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.     

Timing of enteral feeding in cerebral malaria in resource-poor settings: a randomized trial

Background

Early start of enteral feeding is an established treatment strategy in intubated patients in intensive care since it reduces invasive bacterial infections and length of hospital stay. There is equipoise whether early enteral feeding is also beneficial in non-intubated patients with cerebral malaria in resource poor settings. We hypothesized that the risk of aspiration pneumonia might outweigh the potential benefits of earlier recovery and prevention of hypoglycaemia.

Method and Findings

A randomized trial of early (day of admission) versus late (after 60 hours in adults or 36 hours in children) start of enteral feeding was undertaken in patients with cerebral malaria in Chittagong, Bangladesh from May 2008 to August 2009. The primary outcome measures were incidence of aspiration pneumonia, hypoglycaemia and coma recovery time. The trial was terminated after inclusion of 56 patients because of a high incidence of aspiration pneumonia in the early feeding group (9/27 (33%)), compared to the late feeding group (0/29 (0%)), p = 0.001). One patient in the late feeding group, and none in the early group, had hypoglycaemia during admission. There was no significant difference in overall mortality (9/27 (33%) vs 6/29 (21%), p = 0.370), but mortality was 5/9 (56%) in patients with aspiration pneumonia.

Conclusions

In conclusion, early start of enteral feeding is detrimental in non-intubated patients with cerebral malaria in many resource-poor settings. Evidence gathered in resource rich settings is not necessarily transferable to resource-poor settings.

Trial Registration

Controlled-Trials.com ISRCTN57488577     

Woodland strawberry axillary bud fate is dictated by a crosstalk of environmental and endogenous factors

Plant architecture is defined by fates and positions of meristematic tissues and has direct consequences on yield potential and environmental adaptation of the plant. In strawberries (Fragaria vesca L. and F. × ananassa Duch.), shoot apical meristems can remain vegetative or differentiate into a terminal inflorescence meristem. Strawberry axillary buds (AXBs) are located in leaf axils and can either remain dormant or follow one of the two possible developmental fates. AXBs can either develop into stolons needed for clonal reproduction or into branch crowns (BCs) that can bear their own terminal inflorescences under favorable conditions. Although AXB fate has direct consequences on yield potential and vegetative propagation of strawberries, the regulation of AXB fate has so far remained obscure. We subjected a number of woodland strawberry (F. vesca L.) natural accessions and transgenic genotypes to different environmental conditions and growth regulator treatments to demonstrate that strawberry AXB fate is regulated either by environmental or endogenous factors, depending on the AXB position on the plant. We confirm that the F. vesca GIBBERELLIN20-oxidase4 (FvGA20ox4) gene is indispensable for stolon development and under tight environmental regulation. Moreover, our data show that apical dominance inhibits the outgrowth of the youngest AXB as BCs, although the effect of apical dominance can be overrun by the activity of FvGA20ox4. Finally, we demonstrate that the FvGA20ox4 is photoperiodically regulated via FvSOC1 (F. vesca SUPPRESSOR OF OVEREXPRESSION OF CONSTANS1) at 18°C, but at higher temperature of 22°C an unidentified FvSOC1-independent pathway promotes stolon development.

Environmental conditions and apical dominance dictate woodland strawberry plant architecture by regulating axillary bud fate.     

Adenosine modulation of fat cell responsiveness to insulin and oxytocin

We have investigated the effects of adenosine on the stimulation of glucose oxidation and lipogenesis by oxytocin and insulin in rat epididymal adipocytes. The addition of adenosine deaminase (1 U/ml) to the assay medium reduced the maximal oxytocin response (glucose oxidation and lipogenesis) to between 25 and 50% of the maximum response in control cells. The maximal response to insulin was not appreciably affected under these conditions. The addition of adenosine (10 or 30 microM) increased the cell sensitivity to oxytocin by elevating the maximum rate of oxytocin-stimulated glucose metabolism. Adenosine also increased the cell sensitivity to insulin by decreasing its ED50. A change in ED50, however, was observed only when control or adenosine-treated cells were compared to adenosine deaminase-treated cells; but not when control and adenosine-treated cells were compared. On its own, adenosine also caused an appreciable increase in both glucose oxidation and lipogenesis (ED50 approximately equal to 3 microM adenosine). The difference in the effect of adenosine on oxytocin action, compared with the effect on insulin action, points to differences in the mechanisms by which insulin and oxytocin stimulate glucose metabolism in adipocytes.     

Characterization of fibroblast-like cells from the rat olfactory bulb

The isolation and characterization of stem cells from an alternative tissue is a subject of intensive investigation. In the present study, we have focused on the characterization of fibroblastic cells in olfactory bulb tissue of the rat. To this end, 4-6 week old rats were killed and their olfactory bulb tissue was dissected out. Olfactory bulb derived fibroblast-like cells were recovered by adhesion to cell culture plastic. The plastic adherent cultivated cells were induced to differentiate along osteoblastic, adipogenic and chondrogenic lineages. Furthermore, the expression of some surface antigens was investigated. We obtained purified cells with spindle shaped morphology in primary culture, which differentiated into mesenchymal lineages. These cells expressed CD29 and CD90 (Thy1.1) surface antigens, but not CD31, CD34 and CD45. Our results indicate that fibroblast-like cells from the olfactory bulb are mesenchymal stem cells in nature. Taken together, our data suggest that olfactory bulb tissue may constitute a new source of mesenchymal stem cells and could be used for the treatment of injury.     

Biomarkers of Plasmodium falciparum Infection during Pregnancy in Women Living in Northeastern Tanzania

In pregnant women, Plasmodium falciparum infections are an important cause of maternal morbidity as well as fetal and neonatal mortality. Erythrocytes infected by these malaria-causing parasites accumulate through adhesive interactions in placental intervillous spaces, thus evading detection in peripheral blood smears. Sequestered infected erythrocytes induce inflammation, offering the possibility of detecting inflammatory mediators in peripheral blood that could act as biomarkers of placental infection. In a longitudinal, prospective study in Tanzania, we quantified a range of different cytokines, chemokines and angiogenic factors in peripheral plasma samples, taken on multiple sequential occasions during pregnancy up to and including delivery, from P. falciparum-infected women and matched uninfected controls. The results show that during healthy, uninfected pregnancies the levels of most of the panel of molecules we measured were largely unchanged except at delivery. In women with P. falciparum, however, both comparative and longitudinal assessments consistently showed that the levels of IL-10 and IP-10 increased significantly whilst that of RANTES decreased significantly, regardless of gestational age at the time the infection was detected. ROC curve analysis indicated that a combination of increased IL-10 and IP-10 levels and decreased RANTES levels might be predictive of P. falciparum infections. In conclusion, our data suggest that host biomarkers in peripheral blood may represent useful diagnostic markers of P. falciparum infection during pregnancy, but placental histology results would need to be included to verify these findings.     

Length-weight relationships of seven cyprinid fish species from the Kaptai Lake,Bangladesh

Length-weight relationships (LWRs) were estimated for seven small indigenous cyprinid fish species including Securicula gora, Osteobrama cotio, Esomus lineatus, Pethia gelius, Megarasbora elonga, Gonialosa manmina and Glossogobius aureus occurring in the Kaptai Lake, Bangladesh. Fish were collected monthly basis between March and October, 2018 from fishermen catches landed in the fish landing center, Rangamati. Fishermen operated lift net (mesh size < 0.5 cm), punti net (mesh size < 0.5 cm) and cast net (mesh size < 0.5 cm) for capturing these species. The value of exponent b ranged between 2.769 and 3.212 and regression parameter r² was between 0.926 and 0.992. New maximum total lengths were recorded for E. lineatus and G. manmina in this study.     

Sequence and structural parameters enhancing adaptation of proteins to low temperatures

A systematic analysis compared sequence and structural parameters distributions between 13 pairs of psychrophilic and mesophilic proteins for elucidating the cold adaptation parameters. The results of statistical test (t-test) revealed that helical content, tight turn content, disulfide bonds and hydrogen bonds do not show significant difference between psychrophilic and mesophilic proteins. However, it was demonstrated in this study that a larger proportion of open beta-turn in psychrophilic proteins is an effective parameter in specific activity at low temperature. In addition, substitution of amino acids of charged and aliphatic groups with amino acids of tiny and small groups in protein chains, tight turns and alpha-helices in the direction from mesophilic to psychrophilic proteins is one of the mechanisms of low temperature adaptation. Such sequence and structural parameter differences would help to develop a strategy for designing cold-adapted proteins.