Quantitative profiling of bacteriocins present in dairy-free probiotic preparations of Lactobacillus acidophilus by nanoliquid chromatography-tandem mass spectrometry

Bacteriocins are a heterogeneous group of ribosomally synthesized peptides or proteins with antimicrobial activity, produced predominantly by lactic acid bacteria, with potential applications as biopreservatives and probiotics. We describe here a novel strategy based on a bottom-up, shotgun proteomic approach using nanoliquid chromatography-tandem mass spectrometry (nanoLC-MS/MS) with multiple fragmentation techniques for the quantitative profiling of bacteriocins present in the probiotic preparations of Lactobacillus acidophilus. A direct LC-MS/MS analysis with alternate collision-induced dissociation, high-energy collision dissociation, and electron-transfer dissociation fragmentation following a filter-assisted size-exclusion sample prefractionation has resulted in the identification of peptides belonging to 37 bacteriocins or related proteins. Peptides from lactacin F, helveticin J, lysin, avicin A, acidocin M, curvaticin FS47, and carocin D were predominant. The process of freeze drying under vacuum was observed to affect both the diversity and abundance of bacteriocins. Data acquisition using alternating complementary peptide fragmentation modes, especially electron-transfer dissociation, has significantly enhanced the peptide sequence coverage and number of bacteriocin peptides identified. Multi-enzyme proteolytic digestion was observed to increase the sample complexity and dynamic range, lowering the chances of detection of low-abundant bacteriocin peptides by LC-MS/MS. An analytical platform integrating size exclusion prefractionation, nanoLC-MS/MS analysis with multiple fragmentation techniques, and data-dependent decision tree-driven bioinformatic data analysis is novel in bacteriocin research and suitable for the comprehensive bioanalysis of diverse, low-abundant bacteriocins in complex samples.     

Synthesis of Ag-Au bimetallic film at liquid-liquid interface and its application in vapor sensing

We demonstrate a novel process for preparing densely packed film of silver nanoparticles at the liquid-liquid interface followed by a transmetallation reaction with gold ion to yield a film of bimetallic nanoparticles. Films of assembled silver as well as Ag-Au bimetallic were characterized by UV-vis-spectroscopy, transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) analysis. I-V measurement shows linear behavior for both the films with ca. five orders of magnitude drop in resistance for the Ag-Au bimetallic film. Temperature dependent I-V measurement revealed a semiconductor to metal transition after transmetallation reaction. The films where checked for their potential application in chemical vapor sensing to ammonia vapors.     

PulsExpert: An expert system for the diagnosis and control of diseases in pulse crops

This paper presents design and development of an expert system for the diagnosis and control of diseases in pulse crops (PulsExpert). PulsExpert is an operational automatic diagnostic tool that helps farmers/extension workers to identify diseases of major pulse crops viz., Chickpea, Pigeonpea, Mungbean and Urdbean (highly consumed pulse crops) and suggests the appropriate control measures. Automatic knowledge acquisition system of PulsExpert provides user-friendly interface to the domain experts for entering, storing and structuring the domain specific knowledge. The knowledge base has been designed after examining the type and structure of the knowledge from different sources like literatures, books, databases, farmers, extension workers, etc. For a particular crop, knowledge can be entered by more than one expert using an automatic knowledge acquisition system and system automatically integrates the knowledge to build a consistent knowledge base. The knowledge base of PulsExpert contains up-to-date knowledge about 19 major diseases of pulses appearing right from seedling to maturity. The system provides user-friendly interface to farmers and asks the textual as well as pictorial questions. The order of questions to be asked is decided dynamically depending upon the answers of the farmer. On the basis of answers, PulsExpert diagnosis the pulse crop diseases along with its confidence factor and suggests most appropriate control measures which are composed of cultural practices as well as chemical controls. PulsExpert was evaluated by a team of field farmers and State Agriculture Officers and it was considered good with an average rank of 2.745 by farmers and 2.075 by State Agriculture Officers with a statistic mode ranking 3 in both the cases.     

An automatic human chromosome metaspread image selection technique

The human chromosome metaspread images are used to generate the karyogram that is used for the diagnosis of the genetic defects. The genetic defects occur due to variation in either the structure of the chromosomes or the number of chromosomes present in the cell. The human chromosome metaspread image selection process is very critical in the karyogram generation task. It is very tedious and time-consuming process and is generally done manually by an expert cytogeneticist. The manual selection results may be biased, and it is possible that the whole search space is not explored to find the best metaspread image. The mood of the cytogeneticist will also greatly affect the selection results. So there is a strong need to automate the process of human chromosome metaspread image selection process. The proposed approach ranks the metaspread images based upon the quality score that is calculated using the count of the chromosomes of various orientations present in the metaspread image. The ranking has been done based upon ordinal ranking process, wherein a unique rank is assigned to each image based upon a set of rules. The rule base aids in the tiebreaking process in case the same quality score is derived for more than one metaspread image. The decision-making process of the expert cytogeneticist has been emulated by using a set of if–then rules. The proposed technique helps to select the best metaspread image, by exploring the complete set of images that can be used for the karyogram generation.     

Pathways from child sexual abuse to adult depression: The role of parental socialization of emotions and alexithymia.

Objective: Depression is common among adult survivors of child sexual abuse (CSA), but the intervening processes responsible for this outcome have not yet been fully delineated. The present study investigated the mediating role of perceived parental emotion socialization and alexithymia (difficulties identifying and describing feelings) in explaining the link between CSA and adult depressive symptoms in female veterans. Method: Cross-sectional data were collected from 110 female veterans who completed self-report questionnaires measuring demographics, sexual victimization history, perceived parental emotion socialization, and current symptoms of alexithymia and depression. Results: Linear regression analyses showed that CSA predicted greater depression, which was partly accounted for by alexithymia. Less positive socialization practices by both parents fully mediated the relationship between CSA and alexithymia. When these factors were examined together in a path model, greater CSA severity predicted perceptions of fewer positive socialization practices by mothers, which, in turn, was associated with greater alexithymia and depression. Conclusions: Perceptions of early positive emotion socialization and current alexithymia may contribute to experience of depression among sexually victimized female veterans. Interventions aimed at targeting emotion regulation skills and perceptions associated with other salient childhood experiences such as emotion socialization by parents could help reduce adult depression among CSA survivors. Furthermore, encouraging positive parenting practices for caregivers of abused children could allay subsequent affective symptoms. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Active vibration control of a beam instrumented with MWCNT/epoxy nanocomposite sensor and PZT-5H actuator,robust to variations in temperature

Microsystem Technologies - Multi walled carbon nano tube (MWCNT)/epoxy nanocomposite strain sensor and piezoelectric actuator pair are used in active vibration control (AVC) of a smart cantilevered...     

Synthesis of gold nanorods in organic media

A seed mediated approach for the synthesis of anisotropic rod shaped gold nanoparticles in organic media (toluene) is demonstrated. Pre-formed gold nanoparticles stabilized in toluene by 4-hexadecylaniline (HDA) are used as seeds. These when reacted with 1-octadecylamine (ODA) hydrophobised chloroaurate ions in toluene lead to the formation of gold nanorods. ODA or alkylamines of different chain lengths which are the chloroaurate ion phase transfer agent have been found to play a key role in the formation of the nanorods. The gold nanorods that have a five-fold symmetry evolve from multiply twinned particles and are bound at the tips by [1 11] faces and at the sides by [100] faces. The gold nanorods have been shown to grow under the shape directing effect of the alkylamines which stabilize the high energy [100] faces. The concentration of the alkylamines has been found to play a critical role in the formation of the gold nanorods. Higher concentrations of the alkylamines lead to formation of spherical particles, at times of narrow size distribution.     

Investigation on structural and electrical properties of BZT ceramics synthesized at low temperature

Abstract

Due to environmental concerns, lead free ceramics such as KNN- NBT and BT have growing interest in applications such as actuators and sensors. Among them Barium Zirconate Titanate (BZT) has become most attractive because it is derived from two perovskite lattice i.e. Barium Titanate (BaTiO₃) and Barium Zirconate (BaZrO₃). It has been reported that Zirconium substitution in titanium lattice enhances the material properties. In the present paper BZT was prepared using solid state route. By adding a mixture of Li₂CO₃ as a sintering aid, the sample could be sintered at 1150?°C having around 94% of the theoretical density. Prepared samples were then subjected to XRD analysis. X-ray diffraction revealed the formation of single phase material. It is observed that the electrical properties of such low-temperature sintered samples are comparable with BZT samples prepared via conventional sintering at a high temperature. It is also observed that the curie temperature shift towards room temperature for a samples sintered at low temperature.