The number of studies on organic–inorganic hybrid perovskites has soared in recent years. However, the majority of hybrid perovskites under investigation are based on a limited number of organic ...cations of suitable sizes, such as methylammonium and formamidinium. These small cations easily fit into the perovskite's three‐dimensional (3D) lead halide framework to produce semiconductors with excellent charge transport properties. Until now, larger cations, such as ethylammonium, have been found to form 2D crystals with lead halide. Here we show for the first time that ethylammonium can in fact be incorporated coordinately with methylammonium in the lattice of a 3D perovskite thanks to a balance of opposite lattice distortion strains. This inclusion results in higher crystal symmetry, improved material stability, and markedly enhanced charge carrier lifetime. This crystal engineering strategy of balancing opposite lattice distortion effects vastly increases the number of potential choices of organic cations for 3D perovskites, opening up new degrees of freedom to tailor their optoelectronic and environmental properties.
Despite its large ionic radius, ethylammonium can partially replace methylammonium in the widely studied 3D hybrid perovskites CH3NH3PbI3. This partial replacement results in higher crystal symmetry, improved material stability, and markedly enhanced photocarrier lifetime of the alloy perovskites.
The levels of beta 1H and C3bINA were estimated in sera from human fetuses, cord and maternal samples. Both components of complement were detected in fetuses more than 12 weeks old. The serum ...concentrations tended to increase with the gestational age. The mean levels of beta 1H and C3bINA in cord sera were near 54 and 61% of the mean values in sera from normal adults. Elevated levels of beta 1H were observed in maternal sera at the end of the gestational period. When the levels of beta 1H and C3bINA were compared with those of two other components of complement, it was confirmed that the mean levels of C9 were low in fetal and newborn sera, while the serum concentrations of both C9 and Factor B were elevated in maternal samples. Newly synthesised beta 1H was detected in the culture fluids of fetal liver and peritoneal cells, as judged by the incorporation of labelled aminoacids and the autoradiography of he specific immunoprecipitates in agar gel.
A further component of the glycoside mixture extracted from the bulbs of Muscaricomosum has been completely characterized by chemical degradative study and spectral investigation. This glycoside,
2
, ...termed muscaroside B, possesses an α-
L
-arabinofuranosyl(1 → 2)-α-
L
-arabinopyranosyl(1 → 3)α-
L
-rhamnopyranosyl(1 → 2)-β-
D
-glucopyranosyl(1 → 2)-α-
L
-arabinopyranosyl(1 → 6)-β-
D
-glucopyranosyl chain linked at the 3-position of eucosterol.
•The influence of temperature on DC–DC converter devices properties is considered.•An electro-thermal design method for PV power optimizer converters is proposed.•The electro-thermal design method ...proposed is applied to DR boost and SR boost.•Efficiency results of the designed SR converter and DR converters are presented.
Photovoltaic (PV) systems can operate in presence of not uniform working conditions caused by continuously changing temperature and irradiance values and mismatching and shadowing phenomena. The more the PV system works in these conditions, the more its energy performances are negatively affected. Distributed Maximum Power Point Tracking (DMPPT) converters are now increasingly used to overcome this problem and to improve PV applications efficiency. A DMPPT system consists in a DC–DC converters equipped with a suitable controller dedicated to the Maximum Power Point Tracking (MPPT) of a single PV module. It is arranged either inside the junction-box or in a separate box close to the PV generator. Many power optimizers are now commercially available. In spite of different adopted DC–DC converter topologies, the shared interests of DMPPT systems designers are the high efficiency and reliability values. It is worth noting that to obtain so high performances converters, electronic components have to be carefully selected between the whole commercial availability and appropriately matched together. In this scenario, an electro-thermal design methodology is proposed and a reliability study by means of the Military Handbook 217F is carried out.
The developed DMPPT converters design method is constituted by many steps. In fact, beginning from installation site, PV generators and load data, this process selects power optimizers commercially available devices and it verifies their electro-thermal behavior to the aim to identify a set of suitable components for DMPPT applications. Repeating this process many times, many different feasible solutions can be found. An elaboration step follows to the “optima” power optimizer recognition among the whole obtained converters. In this case, a multi-objective optimization, consisting in the maximization of the solutions European efficiency and in the minimization of their cost, is executed and all not dominated solutions with respect to at least one of the two objectives are selected. The strength of the described method is represented by accurate PV generators and optimizer devices models. In detail, in the developed models particular attention is reserved to the thermal factor and to the quantification of the temperature action on devices parameters and performances. In fact, in such multiple and continuous changing working conditions, the temperature influence on components behavior can considerably vary their properties causing the whole converter performances worsening. The other important aspect, the converter reliability, is estimated by the reliability prediction model Military Handbook 217F.
The proposed tool is applied to Diode Rectification (DR) boosts and Synchronous (SR) boosts design. To completely characterize the obtained solutions their efficiency, cost and reliability performances are evaluated. In detail, Pareto fronts in terms of European efficiency and cost are identified for the SR and DR cases. Among the whole not dominated solutions, a SR converter characterized by a European efficiency of 97.1% and a DR boost characterized by a European efficiency of 95.5% are chosen. Their cost is comparable and equal about to $11. Then their reliability performances are evaluated by means of the Military Handbook 217F Notice 2. The carried out analysis shows that, for the same device cost, the SR solution represents the best one if efficiency is the most critical aspect. DR boost is, instead, the optimum solution if reliability represents the tighter requirement.
The proposed DMPPT converters methodology permits to design families of feasible power optimizers. This process is applied to two boost versions, so two sets of power optimizers are obtained and a trade-off solution is chosen for each set. To correctly select the more suitable optimizer, a characterization in terms of efficiency, cost and reliability is carried out. In detail, the SR optimizer is characterized by lower losses and higher efficiency than the DR one. On the other hand, the DR boost results more reliable than the SR converter. So the optimum solution has to be chosen on the base of the most critical requirement.
The developed method can represent a useful tool to design DMPPT optimizers able to assure high level performances in terms of economical and technical aspects. It can be applied to many commercially available PV generators and, without loss of generality, it can be used with different DC–DC converter topologies.
Aldo-keto reductase 1C3 (AKR1C3) is an attractive target in drug design for its role in resistance to anticancer therapy. Several nonsteroidal anti-inflammatory drugs such as indomethacin are known ...to inhibit AKR1C3 in a nonselective manner because of COX-off target effects. Here we designed two indomethacin analogues by proposing a bioisosteric connection between the indomethacin carboxylic acid function and either hydroxyfurazan or hydroxy triazole rings. Both compounds were found to target AKR1C3 in a selective manner. In particular, hydroxyfurazan derivative is highly selective for AKR1C3 over the 1C2 isoform (up to 90-times more) and inactive on COX enzymes. High-resolution crystal structure of its complex with AKR1C3 shed light onto the binding mode of the new inhibitors. In cell-based assays (on colorectal and prostate cancer cells), the two indomethacin analogues showed higher potency than indomethacin. Therefore, these two AKR1C3 inhibitors can be used to provide further insight into the role of AKR1C3 in cancer.
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