The efficacy of docosahexaenoic acid (DHA) in suppressing eicosanoic synthesis by peritoneal macrophagesin vivo was influenced by the relative amount of dietary DHA when linoleic acid (LA) was held constant. Increasing DHA from 0 to
37% of the fatty acids in diets containing 10 weight % fat (of which LA was 40%) caused an eleven-fold increase in the DHA
content of macrophages. Limited retroconversion of DHA to eicosapentaenoic acid was observed. Macrophages in animals consuming
DHA synthesized significantly lower amounts of leukotriene E4, prostaglandin E2 and 6-keto prostaglandin F1αin vivo upon stimulation with zymosan. The maximum inhibition of eicosanoid synthesis was observed when the dietary DHA/LA ratio
was 0.16 and no further inhibition occurred when the ratio was increased up to 0.81. 相似文献
In this research, a new speech recognition method based on improved feature extraction and improved support vector machine (ISVM) is developed. A Gaussian filter is used to denoise the input speech signal. The feature extraction method extracts five features such as peak values, Mel frequency cepstral coefficient (MFCC), tri-spectral features, discrete wavelet transform (DWT), and the difference values between the input and the standard signal. Next, these features are scaled using linear identical scaling (LIS) method with the same scaling method and the same scaling factors for each set of features in both training and testing phases. Following this, to accomplish the training process, an ISVM is developed with best fitness validation. The ISVM consists of two stages: (i) linear dual classifier that finds the same class attributes and different class attributes simultaneously and (ii) cross fitness validation (CFV) method to prevent over fitting problem. The proposed speech recognition method offers 98.2% accuracy. 相似文献
Response surface methodology is a statistical design that helps one to determine optimal conditions for an enzyme-catalyzed
reaction by performing a minimal number of experiments. This methodology was adapted for modifying coconut oil TAG by using
lipase-catalyzed acidolysis in hexane to incorporate n−3 or n−6 PUFA. FFA obtained after hydrolysis of cod liver oil and safflower
oil were used as acyl donors. Immobilized lipase, Lipozyme IM60, from Rhizomucor miehei was used for catalyzing the reaction. The reaction conditions—substrate molar ratio, incubation time, and temperature—were
optimized. The experimental data were fitted to a response function based on the central composite rotatable design. The optimal
conditions generated from models indicated that maximal incorporation of n−3 PUFA occurred at a 1∶4 molar ratio of TAG/FFA
when incubation was carried out for 34 h at 54°C. Similarly, maximal incorporation of n−6 FA was predicted at a 1∶3 molar
ratio of TAG/FFA when incubated for 48.5 h at 39°C. Experiments conducted at optimized conditions predicted by the equation
obtained from response surface methodology yielded structured lipids with 13.65 and 45.5% of n−3 and n−6 FA, respectively.
These values agreed well with that predicted by the model. The reactions were also scaled up to 100 g levels in batch reactors
with the incorporation level of n−3 and n−6 fatty acids agreeing closely with that observed when the reactions were carried
out at lab scale (100 mg). These studies indicated that response surface methodology is a useful tool in predicting the conditions
for incorporating desired levels of specific FA during the synthesis of structured lipids. 相似文献
Three groups of male mice were fed a normal diet or a semisynthetic diet containing either 10% hydrogenated coconut oil (CO
group) or 10% menhaden oil (MO group) for two wk. The synthetic diet altered the fatty acid composition of lung microsomal
lipids. Mice ingesting menhaden oil contained greater amounts of eicosapentaenoic acid (20∶5 n−3), docosapentaenoic acid (22∶5
n−3) and docosahexaenoic acids (22∶6 n−3) and decreased amounts of n−6 fatty acids such as arachidonic and adrenic. Synthesis
of prostaglandin E2 and prostaglandin F2α from exogenous arachidonic acid was significantly depressed in n−3 fatty acid-enriched lung microsomes. These studies indicated
that dietary fish oil not only alters the fatty acid composition of lung microsomes but also lowers the capacity of lungs
to synthesize prostaglandins from arachidonic acid. 相似文献
Planar antenna with a specific resonant mode is essential to meet the diversity demand for wireless communication. This paper presents modeling and experimental validation of a microstrip antenna design in which multiple resonant frequencies are excited based on different negative permeability response of the rectangular split ring resonator (SRR). The antenna geometry consists of a slotted patch with split ring resonator loaded between its two arms. The patch was fabricated on FR-substrate of relative permittivity εr?=?4.4, and has a size of 30.5 mm?×?34 mm. In the antenna desing, PIN diodes connect the outer ring and inner ring resonator of the SRR to the adjacent arms of the patch. Under various bias conditions, quad-band resonance was observed at 2.07 GHz, 2.11 GHz, 2.31 GHz, and 2.46 GHz. The measured S11 results are found comparable to the simulated data, and demonstrate proper functioning of the proposed antenna with stable gain and radiation patterns. 相似文献
The safe and efficient storage of hydrogen is widely recognized as one of the key technological challenges in the transition towards a hydrogen-based energy economy. Whereas hydrogen for transportation applications is currently stored using cryogenics or high pressure, there is substantial research and development activity in the use of novel condensed-phase hydride materials. However, the multiple-target criteria accepted as necessary for the successful implementation of such stores have not yet been met by any single material. Ammonia borane, NH3BH3, is one of a number of condensed-phase compounds that have received significant attention because of its reported release of approximately 12 wt% hydrogen at moderate temperatures (approximately 150 degrees C). However, the hydrogen purity suffers from the release of trace quantities of borazine. Here, we report that the related alkali-metal amidoboranes, LiNH2BH3 and NaNH2BH3, release approximately 10.9 wt% and approximately 7.5 wt% hydrogen, respectively, at significantly lower temperatures (approximately 90 degrees C) with no borazine emission. The low-temperature release of a large amount of hydrogen is significant and provides the potential to fulfil many of the principal criteria required for an on-board hydrogen store. 相似文献
Industrially produced partially hydrogenated vegetable fat (PHVF) contains trans fatty acids (TFA) mostly comprising elaidic acid (EA, 18:1?9t). Though, the harmful effects of TFA on health have been repeatedly publicized, the fat containing TFA have been continued to be used as a cooking medium in many regions of the world. The adverse effects of PHVF on oxidative stress and inflammatory markers and the possible ameliorative action of rice bran oil (RBO) on these markers were evaluated. Weaning rats were fed a AIN‐93 purified diet supplemented with the following lipids: groundnut oil (GNO, 10 wt%), PHVF (10 wt%), RBO (10 wt%), PHVF blended with RBO at 2.5, 5.0 and 7.5 wt% levels. The final concentration of the lipids in the diet was maintained at 10 wt%. Rats were fed these diets for 60 days. They were sacrificed and analyzed for oxidative stress and inflammatory markers. The rats fed PHVF showed lower levels of lipid peroxidation and hepatic antioxidant enzymes. The rats fed PHVF‐containing diets showed enhanced levels of interleukin‐1β, C‐reactive proteins and also showed enhanced levels of paw inflammation when injected with carrageenan as compared to rats given GNO, RBO or PHVF blended with incremental amounts of RBO. The macrophages from rats fed diet containing PHVF showed up‐regulation in the expressions of cytosolic phospholipase A2 (cPLA2), nuclear factor‐κB p65, toll like receptor (TLR)‐2, TLR‐4 and down‐regulation in the expressions of peroxisome proliferator activated receptor gamma (PPAR)γ, adiponectin receptor (AdipoR)‐1 and AdipoR‐2 when compared to rats fed diet containing GNO, RBO and PHVF blended with RBO. It was concluded that dietary PHVF enhance pro‐inflammatory markers which can be reduced by judiciously blending PHVF with RBO. 相似文献
Various aspects of in situ formation of Al2O3–SiC composites by the self-propagating high-temperature synthesis (SHS) technique have been investigated using thermal analyses (TG/DTA) of a powder mixture (4Al, 3SiO2, 3C) and pellets in an argon atmosphere at different heating rates. Both the reaction initiation and peak temperatures are found to increase with the heating rates. At lower heating rates, the powder samples do not reveal any exothermic peak possibly because of poor reactivity and sluggish exothermic reaction. The appearance of exothermic peaks in the DTA plots after melting of aluminum indicates reduction of silica by liquid aluminum. Conversion of aluminum is found to decrease marginally with an increase in heating rates. The apparent activation energy of the process compares well with the interdiffusion activation energy of silicon and oxygen, indicating that oxygen diffusion in Si formed at the reaction front may be the rate-controlling factor for this SHS process. From SEM studies it appears that the formation of SiC whiskers is through liquid-phase mass transfer. 相似文献
Algal blooms, the spread of algae on the surface of water bodies, have adverse effects not only on aquatic ecosystems but also on human life. The adverse effects of harmful algal blooms (HABs) necessitate a convenient solution for detection and monitoring. Unmanned aerial vehicles (UAVs) have recently emerged as a tool for algal bloom detection, efficiently providing on-demand images at high spatiotemporal resolutions. This study developed an image processing method for algal bloom area estimation from the aerial images (obtained from the internet) captured using UAVs. As a remote sensing method of HAB detection, analysis, and monitoring, a combination of histogram and texture analyses was used to efficiently estimate the area of HABs. Statistical features like entropy (using the Kullback–Leibler method) were emphasized with the aid of a gray-level co-occurrence matrix. The results showed that the orthogonal images demonstrated fewer errors, and the morphological filter best detected algal blooms in real time, with a precision of 80%. This study provided efficient image processing approaches using on-board UAVs for HAB monitoring.