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Chuan Cheng, Lukas Lührs, Tobias Krekeler, Martin Ritter, Jörg Weissmüller
Nanoporous metallic actuators for artificial muscle applications are distinguished by combining the low operating voltage which is otherwise reserved for polymer-based actuators with interesting values of strain amplitude, strength and stiffness that are comparable of those of piezoceramics. We report a nanoporous metal actuator with enhanced strain amplitude and accelerated switching. Our 3D macroscopic metallic muscle has semi-ordered and hierarchical nanoporous structure, in which µm-sized tubes align perpendicular with the sample surface, while nm-sized ligaments consist of the tube walls...
July 24, 2017: Nano Letters
Xiaohuan Zang, Weiqian Liang, Qingyun Chang, Tong Wu, Chun Wang, Zhi Wang
Some harmful volatile organic compounds (VOCs), such as methylbenzene, ethylbenzene, xylene, chlorobenzene and bromobenzene, are the commonly found chemicals in pen inks. In this work, a dynamic headspace needle-trap device (D-HS-NTD) with a ZIF-8-derived nanoporous carbon (ZIF-8-NPC) as the adsorbent was developed for the extraction of some VOCs in different pen inks prior to GC-MS detection. The main important influencing experimental parameters including the flow rate of the purge gas N2, extraction temperature, extraction time, desorption temperature and desorption time for the extraction were optimized to obtain a high extraction efficiency...
July 11, 2017: Journal of Chromatography. A
Meng-Bo Luo, Dessalegne A Tsehay, Li-Zhen Sun
The forced translocation of a polymer chain through repulsive nanopores was studied by using Langevin dynamics simulations. The polymer is in the compact globule state at low temperature and in the random coil state at high temperature. Simulation results show that the mean translocation time 〈τ〉 is highly dependent on the temperature T and the minimal 〈τ〉 is located near the coil-globule transition temperature. Moreover, the scaling behaviors 〈τ〉 ∼ N(α) and 〈τ〉 ∼ F(-δ) are studied, with N the polymer length and F the driving force inside the nanopore...
July 21, 2017: Journal of Chemical Physics
Hong Hu, Cheng Xu, Yang Zhao, Kirk J Ziegler, J N Chung
All power production, refrigeration, and advanced electronic systems depend on efficient heat transfer mechanisms for achieving high power density and best system efficiency. Breakthrough advancement in boiling and quenching phase-change heat transfer processes by nanoscale surface texturing can lead to higher energy transfer efficiencies, substantial energy savings, and global reduction in greenhouse gas emissions. This paper reports breakthrough advancements on both fronts of boiling and quenching. The critical heat flux (CHF) in boiling and the Leidenfrost point temperature (LPT) in quenching are the bottlenecks to the heat transfer advancements...
July 21, 2017: Scientific Reports
Alina Asandei, Andrei Ciuca, Aurelia Apetrei, Irina Schiopu, Loredana Mereuta, Chang Ho Seo, Yoonkyung Park, Tudor Luchian
Herein, we describe at uni-molecular level the interactions between poly(amidoamine) (PAMAM) dendrimers of generation 1 and the α-hemolysin protein nanopore, at acidic and neutral pH, and ionic strengths of 0.5 M and 1 M KCl, via single-molecule electrical recordings. The results indicate that kinetics of dendrimer-α-hemolysin reversible interactions is faster at neutral as compared to acidic pH, and we propose as a putative explanation the fine interplay among conformational and rigidity changes on the dendrimer structure, and the ionization state of the dendrimer and the α-hemolysin...
July 21, 2017: Scientific Reports
Bo Bao, Jason Riordon, Farshid Mostowfi, David Sinton
Microfluidic systems that leverage unique micro-scale phenomena have been developed to provide rapid, accurate and robust analysis, predominantly for biomedical applications. These attributes, in addition to the ability to access high temperatures and pressures, have motivated recent expanded applications in phase measurements relevant to industrial CO2, oil and gas applications. We here present a comprehensive review of this exciting new field, separating microfluidic and nanofluidic approaches. Microfluidics is practical, and provides similar phase properties analysis to established bulk methods with advantages in speed, control and sample size...
July 21, 2017: Lab on a Chip
Igor Bodrenko, Jiajun Wang, Samuele Salis, Mathias Winterhalter, Matteo Ceccarelli
To quantify small molecule penetration into and eventually permeation through nanopores, we applied an improved excess-noise analysis of the ion current fluctuation caused by entering molecules. The kinetic parameters of substrate entry and leave are derived from a two-state Markov model, analyzing the substrate concentration depen- dence of the average ion current and its variance. Including filter corrections allows one to detect the transition rates beyond the cutoff frequency, fc, of the instrumental ion-current filter...
July 21, 2017: ACS Sensors
Kai Tian, Ruicheng Shi, Amy Gu, Michael Pennella, Li-Qun Gu
MicroRNAs (miRNAs) are a class of noncoding RNAs that are being explored as a new type of disease biomarkers. The nanopore single-molecule sensor offers a potential noninvasive tool to detect miRNAs for diagnostics and prognosis applications. However, one of the challenges that limits its clinical applications is the presence of a large variety of nontarget nucleic acids in the biofluid extracts. Upon interacting with the nanopore, nontarget nucleic acids produce "contaminative" nanopore signals that interfere with target miRNA discrimination, thus severely lowering the accuracy in target miRNA detection...
2017: Methods in Molecular Biology
Raúl Guerrero-Avilés, Walter Orellana
The energetics and diffusion of water molecules and hydrated ions (Na(+), Cl(-)) passing through nanopores in graphene are addressed by dispersion-corrected density functional theory calculations and ab initio molecular dynamics (MD) simulations. Pores of about 0.8 nm in diameter with different pore-edge passivations, with (H) and (O, H) atoms, were considered. Our MD simulations show a water flux through the hydroxylated pores of about one H2O molecule every three picoseconds, in close agreement with recent experiments that estimated a water flux of three molecules per picosecond through pores of ∼1 nm...
July 21, 2017: Physical Chemistry Chemical Physics: PCCP
Dainelys Guadarrama Bello, Aurélien Fouillen, Antonella Badia, Antonio Nanci
While topography is a key determinant of the cellular response to biomaterials the mechanisms implicated in the cell-surface interactions are complex and still not fully elucidated. In this context, we have examined the effect of nanoscale topography on the formation of filopodia, focal adhesions, and on gene expression of proteins associated with cell adhesion and sensing. Commercially pure titanium discs were treated for oxidative nanopatterning with a solution of H2SO4/H2O2 50:50 (v/v). Scanning electron microscopy and atomic force microscopy characterizations showed that this facile chemical treatment efficiently creates a unique nanoporous surface with a root-mean-square roughness of 11...
July 17, 2017: Acta Biomaterialia
Nitin Shingne, Markus Geuss, Thomas Thurn-Albrecht, Hans-Werner Schmidt, Carmen Mijangos, Martin Steinhart, Jaime Martin
Because final properties of nanoscale polymeric structures are largely determined by the solid-state microstructure of the confined polymer, it is imperative not only to understand how the microstructure of polymers develops under nanoscale confinement but also to establish means to manipulate it. Here we present a series of processing strategies, adapted from methods used in bulk polymer processing, that allow to control the solidification of polymer materials confined in the nanopores of anodic aluminium oxide (AAO) templates...
July 20, 2017: Journal of Physical Chemistry. B
Lei Wang, Shengcai Zhu, Meikun Shen, Haiwen Tian, Songhai Xie, Hongbin Zhang, Yahong Zhang, Yi Tang
Screw dislocation structure in crystal are origin of symmetry breaking in a wide range of dense phase crystals. Preparation of such analogous structure in framework phase crystals is of great importance in zeolites but still a challenge. On the basis of crystal structure-solving and model building, we found that the two specific intergrowths in MTW zeolite produce this complex fractal and spiral structure. With the structure determined parameters (spiral pitch h, screw angle θ and spatial angle ψ) of Burgers circuit, the screw dislocation structure can be constructed by two different dimensional intergrowth sections...
July 20, 2017: Angewandte Chemie
Chao Fang, Rui Qiao
The imbibition of liquids into nanopores plays a critical role in numerous applications, and most prior studies focused on imbibition due to capillary flows. Here we report molecular simulations of the imbibition of water into single mica nanopores filled with pressurized gas. We show that, while capillary flow is suppressed by the high gas pressure, water is imbibed into the nanopore through surface hydration in the form of monolayer liquid films. As the imbibition front moves, the water film behind it gradually densifies...
July 20, 2017: Physical Chemistry Chemical Physics: PCCP
Matthew Pevarnik, Weibin Cui, Sukru Yemenicioglu, Justin Rofeh, Luke Theogarajan
Voltage gating is essential to the computational ability of neurons. We show this effect can be mimicked in a solid-state nanopore by functionalizing the pore interior with a redox active molecule. We study the integration of an active biological molecule, a quinone, into a solid state nanopore and its subsequent induced voltage gating. We show that the voltage gating effect mimics biological gating systems in its classic sigmoidal voltage response, unlike previous synthetic voltage gating systems. Initially the quinone undergoes a reduction due to radicals in the bulk solution and is converted to the hydroquinone state...
July 20, 2017: Bioinspiration & Biomimetics
Xiu Tang, Jia-Hui Zhao, Yu-Han Li, Zi-Ji Zhou, Kui Li, Fu-Tian Liu, Ya-Qian Lan
Nanoporous Co-doped Zn1-xCdxS were facilely fabricated via adopting ZIFs as templates, and Cd(NO3)2 and thiourea as precursors. The highly porous microstructure and uniform Co-doping of the photocatalyst afford a high H2-production rate (45.2 and 422.2 times larger than those of Zn0.5Cd0.5S and CdS), providing an effective way for the development of high performance nanoporous photocatalysts.
July 20, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
L E Ocola, V Sampathkumar, N Kasthuri, R P Winarski
We show that using infiltration of ZnO metal oxide can be useful for high resolution imaging of biological samples in electron and X-ray microscopy. The method is compatible with standard fixation techniques that leave the sample dry, such as finishing with super critical CO2 drying, or simple vacuum drying up to 95 °C. We demonstrate this technique can be applied on tooth and brain tissue samples. We also show that high resolution X-ray tomography can be performed on biological systems using Zn K edge (1s) absorption to enhance internal structures, and obtained the first nanoscale 10 KeV X-ray absorption images of the interior regions of a tooth...
July 19, 2017: Scientific Reports
Jingjie Sha, Hongjiao Shi, Yin Zhang, Chen Chen, Lei Liu, Yunfei Chen
As the single molecule detection tool, solid-state nanopores are being applied in more and more fields, such as medicine controlled delivery, ion conductance microscopes, nanosensors, and DNA sequencing. The critical information obtained from nanopores is the signal collected, which is the ionic block current caused by the molecules passing through the pores. However, the information collected is, in part, impeded by the relatively low signal-to-noise ratio of the current solid-state nanopore measurements. Here, we report that using a salt gradient across the nanopore could improve the signal-to-noise ratio when molecules translocate through Si3N4 nanopore...
April 28, 2017: ACS Sensors
Yoshifumi Oya, Kenji Hata, Tomonori Ohba
We present the structures of NaCl aqueous solution in carbon nanotubes with diameters of 1, 2, and 3 nm based on an analysis performed using X-ray diffraction and canonical ensemble Monte Carlo simulations. Anomalously longer nearest-neighbor distances were observed in the electrolyte for the 1-nm-diameter carbon nanotubes; in contrast, in the 2 and 3 nm carbon nanotubes, the nearest-neighbor distances were shorter than those in the bulk electrolyte. We also observed similar properties for water in carbon nanotubes, which was expected because the main component of the electrolyte was water...
July 19, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Chenyu Wen, Shuangshuang Zeng, Kai Arstila, Timo Sajavaara, Yu Zhu, Zhen Zhang, Shi-Li Zhang
Nanopore technology has been extensively investigated for analysis of biomolecules, and a success story in this field concerns DNA sequencing using a nanopore chip featuring an array of hundreds of biological nanopores (BioNs). Solid-state nanopores (SSNs) have been explored to attain longer lifetime and higher integration density than what BioNs can offer, but SSNs are generally considered to generate higher noise whose origin remains to be confirmed. Here, we systematically study low-frequency (including thermal and flicker) noise characteristics of SSNs measuring 7 to 200 nm in diameter drilled through a 20-nm-thick SiNx membrane by focused ion milling...
February 24, 2017: ACS Sensors
Sana Rauf, Ling Zhang, Asghar Ali, Yang Liu, Jinghong Li
Detection of very low amounts of illicit drugs such as cocaine in clinical fluids like serum continues to be important for many areas in the fight against drug trafficking. Herein, we constructed a label-free nanopore biosensor for rapid and highly sensitive detection of cocaine in human serum and saliva samples based on target-induced strand release strategy. In this bioassay, an aptamer for cocaine was prehybridized with a short complementary DNA. Owing to cocaine specific binding with aptamer, the short DNA strand was displaced from aptamer and translocation of this output DNA through α-hemolysin nanopore generated distinct spike-like current blockages...
February 24, 2017: ACS Sensors
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