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1.
Biomaterials ; 305: 122462, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38171118

RESUMEN

Liver sinusoidal endothelial cells (LSECs) are highly specific endothelial cells which play an essential role in the maintenance of liver homeostasis. During the progression of liver fibrosis, matrix stiffening promotes LSEC defenestration, however, the underlying mechanotransduction mechanism remains poorly understood. Here, we applied stiffness-tunable hydrogels to assess the matrix stiffening-induced phenotypic changes in primary mouse LSECs. Results indicated that increased stiffness promoted LSEC defenestration through cytoskeletal reorganization. LSECs sensed the increased matrix stiffness via focal adhesion kinase (FAK), leading to the activation of p38-mitogen activated protein kinase activated protein kinase 2 (MK2) pathway, thereby inducing actin remodeling via LIM Kinase 1 (LIMK1) and Cofilin. Interestingly, inhibition of FAK or p38-MK2 pathway was able to effectively restore the fenestrae to a certain degree in LSECs isolated from early to late stages of liver fibrosis mice. Thus, this study highlights the impact of mechanotransduction in LSEC defenestration, and provides novel insights for potential therapeutic interventions for liver fibrosis.


Asunto(s)
Células Endoteliales , Mecanotransducción Celular , Ratones , Animales , Células Endoteliales/metabolismo , Proteína-Tirosina Quinasas de Adhesión Focal/metabolismo , Hígado/patología , Cirrosis Hepática/patología
2.
ACS Appl Mater Interfaces ; 16(1): 1129-1136, 2024 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-38118124

RESUMEN

Materials with strong spin-orbit coupling (SOC) have been continuously attracting intensive attention due to their promising application in energy-efficient, high-density, and nonvolatile spintronic devices. Particularly, transition-metal perovskite oxides with strong SOC have been demonstrated to exhibit efficient charge-spin interconversion. In this study, we systematically investigated the impact of epitaxial strain on the spin-orbit torque (SOT) efficiency in the SrIrO3(SIO)/Ni81Fe19(Py) bilayer. The results reveal that the SOT efficiency is strongly related to the octahedral rotation around the in-plane axes of the single-crystal SIO. By modulating the epitaxial strain using different substrates, the SOT efficiency can be remarkably improved from 0.15 to 1.45. This 10-fold enhancement of SOT efficiency suggests that modulating the epitaxial strain is an efficient approach to control the SOT efficiency in complex oxide-based heterostructures. Our work may have the potential to advance the application of complex oxides in energy-efficient spintronic devices.

3.
JHEP Rep ; 5(12): 100905, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37920845

RESUMEN

Background & Aims: Liver paracrine signaling from liver sinusoid endothelial cells to hepatocytes in response to mechanical stimuli is crucial in highly coordinated liver regeneration. Interstitial flow through the fenestrated endothelium inside the space of Disse potentiates the role of direct exposure of hepatocytes to fluid flow in the immediate regenerative responses after partial hepatectomy, but the underlying mechanisms remain unclear. Methods: Mouse liver perfusion was used to identify the effects of interstitial flow on hepatocyte proliferation ex vivo. Isolated hepatocytes were further exposed to varied shear stresses directly in vitro. Knockdown and/or inhibition of mechanosensitive proteins were used to unravel the signaling pathways responsible for cell proliferation. Results: An increased interstitial flow was visualized and hepatocytes' regenerative response was demonstrated experimentally by ex vivo perfusion of mouse livers. In vitro measurements also showed that fluid flow initiated hepatocyte proliferation in a duration- and amplitude-dependent manner. Mechanistically, flow enhanced ß1 integrin expression and nuclear translocation of YAP (yes-associated protein), via the Hippo pathway, to stimulate hepatocytes to re-enter the cell cycle. Conclusions: Hepatocyte proliferation was initiated after direct exposure to interstitial flow ex vivo or shear stress in vitro, which provides new insights into the contributions of mechanical forces to liver regeneration. Impact and implications: By using both ex vivo liver perfusion and in vitro flow exposure tests, we identified the roles of interstitial flow in the space of Disse in stimulating hepatocytes to re-enter the cell cycle. We found an increase in shear flow-induced hepatocyte proliferation via ß1 integrin-YAP mechanotransductive pathways. This serves as a useful model to potentiate hepatocyte expansion in vitro using mechanical forces.

4.
Am J Obstet Gynecol MFM ; 5(8): 100999, 2023 08.
Artículo en Inglés | MEDLINE | ID: mdl-37548246

RESUMEN

BACKGROUND: Birthweight is the most common and accessible parameter in assessing neonatal perinatal outcomes and in evaluating the intrauterine environment globally. Infants born too large or too small not only may alter the maternal mode of delivery but also may face other long-term disorders, such as metabolic diseases and neurodevelopmental delay. Studies have revealed different growth profiles of large-for-gestational-age and small-for-gestational-age fetuses in singleton pregnancies. However, currently, no research is focused on the growth trajectories of these infants during twin pregnancies, even though they are at a much higher risk of being small for gestational age. OBJECTIVE: This study aimed to explore fetal growth trajectories of large-for-gestational-age and small-for-gestational-age infants in twin pregnancies to provide strategies for fetal growth management. STUDY DESIGN: This was a case-control study of all noncomplicated twin pregnancies delivered after 36 weeks of gestation at the Peking University First Hospital between 2012 and 2021. Ultrasound data were recorded every 2 to 4 weeks until delivery. All the infants were divided into large-for-gestational-age, small-for-gestational-age, and appropriate-for-gestational-age groups. Longitudinal fetal growth (estimated fetal weight, abdominal circumference, etc.) was compared among the 3 groups using a linear mixed model, and other maternal and neonatal perinatal outcomes were compared. Receiver operating characteristic curves were used to explore optimal biometric parameters and gestational weeks for predicting small-for-gestational-age infants. RESULTS: Here, 797 pregnant patients with 1494 infants were recruited, with 59 small-for-gestational-age infants, 1335 appropriate-for-gestational-age infants, and 200 large-for-gestational-age infants. The mean birthweights were 1985.34±28.34 g in small-for-gestational-age infants, 2662.08±6.60 g in appropriate-for-gestational-age infants, and 3231.24±11.04 g in large-for-gestational-age infants. The estimated fetal weight of the 3 groups differed from each other from week 26, with the small-for-gestational-age fetuses weighing 51.946 g less and the large-for-gestational-age fetuses weighing 35.233 g more than the appropriate-for-gestational-age fetuses. This difference increased with gestation; at 39 weeks, the small-for-gestational-age fetuses weighed 707.438 g less and the large-for-gestational-age fetuses weighed 614.182 g more than the appropriate-for-gestational-age fetuses (all P<.05). The small-for-gestational-age group had a significantly higher rate of hospitalization (89.9 %) and jaundice (40.7 %) than the appropriate-for-gestational-age group, whereas the hospitalization rate in the large-for-gestational-age group was significantly lower than the appropriate-for-gestational-age group (7.5% and 2.5%; all P<.05). The fetal weight of the small-for-gestational-age infants with adverse outcomes remained near the 10th percentile of the reference and fell below the 3rd percentile at 34 weeks of gestation. The estimated fetal weight after 30 weeks of gestation had a satisfactory diagnostic value in predicting small-for-gestational-age infants. At 30, 32, 34, and 36 weeks of gestation, the areas under the curve were 0.829, 0.840, 0.929, and 0.889 respectively. CONCLUSION: The growth patterns of small-for-gestational-age, appropriate-for-gestational-age, and large-for-gestational-age twin fetuses diverged from 26 weeks of gestation and continued to increase until delivery; therefore, closer monitoring is suggested from 26 weeks of gestation for those carrying small fetuses.


Asunto(s)
Retardo del Crecimiento Fetal , Peso Fetal , Bebé Grande para la Edad Gestacional , Embarazo Gemelar , Femenino , Humanos , Lactante , Recién Nacido , Embarazo , Peso al Nacer , Estudios de Casos y Controles , Desarrollo Fetal , Retardo del Crecimiento Fetal/diagnóstico , Retardo del Crecimiento Fetal/epidemiología , Edad Gestacional , Ultrasonografía Prenatal
5.
Nat Commun ; 14(1): 4012, 2023 Jul 07.
Artículo en Inglés | MEDLINE | ID: mdl-37419923

RESUMEN

Chemical reduction in oxides plays a crucial role in engineering the material properties through structural transformation and electron filling. Controlling the reduction at nanoscale forms a promising pathway to harvest functionalities, which however is of great challenge for conventional methods (e.g., thermal treatment and chemical reaction). Here, we demonstrate a convenient pathway to achieve nanoscale chemical reduction for vanadium dioxide through the electron-beam illumination. The electron beam induces both surface oxygen desorption through radiolytic process and positively charged background through secondary electrons, which contribute cooperatively to facilitate the vacancy migration from the surface toward the sample bulk. Consequently, the VO2 transforms into a reduced V2O3 phase, which is associated with a distinct insulator to metal transition at room temperature. Furthermore, this process shows an interesting facet-dependence with the pronounced transformation observed for the c-facet VO2 as compared with the a-facet, which is attributed to the intrinsically different oxygen vacancy formation energy between these facets. Remarkably, we readily achieve a lateral resolution of tens nanometer for the controlled structural transformation with a commercial scanning electron microscope. This work provides a feasible strategy to manipulate the nanoscale chemical reduction in complex oxides for exploiting functionalities.


Asunto(s)
Electrones , Iluminación , Ingeniería , Óxidos , Oxígeno
6.
Front Bioeng Biotechnol ; 11: 1165651, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37214300

RESUMEN

The liver is a complicated organ within the body that performs wide-ranging and vital functions and also has a unique regenerative capacity after hepatic tissue injury and cell loss. Liver regeneration from acute injury is always beneficial and has been extensively studied. Experimental models including partial hepatectomy (PHx) reveal that extracellular and intracellular signaling pathways can help the liver recover to its equivalent size and weight prior to an injury. In this process, mechanical cues possess immediate and drastic changes in liver regeneration after PHx and also serve as main triggering factors and significant driving forces. This review summarized the biomechanics progress in liver regeneration after PHx, mainly focusing on PHx-based hemodynamics changes in liver regeneration and the decoupling of mechanical forces in hepatic sinusoids including shear stress, mechanical stretch, blood pressure, and tissue stiffness. Also discussed were the potential mechanosensors, mechanotransductive pathways, and mechanocrine responses under varied mechanical loading in vitro. Further elucidating these mechanical concepts in liver regeneration helps establish a comprehensive understanding of the biochemical factors and mechanical cues in this process. Proper adjustment of mechanical loading within the liver might preserve and restore liver functions in clinical settings, serving as an effective therapy for liver injury and diseases.

7.
ACS Appl Mater Interfaces ; 15(14): 17577-17591, 2023 Apr 12.
Artículo en Inglés | MEDLINE | ID: mdl-36976830

RESUMEN

Migrating neutrophils are found to leave behind subcellular trails in vivo, but the underlying mechanisms remain unclear. Here, an in vitro cell migration test plus an in vivo observation was applied to monitor neutrophil migration on intercellular cell adhesion molecule-1 (ICAM-1) presenting surfaces. Results indicated that migrating neutrophils left behind long-lasting, chemokine-containing trails. Trail formation tended to alleviate excessive cell adhesion enhanced by the trans-binding antibody and maintain efficient cell migration, which was associated with differential instantaneous edge velocity between the cell front and rear. CD11a and CD11b worked differently in inducing trail formation with polarized distributions on the cell body and uropod. Trail release at the cell rear was attributed to membrane ripping, in which ß2-integrin was disrupted from the cell membrane through myosin-mediated rear contraction and integrin-cytoskeleton dissociation, potentiating a specialized strategy of integrin loss and cell deadhesion to maintain efficient migration. Moreover, neutrophil trails left on the substrate served as immune forerunners to recruit dendritic cells. These results provided an insight in elucidating the mechanisms of neutrophil trail formation and deciphering the roles of trail formation in efficient neutrophil migration.


Asunto(s)
Movimiento Celular , Neutrófilos , Adhesión Celular , Neutrófilos/citología , Neutrófilos/metabolismo , Masculino , Animales , Ratones , Ratones Endogámicos C57BL , Células Cultivadas , Espectroscopía Infrarroja por Transformada de Fourier , Citocinas/metabolismo , Células Dendríticas/citología , Células Dendríticas/metabolismo
8.
Int J Mol Sci ; 24(3)2023 Jan 22.
Artículo en Inglés | MEDLINE | ID: mdl-36768527

RESUMEN

Microgravity exposure during spaceflight causes the disordered regulation of liver function, presenting a specialized mechano-biological coupling process. While YAP/TAZ serves as a typical mechanosensitive pathway involved in hepatocyte metabolism, it remains unclear whether and how it is correlated with microgravity-induced liver dysfunction. Here, we discussed liver function alterations induced by spaceflight or simulated effects of microgravity on Earth. The roles of YAP/TAZ serving as a potential bridge in connecting liver metabolism with microgravity were specifically summarized. Existing evidence indicated that YAP/TAZ target gene expressions were affected by mechanotransductive pathways and phase separation, reasonably speculating that microgravity might regulate YAP/TAZ activation by disrupting these pathways via cytoskeletal remodeling or nuclear deformation, or disturbing condensates formation via diffusion limit, and then breaking liver homeostasis.


Asunto(s)
Hepatopatías , Vuelo Espacial , Humanos , Proteínas Adaptadoras Transductoras de Señales/genética , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Hepatopatías/etiología , Mecanotransducción Celular/fisiología , Transactivadores/metabolismo , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Proteínas Señalizadoras YAP/metabolismo , Proteínas Coactivadoras Transcripcionales con Motivo de Unión a PDZ/metabolismo
9.
World J Clin Cases ; 10(24): 8782-8787, 2022 Aug 26.
Artículo en Inglés | MEDLINE | ID: mdl-36157822

RESUMEN

BACKGROUND: Cervical squamous cell carcinoma (SCC) is the most common type of cervical carcinoma and is generally derived from a precancerous stage called cervical high-grade squamous intraepithelial lesion (HSIL). Usually, the cancer metastasizes through lymphatic or hematogenous dissemination, but rarely spreads upward into the uterus. Here, we report a case of cervical HSIL extending into the endometrium and finally progressing to SCC in the uterine cavity. CASE SUMMARY: A 57-year-old postmenopausal woman visited our department and requested a routine cervical check-up. Four years ago, she had undergone a cervical loop electrosurgical excision procedure because of HSIL found during the gynecological examination, and she had not been checked again since. This time, a relapse of the cervical HSIL was diagnosed along with uterine pyometra and endometrial polyps. After 2 wk of antibiotic treatment, a laparoscopic hysterectomy was performed, and the final pathological examination revealed that the cervical HSIL had spread directly upward into the uterine cavity, gradually developing into cervical SCC in the endometrium. CONCLUSION: Cervical HSIL/SCC can directly spread upward into the uterus with the most common symptoms of pyometra and cervical stenosis. More attention should be given to the early detection and prevention of this disease.

10.
Adv Drug Deliv Rev ; 188: 114448, 2022 09.
Artículo en Inglés | MEDLINE | ID: mdl-35820602

RESUMEN

A growing body of multiscale biomechanical studies has been proposed to highlight the mechanical cues in the development of hepatic fibrosis and cancer. At the cellular level, changes in mechanical microenvironment induce phenotypic and functional alterations of hepatic cells, initiating a positive feedback loop that promotes liver fibrogenesis and hepatocarcinogenesis. Tumor mechanical microenvironment of hepatocellular carcinoma facilitates tumor cell growth and metastasis, and hinders the drug delivery and immunotherapy. At the molecular level, mechanical forces are sensed and transmitted into hepatic cells via allosteric activation of mechanoreceptors on the cell membrane, leading to the activation of various mechanotransduction pathways including integrin and YAP signaling and then regulating cell function. Thus, the application of mechanomedicine concept in the treatment of liver diseases is promising for rational design and cell-specific delivery of therapeutic drugs. This review mainly discusses the correlation between biomechanical cues and liver diseases from the viewpoint of mechanobiology.


Asunto(s)
Hepatopatías , Neoplasias Hepáticas , Neoplasias , Fenómenos Biomecánicos , Biofisica , Humanos , Hígado/metabolismo , Cirrosis Hepática/patología , Hepatopatías/patología , Neoplasias Hepáticas/patología , Mecanotransducción Celular , Neoplasias/metabolismo , Microambiente Tumoral
11.
Nat Commun ; 13(1): 3539, 2022 Jun 20.
Artículo en Inglés | MEDLINE | ID: mdl-35725723

RESUMEN

All-electric switching of perpendicular magnetization is a prerequisite for the integration of fast, high-density, and low-power magnetic memories and magnetic logic devices into electric circuits. To date, the field-free spin-orbit torque (SOT) switching of perpendicular magnetization has been observed in SOT bilayer and trilayer systems through various asymmetric designs, which mainly aim to break the mirror symmetry. Here, we report that the perpendicular magnetization of CoxPt100-x single layers within a special composition range (20 < x < 56) can be deterministically switched by electrical current in the absence of external magnetic field. Specifically, the Co30Pt70 shows the largest out-of-plane effective field efficiency and best switching performance. We demonstrate that this unique property arises from the cooperation of two structural mechanisms: the low crystal symmetry property at the Co platelet/Pt interfaces and the composition gradient along the thickness direction. Compared with that in bilayers or trilayers, the field-free switching in CoxPt100-x single layer greatly simplifies the SOT structure and avoids additional asymmetric designs.

12.
Adv Mater ; 34(33): e2109449, 2022 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-35751473

RESUMEN

Van der Waals materials are attracting great attention in the field of spintronics due to their novel physical properties. For example, they are utilized as spin-current generating materials in spin-orbit torque (SOT) devices, which offers an electrical way to control the magnetic state and is promising for future low-power electronics. However, SOTs have mostly been demonstrated in vdW materials with strong spin-orbit coupling (SOC). Here, the observation of a current-induced SOT in the h-BN/SrRuO3 bilayer structure is reported, where the vdW material (h-BN) is an insulator with negligible SOC. Importantly, this SOT is strong enough to induce the switching of the perpendicular magnetization in SrRuO3 . First-principles calculations suggest a giant Rashba effect at the interface between vdW material and SrRuO3 (110)pc thin film, which leads to the observed SOT based on a simplified tight-binding model. Furthermore, it is demonstrated that the current-induced magnetization switching can be modulated by the electric field. This study paves the way for exploring the current-induced SOT and magnetization switching by integrating vdW materials with ferromagnets.

13.
World J Clin Cases ; 10(10): 3206-3212, 2022 Apr 06.
Artículo en Inglés | MEDLINE | ID: mdl-35611135

RESUMEN

BACKGROUND: Uterine myoma is the most common benign tumor among women and is often accompanied by anemia. Here, we report the case of a patient with a very large leiomyoma but with a hemoglobin level as high as 197 g/L. After undergoing hysterectomy, all her hematological parameters returned to normal. Immunohistochemical staining of her myoma for erythropoietin showed strong positivity, which suggested that erythropoietin may be the cause of her erythrocytosis. A multidisciplinary team played a significant role in treating the disease. CASE SUMMARY: A 47-year-old woman visited our department complaining that her abdomen had been continuously growing for the past 2 years. After careful examinations, she was suspected of having a very large leiomyoma. She was also diagnosed with erythrocytosis because her RBC count was 6.49 × 1012/L, hemoglobin was 197 g/L. Following a multidisciplinary team consultation, bilateral ureteral stents were placed, and 800 mL blood was removed by phlebotomy. The patient then underwent hysterectomy and bilateral salpingectomy. She recovered well from the operation, and her hemoglobin level decreased sharply following the surgery. Low-molecular-weight heparin was administered daily to prevent postoperative thrombosis. She was discharged from the hospital on the fourth postoperative day. Two months later, all her hematological parameters returned to normal. Pathological analysis of the myoma revealed that it was a benign leiomyoma, with partial hyalinization, and strong positivity for erythropoietin in immunohistochemical staining suggested that erythropoietin may be responsible for the erythrocytosis. CONCLUSION: Erythropoietin ectopically produced from the myoma was responsible for the erythrocytosis in this patient. A multidisciplinary team is strongly recommended.

14.
Adv Mater ; 33(36): e2101316, 2021 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-34302392

RESUMEN

The magnetic Weyl fermion originates from the time reversal symmetry (TRS)-breaking in magnetic crystalline structures, where the topology and magnetism entangle with each other. Therefore, the magnetic Weyl fermion is expected to be effectively tuned by the magnetic field and electrical field, which holds promise for future topologically protected electronics. However, the electrical field control of the magnetic Weyl fermion has rarely been reported, which is prevented by the limited number of identified magnetic Weyl solids. Here, the electric field control of the magnetic Weyl fermion is demonstrated in an epitaxial SrRuO3 (111) thin film. The magnetic Weyl fermion in the SrRuO3 films is indicated by the chiral anomaly induced magnetotransport, and is verified by the observed Weyl nodes in the electronic structures characterized by the angle-resolved photoemission spectroscopy (ARPES) and first-principles calculations. Through the ionic-liquid gating experiment, the effective manipulation of the Weyl fermion by electric field is demonstrated, in terms of the sign-change of the ordinary Hall effect, the nonmonotonic tuning of the anomalous Hall effect, and the observation of the linear magnetoresistance under proper gating voltages. The work may stimulate the searching and tuning of Weyl fermions in other magnetic materials, which are promising in energy-efficient electronics.

15.
Adv Mater ; 33(36): e2103672, 2021 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-34302404

RESUMEN

Neuromorphic computing has become an increasingly popular approach for artificial intelligence because it can perform cognitive tasks more efficiently than conventional computers. However, it remains challenging to develop dedicated hardware for artificial neural networks. Here, a simple bilayer spintronic device for hardware implementation of neuromorphic computing is demonstrated. In L11 -CuPt/CoPt bilayer, current-inducted field-free magnetization switching by symmetry-dependent spin-orbit torques shows a unique domain nucleation-dominated magnetization reversal, which is not accessible in conventional bilayers. Gradual domain nucleation creates multiple intermediate magnetization states which form the basis of a sigmoidal neuron. Using the L11 -CuPt/CoPt bilayer as a sigmoidal neuron, the training of a deep learning network to recognize written digits, with a high recognition rate (87.5%) comparable to simulation (87.8%) is further demonstrated. This work offers a new scheme of implementing artificial neural networks by magnetic domain nucleation.


Asunto(s)
Cobalto/química , Cobre/química , Aprendizaje Profundo , Platino (Metal)/química , Algoritmos , Simulación por Computador , Sistemas de Computación , Redes Neurales de la Computación , Neuronas , Torque
16.
Adv Mater ; 33(30): e2007114, 2021 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-34145647

RESUMEN

Spin-orbit torque (SOT), which arises from the spin-orbit coupling of conduction electrons, is believed to be the key route for developing low-power, high-speed, and nonvolatile memory devices. Despite the theoretical prediction of pronounced Berry phase curvatures in certain transition-metal perovskite oxides, which lead to considerable intrinsic spin Hall conductivity, SOT from this class of materials has rarely been reported until recently. Here, the SOT generated by epitaxial SrRuO3 of three different crystal structures is systematically studied. The results of both spin-torque ferromagnetic resonance and in-plane harmonic Hall voltage measurements concurrently reveal that the intrinsic SOT efficiency of SrRuO3 decreases when the epitaxial strain changes from tensile to compressive. The X-ray diffraction data demonstrate a strong correlation between the magnitude of SOT and octahedral rotation around the in-plane axes of SrRuO3 , consistent with the theoretical prediction. This work offers new possibilities of tuning SOT with crystal structures and novel opportunities of integrating the unique properties of perovskite oxides with spintronic functionalities.

17.
Biomater Sci ; 9(10): 3776-3790, 2021 May 18.
Artículo en Inglés | MEDLINE | ID: mdl-33876166

RESUMEN

Mechanical or physical cues are associated with the growth and differentiation of embryonic stem cells (ESCs). While the substrate stiffness or topography independently affects the differentiation of ESCs, their cooperative regulation on lineage-specific differentiation remains largely unknown. Here, four topographical configurations on stiff or soft polyacrylamide hydrogel were combined to direct hepatic differentiation of human H1 cells via a four-stage protocol, and the coupled impacts of stiffness and topography were quantified at distinct stages. Data indicated that the substrate stiffness is dominant in stemness maintenance on stiff gel and hepatic differentiation on soft gel while substrate topography assists the differentiation of hepatocyte-like cells in positive correlation with the circularity of H1 clones initially formed on the substrate. The differentiated cells exhibited liver-specific functions such as maintaining the capacities of CYP450 metabolism, glycogen synthesis, ICG engulfment, and repairing liver injury in CCl4-treated mice. These results implied that the coupling of substrate stiffness and topography, combined with the biochemical signals, is favorable to improve the efficiency and functionality of hepatic differentiation of human ESCs.


Asunto(s)
Células Madre Embrionarias Humanas , Animales , Diferenciación Celular , Células Cultivadas , Células Madre Embrionarias , Hígado , Ratones
18.
ACS Appl Mater Interfaces ; 13(15): 18294-18300, 2021 Apr 21.
Artículo en Inglés | MEDLINE | ID: mdl-33822573

RESUMEN

Current-induced spin-orbit torque (SOT) switching of magnetization has attracted great interest due to its potential application in magnetic memory devices, which offer low-energy consumption and high-speed writing. However, most of the SOT studies on perpendicularly magnetized anisotropy (PMA) magnets have been limited to heterostructures with interfacial PMA and poor thermal stability. Here, we experimentally demonstrate a SOT magnetization switching for a ferrimagnetic D022-Mn3Ge film with high bulk PMA and robust thermal stability factor under a critical current density of 6.6 × 1011 A m-2 through the spin Hall effect of an adjacent capping Pt and a buffer Cr layer. A large effective damping-like SOT efficiency of 2.37 mT/1010 A m-2 is determined using harmonic measurements in the structure. The effect of the double-spin source layers and the negative-exchange interaction of the ferrimagnet may explain the large SOT efficiency and the manifested magnetization switching of Mn3Ge. Our findings demonstrate that D022-Mn3Ge is a promising candidate for application in high-density SOT magnetic random-access memory devices.

19.
Nat Nanotechnol ; 16(3): 277-282, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33462431

RESUMEN

Modern magnetic-memory technology requires all-electric control of perpendicular magnetization with low energy consumption. While spin-orbit torque (SOT) in heavy metal/ferromagnet (HM/FM) heterostructures1-5 holds promise for applications in magnetic random access memory, until today, it has been limited to the in-plane direction. Such in-plane torque can switch perpendicular magnetization only deterministically with the help of additional symmetry breaking, for example, through the application of an external magnetic field2,4, an interlayer/exchange coupling6-9 or an asymmetric design10-14. Instead, an out-of-plane SOT15 could directly switch perpendicular magnetization. Here we observe an out-of-plane SOT in an HM/FM bilayer of L11-ordered CuPt/CoPt and demonstrate field-free switching of the perpendicular magnetization of the CoPt layer. The low-symmetry point group (3m1) at the CuPt/CoPt interface gives rise to this spin torque, hereinafter referred to as 3m torque, which strongly depends on the relative orientation of the current flow and the crystal symmetry. We observe a three-fold angular dependence in both the field-free switching and the current-induced out-of-plane effective field. Because of the intrinsic nature of the 3m torque, the field-free switching in CuPt/CoPt shows good endurance in cycling experiments. Experiments involving a wide variety of SOT bilayers with low-symmetry point groups16,17 at the interface may reveal further unconventional spin torques in the future.

20.
Phys Rev Lett ; 124(21): 217202, 2020 May 29.
Artículo en Inglés | MEDLINE | ID: mdl-32530667

RESUMEN

We report on the study of both perpendicular magnetic anisotropy (PMA) and Dzyaloshinskii-Moriya interaction (DMI) at an oxide/ferromagnetic metal (FM) interface, i.e., BaTiO_{3} (BTO)/CoFeB. Thanks to the functional properties of the BTO film and the capability to precisely control its growth, we are able to distinguish the dominant role of the oxide termination (TiO_{2} vs BaO) from the moderate effect of ferroelectric polarization in the BTO film, on the PMA and DMI at an oxide/FM interface. We find that the interfacial magnetic anisotropy energy of the BaO-BTO/CoFeB structure is 2 times larger than that of the TiO_{2}-BTO/CoFeB, while the DMI of the TiO_{2}-BTO/CoFeB interface is larger. We explain the observed phenomena by first principles calculations, which ascribe them to the different electronic states around the Fermi level at oxide/ferromagnetic metal interfaces and the different spin-flip process. This study paves the way for further investigation of the PMA and DMI at various oxide/FM structures and thus their applications in the promising field of energy-efficient devices.

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