Structural Elements Research Articles

Role of individual structural and functional elements of myelin in Parkinson’s disease

Role of individual structural and functional elements of myelin in Parkinson’s disease

Impact of Various High Intensity Earthquake Characteristics on the Inelastic Seismic Response of Irregular Medium-Rise Buildings

In the twenty-first century, the seismic design of buildings seems to have become a fully recognized topic. There are guidelines and standards which should be taken into account by designers in seismic areas. Designers using modern international guidelines have ascertained that the behavior of structures is not as expected. New challenges in the construction industry result in the construction of structures with new, unusual shapes. These are structures that do not meet the assumptions of safe construction in seismic areas. Contemporary buildings are also characterized by their irregular distribution of structural elements. Such solutions are not beneficial from the point of view of seismic engineering and can lead to reduced dynamic resistance and damage in such structures. In this paper, a five-storey, irregular-shaped reinforced concrete (RC) building model was subjected to different earthquakes with varying magnitudes, PGA (peak ground acceleration) and PGV (peak ground velocity) values, and durations of the intense shock phase. Once the model was verified using previous in situ measurements, the building model was subjected to five earthquakes. A numerical nonlinear analysis of the building was performed using a verified FEA (finite element analysis) model in the time domain through non-linear time history analysis with the Broyden–Fletcher–Goldfarb–Shanno (BFGS) method. The building’s dynamic properties were measured using various methods of excitation. The model was influenced, among others, by two far-field representative events caused by the last earthquake in Turkey, which resulted in strong ground motion. The analysis results identified the locations of structural damage and allowed for the assessment of the structure’s dynamic resistance. The results of the calculations prove that the duration of the intensive phase of extortion is one of the reasons for building damage in earthquake-prone areas. Building damage occurs with earthquakes that are characterized by an intensive phase of excitation with a long duration and high values of velocity in the earthquake components. The article highlights the inadequate dynamic resistance of the building, leading to excessive displacements and unfavorable structural solutions. Damage to buildings at this earthquake intensity caused damage to the load-bearing structure, which was not designed for such intensities. This paper is a research report with a specific case study of medium-rise irregular RC buildings.

Self-supporting thin Shells in Italy. Space and Structure of the Industrial Buildings (1930-1970)

In the Twentieth Century, the industrial buildings featured a broad experimentation on the load-bearing structures suited to the production spaces. Among the structural elements explicitly designed for factories were reinforced concrete thin shells. In Italy, where reinforced concrete was the predominant construction technique for the entire century, the evolution of the thin shells for industrial buildings traced a significant story: starting from the introduction of foreign systems and patents in the 1920s, the design and construction of the thin shells gradually stacked to national productive and technological specificities. This paper presents a historical investigation of the application of thin shells in Italy between 1930 and 1970, remarking, thus, the local contribution of Italian contractors and designers in the evolution of both the design solutions and production process. Furthermore, the study presents a systematic historical and technical framework related to thin shells to support the actions of knowledge and safeguard the industrial building heritage.

Two-Staged Technology for CoCr Stent Production by SLM

Additive manufacturing of porous materials with a specific macrostructure and tunable mechanical properties is a state-of-the-art area of material science. Additive technologies are widely used in industry due to numerous advantages, including automation, reproducibility, and freedom of design. Selective laser melting (SLM) is one of the advanced techniques among 3D fabrication methods. It is widely used to produce various medical implants and devices including stents. It should be noticed that there is a lack of information on its application in stent production. The paper presents the technological aspects of CoCr stent SLM fabrication, including design of stents and development of regimes for their manufacturing. Physical, chemical, and technological properties of CoCr powder were initially determined. Parametric design of mesh stent models was adopted. A two-stage approach was developed to ensure dimensional accuracy and quality of stents. The first stage involves a development of the single-track fusion process. The second stage includes the stent manufacturing according to determined technological regimes. The single-track fusion process was simulated to assign laser synthesis parameters for stent fabrication. Melting bath temperature and laser regimes providing such conditions were determined. Twenty-seven SLM manufacturing regimes were realized. Dependence of single-tracks width and height on the laser power, exposition time, and point distance was revealed. The qualitative characteristics of tracks imitating the geometry of the stent struts as well as favorable and unfavorable fusion regimes were determined. The results of surface roughness regulating of the stents’ structural elements by various methods were analyzed. Thus, this two-staged approach can be considered as a fundamental approach for CoCr stent SLM fabrication.

Dissecting the Conformational Heterogeneity of Stem-Loop Substructures of the Fifth Element in the 5'-Untranslated Region of SARS-CoV-2.

Throughout the family of coronaviruses, structured RNA elements within the 5' region of the genome are highly conserved. The fifth stem-loop element from SARS-CoV-2 (5_SL5) represents an example of an RNA structural element, repeatedly occurring in coronaviruses. It contains a conserved, repetitive fold within its substructures SL5a and SL5b. We herein report the detailed characterization of the structure and dynamics of elements SL5a and SL5b that are located immediately upstream of the SARS-CoV-2 ORF1a/b start codon. Exploiting the unique ability of solution NMR methods, we show that the structures of both apical loops are modulated by structural differences in the remote parts located in their stem regions. We further integrated our high-resolution models of SL5a/b into the context of full-length 5_SL5 structures by combining different structural biology methods. Finally, we evaluated the impact of the two most common VoC mutations within 5_SL5 with respect to individual base-pair stability.

Barriers and facilitators to culturally sensitive care in general practice: a reflexive thematic analysis

BackgroundThis study investigated the perceived barriers and potential facilitators for culturally sensitive care among general practitioners in Flanders. Understanding these dynamics is crucial for improving healthcare quality and equity.MethodologyTwenty-one in-depth interviews were conducted with Flemish GPs. Braun and Clarke’s reflexive thematic analysis was employed to develop and interpret themes that elucidate shared underlying meanings and capture the nuanced challenges and strategies related to cultural sensitivity in healthcare.ResultsTwo core themes were generated: GPs’ uncertainty and opposition. These themes manifest in emotional responses such as frustration, miscomprehension, and feelings of helplessness, influencing relational outcomes marked by patient disconnect and reduced motivation for cultural sensitivity. The barriers identified are exacerbated by resource scarcity and limited intercultural contact. Conversely, facilitators include structural elements like interpreters and individual strategies such as engagement, aimed at enhancing GPs’ confidence in culturally diverse encounters. A meta-theme of perceived lack of control underscores the challenges, particularly regarding language barriers and resource constraints, highlighting the critical role of GPs’ empowerment through enhanced intercultural communication skills.ConclusionAddressing GPs’ uncertainties and oppositions can mitigate related issues, thereby promoting comprehensive culturally sensitive care. Essential strategies include continuous education and policy reforms to dismantle structural barriers. Moreover, incentivizing culturally sensitive care through quality care financial incentives could bolster GP motivation. These insights are pivotal for stakeholders—practitioners, policymakers, and educators—committed to advancing culturally sensitive healthcare practices and, ultimately, for fostering more equitable care provision.

A New Practical Equation for the Shear Capacity of FRP-RC Slender Beams Assessment via Gene Expression Programming

Due to their advantageous mechanical and physical characteristics, fiber-reinforced polymer (FRP) bars have been used extensively in various structural elements in recent years. Numerous researchers examined the structural behaviour of such elements reinforced with FRP bars to forecast their capacity. Despite a large number of existing code provisions and proposed procedures based on the heuristic methods, a practical yet accurate equation for utilisation by the engineers who are dealing with structural retrofitting and analyzing is not available. Here, a gene expression programming (GEP) based simple algorithm is used in conjunction with an extensive database containing 481 stirrup-free experimental samples that were gathered from tests conducted in the lab. Next, using data from an additional programme, the GEP output is examined in order to produce a workable formula for determining the shear capacity of these members. Lastly, a comparison is done using the current equations. The outcomes show that, in comparison to the current ones, the suggested GEP equation along with the CSA S806-12 code provision yields more accurate values.

Analysis of the Construction Sequence of a Reaction Wall in a Structural Laboratory Supported by the VDC Methodology

The structures laboratory is a crucial facility for supporting research development related to the construction industry. This kind of laboratory has several components, and one of its key components is the reaction wall. The reaction wall supports the execution of experimental tests on structural elements under specific configurations and loads. Constructing a reaction wall presents challenges due to the highest standards to be met. This research analyzes the construction process of a reaction wall at a private university in Peru. Initially, a schedule was proposed by a contractor. However, the client, knowing the complexity of such construction, asked to review the initial schedule to ensure that it would meet the constructability requirements under the integrated product-organization-process approach given by the virtual design and construction (VDC) methodology. The result of this study pointed out the need to revise the original proposed schedule, extending the construction time to 66% due to the lack of construction processes compatible with the requirements for the reaction wall’s execution. Finally, a survey was conducted to observe the learning curve associated with implementing the VDC methodology.

Psychologists' Opportunities for Fostering Leadership Skills in Academic Medicine: The Rothenberger Leadership Academy.

Healthcare leaders must increasingly attend to the monumental challenges facing their organizations (Angood and Falcone, American Association for Physician Leadership, 2023). As such, leadership in healthcare settings demands new skills sets amongst healthcare professionals that transcend the technical skills of any given profession. Academic health center psychologists are well-positioned to contribute to the leadership of academic health centers due to knowledge, skills, and attitudes fostered in doctoral psychology education, practice, and research through the focus on Profession-Wide Competencies. This article calls for psychologists to pursue more leadership opportunities within academic health centers.The article starts by identifying parallels between psychology's Profession-Wide Competencies and needed leadership skills/concepts for healthcare leaders. An example of an academic health center psychologist's leadership in a cohort-based physician leadership program illustrates how Profession-Wide Competencies were used in three structural elements of the leadership program. The article identifies particular leadership opportunities for psychologists within academic health centers.

Characterization, Codon Usage Pattern and Phylogenetic Implications of the Waterlily Aphid Rhopalosiphum nymphaeae (Hemiptera: Aphididae) Mitochondrial Genome

The water lily aphid, Rhopalosiphum nymphaeae, is the only known aphid that can live in both terrestrial and aquatic conditions. In this study, the complete mitochondrial genome of R. nymphaeae was generated using Illumina sequencing technology. The typical circular DNA mitochondrial genome of R. nymphaeae is 15,772 bp in length, with a high A+T content (84.34%). It contains 37 coding genes (13 protein-coding genes, 22 transport RNAs, and two ribosomal RNAs) and two non-coding regions (one control region and one repeat region). Enc-plot, PR2-bias, and neutrality plot analysis indicated that the codon usage of the protein-coding genes is mainly affected by natural selection. The evolution rate analysis (the ratio of nonsynonymous to synonymous, Ka/Ks) indicated that all the PCGs in R. nymphaeae are under a strong purifying selection. The control region has conserved structure elements, and two types of tandem repeat units exist. The length and sequence of the aphid-unique repeat region has high similarity with closely related species. Phylogenetic analyses determined by both maximum likelihood and Bayesian inference support the monophyly of Aphidinae, Aphidini, Aphidina, and Rhopalosiphina. However, the monophyly of the genera in Rhopalosiphina, such as Rhopalosiphum, is still not resolved. This study may help us to understand the phylogenetic relationship of aphids, and much more aphid data are needed in future studies.

Anodic Synthesis of Highly Ordered TiO2 Nanotube Arrays: Role of Electrolyte Composition on the Structural, Morphological, Optical, and Photo-electrochemical Properties

The fluoride species present in two different anodizing electrolytes were used to produce TiO2 nanotube arrays (TiO2 NTAs) by simultaneous anodic reaction and chemical dissolution. In this investigation, two different electrolytes were used for the preparation; [Eth-TiO2 NAs: 95 ml ethylene glycol+0.5% NH4F+5 ml DI water] and [Gly-TiO2 NAs: 75 ml glycerine+0.5% NH4F+25 ml DI water]. The effects of the prepared electrolytes used in the synthesis of TiO2 nanotube arrays on structural element composition, morphology, and optical properties are the focus of this study and are characterized by X-ray diffraction (XRD), scanning electron microscopy field emission (FE-SEM), energy-dispersive X-ray spectroscopy (EDX) and UV-vis diffusion reflection spectroscopy (DRS), respectively. The photoelectrochemical properties of TiO2 NTAs prepared in different electrolytes were investigated. The photoelectrochemical performance of TiO2 NTAs in Na2SO3 (0.1 M) and Na2S (0.1) was examined under the light of 100 mW/cm2 from a xenon lamp. Comparing the photoelectrochemical (PEC) results of both electrolytes, we find that Eth-TiO2 NTAs contribute a wide surface area resulting in an enhanced PEC response. TiO2 NTs, which were prepared with Eth-TiO2 NTAs, exhibited the highest photocurrent density, 0.326 mA cm–2, and photoconversion efficiency (0.22%).

Translation regulation by RNA stem-loops can reduce gene expression noise

BackgroundStochastic modelling plays a crucial role in comprehending the dynamics of intracellular events in various biochemical systems, including gene-expression models. Cell-to-cell variability arises from the stochasticity or noise in the levels of gene products such as messenger RNA (mRNA) and protein. The sources of noise can stem from different factors, including structural elements. Recent studies have revealed that the mRNA structure can be more intricate than previously assumed.ResultsHere, we focus on the formation of stem-loops and present a reinterpretation of previous data, offering new insights. Our analysis demonstrates that stem-loops that restrict translation have the potential to reduce noise.ConclusionsIn conclusion, we investigate a structured/generalised version of a stochastic gene-expression model, wherein mRNA molecules can be found in one of their finite number of different states and transition between them. By characterising and deriving non-trivial analytical expressions for the steady-state protein distribution, we provide two specific examples which can be readily obtained from the structured/generalised model, showcasing the model’s practical applicability.

Plate buckling analysis in peridynamic framework

AbstractPeridynamics (PD) is a generalized continuum theory that is developed to account for long range internal force/moment interactions. PD equations of motion are of the integro‐differential type, and only several closed‐form analytical solutions are available for elementary structures. In this paper, governing equations for stability of Kirchhoff type (shear rigid) plates in the PD framework are derived. For several types of boundary conditions, closed form analytical solutions for the buckling loads are presented. The results are compared with the solutions according to the classical plate theory. A very good agreement between the non‐local and the classical theories is observed for the case of the small horizon sizes which shows the capability of the developed approach.

Genome-Wide Identification and Characterization of the Aux/IAA Gene Family in Strawberry Species

Auxin is the first plant hormone found to play a dominant role in fruit growth, from fruit set to fruit ripening. Strawberry plants represent a suitable model for studying auxin’s biosynthesis, sensing, and signaling machinery. Aux/IAA genes are a classical rapid auxin-responsive family. However, the Aux/IAA gene family in Fragaria genus is poorly understood. In this study, a total of 287 Aux/IAA genes were identified in the eight strawberry genomes. Their physicochemical properties, domain structure, and cis-regulatory elements revealed the functional multiplicity of the strawberry Aux/IAAs. We used a phylogenetic analysis to classify these genes into 12 classes. In addition, based on synteny analysis, gene duplications, and calculation of the Ka/Ks ratio, we found that segmental duplications promote the evolution of Aux/IAAs in Fragaria species, which is followed by purifying selection. Furthermore, the expression pattern and protein–protein interaction network of these genes in Fragaria vesca revealed various tissue-specific expressions and probable regulatory functions. Taken together, these results provide basic genomic information and a functional analysis of these genes, which will serve to expand our understanding of the direction in which the Aux/IAA gene family is evolving in Fragaria species.

Flammability and Mechanical Testing of Sandwich Composite for Rolling Stock Structural Applications

Components made of composite materials are being increasingly used in the construction of rolling stock. Currently, the use of components made of composite materials as train structural elements is increasingly being considered. Non-structural components made of composites are most often found inside rail vehicles (e.g., the interior lining), while structural components made of sandwich composite materials can be used for the roof, sidewalls, and underframe constructions. This article provides a description of an innovative sandwich composite developed for a metro’s underframe, as well as the production process and preparation of the composite specimens. The main parts of the work are flammability and mechanical (static and fatigue) tests of the innovative sandwich composite. The scope of the flammability tests included the testing of the fire properties using the radial plate method, the optical density of smoke, and the content of toxic gases. The mechanical strength of the sandwich composite was examined during a flexural (three-point bending) test and a fatigue strength under a given dynamic load. The results presented in the article are very significant, both in terms of flammability and the mechanical strength tests. In order to produce large-size train components, appropriately large patches of component layers of the composite are required; this may pose production problems.

Comparison of Actual Deformations of Historic Wooden Structures with Values Obtained from Static Calculations

In historic wooden structures, deformations can be influenced by factors that are negligible within the first 50 years of the building's existence. In attics where the roof covering is made of metal sheets, the air and structural elements heat up during the day and cool down rapidly at night. This phenomenon, over a long period, can cause micro-cracks and surface material degradation. For the study, historic buildings meeting the criteria for service class II according to PN-EN 1995-1-1 were selected. Measurements of deflections, humidity, and modulus of elasticity of the wood were conducted. The actual deflections of the examined structures were found to be 28% to 37% higher than those obtained from numerical calculations, indicating ongoing rheological processes in the wooden structures.

Physical, Mechanical, and Flammability Properties of Wood-Plastic Composites (WPC) Containing Beech-Wood Flour and Flame-Retardant Additives.

This study aims to develop a recyclable, economical, and flame-retardant composite material using polypropylene, beech flour, tetrabromobisphenol A bis (TBBPA), and antimony trioxide (ATO). Flame-retardant additives (TBBPA and ATO) were initially added into polypropylene at different rates, and masterbatch (MB) samples were produced by the extrusion method. Subsequently, different percentages of wood flour (10%, 15%, 20%, 25%, and 30%) along with 60% MB were added to the polypropylene to create wood-polymer composites (WPC) using the injection method. The TBBPA, ATO, and wood flour were introduced through side-feeding hoppers during injection to ensure a homogeneous distribution within the WPC. Physical, thermal, and mechanical tests were conducted on the WPC samples. Additionally, TGA, FTIR, and SEM analyses were performed. The results indicated that the optimal ratios for TBBPA and ATO additives were 20% and 10%, respectively. It was observed that increasing the wood flour content in the WPC samples led to enhanced density, water absorption, hardness, impact, and abrasion resistance. Conversely, MFI, bending strength, and tensile strength decreased with higher wood flour content. It was observed that WPC samples exhibited flame resistance up to 725 °C. The produced WPC materials can be used in flooring applications, interior furniture, decorative wall panels, and aesthetic structural elements due to their fire behavior, good mechanical properties, low water-absorption rates, and aesthetic appearance.

Cooperative Substructure and Energetics of Allosteric Regulation of the Catalytic Core of the E3 Ubiquitin Ligase Parkin by Phosphorylated Ubiquitin.

Mutations in the parkin gene product Parkin give rise to autosomal recessive juvenile parkinsonism. Parkin is an E3 ubiquitin ligase that is a critical participant in the process of mitophagy. Parkin has a complex structure that integrates several allosteric signals to maintain precise control of its catalytic activity. Though its allosterically controlled structural reorganization has been extensively characterized by crystallography, the energetics and mechanisms of allosteric regulation of Parkin are much less well understood. Allostery is fundamentally linked to the energetics of the cooperative (sub)structure of the protein. Herein, we examine the mechanism of allosteric activation by phosphorylated ubiquitin binding to the enzymatic core of Parkin, which lacks the antagonistic Ubl domain. In this way, the allosteric effects of the agonist phosphorylated ubiquitin can be isolated. Using native-state hydrogen exchange monitored by mass spectrometry, we find that the five structural domains of the core of Parkin are energetically distinct. Nevertheless, association of phosphorylated ubiquitin destabilizes structural elements that bind the ubiquitin-like domain antagonist while promoting the dissociation of the catalytic domain and energetically poises the protein for transition to the fully activated structure.

Seismic analysis of bridge with buckling‐restrained brace posttensioned concrete pier

AbstractA two‐span bridge built with a two‐column pier consisting of unbonded posttensioned precast concrete columns and a buckling‐restrained brace (BRB) is analyzed using a three‐dimensional nonlinear numerical model. Seismic damage to the pier is eliminated through rocking of the posttensioned columns and seismic energy dissipation by the BRB. The numerical model is calibrated with experimental results of posttensioned columns and BRB structural elements. Seismic assessment of the bridge pier is performed using the ratio of BRB axial force to base shear as the parameter of interest. Limits for the seismic performance of the bridge pier are established by means of nonlinear static analysis using OpenSees. Bidirectional ground motions are used to perform probabilistic hazard analysis through nonlinear time history simulations. Three damage limit states are defined in this research: the activation point of posttensioning bars, the maximum base shear capacity or onset of concrete spalling, and collapse defined as the state at 20% loss of maximum base shear capacity. The analysis results are formulated into fragility curves for the three damage states as well as the residual drift. The fragility curves could be used for preliminary seismic bridge design. The analysis shows that the BRB dissipates significant seismic energy and the posttensioned concrete columns reduce residual displacements so that the bridge pier can remain functional after severe earthquakes. The fragility approach for designing bridge piers constructed with posttensioned concrete columns and BRB elements is a significant improvement over conventional seismic bridge design and can contribute to functional recovery after severe earthquakes.

Performance of RC beams strengthened using NSM FRP and cement based adhesives after exposure to elevated temperatures

A popular method for strengthening of reinforced concrete (RC) structures is the use of carbon fiber reinforced polymers (CFRP) bonded to the structural elements using the near surface mounted (NSM) techniques. While this method possesses many advantages, poor fire resistance as a result of the low glass transition temperatures (TG) of organic resins remains a significant drawback. Replacement of organic resins with cement based adhesives (CBA) could potentially improve the fire performance of NSM FRP systems and reduce the amount of insulation required to achieve the required fire endurance period. This paper presents an experimental program consisting of fifteen RC beams strengthened in flexure using NSM FRP bonded using CBA and subjected to the standard fire time temperature curve up to a target temperature of 600 °C. Twelve of the beams were strengthened using NSM-FRP laminates and bars including both smooth and rough FRP laminates and the remaining three specimens acted as control beams. Further, the use of plasterboard was explored as fire protection to further increase the residual strength of the specimens after heating. Results showed that the reinforced concrete beams strengthened with NSM CFRP retained 82 % to 61 % of their unheated strengthened ultimate load after heat exposure. This was a result of the superior performance of the cement-based adhesive at high temperature and the fire protection provided to the CFRP through embedment in the grooves. Moreover, the use of plasterboard as fire protection decreased the CFRP temperature by 42–24 %. The insulated beams behaved similarly to strengthened beams prior to fire exposure.