Comparison of Essential Oil of Lemongrass (Cymbopogon Citratus) Extracted with Microwave-Assisted Hydrodistillation (MAHD) and Conventional Hydrodistillation (HD) Method

The increasing demand of essential oil has opened up wide opportunities for global marketing which leads to the requirement of its competitive product in market that comes with all the advantages in term of cost, quality and its production time. Microwave-assisted hydrodistillation (MAHD) method is an advance extraction technique that takes advantage of microwave heating with the conventional hydrodistillation (HD). This research was carried out to study the effect of different MAHD parameters which were water to plant material ratio (6:1, 8:1,10:1), microwave power (200 W,250W) and extraction time (30min,60min, 90min,120min) in extraction of essential oil from Lemongrass (Cymbopogon Citratus). Its extraction yield and major constituents were analyzed and the results were compared with those of conventional HD. The optimum parameters were found at water to plant material ratio of 8:1, microwave power of 250W and 90 minutes of extraction and the yield obtained under this condition was 1.46%. The gas chromatography/mass spectrometric (GC-MS) analysis showed that the content of main constituents which were neral, geranial and myrcene were almost similar in the essential oil extracted using MAHD and conventional HD. This has proved that the use of microwave irradiation did not adversely influence the composition of essential oils. Overall, the results obtained indicate that MAHD method provided a good alternative for the extraction of essential oil from Lemongrass (Cymbopogon Citratus)

Gonadotropin releasing hormone in first trimester human placenta: isolation, partial characterisation and in vitro biosynthesis

Using a specific radioimmunoassay for gonadotropin releasing hormone, the presence of gonadotropin releasing hormone like material in the first trimester human placenta has been demonstrated. The material has been partially characterized using carboxy methyl cellulose chromatography, high pressure gel permeation chromatography and reverse phase C18 high pressure liquid chromatographic analysis. Analysis for bioactivity revealed that placental gonadotropin releasing hormone is much more active than synthetic gonadotropin releasing hormone in in vitro rat pituitary lutinising hormone release assay. In vitro biosynthetic studies using labelled precursors and immunoaffinity chromatography indicated that first trimester human placenta synthesizes gonadotropin releasing hormone like material

Identification of Glycochenodeoxycholate 3-O-glucuronide and Glycodeoxycholate 3-O-glucuronide as Highly Sensitive and Specific OATP1B1 Biomarkers

The aim of this study was to investigate the sensitivity and specificity of endogenous glycochenodeoxycholate and glycodeoxycholate 3-O-glucuronides (GCDCA-3G and GDCA-3G) as substrates for organic anion transporting polypeptide 1B1 (OATP1B1) in humans. We measured fasting levels of plasma GCDCA-3G and GDCA-3G using liquid chromatography-tandem mass spectrometry in 356 healthy volunteers. The mean plasma levels of both compounds were similar to 50% lower in women than in men (P = 2.25 x 10(-18) and P = 4.73 x 10(-9)). In a microarray-based genome-wide association study, theSLCO1B1rs4149056 (c.521T>C, p.Val174Ala) variation showed the strongest association with the plasma GCDCA-3G (P = 3.09 x 10(-30)) and GDCA-3G (P = 1.60 x 10(-17)) concentrations. The mean plasma concentration of GCDCA-3G was 9.2-fold (P = 8.77 x 10(-31)) and that of GDCA-3G was 6.4-fold (P = 2.45x10(-13)) higher in individuals with theSLCO1B1c.521C/C genotype than in those with the c.521T/T genotype. No other variants showed independent genome-wide significant associations with GCDCA-3G or GDCA-3G. GCDCA-3G was highly efficacious in detecting theSLCO1B1c.521C/C genotype with an area under the receiver operating characteristic curve of 0.996 (P <0.0001). The sensitivity (98-99%) and specificity (100%) peaked at a cutoff value of 180 ng/mL for men and 90 ng/mL for women. In a haplotype-based analysis,SLCO1B1*5and*15were associated with reduced, andSLCO1B1*1B, *14, and *35with increased OATP1B1 function.In vitro, both GCDCA-3G and GDCA-3G showed at least 6 times higher uptake by OATP1B1 than OATP1B3 or OATP2B1. These data indicate that the hepatic uptake of GCDCA-3G and GDCA-3G is predominantly mediated by OATP1B1. GCDCA-3G, in particular, is a highly sensitive and specific OATP1B1 biomarker in humans.Peer reviewe

Two-dimensional Co-directed metal-organic networks featuring strong antiferromagnetism and perpendicular anisotropy

Antiferromagnetic spintronics is a rapidly emerging field with the potential to revolutionize the way we store and process information. One of the key challenges in this field is the development of novel two-dimensional antiferromagnetic materials. In this paper, we report the first on-surface synthesis of a Co-directed metal-organic network in which the Co atoms are strongly antiferromagnetically coupled, while featuring a perpendicular magnetic anisotropy. This material is a promising candidate for future antiferromagnetic spintronic devices, as it combines the advantages of twodimensionality and metal-organic chemistry with strong antiferromagnetic order and perpendicular magnetic anisotropy.Peer reviewe

A Comparative Study of Lemongrass (Cymbopogon Citratus) Essential Oil Extracted by Microwave-Assisted Hydrodistillation (MAHD) and Conventional Hydrodistillation (HD) Method

The demand of essential oil in current industry has increased due to its bioactive compound that shows various therapeutic effects. Microwave-assisted hydrodistillation (MAHD) is an advanced hydrodistillation (HD) technique, in which a microwave oven is used as the heating source. MAHD extraction of essential oil from Lemongrass (Cymbopogon Citratus) was studied. The effect of different parameters, such as water to plant material ratio (6:1, 8:1,10:1), microwave power (200 W,250W) and extraction time (30min,60min, 90min,120min) on the extraction yield and its major constituents were investigated and the results were compared with those of conventional HD. These essential oils were further analyzed by gas chromatography/mass spectrometric (GC-MS) to evaluate the effect of extraction method on the content of its main constituents which were neral, geranial and myrcene and some minor compounds such as linalool, geranic acid and citronellol. The optimum parameters were found at water to plant material ratio of 8:1, microwave power of 250W and 90 minutes of extraction and the yield obtained under this condition was 1.46%. GC-MS analysis has proved that the use of microwave irradiation did not adversely influence the composition of essential oils as the main constituents found through both methods were almost similar in term of quality and quantity. The results obtained indicate that MAHD method provided a good alternative for the extraction of essential oil from Lemongrass (Cymbopogon Citratus

Återvinning av motorvärme i lastbilsmotorergenom att kombinera ett evaporativt motorkylningssystemmed en Rankine-cykel.

Engine Cooling losses constitutes about 20% of the injected fuel energy in a modern heavy duty truck diesel engine. The objective of this Master Thesis Project is to investigate flow boiling cooling as a thermally efficient method for waste heat recovery as well as a good solution for precision cooling. First, an engine heat transfer model was implemented on GT-suite software in order to estimate heat fluxes within the engine cylinder. Liners being less thermally constrained than the cylinder head, flow boiling cooling was then investigated in the liner’s water jackets. A more adapted heat transfer model taking into account both gas side and cooling side of the liner was thus implemented on Simulink. Unlike commercials software, this simple model allowed to implement the relevant two-phase heat transfer correlations and to study in details the boiling flow behaviors. The hydraulic diameter of the water jackets, the fluid saturated pressure and the surface area of heat transfer are the major parameters and they were studied for various mass flow rate in order to analyze how they influence wall temperature and heat transfer. This study showed good operating conditions for very low mass flow rate (about 1% of the typical mass flow rate for liquid convective cooling). Due to flow control issues, it implied the consideration of other fluids such as refrigerants but showed good prospect for cooling system simplification. This flow boiling model was finally inserted in a complete Rankine loop model using water as a working fluid to study potential efficiency improvements. A Rankine loop using water as a working fluid would thus improve the heat recovery of the considered engine of about 4.8% of the net engine brake power, recovering heat from the liners and the exhaust gases at 1800RPM, full load. Further simulations have also been led with R245fa, which shows a WHR of about 5.5% of the net engine brake power at 1800RPM, full load.Motorns kylförluster utgör ca 20 % av energin som injiceras i dieselmotorn på en modern lastbil. Målet med detta examensarbete är att undersöka om flödes kokande kylning är en termiskt effektiv metod för att återvinna spillvärmes och en effektiv lösning för precisionskyla. Först genomfördes en motorvärmeöverföringsmodell på GT-suite för att beräkna värmeflöden i motorcylindern. Eftersom cylinderfoder är mindre termiskt begränsade än topplockundersöktes flödes kokande kylning i cylinderfoder. En mer anpassad värmeöverföringsmodell med hänsyn till både avgas- och kylmedelsidan på cylinderfoder genomfördes således med Simulink. Till skillnad från kommersiella programvaror, gör denna enkla modell det möjligt att utföra 2-fas värmeöverföringskorrelationer och studera flödes kokande beteendet i detalj. De viktigaste parametrarna (vattenmantelns hydrauliska diameter, vätsketrycket och ytan av värmeöverföringarna) studerades för olika massflöden för att analysera hur de påverkar väggtemperatur och värmeöverföring. Undersökningen visade goda arbetsförhållanden för mycket låga massflöden (ca 1 % av det typiska massflödet för konvektiv vätskekylning). På grund av problem med flödesregleringen, behövde andra vätskor beaktas som köldmedier men hade god potential för att kyla systemet effektivt. För att studera potentiella förbättringar av energieffektiviteten infördes den flödes kokande modellen slutligen i en komplett modell av en Rankine-krets där vatten användes som kylmedel. En Rankine-krets med vatten skulle förbättra värmeåtervinningen på den avsedda motorn med 4,8 % motorns bromskraft, genom att återvinna värme från cylinderfoder och avgaserna vid 1800 RPM, full belastning. Ytterligare simulationer har också hållits med R245fa, som visar en återvinning av spillvärmen med 5,5 % av motorns bromskraft vid 1800 RPM, full belastning