Sparse NMF based speech enhancement with bases update

In this paper, a combination of methods based on statistical modelling and Non-negative Matrix Factorization (NMF) for speech enhancement using speech and noise bases with on-line update is proposed. Template-based approaches are known to be more robust in the presence of non-stationary noises than methods based on statistical modeling. However, template-based approaches depend on a-priori information. The drawbacks of both the approaches can be avoided by combining them. In NMF approach, speech bases and noise bases are simultaneously adapted to further improve the performance. The proposed method outperforms other benchmark algorithms in terms of perceptual evaluation of speech quality (PESQ) and source-to-distortion ratio (SDR) in stationary and non-stationary noise environment conditions with matched and mismatched noise basis.     

Poly(3-hexylthiophene) and hexafluoro-2-propanol-substituted polysiloxane based OFETs as a sensor for explosive vapor detection

The organic field effect transistors (OFETs) with regioregular poly 3-hexylthiophene (rr-P3HT) and hexafluoro-2-propanol-substituted polysiloxane (SXFA) as an organic layer, have been used for detection of explosive vapors with excellent sensitivity of less than 70 ppt for 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX) and less than 100 ppt for 2,4,6-trinitrotoluene (TNT). The sensor response (% change in saturation current) was found to be 125 ± 10% for TNT and 90 ± 10% for RDX. It was also observed that the incorporation of Cu^II tetraphenylporphyrin (CuTPP) into rr-P3HT/SXFA matrix resulted in an improved selectivity for the vapors of nitro based analytes (TNT, RDX and DNB) as compared to the vapors of non explosive oxidizing agents such as nitrobenzene (NB), benzoquinone (BQ) and benzophenone (BP). This is attributed to the increased binding of the vapors containing nitro compound to the thin films due to the presence of CuTTP. Spin coated thin films were further characterized by Atomic Force Microscopy (AFM) and Electrostatic Force Microscopy (EFM).     

Nitroarenes as Antitubercular Agents: Stereoelectronic Modulation to Mitigate Mutagenicity

Nitroarenes are less preferred in drug discovery due to their potential to be mutagenic. However, several nitroarenes were shown to be promising antitubercular agents with specific modes of action, namely, nitroimidazoles and benzothiazinones. The nitro group in these compounds is activated through different mechanisms, both enzymatic and non‐enzymatic, in mycobacteria prior to binding to the target of interest. From a whole‐cell screening program, we identified a novel lead nitrobenzothiazole (BT) series that acts by inhibition of decaprenylphosphoryl‐β‐d ‐ribose 2′‐epimerase (DprE1) of Mycobacterium tuberculosis (Mtb). The lead was found to be mutagenic to start with. Our efforts to mitigate mutagenicity resulted in the identification of 6‐methyl‐7‐nitro‐5‐(trifluoromethyl)‐1,3‐benzothiazoles (cBTs), a novel class of antitubercular agents that are non‐mutagenic and exhibit an improved safety profile. The methyl group ortho to the nitro group decreases the electron affinity of the series, and is hence responsible for the non‐mutagenic nature of these compounds. Additionally, the co‐crystal structure of cBT in complex with Mtb DprE1 established the mode of binding. This investigation led to a new non‐mutagenic antitubercular agent and demonstrates that the mutagenic nature of nitroarenes can be solved by modulation of stereoelectronic properties.     

Attachment and biofilm formation of Pseudomonas fluorescens PSD4 isolated from a dairy processing line

The effects of different nutrient sources and temperatures on attachment and biofilm formation of Pseudomonas fluorescens PSD4, a dairy isolate, were studied. Initial adherence and attachment capabilities among different strains were studied using microtitre plate assays. Biofilm development was observed using confocal microscopy. Strongly adherent cells were seen in protein rich media. Citrate as a carbon source enhanced biofilm formation. Glucose did not favor biofilm development. Psychrotrophic P. fluorescens PSD4 formed strongly adherent biofilms having high metabolic activities at low temperatures. P. fluorescens PSD4 with spoilage potential was capable of forming strong biofilms in dairy processing environments. Biofilm formation was influenced by nutrient availability and growth conditions. These factors should be considered for design of effective anti-biofilm strategies.     

Pungency threshold of capsaicin produced by in vitro culture of placental tissues of capsicum frutescens mill.

Production of capsaicin in free and immobilized placenta was compared in order to assess their capsaicin production ability. In immobilized placenta, maximum accumulation of capsaicin was on the 14th day of culture with a production of 2045 ug/culture, whereas in free placenta, the accumulation reached maximum on the 7th day (2050ug/culture). It was found that there was no significant difference between free and immobilized placenta in terms of capsaicin production, suggesting that immobilization is not necessary to enhance capsaicin accumulation in piacentai tissue. Pungency threshold of capsaicin produced in in vitro grown free piacentai tissues of Capsicum frutescens was done by Scoville heat units (SHU) method. Pungency analysis of capsaicin produced in free piacentai tissue showed that on day zero, pungency of tissue culture produced capsaicin (0.2267x10⁵ SHU) was comparable to standard natural capsaicin (0.222×10⁵ SHU), while on the 3rd day pungency of tissue culture produced capsaicin (0.3639×10⁵ SHU) was slightly lower than standard natural capsaicin (0.4415×10⁵ SHU).     

X-ray studies on crystalline complexes involving amino acids and peptides XXXIV. Novel mode of aggregation, interaction patterns and chiral effects in the maleic acid complexes of DL- and L- arginine

Amino acid - carboxylic acid complexes provide useful information in relation to molecular interactions in present day biological systems and to prebiotic self-organisation. The crystal structures of the complexes of maleic acid with DL- arginine (orthorhombic; Pca2(1); a=15.9829, b=5.4127, c=16.1885; R=0.0522 for 956 reflections) and L- arginine (triclinic; P1; a=5.2641, b=8.0388, c=9.7860, alpha=106.197, beta=97.275, gamma=101.64; R=0.039 for 1749 reflections) have been determined. The complexes are made up of positively charged zwitterionic arginine molecules and negatively charged semi-maleate ions which contain an intramolecular symmetric O-H-O hydrogen bond. In both the structures, the amino acid molecules aggregate into layers. In each layer, S2 head-to-tail sequences are interconnected through specific intermolecular interactions between alpha-carboxylate and guanidyl groups, an arrangement observed for the first time in crystal structures involving arginine. The carboxylate-guanidyl interactions are of different types in the two complexes and consequently aggregation patterns in them exhibit substantial differences. Interactions between the amino acid layers involve the semi-maleate ions in both the complexes. In addition, water-bridges also exist in the L complex. The full potential of the guanidyl group for specific interactions is realized in both the structures. The L complex contains an array of water-mediated salt bridges. The structures demonstrate that the effect of chirality on molecular aggregation can span a wide range.     

Robust content-based image indexing using contextual clues and automatic pseudofeedback

In this paper we present a robust information integration approach to identifying images of persons in large collections such as the Web. The underlying system relies on combining content analysis, which involves face detection and recognition, with context analysis, which involves extraction of text or HTML features. Two aspects are explored to test the robustness of this approach: sensitivity of the retrieval performance to the context analysis parameters and automatic construction of a facial image database via automatic pseudofeedback. For the sensitivity testing, we reevaluate system performance while varying context analysis parameters. This is compared with a learning approach where association rules among textual feature values and image relevance are learned via the CN2 algorithm. A face database is constructed by clustering after an initial retrieval relying on face detection and context analysis alone. Experimental results indicate that the approach is robust for identifying and indexing person images.Y. Alp Aslandogan: Correspondence to:     

Information technology offshoring in India: a postcolonial perspective

In recent years India has become the information technology (IT) offshoring destination of choice for many Western organizations. From the perspective of vendor organizations in India, however, the IT offshoring phenomenon is more than just a business relationship with Western firms. It is also embedded within the context of the longstanding imbalances of power in the relationship between the West and the East, the implications of which have been largely ignored in empirical work on offshoring within the information systems (IS) discipline. Drawing on concepts from postcolonial theory and using data from our ethnographic fieldwork, we explore the experiences and responses of one Indian vendor organization to asymmetries of power in its relationship with Western client organizations. Our analysis demonstrates how a postcolonial reading and interpretation of IT offshoring adds an important new dimension to previous IS research and also helps to develop a more comprehensive understanding of the strategies deployed by vendor organizations.     

Antimicrobial edible apple films inactivate antibiotic resistant and susceptible Campylobacter jejuni strains on chicken breast

Abstract: Campylobacter jejuni is the leading cause of bacterial diarrheal illness worldwide. Many strains are now becoming multidrug resistant. Apple‐based edible films containing carvacrol and cinnamaldehyde were evaluated for bactericidal activity against antibiotic resistant and susceptible C. jejuni strains on chicken. Retail chicken breast samples inoculated with D28a and H2a (resistant strains) and A24a (a sensitive strain) were wrapped in apple films containing cinnamaldehyde or carvacrol at 0.5%, 1.5%, and 3% concentrations, and then incubated at 4 or 23 °C for 72 h. Immediately after wrapping and at 72 h, samples were plated for enumeration of viable C. jejuni. The antimicrobial films exhibited dose‐ and temperature‐dependent bactericidal activity against all strains. Films with ≥1.5% cinnamaldehyde reduced populations of all strains to below detection at 23 °C at 72 h. At 4 °C with cinnamaldehyde, reductions were variable for all strains, ranging from 0.2 to 2.5 logs and 1.8 to 6.0 logs at 1.5% and 3.0%, respectively. Films with 3% carvacrol reduced populations of A24a and H2a to below detection, and D28a by 2.4 logs at 23 °C and 72 h. A 0.5‐log reduction was observed for both A24a and D28a, and 0.9 logs for H2a at 4 °C at 3% carvacrol. Reductions ranged from 1.1 to 1.9 logs and 0.4 to 1.2 logs with 1.5% and 0.5% carvacrol at 23 °C, respectively. The films with cinnamaldehyde were more effective than carvacrol films. Reductions at 23 °C were greater than those at 4 °C. Our results showed that antimicrobial apple films have the potential to reduce C. jejuni on chicken and therefore, the risk of campylobacteriosis. Possible mechanisms of antimicrobial effects are discussed. Practical Application: Apple antimicrobial films could potentially be used in retail food packaging to reduce C. jejuni commonly present on food.