bluuebunny/crossref_metadata_2025 huggingface dataset:
Mechanochemical P-derivatization of 1,3,5-Triaza-7-Phosphaadamantane (PTA) and Silver-Based Coordination Polymers Obtained from the Resulting Phosphabetaines
Authors: Udvardy Antal , Szolnoki Csenge Tamara , Gombos Réka , Papp Gábor , Kováts Éva , Joó Ferenc , Kathó Ágnes
Published: November 2020

We have described earlier that in aqueous solutions, the reaction of 1,3,5-triaza-7-phosphaadamantane (PTA) with maleic acid yielded a phosphonium-alkanoate zwitterion. The same reaction with 2-methylmaleic acid (citraconic acid) proceeded much slower. It is reported here, that in the case of glutaconic and itaconic acids (constitutional isomers of citraconic acid), formation of the corresponding phosphabetaines requires significantly shorter reaction times. The new phosphabetaines were isolated and characterized by elemental analysis, multinuclear NMR spectroscopy and ESI-MS spectrometry. Furthermore, their molecular structures in the solid state were determined by single crystal X-ray diffraction (SC-XRD). Synthesis of the phosphabetaines from PTA and unsaturated dicarboxylic acids was also carried out mechanochemically with the use of a planetary ball mill, and the characteristics of the syntheses in solvent and under solvent-free conditions were compared. In aqueous solutions, the reaction of the new phosphabetaines with Ag(CF3SO3) yielded Ag(I)-based coordination polymers. According to the SC-XRD results, in these polymers the Ag(I)-ion coordinates to the N and O donor atoms of the ligands; however, Ag(I)-Ag(I) interactions were also identified. The Ag(I)-based coordination polymer (CP1.2) formed with the glutaconyl derivative of PTA (1) showed considerable antimicrobial activity against both Gram-negative and Gram-positive bacteria and yeast strains
Synthesis and Antibacterial Evaluation of New Pyrazolo[3,4-d]pyrimidines Kinase Inhibitors
Authors: Greco Chiara , Catania Rosa , Balacco Dario Leonardo , Taresco Vincenzo , Musumeci Francesca , Alexander Cameron , Huett Alan , Schenone Silvia
Published: November 2020

Pyrazolo[3,4-d]pyrimidines represent an important class of heterocyclic compounds well-known for their anticancer activity exerted by the inhibition of eukaryotic protein kinases. Recently, pyrazolo[3,4-d]pyrimidines have become increasingly attractive for their potential antimicrobial properties. Here, we explored the activity of a library of in-house pyrazolo[3,4-d]pyrimidines, targeting human protein kinases, against Staphylococcus aureus and Escherichia coli and their interaction with ampicillin and kanamycin, representing important classes of clinically used antibiotics. Our results represent a first step towards the potential application of dual active pyrazolo[3,4-d]pyrimidine kinase inhibitors in the prevention and treatment of bacterial infections in cancer patients.
Selective Interactions of O-Methylated Flavonoid Natural Products with Human Monoamine Oxidase-A and -B
Authors: Chaurasiya Narayan D. , Midiwo Jacob , Pandey Pankaj , Bwire Regina N. , Doerksen Robert J. , Muhammad Ilias , Tekwani Babu L.
Published: November 2020

A set of structurally related O-methylated flavonoid natural products isolated from Senecio roseiflorus (1), Polygonum senegalense (2 and 3), Bhaphia macrocalyx (4), Gardenia ternifolia (5), and Psiadia punctulata (6) plant species were characterized for their interaction with human monoamine oxidases (MAO-A and -B) in vitro. Compounds 1, 2, and 5 showed selective inhibition of MAO-A, while 4 and 6 showed selective inhibition of MAO-B. Compound 3 showed ~2-fold selectivity towards inhibition of MAO-A. Binding of compounds 1–3 and 5 with MAO-A, and compounds 3 and 6 with MAO-B was reversible and not time-independent. The analysis of enzyme-inhibition kinetics suggested a reversible-competitive mechanism for inhibition of MAO-A by 1 and 3, while a partially-reversible mixed-type inhibition by 5. Similarly, enzyme inhibition-kinetics analysis with compounds 3, 4, and 6, suggested a competitive reversible inhibition of MAO-B. The molecular docking study suggested that 1 selectively interacts with the active-site of human MAO-A near N5 of FAD. The calculated binding free energies of the O-methylated flavonoids (1 and 4–6) and chalcones (2 and 3) to MAO-A matched closely with the trend in the experimental IC50′s. Analysis of the binding free-energies suggested better interaction of 4 and 6 with MAO-B than with MAO-A. The natural O-methylated flavonoid (1) with highly potent inhibition (IC50 33 nM; Ki 37.9 nM) and >292 fold selectivity against human MAO-A (vs. MAO-B) provides a new drug lead for the treatment of neurological disorders.
Anticancer Drug Discovery from Microbial Sources: The Unique Mangrove Streptomycetes
Authors: Law Jodi Woan-Fei , Law Lydia Ngiik-Shiew , Letchumanan Vengadesh , Tan Loh Teng-Hern , Wong Sunny Hei , Chan Kok-Gan , Ab Mutalib Nurul-Syakima , Lee Learn-Han
Published: November 2020

Worldwide cancer incidence and mortality have always been a concern to the community. The cancer mortality rate has generally declined over the years; however, there is still an increased mortality rate in poorer countries that receives considerable attention from healthcare professionals. This suggested the importance of the prompt detection, effective treatment, and prevention strategies. The genus Streptomyces has been documented as a prolific producer of biologically active secondary metabolites. Streptomycetes from mangrove environments attract researchers’ attention due to their ability to synthesize diverse, interesting bioactive metabolites. The present review highlights research on mangrove-derived streptomycetes and the production of anticancer-related compounds from these microorganisms. Research studies conducted between 2008 and 2019, specifically mentioning the isolation of streptomycetes from mangrove areas and described the successful purification of compound(s) or generation of crude extracts with cytotoxic activity against human cancer cell lines, were compiled in this review. It is anticipated that there will be an increase in prospects for mangrove-derived streptomycetes as one of the natural resources for the isolation of chemotherapeutic agents.
Characterization of Inherently Chiral Electrosynthesized Oligomeric Films by Voltammetry and Scanning Electrochemical Microscopy (SECM)
Authors: Donnici Margherita , Toniolo Rosanna , Arnaboldi Serena , Mussini Patrizia R. , Benincori Tiziana , Cirilli Roberto , Daniele Salvatore
Published: November 2020

A voltammetric and scanning electrochemical microscopy (SECM) investigation was performed on an inherently chiral oligomer-coated gold electrode to establish its general properties (i.e., conductivity and topography), as well as its ability to discriminate chiral electroactive probe molecules. The electroactive monomer (S)-2,2′-bis(2,2′-bithiophene-5-yl)-3,3′-bibenzothiophene ((S)-BT2T4) was employed as reagent to electrodeposit, by cyclic voltammetry, the inherently chiral oligomer film of (S)-BT2T4 (oligo-(S)-BT2T4) onto the Au electrode surface (resulting in oligo-(S)-BT2T4-Au). SECM measurements, performed in either feedback or competition mode, using the redox mediators [Fe(CN)6]4− and [Fe(CN)6]3− in aqueous solutions, and ferrocene (Fc), (S)-FcEA, (R)-FcEA and rac-FcEA (FcEA is N,N-dimethyl-1-ferrocenylethylamine) in CH3CN solutions, indicated that the oligomer film, as produced, was uncharged. The use of [Fe(CN)6]3− allowed establishing that the oligomer film behaved as a porous insulating membrane, presenting a rather rough surface. This was inferred from both the approach curves and linear and bidimensional SECM scans, which displayed negative feedback effects. The oligomer film acquired semiconducting or fully conducting properties when the Au electrode was biased at potential more positive than 0.6 V vs. Ag|AgCl|KCl. Under the latter conditions, the approach curves displayed positive feedback effects. SECM measurements, performed in competition mode, allowed verifying the discriminating ability of the oligo-(S)-BT2T4 film towards the (S)-FcEA and (R)-FcEA redox mediators, which confirmed the results obtained by cyclic voltammetry. SECM linear scans indicated that the enantiomeric discriminating ability of the oligo-(S)-BT2T4 was even across its entire surface.
Diffusion of Quinine with Ethanol as a Co-Solvent in Supercritical CO2
Authors: Gaponenko Yury , Mialdun Aliaksandr , Shevtsova Valentina
Published: November 2020

This study aims at contributing to quinine extraction using supercritical CO2 and ethanol as a co-solvent. The diffusion coefficients of quinine in supercritical CO2 are measured using the Taylor dispersion technique when quinine is pre-dissolved in ethanol. First, the diffusion coefficients of pure ethanol in the supercritical state of CO2 were investigated in order to get a basis for seeing a relative change in the diffusion coefficient with the addition of quinine. We report measurements of the diffusion coefficients of ethanol in scCO2 in the temperature range from 304.3 to 343 K and pressures of 9.5, 10 and 12 MPa. Next, the diffusion coefficients of different amounts of quinine dissolved in ethanol and injected into supercritical CO2 were measured in the same range of temperatures at p = 12 Mpa. At the pressure p = 9.5 MPa, which is close to the critical pressure, the diffusion coefficients were measured at the temperature, T = 343 K, far from the critical value. It was found that the diffusion coefficients are significantly dependent on the amount of quinine in a small range of its content, less than 0.1%. It is quite likely that this behavior is associated with a change in the spatial structure, that is, the formation of clusters or compounds, and a subsequent increase in the molecular weight of the diffusive substance.
Neuroprotective Activities of Boophone haemanthoides (Amaryllidaceae) Extract and Its Chemical Constituents
Authors: Ibrakaw Abobaker S. , Omoruyi Sylvester I. , Ekpo Okobi E. , Hussein Ahmed A.
Published: November 2020

Parkinson’s disease (PD) is a neurodegenerative condition that progresses as age increases, and some of its major symptoms include tremor and postural and movement-related difficulties. To date, the treatment of PD remains a challenge because available drugs only treat the symptoms of the disease or possess serious side effects. In light of this, new treatment options are needed; hence, this study investigates the neuroprotective effects of an organic Boophone haemanthoides extract (BHE) and its bioactive compounds using an in vitro model of PD involving the toxin 1-methyl-4-phenylpyridinium (MPP+) and SH-SY5Y neuroblastoma cells. A total of seven compounds were isolated from BHE, viz distichamine (1), 1α,3α-diacetylnerbowdine (2), hippadine (3), stigmast-4-ene-3,6-dione (4), cholest-4-en-3-one (5), tyrosol (6), and 3-hydroxy-1-(4′-hydroxyphenyl)-1-propanone (7). Six compounds (1, 2, 4, 5, 6 and 7) were investigated, and five showed neuroprotection alongside the BHE. This study gives insight into the bioactivity of the non-alkaloidal constituents of Amaryllidaceae, since the isolated compounds and the BHE showed improved cell viability, increased ATP generation in the cells as well as inhibition of MPP+-induced apoptosis. Together, these findings support the claim that the Amaryllidaceae plant family could be a potential reserve of bioactive compounds for the discovery of neuroprotective agents.
Application of New Efficient Hoveyda–Grubbs Catalysts Comprising an N→Ru Coordinate Bond in a Six-Membered Ring for the Synthesis of Natural Product-Like Cyclopenta[b]furo[2,3-c]pyrroles
Authors: Antonova Alexandra S. , Vinokurova Marina A. , Kumandin Pavel A. , Merkulova Natalia L. , Sinelshchikova Anna A. , Grigoriev Mikhail S. , Novikov Roman A. , Kouznetsov Vladimir V. , Polyanskii Kirill B. , Zubkov Fedor I.
Published: November 2020

The ring rearrangement metathesis (RRM) of a trans-cis diastereomer mixture of methyl 3-allyl-3a,6-epoxyisoindole-7-carboxylates derived from cheap, accessible and renewable furan-based precursors in the presence of a new class of Hoveyda–Grubbs-type catalysts, comprising an N→Ru coordinate bond in a six-membered ring, results in the difficult-to-obtain natural product-like cyclopenta[b]furo[2,3-c]pyrroles. In this process, only one diastereomer with a trans-arrangement of the 3-allyl fragment relative to the 3a,6-epoxy bridge enters into the rearrangement, while the cis-isomers polymerize almost completely under the same conditions. The tested catalysts are active in the temperature range from 60 to 120 °C at a concentration of 0.5 mol % and provide better yields of the target tricycles compared to the most popular commercially available second-generation Hoveyda–Grubbs catalyst. The diastereoselectivity of the intramolecular Diels–Alder reaction furan (IMDAF) reaction between starting 1-(furan-2-yl)but-3-en-1-amines and maleic anhydride, leading to 3a,6-epoxyisoindole-7-carboxylates, was studied as well.
Two Decades of Touchable and Walkable Virtual Reality for Blind and Visually Impaired People: A High-Level Taxonomy
Authors: Kreimeier Julian , Götzelmann Timo
Published: November 2020

Although most readers associate the term virtual reality (VR) with visually appealing entertainment content, this technology also promises to be helpful to disadvantaged people like blind or visually impaired people. While overcoming physical objects’ and spaces’ limitations, virtual objects and environments that can be spatially explored have a particular benefit. To give readers a complete, clear and concise overview of current and past publications on touchable and walkable audio supplemented VR applications for blind and visually impaired users, this survey paper presents a high-level taxonomy to cluster the work done up to now from the perspective of technology, interaction and application. In this respect, we introduced a classification into small-, medium- and large-scale virtual environments to cluster and characterize related work. Our comprehensive table shows that especially grounded force feedback devices for haptic feedback (‘small scale’) were strongly researched in different applications scenarios and mainly from an exocentric perspective, but there are also increasingly physically (‘medium scale’) or avatar-walkable (‘large scale’) egocentric audio-haptic virtual environments. In this respect, novel and widespread interfaces such as smartphones or nowadays consumer grade VR components represent a promising potential for further improvements. Our survey paper provides a database on related work to foster the creation process of new ideas and approaches for both technical and methodological aspects.
Novel Benchtop Magnetic Particle Spectrometer for Process Monitoring of Magnetic Nanoparticle Synthesis
Authors: Löwa Norbert , Gutkelch Dirk , Welge Ernst-Albrecht , Welz Roland , Meier Florian , Baki Abdulkader , Bleul Regina , Klein Thorsten , Wiekhorst Frank
Published: November 2020

Magnetic nanoparticles combine unique magnetic properties that can be used in a variety of biomedical applications for therapy and diagnostics. These applications place high demands on the magnetic properties of nanoparticles. Thus, research, development, and quality assurance of magnetic nanoparticles requires powerful analytical methods that are capable of detecting relevant structural and, above all, magnetic parameters. By directly coupling nanoparticle synthesis with magnetic detectors, relevant nanoparticle properties can be obtained and evaluated, and adjustments can be made to the manufacturing process in real time. This work presents a sensitive and fast magnetic detector for online characterization of magnetic nanoparticles during their continuous micromixer synthesis. The detector is based on the measurement of the nonlinear dynamic magnetic response of magnetic nanoparticles exposed to an oscillating excitation at a frequency of 25 kHz, a technique also known as magnetic particle spectroscopy. Our results underline the excellent suitability of the developed magnetic online detection for coupling with magnetic nanoparticle synthesis based on the micromixer approach. The proven practicability and reliability of the detector for process monitoring forms the basis for further application fields, e.g., as a monitoring tool for chromatographic separation processes.
A Combined Tie-Fastening Method for the Reusable Surgical Gown with Two Neck Tie Belts to Improve Wearing Comfort
Authors: Chang Kai-Hui , Chen Yu-Ling , Dai Shu-Yi
Published: November 2020

The reusable surgical gowns made of slippery materials have the tendency to slip down as they are being worn. The rear neck tie(s) can sometimes loosen, and this causes the surgical gown to slip down somewhat, making the surgical staff members feel uncomfortable. If the gowns have two rear neck ties with a tendency of loosening and allowing the gowns to slip down, the surgical staff members feel more uncomfortable when there is only one tie loosening but the other tie is tethering. To fasten the neck ties of the surgical gown with two neck tie belts, we propose a simplified method of fastening the two sets of tie belts together as one tie, instead of fastening them separately. The object of this study is to evaluate this combined tying method for its ability to secure the gown and its wearing comfort. We enrolled five volunteers to evaluate the tie loosening condition of the reusable surgical gowns with two sets of rear neck tie belts after a series of upper limb motion exercises while wearing and not wearing the X-ray protective apron beneath the gown. The amount of uppermost rear neck cloth edge separation was recorded before and after the exercise. We also evaluated the wearing comfort of five enrolled operating surgeons for comparing the original and this modified tying method while wearing and not wearing the X-ray protective apron. In the results, we found that combined tying tends to have significantly more rear gown separation (0.94 cm) than separate tying (0.27 cm) after vigorous upper extremities exercise. However, during the actual performance of the surgeries, the rear neck tie(s) loosening and wearing discomfort of the combined tying method was significantly less than using the separate tying method (loosening: 0% vs. 30%) (discomfort: 0% vs. 35%) while the X-ray protective apron was not worn. For reusable surgical gowns that have two rear neck ties, we suggest the two sets of rear neck ties could be fastened together as one combined tie in routine surgical practice. With this, tying could be performed easier and faster, and wearing comfort could be improved.
Candidate Gene Markers Associated with Fecal Shedding of the Feline Enteric Coronavirus (FECV)
Authors: Bubenikova Jana , Vrabelova Jana , Stejskalova Karla , Futas Jan , Plasil Martin , Cerna Petra , Oppelt Jan , Lobova Dana , Molinkova Dobromila , Horin Petr
Published: November 2020

The Feline coronavirus (FCoV) can cause a fatal disease, the Feline Infectious Peritonitis. Persistent shedders represent the most important source of infection. The role of the host in FCoV fecal shedding is unknown. The objective of this study was to develop gene markers and to test their associations with FCoV shedding patterns. Fecal samples were taken from 57 cats of 12 breeds on the day 0 and after 2, 4 and 12 months. Variation from persistent and/or high-intensity shedding to no shedding was observed. Thirteen immunity-related genes were selected as functional and positional/functional candidates. Positional candidates were selected in a candidate region detected by a GWAS analysis. Tens to hundreds of single nucleotide polymorphisms (SNPs) per gene were identified using next generation sequencing. Associations with different phenotypes were assessed by chi-square and Fisher’s exact tests. SNPs of one functional and one positional candidate (NCR1 and SLX4IP, respectively) and haplotypes of four genes (SNX5, NCR2, SLX4IP, NCR1) were associated with FCoV shedding at pcorected < 0.01. Highly significant associations were observed for extreme phenotypes (persistent/high-intensity shedders and non-shedders) suggesting that there are two major phenotypes associated with different genotypes, highly susceptible cats permanently shedding high amounts of viral particles and resistant non-shedders.
Introducing Pediatric Reports: Only Another Pediatric Journal?
Authors: Aricò Maurizio
Published: November 2020

The purpose of this editorial is to introduce Pediatric Reports, a 10-year-old journal that is now at a turning point [...]
Using Carbomer-Based Hydrogels for Control the Release Rate of Diclofenac Sodium: Preparation and In Vitro Evaluation
Authors: Suhail Muhammad , Wu Pao-Chu , Minhas Muhammad Usman
Published: November 2020

The aim of the current research work was to prepare Car934-g-poly(acrylic acid) hydrogels by the free-radical polymerization technique. Various concentrations of carbopol, acrylic acid and ethylene glycol dimethacrylate were employed for the fabrication of Car934-g-poly(acrylic acid) hydrogels. Fourier-transform infrared spectroscopy (FTIR), Thermogravimetric analysis (TGA), Differential scanning calorimetry (DSC), Scanning electron microscope (SEM) and Powder X-ray diffractometry (PXRD) studies were performed to know the structural arrangement, thermal stability, physical appearance and amorphous network of developed hydrogels. FTIR analysis revealed that carbopol reacted with acrylic acid during the process of polymerization and confirmed the grafting of acrylic acid over the backbone of carbopol. TGA and DSC studies showed that developed hydrogels were thermally stable. Surface morphology was analyzed by SEM, which confirmed a porous network of hydrogels. PXRD analysis indicated that crystallinity of the drug was reduced by the amorphous network of hydrogels. Furthermore, swelling studies for all developed hydrogels were performed at both media, i.e., pH 1.2 and 7.4, and higher swelling was exhibited at pH 7.4. Sol–gel analysis was performed to evaluate the soluble unreacted part of the fabricated hydrogels. Similarly, an in-vitro study was conducted for all hydrogel formulations at both acidic (pH 1.2) and basic (pH 7.4) mediums, and a greater drug release was observed at pH 7.4. Different kinetics such as zero-order, first-order, the Higuchi model and the Korsmeyer–Peppas model were applied to know the mechanism of release order of drugs from the hydrogels.
The Impact of the Addition of Compatibilizers on Poly (lactic acid) (PLA) Properties after Extrusion Process
Authors: Gonçalves F.A.M.M. , Cruz Sandra M. A. , Coelho Jorge F. J. , Serra Arménio C.
Published: November 2020

Poly (lactic acid) (PLA), due to its biodegradability, biocompatibility, and renewability, is one of the most promising biobased polymers for replacing some of the petrol-based materials. Low flexibility of PLA is overcome, by blending it with olefin-based polymers, such as polypropylene (PP). However, the use of compatibilizing agents is required to attain final materials with suitable mechanical properties. Such agents, although essential, can affect PLA structure and, consequently, the mechanical properties of the PLA. To the best of our knowledge, this issue was never studied, and the results can contribute to achieving the best formulations of PLA-based blends according to their final applications. The thermal and mechanical properties of the extruded PLA, with three different commercial compatibilizing agents, were evaluated with the purpose of demonstrating how the compatibilizers can introduce structural differences into the PLA chain during the extrusion process. The combination of crystallinity, molecular weight, and the morphology of the samples after extrusion determines the final mechanical properties of PLA. Despite being a fundamental study, it is our aim to contribute to the sustainability of PLA-based industries. The addition of a 2.5% concentration of C1 compatibilizer seems to have less influence on the final morphology and mechanical properties of the blends.
Cellular Polyolefin Composites as Piezoelectric Materials: Properties and Applications
Authors: Klimiec Ewa , Kaczmarek Halina , Królikowski Bogusław , Kołaszczyński Grzegorz
Published: November 2020

Piezoelectric polymers characterized by flexibility are sought for applications in microelectronics, medicine, telecommunications, and everyday devices. The objective of this work was to obtain piezoelectric polymeric composites with a cellular structure and to evaluate their usefulness in practice. Composites based on polyolefins (isotactic-polypropylene and polyethylene) with the addition of aluminosilicate fillers were manufactured by extrusion, and then polarized in a constant electric field at 100 V/µm. The content of mineral fillers up to 10 wt% in the polymer matrix enhances its electric stability and mechanical strength. The value of the piezoelectric coefficient d33 attained ~150 pC/N in the range of lower stresses and ~80 pC/N in the range of higher stresses, i.e., at ~120 kPa. The materials exhibited high durability in time, therefore, they can be used as transducers of mechanical energy of the human motion into electric energy. It was demonstrated that one shoe insert generates an energy of 1.1 mJ after a person walks for 300 s. The miniaturized integrated circuits based on polyolefin composites may be applied for the power supply of portable electronics. Due to their high sensitivity, they can be recommended for measuring the blood pulse.
Nanocomposite Materials with Poly(l-lactic Acid) and Transition-Metal Dichalcogenide Nanosheets 2D-TMDCs WS2
Authors: Naffakh Mohammed , Fernández Miriam , Shuttleworth Peter S. , García Ana M. , Moreno Diego A.
Published: November 2020

Layered transition-metal dichalcogenides (TMDCs) based on tungsten disulfide nanosheets (2D-WS2) were introduced via melt processing into poly(l-lactic acid) (PLLA) to generate PLLA/2D-WS2 nanocomposite materials. The effects of the 2D-WS2 on the morphology, crystallization, and biodegradation behavior of PLLA were investigated. In particular, the non-isothermal melt-crystallization of neat PLLA and PLLA/2D-WS2 nanocomposites were analyzed in detail by varying both the cooling rate and 2D-WS2 loading. The kinetic parameters of PLLA chain crystallization are successfully described using the Liu model. It was found that the PLLA crystallization rate was reduced with 2D-WS2 incorporation, while the crystallization mechanism and crystal structure of PLLA remained unchanged in spite of nanoparticle loading. This was due to the PLLA chains not being able to easily adsorb on the WS2 nanosheets, hindering crystal growth. In addition, from surface morphology analysis, it was observed that the addition of 2D-WS2 facilitated the enzymatic degradation of poorly biodegradable PLLA using a promising strain of actinobacteria, Lentzea waywayandensis. The identification of more suitable enzymes to break down PLLA nanocomposites will open up new avenues of investigation and development, and it will also lead to more environmentally friendly, safer, and economic routes for bioplastic waste management.
An Overview on Personal Protective Equipment (PPE) Fabricated with Additive Manufacturing Technologies in the Era of COVID-19 Pandemic
Authors: Rendeki Szilard , Nagy Balint , Bene Matyas , Pentek Attila , Toth Luca , Szanto Zalan , Told Roland , Maroti Peter
Published: November 2020

Different additive manufacturing technologies have proven effective and useful in remote medicine and emergency or disaster situations. The coronavirus disease 2019 (COVID-19) disease, caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) virus, has had a huge impact on our society, including in relation to the continuous supply of personal protective equipment (PPE). The aim of the study is to give a detailed overview of 3D-printed PPE devices and provide practical information regarding the manufacturing and further design process, as well as describing the potential risks of using them. Open-source models of a half-face mask, safety goggles, and a face-protecting shield are evaluated, considering production time, material usage, and cost. Estimations have been performed with fused filament fabrication (FFF) and selective laser sintering (SLS) technology, highlighting the material characteristics of polylactic acid (PLA), polyamide, and a two-compound silicone. Spectrophotometry measurements of transparent PMMA samples were performed to determine their functionality as goggles or face mask parts. All the tests were carried out before and after the tetra-acetyl-ethylene-diamine (TAED)-based disinfection process. The results show that the disinfection has no significant effect on the mechanical and structural stability of the used polymers; therefore, 3D-printed PPE is reusable. For each device, recommendations and possible means of development are explained. The files of the modified models are provided. SLS and FFF additive manufacturing technology can be useful tools in PPE development and small-series production, but open-source models must be used with special care.
Numerical Analysis of the Contact Behavior of a Polymer-Based Waterproof Membrane for Tunnel Lining
Authors: Lee Kicheol , Kim Dongwook , Choi Soon-Wook , Chang Soo-Ho , Kang Tae-Ho , Lee Chulho
Published: November 2020

Waterproof membranes have higher initial strength, faster construction, and better waterproofing than conventional sheet membranes. In addition, their polymer constituents have much higher interfacial adhesion and tensile strength than those of conventional materials. However, despite their advantages, waterproof membranes are not widely used in civil construction. This study evaluates the material properties and interface parameters of a waterproof membrane by considering the results of laboratory experiments and numerical analysis. Since the contact behavior of a membrane at its interface with shotcrete is important for understanding the mechanism of the support it offers known as a shotcrete tunnel lining, modeling should adopt appropriate contact conditions. The numerical analysis identifies the suitability and contact conditions of the waterproof membrane in various conditions.
Coupled Anisotropic Magneto-Mechanical Material Model for Structured Magnetoactive Materials
Authors: Dohmen Eike , Kraus Benjamin
Published: November 2020

Adaptability of properties of magnetic materials such as magnetorheological (MR) fluids, MR elastomers (MRE), and other magneto-active (MA) materials drives scientific activities worldwide, trying to broaden the fields of application of such materials. In our work, we focused on the utilization and implementation of existing material models to realize a praxis-oriented coupled anisotropic material model for the commercial finite element (FE) software ABAQUS taking into account magneto-mechanical interactions. By introducing this material model, a first step is done to predict and optimize the behavior of MA materials.
A Novel Microfiber Wipe for Delivery of Active Substances to Human Skin: Clinical Proof of Concept
Authors: Kaegi Martin , Adlhart Christian , Lehmann Markus , Risch Marius , Wessling Werner , Klaffenbach Peter
Published: November 2020

A novel technology for the delivery of active substances to the skin based on microfibers loaded with dried active substances was developed. The objective of this work was to demonstrate deposition of the active substances on the skin including concurrent cleansing properties of the wipe. As model active substance to measure deposition capacity Niacinamide was used and as parameter to measure cleansing capacities of the wipe squalene uptake was measured. Wipes loaded with niacinamide were used in the face and the forearm of 25 subjects. By means of Raman spectrometry the deposited niacinamide was analyzed before and after application. Wipes used on the face were analyzed for squalene to assess skin cleansing properties and for residual niacinamide. Forearm analysis including placebo and verum on left and right arm respectively was performed to rule out changes of the skin through application of the tissue. Measured amounts of niacinamide from face application demonstrate statistically significant results in the study population. Analysis of the wipes used show a liberation of 28.3% of niacinamide from the wipes and an uptake of 1.7 mg squalene per wipe. Results from forearm application show statistically significant differences (p < 0.05) between placebo and active for the complete study population. Sub group analyses are significant for both gender and ethnicity for face and forearm analysis respectively. Results clearly demonstrate deposition of niacinamide on the skin and the cleansing properties of the wipe. The institutional review board approved this prospective study.
Chitosan-GPTMS-Silica Hybrid Mesoporous Aerogels for Bone Tissue Engineering
Authors: Reyes-Peces María V. , Pérez-Moreno A. , de-los-Santos Deseada María , Mesa-Díaz María del Mar , Pinaglia-Tobaruela Gonzalo , Vilches-Pérez Jose Ignacio , Fernández-Montesinos Rafael , Salido Mercedes , de la Rosa-Fox Nicolás , Piñero Manuel
Published: November 2020

This study introduces a new synthesis route for obtaining homogeneous chitosan (CS)-silica hybrid aerogels with CS contents up to 10 wt%, using 3-glycidoxypropyl trimethoxysilane (GPTMS) as coupling agent, for tissue engineering applications. Aerogels were obtained using the sol-gel process followed by CO2 supercritical drying, resulting in samples with bulk densities ranging from 0.17 g/cm3 to 0.38 g/cm3. The textural analysis by N2-physisorption revealed an interconnected mesopore network with decreasing specific surface areas (1230–700 m2/g) and pore sizes (11.1–8.7 nm) by increasing GPTMS content (2–4 molar ratio GPTMS:CS monomer). In addition, samples exhibited extremely fast swelling by spontaneous capillary imbibition in PBS solution, presenting swelling capacities from 1.75 to 3.75. The formation of a covalent crosslinked hybrid structure was suggested by FTIR and confirmed by an increase of four hundred fold or more in the compressive strength up to 96 MPa. Instead, samples synthesized without GPTMS fractured at only 0.10–0.26 MPa, revealing a week structure consisted in interpenetrated polymer networks. The aerogels presented bioactivity in simulated body fluid (SBF), as confirmed by the in vitro formation of hydroxyapatite (HAp) layer with crystal size of approximately 2 µm size in diameter. In vitro studies revealed also non cytotoxic effect on HOB® osteoblasts and also a mechanosensitive response. Additionally, control cells grown on glass developed scarce or no stress fibers, while cells grown on hybrid samples showed a significant (p < 0.05) increase in well-developed stress fibers and mature focal adhesion complexes.
Experimental and Numerical Simulation Study of Devolatilization in a Self-Wiping Corotating Parallel Twin-Screw Extruder
Authors: Ohara Masatoshi , Sasai Yuya , Umemoto Sho , Obata Yuya , Sugiyama Takemasa , Tanifuji Shin-ichiro , Kihara Shin-ichi , Taki Kentaro
Published: November 2020

Devolatilization is an important process for separating and removing unnecessary residual volatile substances or solvents during the production of polymers using twin-screw extruders. Latinen proposed a surface renewal model to determine the concentration of volatile components in the extrudate of a single-screw extruder. When a twin-screw extruder is used to calculate the concentration, it is necessary to use the exposed surface area of the resin in the starved region of Latinen’s model, which, however, is difficult to estimate. In our previous work, we numerically determined resin profiles of the screws using the 2.5D Hele–Shaw flow model and the finite element method, which helps in estimating the surface area of devolatilization. In this study, we numerically analyzed the volatile concentration of the extrudate in a self-wiping corotating twin-screw extruder using Latinen’s surface renewal model along with our resin profile calculation method. The experimental results of the concentrations of the volatile component (toluene) in the extrudate of polypropylene agreed well with its numerical calculation with a relative error of 6.5% (except for the data of the lowest rotational speed). Our results also showed that decreasing the flow rate and increasing the pump capacity were effective for removing the volatile component. The screw pitch of a full-flight screw was not affected by the devolatilization efficiency with a fixed flow rate and screw speed.
Analysis of Selected Physicochemical Properties of Commercial Apple Juices
Authors: Rydzak Leszek , Kobus Zbigniew , Nadulski Rafał , Wilczyński Kamil , Pecyna Anna , Santoro Francesco , Sagan Agnieszka , Starek-Wójcicka Agnieszka , Krzywicka Monika
Published: November 2020

The paper presents the comparison of quality of six different commercial apple juices produced in Poland. The apple juices came from two different Polish companies. From each manufacturer three various juices were selected: two cloudy and clarified one produced as a mixture of different apple varieties. The following properties were evaluated: density, soluble solid content, viscosity, total phenolic contents, phenolic acid, and antiradical activity. The obtained results showed that three from fourth cloudy juices (M1Sz, M1A and M2A) differed from clarified juices. The highest differences were noticed for total phenolic contents, phenolic acids, antiradical activity and viscosity. The values of these properties ranged between 60.72–103.6 mg GAE·100−1 mL−1 for phenolic contents, 78.3–90.9% for antiradical activity and 2.68–5.79 mPa·s for viscosity. The remaining cloudy juice (M2Sz) was more similar to the clarified ones. The strong correlation between total phenolic content and antiradical activity of apple juices was found. The high correlation coefficient obtained between these features indicates that both producers do not apply excessive amounts of vitamin C during the production of cloudy apple juices. There was also a strong interrelation between the density of juice and solid soluble content. However, no correlation was found between the solid soluble content and the viscosity of the tested juices.
Scutellaria baicalensis Flavones as Potent Drugs against Acute Respiratory Injury during SARS-CoV-2 Infection: Structural Biology Approaches
Authors: Udrea Ana-Maria , Mernea Maria , Buiu Cătălin , Avram Speranța
Published: November 2020

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection can result in severe damage to the respiratory system. With no specific treatment to date, it is crucial to identify potent inhibitors of SARS-CoV-2 Chymotrypsin-like protease (3CLpro) that could also modulate the enzymes involved in the respiratory damage that accompanies SARS-CoV-2 infection. Here, flavones isolated from Scutellaria baicalensis (baicalein, baicalin, wogonin, norwogonin, and oroxylin A) were studied as possible compounds in the treatment of SARS-CoV-2 and SARS-CoV-2-induced acute lung injuries. We used structural bioinformatics and cheminformatics to (i) identify the critical molecular features of flavones for their binding activity at human and SARS-CoV-2 enzymes; (ii) predict their drug-likeness and lead-likeness features; (iii) calculate their pharmacokinetic profile, with an emphasis on toxicology; (iv) predict their pharmacodynamic profiles, with the identification of their human body targets involved in the respiratory system injuries; and (v) dock the ligands to SARS-CoV-2 3CLpro. All flavones presented appropriate drug-like and kinetics features, except for baicalin. Flavones could bind to SARS-CoV-2 3CLpro at a similar site, but interact slightly differently with the protease. Flavones’ pharmacodynamic profiles predict that (i) wogonin strongly binds at the cyclooxygenase2 and nitric oxide synthase; (ii) baicalein and norwogonin could modulate lysine-specific demethylase 4D-like and arachidonate 15-lipoxygenase; and (iii) baicalein, wogonin, norwogonin, and oroxylin A bind to SARS-CoV-2 3CLpro. Our results propose these flavones as possible potent drugs against respiratory damage that occurs during SARS-CoV-2 infections, with a strong recommendation for baicalein.
An Earlier Copy of al-Suhrawardī’s ʿAwārif al-Maʿārif and Its Scribe, Abū Ṭāhir al-Ḥanafī
Authors: Kars Aydogan
Published: November 2020

This paper introduces an accomplished Ḥanafī traditionist [muḥaddith] named Abū Ṭāhir ʿAbd al-Salām Ibn Abī al-Rabīʿ al-Shīrāzī (b.bef.590/1194, d.661/1263), and two newly-discovered manuscripts that shed light on his life, works, and networks. The first manuscript is an earlier copy of ʿUmar al-Suhrawardī’s (539-632/1145-1234) influential Sufi treatise, Benefits of Intimate Knowledge [ʿAwārif al-Maʿārif] that Abū Ṭāhir copied in 603/1206. In addition to updating the terminus ad quem of al-Suhrawardī’s masterpiece, the manuscript also preserves a significant audition [samāʿ] record. While Abū Ṭāhir transcribed this early copy, he seems to have neither participated in the later transmission of the work nor formed a Sufi identity. A well-connected traditionist who has not yet received scholarly attention, he wrote many works, none of which have been studied so far. This paper introduces his life and works, traces his immediate teachers and pupils in transmitting prophetic sayings, and analyzes a hitherto unstudied manuscript of his Forty Sayings on the Virtue of Praying for the Messenger of God [Al-Arbaʿūn fī Faḍīlat al-Ṣalāt ʿalā Rasūl Allāh]. The paper demonstrates that the study of al-Suhrawardī’s ʿAwārif al-Maʿārif by non-Sufi traditionists can be traced back to its earliest extant copy available to us.
Geodetic SAR for Height System Unification and Sea Level Research—Observation Concept and Preliminary Results in the Baltic Sea
Authors: Gruber Thomas , Ågren Jonas , Angermann Detlef , Ellmann Artu , Engfeldt Andreas , Gisinger Christoph , Jaworski Leszek , Marila Simo , Nastula Jolanta , Nilfouroushan Faramarz , Oikonomidou Xanthi , Poutanen Markku , Saari Timo , Schlaak Marius , Światek Anna , Varbla Sander , Zdunek Ryszard
Published: November 2020

Traditionally, sea level is observed at tide gauge stations, which usually also serve as height reference stations for national leveling networks and therefore define a height system of a country. One of the main deficiencies to use tide gauge data for geodetic sea level research and height systems unification is that only a few stations are connected to the geometric network of a country by operating permanent GNSS receivers next to the tide gauge. As a new observation technique, absolute positioning by SAR using active transponders on ground can fill this gap by systematically observing time series of geometric heights at tide gauge stations. By additionally knowing the tide gauge geoid heights in a global height reference frame, one can finally obtain absolute sea level heights at each tide gauge. With this information the impact of climate change on the sea level can be quantified in an absolute manner and height systems can be connected across the oceans. First results from applying this technique at selected tide gauges at the Baltic coasts are promising but also exhibit some problems related to the new technique. The paper presents the concept of using the new observation type in an integrated sea level observing system and provides some early results for SAR positioning in the Baltic sea area.
A Slimmer Network with Polymorphic and Group Attention Modules for More Efficient Object Detection in Aerial Images
Authors: Guo Wei , Li Weihong , Li Zhenghao , Gong Weiguo , Cui Jinkai , Wang Xinran
Published: November 2020

Object detection is one of the core technologies in aerial image processing and analysis. Although existing aerial image object detection methods based on deep learning have made some progress, there are still some problems remained: (1) Most existing methods fail to simultaneously consider multi-scale and multi-shape object characteristics in aerial images, which may lead to some missing or false detections; (2) high precision detection generally requires a large and complex network structure, which usually makes it difficult to achieve the high detection efficiency and deploy the network on resource-constrained devices for practical applications. To solve these problems, we propose a slimmer network for more efficient object detection in aerial images. Firstly, we design a polymorphic module (PM) for simultaneously learning the multi-scale and multi-shape object features, so as to better detect the hugely different objects in aerial images. Then, we design a group attention module (GAM) for better utilizing the diversiform concatenation features in the network. By designing multiple detection headers with adaptive anchors and the above-mentioned two modules, we propose a one-stage network called PG-YOLO for realizing the higher detection accuracy. Based on the proposed network, we further propose a more efficient channel pruning method, which can slim the network parameters from 63.7 million (M) to 3.3M that decreases the parameter size by 94.8%, so it can significantly improve the detection efficiency for real-time detection. Finally, we execute the comparative experiments on three public aerial datasets, and the experimental results show that the proposed method outperforms the state-of-the-art methods.
Characteristics of the Residual Surface Deformation of Multiple Abandoned Mined-Out Areas Based on a Field Investigation and SBAS-InSAR: A Case Study in Jilin, China
Authors: Chen Donghui , Chen Huie , Zhang Wen , Cao Chen , Zhu Kuanxing , Yuan Xiaoqing , Du Yanyan
Published: November 2020

Residual surface deformation resulting from abandoned mined-out areas can lead to severe damage to ground structures (e.g., buildings and infrastructure in mining areas) and the local ecological environment. Long-term monitoring and analyses of surface deformation characteristics of abandoned mined-out areas are significant for preventing potential disasters. In this study, a detailed field investigation first was conducted in Ying’an and Baoshan coal mines located in Jilin Province, China, to survey mining-induced disasters in the mining areas. Based on the 40 Sentinel-1A images acquired from 14 February 2017 to 17 May 2020, small baseline subset interferometry synthetic aperture radar (SBAS-InSAR) technology was employed to obtain the time-series residual surface deformation. Validation of the SBAS-derived results is performed by comparing with the results obtained via leveling measurements. The root mean square error (RMSE) between SBAS-derived and leveling measurements results was found to be 1.144 mm, reflecting a fairly good agreement. Furthermore, the ordinary Kriging interpolation approach was adopted to obtain information on the deformation across the entire area. The spatial–temporal evolution characteristics of the derived subsidence bowls in multiple mined-out areas were revealed. The deformation characteristics for the abandoned mined-out areas in different periods were not completely consistent. Finally, the potential mechanism underlying the inconsistency in the subsidence associated with underground coal exploitation is analyzed. The findings of this study can provide insights into local construction and ecological improvement as well as guidance for the prediction of deformation in abandoned mined-out areas.