Displaying publications 41 - 60 of 611 in total

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  1. Efficient and easible biocatalysts: Strategies for enzyme improvement. A review
    Albayati SH, Nezhad NG, Taki AG, Rahman RNZRA
    Int J Biol Macromol, 2024 Sep;276(Pt 2):133978.
    PMID: 39038570 DOI: 10.1016/j.ijbiomac.2024.133978
    Owing to the environmental friendliness and vast advantages that enzymes offer in the biotechnology and industry fields, biocatalysts are a prolific investigation field. However, the low catalytic activity, stability, and specific selectivity of the enzyme limit the range of the reaction enzymes involved in. A comprehensive understanding of the protein structure and dynamics in terms of molecular details enables us to tackle these limitations effectively and enhance the catalytic activity by enzyme engineering or modifying the supports and solvents. Along with different strategies including computational, enzyme engineering based on DNA recombination, enzyme immobilization, additives, chemical modification, and physicochemical modification approaches can be promising for the wide spread of industrial enzyme usage. This is attributed to the successful application of biocatalysts in industrial and synthetic processes requires a system that exhibits stability, activity, and reusability in a continuous flow process, thereby reducing the production cost. The main goal of this review is to display relevant approaches for improving enzyme characteristics to overcome their industrial application.
    Matched MeSH terms: Protein Engineering/methods
  2. Nanophase hydroxyapatite as a biomaterial in advanced hard tissue engineering: a review
    Zakaria SM, Sharif Zein SH, Othman MR, Yang F, Jansen JA
    Tissue Eng Part B Rev, 2013 Oct;19(5):431-41.
    PMID: 23557483 DOI: 10.1089/ten.TEB.2012.0624
    Hydroxyapatite is a biocompatible material that is extensively used in the replacement and regeneration of bone material. In nature, nanostructured hydroxyapatite is the main component present in hard body tissues. Hence, the state of the art in nanotechnology can be exploited to synthesize nanophase hydroxyapatite that has similar properties with natural hydroxyapatite. Sustainable methods to mass-produce synthetic hydroxyapatite nanoparticles are being developed to meet the increasing demand for these materials and to further develop the progress made in hard tissue regeneration, especially for orthopedic and dental applications. This article reviews the current developments in nanophase hydroxyapatite through various manufacturing techniques and modifications.
    Matched MeSH terms: Tissue Engineering/methods*; Tissue Engineering/trends
  3. Engineering of microscale three-dimensional pancreatic islet models in vitro and their biomedical applications
    Gao B, Wang L, Han S, Pingguan-Murphy B, Zhang X, Xu F
    Crit Rev Biotechnol, 2016 Aug;36(4):619-29.
    PMID: 25669871 DOI: 10.3109/07388551.2014.1002381
    Diabetes now is the most common chronic disease in the world inducing heavy burden for the people's health. Based on this, diabetes research such as islet function has become a hot topic in medical institutes of the world. Today, in medical institutes, the conventional experiment platform in vitro is monolayer cell culture. However, with the development of micro- and nano-technologies, several microengineering methods have been developed to fabricate three-dimensional (3D) islet models in vitro which can better mimic the islet of pancreases in vivo. These in vitro islet models have shown better cell function than monolayer cells, indicating their great potential as better experimental platforms to elucidate islet behaviors under both physiological and pathological conditions, such as the molecular mechanisms of diabetes and clinical islet transplantation. In this review, we present the state-of-the-art advances in the microengineering methods for fabricating microscale islet models in vitro. We hope this will help researchers to better understand the progress in the engineering 3D islet models and their biomedical applications such as drug screening and islet transplantation.
    Matched MeSH terms: Cell Engineering*
  4. Fulltext Heat transfer analysis of MHD thin film flow of an unsteady second grade fluid past a vertical oscillating belt
    Gul T, Islam S, Shah RA, Khan I, Khalid A, Shafie S
    PLoS One, 2014;9(11):e103843.
    PMID: 25383797 DOI: 10.1371/journal.pone.0103843
    This article aims to study the thin film layer flowing on a vertical oscillating belt. The flow is considered to satisfy the constitutive equation of unsteady second grade fluid. The governing equation for velocity and temperature fields with subjected initial and boundary conditions are solved by two analytical techniques namely Adomian Decomposition Method (ADM) and Optimal Homotopy Asymptotic Method (OHAM). The comparisons of ADM and OHAM solutions for velocity and temperature fields are shown numerically and graphically for both the lift and drainage problems. It is found that both these solutions are identical. In order to understand the physical behavior of the embedded parameters such as Stock number, frequency parameter, magnetic parameter, Brinkman number and Prandtl number, the analytical results are plotted graphically and discussed.
    Matched MeSH terms: Chemical Engineering/methods*
  5. Current strategies in multiphasic scaffold design for osteochondral tissue engineering: A review
    Yousefi AM, Hoque ME, Prasad RG, Uth N
    J Biomed Mater Res A, 2015 Jul;103(7):2460-81.
    PMID: 25345589 DOI: 10.1002/jbm.a.35356
    The repair of osteochondral defects requires a tissue engineering approach that aims at mimicking the physiological properties and structure of two different tissues (cartilage and bone) using specifically designed scaffold-cell constructs. Biphasic and triphasic approaches utilize two or three different architectures, materials, or composites to produce a multilayered construct. This article gives an overview of some of the current strategies in multiphasic/gradient-based scaffold architectures and compositions for tissue engineering of osteochondral defects. In addition, the application of finite element analysis (FEA) in scaffold design and simulation of in vitro and in vivo cell growth outcomes has been briefly covered. FEA-based approaches can potentially be coupled with computer-assisted fabrication systems for controlled deposition and additive manufacturing of the simulated patterns. Finally, a summary of the existing challenges associated with the repair of osteochondral defects as well as some recommendations for future directions have been brought up in the concluding section of this article.
    Matched MeSH terms: Tissue Engineering*
  6. Embracing diversity in user needs for affective design
    Khalid HM
    Appl Ergon, 2006 Jul;37(4):409-18.
    PMID: 16764817
    To develop product portfolios and affective design we need to understand the diversity in user needs. The challenge is how to predict what users want and how they will behave. One approach is to understand user emotions and affective needs, and predict successful product design that can match the needs. This paper discusses affect and its link to cognition. To provide a context, several theories are presented. A framework is described that incorporates characteristics of users, tasks, products, and use environment. The goal is to highlight the importance of emotions in enhancing the value of products. This research field, which we call Hedonomics, is new. There are many challenges in developing valid and reliable measurements of affect, which can influence human factors research as well as design.
    Matched MeSH terms: Human Engineering/methods*
  7. Comparison of bioengineered human bone construct from four sources of osteogenic cells
    Ng AM, Saim AB, Tan KK, Tan GH, Mokhtar SA, Rose IM, et al.
    J Orthop Sci, 2005;10(2):192-9.
    PMID: 15815868
    Osteoprogenitor cells have been reported to be present in periosteum, cancellous and cortical bone, and bone marrow; but no attempt to identify the best cell source for bone tissue engineering has yet been reported. In this study, we aimed to investigate the growth and differentiation pattern of cells derived from these four sources in terms of cell doubling time and expression of osteoblast-specific markers in both monolayer cells and three-dimensional cell constructs in vitro. In parallel, human plasma derived-fibrin was evaluated for use as biomaterial when forming three-dimensional bone constructs. Our findings showed osteoprogenitor cells derived from periosteum to be most proliferative followed by cortical bone, cancellous bone, and then bone marrow aspirate. Bone-forming activity was observed in constructs formed with cells derived from periosteum, whereas calcium deposition was seen throughout the constructs formed with cells derived from cancellous and cortical bones. Although no mineralization activity was seen in constructs formed with osteoprogenitor cells derived from bone marrow, well-organized lacunae as would appear in the early phase of bone reconstruction were noted. Scanning electron microscopy evaluation showed cell proliferation throughout the fibrin matrix, suggesting the possible application of human fibrin as the bioengineered tissue scaffold at non-load-bearing sites.
    Matched MeSH terms: Tissue Engineering/methods*
  8. A sustainable system of systems approach: a new HFE paradigm
    Thatcher A, Yeow PH
    Ergonomics, 2016;59(2):167-78.
    PMID: 26307437 DOI: 10.1080/00140139.2015.1066876
    Sustainability issues such as natural resource depletion, pollution and poor working conditions have no geographical boundaries in our interconnected world. To address these issues requires a paradigm shift within human factors and ergonomics (HFE), to think beyond a bounded, linear model understanding towards a broader systems framework. For this reason, we introduce a sustainable system of systems model that integrates the current hierarchical conceptualisation of possible interventions (i.e., micro-, meso- and macro-ergonomics) with important concepts from the sustainability literature, including the triple bottom line approach and the notion of time frames. Two practical examples from the HFE literature are presented to illustrate the model. The implications of this paradigm shift for HFE researchers and practitioners are discussed and include the long-term sustainability of the HFE community and comprehensive solutions to problems that consider the emergent issues that arise from this interconnected world.
    Matched MeSH terms: Human Engineering/methods*
  9. Bioactive glass reinforced elastomer composites for skeletal regeneration: A review
    Zeimaran E, Pourshahrestani S, Djordjevic I, Pingguan-Murphy B, Kadri NA, Towler MR
    Mater Sci Eng C Mater Biol Appl, 2015 Aug;53:175-88.
    PMID: 26042705 DOI: 10.1016/j.msec.2015.04.035
    Biodegradable elastomers have clinical applicability due to their biocompatibility, tunable degradation and elasticity. The addition of bioactive glasses to these elastomers can impart mechanical properties sufficient for hard tissue replacement. Hence, a composite with a biodegradable polymer matrix and a bioglass filler can offer a method of augmenting existing tissue. This article reviews the applications of such composites for skeletal augmentation.
    Matched MeSH terms: Tissue Engineering*
  10. Cost effectiveness of ergonomic redesign of electronic motherboard
    Sen RN, Yeow PH
    Appl Ergon, 2003 Sep;34(5):453-63.
    PMID: 12963331
    A case study to illustrate the cost effectiveness of ergonomic redesign of electronic motherboard was presented. The factory was running at a loss due to the high costs of rejects and poor quality and productivity. Subjective assessments and direct observations were made on the factory. Investigation revealed that due to motherboard design errors, the machine had difficulty in placing integrated circuits onto the pads, the operators had much difficulty in manual soldering certain components and much unproductive manual cleaning (MC) was required. Consequently, there were high rejects and occupational health and safety (OHS) problems, such as, boredom and work discomfort. Also, much labour and machine costs were spent on repairs. The motherboard was redesigned to correct the design errors, to allow more components to be machine soldered and to reduce MC. This eliminated rejects, reduced repairs, saved US dollars 581495/year and improved operators' OHS. The customer also saved US dollars 142105/year on loss of business.
    Matched MeSH terms: Human Engineering/economics*
  11. Human clones and God's trust: an Islamic view
    Anees MA
    New Perspect Q, 1994;11(1):23-4.
    PMID: 15739295
    Matched MeSH terms: Genetic Engineering/ethics
  12. Recent advances in tissue engineering scaffolds based on polyurethane and modified polyurethane
    Naureen B, Haseeb ASMA, Basirun WJ, Muhamad F
    Mater Sci Eng C Mater Biol Appl, 2021 Jan;118:111228.
    PMID: 33254956 DOI: 10.1016/j.msec.2020.111228
    Organ repair, regeneration, and transplantation are constantly in demand due to various acute, chronic, congenital, and infectious diseases. Apart from traditional remedies, tissue engineering (TE) is among the most effective methods for the repair of damaged tissues via merging the cells, growth factors, and scaffolds. With regards to TE scaffold fabrication technology, polyurethane (PU), a high-performance medical grade synthetic polymer and bioactive material has gained significant attention. PU possesses exclusive biocompatibility, biodegradability, and modifiable chemical, mechanical and thermal properties, owing to its unique structure-properties relationship. During the past few decades, PU TE scaffold bioactive properties have been incorporated or enhanced with biodegradable, electroactive, surface-functionalised, ayurvedic products, ceramics, glass, growth factors, metals, and natural polymers, resulting in the formation of modified polyurethanes (MPUs). This review focuses on the recent advances of PU/MPU scaffolds, especially on the biomedical applications in soft and hard tissue engineering and regenerative medicine. The scientific issues with regards to the PU/MPU scaffolds, such as biodegradation, electroactivity, surface functionalisation, and incorporation of active moieties are also highlighted along with some suggestions for future work.
    Matched MeSH terms: Tissue Engineering*
  13. The remarkable three-dimensional network structure of bacterial cellulose for tissue engineering applications
    Halib N, Ahmad I, Grassi M, Grassi G
    Int J Pharm, 2019 Jul 20;566:631-640.
    PMID: 31195074 DOI: 10.1016/j.ijpharm.2019.06.017
    Cellulose is a natural homopolymer, composed of β-1,4- anhydro-d-glucopyranose units. Unlike plant cellulose, bacterial cellulose (BC), obtained from species belonging to the genera of Acetobacter, Rhizobium, Agrobacterium, and Sarcina through various cultivation methods and techniques, is produced in its pure form. BC is produced in the form of gel-like, never dry sheet with tremendous mechanical properties. Containing up to 99% of water, BC hydrogel is considered biocompatible thus finding robust applications in the health industry. Moreover, BC three-dimensional structure closely resembles the extracellular matrix (ECM) of living tissue. In this review, we focus on the porous BC morphology particularly suited to host oxygen and nutrients thus providing conducive environment for cell growth and proliferation. The remarkable BC porous morphology makes this biological material a promising templet for the generation of 3D tissue culture and possibly for tissue-engineered scaffolds.
    Matched MeSH terms: Tissue Engineering*
  14. The Role of Engineering Ethics on Concrete Fire Safety
    Yahaghi J, Sorooshian S
    Sci Eng Ethics, 2018 04;24(2):819-820.
    PMID: 28281150 DOI: 10.1007/s11948-017-9892-4
    Matched MeSH terms: Engineering/ethics*
  15. Fulltext Angiogenic and osteogenic potentials of dental stem cells in bone tissue engineering
    Yusof MFH, Zahari W, Hashim SNM, Osman ZF, Chandra H, Kannan TP, et al.
    J Oral Biol Craniofac Res, 2017 10 19;8(1):48-53.
    PMID: 29556464 DOI: 10.1016/j.jobcr.2017.10.003
    Manipulation of dental stem cells (DSCs) using current technologies in tissue engineering unveil promising prospect in regenerative medicine. DSCs have shown to possess angiogenic and osteogenic potential in both in vivo and in vitro. Neural crest derived DSCs can successfully be isolated from various dental tissues, exploiting their intrinsic great differentiation potential. In this article, researcher team intent to review the characteristics of DSCs, with focus on their angiogenic and osteogenic differentiation lineage. Clinical data on DSCs are still lacking to prove their restorative abilities despite extensive contemporary literature, warranting research to further validate their application for bone tissue engineering.
    Matched MeSH terms: Engineering; Tissue Engineering
  16. Occupational ergonomics and related musculoskeletal disorders among dentists: A systematic review
    Soo SY, Ang WS, Chong CH, Tew IM, Yahya NA
    Work, 2023;74(2):469-476.
    PMID: 36278379 DOI: 10.3233/WOR-211094
    BACKGROUND: There is an increasing concern about musculoskeletal disorders (MSD), resulting from occupational health hazards among dentists. Dentists who are susceptible to occupational health hazards could develop cumulative trauma disorders, lead to absenteeism from work, loss of productivity and performance or even long-term disability.

    OBJECTIVE: This study aims to determine the prevalence of musculoskeletal disorders among dentists, explore the risk factors and identify the ergonomic preventive measures for dental professionals.

    METHODS: Articles published between 2008-2020 were searched in scientific databases (MEDLINE, PubMed, Scopus and Cochrane Library). The Critical Appraisal Skills Programme Systematic Review Checklist was used to assess the quality of the studies.

    RESULTS: Eighteen studies were found to be suitable in the final review. Relevant data was extracted and summarized from the included studies. The annual prevalence of musculoskeletal disorders in any body site ranged between 68% and 100%. The most predominant regions for musculoskeletal disorders among dental professionals were identified to be the lower back (29% to 94.6%), shoulder (25% to 92.7%), and neck (26% to 92%). The most frequently reported risk factors of MSDs were the individual characteristic female gender (57.1%), followed by awkward working postures (50%), long working experience (50%) and being dental specialists (42.9%). Several preventive measures were identified as the most effective ways in preventing MSDs, the use of magnification (40%) and regular physical activity (40%).

    CONCLUSIONS: This review reported a high prevalence of musculoskeletal disorders (MSD) among dentists. It critically updates and adds the latest evidence on occupational ergonomics among dentists.

    Matched MeSH terms: Human Engineering/methods
  17. Fundamental properties of smart hydrogels for tissue engineering applications: A review
    Khan MUA, Stojanović GM, Abdullah MFB, Dolatshahi-Pirouz A, Marei HE, Ashammakhi N, et al.
    Int J Biol Macromol, 2024 Jan;254(Pt 3):127882.
    PMID: 37951446 DOI: 10.1016/j.ijbiomac.2023.127882
    Tissue engineering is an advanced and potential biomedical approach to treat patients suffering from lost or failed an organ or tissue to repair and regenerate damaged tissues that increase life expectancy. The biopolymers have been used to fabricate smart hydrogels to repair damaged tissue as they imitate the extracellular matrix (ECM) with intricate structural and functional characteristics. These hydrogels offer desired and controllable qualities, such as tunable mechanical stiffness and strength, inherent adaptability and biocompatibility, swellability, and biodegradability, all crucial for tissue engineering. Smart hydrogels provide a superior cellular environment for tissue engineering, enabling the generation of cutting-edge synthetic tissues due to their special qualities, such as stimuli sensitivity and reactivity. Numerous review articles have presented the exceptional potential of hydrogels for various biomedical applications, including drug delivery, regenerative medicine, and tissue engineering. Still, it is essential to write a comprehensive review article on smart hydrogels that successfully addresses the essential challenging issues in tissue engineering. Hence, the recent development on smart hydrogel for state-of-the-art tissue engineering conferred progress, highlighting significant challenges and future perspectives. This review discusses recent advances in smart hydrogels fabricated from biological macromolecules and their use for advanced tissue engineering. It also provides critical insight, emphasizing future research directions and progress in tissue engineering.
    Matched MeSH terms: Tissue Engineering*
  18. Fulltext Status of Plant Protein-Based Green Scaffolds for Regenerative Medicine Applications
    Jahangirian H, Azizi S, Rafiee-Moghaddam R, Baratvand B, Webster TJ
    Biomolecules, 2019 10 17;9(10).
    PMID: 31627453 DOI: 10.3390/biom9100619
    In recent decades, regenerative medicine has merited substantial attention from scientific and research communities. One of the essential requirements for this new strategy in medicine is the production of biocompatible and biodegradable scaffolds with desirable geometric structures and mechanical properties. Despite such promise, it appears that regenerative medicine is the last field to embrace green, or environmentally-friendly, processes, as many traditional tissue engineering materials employ toxic solvents and polymers that are clearly not environmentally friendly. Scaffolds fabricated from plant proteins (for example, zein, soy protein, and wheat gluten), possess proper mechanical properties, remarkable biocompatibility and aqueous stability which make them appropriate green biomaterials for regenerative medicine applications. The use of plant-derived proteins in regenerative medicine has been especially inspired by green medicine, which is the use of environmentally friendly materials in medicine. In the current review paper, the literature is reviewed and summarized for the applicability of plant proteins as biopolymer materials for several green regenerative medicine and tissue engineering applications.
    Matched MeSH terms: Tissue Engineering*
  19. Gene therapy in dentistry: tool of genetic engineering. Revisited
    Gupta K, Singh S, Garg KN
    Arch Oral Biol, 2015 Mar;60(3):439-46.
    PMID: 25540850 DOI: 10.1016/j.archoralbio.2014.11.018
    Advances in biotechnology have brought gene therapy to the forefront of medical research. The concept of transferring genes to tissues for clinical applications has been discussed nearly half a century, but the ability to manipulate genetic material via recombinant DNA technology has brought this goal to reality. The feasibility of gene transfer was first demonstrated using tumour viruses. This led to development of viral and nonviral methods for the genetic modification of somatic cells. Applications of gene therapy to dental and oral problems illustrate the potential impact of this technology on dentistry. Preclinical trial results regarding the same have been very promising. In this review we will discuss methods, vectors involved, clinical implication in dentistry and scientific issues associated with gene therapy.
    Matched MeSH terms: Genetic Engineering
  20. Laser damage helps the eavesdropper in quantum cryptography
    Bugge AN, Sauge S, Ghazali AM, Skaar J, Lydersen L, Makarov V
    Phys Rev Lett, 2014 Feb 21;112(7):070503.
    PMID: 24579579
    We propose a class of attacks on quantum key distribution (QKD) systems where an eavesdropper actively engineers new loopholes by using damaging laser illumination to permanently change properties of system components. This can turn a perfect QKD system into a completely insecure system. A proof-of-principle experiment performed on an avalanche photodiode-based detector shows that laser damage can be used to create loopholes. After ∼1  W illumination, the detectors' dark count rate reduces 2-5 times, permanently improving single-photon counting performance. After ∼1.5  W, the detectors switch permanently into the linear photodetection mode and become completely insecure for QKD applications.
    Matched MeSH terms: Engineering
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