bluuebunny/crossref_metadata_2025 huggingface dataset:
Post-COVID-19 Symptoms and Heart Disease: Incidence, Prognostic Factors, Outcomes and Vaccination: Results from a Multi-Center International Prospective Registry (HOPE 2)
Authors: Núñez-Gil Ivan J. , Feltes Gisela , Viana-Llamas María C. , Raposeiras-Roubin Sergio , Romero Rodolfo , Alfonso-Rodríguez Emilio , Uribarri Aitor , Santoro Francesco , Becerra-Muñoz Víctor , Pepe Martino , Castro-Mejía Alex F. , Signes-Costa Jaime , Gonzalez Adelina , Marín Francisco , Lopez-País Javier , Cerrato Enrico , Vázquez-Cancela Olalla , Espejo-Paeres Carolina , López Masjuan Álvaro , Velicki Lazar , El-Battrawy Ibrahim , Ramakrishna Harish , Fernandez-Ortiz Antonio , Perez-Villacastín Julián
Published: January 2023

Background: Heart disease is linked to worse acute outcomes after coronavirus disease 2019 (COVID-19), although long-term outcomes and prognostic factor data are lacking. We aim to characterize the outcomes and the impact of underlying heart diseases after surviving COVID-19 hospitalization. Methods: We conducted an analysis of the prospective registry HOPE-2 (Health Outcome Predictive Evaluation for COVID-19-2, NCT04778020). We selected patients discharged alive and considered the primary end-point all-cause mortality during follow-up. As secondary main end-points, we included any readmission or any post-COVID-19 symptom. Clinical features and follow-up events are compared between those with and without cardiovascular disease. Factors with p < 0.05 in the univariate analysis were entered into the multivariate analysis to determine independent prognostic factors. Results: HOPE-2 closed on 31 December 2021, with 9299 patients hospitalized with COVID-19, and 1805 died during this acute phase. Finally, 7014 patients with heart disease data were included in the present analysis, from 56 centers in 8 countries. Heart disease (+) patients were older (73 vs. 58 years old), more frequently male (63 vs. 56%), had more comorbidities than their counterparts, and suffered more frequently from post-COVID-19 complications and higher mortality (OR heart disease: 2.63, 95% CI: 1.81–3.84). Vaccination was found to be an independent protector factor (HR all-cause death: 0.09; 95% CI: 0.04–0.19). Conclusions: After surviving the acute phase, patients with underlying heart disease continue to present a more complex clinical profile and worse outcomes including increased mortality. The COVID-19 vaccine could benefit survival in patients with heart disease during follow-up.
Local Tendon Transfers for Chronic Ruptures of the Achilles Tendon: A Systematic Review
Authors: Maffulli Nicola , Ziello Salvatore , Maisto Gianluca , Migliorini Filippo , Oliva Francesco
Published: January 2023

Introduction: A rupture of the Achilles tendon with a delay in diagnosis or treatment for more than 6 weeks is considered a chronic tear. Local tendon transfer procedures can be used in chronic Achilles tendon ruptures. This study evaluated the outcome, return to sport, and complications of local tendon transfer in patients with chronic Achilles tendon rupture. Material and methods: The present study was conducted according to the PRISMA 2020 guidelines. PubMed, Google Scholar, Embase, and Web of Science databases were accessed in November 2022. Results: Data were retrieved from 23 articles (463 patients, mean age 50.9 ± 13.5 years). The mean duration of the follow-up was 58.3 ± 76.8 months. The VAS improved by 1.8/10 (p = 0.4), the AOFAS by 33.4/100 (p < 0.0001), and the ATRS by 32.5/100 (p = 0.0001) points. Patients were able to return to sport after a mean of 19.6 ± 16.4 weeks. A total of 79% of patients were able to return to their previous activities. The rate of complications was 13.3%. Conclusions: The use of local tendon transfer for chronic Achilles tendon ruptures using the FHL or PB tendon resulted in good clinical outcomes and a reliable return to daily activities and sports. The rate of complications reflects the chronicity of the condition and the technical complexity of the procedure. Level of evidence: IV.
KRAS Mutations in Solid Tumors: Characteristics, Current Therapeutic Strategy, and Potential Treatment Exploration
Authors: Yang Yunkai , Zhang Huan , Huang Shanshan , Chu Qian
Published: January 2023

Kristen rat sarcoma (KRAS) gene is one of the most common mutated oncogenes in solid tumors. Yet, KRAS inhibitors did not follow suit with the development of targeted therapy, for the structure of KRAS has been considered as being implausible to target for decades. Chemotherapy was the initial recommended therapy for KRAS-mutant cancer patients, which was then replaced by or combined with immunotherapy. KRAS G12C inhibitors became the most recent breakthrough in targeted therapy, with Sotorasib being approved by the Food and Drug Administration (FDA) based on its significant efficacy in multiple clinical studies. However, the subtypes of the KRAS mutations are complex, and the development of inhibitors targeting non-G12C subtypes is still at a relatively early stage. In addition, the monotherapy of KRAS inhibitors has accumulated possible resistance, acquiring the exploration of combination therapies or next-generation KRAS inhibitors. Thus, other non-target, conventional therapies have also been considered as being promising. Here in this review, we went through the characteristics of KRAS mutations in cancer patients, and the prognostic effect that it poses on different therapies and advanced therapeutic strategy, as well as cutting-edge research on the mechanisms of drug resistance, tumor development, and the immune microenvironment.
Negative Pressure Wound Therapy with Instillation: Analysis of the Rinsing Fluid as a Monitoring Tool and Approach to the Inflammatory Process: A Pilot Study
Authors: Biermann Niklas , Wallner Stefan , Martini Teresa , Spoerl Steffen , Prantl Lukas , Taeger Christian D.
Published: January 2023

Background: Negative pressure wound therapy with instillation (NPWTi) is an established wound conditioning tool. Previous investigations discovered that the rinsing fluid is a suitable monitoring tool containing various cells and cytokines. Methods: The aim of this pilot study was to analyze rinsing fluid samples from patients treated with NPWTi and link them to the clinical course, including microbiological contamination. In 31 consecutive patients with acute and chronic wounds, laboratory analysis was performed to evaluate IL-6, IL-8, bFGF, Tnf-a, and VEGF. Results: IL-6 showed a significant increase to 1540 pg/mL on day two and 860 pg/mL on day four (p = 0.01 and p = 0.04, resp.). IL-8 steadily increased from a median of 2370 pg/mL to a maximum of 19,400 pg/mL on day three (p = 0.01). The median bFGF showed a steady decline from 22 pg/mL to 10 pg/m (p = 0.35) on day three. The median Tnf-a increased from 11 pg/mL to 44 pg/mL (p = 001). The median VEGF values fluctuated but showed an overall increase from 35 pg/mL to 250 pg/mL (p = 0.07). Regarding IL-8, diabetic and non-diabetic patients both showed a gradual increase with non-significant higher median values for the diabetics. The subgroup analysis of IL-6 showed increasing and higher values in cases with bacterial superinfections (p = 0.07). Conclusion: We were able to use an established wound conditioning tool to gather important information about the inflammatory response during NPWTi treatment. Cytokine and cell courses were mostly consistent with the literature, especially in diabetic patients, and should be further investigated.
Diagnostic Efficacy of Serum Asialo α1-Acid Glycoprotein Levels for Advanced Liver Fibrosis and Cirrhosis in Patients with Chronic Hepatitis B Compared to That in Healthy Subjects: A Prospective Study
Authors: Lee Yoonseok , Bae Seryun , Kim Ji Hoon , Kwak Minjung , Jeon So Yeon , Kim Taehyung , Yim Sun Young , Lee Young-Sun , Jung Young Kul , Seo Yeon Seok , Yim Hyung Joon , Yeon Jong Eun , Byun Kwan Soo
Published: January 2023

Background: Serum asialo α1-acid gycoprotein (AsAGP) is a novel biomarker specific to liver fibrosis. Aim: To evaluate the diagnostic efficacy of serum AsAGP levels in classifying the severity of liver fibrosis and differentiating liver cirrhosis (LC) in patients with chronic hepatitis B (CHB) from healthy controls. Methods: Overall, 206 subjects were prospectively enrolled. LC was diagnosed based on liver stiffness levels (>11 kPa) measured using transient elastography. Serum AsAGP levels were measured using an antibody-lectin sandwich immunoassay. We investigated the diagnostic performance by comparing serum AsAGP levels among healthy control, CHB, and CHB with LC groups. Sensitivity, specificity, and optimal AsAGP cut-off values were also calculated. Results: Serum AsAGP levels were significantly different between healthy controls, CHB patients, and CHB patients with LC (1.04 ± 0.31 µg/mL, 1.12 ± 0.34 µg/mL, 1.51 ± 0.43 µg/mL respectively; p < 0.001). Serum AsAGP levels positively correlated with liver stiffness (r = 0.46, p < 0.001). AUROC of healthy control versus CHB with LC was 0.821 (p < 0.001, optimal cut-off 1.036 µg/mL). AUROC of healthy control versus CHB was 0.624 (p = 0.049, optimal cut-off level 0.934 µg/mL). AUROC of CHB versus CHB with LC was 0.765, (p < 0.001, optimal cut-off 1.260 µg/mL). Conclusions: Serum AsAGP levels in CHB patients with LC were significantly higher than those in healthy controls and CHB patients. AsAGP levels showed good diagnostic performance in predicting advanced fibrosis and cirrhosis, which suggests a potential role as a biomarker for predicting the progression of liver disease in CHB.
Reliability and Validity of Non-Instrumental Clinical Assessments for Adults with Oropharyngeal Dysphagia: A Systematic Review
Authors: Cordier Reinie , Speyer Renée , Martinez Matthew , Parsons Lauren
Published: January 2023

This systematic review on non-instrumental clinical assessment in adult oropharyngeal dysphagia (OD) provides an overview of published measures with reported reliability and validity. In alignment with PRISMA, four databases (CINAHL, Embase, PsycINFO, and PubMed) were searched, resulting in a total of 16 measures and 32 psychometric studies included. The included measures assessed any aspect of swallowing, consisted of at least one specific subscale relating to swallowing, were developed by clinical observation, targeted adults, and were developed in English. The included psychometric studies focused on adults, reported on measures for OD-related conditions, described non-instrumental clinical assessments, reported on validity or reliability, and were published in English. Methodological quality was assessed using the standard quality assessment QualSyst. Most measures targeted only restricted subdomains within the conceptual framework of non-instrumental clinical assessments. Across the 16 measures, hypothesis testing and reliability were the most reported psychometrics, whilst structural validity and content validity were the least reported. Overall, data on the reliability and validity of the included measures proved incomplete and frequently did not meet current psychometric standards. Future research should focus on the development of comprehensive non-instrumental clinical assessments for adults with OD using contemporary psychometric research methods.
Web-Based Nomograms for Overall Survival and Cancer-Specific Survival of Bladder Cancer Patients with Bone Metastasis: A Retrospective Cohort Study from SEER Database
Authors: Yang Sheng , Zhou Hongmin , Feng Chaobo , Xu Ningze , Fan Yunshan , Zhou Zhi , Xu Yunfei , Fan Guoxin , Liao Xiang , He Shisheng
Published: January 2023

Background: Our study aimed to explore the prognostic factors of bladder cancer with bone metastasis (BCBM) and develop prediction models to predict the overall survival (OS) and cancer-specific survival (CSS) of BCBM patients. Methods: A total of 1438 patients with BCBM were obtained from the SEER database. Patients from 2010 to 2016 were randomly divided into training and validation datasets (7:3), while patients from 2017 were divided for external testing. Nomograms were established using prognostic factors identified through Cox regression analyses and validated internally and externally. The concordance index (C-index), calibration plots, and time-dependent receiver operating characteristic (ROC) curves were used to evaluate the discrimination and calibration of nomogram models, while decision curve analyses (DCA) and Kaplan-Meier (KM) curves were used to estimate the clinical applicability. Results: Marital status, tumor metastasis (brain, liver, and lung), primary site surgery, and chemotherapy were indicated as independent prognostic factors for OS and CSS. Calibration plots and the overall C-index showed a novel agreement between the observed and predicted outcomes. Nomograms revealed significant advantages in OS and CSS predictions. AUCs for internal and external validation were listed as follows: for OS, 3-month AUCs were 0.853 and 0.849; 6-month AUCs were 0.873 and 0.832; 12-month AUCs were 0.825 and 0.805; for CSS, 3-month AUCs were 0.849 and 0.847; 6-month AUCs were 0.870 and 0.824; 12-month AUCs were 0.815 and 0.797, respectively. DCA curves demonstrated good clinical benefit, and KM curves showed distinct stratification performance. Conclusion: The nomograms as web-based tools were proved to be accurate, efficient, and clinically beneficial, which might help in patient management and clinical decision-making for BCBM patients.
Characterization and Evaluation of Rapamycin-Loaded Nano-Micelle Ophthalmic Solution
Authors: Zhang Ting , Wei Chao , Wu Xianggen , Zhang Sai , Duan Fangnan , Qi Xiaolin , Shi Weiyun , Gao Hua
Published: January 2023

Rapamycin-loaded nano-micelle ophthalmic solution (RAPA-NM) offers a promising application for preventing corneal allograft rejection; however, RAPA-NM has not yet been fully characterized. This study aimed to evaluate the physicochemical properties, biocompatibility, and underlying mechanism of RAPA-NM in inhibiting corneal allograft rejection. An optimized RAPA-NM was successfully prepared using a polyvinyl caprolactam–polyvinyl acetate–polyethylene glycol (PVCL-PVA-PEG) graft copolymer as the excipient at a PVCL-PVA-PEG/RAPA weight ratio of 18:1. This formulation exhibited high encapsulation efficiency (99.25 ± 0.55%), small micelle size (64.42 ± 1.18 nm), uniform size distribution (polydispersity index = 0.076 ± 0.016), and a zeta potential of 1.67 ± 0.93 mV. The storage stability test showed that RAPA-NM could be stored steadily for 12 weeks. RAPA-NM also displayed satisfactory cytocompatibility and high membrane permeability. Moreover, topical administration of RAPA-NM could effectively prevent corneal allograft rejection. Mechanistically, a transcriptomic analysis revealed that several immune- and inflammation-related Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were significantly enriched in the downregulated genes in the RAPA-NM-treated allografts compared with the rejected allogenic corneal grafts. Taken together, these findings highlight the potential of RAPA-NM in treating corneal allograft rejection and other ocular inflammatory diseases.
Modeling of Surface Roughness in Honing Processes by Using Fuzzy Artificial Neural Networks
Authors: Buj-Corral Irene , Sender Piotr , Luis-Pérez Carmelo J.
Published: January 2023

Honing processes are abrasive machining processes which are commonly employed to improve the surface of manufactured parts such as hydraulic or combustion engine cylinders. These processes can be employed to obtain a cross-hatched pattern on the internal surfaces of cylinders. In this present study, fuzzy artificial neural networks are employed for modeling surface roughness parameters obtained in finishing honing operations. As a general trend, main factors influencing roughness parameters are grain size and pressure. Mean spacing between profile peaks at the mean line parameter, on the contrary, depends mainly on tangential and linear velocity. Grain Size of 30 and pressure of 600 N/cm2 lead to the highest values of core roughness (Rk) and reduced valley depth (Rvk), which were 1.741 µm and 0.884 µm, respectively. On the other hand, the maximum peak-to-valley roughness parameter (Rz) so obtained was 4.44 µm, which is close to the maximum value of 4.47 µm. On the other hand, values of the grain size equal to 14 and density equal to 20, along with pressure 600 N/cm2 and both tangential and linear speed of 20 m/min and 40 m/min, respectively, lead to the minimum values of core roughness, reduced peak height (Rpk), reduced valley depth and maximum peak-to-valley height of the profile within a sampling length, which were, respectively, 0.141 µm, 0.065 µm, 0.142 µm, and 0.584 µm.
Potential Therapies Targeting the Metabolic Reprogramming of Diabetes-Associated Breast Cancer
Authors: Shum Hang Chee Erin , Wu Ke , Vadgama Jaydutt , Wu Yong
Published: January 2023

In recent years, diabetes-associated breast cancer has become a significant clinical challenge. Diabetes is not only a risk factor for breast cancer but also worsens its prognosis. Patients with diabetes usually show hyperglycemia and hyperinsulinemia, which are accompanied by different glucose, protein, and lipid metabolism disorders. Metabolic abnormalities observed in diabetes can induce the occurrence and development of breast cancer. The changes in substrate availability and hormone environment not only create a favorable metabolic environment for tumorigenesis but also induce metabolic reprogramming events required for breast cancer cell transformation. Metabolic reprogramming is the basis for the development, swift proliferation, and survival of cancer cells. Metabolism must also be reprogrammed to support the energy requirements of the biosynthetic processes in cancer cells. In addition, metabolic reprogramming is essential to enable cancer cells to overcome apoptosis signals and promote invasion and metastasis. This review aims to describe the major metabolic changes in diabetes and outline how cancer cells can use cellular metabolic changes to drive abnormal growth and proliferation. We will specifically examine the mechanism of metabolic reprogramming by which diabetes may promote the development of breast cancer, focusing on the role of glucose metabolism, amino acid metabolism, and lipid metabolism in this process and potential therapeutic targets. Although diabetes-associated breast cancer has always been a common health problem, research focused on finding treatments suitable for the specific needs of patients with concurrent conditions is still limited. Most studies are still currently in the pre-clinical stage and mainly focus on reprogramming the glucose metabolism. More research targeting the amino acid and lipid metabolism is needed.
The Role of Heat Acclimation in Thermotolerance of Chickpea Cultivars: Changes in Photochemical and Biochemical Responses
Authors: Arslan Özlem
Published: January 2023

This study was conducted to determine the effects of heat stress on the physiological and biochemical responses of chickpea (Cicer arietinum L.; Diyar and Küsmen-99) cultivars that are both heat acclimated and non-acclimated. The seedlings were grown in soil for 15 days and then exposed to heat stress (35 °C, 5 days) after heat acclimation (30 °C, 2 days) or non-acclimation (25 °C, 2 days). Chlorophyll a fluorescence (ChlF) measurements were analyzed using the JIP test. Heat acclimation had no significant effect on ChlF parameters. Seedlings exposed to higher temperatures by acclimation were more tolerant in terms of ChlF parameters and Diyar had a better photochemical activity of photosystem II (PSII). Heat stress resulted in a decrease in electron transport efficiency, quantum yield, photosynthetic performance, and driving force in both chickpea cultivars, while K-band, L-band, and quantum yield of dissipation increased, especially in the non-acclimated cultivars. Additionally, ion leakage (RLR), malondialdehyde (MDA) content, and H2O2 synthesis increased in the cultivars, while water content (RWC), chlorophyll (a + b) content, and carotenoid content of the cultivars decreased. On the other hand, the cultivars attempted to eliminate reactive oxygen species (ROS) by increasing the content of anthocyanins and flavonoids and the activity of antioxidant enzymes (SOD and POD) under heat stress. Heat acclimation alleviated the negative effects of heat stress on each cultivar’s water content, chlorophyll and carotenoid content, membrane damage, photosynthetic activity, and antioxidant defense systems. The results of this study showed that, by providing heat acclimation more effectively, Diyar was better able to cope with the biochemical and physiological alterations that could be resulted from heat stress.
Diamine Oxidase Activity Deficit and Idiopathic Rhinitis: A New Subgroup of Non-Allergic Rhinitis?
Authors: Mayo-Yáñez Miguel , Díaz-Díaz Andrea , Calvo-Henríquez Christian , Lechien Jerome R. , Vaira Luigi A. , Figueroa Angélica
Published: January 2023

Idiopathic rhinitis represents more than 50% of non-allergic rhinitis, a heterogeneous group that involves the symptomatic inflammation of the nasal mucosa. The TRPV1 receptor of unmyelinated C-type neurons appears to be involved in its pathophysiology. Histamine, whose main catabolic enzyme is DAO, is one of the mediators that can activate this receptor. The failure of DAO causes an increase in the level of histamine in the body and, consequently, the activation of TRPV1. The objective was to investigate the existence of a DAO enzyme activity deficit in idiopathic rhinitis and its correlation with symptoms. A cross-sectional study was conducted in 116 idiopathic rhinitis patients, and DAO activity, nasal peak inspiratory flow, and rhinitis severity were recorded. The prevalence of a DAO activity deficit was 41.38% (95%CI 0.33–0.50; p = 0.05). The DAO activity in patients with mild rhinitis was 52.93 ± 8.72 HDU/mL, in those with moderate rhinitis it was 120.33 ± 71.63 HDU/mL, and in those with severe rhinitis it was 92.58 ± 27.75 HDU/mL (p = 0.006). The NPIF in patients with a DAO activity deficit was 107.92 ± 34.05 L/min, compared to 72.35 ± 27.16 L/min in patients with normal enzymatic activity (p < 0.001), demonstrating a linear correlation between activity levels and nasal obstruction (−0.45; p < 0.001). Therefore, patients with a DAO deficiency and idiopathic rhinitis could present a milder disease course, because the repeated and continuous activation of TRPV1 led to a partial or total decrease in their response (desensitization). This new theory represents a different perspective for the study of idiopathic rhinitis and its relationship with TRPV1, with the regulation or modulation of the desensitization of TRPV1 being an important therapeutic target for patients with idiopathic rhinitis in the future.
Trace Element Uptake by Willows Used for the Phytoremediation of Biosolids
Authors: Contangelo Angela , Esperschuetz Juergen , Robinson Brett H.
Published: January 2023

The land application of biosolids can result in the unacceptable accumulation of Trace Elements (TEs) in agricultural soil and potentially introduce xenobiotics and pathogens into the food chain. Phytoremediation of biosolids aims to minimize this risk, while producing valuable biomass. Willows, well known to accumulate zinc (Zn), are used extensively in farming systems for soil conservation, shelter and as feed supplements with demonstrable health benefits. Potentially, biosolids phytoremediation could occur on marginal lands adjacent to farmlands where willows are grown for supplementary fodder. We aimed to determine the uptake and distribution of Zn and other TEs in willows grown on soils amended with biosolids and biosolids blended with biochar, with a view to their use as stock fodder. In the Canterbury Region, New Zealand, we grew Salix ‘tangaio’ (S. matsudana X S. alba) in a greenhouse trial and field study. The biomass production of the willows was unaffected by biosolids and increased by the biosolids+biochar mixture. The addition of 4% biosolids (w/w) to the soil resulted in a foliar Zn concentration of 600–1000 mg kg−1, some 25 times higher than the average New Zealand pasture. Zinc concentrations were highest in the bottom leaves and increased throughout the season. Biosolids addition doubled the copper (Cu) concentration to 10 mg kg−1. Adding biochar to the system reduced the plant uptake of Cu and to a lesser extent Zn, while cadmium (Cd) uptake was unaffected. For Cd, Cu, and Zn, plant uptake was a function of the Ca(NO3)2-extractable concentration, both in greenhouse experiments and the field trial. Future work should determine the changes in plant TE uptake over several growing seasons.
3-Chloro-4-(p-tolyl)isothiazole-5-carbonitrile
Authors: Kalogirou Andreas S. , Koutentis Panayiotis A.
Published: January 2023

A reaction of 3-chloroisothiazole-5-carbonitrile with 1-iodo-4-methylbenzene (2 equiv.) produced 3-chloro-4-(p-tolyl)isothiazole-5-carbonitrile in a 60% yield. The compound was fully characterized.
Traditional vs. Automated Computer Image Analysis—A Comparative Assessment of Use for Analysis of Digital SEM Images of High-Temperature Ceramic Material
Authors: Jastrzębska Ilona , Piwowarczyk Adam
Published: January 2023

Image analysis is a powerful tool that can be applied in scientific research, industry, and everyday life, but still, there is more room to use it in materials science. The interdisciplinary cooperation between materials scientists and computer scientists can unlock the potential of digital image analysis. Traditional image analysis used in materials science, manual or computer-aided, permits for the quantitative assessment of the coexisting components at the cross-sections, based on stereological law. However, currently used cutting-edge tools for computer image analysis can greatly speed up the process of microstructure analysis, e.g., via simultaneous extraction of quantitative data of all phases in an SEM image. The dedicated digital image processing software Aphelion was applied to develop an algorithm for the automated image analysis of multi-phase high-temperature ceramic material. The algorithm recognizes each phase and simultaneously calculates its quantity. In this work, we compare the traditional stereology-based methods of image analysis (linear and planimetry) to the automated method using a developed algorithm. The analysis was performed on a digital SEM microstructural image of high-temperature ceramic material from the Cu-Al-Fe-O system, containing four different phase components. The results show the good agreement of data obtained by classical stereology-based methods and the developed automated method. This presents an opportunity for the fast extraction of both qualitative and quantitative from the SEM images.
Thermoanalytical and X-ray Diffraction Studies on the Phase Transition of the Calcium-Substituted La2Mo2O9 System
Authors: Žalga Artūras , Gaidamavičienė Giedrė
Published: January 2023

An aqueous sol-gel preparation technique was applied for the synthesis of calcium-substituted lanthanum molybdate with the initial composition of La2–xCaxMo2O9–x/2. The influence of the substitution effect, which plays a crucial role in the formation of final ceramics, was investigated. The thermal behavior tendencies of phase transition at elevated temperatures from the monoclinic crystal phase to cubic as well as reversible transformation were identified and discussed in detail. It was proved that the phase transformation in the obtained mixture significantly depends only on the impurities’ amount, while the partial substitution by calcium atoms above the value of x = 0.05 does not create a homogeneous multicomponent system for La2–xCaxMo2O9–x/2 composition.
Calibration of Inverted Asphalt Pavement Rut Prediction Model, Based on Full-Scale Accelerated Pavement Testing
Authors: Han Zhenqiang , Sha Aimin , Hu Liqun , Jiang Wei
Published: January 2023

This study investigates the establishment and calibration method of the rut depth (RD) prediction model of inverted asphalt pavements (IAPs), based on full-scale accelerated pavement testing (APT), which facilitates the accurate and reliable design or maintenance of IAPs. A power function is adopted for the prediction model construction of the rut progression before the failure stage, based on the typical permanent deformation progression curve of flexible pavements. The APT loading history is divided into units, according to the difference in physical conditions, providing the basis for a cumulative RD analysis and model calibration. The nonlinear incremental recursive (IR) principle is applied in the RD analysis to consider the influence of the nonlinear material property, performance deterioration, and loading history on the RD development. Further, the rut shift function relating prediction models obtained from laboratory tests and full-scale APT is established to introduce the APT data in the calibration process. Accordingly, the mechanistic-empirical RD prediction model calibration method, based on APT and the IR principle, is proposed and applied in a case study of a IAP RD prediction model calibration. Four 3.5 m × 4 m IAP test sections S1–S4 are constructed and instrumented and 700,000- and 900,000-wheel loads are applied on test sections S1–S2 and S3–S4, respectively, using the heavy vehicle simulator. The test data from the different APT load units are utilized for the model calibration, and the resultant prediction errors range from −2.16 mm to 1.18 mm. The calibrated model can also be used for the RD prediction of IAPs with other design schemes, by updating the corresponding material-related coefficients and the finite element model, which is essential for the design and maintenance of IAPs. The proposed calibration method could be a useful reference for the establishment of flexible pavement performance prediction models.
Rotating Bending Fatigue Behaviors of C17200 Beryllium Copper Alloy at High Temperatures
Authors: Lai Fuqiang , Mao Kun , Cao Changsheng , Hu Anqiong , Tu Junxiang , Lin Youxi
Published: January 2023

The purpose of this paper is to investigate the fatigue properties of C17200 alloy under the condition of quenching aging heat treatment at high temperatures, and to provide a design reference for its application in a certain temperature range. For this purpose, the tensile and rotary bending fatigue (RBF) tests were carried out at different temperatures (25 °C, 150 °C, 350 °C, and 450 °C). The tensile strength was obtained, and relationships between the applied bending stress levels and the number of fatigue fracture cycles were fitted to the stress-life (S-N) curves, and the related equations were determined. The fractured surfaces were observed and analyzed by a scanning electron microscopy (SEM). The results show that the RBF fatigue performance of C17200 alloy specimens is decreased with the increase in test temperature. When the temperature is below 350 °C, the performance degradation amplitudes of mechanical properties and RBF fatigue resistance are at a low level. However, compared to the RBF fatigue strength of 1 × 107 cycles at 25 °C, it is decreased by 38.4% when the temperature reaches 450 °C. It is found that the fatigue failure type of C17200 alloy belongs to surface defect initiation. Below 350 °C, the surface roughness of the fatigue fracture is higher, which is similar to the brittle fracture, so the boundary of the fracture regions is not obvious. At 450 °C, due to the further increase in temperature, oxidation occurs on the fracture surface, and the boundary of typical fatigue zone is obvious.
Special Issue “Advanced Pulse Laser Machining Technology”
Authors: Krüger Jörg , Bonse Jörn
Published: January 2023

“Advanced Pulse Laser Machining Technology” is a rapidly growing field that can be tailored to special industrial and scientific applications [...]
Modeling Materials Coextrusion in Polymers Additive Manufacturing
Authors: Sponchiado Riccardo , Rosso Stefano , Dal Fabbro Pierandrea , Grigolato Luca , Elsayed Hamada , Bernardo Enrico , Maltauro Mattia , Uccheddu Francesca , Meneghello Roberto , Concheri Gianmaria , Savio Gianpaolo
Published: January 2023

Material extrusion additive manufacturing enables us to combine more materials in the same nozzle during the deposition process. This technology, called material coextrusion, generates an expanded range of material properties, which can gradually change in the design domain, ensuring blending or higher bonding/interlocking among the different materials. To exploit the opportunities offered by these technologies, it is necessary to know the behavior of the combined materials according to the materials fractions. In this work, two compatible pairs of materials, namely Polylactic Acid (PLA)-Thermoplastic Polyurethane (TPU) and Acrylonitrile Styrene Acrylate (ASA)-TPU, were investigated by changing the material fractions in the coextrusion process. An original model describing the distribution of the materials is proposed. Based on this, the mechanical properties were investigated by analytical and numerical approaches. The analytical model was developed on the simplified assumption that the coextruded materials are a set of rods, whereas the more realistic numerical model is based on homogenization theory, adopting the finite element analysis of a representative volume element. To verify the deposition model, a specific experimental test was developed, and the modeled material deposition was superimposed and qualitatively compared with the actual microscope images regarding the different deposition directions and material fractions. The analytical and numerical models show similar trends, and it can be assumed that the finite element model has a more realistic behavior due to the higher accuracy of the model description. The elastic moduli obtained by the models was verified in experimental tensile tests. The tensile tests show Young’s moduli of 3425 MPa for PLA, 1812 MPa for ASA, and 162 MPa for TPU. At the intermediate material fraction, the Young’s modulus shows an almost linear trend between PLA and TPU and between ASA and TPU. The ultimate tensile strength values are 63.9 MPa for PLA, 35.7 MPa for ASA, and 63.5 MPa for TPU, whereas at the intermediate material fraction, they assume lower values. In this initial work, the results show a good agreement between models and experiments, providing useful tools for designers and contributing to a new branch in additive manufacturing research.
Polyethylene Glycol-Isophorone Diisocyanate Polyurethane Prepolymers Tailored Using MALDI MS
Authors: Blaj Diana-Andreea , Diaconu Alexandra-Diana , Harabagiu Valeria , Peptu Cristian
Published: January 2023

The reaction of diols with isocyanates, leading to mono-functional and di-functional prepolymers may be investigated using various characterization methods which show the overall conversion of isocyanate monomers. On the other hand, matrix-assisted laser desorption ionization mass spectrometry (MALDI MS) polymer characterization can be employed to identify the monomer units, the end-group functionalities, molecular weight averages, and to determine the copolymer sequence. Herein, we focus on prepolymer synthesis using isophorone diisocyanate (IPDI), a widely used diisocyanate for prepolymers preparation, especially in waterborne polyurethane materials. Thus, the reaction between polyethylene glycol diol and IPDI was in-depth investigated by mass spectrometry to determine the influence of the reaction parameters on the prepolymer’s structure. The relative content of the different functional oligomer species at given reaction times was determined in the reaction mixture. More specifically, the offline analysis revealed the influence of reaction parameters such as reaction temperature, the concentration of reactants, and the amount of dibutyltin dilaurate catalyst. The established MALDI MS analysis involved measurements of samples, first, directly collected from the reaction mixture and secondly, following derivatization with methanol. The obtained results revealed the effects of reaction parameters on the functionalization reaction with isocyanates, allowing to achieve a better reaction control.
Influence of Fiber Type and Dosage on Tensile Property of Asphalt Mixture Using Direct Tensile Test
Authors: Yang Shuyao , Zhou Zhigang , Li Kai
Published: January 2023

In engineering practice, fiber addition is a frequently used method to improve the tensile property of asphalt mixture. However, the optimum fiber type and dosage have not been determined by direct tensile tests. In this paper, monotonic tensile tests were conducted on three kinds of stone mastic asphalt (SMA13) mixtures, that is, granular-lignin-fiber-reinforced SMA (GFSMA), flocculent-lignin-fiber-reinforced SMA (FFSMA), and basalt-fiber-reinforced SMA (BFSMA) at different fiber dosages to probe the influence of fiber dosage on their tensile mechanical indexes (tensile strength, ultimate strain, elastic modulus, and strain energy density) and to determine the optimum dosage of each kind of fiber. The results showed that with the elevation of fiber dosage, the tensile strength, elastic modulus, and strain energy density of all three kinds of asphalt mixtures increased first and then decreased, while the ultimate strain increased constantly. The optimum dosage was 0.50 wt%, 0.45 wt%, and 0.50 wt% for granular lignin fiber, flocculent lignin fiber, and basalt fiber, respectively. On this basis, strain-controlled direct tensile fatigue tests were conducted on the three kinds of asphalt mixtures at the corresponding optimum fiber dosage. The results indicated that asphalt mixture reinforced with 0.50 wt% granular lignin fiber exhibited ideal direct tensile fatigue performance with respect to fatigue life and accumulative dissipated energy. Therefore, granular lignin fiber is recommended as the favorable fiber type, and its optimum dosage is 0.50 wt%. Moreover, scanning electron microscopy (SEM) demonstrated that the essence of the impact of fiber dosage and type on the tensile property of SMA is whether the reinforcement effect on the mixture matrix outweighs the negative effect of the defects between fiber and mixture matrix, or whether the reverse applies.
Investigation on the Carbonation Behavior of Alkali-Activated Pastes Served under Windy Environments
Authors: Cui Dong , Shen Lingshu , Shen Yidong , Han Guantong , Xie Xiaoying , Cao Qianfei , Wang Jing , Wei Hao , Wang Qiannan , Zheng Keren
Published: January 2023

Most reinforced concrete structures serve under windy environments, and the carbonation resistance under that circumstance exhibits significant difference from that under the steady (no wind) environment. In this study, a windy environment was simulated using one self-developed wind tunnel, and alkali-activated slag/fly ash paste specimens were adopted for the carbonation under variant windy environments. Meanwhile, to reveal the effect of inner humidity on the carbonation, sliced alkali-activated materials (AAM) were mass-balanced first to variant humidity, and were then carbonated under a 2.5 m/s windy environment. With the assistance of computed tomography (CT), the structure of AAM at variant carbonation ages was rendered. The experimental result showed that wind is capable of promoting the exchange of moisture between the sample inside and the outer atmosphere, leading to faster carbonation as compared to that under no wind environment. When preconditioned to lower inner humidity, the carbonation rate of AAM was faster because the larger gaseous space benefited the intrusion of both CO2 and moisture. Furthermore, when preconditioned to lower humidity, the cracking extent of AAM was severer, which also contributed to the faster carbonation. Moreover, compared with ordinary Portland cement (OPC), the carbonation front on each instant 1D gray-scale value profile was broader, which suggested that the carbonation progress of AAM under windy environments was no longer controlled solely by diffusion. In addition, the gray-scale value on instant 1D profile fluctuated drastically, which verified cracking in AAM carbonated under windy environments. The current work not only deepens the understanding of the carbonation mechanism in-site (mostly under windy environments), but also helps to develop more environment-friendly construction material, with better durability performance.
X-ray Excited Optical Luminescence of Eu in Diamond Crystals Synthesized at High Pressure High Temperature
Authors: Lebedev Vasily T. , Shakhov Fedor M. , Vul Alexandr Ya. , Zakharov Arcady A. , Zinoviev Vladimir G. , Orlova Vera A. , Fomin Eduard V.
Published: January 2023

Powder diamonds with integrated europium atoms were synthesized at high pressure (7.7 GPa) and temperature (1800 °C) from a mixture of pentaerythritol with pyrolyzate of diphthalocyanine (C64H32N16Eu) being a special precursor. In diamonds prepared by X-ray fluorescence spectroscopy, we have found a concentration of Eu atoms of 51 ± 5 ppm that is by two orders of magnitude greater than that in natural and synthetic diamonds. X-ray diffraction, SEM, X-ray exited optical luminescence, and Raman and IR spectroscopy have confirmed the formation of high-quality diamond monocrystals containing Eu and a substantial amount of nitrogen (~500 ppm). Numerical simulation has allowed us to determine the energy cost of 5.8 eV needed for the incorporation of a single Eu atom with adjacent vacancy into growing diamond crystal (528 carbons).
Physical Model Experiments on Failure Mechanism on Slopes of Weathered Basalt Soils during Heavy Rainfall Events
Authors: Zhang Qingzhao , Luo Zejun , Chen Ying , Wang Zhen
Published: January 2023

Basalt platforms are widely distributed in many areas of China, where landslides occur frequently. It is well recognized that landslide hazards seriously threaten engineering constructions and property safety. It is, therefore, of great significance to understand deformation and failure behaviors and their mechanisms in basalt slopes to reduce the loss caused by landslides. In this work, the Pengshan Landslide in Zhejiang Province is taken as a prototype and slope model tests are carried out. During the tests, real-time monitoring of pore pressure, earth pressure and slope deformation is conducted. Based on the experimental data, the influence of rainfall intensity and the thickness of a weak interlayer on the slope stability are obtained. It is demonstrated that the rainfall and weak interlayer are the most important factors causing the slope instability of a basalt platform. Furthermore, damage from a basalt platform slope usually starts from local failure, and the slope foot is the most likely sliding part. Moreover, when the rainfall intensity is doubled, the initial deformation time of the slope is reduced by about half and the final failure time is advanced by one-third. In addition, when the thickness of the weak interlayer is doubled, the initial deformation time of slope is shortened by about half and the final failure time is advanced by one-quarter.
Comparison of Milled Full-Arch Implant-Supported Frameworks Realised with a Full Digital Workflow or from Conventional Impression: A Clinical Study
Authors: Pera Francesco , Pesce Paolo , Bagnasco Francesco , Pancini Nicolò , Carossa Massimo , Baldelli Lorenzo , Annunziata Marco , Migliorati Marco , Baldi Domenico , Menini Maria
Published: January 2023

Background: The aim of the present study was to investigate the accuracy of a new digital impression system, comparing it to the plaster impression technique in the realization of full-arch implant-supported metal frameworks. Methods: We took 11 scans (8 of the upper maxilla and 3 of the lower jaw) on a sample of nine patients previously rehabilitated with fixed full-arch screw-retained prostheses following the Columbus Bridge Protocol (CBP) with four to six implants (total: 51) since at least 4 months. Two impressions were taken for each dental arch: one analogic plaster impression using pick-up copings and an open tray technique and a second one using an intra-oral scanner. Two milled metal substructures were realised. The precision and passivity of the substructures were clinically analysed through the Sheffield test and endo-oral radiographs. Laboratory scans of the plaster casts obtained from an intra-oral scanner (IOS) and of the plaster casts obtained from traditional impression were compared with the intraoral scans following Hausdorff’s method and an industrial digital method of optical detection to measure discrepancies. A Mann–Whitney test was performed in order to investigate average distances between surfaces after the superposition. Results: The Sheffield test demonstrated an excellent passivity of the frameworks obtained through both the digital and the analogic method. In 81.81% of cases (n = 9) both substructures were found to have a perfect fit with excellent passivity, while in 18.18% (n = 2) of cases the substructures were found to have a very slight discrepancy. From the radiographic examination, no gaps between the frameworks and the implant heads or multiunit abutments were observed, with 100% accuracy. By superimposing digital files of scans according to Hausdorff’s method, a statistically significant discrepancy (p = 0.006) was found between the digital scans and the digital models obtained from plaster impressions. Three-dimensional optical detection found a mean discrepancy of 0.11 mm between the analogic cast and the cast derived from the digital impression. Conclusions: The present study clinically demonstrates that milled implant-supported full-arch frameworks obtained through a digital scan and the herein described technique have an accuracy comparable to those obtained with traditional plaster impression.
Correlations between Microscale Indentation Creep and Macroscale Tensile Creep of Polymers
Authors: Slouf Miroslav , Steinhart Milos , Nemecek Pavel , Gajdosova Veronika , Hodan Jiri
Published: January 2023

We compared the results of various microscale indentation creep (microcreep) measurements with macroscale tensile creep (macrocreep) measurements of three common polymers: high-density polyethylene (PE), polypropylene (PP), and polystyrene (PS). The main objective was to verify if the short-term microcreep experiments could predict long-term macrocreep behavior of the selected polymers, whose properties ranged from very soft and ductile (PE) to very hard and brittle (PS). The second objective was to compare several creep predictive schemes: the empirical power law model (PL) and several types of phenomenological elasto-visco-plastic models (EVP). In order to facilitate this task, we developed a universal program package named MCREEP, which fits PL and EVP models to both tensile and indentation creep data. All experimental results and theoretical predictions documented that: (i) regardless of the creep experiment type, both micro- and macrocreep resistance increased in the following order: PE < PP < PS, (ii) the short-term microcreep experiments could be used to predict qualitatively the long-term macrocreep behavior, and (iii) the simple empirical power law model yielded better predictions of long-term creep behavior than the more sophisticated elasto-visco-plastic models.