Evaluation of Different Yeast Species for Improving In vitro Fermentation of Cereal Straws

Wang, Zuo,He, Zhixiong,Beauchemin, Karen A.,Tang, Shaoxun,Zhou, Chuanshe,Han, Xuefeng,Wang, Min,Kang, Jinhe,Odongo, Nicholas E.,Tan, Zhiliang Asian Australasian Association of Animal Productio 2016 Animal Bioscience Vol.29 No.2

Information on the effects of different yeast species on ruminal fermentation is limited. This experiment was conducted in a $3{\times}4$ factorial arrangement to explore and compare the effects of addition of three different live yeast species (Candida utilis 1314, Saccharomyces cerevisiae 1355, and Candida tropicalis 1254) at four doses (0, $0.25{\times}10^7$, $0.50{\times}10^7$, and $0.75{\times}10^7$ colony-forming unit [cfu]) on in vitro gas production kinetics, fiber degradation, methane production and ruminal fermentation characteristics of maize stover, and rice straw by mixed rumen microorganisms in dairy cows. The maximum gas production (Vf), dry matter disappearance (IVDMD), neutral detergent fiber disappearance (IVNDFD), and methane production in C. utilis group were less (p<0.01) than other two live yeast supplemented groups. The inclusion of S. cerevisiae reduced (p<0.01) the concentrations of ammonia nitrogen ($NH_3$-N), isobutyrate, and isovalerate compared to the other two yeast groups. C. tropicalis addition generally enhanced (p<0.05) IVDMD and IVNDFD. The $NH_3$-N concentration and $CH_4$ production were increased (p<0.05) by the addition of S. cerevisiae and C. tropicalis compared with the control. Supplementation of three yeast species decreased (p<0.05) or numerically decreased the ratio of acetate to propionate. The current results indicate that C. tropicalis is more preferred as yeast culture supplements, and its optimal dose should be $0.25{\times}10^7$ cfu/500 mg substrates in vitro.

Expeditus: Congestion-Aware Load Balancing in Clos Data Center Networks

Wang, Peng,Xu, Hong,Niu, Zhixiong,Han, Dongsu,Xiong, Yongqiang IEEE 2017 IEEE/ACM transactions on networking Vol.25 No.5

<P>Data center networks often use multi-rooted Clos topologies to provide a large number of equal cost paths between two hosts. Thus, load balancing traffic among the paths is important for high performance and low latency. However, it is well known that ECMP-the de facto load balancing scheme-performs poorly in data center networks. The main culprit of ECMP's problems is its congestion agnostic nature, which fundamentally limits its ability to deal with network dynamics. We propose Expeditus, a novel distributed congestion-aware load balancing protocol for general 3-tier Clos networks. The complex 3-tier Clos topologies present significant scalability challenges that make a simple per-path feedback approach infeasible. Expeditus addresses the challenges by using simple local information collection, where a switch only monitors its egress and ingress link loads. It further employs a novel two-stage path selection mechanism to aggregate relevant information across switches and make path selection decisions. Testbed evaluation on Emulab and large-scale ns-3 simulations demonstrate that, Expeditus outperforms ECMP by up to 45% in tail flow completion times (FCT) for mice flows, and by up to 38% in mean FCT for elephant flows in 3-tier Clos networks.</P>

Large-scale Field Tests of the Performance of Geogrid-reinforced Piled Embankment over Soft Soil

Gang Wang,Xianwei Zhang,Xinyu Liu,Zhixiong Chang,Zhihai Liu 대한토목학회 2024 KSCE Journal of Civil Engineering Vol.28 No.2

When constructing superstructures on soft soils, geogrid-reinforced embankments and pile-supported embankments are used widely to improve the soft foundation and prevent issues including excessive settlements and large lateral displacements, so it is crucial to understand and evaluate their performance systematically. This study focuses on a case of piled embankments for a motor-racing circuit under construction in China. Two large-scale field tests of pile-supported embankments with and without reinforcement were carried out to investigate the effect of geosynthetic reinforcement on the improvement of embankments. During long-term monitoring, instruments in the test sites measured earth pressures, settlements, lateral displacements, and pore water pressures, and the performances of the reinforced or unreinforced embankments were examined. Test results from the two test sites under similar loading are compared, and it is concluded that the geosynthetic-reinforcement considerably influences the improvement of load transfer and diminishment of total and differential settlements. The lateral restraint provided by the geogrids also reduced the lateral soil displacement and the influence of subsoil depth. The smaller excessive pore water pressures in the site with reinforcement were associated with the enhanced load transfer due to the geogrids. This study provides an important reference for the design and construction of this circuit and other related projects.

Structural damage identification using an iterative two-stage method combining a modal energy based index with the BAS algorithm

Shuqing Wang,Yufeng Jiang,Mingqiang Xu,Yingchao Li,Zhixiong Li 국제구조공학회 2020 Steel and Composite Structures, An International J Vol.36 No.1

The purpose of this study is to develop an effective iterative two-stage method (ITSM) for structural damage identification of offshore platform structures. In each iteration, a new damage index, Modal Energy-Based Damage Index (MEBI), is proposed to help effectively locate the potential damage elements in the first stage. Then, in the second stage, the beetle antenna search (BAS) algorithm is used to estimate the damage severity of these elements. Compared with the well-known particle swarm optimization (PSO) algorithm and genetic algorithm (GA), this algorithm has lower computational cost. A modal energy based objective function for the optimization process is proposed. Using numerical and experimental data, the efficiency and accuracy of the ITSM are studied. The effects of measurement noise and spatial incompleteness of mode shape are both considered. All the obtained results show that under these influences, the ITSM can accurately identify the true location and severity of damage. The results also show that the objective function based on modal energy is most suitable for the ITSM compared with that based on flexibility and weighted natural frequency-mode shape.

Effect of plant secondary metabolites on common cutworm, Spodoptera litura (Lepidoptera: Noctuidae)

Qi Su,Zhixiong ZHOU,Jianmin ZHANG,Caihua SHI,Guohui ZHANG,Zhenyu JIN,Wenkai WANG,Chuanren LI 한국곤충학회 2018 Entomological Research Vol.48 No.1

The effect of various flavonoids, lectins and phenyl β‐D‐glucoside on larval survival, weights and the activities of digestive (total serine protease and trypsin) and detoxifying (esterase and glutathione‐S‐transferase) enzymes of Spodoptera litura larvae at 7 days after treatment was studied through diet incorporation assay. Flavonoids (rutin, chlorogenic acid, quinic acid, caffeic acid, naringenin, quercitin, kaempferol, myricetin, catechin, and ferulic acid) were incorporated in artificial diet at 100, 500 and 1000 ppm, lectins: groundnut leaf lectin (GLL), concavalin A (ConA) and phenyl β‐D‐glucoside at 1, 2 and 5 μg/mL. Flavonoids such as rutin, quercitin and kaempferol at 1000 ppm were more toxic to S. litura larvae than quinic acid, caffeic acid, naringenin, myricetin, catechin, and ferulic acid. Larval growth and development were significantly reduced in S. litura larvae fed on a diet with GLL and ConA at 5 μg/mL compared to the larvae fed at 2 and 1 μg/mL concentrations. The larvae fed on flavonoid‐treated diets showed significant reduction in serine protease, trypsin and esterase activities. The flavonoids such as rutin, chlorogenic acid, quinic acid, naringenin, quercitin, kaempferol and myricetin, and lectins, GLL and ConA can be utilized in insect control programs.

Effects of dietary leucine supplementation on the hepatic mitochondrial biogenesis and energy metabolism in normal birth weight and intrauterine growth-retarded weanling piglets

Weipeng Su,Wen Xu,Hao Zhang,Zhixiong Ying,Le Zhou,Lili Zhang,Tian Wang 한국영양학회 2017 Nutrition Research and Practice Vol.11 No.2

BACKGROUND/OBJECTIVES: The study was conducted to evaluate the effects of dietary leucine supplementation on mitochondrial biogenesis and energy metabolism in the liver of normal birth weight (NBW) and intrauterine growth-retarded (IUGR) weanling piglets. MATERIALS/METHODS: A total of sixteen pairs of NBW and IUGR piglets from sixteen sows were selected according to their birth weight. At postnatal day 14, all piglets were weaned and fed either a control diet or a leucine-supplemented diet for 21 d. Thereafter, a 2 × 2 factorial experimental design was used. Each treatment consisted of eight replications with one piglet per replication. RESULTS: Compared with NBW piglets, IUGR piglets had a decreased (P < 0.05) hepatic adenosine triphosphate (ATP) content. Also, IUGR piglets exhibited reductions (P < 0.05) in the activities of hepatic mitochondrial pyruvate dehydrogenase (PDH), citrate synthase (CS), α-ketoglutarate dehydrogenase (α-KGDH), malate dehydrogenase (MDH), and complexes I and V, along with decreases (P < 0.05) in the concentration of mitochondrial DNA (mtDNA) and the protein expression of hepatic peroxisome proliferator-activated receptor-γ coactivator 1α (PGC-1α). Dietary leucine supplementation increased (P < 0.05) the content of ATP, and the activities of CS, α-KGDH, MDH, and complex V in the liver of piglets. Furthermore, compared to those fed a control diet, piglets given a leucine-supplemented diet exhibited increases (P < 0.05) in the mtDNA content and in the mRNA expressions of sirtuin 1, PGC-1α, nuclear respiratory factor 1, mitochondrial transcription factor A, and ATP synthase, H+ transporting, mitochondrial F1 complex, β polypeptide in liver. CONCLUSIONS: Dietary leucine supplementation may exert beneficial effects on mitochondrial biogenesis and energy metabolism in NBW and IUGR weanling piglets.

Effects of Momordica charantia Saponins on In vitro Ruminal Fermentation and Microbial Population

Kang, Jinhe,Zeng, Bo,Tang, Shaoxun,Wang, Min,Han, Xuefeng,Zhou, Chuanshe,Yan, Qiongxian,He, Zhixiong,Liu, Jinfu,Tan, Zhiliang Asian Australasian Association of Animal Productio 2016 Animal Bioscience Vol.29 No.4

This study was conducted to investigate the effects of Momordica charantia saponin (MCS) on ruminal fermentation of maize stover and abundance of selected microbial populations in vitro. Five levels of MCS supplements (0, 0.01, 0.06, 0.30, 0.60 mg/mL) were tested. The pH, $NH_3-N$, and volatile fatty acid were measured at 6, 24, 48 h of in vitro mixed incubation fluids, whilst the selected microbial populations were determined at 6 and 24 h. The high dose of MCS increased the initial fractional rate of degradation at t-value = 0 ($FRD_0$) and the fractional rate of gas production (k), but decreased the theoretical maximum of gas production ($V_F$) and the half-life ($t_{0.5}$) compared with the control. The $NH_3-N$ concentration reached the lowest concentration with 0.01 mg MCS/mL at 6 h. The MSC inclusion increased (p<0.001) the molar proportion of butyrate, isovalerate at 24 h and 48 h, and the molar proportion of acetate at 24 h, but then decreased (p<0.05) them at 48 h. The molar proportion of valerate was increased (p<0.05) at 24 h. The acetate to propionate ratio (A/P; linear, p<0.01) was increased at 24 h, but reached the least value at the level of 0.30 mg/mL MCS. The MCS inclusion decreased (p<0.05) the molar proportion of propionate at 24 h and then increased it at 48 h. The concentration of total volatile fatty acid was decreased (p<0.001) at 24 h, but reached the greatest concentration at the level of 0.01 mg/mL and the least concentration at the level of 0.60 mg/mL. The relative abundance of Ruminococcus albus was increased at 6 h and 24 h, and the relative abundance of Fibrobacter succinogenes was the lowest (p<0.05) at 0.60 mg/mL at 6 h and 24 h. The relative abundance of Butyrivibrio fibrisolvens and fungus reached the greatest value (p<0.05) at low doses of MCS inclusion and the least value (p<0.05) at 0.60 mg/mL at 24 h. The present results demonstrates that a high level of MCS quickly inhibits in vitro fermentation of maize stover, while MCS at low doses has the ability to modulate the ruminal fermentation pattern by regulating the number of functional rumen microbes including cellulolytic bacteria and fungi populations, and may have potential as a feed additive applied in the diets of ruminants.

Numerical simulation of flow and heat transfer characteristic in straight-through labyrinth seals of aeroengines under eccentric and rotating conditions

Xin Wei,Zhaohui Yao,Feng Jin,Zhixiong Wang,Honghu Ji 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.6

In order to investigate the leakage and heat transfer of eccentric labyrinth seals, the flow and heat transfer process of eccentric and rotating straight-through labyrinth seals were numerically simulated. The research results show that the influence of eccentricity and rotation on the leakage coefficient is very small, and the change range is less than 2 %. Under the condition of non-eccentricity, the influence of rotating speed on the leakage coefficient depends on the rotating Taylor number. When the Taylor number is greater than 34.2, the leakage coefficient decreases slightly with the increase of rotating speed. At the same pressure ratio and rotating speed, the average Nusselt number of stator is greater than that of rotor. With the increase of eccentricty, the average Nusselt number of the section with larger clearance increases gradually, while the average Nusselt number of the section with smaller clearance decreases gradually.