bluuebunny/crossref_metadata_2025 huggingface dataset:
FollowMe: One Social Importance-Based Collaborative Scheme in MONs
Authors: Yuan Peiyan , Pang Xiaoxiao , Liu Ping , Zhang En
Published: April 2019

The performance of mobile opportunistic networks mainly relies on collaboration among nodes. Thus far, researchers have ignored the influence of node sociality on the incentive process, leading to poor network performance. Considering the fact that followers always imitate the behavior of superstars, this paper proposes FollowMe, which integrates the social importance of nodes with evolutionary game theory to improve the collaborative behavior of nodes. First, we use the prisoner’s dilemma model to establish the matrix of game gains between nodes. Second, we introduce the signal reference as a game rule between nodes. The number of nodes choosing different strategies in a game round is used to calculate the cumulative income of the node in combination with the probability formula. Finally, the Fermi function is used to determine whether the node updates the strategy. The simulation results show that, compared with the random update rule, the proposed strategy is more capable of promoting cooperative behavior between nodes to improve the delivery rate of data packets.
Pistacia terebinthus Resin as Yeast Immobilization Support for Alcoholic Fermentation
Authors: Kallis Michalis , Sideris Konstantinos , Kopsahelis Nikolaos , Bosnea Loulouda , Kourkoutas Yiannis , Terpou Antonia , Kanellaki Maria
Published: April 2019

A natural resin retrieved from Pistacia terebinthus tree was evaluated as an immobilization carrier of Saccharomyces cerevisiae AXAZ-1 cells targeting successive fermentation batches of sugar synthetic mediums. Fermentation times below 54 h were recorded at temperatures 28–14 °C. In total, 147 compounds were detected using gas chromatography-mass spectrometry (GC-MS) analysis, including alcohols, esters, ketones, aldehydes, acids, and terpenes. Principal component analysis indicated that the state of cells (free/immobilized) and the fermentation temperature primarily affected terpenes’ composition. Importantly, no spoilage of the fermented beverages was noted during 90 days of storage at room temperature, most likely due to the high content of extracted terpenoids and phenols (up to 579.01 mg L−1 and 171.8 mg gallic acid equivalent L−1, respectively). Likewise, the developed novel biocatalyst (yeast cells immobilized within Pistacia terebinthus resin) was suitable for the production of low alcohol beverages with an enhanced aromatic profile. The obtained results revealed that the proposed bioprocess shows great commercialization potential in the new fast-growing low-alcohol beverages sector.
Atmospheric Control of Deep Chlorophyll Maximum Development
Authors: Somavilla Raquel , Rodriguez Carmen , Lavín Alicia , Viloria Amaia , Marcos Elena , Cano Daniel
Published: April 2019

The evolution of the near-surface phytoplankton bloom towards a Deep Chlorophyll Maximum (DCM) in mid-latitudes and subpolar regions of the global ocean is a well-known biological feature. However, our knowledge about the exact mechanism that determines the end of the bloom and its irreversible evolution towards a DCM is still limited. In this work, combining satellite and in-situ oceanographic data together with reanalysis data, we investigate why and when this transition between the near-surface phytoplankton bloom and the development of a DCM occurs. For this aim, we investigate the links between changes in air-sea heat exchanges, the near-surface signature of phytoplankton bloom, and the water column vertical structure by calculating the mixed layer depth (MLD) and depth of the DCM on hydrographic and chlorophyll profiles. We find that the occurrence of the last convective mixing event (heat loss by the ocean surface) at the end of the spring which is able to reach the base of the MLD and inject new nutrients into the mixed layer marks the end of the near-surface bloom and its transition towards a DCM. Identified in this way, the spring bloom duration and the start of the transition towards a DCM can be systematically and objectively determined, providing sensitive indexes of climate and ecosystem variability.
Job Crafting as a Mediator between Work Engagement and Wellbeing Outcomes: A Time-Lagged Study
Authors: Robledo Enrique , Zappalà Salvatore , Topa Gabriela
Published: April 2019

This time-lagged study, using the framework of the JD-R model, tested the mediating role of job crafting measuring: at T1, work engagement, workaholism and emotional exhaustion; at T2, job crafting; and, at T3, flourishing, job performance and job satisfaction. Respondents were 443 Spanish employees working in different companies. Results show that job crafting mediates the relationship between work engagement and some of its outcomes (job performance and flourishing). In particular, the job crafting component ‘increasing structural job resources’ mediates the positive effect of work engagement on flourishing and job performance, and the job crafting component ‘increasing challenging demands’ mediates the positive effect of work engagement on job performance. No job crafting mediation is found between work engagement and job satisfaction.
Beyond Broadway: Analysis of Qualitative Characteristics of and Individual Responses to Creatively Able, a Music and Movement Intervention for Children with Autism
Authors: Lakes Kimberley D. , Neville Ross , Vazou Spyridoula , Schuck Sabrina E. B. , Stavropoulos Katherine , Krishnan Kavita , Gonzalez Irene , Guzman Kayla , Tavakoulnia Arya , Stehli Annamarie , Palermo Andrew
Published: April 2019

Movement in response to music represents one of the natural social environments in which physical activity occurs. The study of music and movement, including dance, requires a careful, holistic consideration of many features, which may include music, physical activity, motor learning, social engagement, emotion, and creativity. The overarching goal of this manuscript is to examine qualitative characteristics of and individual responses to a music and movement intervention (Creatively Able) for children with Autism Spectrum Disorder (ASD). We provide a description of Creatively Able, illustrating how the program design and physical and social environment were informed by children’s needs and preferences in order to provide an enriched environment in which to promote multiple systems in children with ASD. Using data from two pilot studies with 20 children with ASD, we illustrate how researchers can use observational research methods to measure important aspects of the social environment (e.g., children’s engagement during intervention sessions) as well as engagement of potential underlying behavioral mechanisms (e.g., self-regulation) that might reduce clinical symptoms. We further illustrate how individual responses to intervention (e.g., improvements in behaviors or symptoms) can be studied in physically active interventions. Our pilot study results showed group-level reductions in Stereotyped and Compulsive behaviors of 8% and 4%, respectively; posthoc analysis revealed that there were substantial individual differences in children’s responses to the intervention. This research illustrates robust methods that can be applied to intervention research to improve our understanding of important features of interventions that might help promote development in various domains, including executive functions and self-regulation.
Preventable Mortality in Regions of Slovakia—Quantification of Regional Disparities and Investigation of the Impact of Environmental Factors
Authors: Gavurova Beata , Toth Peter
Published: April 2019

Environmental health is among the priority areas of public health, and the current professional communities are intensively engaged with it. The main objective of the study is to quantify regional disparities of preventable mortality in Slovakia and to study the extent of the influence of selected environmental factors on changes in the development of its values. A cross-sectional linear regression model is used to quantify effects of environmental factors on the preventable mortality. Also, cluster analysis is used to identify regions with similar levels of air pollution. Environmental factors were selected based on the study of the World Health Organization. From the point of view of the influence of environmental factors on preventable mortality in the case of men, statistically significant connection to sewerage, SO2 production, and production of particulate matter was demonstrated. In the case of women, equally important factors showed connection to sewerage and SO2. The results of this study point to significant regional disparities in preventable mortality and a different degree of impact of environmental factors. Preventable mortality is above the Slovak average in most of the least-developed districts. Even in this group, there are significant differences.
Impact of the Global Budget Payment System on Expenditure of Cardiovascular Diseases: An Interrupted Time Series Analysis in Shanghai, China
Authors: Dou Guanshen , Zhang Yilin , He Yunzhen , Huang Qiaoyun , Ye Yingfeng , Zhang Xinyu , Wang Weibing , Ying Xiaohua
Published: April 2019

Since few studies evaluated the impact of the global budget payment system (GBPS) over time, and by expenditure type, this paper aims to evaluate the impact of the GBPS on expenditure of inpatients, and explores how hospitals curb the expenditure in patients with cardiovascular diseases (CVDs) in Shanghai. We built a time series model with the monthly expenditure of CVDs from 2009 to 2012. We evaluated the instant impact and trends impact of the GBPS and analyzed results based on medical expenditure types (e.g., drug, examination, cure, unclassified items), discharge number, and expenditure per capita. We found GBPS instantly dropped the medical expenditure by Chinese Yuan (CNY) 55.71 million (p < 0.001), and decreased the monthly increasing trend by CNY 4.23 million (p = 0.011). The discharge number had 10.4% instant reduction and 225.55 monthly decrease (p = 0.021) while the expenditure per capita experienced fewer changes. Moreover, the expenditure of drug and cure had an instant reduction of CNY 28.31 million and 16.28 million (p < 0.001). In conclusion, we considered the GBPS is an effective solution to control the expenditure of CVDs by decreasing the discharge number, and a focus on the drug and cure expenditures lead to greater spend reduction than other types of expenditures.
Surgical Risk on Patients with Coagulopathies: Guidelines on Hemophiliac Patients for Oro-Maxillofacial Surgery
Authors: Laino Luigi , Cicciù Marco , Fiorillo Luca , Crimi Salvatore , Bianchi Alberto , Amoroso Giulia , Monte Ines Paola , Herford Alan Scott , Cervino Gabriele
Published: April 2019

Background: Haemophilia is a disease of genetic origin, which causes a defect in blood coagulation. Under normal conditions, in the case of leakage from the blood vessels, the blood forms a clot that reduces or blocks the bleeding. This process involves the activation of several plasma proteins in a cascade-like species. Two of these proteins, produced in the liver, factor VIII and factor IX, are deficient or present a functional defect in people with haemophilia. Because of this deficit, the haemophiliacs easily suffer external and internal bleeding. Surgical treatment of these patients is to be observed, and often their treatment is delayed due to unclear guidelines and risks in treating these patients. The aim is to provide clear guidelines in the case of surgical treatment of these patients. Methods: In this study, we have considered all the guidelines that refer to the gold-maxillofacial surgery, focusing on the literature of the last 10 years. Results: Surely, this collection of guidelines will favor the choice of the clinician towards safer and predictable protocols. This study does not want to create a guideline but evaluates the literature of the last 10 years, and highlights the latest for the treatment of these patients., with the aim of informing the pathology and at the same time making the surgical maneuvers safer. Conclusions: Despite the research of literature has produced few results, it was nevertheless possible to draw up a guideline thanks to additional information extrapolated from textbooks and other scientific articles. According to the guidelines, it is possible to proceed to the treatment of these patients, if with appropriate therapy in a safe and risk-free manner.
Are Daycare Workers at a Higher Risk of Parvovirus B19 Infection? A Systematic Review and Meta-Analysis
Authors: Romero Starke Karla , Kofahl Marlen , Freiberg Alice , Schubert Melanie , Groß Mascha Luisa , Schmauder Stefanie , Hegewald Janice , Kämpf Daniel , Stranzinger Johanna , Nienhaus Albert , Seidler Andreas
Published: April 2019

Objective: In this systematic review, we aimed to summarize the evidence on the association between being a daycare educator working with children and the possible increased risk of parvovirus B19 infection compared to the general population. Methods: The Medline and Embase databases were searched using a defined search to find studies published since 2000. Two reviewers evaluated the search hits using predefined inclusion and exclusion criteria. The resulting studies were extracted and were assessed in eight domains of bias. A pooled relative risk (RR) of parvovirus infection for daycare workers compared to the general population was calculated. Results: After evaluating the 7781 search hits and manual search, four methodologically-adequate studies were identified: three cross-sectional studies and one retrospective cohort study. Of the three studies investigating the risk of infection, one evaluated parvovirus B19 seroconversion rates for daycare workers. There was an indication for an increased risk for daycare workers compared to the unexposed population (RR = 1.12, 95% CI 0.98–1.27) using prevalence estimators. Furthermore, daycare workers had a higher seroconversion rate compared to the unexposed population (RR = 2.63, 95% CI 1.27–5.45) in the low risk of bias study. Conclusions: Our findings suggest a higher risk of parvovirus B19 infection for daycare workers compared to an unexposed comparison population, which necessitate preventative efforts. Considering the underestimation of the occupational seroconversion risk by prevalence-based estimators, parvovirus B19 infections among daycare workers might mostly be occupationally acquired.
Development and Characteristics of Pancreatic Epsilon Cells
Authors: Sakata Naoaki , Yoshimatsu Gumpei , Kodama Shohta
Published: April 2019

Pancreatic endocrine cells expressing the ghrelin gene and producing the ghrelin hormone were first identified in 2002. These cells, named ε cells, were recognized as the fifth type of endocrine cells. Differentiation of ε cells is induced by various transcription factors, including Nk2 homeobox 2, paired box proteins Pax-4 and Pax6, and the aristaless-related homeobox. Ghrelin is generally considered to be a “hunger hormone” that stimulates the appetite and is produced mainly by the stomach. Although the population of ε cells is small in adults, they play important roles in regulating other endocrine cells, especially β cells, by releasing ghrelin. However, the roles of ghrelin in β cells are complex. Ghrelin contributes to increased blood glucose levels by suppressing insulin release from β cells and is also involved in the growth and proliferation of β cells and the prevention of β cell apoptosis. Despite increasing evidence and clarification of the mechanisms of ε cells over the last 20 years, many questions remain to be answered. In this review, we present the current evidence for the participation of ε cells in differentiation and clarify their characteristics by focusing on the roles of ghrelin.
Evaluation of Biological Response of STRO-1/c-Kit Enriched Human Dental Pulp Stem Cells to Titanium Surfaces Treated with Two Different Cleaning Systems
Authors: Conserva Enrico , Pisciotta Alessandra , Bertoni Laura , Bertani Giulia , Meto Aida , Colombari Bruna , Blasi Elisabetta , Bellini Pierantonio , de Pol Anto , Consolo Ugo , Carnevale Gianluca
Published: April 2019

Peri-implantitis—an infection caused by bacterial deposition of biofilm—is a common complication in dentistry which may lead to implant loss. Several decontamination procedures have been investigated to identify the optimal approach being capable to remove the bacterial biofilm without modifying the implant surface properties. Our study evaluated whether two different systems—Ni-Ti Brushes (Brush) and Air-Polishing with 40 µm bicarbonate powder (Bic40)—might alter the physical/chemical features of two different titanium surfaces—machined (MCH) and Ca++ nanostructured (NCA)—and whether these decontamination systems may affect the biological properties of human STRO-1+/c-Kit+ dental pulp stem cells (hDPSCs) as well as the bacterial ability to produce biofilm. Cell morphology, proliferation and stemness markers were analysed in hDPSCs grown on both surfaces, before and after the decontamination treatments. Our findings highlighted that Bic40 treatment either maintained the surface characteristics of both implants and allowed hDPSCs to proliferate and preserve their stemness properties. Moreover, Bic40 treatment proved effective in removing bacterial biofilm from both titanium surfaces and consistently limited the biofilm re-growth. In conclusion, our data suggest that Bic40 treatment may operatively clean smooth and rough surfaces without altering their properties and, consequently, offer favourable conditions for reparative cells to hold their biological properties.
Centella asiatica Protects d-Galactose/AlCl3 Mediated Alzheimer’s Disease-Like Rats via PP2A/GSK-3β Signaling Pathway in Their Hippocampus
Authors: Chiroma Samaila Musa , Baharuldin Mohamad Taufik Hidayat , Mat Taib Che Norma , Amom Zulkhairi , Jagadeesan Saravanan , Ilham Adenan Mohd , Mahdi Onesimus , Moklas Mohamad Aris Mohd
Published: April 2019

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder more prevalent among the elderly population. AD is characterised clinically by a progressive decline in cognitive functions and pathologically by the presence of neurofibrillary tangles (NFTs), deposition of beta-amyloid (Aβ) plaque and synaptic dysfunction in the brain. Centella asiatica (CA) is a valuable herb being used widely in African, Ayurvedic, and Chinese traditional medicine to reverse cognitive impairment and to enhance cognitive functions. This study aimed to evaluate the effectiveness of CA in preventing d-galactose/aluminium chloride (d-gal/AlCl3) induced AD-like pathologies and the underlying mechanisms of action were further investigated for the first time. Results showed that co-administration of CA to d-gal/AlCl3 induced AD-like rat models significantly increased the levels of protein phosphatase 2 (PP2A) and decreased the levels of glycogen synthase kinase-3 beta (GSK-3β). It was further observed that, CA increased the expression of mRNA of Bcl-2, while there was minimal effect on the expression of caspase 3 mRNA. The results also showed that, CA prevented morphological aberrations in the connus ammonis 3 (CA 3) sub-region of the rat’s hippocampus. The results clearly demonstrated for the first time that CA could alleviate d-gal/AlCl3 induced AD-like pathologies in rats via inhibition of hyperphosphorylated tau (P-tau) bio-synthetic proteins, anti-apoptosis and maintenance of cytoarchitecture.
Identification of a Novel PROP1 Mutation in a Patient with Combined Pituitary Hormone Deficiency and Enlarged Pituitary
Authors: Penta Laura , Bizzarri Carla , Panichi Michela , Novelli Antonio , Lepri Francesca Romana , Cappa Marco , Esposito Susanna
Published: April 2019

Growth hormone deficiency (GHD) can be present from the neonatal period to adulthood and can be the result of congenital or acquired insults. In addition, GHD can be classified into two types: isolated growth hormone deficiency (IGHD) and combined pituitary hormone deficiency (CPHD). CPHD is a disorder characterized by impaired production of two or more anterior and/or posterior pituitary hormones. Many genes implicated in CPHD remain to be identified. Better genetic characterization will provide more information about the disorder and result in important genetic counselling because a number of patients with hypopituitarism represent familial cases. To date, PROP1 mutations represent the most common known genetic cause of CPHD both in sporadic and familial cases. We report a novel mutation in the PROP1 gene in an infant with CPHD and an enlarged pituitary gland. Close long-term follow-up will reveal other possible hormonal defects and pituitary involution.
Self-Assembly of Metal Nanoclusters for Aggregation-Induced Emission
Authors: Wang Jianxing , Lin Xiangfang , Shu Tong , Su Lei , Liang Feng , Zhang Xueji
Published: April 2019

Aggregation-induced emission (AIE) is an intriguing strategy to enhance the luminescence of metal nanoclusters (NCs). However, the morphologies of aggregated NCs are often irregular and inhomogeneous, leading to instability and poor color purity of the aggregations, which greatly limit their further potential in optical applications. Inspired by self-assembly techniques, manipulating metal NCs into well-defined architectures has achieved success. The self-assembled metal NCs often exhibit enhancing emission stability and intensity compared to the individually or randomly aggregated ones. Meanwhile, the emission color of metal NCs becomes tunable. In this review, we summarize the synthetic strategies involved in self-assembly of metal NCs for the first time. For each synthetic strategy, we describe the self-assembly mechanisms involved and the dependence of optical properties on the self-assembly. Finally, we outline the current challenges to and perspectives on the development of this area.
Physiological Responses of Jurkat Lymphocytes to Simulated Microgravity Conditions
Authors: Morabito Caterina , Lanuti Paola , Caprara Giusy A. , Marchisio Marco , Bizzarri Mariano , Guarnieri Simone , Mariggiò Maria A.
Published: April 2019

The presence of microgravity conditions deeply affects the human body functions at the systemic, organ and cellular levels. This study aimed to investigate the effects induced by simulated-microgravity on non-stimulated Jurkat lymphocytes, an immune cell phenotype considered as a biosensor of the body responses, in order to depict at the cellular level the effects of such a peculiar condition. Jurkat cells were grown at 1 g or on random positioning machine simulating microgravity. On these cells we performed: morphological, cell cycle and proliferation analyses using cytofluorimetric and staining protocols—intracellular Ca2+, reactive oxygen species (ROS), mitochondria membrane potential and O2− measurements using fluorescent probes—aconitase and mitochondria activity, glucose and lactate content using colorimetric assays. After the first exposure days, the cells showed a more homogeneous roundish shape, an increased proliferation rate, metabolic and detoxifying activity resulted in decreased intracellular Ca2+ and ROS. In the late exposure time, the cells adapted to the new environmental condition. Our non-activated proliferating Jurkat cells, even if responsive to altered external forces, adapted to the new environmental condition showing a healthy status. In order to define the cellular mechanism(s) triggered by microgravity, developing standardized experimental approaches and controlled cell culture and simulator conditions is strongly recommended.
FK506 Induces Ligand-Independent Activation of the Bone Morphogenetic Protein Pathway and Osteogenesis
Authors: Sangadala Sreedhara , Devereaux Emily , Presciutti Steven , Boden Scott , Willett Nick
Published: April 2019

Osteoinductive bone morphogenetic proteins (BMPs), including BMP-2, have a unique capability of mediating bone formation both in orthotopic and ectopic locations. Immunosuppresive macrolides have been shown to potentiate BMP-2 activity through FKBP12, but these have yet to translate to effective osteoinductive therapies. Herein, we show the osteogenic activity of FK506 as a stand-alone agent in direct comparison to BMP-2 both in vitro and in vivo. FK506 was capable of producing stand-alone alkaline phosphatase induction in C2C12 cells comparable to that seen with rhBMP-2. FK506 treatment activated the BMP receptor, as shown by increased pSmad1/5 levels, and produced significantly higher mRNA levels of the early response genes in BMP and TGF-β pathways. Additionally, the FK506 induction of alkaline phosphatase was shown to be resistant to Noggin treatment. In vivo osteogenic activity of FK506 was tested by local delivery on a collagen sponge in an ectopic subcutaneous implantation model in the rat. Dose responses of FK506 showed increasing levels of ectopic mineralization comparable to the mineral volume produced by BMP-2 delivery. These findings suggest that the use of FK506 can enhance osteoblastic differentiation in vitro and can induce mineralization when delivered locally in vivo.
Co-Detection of miR-21 and TNF-α mRNA in Budding Cancer Cells in Colorectal Cancer
Authors: Møller Trine , James Jaslin P , Holmstrøm Kim , Sørensen Flemming B , Lindebjerg Jan , Nielsen Boye S
Published: April 2019

MicroRNA-21 (miR-21) is upregulated in many cancers including colon cancers and is a prognostic indicator of recurrence and poor prognosis. In colon cancers, miR-21 is highly expressed in stromal fibroblastic cells and more weakly in a subset of cancer cells, particularly budding cancer cells. Exploration of the expression of inflammatory markers in colon cancers revealed tumor necrosis factor alpha (TNF-α) mRNA expression at the invasive front of colon cancers. Surprisingly, a majority of the TNF-α mRNA expressing cells were found to be cancer cells and not inflammatory cells. Because miR-21 is positively involved in cell survival and TNF-α promotes necrosis, we found it interesting to analyze the presence of miR-21 in areas of TNF-α mRNA expression at the invasive front of colon cancers. For this purpose, we developed an automated procedure for the co-staining of miR-21, TNF-α mRNA and the cancer cell marker cytokeratin based on analysis of frozen colon cancer tissue samples (n = 4) with evident cancer cell budding. In all four cases, TNF-α mRNA was seen in a small subset of cancer cells at the invasive front. Evaluation of miR-21 and TNF-α mRNA expression was performed on digital slides obtained by confocal slide scanning microscopy. Both co-expression and lack of co-expression with miR-21 in the budding cancer cells was noted, suggesting non-correlated expression. miR-21 was more often seen in cancer cells than TNF-α mRNA. In conclusion, we report that miR-21 is not linked to expression of the pro-inflammatory cytokine TNF-α mRNA, but that miR-21 and TNF-α both take part in the cancer expansion at the invasive front of colon cancers. We hypothesize that miR-21 may protect both fibroblasts and cancer cells from cell death directed by TNF-α paracrine and autocrine activity.
Smart Integration of a DC Microgrid: Enhancing the Power Quality Management of the Neighborhood Low-Voltage Distribution Network
Authors: Ebrahim Ahmed F. , Saad Ahmed A. , Mohammed Osama
Published: April 2019

The fast development of the residential sector regarding the additional integration of renewable distributed energy sources and the modern expansion usage of essential DC electrical equipment may cause severe power quality problems. For example, the integration of rooftop photovoltaic (PV) may cause unbalance, and voltage fluctuation, which can add constraints for further PV integrations to the network, and the deployment of DC native loads with their nonlinear behavior adds harmonics to the network. This paper demonstrates the smart integration of a DC microgrid to the neighborhood low-voltage distribution network (NLVDN). The DC microgrid is connected to the NLVDN through a three-phase voltage source inverter (VSI), in which the VSI works as a distribution static compensator (DSTATCOM). Unlike previous STATCOM work in the literature, the proposed controller of the VSI of the DC smart building allows for many functions: (a) it enables bidirectional active/reactive power flow between the DC building and the AC grid at point of common coupling (PCC); (b) it compensates for the legacy unbalance in the distribution network, providing harmonics elimination and power factor correction capability at PCC; and (c) it provides voltage support at PCC. The proposed controller was validated by Matlab/Simulink and by experimental implementation at the lab.
Can We Predict Failure of Mitral Valve Repair?
Authors: Gasser Simone , von Stumm Maria , Sinning Christoph , Schaefer Ulrich , Reichenspurner Hermann , Girdauskas Evaldas
Published: April 2019

Objective: To identify echocardiographic and surgical risk factors for failure after mitral valve repair. Methods: We identified a total of 77 consecutive patients from our institutional mitral valve surgery database who required redo mitral valve surgery due to recurrence of mitral regurgitation after primary mitral valve repair. A control group of 138 patients who had a stable echocardiographic long-term result was included based on propensity score matching. Systematic analysis of echocardiographic parameters was performed before primary surgery; after mitral valve repair and prior to redo surgery. Risk factor analysis was performed using multivariate Cox regression model. Results: Redo surgery was associated with the presence of pulmonary hypertension ≥ 50 mmHg (p = 0.02), a mean transmitral gradient > 5 mmHg (p = 0.001), left ventricular ejection fraction ≤ 45% (p = 0.05) before surgery and mitral regurgitation ≥moderate at time of discharge (p = 0.002) in the whole cohort. Patients with functional mitral valve regurgitation had a higher tendency to undergo redo surgery if preoperative left ventricular end-diastolic diameter exceeded 65 mm (p = 0.043) and if postoperative tenting height exceeded 6 mm (p = 0.018). Low ejection fraction was not significantly associated with the need for redo mitral valve surgery in the functional subgroup. Conclusions: Recurrent mitral regurgitation is still a valuable problem and is associated with relevant perioperative mortality. Patients with severe mitral regurgitation should undergo early mitral valve repair surgery as long as systolic pulmonary artery pressure is low, left ventricular ejection fraction is preserved, and LVEED is deceeds 65 mm.
Production and Mechanical Characterization of Graphene Micro-Ribbons
Authors: Pastore Carbone Maria Giovanna , Tsoukleri Georgia , Manikas Anastasios C. , Makarona Eleni , Tsamis Christos , Galiotis Costas
Published: April 2019

Patterning of graphene into micro- and nano-ribbons allows for tunability in emerging fields such as flexible electronic and optoelectronic devices, and is gaining interest for the production of more efficient reinforcement for composite materials. In this work we fabricate micro-ribbons from graphene synthesized via chemical vapor deposition (CVD) by combining ultraviolet (UV) photolithography and dry etching oxygen plasma treatments. We used Raman spectral imaging to confirm the effectiveness of the patterning procedure, which is suitable for large-area patterning of graphene on wafer-scale, and confirms that the quality of graphene remains unaltered. The produced micro-ribbons were finally transferred and embedded into a polymeric matrix and the mechanical response was investigated by in-situ mechanical investigation combining Raman spectroscopy and tensile/compressive tests.
Perspective Change and Personality State Variability: An Argument for the Role of Self-Awareness and an Outlook on Bidirectionality (Commentary on Wundrack et al., 2018)
Authors: Jauk Emanuel , Kanske Philipp
Published: April 2019

In a recent article, Wundrack et al. (2018) put forward an elaborate and intriguing hypothesis on enhanced perspective-taking (Theory of Mind) ability as a consequence of higher personality state variability. While there is evidence in favor of this hypothesis, the clinical examples of bipolar disorder and borderline personality disorder, as highlighted by the authors, demonstrate that a high state variability can also be accompanied by a lower perspective-taking ability (as commonly observed in these disorders). We suggest that only those state changes which are initiated on a voluntary basis and are accompanied by self-awareness go along with a higher perspective-taking ability. Introducing self-awareness as a moderating factor might help explain seemingly conflicting findings related to the hypothesis proposed in the target article. Moreover, we argue that the direction of causality proposed in the target article is not the only conceivable one, and perspective-taking ability could also be a cause, not just a consequence, of personality state variability. Finally, we provide suggestions on how these hypotheses could be tested in future studies.
Sulfate Resistance of Recycled Aggregate Concrete with GGBS and Fly Ash-Based Geopolymer
Authors: Xie Jianhe , Zhao Jianbai , Wang Junjie , Wang Chonghao , Huang Peiyan , Fang Chi
Published: April 2019

There is a constant drive for the development of ultra-high-performance concrete using modern green engineering technologies. These concretes have to exhibit enhanced durability and incorporate energy-saving and environment-friendly functions. The object of this work was to develop a green concrete with an improved sulfate resistance. In this new type of concrete, recycled aggregates from construction and demolition (C&D) waste were used as coarse aggregates, and granulated blast furnace slag (GGBS) and fly ash-based geopolymer were used to totally replace the cement in concrete. This study focused on the sulfate resistance of this geopolymer recycled aggregate concrete (GRAC). A series of measurements including compression, X-ray diffraction (XRD), and scanning electron microscopy (SEM) tests were conducted to investigate the physical properties and hydration mechanisms of the GRAC after different exposure cycles in a sulfate environment. The results indicate that the GRAC with a higher content of GGBS had a lower mass loss and a higher residual compressive strength after the sulfate exposure. The proposed GRACs, showing an excellent sulfate resistance, can be used in construction projects in sulfate environments and hence can reduce the need for cement as well as the disposal of C&D wastes.
Controlling the Composition and Magnetic Properties of Nano-SrFe12O19 Powder Synthesized from Oily Cold Mill Sludge by the Citrate Precursor Method
Authors: Liu Bo , Zhang Shengen , Steenari Britt-Marie , Ekberg Christian
Published: April 2019

This paper proposes a new method for producing nano-SrFe12O19 powder by the citrate precursor route using solid waste as a source of iron. This solid iron-containing waste, which exists in the form of an oily sludge, is produced by a cold rolling mill. This sludge was first subjected to a process, including sulfuric acid leaching, oxidation, precipitation, and nitric acid leaching, to obtain an iron nitrate (Fe(NO3)3) solution. Next, the Fe(NO3)3 solution was mixed with a strontium nitrate (Sr(NO3)2) solution obtained by subjecting strontium carbonate to nitric acid leaching. Subsequently, citric acid, as chelating agent, and ammonia water, as precipitating agent, were added to the mixed solution to form a gel. The gel was dried and spontaneously combusted, then annealed at different temperatures for 2 h in flowing air. The effects of the Fe3+/Sr2+ molar ratio and annealing temperature on the formation, morphology, and magnetic properties of SrFe12O19 were investigated. The results showed that single-phase SrFe12O19 powder was obtained by decreasing the Fe3+/Sr2+ molar ratio from the stoichiometric value of 12 to 11.6 and increasing the annealing temperature to 1000 °C for 2 h. Adjustment of the Fe/Sr molar ratio to 12 and the annealing temperature to 900 °C enabled the magnetic properties to be optimized, including saturation magnetization (Ms) 80.2 emu/g, remanence magnetization (Mr) 39.8 emu/g, and coercive force (Hc) 6318 Oe.
Activated Carbon/Transition Metal (Ni, In, Cu) Hexacyanoferrate Nanocomposites for Cesium Adsorption
Authors: Kiener Julien , Limousy Lionel , Jeguirim Mejdi , Le Meins Jean-Marc , Hajjar-Garreau Samar , Bigoin Gaetan , Ghimbeu Camélia Matei
Published: April 2019

Transition metal hexacyanoferrate/microporous activated carbon composites were obtained using a simple successive impregnation approach. The effect of metal type (nickel, indium, or copper), and the carbon oxidation on the composite characteristics (porosity, metal structure, and particle size), as well as on the removal efficiency of cesium from aqueous solution was investigated. Successful formation of the desired metal hexacyanoferrate phase was achieved and the size of the metallic nanoparticles and their dispersion in the carbon network was found to depend on the metal type, with the indium and nickel-based materials exhibiting the smallest particle size distribution (< 10 nm). Adsorption tests performed under batch conditions demonstrate that the copper hexacyanoferrate/activated carbon composite present the highest cesium removal capacity from aqueous solution (74.7 mg·g−1) among the three studied metal-based nanocomposites. The carbon oxidation treatment leads to the increase in the number of functional groups to the detriment of the porosity but allows for an improvement in the Cs adsorption capacity. This indicates that the Cs adsorption process is governed by the carbon surface chemistry and not its porosity. Moreover, combining oxidized carbon support with copper hexacyanoferrate induces the highest cesium adsorption capacity (101.5 mg·g−1). This could be related to synergistic effects through two absorption mechanisms, i.e., a cation exchange mechanism of Cs with the metallic hexacyanoferrate phase and Cs adsorption via carbon oxygen surface groups, as demonstrated using X-ray photoelectron spectroscopy (XPS) analyses.
Microstructure and Mechanical Properties of Nanocrystalline Al-Zn-Mg-Cu Alloy Prepared by Mechanical Alloying and Spark Plasma Sintering
Authors: Cheng Jingfan , Cai Qizhou , Zhao Bingyi , Yang Songfeng , Chen Fei , Li Bing
Published: April 2019

In this study, Al, Zn, Mg and Cu elemental metal powders were chosen as the raw powders. The nanocrystalline Al-7Zn-2.5Mg-2.5Cu bulk alloy was prepared by mechanical alloying and spark plasma sintering. The effect of milling time on the morphology and crystal structure was investigated, as well as the microstructure and mechanical properties of the sintered samples. The results show that Zn, Mg and Cu alloy elements gradually dissolved in α-Al with the extension of ball milling time. The morphology of the ball-milled Al powder exhibited flaking, crushing and welding. When the ball milling time was 30 h, the powder particle size was 2–5 μm. The α-Al grain size was 23.2 nm. The lattice distortion was 0.156% causing by the solid solution of the metal atoms. The grain size of ball-milled powder grew during the spark plasma sintering process. The grain size of α-Al increased from 23.2 nm in the powder to 53.5 nm in the sintered sample during the sintering process after 30 h of ball milling. At the same time, the bulk alloy precipitated micron-sized Al2Cu and nano-sized MgZn2 in the α-Al crystal. With the extension of ball milling time, the compression strength, yield strength and Vickers hardness of spark plasma sintering (SPS) samples increased, while the engineering strain decreased. The compression strength, engineering strain and Vickers hardness of sintered samples prepared by 30 h milled powder were ~908 MPa, ~8.1% and ~235 HV, respectively. The high strength of the nanocrystalline Al-7Zn-2.5Mg-2.5Cu bulk alloy was attributed to fine-grained strengthening, dislocation strengthening and Orowan strengthening due to the precipitated second phase particles.
Machine Learning Techniques in Concrete Mix Design
Authors: Ziolkowski Patryk , Niedostatkiewicz Maciej
Published: April 2019

Concrete mix design is a complex and multistage process in which we try to find the best composition of ingredients to create good performing concrete. In contemporary literature, as well as in state-of-the-art corporate practice, there are some methods of concrete mix design, from which the most popular are methods derived from The Three Equation Method. One of the most important features of concrete is compressive strength, which determines the concrete class. Predictable compressive strength of concrete is essential for concrete structure utilisation and is the main feature of its safety and durability. Recently, machine learning is gaining significant attention and future predictions for this technology are even more promising. Data mining on large sets of data attracts attention since machine learning algorithms have achieved a level in which they can recognise patterns which are difficult to recognise by human cognitive skills. In our paper, we would like to utilise state-of-the-art achievements in machine learning techniques for concrete mix design. In our research, we prepared an extensive database of concrete recipes with the according destructive laboratory tests, which we used to feed the selected optimal architecture of an artificial neural network. We have translated the architecture of the artificial neural network into a mathematical equation that can be used in practical applications.
Double- and Multi-Femtosecond Pulses Produced by Birefringent Crystals for the Generation of 2D Laser-Induced Structures on a Stainless Steel Surface
Authors: Fraggelakis Fotis , Giannuzzi Giuseppe , Gaudiuso Caterina , Manek-Hönninger Inka , Mincuzzi Girolamo , Ancona Antonio , Kling Rainer
Published: April 2019

Laser-induced textures have been proven to be excellent solutions for modifying wetting, friction, biocompatibility, and optical properties of solids. The possibility to generate 2D-submicron morphologies by laser processing has been demonstrated recently. Employing double-pulse irradiation, it is possible to control the induced structures and to fabricate novel and more complex 2D-textures. Nevertheless, double-pulse irradiation often implies the use of sophisticated setups for modifying the pulse polarization and temporal profile. Here, we show the generation of homogeneous 2D-LIPSS (laser-induced periodic surface structures) over large areas utilizing a simple array of birefringent crystals. Linearly and circularly polarized pulses were applied, and the optimum process window was defined for both. The results are compared to previous studies, which include a delay line, and the reproducibility between the two techniques is validated. As a result of a systematic study of the process parameters, the obtained morphology was found to depend both on the interplay between fluence and inter-pulse delay, as well as on the number of incident pulses. The obtained structures were characterized via SEM (scanning electron microscopy) and atomic force microscopy. We believe that our results represent a novel approach to surface structuring, primed for introduction in an industrial environment.
Chlorophyll Derivatives from Marine Cyanobacteria with Lipid-Reducing Activities
Authors: Freitas Sara , Silva Natália Gonçalves , Sousa Maria Lígia , Ribeiro Tiago , Rosa Filipa , Leão Pedro N. , Vasconcelos Vitor , Reis Mariana Alves , Urbatzka Ralph
Published: April 2019

Marine organisms, particularly cyanobacteria, are important resources for the production of bioactive secondary metabolites for the treatment of human diseases. In this study, a bioassay-guided approach was used to discover metabolites with lipid-reducing activity. Two chlorophyll derivatives were successfully isolated, the previously described 132-hydroxy-pheophytin a (1) and the new compound 132-hydroxy-pheofarnesin a (2). The structure elucidation of the new compound 2 was established based on one- and two-dimensional (1D and 2D) NMR spectroscopy and mass spectrometry. Compounds 1 and 2 showed significant neutral lipid-reducing activity in the zebrafish Nile red fat metabolism assay after 48 h of exposure with a half maximal effective concentration (EC50) of 8.9 ± 0.4 µM for 1 and 15.5 ± 1.3 µM for 2. Both compounds additionally reduced neutral lipid accumulation in 3T3-L1 multicellular spheroids of murine preadipocytes. Molecular profiling of mRNA expression of some target genes was evaluated for the higher potent compound 1, which indicated altered peroxisome proliferator activated receptor gamma (PPARγ) mRNA expression. Lipolysis was not affected. Different food materials (Spirulina, Chlorella, spinach, and cabbage) were evaluated for the presence of 1, and the cyanobacterium Spirulina, with GRAS (generally regarded as safe) status for human consumption, contained high amounts of 1. In summary, known and novel chlorophyll derivatives were discovered from marine cyanobacteria with relevant lipid-reducing activities, which in the future may be developed into nutraceuticals.
Anverenes B–E, New Polyhalogenated Monoterpenes from the Antarctic Red Alga Plocamium cartilagineum
Authors: Shilling Andrew J. , von Salm Jacqueline L. , Sanchez Anthony R. , Kee Younghoon , Amsler Charles D. , McClintock James B. , Baker Bill J.
Published: April 2019

The subtidal red alga Plocamium cartilagineum was collected from the Western Antarctic Peninsula during the 2011 and 2017 austral summers. Bulk collections from specific sites corresponded to chemogroups identified by Young et al. in 2013. One of the chemogroups yielded several known acyclic halogenated monoterpenes (2–5) as well as undescribed compounds of the same class, anverenes B–D (6–8). Examination of another chemogroup yielded an undescribed cyclic halogenated monoterpene anverene E (9) as its major secondary metabolite. Elucidation of structures was achieved through one-dimensional (1D) and 2D nuclear magnetic resonance (NMR) spectroscopy and negative chemical ionization mass spectrometry. Compounds 1–9 show moderate cytotoxicity against cervical cancer (HeLa) cells.
Close Range Explosive Loading on Steel Column in the Framework of Anisotropic Viscoplasticity
Authors: Sielicki Piotr Witold , Sumelka Wojciech , Łodygowski Tomasz
Published: April 2019

The research was based on data obtained from experimental studies and aims in the challenge of mapping these results by a mathematical (phenomenological) model. The field experiments were performed on an H-section steel column supported by a reinforced concrete foundation and subjected to a close-in explosion. Numerical studies were carried out using Abaqus/Explicit code. The user subroutine VUMAT for metallic obstacle was also implemented, together with a coupled Eulerian–Lagrangian approach. The steel column failure recorded during real field tests versus computational results was examined and compared. It was crucial that, from the computational point of view, the obstacle reflected the generalized thermo-elasto-viscoplastic (GTEV) behavior of Perzyna’s type, including an anisotropic measure of damage.