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Article ; Online: Sulfolane as a novel stationary phase for analytical separations by gas chromatography.

Darko, Ernest / Thurbide, Kevin B

2021 Volume 1189, Page(s) 339254

Abstract: Sulfolane is explored as a novel stationary phase for use in analytical separations by capillary column gas chromatography with flame ionization detection (GC-FID). Stainless steel capillaries were found to provide a good substrate for coating and ... ...

Abstract	Sulfolane is explored as a novel stationary phase for use in analytical separations by capillary column gas chromatography with flame ionization detection (GC-FID). Stainless steel capillaries were found to provide a good substrate for coating and retaining a sulfolane phase, whereas fused silica tubing did not perform well for this. In general, the phase was found to be stable for several hours of use when using elevated carrier gas pressures (90 psi) and a small restriction (25 μm I.D. tubing) at the outlet. This normally provided good performance at temperatures up to about 200 °C with very little background interference in the FID. Given its separation properties, a short 2 m × 100 μm I.D. column was found to be preferable for most separations in this study. Measurements indicated the coating procedure yielded a sulfolane film near 4 μm thick on this column, which produced 4400 plates for benzene with a sample capacity near 30 μg. The sulfolane phase yielded good retention and peak shape for many analytes including alkanes, aromatics, alcohols, bases, sulfides, phosphites, thiols, and others. Compared to longer conventional GC columns, the relatively short sulfolane column was found to offer improved selectivity in the separation of unsaturated, aromatic, and alkane test analytes. As such the method was successfully applied to the analysis of aromatics in gasoline headspace. Results suggest that sulfolane could be a potentially useful stationary phase to further explore in GC separations.
MeSH term(s)	Alkanes ; Chromatography, Gas ; Flame Ionization ; Thiophenes
Chemical Substances	Alkanes ; Thiophenes ; sulfolane (Y5L06AH4G5)
Language	English
Publishing date	2021-11-06
Publishing country	Netherlands
Document type	Journal Article
ZDB-ID	1483436-4
ISSN	1873-4324 ; 0003-2670
ISSN (online)	1873-4324
ISSN	0003-2670
DOI	10.1016/j.aca.2021.339254
Database	MEDical Literature Analysis and Retrieval System OnLINE

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Article: Effects of High Voltage Electrical Discharge (HVED) on Endogenous Hormone and Polyphenol Profile in Wheat.

Marček, Tihana / Hamow, Kamirán Áron / Janda, Tibor / Darko, Eva

Plants (Basel, Switzerland)

2023 Volume 12, Issue 6

Abstract: High voltage electrical discharge (HVED) is an eco-friendly low-cost method based on the creation of plasma-activated water (PAW) through the release of electrical discharge in water which results in the formation of reactive particles. Recent studies ... ...

Abstract	High voltage electrical discharge (HVED) is an eco-friendly low-cost method based on the creation of plasma-activated water (PAW) through the release of electrical discharge in water which results in the formation of reactive particles. Recent studies have reported that such novel plasma technologies promote germination and growth but their hormonal and metabolic background is still not known. In the present work, the HVED-induced hormonal and metabolic changes were studied during the germination of wheat seedlings. Hormonal changes including abscisic acid (ABA), gibberellic acids (GAs), indol acetic acid (IAA) and jasmonic acid (JA) and the polyphenol responses were detected in the early (2nd day) and late (5th day) germination phases of wheat as well as their redistribution in shoot and root. HVED treatment significantly stimulated germination and growth both in the shoot and root. The root early response to HVED involved the upregulation of ABA and increased phaseic and ferulic acid content, while the active form of gibberellic acid (GA1) was downregulated. In the later phase (5th day of germination), HVED had a stimulatory effect on the production of benzoic and salicylic acid. The shoot showed a different response: HVED induced the synthesis of JA_Le_Ile, an active form of JA, and provoked the biosynthesis of cinnamic,
Language	English
Publishing date	2023-03-08
Publishing country	Switzerland
Document type	Journal Article
ZDB-ID	2704341-1
ISSN	2223-7747
ISSN	2223-7747
DOI	10.3390/plants12061235
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Article ; Online: Changes in the light environment: Short-term responses of photosynthesis and metabolism in spinach.

Darko, Eva / Gondor, Kinga O / Kovács, Viktória / Janda, Tibor

Physiologia plantarum

2023 Volume 175, Issue 5, Page(s) e13996

Abstract: Modification in the light environment can induce several changes even within a short time. In this article, light intensity and spectrum-dependent changes in photosynthetic and metabolic processes were investigated in spinach leaves. Short-term exposure ... ...

Abstract	Modification in the light environment can induce several changes even within a short time. In this article, light intensity and spectrum-dependent changes in photosynthetic and metabolic processes were investigated in spinach leaves. Short-term exposure of the youngest fully developed leaves provided an elevated CO
MeSH term(s)	Spinacia oleracea/metabolism ; Carbon Dioxide/metabolism ; Photosynthesis ; Light ; Electron Transport ; Plant Leaves/metabolism
Chemical Substances	Carbon Dioxide (142M471B3J)
Language	English
Publishing date	2023-08-03
Publishing country	Denmark
Document type	Journal Article
ZDB-ID	2020837-6
ISSN	1399-3054 ; 0031-9317
ISSN (online)	1399-3054
ISSN	0031-9317
DOI	10.1111/ppl.13996
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Article ; Online: Active control of selectivity in organic acid analysis by gas chromatography.

Darko, Ernest / Thurbide, Kevin B

Analytica chimica acta

2020 Volume 1106, Page(s) 216–223

Abstract: A new method that allows organic acid selectivity to be dynamically controlled during gas chromatography (GC) is presented. It employs dual in-series stainless steel columns, each coated with a pH-adjusted water stationary phase. The first is a 2 m ... ...

Abstract	A new method that allows organic acid selectivity to be dynamically controlled during gas chromatography (GC) is presented. It employs dual in-series stainless steel columns, each coated with a pH-adjusted water stationary phase. The first is a 2 m column coated with a pH 11.4 phase that is connected to a second 11 m column coated with a pH 2.2 phase. In this arrangement, organic acids within sample mixtures are trapped on the first column, while the remaining non-ionizable components continue to separate and elute in the system. Later, by injecting a volatile formic acid solution, the trapped acids are released in-situ to the second column for separation and analysis as desired. The method provides good reproducibility with analyte retention times in consecutive trials yielding an average RSD of 1.9%. Further, depending on column temperature, analytes can be readily retained for periods investigated up to about 30 min without significant deterioration in peak shape. This feature provides considerable control over analyte selectivity and resolution compared to conventional separations. Further, by adding a third conventional GC column in-series, both typical hydrocarbon and enhanced organic acid separations are made possible. The method is applied to the analysis of complex mixtures and matrix interference is found to be significantly minimized. Results indicate that this approach offers beneficial advantages for the selective GC analysis of such acidic analytes.
Language	English
Publishing date	2020-01-28
Publishing country	Netherlands
Document type	Journal Article
ZDB-ID	1483436-4
ISSN	1873-4324 ; 0003-2670
ISSN (online)	1873-4324
ISSN	0003-2670
DOI	10.1016/j.aca.2020.01.059
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Article ; Online: Changes in the light environment: Short‐term responses of photosynthesis and metabolism in spinach

Darko, Eva / Gondor, Kinga O. / Kovács, Viktória / Janda, Tibor

Physiologia Plantarum. 2023 , v. 175, no. 5 p.e13996-

2023

Abstract: Modification in the light environment can induce several changes even within a short time. In this article, light intensity and spectrum‐dependent changes in photosynthetic and metabolic processes were investigated in spinach leaves. Short‐term exposure ... ...

Abstract	Modification in the light environment can induce several changes even within a short time. In this article, light intensity and spectrum‐dependent changes in photosynthetic and metabolic processes were investigated in spinach leaves. Short‐term exposure of the youngest fully developed leaves provided an elevated CO₂ assimilation capacity under red light compared with blue or white light, although the electron transport rate was lower. The stomatal opening was mainly stimulated by blue light. These spectrum‐induced changes also depended on light intensity. When white light was used to activate the photosynthesis, the white light showed a similar light response to blue light regarding the electron transport processes and red light in terms of stomatal opening. In contrast, concerning CO₂ assimilation characteristics, the white light resembled blue light at low and red light at high light intensities. These results indicate that the photosynthetic processes strongly interact with the light intensity and spectral composition. Furthermore, changes in spectral composition modified the primary metabolic processes as well. Red light induced the sugar accumulation, while more organic acids that belong to the respiration pathway were produced under blue and white lights. These changes occurred even within a short (30 min) time frame. These results also draw attention to the importance of the light environment used during the measurements of the photosynthetic activity of plants and/or sample collections.
Keywords	acute exposure ; blue light ; carbon dioxide ; electron transfer ; light intensity ; photosynthesis ; red light ; spinach ; sugars ; white light
Language	English
Dates of publication	2023-09
Publishing place	Blackwell Publishing Ltd
Document type	Article ; Online
Note	JOURNAL ARTICLE
ZDB-ID	2020837-6
ISSN	1399-3054 ; 0031-9317
ISSN (online)	1399-3054
ISSN	0031-9317
DOI	10.1111/ppl.13996
Database	NAL-Catalogue (AGRICOLA)

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Article ; Online: Crosstalk between Light- and Temperature-Mediated Processes under Cold and Heat Stress Conditions in Plants.

Janda, Tibor / Prerostová, Sylva / Vanková, Radomíra / Darkó, Éva

International journal of molecular sciences

2021 Volume 22, Issue 16

Abstract: Extreme temperatures are among the most important stressors limiting plant growth and development. Results indicate that light substantially influences the acclimation processes to both low and high temperatures, and it may affect the level of stress ... ...

Abstract	Extreme temperatures are among the most important stressors limiting plant growth and development. Results indicate that light substantially influences the acclimation processes to both low and high temperatures, and it may affect the level of stress injury. The interaction between light and temperature in the regulation of stress acclimation mechanisms is complex, and both light intensity and spectral composition play an important role. Higher light intensities may lead to overexcitation of the photosynthetic electron transport chain; while different wavelengths may act through different photoreceptors. These may induce various stress signalling processes, leading to regulation of stomatal movement, antioxidant and osmoregulation capacities, hormonal actions, and other stress-related pathways. In recent years, we have significantly expanded our knowledge in both light and temperature sensing and signalling. The present review provides a synthesis of results for understanding how light influences the acclimation of plants to extreme low or high temperatures, including the sensing mechanisms and molecular crosstalk processes.
MeSH term(s)	Cold-Shock Response ; Heat-Shock Response ; Photosynthesis ; Plants/metabolism ; Plants/radiation effects ; Signal Transduction ; Sunlight
Language	English
Publishing date	2021-08-10
Publishing country	Switzerland
Document type	Journal Article ; Review
ZDB-ID	2019364-6
ISSN	1422-0067 ; 1422-0067 ; 1661-6596
ISSN (online)	1422-0067
ISSN	1422-0067 ; 1661-6596
DOI	10.3390/ijms22168602
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Article: Nutritional quality of snacks and beverages sold through vending machines in a large Hispanic-serving urban college campus in the United States: A cross-sectional study.

Samuel, Lalitha / Odoom-Darko, Ellen / Del Rosario, Suilan Jon / Blake, Charmaine

Journal of public health research

2023 Volume 12, Issue 2, Page(s) 22799036231170842

Abstract: Students from nutritionally-vulnerable neighborhoods face dietary challenges through built environment of college vending machines. In this cross-sectional study, snacks and beverages sold in vending machines for a 4-week period in a Bronx-based Hispanic- ...

Abstract	Students from nutritionally-vulnerable neighborhoods face dietary challenges through built environment of college vending machines. In this cross-sectional study, snacks and beverages sold in vending machines for a 4-week period in a Bronx-based Hispanic-serving college were recorded. Nutritional information was recorded from nutrition labels. Proportion of low- and high-sodium foods, "smart snacks" with a limit of 200 kcal and 200 mg of sodium, and foods with added sugar were recorded. Snacks had significantly higher calories and sodium per serving (227 kcal, 208 mg) than beverages (132 kcal, 90 mg) (
Language	English
Publishing date	2023-05-04
Publishing country	United States
Document type	Journal Article
ISSN	2279-9028
ISSN	2279-9028
DOI	10.1177/22799036231170842
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Article ; Online: Dynamic Control of Gas Chromatographic Selectivity during the Analysis of Organic Bases.

Darko, Ernest / Thurbide, Kevin B

Analytical chemistry

2019 Volume 91, Issue 10, Page(s) 6682–6688

Abstract: A novel method for controlling selectivity during the gas chromatographic (GC) analysis of organic bases is presented. The technique employs tandem stainless steel capillary columns, each coated with a pH adjusted water stationary phase. The first is a 0. ...

Abstract	A novel method for controlling selectivity during the gas chromatographic (GC) analysis of organic bases is presented. The technique employs tandem stainless steel capillary columns, each coated with a pH adjusted water stationary phase. The first is a 0.5 m trap column coated with a pH 2.2 phase, while the second is an 11 m analytical column coated with a pH 11.4 phase. The first column traps basic analytes from injected samples, while the remaining components continue to elute and separate. Then, upon injection of a volatile aqueous ammonia solution, the basic analytes are released as desired to the analytical column where they are separated and analyzed. Separations are quite reproducible and demonstrate an average RSD of 1.2% for analyte retention times in consecutive trials. Using this approach, the retention of such analytes can be readily controlled and they can be held in the system for periods of up to 1 h without significant erosion of peak shape. As such, it can provide considerable control over analyte selectivity and resolution compared to conventional separations. Further, by employing a third conventional GC column to the series, both traditional hydrocarbon and enhanced organic base separations can be performed. The method is applied to the analysis of complex mixtures, such as gasoline, and much less matrix interference is observed as a result. The findings indicate that this approach could be a useful alternative for analyzing such samples.
Language	English
Publishing date	2019-05-07
Publishing country	United States
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	1508-8
ISSN	1520-6882 ; 0003-2700
ISSN (online)	1520-6882
ISSN	0003-2700
DOI	10.1021/acs.analchem.9b00703
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Article: Medical Students' Corner: Barriers to Communication During the COVID-19 Pandemic.

Ogunbiyi, M Olabisi / Obiri-Darko, Emma

JMIR medical education

2020 Volume 6, Issue 2, Page(s) e24989

Abstract: The COVID-19 pandemic has inspired us, as medical students, to reflect upon the communication training we have received in medical school and the obstacles we have faced in the clinic due to COVID-19. We hold the view that our communication training is ... ...

Abstract	The COVID-19 pandemic has inspired us, as medical students, to reflect upon the communication training we have received in medical school and the obstacles we have faced in the clinic due to COVID-19. We hold the view that our communication training is inadequate; this view is driven by our limited exposure to patients, a situation that is currently being exacerbated by the pandemic. The medical curriculum must be inclusive of all groups and take into account the new challenges arising during the COVID-19 pandemic.
Keywords	covid19
Language	English
Publishing date	2020-11-27
Publishing country	Canada
Document type	Journal Article
ISSN	2369-3762
ISSN	2369-3762
DOI	10.2196/24989
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Article ; Online: STUDIES OF RADON LEVELS, RADIUM CONCENTRATION, AND ESTIMATED EFFECTIVE DOSE IN DWELLINGS AND SOILS IN GOLD MINING TOWNS IN ABIREM OF EASTERN REGION OF GHANA.

Otoo, F / Arhin, I / Darko, E O

Radiation protection dosimetry

2020 Volume 191, Issue 3, Page(s) 296–309

Abstract: Studies have been carried in 126 dwellings for indoor radon levels and 43 soil samples for radium and radon exhalation rate of Abirem communities in Eastern region of Ghana. The measurements were done using CR-39 and HPGe techniques. Indoor radon and ... ...

Abstract	Studies have been carried in 126 dwellings for indoor radon levels and 43 soil samples for radium and radon exhalation rate of Abirem communities in Eastern region of Ghana. The measurements were done using CR-39 and HPGe techniques. Indoor radon and mean concentration ranged from 23.8 to 125.7 Bq/m3, 54.7 ± 23.7 Bq/m3. Bedroom, kitchen, and sitting varied from 30.8 to 125.7 Bq/m3, 23.8-63.9 Bq/m3 and 23.8 to 58.4 Bq/m3. Strong and weak Pearson correlation were found between radium and radon in soil, radium and indoor radon concentration. Radium concentration and mean were found to be varied from 19.5 to 38.9 Bq/kg, 29.0 ± 16.0 Bq/kg. The radon exhalation rate and mean in soil were also found to be varied from 21.3 to 112.1 μBq/m2h, 65.1 ± 27.6 μBq/m2h. Indoor radon values and radium concentration in dwellings and soil recorded 8% and 38%, respectively, more than action proposed by WHO and UNSCEAR 2000. The estimated annual effective doses and cancer risk were less than the average values recommended by UNSCEAR and ICRP.
MeSH term(s)	Air Pollution, Indoor/analysis ; Cities ; Ghana ; Housing ; Mining ; Radiation Monitoring ; Radium/analysis ; Radon/analysis ; Soil
Chemical Substances	Soil ; Radon (Q74S4N8N1G) ; Radium (W90AYD6R3Q)
Language	English
Publishing date	2020-09-25
Publishing country	England
Document type	Journal Article
ZDB-ID	225912-6
ISSN	1742-3406 ; 0144-8420
ISSN (online)	1742-3406
ISSN	0144-8420
DOI	10.1093/rpd/ncaa129
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