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Fabrication and transport performance characterization of chemically-doped three-branch junction graphene device

Shaharin Fadzli Abd Rahman, Kasai S, Abdul Manaf Hashim

Sains Malaysiana, 2013;42:187-192.

A graphene-based three-branch nanojunction (TBJ) device having nanowire width of 200 nm was successfully fabricated. The layer number of graphene prepared by mechanical exfoliation was determined using a simple optical contrast method which showed good agreement with theoretical value. n-type doping by Polyethylene imines (PEI) was done to control the position of Dirac point. Baking and PEI doping was found to decrease contact resistance and increase the carrier mobility. The chemically-doped TBJ graphene showed carrier mobility of 20000 cm2/Vs, which gave related mean free path of 175 nm.

Matched MeSH terms: Polyethylenes
Rapid magnetophoretic separation of microalgae

Lim JK, Chieh DC, Jalak SA, Toh PY, Yasin NH, Ng BW, et al.

Small, 2012 Jun 11;8(11):1683-92.
PMID: 22438107 DOI: 10.1002/smll.201102400

Magnetic collection of the microalgae Chlorella sp. from culture media facilitated by low-gradient magnetophoretic separation is achieved in real time. A removal efficiency as high as 99% is accomplished by binding of iron oxide nanoparticles (NPs) to microalgal cells in the presence of the cationic polyelectrolyte poly(diallyldimethylammonium chloride) (PDDA) as a binder and subsequently subjecting the mixture to a NdFeB permanent magnet with surface magnetic field ≈6000 G and magnetic field gradient <80 T m(-1) . Surface functionalization of magnetic NPs with PDDA before exposure to Chlorella sp. is proven to be more effective in promoting higher magnetophoretic removal efficiency than the conventional procedure, in which premixing of microalgal cells with binder is carried out before the addition of NPs. Rodlike NPs are a superior candidate for enhancing the magnetophoretic separation compared to spherical NPs due to their stable magnetic moment that originates from shape anisotropy and the tendency to form large NP aggregates. Cell chaining is observed for nanorod-tagged Chlorella sp. which eventually fosters the formation of elongated cell clusters.

Matched MeSH terms: Polyethylenes/chemistry
The impact of surface and geometry on coefficient of friction of artificial hip joints

Choudhury D, Vrbka M, Mamat AB, Stavness I, Roy CK, Mootanah R, et al.

J Mech Behav Biomed Mater, 2017 08;72:192-199.
PMID: 28500998 DOI: 10.1016/j.jmbbm.2017.05.011

Coefficient of friction (COF) tests were conducted on 28-mm and 36-mm-diameter hip joint prostheses for four different material combinations, with or without the presence of Ultra High Molecular Weight Polyethylene (UHMWPE) particles using a novel pendulum hip simulator. The effects of three micro dimpled arrays on femoral head against a polyethylene and a metallic cup were also investigated. Clearance played a vital role in the COF of ceramic on polyethylene and ceramic on ceramic artificial hip joints. Micro dimpled metallic femoral heads yielded higher COF against a polyethylene cup; however, with metal on metal prostheses the dimpled arrays significantly reduced the COF. In situ images revealed evidence that the dimple arrays enhanced film formation, which was the main mechanism that contributed to reduced friction.

Matched MeSH terms: Polyethylenes/analysis*
U.S. plastic waste exports: A state-by-state analysis pre- and post-China import ban

Bourtsalas ACT, Yepes IM, Tian Y

J Environ Manage, 2023 Oct 15;344:118604.
PMID: 37459814 DOI: 10.1016/j.jenvman.2023.118604

This study analyzes the regional implications of China's 2017 import ban on plastic waste by examining U.S. census data. A statistically significant decrease in total U.S. plastic waste exports was found, dropping from about 1.4 million tons to 0.6 million tons in the post-ban period. California remained the top exporter, throughout both pre- and post-ban periods, while South Carolina exhibited the highest per capita exports. Malaysia emerged as the largest importer of U.S. plastic waste, followed by Vietnam, Indonesia, and Thailand. The ban also led to a change in the composition of the exported plastic waste. Ethylene polymers increased from 32.6% of total exports in the pre-ban period to 46.9% in the post-ban period. Other plastics (vinyl chloride polymers, styrene polymers, and for plastics not elsewhere specified or included) decreased from 67.4% of total exports in the pre-ban period to 53.1% in the post-ban period. Moreover, we found that exporting plastic waste has significant environmental and human health impacts. For example, the Global Warming Potential (GWP) decreased from 20 million tons CO2-eq in the scenario where 100% of plastics are exported, or 25 million tons exported from the U.S. since 2002, to -11.1 million tons CO2-eq in the scenario where 100% of plastics are treated domestically. Transportation exacerbates these impacts for exported waste scenarios, increasing to 5.4 million tons CO2-eq when plastics are exported by ship while decreasing to 0.9 million tons CO2-eq for domestic treatment. Although exporting plastic waste is initially cost-effective, our study highlights that investing in domestic waste management can yield significant long-term benefits, considering the environmental and public health impacts. Therefore, it is crucial to prioritize context-specific solutions to address the challenges of the evolving global plastic waste landscape.

Matched MeSH terms: Polyethylenes
Fulltext Mechanical, rheological, and bioactivity properties of ultra high-molecular-weight polyethylene bioactive composites containing polyethylene glycol and hydroxyapatite

Ahmad M, Uzir Wahit M, Abdul Kadir MR, Mohd Dahlan KZ

ScientificWorldJournal, 2012;2012:474851.
PMID: 22666129 DOI: 10.1100/2012/474851

Ultrahigh-molecular-weight polyethylene/high-density polyethylene (UHMWPE/HDPE) blends prepared using polyethylene glycol PEG as the processing aid and hydroxyapatite (HA) as the reinforcing filler were found to be highly processable using conventional melt blending technique. It was demonstrated that PEG reduced the melt viscosity of UHMWPE/HDPE blend significantly, thus improving the extrudability. The mechanical and bioactive properties were improved with incorporation of HA. Inclusion of HA from 10 to 50 phr resulted in a progressive increase in flexural strength and modulus of the composites. The strength increment is due to the improvement on surface contact between the irregular shape of HA and polymer matrix by formation of mechanical interlock. The HA particles were homogenously distributed even at higher percentage showed improvement in wetting ability between the polymer matrix and HA. The inclusion of HA enhanced the bioactivity properties of the composite by the formation of calcium phosphate (Ca-P) precipitates on the composite surface as proven from SEM and XRD analysis.

Matched MeSH terms: Polyethylenes/pharmacology; Polyethylenes/chemistry*
Mechanical properties of HDPE/UHMWPE blends: effect of filler loading and filler treatment

Lai KL, Roziyanna A, Ogunniyi DS, Zainal AM, Azlan AA

Med J Malaysia, 2004 May;59 Suppl B:61-2.
PMID: 15468819

Various blend ratios of high-density polyethylene (HDPE) and ultra high molecular weight polyethylene (UHMWPE) were prepared with the objective of determining their suitability as biomaterials. In the unfilled state, a blend of 50/50 (HDPE/UHMWPE) ratio by weight was found to yield optimum properties in terms of processability and mechanical properties. Hydroxyapatite (HA) was compounded with the optimum blend ratio. The effects of HA loading, varied from 0 to 50wt% for both filled and unfilled blends were tested for mechanical properties. It was found that the inclusion of HA in the blend led to a remarkable improvement of mechanical properties compared to the unfilled blend. In order to improve the bonding between the polymer blend and the filler, the HA used was chemically treated with a coupling agent known as 3-(trimethoxysiyl) propyl methacrylate and the treated HA was mixed into the blend. The effect of mixing the blend with silane-treated HA also led to an overall improvement of mechanical properties.

Matched MeSH terms: Polyethylenes/analysis; Polyethylenes/chemical synthesis*
Effects of microwave on drug release property of poly(methyl vinyl ether-co-maleic acid) matrix

Wong TW, Wahab S, Anthony Y

Drug Dev Ind Pharm, 2007 Jul;33(7):737-46.
PMID: 17654022

The drug release behavior of beads made of poly(methyl vinyl ether-co-maleic acid) was investigated with respect to the influence of microwave irradiation. The beads were prepared by an extrusion method with sodium diclofenac as a model water-soluble drug. The beads were subjected to microwave irradiation at 80 W for 5 and 20 min, and at 300 W for 1 min 20 s and 5 min 20 s. The profiles of drug dissolution, drug content, drug-polymer interaction, and polymer-polymer interaction were determined by using dissolution testing, drug content assay, differential scanning calorimetry, and Fourier transform infra-red spectroscopy. Keeping the level of supplied irradiation energy identical, treatment of beads by microwave at varying intensities of irradiation did not bring about similar drug release profiles. The extent and rate of drug released from beads were markedly enhanced through treating the samples by microwave at 80 W as a result of loss of polymer-polymer interaction via the (CH(2))(n) moiety, but decreased upon treating the beads by microwave at 300 W following polymer-polymer interaction via the O-H, COOH, and COO(-) moieties as well as drug-polymer interaction via the N-H, O-H, COO(-), and C-O moieties. The beads treated by microwave at 300 W exhibited a higher level of drug release retardation capacity than those that were treated by microwave at 80 W in spite of polymer-polymer interaction via the (CH(2))(n) moiety was similarly reduced in the matrix. The mechanism of drug release of both microwave-treated and untreated beads tended to follow zero order kinetics. The drug release was markedly governed by the state of polymer relaxation of the matrix and was in turn affected by the state of polymer-polymer and/or drug-polymer interaction in beads.

Matched MeSH terms: Polyethylenes/radiation effects; Polyethylenes/chemistry*
Drug release responses of zinc ion crosslinked poly(methyl vinyl ether-co-maleic acid) matrix towards microwave

Wong TW, Wahab S, Anthony Y

Int J Pharm, 2008 Jun 5;357(1-2):154-63.
PMID: 18329203 DOI: 10.1016/j.ijpharm.2008.01.047

The drug release characteristics of beads made of poly(methyl vinyl ether-co-maleic acid) using Zn2+ as the crosslinking agent were investigated with respect to the influence of microwave irradiation. The beads were prepared by an extrusion method with sodium diclofenac as a model water-soluble drug. They were subjected to microwave irradiation at 80W for 5 and 20 min, and at 300W for 1 min 20s and 5 min 20s. The profiles of drug dissolution, drug content, drug-polymer interaction and polymer-polymer interaction were determined by dissolution testing, drug content assay, differential scanning calorimetry and Fourier transform infrared spectroscopy. Treatment of beads by microwave at varying intensities of irradiation can aid to retard the drug release with a greater reduction extent through treating the beads for a longer duration of irradiation. The treatment of beads by microwave induced the formation of multiple polymeric domains of great strength and extent of polymer-polymer and drug-polymer interaction. The release of drug from beads was retarded via the interplay of O-H, N-H, C-H, (CH2)n and C-O functional groups of these domains, and was mainly governed by the state of polymer relaxation of the matrix unlike that of the untreated beads of which the release of drug was effected via drug diffusion and polymer relaxation. In comparison to Ca2+ crosslinked matrix which exhibited inconsistent drug release retardation behavior under the influence of microwave, the extent and rate of drug released from the Zn2+ crosslinked beads were greatly reduced by microwave and the release of drug from these beads was consistently retarded in response to both high and low intensity microwaves.

Matched MeSH terms: Polyethylenes/radiation effects*; Polyethylenes/chemistry*
Biophysical characterization of layer-by-layer synthesis of aptamer-drug microparticles for enhanced cell targeting

Tan KX, Danquah MK, Sidhu A, Lau SY, Ongkudon CM

Biotechnol Prog, 2018 01;34(1):249-261.
PMID: 28699244 DOI: 10.1002/btpr.2524

Targeted delivery of drug molecules to specific cells in mammalian systems demonstrates a great potential to enhance the efficacy of current pharmaceutical therapies. Conventional strategies for pharmaceutical delivery are often associated with poor therapeutic indices and high systemic cytotoxicity, and this result in poor disease suppression, low surviving rates, and potential contraindication of drug formulation. The emergence of aptamers has elicited new research interests into enhanced targeted drug delivery due to their unique characteristics as targeting elements. Aptamers can be engineered to bind to their cognate cellular targets with high affinity and specificity, and this is important to navigate active drug molecules and deliver sufficient dosage to targeted malignant cells. However, the targeting performance of aptamers can be impacted by several factors including endonuclease-mediated degradation, rapid renal filtration, biochemical complexation, and cell membrane electrostatic repulsion. This has subsequently led to the development of smart aptamer-immobilized biopolymer systems as delivery vehicles for controlled and sustained drug release to specific cells at effective therapeutic dosage and minimal systemic cytotoxicity. This article reports the synthesis and in vitro characterization of a novel multi-layer co-polymeric targeted drug delivery system based on drug-loaded PLGA-Aptamer-PEI (DPAP) formulation with a stage-wise delivery mechanism. A thrombin-specific DNA aptamer was used to develop the DPAP system while Bovine Serum Albumin (BSA) was used as a biopharmaceutical drug in the synthesis process by ultrasonication. Biophysical characterization of the DPAP system showed a spherical shaped particulate formulation with a unimodal particle size distribution of average size ∼0.685 µm and a zeta potential of +0.82 mV. The DPAP formulation showed a high encapsulation efficiency of 89.4 ± 3.6%, a loading capacity of 17.89 ± 0.72 mg BSA protein/100 mg PLGA polymeric particles, low cytotoxicity and a controlled drug release characteristics in 43 days. The results demonstrate a great promise in the development of DPAP formulation for enhanced in vivo cell targeting. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 34:249-261, 2018.

Matched MeSH terms: Polyethylenes/therapeutic use; Polyethylenes/chemistry
Fulltext Recovery of a Bacteriocin-Like Inhibitory Substance from Lactobacillus bulgaricus FTDC 1211 Using Polyethylene-Glycol Impregnated Amberlite XAD-4 Resins System

Abdul Aziz NFH, Abbasiliasi S, Ng ZJ, Abu Zarin M, Oslan SN, Tan JS, et al.

Molecules, 2020 Nov 16;25(22).
PMID: 33207534 DOI: 10.3390/molecules25225332

Lactobacillus bulgaricus is a LAB strain which is capable of producing bacteriocin substances to inhibit Staphylococcus aureus. The aim of this study was to purify a bacteriocin-like inhibitory substance (BLIS) produced by L. bulgaricus FTDC 1211 using an aqueous impregnated resins system consisting of polyethylene-glycol (PEG) impregnated on Amberlite XAD4. Important parameters influencing on purification of BLIS, such as the molecular weight and concentration of PEG, the concentration and pH of sodium citrate and the concentration of sodium chloride, were optimized using a response surface methodology. Under optimum conditions of 11% (w/w) of PEG 4000 impregnated Amberlite XAD4 resins and 2% (w/w) of sodium citrate at pH 6, the maximum purification factor (3.26) and recovery yield (82.69% ± 0.06) were obtained. These results demonstrate that AIRS could be used as an alternate purification system in the primary recovery step.

Matched MeSH terms: Polyethylenes
Dry sliding wear behaviour of talc-reinforced UHMWPE composite for implant application

Chang BP, Hazizan Md Akil, Ramdziah bt Md Nasir

Sains Malaysiana, 2015;44:819-825.

As of today, ultra-high molecular weight polyethylene (UHMWPE) is a thermoplastic material normally used as bearing
components for human joint replacements. However, formation of wear debris from UHMWPE after certain service
periods may cause adverse effects which remain as unresolved issues. In this study, mechanical and dry sliding wear
properties of UHMWPE reinforced with different loading of talc particles were investigated. The wear test was carried
out using Ducom TR-20 pin-on-disc tester at different pressure velocity (pv) factors under dry sliding conditions. The
worn surfaces and transfer films of pure UHMWPE and talc/UHMWPE composites were observed under scanning electron
microscope (SEM). The experimental results showed that the microhardness increased with the increase of talc loadings
in UHMWPE. The 20 wt. % talc/UHMWPE composites showed a 17% increment in microhardness as compared with pure
UHMWPE. The dry sliding wear behaviour of UHMWPE was also improved upon the reinforcement of talc. The wear rate
of UHMWPE decreased after incorporation of talc particles. The coefficient of friction (COF) increased slightly under low
pv conditions. At high pv conditions, the COF decreased in values with increasing talc loadings. The improvement in
wear behaviour may be attributed to the increase in load-carrying capacity and surface hardness of the talc/UHMWPE
composites. SEM micrographs on worn surfaces showed that plastic deformation and grooving wear were dominant for
UHMWPE. The plastic deformation and grooving wear were reduced upon the reinforcement of talc particles. The talc/
UHMWPE composites produced smoother and uniform transfer films as compared to pure UHMWPE.

Matched MeSH terms: Polyethylenes
Synthesis of linear low-density polyethylene-g-poly (acrylic acid)-co-starch/organo-montmorillonite hydrogel composite as an adsorbent for removal of Pb(ΙΙ) from aqueous solutions

Irani M, Ismail H, Ahmad Z, Fan M

J Environ Sci (China), 2015 Jan 1;27:9-20.
PMID: 25597658 DOI: 10.1016/j.jes.2014.05.049

The purpose of this work is to remove Pb(II) from the aqueous solution using a type of hydrogel composite. A hydrogel composite consisting of waste linear low density polyethylene, acrylic acid, starch, and organo-montmorillonite was prepared through emulsion polymerization method. Fourier transform infrared spectroscopy (FTIR), Solid carbon nuclear magnetic resonance spectroscopy (CNMR)), silicon(-29) nuclear magnetic resonance spectroscopy (Si NMR)), and X-ray diffraction spectroscope ((XRD) were applied to characterize the hydrogel composite. The hydrogel composite was then employed as an adsorbent for the removal of Pb(II) from the aqueous solution. The Pb(II)-loaded hydrogel composite was characterized using Fourier transform infrared spectroscopy (FTIR)), scanning electron microscopy (SEM)), and X-ray photoelectron spectroscopy ((XPS)). From XPS results, it was found that the carboxyl and hydroxyl groups of the hydrogel composite participated in the removal of Pb(II). Kinetic studies indicated that the adsorption of Pb(II) followed the pseudo-second-order equation. It was also found that the Langmuir model described the adsorption isotherm better than the Freundlich isotherm. The maximum removal capacity of the hydrogel composite for Pb(II) ions was 430mg/g. Thus, the waste linear low-density polyethylene-g-poly (acrylic acid)-co-starch/organo-montmorillonite hydrogel composite could be a promising Pb(II) adsorbent.

Matched MeSH terms: Polyethylenes/chemistry*
Fulltext Process Optimization of Ultra-High Molecular Weight Polyethylene/Cellulose Nanofiber Bionanocomposites in Triple Screw Kneading Extruder by Response Surface Methodology

Sharip NS, Ariffin H, Andou Y, Shirosaki Y, Bahrin EK, Jawaid M, et al.

Molecules, 2020 Sep 30;25(19).
PMID: 33008017 DOI: 10.3390/molecules25194498

Incorporation of nanocellulose could improve wear resistance of ultra-high molecular weight polyethylene (UHMWPE) for an artificial joint application. Yet, the extremely high melt viscosity of the polymer may constrict the mixing, leading to fillers agglomeration and poor mechanical properties. This study optimized the processing condition of UHMWPE/cellulose nanofiber (CNF) bionanocomposite fabrication in triple screw kneading extruder by using response surface methodology (RSM). The effect of the process parameters-temperature (150-190 °C), rotational speed (30-60 rpm), and mixing time (30-45 min)-on mechanical properties of the bionanocomposites was investigated. Homogenous filler distribution, as confirmed by scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) analysis, was obtained through the optimal processing condition of 150 °C, 60 rpm, and 45 min. The UHMWPE/CNF bionanocomposites exhibited improved mechanical properties in terms of Young's and flexural modulus by 11% and 19%, respectively, as compared to neat UHMWPE. An insignificant effect was observed when maleic anhydride-grafted-polyethylene (MAPE) was added as compatibilizer. The obtained results proved that homogenous compounding of high melt viscosity UHMWPE with CNF was feasible by optimizing the melt blending processing condition in triple screw kneading extruder, which resulted in improved stiffness, a contributing factor for wear resistance.

Matched MeSH terms: Polyethylenes/chemistry*
Polyelectrolyte multi-layers assembly of SiCHA nanopowders and collagen type I on aminolysed PLA films to enhance cell-material interactions

Baba Ismail YM, Ferreira AM, Bretcanu O, Dalgarno K, El Haj AJ

Colloids Surf B Biointerfaces, 2017 Nov 01;159:445-453.
PMID: 28837894 DOI: 10.1016/j.colsurfb.2017.07.086

This paper presents a new approach in assembling bone extracellular matrix components onto PLA films, and investigates the most favourable environment which can be created using the technique for cell-material interactions. Poly (lactic acid) (PLA) films were chemically modified by covalently binding the poly(ethylene imine) (PEI) as to prepare the substrate for immobilization of polyelectrolyte multilayers (PEMs) coating. Negatively charged polyelectrolyte consists of well-dispersed silicon-carbonated hydroxyapatite (SiCHA) nanopowders in hyaluronic acid (Hya) was deposited onto the modified PLA films followed by SiCHA in collagen type I as the positively charged polyelectrolyte. The outermost layer was finally cross-linked by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrocholoride and N-hydroxysulfosuccinimide sodium salt (EDC/NHS) solutions. The physicochemical features of the coated PLA films were monitored via X-ray Photoelectron Spectroscopy (XPS) and Atomic Force Microscope (AFM). The amounts of calcium and collagen deposited on the surface were qualitatively and quantitatively determined. The surface characterizations suggested that 5-BL has the optimum surface roughness and highest amounts of calcium and collagen depositions among tested films. In vitro human mesenchymal stem cells (hMSCs) cultured on the coated PLA films confirmed that the coating materials greatly improved cell attachment and survival compared to unmodified PLA films. The cell viability, cell proliferation and Alkaline Phosphatase (ALP) expression on 5-BL were found to be the most favourable of the tested films. Hence, this newly developed coating materials assembly could contribute to the improvement of the bioactivity of polymeric materials and structures aimed to bone tissue engineering applications.

Matched MeSH terms: Polyethylenes/chemistry
Fulltext Role of Sintering Temperature in Production of Nepheline Ceramics-Based Geopolymer with Addition of Ultra-High Molecular Weight Polyethylene

Ahmad R, Abdullah MMAB, Ibrahim WMW, Hussin K, Ahmad Zaidi FH, Chaiprapa J, et al.

Materials (Basel), 2021 Feb 25;14(5).
PMID: 33669116 DOI: 10.3390/ma14051077

The primary motivation of developing ceramic materials using geopolymer method is to minimize the reliance on high sintering temperatures. The ultra-high molecular weight polyethylene (UHMWPE) was added as binder and reinforces the nepheline ceramics based geopolymer. The samples were sintered at 900 °C, 1000 °C, 1100 °C, and 1200 °C to elucidate the influence of sintering on the physical and microstructural properties. The results indicated that a maximum flexural strength of 92 MPa is attainable once the samples are used to be sintered at 1200 °C. It was also determined that the density, porosity, volumetric shrinkage, and water absorption of the samples also affected by the sintering due to the change of microstructure and crystallinity. The IR spectra reveal that the band at around 1400 cm-1 becomes weak, indicating that sodium carbonate decomposed and began to react with the silica and alumina released from gels to form nepheline phases. The sintering process influence in the development of the final microstructure thus improving the properties of the ceramic materials.

Matched MeSH terms: Polyethylenes
Fulltext Melt- vs. Non-Melt Blending of Complexly Processable Ultra-High Molecular Weight Polyethylene/Cellulose Nanofiber Bionanocomposite

Sharip NS, Ariffin H, Yasim-Anuar TAT, Andou Y, Shirosaki Y, Jawaid M, et al.

Polymers (Basel), 2021 Jan 27;13(3).
PMID: 33513876 DOI: 10.3390/polym13030404

The major hurdle in melt-processing of ultra-high molecular weight polyethylene (UHMWPE) nanocomposite lies on the high melt viscosity of the UHMWPE, which may contribute to poor dispersion and distribution of the nanofiller. In this study, UHMWPE/cellulose nanofiber (UHMWPE/CNF) bionanocomposites were prepared by two different blending methods: (i) melt blending at 150 °C in a triple screw kneading extruder, and (ii) non-melt blending by ethanol mixing at room temperature. Results showed that melt-processing of UHMWPE without CNF (MB-UHMWPE/0) exhibited an increment in yield strength and Young's modulus by 15% and 25%, respectively, compared to the Neat-UHMWPE. Tensile strength was however reduced by almost half. Ethanol mixed sample without CNF (EM-UHMWPE/0) on the other hand showed slight decrement in all mechanical properties tested. At 0.5% CNF inclusion, the mechanical properties of melt-blended bionanocomposites (MB-UHMWPE/0.5) were improved as compared to Neat-UHMWPE. It was also found that the yield strength, elongation at break, Young's modulus, toughness and crystallinity of MB-UHMWPE/0.5 were higher by 28%, 61%, 47%, 45% and 11%, respectively, as compared to the ethanol mixing sample (EM-UHMWPE/0.5). Despite the reduction in tensile strength of MB-UHMWPE/0.5, the value i.e., 28.4 ± 1.0 MPa surpassed the minimum requirement of standard specification for fabricated UHMWPE in surgical implant application. Overall, melt-blending processing is more suitable for the preparation of UHMWPE/CNF bionanocomposites as exhibited by their characteristics presented herein. A better mechanical interlocking between UHMWPE and CNF at high temperature mixing with kneading was evident through FE-SEM observation, explains the higher mechanical properties of MB-UHMWPE/0.5 as compared to EM-UHMWPE/0.5.

Matched MeSH terms: Polyethylenes
Fulltext Determination of radon activity concentration in water using liquid scintillation counting technique

Zaini Hamzah, Ahmad Saat, Mohammed Kassim

Journal of Nuclear and Related Technologies, 2011;2011(1):33-38.
MyJurnal

Many studies were carried out throughout the world on radon measurement in water especially drinking water for it can cause problem to human health. This study is an attempt to measure the level of radon present in water collect from rivers and lakes. Data gathered from this study provides important information about radiation levels in water at selected sites, because radon gas is the largest contributor to natural radioactive radiation exposure to humans. Exposure to radon gas can cause lung cancer. Liquid scintillation counting (LSC) has been applied to determine the activity concentration of radon ( 222 Rn) in water. Water samples were collected from, ex-mining lake in Perak, Sok River in Kelantan, Tembeling River in Pahang. Water samples were prepared in polyethylene bottles mixed with liquid scintillator and stored for 3 weeks to allow 222 Rn and its progeny to reach the equilibrium, and the activity concentrations ranged from 0.24-1.27 Bq/L, and 0.029 – 0.155 Bq/L for radon and radium respectively.

Matched MeSH terms: Polyethylenes
Fulltext Thermoregulation and golden hour practices in extremely preterm infants: an international survey

Jani P, Mishra U, Buchmayer J, Walker K, Gözen D, Maheshwari R, et al.

Pediatr Res, 2023 May;93(6):1701-1709.
PMID: 36075989 DOI: 10.1038/s41390-022-02297-0

BACKGROUND: Are thermoregulation and golden hour practices in extremely preterm (EP) infants comparable across the world? This study aims to describe these practices for EP infants based on the neonatal intensive care unit's (NICUs) geographic region, country's income status and the lowest gestational age (GA) of infants resuscitated.
METHODS: The Director of each NICU was requested to complete the e-questionnaire between February 2019 and August 2021.
RESULTS: We received 848 responses, from all geographic regions and resource settings. Variations in most thermoregulation and golden hour practices were observed. Using a polyethylene plastic wrap, commencing humidity within 60 min of admission, and having local protocols were the most consistent practices (>75%). The odds for the following practices differed in NICUs resuscitating infants from 22 to 23 weeks GA compared to those resuscitating from 24 to 25 weeks: respiratory support during resuscitation and transport, use of polyethylene plastic wrap and servo-control mode, commencing ambient humidity >80% and presence of local protocols.
CONCLUSION: Evidence-based practices on thermoregulation and golden hour stabilisation differed based on the unit's region, country's income status and the lowest GA of infants resuscitated. Future efforts should address reducing variation in practice and aligning practices with international guidelines.
IMPACT: A wide variation in thermoregulation and golden hour practices exists depending on the income status, geographic region and lowest gestation age of infants resuscitated. Using a polyethylene plastic wrap, commencing humidity within 60 min of admission and having local protocols were the most consistent practices. This study provides a comprehensive description of thermoregulation and golden hour practices to allow a global comparison in the delivery of best evidence-based practice. The findings of this survey highlight a need for reducing variation in practice and aligning practices with international guidelines for a comparable health care delivery.

Matched MeSH terms: Polyethylenes
Directed assembly of bifunctional silica-iron oxide nanocomposite with open shell structure

Che HX, Yeap SP, Osman MS, Ahmad AL, Lim J

ACS Appl Mater Interfaces, 2014 Oct 8;6(19):16508-18.
PMID: 25198872 DOI: 10.1021/am5050949

The synthesis of nanocomposite with controlled surface morphology plays a key role for pollutant removal from aqueous environments. The influence of the molecular size of the polyelectrolyte in synthesizing silica-iron oxide core-shell nanocomposite with open shell structure was investigated by using dynamic light scattering, atomic force microscopy, and quartz crystal microbalance with dissipation (QCM-D). Here, poly(diallydimethylammonium chloride) (PDDA) was used to promote the attachment of iron oxide nanoparticles (IONPs) onto the silica surface to assemble a nanocomposite with magnetic and catalytic bifunctionality. High molecular weight PDDA tended to adsorb on silica colloid, forming a more extended conformation layer than low molecular weight PDDA. Subsequent attachment of IONPs onto this extended PDDA layer was more randomly distributed, forming isolated islands with open space between them. By taking amoxicillin, an antibiotic commonly found in pharmaceutical waste, as the model system, better removal was observed for silica-iron oxide nanocomposite with a more extended open shell structure.

Matched MeSH terms: Polyethylenes/chemistry
Hospital Universiti Sains Malaysia experience in orbital floor reconstruction: autogenous graft versus Medpor

Wajih WA, Shaharuddin B, Razak NH

J Oral Maxillofac Surg, 2011 Jun;69(6):1740-4.
PMID: 21272979 DOI: 10.1016/j.joms.2010.07.053

A normally restored orbital structure after reconstructive surgery would accelerate the return of orbital function. The aim of the present study was to compare the outcomes of 2 orbital implants: autogenous grafts and porous polyethylene (Medpor).

Matched MeSH terms: Polyethylenes*

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