Filtering Effect Research Articles

Redox interference-free bimodal paraoxon sensing enabled by an aggregation-induced emission nanozyme catalytically hydrolyzing phosphoesters specifically

In view of the current serious situation of organophosphorus pesticides (OPs) residue contamination, developing rapid and accurate OPs sensors is a matter of urgency. Redox-nanozyme based colorimetric sensors have been widely researched and utilized in OPs residue determination, but overcoming the interference of external redox substances and the effect of single-signal modes on detection performance is still a challenge. Here we fabricated a Zr-based metal–organic framework (MOF) featuring specific phosphatase-like activity and strong aggregation-induced emission (AIE) fluorescence for redox interference-free bimodal pesticide sensing. In the MOF, the activity-tunable Zr4+ node offered high hydrolytic activity and affinity toward P–O containing substrates, and the rigid framework structure effectively enhanced the fluorescence emission of the ligand 1,1,2,2-tetra(4-carboxylphenyl)ethylene. The developed AIEzyme could efficiently catalyze the hydrolysis of paraoxon to yellow p-nitrophenol, which further reduced the intrinsic AIE fluorescence of AIEzyme through internal filtration effect. Thereby, a natural enzyme-free dual-mode colorimetric/fluorescence approach was established for paraoxon detection with no interference from redox substances, and a smartphone-assisted portable platform was further developed to enable the facile, rapid, and high-performance sensing of the pesticide in complex practical matrices.

Effect of Cow Urine and Culture Filtrates of Trichoderma isolate S-13 on Fungal Pathogens of Basmati Rice

Rice (Oryza sativa L.) is the principle food crop for majority population of the world. Basmati rice is a unique crop of Himalaya comprising good quality characters and aroma. Basmati rice is being infected by numerous diseases. To manage these diseases, fungicides being used for years. This leads to the residual effects of fungicides on grains and soils so there is needs for alternate approaches to the manage disease. Hence use of cow urine and Trichoderma isolate S-13 is considered as the sustainable approach for management of important diseases of basmati rice. In this study we used different concentration of cow urine, Trichoderma isolate S-13, and Propiconazole (control check) against brown spot and bakanae disease of rice. Among these the maximum mycelial inhibition observed in Trichoderma isolate S-13 @15per cent (66.33per cent) followed by cow urine @15per cent (52.59 per cent). In Bakanae disease the maximum inhibition observed in Trichoderma isolate S-13 @ 15per cent (58.89 per cent) followed by cow urine@15per cent (49.26 per cent).

Fluorescence/colorimetric dual-signal sensor based on carbon dots and gold nanoparticles for visual quantification of Cr3.

A convenient and sensitive dual-signal visualization method is constructed for detection of trivalent chromium ions (Cr3+) based on fluorescent carbon dots (CDs) and glutathione-modified gold nanoparticles (GSH-Au NPs). The fluorescence of CDs can be quenched by GSH-Au NPs due to the inner filter effect. Cr3+ induces aggregation of GSH-Au NPs because of the coordination with GSH on the surface of Au NPs, leading to the red shift of surface plasmon resonance absorption of Au NPs that provides a "turn-on" fluorescence and colorimetric assay for Cr3+. The fluorescence/colorimetric dual signal detection shows high sensitivity for Cr3+ with wide detection linear ranges (0.5-70μM for fluorescence detection and 2-50μM for colorimetric detection) and low detection limits (0.31μM for fluorescence detection and 0.30μM for colorimetric detection). Besides, the method has high selectivity for Cr3+ and can be used for detection of Cr3+ in lake water and tap water samples, showing great potential for visual detection of environmental Cr3+.

Generation and Editing of 2D Shapes using a Branched Representation

In this paper we propose a new planar shape representation, the medial branch graph representation (MBGR) which allows to easily generate, vary and edit all-new sorts of parametric shapes. Each MBGR shape is described by a collection of connected control circles organized as a graph. Each pair of connected circles generates a branch of the shape. The boundaries of the branches are designed using cubic Bézier curves which enable shape representation in a compact SVG format. Each circle is associated with a regularity parameter locally controlling the smoothness of the branch connections. In this way, we can manage shapes having both sharp corners and smooth boundaries. To illustrate the potential of the MBGR representation we have created an online facility ( https://mbgrg.github.io/mbgrg/ ) where the user can create/edit MBGR shapes automatically or interactively.

Experimental study of the effects of a particle filter in front of automotive radiator on its cooling performances and cooling drag

According to the World Health Organization (WHO), air pollution is the single greatest worldwide health risk especially in urban environments. In these areas, the vehicle traffic significantly contributes to the fine dust concentration in the ambient air. While the current legislation focuses mainly on the exhaust emission of vehicles, 85% of the overall fine dust emissions originating from brakes, tires, and road abrasion are not yet regulated. In this context, an integrated particulate filter system fitted into previously unused installation spaces in frontend of a vehicle in front of the radiator allows to compensate a part of the particle emissions of a vehicle try to reach the neutral emission. Add filter is not without consequences for the cooling performances. This study aims to assess the impact of the particulate filter system on the radiator cooling performances and cooling drag coefficient. An experimental setup was developed to characterize an automotive radiator with and without particle filter in terms of power and velocity distribution. Cooling capacity of the radiator depends clearly of the airflow through the radiator. Filter increases the pressure drop and decreases airflow. Hence, the heat power exchange can be reduced up to 10% for a pressure drop level almost twice. The airflow inlet inside engine compartment is not beneficial for aerodynamic aspect. By increasing pressure drop, the cooling drag coefficient can be reduced up to 10% when a filter covers entirely the radiator surface. The results indicate that the filter affects the cooling capacity of the radiator, which can require modifications to the cooling system strategy.

Multi-sensor possibility PHD filter for space situational awareness

Tracking multiple space objects using multiple surveillance sensors is a critical approach in many Space Situation Awareness (SSA) applications. In this process, the uncertainties of targets, dynamics, and observations are usually represented by the probability distributions. However, precise characterization of uncertainty becomes challenging due to imperfect knowledge about some key aspects, such as birth targets and sensor detection profiles. To overcome this challenge, this paper proposes a multi-sensor possibility PHD filter based on the theory of outer probability measures. An effective compensation method is introduced to tackle variations in the fields of view of SSA sensors or instances of missed detections, aiming to mitigate the inconsistency in localized information. The proposed method is adapted to centralized and distributed sensor networks, offering effective solutions for multi-sensor multi-target tracking. The major innovation of the proposed method compared with typical methods is the proper description of epistemic uncertainty, which yields more robust performance in the scenarios of lacking some information about the system. The effectiveness of the multi-sensor possibility PHD filter is demonstrated by a comparison with conventional methods in two simulated scenarios.

Effect of impact kinematic filters on brain strain responses in contact sports.

Impact kinematics are widely employed to investigate mechanisms of traumatic brain injury (TBI). However, they are susceptible to noise and artefacts; thus, require data filtering. Few studies have focused on how data filtering affects brain strain most relevant to TBI. Here, we report that impact-induced brain strains are much less sensitive to data filtering than kinematics based on three filtering methods: CFC180, lowpass 200Hz, and a new method called Head Exposure to Acceleration Database in Sport (HEADSport). Using mouthguard-measured head impacts in elite rugby (N=5694), average Euclidean distances between the three filtered angular velocity profiles and their unfiltered counterparts are used to identify three groups of impacts with large variations: 90-95th, 95-99th, and >99th percentile. From each group, 20 impacts are randomly selected for simulation using the anisotropic Worcester Head Injury Model (WHIM) V1.0. HEADSport and CFC180 are the most and least effective, respectively, in suppressing "unphysical artefacts" shown as sharp spikes with a rather short impulse duration (e.g., <3 ms) in angular velocity. However, maximum principal strain (MPS), especially that in the corpus callosum, is much less sensitive to data filtering compared to kinematic peaks (e.g., reduction of 3% vs. 47% and 90% for peak angular velocity and acceleration with HEADSport for impacts of >99th percentile). These findings confirm that the brain acts as a low-pass filter, itself, to suppress high frequency noise in impact kinematics. Therefore, brain strain can serve as a common metric for TBI biomechanical studies to maximize relevance to the injury, as it is not sensitive to kinematic filters.

THE EFFECT OF BLUE LIGHT BLOCKING SPECTACLES LENSES FOR DIGITAL ASTHENOPIA

This systematic review evaluated the impact of blue-blocking (BB) spectacle lenses on digital asthenopia, considering 9 relevant studies published in the last de­cade. While two studies indicated some effectiveness of BB lenses in reducing symptoms like eye pain and heavy eyes, others did not show significant differences compa­red to no-block (NB) lenses in various eye strain symp­toms. Overall, the evidence lacks conclusive support for the effectiveness of BB filters in alleviating digital eye strain (DES) symptoms, emphasizing the need for more standardized and comprehensive research in this area.

Preparation and application of DES doped carbon quantum dots for fluorescent chromium ions determination

ABSTRACT This paper uses orange peel and deep eutectic solvents as precursors to prepare DES-CQDs via one-step hydrothermal method. The average size of DES-CQDs is 5.5 nm, with abundant luminescent groups such as amino and hydroxyl groups on the surface. Under the excitation of ultraviolet light at 360 nm, blue fluorescence with a wavelength of 452 nm is emitted. In addition, to investigate the practical application effect of DES-CQDs, this study further used DES-CQDs as fluorescent sensor to detect Cr6+ ions in solutions. The results showed that Cr6+ exhibited a significant quenching effect on DES-CQDs, consistent with the quenching mechanism of static quenching and internal filtering effect, and the limit of detection was 3.2 nM. The recovery rates of Cr6+ spiked in four environmental samples are 94.27 ~ 100.51%, indicating that DES-CQDs can be used for the detection of Cr6+ in complex environmental samples.

Grouting characteristic in rock fractures with different structural properties: Apparatus design and experimental study

Rock fracture surfaces are normally rough, with upper and lower surfaces presenting obvious structural properties (i.e., matching or mismatching). In this paper, rock fracture was divided into shear and tensile fractures based on its mechanical origin. A test simulation system for grouting in rough fracture (tensile and shear fractures) with continuous pressure field monitoring was proposed. A series of grouting simulation tests were employed to evaluate the effect of fracture structural property, fracture surface roughness, and aperture on the characteristics of grout flow in the rough fracture. The results show that grouting pressure exhibited a trend of rapid increase followed by a slow increase with time during the grouting in the tensile and shear fractures. Grouting pressure increases with time in a smooth relationship for tensile fracture and a fluctuating upward relationship for shear fracture. The slurry pressure distribution along the penetration length exhibited a nonlinear attenuation trend. The attenuation degree of the slurry pressure was positively related to the fracture roughness and the roughness difference in the upper–lower fracture surface and negative with the fracture aperture. The potential filtration effect during the grouting process is an important factor affecting the grouting behavior in the rough fracture.

Effective synthesis of fluorescent carbon dots and their application in controllable detection of deferasirox

As an iron chelation therapy, deferasirox (DEF) is commonly used as the primary treatment drug to prevent intracellular iron overload in patients with thalassemia who require long-term and large blood transfusions. However, due to the toxic side effects of long-term use, building a convenient and sensitive DEF detection method remains an important task. This study developed a simple and effective fluorescence detection strategy for DEF based on the coordination effect of DEF and Cu2+ (DEF-Cu). The high quantum yield N-doped blue emission carbon dots (CDs) synthesized by a simple one-step hydrothermal method were applied as the fluorescent probe. The DEF-Cu exhibited a new absorption peak centered at 334 nm, overlapping with the absorption wavelength of CDs, resulting in an internal filtration effect (IFE) for quenching the fluorescence of CDs. The quenching degrees of CDs caused by DEF-Cu showed a good linear relationship in the range of 0.5–20 μg/mL, with a detection limit (LOD) as low as 0.12 μg/mL. The accurate detections of DEF in dispersible tablets and plasma were also achieved. This strategy not only enriched the understanding of the properties of target drugs but also provided valuable insights for designing CDs with specific luminescent properties and applying them to distinctive methods for drug analysis.

Biocompatible bright orange emissive carbon dots: Multifunctional nanoprobes for highly specific sensing toxic Cr(VI) ions and mitochondrial targeting cancer cell imaging

Although several luminescent-based nanostructured materials are used as cellular imaging probes, creating a biocompatible subcellular imaging probe can be challenging. Instantaneously, it is crucial and urgently needed for certain fluorescent nanoprobes to identify possibly harmful heavy metal ions. We present a straightforward one-pot preparation of bright orange emissive (quantum yield approximately 16 %) Nitrogen/Sulfur co-doped carbon dots (N/S CDs) from citric acid and methylene blue as raw materials that will serve as a specific Cr(VI) ions sensor and an effective mitochondrial labeling in cancer cells. They had several benefits including low ecological impact, facile synthesis, good water solubility, photostability, and high stability. We found that N/S CDs photoluminescence (PL) could be reduced when Cr(VI) ions were present near them, and the PL reduction occurred highly sensitively to the presence of Cr(VI) compared to other metal ions including Cr(III) ions. This specific reduction of PL was due to the non-fluorescent complex formation through the inner filter effect (IFE). The established fluorescence-based sensing technique could serve for Cr(VI) ion quantification with exceptional sensing efficiency in the wide linear range of 7 to 70 μM (R2 = 0.9873), with the limit of detection of 53.5 nM. It was also revealed that the current fluorescent probe could be encouragingly utilized to quantify the concentration of Cr(VI) ions in various water specimens such as tap water. In addition, they were shown to function as a mitochondria-targeting nanoprobe in human cancer cells (ME 180 cells and Hela cells) for cell imaging. Concludingly, it was envisioned that these fluorescent nanoprobes could find a use in real-time monitoring of Cr(VI) ions in water-based ecosystems with ultrahigh sensitivity and cell image tracking via mitochondria labeling as biocompatible nanoprobes.

Design and synthesis of high quantum yield doped carbon nano probe derived from household sources for sensing of the anti-GERD drug pantoprazole

This contribution aims to design and validate a new green, cheap, and fast approach for determining the anti-GERD drug pantoprazole in different matrices. New S and N-doped carbon nanomaterials (S,N-CNMs) have been prepared via microwave irradiation of a mixture of widely available household sources. Remarkably, the utilization of a blend of carbamide and thiocarbamide with table sugar yields S,N-CNMs exhibiting the utmost quantum yield (54 %), hydrophilicity, as well as stable, homogeneous, and diminutive particle size distribution. Fourier transform infrared spectroscopy, transmission electron microscopy, spectrophotometry, and fluorescence spectroscopy were applied to characterize the S,N-CNMs. The S,N-CNMs have been used as a turn-off fluorescence probe to determine pantoprazole via a synergism of the inner filter effect and static quenching mechanisms. The fluorescence quenching is linearly correlated to pantoprazole concentration over the range of 1.0–25.0 µg/mL with a detection limit of 0.16 µg/mL. The developed probe exhibited good selectivity for pantoprazole in the presence of variability of substances. Therefore, it was applied for quality control of pantoprazole in pharmaceutical tablets and vials with an average recovery % of 100.10 ± 0.77 % and 100.33 ± 0.92 %, respectively. Moreover, it was successfully implemented to examine the content uniformity of pantoprazole in tablets. Furthermore, the prepared S,N-CNMs have been successfully used for the analysis of pantoprazole in human plasma after a simple protein precipitation step with a recovery % of 97.88 ± 5.72 %. The greenness and blueness of the developed method have been positively assessed by recent tools showing the eco-friendliness and applicability of the developed method.

A Versatile Visual Molecular Imprinting-Driven Switchable Nanozyme Activity-Based Trimodal Assay and Logic Gate Circuits of Ethyl Carbamate.

Concerns regarding the hazard of the carcinogenic ethyl carbamate (EC) have driven attempts to exploit efficient, timely, straightforward, and economic assays for warning early food safety. Here, we proposed a novel molecularly imprinted polymer Co@MOF-MIP, with a high peroxidase (POD)-like activity and a bright blue fluorescence emission, to develop a versatile visual assay for colorimetric, fluorescent, and photothermal trimodal detection and logic gate outputting of EC. Briefly, the POD-like activity of Co@MOF-MIP made it to decompose H2O2 into ·OH for oxidizing colorless 3,3',5,5'-tetramethylbenzidine (TMB) into a blue oxTMB, resulting in a 660 nm irradiated photothermal effect and bursting the blue fluorescence of Co@MOF-MIP via inner filter effect, observing a decreased fluorescence signal together with an increased colorimetric and 660 nm irradiated photothermal signals. However, EC could specifically fill the imprinted cavities of Co@MOF-MIP to block the catalytic substrates TMB and H2O2 out of Co@MOF-MIP for further reacting with the inside catalytic center of Co2+, resulting in the transformation suppressing of TMB into oxTMB, yielding an EC concentration-dependent trimodal responses in fluorescence signal enhancement, colorimetric, and 660 nm irradiated photothermal signal decreases. Assisted by the portable devices such as smartphones and hand-held thermal imagers, a visual onsite portable trimodal analytical platform was proposed for EC fast and accurate detection with the low detection limits of 1.64, 1.24, and 1.78 μg/L in colorimetric, fluorescent, and photothermal modes, respectively. Interestingly, these reactive events could be programmed by the classical Boolean logic gate analysis to offer a novel promising avenue for the big data Internet of Things monitoring and warning early residual EC in a more intelligent, dynamical, fast, and accurate manner, safeguarding food safety.

A Review of Methods of Generating Incremental Capacity–Differential Voltage Curves for Battery Health Determination

Incremental capacity–differential voltage is a powerful tool for transforming raw voltage data from battery cycling data into curves with distinguishable peaks and valleys. These peaks and valleys have been claimed as useful health features in the literature for providing non-invasive, comprehensive insights into a battery’s health and age. Although extensive studies exist on this topic, no standardized approach for generating these curves has been established. This paper analyzes various calculation methodologies and different post-processing filters employed in the literature. These methods are validated using three datasets: two publicly available datasets from Oxford University and a publication from Nature, along with a dataset collected from Loughborough University. The findings highlight the effectiveness of specific calculation methodologies and filters through the differences in the curves produced. Based on the results and analysis, a recommended operational procedure for generating incremental capacity curves is proposed. This standardized procedure aims to enhance the reliability and consistency of producing incremental capacity curves for state-of-health assessments for batteries.

Confinement of CuNCs with aZIF-8 via one-pot encapsulation: Construction of an enzyme-free sensor toward fluorescence and smartphone detection of chlorpyrifos based on the inner filter effect

The excessive use of chlorpyrifos (CPF) has caused serious harm to food and soil safety, so, it is important for the detection of CPF. Herein, a fluorescence sensor (aZIF-8@CuNCs) consisting of copper nanoclusters (CuNCs) wrapped by amorphous zeolite imidazole framework-8 (aZIF-8) was prepared by a facile one-pot strategy to achieve selective detection of CPF. The sensing mechanism is that the fluorescence of aZIF-8@CuNCs can be quenched by 3,5,6-trichloro-2-pyridinol, the hydrolysate of CPF in alkaline condition through the inner filter effect. Therefore, a specific enzyme-free CPF sensing method was constructed by using aZIF-8@CuNCs. The detection range is 0–50 μg/mL and the detection limit reaches 0.43 μg/mL, and the recovery range of CPF in food and soil is 90.6 %-112.9 % with the relative standard deviations less than 6 %. In addition, aZIF-8@CuNCs were successfully combined with a smartphone to realize rapid visualization and quantitative analysis of CPF. This method not only reduces the difficulty of MOF@CuNCs synthesis, but also opens up a new avenue to apply it to pesticide detection in food and soil.

Fluorescent and colorimetric dual-mode detection of Cu2+ based on carbon dots.

A fluorescent and colorimetric dual-mode strategy based on carbon dots (CDs) was rationally designed for sensitive determination of Cu2+. Green fluorescent CDs with high absolute quantum yield of 72.9% were synthesized by facile one-step hydrothermal treatment of triethylenetetramine and Rose Bengal. Cu2+ could trigger the oxidative and chromogenic reaction of p-phenylenediamine (PPD) to generate chromogenic PPDox, accompanied by the fluorescence quenching of the CDs. The quenching mechanism was identified as the inner filter effect between PPDox and CDs. Therefore, a colorimetric/fluorescent dual-mode detection method for Cu2+ recognition was constructed. The limits of detection for Cu2+ were 4.14μM and 1.28μM for colorimetric and fluorescent mode, respectively. In addition, this method had achieved satisfactory results in the detection of Cu2+ in real serum samples.

A ratiometric fluorescence sensor with different responsive modes based on carbon dots-embedded Tb-MOFs for the determination of norfloxacin and levofloxacin

Norfloxacin (NOR) and levofloxacin (LEV) are the two most frequently used fluoroquinolones (FQs) in clinic. Their residues seriously endanger the ecosystem and human health. Due to their similarity in structure and properties, it is urgent to develop an efficient and sensitive strategy for detection and differentiation. Herein, we synthesized a novel ratiometric fluorescent sensor for the first time by combining N, S co-doped carbon dots (CDs) and the precursors of Tb-MOFs through a facile one-pot method. The introduction of CDs effectively facilitated the energy transfer between Tb3+ and FQs, overcoming the limitation that single Tb-MOFs could not identify similar antibiotics. Specifically, the presence of NOR resulted in reverse signal response through the inner filter effect and antenna effect. The synergistic effect of these two mechanisms contributed to achieving signal amplification accompanied by a distinguishable color transition. The limit of detection (LOD) was 0.036 μM. Different from NOR, the addition of LEV reduced the electron density of the system, weakened the coordination ability of Tb3+ with LEV, and induced a single signal response with Tb3+ fluorescence intensity as a reference signal (LOD = 0.383 μM). Furthermore, the method proved to be rapid and visual, allowing for the straightforward analysis of FQs residues in water, food matrices, and biological samples with satisfactory precision. By integrating N, S-CDs@Tb-MOFs with flexible substrates, the paper-based sensor facilitated the visual quantitative determination of FQs by reading RGB values. The developed sensor presents a promising strategy for the identification and real-time monitoring of antibiotics.

Rainwater-borne H2O2 accelerates roxarsone degradation and reduces bioavailability of arsenic in paddy rice soils

Contamination of rice by arsenic represents a significant human health risk. Roxarsone -bearing poultry manure is a major pollution source of arsenic to paddy soils. A mesocosm experiment plus a laboratory experiment was conducted to reveal the role of rainwater-borne H2O2 in the degradation of roxarsone in paddy rice soils. While roxarsone could be degraded via chemical oxidation by Fenton reaction-derived hydroxyl radical, microbially mediated decomposition was the major mechanism. The input of H2O2 into the paddy soils created a higher redox potential, which favored certain roxarsone-degrading and As(III)-oxidizing bacterial strains and disfavored certain As(V)-reducing bacterial strains. This was likely to be responsible for the enhanced roxarsone degradation and transformation of As(III) to As(V). Fenton-like reaction also tended to enhance the formation of Fe plaque on the root surface, which acted as a filter to retain As. The dominance of As(V) in porewater, combined with the filtering effect of Fe plaque significantly reduced the uptake of inorganic As by the rice plants and consequently its accumulation in the rice grains. The findings have implications for developing management strategies to minimize the negative impacts from the application of roxarsone-containing manure for fertilization of paddy rice soils.

Tracing Magnetic Fields with the Gradient Technique: Spatial Filtering Effect and Use of Interferometers

Probing magnetic fields in astrophysical environments is both important and challenging. The Gradient Technique (GT) is a new tool for tracing magnetic fields, rooted in the properties of magnetohydrodynamic (MHD) turbulence and turbulent magnetic reconnection. In this work, we examine the performance of GT when applied to synthetic synchrotron emission and spectroscopic data obtained from sub-Alfvénic and trans-Alfvénic MHD simulations. We demonstrate the improved accuracy of GT in tracing magnetic fields in the absence of low spatial frequencies. Additionally, we apply a low-spatial-frequency filter to a diffuse neutral hydrogen region selected from the GALFA-H i survey. Our results show an increased alignment between the magnetic fields inferred from GT and the Planck 353 GHz polarization measurements.