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1.
Oper Orthop Traumatol ; 32(5): 410-420, 2020 Oct.
Artigo em Alemão | MEDLINE | ID: mdl-32876757

RESUMO

OBJECTIVE: Temporary stabilization of the knee joint in order to minimize soft tissue strain until definitive surgery is possible. INDICATIONS: Bicondylar distal femoral and tibial plateau fractures, additional vascular injury, open fractures (second or third degree), severe soft tissue damage, unicondylar fracture with contralateral ligament tear, (open) knee dislocation, polytrauma. CONTRAINDICATIONS: Unsafe pin placement, severe osteoporosis. SURGICAL TECHNIQUE: Two femoral and tibial pins are connected by two rods and are spanned over the knee with two additional longitudinal rods via a tube-to-tube clamp. Alternatively, this can be facilitated by a direct connection of two rods in case of anteriorly placed femoral pins. A reasonable distance should be kept to open wounds, the fracture, and later operative approaches. The knee is fixed in 5-15° of flexion. POSTOPERATIVE MANAGEMENT: Definitive treatment depending on patient well-being and amenable soft tissue.


Assuntos
Fixadores Externos , Fraturas da Tíbia , Fraturas Expostas , Humanos , Amplitude de Movimento Articular , Fraturas da Tíbia/diagnóstico por imagem , Fraturas da Tíbia/cirurgia , Resultado do Tratamento
2.
J Chem Phys ; 152(18): 184102, 2020 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-32414274

RESUMO

Specialized computational chemistry packages have permanently reshaped the landscape of chemical and materials science by providing tools to support and guide experimental efforts and for the prediction of atomistic and electronic properties. In this regard, electronic structure packages have played a special role by using first-principle-driven methodologies to model complex chemical and materials processes. Over the past few decades, the rapid development of computing technologies and the tremendous increase in computational power have offered a unique chance to study complex transformations using sophisticated and predictive many-body techniques that describe correlated behavior of electrons in molecular and condensed phase systems at different levels of theory. In enabling these simulations, novel parallel algorithms have been able to take advantage of computational resources to address the polynomial scaling of electronic structure methods. In this paper, we briefly review the NWChem computational chemistry suite, including its history, design principles, parallel tools, current capabilities, outreach, and outlook.

3.
Phys Chem Chem Phys ; 21(14): 7321-7329, 2019 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-30896682

RESUMO

We present a systematic study of the dc conductivity of solid polyelectrolyte complexes (PEC) of type xPSS PSS·(1 - xPSS) PDADMA as a function of temperature, and of PSS and water content, respectively. PSS stands for poly(styrenesulfonate) and PDADMA for poly(diallyldimethylammonium). Apart from these polyions, small ions like Na+ and Cl- can be incorporated into the complexes. The amount of small ions and its type (Na+ or Cl-) depend on the PEC composition. We show that, in contrast to dried polyelectrolyte complexes where the chloride ions are macroscopically immobile, Cl- ions become mobile if water is absorbed into the PEC. In PEC with an excess of PDADMA (xPSS < 0.5), hydrated Cl- ions govern the ionic conductivity. On the other hand, in PEC with an excess of PSS (xPSS > 0.5), the conductivity is determined by the sodium ions. For the first time we show that the dependence of the conductivity on composition can be described by power-laws as derived within the framework of the dynamic structure model originally developed for glassy ion conductors by Bunde, Ingram and Maass (J. Non-Cryst. Solids, 1994, 172-174, 1222). This power-law behavior is found in PEC with an excess of Cl- ions as well as in those with an excess of Na+ ions. Also the model predictions concerning the temperature dependence of the power-law exponents on the one hand and the composition dependence of the activation enthalpy on the other hand, are found to be valid. These findings indicate that in polyelectrolyte complexes ions travel via pathways of ion specific sites through the polyelectrolyte matrix. The results on hydrated PEC are compared to those of dry PEC where the dynamic structure model is only applicable for PEC with an excess of PSS (xPSS > 0.5).

4.
Dalton Trans ; 46(38): 12971-12980, 2017 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-28932853

RESUMO

The reactivity of iron-based ring opening polymerization catalysts is compared when the catalyst is in three different oxidation states. Formally iron(i) monoalkoxide complexes 3a (p-methoxyphenoxide) and 3b (neopentoxide) supported by bis(imino)pyridine ligands were synthesized and investigated as catalysts for the ring opening polymerization and copolymerization of various monomers. For most monomers, 3a and 3b were superior catalysts compared to analogous, formally iron(ii) and iron(iii) complexes (1a/1b and 2a/2b, respectively) for the ring opening polymerization of various cyclic ester and cyclic carbonate monomers. Experimental and computational investigation into the electronic structures of 3a and 3b revealed that they are most accurately described as containing a high spin iron(ii) center that is antiferromagnetically coupled to a singly reduced bis(imino)pyridine ligand. This electronic structure leads to increased electron density near the metal center without modulating the apparent metal oxidation state, which results in superior catalytic performance for the more highly reduced 3a and 3b compared to the increasingly more oxidized complexes (i.e.1a/1b and 2a/2b, respectively) in ring opening polymerization reactions. These findings have significant ramifications for the emerging field of redox-switchable polymerization catalysis.

5.
Dalton Trans ; 46(18): 6128, 2017 05 09.
Artigo em Inglês | MEDLINE | ID: mdl-28452387

RESUMO

Correction for 'Atomic layer deposition of Cu(i) oxide films using Cu(ii) bis(dimethylamino-2-propoxide) and water' by J. R. Avila, et al., Dalton Trans., 2017, DOI: .

6.
Dalton Trans ; 46(18): 5790-5795, 2017 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-28406498

RESUMO

To grow films of Cu2O, bis-(dimethylamino-2-propoxide)Cu(ii), or Cu(dmap), is used as an atomic layer deposition precursor using only water vapor as a co-reactant. Between 110 and 175 °C, a growth rate of 0.12 ± 0.02 Å per cycle was measured using an in situ quartz crystal microbalance (QCM). X-ray photoelectron spectroscopy (XPS) confirms the growth of metal-oxide films featuring Cu(i).

7.
Allergol Select ; 1(1): 85-95, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-30402607

RESUMO

The increasing prevalence of asthma, hay fever, and allergic sensitization in Western Germany after east-west division in 1949 and their rapid increase in East German children after re-unification in 1990 are strong indications for the role of life-style and/or environmental factors in the development of atopic diseases. Obviously, the perinatal period is crucial for priming the immune system. Therefore, explorations of determinants of atopic diseases need pregnancy or birth cohorts as the most appropriate epidemiological study designs. This review presents the design and selected results of the two German birth cohorts GINIplus and LISAplus. GINIplus and LISAplus recruited 5.991 and 3.097 healthy, term newborns, respectively, from Munich, Wesel, Leipzig, and Bad Honnef. Approximately 55% could be followed for the first 10 years. We analyzed the natural course of atopic diseases and the role of life-style, environmental, and genetic factors for disease onset, intermediate phenotypes, and genes involved in detoxification and oxidative stress. The results of these two large birth cohorts contributed substantially to the understanding of atopic diseases and their determinants.

8.
J Res Natl Inst Stand Technol ; 121: 367-371, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-34434627

RESUMO

Tracking climate variables at the levels of precision and accuracy required to detect global change requires satellite sensors to make highly consistent measurements that can be compared to measurements made at different times and with different instruments. Gaps in climate data records, such as those resulting from launch delay or instrument failure, and inconsistencies in radiometric scales between satellites can introduce unnecessary measurement error and thus undermine the credibility of fundamental climate data records. To address these issues, leading experts in satellite remote sensing and lunar observation and modeling assembled at the National Institute of Standards and Technology from 12-15 May 2012 for a workshop to discuss the utility of and strategies for using the Moon to calibrate satellite remote sensing measurements. This report summarizes the outcome of the workshop, including suggested steps to maximize the value of the Moon as an exoatmospheric calibration source for satellite remote sensing.

9.
PLoS One ; 10(12): e0143208, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26636762

RESUMO

BACKGROUND: Despite the clinical benefit of whole brain radiotherapy (WBRT), patients and physicians are concerned by the long-term impact on cognitive functioning. Many studies investigating the molecular and cellular impact of WBRT have used rodent models. However, there has not been a rodent protocol comparable to the recently reported Radiation Therapy Oncology Group (RTOG) protocol for WBRT with hippocampal avoidance (HA) which is intended to spare cognitive function. The aim of this study was to develop a hippocampal-sparing WBRT protocol in Wistar rats. METHODS: The technical and clinical challenges encountered in hippocampal sparing during rat WBRT are substantial. Three key challenges were identified: hippocampal localization, treatment planning, and treatment localization. Hippocampal localization was achieved with sophisticated imaging techniques requiring deformable registration of a rat MRI atlas with a high resolution MRI followed by fusion via rigid registration to a CBCT. Treatment planning employed a Monte Carlo dose calculation in SmART-Plan and creation of 0.5 cm thick lead blocks custom-shaped to match DRR projections. Treatment localization necessitated the on-board image-guidance capability of the XRAD C225Cx micro-CT/micro-irradiator (Precision X-Ray). Treatment was accomplished with opposed lateral fields with 225 KVp X-rays at a current of 13 mA filtered through 0.3 mm of copper using a 40x40 mm square collimator and the lead blocks. A single fraction of 4 Gy was delivered (2 Gy per lateral field) with a 41 second beam on time per field at a dose rate of 304.5 cGy/min. Dosimetric verification of hippocampal sparing was performed using radiochromic film. In vivo verification of HA was performed after delivery of a single 4 Gy fraction either with or without HA using γ-H2Ax staining of tissue sections from the brain to quantify the amount of DNA damage in rats treated with HA, WBRT, or sham-irradiated (negative controls). RESULTS: The mean dose delivered to radiochromic film beneath the hippocampal block was 0.52 Gy compared to 3.93 Gy without the block, indicating an 87% reduction in the dose delivered to the hippocampus. This difference was consistent with doses predicted by Monte Carlo dose calculation. The Dose Volume Histogram (DVH) generated via Monte Carlo simulation showed an underdose of the target volume (brain minus hippocampus) with 50% of the target volume receiving 100% of the prescription isodose as a result of the lateral blocking techniques sparing some midline thalamic and subcortical tissue. Staining of brain sections with anti-phospho-Histone H2A.X (reflecting double-strand DNA breaks) demonstrated that this treatment protocol limited radiation dose to the hippocampus in vivo. The mean signal intensity from γ-H2Ax staining in the cortex was not significantly different from the signal intensity in the cortex of rats treated with WBRT (5.40 v. 5.75, P = 0.32). In contrast, the signal intensity in the hippocampus of rats treated with HA was significantly lower than rats treated with WBRT (4.55 v. 6.93, P = 0.012). CONCLUSION: Despite the challenges of planning conformal treatments for small volumes in rodents, our dosimetric and in vivo data show that WBRT with HA is feasible in rats. This study provides a useful platform for further application and refinement of the technique.


Assuntos
Irradiação Craniana/métodos , Hipocampo/efeitos da radiação , Animais , DNA/efeitos da radiação , Fracionamento da Dose de Radiação , Hipocampo/fisiopatologia , Radioterapia de Intensidade Modulada , Ratos , Ratos Wistar , Resultado do Tratamento
10.
Phys Chem Chem Phys ; 17(35): 22552-6, 2015 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-26280312

RESUMO

We analyze the scaling properties of pH-dependent shear modulus spectra of complex coacervates made of weak polyanions and strong polycations. For the first time, we report on a "time-pH superposition principle". This principle implies that the charge density in complex coacervates made of not fully charged polyions only influences the time scale of the relaxation dynamics, but not the mechanisms of the underlying dynamics.

11.
Chem Sci ; 6(11): 6482-6495, 2015 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-30090267

RESUMO

During the last 10-15 years, dynamic nuclear polarization (DNP) has evolved as a powerful tool for hyperpolarization of NMR and MRI nuclides. However, it is not as well appreciated that solution-state dynamic nuclear polarization is a powerful approach to study intermolecular interactions in solution. For solutions and fluids, the 1H nuclide is usually dominated by an Overhauser dipolar enhancement and can be significantly increased by decreasing the correlation time (τc) of the substrate/nitroxide interaction by utilizing supercritical fluids (SF CO2). For molecules containing the ubiquitous 13C nuclide, the Overhauser enhancement is usually a profile of both scalar and dipolar interactions. For carbon atoms without an attached hydrogen, a dipolar enhancement usually dominates as we illustrate for sp2 hybridized carbons in the fullerenes, C60 and C70. However, the scalar interaction is dependent on a Fermi contact interaction which does not have the magnetic field dependence inherent in the dipolar interaction. For a comprehensive range of molecular systems we show that molecules that exhibit weakly acidic complexation interaction(s) with nitroxides provide corresponding large scalar enhancements. For the first time, we report that sp hybridized (H-C) alkyne systems, for example, the phenylacetylene-nitroxide system exhibit very large scalar dominated enhancements. Finally, we demonstrate for a wide range of molecular systems that the Fermi contact interaction can be computationally predicted via electron-nuclear hyperfine coupling and correlated with experimental 13C DNP enhancements.

12.
Eur J Clin Nutr ; 67(8): 855-62, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23612517

RESUMO

OBJECTIVE: To develop a prediction model that quantifies the risk of being overweight at 10 years of age. SUBJECTS/METHODS: In total, 3121 participants from the GINIplus (German Infant Nutritional Intervention plus environmental and genetic influences on allergy development) and LISAplus (Influences of Lifestyle-Related Factors on the Immune System and the Development of Allergies in Childhood plus Air Pollution and Genetics) German birth cohorts were recruited. We predicted standardized body mass index (BMI) at 10 years of age using standardized BMIs from birth to 5 years. Parental education, family income and maternal smoking during pregnancy were considered as covariates. Linear and logistic regression models were used to evaluate the impact of risk factors on BMI and on being overweight at 10 years of age, respectively. RESULTS: Birth weight, standardized BMI at 5 years (60-64 months) (ß=0.77; 95% confidence interval (CI): 0.73-0.81) and maternal smoking during pregnancy were positively associated with standardized BMI at 10 years of age. Standardized BMI and overweight at 5 years were strongest predictors of being overweight at 10 years. Conversely, high parental education conferred a protective effect (ß=-0.15; 95% CI: -0.29 to -0.01). Being overweight at 5 years (60-64 months) increased the risk of being overweight at 10 years of age with odds ratios above 10. Among children who were predicted to be overweight at 10 years, cross-validation results showed that 76.8% of female subjects and 68.1% of male subjects would be overweight at 10 years of age. CONCLUSION: BMI and being overweight at 5 years of age are strong predictors of being overweight at 10 years of age. The effectiveness of targeted interventions in children who are overweight at 5 years of age should be explored.


Assuntos
Peso ao Nascer , Índice de Massa Corporal , Obesidade/etiologia , Pais , Efeitos Tardios da Exposição Pré-Natal , Fatores Etários , Criança , Pré-Escolar , Estudos de Coortes , Escolaridade , Feminino , Alemanha , Humanos , Masculino , Razão de Chances , Sobrepeso/complicações , Gravidez , Fatores de Risco , Fatores Sexuais , Fumar
13.
J Res Natl Inst Stand Technol ; 118: 396-402, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-26401440

RESUMO

We report a measurement of lunar spectral irradiance with an uncertainty below 1 % from 420 nm to 1000 nm. This measurement uncertainty meets the stability requirement for many climate data records derived from satellite images, including those for vegetation, aerosols, and snow and ice albedo. It therefore opens the possibility of using the Moon as a calibration standard to bridge gaps in satellite coverage and validate atmospheric retrieval algorithms. Our measurement technique also yields detailed information about the atmosphere at the measurement site, suggesting that lunar observations are a possible solution for aerosol monitoring during the polar winter and can provide nighttime measurements to complement aerosol data collected with sun photometers. Our measurement, made with a novel apparatus, is an order of magnitude more accurate than the previous state-of-the-art and has continuous spectral coverage, removing the need to interpolate between filter passbands.

14.
Artigo em Alemão | MEDLINE | ID: mdl-22736169

RESUMO

Numerous chronic diseases in childhood and adulthood have their origins in perinatal life and are potentially influenced by trans-generational epigenetic processes. Therefore, prospective birth cohorts can substantially contribute to our knowledge about the etiology of diseases including modifiable risk factors. The two population-based German birth cohorts GINIplus and LISAplus aim to describe the natural course of chronic diseases and intermediate phenotypes in childhood and its determinants, and to identify potential genetic effect modifications. In the mid-1990s, 5,991 (GINIplus) and 3,097 (LISAplus) healthy, term newborns were recruited for long-term follow-up in four regions of Germany. The follow-up rate for the first 10 years was about 55%. We analyzed the growth and development of overweight, infections and allergic diseases, mental and oral health, metabolic and inflammatory parameters and the role of potential risk factors including genetics. The results of these two birth cohorts substantially contribute to the current knowledge about the natural course of these health parameters. These data were included in many international projects and consortia for purposes of international comparisons of prevalence and consistency of findings, and to increase the power of the analyses.


Assuntos
Estudos de Coortes , Doenças do Recém-Nascido/epidemiologia , Parto , Feminino , Alemanha/epidemiologia , Humanos , Recém-Nascido , Masculino , Prevalência , Fatores de Risco
15.
Water Sci Technol ; 65(9): 1648-53, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22508128

RESUMO

Membrane bioreactor (MBR) technology is a very reliable and extensively tested solution for biological wastewater treatment. Nowadays, separate treatment of highly polluted wastewater streams especially from hospitals and other health care facilities is currently under investigation worldwide. In this context, the MBR technology will play a decisive role because an effluent widely cleaned up from solids and nutrients is absolutely mandatory for a subsequent further elimination of organic trace pollutants. Taking hospital wastewater as an example, the aim of this study was to investigate to what extent MBR technology is an adequate 'pre-treatment' solution for further elimination of trace pollutants. Therefore, we investigated - within a 2-year period - the performance of a full-scale hospital wastewater treatment plant (WWTP) equipped with a MBR by referring to conventional chemical and microbiological standard parameters. Furthermore, we measured the energy consumption and tested different operating conditions. According to our findings the MBR treatment of the hospital wastewater was highly efficient in terms of the removal of solids and nutrients. Finally, we did not observe any major adverse effects on the operation and performance of the MBR system which potentially could derive from the composition of the hospital wastewater. In total, the present study proved that MBR technology is a very efficient and reliable treatment approach for the treatment of highly polluted wastewater from hospitals and can be recommended as a suitable pre-treatment solution for further trace pollutant removal.


Assuntos
Reatores Biológicos , Filtração/instrumentação , Hospitais , Eliminação de Resíduos de Serviços de Saúde/métodos , Eliminação de Resíduos Líquidos/métodos , Alemanha , Esgotos , Poluentes da Água , Poluição da Água/prevenção & controle , Purificação da Água/métodos
16.
Phys Rev Lett ; 107(2): 028301, 2011 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-21797645

RESUMO

We analyze the scaling properties of the ac conductivity spectra of ion-conducting polyelectrolyte complexes of different compositions. Spectra were taken at ambient temperature but at different relative humidities. For the first time, we report on a scaling principle for conductivity spectra termed "time-humidity-superposition principle" in analogy with the well-known time-temperature-superposition principle. This model-free scaling holds for different materials over several decades in frequency. It implies that the hydration is activating ion motion over short and long distances in a similar general way, a concept so far only established for thermal energy.

17.
Water Sci Technol ; 63(1): 66-71, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21245555

RESUMO

Membrane Bioreactors (MBR) are a very attractive option for the treatment of hospital wastewater and elimination of pharmaceuticals in high density urban areas. The present investigation showed that, depending on the substance, between 19% and 94% of the level of antibiotics found in the environment originate from hospitals. Because of their ecotoxic potential, hospital wastewaters can have a significant impact on the environment. The segregation of these wastewaters and their separate treatment at the source can reduce the entry of drugs in waterways and enable water reuse after adequate polishing treatment processes.


Assuntos
Reatores Biológicos , Hospitais , Resíduos Industriais , Membranas Artificiais , Urbanização , Poluentes Químicos da Água/isolamento & purificação
18.
Allergy ; 66(1): 68-75, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20716321

RESUMO

BACKGROUND: Day care centre attendance is much more common in East than in West Germany. Although there is evidence that early day care might be protective against atopic diseases, several studies have shown a higher prevalence of childhood eczema in East Germany compared to West Germany. OBJECTIVES: To compare prevalence and cumulative incidence of eczema in a birth cohort study in East and West Germany and to identify risk factors that are associated with eczema, which might explain regional differences. METHODS: We used data from the ongoing population-based birth cohort study Influence of Life-style factors on the development of the Immune System and Allergies in East and West Germany Plus the influence of traffic emissions and genetics. In 1997, 3097 children from study areas in East and West Germany were recruited. Cumulative incidence and 1-year prevalences of eczema up to the age of 6 years were determined from yearly questionnaires. Cox regression and generalized estimating equations/logistic regression were used to quantify regional differences and to identify risk factors that might explain them. RESULTS: Prevalence and incidence of eczema were higher in children living in East Germany than those living in West Germany. We identified 11 risk factors that showed significant regional differences. From these factors, only 'day care attendance during the first 2 years of life' was significantly associated with eczema (odds ratio 1.56, 95% confidence interval CI 1.31-1.86). The regional differences in eczema could be explained by differences in early day care utilization. CONCLUSION: Day care centre attendance is associated with an increased prevalence and incidence of eczema. Regional differences in eczema prevalence could be explained by regional differences in utilization of early day care.


Assuntos
Absenteísmo , Creches/estatística & dados numéricos , Eczema/epidemiologia , Criança , Pré-Escolar , Estudos de Coortes , Feminino , Alemanha Oriental/epidemiologia , Alemanha Ocidental/epidemiologia , Pesquisas sobre Atenção à Saúde , Humanos , Incidência , Lactente , Estilo de Vida , Masculino , Prevalência , Fatores de Risco , Meio Social , Inquéritos e Questionários
19.
Plant Dis ; 95(10): 1319, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30731680

RESUMO

Iris yellow spot virus (IYSV; family Bunyaviridae, genus Tospovirus) is becoming an increasingly important constraint to the production of bulb and seed onions (Allium cepa L.) in many onion-growing regions of the continental United States and the world (4). During an evaluation of onion germplasm for susceptibility to IYSV, six other Allium species (A. altaicum, A. galanthum, A. roylei, A. schoenoprasum, A. tuberosum, and A. vavilovii) were also evaluated under natural field conditions. In July 2010, symptoms suggestive of IYSV infection (straw-colored necrotic lesions) were observed on leaves of these Allium spp. in experimental plots in Las Cruces, NM. IYSV was detected in symptomatic leaves of A. altaicum, A. vavilovii, A. tuberosum, A. schoenoprasum and A. roylei with a commercially available ELISA kit (Agdia Inc., Elkhart, IN). IYSV infection was confirmed by reverse transcription (RT)-PCR with forward and complementary primers 5'-CTCTTAAACACATTTAACAAGCAC-3' and 5'-TAAAACAAACATTCAAACAA-3' flanking the nucleocapsid (N) gene encoded by the small RNA of IYSV as previously described (1,3). Amplicons, approximately 1.1 kb long, were obtained from all symptomatic Allium spp. samples but not from healthy samples or water controls. Sequencing of selected amplicons confirmed IYSV infection. The highest nucleotide identity of 98% was shared with IYSV isolates from Japan (GenBank Accession No. AB180921). A. altaicum, A. vavilovii, and A. pskemense were previously reported from Washington to be susceptible to IYSV (2). Current findings expand the list of Allium spp. that are susceptible to IYSV and underscores the need for continued screening of other members of the genus to find sources of resistance to IYSV. References: (1) H. R. Pappu et al. Arch. Virol. 151:1015, 2006. (2) H. R. Pappu et al. Plant Dis. 90:378, 2006. (3) H. R. Pappu et al. Plant Dis. 92:588, 2008. (4) H. R. Pappu et al. Virus Res. 141:219, 2009.

20.
Phys Rev Lett ; 102(25): 255901, 2009 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-19659097

RESUMO

For the first time, we analyze ac conductivity spectra of various dried ionically cross-linked polyelectrolyte complexes in terms of the time-temperature superposition principle. The temperature-dependent spectra of some complexes show scaling properties that are distinctly different from the behavior of all other ion-conducting materials reported so far, but in agreement with model predictions by Roling [B. Roling, Phys. Chem. Chem. Phys. 3, 5093 (2001).10.1039/b105094j]. We conclude that the dc conductivity of the investigated PEC is always governed by the Na+ ions, even in complexes with excess of polycations and chloride anions.

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