Assembling semiconducting molecules by covalent attachment to a lamellar crystalline polymer substrate

• Rainhard Machatschek,
• Patrick Ortmann,
• Renate Reiter,
• Stefan Mecking and
• Günter Reiter

Beilstein J. Nanotechnol. 2016, 7, 784–798, doi:10.3762/bjnano.7.70

• semiconducting molecules. Results Nanocrystal analysis by AFM The model of an ideal CPE45 nanocrystal Nanocrystal dispersions were prepared via nanoprecipitation with the impact of shear forces generated by ultrasonication. By cryo-transmission electron microscopy (TEM) studies on the dispersions, a thickness of

Tight junction between endothelial cells: the interaction between nanoparticles and blood vessels

• Yue Zhang and
• Wan-Xi Yang

Beilstein J. Nanotechnol. 2016, 7, 675–684, doi:10.3762/bjnano.7.60

• blood vessels, which are the sites of phosphorylation of tight junction proteins (claudins, occludins, and ZO (Zonula occludens)) proteins, oxidative stress and shear stress. We propose a connection between the presence of nanoparticles and the regulation of the tight junction, which might be the key

• : (1) phosphorylation, (2) expression level of occludins and (3) shear stress. Research about the phosphorylation of occludins in rat brain capillaries after embolism showed that an increased level of tyrosine phosphorylation in occludins might play an important role regarding the disruption of the

• bile duct ligation researchers suggested a relationship between the time-dependent down-regulation of the occludin expression and a time-dependent increase of superoxide radical levels in the brain [68]. Another factor, shear stress, different from normal stressors, exerts a perpendicular force on the

In situ observation of deformation processes in nanocrystalline face-centered cubic metals

• Aaron Kobler,
• Christian Brandl,
• Horst Hahn and
• Christian Kübel

Beilstein J. Nanotechnol. 2016, 7, 572–580, doi:10.3762/bjnano.7.50

• additional local deviations from the sample bending, which appear as local, distinct rotations within the crystallites and in the vicinity of the grain boundaries (examples indicated by black boxes). A mismatch of the relative lattice rotation of neighboring grains needs to be accommodated as a shear

• deformation across the GB between the crystallites. The small angle rotation discontinuity at the grain boundary directly shows the operation of GB deformation processes, such as GB sliding and/or shear coupled GB motion. The small angle crystallite rotation highlighted in Figure 5b,c even shows the partial

Nanoscale effects in the characterization of viscoelastic materials with atomic force microscopy: coupling of a quasi-three-dimensional standard linear solid model with in-plane surface interactions

• Santiago D. Solares

Beilstein J. Nanotechnol. 2016, 7, 554–571, doi:10.3762/bjnano.7.49

• -mode using a single oscillation frequency in the small-amplitude regime. However, even in these most ideal situations, there still exist challenges associated with the shape of the tip, which does not necessarily impart uniform compressive strain, but may cause both compressive and shear strains with

• subsurface only considers tensile (compressive) strains, thus neglecting shear. This is common practice in AFM simulation, where 1D models are the norm (e.g., [2][3][10][12][13][14][16][28]), but neglects the fact that indentation of the tip into a soft material introduces surface curvature and subsurface 3D

Free vibration of functionally graded carbon-nanotube-reinforced composite plates with cutout

• Mostafa Mirzaei and
• Yaser Kiani

Beilstein J. Nanotechnol. 2016, 7, 511–523, doi:10.3762/bjnano.7.45

• analysis of CNTRC structures, examines the free vibration characteristics of plates containing a cutout that are reinforced with uniform or nonuniform distribution of carbon nanotubes. The first-order shear deformation plate theory is used to estimate the kinematics of the plate. The solution method is

• vibration and static response of laminated plates with FG-CNTRC layers using a mixed Navier-layerwise differential quadrature method. In this research, plates with all edges simply supported are considered. Natarajan et al. [12] applied a higher order shear and normal deformable plate formulation to study

• approach may be modified with the introduction of the efficiency parameters. Under such modification, Young’s modulus and the shear modulus of the composite media take the form: In this formula, the properties of the CNT are denoted by a superscript CN and that those belong to matrix are denoted by a

Contact-free experimental determination of the static flexural spring constant of cantilever sensors using a microfluidic force tool

• John D. Parkin and
• Georg Hähner

Beilstein J. Nanotechnol. 2016, 7, 492–500, doi:10.3762/bjnano.7.43

• experienced by the cantilever is due to plan-view-dependent drag as opposed to viscous shear, and the former is not significantly influenced by the presence of the tip. The reason for the observed hysteresis in the speed-dependent deflection (Figure 5) is not entirely clear. Some cantilevers showed no

Active multi-point microrheology of cytoskeletal networks

• Tobias Paust,
• Tobias Neckernuss,
• Lina Katinka Mertens,
• Ines Martin,
• Michael Beil,
• Paul Walther,
• Thomas Schimmel and
• Othmar Marti

Beilstein J. Nanotechnol. 2016, 7, 484–491, doi:10.3762/bjnano.7.42

• ; Introduction The dynamic shear modulus describes properties of polymer networks. It can be determined by recording and mathematically transforming the thermal motion of a particle embedded in a viscoelastic medium into the frequency domain. Since no external forces are applied to the motion of the particle

• , this method is named passive microrheology [1][2][3][4]. The resulting shear modulus shows the elastic and diffusive behavior of the investigated medium over the frequency range accessible by the measuring setup. This output is the result of different methods handling the unilateral Laplace transform

• [5][6][7]. By exciting a particle with an oscillating force, the shear modulus at a specific frequency can be determined by measuring the response of the particle. The motion of the particle also includes information about the damping and the viscosity of the surrounding medium. This method is known

Plasticity-mediated collapse and recrystallization in hollow copper nanowires: a molecular dynamics simulation

• Amlan Dutta,
• Arup Kumar Raychaudhuri and
• Tanusri Saha-Dasgupta

Beilstein J. Nanotechnol. 2016, 7, 228–235, doi:10.3762/bjnano.7.21

• system. The resolved shear load can thereby exceed the critical limit for producing the Shockley dislocations. The calculated shear-strain map indicates that the partial dislocations nucleate at the inner surface and propagate towards the outer periphery, thereby leaving behind trails of stacking faults

• highlighted, the partial dislocation at the boundary of an abruptly terminated stacking fault moves towards the outer surface and finally disappears during the recovery. Color-coded snapshots indicating the atomic shear strains are also given by the side. Snapshot of the nanostructure at 575 K temperature

Simultaneous cancer control and diagnosis with magnetic nanohybrid materials

• Reza Saadat and
• Franz Renz

Beilstein J. Nanotechnol. 2016, 7, 121–125, doi:10.3762/bjnano.7.14

• hence be assumed that a network (consisting of about three units in all spatial directions) of the MNP was obtained. We assume that bigger cluster units do not appear long enough to be detected due to shear forces destroying them. The cluster units are stable in a pH range from 13 to 4.5. At lower pH

Fabrication and characterization of novel multilayered structures by stereocomplexion of poly(D-lactic acid)/poly(L-lactic acid) and self-assembly of polyelectrolytes

• Elena Dellacasa,
• Li Zhao,
• Gesheng Yang,
• Laura Pastorino and
• Gleb B. Sukhorukov

Beilstein J. Nanotechnol. 2016, 7, 81–90, doi:10.3762/bjnano.7.10

• resonance frequency of the quartz crystal oscillator, A is the area of the electrode (0.205 cm2), ρq is the quartz density (2.648 g/cm3), and µq is its shear modulus (2.947·1011 g/cm·s2). The cleaned electrodes were immersed into aqueous solutions of PSS and PAH (2 mg/mL) for 15 min and PLL (5 mg/mL) for 30

Large area scanning probe microscope in ultra-high vacuum demonstrated for electrostatic force measurements on high-voltage devices

• Urs Gysin,
• Thilo Glatzel,
• Thomas Schmölzer,
• Adolf Schöner,
• Sergey Reshanov,
• Holger Bartolf and
• Ernst Meyer

Beilstein J. Nanotechnol. 2015, 6, 2485–2497, doi:10.3762/bjnano.6.258

• presents a computer aided design (CAD) image of the beam deflection unit. The red arrows indicate the directions of motion of the adjustable parts of the unit. To align the beam of light onto the free end of the oscillating cantilever several shear piezo actuators allow for the movement of parts within the

• beam deflection unit. The focusing optics is placed on two shear piezo elements in order to allow for horizontal movement and to adjust the light beam across the width of the cantilever. Additionally, the beam splitter is placed on two shear piezo elements rotating the beam splitter and therefore align

• the light beam along the long axis of the cantilever. The reflected light from the cantilever irradiates directly onto the PSD with an adapted current to voltage converter (IV-converter). The detection unit, consisting of the PSD and IV-converter, may be moved by three 2D shear piezo elements

Electroviscous effect on fluid drag in a microchannel with large zeta potential

• Dalei Jing and
• Bharat Bhushan

Beilstein J. Nanotechnol. 2015, 6, 2207–2216, doi:10.3762/bjnano.6.226

• ][14][15][16]. To characterize the EDL, zeta potential is defined, and it refers to the electrical potential at the shear plane separating the immobile fluid layer strongly attracted to the solid surface from the rest of the liquid. The magnitude of zeta potential is reported to be up to several

Lower nanometer-scale size limit for the deformation of a metallic glass by shear transformations revealed by quantitative AFM indentation

• Arnaud Caron and
• Roland Bennewitz

Beilstein J. Nanotechnol. 2015, 6, 1721–1732, doi:10.3762/bjnano.6.176

• not discrete but continuous and localized around the indenter, and does not exhibit rate dependence. This contrasts with the observation of serrated, rate-dependent flow of metallic glasses at larger scales. Our results reveal a lower size limit for metallic glasses below which shear transformation

• mechanisms are not activated by indentation. In the case of metallic glass, we conclude that the energy stored in the stressed volume during nanometer-scale indentation is insufficient to account for the interfacial energy of a shear band in the glassy matrix. Keywords: AFM indentation; dislocation

• ; metallic glasses; metals; plasticity; shear transformation; Introduction Hardness testing has been widely applied by materials scientists and mechanical engineers to assess the mechanical properties of materials and to predict their behavior during machining processes or under tribological loading for the

Possibilities and limitations of advanced transmission electron microscopy for carbon-based nanomaterials

• Xiaoxing Ke,
• Carla Bittencourt and
• Gustaaf Van Tendeloo

Beilstein J. Nanotechnol. 2015, 6, 1541–1557, doi:10.3762/bjnano.6.158

• chirality (Figure 5a), a displacement map can be obtained (Figure 5c–d) at picometer precision, which further reveals the strain distribution. Strain induced by bending can be mapped in two dimensions, and further proposed to be a dominant non-uniform shear strain. The strain in the nanotube is associated

• instance, the evolution of defects (such as the shear strain present in CNTs as discussed in Section 3.1) along with the elastic/plastic deformation in CNT-reinforced composites under load can be well studied using similar techniques [109]. In contrast to the external stimuli, which are introduced through

Electrical characterization of single molecule and Langmuir–Blodgett monomolecular films of a pyridine-terminated oligo(phenylene-ethynylene) derivative

• Henrry M. Osorio,
• Santiago Martín,
• María Carmen López,
• Santiago Marqués-González,
• Simon J. Higgins,
• Richard J. Nichols,
• Paul J. Low and
• Pilar Cea

Beilstein J. Nanotechnol. 2015, 6, 1145–1157, doi:10.3762/bjnano.6.116

• 5 MHz, Δm(g) is the mass change, A is the electrode area, ρq is the density of the quartz (2.65 g·cm-3), μq is the shear modulus (2.95 × 1011 dyn·cm−2), and the molecular weight of 1 is 280 g·mol−1. Thus, the surface coverage of 1 incorporated into LB films, obtained from Equation 1, is 0.98 × 10−9

Nanostructuring of GeTiO amorphous films by pulsed laser irradiation

• Valentin S. Teodorescu,
• Cornel Ghica,
• Adrian V. Maraloiu,
• Mihai Vlaicu,
• Andrei Kuncser,
• Magdalena L. Ciurea,
• Ionel Stavarache,
• Ana M. Lepadatu,
• Nicu D. Scarisoreanu,
• Andreea Andrei,
• Valentin Ion and
• Maria Dinescu

Beilstein J. Nanotechnol. 2015, 6, 893–900, doi:10.3762/bjnano.6.92

• for plastic flow. Such a mechanism can be imagined based on the shear transformation-zone theory of plastic deformation near the glass transition [30]. The temperature due to the laser heating was estimated by using the Heat Flow software [24]. Figure 8 shows the temperature variation at different

Stiffness of sphere–plate contacts at MHz frequencies: dependence on normal load, oscillation amplitude, and ambient medium

• Jana Vlachová,
• Rebekka König and
• Diethelm Johannsmann

Beilstein J. Nanotechnol. 2015, 6, 845–856, doi:10.3762/bjnano.6.87

• can be explained by nanoroughness. In other words, contact splitting (i.e., a transport of shear stress across many small contacts, rather than a few large ones) can be exploited to reduce partial slip. Keywords: contact mechanics; contact splitting; contact stiffness; partial slip; quartz crystal

• be tested easily. The experiments were undertaken with a quartz crystal microbalance (QCM). The QCM is mostly known as a device for thickness determination, but it can equally well be employed to measure contact stiffness. In this regard, it is helpful to view the QCM as a shear wave reflectometer

• related to the dissipation factor, D, by D = Γ/(2f). fF is the fundamental frequency, which is often 5 MHz. Zq = 8.8 × 106 kg∙m−2s−1 is the shear wave impedance of AT-cut quartz. is the area-averaged complex amplitude of the tangential stress at the resonator surface, and u0 is the amplitude of

Entropy effects in the collective dynamic behavior of alkyl monolayers tethered to Si(111)

• Christian Godet

Beilstein J. Nanotechnol. 2015, 6, 583–594, doi:10.3762/bjnano.6.60

• dissipation mechanisms is the behavior of tethered OML under compressive and shear forces, as found in nano-tribology experiments, where external forces can cause conformational changes. Again, a disorder gradient results from the formation of gauche defects which can be reverted when the atomic force

• excitations collected from a thermal bath. c) The applied bias dependence of activation energies is tentatively related to compression and shear stresses expected for an OML considered as a continuous medium submitted to a compressive force (Figure 1) [49]. Finally, on the basis of the bias dependence of the

• point" temperature TF should decrease with increasing n-alkane length. OML mechanics: compressive and shear forces In this section, the molecular layer is considered as a continuous medium submitted to a compressive electrostatic pressure, proportional to VI2, where VI is the potential drop across the

Influence of grain size and composition, topology and excess free volume on the deformation behavior of Cu–Zr nanoglasses

• Daniel Şopu and
• Karsten Albe

Beilstein J. Nanotechnol. 2015, 6, 537–545, doi:10.3762/bjnano.6.56

• from a homogeneous to an inhomogeneous plastic deformation, because the softer interfaces are promoting the formation shear transformation zones. In case of the Cu-rich system, shear localization at the interfaces is most pronounced, since both the topological order and free volume content of the

• interfaces don’t show topological disorder. Our results provide clear evidence that the mechanical properties of metallic NGs can be systematically tuned by controlling the size and the chemical composition of the glassy nanograins. Keywords: enhanced plasticity; metallic glasses; nanoglasses; shear bands

• annihilation spectroscopy [9], while molecular dynamics studies showed that glass–glass interfaces exhibit an excess free volume and a modified local order [10][11]. If plastically deformed, the soft glass in the interfaces promotes shear band nucleation similar to the effect of residual shear bands in pre

Filling of carbon nanotubes and nanofibres

• Reece D. Gately and
• Marc in het Panhuis

Beilstein J. Nanotechnol. 2015, 6, 508–516, doi:10.3762/bjnano.6.53

• removal of the encapsulated nanoparticles [95]. Sonication has also been employed to fill MWCNTs in solution. Sonication acted to shear the MWCNT, resulting in the filling of the MWCNT with the surrounding metal solution [96]. Other methods have employed focused electron irradiation to produce SWCNTs

A scanning probe microscope for magnetoresistive cantilevers utilizing a nested scanner design for large-area scans

• Tobias Meier,
• Alexander Förste,
• Ali Tavassolizadeh,
• Karsten Rott,
• Dirk Meyners,
• Roland Gröger,
• Günter Reiss,
• Eckhard Quandt,
• Thomas Schimmel and
• Hendrik Hölscher

Beilstein J. Nanotechnol. 2015, 6, 451–461, doi:10.3762/bjnano.6.46

• while holding the large-area scanner at a fixed position. The high resolution open-loop scanner is thereby mounted on a large-area scan stage. The high resolution scanner was realized by using a stack of shear actors for x–y scanning and a stack piezo actor with a travel of 5 μm and a resonance

A surface acoustic wave-driven micropump for particle uptake investigation under physiological flow conditions in very small volumes

• Florian G. Strobl,
• Dominik Breyer,
• Phillip Link,
• Adriano A. Torrano,
• Christoph Bräuchle,
• Matthias F. Schneider and
• Achim Wixforth

Beilstein J. Nanotechnol. 2015, 6, 414–419, doi:10.3762/bjnano.6.41

• uptake of nanoparticles. Here, we present a versatile microfluidic device based on acoustic streaming induced by surface acoustic waves (SAWs). The device offers a convenient method for introducing fluid motion in standard cell culture chambers and for mimicking capillary blood flow. We show that shear

• physiological flow conditions the particle uptake rates for this system are significantly lower than at low shear conditions. This underlines the vital importance of the fluidic environment for cellular uptake mechanisms. Keywords: acoustic streaming; cellular uptake; flow; nanoparticles; sedimentation; shear

• Cloc > Cm. Ignoring these effects can in fact lead to misinterpretation of experimental data, especially to an overestimation of the impact of big particles or agglomerates. Furthermore, particles on a cell surface under shear are subject to drag and torsion forces [3]. For spherical particles in the

The fate of a designed protein corona on nanoparticles in vitro and in vivo

• Denise Bargheer,
• Julius Nielsen,
• Gabriella Gébel,
• Markus Heine,
• Sunhild C. Salmen,
• Roland Stauber,
• Horst Weller,
• Joerg Heeren and
• Peter Nielsen

Beilstein J. Nanotechnol. 2015, 6, 36–46, doi:10.3762/bjnano.6.5

• of particles <10 nm is more and more balanced by shear forces due to Brownian motion with the consequence of detachment of proteins. The authors explained their finding with a heteroaggregation model in which a low number of SPIOs is stabilized between layers of proteins. In our FPLC study we do not

Intake of silica nanoparticles by giant lipid vesicles: influence of particle size and thermodynamic membrane state

• Florian G. Strobl,
• Florian Seitz,
• Christoph Westerhausen,
• Armin Reller,
• Adriano A. Torrano,
• Christoph Bräuchle,
• Achim Wixforth and
• Matthias F. Schneider

Beilstein J. Nanotechnol. 2014, 5, 2468–2478, doi:10.3762/bjnano.5.256

• and the release of cargo from giant vesicles was also the subject of earlier works in our group [35][36]. Due to the non-zero lateral shear resistance of gel-phase membranes, the relaxation time for the healing of defects will be much longer as compared to liquid membranes. Hence, induced pores remain

Aquatic versus terrestrial attachment: Water makes a difference

• Petra Ditsche and
• Adam P. Summers

Beilstein J. Nanotechnol. 2014, 5, 2424–2439, doi:10.3762/bjnano.5.252

• surfaces. Additional capillary bridges between foot and substrate are formed due to the fluid secreted by the beetle and shear adhesion forces are in the same range as in air [43]. Similar results were described for geckos attaching to hydrophilic surfaces underwater and in air while no significant

• actually the force needed to shear the junctions formed between the surfaces in contact. In contrast, in wet friction a film of water or another liquid is involved. This liquid can originate from humidity in the air or from secretion by the animal. Under such boundary lubrication conditions there is a