The optical emission characteristics of biaxially compressed InAsxP1−x/InP strained single quantum well (QW) structures, with nominal compositionx=0.67, have been investigated using photoluminescence (PL) and photoluminescence excitation (PLE) spectroscopies. The highly
strained QWs exhibit intense and narrow PL in the 0.9–1.5 μm wavelength range, similar to the lattice-matched InGaAs(P)/InP
system. The 20 K PLE spectra exhibit well-resolved features attributed ton=1 heavy hole (E1H1) and light hole (E1L1) transitions in the 1.0–1.5 μm wavelength range. In addition, features attributed
to transitions betweenn=2 electrons and heavy holes (E2H2), and betweenn=1 electrons and unconfined holes (E1Hf), were observed. The energy splitting between the heavy-hole and light-hole bands
was found to be a sensitive measure of the band offsets in the system. The best prediction of this splitting was obtained
for a valence band offset of δEV∼0.25δEG. This value of band offset was in agreement with the energy position of the E1Hf transition. The observed transition energies
were also compared with the results of a finite square well model, taking into account the effects of strain, and the results
offer further support for the band offset assignment. This study indicates that the InAsP system may be advantageous for application
in strained-layer optoelectronic devices operating in the 1.3–1.6 μm wavelength range. 相似文献
Structural elements combining Ultra-High Performance Fiber Reinforced Concretes (UHPFRC) and concrete offer a high potential
in view of rehabilitation and modification of existing structures. The investigation of the time-dependent behavior of composite
“UHPFRC-concrete” elements is a fundamental step in the determination of durability and serviceability. For this, an experimental
program was conducted on large composite “UHPFRC-concrete” beams and a numerical model was validated with the test results.
The experimental results and a parametric study performed with the numerical model showed that UHPFRC and normal strength
reinforced concrete are compatible in the long-term and that the critical period of composite “UHPFRC-concrete” elements are the first 90 days after the casting of the UHPFRC layer. Thus, the high potential
of such composite elements can be exploited also in the long term. 相似文献
The primary purpose of this paper is to show an efficient way of handling models and model data in a decision support system, in which it is usual to consider several variants of a model. The model data primarily consist of model-defining data, but the same approach may be used for the generated results as well. By efficient handling is meant the handling by the computer as well as by the user. For the user it is particularly important that new models can be conveniently defined as variants of existing models. The approach is introduced within the context of a decision support system for manpower planning based on Markov models. In the mean time the same approach has been used for the implementation of other decision support systems and has been found to be more generally applicable. 相似文献
This article explores the relationships between academic knowledge and the practice of research in the construction of new computer-supported research tools for e-social science. The article draws on a U.K. e-social science pilot demonstrator project, "Collaborative Analysis of Offenders' Personal and Area-based Social Exclusion," that explores the relative impact of individual and neighborhood effects on geographical crime patterns. Three main dimensions of e-social science are addressed by the project: (1) identification of new social research foci, (2) adapting research processes, and (3) developing Grid-related research tools. The integration of these dimensions shows that research-driven and user-led development of computer-mediated research using the Grid can produce relevant and innovative tools for the social sciences. 相似文献
Melanoma is the deadliest form of skin cancer and accounts for about three quarters of all skin cancer deaths. Especially at an advanced stage, its treatment is challenging, and survival rates are very low. In previous studies, we showed that the constituents of the roots of Onosma paniculata as well as a synthetic derivative of the most active constituent showed promising results in metastatic melanoma cell lines. In the current study, we address the question whether we can generate further derivatives with optimized activity by synthesis. Therefore, we prepared 31, mainly novel shikonin derivatives and screened them in different melanoma cell lines (WM9, WM164, and MUG-Mel2 cells) using the XTT viability assay. We identified (R)-1-(1,4-dihydro-5,8-dihydroxy-1,4-dioxonaphthalen-2-yl)-4-methylpent-3-enyl 2-cyclopropyl-2-oxoacetate as a novel derivative with even higher activity. Furthermore, pharmacological investigations including the ApoToxGloTM Triplex assay, LDH assay, and cell cycle measurements revealed that this compound induced apoptosis and reduced cells in the G1 phase accompanied by an increase of cells in the G2/M phase. Moreover, it showed hardly any effects on the cell membrane integrity. However, it also exhibited cytotoxicity against non-tumorigenic cells. Nevertheless, in summary, we could show that shikonin derivatives might be promising drug leads in the treatment of melanoma. 相似文献
Indoleamine-2,3-dioxygenase 1 (IDO1) is a heme-containing enzyme that catalyzes the rate-limiting step in the kynurenine pathway of tryptophan (TRP) metabolism. As it is an inflammation-induced immunoregulatory enzyme, pharmacological inhibition of IDO1 activity is currently being pursued as a potential therapeutic tool for the treatment of cancer and other disease states. As such, a detailed understanding of the mechanism of action of IDO1 inhibitors with various mechanisms of inhibition is of great interest. Comparison of an apo-form-binding IDO1 inhibitor (GSK5628) to the heme-coordinating compound, epacadostat (Incyte), allows us to explore the details of the apo-binding inhibition of IDO1. Herein, we demonstrate that GSK5628 inhibits IDO1 by competing with heme for binding to a heme-free conformation of the enzyme (apo-IDO1), whereas epacadostat coordinates its binding with the iron atom of the IDO1 heme cofactor. Comparison of these two compounds in cellular systems reveals a long-lasting inhibitory effect of GSK5628, previously undescribed for other known IDO1 inhibitors. Detailed characterization of this apo-binding mechanism for IDO1 inhibition might help design superior inhibitors or could confer a unique competitive advantage over other IDO1 inhibitors vis-à-vis specificity and pharmacokinetic parameters. 相似文献
Analytical Characterisation of Palm Oil Fractions by HPLC of Triglycerides The increasing importance of palm oils and palm oil fractions in international trade makes it necessary to develop analytical criteria for the characterisation of these products. One problem is the correct identification of palm oleins, which are often difficult to distinguish from palm oils. These products frequently exhibit similar fatty acid by GLC and similar iodine values. The correct identification of palm stearins by GLC is comparatively more easy. Palm oleins and palm oils can be characterized by HPLC using conditions that permit not only the separation of triolein from less unsaturated triglycerides of the same carbon number, but also, at the same time, a separation of tripalmitin from triglycerides containing oleic acid. By establishing the peak area ratios for a number of selected triglycerides a clear differentiation between palm oils and palm oleins, as well as various other palm oil fractions and their mixtures is obtained. 相似文献
Elastomer materials are used in a wide application range and subjected to different loading from which failure of the material results. Because this failure is caused by initiation and propagation of cracks, the application of fracture mechanics methods for the assessment of the material is obvious. A short summary of the methods of technical fracture mechanics including possibilities of determination of crack resistance curves is given. Vulcanizates on the basis of SBR 1500 with various sulfur and carbon black contents were investigated. For describing the crack initiation and crack propagation behavior, several fracture mechanics examination methods were applied. Tear‐analyzer results were used to assess the crack propagation behavior under fatigue‐like loading conditions. Furthermore, for the characterization of the crack resistance of the materials under impact‐like loading conditions, instrumented tensile‐impact tests were performed. To obtain information about the initiation and propagation of a stable crack, quasi‐static fracture mechanics tests were applied. The results of the several tests are discussed in dependence on sulfur and carbon black contents. We found a non‐monotonous behavior of the toughness as a function of carbon black loading. An explanation is given in connection with a percolation‐like transition in filler morphology on larger length scales.
Schematic crack propagation curve for characterizing the fatigue behavior of the vulcanizates recorded in a TFA test. 相似文献
MALDI-TOF MS profiling for microorganism detection has already been demonstrated in the 1990s, but has evolved to the first-line identification method in many laboratories just during the past five years. While this application of MALDI-TOF MS has proven its broad applicability, accuracy, robustness, and cost-effectiveness it is of particular interest to expand the capabilities of the mass spectrometric platform. Resistance detection is the most desirable further application of MALDI-TOF MS in microbiology, but maybe also the most challenging. Different approaches have been published regarding diverse antibiotic drugs and distinct microorganism classes. The current review shall give an overview about the developments of the recent years and their potential to get transformed in clinical useful assays in the future. 相似文献