291 research outputs found
Reconsideration of Second Harmonic Generation from neat Air/Water Interface: Broken of Kleinman Symmetry from Dipolar Contribution
It has been generally accepted that there are significant quadrupolar and
bulk contributions to the second harmonic generation (SHG) reflected from the
neat air/water interface, as well as common liquid interfaces. Because there
has been no general methodology to determine the quadrupolar and bulk
contributions to the SHG signal from a liquid interface, this conclusion was
reached based on the following two experimental phenomena. Namely, the broken
of the macroscopic Kleinman symmetry, and the significant temperature
dependence of the SHG signal from the neat air/water interface. However,
because sum frequency generation vibrational spectroscopy (SFG-VS) measurement
of the neat air/water interface observed no apparent temperature dependence,
the temperature dependence in the SHG measurement has been reexamined and
proven to be an experimental artifact. Here we present a complete microscopic
analysis of the susceptibility tensors of the air/water interface, and show
that dipolar contribution alone can be used to address the issue of broken of
the macroscopic Kleinman symmetry at the neat air/water interface. Using this
analysis, the orientation of the water molecules at the interface can be
obtained, and it is consistent with the measurement from SFG-VS. Therefore, the
key rationales to conclude significantly quadrupolar and bulk contributions to
the SHG signal of the neat air/water interface can no longer be considered as
valid as before. This new understanding of the air/water interface can shed
light on our understanding of the nonlinear optical responses from other
molecular interfaces as well
Molecular dynamics of ionic liquids confined in solid silica matrix for lithium batteries
We present the first results of the magnetic field dependence of the longitudinal nuclear magnetic relaxation of anion-cation
pair of ionic liquids (Li+-ionogels) confined within a silica-like mesoporous matrices designed for lithium batteries. These results are in favour of a very-correlated dynamical motion of the anion-cation pair within the solid and disordered silica matrix
Second harmonic generation response by gold nanoparticles at the polarized water/2-octanone interface: from dispersed to aggregated particles
Substrate recognition by class I lysyl-tRNA synthetases: A molecular basis for gene displacement
Measurement of the d36 coefficient of mercury cadmium telluride by reflection second harmonic generation
16p11.2 locus modulates response to satiety before the onset of obesity
Background: The 600 kb BP4-BP5 copy number variants (CNVs) at the 16p11.2 locus have been associated with a range of neurodevelopmental conditions including autism spectrum disorders and schizophrenia. The number of genomic copies in this region is inversely correlated with body mass index (BMI): the deletion is associated with a highly penetrant form of obesity (present in 50% of carriers by the age of 7 years and in 70% of adults), and the duplication with being underweight. Mechanisms underlying this energy imbalance remain unknown. Objective: This study aims to investigate eating behavior, cognitive traits and their relationships with BMI in carriers of 16p11.2 CNVs. Methods: We assessed individuals carrying a 16p11.2 deletion or duplication and their intrafamilial controls using food-related behavior questionnaires and cognitive measures. We also compared these carriers with cohorts of individuals presenting with obesity, binge eating disorder or bulimia. Results: Response to satiety is gene dosage-dependent in pediatric CNV carriers. Altered satiety response is present in young deletion carriers before the onset of obesity. It remains altered in adolescent carriers and correlates with obesity. Adult deletion carriers exhibit eating behavior similar to that seen in a cohort of obesity without eating disorders such as bulimia or binge eating. None of the cognitive measures are associated with eating behavior or BMI. Conclusions: These findings suggest that abnormal satiety response is a strong contributor to the energy imbalance in 16p11.2 CNV carriers, and, akin to other genetic forms of obesity, altered satiety responsiveness in children precedes the increase in BMI observed later in adolescence
16p11.2 Locus modulates response to satiety before the onset of obesity
Background:
The 600 kb BP4-BP5 copy number variants (CNVs) at the 16p11.2 locus have been associated with a range of neurodevelopmental conditions including autism spectrum disorders and schizophrenia. The number of genomic copies in this region is inversely correlated with body mass index (BMI): the deletion is associated with a highly penetrant form of obesity (present in 50% of carriers by the age of 7 years and in 70% of adults), and the duplication with being underweight. Mechanisms underlying this energy imbalance remain unknown.
Objective:
This study aims to investigate eating behavior, cognitive traits and their relationships with BMI in carriers of 16p11.2 CNVs.
Methods:
We assessed individuals carrying a 16p11.2 deletion or duplication and their intrafamilial controls using food-related behavior questionnaires and cognitive measures. We also compared these carriers with cohorts of individuals presenting with obesity, binge eating disorder or bulimia.
Results:
Response to satiety is gene dosage-dependent in pediatric CNV carriers. Altered satiety response is present in young deletion carriers before the onset of obesity. It remains altered in adolescent carriers and correlates with obesity. Adult deletion carriers exhibit eating behavior similar to that seen in a cohort of obesity without eating disorders such as bulimia or binge eating. None of the cognitive measures are associated with eating behavior or BMI.
Conclusions:
These findings suggest that abnormal satiety response is a strong contributor to the energy imbalance in 16p11.2 CNV carriers, and, akin to other genetic forms of obesity, altered satiety responsiveness in children precedes the increase in BMI observed later in adolescence
Side Chain Independent Recognition of Aminoacyl Adenylates by the Hint1 Transcription Suppressor
Multi-level analysis of the gut-brain axis shows autism spectrum disorder-associated molecular and microbial profiles
Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by heterogeneous cognitive, behavioral and communication impairments. Disruption of the gut-brain axis (GBA) has been implicated in ASD although with limited reproducibility across studies. In this study, we developed a Bayesian differential ranking algorithm to identify ASD-associated molecular and taxa profiles across 10 cross-sectional microbiome datasets and 15 other datasets, including dietary patterns, metabolomics, cytokine profiles and human brain gene expression profiles. We found a functional architecture along the GBA that correlates with heterogeneity of ASD phenotypes, and it is characterized by ASD-associated amino acid, carbohydrate and lipid profiles predominantly encoded by microbial species in the genera Prevotella, Bifidobacterium, Desulfovibrio and Bacteroides and correlates with brain gene expression changes, restrictive dietary patterns and pro-inflammatory cytokine profiles. The functional architecture revealed in age-matched and sex-matched cohorts is not present in sibling-matched cohorts. We also show a strong association between temporal changes in microbiome composition and ASD phenotypes. In summary, we propose a framework to leverage multi-omic datasets from well-defined cohorts and investigate how the GBA influences ASD
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