Sensitivity Degradation Research Articles

A responsive cocktail nano-strategy breaking the immune excluded state enhances immunotherapy for triple negative breast cancer.

The exclusion of immune cells from the tumor can limit the effectiveness of immunotherapy in triple negative breast cancer (TNBC). The cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) pathway plays a crucial role in priming adaptive anti-tumor immunity through the production of type I interferons (IFNs), facilitating the maturation of dendritic cells (DCs) and the function of T cells. Although the increased expression of programmed death-ligand 1 (PD-L1) upon STING activation is favorable for amplifying the efficacy of immune checkpoint inhibitors (ICIs) and realizing combination therapy, the penetration barrier remains a major obstacle. Herein, we fabricated a smart-responsive nanosystem (B&V@ZB-MCL) by integrating the extracellular matrix (ECM)-degrading drug losartan with a STING agonist (Vadimezan, abbreviated to Vad) and a PD-L1 inhibitor (BMS-1). Losartan was first released in the acidic tumor microenvironment to overcome the physical barrier, enhancing the penetration of immunotherapeutic components. Under the triggering of 1O2 generated by a photosensitizer (Ce6), the reactive oxygen species (ROS)-sensitive degradation of the nanocore ensured the site-directed release of Vad and BMS-1. The released Vad and damaged tumor DNA activated immune responses through the cGAS-STING pathway, while the elevated expression level of PD-L1 promoted the anti-tumor effect of BMS-1. Significant degradation of collagen fibers, restoration of immune effector cells, and lower tumor volume were observed in this integrated triple drug sequential therapy, which provides a promising prospect for TNBC treatment.

Shadow Effect-Triggered Photosensitive Gate of Organic Photoelectrochemical Transistor for Enhanced Biodetection.

The integration of a photosensitive gate into an organic electrochemical transistor has currently emerged as a promising route for biological sensing. However, the modification of the photosensitive gate always involves complex processes, and the degradation of sensitivity of the functional materials under illumination will significantly decrease the stability of the devices. Herein, we designed an organic photoelectrochemical transistor (OPECT) biosensor employing horseradish peroxidase (HRP)@glucose oxidase (GOx)/Pt/n-Si as the photosensitive gate based on the "shadow effect". The glucose-dependent hydrogen peroxide with HRP/GOx was modified on the gate electrode, triggering a biocatalytic precipitation reaction, which induces the illumination contrast, resulting in a biologically gating effect on the corresponding channel current response. Thus, high sensitivity and selectivity in glucose detection of the OPECT devices will be realized. Given the easy fabrication and high stability of the Pt/n-Si electrode, it has great potential to become a superior selectivity as an OPECT gate electrode. This work provides conceptual validation for the study of the interaction between the photosensitive gate based on the "shadow effect" and biomolecular sensing, which can further expand the application of the OPECT biosensors under interior lighting and shadow surroundings.

Long-term properties of coronal off-limb structures

Extracting plasma structures in the solar corona (e.g. jets, loops, prominences) from spacecraft imagery data is essential in order to ascertain their unique properties and for our understanding of their evolution. Hence, our aim is to detect all coronal off-limb structures over a solar cycle and to analyse their statistical properties. In particular, we investigated the intensity and density evolution of these coronal structures, with a specific focus on active longitudes in the corona, that is, longitudinal regions where the solar activity is unequivocally dominant. We developed a methodology based on mathematical morphology (MM) algorithms to extract these coronal structures from extreme ultraviolet (EUV) images taken by the Solar Dynamics Observatory (SDO)/Atmospheric Imaging Assembly (AIA) in the 304 wavelength channel during Solar Cycle (SC) 24. The resulting dataset consists of $877,843$ structures spanning the whole period from June 2010 to December 2021 with a three-hour cadence. We assessed the main characteristics of these coronal off-limb structures, such as their length, width, area, perimeter, latitude, and longitude (evaluated at the centre of the structures), as well as their intensity corrected for the charge-coupled device (CCD) sensitivity degradation of the AIA instrument. Regarding most of these properties, we find similar trends to the behaviour of the on-disk features, including the butterfly diagram and the structures that migrate towards the polar regions (also referred to as `rush-to-the-poles' structures) expanding during the rising phase of SC 24 until the reversal of the magnetic field at the solar poles. We uncover an interesting distribution: lower-intensity coronal structures seem to behave differently with respect to higher-intensity structures. The butterfly diagram is clearly shaped by the high-intensity structures, while the lower-intensity structures are more dispersed and survive during the declining phase of SC 24. We also find evidence of the existence of active longitudes in the corona and of their dependence on differential rotation and latitude.

The Electrical and Mechanical Behaviors of Copper Thin Films Deposited on Polyethylene Terephthalate Under Tensile Stress

This study examines copper thin films under tensile stress and their shape and percentage change in electrical resistance (PCER) as a function of applied strain. Copper films of 100 and 200 nm thickness were sputtered onto polyethylene terephthalate (PET) substrates and were then sequentially stretched to examine how film thickness affects strain-induced morphological changes and electrical resistance. A scanning electron microscope (SEM) was used to track crack patterns, and electrical resistance was monitored throughout tensile testing. Thinner films (100 nm) had quick crack initiation and propagation, leading to an increase in PCER under strain, while thicker films (200 nm) had more gradual morphological and electrical resistance changes. This differential reaction demonstrates the importance of film thickness in mechanical deformation and strain sensitivity, which could affect the design of flexible electronic devices that require mechanical durability and reliable electrical performance. These findings will help to optimize film thickness for stretchable sensors and wearable electronics to balance strain sensitivity and morphological degradation. This study will help designers and users of sensors, stretchable electronics, and other devices that require mechanical durability and electrical performance to understand the relationship between mechanical deformation and electrical properties in thin films. This paper aligns with the ninth goal of the United Nations Sustainable Development Goals, specifically Target 9.5: Enhance Research and Upgrade Industrial Technologies.

A portable bifunctional platform of aluminum/alkalized carbon nitride/silver for sensitive SERS detection and efficient photocatalytic degradation of malachite green

It is necessary to construct a portable bifunctional substrate with high-repeatability and low-cost for detection and degradation of pollutants in practical applications. Herein, the alkalized carbon nitride (ACN) is assembled onto the etched aluminum sheet (EAl) by hydrogen bonding self-assembly which induces the porous structure of EAl/ACN. Subsequently, Ag nanoparticles (AgNPs) are mainly in-situ embedded in the cavities of EAl/ACN, and finally a portable bifunctional substrate of EAl/ACN/Ag is constructed. The surface-enhanced Raman scattering (SERS) response of the EAl/ACN/Ag is highly sensitive and selective for detection of malachite green (MG), and the limit for MG can reach 5.53 × 10-13 mol/L with an enhancement factor (EF) of 2.95 × 105. In addition, the EAl/ACN/Ag substrate shows excellent homogeneity, stability, recyclability and reproducibility. Moreover, the EAl/ACN/Ag substrate displays a high photocatalytic degradation efficiency of 96.4 % for MG within 50 mins even if it is reused for five cycles. Therefore, the developed portable bifunctional substrate shows bright prospects for the detection and removal of organic pollutants in the fields of industrial wastewater analysis.

Fluorescent Ionic Liquid Aggregates: A Self-Assembled Approach for Pesticide Detection and Catalysis.

The unregulated use of pesticides, industrial discharge of heavy metals, waste, and agricultural runoff may contaminate surface water and groundwater, consequently threatening ecosystems and human health. Thus, the sensitive detection and degradation of pesticides are essential for safety. In this context, herein, we have developed benzimidazolium-based fluorescent surfactant assemblies TA-1/SDS and TA-2/SDBS, which exhibit aggregation-induced emission enhancement in an aqueous medium. The aggregates (TA-1/SDS and TA-2/SDBS) displayed a turn-on emission response upon interaction with carbendazim and azamethiphos with limits of detection 7.5 and 7.8 nM, respectively. The FE-SEM and AFM studies revealed that TA-1/SDS and TA-2/SDBS undergo self-assembly with the addition of AZA and CBZ, resulting in the formation of dendritic structures. In addition to the quantification of AZA and CBZ, TA-1/SDS and TA-2/SDBS have also been evaluated to degrade both pesticides and validated using 31P NMR spectroscopy and LC-MS spectrometry.

Design of a novel high-sensitive SOI-Junctionless BioFET overcoming sensitivity degradation problems

For the first time, a new configuration of label-free junctionless semiconductor device is proposed to boost sensitivity in the identification of biomolecule specifies. Instead of creating the nanocavity inside the gate oxide, the nanocavity is created in the channel region which is very useful for the SOI junctionless technology based biodevice having a high current in all operating modes. For better control of the conduction mechanism, a hole trench is created under the channel region just inside the buried oxide. This will help to modulate the energy bands terminating in enhancing the sensing performance. Unlike the conventional biosensors needing a large-scale gate oxide thickness for trapping the biomolecules, the proposed biosensor can work for very low gate oxide thickness. The different biomolecules such as Biotin, Protein A, Bacteriophage T7, and Apomyoglobin have been utilized as targeted biomolecules for evaluating the sensitivity. Comparing the proposed biosensor with the conventional and other biosensors showed an enhanced sensing performance. Practical related issues during the process of sensing in terms of fill factor percentage, steric hindrance of biomolecules, and the charges of biomolecules have been focused in the recommended biodevice. All the results exhibited high superiority of performance of the suggested biodevice as compared to the conventional biosensor.

Probing ultralight scalar, vector and tensor dark matter with pulsar timing arrays

Pulsar timing arrays (PTAs) are sensitive to oscillations in the gravitational potential along the line-of-sight due to ultralight particle pressure. We calculate the probing power of PTAs for ultralight bosons across all frequencies, from those larger than the inverse observation time to those smaller than the inverse distance to the pulsar. We show that since the signal amplitude grows comparably to the degradation in PTA sensitivity at frequencies smaller than inverse observation time, the discovery potential can be extended towards lower masses by over three decades, maintaining high precision. We demonstrate that, in the mass range 10−26−10−23 eV, existing 15-year PTA data can robustly detect or rule out an ultralight component down to O(1−10)% of the total dark matter. Non-detection, together with other bounds in different mass ranges, will imply that ultralight scalar/axion can comprise at most 1−10% of dark matter in the 10−30−10−17 eV range. With 30 years of observation, current PTAs can extend the reach down to 0.1−1%, while next-generation PTAs such as SKA can attain the 0.01−0.1% precision. We generalize and derive predictions for ultralight spin-1 vector (i.e. dark photon) and spin-2 tensor dark components.

Deposition of a polymer thin film on a silver surface for surface plasmon sensing

We report a deposition method of a polymer thin film on the silver surface of a surface plasmon sensor for preventing sensitivity degradation in refractive index measurements due to the poor chemical stability of the silver. The deposition of a poly(methyl methacrylate) thin film with a ∼15 nm thickness was conducted by employing a spin coating technique along with a hydrophilicity enhancement of the silver surface using an atmospheric low-temperature plasma treatment. We experimentally verified the thickness by measuring the propagation constant of the surface plasmon. The measured propagation constants that showed the standard deviation at the order of 10−4 indicated microscopical uniformity. Furthermore, the reproducibility of thickness was experimentally verified.

Best Practices to Directly Assess Heterogeneous Singlet Oxygen Photosensitization by Phosphorescence

AbstractLiterature proves that the direct detection of 1O2(1Δg) at the solid gas interface is systematically performed from its phosphorescence using high intensity excitation sources (i.e., lasers), which lead to quasi‐ubiquitous chemical problems, such as sensitizer degradation, and photophysical counter‐active issues such as ultrafast exciton migration, singlet‐singlet and triplet‐triplet annihilation, and thermally activated delayed fluorescence mediated by 1O2(1Δg). To avoid these inconveniences, low excitation intensity is required but leads to serious analytical challenges. The best practices to reliably detect 1O2(1Δg) phosphorescence at various interfaces using a standard excitation source and near‐IR detector. The two main practices consist in a gas purging test for reliable identification of 1O2(1Δg), and in a particularly fine optimization of the angle made by excitation beam versus substrate plane. These practices are applied to porphyrin sensitizers H2TPP and ZnTPP, either neat or physiosorbed on glass, quartz, paper and hospital bandages, graphene oxide (GO), and embedded inside electrospun polystyrene fibers and spin coated poly(methyl methacrylate) films. Porphyrin‐based metal‐organic framework PCN‐224, freshly activated, is also examined.

Multifunctional Pr-V2O5/rGO hybrid nanomaterial for sensitive heavy metal ion detection and efficient photocatalytic dye degradation

Multifunctional Pr-V2O5/rGO hybrid nanomaterial for sensitive heavy metal ion detection and efficient photocatalytic dye degradation

Plasmon AgNPs/MoS2/ZnO nanorods array ternary heterojunctions enabling high-efficiency solar-light energy utilization for photocatalysis and recyclable SERS detection

BackgroundSurface-enhanced Raman scattering (SERS) has gained widespread use in molecule-level detection benefiting from its high sensitivity, nondestructive data acquisition, and capacity for providing molecular fingerprint information. However, the strong adhesion of target molecules to the substrate (known as the “memory effect”) inherently hinders the reusability of SERS substrates. Research has shown that self-cleaning SERS substrates based on versatile semiconductor materials with SERS enhancement capabilities and solar photocatalytic properties offer an effective platform for the sensitive detection and degradation of harmful molecules. ResultsIn this research, a resuable SERS-active substrate was facilely fabricated by anchoring silver nanoparticles (AgNPs) to the edges of MoS2 nanosheet decorated on ZnO nanorod arrays (NRAs). This innovative design exhibited a remarkable SERS enhancement factor (EF) of 4.6 × 107 and demonstrated significant solar photocatalytic efficiency. Such superior characteristics of ternary plasma heterojunction were ascribable to the synergistic effect of the “Schottky barrier” and “hot spots” between MoS2 and AgNPs, the inherent chemical enhancement proficiency of the MoS2/ZnO NRAs heterojunction, as well as the ultrafast electron transfer within the ternary heterojunction. SignificanceThe developed ternary heterojunction substrate enabled highly sensitive SERS detection of trace amounts of organic molecules. Moreover, this SERS substrate exhibited self-cleaning and recyclability via solar-light-driven photocatalysis. This bifunctional recyclable SERS substrate proved capable of meeting various requirements for routine monitoring of environmental organic pollutants and provided a robust avenue for advancing energy utilization materials that serve as high-performance SERS sensors and catalysts.

Simultaneous photocatalytic degradation and SERS detection of tetracycline with self-sustainable and recyclable ternary PI/TiO2/Ag flexible microfibers

Facile and efficient photocatalysts using sunlight, as well as fast and sensitive surface-enhanced Raman spectroscopy (SERS) substrates, are urgently needed for practical degradation of tetracycline (TC). To meet these requirements, a new paradigm for PI/TiO2/Ag organic‒inorganic ternary flexible microfibers based on semiconducting titanium dioxide (TiO2), the noble metal silver (Ag) and the conjugated polymer polyimide (PI) was developed by engineering a simple method. Under sunlight, the photocatalytic characteristics of the PI/TiO2/Ag flexible microfibers containing varying amounts of Ag quantum dots (QDs) were evaluated with photocatalytic degradation of TC in aqueous solution. The results demonstrated that the amount of Ag affected the photocatalytic activity. Among the tested samples, PI/TiO2/Ag-0.07 (93.1%) exhibited a higher photocatalytic degradation rate than PI/TiO2 (25.7%), PI/TiO2/Ag-0.05 (77.7%), and PI/TiO2/Ag-0.09 (63.3%). This observation and evaluation conducted in the present work strongly indicated a charge transfer mechanism. Moreover, the PI/TiO2/Ag-0.07 flexible microfibers exhibited highly sensitive SERS detection, as demonstrated by the observation of the Raman peaks for TC even at an extremely low concentration of 10–10 moles per liter. The excellent photocatalytic performance and SERS detection capability of the PI/TiO2/Ag flexible microfibers arose from the Schottky barrier formed between Ag and TiO2 and also from the outstanding plasmonic resonance and visible light absorptivity of Ag, along with immobilization by the PI. The successful synthesis of PI/TiO2/Ag flexible microfibers holds significant promise for sensitive detection and efficient photocatalytic degradation of antibiotics.

Fe-Co-Based Metal-Organic Frameworks as Peroxidase Mimics for Sensitive Colorimetric Detection and Efficient Degradation of Aflatoxin B1.

Building multifunctional platforms for integrating the detection and control of hazards has great significance in food safety and environment protection. Herein, bimetallic Fe-Co-based metal-organic frameworks (Fe-Co-MOFs) peroxidase mimics are prepared and applied to develop a bifunctional platform for the synergetic sensitive detection and controllable degradation of aflatoxin B1 (AFB1). On the one hand, Fe-Co-MOFs with excellent peroxidase-like activity are combined with target-induced catalyzed hairpin assembly (CHA) to construct a colorimetric aptasensor for the detection of AFB1. Specifically, the binding of aptamer with AFB1 releases the prelocked Trigger to initiate the CHA cycle between hairpin H2-modified Fe-Co-MOFs and hairpin H1-tethered magnetic nanoparticles to form complexes. After magnetic separation, the colorimetric signal of the supernatant in the presence of TMB and H2O2 is inversely proportional to the target contents. Under optimal conditions, this biosensor enables the analysis of AFB1 with a limit of detection of 6.44 pg/mL, and high selectivity and satisfactory recovery in real samples are obtained. On the other hand, Fe-Co-MOFs with remarkable Fenton-like catalytic degradation performance for organic contaminants are further used for the detoxification of AFB1 after colorimetric detection. The AFB1 is almost completely removed within 120 min. Overall, the introduction of CHA improves the sensing sensitivity; efficient postcolorimetric-detection degradation of AFB1 reduces the secondary contamination and risk to the experimental environment and operators. This strategy is expected to provide ideas for designing other multifunctional platforms to integrate the detection and degradation of various hazards.

A novel framework based on two-stage multi-view feature optimization and improved support vector data description for aeroengine bearing early fault detection

Early fault detection is crucial to avoid catastrophic flight accidents caused by unplanned downtime of equipment. Aimed at the shortcomings of feature selection and early fault detection, this paper proposes a method combining two-stage multi-view feature optimization and improved support vector data description for aeroengine bearing early fault detection. First, a comprehensive evaluation index is constructed via combining monotonicity, correlation, robustness index and entropy weight method to be used for initial screening sensitive degradation features from multi-view candidate degradation feature. After that, the hierarchical clustering algorithm and local preserving projection algorithm is introduced to realize sensitive degradation features clustering and dimensionality reduction. On this basis, the Euclidean distance sample reduction and the sparrow search algorithm is utilized to complete the training sample selection and model parameter optimization of different clusters and further use the verification samples to filter the optimal features and model. Finally, based on the optimal degradation features and models, a fusion performance degradation index is built to achieve intelligent detection of early fault. Comparisons with some existing fault detection methods, the proposed method improves degradation trend sensibility and demonstrates potential of good early fault detection engineering applications.

Identification of priority areas for territorial space ecological restoration in arid area of Northwest China: A case study of Zhangye City in Heihe River basin.

Determining priority areas for territorial ecological restoration in the arid region of Northwest China based on the holistic protection and systematic governance is an important measure to build solid national ecological security barrier and promote the construction of territorial ecological civilization. Taking Zhangye City, a typical arid area city in Northwest China, as an example, we constructed the research framework of "ecological network-ecological sensitivities-ecological degradation" from two aspects of internal defects and external threats of ecological networks by using circuit theory and assessment methods of ecological service function importance, ecological sensitivity, and ecological degradation. We then identified the priority areas of territorial ecological restoration in northwest arid region and put forward the restoration strategies. The results showed that the priority areas of ecological restoration in Zhangye City were concentrated in the artificial shelterbelt along rivers and the plain-desert-oasis transition zone with fragile ecology and strong human interference. The ecological network of the study area included 39 ecological sources and 99 ecological corridors, and the highly sensitive and degraded areas were 1595.40 and 6.65 km2. Based on the internal defects and external threats of the ecological network, we identified 31 ecological pinch points, 7 obstacle points, and 753.56 km2 ecological source areas in the territorial spatial ecological restoration priority area. These areas were related to the connectivity of the ecological network internally and the stability maintenance of the ecosystem outwards, and were the areas to restoration in the future. Following the concept of overall protection and system restoration of territorial space, we put forward the idea of territorial space restoration by integrating internal defects and external threats of ecological network, which could provide scientific decision-making basis for comprehensive ecosystem management and territorial optimization of Zhangye City.

Sense and Shoot: Multifunctional CaO2-loaded Cu-MOF nanosheets for integrated fluorescence detection and fenton-like degradation of tetracycline

Simultaneous accomplishment of sensitive detection and efficient degradation of antibiotics residues exposed in the aqueous environments has proved to be a difficult endeavor. Here, multifunctional composite CaO2-loaded Cu-MOF nanosheets (CaO2@Cu-MOF NSs) was elaborately designed and synthesized. Triggered by H+, the composite is not only capable of producing Ca2+ as the signal factor for tetracycline (TC) detection by activating the fluorescence emission of calcein, but also capable of self-supplying H2O2 and Cu2+ to construct a novel Fenton-like oxidation and O2 activation system for TC degradation based on Cu2+/Cu+ cycle. Under the synergy of target cycling and nano-enhancement, the sensing system exhibited great TC detection performance with a linear range of 0.001 to 100 ng mL−1 and detection limit of 11.8 fg mL−1. At the same time, the degradation system exhibited favorable degradation performance under the systematic action of Fenton-like and O2-activated oxidation. Nearly 80 % of the TC residues could be degraded within 10 min, and more than 95 % within 60 min. The constructed system was successfully applied to detect and degrade exposed TC in actual water samples in an integrated manner, demonstrating great promise for practical applications.

A novel bio-template route to synthesize enzyme-immobilized MOF/LDH tubular magnetic micromotors and their application in water treatment

A ramie-templated micromotor loaded with a natural HRP enzyme was constructed, which had a potent peroxidase-like activity driven by decomposition of H2O2 for sensitive detection and degradation of catechol.

Glucose microenvironment sensitive degradation of arginine modified calcium sulfate reinforced poly(lactide-co-glycolide) composite scaffolds.

Poly(lactide-co-glycolide) (PLGA) and calcium sulfate composites are promising biodegradable biomaterials but are still challenging to use in people with high levels of blood glucose or diabetes. To date, the influence of glucose on their degradation has not yet been elucidated and thus calls for more research attention. Herein, a novel calcium sulfate whisker with L-arginine was used to effectively tune its crystal morphology and was employed as a reinforced phase to construct the PLGA-based composite scaffolds (ArgCSH/PLGA) with a sleeve porous structure. ArgCSH/PLGA showed excellent elastic modulus and strength in the compression and bending models. Moreover, an in vitro immersion test showed that ArgCSH/PLGA possessed degradation and redeposition behaviors sensitive to glucose concentration, and the adsorbed Arg played a crucial role in the degradation process. The subsequent cell functional evaluation showed that ArgCSH could effectively protect cells from damage caused by AGEs and promote osteogenic differentiation. The corresponding degradation products of ArgCSH/PLGA displayed the ability to regulate osteoblast bone differentiation and accelerate matrix mineralization. These findings provide new insights into the interaction between biomaterials and the physiological environment, which may be useful in expanding the targeted choice of efficient bone graft biodegradable materials for diabetic osteoporosis.

Fusing sensitive degradation features with uncertainty analysis for RUL prediction of rotating machines

Recently, deep learning technology-based neural networks have been adopted for remaining useful life (RUL) prediction of rotating machines. However, there are still some shortcomings: (1) an individual degradation feature cannot sufficiently represent the degradation process, which has an adverse impact on the accuracy of prediction results; (2) most recurrent neural network-based prediction methods have difficulty in quantifying the uncertainty of the forecast results. In this paper, a fusing sensitive degradation features with uncertainty analysis for RUL prediction of rotating machines is proposed. Firstly, the statistical features contained in the vibration signal used to monitor the degradation of rotating equipment are extracted to construct the original feature set. Then, the weight coefficients of the monotonicity, correlation and robustness criteria are determined by the self-adjusting analytic hierarchy process. The sensitive features that describe the degradation process are selected from among the statistical features. Furthermore, the sensitive features are fed into residual networks and gated recurrent unit, and the spatial and temporal correlation of the features are considered to establish the health index (HI). Finally, the fitted HI is input into a Gaussian process regression model, and the prediction results with confidence intervals are obtained. To verify the effectiveness and superiority of the proposed method, two public bearing datasets and three model methods are used for comparative experiments.