Designing pair of nonlinear components of a block cipher over quaternion integers

In the field of cryptography, block ciphers are widely used to provide confidentiality and integrity of data. One of the key components of a block cipher is its nonlinear substitution function. In this paper, we propose a new design methodology for the nonlinear substitution function of a block cipher, based on the use of Quaternion integers (QI). Quaternions are an extension of complex numbers that allow for more complex arithmetic operations, which can enhance the security of the cipher. We demonstrate the effectiveness of our proposed design by implementing it in a block cipher and conducting extensive security analysis. Quaternion integers give pair of substitution boxes (S-boxes) after fixing parameters but other structures give only one S-box after fixing parameters. Our results show that the proposed design provides superior security compared to existing designs, two making on a promising approach for future cryptographic applications

Evaluation of the causes and cost impact of returned intravenous medications at a tertiary care hospital in Riyadh, Saudi Arabia

Purpose: To evaluate the main reasons for returning intravenous (IV) medications and to determine its cost impact in an in-patient setting in a Saudi tertiary care hospital.Methods: The study was conducted over a one-month period at the central IV room of the in-patient pharmacy unit at King Abdulaziz Medical City (KAMC), Riyadh, Saudi Arabia. All returned IV medications were evaluated in terms of frequency, causes and cost.Results: The total number of IV medications returned was 2,061 items. The most common reasons for returning IV medications were drug discontinuation (933 items, 45.3 %), dispensing of an extra quantity (396 items, 19.2 %), patient deaths (173 items, 8.4 %), dose changes (171 items, 8.3 %) and drugs being held (150 items, 7.3 %). The total cost of all the returned IV medications was US$26,805.80), which accounts for (13.65$13,877.80) which constitute 51.77 % of returned medication cost.Conclusions: The results of this study indicate that IV medication wastage is a serious problem with significant cost impact, with drug discontinuation and dispensing of an extra quantity of medication being the two main reasons for returning IV medications. Effective communication among health care professionals, pharmacist training, and adherence to standard practice guidelines might be the most vital strategies to reduce medication wastage.Keywords: Medication wastage, In-patient, Cost impact, Intravenous medications, Tertiary car

The development and validation of a multivariable model to predict the bleeding risk score for patients with non-valvular atrial fibrillation using direct oral anticoagulants in the Arab population.

Background Frequently used models, such as the HAS-BLED, ATRIA, ORBIT, and GARFIELD-AF evaluate the risk of bleeding when using an anticoagulant, for example warfarin, in patients with non-valvular atrial fibrillation. Limited studies are available reporting a model with a good discriminative ability to predict the bleeding risk score when using direct oral anticoagulants. Methods Patient data were collected from King Abdulaziz Medical City, King Fahad Cardiac Center, and Prince Sultan Cardiac Center in Riyadh, from outpatients, inpatients, or primary care clinics. In total, 1722 patients with a prescription for a new oral anticoagulant, Dabigatran, Rivaroxaban, or Apixaban, were enrolled. A resampling approach for variable selection was used and a five-fold cross-validation to assess the model fit and misclassification probabilities. The analysis used the receiver operating characteristics curve (ROC) and the concordance (c) statistic to assess the validation models’ discriminative power. The final penalized likelihood parameters were used for the development of the risk prediction tool. The accuracy of a classification and the prediction are reported with the sensitivity, specificity, and Brier score. Results Bleeding occurred in 11.15% of cases, of which 23.08% required a blood transfusion and 51.65% had a reduction in haemoglobin of more than 2 gm. The variable selection model identified 15 predictors associated with major bleeding. The discriminative ability of the model was good (c-statistic 0.75, p = 0.035). The Brier score of the model was 0.095. With a fixed cut-off probability value of 0.12 for the logistic regression equation, the sensitivity was 72.7%, and the specificity 66.3%. Conclusion This model demonstrated a good performance in predicting the bleeding risk in Arab patients treated with novel oral anticoagulants. This easy to use bleeding risk score will allow the clinician to quickly classify patients according to their risk category, supporting close monitoring and follow-up for high-risk patients, without laboratory and radiological monitoring

A novel mathematical model for the effects of wall properties on pumping flow of a biofluid in a symmetrical three-dimensional curved duct

Most pumping actions entail a physical volume change of the duct, which is frequently achieved by having a compliant wall or membrane. To the best of our knowledge, the current study is the first report on a mathematical model developed to analyze the peristaltic transport of a Newtonian fluid in a curved duct with rectangular face and compliant walls. Such geometries are most commonly used in clinical and biological equipment, where the walls of the duct need to be flexible. Flexible ducts are more useful than rigid ones because they do not require any extra modifications or accessories. Here, we have used the conditions of lubrication theory to construct an accurate model, and a common perturbation technique was incorporated to handle the Navier-Stokes equations with emphasis on various aspect ratios and curvatures. A system of curvilinear coordinates operating according to the principles of the cylindrical system was employed to represent the mathematical problem. No-slip boundary limitations were considered at the walls along with the extra constraint of compliant walls showing damping force and stiffness. Comprehensive graphical representations were made to illustrate the effects of all emerging factors of the study in both two- and three-dimensional formats. We found that large curvatures and flexure rigidity decreased the fluid velocity uniformly, but the aspect ratio and amplitude parameters could promote fluid velocity. Validation of the results was performed through the generation of a residual error curve. The current readings were taken again with a straight duct to make a comparison with the existing literature

Medication errors associated with direct-acting oral anticoagulants:analysis of data from national pharmacovigilance and local incidents reporting databases

BACKGROUND: For more than a decade, direct oral anticoagulants (DOACs) have been approved in clinical practice for multiple indications such as stroke prevention in non-valvular atrial fibrillation treatment of deep vein thrombosis and pulmonary embolism. This study aimed to explore the nature and contributory factors related to medication errors associated with DOACs in hospital settings. METHODS: Analysis of error reports using data from (a) Saudi Food and Drug Authority pharmacovigilance database and (b) local incidents reporting system from two tertiary care hospitals were included. Errors reported between January 2010 to December 2020 were also included. Statistical analyses were performed using IBM (SPSS) Statistics Version 24.0 software. RESULTS: A total of 199 medication error incidents were included. The mean (range) age of affected patients was 63.5 (19–96) years. The mean reported duration of treatment when incidents happened was 90 days, with a very wide range from one day to 12 months. Prescribing error was the most common error type representing 81.4% of all errors. Apixaban was the most frequent drug associated with error reporting with 134 (67.3%) incidents, followed by rivaroxaban (18.6%) and dabigatran (14.1%). The majority of the patients (n = 188, 94.5%) showed comorbidities in addition to the conditions related to DOACs. Polypharmacy, an indication of treatment and duration of therapy were amongst the important contributory factors associated with errors. CONCLUSIONS: This observational study demonstrates the nature of DOAC related medication errors in clinical practice. Developing risk prevention and reduction strategies using the expertise of clinical pharmacists are imperative in promoting patient safety associated with DOAC use

Perceived impact of patients’ suicide and serious suicidal attempts on their treating psychiatrists and trainees: a national cross-sectional study in Saudi Arabia

Abstract Background Patient suicides are significant events that tremendously affect psychiatrists— personally and professionally. Very few studies have focused on studying the impact of both serious suicidal attempts and completed suicide on psychiatrists and psychiatry trainees. Aim This study assessed the prevalence and impact of patient suicide and serious suicidal attempts on psychiatrists and psychiatry trainees in Saudi Arabia. Methods This national cross-sectional study of psychiatrists and psychiatry trainees was conducted in Saudi Arabia. Participants completed an online self-administered questionnaire to assess emotional and professional impacts and the traumatic impact of patient suicide using the Impact of Event Scale-Revised (IES-R). Results 178 psychiatrists were enrolled in this study. The prevalence rate of patient suicide among participants was 38.8%, and they experienced adverse emotional reactions. Additionally, among those who were not exposed to patient suicide, 12.9% reported exposure to serious suicide attempts, and almost all of them experienced related negative emotions. The most frequently reported emotions were sadness (61.95%), shock (48.91%), and guilt (25%), and these emotions lasted longer in completed patient suicide cases than attempted suicide. Nearly 84% of participants who experienced suicide reported its impact on their profession. The most reported professional impacts were increased focus on suicide cues, attention to legal aspects, and a tendency to hospitalize. Of participants who experienced suicide, 75.4% reported that the overall impact of suicidal events on their professional practice had improved. Of the total number of respondents who experienced either suicide or serious suicidal attempts, 10.9% reported symptoms of PTSD. Conclusions: The study highlighted the emotional and professional burden that psychiatrists and psychiatry trainees experience due to patient’s completed suicides and serious suicidal attempts. Additionally, it emphasized the need for further research to study the benefits of implementing preparatory and training programs to help trainees and psychiatrists in such instances

Motivators and barriers to research participation among medical students in Saudi Arabia.

Little is known about the obstacles medical students face when conducting research in Saudi Arabia. Moreover, the proportion of medical students in research has been unknown in our region compared to other regions. We sought to identify the barriers and motivators that influence undergraduate medical students in pursuing research. This was a cross-sectional study design, utilizing an online survey distributed through social media platforms from the 17th of December 2021 to the 8th of April 2022. The survey was distributed to four universities in Saudi Arabia. Participants' characteristics, details regarding involvement in research, and attitude towards research were collected. Frequency measures were used to characterize the demographics and chi-squared tests to determine associations. A total of 435 students were included in the final analysis. The highest proportion of students that responded were second year, followed by first year medical students. Less than half (47.6%) of medical students were involved in research. A significant correlation was revealed between the involvement in research and higher participants' Grade Point Average (GPA). The top three incentives for pursuing undergraduate research were "admission into residency programs" (44.8%), "interest in research" (28.7%), and "financial return" (10.8%). However, the top three limitations were "lack of time" (29.2%), "lack of mentoring" (16.8%), and "lack of interest in research" (14.7%). System-related barriers and motivators were the main reasons behind the involvement of medical students in research. Our study is a call for action to raise awareness among medical students about the importance of research and to provide solutions to overcome these barriers

Reliability of Agreement between Insulin, Clonidine, and Glucagon Stimulation Tests for the Diagnosis of Growth Hormone Deficiency in Children: A Retrospective Cohort Study

Growth hormone (GH) deficiency (GHD) is a rare disorder. The diagnosis of GHD requires a combination of two provocative GH tests. This study aimed to find agreement between commonly used medications to determine which combined tests have high reliability of agreement. This retrospective cohort included 201 children who underwent GH provocation testing from January 2012 to December 2022. The insulin tolerance test (ITT) with the clonidine stimulation test (CST) or glucagon stimulation test (GST) with the CST were performed. We calculated Cohen’s kappa to determine the agreement between the test medications by considering the post-stimulation peak GH level with a cut-off value of 10 ng/mL as the primary outcome. A total of 151 patients underwent the two provocative tests and were included in the analysis. Of these patients, 119 underwent the ITT and CST and 54 (45.3%) were diagnosed with GHD. However, 32 patients underwent the GST and CST and 18 (56.2%) were diagnosed with GHD. The kappa value for ITT and CST was 0.258 (25.8%), indicating fair agreement between clonidine and insulin (p = 0.005). However, the kappa value for CST and GST was 0.178 (17.8%), representing slight agreement. The correlation coefficient revealed a very strong relationship between ITT and CST. Clonidine has fair agreement and a very strong correlation coefficient with ITT when used to diagnose GHD in children. Among the commonly used pharmacological tests for GH provocation in our unit, the CST was considered the best pharmacological test in terms of safety and reduced parental anxiety

Saudi Consensus Recommendations on the Management of Multiple Sclerosis: Disease-Modifying Therapies and Management of Relapses

For the past 10 years, disease-modifying therapy (DMT) options for multiple sclerosis (MS) have grown remarkably where DMTs have been shown to reduce the risk of MS relapses. MS patients are advised to begin treatment with a DMT shortly after diagnosis to limit the possibility of disease progression over time. While patients with radiologically isolated syndrome do not require pharmacologic treatment, high-risk patients with clinically isolated syndrome are advised to start DMTs. This article provides evidence-based recommendations for DMT use in MS management, helping healthcare practitioners advise patients on treatment decisions. We aim to provide recommendations for the management of acute MS relapses. The recommendations herein were developed following the gathering of a panel of experts after evaluating international guidelines, and the latest evidence was collected through a comprehensive literature review

Saudi Consensus Recommendations on the Management of Multiple Sclerosis: Disease-Modifying Therapies and Management of Relapses

For the past 10 years, disease-modifying therapy (DMT) options for multiple sclerosis (MS) have grown remarkably where DMTs have been shown to reduce the risk of MS relapses. MS patients are advised to begin treatment with a DMT shortly after diagnosis to limit the possibility of disease progression over time. While patients with radiologically isolated syndrome do not require pharmacologic treatment, high-risk patients with clinically isolated syndrome are advised to start DMTs. This article provides evidence-based recommendations for DMT use in MS management, helping healthcare practitioners advise patients on treatment decisions. We aim to provide recommendations for the management of acute MS relapses. The recommendations herein were developed following the gathering of a panel of experts after evaluating international guidelines, and the latest evidence was collected through a comprehensive literature review