bluuebunny/crossref_metadata_2025 huggingface dataset:
Chemical Modification of Microcin J25 Reveals New Insights on the Stereospecific Requirements for Antimicrobial Activity
Authors: Martin-Gómez Helena , Jorba Marta , Albericio Fernando , Viñas Miguel , Tulla-Puche Judit
Published: October 2019

In this study, microcin J25, a potent antimicrobial lasso peptide that acts on Gram-negative bacteria, was subjected to a harsh treatment with a base in order to interrogate its stability and mechanism of action and explore its structure-activity relationship. Despite the high stability reported for this lasso peptide, the chemical treatment led to the detection of a new product. Structural studies revealed that this product retained the lasso topology, but showed no antimicrobial activity due to the epimerization of a key residue for the activity. Further microbiological assays also demonstrated that it showed a high synergistic effect with colistin.
Mycobacterium tuberculosis β-Carbonic Anhydrases: Novel Targets for Developing Antituberculosis Drugs
Authors: Aspatwar Ashok , Kairys Visvaldas , Rala Sangeetha , Parikka Mataleena , Bozdag Murat , Carta Fabrizio , Supuran Claudiu T. , Parkkila Seppo
Published: October 2019

The genome of Mycobacterium tuberculosis (Mtb) encodes three β-carbonic anhydrases (CAs, EC 4.2.1.1) that are crucial for the life cycle of the bacterium. The Mtb β-CAs have been cloned and characterized, and the catalytic activities of the enzymes have been studied. The crystal structures of two of the enzymes have been resolved. In vitro inhibition studies have been conducted using different classes of carbonic anhydrase inhibitors (CAIs). In vivo inhibition studies of pathogenic bacteria containing β-CAs showed that β-CA inhibitors effectively inhibited the growth of pathogenic bacteria. The in vitro and in vivo studies clearly demonstrated that β-CAs of not only mycobacterial species, but also other pathogenic bacteria, can be targeted for developing novel antimycobacterial agents for treating tuberculosis and other microbial infections that are resistant to existing drugs. In this review, we present the molecular and structural data on three β-CAs of Mtb that will give us better insights into the roles of these enzymes in pathogenic bacterial species. We also present data from both in vitro inhibition studies using different classes of chemical compounds and in vivo inhibition studies focusing on M. marinum, a model organism and close relative of Mtb.
From Crosstalk between Immune and Bone Cells to Bone Erosion in Infection
Authors: Kumar Gaurav , Roger Pierre-Marie
Published: October 2019

Bone infection and inflammation leads to the infiltration of immune cells at the site of infection, where they modulate the differentiation and function of osteoclasts and osteoblasts by the secretion of various cytokines and signal mediators. In recent years, there has been a tremendous effort to understand the cells involved in these interactions and the complex pathways of signal transduction and their ultimate effect on bone metabolism. These crosstalk mechanisms between the bone and immune system finally emerged, forming a new field of research called osteoimmunology. Diseases falling into the category of osteoimmunology, such as osteoporosis, periodontitis, and bone infections are considered to have a significant implication in mortality and morbidity of patients, along with affecting their quality of life. There is a much-needed research focus in this new field, as the reported data on the immunomodulation of immune cells and their signaling pathways seems to have promising therapeutic benefits for patients.
Verification of 5-Aminolevurinic Radiodynamic Therapy Using a Murine Melanoma Brain Metastasis Model
Authors: Takahashi Junko , Nagasawa Shinsuke , Ikemoto Mitsushi J. , Sato Chikara , Sato Mari , Iwahashi Hitoshi
Published: October 2019

Melanoma is a highly aggressive cancer with a propensity for brain metastases. These can be treated by radiotherapy, but the radiation-resistant nature of melanoma makes the prognosis for melanoma patients with brain metastases poor. Previously, we demonstrated that treatment of mice with subcutaneous melanoma with 5-aminolevurinic acid (5-ALA) and X-rays in combination, (“radiodynamic therapy (RDT)”), instead of with 5-ALA and laser beams (“photodynamic therapy”), improved tumor suppression in vivo. Here, using the B16-Luc melanoma brain metastasis model, we demonstrate that 5-ALA RDT effectively treats brain metastasis. We also studied how 5-ALA RDT damages cells in vitro using a B16 melanoma culture. Cell culture preincubated with 5-ALA alone increased intracellular photosensitizer protoporphyrin IX. On X-ray irradiation, the cells enhanced their ∙OH radical generation, which subsequently induced γH2AX, a marker of DNA double-strand breaks in their nuclei, but decreased mitochondrial membrane potential. After two days, the cell cycle was arrested. When 5-ALA RDT was applied to the brain melanoma metastasis model in vivo, suppression of tumor growth was indicated. Therapeutic efficacy in melanoma treatment has recently been improved by molecular targeted drugs and immune checkpoint inhibitors. Treatment with these drugs is now expected to be combined with 5-ALA RDT to further improve therapeutic efficacy.
MiNgMatch—A Fast N-gram Model for Word Segmentation of the Ainu Language
Authors: Nowakowski Karol , Ptaszynski Michal , Masui Fumito
Published: October 2019

Word segmentation is an essential task in automatic language processing for languages where there are no explicit word boundary markers, or where space-delimited orthographic words are too coarse-grained. In this paper we introduce the MiNgMatch Segmenter—a fast word segmentation algorithm, which reduces the problem of identifying word boundaries to finding the shortest sequence of lexical n-grams matching the input text. In order to validate our method in a low-resource scenario involving extremely sparse data, we tested it with a small corpus of text in the critically endangered language of the Ainu people living in northern parts of Japan. Furthermore, we performed a series of experiments comparing our algorithm with systems utilizing state-of-the-art lexical n-gram-based language modelling techniques (namely, Stupid Backoff model and a model with modified Kneser-Ney smoothing), as well as a neural model performing word segmentation as character sequence labelling. The experimental results we obtained demonstrate the high performance of our algorithm, comparable with the other best-performing models. Given its low computational cost and competitive results, we believe that the proposed approach could be extended to other languages, and possibly also to other Natural Language Processing tasks, such as speech recognition.
Psychophysiological Measures of Reactance to Persuasive Messages Advocating Limited Meat Consumption
Authors: Spelt Hanne , Dijk Elisabeth Kersten-van , Ham Jaap , Westerink Joyce , IJsselsteijn Wijnand
Published: October 2019

Persuasive interventions can lose their effectiveness when a person becomes reactant to the persuasive messages—a state identified by feelings of anger and perceived threat to freedom. A person will strive to reestablish their threatened freedom, which is characterized by motivational arousal. Research suggests that the motivational state of psychological reactance can be observed in physiology. Therefore, the assessment of physiological reactions might help to identify reactance to persuasive messages and, thereby, could be an objective approach to personalize persuasive technologies. The current study investigates peripheral psychophysiological reactivity in response to persuasive messages. To manipulate the strength of the reactant response either high- or low-controlling language messages were presented to discourage meat consumption. The high-controlling language condition indeed evoked more psychological reactance, and sympathetic arousal did increase during persuasive messaging in heart rate and heart rate variability, although no clear relationship between physiological reactivity and self-reported psychological reactance was found. However, the evaluation of multiple linear models revealed that variance in self-reported psychological reactance was best explained by initial intentions in combination with cardiovascular reactivity. To conclude, considering physiological reactivity in addition to motivational state can benefit our understanding of psychological reactance.
Conceptual Encoding and Advanced Management of Leonardo da Vinci’s Mona Lisa: Preliminary Results
Authors: Amelio Alessia , Zarri Gian Piero
Published: October 2019

This paper describes a preliminary experiment concerning the use of advanced Artificial Intelligence/Knowledge Representation techniques to improve the present formalization/digitization procedures of Cultural Heritage assets—with reference, in particular, to all types of Cultural Heritage “iconographic” entities. In this context, in agreement with the recent proposal to characterize the digital description of Cultural Heritage items making use of the notion of “Cultural Heritage Digital Twin”, we are mainly concerned with the possibility to consider not only the external, “physical”, aspects of these iconographic items but also the “message” they convey in a more or less explicit way. For our experiment, some aspects of the Mona Lisa painting by Leonardo da Vinci have been formalized, along with their context, making use of NKRL, the “Narrative Knowledge Representation Language”. NKRL is, in reality, both a Knowledge Representation language and a full Computer Science environment, used to represent/manage in an advanced way “narrative” (in the widest meaning of this word) information. The initial results of the experiment are described in the paper, along with some thoughts about their possible interest and developments.
Genetics in the Honey Bee: Achievements and Prospects toward the Functional Analysis of Molecular and Neural Mechanisms Underlying Social Behaviors
Authors: Kohno Hiroki , Kubo Takeo
Published: October 2019

The European honey bee is a model organism for studying social behaviors. Comprehensive analyses focusing on the differential expression profiles of genes between the brains of nurse bees and foragers, or in the mushroom bodies—the brain structure related to learning and memory, and multimodal sensory integration—has identified candidate genes related to honey bee behaviors. Despite accumulating knowledge on the expression profiles of genes related to honey bee behaviors, it remains unclear whether these genes actually regulate social behaviors in the honey bee, in part because of the scarcity of genetic manipulation methods available for application to the honey bee. In this review, we describe the genetic methods applied to studies of the honey bee, ranging from classical forward genetics to recently developed gene modification methods using transposon and CRISPR/Cas9. We then discuss future functional analyses using these genetic methods targeting genes identified by the preceding research. Because no particular genes or neurons unique to social insects have been found yet, further exploration of candidate genes/neurons correlated with sociality through comprehensive analyses of mushroom bodies in the aculeate species can provide intriguing targets for functional analyses, as well as insight into the molecular and neural bases underlying social behaviors.
Analysis of miRNAs in the Heads of Different Castes of the Bumblebee Bombus lantschouensis (Hymenoptera: Apidae)
Authors: Liu Meijuan , Huang Jiaxing , Zhang Guangshuo , Liu Xiaofeng , An Jiandong
Published: October 2019

Bumblebees are important insect pollinators for many wildflowers and crops. MicroRNAs (miRNAs) are endogenous non-coding small RNAs that regulate different biological functions in insects. In this study, the miRNAs in the heads of the three castes of the bumblebee Bombus lantschouensis were identified and characterized by small RNA deep sequencing. The significant differences in the expression of miRNAs and their target genes were analyzed. The results showed that the length of the small RNA reads from males, queens, and workers was distributed between 18 and 30 nt, with a peak at 22 nt. A total of 364 known and 89 novel miRNAs were identified from the heads of the three castes. The eight miRNAs with the highest expressed levels in males, queens, and workers were identical, although the order of these miRNAs based on expression differed. The male vs. queen, male vs. worker, and worker vs. queen comparisons identified nine, fourteen, and four miRNAs with significant differences in expression, respectively. The different castes were clustered based on the differentially expressed miRNAs (DE miRNAs), and the expression levels of the DE miRNAs obtained by RT-qPCR were consistent with the read counts obtained through Solexa sequencing. The putative target genes of these DE miRNAs were enriched in 29 Gene Ontology (GO) terms, and catalytic activity was the most enriched GO term, as demonstrated by its association with 2837 target genes in the male vs. queen comparison, 3535 target genes in the male vs. worker comparison, and 2185 target genes in the worker vs. queen comparison. This study highlights the characteristics of the miRNAs in the three B. lantschouensis castes and will aid further studies on the functions of miRNAs in bumblebees.
A Subset of Odorant Receptors from the Desert Locust Schistocerca gregaria Is Co-Expressed with the Sensory Neuron Membrane Protein 1
Authors: Pregitzer Pablo , Jiang Xingcong , Lemke René-Sebastian , Krieger Jürgen , Fleischer Jörg , Breer Heinz
Published: October 2019

In the desert locust Schistocerca gregaria (S. gregaria), pheromones are considered to be crucial for governing important behaviors and processes, including phase transition, reproduction, aggregation and swarm formation. The receptors mediating pheromone detection in olfactory sensory neurons (OSNs) on the antenna of S. gregaria are unknown. Since pheromone receptors in other insects belong to the odorant receptor (OR) family and are typically co-expressed with the “sensory neuron membrane protein 1” (SNMP1), in our search for putative pheromone receptors of S. gregaria, we have screened the OR repertoire for receptor types that are expressed in SNMP1-positive OSNs. Based on phylogenetic analyses, we categorized the 119 ORs of S. gregaria into three groups (I–III) and analyzed a substantial number of ORs for co-expression with SNMP1 by two-color fluorescence in situ hybridization. We have identified 33 ORs that were co-expressed with SNMP1. In fact, the majority of ORs from group I and II were found to be expressed in SNMP1-positive OSNs, but only very few receptors from group III, which comprises approximately 60% of all ORs from S. gregaria, were co-expressed with SNMP1. These findings indicate that numerous ORs from group I and II could be important for pheromone communication. Collectively, we have identified a broad range of candidate pheromone receptors in S. gregaria that are not randomly distributed throughout the OR family but rather segregate into phylogenetically distinct receptor clades.
Exploring the Ability of Electronic Nose Technology to Recognize Interstitial Lung Diseases (ILD) by Non-Invasive Breath Screening of Exhaled Volatile Compounds (VOC): A Pilot Study from the European IPF Registry (eurIPFreg) and Biobank
Authors: Krauss Ekaterina , Haberer Jana , Maurer Olga , Barreto Guillermo , Drakopanagiotakis Fotios , Degen Maria , Seeger Werner , Guenther Andreas
Published: October 2019

Background: There is an increasing interest in employing electronic nose technology in the diagnosis and monitoring of lung diseases. Interstitial lung diseases (ILD) are challenging in regard to setting an accurate diagnosis in a timely manner. Thus, there is a high unmet need in non-invasive diagnostic tests. This single-center explorative study aimed to evaluate the usefulness of electronic nose (Aeonose®) in the diagnosis of ILDs. Methods: Exhaled volatile organic compound (VOC) signatures were obtained by Aeonose® in 174 ILD patients, 23 patients with chronic obstructive pulmonary disease (COPD), and 33 healthy controls (HC). Results: By dichotomous comparison of VOC’s between ILD, COPD, and HC, a discriminating algorithm was established. In addition, direct analyses between the ILD subgroups, e.g., cryptogenic organizing pneumonia (COP, n = 28), idiopathic pulmonary fibrosis (IPF, n = 51), and connective tissue disease-associated ILD (CTD-ILD, n = 25) were performed. Area under the Curve (AUC) and Matthews’s correlation coefficient (MCC) were used to interpret the data. In direct comparison of the different ILD subgroups to HC, the algorithms developed on the basis of the Aeonose® signatures allowed safe separation between IPF vs. HC (AUC of 0.95, MCC of 0.73), COP vs. HC (AUC 0.89, MCC 0.67), and CTD-ILD vs. HC (AUC 0.90, MCC 0.69). Additionally, to a case-control study design, the breath patterns of ILD subgroups were compared to each other. Following this approach, the sensitivity and specificity showed a relevant drop, which results in a poorer performance of the algorithm to separate the different ILD subgroups (IPF vs. COP with MCC 0.49, IPF vs. CTD-ILD with MCC 0.55, and COP vs. CT-ILD with MCC 0.40). Conclusions: The Aeonose® showed some potential in separating ILD subgroups from HC. Unfortunately, when applying the algorithm to distinguish ILD subgroups from each other, the device showed low specificity. We suggest that artificial intelligence or principle compound analysis-based studies of a much broader data set of patients with ILDs may be much better suited to train these devices.
Effects of Pet Insects on Cognitive Function among the Elderly: An fMRI Study
Authors: Park Ji-Yeon , Ko Hae-Jin , Kim A-Sol , Moon Ha-Na , Choi Hye-In , Kim Jin-Hee , Chang Yongmin , Kim Seong-Hyun
Published: October 2019

Animal-assisted therapy has positive effects on cognitive function, depression, performance ability, and social functioning in elderly patients. The aim of this study was to evaluate the effects of rearing pet insects on the cognitive function of healthy elderly participants, with fMRI (functional magnetic resonance imaging) being used for this purpose. Community-dwelling right-handed elderly women (≥60 years) with normal cognitive function were enrolled and randomized at a 1:1 ratio into two groups: insect-rearing and control (n = 16) groups, with the insect-rearing group being further classified into two groups for analysis according to the subjects’ scores in the Wisconsin Card Sorting Test, WCST) at the baseline fMRI: Insect-rearing group I with a relatively high score (n = 13), and insect-rearing group II with a relatively low score (n = 6). The insect-rearing groups received and reared crickets as pet insects for 8 weeks. The WCST consisted of two variations, a high level baseline (HLB) and semi-WCST version. There was a significant difference accuracy of the HLB–semi-WCST (p < 0.05) in insect-rearing group II after 8 weeks from the baseline test. In the fMRI analysis involving the WCST reaction test, increased activation was observed in the right dorsal lateral prefrontal cortex and parietal cortex in insect-rearing group II when the semi-WCST, rather than the HLB, was performed. Rearing pet insects showed positive effects on executive functions and performance improvement in elderly women. Further larger studies on the effects of pet insects on cognitive function are warranted.
Comment from the Editor to the Special Issue: “Periodontitis: From Dysbiotic Microbial Immune Response to Systemic Inflammation”
Authors: Oscarsson Jan , Johansson Anders
Published: October 2019

The human oral cavity contains a large number of different microbial habitats. When microbes from the oral indigenous flora colonize the interspace between the tooth and the connective tissue, they induce an inflammatory response. If the microbes are in sufficient numbers, and release components that cause an imbalance in the host inflammatory response, degenerative processes in the surrounding tissues are induced, ultimately resulting in periodontal disease. The disease progress depends on bacterial load, the composition of the microbial community, and host genetic factors. The two most studied periodontal pathogens, Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans express virulence factors, including proteases and exotoxins. Periodontal infections are also linked to the risk pattern of several systemic diseases. We would like to shed light on the mechanisms behind periodontitis and the associations of periodontal infections with systemic inflammation. Seven articles are included in this Special Issue and cover several pathogenic processes in the periodontal infection with capacity to cause imbalance in the host response. Highlights from each of the published papers are summarized and discussed below.
Cytobiology of Human Prostate Cancer Cells and Its Clinical Applications
Authors: Ishii Kenichiro
Published: October 2019

The number of males diagnosed with prostate cancer (PCa) is increasing all over the world [...]
Synthesis, Characterization and Photocatalytic Activity of N-doped Cu2O/ZnO Nanocomposite on Degradation of Methyl Red
Authors: Gaim Yohannes Teklemariam , Tesfamariam Gebrekidan Mebrahtu , Nigussie Gebretinsae Yeabyo , Ashebir Mengstu Etay
Published: October 2019

In this study, a N-doped Cu2O/ZnO nanocomposite was prepared by a co-precipitation and thermal decomposition technique from CuCl2, 2H2O, ZnSO4, 7H2O and CO(NH2)2 as precursors. The as-synthesized nanocomposites were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared analysis (FT–IR) and an ultraviolet–visible (UV–Vis) reflectance spectrometer. From the XRD diffractogram of N-doped Cu2O/ZnO nanocomposite, cubic and hexagonal wurtzite crystal structures of Cu2O, and ZnO, respectively were identified. The UV-vis reflectance spectra illustrated that the absorption edge of N-doped Cu2O/ZnO nanocomposite is more extended to the longer wavelength than ZnO, Cu2O and Cu2O/ZnO nanomaterials. FT–IR bands confirmed the presence of ZnO, Cu2O, and nitrogen in the N-doped Cu2O/ZnO nanocomposite. Photocatalytic activity of the as-synthesized nanocomposite was tested for methyl red degradation using sunlight as an energy source by optimizing the concentration of the dye and amount of the catalyst loaded. The degradation efficiency was greater in N-doped Cu2O/ZnO nanocomposite as compared to ZnO, Cu2O and Cu2O/ZnO nanomaterials. This is due to the coupling of the semiconductors which increases the absorption and exploitation capability of solar light and increases the charge separation as well. Besides that, nitrogen doping can extend absorption of light to the visible region by decreasing the energy gap. Therefore, N-doped Cu2O/ZnO nanocomposite is a solar light-active photocatalyst which can be used in the degradation of organic pollutants.
Watching the Beach Steadily Disappearing: The Evolution of Understanding of Retrogressive Breach Failures
Authors: Mastbergen Dick R. , Beinssen Konrad , Nédélec Yves
Published: October 2019

Retrogressive breach failures or coastal flow slides occur naturally in the shoreface in fine sands near dynamic tidal channels or rivers. They sometimes retrogress into beaches, shoal margins and riverbanks where they can threaten infrastructure and cause severe coastal erosion and flood risk. Ever since the first reports were published in the Netherlands over a century ago, attempts have been made to understand the geo-mechanical mechanism of flow slides. In this paper we have established that events, observed during the active phase, are characterized by a slow but steady retrogression into the shoreline, often continuing for many hours. This can be explained by the breaching mechanism, as will be clarified in this paper. Recently, further evidence has become available in the form of video footage of active events in Australia and elsewhere, often publicly posted on the internet. All these observations justify the new term ‘retrogressive breach failure’ (RBF event). The mechanism has been confirmed in flume tests and in a field experiment. With a better understanding of the geo-mechanical mechanism, current protection methods can be better understood, and new defense strategies can be envisaged. In writing this paper, we hope that the coastal science and engineering communities will better recognize and understand these intriguing natural events.
Response of a Porous Seabed around an Immersed Tunnel under Wave Loading: Meshfree Model
Authors: Han Shuang , Jeng Dong-Sheng , Tsai Chia-Cheng
Published: October 2019

Seabed instability surrounding an immersed tunnel is a vital engineering issue regarding the design and maintenance for submarine tunnel projects. In this study, a numerical model based on the local radial basis function collocation method (LRBFCM) is developed to evaluate the seabed behaviour in a marine environment, in which the seabed is treated as the porous medium and governed by Biot’s “ u − p ” approximation. As for the flow field above the seabed, the VARANS equations are used to simulate the fluid motion and properties. The present model is validated with analytical solutions and experimental data which show a good capacity of the integrated model. Both wave and current loading are considered in this study. Parametric studies are carried out to investigate the effects of wave characteristics and soil properties. Based on the numerical results, the maximum liquefaction depth around the immersed tunnel could be deeper under the wave loading with long wave period (T) and large wave height (H). Moreover, a seabed with lower permeability ( K s ) and degree of saturation ( S r ) is more likely to be liquefied.
Use of Engineering Mathematics for Ship Design
Authors: Fragassa Cristiano , dos Santos Elizaldo Domingues , Vannucchi de Camargo Felipe
Published: October 2019

With over that 70% of the Earth submerged by seas, continents separated by oceans, two thousand major islands scattered throughout the World, hundreds of thousands of kilometers of navigable rivers, maritime or fluvial transport surely represents one of the most important ways of moving people, goods, and wealth around the globe [...]
ISA 701 and Materiality Disclosure as Methods to Minimize the Audit Expectation Gap
Authors: Iwanowicz Tomasz , Iwanowicz Bartłomiej
Published: October 2019

Purpose: The main purpose of this paper is to determine how particular audit firms deal with ISA 701 requirements and the society expectations towards reporting the materiality levels. Additionally, the aim of this paper is to range the assertions in terms of the frequency of their occurrence. Design/methodology/approach: The tested sample consisted of 317 companies listed on Warsaw (158 companies) or London (159 companies) stock exchange. The analysis was divided into companies from the following ten market indexes (WIGs): construction, IT, real estate, food, media, oil and gas, mining, energy, automotive and chemicals. The research was executed based on the analysis of annual consolidated financial statements (annual reports) and independent auditor reports that were published by in-scope entities for the latest twelve-months period available as at the date of the research (mostly periods ended on 31 December 2017 and 31 March 2018). All values were denominated to euro (EUR) with use of average exchange rates published by the National Bank of Poland. All performed analyses and developed charts were supported by Microsoft Power BI data analysis tool. Findings: The general conclusion, which may be drawn from this research, is that implementation of ISA 701 and materiality disclosure limited the audit expectation gap. Detailed observations are described throughout the paper and summarized in the conclusions section. Originality/value: This study extends the prior research by providing various dimensions of the analysed matters. It contributes to understanding of the audit expectation gap and investigates on methods of minimizing it.
Cooled Pads for Tilting-Pad Journal Bearings
Authors: Chatterton Steven , Pennacchi Paolo , Vania Andrea , Dang Phuoc Vinh
Published: October 2019

Tilting-pad journal bearings (TPJBs) are widely installed in rotating machines owing to their high stability, but some drawbacks can be noted, such as higher cost with respect to cylindrical journal bearings and thermal issues. High temperatures in the pads correspond to low oil-film thicknesses and large thermal deformations in the pads. Therefore, the restriction of the maximum temperature of the bearing is a key aspect for oil-film bearings. The temperature reduction is generally obtained by adopting higher oil inlet flowrates or suitable oil nozzles. In this paper, the idea of using cooled pads with internal channels in which an external cooling fluid is circulated will be applied to a TPJB for the first time. The three-dimensional TEHD model of the TPJB, equipped with a cooled pad, will be introduced, and the results of the numerical simulations will be discussed. Several analyses have been performed in order to investigate the influence of cooling conditions, such as the type, flowrate, inlet temperature and number of cooled pads. Two types of pad geometry with different cross-sections of the cooling circuit, namely, circular and six-square multi-channel sections, have been compared to the reference bearing with solid pads. Simple experimental tests were performed by means of a test rig equipped with a cooled pad bearing obtained with the additive manufacturing process, thus showing the effectiveness of the solution and the agreement with the predictions.
Cubic Silver Nanoparticles Fixed on TiO2 Nanotubes as Simple and Efficient Substrates for Surface Enhanced Raman Scattering
Authors: Ambroziak Robert , Hołdyński Marcin , Płociński Tomasz , Pisarek Marcin , Kudelski Andrzej
Published: October 2019

In this work we show that ordered freestanding titanium oxide nanotubes (TiO2 NT) may be used as substrates for the simple and efficient immobilization of anisotropic plasmonic nanoparticles. This is important because anisotropic plasmonic nanostructures usually give greater spectral enhancement than spherical nanoparticles. The size of the pores in a layer of titanium oxide nanotubes can be easily fitted to the size of many silver plasmonic nanoparticles highly active in SERS (surface-enhanced Raman scattering) spectroscopy (for example, silver nanocubes with an edge length of ca. 45 nm), and hence, the plasmonic nanoparticles deposited can be strongly anchored in such a titanium oxide substrate. The tubular morphology of the TiO2 substrate used allows a specific arrangement of the silver plasmonic nanoparticles that may create many so-called SERS hot spots. The SERS activity of a layer of cubic Ag nanoparticles (AgCNPs) deposited on a tubular TiO2 substrate (AgCNPs@TiO2 NT) is about eight times higher than that of the standard electrochemically nanostructured surface of a silver electrode (produced by oxidation reduction cycling). Furthermore, a super hydrophilic character of the TiO2 nanotubes surface allows for a uniform distribution of AgCNPs, which are deposited from an aqueous suspension. The new AgCNPs@TiO2 NT hybrid layer ensures a good reproducibility of SERS measurements and exhibits a higher temporal stability of the achievable total SERS enhancement factor—one that is far better than standard SERS silver substrates. To characterize the morphology and chemical composition of such evidently improved SERS platforms thus received, we applied microscopic techniques (SEM, and scanning transmission electron microscopy (STEM)) and surface analytical techniques (Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS)).
FEM Simulation and Verification of Brazing SiC Ceramic with Novel Zr-Cu Filler Metal
Authors: Zhou Bofang , Zeng Zhichen , Cai Yuchen , Feng Keqin
Published: October 2019

Zr-Cu filler metal is proposed for SiC ceramic under special working conditions, as a novel type of the active filler metal, the difference of physical and chemical properties between SiC ceramic and Zr-Cu filler metal leads to greater residual stress in the joint, which affects the mechanical properties of brazing SiC ceramic joint. Based on the finite element method (FEM) simulation, the residual stress of the joint is simulated to guide the design of Zr-based filler metal and formulation of brazing process. The residual stress distribution of SiC ceramic joints brazed at 1200 °C with different thickness of the filler metal and cooling rate is simulated by ANSYS software. The simulation results of the residual stress are verified by brazing experiments and XRD measurements. The results show that the simulated residual stress of the joint is mainly axial compressive stress. The axial compressive stresses are the lowest when the filler metal thickness is 0.1 mm and the cooling rate is 2 °C /min, and increase with the increase of the filler metal layer thickness and cooling rate. The shear strength of the brazed SiC ceramic joint that achieves the highest with 2 °C /min is about 72 MPa, and then decreases with the increase of cooling rate. The experimental test of residual stress in different locations of the brazed SiC ceramic joint basically coincide with the FEM simulation.
Direct Pulp Capping: Which is the Most Effective Biomaterial? A Retrospective Clinical Study
Authors: Paula Anabela , Carrilho Eunice , Laranjo Mafalda , Abrantes Ana M. , Casalta-Lopes João , Botelho Maria Filomena , Marto Carlos Miguel , Ferreira Manuel M.
Published: October 2019

(1) Background: Recently, tricalcium silicate cements, such as Biodentine™, have emerged. This biomaterial has a calcium hydroxide base and characteristics like mineral aggregate trioxide cements, but has tightening times that are substantially more suitable for their application and other clinical advantages. (2) Methods: A retrospective clinical study was conducted with 20 patients, which included a clinical evaluation of the presence or absence of pulp inflammation compatible symptoms, radiographic evaluation of the periapical tissues, and structural alterations of the coronary restoration that supports pulp capping therapies with Biodentine™ and WhiteProRoot®MTA. (3) Results: This clinical study revealed similar success rates between mineral trioxide cement and tricalcium silicates cements at 6 months, with 100% and 95% success rates, respectively. There were no statistically significant differences between both biomaterials and between these and the various clinical circumstances, namely the absolute isolation of the operating field, exposure size, the aetiology of exposure, and even the type of restorative material used. (4) Conclusions: Biodentine™ demonstrated a therapeutic effect on the formation of a dentin bridge accompanied by slight inflammatory signs, with a high clinical success rate, indicating the possibility of its effective and safe use in dental pulp direct capping in humans, similar to the gold standard material.
Experimental Research and Analysis on Fatigue Life of Carbon Fiber Reinforced Polymer (CFRP) Tendons
Authors: Song Shoutan , Zang Hua , Duan Ning , Jiang Juntao
Published: October 2019

The fatigue life of carbon fiber reinforced polymer (CFRP) tendons was studied in this paper. A new wedge-type anchorage system was applied to the fatigue test of CFRP tendons and demonstrated an excellent fatigue resistance. In the test and analytical data, the fatigue stress ranged from 200 MPa to 800 MPa, and maximum stresses from 0.37 to 1.0 f u ( f u = ultimate tensile strength of CFRP tendons) were determined. The main work and results were that the stress range and stress level (maximum stress) were two key parameters affecting the fatigue life of CFRP tendons. A bilinear equation and a linear equation considering the fatigue life of CFRP tendons jointly affected by the stress range and the maximum stress were established. The error of predicted results and test results was 0.038 and 0.083, respectively, both representing good prediction accuracy. The predicted results of Whitney’s method showed that, at a 95% confidence level, when the stress range was 200 MPa, 400 MPa, and 600 MPa, the maximum stress limit of CFRP tendons, which were not broken in a fatigue test of 2 million times, was 63.9% f u , 53.0% f u , and 36.8% f u , respectively.
Dynamic Simulation of a Fe-Ga Energy Harvester Prototype Through a Preisach-Type Hysteresis Model
Authors: Palumbo Stefano , Chiampi Mario , Bottauscio Oriano , Zucca Mauro
Published: October 2019

This paper presents the modeling of an Fe–Ga energy harvester prototype, within a large range of values of operating parameters (mechanical preload, amplitude and frequency of dynamic load, electric load resistance). The simulations, based on a hysteretic Preisach-type model, employ a voltage-driven finite element formulation using the fixed-point technique, to handle the material nonlinearities. Due to the magneto–mechanical characteristics of Fe–Ga, a preliminary tuning must be performed for each preload to individualize the fixed point constant, to ensure a good convergence of the method. This paper demonstrates how this approach leads to good results for the Fe–Ga prototype. The relative discrepancies between experimental and computational values of the output power remain lower than 5% in the entire range of operating parameters considered.
An Active Absorbent for Cleanup of High-Concentration Strong Acid and Base Solutions
Authors: Han Nara , Park Sol , Kaang Byung Kwon , Jang Wooree , Koo Hye Young , Choi Won San
Published: October 2019

There is significant interest in developing novel absorbents for hazardous material cleanup. Iron oxide-coated melamine formaldehyde sponge (MFS/IO) absorbents with various IO layer thicknesses were synthesized. Various other absorbents were also synthesized and compared to evaluate the absorption capability of the MFS/IO absorbents for strong acid (15%, v/v) and base (50%, m/m) solutions. Specifically, absorbent and solution drop tests, dust tests, and droplet fragment tests were performed. Among the various absorbents, MFS/IO absorbents possessing a needlelike surface morphology showed several unique characteristics not observed in other absorbents. The MFS/IO absorbents naturally absorbed a strong base solution (absorption time: 0.71–0.5 s, absorption capacity: 10,000–34,000%) without an additional external force and immediately absorbed a strong acid solution (0.31–0.43 s, 9830–10,810%) without absorption delay/overflow during absorbent and solution drop tests, respectively. The MFS/IO absorbents were also demonstrated to be ideal absorbents that generated fewer dust particles (semiclass 1 (ISO 3) level of 280 piece/L) than the level of a clean room (class 100). Furthermore, the MFS/IO absorbents were able to prevent the formation of droplet fragments and solution overflow during the solution drop test due to their unique surface morphology and extremely high absorption speed/capacity, respectively.
A Finite Element Model for the Vibration Analysis of Sandwich Beam with Frequency-Dependent Viscoelastic Material Core
Authors: Huang Zhicheng , Wang Xingguo , Wu Nanxing , Chu Fulei , Luo Jing
Published: October 2019

In this work, a finite element model was developed for vibration analysis of sandwich beam with a viscoelastic material core sandwiched between two elastic layers. The frequency-dependent viscoelastic dynamics of the sandwich beam were investigated by using finite element analysis and experimental validation. The stiffness and damping of the viscoelastic material core is frequency-dependent, which results in complex vibration modes of the sandwich beam system. A third order seven parameter Biot model was used to describe the frequency-dependent viscoelastic behavior, which was then incorporated with the finite elements of the sandwich beam. Considering the parameters identification, a strategy to determine the parameters of the Biot model has been outlined, and the curve fitting results closely follow the experiment. With identified model parameters, numerical simulations were carried out to predict the vibration and damping behavior in the first three vibration modes, and the results showed that the finite model presented here had good accuracy and efficiency in the specific frequency range of interest. The experimental testing on the viscoelastic sandwich beam validated the numerical predication. The experimental results also showed that the finite element modeling method of sandwich beams that was proposed was correct, simple and effective.
Effect of Dentin Bonding Agents, Various Resin Composites and Curing Modes on Bond Strength to Human Dentin
Authors: Steiner Rene , Edelhoff Daniel , Stawarczyk Bogna , Dumfahrt Herbert , Lente Isabel
Published: October 2019

This study investigated the influence of several dentin bonding agents, resin composites and curing modes on push-out bond strength to human dentin. 360 extracted caries-free third molars were prepared, cut into slices, embedded in epoxy resin and perforated centrally. One half of the specimens (180) were treated by using one-step adhesive systems and the other half (180) with multi-step adhesive systems. Subsequently, the cavities were filled with either universal, flowable or bulk-fill resin composite according to the manufactures’ product line and cured with either turbo or soft start program. After storage the push-out test was performed. The data was analyzed using Kolmogorov-Smirnov, three- and one-way ANOVA followed by the Scheffé post-hoc test, unpaired two-sample t-test (p < 0.05). The strongest influence on push-out bond strength was exerted by the resin composite type (partial eta squared ηP2 = 0.505, p < 0.001), followed by the adhesive system (ηP2 = 0.138, p < 0.001), while the choice of the curing intensity was not significant (p = 0.465). The effect of the binary or ternary combinations of the three parameters was significant for the combinations resin composite type coupled adhesive system (ηP2 = 0.054, p < 0.001), only. The flowable resin composites showed predominantly mixed, while the universal and bulk-fill resin composite showed adhesive failure types. Cohesive failure types were not observed in any group. Multi-step adhesive systems are preferable to one-step adhesive systems due to their higher bond strength to dentin. Flowable resin composites showed the highest bond strength and should become more important as restoration material especially in cavity lining. The use of a soft start modus for polymerization of resin composites does not enhance the bond strength to dentin.
Antibacterial Activity and Biodegradation of Cellulose Fiber Blends with Incorporated ZnO
Authors: Malis Domen , Jeršek Barbka , Tomšič Brigita , Štular Danaja , Golja Barbara , Kapun Gregor , Simončič Barbara
Published: October 2019

This research aimed to study the influence of lyocell with incorporated ZnO (CLY) for antibacterial activity and biodegradation of fiber blends composed of viscose (CV), flax (LI), and CLY. Fiber blended samples with an increased weight fraction of CLY fibers were composed, and single CLY, CV and LI fibers were also used for comparison. Antibacterial activity was determined for the Gram-negative Escherichia coli and the Gram-positive Staphylococcus aureus bacteria. The biodegradation of fiber blends was investigated by the soil burial test. The results show that the single CLY fibers exhibited high antimicrobial activity against both E. coli and S. aureus bacteria and that the presence of LI fibers in the blended samples did not significantly affect antibacterial activity against E. coli, but drastically decreased the antibacterial activity against S. aureus. LI fibers strongly promoted the growth of S. aureus and, consequently, impaired the antimicrobial performance of ZnO against this bacterium. The presence of CLY fibers slowed down, but did not prevent, the biodegradation process of the fiber blends, even at the highest ZnO concentration. The soil that was in contact with the fiber blended samples during their burial was not contaminated to such an extent as to affect the growth of sprouts, confirming the sustainability of the fiber blends.
Three-Dimensional Vibration Analysis of a Functionally Graded Sandwich Rectangular Plate Resting on an Elastic Foundation Using a Semi-Analytical Method
Authors: Cui Jie , Zhou Taoran , Ye Renchuan , Gaidai Oleg , Li Zichao , Tao Shenghui
Published: October 2019

The three-dimensional vibration of a functionally graded sandwich rectangular plate on an elastic foundation with normal boundary conditions was analyzed using a semi-analytical method based on three-dimensional elasticity theory. The material properties of the sandwich plate varied with thickness according to the power law distribution. Two types of functionally graded material (FGM) sandwich plates were investigated in this paper: one with a homogeneous core and FGM facesheets, and another with homogeneous panels and an FGM core. Various displacements of the plates were created using an improved Fourier series consisting of a standard Fourier cosine series along with a certain number of closed-form auxiliary functions satisfying the essential boundary conditions. The vibration behavior of the FGM sandwich plate, including the natural frequencies and mode shapes, was obtained using the Ritz method. The effectiveness and accuracy of the suggested technique were fully verified by comparing the natural frequencies of sandwich plates with results from investigations of other functionally graded sandwich rectangular plates in the literature. A parametric study, including elastic parameters, foundation parameters, power law exponents, and layer thickness ratios, was performed, and some new results are presented.
Meso-Scale Simulation of Concrete Uniaxial Behavior Based on Numerical Modeling of CT Images
Authors: Sun Haokai , Gao Yang , Zheng Xinyu , Chen Yibo , Jiang Zhen , Zhang Zeyao
Published: October 2019

It is important to study the failure mechanism of concrete by observing the crack expansion and capturing key structures at the mesoscale. This manuscript proposed a method for efficiently identifying aggregate boundary information by X-ray computed tomography technology (CT) and a discrete element modeling method (DEM) for equivalent random polygon aggregates. This method overcomes the shortcomings of the Grain Based Model (GBM) which is impossible to establish a mesoscopic model with a large difference in grain radius. Through the above two methods, the CT slice images were processed in batches, and the numbers of edges, axial length, elongation of the aggregate were identified. The feasibility of the method was verified by the comparison between experimental and simulating results. Three mesoscopic models for different porosities were established. Based on aggregate statistics, this manuscript achieved the meso-model recovery to the maximum extent. The test results show that the crack appeared at the tip of the aggregate firstly, and then the broken boundary was applied in the direction of the applied load and around the pores. Finally, the crack was selectively expanded under the axial force. During the loading process, the minor principal stress was normally distributed. As the porosity and loading time increased, the heterogeneity increased.
An Investigation of the Common Solutions for Coupled Systems of Functional Equations Arising in Dynamic Programming
Authors: Işık Hüseyin , Sintunavarat Wutiphol
Published: October 2019

The purpose of this paper is to introduce the new notion of a specific point in the space of the bounded real-valued functions on a given non-empty set and present a result based on the existence and uniqueness of such points. As a consequence of our results, we discuss the existence of a unique common solution to coupled systems of functional equations arising in dynamic programming.