A Study of Urodynamic Parameters at Different Bladder Filling Stages for Predicting Upper Urinary Tract Dilatation

Lei Lyu,Ya Xiong Yao,Er Peng Liu,Yan Ping Zhang,Hui Jie Hu,Feng Ping Ji,Qing Song Pu,Xing Huan Yang,Qing Wei Wang,Yan Wang,Jian Guo Wen 대한배뇨장애요실금학회 2022 International Neurourology Journal Vol.26 No.1

Purpose: To identify more accurate predictors of upper urinary tract dilatation (UUTD) in neurogenic bladder (NB) children, we studied the relationship among urodynamic parameters at different bladder filling stages, detrusor leak point pressure (DLPP) and UUTD. Methods: A total of 158 children (3–16 years) with NB were included and then divided into 2 groups according to whether their NB diagnosis was complicated with UUTD: the UUTD group (39 patients) and those without UUTD group (control group, 119 patients). The bladder filling phase was divided into 3 equal parts: the early, middle, and end filling stages. The bladder compliance (BC) and detrusor pressure (△Pdet) at each phase and DLPP at the end filling stage were recorded. Results: A BC<8 mL/cm H2O both in the middle and end stages is more specific than a BC<9 mL/cm H2O in the end stage (72%, 73%, vs. 66%), and △Pdet >8 cm H2O in the early stage, 20 cm H2O in the middle stage and 25 cm H2O in the end stage are more sensitive than △Pdet >40 cm H2O in the end stage (82%, 85%, 85%, vs. 49%). A DLPP cutoff value of 20 cm H2O showed higher sensitivity for predicting UUTD than 40 cm H2O. Conclusions: Low BC and a high △Pdet in the middle and end filling stages are more accurate factors than classic indicators for predicting UUTD. In addition, a DLPP value of >20 cm H2O in the end bladder filling stage shows high sensitivity.

Comparison of the flight ability of diapausing and post-diapause Osmia excavata Alfken (Hymenoptera: Megachilidae) at different temperatures

Lyu Zhaoyun,Liu Haigang,Zhou Ting,Feng Min,Lu Zengbin,Nie Lei,Wang Guiping,Wang Guangzhao,Li Lili,Men Xingyuan,Sun Meng,Yu Yi 한국응용곤충학회 2024 Journal of Asia-Pacific Entomology Vol.27 No.1

The solitary mason bee Osmia excavata Alfken (Hymenoptera: Megachilidae) is an important pollinator of fruit trees in northern China. This stduy compared and studied the flight ability of O. excavata at different temper atures both during and post diapause, with the aim of exploring the feasibility of using O. excavata prematurely released from diapause for pollination. The flight capacity of male and female O. excavata during diapause and post diapause was measured at 3 ◦ C intervals from 10 to 31 ◦ C by using a computer-monitored flight-mill system. The results showed that as the temperature increased, the flight ability also increased until an optimal tem perature was reached, whereupon it gradually decreased regardless of the further increase in temperature. Temperature had a highly significant impact on flight ability (P < 0.01), whereas gender only had a significant effect on average flight distance (P = 0.034). Diapause status had significant effects on average flight distance, average flight speed and maximum flight speed, and the interaction between diapause and temperature had a highly significant impact on average flight distance and average flight speed (P < 0.01). Post diapause, the flying ability of bees was significantly improved; however, diapausing O. excavata demonstrated a sufficient flying ability and so could be used as auxiliary pollinators for fruits in greenhouses during winter and early spring, when there is a shortage of pollinators.

Food search and transport in red imported fire ants (Hymenoptera: Formicidae) under wet conditions

Lin Jintao,Yang Xinya,Lyu Hailong,Chen Xuan,Wang Lei,Wang Cai,Wen Xiujun 한국응용곤충학회 2024 Journal of Asia-Pacific Entomology Vol.27 No.1

The red imported fire ant, Solenopsis invicta Buren, has invaded various wetlands such as beaches, swamps, and mangrove forests. We hypothesize that S. invicta can effectively forage food in these habitats. Here, the food searching and transport by S. invicta on each substrate (sand or soil with freshwater or artificial seawater) at different saturation levels (70%, 100%, 130%, or 160%) were evaluated. Ants walked on unsubmerged substrates (70%- and 100%-saturated) to search for food, and surprisingly, they swam and passed 130%- or 160%-saturated substrates that were submerged with thin layers of water. Saturation level may significantly affect duration of food search and/or transport, depending on substrate types. The number of foraging ants rapidly increased and decreased on the food-releasing platform located on the 70%-saturated substrate and remained stable on the platform located on the 100%-saturated substrate. However, only a few ants were found on the platform located on waterlogged substrates throughout the experiment. In addition, no food was successfully transported passing the waterlogged substrate. We also compared food search and transport among four substrates (sand or soil with freshwater or seawater) at the 70%- or 100%-saturation level. Ants spent similar time searching for food and transporting food on the platform, but minimal food was transported passing the soil with freshwater or seawater. Our results showed that S. invicta can successfully search for food but fail to transport food on waterlogged substrates. In addition, both substrate types and saturation level affected food transport under unsubmerged conditions.

Research on Arch Effect and CFRP Strengthening Effect of RC Beams with Corroded Stirrups

Shuang Chen,Haibo Lyu,Lei Wang,Xin Zhang 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.12

In many cases the corrosion of steel reinforcement is considered to be the main reason that leads to the deterioration of the bond between steel reinforcement and concrete and causes the failure of members. However, stirrups with smaller diameter are more likely to get rusted and it is more difficult to find corrosion expansion cracks on the surface of concrete. Then the function of stirrups to restrict longitudinal bar from slipping will be weakened, which alters the mechanical properties and failure mode of corroded Reinforced Concrete (RC) beams. In this paper, the influence of corrosion of stirrups and the effect of strengthening corroded RC beams with Carbon Fiber Reinforced Polymer (CFRP) sheets were studied. The corrosion rate for each group varied between 0% to 18% which represented mass loss of the longitudinal steel reinforcement on the tension side. The longitudinal reinforcement of beams in Group A was not wrapped by the stirrups in order to simulate the situation that the stirrups were seriously corroded and lost their function. Beams of Group B were corroded control beams. Beams of Group C were corroded and then repaired by applying longitudinal CFRP sheets at the bottom and additional U-shaped CFRP sheets around the cross-section. Test results showed that the corrosion of stirrups had a detrimental effect on strength as well as the bond stress between steel bars and concrete. The mechanical mode of experimental beams tended to act like an arch. The greater the corrosion rate was, the more obvious the arch effect was. In addition, combining longitudinal and U-shaped CFRP sheets enhanced the ultimate load by an average of 56.5% of corroded RC beams. However, because of the longitudinal cracks, the strengthening effect of CFRP was much diminished when the corrosion rate was particularly high.

Analysis of nonlinear vibration response of a functionally graded truncated conical shell with piezoelectric layers

Yuhang Zhang,Wenguang Liu,Zhipeng Lyu,Chao Liu,Lei Pang 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.8

The nonlinear vibration response of a functionally graded materials (FGMs) truncated conical shell with piezoelectric layers is analyzed. The vibration amplitude is suppressed by the positive and inverse piezoelectric effects. And the bifurcation phenomenon is described to reveal the motion state of the conical shell. Firstly, a truncated conical shell composed of three layers is described. And the effective material properties of the FG layer are defined by the Voigt model and the power law distribution. Next, the electric potentials of piezoelectric layers are defined as cosine distribution along the thickness direction. Meanwhile, the constant gain negative velocity feedback algorithm is used to suppress the vibration amplitude by the electric potential produced by the sensor layer. Thereafter, considering the first-order shear deformation theory and the von Karman nonlinearity, the relationship between the strain and displacement is defined. And the corresponding energy of the conical shell is calculated. After that, the motion equations of the conical shell are derived based on the Hamilton principle. Again, the nonlinear single degree of freedom equation is derived by the Galerkin method and the static condensation method. In the end, the nonlinear vibration response of FGMs truncated conical shell with piezoelectric layers under the external excitation is analyzed via using the harmonic balance method and the Runge-Kutta method. The effects of various parameters, such as ceramic volume fraction exponent, external excitation’s amplitude, control gain and geometric parameters on the nonlinear vibration response of the system are evaluated by case studies. Results indicate that the control gain plays an important role on the suppression of the vibration amplitude. The ceramic volume fraction exponents are not sensitive to the nonlinear vibration response compared with other parameters. The bifurcation behavior is observed under different parameters. The FGMs truncated conical shell with piezoelectric layers has three types of motion state, such as periodic motion, multi-periodic motion, and chaos motion.