Malignant Central Airway Obstruction: What's New?

Malignant central airway obstruction (MCAO) is a debilitating and life-limiting complication that occurs in an unfortunately large number of individuals with advanced intrathoracic cancer. Although the management of MCAO is multimodal and interdisciplinary, the task of providing patients with prompt palliation falls increasingly on the shoulders of interventional pulmonologists. While a variety of tools and techniques are available for the management of malignant obstructive lesions, advancements and evolution in this therapeutic venue have been somewhat sluggish and limited when compared with other branches of interventional pulmonary medicine (e.g., the early diagnosis of peripheral lung nodules). Indeed, one pragmatic, albeit somewhat uncharitable, reading of this article's title might suggest a wry smile and shug of the shoulders as to imply that relatively little has changed in recent years. That said, the spectrum of interventions for MCAO continues to expand, even if at a less impressive clip. Herein, we present on MCAO and its endoscopic and nonendoscopic management-that which is old, that which is new, and that which is still on the horizon.

In Silico Analysis of Metabolites from Peruvian Native Plants as Potential Therapeutics against Alzheimer's Disease.

BACKGROUND: Despite research on the molecular bases of Alzheimer's disease (AD), effective therapies against its progression are still needed. Recent studies have shown direct links between AD progression and neurovascular dysfunction, highlighting it as a potential target for new therapeutics development. In this work, we screened and evaluated the inhibitory effect of natural compounds from native Peruvian plants against tau protein, amyloid beta, and angiotensin II type 1 receptor (AT1R) pathologic AD markers. METHODS: We applied in silico analysis, such as virtual screening, molecular docking, molecular dynamics simulation (MD), and MM/GBSA estimation, to identify metabolites from Peruvian plants with inhibitory properties, and compared them to nicotinamide, telmisartan, and grapeseed extract drugs in clinical trials. RESULTS: Our results demonstrated the increased bioactivity of three plants' metabolites against tau protein, amyloid beta, and AT1R. The MD simulations indicated the stability of the AT1R:floribundic acid, amyloid beta:rutin, and tau:brassicasterol systems. A polypharmaceutical potential was observed for rutin due to its high affinity to AT1R, amyloid beta, and tau. The metabolite floribundic acid showed bioactivity against the AT1R and tau, and the metabolite brassicasterol showed bioactivity against the amyloid beta and tau. CONCLUSIONS: This study has identified molecules from native Peruvian plants that have the potential to bind three pathologic markers of AD.

Structural and Functional Analysis of Female Sex Hormones against SARS-CoV-2 Cell Entry.

Emerging evidence suggests that males are more susceptible to severe infection by the SARS-CoV-2 virus than females. A variety of mechanisms may underlie the observed gender-related disparities including differences in sex hormones. However, the precise mechanisms by which female sex hormones may provide protection against SARS-CoV-2 infectivity remains unknown. Here we report new insights into the molecular basis of the interactions between the SARS-CoV-2 spike (S) protein and the human ACE2 receptor. We further report that glycosylation of the ACE2 receptor enhances SARS-CoV-2 infectivity. Importantly, estrogens can disrupt glycan-glycan interactions and glycan-protein interactions between the human ACE2 and the SARS-CoV-2 thereby blocking its entry into cells. In a mouse model of COVID-19, estrogens reduced ACE2 glycosylation and thereby alveolar uptake of the SARS-CoV-2 spike protein. These results shed light on a putative mechanism whereby female sex hormones may provide protection from developing severe infection and could inform the development of future therapies against COVID-19.

Bringing high spatial resolution to the far-infrared: A giant leap for astrophysics.

The far-infrared (FIR) regime is one of the wavelength ranges where no astronomical data with sub-arcsecond spatial resolution exist. None of the medium-term satellite projects like SPICA, Millimetron, or the Origins Space Telescope will resolve this malady. For many research areas, however, information at high spatial and spectral resolution in the FIR, taken from atomic fine-structure lines, from highly excited carbon monoxide (CO), light hydrides, and especially from water lines would open the door for transformative science. A main theme will be to trace the role of water in proto-planetary discs, to observationally advance our understanding of the planet formation process and, intimately related to that, the pathways to habitable planets and the emergence of life. Furthermore, key observations will zoom into the physics and chemistry of the star-formation process in our own Galaxy, as well as in external galaxies. The FIR provides unique tools to investigate in particular the energetics of heating, cooling, and shocks. The velocity-resolved data in these tracers will reveal the detailed dynamics engrained in these processes in a spatially resolved fashion, and will deliver the perfect synergy with ground-based molecular line data for the colder dense gas.

Complications in Pediatric Regional Anesthesia: An Analysis of More than 100,000 Blocks from the Pediatric Regional Anesthesia Network.

WHAT WE ALREADY KNOW ABOUT THIS TOPIC: WHAT THIS ARTICLE TELLS US THAT IS NEW: BACKGROUND:: Complications in pediatric regional anesthesia are rare, so a large sample size is necessary to quantify risk. The Pediatric Regional Anesthesia Network contains data on more than 100,000 blocks administered at more than 20 children's hospitals. This study analyzed the risk of major complications associated with regional anesthesia in children. METHODS: This is a prospective, observational study of routine clinical practice. Data were collected on every regional block placed by an anesthesiologist at participating institutions and were uploaded to a secure database. The data were audited at multiple points for accuracy. RESULTS: There were no permanent neurologic deficits reported (95% CI, 0 to 0.4:10,000). The risk of transient neurologic deficit was 2.4:10,000 (95% CI, 1.6 to 3.6:10,000) and was not different between peripheral and neuraxial blocks. The risk of severe local anesthetic systemic toxicity was 0.76:10,000 (95% CI, 0.3 to 1.6:10,000); the majority of cases occurred in infants. There was one epidural abscess reported (0.76:10,000, 95% CI, 0 to 4.8:10,000). The incidence of cutaneous infections was 0.5% (53:10,000, 95% CI, 43 to 64:10,000). There were no hematomas associated with neuraxial catheters (95% CI, 0 to 3.5:10,000), but one epidural hematoma occurred with a paravertebral catheter. No additional risk was observed with placing blocks under general anesthesia. The most common adverse events were benign catheter-related failures (4%). CONCLUSIONS: The data from this study demonstrate a level of safety in pediatric regional anesthesia that is comparable to adult practice and confirms the safety of placing blocks under general anesthesia in children.

Fresh and cryopreserved ovary transplantation and resting follicle recruitment.

Ovary cryopreservation and transplantation has garnered increasing interest as a possible method to preserve fertility for cancer patients and to study ovarian resting follicle recruitment. Eleven consecutive women underwent fresh donor ovary transplantation, and 11 underwent cryopreserved ovary auto-transplantation in the same centre, with the same surgeon. Of the 11 fresh transplant recipients, who were all young but menopausal, nine women had normal ovarian cortex transplanted from an identical twin sister, and two had a fresh allograft from a non-identical sister. In the second group, 11 women with cancer had ovarian tissue cryopreserved before bone marrow transplant, and then after years of therapeutically induced menopause, underwent cryopreserved ovarian cortex autotransplantation. Recovery of ovarian function and follicle recruitment was assessed in all 22 recipients, and the potential for pregnancy was further investigated in 19 (11 fresh and 8 cryopreserved) with over 1-year follow-up. In all recipients, normal FSH levels and menstruation returned by about 150 days, and anti-Müllerian hormone reached much greater than normal concentrations by about 170 days. Anti-Müllerian hormone levels then fell below normal by about 240 days and remained at that lower level. Seventeen babies have been born to these 11 fresh and eight cryopreserved ovary transplant recipients.

Influence of the Water Model on the Structure and Interactions of the GPR40 Protein with the Lipid Membrane and the Solvent: Rigid versus Flexible Water Models.

G protein-coupled receptors (GPCR) are responsible for modulating various physiological functions and are thus related to the pathophysiology of different diseases. Being potential therapeutic targets, multiple computational methodologies have been developed to analyze their behavior and interactions with other species. The solvent, on the other hand, has received much less attention. In this work, we analyzed the effect of four explicit water models on the structure and interactions of the GPR40 receptor in its apo form. We employed the rigid SPC/E and TIP4P models, and their flexible versions, the FBA/ϵ and TIP4P/ϵflex. We explored the structural changes and their correlation with some bulk dynamic properties of water. Our results showed an adverse effect on the conservation of the secondary structure of the receptor with all the models due to the breaking of the intramolecular hydrogen bond network, being more evident for the TIP4P models. Notably, all four models brought the receptor to states similar to the active one, modifying the intracellular part of the TM5 and TM6 domains in a "hinge" type movement, allowing the opening of the structure. Regarding the dynamic properties, the rigid models showed results comparable to those obtained in other studies on membrane systems. However, flexible models exhibit disparities in the molecular representation of systems. Surprisingly, the FBA/ϵ model improves the molecular picture of several properties, even though their agreement with bulk diffusion is poorer. These findings reinforce our idea that exploring other water models or improving the current ones, to better represent the membrane interface, can lead to a positive impact on the description of the signal transduction mechanisms and the search of new drugs by targeting these receptors.

Killip and Kimball classification in the Ultrasound era: Is it time to redefine?

Lung ultrasound is a tool that is increasingly gaining strength in the initial evaluation of the patient in the emergency department and in critical care areas, making it particularly useful for cardiologists. In patients with ST elevation and acute myocardial infarction it has been observed that 25-45% of patients are wrongly classified as Class I in the Killip and Kimball classification after lung ultrasound (subclinical congestion). The clinical relevance of this finding lies in the fact that the greater the number of B lines, the greater short- and long-term the mortality is. An important advantage is that no prolonged time for learning the technique is required. More studies are needed to evaluate the role and importance of subclinical congestion in patients with acute myocardial infarction. Unfortunately, ultrasound is not widely available in developing countries, so the physical examination will continue to play an important role in the initial evaluation of patients with acute myocardial infraction.

El ultrasonido pulmonar es una herramienta que va cobrando más fuerza en la evaluación inicial del paciente en urgencias y en áreas de cuidados críticos, siendo de especial utilidad para el cardiólogo. Se ha observado que entre el 25 y el 45% de los pacientes con infarto agudo de miocardio con elevación del segmento ST se clasifican erróneamente como Clase 1 en la escala de Killip y Kimball después del ultrasonido pulmonar (congestión subclínica). La relevancia clínica de este hallazgo radica en que cuanto mayor es el número de líneas B, mayor es la mortalidad a corto y largo plazo. Una ventaja importante de esta herramienta es que no se requiere un tiempo prolongado para aprender la técnica. Se necesitan más estudios para evaluar el papel y la importancia de la congestión subclínica en pacientes con infarto agudo de miocardio. Desafortunadamente, el ultrasonido no está ampliamente disponible en los países en desarrollo, por lo que el examen físico seguirá desempeñando un papel importante para la evaluación inicial en pacientes con infarto agudo de miocardio.

Latin-American guidelines of recommendations at discharge from an acute coronary syndrome.

The diagnostic criteria, treatments at the time of admission, and drugs used in patients with acute coronary syndrome are well defined in countless guidelines. However, there is uncertainty about the measures to recommend during patient discharge planning. This document brings together the most recent evidence and the standardized and optimal treatment for patients at the time of discharge from hospitalization for an acute coronary syndrome, for comprehensive and safe care in the patient's transition between care from the acute event to the outpatient care, with the aim of optimizing the recovery of viable myocardium, guaranteeing the most appropriate secondary prevention, reducing the risk of a new coronary event and mortality, as well as the adequate reintegration of patients into daily life.

Los criterios diagnósticos, los tratamientos en el momento de la admisión y los fármacos utilizados en pacientes con síndrome coronario agudo están bien definidos en innumerables guías. Sin embargo, existe incertidumbre acerca de las medidas para recomendar durante la planificación del egreso de los pacientes. Este documento reúne las evidencias más recientes y el tratamiento estandarizado y óptimo para los pacientes al momento del egreso de una hospitalización por un síndrome coronario agudo, para un cuidado integral y seguro en la transición del paciente entre la atención del evento agudo y el cuidado ambulatorio, con el objetivo de optimizar la recuperación de miocardio viable, garantizar la prevención secundaria más adecuada, reducir el riesgo de un nuevo evento coronario y la mortalidad, así como la adecuada reinserción de los pacientes en la vida cotidiana.

Moderate physical activity is associated with lower depression, anxiety and stress in health-care workers during the COVID-19 pandemic.

OBJECTIVE: Health-care workers are in high risk for COVID-19 and may experience associated mental health disturbances. Although physical activity (PA) has positive effects on mental disturbances, it has not been fully investigated in health-team during COVID-19 pandemic. Therefore, we analyzed depression, anxiety and stress in health-care workers, and their relationship with PA before and during a COVID-19 peak. METHODS: Retrospective cohort study. PA (IPAQ short-form) evaluated and associated with depression, anxiety and stress (DAAS-21) at the beginning of COVID-19 first wave in Mexico (April 2020) in 1146 workers of a tertiary-care hospital, and in a subsequent occasion at the first wave peak (July-August/2020) in 311 workers (from the first ones). Data collected from routine surveillance. RESULTS: Depression increased 9%, anxiety 15%, and stress 10% at the pandemic peak. Subjects with higher frequency of baseline moderate PA showed lower severity of depression, anxiety and stress at the peak (p < 0.05). At the pandemic peak, female sex (OR = 2.42, 95%CI 1.14-5.13), diabetes (OR = 21.9, 95%CI 2.09-221) and baseline depression (OR = 8.86, 95%CI 4.30-18.2) predicted depression; baseline anxiety (OR = 5.52, 95%CI 3.01-10.1), working in COVID-19 area (OR = 4.14, 95%CI 1.99-8.64), and baseline moderate PA (OR = 0.35, 95%CI 0.16-0.73) predicted anxiety; and baseline stress (OR = 8.64, 95%CI 4.11-18.2), and moderate PA (OR = 0.35, 95%CI 0.15-0.82) predicted stress. CONCLUSION: Depression, stress, and particularly anxiety, increased in health-care workers from the beginning to the COVID-19 pandemic peak, and were predicted by the presence of the corresponding baseline mental alterations, and in the case of anxiety and stress, by the lower frequency of moderate PA.

Study of the Rv1417 and Rv2617c Membrane Proteins and Their Interactions with Nicotine Derivatives as Potential Inhibitors of Erp Virulence-Associated Factor in Mycobacterium tuberculosis: An In Silico Approach.

The increasing emergence of Mycobacterium tuberculosis (Mtb) strains resistant to traditional anti-tuberculosis drugs has alarmed health services worldwide. The search for new therapeutic targets and effective drugs that counteract the virulence and multiplication of Mtb represents a challenge for the scientific community. Several studies have considered the erp gene a possible therapeutic target in the last two decades, since its disruption negatively impacts Mtb multiplication. This gene encodes the exported repetitive protein (Erp), which is located in the cell wall of Mtb. In vitro studies have shown that the Erp protein interacts with two putative membrane proteins, Rv1417 and Rv2617c, and the impairment of their interactions can decrease Mtb replication. In this study, we present five nicotine analogs that can inhibit the formation of heterodimers and trimers between these proteins. Through DFT calculations, molecular dynamics, docking, and other advanced in silico techniques, we have analyzed the molecular complexes, and show the effect these compounds have on protein interactions. The results show that four of these analogs can be possible candidates to counteract the pathogenicity of Mtb. This study aims to combine research on the Erp protein as a therapeutic target in the search for new drugs that serve to create new therapies against tuberculosis disease.

Co-occurring pathogenic variants in 6q27 associated with dementia spectrum disorders in a Peruvian family.

Evidence suggests that there may be racial differences in risk factors associated with the development of Alzheimer's disease and related dementia (ADRD). We used whole-genome sequencing analysis and identified a novel combination of three pathogenic variants in the heterozygous state (UNC93A: rs7739897 and WDR27: rs61740334; rs3800544) in a Peruvian family with a strong clinical history of ADRD. Notably, the combination of these variants was present in two generations of affected individuals but absent in healthy members of the family. In silico and in vitro studies have provided insights into the pathogenicity of these variants. These studies predict that the loss of function of the mutant UNC93A and WDR27 proteins induced dramatic changes in the global transcriptomic signature of brain cells, including neurons, astrocytes, and especially pericytes and vascular smooth muscle cells, indicating that the combination of these three variants may affect the neurovascular unit. In addition, known key molecular pathways associated with dementia spectrum disorders were enriched in brain cells with low levels of UNC93A and WDR27. Our findings have thus identified a genetic risk factor for familial dementia in a Peruvian family with an Amerindian ancestral background.

Kinetics of the Glass Transition of Silica-Filled Styrene-Butadiene Rubber: The Effect of Resins.

Resins are important for enhancing both the processability and performance of rubber. Their efficient utilization requires knowledge about their influence on the dynamic glass transition and their miscibility behavior in the specific rubber compound. The resins investigated, poly-(α-methylstyrene) (AMS) and indene-coumarone (IC), differ in molecular rigidity but have a similar aromaticity degree and glass transition temperature. Transmission electron microscopy (TEM) investigations show an accumulation of IC around the silanized silica in styrene-butadiene rubber (SBR) at high contents, while AMS does not show this effect. This higher affinity between IC and the silica surface leads to an increased compactness of the filler network, as determined by dynamic mechanical analysis (DMA). The influence of the resin content on the glass transition of the rubber compounds is evaluated in the sense of the Gordon-Taylor equation and suggests a rigid amorphous fraction for the accumulated IC. Broadband dielectric spectroscopy (BDS) and fast differential scanning calorimetry (FDSC) are applied for the characterization of the dielectric and thermal relaxations as well as for the corresponding vitrification kinetics. The cooling rate dependence of the vitrification process is combined with the thermal and dielectric relaxation time by one single Vogel-Fulcher-Tammann-Hesse equation, showing an increased fragility of the rubber containing AMS.

Influence of the Polarity of the Plasticizer on the Mechanical Stability of the Filler Network by Simultaneous Mechanical and Dielectric Analysis.

Four styrene butadiene rubber (SBR) compounds were prepared to investigate the influence of the plasticizer polarity on the mechanical stability of the filler network using simultaneous mechanical and dielectric analysis. One compound was prepared without plasticizer and serves as a reference. The other three compounds were expanded with different plasticizers that have different polarities. Compared with an SBR sample without plasticizer, the conductivity of mechanically unloaded oil-extended SBR samples decreases by an order of magnitude. The polarity of the plasticizer shows hardly any influence because the plasticizers only affect the distribution of the filler clusters. Under static load, the dielectric properties seem to be oil-dependent. However, this behavior also results from the new distribution of the filler clusters caused by the mechanical damage and supported by the polarity grade of the plasticizer used. The Cole-Cole equation affirms these observations. The Cole-Cole relaxation time τ and thus, the position of maximal dielectric loss increases as the polarity of the plasticizer used is also increased. This, in turn, decreases the broadness parameter α implying a broader response function.

Novel In Silico Insights into Rv1417 and Rv2617c as Potential Protein Targets: The Importance of the Medium on the Structural Interactions with Exported Repetitive Protein (Erp) of Mycobacterium tuberculosis.

Nowadays, tuberculosis is the second leading cause of death from a monopathogenic transmitted disease, only ahead of COVID-19. The role of exported repetitive protein (Erp) in the virulence of Mycobacterium tuberculosis has been extensively demonstrated. In vitro and in vivo assays have identified that Erp interacts with Rv1417 and Rv2617c proteins, forming putative transient molecular complexes prior to localization to the cell envelope. Although new insights into the interactions and functions of Erp have emerged over the years, knowledge about its structure and protein-protein interactions at the atomistic level has not been sufficiently explored. In this work, we have combined several in silico methodologies to gain new insights into the structural relationship between these proteins. Two system conditions were evaluated by MD simulations: Rv1417 and Rv2617c embedded in a lipid membrane and another with a semi-polar solvent to mimic the electrostatic conditions on the membrane surface. The Erp protein was simulated as an unanchored structure. Stabilized structures were docked, and complexes were evaluated to recognize the main residues involved in protein-protein interactions. Our results show the influence of the medium on the structural conformation of proteins. Globular conformations were favored under high polarity conditions and showed a higher energetic affinity in complex formation. Meanwhile, disordered conformations were favored under semi-polar conditions and an increase in the number of contacts between residues was observed. In addition, the electrostatic potential analysis showed remarkable changes in protein interactions due to the polarity of the medium, demonstrating the relevance of Erp protein in heterodimer formation. On the other hand, contact analysis showed that several C-terminal residues of Erp were involved in the protein interactions, which seems to contradict experimental observations; however, these complexes could be transient forms. The findings presented in this work are intended to open new perspectives in the studies of Erp protein molecular interactions and to improve the knowledge about its function and role in the virulence of Mycobacterium tuberculosis.

Protocol to assess the effects of dysfunctional human vascular smooth muscle cells on other brain cells using in vitro models of Alzheimer's disease.

Here, we present a protocol to culture primary human vascular smooth muscle cells (VSMCs) under Alzheimer's disease (AD)-like conditions, including steps for morphological characterization with microscopy. We then describe functional assays, including wound healing, transwell, coculture, and supernatant assays, to evaluate the effect of dysfunctional VSMCs on the induction of the AD-associated microglial phenotype. Our approach can be applied to assess the effects of dysfunctional VSMCs on other cerebral cell lines including pericytes, astrocytes, and neurons under AD-like conditions in vitro. For complete details on the use and execution of this protocol, please refer to Aguilar-Pineda et al. (2021).

In Silico Analysis of the Antagonist Effect of Enoxaparin on the ApoE4-Amyloid-Beta (Aß) Complex at Different pH Conditions.

Apolipoprotein E4 (ApoE4) is thought to increase the risk of developing Alzheimer's disease. Several studies have shown that ApoE4-Amyloid ß (Aß) interactions can increment amyloid depositions in the brain and that this can be augmented at low pH values. On the other hand, experimental studies in transgenic mouse models have shown that treatment with enoxaparin significantly reduces cortical Aß levels, as well as decreases the number of activated astrocytes around Aß plaques. However, the interactions between enoxaparin and the ApoE4-Aß proteins have been poorly explored. In this work, we combine molecular dynamics simulations, molecular docking, and binding free energy calculations to elucidate the molecular properties of the ApoE4-Aß interactions and the competitive binding affinity of the enoxaparin on the ApoE4 binding sites. In addition, we investigated the effect of the environmental pH levels on those interactions. Our results showed that under different pH conditions, the closed form of the ApoE4 protein, in which the C-terminal domain folds into the protein, remains stabilized by a network of hydrogen bonds. This closed conformation allowed the generation of six different ApoE4-Aß interaction sites, which were energetically favorable. Systems at pH5 and 6 showed the highest energetic affinity. The enoxaparin molecule was found to have a strong energetic affinity for ApoE4-interacting sites and thus can neutralize or disrupt ApoE4-Aß complex formation.

Alzheimer's Disease: A Silent Pandemic - A Systematic Review on the Situation and Patent Landscape of the Diagnosis.

BACKGROUND: Alzheimer's disease (AD) is characterized by cognitive impairment, tau protein deposits, and amyloid beta plaques. AD impacted 44 million people in 2016, and it is estimated to affect 100 million people by 2050. AD is disregarded as a pandemic compared with other diseases. To date, there is no effective treatment or diagnosis. OBJECTIVE: We aimed to discuss the current tools used to diagnose COVID-19, point out their potential to be adapted for AD diagnosis, and review the landscape of existing patents in the AD field and future perspectives for AD diagnosis. METHODS: We carried out a scientific screening following a research strategy in PubMed; Web of Science; the Derwent Innovation Index; the KCI-Korean Journal Database; Sci- ELO; the Russian Science Citation index; and the CDerwent, EDerwent, and MDerwent index databases. RESULTS: A total of 326 from 6,446 articles about AD and 376 from 4,595 articles about COVID-19 were analyzed. Of these, AD patents were focused on biomarkers and neuroimaging with no accurate, validated diagnostic methods, and only 7% of kit development patents were found. In comparison, COVID-19 patents were 60% about kit development for diagnosis; they are highly accurate and are now commercialized. CONCLUSION: AD is still neglected and not recognized as a pandemic that affects the people and economies of all nations. There is a gap in the development of AD diagnostic tools that could be filled if the interest and effort that has been invested in tackling the COVID-19 emergency could also be applied for innovation.

Structural and Energetic Affinity of Annocatacin B with ND1 Subunit of the Human Mitochondrial Respiratory Complex I as a Potential Inhibitor: An In Silico Comparison Study with the Known Inhibitor Rotenone.

ND1 subunit possesses the majority of the inhibitor binding domain of the human mitochondrial respiratory complex I. This is an attractive target for the search for new inhibitors that seek mitochondrial dysfunction. It is known, from in vitro experiments, that some metabolites from Annona muricata called acetogenins have important biological activities, such as anticancer, antiparasitic, and insecticide. Previous studies propose an inhibitory activity of bovine mitochondrial respiratory complex I by bis-tetrahydrofurans acetogenins such as annocatacin B, however, there are few studies on its inhibitory effect on human mitochondrial respiratory complex I. In this work, we evaluate the in silico molecular and energetic affinity of the annocatacin B molecule with the human ND1 subunit in order to elucidate its potential capacity to be a good inhibitor of this subunit. For this purpose, quantum mechanical optimizations, molecular dynamics simulations and the molecular mechanics/Poisson-Boltzmann surface area (MM/PBSA) analysis were performed. As a control to compare our outcomes, the molecule rotenone, which is a known mitochondrial respiratory complex I inhibitor, was chosen. Our results show that annocatacin B has a greater affinity for the ND1 structure, its size and folding were probably the main characteristics that contributed to stabilize the molecular complex. Furthermore, the MM/PBSA calculations showed a 35% stronger binding free energy compared to the rotenone complex. Detailed analysis of the binding free energy shows that the aliphatic chains of annocatacin B play a key role in molecular coupling by distributing favorable interactions throughout the major part of the ND1 structure. These results are consistent with experimental studies that mention that acetogenins may be good inhibitors of the mitochondrial respiratory complex I.

CO2 Adsorption on PtCu Sub-Nanoclusters Deposited on Pyridinic N-Doped Graphene: A DFT Investigation.

To reduce the CO2 concentration in the atmosphere, its conversion to different value-added chemicals plays a very important role. Nevertheless, the stable nature of this molecule limits its conversion. Therefore, the design of highly efficient and selective catalysts for the conversion of CO2 to value-added chemicals is required. Hence, in this work, the CO2 adsorption on Pt4-xCux (x = 0-4) sub-nanoclusters deposited on pyridinic N-doped graphene (PNG) was studied using the density functional theory. First, the stability of Pt4-xCux (x = 0-4) sub-nanoclusters supported on PNG was analyzed. Subsequently, the CO2 adsorption on Pt4-xCux (x = 0-4) sub-nanoclusters deposited on PNG was computed. According to the binding energies of the Pt4-xCux (x = 0-4) sub-nanoclusters on PNG, it was observed that PNG is a good material to stabilize the Pt4-xCux (x = 0-4) sub-nanoclusters. In addition, charge transfer occurred from Pt4-xCux (x = 0-4) sub-nanoclusters to the PNG. When the CO2 molecule was adsorbed on the Pt4-xCux (x = 0-4) sub-nanoclusters supported on the PNG, the CO2 underwent a bond length elongation and variations in what bending angle is concerned. In addition, the charge transfer from Pt4-xCux (x = 0-4) sub-nanoclusters supported on PNG to the CO2 molecule was observed, which suggests the activation of the CO2 molecule. These results proved that Pt4-xCux (x = 0-4) sub-nanoclusters supported on PNG are adequate candidates for CO2 adsorption and activation.