The Dynamic Brain in Action: Cortical Oscillations and Coordination Dynamics

Cortical oscillations are electrical activities with rhythmic and/or repetitive nature generated spontaneously and in response to stimuli. Study of cortical oscillations has become an area of converging interests since the last two decades and has deepened our understanding of its physiological basis across different behavioral states. Experimental and modeling work has taught us that there is a wide diversity of cellular and circuit mechanisms underlying the generation of cortical rhythms. A wildly diverse set of functions has pertained to synchronous oscillations but their significance in cognition should be better appraised in the more general framework of correlation between spike times of neurons. Oscillations are the core mechanism in adjusting neuronal interactions and shaping temporal coordination of neural activity. In the first part of this thesis, we review essential feature of cortical oscillations in membrane potentials and local field potentials recorded from turtle ex vivo preparation. Then we develop a simple computational model that reproduces the observed features. This modeling investigation suggests a plausible underlying mechanism for rhythmogenesis through cellular and circuit properties. The second part of the thesis is about temporal coordination dynamics quantified by signal and noise correlations. Here, again, we present a computational model to show how temporal coordination and synchronous oscillations can be sewn together. More importantly, what biophysical ingrediants are necessary for a network to reproduce the observed coordination dynamics

A Review on the Meaning of “Ruku” in the Verse of Wilayah from Sunni and Shi’ite Perspective

One of the important verses on the subject of Wilayah is Surah Al-Ma’idah: 55 known as the verse of Wilayah that has caused extensive exegetic arguments between Sunni and Shi’ite denominations. This noble verse is controversial due to different perspectives such as asbab al-Nuzul (occasions of revelation), the meaning of Wilayah, the interpretation of “Allazina Amanu”, the reason of plurality in “Allazina Amanu”, and so on. The interpretation of Ruku is one of the basic aspects of this verse which is influential on the comprehension of the other parts of the verse and about which there are serious controversies between Sunni and Shi’ite denominations. The present article critically and comparatively represents the viewpoints of Sunni and Shi’ite commentators on the meaning of ‘Ruku”. This comparative study explores critical views of the Sunnis and Shi’ites, thematic analysis of “Ruku” in the Qur’an in terms of historical review and sequence of Nuzul, as well as its revelatory interpretation -outward Ruku- and its inward interpretation that is humbleness.   Seyed Mahmood Tayeb Hoseini * Received: 5/3/2018   |   Accepted: 11/17/2018 Abstract One of the important verses on the subject of Wilayah is Surah Al-Ma’idah: 55 known as the verse of Wilayah that has caused extensive exegetic arguments between Sunni and Shi’ite denominations. This noble verse is controversial due to different perspectives such as asbab al-Nuzul (occasions of revelation), the meaning of Wilayah, the interpretation of “Allazina Amanu”, the reason of plurality in “Allazina Amanu”, and so on. The interpretation of Ruku is one of the basic aspects of this verse which is influential on the comprehension of the other parts of the verse and about which there are serious controversies between Sunni and Shi’ite denominations. The present article critically and comparatively represents the viewpoints of Sunni and Shi’ite commentators on the meaning of ‘Ruku”. This comparative study explores critical views of the Sunnis and Shi’ites, thematic analysis of “Ruku” in the Qur’an in terms of historical review and sequence of Nuzul, as well as its revelatory interpretation -outward Ruku- and its inward interpretation that is humbleness. Keywords Ruku in the Qur’an, Verse of Wilayah, Comparative Exegesis, Sequence of Nuzul (Revelation)         بازخوانی معنای «رکوع» در آیة ولایت ازمنظر فریقین سیدمحمود طیب‌حسینی* تاریخ ارسال: 13/02/97   |   تاریخ پذیرش: 26/08/97 چکیده یکی از آیه‌های مهم در موضوع امامت که میان دو فرقة اهل‌تسنن و شیعه بحث‌ها و اختلاف‌های گسترده‌ای در تفسیر آن درگرفته، آیة 55 سورة مائده مشهور به آیة ولایت است. این آیة شریفه از زوایا و بخش‌های مختلف همچون شأن نزول، معنا و مقصود ولایت، مقصود از «الذین آمنوا»، علت جمع آمدن «الذین آمنوا» و... قابل بحث است. یکی از بخش‌های اساسی این آیة شریفه که نقش مهمی در فهم سایر بخش‌های آن دارد و اختلافات جدی‌‌ای میان فرق اسلامی دربارة آن وجود دارد، بیان معنا و مقصود «رکوع» در آن است. در مقاله حاضر، به روش تطبیقی دیدگاه مفسران فریقین دربارة معنای «رکوع» نقل و نقد شده است. نقد دیدگاه مفسران شیعه و اهل‌تسنن، بررسی موضوعی واژة رکوع در قرآن براساس سیر تاریخی و ترتیب نزول آیات، و پیرو آن ادعای اینکه «رکوع» در این آیه یک معنای تنزیلی دارد که همان رکوع ظاهری است و یک معنای باطنی دارد و آن خضوع است، در این مطالعه تطبیقی بررسی می‌شود. کلیدواژگان رکوع در قرآن، آیة ولایت، علی، تفسیر تطبیقی، ترتیب نزول

Effect of different application strategies of universal adhesive used for immediate and delayed dentin sealing on the microtensile bond strength of self-adhesive resin cement to dentin with and without aging

Bond strength of indirect restorations is a very important issue that should be given special attention. Immediate dentin sealing (IDS) technique has been suggested in recent years. The aim of the present study was to investigate the effect of different

Towards developing an integrated index of access to dialysis facilities: A systematic review

Background: The equitable Access to Healthcare Services (AHS) constitutes one of the main priorities of the healthcare providers. Access to Dialysis Facilities (ADF) has an important impact on the renal dialysis patients. There are many spatial and non-spatial factors that potentially can affect ADF. Objectives: We aimed to review available literature on factors affecting ADF. We have also tried to identify knowledge gaps in current studies in order to use those elicited factors to cover these gaps in developing an integrated index of ADF. Methods: In May 2016, the literature was systematically searched using the following electronic databases: PubMed, Embase, Web of science, Scopus, Science Direct, and IEEE Xplore. A 3-step method to identify studies related to ADF was used. Study selection processes were performed by two independent reviewers. The quality of studies was assessed using a mixed approach scoring system. Results: Initially, 975 literature were identified searching the selected databases. After removing duplicates, study screening, and applying inclusion/exclusion criteria, 34 studies were identified for final review. Given the content of selected studies, three groups of studies were identified and 42 factors with the potential effect on ADF were determined. Conclusion: Our systematic research revealed that most of the factors with the potential effect on ADF are non-spatial. Such factors were underseen in many studies focusing mainly on the spatial dimensions of ADF. We recommended that all possible spatial and non-spatial factors together should be taken into account as part of an integrated index of ADF

Toward a Manifold Encoding Neural Responses

Understanding circuit properties from physiological data presents two challenges: (i) recordings do not reveal connectivity, and (ii) stimuli only exercise circuits to a limited extent. We address these challenges for the mouse visual system with a novel neural manifold obtained using unsupervised algorithms. Each point in our manifold is a neuron; nearby neurons respond similarly in time to similar parts of a stimulus ensemble. This ensemble includes drifting gratings and flows, i.e., patterns resembling what a mouse would “see” running through fields. Regarding (i), our manifold differs from the standard practice in computational neuroscience: embedding trials in neural coordinates. Topology matters: we infer that, if the circuit consists of separate components, the manifold is discontinuous (illustrated with retinal data). If there is significant overlap between circuits, the manifold is nearly-continuous (cortical data). Regarding (ii), most of the cortical manifold is not activated with conventional gratings, despite their prominence in laboratory settings. Our manifold suggests organizing cortical circuitry by a few specialized circuits for specific members of the stimulus ensemble, together with circuits involving ‘multi-stimuli’-responding neurons. To approach real circuits, local neighborhoods in the manifold are identified with actual circuit components. For retinal data, we show these components correspond to distinct ganglion cell types by their mosaic-like receptive field organization, while for cortical data, neighborhoods organize neurons by type (excitatory/inhibitory) and anatomical layer. In summary: the topology of neural organization reflects well the underlying anatomy and physiology of the retina and the visual cortex

Comparing potential spatial access with self-reported travel times and cost analysis to haemodialysis facilities in North-eastern Iran

End-stage renal disease patients regularly need haemodialysis three times a week. Their poor access to haemodialysis facilities is significantly associated with a high mortality rate. The present cross-sectional study aimed to measure the potential spatial access to dialysis services at a small area level (census tract level) in North Khorasan Province, Iran. The patients were interviewed to obtain their travel information. The two-step floating catchment area (2SFCA) method was used to measure the spatial accessibility of patients to the dialysis centres. The capacity of the dialysis centre was defined as the number of active dialysis facilities in each centre and the haemodialysis patients in each area were considered as the users of dialysis services. The travel cost from each patient’s residence to the haemodialysis facilities was visualized by the Kriging interpolation algorithm in the study area. Spatial accessibility to the dialysis centre was poor in the northern part of the study area. Fortunately, there were not many haemodialysis patients in that area. Patients’ travel costs were high in the northern areas compared to the rest of study area. We observed a statistically significant reverse correlation between the self-reported travel time and computed spatial accessibility (-0.570, P value <0.01, two-tailed spearman test). This study supports the notion that the 2SFCA method could be associated with revealed access time to dialysis facilities, especially in low traffic and in flat areas such as northern Khorasan. The mapping of patients’ distribution and interpolated travel cost to the haemodialysis facilities could help policymakers to allocate health resources to the areas where the need is greater

Comparing potential spatial access with self-reported travel times and cost analysis to haemodialysis facilities in north-eastern Iran

End-stage renal disease patients regularly need haemodialysis three times a week. Their poor access to haemodialysis facilities is significantly associated with a high mortality rate. The present cross-sectional study aimed to measure the potential spatial access to dialysis services at a small area level (census tract level) in North Khorasan Province, Iran. The patients were interviewed to obtain their travel information. The two-step floating catchment area (2SFCA) method was used to measure the spatial accessibility of patients to the dialysis centres. The capacity of the dialysis centre was defined as the number of active dialysis facilities in each centre and the haemodialysis patients in each area were considered as the users of dialysis services. The travel cost from each patient's residence to the haemodialysis facilities was visualized by the Kriging interpolation algorithm in the study area. Spatial accessibility to the dialysis centre was poor in the northern part of the study area. Fortunately, there were not many haemodialysis patients in that area. Patients' travel costs were high in the northern areas compared to the rest of study area. We observed a statistically significant reverse correlation between the self-reported travel time and computed spatial accessibility (-0.570, P value <0.01, two-tailed spearman test). This study supports the notion that the 2SFCA method could be associated with revealed access time to dialysis facilities, especially in low traffic and in flat areas such as northern Khorasan. The mapping of patients' distribution and interpolated travel cost to the haemodialysis facilities could help policymakers to allocate health resources to the areas where the need is greater.n. 931059 from Mashhad University of Medical Sciences, Iran

Prevalence of Mycoplasma genitalium and Mycoplasma hominis isolates among Women with Cervicitis Referred to Karaj Health Care Centers

Background and Objectives: Mycoplasma is a genus of bacteria often found in the normal flora of the mouth, respiratory system and urogenital tract; but potentially pathogenic species also exist which can cause serious respiratory and genital diseases in human including postpartum fever, pelvic inflammatory infections, and pyelonephritis. The aim of this study was to evaluate the prevalence of Mycoplasma genitalium and Mycoplasma hominis in women who referred to the health centers in Karaj and investigate the susceptibility of M. genitalium strains against Fluoroquinolone antibiotics.Materials &amp; Methods: Endocervical swabs were taken from 200 women with cervicitis. Nucleic Acid Amplification Tests (NAATs) were performed for detecting Mgpa gene in M. genitalium and RNH gene in M. hominis. Mutations in parC and gyrA genes, as well as antibiotic resistance, were studied in positive samples of M. genitalium.Results: 9 M. genitalium and 11 M. hominis positive samples were found among samples obtained from women with cervicitis. Positive samples of M.genitalium were examined for isolating the parC and gyrA genes. Six sequences of these genes were analyzed by MEGA5 software. Mutation in parC gene was observed in one sequence which %16 shows resistance.Conclusion: M. hominis and M. genitalium were detected in 5.5% and 4.5% of samples, respectively. Our findings showed a relatively medium prevalence of M. hominis and M. genitalium in women with cervicitis in Alborz province. The sequencing results of gyrA and parC genes in this study represent the occurrence of mutations which drive fluoroquinolones resistance. Therefore, further studies are necessary in this area and to overcome this problem irregular prescribing limited and antibiotic sensitivity patterns in treatment to be considered

Association between heavy metals and colon cancer: an ecological study based on geographical information systems in North-Eastern Iran

Background: Colorectal cancer has increased in Middle Eastern countries and exposure to environmental pollutants such as heavy metals has been implicated. However, data linking them to this disease are generally lacking. This study aimed to explore the spatial pattern of age-standardized incidence rate (ASR) of colon cancer and its potential association with the exposure level of the amount of heavy metals existing in rice produced in north-eastern Iran. Methods: Cancer data were drawn from the Iranian population-based cancer registry of Golestan Province, northeastern Iran. Samples of 69 rice milling factories were analysed for the concentration levels of cadmium, nickel, cobalt, copper, selenium, lead and zinc. The inverse distance weighting (IDW) algorithm was used to interpolate the concentration of this kind of heavy metals on the surface of the study area. Exploratory regression analysis was conducted to build ordinary least squares (OLS) models including every possible combination of the candidate explanatory variables and chose the most useful ones to show the association between heavy metals and the ASR of colon cancer. Results: The highest concentrations of heavy metals were found in the central part of the province and particularly counties with higher amount of cobalt were shown to be associated with higher ASR of men with colon cancer. In contrast, selenium concentrations were higher in areas with lower ASR of colon cancer in men. A significant regression equation for men with colon cancer was found (F(4,137) = 38.304, P < .000) with an adjusted R2 of 0.77. The predicted ASR of men colon cancer was − 58.36 with the coefficients for cobalt = 120.33; cadmium = 80.60; selenium = − 6.07; nickel = − 3.09; and zinc = − 0.41. The association of copper and lead with colon cancer in men was not significant. We did not find a significant outcome for colon cancer in women. Conclusion: Increased amounts of heavy metals in consumed rice may impact colon cancer incidence, both positively and negatively. While there were indications of an association between high cobalt concentrations and an increased risk for colon cancer, we found that high selenium concentrations might instead decrease the risk. Further investigations are needed to clarify if there are ecological or other reasons for these discrepancies. Regular monitoring of the amount of heavy metals in consumed rice is recommended.This study was supported by Golestan University of Medical Sciences (grant number of 90–10–1-30209)

Mapping 123 million neonatal, infant and child deaths between 2000 and 2017

Since 2000, many countries have achieved considerable success in improving child survival, but localized progress remains unclear. To inform efforts towards United Nations Sustainable Development Goal 3.2—to end preventable child deaths by 2030—we need consistently estimated data at the subnational level regarding child mortality rates and trends. Here we quantified, for the period 2000–2017, the subnational variation in mortality rates and number of deaths of neonates, infants and children under 5 years of age within 99 low- and middle-income countries using a geostatistical survival model. We estimated that 32% of children under 5 in these countries lived in districts that had attained rates of 25 or fewer child deaths per 1,000 live births by 2017, and that 58% of child deaths between 2000 and 2017 in these countries could have been averted in the absence of geographical inequality. This study enables the identification of high-mortality clusters, patterns of progress and geographical inequalities to inform appropriate investments and implementations that will help to improve the health of all populations