38 research outputs found
Quantum dynamical phenomena of independent electrons in semiconductor superlattices subject to a uniform electric field
We solve the time-dependent Schrodinger equation for independent electrons in both periodic and aperiodic semiconductor superlattices with a superimposed static uniform electric field, F, using both analytical and numerical methods. In the case of periodic superlattices, in suitable circumstances the electron exhibits Bloch oscillations in the form of long-lived and virtually time-periodic sinusoidal center-of-mass oscillations. Depending on the miniband structure of the superlattice, the value of F, and the detailed form of the initial wave function, other dynamical phenomena can occur which can coexist with or even totally mask the Bloch oscillations. These include a nearly time-periodic coherent breathing mode, an unbounded acceleration of a portion of the electron wave packet antiparallel to the electric field, and high-frequency intra-well oscillations;With the introduction of an aperiodic potential term into the independent electron Hamiltonian, we find that the electron of course no longer exhibits time-periodic Bloch oscillations. Depending on the strength of the impurity potential, the miniband structure of the impurity-free superlattice, the value of F, and the initial wave function, the electron can exhibit almost-periodic oscillations, acceleration effects, intra-well oscillations, and Bloch-like oscillations of moderate lifetime which then give way to almost-periodic oscillations. We speculate that almost-periodic oscillations due to scattering from impurities could give rise to the rapid signal decay observed in recent experiments to detect Bloch oscillations in narrow-miniband superlattices. We propose that experiments based on wide-miniband superlattices may provide an opportunity to observe more Bloch-like oscillations than have ever been observed before
Associations between dietary patterns and gene expression profiles of healthy men and women: a cross-sectional study
Background: Diet regulates gene expression profiles by several mechanisms. The objective of this study was to
examine gene expression in relation with dietary patterns.
Methods: Two hundred and fifty four participants from the greater Quebec City metropolitan area were recruited.
Two hundred and ten participants completed the study protocol. Dietary patterns were derived from a food
frequency questionnaire (FFQ) by factor analysis. For 30 participants (in fasting state), RNA was extracted from
peripheral blood mononuclear cells (PBMCs) and expression levels of 47,231 mRNA transcripts were assessed using
the Illumina Human-6 v3 Expression BeadChipsW. Microarray data was pre-processed with Flexarray software and
analysed with Ingenuity Pathway Analysis (IPA).
Results: Two dietary patterns were identified. The Prudent dietary pattern was characterised by high intakes of
vegetables, fruits, whole grain products and low intakes of refined grain products and the Western dietary pattern,
by high intakes of refined grain products, desserts, sweets and processed meats. When individuals with high scores
for the Prudent dietary pattern where compared to individuals with low scores, 2,083 transcripts were differentially
expressed in men, 1,136 transcripts in women and 59 transcripts were overlapping in men and women. For the
Western dietary pattern, 1,021 transcripts were differentially expressed in men with high versus low scores, 1,163
transcripts in women and 23 transcripts were overlapping in men and women. IPA reveals that genes differentially
expressed for both patterns were present in networks related to the immune and/or inflammatory response, cancer
and cardiovascular diseases.
Conclusion: Gene expression profiles were different according to dietary patterns, which probably modulate the
risk of chronic diseases
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Mediation Analysis Supports a Causal Relationship between Maternal Hyperglycemia and Placental DNA Methylation Variations at the Leptin Gene Locus and Cord Blood Leptin Levels.
Changes in fetal DNA methylation (DNAm) of the leptin (LEP) gene have been associated with exposure to maternal hyperglycemia, but their links with childhood obesity risk are still unclear. We investigated the association between maternal hyperglycemia, placental LEP DNAm (25 5-C-phosphate-G-3 (CpG) sites), neonatal leptinemia, and adiposity (i.e., BMI and skinfold thickness (ST) (subscapular (SS) + triceps (TR) skinfold measures, and the ratio of SS:TR) at 3-years-old, in 259 mother-child dyads, from Gen3G birth cohort. We conducted multivariate linear analyses adjusted for gestational age at birth, sex of the child, age at follow-up, and cellular heterogeneity. We assessed the causal role of DNAm in the association between maternal glycemia and childhood outcomes, using mediation analysis. We found three CpGs associated with neonatal leptinemia (p ≤ 0.002). Of these, cg05136031 and cg15758240 were also associated with BMI (β = -2.69, p = 0.05) and fat distribution (β = -0.581, p = 0.05) at 3-years-old, respectively. Maternal glycemia was associated with DNAm at cg15758240 (β = -0.01, p = 0.04) and neonatal leptinemia (β = 0.19, p = 0.004). DNAm levels at cg15758240 mediates 0.8% of the association between maternal glycemia and neonatal leptinemia (p < 0.001). Our results support that DNAm regulation of the leptin pathway in response to maternal glycemia might be involved in programming adiposity in childhood
Sensory-based nutrition pilot intervention for women
Negative effects of restrained eating (ie, concerns about dieting and weight control) have been observed in eating behaviors. Such findings underscore the need to develop more positive approaches to promote healthy eating behaviors. The objectives of this pilot randomized controlled trial were to investigate and determine whether sensory-based intervention influenced eating-related attitudes and behaviors among restrained women, as well as reliance on physical signals for hunger and satiety. Between January and September 2011, data were collected using validated questionnaires (Restraint Scale, Three-Factor Eating Questionnaire, Mindful Eating Questionnaire, and Intuitive Eating Scale) at baseline (T=1), the end of the intervention period (T=2), and 12 weeks post intervention (T=3). At T=1, women (n=50) from Quebec City, Canada, were randomly assigned to an intervention group (sensory-based intervention) or a waiting list control group. Statistical analyses were conducted using mixed models, including the group, time, and group-by-time interaction. Women from the intervention group showed a significant decrease in Three-Factor Eating Questionnaire-Disinhibition and a significant increase in Mindful Eating Questionnaire-Disinhibition at T=2 vs T=3 (P=0.02 and P=0.02, respectively) and at T=3 vs T=1 (P=0.003 and P=0.002, respectively). Women from the intervention group also showed a significant increase in Intuitive Eating Scale-Unconditional Permission to Eat at T=2 vs T=1 (P<0.0001) and at T=3 vs T=1 (P<0.0001). These preliminary data suggest that sensory-based intervention can be a promising approach to improve eating-related attitudes and behaviors among restrained women, without exacerbating other behaviors such as restrained eating
Effects of age, sex, body mass index and APOE genotype on cardiovascular biomarker response to an n-3 polyunsaturated fatty acid supplementation
Objectives: To test whether age, sex, body mass index (BMI), and the apolipoprotein E (APOE)
genotype are associated with the metabolic response to an n-3 polyunsaturated fatty acid
(PUFA) supplementation. Methods: 210 subjects followed a 2-week run-in period based on
Canada’s Food Guide and underwent a 6-week 5 g/day fish oil supplementation (1.9 g of
eicosapentaenoic acid and 1.1 g of docosahexaenoic acid). Cardiovascular disease risk factors
were measured. Results: n-3 PUFA supplementation was associated with a decrease of plasma
triglyceride levels (p = 0.0002) as well as with an increase of fasting glucose (FG) levels (p =
0.02). Age was associated with post-intervention plasma total cholesterol (p = 0.01), low-density lipoprotein cholesterol (p = 0.007), apolipoprotein B (p = 0.04), and insulin (p = 0.002)
levels. Sex was associated with post-intervention plasma high-density lipoprotein cholesterol
levels (p = 0.02). BMI was associated with plasma FG (p = 0.02) and insulin levels (p < 0.0001)
after the supplementation. APOE genotype was associated with FG (p = 0.001) and C-reactive
protein levels (p = 0.03) after the supplementation. Conclusion: Results suggest that age, sex,
BMI, and the APOE genotype contribute to the inter-individual variability observed in the
metabolic response to an n-3 PUFA supplementation
Effect of sensory-based intervention on the increased use of food-related descriptive terms among restrained eaters
The goals of this pilot randomized controlled trial were to investigate and determine whether sensorybased
intervention influenced the number and type of terms (descriptive and hedonic) used by restrained
women to describe a certain food, and whether changes in the number of descriptive terms were associated
with changes in intuitive eating. We collected data at baseline (T = 1), at the end of the intervention
period (T = 2), and at 12 weeks post-intervention (T = 3) using the descriptive form and Intuitive Eating
Scale (IES). At T = 1, 50 women were randomly assigned to an intervention group (sensory-based intervention)
or a control group (waiting list). To determine the effect of intervention over time on the number
of descriptive and hedonic terms, we conducted statistical analyses using mixed models. To determine
associations between Intuitive Eating Scale subscales and the number of descriptive terms, we also calculated
Spearman correlation coefficients. We noted a significant group-by-time interaction for descriptive
terms associated with all senses (p < 0.04), except for a sight-related trend (p = 0.06). In comparison
with T = 1, intervention group women at T = 2 and T = 3 showed a significant increase in descriptive terms
associated with smell (p = 0.0002 and p = 0.03, respectively), taste (p = 0.001 and p = 0.01, respectively)
and hearing (p = 0.04 and p = 0.0003, respectively). Among intervention group women, we noted a positive
correlation between changes (T = 3 vs. T = 2) in the number of descriptive terms used and changes in
reliance on internal hunger and satiety cues (r = 0.48; p = 0.04), as well as between changes (T = 3 vs.
T = 1) in the number of descriptive terms used and changes in unconditional permission to eat
(r = 0.45; p = 0.05). Overall, these data show that sensory-based intervention may help restrained women
become more objective and enjoyably connected to food and their own bodies, which may promote a
more intuitive approach to eating
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Novel collaboration and situational awareness environment for leaders and their support staff via self assembling software.
This is the final report on the Sandia Fellow LDRD, project 117865, 08-0281. This presents an investigation of self-assembling software intended to create shared workspace environment to allow online collaboration and situational awareness for use by high level managers and their teams
Risk of newly detected infections and cervical abnormalities in adult women seropositive or seronegative for naturally acquired HPV-16/18 antibodies
Funder: GlaxoSmithKline Biologicals SAPeer reviewedPublisher PD
New genetic loci link adipose and insulin biology to body fat distribution.
Body fat distribution is a heritable trait and a well-established predictor of adverse metabolic outcomes, independent of overall adiposity. To increase our understanding of the genetic basis of body fat distribution and its molecular links to cardiometabolic traits, here we conduct genome-wide association meta-analyses of traits related to waist and hip circumferences in up to 224,459 individuals. We identify 49 loci (33 new) associated with waist-to-hip ratio adjusted for body mass index (BMI), and an additional 19 loci newly associated with related waist and hip circumference measures (P < 5 × 10(-8)). In total, 20 of the 49 waist-to-hip ratio adjusted for BMI loci show significant sexual dimorphism, 19 of which display a stronger effect in women. The identified loci were enriched for genes expressed in adipose tissue and for putative regulatory elements in adipocytes. Pathway analyses implicated adipogenesis, angiogenesis, transcriptional regulation and insulin resistance as processes affecting fat distribution, providing insight into potential pathophysiological mechanisms