An effective digital image watermarking scheme incorporating DCT, DFT and SVD transformations.

Image watermarking prevents copyright infringements by attaching visible/invisible watermark images as authentication identities in the owner's documents. The article made analysis on the advantages of different transformations for choosing better combinations to make the watermark embedding process and observed that watermarking techniques incorporating discrete cosine transform (DCT) provide better resistance towards JPEG based potential attacks, discrete Fourier transform (DFT) has strong energy compaction with geometrical invariance properties to resist geometric attacks while singular value decomposition (SVD) provides stability, proportion invariance and rotation invariance properties and it provides strong resistance against noise based attacks. Considering these advantages of different transformations, the article presents a new non-blind watermarking algorithm by utilizing advantages of DFT, DCT and SVD transforms while attaching secret contents in cover images. The algorithm starts by applying DFT followed by onion peel decomposition (OPD) for decomposing Fourier domain carrier image to four frequency sub images. The scheme then applies DCT on the frequency bands and orders them in zigzag fashion to form four individual frequency arrays. In the final step of embedding process, it embeds four copies of watermark singular value contents in DFT domain with the carrier image singular value contents to produce the watermarked image. The experimental results based on subjective and objective metrics on various test images from standard image databases with different test conditions demarcate the stability of new algorithm in producing high quality watermarked images with fewer distortions even when the watermarked images are extremely distorted by potential attacks.

Thromboelastograph:A prognostic marker in sepsis with organ dysfunction without overt bleeding.

BACKGROUND: Coagulation abnormalities are not infrequent in sepsis. It is unclear if abnormalities in thromboelastogram (TEG) are associated with mortality in patients with severe sepsis without overt bleeding. MATERIALS AND METHODS: In this prospective study, patients were categorised as those with normal coagulation, hypercoagulable or hypercoagulable state based on admission TEG parameters (R time, K time, Maximum amplitude (MA), α angle). Their association with mortality was explored using Fisher's exact and Mann-Whitney U test as appropriate. RESULTS: The study cohort (n = 87; 49 male) with median (IQR) age 51 (42-60) years and admission SOFA score 8 (6-11) included scrub typhus (24.1%), pneumonia (22.6%) and urosepsis (10.3%). Non-invasive and invasive ventilation and vasopressors were required in 28.1%, 68.9% and 74%, respectively. Mortality was 24.1%. Based on R time, K time and α angle, 3.5% to 9.3% had a hypercoagulable state and 26.7 to 29.9% were hypocoagulable. Prolonged R time (p = 0.04) and reduced alpha angle (p = 0.01) in patients with hypocoagulable state was associated with mortality. K time, α angle and MA were significantly different in patients requiring transfusion (p < 0.001). CONCLUSION: A subset of patients with severe sepsis without overt bleeding are hypocoagulable. Hypocoagulability is associated with mortality and need for transfusion.

Chemical Solution Deposition of Ordered 2D Arrays of Room-Temperature Ferrimagnetic Cobalt Ferrite Nanodots.

Over the past decades, the development of nano-scale electronic devices and high-density memory storage media has raised the demand for low-cost fabrication methods of two-dimensional (2D) arrays of magnetic nanostructures. Here, we present a chemical solution deposition methodology to produce 2D arrays of cobalt ferrite (CFO) nanodots on Si substrates. Using thin films of four different self-assembled block copolymers as templates, ordered arrays of nanodots with four different characteristic dimensions were fabricated. The dot sizes and their long-range arrangement were studied with scanning electron microscopy (SEM) and grazing incident small-angle X-ray scattering (GISAXS). The structural evolution during UV/ozone treatment and the following thermal annealing was investigated through monitoring the atomic arrangement with X-ray absorption fine structure spectroscopy (EXAFS) and checking the morphology at each preparation step. The preparation method presented here obtains array types that exhibit thicknesses less than 10 nm and blocking temperatures above room temperature (e.g., 312 K for 20 nm diameter dots). Control over the average dot size allows observing an increase of the blocking temperature with increasing dot diameter. The nanodots present promising properties for room temperature data storage, especially if a better control over their size distribution will be achieved in the future.

Controlling the volatility of the written optical state in electrochromic DNA liquid crystals.

Liquid crystals are widely used in displays for portable electronic information display. To broaden their scope for other applications like smart windows and tags, new material properties such as polarizer-free operation and tunable memory of a written state become important. Here, we describe an anhydrous nanoDNA-surfactant thermotropic liquid crystal system, which exhibits distinctive electrically controlled optical absorption, and temperature-dependent memory. In the liquid crystal isotropic phase, electric field-induced colouration and bleaching have a switching time of seconds. Upon transition to the smectic liquid crystal phase, optical memory of the written state is observed for many hours without applied voltage. The reorientation of the DNA-surfactant lamellar layers plays an important role in preventing colour decay. Thereby, the volatility of optoelectronic state can be controlled simply by changing the phase of the material. This research may pave the way for developing a new generation of DNA-based, phase-modulated, photoelectronic devices.

Nanoscale ferroelectric and piezoelectric properties of Sb2S3 nanowire arrays.

We report the first observation of piezoelectricity and ferroelectricity in individual Sb(2)S(3) nanowires embedded in anodic alumina templates. Switching spectroscopy-piezoresponse force microscopy (SS-PFM) measurements demonstrate that individual, c-axis-oriented Sb(2)S(3) nanowires exhibit ferroelectric as well as piezoelectric switching behavior. Sb(2)S(3) nanowires with nominal diameters of 200 and 100 nm showed d(33(eff)) values around 2 pm V(-1), while the piezo coefficient obtained for 50 nm diameter nanowires was relatively low at around 0.8 pm V(-1). A spontaneous polarization (P(s)) of approximately 1.8 µC cm(-2) was observed in the 200 and 100 nm Sb(2)S(3) nanowires, which is a 100% enhancement when compared to bulk Sb(2)S(3) and is probably due to the defect-free, single-crystalline nature of the nanowires synthesized. The 180° ferroelectric monodomains observed in Sb(2)S(3) nanowires were due to uniform polarization alignment along the polar c-axis.