Substrate Potential Research Articles

Nanoscale Organic Contaminant Detection at the Surface Using Nonlinear Bond Model

Environmental pollution from organic dyes such as malachite green and rhodamine B poses significant threats to ecosystems and human health due to their toxic properties. The rapid detection of these contaminants with high sensitivity and selectivity is crucial and can be effectively achieved using nonlinear optical methods. In this study, we combine the Simplified Bond Hyperpolarizability Model (SBHM) and molecular docking (MD) simulations to investigate the Second-Harmonic Generation (SHG) intensity of organic dyes on a silicon (Si(001)) substrate for nanoscale pollutant detection. Our simulations show good agreement with rotational anisotropy (RA) SHG intensity experimental data across all polarization angles, with a total error estimate of 3%. We find for the first time that the SBHM not only identifies the different organic pollutant dyes on the surface, as in conventional SHG detection, but can also determine their relative orientation and different concentrations on the surface. Meanwhile, MD simulations reveal that rhodamine B shows a strong adsorption affinity of −10.4kcal/mol to a single-layer graphene oxide (GO) substrate, primarily through π-π stacking interactions (36 instances) and by adopting a perpendicular molecular orientation. These characteristics significantly enhance SHG sensitivity. A nonlinear susceptibility analysis reveals good agreement between the SBHM and group theory. The susceptibility tensors confirm that the dominant contributions to the SHG signal arise from both the molecular structure and the surface interactions. This underscores the potential of GO-coated silicon substrates for detecting trace levels of organic pollutants with interaction distances ranging from 3.75Å to 5.81Å. This approach offers valuable applications in environmental monitoring, combining the sensitivity of SHG with the adsorption properties of GO for nanoscale detection.

Design and Engineering of Silver Nanomushroom Arrays as a Universal Solid-State SERS Platform for the Label-Free, Sensitive, and Quantitative Detection of Trace Proteins.

Surface-enhanced Raman scattering (SERS) is an ultrasensitive optical technique that is critical for protein detection and essential for identifying protein structure and concentrations in various biomedical and diagnostic applications. However, achieving highly sensitive and reproducible SERS signals for label-free proteins remains challenging due to their weak Raman signals and structural complexity. In this study, silver nanomushroom arrays (Ag NMAs) as SERS substrates were readily prepared and surface-engineered using a facile template-assisted micro- and nanofabrication approach. The surface of the substrate exhibits nanoscale roughness, long-range order, and hydrophilicity, enabling rapid and uniform dispersion of protein molecules. These molecules are anchored through Ag-S bonds, resulting in ultrasensitive Raman signals driven by strong electromagnetic enhancement effects. The highly ordered array structure improves signal repeatability, achieving a relative standard deviation of as low as 4.32%. Additionally, utilizing the silicon characteristic peak of the SERS substrate as an internal standard significantly reduces measurement errors, allowing for reliable and precise quantitative detection of protein molecules, with a linear correlation coefficient (R2) exceeding 0.96. Ultrasensitive SERS detection and effective protein discrimination via principal component analysis further validate the Ag NMA substrate's potential for universal trace protein detection. This study presents an advanced SERS platform for the sensitive and rapid detection of trace proteins, showcasing significant potential in pharmaceutical research, metabolic studies, diagnostic medicine, and protein engineering.

Annual Garden Rocket and Radish as Microgreens: Seed Germination Response to Thermal and Salt Stress

Temperature and salinity level of the imbibition medium play a crucial role in regulating seed germination and seedling emergence, which is also true in microgreen production, where temperature and water potential may influence seed germination alone and/or in combination. In this study, the effects of different temperatures and water potentials in NaCl, alone or in combination, upon germination and early radicle growth, were assessed in two species for microgreen production (Eruca sativa-rocket, and Raphanus sativus-radish). Seeds were germinated at eight constant temperatures (from 5 to 35 °C) and five water potentials (ψ) in NaCl (from 0 to −1.2 MPa). Final germination percentage (FGP) was maximized at 15–20 °C in rocket, and at 20–25 °C in radish. As the temperature increased or decreased, germination was reduced and became less uniform, to a greater extent, at suboptimal temperatures in both species. Across water potentials, FGP values exceeding 50% at the highest temperature in radish indicated a greater tolerance than rocket to supraoptimal temperatures during germination. Across temperatures, FGP and germination speed in both species were progressively depressed as the water potential decreased. The adverse effects of NaCl progressively increased as the temperature moved away from its optimal value. Overall, rocket seeds were able to germinate well (>80%) at 20 °C at salinity levels down to −0.9 MPa, while radish seeds were able to germinate well (≥90%) at 25 °C at salinity levels down to −0.9 MPa. Salt stress tolerance was higher in rocket and radish at low and high temperatures, respectively. Both thermal time and hydrotime requirements were higher in radish because its seeds took longer to germinate. Thermal time and hydrotime may help to predict the germination capacity and time, once the temperature or water potential of the imbibition substrate is known. The findings of this study have important implications for the large-scale industrial production of microgreens.

Structural Insights into Broad-Range Polyphosphate Kinase 2-II Enzymes Applicable for Pyrimidine Nucleoside Diphosphate Synthesis.

Polyphosphate kinases (PPK) play crucial roles in various biological processes, including energy storage and stress responses, through their interaction with inorganic polyphosphate (polyP) and the intracellular nucleotide pool. Members of the PPK family 2 (PPK2s) catalyse polyP-consuming phosphorylation of nucleotides. In this study, we characterised two PPK2 enzymes from Bacillus cereus (BcPPK2) and Lysinibacillus fusiformis (LfPPK2) to investigate their substrate specificity and potential for selective nucleotide synthesis. Both enzymes exhibited a broad substrate scope, selectively converting over 85 % of pyrimidine nucleoside monophosphates (NMPs) to nucleoside diphosphates (NDPs), while nucleoside triphosphate (NTP) formation was observed only with purine NMPs. Preparative enzymatic synthesis of cytidine diphosphate (CDP) was applied to achieve an yield of 49 %. Finally, structural analysis of five crystal structures of BcPPK2 and LfPPK2 provided insights into their active sites and substrate interactions. This study highlights PPK2-II enzymes as promising biocatalysts for the efficient and selective synthesis of pyrimidine NDPs.

Identification of MORF4L1 as an endogenous substrate of CRBN and its potential role as a therapeutic target in cancer

The ubiquitin-proteasome system (UPS) is essential for cellular homeostasis, regulating the degradation of proteins involved in key processes such as cell cycle, apoptosis, and DNA repair. Dysregulation of the UPS is implicated in hepatocellular carcinoma (HCC), contributing to tumor progression and therapeutic resistance. The cereblon (CRBN) E3 ubiquitin ligase complex is a crucial component of the UPS, particularly in modulating protein degradation in response to small-molecule modulators like thalidomide. However, the endogenous substrates of CRBN in solid tumors like HCC remain poorly characterized. Here, we identify MORF4L1, a member of the MRG family involved in chromatin remodeling and DNA damage response, as a substrate of CRBN. Using proteomic analysis, co-immunoprecipitation, and structural modeling, we demonstrate that CRBN promotes MORF4L1 degradation under physiological conditions, which is further enhanced by the modulator CC-885. Importantly, MORF4L1 is upregulated in multiple cancers, including HCC, suggesting a broader role in tumorigenesis. Our findings reveal MORF4L1 as a physiological CRBN substrate and highlight the therapeutic potential of targeting CRBN substrates in cancer.

Elucidating the binding specificity of interactive compounds targeting ATP-binding cassette subfamily G member 2 (ABCG2).

The ATP-binding cassette transporter superfamily plays a pivotal role in cellular detoxification and drug efflux. ATP-binding cassette subfamily G member 2 (ABCG2) referred to as the Breast cancer resistance protein has emerged as a key member involved in multidrug resistance displayed by cancer cells. Understanding the molecular basis of substrate and inhibitor recognition, and binding within the transmembrane domain of ABCG2 is crucial for the development of effective therapeutic strategies. Herein, utilizing state-of-the-art molecular docking algorithms and molecular dynamic (MD) simulations, molecular binding of substrates and inhibitors with ABCG2 are defined, distinctly. We performed extensive virtual screening of Drugbank to identify the potential candidates, and MD simulations of docked complexes were carried out in POPC lipid bilayer. Further, the binding affinities of compounds were estimated by free binding energy employing MM-GBSA. To gain deeper insight into the binding affinities and molecular characteristics contributing to inhibitory potential of certain substrates, we included some well-known inhibitors, like Imatinib, Tariquidar, and Ko 143, in our analysis. Docking results show three compounds, Docetaxel > Tariquidar > Tezacaftor having the highest binding affinities (≤12.00kcal/mol) for ABCG2. Remarkably, MM-GBSA results suggest the most stable binding of Tariquidar with ABCG2 as compared to the other inhibitors. Furthermore, our results suggested that Docetaxel, Ozanimod, Pitavastatin, and Tezacaftor have the strongest affinity for the drug-binding site(s) of ABCG2. These results provide valuable insights into the key residues that may govern substrate/inhibitor recognition, shedding light on the molecular determinants influencing substrate specificity, transport kinetics, and ABCG2-mediated drug efflux.

Computational self-assembly of a six-fold chiral quasicrystal.

Quasicrystals are unique materials characterized by long-range order without periodicity. They are observed in systems such as metallic alloys, soft matter, and particle simulations. Unlike periodic crystals, which are invariant under real-space symmetry operations, quasicrystals possess symmetry that requires description by a space group in reciprocal space. In this study, we report the self-assembly of a six-fold chiral quasicrystal using molecular dynamics simulations of a two-dimensional particle system. The particles interact via the Lennard-Jones-Gauss pair potential and are subjected to a periodic substrate potential. We confirm the presence of chiral symmetry through diffraction patterns and order parameters, revealing unique local motifs in both real and reciprocal space. The quasicrystal's properties, including the tiling structure and symmetry and the extent of diffuse scattering, are strongly influenced by substrate potential depth and temperature. Our results provide insights into the mechanisms of chiral quasicrystal formation and the role and potential of external fields in tailoring quasicrystal structures.

Substrate Integrated Waveguide on Glass with Vacuum-Filled Tin Through Glass Vias for Millimeter-Wave Applications.

This paper presents a novel approach to fabricate substrate integrated waveguides (SIWs) on glass substrates with tin (Sn) through glass vias (TGVs) tailored for millimeter-wave applications. The fabrication process employs a custom-designed vacuum suctioning system to rapidly fill precise TGV holes in the glass substrate, which are formed by wafer-level glass reflow micromachining techniques with molten tin in a minute. This method offers a very fast and cost-effective alternative for complete via filling without voids compared to the conventional metallization techniques such as electroplating or sputtering. An SIW with a 3-dB cutoff frequency of 17.2 GHz was fabricated using the proposed process. The fabricated SIW shows an average insertion loss of 1.65 ± 0.54 dB across the 20-35 GHz range. These results highlight the potential of glass substrates with tin TGVs for fabricating millimeter-wave devices.

Photochemical Deracemization of Lactams with Deuteration Enabled by Dual Hydrogen Atom Transfer.

Photochemical deracemization has emerged as one of the most straightforward approaches to access highly enantioenriched compounds in recent years. While excited-state events such as energy transfer, single electron transfer, and ligand-to-metal charge transfer have been leveraged to promote stereoablation, approaches relying on hydrogen atom transfer, which circumvent the limitations imposed by the triplet energy and redox potential of racemic substrates, remain underexplored. Conceptually, the most attractive method for tertiary stereocenter deracemization might be hydrogen atom abstraction followed by hydrogen atom donation. However, implementing such a strategy poses significant challenges, primarily because the enantioenriched products are also reactive if the chiral catalyst is unable to differentiate between the two enantiomers. Herein we report a distinct dual hydrogen atom transfer strategy for photochemical deracemization of δ- and γ-lactams, achieving high enantioenrichment and deuterium incorporation despite the inherent reactivity of the products. Mechanistic studies reveal that benzophenone enables nonselective hydrogen atom abstraction while a tetrapeptide-derived thiol dictates the enantioselectivity of the hydrogen atom donation step. More importantly, a pyridine-based alcohol was found to play crucial roles in facilitating the hydrogen atom abstraction as well as enhancing the enantioselectivity of the hydrogen atom donation step.

Bio-Inspired Eco-Composite Materials Seaweed Waste Integration for Sustainable Structural Applications

The increasing levels of atmospheric carbon dioxide (CO2) and plastic waste in marine environments demand immediate action to mitigate their effects. A promising solution lies in enhancing algal cultivation in marine environments, which not only absorbs CO2 and produces oxygen (O2) but also contributes to carbon sequestration. This study aims to develop biodegradable substrates for algae cultivation, facilitating their gradual degradation in marine environments and eventual deposition on the ocean floor, thereby addressing both plastic pollution and CO2 emissions. We selected various degradable polymers and incorporated differing proportions of algae residue powder (10%, 20%, and 30% by weight) into these substrates. The compositions were processed through extrusion and molded into test samples for hot compression molding. Characterization included assessments of mass loss, morphology, chemical composition, and mechanical strength under both dry conditions and after immersion in seawater for up to two months. The results indicate that the incorporation of algae residue significantly accelerates the degradation of the samples, particularly under extended exposure to seawater. Mass loss measurements indicated that samples with a 30 wt% algae addition experienced mass losses of up to 12% after two months of immersion. Mechanical strength tests demonstrated a reduction of up to 57% in strength due to the incorporation of algae, with seawater immersion further exacerbating this loss. These findings highlight the potential of biopolymer substrates infused with algae residue for effective carbon sequestration through enhanced algae cultivation.

Enantioselective Three‐Component α‐Allylic Alkylation of α‐Amino Esters by Synergistic Photoinduced Pd/Carbonyl Catalysis

AbstractPhotoinduced excited‐state Pd catalysis has emerged as an intriguing strategy for unlocking new reactivity potential of simple substrates. However, the related transformations are still limited and the enantiocontrol remains challenging. Organocatalysis displays unique capability in substrate activation and stereocontrol. Combination of organocatalysis and photoinduced excited‐state Pd catalysis may provide opportunities to develop new enantioselective reactions from simple substrates. By applying cooperative triple catalysis including excited‐state Pd catalysis, ground‐state Pd catalysis, and carbonyl catalysis, we have successfully realized enantioselective α‐allylic alkylation of α‐amino esters with simple styrene and alkyl halide starting materials. The reaction allows rapid modular assembly of the three reaction partners into a variety of chiral quaternary α‐amino esters in good yields with 90–99 % ee, without protecting group manipulations at the active NH2 group. The cooperation of the chiral pyridoxal catalyst and the chiral phosphine ligand accounts for the excellent chirality induction.

Enantioselective Three-Component α-Allylic Alkylation of α-Amino Esters by Synergistic Photoinduced Pd/Carbonyl Catalysis.

Photoinduced excited-state Pd catalysis has emerged as an intriguing strategy for unlocking new reactivity potential of simple substrates. However, the related transformations are still limited and the enantiocontrol remains challenging. Organocatalysis displays unique capability in substrate activation and stereocontrol. Combination of organocatalysis and photoinduced excited-state Pd catalysis may provide opportunities to develop new enantioselective reactions from simple substrates. By applying cooperative triple catalysis including excited-state Pd catalysis, ground-state Pd catalysis, and carbonyl catalysis, we have successfully realized enantioselective α-allylic alkylation of α-amino esters with simple styrene and alkyl halide starting materials. The reaction allows rapid modular assembly of the three reaction partners into a variety of chiral quaternary α-amino esters in good yields with 90-99 % ee, without protecting group manipulations at the active NH2 group. The cooperation of the chiral pyridoxal catalyst and the chiral phosphine ligand accounts for the excellent chirality induction.

Gel composite membrane with tannic acid/ferric ion separation layer for organic solvent nanofiltration

To address the permeability-selectivity trade-off of organic solvent nanofiltration (OSN) membranes, a gel composite membrane was fabricated by the complexation of tannic acid (TA) and ferric ions (Fe3+) on the surface of self-supported calcium alginate (CaAlg) gel membrane. The three-dimensional network of the CaAlg substrate serves as a channel for rapid solvent transport, while the dense TA/Fe3+ metal-phenol network achieves solute rejection. The chemical structure, morphology, pore size, zeta potential and mechanical properties of the CaAlg substrate and the gel composite membrane were characterized. Dye/solvent separation and solvent resistance were investigated. The results indicate that the TA/Fe3+ separation layer reduces the pore size, increases the negative charge and improves the mechanical properties of the gel membrane. By optimizing the TA/Fe3+ complexation conditions, the gel composite membrane has an ethanol permeance of 19.5 L m−2 h−1 bar−1 and a congo red (CR) rejection of 99.0 %, and the separation performance is almost unchanged during 60 d of immersion in N, N-dimethlformamide (DMF). In addition, the composite membrane could separate CR from DMF and acetone, as well as cationic and anionic dyes in ethanol. This work provides a simple and environmentally friendly method to prepare an OSN membrane with high solvent permeance and harsh solvent stability, which is promising for solvent purification and recovery.

Microbial mats writing the fossil record of true substrates in clastic rock successions

True substrates are bedding surfaces that represent the original environmental surfaces that existed at the time of burial. In the clastic depositional regime, there are abiotic and biotic causes that may contribute to the formation of such true substrates. This paper focuses on how sediment-stabilizing microbial mats may increase the preservation potential of true substrates. Baffling and trapping enrich fine-grained particles and heavy minerals in mat textures inducing a layer of heterogeneity in the otherwise homogenous deposits. Together with in situ mineral precipitation during the life time of the microbial mat and post-depositional diagenesis, baffling and trapping contributes to processes leading to bedding plane preservation. Microbial mats interact with the hydrological system of a coastal environment causing typical microbially induced sedimentary structures (MISS). The morphologies of MISS can indicate climate seasonality and zone of the respective true substrate. The interaction of animals and plants with microbial mats allow reconstructing events that took place during the exposure of the original environmental surface. Finally, true substrates displaying MISS are well-defined indicators for life exploration of Earth's oldest sedimentary rock successions and equivalent lithologies on other planets.

Valuable Ca/P Sources Obtained from Tuna Species’ By-Products Derived from Industrial Processing: Physicochemical and Features of Skeleton Fractions

The global tuna canning industry generates substantial volumes of by-products, comprising 50% to 70% of the total processed material. Traditionally, these by-products have been utilized in low-value products such as fish oils and fishmeal. However, there is significant potential to extract high-value compounds from these by-products, such as calcium phosphates (CaP), which can have pharmaceutical, agricultural and biotechnological applications. This work explores the potential of tuna canning by-products, particularly mineral-rich fractions (central skeleton, head and fish bones) as sources of calcium phosphates (CaP), offering a sustainable alternative to conventional synthetic derivatives within a circular bioeconomy framework. By-products from two of the most exploited species (yellowfin and skipjack) were subjected to enzymatic hydrolysis and chemical extraction, followed by controlled calcination to obtain CaP. The content of organic matter, nitrogen, total proteins, lipids and amino acids in the cleaned bones, as well as the main chemical bonds, structure and elemental composition (FT-Raman, XRD, XRF) were evaluated. Results indicated that the highest recovery yield of wet bones was achieved using the chemical method, particularly from the dorsal and caudal fins of yellowfin tuna. The proximal composition, with ash content ranging from 52% to 66% and protein content varying between 30% and 53%, highlights the potential of tuna skeleton substrates for plant growth formulations. Furthermore, variations in crystalline structures of the substrates revealed significant differences depending on the by-product source and species. XRD and Raman results confirmed a monophase calcium phosphate composition in most samples from both species, primarily based on hydroxyapatite (central skeleton, caudal and dorsal fin) or whitlockite/β-tricalcium phosphate (viscera), whereas the heads exhibited a biphasic composition. Comparing the species, yellowfin tuna (YF) exhibited a hydroxyapatite structure in the branchial arch and scales, while skipjack (SKJ) had a biphasic composition in these same regions.

Prediction of polybrominated diphenyl ethers (PBDEs) as potential substrates of various human CYP enzymes and laboratory test of BDE-99 for its metabolism-activated mutagenicity

Polybrominated diphenyl ethers (PBDEs) are persistent organic pollutants, of which BDE-47 could be activated by human cytochrome P450s (CYPs) for chromosome-damaging effects. However, the metabolic activation and mutagenicity of other PBDEs remain unknown. In this study, 14 representative PBDEs were analyzed by molecular docking as potential substrates for several human CYPs. The results showed negative free energies for each pair of binding, however, different CYPs demonstrated largely varied frequencies of binding conformations favoring a substrate potential: CYP2E1, 3A4, and 2B6 being suitable for all/most compounds. Using BDE-99 (5 ∼ 40 μM) as a model compound (exposing for 2 cell cycles), it did not induce micronucleus in a human hepatoma HepG2 cell line, however, positive result was observed in C3A cells (derived from HepG2 but with enhanced expression of CYPs). Pretreatment of HepG2 cells with each of bisphenol A (1 μM, inducer of CYPs) and CITCO (10 μM, inducer of CYP2B6) led to micronucleus formation by BDE-99, while the effect of BDE-99 in C3A cells was abolished by 1-aminobenzotriazole (60 μM, inhibitor of CYPs). In a V79-derived cell line genetically engineered for expressing human CYP2B6 BDE-99 induced micronucleus, while it was negative in V79-Mz and its derivatives expressing several other human CYPs. The micronuclei formed in HepG2 cells pretreated with BPA and CITCO were free of centromere protein B immunofluorescence staining. Finally, BDE-99 weakly induced PIG-A gene mutations in C3A, while negative in HepG2 cells. In conclusion, our study suggest that BDE-99 may be activated by human CYP2B6 for chromosome-breaking effects.

Stannous Chloride-Modified Glass Substrates for Biomolecule Immobilization: Development of Label-Free Interferometric Sensor Chips for Highly Sensitive Detection of Aflatoxin B1 in Corn.

This study presents the development of stannous chloride (SnCl2)-modified glass substrates for biomolecule immobilization and their application in fabricating sensor chips for label-free interferometric biosensors. The glass modification process was optimized, identifying a 5% SnCl2 concentration, a 45 min reaction time, and a 150 °C drying temperature as conditions for efficient protein immobilization. Based on the SnCl2-modified glass substrates and label-free spectral-phase interferometry, a biosensor was developed for the detection of aflatoxin B1 (AFB1)-a highly toxic and carcinogenic contaminant in agricultural products. The biosensor realizes a competitive immunoassay of a remarkable detection limit as low as 26 pg/mL of AFB1, and a five-order dynamic range. The biosensor performance was validated using real corn flour samples contaminated with Aspergillus flavus. The proposed approach not only provides a powerful tool for AFB1 detection for food safety monitoring but also demonstrates the potential of SnCl2-modified substrates as a versatile platform for the development of next-generation biosensors.

Investigation of the bacterial diversity in fermented mangrove apple (Sonneratia caseolaris) fruit juice kombucha using DNA metabarcoding

Abstract. Visakhadevi JA, Andriyono S, Satyantini WH, Noh NIM. 2024. Investigation of the bacterial diversity in fermented mangrove apple (Sonneratia caseolaris) fruit juice kombucha using DNA metabarcoding. Biodiversitas 25: 3201-3207. Kombucha, a functional beverage produced from the symbiosis between bacteria and yeast, varies in microbial composition and biological activity depending on the raw materials used for fermentation. This study investigated the potential of mangrove apple (Sonneratia caseolaris (L.) Engl.) fruit juice as a novel substrate for kombucha fermentation because of its high nutritional value and underutilization. We analyzed the bacterial composition of kombucha using a molecular metabarcoding approach with the universal 16S rRNA primers 27F (AGA GTT TGA TCM TGG CTC AG) and 1492R (GGT TAC CTT GTT ACG ACT T). The optimal bacterial density was observed on the 8th day of fermentation, with a value of 1.402. The pH progressively decreased during the fermentation period. This study successfully explored the diversity of bacteria in kombucha grown in apple fruit juice. The dominant bacterial taxon was acetic acid bacteria, with 75,009 reads for Acetobacteraceae. At the genus level, Komagataeibacter was predominant, with 74,660 reads, and at the species level, Komagataeibacter saccharivorans was the most abundant, with 67,502 reads. These results suggest mangrove apple fruit juice as the viable substrate for kombucha fermentation that supports a rich microbial community. This study highlights the potential of alternative substrates, such as mangrove apple fruit juice, to enhance kombucha's microbial diversity and health benefits.

Parameter-induced logical stochastic resonance in substrate potential with deformable sine-Gordon shape

Logical stochastic resonance (LSR) systems are physical nonlinear systems capable of robust Boolean logic operations under the influence of noise. While LSR systems suitable for electronic circuit implementation have been extensively studied, research on condensed matter LSR systems remains limited to constrained bistability with saturation characteristic. Considering the presence of periodic nonlinearities in many physical systems, a deformable sine-Gordon-shaped Remoissenet–Peyrard potential (RPP)-based LSR system is proposed for the first time in this work. Testing under both noise-free and noisy conditions proves the existence of parameter-induced LSR phenomena in the proposed system. Moreover, we find that a relatively wide potential well shape contributes to enhanced noise robustness in the RPP-based LSR system. Additionally, traditional polynomial nonlinearity-based LSR systems are compared with the proposed system. Regardless of whether the noise is Gaussian white noise or composite noise containing spiking pulses, the RPP-based LSR system exhibits superior robustness. The results demonstrate the exceptional advantages of the RPP-based LSR system and encourage further design of condensed matter LSR systems based on deformable periodic nonlinearities.

NiO/AgNPs nanowell enhanced SERS sensor for efficient detection of micro/nanoplastics in beverages

The ubiquity of plastic products has led to an increased exposure to micro and nano plastics across diverse environments, presenting a novel class of pollutants with substantial health implications. Emerging research indicates their capacity to infiltrate human organs, posing risks of tissue damage and carcinogenesis. Given the prevalent consumption of beverages as a primary vector for these plastics' entry into the human system, there is an imperative need for the advancement of precise detection methodologies in liquids. In this study, we introduce a substrate comprising a Nickel Oxide (NiO) nanosheet array decorated with Silver Nanoparticles (AgNPs) for the Surface-Enhanced Raman Spectroscopy (SERS) analysis of micro//nano plastics. This configuration, leveraging a unique nanowell architecture alongside silver plasmonic enhancement, demonstrates unparalleled sensitivity and repeatability in signal, facilitating the accurate quantification of these contaminants. Through the application of a portable Raman apparatus, this study successfully identifies prevalent micro/nano plastics including polystyrene (PS), polyethylene (PE), and polypropylene (PP), achieving detection sensitivities of 5 μg/mL, 25 μg/mL, and 25 μg/mL, respectively. Moreover, the substrate's efficacy extends to the detection of PS within commonly consumed beverages such as water, milk, and liquor with sensitivities of 25 μg/mL, 50 μg/mL, and 50 μg/mL, respectively. These findings highlight the substrate's potential as an expedient and effective sensor for the real-time monitoring of micro/nano plastic pollutants.