bluuebunny/crossref_metadata_2025 huggingface dataset:
A Feed-Forward Neural Network Approach for Energy-Based Acoustic Source Localization
Authors: Correia Sérgio D. , Tomic Slavisa , Beko Marko
Published: April 2021

The localization of an acoustic source has attracted much attention in the scientific community, having been applied in several different real-life applications. At the same time, the use of neural networks in the acoustic source localization problem is not common; hence, this work aims to show their potential use for this field of application. As such, the present work proposes a deep feed-forward neural network for solving the acoustic source localization problem based on energy measurements. Several network typologies are trained with ideal noise-free conditions, which simplifies the usual heavy training process where a low mean squared error is obtained. The networks are implemented, simulated, and compared with conventional algorithms, namely, deterministic and metaheuristic methods, and our results indicate improved performance when noise is added to the measurements. Therefore, the current developed scheme opens up a new horizon for energy-based acoustic localization, a field where machine learning algorithms have not been applied in the past.
The Effect of Temperature and Sputtered Particles on the Wettability of Al/Al2O3
Authors: Li Yang , Shang Hailong , Ma Bingyang , Guo Xuqiang , Li Rongbin , Li Geyang
Published: April 2021

Two kinds of Al2O3 ceramic samples with and without Al film deposited were designed respectively. The influences of temperature and high kinetic energy sputtering particles on the wettability and interface strength of Al/Al2O3 were studied by comparing the wetting behavior of molten aluminum on two samples. The results show that molten aluminum does not wet the Al2O3 sample without Al film deposited at 700 °C, the contact angle is 165°, and the interfacial shear strength is 28 MPa. With the increase of temperature, the contact angle decreases continuously, and the interface shear strength gradually increases. The fracture of the brazed joint is transferred from the interface to the brazing seam. In comparison, the sample deposited with Al film is wetted by molten aluminum at 700 °C, and the contact angle is only 12°. The interface shear strength is about 120 MPa and is less affected by temperature. The shear fracture of the joint occurs in the brazed seam of Al metal. Therefore, the high energy generated by either the temperature increase or the particle sputtering enable the Al atoms to overcome the energy barrier to form Al–O bonds with the O atoms on the Al2O3 ceramic surface, thereby improving the wettability of Al/Al2O3.
Preliminary In Vitro Wear Assessment of Ceramic Cemented Femoral Components Coupled with Polyethylene Menisci
Authors: Affatato Saverio , Erani Paolo , Fersini Maurizio , Contaldi Vincenzo , Terrizzi Anna Rita , Licciulli Antonio
Published: April 2021

Success of total knee replacement (TKR) depends on the prosthetic design and materials. The use of metal components is well established with the disadvantage of allergic reactions. Ceramics have been recently proposed because of high wear resistance, excellent biocompatibility, wettability, and suitable mechanical properties. This study was aimed at investigating in vitro wear resistance of Zirconia Toughened Alumina (ZTA)/Ultra-high-molecular-weight polyethylene (UHMWPE) of TKR femoral components. An in vitro protocol was designed with the application of relevant load profile, 6-degrees-of-freedom knee simulator, and 8 × 105 cycles on the ZTA/UHMWPE configuration under bovine calf serum. Before and after wear test, the femoral components were investigated by using the Scanning Electron Microscope (SEM) and the X-Ray Diffraction (XRD) analyses, and stylus surface roughness measurements. The proposed pre-clinical test yielded repeatable results. In particular, gravimetric results showed that, after 8 × 105 cycles, the mean weight loss of the polyethylene mobile components is 5.3 ± 1.1 mg. The surface roughness measurements (Ramax) performed after the wear test showed no significant variation on the UHMWPE menisci. A slight increase of roughness has been found on the ZTA (0.02 µm before wear test, 0.28 µm after the test). SEM observations did not show significant modification of the surface morphology. Tetragonal to monoclinic phase ratio was measured by XRD before and after wear test to evaluate stability of tetragonal ZrO2 phase. Minimal conversion of tetragonal to monoclinic phase was found from 5.4 to 8%. Although this study is a preliminary evaluation limited to in vitro tests, it provides novel pre-clinical indications about the potential of ceramic TKR femoral components.
Tensile Damage Study of Wind Turbine Tower Material Q345 Based on an Acoustic Emission Method
Authors: Tang Xiao , Liao Lida , Huang Bin , Li Cong
Published: April 2021

As essential load-bearing equipment to support the nacelle and blades, the tower is subjected to the whole wind turbine loading. This study proposes a new method of combining acoustic emission and normalized accumulation parameters to characterize wind turbine towers Q345 steel damage. First of all, tendency analysis of the acoustic emission signal parameter was conducted to determine damage degree during the damage stage. Secondly, we normalized the accumulation of amplitude and other parameters to compare the proportion of each accumulation parameter at different stages, while studying the spectra of common acoustic emission signals. Finally, comparing the differences and similarities of the normalized accumulation parameters between three different rates, we analyze the effect of rate on the normalized accumulation parameters. These results indicate that the normalized cumulative duration parameter is suitable for characterizing the yield damage occurrence, the normalized cumulative energy parameter is very sensitive to the fracture stage, the normalized cumulative energy parameter is least influenced by the loading rate, and the energy parameter is a sensitivity factor for normalized expression, which to realizes the stage of damage judgment.
Use of Cement Suspension as an Alternative Matrix Material for Textile-Reinforced Concrete
Authors: Fürst Richard , Fürst Eliška , Vlach Tomáš , Řepka Jakub , Pokorný Marek , Mózer Vladimír
Published: April 2021

Textile-reinforced concrete (TRC) is a material consisting of high-performance concrete (HPC) and tensile reinforcement comprised of carbon roving with epoxy resin matrix. However, the problem of low epoxy resin resistance at higher temperatures persists. In this work, an alternative to the epoxy resin matrix, a non-combustible cement suspension (cement milk) which has proven stability at elevated temperatures, was evaluated. In the first part of the work, microscopic research was carried out to determine the distribution of particle sizes in the cement suspension. Subsequently, five series of plate samples differing in the type of cement and the method of textile reinforcement saturation were designed and prepared. Mechanical experiments (four-point bending tests) were carried out to verify the properties of each sample type. It was found that the highest efficiency of carbon roving saturation was achieved by using finer ground cement (CEM 52.5) and the pressure saturation method. Moreover, this solution also exhibited the best results in the four-point bending test. Finally, the use of CEM 52.5 in the cement matrix appears to be a feasible variant for TRC constructions that could overcome problems with its low temperature resistance.
Application of the Generalized Bochner Technique to the Study of Conformally Flat Riemannian Manifolds
Authors: Mikeš Josef , Rovenski Vladimir , Stepanov Sergey , Tsyganok Irina
Published: April 2021

In this article, we discuss the global aspects of the geometry of locally conformally flat (complete and compact) Riemannian manifolds. In particular, the article reviews and improves some results (e.g., the conditions of compactness and degeneration into spherical or flat space forms) on the geometry “in the large" of locally conformally flat Riemannian manifolds. The results presented here were obtained using the generalized and classical Bochner technique, as well as the Ricci flow.
Microscopic Numerical Simulations of Epidemic Models on Networks
Authors: Okabe Yutaka , Shudo Akira
Published: April 2021

Mathematical models of the spread of epidemic diseases are studied, paying special attention to networks. We treat the Susceptible-Infected-Recovered (SIR) model and the Susceptible-Exposed-Infectious-Recovered (SEIR) model described by differential equations. We perform microscopic numerical simulations for corresponding epidemic models on networks. Comparing a random network and a scale-free network for the spread of the infection, we emphasize the role of hubs in a scale-free network. We also present a simple derivation of the exact solution of the SIR model.
An Interactive Recommendation System for Decision Making Based on the Characterization of Cognitive Tasks
Authors: Macias-Escobar Teodoro , Cruz-Reyes Laura , Medina-Trejo César , Gómez-Santillán Claudia , Rangel-Valdez Nelson , Fraire-Huacuja Héctor
Published: April 2021

The decision-making process can be complex and underestimated, where mismanagement could lead to poor results and excessive spending. This situation appears in highly complex multi-criteria problems such as the project portfolio selection (PPS) problem. Therefore, a recommender system becomes crucial to guide the solution search process. To our knowledge, most recommender systems that use argumentation theory are not proposed for multi-criteria optimization problems. Besides, most of the current recommender systems focused on PPS problems do not attempt to justify their recommendations. This work studies the characterization of cognitive tasks involved in the decision-aiding process to propose a framework for the Decision Aid Interactive Recommender System (DAIRS). The proposed system focuses on a user-system interaction that guides the search towards the best solution considering a decision-maker’s preferences. The developed framework uses argumentation theory supported by argumentation schemes, dialogue games, proof standards, and two state transition diagrams (STD) to generate and explain its recommendations to the user. This work presents a prototype of DAIRS to evaluate the user experience on multiple real-life case simulations through a usability measurement. The prototype and both STDs received a satisfying score and mostly overall acceptance by the test users.
Modulatory Effects of Acidic pH and Membrane Potential on the Adsorption of pH-Sensitive Peptides to Anionic Lipid Membrane
Authors: Alvares Dayane dos Santos , Martins Ingrid Bernardes Santana , Viegas Taisa Giordano , Palma Mario Sergio , de Araujo Alexandre Suman , de Carvalho Sidney Jurado , Ruggiero Neto João
Published: April 2021

Anionic lipid membrane electrostatic potential and solution pH can influence cationic peptide adsorption to these bilayers, especially those containing simultaneously acid and basic residues. Here, we investigate the effects of the pH solution on MP1 (IDWKKLLDAAKQIL-NH2) adsorption to anionic (7POPC:3POPG) lipid vesicles in comparison to its analog H-MP1, with histidines substituting lysines. We used the association of adsorption isotherms and constant pH molecular dynamic simulations (CpHMD) to explore the effects of membrane potential and pH on peptides’ adsorption on this lipid membrane. We analyzed the fluorescence and zeta potential adsorption isotherms using the Gouy–Chapman theory. In CpHMD simulations for the peptides in solution and adsorbed on the lipid bilayer, we used the conformations obtained by conventional MD simulations at a μs timescale. Non-equilibrium Monte Carlo simulations provided the protonation states of acidic and basic residues. CpHMD showed average pKa shifts of two to three units, resulting in a higher net charge for the analog than for MP1, strongly modulating the peptide adsorption. The fractions of the protonation of acidic and basic residues and the peptides’ net charges obtained from the analysis of the adsorption isotherms were in reasonable agreement with those from CpHMD. MP1 adsorption was almost insensitive to solution pH. H-MP1 was much more sensitive to partitioning, at acidic pH, with an affinity ten times higher than in neutral ones.
Butyrate Prevents TGF-β1-Induced Alveolar Myofibroblast Differentiation and Modulates Energy Metabolism
Authors: Lee Hyo Yeong , Nam Somi , Kim Mi Jeong , Kim Su Jung , Back Sung Hoon , Yoo Hyun Ju
Published: April 2021

Idiopathic pulmonary fibrosis (IPF) is a serious lung disease characterized by excessive collagen matrix deposition and extracellular remodeling. Signaling pathways mediated by fibrotic cytokine transforming growth factor β1 (TGF-β1) make important contributions to pulmonary fibrosis, but it remains unclear how TGF-β1 alters metabolism and modulates the activation and differentiation of pulmonary fibroblasts. We found that TGF-β1 lowers NADH and NADH/NAD levels, possibly due to changes in the TCA cycle, resulting in reductions in the ATP level and oxidative phosphorylation in pulmonary fibroblasts. In addition, we showed that butyrate (C4), a short chain fatty acid (SCFA), exhibits potent antifibrotic activity by inhibiting expression of fibrosis markers. Butyrate treatment inhibited mitochondrial elongation in TGF-β1-treated lung fibroblasts and increased the mitochondrial membrane potential (MMP). Consistent with the mitochondrial observations, butyrate significantly increased ADP, ATP, NADH, and NADH/NAD levels in TGF-β1-treated pulmonary fibroblasts. Collectively, our findings indicate that TGF-β1 induces changes in mitochondrial dynamics and energy metabolism during myofibroblast differentiation, and that these changes can be modulated by butyrate, which enhances mitochondrial function.
Impact of High-Pressure Processed Onion on Colonic Metabolism Using a Dynamic Gastrointestinal Digestion Simulator
Authors: Fernández-Jalao Irene , Balderas Claudia , Calvo María V. , Fontecha Javier , Sánchez-Moreno Concepción , De Ancos Begoña
Published: April 2021

Onions are the main dietary source of flavonols that have been associated with important health-promoting properties. Onion treated by high-pressure processing (HPP-treated onion) was subjected to a dynamic gastrointestinal digestion and colon fermentation simulator (DGID-CF) to study the effect on the gut microbiota metabolism in the three colon regions (ascending—AC, transverse—TC, and descending—DC) by means of chronic feeding with 27 g/day for 14 days. HPP-treated onion presented a high content of the flavonols quercetin-3,4’-diglucoside and quercetin-4’-glucoside, and a large percentage of them reached the AC without change. TC and DC progressively increased the total phenolic metabolites 2.5 times respective to day 2, mainly 3-hydroxyphenylacetic, 4-hydroxyphenylacetic, 3-(4-hydroxyphenyl)-propionic, and 3,4-dihydroxyphenylpropionic acids. In addition, the chronic feeding increased the beneficial colon bacteria Bifidobacterium spp. and Lactobacillus spp. and the production of total SCFAs (acetic, propionic, and butyric acids) 9 times (AC), 2.2 times (TC), and 4.4 times (DC) respective to day 1. A multivariate analysis (principal component analysis, PCA) showed a clear separation between the three colon regions based on their phenolic composition (precursors and metabolites). These results showed that HPP-treated onion modulated the human gut microbiota’s metabolism and the DGID-CF is a good system to study these changes.
Uncertainty Evaluation on a 10.52 GHz (5 dBm) Optoelectronic Oscillator Phase Noise Performance
Authors: Salzenstein Patrice , Pavlyuchenko Ekaterina
Published: April 2021

This paper describes a prototype of an optoelectronic oscillator delivering a microwave signal with a power of 5 dBm at 10.52 GHz, promised to be compacted. It is evaluated in terms of its phase noise performance, and the associated ±2 dB uncertainty at 2 σ is calculated according to the international standards enacted for metrology.
Micro-Actuated Tunable Hierarchical Silver Nanostructures to Measure Tensile Force for Biomedical Wearable Sensing Applications
Authors: Kwon Yong Ho , Fernandes Jayer , Kim Jae-Jun , Chen Jiangang , Jiang Hongrui
Published: April 2021

Commercially available biomedical wearable sensors to measure tensile force/strain still struggle with miniaturization in terms of weight, size, and conformability. Flexible and epidermal electronic devices have been utilized in these applications to overcome these issues. However, current sensors still require a power supply and some form of powered data transfer, which present challenges to miniaturization and to applications. Here, we report on the development of flexible, passive (thus zero power consumption), and biocompatible nanostructured photonic devices that can measure tensile strain in real time by providing an optical readout instead of an electronic readout. Hierarchical silver (Ag) nanostructures in various thicknesses of 20–60 nm were fabricated and embedded on a stretchable substrate using e-beam lithography and a low-temperature dewetting process. The hierarchical Ag nanostructures offer more design flexibility through a two-level design approach. A tensional force applied in one lateral (x- or y-) direction of the stretchable substrate causes a Poisson contraction in the other, and as a result, a shift in the reflected light of the nanostructures. A clear blue shift of more than 100 nm in peak reflectance in the visible spectrum was observed in the reflected color, making the devices applicable in a variety of biomedical photonic sensing applications.
Numerical Investigation of T-Shaped Microfluidic Oscillator with Viscoelastic Fluid
Authors: Yuan Chao , Zhang Hongna , Li Xiaobin , Oishi Masamichi , Oshima Marie , Yao Qinghe , Li Fengchen
Published: April 2021

Oscillatory flow has many applications in micro-scaled devices. The methods of realizing microfluidic oscillators reported so far are typically based on the impinging-jet and Coanda effect, which usually require the flow Reynolds number to be at least at the order of unity. Another approach is to introduce elastomeric membrane into the microfluidic units; however, the manufacturing process is relatively complex, and the membrane will become soft after long-time operation, which leads to deviation from the design condition. From the perspective of the core requirement of a microfluidic circuit, i.e., nonlinearity, the oscillatory microfluidic flow can be realized via the nonlinear characteristics of viscoelastic fluid flow. In this paper, the flow characteristics of viscoelastic fluid (Boger-type) in a T-shaped channel and its modified structures are studied by two-dimensional direct numerical simulation (DNS). The main results obtained from the DNS study are as follows: (1) Both Weissenberg (Wi) number and viscosity ratio need to be within a certain range to achieve a periodic oscillating performance; (2) With the presence of the dynamic evolution of the pair of vortices in the upstream near the intersection, the oscillation intensity increases as the elasticity-dominated area in the junction enlarges; (3) Considering the simplicity of the T-type channel as a potential oscillator, the improved structure should have a groove carved toward the entrance near the upper wall. The maximum oscillation intensity measured by the standard deviation of flow rate at outlet is increased by 129% compared with that of the original standard T-shaped channel under the same condition. To sum up, with Wi number and viscosity ratio within a certain range, the regular periodic oscillation characteristics of Oldroyd-B type viscoelastic fluid flow in standard T-shaped and its modified channels can be obtained. This structure can serve as a passive microfluidic oscillator with great potential value at an extremely low Reynolds number, which has the advantages of simplicity, no moving parts and fan-out of two.
New Possibilities for Testing the Service Life of Magnetic Contacts
Authors: Boroš Martin , Veľas Andrej , Zvaková Zuzana , Šoltés Viktor
Published: April 2021

Magnetic contacts we could define as a switching device used in transport structures such as a tunnel, to which the manufacturer prescribes a certain number of closures within its lifetime, during which they should operate flawlessly. Verification of the data provided by the manufacturer is time-consuming and physically demanding due to the data being large in number. For this reason, we developed a test device using torque in the research of magnetic contacts, which greatly automates the whole process and thus eliminates human error. The test device can use internal memory to calculate the number of closures of magnetic contacts and then transmit the digitized data. The test device is registered as an industrial utility model and can be used to test any magnetic contacts.
Bovine Milk Oligosaccharides and Human Milk Oligosaccharides Modulate the Gut Microbiota Composition and Volatile Fatty Acid Concentrations in a Preclinical Neonatal Model
Authors: Wang Mei , Monaco Marcia H. , Hauser Jonas , Yan Jian , Dilger Ryan N. , Donovan Sharon M.
Published: April 2021

Milk oligosaccharides (OS) shape microbiome structure and function, but their relative abundances differ between species. Herein, the impact of the human milk oligosaccharides (HMO) (2′-fucosyllactose [2′FL] and lacto-N-neotetraose [LNnT]) and OS isolated from bovine milk (BMOS) on microbiota composition and volatile fatty acid (VFA) concentrations in ascending colon (AC) contents and feces was assessed. Intact male piglets received diets either containing 6.5 g/L BMOS (n = 12), 1.0 g/L 2′FL + 0.5 g/L LNnT (HMO; n = 12), both (HMO + BMOS; n = 10), or neither (CON; n = 10) from postnatal day (PND) 2 to 34. Microbiota were assessed by 16S rRNA gene sequencing and real-time PCR, and VFA were measured by gas chromatography. The microbiota was affected by OS in an intestine region-specific manner. BMOS reduced (p < 0.05) microbial richness in the AC, microbiota composition in the AC and feces, and acetate concentrations in AC, regardless of HMO presence. HMO alone did not affect overall microbial composition, but increased (p < 0.05) the relative proportion of specific taxa, including Blautia, compared to other groups. Bacteroides abundance was increased (p < 0.05) in the AC by BMOS and synergistically by BMOS + HMO in the feces. Distinct effects of HMO and BMOS suggest complementary and sometimes synergistic benefits of supplementing a complex mixture of OS to formula.
Pathogenic Role of Immune Evasion and Integration of Human Papillomavirus in Oropharyngeal Cancer
Authors: Hatano Takashi , Sano Daisuke , Takahashi Hideaki , Oridate Nobuhiko
Published: April 2021

The incidence of oropharyngeal cancer (OPC) is increasing remarkably among all head and neck cancers, mainly due to its association with the human papillomavirus (HPV). Most HPVs are eliminated by the host’s immune system; however, because HPV has developed an effective immune evasion mechanism to complete its replication cycle, a small number of HPVs are not eliminated, leading to persistent infection. Moreover, during the oncogenic process, the extrachromosomal HPV genome often becomes integrated into the host genome. Integration involves the induction and high expression of E6 and E7, leading to cell cycle activation and increased genomic instability in the host. Therefore, integration is an important event in oncogenesis, although the associated mechanism remains unclear, especially in HPV-OPC. In this review, we summarize the current knowledge on HPV-mediated carcinogenesis, with special emphasis on immune evasion and integration mechanisms, which are crucial for oncogenesis.
Novel Siphoviridae Bacteriophages Infecting Bacteroides uniformis Contain Diversity Generating Retroelement
Authors: Hedžet Stina , Rupnik Maja , Accetto Tomaž
Published: April 2021

Intestinal phages are abundant and important components of gut microbiota, yet the isolated and characterized representatives that infect abundant gut bacteria are sparse. Here we describe the isolation of human intestinal phages infecting Bacteroidesuniformis. Bacteroides is one of the most common bacterial groups in the global human gut microbiota; however, to date not many Bacteroides specific phages are known. Phages isolated in this study belong to a novel viral genus, Bacuni, within the Siphoviridae family. Their genomes encode diversity-generating retroelements (DGR), which were shown in other bacteriophages to promote phage adaptation to rapidly changing environmental conditions and to broaden their host range. Three isolated phages showed 99.83% genome identity but one of them infected a distinct B. uniformis strain. The tropism of Bacuni phages appeared to be dependent on the interplay of DGR mediated sequence variations of gene encoding putative phage fimbrial tip proteins and mutations in host genes coding for outer-membrane proteins. We found prophages with up to 85% amino acid similarity over two-thirds of the Bacuni phage genome in the B. acidifaciens and Prevotella sp. genomes. Despite the abundance of Bacteroides within the human microbiome, we found Bacuni phages only in a limited subset of published gut metagenomes.
Bugs That Can Resist Antibiotics but Not Men: Gender-Specific Differences in Notified Infections and Colonisations in Germany, 2010–2019
Authors: Brandl Michael , Hoffmann Alexandra , Willrich Niklas , Reuss Annicka , Reichert Felix , Walter Jan , Eckmanns Tim , Haller Sebastian
Published: April 2021

Data from surveillance networks show that men have a higher incidence rate of infections with anti-microbial-resistant (AMR) pathogens than women. We systematically analysed data of infections and colonisations with AMR pathogens under mandatory surveillance in Germany to quantify gender-specific differences. We calculated incidence-rates (IR) per 100,000 person–years for invasive infections with Methicillin-resistant Staphylococcus aureus (MRSA), and for infections or colonisations with carbapenem-non-susceptible Acinetobacter spp. (CRA), and Enterobacterales (CRE), using the entire German population as a denominator. We limited the study periods to years with complete notification data (MRSA: 2010–2019, CRA/CRE: 2017–2019). We used Poisson regression to adjust for gender, age group, federal state, and year of notification. In the study periods, IR for all notifications were 4.2 for MRSA, 0.90 for CRA, and 4.8 for CRE per 100,000 person-–years. The adjusted IR ratio for infections of men compared to women was 2.3 (95% confidence interval [CI]: 2.2–2.3) for MRSA, 2.2 (95%CI: 1.9–2.7) for CRA, and 1.7 (95%CI: 1.6–1.8) for CRE. Men in Germany show about double the risk for infection with AMR pathogens than women. This was also true for colonisations, where data were available. Screening procedures and associated hygiene measures may profit from a gender-stratified approach.
Food Waste-Assisted Metal Extraction from Printed Circuit Boards: The Aspergillus niger Route
Authors: Alias Carlotta , Bulgari Daniela , Bilo Fabjola , Borgese Laura , Gianoncelli Alessandra , Ribaudo Giovanni , Gobbi Emanuela , Alessandri Ivano
Published: April 2021

A low-energy paradigm was adopted for sustainable, affordable, and effective urban waste valorization. Here a new, eco-designed, solid-state fermentation process is presented to obtain some useful bio-products by recycling of different wastes. Urban food waste and scraps from trimmings were used as a substrate for the production of citric acid (CA) by solid state fermentation of Aspergillus niger NRRL 334, with a yield of 20.50 mg of CA per gram of substrate. The acid solution was used to extract metals from waste printed circuit boards (WPCBs), one of the most common electronic waste. The leaching activity of the biological solution is comparable to a commercial CA one. Sn and Fe were the most leached metals (404.09 and 67.99 mg/L, respectively), followed by Ni and Zn (4.55 and 1.92 mg/L) without any pre-treatments as usually performed. Commercial CA extracted Fe more efficiently than the organic one (123.46 vs. 67.99 mg/L); vice versa, biological organic CA recovered Ni better than commercial CA (4.55 vs. 1.54 mg/L). This is the first approach that allows the extraction of metals from WPCBs through CA produced by A. niger directly grown on waste material without any sugar supplement. This “green” process could be an alternative for the recovery of valuable metals such as Fe, Pb, and Ni from electronic waste.
The Microbiome of the Reef Macroalga Sargassum ilicifolium in Singapore
Authors: Oh Ren Min , Bollati Elena , Maithani Prasha , Huang Danwei , Wainwright Benjamin J.
Published: April 2021

The large canopy-forming macroalga, Sargassum ilicifolium, provides shelter and food for numerous coral reef species, but it can also be detrimental at high abundances where it outcompetes other benthic organisms for light and space. Here, we investigate the microbial communities associated with S. ilicifolium in Singapore, where it is an abundant and important member of coral reef communities. We collected eight complete S. ilicifolium thalli from eight island locations along an approximate 14 km east-to-west transect. Each thallus was dissected into three separate parts: holdfast, vesicles, and leaves. We then characterized the bacterial communities associated with each part via polymerase chain reaction (PCR) amplification of the 16S rRNA gene V4 region. We then inferred predicted metagenome functions using METAGENassist. Despite the comparatively short distances between sample sites, we show significant differences in microbial community composition, with communities further differentiated by part sampled. Holdfast, vesicles and leaves all harbor distinct microbial communities. Functional predictions reveal some separation between holdfast and leaf communities, with higher representation of sulphur cycling taxa in the holdfast and higher representation of nitrogen cycling taxa in the leaves. This study provides valuable baseline data that can be used to monitor microbial change, and helps lay the foundation upon which we can begin to understand the complexities of reef-associated microbial communities and the roles they play in the functioning and diversity of marine ecosystems.
The Impact and Burden of Neurological Sequelae Following Bacterial Meningitis: A Narrative Review
Authors: Schiess Nicoline , Groce Nora E. , Dua Tarun
Published: April 2021

The burden, impact, and social and economic costs of neurological sequelae following meningitis can be devastating to patients, families and communities. An acute inflammation of the brain and spinal cord, meningitis results in high mortality rates, with over 2.5 million new cases of bacterial meningitis and over 236,000 deaths worldwide in 2019 alone. Up to 30% of survivors have some type of neurological or neuro-behavioural sequelae. These include seizures, hearing and vision loss, cognitive impairment, neuromotor disability and memory or behaviour changes. Few studies have documented the long-term (greater than five years) consequences or have parsed out whether the age at time of meningitis contributes to poor outcome. Knowledge of the socioeconomic impact and demand for medical follow-up services among these patients and their caregivers is also lacking, especially in low- and middle-income countries (LMICs). Within resource-limited settings, the costs incurred by patients and their families can be very high. This review summarises the available evidence to better understand the impact and burden of the neurological sequelae and disabling consequences of bacterial meningitis, with particular focus on identifying existing gaps in LMICs.
The Potential for Natural Stones from Northeastern Brazil to Be Used in Civil Construction
Authors: Costa Fabiana Pereira da , Fernandes Jucielle Veras , Melo Luiz Ronaldo Lisboa de , Rodrigues Alisson Mendes , Menezes Romualdo Rodrigues , Neves Gelmires de Araújo
Published: April 2021

Natural stones (limestones, granites, and marble) from mines located in northeastern Brazil were investigated to discover their potential for use in civil construction. The natural stones were characterized by chemical analysis, X-ray diffraction, differential thermal analysis, and optical microscopy. The physical-mechanical properties (apparent density, porosity, water absorption, compressive and flexural strength, impact, and abrasion) and chemical resistance properties were also evaluated. The results of the physical-mechanical analysis indicated that the natural stones investigated have the potential to be used in different environments (interior, exterior), taking into account factors such as people’s circulation and exposure to chemical agents.
Iron Isotope Fractionation during Skarn Cu-Fe Mineralization
Authors: Xue Song , Niu Yaoling , Chen Yanhong , Shi Yining , Xia Boyang , Wang Peiyao , Gong Hongmei , Wang Xiaohong , Duan Meng
Published: April 2021

Fe isotopes have been applied to the petrogenesis of ore deposits. However, the behavior of iron isotopes in the mineralization of porphyry-skarn deposits is still poorly understood. In this study, we report the Fe isotopes of ore mineral separations (magnetite, pyrite, chalcopyrite and pyrrhotite) from two different skarn deposits, i.e., the Tonglvshan Cu-Fe skarn deposit developed in an oxidized hydrothermal system and the Anqing Cu skarn deposit developed in a reduced hydrothermal system. In both deposits, the Fe isotopes of calculated equilibrium fluids are lighter than those of the intrusions responsible for the skarn and porphyry mineralization, corroborating the “light-Fe fluid” hypothesis. Interestingly, chalcopyrite in the oxidized-Tonglvshan skarn deposit has lighter Fe than chalcopyrite in the reduced-Anqing skarn deposit, which is best understood as the result of the prior precipitation of magnetite (heavy Fe) from the ore fluid in the oxidized-Tonglvshan systems and the prior precipitation of pyrrhotite (light Fe) from the ore fluid in the reduced-Anqing system. The δ56Fe for pyrite shows an inverse correlation with δ56Fe of magnetite in the Tonglvshan. In both deposits, the Fe isotope fractionation between chalcopyrite and pyrite is offset from the equilibrium line at 350 °C and lies between the FeS-chalcopyrite equilibrium line and pyrite-chalcopyrite equilibrium line at 350 °C. These observations are consistent with the FeS pathway towards pyrite formation. That is, Fe isotopes fractionation during pyrite formation depends on a path from the initial FeS-fluid equilibrium towards the pyrite-fluid equilibrium due to the increasing extent of Fe isotopic exchange with fluids. This finding, together with the data from other deposits, allows us to propose that the pathway effect of pyrite formation in the Porphyry-skarn deposit mineralization is the dominant mechanism that controls Fe isotope characteristics.
Withaferin A—A Promising Phytochemical Compound with Multiple Results in Dermatological Diseases
Authors: Bungau Simona , Vesa Cosmin Mihai , Abid Areha , Behl Tapan , Tit Delia Mirela , Purza Anamaria Lavinia , Pasca Bianca , Todan Laura Maghiar , Endres Laura
Published: April 2021

Withaferin A (WFA) was identified as the most active phytocompound of the plant Withania somnifera (WS) and as having multiple therapeutic/ameliorating properties (anticancer, antiangiogenic, anti-invasive, anti-inflammatory, proapoptotic, etc.) in case of various diseases. In drug chemistry, WFA in silico approaches have identified favorite biological targets, stimulating and accelerating research to evaluate its pharmacological activity—numerous anticancer effects manifested in various organs (breast, pancreas, skin, colon, etc.), antivirals, anti-infective, etc., which are not yet sufficiently explored. This paper is a synthesis of the most relevant specialized papers in the field that are focused on the use of WFA in dermatological diseases, describing its mechanism of action while providing, at the same time, details about the results of its testing in in vitro/in vivo studies.
Antihyperglycemic and Antilipidemic Properties of a Tea Infusion of the Leaves from Annona cherimola Miller on Streptozocin-Induced Type 2 Diabetic Mice
Authors: Martínez-Solís Jesús , Calzada Fernando , Barbosa Elizabeth , Valdés Miguel
Published: April 2021

The antihyperglycemic and antilipidemic effects of the tea infusion extracts of leaves from Annona cherimola Miller (IELAc-0.5, IELAc-1.5, and IELAc-3.0) were evaluated on normoglycemic (NG) and streptozocin-induced diabetic (STID) mice. In the acute test, IELAc-1.5 at 300 mg/kg bodyweight (bw) exhibited antihyperglycemic activity on STID mice since the first hour of treatment. Then, its antidiabetic potential was analyzed in a subchronic evaluation. IELAc-1.5 was able to reduce the blood glucose level, glycated hemoglobin (HbA1c), cholesterol (CHO), and triglycerides (TG); high-density lipoprotein (HDL) showed an increase at the end of treatment. IELAc-1.5 did not modify the urine profile at the end of the evaluation, and neither toxicity nor macroscopic organ damage were observed in acute and subchronic assays. In addition, a major flavonol glycoside present in the tea infusion extracts was identified using high-performance liquid chromatography with diode array detection (HPLC-DAD). The analysis of the tea infusion extracts by HPLC revealed that rutin was the major component. This study supports the use of tea infusions from Annona cherimola for the treatment of diabetes and suggests that rutin could be responsible, at least in part, for their antidiabetic properties.
A Spectroscopic Overview of Intramolecular Hydrogen Bonds of NH…O,S,N Type
Authors: Hansen Poul Erik
Published: April 2021

Intramolecular NH…O,S,N interactions in non-tautomeric systems are reviewed in a broad range of compounds covering a variety of NH donors and hydrogen bond acceptors. 1H chemical shifts of NH donors are good tools to study intramolecular hydrogen bonding. However in some cases they have to be corrected for ring current effects. Deuterium isotope effects on 13C and 15N chemical shifts and primary isotope effects are usually used to judge the strength of hydrogen bonds. Primary isotope effects are investigated in a new range of magnitudes. Isotope ratios of NH stretching frequencies, νNH/ND, are revisited. Hydrogen bond energies are reviewed and two-bond deuterium isotope effects on 13C chemical shifts are investigated as a possible means of estimating hydrogen bond energies.
Stochastic Modelling of 13C NMR Spin Relaxation Experiments in Oligosaccharides
Authors: Rampino Sergio , Zerbetto Mirco , Polimeno Antonino
Published: April 2021

A framework for the stochastic description of relaxation processes in flexible macromolecules including dissipative effects has been recently introduced, starting from an atomistic view, describing the joint relaxation of internal coordinates and global degrees of freedom, and depending on parameters recoverable from classic force fields (energetics) and medium modelling at the continuum level (friction tensors). The new approach provides a rational context for the interpretation of magnetic resonance relaxation experiments. In its simplest formulation, the semi-flexible Brownian (SFB) model has been until now shown to reproduce correctly correlation functions and spectral densities related to orientational properties obtained by direct molecular dynamics simulations of peptides. Here, for the first time, we applied directly the SFB approach to the practical evaluation of high-quality 13C nuclear magnetic resonance relaxation parameters, T1 and T2, and the heteronuclear NOE of several oligosaccharides, which were previously interpreted on the basis of refined ad hoc modelling. The calculated NMR relaxation parameters were in agreement with the experimental data, showing that this general approach can be applied to diverse classes of molecular systems, with the minimal usage of adjustable parameters.
The Comparison of Physicochemical Parameters, Antioxidant Activity and Proteins for the Raw Local Polish Honeys and Imported Honey Blends
Authors: Miłek Michał , Bocian Aleksandra , Kleczyńska Ewelina , Sowa Patrycja , Dżugan Małgorzata
Published: April 2021

Many imported honeys distributed on the Polish market compete with local products mainly by lower price, which can correspond to lower quality and widespread adulteration. The aim of the study was to compare honey samples (11 imported honey blends and 5 local honeys) based on their antioxidant activity (measured by DPPH, FRAP, and total phenolic content), protein profile obtained by native PAGE, soluble protein content, diastase, and acid phosphatase activities identified by zymography. These indicators were correlated with standard quality parameters (water, HMF, pH, free acidity, and electrical conductivity). It was found that raw local Polish honeys show higher antioxidant and enzymatic activity, as well as being more abundant in soluble protein. With the use of principal component analysis (PCA) and stepwise linear discriminant analysis (LDA) protein content and diastase number were found to be significant (p < 0.05) among all tested parameters to differentiate imported honey from raw local honeys.
Self-Crosslinked Ellipsoidal Poly(Tannic Acid) Particles for Bio-Medical Applications
Authors: Sahiner Nurettin
Published: April 2021

Self-crosslinking of Tannic acid (TA) was accomplished to obtain poly(tannic acid) (p(TA)) particles in single step, surfactant free media using sodium periodate (NaIO4) as an oxidizing agent. Almost monodisperse p(TA) particles with 981 ± 76 nm sizes and −22 ± 4 mV zeta potential value with ellipsoidal shape was obtained. Only slight degradation of p(TA) particles with 6.8 ± 0.2% was observed at pH 7.4 in PBS up to 15 days because of the irreversible covalent formation between TA units, suggesting that hydrolytic degradation is independent from the used amounts of oxidation agents. p(TA) particles were found to be non-hemolytic up to 0.5 mg/mL concentration and found not to affect blood clotting mechanism up to 2 mg/mL concentration. Antioxidant activity of p(TA) particles was investigated by total phenol content (TPC), ferric reducing antioxidant potential (FRAP), trolox equivalent antioxidant capacity (TEAC), total flavanoid content (TFC), and Fe (II) chelating activity. p(TA) particles showed strong antioxidant capability in comparison to TA molecules, except FRAP assay. The antibacterial activity of p(TA) particles was investigated by micro-dilution technique on E. coli as Gram‑negative and S. aureus as Gram-positive bacteria and found that p(TA) particles are more effective on S. aureus with over 50% inhibition at 20 mg/mL concentration attained.
Prospects for the Personalized Multimodal Therapy Approach to Pain Management via Action on NO and NOS
Authors: Shnayder Natalia A. , Petrova Marina M. , Popova Tatiana E. , Davidova Tatiana K. , Bobrova Olga P. , Trefilova Vera V. , Goncharova Polina S. , Balberova Olga V. , Petrov Kirill V. , Gavrilyuk Oksana A. , Soloveva Irina A. , Medvedev German V. , Nasyrova Regina F.
Published: April 2021

Chronic pain syndromes are an important medical problem generated by various molecular, genetic, and pathophysiologic mechanisms. Back pain, neuropathic pain, and posttraumatic pain are the most important pathological processes associated with chronic pain in adults. Standard approaches to the treatment of them do not solve the problem of pain chronicity. This is the reason for the search for new personalized strategies for the prevention and treatment of chronic pain. The nitric oxide (NO) system can play one of the key roles in the development of peripheral pain and its chronicity. The purpose of the study is to review publications devoted to changes in the NO system in patients with peripheral chronical pain syndromes. We have carried out a search for the articles published in e-Library, PubMed, Oxford Press, Clinical Case, Springer, Elsevier, and Google Scholar databases. The search was carried out using keywords and their combinations. The role of NO and NO synthases (NOS) isoforms in peripheral pain development and chronicity was demonstrated primarily from animal models to humans. The most studied is the neuronal NOS (nNOS). The role of inducible NOS (iNOS) and endothelial NOS (eNOS) is still under investigation. Associative genetic studies have shown that single nucleotide variants (SNVs) of NOS1, NOS2, and NOS3 genes encoding nNOS, iNOS, and eNOS may be associated with acute and chronic peripheral pain. Prospects for the use of NOS inhibitors to modulate the effect of drugs used to treat peripheral pain syndrome are discussed. Associative genetic studies of SNVs NOS1, NOS2, and NOS3 genes are important for understanding genetic predictors of peripheral pain chronicity and development of new personalized pharmacotherapy strategies.
Protective Effect of Cudrania tricuspidata Extract against High-Fat Diet Induced Nonalcoholic Fatty Liver Disease through Nrf-2/HO-1 Pathway
Authors: Shrestha Jitendra , Baek Dong-Jae , Oh Yoon-Sin , Cho Sam-Seok , Ki Sung-Hwan , Park Eun-Young
Published: April 2021

Nonalcoholic fatty liver disease is the most common chronic disease affecting a wide range of the world’s population and associated with obesity-induced metabolic syndrome. It is possibly emerging as a leading cause of life-threatening liver diseases for which a drug with a specific therapeutic target has not been developed yet. Previously, there have been reports on the benefits of Cudrania tricuspidata (CT) for treating obesity and diabetes via regulation of metabolic processes, such as lipogenesis, lipolysis, and inflammation. In this study, we investigated the ameliorative effect of orally administered 0.25% and 0.5% (w/w) CT mixed with high-fat diet (HFD) to C57BL/6J mice for 7 weeks. It was found that body weight, fat mass, hepatic mass, serum glucose level, and liver cholesterol levels were significantly reduced after CT treatment. In CT-treated HFD-fed mice, the mRNA expression levels of hepatic lipogenic and inflammatory cytokine-related genes were markedly reduced, whereas the expression level of epididymal lipogenic genes was increased. The mRNA expression level of beta-oxidation and Nrf-2/HO-1 genes significantly increased in CT-treated obese mice livers. We propose that CT alleviates hepatic steatosis by reducing oxidative stress and inflammation.
Production of Biodegradable Polymer from Agro-Wastes in Alcaligenes sp. and Pseudomonas sp.
Authors: Sayyed R. Z. , Shaikh S. S. , Wani S. J. , Rehman Md Tabish , Al Ajmi Mohammad F. , Haque Shafiul , El Enshasy Hesham Ali
Published: April 2021

The present study was aimed to evaluate the suitability of agro-wastes and crude vegetable oils for the cost-effective production of poly-β-hydroxybutyrate (PHB), to evaluate growth kinetics and PHB production in Alcaligenes faecalis RZS4 and Pseudomonas sp. RZS1 with these carbon substrates and to study the biodegradation of PHB accumulated by these cultures. Alcaligenes faecalis RZS4 and Pseudomonas sp. RZS1 accumulates higher amounts of PHB corn (79.90% of dry cell mass) and rice straw (66.22% of dry cell mass) medium respectively. The kinetic model suggests that the Pseudomonas sp. RZS1 follows the Monod model more closely than A. faecalis RZS4. Both the cultures degrade their PHB extract under the influence of PHB depolymerase. Corn waste and rice straw appear as the best and cost-effective substrates for the sustainable production of PHB from Alcaligenes faecalis RZS4 and Pseudomonas sp. RZS1. The biopolymer accumulated by these organisms is biodegradable in nature. The agro-wastes and crude vegetable oils are good and low-cost sources of nutrients for the growth and production of PHB and other metabolites. Their use would lower the production cost of PHB and the low-cost production will reduce the sailing price of PHB-based products. This would promote the large-scale commercialization and popularization of PHB as an ecofriendly bioplastic/biopolymer.