The moose, purine degradation, and environmental adaptation

It is accepted that allantoin is the end-product of purine degradation in mammals, except that uricase activity has been lost during the evolution of humans in which uric acid protects the brain from oxidative damage. However, we have found that the moose Alces americanus excretes extremely low urinary concentrations of allantoin and high concentrations of uric acid very similar to those of humans. Exposure to extreme cold is known to cause oxidative damage, and we suggest that the retention of uric acid by the moose represents an adaptation enabling the species to survive at high latitudes.Weiqi Zhang, Philip Stott, Minghai Zhan

Survey on the Overwintering of Syrphids in Changbai Mountains and Experiments on Artificial Protection of the Overwintering Syrphid Flies

Originating text in Chinese.Citation: Gao, Junfeng, Zhang, Guangxin, Qin, Yongchun, Yu, Kai, Li, Minghai, Qin, Yi. (1993). Survey on the Overwintering of Syrphids in Changbai Mountains and Experiments on Artificial Protection of the Overwintering Syrphid Flies. Chinese Journal of Biological Control, 9(3), 142-144

Characterization of vascular endothelial progenitor cells from chicken bone marrow

BACKGROUND: Endothelial progenitor cells (EPC) are a type of stem cell used in the treatment of atherosclerosis, vascular injury and regeneration. At present, most of the EPCs studied are from human and mouse, whereas the study of poultry-derived EPCs has rarely been reported. In the present study, chicken bone marrow-derived EPCs were isolated and studied at the cellular level using immunofluorescence and RT-PCR. RESULTS: We found that the majority of chicken EPCs were spindle shaped. The growth-curves of chicken EPCs at passages (P) 1, -5 and -9 were typically “S”-shaped. The viability of chicken EPCs, before and after cryopreservation was 92.2% and 81.1%, respectively. Thus, cryopreservation had no obvious effects on the viability of chicken EPCs. Dil-ac-LDL and FITC-UAE-1 uptake assays and immunofluorescent detection of the cell surface markers CD34, CD133, VEGFR-2 confirmed that the cells obtained in vitro were EPCs. Observation of endothelial-specific Weibel-Palade bodies using transmission electron microscopy further confirmed that the cells were of endothelial lineage. In addition, chicken EPCs differentiated into endothelial cells and smooth muscle cells upon induction with VEGF and PDGF-BB, respectively, suggesting that the chicken EPCs retained multipotency in vitro. CONCLUSIONS: These results suggest that chicken EPCs not only have strong self-renewal capacity, but also the potential to differentiate into endothelial and smooth muscle cells. This research provides theoretical basis and experimental evidence for potential therapeutic application of endothelial progenitor cells in the treatment of atherosclerosis, vascular injury and diabetic complications

A study on genetic divergence of the Red squirrel Sciurus vulgaris (Rodentia: Mammalia) from six regions in Eurasia: based on cytochrome b complete sequences

Cytochrome b complete sequences (1140 bp) of Sciurus vulgaris from four regions in continental Asia (Korea, northeastern China, far-eastern Russia, and Mongolia) were obtained and analysed with corresponding complete and partial (359 bp) haplotypes of S. vulgaris, obtained from GenBank. These sequences were used to compare our and previous results from partial sequences and to examine population differentiation of S. vulgaris in Eurasia by using complete sequences and by using more numerous specimens. Based on partial sequences from ten Eurasian regions (the four regions in Asia, Japan, Portugal, western China, Russia, and northern and southern Italy), we found that S. vulgaris is composed of two clades (a minor one from southern Italy and a major one from other Eurasian regions). We considered that our results are more conclusive than previous results by other researchers, performed without using haplotypes from Korea, Mongolia, and far-eastern Russia and detected three clades (southern Italy, Russia, and other Eurasia) or two clades with one distinguishable haplotype. Moreover, we found that our results from partial sequences are less informative than those from complete sequences, indicating that cytochrome b complete sequences from Eurasia are needed in order to examine population structure of S. vulgaris. Finally, in this study on population differentiation from cytochrome b complete sequence analyses, we found that genetic divergence of six Eurasian populations, including the four Asian populations, is low, and that our results do not support the current subspecies classification, recognizing 23 subspecies

Joint Sensor Selection and Power Allocation Algorithm for Multiple-Target Tracking of Unmanned Cluster Based on Fuzzy Logic Reasoning

The unmanned aerial vehicle (UAV) cluster is gradually attracting more attention, which takes advantage over a traditional single manned platform. Because the size of the UAV platform limits the transmitting power of its own radar, how to reduce the transmitting power while meeting the detection accuracy is necessary. Aim at multiple-target tracking (MTT), a joint radar node selection and power allocation algorithm for radar networks is proposed. The algorithm first uses fuzzy logic reasoning (FLR) to obtain the priority of targets to radars, and designs a radar clustering algorithm based on the priority to form several subradar networks. The radar clustering algorithm simplifies the problem of multiple-radar tracking multiple-target into several problems of multiple-radar tracking a single target, which avoids complex calculations caused by multiple variables in the objective function of joint radar node selection and power allocation model. Considering the uncertainty of the target RCS in practice, the chance-constraint programming (CCP) is used to balance power resource and tracking accuracy. Through the joint radar node selection and power allocation algorithm, the radar networks can use less power resource to achieve a given tracking performance, which is more suitable for working on drone platforms. Finally, the simulation proves the effectiveness of the algorithm

Numerical Study of Natural Convection Heat Transfer in a Porous Annulus Filled with a Cu-Nanofluid

Natural convection heat transfer in a porous annulus filled with a Cu nanofluid has been investigated numerically. The Darcy–Brinkman and the energy transport equations are employed to describe the nanofluid motion and the heat transfer in the porous medium. Numerical results including the isotherms, streamlines, and heat transfer rate are obtained under the following parameters: Brownian motion, Rayleigh number (103–105), Darcy number (10−4–10−2), nanoparticle volume fraction (0.01–0.09), nanoparticle diameter (10–90 nm), porosity (0.1–0.9), and radius ratio (1.1–10). Results show that Brownian motion should be considered. The nanoparticle volume fraction has a positive effect on the heat transfer rate, especially with high Rayleigh number and Darcy number, while the nanoparticle diameter has an inverse influence. The heat transfer rate is enhanced with the increase of porosity. The radius ratio has a significant influence on the isotherms, streamlines, and heat transfer rate, and the rate is greatly enhanced with the increase of radius ratio