Classifying Retinal Ganglion Cells for Bionic Vision

Current retinal implants implement pulsate stimuli to activate the neural circuits of the retina. This type of stimulation can activate antagonist retinal pathways which lead to the improper perception of the visual scene. Developing a precise stimulation strategy with the ability to preferentially target retinal neural circuits is one of the alternative methods to improve the accuracy of restored vision. Previous studies tried to decipher the electrical properties of different retina ganglion cell (RGC) types by applying electrical Gaussian noise and estimating the electrical input filter of the cells. Sekhar et al reported that ON and OFF cells have different electrical input filters. In this study, we aimed to pursue the same goal by using a similar approach to assess the electrical profiles for a wider range of ganglion cell types. We implemented an array of visual stimuli along with an electrical noise stimulus to fully characterize the light and electrical response properties of both healthy and degenerated retina ganglion cells

Estimating the maximum earthquake magnitude in the Iranian Plateau

The Iranian Plateau has been subjected to destructive earthquakes throughout its history. Reliable assessment of the seismic hazard in this earthquake-prone region is therefore essential. Our study focuses on estimating the maximum earthquake magnitude as one of the main parameters of seismic hazard analysis. We implemented two quantitative approaches, namely, probabilistic and deterministic. The probabilistic method allows combining the historical (i.e. incomplete) and the instrumental parts of a catalogue with different levels of completeness and considers the uncertainties in earthquake magnitude determination. In this study, we used a unified, declustered, and complete catalogue of earthquakes in Iran, covering the period from the fourth century BC to 2019. We calculated the maximum possible magnitudes for hundreds of grid points by using the seismicity data in a 200-km radial region around each grid point. The maximum possible earthquake was observed to vary between 6.0 and 8.2, and the highest values were found in the Alborz-Azarbayejan seismotectonic province, Kopeh-Dagh, central east Iran, Makran, and the southeast Zagros. The lowest mmax values were found in the Persian Gulf, Arabian Platform, Esfahan-Sirjan region, and the Dasht-e-Kavir Desert in central Iran. As a second part to this study, we calculated the maximum credible earthquakes for 1103 identified major faults by using five empirical magnitude-scaling relationships. Our results were consistent with both the observed earthquakes and the seismic potential of the various seismogenic zones of Iran. The study results can be used in future seismic hazard analyses and have fundamental implications for mitigating seismic risk in Iran.http://link.springer.com/journal/10950hj2022Geolog

THE THEORY OF CONSTRAINTS: A COMPARATIVE ASSESSMENT

ABSTRACT This paper examines in detail the relative utility of the Theory of Constraints compared to traditional management accounting approaches to resource utilisation in aiding decisionmaking. It also considers the propagation and evolution of the Theory of Constraints and critically examines the response it has generated in the accounting and management literature. The continuing survival of cost accounting in the face of frequent assaults similar to Goldratt's may in part be due to the ability of the discipline to adapt its practices to integrate the mandated improvements into practice and educational curricula. One example is the Theory of Constraints itself an

Estrogen and Progesterone Replacement Therapy Prevent Methamphetamine-Induced Synaptic Plasticity Impairment in Ovariectomized Rats

Background: Methamphetamine (METH) is one of the most popular psychostimulants which produce long lasting learning and memory impairment. Previous studies have indicated that estrogen and progesterone replacement therapy attenuate cognitive impairment against a wide array of neurodegenerative diseases. Present study was designed to figure out the effects of estrogen, progesterone alone or in combination, on early long-term potentiation (E-LTP) at the cornu ammonis (CA1) area of the hippocampus in METH-exposed ovariectomized (OVX) rat.Methods: Twenty-one days after ovariectomy, the OVX rats received vehicle, estrogen [1 mg/kg, intraperitoneal (IP)] or progesterone (8 mg/kg, IP) and co-administration of estrogen plus progesterone during 14 consecutive days. On the 28th day, animals were exposed to neurotoxic METH regimens [four injections 6 mg/kg, subcutaneous (SC), 2 h intervals] 30 min after the hormones replacement. Finally, we investigated the effect of those ovarian hormones on synaptic plasticity using in vivo extracellular recording in the CA1 area of the hippocampus 2 days after last treatment.Findings: The findings showed that the induction and maintenance phase of E-LTP was impaired in the METH exposed animals compared to the saline group. Data from this study demonstrated that treatment with estrogen and progesterone showed a significant facilitation for induction and enhancement of the maintenance of LTP in animals that received METH. In addition, co-administration of estrogen plus progesterone did not significantly affect the hippocampal synaptic plasticity in METH-exposed OVX rats in comparison with METH-exposed animals that received vehicle injections.Conclusion: The present findings provide new insight about treatment with ovarian hormones on synaptic plasticity deficits induced by METH

Global burden of 369 diseases and injuries in 204 countries and territories, 1990–2019: a systematic analysis for the Global Burden of Disease Study 2019

Background: In an era of shifting global agendas and expanded emphasis on non-communicable diseases and injuries along with communicable diseases, sound evidence on trends by cause at the national level is essential. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) provides a systematic scientific assessment of published, publicly available, and contributed data on incidence, prevalence, and mortality for a mutually exclusive and collectively exhaustive list of diseases and injuries. Methods: GBD estimates incidence, prevalence, mortality, years of life lost (YLLs), years lived with disability (YLDs), and disability-adjusted life-years (DALYs) due to 369 diseases and injuries, for two sexes, and for 204 countries and territories. Input data were extracted from censuses, household surveys, civil registration and vital statistics, disease registries, health service use, air pollution monitors, satellite imaging, disease notifications, and other sources. Cause-specific death rates and cause fractions were calculated using the Cause of Death Ensemble model and spatiotemporal Gaussian process regression. Cause-specific deaths were adjusted to match the total all-cause deaths calculated as part of the GBD population, fertility, and mortality estimates. Deaths were multiplied by standard life expectancy at each age to calculate YLLs. A Bayesian meta-regression modelling tool, DisMod-MR 2.1, was used to ensure consistency between incidence, prevalence, remission, excess mortality, and cause-specific mortality for most causes. Prevalence estimates were multiplied by disability weights for mutually exclusive sequelae of diseases and injuries to calculate YLDs. We considered results in the context of the Socio-demographic Index (SDI), a composite indicator of income per capita, years of schooling, and fertility rate in females younger than 25 years. Uncertainty intervals (UIs) were generated for every metric using the 25th and 975th ordered 1000 draw values of the posterior distribution. Findings: Global health has steadily improved over the past 30 years as measured by age-standardised DALY rates. After taking into account population growth and ageing, the absolute number of DALYs has remained stable. Since 2010, the pace of decline in global age-standardised DALY rates has accelerated in age groups younger than 50 years compared with the 1990–2010 time period, with the greatest annualised rate of decline occurring in the 0–9-year age group. Six infectious diseases were among the top ten causes of DALYs in children younger than 10 years in 2019: lower respiratory infections (ranked second), diarrhoeal diseases (third), malaria (fifth), meningitis (sixth), whooping cough (ninth), and sexually transmitted infections (which, in this age group, is fully accounted for by congenital syphilis; ranked tenth). In adolescents aged 10–24 years, three injury causes were among the top causes of DALYs: road injuries (ranked first), self-harm (third), and interpersonal violence (fifth). Five of the causes that were in the top ten for ages 10–24 years were also in the top ten in the 25–49-year age group: road injuries (ranked first), HIV/AIDS (second), low back pain (fourth), headache disorders (fifth), and depressive disorders (sixth). In 2019, ischaemic heart disease and stroke were the top-ranked causes of DALYs in both the 50–74-year and 75-years-and-older age groups. Since 1990, there has been a marked shift towards a greater proportion of burden due to YLDs from non-communicable diseases and injuries. In 2019, there were 11 countries where non-communicable disease and injury YLDs constituted more than half of all disease burden. Decreases in age-standardised DALY rates have accelerated over the past decade in countries at the lower end of the SDI range, while improvements have started to stagnate or even reverse in countries with higher SDI. Interpretation: As disability becomes an increasingly large component of disease burden and a larger component of health expenditure, greater research and developm nt investment is needed to identify new, more effective intervention strategies. With a rapidly ageing global population, the demands on health services to deal with disabling outcomes, which increase with age, will require policy makers to anticipate these changes. The mix of universal and more geographically specific influences on health reinforces the need for regular reporting on population health in detail and by underlying cause to help decision makers to identify success stories of disease control to emulate, as well as opportunities to improve. Funding: Bill & Melinda Gates Foundation. © 2020 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 licens

Global, regional, and national burden of disorders affecting the nervous system, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021

BackgroundDisorders affecting the nervous system are diverse and include neurodevelopmental disorders, late-life neurodegeneration, and newly emergent conditions, such as cognitive impairment following COVID-19. Previous publications from the Global Burden of Disease, Injuries, and Risk Factor Study estimated the burden of 15 neurological conditions in 2015 and 2016, but these analyses did not include neurodevelopmental disorders, as defined by the International Classification of Diseases (ICD)-11, or a subset of cases of congenital, neonatal, and infectious conditions that cause neurological damage. Here, we estimate nervous system health loss caused by 37 unique conditions and their associated risk factors globally, regionally, and nationally from 1990 to 2021.MethodsWe estimated mortality, prevalence, years lived with disability (YLDs), years of life lost (YLLs), and disability-adjusted life-years (DALYs), with corresponding 95% uncertainty intervals (UIs), by age and sex in 204 countries and territories, from 1990 to 2021. We included morbidity and deaths due to neurological conditions, for which health loss is directly due to damage to the CNS or peripheral nervous system. We also isolated neurological health loss from conditions for which nervous system morbidity is a consequence, but not the primary feature, including a subset of congenital conditions (ie, chromosomal anomalies and congenital birth defects), neonatal conditions (ie, jaundice, preterm birth, and sepsis), infectious diseases (ie, COVID-19, cystic echinococcosis, malaria, syphilis, and Zika virus disease), and diabetic neuropathy. By conducting a sequela-level analysis of the health outcomes for these conditions, only cases where nervous system damage occurred were included, and YLDs were recalculated to isolate the non-fatal burden directly attributable to nervous system health loss. A comorbidity correction was used to calculate total prevalence of all conditions that affect the nervous system combined.FindingsGlobally, the 37 conditions affecting the nervous system were collectively ranked as the leading group cause of DALYs in 2021 (443 million, 95% UI 378–521), affecting 3·40 billion (3·20–3·62) individuals (43·1%, 40·5–45·9 of the global population); global DALY counts attributed to these conditions increased by 18·2% (8·7–26·7) between 1990 and 2021. Age-standardised rates of deaths per 100 000 people attributed to these conditions decreased from 1990 to 2021 by 33·6% (27·6–38·8), and age-standardised rates of DALYs attributed to these conditions decreased by 27·0% (21·5–32·4). Age-standardised prevalence was almost stable, with a change of 1·5% (0·7–2·4). The ten conditions with the highest age-standardised DALYs in 2021 were stroke, neonatal encephalopathy, migraine, Alzheimer's disease and other dementias, diabetic neuropathy, meningitis, epilepsy, neurological complications due to preterm birth, autism spectrum disorder, and nervous system cancer.InterpretationAs the leading cause of overall disease burden in the world, with increasing global DALY counts, effective prevention, treatment, and rehabilitation strategies for disorders affecting the nervous system are needed

Electrical Input Filters of Ganglion Cells in Wild Type and Degenerating rd10 Mouse Retina as a Template for Selective Electrical Stimulation

Bionic vision systems are currently limited by indiscriminate activation of all retinal ganglion cells (RGCs)– despite the dozens of known RGC types which each encode a different visual message. Here, we use spike-triggered averaging to explore how electrical responsiveness varies across RGC types toward the goal of using this variation to create type-selective electrical stimuli. A battery of visual stimuli and a randomly distributed sequence of electrical pulses were delivered to healthy and degenerating (4-week-old rd10) mouse retinas. Ganglion cell spike trains were recorded during stimulation using a 60-channel microelectrode array. Hierarchical clustering divided the recorded RGC populations according to their visual and electrical response patterns. Novel electrical stimuli were presented to assess type-specific selectivity. In healthy retinas, responses fell into 35 visual patterns and 14 electrical patterns. In degenerating retinas, responses fell into 12 visual and 23 electrical patterns. Few correspondences between electrical and visual response patterns were found except for the known correspondence of ON visual type with upward deflecting electrical type and OFF cells with downward electrical profiles. Further refinement of the approach presented here may yet yield the elusive nuances necessary for type-selective stimulation. This study greatly deepens our understanding of electrical input filters in the context of detailed visual response characterization and includes the most complete examination yet of degenerating electrical input filters

The effect of four weeks high intensity interval training (HIIT) and aerobic training on troponin T content in healthy male Wistar rats myocardial tissue

Background Objectives: Cardiac troponin as a marker of heart, play a vital role in the diagnosis of heart disease. The purpose of this study was to assess the effect of four weeks high intensity interval training (HIIT) and aerobic training on troponin T content in healthy male rats� myocardial tissue.Materials & Methods: In this study, 36 Wistar rats 2 months with an average weight 180±20 were selected and randomly assigned divided into three groups, control (n=12), HIIT (n=12), and aerobic (n=12) groups; experimental group 5 days a week in accordance with their training program for 4 weeks to exercise. After 4 weeks, ANOVA test and Bonferroni post hoc test were used for analysis.Results: The results showed a no significant difference between the mean troponin T HIIT exercise and control groups. Troponin T is also a no significant difference between the Aerobic training and control groups.Conclusions: Based on the findings of troponin T in none of the groups had no significant change, It seems that exercise HIIT and Aerobic training with duration of 4 weeks do not damage the heart tissue