Compositional Set Invariance in Network Systems with Assume-Guarantee Contracts

This paper presents an assume-guarantee reasoning approach to the computation of robust invariant sets for network systems. Parameterized signal temporal logic (pSTL) is used to formally describe the behaviors of the subsystems, which we use as the template for the contract. We show that set invariance can be proved with a valid assume-guarantee contract by reasoning about individual subsystems. If a valid assume-guarantee contract with monotonic pSTL template is known, it can be further refined by value iteration. When such a contract is not known, an epigraph method is proposed to solve for a contract that is valid, ---an approach that has linear complexity for a sparse network. A microgrid example is used to demonstrate the proposed method. The simulation result shows that together with control barrier functions, the states of all the subsystems can be bounded inside the individual robust invariant sets.Comment: Submitted to 2019 American Control Conferenc

Compositional Set Invariance in Network Systems with Assume-Guarantee Contracts

This paper presents an assume-guarantee reasoning approach to the computation of robust invariant sets for network systems. Parameterized signal temporal logic (pSTL) is used to formally describe the behaviors of the subsystems, which we use as the template for the contract. We show that set invariance can be proved with a valid assume-guarantee contract by reasoning about individual subsystems. If a valid assume-guarantee contract with monotonic pSTL template is known, it can be further refined by value iteration. When such a contract is not known, an epigraph method is proposed to solve for a contract that is valid, -an approach that has linear complexity for a sparse network. A microgrid example is used to demonstrate the proposed method. The simulation result shows that together with control barrier functions, the states of all the subsystems can be bounded inside the individual robust invariant sets

Diagnosis and Management of a Patient who Complained of Pain to Cold Following a Recent Visit to a Dental Practice: A Clinical Scenario

The scenario in this paper discusses the diagnosis and management of a patient who complained of pain to cold following a recent visit to a dental practice. The symptoms were localised to one-two teeth in the lower jaw (mandible). On examination, the teeth in question exhibited gingival recession on the buccal (facial) aspects with no obvious signs of dental caries. The gingival tissues were healthy with no periodontal pocketing and the teeth in question were not mobile. Following the application of cold air from a dental triple syringe on to the exposed dentine surface, the patient indicated that they had experienced some discomfort which was sharp but eased somewhat once the air blast was removed. When asked to rate the level of discomfort, the patient indicated that it scored 5 on a visual analogue scale (VAS). The question that will be addressed in this paper is what steps the clinician should take in successfully diagnosis the problem and resolving the patient’s complaint

Quality of life and other psychological factors in patients with tooth wear

Aim: To investigate the relationship between generic and condition-specific (CS) quality of life, general psychological wellbeing and personality in patients with tooth wear. / Materials and methods: Ethical approval was granted (REC:10/H0709/21). Patients aged 18-70 years with tooth wear completed the Oral Impact on Daily Performance (OIDP) quality of life questionnaire, the NEO-FFI Personality questionnaire and the General Health Questionnaire-12 (GHQ). Tooth wear was measured with the Basic Erosive Wear Examination (BEWE). / Results: In total, 102 subjects were recruited. Increased BEWE scores were correlated with older age and worse generic and CS-related quality of life. Increased neuroticism was correlated with increased: generic and CS OIDP scores; generic and CS eating scores; CS smiling scores; and CS carrying out major work scores. Increased GHQ scores were positively correlated with increased: generic and CS OIDP scores; generic and CS eating scores; CS speaking scores; generic and CS cleaning scores; generic relaxing scores; generic and CS smiling scores; and generic emotional state scores (p <0.05). Multivariable linear regression analyses showed that increased neuroticism and decreased GHQ both had an independent effect on generic and CS OIDP scores when adjusted for tooth wear severity (p <0.05). / Conclusion: Quality of life perception is complex and was not only affected by worsening levels of tooth wear

Safety-Critical Control Synthesis for network systems with Control Barrier Functions and Assume-Guarantee Contracts

This paper presents a contract based framework for safety-critical control synthesis for network systems. To handle the large state dimension of such systems, an assume-guarantee contract is used to break the large synthesis problem into smaller subproblems. Parameterized signal temporal logic (pSTL) is used to formally describe the behaviors of the subsystems, which we use as the template for the contract. We show that robust control invariant sets (RCIs) for the subsystems can be composed to form a robust control invariant set for the whole network system under a valid assume-guarantee contract. An epigraph algorithm is proposed to solve for a contract that is valid, ---an approach that has linear complexity for a sparse network, which leads to a robust control invariant set for the whole network. Implemented with control barrier function (CBF), the state of each subsystem is guaranteed to stay within the safe set. Furthermore, we propose a contingency tube Model Predictive Control (MPC) approach based on the robust control invariant set, which is capable of handling severe contingencies, including topology changes of the network. A power grid example is used to demonstrate the proposed method. The simulation result includes both set point control and contingency recovery, and the safety constraint is always satisfied

Histological effects of fibrin glue and synthetic tissue glues on the spinal cord: are they safe to use?

INTRODUCTION: Fibrin glues such as Tisseel(®) have been established in neurosurgery for over thirty years. They are recommended for extradural use but have intradural applications. Brachial plexus reimplantation after trauma requires intradural fibrin glue because reimplanted nerves cannot be sutured to the spinal cord. Recently synthetic glues have become popular in spinal surgery but there is limited information about their safety. Our study compared the histological effects of Tisseel(®), Adherus(®) and BioGlue(®) on spinal cord using our rat brachial plexus repair model. MATERIALS & METHODS: Randomised observational animal study. Forty-one Sprague-Dawley rats divided in to control (n = 9), Tisseel(®) (n = 8), BioGlue(®) (n = 10) and Adherus(®) (n = 14) groups. Under general anaesthesia a posterior midline cervical incision was made and hemi-laminectomies performed at C7 and T1. Dura was opened and T1 dorsal root transected and repositioned on the spinal cord. Two drops of Tisseel(®), BioGlue(®), Adherus(®) or no glue (control) were applied over the cut nerve and cord. At days 7, 14 and 28 rats were euthanized, processed and sections stained with Haematoxylin & Eosin and evaluated blind by a neuropathologist. RESULTS: Control and Tisseel(®) groups showed only mild focal inflammation in the cord. Adherus(®) and Bioglue(®) groups showed evidence of spinal cord inflammation and degeneration. All BioGlue(®) and Adherus(®) rats had evidence of distortion of the cord from the glue mass at all time points. Two BioGlue(®)-treated and one Adherus(®)-treated rat developed a hemiparesis. One BioGlue(®) rat developed hind limb paralysis. One BioGlue(®) rat failed to wake up at the end of the procedure. There were no complications in control and Tisseel(®) groups. CONCLUSION: Tisseel(®) caused a similar inflammatory response to control and may be used on spinal cord. BioGlue(®) and Adherus(®) should be applied thinly for a watertight dural closure but intradural use and contact with spinal tissue must be avoided

Lipoxin receptor agonist and inhibition of LTA4 hydrolase prevent tight junction disruption caused by P. aeruginosa filtrate in airway epithelial cells

Airway diseases can disrupt tight junction proteins, compromising the epithelial barrier and making it more permeable to pathogens. In people with pulmonary disease who are prone to infection with Pseudomonas aeruginosa, pro-inflammatory leukotrienes are increased and anti-inflammatory lipoxins are decreased. Upregulation of lipoxins is effective in counteracting inflammation and infection. However, whether combining a lipoxin receptor agonist with a specific leukotriene A4 hydrolase (LTA4H) inhibitor could enhance these protective effects has not to our knowledge been investigated. Therefore, we explored the effect of lipoxin receptor agonist BML-111 and JNJ26993135 a specific LTA4H inhibitor that prevents the production of pro-inflammatory LTB4 on tight junction proteins disrupted by P. aeruginosa filtrate (PAF) in human airway epithelial cell lines H441 and 16HBE-14o. Pre-treatment with BML-111 prevented an increase in epithelial permeability induced by PAF and conserved ZO-1 and claudin-1 at the cell junctions. JNJ26993135 similarly prevented the increased permeability induced by PAF, restored ZO-1 and E-cadherin and reduced IL-8 but not IL-6. Cells pre-treated with BML-111 plus JNJ26993135 restored TEER and permeability, ZO-1 and claudin-1 to the cell junctions. Taken together, these data indicate that the combination of a lipoxin receptor agonist with a LTA4H inhibitor could provide a more potent therapy

Diabetes UK evidence-based nutrition guidelines for the prevention and management of diabetes

A summary of the latest evidence‐based nutrition guidelines for the prevention and management of diabetes is presented. These guidelines are based on existing recommendations last published in 2011, and were formulated by an expert panel of specialist dietitians after a literature review of recent evidence. Recommendations have been made in terms of foods rather than nutrients wherever possible. Guidelines for education and care delivery, prevention of Type 2 diabetes, glycaemic control for Type 1 and Type 2 diabetes, cardiovascular disease risk management, management of diabetes‐related complications, other considerations including comorbidities, nutrition support, pregnancy and lactation, eating disorders, micronutrients, food supplements, functional foods, commercial diabetic foods and nutritive and non‐nutritive sweeteners are included. The sections on pregnancy and prevention of Type 2 diabetes have been enlarged and the weight management section modified to include considerations of remission of Type 2 diabetes. A section evaluating detailed considerations in ethnic minorities has been included as a new topic. The guidelines were graded using adapted ‘GRADE’ methodology and, where strong evidence was lacking, grading was not allocated. These 2018 guidelines emphasize a flexible, individualized approach to diabetes management and weight loss and highlight the emerging evidence for remission of Type 2 diabetes. The full guideline document is available at www.diabetes.org.uk/nutrition-guidelines

Real-world post-deployment performance of a novel machine learning-based digital health technology for skin lesion assessment and suggestions for post-market surveillance

This is the final version. Available on open access from Frontiers Media via the DOI in this recordData availability statement: The datasets presented in this article are not readily available because the data included in this manuscript have been collected as part of the routine post-market surveillance programme for DERM, conducted by Skin Analytics, London. Requests to access the datasets should be directed to DK, [email protected] and DM, [email protected]: Deep Ensemble for Recognition of Malignancy (DERM) is an artificial intelligence as a medical device (AIaMD) tool for skin lesion assessment. METHODS: We report prospective real-world performance from its deployment within skin cancer pathways at two National Health Service hospitals (UK) between July 2021 and October 2022. RESULTS: A total of 14,500 cases were seen, including patients 18-100 years old with Fitzpatrick skin types I-VI represented. Based on 8,571 lesions assessed by DERM with confirmed outcomes, versions A and B demonstrated very high sensitivity for detecting melanoma (95.0-100.0%) or malignancy (96.0-100.0%). Benign lesion specificity was 40.7-49.4% (DERM-vA) and 70.1-73.4% (DERM-vB). DERM identified 15.0-31.0% of cases as eligible for discharge. DISCUSSION: We show DERM performance in-line with sensitivity targets and pre-marketing authorisation research, and it reduced the caseload for hospital specialists in two pathways. Based on our experience we offer suggestions on key elements of post-market surveillance for AIaMDs