Plutonium mobility and reactivity in a heterogeneous clay rock barrier accented by synchrotron-based microscopic chemical imaging.

The long-term safe disposal of radioactive waste corresponds to a challenging responsibility of present societies. Within deep geological waste disposal concepts, host rocks correspond to the ultimate safety barrier towards the environment. To assess the performance of such barriers over extended time scales, mechanistic information on the interaction between the radiotoxic, long-lived radionuclides like plutonium and the host rock is essential. Chemical imaging based on synchrotron microspectroscopic techniques was used to visualize undisturbed reactive transport patterns of Pu within pristine Opalinus Clay rock material. Pu+V is shown to be progressively reduced along its diffusion path to Pu+IV and Pu+III due to interaction with redox-active clay rock constituents. Experimental results and modeling emphasize the dominant role of electron-transfer reactions determining the mobility of Pu in reactive barrier systems. The effective migration velocity of Pu is controlled by the kinetic rates of the reduction to Pu+IV and Pu+III and the redox capacity of the involved electron donor pools. To advance our predictive capabilities further, an improved understanding of the nature and capacity of redox-active components of the reactive barrier material is fundamental. The findings represent an essential contribution to the evaluation of the long-term safety of potential nuclear waste repositories and have implications regarding the development of effective geological disposal strategies.

A sex-adjusted and age-adjusted genome screen for nested alcohol dependence diagnoses.

Alcohol dependence is a complex disorder with a substantial genetic contribution to susceptibility. The Collaborative Study on the Genetics of Alcoholism is a multi-site study whose purpose is to detect, localize, and characterize genes contributing to this susceptibility. Previous linkage analyses of the trait of alcohol dependence in Collaborative Study on the Genetics of Alcoholism have used affected sib-pair methods with a dichotomous phenotype definition. In contrast, the analysis in this paper uses a sex-adjusted and age-adjusted multiple threshold liability model. The use of such a model, in that it includes unaffected as well as as affected subjects and in that it utilizes the differential severity of a diagnosis scale, should heuristically be more powerful than a straight affected sib-pair analysis. Three regions of interest are found on chromosome 1 (lod 5.17), chromosome 4 (lod 3.46), and chromosome 8 (lod 4.31). The region on chromosome 1 near the marker D1S532 is in the region previously reported as linked to alcohol dependence and correlated phenotypes in this dataset. The region on chromosome 4 near the alcohol dehydrogenase gene cluster has been reported to be linked to alcohol dependence in other studies, as well as to the alcohol consumption phenotype 'Maximum Number of Drinks in a 24-Hour Period' in this dataset. The region on chromosome 8 near the marker D8S1988 is homologous to a section of rat chromosome 5 to which an alcohol consumption phenotype has been linked.

Complexation of uranium(VI) with protocatechuic acid-application of iterative transformation factor analysis to EXAFS spectroscopy.

The speciation of 1 mM uranium(VI) in carbonate-free aqueous solutions of 50 mM protocatechuic acid (PCA, 3,4-dihydroxybenzoic acid) was studied in the pH range of 4.0 to 6.8 using EXAFS spectroscopy. The uranium L(III)-edge EXAFS spectra were analyzed using a newly developed computer algorithm for iterative transformation factor analysis (FA). Two structural different uranium(VI) complexes were observed. The speciation in the pH range of 4.0 to 4.8 is dominated by a 1:2 or 1:3 uranium(VI)/PCA complex with bidentate coordination of the carboxyl group to the uranium(VI) moiety. Already at pH 4.6 significant amounts of a second species are formed. This uranium(VI) species contains two PCA ligands that are bound to the uranium via their neighboring phenolic hydroxyl groups under formation of five-member rings.

Linkage mapping of quantitative trait loci in humans: an overview.

In this article, we provide an overview of the different statistical procedures that have been developed for linkage mapping of quantitative trait loci. We outline the model assumptions, the data requirements and the underlying tests for linkage for the different methods.

Molecular and atomic analysis of uranium complexes formed by three eco-types of Acidithiobacillus ferrooxidans.

A combination of EXAFS, transmission electron microscopy and energy-dispersive X-ray was used to conduct a molecular and atomic analysis of the uranium complexes formed by Acidithiobacillus ferrooxidans. The results demonstrate that this bacterium accumulates uranium as phosphate compounds. We suggest that at toxic levels when the uranium enters the bacterial cells, A. ferrooxidans can detoxify and efflux this metal by a process in which its polyphosphate bodies are involved.

Integrating sibship data for mapping quantitative trait loci.

Sibship methods have been shown to be more powerful than traditional sib-pair methods in mapping quantative trait loci. We propose a statistical procedure which integrates data on sibships into a so-called 'contrast function', a natural extension of the classical squared sib-pair trait difference proposed by Haseman & Elston (1972). We also develop a combined mean and contrast function which provides more information on linkage compared to the contrast function. Our method is extended to multiple, epistatically interacting trait loci. Monte-Carlo simulations are included to compare the efficiencies of the proposed procedures with some currently used methods. An application of our proposed method is presented using data on alcohol dependence.

Comparison of 3190 alcohol-dependent individuals with and without suicide attempts.

INTRODUCTION: Suicidal behaviors are often seen in alcohol-dependent individuals. The aim of this study is to identify and confirm risk factors for suicide attempts in a large, family-based sample of alcoholics. METHODS: Semistructured, detailed interviews were administered to 3190 alcohol-dependent individuals as part of the Collaborative Study on the Genetics of Alcoholism (COGA). Information about suicidal behavior, socioeconomic characteristics, psychiatric comorbidity, substance use disorders, and characteristics of alcohol dependence were obtained from alcohol-dependent probands, controls, and their relatives. RESULTS: As determined by both univariate comparison and multivariate logistic regression analysis, alcohol-dependent individuals with a history of suicide attempts were found to have a significantly more severe course of alcohol dependence and a higher prevalence of both independent and substance-induced psychiatric disorders and other substance dependence. First-degree relatives of subjects with suicide attempts showed a significantly higher rate of suicide attempts, even after controlling for additional relevant diagnoses. CONCLUSION: These results support the hypothesis that alcohol-dependent individuals with a history of suicide attempts are more severely impaired. Screening and subsequent treatment of alcohol use disorder, psychiatric comorbidity, and substance use disorders among alcoholics may be crucial in preventing suicide attempts and completions.

Developmental sequence from disruptive behavior diagnosis to adolescent alcohol dependence.

OBJECTIVE: The authors sought to clinically describe the relationship of disruptive behavior disorders with both alcohol dependence and the use of a variety of substances. METHOD: The Child Semi-Structured Assessment for the Genetics of Alcoholism was used to collect data on 54 adolescents with a diagnosis of alcohol dependence. The frequency and age at onset of the disruptive behavior disorder diagnoses were examined as well as age at first use of alcohol, tobacco, marijuana, and other street drugs. RESULTS: Nearly three-quarters of the alcohol-dependent adolescents had at least one disruptive behavior disorder diagnosis. Attention deficit hyperactivity disorder (ADHD) typically occurred first, followed by conduct disorder. Substance use began with alcohol or tobacco, followed by marijuana and then other street drugs. Alcohol dependence began significantly later than the onset of either ADHD or conduct disorder and significantly later than the first use of tobacco. CONCLUSIONS: Disruptive behavior diagnoses, particularly conduct disorder, typically precede the initiation of use of a variety of substances that, in turn, precede the diagnosis of alcohol dependence in adolescents.

EXAFS as a tool for bond-length determination in the environment of heavy atoms.

Single crystal X-ray diffraction measurements are complicated in the presence of heavy atoms. In these cases the structure factors are mainly influenced by the heavy scatterers and the error in determination of atomic coordinates increases for light atoms. The difficulties grow if the unit cell dimensions or the space group symmetry remain uncertain. If the structure model is similar to the correct structure, it is difficult to find an independent criterion for the accuracy of the bond-length determination. We demonstrate that extended X-ray absorption fine structure (EXAFS) spectroscopy is a useful tool for the investigation of local bond lengths in the environment of heavy atoms.

Five-year clinical course associated with DSM-IV alcohol abuse or dependence in a large group of men and women.

OBJECTIVE: The prognostic validity of the DSM-IV diagnoses of alcohol abuse and alcohol dependence was evaluated by examining the 5-year clinical course associated with those diagnoses in a large group of predominantly blue-collar men and women. METHOD: Personal semistructured interviews were carried out 5 years after an initial evaluation with 1,346 (75%) of the approximately 1,800 men and women participating in the Collaborative Study on the Genetics of Alcoholism who were eligible for follow-up. RESULTS: About two-thirds of the 298 subjects with DSM-IV alcohol dependence at baseline maintained that diagnosis during the 5-year study period. Fifty-five percent of the 288 subjects with DSM-IV alcohol abuse at baseline continued to meet one or more of the 11 DSM-IV abuse/dependence criteria, and 3.5% went on to meet the criteria for dependence at follow-up. Among the 760 subjects with no alcohol diagnosis at baseline, 2.5% met the criteria for alcohol dependence and 12.8% for alcohol abuse at follow-up. Baseline characteristics that predicted the occurrence of any of the 11 DSM-IV abuse/dependence criteria during the 5-year interval included male gender, lack of marital stability, presence of several of the criteria for dependence, and history of illicit drug use. CONCLUSIONS: The data suggest that over 5 years the DSM-IV diagnosis of alcohol dependence predicts a chronic disorder with a relatively severe course, while DSM-IV alcohol abuse predicts a less persistent, milder disorder that does not usually progress to dependence.

Evidence for a locus on chromosome 1 that influences vulnerability to alcoholism and affective disorder.

OBJECTIVE: Depression (major depression or depressive syndrome) is more prevalent in alcoholic than in nonalcoholic subjects in families with multiple members with alcoholism studied as part of the Collaborative Study on the Genetics of Alcoholism (National Institute on Alcohol Abuse and Alcoholism). First-degree relatives of probands with comorbid alcoholism and depression have a higher prevalence of both disorders than relatives of probands with alcoholism alone, and both groups have a higher prevalence than the relatives of comparison subjects selected without regard to psychopathology. Data from the collaborative study were used to test three phenotypes (comorbid alcoholism and depression, alcoholism or depression, and depression) for genetic linkage. METHOD: Genome-wide sibling-pair linkage analyses were performed with the phenotypes comorbid alcoholism and depression, alcoholism or depression, and depression (major depression or depressive syndrome). Analyses were performed in two data sets (initial and replication data sets) from subject groups ascertained with identical criteria, as well as in the combined data set. RESULTS: Peak lod scores on chromosome 1 (near 120 centimorgan) for the alcoholism or depression phenotype were 5.12, 1.52, and 4.66 in the initial, replication, and combined data sets, respectively. The corresponding lod scores on chromosome 2 were 2.79, 0.20, and 3.26; on chromosome 6, they were 3.39, 0.00, and 0.92; and on chromosome 16, they were 3.13, 0.00, and 2.06. Lod scores on chromosome 2 for the comorbid alcoholism and depression phenotype in the three data sets were 0.00, 4.12, and 2.16, respectively. CONCLUSIONS: The results suggest that a gene or genes on chromosome 1 may predispose some individuals to alcoholism and others to depression (which may be alcohol induced). Loci on other chromosomes may also be of interest.

Risk domains associated with an adolescent alcohol dependence diagnosis.

AIMS: To determine the contribution of familial, interpersonal, academic and early substance use factors to relative risk for an alcohol dependence (AD) diagnosis in adolescents. METHODS: Information on 619 adolescents and their 390 sets of biological parents was obtained using the adolescent version of the Child Semi-Structured Assessment for the Genetics of Alcoholism (C-SSAGA) and the adult counterpart of this instrument, the Semi-Structured Assessment for the Genetics of Alcoholism (SSAGA). The C-SSAGA elicits a wide range of environmental, social, and psychiatric diagnostic information. Specific domain scale scores associated with an adolescent AD were computed, and generalized estimating equations (GEE) modeling was used to determine the odds ratio (relative risk) of the specified risk domains for an alcohol dependence diagnosis. FINDINGS: Risk factors for a DSM-III-R AD diagnosis included being at least 16 years of age, as well as negative parent-child interactions, school and personal-related difficulties (including the presence of an externalizing or internalizing DSM-III-R non-alcohol-related diagnosis), and early experimentations with a variety of substances. CONCLUSIONS: An array of familial, interpersonal, academic and early substance use factors were strongly associated with adolescent AD. Given the findings of this study, further research to determine temporal relationships that might influence the onset of adolescent alcohol dependence is warranted.

A genome-wide search for genes that relate to a low level of response to alcohol.

BACKGROUND: The low level of response (LR) to alcohol is genetically influenced in both humans and animals, and a low LR is a characteristic of offspring of alcoholics that has been reported to predict alcoholism 10 and 15 years later. The genes that contribute to a low LR have not yet been identified. METHODS: A 12-item questionnaire that measures LR, the Self Rating of the Effects of Alcohol (SRE) instrument, was filled out by 745 individuals from the Collaborative Study on the Genetics of Alcoholism (COGA) for whom genetic material was available. These subjects were genotyped by using 336 markers with an average heterozygosity of 0.74 and an average intermarker distance of 10.5 cM. Both quantitative and qualitative nonparametric, sib-pair analyses were carried out for the SRE measure related to early drinking experiences. RESULTS: Correlations of SRE scores across related individuals were significant and between 0.16 and 0.22 for most values, compared with nonsignificant correlations of 0.03 or less among unrelated individuals. Linkage analyses performed by using the FIRST 5 variables (first five times alcohol is consumed) identified four chromosomal regions with lod scores > or = 2.0 whose maximum was also near a marker. One of these chromosomal regions previously was linked to alcohol dependence in the COGA sample. CONCLUSIONS: These data document the familial nature of a low LR to alcohol as measured by the SRE and suggest several chromosomal regions that might contribute to the phenomenon.

A bootstrapped commingling analysis of platelet monoamine oxidase activity levels corrected for cigarette smoking.

Monoamine oxidase (MAO) activity levels have been suggested as a possible biological marker for alcohol dependence and abuse, as well as for schizophrenia and other psychiatric conditions. Using platelet MAO activities in the Collaborative Study on the Genetics of Alcoholism data set, we applied bootstrapping methods as a novel way to test for admixture in families. This bootstrapping involved resampling in family units and hypothesis testing of the resampled datasets for commingling in the distribution of MAO activity levels. Prior to commingling analysis, we used linear models to find covariates of greatest effect on MAO activity levels. While an alcoholism diagnosis was significant in men (n = 1151, P < 0.0001) and women (n = 1254, P = 0.0003), the effect lost significance after controlling for cigarette smoking, indicating alcoholism and smoking behavior to be highly confounded. When smoking histories were compared, former smokers had levels (mean = 7.1) closer to those who never smoked (mean = 7.0) than to current smokers (mean = 5.4). Furthermore, current daily smoking and time since smoking cessation were significantly related to MAO levels, indicating smoking probably has a direct effect on MAO levels, rather than the reverse. These results suggest that studies using MAO levels as a biological marker should consider smoking as an important covariate. Finally, admixture was found in MAO levels controlled for smoking and sex, possibly indicating a major genetic locus; this confirms previous evidence for admixture.

Markov chain Monte Carlo linkage analysis of complex quantitative phenotypes.

We report a Markov chain Monte Carlo analysis of the five simulated quantitative traits in Genetic Analysis Workshop 12 using the Loki software. Our objectives were to determine the efficacy of the Markov chain Monte Carlo method and to test a new scoring technique. Our initial blind analysis, on replicate 42 (the "best replicate") successfully detected four out of the five disease loci and found no false positives. A power analysis shows that the software could usually detect 4 of the 10 trait/gene combinations at an empirical point-wise p-value of 1.5 x 10(-4).

Do perchlorate and triflate anions bind to the uranyl cation in an acidic aqueous medium? A combined EXAFS and quantum mechanical investigation.

Structural properties of uranyl cations in acidic aqueous perchlorate and triflate solutions were investigated using uranium LIII -edge extended X-ray absorption fine-structure spectroscopy (EXAFS) in conjunction with quantum mechanical calculations of gas-phase model complexes. EXAFS spectra were measured in aqueous solutions of up to 10 M triflic and 11.5 M perchloric acid, as well as mixtures of perchloric acid and sodium perchlorate. In no case is the perchlorate anion coordinated to UO2(2+). The number of equatorial water molecules bound to UO2(2+) is always about five. In the case of the 10 M CF3SO3H solution, an inner-sphere complexation of the triflate is observed with a U-S radial distance of 3.62 Å. These results are in qualitative agreement with quantum mechanical calculations of model uranyl complexes, according to which the interaction energies of anions follow the order perchlorate

Genetics of event-related brain potentials in response to a semantic priming paradigm in families with a history of alcoholism.

Event-related brain potentials (ERPs) are altered in patients with a variety of psychiatric disorders and may represent quantitative correlates of disease liability that are more amenable to genetic analysis than disease status itself. Results of a genomewide linkage screen are presented for amplitude of the N4 and P3 components of the ERP, measured at 19 scalp locations in response to a semantic priming task for 604 individuals in 100 pedigrees ascertained as part of the Collaborative Study on the Genetics of Alcoholism. N4 and P3 amplitudes in response to three stimuli (nonwords, primed words [i.e., antonyms], and unprimed words) all showed significant heritabilities, the highest being.54. Both N4 and P3 showed significant genetic correlations across stimulus type at a given lead and across leads within a stimulus, indicating shared genetic influences among the traits. There were also substantial genetic correlations between the N4 and P3 amplitudes for a given lead, even across stimulus type. N4 amplitudes showed suggestive evidence of linkage in several chromosomal regions, and P3 amplitudes showed significant evidence of linkage to chromosome 5 and suggestive evidence of linkage to chromosome 4.