Abstract  Hierarchically porous TiO(2)/ZrO(2) millimeter-sized beads were synthesized using a sol-gel templating technique, and investigated for suitability as radionuclide sorbents using uranyl as a radionuclide-representative probe. The bead properties were varied by altering either composition (22, 36, and 82 wt % Zr in the Ti/Zr composite) or calcination temperature (500 or 700 °C). Uranyl adsorption was higher for the crystalline beads (surface area: 52-59 m(2) g(-1)) than the amorphous beads (surface area: 95-247 m(2) g(-1)), reaching a maximum of 0.170 mmol g(-1) for the 22 wt % Zr sample. This was attributed to the higher surface hydroxyl density (OH nm(-2)), presence of limited microporosity, and larger mesopores in the crystalline beads. Mass transport properties of the crystalline beads were not compromised by the large bead diameter: sorption rates comparable to those reported for powders were achieved and rates were higher than exclusively mesoporous reported systems, thereby highlighting the importance of pore hierarchy in designing materials with improved kinetics. Chemical stability of the sorbent, an important property for processes involving corrosive effluents (e.g., radioactive waste), was also assessed. Crystalline beads displayed superior resistance against matrix leaching in HNO(3). Stability varied with composition: the 22 wt % Zr sample demonstrated the highest stability.

Abstract  OBJECTIVE: The ependymal cells, considered today as an active participant in neuroendocrine functions, were investigated by electron microscopy in the central canal of the lowest spinal cord, the filum terminale (FT), in adult rats. In this area of the spinal cord, the central canal is covered by a heterogeneous population of ependymal cells. The aim of the present work was to compare the regional features of the ependymal cells in two different parts of the FT with a special regard to their ultrastructure.

METHODS: Two parts of the FT were selected for the ultrastructural observations: the rostral (rFT) and the caudal (cFT) ones. The rTF was removed at the level of the immediate continuation of the conus medullaris, while the cFT 30 mm further caudally. After formaldehyde fixation, the spinal cord was removed and cut into small blocks for electron microscopic processing. The material was embedded into durcupan, contrasted with uranyl acetate, lead citrate as well as osmium tetroxide, and investigated under JEOL 1200 EX electron microscope.

RESULTS: In the rFT, the ependymal lining is pseudostratified and one-layered in the cFT, whereas the shape of the ependymal cells may vary from cuboidal to flatten in the rostro-caudal direction. The basal membrane of many ependymal cells possesses deep invaginations, so called "filum terminale labyrinths". Many neuronal processes occur in the pericanalicular neuropil. In contrast to the rFT, the cFT is less rich in the neuropil particles. Some of the ependymal cells concurrently reach both the intracanalicular and extracanalicular cerebrospinal fluid (CSF), thus they may represent a new variant of the ependymal cells designated as "bridge cells of the FT".

CONCLUSIONS: The present data indicate that the FT ependymal cells exhibit clear differences in anatomy as well as ultrastructure that may reflect their distinct functional activity. Therefore, observations presented here may serve for the better understanding of the physiological role of the individual ependymal areas in this special portion of the rat spinal cord.

Abstract  The aim of this study is to propose a novel data analysis approach, an analysis of characterizing phases (ACP), that detects and examines phases of variance within a sample of curves utilizing the time, magnitude, and magnitude-time domains; and to compare the findings of ACP to discrete point analysis in identifying performance-related factors in vertical jumps. Twenty-five vertical jumps were analyzed. Discrete point analysis identified the initial-to-maximum rate of force development (P=.006) and the time from initial-to-maximum force (P=.047) as performance-related factors. However, due to intersubject variability in the shape of the force curves (ie, non-, uni- and bimodal nature), these variables were judged to be functionally erroneous. In contrast, ACP identified the ability to apply forces for longer (P<.038), generate higher forces (P<.027), and produce a greater rate of force development (P<.003) as performance-related factors. Analysis of characterizing phases showed advantages over discrete point analysis in identifying performance-related factors because it (i) analyses only related phases, (ii) analyses the whole data set, (iii) can identify performance-related factors that occur solely as a phase, (iv) identifies the specific phase over which differences occur, and (v) analyses the time, magnitude and combined magnitude-time domains.

Abstract  The importance of bacteria in the anaerobic bioremediation of groundwater polluted with organic and/or metal contaminants is well recognized and in some instances so well understood that modeling of the in situ metabolic activity of the relevant subsurface microorganisms in response to changes in subsurface geochemistry is feasible. However, a potentially significant factor influencing bacterial growth and activity in the subsurface that has not been adequately addressed is protozoan predation of the microorganisms responsible for bioremediation. In field experiments at a uranium-contaminated aquifer located in Rifle, CO, USA, acetate amendments initially promoted the growth of metal-reducing Geobacter species, followed by the growth of sulfate reducers, as observed previously. Analysis of 18S rRNA gene sequences revealed a broad diversity of sequences closely related to known bacteriovorous protozoa in the groundwater before the addition of acetate. The bloom of Geobacter species was accompanied by a specific enrichment of sequences most closely related to the ameboid flagellate, Breviata anathema, which at their peak accounted for over 80% of the sequences recovered. The abundance of Geobacter species declined following the rapid emergence of B. anathema. The subsequent growth of sulfate-reducing Peptococcaceae was accompanied by another specific enrichment of protozoa, but with sequences most similar to diplomonadid flagellates from the family Hexamitidae, which accounted for up to 100% of the sequences recovered during this phase of the bioremediation. These results suggest a prey-predator response with specific protozoa responding to increased availability of preferred prey bacteria. Thus, quantifying the influence of protozoan predation on the growth, activity and composition of the subsurface bacterial community is essential for predictive modeling of in situ uranium bioremediation strategies.

Abstract  This study was a material compatibility assessment of four metals (beryllium, stainless uranium, 304L stainless steel, and 2024-T3 aluminum) with an environmentally benign, non-aqueous, near-azeotropic mixture of hydrofluoroether (Novec (TM) 7100) with 4.5 wt% isopropanol designated Novec (TM) 71 IPA. The intent is to use the Novec (TM) 71 IPA to clean materials in sensitive, long-term assemblies. There is concern when an aged solvent is used to clean a metal surface, it may cause corrosion due to fluoride formation as the solvent ages. Two solvent conditions, one having no detectable fluoride (fresh) and the other with >= 17 ppm fluoride (aged) were evaluated. Electrochemical evaluations using impedance spectroscopy were performed to monitor the metal surfaces for signs of reaction. Microscopic and spectroscopic techniques, including X-ray photoelectron spectroscopy, were used to characterize the metal surfaces before and after electrochemical tests. Increased impedance was observed when beryllium substrates were exposed to fresh or aged Novec (TM) 71 IPA and was attributed to formation of organic and/or inorganic films on native beryllium oxide. Other metals exhibited insignificant changes in impedance but did show some passive film formation. Results confirmed Novec (TM) 71IPA, containing up to 17 ppm fluoride, had no corrosive effect on the four tested metals and may be used to safely clean them. (C) 2012 Elsevier Ltd. All rights reserved.

Abstract  In order to satisfy the mass spherical fuel elements (SFE) requirements for the High Temperature gas-cooled Reactor (HTR)-Pebble bed Module (HTR-PM), a modified and optimized fabrication of dense uranium dioxide (UO2) kernel via an acid-deficiency uranium nitrate (ADUN) solution was researched and developed in the institute of nuclear and new energy technology (INET). In this study, external gelation process of uranium (EGU) based on the total gelation of uranium (TGU) in the period of 10 MW HTR (HTR-10) was used to prepare the ammonium diuranate (ADU) compound particles, an intermediate for UO2 kernel. The scale of batch production was improved from 500g U/batch at that time to current 3 kg U/batch. Improvements in many aspects such as large scale preparation of ADUN, multiple-nozzle casting system and new aging, washing and drying (AWD) system without isopropanol were also presented. Under strict controls and measures. ADU particles with good sphericity and uniform diameter were acquired to ensure the subsequent preparation of dense UO2 kernels for HTR-PM. (C) 2012 Elsevier B.V. All rights reserved.

Abstract  Complexes of uranyl(VI) (U(VI)) with tridentate ligands derived from salicylaldehyde and aminoacids are reported, bis 2-((2-hydroxybenzylidene)amino) acetic acid U(VI), UO2(SalGly)(2) (1); tri aqua 2-((2-hydroxybenzylidene)amino)propanoic acid U (VI) nitrate, [UO2(SalAla)(H2O)(3)]NO3 (2); tri aqua 3-hydroxy-2-((2-hydroxybenzylidene)amino) propanoic acid U(VI) nitrate, [UO2(SalSer)(H2O)(3)]NO3 (3); tri aqua 2-((2-hydroxybenzylidene) amino)-3-methylbutanoic acid U(VI) nitrate, [UO2(SalVal)(H2O)(3)]NO3 (4), and tri aqua 2-((2- hydroxybenzylidene)amino)-4-(methylthio)butanoic acid U(VI) nitrate, [UO2(SalMet)(H2O)(3)]NO3 (5). The characterization of the complexes was performed by electrospray mass spectroscopy, ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy, nuclear magnetic resonance, fluorescence spectroscopy, and thermal analysis. The complexes are electrolytes (1 : 1) having a molar ratio M: L = 1 : 1, except 1, which is a nonelectrolyte with a molar ratio M: L = 1 : 2. The fluorescence intensity of the complexes is more intense than uncomplexed uranyl, except 1 and 5. High fluorescence of the uranyl SalAla complex (2) was used to assess complexes- DNA interaction based on fluorescence quenching assay. The interaction of 2 with DNA was assessed by measuring the relative fluorescence quenching of the complex when nucleic acids were added.

Abstract  In order to develop a direct separation process for trivalent minor actinides from fission products in high level liquid waste (HLLW) by extraction chromatography, a novel macroporous silica-based 2,6-bis(5,6-diisohexyl)-1,2,4-triazin-3-yl) pyridine resin (isohexyl-BTP/SiO2-P resin) was prepared. The content of isohexyl-BTP extractant in the resin was as high as 33.3 wt%. The resin exhibited much higher adsorption affinity for Am (III) in 2-3 M (mol/L) HNO3 solution over U and FP which are contained in HLLW. The kinetic data were analyzed using pseudo-second-order equation. The results suggested that the Eu(III), Gd (III), and Dy(III) adsorption was well explained by the pseudo-second-order equation. Quantitative desorption for adsorbed elements was achieved by using H2O or thiourea as eluting agents. However, the kinetics of adsorption and desorption were rather slow and this drawback needs to be resolved. Stability of the resin against HNO3 was also examined. It was found that the resin was considerably stable against <= 4 M HNO3 solution for the reasons of an extremely small leakage of the extractant into the solution from the resin and the adsorption performance keeping for rare earths in 3 M HNO3 solution.

Abstract  A thin film of well-ordered anatase TiO2 nanotubes prepared by anodic oxidation of titanium metal were synthesised and used as adsorbent medium for the purification of water from aqueous uranium and lead. The amount of subtracted metal ions was quantified by using X-ray photoelectron spectroscopy at the surface of the reacted TiO2 surface. Batch experiments for the sorption of U and Pb at the surface of the titania substrate were carried out in separated solution equilibrated with air of uranyl acetate and lead nitrate, in the pH range 3-9. For uranium, the experiments were also repeated in anoxic (N-2) atmosphere. The amount of metal ions adsorbed onto the titania medium was quantified by measurements of the surface coverage expressed in atomic percent, by recording high-resolution XPS spectra in the Ti2p, U4f and Pb4f photoelectron regions. Adsorption of the uranyl species in air atmosphere as a function of pH showed an adsorption edge near pH 4 with a maximum at pH 7. At higher pH the presence of very stable uranyl-carbonate complexes prevented any further adsorption. Further adsorption increased until pH 8.5 was obtained when the uranyl solution was purged from dissolved CO2. Lead ion showed a sorption edge at pH 6, with a maximum uptake at pH 8. The results showed that the uptake of uranium and lead on the selected titania medium is remarkably sensitive to the solution pH. This study demonstrates the reliability of this type of material for treating water polluted with heavy metals as well as leachates from radioactive nuclear wastes.

Abstract  Towards development of electrical conductivity based sensors for online detection of formation of third phase during reprocessing of Pu rich spent nuclear fuels, laboratory studies were carried out using U4+ solutions in various experimental conditions. Third phases were generated by extracting U4+ from nitric acid medium by 1.09 M TBP at different A/O (A: aqueous, O: organic) ratios. The results of this study indicate that the third phase is nearly 100-300 times more conducting than lean organic phase and saturated phase. The higher conductivity of third phase as compared to that of other two phases is explained based on the principle of reverse micelle formation and charge movement between the micro emulsion globules by percolation phenomenon.

Abstract  Micronuclei can be used as markers of past radiation exposure, but few pertinent studies have dealt with alpha radiation. Here we report on micronuclei in lymphocytes from uranium miners, comparing some that are currently active and others that retired 15-20 years ago. Their radiation exposure is assumed to come mainly from radon and its decay products in the air breathed at the work place. Current miners showed a greater micronucleus frequency than former miners. This can be attributed to their recent radiation exposure, while the lower frequency in the former miners probably results from the disappearance of potentially micronucleus containing lymphocytes from the peripheral blood, which is known to occur with a half-life of about one year. For current miners there is a significant correlation between micronucleus frequency and effective dose received over the last 12 months. The dose at which a doubling of the micronucleus frequency is observed is around 10 mSv. This is a much smaller dose than would usually be expected to be detectable with this test, and raises a number of questions about the induction of micronuclei by alpha radiation from radon and its decay products.

Abstract  Inhalation of radon ((222)Rn) and daughter products are a major source of natural radiation exposure. Keeping this in view, seasonal indoor radon measurement studies have been carried out in 68 dwellings belonging to 17 residential areas in Alexandria city, Egypt. LR-115 Type 2 films were exposed for four seasons of 3 months each covering a period of 1 y for the measurement of indoor radon levels. Assuming an indoor occupancy factor of 0.8 and a factor of 0.4 for the equilibrium factor of radon indoors, it was found that the estimated annual average indoor radon concentration in the houses surveyed ranged from 45 ± 8 to 90 ± 13 Bq m(-3) with an overall average value of 65 ± 10 Bq m(-3). The observed annual average values are greater than the world average of 40 Bq m(-3). Seasonal variation of indoor radon shows that maximum radon concentrations were observed in the winter season, whereas minimum levels were observed in the summer season. The season/annual ratios for different type of dwellings varied from 1.54 to 2.50. The mean annual estimated effective dose received by the residents of the studied area was estimated to be 1.10 mSv. The annual estimated effective dose is less than the recommended action level (3-10 mSv y(-1)).

Abstract  Rational and balanced nutrition practice is not only an important determinant of health, but also a major factor in preventing and reducing the risk of chronic no communicable diseases. Eating disorders are the leading factors in the development of most non-communicable diseases, so this problem should be considered with health and social care, hygiene and preventive points of view. In connection with aforesaid it is necessary to study features of workers’ nutrition, to establish the factors and conditions, which influence on them, to exploit corresponding recommendation by optimization. Workers aged 35 – 50 took part in investigation of hygienic estimation of actual nutrition. In result of investigation of nutrition it was determinated that energetically asset of workers’ ration was lower than recommended standard, in average 2558 ±59 kkal. Consumption of proteins composed 86±2 g/day, for the account of them 14 % of the general caloric content of a ration are satisfied. The revealed misbalance in nutrition is essential factor of development risk of functional breaking of workers and demand obligatory correction.

Abstract  This study was carried out to assess the radiological impact of Syrian phosphogypsum (PG) piles in the compartments of the surrounding ecosystem. Estimating the distribution of naturally occurring radionuclides (i.e. (226)Ra, (238)U, (232)Th, (210)Po and (210)Pb) in the raw materials, product and by-product of the Syrian phosphate fertilizer industry was essential. The data revealed that the concentrations of the radionuclides were enhanced in the treated phosphate ore. In PG, (226)Ra content had a mean activity of 318 Bq kg(-1). The uranium content in PG was low, ca. 33 Bq kg(-1), because uranium remained in the phosphoric acid produced. Over 80% of (232)Th, (210)Po and (210)Pb present partitioned in PG. The presence of PG piles did not increase significantly the concentration of (222)Rn or gamma rays exposure dose in the area studied. The annual effective dose was only 0.082 mSv y(-1). The geometric mean of total suspended air particulates (TSP) ca. 85 μg m(-3). The activity concentration of the radionuclides in filtrates and runoff waters were below the detection limits (ca. 0.15 mBq L(-1) for (238)U, 0.1 mBq L(-1) for (232)Th and 0.18 mBq L(-1) for both of (210)Po and (210)Pb); the concentration of the radionuclides in ground water samples and Qattina Lake were less than the permissible limits set for drinking water by the World Health Organisation, WHO, (10, 1 and 0.1 Bq L(-1) for (238)U, (232)Th and both of (210)Po and (210)Pb, respectively). Eastern sites soil samples of PG piles recorded the highest activity concentrations, i.e. 26, 33, 28, 61 and 40 Bq kg(-1) for (226)Ra, (238)U, (232)Th, (210)Po and (210)Pb, respectively, due to the prevailing western and north-western wind in the area, but remained within the natural levels reported in Syrian soil (13-32 Bq kg(-1) for (226)Ra, 24.9-62.2 Bq kg(-1) for (238)U and 10-32 Bq kg(-1) for (232)Th). The impact of PG piles on plants varied upon the plant species. Higher concentrations of the radionuclides were recorded for grass in comparison to broad-leaved plants. Among the species that grow naturally on PG piles, Inula, Ecballium and Polygonium may be radionuclides accumulators. A determined effort is needed at a national level to achieve a common and coherent approach to regulate PG piles or to consider it a resource material rather than waste or residue.

Abstract  In order to assess the reliability of Monte Carlo (MC)-based numerical calibration of in vivo counting systems the EURADOS network supported a comparison of MC simulation of well-defined experiments. This action also provided training for the use of voxel phantoms. In vivo measurements of enriched uranium in a thoracic phantom have been carried out and the needed information to simulate these measurements was distributed to 17 participants. About half of the participants managed to simulate the measured counting efficiency without support from the organisers. Following additional support all participants managed to simulate the counting efficiencies within a typical agreement of +/- 5% with experiment. (C) 2012 Elsevier Ltd. All rights reserved.

Abstract  The naturally occurring radionuclides potassium-40 (K-40), radium-226 (Ra-226), polonium-210 (Po-210), and lead-210 (Pb-210) were measured in commercial fish species such as cod, halibut, redfish, and shark from several fishing grounds in the North Atlantic, as well as the anthropogenic radionuclides caesium-137 (Cs-137) and plutonium isotopes (Pu-238 and Pu239+240). The concentrations of naturally occurring radionuclides were compared with those of anthropogenic origin. The main contributors to the radiation dose were Po-210 and K-40, with anthropogenic radionuclides accounting for just a small contribution. We provide the first measurements of naturally occurring radionuclides in abyssal organisms, including fish, molluscs, and crustaceans, from the Porcupine Abyssal Plain. In these organisms, radionuclide concentrations and the absorbed radiation doses were dominated by Po-210 and were comparable with those determined in related coastal species, confirming that the deep-sea fauna do not live in an environment protected from ionizing radiation. Absorbed radiation doses from naturally occurring radionuclides still exceed radiation doses caused by anthropogenic radionuclides introduced into the Northeast Atlantic.

Abstract  The radiotoxic hazard of waste from fusion power plants has been compared with that of fission power and radioactive trace elements in coal ash within some research programs such as SEAFP and SEIF. Within another program, in 2005 a Power Plant Conceptual Study (PPCS) has been finalized investigating 4 fusion power plant models A to D. In this paper, the radiotoxicity of model B is compared with a fission power plant, concentrating on the production of wastes. The hazard of the respective masses of enriched uranium before use in a fission power plant and coal ash of a power plant generating the same amount of electricity are used as benchmarks. It is evident that the development of ingestion and inhalation hazard of the PPCS model B is different from the results of earlier studies because of different assumptions on material impurities and other constraints. An important aspect is the presence of actinides in fusion power plant waste.

Abstract  This paper explores the impact of major glacial/interglacial paleohydrologic variations in the Middle-Paleolithic Levant on hominin migration and occupation. The climatic reconstruction is based primarily on the most straight-forward paleohydrologic records recently published. These terrestrial proxies convey direct paleoenvironmental signals of effective precipitation and aquifer recharge. The two main proxies are temporal changes of terminal lake levels in the Dead Sea basin and periods of deposition or non-deposition of speleothems. Other records, such as stable isotopes, if interpreted correctly, correspond well with these two direct proxies. All the records consistently indicate that the last two glacial periods in the central Levant were generally wet and cool, while the last two interglacials were dry and warm, so more water was available for the ecosystem and thus hominins during glacial periods than during interglacials. Some proxies indicate that the higher precipitation/evaporation ratio during glacial periods involved higher precipitation rather than only reduced evaporation. Beyond the general mean glacial/interglacial climate suggested here, variations occurred at all temporal scales throughout glacial or interglacial periods. In the Sahara-Negev arid barrier, moister conditions occurred during Marine Isotope Stage (MIS) 6a-5e, when Anatomically Modern Humans apparently migrated out of Africa. We suggest that this migration, as well as the later Neanderthal expansion from Southeast Europe or the Anatolian plateau into the Levant during early MIS 4, could be facilitated by the observed major climatic variations. (C) 2010 Elsevier Ltd. All rights reserved.

Abstract  Uranium (U) concentrations in groundwater in several parts of the eastern San Joaquin Valley, California, have exceeded federal and state drinking water standards during the last 20 years. The San Joaquin Valley is located within the Central Valley of California and is one of the most productive agricultural areas in the world. Increased irrigation and pumping associated with agricultural and urban development during the last 100 years have changed the chemistry and magnitude of groundwater recharge, and increased the rate of downward groundwater movement. Strong correlations between U and bicarbonate suggest that U is leached from shallow sediments by high bicarbonate water, consistent with findings of previous work in Modesto, California. Summer irrigation of crops in agricultural areas and, to lesser extent, of landscape plants and grasses in urban areas, has increased Pco(2) concentrations in the soil zone and caused higher temperature and salinity of groundwater recharge. Coupled with groundwater pumping, this process, as evidenced by increasing bicarbonate concentrations in groundwater over the last 100 years, has caused shallow, young groundwater with high U concentrations to migrate to deeper parts of the groundwater system that are tapped by public- supply wells. Continued downward migration of U-affected groundwater and expansion of urban centers into agricultural areas will likely be associated with increased U concentrations in public-supply wells. The results from this study illustrate the potential long-term effects of groundwater development and irrigation-supported agriculture on water quality in arid and semiarid regions around the world.

Abstract  This article outlines the changes and underlying rationale for modifications to the histopathological evaluation of the nervous system during toxicology and carcinogenesis studies conducted by the National Toxicology Program (NTP). In the past, routine evaluation of the nervous system was mostly limited to three sections of brain, and occasionally the spinal cord and peripheral nerves. Factors such as the increasing occurrence of human neurological diseases and associated economical cost burden, the role of unidentified environmental stressors in neurodegenerative disorders, multiple therapeutic drug-induced neuropathies noted in human clinical trials, and the exponential use of environmental chemicals with unknown neurotoxic potential necessitate a more extensive evaluation of the nervous system. The NTP has modified its protocol to include examination of key anatomic subsites related to neurodegenerative diseases such as Parkinson’s disease. Modifications include four additional sections of the brain. Increasing the number of brain sections permits examination of a greater number of specific anatomic subsites with unique vulnerability. In addition, the spinal cord, peripheral nerves, trigeminal ganglion, and intestinal autonomic ganglia will be evaluated as needed. It is expected that this modified approach will increase the sensitivity of detecting neurotoxicants and neurocarcinogens important in human neurologic and neurodegenerative disorders.

Abstract  The mineralogy and evolution of Al and Mg in U mill tailings are poorly understood. Elemental analyses (ICP-MS) of both solid and aqueous phases show that precipitation of large masses of secondary Al and Mg mineral phases occurs throughout the raffinate neutralization process (pH 1-11) at the Key Lake U mill, Saskatchewan, Canada. Data from a suite of analytical methods (ICP-MS, EMPA, laboratory- and synchrotron-based XRD, ATR-IR, Raman, TEM, EDX, ED) and equilibrium thermodynamic modeling showed that nanoparticle-sized, spongy, porous, Mg-Al hydrotalcite is the dominant mineralogical control on Al and Mg in the neutralized raffinate (pH ≥ 6.7). The presence of this secondary Mg-Al hydrotalcite in mineral samples of both fresh and 15-year-old tailings indicates that the Mg-Al hydrotalcite is geochemically stable, even after >16 years in the oxic tailings body. Data shows an association between the Mg-Al hydrotalcite and both As and Ni and point to this Mg-Al hydrotalcite exerting a mineralogical control on the solubility of these contaminants.