418 research outputs found

    Bidirectional two colored light emission from stress-activated ZnS-microparticles-embedded polydimethylsiloxane elastomer films

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    Bidirectional two-colored mechanoluminescent light emission has been demonstrated by unifying two polydimethylsiloxane elastomer layers functionalized with zinc sulfide doped with Cu (ZnS:Cu) or Cu and Mn (ZnS:Cu,Mn). The bilayered composite films are simply fabricated by dispensing uncured ZnS:Cu,Mn + PDMS onto previously spin-coated and ardened ZnS:Cu + PDMS film. The robust PDMS-PDMS bonding yields a ilm which can simultaneously emit light with color coordinates of (0.25, 0.56) and (0.50, 0.48), similar to the intrinsic colors of ZnS:Cu and ZnS:Cu,Mn, respectively. Composite films can emit light in upper and lower directions without fracture when it is stretched. © 2013 Optical Society of America.1

    Torsional Vibration Transduction in a Solid Shaft by MPTs

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    In this study, we aim to investigate the feasibility to use MPTs (Magnetostrictive Patch Transducers) for torsional vibration measurement in solid ferromagnetic cylinders. MPTs consisting of thin magnetostrictive patches, permanent magnets and a solenoid coil have been widely used for elastic wave transduction in the ultrasound frequency range [1] but they have been seldom used for sonic-frequency range vibration measurement, in spite of their unique wireless transduction characteristics. While a MPT was used in Ref. [2] to perform torsional modal testing in a hollow cylinder or a pipe having relatively small torsional rigidity, no investigation has been reported yet on the use of MPTs in “solid” “ferromagnetic” shafts, common torsional power carrying elements in machines.While we will be mainly focused here on the torsional wave measurement in stationary shafts, the MPT-based torsional measurement can be also applied to rotating shafts. Because the torsional rigidities of solid shafts are much larger than those of hollow cylinders of the same radii, it is important to find optimal MPT configurations, such as the optimal number of rectangular patches to be installed around the surface of a solid shaft. Thereby, we performed numerical investigations and accordingly designed a series of experiments for torsional vibration testing in steel shafts. The actual modal testing experiments with the designed MPTs were found to predict the torsional Eigen-frequencies and Eigen-modes that agree well with the theoretical predictions. Also the relation between the measured vibration signals from MPTs and those from strain gages was checked experimentally and in fact, the experimental result favorably agreed with the theoretical prediction. Potential applications of the MPT-based torsional vibration measurement technique in rotating solid shafts for structural health monitoring are also briefly discussed

    Akt1-Inhibitor of DNA binding2 is essential for growth cone formation and axon growth and promotes central nervous system axon regeneration.

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    Mechanistic studies of axon growth during development are beneficial to the search for neuron-intrinsic regulators of axon regeneration. Here, we discovered that, in the developing neuron from rat, Akt signaling regulates axon growth and growth cone formation through phosphorylation of serine 14 (S14) on Inhibitor of DNA binding 2 (Id2). This enhances Id2 protein stability by means of escape from proteasomal degradation, and steers its localization to the growth cone, where Id2 interacts with radixin that is critical for growth cone formation. Knockdown of Id2, or abrogation of Id2 phosphorylation at S14, greatly impairs axon growth and the architecture of growth cone. Intriguingly, reinstatement of Akt/Id2 signaling after injury in mouse hippocampal slices redeemed growth promoting ability, leading to obvious axon regeneration. Our results suggest that Akt/Id2 signaling is a key module for growth cone formation and axon growth, and its augmentation plays a potential role in CNS axonal regeneration

    Prevalence of sarcopenia and sarcopenic obesity in Korean adults: The Korean Sarcopenic Obesity Study (KSOS)

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    *Context:* Sarcopenic obesity (SO), a combination of excess weight and reduced muscle mass and/or strength, is suggested to be associated with an increased risk of adverse health outcomes. 
*Objectives:* To examine the prevalence and characteristics of Sarcopenic and SO defined by using different indices such as Appendicular Skeletal muscle Mass (ASM)/height^2^ and Skeletal Muscle Index (SMI (%): skeletal muscle mass (kg)/weight (kg) × 100) for Korean adults. 
*Methods:* 591 participants were recruited from the Korean Sarcopenic Obesity Study (KSOS) which is an ongoing prospective observational cohort study. Analysis was conducted in 526 participants (328 women, 198 men) who had complete data on body composition using Dual X-ray absorptiometry and computed tomography. 
*Results:* The prevalence of sarcopenia and SO increases with aging. Using two or more standard deviations (SD) of ASM/height^2^ below reference values from young, healthy adults as a definition of sarcopenia, the prevalence of sarcopenia and SO was 6.3% and 1.3% in men and 4.1% and 1.7% in women over 60 years of age. However, using two or more SD of SMI, the prevalence of sarcopenia and SO was 5.1% and 5.1% respectively in men and 14.2% and 12.5% respectively in women. As defined by SMI, subjects with SO had 3 times the risk of metabolic syndrome (OR = 3.03, 95% confidence interval (CI) = 1.26-7.26) and subjects with non-sarcopenic obesity had approximately 2 times the risk of metabolic syndrome (OR = 1.89, 95% CI = 1.18-3.02) compared with normal subjects. 
*Conclusion:* Obese subjects with relative sarcopenia were associated with a greater likelihood for metabolic syndrome. As Koreans were more obese and aging, the prevalence of SO and its impact on health outcomes are estimated to be rapidly grow. Further research is requested to establish the definition, cause and consequences of SO.
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    Gastroprotective effects of the isopropanol extract of Artemisia princeps and its gastroretentive floating tablets on gastric mucosal injury

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    In this study, we investigated the gastroprotective effect of an isopropanol extract from the aerial parts of Artemisia princeps (IPAP) and developed a gastroretentive floating tablet of IPAP (IPAP-FR) for maximized local gastroprotective effects. Pre-treatment with IPAP ameliorated the gastric mucosal hemorrhagic lesions in ethanol/HCl- or indomethacin-treated rats. IPAP decreased mucosal hemorrhage of gastric ulcers induced by ethanol or indomethacin plus pyloric ligation in rats. The optimized floating tablet, IPAP-FR, floated on medium surface with more sustained eupatilin release compared to the non-floating control tablet. X-ray photographs in beagle dogs showed that IPAP-FR was retained for >2 h in the stomach. In the ethanol-induced gastric ulcer rat model, the gastric hemorrhagic lesion was improved more substantially with IPAP-FR compared to the non-floating control tablet. Based on these data, our data suggest that IPAP-FR has an improved therapeutic potential for the treatment of gastric ulcer

    The combination effect of sodium butyrate and 5-Aza-2'-deoxycytidine on radiosensitivity in RKO colorectal cancer and MCF-7 breast cancer cell lines

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    <p>Abstract</p> <p>Background</p> <p>The overall level of chromatin compaction is an important mechanism of radiosensitivity, and modification of DNA methylation and histone deacetylation may increase radiosensitivity by altering chromatin compaction. In this study, we investigated the effect of a demethylating agent, a histone deacetylase(HDAC) inhibitor, and the two agents combined on radiosensitivity in human colon and breast cancer cell lines.</p> <p>Methods</p> <p>In this study, we used RKO colorectal cancer cell line and MCF-7 breast cancer cell lines and normal colon cell lines. On each of the cell lines, we used three different agents: the HDAC inhibitor sodium butyrate(SB), the demethylating agent 5-Aza-2'-deoxycytidine(5-aza-DC), and radiation. We then estimated the percentage of the cell survival using the XTT method and experimented to determine if there was an augmentation in the therapeutic effect by using different combinations of the two or three of the treatment methods.</p> <p>Results</p> <p>After treatment of each cell lines with 5-aza-DC, SB and 6 grays of radiation, we observed that the survival fraction was lower after the treatment with 5-aza-DC or SB than with radiation alone in RKO and MCF-7 cell lines(p < 0.001). The survival fraction was lowest when the two agents, 5-aza-DC and SB were combined with radiation in both RKO and MCF-cell lines.</p> <p>Conclusion</p> <p>In conclusion, 5-aza-DC and SB can enhance radiosensitivity in both MCF-7 and RKO cell lines. The combination effect of a demethylating agent and an HDAC inhibitor is more effective than that of single agent treatment in both breast and colon cancer cell lines.</p

    Small testes: clinical characteristics and ultrasonographic findings

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    The purpose of this pictorial essay is to describe the ultrasonographic and clinical findings of patients with small testes due to a wide range of causes. We retrospectively reviewed the ultrasonographic and clinical findings of various causes of small testes. We present various causes of small testes on ultrasonography including Klinefelter syndrome, testicular torsion, mumps orchitis, inguinal hernia, cryptorchidism, varicocele, and trauma. On ultrasonography, small testes in patients with testicular torsion, mumps orchitis, and trauma usually showed heterogeneous echogenicity. Atrophic testes were homogeneously hypoechoic in patients with cryptorchidism and inguinal hernia and were isoechoic to the normal testis in patients with varicocele. Klinefelter syndrome patients had small hyperechoic or hypoechoic nodules, but the echogenicity of the remnant portion of the testes was homogeneous. Ultrasonography is helpful for detecting small testes and for the differential diagnosis of the various possible causes of small testes
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