Structural Analysis Research Articles

Alkaloids as Additional Weapons in the Fight against Breast Cancer: A Review.

Breast carcinoma is among the most frequent cancerous tumour in females around the globe. The major modalities now employed in the therapeutic management of breast cancer include surgeries, chemotherapy, and specialized medicines. Despite their potential to help individuals' problems, they are also associated with many negative impacts. As a result, natural products are increasingly regarded to be a preferable alternative. Alkaloids are essential biochemical substances that can be used to develop new drugs. Numerous alkaloids that originate from natural plants have been shown in vitro and in vivo to have anti-proliferation and anti-metastasis actions on different kinds of carcinoma. According to the data collected in this study, the utilization of alkaloids as anti-tumor medicines appears to be extremely potent; nevertheless, extensive studies and clinical trials are required before utilizing individual alkaloids. In this overview, we provide a detailed and vital exploration of pre-existing alkaloids possessing anti-tumor activities due to bioactive compounds. This study also includes an overview of synthesized analogues and pharmacological characteristics that will be beneficial to scientists working on alkaloids for medicinal purposes. In a recent survey of the literature, alkaloids are an important component of plantderived antitumor medicines that hold great potential for the future development of cancer therapy and preventive therapies. We have also discussed structural analysis relationship (SAR) studies. Moreover, it covers clinical trial medications and FDA-approved medicines from the last five years that will be useful in further research.

MagIC-Cryo-EM: Structural determination on magnetic beads for scarce macromolecules in heterogeneous samples.

Cryo-EM single-particle analyses typically require target macromolecule concentration at 0.05∼5.0 mg/ml, which is often difficult to achieve. Here, we devise Magnetic Isolation and Concentration (MagIC)-cryo-EM, a technique enabling direct structural analysis of targets captured on magnetic beads, thereby reducing the targets' concentration requirement to < 0.0005 mg/ml. Adapting MagIC-cryo-EM to a Chromatin Immunoprecipitation protocol, we characterized structural variations of the linker histone H1.8-associated nucleosomes that were isolated from interphase and metaphase chromosomes in Xenopus egg extract. Combining Du plicated S election T o E xclude R ubbish particles (DuSTER), a particle curation method that removes low signal-to-noise ratio particles, we also resolved the 3D cryo-EM structures of H1.8-bound nucleoplasmin NPM2 isolated from interphase chromosomes and revealed distinct open and closed structural variants. Our study demonstrates the utility of MagIC-cryo-EM for structural analysis of scarce macromolecules in heterogeneous samples and provides structural insights into the cell cycle-regulation of H1.8 association to nucleosomes.

Innovative device for crack monitoring and deflection analysis in structures: Improved accuracy, safety and efficiency

It is of the utmost importance to ensure the structural integrity of buildings in order to guarantee the safety of their occupants. Conventional techniques for monitoring cracks and conducting flexural analysis during loading and unloading tests frequently prove inadequate in terms of accuracy and safety. This study introduces ES1293890 U, an innovative dual-purpose device designed for the precise remote monitoring of cracks and comprehensive flexural analysis. The device is integrated seamlessly into structural health monitoring (SHM) and building information modelling (BIM) systems, thereby providing a holistic approach to structural assessment.The ES1293890 U device offers superior accuracy, with a resolution of 0.01 mm and a maximum deviation of 0.007 mm, which makes it a more effective alternative to existing commercial solutions. The utilisation of recycled and biodegradable materials has the effect of reducing production costs, thereby facilitating the undertaking of more frequent and economically viable testing and monitoring. This enhanced affordability is of paramount importance for the maintenance of building safety and structural integrity through regular assessments.A noteworthy attribute of the ES1293890 U is its capacity to conduct remote measurements, obviating the necessity for professionals to enter potentially hazardous test areas. This not only ensures the safety of personnel but also enables continuous and uninterrupted monitoring, with real-time data capture facilitating timely and informed decision-making.In comparison to traditional gauges, the ES1293890 U exhibits enhanced performance in the monitoring of slab deflections, attributable to its elevated accuracy and comprehensive data acquisition capabilities. This device represents a substantial advancement in structural assessment technology, providing a reliable and efficient tool for improving building safety and integrity. The ES1293890 U's innovative approach and cost-effective design have the potential to revolutionise structural monitoring practices, making it an invaluable asset to both the scientific community and the construction industry.

Elítur á Íslandi – einsleitni og innbyrðis tengsl

Á Íslandi hefur það gjarnan verið trú fólks að félagslegur og efnahagslegur jöfnuður einkenni þjóðina og að hvers konar elítur séu lítt áberandi. Engu að síður eru vísbendingar um að elítur séu til staðar, og ennfremur að þær séu styrkjast og ójöfnuður að aukast. Markmið greinarinnar er að greina viðskiptaog atvinnulífselítuna á Íslandi árin 2014 og 2015 út frá tengslum hennar við aðrar elítur sem og innbyrðis tengslum. Slík greining gefur vísbendingar um hversu opin elítan er, tengsl hennar við almenning, og um lýðræðislega uppbyggingu hópsins. Byggt er á tveimur gagnasöfnum; Vald og lýðræði – elíturannsókn og Kynjajafnrétti við stjórn atvinnulífsins: stefna, þróun og áhrif. Til að fá myndræna sýn á innbyrðis tengsl elítuflokka var notast við hugbúnaðarpakkann igraph fyrir R. Niðurstöðurnar sýna talsverð innbyrðis tengsl á milli einstaklinga sem mynda viðskipta- og atvinnulífselítuna. Einsleitni í búsetu, mælt í póstnúmerum er sterk, einkum meðal karla og þeirra sem eldri eru. Búsetueinsleitni þeirra sem eru í forystuhlutverki stjórnmálanna er fjórum sinnum meiri en þeirra sem ekki taka þátt í slíku starfi. Svipað mynstur sést þegar tengslin við íþróttahreyfinguna eru skoðuð; eftir því sem þátttaka einstaklings í íþróttastarfi er meiri, þeim mun meiri er búsetueinsleitnin. Niðurstöðurnar benda til þess að íslenska þjóðfélagið sé lagskipt og að tiltekin gjá sé á milli elítunnar og almennings. Það gefur til kynna að mikilvægt sé að huga að því hversu lýðræðisleg uppbygging hópsins er og hvort hætta sé á að einsleitni í ákvarðanatöku verði of mikil.

Implementation of a visualization teaching approach for mechanical analysis in civil engineering structures

AbstractThe visualization method for mechanics knowledge in civil engineering courses is very important, which can help students learn abstract mechanics. Combined with the structural analysis software, this paper develops a visualization teaching approach for mechanical analysis in civil engineering structures based on the proposed deformation decomposition method, such as elastic mechanics, material mechanics and structural dynamics. Compared with traditional strain analysis method, the proposed method is more intuitive and can identify more macroscopic basic deformations. By aid of a survey for undergraduate students and master students, the teaching effectiveness of the visualization course is higher than that of the blackboard writing course. Besides, Mann–Whitney test results show that there is a significant difference. The proportion of undergraduate students that think the combination of visualization has good effects are greater than those of master students. The proposed visualization teaching approach can be promoted in mechanics courses of civil engineering.

Efficient numerical simulation method for nonlinear guided wave in frequency domain

Abstract Nonlinear ultrasonic guided wave has attracted increasing attention for its ultra-sensitive to detect the incipient damages in service material by analyzing the amplitude of second harmonic wave. However, the mainstream method of simulating the second harmonic generation (SHG) in nonlinear material is using finite element method with time-domain solver, which is extremely time-consuming and can hardly simulate the huge and complex structures. In this paper, we propose a flexible finite element method based on frequency solver to simulate the SHG. The primary wave field, the second harmonic wave field and the static component field are separately set. This method is realized in Comsol Multiphysics software, the case of the SHG in plate indicates that the calculation efficiency has been significantly improved in compare with the time domain solver, whereas the results of time-domain solver and frequency domain solver have good agreement with each other. This method can be easily applied in the SHG analysis in huge and complex structures. Moreover, the primary wave field, the second harmonic wave field and the static component field can be respectively presented in the post-processing to help provide more information about physical insight of SHG.

In silico Identification of MHC Displayed Tumor Associated Peptides in Ovarian Cancer for Multi-Epitope Vaccine Construct.

Recognizing the potential of the immune system, immunotherapies have brought about a revolution in the treatment of cancer. Low tumour mutational burden and strong immunosuppression in the peritoneal tumor microenvironment (TME) lead to poor outcomes of immune checkpoint inhibition (ICI) and CART cell therapy in ovarian cancer. Alternative immunotherapeutic strategies are of utmost importance to achieve sound clinical success. The development of peptide vaccines based on tumor-associated antigens (TAAs) for ovarian cancer cells can be a potential target to provoke an anti-tumor immune response and subsequent clearance of tumour cells. The purpose of this in silico study was to find potential epitopes for a multi-epitope vaccine construct using the immunopeptidomics landscape of ovarian carcinoma. The four TAAs (MUC16, IDO1, FOLR1, and DDX5) were selected for potential epitopes prediction. The epitopes for B-cells, helper T-lymphocytes (HTL), and Cytotoxic Tlymphocytes (CTL) were predicted on the basis of antigenic, allergenic, and toxic properties. These epitopes were combined with suitable linkers and an adjuvant to form a multi-epitope construct. Four HTLs, 13 CTLs, and 6 potential B-cell epitopes were selected from the predicted epitope. The designed multi-epitope construct was potentially immunogenic, non-toxic, and non-allergenic. Physicochemical properties and higher-order structural analyses of the final construct revealed a potential vaccine candidate. The designed vaccine construct has the potential to trigger both humoral and cellular immune responses and may be employed as a therapeutic immunization candidate for ovarian malignancies. However, further in vitro and animal experimentation is required to establish the efficacy of the vaccine candidate.

Energy absorption performance of Kresling origami tubes under impact loading

Thin-walled tubes with an origami design, particularly the Kresling pattern, exhibit superior mechanical properties compared to traditional straight tubes, including a more constant reaction force and predictable deformation. Despite their potential, research on these patterned structures, especially when made from structural materials like metal and tested under dynamic conditions, remains limited. This study investigates the compressive performance of aluminium Kresling origami tubes (KOTs) under quasi-static and impact scenarios (up to 30 m/s) in the axial direction. Results show that increased impact velocity leads to more localized deformation and improved energy absorption metrics. A validated numerical model was used to analyze the influence of hierarchy rotation, sector angles, and loading velocity on mechanical performance. Comparisons with Miura-ori patterned tubes and hexagonal cross-section straight tubes of the same relative density revealed that KOTs have superior energy absorption performance. An empirical model was developed to effectively predict the mean crushing stress of KOTs. In addition. a generative machine learning model was introduced to synthesize a large dataset from initial simulations, providing an efficient and reliable solution for energy absorption analysis in origami structures, addressing the challenge of limited specimen datasets.

Efficient 3D temperature field prediction and visualization for AFP process analysis in composite structures

AbstractProcess modeling is an indispensable tool for establishing a foundation for process optimization and enhancing the quality of products. Analyzing the thermoforming process of polymer matrix composites presupposes the acquisition of accurate thermal histories. This paper introduces a numerical solution based on the finite difference (FD) model to predict the temperature field of angle‐ply composite structures during automated fiber placement (AFP) process along the machining trajectory. The proposed method incorporates three‐dimensional hybrid boundary conditions and considers temperature‐dependent material properties, significantly improving efficiency compared to the finite element (FE) model and overcoming challenges related to complex boundary conditions and anisotropic heat transfer in analytical solutions. Real‐time temperature measurement experiments were conducted to validate predictions, and further a specific temperature control strategy that meets process requirements was explored. In summary, the paper introduces a novel approach to address the temperature field in complex composite structure manufacturing processes.Highlights A novel 3D finite difference model predicts the temperature field in automated fiber placement. Improved prediction accuracy by managing complex boundary conditions. Effectively handled anisotropic heat transfer in complex composite structures. Superior efficiency over existing numerical methods. Developed a model‐based strategy for optimal temperature control within ±5°C.

Numerical methods for modal analysis in optical rib waveguide structures: a review

Numerical methods for modal analysis in optical rib waveguide structures: a review

Macro-micro investigation on the coefficient of friction on the interface between steel and cast-in-place UHPC

The interface friction force between steel and Ultra-high performance concrete (UHPC) can significantly enhance the shear loading capacity and fatigue performance of steel-UHPC composite structures. Current research on interface friction primarily focuses on the coefficient of friction (COF) on steel-concrete interface. However, using the COF of steel-normal concrete (NC) interface to assess the steel-UHPC interface performance might be debatable and lack accuracy, due to the substantial differences in material properties and compositions between UHPC and NC. In this study, the COF on the interface between the steel plate and cast-in-place UHPC was investigated, and the effects of the steel plate roughness and interface normal stress on the COF were considered. The COF of steel-UHPC was compared with those of steel-NC. The steel plate surface microstructure was also tested using a microscope after experiments. It is recommended that the COF between UHPC and NC and a natural steel plate should be considered as 0.803 and 0.704, respectively, under interface normal stress levels ranging from 0.5 MPa to 9 MPa. The adopted COF in the existing numerical analyses for steel-UHPC structures was conservative, underestimating the value by 37.73 % to 62.64 % compared to the recommended value in this paper. Moreover, when the steel plate roughness of steel-UHPC specimens increased by 1.324 times, the maximum increase in the COF was 11.75 %. However, when the interface normal stress increased by 17 times, the COF on the steel-UHPC interface decreased by a maximum of 12.57 %. Compared to steel-NC specimens, the COF of steel-UHPC showed a maximum increase of 14.25 % under an interface normal stress of 0.5 MPa and 12.98 % under an interface normal stress of 9 MPa.

Structural Analysis of a 4-Layer Curved Alternating Gradient Canted-Cosine-Theta Magnet Applied for Light-Weight Gantry

Structural Analysis of a 4-Layer Curved Alternating Gradient Canted-Cosine-Theta Magnet Applied for Light-Weight Gantry

A staggered local damage model for fracture analysis in bi-material structures

This article is devoted to extension of the recently developed enhanced local damage model for failure prediction in bi-material structures. Compared to non-local models, the enhanced local model offers lower computational cost while the inherent mesh-dependency issue is treated. By defining equivalent strain based on the bi-energy norm concept and Mazars’s criterion, which considers both tensile and compressive strain components, the model aligns with the behavior of quasi-brittle materials. The state of material point is indicated by a damage parameter, ranging from 0 to 1, to represent the evolution from being fully intact to complete failure. An efficient staggered scheme is introduced, in which the equilibrium equation and the update of damage parameter are decoupled. The proposed model is validated with a series of three-point bending experimental tests on PMMA/Al6061 specimens reported by Lee and Krishnaswamy (2000). Good agreement is observed between the proposed model and experimental data, as well as numerical results from other authors, in crack path prediction.

Dimension reduction and homogenization of composite plate with matrix pre-strain

This paper focuses on the simultaneous homogenization and dimension reduction of periodic composite plates within the framework of non-linear elasticity. The composite plate in its reference (undeformed) configuration consists of a periodic perforated plate made of stiff material with holes filled by a soft matrix material. The structure is clamped on a cylindrical part. Two cases of asymptotic analysis are considered: one without pre-strain and the other with matrix pre-strain. In both cases, the total elastic energy is in the von-Kármán (vK) regime ( ε 5 ). A new splitting of the displacements is introduced to analyze the asymptotic behavior. The displacements are decomposed using the Kirchhoff–Love (KL) plate displacement decomposition. The use of a re-scaling unfolding operator allows for deriving the asymptotic behavior of the Green St. Venant’s strain tensor in terms of displacements. The limit homogenized energy is shown to be of vK type with linear elastic cell problems, established using the Γ-convergence. Additionally, it is shown that for isotropic homogenized material, our limit vK plate is orthotropic. The derived results have practical applications in the design and analysis of composite structures.

Thermo-Mechanical Properties of Particulate Banana Epoxy Composite with Fruit Waste (Dragon Fruit Peel) Micro Filler for Household Applications

This study evaluates the thermo-mechanical characteristics of eco-friendly composite made of particulate banana fiber (reinforcement), epoxy resin (matrix) and dragon fruit peel powder (micro filler). The composites were developed using compression moulding technique with 3 factors, 4 variations and Taguchi orthogonal array design (L16). The proposed filler characterization results revealed that the density was 0.97 g/cm3 and combination of C–O, Ca–O, and Ca–Co could improve mechanical strength. Composites with 5 mm fiber length, 40 wt.% fiber weight, and 15 wt.% filler weight have a maximum tensile strength of 25.58 MPa, flexural strength of 44.47 MPa, impact strength 180.33 J/m, and hardness of 82.50 SD. The best composite’s thermal, wear, water and fatigue studies were proposed to suit household applications. The proposed filler improves fiber-resin bonding, which increases thermal stability to 245 °C, wear resistance, decreases water absorption, and results in a fatigue life count of 121000 cycles. Thus, this study concluded that the increasing filler content and decreasing particulate size had an impact on the thermo-mechanical characteristics of banana-reinforced polymeric composites. As a result, an eco-friendly polymeric composite mixer coupler model was developed. Comparative structural and model analyses were performed using ANSYS R17.2. The analysis results confirmed that the proposed composite had higher natural frequencies of 2766.5 Hz and lower deformation values of 0.089293 mm. This proves the proposed eco-friendly composite is a suitable replacement for a synthetic mixer coupler.

A Case Study of Problem-Based Learning from a Civil Engineering Structural Analysis Course

A Case Study of Problem-Based Learning from a Civil Engineering Structural Analysis Course

Structure of the human systemic RNAi defective transmembrane protein 1 (hSIDT1) reveals the conformational flexibility of its lipid binding domain.

In C. elegans, inter-cellular transport of the small non-coding RNA causing systemic RNA interference (RNAi) is mediated by the transmembrane protein SID1, encoded by the sid1 gene in the systemic RNA interference-defective (sid) loci. SID1 shares structural and sequence similarity with cholesterol uptake protein 1 (CHUP1) and is classified as a member of the cholesterol uptake family (ChUP). Although systemic RNAi is not an evolutionarily conserved process, the sid gene products are found across the animal kingdom, suggesting the existence of other novel gene regulatory mechanisms mediated by small non-coding RNAs. Human homologs of sid gene products - hSIDT1 and hSIDT2 - mediate contact-dependent lipophilic small non-coding dsRNA transport. Here, we report the structure of recombinant human SIDT1. We find that the extra-cytosolic domain (ECD) of hSIDT1 adopts a double jelly roll fold, and the transmembrane domain (TMD) exists as two modules - a flexible lipid binding domain (LBD) and a rigid TMD core. Our structural analyses provide insights into the inherent conformational dynamics within the lipid binding domain in cholesterol uptake (ChUP) family members.

Network structures of internet gaming disorder and gaming disorder: Symptom operationalization causes variation.

From 2022, the International Classification of Diseases, eleventh edition (ICD-11) includes the first mental disorder based on digital technology, "gaming disorder," which was previously suggested as a condition for further examination in the Diagnostic and Statistical Manual of Mental Disorders, fifth edition (DSM-5). In this cross-sectional study, we provide the first large-scale network analysis of various symptom structures for these constructs to understand the complex interconnections between their proposed symptoms. Culturally diverse samples of 2,846 digital game players (M = 25.3 years) and 746 esports players (M = 23.5 years) were recruited. A network approach was applied to explore a multiverse of gaming disorder symptom structures, effects of item operationalization, and possible external moderators. Gaming disorder was measured using the Internet Gaming Disorder Scale 9-Short Form (IGDS9-SF), Gaming Disorder Test, and several items borrowed from Chinese Internet Gaming Disorder Scale, Personal Internet Gaming Disorder Evaluation-9, and Clinical Video game Addiction Test 2.0 scales. Two symptoms (loss of control and continued use despite problems) present in both, the DSM-5 and ICD-11, were systematically central to most of the analyzed networks. Alternative operationalizations of single items systematically caused significant network differences. Networks were invariant across groups of play style, age, gender, gaming time, and most of the psychosocial characteristics. Our results caution practitioners and researchers when studying and interpreting gaming disorder symptoms. The data indicate that even minor operational changes in symptoms can lead to significant network-level changes, thus highlighting the need for careful wording. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Towards Faithful Model Explanation in NLP: A Survey

Abstract End-to-end neural Natural Language Processing (NLP) models are notoriously difficult to understand. This has given rise to numerous efforts towards model explainability in recent years. One desideratum of model explanation is faithfulness, that is, an explanation should accurately represent the reasoning process behind the model’s prediction. In this survey, we review over 110 model explanation methods in NLP through the lens of faithfulness. We first discuss the definition and evaluation of faithfulness, as well as its significance for explainability. We then introduce recent advances in faithful explanation, grouping existing approaches into five categories: similarity-based methods, analysis of model-internal structures, backpropagation-based methods, counterfactual intervention, and self-explanatory models. For each category, we synthesize its representative studies, strengths, and weaknesses. Finally, we summarize their common virtues and remaining challenges, and reflect on future work directions towards faithful explainability in NLP.

Partial Force Calculation and Structural Strength Analysis of Null-Flux Coil for Superconducting Electrodynamic Suspension Train

Partial Force Calculation and Structural Strength Analysis of Null-Flux Coil for Superconducting Electrodynamic Suspension Train