364 research outputs found

    A Study of Brain Networks Associated with Swallowing Using Graph-Theoretical Approaches

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    Functional connectivity between brain regions during swallowing tasks is still not well understood. Understanding these complex interactions is of great interest from both a scientific and a clinical perspective. In this study, functional magnetic resonance imaging (fMRI) was utilized to study brain functional networks during voluntary saliva swallowing in twenty-two adult healthy subjects (all females, 23.1±1.52 years of age). To construct these functional connections, we computed mean partial correlation matrices over ninety brain regions for each participant. Two regions were determined to be functionally connected if their correlation was above a certain threshold. These correlation matrices were then analyzed using graph-theoretical approaches. In particular, we considered several network measures for the whole brain and for swallowing-related brain regions. The results have shown that significant pairwise functional connections were, mostly, either local and intra-hemispheric or symmetrically inter-hemispheric. Furthermore, we showed that all human brain functional network, although varying in some degree, had typical small-world properties as compared to regular networks and random networks. These properties allow information transfer within the network at a relatively high efficiency. Swallowing-related brain regions also had higher values for some of the network measures in comparison to when these measures were calculated for the whole brain. The current results warrant further investigation of graph-theoretical approaches as a potential tool for understanding the neural basis of dysphagia. © 2013 Luan et al

    Synthetic Receptors for the High-Affinity Recognition of O-GlcNAc Derivatives

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    The combination of a pyrenyl tetraamine with an isophthaloyl spacer has led to two new water-soluble carbohydrate receptors ("synthetic lectins"). Both systems show outstanding affinities for derivatives of N-acetylglucosamine (GlcNAc) in aqueous solution. One receptor binds the methyl glycoside GlcNAc-β-OMe with Ka ≈20,000 m(-1), whereas the other one binds an O-GlcNAcylated peptide with Ka ≈70,000 m(-1). These values substantially exceed those usually measured for GlcNAc-binding lectins. Slow exchange on the NMR timescale enabled structural determinations for several complexes. As expected, the carbohydrate units are sandwiched between the pyrenes, with the alkoxy and NHAc groups emerging at the sides. The high affinity of the GlcNAcyl-peptide complex can be explained by extra-cavity interactions, raising the possibility of a family of complementary receptors for O-GlcNAc in different contexts

    Glycosylation Is Vital for Industrial Performance of Hyperactive Cellulases

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    In the terrestrial biosphere, biomass deconstruction is conducted by microbes employing a variety of complementary strategies, many of which remain to be discovered. Moreover, the biofuels industry seeks more efficient (and less costly) cellulase formulations upon which to launch the nascent sustainable bioenergy economy. The glycan decoration of fungal cellulases has been shown to protect these enzymes from protease action and to enhance binding to cellulose. We show here that thermal tolerant bacterial cellulases are glycosylated as well, although the types and extents of decoration differ from their Eukaryotic counterparts. Our major findings are that glycosylation of CelA is uniform across its three linker peptides and composed of mainly galactose disaccharides (which is unique) and that this glycosylation dramatically impacts the hydrolysis of insoluble substrates, proteolytic and thermal stability, and substrate binding and changes the dynamics of the enzyme. This study suggests that the glycosylation of CelA is crucial for its exceptionally high cellulolytic activity on biomass and provides the robustness needed for this enzyme to function in harsh environments including industrial settings

    Tannin as a renewable raw material for adhesive applications: a review

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    Considering the limits of petrochemical availability and their toxicity, there has been rapid development and innovation in the field of alternatives for petrochemical adhesives. The carcinogenicity of formaldehyde has reduced the demand for formaldehyde-based wood adhesives, which has resulted in the development of adhesives based on renewable resources. This review article summarizes various works published on bio-derived adhesives focusing on tannin. Increasingly acknowledged renewability, sustainability, lower cost, and chemical modification opportunities make tannin a credible precursor for developing competent bio-based adhesives. Henceforth, the chemistry of tannin, its usefulness, possible chemical modification, and compatibility in an attempt to synthesize bio-based adhesives is also being highlighted and compared with its hydrocarbon-derived counterparts. In addition to this, categories of tannin, and techniques available for their extraction along with their pluses and misuses, have also been explained. Moreover, this review includes a detailed discussion on tannin as a raw material for preparing epoxy, polyurethane, polyethylenimine, and furfuryl-based adhesives. It is expected that by exploring further possibilities of chemical modification, tannin can be a potential candidate that can compete with the petrochemical-based adhesives, thereby paving the way for the advancement of bio-adhesives

    Countries with Higher Levels of Gender Equality Show Larger National Sex Differences in Mathematics Anxiety and Relatively Lower Parental Mathematics Valuation for Girls.

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    Despite international advancements in gender equality across a variety of societal domains, the underrepresentation of girls and women in Science, Technology, Engineering, and Mathematics (STEM) related fields persists. In this study, we explored the possibility that the sex difference in mathematics anxiety contributes to this disparity. More specifically, we tested a number of predictions from the prominent gender stratification model, which is the leading psychological theory of cross-national patterns of sex differences in mathematics anxiety and performance. To this end, we analyzed data from 761,655 15-year old students across 68 nations who participated in the Programme for International Student Assessment (PISA). Most importantly and contra predictions, we showed that economically developed and more gender equal countries have a lower overall level of mathematics anxiety, and yet a larger national sex difference in mathematics anxiety relative to less developed countries. Further, although relatively more mothers work in STEM fields in more developed countries, these parents valued, on average, mathematical competence more in their sons than their daughters. The proportion of mothers working in STEM was unrelated to sex differences in mathematics anxiety or performance. We propose that the gender stratification model fails to account for these national patterns and that an alternative model is needed. In the discussion, we suggest how an interaction between socio-cultural values and sex-specific psychological traits can better explain these patterns. We also discuss implications for policies aiming to increase girls' STEM participation

    Aging brain from a network science perspective: Something to be positive about?

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    To better understand age differences in brain function and behavior, the current study applied network science to model functional interactions between brain regions. We observed a shift in network topology whereby for older adults subcortical and cerebellar structures overlapping with the Salience network had more connectivity to the rest of the brain, coupled with fragmentation of large-scale cortical networks such as the Default and Fronto-Parietal networks. Additionally, greater integration of the dorsal medial thalamus and red nucleus in the Salience network was associated with greater satisfaction with life for older adults, which is consistent with theoretical predictions of age-related increases in emotion regulation that are thought to help maintain well-being and life satisfaction in late adulthood. In regard to cognitive abilities, greater ventral medial prefrontal cortex coherence with its topological neighbors in the Default Network was associated with faster processing speed. Results suggest that large-scale organizing properties of the brain differ with normal aging, and this perspective may offer novel insight into understanding age-related differences in cognitive function and well-being. © 2013 Voss et al

    Evaluating Sex and Age Differences in ADI-R and ADOS Scores in a Large European Multi-site Sample of Individuals with Autism Spectrum Disorder

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    Research on sex-related differences in Autism Spectrum Disorder (ASD) has been impeded by small samples. We pooled 28 datasets from 18 sites across nine European countries to examine sex differences in the ASD phenotype on the ADI-R (376 females, 1763 males) and ADOS (233 females, 1187 males). On the ADI-R, early childhood restricted and repetitive behaviours were lower in females than males, alongside comparable levels of social interaction and communication difficulties in females and males. Current ADI-R and ADOS scores showed no sex differences for ASD severity. There were lower socio-communicative symptoms in older compared to younger individuals. This large European ASD sample adds to the literature on sex and age variations of ASD symptomatology

    AI-Powered Vision Assistance for Visually Challenged

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    The world in the 21st century is ever evolving towards automation. This upsurge seemingly has no decline in the foreseeable future. Image recognition is at the forefront of this charge which seeks to revolutionize the way of living of the average man. If robotics can be likened to the creation of a body for computers to live in, then image processing is the development of the part of its brain which deal with identification and recognition of images. To accomplish this task, we developed an object detection algorithm using YOLO, and acronym for “You Only Look Once”. Our algorithm was trained on fifty thousand images and evaluated on ten thousand images and employed a 21 x 21 grid. We also programmed a text generator which randomly creates texts and URLs in an image. A record of useful information about the location of the URLs in the image is also recorded and later passed to the YOLO algorithm for training. At the end of this project, we observed a significant difference in the accuracy of URL detection when using OCR software or our YOLO algorithm. However, our algorithm would be best used to specify the region of interest before converting to texts which greatly improves accuracy when combined with OCR software

    ANALYTICAL METHOD EVELOPMENT AND VALIDATION FOR ANTI ASTHAMATIC DRUG OXYMETAZOLINE HYDROCHLORIDE IN NASAL SPRAY FORMULATIONS BY RP-HPLC

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    A new, simple, accurate and economic reverse-phase HPLC method has been developed for quantification of Oxymetazoline Hydrochloride in nasal spray formulations. This developed method has been validated according to International Conference on Harmonization (ICH) guideline with respect to system suitability, specificity, precision, linearity, accuracy, and robustness. An isocratic condition of mobile phase Phosphate buffer (pH 3.0): Acetonitrile in a ratio of 60:40, v/v at a flow rate of 1.0 mL/minute over RP C18 (octadecylsilane (ODS), 250 × 4.6 mm, 5 µm, ECLIPSE X DB C-18) column at ambient temperature was maintained. This method is specific and showed excellent linear response with correlation coefficient (R2) values of 0.999, which was within the limit of correlation coefficient (R2 0.995). A  simple  and accurate reversed-phase  HPLC  method  for  the  analysis  of  Oxymetazoline Hydrochloride in  nasal spray formulations was developed and validated successfully

    A study of method development and validation for estimation of Azelastine hydrochloride in nasal spray formulations by RP-HPLC method

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    A simple reverse-phase HPLC method for the estimation of Azelastine hydrochloride in nasal spray formulations has been developed. The method is simple, accurate, precise, specific and linear over the analysis range. This developed method has been validated according to International Conference on Harmonization (ICH) guideline with respect to system suitability, specificity, precision, linearity, accuracy, and robustness. An isocratic condition of mobile phase comprising Phosphate buffer (pH 3.1): Acetonitrile in a ratio of 60:40, v/v at a flow rate of 1.0 mL/minute over RP C18 (octadecylsilane (ODS), 250 × 4.6 mm, 5 µm, CHROMOSIL) column at ambient temperature was maintained. Besides, the chromatographic peak was observed sharp & symmetric. The proposed method was successfully applied for the estimation of the Azelastine hydrochloride in nasal spray formulation
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