Tuning the Multiferroic Properties of BiFeO_{3} under Uniaxial Strain.

More than twenty years ago, multiferroic compounds combining in particular magnetism and ferroelectricity were rediscovered. Since then, BiFeO_{3} has emerged as the most outstanding multiferroic by combining at room temperature almost all the fundamental or applicative properties that may be desired: electroactive spin wave excitations called electromagnons, conductive domain walls, or a low band gap of interest for magnonic devices. All these properties have so far only been discontinuously strain engineered in thin films according to the lattice parameter imposed by the substrate. Here we explore the ferroelectricity and the dynamic magnetic response of BiFeO_{3} bulk under continuously tunable uniaxial strain. Using elasto-Raman spectroscopy, we show that the ferroelectric soft mode is strongly enhanced under tensile strain and driven by the volume preserving deformation at low strain. The magnonic response is entirely modified with low energy magnon modes being suppressed for tensile strain above pointing out a transition from a cycloid to an homogeneous magnetic state. Effective Hamiltonian calculations show that the ferroelectric and the antiferrodistortive modes compete in the tensile regime. In addition, the homogeneous antiferromagnetic state becomes more stable compared to the cycloidal state above a +2% tensile strain close to the experimental value. Finally, we reveal the ferroelectric and magnetic orders of BiFeO_{3} under uniaxial strain and how the tensile strain allows us to unlock and to modify in a differentiated way the polarization and the magnetic structure.

Progress in understanding the vulnerability of freshwater ecosystems.

The ability to collect and synthesize long-term environmental monitoring data is essential for the effective management of freshwater ecosystems. Progress has been made in assessment and monitoring approaches that have integrated routine monitoring programs into more holistic watershed-scale vulnerability assessments. While the concept of vulnerability assessment is well-defined for ecosystems, complementary and sometimes competing concepts of adaptive management, ecological integrity, and ecological condition complicate the communication of results to a broader audience. Here, we identify progress in freshwater assessments that can contribute to the identification and communication of freshwater vulnerability. We review novel methods that address common challenges associated with: 1) a lack of baseline information, 2) variability associated with a spatial context, and 3) the taxonomic sufficiency of biological indicators used to make inferences about ecological conditions. Innovation in methods and communication are discussed as a means to highlight meaningful cost-effective results that target policy towards heuristic ecosystem-management.

Molecular and organizational diversity intersect to generate functional synaptic heterogeneity within and between excitatory neuronal subtypes.

Synaptic heterogeneity is a hallmark of complex nervous systems that enables reliable and responsive communication in neural circuits. In this study, we investigated the contributions of voltage-gated calcium channels (VGCCs) to synaptic heterogeneity at two closely related Drosophila glutamatergic motor neurons, one low- and one high-Pr. We find that VGCC levels are highly predictive of heterogeneous release probability among individual active zones (AZs) of low- or high-Pr inputs, but not between neuronal subtypes. Underlying organizational differences in the AZ cytomatrix, VGCC composition, and a more compact arrangement of VGCCs alter the relationship between VGCC levels and Pr at AZs of low- vs. high -Pr inputs, explaining this apparent paradox. We further find that the CAST/ELKS AZ scaffolding protein Bruchpilot differentially regulates VGCC levels at low- and high-Pr AZs following acute glutamate receptor inhibition, indicating that synapse-specific organization also impacts adaptive plasticity. These findings reveal intersecting levels of molecular and spatial diversity with context-specific effects on heterogeneity in synaptic strength and plasticity.

Genetic Testing in Familial Hypercholesterolemia: Is It for Everyone?

PURPOSE OF REVIEW: Lipid measurements and genetic testing are the main diagnostic tools for FH screening that are available in many countries. A lipid profile is widely accessible, and genetic testing, although available worldwide, in some countries is only performed in a research context. Still FH is diagnosed late, showing lack of early screening programs worldwide. RECENT FINDINGS: Pediatric screening of FH was recently recognized by the European Commission Public Health Best Practice Portal as one on the best practices in non-communicable disease prevention. The early diagnosis of FH and the lowering of LDL-C values over lifespan can reduce the risk of coronary artery disease and offer health and socioeconomic gains. Current knowledge about FH shows that early detection through appropriate screening needs to become a priority in healthcare systems worldwide. Governmental programs for FH identification should be implemented to unify the diagnosis and increase patient identification.

Sexual dimorphism in Kinosternon scorpioides (Linnaeus, 1766) from the Brazilian Amazon.

The sexual dimorphism of the Kinosternon scorpioides was evaluated using two different techniques (linear and geometric morphometry) from images and linear measurements of the carapace and plastron of adults (male and female). Linear morphometry indicated that the height and width of carapace and plastron are statistically different between sexes, with females being wider and taller. In the evaluation of geometric morphometry, ANOVA demonstrated variation in the size of the plastron and the shape of the carapace and plastron, expressing a tendency in shape for each sex. Sexual dimorphism, therefore, is verified for this species, notably by the plastron. This study indicates an additional tool for the phenotypic knowledge of animals, contributing to the study of threatened populations.

Biochemical and hormonal parameters of goats kept in a controlled environment consuming water with different levels of salinity / [Parâmetros bioquímicos e hormonais de caprinos consumindo água com diferentes níveis de salinidade mantidos em ambiente controlado]

The objective of this work was to evaluate the biochemical and hormonal variables of Moxotó and Canindé goats submitted to two temperatures - 26.0±0.6 (thermoneutral) and 32.0±1.2°C (above thermal comfort zone) - and consuming water with three levels of salinity (1.0, 6.0 and 12.0 dSm-1). Thirty-six animals (18 of each breed) were used, with an average age of 5.0±0.6months and an average weight of 20.0±2.3kg, housed in metabolic cages inside a climate chamber. The animals were distributed in a completely randomized design with a 2 × 2 × 3 factorial scheme (2 breeds, 2 temperatures and 3 levels of salinity) and three replications. The glucose and urea had a significant effect (P>0.05) according to water salinity. Glucose, cholesterol, protein, albumin, globulin, aspartate aminotransferase and hormones (T4, T3 and cortisol) varied according to temperature (P<0.05). There was a significant effect of time on hormonal variables (P<0.05). Biochemical and hormonal variables changed according to temperature and day shift, so that metabolism was reduced in the animals under thermal stress and accelerated when animals were in the thermal comfort zone.(AU)

O objetivo do trabalho foi avaliar as variáveis bioquímicas e hormonais de caprinos das raças Moxotó e Canindé, submetidos a duas temperaturas (26,0±0,6ºC e 32,0±1,2ºC), termoneutra e acima da zona de conforto térmico, respectivamente), consumindo água com três níveis de salinidade (1,0, 6,0 e 12,0dSm-1), utilizando-se 36 animais (18 de cada raça), com idade média de 5,0±0,6 meses e peso médio de 20,0±2,3kg, alojados em gaiolas metabólicas no interior de uma câmara climática. Os animais foram distribuídos em um delineamento inteiramente ao acaso, com esquema fatorial de 2 x 2 x 3 (2 raças, 2 temperaturas e 3 níveis de salinidade) e três repetições. A glicose e a ureia apresentaram efeito significativo (P<0,05) em função da salinidade da água. Glicose, colesterol, proteína, albumina, globulina, AST e hormônios (T4, T3 e cortisol) variaram conforme as temperaturas (P<0,05). Observou-se efeito significativo do horário sobre as variáveis hormonais (P<0,05). As variáveis bioquímicas e hormonais sofrem alterações em função da temperatura e do turno do dia, de modo que o metabolismo é reduzido em animais sob estresse térmico e acelerado quando os animais encontram-se na zona de conforto térmico.(AU)

Assessment of ecological impairment of Arctic streams: Challenges and future directions.

As increased growth and development put pressure on freshwater systems in Arctic environments, there is a need to maintain a meaningful and feasible framework for monitoring water quality. A useful tool for monitoring the ecological health of aquatic systems is by means of the analysis and inferences made from benthic invertebrates in a biomonitoring approach. Biomonitoring of rivers and streams within the Arctic has been under-represented in research efforts. Here, we investigate an approach for monitoring biological impairment in Arctic streams from anthropogenic land use at two streams with different exposure to urban development in Iqaluit, Nunavut, Arctic Canada. Sites upstream of development, at midpoint locations, and at the mouth of each waterbody were sampled during 6 campaigns (2008, 2009, 2014, 2015, 2018, and 2019) to address spatial and temporal variability of the macroinvertebrate community. The influence of taxonomic resolution scaling was also examined in order to understand the sensitivity of macroinvertebrates as indicators in Arctic aquatic systems. We demonstrate that standard biological metrics were effective in indicating biological impairment downstream of sources of point-source pollutants. A mixed-design ANOVA for repeated measures also found strong interannual variability; however, we did not detect intra-annual variation from seasonal factors. When examining metrics at the highest taxonomic resolution possible, the sensitivity of metrics increased. Likewise, when trait-based metrics (α functional diversity) were applied to indicators identified at high taxonomic resolution, a significant difference was found between reference and impacted sites. Our results show that even though Arctic systems have lower diversity and constrained life-history characteristics compared to temperate ecosystems, biomonitoring is not only possible, but also equally effective in detecting trends from anthropogenic activities. Thus, biomonitoring approaches in Arctic environments are likely a useful means for providing rapid and cost-effective means of assessing future environmental impact.

Cannabidiol in the prelimbic cortex modulates the comorbid condition between the chronic neuropathic pain and depression-like behaviour in rats: The role of medial prefrontal cortex 5-HT1A and CB1 receptors.

The prelimbic division (PrL) of the medial prefrontal cortex (mPFC) is a cerebral division that is putatively implicated in the chronic pain and depression. We investigated the activity of PrL cortex neurons in Wistar rats that underwent chronic constriction injury (CCI) of sciatic nerve and were further subjected to the forced swimming (FS) test and mechanical allodynia (by von Frey test). The effect of blockade of synapses with cobalt chloride (CoCl2), and the treatment of the PrL cortex with cannabidiol (CBD), the CB1 receptor antagonist AM251 and the 5-HT1A receptor antagonist WAY-100635 were also investigated. Our results showed that CoCl2 decreased the time spent immobile during the FS test but did not alter mechanical allodynia. CBD (at 15, 30 and 60 nmol) in the PrL cortex also decreased the frequency and duration of immobility; however, only the dose of 30 nmol of CBD attenuated mechanical allodynia in rats with chronic NP. AM251 and WAY-100635 in the PrL cortex attenuated the antidepressive and analgesic effect caused by CBD but did not alter the immobility and the mechanical allodynia when administered alone. These data show that the PrL cortex is part of the neural substrate underlying the comorbidity between NP and depression. Also, the previous blockade of CB1 cannabinoid receptors and 5-HT1A serotonergic receptors in the PrL cortex attenuated the antidepressive and analgesics effect of the CBD. They also suggest that CBD could be a potential medicine for the treatment of depressive and pain symptoms in patients with chronic NP/depression comorbidity.

How has COVID-19 affected the treatment of osteoporosis? An IOF-NOF-ESCEO global survey.

The effects of COVID-19 have the potential to impact on the management of chronic diseases including osteoporosis. A global survey has demonstrated that these impacts include an increase in telemedicine consultations, delays in DXA scanning, interruptions in the supply of medications and reductions in parenteral medication delivery. INTRODUCTION: The COVID-19 pandemic has had profound effects on the health of the global population both directly, via the sequelae of the infection, and indirectly, including the relative neglect of chronic disease management. Together the International Osteoporosis Foundation and National Osteoporosis Foundation sought to ascertain the impact on osteoporosis management. METHODS: Questionnaires were electronically circulated to a sample of members of both learned bodies and included information regarding the location and specialty of respondents, current extent of face to face consultations, alterations in osteoporosis risk assessment, telemedicine experience, alterations to medication ascertainment and delivery and electronic health record (EHR) utilisation. Responses were collected, quantitative data analysed, and qualitative data assessed for recurring themes. RESULTS: Responses were received from 209 healthcare workers from 53 countries, including 28% from Europe, 24% from North America, 19% from the Asia Pacific region, 17% from the Middle East and 12% from Latin America. Most respondents were physicians (85%) with physician assistants, physical therapists and nurses/nurse practitioners represented in the sample. The main three specialties represented included rheumatology (40%), endocrinology (22%) and orthopaedics (15%). In terms of the type of patient contact, 33% of respondents conducted telephone consultations and 21% video consultations. Bone mineral density assessment by dual-energy X-ray absorptiometry (DXA) usage was affected with only 29% able to obtain a scan as recommended. The majority of clinicians (60%) had systems in place to identify patients receiving parenteral medication, and 43% of clinicians reported difficulty in arranging appropriate osteoporosis medications during the COVID-19 crisis. CONCLUSIONS: To conclude through surveying a global sample of osteoporosis healthcare professionals, we have observed an increase in telemedicine consultations, delays in DXA scanning, interrupted supply of medications and reductions in parenteral medication delivery.

Indomethacin attenuates mechanical allodynia during the organization but not the maintenance of the peripheral neuropathic pain induced by nervus ischiadicus chronic constriction injury.

The neurochemical mechanisms underlying neuropathic pain (NP) are related to peripheral and central sensitization caused by the release of inflammatory mediators in the peripheral damaged tissue and ectopic discharges from the injured nerve, leading to a hyperexcitable state of spinal dorsal horn neurons. The aim of this work was to clarify the role played by cyclooxygenase (COX) in the lesioned peripheral nerve in the development and maintenance of NP by evaluating at which moment the non-steroidal anti-inflammatory drug indomethacin, a non-selective COX inhibitor, attenuated mechanical allodynia after placing one loose ligature around the nervus ischiadicus, an adaptation of Bennett and Xie's model in rodents. NP was induced in male Wistar rats by subjecting them to chronic constriction injury (CCI) of the nervus ischiadicus, placing one loose ligature around the peripheral nerve, and a sham surgery (without CCI) was used as control. Indomethacin (2 mg/kg) or vehicle was intraperitoneally and acutely administered in each group of rats and at different time windows (1, 2, 4, 7, 14, 21, and 28 days) after the CCI or sham surgical procedures, followed by von Frey's test for 30 min. The data showed that indomethacin decreased the mechanical allodynia threshold of rats on the first, second, and fourth days after CCI (P<0.05). These findings suggested that inflammatory mechanisms are involved in the induction of NP and that COX-1 and COX-2 are involved in the induction but not in the maintenance of NP.

Genotype effects on energy and protein requirements in growing male goats.

Goat genotype may alter the net energy and protein requirements for maintenance (NEm and NPm, respectively) and weight gain (NEg and NPg).This study was designed to investigate and quantify the effect of goat type on NEm, NPm, NEg and NPg, and quantify the net requirements for energy and protein for dairy, meat and indigenous growing male goats. For that, comparative slaughter studies were gathered and a meta-analytical approach was used. Two distinct databases were organized: one composed of 233 individual records from 11 studies of meat (n = 81), dairy (n = 97) and indigenous (n = 55) growing male goats weighing from 4.50 to 51.0 kg, to depict NEm and NPm; and another database composed of 239 individual records from nine studies of meat (n = 87), dairy (n = 97) and indigenous (n = 55) growing male goats weighing from 4.30 to 51.0 kg, to depict NEg and NPg. Our findings showed that NEm of meat goats was 8.5% greater (336 ± 10.8 kJ/kg0.75 of empty BW; EBW) than dairy and indigenous goats (310 ± 8.20 kJ/kg0.75 EBW; P < 0.05). Whereas, NPm was not affected by goat type (1.92 ± 0.239 g/kg EBW; P = 0.91). The NPg was 185.1 ± 1.82 g/kg of EBW gain for goats weighing 5 kg BW and 192.5 ± 4.33 g/kg of EBW gain for goats weighing 45 kg BW, and thus did not change across goat type (P = 0.12). On the other hand, NEg increased from 7.29 ± 0.191 to 11.9 ± 0.386 MJ/kg of EBW in male dairy goats, and from 7.32 ± 0.144 to 15.7 ± 0.537 MJ/kg of EBW in meat and indigenous growing male goats weighing between 5 and 45 kg BW. When body protein was used as a predictor in the allometric equation instead of EBW seeking to account for the degree of maturity, goat type differences disappeared; however, this predictor showed a high variation among individuals. In conclusion, energy and protein requirements for gain in distinct goat types reflect on body composition differences. Future research should focus on better understanding the maturity degree and its consequences in the energy requirement of growing male goats and better depict the goat type effect on it, as well as on the efficiency of utilization.

Indomethacin attenuates mechanical allodynia during the organization but not the maintenance of the peripheral neuropathic pain induced by nervus ischiadicus chronic constriction injury

The neurochemical mechanisms underlying neuropathic pain (NP) are related to peripheral and central sensitization caused by the release of inflammatory mediators in the peripheral damaged tissue and ectopic discharges from the injured nerve, leading to a hyperexcitable state of spinal dorsal horn neurons. The aim of this work was to clarify the role played by cyclooxygenase (COX) in the lesioned peripheral nerve in the development and maintenance of NP by evaluating at which moment the non-steroidal anti-inflammatory drug indomethacin, a non-selective COX inhibitor, attenuated mechanical allodynia after placing one loose ligature around the nervus ischiadicus, an adaptation of Bennett and Xie's model in rodents. NP was induced in male Wistar rats by subjecting them to chronic constriction injury (CCI) of the nervus ischiadicus, placing one loose ligature around the peripheral nerve, and a sham surgery (without CCI) was used as control. Indomethacin (2 mg/kg) or vehicle was intraperitoneally and acutely administered in each group of rats and at different time windows (1, 2, 4, 7, 14, 21, and 28 days) after the CCI or sham surgical procedures, followed by von Frey's test for 30 min. The data showed that indomethacin decreased the mechanical allodynia threshold of rats on the first, second, and fourth days after CCI (P<0.05). These findings suggested that inflammatory mechanisms are involved in the induction of NP and that COX-1 and COX-2 are involved in the induction but not in the maintenance of NP.

Age-dependent hepatic alterations induced by a high-fat high-fructose diet.

OBJECTIVE: The present study aimed to evaluate and clarify how the age at which the intake of a high-fat and high-fructose diet begins can affect animals' livers. METHODS: Thirty-eight male wistar rats aged 6 and 12 weeks were fed a high-fat and high-fructose diet for 13 weeks. Inflammatory cytokines, hepatic glycogen, serum and hepatic triacylglycerol and pAkt protein content in the liver were assessed. Percentage of weight gained, and visceral adiposity were also evaluated. RESULTS: Young animal presented increased hepatic triacylglycerol and decreased glycogen, while adult animals had no significant alterations regarding its contents. IL6 and IL10 to IL6 ratio were also altered in young animals exposed to HFHF, while adult animals fed with HFHF had only increases in TNF-α. Both groups which received HFHF had increased serum triacylglycerol and visceral adiposity. However, only young animals gained more relative weight and had greater final body weight, gains which were related to alterations found in hepatic triacylglycerol and glycogen. CONCLUSION: Age of which consumption begins interferes in how the liver deals with an excess of nutrient and subsequent proinflammatory stimulation, leading to different phenotypes.

Analysis of Defense-Related Gene Expression in Citrus Hybrids Infected by Xylella fastidiosa.

Resistance to Xylella fastidiosa was evaluated in 264 hybrids of crosses between Murcott tangor (Citrus reticulata × Citrus sinensis) and Pera sweet orange (C. sinensis) under field conditions. Uninfected hybrids were grafted with buds collected from Pera sweet orange plants infected with X. fastidiosa, forming a plant with two scions (i.e., hybrid branches and Pera sweet orange branches). From these plants, we chose 10 genotypes with three biological replicates. We evaluated gene expression, bacterial multiplication, and citrus variegated chlorosis (CVC) symptom development in both scions. X. fastidiosa was not detected in most hybrid scions and none showed disease symptoms. In contrast, all Pera sweet orange scions were infected with X. fastidiosa and expressed symptoms of CVC. We quantified the expression of 12 defense-related genes by qPCR comparing resistant to susceptible scions. We suggest that some of these genes are involved in resistance of the hybrids to X. fastidiosa, since their expression was significantly higher in the resistant hybrid scions than in tolerant hybrids and scions originated from CVC symptomatic Pera sweet orange buds. However, we note that these data should be interpreted carefully, as the plant genotypes tested are related but necessarily distinct (hybrids of C. reticulata and C. sinensis, in relation to a C. sinensis control). A principal component analysis revealed a relationship between the expression of these genes and hybrid scions, and between scions that originated from infected buds and the presence of the bacteria and plant symptoms. Multiyear field trials are necessary to develop plant resistance to X. fastidiosa. While the experimental design used here had limitations, it allowed us to identify a set of genes potentially involved in Citrus sp. resistance to this pathogen. Future work on the role of these genes in plant defenses to X. fastidiosa infection is necessary to confirm their importance in the displayed resistance phenotype.

Net mineral requirements for the growth and maintenance of Somali lambs.

Minerals are limiting factors in animal production, and the knowledge of mineral requirements for livestock is crucial to the success of a commercial enterprise. Hair sheep may have different mineral requirements than those presents by the international committees. A study was carried to evaluate the net calcium (Ca), phosphorus (P), magnesium (Mg), sodium (Na), potassium (K), zinc (Zn), iron (Fe), manganese (Mn) and copper (Cu) requirements for the growth and maintenance of Brazilian Somali lambs. A total of 48 hair lambs (13.5±1.8 kg) aged 60±15 days were allocated to individual pens. Eight animals were slaughtered at the beginning of the experiment to serve as a reference group to estimate initial empty BW (EBW) and initial body composition. The remaining lambs (n=40) were assigned to a completely randomized design with eight replications in five levels of metabolizable energy (ME; 4.93, 8.65, 9.41, 10.12 and 11.24 MJ/kg DM). When the lambs of a given treatment reached an average BW of 28 kg, they were slaughtered. Initial body composition was used to calculate the retention of minerals. Mineral body composition was fit using a logarithmic equation in the form of a nonlinear model. The maintenance requirements were estimated from regressions of mineral retention in the empty body on mineral intake. The body mineral concentration decreased in lambs with a BW ranging from 15 to 30 kg. The net mineral requirements (100 g/day of average daily gain (ADG)) decreased from 0.52 to 0.51 g for Ca, 0.28 to 0.23 g for P, 0.02 to 0.02 g for Mg, 0.09 to 0.08 g for Na, 0.11 to 0.09 g for K, 1.30 to 1.08 mg for Zn, 3.77 to 3.22 mg for Fe, 0.08 to 0.06 mg for Mn and 0.09 to 0.08 mg for Cu when BW increased from 15 to 30 kg. The daily net requirements for maintenance per kilogram of BW were 30.13 mg of Ca, 27.58 mg of P, 1.26 mg of Mg, 4.12 mg of Na, 8.11 mg of K, 0.133 mg of Zn, 0.271 mg of Fe, 0.002 mg of Mn and 0.014 mg of Cu. The results of this study indicate that the net mineral requirements for weight gain and maintenance in Brazilian Somali lambs are different than the values that are commonly recommended by the main evaluation systems for feed and nutritional requirements for sheep. These results for the nutritional requirements of minerals may help to optimize mineral supply for hair sheep.

Biomass burning and carbon monoxide patterns in Brazil during the extreme drought years of 2005, 2010, and 2015.

In the 21st century, severe droughts associated with climate change will increase biomass burning (BB) in Brazil caused by the human activities. Recent droughts, especially in 2005, 2010, and 2015, caused strong socioeconomic and environmental impacts. The 2015 drought considered the most severe since 1901, surpassed the 2005 and 2010 events in respect to area and duration. Herein, based on satellite data, the 2005, 2010 and 2015 drought impacts on wildfire episodes and carbon monoxide (CO) variability during the dry and the dry-to-wet transition seasons were examined. The BB occurrences in the dry season were fewer during 2015 than during 2005 (-44%) and 2010 (-47%). Contrasting, the BB events in the dry-to-wet transition season, were higher during 2015 than during 2005 (+192%) and 2010 (+332%). The BB outbreaks were concentrated in the southern and southwestern Amazon during 2005, in the Cerrado region during 2010, and mainly in the central and northern Amazon during 2015, an area normally with few fires. The CO concentration showed positive variations (up to +30%) occurred in the southern Amazon and central Brazil during the 2005 and 2010 dry seasons, and north of 20 °S during the 2015-2016 dry-to-wet transition season. The BB outbreaks and the CO emissions showed a considerable spatiotemporal variability among the droughts of 2005, 2010, and 2016, first of them driven by local conditions in the tropical North Atlantic (TNA), characterized by warm than normal sea surface waters and the other two by the El Niño occurrences.

Influence of soil conditions on the distribution coefficients of 226Ra in natural soils.

In order to clarify some of the assumptions and approximations about the use of the distribution coefficient Kd for 226Ra in soils, a systematic study has been performed using centrifugation to extract the soil solution. The separated fractions of the soil solution have different kinetics with respect to the sorption process in the soil, which may in turn condition the final chemical composition and even the speciation of the radionuclides in solution. In the experimental design of this study three factors were considered: the moisture level in the incubation process, incubation time and the speed of centrifugation. Also, three levels were chosen for each factor. In order to analyze the influence of the structural characteristics of the soil, this study was performed with three textural fractions: coarse sand, fine sand, and silt and clay, obtained from an only soil. Also, the soil was naturally enriched with radionuclides of the 238U series. An analysis of variance (ANOVA) was performed in order to assess the influence of the factors studied on the distribution coefficient of 226Ra. The results indicate that different behaviors can be observed depending on the structural characteristic of the soil. In the case of particle size, the soil with the largest grain size showed that the incubation process parameters influence the equilibrium level achieved, while in the case of the smallest edaphic particles, radium is not homogeneously distributed in the soil solution and the Kd value is dependent on the speed of centrifugation.