Universidad Técnica Particular de Loja (UTPL) is a private institution that provides on-campus and continuing education programmes. There are 23 Bachelor's degrees on the Loja campus and 20 continuing education programmes.It is considered the best distance-modality university of Ecuador and has abroad campuses in Rome, Madrid and New York.
The supercritical-CO₂ anti-solvent (SAS) process was employed to co-precipitate ethanolic extract of red habanero chili pepper (HEE) with polyvinylpyrrolidone (PVP), aiming to produce microparticles. HEE was obtained using ethanol as a solvent through ultrasound-assisted extraction. A Box–Behnken design evaluated the effects of pressure (80–160 bar), temperature (35–55 °C) and HEE solids/PVP mass ratio (1/1–1/3) on particle morphology, yield and capsaicinoids retention. Resulting microparticles exhibited median diameters range (d50) from ∼2 µm to 390 µm, and their total capsaicinoids content varied between 3.7 and 106.8 mg/g. Pressure was identified as the most significant variable influencing yield and particle formation, while PVP ratio strongly affected capsaicinoids retention and size distribution. At 120 bar, 45 °C, 1/2 HEE solids/PVP the SAS method process produced spherical or near-spherical particles with uniform morphology and significant capsaicinoids load (101 mg TC/g), 17
PurposeThis research work aims to arise from developing new communication channels for customer service in micro, small and medium enterprises (MSMEs), such as chatbots. In particular, the results of the usability testing of three chatbots implemented in MSMEs are presented.Design/methodology/approachThe methodology employed includes participants, chatbot development platform, research methodology, software development methodology and usability test to contextualize the study's results.FindingsBased on the results obtained from the System Usability Scale (SUS) and considering the accuracy of the chatbot's responses, it is concluded that the level of satisfaction in using chatbots is high; therefore, if the chatbot is well integrated with the communication systems/channels of the MSMEs, the client receives an excellent, fast and efficient service.Originality/valueThe paper analyzes chatbots for customer service and presents the usability testing results of three chatbots implemented in MSMEs.
Graphene oxide (GO) nanosheets (0.5–2.0 phr) were incorporated into nitrile-butadiene rubber (NBR) to clarify how interfacial chemistry and dispersion control macroscopic performance. GO was synthesized by a modified Hummers method, and different filler concentrations of NBR/GO were prepared via solution–coagulation followed by sulfur vulcanization. Transmission electron microscopy (TEM) and atomic force microscopy (AFM) confirmed multilayer GO and best sheet dispersion at 1 phr, whereas 2 phr showed initial aggregation. Fourier-transform infrared spectroscopy (FTIR) confirmed that the NBR backbone and nitrile groups remained intact, while weak GO-derived C–O–C/C–O bands appeared at higher loadings. The C≡N band at ∼2,237 cm−1 preserved its position but showed a slight increase in bandwidth, consistent with the formation of a hydrogen-bonded interphase. X-ray diffraction (XRD) showed loss of GO periodicity in the rubber matrix. UV-Vis/Tauc analysis indicated a non-monotonic band gap (direct 3.01→3.13→3.11 eV; indirect 2.84→2.92→2.96 eV), arising from confinement at well-dispersed loadings and π–π stacking at higher loadings. Dielectric measurements (102–106 Hz, 20 °C–100 °C) evidenced a more stable ε′ for GO-filled samples, maximized at 1 phr. Mechanical testing showed simultaneous gains in tensile strength, tear resistance, and rebound elasticity at low GO loadings, while swelling and thermo-oxidative retention improved due to barrier effects and chain immobilization. Overall, ∼1 phr GO delivers the best structure–property balance, combining hydrogen-bond-mediated interfacial adhesion and optimal dispersion with stable dielectric behavior and reduced swelling/aging sensitivity; 2 phr yields the highest tensile value but also results in incipient aggregation and reduced dielectric stability.
Introduction:This study examines the effect of multi-walled carbon nanotube (MWCNT) loading on the dielectric behavior and triboelectric performance of polysiloxane (PS)-based nanocomposites for high-efficiency triboelectric nanogenerators (TENGs). Methods:Flexible PS/MWCNT films were fabricated using the doctor blading method and characterized by Raman spectroscopy and scanning electron microscopy (SEM). Broadband dielectric spectroscopy was employed to analyze frequency-dependent permittivity, interfacial polarization, and dielectric loss. TENGs were assembled in a vertical contact-separation mode using nylon as the positive triboelectric layer and evaluated under controlled temperature and humidity. Statistical error analysis (n = 3) was applied to ensure quantitative reliability. Results:A co-optimal MWCNT concentration of 0.03-0.05 wt% enhanced dielectric permittivity and interfacial charge trapping, improving triboelectric output while keeping conductive losses low. Higher loadings led to nanotube aggregation and increased dielectric loss, degrading device performance. Discussion/Conclusion:The study establishes a quantitative correlation between dielectric spectroscopy and triboelectric output, providing mechanistic insight into performance enhancement and degradation. This framework offers practical guidelines for designing PS-based nanocomposite TENGs for wearable electronics, self-powered sensors, and portable energy-harvesting applications.
The UN Decade on Ecosystem Restoration aims to stop biodiversity losses1. Approximately 60% of tropical forests have already been lost or severely degraded2, making restoration essential to achieve conservation goals. Recovery trajectories of trees have been studied intensively3,4, but a comprehensive understanding of biodiversity recovery is lacking. Here we analyse recovery trajectories across trophic levels including 16 taxonomic groups from three kingdoms in a lowland tropical forest by investigating resistance to perturbation, recovery times and return rates to old-growth forest conditions. Abundance and diversity regained more than 90% and composition approximately 75% similarity to old-growth forests within 30 years, but full recovery takes several decades. Mobile animal communities acting as seed dispersers or pollinators had high resistance levels and recovered faster than trees or tree seedlings. Return rates contributed 1-2.5 times more than resistance to the recovery times of species composition. Taxon-specific recovery times could not be explained by simple mechanisms (life-history strategies, trophic level or mobility). We show the enormous potential of protecting naturally recovering secondary forests to stop and reverse biodiversity losses.
