A Secure and Robust Compressed Domain Video Steganography for Intra- and Inter-Frames Using Embedding-Based Byte Differencing (EBBD) Scheme

This paper presents a novel secure and robust steganographic technique in the compressed video domain namely embedding-based byte differencing (EBBD). Unlike most of the current video steganographic techniques which take into account only the intra frames for data embedding, the proposed EBBD technique aims to hide information in both intra and inter frames. The information is embedded into a compressed video by simultaneously manipulating the quantized AC coefficients (AC-QTCs) of luminance components of the frames during MPEG-2 encoding process. Later, during the decoding process, the embedded information can be detected and extracted completely. Furthermore, the EBBD basically deals with two security concepts: data encryption and data concealing. Hence, during the embedding process, secret data is encrypted using the simplified data encryption standard (S-DES) algorithm to provide better security to the implemented system. The security of the method lies in selecting candidate AC-QTCs within each non-overlapping 8 × 8 sub-block using a pseudo random key. Basic performance of this steganographic technique verified through experiments on various existing MPEG-2 encoded videos over a wide range of embedded payload rates. Overall, the experimental results verify the excellent performance of the proposed EBBD with a better trade-off in terms of imperceptibility and payload, as compared with previous techniques while at the same time ensuring minimal bitrate increase and negligible degradation of PSNR values.     

High-Resolution Denitrification Kinetics in Pasture Soils Link N2O Emissions to pH,and Denitrification to C Mineralization

Denitrification in pasture soils is mediated by microbial and physicochemical processes leading to nitrogen loss through the emission of N₂O and N₂. It is known that N₂O reduction to N₂ is impaired by low soil pH yet controversy remains as inconsistent use of soil pH measurement methods by researchers, and differences in analytical methods between studies, undermine direct comparison of results. In addition, the link between denitrification and N₂O emissions in response to carbon (C) mineralization and pH in different pasture soils is still not well described. We hypothesized that potential denitrification rate and aerobic respiration rate would be positively associated with soils. This relationship was predicted to be more robust when a high resolution analysis is performed as opposed to a single time point comparison. We tested this by characterizing 13 different temperate pasture soils from northern and southern hemispheres sites (Ireland and New Zealand) using a fully automated-high-resolution GC detection system that allowed us to detect a wide range of gas emissions simultaneously. We also compared the impact of using different extractants for determining pH on our conclusions. In all pH measurements, soil pH was strongly and negatively associated with both N₂O production index (IN₂O) and N₂O/(N₂O+N₂) product ratio. Furthermore, emission kinetics across all soils revealed that the denitrification rates under anoxic conditions (NO+N₂O+N₂ μmol N/h/vial) were significantly associated with C mineralization (CO₂ μmol/h/vial) measured both under oxic (r² = 0.62, p = 0.0015) and anoxic (r² = 0.89, p<0.0001) conditions.     

The tumor suppressor p53 is bound to RNA by a stable covalent linkage.

We have previously shown that the carboxyl-terminal tryptic peptide of the tumor suppressor p53 coeluted from reverse-phase high-performance liquid chromatography (HPLC) with ribonucleotides, suggesting the possible linkage of RNA to p53. In this report, we establish that p53 is covalently linked to RNA, using biochemical criteria at the levels of both tryptic peptide and intact protein: the electrophoretic properties of a tryptic peptide containing phosphorylated Ser-389 and the HPLC chromatographic properties of p53 depend on the linked RNA, p53, purified through urea-sodium dodecyl sulfate-polyacrylamide gel electrophoresis and HPLC, copurifies with RNA, and Ser-389 liberates ribonucleotides upon RNase or alkali treatment. Wild-type and mutant p53s from both simian virus 40 (SV40)-transformed and SV40-nontransformed cells are RNA linked, indicating that RNA linkage may be a general property of p53. The RNA is labeled in vivo with 3H-uridine and in vitro by RNA ligase, suggesting that the RNA is bound by a 5' linkage. The RNA is a long-lived, integral component of p53 rather than a transient reaction intermediate. RNA linkage occurs at an evolutionarily conserved site on p53. We propose that RNA-linked p53 is a major biologically active form of p53 and that its interaction with RNA-linked SV40 T antigen reflects a role in RNA metabolism.     

Ultraviolet inactivation and photoreactivation of the cholera phage ‘Kappa’

Summary The lysogenic cholera phage, Kappa is some ten to twenty folds more resistant to UV (254 nm) than are most of the T. phages ofE. coli, or the cholera phage PL 163/10, or the hostV. cholerae strain H218 Sm^r, the 37% (D ₃₇) and 10% (D ₁₀) survival doses being 255.8 J/m² and 633.6 J/m² respectively. The UV-irradiated Kappa phages could be photoreactivated in the hostV. cholerae strain H218 Sm^r to a maximum extent of 40%. The removal of the number of lethal hits per phage by the survival-enhancement treatment (photoreactivation) with time followed an exponential relation, the constant probability of removal of lethal hit per unit time being 2.8 × 10^–2 min^–1. The UV-irradiated phages could also be Weigle reactivated in the host strain H218 Sm^r by a small degree, the maximum reactivation factor (ratio of survivals in UV-irradiated and non-irradiated hosts) being 1.50.     

A simple enzymeimmunoassay of milk progesterone for monitoring fertility in dairy buffaloes

A simple, sensitive, direct (without extraction) enzymeimmunoassay (EIA) was usec to determine progesterone levels in whole milk samples of 400 Nili-Ravi dairy buffaloes. The mean progesterone values 22 d after A.I. were significantly higher in pregnant (16.6 +/- 9.2 ng/ml) than nonpregnant (below 5 ng/ml) animals. The mean progesterone values were below 0.34 +/- 0.12 (the detection limit) both at estrus and in cases of clinically diagnosed inactive ovaries, 3.18 +/- 1.9 at proestrus, 2.25 +/- 1.2 postestrus and 13.22 +/- 6.74 at Day 10 of the estrous cycle. Twenty buffaloes confirmed pregnant for 2 to 3 mo, had a mean value of 20.3 +/- 4.5 ng/ml. The EIA test is very reliable in the selection of nonpregnant buffaloes (100 %) and the confirmation of inactive ovaries and of estrus. Differential diagnosis of inactive or active ovaries can be made by analyzing two milk samples at a 7-d interval.     

Freeze Thaw: A Simple Approach for Prediction of Optimal Cryoprotectant for Freeze Drying

The present study evaluates freeze thaw as a simple approach for screening the most appropriate cryoprotectant. Freeze–thaw study is based on the principle that an excipient, which protects nanoparticles during the first step of freezing, is likely to be an effective cryoprotectant. Nanoparticles of rifampicin with high entrapment efficiency were prepared by the emulsion-solvent diffusion method using dioctyl sodium sulfosuccinate (AOT) as complexing agent and Gantrez AN-119 as polymer. Freeze–thaw study was carried out using trehalose and fructose as cryoprotectants. The concentration of cryoprotectant, concentration of nanoparticles in the dispersion, and the freezing temperature were varied during the freeze–thaw study. Cryoprotection increased with increase in cryoprotectant concentration. Further, trehalose was superior to fructose at equivalent concentrations and moreover permitted use of more concentrated nanosuspensions for freeze drying. Freezing temperature did not influence the freeze–thaw study. Freeze-dried nanoparticles revealed good redispersibility with a size increase that correlated well with the freeze–thaw study at 20% w/v trehalose and fructose. Transmission electron microscopy revealed round particles with a size ∼400 nm, which correlated with photon correlation spectroscopic measurements. Differential scanning calorimetry and X-ray diffraction suggested amorphization of rifampicin. Fourier transfer infrared spectroscopy could not confirm interaction of drug with AOT. Nanoparticles exhibited sustained release of rifampicin, which followed diffusion kinetics. Nanoparticles of rifampicin were found to be stable for 12 months. The good correlation between freeze thaw and freeze drying suggests freeze–thaw study as a simple and quick approach for screening optimal cryoprotectant for freeze drying.     

Analysis and identification of beta-turn types using multinomial logistic regression and artificial neural network

MOTIVATION: So far various statistical and machine learning techniques applied for prediction of beta-turns. The majority of these techniques have been only focused on the prediction of beta-turn location in proteins. We developed a hybrid approach for analysis and prediction of different types of beta-turn. RESULTS: A two-stage hybrid model developed to predict the beta-turn Types I, II, IV and VIII. Multinomial logistic regression was initially used for the first time to select significant parameters in prediction of beta-turn types using a self-consistency test procedure. The extracted parameters were consisted of 80 amino acid positional occurrences and 20 amino acid percentages in beta-turn sequence. The most significant parameters were then selected using multinomial logistic regression model. Among these, the occurrences of glutamine, histidine, glutamic acid and arginine, respectively, in positions i, i + 1, i + 2 and i + 3 of beta-turn sequence had an overall relationship with five beta-turn types. A neural network model was then constructed and fed by the parameters selected by multinomial logistic regression to build a hybrid predictor. The networks have been trained and tested on a non-homologous dataset of 565 protein chains by 9-fold cross-validation. It has been observed that the hybrid model gives a Matthews correlation coefficient (MCC) of 0.235, 0.473, 0.103 and 0.124, respectively, for beta-turn Types I, II, IV and VIII. Our model also distinguished the different types of beta-turn in the embedded binary logit comparisons which have not carried out so far. AVAILABILITY: Available on request from the authors.     

Murine mesenchymal stem cells isolated by low density primary culture system

Murine mesenchymal stem cells (mMSC) and the difficult task of isolation and purification of them have been the subject of rather extensive investigation. The present study sought to isolate these cells from two different mouse strains, one outbred and the other inbred, primarily through a relatively simple but novel approach, the most important feature of which was the low density primary culture of bone marrow cells. For this purpose, mononuclear cells from either NMRI or BALB/c bone marrow were plated at about 500 cells per well of 24-well plates and incubated for 7 days. At this point, the fibroblastic clones that had emerged were pooled together and expanded through several subcultures. To investigate the mesenchymal nature, we differentiated the cells into the osteoblastic, chondrocytic and adipocytic lineages in different subcultures up to passage 10. According to the results, 1 week after culture initiation, several clones each comprising several fibroblastic cells appeared in each plate. The cells from different passages were capable of differentiating into corresponding skeletal tissues. In the present investigation, the best culture condition for maximum proliferation and also the expression of certain surface marker on isolated cells were examined. In this term the two murine strains showed some differences.