2,044 research outputs found
A brief mindfulness-based intervention reduces eating disorder symptoms and improves eating self-efficacy and emotion regulation among adults seeking bariatric surgery
Background Up to 64% of bariatric (weight-loss) surgery-seeking adults report eating disorder (ED) symptoms (i.e., binge eating, emotional eating, addictive-like eating, and grazing) that can interfere with surgery outcomes. Well-designed pre-surgical interventions targeting eating behaviours may reduce ED symptoms and protect against suboptimal surgery outcomes.
Objectives Provide proof-of-concept data to inform the design and optimization of a pre-surgical mindfulness-based intervention (MBI) for ED symptoms. Evaluate whether the MBI produces meaningful improvements in ED symptoms and clarify the mechanisms-of-action by which the MBI impacts ED symptoms.
Methods Twenty-one pre-surgical patients with obesity and ED symptoms referred to a MBI completed self-report measures of addictive-like eating, binge eating, emotional eating, grazing, mindful eating, eating self-efficacy, and emotion regulation pre-(T1) and post-(T2) MBI.
Results Repeated-measures ANOVAs revealed improvements in binge eating symptoms (F (1,20) = 30.38, ηp2 = .60, p < .001) and grazing (F (1,20) = 7.57, ηp2 = .28, p = .012), pre- to post-MBI. Adjusting for multiple comparisons, no significant improvements were found for addictive-like eating or emotional eating. Eating self-efficacy (F (1,20) = 29.70, ηp2 = .60, p < .001) and emotion regulation (F (1,20) = 7.18, ηp2 = .26, p = .014) improved, while mindful eating decreased (F (1,20) = 16.25, ηp2 = .45, p = .001), following the MBI. Bivariate correlations found associations between improvements in the mechanism of eating self-efficacy and improvements in the ED symptom of grazing pre- to post-MBI (r = 0.46, p < .05). As well, improvements in emotion regulation were associated with positive changes in binge and emotional eating and grazing (r = 0.55, p < .001, r = 0.66, p < .001, r = 0.61, p < .05, respectively).
Conclusions After participating in the MBI binge eating, grazing, eating self-efficacy, and emotion regulation abilities improved. Further work is needed to understand and mitigate deterioration in mindful eating. Moreover, acceptability and feasibility of the MBI should be assessed prior to testing the MBI in a large-scale efficacy trial. Future research should assess the the impact of this intervention on post-surgery weight-loss, weight-loss maintenance, and maintenance of improvements in ED symptoms
An Exploratory Analysis of Personality, Attitudes, and Study Skills on the Learning Curve within a Team-based Learning Environment
Objective. To examine factors that determine the interindividual variability of learning within a team-based learning environment
Space-time evolution of electron cascades in diamond
Here we describe model calculations to follow the spatio-temporal evolution
of secondary electron cascades in diamond. The band structure of the insulator
has been explicitly incorporated into the calculations as it affects
ionizations from the valence band. A Monte-Carlo model was constructed to
describe the path of electrons following the impact of a single electron of
energy E 250 eV. The results show the evolution of the secondary electron
cascades in terms of the number of electrons liberated, the spatial
distribution of these electrons, and the energy distribution among the
electrons as a function of time. The predicted ionization rates (5-13 electrons
in 100 fs) lie within the limits given by experiments and phenomenological
models. Calculation of the local electron density and the corresponding Debye
length shows that the latter is systematically larger than the radius of the
electron cloud. This means that the electron gas generated does not represent a
plasma in a single impact cascade triggered by an electron of E 250 eV energy.
This is important as it justifies the independent-electron approximation used
in the model. At 1 fs, the (average) spatial distribution of secondary
electrons is anisotropic with the electron cloud elongated in the direction of
the primary impact. The maximal radius of the cascade is about 50 A at this
time. As the system cools, energy is distributed more equally, and the spatial
distribution of the electron cloud becomes isotropic. At 90 fs maximal radius
is about 150 A. The Monte-Carlo model described here could be adopted for the
investigation of radiation damage in other insulators and has implications for
planned experiments with intense femtosecond X-ray sources.Comment: 26 pages, latex, 13 figure
Alcohol Consumption is associated with Increased CEA Levels in Male Patients with Stage IV Colorectal Cancer- A Single-Institution Retrospective Analysis
Introduction: Alcohol use is an independent risk factor for liver metastasis, a major cause of morbidity and mortality in colorectal cancer (CRC) patients. Serum CEA level is an established prognostic indicator in CRC, yet the correlation with behavioral factors such as alcohol use remains to be defined. In a single-center review, we evaluated alcohol use, gender, and CEA levels in predicting advanced disease in CRC patients.
Methods: Retrospective analysis of UNMC patients diagnosed with CRC as the primary cancer between 2012-2019, stages I-IV, and age \u3e19 with documentation of alcohol use. Univariable statistics were performed using Chi-Square and non-parametric tests. Associations between stage, gender, and alcohol use (some vs. none) and the log-transformed CEA outcome (either initial or rate of change) were assessed using linear regressions.
Results: Alcohol use was found to be reported in 333 of 1243 CRC patients. The cohort was comprised of 192 male and 141 female subjects. Elevated CEA levels at CRC diagnosis were associated with increased all-cause mortality (33.0% for CEA \u3e 3.4ng/ml vs 10.4% for CEA \u3c 3.4ng/ml). Model analysis found that stage IV male alcohol users showed an increase in serial CEA levels compared to males who did not use alcohol, but this pattern was not observed among stage IV females.
Conclusions: Males with a history of alcohol use may be at risk for advanced CRC disease suggesting the utility of serial serum CEA monitoring in these patients. A detailed alcohol use history should be obtained in all patients with CRC as it has prognostic value and may allow for early intervention. This analysis was limited by missing alcohol use data for the majority (73.2%) of CRC patients evaluated. A prospective study is warranted to define the implications of alcohol use and risk of CRC liver metastasis
Resolving the cofactor-binding site in the proline biosynthetic enzyme human pyrroline-5-carboxylate reductase 1
Pyrroline-5-carboxylate reductase (PYCR) is the final enzyme in proline biosynthesis, catalyzing the NAD(P)H-dependent reduction of [?]1-pyrroline-5-carboxylate (P5C) to proline. Mutations in the PYCR1 gene alter mitochondrial function and cause the connective tissue disorder cutis laxa. Furthermore, PYCR1 is overexpressed in multiple cancers, and the PYCR1 knock-out suppresses tumorigenic growth, suggesting that PYCR1 is a potential cancer target. However, inhibitor development has been stymied by limited mechanistic details for the enzyme, particularly in light of a previous crystallographic study that placed the cofactor-binding site in the C-terminal domain rather than the anticipated Rossmann fold of the N-terminal domain. To fill this gap, we report crystallographic, sedimentation- velocity, and kinetics data for human PYCR1. Structures of binary complexes of PYCR1 with NADPH or proline determined at 1.9 Å resolution provide insight into cofactor and substrate recognition.WeseeNADPHbound to the Rossmann fold, over 25 Å from the previously proposed site. The 1.85 Å resolution structure of a ternary complex containing NADPH and a P5C/proline analog provides a model of the Michaelis complex formed during hydride transfer. Sedimentation velocity shows that PYCR1 forms a concentration-dependent decamer in solution, consistent with the pentamer-of-dimers assembly seen crystallographically. Kinetic and mutational analysis confirmed several features seen in the crystal structure, including the importance of a hydrogen bond between Thr-238 and the substrate as well as limited cofactor discrimination
Oral cavity squamous cell carcinoma xenografts retain complex genotypes and intertumor molecular heterogeneity
Effects of increasing the affinity of CarD for RNA polymerase on Mycobacterium tuberculosis growth, rRNA transcription, and virulence
CarD is an essential RNA polymerase (RNAP) interacting protein in Mycobacterium tuberculosis that stimulates formation of RNAP-promoter open complexes. CarD plays a complex role in M. tuberculosis growth and virulence that is not fully understood. Therefore, to gain further insight into the role of CarD in M. tuberculosis growth and virulence, we determined the effect of increasing the affinity of CarD for RNAP. Using site-directed mutagenesis guided by crystal structures of CarD bound to RNAP, we identified amino acid substitutions that increase the affinity of CarD for RNAP. Using these substitutions, we show that increasing the affinity of CarD for RNAP increases the stability of the CarD protein in M. tuberculosis. In addition, we show that increasing the affinity of CarD for RNAP increases the growth rate in M. tuberculosis without affecting 16S rRNA levels. We further show that increasing the affinity of CarD for RNAP reduces M. tuberculosis virulence in a mouse model of infection despite the improved growth rate in vitro. Our findings suggest that the CarD-RNAP interaction protects CarD from proteolytic degradation in M. tuberculosis, establish that growth rate and rRNA levels can be uncoupled in M. tuberculosis and demonstrate that the strength of the CarD-RNAP interaction has been finely tuned to optimize virulence. IMPORTANCE Mycobacterium tuberculosis, the causative agent of tuberculosis, remains a major global health problem. In order to develop new strategies to battle this pathogen, we must gain a better understanding of the molecular processes involved in its survival and pathogenesis. We have previously identified CarD as an essential transcriptional regulator in mycobacteria. In this study, we detail the effects of increasing the affinity of CarD for RNAP on transcriptional regulation, CarD protein stability, and virulence. These studies expand our understanding of the global transcription regulator CarD, provide insight into how CarD activity is regulated, and broaden our understanding of prokaryotic transcription
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Redox Fluctuations Control the Coupled Cycling of Iron and Carbon in Tropical Forest Soils.
Oscillating redox conditions are a common feature of humid tropical forest soils, driven by an ample supply and dynamics of reductants, high moisture, microbial oxygen consumption, and finely textured clays that limit diffusion. However, the net result of variable soil redox regimes on iron (Fe) mineral dynamics and associated carbon (C) forms and fluxes is poorly understood in tropical soils. Using a 44-day redox incubation experiment with humid tropical forest soils from Puerto Rico, we examined patterns in Fe and C transformations under four redox regimes: static anoxic, "flux 4-day" (4d oxic, 4d anoxic), "flux 8-day" (8d oxic, 4d anoxic) and static oxic. Prolonged anoxia promoted reductive dissolution of Fe-oxides, and led to an increase in soluble Fe(II) and amorphous Fe oxide pools. Preferential dissolution of the less-crystalline Fe pool was evident immediately following a shift in bulk redox status (oxic to anoxic), and coincided with increased dissolved organic C, presumably due to acidification or direct release of organic matter (OM) from dissolving Fe(III) mineral phases. The average nominal oxidation state of water-soluble C was lowest under persistent anoxic conditions, suggesting that more reduced organic compounds were metabolically unavailable for microbial consumption under reducing conditions. Anoxic soil compounds had high H/C values (and were similar to lignin-like compounds) whereas oxic soil compounds had higher O/C values, akin to tannin- and cellulose-like components. Cumulative respiration derived from native soil organic C was highest in static oxic soils. These results show how Fe minerals and Fe-OM interactions in tropical soils are highly sensitive to variable redox effects. Shifting soil oxygen availability rapidly impacted exchanges between mineral-sorbed and aqueous C pools, increased the dissolved organic C pool under anoxic conditions implying that the periodicity of low-redox events may control the fate of C in wet tropical soils
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