Structural Characteristics Research Articles

Extraction, Purification, Structural Characterization, and Antitumor Effects of Water-Soluble Intracellular Polysaccharide (IPSW-1) from Phellinus igniarius Mycelia.

Phellinus igniarius is a commonly used Chinese medicine fungus, and its polysaccharide is a valuable bioactive with antioxidant, antiaging, antitumor activities, etc. However, their bioactivities are influenced by their structural and physicochemical properties. Hence, this research isolated and purified homogeneous water-soluble intracellular polysaccharide (IPSW-1) from P. igniarius mycelia. A coherent study of its structural characteristics, conformation, and antitumor mechanisms was evaluated. The results showed IPSW-1 has no triple helical conformation according to the Congo red test. Based on FT-IR, periodate oxidation, Smith degradation, methylation analysis, 1H and 13C NMR spectroscopy data, and IPSW-1 consisted of α-d-glucopyranose (Glcp). The backbone of IPSW-1 consisted primarily of repeating three (1 → 6)-linked α-d-Glcp and one (1 → 3,4)-linked α-d-Glcp, with one terminal α-d-Glcp as side chains of 3-O-connected to the main chain for every four residues. The IPSW-1 had an inhibitory influence on HepG2 cell proliferation and inhibited the migration and invasion ability by down-regulating the expression levels of MMP-7 and RhoA. Moreover, IPSW-1 could inhibit the lysis of autophagosomes to inhibit autophagy and regulate mitochondrial membrane potential and pro-apoptotic protein Bax, which causes the caspase cascade to promote apoptosis, thereby inhibiting the role of tumor cells. These findings show IPSW-1 holds potential as an innovative functional food.

Laser induced fluorescence spectroscopy of the transition of jet cooled 14NO3 and 15NO3 II: the dispersed fluorescence spectrum from the 3rd E level of the ν4 mode (approximately the 2ν4 (e'), l = 0, level).

14NO3 and 15NO3 isotopomers were generated in a supersonic free jet expansion, and laser induced fluorescence (LIF) of the electronic transition was observed. Dispersed LIF spectra from the vibronic level at ∼770 cm-1 above the vibrationless level have been measured for each isotopomer. One remarkable characteristic of the dispersed fluorescence (DF) spectrum is that the ν2 fundamental is clearly observed, even though the transition 201 is forbidden in the electronic transition. Another is that two sets of vibrational structure are observed in the DF spectrum: one of the two sets is the structure with the origin at the excitation energy, and the other is that with the origin at the ν2 fundamental. These observations suggest that the fluorescent level has contribution from the ν2 mode. In part I (M. Fukushima, J. Mol. Spectrosc., 2022, 387, 111646), it has been reported that the ν4 progressions are one of the typical characteristics of the vibrational structure of the DF spectrum from the vibrationless level; the progressions have intensity gradually decreasing with increasing ν4 quantum number (named the "regular" distribution), and have members forbidden for the Δl = 0 selection rule. The intensity distribution of the ν4 progression with the origin at the ν2 fundamental is similar to that from the vibrationless level, while that with the origin at the excitation energy is drastically different from that from the vibrationless level. The Jahn-Teller (J-T) and Renner-Teller (R-T) interactions in the B̃2E' state enable us to interpret the intensity distributions of the ν4 progressions, in which relatively weak interactions are enough to reproduce the observed distributions. The spectral intensity distribution analyses adopting the two vibronic couplings suggest that the fluorescent level at ∼770 cm-1 above the vibrationless level is the 3rd E eigenstate of the ν4 mode. The major component of the ν4 3rd E state is the |Λ = ±1; v4 = 2, l4 = 0〉 level of the B̃2E' state, which is a vibrationally and a vibronically E' level, and it is therefore concluded that the major components of the fluorescent level are both of the ν2 = 1 level and ν4 = 2 level .

Structural design and electronic performance at MOx/diamond (M = Hf, Zr, Ti, Al, Sc, Y) interfaces for MOS device applications

The ultra-wide bandgap semiconductor diamond represents a promising potential for advancement and innovation in the field of electronic device development. Utilizing first-principles calculations, a thorough investigation has been performed on the structural and electronic characteristics of MOx/diamond (MOx = HfO2, ZrO2, TiO2, Al2O3, Sc2O3, Y2O3) heterostructures. The concentration of charge transfer at the high-κ oxide/diamond interfaces leads to obvious interface polarity localization characteristics. The studied MOx/diamond heterojunctions feature insulating interfaces without any gap states. The MOx/diamond supercells exhibit the ability to effectively confine holes on the diamond surface owing to the large band offsets (>1 eV), showing typical electronic properties of “type II” staggered energy band configurations. These findings demonstrate that the high-κ oxide MOx/diamond can serve as highly promising diamond gate dielectrics, and provide theoretical insights into the interfacial engineering of diamond MOS devices.

Research on collaborative locking strategy for distributed locking system of space manipulator

In this paper, the dynamic interaction between the locking system and the space manipulator is analyzed, and a misalignment tolerance capability analysis method for the distributed locking system of the space manipulator is proposed. Based on the structure and layout characteristics of the locking mechanism, the collision dynamics analysis between the manipulator and the locking system during the locking process is carried out, and the factors for the locking failure caused by the escape of the locking frame on the passive end of the locking mechanism are obtained. Aiming at the factors of escape of the locking frame and improving the misalignment tolerance of the locking system, the locking action matching of the active end of the locking system is carried out, which lays a foundation for the design of a collaborative locking strategy. The collaborative locking strategy model of the locking system was established to match the locking speed of the hook in the locking stage. Using the proposed misalignment tolerance capability analysis method combined with simulation software to simulate the conventional locking strategy and the collaborative locking strategy. By comparing the simulation results, the large misalignment tolerance capability of the collaborative locking strategy is verified.

Realization of hydrogenation-induced superconductivity in two-dimensional Ti2N MXene.

Two-dimensional (2D) MXene superconductors have been currently attracting considerable interest due to their unique electronic properties and diverse applicability. Utilizing first-principles computational methods, we have designed two distinct configurations of hydrogenated 2D Ti2N MXene materials, namely Ti2NH2 and Ti2NH4, and have conducted an exhaustive analysis of their structural stability, electronic characteristics, and superconductivity. Hydrogenation endows monolayer Ti2N with inherent metallic characteristics, as evidenced by an elevated density of states (DOS) at the Fermi level (Ef). Notably, Ti2NH4 exhibits a superconducting critical temperature (Tc) of 15.8 K, which is predominantly ascribed to the electronic contributions stemming from the Ti 3d orbitals. Analysis of phonon dispersion underscores the pivotal role that diverse lattice vibrational modes play in electron-phonon coupling (EPC), particularly the significance of low-frequency vibrations for facilitating electron pairing and the emergence of superconductivity. Furthermore, strain engineering can effectively modulate the superconducting properties of Ti2NH4, with a 2% tensile strain enhancing the EPC strength (λ) to 0.857 and increasing Tc to 18.7 K. This research elucidates the superconducting mechanisms of hydrogenated Ti2N structures, offering valuable insights for the development of novel 2D superconducting materials.

Design and research of face gear central limited slip differential and analysis of its influence on vehicle performance

In this paper, a new design scheme of face gear central limited-slip differential (F-LSD) is proposed, which aims to unveil the technical veil of central limited-slip differential and fill the research blank of face gear application in the field of central limited-slip differential. Through the analysis of structural principle and motion characteristics, the dynamic equilibrium equation and locking coefficient model of F-LSD are established. The Simulink simulation model based on F-LSD dynamics and the torque distribution model of the whole transmission system are established. A 7-DOF vehicle dynamics model was established, and the performance of F-LSD vehicle in four conditions of acceleration, climbing, chassis twist sine wave and double line change was studied by using simulation software. At the same time, four groups of four-wheel drive vehicles with different central differential speeds were set as the control test group. The simulation results show that F-LSD system can effectively improve the vehicle's dynamic performance and extrication performance, and will not reduce the vehicle's handling stability, which provides a reference for the practical application of the face gear central limited slip differential.

Minimum area of primitive broad-leaved Korean pine forest community based on biomass

Based on the survey data of nine primitive broad-leaved Korean pine forest plots ranging from 1 to 10.4 ha in Heilongjiang Province, this study used the moving window method and GIS technology to analyze the variation characteristics of the spatial distribution pattern of forest biomass in each plot. We explored the minimum area that can reflect the structural and functional characteristics of the primitive broad-leaved Korean pine forest, and used computer simulation random sampling method to verify the accuracy of the minimum area. The results showed that: (1) Through the analysis of the spatial distribution raster map of biomass deviation in the plots at various scales of 10 − 100 m, there is a minimum area (0.64 ha) for the critical range of biomass density variation in the primitive broad-leaved Korean pine forest. This minimum area based on biomass density can indirectly reflect the comprehensive characteristics of productivity level per unit area, structure, function, and environmental quality of the primitive broad-leaved Korean pine forest community. (2) Using computer simulation random sampling, it was found that only by sampling in a specific plot larger than or equal to the minimum area can equivalent or similar results be achieved as random sampling within the plot, indicating that the minimum area determined by the moving window method is accurate. (3) The minimum area determined in this paper is an excellent indicator reflecting the complexity of community structure, which can be used for comparing changes in community structure and function before and after external disturbances, and has a good evaluation effect. This minimum area can also be used as a basis for scientific and reasonable setting of plot size in the investigation and monitoring work of broad-leaved Korean pine forests in this region, thereby achieving the goals of improving work efficiency and saving work costs.

Differences in anterior segment structure and pupillary diastolic characteristics of eyes with primary angle closure suspects under light and shade environments

Objective: To investigate the anatomical structure changes of the anterior segment and dynamic pupil changes in eyes with suspected primary angle-closure (PACS) under light and dark conditions, and their correlation with the occurrence of acute primary angle-closure (APAC). Methods: This cross-sectional study collected data from 37 PACS patients (66 eyes) who visited the ophthalmology clinic of the Second Affiliated Hospital of Harbin Medical University between September 2019 and March 2021. The patients included 12 males and 25 females, with an average age of (61.27±7.35) years. Of the 66 eyes, 58 had no history of APAC in the contralateral eye, while 8 had a history of APAC in the contralateral eye. Patients without a history of APAC in both eyes underwent the dark room prone provocative test (DRPPT), and the eyes were divided into three groups: DRPPT- (44 eyes), DRPPT+ (14 eyes), and APAC (8 eyes). The DRPPT+ and APAC groups were combined into the APAC+ group. All patients underwent ultrasound biomicroscopy (UBM) to measure the changes in various parameters under light and dark conditions, including anterior chamber angle 500 (ACA500Δ) and 1000 (ACA1000Δ), angle opening distance 500 (AOD500Δ) and 1000 (AOD1000Δ), and iris thickness 500 (IT500Δ) and 1000 (IT1000Δ). Anterior segment analysis was performed to capture the pupil changes under light and dark conditions, recording pupil diameter, maximum dilation speed (Vmax), maximum constriction speed (Vmin), and average speed (Vm). Results: There was no significant difference in the parameters between DRPPT+ group and APAC group (P>0.05). In the difference analysis, it was found that the Vm value of DRPPT- group [(0.17±0.07) mm/s] was higher than that of APAC+ group [(0.13±0.06)mm/s], and the difference was statistically significant (P<0.05). There was no significant difference in other parameters (P>0.05). Vmax was positively correlated with temporal ACA1000Δ and temporal AOD1000Δ in all patients with PACS (r=0.302, 0.260; P<0.05), Vmin was negatively correlated with temporal ACA1000Δ and temporal AOD1000Δ (r=-0.338, -0.330; P<0.05). Conclusions: The dynamic changes in the anterior segment and pupil under different lighting conditions provide insights into the risk factors and potential predictive indicators for the occurrence of APAC in PACS patients.

Self-assembled prussian blue nanoparticles on MXene quantum dots modified AuNPs for sensitive and reproducible biosensing of ovarian specific antigen (CA-125)

In this study, a practical approach has been developed to detect ovarian specific antigen (CA-125) with high sensitivity and specificity. The method utilizes enhanced differential pulse voltammogram signals of a self-assembled prussian blue nanoparticles (PB) decorated on MXene Quantum dots (QDs) supported by electrodeposited Au nanoparticles modified glassy carbon electrode (AuNP/PB/MXene QD/GCE). The fabrication procedure was completed by casting an optimized value of streptavidin and CA-125 antibody on the transducing platform. The improved electrochemical characteristics of the MXene QD/PB/AuNPs modification were ascribed to the combined impacts of MXene QD, PB, and AuNPs. The integration of MXene QD-PB composite within the modified layer contributed to enhanced mechanical strength. Additionally, the inclusion of gold nanoparticles (AuNPs) notably enhanced conductivity and promoted the attachment of anti-CA-125 onto the modified glassy carbon electrode (GCE), consequently improving sensitivity. Several analytical methods, such as energy-dispersive X-ray spectroscopy (EDS) and field emission scanning electron microscopy (FE-SEM) were utilized to investigate the structural, elemental composition and morphological characteristics. The functionality of the newly created immunosensor was evaluated using electrochemical impedance spectroscopy, differential pulse voltammetry and cyclic voltammetry to evaluate the synergistic effects. By employing this highly efficient analysis strategy, the measurement of CA-125 with differential pulse voltammetry (DPV) results a remarkable sensitivity with a detection limit of 0.57 pU.mL−1 and a wide linear range of 1 pU.mL−1 to 0.12 nU.mL−1 (R2 = 0.9824). Comparable results were obtained by analyzing serum samples from ovarian cancer patients at various stages. This study offers a significant insight into the advancement of immunosensor techniques for fabricating electrochemical transducers for the clinical detection of CA-125.

Simulated Gastrointestinal Digestion and Fecal Fermentation Characteristics of Exopolysaccharides Synthesized by Schleiferilactobacillus harbinensis Z171.

Exopolysaccharides (EPSs) produced by Lactobacillus have important physiological activities and are commonly used as novel prebiotics. A strain of Lactobacillus with high EPS yield was identified as Schleiferilactobacillus harbinensis (S. harbinensis Z171), which was isolated from Chinese sauerkraut. The objective of this study was to investigate the in vitro simulated digestion and fecal fermentation behavior of the purified exopolysaccharide fraction F-EPS1A from S. harbinensis Z171 and its influence on the human intestinal flora composition. The in vitro digestion results showed that the primary structural characteristics of F-EPS1A, such as morphology, molecular weight, and monosaccharide composition remained stable after saliva and gastrointestinal digestion. Compared with the blank group, the fermentation of F-SPS1A by fecal microbiota decreased the diversity of the bacterial communities, significantly promoted the relative abundance of Bifidobacterium and Faecalibacterium, and decreased the relative abundance of Lachnospiraceae_Clostridium, Fusobacterium, and Oscillospira. Reverse transcription polymerase chain reaction (RT-PCR) analysis also showed that the population of Bifidobacterium markedly increased. Furthermore, the total short-chain fatty acid levels increased significantly, especially for butyric acid. Gas chromatography-mass spectrometry (GC-MS) results showed that F-EPS1A could be fermented by the human gut microbiota to synthesize organic acids and derivative metabolites that are beneficial to gut health. Therefore, these findings suggest that F-EPS1A could be exploited as a potential prebiotic.

Structural Insights into the Substrate Recognition and Catalytic Mechanism of a GH16 βκ-Carrageenase from Wenyingzhuangia fucanilytica.

Understanding the substrate specificity of carrageenases has long been of interest in biotechnology applications. So far, the structural basis of the βκ-carrageenase that hydrolyzes furcellaran, a major hybrid carrageenan, remains unclear. Here, the crystal structure of Cgbk16A_Wf, as a representative of the βκ-carrageenase from GH16_13, was determined, and the structural characteristics of this subfamily were elucidated for the first time. The substrate binding mode was clarified through a structure analysis of the hexasaccharide-bound complex and molecular docking. The binding pocket involves a conserved catalytic motif and several specific residues associated with substrate recognition. Functions of residues R88, E290, and E184 were validated through site-directed mutagenesis. Comparing βκ-carrageenase with κ-carrageenase, we proposed that their different substrate specificities are partly due to the distinct conformations of subsite -1. This research offers a comprehensive understanding of the recognition mechanism of carrageenases and provides valuable theoretical support for enzyme modification and carrageenan oligosaccharide preparation.

Changes to Structural and Compositional Features of Water-Soluble Arabinoxylans in Sourdough Bread.

This research investigates the influence of milling methods and starter cultures on the structural characteristics of water-extractable arabinoxylans (WE-AX) in stone-milled whole-grain flour and sourdough bread. Stone milling was conducted to generate six different whole wheat flour samples, from which sourdough bread was produced using wheat and rye starter cultures. The study found that both milling parameters and the type of starter culture significantly impacted the fine structural details of WE-AX, including sugar composition, arabinoxylan (AX) content, and the arabinose-to-xylose (A/X) ratio values. These differences were statistically significant (p < 0.05). Furthermore, transforming flour into sourdough bread resulted in the molecular degradation of AX, significantly reducing its molecular weight and leading to a more heterogeneous fine structure. This detailed characterization of AX's alterations during food processing provides insights into evaluating its potential health benefits in whole-grain products.

Interpenetrated Donor-Acceptor Heterojunctions in 2D Conjugated Dibenzo[g,p]chrysene-Based Kagome Covalent Organic Frameworks.

Dibenzo[g,p]chrysene can be viewed as a constrained propeller-shaped tetraphenylethylene with reduced curvature and has been utilized to construct dual-pore kagome covalent organic frameworks (COFs) with tightly packed two-dimensional (2D) layers owing to its rigid and more planar structural characteristics. Here, we introduce 2D COFs based on the node 4,4',4″,4‴-(dibenzo[g,p]chrysene-2,7,10,15-tetraphenyl)tetraamine (DBCTPTA) featuring extended conjugation compared to the dibenzo[g,p]chrysene-3,6,11,14-tetraamine (DBCTA) node. We establish two exceptionally crystalline imine-linked 2D COFs with a hexagonal dual-pore kagome structure based on the DBCTPTA core. The newly synthesized thienothiophene (TT) and benzodithiophene (BDT)-based DBCTPTA COFs show a tight stacking behavior between adjacent layers. Furthermore, we obtained an unprecedented, interpenetrated electron-donor/acceptor host-guest system with an electron-donating BDT DBCTPTA COF synthesized in situ with the soluble fullerene derivative [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) serving as molecular acceptor. The BDT DBCTPTA COF@PCBM film shows a much shorter amplitude-averaged PL lifetime of 7 ± 2 ps compared to 30 ± 4 ps of the BDT DBCTPTA COF film, indicating the light-induced charge transfer process. The successful in situ formation of interpenetrated donor-acceptor heterojunctions within 2D COFs offers a promising strategy for establishing D-A heterojunctions in diverse framework materials with open channel systems.

TH-graphyne: a new porous bidimensional carbon allotrope.

Graphyne and two-dimensional porous carbon-based materials have garnered significant attention due to their interesting structural characteristics and essential properties for new technological applications. Within this scope, this work investigates the structural, thermal, electronic, optical, and mechanical properties of a novel two-dimensional allotrope that combines triangular (T) and hexagonal (H) rings, connected by acetylenic linkages (graphyne-like), thus named TH-graphyne (TH-GY). This study comprehensively characterizes the proposed system's behavior using density functional theory, ab initio molecular dynamics, and classical reactive molecular dynamics simulations. Our results confirm the structural stability of TH-GY. AIMD simulations demonstrate the material's thermal stability at elevated temperatures, while phonon dispersions indicate its dynamical stability. Electronic band structure calculations show that the system is metallic. The analysis of optical properties reveals intense activity in the visible and UV regions, with pronounced anisotropy. A machine learning interatomic potentials model was developed for TH-GY and used to determine the mechanical behavior of the system, which exhibits Young's modulus ranging from 263 to 356 GPa, highlighting its flexibility. Classical reactive MD simulations elucidate the fracture behavior of TH-GY, revealing distinct fracture patterns and mechanical anisotropy.

Water-resistant adhesive tackified by dynamic adhesion factor of nucleotide

Underwater adhesives have gained much attention across diverse fields including tissue adhesives, wearable electronics, and underwater electronics. However, it remains challenging to design a tough and stable underwater adhesion interface only relying on physical adhesion mechanisms, because the adhesion factors of the physical adhesives are limited and bound by molecular networks. Inspired by the toughening theory of “sacrificial bonds”, we present a strategy of dynamic adhesion factor to fabricate a tough and stable underwater adhesion interface. The adhesives tackified by nucleotide of dynamic adhesion factor are successfully developed and demonstrate excellent adhesion behavior in aquatic environments. The adhesion factor of nucleotide featuring reversible dynamic structural characteristics not only facilitates easier interaction with the substrate but also effectively dissipates failure stress and mitigates stress concentration when exposed to destructive stress. Moreover, the adhesives exhibit excellent recyclability, on-demand detachability, and long-term stability. Importantly, this strategy demonstrated a universality for variable monomers to construct tough underwater adhesion. It is anticipated that the dynamic adhesion factor strategy will inspire a new paradigm in the advancement of next-generation water-resistant adhesives.

Topological structural characteristics in patients with systemic lupus erythematosus with and without neuropsychiatric symptoms

PurposeThis study investigated the topological structural characteristics of systemic lupus erythematosus (SLE) with and without neuropsychiatric symptoms (NPSLE and non-NPSLE), and explore their clinical implications.MethodsWe prospectively recruited 50 patients with...

Electron beam induced graft polymerized anti oil-fouling biaxial polypropylene membrane with harsh environment tolerance

The intrinsic hydrophobic behavior of biaxial-oriented polypropylene microporous membrane limits its broad application area by leading serious membrane fouling. An environment-friendly, practical, and facile to large-scale prepared surface modification process is designed to enhance the membrane wettability and oil fouling. By employing electron beam radiation, acrylic acid, and polyvinyl alcohol in the pre-irradiation-induced graft polymerization process, a micro-nano structure was developed and the surface roughness was increased from 66.5 nm to 99.3 nm. Enhancing the grafting ratio further reduces the pore size of the final modified membrane from 54 nm to 25 nm, which is significantly smaller than the size of the emulsified oil droplet. By modifying the morphological and structural characteristics of the grafted membrane, excellent oil fouling resistance features are attained with UWOCA value 161° and separation efficiency of 99.3 %. Moreover, the theoretical explanations for hydrophilicity and oil-fouling resistance of modified membranes are also developed using DFT calculations and the Hermia model, which shows alignment with experimental data. Consequently, considerable improvements in wettability, thermal and mechanical behavior are obtained by this facial surface modification approach, which could further broaden the modified membrane's applications area in membrane separation technology while lengthening its service life.

Influence of vacuum and high-temperature on the evolution of mechanical strength and microstructure of alkali-activated lunar regolith simulant

Alkali-activated lunar regolith (AALR) has become one of the most promising lunar building materials, offering the potential to support the construction of large-scale lunar structures. This paper presents a comprehensive experimental investigation on the fresh properties, physical properties, mechanical performance and microstructural characteristics of alkali-activated lunar regolith simulant (AALRS) considering the effects of lunar environments (high-temperature, vacuum and coupled high-temperature and vacuum), alkaline activators (sodium hydroxide and sodium silicate) and curing age. The results show that AALRS under high-temperature environment exhibits higher strength while the strength development is limited. However, AALRS under vacuum environment exhibits lower strength but the strength increases as the curing time increases. In terms of pore structure, the volume fractions of macro voids for SH-V and SS-V account for up to 50.94 % and 63.64 %, respectively, which are 12.22 % and 7.95 % higher than those of SH-H and SS-H. Regarding the impact of coupled high-temperature and vacuum environment, the compressive strength of SH-HV-7 is reduced by 47.8 % compared to that of SH-H-7, while the compressive strength of SS-HV-7 exhibits a 57.2 % increase over that of SS-H-7. The sodium hydroxide-activated (SH-activated) system and sodium silicate-activated (SS-activated) system demonstrate fundamentally intrinsic differences in terms of reaction products, structure build-up and pore structure. The positive optimization mechanism and reverse degradation effect of vacuum environment on the performance of AALRS paste were revealed. Finally, the evolution of structural characteristics of AALRS paste under different environments was elucidated.

Optical and structural transformations in polyethylene terephthalate (PET) films subjected to Ag[formula omitted]-ion implantation and subsequent Au[formula omitted]-ion irradiation

We report on the dual effects of ion implantation and swift heavy ion on the optical and structural characteristics of polyethylene terephthalate (PET) films using UV–Vis spectrophotometry, FTIR and X-ray diffraction measurements. Samples were first implanted with 150 keV Ag+-ions at different fluences of 1 ×1016, 5 ×1016, and 1 ×1017 ions/cm2, and thereafter irradiated with 30 MeV Au7+-ions at different fluences, while analysing elemental depth profile in situ on the Time of Flight Heavy Ions Elastic Recoil Detection (ToF-Hi-ERDA) instrument. The elemental depth profile measurements showed considerable atomic depletion of hydrogen from 36% down to below 6% and oxygen from 18% to about 5%. The proportion of carbon increased from 45% to over 87%. The optical bandgap decreased with increasing ion implantation fluence and reduced even further on irradiation with 30 MeV 197Au7+-ions. The most notable outcome of the implantation was the onset of the precipitation of gold nanoparticles (Au-NPs) in the PET matrix, marked by Localised Surface Plasmon Resonance effects, coincided with a relatively significant drop in the bandgap energy. This latter effect could only be best explained as the result of these Au-NPs in the PET. This suggests that optical bandgap tuning in polymer films, usually achievable through high fluence implantation at low energy (i.e., keV), could also be realized through low fluence irradiation with MeV energy ions. It is surmised that, for the noble metals, NP-induced bandgap modification in PET precludes the need for high fluence to achieve the same. This has the obvious advantage of bandgap alterations at much lower structural damage to the target polymer. As reported by FTIR results, one can observe structural changes with the formation of new chemical bonds on thin films. X-ray diffraction results exhibited one prominent peak corresponding to the (100) plane, which varies in intensity with increased implantation fluence, suggesting a change in the crystallinity of the PET. The decrease in (100) peak or crystallinity was well connected with the presence and decrease of 847, 970, and 1471 cm−1 peaks, which were assigned to the ethylene glycol molecular groups.

G[formula omitted]BFNN: Generalized geodesic basis function neural network

Real-world data is typically distributed on low-dimensional manifolds embedded in high-dimensional Euclidean spaces. Accurately extracting spatial distribution features on general manifolds that reflect the intrinsic characteristics of data is crucial for effective feature representation. Therefore, we propose a generalized geodesic basis function neural network (G2BFNN) architecture. The generalized geodesic basis functions (G2BF) are defined based on generalized geodesic distances. The generalized geodesic distance metric (G2DM) is obtained by learning the manifold structure. To implement this architecture, a specific G2BFNN, named discriminative local preserving projection-based G2BFNN (DLPP-G2BFNN) is proposed. DLPP-G2BFNN mainly contains two modules, namely the manifold structure learning module (MSLM) and the network mapping module (NMM). In the MSLM module, a supervised adjacency graph matrix is constructed to constrain the learning of the manifold structure. This enables the learned features in the embedding subspace to maintain the manifold structure while enhancing the discriminability. The features and G2DM learned in the MSLM are fed into the NMM. Through the G2BF in the NMM, the spatial distribution features on manifold are obtained. Finally, the output of the network is obtained through the fully connected layer. Compared with the local response neural network based on Euclidean distance, the proposed network can reveal more essential spatial structure characteristics of the data. Meanwhile, the proposed G2BFNN is a generalized network architecture that can be combined with any manifold learning method, showcasing high scalability. The experimental results demonstrate that the proposed DLPP-G2BFNN outperforms existing methods by utilizing fewer kernels while achieving higher recognition performance.