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1.
Nature ; 626(8000): 799-807, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38326615

RESUMEN

Linking variants from genome-wide association studies (GWAS) to underlying mechanisms of disease remains a challenge1-3. For some diseases, a successful strategy has been to look for cases in which multiple GWAS loci contain genes that act in the same biological pathway1-6. However, our knowledge of which genes act in which pathways is incomplete, particularly for cell-type-specific pathways or understudied genes. Here we introduce a method to connect GWAS variants to functions. This method links variants to genes using epigenomics data, links genes to pathways de novo using Perturb-seq and integrates these data to identify convergence of GWAS loci onto pathways. We apply this approach to study the role of endothelial cells in genetic risk for coronary artery disease (CAD), and discover 43 CAD GWAS signals that converge on the cerebral cavernous malformation (CCM) signalling pathway. Two regulators of this pathway, CCM2 and TLNRD1, are each linked to a CAD risk variant, regulate other CAD risk genes and affect atheroprotective processes in endothelial cells. These results suggest a model whereby CAD risk is driven in part by the convergence of causal genes onto a particular transcriptional pathway in endothelial cells. They highlight shared genes between common and rare vascular diseases (CAD and CCM), and identify TLNRD1 as a new, previously uncharacterized member of the CCM signalling pathway. This approach will be widely useful for linking variants to functions for other common polygenic diseases.


Asunto(s)
Enfermedad de la Arteria Coronaria , Células Endoteliales , Estudio de Asociación del Genoma Completo , Hemangioma Cavernoso del Sistema Nervioso Central , Humanos , Enfermedad de la Arteria Coronaria/genética , Enfermedad de la Arteria Coronaria/patología , Células Endoteliales/metabolismo , Células Endoteliales/patología , Predisposición Genética a la Enfermedad/genética , Hemangioma Cavernoso del Sistema Nervioso Central/genética , Hemangioma Cavernoso del Sistema Nervioso Central/patología , Polimorfismo de Nucleótido Simple , Epigenómica , Transducción de Señal/genética , Herencia Multifactorial
2.
Nature ; 607(7917): 176-184, 2022 07.
Artículo en Inglés | MEDLINE | ID: mdl-35594906

RESUMEN

Gene regulation in the human genome is controlled by distal enhancers that activate specific nearby promoters1. A proposed model for this specificity is that promoters have sequence-encoded preferences for certain enhancers, for example, mediated by interacting sets of transcription factors or cofactors2. This 'biochemical compatibility' model has been supported by observations at individual human promoters and by genome-wide measurements in Drosophila3-9. However, the degree to which human enhancers and promoters are intrinsically compatible has not yet been systematically measured, and how their activities combine to control RNA expression remains unclear. Here we design a high-throughput reporter assay called enhancer × promoter self-transcribing active regulatory region sequencing (ExP STARR-seq) and applied it to examine the combinatorial compatibilities of 1,000 enhancer and 1,000 promoter sequences in human K562 cells. We identify simple rules for enhancer-promoter compatibility, whereby most enhancers activate all promoters by similar amounts, and intrinsic enhancer and promoter activities multiplicatively combine to determine RNA output (R2 = 0.82). In addition, two classes of enhancers and promoters show subtle preferential effects. Promoters of housekeeping genes contain built-in activating motifs for factors such as GABPA and YY1, which decrease the responsiveness of promoters to distal enhancers. Promoters of variably expressed genes lack these motifs and show stronger responsiveness to enhancers. Together, this systematic assessment of enhancer-promoter compatibility suggests a multiplicative model tuned by enhancer and promoter class to control gene transcription in the human genome.


Asunto(s)
Elementos de Facilitación Genéticos , Regiones Promotoras Genéticas , Elementos de Facilitación Genéticos/genética , Humanos , Regiones Promotoras Genéticas/genética , ARN/biosíntesis , ARN/genética , Factores de Transcripción/metabolismo
3.
Nature ; 595(7866): 309-314, 2021 07.
Artículo en Inglés | MEDLINE | ID: mdl-33953401

RESUMEN

Epigenetic dysregulation is a defining feature of tumorigenesis that is implicated in immune escape1,2. Here, to identify factors that modulate the immune sensitivity of cancer cells, we performed in vivo CRISPR-Cas9 screens targeting 936 chromatin regulators in mouse tumour models treated with immune checkpoint blockade. We identified the H3K9 methyltransferase SETDB1 and other members of the HUSH and KAP1 complexes as mediators of immune escape3-5. We also found that amplification of SETDB1 (1q21.3) in human tumours is associated with immune exclusion and resistance to immune checkpoint blockade. SETDB1 represses broad domains, primarily within the open genome compartment. These domains are enriched for transposable elements (TEs) and immune clusters associated with segmental duplication events, a central mechanism of genome evolution6. SETDB1 loss derepresses latent TE-derived regulatory elements, immunostimulatory genes, and TE-encoded retroviral antigens in these regions, and triggers TE-specific cytotoxic T cell responses in vivo. Our study establishes SETDB1 as an epigenetic checkpoint that suppresses tumour-intrinsic immunogenicity, and thus represents a candidate target for immunotherapy.


Asunto(s)
Silenciador del Gen , N-Metiltransferasa de Histona-Lisina/metabolismo , Neoplasias/genética , Neoplasias/inmunología , Animales , Antígenos Virales/inmunología , Sistemas CRISPR-Cas/genética , Cromatina/genética , Cromatina/metabolismo , Elementos Transponibles de ADN/genética , Modelos Animales de Enfermedad , Femenino , Antígenos de Histocompatibilidad Clase I/genética , Antígenos de Histocompatibilidad Clase I/inmunología , Humanos , Ratones , Neoplasias/tratamiento farmacológico , Receptor de Muerte Celular Programada 1/antagonistas & inhibidores , Linfocitos T Citotóxicos/citología , Linfocitos T Citotóxicos/inmunología
4.
Nature ; 593(7858): 238-243, 2021 05.
Artículo en Inglés | MEDLINE | ID: mdl-33828297

RESUMEN

Genome-wide association studies (GWAS) have identified thousands of noncoding loci that are associated with human diseases and complex traits, each of which could reveal insights into the mechanisms of disease1. Many of the underlying causal variants may affect enhancers2,3, but we lack accurate maps of enhancers and their target genes to interpret such variants. We recently developed the activity-by-contact (ABC) model to predict which enhancers regulate which genes and validated the model using CRISPR perturbations in several cell types4. Here we apply this ABC model to create enhancer-gene maps in 131 human cell types and tissues, and use these maps to interpret the functions of GWAS variants. Across 72 diseases and complex traits, ABC links 5,036 GWAS signals to 2,249 unique genes, including a class of 577 genes that appear to influence multiple phenotypes through variants in enhancers that act in different cell types. In inflammatory bowel disease (IBD), causal variants are enriched in predicted enhancers by more than 20-fold in particular cell types such as dendritic cells, and ABC achieves higher precision than other regulatory methods at connecting noncoding variants to target genes. These variant-to-function maps reveal an enhancer that contains an IBD risk variant and that regulates the expression of PPIF to alter the membrane potential of mitochondria in macrophages. Our study reveals principles of genome regulation, identifies genes that affect IBD and provides a resource and generalizable strategy to connect risk variants of common diseases to their molecular and cellular functions.


Asunto(s)
Elementos de Facilitación Genéticos/genética , Predisposición Genética a la Enfermedad , Variación Genética/genética , Genoma Humano/genética , Estudio de Asociación del Genoma Completo , Enfermedades Inflamatorias del Intestino/genética , Línea Celular , Cromosomas Humanos Par 10/genética , Ciclofilinas/genética , Células Dendríticas , Femenino , Humanos , Macrófagos/metabolismo , Masculino , Mitocondrias/metabolismo , Especificidad de Órganos/genética , Fenotipo
5.
Genes Dev ; 33(11-12): 669-683, 2019 06 01.
Artículo en Inglés | MEDLINE | ID: mdl-30975723

RESUMEN

The transcriptional repression of alternative lineage genes is critical for cell fate commitment. Mechanisms by which locus-specific gene silencing is initiated and heritably maintained during cell division are not clearly understood. To study the maintenance of silent gene states, we investigated how the Cd4 gene is stably repressed in CD8+ T cells. Through CRISPR and shRNA screening, we identified the histone chaperone CAF-1 as a critical component for Cd4 repression. We found that the large subunit of CAF-1, Chaf1a, requires the N-terminal KER domain to associate with the histone deacetylases HDAC1/2 and the histone demethylase LSD1, enzymes that also participate in Cd4 silencing. When CAF-1 was lacking, Cd4 derepression was markedly enhanced in the absence of the de novo DNA methyltransferase Dnmt3a but not the maintenance DNA methyltransferase Dnmt1. In contrast to Dnmt1, Dnmt3a deficiency did not significantly alter levels of DNA methylation at the Cd4 locus. Instead, Dnmt3a deficiency sensitized CD8+ T cells to Cd4 derepression mediated by compromised functions of histone-modifying factors, including the enzymes associated with CAF-1. Thus, we propose that the heritable silencing of the Cd4 gene in CD8+ T cells exploits cooperative functions among the DNA methyltransferases, CAF-1, and histone-modifying enzymes.


Asunto(s)
Antígenos CD4/genética , Factor 1 de Ensamblaje de la Cromatina/metabolismo , ADN (Citosina-5-)-Metiltransferasas/metabolismo , Proteína 4 de Unión a Retinoblastoma/metabolismo , Linfocitos T Citotóxicos/inmunología , Linfocitos T Citotóxicos/metabolismo , Animales , Antígenos CD4/metabolismo , ADN (Citosina-5-)-Metiltransferasa 1/genética , ADN (Citosina-5-)-Metiltransferasa 1/metabolismo , ADN (Citosina-5-)-Metiltransferasas/genética , ADN Metiltransferasa 3A , Femenino , Regulación de la Expresión Génica , Silenciador del Gen , Chaperonas de Histonas/metabolismo , Histona Desacetilasas/metabolismo , Histonas/metabolismo , Masculino , Ratones , Dominios Proteicos
6.
Eur Heart J ; 45(3): 181-194, 2024 Jan 14.
Artículo en Inglés | MEDLINE | ID: mdl-37634192

RESUMEN

BACKGROUND AND AIMS: Coronary flow capacity (CFC) is associated with an observed 10-year survival probability for individual patients before and after actual revascularization for comparison to virtual hypothetical ideal complete revascularization. METHODS: Stress myocardial perfusion (mL/min/g) and coronary flow reserve (CFR) per pixel were quantified in 6979 coronary artery disease (CAD) subjects using Rb-82 positron emission tomography (PET) for CFC maps of artery-specific size-severity abnormalities expressed as percent left ventricle with prospective follow-up to define survival probability per-decade as fraction of 1.0. RESULTS: Severely reduced CFC in 6979 subjects predicted low survival probability that improved by 42% after revascularization compared with no revascularization for comparable severity (P = .0015). For 283 pre-and-post-procedure PET pairs, severely reduced regional CFC-associated survival probability improved heterogeneously after revascularization (P < .001), more so after bypass surgery than percutaneous coronary interventions (P < .001) but normalized in only 5.7%; non-severe baseline CFC or survival probability did not improve compared with severe CFC (P = .00001). Observed CFC-associated survival probability after actual revascularization was lower than virtual ideal hypothetical complete post-revascularization survival probability due to residual CAD or failed revascularization (P < .001) unrelated to gender or microvascular dysfunction. Severely reduced CFC in 2552 post-revascularization subjects associated with low survival probability also improved after repeat revascularization compared with no repeat procedures (P = .025). CONCLUSIONS: Severely reduced CFC and associated observed survival probability improved after first and repeat revascularization compared with no revascularization for comparable CFC severity. Non-severe CFC showed no benefit. Discordance between observed actual and virtual hypothetical post-revascularization survival probability revealed residual CAD or failed revascularization.


Asunto(s)
Enfermedad de la Arteria Coronaria , Humanos , Radioisótopos de Rubidio , Estudios Prospectivos , Tomografía de Emisión de Positrones/métodos , Angiografía Coronaria/métodos
7.
J Org Chem ; 89(5): 3202-3210, 2024 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-38329896

RESUMEN

We report a method for using elemental sulfur to facilitate the cyclization of aryl hydrazones and aryl isothiocyanates, affording biorelated 2-imino-1,3,4-thiadiazoles. Reactions progressed in the presence of elemental sulfur, N-methylmorpholine base, and DMSO solvent, while were tolerant of a wide range of functionalities including halogen, nitro, cyano, methylsulfonyl, and heterocyclic groups. The method appears to offer a general pathway for using simple, cheap, and stable reagents to afford triaryl-substituted 2-imino-1,3,4-thiadiazoles under relatively mild conditions.

8.
Org Biomol Chem ; 22(26): 5296-5300, 2024 Jul 03.
Artículo en Inglés | MEDLINE | ID: mdl-38896038

RESUMEN

The synthesis of medicinally relevant N-aryl-substituted 2-aminobenzothiazoles often uses 2-aminothiophenol derivatives, which are not commercially abundant, as starting materials. Herein, we report a method for the annulation of C3-substituted nitroarenes and aryl isothiocyanates towards the synthesis of 2-aminobenzothiazoles. Reactions proceeded in the presence of cobalt ferrite nanoparticles as a catalyst, DABCO as a base, and DMF as a promoter. The cobalt ferrite nanoparticles could be recovered after each run and reused up to 3 times while the product yield was not diminished. Our method appears to be the first example of the direct use of substituted nitroarenes for yielding 2-aminobenzothiazoles.

9.
Org Biomol Chem ; 22(6): 1234-1244, 2024 Feb 07.
Artículo en Inglés | MEDLINE | ID: mdl-38240351

RESUMEN

Herein we report a method for affording 2-benzyl benzoxazoles from substituted styrenes and 2-nitrophenols. The success of this method relies on the use of simple reagents, namely elemental sulfur and DABCO. A combination of identical reagents was utilized for the annulation of styrenes with N,N-dialkyl-3-nitroanilines to afford 2-benzyl benzothiazoles. Overall, benzoxazoles and benzothiazoles bearing useful functionalities such as halogens, amines, and heterocyclic groups were isolated in moderate to good yields. Our methods are a rare example of divergent transformations of substituted nitroarenes towards 2-benzyl benzoxazoles and benzothiazoles.

10.
J Math Biol ; 88(3): 36, 2024 03 01.
Artículo en Inglés | MEDLINE | ID: mdl-38429564

RESUMEN

Biochemical covalent modification networks exhibit a remarkable suite of steady state and dynamical properties such as multistationarity, oscillations, ultrasensitivity and absolute concentration robustness. This paper focuses on conditions required for a network of this type to have a species with absolute concentration robustness. We find that the robustness in a substrate is endowed by its interaction with a bifunctional enzyme, which is an enzyme that has different roles when isolated versus when bound as a substrate-enzyme complex. When isolated, the bifunctional enzyme promotes production of more molecules of the robust species while when bound, the same enzyme facilitates degradation of the robust species. These dual actions produce robustness in the large class of covalent modification networks. For each network of this type, we find the network conditions for the presence of robustness, the species that has robustness, and its robustness value. The unified approach of simultaneously analyzing a large class of networks for a single property, i.e. absolute concentration robustness, reveals the underlying mechanism of the action of bifunctional enzyme while simultaneously providing a precise mathematical description of bifunctionality.

11.
Nucleic Acids Res ; 50(W1): W108-W114, 2022 07 05.
Artículo en Inglés | MEDLINE | ID: mdl-35524558

RESUMEN

Computational models have great potential to accelerate bioscience, bioengineering, and medicine. However, it remains challenging to reproduce and reuse simulations, in part, because the numerous formats and methods for simulating various subsystems and scales remain siloed by different software tools. For example, each tool must be executed through a distinct interface. To help investigators find and use simulation tools, we developed BioSimulators (https://biosimulators.org), a central registry of the capabilities of simulation tools and consistent Python, command-line and containerized interfaces to each version of each tool. The foundation of BioSimulators is standards, such as CellML, SBML, SED-ML and the COMBINE archive format, and validation tools for simulation projects and simulation tools that ensure these standards are used consistently. To help modelers find tools for particular projects, we have also used the registry to develop recommendation services. We anticipate that BioSimulators will help modelers exchange, reproduce, and combine simulations.


Asunto(s)
Simulación por Computador , Programas Informáticos , Humanos , Bioingeniería , Modelos Biológicos , Sistema de Registros , Investigadores
12.
Molecules ; 29(8)2024 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-38675609

RESUMEN

This first study investigated the presence of dioxins and furans in river sediments around a craft village in Vietnam, focusing on Secondary Steel Recycling. Sediment samples were collected from various locations along the riverbed near the Da Hoi Secondary Steel Recycling village in Bac Ninh province. The analysis was conducted using a HRGC/HRMS-DFS device, detecting a total of 17 dioxin/furan isomers in all samples, with an average total concentration of 288.86 ng/kg d.w. The concentrations of dioxin/furan congeners showed minimal variation among sediment samples, ranging from 253.9 to 344.2 ng/kg d.w. The predominant compounds in the dioxin group were OCDD, while in the furan group, they were 1,2,3,4,6,7,8-HpCDF and OCDF. The chlorine content in the molecule appeared to be closely related to the concentration of dioxins and their percentage distribution. However, the levels of furan isomers did not vary significantly. The distribution of these compounds was not dependent on the flow direction, as they were mainly found in solid waste and are not water-soluble. Although the hepta and octa congeners had high concentrations, when converted to TEQ values, the tetra and penta groups (for dioxins) and the penta and hexa groups (for furans) contributed more to toxicity. Furthermore, the source of dioxins in sediments at Da Hoi does not only originate from steel recycling production activities but also from other combustion sites. The average total toxicity was 10.92 ng TEQ/kg d.w, ranging from 4.99 to 17.88 ng TEQ/kg d.w, which did not exceed the threshold specified in QCVN 43:2017/BTNMT, the National Technical Regulation on Sediment Quality. Nonetheless, these levels are still concerning. The presence of these toxic substances not only impacts aquatic organisms in the sampled water environment but also poses potential health risks to residents living nearby.


Asunto(s)
Dioxinas , Monitoreo del Ambiente , Furanos , Sedimentos Geológicos , Ríos , Acero , Contaminantes Químicos del Agua , Ríos/química , Vietnam , Sedimentos Geológicos/química , Sedimentos Geológicos/análisis , Dioxinas/análisis , Acero/química , Contaminantes Químicos del Agua/análisis , Furanos/análisis , Furanos/química , Monitoreo del Ambiente/métodos , Reciclaje
13.
Environ Res ; 225: 115516, 2023 05 15.
Artículo en Inglés | MEDLINE | ID: mdl-36805897

RESUMEN

Tetracycline (TCC) and sulfadiazine (SDZ) are two of the most consumed antibiotics for human therapies and bacterial infection treatments in aquafarming fields, but their accumulative residues can result in negative effects on water and aquatic microorganisms. Removal techniques are therefore required to purify water before use. Herein, we concentrate on adsorptive removal of TCC and SDZ using cobalt@carbon nanotubes (Co@CNTs) derived from Co-ZIF-67. The presence of CNTs on the edge of nanocomposites was observed. Taguchi orthogonal array was designed with four variables including initial concentration (5-20 mg L-1), dosage (0.05-0.2 g L-1), time (60-240 min), and pH (2-10). Concentration and pH were found to be main contributors to adsorption of tetracycline and sulfadiazine, respectively. The optimum condition was found at concentration 5 mg L-1, dosage 0.2 g L-1, contact time 240 min, and pH 7 for both TCC and SDZ removals. Confirmation tests showed that Co@CNTs-700 removed 99.6% of TCC and 97.3% of SDZ with small errors (3-5.5%). Moreover, the kinetic and isotherm were studied, which kinetic and isotherm data were best fitted with pseudo second-order model and Langmuir. Maximum adsorption capacity values for TCC and SDZ were determined at 118.4-174.1 mg g-1 for 180 min. We also proposed the main role of interactions such as hydrogen bonding, π-π stacking, and electrostatic attraction in the adsorption of antibiotics. With high adsorption performance, Co@CNTs-700 is expected to remove antibiotics efficiently from wastewater.


Asunto(s)
Nanocompuestos , Nanotubos de Carbono , Contaminantes Químicos del Agua , Humanos , Antibacterianos , Sulfadiazina , Nanotubos de Carbono/química , Tetraciclina , Agua , Nanocompuestos/química , Adsorción , Contaminantes Químicos del Agua/análisis , Cinética , Concentración de Iones de Hidrógeno
14.
Environ Res ; 216(Pt 1): 114422, 2023 01 01.
Artículo en Inglés | MEDLINE | ID: mdl-36162476

RESUMEN

Nowadays, emerging hazardous pollutants have caused many harmful effects on the environment and human health, calling for the state of the art methods for detection, qualification, and treatment. Metal-organic frameworks are porous, flexible, and versatile materials with unique structural properties, which can solve such problems. In this work, we reviewed the synthesis, activation, and characterization, and potential applications of NH2-MIL-53(Al). This material exhibited intriguing breathing effects, and obtained very high surface areas (182.3-1934 m2/g) with diverse morphologies. More importantly, NH2-MIL-53(Al) based materials could be used for the detection and removal of various toxic pollutants such as organic dyes, pharmaceuticals, herbicides, insecticides, phenols, heavy metals, and fluorides. We shed light on plausible adsorption mechanisms such as hydrogen bonds, π-π stacking interactions, and electrostatic interactions onto NH2-MIL-53(Al) adsorbents. Interestingly, NH2-MIL-53(Al) based adsorbents could be recycled for many cycles with high stability. This review also recommended that NH2-MIL-53(Al) based materials can be a good platform for the environmental remediation fields.


Asunto(s)
Contaminantes Ambientales , Estructuras Metalorgánicas , Humanos , Adsorción
15.
J Math Biol ; 87(4): 62, 2023 09 22.
Artículo en Inglés | MEDLINE | ID: mdl-37736867

RESUMEN

Our earlier work in Nguyen et al. (Maximizing metapopulation growth rate and biomass in stream networks. arXiv preprint arXiv:2306.05555 , 2023) shows that concentrating resources on the upstream end tends to maximize the total biomass in a metapopulation model for a stream species. In this paper, we continue our research direction by further considering a Lotka-Volterra competition patch model for two stream species. We show that the species whose resource allocations maximize the total biomass has the competitive advantage.


Asunto(s)
Asignación de Recursos , Biomasa
16.
Ann Intern Med ; 175(4): 574-589, 2022 04.
Artículo en Inglés | MEDLINE | ID: mdl-34978851

RESUMEN

Asian Americans (AsA), Native Hawaiians, and Pacific Islanders (NHPI) comprise 7.7% of the U.S. population, and AsA have had the fastest growth rate since 2010. Yet the National Institutes of Health (NIH) has invested only 0.17% of its budget on AsA and NHPI research between 1992 and 2018. More than 40 ethnic subgroups are included within AsA and NHPI (with no majority subpopulation), which are highly diverse culturally, demographically, linguistically, and socioeconomically. However, data for these groups are often aggregated, masking critical health disparities and their drivers. To address these issues, in March 2021, the National Heart, Lung, and Blood Institute, in partnership with 8 other NIH institutes, convened a multidisciplinary workshop to review current research, knowledge gaps, opportunities, barriers, and approaches for prevention research for AsA and NHPI populations. The workshop covered 5 domains: 1) sociocultural, environmental, psychological health, and lifestyle dimensions; 2) metabolic disorders; 3) cardiovascular and lung diseases; 4) cancer; and 5) cognitive function and healthy aging. Two recurring themes emerged: Very limited data on the epidemiology, risk factors, and outcomes for most conditions are available, and most existing data are not disaggregated by subgroup, masking variation in risk factors, disease occurrence, and trajectories. Leveraging the vast phenotypic differences among AsA and NHPI groups was identified as a key opportunity to yield novel clues into etiologic and prognostic factors to inform prevention efforts and intervention strategies. Promising approaches for future research include developing collaborations with community partners, investing in infrastructure support for cohort studies, enhancing existing data sources to enable data disaggregation, and incorporating novel technology for objective measurement. Research on AsA and NHPI subgroups is urgently needed to eliminate disparities and promote health equity in these populations.


Asunto(s)
Asiático , Nativos de Hawái y Otras Islas del Pacífico , Hawaii , Promoción de la Salud , Humanos , National Institutes of Health (U.S.) , Estados Unidos/epidemiología
17.
Chaos ; 33(10)2023 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-37844292

RESUMEN

Networks with different levels of interactions, including multilayer and multiplex networks, can display a rich diversity of dynamical behaviors and can be used to model and study a wide range of systems. Despite numerous efforts to investigate these networks, obtaining mathematical descriptions for the dynamics of multilayer and multiplex systems is still an open problem. Here, we combine ideas and concepts from linear algebra and graph theory with nonlinear dynamics to offer a novel approach to study multiplex networks of Kuramoto oscillators. Our approach allows us to study the dynamics of a large, multiplex network by decomposing it into two smaller systems: one representing the connection scheme within layers (intra-layer), and the other representing the connections between layers (inter-layer). Particularly, we use this approach to compose solutions for multiplex networks of Kuramoto oscillators. These solutions are given by a combination of solutions for the smaller systems given by the intra- and inter-layer systems, and in addition, our approach allows us to study the linear stability of these solutions.

18.
Sensors (Basel) ; 23(17)2023 Aug 29.
Artículo en Inglés | MEDLINE | ID: mdl-37687959

RESUMEN

The maximum power point tracking (MPPT) solutions improve power generation efficiency, quickly stabilizing the output waveform of photovoltaic (PV) systems under variable operating conditions. Along with new algorithms, improved and adjusted methods to exploit energy from PV systems are increasingly being researched and proposed. However, the proposed solutions based on the traditional algorithms and their improvements have poor performance, while the advanced algorithms or hybrid methods bring high performance but need to be simplified, and the response speed is higher. Moreover, a suitable PV configuration makes choosing a simple but highly efficient algorithm, especially in low-power PV system applications such as rooftop solar power, traffic lights, and moving vehicles…where the number of PV panels is insufficient to implement flexible configurations. This paper proposes a modified version of the Perturb and Observe (MPO) algorithm to improve MPPT performance and increase convergence speed in the parallel structure of PV panels. The Short-Circuit Current (Isc) and Open-Circuit Voltage (Voc) are calculated directly at specific operating conditions to quickly determine the potential maximum power point (MPP) that will reduce power interruptions and increase power generation efficiency compared to periodic updates. Therefore, the proposed solution converges faster, with higher efficiency, and the output signal in static and dynamic MPPT situations is more stable. The results show that the highest efficiency in simulation and experiment is 99.99% and 99.93%, respectively, while the convergence speed is 0.01 s and 0.03 s, respectively. They are better than the traditional Perturb and Observe (P&O) algorithm, the Variable Step Size Perturb and Observe (VSSP&O) method, and the Particle Swarm Optimization (PSO) technique under the same operating conditions. In addition, its performance and convergence speed are also compared with the latest introduced algorithms. The results show that it is valuable and reliable for parallel PV configuration.

19.
Dent Traumatol ; 39 Suppl 1: 63-69, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-37060204

RESUMEN

BACKGROUND/AIM: The clinical management of growing patients with missing teeth in the anterior maxilla can be challenging due to limited treatment options and high esthetic demands. Tooth autotransplantation (AT) is a viable option for these cases. The selection of donor teeth has been reported to be driven by root development, existing malocclusion, and esthetics. The aim of this study was to add to the evidence base of tooth selection criteria for AT by examining candidate donor teeth root width and crown-root angles, two factors arguably important for surgical planning and esthetics. MATERIAL AND METHODS: Cementoenamel junction (CEJ) tooth width and crown-root angle measurements were made using cone-beam computed tomography (CBCT) images of 30 children and adolescents of European descent (mean age = 13 years, range = 10-17 years; 63% male) from a private orthodontic practice. Measurements of maxillary central and lateral incisors (index teeth) were compared with measurements of maxillary second premolars, mandibular central incisors, and mandibular first and second premolars (candidate donor teeth). Analyses relied on descriptive statistics of mean within-subject differences between index and donor teeth and the proportion of individuals without clinically important differences (i.e., >1.5 mm width deficit and > 15 degrees crown-root angle difference). RESULTS: Mandibular first premolars were the most compatible teeth for the replacement of maxillary central incisors based on both width (≥97% of individuals) and angle measurements (≥87% of individuals), followed closely by mandibular second premolars. Mandibular central incisors were the most compatible for the replacement of maxillary laterals, among all individuals based on width and ≥ 90% based on angle, whereas mandibular first premolars were somewhat less compatible. CONCLUSIONS: The study offers evidence of within-person, CBCT-based root width dimension and crown-root angle compatibilities. This information can be considered in addition to existing tooth selection criteria for AT including Angle's classification, midline deviation, crowding severity, root development, and esthetics.


Asunto(s)
Maloclusión , Tomografía Computarizada de Haz Cónico Espiral , Adolescente , Niño , Humanos , Masculino , Femenino , Maxilar/diagnóstico por imagen , Trasplante Autólogo , Coronas , Incisivo/diagnóstico por imagen , Raíz del Diente/diagnóstico por imagen , Tomografía Computarizada de Haz Cónico/métodos
20.
J Biol Chem ; 297(5): 101311, 2021 11.
Artículo en Inglés | MEDLINE | ID: mdl-34666041

RESUMEN

Carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) is expressed in the liver and secreted as biliary glycoprotein 1 (BGP1) via bile canaliculi (BCs). CEACAM1-LF is a 72 amino acid cytoplasmic domain mRNA splice isoform with two immunoreceptor tyrosine-based inhibitory motifs (ITIMs). Ceacam1-/- or Ser503Ala transgenic mice have been shown to develop insulin resistance and nonalcoholic fatty liver disease; however, the role of the human equivalent residue, Ser508, in lipid dysregulation is unknown. Human HepG2 hepatocytes that express CEACAM1 and form BC in vitro were compared with CEACAM1-/- cells and CEACAM1-/- cells expressing Ser508Ala null or Ser508Asp phosphorylation mimic mutations or to phosphorylation null mutations in the tyrosine ITIMs known to be phosphorylated by the tyrosine kinase Src. CEACAM1-/- cells and the Ser508Asp and Tyr520Phe mutants strongly retained lipids, while Ser508Ala and Tyr493Phe mutants had low lipid levels compared with wild-type cells, indicating that the ITIM mutants phenocopied the Ser508 mutants. We found that the fatty acid transporter CD36 was upregulated in the S508A mutant, coexpressed in BCs with CEACAM1, co-IPed with CEACAM1 and Src, and when downregulated via RNAi, an increase in lipid droplet content was observed. Nuclear translocation of CD36 associated kinase LKB1 was increased sevenfold in the S508A mutant versus CEACAM1-/- cells and correlated with increased activation of CD36-associated kinase AMPK in CEACAM1-/- cells. Thus, while CEACAM1-/- HepG2 cells upregulate lipid storage similar to Ceacam1-/- in murine liver, the null mutation Ser508Ala led to decreased lipid storage, emphasizing evolutionary changes between the CEACAM1 genes in mouse and humans.


Asunto(s)
Antígenos CD/metabolismo , Antígenos CD36/metabolismo , Antígeno Carcinoembrionario/metabolismo , Moléculas de Adhesión Celular/metabolismo , Metabolismo de los Lípidos , Animales , Antígenos CD/genética , Antígenos CD36/genética , Antígeno Carcinoembrionario/genética , Moléculas de Adhesión Celular/genética , Células Hep G2 , Humanos , Ratones , Ratones Noqueados , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo
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