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1.
Sci Total Environ ; 800: 149525, 2021 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-34392218

RESUMO

Recently, the extensive discharge of oily sludge, due to excessive use of fossil oil, has become a serious worldwide concern, as it leads to serious environmental pollution and even threat human health. However, the complex properties and compositions of oily sludge make it difficult for the treatment of oily sludge. This study proposed a novel method of combined degradation of oily sludge by surfactants with activated-persulfate, and analyzed the degradation efficiency and degradation pathway. The organics in oil sludge were eluted by surfactant, and the residual oil difficult to be eluted was further oxidized by activated persulfate. The combined method significantly improved the degradation efficiency of oily sludge, and the removal rate reached 94.6 ± 2.8%, and the oil content of the residual oily sludge was 0.57%, which had reached the discharge standard. The mechanism analysis indicated that surfactant could increase the solubility of oil by reducing the surface tension, and the hydroxyl radical and sulfate radical generated by activated persulfate could degrade the complex organic matters into small molecule matters, achieving efficient degradation of oil sludge. This work demonstrated a new avenue for the efficient and cost-effective treatment of oily sludge, opening an environmentally friendly treatment concept.


Assuntos
Esgotos , Tensoativos , Humanos , Radical Hidroxila , Óleos
2.
J Phys Chem Lett ; 12(34): 8220-8228, 2021 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-34415754

RESUMO

Two-dimensional piezoelectric materials have been regarded as ideal candidates for flexible and versatile nanoelectromechanical systems, yet their fundamental piezoelectric mechanisms remain to be fully understood. Employing joint theoretical-statistical analyses, we develop universal models for quantifying the piezoelectricity of three-coordinated honeycomb-like monolayers at the atomistic level. The theoretical model within the framework of modern polarization theory suggests that the distribution of effective Berry curvature is essential for interpreting the relation between microscopic/electronic structures and piezoelectric properties. The statistical model based on DFT high-throughput calculation reveals that 2D piezoelectricity crucially depends on the effective mass, bandgap, and atomic distance along the rotation axis. Implementing stress and doping is demonstrated to be effective for optimizing piezoelectricity. Such findings provide valuable guidelines for designing 2D piezoelectric materials.

3.
Drug Des Devel Ther ; 15: 2309-2324, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34103895

RESUMO

Introduction: The effect of 11ß-hydroxysteroid dehydrogenase type1 (11ß-HSD1) inhibition on hepatic steatosis is incompletely understood. Here, we aimed to determine the therapeutic effect of BVT.2733, a selective 11ß-HSD1 inhibitor, on hepatic steatosis. Materials and Methods: C57B/6J mice were randomly divided into a low-fat diet (LFD) fed group and a high-fat diet (HFD) fed group. Mice were fed with HFD for 28 weeks which induced obesity and severe hepatic steatosis. The two groups were further divided into four groups as follows: LFD, LFD with BVT.2733, HFD, and HFD with BVT.2733. Mice in LFD+BVT and HFD+BVT groups were intraperitoneally injected with BVT.2733 daily for 30 days. Effects of BVT.2733 on mice body weight, serum lipid profile, serum free fatty acids (FFAs), glucocorticoid levels, gene expression in adipose and liver tissues were assessed. Results: Injection of a low dose of BVT.2733 (50 mg/kg/day) reduced body weight and hyperlipidemia, but did not improve glucose tolerance and insulin resistance in diet-induced obese mice. The low dose of BVT.2733 attenuated hepatic steatosis, liver injury, and liver lipolytic gene expression in diet-induced obese mice. Besides, the low dose of BVT.2733 reduced fat mass and lipolysis in visceral adipose tissues, hepatic FFAs, and serum corticosterone levels in diet-induced obese mice. Conclusion: Our study shows that moderate inhibition of 11ß-HSD1 by BVT.2733 reduces FFAs and corticosterone synthesis in fatty tissues, thereby attenuates the delivery of corticosterone and FFAs to the liver. Collectively, this prevents high-fat diet-induced hepatic steatosis.

4.
Nano Lett ; 21(9): 4013-4020, 2021 05 12.
Artigo em Inglês | MEDLINE | ID: mdl-33900785

RESUMO

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.


Assuntos
Grafite , Cristalização , Semicondutores
5.
Nano Lett ; 21(9): 4099-4105, 2021 May 12.
Artigo em Inglês | MEDLINE | ID: mdl-33886320

RESUMO

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.

6.
Zhongguo Zhong Yao Za Zhi ; 46(5): 1191-1196, 2021 Mar.
Artigo em Chinês | MEDLINE | ID: mdl-33787114

RESUMO

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.


Assuntos
Colite Ulcerativa , Piroptose , Animais , Caspase 1/genética , Colite Ulcerativa/tratamento farmacológico , Camundongos , Proteína 3 que Contém Domínio de Pirina da Família NLR/genética , Scutellaria baicalensis
7.
Environ Technol ; : 1-7, 2021 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-33461434

RESUMO

In the process of handling marine oil spills accidents, the biological method has attracted wide attention due to its low cost and no secondary pollution. However, in the process of practical application, there are problems such as low microbial density and great influence of environmental factors when the oil is treated by spraying microorganisms on the sea surface. This study used immobilized microorganism technology to solve the above-mentioned problems. In this study, the bacteria immobilized on cinnamon shell (CS) with good degradation performance were obtained by optimizing preparation conditions. Under the optimal conditions of sodium alginate (SA) concentration of 4.57%, CS concentration of 1.28%, and the CaCl2 concentration of 2.45%, the degradation rate of diesel in 5 days reached 74.04%. The reusability of immobilized microbial agents was further studied. The study designed three cycles of repeated degradation experiments. The results showed that the degradation rate of diesel can still reach 60.12% after three times of reuse, which indicated the reusability of the immobilized microbial agents was excellent. The decrease in degradation rate of diesel was mainly related to the fragmentation of immobilized microbial agents and the decrease in microbial biomass.

8.
Rev Sci Instrum ; 91(11): 113103, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-33261447

RESUMO

This paper presents a new method for combined measurements of persistent luminescence (PersL), thermoluminescence (TL), and mechanoluminescence (ML) of luminescent materials in the micrometer scale. Both the hardware and software designs have been illustrated in detail, and the experimental procedures to execute the emission map, PersL, TL, and ML measurements have been demonstrated. The PersL, TL, and ML properties of the SrAl2O4:Eu2+, Dy3+ micropowder, as well as the corresponding temperature variable emission spectra, have been measured. The results show good agreement with published investigations, indicating the accomplishment of designed functions. The instrument would be a powerful tool for exploring phosphorescent materials in the micrometer and smaller scales.

9.
Zhongguo Zhong Yao Za Zhi ; 45(11): 2677-2686, 2020 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-32627503

RESUMO

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.


Assuntos
Colite Ulcerativa , Medicamentos de Ervas Chinesas , Biologia Computacional , Humanos , Medicina Tradicional Chinesa , Scutellaria baicalensis
10.
Sci Adv ; 6(17): eaaz5231, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32494645

RESUMO

Polycyclic heavy hydrocarbons (HHs) such as coal, tar, and pitch are a family of materials with extremely rich and complex chemistry, representing a massive opportunity for their use in a range of potential applications. The present work shows that optimal selection of initial HHs based on molecular constituents is essential in tuning the material for a particular and targeted electronic application. Combining the selection of feedstock chemistry (H:C and aromatic content) and controlling variable laser treatment parameters (laser power, speed, and focus) lead to full control over the H:C ratio, sp2 concentration, and degree of graphitic stacking order of the products. The broad intertunability of these factors results from a wide distribution of carbon material crystallinity from amorphous to highly graphitic and a broad distribution of electrical conductivity up to 103 S/m.

11.
Medicine (Baltimore) ; 99(17): e19659, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32332609

RESUMO

BACKGROUND: The number of citations a scientific paper has received indicates its impact within any medical field. We performed a bibliometric analysis to highlight the key topics of the most frequently cited 100 articles on perianal fistula to determine the advances in this field. METHODS: The Scopus database was searched from 1960 to 2018 using the search terms "perianal fistula" or "anal fistula" or "fistula in ano" or "anal fistulae" or "anorectal fistulae" including full articles. The topic, year of publication, publishing journal, country of origin, institution, and department of the first author were analyzed. RESULTS: The median number of citations for the top 100 of 3431 eligible papers, ranked in order of the number of citations, was 100 (range: 65-811), and the number of citations per year was 7.5 (range: 3.8-40.1). The most-cited paper (by Parks et al in 1976; 811citations) focused on the classification of perianal fistula. The institution with the highest number of publications was St Mark's Hospital, London, UK. The most-studied topic was surgical management (n = 47). The country and the decade with the greatest number of publications in this field were the USA (n = 34) and the 2000s (n = 50), respectively. CONCLUSION: The 100 most frequently cited manuscripts showed that surgical management had the greatest impact on the study of perianal fistula. This citation analysis provides a reference of what could be considered the most classic papers on perianal fistula, and may serve as a reference for researchers and clinicians as to what constitutes a citable paper in this field.


Assuntos
Bibliometria , Fístula Retal/epidemiologia , Fístula Retal/cirurgia , Humanos , Publicações Periódicas como Assunto
12.
J Vis Exp ; (155)2020 01 31.
Artigo em Inglês | MEDLINE | ID: mdl-32065148

RESUMO

The intestinal epithelium acts as a barrier that prevents luminal contents, such as pathogenic microbiota and toxins, from entering the rest of the body. Epithelial barrier function requires the integrity of intestinal epithelial cells. While epithelial cell proliferation maintains a continuous layer of cells that forms a barrier, epithelial damage leads to barrier dysfunction. As a result, luminal contents can across the intestinal barrier via an unrestricted pathway. Dysfunction of intestinal barrier has been associated with many intestinal diseases, such as inflammatory bowel disease. Isolated mouse intestinal crypts can be cultured and maintained as crypt-villus-like structures, which are termed intestinal organoids or "enteroids". Enteroids are ideal to study the proliferation and cell death of intestinal epithelial cells in vitro. In this protocol, we describe a simple method to quantify the number of proliferative and dead cells in cultured enteroids. 5-ethynyl-2'-deoxyuridine (EdU) and propidium iodide are used to label proliferating and dead cells in enteroids, and the proportion of proliferating and dead cells are then analyzed by flow cytometry. This is a useful tool to test the effects of drug treatment on intestinal epithelial cell proliferation and cell survival.


Assuntos
Mucosa Intestinal/metabolismo , Animais , Proliferação de Células , Citometria de Fluxo , Camundongos
13.
Nature ; 578(7793): 75-81, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-32025010

RESUMO

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.

14.
Nano Lett ; 19(12): 8388-8398, 2019 12 11.
Artigo em Inglês | MEDLINE | ID: mdl-31674187

RESUMO

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.

15.
Nat Commun ; 10(1): 4279, 2019 09 30.
Artigo em Inglês | MEDLINE | ID: mdl-31570710

RESUMO

Optical phase change materials (O-PCMs), a unique group of materials featuring exceptional optical property contrast upon a solid-state phase transition, have found widespread adoption in photonic applications such as switches, routers and reconfigurable meta-optics. Current O-PCMs, such as Ge-Sb-Te (GST), exhibit large contrast of both refractive index (Δn) and optical loss (Δk), simultaneously. The coupling of both optical properties fundamentally limits the performance of many applications. Here we introduce a new class of O-PCMs based on Ge-Sb-Se-Te (GSST) which breaks this traditional coupling. The optimized alloy, Ge2Sb2Se4Te1, combines broadband transparency (1-18.5 µm), large optical contrast (Δn = 2.0), and significantly improved glass forming ability, enabling an entirely new range of infrared and thermal photonic devices. We further demonstrate nonvolatile integrated optical switches with record low loss and large contrast ratio and an electrically-addressed spatial light modulator pixel, thereby validating its promise as a material for scalable nonvolatile photonics.

16.
Nat Med ; 25(4): 690-700, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30936544

RESUMO

Epithelial barrier loss is a driver of intestinal and systemic diseases. Myosin light chain kinase (MLCK) is a key effector of barrier dysfunction and a potential therapeutic target, but enzymatic inhibition has unacceptable toxicity. Here, we show that a unique domain within the MLCK splice variant MLCK1 directs perijunctional actomyosin ring (PAMR) recruitment. Using the domain structure and multiple screens, we identify a domain-binding small molecule (divertin) that blocks MLCK1 recruitment without inhibiting enzymatic function. Divertin blocks acute, tumor necrosis factor (TNF)-induced MLCK1 recruitment as well as downstream myosin light chain (MLC) phosphorylation, barrier loss, and diarrhea in vitro and in vivo. Divertin corrects barrier dysfunction and prevents disease development and progression in experimental inflammatory bowel disease. Beyond applications of divertin in gastrointestinal disease, this general approach to enzymatic inhibition by preventing access to specific subcellular sites provides a new paradigm for safely and precisely targeting individual properties of enzymes with multiple functions.


Assuntos
Homeostase , Mucosa Intestinal/metabolismo , Espaço Intracelular/enzimologia , Quinase de Cadeia Leve de Miosina/metabolismo , Actomiosina/metabolismo , Animais , Células CACO-2 , Doença Crônica , Homeostase/efeitos dos fármacos , Humanos , Inflamação/patologia , Doenças Inflamatórias Intestinais/patologia , Mucosa Intestinal/efeitos dos fármacos , Jejuno/efeitos dos fármacos , Jejuno/metabolismo , Jejuno/patologia , Camundongos , Cadeias Leves de Miosina/metabolismo , Quinase de Cadeia Leve de Miosina/química , Fosforilação/efeitos dos fármacos , Domínios Proteicos , Bibliotecas de Moléculas Pequenas/farmacologia , Junções Íntimas/efeitos dos fármacos , Junções Íntimas/metabolismo , Fator de Necrose Tumoral alfa/farmacologia
17.
Cell Mol Gastroenterol Hepatol ; 7(2): 255-274, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30686779

RESUMO

BACKGROUND & AIMS: Epithelial regeneration is essential for homeostasis and repair of the mucosal barrier. In the context of infectious and immune-mediated intestinal disease, interleukin (IL) 22 is thought to augment these processes. We sought to define the mechanisms by which IL22 promotes mucosal healing. METHODS: Intestinal stem cell cultures and mice were treated with recombinant IL22. Cell proliferation, death, and differentiation were assessed in vitro and in vivo by morphometric analysis, quantitative reverse transcriptase polymerase chain reaction, and immunohistochemistry. RESULTS: IL22 increased the size and number of proliferating cells within enteroids but decreased the total number of enteroids. Enteroid size increases required IL22-dependent up-regulation of the tight junction cation and water channel claudin-2, indicating that enteroid enlargement reflected paracellular flux-induced swelling. However, claudin-2 did not contribute to IL22-dependent enteroid loss, depletion of Lgr5+ stem cells, or increased epithelial proliferation. IL22 induced stem cell apoptosis but, conversely, enhanced proliferation within and expanded numbers of transit-amplifying cells. These changes were associated with reduced wnt and notch signaling, both in vitro and in vivo, as well as skewing of epithelial differentiation, with increases in Paneth cells and reduced numbers of enteroendocrine cells. CONCLUSIONS: IL22 promotes transit-amplifying cell proliferation but reduces Lgr5+ stem cell survival by inhibiting notch and wnt signaling. IL22 can therefore promote or inhibit mucosal repair, depending on whether effects on transit-amplifying or stem cells predominate. These data may explain why mucosal healing is difficult to achieve in some inflammatory bowel disease patients despite markedly elevated IL22 production.


Assuntos
Interleucinas/farmacologia , Receptores Acoplados a Proteínas G/metabolismo , Receptores Notch/metabolismo , Células-Tronco/citologia , Células-Tronco/metabolismo , Via de Sinalização Wnt/efeitos dos fármacos , Animais , Apoptose/efeitos dos fármacos , Biomarcadores/metabolismo , Contagem de Células , Diferenciação Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Claudina-2/metabolismo , Enterócitos/citologia , Enterócitos/efeitos dos fármacos , Enterócitos/metabolismo , Intestinos/citologia , Camundongos , Camundongos Endogâmicos C57BL , Organoides/metabolismo , Células-Tronco/efeitos dos fármacos , Regulação para Cima/efeitos dos fármacos
18.
J Vis Exp ; (140)2018 10 19.
Artigo em Inglês | MEDLINE | ID: mdl-30394372

RESUMO

The intestinal barrier defends against pathogenic microorganism and microbial toxin. Its function is regulated by tight junction permeability and epithelial cell integrity, and disruption of the intestinal barrier function contributes to progression of gastrointestinal and systemic disease. Two simple methods are described here to measure the permeability of intestinal epithelium. In vitro, Caco-2BBe cells are plated in tissue culture wells as a monolayer and transepithelial electrical resistance (TER) can be measured by an epithelial (volt/ohm) meter. This method is convincing because of its user-friendly operation and repeatability. In vivo, mice are gavaged with 4 kDa fluorescein isothiocyanate (FITC)-dextran, and the FITC-dextran concentrations are measured in collected serum samples from mice to determine the epithelial permeability. Oral gavage provides an accurate dose, and therefore is the preferred method to measure the intestinal permeability in vivo. Taken together, these two methods can measure the permeability of the intestinal epithelium in vitro and in vivo, and hence be used to study the connection between diseases and barrier function.


Assuntos
Células Epiteliais/química , Mucosa Intestinal/química , Animais , Humanos , Mucosa Intestinal/patologia , Camundongos , Permeabilidade
19.
Nat Mater ; 17(11): 999-1004, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30297812

RESUMO

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.

20.
ACS Nano ; 12(8): 7721-7730, 2018 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-30117727

RESUMO

High-energy irradiation of materials can lead to void formation due to the aggregation of vacancies, reducing the local stress in the system. Studying void formation and its interplay with vacancy clusters in bulk materials at the atomic level has been challenging due to the thick volume of 3D materials, which generally limits high-resolution transmission electron microscopy. The thin nature of 2D materials is ideal for studying fundamental material defects such as dislocations and crack tips and has potential to reveal void formation by vacancy aggregation in detail. Here, using atomic-resolution in situ transmission electron microscopy of 2D monolayer MoS2, we capture rapid thermal diffusion of S vacancies into ultralong (∼60 nm) 1D S vacancy channels that initiate void formation at high vacancy densities. Strong interactions are observed between the 1D channels and void growth, whereby Mo and S atoms are funneled back and forth between the void edge and the crystal surface to enable void enlargement. Preferential void growth up to 100 nm is shown to occur by rapid digestion of 1D S vacancy channels as they make contact. These results reveal the atomistic mechanisms behind void enlargement in 2D materials under intense high-energy irradiation at high temperatures and the existence of ultralong 1D vacancy channels. This knowledge may also help improve the understanding of void formation in other systems such as nuclear materials, where direct visualization is challenging due to 3D bulk volume.

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