Optimal response in siso ripple-free deadbeat systems

The ripple-free deadbeat control problem for SISO plants subjected to arbitrary reference signals is considered. The trade-off between the settling time and the integral square error between the system output and reference signal is investigated. Given a specific order of the controller, it is shown how to design an optimal ripple-free deadbeat controller. An illustrative example is presented to show the feasibility of the proposed algorithm.     

Drug induced oral erythema multiforme: Case report

Introduction:Drug induced oral erythema multiforme a rare clinical entity which involves only the lips and oral mucosa without skin involvement. These lesions are difficult in diagnosing with other oral ulcerative lesions with similar clinical manifestations.Patient concerns:This article presents 2 case reports of Oral erythema multiforme in which drugs were the precipitating factor. Its etiopathogenesis, differential diagnosis and treatment modalities of the disease is discussed.Diagnosis:Based on patient''s complaints, drug history and clinical appearance, provisional diagnosis of drug induced erythema multiforme was considered.Intervention:For case 1, patient was instructed to discontinue usage of drug and prescribed systemic steroid (Prednisolone 10 mg/d) for a week along with germicidal drugs to prevent secondary infection. Medication was tapered to 5 mg/d after first week.For case 2, patient was instructed to discontinue the drug and systemic steroid prednisolone 20 mg /d for 1 week with tapering dose of 10 mg/d for the second week was administered.Outcome:For case 1 and case 2 healing of the lesions were evident on third week of follow up.Conclusion:Medications should be taken under medical supervision. Over the counter drugs might lead to allergic reactions like drug induced oral erythema multiforme, which is a rare variant and needs to be differentiate from other oral ulcerative lesion for prompt management and follow-up.     

Assessment of knowledge of celiac disease among health care professionals

Objectives:

To assess knowledge of celiac disease among medical professionals (physicians).

Methods:

We conducted a cross-sectional survey of hospital-based medical staff in primary, secondary, and tertiary care public, and private hospitals in Riyadh, Saudi Arabia (KSA). We carried out the study between January 2013 and January 2104 at King Khalid University Hospital, King Saud University, Riyadh, KSA. A pretested questionnaire was distributed to the potential participants. A scoring system was used to classify the level of knowledge of participants into 3 categories: poor, fair, and good.

Results:

A total of 109 physicians completed the survey and of these participants, 86.3% were from public hospitals, and 13.7% from private hospitals; 58.7% were males. Of the physicians, 19.2% had poor knowledge. Interns and residents had fair to good knowledge, but registrars, specialists, and even the consultants were less knowledgeable of celiac disease.

Conclusion:

Knowledge of celiac disease is poor among a significant number of physicians including consultants, which can potentially lead to delays in diagnosis. Educational programs need to be developed to improve awareness of celiac disease in the health care profession.Celiac disease (CD) is an autoimmune disorder that is triggered by ingestion of gluten in genetically susceptible individuals. This leads to small intestinal villous atrophy and its ensuing complications. Celiac disease is a common disorder, and the prevalence seems to be on the rise. The exact prevalence of CD in the Middle East and Saudi Arabia (KSA) is not known, but it affects approximately 0.5-1% of the general population in the West.1 The classical presentation of CD is in early childhood with a mal-absorptive picture leading to diarrhea and failure to thrive. However, many cases now present in adulthood. It can also have a variety of non-intestinal presentations such as anemia, fatigue, bone disease, liver enzyme elevation, and infertility.1,2 Highly sensitive screening tests such as immunoglobulin (Ig)A-tissue transglutaminase antibody are now available to screen for CD. The diagnosis of CD is confirmed with small intestinal biopsies, and treatment consists of a strict gluten-free diet for life.3 Health care professionals need to be aware of both the classical and non-classical (extra-intestinal) manifestations of CD in order to make a timely diagnosis. Delays in diagnosis can lead to potentially serious complications such as osteoporosis and small intestinal lymphoma.4 The purpose of the study was to assess the knowledge of CD among the medical professionals. The information obtained will help to design and conduct educational and training programs on CD.     

The prevalance of respiratory viruses among healthcare workers serving pilgrims in Makkah during the 2009 influenza A (H1N1) pandemic

Despite the high risk of acquiring respiratory infections, healthcare workers who treat pilgrims at Hajj have not been studied in previous research on respiratory diseases during Hajj. The objective of this study was to determine the prevalence of different respiratory viruses among healthcare workers who treated pilgrims during Hajj 2009, the year of the influenza A H1N1 pandemic. A cross-sectional study was performed just before and after Hajj (25-29 November, 2009). Nasal and throat swabs were tested for 18 respiratory virus types and subtypes. A total of 184 healthcare workers were examined. Most were men (85%) with an average age of 41 years. Before the Hajj, rates of seasonal influenza vaccination were higher (51%) than rates of pandemic influenza A H1N1 vaccination (22%). After the Hajj, participants reported high rates of maintaining hand hygiene (98%), cough etiquette (89%), and wearing a face mask (90%). Among all the viruses tested, only two were detected: rhinovirus was detected in 12.6% and Coronavirus 229E in 0.6%. Rhinovirus was detected in 21% of those who had respiratory symptoms during Hajj. Influenza A (including H1N1), influenza B. respiratory syncytial virus, other coronaviruses, parainfluenza viruses, human metapneumovirus, adenovirus, and human bocavirus were not detected. The finding of high rates of rhinovirus infection corresponds to their frequent occurrence in adults. None of the participants had influenza A H1N1 2009, possibly because it was also infrequent among the 2009 pilgrims.     

The Saudi Critical Care Society extracorporeal life support chapter guidance on utilization of veno-venous extracorporeal membrane oxygenation in adults with acute respiratory distress syndrome and special considerations in the era of coronavirus disease 2019

Extracorporeal membrane oxygenation (ECMO) is considered as a supportive treatment that provides circulatory and ventilatory support and can be thought off as a bridge to organ recovery. Since 2009, it has been applied as a rescue treatment for patients with severe adult respiratory distress syndrome (ARDS) mainly due to viral causes. In December 2019, several patients presented with a constellation of symptoms of viral pneumonia in China. A new strain of the corona virus family, called COVID-19, has been discovered to be the cause of this severe mysterious illness that was named severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2). This new virus continued to spread across the globe leading to the World Health Organization announcing it as a pandemic in the early 2020. By the end of March 2021, the number of COVID-19 cases worldwide exceeded 126 million cases. In Saudi Arabia, the first confirmed case of COVID-19 was reported in the 2nd March 2020. By the end of March 2021, the total number of confirmed COVID-19 cases in Saudi Arabia is just above 360,000. In anticipation of the need of ECMO for the treatment of patients with SARS‑CoV‑2 based on the previous Middle East respiratory syndrome coronavirus pandemic experience, the Saudi Extra-Corporeal Life Support (ECLS) chapter that is under the umbrella of the Saudi Critical Care Society (SCCS) convened a working group of ECMO experts. The mission of this group was to formulate a guidance for the use of ECMO as a last resort for patients with severe ARDS, especially with COVID-19 based on available evidence. The ECLS-SCCS chapter wanted to generate a document that can be used to simple guide, with a focus on safety, to provide ECMO service for patients with severe ARDS with a special focus on SARS‑CoV‑2.     

A phase II trial for the optimisation of treatment position in the radiation therapy of prostate cancer

BACKGROUND: Patient immobilisation and position are important contributors to the reproducibility and accuracy of radiation therapy. In addition the choice of position can alter the external contour of the treated area and has the potential to alter the spatial relationship between internal organs. The published literature demonstrates variation in the use of the prone and supine position for prostate cancer radiation therapy. Previous investigators using different protocols for patient preparation, imaging and target volume definition have demonstrated changes in the calculated therapeutic ratio comparing the two positions. We did not use rigid immobilisation, laxatives, rectal catheters or bladder voiding and assessed if in the prone position would cause a reduction of the dose to the rectum. We performed a prospective comparison of the two positions in 26 patients to determine if the differences in the spatial relation between the rectum and the planning target volume (PTV) would impact on dose-volume histograms to organs at risk (OAR). We also determined if any such improvement might permit dose escalation. MATERIALS AND METHODS: Twenty-six patients with clinically localized prostate cancer consented to participate in this study. All patients underwent a planning CT scan in both the prone and supine treatment positions. The PTV and OAR were drawn on each set of scans by one of the investigators. The PTV included the prostate and seminal vesicles with a 1cm margin except posteriorly where this margin was reduced to 5mm. The outer circumference of the bladder, rectal wall, small bowel (when present) was drawn along with femoral heads. 3D conformal treatment plans were computed using Helax TMS version 6.1B. A 3-field treatment technique was employed with energy of 10/15 MV. The prescribed dose was 70 Gy and the PTV was encompassed by the 95% isodose and the maximum dose was always less than 107%. Cumulative dose-volume histograms were calculated for the PTV, rectum, bladder, femoral heads and small bowel (when present). These non-uniform histograms for both the prone and supine treatment positions were transformed into uniform ones using the effective volume method [Kutcher J, Burman C. Calculation of probability factors for non-uniform normal tissue irradiation: the effective volume method. Med Phys 1987;14:487]. RESULTS: Twenty-one of the 26 (80%) patients had a lower effective volume of rectum irradiated if the prone instead of the supine treatment position was used. The median value of the effective volume in the supine treatment position was 31.74 Gy while the median value in the prone position was 22.48 Gy. The dose escalation was applied to the patients in the prone treatment position until the effective volume for the rectum was the same as that in the supine position. The range of dose escalation possible for these patients was 0.1-7.9 Gy. These patients could potentially have the dose escalated from the prescribed dose of 70 Gy for the supine position without any increase in side effects. For the five patients where no potential benefit was found when changing treatment position, only two patients displayed a significant (>1 Gy) advantage for the supine treatment position. Twenty-one of the 26 patients also showed an advantage for the prone treatment position in relation to bladder dose. CONCLUSION: The use of the prone position reduced the dose to the unprepared rectum and unvoided bladder in the majority of cases. It should be considered particularly in cases where large posterior seminal vesicles cause significant overlap between the planning target volume and the rectum.     

Nyctohemeral changes in bone turnover assessed by serum bone Gla-protein concentration and urinary deoxypyridinoline excretion: effects of growth and ageing.

1. To investigate whether there is a nyctohemeral rhythm in bone turnover, we measured serum bone Gla-protein (osteocalcin, an index of osteoblast activity) concentration every 2h and urinary deoxypyridinoline (a marker of bone collagen resorption) excretion for 8h periods in 10 pubertal girls (aged 10-14 years), 15 premenopausal women (aged 20-49 years) and 17 postmenopausal women (aged 50-75 years). 2. The serum concentration of bone Gla-protein and the urinary excretion of deoxypyridinoline were five times higher in the pubertal girls than in the premenopausal women. The urinary excretion of deoxypyridinoline in the postmenopausal women was twice that in the premenopausal women. 3. There was a nyctohemeral pattern in all age groups with mean night-time increases of 28% (P < 0.001) in the urinary excretion of deoxypyridinoline and of 5% (P < 0.001) in the serum bone Gla-protein concentration. 4. There also were nyctohemeral patterns in the urinary excretion of calcium (P < 0.02), sodium (P < 0.001) and potassium (P < 0.001), with decreases at night. There was a negative correlation between the night-time changes in the urinary excretion of deoxypyridinoline and calcium, especially in adult women (P < 0.01). 5. The serum level of parathyroid hormone increased with age, but this effect was only observed at night (01.00 to 07.00 hours). There was a nyctohemeral rhythm of the serum intact parathyroid hormone level at all ages, with a peak in the afternoon and night. 6. Thus, at night, there is a large increase in bone resorption and a small increase in osteoblastic activity, representing a nyctohemeral rhythm of bone turnover.(ABSTRACT TRUNCATED AT 250 WORDS)