Design and validation of a novel multiplex real-time PCR assay for Vibrio pathogen detection

Three species--Vibrio cholerae, Vibrio parahaemolyticus, and Vibrio vulnificus--account for the majority of vibrio infections in humans. Rapid and accurate identification of Vibrio species has been problematic because phenotypic characteristics are variable within species. Additionally, biochemical identification and confirmation require 2 or more days to complete. Rapid and sensitive molecular techniques for the detection of vibrio pathogens would be useful for the surveillance and management of outbreaks. To facilitate the identification of human-pathogenic species, we designed and validated a highly sensitive, specific, and robust multiplex real-time PCR assay to identify V. cholerae, V. parahaemolyticus, and V. vulnificus using a four-dye configuration in a convenient lyophilized format. Multiple Vibrio strains were sequenced to verify candidate target TaqMan sites. Several individual assays within the multiplex contain multiple primers or probes to ensure detection of polymorphic variants. V. cholerae, V. parahaemolyticus, and V. vulnificus were detected either individually or in mixtures at ≤30 genomic copies. V. cholerae was specifically detected in the presence or absence of Vibrio mimicus. The Vibrio multiplex assay showed 100% specificity to all targets analyzed and no detection of nearest neighbor strains. Each assay exhibited 100% ± 10% efficiency. Multiplex real-time PCR can simplify pathogen detection and reduce costs per test since three species can be analyzed in a single reaction tube. Rapid and accurate detection of pathogenic vibrios in shellfish or seawater samples will improve the microbiological safety of seafood for consumers.     

Thermal properties of silicate esters

Fourteen dimethyldialkoxysilanes are prepared by reacting dimethyldichlorosilane with corresponding alcohols in the liquid phase. Their physicochemical properties are determined by standard methods and their tentative empirical formulae are elucidated. The thermal conductivity values of dimethyldialkoxysilanes are determined using a two slab guarded hot plate apparatus over a temperature range of 30–190°C. The thermal conductivity values of dimethyldialkoxysilanes calculated from empirical equations are found to vary from -14% to +19%. Because thermal conductivity is an important parameter in heat transfer calculations, and to minimise the deviation of the values, new equations involving easily measurable ultrasonic parameters have been formulated. The proposed equations have been tested for the series of dimethyldialkoxysilanes, tetraalkoxysilanes and polydimethylsiloxanes. The thermal conductivity values computed from the proposed equations are comparable with experimental thermal conductivity values. Further, an equation involving the calculation of thermal conductivity values at varying temperatures is also proposed.     

Segmentation and texture analysis of structural biomarkers using neighborhood-clustering-based level set in MRI of the schizophrenic brain

Objective

Schizophrenia (SZ) is a psychiatric disorder that especially affects individuals during their adolescence. There is a need to study the subanatomical regions of SZ brain on magnetic resonance images (MRI) based on morphometry. In this work, an attempt was made to analyze alterations in structure and texture patterns in images of the SZ brain using the level-set method and Laws texture features.

Materials and methods

T1-weighted MRI of the brain from Center of Biomedical Research Excellence (COBRE) database were considered for analysis. Segmentation was carried out using the level-set method. Geometrical and Laws texture features were extracted from the segmented brain stem, corpus callosum, cerebellum, and ventricle regions to analyze pattern changes in SZ.

Results

The level-set method segmented multiple brain regions, with higher similarity and correlation values compared with an optimized method. The geometric features obtained from regions of the corpus callosum and ventricle showed significant variation (p < 0.00001) between normal and SZ brain. Laws texture feature identified a heterogeneous appearance in the brain stem, corpus callosum and ventricular regions, and features from the brain stem were correlated with Positive and Negative Syndrome Scale (PANSS) score (p < 0.005).

Conclusion

A framework of geometric and Laws texture features obtained from brain subregions can be used as a supplement for diagnosis of psychiatric disorders.

     

Macadamia Nut Consumption Modulates Favourably Risk Factors for Coronary Artery Disease in Hypercholesterolemic Subjects

Macadamia nuts are rich source of monounsaturated fats (oleic and palmitoleic acids) and contain polyphenol compounds, therefore, their consumption can be expected to impart health benefits to humans. This study was conducted to examine the effects of consuming macadamia nuts in hypercholesterolemic male individuals on plasma biomarkers of oxidative stress, coagulation and inflammation. Seventeen hypercholesterolemic male subjects were given macadamia nuts (40–90 g/day), equivalent to 15% energy intake, for a period of 4 weeks. As expected, monounsaturated fatty acids (16:1n-7, 18:1n-9 and 20:1n-9) were elevated in the plasma lipids of all volunteers following intervention with macadamia nuts. Plasma markers of inflammation (leukotriene, LTB₄) and oxidative stress (8-isoprostane) were significantly lower (1,353 ± 225 vs. 1,030 ± 129 pg/mL and 876 ± 97 vs. 679 ± 116 pg/mL, respectively) within 4 weeks following macadamia nut intervention. There was a non-significant (23.6%) reduction in the plasma TXB₂/PGI₂ ratio following macadamia nut consumption. This study demonstrates, for the first time, that short-term macadamia nut consumption modifies favourably the biomarkers of oxidative stress, thrombosis and inflammation, the risk factors for coronary artery disease, despite an increase in dietary fat intake. These data, combined with our previous results on cholesterol-lowering effects of macadamia nuts, suggest that regular consumption of macadamia nuts may play a role in the prevention of coronary artery disease.     

Efficient Generation of Electricity from Methane using High Temperature Fuel Cells – Status,Challenges and Prospects

High temperature fuel cells (HTFCs), comprising solid oxide fuel cells and molten carbonate fuel cells, present efficient means for generating electricity from methane and natural gas. The high quality heat generated by HTFCs allows operation in the combined heat and power mode (CHP) to further enhance efficiency. The overall fuel-to-electricity conversion efficiency of an HTFC system operating in CHP mode can approach up to 80 %. Despite the high operating efficiency of HTFCs, high capital costs and durability issues have hindered their widespread commercialization. This article provides an overview of the operating principles, technical challenges, commercialization status of HTFCs, and outlines the strategies being adopted to lower capital costs and increase durability.     

Novel stereo controlled glycosylation of 1,2,3,4,6-penta-o-acetyl-β-d-glucopyranoside using MgO–ZrO2 as an environmentally benign catalyst

Glycosylation reactions are most commonly encountered in nature. Synthetically, glycosylations are carried out with Lewis acid catalysts or mineral acids. However an environmental threat associated with catalysts has encouraged process modification by alternative development of solid catalysts based glycosylation reactions, which are commercially viable as well. In this contribution comparative study of glycosidic bond formation of 1,2,3,4,6-penta-o-acetyl-β-d-glucopyranoside with various alcohols over variety of reaction promoters/catalyst like p-toluene sulphonic acid, HCl, H₂SO₄ and MgO–ZrO₂ were taken up to evaluate the performance of this potential promoter/catalysts systems. The best catalyst for the selective synthesis of alkyl-β-d-glucopyranosides was MgO–ZrO₂ which remains active upto three runs. This replacement of homogeneous acid catalysts by heterogeneous base catalyst shows alkyl-β-d-glucopyranoside as major product at comparatively low temperature range. The effects of variety of parameters were studied in a batch reactor. The mechanism of the reaction over basic mixed metal oxide at 363 K is put forth.     

The entropy of traces in parallel computation

The following problem arises in the context of parallel computation: how many bits of information are required to specify any one element from an arbitrary (non-empty) k-subset of a set? We characterize optimal coding techniques for this problem. We calculate the asymptotic behavior of the amount of information necessary, and construct an algorithm that specifies an element from a subset in an optimal manner     

Nanosheets Based Approach to Elevate the Proliferative and Differentiation Efficacy of Human Wharton’s Jelly Mesenchymal Stem Cells

Mesenchymal stem cell (MSC)-based therapy and tissue repair necessitate the use of an ideal clinical biomaterial capable of increasing cell proliferation and differentiation. Recently, MXenes 2D nanomaterials have shown remarkable potential for improving the functional properties of MSCs. In the present study, we elucidated the potential of Ti₂CTx MXene as a biomaterial through its primary biological response to human Wharton’s Jelly MSCs (hWJ-MSCs). A Ti₂CTx nanosheet was synthesized and thoroughly characterized using various microscopic and spectroscopic tools. Our findings suggest that Ti₂CTx MXene nanosheet exposure does not alter the morphology of the hWJ-MSCs; however, it causes a dose-dependent (10–200 µg/mL) increase in cell proliferation, and upon using it with conditional media, it also enhanced its tri-lineage differentiation potential, which is a novel finding of our study. A two-fold increase in cell viability was also noticed at the highest tested dose of the nanosheet. The treated hWJ-MSCs showed no sign of cellular stress or toxicity. Taken together, these findings suggest that the Ti₂CTx MXene nanosheet is capable of augmenting the proliferation and differentiation potential of the cells.     

BER-Optimal Linear Parallel Interference Cancellation for Multicarrier DS-CDMA in Rayleigh Fading

In this paper, we consider the design and bit-error performance analysis of linear parallel interference cancellers (LPIC) for multicarrier (MC) direct-sequence code division multiple access (DS-CDMA) systems. We propose an LPIC scheme where we estimate and cancel the multiple access interference (MAI) based on the soft decision outputs on individual subcarriers, and the interference cancelled outputs on different subcarriers are combined to form the final decision statistic. We scale the MAI estimate on individual subcarriers by a weight before cancellation. In order to choose these weights optimally, we derive exact closed-form expressions for the bit-error rate (BER) at the output of different stages of the LPIC, which we minimize to obtain the optimum weights for the different stages. In addition, using an alternate approach involving the characteristic function of the decision variable, we derive BER expressions for the weighted LPIC scheme, matched filter (MF) detector, decorrelating detector, and minimum mean square error (MMSE) detector for the considered multicarrier DS-CDMA system. We show that the proposed BER-optimized weighted LPIC scheme performs better than the MF detector and the conventional LPIC scheme (where the weights are taken to be unity), and close to the decorrelating and MMSE detectors.