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1.
Nanotechnology ; 32(40)2021 Jul 14.
Artículo en Inglés | MEDLINE | ID: mdl-34192681

RESUMEN

Electrostatic nanogenerators or capacitive sensors that leverage electrostatic induction for power generation or sensing, has attracted significant interests due to their simple structure, ease of fabrication, and high device stability. However, in order for such devices to work, an additional power source or a post-charging process is necessary to activate the electrostatic effect. In this work, an electrostatic nanogenerator is fabricated using electrospun polystyrene (PS) mats and dip-coated graphene oxide (GO) films as the self-charged components. The electret performances of the PS mats and GO films are characterized via the electrostatic force microscopy phase shift and surface potential measurements. With a multilayer device structure that consists of top electrodes/GO films/spacer/electrospun PS mats/bottom electrodes, the resultant device acts as an electrostatic generator that operates in the noncontact mode. The nanogenerator can output a peak voltage of ca. 6.41 V and a peak current of ca. 6.57 nA at a rate of 1 Hz of mechanical compression, and with no attenuation of electrical outputs even after 50 000 cycles over a 13 h period. Furthermore, this as-prepared device is also capable of serving as a self-powered capacitive sensor for detection of tiny mechanical impacts and measurement of human finger bending. This results of this work provides a new avenue to easily fabricate electrostatic nanogenerators with high durability and self-powered capacitive sensors for the detection of small impacts.

2.
Phys Chem Chem Phys ; 23(1): 94-106, 2021 Jan 06.
Artículo en Inglés | MEDLINE | ID: mdl-33325463

RESUMEN

The fundamental factor affecting the stability of perovskite solar cells, ion migration, has been reviewed, which is found to be closely related to the degradation of perovskite solar cells. Characterization methods like impedance spectroscopy and galvanostatic measurement to identify ion migration in perovskite films have been reviewed. The influence of light on ion migration was further discussed, which could largely explain the photo-stability decay in most perovskite solar cells. Finally, several solutions to inhibit ion migration for better operational stability of perovskite solar cells were summarized, including bulk passivation, interface passivation and grain boundary passivation. Several strategies have also been proposed to further improve the stablity of perovskite solar cells.

3.
J Cell Mol Med ; 22(4): 2357-2367, 2018 04.
Artículo en Inglés | MEDLINE | ID: mdl-29431269

RESUMEN

This study purposed to explore the correlation between miR-129-5p and TGIF2 and their impacts on glioma cell progression. Differentially expressed miRNA was screened through microarray analysis. MiR-129-5p expression levels in glioma tissues and cells were measured by qRT-PCR. CCK-8 assay, flow cytometer, transwell assay and wound-healing assay were employed to detect cell proliferation, apoptosis and cycle, invasiveness and migration, respectively. Dual-luciferase reporting assay was performed to confirm the targeted relationship between miR-129-5p and TGIF2. The effects of TGIF2 expression on cell biological functions were also investigated using the indicated methods. Tumour xenograft was applied to explore the impact of miR-129-5p on tumorigenesis in vivo. MiR-129-5p expression was down-regulated in both glioma tissues and glioma cells, while TGIF2 expression was aberrantly higher than normal level. Dual-luciferase reporter assay validated the targeting relation between miR-129-5p and TGIF2. Overexpression of miR-129-5p or down-regulation of TGIF2 inhibited the proliferation, invasion and migration capacity of glioma cells U87 and U251, and meanwhile blocked the cell cycle as well as induced cell apoptosis. MiR-129-5p overexpression repressed the tumour development in vivo. MiR-129-5p and TGIF2 had opposite biological functions in glioma cells. MiR-129-5p could inhibit glioma cell progression by targeting TGIF2, shining light for the development of target treatment for glioma.


Asunto(s)
Carcinogénesis/genética , Glioma/genética , Proteínas de Homeodominio/genética , MicroARNs/genética , Proteínas Represoras/genética , Animales , Apoptosis/genética , Movimiento Celular/genética , Proliferación Celular/genética , Progresión de la Enfermedad , Femenino , Regulación Neoplásica de la Expresión Génica , Glioma/patología , Humanos , Masculino , Ratones , Invasividad Neoplásica/genética , Invasividad Neoplásica/patología , Ensayos Antitumor por Modelo de Xenoinjerto
4.
PLoS Genet ; 11(5): e1005264, 2015 May.
Artículo en Inglés | MEDLINE | ID: mdl-26000445

RESUMEN

Intragenic microRNAs (miRNAs), located mostly in the introns of protein-coding genes, are often co-expressed with their host mRNAs. However, their functional interaction in development is largely unknown. Here we show that in Drosophila, miR-92a and miR-92b are embedded in the intron and 3'UTR of jigr1, respectively, and co-expressed with some jigr1 isoforms. miR-92a and miR-92b are highly expressed in neuroblasts of larval brain where Jigr1 expression is low. Genetic deletion of both miR-92a and miR-92b demonstrates an essential cell-autonomous role for these miRNAs in maintaining neuroblast self-renewal through inhibiting premature differentiation. We also show that miR-92a and miR-92b directly target jigr1 in vivo and that some phenotypes due to the absence of these miRNAs are partially rescued by reducing the level of jigr1. These results reveal a novel function of the miR-92 family in Drosophila neuroblasts and provide another example that local negative feedback regulation of host genes by intragenic miRNAs is essential for animal development.


Asunto(s)
Proteínas de Unión al ADN/metabolismo , Regulación hacia Abajo , Proteínas de Drosophila/metabolismo , Drosophila/genética , MicroARNs/metabolismo , Células-Madre Neurales/citología , Regiones no Traducidas 3' , Animales , Encéfalo/embriología , Encéfalo/metabolismo , Proteínas de Unión al ADN/genética , Proteínas de Drosophila/genética , Regulación del Desarrollo de la Expresión Génica , Larva/genética , Larva/metabolismo , Masculino , MicroARNs/genética , Células-Madre Neurales/metabolismo , Neuroglía/citología , Neuroglía/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo , Alineación de Secuencia
5.
Angew Chem Int Ed Engl ; 57(34): 10959-10965, 2018 Aug 20.
Artículo en Inglés | MEDLINE | ID: mdl-29953706

RESUMEN

A readily available small molecular hole-transporting material (HTM), OMe-TATPyr, was synthesized and tested in perovskite solar cells (PSCs). OMe-TATPyr is a two-dimensional π-conjugated molecule with a pyrene core and four phenyl-thiophene bridged triarylamine groups. It can be readily synthesized in gram scale with a low lab cost of around US$ 50 g-1 . The incorporation of the phenyl-thiophene units in OMe-TATPyr are beneficial for not only carrier transportation through improved charge delocalization and intermolecular stacking, but also potential trap passivation via Pb-S interaction as supported by depth-profiling XPS, photoluminescence, and electrochemical impedance analysis. As a result, an impressive best power conversion efficiency (PCE) of up to 20.6 % and an average PCE of 20.0 % with good stability has been achieved for mixed-cation PSCs with OMe-TATPyr with an area of 0.09 cm2 . A device with an area of 1.08 cm2 based on OMe-TATPyr demonstrates a PCE of 17.3 %.

6.
Development ; 139(16): 2891-6, 2012 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-22791898

RESUMEN

Patj has been characterized as one of the so-called polarity proteins that play essential and conserved roles in regulating cell polarity in many different cell types. Studies of Drosophila and mammalian cells suggest that Patj is required for the apical polarity protein complex Crumbs-Stardust (Pals1 or Mpp5 in mammalian cells) to establish apical-basal polarity. However, owing to the lack of suitable genetic mutants, the exact in vivo function of Patj in regulating apical-basal polarity and development remains to be elucidated. Here, we generated molecularly defined null mutants of Drosophila Patj (dPatj). Our data show conclusively that dPatj only plays supporting and non-essential roles in regulating apical-basal polarity, although such a supporting role may become crucial in cells such as photoreceptors that undergo complex cellular morphogenesis. In addition, our results confirm that dPatj possesses an as yet unidentified function that is essential for pupal development.


Asunto(s)
Polaridad Celular/fisiología , Supervivencia Celular/fisiología , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/citología , Drosophila melanogaster/metabolismo , Proteínas del Ojo/metabolismo , Proteínas de la Membrana/metabolismo , Animales , Animales Modificados Genéticamente , Secuencia de Bases , Polaridad Celular/genética , Supervivencia Celular/genética , Cartilla de ADN/genética , Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Drosophila melanogaster/crecimiento & desarrollo , Proteínas del Ojo/genética , Regulación del Desarrollo de la Expresión Génica , Genes de Insecto , Proteínas de la Membrana/genética , Mutación , Fenotipo , Pupa/crecimiento & desarrollo , Pupa/metabolismo
7.
Zhonghua Yi Xue Za Zhi ; 95(43): 3533-6, 2015 Nov 17.
Artículo en Zh | MEDLINE | ID: mdl-26813279

RESUMEN

OBJECTIVE: To study the mRNA expression level of growth inhibition factor 4 (ING4) and hypoxia inducing factor 1 alpha (HIF-1 alpha), and their relationship with tumor malignant degree or the pathology classification in human brain astrocytoma. METHODS: The mRNA expression levels of ING4 and HIF-1 alpha were detected by RT-PCR method in 45 cases of grade I-IV human brain astrocytoma and 11 cases of control brain tissues from January 2009 to June 2010 in the Second Affiliated Hospital of Zhengzhou University, and their correlation was also analyzed. RESULTS: In the non-tumor brain tissue, the expression level of ING4 mRNA was 1.19 ± 0.22, while they were 0.91 ± 0.19, 0.74 ± 0.28, 0.54 ± 0.33 and 0.22 ± 0.19 in I-IV grade astrocytoma, respectively. Compared with the non-tumor control, the mRNA expression level of ING4 gene decreased significantly in the astrocytoma (P<0.05). And the expression of ING4 gradually reduced with the increase of the pathological classification of the astrocytoma.In the non-tumor brain tissue, the expression level of HIF-1 alpha mRNA was 0.26 ± 0.16, and they were 0.34 ± 0.19, 0.50 ± 0.23, 0.96 ± 0.15 and 1.04 ± 0.15 in I-IV grade astrocytoma, respectively.For HIF-1 alpha gene, the mRNA expression level increased significantly in the astrocytoma. Meanwhile, the expression gradually increased with the increase of the pathological classification of the astrocytoma (P<0.05). The mRNA expression showed a negative correlation between ING4 and HIF-1 alpha with the increase of the tumor malignant degree. CONCLUSION: The ING4 and HIF-1 alpha genes play a role in the tumorigenesis and development of human brain astrocytoma, and closely associate with the malignant degree of astrocytoma.


Asunto(s)
Astrocitoma , Neoplasias Encefálicas , Proteínas de Ciclo Celular , Proteínas de Homeodominio , Humanos , Subunidad alfa del Factor 1 Inducible por Hipoxia , ARN Mensajero , Proteínas Supresoras de Tumor
8.
BMC Complement Altern Med ; 14: 86, 2014 Mar 05.
Artículo en Inglés | MEDLINE | ID: mdl-24597831

RESUMEN

BACKGROUND: Radix Trichosanthis (RT), the dry root tuber of Trichosanthis kirilowii Maxim (Cucurbitaceae), is a traditional Chinese medicine. Although a wide range of saponin pharmacological properties has been identified, to our knowledge, this may be the first report to investigate the crude saponins from RT. The purpose of this study was to delineate the antioxidant activity both in vitro and in vivo by using ethyl acetate (EtOAc), n-butanol, and the mixture of n-butanol and EtOAc fractions. METHODS: In vitro antioxidant activity was detected by using DPPH free radical, hydrogen peroxide scavenging, and reducing power assays. After pretreatment with different fractions saponins at 2 mg/kg/d and 3 mg/kg/d of crude drug, respectively, an established CCl4 induced acute cytotoxicity model was used to evaluate the in vivo antioxidant potential by detection of superoxide dismutase (SOD), malonaldehyde (MDA), lactate dehydrogenase (LDH), and total antioxidant capacity (T-AOC) levels. RESULTS: The in vitro assay showed that the antioxidant activity of all the three fractions was promising. The reducing power of the EtOAc and the mixture of n-butanol and EtOAc extracts increased in a dose dependent manner. However, both the n-butanol and the mixture of n-butanol and EtOAc fractions in low dose exhibited in a time dependent manner with prolonged reaction time. As for hydrogen peroxide scavenging capability, the n-butanol fraction mainly demonstrated a time dependent manner, whereas EtOAc fraction showed a dose dependent manner. However, in case of in vivo assay, an increase of SOD and T-AOC and decrease of MDA and LDH levels were only observed in n-butanol (2 mg/kg/d of crude drug) extracts pretreatment group. CONCLUSIONS: RT saponins in n-butanol fraction might be a potential antioxidant candidate, as CCl4-induced oxidative stress has been found to be alleviated, which may be associated with the time dependent manner of n-butanol saponins in a low dose. Further studies will be needed to investigate the active individual components in n-butanol extract, in vivo antioxidant activities and antioxidant mechanisms.


Asunto(s)
Antioxidantes/farmacología , Medicamentos Herbarios Chinos/química , Extractos Vegetales/química , Saponinas/farmacología , Animales , Antioxidantes/toxicidad , Tetracloruro de Carbono/toxicidad , Enfermedad Hepática Inducida por Sustancias y Drogas/etiología , L-Lactato Deshidrogenasa/metabolismo , Masculino , Ratones , Estrés Oxidativo/efectos de los fármacos , Saponinas/toxicidad
9.
Zhonghua Yi Xue Za Zhi ; 94(23): 1820-4, 2014 Jun 17.
Artículo en Zh | MEDLINE | ID: mdl-25154851

RESUMEN

OBJECTIVE: To observe the effects of electrical hippocampal stimulation of α5 subunit of extrasynaptic GABA(A) receptor in kainic acid-induced epileptic rats, explore the optimal therapeutic parameters and elucidate the possible mechanism of electrical stimulation for hippocampal epilepsy. METHODS: A total of 40 healthy male Sprague Dawley (SD) rats were randomly divided into 5 groups of epilepsy, sham operation, low-frequency stimulation (LFS), high-frequency stimulation (HFS) and normal control (n = 8 each). The expression of α5 subunit of extrasynaptic GABA(A) receptor as well as the association with the curative effects of LFS were evaluated by behavioristics, real-time fluorogenic quantitative polymerase chain reaction (PCR) and Western blot. RESULTS: The kainic acid kindling rats had class V attack with a modeling success rate of 67%. After treatment, as compared with sham operation and epilepsy groups, the number of seizures decreased significantly in LFS and HFS treatment groups (P < 0.01). But LFS and HFS treatment groups were compared, the number of seizures has no statistical significance (P > 0.05). When sham operation and epilepsy groups were compared, the number of seizures was not statistically significant (P > 0.05). The paired inter-group comparisons showed that LFS and HFS treatment groups and sham operation and epilepsy groups had significant differences in α5 subunit mRNA and protein (P < 0.01). No statistical significance existed between LFS and HFS treatment groups (P > 0.05) or sham operation and HFS treatment groups (P > 0.05). As compared with normal control group, LFS treatment and HFS groups had significant difference (P < 0.01). CONCLUSION: Electrical hippocampal stimulation can effectively inhibit seizures. Both LFS and HFS are equally effective, but the former offers greater benefits. And an inhibition of extrasynaptic α5 subunit plays an important role in seizure during hippocampal stimulation.


Asunto(s)
Epilepsia/metabolismo , Hipocampo/metabolismo , Ácido Kaínico/toxicidad , Receptores de GABA-A/metabolismo , Convulsiones/metabolismo , Animales , Estimulación Eléctrica , Epilepsia/inducido químicamente , Hipocampo/efectos de los fármacos , Excitación Neurológica , Masculino , Ratas , Ratas Sprague-Dawley , Convulsiones/inducido químicamente
10.
Micromachines (Basel) ; 14(8)2023 Aug 16.
Artículo en Inglés | MEDLINE | ID: mdl-37630147

RESUMEN

To cope with the explosive increase in electromagnetic radiation intensity caused by the widespread use of electronic information equipment, high-performance electromagnetic wave (EMW)-absorbing materials that can adapt to various frequency bands of EMW are also facing great demand. In this paper, CH3NH3PbI3/graphene (MG) high-performance EMW-absorbing materials were innovatively synthesized by taking organic-inorganic hybrid perovskite (OIHP) with high equilibrium holes, electron mobility, and accessible synthesis as the main body, graphene as the intergranular component, and adjusting the component ratio. When the component ratio was 16:1, the thickness of the absorber was 1.87 mm, and MG's effective EMW absorption width reached 6.04 GHz (11.96-18.00 GHz), achieving complete coverage of the Ku frequency band. As the main body of the composite, CH3NH3PbI3 played the role of the polarization density center, and the defects and vacancies in the crystal significantly increased the polarization loss intensity; graphene, as a typical two-dimensional material distributed in the crystal gap, built an efficient electron transfer channel, which significantly improved the electrical conductivity loss strength. This work effectively broadened the EMW absorption frequency band of OIHP and promoted the research process of new EMW-absorbing materials based on OIPH.

11.
J Int Med Res ; 51(9): 3000605231194518, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-37684015

RESUMEN

OBJECTIVE: To analyze the clinical and genetic characteristics of zinc finger protein 408 (ZNF408)-related familial exudative vitreoretinopathy (FEVR) in a Chinese cohort. METHODS: Ninety families from Chongqing and 16 families from Xinjiang were selected according to fundus lesion characteristics. Peripheral venous blood was collected from patients and their families; genomic DNA was extracted for whole exome sequencing. Relationships between genotype and phenotype in patients with ZNF408-related FEVR were analyzed. RESULTS: ZNF408 variants were detected in three patients (2.83%, 3/106). ZNF408 variants in these three probands were all missense mutations at novel sites. One proband had a ZNF408 and LRP5 double-gene variant, and two probands had ZNF408 single-gene variants. Patients with double-gene variants did not display more severe clinical manifestations. CONCLUSIONS: This study expands the spectrum of known ZNF408 variants and confirms that ZNF408 variants can cause FEVR. Most variants detected in this study have not been reported in the literature and are suspected pathogenic variants of FEVR. In patients with FEVR, phenotype and genotype do not necessarily display a direct one-to-one relationship.


Asunto(s)
Proteínas de Unión al ADN , Vitreorretinopatías Exudativas Familiares , Mutación Missense , Factores de Transcripción , Humanos , Proteínas de Unión al ADN/genética , Vitreorretinopatías Exudativas Familiares/genética , Genotipo , Fenotipo , Factores de Transcripción/genética , Pueblos del Este de Asia
12.
Proc Natl Acad Sci U S A ; 106(20): 8284-9, 2009 May 19.
Artículo en Inglés | MEDLINE | ID: mdl-19429710

RESUMEN

With the completion of genome sequences of major model organisms, increasingly sophisticated genetic tools are necessary for investigating the complex and coordinated functions of genes. Here we describe a genetic manipulation system termed "genomic engineering" in Drosophila. Genomic engineering is a 2-step process that combines the ends-out (replacement) gene targeting with phage integrase phiC31-mediated DNA integration. First, through an improved and modified gene targeting method, a founder knock-out line is generated by deleting the target gene and replacing it with an integration site of phiC31. Second, DNA integration by phiC31 is used to reintroduce modified target-gene DNA into the native locus in the founder knock-out line. Genomic engineering permits directed and highly efficient modifications of a chosen genomic locus into virtually any desired mutant allele. We have successfully applied the genomic engineering scheme on 6 different genes and have generated at their loci more than 70 unique alleles.


Asunto(s)
Drosophila/genética , Ingeniería Genética/métodos , Genoma de los Insectos/genética , Alelos , Animales , Bacteriófagos/genética , Secuencia de Bases , Marcación de Gen , Integrasas , Datos de Secuencia Molecular , Mutación , Integración Viral
13.
Nanomaterials (Basel) ; 12(7)2022 Mar 26.
Artículo en Inglés | MEDLINE | ID: mdl-35407208

RESUMEN

With the increasing influence of electromagnetic radiation on precision instruments and organisms, there is an urgent need for research on lightweight and high-strength electromagnetic wave absorbing materials. This study has probed into a new composite absorbing material based on reduced graphene oxide (rGO)-NiMnO3, where the like-core-shell NiMnO3 is anchored on the rGO nanosheets to significantly improve the electromagnetic wave dissipation ability of the composite material using the inter-component dipole polarization and interface polarization. At the same time, NiMnO3 can effectively adjust the impedance matching ratio of rGO so that electromagnetic waves can effectively enter the absorbing material. At a thickness of 3.73 mm, the maximum absorption strength of rGO-NiMnO3 reaches -61.4 dB at 6.6 GHz; at a thickness of 2.5 mm, the adequate absorption bandwidth is 10.04-18.00 GHz, achieving a full coverage for the Ku band. As a new option for preparing lightweight and broadband electromagnetic wave absorbing materials, rGO-NiMnO3 is an ideal material for electromagnetic wave protection.

14.
Genetics ; 180(1): 703-7, 2008 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-18757917

RESUMEN

In this report, we describe several approaches to improve the scalability and throughput of major genetic crosses in ends-out gene targeting. We generated new sets of targeting vectors and fly stocks and introduced a novel negative selection marker that drastically reduced the frequency of false-positive targeting candidates.


Asunto(s)
Drosophila/genética , Técnicas Genéticas , Animales , Animales Modificados Genéticamente , Cromosomas/ultraestructura , Clonación Molecular , Cruzamientos Genéticos , Femenino , Marcación de Gen , Vectores Genéticos , Masculino , Ratones , Modelos Genéticos , Reacción en Cadena de la Polimerasa , Recombinación Genética
15.
J Mol Neurosci ; 66(2): 163-171, 2018 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-30242669

RESUMEN

p38 mitogen-activated protein kinase (MAPK) is a major player in mitochondrial dysfunction after subarachnoid hemorrhage (SAH). Moreover, DJ-1, which responds to oxidative stress and translocates to mitochondria, maintains mitochondrial homeostasis. Although a few studies have demonstrated that DJ-1 indirectly regulates p38 activation, the relationship between DJ-1 and p38 in mitochondrial dysfunction after SAH has not been delineated. Using an in vitro SAH model, alterations in p38, p-p38, DJ-1, and autophagic-related protein expression were detected. As expected, p38 inhibitor significantly blocked excessive expression of p38 and p-p38 after SAH, whereas total DJ-1 expression and mitochondrial DJ-1 were up-regulated. Further analysis showed that p38 inhibitor significantly blocked oxyhemoglobin (OxyHb) induced mitochondrial dysfunction, including mitochondrial membrane potential depolarization and reactive oxygen species (ROS) release. In addition, p38 inhibitor restored OxyHb-induced abnormal autophagic flux at the initiation and formation stage by regulating Atg5, beclin-1, the ratio of LC3-II/LC3-I, and p62 expression. This study suggested that overexpression of p38 induced the accumulation of mitochondrial dysfunction partly due to abnormal activation of autophagy, which largely relied on DJ-1 mitochondrial translocation.


Asunto(s)
Imidazoles/farmacología , Mitocondrias/metabolismo , Proteína Desglicasa DJ-1/metabolismo , Inhibidores de Proteínas Quinasas/farmacología , Piridinas/farmacología , Hemorragia Subaracnoidea/metabolismo , Proteínas Quinasas p38 Activadas por Mitógenos/antagonistas & inhibidores , Animales , Autofagia , Potencial de la Membrana Mitocondrial , Mitocondrias/efectos de los fármacos , Oxihemoglobinas/metabolismo , Células PC12 , Ratas , Especies Reactivas de Oxígeno/metabolismo , Proteínas Quinasas p38 Activadas por Mitógenos/metabolismo
16.
ACS Appl Mater Interfaces ; 10(39): 33205-33213, 2018 Oct 03.
Artículo en Inglés | MEDLINE | ID: mdl-30179000

RESUMEN

A consensus has been reached that organic transport layer (e.g., Spiro-OMeTAD) in perovskite solar cell (PSC) is prone to be impact by mobile ions in perovskite film during long-term operation. Here, we incorporate cesium acetate as a buffer layer into perovskite solar cells to mitigate this detrimental behavior, in which cesium acetate is sandwiched between perovskite and organic transport layer. The mobile ions that migrate toward the organic transport layer (e.g., MA+) are gradually consumed by cesium acetate, resulting in cesium-rich perovskite at the interface. This in situ reaction and the subsequent Cs incorporation greatly enhance the operational stability of PSC without efficiency loss. The optimized PSC presents a power conversion efficiency of 20.9% with an open-circuit voltage of 1.18 V, maintaining ∼80% of its initial efficiency after 4500 min continuous operation at maximum power point. This new strategy opens up a new opportunity for fabricating stable perovskite solar cells.

17.
Food Funct ; 9(12): 6349-6359, 2018 Dec 13.
Artículo en Inglés | MEDLINE | ID: mdl-30452052

RESUMEN

(-)-Epigallocatechin-3-gallate (EGCG), the main bioactive component of tea catechins, exhibits broad-spectrum health efficacy against mitochondrial damage after subarachnoid hemorrhage (SAH). The mechanisms, however, are largely unknown. Here, the ability of EGCG to rescue mitochondrial dysfunction and mitochondrial dynamics following the inhibition of cell death was investigated by using in vitro and in vivo SAH models. EGCG blocked the cytosolic channel ([Ca2+])i influx via voltage-gated calcium channels (VGCCs), which induced mitochondrial dysfunction, including mitochondrial membrane potential depolarization and reactive oxygen species (ROS) release. As expected, EGCG ameliorated oxyhemoglobin (OxyHb)-induced impairment of mitochondrial dynamics by regulating the expression of Drp1, Fis1, OPA1, Mfn1, and Mfn2. As a result, EGCG restored the increases in fragmented mitochondria and the mtDNA copy number in the OxyHb group to almost the normal level after SAH. In addition, the normal autophagic flux induced by EGCG at both the initiation and formation stages regulated Atg5 and Beclin-1 after SAH for the timely elimination of damaged mitochondria. In the end, EGCG increased the neurological score by decreasing cell death through the cyt c-mediated intrinsic apoptotic pathway. The results revealed the mechanisms behind the neuroprotective effects of EGCG via inhibition of the overloaded [Ca2+]i-induced mitochondrial dysfunction and the imbalanced mitochondrial fusion and fission cycle. Therefore, the simultaneous inhibition and timely elimination of damaged mitochondria could determine the therapeutic effect of EGCG.


Asunto(s)
Catequina/análogos & derivados , Dinámicas Mitocondriales/efectos de los fármacos , Fármacos Neuroprotectores/administración & dosificación , Hemorragia Subaracnoidea/tratamiento farmacológico , Animales , Apoptosis/efectos de los fármacos , Autofagia/efectos de los fármacos , Catequina/administración & dosificación , Citocromos c/metabolismo , Humanos , Masculino , Ratones , Mitocondrias/efectos de los fármacos , Mitocondrias/metabolismo , Estrés Oxidativo/efectos de los fármacos , Especies Reactivas de Oxígeno/metabolismo , Hemorragia Subaracnoidea/metabolismo , Hemorragia Subaracnoidea/fisiopatología
18.
J Phys Chem Lett ; 9(22): 6536-6543, 2018 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-30358406

RESUMEN

The organic-inorganic halide perovskites (OIHPs) have shown enormous potential for solar cells, while problems like the current-voltage hysteresis and the long-term instability have seriously hindered their applications. Ion migrations are believed to be relevant. But the atomistic details still remain unclear. Here we study the migrations of ions in CH3NH3PbI3 (MAPbI3) at varying temperatures ( T's), using combined experimental and first-principle theoretical methods. Classical hopping of the iodide ions is the main migration mechanism at moderate T's. Below ∼270 K, the kinetic constant for ionic migration still shows an Arrenhius dependency, but the much lower activation energy is attributed to the migration of H+. A gradual classical-to-quantum transition takes place between ∼140 and ∼80 K. Below ∼80 K, the kinetic constant becomes T-independent, suggesting that deep quantum tunneling of H+ takes over. This study gives direct experimental evidence for the migrations of H+s in MAPbI3 and confirms their quantum nature.

19.
Adv Mater ; : e1803095, 2018 Aug 23.
Artículo en Inglés | MEDLINE | ID: mdl-30141199

RESUMEN

The fabrication of high-quality perovskite film highly relies on chemical composition and the synthesis method of perovskite. So far, sequentially deposited MA0.03 FA0.97 Pb(I0.97 Br0.03 )3 polycrystalline film is adopted to produce high-performance perovskite solar cells with record power conversion efficiency (PCE). Fewer grain boundaries and incorporation of inorganic cation (e.g., cesium) would further increase device performance via sequential deposition. Here, cesium chloride (CsCl) is introduced into lead iodide (PbI2 ) precursor solution that beneficially modulates the property of PbI2 film, leading to larger grains with cesium incorporation in the resulting perovskite film. The enlarged crystal grains originate from a slower nucleation process for CsCl-containing PbI2 film when reacting with formamidine iodide, confirmed by in situ confocal photoluminescence imaging. Photovoltaic devices based on CsCl-containing PbI2 film demonstrate a higher averaging efficiency of 21.3% than 20.3% of the devices without CsCl additives for reverse scan. More importantly, the device stability is improved by CsCl additives that retain over 90% of their initial PCE value after 4000 min tracking at maximum power point under 1-sun illumination. This work paves a way to further improve the photovoltaic performance of mixed-cation-halide perovskite solar cells via a sequential deposition method.

20.
Mol Neurobiol ; 54(1): 392-405, 2017 01.
Artículo en Inglés | MEDLINE | ID: mdl-26742518

RESUMEN

Mitochondrial dysfunction and subsequent autophagy, which are common features in central nervous system (CNS) disorders, were found to contribute to neuronal cell injury after subarachnoid hemorrhage (SAH). (-)-Epigallocatechin-3-gallate (EGCG), the main biological active of tea catechin, is well known for its beneficial effects in the treatment of CNS diseases. Here, the ability of EGCG to rescue cellular injury and mitochondrial function following the improvement of autophagic flux after SAH was investigated. As expected, EGCG-protected mitochondrial function depended on the inhibition of cytosolic Ca2+ concentration ([Ca2+]i) influx via voltage-gated calcium channels (VGCCs) and, consequently, mitochondrial Ca2+ concentration ([Ca2+]m) overload via mitochondrial Ca2+ uniporter (MCU). The attenuated [Ca2+]i and [Ca2+]m levels observed in the EGCG-treated group likely lessened oxyhemoglobin (OxyHb)-induced mitochondrial dysfunction, including mitochondrial membrane potential depolarization, mitochondrial membrane permeability transition pore (mPTP) opening, reactive oxygen species (ROS), and cytochrosome c (cyt c) releasing. Subsequently, EGCG can restore the disrupted autophagy flux after SAH both at the initiation and formation stages by regulating Atg5, LC3B, and Becn-1 (Beclin-1) mRNA expressions. Thus, precondition EGCG resulted in autophagosomes and more autolysosomes compared with SAH group. As a result, EGCG pre-treatment increased the neurological score and decreased cell death. This study suggested that the mitochondrial dysfunction and abnormal autophagy flux synergistically contribute to SAH pathogenesis. Thus, EGCG can be regarded as a new pharmacological agent that targets both mitochondria and altered autophagy in SAH therapy.


Asunto(s)
Autofagia/fisiología , Catequina/análogos & derivados , Mitocondrias/patología , Fármacos Neuroprotectores/uso terapéutico , Hemorragia Subaracnoidea/patología , Hemorragia Subaracnoidea/prevención & control , Animales , Autofagia/efectos de los fármacos , Catequina/farmacología , Catequina/uso terapéutico , Supervivencia Celular/efectos de los fármacos , Supervivencia Celular/fisiología , Relación Dosis-Respuesta a Droga , Masculino , Ratones , Mitocondrias/efectos de los fármacos , Mitocondrias/metabolismo , Fármacos Neuroprotectores/farmacología , Células PC12 , Ratas , Hemorragia Subaracnoidea/metabolismo
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