Effect of changes in lung physical properties on microwave ablation zone during respiration

Defu Yang,Miao Cao 대한의용생체공학회 2020 Biomedical Engineering Letters (BMEL) Vol.10 No.2

Microwave ablation is a promising minimally invasive treatment for cancer. However, due to the respiratory movement ofthe lungs, it is very diffi cult to accurately predict and control the microwave ablation zone. Therefore, the infl uence of thechanges of the physical parameters of the respiratory process on the microwave ablation zone is studied. Firstly, based onthe 4D-CT describing the respiratory process of the lungs, all the image data are from 100 non-small cell lung cancer radiotherapypatients (50 males and 50 females, average 58 years, range 55–61 years). According to the theory of porous media,the change of the eff ective thermal conductivity of the lung tissue during the breathing process is obtained. The eff ectivethermal conductivity of the lung parenchyma during respiration varies from 0.16 to 0.20 W/m °C, with the lowest vale at theend of inspiration and the highest at the end of expiration. The transient problems during microwave ablation of pulmonarytissue are analyzed by fi nite element method. The changes of relative permittivity, conductivity and density changes duringthe breathing process are also considered. The results show that the microwave ablation zone is signifi cantly larger underdynamic physical parameters. At the end of expiration, when the tissue parameter is set to constant, the ablation lesion areais more concentrated around the tip and slot of the antenna, and the backward heating eff ect is smaller, Ablation volume wassuperior in nonventilated lungs. Therefore, single-lung ventilation can be considered during pulmonary ablation to reducethe impact of breathing on the ablation area. These fi ndings can be useful to further our understanding the MWA and holdpromise towards achieving successful treatment objective as well as enhanced therapeutic output via improved treatmentplanning and strategy. This study provides the basis for clinical pulmonary ablation and can also be used as a preoperativeplan to provide guidance to physicians.

Carcass Fat-free Lean Gain of Chinese Growing-finishing Pigs Reared on Commercial Farms

Yang, Libin,Li, Defa,Qiao, Shiyan,Gong, Limin,Zhang, Defu Asian Australasian Association of Animal Productio 2002 Animal Bioscience Vol.15 No.10

Five regions and 258 pigs were selected for this study: North (Beijing), Central (Wuhan), South (Guangzhou), Southwest (Chongqing), Northeast (Harbin). Five typical genetics of growing-finishing pig were selected: Landrace${\times}$Large White${\times}$Beijing Black, Duroc${\times}$Landrace${\times}$Large White, Duroc${\times}$Large White${\times}$Landrace, Landrace${\times}$Rongchang, Landrace${\times}$Harbin White, respectively at each sites. The basal diet was a corn-soybean meal containing sufficient nutrients to meet requirements. Carcass fat-free lean gain was determined by dissecting and analyzing chemical composition of the carcass. Cubic function fitted lean moistures to live weights better than other functions. Exponential function fitted lean lipids to live weights equally to allometric function. Carcass fat-free lean gain of Duroc${\times}$Large White${\times}$Landrace, Landrace${\times}$Large White${\times}$Beijing Black, Duroc${\times}$Landrace${\times}$Large White, Landrace${\times}$Harbin White, Landrace${\times}$Rongchang from 20 to 100 kg of average body weight was 259 g/d, 261 g/d, 311 g/d, 220 g/d, 200 g/d, respectively. All are lower than intermediate fat-free lean gain in NRC (1998).

Effects of Replacing Corn with Brown Rice or Brown Rice with Enzyme on Growth Performance and Nutrient Digestibility in Growing Pigs

Zhang, Defu,Li, Defa,Piao, X.S.,Han, In K.,Yang, Chul J.,Shin, In S.,Dai, J.G.,Li, J.B. Asian Australasian Association of Animal Productio 2002 Animal Bioscience Vol.15 No.9

A 4 week experiment was designed to study the effects of replacing corn with Chinese brown rice or adding different amylase in brown rice basal diet on growth performance and apparent fecal digestibilities of nutrients in growing pigs. One hundred and eight cross-bred pigs (Duroc${\times}$Landrace${\times}$Large White), weighing an average of $18.35{\pm}0.12kg$, were randomly assigned to 6 treatments with 6 replications per treatment. Diet in treatment 1 was corn-soybean meal basal diet, and in treatment 2, 3 and 4, corn was replaced by brown rice on rates of 33.3%, 66.7% and 100% respectively on the basis of treatment 1. And diets in treatment 5 and 6 were similar to treatment 4 except two kinds of amylases, glucoamylase and ${\alpha}$-amylase, were added respectively. The brown rice used in this experiment was husked from one kind of early, long grain, non-glutinous rice (ELGNR, indica rice) in southern China. The results indicated that there was a slight improvement in growth performance of pigs in brown rice treatments (p>0.05). The blood urea nitrogen value in treatment 2 was lower than that in treatment 1 (p<0.05). The differences of apparent fecal digestibilities of most nutrients were significant (p<0.05) except CP. Digestibilities of GE, OM and DM in treatment 4 were the best and digestibility of crude fat in treatment 5 appeared best (p<0.05). Contrast results between treatment 1 and treatment 2 to 4 indicated that the digestibility of GE, OM and DM increased significantly with the replacing rates of brown rice (p<0.05). Contrast results between treatment 4 and 5 indicated that adding glucoamylase in brown rice diet increased growth performance slightly (p>0.05) but not for digestibilities. This experiment shows a positive effect of brown rice on growth performance, especially on nutrient digestibility.

Sliding Mode Resilient Control and Application Based on Intermediate Variable Observer in Smart Grid

Jian Li,Defu Yang,Qingyu Su 제어·로봇·시스템학회 2023 International Journal of Control, Automation, and Vol.21 No.6

This paper focuses on the reliable operation of cyber-physical systems (CPS) under malicious attacks. First of all, according to the characteristics of false data injection (FDI) attacks and dynamic load altering (DLA) attacks, a type of power CPS system model with process attacks is established. Secondly, a state estimation method and security control strategy are designed, respectively. Specifically, 1) In order to estimate the system state and reconstruct the attack signal, an intermediate variable observer is designed, 2) An integral sliding mode control strategy is proposed by using the reconstructed attack information and system error information to automatically eliminate the impact of the attack on the power CPS system. Finally, using the digital simulation and hardwarein-the-loop simulation platforms constructed by StarSim, a three-generator and six-bus power system is used as an example, the effectiveness of the proposed control strategy in theory and practical application is verified.

Effect of oxidative modification of activated carbon for the adsorption behavior of nicotine

Kewu Pi,Min Xia,Pan Wu,Meichen Yang,Shuyu Chen,Defu Liu,Andrea R. Gerson 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.31 No.-

The adsorption of nicotine onto activated (AC) and AC modified (MAC, by contact with ammoniumpersulfate) can be described well using the Langmuir model with maximum adsorption capacities of 552and 640 mg g 1, respectively. Nicotine has high ‘hardness’ and appears to adsorb most readily on theincreased concentration of ‘hard’ MAC edge functional groups. Adsorption is shown to be exothermic;with enthalpy of 10 and 16 kJ mol 1 for AC and MAC, respectively. The negative free energy andpositive entropy of adsorption indicate a spontaneous process and a strong affinity between aqueousnicotine and AC or MAC.

Some Factors Affecting Freezing of Boar Semen in 5 ml Maxi-straws

Dai, J.J.,Wu, C.F.,Zhang, Defu,Yin, F.Z.,Zhang, T.Y.,Liu, D.,Wu, H.L.,Li, L.L.,Yang, S.T.,Wang, L. Asian Australasian Association of Animal Productio 2009 Animal Bioscience Vol.22 No.4

A series of experiments were conducted to determine the suitable freezing and thawing temperatures for the freezing of boar semen in 5 ml maxi-straws. The ultrastructure, in vitro fertilization (IVF) and artificial insemination (AI) of frozen-thawed semen were also be evaluated. The 5 cm freezing height gave the best results not only in post-thaw motility rate (54.00%), but also in normal acrosome morphology rate (NAR) (80.23%). There was no significant difference in the post-thaw motility between different thawing temperatures and corresponding thawing times (p>0.05); the group of $52^{\circ}C$ and 25 s gave the highest motility rate (45.00%). As a whole, not only from the motility but also the NAR, thawing at $42^{\circ}C$ was better than the other two treatments. In the freezing packages, 5 ml maxi-straw gave a little lower mobility (40%), viability rate (49.58%), plasma membrane integrity rate (53.91%) and NAR (52.65%) than the 0.25 ml straw, but there was no significant difference between the two straw volumes (p>0.05). The IVF capacity of frozen-thawed semen in this experiment was similar to fresh semen. From ultrastructure observation, the main damage to boar spermatozoa after freezing was seen in the acrosome, such as swelling and formation of vesicles. After AI in recipient Shanghai White sows, frozen-thawed semen from 5 ml maxi-straws and pellets produced 72.2% and 80% conception rate and 7.8 and 8 litter sizes, respectively, and there was no significant difference between the 5 ml maxi-straw and the pellet (p>0.05).