Marisol Contreras Quiñones

Geopolymer mortars were produced from construction and demolition waste using a binary binder of recycled brick powder/recycled concrete powder (RBP/RCP = 70/30 wt%), activated with a hybrid alkaline solution (NaOH/Na₂SiO₃/KOH) and reinforced with sisal fibres at 0–2 wt%. Mechanical performance (compression and three-point bending) and microstructure–phase evolution (XRD, FTIR, SEM-EDS) were assessed after low-temperature curing. Sisal addition delivered a strength–toughness trade-off with a reproducible optimum at ~1.0–1.5 wt%; at 2.0 wt%, fibre clustering and connected porosity reduced the effective load-bearing section, penalising flexure more than compression. Microstructural evidence indicates coexistence and co-crosslinking of N-A-S-H and C-(A)-S-H gels—enabled by Ca from RCP—leading to matrix densification and improved fibre–matrix anchorage. Fractographic features (tortuous crack paths, bridging, and extensive pull-out at ~1.5 wt%) are consistent with an extended post-peak response and higher fracture work without compromising early-age strength. This study achieves the following: (i) it identifies a practical reinforcement window for sisal in RBP/RCP geopolymers, (ii) it links gel chemistry and interfacial phenomena to macroscopic behaviour, and (iii) it distils processing guidelines (gradual addition, workability control, gentle deaeration, and constant A/S) that support reproducibility. These outcomes provide a replicable, low-embodied-CO₂ route to fibre-reinforced geopolymer mortars derived from CDW for non-structural and semi-structural applications where flexural performance and post-peak behaviour are critical.

Geopolymer mortars were produced from recycled concrete powder (RCP) and recycled brick powder (RBP) at a 30/70 wt% ratio, activated with a hybrid alkaline solution (NaOH/Na₂SiO₃/KOH) and reinforced with sisal (Agave) fibers at 0–2 wt%. Mechanical performance (compression and flexural) and microstructure–phase evolution were as-sessed by XRD, FTIR, and SEM-EDS after low-temperature curing. Sisal addition de-livered a strength–toughness balance, with an intermediate dosage (~1–1.5 wt%) providing the best overall performance; higher dosages induced packing loss and fiber clustering. Microstructural evidence indicates the coexistence and co-crosslinking of N-A-S-H and C-(A)-S-H gels promoted by the RCP, which densifies the matrix and enhances fiber–matrix anchorage. Fractographic features support a crack-bridging/pull-out mechanism responsible for the improvement without penaliz-ing early-age strength. The study identifies a practical advantage of sisal reinforcement in RCP/RBP geopolymer mortars and links it to gel chemistry and interfacial phenom-ena, providing a reproducible pathway toward fiber-reinforced, low-embodied-carbon geopolymers derived from construction and demolition waste and suitable for durable construction applications.

The National University of Trujillo turned 200 years old on May 10, 2024 and proposes the analysis of its behavior based on environmental care, botany and natural medicine. To do this, a multidisciplinary team developed three approaches: scientific, legal and educational. Analyzing its botanical wealth within the campus, reference centers that it has, external and internal regulations that havedetermined its activities and the curricular dynamics associated with the subject; It is concluded, the existence of 181 plant species (90 medicinal) within the campus; five reference centers whose purpose is the study, research and preservation in situ and ex situ of biodiversity; a policy and lines of research in response to university laws and quality models; and recognition of the School of Biological Sciences for the training of biologists with training in caring for the environment and national botany.

Bacterial cellulose is a biomaterial known for its physical and mechanical properties, including its high mechanical strength, water retention capacity, and biocompatibility. Its production from various carbohydrates has been widely studied, aiming to find more efficient and cost-effective culture media. This study investigated the production of bacterial cellulose from agroindustrial asparagus peel waste by Komagataeibacter rhaeticus QK23. A strain of QK23 was isolated and cultivated from a kombucha tea, identified based on morphological and molecular characteristics using the 16S rRNA gene. The waste was hydrolyzed and converted into fermentable sugars. Using the response surface methodology, the inoculum dose (1–20%) and incubation time (3–25 days) were evaluated concerning bacterial cellulose yield. The results demonstrated that with an optimal inoculum dose of 10.5% and an incubation time of 25 days, a production of 2.57 g/L was achieved. It was characterized as similar to type I cellulose, exhibiting a high degree of crystallinity (81.89%) and suitable morphological properties, evidenced by a fiber size of 178 nm and a surface roughness of 27.05 nm. Converting asparagus waste into bacterial cellulose is a sustainable and effective strategy that promotes the development of advanced biomaterials in biotechnology research.

EFECTO DE DIFERENTES SURFACTANTES SOBRE LARVAS III DE SPODOPTERA FRUGIPERDA SMITH BAJO CONDICIONES DE LABORATORIO Y DE CAMPO

CITOTOXICIDAD Y GENOTOXICIDAD DE NANOPARTÍCULAS DE ORO SINTETIZADAS POR ABLACIÓN LÁSER SOBRE ALLIUM CEPA L. (AMARYLLIDACEAE)