PDF superior Application of conducting polymers in nanobiotechnology

Application of conducting polymers in nanobiotechnology

Application of conducting polymers in nanobiotechnology

Complexes formed by 6-mer of single-stranded homo-nucleotides and poly(3,4- ethylenedioxythiophene), a π -conjugated polymer, have been investigated from both experimental and theoretical points of view. UV-Vis absorption and circular dichroism spectra indicate that adenine and cytosine homo-nucleotides form stable and compact adducts with the conducting polymer, which are stabilized by non-specific electrostatic interactions. In contrast, complexes involving the guanine homonucleotide are clearly dominated by specific hydrogen bonds. A hierarchical modeling approach has been used to gain some information of the complex formed by the homo-nucleotide of guanine and the polymer at both the molecular and electronic levels. Atomistic molecular dynamics simulations reveal that upon complexation the B-DNA conformation of the homo- nucleotide unfolds into a completely disordered arrangement, which allows the simultaneous formation of N-H∙∙∙O and N-H∙∙∙S hydrogen bonds, N-H∙∙∙ π , π - π stacking and electrostatic interactions with the extended polymer molecule. In spite of such variety of interactions, specific hydrogen bonds have been found to be the most abundant and decisive in this complex. The study has been complemented by ab initio and density functional theory calculations to examine the specific interactions between 1- methylguanine and 3,4-ethylene-dioxythiophene (G:EDOT). The energy decomposition analyses performed show that the stability of the different structures is governed by the attractive electrostatic interaction and reveal the reason why the N–H∙∙∙O hydrogen bond is the strongest specific interaction between these two molecules. *
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313 Lee mas

Sensory polymeric foams as a tool for improving sensing performance of sensory polymers

Sensory polymeric foams as a tool for improving sensing performance of sensory polymers

pH 2.2 buffered: KCl/HCl). These conditions were selected for two main reasons: First, the Hg(II) detection must be carried out in acid media, due to the interference problems observed when using a basic media for the Hg(II) sensing. Secondly, we employed a high Hg(II) concentration in order to reduce the detection time and capture in video the whole process. It is possible to use lower concentrations (in the range of 5 ppm) which are close to the concentration of a real application, but in this case, the detection time would increase up to several hours. Two square samples of 20 × 20 mm 2 were immersed in the solution, one corresponding to the foamed region and the other one extracted from the solid region of the film. Additionally, a plastic piece was placed between both samples and was used as a blank reference in the RGB (R = red, G = green, B = blue) calculations. The whole sensing process was captured in video for 60 min, then extracting different photographs of the color evolution of the discs at different times to perform the RGB analysis. A total number of 26 photographs were extracted from the video, following the next distribution: During the first 20 min, one photograph each minute was taken. Then, from 20 min to 30 min, one photograph each 5 min, and finally, from 30 min to 60 min, one photograph each 10 min.
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9 Lee mas

Are the Accompanying Cations of Doping Anions Influential in Conducting Organic Polymers? The Case of the Popular PEDOT

Are the Accompanying Cations of Doping Anions Influential in Conducting Organic Polymers? The Case of the Popular PEDOT

anions, cations are removed from the matrix and during the reduction process cations are taken in. This is the usual reference to cations when dealing with COPs. As said these COPs can be oxidized and reduced. They fall within the definition of redox polymers, to say polymers that alter their properties after gaining or losing electrons in a reversible way. 1 All the above mentioned polymers can have pendant arms, as is common with conventional organic polymers. The reversible redox reaction may occur in the polymer main-chain, as in the case of conducting organic polymers (COP) or in side-groups, mostly made of ferrocene, 1-8 and few examples with cobaltocene, 9-11 cobaltobisdicarbollide 12-16 and cobaltopolypyridyl 17, 18 units. The redox process can become more complex but may provide more challenging properties if the redox centers are both in the conjugated backbone and in the side branches. 1 Polymers with optical,
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27 Lee mas

Breakup of a supported drop of a  viscous, conducting liquid in a uniform field

Breakup of a supported drop of a viscous, conducting liquid in a uniform field

The elongation of a drop attached to a metallic plate fol- lowing the application of a uniform electric field has been described numerically for liquids of finite electrical conduc- tivity in the absence of inertial effects. The elongation of the drop leads to a hydrostatic equilibrium if the applied field is smaller than a certain critical value, or to the emission of daughter droplets at higher fields. In the latter case, and in the ranges of parameters that have been investigated, the computation reproduces an evolution often observed in ex- periments. The drop develops a conical shape around its tip and ejects a fine jet that emits small charged droplets. The flow rate and the electric current carried by the stream of droplets are determined by the flow and the transport of elec- tric charge in the attached drop and in a leading region of the jet, where the solution is nearly time independent and ame- nable to a simplified analysis. The effect of the finite conduc- tivity of the liquid comes into play in a region at the begin- ning of the jet where the solution departs from that for a liquid of infinite conductivity. In this region, the electric field normal to the surface reaches a maximum, the rate of varia- tion of the radius of the jet with streamwise distance de- creases substantially, and convection of the surface charge becomes the mechanism responsible for most of the electric current. The electric stresses dominate surface tension stresses in this region and in the attached drop when the applied field is moderately larger than its critical value and the electrical conductivity is high. The balance of electric and viscous stresses gives then a flow rate that increases as the square of the applied field, while the order of the electric current can be determined from a qualitative analysis of the current transfer region of the jet.
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11 Lee mas

Ph Sensitivity Polymers For Potential Biomedical Application Obtained By Gamma-Ray

Ph Sensitivity Polymers For Potential Biomedical Application Obtained By Gamma-Ray

The present work was made in the Institute of Nuclear Sciences at UNAM, which consist of the synthesis of hydrogels based on a compound of agar and acrylic acid, cross-linked by gamma rays. The study of different parameters such as doses, monomer concentrations, the temperature during the mixture, and reaction time to determine the optimal conditions during the synthesis. The obtained samples were characterized by different techniques. To determine the functional groups was used FTIR-ATR spectroscopy. Thermal techniques were performed by DSC to determine the glass transition (Tg), while, TGA analyzes the decomposition of the mass against the temperature. Also, characterization physico-chemical as maximum swelling, cyclic changes of pH, contact angle and mechanical tests were performed. Additionally, silver nanoparticles (AgNPs) were synthesized to provide an antimicrobial activity to the hydrogel. The load and delivery of AgNPs and and ciprofloxacin employed UV -VIS spectroscopy to determine its wavelength and absorbance according to the Lambert Beer-Law. The final material incorporated with antimicrobial agents was subjected to microbiological tests.
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83 Lee mas

Why is the Sensory Response of Organic Probes within a Polymer Film Different in Solution and in the Solid State? Evidence and Application to the Detection of Amino Acids in Human Chronic Wounds

Why is the Sensory Response of Organic Probes within a Polymer Film Different in Solution and in the Solid State? Evidence and Application to the Detection of Amino Acids in Human Chronic Wounds

As has been previously mentioned, chemicals in the solid‐state exhibit different properties than  in solution, and this fact can be exploited for other purposes. Thus, chemicals dispersed in a polymer  matrix,  or chemically anchored to a polymer backbone, in the  amorphous state,  and  isolated one from  another  by  polymers  chains,  or  sections,  with  high  restriction  in  movement,  exhibit  different  properties  because  their  chemical  environment  is  different.  For  instance,  highly  thermally  labile  chemical groups, that cannot be isolated in conventional organic chemistry, such as diazonium salts,  can  be used  without care at room temperature,  for weeks, and exploited  as  sensors  in  sensing  harmful  chemicals in water media, when anchored to polymer backbones [2]. It is as if the polymer chains  generate a protective environment for the labile group, and generalising, the polymer chains deeply  influence the interactions that the chemicals within the polymer matrix can establish with others.   
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19 Lee mas

An Electrochemical Desalination Cell Based on Conducting Polymers

An Electrochemical Desalination Cell Based on Conducting Polymers

CDI is a technology that removes ions from water as opposed to RO, which removes water from salty solutions. In a CDI electrochemical cell, saltwater flows between a cathode and an anode held at a potential difference sufficiently high to attract and adsorb cations and anions, respectively. The electrodes are typically carbon based. Once the two electrodes are saturated with ions, the polarity of the cell is reversed to release the adsorbed ions into a drain stream. In more recent developments, the CDI electrodes are coated with deionization membranes to overcome efficiency issues and sluggish kinetics. In this regard, conducting polymers, such as polypyrrole (PPy) and polyaniline (PANI), have been used as membranes for individual electrodes in CDI (7-9) .
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11 Lee mas

Formulation of anticorrosive paints employing conducting polymers

Formulation of anticorrosive paints employing conducting polymers

PAni-EB has been extensively employed as anticorrosive additive due to its very high stability and good redox properties, which are able to passivate the metal surface through an anodic protection mechanism. However, this CP is extremely insoluble, forming agglomerates when it is in contact with solvents. The key for the good miscibility with our paint formulation was achieved by reducing the PAni powder size, which was subsequently mixed with chloroform to form a very fine colloidal dispersions, as suggested by B. Wessling in reference [25]. Another important requirement for the use of PAni-EB in paint formulations is the addition of a very low concentration. We found that 0.3 wt.% is better than 1.0 or 1.5 wt.%. Thus, concentrations higher than 0.3 wt.% provoke the formation of polymer agglomerates in the film surface giving worse adherence and high permeability to the coating (this observation is detailed in section 6.3.2). In contrast, PAni-ES has excellent miscibility with solvent-based alkyd paints due to its good dispersion properties in xylene solutions. We did not observe the formation of agglomerates in the coating surface when PAni-ES 1.0 wt.% was employed. However, the best miscibility was obtained when we applied the partially oxidized PTE as additive. The PTh derivative synthesized in our laboratory showed a very high compatibility with the alkyd paint formulation, giving very smooth coating surfaces for concentrations ranging between 0.3 to 1.5 wt.%. This high compatibility should be attributed to the fact that PTE is soluble in the paint solvents (i.e. alcoholic solvents and aromatic hydrocarbons).
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197 Lee mas

Lattice defects and boundaries in conducting carbon nanotubes

Lattice defects and boundaries in conducting carbon nanotubes

The tight-binding band structure of an infinite graphene sheet includes a valence band and a conduction band that touch at two distinct Fermi points. When this graphite mono- layer is rolled into a CNT, boundary conditions are imposed such that only a finite set of bands are allowed. As mentioned above, in some cases a subset of bands coincides with the Fermi points and the tube is metallic. The present section is devoted to show how to obtain an effective low-energy theory for conducting SWCNTs by keeping only its conduc- tion bands. The result is a dramatically simplified description of the tubes in terms of two chain models. To be able to take advantage of these simple lattice models, we do not need to recur to the widely used linearization around the Fermi points. 4,31,38,39 The procedure will be outlined for the arm- chair and conducting zigzag nanotubes for which the con- duction bands can be easily identified and isolated once a Fourier transform around the tube is performed.
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14 Lee mas

Application of virtual reality in a learning experience

Application of virtual reality in a learning experience

The implementation of the application using Internet solve this problem, being able to have classes even at homes, students attend the simulation with the ”virtual” presence of the teacher, and if they have questions outside class time, could access it to better investigate, without having to wait for use. With the creation of these simulation and studies centers, teaching of abstract matters would be benefit, since the manipulation of parameters, changes involving them and their importance in the studied model could be perceived in a better way. Both students and teachers have at their disposal a powerful tool in education, particularly in vocational subjects in technical field.
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10 Lee mas

Application of virtual reality in a learning experience

Application of virtual reality in a learning experience

The project is an application that allows users to interact in a virtual environment via a web interface, in which models are in three dimensions to simulate different activities. The application focuses on education with virtual reality technology, enriching the student's perception through the interaction with objects in an artificial world, facilitating their learning. A website was designed for this purpose, on which the application can be executed directly in the web browser with the help of a plugin or downloaded and run as a native application. The user navigates in the virtual environment containing a three-dimensional replica of one of the laboratories of the Polytechnic School UNE. The tests consisted of running the model and laboratory simulations. The results obtained from forms show that the use of virtual reality is valid, accepted and helps understanding the context of the simulations. Keywords: Virtual Reality, Simulation, Computer Graphics, Education, Learning.
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5 Lee mas

Conducting action research projects in a teacher preparation program

Conducting action research projects in a teacher preparation program

In the analysis of the Action Research cycles in this study, curriculum reinforcement arose as one of the most significant aspects school administrators and head teachers highlighted in the teacher trainees’ performance; they repeatedly referred to the student teachers’ interest to comply with curriculum guidelines both at the school and the Ministry of Education levels; according to most of the administrators interviewed in the study, beginning teachers made big e orts to design research proposals to respond to the schools’ needs and curriculum requirements, making so valuable contributions to the achievement of curriculum standards. According to the documental analysis of research reports, it was stated that 85% of the proposals adapted lesson plans and materials to the schools’ emphases; as a ma ! er of fact, the schools’ Educational Institutional Projects determined the chosen teaching strategies, language contents, themes, and evaluation criteria in most of lesson plans or workshops. Teacher sta also interviewed throughout the data collection process, referred to research projects as updating sources in the Þ elds of methodology, materials design, and class management. Teacher trainees were referred to as innovation agents that promoted a fresher learning atmosphere into the foreign language classroom.
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22 Lee mas

Responsibility of the University in the University Company State Triad

Responsibility of the University in the University Company State Triad

This responsibility, as Rangel (2002) states, is inherent to fomenting the creation, development, dissemination, and innovation of knowledge and tech- nology. Companies are therefore urged to investigate the use and development of environmentally-friendly technologies that also allow improved efficiency and productivity. In this sense the global pact of the company is to combine wealth creation and environmental protection, a goal also set by the university, which acts a meeting point for different sectors and offers the possibility to create and promote strategic support partnerships for large-scale projects with major consequences and impacts. The author asserts that there is no single route for csr . It involves a long
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20 Lee mas

ANILINIUM SALTS AS SURFMERS IN THE SYNTHESIS OF ELECTRICALLY CONDUCTING POLYANILINE BASED COMPOSITES

ANILINIUM SALTS AS SURFMERS IN THE SYNTHESIS OF ELECTRICALLY CONDUCTING POLYANILINE BASED COMPOSITES

Styrene emulsion polymerization, was performed as follows: First, aqueous solution of DS-AN was loaded into the reactor and let to stabilize for 20 min at 70 °C in the presence of nitrogen. Afterwards, initiator V-50 was loaded to the reactor and the solution was let for 5 min more. Next, the emulsion was prepared by injecting the styrene monomer into the reactor with vigorous stirring. The relationship monomer to water was 20 to 80 (wt/wt). All polymerizations were performed at 70 °C, stirring of 300 rpm and let for 180 min with permanent flux of nitrogen. Once polymerizations finished the latexes were let cool and kept into covered vessels. Series of samples were taken along the polymerization to determine kinetics.
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5 Lee mas

New aromatic polyamides and polyimides having an adamantine bulky group

New aromatic polyamides and polyimides having an adamantine bulky group

Among the wide variety of polymers employed for advanced applications, aromatic polyimides (PIs) and aromatic polyamides (PAs) are considered as polymers with high technological interest due to their good mechanical properties, excellent thermal stability, elevated chemical resistance and high glass transition temperature[1– 4]. Furthermore, it is feasible to access to a wide variety of polyimide or polyamide structures by synthesis of new monomers or by simple modification of the polymer. By applying these modifications, polymers with tailor-made properties can be employed in high performance applications. Following this approach, it is affordable to design polymers having high fractional free volume (FFV) that show excellent properties to selectively separate mixtures of gases[5–7].This approach has been exhaustively employed for PIs even though the use of well-designed aromatic polyamides should be favored because the synthesis of PAs is less cumbersome and also their fabrication and processing cost are by far much lower than those of PIs materials[8,9]. Thus, and regarding their gas permeation properties, aromatic PAs and PIs have been improved by modification of their chemical structure, for example, introducing bulky side substituents that hinder the molecular packing[10–13]. Also, it is possible to increase, by playing with the molecular structure, the rigidity of the macromolecular backbone, which translates to an improvement of gas selectivity for a mixture of gases[14]. This combination of a loose structure and high rigidity produces materials having high permeability and good permselectivity[15,16].
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26 Lee mas

Application of the Just About Right Scales in the Development of New Healthy Whole Wheat Muffins by the Addition of a Product Obtained from White and Red Grape Pomace

Application of the Just About Right Scales in the Development of New Healthy Whole Wheat Muffins by the Addition of a Product Obtained from White and Red Grape Pomace

Consumers indicated the degree of liking of each muffin using a nine-point hedonic scale, ranged from 1 = “dislike extremely” to 9 = “like extremely” with middle value 5 = “neither like nor dislike”, whereas the adequacy of the six attributes (“surface colour”, “crumb colour”, “sweetness”, “hardness”, “sponginess” and “flavour”) was measured using “just-about-right” (JAR) bipolar scales of five points ranged (from 1 = “much less” to 5 = “much more” with middle value 3 = “just about right”). These scales are used in studies with consumers to establish whether a particular attribute is perceived in a product at an excessive, scarce or acceptable level. The extreme ends of the scale represent the level of an attribute that moves away from the ideal theoretical point in opposite directions, while the central point is the ideal or acceptable one [9]. Penalty analysis (PA) was carried out transforming the initial scale of five points into one of three points. For that, the responses “much less” and “less” were grouped into an unique group named “much less” and the responses “more” and “much more” were grouped in an unique group named “much more” [1,9,23,24].
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15 Lee mas

Use of new silica fillers as additives for polymers used in packaging of fruit

Use of new silica fillers as additives for polymers used in packaging of fruit

with higher amount of APS, at a constant HMDS content, is clearly observed. It can be assumed that the modifier is not only on the silica surface, but also forms part of its crystalline network. The floc- cules are likely produced by the excess of the modifier interacting with silanol and siloxane groups in the gel network. This different morphology could be associated to the APS compound, which can produce higher interaction through its amine group. The deformation confers a gummy texture to the solid, seen partially in the S7 sample and completely visible in the S8 sample, which is an elastic gum and could not be observed by TEM. The TEM micrograph of the S7 sample shows that the oval shape of the particles is lost, and instead a laminar shape is observed.
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5 Lee mas

Diaspora: concept, context, and its application in the study of new literatures

Diaspora: concept, context, and its application in the study of new literatures

NATURE AND FORMAT OF THE ARTICLES: The Revista would welcome ar ticles of the following kinds: (1) Articles on linguistics and ELT, literature, literary theory and criticism, history and other aspects of the culture of the English-speaking nations. Articles should not exceed nine thous and words in length. (2) Bibliogra phies of studies on very specifi c topics, providing a brief in troduction and a list of basic publications. A concise index of contents may optionally be included. (3) Reviews and review ar ticles on recently published books in the fi eld of English Stu dies. (4) Poetry translations (English-Spanish and Spanish-Eng lish). All articles submitted should follow the guidelines which can be obtained from the following Internet address:
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30 Lee mas

Application of game theory in inventory management

Application of game theory in inventory management

This work presents briefly some basic concepts of game theory and shows its applica- tion in inventory management by using modifications of the classic news vendor model. In the traditional news vendor model, the inventory problem is modeled as a single decision maker problem (for example, a retailer that wants to define an optimal order quantity for a particular product) where the decisions are made without consid- ering other competitors (for example, other retailers o firms that provide the same o similar product in the marketplace), and if there are different types of products, they cannot be substituted for each other. The problem with these assumptions is that in many real situations this is not true. Now, the question that arises here is: can we con- struct an inventory model that is able to describe such situations? The answer is YES. In particular, we can use Game Theory.
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12 Lee mas

Impact of water in the degradability and hemocompatibility of polymers for medical applications

Impact of water in the degradability and hemocompatibility of polymers for medical applications

Hemocompatibility tests showed that with higher amounts of NVP the number of platelets adhered to the surface was less than with samples with lower amounts of NVP, and these platelets conserved much of their original shape, indicating an inactivated state. The high content of NVP also increased the PRT, which indicates that coagulation around the polymer occurs slower than in copolymers with low NVP (L. S. Wan et al., 2005) (Figure 3-20). Relating this information with the water states data, the study suggests that the improved hemocompatibility is due to the higher amount of non-freezable water present in the polymer-water system. But in the calculation of non-freezable and freezable water the authors did not differentiate the latter between intermediate and free water. They did however identify the three different states of water in the polymer-water system through the IR analysis. Both non-freezable and intermediate water can be responsible for the improved hemocompatibility of the polymer and determining the amount of intermediate water with DSC or NMR will provide more information on its role on hemocompatibility.
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126 Lee mas

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