排序方式: 共有143条查询结果,搜索用时 15 毫秒
81.
Fei Guo Xiangdong Zhu Karen Forberich Johannes Krantz Tobias Stubhan Michael Salinas Marcus Halik Stefanie Spallek Benjamin Butz Erdmann Spiecker Tayebeh Ameri Ning Li Peter Kubis Dirk M. Guldi Gebhard J. Matt Christoph J. Brabec 《Liver Transplantation》2013,3(8):1062-1067
Organic photovoltaic (OPV) solar cells that can be simply processed from solution are in the focus of the academic and industrial community because of their enormous potential to reduce cost. One big challenge in developing a fully solution‐processed OPV technology is the design of a well‐performing electrode system, allowing the replacement of ITO. Several solution‐processed electrode systems were already discussed, but none of them could match the performance of ITO. Here, we report efficient ITO‐free and fully solution‐processed semitransparent inverted organic solar cells based on silver nanowire (AgNW) electrodes. To demonstrate the potential of these AgNW electrodes, they were employed as both the bottom and top electrodes. Record devices achieved fill factors as high as 63.0%, which is comparable to ITO based reference devices. These results provide important progress for fully printed organic solar cells and indicate that ITO‐free, transparent as well as non‐transparent organic solar cells can indeed be fully solution‐processed without losses. 相似文献
82.
Markus Koppe Hans‐Joachim Egelhaaf Ewan Clodic Mauro Morana Larry Lüer Anna Troeger Vito Sgobba Dirk M. Guldi Tayebeh Ameri Christoph J. Brabec 《Liver Transplantation》2013,3(7):949-958
The photoresponse of P3HT:PC61BM based organic solar cells can be enhanced by blending the bulk heterojunction with the low band gap polymer Si‐ PCPDTBT. Organic solar cells containing the resulting ternary blend as the photoactive layer deliver short circuit currents of up to 15.5 mA cm?2. Morphological studies show modest phase separation without the perturbation of the crystallinity of the P3HT:PC61BM matrix, in accordance with the measured acceptable fill factors. Picosecond time‐resolved pump‐probe spectroscopy reveals that the sensitization of P3HT:PC61BM with Si‐PCPDTBT involves the transfer of photogenerated positive polarons from the low band gap polymer to P3HT within few hundreds of picoseconds. Intensity dependent experiments in combination with global fitting show that the charge transfer from Si‐PCPDTBT to P3HT competes with non‐geminate charge carrier recombination of the holes in the Si‐PCPDTBT phase with electrons in the PC61BM phase, both processes being of diffusive nature. At excitation densities corresponding to steady state conditions under one sun, modelling predicts hole transfer efficiencies exceeding 90%, in accordance with IQE measurements. At higher pump intensities, bimolecular recombination suppresses the hole transfer process effectively. 相似文献
83.
Alkyl Chain Engineering of Solution‐Processable Star‐Shaped Molecules for High‐Performance Organic Solar Cells
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Jie Min Yuriy N. Luponosov Andreas Gerl Marina S. Polinskaya Svetlana M. Peregudova Petr V. Dmitryakov Artem V. Bakirov Maxim A. Shcherbina Sergei N. Chvalun Souren Grigorian Nina Kaush‐Busies Sergei A. Ponomarenko Tayebeh Ameri Christoph J. Brabec 《Liver Transplantation》2014,4(5)
The impact of alkyl side‐chain substituents on conjugated polymers on the photovoltaic properties of bulk heterojunction (BHJ) solar cells has been studied extensively, but their impact on small molecules has not received adequate attention. To reveal the effect of side chains, a series of star‐shaped molecules based on a triphenylamine (TPA) core, bithiophene, and dicyanovinyl units derivatized with various alkyl end‐capping groups of methyl, ethyl, hexyl and dodecyl is synthesiyed and studied to comprehensively investigate structure‐properties relationships. UV‐vis absorption and cyclic voltammetry data show that variations of alkyl chain length have little influence on the absorption and highest occupied molecular orbital (HOMO)‐lowest unoccupied molecular orbital (LUMO) levels. However, these seemingly negligible changes have a pronounced impact on the morphology of BHJ thin films as well as their charge carrier separation and transportation, which in turn influences the photovoltaic properties of these small‐molecule‐based BHJ devices. Solution‐processed organic solar cells (OSCs) based on the small molecule with the shortest methyl end groups exhibit high short circuit current (Jsc) and fill factor (FF), with an efficiency as high as 4.76% without any post‐treatments; these are among the highest reported for solution‐processed OSCs based on star‐shaped molecules. 相似文献
84.
Ann Chahroudi Emily Cartwright S. Thera Lee Maud Mavigner Diane G. Carnathan Benton Lawson Paul M. Carnathan Tayebeh Hashempoor Megan K. Murphy Tracy Meeker Stephanie Ehnert Christopher Souder James G. Else Joyce Cohen Ronald G. Collman Thomas H. Vanderford Sallie R. Permar Cynthia A. Derdeyn Francois Villinger Guido Silvestri 《PLoS pathogens》2014,10(3)
Mother-to-infant transmission (MTIT) of HIV is a serious global health concern, with over 300,000 children newly infected in 2011. SIV infection of rhesus macaques (RMs) results in similar rates of MTIT to that of HIV in humans. In contrast, SIV infection of sooty mangabeys (SMs) rarely results in MTIT. The mechanisms underlying protection from MTIT in SMs are unknown. In this study we tested the hypotheses that breast milk factors and/or target cell availability dictate the rate of MTIT in RMs (transmitters) and SMs (non-transmitters). We measured viral loads (cell-free and cell-associated), levels of immune mediators, and the ability to inhibit SIV infection in vitro in milk obtained from lactating RMs and SMs. In addition, we assessed the levels of target cells (CD4+CCR5+ T cells) in gastrointestinal and lymphoid tissues, including those relevant to breastfeeding transmission, as well as peripheral blood from uninfected RM and SM infants. We found that frequently-transmitting RMs did not have higher levels of cell-free or cell-associated viral loads in milk compared to rarely-transmitting SMs. Milk from both RMs and SMs moderately inhibited in vitro SIV infection, and presence of the examined immune mediators in these two species did not readily explain the differential rates of transmission. Importantly, we found that the percentage of CD4+CCR5+ T cells was significantly lower in all tissues in infant SMs as compared to infant RMs despite robust levels of CD4+ T cell proliferation in both species. The difference between the frequently-transmitting RMs and rarely-transmitting SMs was most pronounced in CD4+ memory T cells in the spleen, jejunum, and colon as well as in central and effector memory CD4+ T cells in the peripheral blood. We propose that limited availability of SIV target cells in infant SMs represents a key evolutionary adaptation to reduce the risk of MTIT in SIV-infected SMs. 相似文献
85.
We analyzed the levels of genetic variability in a long-distance migratory reed warbler, the Marsh Warbler Acrocephalus palustris, by using nucleotide sequences of the mitochondrial cytochrome c oxidase subunit I gene (COI; 611 nucleotides [nt]). We obtained sequences from 229 individuals from ten sampling sites that include breeding, wintering, and migrating birds. Overall, 44 haplotypes were detected, which reflect high levels of genetic variation in this species, but most of this variation corresponds to individual differences within collecting sites. We also analyzed 829 nt of cytochrome b (cyt b) from 49 selected individuals of different sampling sites to evaluate the reliability of the COI results. Our analyses based on both mtDNA loci could not detect any population subdivision or phylogeographic structure, indicating high levels of gene flow between breeding sites (Nm?=?13.69). The split between the Marsh Warbler and its sister species, the Eurasian Reed Warbler Acrocephalus scirpaceus, could be dated for the Lower Pliocene (about 3.8 million years ago). The time to the most recent common ancestor (TMRCA) among Marsh Warbler haplotypes was estimated as 0.45 million years, indicating their bottleneck during the last glacial periods. Low nucleotide diversity, a shallow phylogenetic tree, a star-like haplotype network, and a unimodal mismatch distribution point to a sudden increase of the effective population size (probably after the last glaciation period) and a recent range expansion likely from a single refuge. 相似文献
86.
Safa Tahmasebi Maytham T. Qasim Maria V. Krivenkova Angelina O. Zekiy Lakshmi Thangavelu Surendar Aravindhan Morteza Izadi Farhad Jadidi-Niaragh Mahnaz Ghaebi Saeed Aslani Leili Aghebat-Maleki Majid Ahmadi Leila Roshangar 《Cell biology international》2021,45(7):1498-1509
Multiple sclerosis (MS) is a common degenerative disorder of the central nervous system. The decreased frequency and dysfunction of Treg cells cause inflammation and disease progression. Ozone autohemotherapy can be used as a potential therapeutic approach to regulate the immune system responses and inflammation in MS. For this purpose, 20 relapsing-remitting multiple sclerosis patients were under treatment with ozone twice weekly for 6 months. The frequency of Treg cell, the expression levels of the Treg cell-related factors (FoxP3, IL-10, TGF-β, miR-17, miR-27, and miR-146A), and the secretion levels of IL-10 and TGF-β were assessed. We found a significant increase in the number of Treg cells, expression levels of FoxP3, miRNAs (miR-17 and miR-27), IL-10, and TGF-β factors in patients after oxygen–ozone (O2-O3) therapy compared to before treatment. In contrast, oxygen–ozone therapy notably decreased the expression level of miR-146a in treated patients. Interestingly, the secretion levels of both IL-10 and TGF-β cytokines were considerably increased in both serum and supernatant of cultured peripheral blood mononuclear cells in posttreatment condition compared to pretreatment condition. According to results, oxygen–ozone therapy raised the frequency of Treg cell and its relevant factors in treated MS patients. Oxygen–ozone therapy would contribute to improving the MS patients by elevating the Treg cell responses. 相似文献
87.
Mohamad Ali Roozegar Tayebeh Malek Mohammadi Mohamad Reza Havasian Jafar Panahi Amirreza Hashemian Mansur Amraei Behzad Hoshmand 《Bioinformation》2015,11(2):96-100
Periodontium is a complex organ composed of mineralized epithelial and connective tissue. Dexamethasone could stimulate
proliferation of osteoblast and fibroblasts. This study aimed to assess the osteogenic effect of dexamethasone on periodental
ligament (PDL) stem cells. PDL stem cells were collected from periodontal ligament tissue of root of extracted premolar of young
and healthy people. The stem cells were cultured in α-MEM Medium in three groups, one group with basic medium contains (α-
MEM and FBS 10 % and 50 mmol of β_ gelisrophosphat and L_ ascorbic acid µg/ml), the second group: basic medium with
dexamethasone and the third one: basic medium without any osteogenic stimulant. Mineralization of cellular layer was analyzed
with Alizarin red stain method. Osteogenic analysis was done by Alkaline phosphates and calcium test. These analysis indicated
that the amount of intra-cellular calcium and alkaline phosphates in the Dexamethasone group was far more than the control and
basic group (P<0.05). The results of Alizarin red stain indicated more mineralization of cultured cells in Dexamethasone group
(P<0.05). The study results showed that Dexamethasone has significant osteogenic effect on PDL stem cells and further studies are
recommended to evaluate its effect on treatment of bone disorders. 相似文献
88.
Alizadeh A Samih MA Izadi H 《Communications in agricultural and applied biological sciences》2007,72(4):1011-1015
The entomopathogenic fungus, Verticillium lecanii (Zimm.) Viégas is a widespread hyphomycete consisting of a heterogeneous species aggregate. Conidia survival may be effected by environmental factors or by bio-pesticides and chemical products used to protect crop plants. In this research compatibility of mentioned fungi with imidachlopride, flufenoxuron, teflubenzuron+phozalone, endosulfan, amitraz, and effect of these pesticides on vegetative growth of the fungus were studied. The formulations of pesticides were tested in three concentration (mean concentration-MC, half MC and twice the MC) and using Duncan multiple range test, treatment were grouped. Effects of the pesticides on V. lecanii vegetative growth in concerned results have shown that almost all formulations studies significantly inhibition fungal development. The results indicated that flufenoxuron (at three concentrations), teflubenzuron+phozalone (at MC and twice the MC), induced levels of vegetative growth inhibition higher than 68%. Only data on amitraz and imidachlopride (at half MC) were not significantly different from the control, which is indicated the compatible formulations with V. lecanii. These formulations could be used simultaneously with this entomopathogenic in integrated pest management. 相似文献
89.
90.
Effects of Alkyl Terminal Chains on Morphology,Charge Generation,Transport, and Recombination Mechanisms in Solution‐Processed Small Molecule Bulk Heterojunction Solar Cells
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Jie Min Yuriy N. Luponosov Nicola Gasparini Moses Richter Artem V. Bakirov Maxim A. Shcherbina Sergei N. Chvalun Linda Grodd Souren Grigorian Tayebeh Ameri Sergei A. Ponomarenko Christoph J. Brabec 《Liver Transplantation》2015,5(17)
Length of the terminal alkyl chains at dicyanovinyl (DCV) groups of two dithienosilole (DTS) containing small molecules ( DTS(Oct)2‐(2T‐DCV‐Me)2 and DTS(Oct)2‐(2T‐DCV‐Hex)2 ) is investigated to evaluate how this affects the molecular solubility and blend morphology as well as their performance in bulk heterojunction organic solar cells (OSCs). While the DTS(Oct)2‐(2T‐DCV‐Me)2 (a solubility of 5 mg mL?1) system exhibits both high short circuit current density (J sc) and high fill factor, the DTS(Oct)2‐(2T‐DCV‐Hex)2 (a solubility of 24 mg mL?1) system in contrast suffers from a poor blend morphology as examined by atomic force morphology and grazing incidence X‐ray scattering measurements, which limit the photovoltaic properties. The charge generation, transport, and recombination dynamics associated with the limited device performance are investigated for both systems. Nongeminate recombination losses in DTS(Oct)2‐(2T‐DCV‐Hex)2 system are demonstrated to be significant by combining space charge limited current analysis and light intensity dependence of current–voltage characteristics in combination with photogenerated charge carrier extraction by linearly increasing voltage and transient photovoltage measurements. DTS(Oct)2‐(2T‐DCV‐Me)2 in contrast performs nearly ideal with no evidence of nongeminate recombination, space charge effects, or mobility limitation. These results demonstrate the importance of alkyl chain engineering for solution‐processed OSCs based on small molecules as an essential design tool to overcome transport limitations. 相似文献