1JT611TNE)
    Language English
    Publishing date 2019-11-06
    Publishing country Netherlands
    Document type Journal Article
    ZDB-ID 2378381-3
    ISSN 1878-0180 ; 1751-6161
    ISSN (online) 1878-0180
    ISSN 1751-6161
    DOI 10.1016/j.jmbbm.2019.103517
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  7. Article ; Online: 3D printed auxetic nasopharyngeal swabs for COVID-19 sample collection

    Arjunan, Arun / Zahid, Suhaib / Baroutaji, Ahmad / Robinson, John

    Journal of the Mechanical Behavior of Biomedical Materials

    2020  , Page(s) 104175

    Keywords Mechanics of Materials ; Biomaterials ; Biomedical Engineering ; covid19
    Language English
    Publisher Elsevier BV
    Publishing country us
    Document type Article ; Online
    ZDB-ID 2378381-3
    ISSN 1878-0180 ; 1751-6161
    ISSN (online) 1878-0180
    ISSN 1751-6161
    DOI 10.1016/j.jmbbm.2020.104175
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

    More links

    Kategorien

  8. Article ; Online: 3D Printed Cobalt-Chromium-Molybdenum Porous Superalloy with Superior Antiviral Activity.

    Arjunan, Arun / Robinson, John / Baroutaji, Ahmad / Tuñón-Molina, Alberto / Martí, Miguel / Serrano-Aroca, Ángel

    International journal of molecular sciences

    2021  Volume 22, Issue 23

    Abstract: COVID-19 pandemic and associated supply-chain disruptions emphasise the requirement for antimicrobial materials for on-demand manufacturing. Besides aerosol transmission, SARS-CoV-2 is also propagated through contact with virus-contaminated surfaces. As ... ...

    Abstract COVID-19 pandemic and associated supply-chain disruptions emphasise the requirement for antimicrobial materials for on-demand manufacturing. Besides aerosol transmission, SARS-CoV-2 is also propagated through contact with virus-contaminated surfaces. As such, the development of effective biofunctional materials that can inactivate SARS-CoV-2 is critical for pandemic preparedness. Such materials will enable the rational development of antiviral devices with prolonged serviceability, reducing the environmental burden of disposable alternatives. This research reveals the novel use of Laser Powder Bed Fusion (LPBF) to 3D print porous Cobalt-Chromium-Molybdenum (Co-Cr-Mo) superalloy with potent antiviral activity (100% viral inactivation in 30 min). The porous material was rationally conceived using a multi-objective surrogate model featuring track thickness (tt) and pore diameter (ϕd) as responses. The regression analysis found the most significant parameters for Co-Cr-Mo track formation to be the interaction effects of scanning rate (Vs) and laser power (Pl) in the order PlVs>Vs>Pl. Contrastively, the pore diameter was found to be primarily driven by the hatch spacing (Sh). The study is the first to demonstrate the superior antiviral properties of 3D printed Co-Cr-Mo superalloy against an enveloped virus used as biosafe viral model of SARS-CoV-2. The material significantly outperforms the viral inactivation time of other broadly used antiviral metals such as copper and silver, as the material's viral inactivation time was from 5 h to 30 min. As such, the study goes beyond the current state-of-the-art in antiviral alloys to provide extra protection to combat the SARS-CoV-2 viral spread. The evolving nature of the COVID-19 pandemic brings new and unpredictable challenges where on-demand 3D printing of antiviral materials can achieve rapid solutions while reducing the environmental impact of disposable devices.
    MeSH term(s) Alloys ; Antiviral Agents/pharmacology ; COVID-19 ; Chromium/pharmacology ; Cobalt/pharmacology ; Humans ; Molybdenum/pharmacology ; Porosity ; Printing, Three-Dimensional ; SARS-CoV-2/drug effects ; Surface Properties ; Virus Inactivation/drug effects
    Chemical Substances Alloys ; Antiviral Agents ; Chromium (0R0008Q3JB) ; Cobalt (3G0H8C9362) ; Molybdenum (81AH48963U)
    Language English
    Publishing date 2021-11-24
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2019364-6
    ISSN 1422-0067 ; 1422-0067 ; 1661-6596
    ISSN (online) 1422-0067
    ISSN 1422-0067 ; 1661-6596
    DOI 10.3390/ijms222312721
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  9. Article: Electrical Conductivity of Additively Manufactured Copper and Silver for Electrical Winding Applications.

    Robinson, John / Munagala, Sai Priya / Arjunan, Arun / Simpson, Nick / Jones, Ryan / Baroutaji, Ahmad / Govindaraman, Loganathan T / Lyall, Iain

    Materials (Basel, Switzerland)

    2022  Volume 15, Issue 21

    Abstract: Efficient and power-dense electrical machines are critical in driving the next generation of green energy technologies for many industries including automotive, aerospace and energy. However, one of the primary requirements to enable this is the ... ...

    Abstract Efficient and power-dense electrical machines are critical in driving the next generation of green energy technologies for many industries including automotive, aerospace and energy. However, one of the primary requirements to enable this is the fabrication of compact custom windings with optimised materials and geometries. Electrical machine windings rely on highly electrically conductive materials, and therefore, the Additive Manufacturing (AM) of custom copper (Cu) and silver (Ag) windings offers opportunities to simultaneously improve efficiency through optimised materials, custom geometries and topology and thermal management through integrated cooling strategies. Laser Powder Bed Fusion (L-PBF) is the most mature AM technology for metals, however, laser processing highly reflective and conductive metals such as Cu and Ag is highly challenging due to insufficient energy absorption. In this regard, this study details the 400 W L-PBF processing of high-purity Cu, Ag and Cu-Ag alloys and the resultant electrical conductivity performance. Six Cu and Ag material variants are investigated in four comparative studies characterising the influence of material composition, powder recoating, laser exposure and electropolishing. The highest density and electrical conductivity achieved was 88% and 73% IACS, respectively. To aid in the application of electrical insulation coatings, electropolishing parameters are established to improve surface roughness. Finally, proof-of-concept electrical machine coils are fabricated, highlighting the potential for 400 W L-PBF processing of Cu and Ag, extending the current state of the art.
    Language English
    Publishing date 2022-10-28
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2487261-1
    ISSN 1996-1944
    ISSN 1996-1944
    DOI 10.3390/ma15217563
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  10. Article ; Online: Prognostic Factors and Clinical Outcomes in Extraskeletal Ewing Sarcoma: A Cohort Study.

    Mathew, Joseph / Arjunan, Ravi / Dasappa, Ashwathappa / Namachivayam, ArunKumar

    Annals of surgical oncology

    2022  Volume 30, Issue 5, Page(s) 3084–3094

    Abstract: Background: Extraskeletal Ewing sarcoma (ESE) is a lesser-known, rarer counterpart of Ewing sarcoma of bone. This single-center study sought to evaluate the prognosticators and outcomes following multimodality therapy in patients with ESE.: Methods: ... ...

    Abstract Background: Extraskeletal Ewing sarcoma (ESE) is a lesser-known, rarer counterpart of Ewing sarcoma of bone. This single-center study sought to evaluate the prognosticators and outcomes following multimodality therapy in patients with ESE.
    Methods: Forty-seven patients with ESE, treated between 2013 and 2018 with a standardized protocol and multimodality therapy using established doxorubicin-based regimens, were followed-up to assess outcomes.
    Results: Median age at diagnosis was 20 (range 7-56) years, and 57.4% were male. Median tumor size was 7 (range 2-21) cm. The symptom-duration ranged from 1 to 8 (median 4) months. Tumor-site was trunkal in 61.7%, extremity in 23.4%, and head and neck 14.9%. Of the 35 patients with nonmetastatic disease at presentation, 13 underwent upfront surgery. The rest received chemotherapy followed by local treatment, which was surgical in 15 and radiotherapy in 5. At median follow-up of 24 (range 5-98) months, 55.3% patients had experienced events, and 29.8% had died of progressive disease. Three-year event-free survival was 41.1%, and overall survival was 53%. On univariate analysis, trunkal location, upfront surgery, and positive surgical margins were associated with inferior EFS. Trunkal tumors and upfront surgery were also associated with poorer OS. On multivariate analysis, trunkal location and margin-positive resections retained statistical significance for adverse EFS.
    Conclusions: Unless clearly resectable upfront, ESE should be downstaged with chemotherapy before local treatment. A margin-negative resection should be the objective when performing surgery. Definitive radiotherapy is an alternative in tumors not amenable for complete excision or when anticipated postoperative morbidity precludes radical surgery.
    MeSH term(s) Humans ; Male ; Child ; Adolescent ; Young Adult ; Adult ; Middle Aged ; Female ; Sarcoma, Ewing/therapy ; Sarcoma, Ewing/pathology ; Cohort Studies ; Bone Neoplasms/pathology ; Prognosis ; Treatment Outcome ; Combined Modality Therapy ; Retrospective Studies ; Antineoplastic Combined Chemotherapy Protocols/therapeutic use
    Language English
    Publishing date 2022-12-23
    Publishing country United States
    Document type Journal Article
    ZDB-ID 1200469-8
    ISSN 1534-4681 ; 1068-9265
    ISSN (online) 1534-4681
    ISSN 1068-9265
    DOI 10.1245/s10434-022-12992-1
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

To top