Biology subjects

Carvajal, M.

Publications and source records attributed to Carvajal, M..

4 recordsLinked to original sources

bioRxiv2026

High-density surface EMG grid enables non-invasive characterization of intrinsic hand muscles activity

Understanding the neuromuscular properties that allow dexterous manipulation of objects remains a major challenge in neurorehabilitation, largely due to the difficulty of characterizing intrinsic hand muscle activity. These muscles are small, densely packed, and anatomically complex, making selective recordings with intramuscular electromyography (EMG) technically demanding and impractical for comprehensive studies. In this work, we present a custom, high-density (HD) surface EMG grid designed to non-invasively capture activity from intrinsic hand muscles from both dorsal and palmar surfaces. We evaluated the quality and spatial selectivity of the recordings by directly comparing them with intramuscular EMG signals obtained from the dorsal and palmar interossei. Surface EMG signals corresponded closely to the intramuscular recordings, with high correlation values for all subjects and tasks. Double differential spatial filtering significantly improved selectivity, although some residual volume conduction remained. The dorsal grid primarily captured dorsal interossei activity, while the palmar grid was more sensitive to lumbrical activation. The palmar interossei recordings were spatially more varied, with the second palmar interosseous predominantly detected on the dorsal grid and the third and fourth on the palmar grid. Together, these results demonstrate that non-invasive HD surface EMG will allow more complete measurement of intrinsic muscle activity, to provide a better understanding of the complex relation between the intrinsic and extrinsic hand muscles during dexterous movements. This basic information will allow refinement of biomechanical hand models and prosthetic devices, and the development of biomimetic brain computer interfaces aimed at restoring natural hand function after neurological injury.

bioengineering↗

bioRxiv2026

Propagation mode shapes contrasting growth strategies through aquaporin networks in onion

Propagation mode strongly influences crop establishment, yet its impact on whole-plant transport strategies remains poorly understood. Here, we examined whether seed- and set-derived plants deploy contrasting aquaporin networks associated with different physiological behaviours in onion (Allium cepa L.). We combined genome-wide gene-family characterisation with transcriptomic, biochemical, and physiological analyses. Forty-eight aquaporin genes were identified and classified into four subfamilies (15 PIPs, 19 TIPs, 8 NIPs, and 6 SIPs), with evidence of lineage-specific expansion in the PIP1 and TIP2. Expression analyses revealed clear propagation-dependent patterns. Set-derived plants displayed higher expression of AcPIP1.1, several PIP2 isoforms and most TIP2 members in both roots and leaves, consistent with enhanced water and CO2 transport, higher stomatal conductance, transpiration, and photosynthetic rates. In contrast, seed-derived plants showed increased expression of specific PIPs, and several NIPs (AcNIP1.1, AcNIP3.1, AcNIP5.1, AcNIP5.2, and AcNIP2.1) associated with solute and H2O2 transport, coinciding with higher boron and hydrogen peroxide levels. These findings indicate that propagation origin is associated with alternative aquaporin-mediated transport strategies: set-derived plants favour a high-flux strategy that supports rapid growth, whereas seed-derived plants prioritize tighter internal regulation through solute redistribution and redox homeostasis. Our results provide a molecular-physiological framework linking propagation origin with resource-use strategies in onion. HighlightPropagation origin reprograms aquaporin expression in onion, generating contrasting hydraulic, metabolic and growth strategies. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=80 SRC="FIGDIR/small/728701v1_ufig1.gif" ALT="Figure 1"> View larger version (41K): org.highwire.dtl.DTLVardef@b07bc1org.highwire.dtl.DTLVardef@8cda01org.highwire.dtl.DTLVardef@13c843eorg.highwire.dtl.DTLVardef@e26fb_HPS_FORMAT_FIGEXP M_FIG C_FIG

plant biology↗

bioRxiv2026

Muscle-driven hand simulations emphasize the critical role of the extensor mechanism

Biomechanical simulations of complex hand motions remain scarce, due to challenges that span computation and data acquisition. Using a computer vision-based motion capture approach, a 23-degree of freedom musculoskeletal model, and direct collocation optimization, we performed muscle-driven simulations to track hand kinematics from 7 participants performing American Sign Language gestures. While proximal joints were tracked accurately, interphalangeal joint tracking was significantly worse, with a consistent flexion bias. Modifications to finger extensor muscle paths that incorporated the dual-inserting nature of the extensors improved accuracy, suggesting better representation of extensor force distribution across distal joints may be necessary for accurate hand simulations.

bioengineering↗

bioRxiv2024

ARTIC RSV amplicon sequencing reveals global RSV genotype dynamics.

Respiratory syncytial virus (RSV) is a leading cause of lower respiratory tract infections (LTRIs) in young children and adults over 65, contributing significantly to global healthcare burdens. With the recent approval of multiple pharmacological interventions for RSV, there is an increased demand for efficient, high-throughput sequencing methods to monitor RSV genetic diversity and any potential impact these interventions may have. Here we introduce two novel amplicon-based sequencing schemes designed for RSV A and B, optimised for integration with widespread existing ARTIC sequencing workflows. We demonstrate that these primer schemes can produce high quality genomes from RSV samples across the globe, with eight laboratories in five countries generating complete genomes on both Nanopore and Illumina sequencing platforms. The ability to effectively multiplex these RSV A and B primer schemes, enables streamlined, high-throughput sequencing without prior subtyping. Furthermore, these results provide a snapshot of the circulating diversity of RSV. Phylogenetic analysis of the 882 samples sequenced for this study suggests only minimal geographic clustering of RSV sequences, underscoring the global nature of RSV spread. It also highlights the distinct lineage dynamics seen between RSV A and B. This study represents an advancement in RSV genomics, providing robust tools for global sequencing efforts aimed at tracking RSV evolution and assessing the efficacy of new therapeutic interventions both rapidly and at scale.

genomics↗