Evaluation of the Chemical Composition and Antioxidant Activity of the Peel Oil of Citrus nobilis

Peel oil of Citrus nobilis (Lour) was analyzed for determining its chemical composition. Fourteen identified components accounted for 99.1% (GC) and 100.0% (FID) of the total oil. Major component of the oil was limonene (76.8%-GC and 86.2%-FID). Essential oil was also evaluated for its antioxidant activity in four complementary test systems namely; β-carotene/linoleic acid, DPPH radical scavenging, reducing power and metal chelating activities. In the first system, antioxidant activity increased with the increasing concentration. At 20.0 mg.ml^?1 concentration, antioxidant property of the oil was 96.8% ± 0.2 and as strong as the positive controls BHT and α-tocopherol. Scavenging effect of the oil was superior to the positive controls BHT and α-tocopherol at 1.5 mg.ml^?1 concentration (96.4% ± 0.1). Reducing power and chelating effect of the essential oil increased with the increasing concentration.     

Error rate analysis for peaky signaling over fading channels

In this paper, the performance of signaling strategies with high peak-to-average power ratio is analyzed in both coherent and noncoherent fading channels. Two modulation schemes, namely on-off phase-shift keying (OOPSK) and on-off frequency-shift keying (OOFSK), are considered. The optimal detector structures are identified and analytical expressions for the error probabilities are obtained for arbitrary constellation sizes. Numerical techniques are employed to compute the error rates. It is concluded that increasing the peakedness of the signals results in reduced error rates for a given power level and hence equivalently improves the energy efficiency for fixed error probabilities.     

On the Capacity and Energy Efficiency of Training-Based Transmissions Over Fading Channels

In this paper, the capacity and energy efficiency of training-based communication schemes employed for transmission over a priori unknown Rayleigh block-fading channels are studied. Initially, the case in which the product of the estimate error and transmitted signal is assumed to be Gaussian noise is considered. In this case, it is shown that bit energy requirements grow without bound as the signal-to-noise ratio (SNR) goes to zero, and the minimum bit energy is achieved at a nonzero SNR value below which one should not operate. The effect of the block length on both the minimum bit energy and the SNR value at which the minimum is achieved is investigated. Flash training and transmission schemes are analyzed and shown to improve the energy efficiency in the low-SNR regime. In the second part of this paper, the capacity and energy efficiency of training-based schemes are investigated when the channel input vector in each coherence block is subject to peak power constraints. The capacity-achieving input structure is characterized and the magnitude distribution of the optimal input is shown to be discrete with a finite number of mass points. The capacity, bit energy requirements, and optimal resource allocation strategies are obtained through numerical analysis. The improvements in energy efficiency when on-off keying (OOK) with fixed peak power and vanishing duty cycle is employed are studied.     

Transient protein-protein interactions

Transient complexes are crucial for diverse biological processes such as biochemical pathways and signaling cascades in the cell. Here, we give an overview of the transient interactions; the importance of transient interactions as drug targets; and the structural characterization of transient protein-protein complexes based on the geometrical and physicochemical features of the transient complexes' interfaces. To better understand and eventually design transient protein-protein interactions (TPPIs), a molecular perspective of the protein-protein interfaces is necessary. Obtaining high-quality structures of protein-protein interactions could be one way of achieving this goal. After introducing the association kinetics of TPPIs, we elaborate on the experimental techniques detecting TPPIs in combination with the computational methods which classify transient and/or non-obligate complexes. In this review, currently available databases and servers that can be used to identify and predict TPPIs are also compiled.     

End product rejection rate and its correlation with melt treatment in direct-chill casted hot rolling slabs

In this study, different melt treatment operations were evaluated and compared to end product’s scrap rate using bifilm index (B_I) method. Results clearly show that degassing with finer gas bubbles increases cleaning performance for the removal of any type of bifilms in the melt. B_I method is a reliable and quick way to determine melt quality at any given time during casting process which is found to have a direct correlation with rejection rate.     

Evaluation of antioxidant activities of 3 edible mushrooms: Ramaria flava (Schaef.: Fr.) Quél., Rhizopogon roseolus (Corda) T.M. Fries., and Russula delica Fr.

The methanolic extracts of Ramaria flava, Rhizopogon roseolus, and Russula delica were analyzed for their antioxidant activities in different test systems including β-carotene/linoleic acid, 1.1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging, reducing power, and metal chelating activities in addition to their total phenolic and flavonoid contents. In the first case, methanol extract of R. roseolus showed the strongest activity. In DPPH system, the scavenging effects increased with the concentration. The reducing power of the mushroom also increased with concentration. Chelating effect was 96.75±0.28% for R. flava. In the case of total phenolic and flavonoid assays, R. flava found to have the highest phenolic content. Total flavonoid content of R. flava again found the superior to the other mushrooms. Experimental results indicate that the mushroom species evaluated here can be consumed safely. On the other hand, knowing the biological activity of these mushrooms will contribute to the establishment of conscious consumption.     

Testing of Drug Release from Bioadhesive Vaginal Tablets

To establish en in vitro test method that can predict the drug release and dissolution behaviour of vaginal bioadhesive controlled release tablets, a system was developed and its appropriateness to the in situ conditions was examined. For this purpose, the dissolution rates of vaginal bioadhesive tablets were measured by three different methods. These were, USP dissolution apparatus two and a new vaginal dissolution tester (NVDT) which was developed by us with some modification of the vaginal tablet desentegration apparatus of BP 1988 and, testing in cow vaginas in situ. Four different bioadhesive tablet formulations were used being composed of the drug and the anionic polymer, polyacrylic acid (PAA) and the nonionic polymers, hydroxypropylmethyl cellulose (HPMC) and ethyIcellulose (EC). The release profiles of the in vitro and in situ methods were investigated and evaluated kinetically.

It was found that NVDT could be used to investigate the drug release from vaginal tablets.     

Designing compressive properties of titanium foams

Titanium foams were produced by optimizing a relatively cheap method, sintering under flowing high purity argon gas with fugitive space holder. Removal of the space holder was conducted by dissolution in hot deionized water which renders it possible to minimize contamination of titanium. Titanium foams having various densities between 20 and 70% were manufactured and systematically characterized. Pore sizes varying from a few microns up to 2 mm were obtained. Compatibility with well known porosity–mechanical property formulations of cellular solids was investigated. Pore sizes in the investigated range were found to have a negligible effect on the elastic portion of compressive stress–strain diagram. High strain rate tests revealed that increasing the strain rate increases compressive strength of the titanium foams produced. The onset strain of densification of the produced titanium foams was determined by the recently developed energy absorption efficiency method. The energy absorbed per unit volume was then calculated by referring to the pre-determined onset strain of densification. A plot of energy absorbed per unit volume (E _A) as a function of relative density (ρ/ρ_s) at various strains (%ε) suggested that the data could be fitted to an equation of the form E _A = A(%ε) ^B (ρ/ρ_s) ^C , where A, B and C are constants, for both fine- and coarse-pored titanium foams.