Emulgel based on amphotericin B and bacuri butter (Platonia insignis Mart.) for the treatment of cutaneous leishmaniasis: characterization and in vitro assays

Objective: This work aimed to develop and characterize a topical emulgel of amphotericin B (AmB) with bacuri butter (Platonia insignis Mart.) and evaluate its antileishmanial activity using in vitro assays.

Significance: Leishmaniasis is considered an infectious disease, with high incidence and capacity to produce deformities. The first-line treatment recommended by WHO, with pentavalent antimonials, is aggressive and very toxic. Therefore, the development of topical treatments can emerge as a promising and less offensive alternative.

Methods: The developed formulations were evaluated for organoleptic characteristics, centrifugation resistance, globule size, pH, electrical conductivity, viscosity, spreadability, drug content, preliminary stability, in vitro release profile, evaluation of antileishmanial activity using promastigotes forms of Leishmania major as infecting agents, macrophage cytotoxicity and selectivity index (IS).

Results: Formulated emulsions presented organoleptic characteristics compatible with its constituents; pH values were suitable for topical application, ranging from 4.73 to 5.02; introduced non-Newtonian shear thinning system; drug content was within the established standards, and the most suitable kinetic model of release was the first order. Regarding the in vitro assays, formulations containing both 1% and 3% of AmB presented similar outcomes, indicating a synergism between the bacuri butter and the drug, possibly showing a reduction on cytotoxicity to host cells.

Conclusions: It was concluded that the formulations developed showed promising antileishmanial action and high potential for topical use.     

Retro‐Enantio N‐Methylated Peptides as β‐Amyloid Aggregation Inhibitors

An emerging and attractive target for the treatment of Alzheimer's disease is to inhibit the aggregation of β‐amyloid protein (Aβ). We applied the retro‐enantio concept to design an N‐methylated peptidic inhibitor of the Aβ42 aggregation process. This inhibitor, inrD, as well as the corresponding all‐L (inL) and all‐D (inD) analogues were assayed for inhibition of Aβ42 aggregation. They were also screened in neuroblastoma cell cultures to assess their capacity to inhibit Aβ42 cytotoxicity and evaluated for proteolytic stability. The results reveal that inrD and inD inhibit Aβ42 aggregation more effectively than inL, that inrD decreases Aβ42 cytotoxicity to a greater extent than inL and inD, and that as expected, both inD and inrD are stable to proteases. Based on these results, we propose that the retro‐enantio approach should be considered in future designs of peptide inhibitors of protein aggregation.     

Chemical orientation of lobsters,homarus americanus,in turbulent odor plumes

The lobster,Homarus americanus, relies upon its lateral antennules to make initial directional choices in a turbulent odor plume. To determine whether chemical signals provide cues for source direction and distance during orientation, we studied the search patterns of the lobster orienting within a turbulent odor plume. In an odor plume, animals walked significantly more slowly and most often up the middle of the tank; control animals (no odor present) walked rapidly in straight lines, frequently along a wall. Search patterns were not stereotyped either for the population of experimental animals or for individuals. Three different phases of orientation were evident: an initial stage during which the animals increased their walking speeds and decreased their heading angles; an intermediate stage where both the walking speed and headings were constant; and the final stage close to the source, where heading angles increased while walking speed decreased. During this last stage the animals appear to be switching from a distance orientation (mediated by the antennules) to a local food search (mediated by the walking legs) as evidenced by a great increase in leg-raking behavior.     

Tailored biodegradable films via extrusion blow molding using PBS,PBAT, and TPS

Research to replace synthetic polymers with biodegradable polymers is on the rise because common plastics have generated serious ecosystem problems. Films with thermoplastic starch (TPS), poly(butylene succinate) (PBS), poly(butylene adipate-co-butylene terephthalate (PBAT), and citric acid (CA) were produced by blown extrusion. They were characterized by blow-up ratio (BUR), water vapor permeability (WVP), soluble ratio (SR), water sorption isotherm, and thermogravimetric (TG) techniques. Films were uniform and showed BUR > 205%. The different proportions of PBS and PBAT significantly influenced the WVP of the films. All samples had WVP with an order of magnitude similar to other blends with high starch content (10⁻⁶ g m⁻¹ day⁻¹ Pa⁻¹). CA efficiently decreased the WVP of the PBS/PBAT/TPS formulations (15/15/70% and 20/10/70% by mass) by 25.2% and 24.7% compared to the acid-free formulations. There was no significant difference in SR (19.0%–20.1%). These materials were sensitive to moisture since the equilibrium moisture content increased pronouncedly from water activity of 0.5. Films showed good thermal stability, with a maximum decomposition temperature close to pure polyesters. CA did not increase the thermal stability of blends, probably because of the low content used (0.1%). Given the outcomes of this study, these films could be deemed appropriate for applications in food packaging.     

Cysteamine-CdTe Quantum Dots Electrochemically Synthesized as Fluorescence Probe for Resveratrol

This work proposes a fluorescent probe based on CdTe quantum dots (QDs) for the determination of resveratrol in wine samples. The synthesis of cysteamine (CA) capped CdTe QD was carried out in a one-pot eco-friendly process, resorting to the electrochemical reduction of metallic tellurium powder in a graphite macroelectrode (cavity cell). The reduced species of tellurium (Te^2? and Te₂^2?) migrated to an intermediate compartment of the electrochemical cell and in the presence of a cadmium salt and organic stabilizing agent (CA), forming the colloidal dispersion of CdTe in a single step. Under optimum synthesis conditions, the fluorescence intensity of the prepared nanoparticles varied linearly with the resveratrol concentration in the range from 3.25 to 75 μg L^?1 (R²?=?0.9984), with a detection limit of 0.97 μg L^?1 and RSD of 3.7% (5.0 μg L^?1 resveratrol, n?=?10). The method was successfully applied to the resveratrol determination in wines, with recoveries from 97.8 to 112.4%. Student’s t test was applied and no statistically significant difference was observed between the two methods (HPLC and proposed), with a confidence level of 95% (t_tabulated?=?2.45 and t_calculated?=?0.38). The resveratrol determination method, by using CdTe-CA QDs as fluorescence probe, was simple, rapid, inexpensive, and sensitive.     

Drawing Instruments

Despite the obvious diversity in the ideology, materiality and character of architectural production, here it is argued that the way we (architects) draw is surprisingly uniform. One reason for this might be the limited range of materials and tools we draw with, and their generic qualities. Architect, researcher and maker Nat Chard reveals relationships between acts of drawing, making images and making ideas, by taking us through the design and manufacture of a series of analytical drawing instruments and contingent works. Copyright © 2005 John Wiley & Sons, Ltd.     

Assessment of Brazilian consumers' perception about the presence of stabilisers in UHT milk: A study using virtual focus groups

Several countries use stabilisers in the product to avoid undesirable alterations, such as aggregation/gelation of proteins after thermal processing of UHT milk. Brazilian consumers' perception of these additives was investigated using virtual focus groups. Several relevant factors to the decision of consumers were elicited. The results show that most consumers do not have the habit of reading the UHT milk label and demonstrate a lack of knowledge about using stabilisers in UHT milk, even confusing it with preservatives. It is noted that the dairy sector must improve its communication strategies for UHT milk consumers.     

Complex pBAE Nanoparticle Cell Trafficking: Tracking Both Position and Composition Using Super Resolution Microscopy

Nanomedicine emerged some decades ago with the hope to be the solution for most unmet medical needs. However, tracking materials at nanoscale is challenging to their reduced size, below the resolution limit of most conventional techniques. In this context, we propose the use of direct stochastic optical reconstruction microscopy (dSTORM) to study time stability and cell trafficking after transfection of oligopeptide end-modified poly(β-aminoester) (OM-pBAE) nanoparticles. We selected different combinations of cationic end oligopeptides (arginine – R; histidine – H; and lysine – K) among polymer libraries, since the oligopeptide combination demonstrated to be useful for different applications, such as vaccination and gene silencing. We demonstrate that their time evolution as well as their cell uptake and trafficking are dependent on the oligopeptide. This study opens the pave to broad mechanistic studies at nanoscale that could enable a rational selection of specific pBAE nanoparticles composition after determining their stability and cell trafficking.