Morphology characterization of dendrites on lithium metal electrodes by NMR spectroscopy.

Despite the considerable potential offered by lithium metal's high capacity for rechargeable batteries, challenges such as dendrite formation and safety concerns persist. As strategies continue to advance in dendrite management, the demand for efficient monitoring tools becomes increasingly pronounced. In this study, we delve into the characterization of dendrites, elucidating the influence of microstructure morphology on the NMR spectrum using a combination of simulations and experiments. Systematic variations in various geometrical parameters highlight dendrite density as a pivotal distinguishing feature. Furthermore, the investigation explores the effectiveness of a pulse sequence in selectively exciting microstructures over the bulk, providing valuable insights into mitigating dendrite-related challenges in lithium-metal batteries.

Catéter epidural seccionado: reporte de un caso y revisión de literatura / Sectioned epidural catheter: a case report and review of literature / Ruptura de cateter epidural: relato de caso e revisão da literatura

Resumen: La ruptura y retención de un fragmento de catéter peridural es una complicación poco frecuente de la analgesia epidural. Si bien generalmente requiere una conducta expectante con evolución sin mayores complicaciones, su importancia está dada por la escasa evidencia en cuanto al manejo, teniendo en cuenta que puede derivar en una intervención neuroquirúrgica, con sus riesgos y complicaciones. Exponemos el caso de una paciente que tuvo como complicación la ruptura y retención de un fragmento de catéter peridural durante la colocación del mismo para analgesia del parto.

Summary: Rupture and retention of an epidural catheter fragment is a rare complication of epidural analgesia. Although it generally requires expectant management and evolves without major complications, the event is important given the lack of evidence regarding treatment and considering it can lead to a neurosurgical intervention, what involves risks and complications. The study describes the case of a patient whose complication was the rupture and retention of a fragment of an epidural catheter during labor analgesia.

Resumo: A ruptura e retenção de um fragmento de cateter epidural é uma complicação rara da analgesia epidural. Embora geralmente exija uma gestão expectante com evolução sem grandes complicações, a importância é dada pela escassa evidência relativa ao manejo, considerando que pode levar à uma intervenção neurocirúrgica, com os correspondentes riscos e complicações. Apresentamos o caso de uma paciente cuja complicação foi a ruptura e retenção de um fragmento de cateter epidural durante sua colocação para analgesia do parto.

Ultrasensitive Genetically Encoded Indicator for Hydrogen Peroxide Identifies Roles for the Oxidant in Cell Migration and Mitochondrial Function.

Hydrogen peroxide (H2O2) is a key redox intermediate generated within cells. Existing probes for H2O2 have not solved the problem of detection of the ultra-low concentrations of the oxidant: these reporters are not sensitive enough, or pH-dependent, or insufficiently bright, or not functional in mammalian cells, or have poor dynamic range. Here we present HyPer7, the first bright, pH-stable, ultrafast, and ultrasensitive ratiometric H2O2 probe. HyPer7 is fully functional in mammalian cells and in other higher eukaryotes. The probe consists of a circularly permuted GFP integrated into the ultrasensitive OxyR domain from Neisseria meningitidis. Using HyPer7, we were able to uncover the details of H2O2 diffusion from the mitochondrial matrix, to find a functional output of H2O2 gradients in polarized cells, and to prove the existence of H2O2 gradients in wounded tissue in vivo. Overall, HyPer7 is a probe of choice for real-time H2O2 imaging in various biological contexts.

Mining for protein S-sulfenylation in Arabidopsis uncovers redox-sensitive sites.

Hydrogen peroxide (H2O2) is an important messenger molecule for diverse cellular processes. H2O2 oxidizes proteinaceous cysteinyl thiols to sulfenic acid, also known as S-sulfenylation, thereby affecting the protein conformation and functionality. Although many proteins have been identified as S-sulfenylation targets in plants, site-specific mapping and quantification remain largely unexplored. By means of a peptide-centric chemoproteomics approach, we mapped 1,537 S-sulfenylated sites on more than 1,000 proteins in Arabidopsis thaliana cells. Proteins involved in RNA homeostasis and metabolism were identified as hotspots for S-sulfenylation. Moreover, S-sulfenylation frequently occurred on cysteines located at catalytic sites of enzymes or on cysteines involved in metal binding, hinting at a direct mode of action for redox regulation. Comparison of human and Arabidopsis S-sulfenylation datasets provided 155 conserved S-sulfenylated cysteines, including Cys181 of the Arabidopsis MITOGEN-ACTIVATED PROTEIN KINASE4 (AtMAPK4) that corresponds to Cys161 in the human MAPK1, which has been identified previously as being S-sulfenylated. We show that, by replacing Cys181 of recombinant AtMAPK4 by a redox-insensitive serine residue, the kinase activity decreased, indicating the importance of this noncatalytic cysteine for the kinase mechanism. Altogether, we quantitatively mapped the S-sulfenylated cysteines in Arabidopsis cells under H2O2 stress and thereby generated a comprehensive view on the S-sulfenylation landscape that will facilitate downstream plant redox studies.

Magnetic Resonance Imaging in Situ Visualization of an Electrochemical Reaction under Forced Hydrodynamic Conditions.

Magnetic resonance imaging (MRI) has proven to be a powerful tool for the characterization and investigation of in situ chemical reactions. This is more relevant when dealing with complex systems, where the spatial distribution of the species, partition equilibrium, flow patterns, among other factors have a determining effect over mass transport and therefore over the reaction rate. The advantage of MRI is that it provides spatial information in a noninvasive way and does not require any molecular sensor or sample extraction. In this work, MRI is used to fully characterize an electrochemical reaction under forced hydrodynamic conditions. Reaction rates, flow patterns, and quantitative concentration of the chemical species involved are spatially monitored in situ in a complex system that involves metallic pieces and a heterogeneous cementation reaction. Experimental data are compared with numerical simulations.