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1.
Neural Netw ; 176: 106354, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38723308

RESUMEN

Neural operators, as a powerful approximation to the non-linear operators between infinite-dimensional function spaces, have proved to be promising in accelerating the solution of partial differential equations (PDE). However, it requires a large amount of simulated data, which can be costly to collect. This can be avoided by learning physics from the physics-constrained loss, which we refer to it as mean squared residual (MSR) loss constructed by the discretized PDE. We investigate the physical information in the MSR loss, which we called long-range entanglements, and identify the challenge that the neural network requires the capacity to model the long-range entanglements in the spatial domain of the PDE, whose patterns vary in different PDEs. To tackle the challenge, we propose LordNet, a tunable and efficient neural network for modeling various entanglements. Inspired by the traditional solvers, LordNet models the long-range entanglements with a series of matrix multiplications, which can be seen as the low-rank approximation to the general fully-connected layers and extracts the dominant pattern with reduced computational cost. The experiments on solving Poisson's equation and (2D and 3D) Navier-Stokes equation demonstrate that the long-range entanglements from the MSR loss can be well modeled by the LordNet, yielding better accuracy and generalization ability than other neural networks. The results show that the Lordnet can be 40× faster than traditional PDE solvers. In addition, LordNet outperforms other modern neural network architectures in accuracy and efficiency with the smallest parameter size.


Asunto(s)
Redes Neurales de la Computación , Simulación por Computador , Algoritmos , Dinámicas no Lineales
2.
Water Res ; 246: 120733, 2023 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-37879283

RESUMEN

Predicting water and energy consumption at high resolution over a short-term horizon is critical for water and energy resource management. Water and energy are shown to be closely interlinked in household consumption. However, hourly predictions are often based only on historical consumption data for the resource being predicted, with activity or appliance information and household attribution as additional information. Few studies have used aggregated water and energy consumption for predictions. Within this context, the current study proposed a novel hybrid machine learning model based on the Prophet time-series model, Gated Recurrent Unit network, and self-adaptive weights, called the Prophet-GRU model, which could jointly include historical water and electricity consumption as inputs for hourly water or electricity prediction. Data on hourly water and electricity consumption in six households in Beijing during January-March 2020 were used to train and validate the Prophet-GRU model. The goodness of fit indicator (R2) and prediction accuracy (mean squared error and mean absolute error) for the water and electricity predictions were evaluated. Compared with the single input of water or electricity, with the combined input of data of these two resources, the proposed Prophet-GRU model achieved improvements of 29.2 % and 48.5 % in R2, for water and electricity consumption prediction, respectively. Our results could help better understand water-energy linkages and promote collaborative water and energy management practices.


Asunto(s)
Aprendizaje Automático , Agua , Beijing
3.
Cereb Cortex ; 33(11): 6772-6784, 2023 05 24.
Artículo en Inglés | MEDLINE | ID: mdl-36734278

RESUMEN

Gaze change can misalign spatial reference frames encoding visual and vestibular signals in cortex, which may affect the heading discrimination. Here, by systematically manipulating the eye-in-head and head-on-body positions to change the gaze direction of subjects, the performance of heading discrimination was tested with visual, vestibular, and combined stimuli in a reaction-time task in which the reaction time is under the control of subjects. We found the gaze change induced substantial biases in perceived heading, increased the threshold of discrimination and reaction time of subjects in all stimulus conditions. For the visual stimulus, the gaze effects were induced by changing the eye-in-world position, and the perceived heading was biased in the opposite direction of gaze. In contrast, the vestibular gaze effects were induced by changing the eye-in-head position, and the perceived heading was biased in the same direction of gaze. Although the bias was reduced when the visual and vestibular stimuli were combined, integration of the 2 signals substantially deviated from predictions of an extended diffusion model that accumulates evidence optimally over time and across sensory modalities. These findings reveal diverse gaze effects on the heading discrimination and emphasize that the transformation of spatial reference frames may underlie the effects.


Asunto(s)
Percepción de Movimiento , Vestíbulo del Laberinto , Humanos , Tiempo de Reacción , Corteza Cerebral , Sesgo , Percepción Visual , Estimulación Luminosa
4.
Artículo en Inglés | MEDLINE | ID: mdl-29428736

RESUMEN

This article has been withdrawn at the request of the author(s) and/or editor. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/our-business/policies/article-withdrawal.

5.
Cell J ; 19(3): 469-475, 2017 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-28836409

RESUMEN

OBJECTIVES: Diabetic cardiomyopathy (DCM) is characterized as a coronary heart disease which expands during diabetes due to alterations in the myocardial function and structure. The currentstudy intends to elucidate the protective effect of gingerol on DCM in a streptozotocin (STZ)-induced diabetes mellitus (DM) rat model. MATERIALS AND METHODS: In this experimental study, the animals were divided into three groups: normal control, DM control, and DM+gingerol (10 mg/kg). The body weights of all rats were estimated at regular intervals. The myocardial profile, oxidative stress, and activities of metabolic enzymes were also scrutinized. The proinflammatory cytokine levels together with cellular protein expression connected with apoptosis were estimated via Western blot analysis. RESULTS: The rats that suffered from DCM exhibited abnormal levels of myocardial markers, aberrant metabolic enzymatic activity, elevated concentrations of inflammatory factors, and enhanced oxidative stress parameters along with increased cell death apoptosis. Whereas gingerol showed protective effects on the treated rats by an improved antioxidant defense system. CONCLUSIONS: The current findings suggested that gingerol is effective in the treatment of DCM by inhibition of inflammation and oxidative stress.

6.
Biomed Pharmacother ; 84: 1119-1125, 2016 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-27780141

RESUMEN

Glucocorticoids (GCs) play a vital role in the regulation of blood pressure by their permissive effects in potentiating vasoactive responses to catecholamines through glucocorticoid receptors. GCs achieve this function by controlling vascular smooth muscle tone. Clinically, low to moderate doses of GCs are generally used in the treatment of septic shock in recent years. GCs are now known to have both genomic and non-genomic effects. While genomic effects of GCs were well studied, few non-genomic effects were reported, much less the non-genomic mechanisms. One of the most important characters of their non-genomic effects is short latency. The aim of this study was to determine whether GCs can rapidly regulate blood pressure by their permissive action on norepinephrine (NE). Adrenalectomized rats were subjected to cecal ligation and puncture to induce septic shock. The septic rats displayed a significant decrease in the blood pressure response to NE. Dexamethasone (DEX) rapidly restores this hyporeactivity to NE in adrenalectomized septic rats. Further studies showed that DEX potentiates the NE-induced shrinkage and actin cytoskeleton rearrangement of single cell from mesenteric arteries in a short time. These findings suggest that GCs probably exert their permissive actions on the pressure response to NE through rapid non-genomic mechanisms. In this article, we found that as an adjunctive therapy for septic shock, the use of GCs may involve a rapid permissive action, and non-genomic effects of GCs may be involved in these processes.


Asunto(s)
Presión Sanguínea/efectos de los fármacos , Dexametasona/farmacología , Glucocorticoides/farmacología , Norepinefrina/farmacología , Choque Séptico/tratamiento farmacológico , Vasoconstrictores/farmacología , Citoesqueleto de Actina/efectos de los fármacos , Adrenalectomía , Animales , Ciego/microbiología , Ciego/cirugía , Células Cultivadas , Modelos Animales de Enfermedad , Ligadura , Masculino , Arterias Mesentéricas/efectos de los fármacos , Arterias Mesentéricas/fisiopatología , Músculo Liso Vascular/efectos de los fármacos , Músculo Liso Vascular/fisiopatología , Miocitos del Músculo Liso/efectos de los fármacos , Punciones , Ratas Sprague-Dawley , Choque Séptico/microbiología , Choque Séptico/fisiopatología , Factores de Tiempo , Vasoconstricción/efectos de los fármacos
7.
Mol Med Rep ; 7(2): 549-54, 2013 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-23174823

RESUMEN

The aim of the present study was to identify the rapid effect of dexamethasone (Dex) on norepinephrine (NE)­mediated contraction of vascular smooth muscle cells (VSMCs) and to establish the underlying mechanism(s). Rat VSMCs were preincubated with lipopolysaccharide to simulate acute septic shock. Myosin light chain (MLC20) phosphorylation of VSMCs was detected by western blot analysis to observe the effects of Dex on NE­mediated contraction. Activation of the RhoA/ RhoA kinase (ROCK), extracellular signal­regulated kinase (ERK) and p38 signaling pathways was detected by western blot analysis to explore the mechanism. It was identified that Dex rapidly promoted NE­induced phosphorylation of MLC20 in VSMCs and this effect may be non­genomic. The RhoA/ROCK, ERK and p38 pathways were demonstrated to be important for the rapid effect of Dex­induced promotion of NE­mediated contraction in VSMCs. The present results indicate that Dex may rapidly reverse the hyporeactivity of vasoconstriction to NE in vitro and this effect may be mediated by specific non­genomic mechanisms through increased activation of the RhoA/ROCK, ERK and p38 signaling pathways.


Asunto(s)
Antiinflamatorios/farmacología , Dexametasona/farmacología , Contracción Muscular/efectos de los fármacos , Norepinefrina/farmacología , Vasoconstrictores/farmacología , Animales , Línea Celular , Quinasas MAP Reguladas por Señal Extracelular/metabolismo , Músculo Liso Vascular/citología , Músculo Liso Vascular/metabolismo , Cadenas Ligeras de Miosina/metabolismo , Fosforilación , Proteína Fosfatasa 1/metabolismo , Ratas , Transducción de Señal/efectos de los fármacos , Proteínas Quinasas p38 Activadas por Mitógenos/metabolismo , Quinasas Asociadas a rho/metabolismo , Proteína de Unión al GTP rhoA/metabolismo
8.
Chin Med J (Engl) ; 124(19): 3127-32, 2011 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-22040567

RESUMEN

BACKGROUND: The immunomodulatory effects of glucocorticoids (GCs) have been described as bimodal. High concentration of GCs exerts immunosuppressive effects and low levels of GCs are immunopermissive. While the immunosuppressive mechanisms of GCs have been investigated intensely, the immunopermissive effects of GCs remain unclear. A lot of studies showed GCs could exert rapid non-genomic actions. We herein studied the rapid immunopromoting effects of GCs. METHODS: We observed the rapid (within 30 minutes) effects of corticosterone on respiratory burst of mouse peritoneal macrophages and studied their mechanisms. The superoxide anions were measured by cytochrome C reduction assay. Protein kinase C phosphorylation was measured by Western blotting and membrane fluidity was evaluated by fluorescence polarization measurement. RESULTS: The 10(-8) mol/L and 10(-7) mol/L corticosterone rapidly increased the superoxide anions production by macrophages, which were insensitive to GC-receptor antagonist, mifepristone, and protein-synthesis inhibitor, cycloheximide. Corticosterone coupled to bovine serum albumin was able to mimic the effects of corticosterone. The effects were independent of protein kinase C pathway and the change in membrane fluidity. CONCLUSIONS: The results indicate that corticosterone rapidly promote the superoxide anions production by mouse peritoneal macrophages may through non-genomic mechanisms. This study may contribute to understanding the effects of GCs under stress condition and the physiological significance of nongenomic effects of GCs.


Asunto(s)
Corticosterona/farmacología , Macrófagos Peritoneales/fisiología , Estallido Respiratorio/efectos de los fármacos , Animales , Macrófagos Peritoneales/efectos de los fármacos , Masculino , Ratones , Ratones Endogámicos BALB C , Superóxidos/metabolismo
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