403 research outputs found
Nanocomposite Nafion-Silica membranes for direct methanol fuel cells
Commercially available proton exchange membranes such as Nafion do not meet the requirements for high power density direct methanol fuel cells, partly due to their high methanol permeability. The aim of this work is to develop a new class of high-proton conductivity membranes, with thermal and mechanical stability similar to Nafion and reduced methanol permeability. Nanocomposite membranes were produced by the in-situ sol-gel synthesis of silicon dioxide particles in preformed Nafion membranes. Microstructural modification of Nafion membranes with silica nanoparticles was shown in this work to reduce methanol crossover from 7.48x10-6 cm2s^-1 for pure Nafion® to 2.86 x10-6 cm2s^-1 for nanocomposite nafion membranes (Methanol 50% (v/v) solution, 75 degrees C). Best results were achieved with a silica composition of 2.6% (w/w). We propose that silica inhibits the conduction of methanol through Nafion by blocking sites necessary for methanol diffusion through the polymer electrolyte membrane. Effects of surface chemistry, nanoparticle formation and interactions with Nafion matrix are further addressed
Can metal organic frameworks outperform adsorptive removal of harmful phenolic compound 2-chlorophenol by activated carbon?
Removal of persistent organic compounds from aqueous solutions is generally achieved using adsorbent like activated carbon (AC) but it suffers from limited adsorption capacity due to low surface area. This paper describes a pioneering work on the adsorption of an organic pollutant, 2-chlorophenol (2-CP) by two MOFs with high surface area and water stability; MIL-101 and its amino-derivative, MIL-101-NH2. Although MOFs have higher surface area than AC, the latter was proven better having the highest equilibrium 2-CP uptake (345 mg g−1), followed by MIL-101 (121 mg g−1) and MIL-101-NH2 (84 mg g−1). Used MIL-101 could be easily regenerated multiple times by washing with ethanol and even showed improved adsorption capacity after each washing cycle. These results can open the doors to meticulous adsorbent selection for treating 2-CP-contaminated water
Developing Critical Thinking in Female Teacher Candidates at SQU: A Predictive Model
The purpose of this paper was to articulate the way in which socio-cultural factors
influence the propensity for critical thinking among female teacher candidates at Sultan Qaboos University (SQU) in Oman. The sample consisted of 274. Twelve independent variables were ascertained, relating to key Omani institutions and forms of socio-cultural capital. A significant model to predict critical thinking identified religious beliefs and practices, family support for a knowledge society, valuing individual qualities (motivation participation and learning outcomes) over other forms of capital, and the state’s endorsement of the role of teachers as loyal civil servants and trusted agents of change. Implications for teacher education programs and future research are also presented
Solvent‐induced enantioselectivity reversal in a chiral metal organic framework
Solvent-induced enantioselectivity reversal is a rarely reported phenomenon in porous homochiral materials. Similar behavior has been studied in chiral high performance liquid chromatography, where minor modifications to the mobile phase can induce elution order reversal of two enantiomers on a chiral stationary phase column. We report the first instance of solvent-induced enantioselectivity reversal in a homochiral metal organic framework. Further, we highlight the complex enantioselectivity behavior of homochiral metal organic frameworks toward racemic mixtures in the presence of solvents through racemate-solvent enantioselectivity and loading experiments as well as enantiopure-solvent loading experiments. We hypothesize that this interesting selectivity reversal behavior is likely to be observed in other competitive adsorption, nonchiral selective processes involving a solvent
Solvent‐induced enantioselectivity reversal in a chiral metal organic framework
Solvent-induced enantioselectivity reversal is a rarely reported phenomenon in porous homochiral materials. Similar behavior has been studied in chiral high performance liquid chromatography, where minor modifications to the mobile phase can induce elution order reversal of two enantiomers on a chiral stationary phase column. We report the first instance of solvent-induced enantioselectivity reversal in a homochiral metal organic framework. Further, we highlight the complex enantioselectivity behavior of homochiral metal organic frameworks toward racemic mixtures in the presence of solvents through racemate-solvent enantioselectivity and loading experiments as well as enantiopure-solvent loading experiments. We hypothesize that this interesting selectivity reversal behavior is likely to be observed in other competitive adsorption, nonchiral selective processes involving a solvent
An improved microRNA annotation of the canine genome
The domestic dog, Canis familiaris, is a valuable model for studying human diseases. The publication of the latest Canine genome build and annotation, CanFam3.1 provides an opportunity to enhance our understanding of gene regulation across tissues in the dog model system. In this study, we used the latest dog genome assembly and small RNA sequencing data from 9 different dog tissues to predict novel miRNAs in the dog genome, as well as to annotate conserved miRNAs from the miRBase database that were missing from the current dog annotation. We used both miRCat and miRDeep2 algorithms to computationally predict miRNA loci. The resulting, putative hairpin sequences were analysed in order to discard false positives, based on predicted secondary structures and patterns of small RNA read alignments. Results were further divided into high and low confidence miRNAs, using the same criteria. We generated tissue specific expression profiles for the resulting set of 811 loci: 720 conserved miRNAs, (207 of which had not been previously annotated in the dog genome) and 91 novel miRNA loci. Comparative analyses revealed 8 putative homologues of some novel miRNA in ferret, and one in microbat. All miRNAs were also classified into the genic and intergenic categories, based on the Ensembl RefSeq gene annotation for CanFam3.1. This additionally allowed us to identify four previously undescribed MiRtrons among our total set of miRNAs. We additionally annotated piRNAs, using proTRAC on the same input data. We thus identified 263 putative clusters, most of which (211 clusters) were found to be expressed in testis. Our results represent an important improvement of the dog genome annotation, paving the way to further research on the evolution of gene regulation, as well as on the contribution of post-transcriptional regulation to pathological conditions
Sex-specific Trans-regulatory Variation on the Drosophila melanogaster X Chromosome
The X chromosome constitutes a unique genomic environment because it is present in one copy in males, but two copies in females. This simple fact has motivated several theoretical predictions with respect to how standing genetic variation on the X chromosome should differ from the autosomes. Unmasked expression of deleterious mutations in males and a lower census size are expected to reduce variation, while allelic variants with sexually antagonistic effects, and potentially those with a sex-specific effect, could accumulate on the X chromosome and contribute to increased genetic variation. In addition, incomplete dosage compensation of the X chromosome could potentially dampen the male-specific effects of random mutations, and promote the accumulation of X-linked alleles with sexually dimorphic phenotypic effects. Here we test both the amount and the type of genetic variation on the X chromosome within a population of Drosophila melanogaster, by comparing the proportion of X linked and autosomal trans-regulatory SNPs with a sexually concordant and discordant effect on gene expression. We find that the X chromosome is depleted for SNPs with a sexually concordant effect, but hosts comparatively more SNPs with a sexually discordant effect. Interestingly, the contrasting results for SNPs with sexually concordant and discordant effects are driven by SNPs with a larger influence on expression in females than expression in males. Furthermore, the distribution of these SNPs is shifted towards regions where dosage compensation is predicted to be less complete. These results suggest that intrinsic properties of dosage compensation influence either the accumulation of different types of trans-factors and/or their propensity to accumulate mutations. Our findings document a potential mechanistic basis for sex-specific genetic variation, and identify the X as a reservoir for sexually dimorphic phenotypic variation. These results have general implications for X chromosome evolution, as well as the genetic basis of sex-specific evolutionary change
Receptor-targeted liposome-peptide-siRNA nanoparticles represent a novel and efficient therapeutic approach to prevent conjunctival fibrosis.
There is increasing evidence that the Myocardin-related transcription factor/Serum response factor (MRTF/SRF) pathway plays a key role in fibroblast activation and that knocking down MRTF can lead to reduced scarring and fibrosis. Here, we have developed a receptor-targeted liposome-peptide-siRNA nanoparticle as a non-viral delivery system for MRTF-B siRNA in conjunctival fibrosis. Using 50 nM siRNA, the MRTF-B gene was efficiently silenced by 76% and 72% with LYR and LER nanoparticles, respectively. The silencing efficiency was low when non-targeting peptides or siRNA alone or liposome-siRNA alone were used. LYR and LER nanoparticles also showed higher silencing efficiency than PEGylated LYR-P and LER-P nanoparticles. The nanoparticles were not cytotoxic using different liposomes, targeting peptides, and 50 nM siRNA. Three-dimensional fibroblast-populated collagen matrices were also used as a functional assay to measure contraction in vitro, and showed that MRTF-B LYR nanoparticles completely blocked matrix contraction after a single transfection treatment. In conclusion, this is the first study to develop and show that receptor-targeted liposome-peptide-siRNA nanoparticles represent an efficient and safe non-viral siRNA delivery system that could be used to prevent fibrosis after glaucoma filtration surgery and other contractile scarring conditions in the eye
Holistic forecasting for future pandemics: a review of pathogens, models, and data
Pandemics challenge the capacity and resilience of healthcare systems around the world. A rapid and effective response to the sudden spread of a pathogen is therefore key to minimising the burden of a disease. Epidemic forecasting generates possible future scenarios of disease spread that can inform the decision-making process of public health authorities, leading to the timely implementation of efficient control strategies. Here, we provide an overview of the pathogens that possess the potential to cause future pandemics, the different models, and the data sources that can be employed to generate prognoses about their spread. Existing efforts focus mainly on one or two different sources, failing to account for multiple factors that influence disease transmission. We discuss recent developments that can lead us towards a holistic forecasting system capable of integrating different data sources, which, we argue, is needed to make reliable predictions and ensure a timely response by public health authorities at a global scale.1 Introduction 2 Literature search 3 Pathogens 3.1 Airborne pathogens 3.2 Pathogens transmitted through contact with contaminated fluids or surfaces 3.3 Vector‑borne diseases 4 Disease forecasting models 4.1 Mechanistic models 4.1.1 Compartmental models 4.1.2 Agent‑based models 4.2 Machine learning models 4.2.1 Statistical learning models 4.2.2 Deep learning models 4.3 Ensemble and hybrid forecasting models 5 Data sources for pandemic forecasting 5.1 Epidemiological data 5.1.1 Animal disease surveillance 5.1.2 Environmental surveillance 5.2 Internet queries and social media data 5.3 Mobility data 5.4 Climate data 5.5 Genomic data 5.6 Image data 6 Future perspectives 7 Conclusio
Data collection in multimodal language and communication research: A flexible decision framework
The contemporary study of human language and communication has expanded beyond its traditional focus on spoken and written forms to incorporate gestures, facial expressions, and sign languages. This shift has been accompanied by methodological advancements that extend beyond classical tools such as tape recorders or video cameras and include motion-tracking systems, depth cameras, and multimodal data fusion techniques. While these tools enable richer empirical insights, they also introduce significant conceptual and practical challenges, particularly for researchers new to multimodal data collection. This paper provides a structured exploration of the methodological workflow essential to multimodal language and communication research. We present a flexible decision-making framework that guides researchers through key considerations, from data selection and its alignment with research questions, to data collection methods, technical requirements, and data management, including ethical considerations and data sharing. We also address critical factors such as equipment choice, data synchronization, and ethical concerns (e.g., privacy and data protection) while illustrating these processes with examples from different research contexts (i.e., lab-based experiments, large-scale annotated corpora, field studies including non-human primates). Rather than advocating a one-size-fits-all approach, our discussion emphasizes key decision points, trade-offs and real-world examples to help researchers navigate the complexities of multimodal data collection. By integrating perspectives from different disciplines, our flexible decision-making framework is intended as a practical tool for newcomers to address common conceptual and methodological challenges in the rapidly developing area of multimodal data collection
- …
