In silico estimates of the free energy rates in growing tumor spheroids

The physics of solid tumor growth can be considered at three distinct size scales: the tumor scale, the cell-extracellular matrix (ECM) scale and the sub-cellular scale. In this paper we consider the tumor scale in the interest of eventually developing a system-level understanding of the progression of cancer. At this scale, cell populations and chemical species are best treated as concentration fields that vary with time and space. The cells have chemo-mechanical interactions with each other and with the ECM, consume glucose and oxygen that are transported through the tumor, and create chemical byproducts. We present a continuum mathematical model for the biochemical dynamics and mechanics that govern tumor growth. The biochemical dynamics and mechanics also engender free energy changes that serve as universal measures for comparison of these processes. Within our mathematical framework we therefore consider the free energy inequality, which arises from the first and second laws of thermodynamics. With the model we compute preliminary estimates of the free energy rates of a growing tumor in its pre-vascular stage by using currently available data from single cells and multicellular tumor spheroids.Comment: 27 pages with 5 figures and 2 tables. Figures and tables appear at the end of the pape

A survey thesis of the personal reading preferences of children in the intermediate grades

Thesis (Ed.M.)--Boston Universit

Causal vs. Noncausal Description of Nonlinear Wave Mixing; Resolving the Damping-Sign Controversy

Frequency-domain nonlinear wave mixing processes may be described either using response functions whereby the signal is generated after all interactions with the incoming fields, or in terms of scattering amplitudes where all fields are treated symetrically with no specific time ordering. Closed Green's function expressions derived for the two types of signals have different analytical properties. The recent controversy regarding the sign of radiative damping in the linear (Kramers Heisenberg) formula is put in a broader context

Deep learning with convolutional neural networks for decoding and visualization of EEG pathology

We apply convolutional neural networks (ConvNets) to the task of distinguishing pathological from normal EEG recordings in the Temple University Hospital EEG Abnormal Corpus. We use two basic, shallow and deep ConvNet architectures recently shown to decode task-related information from EEG at least as well as established algorithms designed for this purpose. In decoding EEG pathology, both ConvNets reached substantially better accuracies (about 6% better, ~85% vs. ~79%) than the only published result for this dataset, and were still better when using only 1 minute of each recording for training and only six seconds of each recording for testing. We used automated methods to optimize architectural hyperparameters and found intriguingly different ConvNet architectures, e.g., with max pooling as the only nonlinearity. Visualizations of the ConvNet decoding behavior showed that they used spectral power changes in the delta (0-4 Hz) and theta (4-8 Hz) frequency range, possibly alongside other features, consistent with expectations derived from spectral analysis of the EEG data and from the textual medical reports. Analysis of the textual medical reports also highlighted the potential for accuracy increases by integrating contextual information, such as the age of subjects. In summary, the ConvNets and visualization techniques used in this study constitute a next step towards clinically useful automated EEG diagnosis and establish a new baseline for future work on this topic.Comment: Published at IEEE SPMB 2017 https://www.ieeespmb.org/2017

Resolving the chemical substructure of Orion-KL

The Kleinmann-Low nebula in Orion (Orion-KL) is the nearest example of a high-mass star-forming environment. For the first time, we complemented 1.3 mm Submillimeter Array (SMA) interferometric line survey with IRAM 30 m single-dish observations of the Orion-KL region. Covering a 4 GHz bandwidth in total, this survey contains over 160 emission lines from 20 species (25 isotopologues), including 11 complex organic molecules (COMs). At a spatial resolution of 1200 AU, the continuum substructures are resolved. Extracting the spectra from individual substructures and providing the intensity-integrated distribution map for each species, we studied the small-scale chemical variations in this region. Our main results are: (1) We identify lines from the low-abundance COMs CH3COCH3 and CH3CH2OH, as well as tentatively detect CH3CHO and long carbon-chains C6H and HC7N. (2) We find that while most COMs are segregated by type, peaking either towards the hot core (e.g., N-bearing species) or the compact ridge (e.g., O-bearing species like HCOOCH3 and CH3OCH3), while the distributions of others do not follow this segregated structure (e.g., CH3CH2OH, CH3OH, CH3COCH3). (3) We find a second velocity component of HNCO, SO2, 34SO2, and SO lines, which may be associated with a strong shock event in the low-velocity outflow. (4) Temperatures and molecular abundances show large gradients between central condensations and the outflow regions, illustrating a transition between hot molecular core and shock-chemistry dominated regimes. Our observations of spatially resolved chemical variations in Orion-KL provide the nearest reference source for hot molecular core and outflow chemistry, which will be an important example for interpreting the chemistry of more distant HMSFRs.Comment: 51 pages, 17 figures, accepted on 12 March 2015 Dashed lines in Figure 10 of the published paper was missin

Do earplugs stop noise from driving critical care patients into delirium?

Quality sleep is a problem for the critically ill who are cared for in an environment where interventions night and day are common, staff members are constantly present in relatively high numbers, and treatment is accompanied by a range of changing warning tones and alarms and lights. These critical care units are generally designed without a focus on patient comfort, sleep, and rest and often lack access to appropriate natural daylight. To add to this problem, critical illness, particularly sepsis, disrupts circadian rhythms and sleep patterns, and disruption of circadian rhythms, in turn, impairs immunity and contributes to delirium. In a randomized controlled trial in the previous issue of Critical Care, Van Rompaey and colleagues have intervened to reduce noise, which is a key factor in this disruption, by having patients use earplugs at night. Delirium was assessed by using the NEECHAM (Neelon and Champagne) confusion scale, and sleep perception was assessed by patients' responses to a set of five questions. After the first night, patients reported a better sleep perception and the occurrence of delirium was reduced (hazard ratio of 0.47 for the development of delirium) or was delayed. The study did not quantify adequacy of pain control in post-surgical patients and used patient reporting to assess sleep. Whether patients were receiving respiratory or other organ support was not reported. The potential benefit of earplugs is an important practical finding that could be implemented in most intensive care units

Examining the effectiveness of the theory of planned behaviour in explaining exercise intention and behaviour during pregnancy: a meta-analysis

Background: Several studies have supported the efficacy and predictive utility of the Theory of Planned Behaviour (TPB; Ajzen 1991) in explaining a variety of behaviours including physical activity. However, the relative contribution of the theory’s components in describing intention and behaviour may differ depending on the context, time and population being studied. Such evidence is necessary to inform exercise advice and interventions aimed at pregnant women. Purpose: The purpose of this study was therefore to review the existing literature surrounding the application of the TPB in explaining exercise intentions and behaviour during pregnancy and to evaluate the magnitude of relationships between TPB constructs within this context. Method: Multiple search strategies yielded 99 potentially relevant studies of which 47 were assessed against the inclusion criteria. Finally, 7 studies, involving 777 pregnant women, were included in the analysis. Relationships identified among TPB constructs were subjected to a random-effects meta-analytic review using the Comprehensive Meta-Analysis (version 3.0) computer software package. Results: Results confirmed the existence of a medium to strong relationship between intention and behaviour (r = 0.44, P < 0.05, R2 = 19.36) and also supported the existence of a direct relationship between behaviour and perceived behavioural control (PBC; r = 0.45, P < 0.05, R2 = 20.25). Pregnant women’s attitude (r = 0.48, P < 0.05, R2 = 23.04) had the strongest association with their intention to be physically active. However, both PBC (r = 0.47, P < 0.05, R2 = 22.09) and subjective norm (r = 0.42, P < 0.05, R2 = 17.64) revealed similar relationships with intention. Conclusion: The study supports the TPB as a relevant conceptual framework for the investigation of exercise intentions and behaviours during pregnancy. PBC carried slightly more weight in explaining behaviour than did intention thereby suggesting that exercise during pregnancy is not a behaviour that is under women’s complete volitional control. Intention to exercise was influenced primarily by expectant mothers’ beliefs about the positive and negative consequences of doing so. Contrary to previous meta-analytic reports in the exercise domain, this study supported the relevance of subjective norm as a construct to investigate exercise intentions and behaviour in a pregnant population. The perceived social pressure to conform to other people’s opinion about physical activity during pregnancy may well be an important consideration for pregnant women. These findings present both researchers and practitioners with an opportunity for intervention and further research

Examining the effectiveness of the Theory of Planned Behaviour in predicting exercise intention and behaviour during pregnancy: Preliminary findings from a random effects meta-analysis

Several studies have supported the efficacy and predictive utility of the Theory of Planned Behaviour (TPB; Ajzen, 1991) in explaining a variety of behaviours including physical activity. However, the relative contribution of the theory’s components in describing intention and behaviour may differ depending on the context, time and population being studied. Such evidence is necessary to inform exercise advice and interventions aimed at pregnant women. The purpose of this study was therefore to review the existing literature surrounding the application of the TPB in explaining exercise intentions and behaviour during pregnancy and to evaluate the magnitude of relationships between TPB constructs within this context. Multiple search strategies yielded 99 potentially relevant studies of which 47 were assessed against the inclusion criteria. Finally, 7 studies, involving 777 pregnant women, were included in the analysis. Relationships identified among TPB constructs were subjected to a random-effects meta-analytic review using the Comprehensive Meta-Analysis (version 3.0) computer software package. Results confirmed the existence of a medium to strong relationship between intention and behaviour (r = .44, P < .05, R2 = 19.36) and also supported the existence of a direct relationship between behaviour and perceived behavioural control (PBC; r = .45, P < .05, R2 = 20.25). Pregnant women’s attitude (r = .48, P < .05, R2 = 23.04) had the strongest association with their intention to be physically active. However, both PBC (r = .47, P < .05, R2 = 22.09) and subjective norm (r = .42, P < .05, R2 = 17.64) revealed similar relationships with intention. The study supports the TPB as a relevant conceptual framework for the investigation of exercise intentions and behaviours during pregnancy. PBC carried slightly more weight in explaining behaviour than did intention thereby suggesting that exercise during pregnancy is not a behaviour that is under women’s complete volitional control. Intention to exercise was influenced primarily by expectant mothers’ beliefs about the positive and negative consequences of doing so. Contrary to previous meta-analytic reports in the exercise domain, this study supported the relevance of subjective norm as a construct to investigate exercise intentions and behaviour in a pregnant population. The perceived social pressure to conform to other people’s opinion about physical activity during pregnancy may well be an important consideration for pregnant women. These findings present both researchers and practitioners with an opportunity for intervention and further research