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12 pages, 4279 KiB

Open AccessCommunication

Colorimetric Detection of Platinum (IV) Using 4-MethylSulfonylaniline-Modified Gold Nanoparticles in Lanthanum Carbonate API

by Zhongqiu Li, Longwei Li, Xiaotian Yang, Mengtao Duan, Zhiwei Li and Shiguo Sun

Sensors 2025, 25(11), 3274; https://doi.org/10.3390/s25113274 - 23 May 2025

Viewed by 491

Abstract

The control of elemental impurities is a critical step in the preparation of lanthanum carbonate, with platinum being one such impurity. Residual platinum is typically non-therapeutic and must be strictly controlled to ensure both safety and product quality. This paper describes a colorimetric [...] Read more.

The control of elemental impurities is a critical step in the preparation of lanthanum carbonate, with platinum being one such impurity. Residual platinum is typically non-therapeutic and must be strictly controlled to ensure both safety and product quality. This paper describes a colorimetric method for determining platinum (IV) in solutions based on the anti-aggregation of gold nanoparticles modified with 4-methylsulfonylaniline (4-MESA). The presence of Britton–Robinson buffer induces the aggregation of the 4-MESA-AuNPs nanoparticle probe. However, when platinum (IV) is introduced, it disrupts the aggregation of the 4-MESA-AuNPs, causing a color change in the solution. The absorbance at 524 nm showed a strong linear correlation in the concentration range of 1.00 × 10⁻² μM to 5.00 × 10² μM. Under optimal conditions, LOD and LOQ values of 10.00 × 10⁻³ μM and 3.03 × 10⁻² μM, respectively, were observed. This method has been successfully applied to the determination of platinum (IV) in lanthanum carbonate API. Full article

(This article belongs to the Special Issue Fluorescent and Colorimetric Sensors for Diagnostics and Drug Analysis)

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18 pages, 4367 KiB

Open AccessArticle

A Study on the Response Characteristics of Carbon Flux Exchange in Chinese Fir Forests to Vapor Pressure Deficit

by Zhenxiang Liu, Yongqian Wang, Luming Sun, Jing Jiang, Lan Jiang, Mengtao Wang, Jingjing Ye and Zhiqing Cheng

Sustainability 2024, 16(24), 10906; https://doi.org/10.3390/su162410906 - 12 Dec 2024

Cited by 1 | Viewed by 1040

Abstract

Forest carbon exchange is affected by various environmental variables, among which photosynthetically active radiation, temperature, saturated water vapor pressure deficit, and soil moisture content dominate. The global atmospheric temperature has risen significantly in recent decades, and the saturated water vapor pressure deficit has [...] Read more.

Forest carbon exchange is affected by various environmental variables, among which photosynthetically active radiation, temperature, saturated water vapor pressure deficit, and soil moisture content dominate. The global atmospheric temperature has risen significantly in recent decades, and the saturated water vapor pressure deficit has also increased, which has had a widespread and lasting impact on terrestrial carbon sinks. Here, using flux data from Mazongling in Jinzhai County from July 2020 to June 2023, the relationship between saturated water vapor pressure deficit and forest carbon flux was investigated on the basis of carbon flux changes in the forest ecosystem in response to environmental factors. Results revealed that vapor pressure deficit (VPD) and net ecosystem productivity (NEP) exhibited a quadratic relationship at the daily and monthly scales. When the VPD was greater than 1.2 kPa at the monthly scale, the NEP of the fir forest ecosystem decreased with increasing VPD. At the daily scale, the impact of the VPD on NEP was studied by month and season. The results revealed that the threshold value at which the VPD affected NEP differed across different months and seasons. Therefore, the VPD is an important factor in forest ecosystems and should be considered in the assessment of ecosystem carbon sinks. It also has far-reaching significance in the carbon cycle and ecological sustainable development. Full article

(This article belongs to the Section Air, Climate Change and Sustainability)

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18 pages, 66694 KiB

Open AccessReview

Emerging Characteristics and Properties of Moiré Materials

by Shaofeng Wang, Jizhe Song, Mengtao Sun and Shuo Cao

Nanomaterials 2023, 13(21), 2881; https://doi.org/10.3390/nano13212881 - 30 Oct 2023

Cited by 3 | Viewed by 3133

Abstract

In recent years, scientists have conducted extensive research on Moiré materials and have discovered some compelling properties. The Moiré superlattice allows superconductivity through flat-band and strong correlation effects. The presence of flat bands causes the Moiré material to exhibit topological properties as well. [...] Read more.

In recent years, scientists have conducted extensive research on Moiré materials and have discovered some compelling properties. The Moiré superlattice allows superconductivity through flat-band and strong correlation effects. The presence of flat bands causes the Moiré material to exhibit topological properties as well. Modulating electronic interactions with magnetic fields in Moiré materials enables the fractional quantum Hall effect. In addition, Moiré materials have ferromagnetic and antiferromagnetic properties. By tuning the interlayer coupling and spin interactions of the Moiré superlattice, different magnetic properties can be achieved. Finally, this review also discusses the applications of Moiré materials in the fields of photocurrent, superconductivity, and thermoelectricity. Overall, Moiré superlattices provide a new dimension in the development of two-dimensional materials. Full article

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12 pages, 4803 KiB

Open AccessCommunication

Spectral Physics of Stable Cu(III) Produced by Oxidative Addition of an Alkyl Halide

by En Cao and Mengtao Sun

Int. J. Mol. Sci. 2023, 24(21), 15694; https://doi.org/10.3390/ijms242115694 - 28 Oct 2023

Viewed by 1637

Abstract

In this paper, we theoretically investigated spectral physics on Cu(III) complexes formed by the oxidative addition of α-haloacetonitrile to ionic and neutral Cu(I) complexes, stimulated by recent experimental reports. Firstly, the electronic structures of reactants of α-haloacetonitrile and neutral Cu(I) and two kinds [...] Read more.

In this paper, we theoretically investigated spectral physics on Cu(III) complexes formed by the oxidative addition of α-haloacetonitrile to ionic and neutral Cu(I) complexes, stimulated by recent experimental reports. Firstly, the electronic structures of reactants of α-haloacetonitrile and neutral Cu(I) and two kinds of products of Cu(III) complexes are visualized with the density of state (DOS) and orbital energy levels of HOMO and LUMO. The visually manifested static and dynamic polarizability as well as the first hyperpolarizability are employed to reveal the vibrational modes of the normal and resonance Raman spectra of two Cu(III) complexes. The nuclear magnetic resonance (NMR) spectra are not only used to identify the reactants and products but also to distinguish between two Cu(III) complexes. The charge difference density (CDD) reveals intramolecular charge transfer in electronic transitions in optical absorption spectra. The CDDs in fluorescence visually reveal electron–hole recombination. Our results promote a deeper understanding of the physical mechanism of stable Cu(III) produced by the oxidative addition of an alkyl halide. Full article

(This article belongs to the Special Issue Chemical Bond and Bonding: Fundamental Aspects and Recent Developments)

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20 pages, 13285 KiB

Open AccessArticle

Calculation Method for Uplift Capacity of Suction Caisson in Sand Considering Different Drainage Conditions

by Chenggen Xu, Haitao Jiang, Mengtao Xu, Decheng Sun and Shengjie Rui

Sustainability 2023, 15(1), 454; https://doi.org/10.3390/su15010454 - 27 Dec 2022

Cited by 17 | Viewed by 3499

Abstract

Uplift capacity of suction caissons is one of the main concerns in the design of jackets with multi-caissons supported offshore wind turbine. The uplift movement of suction caissons leads to soil stress variation and increases the difficulty to predict the uplift capacity. In [...] Read more.

Uplift capacity of suction caissons is one of the main concerns in the design of jackets with multi-caissons supported offshore wind turbine. The uplift movement of suction caissons leads to soil stress variation and increases the difficulty to predict the uplift capacity. In this paper, a calculation method considering soil stress release and differential pressure contribution is proposed to predict the uplift capacity of caisson. Firstly, a series of numerical simulations based on the SANISAND model are conducted to study the uplift responses of suction caisson in sand, and it is verified with centrifuge test results. Considering the soil drainage condition during caisson being pulled out, the fully drained, partially drained and undrained are divided, and an equation is provided to assess differential pressure beneath the caisson lid incorporating the effects of main factors. Based on the above simulation results, a calculation method is proposed to calculate the uplift capacity of caissons. The prediction results are compared with the centrifuge model tests and previous studies, which indicate that the prediction accuracy is much improved. This proposed method contributes to the more accurate assessment of uplift capacity of suction caisson in sand. Full article

(This article belongs to the Special Issue Marine Geotechnical Engineering and Marine Civil Engineering Construction)

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24 pages, 6766 KiB

Open AccessReview

Application of SERS in the Detection of Fungi, Bacteria and Viruses

by Jiarui Xia, Wenwen Li, Mengtao Sun and Huiting Wang

Nanomaterials 2022, 12(20), 3572; https://doi.org/10.3390/nano12203572 - 12 Oct 2022

Cited by 57 | Viewed by 5324

Abstract

In this review, we report the recent advances of SERS in fungi, bacteria, and viruses. Firstly, we briefly introduce the advantage of SERS over fluorescence on virus identification and detection. Secondly, we review the feasibility analysis of Raman/SERS spectrum analysis, identification, and fungal [...] Read more.

In this review, we report the recent advances of SERS in fungi, bacteria, and viruses. Firstly, we briefly introduce the advantage of SERS over fluorescence on virus identification and detection. Secondly, we review the feasibility analysis of Raman/SERS spectrum analysis, identification, and fungal detection on SERS substrates of various nanostructures with a signal amplification mechanism. Thirdly, we focus on SERS spectra for nucleic acid, pathogens for the detection of viruses and bacteria, and furthermore introduce SERS-based microdevices, including SERS-based microfluidic devices, and three-dimensional nanostructured plasmonic substrates. Full article

(This article belongs to the Section Biology and Medicines)

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19 pages, 5740 KiB

Open AccessFeature PaperReview

Nonlinear Optical Microscopy and Plasmon Enhancement

by Yi Cao, Jing Li, Mengtao Sun, Haiyan Liu and Lixin Xia

Nanomaterials 2022, 12(8), 1273; https://doi.org/10.3390/nano12081273 - 8 Apr 2022

Cited by 10 | Viewed by 3192

Abstract

Improving nonlinear optics efficiency is currently one of the hotspots in modern optical research. Moreover, with the maturity of nonlinear optical microscope systems, more and more biology, materials, medicine, and other related disciplines have higher imaging resolution and detection accuracy requirements for nonlinear [...] Read more.

Improving nonlinear optics efficiency is currently one of the hotspots in modern optical research. Moreover, with the maturity of nonlinear optical microscope systems, more and more biology, materials, medicine, and other related disciplines have higher imaging resolution and detection accuracy requirements for nonlinear optical microscope systems. Surface plasmons of metal nanoparticle structures could confine strong localized electromagnetic fields in their vicinity to generate a new electromagnetic mode, which has been widely used in surface-enhanced Raman scattering, surface-enhanced fluorescence, and photocatalysis. In this review, we summarize the mechanism of nonlinear optical effects and surface plasmons and also review some recent work on plasmon-enhanced nonlinear optical effects. In addition, we present some latest applications of nonlinear optical microscopy system research. Full article

(This article belongs to the Special Issue Plasmon Assisted Near-Field Manipulation and Photocatalysis)

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16 pages, 1662 KiB

Open AccessArticle

Learning the Morphological and Syntactic Grammars for Named Entity Recognition

by Mengtao Sun, Qiang Yang, Hao Wang, Mark Pasquine and Ibrahim A. Hameed

Information 2022, 13(2), 49; https://doi.org/10.3390/info13020049 - 20 Jan 2022

Cited by 7 | Viewed by 3368

Abstract

In some languages, Named Entity Recognition (NER) is severely hindered by complex linguistic structures, such as inflection, that will confuse the data-driven models when perceiving the word’s actual meaning. This work tries to alleviate these problems by introducing a novel neural network based [...] Read more.

In some languages, Named Entity Recognition (NER) is severely hindered by complex linguistic structures, such as inflection, that will confuse the data-driven models when perceiving the word’s actual meaning. This work tries to alleviate these problems by introducing a novel neural network based on morphological and syntactic grammars. The experiments were performed in four Nordic languages, which have many grammar rules. The model was named the NorG network (Nor: Nordic Languages, G: Grammar). In addition to learning from the text content, the NorG network also learns from the word writing form, the POS tag, and dependency. The proposed neural network consists of a bidirectional Long Short-Term Memory (Bi-LSTM) layer to capture word-level grammars, while a bidirectional Graph Attention (Bi-GAT) layer is used to capture sentence-level grammars. Experimental results from four languages show that the grammar-assisted network significantly improves the results against baselines. We also investigate how the NorG network works on each grammar component by some exploratory experiments. Full article

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15 pages, 5192 KiB

Open AccessArticle

Detecting Small Anatomical Structures in 3D Knee MRI Segmentation by Fully Convolutional Networks

by Mengtao Sun, Li Lu, Ibrahim A. Hameed, Carl Petter Skaar Kulseng and Kjell-Inge Gjesdal

Appl. Sci. 2022, 12(1), 283; https://doi.org/10.3390/app12010283 - 28 Dec 2021

Cited by 9 | Viewed by 2703

Abstract

Accurately identifying the pixels of small organs or lesions from magnetic resonance imaging (MRI) has a critical impact on clinical diagnosis. U-net is the most well-known and commonly used neural network for image segmentation. However, the small anatomical structures in medical images cannot [...] Read more.

Accurately identifying the pixels of small organs or lesions from magnetic resonance imaging (MRI) has a critical impact on clinical diagnosis. U-net is the most well-known and commonly used neural network for image segmentation. However, the small anatomical structures in medical images cannot be well recognised by U-net. This paper explores the performance of the U-net architectures in knee MRI segmentation to find a relative structure that can obtain high accuracies for both small and large anatomical structures. To maximise the utilities of U-net architecture, we apply three types of components, residual blocks, squeeze-and-excitation (SE) blocks, and dense blocks, to construct four variants of U-net, namely U-net variants. Among these variants, our experiments show that SE blocks can improve the segmentation accuracies of small labels. We adopt DeepLabv3plus architecture for 3D medical image segmentation by equipping SE blocks based on this discovery. The experimental results show that U-net with SE block achieves higher accuracy in parts of small anatomical structures. In contrast, DeepLabv3plus with SE block performs better on the average dice coefficient of small and large labels. Full article

(This article belongs to the Special Issue Computational Methods for Medical and Cyber Security)

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38 pages, 11628 KiB

Open AccessFeature PaperReview

Carbon Dots: Synthesis, Properties and Applications

by Lin Cui, Xin Ren, Mengtao Sun, Haiyan Liu and Lixin Xia

Nanomaterials 2021, 11(12), 3419; https://doi.org/10.3390/nano11123419 - 16 Dec 2021

Cited by 297 | Viewed by 32572

Abstract

Carbon dots (CDs) are known as the rising star of carbon-based nanomaterials and, by virtue of their unique structure and fascinating properties, they have attracted considerable interest in different fields such as biological sensing, drug delivery, photodynamic therapy, photocatalysis, and solar cells in [...] Read more.

Carbon dots (CDs) are known as the rising star of carbon-based nanomaterials and, by virtue of their unique structure and fascinating properties, they have attracted considerable interest in different fields such as biological sensing, drug delivery, photodynamic therapy, photocatalysis, and solar cells in recent years. Particularly, the outstanding electronic and optical properties of the CDs have attracted increasing attention in biomedical and photocatalytic applications owing to their low toxicity, biocompatibility, excellent photostability, tunable fluorescence, outstanding efficient up-converted photoluminescence behavior, and photo-induced electron transfer ability. This article reviews recent progress on the synthesis routes and optical properties of CDs as well as biomedical and photocatalytic applications. Furthermore, we discuss an outlook on future and potential development of the CDs based biosensor, biological dye, biological vehicle, and photocatalysts in this booming research field. Full article

(This article belongs to the Special Issue Two-Dimensional Semiconductor Nanomaterials and Nanodevices)

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18 pages, 2653 KiB

Open AccessArticle

Machine Translation in Low-Resource Languages by an Adversarial Neural Network

by Mengtao Sun, Hao Wang, Mark Pasquine and Ibrahim A. Hameed

Appl. Sci. 2021, 11(22), 10860; https://doi.org/10.3390/app112210860 - 17 Nov 2021

Cited by 8 | Viewed by 2952

Abstract

Existing Sequence-to-Sequence (Seq2Seq) Neural Machine Translation (NMT) shows strong capability with High-Resource Languages (HRLs). However, this approach poses serious challenges when processing Low-Resource Languages (LRLs), because the model expression is limited by the training scale of parallel sentence pairs. This study utilizes adversary [...] Read more.

Existing Sequence-to-Sequence (Seq2Seq) Neural Machine Translation (NMT) shows strong capability with High-Resource Languages (HRLs). However, this approach poses serious challenges when processing Low-Resource Languages (LRLs), because the model expression is limited by the training scale of parallel sentence pairs. This study utilizes adversary and transfer learning techniques to mitigate the lack of sentence pairs in LRL corpora. We propose a new Low resource, Adversarial, Cross-lingual (LAC) model for NMT. In terms of the adversary technique, LAC model consists of a generator and discriminator. The generator is a Seq2Seq model that produces the translations from source to target languages, while the discriminator measures the gap between machine and human translations. In addition, we introduce transfer learning on LAC model to help capture the features in rare resources because some languages share the same subject-verb-object grammatical structure. Rather than using the entire pretrained LAC model, we separately utilize the pretrained generator and discriminator. The pretrained discriminator exhibited better performance in all experiments. Experimental results demonstrate that the LAC model achieves higher Bilingual Evaluation Understudy (BLEU) scores and has good potential to augment LRL translations. Full article

(This article belongs to the Special Issue Computational Methods for Medical and Cyber Security)

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9 pages, 1977 KiB

Open AccessArticle

Structural Color Control of CoFeB-Coated Nanoporous Thin Films

by Xiaomin Zhu, Cuicui Zhao, Weiwei Zhang, Bo Zhang, Mengtao Sun, Xinhua Chen, Vladimir I. Belotelov and Yujun Song

Coatings 2021, 11(9), 1123; https://doi.org/10.3390/coatings11091123 - 16 Sep 2021

Cited by 7 | Viewed by 2979

Abstract

Unlike color dyes, structural colors only slightly fade during long-term usage. Here, structural colors were controllably achieved by constructing CoFeB photonic crystal layers on the surface of a nanoporous aluminum oxide (AAO) substrate by magnetron sputtering deposition. The resulting material showed a wide [...] Read more.

Unlike color dyes, structural colors only slightly fade during long-term usage. Here, structural colors were controllably achieved by constructing CoFeB photonic crystal layers on the surface of a nanoporous aluminum oxide (AAO) substrate by magnetron sputtering deposition. The resulting material showed a wide visible spectral response and achieved structural color control with a high resolution, high color purity, and saturation. The angle-dependent color changes of CoFeB@AAO films were further investigated by changing the incident light angle. The simulation results of the model are consistent with the experiments, which is significant in practical applications. This strategy may have great potential applications for solid structure color coatings, anti-counterfeiting and security, information storage, and electromagnetic sensors. Full article

(This article belongs to the Special Issue Advances in Nanostructured Thin Films and Coatings)

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29 pages, 12715 KiB

Open AccessReview

The Thermal, Electrical and Thermoelectric Properties of Graphene Nanomaterials

by Jingang Wang, Xijiao Mu and Mengtao Sun

Nanomaterials 2019, 9(2), 218; https://doi.org/10.3390/nano9020218 - 6 Feb 2019

Cited by 105 | Viewed by 10919

Abstract

Graphene, as a typical two-dimensional nanometer material, has shown its unique application potential in electrical characteristics, thermal properties, and thermoelectric properties by virtue of its novel electronic structure. The field of traditional material modification mainly changes or enhances certain properties of materials by [...] Read more.

Graphene, as a typical two-dimensional nanometer material, has shown its unique application potential in electrical characteristics, thermal properties, and thermoelectric properties by virtue of its novel electronic structure. The field of traditional material modification mainly changes or enhances certain properties of materials by mixing a variety of materials (to form a heterostructure) and doping. For graphene as well, this paper specifically discusses the use of traditional modification methods to improve graphene’s electrical and thermoelectrical properties. More deeply, since graphene is an atomic-level thin film material, its shape and edge conformation (zigzag boundary and armchair boundary) have a great impact on performance. Therefore, this paper reviews the graphene modification field in recent years. Through the change in the shape of graphene, the change in the boundary structure configuration, the doping of other atoms, and the formation of a heterostructure, the electrical, thermal, and thermoelectric properties of graphene change, resulting in broader applications in more fields. Through studies of graphene’s electrical, thermal, and thermoelectric properties in recent years, progress has been made not only in experimental testing, but also in theoretical calculation. These aspects of graphene are reviewed in this paper. Full article

(This article belongs to the Special Issue Electronic and Thermal Properties of Graphene)

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