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J. Staforelli-Vivanco

Publications and source records attributed to J. Staforelli-Vivanco.

4 recordsLinked to original sources

Automated Palynological Analysis System: Integrating Deep Metric Learning and $U^{2}$-Net Detection in $H\infty$ bright field microscopy

Traditional melissopalynology is a time-consuming and subjective process, often taking 4-6 hours per sample. We present an automated, high-throughput microscopy system that integrates $H\infty$ robust mechanical control with advanced deep learning pipelines for the precise counting, classification, and morphological analysis of pollen grains from Bio Bio region in south central territory in Chile. Our system employs $U^{2}$-Net for salient object detection and a DINOv2 Vision Transformer backbone trained via Deep Metric Learning for classification. By integrating Gradient-Weighted Attention, the model provides human-interpretable texture and diagnostic feature annotations. The system achieves a 95.8$\%$ classification recall and a 6x processing speedup compared to manual expert analysis.

cs.CV

Optical Manipulation of Erythrocytes via Evanescent Waves: Assessing Glucose-Induced Mobility Variations

This study investigates the dynamics of red blood cells (RBCs) under the influence of evanescent waves generated by total internal reflection (TIR). Using a 1064 nm laser system and a dual-chamber prism setup, we quantified the mobility of erythrocytes in different glucose environments. Our methodology integrates automated tracking via TrackMate\c{opyright} to analyze over 60 trajectory sets. The results reveal a significant decrease in mean velocity, from 11.8 {\mu}m/s in 5 mM glucose to 8.8 {\mu}m/s in 50 mM glucose (p = 0.019). These findings suggest that evanescent waves can serve as a non-invasive tool to probe the mechanical properties of cell membranes influenced by biochemical changes.

physics.optics

Three-Dimensional Volumetric Reconstruction of Native Chilean Pollen via Lens-Free Digital In-line Holographic Microscopy

This study presents a methodology for the three-dimensional volumetric reconstruction and morphological characterization of native Chilean pollen grains using lens-free Digital In-line Holographic Microscopy (DLHM). A 532 nm point source, a 3.45 $\mu$m pixel pitch CMOS sensor and a source--sample distance of $0.46$ mm with a $25$ mm stand-off give a magnification of $\simeq 55\times$ and an effective pixel of 62.9 nm. Wavefronts of \textit{Anthemis cotula}, \textit{Gevuina avellana} and \textit{Conium maculatum} were reconstructed by the Kirchhoff-Helmholtz transform, yielding volumes from $3780.2 \pm 18$ to $4320.5 \pm 15$ $\mu$m$^3$ and sphericities from $0.76 \pm 0.03$ for the echinate \textit{A. cotula} to $0.89 \pm 0.02$ for \textit{G. avellana}. Three independent targets make these reconstructions traceable. Certified polystyrene microspheres ($\varnothing = 20.0$ $\mu$m) make the source--sample distance an optically retrieved quantity, the 2.5D height map returning $2068$ $\mu$m$^3$ against an analytical $2094.4$ $\mu$m$^3$. A human erythrocyte, reconstructed with a haemoglobin refractive-index increment taken from the literature rather than fitted, returns $88.9$ fL with a $2.36$ $\mu$m rim and a $1.03$ $\mu$m dimple, within physiological range. Finally, transport-of-intensity retrieval on bright-field micrographs from a separate, independently calibrated instrument reproduces the projected morphology of \textit{G. avellana}, though no volume follows from it. These results support label-free "digital fingerprints" for automated melissopalynology in a South American biodiversity hotspot.

physics.optics

Effects of 2.45 GHz radiofrequency upon Leuconostoc mesenteroides Glucose-6-phosphate dehydrogenase enzymatic activity

In this report we evaluate the effect in the enzyme activity of Glucose 6-phosphate Dehydrogenase from Leuconostoc mesenteroides by irradiation with 2.45 GHz radiofrequency at a power output of 0.1 W during a 91 h period. The results show that the RF irradiation preserves the activity of treated samples of this enzyme with respect to a non-treated sample that instead suffer an increased rate of activity loss. Our estimates indicate that the enzyme activation is due to a non-thermal effect. The results are consistent with reports about the effect of 2.45 GHz radiation upon other enzymatic systems.

q-bio.BM