bluuebunny/crossref_metadata_2025 huggingface dataset:
Microenvironment M1/M2 macrophages and tumoral progression vary within C57BL/6 mice from same substrain in prostate cancer model
Authors: Hernández-Peralta P. , Chacón-Salinas R. , Gracia-Mora M. I. , Soldevila G. , Moreno-Rodríguez J. , Cobos-Marín L.
Published: July 2024

Cancer mice models are critical for immune-oncology research; they provide conditions to explore tumor immunoenviroment aiming to advance knowledge and treatment development. Often, research groups breed their own mice colonies. To assess the effect of C57BL/6 mice breeding nuclei in prostate cancer development and intratumoral macrophage populations, an isotransplantation experiment was performed. C57BL/6J mice from two breeding nuclei (nA and nB) were employed for prostate adenocarcinoma TRAMP-C1 cell implantation; tumor growth period and intratumoral macrophage profile were measured. BL/6nB mice (54%) showed tumor implantation after 69-day growth period while BL/6nA implantation reached 100% across tumor growth period (28 days). No difference in total macrophage populations was observed between groups within several tumoral regions; significantly higher M2 macrophage profile was observed in tumor microenvironments from both mice groups. Nevertheless, BL/6nB tumors showed around twice the population of M1 profile (11–27%) than BL6nA (4–15%) and less non-polarized macrophages. The M1:M2 average ratio was 1:8 for group A and 1:4 for B. Our results demonstrate different tumor progression and intratumoral macrophage populations among mice from the same substrain. Data obtained in this study shows the relevance of animal source renewal for better control of murine cancer model variables.
Study on the Infrared and Raman spectra of Ti3AlB2, Zr3AlB2, Hf3AlB2, and Ta3AlB2 by first-principles calculations
Authors: Wang Shengzhao , Chen Lanli , Hao Haoshan , Qiao Chong , Song Jinfan , Cui Chaojun , Liu Bin
Published: July 2024

In this paper, the crystal geometry, electronic structure, lattice vibration, Infrared and Raman spectra of ternary layered borides M3AlB2 (M = Ti, Zr, Hf, Ta) are studied by using first principles calculation method based on the density functional theory. The electronic structure of M3AlB2 indicates that they are all electrical conductors, and the d orbitals of Ti, Zr, Hf, and Ta occupy most of the bottom of the conduction band and most of the top of the valence band. Al and B have lower contributions near their Fermi level. The lightweight and stronger chemical bonds of atom B are important factors that correspond to higher levels of peak positions in the Infrared and Raman spectra. However, the vibration frequencies, phonon density of states, and peak positions of Infrared and Raman spectra are significantly lower because of heavier masses and weaker chemical bonds for M and Al atoms. And, there are 6 Infrared active modes A2u and E1u, and 7 Raman active modes, namely A1g, E2g, and E1g corresponding to different vibration frequencies in M3AlB2. Furthermore, the Infrared and Raman spectra of M3AlB2 were obtained respectively, which intuitively provided a reliable Infrared and Raman vibration position and intensity theoretical basis for the experimental study.
Enhanced brackish water desalination in capacitive deionization with composite Zn-BTC MOF-incorporated electrodes
Authors: Ghorbanian Amirshahriar , Rowshanzamir Soosan , Mehri Foad
Published: July 2024

In this study, composite electrodes with metal–organic framework (MOF) for brackish water desalination via capacitive deionization (CDI) were developed. The electrodes contained activated carbon (AC), polyvinylidene fluoride (PVDF), and zinc-benzene tricarboxylic acid (Zn-BTC) MOF in varying proportions, improving their electrochemical performance. Among them, the E4 electrode with 6% Zn-BTC MOF exhibited the best performance in terms of CV and EIS analyses, with a specific capacity of 88 F g−1 and low ion charge transfer resistance of 4.9 Ω. The E4 electrode showed a 46.7% increase in specific capacitance compared to the E1 electrode, which did not include the MOF. Physicochemical analyses, including XRD, FTIR, FESEM, BET, EDS, elemental mapping, and contact angle measurements, verified the superior properties of the E4 electrode compared to E1, showcasing successful MOF synthesis, desirable pore size, elemental and particle-size distribution of materials, and the superior hydrophilicity enhancement. By evaluating salt removal capacity (SRC) in various setups using an initially 100.0 mg L−1 NaCl feed solution, the asymmetric arrangement of E1 and E4 electrodes outperformed symmetric arrangements, achieving a 21.1% increase in SRC to 6.3 mg g−1. This study demonstrates the potential of MOF-incorporated electrodes for efficient CDI desalination processes.
The effect of elimination of gibbs ringing, noise and systematic errors on the DTI metrics and tractography in a rat brain
Authors: Mazur-Rosmus Weronika , Krzyżak Artur T.
Published: July 2024

Diffusion tensor imaging (DTI) metrics and tractography can be biased due to low signal-to-noise ratio (SNR) and systematic errors resulting from image artifacts and imperfections in magnetic field gradients. The imperfections include non-uniformity and nonlinearity, effects caused by eddy currents, and the influence of background and imaging gradients. We investigated the impact of systematic errors on DTI metrics of an isotropic phantom and DTI metrics and tractography of a rat brain measured at high resolution. We tested denoising and Gibbs ringing removal methods combined with the B matrix spatial distribution (BSD) method for magnetic field gradient calibration. The results showed that the performance of the BSD method depends on whether Gibbs ringing is removed and the effectiveness of stochastic error removal. Region of interest (ROI)-based analysis of the DTI metrics showed that, depending on the size of the ROI and its location in space, correction methods can remove systematic bias to varying degrees. The preprocessing pipeline proposed and dedicated to this type of data together with the BSD method resulted in an even − 90% decrease in fractional anisotropy (FA) (globally and locally) in the isotropic phantom and − 45% in the rat brain. The largest global changes in the rat brain tractogram compared to the standard method without preprocessing (sDTI) were noticed after denoising. The direction of the first eigenvector obtained from DTI after denoising, Gibbs ringing removal and BSD differed by an average of 56 and 10 degrees in the ROI from sDTI and from sDTI after denoising and Gibbs ringing removal, respectively. The latter can be identified with the amount of improvement in tractography due to the elimination of systematic errors related to imperfect magnetic field gradients. Based on the results, the systematic bias for high resolution data mainly depended on SNR, but the influence of non-uniform gradients could also be seen. After denoising, the BSD method was able to further correct both the metrics and tractography of the diffusion tensor in the rat brain by taking into account the actual distribution of magnetic field gradients independent of the examined object and uniquely dependent on the scanner and sequence. This means that in vivo studies are also subject to this type of errors, which should be taken into account when processing such data.
Transcription factor roles in the local adaptation to temperature in the Andean Spiny Toad Rhinella spinulosa
Authors: Hinostroza Fernando , Araya-Duran Ingrid , Piñeiro Alejandro , Lobos Isabel , Pastenes Luis
Published: July 2024

Environmental temperature strongly influences the adaptation dynamics of amphibians, whose limited regulation capabilities render them susceptible to thermal oscillations. A central element of the adaptive strategies is the transcription factors (TFs), which act as master regulators that orchestrate stress responses, enabling species to navigate the fluctuations of their environment skillfully. Our study delves into the intricate relationship between TF expression and thermal adaptation mechanisms in the Rhinella spinulosa populations. We sought to elucidate the dynamic modulations of TF expression in prometamorphic and metamorphic tadpoles that inhabit two thermally contrasting environments (Catarpe and El Tatio Geyser, Chile) and which were exposed to two thermal treatments (25 °C vs. 20 °C). Our findings unravel an intriguing dichotomy in response strategies between these populations. First, results evidence the expression of 1374 transcription factors. Regarding the temperature shift, the Catarpe tadpoles show a multifaceted approach by up-regulating crucial TFs, including fosB, atf7, and the androgen receptor. These dynamic regulatory responses likely underpin the population’s ability to navigate thermal fluctuations effectively. In stark contrast, the El Tatio tadpoles exhibit a more targeted response, primarily up-regulating foxc1. This differential expression suggests a distinct focus on specific TFs to mitigate the effects of temperature variations. Our study contributes to understanding the molecular mechanisms governing thermal adaptation responses and highlights the resilience and adaptability of amphibians in the face of ever-changing environmental conditions.
Altered serum interleukin-17A and interleukin-23A levels may be associated with the pathophysiology and development of generalized anxiety disorder
Authors: Mamun-or-Rashid  , Roknuzzaman A. S. M. , Sarker Rapty , Nayem Jannatul , Bhuiyan Mohiuddin Ahmed , Islam Md. Rabiul , Al Mahmud Zobaer
Published: July 2024

In recent times, the pathogenesis of generalized anxiety disorder (GAD) and the influence of pro- and anti-inflammatory cytokines on it have garnered considerable interest. Cytokine research, especially Th-17 cytokine research on GAD patients, is limited. Here, we aim to assess the role of interleukin-17A (IL-17A) and interleukin-23A (IL-23A) in the pathophysiology and development of GAD. This investigation included 50 GAD patients and 38 age-sex-matched healthy controls (HCs). A psychiatrist diagnosed patients with GAD and assessed symptom severity using the DSM-5 and the GAD-7 scales. The serum concentrations of IL-17A and IL-23A were determined using commercially available ELISA kits. GAD patients exhibited elevated levels of IL-17A (77.14 ± 58.30 pg/ml) and IL-23A (644.90 ± 296.70 pg/ml) compared to HCs (43.50 ± 25.54 pg/ml and 334.40 ± 176.0 pg/ml). We observed a positive correlation between disease severity and cytokine changes (IL-23A: r = 0.359, p = 0.039; IL-17A: r = 0.397, p = 0.032). These findings indicate that IL-17A and IL-23A may be associated with the pathophysiology of GAD. ROC analysis revealed moderately higher AUC values (IL-23A: 0.824 and IL-17A: 0.710), demonstrating their potential to discriminate between patients and HCs. Also, the sensitivity values of both cytokines were relatively higher (IL-23A: 80.49% and IL-17A: 77.27%). According to the present findings, there may be an association between peripheral serum levels of IL-17A and IL-23A and the pathophysiology and development of GAD. These altered serum IL-17A and IL-23A levels may play a role in directing the early risk of developing GAD. We recommend further research to ascertain their exact role in the pathophysiology and their performance as risk assessment markers of GAD.
Profiling lipid mediators in serum from children with H1N1 influenza
Authors: Chen Weijun , Gu Yitao , Ma Yongjun , Dong Lele , Pan Liangxuan , Ji Chai , Guo Lanlan , Qi Lianxin , Zhang Yuanyuan , Gao Fei
Published: July 2024

Influenza A virus subtype H1N1 can cause severe acute respiratory distress syndrome and death in young children and elderly individuals. H1N1 initiates inflammatory responses that aim to contain and eliminate microbial invaders. Various lipid mediators (LMs) are biosynthesized and play a critical role in fighting viruses during inflammation; thus, by profiling the LMs in patients, researchers can obtain mechanistic insights into diseases, such as the pathways disrupted. To date, the relationship between molecular alterations in LMs and the pathogenesis of H1N1 influenza in children is poorly understood. Here, we employed a targeted liquid chromatography coupled with tandem mass spectrometry (LC‒MS/MS) to profile LMs in serum from children with H1N1 influenza (H1N1 children) and recovered children. We found that 22 LM species were altered in H1N1 children with mild symptoms. Analysis of the LM profiles of recovered children revealed a decrease in the levels of thromboxane B2 (TxB2) and thromboxane B3 (TxB3) and an increase in the levels of other 8 altered LM species associated with H1N1 influenza, including cytochrome P450 (CYP) enzyme-derived dihydroxyeicosatrienoic acids (DiHETrEs) and hydroxyeicosatetraenoic acids (HETEs) from arachidonic acid (AA), and epoxyoctadecamonoenoic acids (EpOMEs) from linoleic acid (LA). Taken together, the results of this study revealed that serum LMs change dynamically in H1N1 children with mild symptoms. The dramatically altered LMs in H1N1 children could serve as a basis for potential therapeutics or adjuvants against H1N1 influenza.
Impregnation of Silica Gel with Choline Chloride-MEA as an eco-friendly adsorbent for CO2 capture
Authors: Jahanbakhshi Maryam , Ghaemi Ahad , Helmi Maryam
Published: July 2024

Deep eutectic solvents (DES) are a generation of ionic liquids that benefit from low cost, good stability, and environmental-friendly features. In this research, a porous silica gel was impregnated with a eutectic Choline Chloride-Monoethanolamine solvent (ChCl-MEA) to greatly improve its CO2 capture performance. In the impregnation, the weight percentages of ChCl-MEA were used in the range of 10–60 wt% at a temperature of 25 °C. The effect of ChCl-MEA loading on the structural properties of the DES-modified silica samples was studied by BET, FTIR, and TGA analyses. Investigation of the CO2 adsorption performance at different operational conditions showed that the modified silica gel with 50 wt% ChCl-MEA (Silica-CM50) presents the highest CO2 capture capacity of 89.32 mg/g. In the kinetic modeling, the fractional order model with a correlation coefficient of 0.998 resulted in the best fit with the experimental data. In addition, the isotherm data for Silica-CM50 were well-fitted with the Dual site Langmuir isotherm model with a correlation coefficient of 0.999, representing two distinct sites for the adsorption process. Moreover, the thermodynamic parameters including Enthalpy, Entropy, and Gibbs free energy at 25 °C were obtained to be − 2.770, − 0.005 and − 1.162, respectively. The results showed the exothermic, spontaneous and feasibility of the adsorption process.
Face-centered cubic carbon as a fourth basic carbon allotrope with properties of intrinsic semiconductors and ultra-wide bandgap
Authors: Konyashin Igor , Muydinov Ruslan , Cammarata Antonio , Bondarev Andrey , Rusu Marin , Koliogiorgos Athanasios , Polcar Tomáš , Twitchen Daniel , Colard Pierre-Olivier , Szyszka Bernd , Palmer Nicola
Published: July 2024

Carbon is considered to exist in three basic forms: diamond, graphite/graphene/fullerenes, and carbyne, which differ in a type of atomic orbitals hybridization. Since several decades the existence of the fourth basic carbon allotropic form with the face-centered cubic (fcc) crystal lattice has been a matter of discussion despite clear evidence for its laboratory synthesis and presence in nature. Here, we obtain this carbon allotrope in form of epitaxial films on diamond in a quantity sufficient to perform their comprehensive studies. The carbon material has an fcc crystal structure, shows a negative electron affinity, and is characterized by a peculiar hybridization of the valence atomic orbitals. Its bandgap (~6 eV) is typical for insulators, whereas the noticeable electrical conductivity (~0.1 S m−1) increases with temperature, which is typical for semiconductors. Ab initio calculations explain this apparent contradiction by noncovalent sharing p-electrons present in the uncommon valence band structure comprising an intraband gap. This carbon allotrope can create a new pathway to ‘carbon electronics’ as the first intrinsic semiconductor with an ultra-wide bandgap.
High-dimensional mapping of human CEACAM1 expression on immune cells and association with melanoma drug resistance
Authors: Huang Yu-Hwa , Yoon Charles H. , Gandhi Amit , Hanley Thomas , Castrillon Carlos , Kondo Yasuyuki , Lin Xi , Kim Walter , Yang Chao , Driouchi Amine , Carroll Michael , Gray-Owen Scott D. , Wesemann Duane R. , Drake Charles G. , Bertagnolli Monica M. , Beauchemin Nicole , Blumberg Richard S.
Published: July 2024

Background

Human carcinoembryonic antigen cell adhesion molecule 1 (CEACAM1) is an inhibitory cell surface protein that functions through homophilic and heterophilic ligand binding. Its expression on immune cells in human tumors is poorly understood.

Methods

An antibody that distinguishes human CEACAM1 from other highly related CEACAM family members was labeled with 159Tb and inserted into a panel of antibodies that included specificity for programmed cell death protein 1 (PD1) and PD-L1, which are targets of immunotherapy, to gain a data-driven immune cell atlas using cytometry by time-of-flight (CyTOF). A detailed inventory of CEACAM1, PD1, and PD-L1 expression on immune cells in metastatic lesions to lymph node or soft tissues and peripheral blood samples from patients with treatment-naive and -resistant melanoma as well as peripheral blood samples from healthy controls was performed.

Results

CEACAM1 is absent or at low levels on healthy circulating immune cells but is increased on immune cells in peripheral blood and tumors of melanoma patients. The majority of circulating PD1-positive NK cells, innate T cells, B cells, monocytic cells, dendritic cells, and CD4+ T cells in the peripheral circulation of treatment-resistant disease co-express CEACAM1 and are demonstrable as discrete populations. CEACAM1 is present on distinct types of cells that are unique to the tumor microenvironment and exhibit expression levels that are highest in treatment resistance; this includes tumor-infiltrating CD8+ T cells.

Conclusions

To the best of our knowledge, this work represents the first comprehensive atlas of CEACAM1 expression on immune cells in a human tumor and reveals an important correlation with treatment-resistant disease. These studies suggest that agents targeting CEACAM1 may represent appropriate partners for PD1-related pathway therapies.
Analysis of anthropometric outcomes in Indian children during the COVID-19 pandemic using National Family Health Survey data
Authors: Summan Amit , Nandi Arindam , Laxminarayan Ramanan
Published: July 2024

Background

Disruptions in food, health, and economic systems during the COVID-19 pandemic may have adversely affected child health. There is currently limited research on the potential effects of the COVID-19 pandemic on stunting, wasting, and underweight status of young children.

Methods

We examine the short-term associations between the pandemic and anthropometric outcomes of under-5 children (n = 232,920) in India, using data from the National Family Health Survey (2019–2021). Children surveyed after March 2020 are considered as the post-COVID group, while those surveyed earlier are considered as pre-COVID. Potential biases arising from differences in socioeconomic characteristics of the two groups are mitigated using propensity score matching methods.

Results

Post-COVID children surveyed in 2020 and 2021 have 1.2% higher underweight rates, 1.2% lower wasting rates, 0.1 lower height-for-age z-scores (HAZ), and 0.04 lower weight-for-height z-scores as compared with matched pre-COVID children. Post-COVID children surveyed in 2020 have 1.6%, 4.6%, and 2.4% higher stunting, underweight, and wasting rates, respectively, and 0.07 lower HAZ, as compared with matched pre-COVID children. Reductions in nutritional status are largest among children from households in the poorest wealth quintiles.

Conclusions

These findings indicate a trend towards a recovery in child anthropometric outcomes in 2021 after the initial post-pandemic reductions. The resilience of health and food systems to shocks such as COVID-19 should be strengthened while immediate investments are required to decrease child malnutrition and improve broader child health outcomes.
Elucidating ultranarrow 2F7/2 to 2F5/2 absorption in ytterbium(iii) complexes
Authors: Li Barry Y. , Dickerson Claire E. , Shin Ashley J. , Zhao Changling , Shen Yi , He Yongjia , Diaconescu Paula L. , Alexandrova Anastassia N. , Caram Justin R.
Published: July 2024

Achieving ultranarrow absorption linewidths in the condensed phase enables optical state preparation of specific non-thermal states, a prerequisite for quantum-enabled technologies.
Microfluidic measurement of intracellular mRNA with a molecular beacon probe towards point-of-care radiation triage
Authors: Meng Xin , Wen Kechun , Zhao Jingyang , Han Yaru , Ghandhi Shanaz A. , Kaur Salan P. , Brenner David J. , Turner Helen C. , Amundson Sally A. , Lin Qiao
Published: July 2024

We designed molecular beacons targeting BAX mRNA for intracellular fluorescence measurement.
Designing solution-processed thermally activated delayed fluorescence emitters via introducing bulky steric hindrance groups for pure red OLEDs
Authors: Li Shuo , Chen Liang , Li Maoqiu , Zhang Taoyi , Yan Shouke , Ren Zhongjie
Published: July 2024

We introduced bulky spiro-fluorene groups into a newly designed pure red TADF molecule to reduce the triplet exciton quenching caused by intermolecular π–π stacking.
Integration of a bulky adamantane unit with 9-phenyl-9H-3,9′-bicarbazole: a novel host design for solution-processed narrowband TADF-OLEDs
Authors: Kwak Haeun , Peethani Nagaraju , Park Su Hong , Kwon Na Yeon , Park Jin Young , Kang Min Ji , Park Chae Yeong , Kim Ha Yeon , Hong Chang Seop , Park Sungnam , Cho Min Ju , Choi Dong Hoon
Published: July 2024

A p-type host, CzCzPh-mAd, incorporating a bulky and rigid adamantane group, demonstrates promising performance stability for high-efficiency solution-processed OLEDs.
Quinacridone dyes: versatile molecules and materials for photo- and photoelectrochemical processes
Authors: Rossin Elena , Yang Yunshuo , Chirico Martina , Rossi Greta , Galloni Pierluca , Sartorel Andrea
Published: July 2024

We discuss the versatility of quinacridone pigment in photocatalysis, embracing water splitting, carbon dioxide reduction and organic synthesis. Applications include homogeneous catalysis, nanoparticles, covalent organic frameworks, photoelectrodes.
A device to measure apparent swelling pressure of compacted bentonite using extremely thin specimen
Authors: Wang Hailong
Published: July 2024

As a candidate material proposed for the geological disposal of the high level radioactive waste, bentonite has been studied extensively in terms of its engineering properties. One of the properties is the pressure generated during wetting compacted bentonite under rigorously confined condition. This pressure is designated apparent swelling pressure (ps) herein. On the other hand, due to the extremely low hydraulic conductivity (e.g. 10-9-10-14 m/s) of compacted bentonite, it is often very time consuming to measure ps. For instance, test duration is typically 1-2 month for a specimen with thickness (hsp) of 20 mm, and 1-2 weeks for hsp= 10 mm. Though testing duration can be reduced by using thinner specimens, it becomes difficult to control measurement accuracy. Recently, the author reported a series of datasets obtained with newly developed testing method using hsp= 2 mm specimens to measure ps, by which testing duration was reduced to 1-2 days and data repeatability was also extraordinarily good. In this paper, the author made further developments on such testing techniques and introduced a device to measure ps for hsp= 0.4 mm specimen, by which testing duration can be reduced to 1-2 hours. The ps measured by this device on a bentonite was compared with previous database, which implies that data repeatability is very good in generally, though the data scattering is observed for hsp=0.4 mm specimens.
Impact of specimen preparation on erosion and post-erosion response of gap-graded soils
Authors: Mousavi Meysam , Mehdizadeh Amirhassan , Disfani Mahdi M.
Published: July 2024

Internal erosion is a major threat to the safety and operation of water management structures. Recent failures of embankment dams reported in Australia, Canada, and the US are fresh reminders of the importance of this ongoing issue. Suffusion, the focus of this paper, is one of the main modes of internal erosion occurring in internally unstable soils. It initiates internally, continues slowly with no visible signs, and leads to complete failure if not detected early. Despite recent advances in understanding the influence of suffusion on the mechanical behaviour of internally unstable soils through laboratory investigations, the impact of sample preparation techniques on the soil response during erosion and afterwards is yet to be fully undrstood. When it comes to laboratory investigation of remoulded soils, it has been understood that soil specimens prepared by different techniques show different characteristics and soil fabrics. This research studied the influence of sample preparation methods on the erosion of non-plastic fine particles in internally unstable soils and their mechanical consequences. Soil samples with two gradations, on the borderline of stable and unstable and one fully unstable, were prepared using moist-tamping and wet pluviation techniques and were subjected to a two-hour downward seepage. The erosion progress and pre- and post-erosion drained mechanical behaviour of samples were investigated. Tests result showed a difference in the erodibility of fine particles for the sample on the borderline of internal stability prepared by different techniques, but similar mechanical behaviours for both gradations.
Evolution of excess pore water pressure in undrained claystructure interface shear tests
Authors: Martinez Alejandro , Stutz Hans Henning
Published: July 2024

Recent studies focused on the shear behaviour of clay-structure interfaces have shown the importance of the shearing rate on the strength of these interfaces. In normally-consolidated clays, increasing the shearing rate results in a decrease in the interface strength, while the trend is opposite in heavily overconsolidated clays. While analytical and empirical interpretation methods indicate that the generation of shear-induced excess pore pressures are responsible for theaforementioned trends, experiments with pore water pressure measurements at the clay-structure interface are rare. In this paper, we first describe a modified interface shear box testing setup that is equipped with a pore water pressure sensor. For this equipment, the fully rough structural surface was manufactured with a port at the centre of the clay-surface interface to measure the pore water pressure. We present the results of undrained clay-structure interface tests on normally consolidated (NC) and overconsolidated (OC) specimens of kaolin clay. The results agree with the expectations, where the NC specimens generate excess pore pressures with greater magnitudes and heavily OC specimens generate negative excess pore pressures. Measurements of the pore water pressures allow calculating vertical effective stresses, which can be used to investigate the effective stress paths followed by the clay-structure interface during the tests. This paper also provides a comparison of the measured values of beta and adhesion factors with previously published results and relationships used for the design of deep foundations.
Deformations of bentonite-sand mixture without lateral confining pressure subject to high suctions changing
Authors: Nishimura Tomoyoshi
Published: July 2024

Generation of electricity in nuclear power plants have supplied further energy to society in the world, and remain arising of radioactive waste as results of performance industry with activity. In fact, all of radioactive waste encourage some categories types as following; two most important points are high-level waste (HLW) and low- and intermediate-level waste (LLW). To end disposal completely, every country operated Nuclear Energy plant foresees further deep geological repository. This study conducted out measurement of deformations due to changing suction, which were volume change, axial strains and radial strains. Used triaxial compression apparatus was improved to be possible controlling suction for air flow circulation, and measured both axial and radial strains and variations of mass under drying-wetting cyclic in suction. Required suction rage is from 2.8 MPa to 296 MPa, and it corresponds to from 98.0 % to 11.0 % in relative humidity. Axial strains and radial strains for all of specimens have described obviously the shrinkage phenomena due to drying and wetting cyclic process regard to suction potential, and bentonite-sand mixture specimens are statically compacted. Axial strains compare that is larger than radial strains regard to all applied suctions. Subsequently, changing of void ratio was classified into two categories, which one was elastic components and other one was plastic component, and elastic component in void ratio was remaining larger than plastic component for high suction ranges.
Sand liquefaction in simple shear tests
Authors: Lentini Valentina , Castelli Francesco , Di Venti Alessandra
Published: July 2024

Liquefaction is a phenomenon marked by a rapid loss of soil strength and stiffness, which generally occurs in loose saturated sandy deposit during earthquake because of the generation of excess pore water pressure. Several experimental researches concluded that liquefied soil behaves as a fluid during ground movement, but after the earthquake motion ceases, due to the dissipation of excess pore water pressure, the liquefied soil recovers its initial stiffness and returns to behave as a solid. Liquefaction resistance of sandy soil can be studied by means of Cyclic Simple Shear (CSS) test or Cyclic Triaxial (CTX) tests. While CTX tests are widely used in liquefaction studies due to their simplicity, CSS tests are more representative of stress conditions produced during an earthquake by simulating the continuous rotation of the principal stress axes. In this research the preliminary results of CSS tests carried out with confining rings on the sandy samples retrieved in the South of Sicily are reported. The apparatus is described in detail. All samples used were obtained from the same type of Italian sand by using same preparation method to minimize the number of factors influencing the results. Moreover, all tests were conducted by a single operator. All experimental results are reported in the plane cyclic resistance ratio (CRR) and number of cycles where liquefaction occurs (Nliq) in order to assess the liquefaction phenomenon.
An automated system for determining soil parameters: Case study
Authors: Marzouk Islam , Oberhollenzer Simon , Tschuchnigg Franz
Published: July 2024

The success of numerical analysis depends on several factors. One of the keys factors is the accurate determination of constitutive model parameters. Determining these parameters from in-situ tests has several advantages compared to laboratory tests, from lower costs to minimal disturbance of the soil. However, it is not possible to derive soil parameters directly from in-situ tests results, since correlations are required. The literature offers a wide range of correlations which increases the uncertainty during interpretation. The ongoing research project APD (Automated Parameter Determination) investigates the possibilities of automated parameter identification from in-situ tests using a graph-based approach. In the present paper, existing correlations – developed for cone penetration tests - are validated by comparing their output to laboratory results. The Norwegian GeoTest Sites (NGTS) infrastructure project consists of five tests sites in different soils in Norway. The data from the soft clay site located in Onsoy, south-eastern Norway was used in the validation process. A web-based application “Datamap” that has been developed to capture, organize, and classify geotechnical research data has been used to obtain in-situ and laboratory tests data. The further validation of existing correlations to derive accurate constitutive parameters from in-situ tests is part of ongoing research.
A procedure to analyze a one dimensional compression test
Authors: Díaz-Rodríguez Jorge Abraham
Published: July 2024

The subsoil of Mexico City (SMC) is highly compressible when loads are applied. This feature is associated with many uncertainties and complex issues during foundation design processes. The compressibility of the SMC has been investigated since the 40s by using oedometer tests in most cases. However, the importance of the results in interpreting compression test data requires a systematic method of determining the end of consolidation (EOC) under a load increment. This paper offers an alternative view to analyze a one-dimensional compression test, decomposing the time-compression curve into two curves, one due to consolidation and another due to volumetric creep, using numerical processing. This approach has several advantages: (1) Data reduction allows us to know the contribution of consolidation and volumetric creep at any time and for each load increment. (2) a systematic method of determining the end-of-consolidation (EOC) under a load increment, and (3) long-term strains (settlements) can be estimated at any time. Finally, an example of the results obtained using the suggested method is presented.
Non-invasive characterization of particle morphology of calcareous sands from São Tomé & Príncipe
Authors: Beemer Ryan , Fonseca Joana , Shaw Jeremy
Published: July 2024

Calcareous sands of biogenic origin are widely spread throughout the world’s seabed. They are the foundation soils for many offshore geotechnical structures, and, in addition, onshore uses of this material are becoming more significant with the growing demand of backfill material for transport infrastructure. These sands comprise the remains of marine organisms such as shells and tests, and the grains can vary from platy to hollow thin-walled forms with highly angular features. Geotechnical design on calcareous sands is challenging owing to the many uncertainties related to their microscale properties. This study uses non-invasive X-ray micro-computed tomography (μCT) and advanced three-dimensional (3D) image analysis techniques to quantify the morphology of bioclastic calcareous sands from São Tomé & Príncipe. The statistics of particle shape parameters of the São Tomé sand are compared to that of the previously studied Ledge Point sand. In spite of an order of magnitude difference in particle size, São Tomé and Ledge Point sands are markedly similar and, as seen in other calcareous sand, São Tomé shows a strong correlation in 3D sphericity and convexity. The results presented here help to better understand the mechanisms of grain interlocking, and the role of intra-granular void ratio on the mechanical behaviour of calcareous sands from different parts of the world.
Natural state parameter for sand
Authors: Dołżyk-Szypcio Katarzyna
Published: July 2024

Based on the frictional state concept, the natural state parameter for sands is defined as an extension of the state parameter defined by Been and Jefferies. The proposed definition of the natural state parameter is the sum of the distance between the normalised difference of the current stress ratio and the critical frictional stress ratio and the difference between the current and critical frictional state void ratio for the same mean principal stress. Therefore, it combines the difference between the current and critical frictional state in the q ‒ p’ and e ‒ p’ planes and can be treated as an extension of Been and Jefferies’ definition of the state parameter in the e ‒ p’ plane. The results of drained triaxial compression tests for Toyoura sand and Dog’s Bay sand, presented in the literature, are analysed. The values of the natural state parameter at failure for these sands are equal to zero. Therefore, the critical state in the q ‒ p’ and e ‒ p’ planes can be determined by analysing the conditions at failure. At failure, the deformations of the samples are almost homogeneous, and the stresses and deformations (void ratios) can be correctly determined. Additionally, the critical frictional state and critical state are very similar for these sands. The relationship between the dilatancy and the state parameter at failure, similar to that given by Been and Jefferies, was obtained directly by using the frictional state concept and the proposed definition of the natural state parameter. The natural state parameter, like the state parameter, can be used for modelling of sands in the future.
Using shear modulus to predict the bearing capacity of strip foundations on sand
Authors: Murison Ruan Andrew , Heymann Gerhard
Published: July 2024

This paper reports results of a study to predict load-settlement behaviour of strip foundations on a dry uncemented sand using only soil stiffness data, under both working loads and extreme loads. This involved predicting the strength of a foundation system without using any strength parameters. A non-linear stepwise load-settlement prediction algorithm was utilised, which used the small-strain shear modulus of layers below the footing, a suitable stiffness modulus reduction curve and elasticity theory. The algorithm was adapted to predict the ultimate bearing capacity, as well as to construct astress-settlement curve and determine the bearing pressure experienced beneath a foundation at any particular settlement. The method was evaluated using two different sets of modulus reduction curves, for small-scale model foundations on loose, medium dense and dense sand. Model tests were conducted at 1g. Particle Image Velocimetry (PIV) was used to observe strains within the soil during loading. These strains were used to calculate the shear modulus of discrete layers throughout loading and back-estimate the layer small-strain shear moduli. Additionally, the mode of shear failure for each test at ultimate bearing capacity was observed using PIV. Modulus reduction curves that initially degrade shear modulus rapidly beyond the elastic threshold strain (0.001%) gave superior predictions under the given conditions. Using such curves, ultimate bearing capacity predictions produced errors of 0.4% to 10.8%. Using the same input parameters, stresssettlement predictions were of satisfactory accuracy over the entire settlement range.
Isotropic compression simulation of kaolinite using coarse-grained molecular dynamics
Authors: Nakamichi Yohei , O’Sullivan Catherine , Angioletti-Uberti Stefano , Tangney Paul , Bandera Sara
Published: July 2024

It is now viable to use coarse-grained molecular dynamics (CGMD) to model interacting clay particles in simulations of soil mechanics element tests. In CGMD, particle interactions are described by the Gay-Berne (GB) potential, which can approximate the potential energy between clay particles as a function of their separation and relative orientations; however, a previous study identified a significant shortcoming of the GB potential, which is that it lacks a local maximum called the “energy barrier” that the true interaction possesses at very close range. In this study, we propose a modified GB potential which can capture the energy barrier at and we use this new potential function to simulate the clay mineral kaolinite under isotropic compression. Our simulations show that the energy barrier is a crucial ingredient required to reproduce the elastoplastic behaviour observed in laboratory tests upon unloading from an isotropic normally consolidated state. Our data show that the difference in mechanical behaviour between normally consolidated clay and overconsolidated clay can be explained by the fact that, during the initial loading, some pairs of interacting particles surmount the energy barrier so that they then experience a large attractive force. Effectively, these particles become bounded and do not separate when the stress applied to the sample is released. The response of overconsolidated clay to applied stress is stiffer than that of normally consolidated clay because a larger proportion of the clay particle interactions exist in this bonded state.
Soft-rigid granular mixtures: Role of particle shape and rolling resistance in response under compressive loads
Authors: Alam Mehdi , Das Arghya , Disfani Mahdi M.
Published: July 2024

Mixtures of recycled tyre aggregates and common granular geo-material such as gravel and sand have been widely used for various applications in geotechnical engineering, such as backfill, lightweight construction geomaterial and pavement subbase layers. The mechanical properties and characteristics of various soft-rigid granular blends has been extensively studied in the past. The main objective of these studies is to determine suitable mix designs for different applications and provide a better understanding of material response under applied loads. Experimental and numerical studies indicate the paramount importance of particle interaction at the microscale on the response of the soft-rigid granular mixtures at the macro scale. The stark contrast in stiffness (or flexibility) of soft tyre particles to rigid sand or gravel particles, means that in the soft-rigid mixtures under shearing or compressive loads, the deformation of soft tyre particles and continuous change of shape and contact area and hence constant evolution of frictional resistance plays an important role in the behaviour of these blends. In the present research mixtures of gravel and tyre particles in a range of volume ratios and size ratios were modelled using DEM (discrete element method) and calibrated to match one-dimensional compressibility experimental data obtained by the team. The effect of the shape of soft particles on the compressive response of soft-rigid granular mixtures is studied through rolling resistance in DEM. The role of rolling friction is studied in detail. Rolling resistance is found to be an important parameter to simulate the behaviour of the particle shape of these mixtures. Microscopic studies like spin analysis and share of contact force is performed to understand the observed response better. However, the increase in rolling resistance value beyond a calibrated value is found to have little impact on the macroscopic behaviour of these mixes.
Clay micromechanics: Mapping the future of particle-scale modelling of clay
Authors: Pagano Arianna Gea , Alonso-Marroquin Fernando , Ioannidou Katerina , Radjai Farhang , O’Sullivan Catherine
Published: July 2024

Geotechnical engineers need to predict the macroscopic behaviour of clays in terms of strength, stiffness, and permeability and the variation in these properties during deformation. Engineers also need to predict the influence of environmental variables (temperature, pressure, pore-fluid chemistry) on these engineering properties. Particle-based methods, which explicitly model individual clay platelets and their interactions, can help identify the fundamental mechanisms that govern the engineering behaviour. Virtual samples can be created, and simulations can consider application of mechanical loading or change in the environmental conditions to generate data on particle kinematics and interparticle interactions. Particlebased models can be used to simulate stress and strain paths that are not easy to reproduce in physical experiments. This approach to simulation also enables parametric studies to understand the sensitivity of the overall behaviour to various particle characteristics and the nature of the particle interactions. This contribution provides a review of the state-of-theart of existing particle-based models for clays, namely Discrete Element Method (DEM), Monte Carlo method (MC), and Molecular Dynamics (MD). The technical challenges, advantages, and disadvantages of each method for the simulation of clays are presented and discussed, together with the technical developments we would like to see over the next decade to realize the full potential of these modelling tools.
Discrete modelling of the mechanical response of Cuxhaven sand under shear and oedometric conditions using the rolling resistance contact model
Authors: Uday Anjali , Peña-Olarte Andrés Alfonso , Wang Yuting
Published: July 2024

The Distinct element method (DEM) is a promising approach to model the microscopic behaviour of granular materials, but the capability of the simulations to reproduce the mechanical response of real granular materials depends strongly on the contact model parameters utilized. The present study focuses on the calibration and validation of the rolling resistance linear model parameters for Cuxhaven sand based on the experimental results from triaxial and oedometer tests. A sensitivity analysis was conducted to explore the influence of contact model parameters on the sample preparation and the shear stage of triaxial tests. The influence of parameters like rolling resistance friction coefficient, inter-particle friction coefficient, effective modulus, and normal-to-shear stiffness ratio were investigated. For calibration of the DEM model, the input parameters were selected such that the simulations reproduce the macro mechanical characteristics like dilation angle, peak stress, and stiffness. The calibrated parameters were then validated by simulating a one-dimensional compression test. The results are in good agreement with the experiments, which proves the suitability of the calibrated parameters. In addition, the validated parameters were applied to investigate the mechanical behaviour including the evolution of contact force chains, non-coaxiality of principal stress and strain rate, and sample inhomogeneity during a simple shear test.
Behaviour of saturated sand under cyclic loading: Model approach with experimental validation
Authors: Velayudham Jotheeshwar , Airey David , Mohammadi Amirabbas , Ghorbhani Javad
Published: July 2024

This study presents a comparison between triaxial test results and constitutive model simulations for saturated sand subjected to a wide range of stress, relative density and both monotonic and cyclic loadings. This is a preliminary part of a project which is focussed on developing models for the behaviour of unsaturated soils under cyclic loading. There are currently limited experimental data of the cyclic behaviour of unsaturated soils due in part to the difficulty of controlling stress state, degree of initial saturation and uniformity of samples in experiments and their interpretation is challenging due to the mathematical complexity in constitutive models. This study attempts to bridge the abovementioned gap by creating an experimentally validated constitutive model for dynamic loading on saturated sand and then to extend this for unsaturated sands. The paper reports results from a series of monotonic triaxial tests and cyclic triaxial tests on saturated sand. Specimens of 100mm diameter, 200mm height and 54mm diameter, 110mm height have been prepared with different void ratios. These samples have been subjected to a wide range of deviatoric stress in both monotonic and cyclic tests. The results from these tests on saturated Sydney sand are presented and used to demonstrate the ability of the constitutive model. As the constitutive model has been developed for variable saturation demonstration of its success with saturated sand for which considerable data is available is the first stage in simulating the cyclic behaviour of the unsaturated sand.