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1.
Nature ; 578(7793): 75-81, 2020 02.
Artículo en Inglés | MEDLINE | ID: mdl-32025010

RESUMEN

Complex-oxide materials exhibit a vast range of functional properties desirable for next-generation electronic, spintronic, magnetoelectric, neuromorphic, and energy conversion storage devices1-4. Their physical functionalities can be coupled by stacking layers of such materials to create heterostructures and can be further boosted by applying strain5-7. The predominant method for heterogeneous integration and application of strain has been through heteroepitaxy, which drastically limits the possible material combinations and the ability to integrate complex oxides with mature semiconductor technologies. Moreover, key physical properties of complex-oxide thin films, such as piezoelectricity and magnetostriction, are severely reduced by the substrate clamping effect. Here we demonstrate a universal mechanical exfoliation method of producing freestanding single-crystalline membranes made from a wide range of complex-oxide materials including perovskite, spinel and garnet crystal structures with varying crystallographic orientations. In addition, we create artificial heterostructures and hybridize their physical properties by directly stacking such freestanding membranes with different crystal structures and orientations, which is not possible using conventional methods. Our results establish a platform for stacking and coupling three-dimensional structures, akin to two-dimensional material-based heterostructures, for enhancing device functionalities8,9.

2.
Nano Lett ; 24(4): 1137-1144, 2024 Jan 31.
Artículo en Inglés | MEDLINE | ID: mdl-38252462

RESUMEN

Piezoelectricity has been widely explored for nanoelectromechanical applications, yet its working modes are mainly limited in polar directions. Here we discover the intrinsic electro-mechanical response in crystal materials that is transverse to the conventional polarized direction, which is named unconventional piezoelectricity. A Hall-like mechanism is proposed to interpret unconventional piezoelectricity as charge polarization driven by a built-in electric field for systems with asymmetric Berry curvature distributions. Density functional theory simulations and statistical analyses justify such a mechanism and confirm that unconventional piezoelectricity is a general property for various two-dimensional materials with spin splitting or valley splitting. An empirical formula is derived to connect the conventional and unconventional piezoelectricity. The extended understanding of the piezoelectric tensor in quantum materials opens an opportunity for applications in multidirectional energy conversion, broadband operation, and multifunctional sensing.

3.
Nano Lett ; 21(9): 4099-4105, 2021 May 12.
Artículo en Inglés | MEDLINE | ID: mdl-33886320

RESUMEN

Magnetoelectrics are witnessing an ever-growing success toward the voltage-controlled magnetism derived from inorganic materials. However, these inorganic materials have predominantly focused on the ferroelectromagnetism at solid-to-solid interfaces and suffered several drawbacks, including the interface-sensitive coupling mediators, high-power electric field, and limited chemical tunability. Here, we report a promising design strategy to shift the paradigm of next-generation molecular magnetoelectrics, which relies on the integration between molecular magnetism and electric conductivity though an in situ cross-linking strategy. Following this approach, we demonstrate a versatile and efficient synthesis of flexible molecular-based magnetoelectronics by cross-linking of magnetic coordination networks that incorporate conducting chain building blocks. The as-grown compounds feature an improved critical temperature up to 337 K and a room-temperature magnetism control of low-power electric field. It is envisaged that the cross-linking of molecular interfaces is a feasible method to couple and modulate magnetism and electron conducting systems.

4.
Nano Lett ; 21(9): 4013-4020, 2021 05 12.
Artículo en Inglés | MEDLINE | ID: mdl-33900785

RESUMEN

Free-standing crystalline membranes are highly desirable owing to recent developments in heterogeneous integration of dissimilar materials. Van der Waals (vdW) epitaxy enables the release of crystalline membranes from their substrates. However, suppressed nucleation density due to low surface energy has been a challenge for crystallization; reactive materials synthesis environments can induce detrimental damage to vdW surfaces, often leading to failures in membrane release. This work demonstrates a novel platform based on graphitized SiC for fabricating high-quality free-standing membranes. After mechanically removing epitaxial graphene on a graphitized SiC wafer, the quasi-two-dimensional graphene buffer layer (GBL) surface remains intact for epitaxial growth. The reduced vdW gap between the epilayer and substrate enhances epitaxial interaction, promoting remote epitaxy. Significantly improved nucleation and convergent quality of GaN are achieved on the GBL, resulting in the best quality GaN ever grown on two-dimensional materials. The GBL surface exhibits excellent resistance to harsh growth environments, enabling substrate reuse by repeated growth and exfoliation.


Asunto(s)
Grafito , Cristalización , Semiconductores
5.
Zhongguo Zhong Yao Za Zhi ; 46(5): 1191-1196, 2021 Mar.
Artículo en Zh | MEDLINE | ID: mdl-33787114

RESUMEN

To explore the effect of Huangqin Decoction on ulcerative colitis(UC) pyroptosis, and to explain the mechanism of pyroptosis based on NOD-like receptor thermoprotein domain 3(NLRP3)/cysteine proteinase 1(caspase-1) pathway. The animal model of UC induced with 3% dextran sodium sulfate(DSS) was established. The experimental animals were divided into control group, model group, low-dose(4.55 g·kg~(-1)), medium-dose(9.1 g·kg~(-1)) and high-dose(18.2 g·kg~(-1)) Huangqin Decoction groups and salazosulfapyridine group(0.45 g·kg~(-1)). While modeling, intragastric administration was given for 7 consecutive days. On the 8 th day, the mice were euthanized, the colon length was collected, and the histopathological changes were observed by HE staining. The content of interleukin-18(IL-18) was observed by ELISA. The content of lactatedehydrogenase(LDH)was determined by microplate method. TUNEL assay kit was used to detect the cell death. The immunohistochemical staining was used to detect the expressions of NLRP3 and apoptosis-associated speck-like protein containing a CARD(ASC). Western blot was used to detect the expressions of interleukin-1ß(IL-1ß), caspase-1 and gasdermin D(GSDMD).The experimental study showed that compared with normal group, the LDH content, TUNEL positive staining, inflammatory factors(IL-18, IL-1ß), and proteins associated with pyroptosis were significantly increased(P<0.05). Compared with model control group, the LDH content, TUNEL positive staining, inflammatory factors(IL-18, IL-1ß), and proteins associated with pyroptosis were decreased, and these results were more significant in high-dose groups(P<0.05). The results of HE staining showed that Huangqin Decoction could improve the pathological changes of colon. Huangqin Decoction could inhibit UC cell pyroptosis, and the mechanism may be closely related to NLRP3/caspase-1 signaling pathway.


Asunto(s)
Colitis Ulcerosa , Piroptosis , Animales , Caspasa 1/genética , Colitis Ulcerosa/tratamiento farmacológico , Ratones , Proteína con Dominio Pirina 3 de la Familia NLR/genética , Scutellaria baicalensis
6.
Proc Natl Acad Sci U S A ; 114(33): 8693-8697, 2017 08 15.
Artículo en Inglés | MEDLINE | ID: mdl-28760988

RESUMEN

Controlling the flow of thermal energy is crucial to numerous applications ranging from microelectronic devices to energy storage and energy conversion devices. Here, we report ultralow lattice thermal conductivities of solution-synthesized, single-crystalline all-inorganic halide perovskite nanowires composed of CsPbI3 (0.45 ± 0.05 W·m-1·K-1), CsPbBr3 (0.42 ± 0.04 W·m-1·K-1), and CsSnI3 (0.38 ± 0.04 W·m-1·K-1). We attribute this ultralow thermal conductivity to the cluster rattling mechanism, wherein strong optical-acoustic phonon scatterings are driven by a mixture of 0D/1D/2D collective motions. Remarkably, CsSnI3 possesses a rare combination of ultralow thermal conductivity, high electrical conductivity (282 S·cm-1), and high hole mobility (394 cm2·V-1·s-1). The unique thermal transport properties in all-inorganic halide perovskites hold promise for diverse applications such as phononic and thermoelectric devices. Furthermore, the insights obtained from this work suggest an opportunity to discover low thermal conductivity materials among unexplored inorganic crystals beyond caged and layered structures.

7.
Nano Lett ; 19(12): 8388-8398, 2019 12 11.
Artículo en Inglés | MEDLINE | ID: mdl-31674187

RESUMEN

Rational control of nanoparticle (NP) size distribution during operation is crucial to improve catalytic performance and noble metal sustainability. Herein, we explore the Ostwald ripening (OR) of metal atoms on zeolite surfaces by a coupled theoretical-experimental approach. Zeolites with the same structure (ZSM-5) but different concentrations of aluminum doped into the matrix were observed to yield systematic differences in supported nanoparticle size distributions. Our first-principles simulations suggest that NP stability at high temperature is governed by both geometric constraints and the roughness of the energetic landscape. Calculated adatom migration paths across the zeolite surface and desorption paths from the supported NPs lend insight into the modified OR sintering processes with the emergence of different binding configurations as the aluminum concentration increases from pristine to heavily doped ZSM-5. These findings reveal the potential for the rational design of support structures to suppress OR sintering.

8.
Zhongguo Zhong Yao Za Zhi ; 45(11): 2677-2686, 2020 Jun.
Artículo en Zh | MEDLINE | ID: mdl-32627503

RESUMEN

Data GSE75214 and GSE48959 that contained ulcerative colitis(UC) in the active stage was download from GEO database. Differential genes of UC in the active phase were obtained by using adjusted P<0.05 and |log_2 FC|≥1.5, which was the screening criteria. PPI analysis was performed in the STRING database, and GO and KEGG pathway analysis was performed in DAVID database. Cytoscape was used to visualize differential genes, and calculate key genes in the active phase. Coremine Medical was used to analyze and systematically evaluate traditional Chinese medicines for treating key genes. Finally, 139 differentially expressed genes in the active phase were screened out, which included the 109 up-regulated genes and 30 down-regulated genes. DAVID analyzed that the biology and pathways of these differential genes were mainly concentrated in inflammatory response, immune response, chemokine activity, TNF pathway, NF-κB pathway, and Toll-like receptor pathway. Cytoscape software calculated that IL-6, CXCL8, IL-1ß, MMP9, CXCL1, ICAM1, CXCL10, TIMP1, PTGS2 and CXCL9 were the key genes of UC in the active phase. According to Coremine Medical analysis, traditional Chinese medicines for UC in the active stage included Curcumae Longae Rhizoma, Scutellariae Radix, Curcumae Radix had clearing heat clearing damp, reducing fire and detoxifying effects, which was in line with the pathogenesis of UC active stage, and was often used in clinical treatment of dampness-heat diarrhea. Therefore, Huangqin Decoction, which Scutellariae Radix was the principal drug, was selected for systematic evaluation. The evaluation showed that Scutellariae Radix was superior to Western medicine in terms of improving clinical efficiency, reducing inflammatory factors and immunoglobulin levels, with statistically significant differences and fewer adverse reactions. This study provided a new idea for further research on the pathogenesis of UC in the active phase by analyzing the genes and their mechanism of action, and the systematic evaluation of Chinese medicine for the treatment of UC active stage provided a basis for the clinical prevention and treatment of UC by Chinese medicine.


Asunto(s)
Colitis Ulcerosa , Medicamentos Herbarios Chinos , Biología Computacional , Humanos , Medicina Tradicional China , Scutellaria baicalensis
9.
Nat Mater ; 17(11): 999-1004, 2018 11.
Artículo en Inglés | MEDLINE | ID: mdl-30297812

RESUMEN

The transparency of two-dimensional (2D) materials to intermolecular interactions of crystalline materials has been an unresolved topic. Here we report that remote atomic interaction through 2D materials is governed by the binding nature, that is, the polarity of atomic bonds, both in the underlying substrates and in 2D material interlayers. Although the potential field from covalent-bonded materials is screened by a monolayer of graphene, that from ionic-bonded materials is strong enough to penetrate through a few layers of graphene. Such field penetration is substantially attenuated by 2D hexagonal boron nitride, which itself has polarization in its atomic bonds. Based on the control of transparency, modulated by the nature of materials as well as interlayer thickness, various types of single-crystalline materials across the periodic table can be epitaxially grown on 2D material-coated substrates. The epitaxial films can subsequently be released as free-standing membranes, which provides unique opportunities for the heterointegration of arbitrary single-crystalline thin films in functional applications.

10.
Nano Lett ; 18(7): 4346-4354, 2018 07 11.
Artículo en Inglés | MEDLINE | ID: mdl-29856639

RESUMEN

Wearable conformal electronics are essential components for next-generation humanlike sensing devices that can accurately respond to external stimuli in nonplanar and dynamic surfaces. However, to explore this potential, it is indispensable to achieve the desired level of deformability and charge-transport mobility in strain-accommodating soft semiconductors. Here, we show pseudo-two-dimensional freestanding conjugated polymer heterojunction nanosheets integrated into substrate-free conformal electronics owing to their exceptional crystalline controlled charge transport and high level of mechanical strength. These freestanding and mechanical robust polymer nanosheets can be adapted into a variety of artificial structured surfaces such as fibers, squares, circles, etc., which produce large-area stretchable conformal charge-transfer sensors for real-time static and dynamic monitoring.

11.
Nano Lett ; 17(9): 5502-5507, 2017 09 13.
Artículo en Inglés | MEDLINE | ID: mdl-28799770

RESUMEN

The edges of 2D materials show novel electronic, magnetic, and optical properties, especially when reduced to nanoribbon widths. Therefore, methods to create atomically flat edges in 2D materials are essential for future exploitation. Atomically flat edges in 2D materials are found after brittle fracture or when electrically biasing, but a simple scalable approach for creating atomically flat periodic edges in monolayer 2D transition metal dichalcogenides has yet to be realized. Here, we show how heating monolayer MoS2 to 800 °C in vacuum produces atomically flat Mo terminated zigzag edges in nanoribbons. We study this at the atomic level using an ultrastable in situ heating holder in an aberration-corrected transmission electron microscope and discriminating Mo from S at the edge, revealing unique Mo terminations for all zigzag orientations that remain stable and atomically flat when cooling back to room temperature. Highly faceted MoS2 nanoribbon constrictions are produced with Mo rich edge structures that have theoretically predicted spin separated transport channels, which are promising for spin logic applications.

12.
Nano Lett ; 16(4): 2851-9, 2016 Apr 13.
Artículo en Inglés | MEDLINE | ID: mdl-26999430

RESUMEN

Organic charge-transfer superstructures are enabling new interfacial electronics, such as organic thermoelectrics, spin-charge converters, and solar cells. These carbon-based materials could also play an important role in spin-based electronics due to their exceptionally long spin lifetime. However, to explore these potentials a coherent design strategy to control interfacial charge-transfer interaction is indispensable. Here we report that the control of organic crystallization and interfacial electron coupling are keys to dictate external stimuli responsive behaviors in organic charge-transfer superstructures. The integrated experimental and computational study reveals the importance of chemically driven interfacial coupling in organic charge-transfer superstructures. Such degree of engineering opens up a new route to develop a new generation of functional charge-transfer materials, enabling important advance in all organic interfacial electronics.

13.
Nano Lett ; 15(6): 3657-63, 2015 Jun 10.
Artículo en Inglés | MEDLINE | ID: mdl-25971956

RESUMEN

The quantum confinement and enhanced optical properties of silicon quantum dots (SiQDs) make them attractive as an inexpensive and nontoxic material for a variety of applications such as light emitting technologies (lighting, displays, sensors) and photovoltaics. However, experimental demonstration of these properties and practical application into optoelectronic devices have been limited as SiQDs are generally passivated with covalently bound insulating alkyl chains that limit charge transport. In this work, we show that strategically designed triphenylamine-based surface ligands covalently bonded to the SiQD surface using conjugated vinyl connectivity results in a 70 nm red-shifted photoluminescence relative to their decyl-capped control counterparts. This suggests that electron density from the SiQD is delocalized into the surface ligands to effectively create a larger hybrid QD with possible macroscopic charge transport properties.

14.
Yi Chuan ; 37(10): 974-82, 2015 10.
Artículo en Inglés | MEDLINE | ID: mdl-26496749

RESUMEN

CRISPR/Cas system is an adaptive immune system that confers resistance to exogenous virus or plasmid in bacteria and archaea. In recent years, the booming CRISPR/Cas9 genome editing technology modified from type2 CRISPR/Cas adaptive immune system has been widely applied to various research fields of life science and led to revolutionary changes. In this review, we summarize the origin and development of CRISPR/Cas9 genome editing technology as well as its applications in life science research. We focus on the latest application of this system in gene therapy of human diseases and the associated side/off-target effects, which may provide references for researchers in related areas.


Asunto(s)
Inmunidad Adaptativa/genética , Sistemas CRISPR-Cas , Ingeniería Genética/métodos , Terapia Genética/métodos , Endonucleasas/genética , Endonucleasas/metabolismo , Ingeniería Genética/tendencias , Terapia Genética/tendencias , Infecciones por VIH/genética , Infecciones por VIH/inmunología , Infecciones por VIH/terapia , Humanos , Modelos Genéticos , Neoplasias/genética , Neoplasias/inmunología , Neoplasias/terapia , ARN Guía de Kinetoplastida/genética , ARN Guía de Kinetoplastida/metabolismo
15.
Phys Chem Chem Phys ; 16(36): 19275-81, 2014 Sep 28.
Artículo en Inglés | MEDLINE | ID: mdl-25098607

RESUMEN

The absorption of photons through the direct generation of spatially separated excitons at dot-ligand interfaces is proposed as a promising strategy for tailoring the optical gap of small silicon quantum dots independent of their size. This removes a primary drawback for the use of very small dots in broad range of applications. For instance, the strategy can be applied to solar energy technologies to align the absorption of such dots with the peak of the solar spectrum. The key is to establish both a Type-II energy level alignment and a strong electronic coupling between the dot and ligand. Our first principles analysis indicates that connecting conjugated organic ligands to silicon quantum dots using vinyl connectivity can satisfy both requirements. For a prototype assembly of 2.6 nm dots, we predict that triphenylamine termination will result in a 0.47 eV redshift along with an enhanced near-edge absorption character. Robustness analyses of the influence of oxidation on absorption and of extra alkyl ligands reveal that the control of both factors is important in practical applications.


Asunto(s)
Puntos Cuánticos , Silicio/química , Tamaño de la Partícula
16.
J Chem Phys ; 141(15): 154701, 2014 Oct 21.
Artículo en Inglés | MEDLINE | ID: mdl-25338905

RESUMEN

The universal and fundamental criteria for charge separation at interfaces involving nanoscale materials are investigated. In addition to the single-quasiparticle excitation, all the two-quasiparticle effects including exciton binding, Coulomb stabilization, and exciton transfer are considered, which play critical roles on nanoscale interfaces for optoelectronic applications. We propose a scheme allowing adding these two-quasiparticle interactions on top of the single-quasiparticle energy level alignment for determining and illuminating charge separation at nanoscale interfaces. Employing the many-body perturbation theory based on Green's functions, we quantitatively demonstrate that neglecting or simplifying these crucial two-quasiparticle interactions using less accurate methods is likely to predict qualitatively incorrect charge separation behaviors at nanoscale interfaces where quantum confinement dominates.

17.
ScientificWorldJournal ; 2014: 128754, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-24605046

RESUMEN

Since air temperature records are readily available around the world, the models based on air temperature for estimating solar radiation have been widely accepted. In this paper, a new model based on Hargreaves and Samani (HS) method for estimating monthly average daily global solar radiation is proposed. With statistical error tests, the performance of the new model is validated by comparing with the HS model and its two modifications (Samani model and Chen model) against the measured data at 65 meteorological stations in China. Results show that the new model is more accurate and robust than the HS, Samani, and Chen models in all climatic regions, especially in the humid regions. Hence, the new model can be recommended for estimating solar radiation in areas where only air temperature data are available in China.


Asunto(s)
Modelos Teóricos , Luz Solar , China
18.
J Genet Genomics ; 51(1): 61-74, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37328030

RESUMEN

Thyroid-stimulating hormone (TSH) is important for the thyroid gland, development, growth, and metabolism. Defects in TSH production or the thyrotrope cells within the pituitary gland cause congenital hypothyroidism (CH), resulting in growth retardation and neurocognitive impairment. While human TSH is known to display rhythmicity, the molecular mechanisms underlying the circadian regulation of TSH and the effects of TSH-thyroid hormone (TH) signaling on the circadian clock remain elusive. Here we show that TSH, thyroxine (T4), triiodothyronine (T3), and tshba display rhythmicity in both larval and adult zebrafish and tshba is regulated directly by the circadian clock via both E'-box and D-box. Zebrafish tshba-/- mutants manifest congenital hypothyroidism, with the characteristics of low levels of T4 and T3 and growth retardation. Loss or overexpression of tshba alters the rhythmicity of locomotor activities and expression of core circadian clock genes and hypothalamic-pituitary-thyroid (HPT) axis-related genes. Furthermore, TSH-TH signaling regulates clock2/npas2 via the thyroid response element (TRE) in its promoter, and transcriptome analysis reveals extensive functions of Tshba in zebrafish. Together, our results demonstrate that zebrafish tshba is a direct target of the circadian clock and in turn plays critical roles in circadian regulation along with other functions.


Asunto(s)
Hipotiroidismo Congénito , Tirotropina , Animales , Adulto , Humanos , Pez Cebra/genética , Pez Cebra/metabolismo , Triyodotironina/metabolismo , Trastornos del Crecimiento
19.
J Gastrointestin Liver Dis ; 33(2): 269-277, 2024 Jun 29.
Artículo en Inglés | MEDLINE | ID: mdl-38944855

RESUMEN

Colorectal cancer is a prevalent malignancy, with advanced and metastatic forms exhibiting poor treatment outcomes and high relapse rates. To enhance patient outcomes, a comprehensive understanding of the pathophysiological processes and the development of targeted therapies are imperative. The high heterogeneity of colorectal cancer demands precise and personalized treatment strategies. Colorectal cancer organoids, a three-dimensional in vitro model, have emerged as a valuable tool for replicating tumor biology and exhibit promise in scientific research, disease modeling, drug screening, and personalized medicine. In this review, we present an overview of colorectal cancer organoids and explore their applications in research and personalized medicine, while also discussing potential future developments in this field.


Asunto(s)
Neoplasias Colorrectales , Organoides , Medicina de Precisión , Humanos , Organoides/patología , Neoplasias Colorrectales/patología , Neoplasias Colorrectales/terapia , Animales
20.
Int J Womens Health ; 16: 783-795, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38737496

RESUMEN

Objective: This cross-sectional study aimed to explore the association of overweight and inflammatory indicators with breast cancer risk in Chinese patients. Methods: Weight, height, and peripheral blood inflammatory indicators, including white blood cell count (WBC), neutrophil count (NE), lymphocyte count (LY), platelet count (PLT) and the concentration of hypersensitivity C-reactive protein (hsCRP), were collected in 383 patients with benign breast lumps (non-cancer) and 358 patients with malignant breast tumors (cancer) at the First Affiliated Hospital of Soochow University, China, from March 2018 to July 2020. Body mass index (BMI), neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR) and systemic immune-inflammation index (SII) were determined according to the ratio equation. The correlations among overweight, inflammatory indicators, and the proportion of non-cancer or cancer cases were analyzed. Results: BMI is associated with an increased breast cancer risk. Compared with non-cancer patients, the average WBC count, NE count, NLR, and level of hsCRP were significantly higher in cancer patients. The level of hsCRP was closely associated with the size of malignant breast tumors. Conclusion: We conclude that overweight and high levels of hsCRP may serve as putative risk factors for malignant breast tumors in Chinese women.

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