bluuebunny/crossref_metadata_2025 huggingface dataset:
Anti-Sclerostin Antibodies in Osteoporosis and Other Bone Diseases
Authors: Fabre Stéphanie , Funck-Brentano Thomas , Cohen-Solal Martine
Published: October 2020

The Wnt pathway is a key element of bone remodeling; its activation stimulates bone formation and inhibits bone resorption. The discovery of sclerostin, a natural antagonist of the Wnt pathway, promoted the development of romosozumab, a human monoclonal antibody directed against sclerostin, as well as other anti-sclerostin antibodies. Phase 3 studies have shown the efficacy of romosozumab in the prevention of fractures in postmenopausal women, against placebo but also against alendronate or teriparatide and this treatment also allows bone mineral density (BMD) increase in men. Romosozumab induces the uncoupling of bone remodeling, leading to both an increase in bone formation and a decrease in bone resorption during the first months of treatment. The effect is attenuated over time and reversible when stopped but transition with anti-resorbing agents allows the maintenance or reinforcement of BMD improvements. Some concerns were raised about cardiovascular events. Therefore, romosozumab was recently approved in several countries for the treatment of severe osteoporosis in postmenopausal women with high fracture risk and without a history of heart attack, myocardial infarction or stroke. This review aims to outline the role of sclerostin, the efficacy and safety of anti-sclerostin therapies and in particular romosozumab and their place in therapeutic strategies against osteoporosis or other bone diseases.
The Hidden Factor—Low Quality of Data is a Major Peril in the Identification of Risk Factors for COVID-19 Deaths: A Comment on Nogueira, P.J., et al. “The Role of Health Preconditions on COVID-19 Deaths in Portugal: Evidence from Surveillance Data of the First 20293 Infection Cases”. J. Clin. Med. 2020, 9, 2368
Authors: Costa-Santos Cristina , Ribeiro-Vaz Inês , Monteiro-Soares Matilde
Published: October 2020

We read with great interest the article by Nogueira P [...]
Outcomes after In Utero Myelomeningocele Repair Based on Delivery Location
Authors: Bergh Eric P. , Tsao Kuojen , Austin Mary T. , Fletcher Stephen A. , Lopez Suzanne M. , Moise Kenneth J. , Johnson Anthony , Papanna Ramesha
Published: October 2020

Maternal and pediatric delivery outcomes may vary in patients who underwent open fetal myelomeningocele repair and elected to deliver at the fetal center where their fetal intervention was performed versus at the referring physician’s hospital. A prospective cohort study of 88 patients were evaluated following in utero open fetal myelomeningocele repair at a single fetal center between the years 2011–2019. Exclusion criteria included patients that delivered within two weeks of the procedure (n = 6), or if a patient was lost to follow-up (n = 1). Of 82 patients meeting inclusion criteria, 36 (44%) patients were delivered at the fetal center that performed fetal intervention, and 46 (56%) were delivered locally. Comparative statistics found that with the exception of parity, baseline characteristics and pre-operative variables did not differ between the groups. No differences in oligohydramnios incidence, preterm rupture of membranes, gestational age at delivery or delivery indications were found. Patients who delivered with a referring physician were more likely to be multiparous (p = 0.015). With the exception of a longer neonatal intensive care unit (NICU) stay in the fetal center group (median 30.0 vs. 11.0 days, p = 0.004), there were no differences in neonatal outcomes, including wound dehiscence, cerebrospinal fluid leakage, patch management, ventricular diversion, or prematurity complications. Therefore, we conclude that it is safe to allow patients to travel home for obstetric and neonatal management after open fetal myelomeningocele repair.
The 10-Year Study of the Impact of Particulate Matters on Mortality in Two Transit Cities in North-Eastern Poland (PL-PARTICLES)
Authors: Kuźma Łukasz , Dąbrowski Emil Julian , Kurasz Anna , Bachórzewska-Gajewska Hanna , Dobrzycki Sławomir
Published: October 2020

The detrimental influence of air pollution on mortality has been established in a series of studies. The majority of them were conducted in large, highly polluted cities—there is a lack of studies from small, relatively clean regions. The aim was to analyze the short-term impact of particulate matters (PMs) on mortality in north-eastern Poland. Time-stratified case-crossover design was performed for mortality in years 2008–2017. Daily concentrations of PM2.5 (28.4 µg/m3, interquartile range (IQR) = 25.2) vs. (12.6 µg/m3, IQR = 9.0) and PM10 (29.0 µg/m3, IQR = 18.0) vs. (21.7 µg/m3, IQR = 14.5) were higher in Łomża than Suwałki (p < 0.001). Impact of PM2.5 on mortality was recorded in Łomża (odds ratio (OR) for IQR increase 1.061, 1.017–1.105, p = 0.06, lag 0) and Suwałki (OR for IQR increase 1.044, 1.001–1.089, p = 0.004, lag 0). PM10 had an impact on mortality in Łomża (OR for IQR increase 1.028, 1.000–1.058, p = 0.049, lag 1). Cardiovascular mortality was affected by increase of PM2.5 in Łomża (1.086, 1.020–1.156, p = 0.01) and Suwałki (1.085, 1.005–1.171, p = 0.04). PM2.5 had an influence on respiratory mortality in Łomża (1.163, 1.021–1.380, p = 0.03, lag 1). In the whole studied region, despite differences in the air quality, the influence of PMs on mortality was observed.
Beta-Blocker and Renin–Angiotensin System Inhibitor Combination Therapy in Patients with Acute Myocardial Infarction and Prediabetes or Diabetes Who Underwent Successful Implantation of Newer-Generation Drug-Eluting Stents: A Retrospective Observational Registry Study
Authors: Kim Yong Hoon , Her Ae-Young , Jeong Myung Ho , Kim Byeong-Keuk , Hong Sung-Jin , Kim Seunghwan , Ahn Chul-Min , Kim Jung-Sun , Ko Young-Guk , Choi Donghoon , Hong Myeong-Ki , Jang Yangsoo
Published: October 2020

Long-term clinical outcomes in patients with acute myocardial infarction (AMI) and prediabetes or diabetes who received ß-blockers (BB) and renin–angiotensin system inhibitor (RASI) therapy after successful newer-generation drug-eluting stent (DES) implantation are limited. We compared the two-year clinical outcomes in such patients. A total of 9466 patients with AMI in the Korea AMI Registry were classified into six groups according to their glycemic status and presence or absence of BB + RASI therapy: normoglycemia and BB + RASI users (n = 2217) or nonusers (n = 243), prediabetes and BB + RASI users (n = 2601) or nonusers (n = 306), and diabetes and BB + RASI users (n = 3682) or nonusers (n = 417). The primary endpoint was major adverse cardiac events (MACEs) defined as all-cause death, recurrent myocardial infarction (Re-MI), or any repeat revascularization, and the secondary endpoint was the cumulative incidence of hospitalization for heart failure (HHF). In patients with BB + RASI, despite similar primary and secondary clinical points between the prediabetes and diabetes groups, the cumulative incidence of Re-MI (adjusted hazard ratio: 1.660; 95% confidence interval: 1.000–2.755; p = 0.020) was higher in the diabetes group than in the prediabetes group. In all three different glycemic groups, BB + RASI users showed reduced MACEs, cardiac death, and HHF compared to those of BB + RASI nonusers. In this retrospective observational registry study, BB + RASI therapy showed comparable clinical outcomes except for Re-MI between prediabetes and diabetes in patients with AMI during a two-year follow-up period.
Chest Tube Drainage Versus Conservative Management as the Initial Treatment of Primary Spontaneous Pneumothorax: A Systematic Review and Meta-Analysis
Authors: Lee Jong Hyuk , Kim Ryul , Park Chang Min
Published: October 2020

Objectives: This systematic review and meta-analysis aimed to compare chest tube drainage and conservative management as the initial treatment of primary spontaneous pneumothorax (PSP). Methods: Studies including PSP patients who received tube drainage or conservative management as the initial treatment were searched in OVID-MEDLINE and Embase through 14 February 2020. The primary outcome was the relative risk (RR) of PSP recurrence, and secondary outcomes were RRs of PSP resolution and adverse events during treatment. A random-effect model using the Mantel–Haenszel method was used to pool RRs. Subgroup and meta-regression analyses were performed to investigate significant predictors of PSP recurrence. Results: In total, 11,922 PSP cases from eight studies were analysed, of which 6344 were treated with tube drainage and 5578 were treated with conservative management. The pooled RR of PSP recurrence for conservative management against tube drainage was 0.98 (95% confidence interval [CI], 0.75–1.28; p = 0.894). Subgroup and meta-regression analyses revealed that study design (p = 0.816), allocation of the PSP amount in each management group (p = 0.191), and assessment time for recurrence had no significant impact on PSP recurrence (p = 0.816). There was no publication bias (p = 0.475). The risk of adverse events of conservative management was significantly lower than that of tube drainage (pooled RR, 0.22; 95% CI, 0.08–1.15; p = 0.003). However, no difference was found between the two groups in terms of PSP resolution (pooled RR, 1.01; 95% CI, 0.9–1.15; p = 0.814). Conclusions: As the initial treatment for PSP, conservative management is comparable to chest tube drainage in terms of PSP recurrence and resolution after treatment, with fewer adverse events during treatment.
Coagulation Changes during Central Hypovolemia across Seasons
Authors: Goswami Nandu , Taucher Alexander Andreas , Brix Bianca , Roessler Andreas , Koestenberger Martin , Reibnegger Gilbert , Cvirn Gerhard
Published: October 2020

Lower body negative pressure (LBNP) application simulates hemorrhage. We investigated how seasons affect coagulation values at rest and during LBNP. Healthy participants were tested in cold (November–April) and warm (May–October) months. Following a 30-min supine period, LBNP was started at −10 mmHg and increased by −10 mmHg every five minutes until a maximum of −40 mmHg. Recovery was for 10 min. Blood was collected at baseline, end of LBNP, and end of recovery. Hemostatic profiling included standard coagulation tests, calibrated automated thrombogram, thrombelastometry, impedance aggregometry, and thrombin formation markers. Seven men (25.0 ± 3.6 years, 79.7 ± 7.8 kg weight, 182.4 ± 3.3 cm height, and 23.8 ± 2.3 kg/m2 BMI) and six women (25.0 ± 2.4 years, 61.0 ± 8.4 kg weight, 167 ± 4.7 cm height, and 21.8 ± 2.4 kg/m2 BMI) participated. Baseline levels of prothrombin (FII), tissue factor (TF) and markers for thrombin generation F1+2 and the thrombin/antithrombin complex (TAT) were higher during summer. Factor VIII, prothrombin fragment 1+2 (F1+2), TAT and the coagulation time showed significant increases during LBNP in both seasons. Some calibrated automated thrombography variables (Calibrated automated thrombography (CAT): lag, time to peak (ttPeak), peak) shifted in a procoagulant direction during LBNP in summer. Red blood cell counts (RBC), hemoglobin and white blood cell counts (WBC) decreased during LBNP. LBNP application reduced prothrombin time in winter and activated partial thromboplastin time in summer. Greater levels of FII, TF, F1+2, and TAT—a more pronounced LBNP-induced procoagulative effect, especially in CAT parameters (lag time (LT), Peak, ttPeak, Velindex)—were seen in summer. These results could have substantial medical implications.
Omics in Myopia
Authors: Grochowski Emil Tomasz , Pietrowska Karolina , Kowalczyk Tomasz , Mariak Zofia , Kretowski Adam , Ciborowski Michal , Dmuchowska Diana Anna
Published: October 2020

Myopia is a globally emerging issue, with multiple medical and socio-economic burdens and no well-established causal treatment thus far. A better insight into altered biochemical pathways and underlying pathogenesis might facilitate early diagnosis and treatment of myopia, ultimately leading to the development of more effective preventive and therapeutic measures. In this review, we summarize current data about the metabolomics and proteomics of myopia in humans and present various experimental approaches and animal models, along with their strengths and weaknesses. We also discuss the potential applicability of these findings to medical practice and suggest directions for future research.
New Diagnostic and Therapeutic Approaches for the Care of the Severely Injured Patient
Authors: Hildebrand Frank , Horst Klemens
Published: October 2020

Severe trauma remains a leading cause of death, especially in the younger population [...]
Subjective Happiness and Satisfaction in Postoperative Anisometropic Patients after Refractive Surgery for Myopia
Authors: Negishi Kazuno , Toda Ikuko , Ayaki Masahiko , Torii Hidemasa , Tsubota Kazuo
Published: October 2020

Laser-assisted in situ keratomileusis (LASIK) contributes to increased patient happiness one month after surgery; however, longer term effects are unknown. We performed a retrospective cross-sectional study on 472 patients who underwent bilateral LASIK surgery to measure happiness and satisfaction with LASIK, and to identify affecting factors. Patients completed questionnaires on satisfaction with the surgery and the subjective happiness scale (SHS) before, and 1, 3, 6, and 12 months after surgery. Multiple regression analyses were performed to determine independent predictors of SHS and satisfaction scores. Mean SHS increased at one month but was similar to baseline levels by six months. The SHS of older patients was greater than younger ones at baseline and at one and three months, while satisfaction among the older group was poorer at one and three months. Multiple regression analyses revealed that the decrease in SHS score from one month to three months correlated with baseline SHS, SHS at one month, uncorrected distance visual acuity (UDVA), and age. Regression analysis revealed SHS at six months correlated with preoperative SHS, SHS at one month, and satisfaction at six months. Satisfaction at final visit correlated with age, UDVA, anisometropia, and with SHS at each visit. We conclude that happiness and satisfaction were age- and UDVA-dependent, and anisometropic patients report poorer satisfaction scores.
Chorioretinal Side Effects of Therapeutic Ocular Irradiation: A Multimodal Imaging Approach
Authors: Midena Giulia , Parrozzani Raffaele , Frizziero Luisa , Midena Edoardo
Published: October 2020

Radiation chorioretinopathy, radiation maculopathy, and radiation optic neuropathy are the major complications of ophthalmic radiotherapy. Optical coherence tomography (OCT) and OCT angiography (OCTA) are revolutionary imaging methods, allowing the visualization of the retinal cellular architecture and the retinal vascular system, respectively. In recent years this multimodal imaging approach has been applied to several retinal disease, but its role in the clinical characterization of retinal complications secondary to ophthalmic radiotherapy has not yet been defined. The purpose of this review is to critically evaluate the role of OCT and OCTA in the clinical assessment of radiation-induced chorioretinopathy, maculopathy, and optic neuropathy.
Data Reproducibility and Effectiveness of Bronchodilators for Improving Physical Activity in COPD Patients
Authors: Minakata Yoshiaki , Sasaki Seigo
Published: October 2020

Increasing physical activity (PA) in patients with chronic obstructive pulmonary disease (COPD) is an important issue, however, the effect of bronchodilators on PA is still controversial. The indicators of PA, as measured by an accelerometer, can easily fluctuate based on several factors, which might cause inconsistent results. In this review, we listed the indicators of PA and the factors influencing the reproducibility of indicators of PA, and reviewed reports in which the effects of bronchodilators on PA were evaluated by an accelerometer. Then, we investigated the association between the processing of influencing factors and the effectiveness of bronchodilators for improving the PA of COPD patients. Fifteen reports were extracted using the PubMed database. In all seven reports in which adjustment was performed for at least two of four influencing factors (non-wear time, data from days with special behavior, environmental factors, and number of valid days required to obtain reproducible data), bronchodilators showed beneficial effects on PA. No adjustment was made for any of these factors in any of the four bronchodilator-ineffective reports. This suggests that the processing of influencing factors to secure reproducibility might affect the results regarding the effectiveness of bronchodilators for improving PA in COPD patients.
Development of Monitoring System for Assessing Rheumatoid Arthritis within 5 Minutes Using a Drop of Bio-Fluids
Authors: Koh Jung Hee , Lee Saseong , Kim Hyun-Sook , Lee Kyuheon , Lee Chang Seop , Yoo Seung-Ah , Lee Naeun , Kim Wan-Uk
Published: October 2020

Rheumatoid arthritis (RA) disease activity fluctuates over time. The disease activity score 28 (DAS28ESR) is a widely used and validated scoring system for assessing RA activity; however, it requires time and expertise. This study aimed to develop a new molecular assay capable of rapidly and objectively assessing RA activity. We used a rapid immuno-assay system (FREND™) to measure soluble CD14 (sCD14) levels, which reflect the DAS28ESR. SCD14 concentrations in urine and serum of RA patients were measured, and RA activity and responses to anti-rheumatic drugs were examined at baseline and after 6 months. FREND™ quantified sCD14 levels in a drop of serum and urine accurately and within 5 min. Serum sCD14 concentrations and its changes correlated well with disease activity and treatment responses, and the results were comparable to C-reactive protein. The new composite indices, including the DAS28CD14 and simplified DASCD14, better detected RA activity than a single sCD14 value and correlated strongly with the DAS28ESR. These indices exhibited excellent diagnostic performance for discriminating a good response 6 months after treatment. We developed a new system for assessing RA activity and therapeutic outcome within 5 min. CD14-based composite indices may have utility for accurate and frequent monitoring of RA status.
Dynamic Changes of Inhibitory Killer-Immunoglobulin-Like Receptors on NK Cells after Allogeneic Hematopoietic Stem Cell Transplantation: An Initial Study
Authors: Dekojová Tereza , Houdová Lucie , Fatka Jiří , Pitule Pavel , Ostašov Pavel , Caputo Valentina S. , Gmucová Hana , Lysák Daniel , Jindra Pavel , Holubová Monika
Published: October 2020

Killer-immunoglobulin-like receptors (KIRs) are critical natural killer (NK) cell regulators. The expression of KIRs is a dynamic process influenced by many factors. Their ligands—HLA(Human Leukocyte Antigen) class I molecules—are expressed on all nucleated cells that keep NK cells under control. In hematopoietic stem cell transplantation (HSCT), NK cells play an essential role in relapse protection. In the presented pilot study, we characterized the dynamic expression of inhibitory KIRS (iKIRs), which protect cells against untoward lysis, in donors and patients during the first three months after HSCT using flow cytometry. The expression of all iKIRs was highly variable and sometimes correlated with patients’ clinical presentation and therapy regiment. Cyclophosphamide (Cy) in the graft-versus-host disease (GvHD) prevention protocol downregulated KIR2DL1 to just 25% of the original donor value, and the FEAM (Fludarabine + Etoposid + Ara-C + Melphalan) conditioning protocol reduced KIR2DL3. In lymphoid neoplasms, there was a slightly increased KIR2DL3 expression compared to myeloid malignancies. Additionally, we showed that the ex vivo activation of NK cells did not alter the level of iKIRs. Our study shows the influence of pre- and post-transplantation protocols on iKIR expression on the surface of NK cells and the importance of monitoring their cell surface.
Effects of Heavy Ion Particle Irradiation on Spore Germination of Bacillus spp. from Extremely Hot and Cold Environments
Authors: Zammuto Vincenzo , Rizzo Maria G. , De Plano Laura M. , Franco Domenico , Guglielmino Salvatore , Caccamo Maria T. , Magazù Salvatore , Fujimori Akira , Giudice Angelina Lo , Guglielmin Mauro , McAlpin Kevin Roderick , Moeller Ralf , Gugliandolo Concetta
Published: October 2020

Extremophiles are optimal models in experimentally addressing questions about the effects of cosmic radiation on biological systems. The resistance to high charge energy (HZE) particles, and helium (He) ions and iron (Fe) ions (LET at 2.2 and 200 keV/µm, respectively, until 1000 Gy), of spores from two thermophiles, Bacillushorneckiae SBP3 and Bacilluslicheniformis T14, and two psychrotolerants, Bacillus sp. A34 and A43, was investigated. Spores survived He irradiation better, whereas they were more sensitive to Fe irradiation (until 500 Gy), with spores from thermophiles being more resistant to irradiations than psychrotolerants. The survived spores showed different germination kinetics, depending on the type/dose of irradiation and the germinant used. After exposure to He 1000 Gy, D-glucose increased the lag time of thermophilic spores and induced germination of psychrotolerants, whereas L-alanine and L-valine increased the germination efficiency, except alanine for A43. FTIR spectra showed important modifications to the structural components of spores after Fe irradiation at 250 Gy, which could explain the block in spore germination, whereas minor changes were observed after He radiation that could be related to the increased permeability of the inner membranes and alterations of receptor complex structures. Our results give new insights on HZE resistance of extremophiles that are useful in different contexts, including astrobiology.
Study of the Piston Secondary Movement on the Tribological Performance of a Single Cylinder Low-Displacement Diesel Engine
Authors: Forero Jorge Duarte , Ochoa Guillermo Valencia , Alvarado Wlamyr Palacios
Published: October 2020

The present study aims to analyze the secondary movement of the piston considering the deformations present in the piston skirt, the hydrodynamic lubrication, and the effects of the clearances in the connecting rod bearings. The analysis of the piston movement is performed by developing a mathematical model, which was used to evaluate the dynamic characteristics of the piston movement, the slap force on the piston skirt, the effect of the secondary piston movement on the connecting rod, and the influence of clearances in the connecting rod bearings and in the piston. For the study, the geometric of the crankshaft-connecting rod–piston system of a single-cylinder diesel engine is taken as a reference. The deformation model of the piston was carried out by means of a symmetric finite element model (FEM), which was integrated into the mathematical model of the piston. MATLAB® software (The MathWorks Inc., Natick, MA, USA) is used for the development of model simulations. The obtained results show that during the combustion cycle, there are six changes of direction in the secondary movement of the piston with lateral and angular velocities that can reach a magnitude of 0.13 m/s and 4 rad/s. The lateral and angular movement of the piston during its travel causes the appearance of impacts on the piston skirt with the cylinder liner, which produces an increase of approximately 500 N in the hydrodynamic forces in the connecting rod bearings. The force analysis shows that the range of the maximum magnitudes of these forces is between 1900 N and 3480 N. The increase in clearance between the cylinder liner and the piston skirt (Cpc) causes a greater lateral displacement and an increase in the angle of inclination of the piston. Analysis of the change in connecting rod bearing clearance shows that there are critical values in relation to clearance Cpc. The model presented allows us to analyze the different characteristics of the secondary movement of the piston, which involve the interaction between the piston skirt and the cylinder liner. Additionally, the influence of this movement on the connecting rod bearings is considered. The foregoing can be used as an analysis tool for the study of designs and/or modifications in the engine in such a way that greater durability of the components, reductions in acoustic emissions, and reduction in friction losses are achieved.
Fabrication of All-Solid Organic Electrochromic Devices on Absorptive Paper Substrates Utilizing a Simplified Lateral Architecture
Authors: Liu Guodong , Liu Yu , Zhang Meiyun , Pettersson Fredrik , Toivakka Martti
Published: October 2020

Poly(3,4-ethylenedioxythiophene) doped with the polymer anion poly(styrenesulfonate), PEDOT:PSS, is a common electrochromic material used in the preparation of electrochromic devices (ECDs). In this paper, the PEDOT:PSS doped with a solvent was used both as the electrode and the electrochromic functional layer for fabrication of ECDs on absorptive paper surfaces. The doped PEDOT:PSS dispersion was assessed for the film-forming evenness, sheet resistance and conductivity, and the performance of prepared ECDs for their color contrast and switching dynamics. The ECD performance is discussed in relation to the absorptive characteristics of the substrates. The results indicate that it is feasible to prepare ECDs onto absorptive substrates, despite the partial polymer material imbibition into them. The extent of polymer absorption influences the ECD performance: an increased absorption reduces the color contrast but speeds up the color switching. The electrochemical properties of the used solid electrolyte were found to be crucial for functioning of the ECDs. Insufficient ion transport and associated high resistance led to failure of the devices.
SLM Manufacturing Redesign of Cooling Inserts for High Production Steel Moulds and Benchmarking with Other Industrial Additive Manufacturing Strategies
Authors: Minguella-Canela Joaquim , Morales Planas Sergio , De los Santos-López María Antonia
Published: October 2020

Moulding technologies are remarkably effective for parts requiring high production volumes. Yet cooling the moulds after each injection can cause a significant loss of time. A possibility for reducing the cooling times is to use cooling inserts and conformal cooling strategies. In the present case, the original inserts of a mould must be substituted because the original material cannot be utilized anymore (toxicity). Will it be technically feasible to achieve a proper cooling only by modifying the inserts? Here, the cooling inserts of high production steel moulds utilized to manufacture ribs for swimming pool sinks’ plastic cages are redesigned, simulated and manufactured, taking advantage of Selective Laser Melting possibilities and without modifying the geometry of the obtained parts, nor the rest of the moulds. The results reveal a reduction in the mould cooling times of up to 8%, while maintaining the same conformation properties, thus leading to important savings of time and some global costs in the production outcomes. The study also benchmarks the production economic limits of this approach compared to other possible strategies, such as the development of full new conformal cooling moulds or the industrial production of the parts with plastic additive manufacturing (multi jet fusion) technology.
Extreme Mechanical Properties of Regular Tensegrity Unit Cells in 3D Lattice Metamaterials
Authors: Al Sabouni-Zawadzka Anna
Published: October 2020

The study focuses on the identification of extreme mechanical properties of 3D lattice metamaterials based on regular tensegrity modules: 4-strut simplex, 3-strut simplex, expanded octahedron, truncated tetrahedron and X-module. The basis of the analysis is a continuum model which is used to find the equivalent elasticity matrices of the unit cells. For each examined tensegrity module a line of extreme properties is determined, which indicates the occurrence of the soft mode of deformation. Moreover, the eigenvectors corresponding to soft and stiff deformation modes are calculated and presented graphically. The obtained results are promising from the point of view of future creation of tensegrity lattices and metamaterials with extreme mechanical properties. One of the analysed materials is identified as quasi bimode, two as quasi trimodes, another one as a trimode and one more as a unimode.
An Overview of Serum Albumin Interactions with Biomedical Alloys
Authors: Klok Oksana , Igual Munoz Anna , Mischler Stefano
Published: October 2020

Understanding the interactions between biomedical alloys and body fluids is of importance for the successful and safe performance of implanted devices. Albumin, as the first protein that comes in contact with an implant surface, can determine the biocompatibility of biomedical alloys. The interaction of albumin with biomedical alloys is a complex process influenced by numerous factors. This literature overview aims at presenting the current understanding of the mechanisms of serum albumin (both Bovine Serum Albumin, BSA, and Human Serum Albumin, HSA) interactions with biomedical alloys, considering only those research works that present a mechanistic description of the involved phenomena. Widely used biomedical alloys, such as 316L steel, CoCrMo and Titanium alloys are specifically addressed in this overview. Considering the literature analysis, four albumin-related phenomena can be distinguished: adsorption, reduction, precipitation, and protein-metal binding. The experimental techniques used to understand and quantify those phenomena are described together with the studied parameters influencing them. The crucial effect of the electrochemical potential on those phenomena is highlighted. The effect of the albumin-related phenomena on corrosion behavior of biomedical materials also is discussed.
Tensile Notch Sensitivity of Additively Manufactured IN 625 Superalloy
Authors: Matache Gheorghe , Paraschiv Alexandru , Condruz Mihaela Raluca
Published: October 2020

The notch sensitivity of additively manufactured IN 625 superalloy produces by laser powder bed fusion (LPBF) has been investigated by tensile testing of cylindrical test pieces. Smooth and V-notched test pieces with four different radii were tested both in as-built state and after a stress relief heat treatment for 1 h at 900 °C. Regardless of the notch root radius, the investigated alloy exhibits notch strength ratios higher than unity in both as-built and in stress-relieved states, showing that the additive manufactured IN 625 alloy is not prone to brittleness induced by the presence of V-notches. Higher values of notch strength ratios were recorded for the as-built material as a result of the higher internal stress level induced by the manufacturing process. Due to the higher triaxiality of stresses induced by notches, for both as-built and stress-relieved states, the proof strength of the notched test pieces is even higher than the tensile strength of the smooth test pieces tested in the same conditions. SEM fractographic analysis revealed a mixed mode of ductile and brittle fracture morphology of the V-notched specimens regardless the notch root radius. A more dominant ductile mode of fracture was encountered for stress-relieved test pieces than in the case of the as-built state. However, future research is needed to better understand the influence of notches on additive manufactured IN 625 alloy behaviour under more complex stresses.
The Use of De-Vulcanized Recycled Rubber in the Modification of Road Bitumen
Authors: Gawdzik Barbara , Matynia Tadeusz , Błażejowski Krzysztof
Published: October 2020

Rubber from recycled car tires and styrene-butadiene-styrene (SBS) were used for the chemical modification of commercially available road bitumen 50/70 (EN 12591). The modification process began with the addition of rubber into asphalt and heating the whole amount at the temperature of 190 °C or 220 °C. Under such conditions, de-vulcanization of rubber took place. Next, SBS and sulfur as a cross-linker were added and the heating was continued so that cross-linking of SBS and the de-vulcanized rubber proceeded. In the studies on the influence of rubber concentration on the final properties of asphalt 10% or 15% of rubber was considered. Chemical modification reactions were performed within 2, 4, and 8 h. The results showed that both the modification at 190 °C and 220 °C affected the properties of the base asphalt efficiently, although the asphalt modified at 190 °C contained more non-degraded rubber. Increasing the modification time led to dissolution of the rubber crumbs and its de-vulcanization. Bitumens modified in this way are characterized by high storage stabilities. Their behavior at low temperatures also deserves attention.
Influence of Dispersing Method on the Quality of Nano-Admixtures Homogenization in Cement Matrix
Authors: Horszczaruk Elżbieta , Łukowski Paweł , Seul Cyprian
Published: October 2020

In recent years, a nano-modification of the cement composites allowed to develop a number of new materials. The use of even small amount of nano-admixture makes possible not only to improve the physico-mechanical properties of the cement materials, but also to obtain the composite with high usability, optimised for the given application. The basic problem of nano-modification of the cement composites remains the effectiveness of dispersing the nanomaterials inside the cement matrix. This paper deals with the effect of the type and size of the nanoparticles on the tendency to their agglomeration in the cement matrix. The main techniques and methods of dispersing the nanomaterials are presented. It has been demonstrated, on the basis of the results of testing of three nanomodifiers of 0D type (nano-SiO2, nano-Fe3O4 and nano-Pb3O4), how the structure and properties of the nanomaterial affect the behaviour of the particles when dissolving in the mixing water and applying a superplasticiser. The nanoparticles had similar size of about 100 nm but different physico-chemical properties. The methods of dispersing covered the use of high-speed mechanical stirring and ultrasonication. The influence of the method of nano-modifier dispersing on the mechanical performance of the cement composite has been presented on the basis of the results of testing the cement mortars modified with 3% admixture of nano-SiO2.
Two-Step Laser Post-Processing for the Surface Functionalization of Additively Manufactured Ti-6Al-4V Parts
Authors: Solheid Juliana S. , Wunsch Torsten , Trouillet Vanessa , Weigel Simone , Scharnweber Tim , Seifert Hans Jürgen , Pfleging Wilhelm
Published: October 2020

Laser powder bed fusion (LPBF) is one of the additive manufacturing methods used to build metallic parts. To achieve the design requirements, the LPBF process chain can become long and complex. This work aimed to use different laser techniques as alternatives to traditional post-processes, in order to add value and new perspectives on applications, while also simplifying the process chain. Laser polishing (LP) with a continuous wave laser was used for improving the surface quality of the parts, and an ultrashort pulse laser was applied to functionalize it. Each technique, individually and combined, was performed following distinct stages of the process chain. In addition to removing asperities, the samples after LP had contact angles within the hydrophilic range. In contrast, all functionalized surfaces presented hydrophobicity. Oxides were predominant on these samples, while prior to the second laser processing step, the presence of TiN and TiC was also observed. The cell growth viability study indicated that any post-process applied did not negatively affect the biocompatibility of the parts. The presented approach was considered a suitable post-process option for achieving different functionalities in localized areas of the parts, for replacing certain steps of the process chain, or a combination of both.
Evaluation of Milled Titanium versus Laser Sintered Co-Cr Abutments on the Marginal Misfit in Internal Implant-Abutment Connection
Authors: Gonzalo Esther , Vizoso Beatriz , Lopez-Suarez Carlos , Diaz Pedro , Pelaez Jesus , Suarez Maria J.
Published: October 2020

The precision of fit at the implant-abutment connection is an important criterion for the clinical success of restorations and implants. Several factors are involved among which are the abutment materials and manufacturing techniques. The aim of this study was to investigate the effect of two materials and methods of manufacturing implant abutments, milled titanium versus laser sintered Co-Cr, on the marginal misfit at the implant-abutment interface. Scanning electron microscopes (SEM) were used to geometrically measure the marginal vertical discrepancy of a total of 80 specimens, classified into eight categories, according to the implant system and abutment. The data were statistically analyzed by Student’s paired t test, one-way and two-way ANOVA with the Bonferroni-Holm correction at the significance level of p = 0.05. Milled titanium abutments demonstrated the lowest misfit values in the implant systems analyzed. The marginal fit of all the groups was within the clinically acceptable range for implant prostheses.
On a Beam of Light: Photoprotective Activities of the Marine Carotenoids Astaxanthin and Fucoxanthin in Suppression of Inflammation and Cancer
Authors: Catanzaro Elena , Bishayee Anupam , Fimognari Carmela
Published: October 2020

Every day, we come into contact with ultraviolet radiation (UVR). If under medical supervision, small amounts of UVR could be beneficial, the detrimental and hazardous effects of UVR exposure dictate an unbalance towards the risks on the risk-benefit ratio. Acute and chronic effects of ultraviolet-A and ultraviolet-B involve mainly the skin, the immune system, and the eyes. Photodamage is an umbrella term that includes general phototoxicity, photoaging, and cancer caused by UVR. All these phenomena are mediated by direct or indirect oxidative stress and inflammation and are strictly connected one to the other. Astaxanthin (ASX) and fucoxanthin (FX) are peculiar marine carotenoids characterized by outstanding antioxidant properties. In particular, ASX showed exceptional efficacy in counteracting all categories of photodamages, in vitro and in vivo, thanks to both antioxidant potential and activation of alternative pathways. Less evidence has been produced about FX, but it still represents an interesting promise to prevent the detrimental effect of UVR. Altogether, these results highlight the importance of digging into the marine ecosystem to look for new compounds that could be beneficial for human health and confirm that the marine environment is as much as full of active compounds as the terrestrial one, it just needs to be more explored.
SMP Production in an Anaerobic Submerged Membrane Bioreactor (AnMBR) at Different Organic Loading Rates
Authors: Medina Sandra C. , Zamora-Vacca Nataly , Luna Hector J. , Ratkovich Nicolas , Rodríguez Susa Manuel
Published: October 2020

Anaerobic membrane bioreactors (AnMBRs) have demonstrated an excellent capability to treat domestic wastewater. However, biofouling reduces membrane permeability, increasing operational costs and overall energy demand. Soluble microbial products (SMPs) that build up on the membrane surface play a significant role in the biofouling. In this study, the production of SMPs in a 32 L submerged AnMBR operated at three different organic loads (3.0, 4.1 and 1.2 kg chemical oxygen demand (COD)/m3d for phases 1, 2 and 3, respectively) during long-term operation of the reactor (144, 83 and 94 days) were evaluated. The samples were taken from both the permeate and the sludge at three different heights (0.14, 0.44 and 0.75 m). Higher production of SMPs was obtained in phase 2, which was proportional to the membrane fouling. There were no statistically significant differences (p > 0.05) in the SMPs extracted from sludge at different heights among the three phases. In the permeate of phases 1, 2 and 3, the membrane allowed the removal of 56%, 70% and 64% of the SMP concentration in the sludge. SMPs were characterized by molecular weight (MW). A bimodal behavior was obtained, where fractions prevailed with an MW < 1 kDa, associated with SMPs as utilization-associated products (UAPs) caused fouling by the pore-blocking mechanism. The chemical analysis found that, in the SMPs, the unknown COD predominated over the known COD, such as carbohydrates and proteins. These results suggest that further studies in SMP characterization should focus on the unknown COD fraction to understand the membrane fouling in AnMBR systems better.
Clarification of 1,3-Propanediol Fermentation Broths by Using a Ceramic Fine UF Membrane
Authors: Tomczak Wirginia , Gryta Marek
Published: October 2020

This work examined the use of a ceramic fine ultrafiltration (UF) membrane for the pre-treatment of 1,3-propanodiol (1,3-PD) fermentation broths. It has been demonstrated that the membrane used provides obtaining a high-quality, sterile permeate, which can be sequentially separated by other processes such as nanofiltration (NF) and membrane distillation (MD). Special attention was paid to the impact of the operational parameters on the membrane performance. The series of UF experiments under transmembrane pressure (TMP) from 0.1 to 0.4 MPa and feed flow rate (Q) from 200 to 400 dm3/h were performed. Moreover, the impact of the feed pH, in the range from 5 to 10, on the flux was investigated. It has been demonstrated that for fine UF, increasing the TMP is beneficial, and TMP equal to 0.4 MPa and Q of 400 dm3/h ensure the highest flux and its long-term stability. It has been shown that in terms of process efficiency, the most favorable pH of the broths is equal to 9.4. An effective and simple method of membrane cleaning was presented. Finally, the resistance-in-series model was applied to describe resistances that cause flux decline. Results obtained in this study can assist in improving the cost-effectiveness of the UF process of 1,3-PD fermentation broths.
Diversity of Acyl Homoserine Lactone Molecules in Anaerobic Membrane Bioreactors Treating Sewage at Psychrophilic Temperatures
Authors: Tabraiz Shamas , Shamurad Burhan , Petropoulos Evangelos , Charlton Alex , Mohiudin Obaidullah , Danish Khan Mohammad , Ekwenna Emeka , Sallis Paul
Published: October 2020

This study explores the types of acyl homoserine lactone (AHL) and their concentrations in different compartments of different conventional anaerobic bioreactors: (i) an upflow anaerobic membrane bioreactor (UAnMBR, biofilm/mixed liquor (sludge)); (ii) an anaerobic membrane bioreactor (AnMBR, biofilm/mixed liquor (sludge)); and (iii) an upflow sludge blanket (UASB, sludge only), all operating at 15 °C. Ten types of the AHL, namely C4-HSL, 3-oxo-C4-HSL, C6-HSL, 3-oxo-C6-HSL, C8-HSL, 3-oxo-C8-HSL, C10-HSL, 3-oxo-C10-HSL, C12-HSL, and 3-oxo-C12-HSL, which were investigated in this study, were found in UAnMBR and UASB, whilst only six of them (C4-HSL, 3-oxo-C4-HSL, C8-HSL, C10-HSL, 3-oxo-C10-HSL, and C12-HSL) were found in AnMBR. Concentrations of total AHL were generally higher in the biofilm than the sludge for both membrane bioreactors trialed. C10-HSL was the predominant AHL found in all reactors (biofilm and sludge) followed by C4-HSL and C8-HSL. Overall, the UAnMBR biofilm and sludge had 10-fold higher concentrations of AHL compared to the AnMBR. C10-HSL was only correlated with bacteria (p < 0.05), whilst other types of AHL were correlated with both bacteria and archaea. This study improves our understanding of AHL-mediated Quorum Sensing (QS) in the biofilms/sludge of UAnMBR and AnMBR, and provides new information that could contribute to the development of quorum quenching anti-fouling strategies in such systems.
Effect of Intercritical Annealing and Austempering on the Microstructure and Mechanical Properties of a High Silicon Manganese Steel
Authors: Franceschi Mattia , Pezzato Luca , Gennari Claudio , Fabrizi Alberto , Polyakova Marina , Konstantinov Dmitry , Brunelli Katya , Dabalà Manuele
Published: October 2020

High Silicon Austempered steels (AHSS) are materials of great interest due to their excellent combination of high strength, ductility, toughness, and limited costs. These steel grades are characterized by a microstructure consisting of ferrite and bainite, accompanied by a high quantity retained austenite (RA). The aim of this study is to analyze the effect of an innovative heat treatment, consisting of intercritical annealing at 780 °C and austempering at 400 °C for 30 min, on the microstructure and mechanical properties of a novel high silicon steel (0.43C-3.26Si-2.72Mn wt.%). The microstructure was characterized by optical and electron microscopy and XRD analysis. Hardness and tensile tests were performed. A multiphase ferritic-martensitic microstructure was obtained. A hardness of 426 HV and a tensile strength of 1650 MPa were measured, with an elongation of 4.5%. The results were compared with those ones obtained with annealing and Q&T treatments.
The Effect of Hydrogen on the Nanoindentation Behavior of Heat Treated 718 Alloy
Authors: Stenerud Gaute , Hajilou Tarlan , Olsen Jim Stian , Taji Iman , Barnoush Afrooz , Johnsen Roy
Published: October 2020

In this study, the effect of precipitates on the surface mechanical properties in the presence of hydrogen (H) is investigated by in situ electrochemical nanoindentation. The nickel superalloy 718 is subjected to three different heat treatments, leading to different sizes of the precipitates: (i) solution annealing (SA) to eliminate all precipitates, (ii) the as-received (AR) sample with fine, dispersed precipitates, and (iii) the over-aged (OA) specimen with coarser precipitates. The nanoindentation is performed using a conical tip, and a new method of reverse imaging is employed to calculate the nano-hardness. The results show that the hardness of the SA sample is significantly affected by H diffusion. However, it could be recovered by removing the H from its matrix by applying an anodic potential. Since the precipitates in the OA and AR samples are different, they are influenced by H differently. The hardness increase for the OA sample is more significant in −1200mV, while for the AR specimen, the H is more effective in −1500mV. In addition, the pop-in load is reduced when the samples are exposed to cathodic charging, and it cannot be fully recovered by switching to an anodic potential.
Microstructure and Mechanical Properties of Co-Cr-Mo-Si-Y-Zr High Entropy Alloy
Authors: Glowka Karsten , Zubko Maciej , Świec Paweł , Prusik Krystian , Albrecht Robert , Dercz Grzegorz , Loskot Jan , Witala Bartosz , Stróż Danuta
Published: October 2020

Presented work was focused on obtaining new, up to our knowledge, non-described previously in the literature high entropy Co15Cr15Mo25Si15Y15Zr15 alloy to fill in the knowledge gap about the six-elemental alloys located in the adjacent to the center of phase diagrams. Material was obtained using vacuum arc melting. Phase analysis revealed the presence of a multi-phase structure. Scanning electron microscopy microstructure analysis revealed the existence of three different phases with partially dendritic structures. Chemical analysis showed that all phases consist of all six principal elements—however, with different proportions. Transmission electron microscopy microstructure analysis confirmed the presence of amorphous and nanocrystalline areas, as well as their mixture. For the studied alloy, any phase transformation and solid-state crystallization were not revealed in the temperature range from room temperature up to 1350 °C. Nanoindentation measurements revealed high nanohardness (13(2) GPa and 18(1) GPa for dendritic and interdendritic regions, respectively) and relatively low Young’s modulus (185(23) GPa and 194(9) GPa for dendritic and interdendritic regions, respectively) of the observed phases.