31 research outputs found

    Quasi-Brittle Fracture Modeling of Preflawed Bitumen Using a Diffuse Interface Model

    Get PDF
    Fundamental understandings on the bitumen fracture mechanism are vital to improve the mixture design of asphalt concrete. In this paper, a diffuse interface model, namely, phase-field method is used for modeling the quasi-brittle fracture in bitumen. This method describes the microstructure using a phase-field variable which assumes one in the intact solid and negative one in the crack region. Only the elastic energy will directly contribute to cracking. To account for the growth of cracks, a nonconserved Allen-Cahn equation is adopted to evolve the phase-field variable. Numerical simulations of fracture are performed in bituminous materials with the consideration of quasi-brittle properties. It is found that the simulation results agree well with classic fracture mechanics

    Fractal Analysis on Asphalt Mixture Using a Two-Dimensional Imaging Technique

    Get PDF
    Fractal is a mathematical set that has a fractal dimension which usually exceeds its topological dimension and may be nonintegral. Since the asphalt pavement texture has limitations of randomness and self-similarity, fractal theory has been explored to quantify the asphalt pavement texture and employs good applicability in processing and analyzing the complex details of research object. In this paper, the 2D digital image of the pavement surface is measured in terms of area fractal dimension and contour fractal dimension, which are used to correlate with aggregate gradation and British Pendulum Number (BPN) value, respectively. It turns out the area fractal dimension of aggregate provides a simple way to acquire the continuous gradation of asphalt concrete sample and the contour fractal dimension is an available parameter to characterize roughness and friction of pavement surface texture

    miR-200 Enhances Mouse Breast Cancer Cell Colonization to Form Distant Metastases

    Get PDF
    BACKGROUND: The development of metastases involves the dissociation of cells from the primary tumor to penetrate the basement membrane, invade and then exit the vasculature to seed, and colonize distant tissues. The last step, establishment of macroscopic tumors at distant sites, is the least well understood. Four isogenic mouse breast cancer cell lines (67NR, 168FARN, 4TO7, and 4T1) that differ in their ability to metastasize when implanted into the mammary fat pad are used to model the steps of metastasis. Only 4T1 forms macroscopic lung and liver metastases. Because some miRNAs are dysregulated in cancer and affect cellular transformation, tumor formation, and metastasis, we examined whether changes in miRNA expression might explain the differences in metastasis of these cells. METHODOLOGY/PRINCIPAL FINDINGS: miRNA expression was analyzed by miRNA microarray and quantitative RT-PCR in isogenic mouse breast cancer cells with distinct metastatic capabilities. 4T1 cells that form macroscopic metastases had elevated expression of miR-200 family miRNAs compared to related cells that invade distant tissues, but are unable to colonize. Moreover, over-expressing miR-200 in 4TO7 cells enabled them to metastasize to lung and liver. These findings are surprising since the miR-200 family was previously shown to promote epithelial characteristics by inhibiting the transcriptional repressor Zeb2 and thereby enhancing E-cadherin expression. We confirmed these findings in these cells. The most metastatic 4T1 cells acquired epithelial properties (high expression of E-cadherin and cytokeratin-18) compared to the less metastatic cells. CONCLUSIONS/SIGNIFICANCE: Expression of miR-200, which promotes a mesenchymal to epithelial cell transition (MET) by inhibiting Zeb2 expression, unexpectedly enhances macroscopic metastases in mouse breast cancer cell lines. These results suggest that for some tumors, tumor colonization at metastatic sites might be enhanced by MET. Therefore the epithelial nature of a tumor does not predict metastatic outcome

    Transcriptome Profiling to Identify Genes Involved in Non-Target-Site-Based Resistance to Clodinafop-Propargyl in Asia Minor Bluegrass (<i>Polypogon fugax</i>)

    No full text
    Asia Minor bluegrass (Polypogon fugax Nees ex Steud.) is a problematic grass weed of winter crops in China, where some populations have become resistant to herbicides. Previously, we identified a P. fugax population QS exhibiting target-site-based resistance (TSR) and non-target-site-based resistance (NTSR) to clodinafop-propargyl. This study aims to understand the metabolic resistance to clodinafop-propargyl between susceptible (XC) and resistant (QS) populations of P. fugax in the seedling and tillering stage, separately. Several differentially expressed candidate genes in the seedling and tillering stages were identified by RNA-Seq, including three P450 family genes, one glutathione S-transferase (GST) gene, and two ATP-binding cassette transporters. Additionally, we discovered a GST gene that was significantly differentially expressed in the resistant population during the seedling stage, as well as three peroxidase genes that were presumed to be related to NTSR metabolism. Three other peroxidase genes and one esterase were presumed to be related to NTSR metabolism during the tillering stage of the resistant population. Overexpression of the three randomly selected candidate genes can enhance herbicide-resistance in Arabidopsis transgenic plants. This study provided a novel insight into herbicide metabolism regulation genes during the different growth stages of resistant P. fugax population

    Adrenarche-accompanied rise of adrenal sex steroid precursors prevents NAFLD in Young Female rats by converting into active androgens and inactivating hepatic Srebf1 signaling

    No full text
    Abstract Background Non-alcoholic fatty liver disease (NAFLD) has rapidly become the most common cause of chronic liver disease in children and adolescents, but its etiology remains largely unknown. Adrenarche is a critical phase for hormonal changes, and any disturbance during this period has been linked to metabolic disorders, including obesity and dyslipidemia. However, whether there is a causal linkage between adrenarche disturbance and the increasing prevalence of NAFLD in children remains unclear. Results Using the young female rat as a model, we found that the liver undergoes a transient slowdown period of growth along with the rise of adrenal-derived sex steroid precursors during adrenarche. Specifically blocking androgen actions across adrenarche phase using androgen receptor antagonist flutamide largely increased liver weight by 47.97% and caused marked fat deposition in liver, thus leading to severe NAFLD in young female rats. Conversely, further administrating nonaromatic dihydrotestosterone (DHT) into young female rats across adrenarche phase could effectively reduce liver fat deposition. But, administration of the aromatase inhibitor, formestane across adrenarche had minimal effects on hepatic de novo fatty acid synthesis and liver fat deposition, suggesting adrenal-derived sex steroid precursors exert their anti-NAFLD effects in young females by converting into active androgens rather than into active estrogens. Mechanistically, transcriptomic profiling and integrated data analysis revealed that active androgens converted from the adrenal sex steroid precursors prevent NAFLD in young females primarily by inactivating hepatic sterol regulatory element-binding transcription factor 1 (Srebf1) signaling. Conclusions We firstly evidenced that adrenarche-accompanied rise of sex steroid precursors plays a predominant role in preventing the incidence of NAFLD in young females by converting into active androgens and inactivating hepatic Srebf1 signaling. Our novel finding provides new insights into the etiology of NAFLD and is crucial in developing effective prevention and management strategies for NAFLD in children

    Exogenous Hemin enhances the antioxidant defense system of rice by regulating the AsA-GSH cycle under NaCl stress

    No full text
    Abiotic stress caused by soil salinization remains a major global challenge that threatens and severely impacts crop growth, causing yield reduction worldwide. In this study, we aim to investigate the damage of salt stress on the leaf physiology of two varieties of rice (Huanghuazhan, HHZ, and Xiangliangyou900, XLY900) and the regulatory mechanism of Hemin to maintain seedling growth under the imposed stress. Rice leaves were sprayed with 5.0 μmol·L−1 Hemin or 25.0 μmol·L−1 ZnPP (Zinc protoporphyrin IX) at the three leaf and one heart stage, followed by an imposed salt stress treatment regime (50.0 mmol·L−1 sodium chloride (NaCl)). The findings revealed that NaCl stress increased antioxidant enzymes activities and decreased the content of nonenzymatic antioxidants such as ascorbate (AsA) and glutathione (GSH). Furthermore, the content of osmoregulatory substances like soluble proteins and proline was raised. Moreover, salt stress increased reactive oxygen species (ROS) content in the leaves of the two varieties. However, spraying with Hemin increased the activities of antioxidants such as superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) and accelerated AsA-GSH cycling to remove excess ROS. In summary, Hemin reduced the effect of salt stress on the physiological characteristics of rice leaves due to improved antioxidant defense mechanisms that impeded lipid peroxidation. Thus, Hemin was demonstrated to lessen the damage caused by salt stress

    Prohexadione-calcium alleviates the leaf and root damage caused by salt stress in rice (Oryza sativa L.) at the tillering stage.

    No full text
    Salt stress, as a principal abiotic stress, harms the growth and metabolism of rice, thus affecting its yield and quality. The tillering stage is the key growth period that controls rice yield. Prohexadione-calcium (Pro-Ca) can increase the lodging resistance of plants by reducing plant height, but its effects on rice leaves and roots at the tillering stage under salt stress are still unclear. This study aimed to evaluate the ability of foliar spraying of Pro-Ca to regulate growth quality at the rice tillering stage under salt stress. The results showed that salt stress reduced the tillering ability of the rice and the antioxidant enzyme activity in the roots. Salt stress also reduced the net photosynthetic rate (Pn), stomatal conductance (Gs) and intercellular CO2 concentration (Ci) of the rice leaves and increased the contents of osmotic regulatory substances in the leaves and roots. The application of exogenous Pro-Ca onto the leaves increased the tiller number of the rice under salt stress and significantly increased the photosynthetic capacity of the leaves. Additionally, it increased the activities of antioxidant enzymes and the AsA content. The contents of an osmotic regulation substance, malondialdehyde (MDA), and H2O2 in the leaves and roots also decreased. These results suggested that Pro-Ca can increase the tillering ability, photosynthetic capacity, osmotic adjustment substance content levels and antioxidant enzyme activity levels in rice and reduce membrane lipid peroxidation, thus improving the salt tolerance of rice at the tillering stage

    Efficacy of Immunization against a Novel Synthetic 13-Amino Acid Betaglycan-Binding Peptide Sequence of Inhibin α Subunit on Promoting Fertility in Female Rats

    No full text
    Inhibins suppress the FSH production in pituitary gonadotrope cells by robustly antagonizing activin signaling by competitively binding to activin type II receptors (ACTR II). The binding of inhibin A to ACTR II requires the presence of its co-receptor, namely, betaglycan. In humans, the critical binding site for betaglycan to inhibin A was identified on the inhibin α subunit. Through conservation analysis, we found that a core 13-amino-acid peptide sequence within the betaglycan-binding epitope on human inhibin α subunit is highly conserved across species. Based on the tandem sequence of such a conserved 13-amino-acid betaglycan-binding epitope (INHα13AA-T), we developed a novel inhibin vaccine and tested its efficacy in promoting female fertility using the female rat as a model. Compared with placebo-immunized controls, INHα13AA-T immunization induced a marked (p p p Fshb transcription and increased (p < 0.05) serum FSH and 17β-estradiol concentrations. In summary, active immunization against INHα13AA-T potently increased FSH levels, ovarian follicle development, ovulation rate and litter sizes, thus causing super-fertility in females. Therefore, immunization against INHα13AA is a promising alternative to the conventional approach of multiple ovulation and super-fertility in mammals

    Detecting and imaging of SO2 derivatives in living cells with zero cross-talk colorimetric mitochondria-targeted fluorescent probe

    No full text
    It is well known that excessive levels of sulfur dioxide and its derivatives are con-nected to diverse diseases. Therefore, developing highly sensitive probes to detect and monitor sulfite in living cells is important for the diagnosis of disease and the study of biochemical processes in vivo. In this report, two zero cross-talk ratiometric fluorescent probes were synthesized (CA-ID-MC and CA-BI-MC), which were de-rived from carbazole-indolenine ÄŽ -conjugated system for effective detection of sul-fite in living cells. Observably, CA-BI-MC exhibited the largest emission shift of 157 nm from 617 to 460 nm with the addition of various concentrations of sulfite, which is beneficial for high-resolution imaging of the sulfite. CA-BI-MC also exhibits high sensitivity, as well as low cytotoxicity. More importantly, this probe successfully located mitochondria and sensed the sulfite in HeLa cells caused by exogenous stimulation.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author
    corecore