bluuebunny/crossref_metadata_2025 huggingface dataset:
Safety Assessment for Capacity Design of Bolted Steel Connections in Tension
Authors: Snijder Hubertus H. , Knipping Jitske B.N. , Maljaars Johan , Teeuwen Paul A.
Published: September 2022

Capacity design for bolted connections in tension means that yielding of the gross cross‐section is decisive over the ultimate resistance of the net cross‐section. If the requirement for capacity design is met, ductile connection behavior is achieved, and brittle failure is avoided. However, in many practical cases the bolt holes are too large to satisfy the current capacity design requirement of EN 1993‐1‐1. In this capacity design requirement, both failure criteria involved, plastic resistance of the gross cross‐section and ultimate resistance of the net cross‐section, are considered independently with their own partial factors. This may be overly conservative. The goal of the research is to determine an improved capacity design requirement such that bigger bolt holes can be allowed without hampering safety. Both partial factors and the factor 0,9 in the net cross‐section resistance are combined in one factor. With the use of a Monte Carlo simulation a new capacity design requirement with its own combined factor is developed. Several distributions for dimensions and steel properties are used as input for the Monte Carlo simulation. The correlation between the yield stress and the ultimate strength is considered as well. In the Monte Carlo simulation, also a model factor is used. The current combined factor for the capacity design requirement is 1.39. Based on the research performed, it can be concluded that this is very conservative and that the value of the combined factor can be lowered to 1.05.
Structural Response and Design of Austenitic Stainless Steel I‐section Beam‐columns Undergoing Flexural‐Torsional Buckling
Authors: Kucukler Merih , Gardner Leroy
Published: September 2022

In this paper, the flexural‐torsional buckling response of austenitic stainless steel I‐section beam‐columns is investigated. Finite element simulations are performed with the aim of analysing the parameters affecting the behaviour of the studied members. The accuracy and safety of the existing design provisions of the European structural stainless steel design standard EN 1993‐1‐4 (2015) are assessed. A new method providing more accurate ultimate resistance predictions for austenitic stainless steel I‐section beam‐columns undergoing flexural‐torsional buckling is put forward. The higher accuracy, safety and reliability of the proposed design rules relative to EN 1993‐1‐4 (2015) are demonstrated and the new proposals have now been included in the revised Eurocode – prEN 1993‐1‐4 (2021).
Design Buckling Resistance of High Strength Steel Members
Authors: da Silva Luís Simões , Tankova Trayana , Rodrigues Filipe
Published: September 2022

EN 1993‐1‐1 gives stability design rules for columns, beams and beam‐columns up to S460, whereas EN 1993‐1‐12 gives additional guidance for S500 up to S700 (based mainly on numerical work available at the time). Recent studies on flexural buckling of welded H, I and box columns in steel grades S460 to S960, even though limited, show that improved curves can be used for members in high strength steel (HSS). The research project RUOSTE also reported improved buckling curves for HSS box and tubular sections compared to those in Table 6.2 of EN 1993‐1‐1. This improved behaviour is usually attributed due to the improved material properties but mainly due to the more favourable residual stress distribution.

Recently, within the European Project STROBE evaluation of the European stability design rules was carried out covering columns, beams, and beam‐columns. The research was based on experimental programme covering 20 full‐scale tests, residual stress measurements, advanced numerical models, analytical derivations, and statistical evaluation. Finally, it was possible to provide new, more relaxed recommendations for the buckling curve selection for HSS members.

This paper provides a summary of the project conclusions regarding the stability design of steel members in high strength steel, where firstly a brief overview of the experimental results is presented, followed by the numerical parametric study, results evaluation, and discussion.
Calibrated Design Model for the Compression Capacity of Angle Members with Welded Joints Including Accurate Joint Stiffness
Authors: Unterweger Harald , Kettler Markus , Zauchner Paul
Published: September 2022

Due to the commonly eccentric connection on only one angle leg (bolted or welded), additional bending moments are acting on the member, leading to a complex load carrying behavior with flexural and/or lateral torsional buckling phenomena. Furthermore, type and size of rotational restraints at the member's ends (provided by the adjacent structure) significantly influence the compression member capacity of these members.

Within this paper, a recently developed design model for angle members in compression is introduced. The presented method allows for calculating the internal forces based on elastic second order theory for an individual member with eccentricities and rotational spring stiffness at both ends. This calculation can be carried out by means of conventional structural analysis software. Detailed analytical equations for the estimation of appropriate spring stiffness values for several practical applications in buildings with two‐bolt connections have recently been presented by the authors. This relationship is now enhanced by means of additional formulae for angle members welded to the adjacent structure. Detailed background information on the derivation of these newly developed spring stiffness formulae is given. Finally, the accuracy of the design model for this enlarged range of application for welded angle members is shown through comparison with sophisticated finite element calculations, code provisions and experimental tests from literature.
Influence of the Shape of Initial Imperfections on Single Web and Flange Steel Plates at Elevated Temperatures
Authors: Possidente Luca , Tondini Nicola
Published: September 2022

In the last decades the buckling of steel members in fire has attracted the attention of the scientific community, but considerations about the choice of the initial imperfections have been rarely the focus of scientific publications. However, initial imperfections play a primary role in the definition of the resistance, especially when local buckling is investigated. Although the lowest buckling mode is usually employed, the definition of an appropriate imperfection shape providing, for instance, the lowest resistance is not straightforward. Even more so when the local behaviour at elevated temperatures is being studied, since the buckling behaviour may differ from the one at ambient temperature, owing to the steel degradation and possible load redistributions. In this paper steel plates in compression at elevated temperatures are studied considering different shapes of imperfection. A parametric analysis on webs and flanges composing Class 4 HE and IPE sections with S355 steel grade is presented, considering five temperatures in a relevant range (400–800°C) and several plate aspect ratios. The influence of the imperfection shapes on the resistance depending on the temperature, the length and the slenderness of the web and flange plates is discussed.
Numerical Investigation on the Thermal Behaviour of Steel‐reinforced CFST Columns in Fire
Authors: Medall David , Espinós Ana , Albero Vicente , Ibáñez Carmen , Romero Manuel L.
Published: September 2022

In previous research, the authors highlighted the limited fire resistance of slender concrete‐filled steel tubular (CFST) columns. A possible solution for enhancing the fire resistance of such columns consists of embedding an open steel profile within the concrete infill of the CFST section, generating the so‐called steel‐reinforced concrete‐filled steel tubular (SR‐CFST) section, where the inner steel profile results thermally protected by the surrounding concrete, thus delaying its degradation at elevated temperatures. This strategy may result beneficial in the fire situation as compared to other sectional configurations where the steel parts are directly exposed to the heat source.

In this paper, a two‐dimensional finite element model will be developed for studying the thermal behaviour of SR‐CFST columns and validated by comparing the temperature distribution results with experimental tests available in the literature. The numerical model will be subsequently used to carry out parametric studies, in order to analyse the influence of the different parameters, such as the cross‐section shape, outer tube thickness or the inner steel profile sectional dimensions over the thermal response of these composite sections when subjected to fire.

Finally, a simplified temperature distribution proposal will be developed, which may help practitioners for a fast evaluation of the cross‐sectional temperature field of SR‐CFST columns at a given fire resistance period by assigning an equivalent temperature to each component of the composite section (hollow steel tube, concrete encasement and inner steel profile). This simplified temperature proposal may result helpful when evaluating the sectional capacity of SR‐CFST columns in fire, by using a single strength and stiffness value for each component of the composite cross‐section corresponding to its temperature.
Design Procedure for Stainless Steel Slender I Section Members in Bending
Authors: Šorf Marek , Jandera Michal
Published: September 2022

Stainless steel welded I sections are used in structures not as often as cold‐rolled hollow sections or laser‐welded sections. But the design rules for both local buckling of very slender sections as well as lateral torsional buckling reduction factors are based on a very limited experimental and numerical research. For this reason, a new research covering these phenomena was carried out at the Czech Technical University in Prague. The contribution shows a numerical parametric study of welded slender stainless steel I‐section beams as a follow‐up of previous experimental program. The numerical study based on a validated FE model was carried out to develop a procedure for LTB of I section beams. The proposal follows the procedure of Taras, which is part of prEN 1993‐1‐1:2019, where modified constants are proposed. It was also found, that the local buckling reduction factor used in EN 1993‐1‐4:2006 may be unsafe for ordinary welded sections. The procedure in the Eurocode was developed mainly for SHS/RHS and laser‐welded sections. These fabrication methods result in significantly lower geometrical imperfections and slightly lower residual stresses than common welding methods (e.g. MIG). Therefore, a safe procedure proposal for Class 4 welded section resistance was also provided, despite not being the focus of the paper.
Applicable Equivalent Bow Imperfections in GMNIA for Eurocode Buckling Curves – in Case of Box Sections
Authors: Somodi Balázs , Bärnkopf Erzsébet , Kövesdi Balázs
Published: September 2022

The flexural buckling resistance of compressed columns is typically determined using the flexural buckling curves of EN1993‐1‐1. With advances in computing capabilities, it has become possible to obtain the flexural buckling resistance as a result of a geometrically and materially nonlinear analysis (GMNIA) using imperfections. In design practice, equivalent geometric imperfections are usually used, but their values are calibrated against GNIA analysis. In the present research work, welded box‐section columns are investigated and a proposal for relative slenderness and yield strength dependent equivalent geometric imperfection magnitudes is developed. The required equivalent bow imperfection magnitude is determined to achieve the same resistance level as the calculation according to Eurocode‐based buckling curves. GMNIA analysis are conducted on simply supported columns subjected to concentrated force. The steel grade varied between S235 and S960. Several different section geometries are studied, the relative slenderness ratio is varied between 0.3 and 2.2. Design curve is fitted to the results and recommendation is given for applicable equivalent geometric imperfection magnitudes for steel welded box‐section columns.
Assessment of Stainless Steel Tubular T‐joints Under Chord Sidewall Failure Mode by a Semi‐analytical Formulation
Authors: Nogueira Mateus M. , de Lima Luciano R. O. , da S. Vellasco Pedro C. G. , Young Ben
Published: September 2022

There are numerous benefits of tubular profiles that make them increasingly used in civil engineering. At the same time, stainless steel is a material with excellent properties and high corrosion resistance. However, stainless steel's high initial material cost has limited its use primarily to specialist and prestige applications, which makes it necessary to develop more accurate design rules for this material. When tubular profiles are used, it is necessary to assess the joint strengths, considering that they can fail by different mechanisms. The present work aims to develop a semi‐analytical formulation to predict stainless steel tubular T‐joint resistances. Joints with the brace‐to‐chord width ratio equal to 1 were considered in this study; therefore, the failure occurs in the chord sidewall. To assess the sidewall instability critical load, the exact stress fields were determined using Mathieu's theory, and then the Ritz energy method was applied. Considering that the joints are made of stainless steel, the next step is to transform the load found from linear to the non‐linear regime. For that, a new formulation based on Ramberg‐Osgood equations was developed. Finally, the results obtained from the proposed method were compared with the experimental results obtained by Feng and Young (2008) and the results from the main current standards and literature. It was observed that the proposed method presented satisfactory results, while the predictions from design codes were, in general, very conservative.
Buckling Check with Consideration of an Eccentric Load Introduction during Launching
Authors: Maier Nadine , Mensinger Martin , Ndogmo Joseph
Published: September 2022

In general, two types of launching bearings are used for launching: sliding rockers and systems with hydraulic bearings. During incremental launching, the centre of the webs of the superstructure is not perfectly in line with the centre of the launching bearings due to unavoidable tolerances. These eccentricities are not considered in the current design against plate buckling according to EN 1993‐1‐5 [2]. Furthermore, there is a significant difference between the different types of launching bearings due to their boundary conditions. At the Technical University of Munich, large‐scale buckling tests of longitudinally stiffened plates under biaxial stresses with different types of launching bearings and eccentric load introduction were carried out. The results from the validated numerical model and parameter study of the influence due to different types of launching bearings on the buckling behaviour are shown. The results are compared with the buckling verification according to the reduced stress method proposed in EN 1993‐1‐5:2019 [2]. A proposal is given that makes it possible to consider an eccentric load in the buckling verification while keeping the economical aspects in mind.
Slenderness‐dependent Equivalent Imperfections in Plate Buckling
Authors: Schönfeld Larissa , Naujoks Bernd , Ludwig Christian
Published: September 2022

In this study, various approaches to and combinations of imperfections are investigated using geometrically and materially non‐linear analysis with imperfections (GMNIA) of unstiffened buckling plates. These imperfections have a decisive influence on load‐bearing behaviour during stability failure (plate buckling). When applying GMNIA, the user can opt for either equivalent geometric imperfections or a combination of geometrical and structural imperfections as given in EN 1993‐1‐5 Annex C. Here, the exact influence of the individual imperfections and their combinations on the load‐bearing behaviour is not conclusively clarified. Furthermore, EN 1993‐1‐5 Annex C does not contain a recommendation for a suitable residual stress model. The aim of this investigation is to compare the ultimate load due to compressive stress using different approaches to imperfections. Six different combinations are analysed using GMNIA. The results make it clear that a variety of ultimate loads lie above the Winter curve for larger related slenderness values, ̄λp, and thus lead to non‐conservative ultimate loads. In addition, initial recommendations for the required size of the imperfection are given for the application of equivalent geometric imperfections depending upon the related slenderness, ̄λp. Applying adjusted equivalent geometric imperfections to square plates under compressive stress achieves very good agreement with the Winter curve in the range relevant to the construction industry.
The Curvature – Energy Relations in Buckling Analysis of Tubular Wind Turbine Towers
Authors: Ma Yang , Martinez‐Vazquez Pedro , Baniotopoulos Charalampos
Published: September 2022

A former study on wind turbine tower collapse incidences throughout the past 40 years revealed that among the various types the buckling failure was the most catastrophic as led to collapse of tubular tower shell structures. As the modern harvesting of wind energy is usually performed by wind turbine towers being cylindrical shells of thin walls, the need of thorough investigation of the buckling behaviour of shell structures operating under extreme environmental actions is obvious. The present paper addresses such knowledge gap through the study of a series of 100 numerical models underpinned by the well‐established Riks Method for buckling analysis. The method enables the scrutiny of tower shell elements under axial load and bending moment. Within the proposed framework of curvature–energy analysis, the energy stored within an imperfect shell structure is expressed and quantified through cross‐section diaphragms and symbolic lines, covering pre‐buckling, transient stage, and post‐buckling performance close to the bifurcation point. The analysis unveils changes of local surface curvature and energy flows with multiple longitudinal and circumferential wavenumbers taking place during the pre‐buckling process. Wavenumbers and curvature changes induce the energy magnitude jumping over to the adjacent buckling eigenmodes. Furthermore, the mode jumping sees a faster and more convergence result with higher bending moments. The diversity of the final buckling mode largely determined by the variance of shell geometry, compression–bending ratio and boundary conditions.
Experimental Investigation of Steel Frames Equipped with Dissipative Replaceable Links
Authors: Giuliani Giulia , Andreotti Roberto , Tondini Nicola , Bonelli Alessio
Published: September 2022

In the last decades, high priority has been given to community disaster resilience owing to seismic events with a particular focus on the post‐disaster restoration. Therefore, damage reduction of structural and non‐structural elements after a disaster is fundamental for costs and for functionality aspects. In this context, the European RFCS project DISSIPABLE was funded with the aim to perform large demonstration tests of steel frames equipped with easily repairable seismic dissipative devices. In this paper, the experimental tests performed according to dynamic substructuring are described. The capacity of withstanding seismic actions as well as the energy dissipation relies on the Dissipative Replaceable Link Frame system, composed of two rigid columns connected by weakened beams. Two different configurations of frames equipped with DRLF systems were tested: i) frames made of only mild steel and ii) frames made of both mild and high‐strength steel. Bidimensional frames were tested under different seismic intensity levels: Damage Limitation, Significant Damage and Near Collapse.
Vibration Analysis and Human Comfort Assessment of Building Subjected to Wind Dynamic Loads
Authors: de Deus Leandro de Andrade , de Souza Bastos Leonardo , Santos da Silva José Guilherme
Published: September 2022

In the last few decades, Brazilian cities have presented a substantial increasing associated to the design and construction of tall and slender buildings. However, this architectural trend has produced flexible structural systems, with low natural frequency values and, therefore, more susceptible to excessive vibrations problems, when subjected to the nondeterministic wind loadings. Having these ideas in mind, this research work aims to study the dynamic structural response and evaluate the human comfort of a 40‐storey reinforced concrete building with 150 m high and floor dimensions of 30 m by 60 m. In this research work the Spectral Representation Method (SRM) was adopted to generate the wind nondeterministic dynamic loadings, based on the use of pressure coefficients calculated through the use of different strategies such as the HFPI‐TPU and DEDM‐HRP databases, CFD modelling and the Brazilian design standard NBR 6123. The numerical model developed for the reinforced concrete building dynamic analysis, adopted the usual mesh refinement techniques present in finite element method simulations and implemented in the ANSYS program. The main conclusions obtained in this work aim to alert the civil engineers to the relevant modifications associated with the dynamic response, when different strategies are used to calculate the wind pressure coefficients on the building's facade.
Numerical Investigation of Shear Connection in Cold‐formed Steel‐concrete Composite Beam
Authors: Ćurković Ivan , Lukačević Ivan , Žuvelek Vlaho , Rajić Andrea
Published: September 2022

Researches show that composite systems made by combining cold‐formed steel (CFS) elements and concrete can produce excellent properties compared to traditional solutions. One of the solution which employs CFS elements and concrete is the subject of research within the LWT‐FLOOR project. The LWT‐FLOOR system consists of built‐up CFS beams with corrugated web, connected by spot welds and concrete slab with an innovative shear connection. This paper presents a numerical investigation of two types of shear connections suitable for the proposed composite solution. One type of shear connection is completed using bolts which provide a direct shear connection between the flange profiles of the steel girder and the concrete slab. The second type of shear connection is achieved using a composite dowel rib connector realised through a steel beam corrugated web. In this case, the connection between the profiles of the steel beam and the concrete flange is realised indirectly, i.e., through spot welds between C profiles and corrugated web. The results of FE simulations indicate that a solution with bolts ensures higher shear, but reduces its ductility. These results provide the basis for the conduction of experimental push‐out tests of the proposed shear connection types.
Enabling a Ductile Failure of Laminated Glass Beams with Iron‐Based Shape Memory Alloy (Fe‐SMA) Strips
Authors: Silvestru Vlad‐Alexandru , Deng Zhikang , Michels Julien , Taras Andreas
Published: September 2022

Laminated glass beams are used as structural elements to support transparent roofs or to transfer wind loads acting on transparent facades. However, in case of breakage, laminated glass beams only exhibit a low residual load‐carrying capacity provided by the interlayers. A more efficient solution is to add a filigree ductile reinforcement on the tension side of the laminated glass beams, for instance by adhesive bonding. By these means, the post‐cracking behaviour of the beams and their redundancy can be improved and a ductile failure behaviour can be achieved. Moreover, an additional pre‐stressing of this reinforcement allows increasing the initial glass cracking resistance. Despite their obvious potential, an application of pre‐stressed laminated glass beams in real projects is prevented by the rather complicated necessary procedures for pre‐stressing. This contribution discusses first experimental results on a novel concept for pre‐stressed laminated glass beams with adhesively bonded strips made of an iron‐based shape memory alloy (Fe‐SMA). The pre‐stress can be applied in this case by heating up the Fe‐SMA. The feasibility of the concept is analysed based on results from four‐point‐bending tests on medium‐scale simple, reinforced and pre‐stressed laminated glass beams.
Technical Study of Kongo‐Central Colonial Steel Houses Belonging to the DRC Patrimony
Authors: Nkole Kabongo Aris Mpemba , Jaspart Jean‐Pierre , Demonceau Jean‐François
Published: September 2022

The built heritage is a collection of properties of heritage value that should be protected and preserved. Designed in Belgium and built in the Democratic Republic of Congo (DRC) at the beginning of colonisation, the steel‐framed houses in the province of Kongo‐Central are in an advanced state of damages due not only to the climatic conditions of the area, but also to those of exploitation. An architectural and technical study of these steel houses is nowadays required to develop solutions for their conservation as part of the DRC's built heritage. In this context, the National Fund for Scientific Research of Belgium (FNRS) is financing the research project entitled “Tropicalisation of engineering and architecture”. This project is carried out jointly by the Université libre de Bruxelles (in charge of the architectural part) and the Université de Liège (in charge of the engineering part). For this project, the courthouse of Mbanza‐Ngungu (former ABC Hotel in Thysville) is studied in detail as a case study to identify the techniques used during construction, the pathologies affecting the structures and the solution which could be contemplated for their refurbishment. The present paper will introduce first investigation conducted in the framework of this project.
Seeding rate affects the performance of oat and black oat
Authors: Santos Erick Rodrigo da Silva , Dubeux José Carlos Batista , Dantas Queiroz Luana Mayara , Jaramillo David Mirabedini , Garcia Liza , van Cleef Flavia de Oliveira Scarpino , Sousa de Abreu Daciele , Ruiz‐Moreno Martin
Published: September 2022

Basic management practices, including ideal seeding rates, are still lacking for black oat (Avena strigosa Schreb.) in the southeastern United States. This study evaluated the performance of five seeding rates (15, 30, 60, 120, and 240 lb acre−1) on ‘Legend 567’ oat (Avena sativa L.) and ‘UF‐10’ black oat at three harvest dates (early, mid‐season, and late) per year. Seeding rates of 60, 120, and 240 lb acre−1 tended (P = .07) to increase total herbage accumulation [4,760 lb dry matter (DM) acre−1] compared with 15 lb acre−1 (3,945 lb DM acre−1). Tiller density was usually greater for black oat than for oat. Seeding rate was positively associated with tiller density and explained 84 to 98% and 96 to 98% of the variation for black oat and oat, respectively. Tiller mass was greater for oat (0.045 oz tiller−1) than black oat (0.034 oz tiller−1), and greater for the mid‐season harvest (0.043 oz tiller−1), compared with the early and late harvests (0.037 oz tiller−1 on average). There was a negative effect (P < .001) of seeding rate on tiller mass. Increasing the seeding rate had a negative effect on leaf length at the early and middle harvests (P < .05), and decreased leaf width from 0.56 to 0.39 inches in oat, and from 0.32 to 0.29 inches in black oat when changing from 15 to 240 lb acre−1. To maximize herbage accumulation at a lower seeding rate, we recommend 60 lb acre−1 for both oat and black oat for multiple harvests.
Effects of Pretreatment on the Biocatalysis of Renewable Resources
Authors: Varriale Ludovica , Volkmar Marianne , Weiermüller Jens , Ulber Roland
Published: September 2022

Within a biorefinery platform several conversion steps such as pretreatment, saccharification, fermentation and downstream processing are necessary to obtain the final bio‐based product(s) from lignocellulosic biomass. The structural composition of the biomass, especially the lignin content, determines the necessary pretreatment steps. To obtain sugar monomers, the hydrolysis of lignocellulosic biomass is an essential step. This work examines the impact of different pretreatments on the sugar release during biocatalysis. Even without prior pretreatment the biocatalysis of low lignin biomass achieves glucose yields of up to 93 %, while the biocatalysis of high lignin biomass requires an upstream hydrothermal procedure to achieve a glucose yield of 74 %.
A novel robust dynamic method for NOx emissions prediction in a thermal power plant
Authors: Liu Ying , Zhou Jianxin , Fan Wei
Published: September 2022

NOx is a harmful by‐product of coal‐fired boilers, and accurate prediction of NOx emissions in the outlet of a boiler is essential for environmental protection. In recent years, data‐driven models have been widely studied and applied in this area. However, dynamic characteristics are ignored by many existing models, leading to sub‐optimal performance. Besides, outliers that occur in the operation data have adverse effects on the efficacy of these prediction models. To address these issues, this paper presents a novel method for predicting NOx concentration via integrating a robust dynamic probabilistic approach and the long short‐term memory (LSTM). First, mutual information (MI) is applied to determine the input variables. Subsequently, a robust probabilistic method is proposed to extract dynamic latent features considering outliers. On this basis, the generated latent variables are further utilized to train the LSTM‐based model, with which the intrinsic relation between inputs and NOx values are obtained. Based on the application to a 660 MW thermal power plant, the superiority of the proposed method is demonstrated in terms of high prediction accuracy.
Call for a holistic framework for cancer immunotherapy
Authors: Boesch Maximilian , Baty Florent , Kowatsch Tobias , Wolf Dominik , Früh Martin , Brutsche Martin H.
Published: September 2022

Cancer immunotherapy outcomes are shaped by various soft variables including diet/microbiome, physical activity, and circadian rhythms. This commentary advocates a holistic framework for cancer immunotherapy to enhance treatment response and improve quality of life.
Visible‐Light‐Driven Lignin Valorization into Value‐Added Chemicals and Sustainable Hydrogen Using Zn1‐xCdxS Solid Solutions as Photocatalyst
Authors: Palma Bruna , Cheng Xi , Liu Liyang , Zhong Na , Zhao Heng , Renneckar Scott , Larter Stephen , Kibria Md Golam , Hu Jinguang
Published: September 2022

Biomass photorefinery for simultaneous production of value‐added chemicals and sustainable hydrogen holds promising perspective to achieve a negative carbon economy. However, insight into lignin valorization by the photorefinery approach is still lacking due to the extremely complex structure and component. In this work, we design a series of Zn1‐xCdxS solid solutions as photocatalyst to reveal the photocatalytic mechanism for model component conversion. Bandgap engineering by changing the Zn/Cd ratio is proven to efficiently regulate the reaction pathway. Specifically, Zn0.75Cd0.25S (ZCS25) presented the best performance for hydrogen evolution (610±105 μmol h−1 gcat.−1) while Zn0.5Cd0.5S (ZCS50) demonstrated the best substrate conversion to monophenolic compounds. Besides, the well‐designed Zn1‐xCdxS solid solutions also show the ability to produce hydrogen and eliminate a methoxy group from real lignin by the photorefinery approach. This present work demonstrates a good example of biomass valorization by careful design of photocatalysts.
Marijuana and 10‐drink binges on the increase among young adults
Authors: Knopf Alison
Published: September 2022

The Monitoring the Future (MTF) study released in August by the National Institute on Drug Abuse (NIDA) found that marijuana use has reached historic highs among young adults ages 19 to 30 years old, with 29% using marijuana in the past 30 days, and 43% using it in the past year; 10.8% used it on a daily or near daily basis (more than 20 days in the past 30 days). The study uses self‐reports; most recent data is from 2021.
Study of the Crystalline Perfection, Homogeneity, Chemical Etching on the Surface, and Third‐Order Nonlinear Optical Properties of (1 1 0) Oriented Hydroxyethylammonium D‐Tartrate Monohydrate Single Crystal and Hirshfeld Surface Analysis
Authors: Abdul Hakkim Mohamad Asikali , Paulraj Rajesh , Sidden Chinnasami , Perumalsamy Ramasamy
Published: September 2022

The single crystal of hydroxyethylammonium D‐tartrate monohydrate (HEDT) is grown along the (1 1 0) plane using the Sankaranarayanan–Ramasamy method. The powder X‐ray diffraction and the high‐resolution X‐ray diffraction analyses are used to corroborate the growth plane and perfection of the crystallinity, respectively. The birefringence experiment has proven crystalline homogeneity and estimated birefringence value (Δn) is 0.109. The surface morphology of the grown crystal is examined by chemical etching analysis and irregular hillock patterns are found. The transmittance for the (1 1 0) plane of the HEDT is inspected by a UV‐Vis analysis. The second harmonic generation efficiency of the HEDT crystal is 1.7 times that of potassium dihydrogen phosphate (KDP). The third‐order nonlinear optical (TONLO) properties of the grown HEDT crystal are scrutinized by the Z‐scan experiment. The estimated TONLO susceptibility of HEDT crystal is 6.827 × 10−8 esu. The laser damage threshold value of HEDT is discovered to be 5.24 GW cm−2. The 3D Hirshfeld surface visualizes the interaction between HEDT molecules and analyzes the distance from the surface of the molecule to the farthest and the nearest atom. The important contributions of crystal packing are explored by 2D‐fingerprint plots.
Three‐Dimensional Holey Graphene Enwrapped Li3V2(PO4)3/N‐Doped Carbon Cathode for High‐Rate and Long‐Life Li‐Ion Batteries
Authors: Li Xiaopeng , Du Xingyu , Xu Yulin , Li Jianming , Wang Yujue , Meng Yan , Xiao Dan
Published: September 2022

Monoclinic Li3V2(PO4)3 is a promising cathode material for high‐power Li‐ion batteries. Herein, a three‐dimensional holey graphene enwrapped Li3V2(PO4)3/N‐doped carbon (LVPNCHG) nanocomposite has been successfully synthesized. The holes could be in‐situ and directly introduced in graphene through H2O2 chemical etching in the synthesis process, which could remarkably enhance the ion and electron transport and greatly improve the electrochemical performance of the LVPNCHG electrode: 78 mAh g−1 at 150 C, 86.1 % capacity retention over 2000 cycles at 10 C, and 96 % capacity retention over 500 cycles at 1 C under −20 °C. Moreover, in‐situ distribution of relaxation time analysis was used to study LVPNCHG cathode during charge/discharge at 3.0–4.8 V, combined with in‐situ X‐ray diffraction measurement, and the results showed that a two‐phase reaction mechanism was involved during the insertion of Li+ in the discharge process. Further demonstration of graphite//LVPNCHG full cell indicated great potential of the as‐synthesized materials for practical application.
A randomized, double‐blind, placebo‐controlled phase 1 and phase 2 clinical trial to evaluate efficacy and safety of a SARS‐CoV‐2 vaccine SCoK in adults
Authors: Luo Deyan , Pan Hongxing , He Peng , Yang Xiaolan , Li Tao , Ning Nianzhi , Fang Xin , Yu Wenjing , Wei Mingwei , Gao Hui , Wang Xin , Gu Hongjing , Mei Maodong , Li Xinwang , Zhang Liangyan , Li Deyu , Gao Chunrun , Gao Jinbang , Fei Guoqiang , Li Ying , Yang Yuguo , Xu Yi , Wei Wenjin , Sun Yansong , Zhu Fengcai , Hu Zhongyu , Wang Hui
Published: September 2022

Background

To determine an appropriate dose of, and immunization schedule for, a vaccine SCoK against COVID‐19 for an efficacy study; herein, we conducted randomized controlled trials to assess the immunogenicity and safety of this vaccine in adults.

Methods

These randomized, double‐blind, placebo‐controlled phase 1 and 2 trials of vaccine SCoK were conducted in Binhai District, Yan City, Jiangsu Province, China. Younger and older adult participants in phase 1 and 2 trials were sequentially recruited into different groups to be intramuscularly administered 20 or 40 μg vaccine SCoK or placebo. Participants were enrolled into our phase 1 and 2 studies to receive vaccine or placebo.

Results

No serious vaccine‐related adverse events were observed in either trial. In both trials, local and systemic adverse reactions were absent or mild in most participants. In our phase 1 and 2 studies, the vaccine induced significantly increased neutralizing antibody responses to pseudovirus and live SARS‐CoV‐2. The vaccine induced significant neutralizing antibody responses to live SARS‐CoV‐2 on day 14 after the last immunization, with NT50s of 80.45 and 92.46 in participants receiving 20 and 40 μg doses, respectively; the seroconversion rates were 95.83% and 100%. The vaccine SCoK showed a similar safety and immunogenicity profiles in both younger participants and older participants. The vaccine showed better immunogenicity in phase 2 than in phase 1 clinical trial. Additionally, the incidence of adverse reactions decreased significantly in phase 2 clinical trial. The vaccine SCoK was well tolerated and immunogenic.
The combination of DNA methylome and transcriptome revealed the intergenerational inheritance on the influence of advanced maternal age
Authors: Hua Lingyue , Chen Wei , Meng Yan , Qin Meng , Yan Zhiqiang , Yang Rui , Liu Qiang , Wei Yuan , Zhao Yangyu , Yan Liying , Qiao Jie
Published: September 2022

Background

The number of women delivering at advanced maternal age (AMA; > = 35) continuously increases in developed and high‐income countries. Large cohort studies have associated AMA with increased risks of various pregnancy complications and adverse pregnancy outcomes, which raises great concerns about the adverse effect of AMA on the long‐term health of offspring. Specific acquired characteristics of parents can be passed on to descendants through certain molecular mechanisms, yet the underlying connection between AMA‐related alterations in parents and that in offspring remains largely uncharted.

Methods

We profiled the DNA methylomes of paired parental peripheral bloods and cord bloods from 20 nuclear families, including 10 AMA and 10 Young, and additional transcriptomes of 10 paired maternal peripheral bloods and cord bloods.

Results

We revealed that AMA induced aging‐like changes in DNA methylome and gene expression in both parents and offspring. The expression changes in several genes, such as SLC28A3, were highly relevant to the disorder in DNA methylation. In addition, AMA‐related differentially methylated regions (DMRs) identified in mother and offspring groups showed remarkable similarities in both genomic locations and biological functions, mainly involving neuron differentiation, metabolism, and histone modification pathways. AMA‐related differentially expressed genes (DEGs) shared by mother and offspring groups were highly enriched in the processes of immune cell activation and mitotic nuclear division. We further uncovered developmental‐dependent dynamics for the DNA methylation of intergenerationally correlated DMRs during pre‐implantation embryonic development, as well as diverse gene expression patterns during gametogenesis and early embryonic development for those common AMA‐related DEGs presenting intergenerational correlation, such as CD24. Moreover, some intergenerational DEGs, typified by HTRA3, also showed the same significant alterations in AMA MII oocyte or blastocyst.

Conclusions

Our results reveal potential intergenerational inheritance of both AMA‐related DNA methylome and transcriptome and provide new insights to understand health problems in AMA offspring.
Restoration of native saltmarshes can reverse arthropod assemblages and trophic interactions changed by a plant invasion
Authors: Jiang Jia‐Jia , Zhao Yu‐Jie , Guo Yaolin , Gao Lei , Richards Christina L. , Siemann Evan , Wu Jihua , Li Bo , Ju Rui‐Ting
Published: September 2022

Plant invasions profoundly impact both natural and managed ecosystems, and removal of the invasive plants addresses only part of the problem of restoring impacted areas. The rehabilitation of diverse communities and their ecosystem functions following removal of invasive plants is an important goal of ecological restoration. Arthropod assemblages and trophic interactions are important indicators of the success of restoration, but they have largely been overlooked in saltmarshes. We determined how arthropod assemblages and trophic interactions changed with the invasion of the exotic plant Spartina alterniflora and with the restoration of the native plant Phragmites australis following Spartina removal in a Chinese saltmarsh. We investigated multiple biotic and abiotic variables to gain insight into the factors underlying the changes in arthropod assemblages and trophic structure. We found that although Spartina invasion had changed arthropod diversity, community structure, feeding‐guild composition, and the diets of arthropod natural enemies in the saltmarsh, these changes could be reversed by the restoration of native Phragmites vegetation following removal of the invader. The variation in arthropod assemblages and trophic structure were critically associated with four biotic and abiotic variables (aboveground biomass, plant density, leaf N, and soil salinity). Our findings demonstrate the positive effects of controlling invasive plants on biodiversity and nutrient cycling and provide a foundation for assessing the efficacy of ecological restoration projects in saltmarshes.
Synthesis and Characterization of Homoleptic Rare Earth Nitrato Complexes with the Quaternary Ammonium Cations Et4N+ and nPr4N+
Authors: Tarlton Michael L. , Wilson Richard E.
Published: September 2022

Two periodic series of homoleptic rare earth nitrato complexes, [R4N]x[M(NO3)y] (M=La−Nd, Sm−Lu, Y); R=Et,
Pr; x=2‐3; y=5‐6) have been synthesized, and characterized by single crystal X‐ray diffraction, IR and Raman spectroscopy, comparing the solid state speciation of the nitrate ions as a function of lanthanide ion and quaternary ammonium cation. The series of the form [Et4N]3[Ln(NO3)6] crystallizes in the rhombohedral space group R
, as a twelve‐coordinate hexanitrato complex [Et4N]3[Ln(NO3)6] with cocrystallized HNO3 for La, Pr, and Nd. For Ce, a distinct orthorhombic phase retaining the same formula, [Et4N]3[Ce(NO3)6] is isolated in the absence of HNO3 to prevent oxidation of the Ce(III) to Ce(IV) in nitric acid. A ten‐coordinate pentanitrato complex, [Et4N]2[Ln(NO3)5], in monoclinic symmetry forms for the remainder of the series, and for Y(III). The entire series crystallized in the presence of [nPr4N]+ counterions forms a pentanitrato complex [nPr4N]2[M(NO3)5] in the orthorhombic space group, Pccn. Analysis of trends in the structural and spectroscopic characteristics of these series reveal insight into the structure‐directing influences of both the lanthanide contraction and the quaternary ammonium cations.
Base‐Promoted [3+3]‐Cycloaddition of γ‐Hydroxy‐α,β‐unsaturated Carbonyls with N,N′‐Cyclic Azomethine Imines for Synthesizing Bicyclic Oxadiazines
Authors: Kang Sung Hyun , Park Byung Jun , Kim Sung‐Gon
Published: September 2022

A novel approach of [3+3]‐cycloaddition of N,N′‐cyclic azomethine imines with γ‐hydroxy‐α,β‐unsaturated carbonyls was developed. Bicyclic oxadiazines were readily obtained in moderate to good yields from the reactions of various γ‐hydroxy‐α,β‐unsaturated ketones, including aromatic and aliphatic ketones, with N,N′‐cyclic azomethine imines under mild conditions, demonstrating the broad substrate scope.
Light‐Induced Dealkylation of Benzamides in Aqueous Solution
Authors: Cybularczyk‐Cecotka Martyna , Kamińska Agnieszka , Jopek Zuzanna , Giedyk Maciej
Published: September 2022

The N‐dealkylation reactions of benzamides occur naturally in living organisms but chemical methods remain poorly developed. So far, light‐induced variants of these processes have been restricted to amides containing secondary N‐alkyl groups or required pre‐functionalization of the starting material. Here, we present a direct, controllable N‐dealkylation of tertiary and secondary benzamides possessing primary alkyl substituents at N‐atom. The developed strategy operates in aqueous environment under mild conditions involving either blue LEDs or sunlight irradiation. Preliminary mechanistic studies indicate two‐step oxidation and the intermediacy of radicals at α‐position to N‐atom. Selectivity in N‐dealkylation of homo‐ and heterosubstituted tertiary benzamides is also investigated.
Competition between Two Modes of 6π‐Photocyclization: A Case Study for 3‐(1,2‐Diarylvinyl)‐2‐arylimidazo[1,2‐a]pyridines
Authors: Ustyuzhanin Alexander O. , Bidusenko Ivan A. , Kouame Eric Koffi , Ushakov Igor A. , Gudovannyy Alexey O. , Lyssenko Konstantin A. , Schmidt Elena Yu. , Lvov Andrey G.
Published: September 2022

The photochemical 6π‐electrocyclization of diarylethenes (DAE), 2‐vinylbiaryls (VBA) and their derivatives is widely used in organic synthesis. Combination of these motifs in one molecule opens the issue of selectivity of the photochemical reaction. We have found that upon UV irradiation, 3‐(1,2‐diarylvinyl)‐2‐arylimidazo[1,2‐a]pyridines comprising both DAE and VBA moieties form products of VBA cyclization followed by oxidation. The selectivity of the process was rationalized by DFT calculations. The presented reaction gave access to highly fluorescent 5,6‐diarylnaphtho[1′,2′:4,5]imidazo[1,2‐a]pyridine derivatives.
Synthesis and Mesophase Properties of Triphenylene Dimers Linked through Linear and Bent Alkyne‐Aryl‐Alkyne Bridges
Authors: Alsahli Ahad O. , Cammidge Andrew N.
Published: September 2022

Nematic mesophase formation in disc‐like systems remains relatively rare compared to higher‐order columnar organisation, but it is observed in some rigid dimeric systems. Mesophase formation in rigid discotic dimers has been sequentially probed and is shown to be predictably controlled through structural choice of the bridge. Moderately bent bridges shorten the discogen separation and reduce conformational freedom. Severely bent dimers (1,2‐phenylene bridge) show no mesophases but, as the angle is widened, columnar and nematic organisation becomes possible and progressively more favoured. The linear arrangement gives the most stable columnar mesophase and a narrow‐range nematic mesophase.
Two for the price of one: If moving beyond traditional single‐best discrete choice experiments, should we use best‐worst, best‐best or ranking for preference elicitation?
Authors: Huls Samare P. I. , Lancsar Emily , Donkers Bas , Ride Jemimah
Published: September 2022

This study undertook a head‐to‐head comparison of best‐worst, best‐best and ranking discrete choice experiments (DCEs) to help decide which method to use if moving beyond traditional single‐best DCEs. Respondents were randomized to one of three preference elicitation methods. Rank‐ordered (exploded) mixed logit models and respondent‐reported data were used to compare methods and first and second choices. First choices differed from second choices and preferences differed between elicitation methods, even beyond scale and scale dynamics. First choices of best‐worst had good choice consistency, scale dynamics and statistical efficiency, but this method's second choices performed worst. Ranking performed best on respondent‐reported difficulty and preference; best‐best's second choices on statistical efficiency. All three preference elicitation methods improve efficiency of data collection relative to using first choices only. However, differences in preferences between first and second choices challenge moving beyond single‐best DCE. If nevertheless doing so, best‐best and ranking are preferred over best‐worst DCE.