Materials (Total 192907 Papers Found)

More than fifty years after the publication of the early work on conduction and dielectric breakdown of solids, we are still unable to describe quantitatively the electrical response of these materials. During this period of time, concepts derived from semiconductor physics have been transposed to the case of insulating solids, and among them, to polymers. Alternative descriptions have been proposed as well. In spite of this, there is still no agreement on how to describe charge transport and th ...
Carbon nanotubes (CNT) are of great commercial interest. Theoretically, during processing and handling of CNT and in abrasion processes on composites containing CNT, inhalable CNT particles might be set free. For hazard assessment, we performed a 90-day inhalation toxicity study with a multiwall CNT (MWCNT) material (Nanocyl NC 7000) according to Organisation for Economic Co-operation and Development test guideline 413. Wistar rats were head-nose exposed for 6 h/day, 5 days/week, 13 weeks, total ...
Fungal growth in damp or water-damaged buildings worldwide is an increasing problem, which has adverse effects on both the occupants and the buildings. Air sampling alone in moldy buildings does not reveal the full diversity of fungal species growing on building materials. One aim of this study was to estimate the qualitative and quantitative diversity of fungi growing on damp or water-damaged building materials. Another was to determine if associations exist between the most commonly found fung ...
The axial transmission technique uses a linear arrangement of ultrasonic emitters and receivers placed on a same side of a cortical bone site in contact with the skin, involving ultrasonic propagation along the axis of bone. The velocity of the waves radiated from bone has been shown to reflect bone status. The thickness and composition of soft tissue may vary along the length of the bone, between different skeletal sites, or between subjects. Hence, accurate estimates of velocity require first ...
If a high and on-going research dynamics is taken as a rejuvenating factor microfluidics can still be regarded as a truly young discipline, although some microfluidic devices definitely can not be considered as “youngsters” any more. In a time of 30 years of ISFETOLOGY it may be worth to take a look at these devices in order to examine, whether they had—and still have—the potential to stimulate the imagination and creativity of researchers in a similar way as the Ion Sensitive Fieldeffec ...
Existing wastewater treatment options are generally perceived as energy intensive and environmentally unfriendly. Much attention has been focused on two new approaches in the past years, (i) microbial fuel cells and (ii) microbial electrolysis cells, which directly generate electrical current or chemical products, respectively, during wastewater treatment. These systems are commonly denominated as bioelectrochemical systems, and a multitude of claims have been made in the past regarding the envi ...
THE development of the gradient force optical particle trap ('optical tweezers') has made it possible to manipulate biological materials using a single beam of laser light1. Optical traps can produce forces in the microdyne range on intact cells without causing overt damage: such forces are sufficient to arrest actively swimming bacteria2 and can overcome torque generated by the flagellar motor of a bacterium tethered to a glass surface by a flagellar filament. By calibrating the trapping force ...
Nanoparticles that self-assemble on a liquid-liquid interface serve as the building block for making heterodimeric nanostructures. Specifically, hollow iron oxide nanoparticles within hexane form colloidosomes in the aqueous solution of silver nitrate, and iron oxide exposed to the aqueous phase catalyzes the reduction of silver ions to afford a heterodimer of silver and hollow iron oxide nanoparticles. Transmission electron microscopy, selected area electron diffraction, energy-dispersive X-ray ...
In this study, rice straw-wood particle composite boards were manufactured as insulation boards using the method used in the wood-based panel industry. The raw material, rice straw, was chosen because of its availability. The manufacturing parameters were: a specific gravity of 0.4, 0.6, and 0.8, and a rice straw content (10/90, 20/80, and 30/70 weight of rice straw/wood particle) of 10, 20, and 30 wt.%. A commercial urea-formaldehyde adhesive was used as the composite binder, to achieve 140-290 ...
To support pharmacokinetic and drug metabolism studies, LC-MS/MS plays more and more an essential role for the quantitation of drugs and their metabolites in biological matrices. With the new challenges encountered in drug discovery and drug development, new strategies are put in place to achieve high-throughput analysis, using serial and parallel approaches. To speed-up method development and validation, generic approaches with the direct injection of biological fluids is highly desirable. Colu ...
In areas where respirators are not routinely used, emergencies (such as fires) may occur in which protection from airborne particles is necessary. The following readily available materials were tested on a manikin connected to a breathing simulator to determine the fraction of an approximately 2-micron diameter aerosol that would leak around the seal between the materials and the manikin's face: cotton/polyester shirt material, cotton handkerchief material, toweling (a wash cloth), a surgical ma ...
We present the dispersion relations for symmetric planar waveguides in general isotropic media. The planar waveguide structure that utilizes chiral media in the cladding regions is emphasized. Unlike other symmetric planar waveguide configurations in isotropic media, this structure possesses a nondegenerate lowest-order mode. Therefore symmetric planar waveguides using chiral cladding materials can support single-mode operation. ...
Assessment of yield performance under fluctuating environmental conditions is a major aim of crop breeders. Unfortunately, results from controlled-environment evaluations of complex agronomic traits rarely translate to field performance. A major cause is that crops grown over their complete lifecycle in a greenhouse or growth chamber are generally constricted in their root growth, which influences their response to important abiotic constraints like water or nutrient availability. To overcome th ...
The cell recognition of bioactive ligands immobilized on polymeric surfaces is strongly dependent on ligand presentation at the cell/material interface. While small peptide sequences such as Arg-Gly-Asp (RGD) are being widely used to obtain biomimetic interfaces, surface characteristics after immobilization as well as presentation of such ligands to cell receptors deserve more detailed investigation. Here, we immobilized an RGD-based sequence on poly(epsilon-caprolactone) (PCL), a largely widesp ...
Within this paper we present the fabrication of nano crosspoint junctions and arrays with electron beam direct writing (EBDW). Reactively sputtered TiO<inf>2</inf> was incorporated as a resistively switching thin film and electrically characterized concerning its performance. These devices are suitable for novel non-volatile storage systems in form of resistive random access memories (RRAM). All used materials as well as the fabrication processes for the functional thin film are in g ...
Well-aligned Cu(OH)2 nanoribbon and CuO nanorod arrays have been prepared on copper substrates by liquid-solid reactions. The effects of temperature, reaction time, solvent, and pH value on the morphology and composition of the products are systematically studied. Using the Cu(OH)2 nanoribbons array as a reactive and sacrificial template, we have successfully synthesized Cu2O, Cu9S8, and Cu nanoribbon/ nanowire arrays, demonstrating the versatility of the template. The extensive series of copper ...
Temperature is a key parameter in physiological processes, and probes able to detect small changes in local temperature are necessary for accurate and quantitative physical descriptions of cellular events. Several have recently emerged that offer excellent temperature sensitivity, spatial resolution, or cellular compatibility, but it has been challenging to realize all of these properties in a single construct. Here, we introduce a luminescent nanocrystal-based sensor that achieves this with a 2 ...
Nanoparticles have increasingly been used for a variety of applications, most notably for the delivery of therapeutic and diagnostic agents. A large number of nanoparticle drug delivery systems have been developed for cancer treatment and various materials have been explored as drug delivery agents to improve the therapeutic efficacy and safety of anticancer drugs. Natural biomolecules such as proteins are an attractive alternative to synthetic polymers which are commonly used in drug formulatio ...
Students in psychology need to learn to design and analyze their own experiments. However, software that allows students to build experiments on their own has been limited in a variety of ways. The shipping of the first full release of the E-Prime system later this year will open up a new opportunity for addressing this problem. Because E-Prime promises to become the standard for building experiments in psychology, it is now possible to construct a Web-based resource that uses E-Prime as the del ...
Liquid crystal ‘blue phases’ are highly fluid self-assembled three-dimensional cubic defect structures that exist over narrow temperature ranges in highly chiral liquid crystals. The characteristic period of these defects is of the order of the wavelength of visible light, and they give rise to vivid specular reflections that are controllable with external fields. Blue phases may be considered as examples of tuneable photonic crystals with many potential applications. The disadvantage of the ...
We use conventional and multispeckle dynamic light scattering to investigate the dynamics of a wide variety of jammed soft materials, including colloidal gels, concentrated emulsions, and concentrated surfactant phases. For all systems, the dynamic structure factor f(q,t) exhibits a two-step decay. The initial decay is due to the thermally activated diffusive motion of the scatterers, as indicated by the q(-2) dependence of the characteristic relaxation time, where q is the scattering vector. Ho ...
Bending of worm-like polymers carries an energy penalty which results in the appearance of a persistence length lp such that the polymer is straight on length scales smaller than lp and bends only on length scales larger than this length. Intuitively, this leads us to expect that the most probable value of the local curvature of a worm-like polymer undergoing thermal fluctuations in a solvent, is zero. We use simple geometric arguments and Monte Carlo simulations to show that while this expectat ...
The objective of this study is to develop and investigate a reliable electrical interconnection for SiC-MEMS, which can sustain high mechanical and thermal loads in harsh environments. Platinum and palladium wire bonds, with a diameter of 25 microns, are used for interconnection of sensors with an operating temperature of 500 °C. Silicon testsensors with TiW/Pt bond pad metallization are processed in thin film technology. The test-chips are mounted with temperature stable assembly techniq ...
The presence and concentration of oxygen in biological systems has a large impact on the behavior and viability of many types of cells, including the differentiation of stem cells or the growth of tumor cells. As a result, the integration of oxygen sensors within cell culture environments presents a powerful tool for quantifying the effects of oxygen concentrations on cell behavior, cell viability, and drug effectiveness. Because microfluidic cell culture environments are a promising alternative ...
Single layers of WS2 nanoplates are uniformly embedded in nitrogen-doped carbon nanofibers (WS2@NCNFs) via a facile electrospinning method. Crystallization of the single-layered WS2 nanoplates and in situ nitrogen doping into the carbon nanofibers were simultaneously accomplished during a two-step heat treatment. The distinctive structure of the WS2@NCNFs enables outstanding electrochemical performances. ...
Responsive assembly of 2D materials is of great interest for a range of applications. In this work, interfacial functionalized carbon nitride (CN) nanofibers were synthesized by hydrolyzing bulk CN in sodium hydroxide solution. The reversible assemble and disassemble behavior of the as-prepared CN nanofibers was investigated by using CO2 as a trigger to form a hydrogel network at first. Compared to the most widespread absorbent materials such as active carbon, graphene and previously reported su ...
A biological indicator (BI) measures the effectiveness of the sterilization process to which it is subjected. Factors such as the test organism, the packaging, the culture material, and the test system all influence a BI's resistance. Carrier material is an often-overlooked factor that also influences BI resistance. The authors examine various solid and liquid carriers, describe their properties, and investigate how they influence BI resistance. A biological indicator (BI) is an "inoculated carr ...
The structure and the toughening mechanism of nacre have been the subject of intensive research over the last 30 years. This interest originates from nacre's excellent combination of strength, stiffness and toughness, despite its high, for a biological material, volume fraction of inorganic phase, typically 95%. Owing to the improvement of nanoscale measurement and observation techniques, significant progress has been made during the last decade in understanding the mechanical properties of nacr ...
The aim of this document is to define an integrated model for adaptive learning, based on existing specifications. Such a model should help to achieve a common understanding of relevant concepts in personalized adaptive e-learning and to clarify their relationships with current learning technology standards. Keyword list: adaptive learning, personalization, learning standards Disclaimer: All information included in this document is subject to change without notice. The Members of the GRAPPLE Con ...
A flexible transparent film uwb antenna for curved surfaces has been designed and developed for wireless communications. The antenna has demonstrated good performance over the entire UWB bandwidth. It can be mounted on any conformal shape by virtue of the film properties of both the antenna as well as the substrate. The radiator and ground are both designed using AgHT-8 while the substrate is of a polymer. The antenna is shown to be able to maintain its performance below the 10dB level throughou ...
Deuterated arylamines demonstrate great potential for use in optoelectronic devices, but their widespread utility requires a method for large-scale synthesis. The incorporation of these deuterated materials into optoelectronic devices also provides the opportunity for studies of the functioning device using neutron reflectometry based on the difference in the scattering length density between protonated and deuterated compounds. Here we report mild deuteration conditions utilising standard labor ...
Development of the composites with natural fibers and fillers as a sustainable alternative material for some engineering applications, particularly in aerospace applications and automobile applications. Natural fiber composites are more attractive due to their highest specific strength, light weight and biodegradability and low cost. In this paper the hybrid composite are in the form of jute/glass fiber, sisal/glass fiber, natural rubber/glass fiber, natural rubber/jute fiber. The properties of ...
We report a catalytic asymmetric total synthesis of the ascidian natural product perophoramidine. The synthesis employs a molybdenum-catalyzed asymmetric allylic alkylation of an oxindole nucleophile and a monosubstituted allylic electrophile as a key asymmetric step. The enantioenriched oxindole product from this transformation contains vicinal quaternary and tertiary stereocenters, and is obtained in high yield along with high levels of regio-, diastereo-, and enantioselectivity. To install th ...
The sensing properties of carbon nanomaterials are studied and compared in this paper. Graphene oxide and multi-walled carbon nanotube films were used as active layers of chemoresistive gas sensors and characterized at room temperature towards ammonia detection in concentration levels from 100 ppm to 500 ppm in air. We conclude that graphene oxide based sensor has higher response (2.4% to 7.4% in range from 100 ppm to 500 ppm) than the multi-walled carbon nanotubes based one (1.0-2.4%). On the o ...
Two mesoporous ordered carbon materials (MOCs) have been synthesized from silica templates by using sucrose as the carbon precursor. The textural characterization using Ar, N2, and CO2 adsorption combined with neutron diffraction showed that the two samples exhibit a significant microporous volume close to 0.5 cm3/g and an ordered network of mesopores. For both MCM48 and SBA15 templated carbons, adsorption first proceeds with the filling of micropores and then by the filling of mesopores with an ...
Single walled carbon nanotubes (SWNTs) continue to demonstrate the potential of nanoscaled materials in a wide range of applications. The ability to modulate the mechanical or electrical properties of a material by varying the SWNT component may result in diverse "application tunable" materials. Similarly, biomaterials used in tissue engineering applications may benefit from these characteristics by varying electrical and mechanical properties to enhance or direct tissue specific regeneration. T ...
Site-selective bioconjugation methods are valuable because of their ability to confer new properties to proteins by the chemical attachment of specific functional groups. Well-defined bioconjugates obtained through these methods have found utility for the study of protein function and the creation of protein-based materials. We have previously reported a protein modification strategy to modify the N-terminus of peptides and proteins using N-methylpyridinium-4-carboxaldehyde benzenesulfonate (Rap ...
The investigation into the filterability of raw sugar was In response to occasional complaints from customers, attention has focused on the filtration behaviour of raw sugars. Offending sugars, together with several others, were extensively analysed to establish the probable causes of the problem. Parameters correlating most strongly with poor filterability were turbidity and soluble phosphate (r = -0,83; n = 32) and (r = -0,76; n = 32) respectively. Starch (r = -0,67; n = 32), suspended solids ...
This study describes our efforts to study some of the mechanistic aspects of the earlier established on-surface enzymatic digestion (oSED) method. In a multitude of application areas, it has become important to be able to fully characterize and understand selective protein adsorption to biomaterial surfaces for various applications, including biomedicine (implants), nanotechnology (microchip surfaces and sensors) and materials sciences. Herein, the investigation of the mechanistic aspects was ba ...
Selective catalysts that activate small molecules such as hydrocarbons, dioxygen, water, carbon dioxide and dihydrogen are central to new technologies for the use of alternative energy sources. For example, controlled hydrocarbon functionalization can lead to high impact technologies, but such catalysts require a level of molecular control beyond current means. The Center for Catalytic Hydrocarbon Functionalization facilitates collaborations among research groups in catalysis, materials, electro ...
In this work, hybrid bonding platform is successfully developed with solder bonding and photosensitive polyimide (PI) at 250 °C. Since solder may be affected by the curing process of polymer owing to its low melting point, an asymmetry hybrid bonding structure is proposed to overcome this issue. Metal and polymer can be well bonded simultaneously with wide integration flexibility through various ratios of polymer to metal. The mechanical strength of bonded structure is substantially impro ...
(2010). Students' appraisal of emotional and relational experience whilst collaborating online using text based communication. Copyright and Moral Rights for the articles on this site are retained by the individual authors and/or other copyright owners. For more information on Open Research Online's data policy on reuse of materials please consult the policies page. Abstract The impacts that the lack of physical cues and non-verbal cues of emotional expression has on the student learning experie ...
In this study, novel thermoplastic APL structure has been newly introduced into the conventional ACFs system. The APL structure can effectively suppress the movement of conductive particles during the ACFs bonding process resulting in significant improvement of conductive particle capture rate on a bump and solving electrical short problems at ultra-fine pitch assemblies such as COG(Chip On Glass) and COF(Chip On Flex) applications. The selection of thermoplastic material of APL structure determ ...
An environmentallly friendly, homogeneous catalytic method for the oxidation of alcohols in aqueous medium is described. The copper(II) complex, [Cu(4-CNpy)2Cl2]n, has been prepared in excellent yield and characterized by the single crystal X-ray diffraction technique. It crystallizes in the monoclinic space group P21/n with unit cell parameters a = 3.589(3)Å, b = 25.903(6) Å, c = 7.116(1)Å, β = 96.05(4)°, V = 657.9(6) Å, and Z = 2. The crystal structure refinement yields final R1 = 0.0604 ...
The effects of hydrophobic polymer content and loading in the gas diffusion and microporous layers on the performance of an H2/O2 proton exchange membrane fuel cell were investigated. A membrane-electrode assembly with a microporous layer containing 20 wt.% polytetrafluoroethylene exhibits the best performance. Furthermore, a microporous layer loading of 1.5 milligrams of polytetrafluoroethylene and carbon powder per square centimeter of the gas diffusion electrode shows the best result. Electro ...