313 research outputs found

    Reduction of the nonlinear phase shift induced by stimulated Brillouin scattering for bi-directional pumping configuration system using particle swarm optimization algorithm

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    We present a theoretical analysis of an additional nonlinear phase shift of backward Stokes wave based on stimulated Brillouin scattering in the system with a bi-directional pumping scheme. We optimize three parameters of the system: the numerical aperture, the optical loss and the pumping wavelength to minimize an additional nonlinear phase shift of backward Stokes waves due to stimulated Brillouin scattering. The optimization is performed with various Brillouin pump powers and the optical reflectivity values are based on the modern, global evolutionary computation algorithm, particle swarm optimization. It is shown that the additional nonlinear phase shift of backward Stokes wave varies with different optical fiber lengths, and can be minimized to less than 0.07 rad according to the particle swarm optimization algorithm for 5 km. The bi-directional pumping configuration system is shown to be efficient when it is possible to transmit the power output to advanced when frequency detuning is negative and delayed when it is positive, with the optimum values of the three parameters to achieve the reduction of an additional nonlinear phase shift

    Synthesis, Characterization and Antitumor Activity of Some New Oganotellurium Compounds Containing Azomethine Group, Part One

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    New tellurated schiff bases were synthesized by the reaction of the corresponding mercurated Schiff  bases compounds A1-A3 with tellurium tetrabromide in 1:1 mole ratio and  that  gave organyltellurium tribromides  A4-A6.  On the other hand, when mercurated schiff bases and tellurium tetrabromide brought  together in 2:1 mole ratio gave diorganyltellurium dibromides compounds A10-A12 followed by reduction with hydrazine hydrate gave new diorganyl tellurides A13-A15.  Reduction of compounds A4-A6 by  hydrazine hydrate gave new ditellurides A7-A9.  All compounds were characterized by elemental analysis, IR, 1H , 13C NMR, HSQC-NMR and mass spectra.  Invitro anti-tumor bioactivity of some compounds were tested.Â

    The need for sustainable local management to solve the reality of increasing traffic congestions in Iraq

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    The need to find solutions based on sustainable methods for the transportation sector in Iraq has become an urgent necessity due to the ever-increasing volume of traffic congestion caused mainly by the increase in the number of vehicles and the total dependence on them for transportation in the absence of other alternatives. This increase in traffic congestion drains all of the fossil energy in addition to losses in time, health and comfort of users and those close to the roads. Also, it increases the costs in maintaining roads and vehicles, as well as the harmful effects on the environment. A number of literatures have been studied to explain the effects and causes of traffic congestion, especially in countries whose conditions are similar to Iraq. The roads and intersections in the city of Baghdad were monitored, and a number of experts were requested to discuss the causes. A sample questionnaire was conducted that included several levels and ages of Iraqi society to determine the sample's impression on a number of points affecting the local traffic congestion in Baghdad city. It was revealed through the questionnaire that there are four main causes for traffic congestion and there is a strong desire among Iraqis to own and drive vehicles, which led to a significant and continuous increase in their numbers, and this is one of the main causes of congestion

    The molecular genetic analysis of the expanding pachyonychia congenita case collection

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    BACKGROUND: Pachyonychia congenita (PC) is a rare autosomal dominant keratinizing disorder characterized by severe, painful, palmoplantar keratoderma and nail dystrophy, often accompanied by oral leucokeratosis, cysts and follicular keratosis. It is caused by mutations in one of five keratin genes: KRT6A, KRT6B, KRT6C, KRT16 or KRT17. OBJECTIVES: To identify mutations in 84 new families with a clinical diagnosis of PC, recruited by the International Pachyonychia Congenita Research Registry during the last few years. METHODS: Genomic DNA isolated from saliva or peripheral blood leucocytes was amplified using primers specific for the PC-associated keratin genes and polymerase chain reaction products were directly sequenced. RESULTS: Mutations were identified in 84 families in the PC-associated keratin genes, comprising 46 distinct keratin mutations. Fourteen were previously unreported mutations, bringing the total number of different keratin mutations associated with PC to 105. CONCLUSIONS: By identifying mutations in KRT6A, KRT6B, KRT6C, KRT16 or KRT17, this study has confirmed, at the molecular level, the clinical diagnosis of PC in these families

    Particle swarm optimization on threshold exponential gain of stimulated Brillouin scattering in single mode fibers.

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    We implement a particle swarm optimization (PSO) algorithm to characterize stimulated Brillouin scattering phenomena in optical fibers. The explicit and strong dependence of the threshold exponential gain on the numerical aperture, the pump laser wavelength and the optical loss coefficient are presented. The proposed PSO model is also evaluated with the localized, nonfluctuating source model and the distributed (non-localized) fluctuating source model. Using our model, for fiber lengths from 1 km to 29 km, the calculated threshold exponential gain of stimulated Brillouin scattering is gradually decreased from 17.4 to 14.6 respectively. The theoretical results of Brillouin threshold power predicted by the proposed PSO model show a good agreement with the experimental results for different fiber lengths from 1 km to 12 km

    Population history from the Neolithic to present on the Mediterranean island of Sardinia: an ancient DNA perspective

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    Recent ancient DNA studies of western Eurasia have revealed a dynamic history of admixture, with evidence for major migrations during the Neolithic and Bronze Age. The population of the Mediterranean island of Sardinia has been notable in these studies –} Neolithic individuals from mainland Europe cluster more closely with Sardinian individuals than with all other present-day Europeans. The current model to explain this result is that Sardinia received an initial influx of Neolithic ancestry and then remained relatively isolated from expansions in the later Neolithic and Bronze Age that took place in continental Europe. To test this model, we generated genome-wide capture data (approximately 1.2 million variants) for 43 ancient Sardinian individuals spanning the Neolithic through the Bronze Age, including individuals from Sardinia{’}s Nuragic culture, which is known for the construction of numerous large stone towers throughout the island. We analyze these new samples in the context of previously generated genome-wide ancient DNA data from 972 ancient individuals across western Eurasia and whole-genome sequence data from approximately 1,500 modern individuals from Sardinia. The ancient Sardinian individuals show a strong affinity to western Mediterranean Neolithic populations and we infer a high degree of genetic continuity on the island from the Neolithic (around fifth millennium BCE) through the Nuragic period (second millennium BCE). In particular, during the Bronze Age in Sardinia, we do not find significant levels of the {“}Steppe{” ancestry that was spreading in many other parts of Europe at that time. We also characterize subsequent genetic influx between the Nuragic period and the present. We detect novel, modest signals of admixture between 1,000 BCE and present-day, from ancestry sources in the eastern and northern Mediterranean. Within Sardinia, we confirm that populations from the more geographically isolated mountainous provinces have experienced elevated levels of genetic drift and that northern and southwestern regions of the island received more gene flow from outside Sardinia. Overall, our genetic analysis sheds new light on the origin of Neolithic settlement on Sardinia, reinforces models of genetic continuity on the island, and provides enhanced power to detect post-Bronze-Age gene flow. Together, these findings offer a refined demographic model for future medical genetic studies in Sardinia

    Dramatic outcomes in epilepsy: depression, suicide, injuries, and mortality

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    In this narrative review, we will discuss some of the significant risks and dramatic consequences that are associated with epilepsy: depression, suicide, seizure-related injuries, and mortality, both in adults and in children. Considering the high prevalence of depression among people with epilepsy (PWE), routine and periodic screening of all PWE for early detection and appropriate management of depression is recommended. PWE should be screened for suicidal ideation regularly and when needed, patients should be referred for a psychiatric evaluation and treatment. When starting an antiepileptic drug (AED) or switching from one to another AED, patients should be advised to report to their treating physician any change in their mood and existence of suicidal ideation. The risk of injuries for the general epilepsy population is increased only moderately. The risk is higher in selected populations attending epilepsy clinics and referral centers. This being said, there are PWE that may suffer frequent, severe, and sometimes even life-threatening seizure-related injuries. The most obvious way to reduce risk is to strive for improved seizure control. Finally, PWE have a 2–3 times higher mortality rate than the general population. Deaths in PWE may relate to the underlying cause of epilepsy, to seizures (including sudden unexpected death in epilepsy [SUDEP] and seizure related injuries) and to status epilepticus, as well as to other conditions that do not appear directly related to epilepsy. Improving seizure control and patient education may be the most important measures to reduce epilepsy related mortality in general and SUDEP in particular

    The impact of herbal infusion consumption on oxidative stress and cancer: The good, the bad, the misunderstood

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    © 2020 by the authors. Licensee MDPI, Basel, Switzerland. The release of reactive oxygen species (ROS) and oxidative stress is associated with the development of many ailments, including cardiovascular diseases, diabetes and cancer. The causal link between oxidative stress and cancer is well established and antioxidants are suggested as a protective mechanism against cancer development. Recently, an increase in the consumption of antioxidant supplements was observed globally. The main sources of these antioxidants include fruits, vegetables, and beverage. Herbal infusions are highly popular beverages consumed daily for different reasons. Studies showed the potent antioxidant effects of plants used in the preparation of some herbal infusions. Such herbal infusions represent an important source of antioxidants and can be used as a dietary protection against cancer. However, uncontrolled consumption of herbal infusions may cause toxicity and reduced antioxidant activity. In this review, eleven widely consumed herbal infusions were evaluated for their antioxidant capacities, anticancer potential and possible toxicity. These herbal infusions are highly popular and consumed as daily drinks in different countries. Studies discussed in this review will provide a solid ground for researchers to have better understanding of the use of herbal infusions to reduce oxidative stress and as protective supplements against cancer development
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