Coumarin Derivatives in Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a non-communicable disease characterized by a chronic inflammatory process of the gut and categorized into Crohn’s disease and ulcerative colitis, both currently without definitive pharmacological treatment and cure. The unclear etiology of IBD is a limiting factor for the development of new drugs and explains the high frequency of refractory patients to current drugs, which are also related to various adverse effects, mainly after long-term use. Dissatisfaction with current therapies has promoted an increased interest in new pharmacological approaches using natural products. Coumarins comprise a large class of natural phenolic compounds found in fungi, bacteria, and plants. Coumarin and its derivatives have been reported as antioxidant and anti-inflammatory compounds, potentially useful as complementary therapy of the IBD. These compounds produce protective effects in intestinal inflammation through different mechanisms and signaling pathways, mainly modulating immune and inflammatory responses, and protecting against oxidative stress, a central factor for IBD development. In this review, we described the main coumarin derivatives reported as intestinal anti-inflammatory products and its available pharmacodynamic data that support the protective effects of these products in the acute and subchronic phase of intestinal inflammation.     

Artificial Neural Networks for Pyrolysis,Thermal Analysis,and Thermokinetic Studies: The Status Quo

Artificial neural networks (ANNs) are a method of machine learning (ML) that is now widely used in physics, chemistry, and material science. ANN can learn from data to identify nonlinear trends and give accurate predictions. ML methods, and ANNs in particular, have already demonstrated their worth in solving various chemical engineering problems, but applications in pyrolysis, thermal analysis, and, especially, thermokinetic studies are still in an initiatory stage. The present article gives a critical overview and summary of the available literature on applying ANNs in the field of pyrolysis, thermal analysis, and thermokinetic studies. More than 100 papers from these research areas are surveyed. Some approaches from the broad field of chemical engineering are discussed as the venues for possible transfer to the field of pyrolysis and thermal analysis studies in general. It is stressed that the current thermokinetic applications of ANNs are yet to evolve significantly to reach the capabilities of the existing isoconversional and model-fitting methods.     

Simultaneous determination of thirteen plant alkaloids in a human specimen by SPE and HPLC

A new screening method for the simultaneous determination of thirteen plant alkaloids (aconitine, anabasine, atropine, brucine, colchicine, cotinine, cytisine, harmine, ibogaine, nicotine, scopolamine, strychnine, yohimbine) in a human specimen was developed based on solid-phase extraction and reversed-phase liquid chromatography with photodiode array detection. The validated method enables selective identification as well as accurate and sensitive quantification. The analysis of forensic and clinical samples emphasizes the applicability for intoxications and drug abuse, as well as for compliance control.     

NIR-FT-Raman spectroscopic analytical characterization of the fruits, seeds, and phytotherapeutic oils from rosehips

In this study nondestructive Raman spectroscopic analysis of rosehips has been conducted by laser excitation at 1064 nm, with the objective of direct measurement of different parts of the fruit, including the inside and outside of the seeds, while preserving the integrity of the more representative chemicals. Carotenoid substances are responsible for the major Raman features in the spectra of the fruit parts; analysis of the nu(1) mode (1520 cm(-1)) strongly indicates the presence of a C(9) carotene, and analysis of the main characteristic carotene band set (C=C, C-C, and C-CH(3) stretching modes at 1520, 1157, and 1007 cm(-1), respectively) suggests the presence of beta-carotene as the main constituent. Raman spectra of the seed parts show the presence of unsaturated fatty acids, which are predominant inside the seed; these spectra also reveal the fatty products content comprises cis isomers. Analysis of the CH-stretching region bands and comparison with those in the spectra obtained from linoleic acid and commercial rosehip oil indicate that the relative band intensity of the CH-stretching mode is strongly affected by the chemical environment of the fatty acid esters present in both parts (inside and outside) of rosehips seeds.     

Threshold θ ≥ 2 contact processes on homogeneous trees

We study the threshold θ ≥ 2 contact process on a homogeneous tree of degree κ = b + 1, with infection parameter λ ≥ 0 and started from a product measure with density p. The corresponding mean-field model displays a discontinuous transition at a critical point and for it survives iff , where this critical density satisfies , . For large b, we show that the process on has a qualitatively similar behavior when λ is small, including the behavior at and close to the critical point . In contrast, for large λ the behavior of the process on is qualitatively distinct from that of the mean-field model in that the critical density has . We also show that , where 1 < Φ₂ < Φ₃ < ..., , and . The work of L.R.F. was partially supported by the Brazilian CNPq through grants 307978/2004-4 and 475833/2003-1, and by FAPESP through grant 04/07276-2. The work of R.H.S. was partially supported by the American N.S.F. through grant DMS-0300672.     

Rapid and direct determination of glyphosate and aminomethylphosphonic acid in water using anion-exchange chromatography with coulometric detection

A simple, rapid, and low-cost coulometric method for direct detection of glyphosate and aminomethylphosphonic acid (AMPA) in water samples using anion-exchange chromatography and coulometric detection with copper electrode is presented. Under optimized conditions, the limits of detection (LODs) (S/N=3) were 0.038microgml(-1) for glyphosate and 0.24microgml(-1) for AMPA, without any preconcentration method. The calibration curves were linear and presented an excellent correlation coefficient. The method was successfully applied to the determination of glyphosate and AMPA in water samples without any kind of extraction, clean-up, or preconcentration step. No interferent was found in the water, like this, the recovery was, practically, 100%.     

Fully relativistic calculations on the potential energy surfaces of the lowest 23 states of molecular chlorine

The electronic structure and spectroscopic properties (R(e), omega(e), omega(e)x(e), beta(e), and T(e)) of the ground state and the 22 lowest excited states of chlorine molecule were studied within a four-component relativistic framework using the MOLFDIR program package. The potential energy curves of all possible 23 covalent states were calculated using relativistic complete open shell configuration interaction approach. In addition, four component multireference configuration interaction with single and double excitation calculations were performed in order to infer the effects due to dynamical correlation in vertical excitations. The calculated properties are in good agreement with the available experimental data.     

Development and validation of a method for quantitative determination of econazole nitrate in cream formulation by capillary zone electrophoresis

A simple, fast, inexpensive and reliable capillary zone electrophoresis (CZE) method for the determination of econazole nitrate in cream formulations has been developed and validated. Optimum conditions comprised a pH 2.5 phosphate buffer at 20 mmol L(-1) concentration, +30 kV applied voltage in a 31.5 cm x 50 microm I.D. capillary. Direct UV detection at 200 nm led to an adequate sensitivity without interference from sample excipients. A single extraction step of the cream sample in hydrochloric acid was performed prior to injection. Imidazole (100 microg mL(-1)) was used as internal standard. Econazole nitrate migrates in approximately 1.2 min. The analytical curve presented a coefficient of correlation of 0.9995. Detection and quantitation limits were 1.85 and 5.62 microg mL(-1), respectively. Excellent accuracy and precision were obtained. Recoveries varied from 98.1 to 102.5% and intra- and inter-day precisions, calculated as relative standard deviation (RSD), were better than 2.0%. The proposed CZE method presented advantageous performance characteristics and it can be considered suitable for the quality control of econazole nitrate cream formulations.     

Development, optimization and validation of gas chromatographic fingerprinting of Brazilian commercial gasoline for quality control

Three-step development, optimization and validation strategy for GC fingerprints of Brazilian commercial gasoline is described. A suitable chromatographic system was selected first. The following step was to improve acceptable chromatographic resolution with reduced analysis time, which is recommended for routine applications. Optimization was carried out using full three-level factorial designs. Optimal conditions were obtained for flow rate, oven ramps, injection volume and split ratio. Finally, several validation parameters were performed. Therefore, a feasible and reliable fingerprint was established to identify Brazilian commercial gasoline quality. This strategy can also be applied to develop fingerprints for quality control of other fuels.     

1,5-Asymmetric induction in boron-mediated aldol reactions of beta-alkoxy methylketones

Good levels of substrate-controlled, 1,5- syn-stereoinduction are obtained in boron-mediated aldol reactions of beta-trichloromethyl-beta-alkoxy and beta-trifluoromethyl-beta-alkoxy methylketones with achiral aldehydes, independent of the nature of the beta-alkoxy protecting group (TBS or PMB). In the case of boron aldol reactions of beta-aryl-beta-alkoxy methylketones, the 1,5- anti-adducts were obtained with high levels of diastereoselectivity only with a beta-OPMB group.