Abstract: Novel polystrene-bound Schiff bases and their Pt(IV)
complexes have been prepared from condensation reaction of
polystyrene-A-NH2 with 2-hydroxybenzaldehyde and 5-fluoro-3-
bromo-2-hydroxybenzaldehyde. The structures of Pt(IV) complexes
with polystyrene including Schiff bases have been determined by
elemental analyses, magnetic susceptibility, IR, 1H-NMR, UV-vis,
TG/DTA and AAS. The antibacterial and antifungal activities of the
synthesized compounds have been studied by the well-diffusion
method against some selected microorganisms: (Bacillus cereus spp.,
Listeria monocytogenes 4b, Micrococcus luteus, Staphylococcus
aureus, Staphylococcus epidermis, Brucella abortus, Escherichia
coli, Pseudomonas putida spp., Shigella dysenteria type 10,
Salmonella typhi H).
Abstract: In this paper, an automatic determination algorithm for nuclear magnetic resonance (NMR) spectra of the metabolites in the living body by magnetic resonance spectroscopy (MRS) without human intervention or complicated calculations is presented. In such method, the problem of NMR spectrum determination is transformed into the determination of the parameters of a mathematical model of the NMR signal. To calculate these parameters efficiently, a new model called modified Hopfield neural network is designed. The main achievement of this paper over the work in literature [30] is that the speed of the modified Hopfield neural network is accelerated. This is done by applying cross correlation in the frequency domain between the input values and the input weights. The modified Hopfield neural network can accomplish complex dignals perfectly with out any additinal computation steps. This is a valuable advantage as NMR signals are complex-valued. In addition, a technique called “modified sequential extension of section (MSES)" that takes into account the damping rate of the NMR signal is developed to be faster than that presented in [30]. Simulation results show that the calculation precision of the spectrum improves when MSES is used along with the neural network. Furthermore, MSES is found to reduce the local minimum problem in Hopfield neural networks. Moreover, the performance of the proposed method is evaluated and there is no effect on the performance of calculations when using the modified Hopfield neural networks.
Abstract: In the last decade, carbohydrates have attracted great
attention as renewable resources for the chemical industry.
Carbohydrates are abundantly found in nature in the form of
monomers, oligomers and polymers, or as components of
biopolymers and other naturally occurring substances. As natural
products, they play important roles in conferring certain physical,
chemical, and biological properties to their carrier molecules.The
synthesis of this particular carbohydrate glycomonomer is part of our
work to obtain biodegradable polymers. Our current paper describes
the synthesis and characterization of a novel carbohydrate
glycomonomer starting from D-glucose, in several synthesis steps,
that involve the protection/deprotection of the D-glucose ring via
acetylation, tritylation, then selective deprotection of the aromaticaliphatic
protective group, in order to obtain 1,2,3,4-tetra-O-acetyl-
6-O-allyl-β-D-glucopyranose. The glycomonomer was then obtained
by the allylation in drastic conditions of 1,2,3,4-tetra-O-acetyl-6-Oallyl-
β-D-glucopyranose with allylic alcohol in the presence of
stannic chloride, in methylene chloride, at room temperature. The
proposed structure of the glycomonomer, 2,3,4-tri-O-acetyl-1,6-di-
O-allyl-β-D-glucopyranose, was confirmed by FTIR, NMR and
HPLC-MS spectrometry. This glycomonomer will be further
submitted to copolymerization with certain acrylic or methacrylic
monomers in order to obtain competitive plastic materials for
applications in the biomedical field.
Abstract: Alpinia galanga is rhizome, generally known as
Greater galangal and is selected for isolation of newer constituents
accountable for various therapeutic activities. Present study is
intended to isolate glycoside from Alpinia galanga rhizomes. Alpinia
galanga methanolic extract was column chromatograph and eluted
with ethyl acetate-methanol (99:1) to isolate compound β-Sitosterol
Diarabinoside. Herein, the isolation and structural elucidation of new
compound is described. Chemical investigation of methanolic extract
of rhizomes of Alpinia galanga furnished a new compound β-
Sitosterol Diarabinoside. The IR, NMR and MASS investigations of
isolated compound confirmed its structure as β-Sitosterol
Diarabinoside, which is isolated for the first time from a medicinal
plant or any synthetic source.
Abstract: Bioinformatics and Cheminformatics use computer as disciplines providing tools for acquisition, storage, processing, analysis, integrate data and for the development of potential applications of biological and chemical data. A chemical database is one of the databases that exclusively designed to store chemical information. NMRShiftDB is one of the main databases that used to represent the chemical structures in 2D or 3D structures. SMILES format is one of many ways to write a chemical structure in a linear format. In this study we extracted Antimicrobial Structures in SMILES format from NMRShiftDB and stored it in our Local Data Warehouse with its corresponding information. Additionally, we developed a searching tool that would response to user-s query using the JME Editor tool that allows user to draw or edit molecules and converts the drawn structure into SMILES format. We applied Quick Search algorithm to search for Antimicrobial Structures in our Local Data Ware House.
Abstract: Presence of phytosterol compound in Durian seed
(Durio zibethinus) or known as King of fruits has been discovered
from screening work using reagent test. Further analysis work has
been carried out using mass spectrometer in order to support the
priliminary finding. Isolation and purification of the major
phytosterol has been carried out using an open column
chromatography. The separation was monitored using thin layer
chromatography (TLC). Major isolated compounds and purified
phytosterol were identified using mass spectrometer and nuclear
magnetic resonance (NMR). This novel finding could promote
utilization of durian seeds as a functional ingredient in food products
through production of standardized extract based on phytosterol
content.
Abstract: The field of polymeric biomaterials is very important
from the socio-economical viewpoint. Synthetic carbohydrate
polymers are being increasingly investigated as biodegradable,
biocompatible and biorenewable materials. The aim of this study was
to synthesize and characterize some derivatives based on D-mannose.
D-mannose was chemically modified to obtain 1-O-allyl-2,3:5,6-di-
O-isopropylidene-D-mannofuranose and 1-O-(2-,3--epoxy-propyl)-
2,3:5,6-di-O-isopropylidene-D-mannofuranose.
The chemical structure of the resulting compounds was
characterized by FT-IR and NMR spectroscopy, and by HPLC-MS.
Abstract: The first and basic cause of the failure of concrete is repeated freezing (thawing) of moisture contained in the pores, microcracks, and cavities of the concrete. On transition to ice, water existing in the free state in cracks increases in volume, expanding the recess in which freezing occurs. A reduction in strength below the initial value is to be expected and further cycle of freezing and thawing have a further marked effect. By using some experimental parameters like nuclear magnetic resonance variation (NMR), enthalpy-temperature (or heat capacity) variation, we can resolve between the various water states and their effect on concrete properties during cooling through the freezing transition temperature range. The main objective of this paper is to describe the principal type of water responsible for the reduction in strength and structural damage (frost damage) of concrete following repeated freeze –thaw cycles. Some experimental work was carried out at the institute of cryogenics to determine what happens to water in concrete during the freezing transition.
Abstract: The polyfunctional and highly reactive bio-polymer,
the chitosan was first regioselectively converted into dialkylated
chitosan using dimsyl anionic solution(NaH in DMSO) and
bromodecane after protecting amino groups by phthalic anhydride.
The dibenzo-18-crown-6-ether, on the other hand, was converted into
its carbonyl derivatives via Duff reaction prior to incorporate into
chitosan by Schiff base formation. Thus formed diformylated
dibenzo-18-crown-6-ether was condensed with lipophilic chitosan to
prepare the novel solvent extraction reagent. The products were
characterized mainly by IR and 1H-NMR. Hence, the multidentate
crown ether-embedded polyfunctional bio-material was tested for
extraction of Pd(II) and Pt(IV) in aqueous solution.
Abstract: The characterization of κ-carrageenan could provide a
better understanding of its functions in biological, medical and
industrial applications. Chemical and physical analyses of
carrageenan from seaweeds, Euchema cottonii L., were done to offer
information on its properties and the effects of Co-60 γ-irradiation on
its thermochemical characteristics. The structural and morphological
characteristics of κ-carrageenan were determined using scanning
electron microscopy (SEM) while the composition, molecular weight
and thermal properties were determined using attenuated total
reflectance Fourier transform infrared spectroscopy (ATR-FTIR), gel
permeation chromatography (GPC), thermal gravimetric analysis
(TGA) and differential scanning calorimetry (DSC). Further chemical
analysis was done using hydrogen-1 nuclear magnetic resonance (1H
NMR) and functional characteristics in terms of biocompatibility
were evaluated using cytotoxicity test.
Abstract: Hydrate phase equilibria for the binary CO2+water and
CH4+water mixtures in silica gel pore of nominal diameters 6, 30, and
100 nm were measured and compared with the calculated results based
on van der Waals and Platteeuw model. At a specific temperature,
three-phase hydrate-water-vapor (HLV) equilibrium curves for pore
hydrates were shifted to the higher-pressure condition depending on
pore sizes when compared with those of bulk hydrates. Notably,
hydrate phase equilibria for the case of 100 nominal nm pore size were
nearly identical with those of bulk hydrates. The activities of water in
porous silica gels were modified to account for capillary effect, and
the calculation results were generally in good agreement with the
experimental data. The structural characteristics of gas hydrates in
silica gel pores were investigated through NMR spectroscopy.
Abstract: The aim of this study is evaluating the antinociceptive
and anti-inflamatory activity of Geum kokanicum. After
determination total extract LD50, different doses of extract were
chosen for intrapritoneal injections. In inflammation test, male NMRI
mice were divided into 6 groups: control (normal saline), positive
control (Dexamethasone 15mg/kg), and total extract (0.025, 0.05,
0.1, and 0.2 gr/kg). The inflammation was produced by xyleneinduced
edema. In order to evaluate the antinociceptive effect of total
extract, formalin test was used. Mice were divided into 6 groups:
control, positive control (morphine 10mg/kg), and 4 groups which
received total extract. Then they received Formalin. The animals
were observed for the reaction to pain. Data were analyzed using
One-way ANOVA followed by Tukey-Kramer multiple comparison
test. LD50 was 1 gr/kg. Data indicated that 0.5,0.1 and 0.2 gr/kg
doses of total extract have particular antinociceptive and antiinflammatory
effects in a comparison with control (P
Abstract: Hydrothermally synthesized high silica borosilicates
with the MFI structure was subjected to several characterization
techniques. The effect of boron on the structure and acidity of
HZSM-5 catalyst were studied by XRD, SEM, N2 adsorption, solid
state NMR, NH3-TPD. It was confirmed that boron had entered the
framework in the boron samples. The results also revealed that strong
acidity was weakened and weak acidity was strengthened by the
boron added zeolite framework compared with parent catalyst. The
catalytic performance was carried out in a fixed bed at 460°C for
methanol to propylene (MTP) reaction. The results of MTP reaction
showed a great increment of the propylene selectivity and excellent
stability for the B-HZSM-5. The catalyst exhibited about 81%
selectivity to C2
= - C4
= olefins with 40% selectivity of propylene as
major component at near 100% methanol conversion, and the stable
performance in the studied period was 100h.
Abstract: This study has investigated the antidiabetic and
antioxidant potential of Pseudovaria macrophylla bark extract on
streptozotocin–nicotinamide induced type 2 diabetic rats. LCMSQTOF
and NMR experiments were done to determine the chemical
composition in the methanolic bark extract. For in vivo experiments,
the STZ (60 mg/kg/b.w, 15 min after 120 mg/kg/1 nicotinamide, i.p.)
induced diabetic rats were treated with methanolic extract of
Pseuduvaria macrophylla (200 and 400 mg/kg·bw) and
glibenclamide (2.5 mg/kg) as positive control respectively.
Biochemical parameters were assayed in the blood samples of all
groups of rats. The pro-inflammatory cytokines, antioxidant status
and plasma transforming growth factor βeta-1 (TGF-β1) were
evaluated. The histological study of the pancreas was examined and
its expression level of insulin was observed by
immunohistochemistry. In addition, the expression of glucose
transporters (GLUT 1, 2 and 4) were assessed in pancreas tissue by
western blot analysis. The outcomes of the study displayed that the
bark methanol extract of Pseuduvaria macrophylla has potentially
normalized the elevated blood glucose levels and improved serum
insulin and C-peptide levels with significant increase in the
antioxidant enzyme, reduced glutathione (GSH) and decrease in the
level of lipid peroxidation (LPO). Additionally, the extract has
markedly decreased the levels of serum pro-inflammatory cytokines
and transforming growth factor beta-1 (TGF-β1). Histopathology
analysis demonstrated that Pseuduvaria macrophylla has the
potential to protect the pancreas of diabetic rats against peroxidation
damage by downregulating oxidative stress and elevated
hyperglycaemia. Furthermore, the expression of insulin protein,
GLUT-1, GLUT-2 and GLUT-4 in pancreatic cells was enhanced.
The findings of this study support the anti-diabetic claims of
Pseudovaria macrophylla bark.
Abstract: A model of (4, 4) single-walled boron-nitride nanotube as a representative of armchair boron-nitride nanotubes studied. At first the structure optimization performed and then Nuclear Magnetic Resonance parameters (NMR) by Density Functional Theory (DFT) method at 11B and 15N nuclei calculated. Resulted parameters evaluation presents electrostatic environment heterogeneity along the nanotube and especially at the ends but the nuclei in a layer feel the same electrostatic environment. All of calculations carried out using Gaussian 98 Software package.
Abstract: Copolymerization of ethylene with 1-hexene was
carried out using two ansa-fluorenyl titanium derivative complexes.
The substituent effect on the catalytic activity, monomer reactivity
ratio and polymer property was investigated. It was found that the
presence of t-Bu groups on fluorenyl ring exhibited remarkable
catalytic activity and produced polymer with high molecular weight.
However, these catalysts produce polymer with narrow molecular
weight distribution, indicating the characteristic of single-site
metallocene catalyst. Based on 13C NMR, we can observe that
monomer reactivity ratio was affected by catalyst structure. The rH
values of complex 2 were lower than that of complex 1 which might
be result from the higher steric hindrance leading to a reduction of 1-
hexene insertion step.
Abstract: In this paper, we proposed the distribution of mesh
normal vector direction as a feature descriptor of a 3D model. A
normal vector shows the entire shape of a model well. The
distribution of normal vectors was sampled in proportion to each
polygon's area so that the information on the surface with less surface
area may be less reflected on composing a feature descriptor in order
to enhance retrieval performance. At the analysis result of ANMRR,
the enhancement of approx. 12.4%~34.7% compared to the existing
method has also been indicated.
Abstract: Polylactic acid-g-polyvinyl acetate (PLLA-g-PVAc)
was used as a compatibilizer for 50/50 starch/PLLA blend. PLLA-g-
PVAc with different mol% of PVAc contents were prepared by
grafting PVAc onto PLLA backbone via free radical polymerization
in solution process. Various conditions such as type and the amount
of initiator, monomer concentration, polymerization time and
temperature were studied. Results showed that the highest mol% of
PVAc grafting (16 mol%) was achieved by conducting graft
copolymerization in toluene at 110°C for 10 h using DCP as an
initiator. Chemical structure of the PVAc grafted PLLA was
confirmed by 1H NMR. Blending of modified starch and PLLA in the
presence compatibilizer with different amounts and mol% PVAc was
acquired using internal mixer at 160°C for 15 min. Effects of PVAc
content and the amount of compatibilizer on mechanical properties of
polymer blend were studied. Results revealed that tensile strength and
tensile modulus of polymer blend with higher PVAc grafting content
compatibilizer showed better properties than that of lower PVAc
grafting content compatibilizer. The amount of compatibilizer was
found optimized in the range of 0.5-1.0 Wt% depending on the mol%
PVAc.
Abstract: An efficient parallel form in digital signal processor can improve the algorithm performance. The butterfly structure is an important role in fast Fourier transform (FFT), because its symmetry form is suitable for hardware implementation. Although it can perform a symmetric structure, the performance will be reduced under the data-dependent flow characteristic. Even though recent research which call as novel memory reference reduction methods (NMRRM) for FFT focus on reduce memory reference in twiddle factor, the data-dependent property still exists. In this paper, we propose a parallel-computing approach for FFT implementation on digital signal processor (DSP) which is based on data-independent property and still hold the property of low-memory reference. The proposed method combines final two steps in NMRRM FFT to perform a novel data-independent structure, besides it is very suitable for multi-operation-unit digital signal processor and dual-core system. We have applied the proposed method of radix-2 FFT algorithm in low memory reference on TI TMSC320C64x DSP. Experimental results show the method can reduce 33.8% clock cycles comparing with the NMRRM FFT implementation and keep the low-memory reference property.
Abstract: Five lignin samples were fractionated with
Acetone/Water mixtures and the obtained fractions were subjected to
extensive structural characterization, including Fourier Transform
Infrared (FT-IR), Gel permeation Chromatography (GPC) and
Phosphorus-31 NMR spectroscopy (31P-NMR). The results showed
that for all studied lignins the solubility increases with the increment
of the acetone concentration. Wheat straw lignin has the highest
solubility in 90/10 (v/v) Acetone/Water mixture, 400 mg lignin being
dissolved in 1 mL mixture. The weight average molecular weight of
the obtained fractions increased with the increment of acetone
concentration and thus with solubility. 31P-NMR analysis based on
lignin modification by reactive phospholane into phosphitylated
compounds was used to differentiate and quantify the different types
of OH groups (aromatic, aliphatic, and carboxylic) found in the
fractions obtained with 70/30 (v/v) Acetone/Water mixture.