Search results for " solution"

Studies of network structure and dynamics of e-beam crosslinked PVPs: From macro to nano

2011

Much interest has been paid to develop a variety of radiation-crosslinked hydrated polymeric materials, which swell in water but do not dissolve, as biocompatible materials used for wound healing, drug delivery system, surface-coating material for medically used devices, etc. With the aim of establishing design rules to produce hydrogels of controlled size at the nanoscale and desired internal network structure using conventional electron accelerators and set-ups, here we attempt a description in terms of structural and dynamic properties of polymer networks generated through e-beam irradiation of aqueous solutions of the same model polymer, a commercial grade poly(N-vinyl-pyrrolidone), sub…

Préface Special Issue 'The Future of Agricultural Landscapes' part 1

2020

Préface de Advances in Ecological Research, Volume 63, the latest release in this ongoing series includes specific chapters on Tropical Ecosystems in the 21st Century. Chapters in this volume cover topics such as Landscape-scale expansion of agroecology to enhance natural pest control: a systematic review and Ecosystem services and the resilience of agricultural landscapes

Quantitation of Metal Ions in Archaeological Glass by Abrasive Stripping Square-Wave Voltammetry Using Graphite/Polyester Composite Electrodes

2003

A method for identifying Co, Cu, Sb, Sn, Fe, Zn, and Zr pigments in glasses using square-wave voltammetry as the detection mode is described. It is based on the abrasive attachment of glass microsamples to graphite/polyester composite electrodes. Sample amounts less than 1 μg are used allowing for the study of archaeological samples. In all cases well-defined anodic stripping peaks corresponding to the oxidation of metal deposits generated at potentials ranging from −0.6 to −1.6 V (vs. SCE) are obtained. This response is in agreement with that displayed by the corresponding metal oxides. Quantitative estimates of the relative population of metal ions in glasses are obtained from peak area m…

A Side-by-Side Single Sex Age-Structured Human Population Dynamic Model: Exact Solution and Model Validation

2008

A side-by-side single sex age-structured population dynamic model is presented in this paper. The model consists of two coupled von Foerster-McKendrick-type quasi-linear partial differential equations, two initial conditions, and two boundary conditions. The state variables of the model are male and female population densities. The solutions of these partial differential equations provide explicit time and age dependence of the variables. The initial conditions define the male and female population densities at the initial time, while the boundary conditions compute the male and female births at zero-age by using fertility rates. The assumptions of the nontime-dependence of the death and fe…

Generalized curved beam on elastic foundation solved by Transfer Matrix Method

2011

A solution of space curved bars with generalized Winkler soil found by means of Transfer Matrix Method is presented. Distributed, concentrated loads and imposed strains are applied to the beam as well as rigid or elastic boundaries are considered at the ends. The proposed approach gives the analytical and numerical exact solution for circular beams and rings, loaded in the plane or perpendicular to it. A well-approximated solution can be found for general space curved bars with complex geometry. Elastic foundation is characterized by six parameters of stiffness in different directions: three for rectilinear springs and three for rotational springs. The beam has axial, shear, bending and tor…

On the critical velocities and free vibrations of axially moving elastic webs

2014

Real-time observation of the charge transfer to solvent dynamics

2013

Intermolecular electron-transfer reactions have a crucial role in biology, solution chemistry and electrochemistry. The first step of such reactions is the expulsion of the electron to the solvent, whose mechanism is determined by the structure and dynamical response of the latter. Here we visualize the electron transfer to water using ultrafast fluorescence spectroscopy with polychromatic detection from the ultraviolet to the visible region, upon photo-excitation of the so-called charge transfer to solvent states of aqueous iodide. The initial emission is short lived (similar to 60 fs) and it relaxes to a broad distribution of lower-energy charge transfer to solvent states upon rearrangeme…

La participación de la ciudadanía en los procesos de diseño de las políticas públicas de empleo. El caso del litoral sur de Alicante

2019

La presente investigación tiene como finalidad describir cómo la ciudadanía ha contribuido a la elaboración de un Diagnóstico Territorial de Empleo (DET) promovido por la Generalitat Valenciana, previo al diseño de futuras políticas públicas para el fomento del empleo, en tres municipios alicantinos. Se consiguió a través de una Investigación-Acción-Participación (IAP). Se realizaron talleres participativos y grupos focales que sirvieron para que la ciudadanía conociese de la existencia del proyecto y sus fines, además de aportar su experiencia, opinión y plantear posibles soluciones a la problemática del empleo en estos municipios. Se puede concluir que la ciudadanía está capacitada para a…

Stability of topotecan infusion solutions in polyvinylchloride bags and elastomeric portable infusion devices

1999

Purpose. The purpose of this study was to determine the physicochemical stability of topotecan after reconstitution and after further dilution in two commonly used infusion fluids (0.9% sodium chloride, 5% dextrose) in both polyvinylchloride (PVC) bags and elastomeric portable infusion devices. Methods. Each vial of topotecan (Hycamtin®) was reconstituted with sterile water for injection, yielding a nominal concentration of 1 mg/mL. Topotecan infusion solutions were aseptically prepared by further dilution of reconstituted topotecan solutions with either 0.9% sodium chloride or 5% dextrose in both PVC bags and portable elastomeric infusion devices, in amounts yielding topotecan concentrati…

Gene delivery agents possessing antiradical activity: self-assembling cationic amphiphilic 1,4-dihydropyridine derivatives

2013

Seventeen 1,4-dihydropyridine (1,4-DHP) amphiphiles including differently substituted pyridinium, pyrazinium, N-methyl piperidinium or N-methyl morpholinium moieties as the cationic head-group of the molecule have been designed and synthesised. 1,4-DHP amphiphiles have been earlier proposed as a promising tool for plasmid DNA (pDNA) delivery in vitro. In this work the ability of the 1,4-DHP amphiphiles to self-assemble, to bind pDNA and to transfer it into the cells as well as the cytotoxicity of 1,4-DHP amphiphiles–pDNA complexes was studied. Furthermore, antiradical activity (ARA) of the 1,4-DHP derivatives was determined. We have revealed that all new 1,4-DHP amphiphiles possessed self-a…