Radiation proctitis (RP) is the most common complication of radiotherapy for pelvic tumor. Currently there is a lack of effective clinical treatment and its underlying mechanism is poorly understood. ...In this study, we aimed to dynamically reveal the mechanism of RP progression from the perspective of RNomics using a mouse model, so as to help develop reasonable therapeutic strategies for RP.
Mice were delivered a single dose of 25 Gy rectal irradiation, and the rectal tissues were removed at 4 h, 1 day, 3 days, 2 weeks and 8 weeks post-irradiation (PI) for both histopathological assessment and RNA-seq analysis. According to the histopathological characteristics, we divided the development process of our RP animal model into three stages: acute (4 h, 1 day and 3 days PI), subacute (2 weeks PI) and chronic (8 weeks PI), which could recapitulate the features of different stages of human RP. Bioinformatics analysis of the RNA-seq data showed that in the acute injury period after radiation, the altered genes were mainly enriched in DNA damage response, p53 signaling pathway and metabolic changes; while in the subacute and chronic stages of tissue reconstruction, genes involved in the biological processes of vessel development, extracellular matrix organization, inflammatory and immune responses were dysregulated. We further identified the hub genes in the most significant biological process at each time point using protein-protein interaction analysis and verified the differential expression of these genes by quantitative real-time-PCR analysis.
Our study reveals the molecular events sequentially occurred during the course of RP development and might provide molecular basis for designing drugs targeting different stages of RP development.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Abrasive single crystal diamond (SCD) is widely used in the machining process of sapphire. The wear characteristics of SCD grit have a significant influence on the tool wear and machining precision ...of sapphire. However, the influence of grit-workpiece contact form on the wear characteristics of SCD grit scratching on sapphire is not clear. In this paper, the wear characteristics of single SCD grit scratching on sapphire with three different grit-workpiece contact forms (point/line/face) are systematically investigated. Wear volume, wear morphology and scratching force are measured and tracked. Stress models of different contact forms are further established and analyzed. The results show that the SCD grit with face contact form can remove the most sapphire volume and it is the most wear-resistant. The SCD grit with point contact form can remove the fewest sapphire volume and it is the most prone to cleavage and fracture. Smaller stress results in more wear-resistant of the SCD grit during scratching on sapphire. Contact form is closely related to the stress state and has an important influence on the wear characteristics of SCD grit. The investigation results could provide a theoretical basis for the fabrication of abrasive tools.
Background
Chronic radiation proctitis (CRP), a common complication after radiotherapy for pelvic malignancies, compromises patient quality of life. Vascular damage and aberrant angiogenesis in the ...mucosal layer are essential histological features, but changes to the submucosal layer are unclear. Thus, we evaluated the histological characteristics and distribution changes of key angiogenic factors in full-layered human CRP samples.
Methods
Thirty paraffin-embedded CRP and twenty-nine non-CRP tissues were used to evaluate histopathological changes. Immunohistochemistry with anti-CD34 antibody was performed to calculate microvascular density (MVD). Frozen tissues from eight CRP patients and five non-CRP controls were collected and analyzed by antibody array, which contained sixty human angiogenesis-related factors. Quality controls with positive and negative controls were performed during antibody array analysis. Two differentially expressed factors were confirmed by ELISA.
Results
CRP lesions showed vasculopathy, fibrosis, mucosal ulceration, edema, and inflammatory cell infiltration. Human angiogenesis antibody array and ELISA confirmed the increased angiostatin in CRP lesions. Immunohistochemical staining showed dispersed distribution of angiostatin throughout the mucosal and submucosal layers in CRP lesions, while angiostatin accumulated within the vessel lumens in non-CRP tissues. MVD significantly decreased in the submucosal layer of CRP, suggesting a potential association with increased angiostatin.
Conclusions
Angiostatin increased and had a distinct distribution in CRP lesions. Compensatory telangiectasia in the mucosa, vessel stenosis, and reduced MVD might attenuate blood flow in the submucosa and contribute to CRP progression. Restoration of vascular functionality by promoting angiogenesis in the submucosal layer may help alleviate CRP in clinical practice.
Abrasive single crystal diamond (SCD) grit is widely used in the machining process of sapphire. The wear of SCD grit has a significant influence on the surface quality of sapphire. In this paper, ...smooth particle hydrodynamics (SPH) method is employed to reveal the wear mechanism of SCD grit with Steinberg constitutive equation and Grüneisen state equation. The wear morphology, wear volume and scratching forces are measured and analyzed by combination of SPH simulations and experiments. The results show that the scratching forces fluctuate in a certain range and decrease with the increasing of workpiece material removal volume. Different degrees of cleavage and fracture appear in the front and rear of SCD grit. The shear stress and extrusion stress are the main stresses of SCD grit during the scratching process. The wear progress and wear form are mainly determined by the stress state. Different stress state leads to different wear progress of the SCD grit. The SPH method is able to reflect and illustrate the wear characteristics of SCD grit scratching on sapphire.
Bivariate Hahn moments for image reconstruction Wu, Haiyong; Yan, Senlin
International Journal of Applied Mathematics and Computer Science,
06/2014, Letnik:
24, Številka:
2
Journal Article
Recenzirano
Odprti dostop
This paper presents a new set of bivariate discrete orthogonal moments which are based on bivariate Hahn polynomials with non-separable basis. The polynomials are scaled to ensure numerical ...stability. Their computational aspects are discussed in detail. The principle of parameter selection is established by analyzing several plots of polynomials with different kinds of parameters. Appropriate parameters of binary images and a grayscale image are obtained through experimental results. The performance of the proposed moments in describing images is investigated through several image reconstruction experiments, including noisy and noise-free conditions. Comparisons with existing discrete orthogonal moments are also presented. The experimental results show that the proposed moments outperform slightly separable Hahn moments for higher orders.
Generally, discrete orthogonal moments are difficult to induce rotation invariants. Based on relationship between Tchebichef polynomials and power series, we propose a new algorithm to compute ...rotation invariants of Tchebichef moments. The translation and scale invariants of Tchebichef moments are achieved by pre-normalizing the image to a standard image. Selected invariants of Tchebichef moments form a new effective shape feature for image retrieval. The retrieval performance of the proposed descriptor is compared with radial Tchebichef moment invariants and two kinds of Zernike moment invariants. Retrieval experiment results show that the proposed shape feature is robust to deformations generated by image shape rotation and scaling.
This paper conducts three-dimensional (3D), nonlinear finite element analyses (FEA) to predict ultimate load behavior of slab on steel stringer bridge superstructures. This is accomplished using the ...commercial finite element package ABAQUS to efficiently capture the behavior of such bridges; comprehensive details of the modeling procedure are presented herein. Two composite steel girders fabricated from high performance steel (HPS) and one four-span continuous composite steel bridge tested to failure have been used to validate the proposed FEA models. These FEA results indicate excellent agreement with the experimental data.
Diffusion MRI (DMRI) plays an essential role in diagnosing brain disorders related to white matter abnormalities. However, it suffers from heavy noise, which restricts its quantitative analysis. The ...total variance (TV) regularization is an effective noise reduction technique that penalizes noise-induced variances. However, existing TV-based denoising methods only focus on the spatial domain, overlooking that DMRI data lives in a combined spatioangular domain. It eventually results in an unsatisfactory noise reduction effect. To resolve this issue, we propose to remove the noise in DMRI using graph total variance (GTV) in the spatioangular domain. Expressly, we first represent the DMRI data using a graph, which encodes the geometric information of sampling points in the spatioangular domain. We then perform effective noise reduction using the powerful GTV regularization, which penalizes the noise-induced variances on the graph. GTV effectively resolves the limitation in existing methods, which only rely on spatial information for removing the noise. Extensive experiments on synthetic and real DMRI data demonstrate that GTV can remove the noise effectively and outperforms state-of-the-art methods.
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