bluuebunny/crossref_metadata_2025 huggingface dataset:
Debilitating hip degeneration in trichothiodystrophy: Association with ERCC2/XPD mutations, osteosclerosis, osteopenia, coxa valga, contractures, and osteonecrosis
Authors: DiGiovanna John J. , Randall Grant , Edelman Alexandra , Allawh Rina , Xiong Michael , Tamura Deborah , Khan Sikandar G. , Rizza Elizabeth R. H. , Reynolds James C. , Paul Scott M. , Hill Suvimol C. , Kraemer Kenneth H.
Published: September 2022

Trichothiodystrophy (TTD) is a rare, autosomal recessive, multisystem disorder of DNA repair and transcription with developmental delay and abnormalities in brain, eye, skin, nervous, and musculoskeletal systems. We followed a cohort of 37 patients with TTD at the National Institutes of Health (NIH) from 2001 to 2019 with a median age at last observation of 12 years (range 2–36). Some children with TTD developed rapidly debilitating hip degeneration (DHD): a distinctive pattern of hip pain, inability to walk, and avascular necrosis on imaging. Ten (27%) of the 37 patients had DHD at median age 8 years (range 5–12), followed by onset of imaging findings at median age 9 years (range 5–13). All 10 had mutations in the ERCC2/XPD gene. In 7 of the 10 affected patients, DHD rapidly became bilateral. DHD was associated with coxa valga, central osteosclerosis with peripheral osteopenia of the skeleton, and contractures/tightness of the lower limbs. Except for one patient, surgical interventions were generally not effective at preventing DHD. Four patients with DHD died at a median age of 11 years (range 9–15). TTD patients with ERCC2/XPD gene mutations have a high risk of musculoskeletal abnormalities and DHD leading to poor outcomes. Monitoring by history, physical examination, imaging, and by physical medicine and rehabilitation specialists may be warranted.
Photochemical C(sp2)−H Pyridination via Arene–Pyridinium Electron Donor–Acceptor Complexes
Authors: Lasky Matthew R. , Salvador Tolani K. , Mukhopadhyay Sukrit , Remy Matthew S. , Vaid Thomas P. , Sanford Melanie S.
Published: September 2022

This report describes the development of a photochemical method for C(sp2)−H pyridination that leverages the photoexcitation of electron donor–acceptor (EDA) complexes. Experimental and DFT studies show that black light (λmax≈350 nm) irradiation of solutions of protonated pyridines (acceptors) and aromatic C−H substrates (donors) results in single electron transfer to form aryl radical cation intermediates that can be trapped with pyridine nucleophiles under aerobic conditions. With some modification of the reaction conditions, this EDA activation mode is also effective for promoting the oxidatively triggered SNAr pyridination of aryl halides. Overall, this report represents an inexpensive and atom‐economical approach to photochemical pyridination reactions that eliminates the requirement of an exogenous photocatalyst.
Chemical Synthesis, Characterization, and Properties of Multi‐Element Nanoparticles
Authors: Kusada Kohei , Mukoyoshi Megumi , Wu Dongshuang , Kitagawa Hiroshi
Published: September 2022

Multi‐element nanoparticles (NPs) consisting of five or more elements have been increasingly studied in the past five years. Their emergence is taking materials science one step further because they exhibit superior properties to those of conventional NPs in a range of respects, including catalysis. This Review focuses on the recent progress in multi‐element NPs regarding synthesis, especially with regard to chemical synthesis, characterization, and properties. We begin with a brief introduction of multi‐element NPs and an overview of their synthesis methods. Then, we present representative examples of multi‐element alloy NPs and ceramic NPs, including oxide NPs prepared by chemical syntheses. This Review intends to provide useful insights into the chemical methods that are used to synthesize multi‐element NPs, and includes a discussion on the possibilities arising from their use in new functional materials.
Stereomodulation of Poly(4‐methyl‐1‐pentene): Adoption of a Neglected and Misunderstood Commercial Polyolefin
Authors: Wentz Charlotte M. , Fischbach Danyon M. , Sita Lawrence R.
Published: September 2022

A toolbox of living coordination polymerization methods based on CPAM group 4 metal initiators has been applied for the stereomodulation of poly(4‐methyl‐1‐pentene) (PMP) tacticity to provide new fundamental forms in which thermal phase transitions, Tg and Tm, can be adjusted over a wide range. Also reported for the first time are the synthesis and properties of authenticated 1,2‐regioregular atactic PMP, which serves to correct past errors regarding this fundamental polyolefin.
N‐2‐hydroxypropyl trimethyl ammonium chloride chitosan‐glycerol complex temperature‐sensitive hydrogel for wound dressing
Authors: Wang Hongli , Yan Xingye , Jin Zheng , Wang Yiyu , Lin Yuhong , Zhao Kai
Published: September 2022

With the development of the times, it becomes difficult or even impossible for traditional wound dressings to meet people's needs for high‐quality wound repair and management. Therefore, there is an urgent need for new biomedical dressings that can accelerate wound healing in clinical practice. In this study, N‐2‐hydroxypropyl trimethylammonium chloride chitosan (N‐2‐HACC), a derivative of chitosan, was used as raw material to sprepare N‐2‐HACC temperature sensitive hydrogel. The structure, thermal stability and water content of N‐2‐HACC temperature sensitive hydrogel were analyzed by Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, and differential scanning calorimetry. The safety of N‐2‐HACC temperature sensitive hydrogel was evaluated by in vitro cell assay and in vitro degradation assay, and the effect of N‐2‐HACC temperature sensitive hydrogel on wound healing was evaluated by wound healing experiment in SD rats. The results show that N‐2‐HACC hydrogel, as a wound dressing, has the characteristics of good biocompatibility, good biodegradation, non‐toxic, anti‐inflammatory and so on. It plays a barrier role in the process of wound healing, provides a moist environment for the wound and accelerates wound healing. Therefore, N‐2‐HACC hydrogel has a broad application prospect in promoting wound healing as a wound dressing.
Targeting CD38 to Suppress Osteoarthritis Development and Associated Pain After Joint Injury in Mice
Authors: Gil Alabarse Paulo , Chen Liang‐Yu , Oliveira Patricia , Qin Huaping , Liu‐Bryan Ru
Published: September 2022

Objective

This study was undertaken to determine the role of CD38, which can function as an enzyme to degrade NAD+, in osteoarthritis (OA) development.

Methods

Human knee cartilage from normal donors and OA donors were examined for CD38 expression. “Gain‐of‐function,” through overexpression of CD38 via transient transfection, and “loss‐of‐function,” through pharmacologic inhibition of CD38, approaches were used to assess the effects of CD38 on intracellular NAD+:NADH ratio and catabolic activity in chondrocytes. We also initiated joint injury–induced OA by surgical destabilization of the medial meniscus (DMM) in CD38 knockout mice and wild‐type (WT; C57BL/6) mice and in WT male mice in the presence or absence of apigenin treatment. Cartilage degradation, synovial inflammation, subchondral bone changes, and pain behavior were evaluated after DMM surgery. We also examined expression of CD38 and the neuropeptide calcitonin gene‐related peptide (CGRP) in knee sections from these mice.

Results

CD38 expression was up‐regulated in human knee OA cartilage and in chondrocytes stimulated with the proinflammatory cytokine interleukin‐1β (IL‐1β). Overexpression of CD38 in chondrocytes resulted in reduced cellular NAD+:NADH ratio and augmented catabolic responses to IL‐1β. These effects were reversed by pharmacologic inhibition of CD38. Cartilage degradation and synovial inflammation, associated with increased CD38 expression in cartilage and synovium, osteophyte formation and subchondral bone sclerosis, and pain‐like behavior linked to increased CGRP expression in the synovium were observed in WT mice after joint injury. Such effects were significantly reduced in mice deficient in CD38 through either genetic knockout or pharmacologic inhibition.

Conclusion

CD38 deficiency exerts OA disease–modifying effects. Inhibition of CD38 has the potential to be a novel therapeutic approach for OA treatment.
A multi‐year evaluation of medical student performance on and perceptions of collaborative gross anatomy laboratory examinations
Authors: VanLeuven Ariel J. , Szymik Brett G. , Ramsey Lynn M. , Hesse DeLoris Wenzel
Published: September 2022

Collaborative testing and its benefits have been reported in diverse disciplines across different types of academic institutions. However, there has been minimal research conducted on collaborative assessments in medical schools, particularly in the gross anatomy laboratory. The objectives of this study were to explore the effect of collaborative anatomy laboratory examinations on student performance and to gauge student perceptions of this assessment format. This study examined five academic years of medical students' performance on a two‐stage, collaborative anatomy laboratory examination wherein each student's overall score was a weighted combination of scores from the individual and team examination. Analyses of a descriptive survey capturing students' perceptions of the assessment method were also performed. Individual examination averages increased since implementing the collaborative assessment (p < 0.001), and team examination averages were higher than individual examination averages (p < 0.001). Teams outperformed each of their team members 98% of the time. Teams had a greater than 0.90 incidence of answering a question correctly if more than one person in the group got the answer correct on the individual portion, and a 0.66 incidence of answering correctly if only one person in their group answered correctly on the individual portion. Student feedback identified the discussions and learning that took place during the team portion to be a beneficial feature of this assessment format. Students also reported that this collaborative assessment made them feel a higher level of responsibility to perform well, and that it improved their understanding of gross anatomy.
Has pedagogy, technology, and Covid‐19 killed the face‐to‐face lecture?
Authors: Evans Darrell J. R.
Published: September 2022

The lecture has been around for centuries and has featured as a popular and frequent component in higher education courses across many disciplines including anatomy. In more recent years, there has been a growing shift toward blended learning and related pedagogies that encourage active participation of students in both face‐to‐face and online learning environments. Unfortunately, in many cases, the lecture, which has typically focused on the transmission of information from educator to student has not been adapted to become a more learner‐oriented approach with opportunities for students to actively interact and engage. As a result, the future of whether the lecture should continue has once again become a center of debate. The consequence of the Covid‐19 pandemic and its aftermath have added to this with institutions now looking to stop all lectures or offer them in an online format only. This commentary argues that lecture‐style components could still feature within face‐to‐face and online provision, but only if they are used sparingly within a blended curriculum, have a defined use that aligns well to learning outcomes, are assessed as the most effective method pedagogically, and importantly integrate approaches and activities that promote student engagement. Anatomy educators have demonstrated for years that they are able to be at the forefront of pedagogical change and evidenced during the pandemic their agile and innovative ability to adapt and do things differently. Therefore, the fate of the lecture, at least in anatomy, may well be in their hands.
Operando Optoelectrochemical Analysis of Single Zinc Dendrites with a Reflective Nanopore Electrode
Authors: Li Guopeng , Mao Jiaxin , Saqib Muhammad , Hao Rui
Published: September 2022

Dendrites can severely impair zinc battery performance. An in‐depth understanding of the dynamic morphology evolution of dendrites with operando approaches is pivotal when addressing these issues. However, in previous studies, the corresponding electrochemical signals are usually ensemble and averaged. It is very challenging to obtain detailed information about the key morphology–performance relationship. Herein, correlated high‐resolution operando optical and electrochemical studies of single dendrites on Pt reflective nanopore electrodes are reported. The zinc deposition and dissolution can be directly imaged by a high NA optical microscope, while corresponding galvanic charging and discharging curves are obtained. The correlated information of morphology changes and dynamic overpotential fluctuations under different circumstances unveils the competition between active growth vs. passivation. The isolated zinc formation at the single dendrite level is also evaluated. The methodology can be further extended to elucidate the direct relationship between dendrite evolution and electrochemical responses in various battery systems.
Understanding the Capacity Fade in Polyacrylonitrile Binder‐based LiNi0.5Mn1.5O4 Cells**
Authors: Mathew Alma , Misiewicz Casimir , Lacey Matthew J. , Heiskanen Satu Kristiina , Mindemark Jonas , Berg Erik , Younesi Reza , Brandell Daniel
Published: September 2022

Binders are electrochemically inactive components that have a crucial impact in battery ageing although being present in only small amounts, typically 1–3 % w/w in commercial products. The electrochemical performance of a battery can be tailored via these inactive materials by optimizing the electrode integrity and surface chemistry. Polyacrylonitrile (PAN) for LiNi0.5Mn1.5O4 (LNMO) half‐cells is here investigated as a binder material to enable a stable electrode‐electrolyte interface. Despite being previously described in literature as an oxidatively stable polymer, it is shown that PAN degrades and develops resistive layers within the LNMO cathode. We demonstrate continuous internal resistance increase in LNMO‐based cells during battery operation using intermittent current interruption (ICI) technique. Through a combination of on‐line electrochemical mass spectrometry (OEMS) and X‐ray photoelectron spectroscopy (XPS) characterization techniques, the degradation products can be identified as solid on the LNMO electrode surface, and no excessive gas formation seen. The increased resistance and parasitic processes are correlated to side‐reactions of the PAN, possibly intramolecular cyclization, which can be identified as the main cause of the comparatively fast capacity fade.
Dietary carbohydrates: Pathogenesis and potential therapeutic targets to obesity‐associated metabolic syndrome
Authors: Akter Salima , Akhter Hajara , Chaudhury Habib Sadat , Rahman MD. Hasanur , Gorski Andrew , Hasan Mohammad Nazmul , Shin Yoonhwa , Rahman Md. Ataur , Nguyen Minh Nam , Choi Tae Gyu , Kim Sung‐Soo
Published: September 2022

Metabolic syndrome (MetS) is a common feature in obesity, comprising a cluster of abnormalities including abdominal fat accumulation, hyperglycemia, hyperinsulinemia, dyslipidemia, and hypertension, leading to diabetes and cardiovascular diseases (CVD). Intake of carbohydrates (CHO), particularly a sugary diet that rapidly increases blood glucose, triglycerides, and blood pressure levels is the predominant determining factor of MetS. Complex CHO, on the other hand, are a stable source of energy taking a longer time to digest. In particular, resistant starch (RS) or soluble fiber is an excellent source of prebiotics, which alter the gut microbial composition, which in turn improves metabolic control. Altering maternal CHO intake during pregnancy may result in the child developing MetS. Furthermore, lifestyle factors such as physical inactivity in combination with dietary habits may synergistically influence gene expression by modulating genetic and epigenetic regulators transforming childhood obesity into adolescent metabolic disorders. This review summarizes the common pathophysiology of MetS in connection with the nature of CHO, intrauterine nutrition, genetic predisposition, lifestyle factors, and advanced treatment approaches; it also emphasizes how dietary CHO may act as a key element in the pathogenesis and future therapeutic targets of obesity and MetS.
Corporate Oversight Claims Gain Traction for ‘Mission Critical’ Business Operations
Authors: Resnick Stephanie , Fuller John C.
Published: September 2022

Stephanie Resnick and John Fuller are co‐chairs of the Directors' & Officers' Liability & Corporate Governance Practice Group at Fox Rothschild LLP. In this article, they discuss research on a trend of cases showing that liability for the failure of the board to oversee operations is becoming more prominent.
An opportunity for remote professional networking to support undergraduate career goals
Authors: Roberts Kiana , Hoyer Gretchen , Harvey Pamela
Published: September 2022

Engagement in research as an undergraduate and the availability of mentorship from peers and professionals are effective strategies for improving retention of students in STEM fields. Undergraduates in Molecular, Cellular, and Developmental Biology at the University of Colorado Boulder enroll in one of two large introductory course‐based undergraduate research experiences (CUREs) as a requirement of the degree. However, more diverse efforts toward formally supporting students seeking to refine their career goals is needed. We designed a networking‐based workshop series aimed at providing access to the current and former students who have been recently successful in achieving relevant educational and career goals. This 5‐week series focused on (1) how to convert a resume to a curriculum vitae, (2) careers that are accessible with a bachelor's degree in the life sciences, (3) types of research opportunities as an undergraduate and as a post‐graduate, (4) the application process and strategies for successful candidacy in medical school applications, and (5) PhD programs and approaches to producing a competitive application. The workshop connected 52 undergraduates with mentors; the majority of participants requested contact information for continued mentoring. Here, we describe the structure of this remote workshop series and highlight results that emphasized the need for such support that may extend beyond pandemic times.
From classroom to clinic: Biochemistry lab for pre‐health majors
Authors: Bolduc Kathryn C. , McCollough Shannon L. , Stoeckman Angela K.
Published: September 2022

Undergraduate laboratory courses are vital for both enhancing student learning and preparing students for their future careers. Despite their importance, laboratory courses are often met with a lack of enthusiasm from students. For pre‐health students specifically, laboratory courses are commonly seen as part of a check‐list that needs to be completed in order to achieve future education or a career, instead of seeing the information that is taught in laboratories as essential preparation. A one‐semester biochemistry laboratory module was designed to demonstrate the real‐life applications of experimental techniques. This laboratory module introduced students to common clinical measurements and included learning metabolite analysis through hands‐on experiments, connections to simulated patient visits, generation of a research question, and implementation of a student‐designed independent experiment. Surveys indicate that this approach was helpful in creating a greater understanding of the applicability of undergraduate laboratory concepts appealing specifically to pre‐health students. Additionally, students found this module to provide a variety of gained benefits, knowledge, and confidence in performing scientific techniques. The outcomes of this laboratory module indicate its success and potential to be used in curricula as an effective way to engage pre‐health students in an undergraduate biochemistry laboratory.
Quality by design‐based development and validation of an HPLC method for simultaneous estimation of pregabalin and piperine in dual drug‐loaded liposomes
Authors: Gupta Isha , Adin Syeda Nashvia , Aqil Mohd. , Mujeeb Mohd. , Sultana Yasmin
Published: September 2022

The current research work describes the development of a rapid HPLC method for the concurrent detection of pregabalin and piperine in dual drug‐loaded nanoformulations. The primary goal was to recognize the chromatographic conditions wherein propitious segregation of the integrants with quality peaks can be attained. An attempt to expound the target analytical profile was made to accomplish this goal, and critical method attributes (CMAs), viz. percentage acetonitrile content, injection volume and pH, which affect critical quality attributes (CQAs), were identified using systemic risk analysis. Box–Behnken design was employed to develop a relationship between CMAs and CQAs, which engenders an analytical design space. Efficient chromatographic separation for pregabalin and piperine was attained using an analytical C18 column and mobile phase comprising acetonitrile–water (pH 6.9; 70:30%, v/v) in an isocratic elution mode with a 1 ml/min flow rate. The elution was descried at an isosbestic wavelength of 221 nm using a photodiode array detector. The International Conference on Harmonization guidelines were adopted for the developed HPLC method. The validated HPLC method can be further utilized for the simultaneous quantification and detection of pregabalin and piperine in other lipid‐based nanopharmaceuticals such as polymeric nanoparticles, nanocrystals, solid‐lipid nanoparticles, metallic nanoparticles, etc., in in vitro and in vivo studies.
A high‐resolution accurate mass approach to identification of graveoline metabolites using ultra‐high‐performance liquid chromatography combined with a photo diode array detector and quadrupole/time‐of‐flight tandem mass spectrometry
Authors: Liu Hao , Guo Siyuan , Xi Shuyi
Published: September 2022

Graveoline is a biologically active ingredient extracted from Ruta graveolens. Current work aimed at investigating in vitro metabolism of graveoline using rat or human liver microsomes and hepatocytes. Graveoline (20 μM) was incubated with nicotinamide adenine dinucleotide phosphate–supplemented rat and human liver microsomes as well as hepatocytes. LC coupled to a photo diode array detector and quadrupole/time‐of‐flight tandem mass spectrometry was used to detect and identify the metabolites. The structures of the metabolites were identified by accurate mass, elemental composition, and indicative fragment ions. A total of 12 metabolites, comprising 6 phase I and 6 phase II metabolites, were obtained. The metabolic pathways included demethylenation, demethylation, hydroxylation, glucuronidation, and glutathion conjugation. The metabolite (M10) produced by opening the ring of the methylenedioxyphenyl moiety was detected as the most abundant in both liver microsomes and hepatocytes, mainly catalyzed by CYP1A2, 2C8, 2C9, 2C19, 2D6, 3A4, and 3A5. This study provides valuable information on the in vitro metabolism of graveoline, which is indispensable for further development and safety evaluation of this compound.
RETRACTED: Trends in the development of the economic system in the Republic of Kazakhstan
Authors: Kaiyrgaliyeva Maira G. , Appakova Gulmira N. , Nesipbekov Erkin N. , Baikadamov Nurken T. , Karimbergenova Madina K.
Published: September 2022

The study of issues of development and modernisation of the existing structure of economy is central to the scientific activity of the Republic of Kazakhstan. The purpose of the study is to consider the trends in the development of the economic system in the territory of the Republic of Kazakhstan. The study used methods of analysis and synthesis of information, the comparative method, induction and deduction and analysis of research papers, which is relevant to the subject matter. The conclusions were drawn that the modernisation and development of the economy of Kazakhstan is a complex step‐by‐step process, which includes: mastering the manufacturing of modern products; renovation of production equipment; organic integration into the latest world innovation processes; requalification of people. The practical significance of the study is that it can be used by theorists and practitioners to investigate the development of the economic system in the Republic of Kazakhstan.
Hyaluronic acid‐g‐lipoic acid granular gel for promoting diabetic wound healing
Authors: Zhang Shixi , Pan Yuqing , Mao Zhiyuan , Zhang Jiahui , Zhang Kunxi , Yin Jingbo , Wang Chen
Published: September 2022

Diabetic patients are prone to developing chronic inflammation after trauma and have persistent nonhealing wounds. Reactive oxygen species (ROS) and recurrent bacterial infections at the site of long‐term wounds also further delay skin wound healing and tissue regeneration. In this study, a granular gel (which exhibits ROS scavenging and antibacterial properties) is fabricated based on hyaluronic acid‐g‐lipoic acid (HA‐LA). Briefly, HA‐LA is synthesized to fabricate HA‐LA microgels, which are further assembled by Ag+ via its coordination effect with disulfide in dithiolane to form a granular gel. The extrudable bulk granular gel possesses a shear‐thinning feature and is immediately restored to a solid state after extrusion, and this can be easily applied to the whole wound area. Therefore, the grafted LA not only allows for the construction of the granular gel but also removes excess ROS from the microenvironment. Additionally, the presence of Ag+ realizes the assembly of microgels and has antibacterial effects. In vivo experiments show that the HA‐LA granular gel eliminates excessive ROS at the wound site and up‐regulates the secretion of reparative growth factors, thus, accelerating common and diabetic wound healing significantly. Therefore, the ROS‐scavenging granular gel that can be applied to the wound surface with chronic inflammation demonstrates strong clinical utility.
Combining Shell and GBT‐based Finite Elements – the Best of Both Worlds?
Authors: Manta David , Gonçalves Rodrigo , Camotim Dinar
Published: September 2022

A general and efficient approach to model thin‐walled members and frames with complex geometries (including tapered and perforated members) is proposed, combining standard shell and GBT‐based (beam) finite elements. Each element type is employed where it is most effective: (i) shell elements in plastic and geometrically complex zones, and (ii) GBT elements in prismatic and elastic zones. After providing a brief overview of the finite elements employed, several illustrative numerical examples are presented and discussed, in order to show the capabilities and potential of the proposed approach – they concern linear static, bifurcation (linear stability – calculation of buckling loadings and mode shapes), vibration (calculation of natural frequencies and vibration mode shapes), dynamic and first‐order plastic zone analyses. These numerical examples involve members with tapered segments and/or perforations and frames with complex joint geometries. For validation and comparison purposes, full shell finite element results are provided – in all cases, an excellent match is obtained.
Simplified Numerical Model Development of Lightweight‐concrete Encased Cold‐formed Steel Column‐end Joints and Panels
Authors: Eid Nathalie , Joó Attila László
Published: September 2022

With the increasing demand for using cost‐effective structures in the construction field, more and more novel structural systems have been developed. One of these new efficient systems is cold‐formed steel (CFS) members encased in polystyrene aggregate concrete (PAC). In this study, a simplified numerical model has been proposed, using ANSYS software, for PAC‐encased CFS column‐end joints and panels under compression. Each model has been validated with previous experimental results from the literature, where both ultimate axial load and failure mode were compared with tests. The main idea in this numerical model was to substitute the bracing effect of concrete on buckling with springs. A detailed imperfection sensitivity study was performed for column‐end connections to determine the effect of imperfection values on both ultimate capacities and failure modes. The necessary equivalent geometric imperfection amplitude was determined for each case of the available tests. Finally, an equivalent geometric imperfection amplitude was proposed for column‐end joints and panels to predict the design capacity according to the test failure mode.
Ductility and Buckling Behaviour of Point‐by‐Point Wire Arc Additively Manufactured Steel Bars
Authors: Silvestru Vlad‐Alexandru , Ariza Inés , Taras Andreas
Published: September 2022

The wire arc additive manufacturing (WAAM) technology in combination with computational design shows a big potential for realising novel force‐flow optimised and material‐efficient connections. This contribution deals with point‐by‐point WAAM, a material deposition strategy that allows to place material precisely where structurally needed or aesthetically desired. This could be applied, among others, for realising a novel optimised type of steel nodes between custom‐oriented profiles, as they occur in freeform steel‐glass grid‐shells. In this paper, the structural behaviour of robotically fabricated straight WAAM steel bars under uniaxial tensile and compressive loading is discussed. The focus is set on the ductility exhibited by such components as well as on the buckling behaviour observed under compressive loading. Experimental tests were conducted, both under tensile and under compressive loading to assess the influence of the irregular geometry on the structural performance. Furthermore, it was studied to what extent a prediction of the ductile structural behaviour, of the compressive load‐bearing capacity and of the post‐buckling behaviour is possible by finite element simulations. This contribution presents and discusses highlights of the obtained results.
Assessment of Design Approaches for Stainless‐Steel Joints Through an Equivalent FE Modelling Technique
Authors: Sarfarazi Sina , Shamass Rabee , Della Corte Gaetano , Guarracino Federico
Published: September 2022

Considering the significant strain‐hardening and ductility characteristics of stainless steel and the influential role of beam to column joints in the overall response of structures, a clear understanding of their moment rotation behaviour appears fundamental. In the present study, a review of the European design code for three typical semi‐continuous beam‐to‐column joints (extended end plate, flush end plate and top‐and‐seat angle connections) is first carried out. Then, using a hybrid modelling strategy with uncoupled elastic‐plastic springs for the bolts and shell elements for the members, more refined 3D finite element (FE) models are developed and validated against available test results. An equivalent stress definition is then proposed for calculating the joint moment resistance. Finally, the initial rotational stiffness, moment resistance, rotation capacity, and failure patterns are used to evaluate critically the accuracy of the predictions of the European design code. As a result, the need for more comprehensive design guidance in accordance with the observed findings is pointed out.
A Novel Residual Stress Model for Welded I‐sections and the Influence on the Stability Behaviour
Authors: Schaper Lukas , Tankova Trayana , Knobloch Markus , da Silva Luís Simões
Published: September 2022

Residual stresses have a marked influence on the stability behavior of steel members. Previous studies have shown that the structural behavior depends on both the distribution and the size of residual stresses. The residual stress distribution is affected by the cross‐section geometry, the steel grade and the manufacturing process, e.g. flame cutting and the welding procedure. A realistic consideration of residual stresses is necessary for economic models for design purposes and a safe design of steel structures.

This paper presents an experimental and numerical study on the influence of residual stresses on the stability behavior of structural members, i.e. steel columns and beams. A novel residual stress model for welded I‐shaped sections was developed and evaluated using test data. This model takes into account the main influencing parameters, i.e. the cross‐sections geometry, the steel grade as well as manufacturing process with thermal cuts or non‐thermal cuts of the steel plates. The novel residual stress model is then used to investigate the structural stability behavior in terms of a numerical simulation study. The result of the study allows to propose an improvement of the buckling curve selection for welded high strength steel columns and beams.
Influence of Welded Joints Modelling on the Structural Response of Steel Frames under Fire Situation
Authors: Segura Guillermo , Arrayago Itsaso , Mirambell Enrique
Published: September 2022

Steel frames with compact cross‐sections usually fail describing a plastic failure mechanism, redistributing internal forces. In order to fully form a plastic failure mechanism, the designed joints must be able to withstand the increase in stresses resulting from the redistribution of internal forces and to provide enough stiffness to prevent large second order effects. According to current European codes, full‐strength joints can be modelled as perfectly rigid joints and for structures with Class 1 cross‐sections carrying out a plastic analysis is allowed. Both of these statements have been widely studied at room temperature but whether these assumptions are valid under fire situation needs to be assessed yet.

With this goal in mind, this paper presents a numerical study comparing the response of steel frames for which the welded joints between members are accurately modelled with the results for frames with perfectly rigid joints, both at room temperature and at elevated temperatures. The obtained results show that modelling full‐strength joints as perfectly rigid joints for numerical purposes can also be done under fire situation without major differences in the structural response. Moreover, all the analysed Class 1 frames could form a fully plastic mechanism under fire situation.
Design of Steel Columns in Fire using Second‐order Inelastic Analysis with Strain Limits
Authors: Murtaza Hasan , Kucukler Merih
Published: September 2022

In this paper, a structural steel fire design approach using second‐order inelastic analysis with strain limits is proposed and applied to the design of steel columns in fire. The proposed design approach employs beam finite elements to conduct a second‐order inelastic analysis. Within the proposed method, strain limits are used to account for the effects of local buckling; while global instability, the loss of strength and stiffness and thermal effects are fully considered through second‐order inelastic analysis carried out using beam finite elements. The proposed method is assessed against validated shell FE results. It is observed that the proposed design approach provides consistently accurate and safe capacity predictions for steel columns in fire.
Stainless Steel Portal Frame Tests
Authors: Jůza Jan , Jandera Michal
Published: September 2022

Experiments on stainless steel frames were carried out within this research. In total, 5 portal frames made of austenitic stainless steel SHS/RHS were tested. The paper thoroughly describes the performance of the loading tests including the layout of auxiliary elements and measuring devices. The technical drawing of the experiment layout with a description is presented as well as several photos. The load‐bearing capacities of the frames are summarised in a table. The research aims for a global structure behaviour examination with a particular focus on stainless steel structures. Their behaviour is highly influenced by nonlinear material stress‐strain response. Material nonlinearity leads to loss of stiffness, which results in greater deflections. And greater deflections generate greater second‐order effects. Worldwide research show this particularity needs to be taken into consideration when conducting a global analysis of the structure.
Numerical Study on the Buckling Resistance of High Strength Steel Columns and Beam‐columns
Authors: Filho José Osvaldo Ferreira , Tankova Trayana , Carvalho Hermes , Rodrigues Filipe , da Silva Luís Simões
Published: September 2022

The rising interest in the use of high strength steel (HSS) materials is justified by several advantages that they provide. In the field of construction, their benefits range from streamlined and elegant structures to lower CO2 emissions and energy consumption. High‐rise buildings and large span bridges can be designed with smaller foundations and less structural weight, since the application of HSS makes the design with slender steel sections possible. However, special attention should be given to the stability of the compressive members since the buckling resistance generally governs their design. The existing codes to evaluate the capacity of HSS columns and beam‐columns are based on rules from experimental tests related to normal strength steel (NSS) materials, which is responsible for inconsistencies. Therefore, this current work aims to present a numerical model created and validated to evaluate the major‐ and minor‐axis flexural buckling of HSS welded I‐section columns and the combined flexural and lateral‐torsional buckling of HSS welded I‐section beam‐columns. In the following, a parametric study is also conducted, in which different cross‐sections, normalized slenderness, steel grades (from S460 up), bending moment distributions and application of restraints are considered. Finally, a comparison between the European design rules and the resistances from the Finite Element model is led, evidencing the underrating expressed by the code with a level of safety even higher when superior steel grades are evaluated.
Investigation on Shear Buckling of Corrugated Web Beams with Reinforced Web Openings
Authors: Wang Jian , Li Zheng , Robra Jörgen , Pasternak Hartmut , Euler Mathias
Published: September 2022

Corrugated web beams are welded I‐sections with thin‐walled sinusoidal corrugated webs and flanges made of wide flat steel that have been developed as an alternative to steel girders with flat webs. In comparison with hot‐rolled or welded I‐beams with flat webs, corrugated web beams are connected with considerable material savings and fully automated production. Assuming the same load‐bearing capacity, corrugated web beams are lighter than those with a flat web, since the corrugated web beams can often be loaded up to their plastic resistance without reinforcement of the web. The research on the load‐bearing behavior of corrugated web beams without web openings is relatively mature. However, the resistance of corrugated web beams with reinforced web openings, as they are often used in buildings for installations, has not well experimentally been investigated, yet. This paper deals with the shear resistance of corrugated web beams with reinforced square web openings. Three specimens of different geometry with two square web openings were tested. The experiments are compared with a Finite Element Analysis by Abaqus® and with an analytical model allowing simplified calculation. Both models can relatively accurately calculate the shear resistance. The experimental and numerical results show that the increase of the shear resistance of perforated corrugated web beams depends on the wall‐thickness and the steel grade of the web opening reinforcement.
Component Test, Fracture Simulation and Experimental Study on Steel and Shear Panel for Seismic Resistance
Authors: Gashi Ferit , Bontempi Franco , Petrini Francesco
Published: September 2022

This paper summarizes the experimental campaign carried out for the development of a new steel energy dissipative devices named Slit Dampers (SDs) designed for earthquake protection of structures. SDs consist in shear steel plates with appropriately shaped cut‐out portions of material for allowing maximum spread of plastic deformation along the device and then maximizing the hysteretic dissipative behavior. A total of eighty‐two steel shear plates with different openings and thicknesses are tested to investigate their behavior under cyclic pseudo‐static loading. Six types steel shear plates are studied, including the SD with narrow slits that divide the plate into rectangular links, and the butterfly fuse with a diamond‐shaped opening that create butterfly shape links in the plate. Other varying test parameters are: loading rate, material strength, and the number of in‐parallel damper elements. It is expected that the proposed model can be successfully used to predict the behavior of dampers in real‐world applications.
Seismic Fragility Curves of Steel Frames Equipped with Easily Repairable Dissipative Devices
Authors: Giuliani Giulia , Andreotti Roberto , Tondini Nicola , Bursi Oreste S.
Published: September 2022

This paper provides insight into a probabilistic demand analysis of a steel‐concrete structures equipped with novel dissipative components. DISSIPABLE components were studied in the framework of a European Research Fund for Coal and Steel (RFCS) project, funded to test large‐scale structures in which the dissipation is concentrated in specifically designed elements that act like a fuse and can easily be replaced after a seismic event. Incremental Dynamic Analyses (IDAs) were performed to investigate the influence of equipping steel frames with two different dissipative seismic devices, namely the Dissipative Replaceable Beam Splice (DRBeS) and the Dissipative Replaceable Link Frame (DRLF). The benchmark models were calibrated on the results of laboratory full‐scale tests, carried out in the project framework. In addition, the DISSIPABLE frame behaviour was compared with a state‐of‐the‐art moment‐resisting frame, designed according to the capacity design philosophy. Probabilistic demand models were developed, and seismic fragility curves were then derived to compare the behaviour of the analysed structural systems.
Numerical Analysis for Push‐Out Test with Y Type Perfobond Shear Connectors
Authors: Mefleh Wajdi , Kovács Nauzika
Published: September 2022

This paper focuses on the Y type perfobond shear connectors of steel‐concrete composite beams with the aim to investigate the influence of the structural parameter of the connection to the resistance and ductility of the structures. The Y shaped shear connections are a new shape developed with the benefits of resisting a higher shear force by the transversal bars and a bigger area of the concrete dowels surrounded by the Y shaped plate. This type of shear connection has significant resistance against vertical separation. In this paper, an advanced finite element model for a push‐out test with a Y type perfobond shear connector has been developed and validated by the experimental test. The aim of this research is to investigate different parameters such as the concrete strength, perfobond yield stress, the existence of the transversal bars on the structural behavior. The results showed that the concrete strength has a major effect as using a higher concrete resistance gave a higher ultimate resistance with a higher ductility. The existence of the transverse bars shows a major effect on the ductility load level. On the contrary, the effect of changing the diameter of the bars on the ductility load level was slightly noticeable. While using deferent steel grades for the perfobond plate significantly affected the ultimate resistance, but not the ductility load level. In further studies more parameters will be checked, and a formula and a guideline could be developed for a design purpose.
Parametric Finite Element Analyses of Lightweight Cold‐formed Steel‐concrete Composite Floor Beams
Authors: Lukačević Ivan , Ćurković Ivan , Rajić Andrea , Žuvelek Vlaho
Published: September 2022

Composite structural systems have many benefits, such as a high degree of prefabrication, reusability and long span capability. The main advantage of such systems is manifested through the optimal utilisation of structural steel and concrete. Additionally, allowing for demountability and reusability, the system can also result in a much smaller carbon footprint at the end of life. These advantages are particularly emphasised with the implementation of cold‐formed steel sections. This paper presents an innovative solution for a composite floor structure system consisting of built‐up cold‐formed profiles and concrete slabs made with profiled sheets. The influence of the corrugated web thickness, type of connection between steel beam elements, the degree of shear connection and steel beam height on the overall behaviour of the composite system is analysed. The performed FE analyses showed that the influence of connections between steel beam elements and the degree of shear connection had the most significant impact on system behaviour. In contrast, the steel beam height, the corrugated web thickness and spot weld density had less influence on the analysed composite system behaviour. The obtained results provide the basis for implementing laboratory research on the proposed system.
New Consistent Set of Design Equations for Equal‐leg Angle Sections and Members
Authors: Bezas Marios‐Zois , Jaspart Jean-Pierre , Vayas Ioannis , Demonceau Jean-François
Published: September 2022

Angles profiles have been used since the very beginning of the steel construction due to their easy production, transportation, and ability to be connected. However, they exhibit some specific features that clearly distinguish them from other types of common sections, as they are monosymmetric sections with very small constants in both torsion and warping, their bending capacity and radius of gyration around the weak axis are substantially lower compared to the strong axis ones, their legs are possibly susceptible to local buckling, their plastic resistances are significantly higher than their elastic ones and finally, due to the eccentric connection in one leg, they are also subjected to bending when used as single members.

The above‐listed features confirm that existing common design rules for other mostly doubly symmetric type of sections cannot safely cover angle sections, what inevitably leads to the need for development of specific design provisions for angles. Therefore, extensive experimental, analytical, and numerical studies have been conducted to propose a complete and duly validated set of design rules covering all aspects of their design (classification, cross‐section and member resistance). The proposed rules will be included in the forthcoming version of EN1993‐3.
GBT‐based Stability Analysis of Thin‐walled Members with Circular Axis
Authors: Peres Nuno , Gonçalves Rodrigo , Camotim Dinar
Published: September 2022

This paper presents a newly developed extension of the linear Generalised Beam Theory (GBT) formulation for members with circular axis, previously developed by the authors, to the linear stability analysis case. This extension incorporates the classic GBT kinematic assumptions, which ensure efficiency without sacrificing its accuracy. The finite element implementation of the proposed formulation makes it possible to calculate bifurcation loads and associated buckling mode shapes of members with circular axis and arbitrary flat‐walled cross‐sections, undergoing global‐distortional‐local deformation, with great accuracy and computational savings (with respect to refined shell finite element models). Moreover, it is shown that the remarkable GBT modal decomposition features, stemming from the fact that the kinematic description of the beam is based on a superposition of structurally meaningful cross‐section deformation modes, enable an in‐depth insight into the nature of the buckling modes in curved members.