68 research outputs found
Optimization of Ionic Liquid Based Simultaneous Ultrasonic- and Microwave-Assisted Extraction of Rutin and Quercetin from Leaves of Velvetleaf ( Abutilon theophrasti
An ionic liquids based simultaneous ultrasonic and microwave assisted extraction (ILs-UMAE) method has been proposed for the extraction of rutin (RU), quercetin (QU), from velvetleaf leaves. The influential parameters of the ILs-UMAE were optimized by the single factor and the central composite design (CCD) experiments. A 2.00 M 1-butyl-3-methylimidazolium bromide ([C4mim]Br) was used as the experimental ionic liquid, extraction temperature 60°C, extraction time 12 min, liquid-solid ratio 32 mL/g, microwave power of 534 W, and a fixed ultrasonic power of 50 W. Compared to conventional heating reflux extraction (HRE), the RU and QU extraction yields obtained by ILs-UMAE were, respectively, 5.49 mg/g and 0.27 mg/g, which increased, respectively, 2.01-fold and 2.34-fold with the recoveries that were in the range of 97.62–102.36% for RU and 97.33–102.21% for QU with RSDs lower than 3.2% under the optimized UMAE conditions. In addition, the shorter extraction time was used in ILs-UMAE, compared with HRE. Therefore, ILs-UMAE was a rapid and an efficient method for the extraction of RU and QU from the leaves of velvetleaf
Up-regulation of MiR-205 under hypoxia promotes epithelial-mesenchymal transition by targeting ASPP2
The epithelial–mesenchymal transition (EMT) is one of the crucial procedures for cancer invasion and distal metastasis. Despite undergoing intensive studies, the mechanisms underlying EMT remain to be completely elucidated. Here, we identified that apoptosis-stimulating protein of p53-2 (ASPP2) is a novel target of MiR-205 in various cancers. Interestingly, the binding site of MiR-205 at the 3′-untranslated region of ASPP2 was highly conserved among different species. An inverse correlation between MiR-205 and ASPP2 was further observed in vivo in cervical cancers, suggesting MiR-205 may be an important physiological inhibitor of ASPP2. Hypoxia is a hallmark of solid tumor microenvironment and one of such conditions to induce EMT. Notably, MiR-205 was remarkably induced by hypoxia in cervical and lung cancer cells. A marked suppression of ASPP2 was observed simultaneously. Further studies confirmed that hypoxia-induced ASPP2 suppression was mainly attributed to the elevated MiR-205. Interestingly, the alteration of MiR-205/ASPP2 under hypoxia was accompanied with the decreased epithelial marker E-cadherin and increased mesenchymal marker Vimentin, as well as a morphological transition from the typical cobblestone-like appearance to the mesenchymal-like structure. More importantly, MiR-205 mimics or ASPP2 silencing similarly promoted EMT process. By contrast, ASPP2 recovery or MiR-205 inhibitor reversed MiR-205-dependent EMT. Further studies demonstrated that the newly revealed MiR-205/ASPP2 axis promoted cell migration and also increased cell proliferation both in vivo and in vitro. These data together implicated a critical impact of MiR-205/ASPP2 on promoting EMT. MiR-205/ASPP2 may be potential diagnostic and therapeutic biomarkers in cervical and lung cancers
Leadership, management, quality, and innovation in organ donation: 2019 Kunming recommendations for One Belt & One Road countries
The findings and recommendations of the 2019 consensus conference in organ donation, held in Kunming, China, are here reported. The main objective of the conference was to gather relevant information from experts involved in the field. The data and opinions provided allowed to propose a series of recommendations for 'One Belt & One Road Countries' on how to achieve self-sufficiency in organ donation. Leadership in organ donation should be results-oriented and goal-driven based on the principles of excellence, empowerment, and engagement, providing the means, resources, and strategies necessary to reach the goal in earnest. Management includes good governance and transparency of a national registry of patients in the waiting list, donors, transplants, transplant teams, quality, and safety programs with continuous educational training of health care professionals. Mandatory monitoring, auditing and evaluation of quality must be incorporated into donation practices as relevant points in innovation, as well as the adoption of already established and novel processes and technologies. Achievement of self-sufficiency in organ donation is a crucial step to fight against transplant tourism and to prevent organ trafficking. Based on recommendations arising from the conference, each country could review and develop individualized action plans adjusted to its own circumstances and reality
A temporally cyclic growth model of urban spatial morphology in China: evidence from Kunming Metropolis
Rapid urbanization and complexity of political-economic transition in China has brought about continuous and remarkable changes of urban morphology over the past decades, which were driven by a mixture of spatial, social-economic and institutional forces. Understanding such urban morphological evolution requires new mixed evidences and holistic perspectives. In this paper, it is argued that two dominant types of urban growth in China: low-density expansion and high-density infill might be driven by different forces at different stages. To interpret the processes of urban development, two easy-to-understand morphological indicators: expansion-induced investment density index” (EID) and “infill-induced investment density index” (IID) are defined to measure the investment density per unit of developed land and used to compare the morphological changes between different phases in a long period by integrating spatial and socio-economic data. The temporal variation of these indicators suggests a cyclic growth model (CGM), which means the periodic switch between low density expansion and high-density infill. Using Kunming metropolis as a case study, this paper has confirmed that its urban morphological evolution from 1950-2014 was periodically and reciprocally driven by a set of vis-à -vis dualistic dynamics, in which low-density expansion is led by pro-growth infrastructure oriented public investment, while the high-density infill is activated by collective and rational actions of individual enterprises and their economic behaviors. It is concluded that the confirmed CGM model, together with two morphological indicators, offers a new holistic perspective and method to easily and integrally interpret urban morphological evolution and accordingly has potential theoretical implications for reasonably understanding the urbanisation in China
lncRNA HITT Inhibits Lactate Production by Repressing PKM2 Oligomerization to Reduce Tumor Growth and Macrophage Polarization
Lactic acid acidifies the tumor microenvironment and promotes multiple critical oncogenic processes, including immune evasion. Pyruvate kinase M2 (PKM2) is a dominant form of pyruvate kinase (PK) expressed in cancers that plays essential roles in metabolic reprograming and lactate production, rendering it as an attractive therapeutic target of cancer. However, the mechanism underlying PKM2 regulation remains unclear. Here, we show that long noncoding RNA (lncRNA) HIF-1α inhibitor at transcription level (HITT) inhibits lactate production in a PKM2-dependent manner. Mechanistically, it physically interacts with PKM2 mapped to a region that has been involved in both dimer (less-active) and tetramer (more-active) formation, inhibiting PKM2 oligomerization and leading to dramatic reduction of PK activity. Under glucose starvation, HITT was reduced as a result of miR-106 induction, which subsequently facilitates PKM2 oligomerization and increases vulnerability to apoptosis under glucose starvation stress. In addition, the interaction also reduces lactate secretion from cancer cells, which subsequently polarizes macrophages toward an M2-like anti-inflammatory phenotype and thus possibly contributes to immune escape in vivo. This study highlights an important role of an lncRNA in regulating PKM2 activity and also reveals a metabolic regulatory effect of PKM2 on macrophage polarization
A long noncoding RNA sensitizes genotoxic treatment by attenuating ATM activation and homologous recombination repair in cancers.
Ataxia-telangiectasia mutated (ATM) is an apical kinase of the DNA damage response following DNA double-strand breaks (DSBs); however, the mechanisms of ATM activation are not completely understood. Long noncoding RNAs (lncRNAs) are a class of regulatory molecules whose significant roles in DNA damage response have started to emerge. However, how lncRNA regulates ATM activity remains unknown. Here, we identify an inhibitor of ATM activation, lncRNA HITT (HIF-1α inhibitor at translation level). Mechanistically, HITT directly interacts with ATM at the HEAT repeat domain, blocking MRE11-RAD50-NBS1 complex-dependent ATM recruitment, leading to restrained homologous recombination repair and enhanced chemosensitization. Following DSBs, HITT is elevated mainly by the activation of Early Growth Response 1 (EGR1), resulting in retarded and restricted ATM activation. A reverse association between HITT and ATM activity was also detected in human colon cancer tissues. Furthermore, HITTs sensitize DNA damaging agent-induced cell death both in vitro and in vivo. These findings connect lncRNA directly to ATM activity regulation and reveal potential roles for HITT in sensitizing cancers to genotoxic treatment
Top coal drawing law for an extra thick coal seam under the single round group drawing method
Abstract To solve the problems of poor top coal drawing, lagging collapse, and difficulty in parallel operation of mining and drawing in extra-thick coal seams, considering the 8222 working face of the Tashan Mine as the engineering background, we first investigate the basic problems of fully mechanized top coal drawing mining in extra-thick coal seams using the single-round group drawing method (GDM). We then analyze the drawing law of top coal with different thicknesses under the single-round GDM from the aspects of top coal recovery (TCR) and drawing efficiency, coal loss mechanism, and the relation between TCR and gangue content (GC), providing a basis for determining the process parameters of GDM. Results indicate that as the top coal thickness increases, the number of drawing openings considerably influences drawing efficiency and top coal loss. And there is a notable thickness effect of the number of drawing openings on the top coal loss. There is a quantitative relationship among TCR, cumulative GC (CGC) and instantaneous GC (IGC), and CGC and TCR can be predicted based on the IGC. Consequently, theoretical analysis and numerical simulation results indicate that the optimal IGC threshold at the coal drawing openings between 31.2 and 40%. Through optimizing the coal drawing method and strictly controlling the IGC at the coal drawing openings on-site, the measured working face TCR increased from 75.25 to 90.12%, and CGC was controlled at approximately 9%. Meanwhile, the average coordination efficiency of mining and drawing time reaches 68.2%, effectively ensuring the construction of a coal mine with an annual output of 15 million tons
Research on the Performance of an Active Rotating Tropospheric and Stratospheric Doppler Wind Lidar Transmitter and Receiver
This paper investigates the transmitter and receiver performance of an active rotating tropospheric stratospheric Doppler wind Lidar. A 532 nm laser was determined as the detection wavelength based on transmission and scattering aspects. A ten-fold Galileo beam expander consisting of spherical and aspherical mirrors was designed and produced to compress the outgoing laser’s divergence angle using ZEMAX simulation optimization and optical-mechanical mounting means. The structure and support of the 800 mm Cassegrain telescope was redesigned. Additionally, the structure of the receiver was optimized, and the size was reduced. Meanwhile, the detectors and fiber mountings were changed to improve the stability of the received optical path. A single-channel atmospheric echo signal test was used to select the best-performing photomultiplier tube (PMT). Finally, the atmospheric wind field detection results of the original and upgraded systems were compared. The results show that after optimizing the transmitter and receiver, the detection altitude of the system is increased to about 47 km, and the wind speed and wind direction profiles match better with radiosonde measurements
Optical–Mechanical Integration Analysis and Validation of LiDAR Integrated Systems with a Small Field of View and High Repetition Frequency
Integrated systems are facing complex and changing environments with the wide application of atmospheric LiDAR in civil, aerospace, and military fields. Traditional analysis methods employ optical software to evaluate the optical performance of integrated systems, and cannot comprehensively consider the influence of optical and mechanical coupling on the optical performance of the integrated system, resulting in the unsatisfactory accuracy of the analysis results. Optical–mechanical integration technology provides a promising solution to this problem. A small-field-of-view LiDAR system with high repetition frequency, low energy, and single-photon detection technology was taken as an example in this study, and the Zernike polynomial fitting algorithm was programmed to enable transmission between optical and mechanical data. Optical–mechanical integration technology was employed to obtain the optical parameters of the integrated system under a gravity load in the process of designing the optical–mechanical structure of the integrated system. The experimental validation results revealed that the optical–mechanical integration analysis of the divergence angle of the transmission unit resulted in an error of 2.586%. The focal length of the telescope increased by 89 μm, its field of view was 244 μrad, and the error of the detector target surface spot was 4.196%. The continuous day/night detection results showed that the system could accurately detect the temporal and spatial variations in clouds and aerosols. The inverted optical depths were experimentally compared with those obtained using a solar photometer. The average optical depth was 0.314, as detected using LiDAR, and 0.329, as detected by the sun photometer, with an average detection error of 4.559%. Therefore, optical–mechanical integration analysis can effectively improve the stability of the structure of highly integrated and complex optical systems
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