75 research outputs found
Molecular Insights into Appetite Control and Neuroendocrine Disease as Risk Factors for Chronic Diseases in Western Countries
Environmental factors such as stress, anxiety and depression are important to consider with the global increase in chronic diseases such as cardiovascular diseases, cancer, stroke, obesity, diabetes and neurodegenerative diseases. Brain metabolic diseases associated with conditions such as obesity and diabetes require early intervention with diet, lifestyle and drug therapy to prevent diseases to various organs such as the liver with non alcoholic fatty liver disease (NAFLD) and other organs such as the heart, lungs thyroid, pancreas, brain, kidneys and reproductive systems. Behavioural stress and the molecular mechanisms that are involved in neuroendocrine diseases such as insulin resistance in obesity require attention since associated inflammatory processes early in the disease process have been associated with neurodegenerative diseases. Molecular neuroendocrine disturbances that cause appetite dysregulation and hyperphagia are closely linked to hyperinsulinemia, dyslipidaemia and reduced lifespan. The origins of metabolic diseases that afflict various organs possibly arise from hypothalamic disturbances with loss of control of peripheral endocrine hormones and neuropeptides released from the brain. Diet and drug therapies that are directed to the autonomic nervous system, neuroendocrine and limbic systems may help regulate and integrate leptin and insulin signals involving various neuropeptides associated with chronic diseases such as obesity and diabetes. The understanding of brain circuits and stabilization of neuroanatomical structures in the brain is currently under investigation. Research that is involved in the understanding of diet and drugs in the stabilization of brain structures such as frontostriatal limbic circuits, hypothalamus brainstem circuits and parasympathetic nervous system is required. Information related to neuropeptides and neurotransmitters that are released from the brain and their regulation by therapeutic drugs requires further assessment. The promise of appropriate diets, lifestyle and drugs that target the CNS and peripheral tissues such as the adipose tissue, liver and pancreas may improve the prognosis of chronic diseases such as obesity and diabetes that are also closely associated with neurodegeneration
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Dynamic MAIT cell response with progressively enhanced innateness during acute HIV-1 infection.
Mucosa-associated invariant T (MAIT) cell loss in chronic HIV-1 infection is a significant insult to antimicrobial immune defenses. Here we investigate the response of MAIT cells during acute HIV-1 infection utilizing the RV217 cohort with paired longitudinal pre- and post-infection samples. MAIT cells are activated and expand in blood and mucosa coincident with peak HIV-1 viremia, in a manner associated with emerging microbial translocation. This is followed by a phase with elevated function as viral replication is controlled to a set-point level, and later by their functional decline at the onset of chronic infection. Interestingly, enhanced innate-like pathways and characteristics develop progressively in MAIT cells during infection, in parallel with TCR repertoire alterations. These findings delineate the dynamic MAIT cell response to acute HIV-1 infection, and show how the MAIT compartment initially responds and expands with enhanced function, followed by progressive reprogramming away from TCR-dependent antibacterial responses towards innate-like functionality
Optical absorption spectra in fullerenes C60 and C70: Effects of Coulomb interactions, lattice fluctuations, and anisotropy
Effects of Coulomb interactions and lattice fluctuations in the optical
absorption spectra of C60 and C70 are theoretically investigated by using a
tight binding model with long-range Coulomb interaction and bond disorder.
Anisotropy effects in C70 are also considered. Optical spectra are calculated
by using the Hartree-Fock approximation followed by the configuration
interaction method. The main conclusions are as follows: (1) The broad peaks at
excitation energies, 3.7eV, 4.7eV, and 5.7eV, observed in experiments of C60
molecules in a solution are reasonably described by the present theory. Peak
positions and relative oscillator strengths are in overall agreement with the
experiments. The broadening of peaks by lattice fluctuations is well simulated
by the bond disorder model. (2) The optical gap of C70 is larger when the
electric field of light is parallel to the long axis of the molecule. The shape
of the frequency dispersion also depends on the orientation of the molecule.
These properties are common in the free electron model and the model with
Coulomb interactions. (3) The spectrum of C70 averaged over bond disorder and
random orientations is compared with experiments in a solution. There is an
overall agreement about the spectral shape. Differences in the spectra of C60
and C70 are discussed in connection with the symmetry reduction from a
soccerball to a rugbyball.Comment: PACS numbers: 78.66.Qn, 78.20.Dj, 71.35.+z, 31.20.Tz; LaTeX, 15
pages, 5 figures (Physical Review B); Note: Please request figures to
Authors. They will be sent via snail mai
Observation and Assignment of Silent and Higher Order Vibrations in the Infrared Transmission of C60 Crystals
We report the measurement of infrared transmission of large C60 single
crystals. The spectra exhibit a very rich structure with over 180 vibrational
absorptions visible in the 100 - 4000 cm-1 range. Many silent modes are
observed to have become weakly IR-active. We also observe a large number of
higher order combination modes. The temperature (77K - 300K) and pressure (0 -
25KBar) dependencies of these modes were measured and are presented. Careful
analysis of the IR spectra in conjunction with Raman scattering data showing
second order modes and neutron scattering data, allow the selection of the 46
vibrational modes C60. We are able to fit *all* of the first and second order
data seen in the present IR spectra and the previously published Raman data
(~300 lines total), using these 46 modes and their group theory allowed second
order combinations.Comment: REVTEX v3.0 in LaTeX. 12 pages. 8 Figures by request. c60lon
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The heterogeneity of wooded-agricultural landscape mosaics influences woodland bird community assemblages
Context
Landscape heterogeneity (the composition and configuration of different landcover types) plays a key role in shaping woodland bird assemblages in wooded-agricultural mosaics. Understanding how species respond to landscape factors could contribute to preventing further decline of woodland bird populations.
Objective
To investigate how woodland birds with different species traits respond to landscape heterogeneity, and to identify whether specific landcover types are important for maintaining diverse populations in wooded-agricultural environments.
Methods
Birds were sampled from woodlands in 58 2 x 2 km tetrads across southern Britain. Landscape heterogeneity was quantified for each tetrad. Bird assemblage response was determined using redundancy analysis combined with variation partitioning and response trait analyses.
Results
For woodland bird assemblages, the independent explanatory importance of landscape composition and landscape configuration variables were closely interrelated. When considered simultaneously during variation partitioning, the community response was better represented by compositional variables. Different species responded to different landscape features and this could be explained by traits relating to woodland association, foraging strata and nest location. Ubiquitous, generalist species, many of which were hole-nesters or ground foragers, correlated positively with urban landcover while specialists of broadleaved woodland avoided landscapes containing urban areas. Species typical of coniferous woodland correlated with large conifer plantations.
Conclusions
At the 2 x 2 km scale, there was evidence that the availability of resources provided by proximate landcover types was highly important for shaping woodland bird assemblages. Further research to disentangle the effects of composition and configuration at different spatial scales is advocated
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THE MATERHORN: Unraveling the Intricacies of Mountain Weather
Emerging application areas such as air pollution in megacities, wind energy, urban security, and operation of unmanned aerial vehicles have intensified scientific and societal interest in mountain meteorology. To address scientific needs and help improve the prediction of mountain weather, the U.S. Department of Defense has funded a research effort—the Mountain Terrain Atmospheric Modeling and Observations (MATERHORN) Program—that draws the expertise of a multidisciplinary, multi-institutional, and multinational group of researchers. The program has four principal thrusts, encompassing modeling, experimental, technology, and parameterization components, directed at diagnosing model deficiencies and critical knowledge gaps, conducting experimental studies, and developing tools for model improvements. The access to the Granite Mountain Atmospheric Sciences Testbed of the U.S. Army Dugway Proving Ground, as well as to a suite of conventional and novel high-end airborne and surface measurement platforms, has provided an unprecedented opportunity to investigate phenomena of time scales from a few seconds to a few days, covering spatial extents of tens of kilometers down to millimeters. This article provides an overview of the MATERHORN and a glimpse at its initial findings. Orographic forcing creates a multitude of time-dependent submesoscale phenomena that contribute to the variability of mountain weather at mesoscale. The nexus of predictions by mesoscale model ensembles and observations are described, identifying opportunities for further improvements in mountain weather forecasting
Transcriptomic signatures of NK cells suggest impaired responsiveness in HIV-1 infection and increased activity post-vaccination
Natural killer (NK) cells limit viral replication by direct recognition of infected cells, antibody-dependent cellular cytotoxicity (ADCC), and releasing cytokines. Although growing evidence supports NK cell antiviral immunity in HIV-1 infection, further knowledge of their response is necessary. Here we show that NK cells responding to models of direct cell recognition, ADCC, and cytokine activation have unique transcriptional fingerprints. Compared with healthy volunteers, individuals with chronic HIV-1 infection have higher expression of genes commonly associated with activation, and lower expression of genes associated with direct cell recognition and cytokine stimulation in their NK cells. By contrast, NK cell transcriptional profiles of individuals receiving a modified vaccinia Ankara (MVA) vectored HIV-1 vaccine show upregulation of genes associated with direct cell recognition. These findings demonstrate that targeted transcriptional profiling provides a sensitive assessment of NK cell activity, which helps understand how NK cells respond to viral infections and vaccination
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