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1.
Artículo en Inglés | MEDLINE | ID: mdl-39177772

RESUMEN

The crystal structures of two coordination compounds, (acetato-κO)(2,2'-bipyridine-κ2N,N')(1,10-phenanthroline-κ2N,N')copper(II) acetate hexahydrate, [Cu(C2H3O2)(C10H8N2)(C12H8N2)](C2H3O2)·6H2O or [Cu(bipy)(phen)Ac]Ac·6H2O, and (acetato-κO)bis(2,2'-bipyridine-κ2N,N')copper(II) acetate-acetic acid-water (1/1/3), [Cu(C2H3O2)(C10H8N2)2](C2H3O2)·C2H4O2·3H2O or [Cu(bipy)2Ac]Ac·HAc·3H2O, are reported and compared with the previously published structure of [Cu(phen)2Ac]Ac·7H2O (phen is 1,10-phenanthroline, bipy for 2,2'-bipyridine, ac is acetate and Hac is acetic acid). The geometry around the metal centre is pentacoordinated, but highly distorted in all three cases. The coordination number and the geometric distortion are both discussed in detail, and all complexes belong to the space group P\overline{1}. The analysis of the geometric parameters and the Hirshfeld surface properties dnorm and curvedness provide information about the metal-ligand interactions in these complexes and allow comparison with similar systems.

4.
Anal Chem ; 2024 Aug 16.
Artículo en Inglés | MEDLINE | ID: mdl-39151027

RESUMEN

Parchment is an ancient writing support formed from dehaired animal skins. Its manufacture comprises a series of liming and scraping steps before being stretched and dried under tension. Historical parchment represents a valuable source of cultural heritage which, until now, has limited investigations to noninvasive analyses to infer ink composition, degradation, or physical changes over time. We highlight the prospect of the molecular and isotope compositions of animal lipids from parchment as an untapped record of its production and the animal's diet and environment. We report a minimally invasive, total lipid extraction aided by a vacuum for historical parchments. The quantitative and qualitative compositions of lipid extracts obtained using this method are compared with those obtained using invasive sampling for nine sacrificial membranes dated 1765-1825 CE. This extraction method is then applied to membranes from the Chancery Parliament Rolls (1814-1820 CE) held by The National Archives, UK to obtain lipids and derive taxonomic and dietary information using their stable carbon isotope compositions. This novel vacuum-aided extraction allows, for the first time, animal lipids to be obtained from parchment minimally invasively, paving the way for dietary and paleoclimate studies using this well-dated and common material.

5.
J Surg Res ; 302: 364-375, 2024 Aug 16.
Artículo en Inglés | MEDLINE | ID: mdl-39153357

RESUMEN

INTRODUCTION: Abdominal adhesions represent a chronic postsurgical disease without reliable prophylaxis. Animal modeling has been a cornerstone of novel therapeutic development but has not produced reliable clinical therapies for prevention of adhesive small bowel obstruction. The purpose of this scoping review is to analyze animal models for abdominal adhesion generation by key considerations of external validity (i.e., fidelity, homology, and discrimination). METHODS: A literature review was performed in accordance with the Preferred Reporting Items for Systematic Reviews Extension for Scoping Reviews guidelines. Peer-reviewed publications were included that described the development or quality assessment of experimental animal models for abdominal adhesions with inclusion of a scoring system. Studies that focused on treatment evaluation, implantation of surgical devices, models of nonsurgical etiologies for abdominal adhesions, non-in vivo modeling, and investigations involving human subjects were excluded. RESULTS: Four hundred and fifteen (n = 415) articles were identified by prespecified search criteria. Of these, 13 studies were included for review. CONCLUSIONS: Translation of investigational therapeutics for abdominal adhesion prevention is dependent upon high-quality experimental animal models that reproduce the clinical adhesions seen in the operating room as a disease of the entire abdomen.

6.
Chemistry ; : e202402468, 2024 Aug 07.
Artículo en Inglés | MEDLINE | ID: mdl-39109881

RESUMEN

Enzymes turnover substrates into products with amazing efficiency and selectivity and as such have great potential for use in biotechnology and pharmaceutical applications. However, details of their catalytic cycles and the origins surrounding the regio- and chemoselectivity of enzymatic reaction processes remain unknown, which makes the engineering of enzymes and their use in biotechnology challenging. Computational modelling can assist experimental work in the field and establish the factors that influence the reaction rates and the product distributions. A popular approach in modelling is the use of quantum mechanical cluster models of enzymes that take the first- and second coordination sphere of the enzyme active site into consideration. These QM cluster models are widely applied but often the results are dependent on model choice and selection. Herein, we show that QM cluster models can produce highly accurate results that reproduce experimental product distributions and free energies of activation, regarded that large cluster models with >300 atoms are used. In this tutorial review, we give general guidelines on the set-up and applications of the QM cluster method and discuss its accuracy and reproducibility. Finally, several representative QM cluster model examples on metal-containing enzymes are presented, which highlight the strength of the approach.

7.
Phys Chem Chem Phys ; 2024 Aug 09.
Artículo en Inglés | MEDLINE | ID: mdl-39119661

RESUMEN

A theoretical framework to explain how interactions between redox mediators (RMs) and electrolyte components impact electron transfer kinetics, thermodynamics, and catalytic efficiency is presented. Specifically focusing on ionic association, 2,5-di-tert-butyl-1,4-benzoquinone (DBBQ) is used as a case study to demonstrate these effects. Our analytical equations reveal how the observed redox couple's potential and electron transfer rate constants evolve with Li+ concentration, resulting from different redox activity mechanisms. Experimental validation by cyclic voltammetry measurements shows that DBBQ binds to three Li+ ions in its reduced state and one Li+ ion in its neutral form, leading to a maximum in the electron transfer kinetic constant at around 0.25 M. The framework is extended to account for other phenomena that can play an important role in the redox reaction mechanisms of RMs. The effect of Li+ ion solvation and its association with the supporting salt counteranion on the redox processes is considered, and the role of "free Li+" concentration in determining the electrochemical behaviour is emphasized. The impact of Li+ concentration on oxygen reduction reaction (ORR) catalysis was then explored, again using DBBQ and modelling the effects of the Li+ concentration on electron transfer and catalytic kinetics. We show that even though the observed catalytic rate constant increases with Li+ concentration, the overall catalysis can become more sluggish depending on the electron transfer pathway. Cyclic voltammograms are presented as illustrative examples. The strength of the proposed theoretical framework lies in its adaptability to a wider range of redox mediators and their interactions with the various electrolyte components and redox active molecules such as oxygen. By understanding these effects, we open up new avenues to tune electron transfer and catalytic kinetics and thus improve the energy efficiency and rate capability of Li-O2 batteries. Although exact results may not transfer to different solvents, the predictions of our model will provide a starting point for future studies of similar systems, and the model itself is easily extensible to new chemistries.

8.
Biol Lett ; 20(8): 20240135, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-39106948

RESUMEN

Increased attraction to humans and their objects often arises after repeated and positive human-wildlife encounters (e.g. food provided in tourist settings). The causes of this 'over-attraction', which may result from a learned association between humans and food, are still poorly studied in wild animals. Understanding the influence of humans on animals' responses is yet crucial to prevent negative effects (e.g. aggression). We presented three novel objects to two groups of free-ranging brown skuas (Catharacta antarctica ssp. lonnbergi) in the remote sub-Antarctic, where their habitats show no or minimal human disturbance. Skuas in one group (Verte) had previously participated in repeated food-rewarded behavioural and cognitive tasks with a human experimenter; skuas in the other group (Ratmanoff) had never done so. Objects consisted of (i) one natural-food-resembling object (plastic fish), (ii) one anthropogenic food object (real cake slice), and (iii) one anthropogenic non-food object (yellow glove). Verte group skuas approached the human experimenter and pecked significantly more and sooner at novel objects. Human-food association may have thus resulted in increased attraction to humans and novelty exploration in previously naive brown skuas, making this species a useful model for investigating the consequences of experience with humans on wildlife behaviour.


Asunto(s)
Conducta Exploratoria , Animales , Humanos , Islas , Masculino , Alimentos , Femenino , Interacción Humano-Animal , Conducta Alimentaria , Conducta Animal , Regiones Antárticas
9.
Molecules ; 29(15)2024 Jul 28.
Artículo en Inglés | MEDLINE | ID: mdl-39124967

RESUMEN

The development of new methods of identification of active pharmaceutical ingredients (API) is a subject of paramount importance for research centers, the pharmaceutical industry, and law enforcement agencies. Here, a system for identifying and classifying pharmaceutical tablets containing acetaminophen (AAP) by brand has been developed. In total, 15 tablets of 11 brands for a total of 165 samples were analyzed. Mid-infrared vibrational spectroscopy with multivariate analysis was employed. Quantum cascade lasers (QCLs) were used as mid-infrared sources. IR spectra in the spectral range 980-1600 cm-1 were recorded. Five different classification methods were used. First, a spectral search through correlation indices. Second, machine learning algorithms such as principal component analysis (PCA), support vector classification (SVC), decision tree classifier (DTC), and artificial neural network (ANN) were employed to classify tablets by brands. SNV and first derivative were used as preprocessing to improve the spectral information. Precision, recall, specificity, F1-score, and accuracy were used as criteria to evaluate the best SVC, DEE, and ANN classification models obtained. The IR spectra of the tablets show characteristic vibrational signals of AAP and other APIs present. Spectral classification by spectral search and PCA showed limitations in differentiating between brands, particularly for tablets containing AAP as the only API. Machine learning models, specifically SVC, achieved high accuracy in classifying AAP tablets according to their brand, even for brands containing only AAP.


Asunto(s)
Acetaminofén , Aprendizaje Automático , Análisis de Componente Principal , Espectrofotometría Infrarroja , Comprimidos , Acetaminofén/química , Acetaminofén/análisis , Comprimidos/química , Espectrofotometría Infrarroja/métodos , Redes Neurales de la Computación , Algoritmos , Máquina de Vectores de Soporte
10.
Artículo en Inglés | MEDLINE | ID: mdl-39088702

RESUMEN

ABSTRACT: This case report characterizes a unique way in which suicide was accomplished through ingestion of chemicals typically used to create acrylic fingernails that resulted in death. Ethyl methacrylate and acrylic powder are commonly combined to form acrylic nails in nail salons. The process of applying acrylic nails utilizes each substance by mixing both before it typically solidifies within seconds of combining the two compounds. Ingestion of these compounds has not been previously described within the medical literature. The decedent was a nail technician at a local salon. He was found unresponsive in his yard which led to a 911 call. At the scene, a mostly empty 16-oz bottle of ethyl methacrylate, a chemical used at the salon where he worked, was found. At autopsy, the decedent's body had a strong chemical odor consistent with odors present at nail salons. Significant gastrointestinal tract damage was seen including discoloration within the esophagus, and the stomach contained a molded, hardened nail compound. The cause of death was ruled as complications of nail acrylic powder and liquid ethyl methacrylate ingestion. This case shows the unusual findings seen at autopsy from a decedent who committed suicide by ingestion of ethyl methacrylate with acrylic powder.

11.
Opt Lett ; 49(13): 3705-3708, 2024 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-38950247

RESUMEN

Circular dichroism second harmonic generation microscopy (CDSHG) is a powerful imaging technique, which allows three-dimensional visualization of collagen fibril orientation in tissues. However, recent publications have obtained contradictory results on whether CDSHG can be used to reveal the relative out-of-plane polarity of collagen fibrils. Here we compare CDSHG images of unstained tendon and tendon which has been stained with hematoxylin and eosin. We find significant differences in the CDSHG between these two conditions, which explain the recent contradictory results within the literature.


Asunto(s)
Dicroismo Circular , Colágeno , Tendones , Colágeno/química , Tendones/diagnóstico por imagen , Tendones/química , Animales , Coloración y Etiquetado , Microscopía de Generación del Segundo Armónico/métodos
12.
Am Surg ; : 31348241265142, 2024 Jul 21.
Artículo en Inglés | MEDLINE | ID: mdl-39033341

RESUMEN

Introduction: Whole blood (WB) is associated with improved mortality while lowering blood product utilization. Furthermore, statin medications are associated with favorable outcomes in traumatic brain injury and risk reduction of venous thromboembolism. However, the use of statin medications has not been evaluated in those receiving WB. The objective of this study is to determine the effects of pre-injury statin exposure on patients receiving WB.Methods: Patients that underwent WB first resuscitation and received pre-injury statins were compared to those that did not receive pre-injury statins. Demographics as well as complication rates, blood product transfusion volumes, and mortality were evaluated. Univariate and multivariable analyses were used to determine independent predictors of mortality.Results: In the study period, 785 patients received WB as part of their resuscitation. One hundred and thirty five patients (17.3%) took statin medications prior to injury. Patients that were exposed to a pre-injury statin had a lower mortality rate than those that were not exposed (21.5% vs 32.5%, P = .01). After adjusting for imbalances, age, ISS, Glasgow Coma Scale, admission systolic blood pressures, and pre-injury statin use were independent predictors of mortality following multiple logistic regression. When evaluating outcomes based on statin intensity, the use of high-intensity statins was associated with lower mortality (OR: .37, 95% CI: .13-.93), whereas moderate and low-intensity statins were not.Conclusion: In patients resuscitated with WB, pre-injury statins use was associated with improved outcomes. Specifically, patients that received high-intensity pre-injury statins appeared to be the population that benefited.

13.
Bone Joint J ; 106-B(8): 842-848, 2024 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-39084641

RESUMEN

Aims: Vascular compromise due to arterial injury is a rare but serious complication of a proximal humeral fracture. The aims of this study were to report its incidence in a large urban population, and to identify clinical and radiological factors which are associated with this complication. We also evaluated the results of the use of our protocol for the management of these injuries. Methods: A total of 3,497 adult patients with a proximal humeral fracture were managed between January 2015 and December 2022 in a single tertiary trauma centre. Their mean age was 66.7 years (18 to 103) and 2,510 (72%) were female. We compared the demographic data, clinical features, and configuration of those whose fracture was complicated by vascular compromise with those of the remaining patients. The incidence of vascular compromise was calculated from national population data, and predictive factors for its occurrence were investigated using univariate analysis. Results: A total of 18 patients (0.5%) had a proximal humeral fracture and clinical evidence of vascular compromise, giving an annual incidence of 0.29 per 100,000 of the population. Their mean age was 68.7 years (45 to 92) and ten (56%) were female. Evidence of a mixed pattern neurological deficit (brachial plexus palsy) (odds ratio (OR) 380.6 (95% CI 85.9 to 1,685.8); p < 0.001), complete separation of the proximal shaft from the humeral head with medial displacement (OR 39.5 (95% CI 14.0 to 111.8); p < 0.001), and a fracture-dislocation (OR 5.0 (95% CI 1.6 to 15.3); p = 0.015) were all associated with an increased risk of associated vascular compromise. A policy of reduction and fixation of the fracture prior to vascular surgical intervention had favourable outcomes without vascular sequelae. Conclusion: The classic signs of distal ischaemia are often absent in patients with proximal injuries to major vessels. We were able to identify specific clinical and radiological 'red flags' which, particularly when present in combination, should increase the suspicion of a fracture with an associated vascular injury, and facilitate early diagnosis and appropriate combined orthopaedic and vascular intervention.


Asunto(s)
Fracturas del Hombro , Lesiones del Sistema Vascular , Humanos , Femenino , Anciano , Masculino , Fracturas del Hombro/epidemiología , Fracturas del Hombro/diagnóstico por imagen , Fracturas del Hombro/complicaciones , Persona de Mediana Edad , Anciano de 80 o más Años , Adulto , Incidencia , Lesiones del Sistema Vascular/epidemiología , Lesiones del Sistema Vascular/etiología , Estudios Retrospectivos , Adolescente , Adulto Joven
14.
Brain ; 147(8): 2668-2679, 2024 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-39074992

RESUMEN

Variants in seven genes (LRRK2, GBA1, PRKN, SNCA, PINK1, PARK7 and VPS35) have been formally adjudicated as causal contributors to Parkinson's disease; however, individuals with Parkinson's disease are often unaware of their genetic status since clinical testing is infrequently offered. As a result, genetic information is not incorporated into clinical care, and variant-targeted precision medicine trials struggle to enrol people with Parkinson's disease. Understanding the yield of genetic testing using an established gene panel in a large, geographically diverse North American population would help patients, clinicians, clinical researchers, laboratories and insurers better understand the importance of genetics in approaching Parkinson's disease. PD GENEration is an ongoing multi-centre, observational study (NCT04057794, NCT04994015) offering genetic testing with results disclosure and genetic counselling to those in the US (including Puerto Rico), Canada and the Dominican Republic, through local clinical sites or remotely through self-enrolment. DNA samples are analysed by next-generation sequencing including deletion/duplication analysis (Fulgent Genetics) with targeted testing of seven major Parkinson's disease-related genes. Variants classified as pathogenic/likely pathogenic/risk variants are disclosed to all tested participants by either neurologists or genetic counsellors. Demographic and clinical features are collected at baseline visits. Between September 2019 and June 2023, the study enrolled 10 510 participants across >85 centres, with 8301 having received results. Participants were: 59% male; 86% White, 2% Asian, 4% Black/African American, 9% Hispanic/Latino; mean age 67.4 ± 10.8 years. Reportable genetic variants were observed in 13% of all participants, including 18% of participants with one or more 'high risk factors' for a genetic aetiology: early onset (<50 years), high-risk ancestry (Ashkenazi Jewish/Basque/North African Berber), an affected first-degree relative; and, importantly, in 9.1% of people with none of these risk factors. Reportable variants in GBA1 were identified in 7.7% of all participants; 2.4% in LRRK2; 2.1% in PRKN; 0.1% in SNCA; and 0.2% in PINK1, PARK7 or VPS35 combined. Variants in more than one of the seven genes were identified in 0.4% of participants. Approximately 13% of study participants had a reportable genetic variant, with a 9% yield in people with no high-risk factors. This supports the promotion of universal access to genetic testing for Parkinson's disease, as well as therapeutic trials for GBA1 and LRRK2-related Parkinson's disease.


Asunto(s)
Pruebas Genéticas , Glucosilceramidasa , Proteína 2 Quinasa Serina-Treonina Rica en Repeticiones de Leucina , Enfermedad de Parkinson , alfa-Sinucleína , Humanos , Enfermedad de Parkinson/genética , Enfermedad de Parkinson/diagnóstico , Pruebas Genéticas/métodos , Masculino , Femenino , Glucosilceramidasa/genética , Proteína 2 Quinasa Serina-Treonina Rica en Repeticiones de Leucina/genética , alfa-Sinucleína/genética , Anciano , Persona de Mediana Edad , Ubiquitina-Proteína Ligasas/genética , Proteínas Quinasas/genética , Proteína Desglicasa DJ-1/genética , Proteínas de Transporte Vesicular/genética , América del Norte , Variación Genética/genética , Predisposición Genética a la Enfermedad/genética , Adulto , Revelación , Asesoramiento Genético , Canadá , Estados Unidos
15.
Sci Rep ; 14(1): 17528, 2024 07 30.
Artículo en Inglés | MEDLINE | ID: mdl-39080444

RESUMEN

HistoLens is an open-source graphical user interface developed using MATLAB AppDesigner for visual and quantitative analysis of histological datasets. HistoLens enables users to interrogate sets of digitally annotated whole slide images to efficiently characterize histological differences between disease and experimental groups. Users can dynamically visualize the distribution of 448 hand-engineered features quantifying color, texture, morphology, and distribution across microanatomic sub-compartments. Additionally, users can map differentially detected image features within the images by highlighting affected regions. We demonstrate the utility of HistoLens to identify hand-engineered features that correlate with pathognomonic renal glomerular characteristics distinguishing diabetic nephropathy and amyloid nephropathy from the histologically unremarkable glomeruli in minimal change disease. Additionally, we examine the use of HistoLens for glomerular feature discovery in the Tg26 mouse model of HIV-associated nephropathy. We identify numerous quantitative glomerular features distinguishing Tg26 transgenic mice from wild-type mice, corresponding to a progressive renal disease phenotype. Thus, we demonstrate an off-the-shelf and ready-to-use toolkit for quantitative renal pathology applications.


Asunto(s)
Ratones Transgénicos , Animales , Ratones , Glomérulos Renales/patología , Riñón/patología , Enfermedades Renales/patología , Modelos Animales de Enfermedad , Nefropatías Diabéticas/patología , Humanos , Procesamiento de Imagen Asistido por Computador/métodos
16.
Children (Basel) ; 11(7)2024 Jul 12.
Artículo en Inglés | MEDLINE | ID: mdl-39062294

RESUMEN

Child-to-parent violence is a form of family violence where the children are the aggressors. OBJECTIVE: This study first aimed to analyze the psychometric validity of the Child-to-Parent Violence Questionnaire (CPV-Q) among Ecuadorian adolescents. Second, the measurement invariance across the children's sex was examined. Finally, the prevalence of child-to-parent violence (CPV) was also determined. METHODS: A total of 2084 adolescents aged 12 to 18 years participated in this study. The participants were residents of two provinces in southern Ecuador. A higher percentage of participants were women. They lived mostly with their father and mother. The married marital status of the parents was the most frequently reported. Most of the fathers and mothers of the participants completed primary education. The sampling design was probabilistic, with proportional allocation by age and quotas according to the number of inhabitants per province. The sample size was determined by using a finite population formula. All the participants were randomly selected. The CPV-Q was used to assess child-to-parent violence. The items were adapted linguistically and tailored to the Ecuadorian context. RESULTS: The questionnaire demonstrated excellent model fit and adequate reliability. Full measurement invariance was held for all scales except for the reasons subscale pertaining to fathers. Statistically significant differences were observed with respect to the sex of the aggressor, with control/domain behaviors toward both parents and psychological violence toward the mother being more frequent among daughters than sons. Similarly, reactive reasons were more frequent among daughters than sons. CONCLUSION: This study provides significant psychometric evidence on the CPV-Q in Ecuadorian adolescents along with data on the prevalence of violence against parents.

17.
J Chem Ecol ; 2024 Jun 29.
Artículo en Inglés | MEDLINE | ID: mdl-38949747

RESUMEN

Plant responses to damage by insectivorous herbivores are well-documented in mature leaves. The resulting herbivore-induced plant volatiles (HIPVs) protect the plant by attracting carnivorous arthropods and even some insectivorous vertebrates, to parasitize or consume the plant invaders. However, very little is known about plant production of HIPVs in developing buds, particularly when herbivorous insects are too small to be considered a prey item. It is additionally unclear whether plants respond differently to generalist and specialist chewing insects that overlap in distribution. Therefore, we compared HIPV production of Downy oak (Quercus pubescens Willd.) buds infested with freshly hatched caterpillars of Tortrix viridana (specialist) and Operophtera brumata (generalist), against uninfested buds. Of the compounds identified in both years of the experiment, we found that (Z)-hex-3-enyl acetate, (E)-ß-ocimene, acetophenone, linalool, (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT), methyl salicylate, α-copaene, α-humulene, (E)-caryophyllene, and (E,E)-α-farnesene appeared to be higher in infested buds compared to controls. We found no difference in HIPV production between the specialist and the generalist herbivores. Production of HIPVs was also associated with leaf damage, with higher HIPV production in more severely attacked buds. Thus, our study shows that oak trees already start responding to insect herbivory before leaves are developed, by producing compounds similar to those found in damaged mature leaves. Future work should focus on how Downy oak may benefit from initiating alarm cues at a time when carnivorous arthropods and insectivorous vertebrates are unable to use herbivorous insects as host or food.

18.
Structure ; 2024 Jul 12.
Artículo en Inglés | MEDLINE | ID: mdl-39025067

RESUMEN

Many membrane transporters share the LeuT fold-two five-helix repeats inverted across the membrane plane. Despite hundreds of structures, whether distinct conformational mechanisms are supported by the LeuT fold has not been systematically determined. After annotating published LeuT-fold structures, we analyzed distance difference matrices (DDMs) for nine proteins with multiple available conformations. We identified rigid bodies and relative movements of transmembrane helices (TMs) during distinct steps of the transport cycle. In all transporters, the bundle (first two TMs of each repeat) rotates relative to the hash (third and fourth TMs). Motions of the arms (fifth TM) to close or open the intracellular and outer vestibules are common, as is a TM1a swing, with notable variations in the opening-closing motions of the outer vestibule. Our analyses suggest that LeuT-fold transporters layer distinct motions on a common bundle-hash rock and demonstrate that systematic analyses can provide new insights into large structural datasets.

19.
Sci Adv ; 10(25): eadn4192, 2024 Jun 21.
Artículo en Inglés | MEDLINE | ID: mdl-38896606

RESUMEN

The shorelines of Titan's hydrocarbon seas trace flooded erosional landforms such as river valleys; however, it is unclear whether coastal erosion has subsequently altered these shorelines. Spacecraft observations and theoretical models suggest that wind may cause waves to form on Titan's seas, potentially driving coastal erosion, but the observational evidence of waves is indirect, and the processes affecting shoreline evolution on Titan remain unknown. No widely accepted framework exists for using shoreline morphology to quantitatively discern coastal erosion mechanisms, even on Earth, where the dominant mechanisms are known. We combine landscape evolution models with measurements of shoreline shape on Earth to characterize how different coastal erosion mechanisms affect shoreline morphology. Applying this framework to Titan, we find that the shorelines of Titan's seas are most consistent with flooded landscapes that subsequently have been eroded by waves, rather than a uniform erosional process or no coastal erosion, particularly if wave growth saturates at fetch lengths of tens of kilometers.

20.
J Neurosci ; 44(29)2024 Jul 17.
Artículo en Inglés | MEDLINE | ID: mdl-38858080

RESUMEN

The resurgent sodium current (INaR) activates on membrane repolarization, such as during the downstroke of neuronal action potentials. Due to its unique activation properties, INaR is thought to drive high rates of repetitive neuronal firing. However, INaR is often studied in combination with the persistent or noninactivating portion of sodium currents (INaP). We used dynamic clamp to test how INaR and INaP individually affect repetitive firing in adult cerebellar Purkinje neurons from male and female mice. We learned INaR does not scale repetitive firing rates due to its rapid decay at subthreshold voltages and that subthreshold INaP is critical in regulating neuronal firing rate. Adjustments to the voltage-gated sodium conductance model used in these studies revealed INaP and INaR can be inversely scaled by adjusting occupancy in the slow-inactivated kinetic state. Together with additional dynamic clamp experiments, these data suggest the regulation of sodium channel slow inactivation can fine-tune INaP and Purkinje neuron repetitive firing rates.


Asunto(s)
Potenciales de Acción , Células de Purkinje , Canales de Sodio , Animales , Ratones , Femenino , Masculino , Potenciales de Acción/fisiología , Células de Purkinje/fisiología , Canales de Sodio/fisiología , Canales de Sodio/metabolismo , Sodio/metabolismo , Ratones Endogámicos C57BL , Técnicas de Placa-Clamp , Modelos Neurológicos
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