Role of structural defects on exchange bias in the epitaxial CoO/Co system

We have studied the influence of non-magnetic defects throughout the antiferromagnet Co_{1-y}O on the exchange bias (EB) in epitaxially grown Co_{1-y}O/Co bilayers. These defects are either substitutional or structural (twin boundaries and surface morphology) which both lead to an increase of the EB-field. We find a dominance of twin boundaries over surface morphology (roughness) in enhancing EB which is consistent with the domain state model for exchange bias. In contrast, the crystal orientation of the Co_{1-y}O layer does not show a significant effect on the EB in this system.Comment: 10 pages, 2 figure

Origin of training effect of exchange bias in Co/CoO due to irreversible thermoremanent magnetization of the magnetically diluted antiferromagnet

The irreversible thermoremanent magnetization of a sole, magnetically diluted epitaxial antiferromagnetic Co$_{1-y}$O(100) layer is determined by the mean of its thermoremanent magnetizations at positive and negative remanence. During hysteresis-loop field cycling, thermoremanent magnetization exhibits successive reductions, consistent with the training effect (TE) of the exchange bias measured for the corresponding Co$_{1-y}$O(100)/Co bilayer. The TE of exchange bias is shown to have its microscopic origin in the TE of the irreversible thermoremanent magnetization of the magnetically diluted AFM

Sensitive Voltammetric Determination of Acetaminophen at Poly(4-vinyl pyridine)/Graphene Composite Modified Electrode

This study demonstrates the use of a selective and sensitive voltammetric sensor for determination of acetaminophen (AC). This was performed by modifying a glassy carbon electrode with composite film of poly(4-vinylpyridine) and graphene sheet (P4VP/GR-GCE). The redox peak currents of AC increased significantly at P4VP/GR-GCE. The result was achieved by the synergistic effect of combined electron mediator property of P4VP along with remarkable physical properties of GR which improved the kinetics of the catalytic oxidation of AC. The P4VP/GR-GCE exhibited excellent sensitivity, good reproducibilityand long-termstability for measuring AC with detection limits of 3.2 nM in the linear range of 0.04-300 µM. The novel developed sensor was not interfered by physiologically common interference, viz. ascorbic acid (AA) and uric acid (UA). The P4VP/GR-GCE was also successfully applied for detection of AC in tablets and urine samples, so it is reasonable to expect its broad use as AC sensor

The Association between Antihypertensive Drugs and Falls in Older Adults in Amirkola, Northern Iran

Background and Objective: Being familiar with the factors that are effective in causing falls plays an important role in reducing the issues and costs related to its treatment. Considering the contradictory results about the use of antihypertensive drugs and falls in older adults, the present study was conducted to determine the association between the use of antihypertensive drugs and falls in older adults. Methods: This cross-sectional study was a part of the first phase of Amirkola Health and Ageing Project (AHAP), which was conducted on three groups of 250 people including healthy elderly, and hypertensive patients with and without taking antihypertensive drugs. Antihypertensive drugs were divided into 6 groups based on the mechanism of action. The variables of age, gender, body mass index, physical activity, diabetes, number of medications, depression symptoms, cognitive status, number of comorbidities, and the frequency of falls during one year before the beginning of the study and during the six-month follow-up were evaluated and compared in different categories of antihypertensive drugs by asking older adults in the three groups. Findings: Out of all studied older adults, 126 people (16.8%) fell during the last 12 months and 36 people (4.8%) fell during the six-month follow-up. No significant relationship was found between falls and the use of antihypertensive drugs, and between the use of different classes of antihypertensive drugs and falls. Variables such as depressive symptoms (OR=2.057, p=0.001), number of comorbidities (OR=0.189, p=0.006) and older age (OR=1.033, p=0.040) had an effective role in causing falls. Conclusion: The results of the study showed that the use of antihypertensive drugs and their different classes was not associated with the increase in the frequency of falls in older adults

Complex ferromagnetic state and magnetocaloric effect in single crystalline Nd_{0.7}Sr_{0.3}MnO_{3}

The magnetocaloric effect in single crystalline Nd_{0.7}Sr_{0.3}MnO_{3} is investigated by measuring the field-induced adiabatic change in temperature which reveals a single negative peak around 130 K well below the Curie temperature (T_C=203 K). In order to understand this unusual magnetocaloric effect, we invoke the reported {55}^Mn spin-echo nuclear magnetic resonance, electron magnetic resonance and polarized Raman scattering measurements on Nd_{0.7}Sr_{0.3}MnO_{3}. We show that this effect is a manifestation of a competition between the double exchange mechanism and correlations arising from coupled spin and lattice degrees of freedom which results in a complex ferromagnetic state. The critical behavior of Nd_{0.7}Sr_{0.3}MnO_{3} near Curie temperature is investigated to study the influence of the coupled degrees of freedom. We find a complicated behavior at low fields in which the order of the transition could not be fixed and a second-order-like behavior at high fields.Comment: Accepted for publication in Phys. Rev.

Prospective evaluation of endoscopic ultrasonography in the diagnosis of biliary microlithiasis in patients with normal transabdominal ultrasonography

Prior investigators have proposed microlithiasis as a causative factor for occult gallbladder diseases. Endoscopic ultrasonography (EUS) is potentially far more sensitive than transabdominal ultrasonography (TUS) in visualizing small stones. The aim of this study was to investigate the role of endoscopic ultrasonography (EUS) in the diagnosis of microlithiasis in patients with upper abdominal pain and normal TUS. Thirty-five patients with biliary-type abdominal pain and normal TUS results were prospectively studied. All patients underwent radial EUS by means of a GF UM-20 echoendoscope (Olympus Optical, Tokyo, Japan). Of 35 patients, 33 were revealed to have gallbladder sludge or small stones, and 21 had CBD sludge or microlithiasis. Nine patients were not available for follow-up; of the remaining patients, 13 underwent combined endoscopic biliary sphincterotomy and cholecystectomy, 10 underwent cholecystectomy, and 3 underwent biliary sphincterotomy alone. In a postoperative follow-up at 9.2 months, 25 patients (96.2) were symptom free. EUS is an important diagnostic tool in patients with unexplained biliary colic. Cholecystectomy with or without EUS is an effective treatment modality in these settings. © 2005 The Society for Surgery of the Alimentary Tract

A Novel Mutation in the OFD1 Gene in a Family with Oral-Facial-Digital Syndrome Type 1: A Case Report.

Oral-facial-digital syndrome as heterogeneous developmental conditions is characterized by abnormalities in the oral cavity, facial features and digits. Furthermore, central nervous system (CNS) abnormalities can also be part of this developmental disorder. At least 13 forms of OFDS based on their pattern of signs and symptoms have been identified so far. Type 1 which is now considered to be a ciliopathy accounts for the majority of cases. It is transmitted in an X-linked dominant pattern and caused by mutations in OFD1 gene, which can result in embryonic male lethality. In this study, we present a family suffering from orofaciodigital syndrome type I who referred to Medical Genetics Research Center, Shahid Sadoughi University of Medical Sciences in 2015. Two female siblings and their mother shared a novel 2-base pair deletion (c.1964-1965delGA) in exon 16 of OFD1 gene. Clinically, the sibling had oral, facial and brain abnormalities, whereas their mother is very mildly affected. She also had history of recurrent miscarriage of male fetus