The effects of decellularisation on the mechanical properties of bone, and subsequent recellularisation of the samples.

Regenerative medicine strategies involving decellularised extracellular matrix scaffolds are developing fast and, in particular, decellularized bone has been proposed for bone tissue engineering. This study aimed to establish decellularisation and recellularisation protocols and to measure the Young’s modulus and pore size of the decellularised trabecular bone samples. Twelve bovine cancellous proximal femur samples (7mm x 7mm x 2mm) were decellularised by six cycles of overnight incubation at 37°C using two protocols: A – 10mM Tris, 1mM EDTA, 0.1% v/v Triton X-100 and B – method A plus 0.5% w/v trypsin. Decellularisation was confirmed by the absence of DNA staining with DAPI both by detecting any DNA remaining on the bone matrix spectrofluorometrically, and by microscopic examination. Young's modulus was determined before and after incubation through compression testing at 1 mm/s up to 400N (8.16MPa). The porosity of the bone samples before and after decellularisation was measured using a mercury porosimeter. Recellularisation using HOS cells (seeded at 5x105 cells per cm2bone) progressed for up to 3 weeks in DMEM supplemented with L-ascorbic acid, β-glycerophosphate, dexamethasone, FCS, PEST, and NEAA. Bone samples were placed onto non-adherent dishes and adherent dishes. The extent of recellularisation was compared in static and dynamic culture conditions using a roller incubator set at 15 rpm to effect dynamic conditions. DAPI staining revealed that protocol B removed all measurable DNA from the bone samples (Figure 1). Decellularisation did not affect Young’s modulus (Figure 2). Pore diameters did not differ with decellularisation and were in the ideal range for cell growth. Mean ALP activity (Figure 3A) and MTT reduction (Figure 3C) was greater on the adherent surface than on non-adherent surface albeit non-significantly. There was no significant difference between static and dynamic conditions in ALP activities between 3 and 7 days (Figure 3B). Data suggests that cells proliferated more readily when samples were placed in adherent dishes (Figure 3D). This work has established appropriate protocols to make donor bone scaffolds with appropriate porosity to allow reseeding with human bone cells.These could be used to repair bone defects in recipient patients

Physical Performance and Cross Layer Design for Wireless Mesh Networks

Wireless mesh networks (WMNs) are an alternative technology for last-mile broadband Internet access that can support broadband services. However, for a WMN to be all it can be, considerable research efforts are still needed. In WMNs, the Orthogonal Frequency Division Multiplexing (OFDM) system is chose to provide the better performance at the physical layer design. OFDM is very tolerant to ISI and it's spectrally efficient. OFDM also very susceptible to phase and frequency offsets. This paper presents the physical layer design of an OFDM system for wireless mesh networkin

Empowering women-owned businesses in the era of digital transformation: a review of the opportunities and challenges

This paper aimed to discuss the opportunity and challenges that are faced by women entrepreneurs in the current digital transformation development. A summary of scholarly works alongside the discussion of some important findings based on the centred issue was presented in the current paper. The analysis was focused on explaining the role of the most important digital business solution, namely social media. The major challenges of pursuing digital alternative were also discussed, varying from a traditional gender issue to emerging digital pressures. This paper provides the relevant academic explanation of the underlying requirements for creating successful women entrepreneurs in digital business, while the highlighted pitfalls can help them avoid incidentally occurrence of business failures

Environmental Analysis Of Quasi-Static Electric Field Changes Of Tropical Lightning Flashes

The environmental conditions leading to the bouncing-wave discharge and the subsequent electron beam remain to be investigated in more detailed future studies. The analysis of quasi-static initial electric field changes (IECs) were found at the beginning of all 24 lightning flashes detected within reversal distance (22 Negative Cloud-to-Ground (–CG) and 2 normal Intra-Cloud (IC) flashes) in a tropical storm on June 15th, 2017 close to our station in Malacca, Malaysia (2.314077° N, 102.318282° E). The IECs durations averaged 4.28 ms for –CG flashes (range 1.48 to 9.45 ms) and averaged 11.30 ms for normal ICs flashes (range 7.24 to 15.35 ms). In comparison to Florida storms, the duration of IECs for –CG and IC flashes were 0.18 ms (range 0.08 to 0.33 ms) and 1.53 ms (range 0.18 to 5.70 ms), respectively. Moreover, the magnitudes of E-change for tropical thunderstorm were 0.13 V/m (range 0.03 to 0.44 V/m) for –CG flashes and-0.20 V/m (range-0.13 to-0.27 V/m) for IC flashes. The E-change magnitudes of tropical flashes are significantly larger than Florida flashes

Environmental Analysis Of Quasi-Static Electric Field Changes Of Tropical Lightning Flashes

The environmental conditions leading to the bouncing-wave discharge and the subsequent electron beam remain to be investigated in more detailed future studies. The analysis of quasi-static initial electric field changes (IECs) were found at the beginning of all 24 lightning flashes detected within reversal distance (22 Negative Cloud-to-Ground (–CG) and 2 normal Intra-Cloud (IC) flashes) in a tropical storm on June 15th, 2017 close to our station in Malacca, Malaysia (2.314077° N, 102.318282° E). The IECs durations averaged 4.28 ms for –CG flashes (range 1.48 to 9.45 ms) and averaged 11.30 ms for normal ICs flashes (range 7.24 to 15.35 ms). In comparison to Florida storms, the duration of IECs for –CG and IC flashes were 0.18 ms (range 0.08 to 0.33 ms) and 1.53 ms (range 0.18 to 5.70 ms), respectively. Moreover, the magnitudes of E-change for tropical thunderstorm were 0.13 V/m (range 0.03 to 0.44 V/m) for –CG flashes and-0.20 V/m (range-0.13 to-0.27 V/m) for IC flashes. The E-change magnitudes of tropical flashes are significantly larger than Florida flashes

Citric acid: a green cross-linker of biomaterials for biomedical application

The application of biomaterials in biomedicine currently suffers some drawbacks, such as inflammation and immunological responses due to mismatching and/or limited compatibility. Biomaterials that are cross-linked with citric acid (CA), also called citrate-based biomaterials (CBBs), have exhibited advanced in-vitro and in-vivo material properties that make them suitable for various biomedical applications. Tunable mechanical properties, biocompatibility, and biofunctionality are among other factors that make CBBs interesting in this field. To emphasize the safety and greenness nature of CA, in this review, we have highlighted the history, potential considerations of exploration, and a summarized stage-wise criterion for developing CBBs. We also discuss several points of view about the application of CA and CBBs in many different aspects of biomedicine, such as in tissue engineering, cancer therapy, and wound dressings

Photocatalytic Degradation of Synthetic Sulfur Pollutants in Petroleum Fractions under Different pH and Photocatalyst

Thiophene is one of the sulfur compounds in the petroleum fraction that can be harmful to living things and lead to a critical effect on the ecosystem. Photocatalytic degradation is one of the promising methods in treating wastewater as it can mineralization of pollutants into carbon dioxide and water. Other than that, this method is non-toxic and relatively low cost. The production of hydroxyl radicals playing a vital role in the degradation of organic pollutants. It has been claimed that the usage of zinc oxide (ZnO) nanoparticles could give an excellent degradation process as this photocatalyst have high photosensitivity, low cost and chemically stable. However, the preparation method of ZnO nanoparticles will affect the agglomeration, particle size, shape and morphology of particles and lead to influence the photocatalytic activity in degrading thiophene. Therefore, this study focused on the effectiveness of ZnO nanoparticles in the presence of fibrous nanosilica (KCC-1) and polyethylene glycol (PEG) as the capping agent to degrade synthetic thiophene. ZnO/KCC-1 had been synthesized via the precipitation method and characterized by using Fourier Transform Infrared (FTIR). The chemical bond and nature of the photocatalyst from the FTIR results proved that the synthesis process to produce the ZnO/KCC-1 was succeed. The large surface area of KCC-1 increases the effectiveness of ZnO which is supported by the experimental data. Accordingly, the optimum condition for photocatalytic degradation of thiophene is under pH 7 by using ZnO/KCC-1 as photocatalyst. Hence, it is believed that this research could be implemented to remove the thiophene in petroleum fraction from the actual industrial effluents and this can preserve nature in the future

Development of antibacterial, degradable and pH-responsive chitosan/guar gum/polyvinyl alcohol blended hydrogels for wound dressing

The present research is based on the fabrication preparation of CS/PVA/GG blended hydrogel with nontoxic tetra orthosilicate (TEOS) for sustained paracetamol release. Different TEOS percentages were used because of their nontoxic behavior to study newly designed hydrogels’ crosslinking and physicochemical properties. These hydrogels were characterized using Fourier-transform infrared spec-troscopy (FTIR), scanning electron microscopy (SEM), and wetting to determine the functional, surface morphology, hydrophilic, or hydrophobic properties. The swelling analysis in different media, degradation in PBS, and drug release kinetics were conducted to observe their response against corresponding media. The FTIR analysis confirmed the components added and crosslinking between them, and surface morphology confirmed different surface and wetting behavior due to different crosslinking. In various solvents, including water, buffer, and electrolyte solutions, the swelling behaviour of hydrogel was investigated and observed that TEOS amount caused less hydrogel swelling. In acidic pH, hydrogels swell the most, while they swell the least at pH 7 or higher. These hydrogels are pH-sensitive and appropriate for controlled drug release. These hydrogels demonstrated that, as the ionic concentration was increased, swelling decreased due to decreased osmotic pressure in various electrolyte solutions. The antimicrobial analysis revealed that these hydrogels are highly antibacterial against Gram-positive (Staphylococcus aureus and Bacillus cereus) and Gram negative (Pseudomonas aeruginosa and Escherichia coli) bacterial strains. The drug release mechanism was 98% in phosphate buffer saline (PBS) media at pH 7.4 in 140 min. To analyze drug release behaviour, the drug release kinetics was assessed against different mathematical models (such as zero and first order, Higuchi, Baker–Lonsdale, Hixson, and Peppas). It was found that hydrogel (CPG2) follows the Peppas model with the highest value of regression (R2 = 0.98509). Hence, from the results, these hydrogels could be a potential biomaterial for wound dressing in biomedical applications

Novel ceramic hollow fibre membranes contactor derived from kaolin and zirconia for ammonia removal and recovery from synthetic ammonia

The adverse effects of ammonia found in wastewater streams lead to the development of advanced water treatment technology, i.e. membrane contactor (MC). In this study, single layer hollow fibre membrane (SLZK) and dual layer hollow fibre membrane (DLZK) were prepared from zirconia and kaolin and modified into hydrophobic membrane through simple grafting process via fluoroalkylsilane (FAS) agent. The properties of membranes such as morphology, surface roughness, mechanical strength, wettability and liquid entry pressure were analysed through scanning electron microscopy (SEM), atomic force microscopy (AFM), 3-point bending strength, contact angle and LEPw setup. Finally, the performance of the membranes was also investigated towards ammonia removal via membrane contactor system. Our findings showed that hydrophobicity properties significantly improved for both SLZK and DLZK membranes after grafting modification process as indicated by the increase of contact angle value from 5° and 1° to 132.7° and ~180.0° respectively. Based on the morphological analysis, the surface of DLZK showed more porous structure as compared to the SLZK. In addition, DLZK also displayed the highest mechanical strength and contact angle reading of 125 MPa and ~180° respectively. This suggests that the DLZK showed an excellent membrane contactor performance with highest value of mass transfer coefficient (3.77 x 10-5 ms-1) and almost complete removal of ammonia removal (91%). Overall, these results implied that dual layer ceramic membrane developed from kaolin and zirconia could provide the basis for the development of alternative ceramic membrane with excellent properties for membrane contactor system

Application of green technology in gelatin extraction: A review

Growing demands for green and sustainable processing that eliminates the utilization of toxic chemicals and increases efficiency has encouraged the application of novel extraction technologies for the food industry. This review discusses the principles and potential application of several green technology for gelatin extraction. Several novel technologies and their processing efficiency are discussed in this review. Furthermore, factors that affect the quality of the gelatin produced from different sources are also highlighted. The potential application of ultrasound-assisted extraction (UAE), subcritical water extraction, high-pressure processing, and microwave-assisted extraction (MAE) to improve gelatin extraction are addressed. These technologies have the potential to become an efficient extraction method compared to the conventional extraction technologies. Several combinations of green and conventional technologies have been reported to yield promising results. These combinations, especially using conventional pre-treatment and green technologies for extraction, have been found to be more effective in producing gelatin. Since gelatin could be produced from various sources, it exhibits different characteristics; thus, different approaches and extraction method should be identified for specific types of gelatin. Although these technologies have limitations, such as overhydration and sophisticated systems explicitly designed for large-scale production, they are nonetheless more efficient in the long run to safeguard the environment as they reduce solvent usage and carbon footprint along the way