21 research outputs found
A Gene Encoding Sialic-Acid-Specific 9-O-Acetylesterase Found in Human Adult Testis
Using differential display RT-PCR, we identified a gene of 2750 bp from human adult testis, named H-Lse, which encoded a putative protein of 523 amino acids and molecular weight of 58 kd with structural characteristics similar to that of mouse lysosome sialic-acid-specific 9-O-acetylesterase. Northern blot analysis showed a widespread distribution of H-Lse in various human tissues with high expression in the testis, prostate, and colon. In situ hybridization results showed that while H-Lse was not detected in embryonic testis, positive signals were found in spermatocytes but not spermatogonia in adult testis of human. The subcellular localization of H-Lse was visualized by green fluorescent protein (GFP) fused to the amino terminus of H-Lse, showing compartmentalization of H-Lse in large dense-core vesicles, presumably lysosomes, in the cytoplasm. The developmentally regulated and spermatogenic stage-specific expression of H-Lse suggests its possible involvement in the development of the testis and/or differentiation of germ cells
Highly efficient blueish-green fluorescent OLEDs based on AIE liquid crystal molecules : From ingenious molecular design to multifunction materials
In order to seek the balance point between liquid crystallinity and high efficiency emission, two novel aggregation-induced emission-based (AIE) liquid crystal materials of TPE-PBN and TPE-2PBN, which contain a tetraphenylethene derivative as the emission core and a 4-cynobiphenyl moiety as the mesogenic unit, were designed and prepared. Both simple molecules showed a mesophase at high temperature as evidenced by polarised optical microscopy (POM), differential scanning calorimetry (DSC) and temperature-dependent X-ray diffraction (XRD). Simultaneously, TPE-PBN and TPE-2PBN presented clear AIE characteristics in the blueish-green region and achieved a high emission quantum efficiency of 71% and 83% in the solid state, respectively. Due to the self-assembly properties of thermotropic liquid crystals, both compounds showed higher hole mobilities in the annealed films than in pristine films. Employing TPE-PBN and TPE-2PBN as the emitting materials, both non-doped devices and doped devices were fabricated. The TPE-PBN-based doped OLEDs showed a better device performance with an external quantum efficiency (EQE) of 4.1% which is among the highest EQEs of blue AIE fluorescent OLEDs
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The Output Cost of Gender Discrimination: A Model-based Macroeconomics Estimate
We use a growth model in which saving, fertility and labour market participation are endogenous, to quantify the cost that barriers to female labour force participation impose in terms of an economy’s output. The model is calibrated to mimic the U.S. economy’s behavior in the long-run. We find that a 50 percent increase in the gender wage gap leads to a 35 percent decrease in income per capita in steady-state. Using independent estimates of the female to male earnings ratio for a wide cross-section of countries, we construct an economy with parameters similar to those calibrated for the U.S. economy, except for the degree of gender barriers.
Higher discrimination decreases steady-state output per capita for two distinct reasons: a direct effect due to the decrease in female labour market participation, and an indirect effect working through an increase in fertility. For several countries, a large fraction of the difference between
the country’s output and U.S. output can be ascribed to differences in gender discrimination. In addition, we find that close to half of the overall decrease in output per capita is due to the effect of gender discrimination in fertility.This paper has benefited from the financial support from Egide and Nova Forum at Universidade Nova de Lisboa, from the Funda¸cao para Ciencia e Tecnologia (FCT) and POCTI through FEDER, and from the Conselho Nacional de Desenvolvimento Cientıfico e Tecnologico (CNPq-Brazil)
Critical Role of TCF-1 in Repression of the IL-17 Gene
Overwhelming activation of IL-17, a gene involved in inflammation, leads to exaggerated Th17 responses associated with numerous autoimmune conditions, such as experimental autoimmune encephalomyelitis (EAE). Here we show that TCF-1 is a critical factor to repress IL-17 gene locus by chromatin modifications during T cell development. Deletion of TCF-1 resulted in increased IL-17 gene expression both in thymus and peripheral T cells, which led to enhanced Th17 differentiation. As a result, TCF-1-/- mice were susceptible to Th17-dependent EAE induction. Rag1-/- mice reconstituted with TCF-1-/- T cells were also susceptible to EAE, indicating TCF-1 is intrinsically required to repress IL-17. However, expression of wild-type TCF-1 or dominant negative TCF-1 did not interfere with Th17 differentiation in mature T cells. Furthermore, expression of TCF-1 in TCF-1-/- T cells could not restore Th17 differentiation to wild-type levels, indicating that TCF-1 cannot affect IL-17 production at the mature T cell stage. This is also supported by the normal up-regulation or activation in mature TCF-1-/- T cells of factors known to regulate Th17 differentiation, including RORγt and Stat3. We observed hyperacetylation together with trimethylation of Lys-4 at the IL-17 locus in TCF-1-/- thymocytes, two epigenetic modifications indicating an open active state of the gene. Such epigenetic modifications were preserved even when TCF-1-/- T cells migrated out of thymus. Therefore, TCF-1 mediates an active process to repress IL-17 gene expression via epigenetic modifications during T cell development. This TCF-1-mediated repression of IL-17 is critical for peripheral T cells to generate balanced immune responses
Calculation for Primary Combustion Characteristics of Boron-Based Fuel-Rich Propellant Based on BP Neural Network
A practical scheme for selecting characterization parameters of boron-based fuel-rich propellant formulation was put forward; a calculation model for primary combustion characteristics of boron-based fuel-rich propellant based on backpropagation neural network was established, validated, and then was used to predict primary combustion characteristics of boron-based fuel-rich propellant. The results show that the calculation error of burning rate is less than ±7.3%; in the formulation range (hydroxyl-terminated polybutadiene 28%–32%, ammonium perchlorate 30%–35%, magnalium alloy 4%–8%, catocene 0%–5%, and boron 30%), the variation of the calculation data is consistent with the experimental results
Calculation for Primary Combustion Characteristics of Boron-Based Fuel-Rich Propellant Based on BP Neural Network
A practical scheme for selecting characterization parameters of boron-based fuel-rich propellant formulation was put forward; a calculation model for primary combustion characteristics of boron-based fuel-rich propellant based on backpropagation neural network was established, validated, and then was used to predict primary combustion characteristics of boron-based fuel-rich propellant. The results show that the calculation error of burning rate is less than ±7.3%; in the formulation range (hydroxylterminated polybutadiene 28%-32%, ammonium perchlorate 30%-35%, magnalium alloy 4%-8%, catocene 0%-5%, and boron 30%), the variation of the calculation data is consistent with the experimental results
Uncoordinated Coupling Assessment of New Urbanization and Ecological Carrying Capacity in the Yellow River Basin
Under the restriction of the national “double carbon” goal, how to realize the coordination between urbanization and low-carbon development in the Yellow River Basin is a problem worthy of attention. In this paper, a new urbanization and ecological carrying capacity evaluation index system is established to evaluate the new urbanization level and ecological carrying capacity of the Yellow River Basin. On this basis, the uncoordinated coupling level of new urbanization and ecological carrying capacity in the Yellow River Basin is measured by using the improved uncoordinated coupling model, and its temporal and spatial characteristics and internal impact mechanism are analyzed. The study shows that the new urbanization and ecological carrying capacity of the Yellow River Basin has a benign development trend as a whole. Shandong province belongs to the low-level uncoordinated coupling type; Gansu Province and Qinghai Province belong to the running-in uncoordinated type; and Shanxi Province, the Inner Mongolia Autonomous Region, Shaanxi Province, and the Ningxia Hui Autonomous Region belong to the antagonistic uncoordinated coupling type. The uncoordinated coupling degree between new urbanization and ecological carrying capacity in the Yellow River Basin has a spatial interaction effect. It presents a low-level cluster centered on Shaanxi Province and Shandong Province and a high-level cluster centered on Gansu Province, Qinghai Province, and the Ningxia Hui Autonomous Region. From the perspective of the internal main impact mechanism, water resources have a two-way impact on the development of the two systems of new urbanization and ecological carrying capacity; the number of permanent residents and the level of scientific and technological investment have a one-way impact on the process of new urbanization; and the green coverage rate of built-up areas has a one-way impact on the development of ecological carrying capacity. The main contributions of this paper are as follows. First, the evaluation index system of new urbanization and ecological carrying capacity has been improved in combination with the new development concept. The evaluation of new urbanization by this index system is more in line with the current national requirements for high-quality development. Second, the impact of potential resources and human regulation has been added to the traditional ecological carrying capacity evaluation index system, and the evaluation of ecological carrying capacity by this index system is more in line with reality. Thirdly, taking the time effect into account, an improved uncoordinated coupling method is proposed. Using this method to evaluate the relationship between systems is conducive to bringing the dynamic relationship within the system into the evaluation system, which is more in line with the reality of system changes. Fourth, from the perspective of problem diagnosis, research on the relationship between new urbanization and ecological carrying capacity will help to find the internal mechanism that affects the coordinated development of new urbanization and ecological carrying capacity in the Yellow River Basin. This method is universal for exploring the internal influence mechanism of the relationship between systems
Raman scattering from In1-x-yGaxAlyAs quaternary alloys
The Raman scattering from In1-x-yGaxAly As/InP lattice matched quaternary alloys is studied. The alloys are grown on (100) oriented InP substrates by molecular beam epitaxy. The composition and intensity dependence of optical phonon mode frequencies show that the alloys exhibit three-mode behavior including InAs-like, GaAs-like and AlAs-like modes. The LO phonon modes are Raman active in the depolarized configuration and Raman inactive in the polarized configuration. TO phonon modes are also observed due to disorder effect, resulting in the asymmetrical shapes of the Raman peaks of phonons.link_to_subscribed_fulltex
Exploration of Catalytic Selectivity for Aminotransferase (BtrR) Based on Multiple Molecular Dynamics Simulations
The aminotransferase from Bacillus circulans (BtrR), which is involved in the biosynthesis of butirosin, catalyzes the pyridoxal phosphate (PLP)-dependent transamination reaction to convert valienone to β-valienamine (a new β-glycosidase inhibitor for the treatment of lysosomal storage diseases) with an optical purity enantiomeric excess value. To explore the stereoselective mechanism of valienamine generated by BtrR, multiple molecular dynamics (MD) simulations were performed for the BtrR/PLP/valienamine and BtrR/PLP/β-valienamine complexes. The theoretical results showed that β-valienamine could make BtrR more stable and dense than valienamine. β-valienamine could increase the hydrogen bond probability and decrease the binding free energy between coenzyme PLP and BtrR by regulating the protein structure of BtrR, which was conducive to the catalytic reaction. β-valienamine maintained the formation of cation-p interactions between basic and aromatic amino acids in BtrR, thus enhancing its stability and catalytic activity. In addition, CAVER 3.0 analysis revealed that β-valienamine could make the tunnel of BtrR wider and straight, which was propitious to the removal of products from BtrR. Steered MD simulation results showed that valienamine interacted with more residues in the tunnel during dissociation compared with β-valienamine, resulting in the need for a stronger force to be acquired from BtrR. Taken together, BtrR was more inclined to catalyze the substrates to form β-valienamine, either from the point of view of the catalytic reaction or product removal