Quasi-periodic patterns of brain intrinsic activity coordinate the functional connections in humans

The brain is a complex self-organizing biophysical system and intrinsically very active. How such intrinsic activity organizes the brain in humans is widely being studied during resting-state using functional magnetic resonance imaging (rsfMRI) and the functional connectivity (FC) metric. FC, calculated as the Pearson correlation between rsfMRI timeseries from different brain areas, indicates coherent activity on average over time, and can reflect some spatial aspects of the brain’s intrinsic organization. For example, based on the FC profile of each area, the cerebral cortex can be parcellated into a few resting-state networks (RSNs) or exhibit a few functional connectivity gradients (FCGs). Brain is a complex system and exhibits varied dynamic spatiotemporal regimes of coherent activity, which are still poorly understood. A subset of such regimes should be giving rise to FC, yet they might entail significantly insightful aspects about the brain’s self-organizing processes, which cannot be captured by FC. Among such dynamic regimes is the quasi-periodic pattern (QPP), obtained by identifying and averaging similar ~20s-long segments of rsfMRI timeseries. QPP involves a cycle of activation and deactivation of different areas with different timings, such that the overall activity within QPP resembles RSNs and FCGs, suggesting QPP might be contributing to FC. To robustly detect multiple QPPs, method improvements were implemented and three primary QPPs were thoroughly characterized. Within these QPPs activity propagates along the functional gradients at the cerebral cortex and most subcortical regions, in a well-coordinated way, because of the consistencies and synchronies across all brain regions which reasonably accord with the consensus on the structural connections. Nuanced timing differences between regions and the closed flow of activity throughout the brain suggest drivers for these patterns. When three QPPs are removed from rsfMRI timeseries, FC within and particularly between RSNs remarkably reduces, illustrating their dominant contribution. Together, our results suggest a few recurring spatiotemporal patterns of intrinsic activity might be dominantly coordinating the functional connections across the whole brain and serving self-organization. These intrinsic patterns possibly interact with the external tasks, affecting performance, or might provide more sensitive biomarkers in certain disorders and diseases.Ph.D

Cytotoxic and Apoptotic Activities of Methanolic Subfractions of Scrophularia oxysepala

Herbs have played a positive role in medicine for thousands of years. In the current study, we investigated the cytotoxicity effects of Scrophularia oxysepala methanolic subfractions and the underlying mechanism responsible for cell death in human breast carcinoma (MCF-7 cells) and mouse fibrosarcoma (WEHI-164 cells). From 60% and 80% methanolic fractions, four subfractions (Fa, Fb, Fc, and Fd), yielded from size exclusion by Sephadex-LH20 column chromatography, were chosen. MTT assay revealed that all subfractions significantly reduced cell viability after 24 h and 36 h in a dose-dependent manner; it is worth noting that Fa and Fb subfractions had the highest cytotoxicity, with IC50 values of 52.9 and 61.2 μg/mL in MCF-7 at 24 h, respectively. ELISA, TUNEL, and DNA fragmentation assay revealed that antiproliferative effects of all subfractions were associated with apoptosis on cancer cells, without any significant effect on L929 normal cells. qRT-PCR data showed that, after 24 h treatment with IC50 concentrations of the subfractions, caspase-3 expression was increased in cancer cells while the expression of Bcl-2 was decreased. S. oxysepala methanolic subfractions induce apoptosis in MCF-7 and WEHI-164 cells and could be considered as a source of natural anticancer agents

Modeling and Efficient Verification of Broadcasting Actors

International audienceMany distributed systems use broadcast communication for various reasons such as saving energy or increasing throughput. However, the actor model for concurrent and distributed systems does not directly support this kind of communication. In such cases, a broadcast must be modeled as multiple unicasts which leads to loss of modularity and state space explosion for any non-trivial system. In this paper, we extend Rebeca, an actor-based model language, to support asynchronous anonymous message broadcasting. Then, we apply counter abstraction for reducing the state space which efficiently bypasses the constructive orbit problem by considering the global state as a vector of counters, one per each local state. This makes the model checking of systems possible without further considerations of symmetry. This approach is efficient for fully symmetric system like broadcasting environments. We use a couple of case studies to illustrate the applicability of our method and the way their state spaces are reduced in size

Assessment of Prevalence of Asymptomatic Bacteriuria and Antibiotic susceptibility and its Risk factors in pregnant women living in Sabzevar City from 2014 to 2015

Introduction: Asymptomatic bacteriuria is a common problem during pregnancy. Delayed diagnosis and treatment may end up in harmful events for both mother and fetus. Physiological changes of urinary system during pregnancy facilitate the growth of microorganisms and cause this infection. This study was performed with aim to evaluate the prevalence of asymptomatic bacteriuria and determine the antibiotic susceptibility and its risk factors in pregnant women. Methods: This cross-sectional study was performed on 220 pregnant women referred to Shahidan Mobini Hospital in Sabzevar in 2014-2015. Sterile urine sample of pregnant women was analyzed in terms of Full urine test and culture. Antibiogram of isolated bacteria was done with colony count greater than 100000 by Bauer-Kirby Disk Diffusion. Individual characteristics of the subjects were recorded in the checklist. Data were analyzed by SPSS software (version 19) and Chi-square test. P0.05). Most common isolated organisms were Escherichia coli and staphylococcus ureus. Antibiogram results showed that cotrimoxasol, nitroforantoin, ciproflouxasin and nalidixic acide are appropriate antibiotics for treatment of patients. Conclusion: Asymptomatic bacteriuria has favorable prevalence in Sabzevar city. In the screening of this situation, considering individual and social characteristics seems to be necessary

Quantitative and Comparative Assessment of Learning in a Tongue-Operated Computer Input Device

Tongue drive system (TDS) is a wireless, wearable assistive technology that enables individuals with severe motor impairments to access computers, drive wheelchairs, and control their environments using tongue motion. In this paper, we have evaluated the TDS performance as a computer input device in four tasks, commonly known as horizontal, vertical, center-out, and multidirectional rapid tapping, based on Fitts' law and ISO9241-9 Standard. Nine able-bodied subjects, who already had tongue piercing, participated in this trial over five sessions during 5 weeks, allowing us to study the TDS learning process and its current limiting factors. Subjects wore tongue rings made of titanium in the form of a barbell with a small rare-earth magnetic tracer hermetically sealed inside the upper ball. Participants performed the same tasks with a mouse (only in the first session) as a reference as well as a standard keypad for benchmarking. Six performance measures were considered, including throughput, error rate, and reaction time, all of these improved significantly from the first to the last session, and some of these plateaued over the course of the experiment. The comparison between tongue–TDS versus index-finger–keypad provides valuable insights into tongue human factors, which can lead the way in improving the usability of the TDS and similar tongue-operated assistive technologies

Quantitative and Comparative Assessment of Learning in a Tongue-Operated Computer Input Device–-Part II: Navigation Tasks

Tongue drive system (TDS) is a novel tongue-operated assistive technology (AT) for the mobility impaired, to empower them to access computers and drive powered wheelchairs (PWC) using their free voluntary tongue motion. We have evaluated the TDS performance in five sessions over 5–8 weeks to study the learning process in different tasks of computer access and PWC navigation on nine able-bodied subjects who already had tongue piercing and used our magnetic tongue studs throughout the trial. Computer access tasks included on-screen maze navigation and issuing random commands to measure the TDS information transfer rate. PWC navigation included driving through a ~50-m obstacle course using three control strategies. Some of the qualitative aspects of using the TDS were also evaluated based on the two Likert scale questionnaires, one of which was short (eight questions) and asked at the end of each session and the other one (46 questions) at the end of the trial. Included in this study was also a task to measure the tongue fatigue as a result of using the TDS continuously for a few hours. All performance measures showed significant improvement from the first to the second session as well as further gradual improvements throughout the rest of the sessions, suggesting a rapid learning process