Component dynamics in polyvinylpyrrolidone concentrated aqueous solutions

Busselez, Rémi; Arbe, Arantxa; Cerveny, Silvina; Capponi, Sara; Colmenero, Juan; Frick, B.

doi:10.1063/1.4746020

Cited by 42 publications

(46 citation statements)

References 106 publications

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“…The efficiency of PVPP in the control of phenolic oxidation is documented in the literature. The PVPP is an amorphous polymer without physiological activity (BASHA, 2011), used for in vitro establishment of genotypes that is prone to phenolic oxidation (BUSSELEZ et al, 2012). The PVPP acts by complexing phenolic and alkaloids compounds released in response to tissue injury, reducing the toxic effects on the cells (FOLCH-CANO; OLEA-AZAR; SPEISKY, 2013;MALIK et al, 2010;AMIN;JAISWAL, 1988).…”

Section: Resultsmentioning

confidence: 99%

In vitropropagation and acclimatization ofLippia rotundifolia, na endemic species of Brazilian Campos Rupestres

Resende

Bianchetti

Oliveira

et al. 2015

Revista Ciência Agronômica

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-The importance in folk medicine, combined to threats in their environment, becomes necessary to carry out studies involving large-scale propagation of Lippia genus. Although the tissue culture propagation is widely disseminated for medicinal plants, for L. rotundifolia any article was published yet. The present study aimed to establish an efficient protocol for micropropagation of L. rotundifolia. Nodal segments, taken from plants collected in the Espinhaço Range, were disinfected, and cultures were initiated on MS medium with PVPP (1 g L -1), sucrose (3%) and agar (0.7%). The culture were maintained in a growth room at controlled conditions. Disinfestation procedures and the supply of PVPP on culture media resulted in both reduced contamination and phenol oxidation rates, with more than 90% of viable cultures. In the multiplication phase were tried different BAP and NAA combinations supplied to the MS medium. The treatment that resulted in highest multiplication rates was 0.33 M BAP. The effects of NAA were evaluated for in vitro rooting. At 0.44 M, rooting was 70% higher than that observed in the control. The acclimatization was held in trays with substrate, coated with translucent plastic and kept under shade. The plantlets were transferred to the greenhouse after 15 days and transplanted to plant beds after 30 days. The acclimatized plantlets bloomed one year after the transference to field conditions, showing that the in vitro culture did not affect the vegetative and reproductive development, which confirms the potential of micropropagation to reduce the extinction risk of L. rotundifolia.Key words: Micropropagation. In vitro multiplication. In vitro rooting. Ex vitro acclimatization. Biodiversity conservation.RESUMO -A importância na medicina popular, assim como as ameaças em seu ambiente, tornam necessária a realização de estudos envolvendo a propagação em larga escala de plantas do gênero Lippia. Embora a propagação in vitro seja amplamente disseminada para plantas medicinais, nenhum artigo foi publicado ainda com L. rotundifolia. O presente estudo teve como objetivo estabelecer um protocolo eficiente para a micropropagação dessa espécie. Segmentos nodais, retirados de plantas coletadas na Cadeia do Espinhaço, foram desinfetados antes da inoculação em meio MS suplementado com PVPP (1 g L -1), sacarose (3%) e ágar (0,7%). Os tubos de ensaio foram mantidos em sala de crescimento sob condições controladas. O tratamento de desinfestação e a adição de PVPP aos meios de cultura resultaram na redução da infecção microbiológica assim como nas taxas de oxidação fenólica, proporcionando mais de 90% de culturas assépticas e viáveis . Na fase de multiplicação foram testadas diferentes combinações de BAP e ANA adicionadas ao meio MS. O tratamento que resultou em maiores taxas de multiplicação foi de 0,33 M de BAP. Os efeitos do ANA foram avaliados no enraizamento in vitro. A 0,44 M de ANA, o enraizamento foi 70% superior ao observado no controle. A aclimatização foi realizada em bandejas com substrato, rev...

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Section: Resultsmentioning

confidence: 99%

In vitropropagation and acclimatization ofLippia rotundifolia, na endemic species of Brazilian Campos Rupestres

Resende

Bianchetti

Oliveira

et al. 2015

Revista Ciência Agronômica

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“…53 Finally, hydrated polymers and polymer solutions-in particular, microgels-have also recently been investigated by QENS. [54][55][56][57][58][59][60][61][62][63] Studies on concentrated aqueous solutions show that confinement effects also arise -in this case for the minority water component-when the polymer freezes approaching its glass-transition. The component dynamics in these solutions can be selectively monitored by QENS, a task that is not easily achievable by other usually applied experimental approaches like, for example, dielectric spectroscopy.…”

Section: Recent Progress On Polymer Dynamics By Neutron Scatteringmentioning

confidence: 99%

“…Average diffusion coefficients of water in mixtures with PVME, 54 PVP, 55 and amorphous and semicrystalline polyamides copolymers 56 as functions of temperature, compared with that of bulk water. 152 content 55 and the two aforementioned polyamides/water mixtures (≈16 wt % water concentration).…”

Section: Figure 12mentioning

confidence: 99%

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Recent progress on polymer dynamics by neutron scattering: From simple polymers to complex materials

Colmenero

Arbe

2012

J Polym Sci B Polym Phys

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ABSTRACT:The recent (from 2010 onward) contributions of quasielastic neutron scattering techniques (time of flight, backscattering, and neutron spin echo) to the characterization and understanding of dynamical processes in soft materials based on polymers are analyzed. The selectivity provided by the combination of neutron scattering and isotopic-in particular, proton/deuterium-labeling allows the isolated study of chosen molecular groups and/or components in a system. This opportunity, together with the capability of neutrons to provide space/time resolution at the relevant length scales in soft matter, allows unraveling the nature of the large variety of molecular motions taking place in materials of increasing complexity. As a result, recent relevant works can be found dealing with dynamical process which associated characteristic lengths and nature are as diverse as, for example, phenyl motions in a glassy linear homopolymer like polystyrene and the chain dynamics of a polymer adsorbed on dispersed clay platelets. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 51: 2013 KEYWORDS: molecular dynamics; neutron scattering; relaxation POLYMER DYNAMICS AT DIFFERENT LENGTH AND TIME SCALES: FROM SIMPLE POLYMERS TO COMPLEX MATERIALSPolymers are composed of macromolecules which are built up by a large number N of monomer units linked together by covalent bonds. Because of this macromolecular nature, the structural and dynamic properties of polymeric systems strongly depend on a hierarchy of length and time scales. From a structural point of view, the random coil shape of linear polymer chains in the melt and glassy state-proposed by Flory in the 50s 1 -is nowadays well established by small angle neutron diffraction (SANS). At smaller length scales than those characteristic for the chain dimensions, the local arrangements of the atoms give rise to broad maxima in the static structure factor S(Q) also accessible by neutron diffraction. Usually, a first main peak centered at Q-values ≈ 1 . . . 1.5 Å −1 is present. The T-dependence of this maximum, following the expansion coefficient, indicates an interchain origin, that is, it mainly relates to correlations between atoms belonging to different chains (or to the same chain but well separated segments).2 A second peak located at ∼3 Å −1can also be usually found in S(Q). The small value of the associated characteristic length and its weak T-dependence indicate the intrachain nature of the correlations giving rise to this maximum. We also note that the broadening of the Bragg peaks found in polymers reveals a clear amorphous character. In fact, the features shown in S(Q) in polymeric systems are universal for amorphous materials, not only for polymers, and in particular for glass forming systems. Thus, a universal behavior common for all glass forming materials can also be expected in the dynamics, including the observation of the glass transition phenomenon. 3As anticipated, the complexity of amorphous polymers shows up not only in the structural propertie...

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“…9 Some of these, or similar confining systems, have also been studied by using other different experimental techniques, such as broadband dielectric spectroscopy (BDS), [10][11][12][13][14][15] nuclear magnetic resonance (NMR), 16 or a combination of different techniques. [17][18][19][20][21][22] In such studies, most likely due to the broadband frequency range analyzed such crossover for water was either not observed, or attributed to other causes different to that of the fragile-to-strong transition scenario. Thus, no correlation was found by studies of the same sample by QENS and other techniques.…”

Section: Introductionmentioning

confidence: 99%

Cause of the fragile-to-strong transition observed in water confined in C-S-H gel

Monasterio

Jansson

Gaitero

et al. 2013

The Journal of Chemical Physics

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Articles you may be interested inCause of the fragile-to-strong transition observed in water confined in C-S-H gel In this study, the rotational dynamics of hydration water confined in calcium-silicate-hydrate (C-S-H) gel with a water content of 22 wt.% was studied by broadband dielectric spectroscopy in broad temperature (110-300 K) and frequency (10 −1 -10 8 Hz) ranges. The C-S-H gel was used as a 3D confining system for investigating the possible existence of a fragile-to-strong transition for water around 220 K. Such transition was observed at 220 K in a previous study

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Component dynamics in polyvinylpyrrolidone concentrated aqueous solutions

Cited by 42 publications

References 106 publications

In vitropropagation and acclimatization ofLippia rotundifolia, na endemic species of Brazilian Campos Rupestres

In vitropropagation and acclimatization ofLippia rotundifolia, na endemic species of Brazilian Campos Rupestres

Recent progress on polymer dynamics by neutron scattering: From simple polymers to complex materials

Cause of the fragile-to-strong transition observed in water confined in C-S-H gel

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