The most difficult at-fault fatal crashes to avoid with current active safety technology

Objective We studied which current fatal at-fault crashes would occur despite the most advanced current active safety devices (up to SAE level 2 of driving automation) and how frequent these crashes would be. Methods We carried out a cross-sectional study of passenger cars that were first registered during the period 1st January 2010 to 31st December 2017 in Finland. To gain the true exposure for these cars, we accessed the national Vehicular and Driver Data Register to obtain the mileage information and the registration count for the study period of 2010-17. Similarly, we accessed the registry of Finnish road accident investigation teams and included all fatal at-fault crashes among the cars in our study for the same period. We used a real world reference technology for each active safety system in our analysis and chose one car brand as an example. This gave us exact system specifications and enabled testing the operation of the systems on the road. We performed field tests to gain further information on the precise operation of the safety systems in different operating conditions. Finally, we gathered all information on the studied active safety systems and analyzed the investigated at-fault fatal crashes case-by-case using our four level method. Results Cars in our study were the primary party in 113 investigated fatal accidents during the years 2010-17. In 87 of the accidents, the leading cause of death was the injuries due to the crash, and these cases were classified as “unavoidable” (n = 58, 67 %), “avoidable” (n = 26, 30 %) or unsolved (n = 3, 3 %). Of the 58 “unavoidable” crashes 21 (36 %) were suicides, 21 (36%) involved active driver input which would have prevented the safety system operation, 15 (17 %) featured circumstances beyond the safety system performance and in one loss-of-control crash the driver had disabled the relevant safety system (electronic stability control). The registration years of the cars in our study (2010-17) totaled 3,772,864 and during this period, the cars travelled 75.9 billion kilometers. The crash incidence of the “unavoidable” at-fault fatal crashes was 0.76-0.80 fatal crashes per billion kilometers and 15-16 fatal crashes per million registration years. Conclusions We calculated a crash incidence for the “unavoidable” crashes which was 20–27% smaller than the observed crash rate of ESC-fitted passenger cars in our previous study. We concluded that suicides, active driver input until the crash, and challenging weather and road conditions are the most difficult factors for current active safety systems. Our analysis did not account for issues such as system usability or driver acceptance and therefore our results should be regarded as something that is currently theoretically achievable. However, the observed incidence is a good reference for automated driving development and the crash rate of automated cars.Peer reviewe

Kuljettajan sairaus kuolonkolarien aiheuttajana

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Selective changes in human corneal sensation associated with herpes simplex virus keratitis

PURPOSE. To determine corneal sensitivity to selective mechanical, chemical, and thermal (heat and cold) stimulation in patients with a history of herpes simplex virus (HSV) keratitis. METHODS. Corneal sensitivity to different modalities of stimulus was determined in both eyes of 16 patients with unilateral HSV keratitis diagnosed 1 to 12 months before the study. On slit lamp examination, 13 HSV-affected eyes showed corneal scarring or opacities, and three had no signs of previous keratitis. Corneal sensitivity was determined with the Belmonte gas esthesiometer. Mechanical, chemical, heat, and cold stimuli were applied on the central cornea. Eyes from 10 healthy subjects served as controls. RESULTS. In all control and contralateral eyes, selective mechanical, chemical, heat, and cold stimulation evoked sensations of subjective intensity proportional to the magnitude of the applied stimulus. In one HSV patient, the affected cornea was unresponsive to all types of stimuli, four lost only corneal sensitivity to mechanical stimulation, and three lost only sensitivity to heat. Mechanical (P Ͻ 0.005) and heat (P Ͻ 0.05) thresholds were raised in HSV eyes, whereas thresholds for CO 2 were not modified. Also, HSV subjects identified poorly the intensity of mechanical, chemical, and heat stimuli, whereas sensitivity to cold stimulation was unaffected. CONCLUSIONS. In eyes that had had HSV keratitis, corneal sensitivity to mechanical forces and heat was significantly impaired, suggesting that axonal damage and/or altered expression of membrane ion channels involved in transduction and membrane excitability affects primarily the mechano-and polymodal nociceptor terminals. Corneal cold-sensitive terminals remain largely unaffected. (Invest Ophthalmol Vis Sci. 2010; 51:4516 -4522) DOI:10.1167/iovs.10-5225 C orneal infection by herpes simplex virus (HSV) is a common condition that usually develops as an acute or chronic corneal inflammation. 1 The disease is most often due to reactivation of a latent infection of trigeminal sensory neurons innervating the cornea and possibly also of corneal epithelial cells by the neurotropic HSV (HSV1, HSV2, or both). 2,3 As a result, the patient develops an epithelial keratitis. This condition is in many cases recurrent, mainly after HSV-1 infection, 2,5-7 HSV infection often affects also the corneal stroma, inducing a herpes stromal keratitis (HSK). Occasionally, HSV reaches the corneal endothelium, causing endothelial cell loss and permanent corneal swelling. Recurrent episodes may eventually lead to corneal scarring, opacities, and irregular astigmatism. Herpes simplex infection is a common cause of corneal sensory loss, 8 although less severe than in keratitis caused by reactivation of varicella-zoster virus. 10 Sensations evoked at the ocular surface result from the activation of several functional classes of primary sensory neurons located in the trigeminal ganglion (TG), the peripheral axons of which innervate the anterior segment of the eye. 11-13 Polymodal nociceptors, the most abundant receptor type in the cornea, respond to noxious or near-noxious mechanical and thermal stimuli, to exogenous irritants, and to inflammatory agents, predominantly mediating burning pain. Mechanonociceptors are activated only by noxious mechanical forces and possibly elicit mainly pricking pain, whereas cold thermoreceptors respond to small temperature reductions of the corneal surface and evoke cooling and perhaps dryness sensations referred to the eye. 14 -16 Unpleasant and painful ocular sensations arising in HSV keratitis patients may be due to an altered neural activity in infected TG corneal sensory neurons. METHODS Patients Sixteen patients (nine women and seven men; age 40.4 Ϯ 3.7 years, range 16 -66) with a history of unilateral HSV keratitis during the year From th

UBIAD1 Mutation Alters a Mitochondrial Prenyltransferase to Cause Schnyder Corneal Dystrophy

Abstract Background: Mutations in a novel gene, UBIAD1, were recently found to cause the autosomal dominant eye disease Schnyder corneal dystrophy (SCD). SCD is characterized by an abnormal deposition of cholesterol and phospholipids in the cornea resulting in progressive corneal opacification and visual loss. We characterized lesions in the UBIAD1 gene in new SCD families and examined protein homology, localization, and structure

UBIAD1 Mutation Alters a Mitochondrial Prenyltransferase to Cause Schnyder Corneal Dystrophy

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Dystrophia Helsinglandica - corneal morphology, topography and sensitivity in a hereditary corneal disease with recurrent erosive episodes

Purpose: The aim of this study was to describe the morphology, corneal topography and sensitivity in individuals with Dystrophia Helsinglandica. This autosomal dominant corneal disease is characterized by recurrent corneal erosive episodes and progressive subepithelial fibrosis not significantly affecting visual acuity. Methods: The corneas of nine affected and nine unaffected individuals were examined using slit-lamp biomicroscopy, in vivo confocal microscopy (IVCM) and videokeratography. Corneal mechanical sensitivity was also measured using a non-contact esthesiometer. Results: Slit-lamp biomicroscopy revealed that the affected individuals represented different stages of corneal changes, from a nearly normal cornea to subepithelial fibrosis of the central cornea. Corneal changes in affected individuals did not significantly decrease the best spectacle-corrected visual acuity. In vivo confocal microscopy detected morphological changes in the epithelium and stroma. Subepithelial opacity formation including altered keratocytes could be found in the anterior stroma in all affected eyes. With the exception of two eyes (one affected and one unaffected), all videokeratographies showed irregular astigmatism. Corneal sensitivity was significantly lower in affected individuals (p = 0.01). Age and corneal sensitivity showed no correlation. Conclusion: The main morphological findings in affected individuals were discrete and progressive subepithelial fibrosis, in the in vivo confocal microscope corresponding to optically dense extracellular matrix and activated keratocytes. Subbasal nerve morphology was changed in the affected family members who also showed a decreased corneal sensitivity. The findings are per se not specific to the disease. The changes probably reflect a healing response to erosive events on the corneal surface influenced by the genotype

Recovery of Corneal Sensitivity to Mechanical and Chemical Stimulation After Laser in situ Keratomileusis

[Purpose]: To evaluate the time course of changes in corneal sensitivity to mechanical and chemical stimuli produced by laser in situ keratomileusis (LASIK) in humans.[Methods]: We performed a cross-sectional study of 17 LASIK-operated eyes (VisX S2, equipped with version 2.50-3.10 software) and 15 control eyes of 17 individuals to evaluate regeneration of corneal sensitivity after LASIK. Gas pulses of variable flow and compositions were applied to the cornea by a non-contact gas esthesiometer. Mechanical stimuli consisted of air puffs at flows from 0 to 200 ml/min. Chemical stimulation was made with gas pulses containing 0% to 80% CO2 in air at subthreshold flow. Mechanical and chemical thresholds and intensity-response curves for the evoked sensations were determined prior to surgery, and 7 to 9 days, 3 to 5 months, and 1.5 to 2.5 years after surgery.[Results]: Corneal sensitivity to mechanical stimulation was enhanced 7 to 9 days after surgery but subsequently dropped markedly and remained significantly below control levels 3 to 5 months after LASIK. Sensitivity to both mechanical and chemical types of stimuli was close to normal 2 years postoperatively.[Conclusions]: Corneal sensitivity decreased immediately after LASIK but mechanical sensitivity showed a transient hyperesthesia 7 to 9 days afterward. Subsequently, a long-lasting and deep hypoesthesia to mechanical and chemical stimuli was observed. Gas esthesiometry revealed that disturbances of corneal sensation still exist at times when coarse mechanical sensitivity appeared to be normal.Peer reviewe

Corneal sensitivity in diabetic patients subjected to retinal laser photocoagulation.

To determine the changes in corneal sensitivity to different stimulus modalities in diabetes mellitus (DM)1 and DM2 patients with retinopathy, and to explore whether argon laser photocoagulation exacerbates sensitivity loss in diabetic patients. Corneal sensitivity to different modalities of stimulus was determined in one randomized eye in 52 patients with DM1 (n = 35) or DM2 (n = 17), and in 27 healthy subjects. Medical history was obtained from all the patients, including age, sex, time from DM diagnosis, type of diabetes, time from onset of retinopathy, type of diabetic retinopathy, and type of argon laser treatment. Corneal sensitivity was determined using a gas esthesiometer. Mechanical, chemical, and thermal (heat and cold) stimuli were applied on the central cornea. Sensitivity thresholds to selective mechanical, chemical, and cold stimulation were significantly higher in DM patients compared to controls. Sensitivity threshold to mechanical and chemical stimuli was higher in DM2 than in DM1 patients. In DM1 patients, mechanical threshold increased with time after DM diagnosis. No correlation was found between sensitivity thresholds to chemical or thermal stimulation and the age of the patient, type of retinopathy, or time from its diagnosis. Laser treatment generated a further impairment of corneal sensitivity. Corneal sensitivity to mechanical, chemical, and thermal stimulation is decreased in DM patients, suggesting that diabetes affects homogeneously the different types of sensory neurons innervating the cornea. Corneal sensitivity appears to be more disturbed in DM2 than in DM1. Laser treatment of DM patients generates a further impairment in corneal sensitivity, probably as the result of physical damage to ciliary nerves.Supported by Grants SAF2008-00529, BFU2008-04425 and CONSOLIDER CSD2007-00023 from the Ministerio de Ciencia e Innovación, Spain, and Fundación Marcelino Botín, Spain; Helsinki University Research Fund TYH 3316 and 6243; Evald and Hilda Nissi Foundation; Mary och Georg C. Ehrnrooths Foundation; Research Foundation of Orion Corporation; Friends of the Blind Foundation; Leo, Mary and Mary-Ann Hackman Foundation; and the Finnish Eye Foundation.Peer Reviewe

Ka-band 3-stack power amplifier with 18.8 dBm Psat and 23.4 % PAE using 22nm CMOS FDSOI technology

Abstract This paper presents a fully integrated, three-stack power amplifier for 5G wireless systems, designed and fabricated using 22nm CMOS FDSOI technology. The frequency of operation is from 25 GHz to 30.5 GHz, with a maximum 3 dB bandwidth of 5.5 GHz and a maximum gain of 9.9 dB. Maximum RF output power, power-added efficiency (PAE) and output 1 dB compression point are 18.8 dBm, 23.4% and 14.9dBm, respectively, achieved at 28.5 GHz

Analyzing the effects of PA variations on the performance of phased array digital predistortion

Abstract This paper shows how digital predistortion of a phased array can benefit from the parametric variations over parallel power amplifiers (PAs). Different antenna configurations are simulated by varying the PA input drive levels by the Monte-Carlo method. The error vector magnitude (EVM) at the steering angle and total radiated adjacent channel power ratio (TRACPR) are used as performance metrics. The simulation results indicate that array predistortion can benefit from the variations between the PAs to improve the EVM significantly. However, at the same time, the TRACPR performance is reduced. This gives a new trade-off to balance between in-band and out-off-band distortion in the fifth generation beamforming systems