The relevance of lean thinking to sustainable improvement of public office buildings in Nigeria

This study looked into the relevance of lean thinking, particularly the application of muda as a supplement to the sustainable improvement diagnosis technique of existing office buildings, for a fuller assessment of user's requirement in Nigeria. The impact of muda as related to the triple bottom line of sustainable development on perceived job productivity and design features was estimated from end-user's perspective, using diagnostic POE as data acquiring tool while the confirmatory analysis was done through AMOS, SPSS and MS Excel to explain the relationship between the different variables. The findings showed that muda is inherent in public office buildings and it has highly significant causal effects of 0.66 and 0.76, respectively on perceived job productivity and design features; it also has strong effect sizes of 44 and 58% in explaining both their variances, respectively. The result revealed that users require more improvement in facilities as against spatial plan and structures while there is a medium and positive correlation of 0.48 between perceived job productivity and design features implying that the improvement of one will consequently lead to the improvement of the other. The study concludes that lean thinking is relevant to building improvement and could serve as good supplement to the current improvement diagnosis of existing public office buildings but not as a substitute since data were only collected from users who are not able to provide the required technical data that would otherwise warrant use of equipment

Properties of tilapia collagen as a biomaterial for tissue engineering: A review

Collagen is one of the common biopolymers used as a biomaterial in tissue engineering applications due to its biocompatibility and biodegradability properties. Collagen derived from various sources and mostly found in porcine and bovine skin. However, due to religious concerns and the dangers of animal-borne diseases possesses by these mammalian derived collagens, marine collagens are extensively investigated as an alternative to substitute mammalian collagens in tissue engineering applications. Among those marine collagens, tilapia (Oreochromis niloticus) collagens are known to have a great potential to be used as biomaterials for tissue engineering application due to its higher thermal stability compared to other marine sources. Therefore, this study aims to review chemical and biological properties of tilapia collagen as a biomaterial for tissue engineering applications. The contents are mainly focused on the extraction yield, amino acid composition, thermal stability, cross-linking, biocompatibility, biodegradability, immunogenicity and hemostasis of tilapia collagen

Emerging of cardiovascular metal stent: a review on drug-eluting stent towards the utilisation of herbal coating

Metal stents used in the treatment of percutaneous coronary intervention (PCI) have revolutionized in treating atherosclerosis disease. Starting from the emergence of bare metal stent (BMS), this stent has been progressively developed into drug-eluting stent (DES) and biodegradable stent. By focusing on DES, various drugs have been used to coat metal stent with the aims to overcome in-stent restenosis and stent thrombosis. Therefore, the utilisation of various drugs and polymers as coating materials was reviewed in this study to identify possible alternative to overcome the current DES problems. Even though, both complications of BMS are covered successfully by DES, however, DES projects long term complications of delayed endotheliasation, delayed wound healing and late stent thrombosis. Another alternative of herb coating on DES is considered to be a potential approach in improving endotheliasation and retarding smooth muscle cells proliferation to accelerate wound healing and to prevent late stent thrombosis

Electrodeposition of ginseng/polyaniline encapsulated poly(lactic-co-glycolic acid) microcapsule coating on stainless steel 316L at different deposition parameters

Electrodeposition is commonly used to deposit ceramic or metal coating on metallic implants. Its utilization in depositing polymer microcapsule coating is currently being explored. However, there is no encapsulation of drug within polymer microcapsules that will enhance its chemical and biological properties. Therefore, in this study, ginseng which is known for its multiple therapeutic effects was encapsulated inside biodegradable poly(lactic-co-glycolic acid) (PLGA) microcapsules to be coated on pre-treated medical grade stainless steel 316L (SS316L) using an electrodeposition technique. Polyaniline (PANI) was incorporated within the microcapsules to drive the formation of microcapsule coating. The electrodeposition was performed at different current densities (1–3mA) and different deposition times (20–60s). The chemical composition, morphology and wettability of the microcapsule coatings were characterized through attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), scanning electron microscopy (SEM) and contact angle analyses. The changes of electrolyte colors, before and after the electrodeposition were also observed. The addition of PANI has formed low wettability and uniform microcapsule coatings at 2mA current density and 40s deposition time. Reduction in the current density or deposition time caused less attachment of microcapsule coatings with high wettability records. While prolonging either one parameter has led to debris formation and melted microcapsules with non-uniform wettability measurements. The color of electrolytes was also changed from milky white to dark yellow when the current density and deposition time increased. The application of tolerable current density and deposition time is crucial to obtain a uniform microcapsule coating, projecting a controlled release of encapsulated drug

Structure-property relationships of iron-hydroxyapatite ceramic matrix nanocomposite fabricated using mechanosynthesis method

Hydroxyapatite (HAp) is an attractive bioceramics due to its similar composition to bone mineral and its ability to promote bone-implant interaction. However, its low strength has limited its application as load bearing implants. This paper presented a work focusing on the improvement of HAp mechanical property by synthesizing iron (Fe)-reinforced bovine HAp nanocomposite powders via mechanosynthesis method. The synthesis process was performed using high energy milling at varied milling time (3, 6, 9, and 12 h). The samples were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), and scanning electron microscopy (SEM). Its mechanical properties were investigated by micro-Vicker's hardness and compression tests. Results showed that milling time directly influenced the characteristics of the nanocomposite powders. Amorphous BHAp was formed after 9 and 12 h milling in the presence of HPO4 2 - ions. Continuous milling has improved the crystallinity of Fe without changing the HAp lattice structure. The nanocomposite powders were found in spherical shape, agglomerated and dense after longer milling time. The hardness and Young's modulus of the nanocomposites were also increased at 69% and 66%, respectively, as the milling time was prolonged from 3 to 12 h. Therefore, the improvement of the mechanical properties of nanocomposite was attributed to high Fe crystallinity and homogenous, dense structure produced by mechanosynthesi

Stingless bee honey incorporated cellulose hydrogel/poly(lactic-co-glycolic acid) patch as an alternative treatment for aphthous stomatitis

Aphthous stomatitis is a disease that often reappears, causing irritation and pain. Common topical medications to treat aphthous stomatitis are fast-dissolving synthetic drugs, sometimes with limited therapeutic effectiveness. In this study, a patch, composed of a stingless bee honey incorporated cellulose hydrogel layer and a poly(lactic-co-glycolic acid) (PLGA) layer, was fabricated as an alternative treatment for aphthous stomatitis. The composition of the honey patches was verified by the presence of a distinct physical structure, considerable wettability records and lower degradation percentages on the layers containing higher PLGA concentrations. The honey patches were capable to retard Eschericia coli in the early hours (0.5-2 hours) and Staphylococcus aureus in the late hours (2-4 hours) of application, with tolerable cell viability and cell closure. The therapeutic values of the honey patches in retarding bacterial growth and inducing cell closure recommend the developed patches to be used in aphthous stomatitis treatment

A Systematic Analysis of Additive Manufacturing Techniques in the Bioengineering of In Vitro Cardiovascular Models

Additive Manufacturing is noted for ease of product customization and short production run cost-effectiveness. As our global population approaches 8 billion, additive manufacturing has a future in maintaining and improving average human life expectancy for the same reasons that it has advantaged general manufacturing. In recent years, additive manufacturing has been applied to tissue engineering, regenerative medicine, and drug delivery. Additive Manufacturing combined with tissue engineering and biocompatibility studies offers future opportunities for various complex cardiovascular implants and surgeries. This paper is a comprehensive overview of current technological advancements in additive manufacturing with potential for cardiovascular application. The current limitations and prospects of the technology for cardiovascular applications are explored and evaluated

Synthesis and characterization of collagen-hydroxyapatite immobilized on polydopamine grafted stainless steel

Hydroxyapatite (HA) and collagen have been coated on metallic implants to accelerate osseointegration. Most methods to coat HA require high sintering temperature, high cost and high energy power while the methods to coat collagen commonly produce unstable coating. Therefore, in this study, a polydopamine film was used as an intermediate layer to immobilize HA and collagen type I on a medical grade stainless steel (SS316L) implant to overcome those disadvantages. The SS316L disks were pre-treated and grafted with a polydopamine film. It was then covalently immobilized with collagen fibers at different immersion times (6, 12 and 24. h). The disks were further biomineralized with HA in simulated body fluid (SBF) for 7. days. The film surfaces were characterized by FTIR, FESEM-EDX, XRD and contact angle analyses to investigate the chemical composition, morphology, crystallinity and wettability properties. The collagen and carbonated HA (lath-like surface) were successfully immobilized on the polydopamine film with less agglomeration as the immersion time in the collagen solution increased. Increasing the immersion time accelerated the activation of carboxylic groups in the collagen to form an amide cross-linkage for heterogenous nucleation of HA. Furthermore, the crystallinity and wettability properties were also enhanced with the closest theoretical Ca/P ratio. As a conclusion, the immobilization of collagen at 24. h has produced better HA formation and wettability property that might be beneficial for the attachment and proliferation of osteoblast cells on biomedical implants

Antibacterial Effect of Ginseng/polyaniline Encapsulated in Poly(Lactic-co-glycolic Acid) Microcapsules Coating on Stainless Steel 316L

Implant infection is one the current complications of implant restoration. Incorporation of a material that possesses antibacterial property is crucial in combating implant infection. In this study, polyaniline (PANI) is incorporated in ginseng encapsulated poly (lactic-co-glycolic acid) (PLGA) microcapsules to equip the microcapsules with an antibacterial effect. The microcapsules are intended for drug delivery purpose as the ginseng is comprised of abundant therapeutic values and the PLGA is known for its degradation property. The microcapsules were coated on stainless steel 316L using an electro-deposition technique. The chemical composition, morphology and antibacterial activity of the samples were analyzed through ATR-FTIR, SEM and bacterial count test. A greater volume of microcapsules was coated on the stainless steel 316L with the addition of PANI through the appearance of intense ginseng (O–H and C=C bands) and PLGA (C=O) peaks on the ATR-FTIR spectra and through the visualization of spherical morphology of microcapsules on the pre-treated metal. The incorporation of PANI also has induced the antibacterial efficacy of the microcapsules to 87.64%. Therefore, PANI has served as an antibacterial agent that could be useful in the development of implant coating materials while driving the formation of ginseng encapsulated PLGA microcapsules