Hypoxia-inducible factor 1-α (HIF-1α) plays a critical role in angiogenesis-osteogenesis coupling during bone development and bone regeneration. Previous studies have shown that 17β-estradiol ...activates the HIF-1α signaling pathway and that mice with conditional activation of the HIF-1α signaling pathway in osteoblasts are protected from ovariectomy (OVX)-induced bone loss. In addition, it has been shown that hypoxia facilitates the osteogenic differentiation of mesenchymal stem cells (MSCs) and modulates Wnt/β-catenin signaling. Therefore, we hypothesized that activation of the HIF-1α signaling pathway by hypoxia-mimicking agents would prevent bone loss due to estrogen deficiency. In this study, we confirmed the effect of dimethyloxalylglycine (DMOG), a hypoxia-mimicking agent, on the HIF-1α signaling pathway and investigated the effect of DMOG on MSC osteogenic differentiation and the Wnt/β-catenin signaling pathway. We then investigated the effect of DMOG treatment on OVX-induced bone loss. Female C57BL/6J mice were divided into sham, OVX, OVX+L-DMOG (5 mg/kg/day), and OVX+H-DMOG (20 mg/kg/day) groups. At sacrifice, static and dynamic bone histomorphometry were performed with micro computed tomography (micro-CT) and undecalcified sections, respectively. Bone strength was assessed with the three-point bending test, and femur vessels were reconstructed and analyzed by micro-CT. Serum vascular endothelial growth factor (VEGF), osteocalcin, and C-terminal telopeptides of collagen type(CTX) were measured by ELISA. Tartrate-resistant acid phosphatase staining was used to assess osteoclast formation. Alterations in the HIF-1α and Wnt/β-catenin signaling pathways in the bone were detected by western blot. Our results showed that DMOG activated the HIF-1α signaling pathway, which further activated the Wnt/β-catenin signaling pathway and enhanced MSC osteogenic differentiation. The micro-CT results showed that DMOG treatment improved trabecular bone density and restored the bone microarchitecture and blood vessels in OVX mice. Bone strength was also partly restored in DMOG-treated OVX mice. Dynamic bone histomorphometric analysis of the femur metaphysic revealed that DMOG increased the mineralizing surface, mineral apposition rate, and bone formation rate. The serum levels of VEGF and osteocalcin were higher in DMOG-treated OVX mice. However, there were no significant differences in serum CTX or in the number of tartrate-resistant acid phosphatase-stained cells between DMOG-treated OVX mice and OVX mice. Western blot results showed that DMOG administration partly rescued the decrease in HIF-1α and β-catenin expression following ovariectomy. Collectively, these results indicate that DMOG prevents bone loss due to ovariectomy in C57BL/6J mice by enhancing angiogenesis and osteogenesis, which are associated with activated HIF-1α and Wnt/β-catenin signaling pathways.
The emerging recognition of the functional roles of circular RNAs (circRNAs) has given rise to a new perspective regarding our understanding of cellular physiology and disease pathogenesis. Unlike ...linear RNAs, circRNAs are covalently closed continuous loops that act as gene regulators in mammals, and their sequence composition determines the mode of circRNA biogenesis. The availability and integrated use of advanced genome analysis platforms have allowed the identification of a large number of these molecules. Their high abundance, stability and evolutionary conservation among species endow circRNAs with numerous potential functions, such as acting as microRNA (miRNA) sponges or binding to RNA-associated proteins to form RNA-protein complexes that regulate gene transcription. Moreover, circRNAs have been shown to be expressed in a tissue-specific manner and in pathological conditions, which has stimulated significant interest in their role in human disease and cancer. In this concise review, we outline the characteristics, functions and mechanisms of action of circRNAs as well as their involvement in different diseases. Although their exact roles and mechanisms of gene regulation remain to be clarified, circRNAs have potential applications as disease biomarkers and novel therapeutic targets.
The navy and other Department of Defense organizations are increasingly interested in the use of unmanned surface vehicles （USVs） for a variety of missions and applications. The term USV refers to ...any vehicle that operates on the surface of the water without a crew. USVs have the potential, and in some cases the demonstrated ability, to reduce risk to manned forces, provide the necessary force multiplication to accomplish military missions, perform tasks which manned vehicles cannot, and do so in a way that is affordable for the navy. A survey of USV activities worldwide as well as the general technical challenges of USVs was presented below. A general description of USVs was provided along with their typical applications. The technical challenges of developing a USV include its intelligence level, control, high stability, and developmental cost reduction. Through the joint efforts of researchers around the world, it is believed that the development of USVs will enter a new phase in the near future, as USVs could soon be applied widely both in military and civilian service.
•Granular activated carbon was modified by polydimethylsiloxane (PDMS).•Pore structure and surface chemistry of bare and modified AC were characterized.•PDMS coated AC had better benzene adsorption ...capacity under humid conditions.•Hydrophobic PDMS-coated surface favors benzene adsorption under humid conditions.
A series of hydrophobic-modified (polydimethylsiloxane (PDMS) coating) activated carbons (ACs) were developed to answer a fundamental question: what are the determinants that dominate the adsorption on ACs under humid conditions? Using column experiments, an inter-comparison among bare-AC and PDMS-coated ACs was conducted regarding the association of surface characteristics and adsorption capacity. Primary outcomes occurred in two dominating markers, hydrophobicity and total micropore volume, which played a key role in water adsorption on ACs. However, their contributions to water adsorption on ACs substantially differed under different Pwater/Pair conditions. Hydrophobicity was the only contributor in Pwater/Pair=0.1–0.6, while the two markers contributed equally in Pwater/Pair=0.7–1.0. Furthermore, PDMS-coated AC had a significant increase in benzene adsorption capacities compared to bare-AC at 0–90% relative humidity, while these differences were not significant among PDMS-coated ACs. It is thus presumed that the balance between the two markers can be shifted to favor almost unchanged benzene adsorption capacities among PDMS-coated ACs over a large range of relative humidity. These findings suggest potential benefits of PDMS coating onto ACs in enhancing selective adsorption of hydrophobic volatile organic compounds under high humid conditions. To develop new porous materials with both high total micropore volume and hydrophobicity should thus be considered.
Environmental technology innovation is a crucial measure of the quality of China’s economic development and sustainable environmental protection. Based on the 2009–2017 provincial panel data from ...China, this article used the modified projection pursuit model to measure the environmental technology innovation capabilities of various regions. Moreover, this article empirically investigates the threshold effect of outward foreign direct investment on China’s environmental technology innovation under different intellectual property protection levels. The results are as follows. First, the environmental technology innovation capabilities of China’s regions vary significantly, showing an “east-middle-west” gradient decline trend similar to levels of economic development. Second, outward foreign direct investment has a significant reverse environmental technology innovation effect, but this effect has complex nonlinear characteristics. Third, in the process of outward foreign direct investment affecting environmental technology innovation, intellectual property protection has a significant double threshold effect. As the level of intellectual property protection continues to cross the threshold value, the effect direction of outward foreign direct investment on environmental technology innovation undergoes a sudden change from inhibition to promotion. However, when intellectual property protection is too high, the promotion effect is relatively limited. This paper provides some reference points and insights that should aid in establishing a scientific intellectual property protection system and raising the level of environmental technology innovation.
Chiral colloidal semiconductor nanocrystals (NCs) are an emerging type of chiral materials. These chiral NCs exhibit unique quantum confinement-determined optical activity and have aroused much ...interest in the multidisciplinary fields of chemistry, physics and biology. Herein, the state-of-the-art progresses of their rational synthesis, fundamental understanding and potential application are summarized. In addition, a personal view about the future development of chiral semiconductor NCs is offered.
In this paper, for the common behaviors of students in classroom teaching, deep learning and the improved student behavior detection algorithm based on YOLOv5s are used to transform the source data ...into another high-level and high-abstract data expression to realize the detection of students’ behavior in class. Then, taking into account the real conditions of college students and the internal logic of deep learning and classroom teaching, we sort out the target conditions of college students’ deep learning and their brand-new requirements for college classroom teaching and innovate the art teaching mode in colleges and universities. The innovative art teaching mode is applied in the art classroom teaching of W College of Fine Arts, and the teaching effect is analyzed. The results show that the mean values of students’ evaluation in the five core literacy skills of image literacy, art expression, aesthetic judgment, creative practice, and cultural understanding increased by 12.6, 14.95, 17.66, 12.27, and 19.1 points after the innovation compared with those before the innovation. The above data show that the innovation of art teaching mode can enhance students’ motivation to learn and stimulate their creative passion, thus cultivating their creative ability, making students learn to inherit and carry forward the traditional culture of the Chinese nation, and enhancing their cultural self-confidence and national pride.
The unique capability of magnetic circular dichroism (MCD) in revealing geometry and electronic information has provided new opportunities in exploring the relationship between structure and ...magneto‐optical properties in nanomaterials with extraordinary optical absorption. Here, the representative studies referring to application of the MCD technique in semiconductor and noble metal nanomaterials are overviewed. MCD is powerful in elucidating the structural information of the excitonic transition in semiconductor nanocrystals, electronic transitions in noble metal nanoclusters, and plasmon resonance in noble metal nanostructures. By virtue of these advantages, the MCD technique shows its unrivalled ability in evaluating the magnetic modulation of excitonic and plasmonic optical activity of nanomaterials with varied chemical composition, geometry, assembly conformation, and coupling effect. Knowledge of the key factors in manipulating magneto‐optical properties at the nanoscale acquired with the MCD technique will largely boost the application of semiconductor and noble nanomaterials in the fields of sensing, spintronic, nanophotonics, etc.
Magnetic circular dichroism shows indispensable capability in elucidating the Zeeman splitting of the excitonic transition in semiconductor nanocrystals, the electronic information of discrete optical transitions in noble metal nanoclusters, and the geometry modulation of plasmon resonance in noble metal nanostructures. Key strategies in designing magneto‐optically active advanced nanomaterials are highlighted for potential applications in fields of sensing, spintronics, and nanophotonics.
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