Thionicotinamide SAM on Gold: Adsorption Studies and Electroactivity

STM and impedance results of the self‐assembled monolayer (SAM) formed with thionicotinamide (TNA) on gold indicate the presence of defects that increase with the immersion time of the electrode in the TNA solution affecting the SAM electroactivity toward the electron transfer reaction of the cytochrome c metalloprotein and [Fe(CN)₆]^4? and [Ru(NH₃)₆]³⁺ complexes. It was observed that this electroactivity was also affected by the pH of the electrolyte solution. SERS and STM data indicate sulfur coordination to the surface with contribution of the NH₂ group. From the dependence of the TNA surface coverage on the temperature and concentration in solution, thermodynamic parameters of adsorption were determined.     

Crystal structure and theoretical calculations of Julocrotine,a natural product with antileishmanial activity

Julocrotine, N‐(2,6‐dioxo‐1‐phenethyl‐piperidin‐3‐yl)‐2‐methyl‐butyramide, is a potent antiproliferative agent against the promastigote and amastigote forms of Leishmania amazonensis (L.). In this work, the crystal structure of Julocrotine was solved by X‐ray diffraction, and its geometrical parameters were compared with theoretical calculations at the B3LYP and HF level of theory. IR and NMR spectra also have been obtained and compared with theoretical calculations. IR absorptions calculated with the B3LYP level of theory employed together with the 6‐311G+(d,p) basis set, are close to those observed experimentally. Theoretical NMR calculations show little deviation from experimental results. The results show that the theory is in accordance with the experimental data. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2008     

An entropy-based approach to automatic image segmentation of satellite images

An entropy-based image segmentation approach is introduced and applied to color images obtained from Google Earth. Segmentation refers to the process of partitioning a digital image in order to locate different objects and regions of interest. The application to satellite images paves the way to automated monitoring of ecological catastrophes, urban growth, agricultural activity, maritime pollution, climate changing and general surveillance. Regions representing aquatic, rural and urban areas are identified and the accuracy of the proposed segmentation methodology is evaluated. The comparison with gray level images revealed that the color information is fundamental to obtain an accurate segmentation.     

Application of chitosan matrix for delivery of rutin

Chitosan matrices are an alternative material to the food industry, due to its ability to release bioactive compounds through interconnected cavities. Chitosan is a biomaterial of excellence, because it shows unique features, such as biocompatibility, non-toxicity, bactericidal action and the ability to associate with other compounds. Thus, this study aimed the development of chitosan matrices incorporated with rutin, as well as the evaluation of rutin release. Chitosan matrices with rutin were prepared by the coacervation method in alkaline solution and subsequently characterized through FT-IR, TG-DSC, X-ray diffraction, SEM and further submitted to rutin release assay. Results show the effectiveness in the incorporation of rutin into the polymeric matrix. The polymeric matrix with rutin can quickly release it, which provides a wide range of applications, such as carrier of rutin as a micronutrient food additive.     

Leaf volatiles and secretory cells of Alpinia zerumbet (Pers.) Burtt et Smith (Zingiberaceae)

Plant leaves are commonly used in folk medicine and food industry. Their volatile composition is an important determinant in such applications. However, to properly assess the quality of volatiles, proper analytic tools must be utilised. Accordingly, the static headspace technique was used to evaluate the main volatiles emitted from in vitro-grown Alpinia zerumbet plants cultured with indole-3-acetic acid, thidiazuron, benzyladenine or kinetin, under standard physical conditions, as compared to those of field-grown donor plants. Although the leaf aroma of the donor plants was found to be a complex mixture, mainly consisting of sabinene, α and γ-terpinene, 1,8-cineole and caryophyllene, volatile analyses from most of the in vitro samples only revealed the presence of sabinene and caryophyllene. Many alkanes were found in the aromas after treating plantlets with cytokinins. Histochemical analysis of leaf sections was also carried out. Secretory cells found in the epidermis and mesophyll showed a strong positive reaction to lipophilic compounds using Oil red and Nile blue reagents. These findings demonstrated how in vitro conditions may alter the quality of volatiles in micropropagation systems, while leaf anatomy analysis revealed a large quantity of oil cells in the mesophyll as a constant feature responsible for the production of volatile compounds in both donor and in vitro-grown plants.     

Casbane diterpene as a promising natural antimicrobial agent against biofilm-associated infections

Croton nepetaefolius is a native plant from northeastern Brazil that belongs to the Euphorbiaceae family. The biological action of this plant has been extensively explored, being the secondary metabolites responsible for its properties alkaloids, diterpenes, and triterpenes. This study aimed to evaluate the ability of casbane diterpene (CD), isolated from the ethanolic extract of C. nepetaefolius, to inhibit microbial growth and biofilm formation of several clinical relevant species (bacteria and yeasts). It was found that CD possessed biocidal and biostatic activity against the majority of the species screened, with minimal active concentrations ranging between 125 and 500 μg/mL. In addition, it was observed that biofilm formation was inhibited even when the planktonic growth was not significantly affected. In conclusion, CD showed potential to be a natural tool for the treatment of diseases caused by different infectious microorganisms.     

Long-term integrated surgery room optimization and recovery ward planning,with a case study in the Brazilian National Institute of Traumatology and Orthopedics (INTO)

This paper proposes an integrated approach for the long-term planning and surgery allocation problem with downstream constraints. It is motivated by a case study in the Brazilian National Institute of Traumatology and Orthopedics, which provides elective high complexity surgeries for patients from the Brazilian public health system. We introduce an optimization problem that designs a periodic surgery allocation schedule as well as a recovery ward utilization plan, with a view at balancing patient arrivals and releases in the long term, in such a way that all surgeries are performed in a timely manner.     

Accelerating the convergence of value iteration by using partial transition functions

This work proposes an algorithm that makes use of partial information to improve the convergence properties of the value iteration algorithm in terms of the overall computational complexity. The algorithm iterates on a series of increasingly refined approximate models that converges to the true model according to an optimal linear rate, which coincides with the convergence rate of the original value iteration algorithm. The paper investigates the properties of the proposed algorithm and features a series of switchover queue examples which illustrates the efficacy of the method.