Spatial differences in corneal electroretinogram potentials measured in rat with a contact lens electrode array

PURPOSE: It has been known for several decades that the magnitude of the corneal electroretinogram (ERG) varies with position on the eye surface, especially in the presence of focal or asymmetric stimuli or retinal lesions. However, this phenomenon has not been well-characterized using simultaneous measurements at multiple locations on the cornea. This work provides the first characterization of spatial differences in the ERG across the rat cornea. METHODS: A contact lens electrode array was employed to record ERG potentials at 25 corneal locations simultaneously following brief full-field flash stimuli in normally sighted Long-Evans rats. These multi-electrode electroretinogram (meERG) responses were analyzed for spatial differences in a-wave and b-wave amplitudes and implicit times. RESULTS: Spatially distinct ERG potentials could be recorded reliably. Comparing relative amplitudes across the corneal locations suggested a slight non-uniform distribution when using full-field, near-saturating stimuli. Amplitudes of a- and b-waves were approximately 3 % lower in the inferior quadrant than in the superior quadrant of the cornea. CONCLUSIONS: The present results comprise the start of the first normative meERG database for rat eyes and provide a basis for comparison of results from eyes with functional deficit. Robust measures of spatial differences in corneal potentials will also support optimization and validation of computational source models of the ERG. To fully utilize the information contained in the meERG data, a detailed understanding of the roles of the many determinants of local corneal potentials will eventually be required

Intelligent control and security of fog resources in healthcare systems via a cognitive fog model

There have been significant advances in the field of Internet of Things (IoT) recently, which have not always considered security or data security concerns: A high degree of security is required when considering the sharing of medical data over networks. In most IoT-based systems, especially those within smart-homes and smart-cities, there is a bridging point (fog computing) between a sensor network and the Internet which often just performs basic functions such as translating between the protocols used in the Internet and sensor networks, as well as small amounts of data processing. The fog nodes can have useful knowledge and potential for constructive security and control over both the sensor network and the data transmitted over the Internet. Smart healthcare services utilise such networks of IoT systems. It is therefore vital that medical data emanating from IoT systems is highly secure, to prevent fraudulent use, whilst maintaining quality of service providing assured, verified and complete data. In this paper, we examine the development of a Cognitive Fog (CF) model, for secure, smart healthcare services, that is able to make decisions such as opting-in and opting-out from running processes and invoking new processes when required, and providing security for the operational processes within the fog system. Overall, the proposed ensemble security model performed better in terms of Accuracy Rate, Detection Rate, and a lower False Positive Rate (standard intrusion detection measurements) than three base classifiers (K-NN, DBSCAN and DT) using a standard security dataset (NSL-KDD)

Work Related Burden of Stress among Emergency Medical Service Personnel

Introduction: The staff of pre-hospital emergency medical service experience many stresses daily in the frontline of emergency responses. Critical conditions and trying to save patients’ lives make operation difficult for emergency medical technicians. The burden of stress in this job group is related with critical incidents, and functional and emotional problems that are the result of the rate of exposure and the intensity of the stressor. Methods: In this descriptive-correlation study, 320 technicians working in pre-hospital emergency bases participated. To gather data, stress burden evaluation questionnaire, which was the result of rate of exposure to stressors, was used. Data were analyzed using SPSS statistical software and descriptive and inferential statistics. Results: In the present study, the most important causes of burden of stress were reported to be environmental occupational factors and patient-related factors. Mean and standard deviation of stress burden was 8.70 ± 3.61. Working with trauma patients, unrealistic expectations of the patient or their relatives, and driving in critical conditions and resuscitation of patients inflicted the highest burden of stress upon the staff. In this study, the mean score of stressor intensity was higher than the mean score of exposure to stressors and a significant correlation was seen between the rate of stress burden with number of operations, educational degree, emergency bases, and status of employment. Conclusion: Proper identification of stressors in terms of prevalence and intensity, leads to better understanding of these factors in pre-hospital emergency and can be of great help in prevention and control of stress burden among emergency medical service staff

بار استرس مرتبط با عملیات اورژانس در تکنسین های فوریت های پزشکی

Introduction: The staff of pre-hospital emergency medical service experience many stresses daily in the frontline of emergency responses. Critical conditions and trying to save patients’ lives make operation difficult for emergency medical technicians. The burden of stress in this job group is related with critical incidents, and functional and emotional problems that are the result of the rate of exposure and the intensity of the stressor. Methods: In this descriptive-correlation study, 320 technicians working in pre-hospital emergency bases participated. To gather data, stress burden evaluation questionnaire, which was the result of rate of exposure to stressors, was used. Data were analyzed using SPSS statistical software and descriptive and inferential statistics. Results: In the present study, the most important causes of burden of stress were reported to be environmental occupational factors and patient-related factors. Mean and standard deviation of stress burden was 8.70 ± 3.61. Working with trauma patients, unrealistic expectations of the patient or their relatives, and driving in critical conditions and resuscitation of patients inflicted the highest burden of stress upon the staff. In this study, the mean score of stressor intensity was higher than the mean score of exposure to stressors and a significant correlation was seen between the rate of stress burden with number of operations, educational degree, emergency bases, and status of employment. Conclusion: Proper identification of stressors in terms of prevalence and intensity, leads to better understanding of these factors in pre-hospital emergency and can be of great help in prevention and control of stress burden among emergency medical service staff. مقدمه: پرسنل اورژانس پیش بیمارستانی روزانه در خط مقدم پاسخ اورژانس استرس های فراوانی را تجربه می کنند. شرایط بحرانی و تلاش برای نجات بیماران،عملیات را بر تکنسین های فوریت پزشکی دشوار می نماید. بار استرس در این گروه شغلی مرتبط با حوادث بحرانی، مشکلات عملکردی و عاطفی است که حاصل میزان مواجهه در شدت تنش زا بودن عامل استرس زا است. بنابراین این مطالعه با هدف بررسی بار استرس مرتبط با عملیات اورژانس در بین تکنسین های فوریت پزشکی ایران انجام گرفت. روش کار: در این مطالعه توصیفی- همبستگی 320 تکنسین شاغل در پایگاه های اورژانس پیش بیمارستانی شرکت نمودند. برای جمع آوری داده ها از پرسشنامه ی بررسی بار استرس که حاصل میزان شدت در میزان مواجهه عوامل استرس زا بود استفاده شد. داده ها با استفاده از نرم افزار آماری SPSS و آمار توصیفی و استنباطی مورد تجزیه و تحلیل قرار گرفت. يافته ها: در این مطالعه مهمترین عامل بار استرس عوامل محیطی شغلی و عوامل مربوط به بیمار گزارش شدند. میانگین و انحراف معیار بار استرس 61/3±70/8 بود. کار با بیماران ترومایی، توقعات بیش از حد بیمار و همرا هان آن و رانندگی در شرایط بحرانی و احیاء بیماران، بیشترین بار استرس را بر پرسنل داشتند. در این مطالعه نمره میانگین شدت عوامل استرس زا بالاتر از نمره میانگین میزان مواجهه با عوامل استرس زا بود و بین میزان  بار استرس با تعداد ماموریت، مدرک تحصیلی، پایگاه های اورژانس و وضعیت استخدام ارتباط معنی داری دیده شد. نتيجه گيری: شناسایی خوب عوامل استرس زا از نظر شیوع و شدت، باعث گسترش آگاهی و فهم بهتر از این عوامل در اورژانس پیش بیمارستانی خواهد بود و کمک شایانی در پیشگیری و کنترل بار استرس در پرسنل اورژانس پیش بیمارستانی خواهد کر

Perfluorocarbon liquid-assisted intraocular foreign body removal

We describe the benefits of perfluoro-N-octane (PFO), a perfluorocarbon liquid, in the removal of nonmagnetic intraocular foreign bodies (IOFBs) from the macula and posterior segment. Two consecutive cases of posterior segment IOFB were reviewed. An 18-year-old male presented to the emergency room after a motor vehicle accident with a zone 1 open globe injury and large glass IOFB in the left eye. A 53-year-old male presented to the emergency room with a history of a 3-week delayed presentation of a zone 1 open globe injury from a nail to the right eye. He was found to have a metallic IOFB. In both cases, PFO was used to slide the nonmagnetic IOFBs outside of the macula for safer retrieval. PFO was also able to protect the posterior pole from IOFB drops during early attempts at removal. PFO can be a useful surgical adjunct to pars plana vitrectomy in the removal of certain nonmagnetic IOFBs

Chronic Delivery of Low-Level Exogenous Current Preserves Retinal Function in Pigmented P23H Rat

Diffuse electrical currents delivered to the eye were investigated in a rat model of retinitis pigmentosa for potentially therapeutic effects. Low-level currents were passed between electrodes placed on the cornea and in the mouth during 30-minute sessions two times per week from 4-16 weeks of age. Single-flash electroretinograms (ERG) were recorded and analyzed for amplitude and measures of sensitivity, and basic histology was performed. ERG a-wave amplitudes were slightly greater in treated vs. age-matched controls at 16 wks of age, but the combined thicknesses of the outer nuclear layer and outer segment layer were similar at this age. Treated animals exhibited a significant preservation of b-wave amplitudes, and a striking preservation of rod sensitivity, measured as the stimulus strength required to reach half-saturation of the a-wave. Analysis of the leading edge of the a-wave using a delayed Gaussian function revealed a decrease in the parameter reflecting gain of the phototransduction cascade over the 12-week course of treatment, and no significant change in control animals over the same period. These results suggest that while the exogenous currents failed to preserve the number or gross structure of rods, the responsivity of individual photoreceptors was relatively preserved, perhaps via an increase in efficiency of photon capture (R* / photon). This preserved functionality may delay the retraction of bipolar cell dendrites from degenerating photoreceptors