241 research outputs found

    Riemann boundary value problems in generalized weighted hardy spaces

    Get PDF
    Riemann boundary value problem of analytic function theory in weighted Hardy classes with variable summability index is considered in this work. The Fredholmness of this problem is investigated under certain conditions on coefficients and a weight. The general solution for homogeneous problem is obtained in weighted Hardy classes with variable summability index. In the case where the weight function satisfies the Muckenhoupt condition with variable summability index, the solvability of the non-homogeneous Riemann problem with the right side from the generalized weighted Lebesgue space is studied

    Investigation and performance optimization of mesh networking in Zigbee

    Get PDF
    The aim of this research paper is to perform a detailed investigation and performance optimization of mesh networking in Zigbee. ZigBee applications are open and global wireless technology that are based on IEEE 802.15.4 standard, it is used for sense and control in many fields like, military, commercial, industrial and medical applications. Extending ZigBee lifetime is a high demand in many ZigBee networks industry and applications, and since the lifetime of ZigBee nodes depends mainly on batteries for their power, the desire for developing a scheme or methodology that support power management and saving battery lifetime is of a great requirement. In this research work, a power sensitive routing Algorithm is proposed Power Sensitive Ad hoc On-Demand (PS-AODV) to develop protocol scheme and methodology of existing on-demand routing protocols, by introducing an algorithm that manages ZigBee operations and construct the route from trusted active nodes. Furthermore, many aspects of routing protocol in ZigBee mesh networks have been researched to concentrate on route discovery, route maintenance, neighbouring table, and shortest paths. PS-AODV routing algorithm is used in two different ZigBee mesh networks, with two different coordinator locations, one used at the centre and the other one at the corner of the networks. The extracted results conclude a better network operation for the coordinator located at the centre with an increase in the network lifetime around 20% percentage, and saved about 32.7% of delay time compare to AODV

    Kinetic and in silico analysis of thiazolidin-based inhibitors of Ξ±-carbonic anhydrase isoenzymes.

    Get PDF
    Durdagi, Serdar/0000-0002-0426-0905 WOS: 000314531000019 PubMed: 23173744 Carbonic anhydrases (CAs, EC 4.2.1.1) are inhibited by sulfonamides, inorganic anions, phenols, salicylic acid derivatives (acting as drug or prodrugs). A novel class of CA inhibitors (CAIs), interacting with the CA isozymes I and II (cytosolic) in a different manner, is reported here. Kinetic measurements allowed us to identify thiazolidin-based compounds as submicromolar-low micromolar inhibitors of these two CA isozymes. Molecular docking studies of a set of such inhibitors within CA I and II active site allowed us to understand the inhibition mechanism. This new class of inhibitors bind differently compared to other classes of inhibitors known to date: they were found between the phenol-binding site, filling thus the middle of the enzyme cavity

    Transmission power optimization of high speed 32 channelsΓ—12.8 Tbps CWDM based on multi-span SSMF using RZ modulation format

    Get PDF
    The problem with expand current optical networks while not dynamic infrastructure ends up in adopt the CWDM system with Brobdingnagian information measure and multi-channels. This text examines the twelve.8Tbps over 32-channels, performed in an exceedingly series of laptop simulations with the RZ modulation format on the SSMF line, and its characteristics. The results of the simulation show that knowledge rates will be transferred effectively mistreatment AN economical and economical infrastructure with an honest system performance. The standard optical power rank and therefore the most quality issue for the 32-channels square measure well. The CWDM optical network and its applications will contribute and supply unlimited information measure at a minimum price for all service ranges of fiber optic communication systems like web belongings, and FTTH. CWDM acting a key responsibility in existing and future solutions for optical networks because of its enticing applications

    Attention deficit hyperactivity disorder symptomatology and pediatric obesity: Psychopathology or sleep deprivation?

    Get PDF
    The relationship between attention deficit hyperactivity disorder (ADHD) and obesity in children has received considerable attention in recent years. However, the literature currently overlooks the potential causal and maintaining role that sleep problems may play in this relationship. Using a biopsychosocial framework, this article highlights how sleep problems impact the biological, psychological, and social aspects of both ADHD symptomatology and obesity. An in-depth examination of this model illustrates the imperative need for future research and clinical practice to recognize and explore the role sleep has in the link between obesity and ADHD symptomatology

    How do ecological perspectives help understand schools as sites for teacher learning?

    Get PDF
    Schools are sites of teachers’ professional learning for both new entrants and experienced practitioners. In this paper, schools are conceptualised as complex, multidimensional ecologies that are constituted by the relations that exist between school leaders, teachers, mentors and all members of the school community. As relational environments, the conditions affecting professional learning – both formal and informal – are constantly dynamic, with multiple and simultaneous interactions taking place between these stakeholders. Interactions are also multi-layered – between the school system, individuals, classrooms, the community and the policy environment. School leaders are a major influence on these dynamics and affect how schools act as sites of professional formation, mediating external policy as well as affecting micro-dynamics within individual school systems. The challenge of realising professional learning within these relational contexts can be viewed as a β€˜wicked problem’, a feature of complex systems that resists simplified solutions. In conceptualising a complex ecology at work, we illuminate the relational dynamics with a focus, for all stakeholders within schools, including leaders, on the need to recognise and value the importance of β€˜emergence’ in professional learning. This means embracing inevitable uncertainty as a feature of schools as complex systems

    Analysing the Large Decline in Coronary Heart Disease Mortality in the Icelandic Population Aged 25-74 between the Years 1981 and 2006

    Get PDF
    BACKGROUND: Coronary heart disease (CHD) mortality rates have been decreasing in Iceland since the 1980s. We examined how much of the decrease between 1981 and 2006 could be attributed to medical and surgical treatments and how much to changes in cardiovascular risk factors. METHODOLOGY: The previously validated IMPACT CHD mortality model was applied to the Icelandic population. The data sources were official statistics, national quality registers, published trials and meta-analyses, clinical audits and a series of national population surveys. PRINCIPAL FINDINGS: Between 1981 and 2006, CHD mortality rates in Iceland decreased by 80% in men and women aged 25 to 74 years, which resulted in 295 fewer deaths in 2006 than if the 1981 rates had persisted. Incidence of myocardial infarction (MI) decreased by 66% and resulted in some 500 fewer incident MI cases per year, which is a major determinant of possible deaths from MI. Based on the IMPACT model approximately 73% (lower and upper bound estimates: 54%-93%) of the mortality decrease was attributable to risk factor reductions: cholesterol 32%; smoking 22%; systolic blood pressure 22%, and physical inactivity 5% with adverse trends for diabetes (-5%), and obesity (-4%). Approximately 25% (lower and upper bound estimates: 8%-40%) of the mortality decrease was attributable to treatments in individuals: secondary prevention 8%; heart failure treatments 6%; acute coronary syndrome treatments 5%; revascularisation 3%; hypertension treatments 2%, and statins 0.5%. CONCLUSIONS: Almost three quarters of the large CHD mortality decrease in Iceland between 1981 and 2006 was attributable to reductions in major cardiovascular risk factors in the population. These findings emphasize the value of a comprehensive prevention strategy that promotes tobacco control and a healthier diet to reduce incidence of MI and highlights the potential importance of effective, evidence based medical treatments

    Sustained Na<sup>+</sup>/H<sup>+</sup> exchanger activation promotes gliotransmitter release from reactive hippocampal astrocytes following oxygen-glucose deprivation

    Get PDF
    Hypoxia ischemia (HI)-related brain injury is the major cause of long-term morbidity in neonates. One characteristic hallmark of neonatal HI is the development of reactive astrogliosis in the hippocampus. However, the impact of reactive astrogliosis in hippocampal damage after neonatal HI is not fully understood. In the current study, we investigated the role of Na +/H+ exchanger isoform 1 (NHE1) protein in mouse reactive hippocampal astrocyte function in an in vitro ischemia model (oxygen/glucose deprivation and reoxygenation, OGD/REOX). 2 h OGD significantly increased NHE1 protein expression and NHE1-mediated H+ efflux in hippocampal astrocytes. NHE1 activity remained stimulated during 1-5 h REOX and returned to the basal level at 24 h REOX. NHE1 activation in hippocampal astrocytes resulted in intracellular Na+ and Ca2+ overload. The latter was mediated by reversal of Na+/Ca2+ exchange. Hippocampal astrocytes also exhibited a robust release of gliotransmitters (glutamate and pro-inflammatory cytokines IL-6 and TNFΞ±) during 1-24 h REOX. Interestingly, inhibition of NHE1 activity with its potent inhibitor HOE 642 not only reduced Na+ overload but also gliotransmitter release from hippocampal astrocytes. The noncompetitive excitatory amino acid transporter inhibitor TBOA showed a similar effect on blocking the glutamate release. Taken together, we concluded that NHE1 plays an essential role in maintaining H + homeostasis in hippocampal astrocytes. Over-stimulation of NHE1 activity following in vitro ischemia disrupts Na+ and Ca2+ homeostasis, which reduces Na+-dependent glutamate uptake and promotes release of glutamate and cytokines from reactive astrocytes. Therefore, blocking sustained NHE1 activation in reactive astrocytes may provide neuroprotection following HI. Β© 2014 Cengiz et al

    Capric Acid Secreted by S. boulardii Inhibits C. albicans Filamentous Growth, Adhesion and Biofilm Formation

    Get PDF
    Candidiasis are life-threatening systemic fungal diseases, especially of gastro intestinal track, skin and mucous membranes lining various body cavities like the nostrils, the mouth, the lips, the eyelids, the ears or the genital area. Due to increasing resistance of candidiasis to existing drugs, it is very important to look for new strategies helping the treatment of such fungal diseases. One promising strategy is the use of the probiotic microorganisms, which when administered in adequate amounts confer a health benefit. Such a probiotic microorganism is yeast Saccharomyces boulardii, a close relative of baker yeast. Saccharomyces boulardii cells and their extract affect the virulence factors of the important human fungal pathogen C. albicans, its hyphae formation, adhesion and biofilm development. Extract prepared from S. boulardii culture filtrate was fractionated and GC-MS analysis showed that the active fraction contained, apart from 2-phenylethanol, caproic, caprylic and capric acid whose presence was confirmed by ESI-MS analysis. Biological activity was tested on C. albicans using extract and pure identified compounds. Our study demonstrated that this probiotic yeast secretes into the medium active compounds reducing candidal virulence factors. The chief compound inhibiting filamentous C. albicans growth comparably to S. boulardii extract was capric acid, which is thus responsible for inhibition of hyphae formation. It also reduced candidal adhesion and biofilm formation, though three times less than the extract, which thus contains other factors suppressing C. albicans adherence. The expression profile of selected genes associated with C. albicans virulence by real-time PCR showed a reduced expression of HWP1, INO1 and CSH1 genes in C. albicans cells treated with capric acid and S. boulardii extract. Hence capric acid secreted by S. boulardii is responsible for inhibition of C. albicans filamentation and partially also adhesion and biofilm formation
    • …
    corecore