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1.
Sensors (Basel) ; 23(23)2023 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-38067890

RESUMO

Spatial navigation patterns in indoor space usage can reveal important cues about the cognitive health of participants. In this work, we present a low-cost, scalable, open-source edge computing system using Bluetooth low energy (BLE) beacons for tracking indoor movements in a large, 1700 m2 facility used to carry out therapeutic activities for participants with mild cognitive impairment (MCI). The facility is instrumented with 39 edge computing systems, along with an on-premise fog server. The participants carry a BLE beacon, in which BLE signals are received and analyzed by the edge computing systems. Edge computing systems are sparsely distributed in the wide, complex indoor space, challenging the standard trilateration technique for localizing subjects, which assumes a dense installation of BLE beacons. We propose a graph trilateration approach that considers the temporal density of hits from the BLE beacon to surrounding edge devices to handle the inconsistent coverage of edge devices. This proposed method helps us tackle the varying signal strength, which leads to intermittent detection of beacons. The proposed method can pinpoint the positions of multiple participants with an average error of 4.4 m and over 85% accuracy in region-level localization across the entire study area. Our experimental results, evaluated in a clinical environment, suggest that an ordinary medical facility can be transformed into a smart space that enables automatic assessment of individuals' movements, which may reflect health status or response to treatment.


Assuntos
Computação em Nuvem , Navegação Espacial , Humanos , Tecnologia sem Fio , Nível de Saúde , Movimento , Navegação Espacial/fisiologia
2.
Hum Mutat ; 40(2): 142-161, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30461124

RESUMO

The epithelial cell adhesion molecule gene (EPCAM, previously known as TACSTD1 or TROP1) encodes a membrane-bound protein that is localized to the basolateral membrane of epithelial cells and is overexpressed in some tumors. Biallelic mutations in EPCAM cause congenital tufting enteropathy (CTE), which is a rare chronic diarrheal disorder presenting in infancy. Monoallelic deletions of the 3' end of EPCAM that silence the downstream gene, MSH2, cause a form of Lynch syndrome, which is a cancer predisposition syndrome associated with loss of DNA mismatch repair. Here, we report 13 novel EPCAM mutations from 17 CTE patients from two separate centers, review EPCAM mutations associated with CTE and Lynch syndrome, and structurally model pathogenic missense mutations. Statistical analyses indicate that the c.499dupC (previously reported as c.498insC) frameshift mutation was associated with more severe treatment regimens and greater mortality in CTE, whereas the c.556-14A>G and c.491+1G>A splice site mutations were not correlated with treatments or outcomes significantly different than random simulation. These findings suggest that genotype-phenotype correlations may be useful in contributing to management decisions of CTE patients. Depending on the type and nature of EPCAM mutation, one of two unrelated diseases may occur, CTE or Lynch syndrome.


Assuntos
Neoplasias Colorretais Hereditárias sem Polipose/genética , Diarreia Infantil/genética , Molécula de Adesão da Célula Epitelial/química , Síndromes de Malabsorção/genética , Modelos Moleculares , Neoplasias Colorretais Hereditárias sem Polipose/patologia , Diarreia Infantil/patologia , Molécula de Adesão da Célula Epitelial/genética , Células Epiteliais/metabolismo , Estudos de Associação Genética , Humanos , Síndromes de Malabsorção/patologia , Proteína 2 Homóloga a MutS/genética , Mutação de Sentido Incorreto/genética , Sítios de Splice de RNA/genética
3.
Am J Physiol Gastrointest Liver Physiol ; 317(5): G580-G591, 2019 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-31433211

RESUMO

Congenital tufting enteropathy (CTE) is an autosomal recessive disease characterized by severe intestinal failure in infancy and mutations in the epithelial cell adhesion molecule (EPCAM) gene. Previous studies of CTE in mice expressing mutant EpCAM show neonatal lethality. Hence, to study the cellular, molecular, and physiological alterations that result from EpCAM mutation, a tamoxifen-inducible mutant EpCAM enteroid model has been generated. The presence of mutant EpCAM in the model was confirmed at both mRNA and protein levels. Immunofluorescence microscopy demonstrated the reduced expression of mutant EpCAM. Mutant enteroids had reduced budding potential as well as significantly decreased mRNA expression for epithelial lineage markers (Mucin 2, lysozyme, sucrase-isomaltase), proliferation marker Ki67, and secretory pathway transcription factors (Atoh1, Hnf1b). Significantly decreased numbers of Paneth and goblet cells were confirmed by staining. These findings were correlated with intestinal tissue from CTE patients and the mutant mice model that had significantly fewer Paneth and goblet cells than in healthy counterparts. FITC-dextran studies demonstrated significantly impaired barrier function in monolayers derived from mutant enteroids compared with control monolayers. In conclusion, we have established an ex vivo CTE model. The role of EpCAM in the budding potential, differentiation, and barrier function of enteroids is noted. Our study establishes new facets of EpCAM biology that will aid in understanding the pathophysiology of CTE and role of EpCAM in health and disease.NEW & NOTEWORTHY Here, we develop a novel ex vivo enteroid model for congenital tufting enteropathy (CTE) based on epithelial cell adhesion molecule (EPCAM) gene mutations found in patients. With this model we demonstrate the role of EpCAM in maintaining the functional homeostasis of the intestinal epithelium, including differentiation, proliferation, and barrier integrity. This study further establishes a new direction in EpCAM biology that will help in understanding the detailed pathophysiology of CTE and role of EpCAM.


Assuntos
Diarreia Infantil/genética , Molécula de Adesão da Célula Epitelial/genética , Mucosa Intestinal/citologia , Síndromes de Malabsorção/genética , Técnicas de Cultura de Tecidos/métodos , Animais , Diferenciação Celular , Proliferação de Células , Células Cultivadas , Diarreia Infantil/patologia , Molécula de Adesão da Célula Epitelial/metabolismo , Feminino , Células Caliciformes/citologia , Células Caliciformes/metabolismo , Células Caliciformes/fisiologia , Mucosa Intestinal/metabolismo , Mucosa Intestinal/patologia , Síndromes de Malabsorção/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Celulas de Paneth/citologia , Celulas de Paneth/metabolismo , Celulas de Paneth/fisiologia
4.
Inorg Chem ; 54(3): 1100-8, 2015 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-25584858

RESUMO

Nanoporous structures of a p-type semiconductor, delafossite CuAlO(2), with a high crystallinity have been fabricated through an inorganic/polymer double-gel process and characterized for the first time via Mott-Schottky measurements. The effect of the precursor concentration, calcination temperature, and atmosphere were examined to achieve high crystallinity and photoelectrochemical properties while maximizing the porosity. The optical properties of the nanoporous CuAlO(2) are in good agreement with the literature with an optical band gap of 3.9 eV, and the observed high electrical conductivity and hole concentrations conform to highly crystalline and well-sintered nanoparticles observed in the product. The Mott-Schottky plot from the electrochemical impedance spectroscopy studies indicates a flat-band potential of 0.49 V versus Ag/AgCl. It is concluded that CuAlO(2) exhibits band energies very close to those of NiO but with electrical properties very desirable in the fabrication of photoelectrochemical devices including dye-sensitized solar cells.


Assuntos
Óxidos/química , Cristalização , Espectroscopia Dielétrica , Condutividade Elétrica , Eletrodos , Géis , Microscopia Eletrônica de Transmissão , Nanoporos/ultraestrutura , Semicondutores , Espectrofotometria Ultravioleta , Propriedades de Superfície
5.
Heliyon ; 10(1): e23985, 2024 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-38268575

RESUMO

The perovskite solar cells, founded on lead halides, have garnered significant attention from the photovoltaic industry owing to their superior efficiency, ease of production, lightweight characteristics, and affordability. However, due to the hazardous nature of lead-based compounds, these solar cells are currently unsuitable for commercial production. In this context, a lead-free perovskite, cesium-bismuth iodide (Cs3Bi2I9) is considered as a potential alternative to the lead halide-based cell due to their non-toxicity and stability, but this perovskite cannot be matched with random hole transport layer (HTL) and electron transport layer (ETL) materials compared to lead halide-based perovskite because of their crystal structure and band gap. Therefore, in this study, performance comparison of different ideal HTL and ETL materials for Cs3Bi2I9 perovskite layer were studied using SCAPS-1D device simulation on the basis of open circuit voltage, short circuit current, power conversion efficiency (PCE) and fill factor (FF) as well as several novel PSC configuration models were designed that can direct for further experimental research for PSC device commercialization. Results from this investigation reveals that the maximum efficiency of 20.96 % is obtained for the configuration ITO/WS2/Cs3Bi2I9/NiO/Au with optimized parameters such as thickness 400 nm, band gap 2.1eV, absorber layer defect density 1012 cm-3, donor density of ETL 1018 cm-3 and the acceptor density of HTL 1020 cm-3.

6.
Sci Rep ; 14(1): 13590, 2024 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-38866866

RESUMO

Cameroon is currently grappling with a significant energy crisis, which is adversely affecting its economy due to cost, reliability, and availability constraints within the power infrastructure. While electrochemical storage presents a potential remedy, its implementation faces hurdles like high costs and technical limitations. Conversely, generator-based systems, although a viable alternative, bring their own set of issues such as noise pollution and demanding maintenance requirements. This paper meticulously assesses a novel hybrid energy system specifically engineered to meet the diverse energy needs of Douala, Cameroon. By employing advanced simulation techniques, especially the Hybrid Optimization Model for Electric Renewable (HOMER) Pro program, the study carefully examines the intricacies of load demands across distinct consumer categories while accommodating varied pricing models. The paper offers a detailed analysis of the proposed grid-connected PV/Diesel/Generator system, aiming to gauge its performance, economic feasibility, and reliability in ensuring uninterrupted energy supply. Notably, the study unveils significant potential for cost reduction per kilowatt-hour, indicating promising updated rates of $0.07/kW, $0.08/kW, and $0.06/kW for low, medium, and high usage groups, respectively. Furthermore, the research underscores the importance of overcoming operational challenges and constraints such as temperature fluctuations, equipment costs, and regulatory compliance. It also acknowledges the impact of operational nuances like maintenance and grid integration on system efficiency. As the world progresses towards renewable energy adoption and hybrid systems, this investigation lays a strong foundation for future advancements in renewable energy integration and energy management strategies. It strives to create a sustainable energy ecosystem in Cameroon and beyond, where hybrid energy systems play a pivotal role in mitigating power deficiencies and supporting sustainable development.

7.
J Gastroenterol Hepatol ; 28(8): 1403-9, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23488792

RESUMO

BACKGROUND AND AIM: The purpose of this study is to assess whether the decrease in CD8 cells has any role in the development of non-alcoholic fatty liver disease (NAFLD). In this study, we therefore used antigen peptide transporter 1 (TAP1(-/-)) mice that cannot transport major histocompatibility complex class I antigens onto the cell surface resulting in failure of the generation of CD8 cells. METHODS: Wild-type C57Bl/6J and TAP1(-/-) mice were fed with 30% fructose solution for 8 weeks. The percentage of CD4, CD8 cells in peripheral blood mononuclear cells, and liver were sorted by fluorescence-activated cell sorting in both control and fructose-treated mice. Bodyweight, histopathological changes, oil red O staining, glucose tolerance test, intraperitoneal insulin tolerance test, serum levels of triglycerides, cholesterol, aspartate aminotransferase, and alanine aminotransferase were also evaluated. Quantitative real-time polymerase chain reaction was performed to determine the expression of specific genes involved in development of fatty changes in the liver. RESULTS: Chronic consumption of fructose in TAP1(-/-) mice did not develop NAFLD, insulin resistance, or change in level of CD8 cells. Moreover, there was delay in relative expression levels of genes involved in development of NAFLD in fructose-treated TAP1(-/-) mice. CONCLUSION: Taken together, the data suggest that TAP1(-/-) -deficient mice displayed reduced levels of CD8 cells that have a vital role in the initiation and propagation of liver inflammation and is a casual role in the beginning of fructose-induced liver damage as well as insulin resistance in mice.


Assuntos
Transportadores de Cassetes de Ligação de ATP/fisiologia , Linfócitos T CD8-Positivos/imunologia , Fígado Gorduroso/genética , Fígado Gorduroso/imunologia , Frutose , Membro 2 da Subfamília B de Transportadores de Cassetes de Ligação de ATP , Animais , Linfócitos T CD8-Positivos/metabolismo , Modelos Animais de Doenças , Fígado Gorduroso/induzido quimicamente , Antígenos de Histocompatibilidade Classe I/metabolismo , Ativação Linfocitária , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Soluções
8.
Heliyon ; 9(6): e16387, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37260898

RESUMO

Ion Transport Membrane (ITM) is an emerging technology for producing O2 by separating air in its membrane. To decrease energy loss in air separation unit and to increase the overall efficiency of a power generation unit ITM is added with the gasification unit in this model. Ceramic materials are generally used to make the ion transport membrane that produces oxygen by conducting oxygen ions at a specified temperature. Potential advantages can be gained by integrating ITM technology with power generation units as 99% pure oxygen is produced from ITM. Using ITM air separator is more beneficial compared to cryogenic air separation as ITM technology helps to improve IGCC overall efficiency and also reduces plant auxiliaries than that of power generation systems integrated with cryogenic. This paper proposed a novel and effective integration of ITM, gas turbine, HRSG system, gas clean up system and gasification unit to produce sustainable energy. Environmental impacts are considered to design this integrated power generation unit. The proposed model achieved a high gross electric efficiency of 47.58% and high net power of 296730 kW which revealed its potentiality compared to available cryogenic ASU-based combine cycle power plants.

9.
Nanomaterials (Basel) ; 13(6)2023 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-36985960

RESUMO

In recent years, the increasing energy requirement and consumption necessitates further improvement in energy storage technologies to obtain high cycling stability, power and energy density, and specific capacitance. Two-dimensional metal oxide nanosheets have gained much interest due to their attractive features, such as composition, tunable structure, and large surface area which make them potential materials for energy storage applications. This review focuses on the establishment of synthesis approaches of metal oxide nanosheets (MO nanosheets) and their advancements over time, as well as their applicability in several electrochemical energy storage systems, such as fuel cells, batteries, and supercapacitors. This review provides a comprehensive comparison of different synthesis approaches of MO nanosheets, as well their suitability in several energy storage applications. Among recent improvements in energy storage systems, micro-supercapacitors, and several hybrid storage systems are rapidly emerging. MO nanosheets can be employed as electrode and catalyst material to improve the performance parameters of energy storage devices. Finally, this review outlines and discusses the prospects, future challenges, and further direction for research and applications of metal oxide nanosheets.

10.
Proc Natl Acad Sci U S A ; 106(32): 13186-9, 2009 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-19651605

RESUMO

One of the applications of nanomaterials is as reinforcements in composites, wherein small additions of nanomaterials lead to large enhancements in mechanical properties. There have been extensive studies in the literature on composites where a polymer matrix is reinforced by a single nanomaterial such as carbon nanotubes. In this article, we examine the significant synergistic effects observed when 2 different types of nanocarbons are incorporated in a polymer matrix. Thus, binary combinations of nanodiamond, few-layer graphene, and single-walled nanotubes have been used to reinforce polyvinyl alcohol. The mechanical properties of the resulting composites, evaluated by the nanoindentation technique, show extraordinary synergy, improving the stiffness and hardness by as much as 400% compared to those obtained with single nanocarbon reinforcements. These results suggest a way of designing advanced materials with extraordinary mechanical properties by incorporating small amounts of 2 nanomaterials such as graphene plus nanodiamond or nanodiamond plus carbon nanotube.

11.
MRS Energy Sustain ; 9(1): 79-93, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36820104

RESUMO

Abstract: A great number of populations of the world, primarily in developing countries, are living in rural areas and are commonly isolated from the grid connection. Unstable power supply and increasing energy prices have significant effects on developing countries, especially during this COVID-19 pandemic. Renewable energy sources can provide sustainable and efficient electricity supply. Murzuq is a rural community situated in the southern part of Libya and endowed with renewable energy resources. While there is high electricity consumption during the lockdown, health clinics also experienced higher energy consumption of longer operating hours and an increased number of electrical appliances. This study investigates the techno-economic assessment of three different hybrid energy systems for health clinics in Murzuq. HOMER (Hybrid optimization model for electric renewables) software tool was used to evaluate the feasibility of employing renewable energy, to provide sustainable energy supply to the clinic. The current unsteady energy supply comes from the national grid and the current energy supply is not sufficient for the clinic's operating hours and requires a sustainable and steady supply. Measured data collected from the health clinic and HOMER software were used to analyze and optimize the change in overall electricity demand for the health clinic before and during the COVID-19 pandemic. The results showed that the photovoltaic/battery hybrid energy system has a lower net present cost, compared to the Photovoltaic/Generator set/ battery hybrid energy system, but higher than the standalone generator set. However, the highest amount of carbon emission associated with the standalone generator set compared to the other two hybrid energy systems disqualifies it from being a suitable contender for the source of electricity for the health clinic. The photovoltaic/battery was deemed to be most economically beneficial in terms of emission reduction and energy price. The outcomes of this investigation will help stakeholders and designers to optimize hybrid energy systems that economically meet the health clinic energy demands, especially during this pandemic.

12.
PLoS One ; 17(7): e0271045, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35802574

RESUMO

BACKGROUND: Foeniculum vulgare, F. vulgare, commonly known as fennel, is believed to be one of the world's oldest medicinal herbs and has been exploited by people for centuries as a nutritional aid for digestive disorders. In many southeast Asian countries, it is ingested as an after-meal snack, mukhvas, due to its breath-freshening and digestive aid properties. F. vulgare is used in some countries, such as Iran, as a complementary and alternative treatment for inflammatory bowel disease (IBD). METHODS: This study investigated the effects of fennel seed extract on intestinal epithelium barrier function and the Signal Transducer and Activator of Transcription (STAT) pathway. This pathway is active in inflammatory bowel disease. To study the protective effects of fennel seed extract in vitro, monolayers derived from the T84 colonic cell line were challenged with interferon-gamma (IFN-γ) and monitored with and without fennel seed extract. To complement our in vitro studies, the dextran sodium sulfate induced murine colitis model was employed to ascertain whether the protective effect of fennel seed extract can be recapitulated in vivo. RESULTS: Fennel seed extract was shown to exert a protective effect on transepithelial electrical resistance (TEER) in both T84 and murine models and showed increases in tight junction-associated mRNA in T84 cell monolayers. Both models demonstrated significant decreases in phosphorylated STAT1 (pSTAT1), indicating reduced activation of the STAT pathway. Additionally, mice treated with fennel seed showed significantly lower ulcer indices than control mice. CONCLUSIONS: We conclude barrier function of the gastrointestinal tract is improved by fennel seed extract, suggesting the potential utility of this agent as an alternative or adjunctive therapy in IBD.


Assuntos
Foeniculum , Doenças Inflamatórias Intestinais , Plantas Medicinais , Animais , Humanos , Doenças Inflamatórias Intestinais/tratamento farmacológico , Mucosa Intestinal , Camundongos , Extratos Vegetais/farmacologia , Sementes
13.
Chemphyschem ; 12(12): 2322-7, 2011 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-21744458

RESUMO

Gold nanoparticles with average diameters in the range 2.5-15 nm, prepared at the organic/aqueous interface by using tetrakis(hydroxymethyl)phosphonium chloride (THPC) as reducing agent, exhibit ferromagnetism whereby the saturation magnetization M(S) increases with decreasing diameter and varies linearly with the fraction of surface atoms. The value of M(S) is higher when the particles are present as a film instead of as a sol. Capping with strongly interacting ligands such as alkane thiols results in a higher M(S) value, which varies with the strength of the metal-sulfur bond. Ferromagnetism is also found in Pt and Ag nanoparticles prepared as sols, and the M(S) values vary as Pt>Au>Ag. A careful study of the temperature variation of the magnetization of Au nanoparticles, along with certain other observations, suggests that small bare nanoparticles of noble metals could indeed possess ferromagnetism, albeit weak, which is accentuated in the presence of capping agents, specially alkane thiols which form strong metal-sulfur bonds.


Assuntos
Ouro/química , Nanopartículas Metálicas/química , Nanotecnologia/métodos , Platina/química , Prata/química , Fenômenos Magnéticos , Imãs , Teste de Materiais , Compostos Organofosforados/química , Tamanho da Partícula , Compostos de Sulfidrila/química
14.
Chemphyschem ; 12(5): 937-43, 2011 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-21384487

RESUMO

The changes in the electronic and magnetic properties of graphene induced by interaction with semiconducting oxide nanoparticles such as ZnO and TiO(2) and with magnetic nanoparticles such as Fe(3)O(4), CoFe(2)O(4), and Ni are investigated by using Raman spectroscopy, magnetic measurements, and first-principles calculations. Significant electronic and magnetic interactions between the nanoparticles and graphene are found. The findings suggest that changes in magnetization as well as the Raman shifts are directly linked to charge transfer between the deposited nanoparticles and graphene. The study thus demonstrates significant effects in tailoring the electronic structure of graphene for applications in futuristic electronic devices.

15.
Cell Mol Gastroenterol Hepatol ; 12(4): 1353-1371, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34198013

RESUMO

BACKGROUND & AIMS: Congenital tufting enteropathy (CTE) is an intractable diarrheal disease of infancy caused by mutations of epithelial cell adhesion molecule (EpCAM). The cellular and molecular basis of CTE pathology has been elusive. We hypothesized that the loss of EpCAM in CTE results in altered lineage differentiation and defects in absorptive enterocytes thereby contributing to CTE pathogenesis. METHODS: Intestine and colon from mice expressing a CTE-associated mutant form of EpCAM (mutant mice) were evaluated for specific markers by quantitative real-time polymerase chain reaction, Western blotting, and immunostaining. Body weight, blood glucose, and intestinal enzyme activity were also investigated. Enteroids derived from mutant mice were used to assess whether the decreased census of major secretory cells could be rescued. RESULTS: Mutant mice exhibited alterations in brush-border ultrastructure, function, disaccharidase activity, and glucose absorption, potentially contributing to nutrient malabsorption and impaired weight gain. Altered cell differentiation in mutant mice led to decreased enteroendocrine cells and increased numbers of nonsecretory cells, though the hypertrophied absorptive enterocytes lacked key features, causing brush border malfunction. Further, treatment with the Notch signaling inhibitor, DAPT, increased the numbers of major secretory cell types in mutant enteroids (graphical abstract 1). CONCLUSIONS: Alterations in intestinal epithelial cell differentiation in mutant mice favor an increase in absorptive cells at the expense of major secretory cells. Although the proportion of absorptive enterocytes is increased, they lack key functional properties. We conclude that these effects underlie pathogenic features of CTE such as malabsorption and diarrhea, and ultimately the failure to thrive seen in patients.


Assuntos
Diarreia Infantil/etiologia , Diarreia Infantil/metabolismo , Suscetibilidade a Doenças , Mucosa Intestinal/metabolismo , Mucosa Intestinal/patologia , Síndromes de Malabsorção/etiologia , Síndromes de Malabsorção/metabolismo , Animais , Biomarcadores , Diferenciação Celular/genética , Diarreia Infantil/patologia , Modelos Animais de Doenças , Células Enteroendócrinas/metabolismo , Molécula de Adesão da Célula Epitelial/genética , Molécula de Adesão da Célula Epitelial/metabolismo , Regulação da Expressão Gênica , Predisposição Genética para Doença , Glucose/metabolismo , Humanos , Mucosa Intestinal/ultraestrutura , Síndromes de Malabsorção/patologia , Camundongos , Mutação , Permeabilidade , Transdução de Sinais
16.
Sci Technol Adv Mater ; 11(5): 054502, 2010 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27877359

RESUMO

Graphenes with varying number of layers can be synthesized by using different strategies. Thus, single-layer graphene is prepared by micromechanical cleavage, reduction of single-layer graphene oxide, chemical vapor deposition and other methods. Few-layer graphenes are synthesized by conversion of nanodiamond, arc discharge of graphite and other methods. In this article, we briefly overview the various synthetic methods and the surface, magnetic and electrical properties of the produced graphenes. Few-layer graphenes exhibit ferromagnetic features along with antiferromagnetic properties, independent of the method of preparation. Aside from the data on electrical conductivity of graphenes and graphene-polymer composites, we also present the field-effect transistor characteristics of graphenes. Only single-layer reduced graphene oxide exhibits ambipolar properties. The interaction of electron donor and acceptor molecules with few-layer graphene samples is examined in detail.

17.
J Clin Med ; 10(1)2020 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-33374714

RESUMO

Congenital tufting enteropathy (CTE) is an autosomal recessive disease of infancy that causes severe intestinal failure with electrolyte imbalances and impaired growth. CTE is typically diagnosed by its characteristic histological features, including villous atrophy, crypt hyperplasia and focal epithelial tufts consisting of densely packed enterocytes. Mutations in the EPCAM and SPINT2 genes have been identified as the etiology for this disease. The significant morbidity and mortality and lack of direct treatments for CTE patients demand a better understanding of disease pathophysiology. Here, the latest knowledge of CTE biology is systematically reviewed, including clinical aspects, disease genetics, and research model systems. Particular focus is paid to the pathogenesis of CTE and predicted mechanisms of the disease as these would provide insight for future therapeutic options. The contribution of intestinal homeostasis, including the role of intestinal cell differentiation, defective enterocytes, disrupted barrier and cell-cell junction, and cell-matrix adhesion, is vividly described here (see Graphical Abstract). Moreover, based on the known dynamics of EpCAM signaling, potential mechanistic pathways are highlighted that may contribute to the pathogenesis of CTE due to either loss of EpCAM function or EpCAM mutation. Although not fully elucidated, these pathways provide an improved understanding of this devastating disease.

18.
Cells ; 9(4)2020 04 11.
Artigo em Inglês | MEDLINE | ID: mdl-32290509

RESUMO

Congenital tufting enteropathy (CTE) is a rare chronic diarrheal disease of infancy caused by mutations in epithelial cell adhesion molecule (EpCAM). Previously, a murine CTE model showed mis-localization of EpCAM away from the basolateral cell surface in the intestine. Here we demonstrate that mutant EpCAM accumulated in the endoplasmic reticulum (ER) where it co-localized with ER chaperone, GRP78/BiP, revealing potential involvement of ER stress-induced unfolded protein response (UPR) pathway in CTE. To investigate the significance of ER-localized mutant EpCAM in CTE, activation of the three UPR signaling branches initiated by the ER transmembrane protein components IRE1, PERK, and ATF6 was tested. A significant reduction in BLOS1 and SCARA3 mRNA levels in EpCAM mutant intestinal cells demonstrated that regulated IRE1-dependent decay (RIDD) was activated. However, IRE1 dependent XBP1 mRNA splicing was not induced. Furthermore, an increase in nuclear-localized ATF6 in mutant intestinal tissues revealed activation of the ATF6-signaling arm. Finally, an increase in both the phosphorylated form of the translation initiation factor, eIF2α, and ATF4 expression in the mutant intestine provided support for activation of the PERK-mediated pathway. Our results are consistent with a significant role for UPR in gastrointestinal homeostasis and provide a working model for CTE pathophysiology.


Assuntos
Diarreia Infantil/genética , Molécula de Adesão da Célula Epitelial/genética , Síndromes de Malabsorção/genética , Resposta a Proteínas não Dobradas/genética , Animais , Doença Crônica , Modelos Animais de Doenças , Chaperona BiP do Retículo Endoplasmático , Humanos , Recém-Nascido , Camundongos
19.
Stem Cell Res Ther ; 11(1): 412, 2020 09 23.
Artigo em Inglês | MEDLINE | ID: mdl-32967734

RESUMO

BACKGROUND: Cell therapy is one of the most promising therapeutic interventions for retinitis pigmentosa. In the current study, we aimed to assess if peripheral blood-derived monocytes which are highly abundant and accessible could be utilized as a potential candidate for phenotypic differentiation into neuron-like cells. METHODS: The peripheral blood-derived monocytes were reconditioned phenotypically using extrinsic growth factors to induce pluripotency and proliferation. The reconditioned monocytes (RM) were further incubated with a cocktail of growth factors involved in retinal development and growth to induce retinal neuron-like properties. These cells, termed as retinal neuron-like cells (RNLCs) were characterized for their morphological, molecular and functional behaviour in vitro and in vivo. RESULTS: The monocytes de-differentiated in vitro and acquired pluripotency with the expression of prominent stem cell markers. Treatment of RM with retinal growth factors led to an upregulation of neuronal and retinal lineage markers and downregulation of myeloid markers. These cells show morphological alterations resembling retinal neuron-like cells and expressed photoreceptor (PR) markers. The induced RNLCs also exhibited relative membrane potential change upon light exposure suggesting that they have gained some neuronal characteristics. Further studies showed that RNLCs could also integrate in an immune-deficient retinitis pigmentosa mouse model NOD.SCID-rd1 upon sub-retinal transplantation. The RNLCs engrafted in the inner nuclear layer (INL) and ganglion cell layer (GCL) of the RP afflicted retina. Mice transplanted with RNLCs showed improvement in depth perception, exploratory behaviour and the optokinetic response. CONCLUSIONS: This proof-of-concept study demonstrates that reconditioned monocytes can be induced to acquire retinal neuron-like properties through differentiation using a defined growth media and can be a potential candidate for cell therapy-based interventions and disease modelling for ocular diseases.


Assuntos
Monócitos , Retina , Animais , Diferenciação Celular , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Neurônios
20.
Nanotechnology ; 20(12): 125705, 2009 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-19420482

RESUMO

The mechanical properties of polyvinyl alcohol (PVA) and poly(methyl methacrylate) (PMMA)-matrix composites reinforced by functionalized few-layer graphene (FG) have been evaluated using the nano-indentation technique. A significant increase in both the elastic modulus and hardness is observed with the addition of 0.6 wt% of graphene. The crystallinity of PVA also increases with the addition of FG. This and the good mechanical interaction between the polymer and the FG, which provides better load transfer between the matrix and the fiber, are suggested to be responsible for the observed improvement in mechanical properties of the polymers.

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