bluuebunny/crossref_metadata_2025 huggingface dataset:
LEGAL POLICY ON SIDE EFFECT OF THE COVID-19 VACCINE ACCORDING TO HEALTH LAW
Authors: Yusriando Yusriando , Tanjaya Willy , Ramanathan Ramanathan
Published: December 2023

Health of the Republic of Indonesia Number: 10 of 2021 concerning the Implementation of Vaccination in the Context of Combating the Corona Virus Disease 2019 (Covid19) Pandemic which refers to Law Number: 36 of 2009 concerning Health , Law Number: 4 of 1984 concerning Outbreaks of Infectious Diseases and Law Number 6 of 2018 concerning Health Quarantine. According to the regulation of the minister of health that vaccination is carried out at health facilities, however, vaccination can be carried out outside health facilities; The government's responsibility for the side effects of the covid-19 vaccine has not yet been seen in the community so that it has the impact of refusing vaccination because the most fatal side effect of the covid-19 vaccination is that it can cause death apart from concerns about the halalness of the covid-19 vaccine In addition, there is no specific rule regarding compensation as referred to in the existing regulations for people who die after being vaccinated;The legal impact if the community refuses to be vaccinated can be given sanctions based on the Regulation of the Minister of Health of the Republic of Indonesia Number: 10 of 2021 concerning the Implementation of Vaccination in the Context of Combating the 2019 Corona Virus Disease (Covid19) Pandemic which is linked to Article 14 paragraph (1) of the Republic of Indonesia Law Number: 4 1984 concerning Outbreaks of Infectious Diseases, but the narrative of the article in question is not in line with the intention of refusing vaccines so that it can lead to multiple interpretations in enforcing sanctions on people who refuse to be vaccinated.
Shared and distinct pathways and networks genetically linked to coronary artery disease between human and mouse
Authors: Kurt Zeyneb , Cheng Jenny , Barrere-Cain Rio , McQuillen Caden N , Saleem Zara , Hsu Neil , Jiang Nuoya , Pan Calvin , Franzén Oscar , Koplev Simon , Wang Susanna , Björkegren Johan , Lusis Aldons J , Blencowe Montgomery , Yang Xia
Published: December 2023

Mouse models have been used extensively to study human coronary artery disease (CAD) or atherosclerosis and to test therapeutic targets. However, whether mouse and human share similar genetic factors and pathogenic mechanisms of atherosclerosis has not been thoroughly investigated in a data-driven manner. We conducted a cross-species comparison study to better understand atherosclerosis pathogenesis between species by leveraging multiomics data. Specifically, we compared genetically driven and thus CAD-causal gene networks and pathways, by using human GWAS of CAD from the CARDIoGRAMplusC4D consortium and mouse GWAS of atherosclerosis from the Hybrid Mouse Diversity Panel (HMDP) followed by integration with functional multiomics human (STARNET and GTEx) and mouse (HMDP) databases. We found that mouse and human shared >75% of CAD causal pathways. Based on network topology, we then predicted key regulatory genes for both the shared pathways and species-specific pathways, which were further validated through the use of single cell data and the latest CAD GWAS. In sum, our results should serve as a much-needed guidance for which human CAD-causal pathways can or cannot be further evaluated for novel CAD therapies using mouse models.
Hsf1 and the molecular chaperone Hsp90 support a ‘rewiring stress response’ leading to an adaptive cell size increase in chronic stress
Authors: Maiti Samarpan , Bhattacharya Kaushik , Wider Diana , Hany Dina , Panasenko Olesya , Bernasconi Lilia , Hulo Nicolas , Picard Didier
Published: December 2023

Cells are exposed to a wide variety of internal and external stresses. Although many studies have focused on cellular responses to acute and severe stresses, little is known about how cellular systems adapt to sublethal chronic stresses. Using mammalian cells in culture, we discovered that they adapt to chronic mild stresses of up to two weeks, notably proteotoxic stresses such as heat, by increasing their size and translation, thereby scaling the amount of total protein. These adaptations render them more resilient to persistent and subsequent stresses. We demonstrate that Hsf1, well known for its role in acute stress responses, is required for the cell size increase, and that the molecular chaperone Hsp90 is essential for coupling the cell size increase to augmented translation. We term this translational reprogramming the ‘rewiring stress response’, and propose that this protective process of chronic stress adaptation contributes to the increase in size as cells get older, and that its failure promotes aging.
Opposing chemosensory functions of closely related gustatory receptors
Authors: Ahn Ji-Eun , Amrein Hubert
Published: December 2023

In the fruit fly Drosophila melanogaster, gustatory sensory neurons express taste receptors that are tuned to distinct groups of chemicals, thereby activating neural ensembles that elicit either feeding or avoidance behavior. Members of a family of ligand -gated receptor channels, the Gustatory receptors (Grs), play a central role in these behaviors. In general, closely related, evolutionarily conserved Gr proteins are co-expressed in the same type of taste neurons, tuned to chemically related compounds, and therefore triggering the same behavioral response. Here, we report that members of the Gr28 subfamily are expressed in largely non-overlapping sets of taste neurons in Drosophila larvae, detect chemicals of different valence, and trigger opposing feeding behaviors. We determined the intrinsic properties of Gr28 neurons by expressing the mammalian Vanilloid Receptor 1 (VR1), which is activated by capsaicin, a chemical to which wild-type Drosophila larvae do not respond. When VR1 is expressed in Gr28a neurons, larvae become attracted to capsaicin, consistent with reports showing that Gr28a itself encodes a receptor for nutritious RNA. In contrast, expression of VR1 in two pairs of Gr28b.c neurons triggers avoidance to capsaicin. Moreover, neuronal inactivation experiments show that the Gr28b.c neurons are necessary for avoidance of several bitter compounds. Lastly, behavioral experiments of Gr28 deficient larvae and live Ca2+ imaging studies of Gr28b.c neurons revealed that denatonium benzoate, a synthetic bitter compound that shares structural similarities with natural bitter chemicals, is a ligand for a receptor complex containing a Gr28b.c or Gr28b.a subunit. Thus, the Gr28 proteins, which have been evolutionarily conserved over 260 million years in insects, represent the first taste receptor subfamily in which specific members mediate behavior with opposite valence.
Microprism-based two-photon imaging of the mouse inferior colliculus reveals novel organizational principles of the auditory midbrain
Authors: Ibrahim Baher A. , Shinagawa Yoshitaka , Douglas Austin , Xiao Gang , Asilador Alexander R. , Llano Daniel A.
Published: December 2023

To navigate real-world listening conditions, the auditory system relies on the integration of multiple sources of information. However, to avoid inappropriate cross-talk between inputs, highly connected neural systems need to strike a balance between integration and segregation. Here, we develop a novel approach to examine how repeated neurochemical modules in the mouse inferior colliculus lateral cortex (LC) allow controlled integration of its multimodal inputs. The LC had been impossible to study via imaging because it is buried in a sulcus. Therefore we coupled two-photon microscopy with the use of a microprism to reveal the first-ever sagittal views of the LC to examine neuronal responses with respect to its neurochemical motifs under anesthetized and awake conditions. This approach revealed marked differences in the acoustic response properties of LC and neighboring nonlemniscal portions of the inferior colliculus. In addition, we observed that the module and matrix cellular motifs of the LC displayed distinct somatosensory and auditory responses. Specifically, neurons in modules demonstrated primarily offset responses to acoustic stimuli with enhancement in responses to bimodal stimuli, whereas matrix neurons showed onset response to acoustic stimuli and suppressed responses to bimodal stimulation. Thus, this new approach revealed that the repeated structural motifs of the LC permit functional integration of multimodal inputs while retaining distinct response properties.
Strategies to Improve Medical Communication
Authors: Cappola Anne R. , Cohen Karthika S.
Published: December 2023

This JAMA Insights summarizes strategies for effective medical communication, with considerations for the message delivered, the messenger source, and the social context.
Human WIPI β‐propeller function in autophagy and neurodegeneration
Authors: Proikas‐Cezanne Tassula , Haas Maximilian L. , Pastor‐Maldonado Carmen J. , Schüssele David S.
Published: December 2023

The four human WIPI β‐propellers, WIPI1 through WIPI4, belong to the ancient PROPPIN family and fulfill scaffold functions in the control of autophagy. In this context, WIPI β‐propellers function as PI3P effectors during autophagosome formation and loss of WIPI function negatively impacts autophagy and contributes to neurodegeneration. Of particular interest are mutations in WDR45, the human gene that encodes WIPI4. Sporadic WDR45 mutations are the cause of a rare human neurodegenerative disease called BPAN, hallmarked by high brain iron accumulation. Here, we discuss the current understanding of the functions of human WIPI β‐propellers and address unanswered questions with a particular focus on the role of WIPI4 in autophagy and BPAN.
Crop rotation for management of plant‐parasitic nematodes in forage corn production
Authors: Tsegay Mussie Wolday , Wallau Marcelo O. , Liu Chang , Dubeux José C. , Grabau Zane Joseph
Published: December 2023

Corn (Zea mays L.) is an important silage source for dairy cattle production in the southeastern United States. Silage corn is often grown continuously, which frequently results in severe pressure from plant‐parasitic nematodes such as sting nematode (Belonolaimus longicaudatus). Crop rotation is one of the few nematode management options available in forage production. The research objective was to assess summer‐planted rotation crops, preceding spring silage corn, for management of plant‐parasitic nematodes. Rotation crops included field corn, pearl millet [Cenchrus americanus (L.) Morrone]—with or without fertilizer—, sorghum‐sudangrass [Sorghum bicolor (L.) Moench × Sorghum sudanense Piper], and sunn hemp (Crotalaria juncea L.), which was either incorporated into soil or harvested. Rotation crops were assessed in a 3‐year field study in central Florida. Sunn hemp treatments significantly reduced sting nematode soil abundances relative to corn by 84%, 90%, and 84% before spring corn planting in 2019–2020 and 2020–2021 and at rotation crop termination in 2021–2022, respectively. Abundances of other plant‐parasitic nematodes were not consistently influenced by rotation. Biomass of winter rye (Secale cereale L.)—a bridge cover crop between summer and spring crops—was consistently increased following sunn hemp with significant increases of 87%, 106%, and 186% relative to following corn in 2019–2020, 2020–2021, and 2021–2022, respectively. Similarly, sunn hemp significantly increased spring corn yield by 70% and 136% relative to double‐cropped corn in 2020–2021 and 2021–2022, respectively. Overall, rotation with sunn hemp improved plant‐parasitic nematode management in forage corn production relative to rotations with only gramineous crops.
Statin use moderates APOE's and CRP's associations with dementia and is associated with lesser dementia severity in ε4 carriers
Authors: Royall Donald R. , Palmer Raymond F. ,   for the Alzheimer's Disease Neuroimaging Initiative (ADNI)
Published: December 2023

INTRODUCTION

We tested the effect of statins on C‐reactive protein (CRP) and apolipoprotein E (APOE)'s associations with dementia severity.

METHODS

A total of 1725 participants of the Alzheimer's Disease Neuroimaging Initiative (ADNI) were assigned from 12‐month follow‐up data into the following groups: (1) ε4 (–)/statin (–), (2) ε4 (–)/statin (+), (3) ε4 (+)/statin (–), and (4) ε4 (+)/statin (+). Dementia severity was assessed by a δ homolog: “dHABS.” A mediation model was stratified on statin use and moderation effects tested by a chi‐square difference.

RESULTS

Plasma CRP level decreased with ε4 allelic dose. Statins had no effect on the dHABS d‐score in non‐carriers but were associated with better scores in carriers. Treated carriers did not have more severe dementia than non‐carriers. Statin use moderated the mutual adjusted effects of APOE and CRP. CRP was not a mediator of APOE's effect.

DISCUSSION

Statins may provide a protective effect on the dementia severity of ε4 carriers.

Highlights

δ is a dementia‐specific phenotype related to general intelligence “g” and is assessed via a “d‐score.”

Apolipoprotein E (APOE) and plasma C‐reactive protein (CRP) are independently associated with δ.

Plasma CRP decreases with ε4 allelic dose.

Statins were associated with better (less demented) d‐scores in ε4 carriers but had no effect in non‐ε4 carriers.

Treated ε4 carriers did not have more severe dementia than non‐carriers.

Statin use moderated the effects of APOE and CRP on δ.

CRP was not a mediator of APOE's effect on δ.
Cascade In Situ Self‐Assembly and Bioorthogonal Reaction Enable the Enrichment of Photosensitizers and Carbonic Anhydrase Inhibitors for Pretargeted Cancer Theranostics
Authors: Wen Xidan , Zeng Wenhui , Zhang Junya , Liu Yili , Miao Yinxing , Liu Shaohai , Yang Yanling , Xu Jing‐Juan , Ye Deju
Published: December 2023

We report here a tumor‐pretargted theranostic approach for multimodality imaging‐guided synergistic cancer PDT by cascade alkaline phosphatase (ALP)‐mediated in situ self‐assembly and bioorthogonal inverse electron demand Diels–Alder (IEDDA) reaction. Using the enzymatic catalysis of ALP that continuously catalyses the dephosphorylation and self‐assembly of trans‐cyclooctene (TCO)‐bearing P‐FFGd‐TCO, a high density of fluorescent and magnetic TCO‐containing nanoparticles (FMNPs‐TCO) can be synthesized and retained on the membrane of tumor cells. They can act as ‘artificial antigens’ amenable to concurrently capture lately administrated tetrazine (Tz)‐decorated PS (775NP‐Tz) and carbonic anhydrase (CA) inhibitor (SA‐Tz) via the fast IEDDA reaction. This two‐step pretargeting process can further induce FMNPs‐TCO regrowth into microparticles (FMNPs‐775/SA) directly on tumor cell membranes, which is analyzed by bio‐SEM and fluorescence imaging. Thus, efficient enrichment of both SA‐Tz and 775NP‐Tz in tumors can be achieved, allowing to alleviate hypoxia by continuously inhibiting CA activity and improving PDT of tumors. Findings show that subcutaneous HeLa tumors could be completely eradicated and no tumor recurred after irradiation with an 808 nm laser (0.33 W cm−2, 10 min). This pretargeted approach may be applied to enrich other therapeutic agents in tumors to improve targeted therapy.
Synthesis of a graft‐functionalized flame retardant based on DOPO and its application on the surface of terylene/cotton fabrics
Authors: Shi Zhehang , Luo Fubin , Li Hongzhou , Chen Denglong
Published: December 2023

Terylene/cotton (TC) fabrics are widely used in the textile industry because of their superior softness and durability. In addition, its high combustibility leads to a great safety hazard, and the droplet phenomenon during combustion is particularly serious. 9‐oxa‐10‐phospha‐9,10‐dihydrophenanthrene 10‐oxide (DOPO) and its derivatives are frequently used as eco‐friendly flame retardants in large quantities in substrates. It would be difficult to apply to the surface of the fabric, and the addition of large amounts would lead to a decrease in the mechanical properties. Therefore, it is necessary to design a strategy for graft‐functionalized flame retardants that can be applied to surfaces. Here, this study reported a washing‐fastness flame‐retardant coating (DOPO‐p) synthesized from DOPO and p‐hydroxybenzaldehyde (p‐HBA), coatings with a low weight growth and high flame‐retardant efficiency are prepared by the strategy of dissolving with organic solvents. Water and dry‐cleaning tests showed excellent washing fastness of TC fabrics. In the limiting oxygen index (LOI) test, the finished fabric achieved a LOI value of 22.9%. In the cone calorimetry test, the peak of heat release rate of the finished fabric is decreased by 27% and CO2 release is reduced by 29% when the coating weight growth was only 3.3 wt%.
Experimentelle Bestimmung der Ermüdungseigenschaften von heftgeschweißter Bewehrung
Authors: Gaßner Kerstin , Träger Wolfgang , Reichenbach Sara , Kollegger Johann
Published: December 2023

Am Institut für Tragkonstruktionen der TU Wien wurden in den letzten Jahren unterschiedliche Einsatzmöglichkeiten für Halbfertigteilelemente im Brückenbau entwickelt. Aufgrund der Wichtigkeit der Betrachtung von Materialermüdung ist ein besonderes Augenmerk auf die eingebaute heftgeschweißte Bewehrung zu legen. Nach einem kurzen Überblick über die Einsatzmöglichkeiten wie auch die allgemein gültigen Regelungen in Bezug auf Materialermüdung werden im vorliegenden Beitrag experimentelle Untersuchungen zur Bestimmung der Ermüdungseigenschaften von heftgeschweißter Bewehrung vorgestellt. Die Eigenschaften wurden einerseits mithilfe von 18 zentrischen Zugversuchen an Bewehrungsstäben mit angehefteten Querstäben, anderseits mithilfe von zwölf großformatigen, auf Biegung beanspruchten Balkenelementen untersucht. Als wesentliche Erkenntnis kann das Vorhandensein einer Restphase bei einem realitätsnahen System genannt werden, wodurch sich ein Zeitraum zwischen dem ersten Stabbruch und dem Totalkollaps des Systems ergibt. Dieses Verhalten wird für die Anwendung in der Praxis als vorteilhaft gesehen, da sich eine Reaktionszeit für die Setzung von etwaigen baulichen Maßnahmen ergibt.
Bayesian optimal stepped wedge design
Authors: Singh Satya Prakash
Published: December 2023

Recently, there has been a growing interest in designing cluster trials using stepped wedge design (SWD). An SWD is a type of cluster–crossover design in which clusters of individuals are randomized unidirectional from a control to an intervention at certain time points. The intraclass correlation coefficient (ICC) that measures the dependency of subject within a cluster plays an important role in design and analysis of stepped wedge trials. In this paper, we discuss a Bayesian approach to address the dependency of SWD on the ICC and robust Bayesian SWDs are proposed. Bayesian design is shown to be more robust against the misspecification of the parameter values compared to the locally optimal design. Designs are obtained for the various choices of priors assigned to the ICC. A detailed sensitivity analysis is performed to assess the robustness of proposed optimal designs. The power superiority of Bayesian design against the commonly used balanced design is demonstrated numerically using hypothetical as well as real scenarios.
Restoration of historic gypsum masonry
Authors: Eckart Angela , Burkert Toralf
Published: December 2023

Incompatibilities between the original substance containing gypsum in historically significant buildings and modern hydraulic repair materials have been known for over 80 years. However, as a result of expansion phenomena, a lot of culturally and historically valuable buildings in Germany have been irretrievably destroyed in recent decades. In a project of the Deutsche Bundesstiftung Umwelt, the question of which materials and which technologies are suitable for the renovation of masonry containing gypsum was investigated.
Modeling of the “grain – binding shell” system for refractory concretes structure
Authors: Nagorniy Andriy
Published: December 2023

Among with the fundamentally new concepts toward of the refractory concretes thermal‐shock resistance increasing is obtaining products with specified properties by controlling their structural parameters. The structure of refractory materials is one of the most important and common features and is characterized by the distribution of structural elements (grains, bond, macro‐ and microdefects), their quantitative ratio and relationship.

Industrial refractory concretes are made of relatively large grains (up to 4 mm) and dispersed particles (less than 0.06 mm), the quantitative ratio, chemical and mineralogical composition of which varies within enough wide limits. As a result, the concrete structure is formed with a high degree of heterogeneity, different thermo‐mechanical properties of its several components, as well as with a significant content of pores and microcracks. In addition, a change in temperature causes the appearance of significant internal stresses and general deformation or destruction of the concrete.
CO2‐arme Bindemittel zur Herstellung hoch beanspruchter Betone
Authors: Rasch Stefan , Pulkin Maxim , Neumann Thomas
Published: December 2023

Kurzfassung

Der Einsatz alkalisch aktivierter Bindemittel (AAB) bzw. Geopolymere wird im Wesentlichen durch zwei Gründe motiviert. Dem ersten Grund liegt der Nachhaltigkeitsaspekt zugrunde bzw. die Reduzierung herstellbedingter CO2‐Emissionen. Der zweite Grund liegt in der hohen chemischen und thermischen Stabilität der entsprechenden Betone begründet. Ein sinnvoller Einsatz von AAB und Geopolymeren ergibt sich immer dann, wenn Betoneigenschaften erreicht werden, die mit derzeitigen Normenzementen nicht möglich wären. Aufgrund des hohen Wasseranspruchs wurden Geopolymere in der Vergangenheit nicht oder nur in Nischenprodukten eingesetzt. Unter der Voraussetzung, dass bei der Betonherstellung sehr niedrige Wasser/Bindemittel‐Werte eingestellt werden, können AAB‐ oder Geopolymerbetone ein äußerst dichtes und widerstandsfähiges Mikrogefüge ausbilden. Neuartige Zusatzmittel ermöglichen inzwischen auch für diese Betone sehr gute Verarbeitungseigenschaften. Insbesondere der hohe chemische Widerstand und der hohe thermische Widerstand von AAB‐ und Geopolymerbetonen führen zu einer Erweiterung der bisherigen Betonanwendungen. Die Entwicklung des Bindemittels Duracrete® GP zielt genau auf diese Anwendungsfälle. Beispielhaft werden im Folgenden Anwendungsbeispiele aufgeführt bei denen Werkstoffe auf Basis von Kunststoff, GFK, Steinzeug oder Keramik durch Duracrete® GP – Beton ersetzt wurden.
Studies on the compatibility of different superplasticizers with alkaline activators for low calcium geopolymer binders.
Authors: Partschefeld Stephan , Tutal Adrian , Halmanseder Thomas , Osburg Andrea
Published: December 2023

The cement industry is coming into focus, as the annual production of around 4 Gt of cement is responsible for the emission of 1.5 Gt of CO2 and thus for over 8 % of anthropogenic CO2 emissions. This leads to the search for alternative binders. Such binders are calcined clays, which are available worldwide but vary greatly in their chemical and mineralogical composition. In many studies, particularly low‐calcium metakaolin is used as calcined clay, which reacts to form a low‐calcium aluminosilicate binder when mixed with a calcium‐free alkaline activator. The adjustment of the properties in the fresh state, especially regarding the consistency of these binders, is almost exclusively achieved by the addition of water, since commercially available superplasticizers are usually ineffective in low calcium geopolymer systems. The objective of this study was to investigate various PCE superplasticizers (MPEG‐, IPEG‐, HPEG‐PCE) with respect to their stability in different alkaline activators (NaOH, KOH, sodium, and potassium silicate solutions). The effectiveness of superplasticizers in low calcium geopolymer binders was verified by rheological tests. Size exclusion chromatography was used to investigate if structural degradation of the superplasticizers occurs. The investigated PCE superplasticizers showed no liquefying effect in the low calcium geopolymer system. This is due to a degradation process, i.e., the hydrolysis of the PEG side chains depending on the alkalinity of the activator.
40 Years of PCE Superplasticizers ‐ Current State of the Art and Future Perspectives
Authors: Lei Lei , Plank Johann
Published: December 2023

With over 15 Mio tons of annual production, polycarboxylates (PCEs) currently dominate the global superplasticizer market. Among them, HPEG and IPEG PCEs have attained a prominent position as they present the most cost‐effective PCEs known at present. Recently, new vinyl ether PCEs designated as EPEG and GPEG PCEs were introduced, thus broadening the family of VPEG PCEs. Furthermore, novel phosphated comb polymers which significantly reduce the stickiness of concrete have been developed. For calcined clay blended cements, HPEG PCEs of specific molecular design as well as zwitterionic (amphoteric) PCEs have proven to be highly effective. Moreover, NaOH activated AAS binder systems were successfully fluidized with APEG or HPEG PCEs exhibiting particularly short side chains (nEO < 10). While for Na2CO3, Na2SiO3 and Na2SO4 activated systems, the search for effective superplasticizers is still ongoing. This review underlines the critical role which chemical admixtures will play in the successful transition of the construction industry to a net zero carbon age.
Gipsputz auf Basis von recyceltem Gips
Authors: Nowak Saskia , Böcker Aletta , Dreuse Heike , Crome Tobias , Losch Grit , Schuler Hilaria , Malsch Paul
Published: December 2023

Kurzfassung

Mit der Umsetzung des Kohleausstiegs, und der damit einhergehenden Verringerung der REA‐Gips‐Verfügbarkeit, wurde damit begonnen Recycling‐Gips (RC‐Gips) aus Gipsabfall und Gipsanfallstoffen zu gewinnen. Dabei ist momentan nur das Recycling von Gipskartonplatten etabliert. Die Verwendung von RC‐Gips für andere Bauprodukte als Gipskartonplatten, wie z.B. Estrich‐, Mauer‐ oder Putzmörtel ist praktisch unerforscht.

Vorgestellt werden Forschungsergebnisse zur Entwicklung eines RC‐Maschinengipsputzes, dessen Verarbeitungsverhalten und Nutzungseigenschaften marktüblichen Produkten und den Anforderungen nach Norm entsprechen soll.
Mechanisms of thixotropy in cement suspensions considering influences from shear history and hydration
Authors: Link Julian , Strybny Bastian , Divoux Thibaut , Sowoidnich Thomas , Coenen Max , Gstöhl Stefan , Schlepütz Christian M. , Zuber Marcus , Hellmann Steffen , Rößler Christiane , Lützenkirchen Johannes , Heberling Frank , Manneville Sébastien , Schäfer Thorsten , Ludwig Horst‐Michael , Haist Michael
Published: December 2023

The rheological properties of fresh concrete are a direct function of the interaction behaviour of the granular inventory of the concrete (i.e., gravel, sand and cement) and especially of the colloidal fractions of cement. Under low shear stresses, agglomeration of colloidal particles is observed, while at high shear stresses, dispersion of these agglomerates occurs. Besides the agglomeration state, the formation of shear banding, zones with concentrated shear flow, is another controlling mechanism of the flow behaviour of cement suspensions. Rheological creep tests in this study are focused on investigating the influence of shear history and hydration process on thixotropy of cement suspension. In this paper, the meaning of the word thixotropy is slightly extended to additionally encompass rheological aging and hydration effects. Selected samples were analyzed by coupling a rheometer to synchrotron X‐ray tomography to gain insight into the shear‐induced microstructural changes during shear start‐up tests. The observations show heterogeneities in the velocity profile in the shear gap and the development of shear banding.
Material‐minimised construction with extruded textile reinforced concrete
Authors: Kalthoff Matthias , Cruz Cynthia Morales , Raupach Michael , Matschei Thomas
Published: December 2023

The use of textile reinforced concrete (TRC) is particularly suitable for producing sustainable, material‐minimised components, as it allows for a significant reduction in the amount of concrete cover required compared to steel reinforced concrete (SRC). Instead of steel, fibres made of glass, aramid or carbon are used as reinforcement, which are processed from rovings into textiles with a polymer or mineral impregnation. Among these, carbon reinforcements have the highest tensile strength and alkali resistance, making them the most durable in concrete and requiring less maintenance over time. An innovative approach is the production of TRC structures by means of extrusion, in which the stiff, fresh concrete is continuously pressed through a shaping mouthpiece, giving the product its final shape. Within the scope of the CRC/Transregio 280, a new mouthpiece was developed that enables the horizontal introduction of stiff, impregnated textiles. The carbon TRC produced in this process showed a textile stress of up to 4,000 MPa. Additionally, solutions are presented that allow the characterization of stiff, fresh concrete and technical limits for shaping fresh, extruded TRC elements. The potential of this new production method is illustrated through the example of a compound component made of extruded TRC elements.
α‐calcium sulfate hemihydrate formation using natural anhydrite as raw material
Authors: Eicheler Christina , Heisig Anne , Hilbig Harald , Machner Alisa
Published: December 2023

This study investigates the potential of α‐HH formation from gypsum originating from activated and hydrated natural anhydrite. For this, gypsum was prepared from natural anhydrite and treated in an autoclave process under hydrothermal conditions (150 mbar and 130 °C). For comparison, fgd‐gypsum was treated accordingly. Succinic acid, maleic acid and additional α‐HH seeds were used as crystallization aids. QXRD results show the transformation of gypsum into hemihydrate after a residence time of 8 h and 4 h. SEM images distinguish the α‐HH and β‐HH modifications. For fgd‐gypsum pellets, the β‐HH modification predominates. Gypsum from natural anhydrite shows α‐HH crystals with succinic acid and without crystallization aid. When maleic acid is present, crystals appear as intermediates between α‐HH and β‐HH. To isolate the effect of the crystallization aids, α‐HH and succinic acid were used separately and simultaneously. SEM images indicate the formation of α‐HH from β‐HH. The shapes of the original β‐HH conglomerates are still visible, yet acicular crystals with smooth surfaces (α‐HH) are visible at a high magnification. Longest crystals appear when α‐HH and succinic acid are used simultaneously indicating a synergetic effect of both crystallization aids.
Autogenous Self‐healing of CTRC Repair Layers Exposed to Tensile Threshold Loading
Authors: Cruz Cynthia Morales
Published: December 2023

The experimental investigations presented in this paper contribute to fill the knowledge gaps on the subject of autogenous self‐healing of DURTEX layers for the surface repair of cracked or cyclic crack opening of concrete and reinforced concrete structures. Composite specimens, so‐called crack distribution specimens, were subjected to at least 1000 and up to 6900 cycles. Investigations show that neither the crack characteristics (e. g. crack width, crack geometry) change nor the mechanical properties (e. g. adhesive tensile strength or tensile load‐bearing behavior) are reduced compared to the reference specimens as a result of cyclic loading with both pore and crack water pressure. Also, the self‐healing potential of a selected material combination is demonstrated despite cyclic loading. It was observed that cracked DURTEX layers with wmax = 0.116 mm, under cyclic loading (Δwop = 0.6 mm) at a constant test speed set to 0.05 mm/min (piston controlled) with a 5 m pore and crack water pressure can self‐heal themselves leading to water tightness after 14 days. Chemical‐mineralogical analysis using X‐ray diffraction (XRD) on material taken from the cracked surface of the specimen evidenced the formation of CaCO3 as calcite.
Faserbewehrter UHPC auf Basis von alkalisch aktivierten Bindemittel
Authors: Wetzel Alexander , Link Janna , Middendorf Bernhard
Published: December 2023

Kurzfassung

Die mechanische Leistungsfähigkeit von faserverstärktem Ultrahochleistungsbeton auf der Grundlage alkalisch aktivierter Schlacke wurde untersucht, wobei der Schwerpunkt auf der Verwendung von Stahlfasern lag. Die Biegezugfestigkeit ist im Vergleich zu UHPC auf der Basis Portlandzement als Bindemittel erhöht. Die Korrelation der Biegezugfestigkeitsprüfung mit Faserauszugsversuchen ergab eine Verbesserung des Verbundverhaltens in der Grenzflächen‐Übergangszone des AAM‐UHPC im Vergleich zum OPC‐UHPC. Bei Vergleichen von Mehrfachfaserauszugsversuchen mit den Biegezugfestigkeiten zeigt sich eine Tendenz zu höheren Festigkeiten für Edelstahlfasern, während bei dem Faserauszug die messingbeschichteten Stahlfasern eine höhere Verbundstärke aufweisen. Zusätzliche Auszugsversuche unter Variation des Auszugswinkel zeigen jedoch eine Bestätigung der Biegezugfestigkeitsergebnisse. Bei schrägem Faserauszug weisen die Edelstahlfasern Vorteile auf. Mittels μ‐CT durchgeführte in‐situ Auszugsversuche weisen auf einen stärkeren Verbund von Edelstahlfasern im schrägen Auszug auf. Dies ist vermutlich auf einen stärkeren Reibungsverbund infolge einer stärkeren Topographie im Vergleich zu den messingbeschichteten Stahlfasern zurückzuführen. Im Vergleich zum geraden Auszug scheint die Topographie der Edelstahlfasern einen stärkeren Effekt zu bewirken.
Characterization of recycled sands and aggregates from selective separation
Authors: Vargas‐Serrano Encarnacion , Tian W. , Mikanovic N. , Skocek Jan
Published: December 2023

The use of recycling materials from demolished concrete as raw material for structural application represents an opportunity for decreasing the consumption of primary raw materials and waste generation, thus increasing global sustainability. However, this potential is nowadays not fully exploited due to standards limitations and concerns from the construction industry about the negative effect of the recycled sand in the fresh and hardened concrete performance. Thus, most of the recycled sand produced is only reused as roadbed or dumped in the landfill, whereas the recycled coarse aggregate is commonly downcycled when used for lower‐grade applications.

This paper presents an overview of the quality properties of recycled materials obtained through advanced recycling technologies designed to separate high‐quality sand and coarse aggregates from hardened cement paste in demolished concrete. The study focuses on evaluating the selective separation technologies implemented in various industrial pilots and examining how the properties of recycled sands and aggregates compare to those of virgin materials of good quality, and their impact on performance.

The test results indicate that there is a strong link between recycled sand quality and its effect on workability and strength development of cement‐based materials. This study also identifies critical aggregate parameters based on which one can come up with realistic replacement levels of natural with recycled sands and aggregate without compromising performance in fresh and hardened state. Our intention is to provide sufficient evidence to specifiers and designers that good quality recycled sands can be used in larger amounts in structural concrete.
Use of treated municipal waste incinerator ashes as concrete aggregate after fragmentation and sorting
Authors: Siebert Björn , Hirsch Marius , Leiss Norbert , Spektor Vitaliy , Vollpracht Anya , Winkler Rebecca , Wolf Christian
Published: December 2023

Annually about 5.7 million tons of waste incinerator ash accumulate in Germany through the incineration of municipal waste. The new method of electrodynamic fragmentation allows waste incinerator ashes with complex material compositions to be broken at material interfaces and then sorted into materially pure components. The aim of current ASHCON research project is to substitute natural aggregate of the grain fraction 2/8 mm in conventional formulations for ready‐mixed concrete and concrete blocks by these secondary raw materials in order to keep them within the material cycle and reduce the use of primary raw materials. Since the utilization of fragmented waste incinerator ashes in concrete must be below the limit values with regard to possible pollutant concentrations (e.g. heavy metal concentrations), the suitability of a so‐called non‐destructive neutronic analysis method on real samples is also being investigated within the ASHCON project. The first results of sample collection, preparation and analysis as well as material properties of the produced concretes with the implementation of mineral residues from waste incinerator ashes are presented in this paper.
Phase formation and hydration of alumina cements on the basis of cobalt‐molybdenum‐containing waste
Authors: Logvinkov Sergii , Korohodska Alla , Shabanova Halyna , Levadna Svitlana
Published: December 2023

The subject of the research is features of synthesis of alumina cements on the basis of compositions of system CaO – CoO – Al2O3 – MoO3 with use of cobalt‐molybdenum‐containing waste for reception of refractory materials with a complex of the set properties. The processes of phase formation in raw mixtures have been investigated. X‐ray phase studies of clinkers fired at different temperatures and holding times proved that as a result of the interaction of the raw materials of the mixture in the material synthesizes a mixture of hydraulically active calcium mono‐ and di‐aluminate and refractory cobalt spinel, which provides the resulting complex high strength, accelerated curing time, fire resistance. The absence of phases corresponding to molybdenum compounds is explained by the fact that they are part of hydraulically active aluminates as limited solid solutions, deforming the crystal lattice and increasing hydraulic activity. Thus, it was found that the high strength of cement is due to the presence of calcium hydroaluminates such as C2AH8, aluminum hydroxide, as well as unhydrated grains of calcium aluminates, which will contribute to further long‐term strength. It is this coexistence of phases in both the crystalline and colloidal states provide high strength cement stone.
Sulfate consumption during the hydration of Alite and its influence by SCMs
Authors: Maier Matthias , Scherb Sebastian , Thienel Karl‐Christian
Published: December 2023

SCMs with a large specific surface area, such as calcined clays or fine limestone powder, can significantly accelerate the occurrence of the aluminate heat flow peak during the early hydration of blended cements. These systems therefore require a higher amount of sulfate. While this effect has been drawn back to the sulfate incorporation into C‐S‐H, which is formed more rapidly due to the filler effect, it has been recently shown that in systems with high amounts of metakaolin, the sulfate balance is influenced by further mechanisms. This study provides new results on the influence of aluminum‐rich and aluminum‐free SCMs on the early hydration of alite in presence of calcium sulfate. A synthesized alite was blended with 5 wt% of anhydrite and its hydration was investigated by isothermal calorimetry and in‐situ XRD at a w/b ratio of 0.5. It was shown that the formed C‐S‐H is able to take up the calcium and sulfate ions, indicated by a depletion of the solid anhydrite after approximately 20 hours. This process is significantly accelerated by incorporating 30 wt% of a fine limestone filler. The addition of metakaolin leads to an acceleration of the alite hydration compared to the reference as well, but to a significantly lower extend compared to the limestone. However, this system requires a lower degree of alite reaction to reach sulfate depletion. This indicates that in metakaolin‐rich systems, the sulfate demand is influenced by further effects. The results from in‐situ‐XRD reveal that significant ettringite formation is taking place in the metakaolin‐blended system already during the first hours of hydration. Correlations between the degree of alite hydration and the rate of sulfate depletion provide new insights into the mechanisms affecting the sulfate balance and early hydration of blended cements.
Challenges for Embedding RFID Sensors in Reinforced Concrete for Low‐effort Structural Health Monitoring
Authors: Walther Christian , Alkam Feras , Nguyen‐Tuan Long , Lieboldt Matthias , Lahmer Tom
Published: December 2023

The structural health of civil infrastructure can be monitored using non‐destructive testing methods and wireless sensor technology. Buildings are often made of reinforced concrete, in which the sensors can be embedded during construction. The implementation of sensor‐based monitoring therefore fundamentally requires robust electronics. The wireless sensors must meet the special requirements of different areas such as communication, durability in the concrete, and compatibility with future readers. Taking into account previous approaches from practice and research, an elicitation of basic requirements for a Radio Frequency Identification (RFID) sensor system that can be embedded in concrete was carried out. Specific problems related to embedding electronic sensors in concrete and their design are investigated. Simple RFID sensor systems have been developed that allow operation without cables or batteries. The main sensor requirements are listed accordingly. Challenges and issues that need to be considered when using RFID sensors in concrete are described. Finally, the “life cycle” of a sensor system embedded in reinforced concrete is briefly discussed.
Nachträgliche Beschleunigung einer verzögerten Zementhydratation mit Kristallisationskeimen
Authors: Unbehau Sophie , Sowoidnich Thomas , Müller Matthias , Goretzki Lothar , Ludwig Horst‐Michael
Published: December 2023

Kurzfassung

Verzögerer oder verzögernd wirkende Fließmittel werden im Betonbau eingesetzt, um ausreichend lange Verarbeitungszeiten zu realisieren, insbesondere bei hohen Temperaturen. Das zielsichere Einhalten der gewünschten Verzögerungsspanne kann dabei problematisch sein. Starke Abweichungen können zu Störungen des Bauablaufs führen. Durch eine gezielte Aufhebung der Verzögerungswirkung kurz vor dem Einbau des Betons kann hier eine deutlich höhere Anwendungssicherheit erreicht werden. Die Machbarkeit dieses Ansatzes wurde in der vorliegenden Studie untersucht. Hierzu wurde die Hydratation eines Portlandzementes gezielt verzögert und zu verschiedenen, späteren Zeitpunkten durch Zugabe von Keimbildnern wieder angeregt. Die Auswirkungen auf die Kinetik der Zementhydratation, auf das Erstarrungsverhalten und die Festigkeitsentwicklung wurden charakterisiert

Die Ergebnisse zeigen, dass die gezielte Verzögerung der Zementhydratation durch eine spätere Zugabe von Kristallisationskeimen kompensiert werden kann (Stichwort: setting on‐demand). Damit kann der Baupraxis ein zusätzliches Instrument zur Hand gegeben werden, um die Anwendungssicherheit von Verzögerern im Betonbau zu erhöhen. Zudem kann dieser Ansatz das Potential bieten, das Erstarrungsverhalten von Spritzbeton positiv zu beeinflussen.
Recycling of construction waste as an innovative direction of the program of post‐war reconstruction of destroyed cities
Authors: Shyshkin Eduard , Chernonosova Tetiana , Haiko Yurii , Ivasenko Viktoriia , Krasnokutska Iuliia
Published: December 2023

There are officially more than 5.5 thousand dumps in Ukraine, landfills with a total area of more than 9,000 hectares, and there are more than 2000 illegal dumps. The issue of waste disposal (garbage) has always been very acute, not only during the war, a significant part of this waste is construction waste. During the hostilities, many Ukrainian cities and settlements suffered various types of destruction, and some suffered almost the greatest destruction of various objects of urban infrastructure. All this contributed to the emergence of a large amount of demolition waste. The article analyzes the current state of management of demolition waste in Ukraine. The goals and objectives of recycling construction waste in the conditions of post‐war reconstruction of destroyed urban areas are formulated. The results of theoretical studies of methods of utilization of demolition waste by their reuse in construction are given. The preferred types of construction waste in case of destruction of buildings include clogged soil, asphalt, stone materials, brick, concrete and reinforced concrete, wood, ceramic tiles, etc. Each of these types of demolition waste needs a separate recycling. The article gives the classification and structure of demolition waste and defines, what operations to handle it are required. The requirements for the arrangement of temporary storage of construction waste are formulated. Prospects for the development of recycling of demolition waste in Ukraine are considered. The ways of reuse in construction of demolition waste components are proposed. Recommendations of measures of step‐by‐step management of construction waste in Ukraine were provided.
Entwicklung von Porenkeramik‐Sensorelementen für ein Monitoring des Trocknungsverlaufs von Calciumsulfat‐Estrichen
Authors: Helbig Stefan , Hildebrandt Stefanie , Bonitz Frank , Wagner Ralf , Haase Daniela , Adler Jörg , Lizarazu Jorge , Damaschke Anja , Schulz Tabea , Ulanov Alexander , Kersten Hans‐Jörg
Published: December 2023

Kurzfassung

Ausgehend von der Analyse der Porenstruktur typischer Calciumsulfat‐Estriche wurde eine Porenkeramik entwickelt. Ziel war dabei, ein keramisches Material mit ähnlicher Porenverteilung und folglich ähnlichen Feuchtespeichereigenschaften wie die von typischen Calciumsulfat‐Estrichen zu erhalten. Die Feuchtespeicherfunktionen der Calciumsulfat‐Estriche und der entwickelten Porenkeramiken wurden mit einem Taupunkt‐Potentiameter gemessen. Dadurch war eine detaillierte Charakterisierung der Feuchtespeichereigenschaften im überhygroskopischen Bereich möglich. Es wurden auch die dielektrischen und lichtoptischen Eigenschaften der Porenkeramik bestimmt. Aus der Porenkeramik wurden dielektrische und lichtoptische Sensoren sowie die zugehörige Technik für die kontinuierliche Messwerterfassung entwickelt. Die Sensoren wurden in Estrich‐Versuchsflächen während der Herstellung eingebettet und durch Monitoring während einer Trocknung der Estriche bis zur Belegreife getestet. Bei Estrichen, deren Feuchtespeicherfunktion hinreichend mit der Feuchtespeicherfunktion der Porenkeramik übereinstimmte, zeigte sich dabei eine gute Korrelation der Sensorsignale mit den durch Darr‐ und CM‐Verfahren bestimmten Feuchtegehalten.
Leistungsbezogene Bewertung der Dauerhaftigkeit von Betonbauwerken durch baustellentaugliche Abnahmeprüfungen
Authors: Ov David , Lozano‐Valcarcel Juan Mauricio , Breitenbücher Rolf , Kränkel Thomas , Gehlen Christoph
Published: December 2023

Kurzfassung

Für die Dauerhaftigkeit eines Bauwerks ist die Qualität des eingebauten Betons entscheidend. Allerdings sind bislang für die dauerhaftigkeitsrelevanten Betoneigenschaften noch keine direkten Bewertungskriterien definiert worden. Die Qualität des eingebauten Betons wird in der Regel an separat hergestellten Proben nachgewiesen. Vergangene Forschungsarbeiten haben gezeigt, dass die am Bauwerk erzielten Betoneigenschaften von denen der separat hergestellten Proben erheblich abweichen können. In dem künftigen performance‐basierten Dauerhaftigkeitskonzept ist zudem die direkte Prüfung der relevanten Parameter (Karbonatisierungsrate, Chlorideindringung usw.) mit einem vergleichsweise hohen Aufwand verbunden. Es wird in der Praxis ohnehin nicht umsetzbar sein, die dauerhaftigkeitsrelevanten Eigenschaften im hinreichenden Umfang über die direkten Prüfverfahren zu überwachen. Vielmehr ist die Qualität des Betons auf der Baustelle durch indirekte Schnellprüfverfahren (z.B. Wenner‐Sonde) zu bewerten, die damit verbunden in engeren Zeitabständen durchführbar und somit auch baustellengerecht sind. Hierzu liegen jedoch noch keine ausreichenden Erfahrungen über die Anwendbarkeit und Reproduzierbarkeit auf den Baustellen vor.