Genetic algorithm optimization of heliostat field layout for the design of a central receiver solar thermal power plant.

The heliostat field layout in a central receiver solar thermal power plant has significant optical losses that can ultimately affect the overall output power of the plant. In this paper, an optimized heliostat field layout based on annual efficiency and power of 50 MW for the local coordinates of Quetta, Pakistan, is proposed. The performance of two different heliostat field layouts such as radial staggered and Fermat's spiral distribution are evaluated and different design points in a year are considered for the analysis. The field layouts are then optimized using a rejection sampling based Genetic Algorithm (GA). It considers the output power and mean overall efficiency for vernal equinox, summer solstice, autumnal equinox, and winter solstice as objective functions. The GA optimizes the heliostat field parameters, namely, security distance (DS), tower height (TH), heliostat width to length ratio (WR), and the length of heliostats (LH). The study system was developed in MATLAB for validation. It was observed that for the radial staggered layout, the number of heliostats decreased by 364 and the efficiency was improved by 8.52 % using GA optimization relative to unoptimized results field layout. The annual efficiency for Fermat's spiral configuration was improved by 14.62 % and correspondingly, the number of heliostats decreased by 434.

Thrombotic Microangiopathy Secondary to Disseminated Varicella Zoster Virus Infection in an Adult Patient.

BACKGROUND Thrombotic microangiopathy (TMA) is a life-threatening condition caused by small-vessel platelet microthrombi. While various disease triggering factors, including infections, have been well described, there have been few reports of an association between TMA and varicella zoster virus (VZV) infection. VZV infection is rare among people age 20 and older, and infection-induced TMA is mostly reported in the pediatric age group. We report a case of TMA induced by a disseminated VZV infection in an adult. CASE REPORT A 43-year-old man presented with a 3-day duration of fever, headache, vomiting, and bloody diarrhea. He also reported body rash after a recent contact with a few roommates with chickenpox. On presentation, the patient developed convulsive seizures. His laboratory test results were significant for acute kidney injury (AKI) and thrombocytopenia. Atypical hemolytic uremic syndrome (aHUS) and thrombotic thrombocytopenic purpura (TTP) were suspected but further diagnostic testing was negative. The treatment plan included acyclovir, therapeutic plasma exchange, and high-dose oral prednisolone (1.5 mg/kg). The clinical and biochemical profile significantly improved, and the patient was discharged home. CONCLUSIONS TMA is a life-threatening hematological emergency with a high mortality rate. Compared to the pediatric population, VZV infection tends to be more severe in the adult age group. This case demonstrates that a high index of suspicion for TMA in adult patients with VZV who present with thrombocytopenia, even when there is no definitive diagnosis, can result in early management with favorable outcome.

Multi-Disciplinary Discharge Coordination Team to Overcome Discharge Barriers and Address the Risk of Delayed Discharges.

BACKGROUND: Delays in hospital discharge occur when patients are medically cleared but continue to remain hospitalized. Discharge delays can result in reduced levels of treatment, placing patients at risk of functional decline, falls and hospital-related adverse events. The Institute of Medicine has highlighted timely, efficient, and safe hospital discharge as a marker for quality care. Hospitals, however, are often unable to meet discharge targets. Research has shown improvements in discharge planning through system-level approaches that integrate health care and social work. The purpose of this study is to describe the development and implementation of a multidisciplinary team intervention to overcome discharge barriers for patients with prolonged hospitalization. We also evaluated the impact of the intervention on length of stay, readmission rates and care team satisfaction and morale. METHODS: A multidisciplinary discharge coordination team met weekly to proactively raise and resolve patient-related discharge issues for all patients admitted to the general medicine wards. Members included hospitalists, case managers, social workers, hospital finance representatives, and patient representatives. One of the hospital physicians facilitated the meetings. RESULTS: Barriers to discharge included patient and family reluctance to discharge, medical delays in performing diagnostic tests or procedures, long-term care facility acceptance delays, and prolonged wait times for insurance approvals. Our multipronged approach decreased length of stay in our delayed discharge patient population from 15.45 days to 9.04 days, a 41.5% reduction, without an increase in readmissions. The healthcare team perceived the weekly multidisciplinary team meetings quite positively; 90% of respondents agreed that the meetings improved communication and increased their sense of support. CONCLUSION: Our intervention was successful in improving hospital processes to overcome barriers to patient discharge. We believe that similar multidisciplinary meetings can be implemented in hospitals throughout the region to decrease risks of prolonged hospitalization and, ultimately, improve hospital efficiency and care delivery.

Post-infectious and post-acute sequelae of critically ill adults with COVID-19.

BACKGROUND: Data on the post-acute and post-infectious complications of patients who have recovered from severe coronavirus disease 2019 (COVID-19) are limited. While studies report that approximately 5-15% of COVID-19 hospitalized patients require intensive care and mechanical ventilation, a substantially higher number need non-invasive ventilation and are subject to prolonged hospitalizations, with long periods of immobility and isolation. The purpose of this study is to describe the post-infectious sequelae of severe viral illness and the post-acute complications of intensive care treatments in critically ill patients who have recovered from severe COVID-19 infection. METHODS: We performed a retrospective chart review of adult patients initially hospitalized with confirmed COVID-19 infection, who recovered and were transferred to a general medical ward or discharged home between March 15, 2020 and May 15, 2020, dates inclusive, after an intensive care unit (ICU) or high dependency unit (HDU) admission in a designated COVID-19 hospital in the United Arab Emirates. Demographic data, underlying comorbidities, treatment, complications, and outcomes were collected. Descriptive statistical analyses were performed. RESULTS: Of 71 patients transferred out of ICU (n = 38, 54%) and HDU (n = 33, 46%), mean age was 48 years (SD, 9.95); 96% men; 54% under age 50. Mean ICU stay was 12.4 days (SD, 5.29), HDU stay was 13.4 days (SD, 4.53). Pre-existing conditions were not significantly associated with developing post-acute complications (Odds Ratio [OR] 1.1, 95% confidence interval [CI] 0.41, 2.93, p = 1.00). Fifty nine percent of patients had complications; myopathy, swallowing impairments, and pressure ulcers were most common. Delirium and confusion were diagnosed in 18% (n = 13); all were admitted to the ICU and required mechanical ventilation. Of note, of all patients studied, 59.2% (n = 42/71) had at least 1 complication, 32.4% (n = 23) had at least 2 complications, and 19.7% (n = 14) suffered 3 or more sequelae. Complications were significantly more common in ICU patients (n = 33/38, 87%), compared to HDU patients (n = 9/33, 27%) (OR 17.6, 95% CI 5.23, 59.21, p <0.05). CONCLUSION: In a subset of critically ill patients who recovered from severe COVID-19 infection, there was considerable short-term post-infectious and post-acute disability. Long-term follow-up of COVID-19 survivors is warranted.

New onset adrenal insufficiency in a patient with COVID-19.

SARS-CoV-2 is the cause of COVID-19. Since the outbreak and rapid spread of COVID-19, it has been apparent that the disease is having multi-organ system involvement. Still its effect in the endocrine system is not fully clear and data on cortisol dynamics in patients with COVID-19 are not yet available. SARS-CoV-2 can knock down the host's cortisol stress response. Here we present a case of a 51-year-old man vomiting for 10 days after having confirmed COVID-19 infection. He had hypotension and significant hyponatraemia. Work-up was done including adrenocorticotropic hormone stimulation test. He was diagnosed as suffering from adrenal insufficiency and started on steroids with subsequent improvement in both blood pressure and sodium level. COVID-19 can cause adrenal insufficiency. Clinicians must be vigilant about the possibility of an underlying relative cortisol deficiency in patients with COVID-19.

Prescription errors in the National Health Services, time to change practice.

INTRODUCTION: Medication error is a major source of iatrogenic illness. Error in prescription is the most common form of avoidable medication error. We present our study, performed at two, UK, National Health Services Hospitals. MATERIAL AND METHODS: The prescription practice of junior doctor's working on general medical and surgical wards in National Health Service District General and University Teaching Hospitals in the UK was reviewed. Practice was assessed against standard hospital prescription charts, developed in accordance with local pharmacy guidance. RESULTS: A total of 407 prescription charts were reviewed in both initial audit and re-audit one year later. In the District General Hospital, documentation of allergy, weight and capital-letter prescription was achieved in 31, 5 and 40% of charts, respectively. Forty-nine per cent of discontinued prescriptions were properly deleted and signed for. In re-audit significant improvement was noted in documentation of the patient's name 100%, gender 54%, allergy status 51% and use of generic drug name 71%. Similarly, in the University Teaching Hospital, 82, 63 and 65% compliance was achieved in documentation of age, generic drug name prescription and capital-letter prescription, respectively. Prescription practice was reassessed one year later after recommendations and changes in the prescription practice, leading to significant improvement in documentation of unit number, generic drug name prescription, insulin prescription and documentation of the patient's ward. CONCLUSION: Prescription error remains an important, modifiable form of medical error, which may be rectified by introducing multidisciplinary assessment of practice, nationwide standardised prescription charts and revision of current prescribing clinical training.

Stent dilatation of atretic aortic coarctation in an adult-case report and literature review.

BACKGROUND: Patients with functional aortic interruption of the descending thoracic aorta at the isthmus due to severe coarctation in association with atretic lumen are extremely rare in the adult population. The management is challenging and carries high morbidity and mortality. CASE PRESENTATION: We describe successful percutaneous reconstruction using a covered stent in a similar patient who is doing well two-years after intervention. A literature search was done to explore management strategies and their long-term outcomes for better understanding. CONCLUSIONS: This report is an attempt to highlight the role of minimal invasive approach in the management of rare, severe coarctation of the aorta in adult patients to avoid morbidity and mortality associated with more invasive procedures.