Interactions between cations and sugars. III. Free energies, enthalpies, and entropies of association of Ca2+, Sr2+, Ba2+, La3+, Gd3+ with D-ribose in water at 25 °C

1987 ◽  
Vol 65 (11) ◽  
pp. 2656-2660 ◽  
Author(s):  
Alfredo Maestre Alvarez ◽  
Nicole Morel-Desrosiers ◽  
Jean-Pierre Morel

The standard enthalpies of transfer of ribose and arabinose from water to aqueous solutions of electrolytes (CaCl2, SrCl2, BaCl2, LaCl3, and GdCl3) have been measured at 25 °C. A method is described to calculate from these data the equilibrium constant and the enthalpy for the association between the cations and the complexing isomers of ribose. Mean values relative to these isomers are given: the constants vary from 2.0 to 4.3 and the enthalpies from −5.9 to −17.9 kJ mol−1 for the different cations studied. The thermodynamic properties of association are not related to the size nor to the charge of the complexed cation in a simple way. On the other hand, the enthalpies of reaction are linearly correlated to the entropies of reaction.

1983 ◽  
Vol 48 (8) ◽  
pp. 2327-2334
Author(s):  
Otakar Söhnel ◽  
Petr Novotný ◽  
Zdeněk Šolc

Two methods are given for assessment of density of binary aqueous solutions of electrolytes; one is based on partial molar volume of the dissolved electrolyte at infinite dilution, and the other is based on additivity of apparent molar volumes at a given concentration. The density estimates of aqueous solutions by means of the two methods are compared with experimental values for some electrolytes of the type 1-1 to 4 and 2-2. In all cases the estimates agree with experimental densities up to concentrations of the saturated solutions.


2013 ◽  
Vol 300-301 ◽  
pp. 1352-1355 ◽  
Author(s):  
Futo Tsumuji ◽  
Daiki Hoshino ◽  
Shou Ogihara ◽  
Zong Fan Duan ◽  
Yutaro Suzuki ◽  
...  

In this work, a PPy actuator was fabricated by galvanostatic electropolymerization. The electrochemical deformation behaviors of the PPy actuator were investigated in aqueous solutions of an electrolyte, lithium bis(trifluoromethanesulphonyl)imide (LiTFSI), containing different concentrations of methanol. Marked improvement of the actuating strain of approximately 9% was achieved when the actuator was driven by a potential between –1 and 1 V in the LiTFSI electrolyte containing 40 to 50% of methanol under a load stress of 0. 3 MPa. On the other hand, the actuator functioned in the electrolyte solutions containing more than 60% of methanol showed rapid decrease of the actuating strain and the electrochemical creep after repeated actuations. Possible mechanisms for these behaviors were discussed.


1982 ◽  
Vol 60 (10) ◽  
pp. 1241-1246 ◽  
Author(s):  
T. Trippenbach ◽  
C. Gaultier ◽  
L. Cooper

Effects of chest compressions on the pattern of breathing were studied in pentobarbital anaesthetized 9- to 11-day-old kittens before and after vagotomy. The chest was compressed by means of a micrometer at three levels (T1–4, T6–8, T9–11). In intact and vagotomized kittens, the group mean values of inspiratory time (tI), expiratory (tE) time, peak amplitude of the integrated phrenic activity (PHR) and its rate of rise (PHR/tI) during compressions were not different from those of the control breaths. On the other hand, in intact kittens during chest compressions variability of all the measured variables significantly increased. In the vagotomized kittens, variability of parameters other than inspiratory time was unaffected. Nevertheless we cannot exclude contribution of extravagal receptors in control of tE. The tE effects could be masked by the increased variability of the control value in vagotomized kittens. The effects of chest compression on the integrated phrenic activity were mostly dependent on the intact vagal feedback.


1998 ◽  
Vol 18 (4) ◽  
pp. 765-789 ◽  
Author(s):  
HENK BRUIN ◽  
GERHARD KELLER

For S-unimodal maps $f$, we study equilibrium states maximizing the free energies $F_t(\mu) := h(\mu) - t\int \log|f'|\,d\mu$ and the pressure function $P(t):=\sup_\mu F_t(\mu)$. It is shown that if $f$ is uniformly hyperbolic on periodic orbits, then $P(t)$ is analytic for $t\approx 1$. On the other hand, examples are given where no equilibrium states exist, where equilibrium states are not unique and where the notions of equilibrium state for $t=1$ and of observable measure do not coincide.


Retos ◽  
2019 ◽  
pp. 83-88
Author(s):  
Raúl Baños ◽  
Emilio Arrayales

El objetivo de este estudio fue analizar como el clima motivacional creado por el docente de educación física (EF) puede predecir la satisfacción o el aburrimiento durante la clase. Participaron 680 estudiantes de Educación Secundaria Obligatoria (ESO) de las provincias de la Región de Murcia y Alicante (España) (339 chicos, 341 chicas; Medad = 14.83, DT = 1.45). Se utilizó un cuestionario compuesto por los siguientes instrumentos: Perceptions of Teahcer´s Emphassion Goals Questionnaire (PTEGQ), y Sport Satisfacción Instrument - PE (SSI-PE). Se realizaron análisis descriptivos, de correlación y regresión lineal simple con el SPSS v.22. Los resultados muestran valores medios altos en el clima de maestría y bajos en evitación-rendimiento. Con respecto al SSI-PE, los valores de la satisfacción en la clase de EF fueron altos y en aburrimiento medios. Por otro lado, el clima de maestría y aprobación social predijeron de forma positiva la satisfacción en la EF. Por su parte, el clima de evitación al rendimiento predijo de manera positiva el aburrimiento y el clima de maestría lo predijo de manera negativa. Los resultados obtenidos demuestran la importancia de crear sesiones con un clima de aprendizaje enfocado hacia la aprobación social y la maestría, ya que se relacionan con sensaciones de disfrute y evitar el clima de evitación-rendimiento.Abstract. The aim of this study was to analyze how the motivational climate created by the physical education teacher (PE) can predict satisfaction or boredom during class. 680 students of Compulsory Secondary Education from the provinces of the Region of Murcia and Alicante (Spain) was participated (339 boys, 341 girls, Mage = 14.83, SD = 1.45). A questionnaire composed by the following instruments Perceptions of Teachers' Emphasis Goals Questionnaire (PTEGQ) and Sport Satisfaction Instrument - PE (SSI-PE) was used. Descriptive, correlation and simple linear regression analyzes were performed with the SPSS v.22 software. The results show high mean values in the mastery climate and low mean values in the performance-avoidance. Regarding to SSI-PE, the values of satisfaction obtained in the PE class were high and in boredom were average. On the other hand, the mastery climate and social approval predicted positively the satisfaction in PE. On the other hand, the performance avoidance climate predicted positively the boredom and the mastery climate predicted it in a negative way. The results show the importance to create sessions with a learning climate focused on social approval and mastery, as they are related with feelings of enjoyment and avoid climates of avoidance-performance.


1999 ◽  
Vol 14 (4) ◽  
pp. 1178-1180 ◽  
Author(s):  
Shin-Ichiro Katahira ◽  
Kenji Yasue ◽  
M. Inagaki

The intercalation reaction of ε-caprolactam anion (ε–CL-) into hydrotalcite heated up to 500 °C to expel in its double hydroxide gallery and also that of ε-caprolactam cation (ε–CL+) into mica were successfully performed in their aqueous solutions. The intercalation reaction of ε–CL- into 500 °C heated hydrotalcite was completed within 1 h at 60 °C, and the resultant intercalation compound had the interlayer spacing of 0.77 nm. The intercalation of ε–CL+ into mica, on the other hand, proceeded rather slowly in two steps, which was due to the presence of two species, Na+ and hydrated Na+ in the mica gallery, and gave the intercalation compound with the interlayer spacing of 1.47 nm.


2010 ◽  
Vol 5 (1) ◽  
pp. 98-105
Author(s):  
Gheorghe Nemtoi ◽  
Florica Ionica ◽  
Tudor Lupascu ◽  
Alexandru Cecal

The dissolution of the iron from steel was observed by drawing the cyclic voltammetry (CV) for the systems consisting of the solution resulted when the alloy sample was immersed in HNO3, H2SO4, and HCl, aqueous solutions on platinum disk electrode (PtDE). The presence of some redox processes can be observed only in HNO3 which confirms the complexity of the mechanism of Fe dissolution in this acid. On the other hand, there were manufactured electrodes of steel samples taken into experiment achieving the corrosion characteristics in the media mentioned above.


1998 ◽  
Vol 16 (6) ◽  
pp. 493-502 ◽  
Author(s):  
Mahmoud A. Zarraa

The ability of scrap rubber to adsorb the three metal ions, copper, cadmium and zinc, in single-component and multi-component mixtures in aqueous solutions has been studied. A comparison has been made between the single-component saturation uptake and the multi-component uptakes. The experimental results were fitted to the Langmuir, Freundlich and Redlich–Peterson isotherms. The correlation coefficients obtained from plotting these isotherms gave a measure of the conformity of the data to a linear trend and corresponded to a perfect fit. The isotherms indicated a competitive uptake, with copper being preferentially adsorbed by scrap rubber in multi-component solutions. The capacity of scrap rubber for the single-component metals was in the order: Cd > Cu > Zn. On the other hand, the order of preference of scrap rubber for metals in multi-component mixtures was: Cu > Cd > Zn.


QJM ◽  
2020 ◽  
Vol 113 (Supplement_1) ◽  
Author(s):  
E A Zaky ◽  
D M A Elnasharty ◽  
R M Elhossiny

Abstract Background The diagnosis and treatment of cancer are a stressful and threatening experience, which has tremendous impact on children and their families. As advances in cancer care have led to more treatment options and longer survival for cancer patients, a focus on quality of life for patients and their families has gained. Objectives The aim of this study was to evaluate the psychosocial aspects of children with different types of pediatric cancer (newly diagnosed as well as survivors), their parents, and sibs in comparison with those with normal children. Patients and Methods This study comprised 60 children, their sibs and caregivers. They were classified into three groups. Group I which comprised 20 newly diagnosed children with cancer, their caregivers and sibs, group II which comprised 20 cancer survivors children, their caregivers and sibs, group III which comprised 20 clinically healthy children, their caregivers and sibs. All children and their sibs in this study were subjected to full history taking, thorough clinical examination, assessment of socioeconomic standard, assessment of pediatric quality of life, a battery of psychometric tests included pediatric checklist, anxiety, depression, and self- esteem scores. All caregivers were subjected to record of demographic variable, assessment of socio-economic level, assessment of anxiety, depression, and isolation score, assessment of stress and burden related to the disease itself, if any, using standardized questionnaire and assessment of quality of life. Results Mean value of DS was significantly higher (P < 0.05) in newly diagnosed cancer children and survivors compared to controls while AS and PCLS was only significantly higher (P < 0.05) in newly diagnosed cancer children compared to controls. On the other hand, mean value of IQ of newly diagnosed cancer children and survivors was significantly than controls(P < 0.05); Mean values of Child as well as the Parental Total HRQL were significantly lower in newly diagnosed and survivors compared to controls (P < 0.05) with the former significantly lower than the later. In studied sib groups, AS was significantly higher in newly diagnosed compared to survivors and controls (P < 0.05), while PCLS was only significantly higher when newly diagnosed compared to survivors. In studied parental groups, mean values of DS, AS, and SS were significantly higher(P,0.05) in newly diagnosed compared to survivors and controls. Meanwhile, IS was significantly higher in newly diagnosed compared to controls. Newly diagnosed children with cancer, their parents and sibs had significantly lower mean values of all Child HRQL subcategories. On the other hand, survivors showed only significantly lower physical and social subcategories compared to controls. In studied sib groups only sibs of newly diagnosed patients and those of survivors, had significantly lower mean value of social subcategory compared to controls. Conclusion The current study showed that newly diagnosed cancer children had severe impact on their psychosocial aspects as well as their HRQL compared to controls while survivors showed a much lesser effects. On the other hand, sibs were mainly affected socially while parents were extremely affected.


1990 ◽  
Vol 45 (8) ◽  
pp. 995-998
Author(s):  
A. Lux ◽  
M. Stockhausen

AbstractThe dielectric relaxation of water rich aqueous solutions of ethanol, ehtylene glycol, glycerol, diethylene glycol, 1,2-butanediol, 1,3-butanediol and 1,4-butanediol has been measured at 20 °C. In all cases the fitting of the data by a sum of Debye type spectral components allows for two description modes which can be interpreted as a collective alteration of the water relaxation or, on the other hand, as formation of a microheterogenous solution where "affected" and "unaffected" water becomes discernible


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