Search

This paper presents a method to invert the two-dimensional distribution of a temperature and volume concentration of soot particles from color images. By using numerical simulation, the temperature field and particle volume-concentration field of a non-uniform soot flame are simultaneously reconstructed using the wide-response spectrum of a color CCD camera without adding monochromatic filters. The influence of number of cameras, error of camera position angle, measurement noise and different reconstruction algorithms on measurement accuracy are analyzed. The numerical-simulation results demonstrate that camera-position angle errors play a crucial role in the reconstruction accuracy. In addition, increasing the number of cameras can improve the reconstruction result accuracy. Compared with the least squares algorithm, the Tikhonov-regularization algorithm has a stronger anti-noise ability and can resist 39 dB of noise. The conclusions obtained in this paper are helpful to guide following experimental studies. [ABSTRACT FROM AUTHOR]

As an economically important flatfish in Asia, Japanese flounder is threatened by continuously rising temperatures due to global warming. To understand the molecular responses of this species to temperature stress, adult Japanese flounder individuals were treated with two kinds of heat stress—a gradual temperature rise (GTR) and an abrupt temperature rise (ATR)—in aquaria under experimental conditions. Changes in histopathology, programmed cell death levels and the oxidative stress status of gills were investigated. Histopathology showed that the damage caused by ATR stress was more serious. TUNEL signals confirmed this result, showing more programmed cell death in the ATR group. In addition, reactive oxygen species (ROS) levels and the 8-O-hDG contents of both the GTR and ATR groups increased significantly, and the total superoxide dismutase (T-SOD) activities and total antioxidant capacity (T-AOC) levels decreased in the two stressed groups, which showed damage to antioxidant systems. Meanwhile, RNA-seq was utilized to illustrate the molecular mechanisms underyling gill damage. Compared to the control group of 18 °C, 507 differentially expressed genes (DEGs) were screened in the GTR group; 341 were up-regulated and 166 were down-regulated, and pathway enrichment analysis indicated that they were involved in regulation and adaptation, including chaperone and folding catalyst pathways, the mitogen-activated protein kinase signaling (MAPK) pathway and DNA replication protein pathways. After ATR stress, 1070 DEGs were identified, 627 were up-regulated and 423 were down-regulated, and most DEGs were involved in chaperone and folding catalyst and DNA-related pathways, such as DNA replication proteins and nucleotide excision repair. The annotation of DEGs showed the great importance of heat shock proteins (HSPs) in protecting Japanese flounder from heat stress injury; 12 hsp genes were found after GTR, while 5 hsp genes were found after ATR. In summary, our study records gill dysfunction after heat stress, with different response patterns observed in the two experimental designs; chaperones were activated to defend heat stress after GTR, while replication was almost abandoned due to the severe damage consequent on ATR stress. [ABSTRACT FROM AUTHOR]