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Aim: To compare the safety in terms of hypoglycemic events and continuous glucose monitoring (CGM) metrics during aerobic exercise (AE) of using temporary target (TT) versus suspension of insulin infusion (SII) in adults with type 1 diabetes (T1D) using advanced hybrid closed-loop systems. Methods: This was a randomized crossover clinical trial. Two moderate-intensity AE sessions were performed, one with TT and one with SII. Hypoglycemic events and CGM metrics were analyzed during the immediate (baseline to 59 min), early (60 min to 6 h), and late (6 to 36 h) post-exercise phases. Results: In total, 33 patients were analyzed (44.6 ± 13.8 years), basal time in range (%TIR 70-180 mg/dL) was 79.4 ± 12%, and time below range (%TBR) <70 mg/dL was 1.8 ± 1.7% and %TBR <54 mg/dL was 0.5 ± 0.9%. No difference was found in the number of hypoglycemic events, %TBR <70 mg/dL and %TBR <54 mg/dL between TT and SII. Differences were found in the early phase, with better values when using TT for %TIR 70-180 mg/dL (83.0 vs. 65.3, P = 0.005), time in tight range (%TITR 70-140 mg/dL) (56.3 vs. 41.5, P = 0.04), and time above range (%TAR >180 mg/dL) (15.3 vs. 31.8, P = 0.01). In the diurnal period, again %TIR was better for TT use (82.1 vs. 73.1, P = 0.02) and %TAR (15.0 vs. 22.96, P = 0.04). No significant differences were found in the CGM metrics during the different phases of AE. Conclusion: Our data appear to show that the use of TT compared with SII is equally safe in all phases of AE. However, the use of TT allows for a better glycemic profile in the early phase of exercise.

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Resumen El síndrome de ataxia cerebelosa, neuropatía y arre flexia vestibular (CANVAS) es un trastorno neurodege nerativo progresivo que se manifiesta en etapas tardías de la vida. Su base genética ha sido recientemente identificada en el gen que codifica la subunidad 1 del factor C de replicación (RFC1). Presentamos el caso de una mujer de 62 años con una historial de desequilibrio y deterioro de la marcha de presentación bifásica, con un inicio rápido de los sínto mas seguido de un deterioro neurológico lento y progre sivo. El proceso diagnóstico fue complejo y se realizaron numerosas pruebas para descartar causas adquiridas y genéticas de la ataxia, arribando al diagnóstico de ataxia cerebelosa de inicio tardío idiopática. Ulteriormente, las pruebas de función vestibular identificaron una grave vestibulopatía bilateral. Esto llevó a considerar el CANVAS entre los diagnósticos, que finalmente fue confirmado mediante pruebas genéticas (expansión bialélica del penta-nucleótido AAGGG en el gen RFC1). Este caso subraya la importancia de esta nueva enfer medad genética y su variante de presentación subaguda y enfatiza la relevancia de las pruebas objetivas de fun ción vestibular en las ataxias consideradas idiopáticas para lograr un diagnóstico adecuado y un eventual asesoramiento genético a la descendencia.

Abstract Cerebellar ataxia, neuropathy, and vestibular areflexia syndrome (CANVAS) is a late onset neurodegenerative disorder. Its genetic basis has recently been identified in the gene encoding a subunit of the Replication Fac tor C (RFC1). We present the case of a 62-year-old woman who expe rienced a history of a biphasic presentation of imbalance and gait disorders, with rapid onset of symptoms followed by slow and progressive neurological deterioration. The diagnostic process was challenging, and numerous tests were conducted to rule out acquired and genetic causes of ataxia, leading to a diagnosis of late-onset idiopathic cer ebellar ataxia. Subsequently, vestibular function tests iden tified severe bilateral vestibulopathy. This led to consider ing CANVAS among the diagnoses, which was ultimately confirmed through genetic testing (biallelic expansion of the pentanucleotide AAGGG in the RFC1 gene). This case highlights the importance of this new de scribed genetic disease and its subacute presentation variant, emphasizing the relevance of objective vestibu lar function tests in idiopathic ataxias to achieve proper diagnosis and eventual genetic counseling for offspring.

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Dinitrogen trioxide ( N 2 O 3 ) mediates low-molecular weight and protein S- and N-nitrosation, with recent reports suggesting a role in the formation of nitrating intermediates as well as in nitrite-dependent hypoxic vasodilatation. However, the reactivity of N 2 O 3 in biological systems results in an extremely short half-life that renders this molecule essentially undetectable by currently available technologies. As a result, evidence for in vivo N 2 O 3 formation derives from the detection of nitrosated products as well as from in vitro kinetic determinations, isotopic labeling studies, and spectroscopic analyses. This review will discuss mechanisms of N 2 O 3 formation, reactivity and decomposition, as well as address the role of sub-cellular localization as a key determinant of its actions. Finally, evidence will be discussed supporting different roles for N 2 O 3 as a biologically relevant signaling molecule.

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Colorectal cancer (CRC) is a significant global health concern. Prognostication of CRC traditionally relies on the Union for International Cancer Control (UICC) and American Joint Committee on Cancer (AJCC) TNM staging classifications, yet clinical outcomes often vary independently of stage. Despite similarities, rectal and colon cancers are distinct in their diagnostic methodologies and treatments, with MRI and CT scans primarily used for staging rectal and colon cancers, respectively. This paper examines the challenges in accurately assessing prognostic factors of colon cancer such as primary tumor extramural extension, retroperitoneal surgical margin (RSM) involvement, extramural vessel invasion (EMVI), and lymph node metastases through preoperative CT and MRI. It highlights the importance of these factors in risk stratification, treatment decisions, and surgical planning for colon cancer patients. Advancements in imaging techniques are crucial for improving clinical management and optimizing patient outcomes, underscoring the necessity for ongoing research to refine diagnostic methods and incorporate novel findings into practice.

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Due to the low temperature, the Antarctic marine environment is challenging for protein functioning. Cold-adapted organisms have evolved proteins endowed with higher flexibility and lower stability in comparison to their thermophilic homologs, resulting in enhanced reaction rates at low temperatures. The Antarctic bacterium Pseudoalteromonas haloplanktis TAC125 (PhTAC125) genome is one of the few examples of coexistence of multiple hemoglobin genes encoding, among others, two constitutively transcribed 2/2 hemoglobins (2/2Hbs), also named truncated Hbs (TrHbs), belonging to the Group II (or O), annotated as PSHAa0030 and PSHAa2217. In this work, we describe the ligand binding kinetics and their interrelationship with the dynamical properties of globin Ph-2/2HbO-2217 by combining experimental and computational approaches and implementing a new computational method to retrieve information from molecular dynamic trajectories. We show that our approach allows us to identify docking sites within the protein matrix that are potentially able to transiently accommodate ligands and migration pathways connecting them. Consistently with ligand rebinding studies, our modeling suggests that the distal heme pocket is connected to the solvent through a low energy barrier, while inner cavities play only a minor role in modulating rebinding kinetics.

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Cerebellar ataxia, neuropathy, and vestibular areflexia syndrome (CANVAS) is a late onset neurodegenerative disorder. Its genetic basis has recently been identified in the gene encoding a subunit of the Replication Factor C (RFC1). We present the case of a 62-year-old woman who experienced a history of a biphasic presentation of imbalance and gait disorders, with rapid onset of symptoms followed by slow and progressive neurological deterioration. The diagnostic process was challenging, and numerous tests were conducted to rule out acquired and genetic causes of ataxia, leading to a diagnosis of late-onset idiopathic cerebellar ataxia. Subsequently, vestibular function tests identified severe bilateral vestibulopathy. This led to considering CANVAS among the diagnoses, which was ultimately confirmed through genetic testing (biallelic expansion of the pentanucleotide AAGGG in the RFC1 gene). This case highlights the importance of this new described genetic disease and its subacute presentation variant, emphasizing the relevance of objective vestibular function tests in idiopathic ataxias to achieve proper diagnosis and eventual genetic counseling for offspring.

El síndrome de ataxia cerebelosa, neuropatía y arreflexia vestibular (CANVAS) es un trastorno neurodegenerativo progresivo que se manifiesta en etapas tardías de la vida. Su base genética ha sido recientemente identificada en el gen que codifica la subunidad 1 del factor C de replicación (RFC1). Presentamos el caso de una mujer de 62 años con una historial de desequilibrio y deterioro de la marcha de presentación bifásica, con un inicio rápido de los síntomas seguido de un deterioro neurológico lento y progresivo. El proceso diagnóstico fue complejo y se realizaron numerosas pruebas para descartar causas adquiridas y genéticas de la ataxia, arribando al diagnóstico de ataxia cerebelosa de inicio tardío idiopática. Ulteriormente, las pruebas de función vestibular identificaron una grave vestibulopatía bilateral. Esto llevó a considerar el CANVAS entre los diagnósticos, que finalmente fue confirmado mediante pruebas genéticas (expansión bialélica del penta-nucleótido AAGGG en el gen RFC1). Este caso subraya la importancia de esta nueva enfermedad genética y su variante de presentación subaguda y enfatiza la relevancia de las pruebas objetivas de función vestibular en las ataxias consideradas idiopáticas para lograr un diagnóstico adecuado y un eventual asesoramiento genético a la descendencia.

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Resumen El carcinoma sarcomatoide primario hepático es un tumor agresivo que representa el 0.4-0.7% de todas las neoplasias primarias hepáticas. Se asocia a hepa topatía por virus hepatotropos, es más prevalente en la población asiática y en su histología se evidencian componentes de carcinoma y sarcoma. No posee carac terísticas clínicas ni imagenológicas patognomónicas y su diagnóstico se realiza en base a los hallazgos de la anatomía patológica e inmunohistoquímica. La cirugía en estadio localizado representa la única modalidad terapéutica con impacto en la sobrevida. Reportamos el caso de una paciente de 72 años, coreana, con an tecedentes de hepatopatía crónica por virus B, a quien se le diagnosticó un carcinoma sarcomatoide hepático primario con metástasis ósea y ganglionares.

Abstract Primary hepatic sarcomatoid carcinoma is a very ag gressive tumor, representing 0.4-0.7% of all primary he patic neoplasms. The disease is associated with liver dis ease due to hepatotropic viruses and is more prevalent in Asians. Histology shows sarcomatous and carcinoma components. It does not have pathognomonic clinical or imaging characteristics and its diagnosis is based on the pathological and immunohistochemistry findings. Surgery could prolong survival in localized stages. We report the case of a 72-year-old Korean patient with a history of chronic liver disease due to B virus, who was diagnosed with primary hepatic sarcomatoid carcinoma with bone and lymph node metastases.

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Nitrobindins (Nbs) are all-ß-barrel heme proteins present along the evolutionary ladder. They display a highly solvent-exposed ferric heme group with the iron atom being coordinated by the proximal His residue and a water molecule at the distal position. Ferric nitrobindins (Nb(III)) play a role in the conversion of toxic peroxynitrite (ONOO-) to harmless nitrate, with the value of the second-order rate constant being similar to those of most heme proteins. The value of the second-order rate constant of Nbs increases as the pH decreases; this suggests that Nb(III) preferentially reacts with peroxynitrous acid (ONOOH), although ONOO- is more nucleophilic. In this work, we shed light on the molecular basis of the ONOO- and ONOOH reactivity of ferric Mycobacterium tuberculosis Nb (Mt-Nb(III)) by dissecting the ligand migration toward the active site, the water molecule release, and the ligand binding process by computer simulations. Classical molecular dynamics simulations were performed by employing a steered molecular dynamics approach and the Jarzynski equality to obtain ligand migration free energy profiles for both ONOO- and ONOOH. Our results indicate that ONOO- and ONOOH migration is almost unhindered, consistent with the exposed metal center of Mt-Nb(III). To further analyze the ligand binding process, we computed potential energy profiles for the displacement of the Fe(III)-coordinated water molecule using a hybrid QM/MM scheme at the DFT level and a nudged elastic band approach. These results indicate that ONOO- exhibits a much larger barrier for ligand displacement than ONOOH, suggesting that water displacement is assisted by protonation of the leaving group by the incoming ONOOH.

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Machine learning (ML) methods have reached high accuracy levels for the prediction of in vacuo molecular properties. However, the simulation of large systems solely through ML methods (such as those based on neural network potentials) is still a challenge. In this context, one of the most promising frameworks for integrating ML schemes in the simulation of complex molecular systems are the so-called ML/MM methods. These multiscale approaches combine ML methods with classical force fields (MM), in the same spirit as the successful hybrid quantum mechanics-molecular mechanics methods (QM/MM). The key issue for such ML/MM methods is an adequate description of the coupling between the region of the system described by ML and the region described at the MM level. In the context of QM/MM schemes, the main ingredient of the interaction is electrostatic, and the state of the art is the so-called electrostatic-embedding. In this study, we analyze the quality of simpler mechanical embedding-based approaches, specifically focusing on their application within a ML/MM framework utilizing atomic partial charges derived in vacuo. Taking as reference electrostatic embedding calculations performed at a QM(DFT)/MM level, we explore different atomic charges schemes, as well as a polarization correction computed using atomic polarizabilites. Our benchmark data set comprises a set of about 80k small organic structures from the ANI-1x and ANI-2x databases, solvated in water. The results suggest that the minimal basis iterative stockholder (MBIS) atomic charges yield the best agreement with the reference coupling energy. Remarkable enhancements are achieved by including a simple polarization correction.

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We propose minimal transport experiments in the coherent regime that can probe the chirality of twisted moiré structures. We show that only with a third contact and in the presence of an in-plane magnetic field (or another time-reversal symmetry breaking effect) a chiral system may display nonreciprocal transport in the linear regime. We then propose to use the third lead as a voltage probe and show that opposite enantiomers give rise to different voltage drops on the third lead. Additionally, in the scenario of layer-discriminating contacts, the third lead can serve as a current probe capable of detecting different handedness even in the absence of a magnetic field. In a complementary configuration, applying opposite voltages on the two layers of the third lead gives rise to a chiral (super)current in the absence of a source-drain voltage whose direction is determined by its chirality.

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Primary hepatic sarcomatoid carcinoma is a very aggressive tumor, representing 0.4-0.7% of all primary hepatic neoplasms. The disease is associated with liver disease due to hepatotropic viruses and is more prevalent in Asians. Histology shows sarcomatous and carcinoma components. It does not have pathognomonic clinical or imaging characteristics and its diagnosis is based on the pathological and immunohistochemistry findings. Surgery could prolong survival in localized stages. We report the case of a 72-year-old Korean patient with a history of chronic liver disease due to B virus, who was diagnosed with primary hepatic sarcomatoid carcinoma with bone and lymph node metastases.

El carcinoma sarcomatoide primario hepático es un tumor agresivo que representa el 0.4-0.7% de todas las neoplasias primarias hepáticas. Se asocia a hepatopatía por virus hepatotropos, es más prevalente en la población asiática y en su histología se evidencian componentes de carcinoma y sarcoma. No posee características clínicas ni imagenológicas patognomónicas y su diagnóstico se realiza en base a los hallazgos de la anatomía patológica e inmunohistoquímica. La cirugía en estadio localizado representa la única modalidad terapéutica con impacto en la sobrevida. Reportamos el caso de una paciente de 72 años, coreana, con antecedentes de hepatopatía crónica por virus B, a quien se le diagnosticó un carcinoma sarcomatoide hepático primario con metástasis ósea y ganglionares.

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BACKGROUND: This study investigated the characteristics associated with an increased risk of hypoglycemia, in elderly patients with type 1 diabetes mellitus (T1D) using automated insulin delivery (AID) systems. METHODS: Cross-sectional observational study including patients >60 years, using sensor-augmented insulin pump therapy with predictive low-glucose management (SAPT-PLGM), hybrid closed-loop (HCL), and advanced hybrid closed-loop (AHCL), for more than three months. A geriatric assessment was performed, and body composition was determined to investigate its association with achieving time below range (TBR) <70 mg/dL goals. RESULTS: The study included 59 patients (47.5% of men, mean age of 67.6 years, glycated hemoglobin [HbA1c] of 7.5 ± 0.6%, time in range (TIR) 77.8 ± 9.9%). Time below range <70 and <54 mg/dL were 2.2 ± 2.3% and 0.4 ± 0.81%, respectively. Patients with elevated TBR <70 mg/dL (>1%) had higher HbA1c levels, lower TIR, elevated time above range (TAR), and high glycemic variability. Regarding body composition, greater muscle mass, grip strength, and visceral fat were associated with a lower TBR <70 mg/dL. These factors were independent of the type of technology used, but TIR was higher when using AHCL systems compared with SAPT-PLGM and HCL systems. CONCLUSIONS: In elderly patients treated with AID systems with good functional status, lower lean mass, lower grip strength, and lower visceral fat percentage were associated with TBR greater than 1%, regardless of the device used. A similar finding along was found with CGM indicators such as higher HbA1c levels, lower TIR, higher TAR, and higher CV. Geriatric assessment is crucial for personalizing patient management.

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Round rays (family: Urotrygonidae) are commonly caught as by-catch by shrimp trawl fisheries in the tropical eastern Pacific (TEP). However, little information on their life history and catch species composition exists for most round ray species, preventing the evaluation of the impact of fishing on their populations. The mean size at sexual maturity (DW50), seasonal variation by maturity stages, and fecundity for two round ray species caught during shrimp trawl research cruises in the south-eastern Gulf of California (northern TEP) were estimated using a multi-model approach and inference for the first time, to determine the part of the population of each species that is being affected by shrimp trawling. Disc width (DW) ranged from 7.0 to 30.9 cm for the spotted round ray (Urobatis maculatus), and 7.2-33.5 cm for the thorny stingray (Urotrygon rogersi), with females reaching larger sizes than males in both species. The DW50 was estimated at 12.8 and 11.8 cm DW for the males and females of U. maculatus, respectively, whereas for U.rogersi, it was 15.0 and 18.4 cm DW for males and females, respectively. Embryos were found in females ≥14.5 cm DW in both species. The maximum fecundity was five embryos for U. maculatus (mean = 3.1 ± 0.2 S.E., mode = 4), and six embryos for U. rogersi (mean = 3.0 ± 0.3 S.E., mode = 2). Fecundity and embryo size did not vary with maternal size. Male and female immature and mature individuals for both species, including pregnant females, were found in the catches in all seasons of the year. Our results can help determine the vulnerability of the studied species populations to fishing pressure from shrimp trawling in the northern TEP and guide the development of future monitoring strategies and conservation actions for these species, if necessary.

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The stochastic synthesis of extreme, rare climate scenarios is vital for risk and resilience models aware of climate change, directly impacting society in different sectors. However, creating high-quality variations of under-represented samples remains a challenge for several generative models. This paper investigates quantizing reconstruction losses for helping variational autoencoders (VAE) better synthesize extreme weather fields from conventional historical training sets. Building on the classical VAE formulation using reconstruction and latent space regularization losses, we propose various histogram-based penalties to the reconstruction loss that explicitly reinforces the model to synthesize under-represented values better. We evaluate our work using precipitation weather fields, where models usually strive to synthesize well extreme precipitation samples. We demonstrate that bringing histogram awareness to the reconstruction loss improves standard VAE performance substantially, especially for extreme weather events.

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BACKGROUND: The information on functional decline after hospitalization for COVID-19 is limited in older adults (OAs). OBJECTIVE: To determine the association of inflammation (ferritin) and coagulation markers (D-dimer) and clinical factors with the functional status of OAs who suffered from COVID-19 six months after hospital discharge in Mexico. MATERIAL AND METHODS: Ambispective cohort study of 158 patients older than 65 years hospitalized for moderate-severe COVID-19 with complete electronic records that would allow to collect information and to contact them six months after discharge. Functional impairment was defined as a decrease ≥ 10 points on the Barthel index. Using logistic regression analysis, the risk of association of biochemical and clinical factors with functional deterioration during follow-up was determined. RESULTS: 46.2% of participants exhibited functional decline. Associated factors included age ≥ 73 years (OR = 2.53), chronic kidney disease (OR = 4.57), an ABC-Goals score ≥ 8 (OR = 2.4), ferritin ≥ 605 ng/mL (OR = 3.94) and D-dimer ≥ 930 ng/mL (OR = 17.56). CONCLUSION: COVID-19 infection did not only represent a disease with a high risk of mortality during the acute phase, but is also associated with a high risk of functional impairment after hospital discharge.

ANTECEDENTES: La información acerca del deterioro funcional después de una hospitalización por COVID-19 es limitada en personas mayores (PM). OBJETIVO: Determinar la asociación entre marcadores de inflamación (ferritina), coagulación (dímero D), factores clínicos y el estado funcional de PM que padecieron COVID-19 a seis meses del alta hospitalaria en México. MATERIAL Y MÉTODOS: Estudio de cohorte ambispectiva de 158 pacientes mayores de 65 años hospitalizados por COVID-19 moderado-grave con expediente electrónico completo que permitiera recolectar información y contactarlos a los seis meses del alta. Se definió deterioro funcional como disminución ≥ 10 puntos del índice de Barthel. Mediante regresión logística se determinó el riesgo de asociación entre factores bioquímicos y clínicos y deterioro funcional en el tiempo de seguimiento. RESULTADOS: 46.2 % de los participantes presentó pérdida funcional. Los factores asociados fueron edad ≥ 73 años (RM = 2.53), enfermedad renal crónica (RM = 4.57), puntuación ABC-Goals ≥ 8 (RM = 2.4), ferritina ≥ 605 ng/mL (RM = 3.94) y dímero-D ≥ 930 ng/mL FEU (RM = 17.56). CONCLUSIÓN: La infección por COVID-19 no solo representa una enfermedad con alto riesgo de mortalidad durante la fase aguda, sino que también se asocia a un alto riesgo de deterioro funcional posterior al egreso hospitalario.

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Challenging the basis of our chemical intuition, recent experimental evidence reveals the presence of a new type of intrinsic fluorescence in biomolecules that exists even in the absence of aromatic or electronically conjugated chemical compounds. The origin of this phenomenon has remained elusive so far. In the present study, we identify a mechanism underlying this new type of fluorescence in different biological aggregates. By employing non-adiabatic ab initio molecular dynamics simulations combined with a data-driven approach, we characterize the typical ultrafast non-radiative relaxation pathways active in non-fluorescent peptides. We show that the key vibrational mode for the non-radiative decay towards the ground state is the carbonyl elongation. Non-aromatic fluorescence appears to emerge from blocking this mode with strong local interactions such as hydrogen bonds. While we cannot rule out the existence of alternative non-aromatic fluorescence mechanisms in other systems, we demonstrate that this carbonyl-lock mechanism for trapping the excited state leads to the fluorescence yield increase observed experimentally, and set the stage for design principles to realize novel non-invasive biocompatible probes with applications in bioimaging, sensing, and biophotonics.

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Resumen Antecedentes: La información acerca del deterioro funcional después de una hospitalización por COVID-19 es limitada en personas mayores (PM). Objetivo: Determinar la asociación entre marcadores de inflamación (ferritina), coagulación (dímero D), factores clínicos y el estado funcional de PM que padecieron COVID-19 a seis meses del alta hospitalaria en México. Material y métodos: Estudio de cohorte ambispectiva de 158 pacientes mayores de 65 años hospitalizados por COVID-19 moderado-grave con expediente electrónico completo que permitiera recolectar información y contactarlos a los seis meses del alta. Se definió deterioro funcional como disminución ≥ 10 puntos del índice de Barthel. Mediante regresión logística se determinó el riesgo de asociación entre factores bioquímicos y clínicos y deterioro funcional en el tiempo de seguimiento. Resultados: 46.2 % de los participantes presentó pérdida funcional. Los factores asociados fueron edad ≥ 73 años (RM = 2.53), enfermedad renal crónica (RM = 4.57), puntuación ABC-Goals ≥ 8 (RM = 2.4), ferritina ≥ 605 ng/mL (RM = 3.94) y dímero-D ≥ 930 ng/mL FEU (RM = 17.56). Conclusión: La infección por COVID-19 no solo representa una enfermedad con alto riesgo de mortalidad durante la fase aguda, sino que también se asocia a un alto riesgo de deterioro funcional posterior al egreso hospitalario.

Abstract Background: The information on functional decline after hospitalization for COVID-19 is limited in older adults (OAs). Objective: To determine the association of inflammation (ferritin) and coagulation markers (D-dimer) and clinical factors with the functional status of OAs who suffered from COVID-19 six months after hospital discharge in Mexico. Material and methods: Ambispective cohort study of 158 patients older than 65 years hospitalized for moderate-severe COVID-19 with complete electronic records that would allow to collect information and to contact them six months after discharge. Functional impairment was defined as a decrease ≥ 10 points on the Barthel index. Using logistic regression analysis, the risk of association of biochemical and clinical factors with functional deterioration during follow-up was determined. Results: 46.2 % of participants exhibited functional decline. Associated factors included age ≥ 73 years (OR = 2.53), chronic kidney disease (OR = 4.57), an ABC-Goals score ≥ 8 (OR = 2.4), ferritin ≥ 605 ng/mL (OR = 3.94) and D-dimer ≥ 930 ng/mL (OR = 17.56). Conclusion: COVID-19 infection did not only represent a disease with a high risk of mortality during the acute phase, but is also associated with a high risk of functional impairment after hospital discharge.

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The determination of minimum free energy pathways (MFEP) is one of the most widely used strategies to study reactive processes. For chemical reactions in complex environments, the combination of quantum mechanics (QM) with a molecular mechanics (MM) representation is usually necessary in a hybrid QM/MM framework. However, even within the QM/MM approximation, the affordable sampling of the phase space is, in general, quite restricted. To reduce drastically the computational cost of the simulations, several methods such as umbrella sampling require performing a priori a selection of a reaction coordinate. The quality of the computed results, in an affordable computational time, is intimately related to the reaction coordinate election which is, in general, a nontrivial task. In this work, we provide an approach to model reactive processes in complex environments that does not require the a priori selection of a reaction coordinate. The proposed methodology combines QM/MM simulations with an extrapolation of the nudged elastic bands (NEB) method to the free energy surface (FENEB). We present and apply our own FENEB scheme to optimize MFEP in different reactive processes, using QM/MM frameworks at semiempirical and density functional theory levels. Our implementation is based on performing the FENEB optimization by uncoupling the optimization of the band in a perpendicular and tangential direction. In each step, a full optimization with the spring force is performed, which guarantees that the images remain evenly distributed. The robustness of the method and the influence of sampling on the quality of the optimized MFEP and its associated free energy barrier are studied. We show that the FENEB method provides a good estimation of the reaction barrier even with relatively short simulation times, supporting that its combination with QM/MM frameworks provides an adequate tool to study chemical processes in complex environments.

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The mechanism of the metal centered reduction of metmyoglobin (MbFeIII) by sulfide species (H2S/HS-) under an argon atmosphere has been studied by a combination of spectroscopic, kinetic, and computational methods. Asymmetric S-shaped time-traces for the formation of MbFeII at varying ratios of excess sulfide were observed at pH 5.3 < pH < 8.0 and 25 °C, suggesting an autocatalytic reaction mechanism. An increased rate at more alkaline pHs points to HS- as relevant reactive species for the reduction. The formation of the sulfanyl radical (HS•) in the slow initial phase was assessed using the spin-trap phenyl N-tert-butyl nitrone. This radical initiates the formation of S-S reactive species as disulfanuidyl/ disulfanudi-idyl radical anions and disulfide (HSSH•-/HSS•2- and HSS-, respectively). The autocatalysis has been ascribed to HSS-, formed after HSSH•-/HSS•2- disproportionation, which behaves as a fast reductant toward the intermediate complex MbFeIII(HS-). We propose a reaction mechanism for the sulfide-mediated reduction of metmyoglobin where only ferric heme iron initiates the oxidation of sulfide species. Beside the chemical interest, this insight into the MbFeIII/sulfide reaction under an argon atmosphere is relevant for the interpretation of biochemical aspects of ectopic myoglobins found on hypoxic tissues toward reactive sulfur species.

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The interactions of the heme iron of hemeproteins with sulfide and disulfide compounds are of potential interest as physiological signaling processes. While the interaction with hydrogen sulfide has been described computationally and experimentally, the reaction with disulfide, and specifically the molecular mechanism for ligand binding has not been studied in detail. In this work, we study the association process for disulfane and its conjugate base disulfanide at different pH conditions. Additionally, by means of advanced sampling techniques based on multiple steered molecular dynamics, we provide free energy profiles for ligand migration for both acid/base species, showing a similar behavior to the previously reported for the related H2S/HS¯ pair. Finally, we studied the ligand interchange reaction (H2O/H2S, HS¯ and H2O/HSSH, HSS¯) by means of hybrid quantum mechanics-molecular mechanics calculations. We show that the anionic species are able to displace more efficiently the H2O bound to the iron, and that the H-bond network in the distal cavity can help the neutral species to perform the reaction. Altogether, we provide a molecular explanation for the experimental information and show that the global association process depends on a fine balance between the migration towards the active site and the ligand interchange reaction.

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