118 research outputs found
Compact silicon photonics circuit to extract multiple parameters for process control monitoring
We present a compact interferometer circuit to extract multiple model parameters of on-chip waveguides and directional couplers from optical measurements. The compact design greatly improves the accuracy of extraction with fewer measurements, making it useful for process monitoring and detailed wafer-level variability analysis. We discuss the design requirements and illustrate the extraction using the Restart-CMA-ES global optimization algorithm. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreemen
Kinetic Studies of Alkaline Phosphatase from the Liver of Agama agama Lizard
Kinetic studies were carried out on alkaline phosphatase (ALP) extracted from the liver of Agama agama lizard. Incubation of ALP extract with para – nitrophenyl phosphate formed the basis for the determination of enzyme activity. Spectrophotometric method was used to assay the enzyme, and the kinetic constants: Maximum velocity (Vmax) and Michaelis Menten constant (Km) were calculated. The Km and Vmax values were 2.5mM and 1.538 X 10-3 ìmol/min respectively. Inhibition studies show that the enzyme activity was competitively inhibited by 0.67mM sodium hydrogen orthophosphate (NaH2PO4) with inhibition constant (Ki) of 2.27mM. The optimum pH of the enzyme was 9.9 and the optimum temperature was 35OC. The enzyme exhibited linear Arrhenius relationship with corresponding catalytic energy of activation (Ea) of 1.44KJmol-1. This study gives an insight of the catalytic properties of ALP extracted from the liver of Agama agama lizard.Keywords: Alkaline phosphatase, Agama agama, para – nitrophenyl phosphate (p - NPP), Arrhenius relationship, Michaelis Menten constant
Comparative study on the proximate content of the flesh of red and yellow fruits of Terminalia catappa L.
The flesh of two fruits were analysed and compared for their proximate compositions on dry weight basis, the red fruits have the following proximate composition: ash content (7.83±0.76%): crude protein (3.92±0.08%): crude fibre (8.67±0.29%): crude lipid (1.33±0.29%): and available carbohydrate (78.31+ 1.14%) with high energy value (1447.19 KJ per 100g). The moisture content (71.33±6.90) was high. while for the yellow sample are: ash content (8.33 ±0.76%): crude protein (10.01±0.43%): crude fibre (15.83±0.29%): crude lipid (0.67±0.29%): and available carbohydrate (64.90± 0.69%) with high energy value (1295.13 KJ per 100g). The moisture content (84.00± 2.00%): the result showed moisture, crude protein and crude fibre are significantly (p<0.05) higher in yellow compared to red variety. On the other hand crude lipid, available carbohydrate and calorific value were significantly (p<0.05) higher in the red variety. Ash content however, showed no significant (p>0.05) variation between the two varieties.Key words: proximate composition, crude lipid, available carbohydrate, crude protein
Column-row addressing of thermo-optic phase shifters for controlling large silicon photonic circuits
We demonstrate a time-multiplexed row-column addressing scheme to drive thermo-optic phase shifters in a silicon photonic circuit. By integrating a diode in series with the heater, we can connect heaters in an matrix topology to row and column lines. The heaters are digitally driven with pulse-width modulation, and time-multiplexed over different channels. This makes it possible to drive the circuit without digital-to-analog converters, and using only wires. We demonstrate this concept with a power splitter tree with 15 thermo-optic phase shifters that are controlled in a matrix, connected through 8 bond pads. This technique is especially useful in silicon photonic circuits with many tuners but limited space for electrical connections
Prenylation of Aromatic Secondary Metabolites: A New Frontier for Development of Novel Drugs
Prenylation of aromatic secondary metabolites is an important process involved in the biosynthesis of many biologically active compounds in plants and animals. Many prenylated natural products have been shown to exhibit very good anti-tumor, anti inflammatory and antimicrobial activities. The addition of prenyl side chain to an aromatic secondary metabolite often affects its pharmacological activity. The aim of this review is to examine the influence of the prenyl side chain on the pharmacological activities of some classes of aromatic secondary metabolites and the potential application of prenylation in the development of novel drugsKeywords: Secondary metabolite, Prenylation, Aromatic, Ras antagonist, Novel drugs
Study of Bioavailability of Ca and Zn in the Flesh of Yellow Terminalia catappa (Linn) Fruits
The analyses of antinutritional and mineral composition of the flesh of yellow fruits variety of Terminal catappa using standard methods were conducted. The results (mg/100g dry sample) are as follows: Total oxalate 1.90, soluble oxalate 1.62, tannin 16.28, phytate 2872.67, saponin 1.495, nitrate 0.64, hydrocyanic acid 4.19, Ca 143.30, Mg 48.50 and Zn 1.42. Bioavailability studies revealed that the oxalate content of the fruit have no effect on Ca availability as Oxalate]/[Ca] and [Oxalate]/[Ca + Mg] are below critical level of 2.5. However, phytate affect both the Ca and Zn bioavailability with [Phytate]/[Ca] and [Ca][Phytate]/[Zn] above critical level of 0.2 and 0.5 respectively.Keywords: Anti-nutritional, Terminal catappa, fruits, minerals, bioavailability
Checklist and Comparison of Butterfly Species found in Zoological and Botanical Gardens, University of Nigeria, Nsukka, Enugu State, Nigeria
Butterflies are creatures of nature with great economic importance as pollinators and bio-indicators. This study provides checklist of butterfly species present in Zoological and Botanical gardens of University of Nigeria, Nsukka and was conducted for three Months. Butterflies were sampled twice a week between 7.00 -10.00am from May to July 2019; using sweep net along existing transects within the gardens. Non-invasive method was adopted, butterflies were captured, photographed and released. Photographed samples were identified to species level by cross matching with relevant keys. A total of 91 butterflies belonging to 16 species, 10 genera and 3 families were sampled. Alpha diversity test showed a significant difference (p<0.05) in terms of Relative Abundance, Diversity and Dominance of butterfly species between the two gardens. The Botanical garden had Relative Abundance of 63.73%, Dominance of 0.23 which was higher compared to Zoological garden which had 36.16% and 0.10; but these was contrary to species diversity where Zoological garden was more diverse (H1=2.48) than botanical garden (H1=1.82). The differences observed could be attributed to variations in vegetation composition
Tutorial : programmable integrated photonics
Programmable photonic circuits are optical chips whose functionality can be (re)configured through electronics and software. This programmability enables new functionality, and opens the path to general-purpose photonic chips, similar to electronic FPGAs. This tutorial discusses the operational principles and technology stack for these chips
Model Predictive Control of Blood Pressure and Urine Production Rate for a Physiological Patient Model
The research proposes the design of a model predictive control (MPC) for automatic drug dosing to regulate high blood pressure and urine production rate in an elderly patient. Combining hydrochlorothiazide and oxybutynin is commonly used for regulation of blood pressure in elderly patients. The patient’s model tries to captures the responses to the drugs as the blood pressure and urine production rates attains their various set-points. Hence, this research aims at improving the control scheme which ensured that these two physiological variables are regulated. Simulation was done in MATLAB/Simulink environment with the use of MPC Toolbox, and the controlled variables were constrained to operate at 80mmHg for blood pressure and between 24-49 ml/kg/hr for urine production rate respectively while the manipulated variables remained unconstrained. From the simulation results, the MPC controller achieved good set-point tracking and disturbance rejection, which is an indication of a healthy level of regulation within acceptable tolerances
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