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Open access

Dong Zhou, Hui Zhang and Peiqing Ye

Abstract

Background. Penumbra characteristics play a significant role in dose delivery accuracy for radiation therapy. For treatment planning, penumbra width and radiation field offset strongly influence target dose conformity and organ at risk sparing.

Methods. In this study, we present an analytical and numerical approach for evaluation of the rounded leaf end effect on penumbra characteristics. Based on the rule of half-value layer, algorithms for leaf position calculation and radiation field offset correction were developed, which were advantageous particularly in dealing with large radius leaf end. Computer simulation was performed based on the Monte Carlo codes of EGSnrc/BEAMnrc, with groups of leaf end radii and source sizes. Data processing technique of curve fitting was employed for deriving penumbra width and radiation field offset.

Results. Results showed that penumbra width increased with source size. Penumbra width curves for large radius leaf end were U-shaped. This observation was probably related to the fact that radiation beams penetrated through the proximal and distal leaf sides. In contrast, source size had negligible impact on radiation field offset. Radiation field offsets were found to be constant both for analytical method and numerical simulation. However, the overall resulting values of radiation field offset obtained by analytical method were slightly smaller compared with Monte Carlo simulation.

Conclusions. The method we proposed could provide insight into the investigation of rounded leaf end effects on penumbra characteristics. Penumbra width and radiation field offset calibration should be carefully performed to commission multileaf collimator for intensity modulated radiotherapy.

Open access

Lei Zhang, Zhiwei Ye, Jun Tang, Dingyi Hao and Cun Zhang

Abstract

As a kind of associated geological gas, coalbed methane (CBM) is mainly adsorbed in the coal seam. The coal-methane adsorption phenomenon can be described by Langmuir monolayer adsorptio n model, BET multilayer adsorption model and the Theory of Volume Filling of Micropore (TVFM), whereas the binary gas adsorption phenomenon can be described by the extended Langmuir Model. For the CBM in the low permeability coal seam, the amount of gas released by direct drainage is relatively limited, which cannot eliminate the gas explosion and outburst hazards. Gas injection is an effective method to promote methane drainage. In this paper, the free desorption and nitrogen injection displacement experiments are comparatively analyzed, which allows verifying the effectiveness of nitrogen injection’s enhancement to gas drainage. The experiment of injecting nitrogen gas into the coal body shows that the coal fracture can be maintained or expanded by the injected gas pressure so that more methane can be released. The nitrogen injection has a higher time efficiency than that of free desorption as well. The displacement ratio of N2/CH4 is in the range of 1-3. Both the injection pressure and confining pressure affect the displacement ratio. The analysis of the desorbed gas components shows that the relationship between the methane component and gas flooding time is an “inverted S” shape curve, and the appropriate time for the methane collection can be inferred by the time interval of the rapid decline of the curve.

Open access

Jing Zhang, Shu-Ming Zhou, Li Xu, Wei Wu and Xiucai Ye

Abstract

The connected dominating set (CDS) has become a well-known approach for constructing a virtual backbone in wireless sensor networks. Then traffic can forwarded by the virtual backbone and other nodes turn off their radios to save energy. Furthermore, a smaller CDS incurs fewer interference problems. However, constructing a minimum CDS is an NP-hard problem, and thus most researchers concentrate on how to derive approximate algorithms. In this paper, a novel algorithm based on the induced tree of the crossed cube (ITCC) is presented. The ITCC is to find a maximal independent set (MIS), which is based on building an induced tree of the crossed cube network, and then to connect the MIS nodes to form a CDS. The priority of an induced tree is determined according to a new parameter, the degree of the node in the square of a graph. This paper presents the proof that the ITCC generates a CDS with a lower approximation ratio. Furthermore, it is proved that the cardinality of the induced trees is a Fibonacci sequence, and an upper bound to the number of the dominating set is established. The simulations show that the algorithm provides the smallest CDS size compared with some other traditional algorithms.

Open access

Jing-guang Qian, Yang Su, Ya-wei Song, Ye Qiang and Songning Zhang

A Comparison of a Multi-body Model and 3D Kinematics and EMG of Double-leg Circle on Pommel Horse

The purpose of this study was to establish a multi-segment dynamic model in the LifeMOD to examine kinematics of the center of mass and foot, and muscle forces of selected upper extremity muslces during a double-leg circle (DLC) movement on pommel horse in gymnastics and compared with three-dimensional kinematics of the movement and surface electromyographic (sEMG) activity of the muscles. The DLC movement of one elite male gymnast was collected. The three-dimensional (3D) data was imported in the Lifemod to create a full-body human model. A 16-Channel surface electromyography system was used to collect sEMG signals of middle deltoid, biceps brachii, triceps brachii, latissimusdorsi, and pectoralis major. The 3D center of mass and foot displacement showed a good match with the computer simulated results. The muscle force estimations from the model during the four DLC phases were also generally supported by the integrated sEMG results, suggesting that the model was valid. A potential application of this model is to help identify shortcomings of athletes and help establish appropriate training plans errors in the DLC technique during training.

Open access

Dan-Dan Zhang, Pi Luo, Ying Chen, Zheng-Feng Wang, Wan-Hui Ye and Hong-Lin Cao

Abstract

Engelhardia roxburghiana is a common half evergreen tree with a wide distribution in southeast Asia. Despite its ecological and pharmaceutical values, its genetic diversity is poorly studied. Our objective was to develop nuclear microsatellite markers to investigate the level of genetic diversity within and among populations in the future. Using the microsatellite-enriched library and PCR-based screening method, 12 microsatellite markers were developed and showed polymorphism in a population. The number of alleles per locus for these 12 microsatellites ranged from four to 15. The observed and expected heterozygosities ranged from 0.358 to 0.897 and from 0.369 to 0.886, respectively. The developed microsatellites will be useful for studying genetic diversity and population structure in E. roxburghiana.

Open access

Zhitong Bing, Guanghui Yang, Yanan Zhang, Fengling Wang, Caiyong Ye, Jintu Sun, Guangming Zhou and Lei Yang

Abstract

Background. Carbon ion therapy may be better against cancer than the effects of a photon beam. To investigate a biological advantage of carbon ion beam over X-rays, the radioresistant cell line HeLa cells were used. Radiationinduced changes in the biological processes were investigated post-irradiation at 1 h by a clinically relevant radiation dose (2 Gy X-ray and 2 Gy carbon beam). The differential expression proteins were collected for analysing biological effects.

Materials and methods. The radioresistant cell line Hela cells were used. In our study, the stable isotope labelling with amino acids (SILAC) method coupled with 2D-LC-LTQ Orbitrap mass spectrometry was applied to identity and quantify the differentially expressed proteins after irradiation. The Western blotting experiment was used to validate the data.

Results. A total of 123 and 155 significantly changed proteins were evaluated with treatment of 2 Gy carbon and X-rays after radiation 1 h, respectively. These deregulated proteins were found to be mainly involved in several kinds of metabolism processes through Gene Ontology (GO) enrichment analysis. The two groups perform different response to different types of irradiation.

Conclusions. The radioresistance of the cancer cells treated with 2 Gy X-rays irradiation may be largely due to glycolysis enhancement, while the greater killing effect of 2 Gy carbon may be due to unchanged glycolysis and decreased amino acid metabolism.

Open access

Xiao-Dong Zhang, Yi-Fang Feng, Xu Zhang, Mi Tian, Tao Wu, Peng-Fei Ye, Wei Zhang, Yue-Yun Ding, Zong-Jun Yin and Ming-Xing Chu

Abstract

To justify the function of miRNAs in reproductive regulation in swine, the expression of miR-145, miR-429 and their related genes were studied in reproductive tissues of sows. Wannan black pig and Yorkshire pigs with extremely high (n=6) and low (n=6) litter size were sampled, and real-time quantitative PCR (qPCR) was performed on tissue samples from ovaries, uterus, oviduct, hypothalamus, and pituitary. The results indicated that miR-145, miR-429, and zinc finger E-box binding homeobox 1 gene (ZEB1) were expressed significantly different in Wannan black pig and Yorkshire pigs. In pigs with different fecundity, miR-145 in the uterus was expressed significantly lower in pigs with high litter size, than in pigs with low litter size. The miR-429 expression in the oviduct and pituitary of pigs with high litter size was significantly higher compared with tissues sampled from pigs with low litter size. The ZEB1 expression in the pituitary was lower in pigs with high litter size in comparison to pigs with low litter size, while luteinizing hormone beta subunit (LHβ) showed the opposite pattern of expression. In conclusion, miR-145 and miR-429 were differently expressed in pigs with high and low litter size and might have a role in affecting litter size of sows.

Open access

Hong-Yu Niu, Wan-Hui Ye, Zheng-Feng Wang, Ying Chen, Hong-Lin Cao, Lin-Fang Wu and Zhang-Ming Wang

Abstract

Schima superba is a common dominant tree species in evergreen broad-leaved forest in subtropical China. Despite its multiple usages in wood industry, reforestation and traditional Chinese medicine, its genetic diversity is poorly studied. To help studying its genetic diversity and structure in the future, after microsatellite enrichment and screening, we identified 16 microsatellites in S. superba. These markers showed polymorphism in three populations. The number of alleles per locus ranged from 3 to 32 with a mean of 14. Within populations, the observed and unbiased expected heterozygosities ranged from 0.048 to 0.926 and from 0.048 to 0.949, respectively. The newly developed 16 microsatellites will be useful for investigating the genetic diversity and structure from large scale patterns to fine-scale structures in this species.

Open access

Hong Du, Jing Li, Hai-tao Yu, Wei Jiang, Ye Zhang, Jun-ning Wang, Ping-zhong Wang and Xue-fan Bai

Abstract

Objective To observe the application of continuous renal replacement therapy (CRRT) and heparin anticoagulation in patients with HFRS, and to explore a more suitable anticoagulant strategy.

Methods Eighty-five severe-type patients (severe group) and 71 critical-type patients (critical group) were enrolled in this study. The frequency of CRRT was compared between the two groups; the frequency of CRRT treated with and without heparin anticoagulation and the frequency of hemorrhage and channel blood clotting induced by the two anticoagulant strategies were observed.

Results The frequency of CRRT in the critical group was higher than that in the severe group (P < 0.001). The frequency of CRRT initiated during the overlapping phases in the critical group was significantly higher than that of the severe group (P = 0.032). The total times of CRRT was 103, and 70 of them were treated with heparin anticoagulation. The frequencies of hemorrhage induced by heparin anticoagulation and no heparinization were 16 and 0, respectively, and the frequencies of channel blood clotting were 2 and 4, respectively.

Conclusions CRRT has been used extensively in the critical-type patients with HFRS. The heparin anticoagulation and no anticoagulant strategies should be used more rationally in patients treated with CRRT, according to the clinical characteristics of the disease.

Open access

Y. Zeng, W. Ye, L. Yang, Y. Huang, K. Zhao, Z. Zhang, H. Liang and J. Kerns

Abstract

Studies were conducted to characterize morphological and molecular profiles of two isolates of Paratrichodorus porosus (SZ1 and SZ2) which were recovered from Acacia mangium in Tianxinshan and Gleichenia linearis in Yangmeikeng environmental monitoring sites in Shenzhen, China, respectively. Analysis of morphometric, morphological and molecular characters revealed these two Shenzhen isolates are identical to P. porosus. Measurements of both study isolates lie within the ranges for P. porosus. It is typologically characterized by possessing a clearly swollen body cuticle after fixation, an onchiostyle ventrally curved, 46–58 μm long, a pharyngeal bulb usually with a well developed anterior-dorsal intestinal overlap, a secretoryexcretory pore opening between the nerve ring and anterior end of pharyngeal bulb, 90–110 μm from the anterior end, a reproductive system with didelphic, amphidelphic, without spermathecae, a pore-like vulva in ventral view and occupying 52.0 %–59.5 % of total body length from anterior end, a short and barrel-shaped vagina with small sclerotizations, a pair of ventromedian advulvar body pores located prevulvar and postvulvar, a rounded tail and a subterminal anus in females. The sequence analysis based on partial rDNA 18S gene and 28S D2/D3 expansion segment confirm its identity as P. porosus. This is the first report of P. porosus associated with A. mangium and G. linearis.