Displaying publications 81 - 100 of 219 in total

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  1. Local exhaust ventilation: past, present, and future
    Nor Halim Hasan, Said, M.R., Leman, A.M.
    Journal of Occupational Safety and Health, 2013;10(1):9-26.
    MyJurnal
    Engineering control is a method of controlling the risk of exposure to contaminants. Health effects to industrial workers are more severe whilst high exposure and time exposed to contaminants at workplace. Installation of industrial ventilation or local exhaust ventilation (LEV) system is the proposed method to reduce the risk. This paper discusses the past, present and future relating to LEV system in Malaysia. Current issues related to monitoring reported by Hygiene Technician in compliance with Occupational Safety and Health (Use of Standard Chemical Hazardous to Health Regulation 2000) carried out in several states in Malaysia as a sample. The nanotechnology is a new area at present and future. The involvement of government, employers and employees need to be justified due to the attention to prevent and control of any exposure. It is suggested that using the Computational Fluid Dynamic (CFD) simulation, a new design of LEV system can be upgraded and predicted.
    Matched MeSH terms: Nanotechnology
  2. Factors affecting molecular self-assembly and its mechanism
    Tan, Hueyling
    Scientific Research Journal, 2012;9(1):43-61.
    MyJurnal
    Molecular self-assembly is ubiquitous in nature and has emerged as a new approach to produce new materials in chemistry, engineering, nanotechnology, polymer science and materials. Molecular self-assembly has been attracting increasing interest from the scientific community in recent years due to its importance in understanding biology and a variety of diseases at the molecular level. In the last few years, considerable advances have been made in the use of peptides as building blocks to produce biological materials for wide range of applications, including fabricating novel supra-molecular structures and scaffolding for tissue repair. The study of biological self-assembly systems represents a significant advancement in molecular engineering and is a rapidly growing scientific and engineering field that crosses the boundaries of existing disciplines. Many self-assembling systems are range from bi- and tri-block copolymers to DNA structures as well as simple and complex proteins and peptides. The ultimate goal is to harness molecular self-assembly such that design and control of bottom-up processes is achieved thereby enabling exploitation of structures developed at the meso- and macro-scopic scale for the purposes of life and non-life science applications. Such aspirations can be achieved through understanding the fundamental principles behind the selforganisation and self-synthesis processes exhibited by biological systems.
    Matched MeSH terms: Nanotechnology
  3. A Dual Bioconjugated Virus-Like Nanoparticle as a Drug Delivery System and Comparison with a pH-Responsive Delivery System
    Biabanikhankahdani R, Ho KL, Alitheen NB, Tan WS
    Nanomaterials (Basel), 2018 Apr 13;8(4).
    PMID: 29652827 DOI: 10.3390/nano8040236
    Modifications of virus-like nanoparticles (VLNPs) using chemical conjugation techniques have brought the field of virology closer to nanotechnology. The huge surface area to volume ratio of VLNPs permits multiple copies of a targeting ligand and drugs to be attached per nanoparticle. By exploring the chemistry of truncated hepatitis B core antigen (tHBcAg) VLNPs, doxorubicin (DOX) was coupled covalently to the external surface of these nanoparticles via carboxylate groups. About 1600 DOX molecules were conjugated on each tHBcAg VLNP. Then, folic acid (FA) was conjugated to lysine residues of tHBcAg VLNPs to target the nanoparticles to cancer cells over-expressing folic acid receptor (FR). The result demonstrated that the dual bioconjugated tHBcAg VLNPs increased the accumulation and uptake of DOX in the human cervical and colorectal cancer cell lines compared with free DOX, resulting in enhanced cytotoxicity of DOX towards these cells. The fabrication of these dual bioconjugated nanoparticles is simple, and drugs can be easily conjugated with a high coupling efficacy to the VLNPs without any limitation with respect to the cargo's size or charge, as compared with the pH-responsive system based on tHBcAg VLNPs. These dual bioconjugated nanoparticles also have the potential to be modified for other combinatorial drug deliveries.
    Matched MeSH terms: Nanotechnology
  4. An insight into nanocellulose as soft condensed matter: Challenge and future prospective toward environmental sustainability
    Tan K, Heo S, Foo M, Chew IM, Yoo C
    Sci Total Environ, 2019 Feb 10;650(Pt 1):1309-1326.
    PMID: 30308818 DOI: 10.1016/j.scitotenv.2018.08.402
    Nanocellulose, a structural polysaccharide that has caught tremendous interests nowadays due to its renewability, inherent biocompatibility and biodegradability, abundance in resource, and environmental friendly nature. They are promising green nanomaterials derived from cellulosic biomass that can be disintegrated into cellulose nanofibrils (CNF) or cellulose nanocrystals (CNC), relying on their sensitivity to hydrolysis at the axial spacing of disordered domains. Owing to their unique mesoscopic characteristics at nanoscale, nanocellulose has been widely researched and incorporated as a reinforcement material in composite materials. The world has been consuming the natural resources at a much higher speed than the environment could regenerate. Today, as an uprising candidate in soft condensed matter physics, a growing interest was received owing to its unique self-assembly behaviour and quantum size effect in the formation of three-dimensional nanostructured material, could be utilised to address an increasing concern over global warming and environmental conservation. In spite of an emerging pool of knowledge on the nanocellulose downstream application, that was lacking of cross-disciplinary study of its role as a soft condensed matter for food, water and energy applications toward environmental sustainability. Here we aim to provide an insight for the latest development of cellulose nanotechnology arises from its fascinating physical and chemical characteristic for the interest of different technology holders.
    Matched MeSH terms: Nanotechnology
  5. Fulltext An Analytical Conductance Model for Gas Detection Based on a Zigzag Carbon Nanotube Sensor
    Hosseingholipourasl A, Hafizah Syed Ariffin S, Ahmadi MT, Rahimian Koloor SS, Petrů M, Hamzah A
    Sensors (Basel), 2020 Jan 08;20(2).
    PMID: 31936402 DOI: 10.3390/s20020357
    Recent advances in nanotechnology have revealed the superiority of nanocarbon species such as carbon nanotubes over other conventional materials for gas sensing applications. In this work, analytical modeling of the semiconducting zigzag carbon nanotube field-effect transistor (ZCNT-FET) based sensor for the detection of gas molecules is demonstrated. We propose new analytical models to strongly simulate and investigate the physical and electrical behavior of the ZCNT sensor in the presence of various gas molecules (CO2, H2O, and CH4). Therefore, we start with the modeling of the energy band structure by acquiring the new energy dispersion relation for the ZCNT and introducing the gas adsorption effects to the band structure model. Then, the electrical conductance of the ZCNT is modeled and formulated while the gas adsorption effect is considered in the conductance model. The band structure analysis indicates that, the semiconducting ZCNT experiences band gap variation after the adsorption of the gases. Furthermore, the bandgap variation influences the conductance of the ZCNT and the results exhibit increments of the ZCNT conductance in the presence of target gases while the minimum conductance shifted upward around the neutrality point. Besides, the I-V characteristics of the sensor are extracted from the conductance model and its variations after adsorption of different gas molecules are monitored and investigated. To verify the accuracy of the proposed models, the conductance model is compared with previous experimental and modeling data and a good consensus is observed. It can be concluded that the proposed analytical models can successfully be applied to predict sensor behavior against different gas molecules.
    Matched MeSH terms: Nanotechnology
  6. Advances of nanomaterials for air pollution remediation and their impacts on the environment
    Saleem H, Zaidi SJ, Ismail AF, Goh PS
    Chemosphere, 2022 Jan;287(Pt 2):132083.
    PMID: 34488054 DOI: 10.1016/j.chemosphere.2021.132083
    One of the most favorable environmental applications of nanotechnology has been in air pollution remediation in which different nanomaterials are used as nanoadsorbents, nanocatalysts, nanofilters, and nanosensors. The nanomaterials have the ability to adsorb several contaminants existing in the air. Also, certain semiconducting nanomaterials materials can be used for photocatalytic remediation. Air contamination control can also be achieved by nanostructured membranes with pores sufficiently small to separate various pollutants from the exhaust. Nanomaterial enabled sensors are also used for the detection of harmful gases such as hydrogen sulfide, sulphur dioxide, and nitrogen dioxide. Conversely, because of the uncertainties in addition to irregularities in size, shape as well as chemical compositions, the existence of some nanomaterials might cause harmful effects on the environment along with the health of people. Thus, concerns were expressed about the transport and conversion of nanoparticles discharged into the surroundings. This review critically examined and assessed the present literature on the application of nanomaterials in the air, together with its negative impacts. The main focus is placed on the application of carbon-based and metal-based nanomaterials for air pollution remediation. It is noted that these nanomaterials demonstrating fascinating properties for improving the environmental pollution remediation system.
    Matched MeSH terms: Nanotechnology
  7. Fulltext Biosynthesis of Silver Nanoparticles Using Brown Marine Macroalga, Sargassum Muticum Aqueous Extract
    Azizi S, Namvar F, Mahdavi M, Ahmad MB, Mohamad R
    Materials (Basel), 2013 Dec 18;6(12):5942-5950.
    PMID: 28788431 DOI: 10.3390/ma6125942
    Biological synthesis of nanoparticles is a relatively new emerging field of nanotechnology which has economic and eco-friendly benefits over chemical and physical processes of synthesis. In the present work, for the first time, the brown marine algae Sargassum muticum (S. muticum) aqueous extract was used as a reducing agent for the synthesis of nanostructure silver particles (Ag-NPs). Structural, morphological and optical properties of the synthesized nanoparticles have been characterized systematically by using FTIR, XRD, TEM and UV-Vis spectroscopy. The formation of Ag-NPs was confirmed through the presence of an intense absorption peak at 420 nm using a UV-visible spectrophotometer. A TEM image showed that the particles are spherical in shape with size ranging from 5 to 15 nm. The nanoparticles were crystalline in nature. This was confirmed by the XRD pattern. From the FTIR results, it can be seen that the reduction has mostly been carried out by sulphated polysaccharides present in S. muticum.
    Matched MeSH terms: Nanotechnology
  8. Nanotechnology based approaches for anti-diabetic drugs delivery
    Kesharwani P, Gorain B, Low SY, Tan SA, Ling ECS, Lim YK, et al.
    Diabetes Res Clin Pract, 2018 Feb;136:52-77.
    PMID: 29196152 DOI: 10.1016/j.diabres.2017.11.018
    Nanotechnology science has been diverged its application in several fields with the advantages to operate with nanometric range of objects. Emerging field of nanotechnology has been also being approached and applied in medical biology for improved efficacy and safety. Increased success in therapeutic field has focused several approaches in the treatment of the common metabolic disorder, diabetes. The development of nanocarriers for improved delivery of different oral hypoglycemic agents compared to conventional therapies includes nanoparticles (NPs), liposomes, dendrimer, niosomes and micelles, which produces great control over the increased blood glucose level and thus becoming an eye catching and most promising technology now-a-days. Besides, embellishment of nanocarriers with several ligands makes it more targeted delivery with the protection of entrapped hypoglycaemic agents against degradation, thereby optimizing prolonged blood glucose lowering effect. Thus, nanocarriers of hypoglycemic agents provide the aim towards improved diabetes management with minimized risk of acute and chronic complications. In this review, we provide an overview on distinctive features of each nano-based drug delivery system for diabetic treatment and current NPs applications in diabetes management.
    Matched MeSH terms: Nanotechnology
  9. Nanotechnology-based drug delivery systems for Alzheimer's disease management: Technical, industrial, and clinical challenges
    Wen MM, El-Salamouni NS, El-Refaie WM, Hazzah HA, Ali MM, Tosi G, et al.
    J Control Release, 2017 01 10;245:95-107.
    PMID: 27889394 DOI: 10.1016/j.jconrel.2016.11.025
    Alzheimer's disease (AD) is a neurodegenerative disease with high prevalence in the rapidly growing elderly population in the developing world. The currently FDA approved drugs for the management of symptomatology of AD are marketed mainly as conventional oral medications. Due to their gastrointestinal side effects and lack of brain targeting, these drugs and dosage regiments hinder patient compliance and lead to treatment discontinuation. Nanotechnology-based drug delivery systems (NTDDS) administered by different routes can be considered as promising tools to improve patient compliance and achieve better therapeutic outcomes. Despite extensive research, literature screening revealed that clinical activities involving NTDDS application in research for AD are lagging compared to NTDDS for other diseases such as cancers. The industrial perspectives, processability, and cost/benefit ratio of using NTDDS for AD treatment are usually overlooked. Moreover, active and passive immunization against AD are by far the mostly studied alternative AD therapies because conventional oral drug therapy is not yielding satisfactorily results. NTDDS of approved drugs appear promising to transform this research from 'paper to clinic' and raise hope for AD sufferers and their caretakers. This review summarizes the recent studies conducted on NTDDS for AD treatment, with a primary focus on the industrial perspectives and processability. Additionally, it highlights the ongoing clinical trials for AD management.
    Matched MeSH terms: Nanotechnology
  10. Fulltext Innovative Therapeutic Approaches Based on Nanotechnology for the Treatment and Management of Tuberculosis
    Kia P, Ruman U, Pratiwi AR, Hussein MZ
    Int J Nanomedicine, 2023;18:1159-1191.
    PMID: 36919095 DOI: 10.2147/IJN.S364634
    Tuberculosis (TB), derived from bacterium named Mycobacterium tuberculosis, has become one of the worst infectious and contagious illnesses in the world after HIV/AIDS. Long-term therapy, a high pill burden, lack of compliance, and strict management regimens are disadvantages which resulted in the extensively drug-resistant (XDR) along with multidrug-resistant (MDR) in the treatment of TB. One of the main thrust areas for the current scenario is the development of innovative intervention tools for early diagnosis and therapeutics towards Mycobacterium tuberculosis (MTB). This review discusses various nanotherapeutic agents that have been developed for MTB diagnostics, anti-TB drugs and vaccine. Undoubtedly, the concept of employing nanoparticles (NPs) has strong potential in this therapy and offers impressive outcomes to conquer the disease. Nanocarriers with different types were designed for drug delivery applications via various administration methods. Controlling and maintaining the drug release might be an example of the benefits of utilizing a drug-loaded NP in TB therapy over conventional drug therapy. Furthermore, the drug-encapsulated NP is able to lessen dosage regimen and can resolve the problems of insufficient compliance. Over the past decade, NPs were developed in both diagnostic and therapeutic methods, while on the other hand, the therapeutic system has increased. These "theranostic" NPs were designed for nuclear imaging, optical imaging, ultrasound, imaging with magnetic resonance and the computed tomography, which includes both single-photon computed tomography and positron emission tomography. More specifically, the current manuscript focuses on the status of therapeutic and diagnostic approaches in the treatment of TB.
    Matched MeSH terms: Nanotechnology
  11. Fulltext Critical Review on Nutritional, Bioactive, and Medicinal Potential of Spices and Herbs and Their Application in Food Fortification and Nanotechnology
    Mandal D, Sarkar T, Chakraborty R
    Appl Biochem Biotechnol, 2023 Feb;195(2):1319-1513.
    PMID: 36219334 DOI: 10.1007/s12010-022-04132-y
    Medicinal or herbal spices are grown in tropical moist evergreen forestland, surrounding most of the tropical and subtropical regions of Eastern Himalayas in India (Sikkim, Darjeeling regions), Bhutan, Nepal, Pakistan, Iran, Afghanistan, a few Central Asian countries, Middle East, USA, Europe, South East Asia, Japan, Malaysia, and Indonesia. According to the cultivation region surrounded, economic value, and vogue, these spices can be classified into major, minor, and colored tropical spices. In total, 24 tropical spices and herbs (cardamom, black jeera, fennel, poppy, coriander, fenugreek, bay leaves, clove, chili, cassia bark, black pepper, nutmeg, black mustard, turmeric, saffron, star anise, onion, dill, asafoetida, celery, allspice, kokum, greater galangal, and sweet flag) are described in this review. These spices show many pharmacological activities like anti-inflammatory, antimicrobial, anti-diabetic, anti-obesity, cardiovascular, gastrointestinal, central nervous system, and antioxidant activities. Numerous bioactive compounds are present in these selected spices, such as 1,8-cineole, monoterpene hydrocarbons, γ-terpinene, cuminaldehyde, trans-anethole, fenchone, estragole, benzylisoquinoline alkaloids, eugenol, cinnamaldehyde, piperine, linalool, malabaricone C, safrole, myristicin, elemicin, sinigrin, curcumin, bidemethoxycurcumin, dimethoxycurcumin, crocin, picrocrocin, quercetin, quercetin 4'-O-β-glucoside, apiol, carvone, limonene, α-phellandrene, galactomannan, rosmarinic acid, limonene, capsaicinoids, eugenol, garcinol, and α-asarone. Other than that, various spices are used to synthesize different types of metal-based and polymer-based nanoparticles like zinc oxide, gold, silver, selenium, silica, and chitosan nanoparticles which provide beneficial health effects such as antioxidant, anti-carcinogenic, anti-diabetic, enzyme retardation effect, and antimicrobial activity. The nanoparticles can also be used in environmental pollution management like dye decolorization and in chemical industries to enhance the rate of reaction by the use of catalytic activity of the nanoparticles. The nutritional value, phytochemical properties, health advantages, and both traditional and modern applications of these spices, along with their functions in food fortification, have been thoroughly discussed in this review.
    Matched MeSH terms: Nanotechnology
  12. Fulltext Optical nano antennas: state of the art, scope and challenges as a biosensor along with human exposure to nano-toxicology
    Kausar AS, Reza AW, Latef TA, Ullah MH, Karim ME
    Sensors (Basel), 2015 Apr 15;15(4):8787-831.
    PMID: 25884787 DOI: 10.3390/s150408787
    The concept of optical antennas in physical optics is still evolving. Like the antennas used in the radio frequency (RF) regime, the aspiration of optical antennas is to localize the free propagating radiation energy, and vice versa. For this purpose, optical antennas utilize the distinctive properties of metal nanostructures, which are strong plasmonic coupling elements at the optical regime. The concept of optical antennas is being advanced technologically and they are projected to be substitute devices for detection in the millimeter, infrared, and visible regimes. At present, their potential benefits in light detection, which include polarization dependency, tunability, and quick response times have been successfully demonstrated. Optical antennas also can be seen as directionally responsive elements for point detectors. This review provides an overview of the historical background of the topic, along with the basic concepts and parameters of optical antennas. One of the major parts of this review covers the use of optical antennas in biosensing, presenting biosensing applications with a broad description using different types of data. We have also mentioned the basic challenges in the path of the universal use of optical biosensors, where we have also discussed some legal matters.
    Matched MeSH terms: Nanotechnology
  13. Fulltext Exceedingly biocompatible and thin-layered reduced graphene oxide nanosheets using an eco-friendly mushroom extract strategy
    Muthoosamy K, Bai RG, Abubakar IB, Sudheer SM, Lim HN, Loh HS, et al.
    Int J Nanomedicine, 2015;10:1505-19.
    PMID: 25759577 DOI: 10.2147/IJN.S75213
    PURPOSE: A simple, one-pot strategy was used to synthesize reduced graphene oxide (RGO) nanosheets by utilizing an easily available over-the-counter medicinal and edible mushroom, Ganoderma lucidum.

    METHODS: The mushroom was boiled in hot water to liberate the polysaccharides, the extract of which was then used directly for the reduction of graphene oxide. The abundance of polysaccharides present in the mushroom serves as a good reducing agent. The proposed strategy evades the use of harmful and expensive chemicals and avoids the typical tedious reaction methods.

    RESULTS: More importantly, the mushroom extract can be easily separated from the product without generating any residual byproducts and can be reused at least three times with good conversion efficiency (75%). It was readily dispersible in water without the need of ultrasonication or any surfactants; whereas 5 minutes of ultrasonication with various solvents produced RGO which was stable for the tested period of 1 year. Based on electrochemical measurements, the followed method did not jeopardize RGO's electrical conductivity. Moreover, the obtained RGO was highly biocompatible to not only colon (HT-29) and brain (U87MG) cancer cells, but was also viable towards normal cells (MRC-5).

    CONCLUSION: Besides being eco-friendly, this mushroom based approach is easily scalable and demonstrates remarkable RGO stability and biocompatibility, even without any form of functionalization.

    Matched MeSH terms: Nanotechnology
  14. Fulltext Nanotechnology and its use in imaging and drug delivery (Review)
    Sim S, Wong NK
    Biomed Rep, 2021 May;14(5):42.
    PMID: 33728048 DOI: 10.3892/br.2021.1418
    Nanotechnology is the exploitation of the unique properties of materials at the nanoscale. Nanotechnology has gained popularity in several industries, as it offers better built and smarter products. The application of nanotechnology in medicine and healthcare is referred to as nanomedicine, and it has been used to combat some of the most common diseases, including cardiovascular diseases and cancer. The present review provides an overview of the recent advances of nanotechnology in the aspects of imaging and drug delivery.
    Matched MeSH terms: Nanotechnology
  15. Fulltext Formation and yield of multi-walled carbon nanotubes synthesized via chemical vapour deposition routes using different metal-based catalysts of FeCoNiAl, CoNiAl and FeNiAl-LDH
    Hussein MZ, Jaafar AM, Yahaya AH, Masarudin MJ, Zainal Z
    Int J Mol Sci, 2014;15(11):20254-65.
    PMID: 25380526 DOI: 10.3390/ijms151120254
    Multi-walled carbon nanotubes (MWCNTs) were prepared via chemical vapor deposition (CVD) using a series of different catalysts, derived from FeCoNiAl, CoNiAl and FeNiAl layered double hydroxides (LDHs). Catalyst-active particles were obtained by calcination of LDHs at 800 °C for 5 h. Nitrogen and hexane were used as the carrier gas and carbon source respectively, for preparation of MWCNTs using CVD methods at 800 °C. MWCNTs were allowed to grow for 30 min on the catalyst spread on an alumina boat in a quartz tube. The materials were subsequently characterized through X-ray diffraction, Fourier transform infrared spectroscopy, surface area analysis, field emission scanning electron microscopy and transmission electron microscopy. It was determined that size and yield of MWCNTs varied depending on the type of LDH catalyst precursor that is used during synthesis. MWCNTs obtained using CoNiAl-LDH as the catalyst precursor showed smaller diameter and higher yield compared to FeCoNiAl and FeNiAl LDHs.
    Matched MeSH terms: Nanotechnology/methods*
  16. Fulltext Modeling and analysis of a microresonating biosensor for detection of Salmonella bacteria in human blood
    Bahadoran M, Noorden AF, Chaudhary K, Mohajer FS, Aziz MS, Hashim S, et al.
    Sensors (Basel), 2014;14(7):12885-99.
    PMID: 25046015 DOI: 10.3390/s140712885
    A new photonics biosensor configuration comprising a Double-side Ring Add-drop Filter microring resonator (DR-ADF) made from SiO2-TiO2 material is proposed for the detection of Salmonella bacteria (SB) in blood. The scattering matrix method using inductive calculation is used to determine the output signal's intensities in the blood with and without presence of Salmonella. The change in refractive index due to the reaction of Salmonella bacteria with its applied antibody on the flagellin layer loaded on the sensing and detecting microresonator causes the increase in through and dropper port's intensities of the output signal which leads to the detection of SB in blood. A shift in the output signal wavelength is observed with resolution of 0.01 nm. The change in intensity and shift in wavelength is analyzed with respect to the change in the refractive index which contributes toward achieving an ultra-high sensitivity of 95,500 nm/RIU which is almost two orders higher than that of reported from single ring sensors and the limit of detection is in the order of 1 × 10(-8) RIU. In applications, such a system can be employed for a high sensitive and fast detection of bacteria.
    Matched MeSH terms: Nanotechnology/methods
  17. Vaginal drug delivery: strategies and concerns in polymeric nanoparticle development
    Wong TW, Dhanawat M, Rathbone MJ
    Expert Opin Drug Deliv, 2014 Sep;11(9):1419-34.
    PMID: 24960192 DOI: 10.1517/17425247.2014.924499
    Vaginal infection is widespread and > 80% of females encounter such infections during their lives. Topical treatment and prevention of vaginal infection allows direct therapeutic action, reduced drug doses and adverse effects, convenient administration and improved compliance. The advent of nanotechnology results in the use of nanoparticulate vehicle to control drug release, to enhance dosage form mucoadhesive properties and vaginal retention, and to promote mucus and epithelium permeation for both extracellular and intracellular drug delivery.
    Matched MeSH terms: Nanotechnology/methods
  18. Fulltext Fast synthesis of multilayer carbon nanotubes from camphor oil as an energy storage material
    TermehYousefi A, Bagheri S, Shinji K, Rouhi J, Rusop Mahmood M, Ikeda S
    Biomed Res Int, 2014;2014:691537.
    PMID: 25258714 DOI: 10.1155/2014/691537
    Among the wide range of renewable energy sources, the ever-increasing demand for electricity storage represents an emerging challenge. Utilizing carbon nanotubes (CNTs) for energy storage is closely being scrutinized due to the promising performance on top of their extraordinary features. In this work, well-aligned multilayer carbon nanotubes were successfully synthesized on a porous silicon (PSi) substrate in a fast process using renewable natural essential oil via chemical vapor deposition (CVD). Considering the influx of vaporized multilayer vertical carbon nanotubes (MVCNTs) to the PSi, the diameter distribution increased as the flow rate decreased in the reactor. Raman spectroscopy results indicated that the crystalline quality of the carbon nanotubes structure exhibits no major variation despite changes in the flow rate. Fourier transform infrared (FT-IR) spectra confirmed the hexagonal structure of the carbon nanotubes because of the presence of a peak corresponding to the carbon double bond. Field emission scanning electron microscopy (FESEM) images showed multilayer nanotubes, each with different diameters with long and straight multiwall tubes. Moreover, the temperature programmed desorption (TPD) method has been used to analyze the hydrogen storage properties of MVCNTs, which indicates that hydrogen adsorption sites exist on the synthesized multilayer CNTs.
    Matched MeSH terms: Nanotechnology/methods*
  19. Fulltext An investigation on the thermal effusivity of nanofluids Containing Al(2)O(3) and CuO nanoparticles
    Noroozi M, Zakaria A, Moksin MM, Wahab ZA
    Int J Mol Sci, 2012;13(8):10350-8.
    PMID: 22949865 DOI: 10.3390/ijms130810350
    The thermal effusivity of Al(2)O(3) and CuO nanofluids in different base fluids, i.e., deionized water, ethylene glycol and olive oil were investigated. The nanofluids, nanoparticles dispersed in base fluids; were prepared by mixing Al(2)O(3), CuO nanopowder and the base fluids using sonication with high-powered pulses to ensure a good uniform dispersion of nanoparticles in the base fluids. The morphology of the particles in the base fluids was investigated by transmission electron microscopy (TEM). In this study, a phase frequency scan of the front pyroelectric configuration technique, with a thermally thick PVDF pyroelectric sensor and sample, was used to measure the thermal effusivity of the prepared nanofluids. The experimental results of the thermal effusivity of the studied solvents (deionized water, ethylene glycol and olive oil) showed good agreement with literature values, and were reduced in the presence of nanoparticles. The thermal effusivity of the nanofluid was found to be particularly sensitive to its base fluid and the type of nanoparticles.
    Matched MeSH terms: Nanotechnology/methods*
  20. Fulltext Facile hydrothermal preparation of titanium dioxide decorated reduced graphene oxide nanocomposite
    Chang BY, Huang NM, An'amt MN, Marlinda AR, Norazriena Y, Muhamad MR, et al.
    Int J Nanomedicine, 2012;7:3379-87.
    PMID: 22848166 DOI: 10.2147/IJN.S28189
    A simple single-stage approach, based on the hydrothermal technique, has been introduced to synthesize reduced graphene oxide/titanium dioxide nanocomposites. The titanium dioxide nanoparticles are formed at the same time as the graphene oxide is reduced to graphene. The triethanolamine used in the process has two roles. It acts as a reducing agent for the graphene oxide as well as a capping agent, allowing the formation of titanium dioxide nanoparticles with a narrow size distribution (~20 nm). Transmission electron micrographs show that the nanoparticles are uniformly distributed on the reduced graphene oxide nanosheet. Thermogravimetric analysis shows the nanocomposites have an enhanced thermal stability over the original components. The potential applications for this technology were demonstrated by the use of a reduced graphene oxide/titanium dioxide nanocomposite-modified glassy carbon electrode, which enhanced the electrochemical performance compared to a conventional glassy carbon electrode when interacting with mercury(II) ions in potassium chloride electrolyte.
    Matched MeSH terms: Nanotechnology/methods*
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