127 research outputs found
Impact of Hypoxia on Radiation-Based Therapies for Liver Cancer
Background: Hypoxia, a state of low oxygen level within a tissue, is often present in primary and secondary liver tumors. At the molecular level, the tumor cells’ response to hypoxic stress induces proteomic and genomic changes which are largely regulated by proteins called hypoxia-induced factors (HIF). These proteins have been found to drive tumor progression and cause resistance to drug- and radiation-based therapies, ultimately contributing to a tumor’s poor prognosis. Several imaging modalities have been developed to visualize tissue hypoxia, providing insight into a tumor’s microbiology. Methods: A systematic literature search was conducted in PubMed, EMBASE, Cochrane, and Google Scholar for all reports related to hypoxia on liver tumors. All relevant studies were summarized. Results: This review will focus on the impact of hypoxia on liver tumors and review PET-, MRI-, and SPECT-based imaging modalities that have been developed to predict and assess a tumor’s response to radiation therapy, with a focus on liver cancers. Conclusion: While there are numerous studies that have evaluated the impact of hypoxia on tumor outcomes, there remains a relative paucity of data evaluating and quantifying hypoxia within the liver. Novel and developing non-invasive imaging techniques able to provide functional and physiological information on tumor hypoxia within the liver may be able to assist in the treatment planning of primary and metastatic liver lesions
Investigation of bias current and modulation frequency dependences of detectivity of YBCO TES and the effects of coating of Cu-C composite absorber layer
Bolometric response and noise characteristics of YBCO superconductor transition edge IR detectors with relatively sharp transition and its resulting detectivity are investigated both theoretically and experimentally. The magnitude of response of a fabricated device was obtained for different bias currents and modulation frequencies. Using the measured and calculated bolometric response and noise characteristics, we found and analyzed the device detectivity versus frequency for different bias currents. The detectivity versus chopping frequency of the device did not decrease following the response strongly, due to the decrease of the noise at higher frequencies up to 1 kHz, resulting in maximum detectivity around the modulation frequency of 100 Hz. We also improved the responsivity of the device through the increase of the surface absorption by using a novel infrared absorber, which is made of a copper-carbon composite, coated in a low-temperature process. Within the modulation frequency range studied in this paper, comparison of device detectivity before and after coating is also presented. © 2009 IEEE
A tecpr2 knockout mouse exhibits age-dependent neuroaxonal dystrophy associated with autophagosome accumulation
Zonation patterns, composition and diversity of macroalgal communities in the eastern coasts of Qeshm Island, Persian Gulf, Iran
Reactive friction-stir processing of nanocomposites: effects of thermal history on microstructure–mechanical property relationships
Grain size distribution after similar and dissimilar gas tungsten arc welding of a ferritic stainless steel
In this study, gas tungsten arc welding of ferritic stainless steel and grain
size distribution in heat affected zone of the welded samples were
investigated. Both similar and dissimilar arc welding operations were
considered where in dissimilar welding joining of stainless steel to mild
steel was examined. In the first stage, a three-dimensional model was
developed to evaluate temperature field during and after arc welding while
the model was performed using finite element software, ANSYS. Then, the
effects of welding heat input and dissimilarity of the joint on the weld pool
shape and grain growth in HAZ of stainless steel was investigated by means of
model predictions and experimental observations. The results show that the
similar joint produces wider HAZ and considerably larger grain size structure
while in the dissimilar welds, the low carbon part acts as an effective heat
sink and prevents the grain growth in the stainless steel side as well
reduces the welding maximum temperature
Effect of the nano-structure Cu-carbon composite absorber layer on the response of superconductive YBCO TEBs
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