Triangle Structure Research Articles

Development and Optimization of Micro‐Nanotopographical Platforms for Surface Enhanced Raman Scattering Biomolecular Detection

AbstractTopologically designed micro‐ and nanostructured surface‐enhanced Raman scattering (SERS) substrates propel the advancements of innovative applications, including environmental and forensic point‐of‐care miniaturised devices via enhancing the localised electric fields for accurate analyte sensing. Herein, a method for designing, optimising and fabricating fine‐tuneable concentric hexagonal, triangular and rectangular SERS‐active micronano‐substrates is developed, with each unit yielding significant enhancement. Numerical simulations of the 3D near‐field electric field guided the optimal design process. While the coaxial SERS substrates consistently outperformed their solid counterparts, the hexagonal micro‐nano topologies exhibited ×21 higher signal than coaxial square arrays and a 12‐15‐fold increase over the triangle structures. Alternation of the topological designs from square to triangle lattice yielded more uniform plasmonic modes propagating along the 60°‐directions with various resonance modes playing key roles in light reflectance. This enables the engineering of platforms with tailor‐enhanced signals by changing the arrangement of micro‐nano patterned coaxial arrays. The fabricated SERS substrates are validated by detecting traumatic brain injury biomarkers, effectively yielding the characteristic fingerprint spectra of each neuro‐molecule. The straightforward development of sub‐micrometre tuneable SERS‐active architectures enables anelegant route for high‐throughput biochemical sensing, laying a platform for amplified bimolecular detection of disease biomarkers and integration in bioanalytical systems.

Patterns of rogue waves in the sharp-line Maxwell–Bloch system

The Maxwell–Bloch system describes light-matter interactions in a semi-infinitely long one dimensional two-level optical medium. Rogue wave patterns in the Maxwell–Bloch system under sharp-line limit are analytically studied. It is shown that when single internal parameter in bilinear expressions of rogue waves gets large, these waves would exhibit clear geometric patterns, which comprise fundamental (Peregrine) rogue waves arranged in shapes such as triangle, pentagon, heptagon and nonagon structures, with a possible lower-order rogue wave at the center. These rogue wave patterns are analytically determined from the root structure of the Yablonskii–Vorob’ev polynomial hierarchy through dilation, rotation, stretch and shear. It is also shown that when multiple internal parameters in the rogue wave solutions get large, new rogue wave patterns would arise, including heart-shaped structures, fan-shaped structures, and many others. Analytically, these patterns are determined by the root structure of the Adler–Moser polynomials through a linear transformation. Comparison between analytical predictions of these rogue patterns and true solutions shows excellent agreement.

Exploring the structure of household social capital in rural Vietnam: Applying Bayesian network approach.

This study aims to explore the structure of the households' social capital of rural Vietnam households with secondary data from 2008 to 2018. This paper applied the fundamental theories (resource and network theories) and the Bayesian network to estimate the interaction of proxies to explore the structure of social capital. Results showed that the triangle structure in household social capital with the core point is organization participation. The connections show the tendency from organization participation, linking to household networks. Alongside that, linking social capital and Organization participation are determinants of social capital indicators (social events, social cost). Therefore, this paper suggests employing proxies such as structured indicators for integrating social capital into the livelihood papers.

Dual arrowhead-shaped re-entrant auxetic hybrid metamaterial with adjustable thermal expansion

The lightweight metamaterial with the adjustable coefficient of thermal expansion (CTE) and Poisson's ratio (PR) has aroused great interest in potential engineering applications. However, the bifunctional metamaterials with dual negative properties exhibit relatively narrow ranges of CTE and PR, only considering one direction. In this work, a dual arrowhead-shaped re-entrant auxetic (DARA) hybrid metamaterial with controllable CTE is designed by combining a star-shaped re-entrant structure and a dual arrowhead inclined triangle structure. A theoretical model of the DARA unit cell is established to obtain CTE and PR solutions using the stiffness matrix method, which is verified by the finite element method (FEM). The theoretical model is used to further study the effect of geometric parameters, configuration, and base material on the thermal and mechanical properties. The DARA metamaterial can simultaneously realize the adjustable CTE and PR, especially a wide range of CTE under two directions, from negative to positive values. Furthermore, the 3D-printed DARA samples are fabricated to validate the CTE and PR values of the unit cell, which are in line with the FEM and theoretical values. The bi-metamaterial unit cell exhibits positive, quasi-zero, or negative CTE and PR owing to the synergistic effect of re-entrant and dual arrowhead structure. The deformation mechanism is proposed based on the structure's stretch-bending coupling and stretch-dominated design.

Biosynthesis of zinc oxide nanoparticles using water hyacinth extracts: Characterization, evaluation of antimicrobial and dye removal

In nanobiotechnology, synthesizing metal nanoparticles (NPs) using plant extracts has recently been increasing because of eco-friendly and low-cost methods. For this work, zinc oxide nanoparticles (ZnO NPs) have been synthesized by biosynthesis process using water hyacinth extracts (WHE). The water hyacinth (WH) was chosen because the WH is fast-growing and the most toxic aquatic plant in the world. Therefore, this work aims to apply these WHE to be a precursor in the biosynthesis of ZnO NPs (ZnOBio-NPs) based on the research of a sustainable environment. The ZnO NPs synthesized by the WHE were investigated for their antibacterial and photocatalytic activities. An UV-Vis spectrum showed a specific absorbance peak around 362 nm with an average band gap of 3.22 eV. As the result, TEM analysis revealed a triangle structure with an average size of about 64.05 nm. The peaks of XRD analysis show a hexagonal wurtzite structure. The ZnO NPs synthesized by the WHE showed higher antibacterial activity against S. aureus better than E. coli. It is interesting to note that the ZnOBio-NPs synthesized from the WHE can have an anti P. acnes (JB7) with a minimum inhibitory concentration (MIC) and a minimum bactericidal concentration (MBC) equal to 50 µg∙mL‒1 and 200 µg∙mL‒1, respectively. In addition, the ZnOBio-NPs also can effectively remove more than 90% of the malachite green within 180 minutes with extremely high reuse.

Insights into the writing process of the mask-free nanoprinting fluid force microscopy technology

Platelets are activated immediately when contacting with non-physiological surfaces. Minimization of surface-induced platelet activation is important not only for platelet storage but also for other blood-contacting devices and implants. Chemical surface modification tunes the response of cells to contacting surfaces, but it requires a long process involving many regulatory challenges to transfer into a marketable product. Biophysical modification overcomes these limitations by modifying only the surface topography of already approved materials. The available large and random structures on platelet storage bags do not cause a significant impact on platelets because of their smallest size (only 1–3 μm) compared to other cells. We have recently demonstrated the feasibility of the mask-free nanoprint fluid force microscope (FluidFM) technology for writing dot-grid and hexanol structures. Here, we demonstrated that the technique allows the fabrication of nanostructures of varying features including grid, circle, triangle, and Pacman-like structures. Characteristics of nanostructures including height, width, and cross-line were analyzed and compared using atomic force microscopy imaging. Based on the results, we identified several technical issues, such as the printing direction and shape of structures that directly altered nanofeatures during printing. Importantly, both geometry and interspace governed the degree of platelet adhesion, especially, the structures with triangular shapes and small interspaces prevent platelet adhesion better than others. We confirmed that FluidFM is a powerful technique to precisely fabricate a variety of desired nanostructures for the development of platelet/blood-contacting devices if technical issues during printing are well controlled.

Biomechanical analysis of a new cannulated screw for unstable femoral neck fractures.

The treatment of unstable femoral neck fractures (FNFs) remains a challenge. In this study, a new cannulated screw for unstable FNFs was designed to provide a new approach for the clinical treatment of these injuries, and its biomechanical stability was analyzed using finite element analysis and mechanical tests. An unstable FNF model was established. An internal fixation model with parallel inverted triangular cannulated screws (CSs) and a configuration with two superior cannulated screws and one inferior new cannulated screw (NCS) were used. The biomechanical properties of the two fixation methods were compared and analyzed by using finite element analysis and mechanical tests. The NCS model outperformed the CSs model in terms of strain and stress distribution in computer-simulated reconstruction of the inverted triangular cannulated screw fixation model for unstable FNFs. In the biomechanical test, the NCS group showed significantly smaller average femoral deformation (1.08 ± 0.15mm vs. 1.50 ± 0.37mm) and fracture line displacement (1.43 ± 0.30mm vs. 2.01 ± 0.47mm). In the NCS group, the mean stiffness was significantly higher than that in the CSs group (729.37 ± 82.20N/mm vs. 544.83 ± 116.07N/mm), and the mean compression distance was significantly lower than that in the CSs group (2.87 ± 0.30mm vs. 4.04 ± 1.09mm). The NCS combined with two ordinary cannulated screws in an inverted triangle structure to fix unstable FNFs can provide better biomechanical stability than CSs and exhibit a length- and angle-stable construct to prevent significant femoral neck shortening.

INDURG TRIAL Protocol: A Randomized Controlled Trial Using Indocyanine Green during Cholecystectomy in Acute Cholecystitis

Introduction: Laparoscopic cholecystectomy is one of the most common gastrointestinal surgeries, and bile duct injury is one of its main complications. The use of real-time indocyanine green fluorescence cholangiography allows the identification of extrahepatic biliary structures, facilitating the procedure and reducing the risk of bile duct lesions. A better visualization of the bile duct may help to reduce the need for conversion to open surgery, and may also shorten operating time. The main objective of this study was to determine whether the use of indocyanine green is associated with a reduction in operating time in emergency cholecystectomies. Secondary outcomes are the postoperative hospital stay, the correct intraoperative visualization of the Calot’s Triangle structures with the administration of indocyanine green, and the intraoperative complications, postoperative complications and morbidity according to the Clavien-Dindo classification. Methods: This is a randomized, prospective, controlled, multicenter trial with patients diagnosed with acute cholecystitis requiring emergency cholecystectomy. The control group will comprise 220 patients undergoing emergency laparoscopic cholecystectomy applying the standard technique. The intervention group will comprise 220 patients also undergoing emergency laparoscopic cholecystectomy for acute cholecystitis with prior administration of indocyanine green. Conclusion: Due to the lack of published studies on ICG in emergency laparoscopic cholecystectomy, this study may help to establish procedures for its use in the emergency setting.

Network community detection using higher-order structures

Summary In many real-world networks, it is often observed that subgraphs or higher-order structures of certain configurations, e.g., triangles and by-fans, are overly abundant compared to standard randomly generated networks (Milo et al., 2002). However, statistical models accounting for this phenomenon are limited, especially when community structure is of interest. This limitation is coupled with a lack of community detection methods that leverage subgraphs or higher-order structures. In this paper, we propose a new community detection method that effectively uses higher-order structures in a network. Furthermore, for the community detection accuracy, under an edge-dependent network model that consists of both community and triangle structures, we develop a finite-sample error bound characterized by the expected triangle degree, which leads to the consistency of the proposed method. To the best of our knowledge, this is the first statistical error bound and consistency result for community detection of a single network considering a network model with dependent edges. We also show, in both simulation studies and a real-world data example, that our method unveils network communities that are otherwise invisible to methods that ignore higher-order structures.

Dual Stabilization of a Tri-Metallofullerene Radical Er3@C80: Exohedral Derivatization and Endohedral Three-Center Bonding.

The enclosed space within fullerene molecules, capable of trapping metal clusters, offers an opportunity to investigate the behavior of metal atoms in a highly confined sub-nanometer environment. However, the studies on trimetallofullerenes M3@C80 have been very limited due to their difficult obtainability. In this paper, we present a new method for obtaining a tri-metallofullerene Er3@C80 through exohedral modification of the fullerene cage. Our findings reveal that Er3@C80 exhibits a radical character and can react with the dichlorobenzene radical to generate a stable derivative Er3@C80PhCl2. Theoretical calculations demonstrate the presence of a three-center two-electron metal-metal bond in the center of the fullerene cage. This bond serves to counterbalance the Coulomb repulsion between the Er ions. Consequently, both exohedral derivatization and endohedral three-center bonding contribute to the substantial stability of Er3@C80PhCl2. Furthermore, molecular dynamics simulations indicate that the Er3 cluster within the molecule possesses a rigid triangle structure. The availability of M3@C80 derivatives opens avenues for future investigations into interactions among metal atoms, such as magnetic coupling, within fullerene cages.

The Carbon Emission Reduction Effect and Spatio-Temporal Heterogeneity of the Science and Technology Finance Network: The Combined Perspective of Complex Network Analysis and Econometric Models

With the active promotion of the “carbon peaking and carbon neutrality” goals, science and technology finance (STF) is the important driving force of low-carbon development, and financial networks facilitate the aggregation and transformation of resources in space, so it is of great theoretical and practical significance to investigate the impact of science and technology finance networks (STFN) on carbon emissions (CE). Based on the 30 provinces of China from 2011 to 2019, this article used the STF development level in each province as the main indicator to construct the STFN. The complex network analysis and econometric models are combined, with the weighted degree values and betweenness centrality selected as typical network structure indicators incorporating into the econometric model to explore their impact on CE. Then, the Geographically and Temporally Weighted Regression (GTWR) model is applied to analyse the spatio-temporal heterogeneity of influencing factors. The results show the following: (1) From 2011 to 2019, the spatial structure of China’s STFN has changed significantly, and the status of the triangle structure consisting of Beijing–Tianjin–Hebei (BTH)–Yangtze River Delta (YRD)–Pearl River Delta (PRD) is gradually consolidated in the overall network, and the network structure tends to be stable. (2) The results of the benchmark regression show that the weighted degree value of the STFN has a significant inhibitory effect on CE, while betweenness centrality shows a certain positive effect on CE. (3) The weighted degree value has a more significant effect on CE reduction in the eastern region, while the betweenness centrality has a more significant effect on CE reduction in the central and western regions, but shows a significant promotion effect in the eastern region. (4) There is spatio-temporal heterogeneity in the effects of residents’ affluence, energy consumption, industrial structure, and environmental pollution on CE.

Musical timbre with varied amplitude envelope improves efficacy in auditory alarms

Current alarm standards used in safety critical environments (e.g., medical alarms used in hospitals) suffer from a myriad of complications with detectability, annoyance, and alarm fatigue affecting the wellbeing of patients and staff. To a large extent, these are based on the same simplistic, temporally invariant tones. Here we explore how insights from the acoustic properties of the musical triangle can aid in detection, reducing overall levels hence reducing annoyance ratings. Two tones are used, (1) a standard tone similar to those used in current medical devices, and (2) a tone synthesized based on the spectral-temporal structure of a concert triangle. We conducted a detection experiment where participants indicated if the auditory stimulus is heard when presented a range of signal-to-noise (SNR) ratios and a two-alternative force choice task to measure annoyance ratings. Although reductions in SNRs reduced detectability for the standard tone, similar deductions had no meaningful effect on detectability of tones modeled off the musical triangle. Crucially, we identified a number of triangle inspired tones which are both less annoying and more detectable than standard tones. This suggests that these more complex sounds can reduce annoyance without harming detection, offering useful insight to medical device sound design.

Arbitrary Triangle Structure Adaptive Mean PCA and Image Recognition

Arbitrary Triangle Structure Adaptive Mean PCA and Image Recognition

Anatomical features of the structure of the mandibular retromolar triangle as a target point for local anesthesia in dentistry and maxillofacial surgery

Anatomical features of the structure of the mandibular retromolar triangle as a target point for local anesthesia in dentistry and maxillofacial surgery

Study on the Static and Dynamic Performance of Concave Triangular Honeycomb Sandwich Panels

Negative Poisson's ratio (NPR) material perform well in shear resistance, impact resistance, and fracture resistance. In this study, a novel honeycomb sandwich panel is introduced, named Concave Triangular Honeycomb Sandwich Panel (CTHSP), which employs a concave triangle structure with NPR effect as the core layer. The study on the static and dynamic performance of CTHSPs are conducted through numerical simulation. Specifically, the influence of main geometric parameters (single cell size a, core layer thickness t, face-plate core layer thickness ratio h/H, concave angle α) on the bending stiffness, buckling critical load and natural frequency of CTHSPs are studied. Moreover, a new index of specific stiffness is introduced to evaluate the advantages of lightweight and high strength of the sandwich panels. The above research can provide a basis for the selection of CTHSPs in practical application.

Nonsequential double ionization channels control of CO2 molecules with counter-rotating two-color circularly polarized laser field by laser wavelength

Abstract Using the classical ensemble model, we investigate the effect of laser wavelength on the electron dynamics process of nonsequential double ionization (NSDI) for linear triatomic molecules driven by a counter-rotating two-color circularly polarized laser field. Based on the delay time between recollision and final double ionization, two particular ionization channels are separated: recollision-impact ionization (RII) and recollision-induced excitation with subsequent ionization (RESI). Numerical results show that with the increase of the laser wavelength, the triangle structure of the ion momentum distribution becomes more obvious, which indicates that the electron–electron correlation of NSDI is enhanced. In addition, we find that the ratio of the RESI channel gradually decreases with the increase of the laser wavelength, while the ratio of the RII channel is opposite. However, the dominant channel is still RESI. It means that the two ionization channels can be controlled effectively by changing the laser wavelength.

An additively manufactured model for preclinical testing of cervical devices.

Composite models have become commonplace for the assessment of fixation and stability of total joint replacements; however, there are no comparable models for the cervical spine to evaluate fixation. The goal of this study was to create the framework for a tunable non-homogeneous model of cervical vertebral body by identifying the relationships between strength, in-fill density, and lattice structure and creating a final architectural framework for specific strengths to be applied to the model. The range of material properties for cervical spine were identified from literature. Using additive manufacturing software, rectangular prints with three lattice structures, gyroid, triangle, zig-zag, and a range of in-fill densities were 3D-printed. The compressive and shear strengths for all combinations were calculated in the axial and coronal planes. Eleven unique vertebral regions were selected to represent the distribution of density. Each bone density was converted to strength and subsequently correlated to the lattice structure and in-fill density with the desired material properties. Finally, a complete cervical vertebra model was 3D-printed to ensure sufficient print quality. Materials testing identified a relationship between in-fill densities and strength for all lattice structures. The axial compressive strength of the gyroid specimens ranged from 1.5 MPa at 10% infill to 31.3 MPa at 100% infill and the triangle structure ranged from 2.7 MPa at 10% infill to 58.4 MPa at 100% infill. Based on these results, a cervical vertebra model was created utilizing cervical cancellous strength values and the corresponding in-fill density and lattice structure combination. This model was then printed with 11 different in-fill densities ranging from 33% gyroid to 84% triangle to ensure successful integration of the non-homogeneous in-fill densities and lattice structures. The findings from this study introduced a framework for using additive manufacturing to create a tunable, customizable biomimetic model of a cervical vertebra.

Impact of mechanical stratigraphy on deformation style and distribution of seismicity in the central External Dinarides: a 2D forward kinematic modelling study

The External Dinarides fold-thrust belt formed during Mid-Eocene–Oligocene times by SW-propagating thrusting from the Internal Dinarides towards the Adriatic foreland. Although previously considered as structurally quite uniform, recent work reported along-strike contrasting deformation styles in two structural domains within this fold-thrust belt. The two areas with very contrasting deformation styles are separated by the N–S-striking dextral Split-Karlovac Fault, a 250 km long, transpressive transfer fault. The southeastern domain is characterized by a thin-skinned SW-vergent nappe stack in contrast to the northwestern domain, where a set of blind, thick-skinned top-SW thrust duplexes prevail underneath the passive NE-vergent backthrusts. To better understand why the External Dinarides underwent such contrasting along-strike deformation, we reconsidered a temporal and spatial along- and across-strike distribution of Paleo-Mesozoic lithofacies to both sides of the Split-Karlovac Fault and estimated the role of mechanical stratigraphy on deformation styles in this part of the fold-thrust belt. Therefore, we constructed a new 2D kinematic forward model in the western backthrust-dominated domain. Our best-fit forward-modelled balanced cross section across the central Velebit Mtn. portrays a 75 km wide triangle zone. This zone took up at least 47 km of shortening during Eo-Oligocene times. It comprises a set of thin-skinned NE-vergent backthrusts detached in the upper Paleozoic atop a SW-vergent thick-skinned antiformal stack detached in the lower Paleozoic Adriatic basement. The NE-vergent backthrusts likely nucleated at lateral facies boundaries related to extensional half grabens that locally formed during Middle Triassic and Late Jurassic passive margin extension. During the Eo-Oligocene folding and thrusting, the selective inversion of inherited Mesozoic half grabens boundary faults into the NE-vergent backthrusts in the northwestern domain led to the observed along-strike changes in the deformation style of the External Dinarides. A seismotectonic analysis of instrumentally recorded earthquakes suggests contrasting seismic behaviour along the central and southern Velebit transects within the northwestern structural domain. The central Velebit Mtn. triangle structure appears to currently accommodate dominantly strike-slip motion, with reverse faulting being confined to east of the Split-Karlovac Fault. In contrast, seismicity along the southern Velebit cross section appears to be confined to the structurally lowermost parts of the triangle zone and the foreland, while it´s structurally higher parts are less seismically active. Also, a predominance of reverse faulting along this transect suggests ongoing accommodation of shortening in this part. Our results indicate that both the variations in the mechanical stratigraphy and the pre-orogenic structural inheritance obtained during rifting and passive margin stages exert control on contractional structures within the External Dinarides, including the distribution of present-day seismicity.

Bio-inspired design of a fence-type triangular flow channel for ammonia-hydrogen fuel cells

Appropriate channel design can improve the volume utilization and power density of proton exchange membrane fuel cells with ammonia decomposition gas as fuel (Ammonia-Hydrogen fuel cell, AHFC), and accelerate its application in commercial field. Aiming at the problem of low volumetric power density of AHFC, a triangular flow channel in the shape of a fence is designed based on the general rules of plant growth and simple structure of triangle. The influence of the cross-section size and length of triangular flow channel on gas-water-heat distribution of AHFC is analyzed by using a three-dimensional two-phase numerical model. The results show that the triangular flow channel improves the volume utilization and increases the volumetric power density greatly, and the increase amplitude is related to the load output. With the increase of the load output, the reactive gas gradually appeared starvation phenomenon, the longer the flow channel is, the more obvious starvation phenomenon is, which is opposite to the change trend of the water content in the membrane, and the hot spot value increases significantly. In addition, the maximum volumetric power density of a stack which includes 20-layer triangular channel fuel cells increased by 45% compared to the conventional square channel.

Colorimetric analysis of sulfate-reducing bacterial DNA based on catalytic hemin/G-quadruplex loaded rigid DNA triangle

Here a colorimetric sensing platform for sulfate-reducing bacterial DNA analysis was described by using a catalytic hemin/G-quadruplex loaded rigid DNA triangle assembly. This two-dimensional rigid DNA triangle structure was assembled by target bacterial DNA and three hairpin beacon probes. As three tips of hairpin probes carry specific recognition sites for G-quadruplex formation, target bacterial DNA trigger the opening of hairpin probes, not only forming a steady rigid DNA triangle but also activating the hemin/G-quadruplex horseradish peroxidase mimicking DNAzyme. The resultant hemin/G-quadruplex loaded rigid DNA triangle assembly catalyzes a colorimetric reaction with the signal intensity correlated to target concentrations, achieving target bacterial DNA detection with a detection limit as low as 23.99 fM. We further analyzed actual bacteria with this system, by acquiring bacterial DNA including bacteria-specific sequences with polymerase chain reaction (PCR), with the detection limit down to 1 cfu/mL. The system shows good selectivity for the target and resistance to interference, highly stable performance for serum samples application, showing great potential for application in the fields of genetic analysis, environmental monitoring, and medical testing.