bluuebunny/crossref_metadata_2025 huggingface dataset:
Acute and Subacute Toxicity Evaluation of Erythrocyte Membrane-Coated Boron Nitride Nanoparticles
Authors: He Jinfeng , Zhang Xuanping , Liu Linhong , Wang Yufei , Liu Renyu , Li Min , Gao Fuping
Published: March 2023

Boron nitride nanoparticles have been reported for boron drug delivery. However, its toxicity has not been systematically elucidated. It is necessary to clarify their potential toxicity profile after administration for clinical application. Here, we prepared erythrocyte membrane-coated boron nitride nanoparticles (BN@RBCM). We expect to use them for boron neutron capture therapy (BNCT) in tumors. In this study, we evaluated the acute toxicity and subacute toxicity of BN@RBCM of about 100 nm and determined the half-lethal dose (LD50) of the particles for mice. The results showed that the LD50 of BN@RBCM was 258.94 mg/kg. No remarkable pathological changes by microscopic observation were observed in the treated animals throughout the study period. These results indicate that BN@RBCM has low toxicity and good biocompatibility, which have great potential for biomedical applications.
Antioxidant and Protective Effects of the Polyphenolic Glycoconjugate from Agrimonia eupatoria L. Herb in the Prevention of Inflammation in Human Cells
Authors: Tsirigotis-Maniecka Marta , Zaczyńska Ewa , Czarny Anna , Jadczyk Piotr , Umińska-Wasiluk Barbara , Gancarz Roman , Pawlaczyk-Graja Izabela
Published: March 2023

Herein, structural and biological studies of a complex biopolymer (polyphenolic glycoconjugate) isolated from the flowering parts of Agrimonia eupatoria L. (AE) are presented. Spectroscopic analyses (UV–Vis and 1H NMR) of the aglycone component of AE confirmed that it consists mainly of aromatic and aliphatic structures characteristic of polyphenols. AE showed significant free radical elimination activity, i.e., ABTS+ and DPPH·, and was an effective copper reducing agent in the CUPRAC test, eventually proving that AE is a powerful antioxidant. AE was nontoxic to human lung adenocarcinoma cells (A549) and mouse fibroblasts (L929) and was nongenotoxic to S. typhimurium bacterial strains TA98 and TA100. Moreover, AE did not induce the release of proinflammatory cytokines such as interleukin 6 (IL-6) and tumor necrosis factor (TNF-α) by human pulmonary vein (HPVE-26) endothelial cells or human peripheral blood mononuclear cells (PBMCs). These findings correlated with the low activation of the transcription factor NF-κB in these cells, which plays an important role in the regulation of the expression of genes responsible for inflammatory mediator synthesis. The AE properties described here suggest that it may be useful for protecting cells from the adverse consequences of oxidative stress and could be valuable as a biomaterial for surface functionalization.
Effects of Fiber Loading on Mechanical Properties of Kenaf Nanocellulose Reinforced Nanohybrid Dental Composite Made of Rice Husk Silica
Authors: Sheng Su Bing , Alawi Rabihah , Johari Yanti , Abdul Muttlib Nor Aidaniza , Hussin Mohd Hazwan , Mohamad Dasmawati , Karobari Mohmed Isaqali
Published: March 2023

The innovation of nanocellulose as reinforcement filler in composites has been a topic of interest in the development of new biomaterials. The objective of this study was to investigate the mechanical properties of a nanohybrid dental composite made of rice husk silica and loaded with different percentages of kenaf nanocellulose. Kenaf cellulose nanocrystals (CNC) were isolated and characterized using a transmission electron microscope (TEM) (Libra 120, Carl Zeiss, Germany). The experimental composite was fabricated with fiber loadings of 1 wt%, 2 wt%, 3 wt%, 4 wt%, and 6 wt% silane-treated kenaf CNC, and subjected to a flexural and compressive strength test (n = 7) using an Instron Universal Testing Machine (Shimadzu, Kyoto, Japan), followed by a scanning electron microscopic assessment of the flexural specimen’s fracture surface using a scanning electron microscope (SEM) (FEI Quanta FEG 450, Hillsborough, OR, USA). Commercial composites Filtek Z350XT (3M ESPE, St. Paul, MN, USA), Neofil (Kerr Corporation, Orange, CA, USA) and Ever-X Posterior (GC Corporation, Tokyo, Japan) were used as a comparison. The average diameter of kenaf CNC under TEM was 6 nm. For flexural and compressive strength tests, one-way ANOVA showed a statistically significant difference (p < 0.05) between all groups. Compared to the control group (0 wt%), the incorporation of kenaf CNC (1 wt%) into rice husk silica nanohybrid dental composite showed a slight improvement in mechanical properties and modes of reinforcement, which was reflected in SEM images of the fracture surface. The optimum dental composite reinforcement made of rice husk was 1 wt% kenaf CNC. Excessive fiber loading results in a decline in mechanical properties. CNC derived from natural sources may be a viable alternative as a reinforcement co-filler at low concentrations.
The Effect of Medical Cooperation in the CKD Patients: 10-Year Multicenter Cohort Study
Authors: Onishi Yasuhiro , Uchida Haruhito A. , Maeshima Yohei , Okuyama Yuka , Otaka Nozomu , Ujike Haruyo , Tanaka Keiko , Takeuchi Hidemi , Tsuji Kenji , Kitagawa Masashi , Tanabe Katsuyuki , Morinaga Hiroshi , Kinomura Masaru , Kitamura Shinji , Sugiyama Hitoshi , Ota Kosuke , Maruyama Keisuke , Hiramatsu Makoto , Oshiro Yoshiyuki , Morioka Shigeru , Takiue Keiichi , Omori Kazuyoshi , Fukushima Masaki , Gamou Naoyuki , Hirata Hiroshi , Sato Ryosuke , Makino Hirofumi , Wada Jun
Published: March 2023

Introduction: While chronic kidney disease (CKD) is one of the most important contributors to mortality from non-communicable diseases, the number of nephrologists is limited worldwide. Medical cooperation is a system of cooperation between primary care physicians and nephrological institutions, consisting of nephrologists and multidisciplinary care teams. Although it has been reported that multidisciplinary care teams contribute to the prevention of worsening renal functions and cardiovascular events, there are few studies on the effect of a medical cooperation system. Methods: We aimed to evaluate the effect of medical cooperation on all-cause mortality and renal prognosis in patients with CKD. One hundred and sixty-eight patients who visited the one hundred and sixty-three clinics and seven general hospitals of Okayama city were recruited between December 2009 and September 2016, and one hundred twenty-three patients were classified into a medical cooperation group. The outcome was defined as the incidence of all-cause mortality, or renal composite outcome (end-stage renal disease or 50% eGFR decline). We evaluated the effects on renal composite outcome and pre-ESRD mortality while incorporating the competing risk for the alternate outcome into a Fine–Gray subdistribution hazard model. Results: The medical cooperation group had more patients with glomerulonephritis (35.0% vs. 2.2%) and less nephrosclerosis (35.0% vs. 64.5%) than the primary care group. Throughout the follow-up period of 5.59 ± 2.78 years, 23 participants (13.7%) died, 41 participants (24.4%) reached 50% decline in eGFR, and 37 participants (22.0%) developed end-stage renal disease (ESRD). All-cause mortality was significantly reduced by medical cooperation (sHR 0.297, 95% CI 0.105–0.835, p = 0.021). However, there was a significant association between medical cooperation and CKD progression (sHR 3.069, 95% CI 1.225–7.687, p = 0.017). Conclusion: We evaluated mortality and ESRD using a CKD cohort with a long-term observation period and concluded that medical cooperation might be expected to influence the quality of medical care in the patients with CKD.
A Multi-Institutional Informed Consent Proposal as a Prevention Tool for Combined Oral Contraceptive Intake and Thrombotic Risk
Authors: Vinciguerra Marina , Cascardi Eliano , Lamanna Bruno , Marrone Maricla , Pititto Fortunato , Macorano Enrica , Sciorio Romualdo , Baldini Giorgio Maria , Malvasi Antonio , Ballini Andrea , Cazzato Gerardo , Vimercati Antonella , Kumaran Senthil , Cicinelli Ettore , Scacco Salvatore , Dellino Miriam
Published: March 2023

Combined oral contraceptives (COC), are among the most widely used contraceptive methods in the world today. Despite the different changes in terms of estrogen/progestogen combinations and dosages, the thromboembolic risk for a woman who takes combined oral contraceptives persists to date. Methods: The review of relevant literature and international guidelines on prescription of combined oral contraceptives made it possible to create a proposal for informed consent to be used for prescribing. Results: The several sections of our consent proposal were designed according to a rationale in order to cover all the aspects presented by worldwide guidelines: how to take, adverse effects, advertisements, extra-contraceptive benefits and effects, a checklist for condition at risk of thromboembolism, the signature of the woman. Conclusions: An informed consent to standardize combined oral contraceptives prescription can improve women’s eligibility, mitigate thromboembolic risk, and assure legal protection to healthcare providers. In this systematic review in particular, we refer to the Italian medical–legal scenario, to which our group of researchers belongs. However, the model proposed was designed in the respect of main healthcare organization guidelines, and it could be easily used by any center in the world.
Coupling Relationship between Rural Settlement Patterns and Landscape Fragmentation in Woodlands and Biological Reserves—A Case of Nanshan National Park
Authors: Li Bo , Ouyang Hao , Wang Tong , Dong Tian
Published: March 2023

Exploring the influence of settlement patterns on the landscape fragmentation in woodlands and biological reserves is key to achieving ecologically sustainable development. In this research, we chose the Nanshan National Park in Hunan Province, China, as a case study, to explore the influence mechanisms. First, we identified the biological reserves through the landscape security patterns of biological conservation. Second, we constructed a coupling coordination model to analyze the coupling relationship between the settlement patterns and landscape fragmentation in the woodlands and biological reserves. The analysis showed that, overall, the effect of the settlement area on the landscape fragmentation in the biological reserves was more pronounced, while the effect of the settlement spread and shape on the landscape fragmentation in the woodlands was more obvious. From a type-specific perspective, we analyzed the coupling relationship between the settlement patterns and (1) the landscape fragmentation in different woodlands and (2) the landscape fragmentation in the biological reserves, namely concerning Leiothrix lutea and Emberiza aureola. We found that the effect of the settlement patterns on the landscape fragmentation of the Leiothrix lutea biological reserve was more significant than that of the landscape fragmentation of its main habitat, the evergreen broad-leaved forest. The effect of settlement patterns on the landscape fragmentation of the Emberiza aureola biological reserve was more significant than that of the landscape fragmentation of its other habitats. In addition, the results demonstrated that the habitat protection of the woodlands was not a substitute for the systematic protection of biosecurity patterns. This research could assist in developing more efficient conservation measures for ecologically protected sites with rural settlements.
Changes in Land Use and Food Security: The Case of the De La Vega Agrarian Shire in the Southern Spanish Province of Granada
Authors: Peña-Rodríguez Francisco-Javier , Entrena-Durán Francisco , Ivorra-Cano Adrià , Llorca-Linde Agustín
Published: March 2023

Changes in land use that are taking place in many parts of the world are having varying effects, depending on the case, on food security in diverse environments. This article analyzes how these changes manifest themselves in the De La Vega territory, an agrarian shire located in the center of the southern Spanish province of Granada. Over recent decades, this shire has been confronted with deep socioeconomic, demographic, and urban transformations that have led and are leading to significant changes in the role of agriculture, land use, and the position of farmers. The results reveal that, over the last four decades, the population has increased (44%), the agricultural area has decreased (40%) as has the usable agricultural land (25%), olive groves have grown exponentially (144%), farms have decreased (68%), and levels of livestock have grown and become more concentrated. Finally, the actions and demands raised by the main actors and social organizations involved in the defense of farming in this shire are examined. These demands and actions have ocurred especially in the peri-urban areas close to what is known as the Granada urban agglomeration, precisely where the changes have been most intense, according to the data analyzed.
Variations of Ecosystem Services Supply and Demand on the Southeast Hilly Area of China: Implications for Ecosystem Protection and Restoration Management
Authors: Zhang Xiao , Wang Jun , Zhao Mingyue , Gao Yan , Liu Yanxu
Published: March 2023

The balance between the supply and demand of ecosystem services (ESs) is an important prerequisite for maintaining the sustainability of ecological protection and restoration project implementation. However, research related to ecological protection and restoration is insufficient for the study of the demand for ecosystem services. Many ecological protection and restoration projects have been implemented in the Fujian Province, but the ESs and the relationship changes between supply and demand are not clear. In this study, multisource remote sensing and public data and the InVEST model were used to quantitatively assess and map four typical ESs, including food production, water yield, soil retention and carbon sequestration. Hotspot analysis was used to analyze the spatial cluster of the ESs supply–demand ratio. The results showed that: (1) there were trade-offs between supporting and regulating services, particularly between carbon sequestration and water yield services, and the strength of trade-offs or synergies between food production and other services was stronger in protection and restoration areas than in other areas; (2) the supply of ESs in the Fujian Province exceeded the demand, and the supply–demand ratio for ESs decreased from the mountainous regions in the northwest interior to the economically developed regions in the southeast coast; and (3) ecological restoration projects improved the relationship between supply and demand for some ESs, while other areas (except protection and restoration areas) had many low-value clusters of supply–demand ratios, especially regarding water yield and carbon sequestration services. Based on the results, our findings also provide suggestions for ensuring the sustainability of ecological protection and restoration in southeast hilly areas and other similar regions.
Anti-Inflammatory Properties of Plants from Serbian Traditional Medicine
Authors: Radovanović Katarina , Gavarić Neda , Aćimović Milica
Published: March 2023

Inflammation is a natural protective response of the human body to a variety of hostile agents and noxious stimuli. Standard anti-inflammatory therapy includes drugs whose usage is associated with a number of side effects. Since ancient times, natural compounds have been used for the treatment of inflammation. Traditionally, the use of medicinal plants is considered safe, inexpensive, and widely acceptable. In Serbia, traditional medicine, based on the strong belief in the power of medicinal herbs, is the widespread form of treatment. This is supported by the fact that Serbia is classified as one of 158 world centers of biodiversity, which confirms that this country is a treasure of medicinal herbs. Some of the most used herbs for the treatment of inflammations of various causes in Serbian tradition are yarrow, common agrimony, couch grass, onion, garlic, marshmallow, common birch, calendula, liquorice, walnut, St. John’s wort, chamomile, peppermint, white willow, sage, and many others. The biological activity and anti-inflammatory effect of selected plants are attributed to different groups of secondary biomolecules such as flavonoids, phenolic acids, sterols, terpenoids, sesquiterpenes, and tannins. This paper provides an overview of plants with traditional anti-inflammatory use in Serbia with reference to available studies that examined this effect. Plants used in traditional medicine could be a powerful source for the development of new remedies. Therefore intensive research on the bioactive potential of medicinal plants in each region should be the focus of scientists around the world.
Sodium Nitroprusside Improves the Growth and Behavior of the Stomata of Silybum marianum L. Subjected to Different Degrees of Drought
Authors: Zangani Esmaeil , Angourani Hossein Rabbi , Andalibi Babak , Rad Saeid Vaezi , Mastinu Andrea
Published: March 2023

The use of growth-stimulating signals to increase the tolerance of plants to water deficits can be an important strategy in the production of plants in dry areas. Therefore, a split-plot experiment with three replications was conducted to evaluate the effects of sodium nitroprusside (SNP) application rate as an NO donor (0, 100, and 200 µM) on the growth and yield parameters of Silybum marianum L. (S. marianum) under different irrigation cut-off times (control, irrigation cut-off from stem elongation, and anthesis). The results of this study showed that with increasing drought severity, leaf RWC, proline content and capitula per plant, 1000 grain weight, plant height, branch per plant, capitula diameter, and the biological and grain yield of S. marianum decreased significantly, whereas the number of grains per capitula increased compared with the control. Also, by irrigation cut-off from the stem elongation stage, the density of leaf stomata at the bottom and top epidermis increased by 64% and 39%, respectively, and the length of the stomata at the bottom epidermis of the leaf decreased up to 28%. In contrast, the results of this experiment showed that the exogenous application of nitric oxide reduced the negative effects of irrigation cut-off, such that the application of 100 µM SNP enhanced RWC content (up to 9%), proline concentration (up to 40%), and grain (up to 34%) and biological (up to 44%) yields in plants under drought stress compared with non-application of SNP. The decrease in the number of capitula per plant and capitula diameter was also compensated by foliar application of 100 µM SNP under stress conditions. In addition, exogenous NO changed the behavior of the stomata during the period of dehydration, such that plants treated with SNP showed a decrease in the stomatal density of the leaf and an increase in the length of the stomata at the leaf bottom epidermis. These results indicate that SNP treatment, especially at 100 µM, was helpful in alleviating the deleterious effects of water deficiency and enhancing the tolerance of S. marianum to withholding irrigation times.
The Role of Renewable Resources for Ecology and Human Health
Authors: Mileva Milka
Published: March 2023

Scientists are increasingly asking very serious and topical questions: what do we throw away as waste from industrial production [...]
Predicting the Efficacy of SBRT for Lung Cancer with 18F-FDG PET/CT Radiogenomics
Authors: Chen Kuifei , Hou Liqiao , Chen Meng , Li Shuling , Shi Yangyang , Raynor William Y. , Yang Haihua
Published: March 2023

Purpose: to develop a radiogenomic model on the basis of 18F-FDG PET/CT radiomics and clinical-parameter EGFR for predicting PFS stratification in lung-cancer patients after SBRT treatment. Methods: A total of 123 patients with lung cancer who had undergone 18F-FDG PET/CT examination before SBRT from September 2014 to December 2021 were retrospectively analyzed. All patients’ PET/CT images were manually segmented, and the radiomic features were extracted. LASSO regression was used to select radiomic features. Logistic regression analysis was used to screen clinical features to establish the clinical EGFR model, and a radiogenomic model was constructed by combining radiomics and clinical EGFR. We used the receiver operating characteristic curve and calibration curve to assess the efficacy of the models. The decision curve and influence curve analysis were used to evaluate the clinical value of the models. The bootstrap method was used to validate the radiogenomic model, and the mean AUC was calculated to assess the model. Results: A total of 2042 radiomics features were extracted. Five radiomic features were related to the PFS stratification of lung-cancer patients with SBRT. T-stage and overall stages (TNM) were independent factors for predicting PFS stratification. AUCs under the ROC curve of the radiomics, clinical EGFR, and radiogenomic models were 0.84, 0.67, and 0.86, respectively. The calibration curve shows that the predicted value of the radiogenomic model was in good agreement with the actual value. The decision and influence curve showed that the model had high clinical application values. After Bootstrap validation, the mean AUC of the radiogenomic model was 0.850(95%CI 0.849–0.851). Conclusions: The radiogenomic model based on 18F-FDG PET/CT radiomics and clinical EGFR has good application value in predicting the PFS stratification of lung-cancer patients after SBRT treatment.
Outcomes in Patients Admitted for Upper Gastrointestinal Bleeding and COVID-19 Infection: A Study of Two Years of the Pandemic
Authors: Cazacu Sergiu , Burtea Daniela , Iovănescu Vlad , Florescu Dan , Iordache Sevastița , Turcu-Stiolica Adina , Sacerdotianu Victor , Ungureanu Bogdan
Published: March 2023

Upper gastrointestinal bleeding (UGIB) represents a major emergency, and patient management requires endoscopic assessment to ensure appropriate treatment. The impact of COVID-19 on patient mortality in UGIB may be related to the combination of respiratory failure and severe bleeding and indirectly to delayed admissions or a reduction in endoscopic procedures. Methods: We conducted a retrospective study involving patients admitted between March 2020 and December 2021 with UGIB and confirmed. Our objective was to compare these types of patients with those negative for SARS-CoV-2 infection, as well as with a pre-pandemic group of patients admitted between May 2018 and December 2019. Results: Thirty-nine patients (4.7%) with UGIB had an active COVID-19 infection. A higher mortality rate (58.97%) and a high risk of death (OR 9.04, p < 0.0001) were noted in the COVID-19 pandemic, mostly because of respiratory failure; endoscopy was not performed in half of the cases. Admissions for UGIB have decreased by 23.7% during the pandemic. Conclusions: COVID-19 infection in patients admitted for UGIB was associated with a higher mortality rate because of respiratory failure and possible delays in or contraindications of treatment.
Effect of Cement Type and Water-to-Cement Ratio on Fresh Properties of Superabsorbent Polymer-Modified Cement Paste
Authors: Dilbas Hasan
Published: March 2023

Superabsorbent polymer (SAP) is a material with the ability to absorb liquid and desorb liquid from and to the environment, and it can ensure the internal curing of cementitious composites. Although the fresh state properties of SAP-modified mixtures (SAPCP) are affected and have been investigated nowadays, the rheological properties of SAPCP are still a virgin field and they are worth studying. Hence, the current study was aimed and conducted to observe what occurred if cements with different chemical compositions, various ratios of water/cement (w/c) and SAP were used together. Accordingly, CEM I 42.5R, CEM II/A-LL 42.5R and CEM IV/B (P) 32.5R were selected as binders in the mixtures, and w/c ratios were 0.40 and 0.50 for SAPCPs. In total, 24 mixtures were designed, produced and tested in the laboratory and spreading table tests, Vicate tests, viscosity tests and shear tests were conducted on the fresh state of the mixtures to observe the fresh behavior of SAPCPs. As a result, it was determined that the SAP, cement and w/c combinations considered in the article were effective on SAPCP fresh properties and rheology. However, it was determined that the use of high amounts of SAP in the mixture, high cement fineness and high oxide ratios in the cement (ratios of silicon dioxide/calcium oxide and aluminum oxide/calcium oxide) negatively affected not only the fresh state properties, but also the rheology. Moreover, the coexistence of the aforementioned negative conditions was the most unfavorable situation: high SAP ratio + high cement fineness + high oxide ratio in SAPCP. For these reasons, it was concluded that cement fineness and chemical composition should be taken into account in the rheology/workability-based design of SAPCPs. Then, the SAP content can be regulated for design purposes.
The Impact of Laser Beam Power on the Microstructure and Some Mechanical Properties of Laser-Alloyed Inconel®600 with WC Particles
Authors: Dziarski Piotr , Makuch Natalia , Kulka Michał
Published: March 2023

Laser surface alloying with WC particles was used in order to improve the wear resistance of Inconel®600-alloy. The applied processing parameters ensured appropriate conditions for the production of composite layers enriched with WC particles that did not melt during the process. As a consequence, the produced layers contained globular shaped WC particles that were well bonded in the matrix. The WC particles were characterized by high hardness HIT = 31.25 GPa and a high Young’s modulus EIT = 609.33 GPa determined by nanoindentation. The most important parameter influencing the thickness of the layer, the percentage of WC particles in the layer and the wear resistance of the produced layers was the power of the laser beam. Three values of laser beam power were used: 1.3 kW, 1.56 kW, and 1.82 kW. An increase in the laser beam power resulted in an increased thickness of the layer from 435 µm to 685 µm. Simultaneously, when the power of the laser beam was higher, the depth of re-melting of the substrate material increased. This was the reason for a decrease in the percentage of WC particles in the composite layer. The layer produced by laser beam power of 1.3 kW contained 20.59% of WC particles, whereas the highest power of the laser beam (1.82 kW) ensured a percentage of WC particles of about 9.46%. As a result, the increase in the laser beam power was the reason for the reduction in the wear resistance of the composite layer. The lowest mass wear intensity factor (Imw = 6.4 mg·cm−2·h−1) characterized the layer produced at laser beam power of 1.3 kW, and the highest Imw (18.5 mg·cm−2·h−1) was obtained for the layer produced with a laser beam power of 1.82 kW. However, all the produced composite layers contained WC particles, which ensured improved wear resistance when compared to the Inconel®600-alloy without the layer (Imw = 60.9 mg·cm−2·h−1).
Study on Microstructure and Mechanical Properties at Constant Electromigration Temperature of Sn2.5Ag0.7Cu0.1RE0.05Ni-GNSs/Cu Solder Joints
Authors: Zhang Chao , Zhang Keke , Gao Yijie , Wang Yuming
Published: March 2023

To solve the electromigration problem of micro−electronic connection solder joints, an ideal electromigration tester was designed, and the thickness of the intermetallic compounds (IMCs), average void diameter, grain orientation, failure, shear strength, and fracture path of Sn2.5Ag0.7Cu0.1RE0.05Ni−GNSs/Cu solder joints under constant−temperature electromigration were studied. The results indicate that the solder joints show evidence of typical electromigration polarity in the asymmetric growth of interfacial IMCs on the anode and cathode sides under the conditions of a current density ≥7 × 103 A/cm2 and an included angle between the c−axis of the β−Sn grains and the current direction θ ≤ 53.2°. The anode−side interfacial IMC is dominated by a Cu6Sn5 phase with a gradually increasing thickness, forming a Cu3Sn phase and showing evidence of microcracks. The Cu6Sn5 phase of the cathode−side interfacial IMC is gradually completely dissolved, and the growth of the Cu3Sn phase is accompanied by the formation of Kirkendall voids. The anisotropic diffusion of Cu atoms in the β−Sn of the micro−solder joints causes increased solder joint resistance and reduced shear strength. The shear fracture path of the solder joints moves from the cathode side near the IMC solder seam to the Cu3Sn interface. The shear fracture mechanism changes from ductile transgranular fracture dominated by β−Sn dimples to brittle fracture dominated by interfacial IMC cleavage and slip steps.
Investigations for Material Tracing in Selective Laser Sintering: Part ΙΙ: Validation of Modified Polymers as Marking Agents
Authors: Eggers Tom , von Lacroix Frank , Goede Martin Friedrich , Persch Christoph , Berlin Werner , Dröder Klaus
Published: March 2023

Selective laser sintering (SLS) is currently in transition to the production of functional components. However, the ability to apply it is confronted with new requirements for reliability and reproducibility. Therefore, an in-depth understanding of aging processes in polymers is essential. Regarding material traceability as well as defective component identification with subsequent cause tracing, the application of a material-inherent marking technology represents a solution. SLS in combination with modified polymers as a marking technology proves to be an efficient opportunity to produce reproducible and high-quality components due to an increased understanding of the process. Based on a selection of modified polymers for use in SLS, which were characterized in part I of the study, this work focuses on the experimental validation of the result. The influence of modified polymers on materials and component properties and the SLS process’s influence on the traceability of modified polymers are examined. Intrinsic and extrinsic material properties as well as mechanical properties, surface quality and sinter density are analyzed. No discernible influences of the modified polymers on the investigated properties could be observed and the traceability of the modified polymers could also be confirmed in the aged powder and component using mass spectroscopy.
Study on Hardness of Heat-Treated CoCrMo Alloy Recycled by Electron Beam Melting
Authors: Vutova Katia , Stefanova Vladislava , Markov Martin , Vassileva Vania
Published: March 2023

The hardness of heat (thermally) treated CoCrMo ingots, recycled by electron beam melting and refining (EBMR) of a technogenic CoCrMo material (waste from the dental technology) under different process conditions (temperature and residence time) is examined. The heat treatment consists of two-step heating up to temperatures of 423 K and 1343 K and retention times of 40 and 60 min, respectively. The influence of various loads (0.98 N, 1.96 N, 2.94 N, 4.9 N, and 9.8 N) on the hardness of the CoCrMo alloy, recycled by EBMR, before and after heat treatment is studied. It has been found that regardless of the EBMR process conditions, the obtained samples after heat treatment have similar hardness values (between 494.2 HV and 505.9 HV) and they are significantly lower than the hardness of the specimens before the heat treatment. The highest hardness (600 HV) is measured in the alloy recycled at 1845 K refining temperature for 20 min. This is due to the smaller crystal structure of the resulting alloy and the higher cobalt content. The results obtained show that the heat treatment leads to considerable changes in the microstructure of the CoCrMo ingots recycled by EBMR. With the increase of the e-beam refining temperature, after the heat treatment, the grains’ size increases and the grains’ shape indicates an incomplete phase transition from γ-fcc to ε-hcp phase. This leads to a slight increase in the hardness of the alloy.
Complex Interdependency of Microstructure, Mechanical Properties, Fatigue Resistance, and Residual Stress of Austenitic Stainless Steels AISI 304L
Authors: Jovičević-Klug Patricia , Jovičević-Klug Matic , Rohwerder Michael , Godec Matjaž , Podgornik Bojan
Published: March 2023

Stainless steels are important in various industries due to their unique properties and durable life cycle. However, with increasing demands for prolonged life cycles, better mechanical properties, and improved residual stresses, new treatment techniques, such as deep cryogenic treatment (DCT), are on the rise to further push the improvement in stainless steels. This study focuses on the effect of DCT on austenitic stainless steel AISI 304L, while also considering the influence of solution annealing temperature on DCT effectiveness. Both aspects are assessed through the research of microstructure, selected mechanical properties (hardness, fracture and impact toughness, compressive and tensile strength, strain-hardening exponent, and fatigue resistance), and residual stresses by comparing the DCT state with conventionally treated counterparts. The results indicate the complex interdependency of investigated microstructural characteristics and residual stress states, which is the main reason for induced changes in mechanical properties. The results show both the significant and insignificant effects of DCT on individual properties of AISI 304L. Overall, solution annealing at a higher temperature (1080 °C) showed more prominent results in combination with DCT, which can be utilized for different manufacturing procedures of austenitic stainless steels for various applications.
Experimental Investigation on Seismic Performance of Non-Uniformly Corroded RC Moment-Resisting Frames
Authors: Chen Shang , Jiang Huanjun
Published: March 2023

To investigate the effect of non-uniform corrosion on the seismic performance of reinforced concrete (RC) frame structures, seven RC frame specimens, including one uncorroded and six corroded frames, were tested under quasi-static loading. The damage modes, force–displacement hysteresis curves and skeleton curves, stiffness degradation, ductility and the energy dissipation capacity of specimens were studied. The influences of the corrosion degree, non-uniform corrosion characteristic value, and axial compression ratio on the seismic performance of the specimens were analyzed. The test results show that non-uniform corrosion of longitudinal bars has a significant effect on the development of seismic damage in RC frames. In comparison with non-corroded RC frames, the loading carrying capacity of corroded frames with non-uniform corrosion characteristics values of 0.18, 0.59, and 0.72 decreased by 8.5%, 14.8%, and 22.3%, the displacement ductility ratios decreased by 6.7%, 8.7%, and 10.0%, and the total cumulative energy dissipation at ultimate displacement values decreased by 24%, 41%, and 54%. For corroded frames with low axial compressive ratios, the loading carrying capacity and energy dissipation capacity rose with the increase in the axial compression ratio.
Influence of Different Metal Types on the Bonding Strength of Concrete Using the Arc Thermal Metal Spraying Method
Authors: Park Jin-Ho , Kim Sang-Youl , Lee Han-Seung , Wi Kwangwoo
Published: March 2023

Exterior finishes protect reinforced concrete buildings against environmental factors, improve their durability, and enhance their exterior design. In this study, the influence of different metal types used in arc thermal metal spraying on the adhesion between concrete and metal coatings was analyzed. Five metals with different melting points were tested, and the differences between their melting points and surface temperatures immediately after thermal spraying were measured. The bonding strength of each metal was evaluated. Additionally, the interface between the concrete surface and metal coating was analyzed using image analysis and optical microscopy. The results demonstrated that Zn achieved the highest bonding strength (1.84 MPa), which had the lowest melting point and surface temperature immediately after spraying, while Cu/Sn achieved the lowest strength (1.38 MPa), which had the highest temperatures. The bonding strength had a closer relationship (R2 = 0.9946) with the difference between the melting point and surface temperature immediately after spraying than that (R2 = 0.9589) with the surface temperature immediately after spraying. The bonding strength increased as the ratio of the non-interfacial failure area to the total area increased, ensuring a stronger attachment to the concrete surface. Overall, the results showed that the bonding strength was significantly affected by the metal type.
Boundary Scenario Generation for HAVs Based on Classification and Local Sampling
Authors: Cai Jinkang , Deng Weiwen , Wang Ying , Guang Haoran , Li Jiangkun , Ding Juan
Published: March 2023

High-level Automated Vehicles (HAVs) are expected to improve traffic safety significantly. However, verifying and evaluating HAVs remains an open problem. Scenario-based testing is a promising method for HAV testing. Boundary scenarios exist around the performance boundary between critical and non-critical scenarios. Testing HAVs in these boundary scenarios is crucial to investigate why collisions cannot be avoided due to small changes in scenario parameters. This study proposes a methodology to generate diverse boundary scenarios to test HAVs. First, an approach is proposed to obtain at least one High-Performance Classifier (HPC) based on two classification algorithms that iteratively guide each other to find uncertain scenarios to improve their performance. Then, the HPC is exploited to find candidate scenarios highly likely to be boundary scenarios. To increase the efficiency of candidate scenario generation, a strategy based on local sampling is presented to find more diverse candidate scenarios based on a small number of them. Numerical experiments show that the HPCs acquired by the method proposed in this study can achieve a classification accuracy of 98% and 99% for random car-following and cut-in scenarios, respectively. Moreover, more than 86% of 271,744 candidate cut-in scenarios derived by local sampling are near the performance boundary.
Stability Estimates for an Arithmetic Functional Equation with Brzdȩk Fixed Point Approaches
Authors: Koh Heejeong
Published: March 2023

We introduce an arithmetic functional equation f(x2+y2)=f(x2)+f(y2) and then investigate stability estimates of the functional equation by using the Brzdȩk fixed point theorem on a non-Archimedean fuzzy metric space and a non-Archimedean fuzzy normed space. To apply the Brzdȩk fixed point theorem, the proof uses the linear relationship between two variables, x and y.
Acute Myocardial Infarction, Subclavian Vein Thrombosis, and Pulmonary Embolism Secondary to COVID-19—A Case Report
Authors: Ivanova Nevena Georgieva
Published: March 2023

Introduction: Coronavirus disease 2019 (COVID-19) is an infectious disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The majority of infected patients develop the clinical picture of a respiratory disease, although some may develop various complications, such as arterial or venous thrombosis. The clinical case presented herein is a rare example of sequential development and combination of acute myocardial infarction, subclavian vein thrombosis (Paget Schroetter syndrome), and pulmonary embolism in the same patient after COVID-19. Case presentation: A 57-year-old man with a 10-day history of a SARS-CoV-2 infection was hospitalized with a clinical, electrocardiographic, and laboratory constellation of an acute inferior-lateral myocardial infarction. He was treated invasively and had one stent implanted. Three days after implantation, the patient developed shortness of breath and palpitation on the background of a swollen and painful right hand. The signs of acute right-sided heart strain observed on the electrocardiogram and the elevated D-dimer levels strongly suggested pulmonary embolism. A Doppler ultrasound and invasive evaluation demonstrated thrombosis of the right subclavian vein. The patient was administered pharmacomechanical and systemic thrombolysis and heparin infusion. Revascularization was achieved 24 h later via successful balloon dilatation of the occluded vessel. Conclusion: Thrombotic complications of COVID-19 can develop in a significant proportion of patients. Concomitant manifestation of these complications in the same patient is extremely rare, presenting at the same time, quite a therapeutic challenge to clinicians due to the need for invasive techniques and simultaneous administration of dual antiaggregant therapy combined with an anticoagulant treatment. Such a combined treatment increases the hemorrhagic risk and requires a serious accumulation of data for the purpose of a long-term antithrombotic prophylaxis in patients with such pathology.
Plasma Enhanced High-Rate Deposition of Advanced Film Materials by Metal Reactive Evaporation in Organosilicon Vapors
Authors: Menshakov Andrey , Bruhanova Yulia , Skorynina Polina , Medvedev Anatoliy
Published: March 2023

Dense homogeneous nanocomposite TiSiCN coatings with a thickness of up to 15 microns and a hardness of up to 42 GPa were obtained by the method of reactive titanium evaporation in a hollow cathode arc discharge in an Ar + C2H2 + N2-gas mixture with the addition of hexamethyldisilazane (HMDS). An analysis of the plasma composition showed that this method allowed for a wide range of changes in the activation degree of all components of the gas mixture, providing a high (up to 20 mA/cm2) ion current density. It is possible to widely change the chemical composition, microstructure, deposition rate, and properties of coatings obtained by this method, by changing the pressure, composition, and activation degree of the vapor–gas mixture. An increase in the fluxes of C2H2, N2, HMDS, and discharge current leads to an increase in the rate of coating formation. However, the optimal coatings from the point of view of microhardness were obtained at a low discharge current of 10 A and relatively low contents of C2H2 (1 sccm) and HMDS (0.3 g/h), exceeding which leads to a decrease in the hardness of the films and the deterioration of their quality, which can be explained by the excessive ionic exposure and the non-optimal chemical composition of the coatings.
Efficient, Breathable, and Compostable Multilayer Air Filter Material Prepared from Plant-Derived Biopolymers
Authors: Wu Rong , Shanbhag Sneha , Selvaganapathy P. Ravi
Published: March 2023

State-of-art face masks and respirators are fabricated as single-use devices using microfibrous polypropylene fabrics, which are challenging to be collected and recycled at a community scale. Compostable face masks and respirators can offer a viable alternative to reducing their environmental impact. In this work, we have developed a compostable air filter produced by electrospinning a plant-derived protein, zein, on a craft paper-based substrate. The electrospun material is tailored to be humidity tolerant and mechanically durable by crosslinking zein with citric acid. The electrospun material demonstrated a high particle filtration efficiency (PFE) of 91.15% and a high pressure drop (PD) of 191.2 Pa using an aerosol particle diameter of 75 ± 2 nm at a face velocity of 10 cm/s. We deployed a pleated structure to reduce the PD or improve the breathability of the electrospun material without compromising the PFE over short- and long-duration tests. Over a 1 h salt loading test, the PD of a single-layer pleated filter increased from 28.9 to 39.1 Pa, while that of the flat sample increased from 169.3 to 327 Pa. The stacking of pleated layers enhanced the PFE while retaining a low PD; a two-layer stack with a pleat width of 5 mm offers a PFE of 95.4 ± 0.34% and a low PD of 75.2 ± 6.1 Pa.
Research on Tunnel-Boring Machine Main Bearing Fatigue Damage and Vibration Response
Authors: Zhang Hongliang , Qu Chuanyong
Published: March 2023

Based on the damage evolution equation of bearing steel, a user subroutine was developed to simulate the fatigue damage behavior of the TBM main bearing under the condition of low speed and heavy load. In addition, the damage evolution law of the main bearing in the time domain and the space domain was studied. Then, a nonlinear spring element was introduced to simulate the interaction between the roller raceway, and the vibration response of the TBM after the main bearing damage was studied using the transient dynamic method. The research shows that the damage risk of the raceway is greater than that of the roller, and the damage risk of the main pushing raceway is greater than that of the other two raceways. The damage of the main bearing will not only lead to the increase in the peak vibration response of the TBM but also cause more frequency components of the response. By monitoring the time domain index of vibration signal, the damage degree to the main bearing can be mastered in real time, providing a reference for the maintenance of the main bearing.
Synthesis and Characterisation of CeO2 Coatings on the AZ31 Alloy for Corrosion Protection and In Vitro Biocompatibility of MC3T3-E1 Pre-Osteoblasts
Authors: Benito-Santiago Sandra E. , Onofre-Bustamante Edgar , Lozano-Puerto Rosa M.
Published: March 2023

The use of bioabsorbable metals as temporary medical implants has attracted considerable research interest as they do not require a second surgical operation for removal after the healing process is completed. However, magnesium (Mg) and its alloys have a degradation rate that is too high in biological environments. Therefore, it must be controlled using various strategies. In this study, an AZ31-Mg-based alloy coated with CeO2 is investigated to analyse the effect of the coating on its corrosion protection and biocompatibility. The AZ31 alloy is anodised with NaOH solution, before coating to stabilise the alloy surface. The CeO2 coating is deposited on anodised AZ31 by chemical conversion treatment. The electrochemical properties of samples are evaluated using electrochemical impedance spectroscopy and cyclic polarisation curves using Hank’s solution. Structural and morphological characterisation of the samples are performed using X-ray diffraction and scanning electron microscopy–energy dispersive X-ray spectroscopy. Additionally, biocompatibility is determined by live/dead assay using MC3T3-E1 pre-osteoblasts. The preliminary results indicate that CeO2 coatings exhibit higher electrochemical properties. Additionally, an increase in the ratio of live/dead cells of the AZ31OH-CeO2 surface is detected, in contrast with AZ31, thus indicating improvement in biocompatibility upon CeO2 coating.
Inflammation and Oxidative Stress in Frailty and Metabolic Syndromes—Two Sides of the Same Coin
Authors: Dzięgielewska-Gęsiak Sylwia , Muc-Wierzgoń Małgorzata
Published: March 2023

In developed countries, aging is often seen as typical, but it is made complicated by many disorders and co-morbidities. Insulin resistance seems to be an underlying pathomechanism in frailty and metabolic syndromes. The decline in insulin sensitivity leads to changes in the oxidant–antioxidant balance and an accelerated inflammatory response, especially by adipocytes and macrophages in adipose tissue, as well as muscle mass density. Thus, in the pathophysiology of syndemic disorders—the metabolic syndrome and frailty syndrome—an extremely important role may be played by increased oxidative stress and pro-inflammatory state. Papers included in this review explored available full texts and the reference lists of relevant studies from the last 20 years, before the end of 2022; we also investigated the PubMed and Google Scholar electronic databases. The online resources describing an elderly population (≥65 years old) published as full texts were searched for the following terms: “oxidative stress and/or inflammation”, “frailty and/or metabolic syndrome”. Then, all resources were analyzed and narratively described in the context of oxidative stress and/or inflammation markers which underlie pathomechanisms of frailty and/or metabolic syndromes in elderly patients. So far, different metabolic pathways discussed in this review show that a similar pathogenesis underlies the development of the metabolic as well as frailty syndromes in the context of increased oxidative stress and acceleration of inflammation. Thus, we argue that the syndemia of the syndromes represents two sides of the same coin.