Sensitive Reaction Research Articles

Underground nuclear astrophysics: Status and recent results from Felsenkeller laboratory

For almost three decades it has been known that the study of astro-physically important nuclear reactions between stable nuclei requires the use of low-background, underground accelerator laboratories. The Felsenkeller shallow-underground laboratory in Dresden, shielded by a 45 m thick rock cover, hosts a 5 MV Pelletron ion accelerator with an external sputter ion source (mainly able to provide carbon and oxygen beams) and an internal radio-frequency ion source (providing proton and alpha beams). The reduced muon, neutron and gamma-ray background achieved both with natural and active shielding situate the laboratory well in line with deep underground accelerator labs worldwide and allows highly sensitive nuclear reaction experiments. Currently, measurements affecting the solar fusion and Big Bang nucleosynthesis are ongoing. In addition to in-house research by HZDR and TU Dresden, the lab is an open facility for scientific users worldwide, with beam time applications reviewed by an independent science advisory board. Furthermore, EU-supported transnational access is available via the ChETEC- INFRA network for nuclear astrophysics. A brief introduction to underground nuclear astrophysics, status of the Felsenkeller shallow-underground laboratory and some preliminary results are discussed.

Covert, Grandiose, and Dysfunctional Subtype of Narcissistic Personality Disorder

Abstract Narcissistic personality disorder(NPD) is described in the DSM-IV-TR as “a pervasive pattern of grandiosity, need for admiration and lack of empathy.” The other features are: grandiose sense of self-importance and grandiose fantasies, belief in being special and unique, need for admiring attention, sense of entitlement, exploitation, arrogance, lack of empathy, and envy of others or belief that others envy them. Other features are: vulnerable self-esteem; feelings of shame, sensitivity and intense reactions of humiliation, emptiness or disdain to criticism or defeat; and vocational irregularities resulting from difficulties tolerating criticism or competition. Hence, NPD should be understood from the context of grandiosity and self esteem dysregulation. The subtypes of NPD i.e. the shy, covert, besides the arrogant, overt, grandiose and unempathetic helps emphasise the phenomenologic range of narcissism. We report a case of narcissistic personality disorder, who presented with the unusual subtype with shyness, covertness, poor functioning, but grandiose.

Nitric oxide releasing novel amino acid-derived polymeric nanotherapeutic with anti-inflammatory properties for rapid wound tissue regeneration.

Endogenous gasotransmitter nitric oxide (NO) is a central signalling molecule that modulates wound healing by maintaining homeostasis, collagen formation, wound contraction, anti-microbial action and accelerating tissue regeneration. The optimum delivery of NO using nanoparticles (NPs) is clinically challenging; hence, it is drawing significant attention in wound healing. Herein, a novel polymeric nanoplatform loaded with sodium nitroprusside (SP) NPs was prepared and used for wound healing to obtain the sustained release of NO in therapeutic quantities. SP NPs-induced excellent proliferation (∼300%) of mouse fibroblast (L929) cells was observed. With an increase in the SP NPs dose at 200 μg mL-1 concentration, a 200% upsurge in proliferation was observed along with enhanced migration, and only 17.09 h were required to fill the 50% gap compared to 37.85 h required by the control group. Further, SP NPs showed an insignificant impact on the coagulation cascade, revealing safe wound-healing treatment when tested in isolated rat RBCs. Additionally, SP NPs exhibited excellent angiogenic activity at a 10 μg mL-1 dose. Moreover, the formulated SP nanoformulation is non-irritant, non-toxic, and does not produce any skin sensitivity reaction on the rat's skin. Further, an in vivo wound healing study revealed that within 11 days of treatment with SP nanoformulation, 99.2 ± 1.0% of the wound was closed, while in the control group, only 45.5 ± 3.8% was repaired. These results indicate that owing to sustained NO release, the SP NP and SP nanoformulations are paramount with enormous clinical potential for the regeneration of wound tissues.

Practical potential of suspension electrodes for enhanced limiting currents in electrochemical CO2 reduction.

CO2 conversion is an important part of the transition towards clean fuels and chemicals. However, low solubility of CO2 in water and its slow diffusion cause mass transfer limitations in aqueous electrochemical CO2 reduction. This significantly limits the partial current densities towards any desired CO2-reduction product. We propose using flowable suspension electrodes to spread the current over a larger volume and alleviate mass transfer limitations, which could allow high partial current densities for CO2 conversion even in aqueous environments. To identify the requirements for a well-performing suspension electrode, we use a transmission line model to simulate the local electric and ionic current distributions throughout a channel and show that the electrocatalysis is best distributed over the catholyte volume when the electric, ionic and charge transfer resistances are balanced. In addition, we used electrochemical impedance spectroscopy to measure the different resistance contributions and correlated the results with rheology measurements to show that particle size and shape impact the ever-present trade-off between conductivity and flowability. We combine the modelling and experimental results to evaluate which carbon type is most suitable for use in a suspension electrode for CO2 reduction, and predict a good reaction distribution throughout activated carbon and carbon black suspensions. Finally, we tested several suspension electrodes in a CO2 electrolyzer. Even though mass transport limitations should be reduced, the CO partial current densities are capped at 2.8 mA cm-2, which may be due to engineering limitations. We conclude that using suspension electrodes is challenging for sensitive reactions like CO2 reduction, and may be more suitable for use in other electrochemical conversion reactions suffering from mass transfer limitations that are less affected by competing reactions and contaminations.

Effects of radiative heat loss on extinction limits of counterflow premixed ammonia-air flames

The effect of radiative heat loss on counterflow premixed ammonia-air flames has been investigated as a function of equivalence ratio and system pressure. Non-adiabatic counterflow premixed flame simulations incorporating detailed chemistry, transport, and radiative heat transfer in the optically thin limit have been employed to elucidate important underlying physics and extinction characteristics. Similar to methane-air flame systems, non-adiabatic counterflow premixed computations show that the combined effects of positive flame stretch, sub-unity Lewis number, and radiative heat loss lead to the extension of the lean flammability limit for ammonia-air flames, revealing a C-shaped curve near the lean flammability limit that exhibits both radiation-induced and stretch-induced extinction states. The computations compare favorably with the experimentally determined extinction stretch rate values for the stretch-induced extinction states over a wide range of equivalence ratios at different pressures up to 5 atm. A novel feature sensitivity analysis has also been developed to highlight important sensitive reactions for the stretch- and radiation-induced extinction states. Furthermore, the controlling chemistry at the dual-extinction states and at varying pressures are compared and discussed.

Macrophage-mediated mechanisms of lung injury in the sensitization reaction to Echinococcus granulosus.

In this study, the impact of inhibiting the PI3K/AKT/NF-κB pathway on lung oxidative damage induced by Echinococcus granulosus cyst fluid was investigated. Twenty-four mice were randomly assigned to four groups. Three months after inoculation with hydatid cyst segments, mice in group A were treated with intraperitoneal and intratracheal saline injections; mice in group B were administered a caudal vein injection of a PI3K inhibitor, followed by cyst fluid sensitization; mice in group C received an AKT inhibitor via caudal vein, followed by cyst fluid sensitization; and mice in group D were subjected to cyst fluid sensitization without any inhibitor treatment. Cellular changes in lung tissues across all groups were evaluated, including pathological section analysis. Analysis of pulmonary tissue and serum from these mice included the assessment of PI3K/AKT/NF-κB pathway proteins, inflammatory factors, and related mRNA levels. Mice in groups B and C exhibited a higher proportion of M2-type macrophages and significantly lower levels of PI3K/AKT/NF-κB pathway proteins, inflammatory factors (interleukin-6 [IL-6]/tumor necrosis factor-α [TNF-α]), and oxidative markers in lung tissues compared to mice in group D (P < 0.05). Our results in this study indicate that activation of the PI3K/AKT/NF-κB pathway contributed to an increase in the M1 macrophage phenotype, leading to enhanced secretion of peroxidases and inflammatory factors. This mechanism plays a crucial role in the oxidative and inflammatory lung damage associated with allergic reactions to E. granulosus cyst fluid.

Revealing the low to moderate temperature oxidation kinetics of 1,2,4-trimethylbenzene sensitized by dimethyl ether

Low to moderate temperature oxidation has been a vital topic in the combustion chemistry due to its critical role in controlling the combustion characteristics such as autoignition and pollutant emissions. Low temperature oxidation kinetics of alkanes and oxygenated biofuels have been widely explored, while that of branched aromatics is poorly understood. This work aims to investigate the low to moderate temperature oxidation kinetics of 1,2,4-trimethylbenzene (TMB, C9H12), which is a multi-branched alkylbenzene with weak low temperature oxidation reactivity. To enhance the low temperature oxidation reactivity of TMB, dimethyl ether (DME) was added to efficiently provide chain initiators. The oxidation experiment of TMB/DME mixture was performed with an atmospheric jet stirred reactor coupled with synchrotron vacuum ultraviolet radiation photoionization mass spectrometry. The negative temperature coefficient (NTC) behavior, as well as featured aromatic intermediates, especially phenyl hydroperoxides and unexpected highly oxygenated molecules (HOMs), were observed in the experiment. The detection of these fingerprint aromatic intermediates provide crucial evidence for revealing the low to moderate oxidation kinetics of TMB. In addition, a kinetic model was developed to provide in-depth kinetic analysis. The results demonstrate that the active chain initiators produced from DME oxidation trigger the low temperature chain-branching reactions of TMB. The chain recycling process is further sustained due to the regeneration of active intermediates such as phenyl hydroperoxides and •OH radicals. Aromatic intermediates with chemical compositions of C9H12Ox and C9H10Ox were measured and identified to be key indicators for the low temperature chemistry of TMB. In particular, the aromatic HOMs (C9H12O6 and C9H10O5) are fingerprint intermediates produced from the third O2 addition and subsequent reactions of TMB. Besides, the sensitivity analysis indicates that the interaction kinetics between TMB and DME by sharing the highly sensitive reactions of hydroperoxides and •OH radicals. The present work extends the conceptual reaction schemes proposed in alkanes towards branched aromatics, especially sequential O2 addition reactions that contributing to the formation of phenyl hydroperoxides and HOMs.

A revised reaction kinetic mechanism for the oxidation of methyl formate

The combustion kinetics of methyl formate (MeFo), a promising oxygenated, highly knock-resistant e-fuel, is investigated in this work. The potential energy surfaces (PESs) of the low-temperature oxidation reactions of MeFo radicals were determined at the CCSD(T)-F12/cc-pVTZ-F12//B2PLYP-D3/cc-pVTZ level of theory and their rate coefficients were obtained with RRKM/master equation. The thermochemical properties of relevant intermediate species were calculated by using the G4 method. A chemical mechanism for the oxidation of MeFo was developed by adding fuel-specific reactions taken from a literature model into a well-validated base mechanism, and incorporating the newly calculated rate constants of elementary reactions and thermochemical properties of species. The fuel-specific mechanism was further revised in terms of reaction channels and rate coefficients for improved prediction accuracy. In particular, the O2 addition to hydroperoxy radicals (QOOH), the isomerization of peroxy hydroperoxy radicals (OOQOOH), the subsequent ketohydroperoxide (KET) decomposition, and the formally direct pathways of MeFo radicals (R) with O2 were added for the completeness of consumption pathways, in conjunction with the reaction channels of alkoxy radicals (RO) and hydroperoxides (ROOH). For good model prediction accuracy of ignition delay times, especially in the high-temperature range, the resulting mechanism was optimized by modifying the rate constants of several important H-atom abstraction reactions of MeFo within their uncertainty limits. The performance of the proposed mechanism is demonstrated through extensive validation against literature data obtained from different experimental configurations. Finally, the underlying reaction pathways of MeFo are explored by means of reaction flux analysis with the newly developed chemical mechanism.Novelty and significance statement: This work proposes a new reaction kinetic mechanism for the oxidation of methyl formate. Quantum chemistry calculation at high level of theory was performed to explore the low-temperature chemistry of MeFo. The reaction mechanism was improved by including missing reaction channels, incorporating theoretically calculated rate and thermochemical data, and modifying rate constants of sensitive reactions. The mechanism has been validated successfully against extensive data available in the literature covering a wide range of conditions and facilities. By using this new mechanism, reaction pathway analysis is performed to provide insights into the oxidation chemistry of MeFo.

DAYA PROTEKSI LOTION DENGAN MINYAK ATSIRI SERAI DAPUR (Cymbopogon citratus) TERHADAP NYAMUK Aedes aegypti

Lemongrass consists of two types that have many benefits. Its use in research or in processing using its stems alone causes lemongrass leaf waste which can be used as an essential oil and used as an anti-mosquito lotion to reduce the use of chemicals as repellent. The purpose of this study was to determine the yield of lemongrass essential oil, to determine the protective power of each concentration of citronella essential oil in lotion in repelling mosquito bites, and to determine the level of preference for mosquito repellent lotion. The average yield with three repetitions followed by standard deviation (SD) was 0.1% ± 0.0024% b/b. Lotion preparation provides different protection during 6 hours of exposure, namely K- and F1 no protection, F2 for 2 hours, F3 and K+ 4 hours and F4 5 hours. Based on all parameters, the most preferred formulation is F1 and does not give sensitive reactions. Keyword: Aedes aegypti, essential oils, lemongrass, lotions.

Functions and semantics of foreign language beauty vocabulary in the modern Russian language

The authors examine the main principles of the vocabulary of the semantic field “Cosmetics and cosmetic products” formation and development in the modern Russian language. The purpose of this study is to describe the functional status and semantic parameters of lexical units of foreign origin in comparison with their prototypes. The relevance of the work is dual: extralinguistic space transformation, the deepening of knowledge about it and the complication of the knowledge structure means the evolution of language systems, where the vocabulary demonstrates the most sensitive reactions and, therefore, higher dynamics. The material of the work included the data form advertising texts and audiovisual documents published in specialized magazines (articles and reviews), as well as users’ comments at beauty forums. The authors followed the system-synergetic model of foreign lexemes in the Russian language compared with their prototypes in the source language. The concept of language contacts is clarified and the main approaches to the typology of foreign vocabulary are provided. The authors establish the most significant differential semes that categorize the vocabulary of the sphere under study and clarify its etymological composition. The types of variability of foreign language units in the beauty vocabulary are described in detail and the wide distribution of these particular variants are explained. Based on a detailed structural analysis of lexical units, the authors draw conclusions about the productivity of some morphological ways of forming new words, such as suffixation and composition. The study also reveals the increasing frequency of the so-called phraseological (or combinability) calquing. A comparative component analysis of the meaning of a foreign word in Russian and its prototype identified ascending trends in semantics within the framework of the studied layer: the functioning of semantic rows where logical-hierarchical paradigms are built.

Effects of dimethyl ether blending on H2-fueled combustion characteristics and thermal improvement in fuel-lean condition

Micro-combustors play a pivotal role in micro powering system due to the potential for high energy density. However, addressing challenges such as incomplete combustion and high heat dissipation losses are essential for optimizing the working performance. So, the blended DME is proposed to micro-combustion, which acts as a promising oxygenated fuel with significant attention due to its higher reactivity, lower pollutant emissions, and carbon–neutral properties. However, the lack of dynamic models applicable to H2/DME fueled combustion in micro condition, so an optimized mechanism for blended H2/DME combustion is developed and validated. The results demonstrate that a reduced mechanism comprising 29 species and 106 reactions (M29-106*) can be commendably employed in micro H2/DME/air combustion simulation, according to the sensitivity analysis and reaction modification. Besides, investigation is conducted to explore micro-combustion characteristics of H2/DME/Air. The result shows that burning process and heat transfer are notably influenced by DME addition, leading to shifts in flame positions and adjustments in combustion reaction rates. So, DME addition enhances energy efficiency and modifies flame location through fluid field optimization and reduced heat loss. The thermal performance of the combustor is significantly improved with DME blending, resulting in higher radiative power and radiation efficiency. However, the choice of DME blending ratio must be carefully considered, as high blending ratios may compromise flame stability and lead to increased exhaust heat losses under fuel-lean conditions. Specifically, burning with 30 % DME addition achieves a radiative power of 20.24 W and a radiative efficiency of 40.57 % at the same chemical energy Ec = 49.9 W, which is 5.57 W and 11.17 % higher than that of pure H2-fueled combustion, respectively. These findings offer valuable insights for the design and optimization of micro-combustors, where compact and efficient power sources are required.

Structural dependent degradation of histamine H2-receptor antagonists by UV/NH2Cl: Reactive species contribution and the role of carbonate ions on ·NO generation

Histamine H2-receptor antagonists (HRAs) are a group of widely used gastrointestinal drugs that have been frequently detected in natural environments. UV/chloramine (NH2Cl) is a widely used disinfection process in water treatment, while the performance of HRAs degradation by UV/NH2Cl is still unclear. In this work, the degradation kinetics, mechanism and disinfection byproducts formation of HRAs by UV/NH2Cl were studied. The degradation of HRAs, including ranitidine (RNTD), nizatidine (NZTD), roxatidine (RXTD), cimetidine (CMTD) and famotidine (FMTD) was fast in the UV/NH2Cl process, and ·OH, Cl· and ·NO contributed to their degradation. CMTD had the highest rate constants with ·OH, Cl· and ·NO. RXTD, NZTD and FMTD were more reactive with ·OH, while RNTD was more selective towards Cl·. The contribution of ·OH, Cl· and reactive nitrogen species to HRAs degradation in water matrices was further quantified by kinetic modeling. Interestingly, carbonate species were found to promote the yield of ·NO. Further investigation through sensitivity analysis of the modeling reactions concluded the sensitive reactions for ·NO promotion. The structure–activity assessment domenstrated that the reactivity of thioether sulfur, CMTD-C3 and RXTD-N48 and piperidine rings resulted in the difference of degradation rates. Hydroxylation, nitrosation, chlorine substitution and oxygen atom transfer were the primary pathways for HRAs degradation. The formation of NDMA might be a prevalent problem along HRAs’ degradation in the UV/NH2Cl process, and the formation potential of NDMA is dependent on the types of amine groups in HRAs. This work provides an effective strategy to eliminate HRAs, revealed the NDMA formation potential in HRAs, and emphasized the role of carbonate species in ·NO generation.

Inhibition of hydrogen-air mixtures by using chemical vapor additives

Various approaches are being used for the minimization of risk related to hydrogen hazards. The present study highlights the suppression of hydrogen-air explosion using additives (bromoethane and bromopropane) through experimental and theoretical methods. The experiments were carried out with different equivalence ratios (Ф = 0.5–2) and additive contents (3–15%) at 298 K and 1 bar initial conditions. The results indicate the influence of additives on the maximum pressure-rise, minimum ignition energy and burning velocity. Theoretical study was conducted using CHEMKIN and determined the sensitivity analysis, species profile and reaction path analysis. After the explosion, pressure increases at lower additive fractions for fuel-lean and stoichiometric mixtures and decreases at higher additive contents. In fuel-rich mixtures, pressure rapidly decreases with the increasing additive contents. In the presence of additives, the relative pressure-rise rate decreases, while the time to maximum pressure-rise and ignition energy increase are irrespective of Ф. Moreover, the maximum declination of burning velocity reflects at Φ = 2 and 3% of either additive reduces the burning rate almost by half. The sensitivity coefficient decreases for the flame-promoting reactions and increases for the flame-inhibiting reactions. In such reactions, the inhibiting radicals capture the free radicals and cease the flame propagation, resulting in flame suppression. The reactions R788 (C2H5Br + OH = C2H4Br + H2O) and R834 (C3H7Br + OH = C3H6Br + H2O) have a negative reaction sensitivity coefficient that reflects the effect of suppression. The enhancement of the mole fraction of hydrogen bromide (HBr) with additive content signifies flame suppression. The effect of additives on the explosion characteristics indicates that bromopropane is more effective than bromoethane in minimizing hydrogen hazards.

High Heart Rate Variability Causes Better Adaptation to the Impact of Geomagnetic Storms

Our study aimed to test whether specific sensitive reactions in healthy males to the changes in geomagnetic activity (GMA) are different depending on the baseline self-regulation of the autonomic nervous system (ANS). In this study, the ANS response in the different phases of geomagnetic storms (GMSs) has been measured via the heart rate variability (HRV) using one-way ANOVA and the Bonferroni-adjusted t-test. In the case of high HRV, changes were found to indicate a significant intensification of both parts of the ANS: the sympathetic part (SP) showed increased stress levels and the parasympathetic part (PP) marked a self-regulation effort in the main and restoration phases of GMSs. In the case of low HRV, changes indicate a significant enhancement in the SP after the main phase of GMSs, with a day’s delay. GMA is a sufficient environmental factor for healthy males, causing stress reactions of the ANS in the main and restoration phases of GMSs. However, the different self-regulation of the ANS results in different dynamics in its variation depending on the individual’s character of the baseline ANS state; the optimal adaptation reactions of healthy males with baseline high HRV are achieved with decreased heart rate and increased HRV in the main phase of GMSs.

Setting Safe Operation Conditions for Acetyl Chloride Hydrolysis through Dynamic Modelling and Bifurcation Analysis

Acetyl chloride hydrolysis is a highly sensitive exothermic reaction that has presented several industrial safety issues. In the present study, a multiparameter mathematical model, previously developed and applied to simulate the oscillatory thermal behavior of an experimental continuous stirred tank reactor, was used to determine the static/dynamic bifurcation behavior of this reactive system. The values predicted by the model showed good agreement with the experimental data reported in the literature. Full topological classification of its fixed points and iterative maps was obtained: unique solutions (stable and unstable), multiple solutions, cyclic envelope, and bifurcation objects of codimension 1 (e.g., fold and Hopf’s points) and codimension 2 (e.g., cusp and generalized Hopf and Bogdanov-Takens points) have been uncovered. The emphasis of the analysis is to determine safe operating conditions through understanding these topological features and manipulating the reactor design and operating parameters.

Moringa oleifera Leaves Protein Enhances Intestinal Permeability by Activating TLR4 Upstream Signaling and Disrupting Tight Junctions.

Changes in intestinal mucosal barrier permeability lead to antigen sensitization and mast cell-mediated allergic reactions, which are considered to play important roles in the occurrence and development of food allergies. It has been suggested that protein causes increased intestinal permeability via mast cell degranulation, and we investigated the effect of camellia Moringa oleifera leaves protein on intestinal permeability and explored its role in the development of food allergies. The current study investigated the effect of M. oleifera leaves protein on intestinal permeability through assessments of transepithelial electrical resistance (TEER) and transmembrane transport of FITC-dextran by Caco-2 cells. The expression levels of Toll-like receptor 4 (TLR4), IL-8, Occludin, Claudin-1, and perimembrane protein family (ZO-1) were detected by real-time PCR and Western blotting. The effect of M. oleifera leaves protein on intestinal permeability was verified in mice in vivo. The serum fluorescence intensity was measured using the FITC-dextran tracer method, and the expression of tight junction proteins was detected using Western blotting. The results showed that M. oleifera leaves protein widened the gaps between Caco-2 cells, reduced transmembrane resistance, and increased permeability. This protein also reduced the mRNA and protein levels of Occludin, Claudin-1, and ZO-1. Animal experiments showed that intestinal permeability was increased, and that the expression of the tight junction proteins Occludin and Claudin-1 were downregulated in mice. This study shows that M. oleifera leaves protein has components that increase intestinal permeability, decrease tight junction protein expression, promote transmembrane transport in Caco-2 cells, and increase intestinal permeability in experimental animals. The finding that M. oleifera leaves active protein increases intestinal permeability suggests that this protein may be valuable for the prevention, diagnosis, and treatment of M. oleifera leaves allergy.

Fillers Around the Nose.

The aim of this paper is to review the fillers around the nose. The literature search was performed at the PubMed and Proquest Central database of the Kirikkale University Library. Characteristics of an ideal dermal filling material would be low cost, high safety, not causing pain during filling, provoking few sensitivity reactions and being durable. The material should allow reproducible results that are in line with expectation and produce a natural texture, be quick to use, be operation-ready, not cause the patient to need to convalesce and rarely cause complications. Nasal contour remodeling using fillers has several advantages: there is a brief recovery period, a general anesthetic is not needed and ecchymosis does not occur. There are a lot of filler materials, such as collagen, hyaluronic acid, Polymethylmethacrylate with Bovine Collagen, Poly-L-Lactic Acid, calcium hydroxylapatite and expanded polytetrafluoroethylene. It is absolutely essential to choose carefully appropriate material and procedure for patients to obtain optimum results.

Dual-mode fluorescence and colorimetric sensing of sulfide anion in natural water based on near-infrared Ag2S quantum dots and MnO2 nanosheets complex

Near infrared (NIR) emission Ag2S quantum dots (QDs) are of great value for biochemical sensing with strong anti-interference and low toxicity. Herein, NIR fluorescence Ag2S QDs were synthesized successfully. Combined with the excellent oxidase-like characteristics of manganese dioxide (MnO2) nanosheets, a fluorescence and colorimetric dual-mode sensor for sulfide anion was developed. MnO2 nanosheets could effectively catalyze the oxidation of TMB to produce blue TMB oxide (ox TMB), at the same time, the fluorescence of Ag2S QDs could be effectively quenched by fluorescence internal filtration effect (IFE) and dynamic quenching effect. The enzyme-like activity was weakened and the NIR fluorescence of Ag2S QDs was restored when sulfide anion (S2−) was added, due to the reduction of MnO2 to Mn2+.The linear ranges for fluorescence and colorimetric analysis of S2− were 2–250 μM and 0.3–50 μM, with detection limits of 0.6 and 0.215 μM, correspondingly. The dual-mode sensor had a wider detection range, higher sensitivity and shorter reaction time, which could be used for highly selective detection of S2− in different concentration ranges. In addition, it had been successfully applied to the determination of sulfide in water samples with satisfactory accuracy and sensitivity.

Impact of Tinted Lenses on Contrast Sensitivity, Color Vision, and Visual Reaction Time in Young Adults

Impact of Tinted Lenses on Contrast Sensitivity, Color Vision, and Visual Reaction Time in Young Adults

Impact of dopant X in zirconia on carbon deposition at the Nickel/X-stabilized zirconia(XSZ) surface in dry CH4 and CH4/H2O environments: First-principles density functional theory calculation and experimental study

The impact of a dopant (X; X = Y or Sc) in zirconia on carbon deposition in CH4 and CH4/H2O environments was studied experimentally and via first-principles calculations. In the CH4 environment, the apparent activation energy for the carbon deposition of Ni/ScSZ was lower than that of Ni/YSZ. SEM/EDS observation indicated the Ni/XSZ interface was key to elucidating the dopant-induced difference. To clarify the difference, the calculation presented two mechanisms: first, the vacancy in ScSZ rather than that in YSZ was readily moved to a neighboring site, thereby stabilizing the vacancy configuration after CH–CH bonding. Second, Ni was readily distorted in Ni/ScSZ at the specific vacancy configuration, thereby decreasing the forward activation energy. In CH4/H2O environment, the calculation showed larger dopant Y caused steric hindrance to prevent CH + O→CHO which was the sensitive reaction in the steam reforming. This explained lower reforming rate in Ni/YSZ than in Ni/ScSZ.