623 research outputs found

    Spontaneous Chelation-Driven Reduction of the Neptunyl Cation in Aqueous Solution.

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    Octadentate hydroxypyridinone (HOPO) and catecholamide (CAM) siderophore analogues are known to be efficacious chelators of the actinide cations, and these ligands are also capable of facilitating both activation and reduction of actinyl species. Utilizing X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) spectroscopies, as well as cyclic voltammetry measurements, herein, we elucidate chelation-based mechanisms for driving reactivity and initiating redox processes in a family of neptunyl-HOPO and CAM complexes. Based on the selected chelator, the ability to control the oxidation state of neptunium and the speed of reduction and concurrent oxo group activation was demonstrated. Most notably, reduction kinetics for the NpV O2 +/ /NpIV redox couple upon chelation by the ligands 3,4,3-LI(1,2-HOPO) and 3,4,3-LI(CAM)2 (1,2-HOPO)2 was observed to be faster than ever reported, and in fact quicker than we could measure using either X-ray absorption spectroscopy or electrochemical techniques

    Pathogenicity locus, core genome, and accessory gene contributions to Clostridium difficile virulence

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    Clostridium difficile is a spore-forming anaerobic bacterium that causes colitis in patients with disrupted colonic microbiota. While some individuals are asymptomatic C. difficile carriers, symptomatic disease ranges from mild diarrhea to potentially lethal toxic megacolon. The wide disease spectrum has been attributed to the infected host’s age, underlying diseases, immune status, and microbiome composition. However, strain-specific differences in C. difficile virulence have also been implicated in determining colitis severity. Because patients infected with C. difficile are unique in terms of medical history, microbiome composition, and immune competence, determining the relative contribution of C. difficile virulence to disease severity has been challenging, and conclusions regarding the virulence of specific strains have been inconsistent. To address this, we used a mouse model to test 33 clinical C. difficile strains isolated from patients with disease severities ranging from asymptomatic carriage to severe colitis, and we determined their relative in vivo virulence in genetically identical, antibiotic-pretreated mice. We found that murine infections with C. difficile clade 2 strains (including multilocus sequence type 1/ribotype 027) were associated with higher lethality and that C. difficile strains associated with greater human disease severity caused more severe disease in mice. While toxin production was not strongly correlated with in vivo colonic pathology, the ability of C. difficile strains to grow in the presence of secondary bile acids was associated with greater disease severity. Whole-genome sequencing and identification of core and accessory genes identified a subset of accessory genes that distinguish high-virulence from lower-virulence C. difficile strains

    Brief intervention manual for personality disorders

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    This manual is designed to help services intervene early and better support young people and adults with personality disorders. It is particularly focused on clients in crisis, who have complex needs, by providing practical therapeutic techniques in the prevention and treatment of high-risk challenging behaviours. It describes a four session brief intervention that can act as the first step in a treatment journey for people with this disorder

    Effects of 5-HT2C, 5-HT1A receptor challenges and modafinil on the initiation and persistence of gambling behaviours

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    Rationale Problematic patterns of gambling are characterised by loss of control and persistent gambling often to recover losses. However, little is known about the mechanisms that mediate initial choices to begin gambling and then continue to gamble in the face of losing outcomes. Objectives These experiments first assessed gambling and loss-chasing performance under different win/lose probabilities in C57Bl/6 mice, and then investigated the effects of antagonism of 5-HT2CR with SB242084, 5-HT1AR agonism with 8-OH-DPAT and modafinil, a putative cognitive enhancer. Results As seen in humans and other species, mice demonstrated the expected patterns of behaviour as the odds for winning were altered increasing gambling and loss-chasing when winning was more likely. SB242084 decreased the likelihood to initially gamble, but had no effects on subsequent gambling choices in the face of repeated losses. In contrast, 8-OH-DPAT had no effects on choosing to gamble in the first place, but once started 8-OH-DPAT increased gambling choices in a dose-sensitive manner. Modafinil effects were different to the serotonergic drugs in both decreasing the propensity to initiate gambling and chase losses. Conclusions We present evidence for dissociable effects of systemic drug administration on different aspects of gambling behaviour. These data extend and reinforce the importance of serotonergic mechanisms in mediating discrete components of gambling behaviour. They further demonstrate the ability of modafinil to reduce gambling behaviour. Our work using a novel mouse paradigm may be of utility in modelling the complex psychological and neurobiological underpinnings of gambling problems, including the analysis of genetic and environmental factors

    Tracking Assaultâ injured, Drugâ using Youth in Longitudinal Research: Followâ up Methods

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    ObjectivesViolence is one of the leading causes of death among youth ages 14 to 24. Hospitalâ and emergency department (ED)â based violence prevention programs are increasingly becoming a critical part of public health efforts; however, evaluation of prevention efforts is needed to create evidenceâ based best practices. Retention of study participants is key to evaluations, although little literature exists regarding optimizing followâ up methods for violently injured youth. This study aims to describe the methods for retention in youth violence studies and the characteristics of hardâ toâ reach participants.MethodsThe Flint Youth Injury (FYI) Study is a prospective study following a cohort of assaultâ injured, drugâ using youth recruited in an urban ED, and a comparison population of drugâ using youth seeking medical or nonâ violenceâ related injury care. Validated survey instruments were administered at baseline and four followâ up time points (6, 12, 18, and 24 months). Followâ up contacts used a variety of strategies and all attempts were coded by type and level of success. Regression analysis was used to predict contact difficulty and followâ up interview completion at 24 months.ResultsA total of 599 patients (ages 14â 24) were recruited from the ED (mean ± SD age = 20.1 ± 2.4 years, 41.2% female, 58.2% African American), with followâ up rates at 6, 12, 18, and 24 months of 85.3%, 83.7% 84.2%, and 85.3%, respectively. Participant contact efforts ranged from two to 53 times per followâ up time frame to complete a followâ up appointment, and more than 20% of appointments were completed off site at community locations (e.g., participantsâ homes, jail/prison). Participants who were younger (p < 0.05) and female (p < 0.01) were more likely to complete their 24â month followâ up interview. Participants who sought care in the ED for assault injury (p < 0.05) and had a substance use disorder (p < 0.01) at baseline required fewer contact attempts to complete their 24â month followâ up, while participants reporting a fight within the immediate 3 months before their 24â month followâ up (p < 0.01) required more intensive contact efforts.ConclusionsThe FYI study demonstrated that achieving high followâ up rates for a difficultâ toâ track, violentlyâ injured ED population is feasible through the use of established contact strategies and a variety of interview locations. Results have implications for followâ up strategies planned as part of other violence prevention studies.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146571/1/acem13495_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146571/2/acem13495.pd

    Associations of Skeletal Muscle Mass and Fat Mass With Incident Cardiovascular Disease and All-Cause Mortality: A Prospective Cohort Study of UK Biobank Participants.

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    Background There is debate whether body mass index is a good predictor of health outcomes because different tissues, namely skeletal muscle mass (SMM) and fat mass (FM), may be differentially associated with risk. We investigated the association of appendicular SMM (aSMM) and FM with fatal and nonfatal cardiovascular disease (CVD) and all-cause mortality. We compared their prognostic value to that of body mass index. Methods and Results We studied 356 590 UK Biobank participants aged 40 to 69 years with bioimpedance analysis data for whole-body FM and predicted limb muscle mass (to calculate aSMM). Associations between aSMM and FM with CVD and all-cause mortality were examined using multivariable Cox proportional hazards models. Over 3 749 501 person-years of follow-up, there were 27 784 CVD events and 15 844 all-cause deaths. In men, aSMM was positively associated with CVD incidence (hazard ratio [HR] per 1 SD 1.07; 95% CI, 1.06-1.09) and there was a curvilinear association in women. There were stronger positive associations between FM and CVD with HRs per SD of 1.20 (95% CI, 1.19-1.22) and 1.25 (95% CI, 1.23-1.27) in men and women respectively. Within FM tertiles, the associations between aSMM and CVD risk largely persisted. There were J-shaped associations between aSMM and FM with all-cause mortality in both sexes. Body mass index was modestly better at discriminating CVD risk. Conclusions FM showed a strong positive association with CVD risk. The relationship of aSMM with CVD risk differed between sexes, and potential mechanisms need further investigation. Body fat and SMM bioimpedance measurements were not superior to body mass index in predicting population-level CVD incidence or all-cause mortality

    The Effect of a Food Addiction Explanation Model for Weight Control and Obesity on Weight Stigma

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    There is increasing scientific and public support for the notion that some foods may be addictive, and that poor weight control and obesity may, for some people, stem from having a food addiction. However, it remains unclear how a food addiction model (FAM) explanation for obesity and weight control will affect weight stigma. In two experiments (N = 530 and N = 690), we tested the effect of a food addiction explanation for obesity and weight control on weight stigma. In Experiment 1, participants who received a FAM explanation for weight control and obesity reported lower weight stigma scores (e.g., less dislike of 'fat people', and lower personal willpower blame) than those receiving an explanation emphasizing diet and exercise (F(4,525) = 7.675, p = 0.006; and F(4,525) = 5.393, p = 0.021, respectively). In Experiment 2, there was a significant group difference for the dislike of 'fat people' stigma measure (F(5,684) = 5.157, p = 0.006), but not for personal willpower weight stigma (F(5,684) = 0.217, p = 0.81). Participants receiving the diet and exercise explanation had greater dislike of 'fat people' than those in the FAM explanation and control group (p values 0.05). The FAM explanation for weight control and obesity did not increase weight stigma and resulted in lower stigma than the diet and exercise explanation that attributes obesity to personal control. The results highlight the importance of health messaging about the causes of obesity and the need for communications that do not exacerbate weight stigma

    Global distribution of invasive serotype 35D streptococcus pneumoniae isolates following introduction of 13-valent pneumococcal conjugate vaccine

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    A newly recognized pneumococcal serotype 35D, which differs from the 35B polysaccharide in structure and serology by not binding to factor serum 35a, was recently reported. The genetic basis for this distinctive serology is due to the presence of an inactivating mutation in wciG, which encodes an O-acetyltransferase responsible for O-acetylation of a galactofuranose. Here, we assessed the genomic data of a worldwide pneumococcal collection to identify serotype 35D isolates and understand their geographical distribution, genetic background and invasiveness potential. Of 21,980 pneumococcal isolates, 444 were originally typed as serotype 35B by PneumoCaT. Analysis of wciGrevealed 23 isolates from carriage (n=4) and disease (n=19) with partial or complete loss-of-funtion mutations, including mutations resulting in pre-mature stop codons (n=22) and an in-frame mutation (n=1). These were selected for further analysis. The putative 35D isolates were geographically widespread and 65.2% (15/23) of them was recovered after PCV13 introduction. Compared with serotype 35B, putative serotype 35D isolates have higher invasive disease potentials based on odds ratio (OR) (11.58; 95% CI, 1.42-94.19 vs 0.61; 95% CI, 0.40-0.92) and a higher prevalence of macrolide resistance mediated by mefA (26.1% vs 7.6%, p=0.009). Using Quellung, 50% (10/20) of viable isolates were serotype 35D, 25% (5/20) serotype 35B, and 25% (5/20) a mixture of 35B/35D. The discrepancy between phenotype and genotype requires further investigation. These findings illustrated a global distribution of an invasive serotype 35D among young children post-PCV13 introduction and underlined the invasive potential conferred by the loss of O-acetylation in the pneumococcal capsule

    Associations between types and sources of dietary carbohydrates and liver fat:a UK Biobank study

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    BACKGROUND AND AIMS: Excess energy intake can lead to metabolic dysfunction-associated steatotic liver disease (MASLD), but the relationship between dietary carbohydrate intake and liver fat content remains unclear. This study aimed to examine the associations between types and sources of dietary carbohydrates and liver fat content. METHODS: UK Biobank participants with no pre-existing diabetes, liver disease or cardiovascular disease reported dietary intake of types and sources of carbohydrates (total carbohydrates, free sugars, non-free sugars, starch from whole grains, starch from refined grains, and fibre) on at least two 24-h dietary assessments. In cross-sectional analyses, (n = 22,973), odds ratios (OR) of high liver fat content (defined as a score of ≥ 36 in the hepatic steatosis index) by quintiles of carbohydrate intakes were estimated using multivariable logistic regression models. In prospective analyses, a second sample (n = 9268) had liver proton density fat fraction (PDFF) measured by magnetic resonance imaging (2014-2020). Multivariable linear regression models estimated geometric means of PDFF (%) by quintiles of carbohydrate intakes. Models were adjusted for demographic and lifestyle confounders, including total energy intake. RESULTS: In the cross-sectional analyses, 6894 cases of high liver fat content were identified. Inverse associations between intakes of fibre (OR of highest vs. lowest quintile 0.46 [95% CI: 0.41-0.52]), non-free sugars (0.63 [0.57-0.70]) and starch from whole grains (0.52 [0.47-0.57]) with liver fat were observed. There were positive associations between starch from refined grains and liver fat (1.33 [1.21-1.46]), but no association with free sugars (p=0.61). In prospective analyses, inverse associations with PDFF (%) were observed for intakes of fibre (- 0.48 geometric mean difference between highest and lowest quintile of intake [- 0.60 to - 0.35]), non-free sugars (- 0.37 [- 0.49 to - 0.25]) and starch from whole grains (- 0.31 [- 0.42 to - 0.19]). Free sugars, but not starch from refined grains, were positively associated with PDFF (0.17 [0.05 to 0.28]). CONCLUSION: This study suggests that different carbohydrate types and sources have varying associations with liver fat, which may be important for MASLD prevention. Non-free sugars, fibre, and starch from whole grains could be protective, while associations with free sugars and starch from refined grains are less clear
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