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1.
Intern Emerg Med ; 2024 Sep 06.
Artículo en Inglés | MEDLINE | ID: mdl-39240412

RESUMEN

Ultrasound has become an increasingly valuable tool for the assessment of body composition, offering several applications and indications in clinical practice. Ultrasound allows bedside evaluation of muscle mass, fat compartments, and extravascular water, providing a cost-effective, portable, and accessible alternative to traditional methods, such as Dual-energy X-ray Absorptiometry (DEXA), Bioelectrical Impedance Analysis (BIA), Computed Tomography (CT), and Magnetic Resonance Imaging (MRI). It is particularly useful in evaluating conditions, such as malnutrition, sarcopenia, and sarcopenic obesity, which require poor muscle mass to establish a diagnosis. The potential uses of ultrasound in body composition assessment include measurement of muscle thickness, cross-sectional area, pennation angle, and echo-intensity, which are indicative of muscle health. Additionally, ultrasound can be used to evaluate various fat compartments, including visceral, subcutaneous, and ectopic fat, which are important for understanding metabolic health and cardiovascular risk. However, the widespread adoption of ultrasound is challenged by the lack of standardized measurements and the absence of ultrasound measures in the validated diagnostic criteria. This article reviews the current applications of ultrasound in body composition assessment, highlighting the recent advancements and the correlation between ultrasound parameters and clinical outcomes. It discusses the advantages of ultrasound while also addressing its limitations, such as the need for standardized protocols and cut-off points. By providing a comprehensive update based on recent publications, this article aims to enhance the clinical utility of ultrasound in assessing and monitoring body composition and pave the way for future research in this field.

2.
J Mol Model ; 30(10): 332, 2024 Sep 14.
Artículo en Inglés | MEDLINE | ID: mdl-39276242

RESUMEN

CONTEXT: The reaction force constant ( κ ), introduced by Professor Alejandro Toro-Labbé, plays a pivotal role in characterizing the reaction pathway by assessing the curvature of the potential energy profile along the intrinsic reaction coordinate. This study establishes a novel link between κ and the reactivity descriptors of conceptual density functional theory (c-DFT). Specifically, we derive expressions that relate the reaction force constant to nuclear softness and variations in chemical potential. Our findings indicate that regions of the reaction pathway where κ is negative match with significant electronic structure rearrangements, while positive κ regions match mostly with geometric rearrangements. This correlation between κ and c-DFT reactivity descriptors enhances our understanding of the underlying forces driving chemical reactions and offers new perspectives for analyzing reaction mechanisms. METHODS: The internal reaction path for the proton transfer in SNOH, chemical potential, and nuclear softness were computed using DFT with B3LYP exchange-correlation functional and 6-311++G(d,2p) basis set.

3.
Molecules ; 29(17)2024 Aug 24.
Artículo en Inglés | MEDLINE | ID: mdl-39274852

RESUMEN

The demand for novel tissue grafting and regenerative wound care biomaterials is growing as traditional options often fall short in biocompatibility, functional integration with human tissue, associated cost(s), and sustainability. Salmon aquaculture generates significant volumes of waste, offering a sustainable opportunity for biomaterial production, particularly in osteo-conduction/-induction, and de novo clinical/surgical bone regeneration. Henceforth, this study explores re-purposing salmon waste through a standardized pre-treatment process that minimizes the biological waste content, followed by a treatment stage to remove proteins, lipids, and other compounds, resulting in a mineral-rich substrate. Herein, we examined various methods-alkaline hydrolysis, calcination, and NaOH hydrolysis-to better identify and determine the most efficient and effective process for producing bio-functional nano-sized hydroxyapatite. Through comprehensive chemical, physical, and biological assessments, including Raman spectroscopy and X-ray diffraction, we also optimized the extraction process. Our modified and innovative alkaline hydrolysis-calcination method yielded salmon-derived hydroxyapatite with a highly crystalline structure, an optimal Ca/P ratio, and excellent biocompatibility. The attractive nano-scale cellular/tissular properties and favorable molecular characteristics, particularly well-suited for bone repair, are comparable to or even surpass those of synthetic, human, bovine, and porcine hydroxyapatite, positioning it as a promising candidate for use in tissue engineering, wound healing, and regenerative medicine indications.


Asunto(s)
Huesos , Durapatita , Salmón , Animales , Durapatita/química , Huesos/química , Materiales Biocompatibles/química , Hidrólisis , Humanos , Regeneración Ósea , Difracción de Rayos X , Espectrometría Raman
4.
Antioxidants (Basel) ; 13(8)2024 Aug 03.
Artículo en Inglés | MEDLINE | ID: mdl-39199193

RESUMEN

Stroke is a leading cause of death worldwide, yet current therapeutic strategies remain limited. Among the neuropathological events underlying this disease are multiple cell death signaling cascades, including autophagy. Recent interest has focused on developing agents that target molecules involved in autophagy to modulate this process under pathological conditions. This study aimed to analyze the role of autophagy in cell death induced by an in vitro ischemia-reperfusion (IR) model and to determine whether nitrones, known for their neuroprotective and antioxidant effects, could modulate this process. We focused on key proteins involved in different phases of autophagy: HIF-1α, BNIP3, and BECN1 for induction and nucleation, LC3 for elongation, and p62 for degradation. Our findings confirmed that the IR model promotes autophagy, initially via HIF-1α activation. Additionally, the neuroprotective effect of three of the selected synthetic nitrones (quinolylnitrones QN6 and QN23, and homo-bis-nitrone HBN6) partially derives from their antiautophagic properties, demonstrated by a downregulation of the expression of molecular markers involved in various phases of autophagy. In contrast, the neuroprotective power of cholesteronitrone ChN2 seems to derive from its promoting effects on the initial phases of autophagy, which could potentially help inhibit other forms of cell death. These results underscore the importance of autophagy modulation in neuroprotection, highlighting the potential of inhibiting prodeath autophagy and promoting prosurvival autophagy as promising therapeutic approaches in treating ischemic stroke clinically.

5.
Curr Issues Mol Biol ; 46(8): 7812-7831, 2024 Jul 23.
Artículo en Inglés | MEDLINE | ID: mdl-39194680

RESUMEN

The intestinal microbiota and the human body are in a permanent interaction. There is a symbiotic relationship in which the microbiota plays a vitally important role in the performance of numerous functions, including digestion, metabolism, the development of lymphoid tissue, defensive functions, and other processes. It is a true metabolic organ essential for life and has potential involvement in various pathological states, including cancer and pathologies other than those of a digestive nature. A growing topic of great interest for its implications is the relationship between the microbiota and cancer. Dysbiosis plays a role in oncogenesis, tumor progression, and even the response to cancer treatment. The effect of the microbiota on tumor development goes beyond a local effect having a systemic effect. Another aspect of great interest regarding the intestinal microbiota is its relationship with drugs, modifying their activity. There is increasing evidence that the microbiota influences the therapeutic activity and side effects of antineoplastic drugs and also modulates the response of several tumors to antineoplastic therapy through immunological circuits. These data suggest the manipulation of the microbiota as a possible adjuvant to improve oncological treatment. Is it possible to manipulate the microbiota for therapeutic purposes?

6.
Artículo en Inglés | MEDLINE | ID: mdl-39033959

RESUMEN

BACKGROUND: Reverse total shoulder arthroplasty (rTSA) has proven to be an effective surgical procedure for irreparable rotator cuff tears, comminuted fractures of the proximal humerus, and shoulder arthroplasty revision surgeries. We know from the literature that the functional results are good in the short term, but not whether these results remain stable in the long term or, on the contrary, show deterioration in functionality. OBJECTIVE: This study aims to analyze the functionality, degree of satisfaction, complications, and prosthesis survival at different cut-off points in patients with complex proximal humerus fractures treated with rTSA, with a minimum postoperative follow-up of 7 years. MATERIAL AND METHODS: Analytical, longitudinal, and prospective observational study of a cohort of patients treated for a fracture of the proximal humerus with Prótesis Inversa de Hombro. Functional outcome was assessed using the Constant Score and the Constant adjusted for age and gender of the patients. Quality of life was measured using the University of California at Los Angeles Shoulder Assessment scale and the Disability of the Arm, Shoulder and Hand score scale. In addition, range of motion, pain, and radiologic variables of loosening, scapular notching, and tuberosity consolidation were assessed. RESULTS: Thirty-three patients were included with a mean postoperative follow-up of 8.3 years (range 7-12 years). There was a progressive and significant decrease in Constant Score at 5 and 7 years follow-up compared to the baseline assessment 2 years after surgery, although the effect size was not significant. The age- and sex-adjusted Constant as well as the University of California at Los Angeles Shoulder Assessment scale did not show statistically significant variations at follow-up. Both shoulder abduction and anterior shoulder flexion correlated well with the final Disability of the Arm, Shoulder and Hand score scale score. Radiologic variables did not influence any of the study outcome variables. CONCLUSION: The functionality and quality of life of patients with complex proximal humerus fractures treated with rTSA decreased significantly compared to the 2-year evaluation, although this change was not clinically relevant. Survival of rTSA was satisfactory in the medium to long term with a low complication rate.

7.
Soc Cogn Affect Neurosci ; 19(1)2024 Jul 13.
Artículo en Inglés | MEDLINE | ID: mdl-38918898

RESUMEN

Gaze direction and pupil dilation play a critical role in communication and social interaction due to their ability to redirect and capture our attention and their relevance for emotional information. The present study aimed to explore whether the pupil size and gaze direction of the speaker affect language comprehension. Participants listened to sentences that could be correct or contain a syntactic anomaly, while the static face of a speaker was manipulated in terms of gaze direction (direct, averted) and pupil size (mydriasis, miosis). Left anterior negativity (LAN) and P600 linguistic event-related potential components were observed in response to syntactic anomalies across all conditions. The speaker's gaze did not impact syntactic comprehension. However, the amplitude of the LAN component for mydriasis (dilated pupil) was larger than for miosis (constricted pupil) condition. Larger pupils are generally associated with care, trust, interest, and attention, which might facilitate syntactic processing at early automatic stages. The result also supports the permeable and context-dependent nature of syntax. Previous studies also support an automatic nature of syntax (fast and efficient), which combined with the permeability to relevant sources of communicative information, such as pupil size and emotions, is highly adaptive for language comprehension and social interaction.


Asunto(s)
Comprensión , Electroencefalografía , Potenciales Evocados , Pupila , Percepción del Habla , Humanos , Pupila/fisiología , Femenino , Masculino , Comprensión/fisiología , Adulto Joven , Potenciales Evocados/fisiología , Adulto , Percepción del Habla/fisiología , Electroencefalografía/métodos , Fijación Ocular/fisiología , Atención/fisiología , Miosis , Midriasis , Adolescente
8.
J Clin Ultrasound ; 52(8): 1029-1036, 2024 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-38867304

RESUMEN

PURPOSE: The gastrocnemius venous system presents different anatomical variants. There have been described four locations of myofascial trigger points (MTrPs) in this muscle. However, no studies have analyzed the coincidence between vessels and MTrPs present in the gastrocnemius. Therefore, the main objective was to study the anatomical variability of the venous system by ultrasound and its coincidence with the location of the MTrPs. METHODS: A total of 100 lower limbs were studied. The gastrocnemius vessels were analyzed one by one by sector (medial, central, and lateral), quantifying the number of vessels, their distribution, and the coincidence with MTrPs. RESULTS: All muscle heads showed at least one vessel per section. A large variability was observed, from one to eight vessels per muscle head, with the most frequent number being three in the gastrocnemius medialis and two in the gastrocnemius lateralis. In all cases, the location of the vessels coincided with the MTrPs. CONCLUSIONS: The proximal gastrocnemius venous pattern is very variable between subjects in number of vessels and distribution, which has made it impossible to define a "safe" approach window for invasive procedures without ultrasound guidance. The coincidence between the clinical location of MTrPs of the gastrocnemius and the presence of vessels is total.


Asunto(s)
Músculo Esquelético , Puntos Disparadores , Ultrasonografía , Humanos , Músculo Esquelético/diagnóstico por imagen , Músculo Esquelético/irrigación sanguínea , Masculino , Femenino , Adulto , Puntos Disparadores/diagnóstico por imagen , Puntos Disparadores/fisiopatología , Ultrasonografía/métodos , Síndromes del Dolor Miofascial/diagnóstico por imagen , Síndromes del Dolor Miofascial/fisiopatología , Adulto Joven , Persona de Mediana Edad
9.
J Clin Med ; 13(12)2024 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-38930039

RESUMEN

Objectives: The association between anti-Ro/SSA antibodies and the appearance of cardiac rhythm disorders in adults is discussed. We aim to study this relationship, together with active treatments and comorbidities, and its impact on daily clinical practice in adults with systemic autoimmune diseases (SADs). Methods: This cross-sectional single-center study was conducted in a tertiary hospital between January 2021 and March 2022. A sample of adult patients followed up in the SAD Unit with a diagnosis of a SAD and previously tested for anti-Ro/SSA and anti-La/SSB were recruited. All of them underwent a 12-lead electrocardiogram. Results: 167 patients were included. 90 (53.9%) were positive for anti-Ro60, 101 (60.5%) for anti-Ro52, and 45 (26.9%) for anti-La/SSB; 52 (31.3%) were triple-negative. 84% were women, and the mean age was 59 years (standard deviation 12.8). The most common SAD was primary Sjögren's syndrome (34.8%), followed by systemic lupus erythematosus (24.6%) and rheumatoid arthritis (22.8%). A statistically significant relationship was found between anti-Ro52 positivity and cardiac rhythm disorders (relative risk = 2.007 [1.197-3.366]), specifically QTc prolongation (relative risk = 4.248 [1.553-11.615]). Multivariate regressions showed a significant association, with diabetes mellitus being the most related comorbidity. The association between anti-Ro52 antibodies and atrioventricular conduction disorders was not significant. Conclusions: The presence of anti-Ro52 antibodies in adult patients with SADs is associated with an increased risk of QTc prolongation. Electrocardiographic screening of patients with SAD, anti-Ro52 antibodies, and other risk factors, like diabetes mellitus or QT-prolonging drugs, seems advisable. Those with baseline electrocardiogram abnormalities or additional risk factors should undergo electrocardiographic monitoring.

10.
ACS Pharmacol Transl Sci ; 7(5): 1310-1319, 2024 May 10.
Artículo en Inglés | MEDLINE | ID: mdl-38751643

RESUMEN

The value of connected devices and health apps with features such as adherence trackers, dosing reminders, and remote communication tools for users and healthcare providers has been assessed to support home-based subcutaneous administration. A comprehensive survey was conducted with 605 participants, including users and caregivers, from eight countries. Medical conditions encompassed ankylosing spondylitis, asthma, cerebral palsy, cluster headaches, Crohn's disease, hemophilia, lupus, migraine, multiple sclerosis, Parkinson's disease, plaque psoriasis, psoriatic arthritis, rheumatoid arthritis, spasticity, spondyloarthritis, and ulcerative colitis. Utilizing a maximum difference scaling methodology, the survey gauged participant preferences regarding specific attributes and features of connected drug delivery devices. Irrespective of demographic factors like age, gender, nationality, or the specific medical condition, the device's ability to verify a successful injection stood out as universally valued. The second and third most valued attributes pertained to temperature-related indicators or warnings. These features do not necessitate the use of a connected device and can be integrated into existing autoinjector platforms. The survey findings support the development of a universal adherence tool for at-home subcutaneous dosing, independent of a specific medical condition. This tool may be gradually improved with disease-specific features. Once established as a platform, manufacturers can launch any subcutaneous medication and later integrate real-world evidence for enhanced educational, treatment, and diagnostic capabilities. This approach is crucial for advancing connected adherence tools in decentralized healthcare, aligning with user and healthcare system needs while translating scientific innovation into practical solutions.

11.
J Orthop ; 56: 87-91, 2024 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-38800591

RESUMEN

Background: Limited evidence is available comparing the modified transtibial (MTT) and transportal (TP) techniques in anterior cruciate ligament (ACL) reconstruction and their impact on returning to sports participation. The objective was to analyze the outcomes after arthroscopic reconstruction of the ACL in recreational athletes with a 2-year postoperative follow-up, comparing the MTT and TP techniques, based on the method used to drill the femoral tunnel. Hypotesis: The rate of return to sport would be comparable regardless of the surgical technique used. Material and methods: A retrospective study was conducted with 66 patients who underwent arthroscopic monofascicular ACL reconstruction between September 2016 and March 2020. Patients aged between 16 and 50 years old, recreational athletes at Tegner levels 6 and 7, with a 2-year follow-up were included. Groups were established for comparative analysis (MTT vs TP) based on the method for drilling the femoral tunnel. The main outcome variable was the return to sport at the same level. Secondary variables included patient satisfaction evaluated with a visual analogue scale (VAS) and knee function according to the Lysholm scale. Results: At 2 years of postoperative follow-up, the return to sport rate was 30.3 % in the MTT group and 33.3 % in the TP group (p = 0.791). There were no significant differences between both groups in patient satisfaction (p = 0.664) and knee function (p = 0.113). Conclusion: Drilling the femoral tunnel with the MTT and TP techniques did not influence the rate of return to sport, patient satisfaction, and knee function in recreational athletes with 2 years of postoperative follow-up. Level of evidence: III.

12.
Orthop Traumatol Surg Res ; 110(5): 103876, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-38582225

RESUMEN

BACKGROUND: The influence of smoking on the risk of periprosthetic joint infection (PJI) remains unclear. The objective was to explore the impact of smoking on PJI after primary total knee (TKA) and hip (THA) arthroplasty. HYPOTHESIS: Current smoking patients should have an increased risk of PIJ compared with nonsmoking patients. PATIENTS AND METHODS: A prospective registry-based observational cohort study was performed. A total of 4591 patients who underwent primary TKA (3076 patients) or THA (1515) were included. According to the smoking status at the time of arthroplasty, patients were classified as nonsmokers (3031 patients), ex-smokers (688), and smokers (872). Multivariate analysis included smoking status, age, gender, education level, body mass index, American Society of Anesthesiologists class, diagnosis (osteoarthritis, rheumatism), diabetes, chronic obstructive pulmonary disease, perioperative blood transfusion, site of arthroplasty (knee, hip), length of operation, and length of stay. RESULTS: There were PJI after 59 (1.9%) TKA and 27 (1.8%) THA (p=0.840). There were PJI in 47 (1.6%) nonsmokers, 12 (1.7%) ex-smokers, and 17 (1.9%) smokers (p=0.413). There were wound complications (delayed wound healing and superficial wound infection) in 34 (0.7%) nonsmokers, 9 (1.3%) in ex-smokers, and 17 (1.9%) in smokers (p=0.045). In multivariate analysis, only the female gender was a significant predictor of PJI (OR 1.3, 95% CI 1.1-2.4 [p=0.039]). Specifically, the categories of ex-smokers (OR 0.8, 95% CI 0.2-1.7 [p=0.241]) and smokers (OR 1.1, 95% CI 0.6-1.5 [p=0.052]) were not significant predictors. The 4-year arthroplasty survival with PJI as the endpoint was 99.1% (95% CI: 99.0-99.7) for nonsmokers, 99.0% (95% CI: 98.8-99.2) for ex-smokers, and 98.7% (95% CI: 98.2-99.0) for smokers was not significantly different between smoking status groups (p=0.318). DISCUSSION: Smoking was not identified as a significant predictor for PJI following primary TKA or THA. LEVEL OF EVIDENCE: III, prospective cohort study.


Asunto(s)
Artroplastia de Reemplazo de Cadera , Artroplastia de Reemplazo de Rodilla , Infecciones Relacionadas con Prótesis , Sistema de Registros , Reoperación , Fumar , Humanos , Masculino , Femenino , Artroplastia de Reemplazo de Cadera/efectos adversos , Artroplastia de Reemplazo de Rodilla/efectos adversos , Infecciones Relacionadas con Prótesis/etiología , Anciano , Persona de Mediana Edad , Fumar/efectos adversos , Estudios Prospectivos , Factores de Riesgo
13.
J Clin Med ; 13(5)2024 Feb 24.
Artículo en Inglés | MEDLINE | ID: mdl-38592707

RESUMEN

Background: Previous research has established good test-retest reliability for isokinetic dynamometry in fibromyalgia. However, the reliability of this test under dual-task conditions has not been investigated in fibromyalgia. Methods: A total of 10 women with fibromyalgia participated in this study. Participants completed the concentric/concentric test. The dual-task condition involved subtracting two by two while performing the test. Results: Reliability analysis under the single condition showed "poor" to "excellent" values for maximum peak torque in knee extension and "moderate" to "excellent" values for average. "Poor" to "excellent" reliability values were found in knee flexion for the maximum and average. Dual-task condition in knee extension ranged from "moderate" to "excellent" for maximum and average values, and in knee flexion, it ranged from "poor" to "excellent" for maximum value and from "moderate" to "excellent" for average value. Conclusions: Isokinetic dynamometry demonstrated sufficient reliability for measuring strength in knee extension maximum and average during single-task and dual-task conditions, along with knee flexion dual-task average in fibromyalgia. For knee flexion single-task maximum and average and knee flexion dual-task maximum, we did not obtain sufficiently reliable measurements. Only the concentric/concentric test has been studied, and future studies with a larger sample size are needed in order to generalize the results.

14.
Rev Esp Enferm Dig ; 2024 Apr 30.
Artículo en Inglés | MEDLINE | ID: mdl-38685904

RESUMEN

The complication rate for Pancreaticoduodenectomy (PD) is 40-50% in most published series and mortality can raise up to 4-5% even in high-volume centers. Severe portal hypertension secondary to liver disease is associated to high perioperative mortality and therefore is considered a contraindication for PD. No standardized management exists for surgically resectable patients with periampullary cancer and severe portal hypertension. The aim of this case study is to analyse the treatment alternatives in patients with periampullary cancer and severe portal hypertension and focus into the surgical treatment of these patients. We present the case of a 67 year-old patient case with a resectable ampullary cancer and portal hypertension managed with Preoperative Transjugular Intrahepatic Portosystemic Shunt (TIPS) to allow a PD. We present a literature review on the use of preoperative TIPS in patients who are candidates to PD. Neoadjuvant TIPS can be safely used in selected patients with severe portal hypertension who need a PD.

15.
Dalton Trans ; 53(18): 8041-8049, 2024 May 07.
Artículo en Inglés | MEDLINE | ID: mdl-38652019

RESUMEN

Octahedrally coordinated spin crossover (SCO) FeII complexes represent an important class of switchable molecular materials. This study presents the synthesis and characterisation of a novel complex, [FeII(ppt-2Fph)2]0·2MeOH, where ppt-2Fph is a new asymmetric ionogenic tridentate planar ligand 2-(5-(2-fluorophenyl)-4H-1,2,4-triazol-3-yl)-6-(1H-pyrazol-1-yl)pyridine. The complex exhibits a hysteretic thermally induced SCO transition at 285 K on cooling and at 293 K on heating, as well as light induced excited spin state trapping (LIESST) at lower temperatures with a relaxation T(LIESST) temperature of 73 K. Single crystal analysis in both spin states shows that the compound undergoes an unusual partial (25%) reversible order-disorder of the asymmetrically substituted phenyl group coupled to the thermal SCO. The highly cooperative SCO transition, analysed by structural energy framework analysis at the B3LYP/6-31G(d,p) theory level, revealed the co-existence of stabilising and destabilising energy variations in the lattice. The observed antagonism of intermolecular interactions and synchronous rotational disorder, which contributes to the overall entropy change, is suggested to be at the origin of the cooperative SCO transition.

16.
Proc Natl Acad Sci U S A ; 121(14): e2316101121, 2024 Apr 02.
Artículo en Inglés | MEDLINE | ID: mdl-38547068

RESUMEN

Though YB6 and LaB6 share the same crystal structure, atomic valence electron configuration, and phonon modes, they exhibit drastically different phonon-mediated superconductivity. YB6 superconducts below 8.4 K, giving it the second-highest critical temperature of known borides, second only to MgB2. LaB6 does not superconduct until near-absolute zero temperatures (below 0.45 K), however. Though previous studies have quantified the canonical superconductivity descriptors of YB6's greater Fermi-level (Ef) density of states and higher electron-phonon coupling (EPC), the root of this difference has not been assessed with full detail of the electronic structure. Through chemical bonding, we determine low-lying, unoccupied 4f atomic orbitals in lanthanum to be the key difference between these superconductors. These orbitals, which are not accessible in YB6, hybridize with π B-B bonds and bring this π-system lower in energy than the σ B-B bonds otherwise at Ef. This inversion of bands is crucial: the optical phonon modes we show responsible for superconductivity cause the σ-orbitals of YB6 to change drastically in overlap, but couple weakly to the π-orbitals of LaB6. These phonons in YB6 even access a crossing of electronic states, indicating strong EPC. No such crossing in LaB6 is observed. Finally, a supercell (the M k-point) is shown to undergo Peierls-like effects in YB6, introducing additional EPC from both softened acoustic phonons and the same electron-coupled optical modes as in the unit cell. Overall, we find that LaB6 and YB6 have fundamentally different mechanisms of superconductivity, despite their otherwise near-identity.

17.
Plant Physiol Biochem ; 209: 108520, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38522131

RESUMEN

In Arabidopsis, the plastidial isoform of phosphoglucose isomerase, PGI1, mediates growth and photosynthesis, likely due to its involvement in the vascular production of cytokinins (CK). To examine this hypothesis, we characterized pgi1-2 knockout plants impaired in PGI1 and pgi1-2 plants specifically expressing PGI1 in root tips and vascular tissues. Moreover, to investigate whether the phenotype of pgi1-2 plants is due to impairments in the plastidial oxidative pentose phosphate pathway (OPPP) or the glycolytic pathway, we characterized pgl3-1 plants with reduced OPPP and pfk4pfk5 knockout plants impaired in plastidial glycolysis. Compared with wild-type (WT) leaves, pgi1-2 leaves exhibited weaker expression of photosynthesis- and 2-C-methyl-D-erythritol 4-P (MEP) pathway-related proteins, and stronger expression of oxidative stress protection-related enzymes. Consistently, pgi1-2 leaves accumulated lower levels of chlorophyll, and higher levels of tocopherols, flavonols and anthocyanins than the WT. Vascular- and root tip-specific PGI1 expression countered the reduced photosynthesis, low MEP pathway-derived CK content, dwarf phenotype and the metabolic characteristics of pgi1-2 plants, reverting them to WT-like levels. Moreover, pgl3-1, but not pfk4pfk5 plants phenocopied pgi1-2. Histochemical analyses of plants expressing GUS under the control of promoter regions of genes encoding plastidial OPPP enzymes exhibited strong GUS activity in root tips and vascular tissues. Overall, our findings show that root tip and vascular PGI1-mediated plastidial OPPP activity affects photosynthesis and growth through mechanisms involving long-distance modulation of the leaf proteome by MEP pathway-derived CKs.


Asunto(s)
Arabidopsis , Vía de Pentosa Fosfato , Antocianinas/metabolismo , Fotosíntesis , Arabidopsis/metabolismo , Citocininas/metabolismo
18.
PLoS One ; 19(3): e0295368, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38507347

RESUMEN

The World Health Organization has recommended a range of social and health measures to mitigate the spread of coronavirus disease 2019 (COVID-19), including strategies such as quarantines, border closures, social distancing, and mask usage, among others. Specifically, the Chilean authorities implemented the "step-by-step" plan, built on the concept of dynamic quarantine. Numerous studies have examined the effectiveness of these quarantines in Chile during the pandemic, utilizing data published by the Chilean Ministry of Health. This study's primary aim was to enhance our understanding of quarantine effectiveness in Chile during the pandemic. We accomplished this by analyzing the distributional behavior of the time until the COVID-19 pandemic was deemed under control or not. In our study, we defined an event with two potential outcomes related to the instantaneous reproductive number (Rt), which signifies the time until a change in the event outcome occurs. Importantly, we did not predefine a specific temporal observation unit. These findings allowed us to complement the concept of effective quarantine by considering the dynamics generated by the protocols, such as phase 1 of the quarantine, in achieving natural herd immunity in response to the number of COVID-19 cases and Rt. We assessed the behavior of the mean and median residual lifetime until the initiation of controlled/uncontrolled episodes of the COVID-19 pandemic based on Rt in all regions of Chile. Despite variations in the distribution of residual times for controlled/uncontrolled episodes in different regions, there was a similar observation during the period considered (between March 2020 and March 2021): the mitigation measures did not produce a clear positive effect for controlling the epidemic. The residual times of episodes with Rr,t > 1 were not different from those episodes with Rr,t ≤ 1.


Asunto(s)
COVID-19 , Humanos , COVID-19/epidemiología , COVID-19/prevención & control , Cuarentena , Pandemias/prevención & control , Chile/epidemiología , SARS-CoV-2
19.
RSC Adv ; 14(3): 2070-2079, 2024 Jan 03.
Artículo en Inglés | MEDLINE | ID: mdl-38196901

RESUMEN

Our present study focuses on examining the thermal, structural and luminescent characteristics of sodium barium metaphosphate glasses doped with Sm3+. Glass samples with molar compositions (100 - y)[(50P2O5)-(50-xNa2O)-(xBaO)]-ySm2O3, where x = 20, 25, 30, 35, 40 and y = 0.3 and 1% were first synthesized by conventional melt quenching and later dehydroxylated under a constant N2 flow to ensure final glasses with a very high degree of chemical and optical homogeneity and free of water. Upon the addition of BaO and Sm2O3, refractive index, molar mass, density, glass transition temperature and dilatometric softening temperature exhibited an increase, whereas the coefficient of thermal expansion showed a decrease. The FTIR spectra analysis reveals a network depolymerization that intensifies with rising BaO concentration, ultimately transitioning from a modifier oxide to a glass-forming element, at higher BaO concentrations. All doped samples exhibited prominent absorption bands in the visible (VIS) and near-infrared (NIR) regions, as revealed by the optical absorption spectra. The Na2O modifier demonstrated greater influence on Sm3+ emission compared to BaO, a phenomenon that can explained by the moderation of the local ligand field strength resulting from this substitution. With an increase in Sm2O3 concentration from 0.3 to 1 mol%, the experimental lifetimes of the 4G5/2 level decrease, primarily attributed to the presence of energy transfer mechanisms. A discussion of Judd-Ofelt parameter analysis and glass radiation properties will be presented.

20.
Mol Biol Evol ; 41(2)2024 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-38285634

RESUMEN

Rainforest hunter-gatherers from Southeast Asia are characterized by specific morphological features including a particularly dark skin color (D), short stature (S), woolly hair (W), and the presence of steatopygia (S)-fat accumulation localized in the hips (DSWS phenotype). Based on previous evidence in the Andamanese population, we first characterized signatures of adaptive natural selection around the calcium-sensing receptor gene in Southeast Asian rainforest groups presenting the DSWS phenotype and identified the R990G substitution (rs1042636) as a putative adaptive variant for experimental follow-up. Although the calcium-sensing receptor has a critical role in calcium homeostasis by directly regulating the parathyroid hormone secretion, it is expressed in different tissues and has been described to be involved in many biological functions. Previous works have also characterized the R990G substitution as an activating polymorphism of the calcium-sensing receptor associated with hypocalcemia. Therefore, we generated a knock-in mouse for this substitution and investigated organismal phenotypes that could have become adaptive in rainforest hunter-gatherers from Southeast Asia. Interestingly, we found that mouse homozygous for the derived allele show not only lower serum calcium concentration but also greater body weight and fat accumulation, probably because of enhanced preadipocyte differentiation and lipolysis impairment resulting from the calcium-sensing receptor activation mediated by R990G. We speculate that such differential features in humans could have facilitated the survival of hunter-gatherer groups during periods of nutritional stress in the challenging conditions of the Southeast Asian tropical rainforests.


Asunto(s)
Polimorfismo Genético , Receptores Sensibles al Calcio , Animales , Humanos , Ratones , Calcio , Fenotipo , Receptores Sensibles al Calcio/genética , Selección Genética
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