bluuebunny/crossref_metadata_2025 huggingface dataset:
Reduction of Cancer-Induced Thrombocytosis as a Biomarker of Improved Outcomes in Advanced Gastric Cancer
Authors: Konopka Kamil , Frączek Paulina , Lubaś Maciej , Micek Agnieszka , Kwinta Łukasz , Streb Joanna , Potocki Paweł , Wysocki Piotr
Published: February 2022

Background: Interplay between non-specific inflammatory reaction and tumor microenvironment in gastric cancer (GC) can be measured indirectly by assessing fluctuations in concentration of platelets. Cytotoxic chemotherapy affects these morphotic elements directly by inducing myelosuppression. It was hypothesized that chemotherapy not only directly affects malignant cells, but also through immunomodulation related to myelosuppression. Methods: Metastatic GC patients (N: 155) treated with chemotherapy +/− trastuzumab were enrolled in this retrospective study. Platelet pretreatment concentration (PLT-count) and the deepest level of platelet reduction, as well as other inflammatory and general confounders were collected in the first 12 weeks of treatment (PLT-red). Martingale residuals were used to visualize the relationship between PLT-count, PLT-red, and overall survival (OS). Multiple multivariate Cox regression models were built to assess the impact of platelet reduction on OS and progression-free survival (PFS). Results: Reduction of PLT (PLT-red) to 60% of baseline concentration was associated with improved survival rates (HR = 0.60, p = 0.026 for OS and HR 0.56, p = 0.015 for PFS). Cross-classification into four groups based on PLT-count (high vs low) and PLT-red (high vs low) showed significantly worse survival rates in both high PLT-count (HR = 3.60, p = 0.007 for OS and HR = 2.97, p = 0.024 for PFS) and low PLT-count (HR = 1.75, p = 0.035 for OS and HR = 1.80, p = 0.028 for PFS) patients with insufficient platelets reduction. Conclusion: Thrombocytosis reduction represents a novel, clinically important, prognostic factor for OS and PFS in patients with stage IV GC.
Is Hysteroscopy Prior to IVF Associated with an Increased Probability of Live Births in Patients with Normal Transvaginal Scan Findings after Their First Failed IVF Trial?
Authors: Zikopoulos Athanasios , Galani Apostolia , Siristatidis Charalampos , Georgiou Ioannis , Mastora Eirini , Paraskevaidi Maria , Zikopoulos Konstantinos , Kolibianakis Efstratios
Published: February 2022

(1) Background: Nowadays, pregnancy can be achieved by in vitro fertilisation (IVF) or by intracytoplasmic sperm injection (ICSI) for many infertile couples. However, implantation failure still remains a significant problem and it can be stressful for both patients and doctors. One of the key players for pregnancy achievement is the uterine environment. Hysteroscopy is the most reliable method to evaluate the uterine cavity and to identify any intauterine pathology. The aim of this retrospective study was to compare live birth ranges in between women who after a first failed IVF/ICSI attempt underwent a hysteroscopy and those who were evaluated by a transvaginal scan. (2) The retrospective study took place at the Assisted Reproductive Unit of the University Hospital of Ioannina, Greece, from 2017 to 2020. It included 334 women with normal findings in a repeat ultrasound scan after a failed IVF/ICSI trial, 137 of whom underwent in turn diagnostic hysteroscopy before the next IVF/ICSI. (3) Results: Live birth rates were higher in the study group (58/137 vs. 52/197 p = 0.0025). Abnormal endometrial findings were identified in 30% of the patients of the study group. (4) Conclusions: The addition of hysteroscopy as an additional investigation to those patients with a first failed IVF/ICSI could improve the rates of live births. A properly conducted RCT could lead to a robust answer.
Acute-Phase Inflammatory Reaction Predicts CMR Myocardial Scar Pattern and 2-Year Mortality in STEMI Patients Undergoing Primary PCI
Authors: Mester Andras , Rat Nora , Benedek Theodora , Opincariu Diana , Hodas Roxana , Chitu Monica , Benedek Imre
Published: February 2022

(1) Background: The inflammatory response following MI plays an important role in the healing, scar formation, and left ventricle (LV) remodeling. Cardiac magnetic resonance (CMR) imaging can accurately quantify the extent of myocardial scarring. The study aimed to investigate: (a) the relationship between acute inflammatory response and the CMR parameters of the scarring extent, and (b) the predictive power of inflammatory biomarkers and myocardial scarring for 2-year mortality. (2) Methods: The study included 202 STEMI patients, who underwent pPCI. Serum hs-CRP, IL-6, P-selectin, E-selectin, I-CAM, and V-CAM levels were determined at admission, and hs-CRP on the fifth day. Patients underwent LGE-CMR after 1 month, for LV volumes, ejection fraction (EF), infarct size (IS), and transmurality. Subjects were divided into tertiles according to the IS, and 2-year all-cause mortality was determined. (3) Results: IL-6 was associated with IS (r = 0.324, p = 0.01), increased transmurality index (r = 0.3, p = 0.01), and lower LVEF (r = −0.3, p = 0.02). Admission hs-CRP levels were not associated with IS, transmurality, or mortality, while hs-CRP at day 5 was a significant predictor for IS (AUC = 0.635, p = 0.05) as well as IL-6 levels (AUC = 0.685, p < 0.001). Mortality was significantly higher in the upper IS tertiles (6% vs. 8.7% vs. 24.52%, p = 0.005). IS was a significant predictor of 2-year mortality (AUC = 0.673, p = 0.002), with a cut-off value of 28.81 g, as well as high transmurality (AUC = 0.641, p = 0.013), with a cut off value of 18.38 g. (4) Conclusions: The serum levels of IL-6 and day-5 hs-CRP predict IS and transmurality, and day-5 hs-CRP levels are independent predictors of 2-year mortality in STEMI patients treated with pPCI. The CMR pattern of myocardial scarring after 1 month, as expressed by the magnitude of IS and transmurality, is a significant predictor for 2-year mortality after revascularized STEMI.
EHO-85: A Multifunctional Amorphous Hydrogel for Wound Healing Containing Olea europaea Leaf Extract: Effects on Wound Microenvironment and Preclinical Evaluation
Authors: Casado-Díaz Antonio , La Torre Manuel , Priego-Capote Feliciano , Verdú-Soriano José , Lázaro-Martínez José Luis , Rodríguez-Mañas Leocadio , Berenguer Pérez Miriam , Tunez Isaac
Published: February 2022

The prevalence of chronic wounds is increasing due to the population aging and associated pathologies, such as diabetes. These ulcers have an important socio-economic impact. Thus, it is necessary to design new products for their treatment with an adequate cost/effectiveness ratio. Among these products are amorphous hydrogels. Their composition can be manipulated to provide a favorable environment for ulcer healing. The aim of this study was to evaluate a novel multifunctional amorphous hydrogel (EHO-85), containing Olea europaea leaf extract, designed to enhance the wound healing process. For this purpose, its moistening ability, antioxidant capacity, effect on pH in the wound bed of experimental rats, and the effect on wound healing in a murine model of impaired wound healing were assessed. EHO-85 proved to be a remarkable moisturizer and its application in a rat skin wound model showed a significant antioxidant effect, decreasing lipid peroxidation in the wound bed. EHO-85 also decreased the pH of the ulcer bed from day 1. In addition, in mice (BKS. Cg-m +/+ Leprdb) EHO-85 treatment showed superior wound healing rates compared to hydrocolloid dressing. In conclusion, EHO-85 can speed up the closure of hard-to-heal wounds due to its multifunctional properties that are able to modulate the wound microenvironment, mainly through its remarkable effect on reactive oxygen species, pH, and moistening regulation.
Relief Effect of Carbon Dioxide Insufflation in Transnasal Endoscopy for Health Checks—A Prospective, Double-Blind, Case-Control Trial
Authors: Fujisawa Toshio , Fukuda Hiroshi , Sakamoto Naoto , Hojo Mariko , Tomishima Ko , Ishii Shigeto , Yokokawa Hirohide , Saita Mizue , Naito Toshio , Nagahara Akihito , Watanabe Sumio , Isayama Hiroyuki
Published: February 2022

CO2 insufflation has proven effective in reducing patients’ pain after colonoscopies but has not been examined in esophagogastroduodenoscopies. Therefore, we examined the effect of CO2 insufflation in examinees who underwent transnasal endoscopies without sedation. This study is a single-center, prospective, double-blind, case-control trial conducted between March 2017 and August 2018. Subjects were assigned weekly to receive insufflation with either CO2 or air. The primary outcome was improvement of abdominal pain and distension at 2 h and 1-day postprocedure. In total, 336 and 338 examinees were assigned to the CO2 and air groups, respectively. Visual analog scale (VAS) scores for abdominal distension (15.4 vs. 25.5; p < 0.001) and distress from flatus (16.0 vs. 28.8; p < 0.001) at 2 h postprocedure were significantly reduced in the CO2 group. VAS scores for pain during the procedure (33.5 vs. 37.1; p = 0.059) and abdominal pain after the procedure (3.9 vs. 5.7; p = 0.052) also tended to be lower at 2 h postprocedure, but all parameters showed no significant difference at 1-day postprocedure. All procedures were safely completed through the planned program, and no apparent adverse events requiring treatment or follow-up occurred. In conclusion, CO2 insufflation may reduce postprocedural abdominal discomfort from transnasal esophagogastroduodenoscopies. (UMIN000028543).
Predictors of Referral to Cardiac Rehabilitation in Patients following Hospitalisation with Heart Failure: A Multivariate Regression Analysis
Authors: Giuliano Catherine , Vicendese Don , Vogrin Sara , Lane Rebecca , Driscoll Andrea , Dinh Diem , Palmer Katie , Levinger Itamar , Neil Christopher
Published: February 2022

Background: This exploratory observational case–control study investigated the rate of referral to cardiac rehabilitation (CR) among patients hospitalised with heart failure (HF) and identified factors associated with referral. Methods: Patients hospitalised with HF as identified by the Victorian Cardiac Outcomes Registry HF study were included. Factors found to be univariately associated with referral were selected for multivariate logistic regression. Results: Among 1281 patients (mean age: 76.9 years; 32.8% HFrEF and 33.9% HfpEF), 125 (9.8%) were referred to CR. Patients referred were younger (73.6 (2.7, 81.5) vs. 80.2 (71.1, 86.5) p < 0.001) and were more likely to be men (72%, p < 0.001). Factors associated with referral included inpatient percutaneous coronary intervention (OR, 3.31; 95% CI, 1.04–10.48; p = 0.04), an aetiology of ischaemic or rhythm-related cardiomyopathy, and anticoagulants prescribed on discharge. Factors that lowered the likelihood of referral included older age, female, receiving inpatient oxygen therapy, and the presence of chronic obstructive pulmonary disease (COPD) or anaemia. Conclusions: The rate of referral to CR following hospitalisation with HF is low. Shortfalls are particularly evident among females, older patients, and in those with COPD or anaemia. Future studies should focus on improving referral processes and translating proven strategies that increase referrals to CR into practice.
Adalimumab and ABP 501 in the Treatment of a Large Cohort of Patients with Inflammatory Arthritis: A Real Life Retrospective Analysis
Authors: Becciolini Andrea , Parisi Simone , Caccavale Rosalba , Bravi Elena , Lumetti Federica , Andracco Romina , Volpe Alessandro , Gardelli Lucia , Girelli Francesco , Di Donato Eleonora , Santilli Daniele , Lucchini Gianluca , Ditto Maria Chiara , Platè Ilaria , Arrigoni Eugenio , Mozzani Flavio , Riva Michele , Marchetta Antonio , Fusaro Enrico , Sandri Gilda , Salvarani Carlo , Paroli Marino , Ariani Alarico
Published: February 2022

The recent introduction of ABP 501, an adalimumab biosimilar, in the treatment of rheumatic diseases was supported by a comprehensive comparability exercise with its originator. On the other hand, observational studies comparing adalimumab and ABP 501 in inflammatory arthritis are still lacking. The main aim of this study is to compare the clinical outcomes of the treatment with adalimumab, both the originator and ABP 501, in a large cohort of patients affected by autoimmune arthritis in a real life setting. We retrospectively analysed the baseline characteristics and the retention rate in a cohort of patients who received at least a course of adalimumab (originator or ABP 501) from January 2003 to December 2020. We stratified the study population according to adalimumab use: naive to original (oADA), naive to ABP 501 (bADA) and switched from original to ABP 501 (sADA). The oADA, bADA and sADA groups included, respectively, 724, 129 and 193 patients. In each group, the majority of patients had a diagnosis of rheumatoid arthritis. The total observation period was 9805.6 patient-months. The 18-month retentions rate in oADA, bADA and sADA was, respectively, 81.5%, 84.0% and 88.0% (p > 0.05). The factors influencing the adalimumab retention rate were an axial spondylarthritis diagnosis (Hazard Ratio (HR) 0.70; p = 0.04), switch from oADA to ABP 501 (HR 0.53; p = 0.02) and year of prescription (HR 1.04; p = 0.04). In this retrospective study, patients naive to the adalimumab originator and its biosimilar ABP 501 showed the same retention rate. Patients switching from the originator to biosimilar had a higher retention rate, even though not statistically significant, when compared to naive.
Ultrasonographic Confirmation of Nasogastric Tube Placement in the COVID-19 Era
Authors: Tsolaki Vasiliki , Zakynthinos George E. , Zygoulis Paris , Bardaka Fotini , Malita Aikaterini , Aslanidis Vasileios , Zakynthinos Epaminondas , Makris Demosthenes
Published: February 2022

Background: Nasogastric tube (NGT) placement is a daily routine in the Intensive Care Unit (ICU), and misplacement of the NGT can cause serious complications. In COVID-19 ARDS patients, proning has emerged the need for frequent NGT re-evaluations. The gold standard technique, chest X-ray, is not always feasible. In the present study we report our experience with the use of ultrasonographic confirmation of NGT position. Methods: A prospective study in 276 COVID-19 ARDS patients admitted after intubation in the ICU. Ultrasonographic evaluation was performed using longitudinal or sagittal epigastric views. Examinations were performed during the initial NGT placement and every time the patients returned to the supine position after they had been proned or whenever critical care physicians or nurses considered that reconfirmation was necessary. Results: Ultrasonographic confirmation of correct NGT placement was feasible in 246/276 (89.13%) patients upon ICU admission. In 189/246 (76.8%) the tube could be visualized in the stomach (two parallel lines), in 172/246 (69.9%) the ultrasonographic whoosh test (“flash” due to air instillation through the tube, seen with ultrasonography) was evident, while in 164/246 (66.7%) both tests confirmed correct NGT placement. During ICU stay 590 ultrasonographic NGT evaluations were performed, and in 462 (78.14%) cases correct NGT placement were confirmed. In 392 cases, a chest X-ray was also ordered. The sensitivity of ultrasonographic NGT confirmation in these cases was 98.9%, specificity 57.9%, PPV 96.2%, and NPV 3.8%. The time for the full evaluation was 3.8 ± 3.4 min. Conclusion: Ultrasonographic confirmation of correct NGT placement is feasible in the initial placement, but also whenever needed thereafter, especially in the COVID-19 era, when changes in posture have become a daily practice in ARDS patients.
Metastatic Pattern of Truncal and Extremity Leiomyosarcoma: Retrospective Analysis of Predictors, Outcomes, and Detection
Authors: Tigchelaar Seth S. , Frey Christopher , Sivaraj Dharshan , Segovia Nicole A. , Mohler David G. , Steffner Robert J. , Avedian Raffi S.
Published: February 2022

Leiomyosarcomas (LMS) are a heterogenous group of malignant mesenchymal neoplasms with smooth muscle origin and are classified as either non-uterine (NULMS) or uterine (ULMS). Metastatic pattern, prognostic factors, and ideal staging/surveillance studies for truncal and extremity LMS have not been defined. A retrospective analysis of patients diagnosed with histopathology-confirmed truncal or extremity LMS between 2009 and 2019 was conducted. Data collected included demographics, tumor characteristics, staging, surveillance, and survival endpoints. The primary site was defined as: (1) extremity, (2) flank/Pelvis, or (3) chest wall/Spine. We identified 73 patients, 23.3% of which had metastatic LMS at primary diagnosis, while 68.5% developed metastatic disease at any point. The mean metastatic-free survival from primary diagnosis of localized LMS was 3.0 ± 2.8 years. Analysis of prognostic factors revealed that greater age (≥50 years) at initial diagnosis (OR = 3.74, p = 0.0003), higher tumor differentiation scores (OR = 12.09, p = 0.002), and higher tumor necrosis scores (OR = 3.65, p = 0.026) were significantly associated with metastases. Older patients (≥50 years, OR = 4.76, p = 0.017), patients with larger tumors (≥5 cm or ≥10 cm, OR = 2.12, p = 0.02, OR = 1.92, p = 0.029, respectively), higher differentiation scores (OR = 15.92, p = 0.013), and higher necrosis scores (OR = 4.68, p = 0.044) show worse survival outcomes. Analysis of imaging modality during initial staging and during surveillance showed greater tumor detection frequency when PET imaging was employed, compared to CT imaging (p < 0.0001). In conclusion, truncal and peripheral extremity LMS is an aggressive tumor with high metastatic potential and mortality. While there is a significant risk of metastases to lungs, extra-pulmonary tumors are relatively frequent, and broad surveillance may be warranted.
Effect of C60 Fullerene on Recovery of Muscle Soleus in Rats after Atrophy Induced by Achillotenotomy
Authors: Nozdrenko Dmytro , Prylutska Svitlana , Bogutska Kateryna , Nurishchenko Natalia Y. , Abramchuk Olga , Motuziuk Olexandr , Prylutskyy Yuriy , Scharff Peter , Ritter Uwe
Published: February 2022

Biomechanical and biochemical changes in the muscle soleus of rats during imitation of hind limbs unuse were studied in the model of the Achilles tendon rupture (Achillotenotomy). Oral administration of water-soluble C60 fullerene at a dose of 1 mg/kg was used as a therapeutic agent throughout the experiment. Changes in the force of contraction and the integrated power of the muscle, the time to reach the maximum force response, the mechanics of fatigue processes development, in particular, the transition from dentate to smooth tetanus, as well as the levels of pro- and antioxidant balance in the blood of rats on days 15, 30 and 45 after injury were described. The obtained results indicate a promising prospect for C60 fullerene use as a powerful antioxidant for reducing and correcting pathological conditions of the muscular system arising from skeletal muscle atrophy.
A Fast-Growing Oleaginous Strain of Coelastrella Capable of Astaxanthin and Canthaxanthin Accumulation in Phototrophy and Heterotrophy
Authors: Corato Amélie , Le Thanh Tung , Baurain Denis , Jacques Philippe , Remacle Claire , Franck Fabrice
Published: February 2022

Considering the importance of microalgae as a promising feedstock for the production of both low- and high-value products, such as lipids and pigments, it is desirable to isolate strains which simultaneously accumulate these two types of products and grow in various conditions in order to widen their biotechnological applicability. A novel freshwater strain from the genus Coelastrella was isolated in Belgium. Compared to other Coelastrella species, the isolate presented rapid growth in phototrophy, dividing 3.5 times per day at a light intensity of 400 µmol·m−2·s−1 and 5% CO2. In addition, nitrogen depletion was associated with the accumulation of astaxanthin, canthaxanthin, and fatty acids, which reached ~30% of dry weight, and a majority of SFAs and MUFAs, which are good precursors for biodiesel. This strain also accumulated astaxanthin and canthaxanthin in heterotrophy. Although the content was very low in this latter condition, it is an interesting feature considering the biotechnological potential of the microalgal heterotrophic growth. Thus, due to its rapid growth in the light, its carotenogenesis, and its fatty acids characteristics, the newly identified Coelastrella strain could be considered as a potential candidate for biorefinery purposes of both low- and high-values products.
Thermal, Mechanical, and Acoustic Properties of Polydimethylsiloxane Filled with Hollow Glass Microspheres
Authors: Vlassov Sergei , Oras Sven , Timusk Martin , Zadin Veronika , Tiirats Tauno , Sosnin Ilya M. , Lõhmus Rünno , Linarts Artis , Kyritsakis Andreas , Dorogin Leonid M.
Published: February 2022

Polydimethylsiloxane (PDMS) is the most widely used silicon-based polymer due to its versatility and its various attractive properties. The fabrication of PDMS involves liquid phase cross-linking to obtain hydrophobic and mechanically flexible material in the final solid form. This allows to add various fillers to affect the properties of the resulting material. PDMS has a relatively low Thermal Conductivity (TC), in the order of 0.2 W/mK, which makes it attractive for thermal insulation applications such as sealing in construction. Although a further decrease in the TC of PDMS can be highly beneficial for such applications, most research on the thermal properties of PDMS composites have focused on fillers that increase the TC rather than decrease it. In the present work, we propose a simple and reliable method for making a PDMS-based composite material with significantly improved thermal insulation properties, by adding hollow glass microspheres (HGMs) to the mixture of the liquid base and the cross-linker (10:1 ratio), followed by degassing and heat-assisted crosslinking. We obtained a 31% reduction of thermal conductivity and a 60% increase in the elastic modulus of samples with HGM content of 17% by weight. At the same time, the sound insulation capacity of the PDMS-HGM composite is slightly decreased in comparison to pure PDMS, as a result of its lower density. Finally, the wettability of the samples had no dependence on HGM content.
Flexural and Impact Behaviors of Mortar Composite Including Carbon Fibers
Authors: Safiuddin Md. , Abdel-Sayed George , Hearn Nataliya
Published: February 2022

This study investigated the flexural and impact performances of mortar composite made with carbon fibers (MCCF). Four mortar composites (MCCF1, MCCF2, MCCF3, and MCCF4) were produced, using 1%, 2%, 3%, and 4% carbon fibers by volume, respectively. Another mortar composite without any carbon fibers (MCCF0) was prepared for its use as a control mix. The freshly mixed mortar composites were tested for inverted slump cone flow time to ensure they had an adequate workability to cast test specimens under vibration. In addition, all fresh mortar composites were examined for density and air content. The hardened mortar composites were tested for their first-crack flexural strength, ultimate flexural strength, first-crack impact resistance, and ultimate impact resistance. Moreover, the first-crack flexural toughness, ultimate flexural toughness, first-crack impact toughness, and ultimate impact toughness were determined for all hardened mortar composites. The correlations among the hardened properties of the mortar composites were also sought. Finally, the optimum fiber content was defined from the overall test results and considering the costs of the mortar composites. The test results showed that the workability and density of the fresh mortar composite decreased, whereas its air content increased due to the inclusion of carbon fibers. However, MCCF3 possessed the highest density and lowest air content among all MCCF mixes. It also had a higher workability than MCCF4. In the hardened state, the first-crack flexural strength and impact resistance, as well as the ultimate flexural strength and impact resistance of mortar composite, increased significantly with the increasing volume content of carbon fibers. In addition, the first-crack flexural toughness, ultimate flexural toughness, first-crack impact toughness, and ultimate impact toughness increased greatly with the higher volume content of carbon fibers. Strong correlations between the flexural strength and impact resistance, and between the flexural toughness and impact toughness of the mortar composites, were observed. Above all, excellent flexural strength, flexural toughness, impact resistance, and impact toughness values were observed for MCCF4 (4% carbon fibers). The 28-day ultimate flexural strength and impact resistance of MCCF4 increased by 4.6 MPa and 134 blows, respectively, as compared to MCCF0. Moreover, the 28-day ultimate flexural toughness and ultimate impact toughness values of MCCF4 were higher than that of MCCF0, by 3739.7 N-mm and 2703.3 J, respectively. However, MCCF3 (3% carbon fibers) also exhibited a good performance under flexural and impact loadings. Based on the costs of all mortar composites and their performances in both fresh and hardened states, MCCF3 was derived as the best mortar mix. This implies that 3% carbon fibers can be defined as the optimum fiber content in the context of the present study.
Coupling Analysis on Microstructure and Residual Stress in Selective Laser Melting (SLM) with Varying Key Process Parameters
Authors: Bian Peiying , Wang Chunchang , Xu Kewei , Ye Fangxia , Zhang Yongjian , Li Lei
Published: February 2022

With the application of Selective Laser Melting (SLM) technology becoming more and more widespread, it is important to note the process parameters that have a very important effect on the forming quality. Key process parameters such as laser power (P), scan speed (s), and scanning strategy (μ) were investigated by determining the correlation between the microstructure and residual stress in this paper. A total of 10 group 316L specimens were fabricated using SLM for comprehensive analysis. The results show that the key process parameters directly affect the morphology and size of the molten pool in the SLM deposition, and the big molten pool width has a direct effect on the larger grain size and crystal orientation distribution. In addition, the larger grain size and misorientation angle also affect the size of the residual stress. Therefore, better additive manufacturing grain crystallization can be obtained by reasonably adjusting the process parameter combinations. The transfer energy density can synthesize the influence of four key process parameters (P, v, the hatching distance (δ), and the layer thickness (h)). In this study, it is proposed that the accepted energy density will reflect the influence of five key process parameters, including the scanning trajectory (μ), which can reflect the comprehensive effect of process parameters more accurately.
Physical and Numerical Simulations for Predicting Distribution of Microstructural Features during Thermomechanical Processing of Steels
Authors: Poloczek Łukasz , Kuziak Roman , Pidvysots’kyy Valeriy , Szeliga Danuta , Kusiak Jan , Pietrzyk Maciej
Published: February 2022

The design of modern construction materials with heterogeneous microstructures requires a numerical model that can predict the distribution of microstructural features instead of average values. The accuracy and reliability of such models depend on the proper identification of the coefficients for a particular material. This work was motivated by the need for advanced experimental data to identify stochastic material models. Extensive experiments were performed to supply data to identify a model of austenite microstructure evolution in steels during hot deformation and during the interpass times between deformations. Two sets of tests were performed. The first set involved hot compressions with a nominal strain of 1. The second set involved hot compressions with lower nominal strains, followed by holding at the deformation temperature for different times. Histograms of austenite grain size after each test were measured and used in the identification procedure. The stochastic model, which was developed elsewhere, was identified. Inverse analysis with the objective function based on the distance between the measured and calculated histograms was applied. Validation of the model was performed for the experiments, which were not used in the identification. The distance between the measured and calculated histograms was determined for each test using the Bhattacharyya metric and very low values were obtained. As a case study, the model with the optimal coefficients was applied to the simulation of the selected industrial hot-forming process.
Recent Advances in Electronic Skins with Multiple-Stimuli-Responsive and Self-Healing Abilities
Authors: Guo Quanquan , Qiu Xiaoyan , Zhang Xinxing
Published: February 2022

Wearable electronic skin (e-skin) has provided a revolutionized way to intelligently sense environmental stimuli, which shows prospective applications in health monitoring, artificial intelligence and prosthetics fields. Drawn inspiration from biological skins, developing e-skin with multiple stimuli perception and self-healing abilities not only enrich their bionic multifunctionality, but also greatly improve their sensory performance and functional stability. In this review, we highlight recent important developments in the material structure design strategy to imitate the fascinating functionalities of biological skins, including molecular synthesis, physical structure design, and special biomimicry engineering. Moreover, their specific structure-property relationships, multifunctional application, and existing challenges are also critically analyzed with representative examples. Furthermore, a summary and perspective on future directions and challenges of biomimetic electronic skins regarding function construction will be briefly discussed. We believe that this review will provide valuable guidance for readers to fabricate superior e-skin materials or devices with skin-like multifunctionalities and disparate characteristics.
Flexible and Stretchable Bioelectronics
Authors: Chitrakar Chandani , Hedrick Eric , Adegoke Lauren , Ecker Melanie
Published: February 2022

Medical science technology has improved tremendously over the decades with the invention of robotic surgery, gene editing, immune therapy, etc. However, scientists are now recognizing the significance of ‘biological circuits’ i.e., bodily innate electrical systems for the healthy functioning of the body or for any disease conditions. Therefore, the current trend in the medical field is to understand the role of these biological circuits and exploit their advantages for therapeutic purposes. Bioelectronics, devised with these aims, work by resetting, stimulating, or blocking the electrical pathways. Bioelectronics are also used to monitor the biological cues to assess the homeostasis of the body. In a way, they bridge the gap between drug-based interventions and medical devices. With this in mind, scientists are now working towards developing flexible and stretchable miniaturized bioelectronics that can easily conform to the tissue topology, are non-toxic, elicit no immune reaction, and address the issues that drugs are unable to solve. Since the bioelectronic devices that come in contact with the body or body organs need to establish an unobstructed interface with the respective site, it is crucial that those bioelectronics are not only flexible but also stretchable for constant monitoring of the biological signals. Understanding the challenges of fabricating soft stretchable devices, we review several flexible and stretchable materials used as substrate, stretchable electrical conduits and encapsulation, design modifications for stretchability, fabrication techniques, methods of signal transmission and monitoring, and the power sources for these stretchable bioelectronics. Ultimately, these bioelectronic devices can be used for wide range of applications from skin bioelectronics and biosensing devices, to neural implants for diagnostic or therapeutic purposes.
MXene (Ti3C2Tx)-Embedded Nanocomposite Hydrogels for Biomedical Applications: A Review
Authors: Damiri Fouad , Rahman Md. Habibur , Zehravi Mehrukh , Awaji Aeshah A. , Nasrullah Mohammed Z. , Gad Heba A. , Bani-Fwaz Mutasem Z. , Varma Rajender S. , Germoush Mousa O. , Al-malky Hamdan S. , Sayed Amany A. , Rojekar Satish , Abdel-Daim Mohamed M. , Berrada Mohammed
Published: February 2022

Polymeric nanocomposites have been outstanding functional materials and have garnered immense attention as sustainable materials to address multi-disciplinary problems. MXenes have emerged as a newer class of 2D materials that produce metallic conductivity upon interaction with hydrophilic species, and their delamination affords monolayer nanoplatelets of a thickness of about one nm and a side size in the micrometer range. Delaminated MXene has a high aspect ratio, making it an alluring nanofiller for multifunctional polymer nanocomposites. Herein, we have classified and discussed the structure, properties and application of major polysaccharide-based electroactive hydrogels (hyaluronic acid (HA), alginate sodium (SA), chitosan (CS) and cellulose) in biomedical applications, starting with the brief historical account of MXene’s development followed by successive discussions on the synthesis methods, structures and properties of nanocomposites encompassing polysaccharides and MXenes, including their biomedical applications, cytotoxicity and biocompatibility aspects. Finally, the MXenes and their utility in the biomedical arena is deliberated with an eye on potential opportunities and challenges anticipated for them in the future, thus promoting their multifaceted applications.
Effect of Curing Regime on the Mechanical Strength, Hydration, and Microstructure of Ecological Ultrahigh-Performance Concrete (EUHPC)
Authors: Zuo Zhiwu , Zhang Jiachen , Li Beixing , Shen Chuqi , Xin Gongfeng , Chen Xiao
Published: February 2022

This paper investigates the effect of curing regimes (standard and steam curing) on the mechanical strength, hydration, and microstructure of ecological ultrahigh-performance concrete (EUHPC). The flowability, compressive strength, flexural strength, hydration, porosity, pore size distribution, and microstructure of UHPC with different contents of supplementary materials (silica fume, fly ash, and ground granulated blast furnace slag) were assessed. The test results showed that the compressive strength of EUHPC under steam curing was increased considerably compared to that under standard curing, while the flexural strength was mildly decreased. The steam curing could decrease the porosity of EUHPC, which ranged between 7% and 9% for standard curing, and between 3.5% and 5% for steam curing. The aperture of EUHPC was below 20 nm, mainly located in the range of 10 nm to 20 nm under standard curing, while it was less than 10 nm for steam curing. C–S–H gel was produced under steam curing, while unhydrated fly ash, mineral powder, and Ca(OH)2 crystal were observed in the amorphous C–S–H gel. The microstructure of EUHPC under steam curing was denser than that under standard curing, and the interfacial transition zones under both curing regimes were compact.
Alloy Partitioning Effect on Strength and Toughness of κ-Carbide Strengthened Steels
Authors: Field Daniel M. , Limmer Krista R. , Hornbuckle Billy C. , Pierce Dean T. , Moore Ken E. , Sebeck Katherine M.
Published: February 2022

Alloy partitioning during heat treatment in a lightweight precipitation hardened steel was investigated using transmission electron microscopy and atom probe tomography. The mechanical properties are discussed as a function of the effect of solution treatment temperature and aging time, giving rise to variations in chemical modulation. A wrought lightweight steel alloy with a nominal composition of Fe-30Mn-9Al-1Si-1C-0.5Mo (wt. %) was solution-treated between 1173–1273 K and aged at 773 K. Lower solution treatment temperatures retained a finer grain size and accelerated age hardening response that also produced an improved work hardening behavior with a tensile strength of −1460 MPa at 0.4 true strain. Atom probe tomography indicated these conditions also had reduced modulation in the Si and Al content due to the reduced aging time preventing silicon from diffusing out of the κ-carbide into the austenite. This work provides the framework for heat-treating lightweight, age hardenable steels with high strength and improved energy absorption.
Surface Functionalization of Ureteral Stents-Based Polyurethane: Engineering Antibacterial Coatings
Authors: Ecevit Kardelen , Silva Eduardo , Rodrigues Luísa C. , Aroso Ivo , Barros Alexandre A. , Silva Joana M. , Reis Rui L.
Published: February 2022

Bacterial colonization of polyurethane (PU) ureteral stents usually leads to severe and challenging clinical complications. As such, there is an increasing demand for an effective response to this unmet medical challenge. In this study, we offer a strategy based on the functionalization of PU stents with chitosan-fatty acid (CS-FA) derivatives to prevent bacterial colonization. Three different fatty acids (FAs), namely stearic acid (SA), oleic acid (OA), and linoleic acid (LinA), were successfully grafted onto chitosan (CS) polymeric chains. Afterwards, CS-FA derivatives-based solutions were coated on the surface of PU stents. The biological performance of the modified PU stents was evaluated against the L929 cell line, confirming negligible cytotoxicity of the developed coating formulations. The antibacterial potential of coated PU stents was also evaluated against several microorganisms. The obtained data indicate that the base material already presents an adequate performance against Staphylococcus aureus, which slightly improved with the coating. However, the performance of the PU stents against Gram-negative bacteria was markedly increased with the surface functionalization approach herein used. As a result, this study reveals the potential use of CS-FA derivatives for surface functionalization of ureteral PU stents and allows for conjecture on its successful application in other biomedical devices.
Surface Discharges Performance of ETFE- and PTFE-Insulated Wires for Aircraft Applications
Authors: Riba Jordi-Roger , Moreno-Eguilaz Manuel , Ibrayemov Tamerlan , Boizieau Maxence
Published: February 2022

Compared to their predecessors, the next generations of aircrafts will be more electrified, require more electrical power and operate at higher voltage levels to meet strict weight and volume constraints. The combined effect of low-pressure environments, increased voltage levels and compact designs intensifies the risks of premature insulation degradation due to electrical discharge activity. This paper studies the resistance to surface discharges of PTFE (polytetrafluoroethylene) and ETFE (ethylene tetrafluoroethylene), two insulation materials widely used in today’s aircraft wiring systems due to their outstanding properties, such as a wide temperature operation range and a high dielectric strength. The study is carried out in a low-pressure chamber, which was pressurized within the pressure range of 10–100 kPa that includes most aircraft applications. There is a compelling need for experimental data to assess the resistance of insulation materials to surface discharges at a very early stage as a function of the environmental pressure. Data on resistance to surface discharges in low-pressure environments for aeronautical applications are lacking, while most standards for insulation systems are based on tests under standard pressure conditions. The results provided in this work can be useful to design wiring systems for future more electric aircrafts, as well as to design fault detection systems for an early detection and identification of faults related to surface discharges. Therefore, the data and analysis included in this paper could be of great interest to design and develop insulation systems for wiring systems and standard assessment methods, as well as to design fault detection strategies for the early detection and identification of surface discharges for future generations of more electric aircrafts.
PBF-EB of Fe-Cr-V Alloy for Wear Applications
Authors: Franke-Jurisch Marie , Mirz Markus , Wenz Thomas , Kirchner Alexander , Klöden Burghardt , Weißgärber Thomas
Published: February 2022

Due to the small variety of materials, the areas of application of additive manufacturing in the toolmaking industry are currently still limited. In order to overcome these material restrictions, AM material development for high carbon-containing iron-based materials, which are characterized by high strength, hardness, and wear resistance, must be intensified. However, these materials are often susceptible to crack formation or lack of fusion defects during processing. Therefore, these materials are preferentially suited for electron beam powder bed fusion (PBF-EB). In this paper, an Fe-Cr-V alloy with 10% vanadium is presented. Investigations were carried out on the PBF-EB system Arcam A2X. Specimens and demonstrators are characterized by a three-phase microstructure with an Fe-rich matrix and VC and M7C3 reinforcements. The resulting microstructures were characterized by scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD). Furthermore, mechanical and physical properties were measured. A final field test was conducted to evaluate durability in use.
Investigation on the Deformation and Failure Characteristics of Concrete in Dynamic Splitting Tests
Authors: Xu Xuan , Chi Li-Yuan , Yang Jun , Lv Nao
Published: February 2022

The dynamic response behavior of concrete is constantly concerned because of seismic, impact and explosion events in the service of constructions. As a classic device for testing the dynamic mechanical properties of materials, the splitting Hopkinson pressure bar was used to carry out dynamic splitting tests on concrete in this paper. The variation of the dynamic tensile strength against the stress rate was fitted by the incubation time criterion. The full-field strain distribution on the observed surface of the specimen at the crack initiation stage was obtained by the digital image correlation (DIC) method. Morphological characteristics of the fragmentized process of concrete specimens in splitting processes were obtained by combining the image processing techniques and the FracPaQ. The size distribution of fragments of concrete specimens was obtained by sieving. The results show that the strain concentration zone and crack initiation appear along the loading direction through the center of the specimen. The secondary cracks initiated occurred at the contact end of the specimen, which expanded along the strain concentration zone and then interacted with the main crack. At the early stage of crack extension, the main crack dominates the normalized length of fracture traces in the horizontal direction. The normalized length of the vertical fracture trace increases with the main cracks opening width and the expansion of the secondary crack. The relationship between the length and angle of fracture traces in the dynamic splitting process of concrete conforms to the Gaussian function. Finally, the fragment sizes decrease with the stress rates of impact loads.
Investigation of Warpage for Multi-Die Fan-Out Wafer-Level Packaging Process
Authors: Chen Chuan , Su Meiying , Ma Rui , Zhou Yunyan , Li Jun , Cao Liqiang
Published: February 2022

This paper focuses on characterizing the evolution of warpage, effects of epoxy molding compound (EMC), and effects of carrier 2 (the second carrier in the process) of 12 inch RDL-first multi-die fan-out wafer-level packaging (FOWLP) during the manufacturing process. The linear viscoelasticity properties of EMC and polyimide (PI) were characterized using dynamic mechanical analysis (DMA) in the frequency domain at different temperatures., The elastic and viscoelastic model were used for PI and EMC, the finite element analyses (FEA) of the cured structure were carried out and the results were compared with the test results. The viscoelastic properties of the EMC in the FEA could predict the wafer warpage more accurately. The FEA and experiments were used to investigate the evolution of warpage. The molding had a great influence on the warpage. The effects of the EMC and carrier 2 were also investigated with FEA. The wafer warpage could be reduced by lowering the thickness of the EMC, increasing the thickness of carrier 2, and selecting EMC and carrier 2 with a matched coefficient of thermal expansion (CTE).
Enhanced Sinterability, Thermal Conductivity and Dielectric Constant of Glass-Ceramics with PVA and BN Additions
Authors: Arıbuğa Dilara , Akkaşoğlu Ufuk , Çiçek Buğra , Balcı-Çağıran Özge
Published: February 2022

With the rapid development of the microelectronics industry, many efforts have been made to improve glass-ceramics’ sinterability, thermal conductivity, and dielectric properties, which are essential components of electronic materials. In this study, low-alkali borosilicate glass-ceramics with PVA addition and glass-BN composites were prepared and successfully sintered at 770 °C. The phase composition, density, microstructure, thermal conductivity, and dielectric constant were investigated. It was shown that PVA addition contributes to the densification process of glass-ceramics (~88% relative density, with closed/open pores in the microstructure) and improves the thermal conductivity of glass material from 1.489 to 2.453 W/K.m. On the other hand, increasing BN addition improves microstructures by decreasing porosities and thus increasing relative densities. A glass-12 wt. % BN composite sample exhibited almost full densification after sintering and presented apparent and open pores of 2.6 and 0.08%, respectively. A high thermal conductivity value of 3.955 W/K.m and a low dielectric constant of 3.00 (at 5 MHz) were observed in this material. Overall, the resulting glass-ceramic samples showed dielectric constants in the range of 2.40–4.43, providing a potential candidate for various electronic applications.
Influence of Anomalous Changes in the Crystal Structure on the Transport Properties of YbNi1−xCuxAl Series of Alloys
Authors: Pupo Daniel Rojas , Gandra Flávio Guimarães , Barquín Luis Fernández
Published: February 2022

Results of the transport properties of the YbNi1−xCuxAl (x = 0, 0.2, 0.5, 0.8 and 1.0) series of alloys are reported. The previous analysis of X-ray diffraction patterns indicates that all compounds crystallize in the hexagonal ZrNiAl structure with a linear behavior of the unit cell volume as a function of the Cu concentration (x). This is not found in the unit cell parameters, showing a discontinuity between x = 0.5 and 0.8. Such discontinuities affect the behavior of the electrical resistivity, in which the position of the minimum temperature changes from 95 K to 175 K, and a rise in the low temperature slope in the magnetic contribution (with -lnT dependence) from 21 μΩcm to 212 μΩcm is observed. In addition, the electronic coefficient of the specific heat increases almost twofold from 125 mJ/mol·K2 (x = 0.5) to 246 mJ/mol·K2 (x = 0.8). These changes are attributed to the variation of the distance between Yb and transition metals (Ni and Cu) along the series and the different electronic properties of the transition metals (Ni and Cu).