637 research outputs found
Marriage and Social Identity in The Return of the Native
The Return of the Native presents a world in which “doing means marrying". Thomas Hardy shows how the dominant discourse of the Victorian society defines an individual’s whole life through the conformity to the social code of marriage. This paper clarifies how Hardy’s satirical tone implicitly reflects the voice of the minority, which is not able or eager to follow this conformity code of the majority. Through a detailed analysis of the significance of marriage in defining one’s social identity, family relations, economic ambitions, and individual ideals, the paper focuses on a hermaphrodite character who cannot adapt to the majority’s code because of his physical condition. Such an individual, as the paper presents, is marginalized by the majority and suffers from problems that might lead to psychological disorders. It is Hardy’s implicit satirical tone, which encourages the readers to change their mental set about the role of marriage in defining one’s identity
The Role of Natural Laccase Redox Mediators in Simultaneous Dye Decolorization and Power Production in Microbial Fuel Cells
Redox mediators could be used to improve the efficiency of microbial fuel cells (MFCs) by enhancing electron transfer rates and decreasing charge transfer resistance at electrodes. However, many artificial redox mediators are expensive and/or toxic. In this study, laccase enzyme was employed as a biocathode of MFCs in the presence of two natural redox mediators (syringaldehyde (Syr) and acetosyringone (As)), and for comparison, a commonly-used artificial mediator 2,2′-azinobis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) was used to investigate their influence on azo dye decolorization and power production. The redox properties of the mediator-laccase systems were studied by cyclic voltammetry. The presence of ABTS and As increased power density from 54.7 ± 3.5 mW m−2 (control) to 77.2 ± 4.2 mW m−2 and 62.5 ± 3.7 mW m−2 respectively. The power decreased to 23.2 ± 2.1 mW m−2 for laccase with Syr. The cathodic decolorization of Acid orange 7 (AO7) by laccase indicated a 12–16% increase in decolorization efficiency with addition of mediators; and the Laccase-Acetosyringone system was the fastest, with 94% of original dye (100 mgL−1) decolorized within 24 h. Electrochemical analysis to determine the redox properties of the mediators revealed that syringaldehyde did not produce any redox peaks, inferring that it was oxidized by laccase to other products, making it unavailable as a mediator, while acetosyringone and ABTS revealed two redox couples demonstrating the redox mediator properties of these compounds. Thus, acetosyringone served as an efficient natural redox mediator for laccase, aiding in increasing the rate of dye decolorization and power production in MFCs. Taken together, the results suggest that natural laccase redox mediators could have the potential to improve dye decolorization and power density in microbial fue
Wearable Nano-Based Gas Sensors for Environmental Monitoring and Encountered Challenges in Optimization
With a rising emphasis on public safety and quality of life, there is an urgent need to ensure optimal air quality, both indoors and outdoors. Detecting toxic gaseous compounds plays a pivotal role in shaping our sustainable future. This review aims to elucidate the advancements in smart wearable (nano)sensors for monitoring harmful gaseous pollutants, such as ammonia (NH3), nitric oxide (NO), nitrous oxide (N2O), nitrogen dioxide (NO2), carbon monoxide (CO), carbon dioxide (CO2), hydrogen sulfide (H2S), sulfur dioxide (SO2), ozone (O3), hydrocarbons (CxHy), and hydrogen fluoride (HF). Differentiating this review from its predecessors, we shed light on the challenges faced in enhancing sensor performance and offer a deep dive into the evolution of sensing materials, wearable substrates, electrodes, and types of sensors. Noteworthy materials for robust detection systems encompass 2D nanostructures, carbon nanomaterials, conducting polymers, nanohybrids, and metal oxide semiconductors. A dedicated section dissects the significance of circuit integration, miniaturization, real-time sensing, repeatability, reusability, power efficiency, gas-sensitive material deposition, selectivity, sensitivity, stability, and response/recovery time, pinpointing gaps in the current knowledge and offering avenues for further research. To conclude, we provide insights and suggestions for the prospective trajectory of smart wearable nanosensors in addressing the extant challenges
Application of Magnetic Field for Improvement of Microbial Productivity
Continued attempt by the industry and research sectors to improve productivity of commercially viable microbial
products fall into three general approaches including microbial-based (e.g. isolation, selection, and manipulation
of microbes as higher producers), environmental-based (e.g. media development), and bioreactor/bioprocessbased
studies.
Application of electromagnetic field to microbial cultures is a recent bioprocess-based technique. Current
literature shows some effects on characteristics of microbial species (fungi and bacteria). These include
enhancement of ethanol production capacity of Saccharomyces cerevisiae, citric acid and cellulase production
by Aspergillus niger species and insulase production by Geotrichum candidum after the cultures were exposed
to electromagnetic field.
In this paper we report the application of electromagnetic field to cultures of Bacillus licheniformis to enhance
productivity of bacitracin, a water-soluble branched polypeptide used as an antimicrobial agent against grampositive
and some gram-negative bacteria. Electromagnetic field was applied on cultures of B. licheniformis in
stirred tank reactors (STRs) with working volume of 1.5 litres circulating into an in-house designed and
constructed magnetic field generator with low magnetic field intensity. The experiments were carried out both
with and without pH control of the culture. Samples were assayed for bacitracin concentration to confirm the
effects of electromagnetic field. The microbial growth and pH profiles were also monitored.
The results showed that circulation of culture at flow rate of 10 mL.min-1 into magnetic field with 10 millitesla
intensity leads to an increase in bacitracin concentration. The increase was higher when the pH of the culture
was controlled compared to non-controlled culture. The highest percentage increase in bacitracin concentration
was 36 % after 35 hours without pH control, while the highest bacitracin percentage increase obtained from the
controlled culture under pH 7 exposed to electromagnetic field, was almost 89 % after 43 hours
Development of an electroactive aerobic biocathode for microbial fuel cell applications
Microbial biocathodes are gaining interest due to their low cost, environmental friendliness and sustainable nature. In this study, a microbial consortium was enriched from activated sludge obtained from a common textile effluent treatment plant in the absence of organic carbon source to produce an electroactive biofilm. Chronoamperometry method of enrichment was carried out for over 70 days to select for electroactive bacteria that could be used as a cathode catalyst in microbial fuel cells (MFC). The resultant biofilm produced an average peak current of −0.7 mA during the enrichment and produced a maximum power density of 64.6 ± 3.5 mW m−2 compared to platinum (72.7 ± 1.2 mW m−2) in a Shewanella-based MFC. Microbial community analysis of the initial sludge sample and enriched samples, based on 16S rRNA gene sequencing, revealed the selection of chemolithotrophs with the most dominant phylum being Bacteroidetes, Proteobacteria, Firmicutes, Actinobacteria and Acidobacteria in the enriched samples. A variety of CO2 fixing and nitrate-reducing bacteria was present in the resultant biofilm on the cathode. This study suggests that microbial consortia are capable of replacing expensive platinum as a cathode catalyst in MFCs
Magnetic properties of Ruddlesden-Popper phases SrY(FeNi)O: A combined experimental and theoretical investigation
We present a comprehensive study of the magnetic properties of
SrY(FeNi)O ().
Experimentally, the magnetic properties are investigated using superconducting
quantum interference device (SQUID) magnetometry and neutron powder diffraction
(NPD). This is complemented by the theoretical study based on density
functional theory as well as the Heisenberg exchange parameters. Experimental
results show an increase in the N\'eel temperature () with the increase of
Y concentrations and O occupancy. The NPD data reveals all samples are
antiferromagnetically ordered at low temperatures, which has been confirmed by
our theoretical simulations for the selected samples. Our first-principles
calculations suggest that the 3D magnetic order is stabilized due to finite
inter-layer exchange couplings. The latter give rise to a finite inter-layer
spin correlations which disappear above the
Effect of methylene blue on wetting characteristics of quartz/H2/brine systems: Implication for hydrogen geological storage
Hydrogen (H2) is considered a promising replacement for fossil fuels due to its enormous potential as an environmentally friendly and sustainable option compared to carbon-based fossil fuels. However, storing the vast quantity of H2 required to satisfy the global energy demand on the earth\u27s surface can be difficult due to its compressibility and volatility. The best option for large-scale storage is underground H2 storage (UHS), which can be retrieved when needed. Rock wettability is vital in UHS because it determines the H2 storage capacity, containment security, and potential withdrawal and injection rates. Organic acid inherent in storage formations could make the storage rock H2-wet and reduce the residually trapped H2; thus, recent research efforts have concentrated on modifying sandstone formations contaminated with organic acid through chemical injections, such as nanofluids and methyl orange. However, previous research has not considered applying methylene blue (MB) as a rock wettability modifier to promote successful UHS. In addition, MB is a toxic constituent of wastewater, causing pollution. This research aims to dispose of MB in underground reservoirs to alter the wettability and increase the H2 storage capacity, mitigating anthropogenic carbon dioxide emissions. We assess the application of MB as a chemical agent for altering the wettability of quartz contaminated with stearic acid to promote H2 geological storage. Based on the contact-angle measurements, quartz aged with the optimum concentration of MB (100 mg/L) has the least advancing ( a= 35°), and receding ( r= 32°) angles at 13 MPa and 50 °C, changing the wettability to strongly water-wet. We demonstrate that an injection of MB into geological formations could make the rock water-wet, promoting H2 containment security and assisting in the large-scale implementation of UHS
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Total Sitting Time and Sitting Pattern in Postmenopausal Women Differ by Hispanic Ethnicity and are Associated With Cardiometabolic Risk Biomarkers.
Background Sedentary behavior is pervasive, especially in older adults, and is associated with cardiometabolic disease and mortality. Relationships between cardiometabolic biomarkers and sitting time are unexplored in older women, as are possible ethnic differences. Methods and Results Ethnic differences in sitting behavior and associations with cardiometabolic risk were explored in overweight/obese postmenopausal women (n=518; mean±SD age 63±6 years; mean body mass index 31.4±4.8 kg/m2). Accelerometer data were processed using validated machine-learned algorithms to measure total daily sitting time and mean sitting bout duration (an indicator of sitting behavior pattern). Multivariable linear regression was used to compare sitting among Hispanic women (n=102) and non-Hispanic women (n=416) and tested associations with cardiometabolic risk biomarkers. Hispanic women sat, on average, 50.3 minutes less/day than non-Hispanic women (P<0.001) and had shorter (3.6 minutes less, P=0.02) mean sitting bout duration. Among all women, longer total sitting time was deleteriously associated with fasting insulin and triglyceride concentrations, insulin resistance, body mass index and waist circumference; longer mean sitting bout duration was deleteriously associated with fasting glucose and insulin concentrations, insulin resistance, body mass index and waist circumference. Exploratory interaction analysis showed that the association between mean sitting bout duration and fasting glucose concentration was significantly stronger among Hispanic women than non-Hispanic women (P-interaction=0.03). Conclusions Ethnic differences in 2 objectively measured parameters of sitting behavior, as well as detrimental associations between parameters and cardiometabolic biomarkers were observed in overweight/obese older women. The detrimental association between mean sitting bout duration and fasting glucose may be greater in Hispanic women than in non-Hispanic women. Corroboration in larger studies is warranted
Evaluation of effective factors on low birth weight infants' mortality using path analysis
Background: This study have conducted in order to determine of direct or indirect effective factors on mortality of neonates with low birth weight by path analysis. Methods: In this cohort study 445 paired mothers and their neonates were participated in Tehran city. The data were gathered through an answer sheet contain mother age, gestational age, apgar score, pregnancy induced hypertension (PIH) and birth weight. Sampling was convenience and neonates of women were included in this study who were referred to 15 government and private hospitals in Tehran city. Live being status of neonates was determined until 24 hours after delivery. Results: The most changes in mortality rate is related to birth weight and its negative score means that increasing in weight leads to increase chance of live being. Second score is related to apgar sore and its negative score means that increasing in apgar score leads to decrease chance of neonate death. Third score is gestational age and its negative score means that increasing in weight leads to increase chance of live being. The less changes in mortality rate is due to hypertensive disorders in pregnancy. Conclusion: The methodology has been used could be adopted in other investigations to distinguish and measuring effect of predictive factors on the risk of an outcome
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