Development and Validation of Functional Model of a Cruise Control System

Modern automobiles can be considered as a collection of many subsystems working with each other to realize safe transportation of the occupants. Innovative technologies that make transportation easier are increasingly incorporated into the automobile in the form of functionalities. These new functionalities in turn increase the complexity of the system framework present and traceability is lost or becomes very tricky in the process. This hugely impacts the development phase of an automobile, in which, the safety and reliability of the automobile design should be ensured. Hence, there is a need to ensure operational safety of the vehicles while adding new functionalities to the vehicle. To address this issue, functional models of such systems are created and analysed. The main purpose of developing a functional model is to improve the traceability and reusability of a system which reduces development time and cost. Operational safety of the system is ensured by analysing the system with respect to random and systematic failures and including safety mechanism to prevent such failures. This paper discusses the development and validation of a functional model of a conventional cruise control system in a passenger vehicle based on the ISO 26262 Road Vehicles - Functional Safety standard. A methodology for creating functional architectures and an architecture of a cruise control system developed using the methodology are presented.Comment: In Proceedings FESCA 2016, arXiv:1603.0837

Joseph Buford Pennybacker CBE MD FRCS (1907-1983): Continuing Sir Hugh Cairns’ Oxford Legacy and Pioneer of the Modern Management of Cerebral Abscesses

The authors examine the life and contribution of Joseph Buford Pennybacker to British neurosurgery and the modern management of cerebral abscesses. Pennybacker’s inspirational journey began with him aspiring to Ephraim McDowell. It saw him cross the Atlantic, learn medicine at Edinburgh, train in neurology at Queen Square in London and learn neurosurgery under Sir Hugh Cairns in Oxford. He navigated a successful career through World War Two and together with Cairns established the Radcliffe Infirmary in Oxford as a highly esteemed neurosurgical unit. By increasing the operative tempo yet uncompromising the meticulousness of his operative technique, Pennybacker challenged the Halstedian and Cushing traditions. The pioneering Pennybacker system of managing cerebral abscesses stood the test of time and the ethos of pre-operative imaging, intervention and post-operative monitoring - clinically, biochemically and with imaging results remains today. Not only did he contribute significantly to British neurosurgery and the training of both home-grown and international neurosurgeons, he was a remarkably kind-hearted and calm person. These qualities inspired many of his contemporaries and junior colleagues and we hope will continue to do so for generations to come

Multi-Objective Optimization of Single Point Incremental Forming of 316L Stainless Steel Using Grey Relational and Principal Component Analyses

The single point incremental forming process has a wide range of applications, and the process can be carried out without any specialized tooling and punches. However, if the process parameters are not carefully chosen, the components being manufactured are limited. This paper presents the single point incremental forming of 316L stainless steel sheets of 0.8 mm in thickness by varying input process parameters, such as tool diameter, wall angle, step depth, spindle speed, and feed rate, to study their effect on output parameters, strain and surface roughness. The Taguchi method was coupled with principal component analysis to identify the optimum process parameter combination to improve strain and reduce surface roughness. The wall angle has been determined to be the most influential process parameter, and the analysis of variance showed that the wall angle had the highest contribution (52.44 %), followed by step depth (18.55 %), tool diameter (9.72 %), spindle speed (1.64 %), and feed rate (0.83 %). The suggested design of experiments determined the best process parameter combination and executed the confirmation run. The grey relational analysis combined with principal component analysis improved the single point incremental forming of 316L stainless steel sheets

Local exchange-correlation potentials by density inversion in solids

Following Hollins et al. [J. Phys.: Condens. Matter 29, 04LT01 (2017)], we invert the electronic ground-state densities for various semiconducting and insulating solids calculated using several density functional approximations within the generalized Kohn-Sham (GKS) scheme, which includes Hartree-Fock (HF) theory, hybrid schemes, and the LDA+ method. To appraise the role of locality versus nonlocality in the effective KS/GKS potential, the band structures from the resulting local exchange-correlation (LXC) Kohn-Sham potential are then compared with the band structures of the original GKS method. We find the LXC potential obtained from the HF density systematically predicts band gaps in good agreement with experiment, including for strongly correlated transition metal monoxides. Furthermore, we find that the HSE06 and PBE0 hybrid functionals yield similar densities and LXC potentials to each other. In weakly correlated systems, these potentials are also similar to PBE. For LDA+ densities, the LXC potential partly reverses the excessive flattening of bands caused by too-large Hubbard values. For meta-GGAs, we find only small differences between the GKS and LXC results, demonstrating that the nonlocality of meta-GGAs is weak

Spinal cord perfusion pressure correlates with breathing function in patients with acute, cervical traumatic spinal cord injuries: an observational study.

OBJECTIVE: This study aims to determine the relationship between spinal cord perfusion pressure (SCPP) and breathing function in patients with acute cervical traumatic spinal cord injuries. METHODS: We included 8 participants without cervical TSCI plus 13 patients with cervical traumatic spinal cord injuries, American Spinal Injury Association Impairment Scale grades A-C. In the TSCI patients, we monitored intraspinal pressure from the injury site for up to a week and computed the SCPP as mean arterial pressure minus intraspinal pressure. Breathing function was quantified by diaphragmatic electromyography using an EDI (electrical activity of the diaphragm) nasogastric tube as well as by ultrasound of the diaphragm and the intercostal muscles performed when sitting at 20°-30°. RESULTS: We analysed 106 ultrasound examinations (total 1370 images/videos) and 198 EDI recordings in the patients with cervical traumatic spinal cord injuries. During quiet breathing, low SCPP ( 100 mmHg. CONCLUSIONS: After acute, cervical traumatic spinal cord injuries, breathing function depends on the SCPP. SCPP 80-90 mmHg correlates with optimum diaphragmatic and intercostal muscle function. Our findings raise the possibility that intervention to maintain SCPP in this range may accelerate ventilator liberation which may reduce stay in the neuro-intensive care unit

Evolution of Spinal Cord Swelling in Acute Traumatic Spinal Cord Injury

We hypothesized that the Monro–Kellie doctrine, a key principle in traumatic brain injury (TBI), also applies in traumatic spinal cord injury (TSCI). By analyzing 9986 h of intraspinal pressure (ISP) monitoring data from 79 TSCI patients, we show that concepts developed to quantify compensatory reserve in TBI may be analogously defined in TSCI, termed ISP pulse amplitude (sAMP), spinal compensatory reserve index (sRAP), and ISP waveform shape. As ISP increases beyond 15 mmHg, compensatory reserve becomes impaired (sAMP rises and sRAP becomes positive). As ISP increases beyond 20 mmHg, the morphology of the ISP waveform changes from three peaks (P1, P2, P3) with P1 dominant, to three peaks with P2 dominant, to a rounded signal. Key differences in TSCI, compared with TBI, are no plateau ISP waves, and no critical ISP beyond which sAMP decreases and sRAP becomes negative. Four factors were associated with increased spinal cord swelling or reduced spinal cord compliance: thoracic level of injury, no laminectomy, delayed surgery, and more severe injury. We also hypothesized that, as in TBI, the spinal cord maximally swells a few days after injury. Serial ultrasound scans of the injured spinal cords in 9 patients and plots of change from baseline in ISP, sAMP, and sRAP versus time in 79 patients revealed delayed maximal cord swelling within 5 days of surgery. We conclude that the spinal Monro–Kellie concept allows the spinal compensatory reserve to be quantified. Our data show that spinal compensatory reserve becomes exhausted as ISP increases above 15–20 mmHg and that there is delayed cord swelling after injury, which implies that adequate cord decompression confirmed during surgery by ultrasound may not persist postoperatively

Recurrent terminal ventricle cyst: a case report.

The terminal ventricle (TV) of Krause is a rare cystic dilation of the conus' central canal. Due to limited understanding surrounding its pathophysiology, optimal management remains controversial. We report a 25-year-old female presenting with acute paraparesis. Magnetic resonance imaging spine revealed a cystic conus medullaris lesion in keeping with an incidental TV cyst. However, the patient experienced a rapid resolution of symptoms. We hypothesize that the TV cyst spontaneously ruptured and auto-decompressed. To our knowledge, this is the first reported case of an enlarging symptomatic TV cyst with spontaneous rupture and resolution of symptoms, highlighting the variable natural history of this condition

Duroplasty for injured cervical spinal cord with uncontrolled swelling: protocol of the DISCUS randomized controlled trial

Background Cervical traumatic spinal cord injury is a devastating condition. Current management (bony decompression) may be inadequate as after acute severe TSCI, the swollen spinal cord may become compressed against the surrounding tough membrane, the dura. DISCUS will test the hypothesis that, after acute, severe traumatic cervical spinal cord injury, the addition of dural decompression to bony decompression improves muscle strength in the limbs at 6 months, compared with bony decompression alone. Methods This is a prospective, phase III, multicenter, randomized controlled superiority trial. We aim to recruit 222 adults with acute, severe, traumatic cervical spinal cord injury with an American Spinal Injury Association Impairment Scale grade A, B, or C who will be randomized 1:1 to undergo bony decompression alone or bony decompression with duroplasty. Patients and outcome assessors are blinded to study arm. The primary outcome is change in the motor score at 6 months vs. admission; secondary outcomes assess function (grasp, walking, urinary + anal sphincters), quality of life, complications, need for further surgery, and mortality, at 6 months and 12 months from randomization. A subgroup of at least 50 patients (25/arm) also has observational monitoring from the injury site using a pressure probe (intraspinal pressure, spinal cord perfusion pressure) and/or microdialysis catheter (cord metabolism: tissue glucose, lactate, pyruvate, lactate to pyruvate ratio, glutamate, glycerol; cord inflammation: tissue chemokines/cytokines). Patients are recruited from the UK and internationally, with UK recruitment supported by an integrated QuinteT recruitment intervention to optimize recruitment and informed consent processes. Estimated study duration is 72 months (6 months set-up, 48 months recruitment, 12 months to complete follow-up, 6 months data analysis and reporting results). Discussion We anticipate that the addition of duroplasty to standard of care will improve muscle strength; this has benefits for patients and carers, as well as substantial gains for health services and society including economic implications. If the addition of duroplasty to standard treatment is beneficial, it is anticipated that duroplasty will become standard of care. Trial registration IRAS: 292031 (England, Wales, Northern Ireland) - Registration date: 24 May 2021, 296518 (Scotland), ISRCTN: 25573423 (Registration date: 2 June 2021); ClinicalTrials.gov number : NCT04936620 (Registration date: 21 June 2021); NIHR CRN 48627 (Registration date: 24 May 2021)

Removal or retention of minimally invasive screws in thoracolumbar fractures? Systematic review and case-control study.

BACKGROUND: There is uncertainty regarding delayed removal versus retention of minimally invasive screws following percutaneous fixation for thoracolumbar fractures. We conducted a systematic review and case-control study to test the hypothesis that delayed metalwork removal following percutaneous fixation for thoracolumbar fractures improves outcome. METHODS: A systematic review was performed in accordance with the PRISMA guidelines. Our case-control study retrospectively evaluated 55 consecutive patients with thoracolumbar fractures who underwent percutaneous fixation in a single unit: 19 with metalwork retained (controls) and 36 with metalwork removed. Outcomes were the Oswestry Disability Index (ODI), a supplemental questionnaire, and complications. RESULTS: The systematic review evaluated nine articles. Back pain was reduced in most patients after metalwork removal. One study found no difference in the ODI after versus before metalwork removal, whereas three studies reported significant improvement. Six studies noted no significant alterations in radiological markers of stability after metalwork removal. Mean complication rate was 1.7% (0-6.7). Complications were superficial wound infection, screw breakage at the time of removal, pull-out screw, and a broken rod. In the case-control study, both groups were well matched. For metalwork removal, mean operative time was 69.5 min (range 30-120) and length of stay was 1.3 days (0-4). After metalwork removal, 24 (68.6%) patients felt better, 10 (28.6%) the same and one felt worse. Two patients had superficial hematomas, one had a superficial wound infection, and none required re-operation. Metalwork removal was a significant predictor of return to work or baseline household duties (odds ratio 5.0 [1.4-18.9]). The ODI was not different between groups. CONCLUSIONS: The findings of both the systematic review and our case-control study suggest that removal of metalwork following percutaneous fixation of thoracolumbar fractures is safe and is associated with improved outcome in most patients

Spinal myxomas: review of a rare entity.

Intramuscular myxomas are rare, benign mesenchymal tumours, occurring predominantly in large skeletal muscles as large, slow-growing and painless masses. Spinal occurrence is rare, and may present incidentally, or diagnosed via localized symptoms secondary to local infiltration of surrounding structures. Differential diagnosis based on imaging includes sarcomas, meningiomas and lipomas. We discuss two contrasting cases presenting with well-circumscribed cystic paraspinal lesions indicative of an infiltrative tumour and discuss the radiological and histological differences that distinguish myxomas from similar tumours. Surgical resection of the tumour was performed in both cases, however one patient required surgical fixation due to bony erosion secondary to tumour infiltration. Immuno-histopathological analysis confirmed the diagnosis of a cellular myxoma. Follow up imaging at 6 months confirmed no symptomatic or tumour recurrence in both cases. Histological analysis is the definitive means for diagnosis to differentiate myxomas from other tumours. Recurrence is rare if full resection is achieved