Decrease In Intensity Research Articles

Effects of bird feather-like convergent–divergent-riblet surfaces on the total pressure loss and wake turbulence of a transonic compressor cascade

The flow loss caused by the fan blades in a turbofan engine with a large bypass ratio is significant, and the wake considerably affects the inlet flow of downstream components. Surfaces with bird feather-like convergent–divergent (C–D) riblets have been proven to modulate the boundary layer flow by inducing counter-rotating rolling modes; however, the effects of these surfaces on the total pressure loss and wake turbulence of transonic compressor cascades remain unexplored. In this study, the effects of C–D-riblet surfaces on the total pressure loss and wake turbulence of a transonic compressor cascade were experimentally investigated using a five-hole probe and hot-wire measurements. The flow-loss-control effects of C–D-riblet surfaces with different characteristic lengths were also analyzed. The most significant reduction in the area-averaged total pressure loss (11.23%) was achieved using a C–D-riblet surface with a characteristic length of 30 μm at a Mach number of 0.94; this total pressure loss reduction corresponded to an increase in the mean velocity and a decrease in the turbulence intensity of the wake profile. Furthermore, the effectiveness of the loss control varied significantly with the spreading position of the C–D riblets. The optimal control effect was observed in the divergence-line region, and the control was slightly less effective as the measurement position neared the convergence line. This paper demonstrates the promising potential of using C–D riblets to achieve flow loss control in transonic compressor cascades.

Global Analysis of the Extended Decreases in Cosmic Rays Observed with Worldwide Networks of Neutron Monitors and Muon Detectors: Temporal Variation of the Rigidity Spectrum and Its Implication

This paper presents the global analysis of two extended decreases in the galactic cosmic-ray intensity observed by worldwide networks of ground-based detectors in 2012. This analysis is capable of separately deriving the cosmic-ray density (or omnidirectional intensity) and anisotropy, each as a function of time and rigidity. A simple diffusion model along the spiral field line between Earth and a cosmic-ray barrier indicates the long duration of these events, resulting from about 190° eastern extent of a barrier such as an interplanetary shock followed by the sheath region and/or the corotating interaction region (CIR). It is suggested that the coronal mass ejection merging with and compressing the preexisting CIR at its flank can produce such an extended barrier. The derived rigidity spectra of the density and anisotropy both vary in time during each event period. In particular we find that the temporal feature of the “phantom Forbush decrease (FD)” reported in an analyzed period is dependent on rigidity, and looks quite different at different rigidities. From these rigidity spectra of the density and anisotropy, we derive the rigidity spectrum of the average parallel mean free path of pitch angle scattering along the spiral field line and infer the power spectrum of the magnetic fluctuation and its temporal variation. The possible physical cause of the strong rigidity dependence of the phantom FD is also discussed. These results demonstrate the high-energy cosmic rays observed at Earth responding to remote space weather.

A fluorescence biosensor for organophosphorus pesticide detection with a portable fluorescence device-based smartphone

An innovative fluorescence biosensor was successfully developed to detect organophosphorus pesticide (OPs) by utilizing smartphone technology. The assay relied on the enzymatic activity of alkaline phosphatase (ALP), which facilitated the conversion of L-ascorbic acid 2-phosphate sesquimagnesium salt hydrate (AAP) into L-ascorbic acid (AA). The AA that generated was then reactedwith o-phenylenediamine (OPD) to yield a fluorescent marker identified as 3-(1,2-dihydroxyethyl)furo[3,4-b]quinoxalin-1(3H)-one (DFQ). A novel bandpass approach was specifically developed for a smartphone that was integrated with a customized portable fluorescence device to measure the fluorescence emission of DFQ. The device has a unique application that converts the fluorescence intensity into an RGB signal. In the presence of OPs, malathion was chosen as the representative of the OPs substance; the enzymatic activity of the ALP was inhibited, resulting in a decrease in fluorescence intensity, which was proportional to the concentration of malathion. Smartphones can be used to measure fluorescence emission, offering a calibration sensitivity more than 70 times higher than that of conventional spectrofluorometer. The recently developed methodology can be employed to identify malathion within the concentration range of 0.1–1 ppm, with a detection limit of 0.05 ppm. The practical applicability of the method was established using vegetable samples, and the acquired results were in good agreement with those obtained using the standard HPLC approach. This innovative method provides both portability and accuracy, while also exhibiting a notable degree of sensitivity in detecting traceamounts of OPs.

Exploring the interaction between derivatives of urea with resorcinol-based acridinedione dyes by employing fluorescence methods and molecular docking approach

Akyl urea derivatives, either symmetrical or unsymmetrical in nature possessing a free N-H or N-alkyl moieties in the molecular framework of urea governs the excited state properties of acridinedione dye (ADR1) which is a resorcinol-based derivative. Fluorescence enhancement (FE) of ADR1 dye is observed on the addition of unsymmetrical urea derivatives, whereas a decrease in the fluorescence intensity resulted upon the addition of symmetrical urea derivatives. The nature of the urea derivatives controls the suppression of photoinduced electron transfer (PET) via space, which is the cause of the FE. FQ results from the donor and acceptor moieties of ADR1 dye promoting the PET process. Urea (U), symmetrical and unsymmetrical urea derivatives (except Tetramethyl urea (TMU)) results no significant shift of the localized excited (LE) state emission of ADR1 dye. Studies of the ADR1 dye’s fluorescence lifetime in the presence of urea compounds show a significant increase in lifetime. This phenomenon is explained by a significant difference in the hydrogen-bonding (HB) pattern, which causes variationin the microenvironment created by thesolute molecules in the aqueous phase. Both the hydrophobic effects of the alkyl group substituents in the urea molecular framework and the HB interactions between the solute and solvent influence the excited state features of ADR1 dye. Further, the role of urea derivatives and ADR1 dye (both are considered as competitive guest molecules) energetics and molecular interactions were studied in the presence of host molecule, Human Serum Albumin (HSA). The binding energy (BE) and several bimolecular interactions driven by urea derivatives in the presence of ADR1-HSA complex in comparison with that of urea derivatives-HSA complex were investigated by molecular docking (Mol.Doc) methodology. Incorporating theoretical research along withsteady state and time-resolved fluorescence investigations proved to be an effective method to evaluate the interactions of competing solutes comprising bothhydrophobic and HB functional groups.

Evaluation of nature-based climate solutions for agricultural landscapes in the Galápagos Islands

The Galápagos Islands are highly vulnerable to climate and environmental change, and nature-based solutions can help local communities adapt local agricultural systems. Through a comparative analysis, we evaluated the effects of three land management strategies on soil temperature, soil water availability and storage, and carbon stocks in Santa Cruz Island (Galápagos Archipelago). We installed six monitoring sites that consisted of two replicates per pathway: (i) the avoided loss of tropical forest, (ii) the conservation of scattered trees and living fences in at-risk agroforestry system, and (iii) the increase in biomass after a reduction of the grazing intensity. The monitoring sites were equipped with a dense network of rain gauges, air temperature and relative humidity sensors, and capacitance/frequency probes that registered volumetric water content and soil temperature. After pedological characterization of the soil profiles, the soil physico-chemical and hydrophysical properties were determined in laboratory. Over a period of 30 months (July 2019 to December 2021), hydrometeorological and soil environmental data were collected.We assessed differences in soil temperature, moisture availability and soil organic carbon content between native forests, sites under traditional agroforestry and under passive restoration. Forest soils were 12 % cooler;, and soil moisture under forest was 20 % higher than in parcels with silvopastural management. Forest soils had a lower dry bulk density, lower saturated hydraulic conductivity and higher water retention capacity in comparison with the other two management types. In silvopastural systems, a decrease of grazing intensity had a positive effect on soil carbon stocks, that were about 50 % higher than in soils under traditional management. This study shows that avoided loss of tropical forest within an agricultural landscape is a promising strategy to mitigate increasing soil temperatures, agricultural drought, and decline in soil organic carbon content. Continued monitoring of the experimental sites is necessary to corroborate the findings of this investigation at longer temporal scales.

Neural correlates of systemic lidocaine administration in healthy adults measured by functional MRI: a single arm open label study.

Intravenous lidocaine is increasingly used as a nonopioid analgesic, but how it acts in the brain is incompletely understood. We conducted a functional MRI study of pain response, resting connectivity, and cognitive task performance in volunteers to elucidate the effects of lidocaine at the brain-systems level. We enrolled 27 adults (age 22-55 yr) in this single-arm, open-label study. Pain response task and resting-state functional MRI scans at 3 T were obtained at baseline and then with a constant effect-site concentration of lidocaine. Electric nerve stimulation, titrated in advance to 7/10 intensity, was used for the pain task (five times every 10 s). Group-level differences in pain task-evoked responses (primary outcome, focused on the insula) and in resting connectivity were compared between baseline and lidocaine conditions, using adjusted P<0.05 to account for multiple comparisons. Pain ratings and performance on a brief battery of computer-based tasks were also recorded. Lidocaine infusion was associated with decreased pain-evoked responses in the insula (left: Z=3.6, P<0.001, right: Z=3.6, P=0.004) and other brain areas including the cingulate gyrus, thalamus, and primary sensory cortex. Resting-state connectivity showed significant diffuse reductions in both region-to-region and global connectivity measures with lidocaine. Small decreases in pain intensity and unpleasantness and worse memory performance were also seen with lidocaine. Lidocaine was associated with broad reductions in functional MRI response to acute pain and modulated whole-brain functional connectivity, predominantly decreasing long-range connectivity. This was accompanied by small but significant decreases in pain perception and memory performance. NCT05501600.

Response of submarine braided channels to varying inflow hydrographs: Geomorphic experiments and stratigraphic implications

AbstractSubmarine channels on the seafloor experience a range of turbidity current‐flood hydrographs. The characteristics of the flood hydrograph influence channel dimensions, the number of channel threads (i.e. braiding intensity) and the depositional properties of sandbars within the channels. However, the morphodynamic response of submarine braided channels to different hydrograph patterns is poorly understood. In this study, six geomorphic experiments are used to test how varied flood hydrographs affect the braiding intensity and sandbar geometry within submarine channels. Three experiments represent the control group with constant density‐current inflow, and three experiments use different time‐varying hydrograph patterns. The experiments show that, as the inflow‐to‐sediment discharge ratio increases, multiple small channels coalesce into a few main channels, causing a decrease in active braiding intensity defined by the channel threads with flow. When the flow returns to the initial low flow rate, active braiding intensity increases again. These observations show that the inflow‐to‐sediment discharge ratio determines the value of active braiding intensity. Additionally, active braiding intensity is directly proportional to dimensionless sediment‐stream power and dimensionless stream power, in agreement with previously established trends for both submarine and fluvial braided channels. In contrast to active braiding intensity changes, the measured sandbar aspect ratio and compactness ratio (i.e. ratio of planform area to perimeter) of submarine braided channels is insensitive to changes in the hydrograph. However, when inflows reach peak discharge, the higher transport capacity erodes pre‐existing deposits, forming noticeable erosional surfaces, and subsequently depositing thicker sandbars during that stage. These observations imply that sandbar planform morphology is largely insensitive to hydrograph, but hydrograph variability induces a greater variability in the resultant stratigraphic packages. The experimental results predict that field‐scale stratigraphy should be dominated by strata deposited during intervals of high flow, but that these strata will also exhibit reduced lateral continuity compared to formation scenarios with constant discharge.

Analysis of land use changes and soil erosion using the EPM-IntErO model in the Sokobanja Basin, Serbia

Soil erosion, with the progressive loss of fertile topsoil and its negative impact on agricultural productivity, has become a critical global environmental problem. In the second half of the 20th century, many municipalities in Serbia experienced significant changes in land use, vegetation, and environmental conditions. The drive towards industrialization and urbanization aimed to improve the living standards of the population, but as a consequence, it led to substantial depopulation of rural areas and the adoption of inadequate agricultural practices, which, in turn, further intensified soil erosion. This study focuses on the Sokobanjska Moravica River basin (Eastern Serbia), extending to the Bovan Lake Dam and upstream, with a total area of 540.4 km². The basin is situated in a characteristic karst landscape. Changes in erosion intensity and runoff from this basin are analyzed using the Intensity of Erosion and Outflow (IntErO) model, which algorithmically integrates the widely used Erosion Potential Method (EPM) with innovative computational techniques to predict sediment production and runoff from the river basin accurately. This analysis utilizes GIS software and official statistical yearbook data, focusing on the period from the second half of the 20th century, including the analysis of the current state. According to our research, the most intensive changes in land use occurred between 1961 and 1971, marking the beginning of the period of a decline in rural population and, consequently, a decrease in erosion intensity. Key findings indicate that predominant changes in land use and vegetation led to a shift from crop farming to animal husbandry. After 1971, ongoing depopulation, particularly in rural areas, resulted in a gradual and steady decrease in erosion intensity. The primary aim of this study is to support policymakers in developing more effective soil and water conservation regulations. By making recommendations for the protection of vegetation, and thus the soil within this river basin, this research helps ensure their long-term preservation. Future research should focus on the long-term impacts of current land use practices and develop strategies to mitigate erosion in the context of changing climate conditions.

Numerical Simulation of Spectral Radiation for Hypersonic Vehicles

The spectral radiation of hypersonic vehicles and surrounding flow fields is crucial for optical target detection. A novel approach combines Low-Discrepancy Sequences with the Reverse Monte Carlo Method to simulate the spectral radiation of hypersonic missiles. The effects of chemical non-equilibrium reactions and high-emissivity coating failures on the spectral radiation of a typical biconical hypersonic missile were investigated. Significant differences were found among chemical equilibrium, non-equilibrium, non-reactive, and catalytic wall models. High-emissivity coating failures occur mainly in the high-temperature regions of the nose cone and fins. The non-equilibrium model shows a transition peak distribution of NO in the head shock layer within the ultraviolet gamma band, with integrated ultraviolet radiation (200–300 nm) three times higher than the equilibrium model. In the 1–3 μm band, the non-equilibrium model’s radiation intensity at a 120° horizontal detection angle is about 1.46 times that of the equilibrium model. Using real coating emissivity, the 3–5 μm band radiation intensity is about 5% higher, and the 8–14 μm band is about 8.51% lower than the uniform emissivity model. When high-emissivity coating emissivity fails by 40%, the 3–5 μm band intensity decreases by about 15.38%, and the 8–14 μm band intensity decreases by about 12.67%.

An unusual triplet population pathway in the Reaction Centre of the Chlorophyll-d binding Photosystem I of A. marina, as revealed by a combination of TR-EPR and ODMR spectroscopies

Photo-induced Chlorophyll (Chl) triplet states in the isolated Photosystem I (PSI) of Acaryochloris marina, that harbours Chl d as its main pigment, were investigated by Optically Detected Magnetic Resonance (ODMR) and Time-Resolved Electron Paramagnetic Resonance (TR-EPR), and as a function of pre-illumination of the sample under reducing redox poising. Fluorescence Detected Magnetic Resonance (FDMR) allowed resolving four Chl d triplet (3Chl d) populations (T1-T4) both in untreated and illuminated samples in the presence of ascorbate and N,N,N′,N′-tetramethyl-p-phenylenediamine (TMPD). The FDMR signals increased following the pre-illumination treatment, particularly for the T3 and T4 populations, which are therefore sensitive to the redox state of PSI cofactors. Microwave-induced Triplet minus Singlet (TmS) spectra were detected in the |D|-|E| resonance window of the T3 and T4 triplets. These showed a broad singlet bleaching centred at 740 nm and also displayed complex spectral structure with several derivative-like features, indicating that both the T3 and T43Chl d populations are associated with the PSI reaction centre (RC) triplet, P3740. Parallel measurements by TR-EPR demonstrated that triplet signals observed under all conditions investigated are dominated by an electron spin polarisation (esp), which is typical of intersystem crossing, differently from what expected for recombination triplet states formed from a radical pair precursor. Moreover, stronger reductant conditions obtained by pre-illumination of the samples in the presence of dithionite and 5-methylphenazinium methyl sulfate (PMS) did not lead to a recombination triplet state esp, but rather to a decrease of the whole signal intensity. The energetics of A. marina PSI and the possible occurrence of distributions of cofactors redox properties are discussed in order to address the unexpected P3740 esp.

Colorimetric approach based on iron oxide magnetic molecularly imprinted nanozyme for sensitive determination of antipyrine and benzocaine: Application to environmental water samples and pharmaceutical dosage form

Nanozymes provide the required enzymatic activity however, they lack the selectivity to target a certain drug during analysis. Herein, a novel polydopamine molecularly imprinted polymer (MIP) was fabricated onto Fe3O4 nanozymes surface for sensitive and selective determination of antipyrine (ANT) and benzocaine HCl (BEN). Synthesized Fe3O4 nanozyme with peroxidase like activity catalyzed the oxidation of ortho phenylenediamine by the aid of H2O2 to produce intense yellow color that can be measured via colorimetric assay. The MIPs were prepared and characterized using field-emission scanning electronic microscopy, Fourier-transform IR spectroscopy, surface area analysis, and X-ray diffraction spectrum. Two Fe3O4 @ MIP NPs nanozyme with peroxidase like activity of two drugs were prepared. Upon binding of the target drug with its respective MIP, an inhibition in the Fe3O4 enzymatic activity occurred and thus a decrease in the yellow color produced. This quantitative decrease in the color intensity represents the drug concentration. Factors affecting the enzymatic colorimetric reaction have been investigated and optimized. The formed MIPs increased the sensitivity of the proposed method with LOD 1.405, 0.658 ng mL−1, LOQ 4.259, 1.993 and recovery percentage of 100.07, 100.57 for ANT and BEN, respectively. The reusability of the Fe3O4 @ MIP NPs was assessed for six cycles without significant loss in enzymatic oxidase activity. Furthermore, the method was validated following ICH guidelines. Then, it was successfully applied for determination of the two drugs in spiked environmental water samples and pharmaceutical formulation.

From molecules to materials: SHG-CD microscopy of structured chiral films

The interplay between molecular and structural chirality as a function of local sample morphology determines the nonlinear optical properties of many organic and hybrid organic–inorganic thin films. Here, we used second harmonic generation circular dichroism (SHG-CD) microscopy of thin molecular films of 1,1′-bi-2-naphthol (R-BINOL) as a research model. Our results show that the SHG signal measured at frequencies close to the electronic transition of BINOL molecules is resonantly enhanced by more than an order of magnitude compared to the non-resonant case. The extracted resonant SHG-CD signal is dominated by the chiral response of the molecule. In contrast, structural chirality determines the non-resonant SHG-CD images. We see clear evidence that the interference of the SHG signals caused by the molecular and structural chirality can lead to a decrease in the overall SHG intensity when both SHG signals are out of phase. These findings highlight the intricate relationship between molecular and structural chirality on the one hand and structural morphology on the other hand and pave the way for novel applications by exploiting the chiroptic properties of thin films.

Unveiling the Multi-Targeted Mode of Action: Investigating the Antiepileptic Activity of Murraya koengii Extract in PTZ-induced Seizures.

Recurrent seizures are the hallmark of the neurological condition known as epilepsy. Murraya koenigii (curry leaves) has been traditionally used in medicine for various ailments. This study aimed at the anticonvulsant activity of HAEMK using a petylenetetrazole (PTZ) induced seizure model. Behavioral and biochemical parameters were assessed to determine the effectiveness of the extract in mitigating seizures. Albino mice were orally administered with different doses of the extract prior to PTZ administration. The behavioral parameters, including seizure latency, duration and severity, were monitored and recorded. Additionally, acetylcholine esterase, GSH, and malondialdehyde (MDA), three indicators of oxidative stress, were assessed in brain tissue homogenates. HAEMK-treated groups demonstrated a substantial increase in seizure latency and a decrease in seizure length and intensity compared to the control group. A dose-dependent MDA and acetylcholine esterase decreased concurrent GSH rise were seen in the HA-treated groups. These findings suggest that the hydroalcoholic extract of M. koenigii possesses antiepileptic activity, possibly mediated through its antioxidative mechanisms.

Application of multiple dynamic sensory techniques to N-lauroyl amino acids: Exposing the relationship between taste-enhancing properties and chemical structure

This study investigated the taste enhancing effects of N-lauroyl amino acids, including N-lauroyl-phenylalanine, N-lauroyl-tryptophan and N-lauroyl-tyrosine. Sensory results obtained through TDS, TCATA, and TI assessments indicated that all N-Lau-AAs significantly increased the umami intensity and duration of solutions such as simulated chicken broth. Moreover, these compounds masked bitter taste, with LTR showing the most pronounced reduction of bitterness. LP had the effect of enhancing saltiness, whereas LTR and LTY diminished saltiness. Structural analysis revealed a correlation between the chemical structure of N-Lau-AAs and their sensory properties. The presence of carbon‑carbon double bond (CC) was positively correlated with umami intensity and negatively correlated with bitter and salty parameters. Phenolic hydroxyl groups (OH) were negatively correlated with umami intensity and positively correlated with a decrease in bitterness intensity and duration. Overall, this study provides valuable insights into the taste enhancement potential of N-Lau-AAs as taste enhancers in the food industry.

ProDiVis: a method to normalize fluorescence signal localization in 3D specimens.

A common problem in confocal microscopy is the decrease in intensity of excitation light and emission signal from fluorophores as they travel through 3D specimens, resulting in decreased signal detected as a function of depth. Here, we report a visualization program compatible with widely used fluorophores in cell biology to facilitate image interpretation of differential protein disposition in 3D specimens. Glioblastoma cell clusters were fluorescently labeled for mitochondrial complex I (COXI), P2X7 receptor (P2X7R), β-Actin, Ki-67, and DAPI. Each cell cluster was imaged using a laser scanning confocal microscope. We observed up to ∼70% loss in fluorescence signal across the depth in Z-stacks. This progressive underrepresentation of fluorescence intensity as the focal plane deepens hinders an accurate representation of signal location within a 3D structure. To address these challenges, we developed ProDiVis: a program that adjusts apparent fluorescent signals by normalizing one fluorescent signal to a reference signal at each focal plane. ProDiVis serves as a free and accessible, unbiased visualization tool to use in conjunction with fluorescence microscopy images and imaging software.

Silica nanodots: Luminescent effects and insights for the determination of catecholamines

The effect of various catecholamines on the luminescent properties of silica nanodots (SiNDs) was studied and the new method using SiNDs that represent a promising green alternative to other analytical techniques for the determination of catecholamines has been developed. A change in spectral properties of SiNDs in the presence of catecholamines occurs, depending on the nature of the substance. Dopamine causes a decrease in the luminescence intensity of SiNDs at 445 nm whereas in the presence of norepinephrine and epinephrine a maximum appears in the luminescence spectrum of SiNDs at 500 and 510 nm, respectively. The intensity at 445 nm or the ratio of the intensities at 500 (510) nm and 445 nm can be used as analytical signals for the determination of the corresponding catecholamines. Limits of detection for dopamine, norepinephrine and epinephrine are 2, 0.06, and 0.14 µM, respectively.

Technical evaluation of supercritical fluid impregnation scaling-up of olive leaf extract: From lab to pilot scale

Supercritical fluid technology is an advanced field that offers remarkable versatility and it applies to a broad range of processes. However, the scaling-up of the supercritical fluid impregnation process is still scarcely explored. This research investigates the technical analysis of the supercritical fluid impregnation scaling-up of olive (Olea europaea L.) leaf extract into polypropylene (PP) films. The impregnation scale was increased up to 20-fold while maintaining constant ratios among the extract volume, film area, CO2 amount, and vessel geometry. The study compares homogeneity, total extract loading, and ABTS antioxidant activity of impregnated films at both scales. Homogeneity was assessed using CIELAB coordinates and desorption electrospray ionization mass spectroscopy (DESI-MS) imaging. Films impregnated at 250 bar and 55 °C for 1 h in 100 ml and 500 ml vessels were uniform in colour, whereas those from the larger vessel were less homogeneous. To evaluate the effect of time on impregnation at the largest scale, impregnation was conducted for 1, 6, 24, and 48 h. Homogeneity and ABTS antioxidant activity improved over time, and DESI-MS images showed a gradual decrease in oleuropein signal intensity over time. After 6 h, PP films achieved a total extract loading of 14.02 mg g−1 of polymer, 23 % ABTS antioxidant activity, with a global diffusion coefficient of the extract compounds in PP films of 3.42 × 10−13 m2 s−1. While this study offers valuable insights into scaling up the supercritical fluid impregnation of olive leaf extract into PP films, several limitations remain. Future research is required for a more comprehensive understanding and practical application of the process.

Au/ZnO nanocomposites based on simple laser ablation method for water treatment

A binary heterostructure of Au/ZnO nanocomposite is prepared in a novel way based on successive pulsed laser ablation of the two targets in an aqueous solution with varied pulse time. The development of the method allows generating a noble metal (Au) and metal oxide (ZnO) one after one to produce a novel heterostructure with a tunable shell applicable as a catalytic degradable material. The nanocomposite samples are tested to study their optical, morphological, and structural properties. The photocatalytic degradation study demonstrates a significant decrease in the absorbance intensity of Rohdamin B (RhB) dye as the irradiation time increases. It indicates a reduction in dye concentration with a remarkable improvement in contact time. Besides, the degradation percentage against pH value is investigated. It reveals an increasing trend as the pH value rises with a maximum percentage at pH 10. The study is also concerned with the influence of the initial concentration of RhB dye on the degradation efficiency of the nanocomposite. Higher initial concentrations of the dye lead to a decrease in the degradation efficiency of the catalysts. Finally, the kinetic analysis of RhB photodegradation reveals that the Langmuir-Hinshelwood first-order kinetic model accurately describes RhB's adsorption onto the nanocomposites.

Win by Hook or Crook? Self-Injecting Favorable Online Reviews to Fight Adjacent Rivals

Literature has long assumed that unethical behaviors are fueled by competition. This study challenges this prevailing notion by introducing a conceptual distinction between rivalry and competition. We show that rivalry-induced deterrence triggers the formation of mutual forbearance in self-injecting favorable reviews. Mutual forbearance collapses when one party unilaterally engages in self-injecting behaviors, prompting the other party to retaliate by increasing their self-injecting activities. The presence of an additional rival leads to a 3.2% decrease in self-injecting intensity. Furthermore, self-injecting intensity increases by 0.095% for every 1% rise in that of the rivals and increases by 0.041% for a 1% rise in that of the nonrival competitors. Given the apparent role of rivalry in reducing self-injecting behaviors, platforms should strategically consider how system designs and policies can cultivate firms’ feelings of rivalry and avoid non-rival competition. We recommend platforms consider including evaluations from peer hotels as an alternative index for recommending hotels to potential consumers. Introducing peer evaluations to the current online review systems could attenuate the bias of consumer ratings and facilitate the formation of rivalry, which hinders self-injecting behaviors.

A Stochastic FRET Study on the Core Dimension of Polystyrene-block-Poly(Polyethylene Glycol Monomethyl Ether Acrylate) Micelles.

Polystyrene-b-poly(polyethylene glycol monomethyl ether acrylate) (PSt-b-PPEGA) copolymers featuring pyrene and perylene as the Förster resonance energy transfer (FRET) donor (denoted as D-BCP) and acceptor (denoted as A-BCP), respectively, were synthesized via the reversible addition and fragmentation chain transfer (RAFT) polymerization. These copolymers were then used to form DA-mixed micelles via a dialysis method. The micelles consisted of D-BCP (mole fraction fD = 0.04), A-BCP (fA = 0.04), and label-free PSt-b-PPEGA (fN = 0.92). The decrease in fluorescence intensity of pyrene in the micelles confirmed the occurrence of FRET, with an observed efficiency of 0.32. A Monte Carlo approach was employed to estimate the expected FRET efficiency, assuming the random fractional distribution of D-BCP and A-BCP, along with the random spatial distribution of pyrene and perylene within the micellar core. The observed FRET efficiency suggested a core radius (Rc) of 0.95R0, where R0 was the Förster critical distance. With R0 calculated to be 3.2 nm based on Förster theory, Rc was determined to be approximately 3.0 nm, aligning closely with the dried-out core radius estimated from aggregation number and polystyrene density. This stochastic FRET methodology was further applied to investigate the swelling behavior of the polymer micelles in a mixture of N,N-dimethylformamide (DMF) and water. Dynamic light scattering analysis revealed minimal change in core dimension below 60 vol % DMF content. However, FRET analysis provided a deeper insight, showing an increase in core radius with DMF content up to 20 vol %, followed by saturation up to 50 vol %, offering a more comprehensive understanding of the micelle swelling behavior.