1,604 research outputs found
Evaluation Of The Essential Oil Of Foeniculum Vulgare Mill (Fennel) Fruits Extracted By Three Different Extraction Methods By Gc/Ms
Background: Hydrodistillation (HD) and steam-distillation, or solvent extraction methods of essential oils have some disadvantages like thermal decomposition of extracts, its contamination with solvent or solvent residues and the pollution of residual vegetal material with solvent which can be also an environmental problem. Thus, new green techniques, such as supercritical fluid extraction and microwave assisted techniques, are potential solutions to overcome these disadvantages.Materials and Methods: The aim of this study was to evaluate the essential oil of Foeniculum vulgare subsp. Piperitum fruits extracted by three different extraction methods viz. Supercritical fluid extraction (SFE) using CO2, microwave-assisted extraction (MAE) and hydro-distillation (HD) using gas chromatography-mass spectrometry (GC/MS).Results: The results revealed that both MAE and SFE enhanced the extraction efficiency of the interested components. MAE gave the highest yield of oil as well as higher percentage of Fenchone (28%), whereas SFE gave the highest percentage of anethol (72%).Conclusion: Microwave-assisted extraction (MAE) and supercritical fluid extraction (SFE) not only enhanced the essential oil extraction but also saved time, reduced the solvents use and produced, ecologically, green technologies.Keywords: Foeniculum vulgare subsp. Piperitum, microwave-assisted extraction (MAE), Supercritical fluid extraction (SFE), Essential Oils,Anethol, Fenchone, Limonene, Pinene, GC/MS
Generalised and Versatile Connected Health Solution on the Zynq SoC
This chapter presents a generalized and versatile connected health solution for patient monitoring. It consists of a mobile system that can be used at home, an ambulance and a hospital. The system uses the Shimmer sensor device to collect three axes (x, y and z) accelerometer data as well as electrocardiogram signals. The accelerometer data is used to implement a fall detection system using the k-Nearest Neighbors classifier. The classification algorithm is implemented on various platform including a PC and the Zynq system on chip platform where both programmable logic and processing system of the Zynq are explored. In addition, the electrocardiogram signals are used to extract vital information, the signals are also encrypted using the Advanced Encryption Standard and sent wirelessly using Wi-Fi for further processing. Implementation results have shown that the best overall accuracy reaches 90% for the fall detection while meeting real-time performances when implemented on the Zynq and while using only 48% of Look-up Tables and 22% of Flip-Flops available on chip
Acute Toxicity Study and Hepatocurative Effect of Aqueous Stem Bark Extract of Parkia Biglobosa in Wister albino Rats
Parkia biglobosa plant is widely is used in folk medicinal practices to treat and/or manage various diseases including diabetes, malaria, diarrhea and pains. The current research seek to establish the toxicity profile and hepatocurative ability of aqueous stem bark extract of the plant. Twelve (12) rats were used for Oral LD50 determination, and were grouped into four (4) groups of three rats (3) each. The first three groups were administered with 10 mg/kg, 100 mg/kg and 1000 mg/kg body weight of the extract respectively, while the last group was subdivided into three groups of one rat each and were administered with 2500mg/kg, 3500mg/kg and 5000mg/kg body weight of the extract respectively. For the hepatocurative studies, twenty five (25) experimental rats were divided into five groups of five (5) rats each. Group I served as normal rats, Group II served as test Control while Groups III to V were induced with liver damage and administered with 50mg/kg, 100mg/kg and 150mg/kg of the extract respectively. The LD50 was found to be greater than 5000mg/kg, while phytochemical screening revealed the presence of Flavanoids, Glycosides, Tanins, Saponins, Steroids and Phenols, with the absence of Anthraquinones. For the hepatocurative study, a significant (p<0.0.5) increase in serum albumin and liver enzymes (AST, ALT and ALP) was observed in test control compared to normal control. Upon administration of the extract, a significant (p<0.0.5) fall in Albumin, AST, ALT and ALP was recorded in a dose dependent pattern. No significant difference (p>0.05) was observed between groups in total protein, direct and total bilirubin. The research concludes that the extract is practically non-toxic and possess strong hepatocurative ability which might be due to the phytochemicals present. Keywords: Acute toxiicity; CCl4; Liver; P. biglobosa; Phytochemical and wistar rats. DOI: 10.7176/JNSR/13-16-04 Publication date:September 30th 202
The relationship between daily maximum temperature and daily maximum ground level ozone concentration
Ground-level ozone is one of the dominant criteria pollutants that contribute to unhealthy days in ambient air measurements throughout Malaysia. In addition to VOCs and NOx, meteorological factors such as insolation and temperature influence the formation of ground-level ozone. For this reason, the relationship between daily maximum temperature and variation of ground-level ozone concentrations using 10 years of data (2000-10, excluding 2008) was scrutinized statistically at two stations representing urban and industrial areas in Terengganu State, Malaysia. We found that there is a positive linear correlation between maximum daily temperature and maximum daily ozone concentration with correlation coefficients of 0.684 and 0.605 for urban and industrial areas, respectively. Nevertheless, the long-term variation of daily maximum temperature and daily maximum ozone concentration for these two stations shows that the levels were higher in the industrial rather than the urban area. The results indicate that surrounding activities and temperature play vital roles in influencing ground-level ozone concentrations in Terengganu. Furthermore, ozone concentrations are highest for air masses characterized by dry, warm conditions during the southwest monsoon and are usually associated with the generation of haze episodes in the Malaysian Peninsula
Relaxation bottleneck and its suppression in semiconductor microcavities
A polariton relaxation bottleneck is observed in angle-resolved measurements of photoluminescence emission from a semiconductor microcavity. For low power laser excitation, low k polariton states are found to have a very small population relative to those at high k. The bottleneck is found to be strongly suppressed at higher powers in the regime of superlinear emission of the lower polariton states. Evidence for the important role of carrier-carrier scattering in suppression of the bottleneck is presented
Continuous wave observation of massive polariton redistribution by stimulated scattering in semiconductor microcavities
A massive redistribution of the polariton occupancy to two specific wave vectors is observed under conditions of continuous wave excitation of a semiconductor microcavity.
The “condensation” of the polaritons to the two specific states arises from stimulated scattering at final
state occupancies of order unity. The stimulation phenomena, arising due to the bosonic character of
the polariton quasiparticles, occur for conditions of resonant excitation of the lower polariton branch.
High energy nonresonant excitation, as in most previous work, instead leads to conventional lasing in
the vertical cavity structure
Development and characterisation of novel electrospun polylactic acid/tubular clay nanocomposites
A novel material formulation method of polylactic acid /tubular clay nanocomposites via electrospinning was introduced and the important processing parameters such as solution concentration, clay loading, material feed rate were particularly investigated. The hybrid fibre diameter, the clay dispersability and the thermal properties of such nanocomposites were then characterised by using the scanning electron microscopy, wide-angle X-ray diffraction and differential scanning calorimetry, respectively, to establish a fundamental structure–property relationship for the future application
Transition probabilities for general birth-death processes with applications in ecology, genetics, and evolution
A birth-death process is a continuous-time Markov chain that counts the
number of particles in a system over time. In the general process with
current particles, a new particle is born with instantaneous rate
and a particle dies with instantaneous rate . Currently no robust and
efficient method exists to evaluate the finite-time transition probabilities in
a general birth-death process with arbitrary birth and death rates. In this
paper, we first revisit the theory of continued fractions to obtain expressions
for the Laplace transforms of these transition probabilities and make explicit
an important derivation connecting transition probabilities and continued
fractions. We then develop an efficient algorithm for computing these
probabilities that analyzes the error associated with approximations in the
method. We demonstrate that this error-controlled method agrees with known
solutions and outperforms previous approaches to computing these probabilities.
Finally, we apply our novel method to several important problems in ecology,
evolution, and genetics
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