Structure-Mechanical Property Relationships of 3D-Printed Porous Polydimethylsiloxane

Jiayu Zhao,Rebekah Woo,Grace Chen,Jinhye Bae 한국고분자학회 2021 한국고분자학회 학술대회 연구논문 초록집 Vol.46 No.2

We studied the structure-mechanical property relationship to demonstrate the highly tunable mechanical properties of printed porous PDMS via direct ink writing. To enable 3D printing, we develop a porous PDMS ink consisting of a PDMS precursor, silicone oil, dibutyl phthalate (DBP), and fumed silica nanoparticles by tuning the rheological behaviors. The rheological impact of each component was characterized by viscosity, storage modulus and loss modulus measurements. The porous structures in PDMS are subsequently generated by the removal of DBP in the cured PDMS matrix and characterized by scanning electron microscopy. Mechanical characterization exhibits that the printed sample using the porous PDMS precursor has enhanced stiffness, strength, toughness, and ductility compared to the nonporous PDMS sample. Notably, a broad range of mechanical properties is achieved by varying structural parameters (i.e. , infill densities and printing patterns) for 3D printing of a single porous PDMS material system, which provides insight for designing adaptive soft robots and actuators that can integrate different mechanical properties into a single device by simply changing the structural parameters.

Identification of novel alleles induced by EMS-mutagenesis in key genes of kernel hardness and starch biosynthesis in wheat by TILLING

Wenjie Li,Huijun Guo,Yongbin Wang,Yongdun Xie,Linshu Zhao,Jiayu Gu,Shirong Zhao,Baocun Zhao,Guangjin Wang,Luxiang Liu 한국유전학회 2017 Genes & Genomics Vol.39 No.4

To identify novel allelic variations in key genes of wheat quality, the present study used the targeting induced local lesions in genomes platform to detect point mutations in target genes. The wheat variety Longfumai 17 was treated by the mutagen ethyl methanesulfonate to produce a bulk M2 generation, and the population included 1122 plants. A total length of 3906.80 kb nucleotides was analyzed, and the average mutation density was 1/244.17 kb. The identified mutations included G>A substitutions (43.75%), C>T substitutions (31.25%), A insertions (12.50%), T insertions (6.25%), and deletions (6.25%). These point mutations led to changes in amino acids and thus the encoded protein sequences, ultimately producing 18.75% of missense mutations, 12.50% of frame shift mutations, 6.25% of nonsense mutations, 25.00% of silent mutations and 37.50% of non-coding region mutations. In the kernel hardness gene Pinb and 3 starch synthesis genes waxy, Agp2 and SSIIa-A, we detected 16 different point mutations in 25 mutant lines. The Pinb gene harbored two missense mutations and a nonsense mutation; the C>T missense mutation resulted in a novel allele, this novel allele and the nonsense mutation alerted protein 3D structure; the waxy gene presented missense and frame shift mutations; the Agp2 gene carried a missense mutation; the SSIIa-A incurred a missense mutation and a frame shift mutation that resulted in premature protein termination. All the frame shift mutations, nonsense mutations and the Pinb novel allele resulted in allelic variation of their corresponding genes, which in turn affected their gene functions. The identified mutant lines can be used as intermediate materials in wheat quality improvement schemes.

Development of lady beetle attractants from floral volatiles and other semiochemicals for the biological control of aphids

Jinhao Zhao,Zhongyan Wang,Zhongshan Li,Jiayu Shi,Ling Meng,Guorong Wang,Jingli Cheng,Yongjun Du 한국응용곤충학회 2020 Journal of Asia-Pacific Entomology Vol.23 No.4

Aphids are among the most destructive phytophagous pests of host plants, because of their rapid reproduction, parthenogenesis, extensive crop damage, and the transmission of many plant viruses. Since lady beetles are important predatory natural enemies of aphids, developing lady beetle attractants to increase their field abundance is vital for aphid control. Floral volatiles and other semiochemicals are reportedly attractive to lady beetles. In this research, a total of 58 floral volatiles were tested by Y-tube olfactometer assays, among which 29 were highly attractive to both Harmonia axyridis (Coleoptera: Coccinellidae) and Coccinella septempunctata (Coleoptera: Coccinellidae). Meanwhile, the results of wind tunnel trials showed that only isoamyl acetate, α-humulene, trans-3-hexen-1-ol, methyl salicylate, and β-pinene lure these two species. Thereafter, 15 semiochemicals from pests, natural enemies, and pest-infested crops were mixed with the selected floral volatiles, to determine optimum formulations for attracting lady beetles through wind tunnels and further field trials. Eventually, formulas (1) α-humulene: β-pinene: methyl salicylate: trans-3-hexen-1-ol = 1:3:3:10; (5) α-humulene: β-pinene: methyl salicylate:1-nonanal = 1:3:3:10; (8) α-humulene: β-pinene: methyl salicylate: indole = 1:3:3:10 (1, 5, and 8 are labels used for the various formulations in field trials) were successfully verified to be attractive to lady beetles in both pumpkin and wheat fields. These formulations will be of great significance in developing integrated pest management strategies for aphid control.

Facilely tuning the surface wettability of Cu mesh for multi-functional applications

Xingwang Zhao,Fei Mao,Jiayue Wu,Jinglei Lei,Lingjie Li 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.116 No.-

The Cu meshes with reversible super-wettability have multifunctions of self-cleaning, oil–water separation,floating-oil collection and underwater oil lossless-transportation. However, the facile method totune the surface wettability and prepare reversibly super-wetting Cu meshes remains a great challenge. In this work, one-step chemical-etching method was used to construct the hierarchically-structured CuOof nano-sheets and micro-clusters on Cu meshes to provide suitable surface roughness essential forsuper-wettability. The surface wettability of Cu mesh was then facilely tuned by controlling the adsorptionand desorption of C-containing species at the Cu mesh surface through C-rich ambience storage andIR irradiation for short duration. The super-wetting transition of Cu meshes betweensuperhydrophobicity/superoleophilicity and superhydrophilicity/underwater-superoleophobicity couldrepeat for many cycles. Moreover, the super-wetting Cu meshes demonstrated excellent mechanical,physical and chemical stabilities. The switchable super-wettability endowed the Cu meshes with integratedmulti-functions, which demonstrated remarkable performance of self-cleaning, oil–water separation,floating-oil collection and underwater oil lossless-transportation. This study suggests that utilizingC-rich ambience storage and IR irradiation to control the content of C-containing species at the Cu meshsurface is a facile and effective way to tune the surface wettability of Cu meshes, which can be easilyextended to realize super-wettability transition of various materials.

Design Methodology for Optimal Phase-Shift Modulation of Non-Inverting Buck-Boost Converters

Shi, Bingqing,Zhao, Zhengming,Li, Kai,Feng, Gaohui,Ji, Shiqi,Zhou, Jiayue The Korean Institute of Power Electronics 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.5

The non-inverting buck-boost converter (NIBB) is a step-up and step-down DC-DC converter suitable for wide-input-voltage-range applications. However, when the input voltage is close to the output voltage, the NIBB needs to operate in the buck-boost mode, causing a significant efficiency reduction since all four switches operates in the PWM mode. Considering both the current stress limitation and the efficiency optimization, a novel design methodology for the optimal phase-shift modulation of a NIBB in the buck-boost mode is proposed in this paper. Since the four switches in the NIBB form two bridges, the shifted phase between the two bridges can serve as an extra degree of freedom for performance optimization. With general phase-shift modulation, the analytic current expressions for every duty ratio, shifted phase and input voltage are derived. Then with the two key factors in the NIBB, the converter efficiency and the switch current stress, taken into account, an objective function with constraints is derived. By optimizing the derived objective function over the full input voltage range, an offline design methodology for the optimal modulation scheme is proposed for efficiency optimization on the premise of current stress limitation. Finally, the designed optimal modulation scheme is implemented on a DSPs and the design methodology is verified with experimental results on a 300V-1.5kW NIBB prototype.

Sequential Self-folding of Nanocomposite Hydrogel/Elastomer Layers

Jinhye Bae,Jiayu Zhao 한국고분자학회 2022 한국고분자학회 학술대회 연구논문 초록집 Vol.47 No.1

Sensorless Control of the Switched Reluctance Motor Based on the Sliding-Mode Observer

Li Xinyu,Liu Jiayu,Ge Lefei,Zhong Jixi,Huang Jiale,Zhao Yuchen,Song Shoujun 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.2

To upgrade the application of switched reluctance motors (SRMs) for more electric aircraft, this paper presents a method with sensorless control based on the flux-linkage data from the finite element method. First, a calibration strategy is employed to obtain the flux-linkage characteristics. Then, a sliding-mode observer is used to realize the sensorless control of the SRM. The proposed method only requires the flux-linkage of the SRM at aligned and unaligned rotor positions from the experiment which takes a low-measurement effort to get the rotor position and has better accuracy in position and speed estimation than the FEM. Experimental results verify the accuracy and effectiveness of the proposed method.

Design Methodology for Optimal Phase-Shift Modulation of Non-Inverting Buck-Boost Converters

Bingqing Shi,Zhengming Zhao,Kai Li,Gaohui Feng,Shiqi Ji,Jiayue Zhou 전력전자학회 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.5

The non-inverting buck-boost converter (NIBB) is a step-up and step-down DC-DC converter suitable for wide-input-voltagerange applications. However, when the input voltage is close to the output voltage, the NIBB needs to operate in the buck-boost mode, causing a significant efficiency reduction since all four switches operates in the PWM mode. Considering both the current stress limitation and the efficiency optimization, a novel design methodology for the optimal phase-shift modulation of a NIBB in the buck-boost mode is proposed in this paper. Since the four switches in the NIBB form two bridges, the shifted phase between the two bridges can serve as an extra degree of freedom for performance optimization. With general phase-shift modulation, the analytic current expressions for every duty ratio, shifted phase and input voltage are derived. Then with the two key factors in the NIBB, the converter efficiency and the switch current stress, taken into account, an objective function with constraints is derived. By optimizing the derived objective function over the full input voltage range, an offline design methodology for the optimal modulation scheme is proposed for efficiency optimization on the premise of current stress limitation. Finally, the designed optimal modulation scheme is implemented on a DSPs and the design methodology is verified with experimental results on a 300V-1.5kW NIBB prototype.

Surgically Inspired Technique of ITZ Integration in Lattice Model for Numerical Simulation of Cement Composites

Xinchun Guan,Shengying Zhao,Jiayu Liu 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.11

The extent to which an Interfacial Transition Zone (ITZ) contributes to mechanical behavior of cement pastes and mortars is under debate. To investigate this debatable issue, a new organ-transplantation-mimetic technique for building up a 3-D ITZ, which can be embedded into mortar and concrete to numerically simulate their mechanical behaviors, is developed. Inspired by serotyping through which transplant rejection can be reduced, we define a Compatibility Factor (CF), an index for evaluating to which degree two moieties are likely to reject. Thus the moieties of the integrated ITZ exhibit good compatibility with each other and so does the ITZ with bulk paste. For the first time, the established model enables one to endow ITZ elements at different loci with varying properties according to ITZ-load orientation and of ITZ thickness, both of which are demonstrated to have notable impacts on ITZ’s mechanical properties by numerically simulated tensile load tests in micro- and meso-scale levels. Besides mechanical performances, this novel approach is potentially capable of predicting transport properties such as ion diffusivity.

Single-cell transcriptomic analysis reveals transcriptional and cell subpopulation differences between human and pig immune cells

Li Jie,Xu Yanan,Zhang Jiayu,Zhang Zhaoqi,Guo Han,Wei Dong,Wu Changhong,Hai Tang,Sun Hai-Xi,Zhao Yong 한국유전학회 2024 Genes & Genomics Vol.46 No.3

Background The pig is a promising donor candidate for xenotransplantation. Understanding the differences between human and swine immune systems is critical for addressing xenotransplant rejection and hematopoietic reconstitution. The gene transcriptional profile differences between human and pig immune cell subpopulations have not been studied. To assess the similarities and differences between pigs and humans at the levels of gene transcriptional profiles or cell subpopulations are important for better understanding the cross-species similarity of humans and pigs, and it would help establish the fundamental principles necessary to genetically engineer donor pigs and improve xenotransplantation. Objective To assess the gene transcriptional similarities and differences between pigs and humans. Methods Two pigs and two healthy humans’ PBMCs were sorted for 10 × genomics single-cell sequence. We generated integrated human-pig scRNA-seq data from human and pig PBMCs and defined the overall gene expression landscape of pig peripheral blood immune cell subpopulations by updating the set of human-porcine homologous genes. The subsets of immune cells were detected by flow cytometry. Results There were significantly less T cells, NK cells and monocytes but more B cells in pig peripheral blood than those in human peripheral blood. High oxidative phosphorylation, HIF-1, glycolysis, and lysosome-related gene expressions in pig CD14+ monocytes were observed, whereas pig CD14+ monocytes exhibited lower levels of cytokine receptors and JAK-STAT-related genes. Pig activated CD4+T cells decreased cell adhesion and inflammation, while enriched for migration and activation processes. Porcine GNLY+CD8+T cells reduced cytotoxicity and increased proliferation compared with human GNLY+CD8+T cells. Pig CD2+CD8+γδT cells were functionally homologous to human CD2+CD4+ γδT cells. Pig CD2−CD8−γδT cells expressed genes with quiescent and precursor characteristics, while CD2−CD8+γδT cells expressed migration and memory-related molecules. Pig CD24+ and CD5+B cells are associated with inflammatory responses. Conclusion Our research with integrated scRNA-seq assays identified the different distribution of pig immune cell subpopulations and the different transcriptional profiles of human and pig immune cells. This study enables a deeper understanding of the development and function of porcine immune cells. Background The pig is a promising donor candidate for xenotransplantation. Understanding the differences between human and swine immune systems is critical for addressing xenotransplant rejection and hematopoietic reconstitution. The gene transcriptional profile differences between human and pig immune cell subpopulations have not been studied. To assess the similarities and differences between pigs and humans at the levels of gene transcriptional profiles or cell subpopulations are important for better understanding the cross-species similarity of humans and pigs, and it would help establish the fundamental principles necessary to genetically engineer donor pigs and improve xenotransplantation. Objective To assess the gene transcriptional similarities and differences between pigs and humans. Methods Two pigs and two healthy humans’ PBMCs were sorted for 10 × genomics single-cell sequence. We generated integrated human-pig scRNA-seq data from human and pig PBMCs and defined the overall gene expression landscape of pig peripheral blood immune cell subpopulations by updating the set of human-porcine homologous genes. The subsets of immune cells were detected by flow cytometry. Results There were significantly less T cells, NK cells and monocytes but more B cells in pig peripheral blood than those in human peripheral blood. High oxidative phosphorylation, HIF-1, glycolysis, and lysosome-related gene expressions in pig CD14+ monocytes were observed, whereas pig CD14+ monocytes exhibited lower levels of cytokine receptors and JAK-STAT-related genes. Pig activated CD4+T cells decreased cell adhesion and inflammation, while enriched for migration and activation processes. Porcine GNLY+CD8+T cells reduced cytotoxicity and increased proliferation compared with human GNLY+CD8+T cells. Pig CD2+CD8+γδT cells were functionally homologous to human CD2+CD4+ γδT cells. Pig CD2−CD8−γδT cells expressed genes with quiescent and precursor characteristics, while CD2−CD8+γδT cells expressed migration and memory-related molecules. Pig CD24+ and CD5+B cells are associated with inflammatory responses. Conclusion Our research with integrated scRNA-seq assays identified the different distribution of pig immune cell subpopulations and the different transcriptional profiles of human and pig immune cells. This study enables a deeper understanding of the development and function of porcine immune cells.