GDME-based methodology for the determination of free formaldehyde in cosmetics and hygiene products containing formaldehyde releasers

Analytical and Bioanalytical Chemistry - Formaldehyde is often applied in the industrial production of different products, such as textiles, insulation materials, or cosmetics, due to its...     

A memetic algorithm based on multiple learning procedures for global optimal design of composite structures

The mechanical properties of composite structures are sensitive to the choice of the material systems, the distribution of laminates on the structure, and the sizing at the laminate level. This sensitivity depends on many variables. To overcome the difficulties in attaining a global solution for the optimisation problem of composite structures, a new strategy is proposed based on the hybridisation of the memetic algorithm (MA) and the selfish gene (SG) algorithm. Instead of a local search, as performed in MAs, the selfish gene (SG) theory is applied, which follows a different learning scheme in which the conventional population of the individuals is replaced by a virtual population of alleles. The proposed approach, which is called the memetic-based selfish gene algorithm (MA + SG), is a mixed model that applies multiple learning procedures to explore the synergy of different cultural transmission rules in the evolutionary process. The principal aspects of the approach are as follows: co-evolution of multiple populations, species conservation, migration rules, self-adaptive multiple crossovers, local search in hybrid crossover with local genetic improvements, controlled mutation, individual age control, and feature-based allele statistical analysis. To discuss the capabilities of the proposed approach, numerical examples are represented to compare the results of MA + SG with those obtained using genetic algorithms (GA) and MA. The numerical results of the comparison tests showed that the GA and the MA maintained long periods without the evolution of the best-fitted individual/solutions. This behaviour during evolution is associated with the slow maturation of the elite group of populations in the GA and MA approaches. This behaviour is avoided when the MA + SG proposed approach is used with computational cost benefits.     

Host-guest Assembly Based on γ-Cyclodextrin-functionalized Multiwalled Carbon Nanotubes for Rutin Electrochemical Sensing

Here, we report multiwalled carbon nanotubes (MWCNTs) functionalized with γ-cyclodextrins (γCD) as a novel electrochemical strategy for Rutin determination, showing superior performance than β-cyclodextrins (βCD) modified MWCNTs, suggesting an adequate environment for host-guest interactions. Under optimized conditions, the sensor showed a linear range of 39–975 nmol L⁻¹ and a limit of detection of 7 nmol L⁻¹. When tested with quercetin, catechin, and caffeine, the platform presented high selectivity with an interference response <10 %. The method was employed to quantify Rutin in spiked pharmaceutical and herbal extracts, providing recovery of 93–98.4 %. Also, HPLC-PDA confirmed the method‘s accuracy.     

Characterization and adsorption capacity of Brazilian kaolin

Journal of Radioanalytical and Nuclear Chemistry - This study has evaluated chemical, radiological composition and determined the cation exchange capacity (CEC) for three commercially available...     

Efficiency analysis of thermosyphon solar flat plate collector with low mass concentrations of ND–Co3O4 hybrid nanofluids: an experimental study

Journal of Thermal Analysis and Calorimetry - In the present study, the thermal efficiency, convective heat transfer and friction factor analysis are investigated for a flat plate solar collector...     

Histopathological Analysis of UVB and IR Interaction in Rat Skin

To determine the chronic skin effects caused by the interaction of infrared and ultraviolet B radiations, male Rattus norvegicus (Wistar) (2 months old) were exposed for 15 days to infrared radiation (600–1500 nm, with a peak at 1000 nm, n = 12) for 30 min (1080 J cm^?2) (IRo); to ultraviolet B radiation (peak emission at 313 nm, n = 9) for 90 min (55.08 J cm^?2) (UVB); to infrared radiation followed after 90 min by ultraviolet B (n = 6) (IRUVB) and to ultraviolet B followed after 90 min by infrared radiation (n = 9) (UVBIR). Skin samples were collected and histopathological analysis showed the presence of acanthosis, parakeratotic and orthokeratotic hyperkeratosis, intraepidermal pustules, keratin pearls, detachment of epidermis, collagen necrosis, inflammatory infiltrate, vasodilation, basal cell vacuolization and superficial dermis degeneration both in UVB and UVBIR treatments. IRUVB animals showed the same characteristics as above except for parakeratotic hyperkeratosis, keratin pearls and superficial dermis degeneration. To conclude, infrared radiation exposure after ultraviolet B irradiation increases skin damage without protecting the tissue, while infrared radiation exposure before ultraviolet B irradiation showed a protective effect against ultraviolet skin damage.     

Molecular characterization and first report of Cryptosporidium genotypes in human population in the Slovak Republic

In our study, we examined 91 fecal samples from five different groups of people containing HIV patients, hemodialysis patients, kidney transplant recipients, immunocompetent humans without clinical signs, and humans with suspected cryptosporidiosis. The purpose of our study was to determine species and genotype composition of representatives of Cryptosporidium spp. using PCR analysis of small subunit ribosomal RNA gene and 60‐kDa glycoprotein gene and examine their phylogenetic relationship. In HIV‐positive/AIDS‐infected group of patients and in hemodialysis patients, no presence of Cryptosporidium species was detected. In two kidney transplant recipients, we detected species/genotypes Cryptosporidium parvum IIaA13G1T1R1 (KT355488) and Cryptosporidium hominis IaA11G2R8 (KT355489) and in two immunocompetent patients with clinical symptoms, we identified Cryptosporidium muris and C. hominis IbA10G2T1 (KT355490). In the group of healthy immunocompetent individuals without clinical signs, we identified species/genotype C. hominis IbA11G2 (KT355491) in one sample.