4,9-Diaminoacridines and 4-Aminoacridines as Dual-Stage Antiplasmodial Hits

Multi-stage drugs have been prioritized in antimalarial drug discovery, as targeting more than one process in the Plasmodium life cycle is likely to increase efficiency, while decreasing the chances of emergence of resistance by the parasite. Herein, we disclose two novel acridine-based families of compounds that combine the structural features of primaquine and chloroquine. Compounds prepared and studied thus far retained the in vitro activity displayed by the parent drugs against the erythrocytic stages of chloroquine-sensitive and -resistant Plasmodium falciparum strains, and against the hepatic stages of Plasmodium berghei, hence acting as dual-stage antiplasmodial hits.     

Influence of photodegradation with UV radiation in biotreatment with Paecilomyces variotti on PHBV /GNS nanocomposites

Graphite nanosheets (GNSs) and poly(hydroxybutyrate‐co ‐hydroxyvalerate) (PHBV) nanocomposites were prepared by solution casting method. This study aimed to evaluate the effects of previously phototreatment with ultraviolet (UV) radiation on the biotreatment with Paecilomyces variotti of neat PHBV and PHBV /GNS nanocomposites. Some samples of PHBV film were submitted only to biotreatment with P. variotti during 120 days; other samples were subjected to phototreatment (UV radiation) for 30 h followed by biodegradation assessment with P. variotti for a period of 120 days. The effects of biotreatments on thermal properties were studied through differential scanning calorimetry. The PHBV films were monitored by weight changes as a function of time. Also, their surfaces were examined after the tests using scanning electron microscopy, contact angle and roughness measurements. The level of oxidation was recorded by means of carbonyl index evaluation by Fourier transformed infrared spectroscopy spectroscopy. The phototreatment of PHBV films influenced the process of adhesion and colonisation by P. variotti on the surface of the films, and enhanced morphological and structural changes.Inspec keywords: ultraviolet radiation effects, nanocomposites, graphite, polymer blends, casting, nanofabrication, biodegradable materials, scanning electron microscopy, differential scanning calorimetry, contact angle, surface roughness, oxidation, Fourier transform infrared spectra, adhesionOther keywords: photodegradation, biotreatment, Paecilomyces variotti, nanocomposites, graphite nanosheets, poly(hydroxybutyrate‐co‐hydroxyvalerate), solution casting, ultraviolet radiation, biodegradation assessment, thermal properties, differential scanning calorimetry, scanning electron microscopy, contact angle, roughness measurements, oxidation, carbonyl index evaluation, Fourier transformed infrared spectroscopy, adhesion, colonisation, morphological change, structural change, time 120 d, time 30 h, C     

Sensor film based on electrical resistance of graphene nanoplatelets and polystyrene (XGNP/PS): fabrication,characterization, and application

Journal of Materials Science: Materials in Electronics - The objective of this work was to develop a sensor based on variation of the electrical resistance of graphene-polystyrene sensor film...     

Jaboticaba (Plinia peruviana) extract nanoemulsions: development,stability, and in vitro antioxidant activity

Objective: The aim of this work is to develop and characterize nanoemulsions containing jaboticaba extract (Plinia peruviana) aiming pharmaceutical and cosmetic applications.

Methods: Nanoemulsions were prepared by high-pressure homogenization method using different concentrations of components (oil, surfactant, and extract) and homogenization pressures, in order to optimize the preparation conditions. Both unloaded and extract-loaded nanoemulsions were characterized according to their size, polydispersity, zeta potential, pH, morphology, and physical stability. Total phenolic and flavonoid contents in free jaboticaba extract and jaboticaba-loaded nanoemulsions were determined spectrophotometrically, while ellagic acid content was determined by high-performance liquid chromatography (HPLC) analysis. In vitro antioxidant activity was investigated by 2, 2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) methods.

Results: Colloidal dispersions exhibited a mean particle size around 200?nm, with monodisperse size distribution (PdI <0.3), and spherical shape. Stability studies showed that nanoemulsions were stable over 120?d of storage at room temperature. Jaboticaba nanoemulsions showed significant concentrations of phenolics, flavonoids, and ellagic acid, with encapsulation efficiency values higher than 90%. Antioxidant properties of jaboticaba nanoemulsions were demonstrated by its remarkable ability to scavenge DPPH free radicals and to reduce ferric–tripyridyltriazine complex, which can be attributed to their phenolic and flavonoid contents.

Conclusions: The results suggest that nanoemulsions containing jaboticaba extract can be considered a promising candidate as a new antioxidant agent.     

Electrospun poly(ε-caprolactone) matrices containing silver sulfadiazine complexed with β-cyclodextrin as a new pharmaceutical dosage form to wound healing: preliminary physicochemical and biological evaluation

Cooperation between researchers in the areas of medical, pharmaceutical and materials science has facilitated the development of pharmaceutical dosage forms that elicit therapeutic effects and protective action with a single product. In addition to optimizing pharmacologic action, such dosage forms provide greater patient comfort and increase success and treatment compliance. In the present work, we prepared semipermeable bioactive electrospun fibers for use as wound dressings containing silver sulfadiazine complexed with β-cyclodextrin in a poly(?-caprolactone) nanofiber matrix aiming to reduce the direct contact between silver and skin and to modulate the drug release. Wound dressings were prepared by electrospinning, and were subjected to ATR-FT-IR and TG/DTG assays to evaluate drug stability. The hydrophilicity of the fibrous nanostructure in water and PBS buffer was studied by goniometry. Electrospun fibers permeability and swelling capacity were assessed, and a dissolution test was performed. In vitro biological tests were realized to investigate the biological compatibility and antimicrobial activity. We obtained flexible matrices that were each approximately 1.0?g in weight. The electrospun fibers were shown to be semipermeable, with water vapor transmission and swelling indexes compatible with the proposed objective. The hydrophilicity was moderate. Matrices containing pure drug modulated drug release adequately during 24?h but presented a high hemolytic index. Complexation promoted a decrease in the hemolytic index and in the drug release but did not negatively impact antimicrobial activity. The drug was released predominantly by diffusion. These results indicate that electrospun PCL matrices containing β-cyclodextrin/silver sulfadiazine inclusion complexes are a promising pharmaceutical dosage form for wound healing.     

Untangling Cooperative Effects of Pyridinic and Graphitic Nitrogen Sites at Metal‐Free N‐Doped Carbon Electrocatalysts for the Oxygen Reduction Reaction

Metal‐free carbon electrodes with well‐defined composition and smooth topography are prepared via sputter deposition followed by thermal treatment with inert and reactive gases. X‐ray photoelectron spectroscopy (XPS) and Raman spectroscopy show that three carbons of similar N/C content that differ in N‐site composition are thus prepared: an electrode consisting of almost exclusively graphitic‐N (N_G), an electrode with predominantly pyridinic‐N (N_P), and one with ≈1:1 N_G:N_P composition. These materials are used as model systems to investigate the activity of N‐doped carbons in the oxygen reduction reaction (ORR) using voltammetry. Results show that selectivity toward 4e‐reduction of O₂ is strongly influenced by the N_G/N_P site composition, with the material possessing nearly uniform N_G/N_P composition being the only one yielding a 4e‐reduction. Computational studies on model graphene clusters are carried out to elucidate the effect of N‐site homogeneity on the reaction pathway. Calculations show that for pure N_G‐doping or N_P‐doping of model graphene clusters, adsorption of hydroperoxide and hydroperoxyl radical intermediates, respectively, is weak, thus favoring desorption prior to complete 4e‐reduction to hydroxide. Clusters with mixed N_G/N_P sites display synergistic effects, suggesting that co‐presence of these sites improves activity and selectivity by achieving high theoretical reduction potentials while facilitating retention of intermediates.     

Electromechanical measurements of electric field-induced displacements of fibers

In this paper we report on a development of a new method for measurements of electric field-induced displacements in a cylindrical geometry (optical fiber with the deposited piezoelectric film). The measurement setup is based on a commercially available Fotonic Sensor MTI 2000 (MTI Inc.). Major disadvantages of measurement by standard techniques (e.g., interferometry) such as low reflectivity, high roughness of the coating resulting in poor fringe quality, and big displacement range are successfully avoided using a special configuration of an optical probe and a sample. The method allows performing investigations of electromechanically induced vibrations in a broad frequency range (from 0 up to 150 kHz) and various combinations of ac and dc voltages. The capabilities of the proposed method are validated by strain measurements of an optical fiber cantilever beam covered by Pb(Zr,Ti)O(3) thick film.     

Towards automated requirements prioritization and triage

Time-to-market deadlines and budgetary restrictions require stakeholders to carefully prioritize requirements and determine which ones to implement in a given product release. Unfortunately, existing prioritization techniques do not provide sufficient automation for large projects with hundreds of stakeholders and thousands of potentially conflicting requests and requirements. This paper therefore describes a new approach for automating a significant part of the prioritization process. The proposed method utilizes data-mining and machine learning techniques to prioritize requirements according to stakeholders’ interests, business goals, and cross-cutting concerns such as security or performance requirements. The effectiveness of the approach is illustrated and evaluated through two case studies based on the requirements of the Ice Breaker System, and also on a set of stakeholders’ raw feature requests mined from the discussion forum of an open source product named SugarCRM.     

Electron microscopy and morphometric analyses of microtubules in two differently sized types of axons in the protocerebral tract of a crustacean

Despite several reports on the morphology and functions associated with the morphometry of the vertebrate axoplasm cytoskeleton, the subject has not been thoroughly explored in invertebrates. In vertebrates, among many other functions, microtubules (MTs) serve as scaffolding for axon assembly, and neurofilaments (NFs) as the elements that determine the axon caliber. Intermediate filaments have never been described by electron microscopy in arthropods, although NF proteins have been revealed in the MT side-arms of the axoplasm of certain species, such as the crab Ucides cordatus. Thus, it is not known which elements of the cytoskeleton of invertebrates are responsible for determination of the axon caliber. We studied, by electron microscopy and morphometric analyses, the MT and axon area variability in differently sized axons of the protocerebral tract of the crab Ucides cordatus. Our results revealed differences in the distance between MTs, in MT density and number, and in the areas of differently sized axons. The number of MTs increases with the axon area, but this relationship is not directly proportional. Therefore, MT density is greater in smaller axons than in medium axons, similar to the morphometry of the vertebrate axon MT. The distance between MTs is, however, directly related to the axonal area. On the basis of the results shown here, and on previous reports by us and others, we suggest that MTs may be involved in the determination of the axon caliber, possibly due to the presence of NF proteins found in the side-arms.     

Don’t do this – Pitfalls in using anti-patterns in teaching human–computer interaction principles

This paper explores the use of design patterns and anti-patterns in teaching human–computer interaction principles. Patterns are increasingly popular and are seen as an efficient knowledge transfer mechanism in many fields, including software development in the field of software engineering, and more recently in the field of human–computer interaction. In software engineering a concerted effort is also being made to identify and document anti-patterns for recording the experiences of expert software developers to caution novices against potential bad practices. It is, however, essential that we ensure compatibility with the learner’s internal knowledge representation and acquisition processes, whether we are attempting to convey the knowledge in the form of a pattern or an anti-pattern. Since teaching with anti-patterns implies using negation, the primary aim of the research reported in this paper is to explore the efficacy of negative, rather than positive, teaching mechanisms. Evidence from theories of mental modelling and knowledge acquisition that highlight significant dangers in the use of anti-patterns to teach novices human–computer interaction principles is presented and supported with empirical findings. We started off by investigating the use of patterns (positive) in teaching, and then carried out experiments to test the use of anti-patterns (negative) in teaching HCI principles. This paper, whilst reporting mainly on our findings with respect to HCI design anti-patterns, will also identify some problems with the structure and use of patterns and anti-patterns in pedagogy.