Local fluctuations in solution mixtures.
Ontology highlight
ABSTRACT:
SUBMITTER: Ploetz EA
PROVIDER: S-EPMC3160452 | biostudies-other | 2011 Jul
REPOSITORIES: biostudies-other
Similar Datasets
Project description:The method developed in a previous paper [R. Mazo, J. Chem. Phys. 129, 154101 (2008)] for extracting information on the size of relative fluctuations in multicomponent systems is tested on ten binary systems and one ternary system. For the binary systems, it is found that the approximation works well for mole fractions in the range of 0.15-0.85 in most cases. For the ternary case, the method inherently yields less information and is valid only over a more restricted range for the case studied (chloroform-methanol-acetone). It is found that the predicted ratio of number fluctuations is approximately equal to the ratio of molar volumes of the components.
| S-EPMC2719477 | biostudies-other
Project description:Critical fluctuations are investigated in lipid membranes near miscibility critical points in bilayers composed of dioleoylphosphatidylcholine, chain perdeuterated dipalmitoylphosphatidylcholine, and cholesterol. Phase boundaries are mapped over the temperature range from 10 degrees C to 60 degrees C by deuterium NMR. Tie-lines and three-phase triangles are evaluated across two-phase and three-phase regions, respectively. In addition, a line of miscibility critical points is identified. NMR resonances are broadened in the vicinity of critical points, and broadening is attributed to increased transverse relaxation rates arising from modulation of chain order with correlation times on a microsecond time scale. We conclude that spectral broadening arises from composition fluctuations in the membrane plane with dimensions of <50 nm and speculate that similar fluctuations are commonly found in cholesterol-containing membranes.
| S-EPMC2077022 | biostudies-literature
Project description:A simple, safe, and effective technique of postop analgesia using wound perfusion with bupivacaine 0.25% via an indwelling intracatheter inserted in the depth of the wound was carried out on 25 ASA grade I/II patients of varying age groups reporting for a variety of surgical procedures. The first dose was given prior to shifting the patient from the OT. Subsequent doses were administered on patient demand basis. The intracatheter was kept in position for 48-72 hours postop. An analysis was made on the patients' pain relief using a visual analogue scale, dose/frequency of bupivacaine required, dose/type of supplemental analgesia needed, haemodynamic changes during infiltration, wound healing, and patient satisfaction. In this study only 12% of patients required opioids on Day One postoperatively. There were no adverse effects of infiltration either systemically or on wound healing, and all the patients had excellent postop analgesia.
| S-EPMC5532130 | biostudies-other
Project description:Understanding the pseudo-gap phase which opens in the under-doped regime of cuprate superconductors is one of the most enduring challenges of the physics of these compounds. A depletion in the electronic density of states is observed, which is gapping out part of the Fermi surface, leading to the formation of mysterious lines of massless excitations- the Fermi arcs. Here we give a new theoretical account of the physics of the pseudo-gap phase in terms of the emergence of local patches of particle-hole pairs generated by SU(2) symmetry fluctuations. The proliferation of these local patches accounts naturally for the robustness of the pseudo-gap phase to disturbances like disorder or magnetic field and is shown to gap out part of the Fermi surface, leading to the formation of the Fermi arcs. Most noticeably, we show that these patches induce a modulated charge distribution on the Oxygen atoms, in remarkable agreement with recent X-ray and STM observations.
| S-EPMC5471275 | biostudies-literature
Project description:Investigation of domestication footprints in three major Solanaceae species
| PRJEB26324 | ENA
Project description:Activity of cortical local neuronal populations fluctuates continuously, and a large proportion of these fluctuations are shared across populations of neurons. Here we seek organizational rules that link these two phenomena. Using neuronal activity, as identified by functional MRI (fMRI) and for a given voxel or brain region, we derive a single measure of full bandwidth brain-oxygenation-level-dependent (BOLD) fluctuations by calculating the slope, ?, for the log-linear power spectrum. For the same voxel or region, we also measure the temporal coherence of its fluctuations to other voxels or regions, based on exceeding a given threshold, ?, for zero lag correlation, establishing functional connectivity between pairs of neuronal populations. From resting state fMRI, we calculated whole-brain group-averaged maps for ? and for functional connectivity. Both maps showed similar spatial organization, with a correlation coefficient of 0.75 between the two parameters across all brain voxels, as well as variability with hodology. A computational model replicated the main results, suggesting that synaptic low-pass filtering can account for these interrelationships. We also investigated the relationship between ? and structural connectivity, as determined by diffusion tensor imaging-based tractography. We observe that the correlation between ? and connectivity depends on attentional state; specifically, ? correlated more highly to structural connectivity during rest than while attending to a task. Overall, these results provide global rules for the dynamics between frequency characteristics of local brain activity and the architecture of underlying brain networks.
| S-EPMC3632346 | biostudies-literature
Project description:Recent studies have drawn attention to the evolution of protein dynamics, in addition to sequence and structure, based on the premise structure-encodes-dynamics-encodes-function. Of interest is to understand how functional differentiation is accomplished while maintaining the fold, or how intrinsic dynamics plays out in the evolution of structural variations and functional specificity. We performed a systematic computational analysis of 26,899 proteins belonging to 116 CATH superfamilies. Characterizing cooperative mechanisms and convergent/divergent features that underlie the shared/differentiated dynamics of family members required a methodology that lends itself to efficient analyses of large ensembles of proteins. We therefore introduced, SignDy, an integrated pipeline for evaluating the signature dynamics of families based on elastic network models. Our analysis confirmed that family members share conserved, highly cooperative (global) modes of motion. Importantly, our analysis discloses a subset of motions that sharply distinguishes subfamilies, which lie in a low-to-intermediate frequency regime of the mode spectrum. This regime has maximal impact on functional differentiation of families into subfamilies, while being evolutionarily conserved among subfamily members. Notably, the high-frequency end of the spectrum also reveals evolutionary conserved features across and within subfamilies; but in sharp contrast to global motions, high-frequency modes are minimally collective. Modulation of robust/conserved global dynamics by low-to-intermediate frequency fluctuations thus emerges as a versatile mechanism ensuring the adaptability of selected folds and the specificity of their subfamilies. SignDy further allows for dynamics-based categorization as a new layer of information relevant to distinctive mechanisms of action of subfamilies, beyond sequence or structural classifications.
| S-EPMC6736388 | biostudies-literature
Project description:This study is aimed at investigating the characteristics of the spontaneous brain activity in patients with myotonic dystrophy type 1 (DM1). A total of 18 patients with DM1 and 18 healthy controls (HCs) were examined by resting-state functional MRI. Combined methods include amplitude of low-frequency fluctuations (ALFFs), the fractional amplitude of low-frequency fluctuations (fALFFs), and Wavelet transform-based ALFFs (Wavelet-ALFFs) with standardization, percent amplitude of fluctuation (PerAF) with/without standardization were applied to evaluate the spontaneous brain activity of patients with DM1. Compared with HCs, patients with DM1 showed decreased ALFFs and Wavelet-ALFFs in the bilateral precuneus (PCUN), angular gyrus (ANG), inferior parietal, but supramarginal and angular gyri (IPL), posterior cingulate gyrus (PCG), superior frontal gyrus, medial (SFGmed), middle occipital gyrus (MOG), which were mainly distributed in the brain regions of default mode network (DMN). Decreased ALFFs and Wavelet-ALFFs were also seen in bilateral middle frontal gyrus (MFG), inferior frontal gyrus, opercular part (IFGoperc), which were the main components of the executive control network (ECN). Patients with DM1 also showed decreased fALFFs in SFGmed.R, the right anterior cingulate and paracingulate gyri (ACGR), bilateral MFG. Reduced PerAF in bilateral PCUN, ANG, PCG, MOG, and IPLL as well as decreased PerAF without standardization in PCUNR and bilateral PCG also existed in patients with DM1. In conclusion, patients with DM1 had decreased activity in DMN and ECN with increased fluctuations in the temporal cortex and cerebellum. Decreased brain activity in DMN was the most repeatable and reliable with PCUN and PCG being the most specific imaging biomarker of brain dysfunction in patients with DM1.
| S-EPMC8703136 | biostudies-literature
Project description:BackgroundSouthern Taiwan has been a hotspot for dengue fever transmission since 1998. During 2014 and 2015, Taiwan experienced unprecedented dengue outbreaks and the causes are poorly understood. This study aims to investigate the influence of regional and local climate conditions on the incidence of dengue fever in Taiwan, as well as to develop a climate-based model for future forecasting.Methodology/principle findingsHistorical time-series data on dengue outbreaks in southern Taiwan from 1998 to 2015 were investigated. Local climate variables were analyzed using a distributed lag non-linear model (DLNM), and the model of best fit was used to predict dengue incidence between 2013 and 2015. The cross-wavelet coherence approach was used to evaluate the regional El Niño Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD) effects on dengue incidence and local climate variables. The DLNM results highlighted the important non-linear and lag effects of minimum temperature and precipitation. Minimum temperature above 23°C or below 17°C can increase dengue incidence rate with lag effects of 10 to 15 weeks. Moderate to high precipitation can increase dengue incidence rates with a lag of 10 or 20 weeks. The model of best fit successfully predicted dengue transmission between 2013 and 2015. The prediction accuracy ranged from 0.7 to 0.9, depending on the number of weeks ahead of the prediction. ENSO and IOD were associated with nonstationary inter-annual patterns of dengue transmission. IOD had a greater impact on the seasonality of local climate conditions.Conclusions/significanceOur findings suggest that dengue transmission can be affected by regional and local climatic fluctuations in southern Taiwan. The climate-based model developed in this study can provide important information for dengue early warning systems in Taiwan. Local climate conditions might be influenced by ENSO and IOD, to result in unusual dengue outbreaks.
| S-EPMC5456348 | biostudies-literature
Project description:Polymer networks are fundamental from cellular biology to plastics technology but their intrinsic inhomogeneity is masked by the usual ensemble-averaged measurements. Here, we construct direct maps of crosslinks-symbolic depiction of spatially-distributed elements highlighting their physical features and the relationships between them-in an actin network. We selectively label crosslinks with fluorescent markers, track their thermal fluctuations, and characterize the local elasticity and cross-correlations between crosslinks. Such maps display massive heterogeneity, reveal abundant anticorrelations, and may contribute to address how local responses scale up to produce macroscopic elasticity. Single-crosslink microscopy offers a general, microscopic framework to better understand crosslinked molecular networks in undeformed or strained states.
| S-EPMC6658493 | biostudies-literature