bluuebunny/crossref_metadata_2025 huggingface dataset:
Dielectric Elastomer Actuator-Based Multifunctional Smart Window for Transparency Tuning and Noise Absorption
Authors: Shrestha Milan , Lau Gih-Keong , Asundi Anand , Lu Zhenbo
Published: January 2021

Soft actuators are compliant material-based devices capable of producing large deformation upon external stimuli. Dielectric elastomer actuators (DEA) are a type of soft actuator that operates on voltage stimuli. Apart from soft robotics, these actuators can serve many novel applications, for example, tunable optical gratings, lenses, diffusers, smart windows and so on. This article presents our current work on tunable smart windows which can regulate the light transmittance and the sound absorption. This smart window can promote daylighting while maintaining privacy by electrically switching between transparent and opaque. As a tunable optical surface scatters, it turns transparent with smooth surfaces like a flat glass; but it turns ‘opaque’ (translucent) with the micro-rough surface. The surface roughness is varied employing surface micro-wrinkling or unfolding using dielectric elastomer actuation. Moreover, this smart window is equipped with another layer of transparent micro-perforated dielectric elastomer actuator (DEA), which acts like Helmholtz resonators serving as a tunable and broader sound absorber. It can electrically tune its absorption spectrum to match the noise frequency for maximum acoustic absorption. The membrane tension and perforation size are tuned using DEA activation to tune its acoustic resonant frequency. Such a novel smart window can be made as cheap as glass due to its simple all-solid-state construction. In future, they might be used in smart green buildings and could potentially enhance urban livability.
Numerical Analysis of Flow across Brush Elements Based on a 2-D Staggered Tube Banks Model
Authors: Song Xiaolei , Liu Meihong , Hu Xiangping , Wang Xueliang , Liao Taohong , Sun Junfeng
Published: January 2021

In order to improve efficiency in turbomachinery, brush seal replaces labyrinth seals widely in the secondary air system. A 2-d staggered tube bank model is adopted to simulate the gas states and the pressure character in brush seal, and computational fluid dynamics (CFD) is used to solve the model in this paper. According to the simulation results, the corrected formula of the Euler number and dimensionless pressure are given. The results show that gas expands when flow through the bristle pack, and the gas expansion closes to an isotherm process. The dynamic pressure increases with decreasing static pressure. The Euler number can reflect the seal performance of brush seals in leakage characteristics. Compared with increasing the number of rows, the reduction of the gap is a higher-efficiency method to increase the Euler number. The Euler number continually increases as the gap decreases. However, with the differential pressure increasing, Euler number first increases and then decreases as the number of rows increases. Finally, the pressure distribution on the surface of end rows is asymmetric, and it may increase the friction between the bristles and the back plate.
Mortality of Pandrug-Resistant Klebsiella pneumoniae Bloodstream Infections in Critically Ill Patients: A Retrospective Cohort of 115 Episodes
Authors: Papadimitriou-Olivgeris Matthaios , Bartzavali Christina , Georgakopoulou Alexandra , Kolonitsiou Fevronia , Papamichail Chrisavgi , Spiliopoulou Iris , Christofidou Myrto , Fligou Fotini , Marangos Markos
Published: January 2021

Background: The increased frequency of bacteraemias caused by pandrug-resistant Klebsiella pneumoniae (PDR-Kp) has significant implications. The aim of the present study was to identify predictors associated with mortality of PDR-Kp bacteraemias. Methods: Patients with monomicrobial bacteraemia due to PDR-Kp were included. K. pneumoniae was considered PDR if it showed resistance to all available groups of antibiotics. Primary outcome was 30-day mortality. Minimum inhibitory concentrations (MICs) of meropenem, tigecycline, fosfomycin, and ceftazidime/avibactam were determined by Etest, whereas for colistin, the broth microdilution method was applied. blaKPC, blaVIM, blaNDM, and blaOXA genes were detected by PCR. Results: Among 115 PDR-Kp bacteraemias, the majority of infections were primary bacteraemias (53; 46.1%), followed by catheter-related (35; 30.4%). All isolates were resistant to tested antimicrobials. blaKPC was the most prevalent carbapenemase gene (98 isolates; 85.2%). Thirty-day mortality was 39.1%; among 51 patients with septic shock, 30-day mortality was 54.9%. Multivariate analysis identified the development of septic shock, Charlson comorbidity index, and bacteraemia other than primary or catheter-related as independent predictors of mortality, while a combination of at least three antimicrobials was identified as an independent predictor of survival. Conclusions: Mortality of PDR-Kp bloodstream infections was high. Administration of at least three antimicrobials might be beneficial for infections in critically ill patients caused by such pathogens.
Maternal Urinary Metal and Metalloid Concentrations in Association with Oxidative Stress Biomarkers
Authors: Ashrap Pahriya , Watkins Deborah J. , Milne Ginger L. , Ferguson Kelly K. , Loch-Caruso Rita , Fernandez Jennifer , Rosario Zaira , Vélez-Vega Carmen M. , Alshawabkeh Akram , Cordero José F. , Meeker John D.
Published: January 2021

Metal exposure has been associated with a wide range of adverse birth outcomes and oxidative stress is a leading hypothesis of the mechanism of action of metal toxicity. We assessed the relationship between maternal exposure to essential and non-essential metals and metalloids in pregnancy and oxidative stress markers, and sought to identify windows of vulnerability and effect modification by fetal sex. In our analysis of 215 women from the PROTECT birth cohort study, we measured 14 essential and non-essential metals in urine samples at three time points during pregnancy. The oxidative stress marker 8-iso-prostaglandin F2α (8-iso-PGF2α) and its metabolite 2,3-dinor-5,6-dihydro-15-15-F2t-IsoP, as well as prostaglandin F2α (PGF2α), were also measured in the same urine samples. Using linear mixed models, we examined the main effects of metals on markers of oxidative stress as well as the visit-specific and fetal sex-specific effects. After adjustment for covariates, we found that a few urinary metal concentrations, most notably cesium (Cs) and copper (Cu), were associated with higher 8-iso-PGF2α with effect estimates ranging from 7.3 to 14.9% for each interquartile range, increase in the metal concentration. The effect estimates were generally in the same direction at the three visits and a few were significant only among women carrying a male fetus. Our data show that higher urinary metal concentrations were associated with elevated biomarkers of oxidative stress. Our results also indicate a potential vulnerability of women carrying a male fetus.
Antitussive, Antioxidant, and Anti-Inflammatory Effects of a Walnut (Juglans regia L.) Septum Extract Rich in Bioactive Compounds
Authors: Fizeșan Ionel , Rusu Marius Emil , Georgiu Carmen , Pop Anca , Ștefan Maria-Georgia , Muntean Dana-Maria , Mirel Simona , Vostinaru Oliviu , Kiss Béla , Popa Daniela-Saveta
Published: January 2021

The antitussive, antioxidant, and anti-inflammatory effects of a walnut (Juglans regia L.) septum extract (WSE), rich in bioactive compounds were investigated using the citric acid aerosol-induced cough experimental model in rodents. Wistar male rats were treated orally for three days with distilled water (control), codeine (reference), and WSE in graded doses. On the third day, all rats were exposed to citric acid aerosols, the number of coughs being recorded. Each animal was sacrificed after exposure, and blood and lung tissue samples were collected for histopathological analysis and the assessment of oxidative stress and inflammatory biomarkers. The results of the experiment showed a significant antitussive effect of WSE, superior to codeine. This activity could be due to cellular protective effect and anti-inflammatory effect via the stimulation of the antioxidant enzyme system and the decrease of IL-6 and CXC-R1 concentration in the lung tissue of WSE-treated animals. The antioxidant and anti-inflammatory effects of WSE were confirmed by biochemical assays and histopathological analysis. This is the first scientific study reporting the antitussive effect of walnut septum, a new potential source of non-opioid antitussive drug candidates, and a valuable bioactive by-product that could be used in the treatment of respiratory diseases.
Experimental Study of Coaxial Jets Mixing Enhancement Using Synthetic Jets
Authors: Zhang Binglong , Liu He , Li Yangyang , Liu Hui , Dong Jinzhong
Published: January 2021

Synthetic jets perpendicular to the mainstream have been used to experimentally study the coaxial jets mixing enhancement in this paper. The parameters of coaxial jets such as vorticity, streamwise velocity, radial velocity, Reynolds shear stress, and turbulence intensity are measured using the particle image velocimetry (PIV) and hot wire anemometers. The distribution characteristics of these parameters with and without synthetic jets were obtained. The mechanism of coaxial jets mixing enhancement using synthetic jets was summarized by analyzing these experimental results, and it was also found that the momentum coefficient was the most critical factor for jets mixing enhancement. The comparative experiments fully verified the mechanism, showing that with an appropriate momentum coefficient, the synthetic jets significantly enhanced coaxial jets mixing.
Atomic Concealment Due to Loss of Coherence of the Incident Beam of Projectiles in Collision Processes
Authors: Barrachina Raúl O. , Navarrete Francisco , Ciappina Marcelo F.
Published: January 2021

In the study of collision processes, a series of conditions is usually assumed. One of them is that the beam of projectiles is coherent in lengths greater than those of the targets against which it strikes. However, recent experimental results and theoretical analyzes have shown that this assumption can not only fail, but that it is possible to manipulate the coherence length experimentally to go from a coherent situation to an incoherent one. The most conspicuous and studied manifestation of such loss of coherence is the disappearance of interference effects. However, in the present work we show that a strong decrease can also occur in the magnitude of the cross section, not only differential but also total, due to an atomic concealment effect.
A Literature Review of Naturally Ventilated Public Hospital Wards in Tropical Climate Countries for Thermal Comfort and Energy Saving Improvements
Authors: Rahman Noor Muhammad Abd , Haw Lim Chin , Fazlizan Ahmad
Published: January 2021

The tropical climate with its high average temperatures throughout the year affects the thermal comfort of buildings, especially for naturally ventilated spaces. The government’s move to turn hospitals into green buildings is seen in line with the global commitment to conserve the environment and the country’s current policy of supporting sustainable development. To achieve this goal, energy efficiency and thermal comfort need to be given priority in the focus on hospital planning and implementation for a better quality of the indoor environment. This literature review has led to the need to improve thermal comfort in natural ventilated wards in government hospitals. Some wards are built without air conditioning to save on construction costs, reduce utility costs through low energy consumption, as well as the need for infection control and airborne infections. However, current climate change requires a special study of thermal comfort in wards that use natural ventilation. An innovative solution is proposed to solve the problem statement identified in the reviewed literature through the application of solar PV/T systems and heat pumps. This hybrid system re-uses the heat energy (cogeneration) generated from solar PV panels to be cooled by heat pumps and is then pumped into the ward for cooling purposes. The proposed system has the potential to improve thermal comfort in natural ventilation wards and increase efficiency of the solar PV system for optimal electricity generation as well as improve the overall energy performance of buildings through low-energy cooling systems. It is not only solving the thermal comfort issue but also avoid the use of extra energy for cooling by optimizing the renewable energy.
Investigating the Effect of Dust Accumulation on the Solar Reflectivity of Coating Materials for Cool Roof Applications
Authors: Saber Hamed H. , Hajiah Ali E. , Alshehri Saleh A. , Hussain Hussain J.
Published: January 2021

Cool roofs use reflective materials or coatings to reflect a portion of the incident solar radiation. This results in a lowering the surface temperature of the cool roof compared to black roofs, and thus helps reduce the cooling energy loads during the summer season. The research reported in this paper was conducted to assess experimentally and numerically the performance of cool and black roofs that were subjected to the hot, humid and dusty climate of Jubail Industrial City (JIC). This paper focused on characterizing one of the important properties of reflective coating material (RCM), which is its solar reflectivity. In this study, the effect of dust/dirt accumulation on the solar reflectivity of the RCM was investigated at different exposure times to the natural weathering conditions of JIC. The test results showed that dust and dirt can significantly contribute in reducing the solar reflectivity of the RCM. As such, a number of cleaning processes were conducted on the surface of the RCM so as to increase its solar reflectivity. The effect of each cleaning process on the solar reflectivity of the RCM was investigated. Finally, this paper provides a test protocol and procedure for characterizing the dust concentration/intensity on the surfaces of the RCM and cleaning this material after different exposure times to a natural and polluted climate.
Life Cycle Assessment of Residential Air Conditioners Considering the Benefits of Their Use: A Case Study in Indonesia
Authors: Karkour Selim , Ihara Tomohiko , Kuwayama Tadahiro , Yamaguchi Kazuki , Itsubo Norihiro
Published: January 2021

The global demand for air conditioners (ACs) has more than tripled since 1990, with 1.6 billion units currently in use. With the rapid economic and population growth of countries located in the hottest parts in the world, this trend is likely to continue in the future. The aim of this study was to show the benefits of introducing air conditioners with different materials or different technologies such as inverters with high energy-saving performance on the environment and human health in Indonesia. To evaluate the environmental impacts of the different technologies, a cradle-to-grave life cycle assessment (LCA) of air conditioners was conducted using the life-cycle impact assessment method based on endpoint modeling (LIME3). As expected, the use stage has the largest global warming potential (GWP), representing more than 90% of the impact, whereas copper and nickel have the most important impact in terms of resource consumption (about 50%). We found that the impacts are heavily dependent on the country’s energy mix, but reduction can be achieved by introducing better technologies. The integration factors from LIME3 were then applied to estimate the external cost of each model; the results showed that the use stage also has the most influence. Even though the impact of climate change is important, air pollution impact must be seriously considered as its impact was found to be the highest (about 60% of the total impact). The external cost was finally compared to the possible benefits produced by the introduction of air conditioning technologies during their 10-year life cycle. We found that the impacts are twice that of the benefit for the best model (USD 2003 vs. 1064); however, the novelty of this study is that the benefit was also considered. In the future, developing countries should promote AC models with inverters, refrigerants with low global warming impact such as natural refrigerants, and encourage the recycling of units as soon as possible. The energy mix for electricity production is also a key parameter to consider.
Systematic Identification and Analysis of Circular RNAs of Japanese Flounder (Paralichthys olivaceus) in Response to Vibrio anguillarum Infection
Authors: Ning Xianhui , Sun Li
Published: January 2021

Circular RNA (circRNA) is a new class of non-coding RNA that is structured into a closed loop without polyadenylation. Recent studies showed that circRNAs are involved in the host immune response to pathogen infection. Japanese flounder (Paralichthys olivaceus), an important economical marine fish cultured in north Asia, is affected by Vibrio anguillarum, a pathogenic bacterium that can infect a large number of fish. In this study, we systematically explored the circRNAs in the spleen of V. anguillarum-infected flounder at different infection time points. A total of 6581 circRNAs were identified, 148 of which showed differential expression patterns after V. anguillarum infection and were named DEcirs. Most of the DEcirs were strongly time-specific. The parental genes of the DEcirs were identified and functionally classified into diverse pathways, including immune-related pathways. Among the immune-related DEcirs, seven were predicted to sponge 18 targeted miRNAs that were differentially expressed during V. anguillarum infection (named DETmiRs). Further analysis showed that the DEcirs and their corresponding DETmiRs intertwined into complicated immune related networks. These results indicate that in flounder, circRNAs are regulated by V. anguillarum and form interactive networks with mRNAs and miRNAs that likely play important roles in the immune defense against pathogen infection.
Twenty Years of Leading the Way among Cohort Studies in Community-Driven Outreach and Engagement: Jackson State University/Jackson Heart Study
Authors: Addison Clifton , Campbell Jenkins Brenda , White Monique , Thigpen Odom Darcel , Fortenberry Marty , Wilson Gregory , McCoy Pamela , Young Lavon , Woodberry Clevette , Herron Kathryn , Clark Jermal , Payton Marinelle , LaVigne Donna
Published: January 2021

Background: History has recorded the tremendous concerns and apprehension expressed by African Americans about participating in research studies. This review enumerates the collaborative techniques that were utilized by the Jackson State University (JSU) Jackson Heart Study (JHS) community-focused team to facilitate recruitment and retention of the JHS cohort and to implement health education and health promotion in the JHS communities. Methods: This review describes the evolution of the JSU JHS community initiatives, an innovative community-driven operation, during the period 1999–2018. Results: JSU JHS community-focused investigators published approximately 20 manuscripts, including community-led research and publications with community lead authors and co-authors, research and publications in collaboration with other JHS staff, through other JSU-funded projects. The JSU JHS community-focused unit also initiated the JHS Community Training Activities, developed the Community Health Advisory Network (CHAN), and trained and certified 137 Community Health Advisors. In addition, the JSU JHS community-focused unit developed the Collaborative Community Science Model (CCSM) that symbolized its approach to community engagement and outreach, and a Trust Scale for ascertaining African Americans’ willingness to engage in biomedical research collaborations. Conclusion: This review offers educators, public health professionals, and research investigators a useful starting point for the development, selection, or improvement of techniques to motivate, inspire, and engage community residents in a community–academia partnership that yielded maximum benefits in the areas of health education, health promotion and interventions, and biomedical research. Substantial, meaningful community engagement is possible when prioritizing elimination of health disparities and long-term improvement in health care access in the target populations.
Development and Evaluation of a Screening Scale for Indirect Trauma Caused by Media Exposure to Social Disasters
Authors: Choi Eun Young , Choi Seung-Hye , Lee Haeyoung
Published: January 2021

As a result of mass media development, disaster-related information, such as the severity of damage, can be easily shared; thus, the issue of consequent indirect trauma has become as important as that of direct trauma. This study developed a scale to measure the degree of indirect trauma caused by media exposure to social disasters and then verified this scale’s reliability and validity. Initial items were developed through a literature review; 39 items were selected by examining their content validity and conducting a pretest. To verify the scale’s validity and reliability, exploratory factor analyses were conducted, and Cronbach’s alpha coefficients were calculated. The explanatory power of the screening scale developed through this study was 62.2%. The scale was ultimately composed of three factors comprising 24 items. Through exploratory factor analyses, factors were identified as “psychological, physical, and behavioral responses to social disasters” (factor 1), “moral resentment due to social disasters” (factor 2), and “a sense of threat to life due to social disasters” (factor 3). Regarding internal reliability, Cronbach’s alpha values ranged between 0.85 and 0.96. Future studies with expanded participant populations are suggested, which could further verify the scale’s validity and reliability and complement its shortcomings.
Comorbidities at Diagnosis, Survival, and Cause of Death in Patients with Chronic Lymphocytic Leukemia: A Population-Based Study
Authors: Villavicencio Alicia , Solans Marta , Zacarías-Pons Lluís , Vidal Anna , Puigdemont Montse , Roncero Josep Maria , Saez Marc , Marcos-Gragera Rafael
Published: January 2021

This study aimed to examine the prevalence of comorbidities in patients diagnosed with chronic lymphocytic leukemia (CLL), and to assess its influence on survival and cause-specific mortality at a population-based level. Incident CLL cases diagnosed in the Girona province (Spain) during 2008–2016 were extracted from the Girona Cancer Registry. Rai stage and presence of comorbidities at diagnosis, further categorized using the Charlson comorbidity index (CCI), were obtained from clinical records. Observed (OS) and relative survival (RS) were estimated and Cox’s proportional hazard models were used to explore the impact of comorbidity on mortality. Among the 400 cases included in the study, 380 (99.5%) presented at least one comorbidity at CLL diagnosis, with diabetes without end organ damage (21%) being the most common disease. 5-year OS and RS were 68.8 (95% CI: 64.4–73.6) and 99.5 (95% CI 3.13–106.0), respectively, which decreased markedly with increasing CCI, particularly in patients with CCI ≥ 3. Multivariate analysis identified no statistically significant association between the CCI and overall CLL-related or CLL-unrelated mortality. In conclusion, a high CCI score negatively influenced the OS and RS of CLL patients, yet its effect on mortality was statistically non-significant when also considering age and the Rai stage.
Physical Activity and Daily Routine among Children Aged 0–12 during the COVID-19 Pandemic in Spain
Authors: Cachón-Zagalaz Javier , Zagalaz-Sánchez M.ª Luisa , Arufe-Giráldez Víctor , Sanmiguel-Rodríguez Alberto , González-Valero Gabriel
Published: January 2021

The COVID-19 pandemic has impacted the lives of many people. Objective: The aim of the present study was to analyse the physical activity (PA) and daily routine among children (0–12 years) during lockdown and to establish the main relationships among the variables. Methods: A quantitative study with a descriptive–comparative and cross-sectional design carried out. The sample, selected for convenience, consisted of 837 Spanish children aged 0–12. The “Children and confinement” questionnaire was used, distributed electronically through Google Forms and social networks and activated for 45 days. The individuals participating in this study were mainly children (50.2%) who were in primary education (44.8%). Predominantly, the families of participants were biparental (87.9%), with established routines and schedules (85.7%). Results and conclusions: The use of digital screens is an important part of children’s daily routine. Their daily activities were practiced for more than three–six years, with more by girls. The time children devoted to sleep was directly proportional to the time they devoted to physical activity and indirectly proportional to the time they spent watching screens. The children who slept the most were those aged zero–three years, especially girls, who belonged to large families. The levels of physical activity in the sample were low, as were the times spent on activities such as music or games.
Knowledge of Emergency Management of Avulsed Teeth among Italian Dentists-Questionnaire Study and Next Future Perspectives
Authors: Mazur Marta , Jedliński Maciej , Janiszewska-Olszowska Joanna , Ndokaj Artnora , Ardan Roman , Nardi Gianna Maria , Marasca Roberto , Ottolenghi Livia , Polimeni Antonella , Vozza Iole
Published: January 2021

(1) Background: In Italy, about one fourth of all schoolchildren experience a trauma to the permanent dentition. Management of avulsion trauma is challenging and requires adherence to clinical protocols. The aim of this study was to investigate the management knowledge of avulsed teeth among Italian dentists and to promote the guidelines’ dissemination through the use of new social media. (2) Methods: The survey was carried out during the COVID-19 lockdown in Italy (March–May 2020). The questionnaire was sent anonymously to a total of 600 dentists. The questionnaire consisted of two parts. Part A—demographic and professional data and Part B—management of traumatic avulsion. (3) Results: The response rate was 50.6% and the mean fraction of correct responses was 0.524. Issues related to the therapeutic management of avulsed teeth were shown to be not well understood by the respondents. Professionals with qualifications in dentistry and those who declared to know the guidelines responded better, while other demographic and professional factors were insignificant. (4) Conclusions: Italian dentists’ knowledge of the management of avulsion trauma should be improved. Educational programs and campaigns must be undertaken to improve their awareness and adherence to the Italian and international guidelines.
Controlling COVID-19 Outbreaks with Financial Incentives
Authors: Lee Chaeyoung , Kwak Soobin , Kim Junseok
Published: January 2021

In this paper, we consider controlling coronavirus disease 2019 (COVID-19) outbreaks with financial incentives. We use the recently developed susceptible-unidentified infected-confirmed (SUC) epidemic model. The unidentified infected population is defined as the infected people who are not yet identified and isolated and can spread the disease to susceptible individuals. It is important to quickly identify and isolate infected people among the unidentified infected population to prevent the infectious disease from spreading. Considering financial incentives as a strategy to control the spread of disease, we predict the effect of the strategy through a mathematical model. Although incentive costs are required, the duration of the disease can be shortened. First, we estimate the unidentified infected cases of COVID-19 in South Korea using the SUC model, and compute two parameters such as the disease transmission rate and the inverse of the average time for confirming infected individuals. We assume that when financial incentives are provided, there are changes in the proportion of confirmed patients out of unidentified infected people in the SUC model. We evaluate the numbers of confirmed and unidentified infected cases with respect to one parameter while fixing the other estimated parameters. We investigate the effect of the incentives on the termination time of the spread of the disease. The larger the incentive budget is, the faster the epidemic will end. Therefore, financial incentives can have the advantage of reducing the total cost required to prevent the spread of the disease, treat confirmed patients, and recover overall economic losses.
Preface from the Guest Editor of Special Issue “Simple Substances of Non-Metals: Molecular Structures Modeling with Using DFT and More Advanced Methods of Quantum Chemistry”
Authors: Mikhailov Oleg V.
Published: January 2021

According to the traditional definition of the concept of “simple substance” adopted in chemistry, it is as a chemical compound, the structural unit of which (molecule, ion, radical, the link of the polymer chain, the unit cell of the crystal lattice, etc [...]
Clinical and Molecular Insights in Erythropoiesis Regulation of Signal Transduction Pathways in Myelodysplastic Syndromes and β-Thalassemia
Authors: Parisi Sarah , Finelli Carlo , Fazio Antonietta , De Stefano Alessia , Mongiorgi Sara , Ratti Stefano , Cappellini Alessandra , Billi Anna Maria , Cocco Lucio , Follo Matilde Y. , Manzoli Lucia
Published: January 2021

Erythropoiesis regulation is essential in normal physiology and pathology, particularly in myelodysplastic syndromes (MDS) and β-thalassemia. Several signaling transduction processes, including those regulated by inositides, are implicated in erythropoiesis, and the latest MDS or β-thalassemia preclinical and clinical studies are now based on their regulation. Among others, the main pathways involved are those regulated by transforming growth factor (TGF)-β, which negatively regulates erythrocyte differentiation and maturation, and erythropoietin (EPO), which acts on the early-stage erythropoiesis. Also small mother against decapentaplegic (SMAD) signaling molecules play a role in pathology, and activin receptor ligand traps are being investigated for future clinical applications. Even inositide-dependent signaling, which is important in the regulation of cell proliferation and differentiation, is specifically associated with erythropoiesis, with phospholipase C (PLC) and phosphatidylinositol 3-kinase (PI3K) as key players that are becoming increasingly important as new promising therapeutic targets. Additionally, Roxadustat, a new erythropoiesis stimulating agent targeting hypoxia inducible factor (HIF), is under clinical development. Here, we review the role and function of the above-mentioned signaling pathways, and we describe the state of the art and new perspectives of erythropoiesis regulation in MDS and β-thalassemia.
Double Mutant Cycles as a Tool to Address Folding, Binding, and Allostery
Authors: Pagano Livia , Toto Angelo , Malagrinò Francesca , Visconti Lorenzo , Jemth Per , Gianni Stefano
Published: January 2021

Quantitative measurement of intramolecular and intermolecular interactions in protein structure is an elusive task, not easy to address experimentally. The phenomenon denoted ‘energetic coupling’ describes short- and long-range interactions between two residues in a protein system. A powerful method to identify and quantitatively characterize long-range interactions and allosteric networks in proteins or protein–ligand complexes is called double-mutant cycles analysis. In this review we describe the thermodynamic principles and basic equations that underlie the double mutant cycle methodology, its fields of application and latest employments, and caveats and pitfalls that the experimentalists must consider. In particular, we show how double mutant cycles can be a powerful tool to investigate allosteric mechanisms in protein binding reactions as well as elusive states in protein folding pathways.
Hepatic Encephalopathy in the 21st Century: Still an Emerging Topic
Authors: Ridola Lorenzo , Riggio Oliviero
Published: January 2021

Why write about hepatic encephalopathy (HE) in the twenty-first century [...]
Preventive Maintenance of a k-out-of-n System with Applications in Subsea Pipeline Monitoring
Authors: Rykov Vladimir , Kochueva Olga , Farkhadov Mais
Published: January 2021

Environmental safety issues are of particular importance when we design and operate underwater transport systems. To ensure the transport systems function safely, special systems to monitor their condition are being created. Underwater pipeline monitoring systems should continuously operate to detect and prevent emergency and pre-emergency situations in a timely manner. The purpose of this article is to demonstrate the possibility of using a mathematical model of a k-out-of-n system to support decision-making in the preventive maintenance of an unmanned underwater vehicle to monitor the condition of a subsea pipeline. The novelty and feature of this study are that we investigate a strategy of preventive maintenance for a model of a k-out-of-n system, where failures depend not only on the number but also on the location of the failed components in the system. The method to solve this problem, based on the distribution of the members of the variational series of the failing components, is also new. Since the distributions of the system component lifetimes are usually known with an accuracy of only one or two moments, we paid special attention to how sensitive the decision making about preventive maintenance is to the shape of the distributions. Numerical examples are conducted in order to support the theoretical investigations of the paper. The results of the study are applied to specific equipment to monitor the state of the outer surface of the pipeline.
Simulating Destructive and Constructive Morphodynamic Processes in Steep Beaches
Authors: Kombiadou Katerina , Costas Susana , Roelvink Dano
Published: January 2021

Short-term beach morphodynamics are typically modelled solely through storm-induced erosion, disregarding post-storm recovery. Yet, the full cycle of beach profile response is critical to simulating and understanding morphodynamics over longer temporal scales. The XBeach model is calibrated using topographic profiles from a reflective beach (Faro Beach, in S. Portugal) during and after the incidence of a fierce storm (Emma) that impacted the area in early 2018. Recovery in all three profiles showed rapid steepening of the beachface and significant recovery of eroded volumes (68–92%) within 45 days after the storm, while berm heights reached 4.5–5 m. Two calibration parameters were used (facua and bermslope), considering two sets of values, one for erosive (Hm0 ≥ 3 m) and one for accretive (Hm0 < 3 m) conditions. A correction of the runup height underestimation by the model in surfbeat mode was necessary to reproduce the measured berm elevation and morphology during recovery. Simulated profiles effectively capture storm erosion, but also berm growth and gradual recovery of the profiles, showing good skill in all three profiles and recovery phases. These experiments will be the basis to formulate event-scale simulations using schematized wave forcing that will allow to calibrate the model for longer-term changes.
Study on Reactive Power Compensation Strategies for Long Distance Submarine Cables Considering Electrothermal Coordination
Authors: Liu Gang , Fan Mingming , Wang Pengyu , Zheng Ming
Published: January 2021

Long-distance high voltage alternating current (AC) submarine cables are widely used to connect offshore wind farms and land power grids. However, the transmission capacity of the submarine cable is limited by the capacitive charging current. This paper analyzes the impacts of reactive power compensation in different positions on the current distribution on long-distance submarine cable transmission lines, and tests the rationality of the existing reactive power compensation schemes based on electrothermal coordination (ETC). Research shows that compensation at the sending end has obvious impacts on current distribution along the cable, and the maximum current occurs at the sending or receiving end. Moreover, the reactive power compensation at sending end will reduce the current at receiving end of the line. On the contrary, it will increase the current at sending end. Compared with the directly buried laying method of the submarine cable in the landing section, the cable trench laying method can increase the cable ampacity of the landing section and reduce the reactive power compensation capacity at the sending end. The ampacity is the current representation of the thermal limits of the cable. ETC exploits the cable ampacity to coordinate current distribution on transmission lines under existing reactive power compensation schemes, thus optimizing the reactive power compensation schemes and avoiding the bottleneck point of cable ampacity.
Modeling Dynamic Processes of Mondego Estuary and Óbidos Lagoon Using Delft3D
Authors: Mendes Joana , Ruela Rui , Picado Ana , Pinheiro João Pedro , Ribeiro Américo Soares , Pereira Humberto , Dias João Miguel
Published: January 2021

Estuarine systems currently face increasing pressure due to population growth, rapid economic development, and the effect of climate change, which threatens the deterioration of their water quality. This study uses an open-source model of high transferability (Delft3D), to investigate the physics and water quality dynamics, spatial variability, and interrelation of two estuarine systems of the Portuguese west coast: Mondego Estuary and Óbidos Lagoon. In this context, the Delft3D was successfully implemented and validated for both systems through model-observation comparisons and further explored using realistically forced and process-oriented experiments. Model results show (1) high accuracy to predict the local hydrodynamics and fair accuracy to predict the transport and water quality of both systems; (2) the importance of the local geomorphology and estuary dimensions in the tidal propagation and asymmetry; (3) Mondego Estuary (except for the south arm) has a higher water volume exchange with the adjacent ocean when compared to Óbidos Lagoon, resulting from the highest fluvial discharge that contributes to a better water renewal; (4) the dissolved oxygen (DO) varies with water temperature and salinity differently for both systems. On the one hand, for Mondego Estuary during winter the DO levels mainly fluctuate with salinity. On the other hand, for Óbidos Lagoon, DO distribution is determined by both water temperature and salinity. During summer, the high residence time and water temperature limit the DO levels in both systems. The high transferability and superior stability of Delft3D make this model a foundation for realistic simulation and research of distinct estuarine systems, giving support to their maintenance and restoration.
Experimental Investigation and Modeling of Damage Accumulation of EN-AW 2024 Aluminum Alloy under Creep Condition at Elevated Temperature
Authors: Tomczyk Adam , Seweryn Andrzej
Published: January 2021

The paper is focused on creep-rupture tests of samples made of the 2024 alloy in the T3511 temper under uniaxial tensile stress conditions. The basic characteristics of the material at the temperatures of 100, 200 and 300 °C were determined, such as the Young’s modulus E, yield point σy, ultimate tensile strength σc and parameters K and n of the Ramberg–Osgood equation. Creep tests were performed for several different levels of nominal axial stress (load) at each temperature. It was observed that in the process of creep to failure at 200 and 300 °C, as the stress decreases, the creep time increases and, at the same time, the strain at rupture increases. However, such a regularity is maintained until a certain transition stress value σt is reached. Reducing the stress below this value results in a decreased value of the strain at rupture. A simple model of creep damage accumulation was proposed for the stress range above the transient value. In this model, the increase in the isotropic damage state variable was made dependent on the value of axial stress and the increase in plastic axial strain. Using the results of experimental creep-rupture tests and the failure condition, the parameters of the proposed model were determined. The surface of fractures obtained in the creep tests with the use of SEM technology was also analyzed.
State-of-the-Art Review of Capabilities and Limitations of Polymer and Glass Fibers Used for Fiber-Reinforced Concrete
Authors: Shafei Behrouz , Kazemian Maziar , Dopko Michael , Najimi Meysam
Published: January 2021

The concrete industry has long been adding discrete fibers to cementitious materials to compensate for their (relatively) low tensile strengths and control possible cracks. Extensive past studies have identified effective strategies to mix and utilize the discrete fibers, but as the fiber material properties advance, so do the properties of the cementitious composites made with them. Thus, it is critical to have a state-of-the-art understanding of not only the effects of individual fiber types on various properties of concrete, but also how those properties are influenced by changing the fiber type. For this purpose, the current study provides a detailed review of the relevant literature pertaining to different fiber types considered for fiber-reinforced concrete (FRC) applications with a focus on their capabilities, limitations, common uses, and most recent advances. To achieve this goal, the main fiber properties that are influential on the characteristics of cementitious composites in the fresh and hardened states are first investigated. The study is then extended to the stability of the identified fibers in alkaline environments and how they bond with cementitious matrices. The effects of fiber type on the workability, pre- and post-peak mechanical properties, shrinkage, and extreme temperature resistance of the FRC are explored as well. In offering holistic comparisons, the outcome of this study provides a comprehensive guide to properly choose and utilize the benefits of fibers in concrete, facilitating an informed design of various FRC products.
Elicitation of Antimicrobial Active Compounds by Streptomyces-Fungus Co-Cultures
Authors: Nicault Matthieu , Zaiter Ali , Dumarcay Stéphane , Chaimbault Patrick , Gelhaye Eric , Leblond Pierre , Bontemps Cyril
Published: January 2021

The bacteria of the genus Streptomyces and Basidiomycete fungi harbor many biosynthetic gene clusters (BGCs) that are at the origin of many bioactive molecules with medical or industrial interests. Nevertheless, most BGCs do not express in standard lab growth conditions, preventing the full metabolic potential of these organisms from being exploited. Because it generates biotic cues encountered during natural growth conditions, co-culture is a means to elicit such cryptic compounds. In this study, we explored 72 different Streptomyces-fungus interaction zones (SFIZs) generated during the co-culture of eight Streptomyces and nine fungi. Two SFIZs were selected because they showed an elicitation of anti-bacterial activity compared to mono-cultures. The study of these SFIZs showed that co-culture had a strong impact on the metabolic expression of each partner and enabled the expression of specific compounds. These results show that mimicking the biotic interactions present in this ecological niche is a promising avenue of research to explore the metabolic capacities of Streptomyces and fungi.
Hydroxyapatite-poly(d,l-lactide) Nanografts. Synthesis and Characterization as Bone Cement Additives
Authors: Goranova Kristina L. , Kattenhøj Sloth Overgaard Anne Kathrine , Gitsov Ivan
Published: January 2021

This paper reports the creation of hydroxyapatite/polyester nanografts by “graft-from” polymerization of d,l-lactide with [Ca5(OH)(PO4)3]2 as the initiator and tin(II)-2-ethylhexanoate as the catalyst. Model polymerizations were performed with cyclooctanol as initiator to confirm the grafting on the surface of the hydroxyapatite nanocrystals. Polymers with the highest molecular mass (Mn) between 4250 Da (cyclooctanol) and 6100 Da (hydroxyapatite) were produced. In both cases the molecular mass distributions of the polymers formed were monomodal. The materials obtained were characterized by size-exclusion chromatography, NMR and FT-IR spectroscopy, and thermal methods. Their suitability as additives for commercial bone cement (Simplex P Speedset, Stryker Orthopaedics) has been confirmed by thermal analysis techniques and mechanical testing. The results obtained show that addition of the hydroxyapatite/ polyester nanografts improved both thermal and mechanical properties of the bone cement.
Advances in Antiviral Therapy for Subacute Sclerosing Panencephalitis
Authors: Hashimoto Koichi , Hosoya Mitsuaki
Published: January 2021

Subacute sclerosing panencephalitis (SSPE) is a late-onset, intractable, and fatal viral disease caused by persistent infection of the central nervous system by a mutant strain of the measles virus. Ribavirin intracerebroventricular therapy has already been administered to several SSPE patients in Japan based on fundamental and clinical research findings from our group, with positive therapeutic effects reported in some patients. However, the efficacy of this treatment approach has not been unequivocally established. Hence, development of more effective therapeutic methods using new antiviral agents is urgently needed. This review describes the current status of SSPE treatment and research, highlighting promising approaches to the development of more effective therapeutic methods.
From Natural Products to New Synthetic Small Molecules: A Journey through the World of Xanthones
Authors: Pinto Madalena M. M. , Palmeira Andreia , Fernandes Carla , Resende Diana I. S. P. , Sousa Emília , Cidade Honorina , Tiritan Maria Elizabeth , Correia-da-Silva Marta , Cravo Sara
Published: January 2021

This work reviews the contributions of the corresponding author (M.M.M.P.) and her research group to Medicinal Chemistry concerning the isolation from plant and marine sources of xanthone derivatives as well as their synthesis, biological/pharmacological activities, formulation and analytical applications. Although her group activity has been spread over several chemical families with relevance in Medicinal Chemistry, the main focus of the investigation and research has been in the xanthone family. Xanthone derivatives have a variety of activities with great potential for therapeutic applications due to their versatile framework. The group has contributed with several libraries of xanthones derivatives, with a variety of activities such as antitumor, anticoagulant, antiplatelet, anti-inflammatory, antimalarial, antimicrobial, hepatoprotective, antioxidant, and multidrug resistance reversal effects. Besides therapeutic applications, our group has also developed xanthone derivatives with analytical applications as chiral selectors for liquid chromatography and for maritime application as antifouling agents for marine paints. Chemically, it has been challenging to afford green chemistry methods and achieve enantiomeric purity of chiral derivatives. In this review, the structures of the most significant compounds will be presented.