Measurement of the echo reduction for underwater acoustic passive materials by using the time reversal technique

A measuring method of the echo reduction of passive materials by using the time reversal（TR） technique is presented. To measure the echo reduction of a sample with this approach, the received signals are firstly focused according to the TR theory. Then, the sample is removed and the TR processing is again employed to realize the focus of the received signal.Finally, the echo reduction of the sample is evaluated with these focusing signals. Besides, to calibrate the measured echo reduction via the TR technique, a standard sample is employed to measure a constant coefficient that only depends on the measurement environment. An aluminum plate sample and a steel plate sample with the same size of 1.1 mxl.O m x0.005 m axe tested in a wave guide tank. The experimental results show that the calibrated values are well consistent with theoretical results under the free field at the measured frequency range of0.5-20 kHz. The relative errors of all the measured values are less than 10% and the values of the expanded uncertainty are less than 1.5 dB. The TR processing focuses the energy in spatial domain and temporal domain, so it can be used to measure the echo reduction of passive materials in the environments with reflections induced by boundaries and low frequency sources.

Measurement of insertion loss for underwater acoustic passive materials with the time reversal technique

A method using the time reversal（TR） technique to measure the insertion loss（IL） of passive materials is presented.Firstly the received signals are focused according to the TR theory when there is not a sample between the source and the received array.Then,the sample is placed near the received array and the TR processing is again employed to realize the focus of the received signal.Finally,the IL of the sample is evaluated from these focusing signals.Because the TR processing can focus the energy in spatial domain and time domain,the method can be used to measure acoustic properties of passive materials in a waveguide tank with reflections induced by boundaries or with low source frequencies.Two samples with the same size of 1.1 m×1.0 m×5 mm are tested in the waveguide tank.The method is demonstrated by the comparison of the theoretical and the experimental results in the measured frequency range of 1-20 kHz.

Creation of reversed phase high-performance liquid chromatographic technique to assay platelet-activating factor

Objective: To establish a new assay for platelet-activating factor (PAF), to compare it with bio-assay; and to discuss its significance in some elderly people diseases such as cerebral infarction and coronary heart disease. Methods: To measure PAF levels in 100 controls, 23 elderly patients with cerebral infarction and 65 cases with coronary heart disease by reversed phase high-performance liquid chromatographic technique (rHPLC). Results:rHPLC is more convenient, sensitive,specific, and less confusing, compared with bio-assay. The level of plasma PAF in patients with cerebral infarction was higher than that in the controls (P<0.01), and in patients with coronary heart disease. Conclusion: Detection of PAF with rHPLC is more reliable and more accurate. The new assay has important significance in PAF research.

Payload Capacity Scheme for Quran Text Watermarking Based on Vowels with Kashida

The most sensitive Arabic text available online is the digital Holy Quran.This sacred Islamic religious book is recited by all Muslims worldwide including non-Arabs as part of their worship needs.Thus,it should be protected from any kind of tampering to keep its invaluable meaning intact.Different characteristics of Arabic letters like the vowels(),Kashida(extended letters),and other symbols in the Holy Quran must be secured from alterations.The cover text of the Quran and its watermarked text are different due to the low values of the Peak Signal to Noise Ratio(PSNR)and Embedding Ratio(ER).A watermarking technique with enhanced attributes must,therefore,be designed for the Quran’s text using Arabic vowels with kashida.The gap addressed by this paper is to improve the security of Arabic text in the Holy Quran by using vowels with kashida.The purpose of this paper is to enhance the Quran text watermarking scheme based on a reversing technique.The methodology consists of four phases:The first phase is a pre-processing followed by the second phase-the embedding process phase—which will hide the data after the vowels.That is,if the secret bit is“1”,then the kashida is inserted;however,the kashida is not inserted if the bit is“0”.The third phase is the extraction process and the last phase is to evaluate the performance of the proposed scheme by using PSNR(for the imperceptibility)and ER(for the capacity).The experimental results show that the proposed method of imperceptibility insertion is also optimized with the help of a reversing algorithm.The proposed strategy obtains a 90.5%capacity.Furthermore,the proposed algorithm attained 66.1%which is referred to as imperceptibility.

Anti-tumor Effect of Newcastle Disease Virus Expressing IL-2 in Lung Cancer Model

Recombinant Newcastle disease virus(rNDV)has shown an anti-cancer effect in preclinical studies,but has never been tested for lung cancer models.This study explored the anti-cancer activity of genetically modified NDV expressing IL-2(rNDV–IL-2)in lung cancer models.This study used Lewis lung carcinoma cell line(LLC)to create tumor models in C57 female mice,the tumor-bearing mice were treated with rNDV-IL-2,rNDV and phosphate-buffered saline(PBS),respectively.In vitro results revealed that rNDV effectively infected malignant cells and expressed IL-2,in vivo results revealed that rNDV expressing IL-2 was highly efficient in inhibiting lung cancer tumors,with an average tumor size of 291.255 mm^3 in rNDV-IL-2 group compared to 763.068 mm^3 in rNDV group and 1101.68 mm^3 in PBS group.For the survival studies,treatment with rNDV-IL-2 enhanced the survival rates of tumor-bearing mice by 36%compared to those of rNDV treated mice and by 80%compared to those of vehicle-treated mice(survival rate:12 out of 15 for rNDV-IL-2 group;seven out of 15 for rNDV group and zero out of 15 for vehicle group).These results demonstrated that rNDV-expressed IL-2 enhanced the intrinsic anti-tumor ability of Newcastle disease virus in lung cancer models by further restrain of lung tumor growth and improvement of the survival rates of the tumor-bearing mice.The genetically modified rNDV-IL-2 was a good candidate for lung cancer therapy.

Recent Advances in Protein Extraction and Chiral Separation of Biomolecules

Reverse micelles create unique environment in organic media. They are capable of solubilizing hydrophilic biomolecules （e.g., proteins, peptides, amino acids, and DNAs） in their aqueous interior. This feature brings about the practical use of biomaterials in organic media because reverse micelles solubilize them with the intrinsic activity. In this paper, we focus on recent two topics concerning protein extraction and chiral separation of biomolecules using liquid membranes. In the first topic, we present recent attempts to extract proteins from an aqueous solution into isooctane using reverse micelles, and some important operational parameters to achieve an efficient protein transfer are discussed. Furthermore, novel function of reverse micelles as a protein activation medium is introduced. In the reverse micellar phase, denatured proteins were completely reactivated in the reverse micellar solution. The reverse micellar technique is found to be a useful tool not only for protein separation but also for protein refolding. Furthermore, we found that a cyclic ligand carixarene has an extraction ability to set up optimum conditions for protein transfer. In the second topic, we have found that a supported liquid membrane （SLM） encapsulating enzymes shows high enantioselectivity （enantioselective excess value is over 96%） in the transport of racemic pharmaceutical compound ibuprofen. A different experiment also suggests that the α-chymotrypsin-catalyzed reactions droved the enantioselective transport of L-phenylalanine based on the enantioselectivity of the enzyme. The SLM encapsulating the surfactant-enzyme complex enabled the highly enantioselective separation of racemic mixtures. It can be envisioned that arrangement of appropriate enzymes in the SLM system will allow enantioselective separation of various useful organic compounds.