Abstract: Removal of various toxic species from aqueous streams is of great importance. Sorption is one of the important remediation procedures as it involves the use of cheap and easily available materials. Also the advantage of regeneration of the sorbent involves the possibility of using novel sorbents. Nanosorbents are very important as the removal is based on the surface phenomena and this is greatly affected by surface charge and area. Functionalization has been very important to bring about the removal of metal ions with greater selectivity.
Abstract: The preparation of Cu nanoparticles (NPs) through the reduction of copper ions by sodium borohydride in the presence of sodium polyacrylate with a molecular weight of 1200 is reported. Cu NPs were synthesized at a concentration of copper salt equal to 2.5, 5, and 10 mM, and at a molar ratio of copper ions and monomeric unit of polyacrylate equal to 1:2. The as-prepared Cu NPs have diameters of about 2.5–3 nm for copper concentrations of 2.5 and 5 mM, and 6 nm for copper concentration of 10 mM. Depending on the copper salt concentration and concentration of additionally added polyacrylate to Cu particle dispersion, primarily formed NPs grow through the process of aggregation and/or coalescence into clusters and/or particles with a diameter between 20–100 nm. The amount of additionally added sodium polyacrylate influences the stability of Cu particles against air oxidation. The catalytic efficiency of the prepared Cu particles for the reduction of 4-nitrophenol is discussed.
Abstract: Bioreduction of silver nanoparticles (AgNPs) from silver ions (Ag+) using water extract of Thai basil leaf was successfully carried out. The basil leaf extract provided a reducing agent and stabilizing agent for a synthesis of metal nanoparticles. Silver nanoparticles received from cut and uncut basil leaf was compared. The resulting silver nanoparticles are characterized by UV-Vis spectroscopy. The maximum intensities of silver nanoparticle from cut and uncut basil leaf were 410 and 420, respectively. The techniques involved are simple, eco-friendly and rapid.
Abstract: In this work we describe the preparation of NanoSilver/methylcellulose hydrogel containing silver nanoparticles (NPs) for topical bactericidal applications. Highly concentrated dispersion of silver NPs as high as of 5g/L of silver with diameter of 10nm was prepared by reduction of AgNO3 via strong reducing agent NaBH4. Silver NPs were stabilized by addition of sodium polyacrylate in order to prevent their aggregation at such high concentration. This way synthesized silver NPs were subsequently incorporated into methylcellulose suspension at elevated temperature resulting in formation of NanoSilver/methylcellulose hydrogel when temperature cooled down to laboratory conditions. In vitro antibacterial activity assay proved high bactericidal and fungicidal efficiency of silver NPs alone in the form of dispersion as well as in the form of hydrogel against broad spectrum of bacteria and yeasts including highly multiresistant strains such as methicillin-resistant Staphylococcus aureus. A very low concentrations of silver as low as 0.84mg/L Ag in as-prepared dispersion gave antibacterial performance. NanoSilver/methylcellulose hydrogel showed antibacterial action at the lowest used silver concentration equal to 25mg/L. Such prepared NanoSilver/methylcellulose hydrogel represent promising topical antimicrobial formulation for treatment of burns and wounds.
Abstract: Gold nanoparticles (AuNPs) have gained increasing
interest in recent times. This is greatly due to their special features,
which include unusual optical and electronic properties, high stability
and biological compatibility, controllable morphology and size
dispersion, and easy surface functionalization. In typical synthesis,
AuNPs were produced by reduction of gold salt AuCl4 in an
appropriate solvent. A stabilizing agent was added to prevent the
particles from aggregating. The antibacterial activity of different
sizes of gold nanoparticles was investigated against Staphylococcus
aureus, Salmonella typhi and Pseudomonas pneumonia using the disk
diffusion method in a Müeller–Hinton Agar. The Au-NPs were
effective against all bacteria tested. That the Au-NPs were
successfully synthesized in suspension and were used to study the
antibacterial activity of the two medicinal plants against some
bacterial pathogens suggests that Au-NPs can be employed as an
effective bacteria inhibitor and may be an effective tool in medical
field. The study clearly showed that the Au-NPs exhibiting inhibition
towards the tested pathogenic bacteria in vitro could have the same
effects in vivo and thus may be useful in the medical field if well
researched into.
Abstract: In this experiment Polystyrene/Zinc-oxide (PS/ZnO) nanocomposite fibers were produced by electrospinning technique using limonene as a green solvent. First, the morphology of electrospun pure polystyrene (PS) and PS/ZnO nanocomposite fibers investigated by SEM. Results showed the PS fiber diameter decreased by increasing concentration of Zinc Oxide nanoparticles (ZnO NPs). Thermo Gravimetric Analysis (TGA) results showed thermal stability of nanocomposites increased by increasing ZnO NPs in PS electrospun fibers. Considering Differential Scanning Calorimeter (DSC) thermograms for electrospun PS fibers indicated that introduction of ZnO NPs into fibers affects the glass transition temperature (Tg) by reducing it. Also, UV protection properties of nanocomposite fibers were increased by increasing ZnO concentration. Evaluating the effect of metal oxide NPs amount on mechanical properties of electrospun layer showed that tensile strength and elasticity modulus of the electrospun layer of PS increased by addition of ZnO NPs. X-ray diffraction (XRD) pattern of nanopcomposite fibers confirmed the presence of NPs in the samples.
Abstract: Pyrazinamide (PZA) is among the first-line pro-drugs in the tuberculosis (TB) combination chemotherapy used to treat Mycobacterium tuberculosis. Numerous reports have suggested that hepatotoxicity due to pyrazinamide in patients is due to inappropriate dosing. It is, therefore necessary to develop sensitive and reliable techniques for determining the PZA metabolic profile of diagnosed patients promptly and at point-of-care. This study reports the determination of PZA based on nanobiosensor systems developed from disuccinimidyl octanedioate modified Cytochrome P450-2E1 (CYP2E1) electrodeposited on gold substrates derivatised with (poly(8-anilino-1-napthalene sulphonic acid) PANSA/PVP-AgNPs nanocomposites. The rapid and sensitive amperometric PZA detection gave a dynamic linear range of 2µM to 16µM revealing a
limit of detection of 0.044µM and a sensitivity of 1.38µA/µM. The Michaelis-Menten parameters; KM, KM app and IMAX were calculated to be 6.0µM, 1.41µM and 1.51x10-6 A, respectively, indicating a nanobiosensor suitable for use in serum.
Abstract: This paper discusses E-government, in particular the challenges that face its development and widespread adoption in Saudi Arabia. E-government can be defined based on an existing set of requirements. E-government has been implemented for a considerable time in developed countries. However, E-government services still face many challenges in their implementation and general adoption in Saudi Arabia. In addition, the literature review and the discussion identify the influential factors, such as quality of service, diffusion of innovation, computer and information literacy, culture, lack of awareness, technical infrastructure, website design, and security, that affect the citizens’ intention to adopt E-government services in Saudi Arabia. Consequently, these factors have been integrated in a new model that would influence citizen to adopt E- government services. Therefore, this research presents an integrated model for ascertaining the intention to adopt E-government services and thereby aiding governments in accessing what is required to increase adoption.
Abstract: Among the many promising nanomaterials with antifungal properties, metal nanoparticles (silver nanoparticles) stand out due to their high chemical activity. Therefore, the aim of this study was to evaluate the effect of silver nanoparticles (AgNPs) against Phomopsis sp. AgNPs were synthesized by silver nitrate reduction with sodium citrate and stabilized with ammonia. The synthesized AgNPs have further been characterized by UV/Visible spectroscopy, Biophysical techniques like Dynamic light scattering (DLS) and Scanning Electron Microscopy (SEM). The average diameter of the prepared silver colloidal nanoparticles was about 52 nm. Absolute inhibitions (100%) were observed on treated with a 270 and 540 µg ml-1 concentration of AgNPs. The results from the study of the AgNPs antifungal effect are significant and suggest that the synthesized silver nanoparticles may have an advantage compared with conventional fungicides.
Abstract: Silver/polylactide nanocomposites (Ag/PLA-NCs) were
synthesized via chemical reduction method in diphase solvent. Silver
nitrate and sodium borohydride were used as a silver precursor
and reducing agent in the polylactide (PLA). The properties of
Ag/PLA-NCs were studied as a function of the weight percentages
of silver nanoparticles (8, 16 and 32 wt% of Ag-NPs) relative to
the weight of PLA. The Ag/PLA-NCs were characterized by Xray
diffraction (XRD), transmission electron microscopy (TEM),
electro-optical microscopy (EOM), UV-visible spectroscopy (UV-vis)
and Fourier transform infrared spectroscopy (FT-IR). XRD patterns
confirmed that Ag-NPs crystallographic planes were face centered
cubic (fcc) type. TEM images showed that mean diameters of Ag-NPs
were 3.30, 3.80 and 4.80 nm. Electro-optical microscopy revealed
excellent dispersion and interaction between Ag-NPs and PLA films.
The generation of silver nanoparticles was confirmed from the UVvisible
spectra. FT-IR spectra showed that there were no significant
differences between PLA and Ag/PLA-NCs films. The synthesized
Ag/PLA-NCs were stable in organic solution over a long period of
time without sign of precipitation.
Abstract: Semiconductor nanomaterials like TiO2 nanoparticles
(TiO2-NPs) approximately less than 100 nm in diameter have become
a new generation of advanced materials due to their novel and
interesting optical, dielectric, and photo-catalytic properties. With the
increasing use of NPs in commerce, to date few studies have
investigated the toxicological and environmental effects of NPs.
Motivated by the importance of TiO2-NPs that may contribute to the
cancer research field especially from the treatment prospective
together with the fractal analysis technique, we have investigated the
effect of TiO2-NPs on colony morphology in the dark condition
using fractal dimension as a key morphological characterization
parameter. The aim of this work is mainly to investigate the cytotoxic
effects of TiO2-NPs in the dark on the growth of human cervical
carcinoma (HeLa) cell colonies from morphological aspect. The in
vitro studies were carried out together with the image processing
technique and fractal analysis. It was found that, these colonies were
abnormal in shape and size. Moreover, the size of the control
colonies appeared to be larger than those of the treated group. The
mean Df +/- SEM of the colonies in untreated cultures was
1.085±0.019, N= 25, while that of the cultures treated with TiO2-NPs
was 1.287±0.045. It was found that the circularity of the control
group (0.401±0.071) is higher than that of the treated group
(0.103±0.042). The same tendency was found in the diameter
parameters which are 1161.30±219.56 μm and 852.28±206.50 μm
for the control and treated group respectively. Possible explanation of
the results was discussed, though more works need to be done in
terms of the for mechanism aspects. Finally, our results indicate that
fractal dimension can serve as a useful feature, by itself or in
conjunction with other shape features, in the classification of cancer
colonies.
Abstract: Single nucleotide polymorphisms (SNPs) hold much promise as a basis for disease-gene association. However, research is limited by the cost of genotyping the tremendous number of SNPs. Therefore, it is important to identify a small subset of informative SNPs, the so-called tag SNPs. This subset consists of selected SNPs of the genotypes, and accurately represents the rest of the SNPs. Furthermore, an effective evaluation method is needed to evaluate prediction accuracy of a set of tag SNPs. In this paper, a genetic algorithm (GA) is applied to tag SNP problems, and the K-nearest neighbor (K-NN) serves as a prediction method of tag SNP selection. The experimental data used was taken from the HapMap project; it consists of genotype data rather than haplotype data. The proposed method consistently identified tag SNPs with considerably better prediction accuracy than methods from the literature. At the same time, the number of tag SNPs identified was smaller than the number of tag SNPs in the other methods. The run time of the proposed method was much shorter than the run time of the SVM/STSA method when the same accuracy was reached.
Abstract: In this study, to accurately predict cavitation of a
centrifugal pump, numerical analysis was compared with experimental
results modeled on a small industrial centrifugal pump. In this study,
numerical analysis was compared with experimental results modeled
on a small industrial centrifugal pump for reliable prediction on
cavitation of a centrifugal pump. To improve validity of the numerical
analysis, transient analysis was conducted on the calculated domain of
full-type geometry, such as an experimental apparatus. The numerical
analysis from the results was considered to be a reliable prediction of
cavitaion.
Abstract: 16-Mercaptohexadecanoic acid (MHDA) and tripeptide glutathione conjugated with gold nanoparticles (Au-NPs) are characterized by Fourier Transform InfaRared (FTIR) spectroscopy combined with Surface-enhanced Raman scattering (SERS) spectroscopy. Surface Plasmon Resonance (SPR) technique based on FTIR spectroscopy has become an important tool in biophysics, which is perspective for the study of organic compounds. FTIR-spectra of MHDA shows the line at 2500 cm-1 attributed to thiol group which is modified by presence of Au-NPs, suggesting the formation of bond between thiol group and gold. We also can observe the peaks originate from characteristic chemical group. A Raman spectrum of the same sample is also promising. Our preliminary experiments confirm that SERS-effect takes place for MHDA connected with Au-NPs and enable us to detected small number (less than 106 cm-2) of MHDA molecules. Combination of spectroscopy methods: FTIR and SERS – enable to study optical properties of Au- NPs and immobilized bio-molecules in context of a bio-nano-sensors.
Abstract: Identifying the nature of protein-nanoparticle
interactions and favored binding sites is an important issue in
functional characterization of biomolecules and their physiological
responses. Herein, interaction of silver nanoparticles with lysozyme
as a model protein has been monitored via fluorescence spectroscopy.
Formation of complex between the biomolecule and silver
nanoparticles (AgNPs) induced a steady state reduction in the
fluorescence intensity of protein at different concentrations of
nanoparticles. Tryptophan fluorescence quenching spectra suggested
that silver nanoparticles act as a foreign quencher, approaching the
protein via this residue. Analysis of the Stern-Volmer plot showed
quenching constant of 3.73 μM−1. Moreover, a single binding site in
lysozyme is suggested to play role during interaction with AgNPs,
having low affinity of binding compared to gold nanoparticles.
Unfolding studies of lysozyme showed that complex of lysozyme-
AgNPs has not undergone structural perturbations compared to the
bare protein. Results of this effort will pave the way for utilization of
sensitive spectroscopic techniques for rational design of
nanobiomaterials in biomedical applications.
Abstract: The expression of LFA-1 diverges from the
physiological condition, thus active targeting carrier can provide the
benefits from difference into LFA-1 expression in various conditions.
Here, the selectivity of cIBR-conjugated nanoparticles (cIBR-NPs),
in terms of uptake, was investigated using PBMCs, Mixed PBMCMolt-
3 cells and Molt-3 cells. The expressions of LFA-1 on Molt-3
cells, from flow cytometry and Western blot, possessed the highest
level whereas PBMCs showed the lowest level. The kinetic uptake
profiles of cIBR-NPs were obtained by flow cytometry, which the
degree of cellular uptake presented a similar trend with the level of
LFA-1 indicating the influence of LFA-1 expression on the cellular
uptake of cIBR-NPs. The conformation of LFA-1 had a slight effect
on the cellular uptake of cIBR-NPs. Overall we demonstrated that
cIBR-NPs enhanced cellular uptake and improved the selectivity of
drug carriers to LFA-1 on the leukemia cells, which related with the
order of LFA-1 expression.
Abstract: Spherical shaped magnetite (Fe3O4) and Au@Fe3O4
nanoparticles were successfully synthesized from Fe electrodes
immersed in water with CTAB surfactant and HAuCl4 solution using
simple method-pulsed plasma in liquid, without the use of dopants or
special conditions for stabilization. Vibrating sample magnetometer
indicated ferromagnetic behavior of particles at room temperature with
coercivity and saturation magnetization of (Hc=105 Oe, Ms=6.83
emu/g) for Fe3O4 and (Hc=175, Ms=3.56emu/g) for Au@Fe3O4
nanoparticles. Structure and morphology of nanoparticles were
characterized by X-ray Diffraction analysis and HR-TEM
measurements. The cytotoxicity of nanoparticles was indicated using a
XTT assay to be very low (cell viability: 98-89% with Fe3O4 and
99-91% for Au@Fe3O4 NPs).
Abstract: We report a lithography-free approach to fabricate the
biomimetics, quasi-beehive Si nanostructures (QBSNs), on
Si-substrates. The self-assembled SiGe nanoislands via the strain
induced surface roughening (Asaro-Tiller-Grinfeld instability) during
in-situ annealing play a key role as patterned sacrifice regions for
subsequent reactive ion etching (RIE) process performed for
fabricating quasi-beehive nanostructures on Si-substrates. As the
measurements of field emission, the bare QBSNs show poor field
emission performance, resulted from the existence of the native oxide
layer which forms an insurmountable barrier for electron emission. In
order to dramatically improve the field emission characteristics, the
platinum nanopillars (Pt-NPs) were deposited on QBSNs to form
Pt-NPs/QBSNs heterostructures. The turn-on field of Pt-NPs/QBSNs
is as low as 2.29 V/μm (corresponding current density of 1 μA/cm2),
and the field enhancement factor (β-value) is significantly increased to
6067. More importantly, the uniform and continuous electrons excite
light emission, due to the surrounding filed emitters from
Pt-NPs/QBSNs, can be easily obtained. This approach does not require
an expensive photolithographic process and possesses great potential
for applications.
Abstract: Magnetic Nanoparticles (MNPs) have great potential
to overcome many of the shortcomings of the present diagnostic and
therapeutic approaches used in cancer diagnosis and treatment. This
Literature review discusses the use of Magnetic Nanoparticles
focusing mainly on Iron oxide based MNPs in cancer imaging using
MRI.
Abstract: In this study we investigate silica nanoparticle (SiO2- NP) effects on the structure and phase properties of supported lipid monolayers and bilayers, coupling surface pressure measurements, fluorescence microscopy and atomic force microscopy. SiO2-NPs typically in size range of 10nm to 100 nm in diameter are tested. Our results suggest first that lipid molecules organization depends to their nature. Secondly, lipid molecules in the vinicity of big aggregates nanoparticles organize in liquid condensed phase whereas small aggregates are localized in both fluid liquid-expanded (LE) and liquid-condenced (LC). We demonstrated also by atomic force microscopy that by measuring friction forces it is possible to get information as if nanoparticle aggregates are recovered or not by lipid monolayers and bilayers.