108 research outputs found

    Development of Myxobolus dispar (Myxosporea : Myxobolidae) in an oligochaete alternate host, Tubifex tubifex

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    The development of Myxobolus dispar Thelohan, 1895, a myxosporean parasite of the gills of common carp (Cyprinus carpio L.) was studied in experimentally infected oligochaetes Tubifex tubifex Muller. After infection of uninfected tubificids with mature spores of M. dispar development of actinosporean stages was first observed light microscopically 21 days after initial exposure. In histological sections, early pansporocysts were located in the gut epithelium of experimental oligochaetes, while advanced stages occupied mostly the outer layers of the gut and the coelozoic space. Mature pansporocysts, each containing 8 raabeia spores, appeared 199 days after initial exposure. Following damage of the intestinal wall and rupture of the pansporocysts, free actinosporean stages were found in the gut lumen of the oligochaetes. Actinospores of M. dispar emerged from the worms after 217 days of intra-oligochaete development. They were floating in the water and showed a unique raabeia form. Each raabeia sport had three pyriform polar capsules and a cylindrical-shaped sporoplasm with approximately 32 secondary cells. The spore body joined the three caudal projections without a style. Caudal projections were bifurcated at the end and the two main branches had further small bifurcations. The total length of the raabeia sport was approximately 158 mu m. The prevalence of infection in 240 experimentally infected Tubifex specimens was 99.2%. No infection was found in the control oligochaetes

    Spectral Data for Generation of Molecular Complexity from Cyclooctatetraene: Preparation of Optically Active Protected Aminocycloheptitols and Bicyclo[4.4.1]undecatriene

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    Spectral data created in the course of the research project. Supports specific findings in Generation of Molecular Complexity from Cyclooctatetraene: Preparation of Optically Active Protected Aminocycloheptitols and Bicyclo[4.4.1]undecatriene . The racemic (6-cyclo-heptadienyl)Fe(CO)3+ cation ((±)-7), prepared from cyclooctatetraene, was treated with a variety of carbon and heteroatom nucleophiles. Attack took place at the less hindered C1 dienyl carbon and decomplexation of the (cycloheptadiene)Fe(CO)3 complexes gave products rich in functionality for further synthetic manipulation. In particular, a seven-step route was developed from racemic (6-styryl-2,4-cycloheptadien-1-yl)phthalimide ((±)-9 d) to afford the optically active aminocycloheptitols (−)-20 and (+)-20

    Sprectral data for Generation of Molecular Complexity from Cyclooctatetraene Using Dienyliron and Olefin Metathesis

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    Spectral data used in the course of researching Generation of molecular complexity from cyclooctatetraene using dienyliron and olefin metathesis methodology . Transformation of the simple hydrocarbon cyclooctatetraene into a variety of polycyclic skeletons was achieved by sequential coordination to iron, reaction with electrophiles followed by allylated nucleophiles, decomplexation and olefin metathesis

    Development of Thelohanellus hovorkai and Thelohanellus nikolskii (Myxosporea : Myxozoa) in oligochaete alternate hosts

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    The development of Thelohanellus hovorkai, a myxosporean parasite of the connective tissues, and Thelohanellus nikolskii, a fin and scale parasite of common carp (Cyprinus carpio) was studied in experimentally infected oligochaetes Branchiura sowerbyi and Tubifex tubifex, respectively. After infection with mature spores of T. hovorkai, the development of actinosporean stages was first observed light microscopically in the gut of Branchiura sowerbyi 93 days after infection. Free actinospores of T. hovorkai were found in the lumen of the oligochaete's gut 101 days after infection. They were floating in water and showed a typical aurantiactinomyxon form. At 18-22 degrees C, aurantiactinomyxon spores of T. hovorkai emerged from the worms 104 days after infection. The development of T. nikolskii was examined in Tubifex tubifex, from which aurantiactinomyxon spores were released 60 days after infection at 22-24 degrees C. The diameter of spore body was 18.6 mu m and the lenght of caudal processes 29 mu m for T. hovorkai, while 21.1 mu m and 13.4 mu m for T. nikolskii, respectively. The prevalence of aurantiactinomyxon infection in B. sowerbyi for T. hovorkai proved to be 16.7%, while in T. tubifex for T. nikolskii it was 12.5%

    Neutrophil-surface antigens CD11b and CD64 expression: a potential predictor of early-onset neonatal sepsis

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    Background: CD11b, an α subunit of the ÎČ2 integrin adhesion molecule, and CD64, the high affinity FcÎł receptor I, are specific neutrophil-surface antigens activated in response to systemic inflammation and, hence, they might potentially help identifying neonatal infections. Objective: We sought to evaluate the time course of expression and diagnostic and prognostic utility of CD11b and CD64 in early-onset sepsis in the suspected newborn. Methods: Sixty newborn infants (28-40 weeks gestation) with antenatal risk factors for sepsis were enrolled and subjected to sepsis work-up including complete blood count, quantification of serum C reactive protein (CRP) and flow cytometric analysis of CD11b and CD64 in cord blood (0 h). These tests were repeated at 8, 24 and 48 h postnatally. Neonates were defined, retrospectively, in two groups: sepsis and no infection, on basis of clinical observation over their first five postnatal days and sepsis work-up results. Results: A significant enhancement of neutrophil CD11b and CD64 expression was demonstrated in the sepsis group as compared to the non-infected group. CD11b over-expression had an onset at 0 h. Its mean value approached two-fold mean level of non-infected neonates by 8-24 h, and declined thereafter. CD64 rising onset was detectable at 8 h and its mean percentage reached four-fold mean value of the non-infected group at 24 h. At 24 h, an optimal cut-off value for CD11b expression of 35% (sensitivity 80%, and specificity 100%), and for CD64 expression of 17% (sensitivity 88%, and specificity 90.3%) had the best performance for prediction of sepsis. Combined use of both markers at 24 h yielded 90% sensitivity and 95% specificity for sepsis prediction. Sepsis survivors showed significantly lower mean expression for CD11b and CD64 as compared to those with fatal outcome. At 24 h, a cut-off value of 88% expression for CD11b and 50% expression for CD64 predicted mortality with sensitivity and specificity of 100%. Conclusion: Enhanced expression of neutrophil-surface antigens CD11b and CD64 could be a promising tool for prediction and therapeutic decision-making in early-onset sepsis indicating the necessity of initiation of antimicrobial therapy and reduction of its unnecessary use in non-infected neonates even before definitive microbiologic identification.Keywords: sepsis, neonate, early-onset, neutrophil activation, surface antigen, CD11b, CD64Egypt J Pediatr Allergy Immunol 2004; 2(2): 90-10

    Grid impedance estimation for islanding detection and adaptive control of converters

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    The grid impedance is time varying due to the changing structure of the power system configuration and it can have a considerable influence on the control and stability of grid connected converters. This paper presents an online grid impedance estimation method using the output switching current ripple of a SVPWM based grid connected converter. The proposed impedance estimation method is derived from the discretised system model using two consecutive samples within the switching period. The estimated impedance is used for islanding detection and online current controller parameter adaptation. Theoretical analysis and MATLAB simulation results are presented to verify the proposed method. The effectiveness of the grid impedance estimator is validated using experimental results

    Biochemical, physiological, and molecular responses of diverse olive cultivars to different irrigation regimes

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    Olive is an essential industrial crop in the Mediterranean region with valuable economic and agricultural concerns. Despite its drought resistance, its productivity is restricted by extreme drought stress. Olive cultivars display considerable variation in response mechanisms to drought stress. Accordingly, the impact of mild and extreme water deprivation over two seasons compared to full irrigation requirements on growth and physiological characteristics of three diverse olive cultivars. Three olive cultivars, ‘Manzanillo’, ‘Eggizi-Shami’, and ‘Tofaahi’, were evaluated under three irrigation regimes 100% ETc, 75% ETc, and 50% ETc. Characteristics of shoot and root, as well as physio-chemical constituents, were determined. Besides, the gene expression of dehydration-responsive element binding (DREB), dehydrin (DHN), and catalase (CAT) genes in olive cultivars were explored under different irrigation regimes. The results indicated a substantial impact of irrigation level on all studied parameters. The mild and extreme drought stress treatments caused a gradual reduction in nitrogen, phosphorus, and potassium content, relative water content, root and shoot length, root and leaf numbers, branch count, and leaf area across both seasons. Conversely, proline content was considerably increased under drought treatments compared to well-watered conditions. Similarly, the assessed cultivars exhibited significant variation in all studied parameters, with ‘Eggizi-Shami’ demonstrating superiority. Under mild and extreme drought stress conditions, the cultivar ‘Eggizi-Shami’ displayed the highest proline content and most growth characteristics. Besides, the real-time quantitative PCR (RT-qPCR) analysis displayed significant alterations in gene expression of the tested three genes related to drought response (DHN, DREB, and CAT). The RT-qPCR analysis revealed that under drought stress conditions (75% and 50% ETc), ‘Eggizi-Shami’ exhibited higher expression compared to the other two cultivars (‘Tofaahi’ and ‘Manzanillo’). Combining the results of morphological and physiological parameters with gene expression analysis of drought-related genes can offer highly validated information about drought-tolerant olive cultivars. This integrated approach serves as an innovative methodology to identify and confirm genes involved in abiotic stress

    Generation of Molecular Complexity from Cyclooctatetraene: Preparation of Optically Active Protected Aminocycloheptitols and Bicyclo[4.4.1]undecatriene

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    The racemic (6-cyclo-heptadienyl)Fe(CO)3+ cation ((±)-7), prepared from cyclooctatetraene, was treated with a variety of carbon and heteroatom nucleophiles. Attack took place at the less hindered C1 dienyl carbon and decomplexation of the (cycloheptadiene)Fe(CO)3 complexes gave products rich in functionality for further synthetic manipulation. In particular, a seven-step route was developed from racemic (6-styryl-2,4-cycloheptadien-1-yl)phthalimide ((±)-9 d) to afford the optically active aminocycloheptitols (−)-20 and (+)-20

    Generation of Molecular Complexity from Cyclooctatetraene Using Dienyliron and Olefin Metathesis Methodology

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    Transformation of the simple hydrocarbon cyclooctatetraene into a variety of polycyclic skeletons was achieved by sequential coordination to iron, reaction with electrophiles followed by allylated nucleophiles, decomplexation and olefin metathesis
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