bluuebunny/crossref_metadata_2025 huggingface dataset:
Manifestation of Headache Affecting Quality of Life in Long COVID Patients
Authors: Fujita Kana , Otsuka Yuki , Sunada Naruhiko , Honda Hiroyuki , Tokumasu Kazuki , Nakano Yasuhiro , Sakurada Yasue , Obika Mikako , Hagiya Hideharu , Otsuka Fumio
Published: May 2023

Objectives: The present study aimed to elucidate the characteristics of long COVID patients with headaches. Methods: A single-center retrospective observational study was performed for long COVID outpatients who visited our hospital from 12 February 2021 to 30 November 2022. Results: A total of 482 long COVID patients, after excluding 6, were divided into two groups: the Headache group of patients with complaints of headache (113 patients: 23.4%) and the remaining Headache-free group. Patients in the Headache group were younger (median age: 37 years) than patients in the Headache-free group (42 years), while the ratio of females (56%) in the Headache group was nearly the same as that in the Headache-free group (54%). The proportion of patients in the Headache group who were infected in the Omicron-dominant phase (61%) was larger than the proportions of patients infected in the Delta (24%) and preceding (15%) phases, and that trend was significantly different from the trend in the Headache-free group. The duration before the first visit for long COVID was shorter in the Headache group (71 days) than in the Headache-free group (84 days). The proportions of patients in the Headache group with comorbid symptoms, including general fatigue (76.1%), insomnia (36.3%), dizziness (16.8%), fever (9.7%), and chest pain (5.3%) were larger than the proportions of patients in the Headache-free group, whereas blood biochemical data were not significantly different between the two groups. Interestingly, patients in the Headache group had significant deteriorations of scores indicating depression and scores for quality of life and general fatigue. In multivariate analysis, headache, insomnia, dizziness, lethargy, and numbness were shown to be involved in the quality of life (QOL) of long COVID patients. Conclusions: The manifestation of headaches related to long COVID was found to have a significant impact on social and psychological activities. Alleviation of headaches should be a priority for the effective treatment of long COVID.
Lipoprotein(a) Does Not Predict Thrombotic Events and In-Hospital Outcomes in Patients with COVID-19
Authors: Bianconi Vanessa , Mannarino Massimo R. , Ramondino Federica , Fusaro Jessica , Giglioni Francesco , Braca Marco , Ricciutelli Federica , Lombardini Rita , Paltriccia Rita , Greco Alessia , Lega Iliana C. , Pirro Matteo
Published: May 2023

The prothrombotic and proinflammatory properties of lipoprotein(a) (Lp(a)) have been hypothesized to play a role in the pathogenesis of severe COVID-19; however, the prognostic impact of Lp(a) on the clinical course of COVID-19 remains controversial. This study aimed to investigate whether Lp(a) may be associated with biomarkers of thrombo-inflammation and the occurrence of thrombotic events or adverse clinical outcomes in patients hospitalized for COVID-19. We consecutively enrolled a cohort of patients hospitalized for COVID-19 and collected blood samples for Lp(a) assessment at hospital admission. A prothrombotic state was evaluated through D-dimer levels, whereas a proinflammatory state was evaluated through C-reactive protein (CRP), procalcitonin, and white blood cell (WBC) levels. Thrombotic events were marked by the diagnosis of deep or superficial vein thrombosis (DVT or SVT), pulmonary embolism (PE), stroke, transient ischemic attack (TIA), acute coronary syndrome (ACS), and critical limb ischemia (CLI). The composite clinical end point of intensive care unit (ICU) admission/in-hospital death was used to evaluate adverse clinical outcomes. Among 564 patients (290 (51%) men, mean age of 74 ± 17 years) the median Lp(a) value at hospital admission was 13 (10–27) mg/dL. During hospitalization, 64 (11%) patients were diagnosed with at least one thrombotic event and 83 (15%) patients met the composite clinical end point. Lp(a), as either a continuous or categorical variable, was not associated with D-dimer, CRP, procalcitonin, and WBC levels (p > 0.05 for all correlation analyses). In addition, Lp(a) was not associated with a risk of thrombotic events (p > 0.05 for multi-adjusted odds ratios) nor with a risk of adverse clinical outcomes (p > 0.05 for multi-adjusted hazard ratios). In conclusion, Lp(a) does not influence biomarkers of plasma thrombotic activity and systemic inflammation nor has any impact on thrombotic events and adverse clinical outcomes in patients hospitalized for COVID-19.
Prognostic Factors in Staged Bilateral Total Knee Arthroplasty—A Retrospective Case Series Analysis
Authors: Kazubski Krystian , Tomczyk Łukasz , Bobiński Andrzej , Morasiewicz Piotr
Published: May 2023

Background: Bilateral osteoarthritis of the knee is an indication for a bilateral total knee replacement (TKR) procedure. The goal of our study was to assess the sizes of the implants used during the first and second stages of TKR procedures in order to compare their size and identify the prognostic factors for the second procedure. Methods: We evaluated 44 patients who underwent staged bilateral TKR procedures. We assess the following prognostic factors from the first and second surgery: duration of anesthesia, femoral component size, tibial component size, duration of hospital stay, tibial polyethylene insert size, and the number of complications. Results: All assessed prognostic factors did not differ statistically between the first and second TKR. A strong correlation was found between the size of femoral components and the size of tibial components used during the first and second total knee arthroplasty. The mean duration of the hospital stay associated with the first TKR surgery was 6.43 days, whereas the mean duration of the second hospital stay was 5.5 days (p = 0.211). The mean sizes of the femoral components used during the first and second procedures were 5.43 and 5.2, respectively (p = 0.54). The mean sizes of the tibial components used during the first and second TKR procedures were 5.36 and 5.25, respectively (p = 0.382). The mean sizes of the tibial polyethylene inserts used during the first and second procedures were 9.45 and 9.34 (p = 0.422), respectively. The mean duration of anesthesia during the first and second knee arthroplasty was 117.04 min and 118.06 min, respectively (p = 0.457). The mean rates of recorded complications associated with the first and second TKR procedures were 0.13 and 0.06 per patient (p = 0.371). Conclusions: We observed no differences between the two stages of treatment in terms of all analyzed parameters. We observed a strong correlation between the size of femoral components used during the first and second total knee arthroplasty. We noted a strong correlation between the size of tibial components used during the first and second procedure. Slightly weaker prognostic factors include the number of complications, duration of anesthesia and tibial polyethylene insert size.
Development of Salmon Sperm DNA/Regenerated Silk Bio-Based Films for Biomedical Studies on Human Keratinocyte HaCaT Cells under Solar Spectrum
Authors: Ceccarini Maria Rachele , Ripanti Francesca , Raggi Veronica , Paciaroni Alessandro , Petrillo Caterina , Comez Lucia , Donato Kevin , Bertelli Matteo , Beccari Tommaso , Valentini Luca
Published: May 2023

In this study, we fabricated adhesive patches from silkworm-regenerated silk and DNA to safeguard human skin from the sun’s rays. The patches are realized by exploiting the dissolution of silk fibers (e.g., silk fibroin (SF)) and salmon sperm DNA in formic acid and CaCl2 solutions. Infrared spectroscopy is used to investigate the conformational transition of SF when combined with DNA; the results indicated that the addition of DNA provides an increase in the SF crystallinity. UV–Visible absorption and circular dichroism spectroscopy showed strong absorption in the UV region and the presence of B-form of DNA once dispersed in the SF matrix, respectively. Water absorption measurements as well as thermal dependence of water sorption and thermal analysis, suggested the stability of the fabricated patches. Biological results on cellular viability (MTT assay) of keratinocyte HaCaT cells after exposures to the solar spectrum showed that both SF and SF/DNA patches are photo-protective by increasing the cellular viability of keratinocytes after UV component exposure. Overall, these SF/DNA patches promise applications in wound dressing for practical biomedical purposes.
Photobiomodulation and Inorganic Bovine Bone in Guided Bone Regeneration: Histomorphometric Analysis in Rats
Authors: Freitas Nicole Rosa de , Guerrini Luísa Belluco , Esper Luis Augusto , Sbrana Michyele Cristhiane , Santos Caroline Chepernate Vieira dos , Almeida Ana Lúcia Pompéia Fraga de
Published: May 2023

The objective of this study was to evaluate the efficacy of photobiomodulation in the bone regeneration of critical-sized defects (CSD) filled with inorganic bovine bone associated or not with collagen membranes. The study has been conducted on 40 critical defects in the calvaria of male rats, divided into four experimental groups (n = 10): (1) DBBM (deproteinized bovine bone mineral); (2) GBR (DBBM+collagen membrane); (3) DBBM+P (DBBM+photobiomodulation); and (4) GBR+P (GBR+photobiomodulation). At 30 days postoperative, the animals were euthanized, and after the tissue had been processed, histological, histometric, and statistical analyses were performed. The analyses have taken into account newly formed bone area (NBA), linear bone extension (LBE), and residual particle area (RPA) as variables. The Kruskal-Wallis test has been performed, followed by the Dwass-Steel-Critchlow-Fligner test for comparison between groups (p < 0.05). When the DBBM+P group was compared to the DBBM group, it was possible to observe significant statistical differences in all the variables analyzed (p < 0.05). The application of photobiomodulation in guided bone regeneration (GBR+P) has shown a decrease in the median value for the RPA variable (26.8) when compared to the GBR group (32.4), with a significant statistical difference; however, for NBA and LBE, the therapy has not provided significant results.
A Parametric Study on the Interconnector of Solid Oxide Electrolysis Cells for Co-Electrolysis of Water and Carbon Dioxide
Authors: Li Shian , Yang Zhi , Shen Qiuwan , Yang Guogang
Published: May 2023

The shipping industry is trying to use new types of fuels to meet strict pollutant emission regulations and carbon emission reduction targets. Hydrogen is one of the options for alternative fuels used in marine applications. Solid oxide electrolysis cell (SOEC) technology can be used for hydrogen production. When water and carbon dioxide are provided to SOECs, hydrogen and carbon monoxide are produced. The interconnector of SOECs plays a vital role in cell performance. In this study, a 3D mathematical model of cathode-supported planar SOECs is developed to investigate the effect of interconnector rib width on the co-electrolysis of water and carbon dioxide in the cell. The model validation is carried out by comparing the numerical results with experimental data in terms of a polarization curve. The rib width is varied from 0.2 mm to 0.8 mm with an interval of 0.1 mm. It is found that the cell voltage is decreased and then increased as the rib width increases. When the current density is 1 A/cm2, the voltages of SOECs with rib widths of 0.2 mm, 0.6 mm, and 0.8 mm are 1.272 V, 1.213 V, and 1.221 V, respectively. This demonstrates that the best performance is provided by the SOEC with a rib width of 0.6 mm. In addition, the local transport processes of SOECs with different rib widths are presented and compared in detail. This study can provide guidelines for the design of interconnectors of SOECs.
Source Apportionment of Soil Heavy Metal(Loid)s in Farmland Using Diverse Models: A Comparative Assessment in the Yellow River Delta
Authors: Huang Wei , Wang Shuhuan , Wang Lu , Song Yingqiang , Zhu Yue , Yang Hao , Xie Yingkai , Hu Yueming
Published: May 2023

The rapid development of industrialization and urbanization has posed serious challenges for coastal farmland ecosystems. Source apportionment of soil heavy metals is an effective way for the detection of non-point source pollution in farmland to help support the high-quality development of coastal agriculture. To this end, 113 surface soil samples were collected in the coastal delta of China, and the contents of As, Cd, Cr, Cu, Ni, Pb, and Zn were determined. A variety of models were integrated to apportion the source of soil heavy metals, including positive matrix factorization (PMF), geographical detector (GD), eXtreme gradient boosting (XGBoost), and structural equation modeling (SEM). The result of PMF models revealed that there was collinearity between various heavy metals, and the same heavy metal may have a mixed source. The XGBoost model analysis indicated that there were significant non-linear relationships between soil heavy metals and source factors. A synergy between air quality and human activity factors was the key source of heavy metal that entered the study area, based on the results of the GD. Furthermore, the input path effect of heavy metals in the soil of the study area was quantified by SEM. The balance of evidence from the above models showed that air quality (SO2 and NO2) and factories in the study area had the greatest impacts on Cd, Cr, and Zn. Natural sources were dominant for Pb, while As, Cu, and Ni were contributed by soil parent material and factories. The above results led to the conclusion that there was a cycle path in the study area that continuously promoted the migration and accumulation of heavy metals in farmland soil; that is, the heavy metals discharged during oil exploitation and smelting entered the atmosphere and then accumulated in the farmland soil through precipitation, atmospheric deposition, and other paths. In this study, it is shown that a variety of models can be used to more comprehensively assess the sources of soil heavy metals. This approach can provide effective support for the rapid prevention and decision-making management of soil heavy metal pollution in coastal areas.
Going over Fungal Allergy: Alternaria alternata and Its Allergens
Authors: Abel-Fernández Eva , Martínez María José , Galán Tania , Pineda Fernando
Published: May 2023

Fungal allergy is the third most frequent cause of respiratory pathologies and the most related to a poor prognosis of asthma. The genera Alternaria and Cladosporium are the most frequently associated with allergic respiratory diseases, with Alternaria being the one with the highest prevalence of sensitization. Alternaria alternata is an outdoor fungus whose spores disseminate in warm and dry air, reaching peak levels in temperate summers. Alternaria can also be found in damp and insufficiently ventilated houses, causing what is known as sick building syndrome. Thus, exposure to fungal allergens can occur outdoors and indoors. However, not only spores but also fungal fragments contain detectable amounts of allergens and may function as aeroallergenic sources. Allergenic extracts of Alternaria hyphae and spores are still in use for the diagnosis and treatment of allergic diseases but are variable and insufficiently standardised, as they are often a random mixture of allergenic ingredients and casual impurities. Thus, diagnosis of fungal allergy has been difficult, and knowledge about new fungal allergens is stuck. The number of allergens described in Fungi remains almost constant while new allergens are being found in the Plantae and Animalia kingdoms. Given Alt a 1 is not the unique Alternaria allergen eliciting allergy symptoms, component-resolved diagnosis strategies should be applied to diagnose fungal allergy. To date, twelve A. alternata allergens are accepted in the WHO/IUIS Allergen Nomenclature Subcommittee, many of them are enzymes: Alt a 4 (disulfide isomerase), Alt a 6 (enolase), Alt a 8 (mannitol de-hydrogenase), Alt a 10 (aldehyde dehydrogenase), Alt a 13 (glutathione-S-transferase) and Alt a MnSOD (Mn superoxide dismutase), and others have structural and regulatory functions such as Alt a 5 and Alt a 12, Alt a 3, Alt a 7. The function of Alt a 1 and Alt a 9 remains unknown. Other four allergens are included in other medical databases (e.g., Allergome): Alt a NTF2, Alt a TCTP, and Alt a 70 kDa. Despite Alt a 1 being the A. alternata major allergen, other allergens, such as enolase, Alt a 6 or MnSOD, Alt a 14 have been suggested to be included in the diagnosis panel of fungal allergy.
Fungal Infections in the ICU during the COVID-19 Pandemic in Mexico
Authors: Roman-Montes Carla M. , Bojorges-Aguilar Saul , Corral-Herrera Ever Arturo , Rangel-Cordero Andrea , Díaz-Lomelí Paulette , Cervantes-Sanchez Axel , Martinez-Guerra Bernardo A. , Rajme-López Sandra , Tamez-Torres Karla María , Martínez-Gamboa Rosa Areli , González-Lara Maria Fernanda , Ponce-de-Leon Alfredo , Sifuentes-Osornio José
Published: May 2023

Background: Invasive Fungal Infections (IFI) are emergent complications of COVID-19. In this study, we aim to describe the prevalence, related factors, and outcomes of IFI in critical COVID-19 patients. Methods: We conducted a nested case–control study of all COVID-19 patients in the intensive care unit (ICU) who developed any IFI and matched age and sex controls for comparison (1:1) to evaluate IFI-related factors. Descriptive and comparative analyses were made, and the risk factors for IFI were compared versus controls. Results: We found an overall IFI prevalence of 9.3% in COVID-19 patients in the ICU, 5.6% in COVID-19-associated pulmonary aspergillosis (CAPA), and 2.5% in invasive candidiasis (IC). IFI patients had higher SOFA scores, increased frequency of vasopressor use, myocardial injury, and more empirical antibiotic use. CAPA was classified as possible in 68% and 32% as probable by ECMM/ISHAM consensus criteria, and 57.5% of mortality was found. Candidemia was more frequent for C. parapsilosis Fluconazole resistant outbreak early in the pandemic, with a mortality of 28%. Factors related to IFI in multivariable analysis were SOFA score > 2 (aOR 5.1, 95% CI 1.5–16.8, p = 0.007) and empiric antibiotics for COVID-19 (aOR 30, 95% CI 10.2–87.6, p = <0.01). Conclusions: We found a 9.3% prevalence of IFIs in critically ill patients with COVID-19 in a single center in Mexico; factors related to IFI were associated with higher SOFA scores and empiric antibiotic use for COVID-19. CAPA is the most frequent type of IFI. We did not find a mortality difference.
Observations on Pluteaceae in Vietnam: Four New Species and New Records of Pluteus
Authors: Malysheva Ekaterina , Popov Eugene , Morozova Olga , Dudka Vasily , Pham Thi Ha Giang , Malysheva Vera
Published: May 2023

Eighteen specimens of Pluteus collected from the tropical forests of Vietnam were studied using morphological and molecular approaches. Pluteus podospilloides, P. semibulbosus, P. chrysaegis and P. septocystidiatus are registered as additional or new records for Vietnam. Four species (P. conformis, P. lucidus, P. subroseus, and P. ornatus) are proposed as new to science, and several other collections (Pluteus sp. 1, P. aff. septocystidiatus, P. aff. pauperculus and P. cf. velutinus) are given an inconclusive taxonomic status for now. The taxonomic positions of all specimens were confirmed using DNA data (nrITS and tef1). Descriptions of the macro- and microscopic features of the studied collections with a discussion of similar taxa are given.
Systematic Literature Review and Early Benefit of Cochlear Implantation in Two Pediatric Auditory Neuropathy Cases
Authors: Keintzel Thomas , Raffelsberger Tobias , Niederwanger Lisa , Gundacker Gina , Rasse Thomas
Published: May 2023

Approximately 1 in 10 children with hearing loss is affected by auditory neuropathy spectrum disorder (ANSD). People who have ANSD usually have great difficulty understanding speech or communicating. However, it is possible for these patients to have audiograms that may indicate profound hearing loss up to normal hearing. This disorder is prognosed with positive, intact or present otoacoustic emissions (OAE) and/or cochlear microphonics (CM) as well as abnormal or absent auditory brainstem responses (ABR). Treatment methods include conventional hearing aids as well as cochlear implants. Cochlear implants (CI) usually promise better speech understanding for ANSD patients. We performed a systematic literature review aiming to show what improvements can effectively be achieved with cochlear implants in children with ANSD and compare this with our experience with two cases of ANSD implanted at our clinic. The retrospective review of two young CI patients diagnosed with ANSD during infancy demonstrated improvements over time in speech development communicated by their parents.
Consumption of Healthcare Services in the United States: The Impact of Health Insurance
Authors: Narita Raluca Elena
Published: May 2023

Over the past few decades, healthcare expenditures in the United States have increased due to a variety of different factors. Depending on their insurance plans, Americans have varying levels of health insurance coverage and may need to make co-payments or pay fully for specific health services. According to multiple studies, health insurance does appear to increase the utilization of healthcare services, except emergency services. Demographic factors such as age, citizenship, and race/ethnicity, as well as the type of health service demanded, all appear to influence the consumption of healthcare in the United States. However, many existing studies conducted in this area are not experimental or randomized, which may result in a lack of validity of the estimated relationship between insurance and healthcare utilization due to confounding variables. A new experimental study, similar to the RAND HIE study, is needed to provide insight into the current relationships between insurance and healthcare utilization, taking into consideration changes in legislation.
Assessment of Urban Ecological Resilience Based on PSR Framework in the Pearl River Delta Urban Agglomeration, China
Authors: Zhang Qiongrui , Huang Tao , Xu Songjun
Published: May 2023

Studying resilience provides an opportunity to address a range of urban environmental problems. However, existing studies pay little attention to urban ecological resilience (UER), and the system of assessing urban resilience pays little attention to the process attribute of resilience. This study focuses on UER and constructs an evaluation framework based on the pressure _state _response (PSR) framework. The ‘pressure’ indicator morphological resilience (MR) is evaluated using source _sink landscape theory. The ‘state’ indicator density resilience (DR) is evaluated using the ratio of ecological carrying capacity to ecological footprint. The ‘response’ indicator uses indicators of economic structure, vitality, and innovation for evaluation. We found that the MR and DR of the study area in 2020 showed a spatial layout of low in the central area and high in the peripheral areas, while the high-value ER area was in the central part. The average district and county MR was 1.44, DR was between 0.003 and 1.975, and ER was 0.32; overall, ER and MR are better in the study area, but DR is worse. The spatial layout of comprehensive UER was found to be low in the middle and high in the periphery of the study area. Some areas with low MR and DR have high UER, which verifies the compensation effect of ER on urban ecology. This study provides a new method for assessing UER, and the findings can provide useful information for urban planning.
Regional Citrate Anticoagulation in Continuous Renal Replacement Therapy: Is Metabolic Fear the Enemy of Logic? A Systematic Review and Meta-Analysis of Randomised Controlled Trials
Authors: Jacobs Rita , Verbrugghe Walter , Dams Karolien , Roelant Ella , Couttenye Marie Madeleine , Devroey Dirk , Jorens Philippe
Published: May 2023

Background: Anticoagulation is recommended to maintain the patency of the circuit in continuous renal replacement therapy (CRRT). However, anticoagulation-associated complications can occur. We performed a systematic review and meta-analysis to compare the efficacy and safety of citrate anticoagulation to heparin anticoagulation in critically ill patients treated with CRRT. Methods: Randomised controlled trials (RCTs) evaluating the safety and efficacy of citrate anticoagulation and heparin in CRRT were included. Articles not describing the incidence of metabolic and/or electrolyte disturbances induced by the anticoagulation strategy were excluded. The PubMed, Embase, and MEDLINE electronic databases were searched. The last search was performed on 18 February 2022. Results: Twelve articles comprising 1592 patients met the inclusion criteria. There was no significant difference between the groups in the development of metabolic alkalosis (RR = 1.46; (95% CI (0.52–4.11); p = 0.470)) or metabolic acidosis (RR = 1.71, (95% CI (0.99–2.93); p = 0.054)). Patients in the citrate group developed hypocalcaemia more frequently (RR = 3.81; 95% CI (1.67–8.66); p = 0.001). Bleeding complications in patients randomised to the citrate group were significantly lower than those in the heparin group (RR 0.32 (95% CI (0.22–0.47); p < 0.0001)). Citrate showed a significantly longer filter lifespan of 14.52 h (95% CI (7.22–21.83); p < 0.0001), compared to heparin. There was no significant difference between the groups for 28-day mortality (RR = 1.08 (95% CI (0.89–1.31); p = 0.424) or 90-day mortality (RR 0.9 (95% CI (0.8–1.02); p = 0.110). Conclusion: regional citrate anticoagulation is a safe anticoagulant for critically ill patients who require CRRT, as no significant differences were found in metabolic complications between the groups. Additionally, citrate has a lower risk of bleeding and circuit loss than heparin.
Laryngotracheal Complications after Intubation for COVID-19: A Multicenter Study
Authors: Hernández-García Estefanía , Hernández-Sandemetrio Rosa , Quintana-Sanjuás Ana , Zapater-Latorre Enrique , González-Herranz Ramón , Sanz Lorena , Reboll Rosa , Pallarés-Martí Beatriz , Ollé-Moliner Montserrat , Martínez-Pascual Paula , Gotxi Itziar , Chacón-Uribe Araly , Plaza Guillermo
Published: May 2023

Many of the patients with COVID-19 have suffered respiratory distress requiring prolonged endotracheal intubation (ETI) resulting in laryngotracheal complication with an impact on breathing, phonation, and swallowing. Our aim is to describe laryngeal injuries diagnosed after ETI in patients with COVID-19 in a multicentre study. Methods: A prospective descriptive observational study was conducted from January 2021 to December 2021, including COVID-19 patients with laryngeal complications due to ETI diagnosed in several Spanish hospitals. We analyzed the epidemiological data, previous comorbidities, mean time to ICU admission and ETI, need for tracheostomy, mean time on invasive mechanical ventilation until tracheostomy or weaning, mean time in ICU, type of residual lesions, and their treatment. Results: We obtained the collaboration of nine hospitals during the months of January 2021 to December 2021. A total of 49 patients were referred. Tracheostomy was performed in 44.9%, being late in most cases (more than 7–10 days). The mean number of days of ETI until extubation was 17.63 days, and the main post-intubation symptoms were dysphonia, dyspnea, and dysphagia, in 87.8%, 34.7%, and 42.9%, respectively. The most frequent injury was altered laryngeal mobility, present in 79.6%. Statistically, there is a greater amount of stenosis after late ETI and after delayed tracheostomy, not observing the data with the immobility alterations. Conclusion: The mean number of days of ETI was long, according to the latest guidelines, with the need for several cycles of pronation. This long ETI may have had an impact on the increase of subsequent laryngeal sequelae, such as altered laryngeal mobility or stenosis.
Tribological Study on Photocatalysis-Assisted Chemical Mechanical Polishing of SiC
Authors: Lee Hyunseop
Published: May 2023

Silicon carbide (SiC) is widely used as a power semiconductor substrate material, even if it takes a large amount of processing time to secure an appropriate surface as a wafer for devices after chemical mechanical polishing (CMP). Therefore, studies on SiC CMP have focused on shortening the processing time by increasing material removal efficiency. Among the methods of SiC CMP that have been widely studied recently, the photocatalysis-assisted CMP (PCMP) method is known to efficiently increase the material removal rate (MRR) of SiC under UV light and photocatalysts. However, a limited number of comparative studies have been conducted on PCMP from a tribology perspective. In this article, a comparative study was conducted from a tribology perspective on CMP, mixed abrasive slurry CMP (MAS CMP), and PCMP. The experimental results demonstrated that SiC PCMP has higher friction and processing temperature than MAS CMP and general CMP, which may be caused by photocatalytic oxidation and the TiO2 particles used as photocatalysts.
Two-Way PBM–Euler Model for Gas and Liquid Flow in the Ladle
Authors: Zhang Han , Lei Hong , Ding Changyou , Chen Shifu , Xiao Yuanyou , Li Qiang
Published: May 2023

Ladle metallurgy is an important steelmaking technology in high-quality steel production. The blowing of argon at the ladle bottom has been applied in ladle metallurgy for several decades. Until now, the issue of breakage and coalescence among bubbles was still far from being solved. In order to have a deep insight into the complex process of fluid flow in the gas-stirred ladle, the Euler–Euler model and population balance model (PBM) are coupled to investigate the complex fluid flow in the gas-stirred ladle. Here, the Euler–Euler model is applied to predict the two-phase flow, and PBM is applied to predict the bubble and size distribution. The coalescence model, which considers turbulent eddy and bubble wake entrainment, is taken into account to determine the evolution of the bubble size. The numerical results show that if the mathematical model ignores the breakage of bubbles, the mathematical model gives the wrong bubble distribution. For bubble coalescence in the ladle, turbulent eddy coalescence is the main mode, and wake entrainment coalescence is the minor mode. Additionally, the number of the bubble-size group is a key parameter for describing the bubble behavior. The size group number 10 is recommended to predict the bubble-size distribution.
Surface Modification of CaCO3 by Ultrasound-Assisted Titanate and Silane Coupling Agents
Authors: Cheng Peng , Yang Lei , Xie Yuxiong , Liu Yu
Published: May 2023

Calcium carbonate (CaCO3) is a widely used inorganic powder, but its industrial applications are limited by its hydrophilicity and oleophobicity. Surface modification of CaCO3 can improve its dispersion and stability in organic materials and further improve its potential value. In this study, CaCO3 particles were modified with silane coupling agent (KH550) and titanate coupling agent (HY311) combined with ultrasonication. The oil absorption value (OAV), activation degree (AG), and sedimentation volume (SV) were employed to evaluate the modification performance. The results showed that the modification effect of HY311 on CaCO3 was better than that of KH550, and ultrasonic treatment played an auxiliary role. Based on response surface analysis, the optimal modification conditions were determined as follows: the HY311 dosage was 0.7%, the KH550 dosage was 0.7%, and ultrasonic time was 10 min. The OAV, AG, and SV of modified CaCO3 under these conditions were 16.65 g DOP/100 g, 99.27%, and 0.65 mL/g, respectively. The SEM, FTIR, XRD and thermal gravimetric analyses indicated successful coating of HY311 and KH550 coupling agents on the surface of CaCO3. The optimization of the dosages of two coupling agents and ultrasonic time improved the modification performance significantly.
Comparative Evaluation of Flexural Toughness of Steel Fiber-Reinforced Concrete Beams
Authors: Yun Hyun-Do , Choi Ki-Bong , Choi Won-Chang
Published: May 2023

Specifications are available to quantify flexural performance of steel-fiber reinforced concrete beams with several parameters. Each specification provides different results. This study comparatively evaluates existing flexural beam test standards that are used to evaluate the flexural toughness of SFRC beam specimens. Two standards, EN-14651 and ASTM C1609, were followed to test SFRC beams under the three-point bending test (3PBT) and the four-point bending test (4PBT), respectively. Both normal tensile strength steel fiber (1200 MPa) and high tensile strength steel fiber (1500 MPa) in high-strength concrete were considered in this study. The reference parameters recommended in the two standards, which include equivalent flexural strength, residual strength, energy absorption capacity, and flexural toughness, were compared based on the tensile strength (normal or high) of the steel fiber in high-strength concrete. The 3PBT and 4PBT results indicate that both standard test methods yield similar results to quantify the flexural performance of SFRC specimens. However, unintended failure modes were observed for both standard test methods. The adopted correlation model shows that the flexural performance of SFRC is similar for 3PBTs and 4PBTs, but the residual strength obtained from the 3PBTs tends to be greater than that obtained from 4PBTs with an increase in the tensile strength of steel fiber.
Research Progress on Microstructure Evolution and Strengthening-Toughening Mechanism of Mg Alloys by Extrusion
Authors: Zheng Yaqi , Zhang Yuan , Liu Yun , Tian Yaqiang , Zheng Xiaoping , Chen Liansheng
Published: May 2023

Magnesium and magnesium-based alloys are widely used in the transportation, aerospace and military industries because they are lightweight, have good specific strength, a high specific damping capacity, excellent electromagnetic shielding properties and controllable degradation. However, traditional as-cast magnesium alloys have many defects. Their mechanical and corrosion properties cause difficulties in meeting application requirements. Therefore, extrusion processes are often used to eliminate the structural defects of magnesium alloys, and to improve strength and toughness synergy as well as corrosion resistance. This paper comprehensively summarizes the characteristics of extrusion processes, elaborates on the evolution law of microstructure, discusses DRX nucleation, texture weakening and abnormal texture behavior, discusses the influence of extrusion parameters on alloy properties, and systematically analyzes the properties of extruded magnesium alloys. The strengthening mechanism is comprehensively summarized, the non-basal plane slip, texture weakening and randomization laws are comprehensively summarized, and the future research direction of high-performance extruded magnesium alloys is prospected.
Analytical Review of Geopolymer Concrete: Retrospective and Current Issues
Authors: Meskhi Besarion , Beskopylny Alexey N. , Stel’makh Sergey A. , Shcherban’ Evgenii M. , Mailyan Levon R. , Shilov Alexandr A. , El’shaeva Diana , Shilova Karolina , Karalar Memduh , Aksoylu Ceyhun , Özkılıç Yasin Onuralp
Published: May 2023

The concept of sustainable development provides for the search for environmentally friendly alternatives to traditional materials and technologies that would reduce the amount of CO2 emissions into the atmosphere, do not pollute the environment, and reduce energy costs and the cost of production processes. These technologies include the production of geopolymer concretes. The purpose of the study was a detailed in-depth analytical review of studies of the processes of structure formation and properties of geopolymer concretes in retrospect and the current state of the issue. Geopolymer concrete is a suitable, environmentally friendly and sustainable alternative to concrete based on ordinary Portland cement (OPC) with higher strength and deformation properties due to its more stable and denser aluminosilicate spatial microstructure. The properties and durability of geopolymer concretes depend on the composition of the mixture and the proportions of its components. A review of the mechanisms of structure formation, the main directions for the selection of compositions and processes of polymerization of geopolymer concretes has been made. The technologies of combined selection of the composition of geopolymer concrete, production of nanomodified geopolymer concrete, 3D printing of building structures from geopolymer concrete, and monitoring the state of structures using self-sensitive geopolymer concrete are considered. Geopolymer concrete with the optimal ratio of activator and binder has the best properties. Geopolymer concretes with partial replacement of OPC with aluminosilicate binder have a denser and more compact microstructure due to the formation of a large amount of calcium silicate hydrate, which provides improved strength, durability, less shrinkage, porosity and water absorption. An assessment of the potential reduction in greenhouse gas emissions from the production of geopolymer concrete compared to the production of OPC has been made. The potential of using geopolymer concretes in construction practice is assessed in detail.
Characterization of Zn-Mg-Sr Type Soldering Alloy and Study of Ultrasonic Soldering of SiC Ceramics and Cu-SiC Composite
Authors: Kolenak Roman , Pluhar Alexej , Drapala Jaromir , Babincova Paulina , Pasak Matej
Published: May 2023

The aim of the research was to characterize the soldering alloy type Zn-Mg-Sr and direct the soldering of SiC ceramics with Cu-SiC-based composite. It was investigated whether the proposed composition of the soldering alloy was appropriate for soldering those materials at the defined conditions. For the determination of the solder melting point, TG/DTA analysis was applied. The Zn-Mg system is of the eutectic type with a reaction temperature of 364 °C. The effect of strontium on the phase transformation was minimal, owing to its lower content. The microstructure of the soldering alloy type Zn3Mg1.5Sr is formed of a very fine eutectic matrix containing segregated phases of strontium—SrZn13 and magnesium—MgZn2 and Mg2Zn11. The average tensile strength of the solder is 98.6 MPa. The tensile strength was partially increased by solder alloying with magnesium and strontium. The SiC/solder joint was formed due to the distribution of magnesium from the solder to the boundary with the ceramics at the formation of a phase. Owing to soldering in air, oxidation of the magnesium took place and the oxides formed were combined with the silicon oxides that remained on the surface of the ceramic material—SiC. Thus, a strong bond based on oxygen was obtained. An interaction between the liquid zinc solder and the copper matrix of the composite substrate took place at the formation of a new phase—γCu (Cu5Zn8). The shear strength was measured on several ceramic materials. The average shear strength of the combined SiC/Cu-SiC joint fabricated with Zn3Mg1.5Sr solder was 62 MPa. When soldering similar ceramic materials mutually, a shear strength of as much as around 100 MPa was observed.
Multi-Scale Microstructural Tailoring and Associated Properties of Press-Hardened Steels: A Review
Authors: Cheng Zhuo , Gao Mengjie , Liu Jinyue , Wang Shuize , Wu Guilin , Gao Junheng , Wu Honghui , Mao Xinping
Published: May 2023

High-strength press-hardened steels (PHS) are highly desired in the automotive industry to meet the requirement of carbon neutrality. This review aims to provide a systematic study of the relationship between multi-scale microstructural tailoring and the mechanical behavior and other service performance of PHS. It begins with a brief introduction to the background of PHS, followed by an in-depth description of the strategies used to enhance their properties. These strategies are categorized into traditional Mn-B steels and novel PHS. For traditional Mn-B steels, extensive research has verified that the addition of microalloying elements can refine the microstructure of PHS, resulting in improved mechanical properties, hydrogen embrittlement resistance, and other service performance. In the case of novel PHS, recent progress has principally demonstrated that the novel composition of steels coupling with innovative thermomechanical processing can obtain multi-phase structure and superior mechanical properties compared with traditional Mn-B steels, and their effect on oxidation resistance is highlighted. Finally, the review offers an outlook on the future development of PHS from the perspective of academic research and industrial applications.
Quality of the Ceramic and Ni-Cr Alloy Joint after Al2O3 Abrasive Blasting
Authors: Klimek Leszek , Wołowiec-Korecka Emilia , Czepułkowska-Pawlak Weronika , Kula Zofia
Published: May 2023

The purpose of this in vitro study was to determine the effect of airborne-particle abrasion process parameters on the strength of the Ni-Cr alloy–ceramic bond. One hundred and forty-four Ni-Cr disks were airborne-particle abraded with 50, 110 and 250 µm Al2O3 at a pressure of 400 and 600 kPa. After treatment, the specimens were bonded to dental ceramics by firing. The strength of the metal–ceramic bond was determined using the shear strength test. The results were analyzed with three-way analysis of variance (ANOVA) and the Tukey honest significant difference (HSD) test (α = 0.05). The examination also considered the thermal loads (5000 cycles, 5–55 °C) to which the metal–ceramic joint is subjected during exploitation. There is a close correlation between the strength of the Ni-Cr alloy–dental ceramic joint and the alloy roughness parameters after abrasive blasting: Rpk (reduced peak height), Rsm (the mean spacing of irregularities), Rsk (skewness of the profile) and RPc (peak density). The highest strength of the Ni-Cr alloy surface bonding with dental ceramics under operating conditions is provided by abrasive blasting under 600 kPa pressure with 110 µm Al2O3 particles (p < 0.05). Both the abrasive blasting pressure and the particle size of the Al2O3 abrasive significantly affect the joint’s strength (p < 0.05). The most optimal blasting parameters are 600 kPa pressure with 110 µm Al2O3 particles (p < 0.05). They allow the highest bond strength between the Ni-Cr alloy and dental ceramics to be achieved.
Isobaric Thermal Expansivity and Isothermal Compressibility of Liquid Metals
Authors: Starodubtsev Yuri N. , Tsepelev Vladimir S.
Published: May 2023

The relationship between the volumetric thermodynamic coefficients of liquid metals at the melting point and interatomic bond energy was studied. Using dimensional analysis, we obtained equations that connect cohesive energy with thermodynamic coefficients. The relationships were confirmed by experimental data for alkali, alkaline earth, rare earth, and transition metals. Cohesive energy is proportional to the square root of the ratio of melting point Tm divided by thermal expansivity αp. Thermal expansivity does not depend on the atomic size and atomic vibration amplitude. Bulk compressibility βT and internal pressure pi are related to the atomic vibration amplitude by an exponential dependence. Thermal pressure pth decreases with an increasing atomic size. Fcc and hcp metals with high packing density, as well as alkali metals, have the relationships with the highest coefficient of determination. The contribution of electrons and atomic vibrations to the Grüneisen parameter can be calculated for liquid metals at their melting point.
Recent Advances in Magnetic Polymer Composites for BioMEMS: A Review
Authors: Liao Zhengwei , Zoumhani Oualid , Boutry Clementine M.
Published: May 2023

The objective of this review is to investigate the potential of functionalized magnetic polymer composites for use in electromagnetic micro-electro-mechanical systems (MEMS) for biomedical applications. The properties that make magnetic polymer composites particularly interesting for application in the biomedical field are their biocompatibility, their adjustable mechanical, chemical, and magnetic properties, as well as their manufacturing versatility, e.g., by 3D printing or by integration in cleanroom microfabrication processes, which makes them accessible for large-scale production to reach the general public. The review first examines recent advancements in magnetic polymer composites that possess unique features such as self-healing capabilities, shape-memory, and biodegradability. This analysis includes an exploration of the materials and fabrication processes involved in the production of these composites, as well as their potential applications. Subsequently, the review focuses on electromagnetic MEMS for biomedical applications (bioMEMS), including microactuators, micropumps, miniaturized drug delivery systems, microvalves, micromixers, and sensors. The analysis encompasses an examination of the materials and manufacturing processes involved and the specific fields of application for each of these biomedical MEMS devices. Finally, the review discusses missed opportunities and possible synergies in the development of next-generation composite materials and bioMEMS sensors and actuators based on magnetic polymer composites.
Solar-Radiation-Dependent Anisotropic Thermal Management Device with Net Zero Energy from 4D Printing Shape Memory Polymer-Based Composites
Authors: Wang Zhuo , Zhang Yao , Niu Yanhui , Chen Xuejian , Song Jianrong
Published: May 2023

Reports have pointed out that nearly 50% of the global total energy demand for buildings is used for daily heating and cooling. Therefore, it is very important to develop various high-performance thermal management techniques with low energy consumption. In this work, we present an intelligent shape memory polymers (SMPs)-based device with programmable anisotropic thermal conductivity fabricated by a 4D printing technique to assist in thermal management with net zero energy. Highly thermal conductive BN nanosheets were textured in a poly (lactic acid) (PLA) matrix by 3D printing, and the printed composites lamina exhibited significant anisotropic thermal conductivity. The direction of heat flow in devices could be switched programmably, accompanying the light-activated deformation controlled by grayscale of composite, which was demonstrated by the “windows” arrays composed of in-plate thermal conductivity facets and SMPs-based hinge joints, achieving the programmable movement of opening and closing under different light conditions. Based on solar radiation-dependent SMPs coupled with the adjustment of heat flow along anisotropic thermal conductivity, the 4D printed device has been proved in concept for potential applications in thermal management in a building envelop for dynamic climate adaptation, taking place automatically based on the environment.