Investigation of radon and thoron concentrations in a landmark skyscraper in Tokyo

The temporal variation of the radon concentration, and the radon and thoron concentrations every 3 months for a year were measured using two types of devices in a landmark skyscraper, the Tokyo Metropolitan Government Daiichi Building. In the measurement of temporal variation of the radon concentration using a pulse type ionization chamber, the average radon concentration was 21 ± 13 Bq m^?3 (2–68 Bq m^?3). The measured indoor radon concentration had a strong relationship with the operation of the mechanical ventilation system and the activities of the office workers. The radon concentration also increased together with temperature. Other environmental parameters, such as air pressure and relative humidity, were not related to the radon concentration. In the long-term measurements using a passive radon and thoron discriminative monitor, no seasonal variation was observed. The annual average concentrations of radon and thoron were 16 ± 8 and 16 ± 7 Bq m^?3, respectively. There was also no relationship between the two concentrations. The annual average effective dose for office workers in this skyscraper was estimated to be 0.08 mSv y^?1 for 2000 working hours per year. When considering the indoor radon exposure received from their residential dwellings using the annual mean radon concentration indoors in Japan (15.5 Bq m^?3), the annual average effective dose was estimated to be 0.37 mSv y^?1. This value was 31 % of the worldwide average annual effective dose.     

Determination of Mildronate in Human Plasma and Urine by UPLC�CPositive Ion Electrospray Tandem Mass Spectrometry

A simple, rapid, and selective method to determine the concentration of mildronate in human plasma and urine using ultra performance liquid chromatography?Ctandem mass spectrometry (UPLC-MS-MS) was developed and validated. The detection was performed on a triple-quadrupole tandem mass spectrometer by multiple reaction monitoring mode via electrospray ionization at m/z 147.2?C58.0 for mildronate and m/z 147.2?C87.8 for the internal standard, carbachol. The UPLC separation was carried out with a UPLC BEH HILIC column. The mobile phase consisted of 0.08% formic acid in 30 mM ammonium acetate solution and acetonitrile (23:77, v/v). Plasma samples were extracted from plasma by protein precipitation and urine samples were diluted with the mobile phase. The analysis time was 3.5 min for each sample. Linear calibration curves ranged from 0.10 to 100.00 ??g mL^?1 in human plasma and 0.50 to 600.00 ??g mL^?1 in urine. The method had been successfully applied to a pharmacokinetic study in healthy volunteers. After single intravenously administration of 250, 500, and 750 mg mildronate, the elimination half-life (t _1/2) were (2.74 ± 0.67), (4.86 ± 0.82) and (5.16 ± 0.77) h, respectively. The t _1/2 for the 250 mg dose did vary significantly with other dosages (P < 0.05), mildronate may have non-linear pharmacokinetics in humans.     

Natural radioactivity in surface marine sediments near the shore of Vizag, South East India and associated radiological risk

Naturally occurring radioactive materials were determined in surface sediments from the marine environment near the shore of Vizag in the South eastern part of India using gamma spectrometry technique. The mean activity concentration was found to be 36 ± 11, 34 ± 15, 75 ± 38 and 782 ± 223 Bq/kg and ranged from 19 to 48 Bq/kg, 11 to 57 Bq/kg, 31 to 145 Bq/kg and 363 to 1,024 Bq/kg for ²³⁸U, ²²⁶Ra, ²³²Th and ⁴⁰K, respectively. The mean radium equivalent activity, external hazard index, air absorbed gamma dose rate and annual effective dose equivalent are 203 ± 62 Bq/kg, 0.6 ± 0.2, 94 ± 27 nGy/h and 0.12 ± 0.03 mSv/year respectively. This data will serve as the baseline level for naturally occurring radionuclides in the study area and will be useful for tracking and assessing any pollution inventory in the environment of this region.     

The Effects of Caffeine Ingestion Before Passive Heat Loading on Serum Leptin Levels in Humans

We assessed the effects of ingesting caffeine before passive heat loading (PHL) on serum leptin and sweating response, which are both physiological responses associated with energy expenditure. The subjects were nine male university students (age, 24.1?±?3.5 years; height, 173.4?±?7.6 cm; weight, 69.2?±?5.7 kg; maximal oxygen consumption, 48.6?±?4.7 ml???kg^?1???min^?1). This study used a within-subject, random, crossover design. Tests were performed twice at the same time (2–5 p.m.) at a 1-week interval following 3 mg?kg^?1 caffeine ingestion (Caff-I) or not (No-Caff). PHL included a half bath in hot water (42?±?0.5 °C for 30 min) in a thermoneutral climate chamber (25?±?0.5 °C, 60?±?3 % relative humidity, <1 m/s air velocity). After PHL, blood levels of leptin and free fatty acids were significantly higher in the Caff-I compared to those in the No-Caff after PHL (P?<?0.01). Waist circumference and whole-body sweat loss volume were significantly higher in the Caff-I compared to those in the No-Caff (P?<?0.001). Mean active sweat gland density was significantly higher in the Caff-I compared to those in the No-Caff at 10 min during PHL (P?<?0.001). The results suggest that ingesting caffeine before PHL is more energy efficient than that of a single PHL.     

Potassium concentrations and annual effective dose of the customary food stuffs in Mexico

Measurement of radionuclides concentration in foodstuffs allows to assess the intake’s assimilated dose. This contributes at least one-eighth of the mean annual effective dose due to natural sources. Among the trace elements in foodstuff, potassium is one of the most important elements. It is a well-known essential element and it occurs all over the earth. Three of the most customary consumed foodstuffs in Mexico since pre-Hispanic time (by all social classes) are the following: bean, chili and corn meal (“tortillas”). They were analyzed by γ-spectrometry in order to determine ⁴⁰K activity concentration, the derived annual effective dose, and the K mass fraction (%). Results show that the mean activity concentration of ⁴⁰K, annual effective dose and K mass fraction (%) are as follow: 901 ± 90 Bq kg^?1, 37.2 ± 3.7 μSv a^?1 and 2.84 ± 0.27 % for chili; 510 ± 10 Bq kg^?1, 27.5 ± 0.5 μSv a^?1 and 1.60 ± 0.04 % for bean; and, 90 ± 30 Bq kg^?1, 58.1 ± 19.4 μSv a^?1 and 0.27 ± 0.089 % for corn meal, “masa”. The total effective dose intake from these typical foodstuffs is about 0.122 ± 15.6 mSv a^?1in Mexico’s urban zones.     

Natural radioactivity of geothermal water in Beijing,China

In this work, we collected 101 geothermal water samples to investigate comprehensively the radioactivity of geothermal water in Beijing. The concentrations of gross beta, ²²⁶Ra and ²²²Rn were measured and the obtained values were in the range of 0.032–7.060, 0.023–0.363 and 0.470–29.700 Bq/L, respectively. The samples with higher concentration of ²²²Rn were found to be located near large faults. The effective dose of ²²²Rn in the air for three cases were calculated to be greater than radiation dose limit of 1 mSv/a.     

Radiation doses at high altitudes and during space flights

There are three main sources of radiation exposure during space flights and at high altitudes—galactic cosmic radiation, solar cosmic radiation and radiation of the earth's radiation belt. Their basic characteristics are presented in the first part of this paper.Man's exposure during space flights is discussed in the second part of the paper. Particular attention is devoted to the quantitative and qualitative characteristics of the radiation exposure on near-earth orbits: both theoretical estimation as well as experimental data are presented. Some remarks on radiation protection rules on-board space vehicles are also given.The problems connected with the radiation protection of air crew and passengers of subsonic and supersonic air transport are discussed in the last part of the paper. General characteristics of on-board radiation fields and their variations with flight altitude, geomagnetic parameters of a flight and the solar activity are presented, both based on theoretical estimates and experimental studies. The questions concerning air crew and passenger radiation protection arising after the publication of ICRP 60 recommendation are also discussed. Activities of different institutions relevant to the topic are mentioned; strategies to manage and check this type of radiation exposure are presented and discussed. Examples of results based on the author's personal experience are given, analyzed and discussed.     

Synthesis and thermal properties of NiSbS–As doped phase

The substitution of Sb with As in the NiSbS intermetallic compound was studied in the framework of evaluating a possible increase of the thermoelectric properties. Different NiSb_1?xAs_xS samples were synthesized with increasing amounts of As (0 < x < 0.66) employing a simple synthetic route using a muffle furnace. Scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy was used to investigate the microstructure. X-ray powder diffraction techniques were employed in order to study the possible existence of a solid solution between NiSbS and NiAsS compounds, as well as to identify the crystal structure and determine the lattice parameters. All compounds were found to crystallise with the NiSbS prototype (cP12-P2₁3), with lattice parameters varying from a = 0.59341(7) nm (x = 0) to a = 0.56849(6) nm (x = 1). Good agreement with Vegard’s law was evidenced. Thermal measurements on NiSb_1?xAs_xS samples were carried out using DTA instruments to evaluate the thermal stability and the melting temperatures.     

Development of a Sensitive LC Assay with Fluorescence Detection for the Determination of Zearalenone in Rat Serum

A simple and sensitive liquid chromatographic assay with fluorescence detection assay was developed for the determination of zearalenone levels in rat serum. The assay utilized a single liquid–liquid extraction with t-butyl methyl ether and isocratic elution using a mobile phase consisting of acetonitrile and 0.1% triethylamine in distilled water (pH = 6) (50:50, v/v). Linearity was observed over a concentration range from 10 to 1,000 ng mL^?1 (r = 0.9995), with the limit of quantification at 10 ng mL^?1 with 100 μL of rat serum. The validated assay was applied to a pharmacokinetic study in rats.     

A study of thermal and dielectric behavior of melaminium perchlorate monohydrate single crystals

Single crystals of melaminium perchlorate monohydrate (MPM) have been grown from aqueous solution by slow solvent evaporation method at room temperature. X-ray powder diffraction analysis confirms the title crystal crystallizes in the triclinic (P-1) structure and the calculated lattice parameters are a = 5.6275 ± 0.0780 Å, b = 7.6926 ± 0.1025 Å, c = 12.0878 ± 0.2756 Å, α = 103.89 ± 1.01°, β = 94.61 ± 0.92°, γ = 110.22 ± 0.81°, and V = 468.95 Å³. The thermal decomposition behavior of MPM has been studied by means of thermogravimetric analysis at three different heating rates 5, 10, and 20 °C min^?1. The values of effective activation energy (E _a), pre-exponential factor (ln A) of each stage of thermal decomposition for all heating rates were calculated by model free method: Kissinger, Kim–Park, and Flynn–Wall method. A significant variation of effective activation energy (E _a) with conversion (α) indicates that the process is kinetically complex. The linear relationship between the A and E _a values was established (compensation effect). Dielectric study has also been carried out and it is found that both dielectric constant (ε′) and dielectric loss (ε″) decreases with increase in frequency.     

Suitable dose of 60Co γ-ray for mutation in Roegneria seeds

Seeds from six accessions of three species of Roegneria were radiated with ⁶⁰Co γ-ray at different doses (50, 100, 150, 200, 250, 300 and 400 Gy). Following these treatments, germination energy, germination rate, seedling height, plant height, plant survival, and seed set were observed. Plant survival was highly correlated with seedling height (R ² > 0.91, P < 0.01) and seed set (R ² > 0.82, P < 0.01). The semi-lethal dose of each accession, calculated using a ‘Multi-target single-hit’ model, ranged from 60 to 173 Gy. The most suitable absorbed doses for each accession were deduced from these data. The suitable doses for Roegneria kamoji, Roegneria ciliaris and Roegneria japonensis were 65–100 Gy, 63–150 Gy and 80–170 Gy, respectively. According to the range of suitable doses, R. kamoji (Pr87-88-353) was the most sensitive to radiation, and R. japonensis (88-89-267) was the most resistant to radiation. Suitable doses of R. ciliaris were close to that of R. kamoji (ZY1007). This research provides preliminary guidelines for radiation induced mutagenesis in Roegneria.     

Measurements of natural radioactivity in infant formula and radiological risk assessment

A set of measurements have been conducted to determine the levels activity of gamma-emitters present in infant formula. The study of different samples shows the presence of the following radionuclides: ²²⁶Ra, ²³²Th and ⁴⁰K with respectively average activity of 0.52 ± ?0.087, 0.51 ± 0.062, 371.98? ± 3.68 Bq/kg. The mean annual doses lead to 0.62 and 0.24 mSv/year whereas the total risk is about 7.91 × 10^?6 and 5.32 × 10^?6 respectively ≤ 1 year and 1–2 years old infants. The obtained results show that no significant radiation dose and no risk to the infants due to consumption of these milks.     

The molecular structures of tris(dipivaloylmethanato)chromium and tris(dipivaloylmethanato)cobalt determined by gas electron diffraction and density functional theory calculations

The molecular structures of tris(dipivaloylmethanato)chromium and tris(dipivaloylmethanato)cobalt have been determined by quantum chemical calculations and gas electron diffraction. Both the experimental data and the theoretical results are consistent with molecular structures having D ₃ symmetry which is in agreement with the Kepert model. The experimental bond distances, r _h1(Å), and bond angles, ∠ _h1(°), are: Cr–O = 1.976(5), C–O = 1.287(3), C–C_r = 1.392(6), C–C_t = 1.547(3), OCrO = 90.1(0.9), CC_rC = 122.3(0.9), OCC_t = 114.7(0.9) and Co–O = 1.891(4), C–O = 1.269(3), C–C_r = 1.411(5), C–C_t = 1.546(3), OCoO = 95.2(0.5), CC_rC = 122.5(0.9), OCC_t = 115.1(0.8).     

Statistical assessment of radiological data of tiles collected from Jordan

ABSTRACT

In this present study, activity concentration of natural radionuclides such as ²²⁶Ra, ²³²Th and ⁴⁰K were determined using gamma ray spectrometer based on High Purity Germanium (HPGe) detector in ceramic tiles collected from Jordan. The average activity concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K were found to be 63.75 ± 24.12, 93.65 ± 13.89 and 180.9 ± 45.69 Bq.kg^?1. respectively. Using activity concentration of ²²⁶R, ²³²Th and ⁴⁰K, the radiological parameters such as radium equivalent activity (Ra_eq), Criteria formula (CF), absorbed dose rate (D_R), annual effective dose rate (H_R), activity utilisation index (AUI), external hazard index (H_ex), international hazard index (H_in), alpha index and gamma index (I_γ) has been calculated to assess the radiation hazards in the Tiles. The calculated average value of all radiological parameters is less than the recommended limit. The calculated values of annual effective dose rate (H_R), show that about 30% of the samples exceeded the recommended limit of 1 mSv.y^?1. Moreover, multivariate statistical techniques such as Pearson correlation, factor and cluster analysis were performed between the radioactive variables to know the existing relation between them.     

The research on formation enthalpy of phenanthroline monohydrate and its influence on the growth metabolism of E. coli by microcalorimetry

A precision rotating-bomb combustion calorimeter (thermistor of which was constructed in the laboratory) was calibrated using benzoic acid with purity of 99.999 %. The combustion energy of phenanthroline monohydrate (phen·H₂O) at 298.15 K was determined to be Δ_c U _m ^θ  = ?(5,757.45 ± 2.53) kJ mol^?1. Then, the standard enthalpy of combustion and the standard enthalpy of formation of phen·H₂O were calculated to be Δ_c H _m ^θ  = ?(5,759.93 ± 2.53) kJ mol^?1 and Δ_f H _m ^θ  = ?(391.34 ± 2.98) kJ mo1^?1, respectively. Particularly, the effect of phen·H₂O on growth and metabolism of Escherichia coli (E. coli) was also determined by a TAM air isothermal calorimeter at 37 °C. The thermokinetic parameters, including maximum heat output power (P _max), growth rate constant (κ), generation times (t _G), inhibitive rate (I), and half inhibition concentration (C _I,50), were obtained. The results showed that phen·H₂O possessed the bi-directional biological effect and Hormesis effect, which stimulated the growth of E. coli at lower concentration, but inhibited the growth at higher concentration. The half inhibition concentration C _I,50 of phen·H₂O was found to be 7.31 mg L^?1.     

Thermal stability and band gap study of heavy metal oxy-sulfide glass system

Novel oxy-sulfide glass system xPbS-(73 ? x) Bi₂O₃–27B₂O₃ with 6.06 ≤ x ≤ 36.35 named lead sulfide bismuth borate (LSBB) was prepared using normal melt and quench-casting technique. Phase transition temperatures t _g, t _x, t _pi, and t _l were noted from the DTA curves. Glass transition temperature t _g varied from 306 ± 2 to 336 ± 2 °C and the onset of crystallization temperatures t _x was between 331 ± 2 and 402 ± 2 °C. The glasses melted in the range 523 ± 2 to 597 ± 2 °C. The ratio t _g /t _l showed that compositions reported conform to the two-third law of glass formation. Hruby’s coefficient H _r witnessed the thermal stability of the system and that LSBB4 was most stable and glass formability factor k _gl showed that composition LSBB1–LSBB6 can easily corroborate vitreous state. The direct band gap energy varied from 1.56 to 3.07 eV, while indirect band gap energy for the fundamental absorption edge was 0.21–1.31 eV. Absorption edges obeyed Urbach rule. A broad range of band tailing was exhibited confirming amorphous state of the system.     

Geochemistry and health burden of radionuclides and trace metals in shale samples from the North-Western Niger Delta

Organic sedimentary rock samples were collected from three Oil Wells in the North-Western Niger Delta, Nigeria in order to determine their natural radioactivity and elemental geochemistry, with the aim of determining the concentrations of major radionuclides and their radiological and environmental health implication. The PIXE method of IBA technique and an accurately calibrated Si(Li) detector system was used to measure the elemental concentration of the sediment samples. The radionuclides identified belong to the decay series of naturally occurring radionuclides headed by ²³⁸U and ²³²Th along with the non-decay series radionuclide, ⁴⁰K. The activity concentrations of the radionuclides and their derived dose were then calculated. The average activity concentrations of ⁴⁰K were 248 Bq/kg for Well A, 261 Bq/kg for Well B and 273 Bq/kg for Well C. For ²³²Th the activity concentrations were 1,043 Bq/kg for Well A, 1,400 Bq/kg for Well B, 1,434 Bq/kg for Well C. ²³⁸U activity concentrations were 2,210, 3,508 and 250 Bq/kg for the Oil Wells A, B, C, respectively. The equivalent dose ranges from 8.5 ± 1.1 to 24.3 ± 2.1 mSv/year with a mean of 14.5 ± 2.2 mSv/year for Oil Well A, 2.4 ± 0.1–75.0 ± 1.2 mSv/year with a mean of 21.5 ± 1.1 mSv/year for Oil Well B and 3.7 ± 0.2–10.7 ± 0.6 mSv/year with a mean of 9.4 ± 2.5 for Oil Well C. The detected trace metals were majorly V, Ni, Pb, Fe, Cr, Cu, Zn, Co and their concentrations together with those of the radionuclides are compared with the relevant world standard limits. The results obtained were high, and hence, the radioactivity level and trace element content of the sediment samples from the North-Western Niger Delta Oil province could constitute health hazard to occupationally exposed workers, and to the public if not properly disposed. However, despite the careful disposal practice claims by the Oil industries, and given the high concentrations, the sediments could still pose an intrinsic health hazard considering their cumulative effects in the environment.     

Polyaniline/montmorillonite nanocomposite thin layers deposited on different substrates

Preparation method of polyaniline/montmorillonite (PANI/MMT) nanocomposite in the form of thin layer deposited on various substrates is optimized in this work to obtain high electrical conductivity. Simple method (i.e. polymerization of anilinium sulfate in the presence of MMT) has been used for the preparation and following four conditions were varied: preparation temperature (T = 10 or 20 °C), preparation time (t = 4 or 6 h), size fraction of MMT (p < 1 or 5 µm), and type of substrate (microscope glass slides, silica glass slides, polyester foils). Therefore, 24 samples were prepared, characterized and their electrical conductivity was compared. Raman spectroscopy and scanning electron microscopy were used for the characterization of the structure of samples. Thickness of layers was measured using atomic force microscopy. Based on the comparison of samples and with respect to the aim of obtaining high electrical conductivity, it was found that the most suitable substrate is polyester foil and preparation conditions are T = 20 °C, t = 6 h, p < 5 µm. To obtain highly conductive layers on glass substrates (although less conductive than layers on foil), preparation time have to be shortened to 4 h.     

Determination of Aldoses, Deoxy-aldoses and Uronic Acids Content in a Pectin-Rich Extract by RP-HPLC-FLD after p-AMBA Derivatization

A reversed-phase high-performance liquid chromatographic method with fluorometric detection is proposed for the simultaneous determination of different classes of neutral sugars, such as hexoses (galactose, glucose and mannose), pentoses (arabinose and xylose), deoxy-hexoses (fucose and rhamnose), as well as acidic sugars (galacturonic and glucuronic acids). The separation is carried out on a hydrophilic end capped C₁₈ column following a pre-column derivatization with p-aminobenzoic acid. The fluorometric detection of the derivatives has shown a strong dependency with the mobile phase pH. The performance of the proposed methodology was evaluated and the prerequisites of linearity (r-value > 0.999), precision (intra-day CV < 6 % and inter-day CV < 11 %) and recovery (between 77 ± 7 and 103 ± 3 %) were satisfied. To our knowledge, the obtained values of limit of detection for neutral sugars (within the range 6.1–28 μg L^?1) are the lowest reported using this derivatizing agent. In order to better judge the methodology presented herein, neutral sugars of a pectin-rich orange extract were also analysed by the conventionally used GC-FID (gas-chromatography with flame ionization detector) method of alditol acetate derivatives. A statistical test (paired t test) has proved that no significant differences (α = 0.05) were observed between these two methods.     

Evaluation of radon concentration and heavy metals in drinking water and their health implications to the population of Quetta,Balochistan, Pakistan

ABSTRACT

The purpose of this study is to estimate the concentrations of radon and heavy metals in drinking water and assess their health implications to the population of Quetta, Pakistan. The concentration of radon and heavy metals was measured in drinking water collected from tube wells of different depths of the Quetta, Balochistan, Pakistan, using RAD7 detector and Atomic Absorption Spectrometer, respectively. The results show that the concentration of radon ranged from 3.56 ± 0.98 to 8.56 ± 1.32Bq/L with an average of 5.67 ± 1.34Bq/L. The average value of contribution of radon in water to indoor air was found 2.02 ± 0.47mBq/L. In addition to concentration of radon in drinking water, physiochemical parameters like pH and electrical conductivity (EC), and annual effective doses for different age groups were also estimated. Positive correlation of (R² = 0.8471) was observed between depth of well and concentration of radon, however no such relations were found among pH and EC with concentration of radon. Average values of annual effective doses due to intake of radon for age groups 0–1 years (infants), 2–16 years (Children) and ≥17 years (adults) were found (3.00 ± 0.71)×10^?2, (1.1 ± 0.26)×10^?2 and (1.45 ± 0.34)×10^?2 mSv/y, respectively. Average values of heavy metals concentrations were found 1.85 ± 0.64, 3.21 ± 0.75, 5.06 ± 1.19, and 2.47 ± 0.77 and 5.58 ± 1.23 µg/L for As, Cr, Ni, Cd and Pb, respectively. The values of radon concentration and heavy metals in drinking water were found below the USEPA permissible limits, Thus we conclude that, the investigated waters are safe.