Chau Dinh - Academia.edu (original) (raw)

Papers by Chau Dinh

Minerals

Activity concentration of 210Pb in black powder and gamma radiation dose rate related to natural ... more Activity concentration of 210Pb in black powder and gamma radiation dose rate related to natural gas transportation were discussed. As part of the research, the content of radiolead (210Pb) in black powder, spent filter containers, radon (222Rn) activity concentration in natural gas and gamma radiation dose were measured around selected points of natural gas transportation infrastructure in Poland. The content of some heavy metals was also analyzed. The average concentrations of 222Rn and 210Pb ranged from 30 to 1400 Bq/m3 and from around 450 to 16,000 Bq/kg, respectively. The external exposure to gamma radiation was low; the gamma radiation dose rate was at the level of background radiation or slightly exceeded it. The research demonstrated that the content of 210Pb in black powder is strongly related to radon concentration in natural gas, the volumetric flow rate of the transported natural gas and solid fraction content. Some black powder samples should be classified based on 210P...

Acoustics, 2021

In order to determine the optimal parameters when using an ultrasonic probe to measure cavern geo... more In order to determine the optimal parameters when using an ultrasonic probe to measure cavern geometry when a metal borehole pipe is present, an investigation was firstly carried out on influence of a vertical metal plates with a thickness from 1 mm to 15 mm immersed in water on transmitted and reflected ultrasonic waves. The results obtained will be used as an indicator for the measurement of underground geometry in which the ultrasonic probe is placed inside a metal pipe lining a borehole. These studies were performed both by experiment and computer simulation. The results show that the wavelength of the incident ultrasonic signals should be equal to half the thickness of the metal plate or an integer times smaller than this thickness. When the thickness of the barrier is unknown, an ultrasonic signal with linear frequency modulation (LFM) should be used. Due to the reverberation of the ultrasonic waves inside the pipe for caverns filled with water, the distance from the transduce...

Arem vocabulary, from word item 2687 to word item 2896, EFEO-CNRS-SOAS lexicon [from n° 425.3 to ... more Arem vocabulary, from word item 2687 to word item 2896, EFEO-CNRS-SOAS lexicon [from n° 425.3 to 471a following Ferlus's numbering]

Etude sur la semisynsynthese de quelques nouveaux derives solubles dans l'eau de la dihydroar... more Etude sur la semisynsynthese de quelques nouveaux derives solubles dans l'eau de la dihydroartemisinine, On a synthetise une serie de derives de la dihydroartemisinine contenant un groupement carboxylique de la liaison d'ester au C10. La synthese a ete executee par traitement de la dihydroartemisinine avec des anhydrides dicarboxyliques appropries en presence de la mixture de triethylamine et de 4 - dimethylamino pyridine dans du chloroforme anhydre employee comme catalyseur de l'acylation, et de la solution d'alcools appropries dans l'ether ethylique en presence du BF 3 (C 2 H 5 ) 2 O a temperature ambiante.

European Journal of Medicinal Chemistry, 2020

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Journal of Radioanalytical and Nuclear Chemistry, 2020

The research was focused on the level and distribution of 90Sr in various parts of the terrestria... more The research was focused on the level and distribution of 90Sr in various parts of the terrestrial environment of Spitsbergen. The mean activity concentrations were noted lower in peats and soils than in cryoconite. Analysis of vertical variation of 90Sr for soils and peats as well as isotopic ratios of 137Cs/90Sr and 239+240Pu/90Sr for cryoconite clearly showed substantial migration or depletion of the considered radionuclide. Due to the large dispersion of isotopic signatures, the 90Sr provenance was difficult to identify in the examined region. However, observed high mobility of the 90Sr might indicate the global fallout origin.

Energies, 2021

A natural radioactivity in thermal water was investigated based on 19 selected thermal waters fro... more A natural radioactivity in thermal water was investigated based on 19 selected thermal waters from Poland. The analysed results show that the radionuclides’ concentrations in the study waters vary over a wide range. The temperature of the waters varies from above 20 °C to above 80 °C. The waters are characterised by different mineralisation, chemical compositions, and belong to different hydrochemical types. There is a good correlation between the water temperature and the depths of the aquifer formations occurrence, suggesting the thermal energy originates from the thermal geogradient. The concentration of radium is well correlated with the water mineralisation. The ratio of radium activity (226Ra/228Ra) in groundwater relates not only the ratio of uranium activity to that of thorium (238U/232Th) in aquifer formation, but also depends on the physical and chemical water properties. Based on the concentration of radon and its transport model, the radiation exposures due to inhalation...

Biomolecules, 2020

Modulation of major histocompatibility complex (MHC) expression using drugs has been proposed to ... more Modulation of major histocompatibility complex (MHC) expression using drugs has been proposed to control immunity. Phytochemical investigations on Garcinia species have allowed the isolation of bioactive compounds such as polycyclic polyprenylated acylphloroglucinols (PPAPs). PPAPs such as guttiferone J (1), display anti-inflammatory and immunoregulatory activities while garcinol (4) is a histone acetyltransferases (HAT) p300 inhibitor. This study reports on the isolation, identification and biological characterization of two other PPAPs, i.e., xanthochymol (2) and guttiferone F (3) from Garcinia bancana, sharing structural analogy with guttiferone J (1) and garcinol (4). We show that PPAPs 1–4 efficiently downregulated the expression of several MHC molecules (HLA-class I, -class II, MICA/B and HLA-E) at the surface of human primary endothelial cells upon inflammation. Mechanistically, PPAPs 1–4 reduce MHC proteins by decreasing the expression and phosphorylation of the transcriptio...

ACS Omega, 2020

Concrete structures in the sewer are corroded by sulfuric acid solution resulted from the actions... more Concrete structures in the sewer are corroded by sulfuric acid solution resulted from the actions of microorganisms in a sewer environment. Many reports pointed out that it can shorten the service life of concrete sewer networks from 10 to 50 years. Isolation of sulfuric acid solution from the surface of the sewerage concrete structures by using a polymer lining is effective corrosion protection. This study presents the preparation of a silica−epoxy nanocomposite material used for this lining purpose. Diffusion behavior, the cohesion of the lining on the concrete surface under the severer conditions, was investigated. Dispersion and distribution of the nanoparticles in the epoxy matrix confirmed by scanning electron microscopy (SEM) and X-ray diffraction analysis contribute to the enhancement of the lining's barrier properties to water and to H 2 SO 4 acid solution at different temperatures. An improvement of cohesion between the concrete and the nanocomposite lining was found. The nanocomposite lining remained cohesive on a concrete substrate almost two times longer than the neat lining when they were exposed to the 10.0 wt % H 2 SO 4 acid solution at both 40 and 60°C. The energy-dispersive system combined SEM analysis results of the pulled-off linings confirmed that the corrosion of the concrete interfaces is because of H 2 SO 4 acid. It contributes to the adhesion loss of the lining. Thus, loaded nanosilica particles into epoxy enhance barrier properties, bond strength, and longevity of the service life of the sewerage concrete structure.

Journal of Nanomaterials, 2020

This work presents the performance of a SiO2-epoxy nanocomposite lining for the anticorrosion of ... more This work presents the performance of a SiO2-epoxy nanocomposite lining for the anticorrosion of the concrete structures in sewer networks. Nanocomposite lining on the concrete substrate surface of the 15 phr (part per hundred epoxy resin) amine-cured epoxy polymer containing 3.0 phr of nano-SiO2 was prepared by intercalating epoxy into the SiO2 via direct mixing process. The silica exfoliation was monitored by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The barrier feature of epoxy the base nanocomposite against water and sulfuric acid solution was evaluated. The results showed that the nanocomposite lining was of a great barrier against these corrosive environments due to the intercalation and exfoliation caused by the dispersion of the SiO2 nanoparticles into the epoxy matrix. The rate of the H2SO4 into the nanocomposite lining was also investigated by measurement of the depth of the sulfur element penetrated layer using the coupled Scanning Electron Micro...

Acta Geophysica, 2019

Effectiveness of transient electromagnetic method (TEM) used for the localization of Pb-Zn ore bo... more Effectiveness of transient electromagnetic method (TEM) used for the localization of Pb-Zn ore bodies at the Cho Don deposit, province Bac Can, North Vietnam is appraised based on the modelling processes results. Conductive Pb-Zn ore bodies hosted in high-resistive limestone are in good conditions for the application of the TEM. The modelling process relays on the calculation of the voltage decay in time domain formed from the induced magnetic field diffusing into the study medium, when a pulse current with a given frequency is flowing in a transmitting loop coil. The model results show that the power current of 1 A transmitted from the coils with 100 or 400 m of size is effective for localization of the Zn-Pb ore bodies. However, the resolution and penetration depth of the TEM with a coil of L = 100 m is better and shorter in comparison with those in the case using the coil L = 400 m.

Acta Geophysica, 2019

The Ruczaj district in Kraków is the potential building area of high flat blocks for inhabitants.... more The Ruczaj district in Kraków is the potential building area of high flat blocks for inhabitants. This area is built of the gypsum basement covered by the soil and impermeable clay beds with several meters of thickness. The flat blocks must be set on the textured gypsum layer. In the result of the rainfall and static pressure of the blocks, the water with SO 4 2− increases up to the groundwater level, become the great threat for the flat blocks. The water creates specific hydrogeological conditions occurring in the zone of the building's foundations. To eliminate the mentioned threat, we should determine precisely the thickness of the soil and impermeable clay as well as the depth of the gypsum basement. Based on the electromagnetic parameters of the geological formations, the Ground Conductivity Meter and DC resistivity methods were used to solve the mentioned problems.

Research Journal of Environmental and Earth Sciences, 2014

This paper presents the study of natural radioactivity in Tanzania Portland cements and their raw... more This paper presents the study of natural radioactivity in Tanzania Portland cements and their raw materials. Samples collected as raw materials were pozzolan, sandstone, limestone, clay, gypsum and cement as finished products. The natural radioactivity due to the presence of radium 226 Ra, thorium 232 Th and potassium 40 K were measured by means of gamma spectrometer coupled with HPGe detector. The mean measured activity concentrations of 226 Ra, 232 Th and 40 K in the raw materials range from 2.6 to 93.2, 1.3 to 172.8 and 6.3 to 997 Bq/kg, respectively with higher activity concentrations in pozzolan and lower in gypsum. Activity concentrations of natural radionuclides in raw materials (excluding some materials from Songwe deposits in Mbeya region) are comparative with the worldwide average concentrations of these radionuclides in soil. The average activity concentration of 226 Ra, 232 Th and 40 K in the cements are 46, 28 and 228 Bq/kg, respectively. The calculated values of radiological indices are below 60% of the upper recommended values for building materials. The average annual effective dose to an occupant from use of these materials equals to 0.45 mSv. Average activity concentrations of the mentioned radionuclides in Tanzania cements are in the middle of the variability interval of the national averages.

Nature Communications, 2018

Systemic vitamin E metabolites have been proposed as signaling molecules, but their physiological... more Systemic vitamin E metabolites have been proposed as signaling molecules, but their physiological role is unknown. Here we show, by library screening of potential human vitamin E metabolites, that long-chain ω-carboxylates are potent allosteric inhibitors of 5-lipoxygenase, a key enzyme in the biosynthesis of chemoattractant and vasoactive leukotrienes. 13-((2R)-6-hydroxy-2,5,7,8-tetramethylchroman-2-yl)-2,6,10-trimethyltridecanoic acid (α-T-13′-COOH) can be synthesized from α-tocopherol in a human liver-on-chip, and is detected in human and mouse plasma at concentrations (8–49 nM) that inhibit 5-lipoxygenase in human leukocytes. α-T-13′-COOH accumulates in immune cells and inflamed murine exudates, selectively inhibits the biosynthesis of 5-lipoxygenase-derived lipid mediators in vitro and in vivo, and efficiently suppresses inflammation and bronchial hyper-reactivity in mouse models of peritonitis and asthma. Together, our data suggest that the immune regulatory and anti-inflammat...

Journal of Radioanalytical and Nuclear Chemistry, 2018

The 238 U, 226 Ra and 232 Th contents of six samples from the Mandena black sand placer deposit w... more The 238 U, 226 Ra and 232 Th contents of six samples from the Mandena black sand placer deposit were determined by gammaray spectrometry and varied from 2280 to 4600 Bq/kg, 1530 to 2900 Bq/kg and 11,600 to 25,400 Bq/kg, respectively. The activity concentration of 232 Th is significantly higher than 238 U and there is no equilibrium between 238 U and 226 Ra. Due to the gamma interferences at the line 1461 keV and very high 228 Ac activity, the 40 K was calculated through potassium analyzed using ICP-AES and varied from 1 to 19 Bq/kg. The calculated gamma absorbed dose rate ranged from 7700 to 16,700 nGy/h.

Journal of environmental radioactivity, 2017

In the present study, the K-40, U-238, Ra-226, Pb-210, Ra-228 and Th-228 activity concentrations ... more In the present study, the K-40, U-238, Ra-226, Pb-210, Ra-228 and Th-228 activity concentrations were measured in 64 samples of wastes generated from shale gas exploration in North-Eastern Poland. The measured samples consist of drill cuttings, solid phase of waste drilling muds, fracking fluids, return fracking fluids and waste proppants. The measured activity concentrations in solid samples vary in a wide range from 116 to around 1100 Bq/kg for K-40, from 14 to 393 Bq/kg for U-238, from 15 to 415 Bq/kg for Ra-226, from 12 to 391 Bq/kg for Pb-210, from a few Bq/kg to 516 Bq/kg for Ra-228 and from a few Bq/kg to 515 Bq/kg for Th-228. Excluding the waste proppants, the measured activity concentrations in solid samples oscillate around their worldwide average values in soil. In the case of the waste proppants, the activity concentrations of radionuclides from uranium and thorium decay series are significantly elevated and equal to several hundreds of Bq/kg but it is connected with the...

Uranium - Past and Future Challenges, 2014

This paper presents the assessment of radiation exposure due to inhalation of Rn-222 and its prog... more This paper presents the assessment of radiation exposure due to inhalation of Rn-222 and its progeny for workers and clients of selected thermal water spas. The evaluation of the radon risk is based on the activity concentration of Rn-222 in the investigated thermal waters. For this purpose, a radon transfer coefficient which describes a fraction of radon transferred from swimming-pool water to the indoor swimming-pool air was calculated. The evaluated annual effective dos-es for the model clients and workers range in the intervals of 0.40 μSv to 194 μSv and 0.022 mSv to 10.8 mSv, respectively.

Microelectronics Reliability, 2014

A simple fabrication scheme of using silver-filled conductive tape to form flexible single crysta... more A simple fabrication scheme of using silver-filled conductive tape to form flexible single crystalline Si-Pd Schottky diodes on a polymer substrate has been studied and reported previously. In this investigation, we studied the long term thermal stability of these flexible diodes on polymer annealed at 80°C in open air for 1 year. The I-V characteristics of the diodes were measured periodically. We found that the barrier height of the Si-Pd diodes remained relatively unchanged at 0.795 eV ± 0.003 with an n-factor of 1.03 ± 0.03, and a series resistance of $110 X for diodes with a 950 lm diameter, which are almost identical to the values before annealing. The integrated structure stayed flexible to a similar curvature after 1 year. The stability of silver-filled conductive tape was investigated separately over the same period of time and under the same conditions. The resistance of two conductive tapes was found to quickly decrease from high initial values to significantly lower values, and remained constant over the course of the investigation. Based on these results, we conclude that this simple bonding technique of using conductive tape to fabricate flexible devices can be of useful value in practical applications.

Minerals

Activity concentration of 210Pb in black powder and gamma radiation dose rate related to natural ... more Activity concentration of 210Pb in black powder and gamma radiation dose rate related to natural gas transportation were discussed. As part of the research, the content of radiolead (210Pb) in black powder, spent filter containers, radon (222Rn) activity concentration in natural gas and gamma radiation dose were measured around selected points of natural gas transportation infrastructure in Poland. The content of some heavy metals was also analyzed. The average concentrations of 222Rn and 210Pb ranged from 30 to 1400 Bq/m3 and from around 450 to 16,000 Bq/kg, respectively. The external exposure to gamma radiation was low; the gamma radiation dose rate was at the level of background radiation or slightly exceeded it. The research demonstrated that the content of 210Pb in black powder is strongly related to radon concentration in natural gas, the volumetric flow rate of the transported natural gas and solid fraction content. Some black powder samples should be classified based on 210P...

Acoustics, 2021

In order to determine the optimal parameters when using an ultrasonic probe to measure cavern geo... more In order to determine the optimal parameters when using an ultrasonic probe to measure cavern geometry when a metal borehole pipe is present, an investigation was firstly carried out on influence of a vertical metal plates with a thickness from 1 mm to 15 mm immersed in water on transmitted and reflected ultrasonic waves. The results obtained will be used as an indicator for the measurement of underground geometry in which the ultrasonic probe is placed inside a metal pipe lining a borehole. These studies were performed both by experiment and computer simulation. The results show that the wavelength of the incident ultrasonic signals should be equal to half the thickness of the metal plate or an integer times smaller than this thickness. When the thickness of the barrier is unknown, an ultrasonic signal with linear frequency modulation (LFM) should be used. Due to the reverberation of the ultrasonic waves inside the pipe for caverns filled with water, the distance from the transduce...

Arem vocabulary, from word item 2687 to word item 2896, EFEO-CNRS-SOAS lexicon [from n° 425.3 to ... more Arem vocabulary, from word item 2687 to word item 2896, EFEO-CNRS-SOAS lexicon [from n° 425.3 to 471a following Ferlus's numbering]

Etude sur la semisynsynthese de quelques nouveaux derives solubles dans l'eau de la dihydroar... more Etude sur la semisynsynthese de quelques nouveaux derives solubles dans l'eau de la dihydroartemisinine, On a synthetise une serie de derives de la dihydroartemisinine contenant un groupement carboxylique de la liaison d'ester au C10. La synthese a ete executee par traitement de la dihydroartemisinine avec des anhydrides dicarboxyliques appropries en presence de la mixture de triethylamine et de 4 - dimethylamino pyridine dans du chloroforme anhydre employee comme catalyseur de l'acylation, et de la solution d'alcools appropries dans l'ether ethylique en presence du BF 3 (C 2 H 5 ) 2 O a temperature ambiante.

European Journal of Medicinal Chemistry, 2020

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Journal of Radioanalytical and Nuclear Chemistry, 2020

The research was focused on the level and distribution of 90Sr in various parts of the terrestria... more The research was focused on the level and distribution of 90Sr in various parts of the terrestrial environment of Spitsbergen. The mean activity concentrations were noted lower in peats and soils than in cryoconite. Analysis of vertical variation of 90Sr for soils and peats as well as isotopic ratios of 137Cs/90Sr and 239+240Pu/90Sr for cryoconite clearly showed substantial migration or depletion of the considered radionuclide. Due to the large dispersion of isotopic signatures, the 90Sr provenance was difficult to identify in the examined region. However, observed high mobility of the 90Sr might indicate the global fallout origin.

Energies, 2021

A natural radioactivity in thermal water was investigated based on 19 selected thermal waters fro... more A natural radioactivity in thermal water was investigated based on 19 selected thermal waters from Poland. The analysed results show that the radionuclides’ concentrations in the study waters vary over a wide range. The temperature of the waters varies from above 20 °C to above 80 °C. The waters are characterised by different mineralisation, chemical compositions, and belong to different hydrochemical types. There is a good correlation between the water temperature and the depths of the aquifer formations occurrence, suggesting the thermal energy originates from the thermal geogradient. The concentration of radium is well correlated with the water mineralisation. The ratio of radium activity (226Ra/228Ra) in groundwater relates not only the ratio of uranium activity to that of thorium (238U/232Th) in aquifer formation, but also depends on the physical and chemical water properties. Based on the concentration of radon and its transport model, the radiation exposures due to inhalation...

Biomolecules, 2020

Modulation of major histocompatibility complex (MHC) expression using drugs has been proposed to ... more Modulation of major histocompatibility complex (MHC) expression using drugs has been proposed to control immunity. Phytochemical investigations on Garcinia species have allowed the isolation of bioactive compounds such as polycyclic polyprenylated acylphloroglucinols (PPAPs). PPAPs such as guttiferone J (1), display anti-inflammatory and immunoregulatory activities while garcinol (4) is a histone acetyltransferases (HAT) p300 inhibitor. This study reports on the isolation, identification and biological characterization of two other PPAPs, i.e., xanthochymol (2) and guttiferone F (3) from Garcinia bancana, sharing structural analogy with guttiferone J (1) and garcinol (4). We show that PPAPs 1–4 efficiently downregulated the expression of several MHC molecules (HLA-class I, -class II, MICA/B and HLA-E) at the surface of human primary endothelial cells upon inflammation. Mechanistically, PPAPs 1–4 reduce MHC proteins by decreasing the expression and phosphorylation of the transcriptio...

ACS Omega, 2020

Concrete structures in the sewer are corroded by sulfuric acid solution resulted from the actions... more Concrete structures in the sewer are corroded by sulfuric acid solution resulted from the actions of microorganisms in a sewer environment. Many reports pointed out that it can shorten the service life of concrete sewer networks from 10 to 50 years. Isolation of sulfuric acid solution from the surface of the sewerage concrete structures by using a polymer lining is effective corrosion protection. This study presents the preparation of a silica−epoxy nanocomposite material used for this lining purpose. Diffusion behavior, the cohesion of the lining on the concrete surface under the severer conditions, was investigated. Dispersion and distribution of the nanoparticles in the epoxy matrix confirmed by scanning electron microscopy (SEM) and X-ray diffraction analysis contribute to the enhancement of the lining's barrier properties to water and to H 2 SO 4 acid solution at different temperatures. An improvement of cohesion between the concrete and the nanocomposite lining was found. The nanocomposite lining remained cohesive on a concrete substrate almost two times longer than the neat lining when they were exposed to the 10.0 wt % H 2 SO 4 acid solution at both 40 and 60°C. The energy-dispersive system combined SEM analysis results of the pulled-off linings confirmed that the corrosion of the concrete interfaces is because of H 2 SO 4 acid. It contributes to the adhesion loss of the lining. Thus, loaded nanosilica particles into epoxy enhance barrier properties, bond strength, and longevity of the service life of the sewerage concrete structure.

Journal of Nanomaterials, 2020

This work presents the performance of a SiO2-epoxy nanocomposite lining for the anticorrosion of ... more This work presents the performance of a SiO2-epoxy nanocomposite lining for the anticorrosion of the concrete structures in sewer networks. Nanocomposite lining on the concrete substrate surface of the 15 phr (part per hundred epoxy resin) amine-cured epoxy polymer containing 3.0 phr of nano-SiO2 was prepared by intercalating epoxy into the SiO2 via direct mixing process. The silica exfoliation was monitored by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The barrier feature of epoxy the base nanocomposite against water and sulfuric acid solution was evaluated. The results showed that the nanocomposite lining was of a great barrier against these corrosive environments due to the intercalation and exfoliation caused by the dispersion of the SiO2 nanoparticles into the epoxy matrix. The rate of the H2SO4 into the nanocomposite lining was also investigated by measurement of the depth of the sulfur element penetrated layer using the coupled Scanning Electron Micro...

Acta Geophysica, 2019

Effectiveness of transient electromagnetic method (TEM) used for the localization of Pb-Zn ore bo... more Effectiveness of transient electromagnetic method (TEM) used for the localization of Pb-Zn ore bodies at the Cho Don deposit, province Bac Can, North Vietnam is appraised based on the modelling processes results. Conductive Pb-Zn ore bodies hosted in high-resistive limestone are in good conditions for the application of the TEM. The modelling process relays on the calculation of the voltage decay in time domain formed from the induced magnetic field diffusing into the study medium, when a pulse current with a given frequency is flowing in a transmitting loop coil. The model results show that the power current of 1 A transmitted from the coils with 100 or 400 m of size is effective for localization of the Zn-Pb ore bodies. However, the resolution and penetration depth of the TEM with a coil of L = 100 m is better and shorter in comparison with those in the case using the coil L = 400 m.

Acta Geophysica, 2019

The Ruczaj district in Kraków is the potential building area of high flat blocks for inhabitants.... more The Ruczaj district in Kraków is the potential building area of high flat blocks for inhabitants. This area is built of the gypsum basement covered by the soil and impermeable clay beds with several meters of thickness. The flat blocks must be set on the textured gypsum layer. In the result of the rainfall and static pressure of the blocks, the water with SO 4 2− increases up to the groundwater level, become the great threat for the flat blocks. The water creates specific hydrogeological conditions occurring in the zone of the building's foundations. To eliminate the mentioned threat, we should determine precisely the thickness of the soil and impermeable clay as well as the depth of the gypsum basement. Based on the electromagnetic parameters of the geological formations, the Ground Conductivity Meter and DC resistivity methods were used to solve the mentioned problems.

Research Journal of Environmental and Earth Sciences, 2014

This paper presents the study of natural radioactivity in Tanzania Portland cements and their raw... more This paper presents the study of natural radioactivity in Tanzania Portland cements and their raw materials. Samples collected as raw materials were pozzolan, sandstone, limestone, clay, gypsum and cement as finished products. The natural radioactivity due to the presence of radium 226 Ra, thorium 232 Th and potassium 40 K were measured by means of gamma spectrometer coupled with HPGe detector. The mean measured activity concentrations of 226 Ra, 232 Th and 40 K in the raw materials range from 2.6 to 93.2, 1.3 to 172.8 and 6.3 to 997 Bq/kg, respectively with higher activity concentrations in pozzolan and lower in gypsum. Activity concentrations of natural radionuclides in raw materials (excluding some materials from Songwe deposits in Mbeya region) are comparative with the worldwide average concentrations of these radionuclides in soil. The average activity concentration of 226 Ra, 232 Th and 40 K in the cements are 46, 28 and 228 Bq/kg, respectively. The calculated values of radiological indices are below 60% of the upper recommended values for building materials. The average annual effective dose to an occupant from use of these materials equals to 0.45 mSv. Average activity concentrations of the mentioned radionuclides in Tanzania cements are in the middle of the variability interval of the national averages.

Nature Communications, 2018

Systemic vitamin E metabolites have been proposed as signaling molecules, but their physiological... more Systemic vitamin E metabolites have been proposed as signaling molecules, but their physiological role is unknown. Here we show, by library screening of potential human vitamin E metabolites, that long-chain ω-carboxylates are potent allosteric inhibitors of 5-lipoxygenase, a key enzyme in the biosynthesis of chemoattractant and vasoactive leukotrienes. 13-((2R)-6-hydroxy-2,5,7,8-tetramethylchroman-2-yl)-2,6,10-trimethyltridecanoic acid (α-T-13′-COOH) can be synthesized from α-tocopherol in a human liver-on-chip, and is detected in human and mouse plasma at concentrations (8–49 nM) that inhibit 5-lipoxygenase in human leukocytes. α-T-13′-COOH accumulates in immune cells and inflamed murine exudates, selectively inhibits the biosynthesis of 5-lipoxygenase-derived lipid mediators in vitro and in vivo, and efficiently suppresses inflammation and bronchial hyper-reactivity in mouse models of peritonitis and asthma. Together, our data suggest that the immune regulatory and anti-inflammat...

Journal of Radioanalytical and Nuclear Chemistry, 2018

The 238 U, 226 Ra and 232 Th contents of six samples from the Mandena black sand placer deposit w... more The 238 U, 226 Ra and 232 Th contents of six samples from the Mandena black sand placer deposit were determined by gammaray spectrometry and varied from 2280 to 4600 Bq/kg, 1530 to 2900 Bq/kg and 11,600 to 25,400 Bq/kg, respectively. The activity concentration of 232 Th is significantly higher than 238 U and there is no equilibrium between 238 U and 226 Ra. Due to the gamma interferences at the line 1461 keV and very high 228 Ac activity, the 40 K was calculated through potassium analyzed using ICP-AES and varied from 1 to 19 Bq/kg. The calculated gamma absorbed dose rate ranged from 7700 to 16,700 nGy/h.

Journal of environmental radioactivity, 2017

In the present study, the K-40, U-238, Ra-226, Pb-210, Ra-228 and Th-228 activity concentrations ... more In the present study, the K-40, U-238, Ra-226, Pb-210, Ra-228 and Th-228 activity concentrations were measured in 64 samples of wastes generated from shale gas exploration in North-Eastern Poland. The measured samples consist of drill cuttings, solid phase of waste drilling muds, fracking fluids, return fracking fluids and waste proppants. The measured activity concentrations in solid samples vary in a wide range from 116 to around 1100 Bq/kg for K-40, from 14 to 393 Bq/kg for U-238, from 15 to 415 Bq/kg for Ra-226, from 12 to 391 Bq/kg for Pb-210, from a few Bq/kg to 516 Bq/kg for Ra-228 and from a few Bq/kg to 515 Bq/kg for Th-228. Excluding the waste proppants, the measured activity concentrations in solid samples oscillate around their worldwide average values in soil. In the case of the waste proppants, the activity concentrations of radionuclides from uranium and thorium decay series are significantly elevated and equal to several hundreds of Bq/kg but it is connected with the...

Uranium - Past and Future Challenges, 2014

This paper presents the assessment of radiation exposure due to inhalation of Rn-222 and its prog... more This paper presents the assessment of radiation exposure due to inhalation of Rn-222 and its progeny for workers and clients of selected thermal water spas. The evaluation of the radon risk is based on the activity concentration of Rn-222 in the investigated thermal waters. For this purpose, a radon transfer coefficient which describes a fraction of radon transferred from swimming-pool water to the indoor swimming-pool air was calculated. The evaluated annual effective dos-es for the model clients and workers range in the intervals of 0.40 μSv to 194 μSv and 0.022 mSv to 10.8 mSv, respectively.

Microelectronics Reliability, 2014

A simple fabrication scheme of using silver-filled conductive tape to form flexible single crysta... more A simple fabrication scheme of using silver-filled conductive tape to form flexible single crystalline Si-Pd Schottky diodes on a polymer substrate has been studied and reported previously. In this investigation, we studied the long term thermal stability of these flexible diodes on polymer annealed at 80°C in open air for 1 year. The I-V characteristics of the diodes were measured periodically. We found that the barrier height of the Si-Pd diodes remained relatively unchanged at 0.795 eV ± 0.003 with an n-factor of 1.03 ± 0.03, and a series resistance of $110 X for diodes with a 950 lm diameter, which are almost identical to the values before annealing. The integrated structure stayed flexible to a similar curvature after 1 year. The stability of silver-filled conductive tape was investigated separately over the same period of time and under the same conditions. The resistance of two conductive tapes was found to quickly decrease from high initial values to significantly lower values, and remained constant over the course of the investigation. Based on these results, we conclude that this simple bonding technique of using conductive tape to fabricate flexible devices can be of useful value in practical applications.