17315 research outputs found
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Microwave-tuned Mn-doped ZnO for all-in-one supercapacitors: correlating defect chemistry with electrochemical behavior
Full text linkZinc oxide-based (ZnO) electrode materials have emerged as contenders for heightened cost efficiency, fast charge-discharge prowess, outstanding performance metrics, and remarkable cycle stability in supercapacitor technologies. Among the myriad synthesis techniques, the microwave-assisted approach distinguishes itself with an array of advantages, being time-efficient, eco-friendly, and adept at providing accurate control over the complex ZnO morphology. Introducing ions like [Figure presented] into the ZnO lattice further propels the electrochemical performance of supercapacitors into superior territories. Hence, this investigation meticulously prepared a series of undoped and Mn-doped ZnO materials utilizing a microwave-assisted synthesis method across four different microwave powers ranging from 160 to 800 W. Cutting-edge morpho-structural characterization techniques, including X-ray diffraction, scanning electron microscopy, electron paramagnetic resonance, photoluminescence, and Raman spectroscopy, were employed to delve into the structure and defect centers of the ZnO-based samples. It has been conclusively demonstrated that the concentration of [Figure presented] is pivotal, offering additional charge carriers without compromising the crystallinity of ZnO while also enhancing diffusion correlated with Faradaic redox reactions—thereby escalating the supercapacitor's properties. A doping concentration of 2% Mn-ions balances charge carriers with structural integrity. This sample achieved a specific capacitance of 340 F/g, a power density of 59.7 kW/kg, and an energy density of 47.1 Wh/kg. Across the board, all samples demonstrate impressive stability, retaining over 70% capacity after 5000 charge-discharge cycles. Notably, ZnO with 2% Mn synthesized at 160 W excels with over 90% capacitance retention. This distinct behavior is attributed to the transformative influence of Mn ion doping on ZnO's structural and morphological attributes
Child temperament and sleep problems: the moderating role of bedtime routines
No full textBackground: Children’s temperamental traits, such as rhythmicity, reactivity, and persistence, as well as bedtime routines, play a crucial role in influencing their sleep behaviors. Objective: The present study examined the contributions of the children’s temperament (rhythmicity, reactivity, and persistence) and bedtime routines to children’s sleep problems, with a further interest in examining the moderating role of bedtime routines between child temperament and sleep problems. Method: The sample consisted of 313 mothers of children aged between 16 and 84 months (M = 52.42, SD = 12.36). The mothers provided reports on their children’s sleep problems, bedtime routines, and temperament. Results: Hierarchical regression analyses were run to test hypotheses. Results indicated that children’s temperamental rhythmicity and reactivity were closely linked to sleep problems, with bedtime routines, especially a consistent bedtime environment, helping to reduce these issues. Consistent bedtime practices moderated the effect of low rhythmicity, as children with lower rhythmicity experienced fewer sleep problems when routines were stable. Conclusions: Regular bedtime routines may serve as a protective factor, mitigating the effects of challenging temperamental traits on sleep
Changes and continuities in intergenerational fathering in Türkiye
No full textThis qualitative study examined intergenerational transmission of fathering in Türkiye, a Majority World context, with particular attention to the socioeconomic status (SES) characteristics. In exploring the intergenerational transmission of fathering in Türkiye, this study was informed by Greenfield's social change theories (2009, 2016) and Kağıtçıbaşı's family change theories (2007, 2012), both of which emphasise the impact of major demographic shifts in family dynamics. This study employs a qualitative research design, drawing on interviews with 29 Turkish fathers (aged 28 to 44) of young children. Thematic analysis of the interviews revealed that being a moral guide was a consistently upheld fathering role, predominantly endorsed by fathers from lower SES families. In contrast, autonomy support and open expression of affection were two sustained parenting practices that were more pronounced among non-low SES fathers. A small subset of fathers sustained negative parenting practices such as being overly restrictive, permissive, or indifferent. Compared to their own fathers, contemporary Turkish fathers are adopting a more communicative, engaged, and supportive fathering style, with this trend being particularly evident among non-low SES fathers. These changes and continuities in fathering were analysed and discussed in relation to various mechanisms and expectations of fatherhood across different SES groups
Gender inequality and cultural values in explaining gender differences in positive and negative emotions: a comparison of 24 countries during the COVID-19 pandemic
No full textThe coronavirus pandemic posed a major challenge to mental health. Existing evidence shows that COVID-19 is related to poor emotional well-being, particularly among women. However, most work on the subject uses single-country samples, limiting the ability to generalize the disparity or explain it as a function of societal variables. The present study investigates the expression of positive and negative emotions during the pandemic as a function of gender and across 24 countries (N = 49,637). Strong gender differences emerged across countries, with women reporting more negative emotions (anxious, depressed, nervous, exhausted) and less positive emotions (calm, content, relaxed, energetic) than men. The gender gap in positive emotions was significantly wider in countries higher in individualism and narrower in countries higher in power distance. For instance, differences in emotions were larger in Western countries high in individualism, such as the USA, the UK, Italy, and France, and smaller in countries with higher collectivism and power distance, such as China, Malaysia, and South Korea, with a few exceptions like Japan and Brazil. These gender differences across countries were not explained by country-level gender inequalities indicators (GGGI and GII). Interestingly, the national severity of the pandemic, an epidemiological factor, reduced gender differences in positive emotions. These results underscore the importance of considering cultural and national factors when assessing gender differences in well-being
Assessment of stiffness-dependent autophagosome formation and apoptosis in embryonal rhabdomyosarcoma tumor cells
No full textRemodeling of the extracellular matrix (ECM) eventually causes the stiffening of tumors and changes to the microenvironment. The stiffening alters the biological processes in cancer cells due to altered signaling through cell surface receptors. Autophagy, a key catabolic process in normal and cancer cells, is thought to be involved in mechano-transduction and the level of autophagy is probably stiffness-dependent. Here, we provide a methodology to study the effect of matrix stiffness on autophagy in embryonal rhabdomyosarcoma cells. To mimic stiffness, we seeded cells on GelMA hydrogel matrices with defined stiffness and evaluated autophagy-related endpoints. We also evaluated autophagy-dependent pathways, apoptosis, and cell viability. Specifically, we utilized immunocytochemistry and confocal microscopy to track autophagosome formation through LC3 lipidation. This approach suggests that the use of GelMA hydrogels with defined stiffness represents a novel method to evaluate the role of autophagy in embryonal rhabdomyosarcoma and other cancer cells
On the effects of 3D printed mold material, curing temperature, and duration on polydimethylsiloxane (PDMS) curing characteristics for lab-on-a-chip applications
No full textSoft lithography with microfabricated molds is a widely used manufacturing method. Recent advancements in 3D printing technologies have enabled microscale feature resolution, providing a promising alternative for mold fabrication. It is well established that the curing of PDMS is influenced by parameters such as temperature, time, and curing agent ratio. This study was conducted to address inconsistencies in PDMS curing observed when using different 3D-printed mold materials during the development of a Lab-on-a-Chip (LoC) system, which is typically employed for investigating the effect of hydrodynamic cavitation on blood clot disintegration. To evaluate the impact of mold material on PDMS curing behavior, PDMS was cast into molds made from polylactic acid (PLA), polyethylene terephthalate (PET), resin, and aluminum, and cured at controlled temperatures (55, 65, and 75 °C) for various durations (2, 6, and 12 h). Curing performance was assessed using Soxhlet extraction, Young’s modulus calculations derived from Atomic Force Microscopy (AFM), and complementary characterization methods. The results indicate that the mold material significantly affects PDMS curing kinetics due to differences in thermal conductivity and surface interactions. Notably, at 65 °C, PDMS cured in aluminum molds had a higher Young’s modulus (~1.84 MPa) compared to PLA (~1.23 MPa) and PET (~1.17 MPa), demonstrating that the mold material can be leveraged to tailor the mechanical properties. These effects were especially pronounced at lower curing temperatures, where PLA and PET molds offered better control over PDMS elasticity, making them suitable for applications requiring flexible LoC devices. Based on these findings, 3D-printed PLA molds show strong potential for PDMS-based microdevice fabrication
Hydrophilic monomer and crosslinker effects on optical and chemical properties of hydrophobic intraocular lenses (IOLs)
Full text linkAn experimental study was conducted to reduce glistening and minimize posterior capsule opacification (PCO) in hydrophobic intraocular lenses (IOLs). This approach involved the copolymerization of hydrophilic 2-hydroxyethyl acrylate (HEA) at various concentrations with hydrophobic monomers, along with incorporating different amounts of ethylene glycol di-methacrylate (EGDMA) as a crosslinker to optimize the chemical, thermal, and optical properties. Sixteen IOL formulations were synthesized and systematically analyzed using equilibrium water content (EWC) measurements, glass-transition temperature (Tg) measurements, and optical evaluation. Optimizing the balance of hydrophilic monomer and crosslinker effectively eliminates glistening and mitigates PCO while maintaining the essential optical property of hydrophobic IOLs
Extraction and applications of frankincense oleoresin as functional ingredient in pectin/sodium-alginate composite films for active packaging
Full text linkThe composite films fabricated by incorporating frankincense oleoresin (FOR) into pectin and sodium alginate matrices, were underwent several analysis including thickness, mechanical strength, barrier properties, color attributes, morphological structure, surface roughness, chemical composition, crystalline nature, as well as evaluations of antioxidant and antimicrobial properties. The findings of the study indicated an increase in the thickness of the film samples with the addition of FOR however reduction in both tensile strength (from 9.59 to 2.58 MPa) and elongation at break (from 9.85 % to 3.22 %) was observed. The water vapor permeability of the developed films demonstrated an increase from 0.411 to 0.878 (g∗mm)/(m2∗h∗kPa). Atomic Force Microscopy (AFM) imaging results indicated a reduction in the surface roughness of films upon the addition of FOR. Additionally, Fourier Transform Infrared Spectroscopy (FTIR) spectra unveiled chemical interactions between the film-forming polymers and FOR. Furthermore, a significant enhancement in the antioxidant activity was observed in films incorporating FOR, compared to the control group. These FOR-loaded film samples demonstrated antimicrobial effects against Pseudomonas aeruginosa, while no inhibitory zones were observed against Staphylococcus aureus and Candida albicans. In summary, the outcomes of this investigation highlight the promising potential of pectin/sodium alginate composite films containing FOR in packaging applications
Developing immunoniosomes (INs): antibody and fab conjugations of niosomal nanoparticles via UV-NBS and EDC/NHS chemistry for treating glioblastoma cells
Full text linkAntibody-conjugated nanoparticles (ACNPs), particularly immunoliposomes (ILs), have gained significant attention in cancer treatment due to their enhanced efficacy and superior tissue penetration. However, their high production costs and technical challenges underscore the need for more cost-effective alternatives. Niosomes, with their lower production costs, improved stability, and biocompatibility, have emerged as promising alternatives to liposomes in drug delivery. This study introduces immunoniosomes (INs), a novel class of antibody-conjugated niosomes, through two conjugation strategies: (i) UV-NBS, a site-specific covalent conjugation method utilizing an indole ring structure for moderate binding to the variable regions of antibodies and Fab fragments, and (ii) EDC/NHS chemistry, which conjugates antibodies to carboxylated niosomes via primary amines on lysine sidechains. Bevacizumab, a monoclonal antibody targeting VEGF and approved for the treatment of various cancers including glioblastoma multiforme (GBM), was used as a model therapeutic. Both Bevacizumab and its Fab fragment were conjugated to niosomes and evaluated in U87 glioma cells (overexpressing VEGF) and human umbilical vein endothelial cells (HUVECs) (representing normal VEGF expression). Physicochemical characterization of the conjugated niosomes confirmed hydrodynamic sizes ranging from 100 to 200 nm, neutral surface charge, and dispersity indices below 0.5—properties critical for effective cellular penetration and drug delivery. Cellular toxicity assays, conducted at a 10× dilution from commonly reported concentrations, highlighted the role of the autocrine loop in U87 glioblastoma cells. Importantly, specific Nio-Fab conjugate formulations, created through both site-specific and randomized conjugation strategies, exhibited enhanced cytotoxicity toward U87 cells while sparing healthy endothelial HUVEC cells. In summary, this research establishes novel conjugation strategies to produce stable, site-specific, and randomized antibody-niosomal conjugates with enhanced half-life and selective toxicity against GBM cells. By offering an alternative route for antibody delivery through niosomal nanocarriers, these findings open new avenues for the development of more effective GBM therapeutics, warranting further non-clinical and clinical investigations
Detailed time-resolved spectral and temporal investigations of SGR J1550-5418 bursts detected with fermi gamma-ray burst monitor
Full text linkWe have conducted a time-resolved spectral analysis of magnetar bursts originating from SGR J1550−5418. Our analysis utilizes a two-step methodology for temporal segmentation of the data. We first generated and fitted overlapping time segments. Subsequently, we obtained nonoverlapping time segments with varying lengths based on their spectral evolution patterns, employing a machine learning algorithm called k-means clustering. For the fitting process, we employed three distinct models, namely a modified blackbody (MBB-RCS), a double blackbody (BB+BB), and a power law with an exponential cutoff (COMPT) model. We found that nearly all of the time segments fit well with the COMPT model. Both the average peak energy in the νFν spectra (Epeak) and photon index parameters follow a Gaussian distribution with means ∼30 keV and −0.5, respectively. Furthermore, there is a strong positive correlation between the cooler and hotter temperature parameters of the BB+BB model, and both parameters show a Gaussian distribution with peaks ∼4 and 12 keV, respectively. Additionally, we found that the distribution of the temperature parameter of the MBB-RCS model can be fit with a skewed Gaussian function with a peak ∼9-10 keV. Lastly, we searched for quasiperiodic spectral oscillations (QPSOs) in the hardness ratio evolution of the bursts. We identified five potential QPSO candidates at frequencies ranging from ∼15 to ∼68 Hz. We discuss and compare these results with previous studies