Comparative Characterization Study Research Articles

Preparation of novel cisplatin-conjugated hollow gold nanospheres for targeting cervical cancer.

Cervical cancer is a deadly gynecological malignancy in need of innovative treatment strategies. Emerging preclinical data has suggested the benefits of nanocarriers over the traditional chemotherapy for cancer treatment. In particular, gold nanoparticles are gaining popularity due to gold's inert nature, limited side effects, good cytocompatibility, and flexibility in preparation/modification. We conjugated polyethylene glycol (PEG) with hollow gold nanospheres (HGNs) and loaded the pegylated HGNs with an anticancer drug, cisplatin to target cervical cancer. HGNs were irradiated with noninfrared laser to increase the penetration of drug into tumor tissue and improve the delivery of cisplatin. We investigated the comparative characterization studies of prepared cisplatin loaded pegylated HGNs (cis PEG-HGNs), free cisplatin, cisplatin loaded HGNs (cis-HGNs), cis PEG-HGNs without laser, and cis PEG-HGNs with laser and its effects over cervical cancer cells. Transmission electron microscopy photomicrographs confirmed the integrity of prepared HGNs. While no significant difference was observed between encapsulation efficiency and drug loading of cis-HGNs (84.6%) and cis PEG-HGNs (86.7%), the encapsulation efficiency increased almost twice in HGNs, compared with control gold nanoparticles (GNs) because of the hollow cavity in HGNs. In-vitro cytotoxicity was measured by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay using HeLa cells. With irradiation, HGNs induced much elevated cytotoxicity. Not only HGNs were internalized by HeLa cells, they were retained in the cellular compartment. We also tested formulations in vivo and observed that the irradiated cis-HGNs and cis PEG-HGNs were most effective in regressing tumors in mice.

Comparative Study of the Physicochemical Characterization and Quality of Edible Vegetable Oils

The comparative study of physicochemical characterization and quality of edible vegetable oils was done in this work using standard analytical techniques. These oils include: Elaeis guineensis jacquin (palm oil), Glycine max (L.)Merr. (soybean oil),Cocus nucifera (coconut oil), Arachis hypogaea L.(groundnut oil), Olea europaea (Olive oil), Sesamum indicum. L. (sesame seed oil),Brassica campestris L. (mustard seed oil), and palm kernel oil (PKO). The range of the values obtained are as follows: saponification value (SV): 5.58 - 249.90 mgKOH/g, peroxide value (PV): 0.45 -290.00 mEqO2/kg of sample, acid value (AV): 0.34 - 68.88 mgKOH/g, iodine value (IV): 0.45 - 16.37g I2/100g sample, density (Ds): 908.9 - 919.6kg/m3, viscosity (Vs): 20.58– 77.97 mm2/sec, specific gravity (SG): 0.9089- 0.9196, and refractive index (RI): 1.4578 – 1.4773. The studied characteristics of the oil samples in most cases compared favorably with; FAO/WHO (CODEX Alimentarius) values. There were some observed levels of significant differences in the values at p≤0.05. The data also showed that the oil quality is good and edible inferring from their low AV. Their IV values which were inconsistent with standard values may have been affected by storage conditions and exposure to air and light. On the other hand, their low PV serves as indicators of the presence or high levels of anti-oxidants in the oils. The result of the work confirms these edible oils to be of good quality

A comparative study of characterization and water absorption behaviour of polyester composites with inorganic and organic fibers

Abstract The research deals with fabrication and characterization of h-BN composites with polyester as the matrix material as well as hybrid composites incorporating inorganic as well as organic filler. The inorganic ceramic filler like h-BN tends to enhance the thermal properties and imparting moisture resistant properties whereas organic fillers like Peanut husk increases the strength and stability of the composites. The implications of embedment of h-BN on the thermal conductivity (keff), mechanical characteristics, and morphological parameters are apprehended. It is observed that increase in filler content increases the effective thermal conductivity. With 35 wt% of h-BN the improvement of keff is appreciably elevated to 23.69%.In case of hybrid composites, the keff value decreases to some extent due to insulative property of peanut husk fibers but shows an improvement in mechanical properties with addition of peanut husk fibers. Therefore, thermal conductivity is compromised a little for achieving a balance between physical, mechanical and thermal properties. Though theoretical Rule of Mixture model aids to be well co-correlation to estimate keff for spherical Boron Nitride particles in composites, a better model is proposed for the same. At about filler volume fractions more than 20%, there is a conductivity jump in the composites because of the interaction between Boron Nitride particles and matrix forming conductive networks and this phenomenon occurs at a volume fraction called the percolation threshold. Hence, with higher thermal conductivity and good mechanical properties with very low water absorption, composites with appropriate amount of particulates can be utilized in various fields like heat engine laminates, engine casings, military equipments, fins and heat sinks, printed circuit board substrates etc. where faster heat transfer is a necessity.

Comparative study of preparation and characterization of palladium nanosheets

Comparative study of preparation and characterization of palladium nanosheets

Comparative Study of Rheological Characterization and Classification of Honeys with Their Physicochemical Properties

Comparative Study of Rheological Characterization and Classification of Honeys with Their Physicochemical Properties

A comparative study of surface characterization and corrosion performance properties of laser surface modified biomedical grade nitinol

Laser melting and quick solidification of shape memory alloy surfaces promise to explore the multifunctional capabilities required for enhanced biocompatibility of different implantable medical devices. Before subsequent bio-trial, understanding of the effect of cooling rate vis-à-vis laser fluence on surface characteristics and corrosion protection performance is essential before designing a tailor-made biocompatible surface for various implantable devices. The current study systematically investigates the effect of laser fluence on physical, mechanical and chemical surface characteristics along with corrosion protection performance of the modified surface as compared to bare Nitinol surface. Various phases were prominent on the top surface, namely nickel and titanium-rich phase along with different nickel-titanium intermetallics and nano-structure of titanium oxide, based on varying melting pool recirculation time and cooling rate with laser fluence energy. At low laser fluence up to 4 J/mm2, no significant melting pool were formed and only transformation to the martensitic phase of Nitinol took place on the top surface, which seemed to be highly too much corrosion-prone under simulated body fluid. At moderate laser fluence of 6–8 J/mm2, mostly titanium-rich phases are prominent on the surfaces on account of optimum recirculation of melting pool and subsequent surfacing out of comparably light phase of titanium. Titanium-rich phases on top surface exhibit superior corrosion resistance as compared to all other samples including bare nitinol. However, titanium oxide nano-particles-reinforced martensitic structure is formed under high laser fluence due to over recirculation of molten pool. The modulus of elasticity also varied from 10 to 110 GPa based on top surface formation under different fluence levels, and thus this process can act as a tailor-made controllable pre-treatment process over the traditional coating processes.

A comparative study of characterization of lower Palaeozoic Niutitang shale in northwestern Hunan, China

The lower Palaeozoic Cambrian Niutitang shale and Silurian Longmaxi shale in the upper Yangtze region are the two most favourable marine shales in south China. Great achievements on shale gas development and production have already been made in the Longmaxi shale in southeastern Sichuan (SES). However, to date, economic shale gas potential has not been proved in northwestern Hunan (NWH), which is still a virgin area for shale gas exploration. Based on detailed outcrop investigation, laboratory testing and numerical simulation, the shale gas potential of Niutitang shale were evaluated in this work. Comparisons were also made through vertically diachroneity contrasting with the Longmaxi shale in the NWH area and horizontally isochronic contrasting with Niutitang shale in the SES area. Through analysing the evolution of the palaeoenvironment and palaeotectonics of the period from Niutitang to Longmaxi, it was found that: (1) the NWH Niutitang shale was developed in the hydrothermal continental shelf paleoenvironment, which provided a favourable environment for shale deposition, so the thicker and higher total organic carbon (TOC) shale was largely developed during this time; (2) By the influence of hydrothermal igneous leaching, the element Si formed quartz, which improved the brittleness of the Niutitang shale; (3) Induced by intense tectonic movement, natural fractures were highly developed in the Niutitang shale, which improved the reservoir connectivity; and (4) By comprehensively considering the TOC, reservoir property, and gas retention conditions, the Niutitang shale is a promising target for shale gas development in this area. The results from this work warrant further exploration work in the Niutitang shale in the NWH area.

Comparative study of structural and functional characterization of bran protein concentrates from superfine, fine and coarse rice cultivars

Rice bran protein concentrates prepared from superfine, fine and coarse cultivars were assessed for their physicochemical, structural, functional properties and digestibility. The protein concentrates differed in structural, thermal and functional properties. Rice bran protein concentrate of fine cultivar (F-RBPC) had relatively more β-sheets (42.81%) and less α-helix (15.03%) and β-turns (21.98%) than that of superfine (SF-RBPC) and coarse (C-RBPC) cultivars. Thermal denaturation temperature (Td) was similar for all cultivars, whereas enthalpy of denaturation (ΔH) was high for F-RBPC. Essential and uncharged polar amino acids were the highest in F-RBPC and the lowest in C-RBPC. SF-RBPC had higher digestibility in comparison to F-RBPC and C-RBPC. Surface hydrophobicity, protein solubility and foaming capacity were greatest for F-RBPC. Whereas, SF-RBPC exhibited better foaming stability and emulsion activity and C-RBPC displayed more stable emulsion. Principal component analysis revealed that Td and ΔH were positively correlated with β-sheets content. Foaming capacity and protein solubility were related positively with surface hydrophobicity and negatively charged or uncharged polar amino acids. Emulsion properties were negatively correlated with hydrophobicity. In vitro digestibility of protein was negatively correlated to the ratio of Arginine to Lysine.

Surface modified Li4Ti5O12 by paper templated approach for enhanced interfacial Li+ charge transfer in Li-ion batteries.

The Li4Ti5O12 (LTO) and lithium silicate (LS) surface modified LTO have been demonstrated by a unique paper templated method. Comparative study of structural characterization with electrochemical analysis was demonstrated for pristine and modified Li4Ti5O12. Structural and morphological study shows the existence of the cubic spinel structure with highly crystalline 250–300 nm size particles. The LS modified LTO shows the deposition of 10–20 nm sized LS nanoparticles on cuboidal LTO. Further, X-ray photoelectron spectroscopy (XPS) confirms the existence of Li2SiO3 (LS) in the modified LTO. The electrochemical performance was investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charge–discharge. The modified LTO with 2% LS (LTS2) exhibited excellent rate capability compare to pristine LTO i.e. 182 mA h g−1 specific capacity at a current rate, 50 mA g−1 with remarkable cycling stability up to 1100 cycles at a current rate of 800 mA g−1. The lithium ion full cell of modified LTO with LS as an anode and LiCoO2 as a cathode exhibited a remarkably reversible specific capacity i.e. 110 mA h g−1. Both electronic and ionic conductivities of pristine LTO are observed to be enhanced by incorporation of appropriate amount of LS in LTO due to a larger surface contact at the interface of electrode and electrolyte. More significantly, the versatile paper templated synthesis approach of modified LTO with LS provides densely packed highly crystalline particles. Additionally, it exhibits lower Warburg coefficient and higher Li ion diffusion coefficient which in turn accelerate the interfacial charge transfer process, which is responsible for enhanced stable electrochemical performance. The detailed mechanism is expressed and elaborated for better understanding of enhanced electrochemical performance due to the surface modification.

Fabrication and comparative study of DC and low frequency noise characterization of GaN/AlGaN based MOS-HEMT and HEMT

This work presents the effect of Al mole fraction and gate oxide on the direct current and low frequency noise characterization of GaN/AlGaN high electron mobility transistor (HEMT). Metal–oxide–semiconductor (MOS)-HEMT with SiO2 in the gate stack improved the Id(on)/Id(off) ratio up to more than 8 orders, compared to fabricated HEMT without oxide. It was shown that the gate leakage and isolation leakage suppression efficiency improved dramatically with the gate oxide. Subthreshold swing of MOS-HEMTs with different Al mole fractions (from 20% to 35%) varies slightly from 72 mV/decade to 79 mV/decade. Low frequency noise study revealed the difference in transport mechanism between HEMT and MOS-HEMTs. By using carrier number fluctuation model on the measured data, it was found that the noise is predominantly coming from the surface states. While generation-recombination is very prominent in HEMT, it is very insignificant in both MOS-HEMTs at much higher frequencies. This study reveals that very high number of surface states, assisting the tunneling in Schottky/AlGaN barrier is responsible for unusually high leakage and higher noise level in HEMT without oxide. Leakage level is improved from mA/mm range for HEMT to pA/mm range for MOS-HEMTs. Leakage suppression improvement and minimization of noise level can be mainly attributed by to high quality SiO2. Hooge's constant was on the order of 5–6 × 10−3, which is 5 × 10−2 for HEMT without oxide.

Green synthesis of silver nanoparticles using Allium cepa and Allium sativum extract: A comparative characterization study

Green synthesis of silver nanoparticles using Allium cepa and Allium sativum extract: A comparative characterization study

Comparative Study of Single and Double Quantum Well AlGaN/GaN HEMT Structures for High Power GHz Frequency Application

The aim of this work is to simulate and analyze the performance of single and double quantum well AlGaN/GaN HEMT (High Electron Mobility Transistor) structures for high power GHz frequency application with the variation of gate length, spacer layer thickness and doping layer thickness. To study the effect of these variations we use Atlas Tcad-Silvaco numerical simulation software. The drift-diffusion model has been taken for simulating the proposed device. We use sapphire as a substrate for this structure. We have performed the comparative characterization study of 2-DEG (Two Dimensional Electron Gas), threshold voltage (Vth) and transconductance (gm) of the double quantum with single quantum well HEMT structure. As a result of this comparison the double quantum well HEMT structure has been seen to exhibit more sensitive to these parameters. Thus, optimization of the gate length, donor layer thickness and spacer layer thickness of double quantum well HEMT structure is crucial.

Metabolic Characterization of Acutely Isolated Hippocampal and Cerebral Cortical Slices Using [U-13C]Glucose and [1,2-13C]Acetate as Substrates.

Brain slice preparations from rats, mice and guinea pigs have served as important tools for studies of neurotransmission and metabolism. While hippocampal slices routinely have been used for electrophysiology studies, metabolic processes have mostly been studied in cerebral cortical slices. Few comparative characterization studies exist for acute hippocampal and cerebral cortical slices, hence, the aim of the current study was to characterize and compare glucose and acetate metabolism in these slice preparations in a newly established incubation design. Cerebral cortical and hippocampal slices prepared from 16 to 18-week-old mice were incubated for 15-90min with unlabeled glucose in combination with [U-13C]glucose or [1,2-13C]acetate. Our newly developed incubation apparatus allows accurate control of temperature and is designed to avoid evaporation of the incubation medium. Subsequent to incubation, slices were extracted and extracts analyzed for 13C-labeling (%) and total amino acid contents (µmol/mg protein) using gas chromatography-mass spectrometry and high performance liquid chromatography, respectively. Release of lactate from the slices was quantified by analysis of the incubation media. Based on the measured 13C-labeling (%), total amino acid contents and relative activity of metabolic enzymes/pathways, we conclude that the slice preparations in the current incubation apparatus exhibited a high degree of metabolic integrity. Comparison of 13C-labeling observed with [U-13C]glucose in slices from cerebral cortex and hippocampus revealed no significant regional differences regarding glycolytic or total TCA cycle activities. On the contrary, results from the incubations with [1,2-13C]acetate suggest a higher capacity of the astrocytic TCA cycle in hippocampus compared to cerebral cortex. Finally, we propose a new approach for assessing compartmentation of metabolite pools between astrocytes and neurons using 13C-labeling (%) data obtained from mass spectrometry. Based on this approach we suggest that cellular metabolic compartmentation in hippocampus and cerebral cortex is very similar.

Comparative study of isolation, expansion and characterization of epithelial cells

Background aimsThe human epithelial cells (EPCs) have been identified as the essential element for the regeneration of skin construct for burns, wounds and various tissue engineer–based products. MethodsIn this study, the isolation, expansion and characterization of EPCs from various sources such as juvenile foreskin (JSK), buccal mucosa (BM), penile skin (PS) and urothelium (UR) in serum-free and xeno-free EpiLife media were evaluated. ResultsThe growth kinetics study revealed that EPCs from JSK and BM had notably higher growth rates compared with the others. Overall, the EPCs from all sources retained basic morphological characteristics and the functional characteristics such as Pan Cytokeratin (AE1/AE3). In addition, the cryopreservation stability of EPCs was accessed for post-thaw viability and found to be greater than 80% at 1 year of storage, but demonstrated reduced cell recovery (51%) at the second year in fetal bovine serum–free cryopreservation media. ConclusionsOur result suggests that the EPCs from four cell sources can be grown in feeder-free, serum-free and xeno-free systems using commercially available EpiLife medium without losing epithelial cell characteristics even after passage 4. However, its suitability for clinical application must be accessed by preclinical and clinical studies.

Assessing Analytical Similarity of Proposed Amgen Biosimilar ABP 501 to Adalimumab.

BackgroundABP 501 is being developed as a biosimilar to adalimumab. Comprehensive comparative analytical characterization studies have been conducted and completed.ObjectiveThe objective of this study was to assess analytical similarity between ABP 501 and two adalimumab reference products (RPs), licensed by the United States Food and Drug Administration (adalimumab [US]) and authorized by the European Union (adalimumab [EU]), using state-of-the-art analytical methods.MethodsComprehensive analytical characterization incorporating orthogonal analytical techniques was used to compare products. Physicochemical property comparisons comprised the primary structure related to amino acid sequence and post-translational modifications including glycans; higher-order structure; primary biological properties mediated by target and receptor binding; product-related substances and impurities; host-cell impurities; general properties of the finished drug product, including strength and formulation; subvisible and submicron particles and aggregates; and forced thermal degradation.ResultsABP 501 had the same amino acid sequence and similar post-translational modification profiles compared with adalimumab RPs. Primary structure, higher-order structure, and biological activities were similar for the three products. Product-related size and charge variants and aggregate and particle levels were also similar. ABP 501 had very low residual host-cell protein and DNA. The finished ABP 501 drug product has the same strength with regard to protein concentration and fill volume as adalimumab RPs. ABP 501 and the RPs had a similar stability profile both in normal storage and thermal stress conditions.ConclusionBased on the comprehensive analytical similarity assessment, ABP 501 was found to be similar to adalimumab with respect to physicochemical and biological properties.

Comparative study of characterization and utilization of corncob ashes from gasification process and combustion process

In the present study, fly ashes were obtained as a byproduct respectively from the processing of corncob in a gasification plant and from the combustion of corncob in a muffle furnace. The aim of this study is to characterize the basic properties of the fly ashes from gasification process and combustion process whilst comparing the results between these two types of solid residues to evaluate their potential applications. The results indicate that the CCA from gasification is more suitable to be used as a raw material for activated carbon owing to its larger specific surface area and higher carbon content compared with the CCA from combustion. With higher concentrations of K, Ca, and P, the CCA from gasification process is more bioavailable than CCA from combustion to be soil amendment. SEM images show that these CCA particles are agglomerated and irregular in shapes. The external surface of agglomerated particles is covered with potassium chloride. The influence of ashing temperature on ash morphology and agglomeration behavior is obvious, and the agglomeration tendency and melting degree are enhanced at high temperatures. Thermal analysis reveals the stepwise mechanism of decomposition for CCA. Specifically, the combustion CCA is more suitable for use as a pozzolan in blended cement concrete compared with the gasification CCA. Also, all ash samples with high silica content are suitable for ceramics.

A Comparative Characterization Study of Molybdenum Oxide Thin Films Grown Using Femtosecond and Nanosecond Pulsed Laser Deposition

ABSTRACTGroup 6 transition metal oxide thin films are in large demand for photocatalysis, heterogeneous catalysis, fuel cell, battery and electronic applications. Pulsed laser deposition offers an inexpensive method for the preparation of nanostructured thin films that may be suitable for heterogeneous catalysis. We have synthesized molybdenum oxide thin films using two types of pulsed laser deposition (PLD). The first method utilizes femtosecond laser-based PLD (f-PLD) while the second method uses an excimer (nanosecond) laser-based PLD (n-PLD). The PLD films have been deposited using f-PLD and, separately, n-PLD on glass and silicon substrates and subsequently annealed to 450 °C for up to 20 hours in air using a Linkam stage. SEM, XRD and Raman spectroscopic characterization shows that the f-PLD films are substantially more textured and partially crystalline prior to annealing whereas the n-PLD-grown thin films are much smoother and predominantly amorphous. A 3-dimensional nano-crystalline structure is evident in the post-annealed f-PLD synthesized thin films, which is desirable for catalytic applications. XPS elemental analysis shows that the stoichiometry of the f-PLD and n-PLD thin films is consistent with the presence of MoO2 and MoO3. Our results are discussed in terms of thin film growth models suitable for f-PLD vs n-PLD.

Comparative characterization study of pure and glycine doped potassium thiourea chloride crystal for laser frequency conversion applications

In current study doping of glycine (G) in potassium thiourea chloride (PTC) crystal has been firstly achieved and glycine doped PTC (G-PTC) crystal has been grown by slow solution evaporation technique. The unit cell parameters of crystals have been determined by means of single crystal X-ray diffraction technique. The functional groups of pure and G-PTC crystal have been identified using Fourier transform infrared analysis. In UV–visible studies, the increased optical transparency of G-PTC crystal has been measured within 200–900nm and the optical constants have been determined using the transmittance data. The Kurtz and Perry test has been performed to confirm the enhancement in second harmonic generation (SHG) efficiency of G-PTC crystal as compared to KDP and PTC crystal. The temperature dependent dielectric analysis has been carried out to investigate the dielectric constant and dielectric loss of grown crystal. The thermal stability of the grown crystal has been determined using the thermogravimetric analysis.

Comparative study of organic matter chemical characterization using negative and positive mode electrospray ionization ultrahigh-resolution mass spectrometry.

The chemical characterization of dissolved organic matter (DOM) is critical for understanding carbon sequestration processes in soils. This work evaluated the use of electrospray ionization in both negative ion mode (ESI-) and positive ion mode (ESI+) for the characterization of DOM extracted from nine terrestrial sources using Fourier transform ion cyclotron mass spectrometry (FT-ICR-MS). The compositing of the peaks from ESI- to ESI+ modes increased the total assigned formulas from 23 to 63% as compared to the traditional use of ESI- alone for DOM characterization. In general, there was a preferential increase in the number of assignments for the aliphatic and carbohydrate-like DOM components in the ESI+ mode. The soil-extracted DOM specifically exhibited greater increases in the aliphatic and carbohydrate-like DOM components with the combined use of ESI- and ESI+ modes likely due to the greater presence of aromatic DOM molecules that suppressed the ionization of these entities in ESI- mode. On the basis of these findings, we show that improved characterization of DOM is possible through the combined use of ESI- and ESI+ modes for FT-ICR-MS analysis, especially for samples rich in condensed aromatic and aromatic molecules.

Comparative study of preparation, characterization and anticandidal activities of a chitosan silver nanocomposite (CAgNC) compared with low molecular weight chitosan (LMW-chitosan)

A chitosan-silver nanocomposite (CAgNC) was synthesized in a green manner using low molecular weight chitosan (LMW-chitosan) and silver nitrate without applying external chemical reducing agents.