Assessing arsenic leachability from pulverized cement concrete produced from arsenic-laden solid CalSiCo-sludge

Synthetically prepared arsenic-laden CalSiCo-sludge was converted to pulverized cement concrete (PCC) using solidification/stabilization technology with cement. Batch leaching experiments were conducted to estimate the leaching of As(III) and As(V) from the CalSiCo-sludge as well as from the PCC. The leaching of As(III) and As(V) was found to be the function of time, pH and concentration of anions such as Cl(-), NO(3)(-), and SO(4)(2-) present in the extraction fluid. It is observed that from the CalSiCo-sludge the leaching of As(III) is >0.05mg/l (which is above the permissible limit for arsenic in drinking water) at any pH. But in case of As(V) the leaching is >0.05mg/l only at pH>8 and at pH<4. It is noted that maximum leaching occurs when the extraction liquid contains Cl(-). In contrary, NO(3)(-) and SO(4)(2-) have negligible effect on arsenic leaching from the CalSiCo-sludge. Extraction tests were carried out to determine the maximum leachable concentration under the chosen conditions of leaching medium and leaching time. Leaching of As(III) and As(V) from exhausted arsenic-laden CalSiCo-sludge and from PCC was carried out in both tap water and rain water. It was noticed that tap water has no effect in leaching of arsenic from CalSiCo-sludge but rain water causes significant amount of leaching, which is mostly due to pH effect. However, in all cases the leaching of As(III) was more than that of As(V). When compared with CalSiCo-sludge PCC showed negligible leaching of arsenic. It was noticed further that the variation of 28 days compressive strength was within 15% of the original strength after replacing 35% cement with exhausted CalSiCo-sludge.     

Antibodies to Listeria monocytogenes

Listeria monocytogenes is one of the leading foodborne pathogens and has been implicated in numerous outbreaks in the last 2 decades. Immunocompromised populations are usually the most susceptible to Listeria infections. Although the pathogenic mechanism is a complex process, significant progress has been made in unravelling the mechanism in recent years. It is now clear that numerous extracellular and cell-associated proteins, such as internalin, listeriolysin, actin polymerization protein, phospholipase, metalloprotease, and possibly p60 proteins, are essential for L. monocytogenes entry into mammalian cells, survival inside the phagosome, escape into the cytoplasm, and cell-to-cell spread. Other proteins may be responsible for growth and physiology or to maintain the structural integrity of the bacteria. Monoclonal and polyclonal antibodies have been developed against many of those antigens or their synthetic derivatives that have helped greatly to determine the structure and function of these antigens. The antibodies were also used for the diagnosis and detection, immunocytochemical staining, and serotyping of Listeria. Humoral immune response to live L. monocytogenes cells was examined in naturally or experimentally infected hosts. Studies revealed that only extracellular antigens induced the humoral response, whereas cell-associated antigens had apparently no response. It is speculated that during the occasional bacteremic phase, L. monocytogenes releases extracellular antigens that are then processed by the immune system for antibody production. As L. monocytogenes is an intracellular pathogen, the cell-associated antigens are not persistent in the blood circulation and thus fail to stimulate the humoral immune response.     

A novel method for binarization of scene text images and its application in text identification

Pattern Analysis and Applications - The aim of this article is twofold. First, we propose an effective methodology for binarization of scene images. For our present study, we use the publicly...     

Effect of Secondary Structure and Side Chain Length of Hydrophobic Amino Acid Residues on the Antimicrobial Activity and Toxicity of 14-Residue-Long de novo AMPs

Herein we report the efficacy and toxicity of three de novo designed cationic antimicrobial peptides (AMPs) LL-14, VV-14 and ββ-14, where side chains of the hydrophobic amino acids were reduced gradually. The AMPs showed broad-spectrum antimicrobial activity against three pathogens from the ESKAPE group and two fungal strains. This study showed that side chains which are either too long or too short increase toxicity and lower antimicrobial activity, respectively. VV-14 was found to be non-cytotoxic and highly potent under physiological salt concentrations against several pathogens, especially Salmonella typhi TY2. These AMPs acted via membrane deformation, depolarization, and lysis. The activity of the AMPs is related to their ability to take on amphipathic helical conformations in the presence of microbial membrane mimics. Among AMPs with the same charge, hydrophobic interactions between the side chains of the residues with cell membrane lipids determine their antimicrobial potency and cytotoxicity. Strikingly, an optimum hydrophobic interaction is the crux of generating highly potent non-cytotoxic AMPs.     

Room Temperature Magnetism in Free-Standing Nano-Ni/PVDF Composites

Nanocrystalline Ni was incorporated in polyvinylidene fluoride (PVDF) in three different proportions to obtain free-standing flexible film by sol-gel technique. Effect of nano-Ni loading in the PVDF matrix on the optical, microstructural, and magnetic properties of the nano-Ni/PVDF composite material was studied. Variation of magnetic moments with magnetic field at different temperatures was recorded in the composite-free-standing films. X-ray photoelectron spectroscopy studies indicated that incorporated Ni was in Ni²⁺ and Ni⁴⁺ states. Ni²⁺ atomic concentration was found to be significantly larger than Ni⁴⁺ concentration in all the samples suggesting Ni²⁺ in the PVDF lattice are responsible for observed room temperature ferromagnetism.     

Blends of high density polyethylene and poly(l‐lactic acid): Mechanical and thermal properties

The blends of high‐density polyethylene (HDPE) and poly(l ‐lactic acid) (PLLA) were prepared by melt blending method in an extrusion mixer with a postextrusion blown film attachment. The ratios of HDPE/PLLA blends were taken as 100/0, 95/5, 90/10, 85/15, and 80/20. The 80/20 blend was further compatibilized by adding maleic anhydride‐grafted polyethylene in different ratios (up to 8 wt%). Based on the mechanical properties of the films, the compositions HDPE80 (80% HDPE and 20% PLLA) and HD80C4 (80% HDPE, 20% PLLA, and 4% compatibilizer) were found to be optimum and considered for further analysis. The thermal properties of these selected blends were investigated by means of thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). TGA study revealed that the addition of the PLLA somewhat decreased the thermal stability of HDPE. DSC investigation showed that the blends were partially miscible only. X‐ray diffraction (XRD) analysis enlightened that the crystallinity of blends was slightly increased with addition of PLLA. Immiscibility of the two polymers was diminished in the presence of compatibilizer, as indicated by the scanning electron microscopy (SEM) of the blends. These partially biodegradable blends may be used for flexible packaging applications. POLYM. ENG. SCI., 54:2155–2160, 2014. © 2013 Society of Plastics Engineers     

Color image compression based on block truncation coding using pattern fitting principle

This paper describes a color image compression technique based on block truncation coding using pattern fitting (BTC-PF). High degree of correlation between the RGB planes of a color image is reduced by transforming them to O₁O₂O₃ planes. Each O_i plane (1?i?3) is then encoded using BTC-PF method. Size of the pattern book and the block size are selected based on the information content of the corresponding plane. The result of the proposed method is compared with that of several BTC based methods and the former is found superior. Though this method is a spatial domain technique, it is also compared with JPEG compression method, which is one of most popular frequency domain techniques. It is found that the performance of the proposed method is a little inferior to that of the JPEG in terms of quality of the reconstructed image. Decoding time is another important criterion where the compressed image is decoded frequently for various purposes. As the proposed method requires negligible decoding time compared to JPEG, the former is preferred over the latter in those cases.     

Neighborhood granules and rough rule-base in tracking

This paper deals with several new methodologies and concepts in the area of rough set theoretic granular computing which are then applied in video tracking. A new concept of neighborhood granule formation over images is introduced here. These granules are of arbitrary shapes and sizes unlike other existing granulation techniques and hence more natural. The concept of rough-rule base is used for video tracking to deal with the uncertainties and incompleteness as well as to gain in computation time. A new neighborhood granular rough rule base is formulated which proves to be effective in reducing the indiscernibility of the rule-base. This new rule-base provides more accurate results in the task of tracking. Two indices to evaluate the performance of tracking are defined. These indices do not need ground truth information or any estimation technique like the other existing ones. All these features are demonstrated with suitable experimental results.     

Multiplex fiber optic biosensor for detection of Listeria monocytogenes, Escherichia coli O157:H7 and Salmonella enterica from ready-to-eat meat samples

Listeria monocytogenes, Escherichia coli O157:H7 and Salmonella enterica are the most common foodborne bacterial pathogens and are responsible for many outbreaks. Therefore, multiplex detection of these three using a single assay platform is highly desirable. The objective was to develop and optimize a fiber optic sensor for simultaneous detection of these three from food. The streptavidin coated optical waveguides were immobilized with biotinylated polyclonal antibodies and exposed to the bacterial suspensions or enriched food samples for 2 h. Pathogens were detected after reacting with Alexa-Fluor 647-labeled monoclonal antibodies. Ready-to-eat beef, chicken and turkey meats were inoculated with each pathogen (∼100 cfu/25 g), enriched in SEL (Salmonella, E. coli, Listeria), a multipathogen selective enrichment broth for 18 h and tested with the biosensor. The biosensor was able to detect each pathogen, individually or in a mixture with very little cross-reactivity. The limit of detection for the sensor was ∼10³ cfu/ml for all three pathogens. Furthermore, the biosensor successfully detected each pathogen, grown in a mixture from enriched meat samples under 24 h. The pathogen presence was further verified by PCR and immunofluorescence assay. The multiplex fiber optic sensor shows promise for detection of the three pathogens if present in the same sample eliminating the use of multiple single pathogen detection platforms.