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1.
Adv Sci (Weinh) ; : e2405622, 2024 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-38961635

RESUMO

The stability of hybrid organic-inorganic halide perovskite semiconductors remains a significant obstacle to their application in photovoltaics. To this end, the use of low-dimensional (LD) perovskites, which incorporate hydrophobic organic moieties, provides an effective strategy to improve their stability, yet often at the expense of their performance. To address this limitation, supramolecular engineering of noncovalent interactions between organic and inorganic components has shown potential by relying on hydrogen bonding and conventional van der Waals interactions. Here, the capacity to access novel LD perovskite structures that uniquely assemble through unorthodox S-mediated interactions is explored by incorporating benzothiadiazole-based moieties. The formation of S-mediated LD structures is demonstrated, including one-dimensional (1D) and layered two-dimensional (2D) perovskite phases assembled via chalcogen bonding and S-π interactions, through a combination of techniques, such as single crystal and thin film X-ray diffraction, as well as solid-state NMR spectroscopy, complemented by molecular dynamics simulations, density functional theory calculations, and optoelectronic characterization, revealing superior conductivities of S-mediated LD perovskites. The resulting materials are applied in n-i-p and p-i-n perovskite solar cells, demonstrating enhancements in performance and operational stability that reveal a versatile supramolecular strategy in photovoltaics.

2.
Artigo em Inglês | MEDLINE | ID: mdl-38923340

RESUMO

Diagnosis of asthma can be confirmed based on variability in peak expiratory flow (PEF) or changes in forced expiratory volume in 1 s (FEV1) measured with spirometry. Our aim was to use methacholine challenge as a model of induced airway obstruction to assess how well relative changes in PEF reflect airway obstruction in comparison to relative changes in FEV1. We retrospectively studied 878 patients who completed a methacholine challenge test. To assess congruency along with differences between relative changes in FEV1 and PEF during airway obstruction, a regression analysis was performed, and a Bland & Altman plot was constructed. ROC analysis, sensitivity, specificity, positive and negative predictive values and κ-coefficient were used to analyze how decrease in PEF predicts decrease of 10% or 15% in FEV1. The relative change in PEF was on average less than the relative change in FEV1. In the ROC analysis areas under the curve were 0.844 and 0.893 for PEF decrease to predict a 10% and 15% decrease in FEV1, respectively. The agreement between changes in PEF and FEV1 varied from fair to moderate. Airway obstruction detected by change in PEF was false in about 40% of cases when compared to change in FEV1. Change in PEF is not a very accurate measure of airway obstruction when compared to change in FEV1. Replacing peak flow metre with a handheld spirometer might improve diagnostic accuracy of home monitoring in asthma.

3.
J Dairy Sci ; 2024 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-38908694

RESUMO

Selective treatment of clinical mastitis (STCM) potentially reduces antimicrobial use without negative implications on cow's milk production or health. However, this approach comes with additional costs. The aim of this study was to evaluate the net cash impact (NCI) of implementing STCM compared with blanket treatment of clinical mastitis (BTCM) under different diagnostic-test turnaround times (24 h, 14 h, and 8 h) using a stochastic partial budget analysis with Monte Carlo simulation. The target population was European commercial dairy herds; therefore, the model inputs were primarily from European sources. Additionally, variables associated with dairy management programs were obtained from USDA sources, worldwide multisite clinical trials, and expert opinion. The output was calculated by subtracting the cost of STCM from the cost of BTCM and it represented the expected NCI if a herd switched from BTCM to STCM. Depending on the time-to-treatment efficiency and diagnostic-test turnaround time, the expected mean NCI, assuming that STCM has no impact on the cow's future health or production, ranged from +€8.7 to +€12.4 per case with 72.4% to 84.8% of the iterations being ≥ €0. Moreover, using the numerically favorable health and production effects of STCM reported in the literature, the expected mean NCI ranged from +€44.5 to +€48.1 per case with 93.6% to 95.4% of the iterations being ≥ €0. The variables with the greatest contribution to NCI variance were proportion of gram-positive cases (39.2% of the variance) and days out of the tank for treated cows (22.0%). However, if future cow's health and production were accounted for, culling risk (24.6%), recurrence risk (19.4%), and milk yield (10.6%) would have the greatest contribution to NCI. The sensitivity analysis indicated that farms with high clinical mastitis incidence, low proportion of gram-positive cases, large number of days out of the tank for treated cows, higher milking frequency or using automatic milking systems, not using the highest priced diagnostic tests, and having high antimicrobial treatment costs are the best candidates for STCM. Improving time-to-treatment efficiency, for example, by using a rapid diagnostic test, leads to a favorable NCI, while high daily milk yield and milk price enhances the NCI in already positive scenarios. Finally, the cash flow entirely depends on future cow's health and milk yield. In conclusion, results indicate that overall, STCM is a practice that positively impacts the NCI of many herds.

4.
Crit Care Nurs Q ; 47(3): 175-183, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38860947

RESUMO

Innovations in oncology have expanded treatment eligibility, leading to a rise in cancer patients requiring critical care. This necessitates that all critical care clinicians possess a fundamental knowledge of prevalent oncological conditions and identify emergent scenarios requiring immediate action. This article will explore key oncological complications and their management approaches.


Assuntos
Emergências , Neoplasias , Humanos , Neoplasias/terapia , Cuidados Críticos , Enfermagem de Cuidados Críticos
5.
Food Chem ; 455: 139958, 2024 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-38850992

RESUMO

The feasibility of Near Infrared Spectroscopy was assessed for aging traceability of steaks of Angus beef (Biceps femoris) individually vacuum-packaged, as well as for the prediction of the refrigeration storage time (0, 7, and 14 days). For this purpose, a total of 288 steaks homogeneously distributed among the sampling times were used. The model developed by Partial Least Squares-Discriminant Analysis offered high discrimination ability between aged beef vs. non-aged. The accuracy after external validation exceeded 90%. Regarding the predictive capacity of the storage time, it was greater on the set of aged samples, in which the accuracy achieved values higher than 96%, while the accuracy decreased to 75% for the non-aged samples. Results obtained support the ability of NIRS technology to be considered in any digital transformation strategy for traceability across the meat supply chain.

6.
Cell ; 187(11): 2735-2745.e12, 2024 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-38723628

RESUMO

Hepatitis B virus (HBV) is a small double-stranded DNA virus that chronically infects 296 million people. Over half of its compact genome encodes proteins in two overlapping reading frames, and during evolution, multiple selective pressures can act on shared nucleotides. This study combines an RNA-based HBV cell culture system with deep mutational scanning (DMS) to uncouple cis- and trans-acting sequence requirements in the HBV genome. The results support a leaky ribosome scanning model for polymerase translation, provide a fitness map of the HBV polymerase at single-nucleotide resolution, and identify conserved prolines adjacent to the HBV polymerase termination codon that stall ribosomes. Further experiments indicated that stalled ribosomes tether the nascent polymerase to its template RNA, ensuring cis-preferential RNA packaging and reverse transcription of the HBV genome.


Assuntos
Vírus da Hepatite B , Transcrição Reversa , Humanos , Genoma Viral/genética , Vírus da Hepatite B/genética , Mutação , Ribossomos/metabolismo , RNA Viral/genética , RNA Viral/metabolismo , Linhagem Celular
7.
Mol Cell ; 84(10): 1995-2005.e7, 2024 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-38614096

RESUMO

Cytokines regulate immune responses by binding to cell surface receptors, including the common subunit beta (ßc), which mediates signaling for GM-CSF, IL-3, and IL-5. Despite known roles in inflammation, the structural basis of IL-5 receptor activation remains unclear. We present the cryo-EM structure of the human IL-5 ternary receptor complex, revealing architectural principles for IL-5, GM-CSF, and IL-3. In mammalian cell culture, single-molecule imaging confirms hexameric IL-5 complex formation on cell surfaces. Engineered chimeric receptors show that IL-5 signaling, as well as IL-3 and GM-CSF, can occur through receptor heterodimerization, obviating the need for higher-order assemblies of ßc dimers. These findings provide insights into IL-5 and ßc receptor family signaling mechanisms, aiding in the development of therapies for diseases involving deranged ßc signaling.


Assuntos
Microscopia Crioeletrônica , Fator Estimulador de Colônias de Granulócitos e Macrófagos , Interleucina-3 , Multimerização Proteica , Transdução de Sinais , Humanos , Fator Estimulador de Colônias de Granulócitos e Macrófagos/metabolismo , Fator Estimulador de Colônias de Granulócitos e Macrófagos/química , Fator Estimulador de Colônias de Granulócitos e Macrófagos/genética , Interleucina-3/metabolismo , Interleucina-3/química , Interleucina-3/genética , Células HEK293 , Ligação Proteica , Modelos Moleculares , Interleucina-5/metabolismo , Subunidade beta Comum dos Receptores de Citocinas/metabolismo , Subunidade beta Comum dos Receptores de Citocinas/genética , Subunidade beta Comum dos Receptores de Citocinas/química , Imagem Individual de Molécula , Relação Estrutura-Atividade , Sítios de Ligação , Receptores de Interleucina-5/metabolismo , Receptores de Interleucina-5/genética , Receptores de Interleucina-5/química
8.
Polymers (Basel) ; 16(8)2024 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-38675008

RESUMO

The aim of this research is to investigate basalt as a natural mineral-based fibre together with a vitrimeric resin as a sustainable alternative to standard composite materials. Vitrimers combine the properties of thermoset and thermoplastic polymers, enabling the repair of specimens and hence prolonging the lifetime of the composite material. The micro-mechanical characteristics between the basalt fibres and the vitrimer resin are reported and shown to match those of a standard Skyflex K51 epoxy resin. Discontinuous (4 mm) basalt fibres were employed to produce aligned discontinuous fibre-reinforced composites (ADFRCs) using the high-performance discontinuous fibre (HiPerDiF) technology. The mechanical characteristics of the laminates were investigated through tensile testing and the fracture zones were analysed under a scanning electron microscope. By normalising the results by their respective fibre volume fraction, it was discovered that the vitrimer-basalt ADFRCs exhibited, on average, a 4% higher strength and a 25% higher stiffness compared to their basalt epoxy counterparts. The repair potential of the vitrimer ADFRC specimens was explored during low-temperature compression repair. Two approaches were tested using double-sided local- and full-patch repair. Both successfully recovered a significant amount of their prime strength. In conclusion, the potential of the sustainable vitrimer-basalt composite is shown by its competitive mechanical performance. Combining this with the manufacturing flexibility, repair potential, and recyclability of the material, the vitrimer-basalt composite seems to be a competitive alternative to standard glass epoxies.

9.
Sci Total Environ ; 929: 172531, 2024 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-38636873

RESUMO

The lack of extreme water level fluctuations in managed, non-peat forming wetland ecosystems can result in decreased productivity through the loss of heterogeneity of these ecosystems. Stochastic disruption, such as a water level drawdown, can effectively reverse this effect and return the wetland to a more productive state, associated with higher biodiversity through new vegetation development. Yet, aside from the effect on vegetation dynamics, little is known about longer-term effects (30 years) of a water level drawdown, hereafter referred to as legacy effects, and how this may impact future water level drawdowns. Here, we aim to unravel the legacy effects of a water level drawdown, stand alone and along a water level gradient, on seed bank properties and nutrient availability in a eutrophic clay wetland. To identify these, we studied the hydrologically managed nature reserve Oostvaardersplassen in the Netherlands. Here, one section was subjected to a multi-year water level drawdown and another section was kept inundated. We determined seed bank properties in both areas, spatially and along a soil elevation gradient (20 cm). Nutrient availability was measured by taking sediment samples along the water level gradient and through experimental manipulation of the water level in an indoor mesocosm experiment. Germination was higher in locations with a water level drawdown history, especially at relatively high elevations. Additionally, the proportion of pioneer species in the seed bank was higher in the water level drawdown area. Overall, nutrient concentrations were higher compared to other aquatic systems. Nutrient availability was higher in the inundated area and did not respond to the water level gradient. We conclude that 30 years after an induced water level drawdown there is no depletion of nutrients, while we still observe a legacy effect in the number of viable seeds in the seed bank.

10.
Data Brief ; 54: 110329, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38550229

RESUMO

This dataset provides a comprehensive compilation of Ground Penetrating Radar (GPR) surveys across 125 utility surveying activities in the Netherlands. The dataset details the specific use of GPR in each authentic real-life utility surveying activity, whether employed independently or as a complementary tool alongside existing surveying methods, with or without post-processing. The dataset includes 959 radargrams, ground-truth information obtained from trial trenches, and an inventory of construction, geophysical, infrastructural, and technical features. The GPR utilised in all activities is an air-coupled radar with a 500 MHz frequency antenna, a GNSS RTK positioning system, and a measuring wheel encoder. This ground-truth dataset provides researchers with a valuable resource to further assess the practical efficacy of GPR as a utility surveying method, refine radargram processing algorithms and techniques, and explore the possibilities of predictive modelling.

11.
Crit Care Explor ; 6(2): e1047, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38343442

RESUMO

BACKGROUND: This case series explores the management of respiratory failure in patients with large anterior tracheal thyroid tumors where tracheostomy is not an option. To our knowledge, this study is the first to address the challenges associated with caring for such patients. CASE SUMMARY: We present the clinical courses of four intubated adults with advanced thyroid cancer and complex airway issues that preclude surgical tracheostomy. Interventions included custom airway stents, long-term intubation, and oncological therapies. Ethical quandaries around patient autonomy and capacity emerged, exacerbated by the absence of viable exit strategies for prolonged intubation, notably the performance of a tracheostomy, causing emotional distress in patients, families, and staff. CONCLUSIONS: This study showcases the multifaceted challenges in medical, ethical, and emotional domains associated with managing intubated patients with complex disease precluding tracheotomies. We advocate for a nuanced, multidisciplinary, and personalized approach to confront unique issues in airway management, ethical considerations, and disposition.

12.
J Am Assoc Nurse Pract ; 36(1): 73-76, 2024 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-37471564

RESUMO

ABSTRACT: Brain natriuretic peptide (BNP) is a well-established biomarker for heart failure (HF). However, its diagnostic utility can be limited in patients with comorbidities that independently elevate serum BNP levels, including chronic renal failure and sepsis. We describe a rare occurrence of significantly elevated serum BNP levels in a patient with metastatic urothelial cancer without HF or obvious signs of sepsis. The report highlights the need for considering alternative causes for increased serum BNP levels, especially in the presence of malignancy.


Assuntos
Insuficiência Cardíaca , Neoplasias , Sepse , Humanos , Biomarcadores , Peptídeo Natriurético Encefálico
13.
Ann Surg ; 279(1): 147-153, 2024 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-37800338

RESUMO

OBJECTIVE: This study compared outcomes in patients with solid tumor treated for pericardial effusion with surgical drainage versus interventional radiology (IR) percutaneous drainage and compared incidence of paradoxical hemodynamic instability (PHI) between cohorts. BACKGROUND: Patients with advanced-stage solid malignancies may develop large pericardial effusions requiring intervention. PHI is a fatal and underreported complication that occurs following pericardial effusion drainage. METHODS: Clinical characteristics and outcomes were compared between patients with solid tumors who underwent s urgical drainage or IR percutaneous drainage for pericardial effusion from 2010 to 2020. RESULTS: Among 447 patients, 243 were treated with surgical drainage, of which 27 (11%) developed PHI, compared with 7 of 204 patients (3%) who were treated with IR percutaneous drainage ( P =0.002); overall incidence of PHI decreased during the study period. Rates of reintervention (30-day: 1% vs 4%; 90-day: 4% vs 6%, P =0.7) and mortality (30-day: 21% vs 17%, P =0.3; 90-day: 39% vs 37%, P =0.7) were not different between patients treated with surgical drainage and IR percutaneous drainage. For both interventions, OS was shorter among patients with PHI than among patients without PHI (surgical drainage, median [95% confidence interval] OS, 0.89 mo [0.33-2.1] vs 6.5 mo [5.0-8.9], P <0.001; IR percutaneous drainage, 3.7 mo [0.23-6.8] vs 5.0 mo [4.0-8.1], P =0.044). CONCLUSIONS: With a coordinated multidisciplinary approach focusing on prompt clinical and echocardiographic evaluation, triage with bias toward IR percutaneous drainage than surgical drainage and postintervention intensive care resulted in lower incidence of PHI and improved outcomes.


Assuntos
Neoplasias , Derrame Pericárdico , Procedimentos Cirúrgicos Torácicos , Doenças Vasculares , Humanos , Derrame Pericárdico/etiologia , Derrame Pericárdico/cirurgia , Neoplasias/complicações , Doenças Vasculares/etiologia , Drenagem/métodos , Estudos Retrospectivos , Hemodinâmica
14.
Meat Sci ; 206: 109348, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37778130

RESUMO

The potential of Near Infrared Spectroscopy (NIRS) was assessed for storage temperature discrimination (4 °C ± 2 vs. 20 °C ± 2) and for the prediction of the length of time that sliced Duroc dry-cured ham was in storage, considering the following packaging types; vacuum (n = 133) and modified atmosphere (MAP) (n = 133), without opening the package. The models, obtained by means of Partial least squares-discriminant analysis, indicated successful classification of the product according to storage temperature after validation (accuracy values of 100.00% in vacuum and between 92.00 and 100% in MAP). Furthermore, good accuracy was obtained for the assignments into storage times, with values comprised between 92.31% and 100.00% for samples under vacuum and between 91.00% and 97.00% for those under MAP, in both cases after validation. Thus, NIRS technology could help to support the preservation temperature traceability and the stocks of sliced dry-cured hams.


Assuntos
Produtos da Carne , Carne de Porco , Temperatura , Embalagem de Alimentos/métodos , Carne de Porco/análise , Espectroscopia de Luz Próxima ao Infravermelho , Produtos da Carne/análise
15.
Artigo em Inglês | MEDLINE | ID: mdl-37646585

RESUMO

ABSTRACT: Implementation of a comprehensive point-of-care ultrasound (POCUS) program for nurse practitioners (NPs) and physician assistants (PAs) in an intensive care unit (ICU) setting improves their diagnostic and therapeutic skills and enhances patient care. Overcoming staffing, IT infrastructure, and administrative challenges has allowed our critical care medicine service to develop a successful program that empowers NPs and PAs and boosts their professional growth. Our POCUS program underscores the necessity of institutional support, dedicated mentorship, collaboration with qualified faculty, and creation and maintenance of a curriculum that adheres to accepted national guidelines. Insights gained from our experiences can serve as a valuable resource for institutions aiming to develop their own POCUS programs.

16.
Chem Sci ; 14(32): 8607-8614, 2023 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-37592977

RESUMO

Precise synthesis of graphene nanoribbons (GNRs) is of great interest to chemists and materials scientists because of their unique opto-electronic properties and potential applications in carbon-based nanoelectronics and spintronics. In addition to the tunable edge structure and width, introducing curvature in GNRs is a powerful structural feature for their chemi-physical property modification. Here, we report an efficient solution synthesis of the first pyrene-based GNR (PyGNR) with curved geometry via one-pot K-region oxidation and Scholl cyclization of its corresponding well-soluble tetrahydropyrene-based polyphenylene precursor. The efficient A2B2-type Suzuki polymerization and subsequent Scholl reaction furnishes up to ∼35 nm long curved GNRs bearing cove- and armchair-edges. The construction of model compound 1, as a cutout of PyGNR, from a tetrahydropyrene-based oligophenylene precursor proves the concept and efficiency of the one-pot K-region oxidation and Scholl cyclization, which is clearly revealed by single crystal X-ray diffraction analysis. The structure and optical properties of PyGNR are investigated by Raman, FT-IR, solid-state NMR, STM and UV-Vis analysis with the support of DFT calculations. PyGNR exhibits a narrow optical bandgap of ∼1.4 eV derived from a Tauc plot, qualifying as a low-bandgap GNR. Moreover, THz spectroscopy on PyGNR estimates its macroscopic charge mobility µ as ∼3.6 cm2 V-1 s-1, outperforming several other curved GNRs reported via conventional Scholl reaction.

17.
Integr Org Biol ; 5(1): obad025, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37521144

RESUMO

Evidence suggests that hurricanes can influence the evolution of organisms, with phenotypic traits involved in adhesion, such as the toepads of arboreal lizards, being particularly susceptible to natural selection imposed by hurricanes. To investigate this idea, we quantified trait variation before and after Hurricanes Irma and Maria (2017) in forest and urban populations of the Puerto Rican lizard Anolis cristatellus. We found that the hurricanes affected toe morphology differently between forest and urban sites. In particular, toepads of the forefeet were longer and narrower in forest, but wider in urban populations, compared to pre-hurricane measures. Toepads of the hind feet were larger in area following the hurricanes. Fore and rear toes increased in length following the hurricane. There were no changes in the number of lamellae scales or lamellae spacing, but lamellae 6-11 of the forefeet shifted proximally following the hurricane. We also measured clinging performance and toe shape. We found that toepad area and toe lengths were stronger predictors of adhesive forces than toepad shape. Our results highlight an interaction between urbanization and hurricanes, demonstrating the importance to consider how urban species will respond to extreme weather events. Additionally, our different results for fore and rear feet highlight the importance of evaluating both of these traits when measuring the morphological response to hurricanes in arboreal lizards.


La evidencia sugiere que los huracanes pueden influir en la evolución de los organismos, rasgos fenotípicos como las almohadillas distales de los lagartos arbóreos, son particularmente susceptibles a la selección natural impuesta por los huracanes. Para investigar esta idea, cuantificamos la variación de las almohadillas distales antes y después de los huracanes Irma y María (2017) en poblaciones de bosques y urbanas de las lagartijas puertorriqueña Anolis cristatellus. Encontramos que los cambios morfológicos luego de los huracanes variaron entre las poblaciones de bosque y urbanas. Para las poblaciones de bosque, las almohadillas de las patas delanteras eran más largas y estrechas luego de las tormentas. Por el contrario, las almohadillas delanteras de las poblaciones urbanas fueron más anchas luego de los huracanes. Las almohadillas de los pies traseros tenían un área más grande en todas las poblaciones luego de los huracanes. Los dedos delanteros y traseros aumentaron de longitud después del huracán. No hubo cambios en el número de escamas en las almohadillas distales ni en el ancho de estas escamas, pero las escamas 6­11 de las patas delanteras se desplazaron proximalmente después del huracán. También medimos las fuerzas adhesivas producida por las almohadillas distales para contrastar con la morfología de los dedos. Encontramos que el área de las almohadillas distales y la longitud de los dedos fueron los predictores más fuertes de las fuerzas adhesivas. Nuestros resultados destacan una interacción entre la urbanización y los huracanes, lo que demuestra la importancia de considerar cómo responderán las especies urbanas a los eventos climáticos extremos. Además, nuestros diferentes resultados para las patas delanteras y traseras resaltan la importancia de evaluar ambos rasgos al medir la respuesta morfológica a los huracanes en lagartijas arbóreos.

18.
J Am Assoc Nurse Pract ; 35(7): 397-399, 2023 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-37390460
19.
Cell Rep ; 42(6): 112657, 2023 06 27.
Artigo em Inglês | MEDLINE | ID: mdl-37339051

RESUMO

Interleukin-21 (IL-21) plays a critical role in generating immunological memory by promoting the germinal center reaction, yet clinical use of IL-21 remains challenging because of its pleiotropy and association with autoimmune disease. To better understand the structural basis of IL-21 signaling, we determine the structure of the IL-21-IL-21R-γc ternary signaling complex by X-ray crystallography and a structure of a dimer of trimeric complexes using cryo-electron microscopy. Guided by the structure, we design analogs of IL-21 by introducing substitutions to the IL-21-γc interface. These IL-21 analogs act as partial agonists that modulate downstream activation of pS6, pSTAT3, and pSTAT1. These analogs exhibit differential activity on T and B cell subsets and modulate antibody production in human tonsil organoids. These results clarify the structural basis of IL-21 signaling and offer a potential strategy for tunable manipulation of humoral immunity.


Assuntos
Centro Germinativo , Interleucinas , Humanos , Microscopia Crioeletrônica , Cristalografia por Raios X , Interleucina-2
20.
Glob Chang Biol ; 29(9): 2522-2535, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-36843188

RESUMO

Climate change projections indicate more frequent and severe tropical marine heatwaves (MHWs) and accompanying hypoxia year-round. However, most studies have focused on peak summer conditions under the assumption that annual maximum temperatures will induce the greatest physiological consequences. This study challenges this idea by characterizing seasonal MHWs (i.e., mean, maximum, and cumulative intensities, durations, heating rates, and mean annual occurrence) and comparing metabolic traits (i.e., standard metabolic rate (SMR), Q10 of SMR, maximum metabolic rate (MMR), aerobic scope, and critical oxygen tension (Pcrit )) of winter- and summer-acclimatized convict tang (Acanthurus triostegus) to the combined effects of MHWs and hypoxia. Fish were exposed to one of six MHW treatments with seasonally varying maximum intensities (winter: 24.5, 26.5, 28.5°C; summer: 28.5, 30.5, 32.5°C), representing past and future MHWs under IPCC projections (i.e., +0, +2, +4°C). Surprisingly, MHW characteristics did not significantly differ between seasons, yet SMR was more sensitive to winter MHWs (mean Q10 = 2.92) than summer MHWs (mean Q10 = 1.81), despite higher absolute summer temperatures. Concurrently, MMR increased similarly among winter +2 and +4°C treatments (i.e., 26.5, 28.5°C) and all summer MHW treatments, suggesting a ceiling for maximal MMR increase. Aerobic scope did not significantly differ between seasons nor among MHW treatments. While mean Pcrit did not significantly vary between seasons, warming of +4°C during winter (i.e., 28.5°C) significantly increased Pcrit relative to the winter control group. Contrary to the idea of increased sensitivity to MHWs during the warmest time of year, our results reveal heightened sensitivity to the deleterious effects of winter MHWs, and that seasonal acclimatization to warmer summer conditions may bolster metabolic resilience to warming and hypoxia. Consequently, physiological sensitivity to MHWs and hypoxia may extend across larger parts of the year than previously expected, emphasizing the importance of evaluating climate change impacts during cooler seasons when essential fitness-related traits such as reproduction occur in many species.


Assuntos
Recifes de Corais , Peixes , Animais , Estações do Ano , Temperatura Alta , Temperatura , Aclimatação , Hipóxia
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