611 research outputs found

    Electromechanical Magnetization Switching

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    We show that the magnetic moment of a composite multiferroic torsional oscillator can be switched by the electric field. The 180o^o switching arises from the spin-rotation coupling and is not prohibited by the different symmetry of the magnetic moment and the electric field as in the case of a stationary magnet. Analytical equations describing the system have been derived and investigated numerically. Phase diagrams showing the range of parameters required for the switching have been obtained.Comment: 7 pages, 5 figure

    A machine learning approach towards detecting dementia based on its modifiable risk factors

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    Dementia is considered one of the greatest global health and social care challenges in the 21st century. Fortunately, dementia can be delayed or possibly prevented by changes in lifestyle as dictated through known modifiable risk factors. These risk factors include low education, hypertension, obesity, hearing loss, depression, diabetes, physical inactivity, smoking, and social isolation. Other risk factors are non- modifiable and include aging and genetics. The main goal of this study is to demonstrate how machine learning methods can help predict dementia based on an individual’s modifiable risk factors profile. We use publicly available datasets for training algorithms to predict participant’ s cognitive state diagnosis, as cognitive normal or mild cognitive impairment or dementia. Several approaches were implemented using data from the Alzheimer’s Disease Neuroimaging Initiative (ADNI) longitudinal study. The best classification results were obtained using both the Lancet and the Libra risk factor lists via longitudinal datasets, which outperformed cross-sectional baseline datasets. Moreover, using only data of the most recent visits provided even better results than using the complete longitudinal set. A binary classification (dementia vs non- dementia) yielded approximately 92% accuracy, while the full multi-class prediction performance yielded to a 77% accuracy using logistic regression, followed by random forest with 92% and 70% respectively. The results demonstrate the utility of machine learning in the prediction of cognitive impairment based on modifiable risk factors and may encourage interventions to reduce the prevalence or severity of the condition in large populations

    Tele-Screening, Triaging of Dental Patients, and Reopening of Dental Services During SAR-CoV2 Pandemic

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    Background: The nature of dental profession requires a dentist to be in a close proximity to the patient’s mouth to perform various operative treatments including procedures such as generating aerosols. As such, dentistry is considered as one of the riskiest profession for the cross-transmission of SARS-CoV2. Although the prevalence and incidence of SARS-CoV2 continue to increase worldwide; the dental services and treatment of non-emergency cases have resumed in many countries including Sudan. Moreover, the use of smartphone technology in communication with patients can play an important role in controlling the spread of SARS-CoV2. Therefore, the aim of this short review was to draw a summary on using smartphone technology for telescreening dental patients prior to their visit to the clinics and to set guidelines and rules for dental treatment during SARS-CoV2 pandemic. Methods:  For the purpose of this study, telescreening is referred as a virtual contact between patients and healthcare personnel used to provide health services during the highly contiguous SARS-CoV2 pandemic. Using a smartphone, dental patients can be screened and questioned about their medical history and particularly for SARS-CoV2 (for symptoms such as fever, headache, coughing, breath shortness, loss of smell or taste). They should also be asked about their travel history to epidemic area, visiting hospital or coming in contact with a confirmed SARS-CoV2 patient during the last 14 days. On arrival to a dental clinic, the patient's temperature should be measured, instruction for wearing masks, hand hygiene, and keeping distances from others inside the waiting zone. Conclusion: Telescreening and triaging will minimize the time of patients’ exposure to dental clinic environments, hence decreasing the risk of getting SARS-CoV2 infection for both patients and dental healthcare workers.  Keywords: COVID-19, dentistry, procedure generating aerosols, smartphone, social distance, surgical masks

    Dynamics of Einstein - de Haas Effect: Application to Magnetic Cantilever

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    Local time-dependent theory of Einstein - de Haas effect is developed. We begin with microscopicinteractions and derive dynamical equations that couple elastic deformations with internal twists due to spins. The theory is applied to the description of the motion of a magnetic cantilever caused by the oscillation of the domain wall. Theoretical results are compared with a recent experiment on Einstein - de Haas effect in a microcantilever.Comment: 7 PR pages, 5 figures, submitted to PR

    A Unique Case of Autoimmune Retinopathy Associated with Anti-Alpha-Enolase Antibodies

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    Background. We report a case of autoimmune retinopathy associated with anti-alpha-enolase antibodies with unique manifestations. Methods. A case report. Results. A 30-year-old male experienced recurrent, primarily peripheral visual field disturbances and minimal photopsia, with interval symptom resolution. Fundus changes subsequently developed in areas corresponding to the previous visual field symptoms. Electroretinogram showed bilaterally symmetric abnormalities of light-adapted responses and suggested loss of photoreceptor function. Only anti-alpha-enolase antibodies were detected on Western blot. Our patient noted cutaneous symptoms at the time of both episodes of visual symptoms, but not in the interim. Biomicroscopy revealed subtle small reddish spots in areas of the peripheral retina corresponding to the areas of the patient's visual field where he noted symptoms. To our knowledge these reddish spots have not been reported in autoimmune retinopathy and may clinically support in vitro and in vivo evidence that anti-alpha-enolase antibodies may target photoreceptors. Conclusions. Our patient demonstrates some unique features adding to the known characteristics of autoimmune retinopathy associated with anti-alpha-enolase antibodies. As more cases are reported, further understanding of the features and pathophysiology of this rare condition will hopefully be elucidated

    Health Beliefs Related to Diabetes Mellitus Prevention among Adolescents in Saudi Arabia

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     Objectives: The incidence of type 2 diabetes mellitus (T2DM) is growing rapidly in the Saudi population. The purpose of this study was to assess the constructs of the health belief model (HBM) as they relate to T2DM lifestyle and prevention behaviours among adolescents. Methods: A cross-sectional study was conducted between May and October 2013 among 426 non-diabetic secondary school students from randomly selected schools in Riyadh, Saudi Arabia. An Arabic version of an adapted English language questionnaire was used to assess knowledge and attitudes related to the severity and prevention of T2DM. A preventative behaviour assessment was also conducted to assess physical activity and dietary habits. Results: The majority of the students (63.4%) had at least one diabetic family member. Obesity was more frequent in males compared to females (P = 0.013). Awareness about the importance of maintaining a healthy body weight to prevent T2DM was lower in males than females (P = 0.037), although males engaged in routine exercise more often (P = 0.001). Males were less likely than females to recognise the risks for T2DM, including obesity (P = 0.030), heredity (P = 0.013) and high fat intake (P = 0.001). Conclusion: An alarmingly high number of Saudi students were unaware of T2DM severity and associated risk factors. Female students were more aware of the benefits of T2DM preventative lifestyle behaviours than males, although males engaged in routine exercise more often. Raising adolescents’ awareness about the primary prevention strategies for T2DM should be a public health priority in Saudi Arabia. The HBM could inform further research on diabetes prevention among Saudi adolescents

    Isolation of Jatropha Curcas Seeds Isolectins with Variable Affinity for Human and Animal Blood Types

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    Background: Lectins are carbohydrate-binding protein which agglutinate glycoconjugates in a reversible way, they are with wide applications in biological and medical sciences. Jatropha curcas belongs to the family euphorbiaceae and is distributed in many tropical and subtropical countries. The toxicity of this plant is known for long ago and has been attributed to several components among which is a protein called curcin. Methods: Jatropha curcas seeds were pulverized and protein was extracted with suitable buffer. Protein extract thus obtained had undergone successive protein precipitations by salting-out using (NH4)2SO4 (AS) at 40, 60, and 80% saturations. Lectin activity was detected by hemagglutination method using human- and animal blood types. AS-precipitated protein fractions that possess lectin activity were tested for their antimicrobial activity against the pathogenic Staphylococcus aureus, Escherichia coli, Bacillus aueras, and Candida albicans. Results: At least three isolectins (Lec40, Lec60, and Lec80) were detected by hemagglutination (HA) and isolated by AS fractionation from the crude Jatropha curcas seed extract (CExt). The isolectins exhibited different tendency toward human and animal blood types. None of the isolectins could inhibit any of the used bacterial strains and Candida albicans. Conclusions: In this study, though the detected lectins resemble their counterpart legume lectins, they, however, showed apparently unique and variable behavior toward human and animal blood types. Which might emphasize on the need for further structural analysis on the affinity sites of these proteins. Keywords: Jatropha curcas; euphorbiaceae; lectin; hemagglutination; antimicrobial activit

    Spatial Determination of Magnetic Avalanche Ignition Points

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    Using time-resolved measurements of local magnetization in the molecular magnet Mn12-ac, we report studies of the propagation of magnetic avalanches (fast magnetization reversals) that originate from points inside the crystals rather than at the edges. The curved nature of the fronts produced by avalanches is reflected in the time-of-arrival at micro-Hall sensors placed at the surface of the sample. Assuming that the avalanche interface is a spherical bubble that grows with a radius proportional to time, we are able to locate the approximate ignition point of each avalanche in a two-dimensional cross-section of the crystal. For the samples used in these studies, avalanches in a given crystal are found to originate in a small region with a radius of roughly 150 microns.Comment: 3 pages, 4 figure
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