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2021 ◽  
Vol 84 (5) ◽  
pp. 473-482
Author(s):  
Rajmund S. Dybczyński ◽  
Krzysztof Kulisa

AbstractThe possibility of rare earth elements (REE) separation by ion interaction chromatography (IIC) employing their complexes with diglycolic acid (ODA) in anion exchange mode has been studied theoretically and experimentally. Calculations, assuming that only trivalent complex is significantly uptaken by the stationary phase, indicated that at at pH 4–6, the retention in the lanthanide series should increase from La to the Tb–Dy–Ho region with yttrium showing apparent atomic number (App.At.No.) of 67½ and then decrease with further increase of atomic number. Chromatographic experiments in the system: Column: Eternity C18—mobile phase 5 mM ODA/8.6 mM TBAOH/0.6 mM HNO3; pH 4.60 confirmed theoretically predictions. It was found that scandium at pH ≥ 4.0 elutes in front of the whole REE group but at low pH enters the region of light lanthanides. The non-monotonical change of affinity of the REE with the increase of atomic number results in quite unusual order of elution of REE namely: Sc < La < Ce < Lu < Pr < Yb < Nd < Tm < Sm < Eu < Er≈Y < Gd < Ho < Tb≈Dy.


2020 ◽  
Vol 12 (17) ◽  
pp. 7130
Author(s):  
Levonas Manusadžianas ◽  
Rimantas Vitkus ◽  
Brigita Gylytė ◽  
Reda Cimmperman ◽  
Mindaugas Džiugelis ◽  
...  

Due to unique chemical properties, rare earth elements (REEs) are increasingly used in versatile technological applications. They are considered emerging environmental contaminants, since they become mobile instead of being bound in rocks. At present, the information on REE effects to aquatic biota is scarce and contradictory. This study aims to explore the ecotoxicity of 11 lanthanides (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Er, and Lu) and yttrium (Y) to charophyte algae Nitellopsis obtusa and microcrustaceans Thamnocephalus platyurus. Median lethal concentrations (LC50) were assessed in characean cells at 8, 12, 16, 20, and 24 days of exposure, and 24-h LC50s were determined in shrimps. According to the EU−Directive 93/67/EEC hazard classification scheme and 24-day LC50 values generated for N. obtusa, REE effects were assigned from “harmful” to “very toxic” (Gd), while 24-h LC50s for T. platyurus were classified as “harmful” or “toxic” (based on nominal concentrations) and as “toxic” or “very toxic” (based on REE free ion concentrations calculated with CHEAQS Next software). The data obtained for algae showed correlations with the REE atomic numbers (r = −0.68, p < 0.05) and ionic radii (r = 0.65, p < 0.05) at the most extended 24-day exposure only. The analysis of the trends of concentration−response (c–r) curves obtained at increasing exposure durations (8–24 days), alongside the 24-day LC50s ranging within almost two orders of magnitude, allowed a more-toxic heavy REE group to be distinguished, and somewhat different modes REE actions to be envisioned for N. obtusa.


10.37236/8832 ◽  
2020 ◽  
Vol 27 (2) ◽  
Author(s):  
Yongli Zhang ◽  
Shenglin Zhou

This paper  determines all  pairs $(\mathcal{D},G)$ where $\mathcal{D}$ is a non-symmetric 2-$(v,k,\lambda)$ design   with $(r,\lambda)=1$ and  $G$ is  the  almost simple flag-transitive automorphism group of $\mathcal{D}$ with  an exceptional  socle of Lie type. We prove that if $T\trianglelefteq G\leq Aut(T)$ where $T$ is an exceptional group of Lie type, then $T$ must be the Ree group or Suzuki group, and there are five classes of designs $\mathcal{D}$.


2020 ◽  
Vol 79 (OCE2) ◽  
Author(s):  
Fathimath Naseer ◽  
Ruth Price ◽  
Adele McElroy ◽  
Carel Le Roux ◽  
Tamsyn Redpath ◽  
...  

AbstractBariatric surgery, including Gastric Bypass (GBP) Surgery, is the most efficient modality to manage severe obesity. Resting Energy Expenditure (REE) is an area of interest in the context of weight loss (WL) as it has been postulated to be an independent predictor of WL success following GBP. As such, the aim of this study is to investigate the impact of REE on WL following GBP. 31 GBP patients (77.4% females BMI 45.5 ± 7.0kg/m2 ; 47.3 ± 11.6y) and 32 weight-stable controls (46.9% females; BMI 27.0 ± 4.6kg/m2 ; 41.1 ± 13.5y) were assessed at one-month pre-surgery and at 3 and 12-months post-surgery. Fat mass (FM) and fat-free mass (FFM) were measured using dual energy X-ray absorptiometry (Lunar iDXA, GE Healthcare). REE was measured under standardised conditions using indirect calorimetry (ECAL, Metabolic Health Solutions). Statistical analyses were performed with SPSS v24.0, Armonk, NY. Multiple regression analysis showed that FM (P = 0.001), FFM (P < 0.0001) and gender (P = 0.012) significantly predicted the interindividual variability in REE. Total body weight (TBW) was removed from the model due to collinearity. Adjusted-REE values were then generated using the above predictor variables. Low-REE and high-REE groups were created using within-group adjusted-REE split. At both follow-ups (3- and 12-months post-surgery), patients had a greater reduction in TBW, FM, FFM, measured-REE and adjusted-REE values compared with controls (P < 0.0001). There was also no significant difference between measured and adjusted-REE values at all time-points (P > 0.05). Patients with high REEs at baseline lost more TBW than those in the low-REE group at 3-months post-surgery (-24.9 ± 6.5 kg vs. -16.6 ± 7.0 kg; P = 0.005) and 12-months post-surgery (-41.3 ± 12.5 kg vs. -25.8 ± 10.4.0 kg; P = 0.003). There was no significant difference in mean TBW changes for controls in the low-and high-REE groups at both follow-ups. Patients with high REEs at 3-months post-surgery did not lose more TBW than those in the low-REE group at 12-months post-surgery (-30.1 ± 12.8 kg vs. -38.6 ± 14.4 kg; P = 0.155). Similarly, there was no difference in mean TBW reduction between controls in the low- and high-REE groups (P = 0.115). Thus while patients with a high adjusted-REE value at baseline (> 9746.6kJ/day) lost more weight at 3- and 12-months post-GBP, it is plausible that from the third to the 12th month post-surgery, other key drivers of weight loss, particularly the reduction in energy intake are more important in predicting WL. Further research with a larger sample size is required to increase the chances of detecting a true effect.


EKSPLORIUM ◽  
2019 ◽  
Vol 40 (2) ◽  
pp. 99
Author(s):  
Sari Hasnah Dewi ◽  
Wisnu Ari Adi ◽  
Suyanti Suyanti

ABSTRAKPotensi logam tanah jarang (LTJ) di Indonesia sangat besar, terutama yang berasal dari mineral monasit. Monasit merupakan gabungan unsur LTJ-U/Th-fosfat yang berkaitan dengan endapan timah dan unsur-unsur radioaktif. Melalui program BATAN incorporated mineral monasit diolah menjadi bahan yang lebih benilai jual secara ekonomi. Lantanum (La) adalah logam yang termasuk dalam kelompok logam tanah jarang yang memiliki sifat-sifat unggul sebagai pigmen dan sebagai penyerap gelombang elektromagnetik. Tujuan penelitian ini adalah memperoleh informasi pengaruh pemanasan tinggi terhadap produk pilot plant pengolahan logam tanah jarang hidroksida (RE(OH)3) dari monasit, khususnya produk La2(C2O4)3 untuk pembuatan Certified Reference Material (CRM) La2O3. Bahan yang telah ditimbang dikalsinasi pada combustion boat dengan menggunakan furnace pada suhu pemanasan 1.000 OC dan 1.300 OC. Dekomposisi termal dianalisis dengan menggunakan Thermogravimetric analysis (TGA). Formasi fasa bahan dianalisis dengan menggunakan teknik X-Ray Diffraction (XRD). Hasil analisis XRD menunjukkan hasil akhir fasa bahan berubah menjadi La2O3 sebesar 28,76% dan La(OH)3 sebesar 71,24%.ABSTRACTRare earth elements (REE) in Indonesia have great potency, mainly from monazite mineral. Monazite is a combination of REE-U/Th-phosphate elements which is associated with tin deposit and radioactive elements. Through BATAN incorporated program, monazite mineral is processed to become more economically valuable materials. Lanthanum (La) is a metal element, part of REE group, which has excellent properties for pigment and electromagnetic absorber. The purpose of this study is to obtain information related to the effect of calcination in high temperature on the product of monazite’s REE hydroxide (RE(OH)3) processing pilot plant, specific on La2(C4O4)3 for Certified Reference Material (CRM) La­2O3 making. The weighed material is calcined on combustion boat by using a furnace at heating temperature of 1,000 OC and 1,300 OC. Thermal decomposition is analyzed by using Thermogravimetric analysis (TGA). Material phase formation is analyzed by using X-Ray Diffraction (XRD) method. XRD analysis shows the material in final phase has been transform to 28.76 % La2O3 and 71.24 % La(OH)3.


2019 ◽  
Vol 19 (1) ◽  
pp. 20-31
Author(s):  
Xiang He ◽  
Xufeng He ◽  
Ping Xu ◽  
Lili Yang ◽  
Xin Ma ◽  
...  

Background:Radix Euphorbiae Ebracteolatae (REE) was recently reported to be significantly superior to vitamin A acid ointment in treating multiple plantar warts. However, the effects of REE on HPV18 remain unclear. Therefore, the current study aimed to investigate the effects of REE on the proliferation of HPV18, and explore possible molecular mechanisms underlying the effects.Methods:HFK and HFK-HPV18 were treated with water-extracted single or compound REE, ethanol-extracted single or compound REE, TNF-α and IFN for 3 days, respectively. In addition, the organotypic rafts containing HFK-HPV18 and HFK were treated with REE, IFN and TNF-α for 7 days, respectively. Cell proliferation rates were measured with Brdu. mRNA expression of E6, L1, p53 and Rb was detected by qPCR. Protein expression of p53, Rb and L1 was detected by Western blot.Results:Compared to HFK group, HFK-HPV18 group had significantly higher expression of E6 and L1. Compared to the control group, HFK-HPV18 treated with REE, TNF-α and IFN displayed significantly lower proliferation rates. The mRNA expression of E6 was markedly lower, and mRNA expression of p53 and Rb was significantly higher after treatment of REE in HFK-HPV18 or in organotypic rafts containing HFK-HPV18. Treatment with REE markedly increased the protein expression of p53 and Rb, and decreased the protein expression of L1 in HFK-HPV18 or in organotypic rafts containing HFK-HPV18. Among all formula of REE, the inhibition of proliferation rates and expression of E6 and L1, and the increase in expression of p53 and Rb in HFK-HPV18 was highest in ethanol-extracted compound REE group.Conclusions:The proliferation rates are significantly lower in HFK-HPV18 treated with REE. The expression of E6 and L1 is markedly lower, and expression of p53 and Rb is significantly higher after REE treatment in HFK-HPV18 or organotypic rafts containing HFK-HPV18. Among all formula of REE, ethanol-extracted compound REE displays the highest protection against HPV18.


2018 ◽  
Vol 59 (3) ◽  
pp. 271-276
Author(s):  
 Asboei Alireza K. ◽  
Amiri Seyed S. S.
Keyword(s):  
Group 2 ◽  

10.37236/5510 ◽  
2016 ◽  
Vol 23 (1) ◽  
Author(s):  
Luke Morgan ◽  
Tomasz Popiel

Let $G$ be a collineation group of a thick finite generalised hexagon or generalised octagon $\Gamma$. If $G$ acts primitively on the points of $\Gamma$, then a recent result of Bamberg et al. shows that $G$ must be an almost simple group of Lie type. We show that, furthermore, the minimal normal subgroup $S$ of $G$ cannot be a Suzuki group or a Ree group of type $^2\mathrm{G}_2$, and that if $S$ is a Ree group of type $^2\mathrm{F}_4$, then $\Gamma$ is (up to point-line duality) the classical Ree-Tits generalised octagon.


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