53 research outputs found

    Wave energy evolution of Yellow river delta induced by climate changes

    Get PDF
    Nowadays, climate changes are reported by many researches including IPCC, which might bring many\ud problems in coastal engineering. In the present work, the evolution of extreme wave and wave energy around Yellow\ud River Delta (YRD) induced by climate changes was analyzed since coastal erosion situation is becoming more and\ud more seriously as result of reducing of upstream sediment. The Yellow River is very famous in the world because of her\ud carrying out huge sediment before. However, from 1990 to now, sediment into seas carried by the Yellow River\ud decreases due to the construction of several dams in the upstream. So many coastal structures are being threatened by\ud wave and wave induced erosion. Based on the results given in former researches, the possible SLR around YRD in the\ud past several decades are assumed as 0.2m, 0.5m and 1.0m. Thirdly, evolution of wave energy and wave-induced bottom\ud shear stress (WIBSS) are studied by numerical simulation under the above three possible SLRs. Wave model SWAN is\ud adopted to simulate wave. The wave parameters including wave height, wave energy and WIBSS with effects of\ud possible changes are predicted numerically, which help government or constructers to design coastal protection\ud engineering. Results by now show that the obvious enhancements of wave energy and WIBSS appear in zones\ud shallower than 5 water depth contours. More attention should be paid to the security of coastal structures and sediment\ud transport under climate change in this area

    Cartilage Engineering: Optimization of Media for Chondrogenic Differentiation In Vitro

    Get PDF
    Lower back pain from intervertebral disc injury affects around 84% of the population at some point in their life, which at its worst may cause total immobilization. This pain can only be temporarily relieved by spinal fusion or intervertebral disc replacement; however, both of these cause loss of natural motion in patients by removing damaged fibrocartilage discs. While these techniques help mitigate pain briefly, no permanent solution exists currently to both relieve pain and preserve natural motion. My work may be a solution by eventually providing patient-specific implants that resemble native tissue in the regeneration process that could be absorbed and remodeled by the body. The purpose of this study is to use tunable type I oligomeric collagen matrices for culturing of patient-derived stem cells to optimize chondrogenic media. Human adipose stem cells (hASCs) were passaged and used in conjunction with oligomer collagen, which was polymerized as cell/oligomer mixtures and plastically compressed to a density of 24.5mg/mL, with 4.5x105 cells per sample. These cell-matrix constructs were cultured with different media and supplements (namely TGF-β (3) and L-ascorbic-acid-2-phosphate) for 1 week. Safranin-o staining was used to detect sulfated glycosaminoglycans, a direct measure of chondrogenesis. Preliminary results show that supplemented DMEM media has the most chondrogenic potential, but further study is required. These results will be used to further improve the process of chondrogenesis in vitro in order to develop fibrocartilage constructs for use in vivo, eventually allowing for implantable constructs that both preserve natural disc height and relieve pain more permanently

    Stem cell-derived tissue-engineered constructs for hemilaryngeal reconstruction

    Get PDF
    OBJECTIVES: As an initial step toward our goal of developing a completely tissue-engineered larynx, the aim of this study was to describe and compare three strategies of creating tissue-engineered muscle-polymer constructs for hemilaryngeal reconstruction. METHODS: Cartilage-mimicking polymer was developed from electrospun poly(D,L-lactide-co-ε-caprolactone) (PCL). Primary muscle progenitor cell cultures were derived from syngeneic F344 rat skeletal muscle biopsies. Twenty F344 rats underwent resection of the outer hemilaryngeal cartilage with the underlying laryngeal adductor muscle. The defects were repaired with muscle stem cell-derived muscle-PCL constructs (5 animals), myotube-derived muscle-PCL constructs (5 animals), motor end plate-expressing muscle-PCL constructs (5 animals), or PCL alone (controls; 5 animals). The outcome measures at 1 month included animal survival, muscle thickness, and innervation status as determined by electromyography and immunohistochemistry. RESULTS: All of the animals survived the 1-month implant period and had appropriate weight gain. The group that received motor end plate-expressing muscle-PCL constructs demonstrated the greatest muscle thickness and the strongest innervation, according to electromyographic activity and the percentage of motor end plates that had nerve contact. CONCLUSIONS: Although all of the tissue-engineered constructs provided effective reconstruction, those that expressed motor end plates before implantation yielded muscle that was more strongly innervated and viable. This finding suggests that this novel approach may be useful in the development of a tissue-engineered laryngeal replacement

    Mesenchymal stem cells protect against obstruction-induced renal fibrosis by decreasing STAT3 activation and STAT3-dependent MMP-9 production

    Get PDF
    STAT3 is a transcription factor implicated in renal fibrotic injury, but the role of STAT3 in mesenchymal stem cell (MSC)-induced renoprotection during renal fibrosis remains unknown. We hypothesized that MSCs protect against obstruction-induced renal fibrosis by downregulating STAT3 activation and STAT3-induced matrix metalloproteinase-9 (MMP-9) expression. Male Sprague-Dawley rats underwent renal arterial injection of vehicle or MSCs (1 × 106/rat) immediately before sham operation or induction of unilateral ureteral obstruction (UUO). The kidneys were harvested after 4 wk and analyzed for collagen I and III gene expression, collagen deposition (Masson's trichrome), fibronectin, α-smooth muscle actin, active STAT3 (p-STAT3), MMP-9, and tissue inhibitor of matrix metalloproteinases 1 (TIMP-1) expression. In a separate arm, the STAT3 inhibitor S3I-201 (10 mg/kg) vs. vehicle was administered to rats intraperitoneally just after induction of UUO and daily for 14 days thereafter. The kidneys were harvested after 2 wk and analyzed for p-STAT3 and MMP-9 expression, and collagen and fibronectin deposition. Renal obstruction induced a significant increase in collagen, fibronectin, α-SMA, p-STAT3, MMP-9, and TIMP-1 expression while exogenously administered MSCs significantly reduced these indicators of obstruction-induced renal fibrosis. STAT3 inhibition with S3I-201 significantly reduced obstruction-induced MMP-9 expression and tubulointerstitial fibrosis. These results demonstrate that MSCs protect against obstruction-induced renal fibrosis, in part, by decreasing STAT3 activation and STAT3-dependent MMP-9 production

    Genome-wide association study of lung adenocarcinoma in East Asia and comparison with a European population.

    Get PDF
    Lung adenocarcinoma is the most common type of lung cancer. Known risk variants explain only a small fraction of lung adenocarcinoma heritability. Here, we conducted a two-stage genome-wide association study of lung adenocarcinoma of East Asian ancestry (21,658 cases and 150,676 controls; 54.5% never-smokers) and identified 12 novel susceptibility variants, bringing the total number to 28 at 25 independent loci. Transcriptome-wide association analyses together with colocalization studies using a Taiwanese lung expression quantitative trait loci dataset (n = 115) identified novel candidate genes, including FADS1 at 11q12 and ELF5 at 11p13. In a multi-ancestry meta-analysis of East Asian and European studies, four loci were identified at 2p11, 4q32, 16q23, and 18q12. At the same time, most of our findings in East Asian populations showed no evidence of association in European populations. In our studies drawn from East Asian populations, a polygenic risk score based on the 25 loci had a stronger association in never-smokers vs. individuals with a history of smoking (Pinteraction = 0.0058). These findings provide new insights into the etiology of lung adenocarcinoma in individuals from East Asian populations, which could be important in developing translational applications

    Genome-wide association study of lung adenocarcinoma in East Asia and comparison with a European population

    Get PDF
    Lung adenocarcinoma is the most common type of lung cancer. Known risk variants explain only a small fraction of lung adenocarcinoma heritability. Here, we conducted a two-stage genome-wide association study of lung adenocarcinoma of East Asian ancestry (21,658 cases and 150,676 controls; 54.5% never-smokers) and identified 12 novel susceptibility variants, bringing the total number to 28 at 25 independent loci. Transcriptome-wide association analyses together with colocalization studies using a Taiwanese lung expression quantitative trait loci dataset (n = 115) identified novel candidate genes, including FADS1 at 11q12 and ELF5 at 11p13. In a multi-ancestry meta-analysis of East Asian and European studies, four loci were identified at 2p11, 4q32, 16q23, and 18q12. At the same time, most of our findings in East Asian populations showed no evidence of association in European populations. In our studies drawn from East Asian populations, a polygenic risk score based on the 25 loci had a stronger association in never-smokers vs. individuals with a history of smoking (P interaction  = 0.0058). These findings provide new insights into the etiology of lung adenocarcinoma in individuals from East Asian populations, which could be important in developing translational applications

    Automated fitting of X-ray powder diffraction patterns from interstratified phyllosilicates

    No full text
    NEWMOD, developed by R.C. Reynolds, Jr., has been an important tool for evaluating quantitatively X-ray diffraction (XRD) patterns from interstratified clay minerals for more than 20 years. However, a significant drawback to the NEWMOD approach is that analyses are done by forward simulation, making results sensitive to user input and starting-model assumptions. In the present study, a reverse-fitting procedure was implemented in a new program, FITMOD, which automatically minimizes the differences between experimental and simulated XRD patterns. The differences are minimized by varying model parameters (such as Reichweite, crystal-size distribution, cation content, type of disorder, etc.) using the downhill simplex method. The downhill simplex method is a non-linearoptimization technique for determining minima of functions. This method does not require calculation of the derivatives of the functions being minimized, an important consideration with many of the parameters in NEWMOD-type simulations. Instead, the downhill simplex method calculates pseudo-derivatives by evaluating sufficient points to define a derivative for each independent variable. The performance of FITMOD was evaluated by fitting a series of synthetic XRD patterns generated by NEWMOD+, yielding agreement factors, R, of <0.3%. As long as the correct interstratified system was specified (e.g. illite-smectite), excellent fits were obtained irrespective of the starting parameters for the simulations. FITMOD was also tested using experimental XRD patterns, which gave very good fits, in agreement with previously published results. The optimization routine yields good fits for both synthetic and experimental XRD profiles in a reasonable time, with the possibility of varying all important structural parameters. FITMOD automatically provides optimum fits to experimental XRD data without operator bias, and fitting efficiency and accuracy were, therefore, significantly improved

    Newmod+, a new version of the newmod program for interpretingx-ray powder diffraction patterns from interstratified clay minerals

    No full text
    NEWMOD was developed by R.C. Reynolds, Jr., for the study of two-component interstratifications of clay minerals. One-dimensional X-ray diffraction (XRD) profiles of an interstratified system of two clay minerals can be simulated using NEWMOD, given a set of parameters that describes instrumental factors, the chemical composition of the system (e.g. the concentration of Fe and interlayer cations), and structural parameters (e.g. proportions of the two components, the nature of ordering, and crystallite size distribution). NEWMOD has served as the standard method for quantitatively evaluating interstratified clay minerals for >20 y. However, the efficiency and accuracy of quantitative analysis using NEWMOD have been limited by the graphical user interface (GUI), by the lack of quantitative measures of the goodness-of-fit between the experimental and simulated XRD patterns, and by inaccuracies in some structure models used in NEWMOD. To overcome these difficulties, NEWMOD+ was coded in Visual C++ using the NEWMOD architecture, incorporating recent progress in the structures of clay minerals into a more user-friendly GUI, greatly facilitating efficient and accurate fitting. Quantitative fitting parameters (unweighted R-factor, R, weighted R-factor, R, expected R-factor, R, and chisquare, X) are included, along with numerous other features such as a powerful series generator, which greatly simplifies the generation of multiple simulations and makes NEWMOD+ particularly valuable for teaching
    • …
    corecore