Exploring wide bandgap metal oxides for perovskite solar cells

The heterojunction formed when wide bandgap oxides come into contact with perovskite solar cells is essential for high efficiency as it minimizes charge leakage along with charge separation and charge transfer. Therefore, the electrical and optical properties of wide bandgap oxides, including the bandgap, charge mobility, and energy level, directly determine the efficiency of perovskite solar cells. In addition, the surface properties of the wide bandgap oxide act as an important factor that determines the efficiency through the wettability and penetration of the precursor solution during perovskite layer deposition and long-term stability through the intimate interfacial bonding with the perovskite. Although a great variety of wide bandgap oxides are known, the number that can be used for perovskite solar cells is considerably reduced in view of the limitations that the light absorber (here, perovskite) for solar cells is fixed, and the oxides must be uniformly coated at low temperature onto the substrate. Herein, a review of the results from several broad bandgap oxides used in perovskite solar cells is presented, and a direction for discovering new photoelectrodes is proposed

Energy- and Time-Dependent Branching to Competing Paths in Coupled Unimolecular Dissociations of Chlorotoluene Radical Cations

The energy- and time-dependent branching to the competing dissociation paths are studied by theory for coupled unimolecular dissociations of the o-, m-, and p-chlorotoluene radical cations to C7H7+ (benzylium and tropylium). There are four different paths to C7H7+, three to the benzylium ion and one to the tropylium ion, and all of them are coupled together. The branching to the multiple paths leads to the multiexponential decay of reactant with the branching ratio depending on both internal energy and time. To gain insights into the multipath branching, we study the detailed kinetics as a function of time and internal energy on the basis of ab inito/RRKM calculations. The number of reaction steps to C7H7+ is counted for each path. Of the three isomers, the meta mostly goes through the coupling, whereas the para proceeds with little or no coupling. In the beginning, some reactants with high internal energy decay fast to the benzylium ion without any coupling and others rearrange to the other isomers. Later on all three isomers dissociate to the products via long-lived intermediates. Thus, the reactant shows a multiexponential decay and the branching ratio varies with time as the average internal energy decreases with time. The reciprocal of the effective lifetime is taken as the rate constant. The resulting rate-energy curves are in line with experiments. The present results suggest that the coupling between the stable isomers is thermodynamically controlled, whereas the branching to the product is kinetically controlled.X1111Ysciescopu

Cisplatin induces tolerogenic dendritic cells in response to TLR agonists via the abundant production of IL-10, thereby promoting Th2-and Tr1-biased T-cell immunity

Although many advantageous roles of cisplatin (cis-diamminedichloroplatinum (II), CDDP) have been reported in cancer therapy, the immunomodulatory roles of cisplatin in the phenotypic and functional alterations of dendritic cells (DCs) are poorly understood. Here, we investigated the effect of cisplatin on the functionality of DCs and the changes in signaling pathways activated upon toll-like receptor (TLR) stimulation. Cisplatin-treated DCs down-regulated the expression of cell surface molecules (CD80, CD86, MHC class I and II) and up-regulated endocytic capacity in a dose-dependent manner. Upon stimulation with various TLR agonists, cisplatin-treated DCs showed markedly increased IL-10 production through activation of the p38 MAPK and NF-kappa B signaling pathways without altering the levels of TNF-alpha and IL-12p70, indicating the cisplatin-mediated induction of tolerogenic DCs. This effect was dependent on the production of IL-10 from DCs, as neither DCs isolated from IL-10(-/-) mice nor IL-10-neutralized DCs generated tolerogenic DCs. Interestingly, DCs that were co-treated with cisplatin and lipopolysaccharide (LPS) exhibited a decreased immunostimulatory capacity for inducing the proliferation of Th1- and Th17-type T cells; instead, these DCs contributed to Th2-type T cell immunity. Furthermore, in vitro and in vivo investigations revealed a unique T cell population, IL-10-producing CD3(+)CD4(+)LAG-3(+)CD49b(+)CD25(-)Foxp3(-) Tr1 cells, that was significantly increased without altering the Foxp3(+) regulatory T cell population. Taken together, our results suggest that cisplatin induces immune-suppressive tolerogenic DCs in TLR agonist-induced inflammatory conditions via abundant IL-10 production, thereby skewing Th cell differentiation towards Th2 and Tr1 cells. This relationship may provide cancer cells with an opportunity to evade the immune system.1123Ysciescopu

Cisplatin induces tolerogenic dendritic cells in response to TLR agonists via the abundant production of IL-10, therby promoting Th2- and Tr1-biased T-cell immunity

Although many advantageous roles of cisplatin (cis-diamminedichloroplatinum (II), CDDP) have been reported in cancer therapy, the immunomodulatory roles of cisplatin in the phenotypic and functional alterations of dendritic cells (DCs) are poorly understood. Here, we investigated the effect of cisplatin on the functionality of DCs and the changes in signaling pathways activated upon toll-like receptor (TLR) stimulation. Cisplatin-treated DCs down-regulated the expression of cell surface molecules (CD80, CD86, MHC class I and II) and up-regulated endocytic capacity in a dose-dependent manner. Upon stimulation with various TLR agonists, cisplatintreated DCs showed markedly increased IL-10 production through activation of the p38 MAPK and NF-κB signaling pathways without altering the levels of TNF-α and IL- 12p70, indicating the cisplatin-mediated induction of tolerogenic DCs. This effect was dependent on the production of IL-10 from DCs, as neither DCs isolated from IL-10- /- mice nor IL-10-neutralized DCs generated tolerogenic DCs. Interestingly, DCs that were co-treated with cisplatin and lipopolysaccharide (LPS) exhibited a decreased immunostimulatory capacity for inducing the proliferation of Th1- and Th17-type T cells; instead, these DCs contributed to Th2-type T cell immunity. Furthermore, in vitro and in vivo investigations revealed a unique T cell population, IL-10-producing CD3+CD4+LAG-3+CD49b+CD25-Foxp3- Tr1 cells, that was significantly increased without altering the Foxp3+ regulatory T cell population. Taken together, our results suggest that cisplatin induces immune-suppressive tolerogenic DCs in TLR agonistinduced inflammatory conditions via abundant IL-10 production, thereby skewing Th cell differentiation towards Th2 and Tr1 cells. This relationship may provide cancer cells with an opportunity to evade the immune system.1231sciescopu

A study on fire design accidental loads for aluminum safety helidecks

The helideck structure must satisfy the safety requirements associated with various environmental and accidental loads. Especially, there have been a number of fire accidents offshore due to helicopter collision (take-off and/or landing) in recent decades. To prevent further accidents, a substantial amount of effort has been directed toward the management of fire in the safety design of offshore helidecks. The aims of this study are to introduce and apply a procedure for quantitative risk assessment and management of fires by defining the fire loads with an applied example. The frequency of helicopter accidents are considered, and design accidental levels are applied. The proposed procedures for determining design fire loads can be efficiently applied in offshore helideck development projects

The 'Signature' of Particle Geometry - DEM Modelling Perspective

This study evidences that the particle surface-area-to-volume ratio (A/V) and the particle volume (V) have the key information of particle geometry and the ‘signature’ is realized by a power-law relationship between A/V and V in a form of V = (A/V)α × β. We find that the power value α is influenced by the shape-size relationship while the β* term (β evaluated with a fixed value of α = -3) informs the average particle shape of a granular material regarding the overall angularity. This study also discusses how the particle shape can be retrieved in terms of Wadell’s true sphericity using the A/V and V. This concept is linked to another shape index M that interprets the particle shape as a function of surface area A, volume V, and size L. This paper explains the analytical aspects of geometric ‘signature’ and examines the idea using the example particles to address the DEM modelling-related questions

Effect of amorphous Si quantum-dot size on 1.54 μm luminescence of Er

The role of the size of amorphous silicon quantum dots in the Er luminescence at 1.54 μm was investigated. As the dot size was increased, more Er ions were located near one dot due to its large surface area and more Er ions interacted with other ones. This Er-Er interaction caused a weak photoluminescence intensity, despite the increase in the effective excitation cross section. The critical dot size needed to take advantage of the positive effect on Er luminescence is considered to be about 2.0 nm, below which a small dot is very effective in the efficient luminescence of Er. © 2005 The Electrochemical Society. All rights reserved

Euler diagrams through the looking glass: From extent to intent

Extension and intension are two ways of indicating the fundamental meaning of a concept. The extent of a concept, C, is the set of objects which correspond to C whereas the intent of C is the collection of attributes that characterise it. Thus, intension denotes the set of objects corresponding to C without naming them individually. Mathematicians switch comfortably between these perspectives but the majority of logical diagrams deal exclusively in extension. Euler diagrams indicate sets using curves to depict their extent in a way that intuitively matches the relations between the sets. What happens when we use spatial diagrams to depict intension? What can we infer about the intension of a concept given its extension, and vice versa? We present the first steps towards addressing these questions by defining extensional and intensional Euler diagrams and translations between the two perspectives. We show that translation in either direction leads to a loss of information, yet preserves important semantic properties. To conclude, we explain how we expect further exploration of the relationship between the two perspectives could shed light on connections between diagrams, extension, intension, and well-matchedness