De-noising of 3D multiple-coil MR images using modified LMMSE estimator.

De-noising is a crucial topic in Magnetic Resonance Imaging (MRI) which focuses on less loss of Magnetic Resonance (MR) image information and details preservation during the noise suppression. Nowadays multiple-coil MRI system is preferred to single one due to its acceleration in the imaging process. Due to the fact that the model of noise in single-coil and multiple-coil MRI systems are different, the de-noising methods that mostly are adapted to single-coil MRI systems, do not work appropriately with multiple-coil one. The model of noise in single-coil MRI systems is Rician while in multiple-coil one (if no subsampling occurs in k-space or GRAPPA reconstruction process is being done in the coils), it obeys noncentral Chi (nc-χ). In this paper, a new filtering method based on the Linear Minimum Mean Square Error (LMMSE) estimator is proposed for multiple-coil MR Images ruined by nc-χ noise. In the presented method, to have an optimum similarity selection of voxels, the Bayesian Mean Square Error (BMSE) criterion is used and proved for nc-χ noise model and also a nonlocal voxel selection methodology is proposed for nc-χ distribution. The results illustrate robust and accurate performance compared to the related state-of-the-art methods, either on ideal nc-χ images or GRAPPA reconstructed ones.

Physicochemical properties of Carum copticum essential oil loaded chitosan films containing organic nanoreinforcements.

The aim of this research was to prepare of bionanocomposite films based on chitosan (CH) incorporated with Carum copticum essential oil and reinforced with cellulose nanofibers (CNF) or lignocellulose nanofibers (LCNF). The FTIR analysis showed new interactions in bionanocomposites. AFM and SEM analyses showed an increased roughness for bionanocomposites but suggested good dispersion of CNF and LCNF in CH matrix. X-ray diffraction confirmed that the degree of crystallinity was increased by addition of CNF/LCNF. The results suggested that the CH-EO film had high antioxidant activity and was more effective against E. coli and B. cereus bacteria than CH-EOCNF and CH-EO-LCNF films, which shows the release controlling effect of nanofibers. Mechanical properties were improved with addition of EO and CNF/LCNF. Incorporation of EO and CNF/LCNF improved water vapor barrier properties of films. In general, uniform dispersion and improving effect of LCNF on properties of CH-EO films was more than CNF.

Effective removal of toxic metal ions from aqueous solutions: 2-Bifunctional magnetic nanocomposite base on novel reactive PGMA-MAn copolymer@Fe3O4 nanoparticles.

In this study, effective novel magnetic nanocomposite particles (MNCPs) were prepared based on iminodiacetic acid grafted poly (glycidylmethacrylate-maleicanhydride) (PGMA-MAn) copolymer. For this purpose, firstly Fe3O4 nanoparticles reacted with 3-aminopropyl triethoxysilane for the production of magnetite nanoparticles containing amine groups (MNPs-NH2). Then iminodiacetic acid reacted with PGMA-MAn copolymer to produce iminodiacetic acid grafted PGMA-MAn copolymer (ID-g-PGMA-MAn). Finally, the MNPs-NH2 reacted with the ID-g-PGMA-MAn and the reaction was completed by propylenediamine (PDA) to produce MNCPs. Structure, magnetic property, size, and porosity of the prepared magnetic nanocomposite were investigated by FT-IR, XRD, VSM, EDX, SEM and BET analyses. The ability of these MNCPs for removing Pb(II) and Cd(II) from water and wastewater was studied, and the effects of different parameters (pH, adsorbent dosage, metal ion concentration, contact time and agitation) on the adsorption process were investigated. The isotherm models were used to describe adsorption equilibrium. The results showed that the best fit was achieved with the Langmuir isotherm equation, yielding maximum adsorption capacities of 53.33 and 48.53mg/g for Pb(II) and Cd(II), respectively. The kinetics equations were used for modeling of adsorption data and it was shown that pseudo-second-order kinetic equation could best describe the adsorption kinetics. Furthermore, phenol pollutant can be removed effectively by metal ions of the nanocomposite-metal complex; therefore, the synthesized adsorbent was useful not only in recovering toxic metal ions but also in the treating phenol pollutants in wastewater.

Suppression of noise in SEM images using weighted local hysteresis smoothing filter.

It has been proven that Hysteresis Smoothing (HS) has several advantages for Scanning Electron Microscopy (SEM) image noise reduction. HS uses hysteresis thresholding to remove noise besides preserving important details of images. Determination of optimal threshold values (cursor width) plays an effective role in improving the performance of HS based filters. Recently, a novel local technique, named Local Adaptive Hysteresis Smoothing (LAHS), has been proposed to compute an optimal cursor width. In this paper, a new method is proposed to improve the performance of LAHS in noise reduction and detail preservation. In the proposed approach which is based on weighted averaging, local statistical characteristics of the image are used in order to modify the final values of estimated pixels by LAHS method. Proposed method is applied to SEM images corrupted by different levels of noise. Noise reduction and detail preservation performance of the proposed method is compared in both objective and subjective manners with other HS based filters. Experimental results demonstrate that the proposed method is successful in improving the performance of LAHS and also it achieves better performance in noise reduction besides detail preservation of SEM images in comparison with other HS based filters. SCANNING 38:634-643, 2016. © 2016 Wiley Periodicals, Inc.

Isolation and identification of viral hemorrhagic septicemia virus (VHSV) from farmed rainbow trout (Oncorhynchus mykiss) in Iran.

Viral hemorrhagic septicemia virus (VHSV) is a rhabdovirus that causes one of the most important fish diseases in rainbow trout (Oncorhynchus mykiss) production industry. During the present study from October 2014 to July 2015, the virus causing viral hemorrhagic septicemia (VHS) was isolated and identified in rainbow trout farms from five of sixteen farms experiencing mass mortalities in six provinces of Iran with major trout production. Cumulative mortalities at VHSV-positive farms ranged from 30 to 70%. Clinical signs of disease included exophthalmia, petechial hemorrhages in the mandible and around the eyes, a swollen abdomen and darkening of the integument, widespread petechiae of the musculature and pyloric regions, severe congestion of the kidney, and pale enlarged livers. In addition, histopathologic examinations of tissues showed severe lesions in muscle, kidney and liver, which were compatible with those already described for VHS. Furthermore, homogenates tissues of diseased fish induced cytopathic effects (CPE) in CHSE-214 cells, and confirmatory diagnosis of VHS was made by RT-PCR reactions. To our knowledge, this is the first report of isolation and identification of VHSV from farmed trout in Iran, which may have originated from Europe.

Protective and immunogenic effects of Escherichia coli-expressed infectious pancreatic necrosis virus (IPNV) VP2-VP3 fusion protein in rainbow trout.

Infectious Pancreatic Necrosis Virus (IPNV) is a member of the family Birnaviridae which causes significant losses in the aquaculture industry. To develop a recombinant vaccine for IPNV, a cDNA construct of IPNV VP2-VP3 fusion gene was prepared and cloned into an Escherichia coli (E. coli) expression vector (pET-26b) to obtain recombinant protein products. A study was conducted to determine the antibody responses and protective capacity of this recombinant vaccine expressing VP2-VP3 fusion protein. Subsequently, juvenile rainbow trout were inoculated by injecting purified recombinant IPNV VP2-VP3 proteins, followed by challenge with virulent IPNV in rainbow trout. Our results demonstrate that recombinant E. coli derived VP2-VP3 fusion protein induced a strong and significantly (P < 0.05) higher IgM antibody response in serum samples compared to control groups. Following intraperitoneal challenge, the relative percent survival (RPS) rate of survivors was 83% for the vaccinated group. Statistical analysis of IgM levels indicated that immunogenicity of recombinant VP2-VP3 protein, combined with adjuvant, was much higher than any other groups of rainbow trout challenged with virulent IPNV. This result was confirmed by measuring the viral loads of IPNV in immunized rainbow trout which was drastically reduced, as analyzed by real-time RT-PCR. In summary, we demonstrate that E. coli-expressed IPNV VP2-VP3 injectable vaccine is highly immunogenic and protective against IPNV infection.

An Optimized LMMSE Based Method for 3D MRI Denoising.

Post-acquisition denoising of magnetic resonance (MR) images is an important step to improve any quantitative measurement of the acquired data. In this paper, assuming a Rician noise model, a new filtering method based on the linear minimum mean square error (LMMSE) estimation is introduced, which employs the self-similarity property of the MR data to restore the noise-less signal. This method takes into account the structural characteristics of images and the Bayesian mean square error (Bmse) of the estimator to address the denoising problem. In general, a twofold data processing approach is developed; first, the noisy MR data is processed using a patch-based L(2)-norm similarity measure to provide the primary set of samples required for the estimation process. Afterwards, the Bmse of the estimator is derived as the optimization function to analyze the pre-selected samples and minimize the error between the estimated and the underlying signal. Compared to the LMMSE method and also its recently proposed SNR-adapted realization (SNLMMSE), the optimized way of choosing the samples together with the automatic adjustment of the filtering parameters lead to a more robust estimation performance with our approach. Experimental results show the competitive performance of the proposed method in comparison with related state-of-the-art methods.

Facile synthesis of PSMA-g-3ABA/MWCNTs nanocomposite as a substrate for hemoglobin immobilization: application to catalysis of H(2)O(2).

The new nanocomposite films based on poly(styrene-alternative-maleic anhydride) grafted to 3-aminobenzoic acid (PSMA-g-3ABA) and multi-walled carbon nanotubes (MWCNTs) were applied to immobilize hemoglobin (Hb) for biosensor fabrication (PSMA-g-3ABA/MWCNTs). Electrochemical impedance spectroscopy was used to confirm the adsorption of Hb onto the surface of PSMA-g-3ABA/MWCNTs. The immobilized Hb maintains its bioactivities and displays an excellent electrochemical behavior. The biosensor was used to catalyze the reduction of hydrogen peroxide. The electrocatalytic response showed a linear dependence on the H2O2 concentration ranging widely from 1.0×10(-6)M to 5.0×10(-4)M with a detection limit of 3.2×10(-7)M. The apparent Michaelis-Menten constant of Hb on the modified electrode was estimated to be 0.22mM. The proposed method opens a way to develop biosensors by using nanostructured materials with low electrical conductivity.

Sequence analysis of infectious pancreatic necrosis virus isolated from Iranian reared rainbow trout (Oncorhynchus mykiss) in 2012.

Infectious pancreatic necrosis virus (IPNV) is the causal agent of a highly contagious disease that affects many species of fish and shellfish. This virus causes economically significant diseases of farmed rainbow trout, Oncorhynchus mykiss (Walbaum), in Iran, which is often associated with the transmission of pathogens from European resources. In this study, moribund rainbow trout fry samples were collected during an outbreak of IPNV in three different fish farms in north and west provinces of Iran in 2012; and we investigated the full genome sequence of Iranian IPNV and compared it with previously identified IPNV sequences. The sequences of different structural and nonstructural-protein genes were compared to those of other aquatic birnaviruses sequenced to date. Our results show that the Iranian isolate falls within genogroup 5, serotype A2 strain SP, having 99% identity with the strain 1146 from Spain. These results suggest that the Iranian isolate may have originated from Europe.

An MRI denoising method using image data redundancy and local SNR estimation.

This paper presents an LMMSE-based method for the three-dimensional (3D) denoising of MR images assuming a Rician noise model. Conventionally, the LMMSE method estimates the noise-less signal values using the observed MR data samples within local neighborhoods. This is not an efficient procedure to deal with this issue while the 3D MR data intrinsically includes many similar samples that can be used to improve the estimation results. To overcome this problem, we model MR data as random fields and establish a principled way which is capable of choosing the samples not only from a local neighborhood but also from a large portion of the given data. To follow the similar samples within the MR data, an effective similarity measure based on the local statistical moments of images is presented. The parameters of the proposed filter are automatically chosen from the estimated local signal-to-noise ratio. To further enhance the denoising performance, a recursive version of the introduced approach is also addressed. The proposed filter is compared with related state-of-the-art filters using both synthetic and real MR datasets. The experimental results demonstrate the superior performance of our proposal in removing the noise and preserving the anatomical structures of MR images.