988 research outputs found
Creep, Strength and Moisture Absorption of Adhesive Bonded FRP Joints
The effects of the environment on adhesive bonded single lap joints formed using XMC-3 and SMC-R50 composites were investigated. Tests were performed at temperatures of 23C and 93C with test coupons immersed in air, water, and 5% NaCl water mixture. The weight changes of both bonded joints (XMC-3 to SMC-R50 and SMC-R50 to SMC-R50) and unbonded materials were measured. Data were also ob tained showing the effects of moisture, temperature, and applied load on changes in weight, on creep deformation, lap shear strength, and separation modes of the joints.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68649/2/10.1177_073168448500400206.pd
Induction of Non-Targeted Stress Responses in Mammary Tissues by Heavy Ions
Purpose
Side effects related to radiation exposures are based primarily on the assumption that the detrimental effects of radiation occur in directly irradiated cells. However, several studies have reported over the years of radiation-induced non-targeted/ abscopal effects in vivo that challenge this paradigm. There is evidence that Cyclooxygenase-2 (COX2) plays an important role in modulating non-targeted effects, including DNA damages in vitro and mutagenesis in vivo. While most reports on radiation-induced non-targeted response utilize x-rays, there is little information available for heavy ions.
Methods and Materials
Adult female transgenic gpt delta mice were exposed to an equitoxic dose of either carbon or argon particles using the Heavy Ion Medical Accelerator in Chiba (HIMAC) at the National Institute of Radiological Sciences (NIRS) in Japan. The mice were stratified into 4 groups of 5 animals each: Control; animals irradiated under full shielding (Sham-irradiated); animals receiving whole body irradiation (WBIR); and animals receiving partial body irradiation (PBIR) to the lower abdomen with a 1 x 1 cm2 field. The doses used in the carbon ion group (4.5 Gy) and in argon particle group (1.5 Gy) have a relative biological effectiveness equivalent to a 5 Gy dose of x-rays. 24 hours after irradiation, breast tissues in and out of the irradiated field were harvested for analysis. Induction of COX2, 8-hydroxydeoxyguanosine (8-OHdG), phosphorylated histone H2AX (γ-H2AX), and apoptosis-related cysteine protease-3 (Caspase-3) antibodies were examined in the four categories of breast tissues using immunohistochemical techniques. Analysis was performed by measuring the intensity of more than 20 individual microscopic fields and comparing the relative fold difference.
Results
In the carbon ion group, the relative fold increase in COX2 expression was 1.01 in sham-irradiated group (p > 0.05), 3.07 in PBIR (p 0.05), 11.31 in PBIR (p 0.05), 8.41 in PBIR (p < 0.05) and 10.59 in WBIR (p < 0.05). Results for the argon particle therapy group showed a similar magnitude of changes in the various biological endpoints examined. There was no statistical significance observed in Caspase-3 expression among the 4 groups.
Conclusions
Our data show that both carbon and argon ions induced non-targeted, out of field induction of COX2 and DNA damages in breast tissues. These effects may pose new challenges to evaluate the risks associated with radiation exposure and understanding radiation-induced side effects
Creep, Strength and Moisture Absorption of Adhesive Bonded FRP Joints*
ABSTRACT The effects of the environment on adhesive bonded single lap joints formed using XMC-3 and SMC-R50 composites were investigated. Tests were performed at temperatures of 23C and 93C with test coupons immersed in air, water, and 5% NaClwater mixture. The weight changes of both bonded joints (XMC-3 to SMC-R50 and SMC-R50 to SMC-R50) and unbonded materials were measured. Data were also obtained showing the effects of moisture, temperature, and applied load on changes in weight, on creep deformation, lap shear strength, and separation modes of the joints
An R2R3 MYB transcription factor associated with regulation of the anthocyanin biosynthetic pathway in Rosaceae
<p>Abstract</p> <p>Background</p> <p>The control of plant anthocyanin accumulation is via transcriptional regulation of the genes encoding the biosynthetic enzymes. A key activator appears to be an R2R3 MYB transcription factor. In apple fruit, skin anthocyanin levels are controlled by a gene called <it>MYBA </it>or <it>MYB1</it>, while the gene determining fruit flesh and foliage anthocyanin has been termed <it>MYB10</it>. In order to further understand tissue-specific anthocyanin regulation we have isolated orthologous <it>MYB </it>genes from all the commercially important rosaceous species.</p> <p>Results</p> <p>We use gene specific primers to show that the three MYB activators of apple anthocyanin (<it>MYB10/MYB1/MYBA) </it>are likely alleles of each other. MYB transcription factors, with high sequence identity to the apple gene were isolated from across the rosaceous family (e.g. apples, pears, plums, cherries, peaches, raspberries, rose, strawberry). Key identifying amino acid residues were found in both the DNA-binding and C-terminal domains of these MYBs. The expression of these <it>MYB10 </it>genes correlates with fruit and flower anthocyanin levels. Their function was tested in tobacco and strawberry. In tobacco, these MYBs were shown to induce the anthocyanin pathway when co-expressed with bHLHs, while over-expression of strawberry and apple genes in the crop of origin elevates anthocyanins.</p> <p>Conclusions</p> <p>This family-wide study of rosaceous R2R3 MYBs provides insight into the evolution of this plant trait. It has implications for the development of new coloured fruit and flowers, as well as aiding the understanding of temporal-spatial colour change.</p
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Inhibition of ATM kinase upregulates levels of cell death induced by cannabidiol and γ-irradiation in human glioblastoma cells
Despite advances in glioblastoma (GBM) therapy, prognosis of the disease remains poor with a low survival rate. Cannabidiol (CBD) can induce cell death and enhance radiosensitivity of GBM but not normal astrocytes. Inhibition of ATM kinase is an alternative mechanism for radiosensitization of cancer cells. In this study, we increased the cytotoxic effects of the combination of CBD and gamma-irradiation in GBM cells through additional inhibition of ATM kinase with KU60019, a small molecule inhibitor of ATM kinase. We observed in GBM cells treated by CBD, gamma-irradiation and KU60019 high levels of apoptosis together with strong upregulation of the percentage of G2/M-arrested cells, blockade of cell proliferation and a massive production of pro-inflammatory cytokines. Overall, these changes caused both apoptotic and non-apoptotic inflammation-linked cell death. Furthermore, via JNK-AP1 activation in concert with active NF-(kappa)B, CBD upregulated gene and protein expression of DR5/TRAIL-R2 and sensitize GBM cells to TRAIL-induced apoptosis. In contrast, CBD notably decreased in GBM surface levels of PD-L1, a critical immune checkpoint agent for T-lymphocytes. We also used in the present study TS543 human proneural glioma cells that were grown as spheroid culture. TS543 neurospheres exhibited dramatic sensitivity to CBD-mediated killing that was additionally increased in combination with gamma-irradiation and KU60019. In conclusion, treatment of human GBM by the triple combination (CBD, gamma-irradiation and KU60019) could significantly increase cell death levels in vitro and potentially improve the therapeutic ratio of GBM
Gattini 2010: Cutting Edge Science at the Bottom of the World
The high altitude Antarctic sites of Dome A and the South Pole offer intriguing locations for future large scale optical astronomical
Observatories. The Gattini project was created to measure the optical
sky brightness, large area cloud cover and aurora of the winter-time
sky above such high altitude Antarctic sites. The Gattini-DomeA camera
was installed on the PLATO instrument module as part of the Chinese-led
traverse to the highest point on the Antarctic plateau in January 2008.
This single automated wide field camera contains a suite of Bessel
photometric filters (B, V, R) and a long-pass red filter for the
detection and monitoring of OH emission. We have in hand one complete
winter-time dataset (2009) from the camera that was recently returned
in April 2010.
The Gattini-South Pole UV camera is a wide-field optical camera that in
2011 will measure for the first time the UV properties of the
winter-time sky above the South Pole dark sector. This unique dataset
will consist of frequent images taken in both broadband U and B filters
in addition to high resolution (R similar to 5000) long slit
spectroscopy over a narrow bandwidth of the central field. The camera
is a proof of concept for the 2m-class Antarctic Cosmic Web Imager
telescope, a dedicated experiment to directly detect and map the
redshifted lyman alpha fluorescence or Cosmic Web emission we believe
possible due to the unique geographical qualities of the site.
We present the current status of both projects
Facile preparation of starch-based electroconductive films with ionic liquid
Here, we discovered that starch could be straightforwardly processed into optically-transparent electroconductive films, by compression molding at a relatively mild temperature (55 °C or 65 °C), much lower than those commonly used in biopolymer melt processing (typically over 150 °C). Such significantly-reduced processing temperature was achieved with the use of an ionic liquid plasticizer, 1-ethyl-3-methylimidazolium acetate ([C2mim][OAc]). A higher [C2mim][OAc] content, lower processing temperature (55 °C), and/or higher relative humidity (RH) (75%) during the sample post-processing conditioning, suppressed the crystallinity of the processed material. The original A-type crystalline structure of starch was eliminated, although small amounts of B-type and V-type crystals were formed subsequently. The starch crystallinity could be linked to the mechanical properties of the films. Moreover, the processing destroyed the original lamellar structure of starch, and the amorphous starch processed with [C2mim][OAc]/water could aggregate on the nanoscale. The films displayed excellent electrical conductivity (> 10−3 S/cm), which was higher with a lower processing temperature (55 °C) and a higher conditioning RH (75%). The incorporation of [C2mim][OAc] reduced the thermal decomposition temperature of starch by 30 °K, while the formulation and processing conditions did not affect the film thermal stability
Deep-sea coral evidence for lower Southern Ocean surface nitrate concentrations during the last ice age
The Southern Ocean regulates the ocean’s biological sequestration of CO_2 and is widely suspected to underpin much of the ice age decline in atmospheric CO_2 concentration, but the specific changes in the region are debated. Although more complete drawdown of surface nutrients by phytoplankton during the ice ages is supported by some sediment core-based measurements, the use of different proxies in different regions has precluded a unified view of Southern Ocean biogeochemical change. Here, we report measurements of the ^(15)N/^(14)N of fossil-bound organic matter in the stony deep-sea coral Desmophyllum dianthus, a tool for reconstructing surface ocean nutrient conditions. The central robust observation is of higher ^(15)N/^(14)N across the Southern Ocean during the Last Glacial Maximum (LGM), 18–25 thousand years ago. These data suggest a reduced summer surface nitrate concentration in both the Antarctic and Subantarctic Zones during the LGM, with little surface nitrate transport between them. After the ice age, the increase in Antarctic surface nitrate occurred through the deglaciation and continued in the Holocene. The rise in Subantarctic surface nitrate appears to have had both early deglacial and late deglacial/Holocene components, preliminarily attributed to the end of Subantarctic iron fertilization and increasing nitrate input from the surface Antarctic Zone, respectively
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