868 results on '"Ang BC"'
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2. Using graphene nanoplatelets nanofluid in a closed-loop evacuated tube solar collector—energy and exergy analysis
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Iranmanesh, S, Silakhori, M, Naghavi, MS, Ang, BC, Ong, HC, Esmaeilzadeh, A, Iranmanesh, S, Silakhori, M, Naghavi, MS, Ang, BC, Ong, HC, and Esmaeilzadeh, A
- Abstract
Recently, nanofluid application as a heat transfer fluid for a closed-loop solar heat collector is receiving great attention among the scientific community due to better performance. The performance of solar systems can be assessed effectively with the exergy method. The present study deals with the thermodynamic performance of the second law analysis using graphene nanoplatelets nanofluids. Second law analysis is the main tool for explaining the exergy output of thermodynamic and energy systems. The performance of the closed-loop system in terms of energy and exergy was determined by analyzing the outcome of field tests in tropical weather conditions. Moreover, three parameters of entropy generation, pumping power and Bejan number were also determined. The flowrates of 0.5, 1 and 1.5 L/min and GNP mass percentage of 0.025, 0.5, 0.075 and 0.1 wt% were used for these tests. The results showed that in a flow rate of 1.5 L/min and a concentration of 0.1 wt%, exergy and thermal efficiencies were increased to about 85.5 and 90.7%, respectively. It also found that entropy generation reduced when increasing the nanofluid concentration. The Bejan number surges up when increasing the concentration, while this number decreases with the enhancement of the volumetric flow rate. The pumping power of the nanofluid-operated system for a 0.1 wt% particle concentration at 0.5 L/min indicated 5.8% more than when pure water was used as the heat transfer fluid. Finally, this investigation reveals the perfect conditions that operate closest to the reversible limit and helps the system make the best improvement.
- Published
- 2021
3. Higher order aberrations and visual function in a young Asian population of high myopes.
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Chay IW, Lin ST, Lim EW, Heng WJ, Bin Ismail MA, Tan MC, Zhao PS, Nah GK, and Ang BC
- Abstract
Purpose: To examine the associations between higher order aberrations (HOAs), visual performance, demographics, and ocular characteristics in a young Asian population with high myopia., Methods: This was a retrospective review of military pre-enlistees conducted between March 2014 to September 2018. Visual acuity and contrast sensitivity were tested under photopic, mesopic and simulated night conditions. Ocular, corneal and internal HOAs were measured with a Hartmann-Shack wavefront aberrometer (KR-1W, Topcon Co., Tokyo, Japan)., Results: 522 eyes of 263 consecutive subjects with severe high myopia (defined as spherical equivalent refraction [SER] ≤ -10.00D) in at least one eye, and high myopia (SER ≤ -6.00D) in the fellow eye, [mean (SD) SER -11.85 (2.03D)] were analysed. The mean (SD) age of subjects was 18.5 (1.6) years. Chinese eyes had significantly greater internal total HOA root-mean-square (RMS) compared to Malay eyes [mean difference (SD) 0.0246 (0.007) μm, p < 0.001). More negative SER was associated with greater ocular total HOA (p = 0.038), primary coma (p = 0.003) and tetrafoil (p = 0.025) RMS, as well as more positive ocular (p = 0.003) and internal primary spherical aberration (p = 0.009). Greater ocular total HOAs was associated with reduced visual acuity in simulated night conditions and low contrast, decreased contrast sensitivity under mesopic and simulated night conditions (all p < 0.05)., Conclusions: Greater HOAs were associated with Chinese ethnicity and more negative SER in a young Asian population with high myopia. Greater HOAs were associated with poorer visual performance in low luminance and reduced contrast conditions., Competing Interests: No conflicting relationship exists for any author., (© 2023 The Authors.)
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- 2023
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4. A novel approach to evaluate the mechanical responses of elastin-like bioresorbable poly(glycolide-co-caprolactone) (PGCL) suture.
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Low YJ, Kittur MI, Andriyana A, Ang BC, and Zainal Abidin NI
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- Polyglycolic Acid chemistry, Sutures, Stress, Mechanical, Tensile Strength, Absorbable Implants, Elastin
- Abstract
Poly(glycolide-co-caprolactone) (PGCL) has become a novice to the bioresorbable suture owing to the synergistic properties taken from the homo-polyglycolide (PGA) and polycaprolactone (PCL) such as excellent bioresorption and flexibility. In addition to under conventional monotonic loading, the understanding of mechanical responses of PGCL copolymers under complex loading conditions such as cyclic and stress relaxation is crucial for its application as a surgical suture. Consequently, the present work focuses on evaluating the mechanical responses of PGCL sutures under monotonic, cyclic, and stress relaxation loading conditions. Under monotonic loading, the stress-strain behavior of the PGCL suture was found to be non-linear with noticeable strain-rate dependence. Under cyclic loading, inelastic responses including stress-softening, hysteresis and permanent set were observed. During cyclic loading, both stress-softening and hysteresis were found to increase with the maximum strain. In multi-step stress relaxation, the PGCL sutures were observed to exhibit a strong viscoelastic response. In an attempt to describe the relationship between the stress-relaxation and strain-induced crystallization (SIC) occurring during the loading and relaxation processes, a schematic illustration of the conformational change of polymer chains in PGCL sutures was proposed in this work. Results showed that SIC was dependent on the strain level as well as the loading and relaxation durations. The inelastic phenomena observed in PGCL sutures can be thus correlated to the combined effect of stress relaxation and SIC., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)
- Published
- 2023
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5. Mechanical Response of Glass-Epoxy Composites with Graphene Oxide Nanoparticles.
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Uppin VS, Gouda PSS, Kittur MI, Andriyana A, Ang BC, Parveez B, Badruddin IA, Javed S, and Kamangar S
- Abstract
Graphene-based fillers possess exceptional properties that encourage researchers toward their incorporation in glass-epoxy (GE) polymer composites. Regarding the mechanical and wear properties of glass-epoxy composites, the effect of graphene oxide (GO) reinforced in glass-epoxy was examined. A decrease in tensile modulus and increase in tensile strength was reported for 1 wt. % of GO. A shift in glass transition temperature T
g was observed with the addition of GO. The cross-link density and storage modulus of the composite decreased with the addition of GO. The decrease in dissipation energy and wear rate was reported with the increase in GO concentration. A simple one-dimensional damage model of nonlinear nature was developed to capture the stress-strain behavior of the unfilled and filled glass-epoxy composite. Tensile modulus E , Weibull scale parameter σo , and Weibull shape parameter β were considered to develop the model. Finally, to understand the failure mechanisms in GO-filled composites, a scanning electron microscopic (SEM) examination was carried out for tensile fractured composites.- Published
- 2022
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6. A review on synthesis, modification method, and challenges of light-driven H 2 evolution using g-C 3 N 4 -based photocatalyst.
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Abu-Sari SM, Daud WMAW, Patah MFA, and Ang BC
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- Catalysis, Hydrogen, Water
- Abstract
The energy scarcity is exacerbating and needs an urgent solution. The most plausible solution to address the forthcoming energy scarcity is to diversify the energy sources. Developing the water-splitting process (WSP) efficiency depends on solar energy representing "21st-century dream technology". We present a comprehensive review of related papers employing graphitic carbon nitride (g-C
3 N4 ) as pure, doped, or composite nanostructure in the evolution of hydrogen from water dissociation under simulated sunlight irradiation, mainly in the last ten years. Herein, after a concise introduction to the main principle of the water-splitting process, the methods to synthesize, modify and upgrade the photocatalytic performance of g-C3 N4 were reviewed in detail. Moreover, the main challenges of using g-C3 N4 -based photocatalytic material in WSP have been mentioned. The report mainly targets the g-C3 N4 character, synthesis method, photocatalytic activity, and strategies toward enhancing photoreactivity under visible light, along with the reusability of the fabricated nanohybrid catalysts. Above and over, this review suggests the potential of g-C3 N4 to produce green H2 from water at a competitive price, which can contribute to satisfying the global energy sector demand and suppressing global warming., (Copyright © 2022 Elsevier B.V. All rights reserved.)- Published
- 2022
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7. "Culture-positive exogenous endophthalmitis related to XEN45 gel stent implantation".
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Ng AW, Yip VC, Ang BC, Yip LW, and Lim BA
- Abstract
Purpose: The XEN45 gel stent implant (Allergen, CA, USA) is one of many micro-invasive surgical options available to glaucomatologists. Our case series describes the presentation, treatment, and possible risk factors of XEN45 gel stent related endophthalmitis., Observations: A 71 year old Chinese man and a 88 year old Caucasian woman underwent XEN45 gel stent implantation for primary open angle glaucoma. They presented with endophthalmitis at 7 and 4 months post-surgery respectively. The first patient had stent exposure with blebitis while the second patient did not show any signs of conjunctival defect, stent exposure, bleb leak nor blebitis. Both patients were treated immediately with intravitreal, topical and systemic antibiotics, followed by early vitrectomy. The implant was removed in the first, but not in the second patient. Vitreous cultures grew Streptococcus Viridans in the first patient and Haemophilus influenzae in the other. Unfortunately, the first patient eventually sustained a total retinal detachment requiring surgery and did not recover his vision. The second patient however, recovered with a good Snellen's visual acuity of 6/9 and maintenance of good intraocular pressure and bleb formation., Conclusions: Exogenous endophthalmitis related to XEN45 gel stent implantation is a rare but devastating complication. The risks factors identified were multiple post-operative procedures, bleb exposure, conjunctival defect, use of antifibrotics, blepharitis and prolonged post-operative antibiotics. XEN45 gel stent implant provides a different challenge to ophthalmologists compared to trabeculectomy as more post-operative procedures are required to prevent subconjunctival scarring. Great care should be taken to individualize the use of antifibrotics in each patient to balance the risk of subconjunctival fibrosis with the risk of infection. In patients with stent exposure we propose early closure of the conjunctiva to close off the portal of entry for pathogens and reduce the need for prophylactic topical antibiotics., Competing Interests: Ang, Bryan C: Consultant and travel assistance (Allergan). Yip, Leonard W: Consultant and travel assistance (Allergan). The following authors have no financial disclosures: Ng, Aaron W. Yip, Vivien C. Lim, Boon Ang., (© 2022 The Authors.)
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- 2022
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8. Fabrication and Thermo-Electro and Mechanical Properties Evaluation of Helical Multiwall Carbon Nanotube-Carbon Fiber/Epoxy Composite Laminates.
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Ali A, Andriyana A, Hassan SBA, and Ang BC
- Abstract
The development of advanced composite materials has taken center stage because of its advantages over traditional materials. Recently, carbon-based advanced additives have shown promising results in the development of advanced polymer composites. The inter- and intra-laminar fracture toughness in modes I and II, along with the thermal and electrical conductivities, were investigated. The HMWCNTs/epoxy composite was prepared using a multi-dispersion method, followed by uniform coating at the mid-layers of the CF/E prepregs interface using the spray coating technique. Analysis methods, such as double cantilever beam (DCB) and end notched flexure (ENF) tests, were carried out to study the mode I and II fracture toughness. The surface morphology of the composite was analyzed using field emission scanning electron microscopy (FESEM). The DCB test showed that the fracture toughness of the 0.2 wt.% and 0.4 wt.% HMWCNT composite laminates was improved by 39.15% and 115.05%, respectively, compared with the control sample. Furthermore, the ENF test showed that the mode II interlaminar fracture toughness for the composite laminate increased by 50.88% and 190%, respectively. The FESEM morphology results confirmed the HMWCNTs bridging at the fracture zones of the CF/E composite and the improved interlaminar fracture toughness. The thermogravimetric analysis (TGA) results demonstrated a strong intermolecular bonding between the epoxy and HMWCNTs, resulting in an improved thermal stability. Moreover, the differential scanning calorimetry (DSC) results confirmed that the addition of HMWCNT shifted the T
g to a higher temperature. An electrical conductivity study demonstrated that a higher CNT concentration in the composite laminate resulted in a higher conductivity improvement. This study confirmed that the demonstrated dispersion technique could create composite laminates with a strong interfacial bond interaction between the epoxy and HMWCNT, and thus improve their properties.- Published
- 2021
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9. Recent Advances in Scaffolding from Natural-Based Polymers for Volumetric Muscle Injury.
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Nuge T, Liu Z, Liu X, Ang BC, Andriyana A, Metselaar HSC, and Hoque ME
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- Biocompatible Materials therapeutic use, Extracellular Matrix drug effects, Humans, Muscle, Skeletal injuries, Muscle, Skeletal pathology, Muscular Diseases pathology, Polymers therapeutic use, Wound Healing drug effects, Muscle, Skeletal drug effects, Muscular Diseases drug therapy, Regeneration drug effects, Tissue Scaffolds chemistry
- Abstract
Volumetric Muscle Loss (VML) is associated with muscle loss function and often untreated and considered part of the natural sequelae of trauma. Various types of biomaterials with different physical and properties have been developed to treat VML. However, much work remains yet to be done before the scaffolds can pass from the bench to the bedside. The present review aims to provide a comprehensive summary of the latest developments in the construction and application of natural polymers-based tissue scaffolding for volumetric muscle injury. Here, the tissue engineering approaches for treating volumetric muscle loss injury are highlighted and recent advances in cell-based therapies using various sources of stem cells are elaborated in detail. An overview of different strategies of tissue scaffolding and their efficacy on skeletal muscle cells regeneration and migration are presented. Furthermore, the present paper discusses a wide range of natural polymers with a special focus on proteins and polysaccharides that are major components of the extracellular matrices. The natural polymers are biologically active and excellently promote cell adhesion and growth. These bio-characteristics justify natural polymers as one of the most attractive options for developing scaffolds for muscle cell regeneration.
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- 2021
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10. Core-Shell Fibers: Design, Roles, and Controllable Release Strategies in Tissue Engineering and Drug Delivery.
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Abdullah MF, Nuge T, Andriyana A, Ang BC, and Muhamad F
- Abstract
The key attributes of core-shell fibers are their ability to preserve bioactivity of incorporated-sensitive biomolecules (such as drug, protein, and growth factor) and subsequently control biomolecule release to the targeted microenvironments to achieve therapeutic effects. Such qualities are highly favorable for tissue engineering and drug delivery, and these features are not able to be offered by monolithic fibers. In this review, we begin with an overview on design requirement of core-shell fibers, followed by the summary of recent preparation methods of core-shell fibers, with focus on electrospinning-based techniques and other newly discovered fabrication approaches. We then highlight the importance and roles of core-shell fibers in tissue engineering and drug delivery, accompanied by thorough discussion on controllable release strategies of the incorporated bioactive molecules from the fibers. Ultimately, we touch on core-shell fibers-related challenges and offer perspectives on their future direction towards clinical applications., Competing Interests: The authors declare no conflicts of interest.
- Published
- 2019
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11. Degradation of methyl orange and congo red by using chitosan/polyvinyl alcohol/TiO 2 electrospun nanofibrous membrane.
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Habiba U, Lee JJL, Joo TC, Ang BC, and Afifi AM
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- Adsorption, Membranes, Artificial, Nanofibers ultrastructure, Spectrum Analysis, Tensile Strength, Thermodynamics, Water Pollutants, Chemical chemistry, Water Purification, Azo Compounds chemistry, Chitosan chemistry, Congo Red chemistry, Nanofibers chemistry, Polyvinyl Alcohol chemistry, Titanium chemistry
- Abstract
In this study, chitosan/polyvinyl alcohol/TiO
2 nanofiber was fabricated via electrospinning at a pump rate of 1.5 mL/h and voltage 6 kV. Field-emission scanning electron microscopic images showed bead free finer nanofiber. Fourier transform infrared spectra proved the formation of strong bond among chitosan, polyvinyl alcohol and TiO2 . X-ray powder diffraction showed that TiO2 became amorphous in the composite nanofiber. Toughness and thermal stability of the chitosan/PVA nanofibrous membrane was increased with addition TiO2 . The chitosan/PVA/TiO2 nanofibrous membrane was stable at basic medium. But degraded in acidic and water medium after 93 and 162 h, respectively. The adsorption mechanism of congo red obeyed the Langmuir isotherm model. On the other hand, adsorption characteristic of methyl orange fitted well with both Langmuir and Freundlich isotherm models. The maximum adsorption capacity of the resulting membrane for congo red and methyl orange is 131 and 314 mg/g, respectively. However, a high dose of adsorbent was required for congo red., (Copyright © 2019 Elsevier B.V. All rights reserved.)- Published
- 2019
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12. Adsorption study of methyl orange by chitosan/polyvinyl alcohol/zeolite electrospun composite nanofibrous membrane.
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Habiba U, Siddique TA, Li Lee JJ, Joo TC, Ang BC, and Afifi AM
- Abstract
The chitosan/polyvinyl Alcohol/zeolite electrospun composite nanofibrous membrane was fabricated for adsorption of methyl orange. The EDX, TGA and tensile test were carried out for the characterization of the membrane. The Young's Modulus of the nanofibrous membranes increased by more than 100% with the addition of zeolite to chitosan/PVA. The batch adsorption tests were conducted by varying the initial concentration of methyl orange, contact time and pH of the dye solution. UV-vis results showed that most of the dye was adsorbed within 6 min. An adsorption kinetic study was carried out using the pseudo-second-order kinetic model, Lagergren-first-order model and intra particle diffusion model. The adsorption kinetics obeyed the Pseudo second order model. The adsorption mechanism was analyzed using the Langmuir and Freundlich isotherm model. The experimental data fits well with the Freundlich model. The adsorption capacity of the membrane was 153 mg/g. Adsorption capacity was decreased with increasing pH value. The resulting nanofiber became less active over methyl orange after several runs., (Copyright © 2018 Elsevier Ltd. All rights reserved.)
- Published
- 2018
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13. Herpes Simplex Acute Retinal Necrosis Presenting as Unilateral Disc Swelling in Young Immunocompetent Patients.
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Koh YT, Ang BC, Ho SL, Beng Teoh SC, and Agrawal R
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- Adult, Antiviral Agents therapeutic use, Eye Infections, Viral drug therapy, Eye Infections, Viral virology, Fluorescein Angiography, Herpes Simplex drug therapy, Herpes Simplex virology, Herpesvirus 1, Human isolation & purification, Herpesvirus 2, Human isolation & purification, Humans, Immunocompetence, Immunocompromised Host, Male, Optic Neuritis diagnosis, Optic Neuritis drug therapy, Optic Neuritis virology, Papilledema drug therapy, Papilledema virology, Retinal Necrosis Syndrome, Acute drug therapy, Retinal Necrosis Syndrome, Acute virology, Retrospective Studies, Vitreous Body virology, Eye Infections, Viral diagnosis, Herpes Simplex diagnosis, Papilledema diagnosis, Retinal Necrosis Syndrome, Acute diagnosis
- Abstract
Purpose: To report two cases of young immunocompetent males with herpes simplex acute retinal necrosis (HSV ARN) with initial diagnosis of unilateral disc swelling., Methods: Retrospective case series., Results: Two young immunocompetent males who were diagnosed to have unilateral disc swelling were treated as presumed optic neuritis and started on systemic steroids. On dilated fundal examination, unilateral retinitis and vasculitis was found after 2-3 days of systemic steroids and the diagnosis of ARN was made. Tetraplex vitreous tap subsequently returned as HSV-2 and HSV for the first and second patient, respectively. Both patients had no significant systemic medical history and tested negative for human immunodeficiency virus (HIV). Despite aggressive treatment, both patients developed profound visual morbidity., Conclusions: Close monitoring of patients with unilateral disc swelling and dilated fundus evaluation is critical, particularly upon initiation of systemic steroid therapy, even if immunocompetent, as misdiagnoses can result in potentially devastating consequences.
- Published
- 2017
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14. Effect of deacetylation on property of electrospun chitosan/PVA nanofibrous membrane and removal of methyl orange, Fe(III) and Cr(VI) ions.
- Author
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Habiba U, Siddique TA, Talebian S, Lee JJL, Salleh A, Ang BC, and Afifi AM
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- Acetylation, Adsorption, Ions chemistry, Azo Compounds chemistry, Chitosan chemistry, Chromium chemistry, Iron chemistry, Nanofibers chemistry, Polyvinyl Alcohol chemistry
- Abstract
In this study, effect of degree of deacetylation on property and adsorption capacity of chitosan/polyvinyl Alcohol electrospun membrane has been investigated. Resulting nanofibers were characterized by FESEM, FTIR, XRD, TGA, tensile testing, weight loss test and adsorption test. FESEM result shows, finer nanofiber was fabricated from 42h hydrolyzed chitosan and PVA blend solution. FTIR and XRD result showed a strong interaction between chitosan and polyvinyl alcohol. Higher tensile strength was observed for the nanofiber having 42h hydrolyzed chitosan. Blend solution of chitosan/PVA having low DD chitosan had higher viscosity. The nanofibrous membrane was stable in distilled water, acidic and basic medium. The isotherm study shows that the adsorption capacity (q
m ) of nanofiber containing higher DD chitosan was higher for Cr(VI). In contrary, the membrane containing chitosan with lower DD showed the higher adsorption capacity for Fe(III) and methyl orange. Moreover, the effect of DD on removal percentage of adsorbate was dependent on the initial concentration of the adsorbate., (Copyright © 2017 Elsevier Ltd. All rights reserved.)- Published
- 2017
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15. Effect of degree of deacetylation of chitosan on adsorption capacity and reusability of chitosan/polyvinyl alcohol/TiO 2 nano composite.
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Habiba U, Joo TC, Siddique TA, Salleh A, Ang BC, and Afifi AM
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- Acetylation, Adsorption, Hydrolysis, Kinetics, Temperature, Chitosan chemistry, Nanocomposites chemistry, Polyvinyl Alcohol chemistry, Titanium chemistry
- Abstract
The chitosan/polyvinyl alcohol/TiO
2 composite was synthesized. Two different degrees of deacetylation of chitosan were prepared by hydrolysis to compare the effectiveness of them. The composite was analyzed via field emission scanning electron microscopy, Fourier transform infrared, X-ray diffraction, thermal gravimetric analysis, weight loss test and adsorption study. The FTIR and XRD results proved the interaction among chitosan, PVA and TiO2 without any chemical reaction. It was found that, chitosan with higher degree of deacetylation has better stability. Furthermore, it also showed that higher DD of chitosan required less time to reach equilibrium for methyl orange. The adsorption followed the pseudo-second-order kinetic model. The Langmuir and Freundlich isotherm models were fitted well for isotherm study. Adsorption capacity was higher for the composite containing chitosan with higher DD. The dye removal rate was independent of the dye's initial concentration. The adsorption capacity was increased with temperature and it was found from reusability test that the composite containing chitosan with higher DD is more reusable. It was notable that adsorption capacity was even after 15 runs. Therefore, chitosan/PVA/TiO2 composite can be a very useful material for dye removal., (Copyright © 2017 Elsevier B.V. All rights reserved.)- Published
- 2017
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16. Synthesis of chitosan/polyvinyl alcohol/zeolite composite for removal of methyl orange, Congo red and chromium(VI) by flocculation/adsorption.
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Habiba U, Siddique TA, Joo TC, Salleh A, Ang BC, and Afifi AM
- Abstract
A chitosan/polyvinyl alcohol (PVA)/zeolite composite was fabricated in this study. The composite was analyzed through field emission scanning electron microscopy, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis, and weight loss test. FTIR and XRD results revealed a strong interaction among chitosan, PVA, and zeolite. Weight loss test results indicated that the composite was stable in acidic and basic media. Congo red was removed through flocculation, and the removal rate was 94% at an initial concentration of 100mg/L for a dose of 1g/L. The removal rate of methyl orange was controlled by adsorption at an initial concentration of less than 100mg/L. Flocculation occurred at high concentrations. The removal rate was also 94% at an initial concentration of 500mg/L for a dose of 5g/L. The adsorption behavior of the composite for the removal of methyl orange and Cr(VI) was described by using a pseudo-second-order kinetic model. The adsorption capacity of the composite for Cr(VI) was 450mg/g. Therefore, the synthesized composite exhibited versatility during the removal of dyes and heavy metals., (Copyright © 2016 Elsevier Ltd. All rights reserved.)
- Published
- 2017
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17. Adsorption of divalent heavy metal ion by mesoporous-high surface area chitosan/poly (ethylene oxide) nanofibrous membrane.
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Shariful MI, Sharif SB, Lee JJL, Habiba U, Ang BC, and Amalina MA
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- Adsorption, Hydrogen-Ion Concentration, Kinetics, Chitosan analysis, Ethylene Oxide chemistry, Metals, Heavy isolation & purification, Nanofibers
- Abstract
In this study, chitosan/poly (ethylene oxide) nanofibres were fabricated at different chitosan:PEO weight ratio by electrospinning process. The effects of chitosan/PEO composition onto adsorption capability for Cu(II), Zn(II) and Pb(II) ions were studied. Formation of beadless fibres were achieved at 60:40 chitosan:PEO ratio. Average fiber diameter, maximum tensile strength and the specific surface area of the beadless fibres were found to be 115±31nm, 1.58MPa and 218m
2 /g, respectively. Chitosan/PEO composition that produced beadless fibres tend to possess higher hydrophilicity and maximum specific surface area. These characteristics lead the beadless fibres to the maximum adsorption capability. Adsorption equilibrium data were analysed by Langmuir and Freundlich isotherm. Freundlich isotherm showed the better fit with the experimental data and proved the existence of the monolayer adsorption conditions. The maximum adsorption capacity of the beadless fibres for Cu(II), Zn(II) and Pb(II) ions were found to be 120, 117 and 108mgg-1 , respectively., (Copyright © 2016. Published by Elsevier Ltd.)- Published
- 2017
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18. Evaluation of Various Cooling Systems After Exercise-Induced Hyperthermia.
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Tan PM, Teo EY, Ali NB, Ang BC, Iskandar I, Law LY, and Lee JK
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- Cross-Over Studies, Exercise Test, Heart Rate physiology, Heat Stroke etiology, Heat Stroke physiopathology, Humans, Male, Perception physiology, Physical Exertion, Thermosensing, Young Adult, Cryotherapy, Exercise physiology, Heat Stroke therapy
- Abstract
Context: Rapid diagnosis and expeditious cooling of individuals with exertional heat stroke is paramount for survival., Objective: To evaluate the efficacy of various cooling systems after exercise-induced hyperthermia., Design: Crossover study., Setting: Laboratory., Patients or Other Participants: Twenty-two men (age = 24 ± 2 years, height = 1.76 ± 0.07 m, mass = 70.7 ± 9.5 kg) participated., Intervention(s): Each participant completed a treadmill walk until body core temperature reached 39.50°C. The treadmill walk was performed at 5.3 km/h on an 8.5% incline for 50 minutes and then at 5.0 km/h until the end of exercise. Each participant experienced 4 cooling phases in a randomized, repeated-crossover design: (1) no cooling (CON), (2) body-cooling unit (BCU), (3) EMCOOLS Flex.Pad (EC), and (4) ThermoSuit (TS). Cooling continued for 30 minutes or until body core temperature reached 38.00°C, whichever occurred earlier., Main Outcome Measure(s): Body core temperature (obtained via an ingestible telemetric temperature sensor) and heart rate were measured continuously during the exercise and cooling phases. Rating of perceived exertion was monitored every 5 minutes during the exercise phase and thermal sensation every minute during the cooling phase., Results: The absolute cooling rate was greatest with TS (0.16°C/min ± 0.06°C/min) followed by EC (0.12°C/min ± 0.04°C/min), BCU (0.09°C/min ± 0.06°C/min), and CON (0.06°C/min ± 0.02°C/min; P < .001). The TS offered a greater cooling rate than all other cooling modalities in this study, whereas EC offered a greater cooling rate than both CON and BCU (P < .0083 for all). Effect-size calculations, however, showed that EC and BCU were not clinically different., Conclusion: These findings provide objective evidence for selecting the most effective cooling system of those we evaluated for cooling individuals with exercise-induced hyperthermia. Nevertheless, factors other than cooling efficacy need to be considered when selecting an appropriate cooling system.
- Published
- 2017
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19. Chitosan/(polyvinyl alcohol)/zeolite electrospun composite nanofibrous membrane for adsorption of Cr 6+ , Fe 3+ and Ni 2 .
- Author
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Habiba U, Afifi AM, Salleh A, and Ang BC
- Abstract
In this study, chitosan/polyvinyl alcohol (PVA)/zeolite nanofibrous composite membrane was fabricated via electrospinning. First, crude chitosan was hydrolyzed with NaOH for 24h. Afterward, hydrolyzed chitosan solution was blended with aqueous PVA solution in different weight ratios. Morphological analysis of chitosan/PVA electrospun nanofiber showed a defect-free nanofiber material with 50:50 weight ratio of chitosan/PVA. Subsequently, 1wt.% of zeolite was added to this blended solution of 50:50 chitosan/PVA. The resulting nanofiber was characterized with field emission scanning electron microscopy, X-Ray diffraction, Fourier transform infrared spectroscopy, swelling test, and adsorption test. Fine, bead-free nanofiber with homogeneous nanofiber was electrospun. The resulting membrane was stable in distilled water, acidic, and basic media in 20 days. Moreover, the adsorption ability of nanofibrous membrane was studied over Cr (VI), Fe (III), and Ni (II) ions using Langmuir isotherm. Kinetic parameters were estimated using the Lagergren first-order, pseudo-second-order, and intraparticle diffusion kinetic models. Kinetic study showed that adsorption rate was high. However, the resulting nanofiber membrane showed less adsorption capacity at high concentration. The adsorption capacity of nanofiber was unaltered after five recycling runs, which indicated the reusability of chitosan/PVA/zeolite nanofibrous membrane. Therefore, chitosan/PVA/zeolite nanofiber can be a useful material for water treatment at moderate concentration of heavy metals., (Copyright © 2016 Elsevier B.V. All rights reserved.)
- Published
- 2017
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20. Whole-body protein turnover in response to hyperinsulinemia in humans postabsorptively with [15N]glycine as tracer
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Ang, BC, primary, Halliday, D, additional, and Powell-Tuck, J, additional
- Published
- 1995
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21. Adsorption and photocatalytic degradation of anionic dyes on Chitosan/PVA/Na-Titanate/TiO2 composites synthesized by solution casting method.
- Author
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Habiba U, Islam MS, Siddique TA, Afifi AM, and Ang BC
- Subjects
- Adsorption, Catalysis, Coloring Agents isolation & purification, Molecular Weight, Solutions, Water Pollutants, Chemical chemistry, Water Pollutants, Chemical isolation & purification, Chitosan chemistry, Coloring Agents chemistry, Oxides chemistry, Photolysis, Polyvinyl Alcohol chemistry, Titanium chemistry
- Abstract
Chitosan/PVA/Na-titanate/TiO2 composite was synthesized by solution casting method. The composite was analyzed via Fourier Transform Infrared Spectroscopy, X-ray diffraction, Field Emission Scanning Electron Microscopy, Thermal gravimetric analysis and water stability test. Incorporation of Na-titanate shown decrease of crystallinity for chitosan but increase water stability. However, the composite structure was deteriorated with considerable weight loss in acidic medium. Two anionic dyes, methyl orange and congo red were used for the adsorption test. The adsorption behavior of the composites were described by pseudo-second-order kinetic model and Lagergren-first-order model for methyl orange and congo red, respectively. For methyl orange, adsorption was started with a promising decolorization rate. 99.9% of methyl orange dye was removed by the composite having higher weightage of chitosan and crystalline TiO2 phase. On the other hand, for the congo red the composite having higher chitosan and Na-titanate showed an efficient removal capacity of 95.76%. UV-vis results showed that the molecular backbone of methyl orange and congo red was almost destroyed when equilibrium was obtained, and the decolorization rate was reaching 100%. Kinetic study results showed that the photocatalytic degradation of methyl orange and congo red could be explained by Langmuir-Hinshelwood model. Thus, chitosan/PVA/Na-titanate/TiO2 possesses efficient adsorptivity and photocatalytic property for dye degradation., (Copyright © 2016 Elsevier Ltd. All rights reserved.)
- Published
- 2016
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22. Risk factors for early-onset corneal haze after photorefractive keratectomy in an Asian population: Outcomes from the Singapore Armed Forces Corneal Refractive Surgery Programme 2006 to 2013.
- Author
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Ang BC, Foo RC, Lim EW, Tan MM, Nah GK, Thean LS, Tan CW, and Zhao PS
- Subjects
- Adolescent, Adult, Female, Humans, Keratectomy, Lasers, Excimer, Male, Retrospective Studies, Risk Factors, Treatment Outcome, Visual Acuity, Young Adult, Cornea pathology, Myopia therapy, Photorefractive Keratectomy adverse effects
- Abstract
Purpose: To assess the incidence and risk factors for early corneal haze after myopic photorefractive keratectomy (PRK)., Setting: Tertiary eye center, Singapore., Design: Retrospective case series., Methods: The refractive results and corneal haze severity 3 months after PRK were analyzed. Eyes were categorized into 4 groups based on haze severity. Multivariate ordinal logistic regression analysis adjusting for age, ethnicity, sex, use of intraoperative mitomycin-C (MMC), preoperative sphere, and preoperative cylinder was performed., Results: The study reviewed data from 177 patients (347 eyes) with a mean age of 22.6 years ± 4.1 (SD). The majority of the patients were Chinese (98.3%) and men (98.3%). The mean preoperative spherical equivalent (SE) was -3.34 ± 1.19 diopters (D). One hundred thirty-five eyes (38.9%) had PRK with MMC. Ten eyes (2.9%) had enhancement surgery. The overall efficacy index was 0.88 and the safety index was 1.07. At 3 months, 187 eyes (53.9%) had no haze, 76 eyes (21.9%) had a haze grade of more than 0 and less than 1, 76 eyes (21.9%) had a haze grade of 1 or more and less than 2, and 8 eyes (2.3%) had grade 2 haze. Higher degrees of myopia (odds ratio [OR], 1.36; 95% confidence interval [CI], 1.13-1.63; P = .001) and astigmatism (OR, 1.56; 95% CI, 1.09-2.24; P = .014) were associated with increased severity of corneal haze, whereas older age (OR, 0.94; 95% CI, 0.88-0.99; P = .023) had a protective effect., Conclusion: Myopia and astigmatism were associated with increased severity of haze, and older age was protective against early corneal haze development after PRK in an Asian population., Financial Disclosure: None of the authors has a financial or proprietary interest in any material or method mentioned., (Copyright © 2016 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.)
- Published
- 2016
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23. Changes in Japanese eyes after laser peripheral iridotomy: an anterior segment optical coherence tomography study.
- Author
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Ang BC, Nongpiur ME, Aung T, Mizoguchi T, and Ozaki M
- Subjects
- Aged, Aged, 80 and over, Argon Plasma Coagulation, Asian People ethnology, Female, Glaucoma, Angle-Closure ethnology, Glaucoma, Angle-Closure pathology, Gonioscopy, Humans, Intraocular Pressure, Japan epidemiology, Male, Prospective Studies, Tonometry, Ocular, Anterior Eye Segment pathology, Glaucoma, Angle-Closure surgery, Iridectomy, Iris surgery, Laser Coagulation, Tomography, Optical Coherence
- Abstract
Background: The aim was to investigate the changes in anterior segment parameters, as assessed by anterior segment optical coherence tomography in Japanese subjects after laser peripheral iridotomy (LPI)., Design: This was a prospective observational study., Participants: The participants include 72 subjects with angle closure including primary angle closure suspect (PACS), primary angle closure (PAC), and primary angle closure glaucoma (PACG)., Methods: Anterior segment optical coherence tomography parameters was measured by customized software. Complete data of 51 subjects were available for final analysis., Main Outcome Measures: These were the following parameters: angle opening distance, trabecular-iris space area, anterior chamber depth, width, area and volume (iris thickness, curvature, and area, and lens vault (LV)., Results: A total of 25 PACS, 17 PAC and 9 PACG were included. Mean age was 74.7 ± 6.7 years, and majority were women (80.4%). Following LPI, there was a significant increase in mean gonioscopic angle width (1.16 vs. 1.93, P < 0.001) and a corresponding increase in angle opening distance, trabecular-iris space area, and angle recess area (all P < 0.001). The anterior chamber area (P < 0.001), anterior chamber volume (P < 0.001) and anterior chamber depth (P = 0.003) increased significantly; and iris curvature (P < 0.001) was significantly reduced. There were no significant changes in anterior chamber width, LV, iris thickness and area. Age-adjusted and gender-adjusted analysis for predictors of percentage change in angle opening distance 750 showed significant association with greater baseline LV (β = 0.32, P = 0.03). No significant differences were noted in the mean percentage change in parameters between the PACS and PAC-PACG., Conclusions: An increase in anterior chamber dimensions, angle widening and iris flattening; with a constant LV, iris thickness and iris area after LPI was demonstrated in Japanese eyes with angle closure., (© 2015 Royal Australian and New Zealand College of Ophthalmologists.)
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- 2016
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24. Electro-spun nanofibers-based triboelectric nanogenerators in wearable electronics: status and perspectives.
- Author
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Tao, Deyin, Su, Ping, Chen, Aiping, Gu, Dawei, Eginligil, Mustafa, and Huang, Wei
- Subjects
NANOGENERATORS ,ENERGY harvesting ,WEARABLE technology ,PHYSICAL & theoretical chemistry ,ENERGY consumption - Abstract
Electro-Spun nanofibers (ESNs), with their design flexibility, tailorable morphologies, and high surface area, are well-favored as triboelectric nanogenerator (TENG) materials for wearable electronics. Here, various aspects of ESNs-based wearable TENGs were examined. After introducing the most common TENG operating modes, an insightful overview of wearable TENG applications based on ESNs was presented. In this survey, a special attention is paid to wearable sensing, human-machine interaction, self-powered devices, and amplified energy harvesting. Efforts towards improving energy conversion efficiency, material durability, and compatibility with diverse wearable platforms were visited. Finally, a perspective based on particularly material aspect of ESNs is given, which could be insightful in tackling prevailing challenges and giving birth to new directions. [ABSTRACT FROM AUTHOR]
- Published
- 2025
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25. Anterior segment features in neovascular glaucoma: An ultrasound biomicroscopy study.
- Author
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Guo, Liang, Liu, Yuefeng, Huang, Xiaoxia, Liu, Qingyi, Shen, Zhimin, Wu, Yan, and Yang, Lu
- Published
- 2025
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26. Development and characterization of Abutilon indicum (Indian mallow) leaf extract loaded electrospun nanofibres.
- Author
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Tharakeswari, S., R K, Shobana, R, Reena Sharon, V, Shrivatsan, and H, Ashik Ahamed
- Subjects
MEDICINAL plants ,AIR filters ,POLYVINYL alcohol ,SURFACE morphology ,TISSUE engineering - Abstract
Herbal functionalized nanofibres are widely used in wound healing, tissue engineering, and air filters due to their efficient antimicrobial properties. Spinning nanofibres using herbs requires initial studies to check the compatibility of the herb, nanofibre formation, and spinnability. Efforts are being made to spin nanofibres using Abutilon indicum. Nanofibres produced using electrospinning techniques excel in unique structural and functional properties. Their structure aids in encapsulating active substances and controlled release of these substances. Abutilon indicum, also known as Indian mallow or Thuthi leaf, is a plant with various medicinal claims and antimicrobial properties. The current study focuses on developing nanofibres using the electrospinning technique with Polyvinyl Alcohol (PVA) polymer and Indian mallow extract (IME). Nanofibres were developed with PVA/IME in different proportions. The developed nanofibres were characterized for surface morphology, Fourier-transform infrared spectrum, material thickness, swelling ratio, tensile strength, and antimicrobial property. The addition of IME to PVA did not affect the spinnability of the nanofibres. Among the samples developed with different ratios, the 50:50 PVA/IME sample was observed to have enhanced antimicrobial activity due to the higher proportion of IME within the polymer. [ABSTRACT FROM AUTHOR]
- Published
- 2025
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27. Experimental investigation and model analysis of uniaxial compressive behavior, micro properties and sustainability of fiber-reinforced concrete designed by cost-efficiency fibers.
- Author
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Jin, Hesong, Xu, Haiyan, Cai, Chang, Chen, Lingkun, Wang, Tianchun, Shen, Lixue, Wang, Zhijie, Chen, Tiewei, and Ngo, Tuan
- Published
- 2024
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28. Amorphous carbon nanotubes as a potent remover of textile dyes: methylene blue and malachite green.
- Author
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Banerjee, D., Garg, N., Chauhan, K., Parashar, M., and Kumar, P.
- Published
- 2024
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29. Simulation of nanofluid convective flow inside a complex solar thermal system.
- Author
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Tabarhoseini, S. Mojtaba, Jafaryar, M., and Sheikholeslami, M.
- Subjects
COMPUTATIONAL fluid dynamics ,CONVECTIVE flow ,SOLAR collectors ,SOLAR energy ,SOLAR heating - Abstract
Today's world witnesses an unprecedented augmentation in energy consumption which has tipped the balance of attention toward the renewable energies, especially solar energy as the most promising type. With recent developments in the field of solar heating units, evacuated tube solar units have played a prominent role in solar energy absorption process in recent years due to the existence of a vacuum envelope in the structure of the tubes. Following this, a three-dimensional transient numerical study has been carried out by employing computational fluid dynamics aimed to appraise the water flow, natural circulation process and convective rate inside the evacuated tube along with a storage tank. A comparison has been made using water and CuO/H
2 O nanomaterial as the operate fluid for the purpose of evaluating the efficacy of nanofluid on the functionality of the system. The results in the form of velocity distribution, temperature and velocity contours served as an array of reasons on serviceability of CuO nanoparticles in the given application. This is evidenced by the natural circulation rate and heat transfer sustaining more desirable magnitudes, while observing an increase in the average temperatures of the tube and tank, respectively. Implementation of CuO/water over plain water has been reasserted categorically and thus justified. [ABSTRACT FROM AUTHOR]- Published
- 2024
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30. Biopolymer-coated magnesium-alloy-based multi-functional bio-nanocomposite scaffolds.
- Author
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Garimella, Adithya, Rathi, Darshan, Jangid, Rajesh, Khare, Deepak, Dubey, Ashutosh Kumar, Ghosh, Subrata Bandhu, and Bandyopadhyay-Ghosh, Sanchita
- Subjects
IMMERSION in liquids ,CANCELLOUS bone ,BONE growth ,COMPRESSIVE strength ,BONE cells ,BIODEGRADABLE materials ,MAGNESIUM alloys - Abstract
PM-technique produced magnesium-alloy bio-nanocomposite porous scaffolds with carbamide as porogen. Mg samples were alloyed with Ca, Zn, and Sr for enhanced mechanical performance and deterioration resistance. Nano-fluorcanasite, a bioactive-chain-silicate glass-ceramic reinforcement, was added to the magnesium-metal-matrix to induce new bone cell growth. Dip-coating was used to coat bare magnesium samples with PCL. FE-SEM-EDS findings showed gradient-porosity and coating thickness of 70–90 µm. After 28-days of immersion, C-S1 and C-S2 had compressive and residual-compressive strengths 10% to 15% higher than C-S0. As Ca, Zn, and Sr hydroxyapatites formed, C-S1 and C-S2 degradation reduced with immersion time. Biodegradation matches immersion liquid pH, hydrogen gas evolution, and cytocompatibility. As porosity increased from 50% to 60%, scaffold compressive strength and modulus decreased but remained in line with that of a human cancellous bone. PCL-coated customized nanocomposite magnesium alloy-based biomaterials may be promising biodegradable bone tissue repair implant materials with configurable mechanical and degradable attributes. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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31. Effects of oil palm shell coarse aggregate species on high strength lightweight concrete.
- Author
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Yew MK, Bin Mahmud H, Ang BC, and Yew MC
- Subjects
- Compressive Strength, Industrial Waste, Materials Testing, Arecaceae, Construction Materials
- Abstract
The objective of this study was to investigate the effects of different species of oil palm shell (OPS) coarse aggregates on the properties of high strength lightweight concrete (HSLWC). Original and crushed OPS coarse aggregates of different species and age categories were investigated in this study. The research focused on two OPS species (dura and tenera), in which the coarse aggregates were taken from oil palm trees of the following age categories (3-5, 6-9, and 10-15 years old). The results showed that the workability and dry density of the oil palm shell concrete (OPSC) increase with an increase in age category of OPS species. The compressive strength of specimen CD3 increases significantly compared to specimen CT3 by 21.8%. The maximum achievable 28-day and 90-day compressive strength is 54 and 56 MPa, respectively, which is within the range for 10-15-year-old crushed dura OPS. The water absorption was determined to be within the range for good concrete for the different species of OPSC. In addition, the ultrasonic pulse velocity (UPV) results showed that the OPS HSLWC attain good condition at the age of 3 days.
- Published
- 2014
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32. Effect of nitric acid concentrations on synthesis and stability of maghemite nanoparticles suspension.
- Author
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Nurdin I, Johan MR, Yaacob II, and Ang BC
- Subjects
- Thermogravimetry, X-Ray Diffraction, Ferric Compounds chemistry, Nanoparticles chemistry, Nitric Acid chemistry
- Abstract
Maghemite (γ-Fe2O3) nanoparticles have been synthesized using a chemical coprecipitation method at different nitric acid concentrations as an oxidizing agent. Characterization of all samples performed by several techniques including X-ray diffraction (XRD), transmission electron microscopy (TEM), alternating gradient magnetometry (AGM), thermogravimetric analysis (TGA), dynamic light scattering (DLS), and zeta potential. The XRD patterns confirmed that the particles were maghemite. The crystallite size of all samples decreases with the increasing concentration of nitric acid. TEM observation showed that the particles have spherical morphology with narrow particle size distribution. The particles showed superparamagnetic behavior with decreased magnetization values at the increasing concentration of nitric acid. TGA measurement showed that the stability temperature decreases with the increasing concentration of nitric acid. DLS measurement showed that the hydrodynamic particle sizes decrease with the increasing concentration of nitric acid. Zeta potential values show a decrease with the increasing concentration of nitric acid. The increasing concentration of nitric acid in synthesis of maghemite nanoparticles produced smaller size particles, lower magnetization, better thermal stability, and more stable maghemite nanoparticles suspension.
- Published
- 2014
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33. The Singapore 5-fluorouracil trial: intraocular pressure outcomes at 8 years.
- Author
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Wong MH, Husain R, Ang BC, Gazzard G, Foster PJ, Htoon HM, Wong TT, Oen FT, Khaw PT, Seah SK, and Aung T
- Subjects
- Antihypertensive Agents therapeutic use, Combined Modality Therapy, Double-Blind Method, Follow-Up Studies, Glaucoma, Angle-Closure drug therapy, Glaucoma, Angle-Closure physiopathology, Glaucoma, Angle-Closure surgery, Glaucoma, Open-Angle drug therapy, Glaucoma, Open-Angle physiopathology, Glaucoma, Open-Angle surgery, Humans, Middle Aged, Proportional Hazards Models, Prospective Studies, Retrospective Studies, Risk Factors, Singapore, Tonometry, Ocular, Treatment Failure, Treatment Outcome, Visual Fields, Antimetabolites therapeutic use, Fluorouracil therapeutic use, Glaucoma, Angle-Closure therapy, Glaucoma, Open-Angle therapy, Intraocular Pressure drug effects, Trabeculectomy
- Abstract
Objective: To report the 8-year outcomes of Asian subjects who underwent trabeculectomy augmented by intraoperative 5-fluorouracil (5-FU) or placebo., Design: Retrospective review of a randomized controlled trial., Participants: Subjects with primary open-angle or angle-closure glaucoma., Methods: Study subjects were prospectively followed up for 3 years. After the last subject recruited had completed 8 years of follow-up, the charts of all subjects were reviewed to capture data from the year 3 visit onward. Kaplan-Meier survival function with Cox regression was performed to identify risk factors associated with trabeculectomy failure at 8 years., Main Outcome Measures: The primary outcome was trabeculectomy failure defined as intraocular pressure (IOP) >21 or <6 mmHg on 2 consecutive occasions after the first 6 weeks after surgery, repeat glaucoma surgery, or loss of light perception. Further end points were defined at IOP levels >17 and >14 mmHg. Secondary outcomes included IOP at 8 years and number of glaucoma medications. Complete success was defined using IOP end points ≤ 21, ≤ 17, or ≤ 14 mmHg at 8 years without medications., Results: Of the 243 enrolled subjects, 170 (70.0%) completed 8 years follow-up, 86 in the 5-FU and 84 in the placebo group. There was no significant difference in failure rates at 8 years for the failure definitions of IOP >21 mmHg (11.6% of the 5-FU group vs. 16.7% of the placebo group; P = 1.00), IOP >17 mmHg (23.3% of the 5-FU group vs. 31% of the placebo group; P = 0.78), and IOP >14 mmHg (46.5% of the 5-FU group vs. 58.3% of the placebo group; P = 0.37). Mean IOP at 8 years was 13.7 mmHg in the 5-FU versus 14.4 mmHg in the placebo group (P = 0.24). Mean number of medications was 0.65 drops in the 5-FU versus 0.93 drops in the placebo group (P = 0.06). Complete success with IOP ≤ 21 mmHg at 8 years was achieved in 48 subjects (55.8%) in the 5-FU and 33 subjects (39.3%) in the placebo group (P = 0.09). Absence of bleb microcysts at 1 year, preoperative IOP, and number of bleb needlings performed within the first year were significantly associated with failure., Conclusions: There was no significant difference in IOP between the 5-FU and the placebo group at 8 years., Financial Disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article., (Copyright © 2013 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.)
- Published
- 2013
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34. Tailoring the Catalytic Activity of Fe3O4 Nanoparticles for KNO3 Decomposition via Surface Functionalization.
- Author
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Dibdalli, Yuvaraja, Pérez, Héctor, López-Telgie, Alejandro, Vejar, Nelson, MacLeod-Carey, Desmond, Gaete, José, Abarca, Gabriel, and Morales-Verdejo, Cesar
- Subjects
IRON oxide nanoparticles ,PHYSICAL & theoretical chemistry ,CATALYTIC activity ,POTASSIUM nitrate ,TRANSMISSION electron microscopy ,PROPELLANTS - Abstract
This study investigates the synthesis, characterization, and catalytic activity of functionalized iron oxide nanoparticles for the thermal decomposition of potassium nitrate (KNO
3 ). The iron oxide nanoparticles (Fe3 O4 NPs ) were synthesized using a co-precipitation method and then functionalized with 11-Bromoundecanoic (Fe₃O₄@Br) and 11-Aminoundecanoic acids (Fe₃O₄@NH₂) by chemical route. The functionalized nanoparticles were characterized using Transmission electron microscopy (TEM), Thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FT-IR), and vibrating sample magnetometry (VSM). The characterization results revealed that the nanoparticles have a uniform size of approximately 8.3 nm, exhibit superparamagnetic behavior, and are successfully functionalized. To compare short and long-chain ligands, we included our previously reported quaternary (Fe₃O₄@NR4 + ) and tertiary (Fe3 O4 @NR3 ) amine-functionalized magnetic catalysts in the catalytic studies. Among the different functionalized nanoparticles, Fe3 O4 @NR3 exhibited the most pronounced catalytic activity, significantly reducing the decomposition temperature (DT) of KNO3 to 683.2 °C compared to the other nanoparticles. This enhanced catalytic activity is attributed to the specific interaction between the Fe3 O4 @NR3 surface and KNO3 molecules. The activation energies (Ea ) for the thermal decomposition of KNO3 were calculated using the ASTM e628 method, confirming the decrease in activation energy for the Fe3 O4 @NH2 + KNO3 mixture compared to pure KNO3 . These findings demonstrate the potential of tailored surface functionalization to improve the catalytic performance of Fe3 O4 nanoparticles for KNO3 decomposition, which has potential applications in various fields such as propellants, explosives, and pyrotechnics. [ABSTRACT FROM AUTHOR]- Published
- 2025
- Full Text
- View/download PDF
35. Design, Formulation, and Evaluation of Opthalmic Multilayer Nanofiber Insert for Management of Dry Eye Disease.
- Author
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Sakpal, Darshana, Mhase, Mayur, Momin, Munira, Gharat, Sankalp, Sawarkar, Sujata, Boddu, Sai H. S., and Al-Tabakha, Moawia
- Abstract
Due to changing lifestyles, millions of people worldwide experience dry eye disease (DED). The treatment for DED primarily involves the topical use of artificial tears and anti-inflammatory eye drops. Frequent administration of conventional eye drops leads to reduced patient adherence. This study aims to improve the convenience and reduce the dosing frequency, by designing dexamethasone sodium phosphate (DSP)-loaded multilayer nanofiber inserts (MLNI) for managing DED. The drug-loaded electrospun nanofibers were sandwiched between two blank nanofiber scaffolds. The outer nanofiber scaffolds will aid mucoadhesion and lubricate the cornea to reduce the dryness. The middle layer of the insert was fabricated using chitosan(1%w/v), polyvinyl alcohol (10%w/v), and DSP (0.1%w/w), while the outer layer consisted of hyaluronic acid (0.8%w/v) and polyvinyl alcohol (10%w/v). The developed nanofibers exhibited a diameter of 125 ± 30 nm and entrapment efficiency of 95.6 ± 0.52%. The optimized nanofiber insert had a thickness of 0.48 ± 0.03 mm, porosity of 55 ± 5%, swelling index of 94.8 ± 10%, surface pH of about 6.5 ± 0.2, and folding endurance of about 245 ± 3. Ex vivo permeation studies using goat eye cornea demonstrated a sustained drug release of 85.90 ± 1.243% up to 32 h, following the Hixson–Crowell model (R
2 of 0.931). A hemocompatibility study showed compatibility of developed scaffold with blood cells. Results of HET-CAM, cell culture studies on SIRC cells, and sterility studies indicate that the developed sterile multilayered sandwich type nanofiber ocular insert is safe and effective in the delivery of DSP for management of DED. [ABSTRACT FROM AUTHOR]- Published
- 2025
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- View/download PDF
36. Case report of cytomegalovirus retinitis in an HIV-positive patient with a CD4-count nadir of 254 cells per μl.
- Author
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Ang BC and Teoh SC
- Subjects
- Adenine analogs & derivatives, Adenine therapeutic use, Administration, Oral, Adult, Alkynes, Anti-HIV Agents therapeutic use, Aqueous Humor virology, Benzoxazines therapeutic use, CD4 Lymphocyte Count, CD4-Positive T-Lymphocytes immunology, Cyclopropanes, Cytomegalovirus genetics, Cytomegalovirus Retinitis drug therapy, Cytomegalovirus Retinitis immunology, Deoxycytidine analogs & derivatives, Deoxycytidine therapeutic use, Drug Therapy, Combination, Emtricitabine, HIV Infections drug therapy, HIV Infections immunology, Humans, Male, Organophosphonates therapeutic use, Polymerase Chain Reaction, Tenofovir, Visual Acuity physiology, Cytomegalovirus Retinitis complications, HIV Infections complications
- Published
- 2012
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37. Enhancing Quality Control in the Mix Design of High-Strength Concrete Using a Capacity-Based Approach.
- Author
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Basu, Dhiman, Mushtaq, Sheikh Mayesser, Sharma, Shivani, and Tripathi, Sandesh
- Subjects
CONCRETE mixing ,FAILURE mode & effects analysis ,QUALITY control ,EARTHQUAKE resistant design ,CONCRETE fatigue - Abstract
The mix design of concrete is an important aspect that affects its strength and durability. This paper aims to revisit the existing mix design method given in IS 10262:2019 through a capacity-based approach. The approach involves identifying the possible failure modes in concrete and eliminating the undesirable ones leading to significant reduction in dispersion. This is accomplished by utilizing coarse aggregates that meet a specific minimum strength requirement or threshold (e.g., ~ 77 MPa for M95 grade of concrete), which is determined through a priori estimating the cohesion and friction angle of the concrete. The methodology to estimate the cohesion and friction angle from a single unconfined compression test is proposed based on the Mohr–Coulomb theory and using the orientation of failure plane of fractured specimen as a supplemental information from the same experiment. This paper also offers a simple and approximate test procedure to estimate the aggregate's compressive strength (~ 106 MPa in this mix design) reasonably which is essential for the capacity-based mix design. An experimental programme is also carried out to design the concrete mix using the proposed capacity-based approach. The results indicate that M95 concrete is achieved with a low standard deviation and coefficient of variation (~ 3%), falling in class of excellent quality control as per ACI 214R-11. This quality control is crucial in seismic structural design as variations in concrete strength is likely to negate the underlying principle of strong column–weak beam philosophy resulting in the triggering of undesirable shear modes of failure. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
38. A precise look at electrospinning parameters in fabricating the polymeric nanofibers: a review on synthetic and natural polymers.
- Author
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Bayat, Fereshteh, Hashtrodylar, Yasaman, Karimi, Hanieh, Mehryab, Fatemeh, and Haeri, Azadeh
- Published
- 2024
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39. Electrospun silver chloride-loaded PVA nanofibers as a potential antibacterial and electroconductive scaffold for the management of wound infection and healing.
- Author
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Abazari, Morteza, Sharafi, Ali, Hassan, Maryam, Moghimi, Hamid Reza, Andalib, Sina, and Ghaffari, Azadeh
- Subjects
THERMOGRAVIMETRY ,POLYVINYL alcohol ,SILVER chloride ,SODIUM nitrate ,SCANNING electron microscopy - Abstract
Recently, designing and fabricating effectual wound dressings have gained a great deal of interest for the proper management of wound infections and biofilms. The present study is focused on the fabricating and characterizing silver chloride-loaded polyvinyl alcohol nanofibers as antibacterial and conductive wound dressing scaffold by electrospinning technique. Polyvinyl alcohol was subjected to the electrospinning process, and silver chloride was incorporated within PVA nanofibers via in situ reaction between silver nitrate and sodium chloride during the fiber-forming process. The obtained silver-free and silver chloride-containing nanofibers were characterized by different techniques, including scanning electron microscopy (SEM), Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), thermal gravimetric analysis (DSC and TGA), etc. The gravimetric method and tensile testing were used to determine the porosity and mechanical properties of the fabricated nanofibers. The nanofiber's in vitro degradation, swelling, and water retention properties were assessed, and their drug loading and release profiles were evaluated by the atomic absorption spectrometry (AAS) method. The wound healing characteristics of the obtained nanofibers, such as antibacterial activity, hemocompatibility, electrical conductivity, and cytotoxicity were evaluated in vitro. The results of this study confirmed that the silver chloride-containing nanofibers exhibit desired physicochemical, morphological, and mechanical properties and could be considered as a potential wound dressing for the management of infectious wounds. On the other hand, the obtained nanofibers showed higher hemocompatibility (less than 5% hemolysis ratio) and cell viability (over 80% after 48 h) as well as appropriate antibacterial activity against two representative strains of Gram-positive and Gram-negative bacteria. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
40. Simulation performance of inkjet-printed polyaniline–graphene oxide nanocomposite based gas sensor.
- Author
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Arularasan, Arivarasi, Venkataramani, Kiruthika, Venkatachalam Rajarajan, Balaji, Jeyaraman, Sathyasree, Kumar, Anand, and Kannan, Ramani
- Subjects
GAS detectors ,WASTE gases ,INDUSTRIAL gases ,CONDUCTING polymers ,INDUSTRIAL wastes ,POLYANILINES - Abstract
Detecting dangerous gases is crucial for protecting human and environmental health. Industrial waste gases like CO, NO2, H2S, and NH3 have long been a concern for investigators. Gas sensors, particularly chemi-resistive sensors, are widely used in industries to detect leaks and manage gas concentrations. Traditional gas sensors have utilized semiconducting oxides such as SnO2, ZnO, Fe2O3, and In2O3. However, conducting polymers, like polyaniline, have emerged as ideal materials for gas sensors due to their ability to operate at room temperature. This paper investigates the simulation performance of gas sensors based on a polyaniline-graphene oxide (PANI/GO) nanocomposite, fabricated using inkjet printing. The study analyzes various factors that affect sensor performance, including responsivity, sensitivity, gas concentration, response time, and recovery time, using Atomistix ToolKit. The results show that the PANI/GO nanocomposite-based gas sensor outperforms existing nanomaterial-based sensors, demonstrating its potential as an effective candidate for detecting dangerous gases. To improve the behavior of the gas sensor, the chemicals are first synthesized, and then the composite is printed using inkjet technology. The simulation using Atomistix ToolKit allows for a comprehensive analysis of the sensor's performance, considering factors like responsivity, sensitivity, gas concentration, response time, and recovery time. Compared to existing nanomaterial-based sensors, the proposed gas sensor proves to be effective. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
41. Changes in IOL power after laser peripheral iridotomy based on multivariate analysis.
- Author
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Wang, Xinyu, Xue, Shasha, Yu, Zhiying, Wang, Fenglei, Wang, Licun, Wang, Yunxiao, and Wang, Ling
- Subjects
PEARSON correlation (Statistics) ,LINEAR statistical models ,FISHER exact test ,REGRESSION analysis ,MATHEMATICAL models - Abstract
Background: This study aimed to investigate the effect of laser peripheral iridotomy (LPI) on intraocular lens (IOL) power in patients with primary angle closure disease (PACD), and to construct mathematical models to assess changes in IOL power. Methods: This study included 58 eyes of PACD patients. IOL Master700 was used to analyze and compare the changes of IOL power and ocular related parameters in each formula before and after LPI. The number of cases with IOL power changes greater than 0.5 diopters (D) in each group were counted and significant differences were analyzed using Fisher's exact test. Pearson's linear correlation analysis was used to ascertain the relationship between IOL power changes and ocular parameter changes to establish mathematical models. Results: No significant difference was found in calculated IOL power changes before and after LPI in each group. There was significant difference in the number of cases with IOL change values greater than 0.5D between the primary angle closure glaucoma (PACG) and the other two groups for each formula. IOL power changes were mainly associated with △K and △AL. Mathematical models of IOL power changes after LPI were constructed based on linear regression analysis.(PAC group: △IOL
Haigis =0.026–2.950×△AL-1.414×△K, △IOLHoffer Q =-3.578×△AL-1.412×△K, △IOLSRK/T =-3.152×△AL-1.114×△K, △IOLHolladay 1 =-3.405×△AL-1.291×△K, △IOLHolladay 2 =-3.467×△AL-1.483×△K, △IOLBUII =-3.185×△AL-1.301×△K; PACG group:△IOLHaigis =-1.632×△K, △IOLHoffer Q =-3.770×△AL-1.434×△K, △IOLSRK/T =-3.427×△AL-1.102×△K, △IOLHolladay 1 =-3.625×△AL-1.278×△K, △IOLHolladay 2 =-4.764×△AL-1.272×△K, △IOLBUII =-4.935×△AL-1.304×△K). Conclusions: LPI will cause changes in some ocular parameters in patients with PACD, with great effects on IOL power calculations was observed in patients with PACG. Mathematical models based on multivariate analysis hold promise for predicting IOL power changes subsequent to LPI. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
42. Potential of eNose Technology for Monitoring Biological CO2 Conversion Processes.
- Author
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Awais, Muhammad, Naqvi, Syed Muhammad Zaigham Abbas, Khan, Sami Ullah, Khan, M. Ijaz, Abdullaev, Sherzod, Wu, Junfeng, Zhang, Wei, and Hu, Jiandong
- Abstract
Electronic nose (eNose) is a modern bioelectronic sensor for monitoring biological processes that convert CO
2 into value-added products, such as products formed during photosynthesis and microbial fermentation. eNose technology uses an array of sensors to detect and quantify gases, including CO2 , in the air. This study briefly introduces the concept of eNose technology and potential applications thereof in monitoring CO2 conversion processes. It also provides background information on biological CO2 conversion processes. Furthermore, the working principles of eNose technology vis-à-vis gas detection are discussed along with its advantages and limitations versus traditional monitoring methods. This study also provides case studies that have used this technology for monitoring biological CO2 conversion processes. eNose-predicted measurements were observed to be completely aligned with biological parameters for R2 values of 0.864, 0.808, 0.802, and 0.948. We test eNose technology in a variety of biological settings, such as algae farms or bioreactors, to determine its effectiveness in monitoring CO2 conversion processes. We also explore the potential benefits of employing this technology vis-à-vis monitoring biological CO2 conversion processes, such as increased reaction efficiency and reduced costs versus traditional monitoring methods. Moreover, future directions and challenges of using this technology in CO2 capture and conversion have been discussed. Overall, we believe this study would contribute to developing new and innovative methods for monitoring biological CO2 conversion processes and mitigating climate change. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
43. Fabrication, characterization, and optimization of core–shell electrospun nanofibers for simultaneous sustained delivery of metformin and glibenclamide in type II diabetes treatment.
- Author
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Naghizadeh, Amir, Salehi, Mohammad Ali, and Mivehi, Leila
- Subjects
TYPE 2 diabetes ,PHARMACOKINETICS ,PATIENT compliance ,MATHEMATICAL optimization ,ELECTRIC conductivity ,METFORMIN - Abstract
In this study, we successfully fabricated and characterized core–shell electrospun nanofibers using a PCL–PEG/PCL–PEG system for the simultaneous sustained delivery of metformin and glibenclamide for the treatment of type II diabetes. The FTIR analysis confirmed the presence of the loaded drugs within the fibers, while XRD results indicated that the fibers were predominantly in the amorphous phase. FESEM micrographs revealed cylindrical fiber morphology with an average diameter ranging from 100 to 380 nm, and TEM imaging confirmed the core–shell structure. The effects of various parameters, including core/shell flow ratio, core PEG molecular weight, and shell electrical conductivity, on fiber properties and drug release kinetics were investigated. Notably, a higher shell/core flow ratio of 8:1 resulted in a 21% decrease in the total releasable drug amount ( A ∞ ) for metformin compared to a 1:1 ratio. Additionally, increasing the core PEG molecular weight from 6 to 35 kDa led to a 16% reduction in A ∞ for glibenclamide. Through mathematical modeling and optimization, the ideal formulation was identified, exhibiting an A ∞ of 4.67 mg/g and 4.19 mg/g for metformin and glibenclamide, respectively. The 60% release time (T60) for this optimized formulation was 83.28 h for metformin and 91.26 h for glibenclamide, demonstrating extended-release behavior. The comprehensive evaluations and mathematical modeling suggest that the presented core–shell drug release system outperforms fibers of the same material produced by conventional electrospinning, suggesting a promising approach for improving medication adherence in type II diabetes management. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
44. Assessing polylactic acid nanofibers with cellulose and chitosan nanocapsules loaded with chamomile extract for treating gram-negative infections.
- Author
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Asadzadeh, Fatemeh, Ghorbanzadeh, Sadegh, Poursattar Marjani, Ahmad, Gholami, Reza, Asadzadeh, Faezeh, and Lotfollahi, Lida
- Abstract
This study presents the development and characterization of a novel nanocomposite wound dressing material based on polylactic acid (PLA) nanofibers incorporating chitosan nanocapsules loaded with chamomile extract and cellulose nanoparticles. The nanofibers were fabricated using a three-step synthesis and electrospinning techniques, resulting in uniform, bead-free fibers with an average diameter of 186 ± 56 nm. Fourier-transform infrared spectroscopy confirmed the successful incorporation of all components, while tensile strength tests demonstrated improved mechanical properties by adding nanoparticles. Water contact angle measurements revealed enhanced surface wettability of the PLA-Cellulose-Chitosan complex compared to pure PLA nanofibers. In vitro biocompatibility assessments using MTT assays showed excellent cell viability and proliferation, with the optimized composite exhibiting the best performance. Scanning electron microscopy imaging confirmed robust cell adhesion and interaction with the nanofibers. The nanocomposite demonstrated significant antimicrobial activity against Escherichia coli, with a 20 mm inhibition zone observed for chamomile extract-loaded samples. Additionally, the material showed superior hemostatic ability compared to commercial gauze and high hemocompatibility. These comprehensive results indicate that the developed nanocomposite is a promising candidate for advanced wound management applications, offering a multifunctional approach to wound healing by combining antimicrobial activity, cell compatibility, and hemostatic properties. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
45. Review of design and manufacturing of superabsorbent polymers (SAPs) hydrogel for agriculture in arid areas.
- Author
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Muhammad, Maysa, Tawfic, Medhat, and Elsabbagh, Ahmed
- Subjects
SUPERABSORBENT polymers ,MANUFACTURING processes ,WATER harvesting ,SANDY soils ,PLANT nutrients - Abstract
This review aims to be a reference article on designing and manufacturing different SAP materials for use in agriculture. The structure used for the content described reveals significant progress in the agricultural sector in recent years. SAP materials to enhance sandy soil compactness, topology, and mechanical properties (swelling, water harvesting, and nutrient release). SAPs in agriculture also promote a 60–80% swelling rate, slow release of nutrients for plants to last longer, and maximum water retention. This systematic review examined methods for designing, manufacturing, and processing SAPs for their properties and impact on agriculture in arid areas and plant growth. SAP materials are designed and manufactured in three morphologies. The first is the preparation of technical processes for manufacturing SAP (hydrogel) powder. Second, SAPs are prepared by mixing the monomer solution and crosslinking agent and converting the SAP solution into fibers using an electrospinning machine and wet spinning technique. Finally, the sheet was produced using a spun lace (hydroentangling) machine that converts SAP fibers into sheets. Similarly, the production processes used a spun-bond machine that converts SAP powder into sheets and a sheet modeling machine that converts SAP fibers into SAP sheets. Furthermore, many SAP materials used for agriculture in arid areas, functional monomers, initiators, and cross-liner agents can be manufactured as powders, fibers, and sheets and have high success rates. This is demonstrated by the excellent maximum absorbent capacity, and maximum water retention of the sheets, followed by those of the fibers and powders. This is supported by the quantitative standards for SAP morphology manufacturing process cost, water absorption, and water retention time. Highlights: Characteristics of SAPs for use in agriculture. Design and manufacture of SAPs suitable for agriculture. Evaluation of SAP performance for use in agriculture. The appropriate SAP morphology should be chosen to ensure the maximum planting performance. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
46. A brief review on electrospun polymer derived carbon fibers for EMI shielding applications.
- Author
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Deeraj, B. D. S., Paul, Rhiya, and Joseph, Kuruvilla
- Subjects
CARBON-based materials ,CARBON composites ,CARBON fibers ,INFORMATION technology ,ELECTROMAGNETIC radiation ,FIBROUS composites - Abstract
The rapid growth of electronic information technology has led to an increase in electromagnetic wave radiation pollution. Therefore, it is imperative to look into shielding materials with superior electromagnetic interference (EMI) shielding capabilities. Because of its exceptional benefits, nanofibers made by electrospinning are capable of the shielding from electromagnetic radiation. This work tries to bring together the details of electrospinning, electrospun carbon and electrospun composite fibers. Furthermore, the preparation, properties and EMI shielding performance of electrospun carbon and composite fibers are presented. This article attempts to provide an overview of the advancements made in the field of carbon fibrous material prepared via electrospinning for shielding applications. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
47. An assessment of electronically captured data in the patient care enhancement system (PACES) for syndromic surveillance.
- Author
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Ang BC, Chen MI, Goh TL, Ng YY, and Fan SW
- Subjects
- Adolescent, Adult, Humans, Population Surveillance, Syndrome, Infections epidemiology, Medical Records Systems, Computerized
- Abstract
Introduction: A common approach to the surveillance of emerging infectious diseases and agents of bioterrorism is to analyse electronically captured data for disease syndromes. The Patient Care Enhancement System (PACES) is a form of electronic medical records presently in service in the Singapore Armed Forces (SAF). We assess the feasibility of PACES data for surveillance, describe time-trends, and identify methods of sub-analysis which could improve performance., Materials and Methods: Medical consults from July 2000 to June 2003 were extracted. Diagnosis codes were mapped to 7 infectious disease syndromes according to the categorisation in the Electronic Surveillance System for the Early Notification of Community-based Epidemics (ESSENCE): gastrointestinal (GI), fever (FEVER), respiratory, (RESP), coma (COMA), neurological (NEURO), dermatologic-haemorrhagic (DERMHEM) and dermatologic- infectious (DERM-INF)., Results: A total of 732,233 episodes of care were analysed. Weekly periodicity was observed, with decreased weekend consults; there were no obvious seasonal trends in any of the syndromes. RESP, FEVER and GI syndromes were common events. Sub-analyses, either by restricting to cases with a repeated consultation, or grouping the data by medical centres, could dramatically lower thresholds used to flag outbreaks., Conclusion: In spite of the level of background noise inherent in a system consisting mainly of primary care consults, sub-analysis by medical centre, or restriction to cases with repeated consults were able to yield sensitive thresholds for outbreak detection.
- Published
- 2005
48. The quest for nursing excellence.
- Author
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Ang BC
- Subjects
- Humans, Nurse Practitioners education, Quality of Health Care, Singapore, Clinical Competence standards, Nurse Practitioners organization & administration, Nurse's Role
- Published
- 2002
49. Bed rest decreases whole-body protein turnover in post-absorptive man.
- Author
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Bettany GE, Ang BC, Georgiannos SN, Halliday D, and Powell-Tuck J
- Subjects
- Absorption, Adult, Ammonia analysis, Female, Humans, Male, Nitrogen Radioisotopes pharmacokinetics, Radioactive Tracers, Urea analysis, Bed Rest, Proteins metabolism
- Abstract
1. Whole-body protein turnover was measured using the [15N]glycine tracer technique in 10 post-absorptive healthy volunteers during normal daily activities and a period of bed rest. 2. Bed rest reduced whole-body protein turnover (25%), synthesis (26%) and breakdown (25%), but short-term urinary nitrogen excretion remained unchanged.
- Published
- 1996
- Full Text
- View/download PDF
50. Lipid fuel metabolism after abdominal surgery.
- Author
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Georgiannos SN, James AH, Ang BC, Sugden MC, and Goode AW
- Subjects
- Abdomen surgery, Fatty Acids, Nonesterified metabolism, Female, Glucose administration & dosage, Glucose metabolism, Humans, Ketone Bodies metabolism, Liver metabolism, Male, Middle Aged, Postoperative Period, Lipolysis, Stress, Physiological metabolism, Surgical Procedures, Operative
- Abstract
The work investigated fuel interrelationships in surgical patients infused with saline (Group I) or glucose (Group II) (13 patients in each group) on the day of surgery and subsequently maintained solely on saline until the fifth postoperative day. Blood concentrations of non-esterified fatty acids (NEFA) and ketone bodies were markedly increased in response to surgical stress on the day of surgery only in patients who were not administered carbohydrate. Increased concentrations of lactate and glucose were observed on the day of surgery in patients infused with either saline or glucose. As both fatty acid and ketone body concentrations were decreased by glucose infusion, impaired glucose utilization immediately after surgery is not a simple consequence of increased oxidation of lipid fuels. Glucose and lactate concentrations declined after the day of surgery. Despite a progressive fall in plasma non-esterified fatty acid concentrations from the first to fifth post-operative days, blood ketone body concentrations were strikingly elevated in both groups of patients. The findings emphasize the role of the liver in post-operative fatty acid turnover.
- Published
- 1994
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