213 research outputs found

    Fractal Newton Methods

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    We introduce fractal Newton methods for solving (Formula presented.) that generalize and improve the classical Newton method. We compare the theoretical efficacy of the classical and fractal Newton methods and illustrate the theory with examples

    Effects of different irrigation intervals and fertilizer applications on certain chemical contents of ‘Braeburn’ apple cultivar

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    The aim of present study was to investigate effects of different irrigation intervals and fertilizers on total lipid, fatty acid and sugar accumulation of Braeburn apple cultivar under Mediterranean climatic conditions. Irrigation program was performed for two consecutive years with three different intervals (1, 3 and 7 days). In fertilization, 40 g N, 32 g P2O5 and 80 g K2O per tree (with four replications) applied in the same doses for both years, except for the increased N (50 g per tree) for second year, considering the vegetative growth of the trees. The fruits were commercially harvested in 2006 season. The lipid content ranged from 0.22% (daily irrigation without fertilizer) to 0.70% (irrigation in 7 days intervals with fertilizer). The highest fatty acid was obtained from treatment 3 (irrigation in 3 days intervals without fertilizer) (83.95%), while the treatment 6 provided the least value with 64.08% (irrigation in 7 days intervals with fertilizer). Although certain changes on fructose, glucose, sucrose and total sugars content were detected, the differences were not statistically significantly among the treatments

    Observer based chaotic message transmission

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    We consider observer based synchronization of continuous-time chaotic systems. We present two message transmission schemes for such systems. The first one is based on chaotic masking and modulation, and the second one is based on only chaotic modulation. We show that in these schemes, the message may be recovered under certain conditions. We show that the proposed schemes are robust with respect to noise and parameter mismatch. We also present some simulation results

    Thermal Analyses for Induction Sintering of Powder Metal Compacts up to Sintering Temperature

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    Induction sintering is developed as an alternative method to conventional sintering in order to sinter iron-based powder metal (PM) compacts. In this study, the 12 kW power and 30 kHz frequency induction-sintering machine is used for 3 wt.% copper-mixed iron. The effects of different shapes and sizes of the induction coil, and temperature differences on the PM compacts up to sintering temperature are investigated; these parameters are determined both theoretically and experimentally during induction sintering. Iron-based PM compacts are sintered at 1120°C. Induction sintering of iron-based PM compacts are simulated using a program to examine the effects of magnetic flux and temperature distribution in the sample over time. The results are compared with the experimental studies.Индукционное спекание было разработано как альтернатива обычному спеканию, чтобы спекать прессовки порошковых материалов (ПМ) на основе железа. В данной работе использована индукционная агломерационная машина мощностью 12 кВт и частотой 30 кГц для спекания смеси железа с 3 масс.% меди. Исследованы влияния различных форм и размеров индукционных катушек, разниц температур на брикеты ПМ вплоть до температуры спекания; эти параметры были исследованы как теоретически, так и экспериментально во время индукционного спекания. Брикеты ПМ на основе железа спекались при 1120°C. Индукционное спекание брикетов ПМ на основе железа также смоделировано с использованием программы, которая исследует влияние магнитного потока и распределения температуры в образце со временем. Результаты сопоставлены с результатами экспериментальных исследований.Індукційне спікання було розроблено як альтернатива звичайному спіканню, щоб спікати брикети порошкових матеріялів (ПМ) на основі заліза. В даній роботі використано індукційну аґломераційну машину потужністю у 12 кВт і частотою у 30кГц для спікання суміші заліза з 3 ваг.% міді. Досліджено впливи різних форм і розмірів індукційної шпулі, ріжниць температур на брикети ПМ аж до температури спікання; ті параметри було досліджено як теоретично, так й експериментально під час індукційного спікання. Брикети ПМ на основі заліза спікалися при 1120°C. Індукційне спікання брикетів ПМ на основі заліза також модельовано з використанням програми, яка досліджує впливи магнетного потоку та розподілу температури у зразку з часом. Результати порівняно з результатами експериментальних досліджень

    Afferent specific role of NMDA receptors for the circuit integration of hippocampal neurogliaform cells.

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    This is the final version of the article. Available from Nature Publishing Group via the DOI in this record.Appropriate integration of GABAergic interneurons into nascent cortical circuits is critical for ensuring normal information processing within the brain. Network and cognitive deficits associated with neurological disorders, such as schizophrenia, that result from NMDA receptor-hypofunction have been mainly attributed to dysfunction of parvalbumin-expressing interneurons that paradoxically express low levels of synaptic NMDA receptors. Here, we reveal that throughout postnatal development, thalamic, and entorhinal cortical inputs onto hippocampal neurogliaform cells are characterized by a large NMDA receptor-mediated component. This NMDA receptor-signaling is prerequisite for developmental programs ultimately responsible for the appropriate long-range AMPAR-mediated recruitment of neurogliaform cells. In contrast, AMPAR-mediated input at local Schaffer-collateral synapses on neurogliaform cells remains normal following NMDA receptor-ablation. These afferent specific deficits potentially impact neurogliaform cell mediated inhibition within the hippocampus and our findings reveal circuit loci implicating this relatively understudied interneuron subtype in the etiology of neurodevelopmental disorders characterized by NMDA receptor-hypofunction.Proper brain function depends on the correct assembly of excitatory and inhibitory neurons into neural circuits. Here the authors show that during early postnatal development in mice, NMDAR signaling via activity of long-range synaptic inputs onto neurogliaform cells is required for their appropriate integration into the hippocampal circuitry.We thank Daniel Abebe for mouse colony maintenance and Kurt Auville for additional assistance with confocal imaging. We thank UNC Vector Core and Ed Boyden, MIT, Cambridge, MA, USA for generously providing AAV9-syn-Chrimson-TdTomato and AAV9-syn-Chronos-GFP. This work was supported by an intramural award to C.J.M. from the Eunice Kennedy–Shriver National Institute of Child Health and Human Development and a Competitive Fellowship Award to J.C.W. from the National Institute of Neurological Disorders and Strok

    Pharmacological Properties of Edible Asparagus acutifolius and Asparagus officinalis Collected from North Iraq and Turkey (Hatay)

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    In this study, antioxidant, oxidant, antimicrobial, and antiproliferative activities of Asparagus acutifolius L. and Asparagus officinalis L., known for their nutritional properties, were determined. In this context, methanol (MeOH) and dichloromethane (DCM) extracts of plants were obtained. Total antioxidant status (TAS), total oxidant status (TOS), and oxidative stress index (OSI) were determined using Rel Assay kits. Antimicrobial activities of plant extracts were determined against the test microorganisms using the agar dilution method. Antiproliferative activity was tested on the lung cancer cell line A549. As a result of the studies, it has been determined that the plant species have high antioxidant potential. In addition, it was observed that the antifungal potentials of plant extracts are high. Antiproliferative activity was determined to be at high level in both plant species. As a result, it has been determined that A. acutifolius and A. officinalis have medical potential and can be used as natural agents in pharmacological designs

    Nitric oxide biosensor uncovers diminished ferrous iron-dependency of cultured cells adapted to physiological oxygen levels

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    Iron is an essential metal for cellular metabolism and signaling, but it has adverse effects in excess. The physiological consequences of iron deficiency are well established, yet the relationship between iron supplementation and pericellular oxygen levels in cultured cells and their downstream effects on metalloproteins has been less explored. This study exploits the metalloprotein geNOps in cultured HEK293T epithelial and EA.hy926 endothelial cells to test the iron-dependency in cells adapted to standard room air (18 kPa O2) or physiological normoxia (5 kPa O2). We show that cells in culture require iron supplementation to activate the metalloprotein geNOps and demonstrate for the first time that cells adapted to physiological normoxia require significantly lower iron compared to cells adapted to hyperoxia. This study establishes an essential role for recapitulating oxygen levels in vivo and uncovers a previously unrecognized requirement for ferrous iron supplementation under standard cell culture conditions to achieve geNOps functionality.Integration Projects of Sabanci University ; Heart Research U.K. ; British Heart Foundation ; European Cooperation in Science and Technology (COST) ; King's Together Strategic Awar

    HPV16 Oncoproteins Induce MMPs/RECK-TIMP-2 Imbalance in Primary Keratinocytes: Possible Implications in Cervical Carcinogenesis

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    Cervical cancer is the third most common cancer in women worldwide. Persistent infection with high-risk HPV types, principally HPV16 and 18 is the main risk factor for the development of this malignancy. However, the onset of invasive tumor occurs many years after initial exposure in a minority of infected women. This suggests that other factors beyond viral infection are necessary for tumor establishment and progression. Tumor progression is characterized by an increase in secretion and activation of matrix metalloproteinases (MMPs) produced by either the tumor cells themselves or tumor-associated fibroblasts or macrophages. Increased MMPs expression, including MMP-2, MMP-9 and MT1-MMP, has been observed during cervical carcinoma progression. These proteins have been associated with degradation of ECM components, tumor invasion, metastasis and recurrence. However, few studies have evaluated the interplay between HPV infection and the expression and activity of MMPs and their regulators in cervical cancer. We analyzed the effect of HPV16 oncoproteins on the expression and activity of MMP-2, MMP-9, MT1-MMP, and their inhibitors TIMP-2 and RECK in cultures of human keratinocytes. We observed that E7 expression is associated with increased pro-MMP-9 activity in the epithelial component of organotypic cultures, while E6 and E7 oncoproteins co-expression down-regulates RECK and TIMP-2 levels in organotypic and monolayers cultures. Finally, a study conducted in human cervical tissues showed a decrease in RECK expression levels in precancer and cancer lesions. Our results indicate that HPV oncoproteins promote MMPs/RECK-TIMP-2 imbalance which may be involved in HPV-associated lesions outcome
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