Wyniki wyszukiwania - Biblioteka Nauki

1

Influence of alcohol on mechanical and electrical properties of thin organic films

100%

Kopáni M. , Weis M.

Open Physics

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2007

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tom 5

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nr 3

405-415

EN

Stability of organic materials properties is essential for further applications and was intensely investigated in last few decades. The aim of this study is to detect the structural changes of dipalmitoyl-phosphatidylcholine (DPPC) monolayer as a model system of organic material under influence of alcohols solutions. As subphases of monolayers (Langmuir films), pure water, ethanol and methanol solutions were used. For detection of changes in charge states of the molecules as well as relation with structural and conformational changes, a contactless method employing Maxwell’s displacement currents (MDC) was used. In DPPC monolayer on the subphase of methanol-water, a gradual absorption of methanol molecules into the layer can appear. In DPPC monolayer on the subphase of ethanol-water adsorption of ethanol molecules on the layer can be observed. Influence of alcohols results in a significant change of mechanical and electrical properties as well as in the stability of thin films.

2

Phase equilibria experiments and calculations for carbon dioxide + methanol binary system

88%

Secuianu C. , Feroiu V. , Geană D.

Open Chemistry

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2009

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tom 7

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nr 1

1-7

EN

Vapor-liquid equilibria (VLE) data for the carbon dioxide + methanol system was measured at 293.15, 298.15, 310.15, and 323.15 K. Phase behavior measurements were made in a high-pressure visual cell with variable volume, based on the static-analytic method. The pressure range under investigation was between 4.8 and 95.1 bar. The Soave-Redlich-Kwong (SRK)-EOS coupled with Huron-Vidal (HV) mixing rules and a reduced UNIQUAC model, was used in a semi-predictive approach, in order to represent the phase behavior (critical curve, isothermal VLE) of the system. The topology of the phase behavior of the carbon dioxide + methanol system is satisfactory predicted with the SRK/HV-residual UNIQUAC model. [...]

3

Visual evoked potentials in patients after methanol poisoning

75%

Urban P. , Zakharov S. , Diblík P. , Pelclová D. , Ridzoň P.

International Journal of Occupational Medicine and Environmental Health

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2015

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tom 29

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nr 3

471-478

EN

Objectives We report the results of the visual evoked potentials (VEP) examination in patients after severe poisoning by methanol. Material and Methods The group of 47 patients (38 males and 9 females) was assembled out of persons who survived an outbreak of poisoning by the methanol adulterated alcohol beverages, which happened in the Czech Republic in 2012–2013. The visual evoked potentials examination was performed using monocular checkerboard pattern-reversal stimulation. Two criteria of abnormality were chosen: missing evoked response, and wave P1 latency > 117 ms. Non-parametric statistical methods (median, range, and the median test) were used to analyze factors influencing the VEP abnormality. Results The visual evoked potential was abnormal in 20 patients (43%), 5 of them had normal visual acuity on the Snellen chart. The VEP abnormality did not correlate significantly with initial serum concentrations of methanol, formic acid or lactate; however, it showed statistically significant inverse relation to the initial serum pH: the subgroup with the abnormal VEP had significantly lower median pH in comparison with the subgroup with the normal VEP (7.16 vs. 7.34, p = 0.04). The abnormality was not related to chronic alcohol abuse. Conclusions The visual evoked potentials examination appeared sensitive enough to detected even subclinical impairment of the optic system. Metabolic acidosis is likely to be the key factor related to the development of visual damage induced by methanol. The examination performed with a delay of 1–9 months after the poisoning documented the situation relatively early after the event. It is considered as a baseline for the planned long-term follow-up of the patients, which will make it possible to assess the dynamics of the observed changes, their reversibility, and the occurrence of potential late sequelae.

4

Phytochemical Screening and Antimicrobial Activity of Ethanol and Methanol Extracts of Lantana camara Leaf

75%

Ezebo R. O. , Okonkwo C. C. , Ozoh C. N. , Nwankwo C. A. , Nwafor E. C. , Esimai B. G. , Achonye C. C. , Obienyem J. N.

World News of Natural Sciences

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2021

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tom 37

151-163

EN

This study investigated the phytochemical composition and antimicrobial activities of ethanol and methanol leaf extracts of Lantana camara Linn against some clinical pathogens. The ethanol and methanol extracts were obtained by soaking each of the powdered leaf in each solvent. The soaked powdered leaf was allowed to stand for four days at room temperature and later filtered using Whatman filter paper. The filtrate was further concentrated using rotary evaporator and then freeze-dried. The minimum inhibitory concentration (MIC) of the ethanol and methanol leaf extracts was carried out using agar well diffusion method. The phytochemical analysis was done using standard techniques. Data were analysed using Analysis of Variance (ANOVA) to test for significance. Means were separated using Duncan’s Multiple Range Test (DMRT). The results of the antimicrobial activity revealed that V. cholerae was the most susceptible while E. coli was the most resistant to plant extracts. The phytochemicals present in the plant leaf had antimicrobial properties and may serve as a good substitute for resistant human pathogens.