4,233 research outputs found
A research on the recursive value and general terms of the analogue Euler zeta function on positive integers
VIABILITY, FATTY ACID COMPOSITION, AND STRUCTURE OF THE CORALLINE ALGA CORALLINA PILULIFERA
The decrease in the seaweed flora in some rocky areas, known as algal whitening or barren ground, is associated with some species of coralline algae. To determine the biological characteristics of a representative species of branched coralline alga, the number of medullary tiers was counted and ranged from 12 to 16. The 18S rDNA, psbA, and rbcL genes were used to confirm the identification of Corallina pilulifera. Measuring viability using triphenyl tetrazolium chloride showed highly viability from December to January. Cultural conditions of 16 C, 16 h light:8 h dark cycle, and 40 mu E m(-2) s(-1) light intensity were optimal for maintaining the viability of the coralline alga for up to three days. The fatty acids included 31.4% omega-3 eicosapentaenoic acid. Scanning electron microscopy of the surface structure revealed unique round wells about 7.9 +/- 1.3 mu m in diameter. The coralline alga, preventing fleshy seaweeds, may be used as a potential template for the creation of new environmentally friendly biomimetic antifouling material against the attachment of soft foulants, especially micro- and macroalgae.X111Ysciescopu
Understanding Solidification of Polythiophene Thin Films during Spin-Coating: Effects of Spin-Coating Time and Processing Additives
Spin-coating has been used extensively in the fabrication of electronic devices; however, the effects of the processing parameters have not been fully explored. Here, we systematically characterize the effects of the spin-coating time on the microstructure evolution during semiconducting polymer solidification in an effort to establish the relationship between this parameter and the performances of the resulting polymer field-effect transistors (FETs). We found that a short spin-coating time of a few seconds dramatically improve the morphology and molecular order in a conjugated polymer thin film because the p-p stacking structures formed by the polymer molecules grow slowly and with a greater degree of order due to the residual solvent present in the wet film. The improved ordering is correlated with improved charge carrier transport in the FETs prepared from these films. We also demonstrated the effects of various processing additives on the resulting FET characteristics as well as on the film drying behavior during spin-coating. The physical properties of the additives are found to affect the film drying process and the resulting device performance.113427Ysciescopu
Adsorption-induced conversion of the carbon nanotube field effect transistor from ambipolar to unipolar behavior
We investigate ambipolar to unipolar transition by the effect of ambient air on the carbon nanotube field-effect transistor. A unipolar transport property of the double-walled nanotube field-effect transistor and its conversion from ambipolar behavior are observed. We suggest that adsorptions of oxygen molecules, whose lowest-unoccupied-molecular-orbital state is around the midgap of the carbon nanotube, could suppress the electron channel formation and, consequently, result in the unipolar transport behavior.open343
Chemical ordering in PtNi nanocrystals
We investigated the chemical ordering in PtNi nanocrystals fabricated on sapphire substrate using in-situ synchrotron X-ray scattering. Nanocrystals with composition close to 1:1 were ordered in the tetragonal L1(0) structure at low temperatures. The transition to disordered FCC structure occurred at around 640 degrees C and substantial hysteresis of about 50 K was observed. Nanocrystals of smaller sizes fabricated under the same conditions were Ni rich and ordered into Cu3Au type L1(2) structure. Significantly higher degree of chemical ordering was observed in L1(2) structure than in L1(0) structure. (C) 2016 Elsevier B.V. All rights reserved.1144Ysciescopu
Response to imatinib rechallenge in a patient with a recurrent gastrointestinal stromal tumor after adjuvant therapy: a case report
<p>Abstract</p> <p>Introduction</p> <p>Adjuvant imatinib improves recurrence-free survival of patients following resection of primary KIT-positive gastrointestinal stromal tumors. However, it is unknown whether patients who previously received adjuvant imatinib therapy will respond to imatinib rechallenge as treatment for recurrent disease. Here we present the first report documenting the benefits of imatinib rechallenge in a patient previously exposed to imatinib during adjuvant treatment.</p> <p>Case presentation</p> <p>A 51-year-old Asian woman with a wedge-resected primary gastric gastrointestinal stromal tumor at high risk of relapse underwent two years of adjuvant treatment with imatinib. Only 10 months after the completion of adjuvant imatinib treatment, a computed tomography scan revealed gastrointestinal stromal tumor recurrence in this patient, with multiple peritoneal nodules in the upper abdomen being detected. Our patient was rechallenged with imatinib 400 mg/day and had a partial response after one month of treatment. Imatinib rechallenge was well tolerated by our patient; the only adverse events she experienced were grade 1 edema, anemia and fatigue. Our patient maintained a partial response two years and six months after the imatinib rechallenge. However, computed tomography scans three months later showed that our patient had disease progression.</p> <p>Conclusions</p> <p>This case report demonstrates that a patient with a gastrointestinal stromal tumor who had previously received adjuvant imatinib therapy responded to imatinib rechallenge as treatment for her recurrent disease. These results indicate that imatinib sensitivity can be maintained in a patient with previous exposure to adjuvant imatinib therapy.</p
Effects of adding natural sounds to urban noises on the perceived loudness of noise and soundscape quality
Introducing pleasant natural sounds to mask urban noises is an important soundscape design strategy to improve acoustic comfort. This study investigates the effects of signal-to-noise ratio (SNR) between natural sounds (signal) and the target noises (noise) and their temporal characteristics on the perceived loudness of noise (PLN) and overall soundscape quality (OSQ) through a laboratory experiment. Two types of urban noise sources (hydraulic breaker and traffic noises) were set to A-weighted equivalent sound pressure levels (SPL) of 55, 65, and 75 dB and then augmented with two types of natural sounds (birdsong and stream), across a range of SNRs. Each acoustic stimulus was a combination of noise and natural sound at SNRs from −6 to 6 dB. Averaged across all cases, the subjective assessment of PLN showed that augmenting urban noise separately with the two natural sounds reduced the PLN by 17.9%, with no significant differences found between the birdsong and stream sounds. Adding natural sounds increased the OSQ by on average 18.3% across the cases, but their effects gradually decreased as the noise level increased. The OSQ of the birdsong and stream sounds were similar for traffic noise, whereas the stream sound was rated higher than the birdsong for the breaker noise. The results suggest that increasing the dissimilarity in temporal structure between the target noise and natural sounds could enhance the soundscape quality. Appropriate SNRs were explored considering both PLN and OSQ. The results showed that the SNR of −6 dB was desirable when the A-weighted SPL of the noise rose to 75 dB
Effects of contexts in urban residential areas on the pleasantness and appropriateness of natural sounds
Before introducing natural sounds to potentially improve the soundscape quality, it is important to understand how key contextual factors (i.e. expected activities and audio-visual congruency) affect the soundscape in a given location. In this study, the perception of eight natural sounds (i.e. 4 birdsongs, 4 water sounds) at five urban recreational areas under the constant influence of road traffic was explored subjectively under three laboratory settings: visual-only, audio-only, and audio-visual. Firstly, expected socio-recreational activities of each location were determined in the visual-only setting. Subsequently, participants assessed the pleasantness and appropriateness of the soundscape at each site, for each of the eight natural sounds augmented to the same road traffic noise, in both audio-only and audio-visual settings. Interestingly, it was found that the expected activities in each location did not significantly affect natural sound perception, whereas audio-visual congruency of the locations significantly affected the pleasantness and appropriateness of the natural sounds. Particularly, the pleasantness and appropriateness decreased for water sounds when water features were not visually present. In contrast, perception with birdsongs was unaffected by their visibility likely due to the presence of vegetation. Hence, audio-visual coherence is central to the perception of natural sounds in outdoor spaces
A mixed-reality approach to soundscape assessment of outdoor urban environments augmented with natural sounds
To investigate the effect of augmenting natural sounds in noisy environments, an in-situ experiment was conducted using a mixed-reality head-mounted display (MR HMD). Two outdoor locations close to an expressway were selected for the experiment. A natural sound (birdsong or stream) along with a hologram (sparrow/fountain or loudspeaker) was projected through the MR HMD. Participants were asked to adjust the natural sound levels to their preferred level under ambient traffic noise conditions at each location. Participants also assessed the perceived loudness of traffic (PLN) and overall soundscape quality (OSQ) in conditions with and without the augmented natural sounds. The results showed that both natural sounds significantly reduced the PLN and enhanced the OSQ. No significant differences in subjective responses were found between the loudspeaker and visual representations of the natural sound source as holograms. Analysis on the preferred signal-to-noise ratio (SNR), i.e. ratio of natural sound to traffic levels, indicated a strong negative correlation between the preferred SNRs and ambient traffic noise levels. Overall, the preferred SNR of the birdsong was significantly higher than that of the water sound. Among the acoustic parameters tested, the A-weighted traffic noise level was the strongest predictor for the preferred SNR of both the birdsong and water sound. However, the correlation for the water sound was relatively higher than the birdsong. This was due to the larger variance in the subjective evaluation for the birdsong
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