Polymer Stamps for Imprinting Nanopatterns in Polymer Substrate.

Wu, Jiahao,Amirsadeghi, Alborz,Kim, Jinsoo,Park, Sunggook American Scientific Publishers 2015 Journal of Nanoscience and Nanotechnology Vol.15 No.1

<P>Using a silicone or metallic stamp for imprinting multiscale patterns comprising micro down to nanoscale patterns into polymer substrates often results in significant deformation in the molded substrate and loss of pattern transfer fidelity for nanopatterns. In the worst case, the expensive stamp can also be damaged. One method to reduce the problem is to use polymer as the stamp material, which will reduce both adhesion and thermal stress generated at the stamp/substrate interface. In this paper, stamps made of three different polymer materials, i.e., polydimethylsiloxane (PDMS), PPGDA-based UV resin and TPGDA-based UV-resin, were fabricated from the same master containing nanofluidic structures and the replication fidelity from the master, polymer stamps, to thermal-imprinted poly(methyl methacrylate) substrate (PMMA) was compared. The largest loss of pattern fidelity occurs in the thermal imprinting step. Polymer stamps with higher Young's moduli result in a better fidelity in pattern transfer. With TPGDA-based UV resin stamps, multiscale structures with a nanochannel with minimum width and height of -70 nm can be imprinted onto PMMA substrate together with macro-scale patterns by a single nanoimprinting processes.</P>

Individual Channel Design-based Modeling and Analysis of Three Phase Grid-tied Inverter with Unbalanced Grid Impedance

Weimin Wu,Yun Li,Jiahao Liu,Frede Blaabjerg 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

Three-phase grid-tied inverters are usually designed to operate in symmetric grid impedance. In actual operations, due to the imbalanced loads, three-phase systems with significant single-phase loads, imbalanced power line impedance or the imbalanced short-circuit impedance of the three grid power transformer, the equivalent three-phase grid impedance is unbalanced. It is, consequently, important to develop an effective model and stability analysis method to address three-phase grid-tied inverter with unbalanced grid impedance. Traditionally, the stability of unbalanced system can be analyzed by harmonic linearization technique, however, the model derivation is complex and the controller parameters need second designing. This paper develops the system model in a multivariable frequency domain, by using the individual channel analysis and design (ICAD), simplifying the stability analysis of the unbalanced system. The detailed study on the three-phase LCL filter-based grid-tied inverter under the unbalanced grid impedance condition is presented. Simulation and experiment analysis are carried out on a 380 V/50 Hz/6 kW grid-tied inverter prototype.

Genome‑wide identification of GMP genes in Rosaceae and functional characterization of FaGMP4 in strawberry (Fragaria × ananassa)

Yuanxiu Lin,Jiahao Zhang,Lintai Wu,Yunting Zhang,Qing Chen,Mengyao Li,Yong Zhang,Ya Luo,Yan Wang,Xiaorong Wang,Haoru Tang 한국유전학회 2021 Genes & Genomics Vol.43 No.6

Background GDP-D-mannose pyrophosphorylase (GMP) is one of the key enzymes determining ascorbic acid (AsA) biosynthesis. However, little information about GMP genes is currently available for the Rosaceae species, especially in the AsA-riched cultivated octoploid strawberry (Fragaria × ananassa). Objective To identify the all the GMP genes in Rosaceae, as well as the predominant homologues and the role of GMP genes in strawberry AsA accumulation. Methods In the present study, we performed genome-wide identifcation and comprehensive analysis of the duplicated GMP genes in strawberry and other Rosaceae species by bioinformatics methods, the expression of the GMP genes from cultivated strawberry (Fragaria × ananassa, FaGMP) was specifcally analyzed by qPCR. Finally, the FaGMP4 was transiently overexpressed in strawberry to estimate the role of GMP in regulating AsA accumulation in strawberry. Results As results, a total of 28 GMP genes were identifed in the fve Rosaceae species. The origins of duplication events analysis suggested that most GMP duplications in Rosaceae species were generated from whole genome duplication (WGD). The Ka/Ks ratio suggested that FaGMP genes underwent a stabilization selection. qPCR based expression analysis showed diferent patterns of FaGMP paralogs during fruit ripening, while FaGMP4 expressed higher in the variety containing higher AsA. Overexpression of FaGMP4 in strawberry signifcantly enhanced AsA accumulation. Furthermore, the expression of FaGMP4 under the treatment of blue and red light was largely increased in leaves while signifcantly inhibited in fruit. These results revealed the vital role of FaGMP4 in regulating AsA in strawberry.

Growth behavior and corrosion resistance of graphene oxide/MgAl Layered double hydroxide coating grown on micro-arc oxidation film of magnesium alloys

Yanning Chen,Liang Wu,Wenhui Yao,Jiahao Wu,Yuan Yuan,Bin Jiang,FuSheng Pan 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.117 No.-

The MgAl Layered double hydroxides (LDHs)/graphene oxide (GO) composite film was fabricated in situon the micro-arc oxidation (MAO) film (MAO/LG) of AZ31 magnesium alloy in one step by hydrothermalchemical conversion method. The growth behavior and corrosion properties of LG films were investigated. The results show that the chemical structure, composition and morphology of the LG film willgradually change with the extension of the hydrothermal treatment time based on using the selfdissolvedcation (Mg2+ and Al3+) in the MAO film as the source of growing LDHs without introducingany external metal cations. The potentiodynamic polarization showed that the MAO/LG-12 h coating(1.28 109 A/cm2) after in situ growth for 12 h was more corrosion resistant than the MAO coating(8.49 106 A/cm2). The synergistic effect of GO and LDHs can significantly improve the corrosion protectionability of MAO coating. In addition, the transition process of the growth behavior of the LG filmlayer on the MAO coating is explained in detail.

Surface charge, electroosmotic flow and DNA extension in chemically modified thermoplastic nanoslits and nanochannels

Uba, Franklin I.,Pullagurla, Swathi R.,Sirasunthorn, Nichanun,Wu, Jiahao,Park, Sunggook,Chantiwas, Rattikan,Cho, Yoon-Kyoung,Shin, Heungjoo,Soper, Steven A. The Royal Society of Chemistry 2015 The Analyst Vol.140 No.1

<P>Thermoplastics have become attractive alternatives to glass/quartz for microfluidics, but the realization of thermoplastic nanofluidic devices has been slow in spite of the rather simple fabrication techniques that can be used to produce these devices. This slow transition has in part been attributed to insufficient understanding of surface charge effects on the transport properties of single molecules through thermoplastic nanochannels. We report the surface modification of thermoplastic nanochannels and an assessment of the associated surface charge density, zeta potential and electroosmotic flow (EOF). Mixed-scale fluidic networks were fabricated in poly(methylmethacrylate), PMMA. Oxygen plasma was used to generate surface-confined carboxylic acids with devices assembled using low temperature fusion bonding. Amination of the carboxylated surfaces using ethylenediamine (EDA) was accomplished <I>via</I> EDC coupling. XPS and ATR-FTIR revealed the presence of carboxyl and amine groups on the appropriately prepared surfaces. A modified conductance equation for nanochannels was developed to determine their surface conductance and was found to be in good agreement with our experimental results. The measured surface charge density and zeta potential of these devices were lower than glass nanofluidic devices and dependent on the surface modification adopted, as well as the size of the channel. This property, coupled to an apparent increase in fluid viscosity due to nanoconfinement, contributed to the suppression of the EOF in PMMA nanofluidic devices by an order of magnitude compared to the micro-scale devices. Carboxylated PMMA nanochannels were efficient for the transport and elongation of λ-DNA while these same DNA molecules were unable to translocate through aminated nanochannels.</P> <P>Graphic Abstract</P><P>We report the surface modification of thermoplastic nanochannels and the evaluation of the surface charge density, zeta potential and electroosmotic flow (EOF). <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c4an01439a'> </P>

Treatment of bladder cancer by geoinspired synthetic chrysotile nanocarrier-delivered circPRMT5 siRNA

Chunping Yu,Yi Zhang,Ning Wang,Wensu Wei,Ke Cao,Qun Zhang,Peiying Ma,Dan Xie,Pei Wu,Biao Liu,Jiahao Liu,Wei Xiang,Xing Hu,Xuewen Liu,Jianfei Xie,Jin Tang,Zhi Long,Long Wang,Hongliang Zeng,Jianye Liu 한국생체재료학회 2022 생체재료학회지 Vol.26 No.1

Background: Circular RNAs (circRNAs) have important functions in many fields of cancer biology. In particular, we previously reported that the oncogenic circRNA, circPRMT5, has a major role in bladder cancer progression. Therapy based on circRNAs have good prospects as anticancer strategies. While anti-circRNAs are emerging as therapeutics, the specific in vivo delivery of anti-circRNAs into cancer cells has not been reported and remains challenging. Methods: Synthesized chrysotile nanotubes (SCNTs) with a relatively uniform length (~ 200 nm) have been designed to deliver an siRNA against the oncogenic circPRMT5 (si-circPRMT5) inhibit circPRMT5. In addition, the antitumor effects and safety evaluation of SCNTs/si-circPRMT5 was assessed with a series of in vitro and in vivo assays. Results: The results showed that SCNTs/si-circPRMT5 nanomaterials prolong si-circPRMT5’s half-life in circulation, enhance its specific uptake by tumor cells, and maximize the silencing efficiency of circPRMT5. In vitro, SCNTs encapsulating si-circPRMT5 could inhibit bladder cancer cell growth and progression. In vivo, SCNTs/si-circPRMT5 inhibited growth and metastasis in three bladder tumor models (a subcutaneous model, a tail vein injection lung metastatic model, and an in situ model) without obvious toxicities. Mechanistic study showed that SCNTs/sicircPRMT5 regulated the miR-30c/SNAIL1/E-adherin axis, inhibiting bladder cancer growth and progression. Conclusion: The results highlight the potential therapeutic utility of SCNTs/si-circPRMT5 to deliver si-circPRMT5 to treat bladder cancer.