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https://www.readbyqxmd.com/read/28213257/a-zeolitic-imidazolate-framework-based-nanoporous-carbon-as-a-novel-fiber-coating-for-solid-phase-microextraction-of-pyrethroid-pesticides
#1
Shuaihua Zhang, Qian Yang, Xiumin Yang, Wenchang Wang, Zhi Li, Lihong Zhang, Chun Wang, Zhi Wang
A high-surface-area nanoporous carbon (NPC) has been successfully synthesized by using the metal-organic framework ZIF-90 as both the template and precursor together with furfuryl alcohol as a secondary carbon source. The prepared ZIF-90 templated NPC (ZIF-90-NPC) was then coated onto a stainless steel wire by a simple physical adhesion approach to prepare solid-phase microextraction (SPME) fiber. By coupling the ZIF-90-NPC coated fiber-based SPME with gas chromatography-microelectron capture detection (GC-μECD), the developed method gave a large enhancement factor (984-2869), low limit of detection (0...
May 1, 2017: Talanta
https://www.readbyqxmd.com/read/28211275/suppression-of-hydrogen-evolution-by-oxygen-reduction-in-nanoporous-electrocatalysts
#2
Ellen Benn, Bernard Gaskey, Jonah D Erlebacher
Electroreduction of small molecules in aqueous solution often competes with the hydrogen evolution reaction (HER), especially if the reaction is driven even moderately hard using a large overpotential. Here, the oxygen reduction reaction (ORR) was studied under proton diffusion-limited conditions in slightly acidic electrolytes - a model system to study the relative transport kinetics of protons and reactants to an electrocatalyst and the relationship between transport and catalytic performance. Using dealloyed nanoporous nickel-platinum (np-NiPt) electrodes, we find the hydrogen evolution reaction can be completely suppressed even at high overpotentials (-400 mV vs...
February 17, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28209027/silicon-nanostructures-produced-by-modified-macetch-method-for-antireflective-si-surface
#3
Stepan Nichkalo, Anatoly Druzhinin, Anatoliy Evtukh, Oleg Bratus', Olga Steblova
This work pertains to the method for modification of silicon (Si) wafer morphology by metal-assisted chemical etching (MacEtch) technique suitable for fabrication of antireflective Si surfaces. For this purpose, we made different Au catalyst patterns on the surface of Si substrate. This modification allowed to obtain the close-packed Au nanodrop (ND) pattern that generates the nanowires (NWs) and the well-separated Au NDs, which induce the nanopore (NP) formation. The antireflective properties of these structures in comparison with NWs produced by the conventional Ag-MacEtch method were analysed...
December 2017: Nanoscale Research Letters
https://www.readbyqxmd.com/read/28208324/adsorption-induced-shape-transitions-in-bistable-nanopores-with-atomically-thin-walls
#4
Oleg E Shklyaev, Milton W Cole, Vincent H Crespi
Atomically thin cylindrical nanopores can change shape in response to physically adsorbed gas inside. Coupled to a gas reservoir, an initially collapsed pore can expand to allow the adsorbed gas to form concentric shells on the inner part of the pore, driven by adsorption energetics, not gas pressure. A lattice gas model describes the evolution of the nanotube pore shape and absorbed gas as a function of gas chemical potential at zero temperature. We found that narrow-enough tubes are always expanded and gas inside adsorbs in sequences of concentric shells as the gas chemical potential increases...
January 2017: Physical Review. E
https://www.readbyqxmd.com/read/28208315/tracer-counterpermeation-analysis-of-diffusivity-in-finite-length-nanopores-with-and-without-single-file-dynamics
#5
David M Ackerman, James W Evans
We perform a tracer counterpermeation (TCP) analysis for a stochastic model of diffusive transport through a narrow linear pore where passing of species within the pore is inhibited or even excluded (single-file diffusion). TCP involves differently labeled but otherwise identical particles from two decoupled infinite reservoirs adsorbing into opposite ends of the pore, and desorbing from either end. In addition to transient behavior, we assess steady-state concentration profiles, spatial correlations, particle number fluctuations, and diffusion fluxes through the pore...
January 2017: Physical Review. E
https://www.readbyqxmd.com/read/28208062/nano-suspension-coating-as-a-technique-to-modulate-the-drug-release-from-controlled-porosity-osmotic-pumps-for-a-soluble-agent
#6
Leila Azharshekoufeh Bahari, Yousef Javadzadeh, Mohammad Barzegar Jalali, Peyvand Johari, Ali Nokhodchi, Javad Shokri
In controlled porosity osmotic pumps (CPOP), usually finding a single solvent with a capability to dissolve both film former (hydrophobic) and pore former (hydrophilic) is extremely challenging. Therefore, the aim of the present investigation was to tackle the issue associated with controlled porosity osmotic pump (CPOP) system using nano-suspension coating method. In the present study 4-Amino pyridine was used as a highly water soluble drug. In this method, a hydrophilic pore former (sucrose or mannitol) in nano range was suspended in polymeric coating solution using ball-mill...
February 8, 2017: Colloids and Surfaces. B, Biointerfaces
https://www.readbyqxmd.com/read/28206764/host-guest-chemistry-at-integrated-porous-space-formed-by-molecular-self-assembly-at-liquid-solid-interfaces
#7
Kohei Iritani, Kazukuni Tahara, Steven De Feyter, Yoshito Tobe
Host-guest chemistry in two-dimensional space, that is physisorbed monolayers of a single atom or a single molecular thickness on surfaces, has become a subject of intense current interest because of perspectives for various applications in molecular-scale electronics, selective sensors, and tailored catalysis. Scanning tunneling microscopy, with which we can visualize molecules in actual space, has been used as a powerful tool. For more than a decade, we have been investigating the self-assembly of a series of triangle-shaped molecules with a phenylene-ethynylene macrocycle, called dehydrobenzo[12]annulenes (DBAs), substituted by six flexible alkyl chains, forming hexagonal porous 2D molecular networks via van der Waals interactions between interdigitated alkyl chains at the interface of organic solvent and graphite...
February 16, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28199082/influence-of-solvent-on-the-structure-of-an-amphiphilic-block-copolymer-in-solution-and-in-formation-of-an-integral-asymmetric-membrane
#8
Maryam Radjabian, Clarissa Abetz, Birgit Fischer, Andreas Meyer, Volker Abetz
Nanoporous membranes with tailored size pores and multifunctionality derived from self-assembled block copolymers attract growing interest in ultrafiltration. The influence of the structure of block copolymer in the membrane casting solution on the formation of integral asymmetric isoporous block copolymer membranes using the nonsolvent induced phase separation process (NIPS) has been one of the long-standing questions in this research area. In this work we studied the principal role of the solvent on the micellization and self-assembly of asymmetric polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP) diblock copolymers by using a combination of dynamic light scattering (DLS) and small-angle X-ray scattering (SAXS)...
February 15, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28197584/nanoscale-tailor-made-membranes-for-precise-and-rapid-molecular-sieve-separation
#9
Jing Wang, Junyong Zhu, Yatao Zhang, Jindun Liu, Bart Van der Bruggen
The precise and rapid separation of different molecules from aqueous, organic solutions and gas mixtures is critical to many technologies in the context of resource-saving and sustainable development. The strength of membrane-based technologies is well recognized and they are extensively applied as cost-effective, highly efficient separation techniques. Currently, empirical-based approaches, lacking an accurate nanoscale control, are used to prepare the most advanced membranes. In contrast, nanoscale control renders the membrane molecular specificity (sub-2 nm) necessary for efficient and rapid molecular separation...
February 15, 2017: Nanoscale
https://www.readbyqxmd.com/read/28195458/tuning-the-interfacial-activity-of-mesoporous-silicas-for-biphasic-interface-catalysis-reactions
#10
Fen Xue, Yabin Zhang, Fengwei Zhang, Xiaomin Ren, Hengquan Yang
Interface-active particle materials that are able to assemble at the oil/water interface so as to stabilize droplets, are gaining unprecedented interest due to the intriguing applications in catalysis and materials synthesis, etc. In contrast to these potential applications, this kind of materials are still limited and cannot meet some particular demands of practical utilizations such as rationally designed interfacial activity and high stability against concentrated salts. In this contribution, interface-active mesoporous silica nanospheres (MSS@CxZy) are synthesized through simultaneous incorporation of extremely hydrophilic zwitterionic moiety and hydrophobic octyl moiety in the shell...
February 14, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28195433/enzyme-immobilized-nanoporous-carbons-derived-from-metal-organic-framework-a-new-support-for-biodiesel-synthesis
#11
Li-Hao Liu, Yung-Han Shih, Wan-Ling Liu, Chia-Her Lin, Hsi-Ya Huang
In this study, nanoporous carbon (NPC) derived from metal-organic framework (MOF) was used as support for the immobilization of Burkholderia cepacia lipase. The decorated aluminum oxide within the mesoporous NPC facilitated the enzyme loading efficiency as well as catalytic ability for transesterification of soybean oil thus making it green and sustainable technique for industrial application.
February 13, 2017: ChemSusChem
https://www.readbyqxmd.com/read/28195400/hypersonic-poration-a-new-versatile-cell-poration-method-to-enhance-cellular-uptake-using-a-piezoelectric-nano-electromechanical-device
#12
Zhixin Zhang, Yanyan Wang, Hongxiang Zhang, Zifan Tang, Wenpeng Liu, Yao Lu, Zefang Wang, Haitao Yang, Wei Pang, Hao Zhang, Daihua Zhang, Xuexin Duan
Efficient delivery of genes and therapeutic agents to the interior of the cell is critical for modern biotechnology. Herein, a new type of chemical-free cell poration method-hypersonic poration-is developed to improve the cellular uptake, especially the nucleus uptake. The hypersound (≈GHz) is generated by a designed piezoelectric nano-electromechanical resonator, which directly induces normal/shear stress and "molecular bombardment" effects on the bilayer membranes, and creates reversible temporal nanopores improving the membrane permeability...
February 13, 2017: Small
https://www.readbyqxmd.com/read/28195224/crystal-shape-controlled-h2-storage-rate-in-nanoporous-carbon-composite-with-ultra-fine-pt-nanoparticle
#13
Tsan-Yao Chen, Yanhui Zhang, Liang-Ching Hsu, Alice Hu, Yu Zhuang, Chia-Ming Fan, Cheng-Yu Wang, Tsui-Yun Chung, Cheng-Si Tsao, Haw-Yeu Chuang
This study demonstrates that the hydrogen storage rate (HSR) of nanoporous carbon supported platinum nanocatalysts (NC) is determined by their heterojunction and geometric configurations. The present NC is synthesized in an average particle size of ~1.5 nm by incipient wetness impregnation of Pt(4+) at carbon support followed by annealing in H(2) ambient at 102-105 °C. Among the steps in hydrogen storage, decomposition of H2 molecule into 2 H atoms on Pt NC surface is the deciding factor in HSR that is controlled by the thickness of Pt NC...
February 14, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28194985/nano-endoscopy-with-plasmon-enhanced-fluorescence-for-sensitive-sensing-inside-ultrasmall-volume-samples
#14
Hang Yuan, Jie Liu, Yuexiang Lu, Zhe Wang, Guoyu Wei, Tianhao Wu, Gang Ye, Jing Chen, Sichun Zhang, Xinrong Zhang
Plasmon-enhanced fluorescence (PEF) generally requires the samples settled on a metal substrate and the effective enhancement distance is less than 100 nm, which limit its application in intracellular sensing. Herein, we report a nano endoscopy with PEF effect for sensing analytes inside the extremely small volume samples. The nano endoscopy was fabricated by assembling single nanoporous gold nanowire (PGNW) on the tip of a tungsten needle. It was accurately manipulated to insert into a micro droplet, and an effective sensing was realized at micrometre scale with submicrometer resolution...
January 17, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28194951/electrostatic-ion-enrichment-in-an-ultrathin-layer-cell-with-a-critical-dimension-between-5-and-20-nm
#15
Jin Lu, Bo Zhang
Electrostatic interactions play an essential role in many analytical applications including molecular sensing and transport studies using nanopores and separation of charged species. Here, we report the voltammetric quantification of electrostatic ion enrichment in a 5-20 nm thin electrochemical cell. A simple lithographic micro/nanofabrication process was used to create ultrathin-layer cells (UTLCs) with a critical dimension (i.e., cell thickness) as small as 5 nm. The voltammetric response of a UTLC was found to be largely dominated by the electrostatic interaction between charges on the cell walls and the redox species...
February 10, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28192937/amplification-and-quantification-of-an-antisense-oligonucleotide-from-target-microrna-using-programmable-dna-and-a-biological-nanopore
#16
Moe Hiratani, Masayuki Ohara, Ryuji Kawano
This paper describes a strategy for autonomous diagnoses of cancers using microRNA (miRNA) and therapy for tumor cells by DNA computing techniques and nanopore measurement. Theranostics, which involves the combination of diagnosis and therapy, has emerged as an approach for personalized medicine or point-of-care cancer diagnostics. DNA computing will become a potent tool for theranostics because it functions completely autonomously without the need for external regulations. However, conventional theranostics using DNA computing involves a one-to-one reaction in which a single input molecule generates a single output molecule; the concentration of the antisense drug is insufficient for the therapy in this type of reaction...
February 9, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28186777/highly-controlled-nanoporous-ag-electrode-by-vaporization-control-of-2-ethoxyethanol-for-a-flexible-supercapacitor-application
#17
Jinwoo Lee, Jaehak Lee, Jinhyeong Kwon, Habeom Lee, Hyeonjin Eom, Yeosang Yoon, Inho Ha, Minyang Yang, Seung Hwan Ko
Controlling the surface morphology of the electrode on the nanoscale has been studied extensively because the surface morphology of a material directly leads to the functionalization in various fields of studies. In this study, we designed a simple and cost-effective method to fine-tune the surface morphology and create controlled nanopores on the silver electrode by utilizing 2-ethoxyethanol and two successive heat treatments. High electrical conductivity and mechanical robustness of nanoporous silver corroborate its prospect to be employed in various applications requiring a certain degree of flexibility...
February 10, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28184162/synergistic-effect-of-nanotopography-and-bioactive-ions-on-peri-implant-bone-response
#18
Yingmin Su, Satoshi Komasa, Peiqi Li, Mariko Nishizaki, Luyuan Chen, Chisato Terada, Shigeki Yoshimine, Hiroshi Nishizaki, Joji Okazaki
Both bioactive ion chemistry and nanoscale surface modifications are beneficial for enhanced osseointegration of endosseous implants. In this study, a facile synthesis approach to the incorporation of bioactive Ca(2+) ions into the interlayers of nanoporous structures (Ca-nano) formed on a Ti6Al4V alloy surface was developed by sequential chemical and heat treatments. Samples with a machined surface and an Na(+) ion-incorporated nanoporous surface (Na-nano) fabricated by concentrated alkali and heat treatment were used in parallel for comparison...
2017: International Journal of Nanomedicine
https://www.readbyqxmd.com/read/28183659/basic-evaluation-of-typical-nanoporous-silica-nanoparticles-in-being-drug-carrier-structure-wettability-and-hemolysis
#19
Jing Li, Yingyu Guo
Herein, the present work devoted to study the basic capacity of nanoporous silica nanoparticles in being drug carrier that covered structure, wettability and hemolysis so as to provide crucial evaluation. Typical nanoporous silica nanoparticles that consist of nanoporous silica nanoparticles (NSN), amino modified nanoporous silica nanoparticles (amino-NSN), carboxyl modified nanoporous silica nanoparticles (carboxyl-NSN) and hierachical nanoporous silica nanoparticles (hierachical-NSN) were studied. The results showed that their wettability and hemolysis were closely related to structure and surface modification...
April 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
https://www.readbyqxmd.com/read/28180136/sequencing-of-ebola-virus-genomes-using-nanopore-technology
#20
Thomas Hoenen
Sequencing of virus genomes during disease outbreaks can provide valuable information for diagnostics, epidemiology, and evaluation of potential countermeasures. However, particularly in remote areas logistical and technical challenges can be significant. Nanopore sequencing provides an alternative to classical Sanger and next-generation sequencing methods, and was successfully used under outbreak conditions (Hoenen et al., 2016; Quick et al., 2016). Here we describe a protocol used for sequencing of Ebola virus under outbreak conditions using Nanopore technology, which we successfully implemented at the CDC/NIH diagnostic laboratory (de Wit et al...
November 5, 2016: Bio-protocol
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