Ionic Liquid and Supercritical Fluid Hyphenated Techniques for Dissolution and Separation of Lanthanides, Actinides, and Fission Products

This project is investigating techniques involving ionic liquids (IL) and supercritical (SC) fluids for dissolution and separation of lanthanides, actinides, and fission products. The research project consists of the following tasks: Study direct dissolution of lanthanide oxides, uranium dioxide and other actinide oxides in [bmin][Tf{sub 2}N] with TBP(HNO{sub 3}){sub 1.8}(H{sub 2}O){sub 0.6} and similar types of Lewis acid-Lewis base complexing agents; Measure distributions of dissolved metal species between the IL and the sc-CO{sub 2} phases under various temperature and pressure conditions; Investigate the chemistry of the dissolved metal species in both IL and sc-CO{sub 2} phases using spectroscopic and chemical methods; Evaluate potential applications of the new extraction techniques for nuclear waste management and for other projects. Supercritical carbon dioxide (sc-CO{sub 2}) and ionic liquids are considered green solvents for chemical reactions and separations. Above the critical point, CO{sub 2} has both gas- and liquid-like properties, making it capable of penetrating small pores of solids and dissolving organic compounds in the solid matrix. One application of sc-CO{sub 2} extraction technology is nuclear waste management. Ionic liquids are low-melting salts composed of an organic cation and an anion of various forms, with unique properties making them attractive replacements for the volatile organic solvents traditionally used in liquid-liquid extraction processes. One type of room temperature ionic liquid (RTIL) based on the 1-alkyl-3-methylimidazolium cation [bmin] with bis(trifluoromethylsulfonyl)imide anion [Tf{sub 2}N] is of particular interest for extraction of metal ions due to its water stability, relative low viscosity, high conductivity, and good electrochemical and thermal stability. Recent studies indicate that a coupled IL sc-CO{sub 2} extraction system can effectively transfer trivalent lanthanide and uranyl ions from nitric acid solutions. Advantages of this technique include operation at ambient temperature and pressure, selective extraction due to tunable sc-CO{sub 2} solvation strength, no IL loss during back-extraction, and no organic solvent introduced into the IL phase

Solution Effects on Cesium Complexation with Calixarene - Crown Ethers from Liquid to Supercritical Fluids

Supercritical fluid CO2 is an alternative solvent for extraction of metals. The solubility parameter of supercritical CO2 varies with density resembling that of liquid hexane at moderate pressures in the supercritical region to those of chlorinated solvents at very high pressures. By changing density of supercritical CO2, the solvation environment of a metal chelate system can vary continuously and resembles over a wide range of solvents. Thus, supercritical CO2 provides a unique system for studying solvation effects on metal chelation. This project is designed to investigate the solvation effects on cesium complexation with macrocyclic compounds including crown ethers and calixarene-crown ethers in CO2 from liquid to supercritical region at high pressures. A powerful spectroscopic technique for studying cesium chelation is nuclear magnetic resonance (NMR). Cesium has only one isotope, 133Cs, with a nuclear spin I = 7/2. Popov et al. used NMR to study cesium complexation with crown ethers and cryptand

Translation and Validation of the Chinese ICD-11 International Trauma Questionnaire (ITQ) for the Assessment of Posttraumatic Stress Disorder (PTSD) and Complex PTSD (CPTSD)

Background: Two stress-related disorders have been proposed for inclusion in the revised ICD-11: Posttraumatic Stress Disorder (PTSD) and Complex PTSD (CPTSD). The International Trauma Questionnaire (ITQ) is a bespoke measure of PTSD and CPTSD and has been widely used in English-speaking countries. Objective: The primary aim of this study was to develop a Chinese version of the ITQ and assess its content, construct, and concurrent validity. Methods: Six mental health practitioners and experts rated the Chinese translated and back-translated items to assess content validity. A sample of 423 Chinese young adults completed the ITQ, the WHO Adverse Childhood Experiences International Questionnaire, and the Hospital Anxiety and Depression Scale. Among them, 31 participants also completed the English and Chinese versions of the ITQ administered in random order at retest. Four alternative confirmatory factor analysis models were tested using data from participants who reported at least one adverse childhood experience (ACE; N = 314). Results: The Chinese ITQ received excellent ratings on relevance and appropriateness. Test–retest reliability and semantic equivalence across English and Chinese versions were acceptable. The correlated first-order six-factor model and a second-order two-factor (PTSD and DSO) both provided an acceptable model fit. The six ITQ symptoms clusters were all significantly correlated with anxiety, depression, and the number of ACEs. Conclusions: The Chinese ITQ generates scores with acceptable psychometric properties and provides evidence for including PTSD and CPTSD as separate diagnoses in ICD-11

DISSOLUTION OF METAL OXIDES AND SEPARATION OF URANIUM FROM LANTHANIDES AND ACTINIDES IN SUPERCRITICAL CARBON DIOXIDE

This paper investigates the feasibility of extracting and separating uranium from lanthanides and other actinides by using supercritical fluid carbon dioxide (sc-CO2) as a solvent modified with tri-n-butylphosphate (TBP) for the development of a counter current stripping technique, which would be a more efficient and environmentally benign technology for spent nuclear fuel reprocessing compared to traditional solvent extraction. Several actinides (U, Pu, and Np) and europium were extracted in sc-CO2 modified with TBP over a range of nitric acid concentrations and then the actinides were exposed to reducing and complexing agents to suppress their extractability. According to this study, uranium/europium and uranium/plutonium extraction and separation in sc-CO2 modified with TBP is successful at nitric acid concentrations of less than 6 M and at nitric acid concentrations of less than 3 M with acetohydroxamic acid or oxalic acid, respectively. A scheme for recycling uranium from spent nuclear fuel by using sc-CO2 and counter current stripping columns is presented

Solvent Effects on Cesium Complexation with Crown Ethers from Liquid to Supercritical Fluids

Nuclear magnetic resonance (NMR) techniques were used to study crown ether-water interactions in solvents of low dielectric constants such as chloroform and carbon tetrachloride. Water forms a 1:1 complex with a number of crown ethers including 12-crown-4, 15-crown-5, 18-crown-6, dicyclohexano-18=crown-6, dicyclohexano-24-crown 8, and dibenzl-24-crown-8 in chloroform. Among these crown ethers, the 18-crown-6-H2 complex has the largest equilibrium constant (K=545) and 97% of the crown is complexed to water in chloroform. Addition of carbon tetrachloride to chloroform lowers the equilibrium constants of the crown-water complexes. The partition coefficients of crown ethers (D=crown in water/crown in solvent) between water and organic solvent also vary with solvent composition

Selective Extraction of Uranium from Liquid or Supercritical Carbon Dioxide

Current liquid-liquid extraction processes used in recycling irradiated nuclear fuel rely on (1) strong nitric acid to dissolve uranium oxide fuel, and (2) the use of aliphatic hydrocarbons as a diluent in formulating the solvent used to extract uranium. The nitric acid dissolution process is not selective. It dissolves virtually the entire fuel meat which complicates the uranium extraction process. In addition, a solvent washing process is used to remove TBP degradation products, which adds complexity to the recycling plant and increases the overall plant footprint and cost. A liquid or supercritical carbon dioxide (l/sc -CO2) system was designed to mitigate these problems. Indeed, TBP nitric acid complexes are highly soluble in l/sc -CO2 and are capable of extracting uranium directly from UO2, UO3 and U3O8 powders. This eliminates the need for total acid dissolution of the irradiated fuel. Furthermore, since CO2 is easily recycled by evaporation at room temperature and pressure, it eliminates the complex solvent washing process. In this report, we demonstrate: (1) A reprocessing scheme starting with the selective extraction of uranium from solid uranium oxides into a TBP-HNO3 loaded Sc-CO2 phase, (2) Back extraction of uranium into an aqueous phase, and (3) Conversion of recovered purified uranium into uranium oxide. The purified uranium product from step 3 can be disposed of as low level waste, or mixed with enriched uranium for use in a reactor for another fuel cycle. After an introduction on the concept and properties of supercritical fluids, we first report the characterization of the different oxides used for this project. Our extraction system and our online monitoring capability using UV-Vis absorbance spectroscopy directly in sc-CO2 is then presented. Next, the uranium extraction efficiencies and kinetics is demonstrated for different oxides and under different physical and chemical conditions: l/sc -CO2 pressure and temperature, TBP/HNO3 complex used, reductant or complexant used for selectivity, and ionic liquids used as supportive media. To complete the extraction and recovery cycle, we then demonstrate uranium back extraction from the TBP loaded sc-CO2 phase into an aqueous phase and the characterization of the uranium complex formed at the end of this process. Another aspect of this project was to limit proliferation risks by either co-extracting uranium and plutonium, or by leaving plutonium behind by selectively extracting uranium. We report that the former is easily achieved, since plutonium is in the tetravalent or hexavalent oxidation state in the oxidizing environment created by the TBP-nitric acid complex, and is therefore co-extracted. The latter is more challenging, as a reductant or complexant to plutonium has to be used to selectively extract uranium. After undertaking experiments on different reducing or complexing systems (e.g., AcetoHydroxamic Acid (AHA), Fe(II), ascorbic acid), oxalic acid was chosen as it can complex tetravalent actinides (Pu, Np, Th) in the aqueous phase while allowing the extraction of hexavalent uranium in the sc-CO2 phase. Finally, we show results using an alternative media to commonly used aqueous phases: ionic liquids. We show the dissolution of uranium in ionic liquids and its extraction using sc-CO2 with and without the presence of AHA. The possible separation of trivalent actinides from uranium is also demonstrated in ionic liquids using neodymium as a surrogate and diglycolamides as the extractant

Lower pretreatment HBV DNA levels are associated with better off-treatment outcomes after nucleo(s)tide analogue withdrawal in patients with HBeAg-neegative chronic hepatitis B:A multicentre cohort study

Background &amp; Aims: Pretreatment predictors of finite nucleo(s)tide analogue (NUC) therapy remain elusive. We studied the association between pretreatment HBV DNA levels and outcomes after therapy cessation. Methods: Patients with chronic hepatitis B who were HBeAg negative at the start of NUC treatment were enrolled from sites in Asia and Europe. We studied the association between pretreatment HBV DNA levels and (1) clinical relapse (defined as HBV DNA &gt;2,000 IU/ml + alanine aminotransferase &gt;2 × the upper limit of normal or retreatment) and (2) HBsAg loss after NUC withdrawal. Results: We enrolled 757 patients, 88% Asian, 57% treated with entecavir, with a median duration of treatment of 159 (IQR 156–262) weeks. Mean pretreatment HBV DNA levels were 5.70 (SD 1.5) log IU/ml and were low (&lt;20,000 IU/ml) in 150 (20%) and high (&gt;20,000 IU/ml) in 607 (80%). The cumulative risk of clinical relapse at 144 weeks after therapy cessation was 22% among patients with pretreatment HBV DNA levels &lt;20,000 IU/ml vs. 60% among patients with pretreatment HBV DNA levels &gt;20,000 IU/ml, whereas the cumulative probabilities of HBsAg loss were 17.5% vs. 5% (p &lt;0.001). In multivariable analysis, pretreatment HBV DNA levels &lt;20,000 IU/ml were independently associated with a reduced likelihood of clinical relapse (adjusted hazard ratio 0.379, p &lt;0.001) and with an increased chance of HBsAg loss (adjusted hazard ratio 2.872, p &lt;0.001). Conclusions: Lower pretreatment HBV DNA levels are associated with a lower risk of clinical relapse and a higher chance of HBsAg loss after cessation of NUC therapy, independent of end-of-treatment viral antigen levels. Further studies are needed to confirm these findings in non-Asian populations. Impact and Implications: A subgroup of patients with chronic hepatitis B may not require retreatment after stopping antiviral therapy. In this study, comprising 757 patients with chronic hepatitis B from Europe and Asia, we found that higher viral load before initiation of treatment was a risk factor for relapse after stopping treatment. Patients with a low HBV DNA level before starting antiviral therapy had the lowest risk of relapse, and a high chance of HBsAg loss, after stopping treatment. These findings can help select patients for treatment withdrawal and guide intensity of off-treatment monitoring.</p

Elevated tumor and serum levels of the hypoxia-associated protein osteopontin are associated with prognosis for soft tissue sarcoma patients

<p>Abstract</p> <p>Background</p> <p>Osteopontin (OPN) overexpression is correlated with a poor prognosis for tumor patients. However, only a few studies investigated the prognostic impact of expression of OPN in soft tissue sarcomas (STS) yet.</p> <p>Methods</p> <p>This study is based on tumor and serum samples from 93 adult STS patients. We investigated OPN protein levels in serum (n = 86) and tumor tissue (n = 80) by ELISA and OPN mRNA levels in tumor tissue (n = 68) by quantitative real-time PCR.</p> <p>Results</p> <p>No correlation was found between OPN levels in serum and tumor tissue. Moreover, an elevated OPN protein level in the serum was significantly associated with clinical parameters such as higher stage (p = 0.004), higher grade (p = 0.003), subtype (p = 0.002) and larger tumor size (p = 0.03). OPN protein levels in the tumor tissue were associated with higher stage (p = 0.06), higher grade (p = 0.003), subtype (p = 0.07) and an increased rate of relapse (p = 0.02). In addition, using a Cox's proportional hazards regression model, we found that an elevated OPN protein level in the serum and tumor tissue extracts is a significant negative prognostic factor for patients with STS. The relative risks of tumor-related death were 2.2 (p < 0.05) and 3.7 (p = 0.01), respectively.</p> <p>Conclusion</p> <p>Our data suggest OPN protein in serum as well as in tumor tissue extracts is an important prognostic factor for soft tissue sarcoma patients.</p

HBV DNA and HBsAg Levels at 24 Weeks Off-Treatment Predict Clinical Relapse and HBsAg Loss in HBeAg-Negative Patients Who Discontinued Antiviral Therapy

Background &amp; Aims: Patients who discontinue nucleo(s)tide analogue therapy are at risk of viral rebound and severe hepatitis flares, necessitating intensive off-treatment follow-up. Methods: We studied the association between hepatitis B surface antigen (HBsAg) and hepatitis B virus (HBV) DNA levels at off-treatment follow-up week 24 (FU W24), with subsequent clinical relapse, and HBsAg loss in a multicenter cohort of hepatitis B e antigen (HBeAg)–negative patients with chronic hepatitis B who discontinued nucleo(s)tide analogue therapy. Results: We studied 475 patients, 82% Asian, and 55% treated with entecavir. Patients with higher HBV DNA levels at FU W24 had a higher risk of clinical relapse (hazard ratio [HR], 1.576; P &lt;.001) and a lower chance of HBsAg loss (HR, 0.454; P &lt;.001). Similarly, patients with higher HBsAg levels at FU W24 had a higher risk of clinical relapse (HR, 1.579; P &lt;.001) and a lower chance of HBsAg loss (HR, 0.263; P &lt;.001). A combination of both HBsAg &lt;100 IU/mL and HBV DNA &lt;100 IU/mL at FU W24 identified patients with excellent outcomes (9.9% clinical relapse and 58% HBsAg loss at 216 weeks of follow-up). Conversely, relapse rates were high and HBsAg loss rates negligible among patients with both HBsAg &gt;100 IU/mL and HBV DNA &gt;100 IU/mL (P &lt;.001). Conclusions: Among HBeAg-negative patients with chronic hepatitis B who discontinued antiviral therapy and who did not experience clinical relapse before FU W24, serum levels of HBV DNA and HBsAg at FU W24 can be used to predict subsequent clinical relapse and HBsAg clearance. A combination of HBsAg &lt;100 IU/mL with HBV DNA &lt;100 IU/mL identifies patients with a low risk of relapse and excellent chances of HBsAg loss and could potentially be used as an early surrogate end point for studies aiming at finite therapy in HBV.</p