Sharif Digital Repository

A 1H-NMR procedure based on an analysis of its data by a multivariate calibration method was conducted for the simultaneous determination of theophylline and caffeine in synthetic and real samples. Partial least squares regression (PLS) was chosen as the calibration method. The methyl signals of theophilline at 3.36 and 3.54 ppm that overlapped with those of caffeine were significant characteristics which were employed in this study for their analyses. The proposed method was successfully applied to recovery studies of theophylline and caffeine from real tablet samples  

Teratozoospermia is one of conditions that can cause male infertility. The mechanism of teratozoospermia remains unclear. The knowledge of the metabolites in human seminal plasma (HSP) is meaningful for the pathological study of teratozoospermia. Analysis of changed metabolites in HSP can help understand the cellular mechanism, find the novel biomarkers and subsequently design a diagnosis test. In this study, the analysis of samples performed by proton nuclear magnetic resonance spectroscopy (1H NMR spectroscopy) to identify the various metabolites, with the aim of finding metabolic profiles and biomarkers related to male infertility. Eighteen de-regulated metabolites were identified in... 

Crohn's disease and celiac disease belong to a group of autoimmune conditions that affect the digestive system, specifically the small intestine. They both attack the digestive tract and share many symptoms. Thus, the discovery of proper methods would be a major step toward differentiating celiac disease from Crohn's disease. The aim of this study was to search for the metabolic biomarkers to differentiate between these two diseases. Proton nuclear magnetic resonance spectroscopy (1H NMR) was employed as the metabolic profiling method to look for serum metabolites that differentiate between celiac disease and Crohn's disease. Classification of celiac disease and Crohn's disease was done... 

Parkinson's disease (PD) is a neurodegenerative disease, which is not easily diagnosed using clinical tests and the discovery of proper methods would be a major step towards a successful diagnosis. In the present study, we employed metabolic profiling using proton nuclear magnetic resonance spectroscopy to find metabolites in serum, which are helpful for the diagnosis of PD. Classification of PD and healthy subject was done using random forest. Serum levels of selenium measured by atomic absorption spectrometry in PD group were lower than the serum selenium levels in the control group. The metabolites causing selenium changes in PD patients were identified using random forest, and a model... 

Multiple sclerosis (MS) is a nervous system disease that affects the fatty myelin sheaths around the axons of the brain and spinal cord, leading to demyelination and a broad range of signs and symptoms. MS can be difficult to diagnose because its signs and symptoms may be similar to other medical problems. To find out which metabolites in serum are effective for the diagnosis of MS, we utilized metabolic profiling using proton nuclear magnetic resonance spectroscopy (1H-NMR). Random forest (RF) was used to classify the MS patients and healthy subjects. Atomic absorption spectroscopy was used to measure the serum levels of selenium. The results showed that the levels of selenium were lower in... 

Reaction of the electron-rich complex cis-[Pt(p-Me-C6H4)2(SMe2)2] with 2,2′-bipyridine N-oxide, O-bpy occurred by rollover cyclometalation to afford complex [Pt(O-bpy)(p-Me-C6H4)(SMe2)], 1. The obtained complex was characterized using NMR spectroscopy and its solid state structure was determined by the single crystal X-ray diffraction method. The reaction of 1 with seven diphosphine ligands, 1,1-bis(diphenylphosphino)methane (dppm), 1,2-bis(diphenylphosphino)ethane (dppe), 1,3-bis(diphenylphosphino)propane (dppp), 1,4-bis(diphenylphosphino)butane (dppb), N,N-bis(diphenylphosphino)amine (dppa), 1,2-bis(diphenylphosphino)benzene (dppbz) and 1,1′-bis(diphenylphosphino)ferrocene (dppf), in... 

Eight new chitin derivatives have been synthesized via SN2 reaction of primary and secondary amines with tosylchitin. The products were characterized using FTIR and 1H NMR spectroscopy. A degree of substitution ∼ 1 was achieved through this process. These materials are soluble in water at room temperature, which enable their further applications in the future. © 2007 WILEY-VCH Verlag GmbH & Co. KGaA  

The symmetrical and unsymmetrical Schiff base complexes of VO(IV) and Mn(III) derived from 2,2′-diaminobiphenyl and derivatives of salicylaldehyde and 1-hydroxy-2-napnthaldehyde have been synthesized and characterized by elemental analysis, NMR, infrared and electronic absorption spectroscopies, and conductivity measurements. The reaction of the ligands with oxovanadium(IV) was found to be kinetically unfavored, probably due to the small ionic radius of the metal ion, which is not in accordance with the cavity size of the ligands. Copyright © 2005 Taylor & Francis, Inc  

Batch culture of Azohydromonas lata was investigated for the production of intracellular poly-b-hydroxybutyrate (PHB). In order to determine the C:N value of the culture media for maximizing the microbial productivity of PHB, different concentrations of glucose and ammonium chloride were used as carbon and nitrogen sources, respectively. The optimal temperature and shaking rate was obtained at 30_C and 180 rpm, respectively. The maximum intracellular PHB concentration obtained was 5.09 g/l, which was 20% (w/w) of the cell dry weight (CDW) after 72 h. Also, the synthesis of PHB was growth associated with the C:N ratio of 153.71. The maximum calculated Yp/s was 0.212 (gr/gr) and the specific... 

The reaction of 15-18 membered benzodiazacrown ethers with salicylaldehyde afforded n-membered O2N2-donor macrocyclic ligands mounted with 1,3-diazacyclohexane subrings (1-4) in high yields. The products were characterized by FT-IR, 1H, 13C NMR spectroscopy, elemental analyses, and single crystal X-ray studies. The solid state structures revealed strong intramolecular hydrogen bonding between the pendant phenolic group and the tertiary nitrogen of the corresponding macroring  

The anomeric carbon chemical shifts of α-, β- and γ-cyclodextrin in solution were studied experimentally and theoretically by NMR and two-layer ONIOM2 (B3LYP/6-31G*-GIAO: HF/6-31G*-GIAO) variant. The dependence between the anomeric carbon chemical shift and the glycosidic bond φ and ψ dihedral angles in d-Glcp-d-Glcp disaccharides with and (1 → 4) linkages in α-configurations were computed by Gauge-Including Atomic Orbital (GIAO) ab initio and ONIOM in water solvent using PCM methods. Complete chemical shift surfaces versus φ and ψ for this disaccharide were computed. We also present empirical formulas of the form 13C δ = f(φ, ψ) obtained by fitting the ab initio data to trigonometric series... 

In this paper, using of fault tolerant techniques are studied and experimented in speech recognition systems to make these systems robust to noise. Recognizer redundancy is implemented to utilize the strengths of several recognition methods that each one has acceptable performance in a specific condition. Duplication-with-comparison and NMR methods are experimented with majority and plurality voting on a telephony Persian speech-enabled IVR system. Results of evaluations present two promising outcomes, first, it improves the performance considerably; second, it enables us to detect the outputs with low confidence. © 2008 IEEE  

Tetraphenylthiophene diamine (TPTDA) was prepared through a modified three-step route to achieve an improved overall yield. TPTDA reacted with succinic, adipic, suberic, sebasic, and fumaric acids via the Yamazaki phosphorylation method to yield novel partially aromatic polyamides (TPT series). A counterpart polyamide series based on p-phenylene diamine (Ph series) was also synthesized under the same conditions. All of the polymers were characterized by means of spectrochemical (Fourier transform infrared spectroscopy. 1H-nuclear magnetic resonance (NMR), and 13C-NMR) and thermal (differential scanning calorimetry and thermogravimetric) methods of analysis. Solubility of TPT polyamides was... 

The present study was designed to search for metabolic biomarkers and their correlation with serum zinc in Crohn's disease patients. Crohn's disease (CD) is a form of inflammatory bowel disease that may affect any part of the gastrointestinal tract and can be difficult to diagnose using the clinical tests. Thus, introduction of a novel diagnostic method would be a major step towards CD treatment.Proton nuclear magnetic resonance spectroscopy ( 1H NMR) was employed for metabolic profiling to find out which metabolites in the serum have meaningful significance in the diagnosis of CD. CD and healthy subjects were correctly classified using random forest methodology. The classification model for... 

Solid state 13C and 15N chemical shifts of uracil and imidazole have been calculated using a 2-layer ONIOM approach at 32 levels of theory. The effect of electron correlation between two layers has been investigated by choosing two different kinds of layer selection. Factorial design has been applied as a multivariate technique to analyze the effect of wave function and layer selection on solid state 13C and 15N chemical shifts calculations. PBEPBE/6-311+G(d,p) was recommended as an optimally selected level of theory for high layer in both models. It is illustrated that considering the electron correlation of two layers of ONIOM models is important factor to calculate solid state 15N... 

Sulfur Mustard (SM) is a potent alkylating agent and its effects on cells and tissues are varied and complex. Due to limitations in the diagnostics of sulfur mustard exposed individuals (SMEIs) by noninvasive approaches, there is a great necessity to develop novel techniques and biomarkers for this condition. We present here the first nuclear magnetic resonance (NMR) and gas chromatography-mass spectrometry (GC/MS) metabolic profiling of serum from and healthy controls to identify novel biomarkers in blood serum for better diagnostics. Of note, SMEIs were exposed to SM 30 years ago and that differences between two groups could still be found. Pathways in which differences between SMEIs and... 

Vacuum residue cracking has been successfully conducted under supercritical water condition in presence of various metal oxide nanocalysts, namely NiO, CuO, ZnO, Co2O3, and Cr2O3 synthesized at supercritical water. The cracking experiments were carried out at 450 °C. Three species of cracking: maltene, asphaltene, and coke were then weighed and their corresponding speciation was defined. Gas chromatography-mass spectrometry (GC–MS), nuclear magnetic resonance spectroscopy (NMR), thermogravimetric analysis (TGA), and elemental analysis (CHNS) tests were utilized to prove the performance of upgrading reactions. It was revealed that NiO showed the best performance among other catalyst, in which... 

13C chemical shieldings and 14N and 2H electric field gradient (EFG) tensors of L-alanylglycine (L-alagly) dipeptide were calculated at RHF/6-31++G and B3LYP/6-31++G levels of theory respectively. For these calculations a crystal structure of this dipeptide obtained from X-ray crystallography was used. Atomic coordinates of different clusters containing several L-alagly molecules were used as input files for calculations. These clusters consist of central and surrounding L-alagly molecules, the latter forming short, strong, hydrogen bonds with the central molecule. Since the calculations did not converge for these clusters, the surrounding L-alagly molecules were replaced by glycine...