Acta Microscopica

EDITORIAL

Gema Gonzalez — 2026-10-07

EDITORIAL

A Shared Journey, an Enduring Passion

Some chapters of life are measured in years; others are best understood through the people, the efforts, and the bonds that made them possible. My time at the helm of Acta Microscopica belongs to both. As I present Volume 35, published in 2026, and bring my tenure as Editor-in-Chief to a close, I look back on this long journey with gratitude, heartfelt emotion, and a profound sense of shared responsibility.

In September 2005, during the General Assembly of the Inter-American Committee of Electron Microscopy Societies (CIASEM), held in Havana, Cuba, I had the honor of being appointed Editor-in-Chief of this journal. I accepted this responsibility with enthusiasm and with the conviction that our community needed a forum of its own in which to communicate its research, exchange knowledge, and recognize the scientific work carried out in our region.

Sustaining and strengthening that forum has required continuous effort ever since. The transition to a digital format, inclusion in Scopus, and the maintenance of a regular publication schedule were important milestones. Behind each lay daily work, difficult decisions, and countless hours devoted to a task whose demands are not always visible in the pages of a journal. Every published volume is therefore a collective achievement.

One of the principles I have sought most firmly to uphold is that scientific knowledge should be accessible to everyone. Acta Microscopica has maintained an open-access model, with no fees to publish, read, or download its articles. This commitment has provided a forum for disseminating research in materials science and the biological sciences that uses microscopy as a tool for investigation. In our region, where access to resources and opportunities is unequal, keeping these doors open has particular significance.

For me, electron microscopy has been much more than a characterization technique. It is an essential part of my life as a researcher and an enduring source of wonder. The possibility of observing previously invisible structures, discovering new questions in an image, and moving closer to an understanding of matter and life continues to inspire the same excitement in me. This love of microscopy accompanied every year of my editorial work and gave meaning to the effort required to carry it forward.

None of this would have been possible alone. To the authors who entrusted their research to the journal, the reviewers who generously shared their time and expertise, and the readers who found knowledge in our pages that informed their work: thank you. I also extend my sincere appreciation to the members of the successive editorial boards for their commitment and their contributions to maintaining the quality and continuity of Acta Microscopica.

I am especially grateful to the members of the Venezuelan Society of Electron Microscopy. Their support, friendship, and words of encouragement sustained me throughout these years, including the most difficult times. Their confidence in me was an important source of strength to keep going.

I also wish to remember the colleagues who were part of this story and are no longer with us. Their contributions live on in the journal and in the memories of those of us who shared their enthusiasm for science. As this chapter draws to a close, their presence is still deeply felt.

Today, Acta Microscopica begins a new chapter under the leadership of Francisco Capani, whom CIASEM has appointed as its new Editor-in-Chief. I wish him every success and hope that he will find within our community the support and collaboration that this responsibility deserves.

I conclude my tenure with the satisfaction of having contributed to a project that belongs to all of us. It has been an honor to serve as the custodian of these pages over the years. As I step down from my editorial responsibilities, my bond with this community and my love of microscopy remain undiminished.

Thank you for making this journey possible and for sharing it with me.

Gema González
Outgoing Editor-in-Chief
Acta Microscopica

EDITORIAL

Un camino compartido, una pasión que permanece

Hay etapas de la vida que se miden en años y otras que se comprenden mejor a través de las personas, los esfuerzos y los afectos que las hicieron posibles. Mi tiempo al frente de Acta Microscopica pertenece a ambas. Al presentar el volumen 35, correspondiente a 2026, y cerrar mi gestión como editora en jefe, vuelvo la mirada sobre este largo camino con gratitud, emoción y un profundo sentido de responsabilidad compartida.

En septiembre de 2005, durante la Asamblea General del Comité Interamericano de Sociedades de Microscopía Electrónica (CIASEM), celebrada en La Habana, Cuba, recibí el honor de ser designada editora en jefe de esta revista. Acepté esa responsabilidad con entusiasmo y con la convicción de que nuestra comunidad necesitaba un espacio propio para comunicar sus investigaciones, intercambiar conocimientos y reconocer el trabajo científico realizado en la región.

Desde entonces, sostener y hacer crecer ese espacio ha sido una labor constante. La transición al formato digital, la indexación en Scopus y la continuidad de las publicaciones fueron hitos importantes. Detrás de cada uno hubo trabajo cotidiano, decisiones difíciles y muchas horas dedicadas a una tarea cuyos esfuerzos no siempre son visibles en las páginas de una revista. Cada volumen publicado representa, por ello, un logro colectivo.

Una de las convicciones que más he procurado preservar es que el conocimiento científico debe estar al alcance de todos. Acta Microscopica ha mantenido un modelo de acceso abierto, sin cargos para publicar ni para consultar o descargar sus artículos. Este compromiso ha permitido ofrecer un espacio de difusión para investigaciones en ciencias de materiales y ciencias biológicas que incorporan la microscopía como herramienta de estudio. Para nuestra región, donde el acceso a recursos y oportunidades es desigual, mantener abiertas estas puertas tiene un significado especial.

Para mí, la microscopía electrónica ha sido mucho más que una técnica de caracterización. Es una parte esencial de mi vida como investigadora y una fuente permanente de asombro. La posibilidad de observar estructuras antes invisibles, reconocer en una imagen nuevas preguntas y acercarnos a la comprensión de la materia y de la vida sigue despertando en mí la misma emoción. Ese amor por la microscopía acompañó cada año de mi labor editorial y dio sentido al esfuerzo necesario para continuar.

Nada de este recorrido habría sido posible en soledad. A los autores que confiaron sus investigaciones a la revista, a los revisores que compartieron generosamente su tiempo y su criterio, y a los lectores que encontraron en nuestras páginas conocimientos útiles para su trabajo: gracias. A los integrantes de los distintos comités editoriales, mi reconocimiento por su compromiso y por haber contribuido a sostener la calidad y la continuidad de Acta Microscopica.

Guardo una gratitud especialmente profunda hacia los miembros de la Sociedad Venezolana de Microscopía Electrónica. Su respaldo, cercanía y palabras de aliento me acompañaron durante todos estos años, también en los momentos de mayor dificultad. Su confianza fue una fuerza importante para seguir adelante.

Quiero recordar, asimismo, a los colegas que formaron parte de esta historia y que ya no están físicamente con nosotros. Sus aportes permanecen en la revista y en la memoria de quienes compartimos con ellos el entusiasmo por la ciencia. En este cierre, su presencia también se siente.

Hoy, Acta Microscopica inicia una nueva etapa bajo la dirección de Francisco Capani, designado por el CIASEM como nuevo editor en jefe. Le deseo el mayor de los éxitos y que encuentre en nuestra comunidad el apoyo y la colaboración que esta responsabilidad merece.

Concluyo mi gestión con la satisfacción de haber contribuido a un proyecto que pertenece a todos nosotros. Ha sido un honor cuidar de sus páginas durante estos años. Dejo la responsabilidad editorial, pero conservo intactos mi vínculo con esta comunidad y mi amor por la microscopía.

Gracias por haber hecho posible este camino y por haberlo compartido conmigo.

Gema González
Editora en jefe saliente
Acta Microscopica

PHOTOCHEMICAL DEGRADATION PATHWAYS OF LINEAR LOW DENSITY POLYETHYLENE REVEALED BY INTEGRATED FTIR, RAMAN, AND AI-ASSISTED SEM ANALYSIS

C. Reinoso — 2026-10-07

Linear low-density polyethylene (LLDPE) is the dominant polymer in agricultural films, mulch covers, and packaging throughout Ecuador and Latin America, where intensive agricultural economies drive high per-capita consumption. Its prolonged outdoor use under intense equatorial UV radiation accelerates photooxidative degradation, generating microplastic particles that have been detected in remote ecosystems including the Antarctic region, underscoring the global reach of local plastic degradation. LLDPE films were subjected to two parallel exposure regimes: (i) natural weathering on the rooftop of Yachay Tech University, Urcuquí, Ecuador, for up to 342 days, and (ii) accelerated UV irradiation in a laboratory chamber equipped with a 50 W LED source at 365 nm for up to 579 hours (~97 equivalent days, based on 6 active sunlight hours per day). Chemical and structural evolution was monitored by ATR-FTIR spectroscopy, Raman spectroscopy, and scanning electron microscopy (SEM). Carbonyl index (CI = A₁₇₁₅/A₁₄₆₃), crystallinity ratio (I₇₂₉/I₇₃₀), and Raman-derived conformational indices were calculated. AI-assisted image analysis was applied to SEM micrographs to quantify surface defect area fraction. Spectroscopic identification was supported by a polymer reference library of 18 pellet standards created in collaboration with the IAEA Marine Environment Laboratory, Monaco. Environmental weathering produced a carbonyl index of ~0.22 after 342 days, with strong linear kinetics (R² = 0.992), whereas 400 h (~67 equivalent days) of controlled UV irradiation yielded a maximum CI of ~0.08 (R² = 0.859). The crystallinity-related I₇₂₉/I₇3₀ ratio declined from ~1.70 to ~1.45, consistent with progressive disruption of crystalline domains. Raman spectroscopy confirmed conformational reorganization toward trans conformers and orthorhombic ordering. AI-assisted SEM analysis quantified defect area fractions increasing from 0.32% to 3.37% under ambient weathering and from 0.31% to 5.29% under UV irradiation. LLDPE photodegradation is a coupled oxidation–reorganization process involving carbonyl accumulation, chemi-crystallization, and progressive surface embrittlement that ultimately generates microplastic particles. Integrated ATR-FTIR, Raman, and AI-assisted SEM analysis provides a comprehensive multi-scale framework for predicting polymer service lifetimes and informing mitigation strategies.

ELECTROSPUN ZNO NANOFIBERS FROM PVA/ZINC NITRATE PRECURSORS: EFFECTS OF PRECURSOR CONCENTRATION

Sergio Pomaquiza — 2026-10-07

Electrospinning was used to prepare poly(vinyl alcohol) (PVA)/zinc nitrate hexahydrate [Zn(NO₃)₂·6H₂O] fibers to evaluate the influence of zinc nitrate concentration on their morphology. The ZN2, ZN4, and ZN6 formulations had initial Zn(NO₃)₂·6H₂O concentrations of 2%, 4%, and 6% w/v relative to the water volume and approximate final concentrations of 1.01%, 2.04%, and 3.09% w/v relative to the total precursor-mixture volume, respectively. The mixtures were electrospun for 2 h onto silicon substrates, and the resulting specimens were thermally treated at 500 °C for 6 h using a heating rate of 10 °C min⁻¹. Optical and scanning electron microscopy showed that ZN4 produced greater observed substrate coverage and a more interconnected fibrous network under the investigated conditions. In contrast, ZN2 generated heterogeneous deposits containing clusters, short needle-like structures, bundles, and agglomerates, whereas ZN6 produced sparse deposits containing bundles and curved or segmented features. Non-contact atomic force microscopy of ZN4 showed apparent fiber widths of approximately 1.5–2.0 µm before thermal treatment and 120–380 nm after treatment. Separately, non-electrospun powder products obtained by thermally treating ZN6 precursor-solution aliquots exhibited Raman bands near 100, 332, and 438 cm⁻¹ from 500 °C onward, consistent with the characteristic vibrational modes of wurtzite ZnO. Qualitative EDS measurements provided complementary evidence of zinc-containing material. The results demonstrate that precursor concentration substantially influences the coverage, interconnectivity, and heterogeneity of the deposited fibrous structures.

ELECTROSPUN POLYVINYL ALCOHOL - CHITOSAN FIBERS WITH CERIA NANOPARTICLES FOR ANTIBACTERIAL AND ANTIFUNGAL APPLICATIONS

Cristhian Lopez — 2026-10-07

Electrospun Poly(vinyl alcohol)/Chitosan (70/30) fibers embedded with cerium oxide nanoparticles (1 to 3 % w/v) were fabricated and evaluated as antimicrobial fibrous materials. Transmission electron microscopy confirmed CeO₂ nanoparticles with an average size of 10 nm. Incorporation of CeO₂induced a significant reduction in fiber diameter from 450 nm to 150 nm. Agar diffusion assays against Escherichia coli E. coli and Candida albicans C. albicans revealed inhibition zones of 11.21 mm and 22.86 mm, respectively. These results indicate that CeO₂ incorporation was the principal factor associated with the observed antimicrobial activity, while the polymer composition influenced the apparent diffusion-dependent response. The combination of electrospun PVA-chitosan fibers and cerium oxide nanoparticles exhibits preliminary antibacterial and antifungal activity on a single electrospun platform, with potential biomedical applications.

MELOCACTUS CURVISPINUS (CACTACEAE) AS AN INHIBITOR OF STEEL CORROSION

S.Y. Paredes-Dugarte — 2026-10-07

This research aims to investigate the potential of Melocactus curvispinus pulp extract as a “green inhibitor”, focusing on the electrochemical behavior of API-N80 steel in a saline solution (3.5% m/v NaCl) and 1 mol/L H₂SO, with extract concentrations of 5, 10, 15 and 20% (v/v), as an environmentally friendly approach to reducing the use of toxic corrosion inhibitors, which are harmful to both the environment and human health. To achieve this, electrochemical techniques including potentiodynamic polarization, morphological characterization by SEM and photochemical analysis via FTIR with polarity fractionation were employed. The results of the electrochemical measurements showed that the extract acts as a mixed-type inhibitor in both saline and acidic media. In the saline medium achieving a maximum inhibition efficiency of 83.89% at a concentration of 15%, whereas at a concentration of 20%, a reversal of the protective effect was observed, attributed to saturation of the metal/solution interface, which accelerated the corrosion process. In the case of the acidic medium achieving a maximum efficiency of 78% at 20% extract concentration, conforming to the Langmuir isotherm with a physisorption mechanism (ΔG_ads = -3.09 kJ/mol). SEM revealed the formation of a protective film in both media, which was denser and more compact in the saline medium than in the acidic one, correlating with the observed efficiency levels. FTIR analysis confirmed the presence of alkaloids, coumarins, saponins and pentacyclic triterpenes identified in the phytochemical tests. The research validates the M. curvispinus extract as a functional bio-inhibitor for N-80 steel in both aggressive environments, although its use is limited by industrial volumetric requirements.

ULTRASONIC CHARACTERIZATION OF AISI SAE 1045 STEEL SUBJECTED TO SUBCRITICAL SPHEROIDIZATION TREATMENT AT 700ºC

A. Cano — 2026-10-26

The aim of this study is to evaluate the microstructural changes, in particular the morphological changes of cementite, in an AISI 1045 steel treated at 700°C by means of optical and scanning electron microscopy and ultrasonic techniques. The ultrasonic evaluation was carried out using the pulse-echo contact technique and 5, 10, and 22 MHz transducers to determine the acoustic parameters such as longitudinal ultrasonic wave velocity and attenuation coefficient. The non-conventional ultrasonic evaluation also included the analysis of signals in frequency. The results obtained from the microstructural evaluation reveal the fracture of the cementite lamellae of the pearlite and an increase in the degree of spheroidization with the increase of the treatment time at subcritical temperature. Ultrasonic evaluation exhibited a decrease in the longitudinal wave velocity in the transient state of change of pearlite morphology. Also, an increase in longitudinal velocity with increasing degree of spheroidization was observed. In contrast, the attenuation coefficient measurements show a tendency to increase with heat treatment time and with the microstructural changes of the material caused by the heat treatment. On the other hand, the spectral analysis suggests higher energy loss with longer treatment times due to the phenomena of ultrasonic wave attenuation by scattering, as a result of the morphological change that occurs in the pearlitic colonies.