Mass‐Spectrometric Observation of Counter Anion Production in SU‐8 Exposed to UV Light and its Use for Dill C Parameter Determination

Photopolymerization is a phenomenon that is the basis of much of today's microfabrication technology and intense research is conducted to improve its control and the characteristics of end products for a variety of applications. The design of microscopic structures often relies on the accurate knowledge and modeling of photopolymer's behavior upon exposure, i.e. the Dill parameters, for each radiation species of interest and therefore the development of flexible characterization techniques is of great importance. SU‐8 is a popular compound that is representative of a whole class that relies on cationic polymerization, where an acid is obtained via photolysis of an onium salt during exposure. Here we report on the observation of SbF₆^? via laser desorption mass spectrometry on SU‐8 exposed to UV light at the wavelength of 365 nm and demonstrate that the yield of this counter‐anion as a function of exposure is consistent with the Dill C parameter value available in the literature. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019 , 57, 967–972     

Synthesis and characterization of cellulose acetate from cellophane industry residues. Application as acetaminophen controlled-release membranes

Journal of Thermal Analysis and Calorimetry - Cellophane film production generates cellulosic residues from scraps, edges, and low-quality films. In this work, cellophane was used as a raw material...     

QSAR modelling and structural aspects concerning synthetic heterocycles with larvicidal activity against Aedes aegypti

Structural Chemistry - In this paper, we present a quantitative structure–activity relationships modelling for two series of heterocyclic synthetic compounds with larvicidal activity against...     

On concentration of solution to a Schrödinger logarithmic equation with deepening potential well

In this work, we prove the existence of positive solution for the following class of problems where λ>0 and is a potential satisfying some conditions. Using the variational method developed by Szulkin for functionals, which are the sum of a C¹ functional with a convex lower semicontinuous functional, we prove that for each large enough λ>0, there exists a positive solution for the problem, and that, as λ→+∞, such solutions converge to a positive solution of the limit problem defined on the domain Ω=int(V^?1({0})).     

Thermal, rheological, and structural behaviors of natural and modified cassava starch granules, with sodium hypochlorite solutions

The use of chemically modified starches is widely accepted in various industries, with several applications. In this research, natural cassava starch granules were treated with standard sodium hypochlorite solution at 0.8, 2.0, and 5.0 g Cl/100 g starch. The native and modified starch samples were investigated by means of the following techniques: simultaneous thermogravimetry–differential thermal analysis, which allowed us to verify the thermal decomposition associated with endothermic or exothermic phenomena; and differential scanning calorimetry that was used to determine gelatinization enthalpy as well as the rapid viscoamylographic analysis that provided the pasting temperature and viscosity. By means of non-contact-atomic force microscopy method and X-ray powder patterns diffractometry, it was possible to observe the surface morphology, topography of starch granules, and alterations in the granules’ crystallinity.     

Chemometric Strategies to Develop a Nanocomposite Electrode for Simultaneous Determination of Ascorbic Acid,Dopamine, and Uric Acid

A simple and sensitive method for simultaneously measuring dopamine (DA), ascorbic acid (AA), and uric acid (UA) using a poly(1‐aminoanthracene) and carbon nanotubes nanocomposite electrode is presented. The experimental parameters for composite film synthesis as well as the variables related to simultaneous determination of DA, AA, and UA were optimized at the same time using fractional factorial and Doehlert designs. The use of carbon nanotubes and poly(1‐aminoanthracene) in association with a cathodic pretreatment led to three well‐defined oxidation peaks at potentials around ?0.039, 0.180 and 0.351 V (vs. Ag/AgCl) for AA, DA, and UA, respectively. Using differential pulse voltammetry, calibration curves for AA, DA, and UA were obtained over the range of 0.16–3.12×10^?3 mol L^?1, 3.54–136×10^?6 mol L^?1, and 0.76–2.92×10^?3 mol L^?1, with detection limits of 3.95×10^?5 mol L^?1, 2.90×10^?7 mol L^?1, and 4.22×10^?5 mol L^?1, respectively. The proposed method was successfully applied to determine DA, AA, and UA in biological samples with good results.     

Synthesis of New Five Membered Nitrogen Containing Heterocycles Bearing D-Galactose Side Chains

The synthesis of 5-[6′-deoxy-(1′,2′:3′,4′-di-O-isopropylidene-α-D-galactopyranos-6′-yl)]tetrazole and its reaction with acetic anhydride and 1,2:3,4-di-O-isopropylidene-6-O-(4-toluenesulfonyl)-α-D-galactopyranose are described.