45 research outputs found
Cooperation between NRF2-mediated transcription and MDIG-dependent epigenetic modifications in arsenic-induced carcinogenesis and cancer stem cells
Environmental exposure to arsenic, a well-established carcinogen linked to a number of human cancers, is a public health concern in many areas of the world. Despite extensive studies on the molecular mechanisms of arsenic-induced carcinogenesis, how initial cellular responses, such as activation of stress kinases and the generation of reactive oxygen species, converge to affect the transcriptional and/or epigenetic reprogramming required for the malignant transformation of normal cells or normal stem cells remains to be elucidated. In this review, we discuss some recent discoveries showing how the transcription factor NRF2 and an epigenetic regulator, MDIG, contribute to the arsenic-induced generation of cancer stem-like cells (CSCs) as determined by applying CRISPR-Cas9 gene editing and chromosome immunoprecipitation followed by DNA sequencing (ChIP-seq)
Fabricating a novel HLC-hBMP2 fusion protein for the treatment of bone defects
Treating serious bone trauma with an osteo-inductive agent such as bone morphogenetic proteins (BMPs) has been considered as an optimized option when delivered via a collagen sponge (CS). Previous work has shown that the BMP concentration and release rate from approved CS carriers is difficult to control with precision. Here we presented the fabrication of a recombinant fusion protein from recombinant human-like collagen (HLC) and human BMP-2 (hBMP2). The fusion protein preserved the characteristic of HLC allowing the recombinant protein to be expressed in Yeast (such as Pichia pastoris GS115) and purified rapidly and easily with mass production after methanol induction. It also kept the stable properties of HLC and hBMP2 in the body fluid environment with good biocompatibility and no cytotoxicity. Moreover, the recombinant fusion protein fabricated a vertical through-hole structure with improved mechanical properties, and thus facilitated migration of bone marrow mesenchymal stem cells (MSCs) into the fusion materials. Furthermore, the fusion protein degraded and released hBMP-2 in vivo allowing osteoinductive activity and the enhancement of utilization rate and the precise control of the hBMP2 release. This fusion protein when applied to cranial defects in rats was osteoinductively active and improved bone repairing enhancing the repairing rate 3.5- fold and 4.2- fold when compared to the HLC alone and the control, respectively. There were no visible inflammatory reactions, infections or extrusions around the implantation sites observed. Our data strongly suggests that this novel recombinant fusion protein could be more beneficial in the treatment of bone defects than the simple superposition of the hBMP2/collagen sponge
Exploring the potential of the recombinant human collagens for biomedical and clinical: a short review
Natural animal collagen and its recombinant collagen are favorable replacements in human tissue engineering due to their remarkable biomedical property. However, this exploitation is largely restricted due to the potential of immunogenicity and virus contamination. Exploring new ways to produce human collagen is a fundamental key to its biomedical and clinical application. All human fibrillar collagen molecules have three polypeptide chains constructed from a repeating Gly-Xaa-Yaa triplet, where Xaa and Yaa represent one random amino acid. Using cDNA techniques to modify several repeat sequences of the cDNA fragment, a novel human collagen named recombinant human-like collagen (HLC), with low immunogenicity and little risk from hidden virus can be engineered and notably tailored to speciļ¬c applications. HLC was initially used as a coating to modify the tissue engineering scaffold, and then used as the scaffold after cross link agents were added to increase its mechanical strength. Due to its good biocompatibility, low immunogenicity, stabilised property and the ability of mass production, HLC has been widely considered to use in skin injury treatments, vascular scaffolds engineering, cartilage, bone defect repair, skincare, haemostatic sponge, and drug delivery including coating with medical nanoparticles. In this review, we symmetrically reviewed the development, recent advances in design and application of HLC, and other recombinant human collagen-based biomedicine potentials. For comparison and providing basic background information about the techniques, we start with recombinant human collagens. In the end, future improvements in using HLC are also discussed
Sex-specific participation in inter-group conflicts within a multilevel society: the first evidence at the individual level
Inter-group conflicts are common among many group-living animals and involve potentially complex motivations
and interactions. Mammals living in multilevel societies offer a good opportunity to study inter-group
conflicts. This study is the first to explore the function of sex-specific participation during inter-group conflicts
within a multilevel society at the individual level. The Sichuan snub-nosed monkey (Rhinopithecus roxellana)
is an endangered seasonal breeding species living in a multilevel society. From Sep 2007 to May 2008 we recorded
290 inter-group conflicts of a free-ranging provisioned band of R. roxellana in the Qinling Mountains of
China to investigate the function of individual aggression during inter-group encounters. Our findings show that
adult males were the main participants in inter-group conflicts, while females took part in them only occasionally.
The male participation rate during the mating season, when adult females were estrous, was significantly
higher than that during the non-mating season. Furthermore, males directed their aggression to other males, and
directed more intense aggression towards bachelor males than towards other resident males. For both sexes, the
participation rate as initiators was higher in the winter than that in the spring; and there was a significant positive
correlation between group size and the participation rate as initiators. Our results suggest that inter-group
aggression in Sichuan snub-nosed monkeys is linked to both mate defense and resource defens
Improved Intra-Pixel Sensitivity Characterization Based on Diffusion and Coupling Model for Infrared Focal Plane Array Photodetector
The high-precision characterization of the intra-pixel sensitivity (IPS) for infrared focal plane array (FPA) photodetector is of great significance to high-precision photometry and astrometry in astronomy, as well as target tracking in under-sampled remote sensing images. The discrete sub-pixel response (DSPR) model and fill factor model have been used for IPS characterization in some studies. However, these models are incomplete and lack the description of physical process of charge diffusion and capacitance coupling, leading to the inaccuracy of IPS characterization. In this paper, we propose an improved IPS characterization method based on the diffusion and coupling physical (DCP) model for infrared FPA photodetector, which considering the processes of generation and collection of the charge, can improve the accuracy of IPS characterization. The IPS model can be obtained by convolving the ideal rectangular response function with the charge diffusion function and the capacitive coupling function. Then, the IPS model is convolved with the beam spot profile to obtain the beam spot scanning response model. Finally, we calculate the parameters of IPS by fitting the beam spot scanning response map with the proposed DCP model based on the Trust-Region-Reflective algorithm. Simulated results show that when using a 3 Ī¼m beam spot to scan, the error of IPS characterization based on DCP model is 0.63%, which is better than that of DSPR modelās 3.70%. Experimental results show that the fitting error of the beam spot scan response model based on DCP model is 4.29%, which is better than that of DSPR modelās 8.31%
SDGSAT-1 TIS Prelaunch Radiometric Calibration and Performance
SDGSAT-1 was launched in November 2021, and TIS (Thermal infrared sensor) is a major instrument onboard this satellite. An analysis of the radiometric calibration and noise performance of the TIS has been carried out in the thermal vacuum chamber before launch in order to ensure that it meets the requirements. The prelaunch test results show NEdT (noise equivalent temperature difference) is 0.034 K, 0.047 K and 0.076 K@300 K for the three bands, respectively. The maximum fitting residuals are less than 0.5 K at measured blackbody temperatures. In addition, this paper also discusses the dependence between TIS performance and instrument temperature and focal plane array (FPA) temperature. The good radiometric and noise performance of TIS demonstrates it has potential to provide high resolution thermal remote sensing data in urban heat island, and other environmental issues research
Multi-Sensor Fusion of SDGSAT-1 Thermal Infrared and Multispectral Images
Thermal infrared imagery plays an important role in a variety of fields, such as surface temperature inversion and urban heat island effect analysis, but the spatial resolution has severely restricted the potential for further applications. Data fusion is defined as data combination using multiple sensors, and fused information often has better results than when the sensors are used alone. Since multi-resolution analysis is considered an effective method of image fusion, we propose an MTF-GLP-TAM model to combine thermal infrared (30 m) and multispectral (10 m) information of SDGSAT-1. Firstly, the most relevant multispectral bands to the thermal infrared bands are found. Secondly, to obtain better performance, the high-resolution multispectral bands are histogram-matched with each thermal infrared band. Finally, the spatial details of the multispectral bands are injected into the thermal infrared bands with an MTF Gaussian filter and an additive injection model. Despite the lack of spectral overlap between thermal infrared and multispectral bands, the fused image improves the spatial resolution while maintaining the thermal infrared spectral properties as shown by subjective and objective experimental analyses