bluuebunny/crossref_metadata_2025 huggingface dataset:
Targeting Potential of Innate Lymphoid Cells in Melanoma and Other Cancers
Authors: Seo Hobin , Verma Amisha , Kinzel Megan , Huang Qiutong , Mahoney Douglas J. , Jacquelot Nicolas
Published: July 2023

Reinvigorating the killing function of tumor-infiltrating immune cells through the targeting of regulatory molecules expressed on lymphocytes has markedly improved the prognosis of cancer patients, particularly in melanoma. While initially thought to solely strengthen adaptive T lymphocyte anti-tumor activity, recent investigations suggest that other immune cell subsets, particularly tissue-resident innate lymphoid cells (ILCs), may benefit from immunotherapy treatment. Here, we describe the recent findings showing immune checkpoint expression on tissue-resident and tumor-infiltrating ILCs and how their effector function is modulated by checkpoint blockade-based therapies in cancer. We discuss the therapeutic potential of ILCs beyond the classical PD-1 and CTLA-4 regulatory molecules, exploring other possibilities to manipulate ILC effector function to further impede tumor growth and quench disease progression.
Next-Generation Nanomedicine Approaches for the Management of Retinal Diseases
Authors: Mahaling Binapani , Low Shermaine W. Y. , Ch Sanjay , Addi Utkarsh R. , Ahmad Baseer , Connor Thomas B. , Mohan Rajiv R. , Biswas Swati , Chaurasia Shyam S.
Published: July 2023

Retinal diseases are one of the leading causes of blindness globally. The mainstay treatments for these blinding diseases are laser photocoagulation, vitrectomy, and repeated intravitreal injections of anti-vascular endothelial growth factor (VEGF) or steroids. Unfortunately, these therapies are associated with ocular complications like inflammation, elevated intraocular pressure, retinal detachment, endophthalmitis, and vitreous hemorrhage. Recent advances in nanomedicine seek to curtail these limitations, overcoming ocular barriers by developing non-invasive or minimally invasive delivery modalities. These modalities include delivering therapeutics to specific cellular targets in the retina, providing sustained delivery of drugs to avoid repeated intravitreal injections, and acting as a scaffold for neural tissue regeneration. These next-generation nanomedicine approaches could potentially revolutionize the treatment landscape of retinal diseases. This review describes the availability and limitations of current treatment strategies and highlights insights into the advancement of future approaches using next-generation nanomedicines to manage retinal diseases.
An In Vivo Electroencephalographic Analysis of the Effect of Riluzole against Limbic and Absence Seizure and Comparison with Glutamate Antagonists
Authors: Citraro Rita , Bosco Francesca , Di Gennaro Gianfranco , Tallarico Martina , Guarnieri Lorenza , Gallelli Luca , Rania Vincenzo , Siniscalchi Antonio , De Sarro Giovambattista , Leo Antonio
Published: July 2023

Background: Riluzole (RLZ) has demonstrated neuroprotective effects in several neurological disorders. These neuroprotective effects seem to be mainly due to its ability to inhibit the excitatory glutamatergic neurotransmission, acting on different targets located both at the presynaptic and postsynaptic levels. Methods: In the present study, we evaluated the effects of Riluzole (RLZ) against limbic seizures, induced by AMPA, kainate, and NMDA receptor agonists in Sprague–Dawley rats, and in a well-validated genetic model of absence epilepsy, the WAG/Rij rat. Furthermore, in this latter model, we also studied the effect of RLZ in co-administration with the competitive NMDA receptor antagonist, CPP, or the non-competitive AMPA receptor antagonist, THIQ-10c, on spike-wave discharges (SWDs) in WAG/Rij rats, to understand the potential involvement of AMPA and NMDA receptors in the anti-absence effect of RLZ. Results: In Sprague–Dawley rats, RLZ pretreatment significantly reduced the limbic seizure severity induced by glutamatergic agonists, suggesting an antagonism of RLZ mainly on NMDA rather than non-NMDA receptors. RLZ also reduced SWD parameters in WAG/Rij rats. Interestingly, the co-administration of RLZ with CPP did not increase the anti-absence activity of RLZ in this model, advocating a competitive effect on the NMDA receptor. In contrast, the co-administration of RLZ with THIQ-10c induced an additive effect against absence seizure in WAG/Rij rats. Conclusions: these results suggest that the antiepileptic effects of RLZ, in both seizure models, can be mainly due to the antagonism of the NMDA glutamatergic receptors.
Twisted Silica Few-Mode Hollow GeO2-Doped Ring-Core Microstructured Optical Fiber
Authors: Bourdine Anton V. , Demidov Vladimir V. , Ter-Nersesyants Egishe V. , Pchelkin Grigori A. , Shurupov Dmitriy N. , Khokhlov Alexander V. , Matrosova Alexandra S. , Kashin Andrey I. , Bureev Sergei V. , Dashkov Michael V. , Evtushenko Alexander S. , Zaitseva Elena S. , Gizatulin Azat R. , Meshkov Ivan K. , Dyavangoudar Amogh A. , Saharia Ankur , Tiwari Manish , Vasilets Alexander A. , Elagin Vasiliy S. , Singh Ghanshyam , Dukelskii Konstantin V.
Published: July 2023

This work presents the first instance of a silica few-mode microstructured optical fiber (MOF) being successfully fabricated with a hollow GeO2-doped ring core and by strongly inducing twisting up to 790 revolutions per meter. Some technological issues that occurred during the manufacturing of the GeO2-doped supporting elements for the large hollow cores are also described, which complicated the spinning of the MOFs discussed above. We also provide the results of the tests performed for the pilot samples—designed and manufactured using the untwisted and twisted MOFs described above—which were characterized by an outer diameter of 65 µm, a hollow ring core with an inner diameter of 30.5 µm, under a wall thickness of 1.7 µm, and a refractive index difference of Δn = 0.030. Moreover, their geometrical parameters, basic transmission characteristics, and the measurements of the far-field laser beam profile patterns are also provided.
Preparation of Organic-Inorganic Phosphorus-Nitrogen-Based Flame Retardants and Their Application to Plywood
Authors: Deng Chao , Ji Yu , Zhu Meng , Liang Yuqing , Jian Hao , Yan Zhichun , Wen Mingyu , Park Heejun
Published: July 2023

The combustibility of wood can be improved by physical and chemical means, thus expanding the use of wood products. In this study, two novel phosphorus-nitrogen flame retardants (UCPR and MCPR) were developed, and the intercalated modified layered double hydroxides (LDH) thereof were designated as UCPR-LDH and MCPR-LDH. By impregnating poplar veneer with UCPR-LDH and MCPR-LDH solutions, the study investigated the effects of different concentrations (1%, 5%, 10%), processes (vacuum-pressure impregnation, room temperature impregnation, normal-pressure impregnation), and impregnation times (2 h, 3 h, 24 h, 48 h) on the weight-gain rate of veneer. The optimal process was then selected for preparing formaldehyde-free three-layer plywood. Nuclear magnetic resonance (NMR) and Fourier transform infrared (FTIR) were used to characterize the UCPR and MCPR. Meanwhile, gel-permeation chromatography (GPC) demonstrated that the molecular weight of the synthesized flame retardants increased as their molecular distribution became more uniform. The impregnation process was performed at normal temperature and pressure for 48 h at a 5% flame retardant concentration. Results from cone calorimetry indicate that the UCPR-LDH plywood exhibits a peak heat release rate that is 30.43% lower than that of the control group, demonstrating superior thermal barrier performance. The smoke emission of the MCPR-LDH plywood was reduced by 33.62% compared to the control group, indicating superior smoke suppression performance. This method presents a viable approach for synthesizing organic-inorganic flame retardants.
Facile Synthesis of Nitrogen-Rich Porous Carbon/NiMn Hybrids Using Efficient Water-Splitting Reaction
Authors: Periyasamy Thirukumaran , Asrafali Shakila Parveen , Kim Seong-Cheol , Lee Jaewoong
Published: July 2023

Proper design of multifunctional electrocatalyst that are abundantly available on earth, cost-effective and possess excellent activity and electrochemical stability towards oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) are required for effective hydrogen generation from water-splitting reaction. In this context, the work herein reports the fabrication of nitrogen-rich porous carbon (NRPC) along with the inclusion of non-noble metal-based catalyst, adopting a simple and scalable methodology. NRPC containing nitrogen and oxygen atoms were synthesized from polybenzoxazine (Pbz) source, and non-noble metal(s) are inserted into the porous carbon surface using hydrothermal process. The structure formation and electrocatalytic activity of neat NRPC and monometallic and bimetallic inclusions (NRPC/Mn, NRPC/Ni and NRPC/NiMn) were analyzed using XRD, Raman, XPS, BET, SEM, TEM and electrochemical measurements. The formation of hierarchical 3D flower-like morphology for NRPC/NiMn was observed in SEM and TEM analyses. Especially, NRPC/NiMn proves to be an efficient electrocatalyst providing an overpotential of 370 mV towards OER and an overpotential of 136 mV towards HER. Moreover, it also shows a lowest Tafel slope of 64 mV dec−1 and exhibits excellent electrochemical stability up to 20 h. The synergistic effect produced by NRPC and bimetallic compounds increases the number of active sites at the electrode/electrolyte interface and thus speeds up the OER process.
Synchronous Improvement of Mechanical and Damping Properties of Structural Damping Composites with Polyetherimide Non-Woven Fabric Interlayers Loaded with Polydopamine and Carbon Nanotubes
Authors: Zhou Shihao , Lai Yuanchang , Ma Junchi , Liu Bin , Ni Nannan , Dai Feng , Xu Yahong , Wang Zhaodi , Yang Xin
Published: July 2023

Structural damping composites exhibit considerable potential in aerospace and other fields due to their excellent damping and vibration reduction performance, as well as their structural carrying capacity. However, conventional structural damping composite materials generally do not combine excellent mechanical and damping properties at the same time, which makes it difficult for them to meet the practical demand in engineering. In this paper, polyetherimide (PEI) non-woven fabric interlayer materials loaded with quantified polydopamine (PDA) and carboxylated multi-walled carbon nanotubes (MWCNTs-COOH) were used to prepare carbon fiber-reinforced bismaleimide composites through the co-curing process. The mechanical and damping properties of the composites were systematically studied. The results demonstrate that PEI non-woven fabric interlayers loaded with PDA and MWCNTs-COOH can synchronously improve the mechanical and damping properties of the co-cured composites. The incorporation of carbon nanotubes and polydopamine during the co-curing process synergistically improves the flexural strength, flexural modulus, interlaminar shear strength, and impact fracture toughness of the composites. Most importantly, damping properties show an increase of 45.0% in the loss factor of the co-cured composites. Moreover, the reinforcement mechanism was investigated using the optical microscopy and scanning electron microscopy, which indicated that the PEI interlayers loaded with carbon nanotubes and polydopamine form a rich resin area between the layers of the composites.
Combined Effect of Citric Acid and Polyphenol-Rich Grape Seed Extract towards Bioactive Smart Food Packaging Systems
Authors: Pažarauskaitė Akvilė , Noriega Fernández Estefanía , Sone Izumi , Sivertsvik Morten , Sharmin Nusrat
Published: July 2023

Alginate films (2% w·v−1) were prepared with varying concentrations (5–20% w/w) of citric acid and aqueous grape seed extract (GSE) filtrate (11.66 ± 1.32 g GAE/L) using the solvent-evaporation method. Crosslinking alginate via ester bonds (FTIR analysis) with citric acid up to 10% (w/w) led to a 33% increase in tensile strength, a 34% reduction in water vapor transmission rate (WVTR), and had no impact on elongation at break. Crosslinking alginate with citric acid in the presence of GSE increased the tensile strength by 17%, decreased WVTR by 21%, and significantly improved DPPH scavenging activity. Moreover, after incubation for 24 h at 37 °C, the film-forming solutions exhibited increased antimicrobial activity, resulting in 0.5- and 2.5-log reductions for Escherichia coli and Staphylococcus aureus, respectively, compared to the values obtained without the addition of GSE. The stronger inhibitory effect observed against Gram-positive bacteria can be attributed to the unique composition and structure of their cell walls, which creates a barrier that restricts the penetration of polyphenols into the cells. The pH adjustment of the GSE film-forming solution from 2.0 to 10.0 shifted the UV/VIS absorption spectra, resulting in a colour change from yellow to red. The findings of this study have showcased the potential of combining GSE and citric acid to enhance the functionality and bioactivity of alginate films for applications in smart food packaging.
Adducts of Carbon Black with a Biosourced Janus Molecule for Elastomeric Composites with Lower Dissipation of Energy
Authors: Magaletti Federica , Margani Fatima , Monti Alessandro , Dezyani Roshanak , Prioglio Gea , Giese Ulrich , Barbera Vincenzina , Galimberti Maurizio
Published: July 2023

Elastomer composites with low hysteresis are of great importance for sustainable development, as they find application in billions of tires. For these composites, a filler such as silica, able to establish a chemical bond with the elastomer chains, is used, in spite of its technical drawbacks. In this work, a furnace carbon black (CB) functionalized with polar groups was used in replacement of silica, obtaining lower hysteresis. CBN326 was functionalized with 2-(2,5-dimethyl-1H-pyrrol-1-yl)-1,3-propanediol (serinol pyrrole, SP), and samples of CB/SP adducts were prepared with different SP content, ranging from four to seven parts per hundred carbon (phc). The entire process, from the synthesis of SP to the preparation of the CB/SP adduct, was characterized by a yield close to 80%. The functionalization did not alter the bulk structure of CB. Composites were prepared, based on diene rubbers—poly(1,4-cis-isoprene) from Hevea Brasiliensis and poly(1,4-cis-butadiene) in a first study and synthetic poly(1,4-cis-isoprene) in a second study—and were crosslinked with a sulfur-based system. A CB/silica hybrid filler system (30/35 parts) was used and the partial replacement (66% by volume) of silica with CB/SP was performed. The composites with CB/SP exhibited more efficient crosslinking, a lower Payne effect and higher dynamic rigidity, for all the SP content, with the effect of the functionalized CB consistently increasing the amount of SP. Lower hysteresis was obtained for the composites with CB/SP. A CB/SP adduct with approximately 6 phc of SP, used in place of silica, resulted in a reduction in ΔG′/G′ of more than 10% and an increase in E’ at 70 °C and in σ300 in tensile measurements of about 35% and 30%, respectively. The results of this work increase the degrees of freedom for preparing elastomer composites with low hysteresis, allowing for the use of either silica or CB as filler, with a potentially great impact on an industrial scale.
Synthesis and Characterization of Core–Double-Shell-Structured PVDF-grafted-BaTiO3/P(VDF-co-HFP) Nanocomposite Films
Authors: Bouharras Fatima Ezzahra , Atlas Salima , Capaccioli Simone , Labardi Massimiliano , Hajlane Abdelghani , Ameduri Bruno , Raihane Mustapha
Published: July 2023

Core–double-shell-structured nanocomposite films consisting of polyvinylidene fluoride-grafted-barium titanate (PVDF-g-BT) incorporated into a P(VDF-co-hexafluoropropylene (HFP)) copolymer matrix were produced via a solution mixing method for energy storage applications. The resulting films were thoroughly investigated via spectroscopic, thermal, and morphological analyses. Thermogravimetric data provided an enhancement of the thermal stability, while differential scanning calorimetry indicated an increase in the crystallinity of the films after the addition of PVDF-g-BT. Moreover, broadband dielectric spectroscopy revealed three dielectric processes, namely, glass–rubber relaxation (αa), relaxation associated with the polymer crystalline phase (αc), and slower relaxation in the nanocomposites resulting from the accumulation of charge on the interface between the PVDF-g-BT filler and the P(VDF-co-HFP) matrix. The dependence of the dielectric constant from the composition was analyzed, and we found that the highest permittivity enhancement was obtained by the highest concentration filler added to the largest concentration of P(VDF-co-HFP). Mechanical analysis revealed an improvement in Young’s modulus for all nanocomposites versus pristine P(VDF-co-HFP), confirming the uniformity of the distribution of the PVDF-g-BT nanocomposite with a strong interaction with the copolymer matrix, as also evidenced via scanning electron microscopy. The suggested system is promising for use in high-energy-density storage devices as supercapacitors.
Study on the Applicability of Saturated Hydrocarbon Parameters in the Evaluation of Lacustrine Source Rocks and Oils Based on Thermal Simulation Experiments
Authors: Chen Zhijun , Zhang Yaxiong , Wen Zhigang , He Yonghong , Zhang Chunming , Zhang Ge , Han Changchun , Li Ziliang
Published: July 2023

Saturated hydrocarbons are widely used in the valuation of source rocks and oils, but the applicability of related parameters has received less attention. Based on the thermal simulation experiments on Mesozoic source rocks in the Yingen-Ejinaqi Basin, and the GC-MS analysis of the saturated hydrocarbon fractions of the expelled oils and extracts from solid residues, the applicability of the parameters related to lacustrine source rocks and oil were discussed. The results indicated that: Controlled by thermal degradation, both the relative abundance of the tricyclic terpenoids in terpenoids and the pregnane (including L pregnane) in steroids increased with the increase in maturity. Maturity had little effect on some environmental parameters of lacustrine source rocks and oils, such as Pr/Ph and gammacerane index, they were still effective even at the high-over maturity stage. But maturity had a significant influence on the method of using saturated hydrocarbons to identify the source of organic matter, because only at the thermal stage of Ro < 1.45%, might it effectively identify the source of organic matter by using the dominant peak of n-alkanes method and the relative abundance of C27–C29 steranes method. Most saturated hydrocarbon maturity parameters had their valid scope of application, such as C29 20S/(20S + 20R) steranes, C29αββ/(ααα + αββ) steranes and C31αβ22S/(22S + 22R) homohopanes were only effective when the Ro value was below 2.06%, for the parameter’s value would be “inverted” in the stage of over-maturity (Ro > 2.06%). However, the parameter Ts/(Ts + Tm) was effective in the whole thermal evolution process, reflecting good applicability. This study clarifies the validity of the application of commonly used saturated hydrocarbon parameters, and it can provide some reference for relevant studies.
Mathematical Investigation of Heat Transfer Characteristics and Parameter Optimization of Integral Rolled Spiral Finned Tube Bundle Heat Exchangers
Authors: Zhang Danfeng , Wu Wenchang , Zhao Liang , Dong Hui
Published: July 2023

In this study, the effects of fin tip thickness and fin root thickness of integral rolled spiral finned tube bundles on flow resistance, heat transfer performance and heat transfer and flow exergy destruction were investigated via mathematical simulation. The correlations between heat transfer and flow resistance performance were fitted with dimensionless numbers. The optimized parameters with performance evaluation criteria (PEC) as the objective were obtained using methods involving computational fluid dynamics and machine learning. The results show the effects of fin tip thickness and fin root thickness on the Nusselt number (Nu), Euler number (Eu), PEC, heat transfer exergy destruction (ExT) and flow exergy destruction (ExP) as obtained via mathematical simulation. A new mathematical correlation is proposed for predicting the Nu and Eu of integral rolled spiral finned tube bundles. Among the four optimization models tested, the random forest regression algorithm was the most accurate algorithm for PEC prediction models. In the studied range, the optimal parameters were a fin tip thickness of 2 mm and a fin root thickness of 3.5 mm. Compared with the initial parameters, when the Reynolds number was 20,380, the PEC increased by 2.53%, the ExP increased by 2.37% and the ExT decreased by 7.96%.
Effect of Jet Nozzle Position on Mixing Time in Large Tanks
Authors: Oluwadero Timothy Ayodeji , Xuereb Catherine , Aubin Joelle , Poux Martine
Published: July 2023

The present investigation focuses on the impact of jet nozzle orientation on mixing time in a cylindrical tank. The aim is to identify nozzle positions that improve mixing performance and to elucidate the governing parameters that influence it. A water tank was employed for the experiment. The vertical inclination angle (α) and the horizontal inclination angle (β) of the jet nozzle determined the nozzle positions. Mixing time was determined using an inert tracer and spectrophotometry measurements. The findings show that the mixing time is significantly influenced by the position of the jet nozzle position. The accuracy of existing jet turbulence and the circulation models for the prediction of mixing time was evaluated for the different nozzle positions. Our results indicate that both models provide accurate predictions for the conventional centrally aligned (β = 0°), upward-pointing jet nozzle positions only (α > 0). For the other nozzle positions where β > 0° and at varying α, the data follow the same trends as the jet turbulence and circulation models; however, the proportionality constants vary. Shorter mixing times can be attributed principally to longer jet path lengths and therefore higher fluid entrainment and circulation as well as higher dissipation rates per jet length squared. However, it is suspected that the three-dimensional nature of the flow pattern generated in the tank also plays a non-negligible role since mixing is hindered when the nozzle points more towards the tank wall.
Paleoenvironmental Conditions and Shale Oil Potential of the Carboniferous Ha’erjiawu Formation in the Santanghu Basin, NW China
Authors: Zhang Shaohua , Liu Chiyang , Fan Zhiqiang , Liang Hao , Gao Jianrong , Song Hui , Dang Wei , Zhang Long , Gao Yaning
Published: July 2023

The Carboniferous Ha’erjiawu Formation in the Santanghu Basin represents a significant potential target for shale oil exploration, yet its characteristics remain largely unknown. This study utilizes a combination of elemental and organic geochemical analyses to investigate the paleoenvironmental conditions and shale oil potential of the Carboniferous Ha’erjiawu Formation black shales within the Santanghu Basin. The results suggest that the Ha’erjiawu Formation black shales were deposited in water columns with low salinity and dysoxic conditions, as indicated by paleosalinity and redox proxies such as Rb/K, B/Ga, B content, V/Cr, V/(V + Ni), V/Al, and Mo/Al. Furthermore, the climatic proxies (Ga/Rb, Sr/Cu and K2O/Al2O3) indicate that the Santanghu Basin underwent a warm-humid/cold-dry oscillating climate during the deposition of the Ha’erjiawu Formation black shales, potentially influenced by synsedimentary volcanic activity or the Late Paleozoic glaciation. The organic geochemical analyses have revealed that the Ha’erjiawu Formation black shales are rich in type II kerogen, which is in the early mature to mature stage, indicating a significant potential for oil generation. However, there is considerable variation in the oil content of the analyzed samples, with only a few containing movable oil. Given the high abundance of brittle minerals within the Ha’erjiawu Formation black shales, it will be indispensable to meticulously evaluate and identify intervals exhibiting abundant movable oil for successful shale oil exploration and development within this geological unit.
Accurate Standard Errors in Multilevel Modeling with Heteroscedasticity: A Computationally More Efficient Jackknife Technique
Authors: Zitzmann Steffen , Weirich Sebastian , Hecht Martin
Published: July 2023

In random-effects models, hierarchical linear models, or multilevel models, it is typically assumed that the variances within higher-level units are homoscedastic, meaning that they are equal across these units. However, this assumption is often violated in research. Depending on the degree of violation, this can lead to biased standard errors of higher-level parameters and thus to incorrect inferences. In this article, we describe a resampling technique for obtaining standard errors—Zitzmann’s jackknife. We conducted a Monte Carlo simulation study to compare the technique with the commonly used delete-1 jackknife, the robust standard error in Mplus, and a modified version of the commonly used delete-1 jackknife. Findings revealed that the resampling techniques clearly outperformed the robust standard error in rather small samples with high levels of heteroscedasticity. Moreover, Zitzmann’s jackknife tended to perform somewhat better than the two versions of the delete-1 jackknife and was much faster.
The Hegemonic Character of Techno-Functional Neo-Immanentism and Its Relationship with Culture Wars
Authors: Sánchez Capdequí Celso , Gil-Gimeno Javier , Echeverría Esparza Pablo
Published: July 2023

This paper analyzes the social processes that have led to the consolidation of a technocratic secular order and the type of cultural struggle that has made this possible. To this end, it first proposes a reconstruction of the technocratic consciousness in the course of the secularization process that culminates in the technological determinism or technological solutionism of the social present; then, the analysis focuses on the neo-immanentist tendency of techno-functionalism, in which the secular context and the text of secularization become one and deplete a social explanation; thirdly, it reflects on and deals with the open nature of secular life, in which context does not determine social texts (inter-actions) and opens the way to the existence of different life options that compete with each other and even turn on—rebel against—institutional design. This reflection, then, focuses on the specific features of the culture wars in Western Judeo-Christian culture and its globalizing tendency. Finally, the document closes with a conclusion that analyzes the road travelled and introduces the new challenges arising from the arguments presented.
The Radar Signal Processor of the First Romanian Space Surveillance Radar
Authors: Bîră Călin , Ionescu Liviu , Rusu-Casandra Alexandru
Published: July 2023

This paper describes the work for the radar signal processor, the core of the Cheia space surveillance radar. It presents the basic operation, the requirements and the achieved processing performance together with a description of optimizations both in terms of signal-to-noise ratio and in terms of software processing. The Cheia Radar is financed by the European Space Agency and will be used for the tracking of low Earth orbit objects and for refining the international catalogs of space objects.
Channel Activity Remote Sensing Retrieval Model: A Case Study of the Lower Yellow River
Authors: Wu Taixia , Xu Zenan , Chen Ran , Wang Shudong , Li Tao
Published: July 2023

Meandering channel migration is a widespread phenomenon in rivers all around the world. Channel activity, which reflects the rate of change of a meandering channel, is calculated by averaging lateral channel migration. Channel migration can create new channels and abandon old ones, with effects on the natural environment. Floods can even lead to excessive rates of channel migration, which can threaten cities or farmland. Remote sensing can detect the spatial and temporal dynamic characteristics of the river channel, taking into account both spatial and temporal resolution, and can help in planning for the safety of the river channel in advance. Previous studies on river channels have suffered from a low accuracy of data, low level of automation, and subjectivity. To overcome these limitations, we propose a channel activity remote sensing retrieval model (CARSM) in this paper. CARSM extracts water using the modified normalized difference water index (MNDWI) combined with Otsu’s method on the Google Earth Engine (GEE) platform, then extracts the channel centerlines via water mask maps using RivWidthCloud, and finally calculates channel activity based on the geometric relationship of the channel centerlines. With more objective extraction results, CARSM can guarantee more than 95% accuracy of channel activity and its high degree of automation can save a lot of labor costs. We use Landsat images to monitor the channel of the Lower Yellow River and calculate the overall and segmental channel activity separately. Our results show that the overall channel activity of the Lower Yellow River has gradually decreased between 1990 and 2020, with decreases of 33.04% and 41.06%, respectively. Analysis of channel activity reveals that the water sediment pattern of the Lower Yellow River changed from siltation to scouring after the completion of Xiaolangdi Reservoir, and the Lower Yellow River is gradually becoming stable.
Assessing Models of Sea Level Rise and Mean Sea Surface with Sentinel-3B and Jason-3 Altimeter Data near Taiwan: Impacts of Data Quality and Length
Authors: Hsiao Yu-Shen , Hwang Cheinway , Chen Te-Wei , Cho Yu-Hsuan
Published: July 2023

Studying the local sea level rise (SLR) is vital for coastal sustainability and resilience amid climate change. Using the latest altimeter data from the Sentinel-3B (S3B) and Jason-3 (J3) missions, we investigated the regional variability and accuracy of SLR rates around Taiwan and evaluated the accuracies of three mean sea surface (MSS) models: NCTUMSS, CLS15, and DTU18. NCTUMSS is a regional model for defining the new depth datum of Taiwan. The least-squares method with outlier removal was used to compute the along-track SLRs and MSS heights from S3B and J3. Our results show that the SLR rates around Taiwan in the recent 3–6 years from S3B and J3 were 2.0–3.0 mm/year higher than the global rate of 3.3 mm/year. Positive SLR rates were observed in most waters around Taiwan, but negative rates occurred in some parts of the Taiwan Strait. Short-term SLR rates from S3B and J3 were significantly different from the long-term rates determined using altimeter data from the TOPEX/POSEIDON (TP), Jason-1, Jason-2, and J3 missions from 1992.96 to 2021.92. The comparison between the along-track MSS heights from S3B and J3 and the modeled MSS heights showed that CLS15 had the highest accuracy. The DTU18 model exhibited lower sea surface heights near Penghu in the Taiwan Strait compared with CLS15 and NCTUMSS. The NCTUMSS model incorporates tide gauge measurements and Taiwan’s hybrid geoid for a smooth transition from ocean to land. It was concluded that the SLR rates around Taiwan were not uniform, and the rates provided by the three global models, as well as the along-track S3B and J3 altimeter data, suffered from problems like limited spatial resolutions and accuracies, which originated from limited altimeter data qualities and record lengths. One must be cautious about the accuracy of an MSS model for constructing a depth datum and the accuracy of an SLR model for mitigating SLR-induced hazards. We recommend updating the MSS model around Taiwan every 7 years to ensure a 2 cm accuracy requirement, considering the average SLR rate of 3.3 mm/year around Taiwan. Short-term data reflects recent sea level rise but lacks accuracy, while the long-term sea level record may be more precise but may not capture recent rates, necessitating a comprehensive approach that considers both factors for producing accurate assessments and the planning of sea level rise impacts.
Faster and Better: A Lightweight Transformer Network for Remote Sensing Scene Classification
Authors: Huang Xinyan , Liu Fang , Cui Yuanhao , Chen Puhua , Li Lingling , Li Pengfang
Published: July 2023

Remote sensing (RS) scene classification has received considerable attention due to its wide applications in the RS community. Many methods based on convolutional neural networks (CNNs) have been proposed to classify complex RS scenes, but they cannot fully capture the context in RS images because of the lack of long-range dependencies (the dependency relationship between two distant elements). Recently, some researchers fine-tuned the large pretrained vision transformer (ViT) on small RS datasets to extract long-range dependencies effectively in RS scenes. However, it usually takes more time to fine-tune the ViT on account of high computational complexity. The lack of good local feature representation in the ViT limits classification performance improvement. To this end, we propose a lightweight transformer network (LTNet) for RS scene classification. First, a multi-level group convolution (MLGC) module is presented. It enriches the diversity of local features and requires a lower computational cost by co-representing multi-level and multi-group features in a single module. Then, based on the MLGC module, a lightweight transformer block, LightFormer, was designed to capture global dependencies with fewer computing resources. Finally, the LTNet was built using the MLGC and LightFormer. The experiments of fine-tuning the LTNet on four RS scene classification datasets demonstrate that the proposed network achieves a competitive classification performance under less training time.
Monitoring and Analyzing the Effectiveness of the Effective Refuge Area of Emergency Shelters by Using Remote Sensing: A Case Study of Beijing’s Fifth Ring Road
Authors: You Di , Wang Shixin , Wang Futao , Zhou Yi , Wang Zhenqing , Wang Yanchao , Wang Jingming , Xiong Yibing , Ji Jianwan
Published: July 2023

The effective refuge area is a key indicator in the study of emergency shelters. Accurately extracting the effective refuge area and analyzing the effectiveness of emergency shelters are of great significance for site selection, spatial distribution, and the evaluation of suitability. Beijing is one of only three capitals in the world located in a high-seismic-intensity zone of magnitude 8. The fast and accurate monitoring of effective refuge areas and an analysis of the effectiveness of emergency shelters are conducive to evacuation planning and disaster prevention and mitigation, and they promote the construction of a resilient city. However, the extraction of effective refuge areas in existing studies is not only a time-consuming and labor-intensive task but also has accuracy and efficiency problems, resulting in less precise validity analyses. In this paper, a remote sensing monitoring technology system for the effective refuge areas of emergency shelters is proposed based on multi-source data. Different methods were used to extract various land features, such as buildings and collapsed areas, water, dense areas of understory vegetation, and steep slope areas that cannot be evacuated, to obtain the effective refuge area at a detailed scale, in combination with the service radius of emergency shelters, the population distribution, and the actual road network, the criteria for effectiveness analysis were established for the effective open space ratio, capacity, per capita accessible effective refuge area, and population allocation gap. Taking the area within the Fifth Ring Road of Beijing as an example, the effectiveness of emergency shelters was analyzed at both the whole scale and a local scale. The results show that the effective refuge areas of different emergency shelters in Beijing vary significantly, with the smallest effective refuge area being located in Rings 2–3 and the largest one being located in Rings 4–5; between different regions, there are differences in the effectiveness. This study provides a feasible method for the fast, accurate, and detailed extraction of the effective refuge areas of emergency shelters and also provides a reference for emergency planning for disaster prevention and mitigation.
A Day at the Bog: Preliminary Interpretation of Prehistoric Human Occupation at Ancient Lake Duvensee (Germany) by GPR Structures
Authors: Corradini Erica , Dreibrodt Stefan , Lübke Harald , Schmölcke Ulrich , Wieckowska-Lüth Magdalena , Wunderlich Tina , Wilken Dennis , Brozio Jan Piet , Rabbel Wolfgang
Published: July 2023

Understanding the landscape evolution and human-environmental interaction within it is one of the key tasks of early Holocene research. As mobile hunter–gatherers leave few traces of structural organization, understanding their habitats is relevant for comprehending these people. Rarely does the spatial distribution of artifacts correspond to the real pattern of past human activity, but rather shows the pattern of identified artifacts. Geophysical investigations try to fill this gap and have been applied increasingly in archaeological prospection delivering landscape reconstruction, which are verified and fine-tuned using corings and excavations. Despite promising 3D models, a tool to predict the location of undiscovered former human presence and the conditions which influenced people to move across the landscape is not well developed. The primary goal of this paper is to present a methodology for connecting spatial patterns of past human activity based on archaeological and geophysical data. We discuss different GPR (ground-penetrating radar) facies classified at the shoreline of the former Lake Duvensee and geomorphological variables, which leads to the possibility of understanding where and why people chose preferred areas to settle on former islands. We also demonstrate that Mesolithic hunter–gatherer groups preferred dry areas with access to open water for short-term campsites and flatter and more protected areas for specialized and repeatedly occupied campsites. The cardinal orientation of a campsite seems to be secondary to the local peat over-growing process and access to water.
Application of a Randomized Algorithm for Extracting a Shallow Low-Rank Structure in Low-Frequency Reverberation
Authors: Pang Jie , Gao Bo
Published: July 2023

The detection performance of active sonar is often hindered by the presence of seabed reverberation in shallow water. Separating the reverberations from the target echo and noise in the received signal is a crucial challenge in the field of underwater acoustic signal processing. To address this issue, an improved Go-SOR decomposition method is proposed based on the subspace-orbit-randomized singular value decomposition (SOR-SVD). This method successfully extracts the low-rank structure with a certain striation pattern. The results demonstrate that the proposed algorithm outperforms both the original Go algorithm and the current state-of-the-art (SOTA) algorithm in terms of the definition index of the low-rank structure and computational efficiency. Based on the monostatic reverberation theory of the normal mode, it is established that the low-rank structure is consistent with the low-frequency reverberation interference striation. This study examines the interference characteristics of the low-rank structure in the experimental sea area and suggests that the interferences of the fifth and seventh modes mainly control the low-rank structure. The findings of this study can be applied to seafloor exploration, reverberation waveguide invariant (RWI) extraction, and data-driven reverberation suppression methods.
GAN-Based Inversion of Crosshole GPR Data to Characterize Subsurface Structures
Authors: Zhang Donghao , Wang Zhengzheng , Qin Hui , Geng Tiesuo , Pan Shengshan
Published: July 2023

The crosshole ground-penetrating radar (GPR) technique is widely used to characterize subsurface structures, yet the interpretation of crosshole GPR data involves solving non-linear and ill-posed inverse problems. In this work, we developed a generative adversarial network (GAN)-based inversion framework to translate crosshole GPR images to their corresponding 2D defect reconstruction images automatically. This approach uses fully connected layers to extract global features from crosshole GPR images and employs a series of cascaded U-Net structures to produce high-resolution defect reconstruction results. The feasibility of the proposed framework was demonstrated on a synthetic crosshole GPR dataset created with the finite-difference time-domain (FDTD) method and real-world data from a field experiment. Our inversion network obtained recognition accuracy of 91.36%, structural similarity index measure (SSIM) of 0.93, and RAscore of 91.77 on the test dataset. Furthermore, comparisons with ray-based tomography and full-waveform inversion (FWI) suggest that the proposed method provides a good balance between inversion accuracy and efficiency and has the best generalization when inverting actual measured crosshole GPR data.
Research on Dynamic Deformation Laws of Super High-Rise Buildings and Visualization Based on GB-RAR and LiDAR Technology
Authors: Zhang Guojian , Wang Zhiyang , Sang Wengang , Zhou Baoxing , Wang Zhiwei , Yao Guobiao , Bi Jingxue
Published: July 2023

It is well-known that structures composed of super high-rise buildings accumulate damages gradually due to ultra-long loads, material aging, and component defects. Thus, the bearing capacity of the structures can be significantly decreased. In addition, these effects may cause inestimable life and property losses upon strong winds, earthquakes, and other heavy loads. Hence, it is necessary to develop real-time health monitoring methods for super high-rise buildings to deeply understand the running state during operation, timely discover potential safety potentials, and to provide reference data for reinforcement design. Along these lines, in this work, the built super high-rise buildings (Yunding Building) and super high-rise buildings (the Main Tower of the Shandong International Financial Center), under construction, were selected as the research objects. The overall dynamic deformation laws of super high-rise buildings were monitored by using ground-based real aperture radar (GB-RAR) technology for its advantages in non-contact measurement, remote monitoring, and real-time display of observation results. Denoising of the observation data was also carried out based on wavelet analysis. The visualization of the space state of the Yunding Building was realized based on handheld LiDAR technology. From the acquired results, it was demonstrated that the measuring accuracy of GB-RAR could reach the submillimeter level, while the noises under a natural state of wavelet analysis were eliminated well. The maximum deformation values of the Yunding Building and the Main Tower of Shandong International Financial Center under their natural state were 9.63 mm and 16.46 mm, respectively. Under sudden wind loads, the maximum deformation of the Yunding Building could be as high as 895.79 mm. The overall motion state switched between an S-shaped pattern, hyperbolic-type, and oblique line, presented the characteristics of nonlinear elastic deformation.
Spectral Calibration for SO2 Cameras with Light Dilution Effect Correction
Authors: Wu Kuijun , Guo Jianjun , Zhang Zihao , Zhang Huiliang , Li Juan , Li Faquan , He Weiwei
Published: July 2023

The detection ability of SO2 cameras has been improved effectively, while the calibration is still the main factor that limits their measurement accuracy. This paper presents a nonlinear calibration theory by considering the effect of light dilution due to the path radiance as well as the dependence of plume aerosol on scattering wavelength. This new spectral calibration method is used to retrieve the SO2 column density and emission rate of the Etna volcano. Results show that, compared with the DOAS calibration approach, the inversion error can be reduced by 13% if the new spectral calibration is adopted. The superiority of the proposed method will become more obvious for long-distance detection of optically thick plumes.
Enhancing Wheat Above-Ground Biomass Estimation Using UAV RGB Images and Machine Learning: Multi-Feature Combinations, Flight Height, and Algorithm Implications
Authors: Zhai Weiguang , Li Changchun , Cheng Qian , Mao Bohan , Li Zongpeng , Li Yafeng , Ding Fan , Qin Siqing , Fei Shuaipeng , Chen Zhen
Published: July 2023

Above-ground biomass (AGB) serves as an indicator of crop growth status, and acquiring timely AGB information is crucial for estimating crop yield and determining appropriate water and fertilizer inputs. Unmanned Aerial Vehicles (UAVs) equipped with RGB cameras offer an affordable and practical solution for efficiently obtaining crop AGB. However, traditional vegetation indices (VIs) alone are insufficient in capturing crop canopy structure, leading to poor estimation accuracy. Moreover, different flight heights and machine learning algorithms can impact estimation accuracy. Therefore, this study aims to enhance wheat AGB estimation accuracy by combining VIs, crop height, and texture features while investigating the influence of flight height and machine learning algorithms on estimation. During the heading and grain-filling stages of wheat, wheat AGB data and UAV RGB images were collected at flight heights of 30 m, 60 m, and 90 m. Machine learning algorithms, including Random Forest Regression (RFR), Gradient Boosting Regression Trees (GBRT), Ridge Regression (RR), Least Absolute Shrinkage and Selection Operator (Lasso) and Support Vector Regression (SVR), were utilized to construct wheat AGB estimation models. The research findings are as follows: (1) Estimation accuracy using VIs alone is relatively low, with R2 values ranging from 0.519 to 0.695. However, combining VIs with crop height and texture features improves estimation accuracy, with R2 values reaching 0.845 to 0.852. (2) Estimation accuracy gradually decreases with increasing flight height, resulting in R2 values of 0.519–0.852, 0.438–0.837, and 0.445–0.827 for flight heights of 30 m, 60 m, and 90 m, respectively. (3) The choice of machine learning algorithm significantly influences estimation accuracy, with RFR outperforming other machine learnings. In conclusion, UAV RGB images contain valuable crop canopy information, and effectively utilizing this information in conjunction with machine learning algorithms enables accurate wheat AGB estimation, providing a new approach for precision agriculture management using UAV remote sensing technology.