Effects of a blend of garlic oil, nitrate and fumarate on in vitro ruminal fermentation and microbial population.

Although garlic oil and nitrate can effectively suppress ruminal methane (CH4 ) production in vitro, the application of these compounds is associated with suppressed total volatile fatty acid (VFA) concentration. On the other hand, the effectiveness of fumarate as a ruminal CH4 mitigating agent is variable but its application increases total VFA concentration. We therefore hypothesized that the different characteristics of the compounds can compensate for the shortcomings of the other. The objective of this study was to develop an optimal blend of garlic oil, nitrate and fumarate that can suppress in vitro ruminal CH4 without affecting total VFA concentration. Three ruminal in vitro fermentation experiments were carried out. The first one, a one factor at a time experiment was employed to investigate the effective concentration of each of the compounds on CH4 and VFA production by ruminal bacteria. We then applied the fractional factorial design and response surface methodology in the second experiment to determine optimal concentrations of the compounds in the blend. The optimal blending of garlic oil, fumarate and nitrate was determined to be 50 mg/l, 15 mm and 20 mm, respectively. This simulated optimal blend was verified in a 48 h in vitro batch fermentation experiment. The blend achieved the intended goal of suppressing CH4 whilst maintaining total VFA concentration. The blend and nitrate suppressed archaea populations (p < 0.001) but did not affect the total microbial population (p = 0.945). The observed results could be explained by additive effects of the agents making up the blend. Supplementing a high concentrate diet with the blend can significantly decrease ruminal CH4 and maintain total VFAin vitro. These findings however, need to be verified in vivo using the optimized ratio of combining the three methane inhibitors as a guide.

Ultrafast response sensor to formaldehyde gas based on metal oxide.

Thick film semiconductor gas sensors based on indium oxide were fabricated on Si substrate. The sensing materials on Si substrate were characterized using optical microscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM), and so on. They were very fine and uniform and we found out that particle sizes were about 20~30 nm through XRD analysis. Gas responses of fabricated sensors were measured in a chamber where gas flow was controlled by mass flow controller (MFC). Their resistance changes were monitored in real time by using data acquisition board and personal computer. Gas response characteristics were examined for formaldehyde (HCHO) gas which was known as the cause of sick building syndrome. Particularly, the sensors showed responses to formaldehyde gas at sub ppm (cf, standard of natural environment in building is about 80 ppb by ministry of environment in Korea), as a function of operating temperatures and gas concentrations. Also, we investigated sensitivity, repetition, selectivity, response speed and reproducibility of the sensors. The lowest detection limit is HCHO 25 ppb and sensitivity at 800 ppb is over 25% at 350 °C operating temperature. The response time (8 s) and recovery time (15 s) to HCHO gas at 200 ppb were very fast compared to other commercial products in flow type measurement condition. Repetition measurement was very good with ±3% in full measurement range. The fabricated metal oxide gas sensor showed good performance to HCHO gas and proved that it could be adaptable to indoor environment in building.

Low-power-Consumption metal oxide NO2 gas sensor based on micro-heater and screen printing technology.

An NO2 micro gas sensor was fabricated based on a micro-heater using tin oxide nano-powders for effective gas detection and monitoring system with low power consumption and high sensitivity. The processes of the fabrication were acceptable to the conventional CMOS processes for mass-production. Semiconducting SnO2 nano-powders were synthesized via the co-precipitation method; and to increase the sensitivity of the NO2 gas rare metal dopants were added. In the structure of the micro-heater, the resistances of two semi-circular Pt heaters were connected to the spreader for thermal uniformity. The resistance of each heater becomes an electrically equal Wheatstone-bridge, which was divided in half by the heat spreading structure. Based on the aforementioned design, a low-power-consumption micro-heater was fabricated using the CMOS-compatible MEMS processes. A bridge-type micro-heater based on the Si substrate was fabricated via surface micro-machining. The NO2 sensing properties of a screen-printed tin oxide thick film device were measured The micro gas sensors showed substantial sensitivity down to 0.5 ppm NO2 at a low power consumption (34.2 mW).

Low power consumption and high sensitivity carbon monoxide gas sensor using indium oxide nanowire.

In this paper, micro gas sensor was fabricated using indium oxide nanowire for effective gas detection and monitoring system. Indium oxide nanowire was grown using thermal CVD, and their structural properties were examined by the SEM, XRD and TEM. The electric properties for microdropped indium oxide nanowire device were measured, and gas response characteristics were examined for CO gas. Sensors showed high sensitivity and stability for CO gas. And with below 20 mw power consumption, 5 ppm CO could be detected.

Utilization of oil by-product from the purification process of conjugated linoleic Acid as feeding supplements for the accumulation of conjugated linoleic acid in the egg yolk.

This study was performed to examine an efficient way to use oil by-product which is obtained during the purification process of conjugated linoleic acid (CLA) from safflower oil. The CLA by-product (CBP) was fed to the laying hens to accumulate CLA in the egg yolk. Egg yolk samples from 3 different dietary groups were analyzed: control; CBP, 2%; and CLA-80 (which contained 80% free form of CLA), 2%. Fatty acids from the yolk were analyzed by gas chromatography, and the parameters of egg quality were determined. During the feeding trial, there was little alteration in the egg quality and egg production of the tested groups. The CLA contents in the test group with CBP, which contain CLA as glyceride form, significantly increased in the first week of feeding and had the highest level among the tested groups throughout the feeding trials, whereas the CLA group showed an increase in CLA contents from the third week. Moreover, the contents of total CLA isomers in CLA-80 and CBP oils were decreased by 12.92 and 0.51% after heat treatment in 48 h, and the contents of linoleic acid (LA) isomer in LA-80 (which contained 80% free form of LA) and LA by-product (LBP) oils were decreased by 19.63 and 5.78%, respectively. It was confirmed that a major form of fats in CBP was mainly esterified forms, whereas the fats in CLA-80 and LA-80 were composed of free fatty acids. There was no significant difference in the egg quality and production among the tested groups. It is meaningful that the oil by-product could be utilized as a source for functional foods of animal origin without influencing egg quality and production.