Improved Selective Cholesterol Adsorption By Molecularly Imprinted Poly(methacrylic Acid)/silica (pmaa-sio₂) Hybrid Material Synthesized With Different Molar Ratios.

The present paper describes the synthesis of molecularly imprinted polymer - poly(methacrylic acid)/silica and reports its performance feasibility with desired adsorption capacity and selectivity for cholesterol extraction. Two imprinted hybrid materials were synthesized at different methacrylic acid (MAA)/tetraethoxysilane (TEOS) molar ratios (6:1 and 1:5) and characterized by FT-IR, TGA, SEM and textural data. Cholesterol adsorption on hybrid materials took place preferably in apolar solvent medium, especially in chloroform. From the kinetic data, the equilibrium time was reached quickly, being 12 and 20 min for the polymers synthesized at MAA/TEOS molar ratio of 6:1 and 1:5, respectively. The pseudo-second-order model provided the best fit for cholesterol adsorption on polymers, confirming the chemical nature of the adsorption process, while the dual-site Langmuir-Freundlich equation presented the best fit to the experimental data, suggesting the existence of two kinds of adsorption sites on both polymers. The maximum adsorption capacities obtained for the polymers synthesized at MAA/TEOS molar ratios of 6:1 and 1:5 were found to be 214.8 and 166.4 mg g(-1), respectively. The results from isotherm data also indicated higher adsorption capacity for both imprinted polymers regarding to corresponding non-imprinted polymers. Nevertheless, taking into account the retention parameters and selectivity of cholesterol in the presence of structurally analogue compounds (5-α-cholestane and 7-dehydrocholesterol), it was observed that the polymer synthesized at the MAA/TEOS molar ratio of 6:1 was much more selective for cholesterol than the one prepared at the ratio of 1:5, thus suggesting that selective binding sites ascribed to the carboxyl group from MAA play a central role in the imprinting effect created on MIP.

Removal Of Glyphosate Herbicide From Water Using Biopolymer Membranes.

Enormous amounts of pesticides are manufactured and used worldwide, some of which reach soils and aquatic systems. Glyphosate is a non-selective herbicide that is effective against all types of weeds and has been used for many years. It can therefore be found as a contaminant in water, and procedures are required for its removal. This work investigates the use of biopolymeric membranes prepared with chitosan (CS), alginate (AG), and a chitosan/alginate combination (CS/AG) for the adsorption of glyphosate present in water samples. The adsorption of glyphosate by the different membranes was investigated using the pseudo-first order and pseudo-second order kinetic models, as well as the Langmuir and Freundlich isotherm models. The membranes were characterized regarding membrane solubility, swelling, mechanical, chemical and morphological properties. The results of kinetics experiments showed that adsorption equilibrium was reached within 4 h and that the CS membrane presented the best adsorption (10.88 mg of glyphosate/g of membrane), followed by the CS/AG bilayer (8.70 mg of glyphosate/g of membrane). The AG membrane did not show any adsorption capacity for this herbicide. The pseudo-second order model provided good fits to the glyphosate adsorption data on CS and CS/AG membranes, with high correlation coefficient values. Glyphosate adsorption by the membranes could be fitted by the Freundlich isotherm model. There was a high affinity between glyphosate and the CS membrane and moderate affinity in the case of the CS/AG membrane. Physico-chemical characterization of the membranes showed low values of solubility in water, indicating that the membranes are stable and not soluble in water. The SEM and AFM analysis showed evidence of the presence of glyphosate on CS membranes and on chitosan face on CS/AG membranes. The results showed that the glyphosate herbicide can be adsorbed by chitosan membranes and the proposed membrane-based methodology was successfully used to treat a water sample contaminated with glyphosate. Biopolymer membranes therefore potentially offer a versatile method to eliminate agricultural chemicals from water supplies.

The Conformational Analysis Of 2-halocyclooctanones.

The establishment of the most stable structures of eight membered rings is a challenging task to the field of conformational analysis. In this work, a series of 2-halocyclooctanones were synthesized (including fluorine, chlorine, bromine and iodine derivatives) and submitted to conformational studies using a combination of theoretical calculation and infrared spectroscopy. For each compound, four conformations were identified as the most important ones. These conformations are derived from the chair-boat conformation of cyclooctanone. The pseudo-equatorial (with respect to the halogen) conformer is preferred in vacuum and in low polarity solvents for chlorine, bromine and iodine derivatives. For 2-fluorocyclooctanone, the preferred conformation in vacuum is pseudo-axial. In acetonitrile, the pseudo-axial conformer becomes the most stable for the chlorine derivative. According to NBO calculations, the conformational preference is not dictated by electron delocalization, but by classical electrostatic repulsions.

Avaliação dos tipos de glaucoma no serviço de oftalmologia da UNICAMP

PURPOSE: To evaluate the frequency of different types of glaucoma at the Hospital das Clínicas of Campinas State University. METHODS: Cross-sectional study of 329 patients followed at the Glaucoma Service of Campinas State University from October 1 to December 20, 2000. The frequency of each type of glaucoma and the treatment were analyzed. RESULTS: There were 329 patients examined at the Glaucoma Service: 132 (40.1%) were referred to the service as glaucoma suspects and 197 (59.9%) as glaucoma patients. Ninety of the 132 glaucoma suspects had glaucoma (68.2%) and 42 are still under investigation (31.8%). Among the 329 patients, 283 (86%) had glaucoma, 42 (12.8%) were glaucoma suspects, 2 (0.6%) had ocular hypertension and 2 (0.6%) did not have glaucoma. There were 530 eyes with glaucoma: 298 (56.2%) with primary open angle glaucoma, 108 (20.4%) with chronic angle closure glaucoma, 21 (4%) with glaucoma following cataract surgery, 19 (3.6%) congenital glaucoma and 16 (3%) with low-tension glaucoma. All patients received initial clinical treatment with IOP-lowering medication. After a mean follow up of 10.5 months, 89 (16.8%) underwent laser therapy: 72 (13.6%) iridotomy, 7 (1.3%) trabeculoplasty and 10 (1.9%) panphotocoagulation. A hundred and seventy nine (33%) eyes required surgical treatment. CONCLUSION: The most frequent types of glaucoma were primary open angle and angle closure glaucoma. Low tension glaucoma and glaucoma associated with exfoliation syndrome were uncommon in this population.

Calcificações dos gânglios da base na infância

We report the study of four children with bilateral basal ganglia calcifications (BGC) visualized on CT scan. Epilepsy was the clinical manifestation of three patients whose laboratory investigation revealed abnormal calcium metabolism. The first aim of this paper is to call attention to a treatable entity that can cause epileptic syndromes in infancy and childhood. The second purpose is to review the literature comparing with our fourth child who presented encephalopathy with BGC.

Imagens de beleza : o dilema de Paris

Universidade Estadual de Campinas. Faculdade de Educação Física