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1.
Angew Chem Int Ed Engl ; 63(23): e202404763, 2024 Jun 03.
Artículo en Inglés | MEDLINE | ID: mdl-38588210

RESUMEN

The electrochemical CO2 reduction reaction (eCO2RR) to multicarbon products has been widely recognized for Cu-based catalysts. However, the structural changes in Cu-based catalysts during the eCO2RR pose challenges to achieving an in-depth understanding of the structure-activity relationship, thereby limiting catalyst development. Herein, we employ constant-potential density functional theory calculations to investigate the sintering process of Cu single atoms of Cu-N-C single-atom catalysts into clusters under eCO2RR conditions. Systematic constant-potential ab initio molecular dynamics simulations revealed that the leaching of Cu-(CO)x moieties and subsequent agglomeration into clusters can be facilitated by synergistic adsorption of H and eCO2RR intermediates (e.g., CO). Increasing the Cu2+ concentration or the applied potential can efficiently suppress Cu sintering. Both microkinetic simulations and experimental results further confirm that sintered Cu clusters play a crucial role in generating C2 products. These findings provide significant insights into the dynamic evolution of Cu-based catalysts and the origin of their activity toward C2 products during the eCO2RR.

2.
J Assist Reprod Genet ; 41(4): 875-883, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38366240

RESUMEN

PURPOSE: This study investigated the safety and effectiveness of oocyte vitrification by comparing the clinical pregnancy and perinatal outcomes between transfer cycles of vitrified oocytes and those of vitrified embryos. METHODS: A retrospective cohort study was conducted to analyze the clinical data of patients who underwent cleavage-stage embryo transfer at the Department of Reproductive Medicine between January 2011 and June 2021. Seventy-seven transfer cycles of fresh cleavage-stage embryos developed from vitrified-thawed oocytes (oocyte vitrification group) and 2170 transfer cycles of vitrified-thawed cleavage-stage embryos developed from fresh oocytes (embryo vitrification group) were included. Further, 293 cases were selected from the embryo vitrification group after applying propensity score matching at 1:4. The primary outcomes were miscarriage rate, live birth rate, and neonatal birth weight. RESULTS: No statistically significant differences were observed in the baseline data, pregnancy, perinatal outcomes, or neonatal outcomes for either singleton or twin births between the two groups after matching. Backwards stepwise regression was used to analyze the length of gestation. The age of female participants (ß = - 0.410, 95% CI = - 1.339 ~ - 0.620, P < 0.001) had a statistically significant effect. CONCLUSION: Oocyte vitrification results in similar clinical pregnancy and perinatal outcomes as does embryo vitrification; hence, it is a relatively safe assisted reproductive technique.


Asunto(s)
Criopreservación , Transferencia de Embrión , Oocitos , Resultado del Embarazo , Índice de Embarazo , Puntaje de Propensión , Vitrificación , Humanos , Femenino , Embarazo , Oocitos/crecimiento & desarrollo , Criopreservación/métodos , Transferencia de Embrión/métodos , Adulto , Estudios Retrospectivos , Fertilización In Vitro/métodos , Nacimiento Vivo/epidemiología , Aborto Espontáneo/epidemiología , Tasa de Natalidad , Recién Nacido
3.
Small ; 20(15): e2306809, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38009781

RESUMEN

The diagnosis and evaluation of traumatic brain injury (TBI) are crucial steps toward the treatment and prognosis of patients. A common question remains as to whether it is possible to introduce an ideal device for signal detection and evaluation that can directly connect digital signals with TBI, thereby enabling prompt response of the evaluation signal and sensitive and specific functioning of the detection process. Herein, a method is presented utilizing polymetric porous membranes with TRTK-12 peptide-modified nanochannels for the detection of S100B (a TBI biomarker) and assessment of TBI severity. The method leverages the specific bonding force between TRTK-12 peptide and S100B protein, along with the nanoconfinement effect of nanochannels, to achieve high sensitivity (LOD: 0.002 ng mL-1) and specificity (∆I/I0: 44.7%), utilizing ionic current change as an indicator. The proposed method, which is both sensitive and specific, offers a simple yet responsive approach for real-time evaluation of TBI severity. This innovative technique provides valuable scientific insights into the advancement of future diagnostic and therapeutic integration devices.


Asunto(s)
Biomimética , Lesiones Traumáticas del Encéfalo , Humanos , Péptidos , Lesiones Traumáticas del Encéfalo/diagnóstico , Pronóstico , Biomarcadores , Subunidad beta de la Proteína de Unión al Calcio S100
4.
BMC Med Genomics ; 16(1): 273, 2023 11 01.
Artículo en Inglés | MEDLINE | ID: mdl-37915045

RESUMEN

OBJECTIVE: To determine the effect of different translocation characteristics on fertilization rate and blastocyst development in chromosomal translocation patients. METHODS: This retrospective cohort study was conducted at the Third Affiliated Hospital of Zhengzhou University From January 2017 to December 2022.All couples were diagnosed as reciprocal translocation or Robertsonian translocation by karyotype of peripheral blood lymphocytes test. After adjusting for confounding factors, the effect of chromosomal rearrangement characteristics, such as carrier sex, translocation type, chromosome length and break sites, on fertilization rate and embryo development were analysed separately using multiple linear regression. RESULTS: In cases of Robertsonian translocation (RobT), the carrier sex plays an independent role in fertilization rate, and the male carriers was lower than that of female carriers (76.16% vs.86.26%, P = 0.009). In reciprocal translocation (RecT), the carrier sex, chromosome types and break sites had no influence on fertilization rate, blastocyst formation rate (P > 0.05). However, patients with human longer chromosomal (chromosomes 1-5) translocation have a lower available blastocyst formation rate (Group AB vs. Group CD: 41.49%vs.46.01%, P = 0.027). For male carriers, the translocation types was an independent factor affecting the fertilization rate, and the RobT was the negative one (B = - 0.075, P = 0 0.009). In female carriers, we did not observe this difference (P = 0.227). CONCLUSIONS: In patients with chromosomal translocation, the fertilization rate may be influenced by carrier sex and translocation type, chromosomes 1-5 translocation may adversely affect the formation of available blastocysts. Break sites have no role in fertilization and blastocyst development.


Asunto(s)
Diagnóstico Preimplantación , Translocación Genética , Embarazo , Humanos , Masculino , Femenino , Estudios Retrospectivos , Fertilización In Vitro , Índice de Embarazo , Blastocisto , Desarrollo Embrionario/genética , Fertilización , Pruebas Genéticas
5.
Sci Rep ; 13(1): 15553, 2023 Sep 20.
Artículo en Inglés | MEDLINE | ID: mdl-37731039

RESUMEN

In this study, we comprehensively investigate the structure and operational principles of the Rotary Direct Drive Electro-Hydraulic Pressure Servo Valve (RDDPV). Our objective is to establish the dynamics equations governing the motor, slide valve, and bias mechanism of the valve. Additionally, we construct a mathematical model for the servo valve controller, while ensuring the linearization of the controller model. Furthermore, we conduct an in-depth analysis of the static characteristics of the valve, including linearity, dead zone, hysteresis loop, and zero drift. Regarding the dynamic characteristics, we establish a dynamic mathematical model for the RDDPV valve. Subsequently, we subject the servo valve to analysis with a focus on frequency response and dynamic response, using the control current as the input and the pressure as the output. To perform these analyses, we employ the software package SIMULINK of MATLAB, facilitating dynamic simulations. Remarkably, the simulation results exhibit the valve's conformity to design requirements, underscoring its suitability for subsequent research and development endeavors. Through our rigorous investigation, we offer essential technical support for the forthcoming stages of the valve's research and development, thereby laying a robust foundation for its further advancement.

6.
Chemistry ; 29(55): e202301619, 2023 Oct 02.
Artículo en Inglés | MEDLINE | ID: mdl-37403776

RESUMEN

Urea synthesis from abundant CO2 and N-feedstocks via renewable electricity has attracted increasing interests, offering a promising alternative to the industrial-applied Haber-Meiser process. However, the studies toward electrochemical urea production remain scarce and appeal for more research. Herein, in this perspective, an up-to-date overview on the urea electrosynthesis is highlighted and summarized. Firstly, the reaction pathways of urea formation through various feedstocks are comprehensively discussed. Then, we focus on the strategies of materials design to improve C-N coupling efficiency by identifying the descriptor and understanding the reaction mechanism. Finally, the current challenges and disadvantages in this field are reviewed and some future development directions of electrocatalytic urea synthesis are also prospected. This Minireview aims to promote future investigations of the electrochemical urea synthesis.

7.
Chemphyschem ; 24(16): e202300152, 2023 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-37309015

RESUMEN

Electrochemical reactions mostly take place at a constant potential, but traditional DFT calculations operate at a neutral charge state. In order to really model experimental conditions, we developed a fixed-potential simulation framework via the iterated optimization and self-consistence of the required Fermi level. The B-doped graphene-based FeN4 sites for oxygen reduction reaction were chosen as the model to evaluate the accuracy of the fixed-potential simulation. The results demonstrate that *OH hydrogenation gets facile while O2 adsorption or hydrogenation becomes thermodynamically unfavorable due to the lower d-band center of Fe atoms in the constant potential state than the neutral charge state. The onset potential of ORR over B-doped FeN4 by performing potential-dependent simulations agree well with experimental findings. This work indicates that the fixed-potential simulation can provide a reasonable and accurate description on electrochemical reactions.

8.
Matrix Biol ; 119: 1-18, 2023 05.
Artículo en Inglés | MEDLINE | ID: mdl-36958467

RESUMEN

Decreased vascular compliance of the large arteries as indicated by increased pulse wave velocity is shown to be associated with atherosclerosis and the related cardiovascular events. The positive correlation between arterial stiffening and disease progression derives a hypothesis that softening the arterial wall may protect against atherosclerosis, despite that the mechanisms controlling the cellular pathological changes in disease progression remain unknown. Here, we established a mechanical-property-based screening to look for compounds alleviating the arterial wall stiffness through their actions on the interaction between vascular smooth muscle cells (VSMCs) and the wall extracellular matrix (ECM). We found that echinatin, a chalcone preferentially accumulated in roots and rhizomes of licorice (Glycyrrhiza inflata), reduced the stiffness of ECM surrounding cultured VSMCs. We examined the potential beneficial effects of echinatin on mitigating arterial stiffening and atherosclerosis, and explored the mechanistic basis by which the compound exert the effects. Administration of echinatin in mice fed on an adenine diet and in hyperlipidemia mice subjected to 5/6 nephrectomy mitigated arterial stiffening and atherosclerosis. Mechanistic insights were gained from the RNA-sequencing results showing that echinatin upregulated the expression of glutamate cysteine ligases (GCLs), both the catalytic (GCLC) and modulatory (GCLM) subunits. Further study indicated that upregulation of GCLC/GCLM in VSMCs by echinatin maintains the homeostasis of glutathione (GSH) metabolism; adequate availability of GSH is critical for counteracting arterial stiffening. As a consequence of regulating the GSH synthesis, echinatin inhibits ferroptosis and matrix remodeling that being considered two contributors of arterial stiffening and atherosclerosis. These data demonstrate a pivotal role of GSH dysregulation in damaging the proper VSMC-ECM interaction and uncover a beneficial activity of echinatin in preventing vascular diseases.


Asunto(s)
Aterosclerosis , Chalconas , Ratones , Animales , Chalconas/metabolismo , Músculo Liso Vascular/metabolismo , Análisis de la Onda del Pulso , Arterias , Aterosclerosis/metabolismo , Homeostasis , Glutatión/metabolismo , Miocitos del Músculo Liso/metabolismo
9.
Circ Res ; 132(1): 87-105, 2023 01 06.
Artículo en Inglés | MEDLINE | ID: mdl-36475898

RESUMEN

BACKGROUND: The Hippo-YAP (yes-associated protein) signaling pathway is modulated in response to various environmental cues. Activation of YAP in vascular smooth muscle cells conveys the extracellular matrix stiffness-induced changes in vascular smooth muscle cells phenotype and behavior. Recent studies have established a mechanoreceptive role of receptor tyrosine kinase DDR1 (discoidin domain receptor 1) in vascular smooth muscle cells. METHODS: We conduced 5/6 nephrectomy in vascular smooth muscle cells-specific Ddr1-knockout mice, accompanied by pharmacological inhibition of the Hippo pathway kinase LATS1 (large tumor suppressor 1), to investigate DDR1 in YAP activation. We utilized polyacrylamide gels of varying stiffness or the DDR1 ligand, type I collagen, to stimulate the cells. We employed multiple molecular biological techniques to explore the role of DDR1 in controlling the Hippo pathway and to determine the mechanistic basis by which DDR1 exerts this effect. RESULTS: We identified the requirement for DDR1 in stiffness/collagen-induced YAP activation. We uncovered that DDR1 underwent stiffness/collagen binding-stimulated liquid-liquid phase separation and co-condensed with LATS1 to inactivate LATS1. Mutagenesis experiments revealed that the transmembrane domain is responsible for DDR1 droplet formation. Purified DDR1 N-terminal and transmembrane domain was sufficient to drive its reversible condensation. Depletion of the DDR1 C-terminus led to failure in co-condensation with LATS1. Interaction between the DDR1 C-terminus and LATS1 competitively inhibited binding of MOB1 (Mps one binder 1) to LATS1 and thus the subsequent phosphorylation of LATS1. Introduction of the single-point mutants, histidine-745-proline and histidine-902-proline, to DDR1 on the C-terminus abolished the co-condensation. In mouse models, YAP activity was positively correlated with collagen I expression and arterial stiffness. LATS1 inhibition reactivated the YAP signaling in Ddr1-deficient vessels and abrogated the arterial softening effect of Ddr1 deficiency. CONCLUSIONS: These findings identify DDR1 as a mediator of YAP activation by mechanical and chemical stimuli and demonstrate that DDR1 regulates LATS1 phosphorylation in an liquid-liquid phase separation-dependent manner.


Asunto(s)
Vía de Señalización Hippo , Histidina , Ratones , Animales , Proteínas Serina-Treonina Quinasas/genética , Proteínas Serina-Treonina Quinasas/metabolismo , Transducción de Señal , Colágeno , Colágeno Tipo I
10.
Front Psychol ; 14: 1328037, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-38274694

RESUMEN

Recycling apparel and fabrics is essential for preserving resources and protecting the environment, providing considerable global advantages for ecology and society. This study sought to explore the participation of Chinese college students in the recycling of clothing and fabrics by combining the Theory of Planned Behavior (TPB), the Value-Belief-Norm theory (VBN), self-identity, school education, and perceived policy effectiveness to create a comprehensive model. A total of 1,027 valid samples were obtained through stratified sampling and random sampling, primarily sourced from Eastern China, and analyzed through Structural Equation Modeling (SEM) utilizing AMOS. The results of the research suggested the following: (1) College students' biospheric values emerged as the most influential factor in predicting their inclination to participate in recycling behavior. (2) VBN (encompassing biospheric and altruistic values) and self-identity significantly contributed to shaping attitude and perceived behavioral control, which in turn impacted individuals' intention to participate in recycling. (3) School education exerted a stronger moderating influence than perceived policy effectiveness on the relationship between attitude, perceived behavioral control, and intention. The comprehensive model proposed in this study demonstrated superior predictive capability in explaining college students' willingness to participate in clothing and textiles recycling. It has been proven to be practical and effective. Lastly, schools should promote the practice of clothing and textiles recycling, cultivate good values, and utilize the power of social influence to encourage college students to participate in clothing and textiles recycling. The government should improve relevant laws and regulations, collaborate with academia, and adopt measures like incentives to create a pro-environment atmosphere.

11.
Materials (Basel) ; 15(23)2022 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-36500055

RESUMEN

The equiatomic CoCrFeNiMn high-entropy alloy (HEA) possesses excellent properties including exceptional strength-ductility synergy, high corrosion resistance, and good thermal stability. Selective laser melting (SLM) additive manufacturing facilitates the convenient fabrication of the CoCrFeNiMn HEA parts with complex geometries. Here, the SLM process optimization was conducted to achieve a high relative density of as-built CoCrFeNiMn HEA bulks. The mechanisms of process-induced defects and process control were elucidated. The microscale mechanical behaviors were analyzed through in situ scanning electron microscopy observation during the compression tests on micro-pillars of the as-built HEA. The stress-strain characteristics by repeated slip and mechanism of "dislocation avalanche" during the compression of micro-pillars were discussed. The high-cycle fatigue tests of the as-built HEA were performed. It was found that a large number of nano-twins were induced by the fatigue, causing a non-negligible cycle softening phenomenon. The effects of promoted ductility due to the fatigue-induced nano-twins were illustrated. This work has some significance for the engineering application of the SLM additively manufactured CoCrFeNiMn HEA parts.

12.
Front Endocrinol (Lausanne) ; 13: 895939, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36157457

RESUMEN

Objective: To explore the risk factors of ectopic pregnancy after in vitro fertilization. Methods: This retrospective cohort study was conducted at the Reproductive Medical Center of the Third Affiliated Hospital of Zhengzhou University from January 2016 to April 2020. Univariate and multivariate analysis were used to analyze the related factors affecting the occurrence of ectopic pregnancy (EP) and to construct a nomographic prediction model for the incidence of ectopic pregnancy. Results: A total of 12,766 cycles of 10109 patients were included, comprising 214 cases of EP and 12,552 cases of intrauterine pregnancy (IUP). Multivariate logistic regression analysis showed that the tubal factor was associated with a 2-fold increased risk for EP (aOR = 2.72, 95% CI: 1.69-4.39, P < 0.0001). A stratified analysis showed that women with an endometrial thickness (EMT) between 7.6 to 12.1mm (aOR = 0.57, 95%CI: 0.36-0.90, P = 0.0153) and >12.1mm (aOR = 0.42, 95%CI: 0.24-0.74, P = 0.0026) had a significant reduction of the risk of EP compared to women with an EMT of <7.6mm. Compared to cleavage stage transfer, blastocyst transfer can reduce the risk of ectopic pregnancy (aOR = 0.36, 95%CI: 0.26-0.50, P < 0.0001). The saturation model (full mode) establishes a nomographic prediction model with an AUC = 0.68 and a sensitivity and specificity of 0.67and 0.64, respectively. The nomination model was internally verified by self-sampling method (bootstrap sampling resampling times = 500). The resulting AUC = 0.68 (sensitivity: 0.65; specificity: 0.65) showed that the model was relatively stable. Conclusions: Our findings indicate that EMT is inversely proportional to the risk of EP. Embryo stage, number of embryos transferred were also significantly associated with EP rate. A simple nomogram for the predicting the risk of EP was established in order to reduce the occurrence of EP.


Asunto(s)
Fertilización In Vitro , Embarazo Ectópico , Transferencia de Embrión/métodos , Femenino , Fertilización In Vitro/efectos adversos , Humanos , Embarazo , Índice de Embarazo , Embarazo Ectópico/diagnóstico , Embarazo Ectópico/epidemiología , Embarazo Ectópico/etiología , Estudios Retrospectivos
13.
Water Res ; 221: 118801, 2022 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-35810635

RESUMEN

Optimizing methane production from food waste (FW) efficiently is always a hot topic in the field of anaerobic digestion (AD). In this study we aimed to improve the conversion of organics to methane by using CaO2 and magnetite to enhance the semi-continuous AD of food waste. Under the organic load of 2.5 g VS/L·d-1, the specific methane yield was increased from 333.9 mL CH4/g·VS to 423.4 mL CH4/g·VS by adding 0.01 g/L CaO2 with 0.4 g/L magnetite, improving the production of methane from FW. We assessed reactor performance, ORP changes, mass balance, enzyme activities and characterized the metagenomic profile of microorganisms involved in digestion. These microorganisms showed rapid conversion of volatile fatty acids and increased expression of genes related to hydrolysis and acid production. Thus, the addition of CaO2 and magnetite optimized the relationship between fermentation bacteria and methanogenic archaea to enhance the overall production of methane. Microorganisms evolved unique adaptive mechanisms in the co-operative environment of CaO2 and magnetite, as their energy metabolism patterns combined those controlled by individual CaO2 and magnetite addition. This method of combining a micro-aeration environment with conductive materials provides a new perspective for optimizing the AD of FW.


Asunto(s)
Alimentos , Eliminación de Residuos , Anaerobiosis , Reactores Biológicos , Óxido Ferrosoférrico , Metano/metabolismo , Peróxidos , Eliminación de Residuos/métodos , Aguas del Alcantarillado/microbiología
14.
Adv Sci (Weinh) ; 9(23): e2200534, 2022 08.
Artículo en Inglés | MEDLINE | ID: mdl-35723422

RESUMEN

Ion transport under nanoconfined spaces is a ubiquitous phenomenon in nature and plays an important role in the energy conversion and signal transduction processes of both biological and artificial systems. Unlike the free diffusion in continuum media, anomalous behaviors of ions are often observed in nanostructured systems, which is governed by the complex interplay between various interfacial interactions. Conventionally, nanoionics mainly refers to the study of ion transport in solid-state nanosystems. In this review, to extent this concept is proposed and a new framework to understand the phenomena, mechanism, methodology, and application associated with ion transport at the nanoscale is put forward. Specifically, here nanoionics is summarized into three categories, i.e., biological, artificial, and hybrid, and discussed the characteristics of each system. Compared with nanoelectronics, nanoionics is an emerging research field with many theoretical and practical challenges. With this forward-looking perspective, it is hoped that nanoionics can attract increasing attention and find wide range of applications as nanoelectronics.


Asunto(s)
Nanoestructuras , Difusión , Transporte Iónico , Iones
16.
Biochem Biophys Res Commun ; 607: 166-173, 2022 06 04.
Artículo en Inglés | MEDLINE | ID: mdl-35381387

RESUMEN

Von Willebrand Factor (VWF) can promote platelet adhesion to the post-atherosclerotic regions to initiate thrombosis. The synthesis and secretion of VWF are important functions of endothelial cells (ECs). However, the mechanism through which blood flow regulates endothelial secretion of VWF remains unclear. We utilized a parallel-plate flow apparatus to apply fluid shear stress to human umbilical vein endothelial cells (HUVECs). Compared with pulsatile shear stress that mimics laminar flow in the straight parts of arteries or upstream of atherosclerotic stenosis sites, short-term exposure to oscillatory shear stress (OS) that mimics disturbed flow increased VWF secretion independent of affecting synaptosomal-associated protein 23 (SNAP23) expression and promoted the translocation of SNAP23 to the cell membrane. Vimentin associated with SNAP23, and this association was enhanced by OS or histamine. Acrylamide, a reagent that disrupts vimentin intermediate filaments, prevented histamine/OS-induced SNAP23 translocation, as well as VWF secretion. Immunofluorescence analysis revealed that the polarity of the vimentin intermediate filament network decreased after stimulation with histamine or OS. In addition, inhibition of protein kinase A (PKA) or G protein coupled receptor 68 (GPR68) eliminated the histamine/OS-induced phosphorylation of vimentin at Ser38 and secretion of VWF. Furthermore, syntaxin 7 might assist with the translocation of SNAP23 to the cell membrane, thus playing a role in promoting VWF secretion. The GPR68/PKA/vimentin signaling pathway may represent a novel mechanism for the regulation of SNAP23-mediated VWF secretion by ECs under OS and provide strategies for the prevention of atherosclerosis-related thrombosis.


Asunto(s)
Trombosis , Factor de von Willebrand , Proteínas Quinasas Dependientes de AMP Cíclico/metabolismo , Histamina/metabolismo , Células Endoteliales de la Vena Umbilical Humana/metabolismo , Humanos , Filamentos Intermedios/metabolismo , Mecanotransducción Celular , Proteínas Qb-SNARE/metabolismo , Proteínas Qc-SNARE/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Estrés Mecánico , Trombosis/metabolismo , Vimentina/metabolismo , Factor de von Willebrand/metabolismo
17.
Polymers (Basel) ; 15(1)2022 Dec 29.
Artículo en Inglés | MEDLINE | ID: mdl-36616524

RESUMEN

For manipulating heat flow according to human desire, thermal metamaterial structures (meta-structures) have attracted growing interest. Based on the transformation thermotics and the effective medium approximation theory, we designed and fabricated a convertible thermal meta-structural device to demonstrate that multiple different heat-flow manipulations could be conducted using a single thermal meta-structural device. The convertible meta-structures were designed by discretizing a two-dimensional plane and separating multiple square unit modules with stripe-shaped dissimilar materials of the Polydimethylsiloxane (PDMS) and solid resin with surface metallized copper (Cu). The convertible thermal meta-structure device with a relatively high geometric accuracy was fabricated via a proposed hybrid manufacturing path of "Stereolithography Apparatus (SLA) 3D printing-electroless plating-electroplating-thermally insulated packaging". The thermal manipulation features were numerically simulated and preliminarily verified by experimental testing. Using multiple dispersed square unit modules to replace an annular region of the thermal meta-structure exhibited different thermal flow functions, including thermal cloak, thermal concentration, thermal rotation, and thermal dispersion, through the unique geometric design of the heat-flow transfer direction within each module. By rotating each square unit module at a specific angle and arranging the modules, similar to a "jigsaw puzzle", the convertibility among different thermal manipulation functions was achieved. This path is anticipated to provide a new strategy for multifunctional meta-structures in thermo-physics and its potential engineering applications.

18.
Sheng Li Xue Bao ; 74(6): 894-902, 2022 Dec 25.
Artículo en Chino | MEDLINE | ID: mdl-36594378

RESUMEN

Cardiovascular homeostasis is regulated by both physical and chemical factors. Vascular stiffness, a physical property of vessel, is crucial in maintaining the physiological function of vasculature. Vascular stiffness has been indicated to be correlated with hypertension, heart failure and other cardiovascular diseases. It has been the most widely accepted clinical index for assessment of vascular function and dysfunction. This paper reviews the commonly used experimental and clinical techniques for evaluating vascular stiffness including direct detection of the Young's modulus and indirect detection method that is based on ultrasound technique and others. Principles of these methodologies, as well as their advantages and disadvantages, are also presented here. Researchers and clinical staff are encouraged to choose the most suitable methods for detecting vascular stiffness according to their purposes and objects, so as to effectively evaluate vascular function.


Asunto(s)
Enfermedades Cardiovasculares , Insuficiencia Cardíaca , Hipertensión , Rigidez Vascular , Humanos , Módulo de Elasticidad , Hipertensión/diagnóstico , Enfermedades Cardiovasculares/diagnóstico
19.
Materials (Basel) ; 14(23)2021 Nov 27.
Artículo en Inglés | MEDLINE | ID: mdl-34885403

RESUMEN

A microchannel radiator is advantageous due to its high efficiency and large boiling heat transfer coefficient of two-phase flow. Based on the research of uniform lattice structures, this study proposed a microchannel heat exchanger with a nonuniform lattice structure. The calculation, optimal formation, and boiling heat transfer performance of the nonuniform lattice structure based on selective laser melting (SLM) were investigated, and heat exchange samples were successfully prepared using SLM. The porosity and pore morphology of the samples were analysed, and the contrast experiments of boiling heat transfer were conducted with deionised water. The results revealed that the heat flow density of the lattice structure was a minimum of 244% higher than that of the traditional liquid-cooled plate. The critical heat flux density of the lattice structure is 110 W∙cm-2, and the critical heat flux density of the traditional flat plate is 45 W∙cm-2. In addition, the effects of cell structures indicated that for frame cells, the heat transfer effect of nonuniform frames was inferior to that of uniform frames; for face-centred cubic (FCC) cells, the nonuniform and uniform frames exhibited the same trend. However, the heat flow density of FCC cells was 25% higher than that of frame structures.

20.
Sci Rep ; 11(1): 6947, 2021 Mar 25.
Artículo en Inglés | MEDLINE | ID: mdl-33767273

RESUMEN

Aiming at laser powder bed fusion of GH3536 nickel base alloy, the effects of different scanning strategies on microstructure, porosity and mechanical properties were explored. In the aspect of microstructure and micro hardness of the sample, three scanning strategies had little difference; in the aspect of macro mechanical properties of the sample, the slope subarea scanning was better than the helix and island scanning. On this basis, the slope subarea scanning was selected as the optimal scanning strategy to form the G-surface structure, and the compression performance of G-surface was studied. The results showed that: (1) the compression performance of G-surface structure was smaller than that of solid structure, The compression strength of G-surface can only reach about 20% of solid structure: the average strength value of G-surface is 220 MPa, solid structure is 1.1 GMpa; while G-surface structure had a smooth compression curve, which indicated the good energy absorption characteristics; (2) with the increase of wall thickness, the mechanical performance of G-surface structure was also enhanced, while the energy absorption capacity was constantly reduced; (3) with the same wall thickness, the compression performance of sample in building direction (BD) is higher than that in horizontal direction (HD).

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