875 research outputs found

    On the risk of extinction of a wild plant species through spillover of a biological control agent: analysis of an ecosystem compartment model

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    Invasive plant species can be controlled by introducing one or more of their natural enemies (herbivores) from their native range; however such introduction entails the risk that the introduced natural enemy will attack indigenous plant species in the area of introduction. The effect of spillover of a natural enemy from a managed ecosystem compartment (agriculture) in the area of introduction to a natural compartment (non-managed) in which an indigenous plant species is attacked by the introduced natural enemy, whereas another indigenous plant species, which competes with the first, is not attacked, has been studied. The combination of competition and herbivory may result in extinction of the attacked wild plant species. Using a modelling approach, the authors have determined model parameters that characterize the risk of extinction. The findings point to the importance of spillover and the relative attack rates (specificity) of introduced natural enemies with respect to target and non-target plant specie

    Middle Cerebral Artery Stenosis Associated with Moyamoya Pattern Collateralization

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    Background and Purpose: Moyamoya disease is a well described phenomenon. This pattern of collateralization associated with isolated middle cerebral artery stenosis and the natural history of this entity have not been well described. Methods: Cerebral angiograms and CT angiograms performed between August 2004 and August of 2006 demonstrating moyamoya collateralization were retrospectively reviewed. All cases of middle cerebral artery stenosis associated with a rete pattern of collateralization were included in this series. Demographic, clinical, and angiographic data were obtained. Results: There were three cases of middle cerebral artery stenosis associated with a moyamoya pattern of collateralization. The average age of the patients was 36-years old, 2 were male, and all were Caucasian. All patients presented with ischemic symptoms. The average degree of stenosis was 91%. No stenosis was seen in the supraclinoid internal carotid arteries or elsewhere in the intracranial vasculature. Conclusion: We describe an unusual pattern of anastomosis associated with isolated severe middle cerebral artery stenosis or occlusion in Caucasians

    Diagnosis of premature rupture of membranes by the detection of thyroid hormones in vaginal secretions

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    Background: Premature rupture of membranes (PROM) and preterm PROM (PPROM) are the rupture of the fetal chorioamniotic membranes before the onset of labor contractions. Objectives: To evaluate whether detection of thyroid hormones in vaginal washouts can be used to diagnose premature rupture of membranes (PROM). Patients and Methods: Total T4 (thyroxin), total T3 (triiodothyronine), and free T4 concentrations in vaginal washouts were analyzed in 45 women with the diagnosis of PROM and compared with 45 normal pregnancies (controls). A Student�s t-test was used for comparison of thyroid hormone values and a ROC curve was used for analyzing the diagnostic accuracy Results: There were no differences between the patients with PROM and the control women regarding maternal age, gestational age, and parity. The mean concentration of total T4 in the PROM group and the control subjects were 2.1 ± 1.3 jig/mL and 1.55 ± 0.58 jig/, respectively (P = 0.01). Total T3 concentration in the PROM group was significantly higher compared to the controls (1.28 ± 0.42 ng/ vs. 0.8 ± 0.26 ng/, P < 0.0001). Also, free T4 concentration was significantly higher in the PROM group as compared with the controls (0.026 ± 0.034 ng/ vs.0.007 ± 0.004 ng/, P < 0.0001). The ROC curve analysis showed that total T4=1.685 jig/ had a sensitivity of 62, specificity of 76, positive predictive value (PPV) of 71.8, and negative predictive value (NPV) of 66.7. Total T3 = 0.82 ng/ gave a sensitivity of 91, specificity of 64, PPV of 72, and NPV of 87.8. Free T4 = 0.01 ng/ gave a sensitivity of 51, specificity of 82, PPV of 74.2, and NPV of 62.7. The best cutoff values were total T4 = 1.685 ng/, total T3 = 0.82 ng/, and free T4 = 0.01 ng/. Conclusions: Detecting total T4, total T3, and free T4 in vaginal washouts of patients suspected of PROM suspected is a simple, available, rapid, and inexpensive method for the diagnosis of PROM. However, a combination of three tests is recommended. © 2015, Shiraz University of Medical Sciences

    Psychological disorders inwomen with spontaneous preterm delivery

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    Background: Preterm delivery is a major cause of mortality in infants. The prevalence of preterm delivery is rising over time. Psychological disorders have been associated with preterm delivery. In this study, we aimed to compare the frequency of psychological disorders among women with spontaneous preterm versus term delivery. Methods: In this cross-sectional study, psychological disorders in 60 women, who experienced spontaneous term delivery and in 60 women who had spontaneous preterm delivery (gestational age of less than 37 weeks) were examined, using symptom checklist-90-revised questionnaire (SCL-90-R) in Akbarabadi teaching hospital during 2014. The question scales were compared between the two groups, using Chi 2 test and independent t-test. Results: The mean age of the participants was 23.58±4.26, and 23.90±4.71 in preterm-delivery and term-delivery groups, respectively (P value = 0.22). The mean score of Symptom checklist-90-revised questionnaire (SCL-90-R) was 102.21 (±35.81) in women with preterm delivery, and it was 59.14±22.17 in women with term delivery, which was significantly different (P value < 0.001). In addition, the total score and the score for all the subscales of psychological disorder were higher in women with preterm delivery (P value < 0.001). Conclusions: Psychological disorders in pregnancy are associated with an increased risk of preterm delivery. Therefore, future studies should focus on finding ways to lower psychological disorders in late pregnancy. © 2016, Shiraz University of Medical Sciences

    Risk factors and consequent outcomes of placenta previa: Report from a referral center

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    Because of an unknown factor, the frequency of complicated pregnancy with placenta previa has been raised during past decade. This study was designed to deepen our understanding of risk factors and outcomes of placenta previa in our country. This study investigated 694 cases of placenta previa comparing with 600 healthy pregnant women with not overlie placenta in two referral and tertiary Obstetrics and Gynecological Hospital in Iran on the basis of the clinical and para-clinical analysis, in order to find the probable risk factors for occurrence of placenta previa and its effect on maternal and neonatal complications. The most important risk factor for the occurrence of placenta previa was advanced maternal age (P<0.001) and history of stillbirth (OR=117.2, CI=58.3-236.0). In the other hand, the most substantial outcome of this disorder was a reduction of gestational age (P<0.001) and low birth weight neonatally (P<0.001). The conservative follow-up should be programmed for women with placenta previa based on the type of risk factors which can provide the best possible management to decrease the morbidity and mortality of their related complications. © 2016 Tehran University of Medical Sciences. All rights reserved

    Nano-Size Layered Manganese-Calcium Oxide as an Efficient and Biomimetic Catalyst for Water Oxidation Under Acidic Conditions: Comparable To Platinum

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    Inspired by Nature's catalyst, a nano-size layered manganese-calcium oxide showed a low overvoltage for water oxidation in acidic solutions, which is comparable to platinum.Institute for Advanced Studies in Basic Sciences and the National Elite FoundationUS Department of Energy, Office of Basic Energy Sciences, Division of Chemical, Geochemical and Biological Sciences DE-FG02-86ER13622, DE-FG0209ER16119Russian Foundation for Basic Research 11-04-01389a, 12-0492101a, 13-04-92711aMolecular and Cell Biology Programs of the Russian Academy of SciencesCenter for Electrochemistr

    Two knots in an umbilical cord with seventy centimeter length: A case report

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    Our case was a newborn with two umbilical knots that delivered 39 weeks gastation and did not experience any developmental disruptions. The risk factors of fetus for true knot formation in the umbilical cord were gender and the umbilical cord size. © 2020 The Authors. Clinical Case Reports published by John Wiley & Sons Ltd

    The impact of cardiovascular risk factors on the site and extent of coronary artery disease

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    Background: In patients with coronary artery disease (CAD), the site and extent of coronary artery involvement in terms of proximal versus distal stenosis and multi- versus single-vessel disease have a crucial effect on patients' outcome. This study was designed to evaluate the relationship between cardiovascular risk factors and the site and extent of coronary artery involvement. Methods: In this study of patients who had undergone coronary angiography in our hospital, 125 with proximal lesions were enrolled as the case group (group 1) and an equal ageand gender-matched number of patients with non-proximal lesions were selected as the control group (group 2). The two groups were compared based on the presence or absence of diabetes mellitus (DM), hypercholesterolaemia, hypertriglyceridaemia, hypertension (HTN) and cigarette smoking. Results: The frequency of DM was 33.6 and 10.4 in the case and control groups, respectively, which was statistically significant (p < 0.0001). However, the frequency of hypercholesterolaemia in the case and control groups was 30.4 and 29.6 (p = 0.89), respectively; for hypertriglyceridaemia it was 19.2 and 16.8 (p = 0.062), respectively; for HTN it was 33.6 and 28.8 (p = 0.4), respectively; and for cigarette smoking it was 28.8 and 39.2 (p = 0.08), respectively, which were not statistically significant. Diabetic patients compared to non-diabetics had more multi-vessel disease (89.1 vs 61, p < 0.0001, respectively), which was statistically significant. There was no relationship between hypercholesterolaemia, hypertriglyceridaemia, HTN and cigarette smoking and extent (multi-vessel involvement) of CAD (p = NS). Conclusion: Proximal and multi-vessel involvement of the coronary arteries in patients with CAD was related to a history of DM but not of hypercholesterolaemia, HTN, cigarette smoking and hypertiglyceridaemia
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