Sloshing Model for ENSO

The El Nino southern oscillation (ENSO) behavior can be effectively modeled as a response to a 2nd-order Mathieu/Hill differential equation with periodic coefficients describing sloshing of a volume of water. The forcing of the equation derives from QBO, angular momentum changes synchronized with the Chandler wobble, and solar insolation variations. One regime change was identified in 1980. (See floating note)Comment: 4 pages, 5 figure

Enzyme activity in terrestrial soil in relation to exploration of the Martian surface

Urease activity in soil is persistent for long periods under low water, low temperature, and sterile regimes, and it was suggested that some form of enzyme-protective mechanism exists in soil. Dublin soil was extracted by sonication in water followed by adding a mixture of salts. Urease activity is associated with the organo-mineral complex thus obtained and is resistant to the activities of proteolytic enzymes. Clay free soil organic matter prepared subsequently by filtration also exhibits urease activity which is resistant to proteolysis. Models consisting of enzymes with bentonite and lignin were found to mimic this resistance to proteolysis. A model system is presented which suggests both the origin and location of soil ureases and a reason for their persistence in nature

Case report : Multiple UGT1A1 gene variants in a patient with Crigler-Najjar syndrome

Publisher Copyright: © 2018 The Author(s).Background: Inherited unconjugated hyperbilirubinemia is caused by variants in the gene UGT1A1 leading to Gilbert's syndrome and Crigler-Najjar syndrome types I and II. These syndromes are differentiated on the basis of UGT1A1 residual enzymatic activity and its affected bilirubin levels and responsiveness to phenobarbital treatment. Case presentation: In this report, we present a boy with Crigler-Najjar syndrome type II with high unconjugated bilirubin levels that decreased after phenobarbital treatment but increased in adolescence. Four different UGT1A1 gene variants have been identified for this patient, of which one is novel (g.11895-11898del) most likely confirming diagnose molecularly. Conclusions: The presented case highlights the challenges encountered with the interpretation of molecular data upon identification of multiple variants in one gene that are causing different degree reducing effect on enzyme activity leading to several clinical conditions.Peer reviewe

Potential drug-drug interactions between oral anticoagulants for high-risk patients with atrial fibrillation in Latvia

Publisher Copyright: © 2019 Elsevier Science B.V.. All rights reserved.Introduction: Atrial fibrillation (AFib) is a disease that affects many people, especially elderly ones. All of these persons have an increased risk of thromboembolic event. For lowering the risk these patients use anticoagulation therapy. There are two types of oral anticoagulants – vitamin K antagonist warfarin and new, known also as direct oral anticoagulants, dabigatran and rivaroxaban. Due to several comorbidities and other complications, e.g. the risk of bleeding and thromboembolism, AFib patients are using different medication simultaneously, therefore increasing the risk of drug-drug interactions because of one metabolism path through P-glycoprotein and CYP450. Monitoring of medical therapy and patient education about most frequent drug-drug interactions using oral anticoagulants could raise attention of health care professionals to the possible drug-drug interactions and promote safe and effective anticoagulation therapy. Aim: To define and analyze the most common potential drug-drug interactions for most frequent used oral anticoagulants – warfarin, dabigatran, rivaroxaban – in patients with high-risk AFib in Latvia. Materials and methods: Quantitative analytic cross-section research was made in time period from October 2016 till June 2017 in Pauls Stradins clinical university hospital, Center of Cardiology in Latvia. The data about patients with high-risk AFib who used oral anticoagulants daily were selected. After signed patients consent form the demographic data, regularly and frequently used medication and food supplements were obtained. Laboratory analysis and echocardiography data were specified with the help of case anamnesis. For statistical data analysis were used SPSS Statistics database. Results: Altogether 143 patients were enrolled in this study, from which 46.2% were male, 53.8% female, with the mean age 69.7 (SD 9.9) years. 53.8% used warfarin, 16.1% dabigatran and 33.6% used rivaroxaban. 49.7% of patients had increased risk of possible drug-drug interactions. For warfarin users the most frequent potential interactions were with omega-3 supplements (20.8%), amiodarone (16.7%) and proton pump inhibitors (13.8%). For dabigatran users the most frequent potential interaction was with proton pump inhibitors (26.1%), amiodarone (17.4%) and omega-3 supplements (13.0%). For rivaroxaban users the most frequent potential drug interaction was with amiodarone (29.2%), omega-3 supplements (16.7%) and non-steroidal anti-inflammatory drugs (4.2%). Conclusion: From all high-risk AFib patients 47.7% had potentially moderate or major risk of drug interactions, most frequently with food supplements. 50.3% patients used warfarin, K vitamin antagonist. The most frequent potential drug interaction in warfarin group was with omega-3 supplements (20.8%) and amiodarone (16.7%), in dabigatran group with proton pump inhibitors (26.1%) and amiodarone (17.4%), in rivaroxaban group with amiodarone (29.2%) and omega-3 supplements (16.7%). Awareness of these interactions between health care professionals could promote the safety and effectiveness of anticoagulation therapy for high-risk atrial fibrillation patients.publishersversionPeer reviewe

Methods for detection of direct oral anticoagulants and their role in clinical practice

Publisher Copyright: © 2019, ČKS.Introduction: Atrial fi brillation (AF) is the most common arrhythmia that increases by age, doubles for every decade after age of 50 years and reaches about 10% patients ≥ 80 years.1 Despite direct oral anticoagulants' (DOACs') predictable pharmacokinetics and pharmacodynamics, the laboratory tests are necessary for efective and safe medical treatment, also for prediction and detection of thrombotic and bleeding events, as well as in situations when temporary discontinuation could be desirable.2 Aim: The aim of this study was to identify and analyze the need of coagulation tests for AF patients with high cardiovascular risk in clinical practice. Methods: Quantitative, analytic, cross-sectional clinical trial, during the period from October 2016 till June 2017, was performed at Center of Cardiology, Pauls Stradins Clinical University Hospital, Latvia. There were collected data about patients with non-valvular AF, under anticoagulative therapy ≥3 months, defi ned as a high-risk group by CHA2DS2-VASc score - more or equal to 2 or 3, men and women, respectively. Data were analyzed using SPSS. Results: There were collected data about 143 patients of whom 46.2% (n = 66) were male; the mean age was 69.7 (SD ± 9.9) years. About 2/3 (73.1%) of all patients the AF were longer than 1 year. The mean CHA2DS2-VASc score was 4.2 (SD ± 1.5). The most common comorbidities were arterial hypertension (65.0%; 93), chronic heart failure (48.3%; 69), coronary artery disease (32.9%; 47), diabetes mellitus (24.5%; 35), and dyslipidemia (25.9%; 37). Almost half of patients (46.2%; 66) used DOACs, 31.5% rivaroxaban and 14.7% dabigatran, respectively; furthermore, 1.4% patients used DOACs with antiaggregants. 49.7% (71) patients had increased risk of possible drug-drug interactions, most frequently with proton pump inhibitors (16.8%; 24), amiodarone (24.5%; 35), anti-inflammatory drugs (49.0%; 70). The use of DOACs and possible drug-drug interactions increases by risk score, reaching the maximum score 3 (16.1%; 23) and the mean frequent score 4.4 of 86 (60.1%) AF patients, respectively. The drug concentration in blood was lower than expected, reaching about 75.20% of Cmax. Conclusion: DOACs' usage correlates with CHA2DS2-VASc score with mean frequent score 4.4 of 86 (60.1%) AF patients, respectively. Coagulation tests were applicable more than half of patients (60.1%) to detect DOACs concentration in plasma.publishersversionPeer reviewe

X-ray scattering from stepped and kinked surfaces: An approach with the paracrystal model

A general formalism of X-ray scattering from different kinds of surface morphologies is described. Based on a description of the surface morphology at the atomic scale through the use of the paracrystal model and discrete distributions of distances, the scattered intensity by non-periodic surfaces is calculated over the whole reciprocal space. In one dimension, the scattered intensity by a vicinal surface, the two-level model, the N-level model, the faceted surface and the rough surface are addressed. In two dimensions, the previous results are generalized to the kinked vicinal surface, the two-level vicinal surface and the step meandering on a vicinal surface. The concept of crystal truncation rod is generalized considering also the truncation of a terrace by a step (yielding a terrace truncation rod) and a step by a kink (yielding a step truncation rod).Comment: 33 pages, 18 figure

Clopidogrel and the possibility of drug-drug interaction in primary health care

Introduction: Clopidogrel ineffectiveness is a serious problem in antiplatelet therapy. Many factors may contribute to this phenomenon. One of them is clopidogrel drugedrug interaction with CYP2C19 and CYP3A4 enzyme inhibitors. The main goal of this descriptive study was to assess the prevalence of cases of clopidogreledrug interactions in the primary health care physicians' practices. Materials and methods: During 2010e2011, 80 patients receiving clopidogrel antiplatelet therapy from primary care physicians' clinical practices were involved in this study. By using questionnaires and case histories, the following information was collected: Age, gender, clinical diagnoses, and medications used. Results: In the current study, drugs were used that could potentially influence the effect of clopidogrel: Omeprazole, lipophilic statins, calcium channel blockers (CCB). There was a different use of the abovementioned drugs before and after the initiation of the clopidogrel therapy, e.g., 12 (15.0%) and 44 (55.0%) patients used proton pump inhibitors (PPI) before and after the clopidogrel therapy accordingly (P = 0.16; x 2 = 1.91). However, pantoprazole was recommended more often than other PPI. The use of the potential CYP3A4 inhibitors e lipophilic statins and CCB e was increased after the prescription of clopidogrel too. Concomitant use of statins (mainly atorvastatin) with clopidogrel was observed in 75 (93.8%) patients and the use of CCB (mainly amlodipine) e in 33 (41.3%) patients. Conclusion: In the primary health care practices, it is revealed that there is co-medication of clopidogrel with weak CYP3A4 inhibitors, such as lipophilic statins and amlodipine, and with the moderate CYP2C19 inhibitor e omeprazole. The latter co-medication is potentially harmful and it is very important to inform the first care professionals about the opportunity to change omeprazole to pantoprazole, which does not influence clopidogrel biotransformation.publishersversionPeer reviewe

Elastic relaxation during 2D epitaxial growth: a study of in-plane lattice spacing oscillations

The purpose of this paper is to report some new experimental and theoretical results about the analysis of in-plane lattice spacing oscillations during two-dimensional (2D) homo and hetero epitaxial growth. The physical origin of these oscillations comes from the finite size of the strained islands. The 2D islands may thus relax by their edges, leading to in-plane lattice spacing oscillations during the birth and spread of these islands. On the one hand, we formulate the problem of elastic relaxation of a coherent 2D epitaxial deposits by using the concept of point forces and demonstrate that the mean deformation in the islands exhibits an oscillatory behaviour. On the other hand, we calculate the intensity diffracted by such coherently deposited 2D islands by using a mean model of a pile-up of weakly deformed layers. The amplitude of in-plane lattice spacing oscillations is found to depend linearly on the misfit and roughly linearly on the nucleation density. We show that the nucleation density may be approximated from the full-width at half maximum of the diffracted rods at half coverages. The predicted dependence of the in-plane lattice spacing oscillations amplitude with the nucleation density is thus experimentally verified on V/Fe(001), Mn/Fe(001), Ni/Fe(001), Co/Cu(001) and V/V(001).Comment: 39 pages, 10 figure