The Effect of Lower-Body Positive Pressure on the Cardiorespiratory Response at Rest and during Submaximal Running Exercise.

Anti-gravity treadmills facilitate locomotion by lower-body positive pressure (LBPP). Effects on cardiorespiratory regulation are unknown. Healthy men (30 ± 8 y, 178.3 ± 5.7 cm, 70.3 ± 8.0 kg; mean ± SD) stood upright ( javax.xml.bind.JAXBElement@57c008e9 = 10) or ran ( javax.xml.bind.JAXBElement@7a503138 = 9) at 9, 11, 13, and 15 km.h javax.xml.bind.JAXBElement@189f9fd6 (5 min stages) with LBPP (0, 15, 40 mmHg). Cardiac output (CO), stroke volume (SV), heart rate (HR), blood pressure (BP), peripheral resistance (PR), and oxygen uptake (VO javax.xml.bind.JAXBElement@270f0b82 ) were monitored continuously. During standing, LBPP increased SV [by +29 ± 13 (+41%) and +42 ± 15 (+60%) ml, at 15 and 40 mmHg, respectively ( javax.xml.bind.JAXBElement@705fd8ca < 0.05)] and decreased HR [by -15 ± 6 (-20%) and -22 ± 9 (-29%) bpm ( javax.xml.bind.JAXBElement@bfdfe08 < 0.05)] resulting in a transitory increase in CO [by +1.6 ± 1.0 (+32%) and +2.0 ± 1.0 (+39%) l.min javax.xml.bind.JAXBElement@6ff8b18e ( javax.xml.bind.JAXBElement@3074f4e8 < 0.05)] within the first seconds of LBPP. This was accompanied by a transitory decrease in end-tidal PO javax.xml.bind.JAXBElement@3e63f3a4 [by -5 ± 3 (-5%) and -10 ± 4 (-10%) mmHg ( javax.xml.bind.JAXBElement@5a8a47de < 0.05)] and increase in VO javax.xml.bind.JAXBElement@7054e9c0 [by +66 ± 53 (+26%) and +116 ± 64 (+46%) ml.min javax.xml.bind.JAXBElement@67908096 ( javax.xml.bind.JAXBElement@464fa113 < 0.05)], suggesting increased venous return and pulmonary blood flow. The application of LBPP increased baroreflex sensitivity (BRS) [by +1.8 ± 1.6 (+18%) and +4.6 ± 3.7 (+47%) at 15 and 40 mmHg LBPP, respectively javax.xml.bind.JAXBElement@4e73aab3 < 0.05]. After reaching steady-state exercise CO vs. VO javax.xml.bind.JAXBElement@19be4054 relationships remained linear with similar slope and intercept for each participant (mean javax.xml.bind.JAXBElement@7ac9e7c5 javax.xml.bind.JAXBElement@41b586b6 = 0.84 ± 0.13) while MAP remained unchanged. It follows that (1) LBPP affects cardiorespiratory integration at the onset of exercise; (2) at a given LBPP, once reaching steady-state exercise, the cardiorespiratory load is reduced proportionally to the lower metabolic demand resulting from the body weight support; (3) the balance between cardiovascular response, oxygen delivery to the exercising muscles and blood pressure regulation is maintained at exercise steady-state; and (4) changes in baroreflex sensitivity may be involved in the regulation of cardiovascular parameters during LBPP

Neuronal and glial prostaglandin D synthase isozymes in chick dorsal root ganglia: a light and electron microscopic immunocytochemical study.

Homogenates of chick dorsal root ganglia (DRG) and in vitro cultures of DRG neurons are known to synthesize prostaglandin (PG) D2. To specify the PGD synthase isozymes controlling PGD2 synthesis in DRG and to identify the DRG cells responsible for this synthesis, we applied polyclonal antibodies raised against rat brain or rat spleen PGD synthase isozymes to vibratome or cryostat slices of DRG previously fixed with a formaldehyde-lysine-periodate mixture and permeabilized with Triton X-100. The immunoreactivity indicating rat spleen PGD synthase, a glutathione (GSH)-requiring enzyme, was located in satellite cells encompassing particular large neurons of class A and in Schwann cells myelinating and enwrapping their initial axonal segments. In contrast, the immunoreactivity of rat brain PGD synthase, a GSH-independent enzyme, was restricted to particular ganglion cell perikarya: 33% of the DRG neurons were immunostained for rat brain PGD synthase, including 2% of large class A neurons and 40% of small class B neurons. Only 3.3% of rat brain PGD synthase-immunoreactive small B neurons coexpressed substance P, indicating that the immunoreactive neurons belong to the B1 subclass. By electron microscopy, 71 of 72 immunoreactive DRG cells were identified as small B neurons of the B1 subclass, and 71 of 77 B1 neurons were immunoreactive for rat brain PGD synthase. These results demonstrate that PGD2 formation in DRG is regulated by two isozymes: the GSH-requiring isozyme located in satellite and Schwann cells and the GSH-independent isozyme-confined to small B1 neurons

Personalization of learning process in Tutoring System Supported with the Semantic Web Technologies

Predmet istraživanja disertacije obuhvata  realizaciju  opšteg  modela tutorskog sistema za elektronsko učenje iz različitih domena  primenom  tehnologija semantičkog veba i primena tog modela za  izgradnju tutorskog sistema za učenje programskog jezika Java sa elementima personalizacije. Cilj disertacije je implementacija  i predstavljanje  svih  elemenata  tutorskog sistema za učenje programskog jezika Java  pomodu tehnologija semantičkog veba. Ovaj proces obuhvata kreiranje  osnovnih  gradivnih  ontologija  kao i  pravila za izvođenje konkretnih akcija kojim se postiže personalizacija nastavnog materijala.The subject of the dissertation includes the implementation of a conceptual model of tutoring system for e-learning in different domains using semantic web technologies and application of that model in a design of a tutoring system for personalised learning of Java programming language. The goal of the dissertation is the implementation and presentation of all elements of the tutoring system for learning the Java programming language using semantic web technologies. This process includes the creation of the fundamental building blocks of ontologies and rules for carrying out the actions for adaptation of teaching materials

Applying Recommender Systems and Adaptive Hypermedia for e-Learning Personalizatio

Learners learn differently because they are different -- and they grow more distinctive as they mature. Personalized learning occurs when e-learning systems make deliberate efforts to design educational experiences that fit the needs, goals, talents, and interests of their learners. Researchers had recently begun to investigate various techniques to help teachers improve e-learning systems. In this paper we present our design and implementation of an adaptive and intelligent web-based programming tutoring system -- Protus, which applies recommendation and adaptive hypermedia techniques. This system aims at automatically guiding the learner's activities and recommend relevant links and actions to him/her during the learning process. Experiments on real data sets show the suitability of using both recommendation and hypermedia techniques in order to suggest online learning activities to learners based on their preferences, knowledge and the opinions of the users with similar characteristics

Estimating the time scale and anatomical location of atrial fibrillation spontaneous termination in a biophysical model

Due to their transient nature, spontaneous terminations of atrial fibrillation (AF) are difficult to investigate. Apparently, confounding experimental findings about the time scale of this phenomenon have been reported, with values ranging from 1s to 1min. We propose a biophysical modeling approach to study the mechanisms of spontaneous termination in two models of AF with different levels of dynamical complexity. 8s preceding spontaneous terminations were studied and the evolution of cycle length and wavefront propagation were documented to assess the time scale and anatomical location of the phenomenon. Results suggest that termination mechanisms are dependent on the underlying complexity of AF. During simulated AF of low complexity, the total process of spontaneous termination lasted 3,200ms and was triggered in the left atrium 800ms earlier than in the right atrium. The last fibrillatory activity was observed more often in the right atrium. These asymmetric termination mechanisms in both time and space were not observed during spontaneous terminations of complex AF simulations, which showed less predictable termination patterns lasting only 1,600ms. This study contributes to the interpretation of previous clinical observations, and illustrates how computer modeling provides a complementary approach to study the mechanisms of cardiac arrhythmia

Incidence of Apoptosis in the Lymphoid Organs of Normal or Malaria Infected Mice is Decreased in CD18 and Urokinase - Receptor (UPAR, CD87) Deficient Mice

Incidence of apoptosis was investigated in the spleen and lymph nodes of +/+, CD18 -/- and urokinase receptor (uPAR, CD87) -/- mice, untreated or Plasmodium Berghei Anka (PbA) infected. In non infected mice, incidence of apoptosis was lower in the lymph nodes of CD18 -/- and uPAR -/- than in +/+ mice, as seen by FACS analysis to count the number of hypodiploid and Annexin-V binding cells. Infection of mice with PbA resulted in a marked increase in the size of spleen and lymph nodes 7–8 days after infection, which was slightly higher in uPAR -/- and CD18 -/- than in +/+ mice. PbA infection increased about 7 fold the incidence of apoptosis in the lymphoid organs of +/+, especially in the white pulp and germinal centers of the spleen and lymph nodes, while in contrast it was unchanged in PbA infected CD18 -/- or uPAR -/- mice. Serum IgG levels, and number of circulating leukocytes were significantly higher in both uPAR and CD18 -/- than in +/+ mice. These results indicate that the CD18 and uPAR surface molecules, which are known to be associated in the cell membrane, have an important influence upon the incidence of cell survival in both normal or stimulated lymphoid organs

Minimal window duration for accurate HRV recording in athletes

Heart rate variability (HRV) is non-invasive and commonly used for monitoring responses to training loads, fitness, or overreaching in athletes. Yet, the recording duration for aseries of RR-intervals varies from 1 to 15 min in the literature. The aim of the present work was to assess the minimum record duration to obtain reliableHRV results. RR-intervalsfrom 159 orthostatic tests (7 min supine, SU, followed by 6 min standing, ST) were analyzed. Reference windows were 4 min in SU (min 3–7) and 4 min in ST (min 9–13).Those windows were subsequently divided and the analyses were repeated on eight different fractioned windows: the first min (0–1), the second min (1–2), the third min (2–3),the fourth min (3–4), the first 2 min (0–2), the last 2 min (2–4), the first 3 min (0–3), and thelast 3 min (1–4). Correlation and Bland & Altman statistical analyses were systematically performed. The analysis window could be shortened to 0–2 instead of 0–4 for RMSSD only, whereas the 4-min window was necessary for LF and total power. Since there is a need for 1 min of baseline to obtain a steady signal prior the analysis window, we conclude that studies relying on RMSSD may shorten the windows to 3 min (=1+2)in SU or seated position only and to 6 min (=1+2 min SU plus 1+2 min ST) if there is an orthostatic test. Studies relying on time- and frequency-domain parameters need a minimum of 5 min (=1+4) min SU or seated position only but require 10 min (=1+4 minSU plus 1+4 min ST) for the orthostatic tes

Transfluthrin indoor air concentration and inhalation exposure during application of electric vaporizers

International audienceDifferent household insecticide applications via two electric vaporizers emitting transfluthrin were realized in a full-scale experimental room under controlled air exchange rate conditions. On-line high-time resolved measurements of the gas-phase concentrations of the active substance during and immediately after the spreading periods were performed with a High Sensitivity Proton-Transfer-Reaction Mass Spectrometer (HS-PTR-MS). Experimental and modelled data from the ConsExpo 4.0 software were also compared to evaluate the sources of differences. Different application scenarios were also compared. Averaged inhaled concentrations over 1h, 1week, and 5months were estimated to be 8.3, 1.8, and 1.8μg.m(-3), respectively. Corresponding margins of exposures range from 1000 to 10,000, claiming for the absence of effect. Dermal and dust ingestion pathways, although roughly estimated, seems being non-negligible. This claims for a more in-depth integrated risk assessment

Estimating the real-time respiratory rate from the ECG with a bank of notch filters

The respiratory rate is an important vital sign that needs to be monitored continuously in clinical and non-clinical health monitoring applications. It is commonly estimated from electrocardiogram (ECG)-derived respiratory waveforms such as the respiratory sinus arrhythmia~(RSA) and the ECG R peak amplitude~(RPA). Current methods combine respiratory information from these two waveforms but produce large delays in estimating the respiratory rate. In this work, the power of the outputs of a bank of order-3 FIR notch filters were used in an adaptive scheme to estimate in a real-time manner and with minimal delay the respiratory rate from the RSA and the RPA waveforms simultaneously. The algorithm was tested on the public Physionet Fantasia data set and compared to the state-of-the-art in terms of estimation accuracy and delay. It was shown that the proposed method provides more accurate estimates with smaller delays than those of the state-of-the-art