Signaling by FGF4 and FGF8 is required for axial elongation of the mouse embryo

AbstractFibroblast growth factor (FGF) signaling has been shown to play critical roles in vertebrate segmentation and elongation of the embryonic axis. Neither the exact roles of FGF signaling, nor the identity of the FGF ligands involved in these processes, has been conclusively determined. Fgf8 is required for cell migration away from the primitive streak when gastrulation initiates, but previous studies have shown that drastically reducing the level of FGF8 later in gastrulation has no apparent effect on somitogenesis or elongation of the embryo. In this study, we demonstrate that loss of both Fgf8 and Fgf4 expression during late gastrulation resulted in a dramatic skeletal phenotype. Thoracic vertebrae and ribs had abnormal morphology, lumbar and sacral vertebrae were malformed or completely absent, and no tail vertebrae were present. The expression of Wnt3a in the tail and the amount of nascent mesoderm expressing Brachyury were both severely reduced. Expression of genes in the NOTCH signaling pathway involved in segmentation was significantly affected, and somite formation ceased after the production of about 15–20 somites. Defects seen in the mutants appear to result from a failure to produce sufficient paraxial mesoderm, rather than a failure of mesoderm precursors to migrate away from the primitive streak. Although the epiblast prematurely decreases in size, we did not detect evidence of a change in the proliferation rate of cells in the tail region or excessive apoptosis of epiblast or mesoderm cells. We propose that FGF4 and FGF8 are required to maintain a population of progenitor cells in the epiblast that generates mesoderm and contributes to the stem cell population that is incorporated in the tailbud and required for axial elongation of the mouse embryo after gastrulation

Unsupervised Heart-rate Estimation in Wearables With Liquid States and A Probabilistic Readout

Heart-rate estimation is a fundamental feature of modern wearable devices. In this paper we propose a machine intelligent approach for heart-rate estimation from electrocardiogram (ECG) data collected using wearable devices. The novelty of our approach lies in (1) encoding spatio-temporal properties of ECG signals directly into spike train and using this to excite recurrently connected spiking neurons in a Liquid State Machine computation model; (2) a novel learning algorithm; and (3) an intelligently designed unsupervised readout based on Fuzzy c-Means clustering of spike responses from a subset of neurons (Liquid states), selected using particle swarm optimization. Our approach differs from existing works by learning directly from ECG signals (allowing personalization), without requiring costly data annotations. Additionally, our approach can be easily implemented on state-of-the-art spiking-based neuromorphic systems, offering high accuracy, yet significantly low energy footprint, leading to an extended battery life of wearable devices. We validated our approach with CARLsim, a GPU accelerated spiking neural network simulator modeling Izhikevich spiking neurons with Spike Timing Dependent Plasticity (STDP) and homeostatic scaling. A range of subjects are considered from in-house clinical trials and public ECG databases. Results show high accuracy and low energy footprint in heart-rate estimation across subjects with and without cardiac irregularities, signifying the strong potential of this approach to be integrated in future wearable devices.Comment: 51 pages, 12 figures, 6 tables, 95 references. Under submission at Elsevier Neural Network

Principles for Designing Context-Aware Applications for Physical Activity Promotion

Mobile devices with embedded sensors have become commonplace, carried by billions of people worldwide. Their potential to influence positive health behaviors such as physical activity in people is just starting to be realized. Two critical ingredients, an accurate understanding of human behavior and use of that knowledge for building computational models, underpin all emerging behavior change applications. Early research prototypes suggest that such applications would facilitate people to make difficult decisions to manage their complex behaviors. However, the progress towards building real-world systems that support behavior change has been much slower than expected. The extreme diversity in real-world contextual conditions and user characteristics has prevented the conception of systems that scale and support end-users’ goals. We believe that solutions to the many challenges of designing context-aware systems for behavior change exist in three areas: building behavior models amenable to computational reasoning, designing better tools to improve our understanding of human behavior, and developing new applications that scale existing ways of achieving behavior change. With physical activity as its focus, this thesis addresses some crucial challenges that can move the field forward. Specifically, this thesis provides the notion of sweet spots, a phenomenological account of how people make and execute their physical activity plans. The key contribution of this concept is in its potential to improve the predictability of computational models supporting physical activity planning. To further improve our understanding of the dynamic nature of human behavior, we designed and built Heed, a low-cost, distributed and situated self-reporting device. Heed’s single-purpose and situated nature proved its use as the preferred device for self-reporting in many contexts. We finally present a crowdsourcing system that leverages expert knowledge to write personalized behavior change messages for large-scale context-aware applications.PHDInformationUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/144089/1/gparuthi_1.pd

Cross-sectional associations between sleep duration, sedentary time, physical activity, and adiposity indicators among Canadian preschool-aged children using compositional analyses

Abstract Background Sleep duration, sedentary behaviour, and physical activity are three co-dependent behaviours that fall on the movement/non-movement intensity continuum. Compositional data analyses provide an appropriate method for analyzing the association between co-dependent movement behaviour data and health indicators. The objectives of this study were to examine: (1) the combined associations of the composition of time spent in sleep, sedentary behaviour, light-intensity physical activity (LPA), and moderate- to vigorous-intensity physical activity (MVPA) with adiposity indicators; and (2) the association of the time spent in sleep, sedentary behaviour, LPA, or MVPA with adiposity indicators relative to the time spent in the other behaviours in a representative sample of Canadian preschool-aged children. Methods Participants were 552 children aged 3 to 4 years from cycles 2 and 3 of the Canadian Health Measures Survey. Sedentary time, LPA, and MVPA were measured with Actical accelerometers (Philips Respironics, Bend, OR USA), and sleep duration was parental reported. Adiposity indicators included waist circumference (WC) and body mass index (BMI) z-scores based on World Health Organization growth standards. Compositional data analyses were used to examine the cross-sectional associations. Results The composition of movement behaviours was significantly associated with BMI z-scores (p = 0.006) but not with WC (p = 0.718). Further, the time spent in sleep (BMI z-score: γ sleep  = −0.72; p = 0.138; WC: γ sleep  = −1.95; p = 0.285), sedentary behaviour (BMI z-score: γ SB  = 0.19; p = 0.624; WC: γ SB  = 0.87; p = 0.614), LPA (BMI z-score: γ LPA  = 0.62; p = 0.213, WC: γ LPA  = 0.23; p = 0.902), or MVPA (BMI z-score: γ MVPA  = −0.09; p = 0.733, WC: γ MVPA  = 0.08; p = 0.288) relative to the other behaviours was not significantly associated with the adiposity indicators. Conclusions This study is the first to use compositional analyses when examining associations of co-dependent sleep duration, sedentary time, and physical activity behaviours with adiposity indicators in preschool-aged children. The overall composition of movement behaviours appears important for healthy BMI z-scores in preschool-aged children. Future research is needed to determine the optimal movement behaviour composition that should be promoted in this age group

Estimation of sleep recovery in shift working long-haul truck drivers – A heart rate variability based study

Prolonged work hours, shortened and irregular sleep patterns often leads to inadequate recovery in shift workers resulting in increased sleepiness or fatigue during the day. Heart rate and heart rate variability (HRV) have been often used in occupational health studies to examine sleep quality and recovery. The aim of the current study was to determine the factors affecting the recovery process in shift working long-haul truck drivers and to as-sess the impact different shifts have on the drivers’ sleep health. Of the recruited volunteers, data collected from 38 volunteers (Age: 38.46 ± 10.89 years) satisfied the inclusion criteria for this study. Driver demographics and background questionnaires were obtained prior to measurements. R-R intervals and actigraphy data were collected for three intensive measurement days (non-night shift, night shift and lei-sure day) and subjective measures of sleep quality, recorded on the sleep-diary, were used for the analyses. Several time- and frequency-domain HRV indices were calculated in 10-minute segments and averaged on an hourly basis and for the entire duration of sleep. All tests for statistical significance was conducted on a within-subject basis. Comparison of HRV indices over the entire sleep duration recorded on different in-tensive measurement days revealed no significant differences except for LF/HF ratio (Lei-sure day vs. Night shift, p <0.05). Sleep duration and efficiency were significantly lower on duty days. Regression analyses indicated VLF power was strong predictor of recovery and 31% of the outcome was influenced by explanatory factors. SDNN (r = 0.555, ad-justed r2 = 0.248, F(9, 92) = 5.166, p <0.001), RMSSD (r = 0.414, adjusted r2 = 0.131, F(9.92) = 4.229, p <0.05) and HF power (r = 0.460, adjusted r2 = 0.165, F(9.92) = 4.526, p <0.001) were significantly associated with age and sleep duration. Short-term variabil-ity indices, RMSSD and HF power, were moderately influenced by diurnal variations. The results suggest that despite the fact that shift type does not have any direct con-sequences on sleep recovery, the odd work hours and irregular sleep schedules pose an indirect effect. The truncated sleep length, especially seen after night shift work, have been significantly associated with the impaired recovery and is contributed to by other short-term (diurnal variations) and long-term (ageing) factors. These results provide a basis for planning shift schedules such that direct or indirect manifestations of shift type-related influence on recovery are mitigated

Comparison of image quality of split-bolus computed tomography versus dual-phase computed tomography in abdominal trauma

Purpose: To compare the image quality in single-pass split-bolus abdominal computed tomography (CT) and conventional biphasic CT in abdominal trauma patients. Material and methods: Sixty-six consecutive abdominal trauma patients referred for CT were randomised into 2 groups: the study group (n = 33), scanned using the split-bolus technique; and the control group (n = 33), scanned using the conventional biphasic technique. CT image quality was analysed subjectively by 2 observers based on a 5-point Likert scale. The images were also analysed quantitatively for attenuation values achieved by region of interest (ROI) placements in major arteries, veins, and solid organs. In addition, the radiation dose in terms of the dose length product (DLP) was compared between the 2 groups. Results: The image quality in both groups ranged from good to excellent in most cases. There was no statistically significant difference in subjective image quality in both the groups as assessed by Likert score. Attenuation values in solid organs and major venous structures were significantly higher in the split-bolus group (p < 0.001). Arterial attenuation values were significantly higher in the control group (p < 0.001), but diagnostic levels were achieved in all patients. There was a reduction of 31.1% in DLP in the split-bolus group. Conclusions: The split-bolus technique offers comparable image quality and higher solid organ and venous enhancement than conventional biphasic protocol at a reduced radiation dose

Ionization Constants of Some Hydroxycoumarins in Dioxane-Water & Ethanol- Water Media

126-12

Unilateral absence of pulmonary artery: a radiographically occult cause of life-threatening hemoptysis

Unilateral absence or agenesis of pulmonary artery (UAPA) is a rare congenital abnormality with an estimated prevelance of 1 in 2,00,000 adults. The entity occurs commonly in association with other congenital heart diseases like septal defects or patent ductus arteriosus. The condition usually runs a benign clinical course with patients usually presenting clinically in adulthood with history of recurrent respiratory tract infections. Two such patients presented with recurrent respiratory tract infections, breathlessness and hemoptysis. The chest radiograph of first patient was reported as normal in the referring hospital, while that of second patient showed volume loss in left lung. CT Pulmonary Angiography (CTPA) was then performed which demonstrated the absence of right and left pulmonary arteries respectively in the first and second patients. Pulmonary artery branches were reformed distally by multiple collaterals arising from systemic arteries. The entire spectrum, including embryology, imaging features and management of UAPA are discussed. UAPA remains a potential cause for life-threatening hemoptysis, due to extensive collateralization associated with the condition. It is important for radiologists to be aware of this uncommon entity in order to suspect it on a routine chest radiograph, diagnose it and map associated collaterals on CTPA and also embolize the bleeding collaterals

An observational study of the healing time, associated factors, and complications during non-operative management of patients with blunt abdominal trauma

Background: Non-operative management (NOM) has shown success in the management of cases of blunt abdominal trauma (BAT), especially in hemodynamically stable patients, even if there is a higher grade of injury.Objectives: The aim of this study was to determine the healing rate with NOM and associated risk factors of non-healing in patients with BAT.Methods: This prospective study was conducted on 20 hemodynamically stable patients of BAT who were treated in a tertiary care hospital by NOM. Clinical monitoring and biochemical investigations were done. The patients were followed-up for three months. The outcome measures were the average time of healing and complications. A p-value less than 0.05 was considered statistically significant.Results: The mean age of the patients was 24.5 years with 18 (90%) males and 2(10%) females. Nine patients (45%) had isolated liver injury, 8 (40%) had isolated splenic injury, 1 (5%) had isolated left renal injury, 1 (5%) had combined liver and splenic injury and 1 (5%) had combined liver and right renal injury. At 3 months of follow-up, 16 (80%) cases showed complete healing, 3(15%) showed incomplete healing and 1 (5%) patient with grade 4 splenic injury had failure of NOM. On performing univariate regression analysis, grade 3/4 was an independent risk factor of non-healing with an odds ratio of 5.667.Conclusion: In conclusion, NOM appears to be a safe and effective management protocol for patients with BAT, provided regular follow-ups and monitoring are done