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Elaborating an instrumented nanoindentation is to exercise non-destructive tests to be applied to volumes of polymethylmetacrylate (PMMA) materials in miniature. This work focuses on factors that explain the trends variation of mechanical properties like Young's modulus (E), contact hardness (H) and indentation force (P). The evolution of E and H with depth (h) and P shows a 2.77 nm inflection point at low penetrations, separating two zones: the first increasing and the second decreasing. This is respectively explained by the surface hardening induced by preparing the material surface, and the existence of a surface hardness gradient denoted by an indentation size effect (ISE) observed at very low depths. Moreover, In addition, a critical penetration depth of 9.71 nm below which the surface effect dominates the variation of the penetrating load is detected. E and H results differences between dynamic and static modes are 8.46% and 6.44% inducing an overestimation of 35 MPa in E value, and an underestimation of 1.23 MPa in H value. This tends to affect the expected nanoscale precision of the indentation to determine the nanomechanical properties of PMMA.

Highly compacted bentonite is an ideal back-filling (buffer) material for the deep geological disposal of high-level radioactive waste. Montmorillonite is the main constituent mineral of it. The nanoscopic swelling characteristic of montmorillonite mineral particles greatly influences the macroscopic buffering performance of highly compacted bentonite blocks. Firstly, the montmorillonite suspension liquid was exfoliated by freeze-thaw cycles, the appropriate mineral particles were selected by atomic force microscope (AFM) for making colloidal probes. Then, the swelling pressure between mineral particles was measured by AFM, investigating the effects of interlayer distance, layer number, temperature, and interlayer cation type on the nanoscale swelling pressure. The experimental results showed that the swelling pressure of montmorillonite mineral particles peaks at about 0.7–0.8 nm interlayer distance. The swelling pressure of mineral particles with more layers is smaller. The higher the ambient temperature, the greater the swelling pressure. The swelling pressure of Ca-montmorillonite is significantly larger than that of Na-montmorillonite. The Laird model has a relatively good applicability with the interlayer distance of 0.6–1.2 nm; the DLVO theory has a good applicability with the interlayer distance greater than 1.5 nm. Finally, a predictive model was developed for the swelling pressure of nanoscopic mineral particles considering the effect of layer number. The research results provide data support and theoretical support for swelling pressure generation and cross-scale transmission mechanism of highly compacted bentonite hydration. • An experimental method for nanoscale swelling pressure of montmorillonite minerals. • The swelling characteristics of montmorillonite quasicrystals in nanoscale. • The applicability of nanoscale swelling theoretical models to montmorillonite minerals. • The swelling pressure prediction model of montmorillonite minerals during hydration. [ABSTRACT FROM AUTHOR]

Phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2) is generated through phosphorylation of phosphatidylinositol 4-phosphate (PtdIns(4)P) by Mss4p, the only PtdIns phosphate 5-kinase in yeast cells. PtdIns(4,5)P2 is involved in various kinds of yeast functions. PtdIns(4)P is not only the immediate precursor of PtdIns(4,5)P2, but also an essential signaling molecule in the plasma membrane, Golgi, and endosomal system. To analyze the distribution of PtdIns(4,5)P2 and PtdIns(4)P in the yeast plasma membrane at a nanoscale level, we employed a freeze–fracture electron microscopy (EM) method that physically immobilizes lipid molecules in situ. It has been reported that the plasma membrane of budding yeast can be divided into three distinct areas: furrowed, hexagonal, and undifferentiated flat. Previously, using the freeze–fracture EM method, we determined that PtdIns(4)P is localized in the undifferentiated flat area, avoiding the furrowed and hexagonal areas of the plasma membrane. In the present study, we found that PtdIns(4,5)P2 was localized in the cytoplasmic leaflet of the plasma membrane, and concentrated in the furrowed area. There are three types of PtdIns 4-kinases which are encoded by stt4, pik1, and lsb6. The labeling density of PtdIns(4)P in the plasma membrane significantly decreased in both pik1ts and stt4ts mutants. However, the labeling densities of PtdIns(4,5)P2 in the plasma membrane of both the pik1ts and stt4ts mutants were comparable to that of the wild type yeast. These results suggest that PtdIns(4)P produced by either Pik1p or Stt4p is immediately phosphorylated by Mss4p and converted to PtdIns(4,5)P2 at the plasma membrane. [ABSTRACT FROM AUTHOR]

Membrane microdomains or rafts, sterol- and sphingolipid-rich microdomains in the plasma membrane have been studied extensively in mammalian cells. Recently, rafts were found to mediate virulence in a variety of parasites, including Toxoplasma gondii. However, it has been difficult to examine a two-dimensional distribution of lipid molecules at a nanometer scale. We tried to determine the distribution of glycosphingolipids GM1 and GM3, putative raft components in the T. gondii cell membrane in this study, using a rapid-frozen and freeze-fractured immuno-electron microscopy method. This method physically stabilized molecules in situ, to minimize the probability of artefactual disruption. Labeling of GM3, but not GM1, was observed in the exoplasmic (or luminal), but not the cytoplasmic, leaflet of the inner membrane complex (IMC) in T. gondii infected in human foreskin fibroblast-1 (HFF-1). No labeling was detected in any leaflet of the T. gondii plasma membrane. In contrast to HFF-1, T. gondii infected in mouse fibroblast (MF), labelings of both GM1 and GM3 were detected in the IMC luminal leaflet, although GM1′s gold labeling density was very low. The same freeze-fracture EM method showed that both GM1 and GM3 were expressed in the exoplasmic leaflet of the MF plasma membrane. However, labeling of only GM3, but not GM1, was detected in the exoplasmic leaflet of the HFF-1 plasma membrane. These results suggest that GM1 or GM3, localized in the IMC, is obtained from the plasma membranes of infected host mammalian cells. Furthermore, the localization of microdomains or rafts in the luminal leaflets of the intracellular confined space IMC organelle of T. gondii suggests a novel characteristic of rafts.

The ability to spatially resolve the chemical distribution of compounds on a surface is important in many applications ranging from biological to material science. To this extent, we have recently introduced a hybrid atomic force microscopy (AFM)-mass spectrometry (MS) system for direct thermal desorption and pyrolysis of material with nanoscale chemical resolution. However, spatially resolved direct surface heating using local thermal desorption becomes challenging on material surfaces with low melting points, because the material will undergo a melting phase transition due to heat dissipation prior to onset of thermal desorption. Therefore, we developed an approach using mechanical sampling and collection of surface materials on an AFM cantilever probe tip for real-time analysis directly from the AFM tip. This approach allows for material to be concentrated directly onto the probe for subsequent MS analysis. We evaluate the performance metrics of the technique and demonstrate localized MS sampling from a candelilla wax matrix containing UV stabilizers avobenzone and oxinoxate from areas down to 250 nm × 250 nm. Overall, this approach removes heat dissipation into the bulk material allowing for a faster desorption and concentration of the gas phase analyte from a single heating pulse enabling higher signal levels from a given amount of material in a single sampling spot. Graphical abstract [ABSTRACT FROM AUTHOR]

Elaborating an instrumented nanoindentation is to exercise nondestructive tests to be applied to volumes of polymethylmetacrylate (PMMA) materials in miniature. This work focuses on factors that explain the trends variation of mechanical properties like Young's modulus (E), contact hardness (H) and indentation force (P). The evolution of E and H with depth (h) and P shows a 2.77 nm inflection point at low penetrations, separating two zones: the first increasing and the second decreasing. This is respectively explained by the surface hardening induced by preparing the material surface, and the existence of a surface hardness gradient denoted by an indentation size effect (ISE) observed at very low depths. Moreover, In addition, a critical penetration depth of 9.71 nm below which the surface effect dominates the variation of the penetrating load is detected. E and H results differences between dynamic and static modes are 8.46% and 6.44% inducing an overestimation of 35 MPa in E value, and an underestimation of 1.23 MPa in H value. This tends to affect the expected nanoscale precision of the indentation to determine the nanomechanical properties of PMMA. [ABSTRACT FROM AUTHOR]

Autophagy is a degradative cellular pathway that protects eukaryotic cells from starvation/stress. Phosphatidylinositol 4-kinases, Pik1p and Stt4p, are indispensable for autophagy in budding yeast, but participation of PtdIns-4 kinases and their product, phosphatidylinositol 4-phosphate [PtdIns(4)P], is not understood. Nanoscale membrane lipid distribution analysis showed PtdIns(4)P is more abundant in yeast autophagosomes in the luminal leaflet than the cytoplasmic leaflet. PtdIns(4)P is confined to the cytoplasmic leaflet of autophagosomal inner and outer membranes in mammalian cells. Using temperature-conditional single PIK1 or STT4 PtdIns 4-kinase mutants, autophagic bodies in the vacuole of PIK1 and STT4 mutant cells dramatically decreased at restrictive temperatures, and the number of autophagosomes in the cytosol of PIK1 mutants cells was also decreased, whereas autophagosome levels of STT4 mutant cells were comparable to that of wild-type and STT4 mutant cells at permissive temperatures. Localization of PtdIns(4)P in the luminal leaflet in the biological membrane is a novel finding, and differences in PtdIns(4)P distribution suggest substantial differences between yeast and mammals. We also demonstrate in this study that Pik1p and Stt4p play essential roles in autophagosome formation and autophagosome–vacuole fusion in yeast cells, respectively. • PtdIns(4)P is localized in the luminal leaflet of the yeast autophagsomal membranes. • PtdIns(4)P localization in yeast autophagosomal membrane is opposite to mammals. • Pik1p plays essential roles in autophagosome formation. • Stt4p is important for the process of autophagosome–vacuole fusion. [ABSTRACT FROM AUTHOR]

Highlights • Comparison of nanosecond and femtosecond laser-induced tip-enhanced ablation. • 3D numeric modeling of laser-induced tip-enhanced ablation. • Chemometrics study of tip-enhanced ablation and ionization time-of-flight mass spectrometry. Abstract Laser-induced tip-enhanced ablation appears to be a promising nanometer-scale sampling approach. Recently we have developed a Near-Field Ablation and Ionization Mass Spectrometer, which is capable of direct ablation and ionization of materials at a scale of tens of nanometers under both nanosecond and femtosecond pulsed lasers. In spite of its great potential as a nanometer-scale sampling source, its underlying mechanism remains to be further explored. To figure out the difference between nanosecond and femtosecond laser-induced tip-enhanced ablations, we developed a three-dimensional theoretical code to explain the ablation phenomena on a Ti-coating sample. With calculated time-evolving and space-distribution features of sample temperature, the simulation justified the time needed to reach electron-lattice thermal equilibrium to be within several picoseconds, and showed that nanosecond laser ablation features much greater thermal effect. We also calculated the theoretical ablated pit profiles and volume after one laser pulse under both lasers. They all fitted well with experimental results. Afterwards, we compared the experimental mass spectra of various salts in the nanosecond and femtosecond laser experiments and studied the roles of properties via chemometrics works. Result again revealed that thermal properties contributed relatively more in the nanosecond laser model. Ionization potential was equally important in both experiments, which met well with the intensity distribution observed in the mass spectra. Moreover, the influences of lattice energy, molar mass and fusion heat were also explained. All these results proved and supported each other, which verifies our study to be reasonable and helps us get a better understanding of this new technique. [ABSTRACT FROM AUTHOR]

Abstract The effect of polyvinyl alcohol, PVA, on crystallite and particle sizes of strontium hexaferrite synthesized by high-energy ball milling followed by an annealing at 950 °C is presented. Results of X-ray diffraction of (100-x)SrFe 12 O 19 @xPVA (0 ≤ x ≤ 100) composites shown the presence of strontium hexaferrite in all samples, while the crystal structure of PVA is degraded due to the mechanical energy supplied from the milling process. However, the Infrared study (FTIR) indicated that the polymeric chain kept intact. Magnetic behavior, from vibrating sample magnetometry tests, shown a waist wasp type hysteresis loop, for all the composites SrFe 12 O 19 @PVA, confirming that both materials do not generate bonds, and there is only a mixture of materials. Finally, Rietveld refinement, SEM analysis, and particle size measurement allowed demonstrating that PVA reduces the crystallite and particle sizes at nanometers scale of strontium hexaferrite synthesized. Highlights • SrFe 12 O 19 @PVA with different ratio were obtained by high energy ball milling using sapphire balls during 3 h. • The effect of mechanical mill in the PVA material is reported. • A magnetic model of SrFe 12 O 19 @PVA wasp waist is proposed. • Nanoparticles of strontium hexaferrite were obtained and liberated in water using PVA as encapsulator. • The best ratio is 25% of PVA and 75% of strontium hexaferrite. [ABSTRACT FROM AUTHOR]

Phosphatidylinositol 4‐phophate (PtdIns(4)P) is an essential signaling molecule in the Golgi body, endosomal system, and plasma membrane and functions in the regulation of membrane trafficking, cytoskeletal organization, lipid metabolism and signal transduction pathways, all mediated by direct interaction with PtdIns(4)P‐binding proteins. PtdIns(4)P was recently reported to have functional roles in autophagosome biogenesis. LC3 and GABARAP subfamilies and a small GTP‐binding protein, Rab7, are localized on autophagosomal membranes and participate at each stage of autophagosome formation and maturation. To better understand autophagosome biogenesis, it is essential to determine the localization of PtdIns(4)P and to examine its relationship with LC3 and GABARAP subfamilies and Rab7. To analyze PtdIns(4)P distribution, we used an electron microscopy technique that labels PtdIns(4)P on the freeze‐fracture replica of intracellular biological membranes, which minimizes the possibility of artificial perturbation because molecules in the membrane are physically immobilized in situ. Using this technique, we found that PtdIns(4)P is localized on the cytoplasmic, but not the luminal (exoplasmic), leaflet of the inner and outer membranes of autophagosomes. Double labeling revealed that PtdIns(4)P mostly colocalizes with Rab7, but not with LC3B, GABARAP, GABARAPL1 and GABARAPL2. Rab7 plays essential roles in autophagosome maturation and in autophagosome‐lysosome fusion events. We suggest that PtdIns(4)P is localized to the cytoplasmic leaflet of the autophagosome at later stages, which may illuminate the importance of PtdIns(4)P at the later stages of autophagosome formation. Quick‐freezing and freeze‐fracture replica labeling method revealed that phosphatidylinositol 4‐phosphate (PtdIns(4)P) was localized on the cytoplasmic leaflet in the inner and outer membranes of the autophagosome in the Torin1‐treated autophagy‐induced Huh7 cells. PtdIns(4)P was colocalized with Rab7, but not LC3B, GABARAP, GABARAPL1 or GABARAPL2 on the autophagosomal membranes. Rab7 was reported to play essential roles for the maturation of autophagosome formation, suggesting that PtdIns(4)P appears with Rab7 at the later and mature stages of autophagosome formation. [ABSTRACT FROM AUTHOR]

Highlights • Current developments of nanoscale insight into passive oxide films. • Cr(III) enrichment and its homogeneity at the nanoscale in passive films. • Corrosion properties of grain boundaries in early intergranular corrosion. • Interaction of organic inhibitor molecules with passivated metallic surfaces. Abstract Oxide passive films are a key for the durability of metals and alloys components as well as a central issue in corrosion science and engineering. Herein, we discuss current developments of the nanometer and sub-nanometer scale knowledge of the barrier properties and adsorption properties of passive oxide films brought by recent model experimental and theoretical investigations. The discussed aspects include (i) the chromium enrichment and its homogeneity at the nanoscale in passive films formed on Cr-bearing alloys such as stainless steel, (ii) the corrosion properties of grain boundaries in early intergranular corrosion before penetration and propagation in the grain boundary network, and (iii) the interaction of organic inhibitor molecules with incompletely passivated metallic surfaces. In all three cases, key issues are highlighted and future developments that we consider as most relevant are identified. [ABSTRACT FROM AUTHOR]

Phosphatidylinositol 4-phosphate (PtdIns(4)P) is the immediate precursor of phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P 2 ), which is located on the cytoplasmic leaflet of the plasma membrane and has been reported to possess multiple cellular functions. Although PtdIns(4)P and PtdIns(4,5)P 2 have been reported to localize to multiple intracellular compartments and to each function as regulatory molecules, their generation, regulation and functions in most intracellular compartments are not well-defined. To analyze PtdIns(4)P and PtdIns(4,5)P 2 distributions, at a nanoscale, we employed an electron microscopy technique that specifically labels PtdIns(4)P and PtdIns(4,5)P 2 on the freeze-fracture replica of intracellular biological membranes. This method minimizes the possibility of artificial perturbation, because molecules in the membrane are physically immobilized in situ . Using this technique, we found that PtdIns(4)P was localized to the cytoplasmic leaflet of Golgi apparatus and vesicular-shaped structures. The PtdIns(4,5)P 2 labeling was observed in the cytoplasmic leaflet of the mitochondrial inner membrane and vesicular-shaped structures. Double labeling of PtdIns(4)P and PtdIns(4,5)P 2 with endosome markers illustrated that PtdIns(4)P and PtdIns(4,5)P 2 were mainly localized to the late endosome/lysosome and early endosome, respectively. PtdIns(4)P and PtdIns(4,5)P 2 were colocalized in some endosomes, with the two phospholipids separated into distinct microdomains on the same endosomes. This is the first report showing, at a nanoscale, segregation of PtdIns(4)P- and PtdIns(4,5)P 2 -enriched microdomains in the endosome, of likely importance for endosome functionality. [ABSTRACT FROM AUTHOR]

In order to investigate the crack initiation from the interface edge caused by nanometer scale plastic stress intensity, we conduct in situ mechanical bending experiments by using nano-cantilever specimens. The large-scale yielding (LSY) condition is successfully established in all nano-cantilever specimens, and fully plastic deformation governs the region near the interface edge where the crack initiates. The results show that, under the LSY condition, the stress distribution near the interface edge possesses the r - λ P -type singularity with the same λ P = 0.14 among all specimens. An extremely small plastic singular stress field of only 13 nm is experimentally yielded, within which the critical plastic stress intensity parameter is approximately determined as K PC = 82 MPa m 0.14 . This indicates that the plastic singular stress field of 13 nm still governs the crack initiation from the interface edge, indicating the validity of the conventional fracture mechanics at such a nanometer scale. [ABSTRACT FROM AUTHOR]

Chain rule plays an important role in fractional calculus. There are many definitions of fractional derivative, and this paper shows that the chain rule is invalid for Jumarie's modification of Riemann-Liouville definition. [ABSTRACT FROM AUTHOR]

We propose and have tested a method of determining linear thermal expansion coefficients, which is not affected by the influence of thermal deformation of structural elements of the measuring system on the results determining these coefficients. We present recommendations for the application of the developed methodology. [ABSTRACT FROM AUTHOR]

The purpose of this research is to establish a processing method for a wide-area nanometer scale periodic structure on the surface of a plastic plate in order to improve its hydrophobicity. We also evaluated the effect of a nanoperiodic structure applied in the uniaxial direction. Plastic plates of acrylonitrile–ethylene–styrene with dimensions of 100 × 100 mm2with a nanoperiodic structure on their surfaces were fabricated using a femtosecond laser and an injection molding technique. In the injection molding, the maximum transfer ratio for the depth reached as high as 0.79. When the nanoperiodic structure was applied in the uniaxial direction, the apparent contact angles did not decrease with respect to the direction of the ridges. As a result, the apparent contact angle increased by 20.4°, from 77.2° to 97.6° which is equivalent to 26%. In the six-month duration test, the sliding angle was initially decreased by applying the nanoperiodic structure. Additionally, the sliding angle was maintained between 20° and 38.3° during the duration test, which was lower than the angle for the flat plate at 42.7°. It can be considered that the depth was sufficient to maintain the sliding angle. In this condition, the contact angle hysteresis did not differ with or without the nanoperiodic structure on the surfaces, an effect that could be caused by surface dirt. In summary, the plastic plate was well drained and the characteristics were maintained for several months by forming the nanoperiodic structure on the surface. [ABSTRACT FROM AUTHOR]

In order to enable higher density recording, a better understanding of the magnetic disk/head interface is required. Therefore, the nanowear properties of extremely thin diamond-like carbon (DLC) films deposited on a Si(1 0 0) surface via filtered cathodic vacuum arc (FCVA) and electron cyclotron resonance-chemical vapor deposition (ECR-CVD) methods were evaluated using atomic force microscopy. It is proposed that tribochemical reactions led to the formation of protuberances on the thin DLC films coated on Si substrates. However, the FCVA-DLC films were more resistant to these tribochemical reactions of Si than the ECR-CVD-DLC films. For both 1.5-nm-thick ECR-CVD-DLC and 0.8-nm-thick FCVA-DLC films, the film was removed even at low loads, and the protuberances increased with the load because of direct contact between the diamond tip and the Si surface. Diamond tip sliding at higher loads also removed thicker ECR-CVD-DLC films, while thicker FCVA-DLC films remained on the Si surface and prevented tribochemical reactions. Furthermore, thicker ECR-CVD-DLC films exhibited deeper wear depths than FCVA-DLC films. These results reveal the differences in the resistance to wear and tribochemical reactions of extremely thin DLC films prepared using different deposition methods and confirm the superior properties of FCVA-DLC films. [ABSTRACT FROM AUTHOR]

In this paper we investigate the Total Ionizing Dose (TID) response of an UltraThin Buried-OXide (UTBOX) on a Fully Depleted Silicon-On-Insulator (FDSOI) high-k/metal gate technology. The impact of thinning the BOX and of the use of a Ground Plane (GP) at the back side of the BOX on the TID behavior are discussed by comparing their results to ionizing radiation experiments performed on reference FDSOI devices. [ABSTRACT FROM AUTHOR]

The effects of surface energy on the interaction between holes or edge are investigated. Three typical problems are discussed: (1) an infinite plate containing two holes of unequal size subjected to an all-round tension, (2) a circle disc containing an eccentric hole subjected to uniform pressure on either external or internal surface, (3) a semi-infinite plate containing an unstressed circular hole subjected to a uniform tension parallel to its straight edge. The problems are solved by series expansion in bipolar coordinates. The results show that the surface energy significantly affects the stress concentrations around the holes as the size of the holes shrinks to nanometers. Meanwhile, the interaction between the holes or edge influences the stress distribution around the holes or edge, which becomes evident as the holes or edge close to each other and is affected by the surface effect significantly. [ABSTRACT FROM AUTHOR]

Abstract: We review the use of scanning electron microscopy (SEM), atomic force microscopy (AFM) and force spectroscopy (FS) for probing the ultrastructure, chemistry, physical characteristics and motion of fungal cells. When first developed, SEM was used to image fixed/dehydrated/gold coated specimens, but here we describe more recent SEM developments as they apply to fungal cells. CryoSEM offers high resolution for frozen fungal samples, whereas environmental SEM allows the analysis of robust samples (e.g. spores) under ambient conditions. Dual beam SEM, the most recently developed, adds manipulation capabilities along with element detection. AFM has similar lateral and better depth resolution compared to SEM, and can image live cells including growing fungal hyphae. FS can analyze cell wall chemistry, elasticity and dynamic cell characteristics. The integration of AFM with optical microscopy will allow examination of individual molecules or cellular structures in the context of fungal cell architecture. SEM and AFM are complementary techniques that are clarifying our understanding of fungal biology. [Copyright &y& Elsevier]

Nanometerscale textured layers were achieved by annealing corresponding elemental layers, deposited in nanometerscale thickness which fits to the intended stoichiometry of the resulting compounds. The compound formation as well as the accompanying thermoelectric properties are reported. The compound formation corresponds in particular to the evolution of the Seebeck coefficient. [ABSTRACT FROM AUTHOR]

Major challenges in the field of electrochemical DNA hybridization biosensors are the immobilization of DNA and the detection of hybridization signals. The method of DNA immobilization using the nano-patterning machine and detection for DNA hybridization signals has been proposed. Here, two gold electrodes were deposited on SiO2 layer and the gap between the electrodes was fabricated by electron beam lithography. 3-aminopropyltriethoxysilane (APTES) solution was selectively treated to immobilize the amino-modified oligonucleotides onto the SiO2 layer between the electrodes. The recognition of DNA hybridization was accomplished by metallic aggregation of nano-particles. The results showed that DNA is immobilized with nanometer scales and the method for detecting hybridization signals is useful. The experimental results were verified by I-V curves. The conductance between two electrodes changed with the density of the Au-nanoparticles immobilized onto the oxide layer. These results can be applied to the DNA chip and the multi-functional sensors which will be researched in the further study. [ABSTRACT FROM AUTHOR]

Electrically conductive composite powders and compounds were produced using a mechanical alloying method. As starting materials, copper powder and a mixture of butadiene–acrylonitrile-copolymer and polyvinylchloride were used. After alloying, the powderlike material consisted of a mixture of fine copper powder embedded in the polymer matrix. Milling resulted in a copper powder of particle size 300 nm to 2 μm. The alloyed powders were compacted at a pressure of 0.37 GPa at 90°C with a holding time of 1 minute. The resistivity of the compound was measured to be 8.6 × 10 -4 ohm-cm. The unusual reduction in particle size to the nanometer level and formation of spherically formed copper polymer composite particles is explained by the reactions of the copper atoms with cyano and other functional groups of the polar polymers. The structurally modified polymer forms a tight encapsulation coating on the surface of the copper, and the flat-formed metal particles are recovered in spherical form due to strong interfacial forces, resulting in increased electrical conductivity. [ABSTRACT FROM AUTHOR]

One of the important aspects in the development of high-throughput platforms based on a fleet of scientific instruments in the form of miniature wireless robots designed for fast operations at the nanometer-scale, is the conception of an embedded locomotion system capable of fast displacements between two successive locations while being accurate enough to position the robot within the range of the embedded instrument, typically within a few tenths of nanometers. This paper describes not only the fundamental principles of the locomotion method and mechanisms but the main constraints, challenges, and environmental conditions that must be taken into account in the implementation of such a system, Preliminary experimental results show the validity of this approach. [ABSTRACT FROM AUTHOR]

Recently, nanotechnology has entered the fields of sensors and biosensors. Of particular interest is how sensitivity, selectivity, and switching may be improved by directly contacting single molecules. To achieve this goal, the fabrication of electrodes separated by nanometric size gaps that may be bridged by single molecules is necessary. Two approaches to fabricate nanometric sized contacts were recently proposed in literature. The first involves the movement of electrodes pairs. The second relates to the formation of electrodes pairs via etching. The aim of this work is to review techniques of fabricating nanometer scale gaps between conducting materials, used to form nanocontacts to single molecules. [Copyright &y& Elsevier]

Most structural materials existing in nature take the form of a composite. After centuries of evolution, these materials have gained highly optimized microstructures and performance. In this work, a natural biocomposite, chafer cuticle, was observed with SEM, and it was found that the insect cuticle has a laminated structure with chitin fiber and protein matrix. Special helicoidal layups of chitin fibers were found with the chitin fiber being of nanometer scale. The relationship between the nanometer scale of the chitin fiber and the fracture strength of the cuticle was analyzed. The results show that the nanometer scale of the chitin fiber is profitable to maintain and improve the fracture strength of the biocomposite. [ABSTRACT FROM AUTHOR]