251 research outputs found

    New chemical constituent from the rhizomes of Johannesteijsmannia altifrons

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    A new compound namely 2-[(1′E)-3′-hydroxyl-1′-methyl-1′-propen-1′-yl]-6-methoxy-7-[(2′′-methylheptyl)oxy]-5-benzofurancarboxylic acid and three known compounds of β-sitosterol, γ-taraxasterol and stigmasterol were isolated from the n-hexane extracts of the rhizomes and fruits of Johannesteijsmannia altifrons using vacuum liquid, column and radial chromatography. The structures of the isolated compounds were determined by means of 1D and 2D NMR, FT-IR, UV-VIS spectroscopy and mass spectrometry

    GPS Signal Strength Due to Ionospheric Scintillation: Preliminary Models Over Sarawak

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    The renowned effect of space weather is fluctuation in the amplitude of the radio signal that propagates in the ionosphere especially in the equatorial region. This fluctuation is also referred to as scintillation that will intense, degrades the signal quality, reduce the information content, or cause failure of the signal reception. Space-based radio navigation systems such as the Global Positioning System (GPS) will provide us with a unique opportunity to characterize the ionospheric scintillation effect as the signals propagate from the satellites to the GPS receiver. Sarawak, which is located near to the equatorial region, has been selected for the aim of this research. By using amplitude scintillation data recorded by the GPS Ionospheric Scintillation & TEC Monitor (GISTM), ionospheric irregularities along the path was examined and related to the signal strength performance. Methods and procedures to study and analyze the amplitude scintillation data are presented. Furthermore, the amplitude scintillation parameter is related to signal-to-noise ratio (SNR) in order to model the GPS satellite signal strength in this region. The preliminary developed SNR empirical models are a function of amplitude scintillation from the reference station path to the satellites. These contribute to the knowledge of received satellite signals strength performance in terms of ionospheric amplitude scintillation

    Experimental evaluation of fish feeder machine controller system

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    The aim of this project is to apply the automatic fish feeder controller system for fish pellet dispersion machine. The system uses Arduino as a microcontroller which programmed by setting the speed and timer of each DC motor to make this machine functioning automatically. When the adapter is switch, the microcontroller will be connected then activate the motor driver to generate the system. Two motors have been used as motor 1 and motor 2 which functions to drop and disperse the fish pellet respectively. The whole system was programmed through a specific coding and uploaded to the Arduino. This project benefits in reduce the manpower for the fish farming. The component that required to build this project is portable and cost-effective. From experimental result, the timer for motor 1 to dispense the fish food from the storage was 60s while 90s for DC motor 2 as a distributor. The speed for motor 1 was set to 110rpm while motor 2 was set with full speed of 255rpm. The fish pellet can be distributed and scattered up to 5m which can reduce the competition among the fish at one place

    Blood coagulation and beyond:Position paper from the Fourth Maastricht Consensus Conference on Thrombosis

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    The 4th Maastricht Consensus Conference on Thrombosis (MCCT), included the following themes: Theme 1: The coagulome as a critical driver of cardiovascular disease Blood coagulation proteins also play divergent roles in biology and pathophysiology, related to specific organs, including brain, heart, bone marrow and kidney. Four investigators shared their views on these organ-specific topics. Theme 2: Novel mechanisms of thrombosis Mechanisms linking factor XII to fibrin, including their structural and physical properties, contribute to thrombosis, which is also affected by variation in microbiome status. Virus infections associated-coagulopathies perturb the hemostatic balance resulting in thrombosis and/or bleeding. Theme 3: How to limit bleeding risks: insights from translational studies This theme included state of the art methodology for exploring the contribution of genetic determinants of a bleeding diathesis; determination of polymorphisms in genes that control the rate of metabolism by the liver of P2Y12 inhibitors, to improve safety of antithrombotic therapy. Novel reversal agents for direct oral anticoagulants are discussed. Theme 4: Hemostasis in extracorporeal systems: how to utilize ex vivo models? Perfusion flow chamber and nanotechnology developments are developed for studying bleeding and thrombosis tendencies. Vascularised organoids are utilized for disease modeling and drug development studies. Strategies for tackling extracorporeal membrane oxygenation (ECMO) associated coagulopathy are discussed. Theme 5: Clinical dilemmas in thrombosis and antithrombotic management Plenary presentations addressed controversial areas, ie thrombophilia testing, thrombosis risk assessment in hemophilia, novel antiplatelet strategies and clinically tested factor XI(a) inhibitors,both possibly with reduced bleeding risk. Finally, Covid-19 associated coagulopathy is revisited.</p

    Search for leptophobic Z ' bosons decaying into four-lepton final states in proton-proton collisions at root s=8 TeV

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    Search for black holes and other new phenomena in high-multiplicity final states in proton-proton collisions at root s=13 TeV

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    Measurements of differential production cross sections for a Z boson in association with jets in pp collisions at root s=8 TeV

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    Search for high-mass diphoton resonances in proton-proton collisions at 13 TeV and combination with 8 TeV search

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